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Biomedical subjects

J Christopher

Publications and source records attributed to J Christopher.

At least 19 recordsLinked to original sources
PubMed1995

Hepatitis C-related chronic liver disease among asymptomatic blood donors in the north west of England.

In the first 19 months of screening, the North Western Regional Transfusion Centre (RTC) tested 224,000 consecutive blood donors for antibody to hepatitis C virus (anti-HCV) by second generation enzyme immunoassay (EIA). Of these, 366 repeatedly reactive samples were referred for confirmatory testing at Manchester Public Health Laboratory (PHL). There, the initial EIA was repeated, together with two further EIAs. All the referred samples were subjected to a confirmatory line immunoblot (RIBA-II). Reverse transcription followed by the polymerase chain reaction (RT-PCR), in order to detect viral RNA, was performed on selected samples. Among the donors, 61 accepted offers for medical review and were assessed for risk factors, clinical findings and results of standard liver function tests. Of these donors, 53 proceeded to liver biopsy. The overall prevalence of confirmed positive donors was 0.04%. Main risk factors identified included intravenous drug abuse in 31 (51%) donors and prior blood transfusion in 12 (20%) but a risk factor was not apparent in 11 (18%). Viraemia, detected by RT-PCR, could be predicted with a high degree of accuracy by means of the readily available and simpler screening and confirmatory tests (EIA and RIBA-II). Established chronic hepatitis was demonstrated in 90% of the liver biopsies. A trend towards worsening histological findings accompanied increasing concentrations of serum transaminase. Even so, many donors with normal transaminase values had abnormal biopsies including those showing chronic active hepatitis (CAH). These findings indicate that a substantial proportion of previously unrecognised asymptomatic persons with established chronic liver disease exists among North Western blood donors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Self-reported anger in black high school adolescents.

The purpose of this study was to explore the recognition and expression of anger in black high school adolescents. A total of 56 teens, aged 14-19 years, responded to questions about their recognition of anger, how and to whom they express anger, and to whom they refrain from expressing anger. They also stated their opinions about acceptable and unacceptable expressions of anger and its relationship to depression or suicide. Data were analyzed using frequency tabulations for all questions on the survey instrument. Specific variables of age, grade in school, gender, and family composition were analyzed by one-sample chi 2 tests (alpha set at 0.05). The study demonstrated 1) all the teens surveyed could recognize when they were angry; 2) most teens expressed anger to their friends, to their siblings, and to their mothers; 3) younger teens (ages 14-15 years) when compared to older teens (ages 18-19 years), identified mother as the one who made them angry; 4) females were more likely to feel like crying when angry; 5) females were more likely to feel like being silent when angry; 6) students from one- and two-parent homes did not differ in their expression of anger. Implications of this study include the recognition that anger is a natural, human emotion. Adolescents need to observe adults who can effectively manage behavior associated with anger. Problem solving skills, stress management techniques, and role play situations can be utilized as effective tools in the recognition and expression of anger in acceptable ways and in attempts at the prevention of dysfunctional anger.

Adolescent↗
PubMed1979

Acridine araphanes: a new class of probe molecules for biological systems.

The bis-acridine ring system forms the basis for new biophysical probes of novel stereochemistry. Spectral data indicate that certain alkylene bridged bis-9-aminoacridines have a parallel plane conformation of predictable interplane distance. The parallel plane conformation is independent of solvent and thus is different from nucleic acid systems. This stable conformation allows these compounds to be used as sensitive "rulers" for describing binding site geometry in cholinergic enzymes and in the delineation of the mechanism of allosteric control in acetylcholinesterase.

Acetylcholinesterase↗
PubMed1978

Megavitamins for minimal brain dysfunction. A placebo-controlled study.

Preliminary to a stimulant comparison study, 31 children with minimal brain dysfunction randomly received either placebo or a megavitamin combination. During a two-week trial, only two children responded so well that stiumlants were not considered necessary; both were in the placebo group. Change scores from pretest to posttest on four blind ratings by teachers and parents did not show a significant difference between the placebo and vitamin groups.

Ascorbic Acid↗
PubMed1978

Methylphenidate vs dextroamphetamine vs caffeine in minimal brain dysfunction: controlled comparison by placebo washout design with Bayes' analysis.

Double-blind crossover comparison of methylphenidate hydrochloride, dextroamphetamine sulfate, and caffeine after placebo washout in 29 children with minimal brain dysfunction (MBD) showed on six ratings that methylphenidate and dextroamphetamine were significantly (P less than .05 to P less than .001) better than placebo and caffeine, but not significantly (P less than .05) different from each other. Placebo, caffeine, and ratings before drug did not differ significantly. Of 26 drug responders, 12 responded best to dextroamphetamine, ten to methylphenidate, and one to caffeine. The latter child showed no improvement at all with either prescription stimulant. Methylphenidate and dextroamphetamine were each efficacious for six children who did not respond to the other stimulant. All three drugs showed significant (P less than .05) weight loss and cardiovascular side effects, the latter possibly spurious. Dextroamphetamine showed a significant (P less than .05) decrease from placebo in "tummyaches."

Attention Deficit Disorder with Hyperactivity↗
PubMed1975

Effect of milk and casein on the absorption of supplemental iron in the mouse and chick.

Milk is an attractive vehicle for introducing iron supplements into iron-deficient infants and children. This study compares the effects of milk and caseins on the whole-body absorption of radioactive iron complexes in an attempt to resolve the controversy over whether milk and its constituent phosphoproteins seriously impair iron absorption. Evidence is presented to clarify the role of the calcium-casein micelles of cow's milk in binding iron donated by the ferric-nitrilotriacetate (NTA) complex. The absorption of iron from isolated Fe(III)-casein complexes was studied in mice as a function of the casein--to--Fe ratio and was compared with the absorption of Fe(III)-NTA at equivalent levels. Even at casein--to--Fe ratios higher than those found in conventional iron-supplemented cow's milk (10-15 mg Fe/qt; casein P:Fe congruent to 34), absorption of iron(III) from the casein or NTA complex was not significantly different. There was no significant difference in the absorption of iron administered to mice and chicks as ferrous ion, ferric-NTA, or ferric fructose; nonfat cow's milk did not inhibit the absorption of these iron compounds. For the chick, in fact, milk significantly enhanced the absorption of iron from the ferric-NTA chelate. In order to affect iron absorption significantly casein would have to be present considerably in excess of that found in conventionally supplemented cow's milk.

Absorption↗