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Biomedical subjects

J C Kennedy

Publications and source records attributed to J C Kennedy.

At least 73 records · Page 4Linked to original sources
PubMed1982

Persistent infection with infectious pancreatic necrosis virus mediated by defective-interfering (DI) virus particles in a cell line showing strong interference but little DI replication.

The characteristics of chinook salmon embryo cells persistently infected with infectious pancreatic necrosis virus were consistent with defective-interfering (DI) particle-mediated persistence. All the cells were infected and were slowly releasing virus, but they could be cured of virus in the presence of antiserum. Immunofluorescence showed that the amount of virus antigen in persistently infected cells was low. This fact, coupled with the observation that few DI particles were released by these cells, indicated that DI particles were not replicated to excess in this cell line.

Animals↗
PubMed1982

Some aspects of porphyrin neurotoxicity in vitro.

Using a dissociated primary sensory neuron culture system, it is observed that some naturally occurring porphyrins produce dose-dependent neurotoxicity as measured by neuron death and by inhibition of the neurite outgrowth induced by Nerve Growth Factor (NGF). However, the porphyrin precursor delta-aminolevulinic acid (delta-ALA) is not toxic up to millimolar concentrations within a 30-h time period. Two synthetic porphyrins, tetraphenylporphine sulfonate (TPPS) and hematoporphyrin derivative (HPD), have also been shown to be toxic in vitro. Cultures and cocultures of isolated populations of neurons and glia of central and peripheral nervous system origin may prove advantageous in the study of porphyrin influences on the intact nervous system. This in vitro assay system can complement in vivo paradigms and may be useful for rapid quantitative screening for neurotoxicity of radiation sensitizers including the synthetic porphyrins and other chemotherapeutic agents.

Aminolevulinic Acid↗
PubMed1981

Experimental porphyric neuropathy: a preliminary report.

An experimental model for the study of porphyric neuropathy is presented. Injection of either tetraphenyl-porphinesulfonate (TPPS), hematoporphyrin derivative (HpD), or delta-amino-levulinic acid (ALA) into mice resulted in markedly decreased motor nerve conduction velocity (MNCV). THe MNCV returned to normal within one week following the injection of large doses of ALA, and within three weeks following the injection of close to lethal doses of HpD, but there was no recovery of nerve function within 50 days following injection of substantially smaller doses of TPPS. Ultrastructural examination of motor nerves at various times following TPPS injection revealed the gradual development of structural abnormalities. Ultrastructural examination of the same nerves after a single dose of either ALA or HpD failed to demonstrate any abnormalities. The present observations call for precaution as to the use of TPPS as photosensitizer in human cancer treatment.

Aminolevulinic Acid↗
PubMed1978

Gradual reduction of neuroleptic drugs among chronic schizophrenics. A double-blind controlled study.

Neuroleptic drugs were gradually reduced from 25 hospitalized chronic schizophrenics while 23 such patients were maintained on matched dosages of neuroleptics. At the end of 15 weeks, 74% of the drug-reduced subjects and 80% of the drug-maintained subjects were rated to have decompensated. Drug-reduced patients decompensated while receiving a mean of 75 mg equivalent of chlorpromazine. Clinical stability was obtained at 150 mg equivalent of chlorpromazine. Twenty-six percent of the drug-reduced patients showed no signs of clinical relapse at the end of the 15-week trial and were receiving a mean of 8 mg equivalent of chlorpromazine. The results suggest that gradual and successive reductions in maintenance antipsychotic drugs can be implemented with minimal risk to the clinical status of the chronic mental patient.

Chlorpromazine↗
PubMed1978

Anterolateral rotatory instability of the knee joint. An early analysis of the Ellison procedure.

Our experience with the Ellison procedure for the control of anterior subluxation of the lateral tibial plateau includes fifty-two knees in which we used this procedure either alone or in combination with other reconstructive procedures. The results directly attributable to the Ellison procedure itself after follow-ups of six months or more could be evaluated in fifteen patients who had only the Ellison procedure for anterolateral instability and in thirteen who had both this procedure and a pes anserinus transfer for combined anterolateral and anteromedial instability. Of the twenty-eight patients so evaluated, only sixteen (57 per cent) had good or excellent results. The pivot-shift phenomenon, present in all twenty-eight knees preoperatively, had been eliminated in only four at follow-up. A positive anterior drawer sign was present in all patients both before operation and at follow-up. The subjective and functional improvement did not correlate well with the clinical and roentgenographic findings. From this study it is our impression that the results of this operation are disappointing and that it should be used only as an adjunctive procedure in lateral reconstruction in young patients.

Adolescent↗
PubMed1976

Inhibition of parental tumor colony formation by cells from a semi allogeneic mixed spleen cell reaction.

Cells capable of inhibiting colony formation by the DBA/2 fibrosarcoma SaD2-AG and mammary adenocarcinoma CaD2 are generated in vitro during semiallogeneic histoincompatibility reactions between DBA/2 and (C3H/He X DBA/2)F1 hybrid spleen cells. These colony-inhibiting cells adhere strongly to plastic, develop from nonadherent precursors, and retain colony-inhibiting ability even after receiving 5,000 rads of ionizing radiation.

Adenocarcinoma↗
PubMed1976

Metabolism of histamine in secreting and isolated canine stomach.

Total 14C activity in juice secreted by gastric pouches of six dogs and seven isolated canine stomachs was determined in response to intravenous and intra-arterial infusions of histamine and [14C]histamine. The proportions of 14C attributable to histamine, Nalpha-methylhistamine (NalphaMeH), Nalpha,Nalpha-dimethylhistamine (NalphaNalphaMe2H), N-telle-methylhistamine (NtauMeH), imidazole acetic acid (ImAA), N-methylimidazole acetic acid (NtauMeImAA), acetylhistamine (AcH), and histaminol (HOH) were defined using thin-layer chromatography. Similar estimates were made at the end of infusions on blood, gastric mucosa, and gastric muscle. Methylation was the major, or sole, route of metabolism of histamine in the gastric mucosa, and the major product was inactive NtauMeH. Small quantities of the active NalphaMe derivatives, particularly NalphaNalphaMe2H, were identified in both the juice and mucosa. Little or no ImAA, NtauMeImAA, AcH, and HOH were present in juice from isolated stomachs while they did occur in the juice from intact dogs, demonstrating they are extragastric metabolites of histamine. A major mucosal function of methylation of histamine is inactivation, although NalphaMe derivatives formed may play a role in the secretagogue action of histamine.

Acetates↗
PubMed1976

Tension studies of human knee ligaments. Yield point, ultimate failure, and disruption of the cruciate and tibial collateral ligaments.

Ultimate failure strengths of human tibial collateral and anterior and posterior cruciate ligaments were determined at two different loading rates (12.5 and fifty centimeters per minute) using an Instron Tension Analyzer. The posterior cruciate ligament was significantly stronger than the tibial collateral and anterior cruciate ligaments, which were of equal strength. At ultimate failure the ligaments were intact macroscopically but electron microscopy revealed widespread disruption of the collagen fibrils. Only after further application of stress did actual macroscopic disruption occur, suggesting that microscopic failure of the collagen fibrils in grossly intact ligaments may be a significant cause of clinical instability.

Collagen↗
PubMed1975

Potentiation by carbon tetrachloride of the immunosuppressive effects of fibrosarcoma and toxic material produced by fibrosarcoma cells.

SaD2-AG fibrosarcomas growing in DBA/2 mice caused nonspecific immunodepression. Injection of soluble material produced by cultured SaD2-AG cells into normal DBA/2 recipients caused nonspecific immunodepression and signs of systemic toxicity. These in vivo effects were enhanced by prior treatment of the recipients with carbon tetrachloride (CCl4). In contrast, material released by syngeneic fibroblasts was neither immunosuppressive nor toxic to normal mice or mice previously treated with CCl4. A soluble toxic material released by the fibrosarcoma cells may be responsible for at least some of the systemic effects of localized SaD2-AG tumors growing at a site not involving vital structures, and a protective host mechanism whose maximum capacity can be decreased by the administration of CCl4 may minimize the toxic effects of the cancer-derived material.

Animals↗