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Biomedical subjects

C L King

Publications and source records attributed to C L King.

68 records · Page 4Linked to original sources
PubMed1989

Regulation of immunoglobulin production in hyperimmunoglobulin E recurrent-infection syndrome by interferon gamma.

The hyperimmunoglobulin E recurrent-infection (Job) syndrome (HIE) is a congenital disorder characterized by high serum IgE, chronic eczematoid dermatitis, and recurrent infections. We examined the effect of interferon gamma (IFN-gamma) on excessive IgE production in HIE patients. Spontaneous in vitro production of IgE by peripheral blood mononuclear cells from HIE patients was elevated compared to normal individuals and correlated with serum IgE. In 9 of 13 patients, IgE production by peripheral blood mononuclear cells was inhibited by 50% by IFN-gamma at 100-1000 units/ml, whereas inhibition by IFN-gamma at 10(4) units/ml ranged from 67 to 93% for these 9 patients. IFN-gamma also inhibited IgG1, IgG3, and IgG4 production by B lymphocytes without inhibiting IgG2 production. IFN-gamma was administered subcutaneously to 5 HIE patients. After 2 weeks of treatment with IFN-gamma (0.05 mg/m2) at three doses per week given on alternate days, peripheral blood mononuclear cells from all 5 HIE patients decreased spontaneous in vitro IgE production (27-62% decrease) with no change in IgG and IgM. One patient had a 58% decrease in serum IgE and another patient had a 50% decrease in serum IgE after the IFN-gamma was increased to 0.1 mg/m2 for three doses per week for a month. In both patients, serum IgE returned to pre-IFN-gamma-challenge levels 1-3 months after completion of treatment, and in vivo IFN-gamma did not affect serum IgG and IgM, although serum IgG4 decreased with changes in serum IgE. Our studies demonstrate that IFN-gamma can regulate production of IgE and some IgG subclasses in humans.

Antibody Formation↗
PubMed1989

Avoidance training using an incremental vertical jump response in rats.

A procedure is described for conditioning a vertical jump avoidance response in rats. Employing an auditory signal and gradually increasing the height of the response platform, rats showed rapid acquisition of a jump response to avoid shock. While the average maximum height of the jump response increased between original training and retraining 7 days later, retraining 40 days later resulted in stable responding that was consistent with the first retraining session.

Animals↗
PubMed1986

Mechanisms involved in the induction of malignant cell differentiation.

Cancer appears to be a disease of altered maturation, with changes in genetic expression leading to a situation in which the physiological regulation of cellular proliferation and maturation are altered. Environmental factors as well as defined chemical agents have been demonstrated to have the capacity to convert neoplastic cells to end-stage forms with a finite life span through a process characteristic of cellular maturation. The correction of genetic defects by these inducers of differentiation does not appear to be required; the critical feature is that the differentiated cells assume a state in which they no longer possess the capability for continued cellular replication. The extrapolation of these advances, accomplished in experimental systems, to clinical practice should yield significant decreases in the neoplastic cell burden without the degree of morbidity produced by aggressive therapy with cytodestructive agents, especially when employed in multidrug combinations. The ultimate introduction of differentiation as a therapeutic approach to cancer treatment if attained, however, will require a variety of principles to be established, so that optimum efficacy may be obtained from each agent, the fabrication of new agents with major changes in the ratio of the concentrations required to produce cytotoxicity relative to those necessary to initiate maturation is attained, and the elucidation of non-antagonistic combinations of differentiation inducing agents with or without cytotoxic drugs is achieved to combat the problem of tumor cell heterogeneity.

Animals↗
PubMed1984

Alkylation of DNA by the new anticancer agent 3,6-diaziridinyl-2,5-bis(carboethoxyamino)-1,4-benzoquinone (AZQ).

The bifunctional cross-linking activity of 3,6-diaziridinyl-2,5-bis(carboethoxyamino)-1,4-benzoquinone (AZQ, NSC 182986) on isolated calf thymus DNA was studied, using ethidium bromide fluorescence assay. Between 1 and 350 microM AZQ produced a dose-dependent cross-linking effect in the presence of a 10-fold excess of sodium borohydride. No cross-linking was observed in the absence of the reducing agent. AZQ can also be activated by NADH and NADPH at pH 4. The AZQ cross-linking activity exhibited a strong pH dependency, highest at acidic pH, lower at alkaline pH and not seen under neutral conditions. It was also significantly inhibited under anaerobic conditions. At pH 5 the binding ratio was 1 molecule of AZQ per 191 bases at an AZQ dose of 300 microM. Our results suggest that reduced AZQ behaved like a bifunctional alkylating agent.

Alkylation↗
PubMed1984

Induction of DNA strand breaks and cross-links by 2,5-diaziridinyl-3,6-bis(carboethoxyamino)-1,4-benzoquinone in Chinese hamster ovary cells.

The DNA-damaging effects of 2,5-diaziridinyl-3,6-bis(carboethoxyamino)-1,4-benzoquinone (AZQ) in Chinese hamster ovary cells were investigated. As determined by alkaline elution, DNA strand breaks were observed in cells treated with 50 microM AZQ for 2 hr. The single-strand break frequency was 31.3 +/- 5.3 (S.D.) rad equivalents. Strand breaks could also be detected at lower drug concentration if proteinase K treatment was included before DNA elution. In comparison, DNA cross-links were apparent in cells treated with as low as 6.25 microM AZQ. The cross-linking frequencies were 39.7, 124.3, 230.3, and 625.1 rad-equivalents for 6.25, 12.5, 25, and 50 microM AZQ, respectively. Both DNA-DNA and DNA-protein cross-links in AZQ-treated cells were revealed by the proteinase K assay. The DNA strand breaks induced by AZQ were rapidly rejoined within 1 hr after drug removal. DNA interstrand cross-links increased within the first 6 hr of postincubation and then slightly decreased by 12 hr, and most of the cross-links disappeared after cells were allowed to recover for 24 hr. DNA-protein cross-links were immediately formed during the drug treatment period and were gradually decreased after drug removal.

Animals↗
PubMed1982

Prevalence and intensity of Schistosoma haematobium infection in six villages of upper Egypt.

A cross-sectional survey for Schistosoma haematobium infection in 5,998 individuals, representing 31,803 persons in six rural villages of the Qena governorate, Upper Egypt, was completed. There were 2,223 persons (37.1%) excreting S. haematobium eggs identified by the nuclepore membrane filtration technique of a single urine specimen. Prevalence of infection ranged from 23.9% to 64.0% among the six villages. Quantitatively the overall geometric mean egg-count was 48.1 eggs/10 ml urine. A survey of proximal canals was conducted and 9 of 4,312 Bulinus snails were infected with schistosomes (0.21%). The stools of 2 of 507 adolescent males were positive for S. mansoni. No Biomphalaria snails were found. When these findings are compared to past studies, S haematobium prevalence appears to have substantially increased.

Adolescent↗
PubMed1979

Prevention of Russian influenza by amantadine.

We tested the effectiveness of amantadine hydrochloride in prevention of illness and infection caused by Russian (h1n1) influenza. The trial lasted seven weeks and was double-blind and placebo controlled. The dosage used was 200 mg daily. Efficacy in prevention of serologically confirmed clinical influenza was 70.7%. Efficacy in prevention of infection, symptomatic or asymptomatic, was 39.4%. Side effects seen were all mild, began within two days of the start of the trial, and terminated rapidly on cessation of prophylaxis. The withdrawal rate attributable to use of amantadine was 6.2%. Those who continued to receive prophylaxis for the remainder of the trial did not exhibit excess side effects. It is concluded that amantadine is safe and effective in prophylaxis of H1N1 strains, as has been shown previously for other subtypes of A influenza.

Adolescent↗
PubMedDate not supplied

Cloning, sequencing, and homology analysis of nonhuman primate Fas/Fas-ligand and co-stimulatory molecules.

The finding that a single administration of select recombinant human cytokines to nonhuman primates leads to potent cytokine-neutralizing antibody responses in the heterologous host despite >95% homology at the nucleotide and protein level prompted our laboratory to clone, sequence, and prepare recombinant nonhuman primate cytokines, chemokines, growth factors, and other immunoregulatory molecules. In the present report, we present findings on the gene sequences encoding the nonhuman primate homologues of human CD80, CD86, their ligands CD28 and CD152, CD154, CD95, and CD95-L from rhesus macaques and for phylogenetic analysis from pig-tailed macaques, African sooty mangabey monkeys, baboons, and vervets as well as select molecules from the New World aotus and marmoset monkeys. With the exception of CD95, the homology between nonhuman primate and human co-stimulatory molecules was above 95%. In contrast, CD95 was only 89.2% homologous to human CD95, but the differences were essentially found in the transmembrane and intracellular (death) domains. The extracellular portion of CD95 was more homologous which was in accordance with approximately 98% homology between Old World monkey and human CD95-L. In general, sequences from the New World monkey species appeared equidistant to sequences from Old World species and humans in terms of homology suggesting distinct evolutionary patterns. Of interest was the isolation of various splice variants of monkey CD86, CD152 (CTLA-4), CD154, and CD95 transcripts. This is also the first report documenting the occurrence of natural CD86 variants with deleted transmembrane domains, found both in sooty mangabeys and baboon RNA samples. Monkey CD95 showed various deletions and addition of residues in the transmembrane and intracytoplasmic domains compared with human CD95 and between Old and New World species. Subcloning of rhesus CD154 into an expression vector demonstrated expression of a functional protein in cell culture. The other genes are being cloned into expression vectors for the preparation and biological characterization of the nonhuman primate molecules. These investigations will provide novel reagents for in vivo use as immunomodulatory reagents in nonhuman primates in studies which may provide a rationale for their use in humans.

Abatacept↗
PubMedDate not supplied

Uterotonic effect of Evodia rutaecarpa alkaloids.

Rutaecarpine (1) and dehydroevodiamine (2) were isolated from the unripe fruit of Evodia rutaecarpa. In vitro uterotonic assay on rat uterus showed both alkaloids to be active. Dehydroevodiamine was further shown to be active in the in vivo uterotonic assay using rats as the animal model. Reference evodiamine hydrochloride (3) was also evaluated and found to be devoid of uterontonic activity at the doses administered.

Alkaloids↗
PubMedDate not supplied

Human immune responses to lymphatic filariasis in Papua New Guinea.

The following review highlights our current knowledge about the host immune response to lymphatic filariasis. Our understanding of how the host immune response influences the risk of developing disease has changed dramatically over the past decade. Previously the spectrum of disease associated with lymphatic filariasis was largely attributed to the nature of the host immune response. Now we appreciate that the duration and intensity of infection and possibly the direct influence of parasite-derived molecules also determine the risk of disease. The review highlights recent studies examining the influence of transmission intensity on the host immune response, and how this might be mediated by defects in antigen-presenting cell function, and also the role of basophils and mast cells.

Animals↗