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Biomedical subjects

R S Chang

Publications and source records attributed to R S Chang.

At least 109 records · Page 6Linked to original sources
PubMed1985

Neuropeptide Y (NPY) binding sites in rat brain labeled with 125I-Bolton-Hunter NPY: comparative potencies of various polypeptides on brain NPY binding and biological responses in the rat vas deferens.

The binding of biologically active 125I-Bolton-Hunter (BH)-NPY to rat brain membranes was saturable and reversible and regulated by inorganic cations and guanyl nucleotides consistent with other neurotransmitter receptor systems. The concentration of specific 125I-NPY binding differed in various brain regions, being highest in the hippocampus and lowest in the cerebellum. Scatchard analysis of 125I-NPY binding showed a single class of receptor sites with a Kd = 0.1 nM and Bmax of 3 pmole/g tissue in hippocampus. Peptide YY, porcine and human NPY inhibited the specific 125I-BH-NPY binding with IC50 values of 50-120 pM. In contrast, human NPY free acid and pancreatic polypeptides from human (HPP), rat (RPP) and avian (APP) sources were much weaker (IC50 greater than or equal to 300 nM). The rank order of potencies for NPY analogs and the inactivity of APP and HPP fragment (31-36) on brain binding appeared to correlate with their relative activities in inhibiting contractions of the field-stimulated rat vas deferens. However, PYY, HPP and RPP exhibited activity in the field-stimulated rat vas deferens indicative of a possible action upon sites distinct from the brain NPY binding site.

Animals↗
PubMed1985

A potent nonpeptide cholecystokinin antagonist selective for peripheral tissues isolated from Aspergillus alliaceus.

A new, competitive, nonpeptide cholecystokinin (CCK) antagonist, asperlicin, was isolated from the fungus Aspergillus alliaceus. The compound has 300 to 400 times the affinity for pancreatic, ileal, and gallbladder CCK receptors than proglumide, a standard agent of this class. Moreover, asperlicin is highly selective for peripheral CCK receptors relative to brain CCK and gastrin receptors. Since asperlicin also exhibits long-lasting CCK antagonist activity in vivo, it should provide a valuable tool for investigating the physiological and pharmacological actions of CCK.

Animals↗
PubMed1985

Cholecystokinin receptor mediated hydrolysis of inositol phospholipids in guinea pig gastric glands.

CCK-octapeptide (CCK-8) (EC50 = 0.5 nM), in the presence of Li+, increased 3H-inositol phosphate (IP) accumulation in guinea pig gastric glands prelabeled with 3H-inositol. CCK-8 desulfate, human gastrin I and pentagastrin were much less potent than CCK-8. Antagonists of CCK receptors such as proglumide, dibutyryl-c-GMP and CBZ-Tyr (SO3H)-Met-Gly-Trp-Met-AspNH2 shifted the CCK dose response curve to the right. However, histamine (H1 and H2), cholinergic, substance P and alpha- and beta-adrenergic receptor antagonists had no effect on 3H-IP accumulation induced by CCK. The results suggest that CCK receptor activation in gastric glands leads to an enhanced breakdown of inositol phospholipids which may relate to calcium mobilization and pepsinogen secretion.

Animals↗
PubMed1985

Epstein-Barr virus infections in homosexual men with chronic, persistent generalized lymphadenopathy.

The status of infection by the Epstein-Barr virus (EBV) in 20 patients with chronic, persistent generalized lymphadenopathy was evaluated with use of three parameters: antibodies to EBV, EBV excretion, and EB virocytemia. Results were compared with those obtained from two groups of control subjects: patients with infectious mononucleosis and healthy EBV-seropositive adults. Profiles of antibody to EBV and the prevalence of EBV excretion were essentially similar for study subjects and healthy control subjects, but the level of EB virocytemia was significantly higher in study subjects than in healthy control subjects.

Adult↗
PubMed1985

Work sampling. Analyzing nursing staff productivity.

Most managers have only a vague idea of how their employees spend their time. Work sampling is a technique that can identify the types of activities that staff perform and the amount of time that they spend on each activity. With this information, managers can make decisions regarding allocation of staff and activities, thereby increasing efficiency and effectiveness of personnel. This paper describes the use of work sampling as a technique to study employee time allocation and productivity. It offers suggestions for planning, implementation, and utilization of the results of a work sampling study. A work sampling study conducted at the University of Michigan Medical Center's Psychiatric Nursing Department is used as an example.

Data Collection↗
PubMed1984

Further evidence that substance P partly mediates the action of cholecystokinin octapeptide (CCK-8) on the guinea pig ileum but not gall bladder: studies with a substance P antagonist.

The substance P antagonist, [D-Pro4-D- Trp7 ,9,10]substance P4-11, caused a pig parallel shift to the right of the cholecystokinin (CCK-8) dose-response curve in guinea pig ileum longitudinal muscle without changing the maximal contraction. The shift of the CCK-8 dose response was markedly reduced after desensitization of the tissues to substance P (SP). The SP antagonist had no effect upon CCK-8 responses of the guinea pig gall bladder, [125I]CCK pancreatic binding or contractions of the guinea pig ileum produced by acetylcholine or electrical stimulation. The data provide additional evidence for the involvement of SP in the action of CCK-8 on the guinea pig ileum but not the gall bladder.

Animals↗
PubMed1984

Interferons on the transformation of non-T blood mononuclear leukocytes by Epstein--Barr virus.

The effect of partially purified leukocyte (alpha) and fibroblast (beta)-derived interferons (IFNs) and crude immune (gamma) IFN on the transformation of non-T mononuclear leukocytes by the Epstein--Barr (EBV) virus was studied. The IFN preparations reduced the frequency of cells positive for EBV-specific nuclear antigen but did not significantly prolong the EBV-transformation interval.

Cell Transformation, Viral↗
PubMed1984

Failure to acquire Epstein-Barr virus infection after intimate exposure to the virus.

In 1981, 54 Epstein-Barr virus-seronegative pregnant women in the Sacramento-Davis area of California were observed prospectively for an average duration of 12.1 months for Epstein-Barr virus-seroconversion. Only one seroconverted. Two of the 54 women remained negative for Epstein-Barr virus antibody 4.5-5.0 months after their husbands were proved to be Epstein-Barr virus excreters. Short of experimental pharyngeal introduction of the virus into human volunteers, these data provide the most direct evidence possible that the intimate exposure of Epstein-Barr virus-seronegative adults to the virus does not necessarily result in infection.

Adolescent↗
PubMed1984

Maternal transmission of acquired immune deficiency syndrome.

Acquired immune deficiency syndrome (AIDS) has been reported in previously healthy homosexual or bisexual males, intravenous drug users, heterosexual men with hemophilia, and Haitians. The finding of heterosexual hemophiliacs with AIDS has raised the possibility of a transmittable blood-borne agent as a cause of this disease. We have found three female half-siblings who had clinical and laboratory evidence for AIDS. All three had evidence of abnormal in vitro cellular immunity; two had chronic active Epstein-Barr virus infection and lymphadenopathy; all three had chronic cutaneous Candida sp infection; and two had Pneumocystis carinii pneumonia. Their mother is a prostitute/drug addict with abnormal T-cell immunity including clinical and laboratory findings of mucocutaneous candidiasis. Histocompatibility typing is consistent with the history of different fathers for each child. Immunologic studies in one child evaluated prospectively from birth were abnormal by 2 months of age. These findings and the clinical histories indicate AIDS and strongly suggest vertical transmission of an agent(s) during the perinatal period.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Characterization of beta-adrenergic receptors in the rat vas deferens using [3H]-dihydroalprenolol binding.

The beta-adrenergic antagonist, [3H]-dihydroalprenolol ([3H] DHA), binds to membranes prepared from the rat vas deferens in a specific and saturable manner. Scatchard and Hill plot analysis indicates a single class of binding sites with no evidence of cooperative interactions. The specific binding sites have a high affinity (Kd = 0.3 nM) and a maximal occupancy estimated to be 460 fmoles [3H]-DHA bound/g wet tissue weight. Beta-adrenergic agonists and/or antagonists inhibit [3H]-DHA binding to rat vas deferens membranes in a stereospecific manner and with a relative order of potency expected for beta-adrenergic receptors of the beta2 subtype. The receptor affinities of various beta-adrenergic antagonists in the rat vas deferens determined using inhibition of [3H]-DHA binding correlated with their receptor affinities determined physiologically using antagonism of isoproterenol-induced inhibition of neurogenic contractions in-vitro.

Adrenergic beta-Agonists↗
PubMed1983

Increase in brain 125I-cholecystokinin (CCK) receptor binding following chronic haloperidol treatment, intracisternal 6-hydroxydopamine or ventral tegmental lesions.

Specific 125I-CCK receptor binding was significantly increased in brain tissue taken from guinea pig or mouse following chronic (2-3 week) daily administration of haloperidol (2-3 mg/kg/day). Scatchard analysis indicated the increase in CCK binding was due to an increased receptor number (B max) with no change in affinity (Kd). In guinea pigs, the increased CCK binding was observed in the mesolimbic regions and frontal cortex, but not in striatum, hippocampus nor posterior cortex. In mice, however, the increases occurred in both pooled cerebral cortical-hippocampal tissue, and in the remainder of the brain. Enhanced CCK receptor binding was also observed in membranes prepared from whole brain of mice one month following intracisternal injection of 6-hydroxydopamine. Additionally, an increase in CCK binding was observed in mesolimbic regions and frontal cortex, but not striatum or hippocampus, of guinea pigs 3 weeks after an unilateral radiofrequency lesions of the ipsilateral ventral tegmentum. The present studies demonstrate that three different procedures which reduce dopaminergic function in the brain enhance CCK receptor binding. The data provide further support for a functional interrelationship between dopaminergic systems and CCK in some brain regions and raise the possibility that CCK may play a role in the antipsychotic action of neuroleptics.

Animals↗
PubMed1983

Photoreceptor degeneration. Possible autoimmune disorder.

A 61-year-old woman with progressive blindness, initially responsive to steroid therapy, was found to have an undifferentiated neoplasm in the cervix uteri. Visual fields demonstrated ring scotomas and the electroretinographic pattern eventually became flat. The interval from onset of visual symptoms to blindness was 19 months. Eye pathologic findings included loss of retinal photoreceptors, a macular hole, and normal optic nerves. Antibodies were demonstrated in the patient's serum to normal fresh human retinal photoreceptors. An autoimmune mechanism may have been responsible for the retinal degeneration in this patient, and such a hypothesis raises questions about (1) autoimmune mechanisms in patients with retinitis pigmentosa and other retinal degenerative diseases and (2) autoimmune mechanisms in other cases of remote effects of carcinoma.

Autoantibodies↗
PubMed1983

Epstein-Barr virus infections during pregnancy. A prospective study and review of the literature.

Susceptibility to Epstein-Barr virus (EBV) infection in 1,729 pregnant women was evaluated by screening for EBV antibodies. Fifty-eight subjects (3.4%) had no detectable EBV antibody and were presumably susceptible. Of the 54 women who agreed to participate in this study, none acquired EBV antibody during pregnancy. Our results are in general agreement with some published reports that primary EBV infection during pregnancy is rare. The role of EBV in congenital infections and perinatal morbidity remains to be defined.

Adolescent↗