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Biomedical subjects

J A Bennett

Publications and source records attributed to J A Bennett.

At least 109 records · Page 6Linked to original sources

Accurate prediction of experimental cancer chemosensitivity using the subrenal capsule xenograft assay.

The chemosensitivity of a murine lung carcinoma grown as a xenograft under the kidney capsule of a rat was compared to the chemosensitivity of this tumor grown as a spontaneous metastasis in its syngeneic host. The chemosensitivity of the tumor to intravenously or subcutaneously administered drugs determined in the short-term xenograft assay accurately predicted the chemosensitivity of this tumor when it was growing as a spontaneous micrometastasis in its syngeneic host, indicating that in both situations the pharmacological determinants of tumor response to anticancer drugs were similar. These results suggest that tumors growing as xenografts under the kidney capsule accurately reflect the responsiveness of these tumors to chemotherapy and support further investigation of the xenograft subrenal capsule assay as a model that may be useful in predicting effective chemotherapy for human tumors.

Animals↗

Use of an electronic stimulator for the treatment of dry mouth.

This paper presents an innovative approach to the treatment of xerostomia through normal physiologic mechanisms with a device that provides electrical stimulation to the oral and pharyngeal afferent nervous system; the result is a reflex volley of efferent impulses to the salivary glands, causing salivation. The device has been successful in treating xerostomic patients regardless of the etiology of their dry mouths.

Animals↗

The location and characteristics of sympathetic preganglionic neurones in the lower thoracic spinal cord of dog and cat.

The retrograde transport of horseradish peroxidase from a white ramus communicans has been used to define the precise segmental location of sympathetic preganglionic cell bodies in the spinal cord of the cat and dog. All labelled cells were found ipsilaterally and were confined to the spinal cord segment from which the ramus originated. Most lay in the intermediolateral cell column and the immediately adjacent white matter, though others were scattered in more medial areas of the grey matter. We suggest that the observed distribution of sympathetic preganglionic neurones, the orientation of their processes and the paths taken by their axons are a direct result of cell migration during the embryological development of the spinal cord.

Animals↗

Evaluation of cyclosporine-treated mice as hosts for growing and testing the chemosensitivity of first-transplant-generation human tumor xenografts implanted under the kidney capsule.

Freshly resected human tumors were grown as xenografts under the kidney capsules of conventional mice immunosuppressed by daily treatment with cyclosporine A (CsA; 60 mg/kg/day, sc). Tumor persistence and growth in CsA-treated mice were comparable to those found in nude mice. Lower doses or less aggressive schedules of CsA resulted in xenograft rejection. CsA (60 mg/kg/day, sc) treatment of mice was toxic but not lethal. It resulted in a 20% decrease in water consumption, a 10% loss in body weight, and significant reductions in thymus, kidney, and liver weights. Therapeutic doses of cancer chemotherapeutic agents were tolerated by CsA-treated mice, but 10% lethal doses were lethal in 100% of the mice. These results indicate that CsA-treated mice would be an economic alternative to nude mice for growing human tumor xenografts and for testing their chemosensitivity, with the caveat that the dose-limiting toxicity of cancer chemotherapeutic agents will be reached at lower doses in CsA-treated mice.

Animals↗

Neurones in the brain stem of the cat excited by vagal afferent fibres from the heart and lungs.

Extracellular recordings were made from 164 neurones in the nucleus tractus solitarius and dorsal motor vagal nucleus of the chloralose-anaesthetized cat. 139 neurones were excited synaptically and 25 non-synaptically by electrical stimulation of cardiac and pulmonary vagal branches. Synaptically excited neurones fall into two populations, one activated solely by myelinated afferent fibres and a second activated solely by non-myelinated afferent fibres. 94 neurones were synaptically excited by afferent fibres in a single vagal branch while 45 were excited by stimulation of two or three branches. Neurones responding to volleys in myelinated afferent fibres were located in both medial and lateral regions of the nucleus tractus solitarius whilst those excited by non-myelinated afferent fibres were restricted to the medial region. Consistent differences in the locations of neurones excited by stimulation of either cardiac or pulmonary or by single or several branches could not be distinguished.

Action Potentials↗

Cyclosporine-induced gingival hyperplasia: case report and literature review.

A case of gingival hyperplasia was related to the use of cyclosporine for the prevention of renal allograft rejection. With the increasing use of cyclosporine to protect allograft organ transplants, general dentists and dental specialists increasingly will be called on to diagnose and treat gingival hyperplasia.

Adult↗

HTLV-III AIDS link.

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Acquired Immunodeficiency Syndrome↗

A new co-axial breathing system. A combination of the benefits of Mapleson A, D and E systems.

A new, simple, versatile co-axial breathing system combining the features of Mapleson A, D and E type systems is described. The change from an A system to a D/E system is effected by a single switch and without reversal of the gas flow. Fresh gas flows in the order of 70 ml/kg/min are required for both spontaneous ventilation in the Mapleson A mode and controlled ventilation in the Mapleson D mode. The co-axial configuration offers the advantages of a single, lightweight breathing system with easy scavenging of anaesthetic gases, while the ability to switch between the A and D or E configurations offers the economic advantages of low fresh gas flows and the need for a single anaesthetic breathing system for all situations.

Anesthesia, Inhalation↗

Evaluation of growth and histology of human tumor xenografts implanted under the renal capsule of immunocompetent and immunodeficient mice.

Fresh surgical explants of human carcinomas were implanted as first transplant generation xenografts under the kidney capsule of mice. Immunocompetent and immune-deficient mice were compared for their ability to support the persistence and growth of these xenografts. Consistent growth of tumor xenografts could not be demonstrated following implantation under the kidney capsule of immunocompetent mice. Immunological infiltration and rejection of the xenografts began 3 days postimplantation, and tumors were largely eliminated from the subcapsular space by 6 days postimplantation. In contrast human tumors consistently grew under the kidney capsule of nude mice. Significant growth became apparent by 9 days postimplantation with most human carcinomas and continued thereafter. Growth was always accompanied by neovascularization of tumor xenografts which was visible by examination of tumor-bearing kidneys under a dissecting microscope (X 6). There was no histological evidence of immunological interference with the persistence and growth of xenografts in nude mice. Thymectomized, irradiated, bone marrow-reconstituted conventional mice, as well as conventional mice, treated daily with 60 mg of cyclosporine A/kg were comparable to nude mice as hosts which supported the long-term persistence and growth of subrenal capsule implants of human tumors. Such mice could provide an alternative to nude mice as hosts in which chemosensitivity assays could be carried out against growing human tumors at a considerable saving in cost and convenience.

Animals↗

Combined thioridazine and desipramine: early antidepressant response.

The authors examined the effect of combined thioridazine (THI) and desipramine (DMI) for an early antidepressant response in 14 patients with a DSM III diagnosis of major depressive disorder with melancholia. All 14 patients received a constant dose of 200 mg DMI/day for 21 days while 7 patients received 100 mg THI/day for only the first 7 days. A significantly greater improvement from baseline Hamilton Depression Scale (HDS) scores occurred during the first 7 days in patients receiving both drugs. Possible mechanisms for this early antidepressant action are discussed.

Adult↗

Oral surgeons.

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Emergency Medical Services↗

Differences in biological activity among batches of lyophilized tice Bacillus Calmette-Guérin and their association with clinical course in Stage I lung cancer.

Various measures of biological activity were studied in batches of lyophilized Tice Bacillus Calmette-Guérin (BCG) that have been used intrapleurally as adjuvant therapy in surgically resected Stage I lung cancer patients by our own group, the North American Lung Cancer Study Group, and the Ludwig Lung Cancer Study Group. The biological activities of BCG that were studied were: (a) inhibition of solid tumor growth in mice following s.c. inoculation of BCG admixed with methylcholanthrene-induced fibrosarcoma cells (MC 43); (b) protection against tumor colonization of lungs and prolongation of survival in mice pretreated intrapleurally with BCG and later inoculated i.v. with a lethal dose of MC 43 tumor cells; and (c) growth properties in vitro, including a determination of the relative amounts of growing and nongrowing material and the sensitivity of growing material to inhibition by isoniazid. Significant differences in biological activity among batches of BCG were found. Some batches of BCG protected mice against circulating tumor cells, while others did not. Batches of BCG which protected mice against circulating tumor cells were found to have greater sensitivity to isoniazid and higher viability than batches which did not elicit this antitumor activity. There were also trends of some batches of BCG outperforming others in the clinic. Cumulative disease-free interval of patients was longer with batches which protected mice against circulating tumor cells than with batches which did not protect mice against circulating tumor cells. The results of this study suggest that preclinical testing of BCG for antitumor activity may improve the efficacy of this agent in future clinical trials.

Animals↗