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Biomedical subjects

H Steinberg

Publications and source records attributed to H Steinberg.

At least 73 records · Page 4Linked to original sources
PubMed1994

In vivo administration of a monoclonal antibody against the type I IL-1 receptor inhibits the ability of mice to eliminate Mycobacterium paratuberculosis.

The purpose of this study was to determine the influence of endogenous interleukin-1 (IL-1) on resistance to paratuberculosis infection in experimentally infected gnotobiotic mice. Following a 6-month treatment with prednisolone to facilitate bacillary multiplication, control mice substantially reduced the numbers of M. paratuberculosis in the liver and ileum. In contrast, mice injected with a monoclonal antibody against the type I IL-1 receptor failed to reduce the numbers of M. paratuberculosis in the liver and ileum and exhibited more liver granulomas, which contained numerous acid-fast bacilli. These results indicate a significant role for endogenous IL-1 in host defense against experimental M. paratuberculosis infection in mice.

Animals↗
PubMed1994

Recombinant interleukin-12 enhances resistance of mice to Listeria monocytogenes infection.

The effect of recombinant murine IL-12 (rIL-12) or anti-IL-12 antibody administration on resistance to murine listeriosis was investigated. Mice given a single 0.5 micrograms dose of rIL-12 had 1.5 log10 fewer listeriae in their spleens and livers as compared with control infected mice 3 days after L. monocytogenes challenge. Conversely, administration of anti-IL-12 IgG caused an equivalent increase in the cfu of L. monocytogenes recovered from the spleens and livers as compared to control mice. This is the first report of such a protective effect from a single dose of rIL-12. Treatment of uninfected mice with rIL-12 induced IFN-gamma mRNA production in their livers. Infection of mice with L. monocytogenes caused a similar increase in IFN-gamma mRNA levels that was not increased further by concurrent treatment with rIL-12. Treatment of mice with an anti-IFN-gamma MAb eliminated the protective effect of IL-12 on Listeria infection. Expression of TNF-alpha, IL-10 and IL-12p40 mRNA in L. monocytogenes-infected mice were not significantly altered by administration of either anti-IL-12 IgG or rIL-12. rIL-12 administration was associated with increased serum AST levels, a measure of liver damage, 1 day after treatment in L. monocytogenes-infected mice. In addition, rIL-12 administration was associated with the increased presence of small inflammatory foci and necrotic hepatocytes in both infected and uninfected mice, suggesting a proinflammatory role for IL-12 in the liver.

Animals↗
PubMed1994

Aerobic exercise and Type A behaviour.

The Type A behaviour pattern is a well-documented, if controversial, risk factor for coronary heart disease. Surprisingly, relatively little work has been reported on ways of modifying this behaviour pattern. Aerobic exercise, with its demonstrated benefits for both cardiovascular reactivity and psychological 'well-being', is a promising treatment. The literature is reviewed and recommendations are made for practical applications and future research.

Behavior Therapy↗
PubMed1994

Administration of antigranulocyte monoclonal antibody RB6-8C5 prevents expression of acquired resistance to Listeria monocytogenes infection in previously immunized mice.

Recent studies have established the importance of neutrophils in innate resistance to Listeria monocytogenes infection in mice. The purpose of this study was to determine the importance of neutrophils in acquired resistance to L. monocytogenes infection. Previously immunized mice that were depleted of neutrophils by administration of the antigranulocyte monoclonal antibody RB6-8C5 demonstrated less resistance to L. monocytogenes challenge than did nonimmunized control mice. In contrast, immunized control mice exhibited a heightened resistance to rechallenge, as expected. These results suggest that neutrophils make previously unrecognized contributions to acquired immunity to a facultative intracellular pathogen.

Animals↗
PubMed1994

Skeletal muscle blood flow independently modulates insulin-mediated glucose uptake.

Insulin-mediated glucose uptake (IMGU) occurs principally in skeletal muscle. To directly examine whether skeletal muscle perfusion (F) can directly and independently modulate IMGU, we combined the hyperinsulinemic euglycemic clamp and leg balance techniques [leg glucose uptake (LGU) = arteriovenous glucose difference (delta AVG) x F]. Young (< 40 yr) healthy lean subjects were studied during euglycemic hyperinsulinemia of approximately 23 microU/ml (group I, n = 8) and approximately 950 microU/ml (group II, n = 6). Femoral delta AVG and leg F were measured, and LGU was calculated at baseline after approximately 200 min of steady-state hyperinsulinemia alone and during a superimposed intrafemoral artery infusion of methacholine hydrochloride designed to increase leg F two- to threefold. In groups I and II, insulin raised the delta AVG approximately 4- and 14-fold, respectively (P < 0.0001). Leg F was unchanged during the low-dose insulin infusion (group I) but increased 112 +/- 35% in group II (P < 0.001). During methacholine infusion the delta AVG narrowed 35.9 +/- 6.8% (P < 0.01) and 20.5 +/- 4.8% (P < 0.05) in groups I and II, respectively. Leg F rose 224 +/- 30% (P < 0.01) and 79 +/- 13% (P < 0.05) above the flow rate achieved with insulin alone. Thus, during methacholine flow modulation, LGU increased 116 +/- 36% (P < 0.01) and 47 +/- 11% (P < 0.05) in groups I and II, respectively. In conclusion, skeletal muscle perfusion during hyperinsulinemia can act as an independent determinant of IMGU.

Adult↗
PubMed1993

Subclinical lumbar polyradiculopathy, polyneuritis and ganglionitis in aged wild and exotic mammalians.

Subclinical lumbar polyradiculopathy was present in the intradural dorsal and ventral nerve rootlets of 19 aged individuals of the following wild and exotic mammalian species: woodrat, raccoon, mink, lynx, reindeer, red deer, musk ox, scimitar-horned oryx, Arabian oryx, hybrid waterbuck, Persian onager, Przewalski's wild horse, Malayan sun bear, Asian elephant, East African river hippopotamus, vervet monkey and rhesus monkey. It was characterized by mild to severe multifocal ballooning of myelin sheaths. Occasionally, ballooned myelin sheaths contained thin strands of myelin and macrophages surrounding distorted axons. Additionally, a mild incidental lymphocytic polyneuritis was present in intradural nerve rootlets of the Malayan sun bear, and a moderate lymphocytic spinal ganglionitis in the East African river hippopotamus.

Age Factors↗
PubMed1993

A fibrosarcoma in the skeletal muscle of a capybara (Hydrochoerus hydrochaeris).

An 8-yr-old male capybara (Hydrochoerus hydrochaeris), a resident of an urban zoological collection in upstate New York (USA), had a mass posteroventral to its left stifle; it was of unknown duration. The mass was a fibrosarcoma based on invasive sheets of interwoven spindle-shaped neoplastic cells with moderate associated extracellular matrix composed of collagen fibers. Supportive immunohistochemical staining was positive for vimentin but negative for cytokeratins, desmin, and myoglobin. The animal subsequently died of unknown causes. This is the first known report of a neoplasm in a capybara.

Animals↗
PubMed1993

Intrauterine transmission of Borrelia burgdorferi in dogs.

To determine whether intrauterine transmission of Borrelia burgdorferi could exist in dogs, 10 female Beagles were inoculated intradermally with approximately 1,000 B burgdorferi on day 1 of proestrus; inoculation was repeated every 2 weeks during the gestation period. Ten female control Beagles were similarly inoculated with phosphate-buffered saline solution. Prior to the start of the study, all females and 3 males used for breeding were seronegative for B burgdorferi on the basis of results of the indirect fluorescent antibody test and immunoblot (western analysis. Similarly, results of culture of blood for B burgdorferi were negative. All 20 of the females were bred naturally. Blood samples were collected weekly for serologic testing and culture. Blood samples were obtained from live pups on day 1 of life, then weekly until pups were 6 weeks old when they were euthanatized. Tissues were obtained for culture and testing by use of polymerase chain reaction (PCR). Of 10 spirochete-inoculated (SI) females, 8 became infected with B burgdorferi as evidenced by spirochete culture results and/or PCR-detected B burgdorferi DNA in the tissues of females or their pups. Of the 10 SI females, 8 delivered litters (3 to 7 pups) that had at least 1 neonatal or 6-week-old pup with B burgdorferi DNA-positive tissues (by PCR), and spirochetes were cultured from tissues from pups of 2 litters.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Drug interactions represented by high resolution computer graphics.

The amount of backward walking induced in mice by co-administration of clenbuterol, a beta-adrenoceptor agonist and putative antidepressant, and the benzodiazepine chlordiazepoxide was plotted as a three-dimensional surface, using modified Uniras software. The surface was compared with the theoretical surface to be expected if the interactions between the two drugs were merely additive. The difference between the theoretical and the obtained surfaces was plotted and a functional representation of statistical variability was 'draped' over the difference model. The computer methods can be applied to small amounts of irregularly distributed data, and results are apparent from simple inspection, e.g. the highest peak of backward walking is also the most reliable statistically. The technique is useful for both laboratory and clinical studies.

Animals↗
PubMed1992

Erythropoietin response to acute normobaric hypoxia in humans.

Hypoxia causes an increased production of erythropoietin (EPO), but the time course of the EPO response in humans has not been well characterized. This study examines the relationship between the duration of normobaric hypoxic exposure and plasma EPO levels in healthy human subjects. Six volunteers breathed a gas mixture of 10.5% O2-89.5% N2 continuously for 5, 60, and 120 or intermittently for 240 min. O2 saturations were maintained between 75 and 85% during the exposure. Arterial pH was 7.467 +/- 0.019, PO2 37.05 +/- 2.43 Torr, and PCO2 36.69 +/- 2.05 Torr. O2 half-saturation pressures of hemoglobin were normal for all subjects. Plasma EPO was measured every 30 min for 360 min by radioimmunoassay. No increase in EPO was seen after the 5- and 60-min exposures. However, a 50% increase was seen 240 min after the initiation of the 120-min hypoxic exposure (P less than 0.01). Intermittent exposure resulted in an increase of EPO by 52% 360 min after the onset of exposure (P less than 0.05). Therefore, exposing humans continuously to an inspiratory O2 fraction of 0.105 for 120 min or intermittently for 240 min provides a sufficient stimulus to increase production of EPO.

Adult↗