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Biomedical subjects

D R Schneider

Publications and source records attributed to D R Schneider.

At least 19 recordsLinked to original sources
PubMed1985

Immunoblastic sarcoma of T- and B-cell types: morphologic description and comparison.

Immunoblastic sarcoma (IBS) is a large cell lymphoma conceptually related to transformed T and B lymphocytes of the extrafollicular compartment of the immune system (immunoblasts). This light microscopic study of a series of 47 immunologically defined cases of IBS was undertaken in an attempt to define more precisely the morphologic features of the T- and B-cell subtypes. A remarkable morphologic spectrum characterized T-IBS (31 cases), which could be divided into two main groups: 1) tumors composed of varying mixtures of small, medium-sized, and large transformed cells; and 2) tumors with more homogeneous populations of medium-sized or large transformed cells. These cells, in all sizes, generally had abundant pale-staining cytoplasm, delicate nuclear membranes, finely dispersed chromatin, and one to several, small or medium-sized, prominent nucleoli. A distinctive background of small, irregular lymphocytes was frequently present. Plasmacytoid differentiation, seen most consistently as amphophilic staining of the cytoplasm, generally characterized B-IBS (16 cases). B-IBS similarly showed a morphologic spectrum that occurred in two main forms: 1) tumors consisting of a spectrum of transformed cells, with the smaller cells often showing the most striking plasmacytoid differentiation; and 2) tumors consisting predominantly of medium-sized to large transformed cells with varying degrees of plasmacytoid differentiation. With this constellation of features, all but two cases of T-IBS and one case of B-IBS were morphologically distinguishable.

Adolescent↗
PubMed1985

Alpha 1-antitrypsin and lysozyme in fibrous papules and angiofibromas.

The large stellate and polygonal cells observed in eleven fibrous papules and two angiofibromas were examined immunohistochemically for alpha 1-antitrypsin and lysozyme. The positive findings suggest that these cells are related to histiocytes rather than nevomelanocytes.

Histiocytes↗
PubMed1985

Myelodysplasia in the acquired immune deficiency syndrome.

Certain new hematologic findings in eight homosexual or bisexual patients with the acquired immune deficiency syndrome (AIDS) are presented. All eight patients manifested a normochromic, normocytic anemia, and six of eight had granulocytopenia during their hospitalization. The other two had low-normal granulocyte counts. Bone marrow examination showed normocellular or hypercellular marrows with increased myeloid: erythroid ratios and increased numbers of megakaryocytes. All patients had abnormalities in maturation of all cell lines, most prominent in the granulocytic series. This constellation of features is similar to the findings in the myelodysplastic syndromes (preleukemia). The authors suggest that myelodysplasia in patients with AIDS results in ineffective hematopoiesis and contributes to the peripheral blood cytopenias found in these patients. Myelodysplasia could be a direct or indirect effect of human T-lymphotropic retrovirus-III (HTLV-III).

Acquired Immunodeficiency Syndrome↗
PubMed1984

Ethanol effects on harmaline-induced tremor and increase of cerebellar cyclic GMP.

The spectra of pharmacological effects of ethanol and the benzodiazepine show a degree of overlap. Neurophysiological and neurochemical evidence indicates that both ethanol and benzodiazepines facilitate inhibitory neurotransmission mediated by GABA. Diazepam has been reported to inhibit both the tremor and mechanism of cerebellar cyclic GMP caused by harmaline by a neurotransmission in the cerebellum. Because of the similarities between ethanol and benzodiazepines, the effects of ethanol on harmaline-induced tremor and increase of cerebellar cyclic GMP were studied. Ethanol inhibited harmaline-induced tremor at doses as low as 0.1 g/kg. At this low dose, however, a dissociation between inhibition of harmaline tremor and inhibition of the harmaline-induced increase of cerebellar cyclic GMP was observed.

Alkaloids↗
PubMed1982

Development and use of a nonrestraining waveguide chamber for rapid microwave radiation killing of the mouse and neonate rat.

The use of microwave energy for rapid killing of small rodents such as the mouse or rat has become a standard pharmacologic technique since approximately 1975. This method allows investigation of rapidly modulated neurochemical indices, neuromodulatory substances, and some neurotransmitters to be determined at basal concentrations in brain regions and microregions. Previously described devices for use with microwave generators have relied on total body restraining holders in order to properly position rodents and neonates within a closed waveguide during microwave energy exposures. The present information describes two alternate chamber designs which do not require restraint of the rodent. A positioning device is described which must be used with the waveguide chambers. The animal chambers are designed to be used with 2450 MHz energy.

Adenosine Triphosphate↗
PubMed1982

An automated microprocessor-controlled data collection device for use with the Technicon AutoAnalyzer system.

An automated microprocessor-controlled data collection system for use with a Technicon AutoAnalyzer in a research or clinical laboratory is described. The collection system can digitize an analog output from the AutoAnalyzer, perform mathematical operations on this digital data, detect and record peak-trough data, and perform these data acquisition and mathematical data processing operations in parallel. The data collection system can be interfaced to a variety of host computers for further data analysis. The accuracy of the data collection system was tested and compared to existing procedures using an analysis of bovine serum albumin protein. The correlation coefficient for the comparison of the results was 0.99998. Hence, the automated system is as accurate as previous methods, but is considerably faster, more efficient, and, in comparison to existing devices, less expensive.

Analog-Digital Conversion↗
PubMed1982

Purification and characterization of the mucinase of Vibrio cholerae.

Mucinase from Vibrio cholerae strain CA401 was purified by precipitation with ammonium sulfate and chromatography on a column of BioGel P-100 (Bio-Rad Laboratories, Richmond, California). Ovomucinase, intestinal mucinase, and protease appeared as two peaks of slightly different molecular weights, comigrated in nondenaturing polyacrylamide gel electrophoresis, demonstrated similar patterns of inhibition by heavy metals, and were inhibited by antiserum to purified mucinase. Both molecular weight forms exhibited similar properties, which were identical to those of fresh culture supernatants. Specific activity was only slightly increased by purification. Antiserum to mucinase passively protected infant mice from diarrhea due to V. cholerae.

Animals↗
PubMed1982

Effect of pyridines on phenotypic properties of Bordetella pertussis.

Several conditions of growth of Bordetella pertussis cause a reversible phenotypic alteration in properties termed modulation. Growth in medium containing nicotinic acid induces normal (X-mode) cells to change to modulated (C-mode) cells. We examined several pyridines and compounds resembling pyridines for their ability to affect modulation, using envelope protein patterns and serological reactivity as indicators of modulation. We found that 6-chloronicotinic acid and quinaldic acid were more effective modulating stimuli than was nicotinic acid on a molar basis. Both 2-chloronicotinamide and isoniazid interfered with nicotinic acid-induced modulation, and can be called antimodulators. Picolinic acid inhibited growth.

Agglutination Tests↗
PubMed1981

Effect of diesel particulate exposure on adenylate and guanylate cyclase of rat and guinea pig liver and lung.

An examination of the effects of 250 or 1500 micrograms m-3 concentrations of diesel particulate from diesel exhaust on the activity of adenylate or guanylate cyclase was undertaken using liver and lung tissue of rats and guinea pigs. These membrane and cytosolic enzymes were selected to screen for functional or regulatory alterations in these tissues. The studies for adenylate cyclase used the microsomal membrane fraction of each tissue; for guanylate cyclase, the microsomal membrane and supernate fractions were used. Basal and fluoride-stimulated adenylate cyclase activity were measured. Basal and sodium azide-stimulated guanylate cyclase activity were also determined. The basal activity of rat liver adenylate cyclase is generally unchanged throughout 52 weeks of diesel exposure. Stimulated adenylate cyclase shows an age-related decrease for all animal treatments throughout the study. Changes in enzyme activity occurred at 12 weeks and 52 weeks after 1500 micrograms m-3 exposure. Soluble stimulated guinea pig lung guanylate cyclase was first increased (6 weeks) and then decreased (24 weeks) by diesel exposure. At 52 weeks, there was no change. The data suggest the following trends: (1) an increased basal adenylate cyclase in the rat lung; (2) an age-related decrease in adenylate cyclase activity in rat liver, and (3) a biphasic exposure-related response of soluble guanylate cyclase for the guinea pig lung during the first 24 weeks, but no change at 52 weeks. In general, however, these studies suggest that diesel exposure does not substantially alter either of these intracellular regulating enzymes.

Adenylyl Cyclases↗
PubMed1981

Cyclic AMP in female mouse brain is altered by the adrenocorticotropic hormone(4-9) analogue organon 2766.

Cyclic AMP content was determined in 12 brain regions of young adult female mice at 30 min and at 24 h following an intraperitoneal injection of the tri-substituted adrenocorticotropic hormone(4-9) [ACTH(4-9)] analogue Organon 2766 [ORG 2766]. Animals were killed by focused 3.5 kW microwave radiation applied for 350 ms. Unlike previously reported responses in male mice, at 30 min post-injection there were no detectable differences in cyclic AMP content between the placebo and ORG 2766-treated animals. By contrast, 24 h after injection, the content of cyclic AMP was changed significantly in 8 of the 12 brain regions examined: medulla-pons, septal area, thalamus, hypothalamus, hippocampus, olfactory bulb, and parietal and occipital cortices. In most of the regions examined, differences consisted of 50% or greater reductions of tissue cyclic AMP content. The changes were unrelated to the estrus cycle of these animals.

Adrenocorticotropic Hormone↗
PubMed1981

Characterization of Vibrio cholerae protease activities with peptide digest analysis.

A simple method for the analysis of microbial proteases is described that was used to characterize the proteolytic activities of various Vibrio cholerae isolates. This method utilized the unique peptides generated from the degradation of a standard protein by proteases of various specificities. These peptides were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The unique patterns of peptides seen in gels can be used to type proteases according to their relative specificities. Culture supernatants of V. cholerae isolates from a variety of environmental and human sources were analyzed for the presence of a protease previously isolated and characterized in this laboratory from V. cholerae strain CA401. Supernatants from most isolates showing dimethyl casein proteolytic activity exhibited the presence of enzymes similar to the CA401 protease in their peptide digest patterns against bovine serum albumin and in their immunological reactivities. The probable widespread presence of this virulence-associated protease in V. cholerae isolates is discussed.

Bacteriological Techniques↗
PubMed1981

Immunoblastic sarcoma of T-cell versus B-cell origin: I. Clinical features.

Within the Lukes-Collins classification system of malignant lymphoma, a tumor of large transformed lymphocytes, termed immunoblastic sarcoma (IBS), is described. This morphological type would have been included within the "histiocytic" category of Rappaport. Immunoblastic sarcoma may be of B-lymphocytic or T-lymphocytic origin. Since differences or similarities of these two variants have not yet been described, we reviewed the case histories of 35 such patients, all of whom had immunologic marker studies performed. Nineteen patients had T-cell IBS (T-IBS), whereas 16 had B-cell IBS (B-IBS). Median age for both groups was approximately 50 yr. A history of prior immune disorder was found in 31% of B-IBS and 16% of T-IBS cases. Prior lymphoproliferative malignancy was noted in 21% of T-IBS and 13% of B-IBS patients. All T-IBS patients first presented because of lymphadenopathy, whereas 56% of B-IBS cases initially presented because of extranodal disease. Systemic "B" symptoms were common in both. Similarly, most patients had widespread disease (stage III or IV) at diagnosis. Clinically suspected hepatic (p = 0.05) and retroperitoneal node (p = 0.01) involvement were more often found in T-IBS. Forty-one percent of T-IBS patients demonstrated polyclonal hypergammaglobulinemia, a finding seen in no B-IBS patient (p = 0.02). Although not statistically significant because of small numbers of patients, data on therapy and survival suggest that IBS of B-cell type may be successfully treated with aggressive, multiagent chemotherapy, while alternative approaches appear warranted in T-cell disease.

Adult↗
PubMed1979

Cyclic nucleotides in the rat neostriatum: push-pull perfusion studies.

A push-pull perfusion technique was employed for in vivo study of adenosine 3',5'-monophosphate (cAMP) and guanosine 3',5'-monophosphate (cGMP) in the rat caudate nucleus. Addition of dopamine to the perfusion fluid elicited dose-dependent increases of both cAMP and cGMP perfusate concentrations. In separate experiments, it was found that pretreatment of animals with the dopamine antagonist, pimozide, significantly depressed both nucleotide responses to dopamine perfusion over the dose range studied. Mechanistic interpretations of the observations are considered. The push-pull perfusion technique appears to provide an extremely useful means of examining extracellular cyclic nucleotide levels in a discrete brain region, in vivo, under dynamic conditions.

Animals↗
PubMed1979

Cerebral blood flow after treatment with ORG-2766, a potent analog of ACTH 4--9.

Regional cerebral blood flows (rCBF) were measured in conscious, male rats at 10, 30, 60 min and 24 hr after intravenous administration of a potent, behaviorally active analog of ACTH/MSH 4--9 (ORG-2766). Flows in the basal ganglia, hippocampus, septal area and frontal cortex were depressed significantly throughout the 60 min postinjection period. HYpothalamic and parietal flows were depressed at 10 and 30 min, but recovered by 60 min, whereas flow to the cerebellum was depressed between 30 and 60 min postinjection. The least changed and therefore relatively better perfused area throughout the first 60 min period was the occipital cortex. By contrast, at 24 hr, when perfusion of all brain regions had returned to near control levels, flow to the occipital cortex was elevated. During the first hour after treatment with either ORG-2766 or alphaMSH the patterns of regional circulation in the brain were qualitatively the same. The data suggest that ORG-2766 and, probably, alpha MSH trigger serially linked neurophysiologic changes in the brain lasting at least 24 hr, which organize the behavioral actions of this class of peptides on memory and attentional processes.

Adrenocorticotropic Hormone↗
PubMed1979

[Initial reports on experiences in working with special groups in child day care centers].

A decisive condition for advancement at an early stage is the detection of physical damage. In this connection the GDR Ministry of Public Health has published guidelines for the establishment of special groups for infants suffering from physical damage, at ordinary creches (Verfügungen und Mitteilungen 15/1976). In 1976/77 a total of eight special groups with 64 children were set up at creches in the city of Erfurt. The criteria for assigning children to such groups were age and the type/degree of damage, with the aim of having homogeneous group structures. Advancement was through an all-day teaching process, in which parents were involved by giving them guidance, inviting them for discussion evenings and calling on their homes. A description is given of the approach to teaching and methods and planning (written timetables for specific months, weeks and days), all of which are essential in creating adequate educational conditions taking into account individual differences in the level of performance and the prevailing primary damage (e.g. disablement, impaired hearing, marked milieu damage).

Brain Damage, Chronic↗