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Biomedical subjects

I M Smith

Publications and source records attributed to I M Smith.

At least 91 records · Page 5Linked to original sources
PubMed1978

Effect of repeated injections of iron dextran on the haematological, serological and pathological changes in experimental avian tuberculosis.

Eight intramuscular injections of 200 mg/kg of iron (DFe), given as iron dextran twice weekly in the week before and the three weeks after intravenous infection with about 10(7.5) colony-forming units of Mycobacterium avium, significantly prolonged (by about 11 days) the mean 'time-to-death' of immature male fowl (Gallus domesticus) compared with corresponding regimes using dextran (Dx) only or saline, When a proportion of the birds were examined 21 days after infection many of the abnormalities associated with the disease, including a marked hypochromic anaemia, were less severe in DFe-treated than in the Dx- or saline-treated chicks and there were about 10- to 85-fold fewer viable tubercle bacilli in the liver and spleen of the DFe-treated birds.

Animals↗
PubMed1977

The influence of protein source and basal dietary component on survival in acute experimental fowl typhoid in the chick (Gallus domesticus).

1. The influence of diet on the survival of chicks inoculated orally at 15 d of age with Salmonella gallinarum was determined, and in the first experiment the numbers of salmonellae were counted in blood 5 or 7 d after inoculation to assess their value in predicting survival. 2. Significantly more chicks survived among those given beef powder as the protein supplement in a starch-based diet than among those where fish flour replaced beef powder. The number of salmonellae in blood was significantly higher in chicks given the fish-flour diet than in those given the beef-powder diet, but the relationship between the number of viable organisms in blood and the final survival rate was not close. 3. Whale meat and soya-bean protein gave high survival rates, similar to that given by beef powder, and casein plus gelatin was slightly poorer in this respect. 4. For each high-protein food the level of survival from the acute disease was significantly greater with wheat than with starch as the basal component of the diet. 5. The addition of either condensed beef extract or fish solubles to a standard diet did not influence survival.

Animals↗
PubMed1977

Adrenergic mechanisms in infection. III. alpha-and beta-receptor blocking agents in treatment.

Raised epinephrine concentrations concentrations developed in the blood of mice near death after an intraperitoneal challenge with 10(9) Staphylococcus aureus or Escherichia coli. Both epinephrine levels were elevated in the urine near death. These challenges were infections and not intoxications, as they could be successfully treated with antibiotics. Using the same model infections, we studied the effect of alpha-and beta-receptor blocking agents and other adrenergically active compounds. The compounds alone were not toxic in the doses used. alpha-Blockers, such as phenoxybenzamine, dibenamine, and ergotamine and beta-blockers, such as butoxamine, timolol, and practolol, were ineffective. Phentolamine alone or propranolol alone showed some evidence of an ability to prolong life in S. aureus infections. Together they lengthened life significantly in S. aureus-challenged mice. In E. coli infections this beneficial effect was not noted. Mice pretreated with reserpine (7 mg/kg) and challenged with S. aureus lived 55% longer than saline-treated controls. Less benefit was noted in E. coli infections. Serontonin treatment was helpful in S. aureus infections and deleterious in E. coli infections.

Adrenergic alpha-Antagonists↗
PubMed1977

Biochemically assisted antibiotic treatment of lethal murine Staphylococcus aureus septic shock.

Evidence has been sought for life-prolonging effects of a variety of chemicals given subcutaneously 1 hr after intraperitoneal challenge of mice with 10(9) Staphylococcus aureus cells. The chemicals were chosen to replace chemicals found to be missing in the blood or carcass at death or to treat biochemical or visible abnormalities in sick mice near death from infection. Nafcillin given subcutaneously in adequate amounts cure S. aureus infection. In these experiments nafcillin treatment was delayed until 40% of the time from challenge to death in the controls. Chemicals were given in addition to nafcillin subcutaneously 20% of the time from challenge to death. Cortisol, Dilantic, epsilon-aminocaproic acid, glucose, nicotinamide, olive oil, phentolamine-propanalol, sodium bicarbonate, sodium lactate, and reserpine each prolonged life compared to saline treatment. When nafcillin was added, only cortisol, Dilantin, nicotinamide and reserpine were found to prolong life significantly compared to nafcillin-saline treatment Fatality rates were significantly reduced with cortisol and Dilantin when they were given in association with nafcillin compared to nafcillin-saline treatment.

Animals↗
PubMed1977

Increased survival from acute Salmonella gallinarum infection in chicks given diets with high levels of some forms of iron.

Amounts exceeding 100 ppm of extra dietary iron as the ferric salts of ethylenediaminetetra-acetic acid (FeE) or nitrilotri-acetic acid (FeN) produced highly significant increases in survival among chicks infected with 10(6.4) living Salmonella gallinarum strain 9. Additional dietary iron (400 ppm) as the sulphate or chloride salts (or as ferric fructose) lacked activity comparable with FeE or FeN except when 0.2 per cent of NaE was also present in the diet. FeE iron (600 ppm) also diminished the severity of several of the pathological reactions which occur in chicks during the acute stage of experimental fowl typhoid. The enhanced survival and decreased severity of the pathological changes in infected chicks were associated with large reductions in the numbers of viable salmonellae in the spleen at the height of the acute infection.

Animals↗
PubMed1977

Experimental fowl typhoid in chicks impaired immunologically by treatment with cyclophosphamide.

Male chicks were injected intramuscularly with 6 mg of cyclophosphamide daily for three consecutive days, the initial dose being given on the day of hatching. This treatment impaired bursal development and lymphopoiesis and no circulating antibodies appeared after such chicks were injected with Salmonella gallinarum antigens at 19 and again at 26 days of age. In impaired chicks which were infected orally when 15 days old with S gallinarum the level of mortality was essentially the same as that in unimpaired animals. Impairment did not affect the lower mortality that accompanies feeding with a nutritionally adequate diet containing meat meal as the sole protein supplement in comparison with fish meal as the supplement. An anaemia was present in chicks examined seven days after infection. This anaemia was microcytic to a degree that either exceeded or approached statistical significance. As antibody-mediated hypersensitivity reactions involving the erythrocytes were absent in the impaired chicks, the anaemia must have differed in pathogenesis from the macrocytic anaemia of immunopathological orgin reported by others in adult females with acute fowl typhoid. A disturbance of iron metabolism could have accounted for the anaemia in the diseased chicks.

Anemia↗
PubMed1977

Life-threatening infections: how to choose the right antibiotics.

Pneumococcal pneumonia in two or more lobes in frail, elderly patients; staphylococcal and Gram-negative rod pneumonia in patients of any age; lung abscesses; septicemia; endocarditis; peritonitis; and meningitis are life-threatening infections. To save patients with these infections, the physician should know the causative organism and educate himself by cultures; estimate the whole body bacterial burden and decrease bacterial numbers by incision and drainage where large collections of pus are accessible; choose antibiotics with care and use two antibiotics if serious prognostic signs are present initially, if there is a change for the worse, or if the laboratory report indicates that multiple organisms are present; check the serum bactericidal level and repeat this test if the route of antibiotic administration is changed; watch for and treat underlying disease; and always monitor for septic shock. Aged patients need special care, as they often have severe underlying disease. The bacterial burden is often high before infection is recognized in elderly patients, and age itself interferes with host defenses.

Adult↗
PubMed1977

Cephalexin: clinical effectiveness in geriatric patients.

A clinical and bacteriologic study was done in 298 elderly patients who had infections that were treated with cephalexin. Satisfactory clinical responses occurred in 93% of the 44 patients with respiratory tract infections, 96% of the 27 patients with skin and soft tissue infections, and 87% of the 227 patients with urinary tract infections (15 had asymptomatic bacteriurial); bacteriologic responses were satisfacoty in 80, 74, and 72 percent, respectively. The clinical response to cephalexin treatment was the same in 283 patients over age 65 as in 902 patients 16 to 64 years of age. Only 7% of 934 elderly patients had adverse reactions, which were generally mild. The BUN, SGOT, and hematopoietic values showed no change. Thus, cephalexin can be recommended for the oral treatment of many common infections in the elderly.

Adolescent↗
PubMed1977

Enhancement of survival in acute experimental fowl typhoid in chicks by the administration of iron dextran.

Chicks aged 15 days were infected orally with 10(6-4) living Salmonella gallinarum. Iron from iron dextran or ferric ammonium citrate (DFe and CFe respectively), in doses of 2-0 or 0-4 mg/kg given intramuscularly at the time of infection, had no effect on subsequent mortality compared with infected controls. Increasing the amount of CFe to the maximum (20 mg/kg) that was non-toxic intramuscularly was also ineffective but when the dose of DFe was increased to 20 or 50 mg/kg the survival rate rose sharply. If given at other times in relation to the time of infection, or more frequently, 50 mg/kg or more of DFe was less active. The increased survival rate among infected chicks given 50 mg/kg of DFe at the time of infection was accompanied by decreases in the severity of the morbid changes in the disease, and by reductions of between c 10- to 100-fold in the numbers of viable S gallinarum in the liver, spleen or blood at the height of the acute infection. DFe (50 mg/kg) given at the time of infection also eliminated the difference in the survival rate noted previously between infected chicks fed respectively with diets containing fish or meat meal as the sole source of supplementary protein.

Anemia↗
PubMed1977

Altered absorption and regulation of iron in chicks with acute Salmonella gallinarum infection.

Chicks aged 15 days were infected orally with Salmonella gallinarum. During the six-day period immediately following infection the absorption of 59Fe from the gut fell progressively to be eventually about half that in noninfected chicks. This reduced uptake was accompanied by a shift in the distribution of the 59Fe absorbed, more occurring in the spleen and less in the liver and blood. During the eight-day period that immediately followed infection in another experiment, serum iron concentration on day 4 and 6 in infected chicks was significantly lower than that in noninfected birds. In the infected chicks also the transferrin saturation was significantly lower and the unsaturated ironbinding capacity higher, on days 4, 6, and 8 after infection. These findings show that there is a major disturbance in iron regulation in acute systemic bacterial infection in the immature fowl and suggest that the mild anaemia which occurs in chicks during acute S gallinarum infection a shortage of iron in the body.

Animals↗
PubMed1976

Relationship of porcine cytomegalovirus and B bronchiseptica to atrophic rhinitis in gnotobiotic piglets.

Both porcine cytomegalovirus (PCMV) and Bordetella bronchiseptica produced rhinitis and pneumonia when inoculated intranasally into young gnotobiotic pigs. With PCMV the nasal lesions were confirmed to the lamina propria, while Bordetella produced atrophy of the turbinate bones and hyperplasia and degeneration of the nasal epithelium. Some exacerbation of the lesions was observed in the nasal mucosa of pigs given both agents, but the degree of bone atrophy was not increased.

Animals↗
PubMed1975

Blood pressure changes in mice after lethal staphylococcal infection and endotoxin challenge.

A radioisotope technique has been used to determine blood pressure changes in mice after lethal staphylococcal infection and after lethal endotoxin challenge. The method was verified by making simultaneous direct measurements in rats. Mice in both groups became hypotensive to a similar level (a fall 20-30 mm Hg). This tailcuff technique is simple and reliable but is dependent upon normal tail blood flow. Spurious low pressure readings are obtained in hypothermic or chilled mice because the tail is a major thermoregulator organ. These difficulties can be overcome by warming chilled or hypothermic mice.

Animals↗
PubMed1975

Effects of glucagon and other peptides on fixation of CO2 by rat liver mitochondria.

Glucagon and glucagon fragments from the carboxyl terminal end of the protein act at 0.01 to 0.1 mM concentrations on isolated rat liver mitochondria to sustain the rate of fixation of CO2 in the presence of pyruvate. The rate of decarboxylation of pyruvate is also increased by these substances. Similar effects are found with bacitracin, vanocomycin and cephalothin but not with any other of the proteins, peptides and antibiotics tested. The action of glucagon requires the presence of added magnesum ion. The addition of glucagon results in a better maintenance of adenosine triphosphate (ATP), and it leads to a greater degree of swelling of the mitochondria during the incubation. The effect of glucagon is partially mimicked by atractyloside, but it appears that glucagon is not exerting its effect by an atractyloside-like action. Added ATP obliterates the effect of added glucagon by sustaining fixation of CO2 However in incubations made in the presence of lower than usual levels of inorganic phosphate (2 mM vs. 8 mM) an effect of glucagon can be seen in the presence of ATP.

Adenosine Triphosphate↗
PubMed1975

A study of 57 cases of actinomycosis over a 36-year period. A diagnostic 'failure' with good prognosis after treatment.

Actinomycosis continues to elude the clinician. In only four of 57 patients seen at the University of Iowa Hospitals (and in none of 12 since 1958) the disease was correctly diagnosed on admission. The disease is more common in men, but has no seasonal or occupational predilection. A normal inhabitant of the mouth, Actinomyces israelii acts as an opportunistic infection, usually in association with bacterial invasion. It tends to follow a break in normal mucosal barriers. Fistula and palpable mass are the physical hallmarks, with pain and fever the most frequent symptoms. Definitive identification requires anaerobic culture. Chances for cure are excellent with lengthy antibiotic administration.

Actinomycosis↗