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Biomedical subjects

M McGowan

Publications and source records attributed to M McGowan.

9 recordsLinked to original sources
PubMed1991

Complementary identification in schizophrenia.

Children with schizophrenia turn away from the outside world at an early age because they cannot decode the rhythmic patterns in their parents' voices. These children are unable to separate themselves from their parents as they grow up, and as a result, are unable to develop a sense of self. The schizophrenic child develops complementary behavior to counterbalance the parent's attitudes--that is, if a father acts in a dominant fashion 90% of the time, the child will be submissive in 90% of his/her interpersonal relationships. By working with separation techniques, the nurse therapist can help the client develop a more normalized self-view.

Humans↗
PubMed1990

Characterization of extracellular phospholipase A2 (PLA2) activity in fluid and peritoneal cells from casein-treated rats.

Extracellular phospholipase A2 activity (PLA2) found in the fluid and cells of the peritoneal cavity of rats injected with casein is described. PLA2 activities from both the fluid and cells require Ca2+ and have pH optima of 7. Acid-extraction increased PLA2 activity in the polymorphonuclear leukocyte (PMN) homogenates 20-fold but not the PLA2 activity in the extracellular fluid. Acid extraction also increased the sensitivity of the PLA2 activities to standard inhibitors. Since the PLA2 activities described in this model have characteristics similar to other inflammatory PLA2s, including human synovial fluid PLA2, casein stimulation should prove useful for testing potential inhibitors.

Animals↗
PubMed1990

Congenital spinal stenosis in beef calves in western Canada.

Nineteen calves with a clinical history of posterior weakness or ataxia were examined at necropsy. Dorsoventral narrowing of the vertebral canal and myelopathy were found in the thoracic and lumbar areas of the spinal cord; vertebral metaphyseal growth plates had focal areas of premature closure. Malformation of the cranial base and hydrocephalus were also observed. Shortening of long bones and malformation of long bone epiphyses were prominent findings and were associated with focal premature closure of metaphyseal growth plates. The cause of these lesions is unknown; possible causes, including a maternal deficiency of manganese, are discussed.

Animals↗
PubMed1990

Hepatic copper concentrations in purebred and mixed-breed dogs.

Histomorphologic, histochemical, and atomic absorption analysis studies were performed on liver tissue from 623 clinically normal purebred and mixed-breed dogs to assess the range of hepatic copper concentrations, the histologic distribution of copper, and the histomorphologic changes associated with the various copper concentrations that were found. Atomic absorption analysis revealed a continuous numerical spectrum ranging from less than 100 parts per million on a dry weight basis (ppm dw) to more than 2,000. No decisive numerical criterion was found that could be used to separate normal from abnormal copper concentrations because of this continuous array. The threshold for histochemical demonstration of copper-containing granules using rhodanine or rubeanic acid staining was 400 ppm dw. At this concentration the copper-containing granules were located in the centrilobular hepatocytes (zone 3 of Rappaport). Copper-containing granules were found in the midzonal and periportal hepatocytes (zones 2 and 1 of Rappaport) in livers with 1,000 ppm dw and higher copper concentrations. The majority of the 623 livers were normal histomorphologically. Multifocal hepatitis characterized by mixed inflammatory cell accumulation and centrilobular distribution was found to be associated with copper concentrations in the range of 2,000 ppm dw or higher. An appropriate upper limit for normal hepatic copper concentration in the dog was not determined based on the present study.

Animals↗
PubMed1989

The effect of immunomodulating drugs on adjuvant-induced arthritis in Lewis rats.

The purpose of this study was to investigate the effects of cyclosporine A (CSA) and methotrexate (MTX) as potential immunomodulators in a nonestablished adjuvant arthritis (AA) model. Non-injected hind paw volumes were reduced when AA rats were treated for 18 days with CSA (100% at 10 mg/kg) or MTX (100% at 0.1 mg/kg). Body weights of drug treated AA rats were increased above untreated AA rats and were similar to non-arthritic controls. AA rats show elevated T helper (W3/25+)/T suppressor (OX 8+) cell ratios (2.0 vs. 3.1, p less than 0.01). The immunomodulators tested all returned these elevated ratios to control non-arthritic levels. Similarly, these drugs returned the reduced mitogen responses and elevated blood granulocyte numbers toward normal non-arthritic control values.

Animals↗
PubMed1989

Phospholipase A2 (PLA2) activity in rabbit chondrocytes.

The effects of recombinant interleukin-1 beta (rIL-1 beta), recombinant tumor necrosis factor (rTNF alpha) and two growth factors, basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) on PLA2 activity and prostaglandin E2 (PGE2) release were investigated using rabbit chondrocytes. Cellular PLA2 activity increased 2-10 x above controls in the presence of 8 x 10(-12) M (5 U) rIL-1 beta or 5 x 10(-9) M rTNF alpha after 20 hr incubation. PLA2 activity remained constant with 1-50 ng/ml of either growth factor. PGE2 release significantly increased (p less than 0.05) when the chondrocytes were incubated with rIL-1 beta, bFGF and EGF alone, but not with rTNF alpha above. These data suggest PLA2 activity and PGE2 release are not coordinately regulated in rabbit chondrocytes.

Animals↗
PubMed1987

Tooth enamel structure in the koala, Phascolarctos cinereus: some functional interpretations.

The purpose of this study is to determine whether the structural organization of Pattern 2 marsupial enamel in the Koala is disposed to resist wear on the sectorial crests of the molar teeth. The orientation of wear on the crests is uniformly delineated by parallel scratches on their polished surfaces. Twin blades, a leading and a trailing edge of enamel are formed on each crest by wear into dentine on which the differential wear at enamel to dentine interfaces indicates that the direction of wear is labial to lingual. 96 leading and trailing edges from 12 koala molars were examined by light and scanning electron microscopy as ground sections, polished and etched surfaces or polished and etched whole mount preparations sputter coated with gold. The results showed that the leading and trailing enamel edges are different in their thicknesses, and in the course of their rods. The rods in the thinner leading edge are angled at 25 degrees to the long axis of the tooth and cross the worn surface at 60-70 degrees. Trailing rods run at 5 degrees to the long axis to cross the worn surface at 90 degrees. The inter-rod sheets run parallel to the wear striations and thus hold the rods in palisades angled in the leading edge particularly to resist the vector of the occlusal forces in the direction of wear. Crystals in the rods emerge roughly perpendicular onto the worn surface which makes them more resistant to abrasion than those in the inter-rod substance which lie parallel to the worn surface and are more readily removed. Koala enamel on the sectorial crests is thus a simple Pattern 2 rod packing pattern but the angles of the rods and the alignment of the inter-rod substance appear to be adapted to resist occlusal forces and abrasion.

Animals↗
PubMed1985

Hippocampal stimulation disrupts spatial working memory even 8 h after acquisition.

The present experiment used hippocampal stimulation to determine the temporal gradient of consolidation of spatial working memory. Rats were trained to perform a spatial working memory task on a radial maze with 12 arms. Each rat went to the ends of 6 arms to obtain a food reward. After 8 h, the rat chose among all the arms to find the ones not previously chosen (and consequently still having food). During some test sessions, the hippocampus was stimulated electrically either at a current level just high enough to produce an electrophysiological seizure, or at a current level below this seizure threshold. Stimulation occurred at one of five intervals (0 to 8 h) following the completion of the first six choices. During other test sessions, the hippocampus was not stimulated. After seizure stimulation, the number of retroactive errors (returning to arms chosen prior to stimulation) increased at all delay intervals; the number of proactive errors (returning to arms chosen after stimulation) increased only with the delay of 8 h. Subthreshold stimulation had no influence on either type of error. These results indicate that normal hippocampal function is required for the maintenance of spatial information in working memory, and that the time course of consolidation of this information is significantly greater than that seen in other types of memory, or consolidation may not take place at all.

Animals↗