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Biomedical subjects

C Smith

Publications and source records attributed to C Smith.

At least 901 records · Page 50Linked to original sources
PubMed1985

Detection of immunologically cross-reacting capsid protein of alphaviruses on the surfaces of infected L929 cells.

Hyperimmune, but not normal immune, monospecific antiserum made to capsid protein of Sindbis virus (SIN) was found to cause cytolysis equally well of both SIN- and Semliki Forest virus-infected L929 cells in antibody-dependent, complement-mediated cytotoxicity assays. The cell surface reactivity of the hyperimmune antiserum was also demonstrated by solid-phase radioimmune assays with unfixed infected cells or infected cells fixed with low concentrations of glutaraldehyde (0.025%) before reactivity with antisera. Higher concentrations of glutaraldehyde lowered the sensitivity of detection. Purified SIN capsid protein specifically inhibited antibody-dependent, complement-mediated cytotoxicity by the monospecific anti-capsid protein serum on SIN- and Semliki Forest virus-infected target cells. That hyperimmune anti-SIN serum also cross-reacts with capsid protein on the surface of Semliki Forest virus-infected cells was suggested by the fact that capsid protein inhibited cross-cytolysis in the antibody-dependent, complement-mediated cytotoxicity assay. The latter antiserum was collected after repeated injections of purified virions over a 9-month period. The results suggest that hyperimmune monospecific antisera made to SIN capsid protein or hyperimmune antisera to SIN or Semliki Forest virions detect homologous and cross-reacting capsid protein determinants on the surface of infected cells.

Animals↗
PubMed1985

Multivariate analysis of glycosylated haemoglobin in insulin-treated diabetics.

Glycosylated haemoglobin (HbA1), as an assessment of overall control, was estimated in 858 insulin-treated diabetics attending for changeover to U100 insulin in North East Wales. Details of age, sex, duration of diabetes, insulin regimen and monitoring method were recorded. Multivariate analysis revealed lower HbA1 in patients receiving twice-daily (mean 11.01) as compared with once-daily insulin (11.42, P = 0.011), but no difference was found between urine and blood glucose testers when other variables were taken into consideration. HbA1 was lower in men (mean 10.94) compared with women (mean 11.39, P = 0.004) and there was a positive correlation of HbA1 in men with age (P = 0.046) and in women with duration of disease (P = 0.005).

Age Factors↗
PubMed1985

A double blind placebo controlled trial of ascorbic acid in obesity.

A double blind placebo controlled trial of ascorbic acid was carried out in 41 severely obese subjects. 38 patients completed the 6 week trial. 19 received 3g of ascorbic acid per day, 19 received placebo. The weight loss during the trial was small in both groups but was significantly greater in the ascorbic acid treated group.

Ascorbic Acid↗
PubMed1985

Hypothalamic dysfunction in overtrained athletes.

Some athletes who undertake strenuous training programs for a prolonged period of time develop the overtraining syndrome. The pathophysiology of the condition is unknown. Hypothalamic-pituitary function was studied by determining the hormonal responses to insulin-induced hypoglycemia in five asymptomatic male marathon runners during a 4-month period in which they ran 42-, 56-, and 92-km races and in four overtrained male athletes. The response of the asymptomatic runners was not different when tested 1 month before and within 48 h after the 42- and 92-km races. All four overtrained athletes presented with impaired training and racing times, apathy, and a heavy-legged feeling and were tested when overtrained and again after 4 weeks of rest. The plasma cortisol, ACTH, GH, and PRL responses to insulin-induced hypoglycemia in the four overtrained athletes were lower than their responses after the rest and lower than the responses of the asymptomatic runners. In both groups, the LH, TSH, and PRL responses to LHRH and TRH were normal. The impaired hormonal responses to insulin-induced hypoglycemia, with recovery after 4 weeks of rest, indicate hypothalamic dysfunction and may be a diagnostic marker of the overtraining syndrome.

Adrenocorticotropic Hormone↗
PubMed1985

1 alpha-Hydroxyvitamin D2 is less toxic than 1 alpha-hydroxyvitamin D3 in the rat.

An LD50 of 0.2 mg/kg body wt has been determined for 1 alpha-hydroxyvitamin D3 in the rat. In comparison, the LD50 for 1 alpha-hydroxyvitamin D2 is between 3.5 and 6.5 mg/kg. In terms of chronic toxicity, 1 alpha-hydroxyvitamin D3 at a dose of 5 micrograms/kg/day causes death of one-half the animals in a 4-week period. On the other hand, 20 micrograms/kg/day of 1 alpha-hydroxyvitamin D2 is required to induce similar toxicity. The body weight record and renal calcium accumulation during chronic treatment support the above conclusion. It therefore appears that 1 alpha-hydroxyvitamin D2 is between 5 and 15 times less toxic than 1 alpha-hydroxyvitamin D3. This surprising result prompted a reexamination of the relative biological activity of 1 alpha-hydroxyvitamin D2 and 1 alpha-hydroxyvitamin D3. Both compounds are equally potent in the stimulation of intestinal calcium transport, bone calcium mobilization, in the elevation of serum phosphorus, and in the healing of rickets in the rat. The reason for lower toxicity of 1 alpha-hydroxyvitamin D2 is unknown. The results suggest that 1 alpha-hydroxyvitamin D2 might represent a therapeutically superior compound.

Animals↗
PubMed1985

The effect of colonizing mice with laboratory and wild type strains of E. coli containing tumor virus genomes.

Conventional, antibiotic-compromised, and germ-free mice were either fed or subcutaneously inoculated with laboratory or wild type strains of E. coli containing monomeric or dimeric forms of polyoma (PY) virus DNA. Mice were bled at 3 and 6 weeks following administration of E. coli and their sera examined for the presence of PY hemagglutination inhibiting antibodies. None of the mice developed PY infection; despite colonization of the intestinal tract accompanied by prolonged excretion of high titers (10(9) colony-forming units/gram feces) of E. coli harboring potentially infectious PY virus DNA, no evidence of infection could be demonstrated.

Animals↗
PubMed1985

The cervical tumor-associated antigen (ICP-10/AG-4) is encoded by the transforming region of the genome of herpes simplex virus type 2.

BglII fragment C mapping between 0.416 and 0.580 map units (mu) on the herpes simplex virus type 2 (HSV-2) genome was used for in vitro translation to identify proteins encoded on this fragment. RNA homologous to the BglII C fragment directs the synthesis of three proteins with approximate molecular weights of 144,000, 52,000 and 27,000. The 27,000 dalton protein is encoded by sequences within the EcoRI/HindIII AE fragment (0.419-0.525 mu) that overlap the immortalizing sequences within BglII C. The 144,000 (144K) and 52,000 dalton proteins are encoded by sequences within the BamHI "e" fragment of HSV-2 DNA (0.535-0.585 mu). The 144K protein is the only species translated in vitro from mRNA hybrid-selected from cells arrested in the "early" (beta) phase of viral protein synthesis. It is precipitated by anti-ICP-10 serum and by monoclonal antibody 48S (previously shown to precipitate the HSV-induced ribonucleotide reductase). The 48S antibody competes with the anti-ICP-10 serum for the 144K protein. Furthermore the in vitro translated 144K protein is structurally similar to ICP-10, an HSV-2-infected cell protein that is antigenically identical to AG-4, the cervical tumor-associated antigen.

Antigens, Neoplasm↗
PubMed1985

Resection of heterotopic ossification in the adult with head trauma.

Lesions of heterotopic ossification were excised from thirty-seven joints in twenty-three adults who had had injuries to the brain. The lesions were excised from twenty-three elbows, twelve hips, and two shoulders. Patients were retrospectively divided into five categories according to the neural residua (cognitive and physical deficits). The patients in Class I (minimum cognitive and physical disability) and patients in Class II (minimum cognitive disability and moderate physical disability) who had fair or good selective control of the affected extremity had the best prognosis for maintaining the range of motion resulting from resecting the lesion and improving function postoperatively. They also had a low incidence of recurrence of the lesion. Seven of the nine elbows and eight of the eight hips in patients in these classes had successful results. All three of the patients in Class V (severe cognitive and physical deficits) who had a lesion of the hip and all eight of the patients in Class V with poor selective control had a poor result. In the twenty-five joints for which adequate follow-up radiographs were available to determine if the lesion recurred, fourteen recurrences were identified (56 per cent). Eleven of these patients were considered to have a poor result. Nine of the fourteen recurrences occurred in patients in Class V. Radiographic evidence of the maturity of the lesion and a normal level of alkaline phosphatase were of limited importance in predicting a low rate of recurrence. The over-all complications included four superficial infections and no instances of osteomyelitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Problems of inner city general practice in north-east London.

This paper looks at differences in primary health care between the inner city and suburban areas of the North-East London Faculty of the Royal College of General Practitioners. Most of the differences observed were in the expected direction. However, the inner city area did not appear worse off in terms of the proportion of doctors specifically trained for general practice, the availability of doctors outside normal surgery hours, the links between general practitioners and hospitals and the attitudes of doctors to change. The data were derived from a postal survey of general practitioner principals whose main surgery was in the faculty area.

Family Practice↗
PubMed1985

"Carryback": effect of viscous liquid controls on the preceding sample analyzed with the SMA II continuous-flow analyzer.

We systematically studied the "carryback" effect of ethylene glycol-based controls on the preceding sample on an SMA II continuous-flow analyzer. Including Beckman Level 1 unassayed liquid control material as a sample lowered the 12 analyte values of the preceding sample by an average of 2.7%, Level 2 (the most viscous) by an average of 4.4%, and Level 3 by 3.2%. Water-reconstituted lyophilized control material caused no carryback effect, but lyophilized control reconstituted with 330 mL/L ethylene glycol decreased the preceding sample's results by 4.1% (average carryback). We believe that carryback is caused by the drag placed on the sample line by a viscous sample, which decreases the volume of the preceding sample that is delivered to the reagent or pre-dilution mixing coils. Our findings were confirmed on another SMA II. Limited study of a SMAC analyzer gave inconclusive results, but further evaluation of continuous-flow systems for carryback is warranted. Carryback substantially increases total analytical variability.

Autoanalysis↗
PubMed1984

The effects of a series of capsaicin analogues on nociception and body temperature in the rat.

A series of capsaicin analogues have been synthesized in an attempt to try to separate the antinociceptive properties of capsaicin from its hypothermic effects. In capsaicin analogues with an unbranched alkyl side-chain of varying length, maximum antinociceptive and hypothermic activity was achieved with a chain length of 8-9 C atoms. Decreasing the chain length decreased both parameters equally. Substitution in the aromatic ring abolished activity. Several compounds related to homovanilloyl dodecylamide, an analogue of capsaicin in which the acylamide linkage is reversed, produced some antinociceptive activity without concomitant hypothermia, but the maximum antinociceptive effect achieved was very small. In the present series of capsaicin analogues good antinociception without hypothermia was not found.

Animals↗
PubMed1984

Action of prolactin in regressing prostate: independent of action mediated by androgen receptors.

Hyperprolactinemia, achieved by grafting pituitaries under the renal capsule, has been shown to cause a delay in the rate of castration-induced prostatic regression in rats. The mechanism of this prolactin action is not established, although it has been suggested that the action of prolactin in the rat prostate is mediated through the action of androgen. To explore the possibility that a small amount of residual endogenous androgen present in the prostate at the time of castration acts synergistically with prolactin to cause this delay in prostatic regression, Flutamide has been used in the present study in an attempt to inhibit this residual androgen effect by blocking its interaction with androgen receptors. Two experiments were conducted. In experiment 1, daily sc injections of Flutamide (25 mg/kg) for 7 days to castrated rats supplemented with dihydrotestosterone-filled silastic tubing either 1 or 4 cm long completely suppressed both prostatic weight and protein content to the level that was normally observed in castrated rats receiving empty tubings. Furthermore, treatment of Flutamide to castrated rats did not cause an increase in prostatic weight and protein content over those of castrated rats treated with the vehicle only. These results indicate that Flutamide, at this dosage, is a potent antiandrogen and that the compound itself does not have any androgenic activity in the rat prostate. In experiment 2, adult male rats were castrated and received two female pituitaries grafted under the renal capsule. One week later, their serum prolactin levels increased from 20 +/- 3 ng/ml to 102 +/- 8 ng ml. This elevated level of serum prolactin was associated with a delay in the rate of prostatic regression. Administration of Flutamide, at a dose (25 mg/kg) which completely suppressed prostatic growth, failed to inhibit the delay in prostatic regression in castrated rats bearing the pituitary grafts. Since Flutamide inhibits the androgen action in the prostate by blocking the binding of intracellular dihydrotestosterone to androgen receptors, the failure of Flutamide to block the effect of prolactin suggests that the prolactin action in regressing prostates is not mediated by androgen receptors.

Animals↗