Plants produce essential oils in the form labdanum buy penegra now mens health malaysia, ylang ylang discount penegra 100mg fast delivery man health journal, patchouli, orris; may of globules in or on the surface of the plant tissues irritate skin as a way to ensure their environmental safety. The oils may attract beneﬁcial insects and ward off • Almond: sweet; Prunus amygdalus, P. Some healers believe the oil is the essence also known as Hibiscus abelmoschus (family, Mal- of the plant and therefore its vital force, or energy, vaceae); sweet, ﬂoral, musky aroma that inten- which can be used therapeutically. There is evidence of distil- balancing, calming; emollient aphrodisiac; lation devices used more than 5,000 years; ancient blends well with neroli, olibanum, rose, sandal- Egyptians, for example, used essential oils for wood, other ﬂoral oils many purposes, such as mummiﬁcation and cos- metics. Ancient Babylonians, Chinese, Asian Indi- • Amyris: woodsy; Amyris balsamifera, Schimmelia ans, Greeks, and Romans documented their use of oleifera (family, Rutaceae); for stress relief, mus- essential oils, which may be blended for intensiﬁed cle relaxation, and a meditation aid; also known effects. Synthetic oils are not considered for use by as sandalwood amyris; from wood, West Indies; healers because they lack the energy of a living production method: steam distillation; blends organism. Among the many oils are the following: well with lavandin, citronella, cedarwood 107 108 oils, essential • Angelica root: earthy, musky; Angelica archangel- counteract fatigue and stress; blends well with ica, A. John’s wort: Hypericum perforatum (family, used also as antiseptic, hair tonic, before- and Guttiferae); antidepressant, calming, stress- after-sports rub; helps ﬁght water retention, reducing, mood-elevating; reduced aches, pains, 118 oils, herbal and menstrual discomfort; do not use before • Vetivert: woodsy; Vetivera zizanoides, Andropogon going out in the Sun muricatus (family, Poaceae [Gramineae]); also • Styrax (liquidambar Levant storax, or Storax): known as vetiver; relaxing, grounding, sensual, Balsam styracis, Liquidambar orientalis, (family, earthy, smoky; helps reduce blood pressure; Steracaceae); believed to help remove cellulite from roots, Haiti; production method: steam dis- and break down lymphatic deposits, reduce tillation; blends with lavender, sandalwood, and inﬂammation, and enhance mood jasmine • Tangerine: citrus; Citrus reticulata (family, • Violet leaves: herbaceous; Viola odorata; calming Rutaceae); sweet, tangy; used as astringent for (family, Violaceae); used as soothing agent, skin oily skin, and in drinks and desserts; not for use conditioner; from leaves, France and Egypt; pro- in the Sun duction method: solvent extraction; blends well with clary sage, basil • Tarragon: citrus; Artemisia dracunculus (family, Asteraceae [Compositae]); energizing; said to • Wintergreen: minty; Gaultheria procumbens (fam- relieve aches, pains, and menstrual discomfort ily, Ericaceae); cleansing; harmful or fatal if and improve mental alertness; also used as taken internally; may irritate skin; not for use astringent; from fruit peels, United States; pro- during pregnancy duction method: expression; blends well with • Yarrow: Achillea millefolium (family, Asteraceae basil, bergamot, chamomile, clary sage, [Compositae]); sedative properties; used for olibanum, geranium, grapefruit, lavender, chest infections, digestive problems, nervous lemon, lime, neroli, orange, rose exhaustion, menstrual problems, rheumatism, • Tea tree: camphoraceous; Melaleuca alternifolia, acne, scarring, burns, cuts M. Kaufman is the author of Happiness Is orthomolecular medicine The practice of pre- A Choice (New York: Fawcett Columbine, 1991), venting and treating disease by providing the body and other books. He and his wife, Samahria (Suzi with optimal amounts of substances that are nat- Lyte) Kaufman, operate the Institute in Shefﬁeld, ural to it. In nine reports, Pauling pro- organ remedies In Chinese traditional medicine, vided a rational basis for the use of optimal, even homeopathy, and Ayurvedic medicine, herbal if large, doses of nutrients. His theory explained remedies corresponding to the body’s organs and how evolution was shaped by the loss of the their disease or dysfunction and to the whole indi- chemical machinery required to make essential vidual’s status. His ﬁrst paper appeared in 1970, his last may be prescribed for disorders of the spleen and one in 1992. The optimum amounts of this vitamin, many of the idea that “the herbs are organs” is derived from the world’s major diseases would vanish. The National writings of the Swiss alchemist and physician Academy of Sciences refused to accept Dr. Orthomolecular medicine maintains that genetic factors are pivotal to both the structure of the body and its biochemicals. In the presence or event of a biochemi- Physical, Emotional, and Sexual Wellness (Pittsburgh, cal anomaly, diseases including atherosclerosis, Pa. Correcting the amount of Ornish, Dean American physician; assistant clin- vitamins, amino acids, trace elements, or fatty acids ical professor of medicine and attending physician in order to correct the biochemical abnormality is a at the School of Medicine, University of California, major goal of orthomolecular therapy. San Francisco; and attending physician at the Cali- Hoffer also wrote in The Journal of Orthomolecular fornia Paciﬁc Medical Center in San Francisco. A graduate of Baylor College of Medicine, Schizophrenia Association, we published the ﬁrst he was a clinical fellow in medicine at Harvard issue of a journal called the Journal of Schizophrenia. Medical School and an intern and medical resident We had to create our own journals because it was at Massachusetts General Hospital. Ornish is the impossible to obtain entry into the ofﬁcial journals author of books including Dr. Before 1967 I had not for Reversing Heart Disease (New York: Ballantine found it difﬁcult to publish reports in these jour- Books, 1990). One complete system of health care, based on broad of the assistant editors of the American Psychiatric principles that offer a way of thinking and acting in Association Journal announced that he would never relation to questions of health and disease. He had been the chairman of the task force mote healthy functioning by correcting mechanical which had out of hand condemned any of this imbalances within and between the structures— work. This new journal was to become the forum muscles, bones, ligaments, organs, and fascia (thin available to practitioners of the new psychiatry layers of tissue under the skin)—of the body. Even today the The name osteopathy, derived from the Greek Medical Index will not abstract our journals using osteon (bone) and pathos (to suffer), that is, “disease the excuse that they do not have enough money. Still, who viewed the muscu- protect the establishment from ideas that run loskeletal system as the vital mechanism of the counter to their own. In 1972 the title integrity of the whole body is seen as one of the was changed to the Journal of Orthomolecular Psychi- most important factors in health and disease. Linus Pauling in 1968 had proposed the physiology and clinical methods of investigation. Excerpted from the book Discovering that psychiatrists remained singularly disinterested Osteopathy (Berkeley, Calif. This is not limited to the cell—it involves the ing_osteopathy) recounts that an example might functioning of the whole of the physical body—and be “a six-year-old boy who, while playing, falls it gives us an insight into our mechanisms for sur- very hard on his bottom. A ory” contained by bodily cells, according to kiss and ‘rub it better’ console him. During a sud- osteopathic theory, leads to the idea of the body’s den growth spurt as a teenager, the same boy com- requirement for the least possible therapeutic or plains of low backache. In his late twen- itself—within certain limits—the capacity for self- ties, married with a young child and a stressful job, repair and correction. It can create its own reme- he begins to have an irritable colon and attacks of dies, provided that good circulation is maintained, cystitis. At a balanced diet is eaten, a positive attitude is held, the age of forty, he has a major attack of low back and—as far as possible—the individual lives in a pain and sciatica and is in bed for two weeks. The self-healing this point, hoping to avoid surgery, he visits an mechanism is the backbone and sustainer of the osteopath. Since the time of Hippocrates, the belief in the Osteopaths believe that disease primarily originates self-healing capacity of the body has been acknowl- in the individual, and so they concentrate on the edged. Still resurrected the innate healing con- person who is suffering rather than on the cept before the discovery of the law of homeostasis. Homeostasis, a scientiﬁc term for balance, is the There are, however, some stages of disease when process by which every living thing adapts in order the changes it has brought about have passed the to keep itself stable and function to the best of its point of return. Homeostasis is a self-regulating activity, with people to function to the best of their ability, given preset limits such as, in the blood there must be a the circumstances. Where necessary, an osteopath precise quantity of dissolved oxygen within maxi- will refer a patient for further specialist examina- mal and minimal levels that keeps body tissues tion and treatment. His work was carried was there in the two persons that caused one to have on and extended by his son, Bartlett J. This discovering the principles which comprise the question had worried thousands for centuries and method known as Chiropractic,” Palmer wrote in was answered in September, 1895. I had discovered that many dis- years that he could not hear the racket of a wagon eases were associated with derangements of the on the street or the ticking of a watch. In the dim ages inquiry as to the cause of his deafness and was of the past when man lived in rude huts and rocky informed that when he was exerting himself in a eaves, even up to the present time, he resorted to cramped, stooping position, he felt something give charms, necromancy and witchcraft for the relief of way in his back and immediately became deaf. His whole object examination showed a vertebra racked from its was to ﬁnd an antidote, a speciﬁc for each and normal position. I reasoned that if that vertebra every ailment which could and would drive out the was replaced, the man’s hearing should be intruder, as though the disorder was a creature of restored.
However buy penegra 50mg without a prescription androgen hormone norepinephrine, the absence of "F508 and other common abnormalities would not rule out cys- tic fibrosis related to the less common genetic variants buy penegra 50 mg lowest price mens health 15 minute workout dvd. Since the identification of the genetic abnormality, trials of gene-replacement therapy have begun. She wants to have a second course of antibiotics because an initial course of amoxicillin made no difference. She teaches games, and the cough is troublesome when going out to the playground and on jogging. She had her tonsils removed as a child and was said to have recurrent episodes of bronchitis between the ages of 3 and 6 years. Her parents are alive and well and she has two brothers, one of whom has hayfever. Her chest is clear and there are no abnormalities in the nose, pharynx, cardiovascular, respiratory or nervous systems. The mean daily variation in peak flow from the recordings is 36 L/min and the mean evening peak flow is 453 L/min, giving a mean diurnal variation of 8 per cent. There is a small diurnal variation in normals and a vari- ation of #15 per cent is diagnostic of asthma. The family history of an atopic condition (hayfever in a brother), and the triggering of the cough by exercise and going out in to the cold also sug- gest bronchial hyper-responsiveness typical of asthma. Patients with a chronic persistent cough of unexplained cause should have a chest X-ray. When the X-ray is clear the cough is likely to be produced by one of three main causes in non-smokers. Around half of such cases have asthma or will go on to develop asthma over the next few years. A small number of cases will be caused by otherwise unsuspected problems such as foreign bodies, bronchial ‘adenoma’, sarcoidosis or fibrosing alveolitis. In this patient the diagnosis of asthma was confirmed with an exercise test which was associated with a 25 per cent drop in peak flow after completion of 6 min vigorous exer- cise. Alternatives would have been another non-specific challenge such as methacholine or histamine, or a therapeutic trial of inhaled steroids. After the exercise test, an inhaled steroid was given and the cough settled after 1 week. The inhaled steroid was discontinued after 4 weeks and replaced by a $2-agonist to use before exercise. However, the cough recurred with more evident wheeze and shortness of breath, and treatment was changed back to an inhaled steroid with a $2-agonist as needed. If control was not established, the next step would be to check inhaler technique and treatment adherence and to consider adding a long-acting $2-agonist. In some cases, the persistent dry cough associated with asthma may require more vigorous treatment than this. Inhaled steroids for a month or more, or even a 2-week course of oral steroids may be needed to relieve the cough. The successful management of dry cough relies on establishing the correct diagnosis and treating it vigorously. Twenty-four hours previously she developed a continuous pain in the upper abdomen which has become progressively more severe. Her past medical history is notable for a duodenal ulcer which was successfully treated with Helicobacter eradication therapy 5 years earlier. She smokes 15 cigarettes a day, and shares a bottle of wine each evening with her husband. She is tender in the right upper quadrant and epigastrium, with guarding and rebound tenderness. Cholecystitis is most common in obese, middle-aged women, and classically is triggered by eating a fatty meal. Continued secretion by the gallbladder leads to increased pressure and inflammation of the gallbladder wall. Ischaemia in the distended gallbladder can lead to perforation causing either generalized peritonitis or formation of a localized abscess. Alternatively the stone can spontaneously disimpact and the symptoms spontan- eously improve. Gallstones can get stuck in the common bile duct leading to cholangitis or pancreatitis. Rarely, gallstones can perforate through the inflamed gallbladder wall into the small intestine and cause intestinal obstruction (gallstone ileus). The typical symptom is of sudden-onset right upper quadrant abdominal pain which radiates into the back. There is usually guarding and rebound tenderness in the right upper quadrant (Murphy’s sign). If the serum bilirubin and liver enzymes are very deranged, acute cholangitis due to a stone in the common bile duct should be suspected. The abdominal X-ray is normal; the major- ity of gallstones are radiolucent and do not show on plain films. Differential diagnosis The major differential diagnoses of acute cholecystitis include perforated peptic ulcer, acute pancreatitis, acute hepatitis, subphrenic abscess, retrocaecal appendicitis and perforated carcinoma or diverticulum of the hepatic flexure of the colon. Chest X-ray should be per- formed to exclude pneumonia, and erect abdominal X-ray to rule out air under the diaphragm which occurs with a perforated peptic ulcer. The patient should be kept nil by mouth, given intravenous fluids and commenced on intravenous cephalosporins and metronidazole. The patient should be examined regularly for signs of generalized peritonitis or cholangi- tis. If the symptoms settle down the patient is normally discharged to be readmitted in a few weeks once the inflammation has settled down to have a cholecystectomy. Her appetite is unchanged and normal, she has no nausea or vomiting, but over the last 2 months she has had an altered bowel habit with constipation alternating with her usual and normal pattern. She has smoked 20 cigarettes daily for 48 years and drinks 20–28 units of alcohol a week. No lymphadenopathy is detected, and her breasts, thyroid, heart, chest and abdomen, including rectal examination, are all normal. A barium enema revealed a neoplasm in the sigmoid colon, con- firmed by colonoscopy and biopsy. Chest X-ray and abdominal ultrasound showed no pul- monary metastases and no intra-abdominal lymphadenopathy or hepatic metastases respectively. She proceeded to a sigmoid colectomy and end-to-end anastamosis, and was regularly followed-up for any evidence of recurrence. Rectal bleeding, alteration in bowel habit for longer than 1 month at any age, or iron-deficient anaemia in men or postmenopausal women are indi- cations for investigation of the gastrointestinal tract.
Withdrawal of the antibacterial drug is recoverable from the duodenum regardless of the dose and the introduction of oral metronidazole or vancomycin schedule purchase 50 mg penegra with visa prostate 44. This motility disorder of the gut affects approximately 10% of Supplements of pancreatin are given to compensate the population buy penegra 100 mg with amex androgen hormone names. Although the symptoms are mostly colonic, for reduced or absent exocrine secretion in cystic fibrosis, patients with the syndrome have abnormal motility through- pancreatectomy, total gastrectomy and chronic pancreatitis. The important management prin- ations are best taken with or immediately before or after food. Psychological factors may be important precipitants or food, excessive heat should be avoided. Drug treatment is sympto- adjusted according to size, number and consistency of stools matic and often disappointing. Pancreatin can irritate the perioral skin and buccal mucosa • Anticholinergic drugs, such as hyoscine, have been if it is retained in the mouth and excessive doses can cause used for many years, although evidence of their perianal irritation. The oral use of better absorbed intestinal ones including nausea, vomiting and abdominal anticholinergics, such as atropine, is limited by their side discomfort. Asparaginase Oestrogens • Antidiarrhoeal drugs, such as loperamide, reduce Azathioprine Pentamidine associated diarrhoea. In general, however, they Ethanol sulfasalazine should be avoided for such a chronic and benign Tetracycline condition because of their serious adverse effects (see Thiazides Chapters 19 and 20). In severe liver dysfunction, neuropsychiatric changes occur Cellular damage due to free radical excess can produce multi- and can progress to coma. Intravenous administration of acetyl- these changes is not established, but it is known that in hepatic cysteine is used prophylactically in some centres to enhance coma and pre-coma, the blood ammonia concentration glutathione synthesis and thereby reduce oxidant (free rad- increases. In many patients, the time-course of encephalo- ical) stresses by scavenging these reactive entities. Orally Treatment of hepatic encephalopathy includes the follow- administered nitrogenous compounds (e. Bacterial degradation products purgatives to reduce the bacterial production of ammonia; of nitrogenous material within the gut enter the systemic cir- • oral or rectal administration of non-absorbable antibiotics, culation because of a failure of first-pass hepatic extraction such as neomycin, to reduce the bacterial population of (due to hepatocellular damage), or due to bypass of the hepa- the large bowel. Neomycin, 1–2g four times daily, is often tocytes by collateral circulation or intrahepatic shunting. It should be remembered, if the patient also has Another source is urea, which undergoes enterohepatic renal impairment, that neomycin may accumulate and circulation and yields approximately 3. This disaccharide Ammonia diffuses into the blood across the large intestine is not a normal dietary constituent and humans do not epithelium, where it is trapped by becoming ionized due to possess a lactulase enzyme, so lactulose is neither the lower pH of blood compared to colonic contents. These trap ammonia and concentrations, and methionine can provoke encephalopathy other toxins within the intestinal lumen by reducing its without causing a significant rise in blood ammonia concen- pH, and in addition they act as a cathartic and reduce tration. Furthermore, ammonia toxicity affects the cortex but ammonia absorption by reducing the colonic transit time; not the brainstem, which is also involved in encephalopathy. Vitamin K is given • Intestinal bacterial decarboxylation produces and fresh frozen plasma or platelets are used as required. To date, a clear-cut response in variceal oxazepam are preferred to those with longer-lived bleeding has not been demonstrated. The hazards of narcotic analgesics to the ing, anorexia, abdominal pain, diarrhoea, headache and dizzi- patient with acute or chronic liver disease cannot be over- ness. Newer vasoactive drugs, such as terlipressin, appear to emphasized; have a better therapeutic index and fewer side effects, although • prophylactic broad-spectrum intravenous antibiotics, terlipressin has a short half-life and needs to be administered especially if there is evidence of infection (e. While up to 90% of patients with acute hepatitis B clear the virus spontaneously, up to 60% of those with hepatitis C virus do not do so. Hepatocytes infected with hepatitis B virus raised blood pressure in the portal system and are of clinical produce a variety of viral proteins, of which the ‘e’ antigen importance because of their tendency to bleed. Pegylation (polyethylene glycol- blood flow through splanchnic arterial constriction. Terlipressin and octreotide are used to reduce is unsuccessful, if relapse occurs following successful initial portal pressure urgently, to control bleeding before more defini- interferon treatment, or if interferon is poorly tolerated or con- tive treatment, such as sclerotherapy or variceal banding. Details its long-acting analogue octreotide reduce blood flow and cause on the regimens can be found at www. If the transaminases reach more than twice, and/or drug itself or its metabolites may affect liver function. It is preventable, since obese hepatotoxicity is used to classify those reactions that are ‘idio- patients are fat because they eat too many calories for their syncratic’ and usually unpredictable (Table 34. Naturally, a calorie-controlled diet and adequate the resulting liver disease may be related to dose or to duration but sensible amounts of exercise are the essentials of treatment. Particular drugs tend to produce distinctive patterns Unfortunately, the results of treating patients at weight-reduc- of liver injury, but this is not invariable (see also Chapter 12). Unfortunately, the causes of obesity are only currently being more comprehensively studied. If the patient is being Leptin is thought to be a blood-borne signal from the adipose treated for a disease associated with hepatic dysfunction, partic- tissue that informs the brain about the size of an individual’s ularly with multiple drugs, identification of the responsible fat mass. Elderly are at particular risk Tolbutamide Cholestatic jaundice Telithromycin Hepatocellular damage Isoniazid Hepatitis Mild and self-limiting in 20% and severe hepatitis in 0. Possibly more common in rapid acetylators Pyrazinamide Hepatitis Similar to isoniazid, but more clearly related to dose Methyldopa Hepatitis About 5% of cases have subclinical, raised transaminases; clinical hepatitis is rare Phenytoin Hypersensitivity reaction Resembles infectious mononucleosis; pharmacogenetic predisposition; cross-reaction with carbamazepine Isoniazid Chronic active hepatitis Associated with prolonged treatment, usually regresses when drug is discontinued Nitrofurantoin Dantrolene Halothane } Hepatitis/hepatic necrosis See Chapter 24 Ketoconazole and metabolic control pathways, as well as its exact effects on common effect. In the future, modula- mine were associated with less abuse potential, but have been tion of leptin activity may provide a target for treating obesity. It reduces appetite and is used as an adjunct to diet for there is no doubt that starvation leads to weight loss. Therefore, research into drugs for the treatment of obesity has Contraindications include major psychiatric illness, ischaemic concentrated on finding substances that inhibit appetite. Learned behaviour is probably important in determining Side effects include dry mouth, nausea, abnormal taste, consti- the frequency of eating and whether food is taken between pation, myalgia, palpitations, alopecia, seizures and bleeding major meals. Rimonabant is con- important satiety factor released from the gastro-intestinal traindicated in (and may cause) depression. Amphetamines and related drugs suppress appetite but are Orlistat, is an inhibitor of gastro-intestinal lipases, reduces toxic and have considerable abuse potential. The site of action of fat absorption and is licensed for use to treat obesity in combin- amphetamines appears to be in the hypothalamus, where they ation with a weight management programme, including a increase noradrenaline and dopamine concentrations by caus- mildly hypocaloric diet. Cardiovascular weight reduction is less than 10% after six months, treatment effects are frequently observed with amphetamines, a dose- should be stopped. Weight gain occurs during treatment with various Substances such as methylcellulose and guar gum act as bulk- other drugs, including atypical neuroleptics, e. A high-fibre diet may help weight loss, provided that well as the oral contraceptive pill. Glucocorticosteroids may total caloric intake is reduced, and is desirable for other rea- help to improve appetite in terminally ill patients.
Filtration A) Autoclaving Autoclaving is used to sterilize most agar and fluid culture media discount generic penegra canada androgen hormone supplements. O B) Steaming at 100 C It is used to sterilize media containing ingredients that would be O inactivated at temperature over 100 C and re-melt previously bottled sterile agar media purchase genuine penegra on-line prostate cancer john hopkins. C) Filtration It is used to sterilize additives that are heat-sensitive and can not be autoclaved. Turbidity in fluid media and microbial growth in solid media confirm contamination. Addition of heat-sensitive ingredients Refrigerated-heat sensitive ingredients should be warmed at room temperature before added to a molten agar medium. Using an aseptic technique, the ingredients should be added when O the medium has cooled to 50 C, and should be distributed immediately unless further heating is required. Dispensing of culture media Media should be dispensed in a clean draught-free room using aseptic technique and sterile container. Dispensing agar media in petridish • Lay out the sterile petridishes on a level surface. Quality control • Inoculate quarter plates of the medium with a five hours broth culture for each control organism. Storage of culture media • Dehydrated culture media and dry ingredients should be stored at an even temperature in a cool dry place away from direct light. Aseptic technique during inoculation of culture media • Decontaminate the workbench before and after the work of the day. Sterlizing the Inoculating the fluid inoculating loop media with sterilized with flame loop Fig. Before inoculating a plate of culture media, dry the surface of the O media by incubating at 37 C for 30 minutes. To inoculate a plate, apply the inoculum to a small area of the plate (‘the well’) using sterile wire loop and then spread and thin out the inoculum to ensure single colony growth. Inoculation of slant media To inoculate slant media, use a straight wire to streak the inoculum down the center of the slant and then spread the inoculum in a zigzag pattern. Optimal temperature, humidity and gaseous atmosphere should be provided for microorganisms to grow best. Anaerobic atmosphere is essential for the growth of strict anaerobes, and the techniques for obtaining anaerobic conditions are the following:. Bacterial structural components and the macromolecules for the metabolism are synthesized from the elements. The four most important elements of bacteria are carbon, hydrogen, oxygen and nitrogen. Carbon Organisms require a source of carbon for the synthesis of numerous organic compounds that comprise protoplast. Autotrophs: Free-living, non-parasitic bacteria which use carbondioxide as carbon source. Heterotrophs: Parasitic bacteria require more complex organic compounds as their source of carbon and energy. Growth factors Growth factors are organic compounds that are required by micro- organisms in small amounts which the cell can not synthesize from other carbon source. Auxotrophs: Mutant bacteria, which require an additional growth factor not needed by the parental or wild type strain. Generation time It is the time taken for the size of a bacterial population to double. Bacteria grow by taking nutrients and incorporate them into cellular components; then bacteria divide into two equal daughter cells and double the number. Bacterial growth phases The pattern in cell numbers exhibited by bacterial population obtained after inoculation Of a bacterium into a new culture medium. Cell division precedes at a logarithmic rate, and determined by the medium and condition of the culture. Maximal stationary phase The period when the bacteria have achieved their maximal cell density or yield. A bacterial population may reach stationary growth when one of the following conditions occur: 1. Decline phase The period at which the rate of death of bacterial cells exceeds the rate of new cell formation. Few organisms may persist for so long time at this period at the expense of nutrients released from dying micro-organisms. Viable plate count The most common method of estimating bacterial growth which involves counting the number of bacterial colonies grown on solid media after incubation of the inoculated media for 18-24 hours. Greater than 300 colonies on a plate are too close to distinguish as an individual colony forming unit (too numerous to count). Limitation of viable plate count: It selectively in favor of a certain group of bacterial population. Direct count It involves direct microscopic counting of bacteria in the sample using counting chamber. Turbidimetric method It is the method of determination of bacterial growth in liquid media. Factors influencing bacterial growth in vitro Not all bacterial species grow under identical environmental conditions. Each bacterial species has a specific tolerance range for specific environmental parameters. Out side the tolerance range environmental conditions for a bacteria to reproduce, it may survive in dormant state or may lose viability. Rates of bacterial growth are greatly influenced by the following environmental parameters. Temperature Temperature tolerance range: The minimum and maximum temperature at which a micro-organism can grow; which is different in different species of bacteria. Optimal growth range of temperature: The temperature at which the maximum growth rate occurs; and results in the shortest generation time of bacteria. Based on different optimal growth temperature requirement, bacteria are divided into: 54 Optimal growth temperature o 0. Oxygen Base on oxygen requirements and tolerance, bacteria are divided classified as:. Microaerophiles • Obligate aerobic bacteria grow only when free oxygen is available to support their respiratory metabolism. H P <7 is acidic H P =7 is neutral H P >7 ia alkaline H • Neutrophilic bacteria grow best at near neutral P value. High salt concentration disrupts membrane transport systems and denatures proteins of bacteria but halophiles have adaptive mechanisms to tolerate high salt concentration.