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Biomedical subjects

L Carr

Publications and source records attributed to L Carr.

66 records · Page 4Linked to original sources

Epidermoid cyst of testicle. Ultrasonographic characteristics.

Epidermoid cyst is a benign lesion of the testis which represents approximately 1 per cent of all testicular tumors. We describe a case in which preoperative ultrasound of the testis suggested a benign testicular lesion, thus permitting testis-sparing surgery. The proper management of this lesion remains a source of urologic controversy, and we review the rationales for both radical orchiectomy and simple excision.

Adult↗

Interaction between estradiol and prolactin on vasoactive intestinal peptide concentrations in the hypothalamus and in the anterior pituitary of the female rat.

To determine whether vasoactive intestinal peptide (VIP) can be regulated by modification of plasma estradiol and prolactin levels, VIP concentrations in various structures of the rat brain and in the pituitary were measured in hyperprolactinemic female rats by means of a specific radioimmunoassay for the peptide. In ovariectomized rats treated with estradiol (E2) implants alone and with both E2 and pituitary grafts to induce an experimental hyperprolactinemia, VIP levels decreased in the anterior and mediobasal hypothalamus and increased in the pituitary as compared to ovariectomized rats. No modification of hypothalamic VIP concentrations was observed in ovariectomized rats with pituitary grafts only, whereas a significant increase was found in the pituitary. These results suggest that, in the female rats, E2 exerts an effect on hypothalamic VIP levels, probably through indirect mechanisms, and that this action can be enhanced by elevated plasma prolactin levels.

Animals↗

Adenylyl cyclase responsiveness to guanyl nucleotides in the developing rat heart.

Guanyl nucleotides are effective activators of rat heart adenylyl cyclase activity from the earliest age studied, 16 fetal days, through adulthood. Both guanosine triphosphate and guanylyl-imidodiphosphate (GMP-PNP) significantly enhance epinephrine-stimulated adenylyl cyclase activity at all fetal and postnatal ages. The dose-response curves for epinephrine alone, GMP-PNP alone, or for the combination of epinephrine and GMP-PNP are similar for the newborn and adult heart preparations. Our results indicate that the epinephrine-guanyl nucleotide-adenylyl cyclase system is "mature" as a functional unit in the rat heart even prior to birth. The rat heart adenylyl cyclase system shows a dramatic increase in responsiveness to epinephrine and to guanyl nucleotides just before birth, a responsiveness which rapidly falls by 3 days of neonatal life. With increasing age, the absolute guanosine triphosphate or GMP-PNP activated rate rises in parallel with the basal rate of adenylyl cyclase activity in the rat heart. Speculation. The activation of adenylyl cyclalse systems by guanyl nucleotides may be a general feature of fetal as well as of adult tissues. This activation by guanyl nucleotides may magnify tissue hormonal responses at some stages of development.

Adenylyl Cyclases↗

Copayments for ambulatory care: penny-wise and pound-foolish.

The California "copayment experiment" imposed a charge of $1 on certain Medicaid beneficiaries for the first two visits to a doctor and 50 cents for the first two drug prescriptions each month, effective January 1, 1972. Data on utilization rates were gathered for six months before this date and for 12 months after it. While other administrative requirements, like prior authorization of certain services, doubtless also played a part, it was found that, following the start of copayment, utilization of ambulatory doctor's office visits and other services associated with them showed a decline, relative to that of the non-copayment cohort. After a brief lag, however, hospitalization rates in the copay cohort rose to levels higher than those of the non-copayment cohort-more than offsetting the savings to the state from the reduction of ambulatory service use rates. Due presumably to the neglect of early medical care because of the inhibiting effect of the copayments, these higher use rates of costly hospitalizations suggest that financial deterrents on access to ambulatory service by poor people are penny-wise and pound-foolish, not to mention their effects on health and well-being.

Aid to Families with Dependent Children↗

The last visit.

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Adult↗

Solid state chemical instability of an asparaginyl residue in a model hexapeptide.

The chemical stability of an Asn-hexapeptide (Val-Tyr-Pro-Asn-Gly-Ala) in lyophilized formulations was evaluated as a function of the pH of the bulk solution, temperature, and residual moisture content in a factorial study. Degradation pathways and product distribution in solid state were determined and characterized. It was shown in this study that the pH of the starting solution had a significant effect on the rate of deamidation and product distribution. In general, better stability for the Asn-hexapeptide was achieved at a slightly acidic pH range (3-5) in the solid state. The effects of residual moisture level and temperature on peptide stability proved to be less significant. A statistically significant two-factor interaction indicated that the pH of formulation solution determined the extent to which the peptide stability depends on moisture level and temperature. In general, the degradation of the Asn-hexapeptide in the solid state was similar to that observed in solution, except for the observation that no isoAsp-hexapeptide was detected at pH 5.0 in the solid state, whereas this was the major degradation product in solution.

Asparagine↗

Perceptions of complete dentures by prospective implant patients.

PURPOSE: The purpose of this study was to facilitate the recognition of denture patients who are unable to adapt to conventional dentures and who are likely to benefit from treatment using implant-supported prostheses. MATERIALS AND METHODS: Sixty-nine patients who where referred for postgraduate prosthetic treatment at Wits Dental School completed a self-report inventory of items related to their dentures in current use. Conventional dentures were fabricated for all subjects. Those patients who could not adapt to conventional complete denture treatment were referred for treatment with implant-supported prostheses provided that they conformed with the recommended criteria for this treatment modality. RESULTS: Analysis of the inventory of pretreatment denture complaints yielded variables that differentiated between the group who remained with conventional dentures and the group that was referred for implants. Significant variables were the period that a mandibular denture was used before new dentures were requested (P = 0.025); the period that a maxillary denture was used before further treatment was sought (P = 0.03); the discarding of a mandibular denture (P = 0.035); and pain complaints related to maxillary dentures (P = 0.045). A logistic regression model was used to compare the clinical division of the sample with that determined by the mathematic model. Sixty-six percent of the subjects who accepted conventional treatment and 69% of implant patients corresponded for both classifications. CONCLUSION: The authors conclude that pretreatment denture complaints can be used diagnostic aids for evaluating patients who are likely to benefit from implant-supported prostheses.

Chi-Square Distribution↗