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Biomedical subjects

R H Fleming

Publications and source records attributed to R H Fleming.

28 records · Page 2Linked to original sources
PubMed1994

Bone structure and breaking strength in laying hens housed in different husbandry systems.

1. Bone structure and breaking strength were measured in hens that had been housed throughout a laying year in battery cages or in Perchery, Naturel or Litter and Wire husbandry systems. 2. Battery caged hens had the poorest bones, as assessed by measurements of cancellous bone volume, radiographic density, cortical thickness and three-point breaking strength. 3. Humeri from birds in the Litter and Wire system were less dense radiographically and weaker than those from Perchery or Naturel birds but leg bone characteristics were similar with these three systems. 4. There were no differences in bone characteristics between birds in Perchery and Naturel systems. 5. There were strong correlations between radiographic densities and strengths of contralateral humeri and tibiae over all husbandry systems. Humerus structural and strength characteristics may be the best criteria of osteoporosis in hens. 6. It is concluded that the extent of movement allowed by different husbandry systems affects structural bone loss and bone strength in laying hens. 7. It is further concluded that the breaking strength of a hen's bone is closely related to morphometric measures and radiographic density of its structural components.

Analysis of Variance↗
PubMed1994

Small intestinal sarcoidosis with massive hemorrhage: report of a case.

Sarcoidosis of the small intestine is a rarely described complication of systemic sarcoidosis. Although bleeding from sarcoidosis of the esophagus, stomach, and colon has been reported, massive bleeding from this condition in the small intestine has not been previously described. We present here the first case of hemorrhage from a jejunal sarcoid lesion that was unsuspected and undiagnosed until laparotomy with resection was performed. As with most pathologic conditions of the small intestine, preoperative diagnosis is difficult. Furthermore, the refractory nature of bleeding from this lesion made resection necessary in this patient, suggesting the need for similar therapy in other affected patients.

Adult↗
PubMed1988

Characterization of cells comprising murine thymocyte multicellular complexes.

Characterization of complexes between thymocytes and thymic stromal cells was facilitated in the present study by demonstrating that complexes would reform if cells were incubated for 1.5 to 2 h in vitro at ambient temperature. Several immunologic approaches were used to determine the phenotype of complexed cells. Bound T cells were 97% double-positive (CD4 and CD8), 3% double-negative and greater than 99% CD3 positive by using immunoperoxidase immunohistology on cytospins. Five percent expressed the TCR beta-chain and 1 to 2% were IL-2R positive. The percentages were the same whether complexes were preformed in vivo or formed in vitro. Despite the apparent absence of single positive cells in complexes, when isolated CD4 or CD8 positive cells were tested for their ability to bind to adherent thymic macrophages, each subpopulation contained some cells which were capable of complex formation. When thymocytes were fractionated by density, steroid sensitivity or peanut agglutinin positivity then allowed to form complexes, cells with an immature phenotype had a greater propensity for complex formation. Central stromal cells all were class II MHC gene product (I-A and I-E) positive, expressed macrophage-associated Ag (B23.1 and MAC-1), were negative for cytokeratin but positive for vimentin, were reactive with a polyclonal antimacrophage serum, but did not express dendritic cell Ag (33D1). The data demonstrate that immature thymocytes bind exclusively to class II MHC gene product positive thymic macrophages. This binding step may play a role in the acquisition of T cell function in the thymus.

Animals↗
PubMed1986

In vitro measurement and computer modelling of the diffusion of antibiotic in bone cement.

The diffusion coefficient for a particular antibiotic (benzyl penicillin) in various types of bone cement has been calculated from direct measurement of the passage of radio-labelled penicillin through thin sections of cement at intervals over a period of 90 days, assuming the transport processes to be Fickian. Since the concentration gradient across the test sample is not uniform in the earlier stages of the experiment, a finite-difference approximation to the diffusion equation was used to take account of the transient behaviour in determining the coefficient. This method of analysis may also be used to predict the release, as a function of time, from the surface of antibiotic-loaded bone cement and from implanted pre-loaded PMMA beads used to provide antibiotic cover following bone or joint surgery. Our computer-generated predictions appear to agree very well with previously published figures arising from in vivo and in vitro studies and we conclude therefore, that Fick's Law accurately describes the process, even when the cement mix is inhomogeneous. We have by this means a reliable method by which the diffusion coefficients for various combinations of cement, antibiotic and other additives may be retrospectively determined and compared.

Anti-Bacterial Agents↗
PubMed1986

The volume of distribution of ceftazidime and albumin in normal, immature and infected bone.

The penetration of ceftazidime into bone was determined by measuring the volume of distribution of 14C-ceftazidime in infected and non-infected bone of adult mongrel dogs. The volume of distribution in non-infected cortical bone was 0.114 +/- 0.011 l/kg (mean +/- S.E.M.) and increased significantly in non-infected immature callus to 0.484 +/- 0.13 l/kg (P less than 0.05). In the presence of infection, the volume of distribution in non-infected cortical bone was 0.144 +/- 0.05 l/kg, and significantly higher in infected reactive cortical bone, 0.453 +/- 0.07 (P less than 0.05). We conclude that ceftazidime penetrates infected and non-infected bone and that this penetration is greater into immature bone.

Animals↗
PubMed1985

Post Vietnam syndrome: neurosis or sociosis?

Recently released figures from the Veterans Administration on the number of Vietnam veterans who have been granted service connection in their claims for post-traumatic stress disorder appear to be astonishingly low, given the publicity that the media and mental health professionals have placed on this diagnosis in recent years. As of the summer of 1984, only slightly more than 7,000 Vietnam veteran cases had been approved by VA rating boards. A conservative popular estimate is that half a million Vietnam veterans are alleged to suffer from this neurosis, which is largely attributable to combat-related experiences. This gross discrepancy raises many serious questions about the appropriate use of the clinical diagnosis of post-traumatic stress disorder. The point of contention is not the legitimacy of the diagnosis, but the abuse and misuse of the term for personal or political purposes to explain the dilemma of the Vietnam veteran in contemporary America. The traditional psychodynamic content of clinical psychology needs to be integrated with an analysis of the impact of social, political, historical, economic, and philosophical forces on individual and group dynamics. The objective of this paper is to examine those forces, the social and historical conditions in particular, which have contributed to the origin, development, and prolongation of readjustment difficulties for Vietnam veterans.

Adult↗
PubMed1984

The early effects of sympathectomy on bone blood flow.

Several laboratories, including our own, have investigated the physiology of bone blood flow by perfusion of the tibia via the nutrient artery. Any damage caused to the nerve supply by cannulation of the artery might affect the results. The possible effect of such damage was investigated by measuring blood flow to the dog tibia using a microsphere technique, before and after sympathectomy. No effect was found and the tibial nutrient artery is therefore a suitable vessel for perfusion when estimating nutrient exchange in bone.

Animals↗
PubMed1977

Reversible corticospinal tract disease due to hyperthyroidism.

Corticospinal tract malfunction was seen in a patient with Graves' disease. The absence of intracranial and intraspinal lesions likely to cause the neurologic manifestations and their regression after control of thyroid dysfunction favors a cause-effect relationship. We review and compare similar cases previously reported and discuss the mechanisms.

Adult↗
PubMedDate not supplied

Medullary bone and humeral breaking strength in laying hens.

To test the hypothesis that large amounts of medullary bone in the humeral diaphysis may increase breaking strength, various parameters of bone quality and quantity were examined in two large flocks of hens near end of lay. We conclude that the amount of medullary bone in the humerus of hens during the laying period influences bone strength. This medullary bone may not have any intrinsic strength, but may act by contributing to the fracture resistance of the surrounding cortical bone. Using a quantitative, low dose, radiographic technique, we can predict, from early in the laying period, those birds which will develop large amounts of medullary bone in their humeri by the end of the laying period. The formation of medullary bone in the humeral diaphysis is not at the expense of the surrounding radiographed cortical bone.

Animals↗