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Biomedical subjects

C Block

Publications and source records attributed to C Block.

At least 91 records · Page 5Linked to original sources
PubMed1990

Probing of active site residues of the zinc enzyme 5-aminolevulinate dehydratase by spin and fluorescence labels.

5-Aminolevulinate dehydratase from bovine liver requires Zn(II) for its activity and is inhibited by micromolecular concentrations of Pb(II). To elucidate the structure of the active site and its interactions between the active site and the metal binding site we labeled the active site for fluorescence studies and ESR spectroscopy. o-Phthalaldehyde reacted with active site lysyl and cysteinyl residues to form a fluorescent isoindole derivative. The fluorescence energy was independent of the deprivation of Zn(II) and of its substitution by the inhibitory Pb(II). For ESR-studies five iodoacetamide and four isothiocyanate pyrrolidine-N-oxyl derivatives with various spacer lengths were used to label the active site cysteinyl and lysyl residues, respectively. The ESR spectra of the modified enzyme preparations exhibited a significant immobilization of all labels, even with the longest spacers employed. Obviously the reactive cysteine is buried more than 12 A, and the active site lysine more than 11 A in a cleft of the enzyme structure. Zn(II) deprivation from the iodoacetamide spin-labeled enzyme caused a marked reversible increase in label mobility, whereas the Pb(II) substituted enzyme exhibited a smaller mobilization of the label. These results are interpreted by a model of the active site where the reactive cysteinyl and the lysyl side groups are close enough to be crosslinked by o-phthalaldehyde within a distance of 3 A. A structural role is assigned to Zn(II) in the enzyme, since Zn(II) deprivation does not alter the fluorescence of the isoindole derivative and increases the mobility of the cysteine-bound spin labels in the active site cleft.

Apoenzymes↗
PubMed1989

Immunoglobulin M, A, and G antibody response to lipopolysaccharide O antigen in symptomatic and asymptomatic Shigella infections.

The antilipopolysaccharide antibody response in sera obtained from subjects involved in 10 outbreaks of shigellosis occurring in Israeli military field units was determined by an enzyme-linked immunosorbent assay and a passive hemagglutination test. Both tests were found to be sensitive and specific for the diagnosis of shigellosis. A significant antibody response was detected in 73 to 82% of the symptomatic and 48 to 60% of the asymptomatic subjects during the Shigella sonnei and Shigella flexneri outbreaks. Fifty percent of the symptomatic and none of the asymptomatic subjects showed a significant antibody response in the Shigella boydii outbreaks. An examination of the kinetics of the antibody levels over a 10-week period after the onset of disease revealed that immunoglobulin A (IgA) levels were highest 2 weeks after infection and had declined to initial levels within 2.5 months. In contrast, IgG levels at the late convalescent stage were half those measured at early convalescence, still being about twice as high as the initial titers. Although the IgM levels showed a pattern similar to that of IgA, their elevation at the early convalescent stage was less pronounced. We conclude that the detection of an increase in the level of the IgA fraction appeared to be the best indicator for recent symptomatic, as well as symptomatic, infections due to Shigella organisms.

Adult↗
PubMed1989

Apparent effect of immune serum globulin prophylaxis in the military on viral hepatitis incidence in the civilian population in Israel.

Since 1969, extensive use of immune serum globulin in the Israel Defence Force for prophylaxis against hepatitis A virus (HAV) infection has produced a sharp decline in the incidence of the disease. However, it is not clear whether this policy has affected the susceptibility of Israeli adults to HAV infection. In this study, we examined the effect of the immunisation policy on the incidence of hepatitis A virus infection in the civilian population in the 15-44 year age group, which includes all those who have completed compulsory military service since vaccination was introduced. The incidence of viral hepatitis in the Jewish civilian population aged 15-44 increased by approximately 50% 3-4 years after the implementation of the immunisation policy. This rise was not seen in the non-Jewish population of the same age nor among Jews aged 45-64. These findings strongly suggest that the immunisation policy in the military prevents both clinical and sub-clinical disease, but has had the effect of producing more susceptible people at an older age in the civilian population.

Adolescent↗
PubMed1989

Saksenaea vasiformis infection in a burn wound.

Saksenaea vasiformis was isolated, after 18 days, from a burn wound caused by a petrol bomb. The fungus was locally invasive and was treated successfully by excision and systemic administration of amphotericin B. Identification of the isolate was accomplished by inducing sporulation on 1% agar containing grass clippings and on hay infusion agar.

Adult↗
PubMed1987

A prospective epidemiologic study of shigellosis in the Israel Defense Forces: implications for the use of shigella vaccines.

Recent development of new shigella vaccines has renewed interest in the current epidemiology of shigellosis in endemic regions. A prospective epidemiologic study of 5,774 soldiers was carried out in the Israel Defense Forces, between the months of May and September 1984. Shigellosis was found to be responsible for half the diarrhea epidemics and only rarely presented as sporadic cases of diarrhea. The epidemics occurred after exposure to field conditions, whereas under fixed military base conditions the finding of a case of shigellosis generally was not associated with an epidemic spread of the disease. It was concluded that, in this population, effective shigella vaccines may provide an important means of preventing epidemics of shigellosis in military units operating outside of permanent bases.

Adolescent↗
PubMed1986

Immunogenicity of a single dose of trivalent influenza vaccine including A/Philippines (H3N2): results of a field trial.

During 1982, a new A(H3N2) influenza virus subtype, A/Philippines/2/82, was identified, and this strain was combined with previous A(H1N1) and B influenza virus strains in the trivalent inactivated vaccine recommended for the 1983-1984 influenza season. Prior to the widescale use of this vaccine in Israel, a group of 106 young male soldiers was vaccinated under controlled conditions. Before vaccination, antibody titers greater than or equal to 1:40 were found in 14.1% against A/Philippines (H3N2), 18.1% against A/England/333/80 (H1N1), and 13.3% against B/Singapore/222/79. Two weeks following vaccination, 78.9% of the vaccinees for whom repeated blood samples were available, had antibody titers in this range for A/Philippines (H3N2), 92.9% for A/England (H1N1), and 80.0% for B/Singapore. The vaccine was only mildly reactogenic, and there were no cases of absence from work following vaccination. Thus the antibody response of young subjects to a single dose of a vaccine containing a new A(H3N2) subtype was found to be satisfactory, and the side effects experienced were minimal.

Antibodies, Viral↗
PubMed1986

Polymorphonuclear leukocyte adherence and chemotaxis in stressed and healthy neonates.

Defects in polymorphonuclear neutrophil (PMN) adherence and chemotaxis in neonates are thought to be an important cause of their increased susceptibility to overwhelming bacterial infection. Few studies of these functions have been carried out in stressed neonates who are at even greater risk of infection. PMN adherence and chemotaxis were examined in 33 stressed neonates with acute lower respiratory illness, 13 healthy neonates, and 43 healthy adults using whole blood PMN adherence and chemotaxis assays. PMN chemotaxis was significantly decreased in stressed neonates (locomotion index of 38.4 +/- 9.7 micron) compared with that of healthy neonates (48.9 +/- 12.8 micron, p less than 0.01) or adults (61.6 +/- 11.9 micron, p less than 0.001). PMN chemotaxis was studied during illness and recovery in 13 of the 33 stressed neonates and showed significant improvement during recovery (41.6 +/- 9.9 and 53.2 +/- 11.9 micron, respectively, p = 0.012). PMN adherence was decreased in stressed neonates (1.4 +/- 1.6%) compared with that of adults (12.3 +/- 11.4%, p less than 0.01) but was similar to that of healthy neonates (1.1 +/- 1.4%). These findings suggest that further impairment of PMN chemotaxis in stressed neonates helps account for their increased susceptibility to overwhelming bacterial infection.

Adult↗
PubMed1986

Aquarium-borne Mycobacterium marinum skin infection. Report of a case and review of the literature.

A 33-year-old fish fancier developed a protracted skin infection that ultimately was found to be caused by Mycobacterium marinum. The organism was isolated from the lesion as well as from infected fish taken from his home aquarium. The lesion resolved after a six-week course of oral sulfamethoxazole and trimethoprim. Forty-four additional cases of culture-proved M marinum skin infections acquired from aquariums and reported in the English-language literature are reviewed. Almost universally, the lesions remained circumscribed and were either single nodular (14 patients) or multiple sporotrichoid (31 patients). Diagnosis was supported by acid-fast smears (15 patients) and isolation of the organism from skin lesions (43 patients) or from fish (two cases). In vitro studies, as well as clinical outcomes, suggest sulfamethoxazole-trimethoprim or ethambutol hydrochloride plus rifampin to be the drugs of choice.

Adult↗
PubMed1982

The role of bougienage in the management of achalasia--the need for reappraisal.

Passive dilatation, advocated in the past by a number of gastroenterologists as the initial therapy for achalasia, has fallen into disrepute in the last 15 years. Our recent experience with five achalasia patients, four of whom were judged too fragile for esophageal myotomy or forcible dilatation, indicates the need for reappraisal of bougienage therapy.

Adult↗