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Biomedical subjects

H Markowitz

Publications and source records attributed to H Markowitz.

At least 19 recordsLinked to original sources
PubMed1990

Responses of female rhesus macaques to an environmental enrichment apparatus.

Environmental enrichment devices are a potential way to enhance psychological well-being in laboratory animals. The effects of such devices need to be systematically evaluated before they are recommended for widespread use. The purpose of this research was to monitor the behavioural and physiological responses of adult female rhesus macaques to a simple enrichment device. The apparatus consisted of a box attached to the monkey's home cage that contained a radio and a food dispenser, which could be controlled by the monkeys via contact detectors. Radio and food dispenser use were automatically recorded. Whole blood serotonin (WBS), plasma cortisol and abnormal behaviour were measured in 5 monkeys before, during and after a 20-week period in which the monkey's cages were equipped with the device. All monkeys used the device (3 of the 5 subjects earned an average of more than 200 food pellets per day). Mean plasma cortisol and whole blood serotonin did not differ across sampling times, suggesting that the apparatus had no effect on basal stress levels. There was an inverse relationship between apparatus use and cortisol levels in 76% of the samples, but only 3 of 17 coefficients were significant. There was a significant but small negative correlation between apparatus use and self-abusive behaviour. This enrichment device was readily used by adult rhesus monkeys and could be adapted for use in a wide variety of laboratory settings.

Animals↗
PubMed1990

Opposite effects of diabetes on nephrotoxic and ischemic acute tubular necrosis.

The effect of streptozotocin-induced diabetes mellitus on two different models of acute tubular necrosis (ATN), was studied: (i) the nephrotoxic model of HgCl2-induced ATN and (ii) the ischemic model of renal artery clamping for 60 min. Induction of ATN with HgCl2 in normal rats decreased CrCl from 0.67 +/- 0.05 to 0.1 +/- 0.019 ml/min (P less than 0.001) after 24 hr, and it deteriorated further to 0.03 +/- 0.013 ml/min after 48 hr; whereas, in the diabetic rats, HgCl2 decreased CrCl from 0.98 +/- 0.11 only to 0.31 +/- 0.037 ml/min (P less than 0.0001), but CrCl recovered to 0.50 +/- 0.08 ml/min after 48 hr. Bilateral clamping of renal arteries for 60 min in control and diabetic rats extremely decreased CrCl in both groups. Twenty-four hours after clamping, two of nine rats from the diabetic group died, whereas none from the control group died. Forty-eight hours after clamping, all nine rats from the diabetic group died, whereas only two rats from the control group died, and in the four surviving rats CrCl recovered slightly. Our study shows that streptozotocin-induced diabetes could not confer a general protection against ATN. It was protective against a nephrotoxic insult but aggravated the ischemic insult. An attempt to reconcile these discrepant effects is made in the Discussion.

Acute Kidney Injury↗
PubMed1989

Influence of cage size on heart rate and behavior in rhesus monkeys.

We studied 6 singly caged adult female rhesus monkeys to determine whether increased cage size had any effect on behavior or heart rate. Two monkeys at a time were placed in cages 40% larger than their standard cage for 1 week on 2 occasions, using a counter-balanced design. Direct behavioral observations were performed 75 minutes/week on each monkey. Heart rate and general activity were monitored 35 hours/week by a telemetry system. Statistically significant differences were not found in aggressive, submissive, abnormal, or self-abusive behavior, nor in time spent in the front half of the cage, duration of grooming, looking at the observer, or stereotyped or nonstereotyped locomotion. Vocalizations increased the first time in the larger cage, but not the second, and decreased upon the second return to the standard cage. Differences with respect to cage size were not found in heart rate or activity level, although there were significant variations at different times of day. We conclude that modest increases in cage size are unlikely to enrich the environment of singly caged laboratory primates.

Animals↗
PubMed1988

Immunoglobulins and complement in demyelination induced in mice by Theiler's virus.

Intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) produces chronic demyelination and persistent infection in the central nervous system (CNS) of susceptible SJL mice. This series of experiments examined the contribution of humoral immunity and C to myelin destruction. As in multiple sclerosis, mice persistently infected with TMEV had elevated levels of IgG and oligoclonal bands in the cerebrospinal fluid (CSF). Immunoblot studies revealed that even in animals exhibiting profound demyelination, IgG in the serum and CSF was directed primarily at virus antigen rather than at normal myelin components. Inflammatory cells positive for Ig were distributed mainly around blood vessels, but occasionally they infiltrated the spinal cord parenchyma. Rare examples of myelin sheaths positive for IgG were found by immunoelectron microscopy in spinal cord sections from infected mice; the third component of complement (C3) was commonly found in the walls of CNS blood vessels but not on myelin. Neither serum nor CSF IgG from infected mice bound to myelin sheaths or other CNS components in sections of normal syngeneic spinal cord. There were significantly more demyelinating lesions in infected mice depleted of C components with cobra venom factor. These data do not support a humoral autoimmune basis for the CNS demyelination that occurs in association with persistent TMEV infection. However, the humoral immune response directed at TMEV antigens may either limit virus spread or promote virus persistence.

Animals↗
PubMed1986

How lupoid is lupoid hepatitis?

The records of 89 patients with hepatitis B surface antigen, negative severe chronic active hepatitis and antinuclear antibody (ANA) positivity were reviewed to assess the degree of clinical similarity between this disorder and systemic lupus erythematosus (SLE). Although immunologic abnormalities, such as antibodies to native DNA and positive lupus erythematosus cell preparations were common, few patients with ANA positive chronic active hepatitis had clinical features to suggest SLE. The 1971 preliminary criteria and the 1982 revision of the American Rheumatism Association criteria for classification of SLE were 93 and 91% specific, respectively. We conclude that despite laboratory similarities, ANA positive chronic active hepatitis and SLE differ substantially in their clinical presentations.

Adolescent↗
PubMed1985

Improved assay for total hemolytic complement.

Analysis of human serum for total hemolytic complement (CH50) is useful in following the course of patients who have diseases such as lupus nephritis or hypocomplementemic glomerulonephritis. A semi-automated system has been devised that facilitates test performance and reduces cost. An Autoprep dilutor is driven by an Apple IIe microprocessor. Samples are picked up, diluted with buffer, and added to a 96-well flat-bottom Linbro plate in a final volume of 100 microliters. Sensitized sheep RBC (100 microliters) are then added to each well. The plate is incubated at 37 degrees C for 90 min, agitated on a shaker, and then read by a Dynatech MR600 plate reader at 630 nm. The microprocessor converts the reading to percentage hemolysis by utilizing both a buffer blank and a complete hemolysis blank (saponin); these values are applied to the von Krogh equation to yield a CH50 value. Values obtained for normal human serum samples correlate well with those from an established semi-automated method (Technicon) in use in our laboratory.

Complement Fixation Tests↗
PubMed1983

Characterization of human prostatic acid phosphatase radioiodinated by four different procedures.

Prostatic acid phosphatase was labeled by four different iodination procedures: chloramine-T, insoluble or soluble lactoperoxidase, and Bolton-Hunter. Enzyme labeled by the chloramine-T procedure had suboptimal precipitation characteristics in immunoassays, with 36 to 67% of the tracer precipitated in antibody excess. Analysis of the tracer on 7.5% sodium dodecyl sulfate polyacrylamide gel showed that as much as 30% of the radioactivity migrated away from the protein within 6 minutes after the electrophoretic run was begun. The nature of this fast migrating radioiodinated component was not determined. The failure to obtain a tracer labeled by the chloramine-T procedure with optimal immunoprecipitation characteristics led to investigation of alternate radioiodination procedures. Insoluble or soluble lactoperoxidase was less effective than chloramine-T in producing a tracer suitable for radioimmunoassay. In contrast, the Bolton-Hunter procedure produced a tracer that had optimal precipitation characteristics; 88 to 91% of the tracer was precipitated in antibody excess. The tracer was further purified by affinity chromatography to minimize the possibility of other protein contaminants compromising the specificity of a radioimmunoassay for the enzyme.

Acid Phosphatase↗
PubMed1983

Human prostatic acid phosphatase: purification, characterization, and optimization of conditions for radioimmunoassay.

Prostatic acid phosphatase was isolated from benign hypertrophic prostate tissue by ammonium sulfate precipitation and affinity chromatography procedures. The purified enzyme was characterized by two-dimensional gel electrophoresis and shown to have a cluster of protein spots with an apparent molecular weight of 48 000 at pI 5.9 to 6.3 in 9 mol/l urea. The specific activity of the purified enzyme was 723 and 659 U/mg protein with alpha-naphthyl phosphate at 30 degrees C and para-nitrophenyl phosphate at 37 degrees C respectively. An antibody to the purified enzyme was raised in rabbits and used in a radioimmunoassay (RIA). The use of a phosphate buffer, pH 6.6, and iodination of prostatic acid phosphatase (PAP) by the Bolton-Hunter procedure improved the precision of the assay when compared to RIA's using a phosphate buffer, pH 7.0 or 7.3, or PAP iodinated by a chloramine-T procedure. The former RIA displaced 50% of the tracer at 2 micrograms of enzyme per liter of serum. The between-run coefficient of variation for 11 assays ranged from 3.9-7.7% with serum at 1.3 to 5.6 micrograms PAP/l.

Acid Phosphatase↗
PubMed1983

Correlation of thyroid antibodies and cytologic features in suspected autoimmune thyroid disease.

Six hundred forty-three patients with antithyroid antibody results were studied. Antithyroglobulin antibodies were found in 101, and antimicrosomal antibodies were found in 338 patients. Fine-needle aspiration biopsy, performed in 122 patients, yielded a satisfactory aspirate in 108 subjects. Significant antithyroglobulin and antimicrosomal antibody titers were found in 28 of 57 and 149 of 267 patients, respectively. In 65 patients with cytologically proved Hashimoto's thyroiditis, only 15 had positive antithyroglobulin antibody results (11 titers were 1:1,600 or higher), whereas 61 had positive antimicrosomal antibody results (50 titers were 1:1,600 or higher). Thus, cytologic diagnosis of Hashimoto's thyroiditis correlated better with antimicrosomal antibodies than with antithyroglobulin antibody titers. These data suggest that antithyroglobulin antibody determination offers no particular advantage over antimicrosomal antibody titers. In subjects with a clinical diagnosis of Hashimoto's thyroiditis and negative antibody results, fine-needle aspiration biopsy remains useful in establishing the diagnosis.

Antibodies↗
PubMed1983

Isolation and characterization of electrophoretic variants of human prostatic acid phosphatase.

Prostatic acid phosphatase (EC 3.1.3.2) purified from benign hypertrophic prostate tissue was fractionated by preparative slab isoelectric focusing over a pH gradient of 3.16 to 7.16. Twenty-two of 29 fractions contained enzyme activity. We further examined each active fraction by determining the Michaelis-Menten constant and specific activity. The protein concentration used in the latter determination was estimated either spectrophotometrically or immunochemically by three different radioimmunoassays for the enzyme. Determination of specific activities for each fraction directly correlated enzyme activity with an immunochemical determination, which indicated the immunochemical relationships among different molecular species of the enzyme. We found that the Michaelis-Menten constants for the isolated fractions were similar to the Km value for purified, unfractionated enzyme. Most fractions analyzed by each immunoassay had similar specific activities; the few fractions with discrepant specific activities were found at either end of the pH gradient. The similarity in specific activities among the fractions indicates that RIAs involving polyclonal antisera detect all of the electrophoretic variants of the enzyme.

Acid Phosphatase↗
PubMed1982

Giant hypertrophic gastropathy (Ménétrier's disease): pharmacologic effects on protein leakage and mucosal ultrastructure.

Seven patients with giant hypertrophic gastropathy participated in a gastric intubation perfusion study to investigate the route and mechanism of protein leakage associated with this disease. All patients had gastric tight junctions wider than those in healthy controls. Acute administration of propantheline bromide reduced gastric albumin leakage (-50.7%, p less than 0.05) and concurrently decreased width of tight junctions (p less than 0.05) in all patients. Another antisecretory agent, cimetidine, had no consistent effect on protein leakage or on the width of tight junctions. Pentagastrin and bethanechol chloride increased protein loss but had no effect on the width of tight junctions. These results are consistent with the hypothesis that proteins may take a paracellular route via the tight junctions as they traverse the gastric mucosa and that this may have a cholinergic mechanism.

Adult↗
PubMed1980

Antideoxyribonuclease B titers in psoriasis.

Psoriatic patients were examined for serologic evidence of streptococcal infections by using antideoxyribonuclease B (ADB), which has been shown to be a more sensitive screening tool than antistreptolysin O (ASO) for detecting such evidence in other clinical circumstances. Antistreptococcal antibody titers (ASO and ADB) of 71 patients with psoriasis vulgaris, 7 with guttate psoriasis, and 6 with erythrodermic psoriasis were compared with ASO and ADB antibody titers of 25 non-psoriatic dermatologic patients hospitalized at the same time and of an adult group that was used as a control for the test itself. Thirty-six of 71 patients with psoriasis vulgaris had elevated titers of ADB or ASO (41% vs. 15%). Compared with control values the ADB titers were significantly higher in patients with psoriasis vulgaris (P less than 0.02) and patients with guttate psoriasis (P less than 0.05). The ASO titers were significantly higher in patients with psoriasis vulgaris than in controls (P less than 0.04). Within the group with psoriasis vulgaris, ADB titers were significantly higher than ASO titers (P less than 0.01). Among patients with psoriasis vulgaris, histories of sudden flares of psoriasis and early recurrences of psoriasis after previous successful hospital treatment, family histories of psoriasis, and histories of potential streptococcal infections were more frequent in those with elevated antistreptococcal antibodies.

Antibodies, Bacterial↗