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Biomedical subjects

J Oh

Publications and source records attributed to J Oh.

101 records · Page 6Linked to original sources
PubMed1991

Synthesis and biological activity of novel 3-(2-propenyl)-cephalosporins. I.

The synthesis, antibacterial activity and oral absorption of novel cephalosporins (3a-3d) having a 2-propenyl group at the C-3 position are described. Diphenylmethyl 7-amino-3-(2-propenyl)-3-cephem-4-carboxylate HCl (4) prepared from 7-aminocephalosporanic acid in 12 steps was acylated with various acid moieties to give cephems 3a-3d. The cephems 3a-3c showed similar antibacterial activities as cefixime. However, these cephems were not well absorbed orally.

Absorption↗
PubMed1990

Nucleotide sequence analyses of the genes encoding the HN, M, NP, P, and L proteins of two host range mutants of Sendai virus.

Comparative nucleotide sequence analyses of the genome of Sendai virus (strain Z) and two host range mutants, ts-f1 and F1-R, previously described revealed that the ts defect of ts-f1 can be attributed to two nucleotide exchanges in the NP gene. These exchanges lead to a single amino acid substitution. A single base pair change was found in both the P and L genes of F1-R, but not of ts-f1. Both host range mutants have the two same exchanges in the M gene. These additional mutations are discussed concerning their significance in the pantropic properties of the host range mutants.

Animals↗
PubMed1981

Vitamin A in experimental herpetic keratitis.

Systemic vitamin A palmitate at three dosage levels was evaluated for its effect on experimental herpes simplex virus (HSV) keratitis in corticosteroid-treated rabbits. High-dose vitamin A palmitate reduced the severity of herpetic keratitis, but the low or moderate doses did not, and none of the vitamin A treatments affected virus recovery. Vitamin A treatment, however, produced substantial weight loss in uninfected rabbits and in corticosteroid-treated, HSV-infected rabbits. Steroid treatment alone significantly increased the antibody response to HSV, but this effect was not enhanced by vitamin A. The slight beneficial effect on HSV keratitis could be attributed to the known effect of vitamin A on promoting epithelial healing rather than an enhancement of immunity. For this purpose, local application of vitamin A may be just as effective and much less toxic than administration for systemic effect.

Animals↗
PubMed1981

Thygeson's superficial punctate keratitis.

Thygeson's superficial keratitis is a chronic disease of the cornea characterized by focal epithelial lesions. We studied 45 cases of Thygeson's superficial punctate keratitis. Twenty-eight were male and 17 were female patients. The disease had been active in our patients from one month to 24 years. The clinical findings, course, outcome, and response to therapy were studied. Viral cultures and microscopic studies were performed on the corneal epithelial scrapings from ten cases. The average course of the disease was prolonged in patients who received topical steroid therapy. Subepithelial opacities were seen more frequently in patients who had received treatment with idoxuridine (IDU).

Adolescent↗
PubMed1976

Phytoestrogens: adverse effects on reproduction in California quail.

Phytoestrogens, largely formononetin and genistein, are produced in the leaves of stunted desert annuals in a dry year. When ingested by California quail, these compounds apparently inhibit reproduction and prevent the production of young that will not have adequate food. In a wet year, forbs grow vigorously and phytoestrogenic substances are largely absent. Quail then breed prolifically and the abundant seed crop carries the enlarged population through the winter.

Animals↗
PubMedDate not supplied

Effect of estradiol on DHEAS production in the human adrenocortical cell line, H295R.

OBJECTIVE: To determine if estradiol regulates DHEA and DHEAS production in a human adrenocortical (H295R) cell line and to determine if this effect is receptor mediated. METHODS: NCI-H295 (H295R) cells were rinsed and placed in phenol red free Dulbecco's Modified Eagle's-F12 medium supplemented with 0.1% charcoal-stripped serum. After 24 hours, cells were rinsed and treated based on experimental design. The effects of estradiol were investigated by: 1) treatment of cells with increasing concentrations of estradiol (300-3000 nmol/L) with or without forskolin (10 mumol/L), 2) treatment of cells with the nonsteroidal synthetic estrogen diethylstilbestrol (DES) (300-3000 nmol/L) with or without forskolin (10 mumol/L), and 3) treatment of cells with an estradiol antagonist (ICI 182, 780) in the presence of estradiol. RESULTS: Estradiol alone increased the basal production of DHEAS in H295R cells in a concentration-dependent manner with a maximal effect at 1000 nmol/L. Forskolin treatment increased the basal production of DHEAS ten-fold. Estradiol also increased the forskolin stimulation of DHEAS production two-fold. In contrast, DES alone or DES in addition to forskolin did not stimulate DHEAS production. Estradiol, in contrast, inhibited H295R adrenal cell production of cortisol whereas DES exhibited a similar inhibition. The estrogen receptor antagonist ICI 182,780 was unable to inhibit the stimulatory effect of estradiol. Finally, estradiol in a concentration-dependent manner suppressed 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) activity in H295R adrenal cells. CONCLUSION: These experiments support the role of estradiol in regulation DHEAS production by inhibiting 3 beta HSD activity; however, the mechanism appears to require high concentrations of estradiol and appears to be independent of the estrogen receptor.

3-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Antigen-specific humoral and cellular immune responses can be modulated in rhesus macaques through the use of IFN-gamma, IL-12, or IL-18 gene adjuvants.

DNA or nucleic acid immunization has been shown to induce both antigen-specific cellular and humoral immune responses in vivo. Moreover, immune responses induced by DNA immunization can be enhanced and modulated by the use of molecular adjuvants. To engineer the immune response in vivo towards more T-helper (Th)1-type cellular responses, we investigated the co-delivery of inteferon (IFN)-gamma, interleukin (IL)-12, and IL-18 genes along with DNA vaccine constructs. We observed that both antigen-specific humoral and cellular immune responses can be modulated through the use of cytokine adjuvants in mice. Most of this work has been performed in rodent models. There has been little confirmation of this technology in primates. We also evaluated the immunomodulatory effects of this approach in rhesus macaques, since non-human primates represent the most relevant animal models for human immunodeficiency virus (HIV) vaccine studies. As in the murine studies, we also observed that each Th1 cytokine adjuvant distinctively regulated the level of immune responses generated. Co-immunization of IFN-gamma and IL-18 in macaques enhanced the level of antigen-specific antibody responses. Similarly, co-delivery of IL-12 and IL-18 also enhanced the level of antigen-specific Th proliferative responses. These results extend this adjuvant strategy in a more relevant primate model and support the potential utility of these molecular adjuvants in DNA vaccine regimens.

AIDS Vaccines↗
PubMedDate not supplied

Concurrent use of foscarnet and ciprofloxacin may increase the propensity for seizures.

OBJECTIVE: To report a possible interaction between foscarnet and ciprofloxacin in two patients with AIDS, cytomegalovirus (CMV) retinitis, and disseminated Mycobacterium avium complex (MAC) infection and to review the available literature related to foscarnet-associated seizures. DATA SOURCE: Case report information was obtained from Medical Service Daily Rounds during the patients' hospitalization and from the patients' medical records. Computerized (MEDLINE) and manual (Index Medicus) search methods were used to obtain English-language literature published between 1980 and 1993. DATA SYNTHESIS: Foscarnet is a synthetic antiviral agent with activity against herpesviruses and HIV. The incidence of seizures with foscarnet infusion is high, ranging from 13 to 15 percent. Predisposing factors such as renal impairment, electrolyte and metabolic abnormalities, and underlying neurologic disorders have been associated with seizures during foscarnet therapy. We describe two patients with AIDS who developed generalized tonic-clonic seizures while receiving foscarnet and ciprofloxacin for the treatment of CMV retinitis and disseminated MAC infection, respectively. Neither of the patients had any of the aforementioned risk factors for foscarnet-associated seizures. CONCLUSIONS: Concurrent administration of ciprofloxacin, a known epileptogenic agent, and foscarnet may predispose patients to the development of seizures.

AIDS-Related Opportunistic Infections↗