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Biomedical subjects

H Steinberg

Publications and source records attributed to H Steinberg.

At least 55 records · Page 3Linked to original sources
PubMed1998

Mice lacking the murine interleukin-8 receptor homologue demonstrate paradoxical responses to acute and chronic experimental infection with Listeria monocytogenes.

In this study we demonstrate that mice which lack the murine interleukin-8 receptor homologue exhibit enhanced resistance during the early stage of infection (1-4 days after i.v. challenge with Listeria monocytogenes). This result is surprising in that interleukin-8 and other CXC chemokines are key players in the accumulation of inflammatory neutrophils, which is thought to be critical for resistance to listeriosis. Paradoxically, some of the interleukin-8 receptor knockout mice that survived acute infection with L. monocytogenes demonstrated evidence of chronic infection with L. monocytogenes.

Acute Disease↗
PubMed1998

Cerebellar medulloblastoma with multiple differentiation in a dog.

A 4-year-old female, spayed Border Collie Dog was brought to the Veterinary Medical Teaching Hospital for evaluation of a progressive head tilt and ataxia that were unresponsive to therapy. Neurologic examination localized a right-sided lesion. The owner refused additional diagnostic tests, and necropsy was performed after euthanasia. Gross findings included atrophy of the temporal muscles and a moderately well delineated, 2.5- x 1.5- x 1.0-cm, gray soft-tissue mass compressing the right cerebellar hemisphere and dorsal hindbrain, resulting in massive dilatation of the lateral, third, and fourth ventricles and hydrocephalus. Histologic examination revealed two distinct features: undifferentiated, primitive, polygonal to fusiform cells with typical morphologic characteristics of medulloblastoma and interspersed areas containing myelinated axons and cells with glial and neuronal differentiation. Immunohistochemical examination confirmed the presence of primitive neuroepithelium and cells with glial and neuronal differentiation.

Animals↗
PubMed1998

Photoreceptor cell death by apoptosis in dogs with sudden acquired retinal degeneration syndrome.

OBJECTIVE: To examine the role of apoptosis in retinal photoreceptor degeneration in dogs with sudden acquired retinal degeneration syndrome (SARDS). SAMPLE POPULATION: Retinas from 3 dogs with SARDS and from 2 clinically normal adult dogs. PROCEDURE: Apoptosis was identified by in situ end-labeling and observation of characteristic morphologic changes by light microscopy. RESULTS: The degree of photoreceptor degeneration varied with duration of vision loss in SARDS-affected eyes. The retina of all 3 SARDS-affected eyes had numerous (34, 61, and 70) apoptotic nuclei per section that were overwhelmingly located in the outer nuclear layer. Apoptotic nuclei were not detected, or were rare in similarly sized retinal sections from normal dogs. Inflammation was not an important feature of SARDS. CONCLUSIONS: Apoptosis appears to be at least 1 mechanism of photoreceptor cell death in dogs with SARDS. CLINICAL RELEVANCE: Because apoptosis appears to be a final common pathway in many retinal degeneration syndromes, future treatment strategies that control apoptosis in other diseases may be applicable to dogs with SARDS. Halting this pathway may allow some photoreceptors to survive and, perhaps, preserve vision.

Animals↗
PubMed1997

Ultrasound attenuation and backscatter in the liver during prednisone administration.

Ultrasound attenuation and backscatter changes resulting from glucocorticoid administration were investigated in a dog model. Ten beagle dogs were randomized into two groups: five were given 2 mg/kg/day IM injections of prednisone to induce steroid hepatopathy and five served as controls. Histology showed vacuolization in most hepatocytes of treated animals on the third day of treatment, and larger, midzonally distributed vacuoles from day 7 on. An increase in both ultrasonic attenuation and backscatter was observed in treated dogs during in vivo measurements. Pooled data from the two groups suggest that attenuation elevations precede backscatter changes. Attenuation was significantly higher in the treated animals than in the controls by day 7. Both attenuation and backscatter were significantly higher in livers of treated than untreated dogs when measured by direct application of the transducer on the liver following euthanasia. We conclude that attenuation and backscatter coefficients can detect early changes in the liver associated with steroid hepatopathy. This may be a useful model to investigate detection of diffuse liver disease with ultrasound tissue characterization.

Animals↗
PubMed1997

Exercise enhances creativity independently of mood.

OBJECTIVES: It has been widely accepted in the literature that various forms of physical exercise, even in a single session, enhance positive mood. It has also been shown that physical exercise may sometimes enhance creative thinking, but the evidence is inconclusive. Positive moods can favour creative thinking, but the opposite has also been reported and these relations are unclear. There is a large anecdotal literature suggesting that creative people sometimes use bodily movement to help overcome "blocks". The aim of this study was to establish whether post-exercise creative thinking was attributable to improved mood. METHODS: The responses of 63 participants to an exercise (aerobic workout or aerobic dance) and a "neutral" video watching condition were compared. Mood was measured using an adjective list, and creative thinking was tested by three measures of the Torrance test. RESULTS: Analysis of variance showed a large and significant increase in positive mood after exercise (P < 0.001) and a significant decrease in positive mood after video watching (P < 0.001). A significant increase between the creative thinking scores of the two conditions was found on the flexibility (variety of responses) measure (P < 0.05). A multifactorial analysis of all data failed to show a significant covariance of creative thinking with the two measures of mood (P > 0.05). CONCLUSIONS: These results suggest that mood and creativity were improved by physical exercise independently of each other.

Adult↗
PubMed1997

Anal leiomyoma in a Holstein heifer.

A 2-year-old heifer was presented with masses on her anus that were interfering with cervical manipulation during embryo flushing. The masses had broad stalks attached within the anal sphinchter. Recovery was without incident after surgical resection. No recurrence of the masses had occurred 3 months later. Histologic diagnosis was benign leiomyoma.

Anal Canal↗
PubMed1996

Nephron sparing by partial median nephrectomy for treatment of renal hemangioma in a dog.

A 6-year-old neutered male Golden Retriever was admitted for evaluation of intermittent hematuria of 2 months' duration. A 3-cm heterogeneous mass causing distortion of the caudomedial aspect of the left kidney was detected via ultrasonography. Histologic examination of a renal tissue sample obtained by ultrasound-guided biopsy revealed a telangiectatic vascular plexus of unknown origin. Low glomerular filtration rate was identified by a modified exogenous creatinine clearance test. Excretory urography revealed a filling defect in the medial aspect of the caudal pole of the kidney, near the hilus. Because total renal function was low, a decision was made to perform nephron-sparing surgery involving resection of centrally located renal parenchymal and pelvic tissue by en bloc resection in the median plane, instead of radical nephrectomy. After surgery, the hematuria resolved and further decrease in renal function was not evident. Nephron-sparing surgery is a viable option for dogs with compromised renal function when there is concern that radical nephrectomy may precipitate uremia.

Animals↗
PubMed1996

Measurement of acoustic backscatter and attenuation in the liver of dogs with experimentally induced steroid hepatopathy.

OBJECTIVE: To determine the usefulness of a new method of measuring acoustic backscatter and attenuation in the liver of dogs with experimental steroid-induced hepatopathy. ANIMALS: 10 clinically normal dogs. PROCEDURE: Steroid hepatopathy was induced by daily injections of prednisone (2 mg/kg of body weight, IM). Dogs were evaluated histologically and were sonographically imaged on days 0, 3, 7, 10, and 14. Acoustic backscatter and attenuation were measured from in vivo images of dogs, using a video signal method, and compared with results obtained from analysis of the unprocessed radio frequency signal. RESULTS: Histologic evaluation revealed midzonal, predominantly water-filled vacuoles in hepatocytes by day 7, which persisted for the remainder of the study and significantly (P = 0.0001) increased liver weight on day 14. Attenuation and backscatter increased during the experimental period. Mean effective attenuation difference was higher (P = 0.015) in the liver imaged through a left paraxyphoid window in experimental dogs by day 3. Significantly (P < 0.05) greater attenuation persisted in the liver of experimental dogs throughout the experimental period. Mean backscatter ratio was significantly increased (P = 0.02) by day 10. Uncorrected pixel intensity of the liver in 2 experimental dogs was approximately equal to that of the spleen on day 10 and greater than that of the spleen on day 14. CONCLUSION: Administration of prednisone to dogs results in increased acoustic backscatter and attenuation in the liver. CLINICAL RELEVANCE: The video signal method is a sensitive technique for detecting subtle acoustic changes in the liver of dogs.

Animals↗
PubMed1995

Erythropoietin response in subjects with obstructive sleep apnea.

We measured nocturnal plasma erythropoietin concentration (EPO) in eight subjects with obstructive sleep apnea syndrome (OSAS) and eight healthy overweight subjects while they were undergoing nocturnal polysomnography. We also measured EPO (radioimmunoassay) after 120 min of exposure to 10.5% O2. The subjects with OSAS had a respiratory disturbance index (RDI) of 50.8 +/- 41.9 and a maximal O2 desaturation of 65 +/- 13.3%, and they spent 104.5 +/- 89.3 min out of a total sleep time of 356 +/- 54 min below 90% oxygen saturation (T90). Nocturnal EPO concentrations were normal and did not differ between the two groups. We found no correlation between the T90, T80, or RDI and either the mean or maximal EPO concentrations. After the exposure to 10.5% oxygen, during which oxygen saturations were between 80 and 85%, the healthy subjects and those with OSAS developed increases in EPO of 34 and 49%, respectively, 240 min after the initiation of exposure (p < 0.05). We conclude that the nocturnal hypoxemia occurring in these subjects with OSAS may not have been sufficiently severe to stimulate an increased EPO production. The lack of EPO response was not due to down-regulation of EPO production.

Adaptation, Physiological↗
PubMed1995

Primary gastrointestinal lymphosarcoma with epitheliotropism in three Shar-pei and one boxer dog.

Three male Shar-pei dogs and one female spayed Boxer dog ranging in age from 4 years, 4 months to 7 years, 8 months had 4-7-week histories of diarrhea, progressive anorexia, weight loss, and vomiting. The dogs were depressed, lethargic, and hypoalbuminemic, with losses of 23-39% of body weight. Endoscopic examination revealed gastric ulceration with areas of mucosal hyperemia and pallor. Small nodules with occasional central depressions were present in three dogs. Gastric and proximal duodenal mucosal biopsies showed neoplastic lymphocytes infiltrating the lamina propria, with invasion of the superficial and glandular epithelial basement membrane. Immunohistochemical evaluation of two dogs was negative for anti-canine IgG and positive for anti-CD3. Necropsy of the Boxer and two Shar-peis confirmed epitheliotropic gastric and small intestinal lymphoma in all three dogs, with mesenteric lymph node and hepatic involvement in two and one dog, respectively.

Animals↗
PubMed1994

Pulmonary and critical care medicine.

Although it is still unknown how much CPAP use is sufficient to prevent daytime hypersomnolence in obstructive sleep apnea syndrome, sleeping without CPAP for one night reversed the beneficial effects of 1 month of CPAP use. The assessment of tissue pH is relatively easy in hollow organs by means of tonometry.

Critical Care↗
PubMed1994

Administration of anti-granulocyte mAb RB6-8C5 impairs the resistance of mice to Listeria monocytogenes infection.

Mice injected i.p. with RB6-8C5 mAb experienced a profound depletion of neutrophils in the bloodstream and spleen and significant impairment of their resistance to experimental infection with Listeria monocytogenes. Control mice survived i.v. inoculation with 5 x 10(4) L. monocytogenes; whereas, most RB6-8C5 mAb-treated mice inoculated i.v. with as few as 10 L. monocytogenes died within 6 days. RB6-8C5 mAb treatment was particularly deleterious when given within the first 24 h after i.v. inoculation with L. monocytogenes; however, some adverse effect was observed even when administration was delayed until 3 or 5 days after bacterial inoculation. Histopathologic examination of the livers of RB6-8C5 mAb-treated mice revealed necrotic foci that were characterized by few inflammatory cells and massive numbers of Gram-positive bacteria within hepatocytes. Additional evidence that the effects of RB6-8C5 mAb administration were chiefly due to neutrophil depletion include: 1) the effects of RB6-8C5 mAb treatment occurred more rapidly than what is generally seen in mice treated with anti-T cell mAbs, 2) similar results were observed with normal and scid mice, 3) RB6-8C5 mAb administration did not diminish delayed-type hypersensitivity nor the ability of spleen cells from immunized mice to transfer resistance, and 4) natural killer cell activity was unaffected by RB6-8C5 mAb administration. The results of this study provide additional evidence in support of the importance of neutrophils in the early stage of innate resistance to murine listeriosis.

Animals↗