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Biomedical subjects

C Atkins

Publications and source records attributed to C Atkins.

At least 37 records · Page 2Linked to original sources

Structure-activity profile of a series of novel triazoloquinazoline adenosine antagonists.

During a search for benzodiazepine receptor modulators, a highly potent adenosine antagonist (CGS 15943) was discovered. The compound was defined as a resonance-stabilized hybrid of the canonical structures 9-chloro-2-(2-furyl)[1,2,4]triazolo[1,5-c]quinazolin-5-amine (2a) and 9-chloro-2-(2-furyl)-5,6-dihydro[1,2,4]triazolo[1,5-c]-quinazolin- 5-imine (2b). Spectroscopic evidence and chemical reactivity in polar media favor the amine form 2a as the major contributor of the two canonical structures. The synthesis of 2 and some of its analogues and the structure-activity relationships in four biological test systems are described. Replacement of the 9-chloro group by hydrogen, hydroxyl, or methoxyl gave compounds with comparable binding potency at the A1 and A2 receptors but much less activity as antagonists of 2-chloroadenosine in guinea pig tracheal strips. Alkylation of the 5-amino group caused, in general, a loss of binding activity, particularly at the A2 receptor, as well as complete loss of activity in the tracheal model. Modification of the 2-furyl group caused a pronounced loss of activity in all of the test systems.

Adenosine↗

Rheumatic disease in the Nuu-Chah-Nulth native Indians of the Pacific Northwest.

The Nuu-Chah-Nulth are a tribe of 2,300 Pacific Northwest native Indians. A retrospective study has identified 157 requiring referral to rheumatologists over 15 years. Rheumatoid arthritis (RA) was found in 23, systemic lupus erythematosus (SLE) in 8, sacroiliitis 5, and Reiter's syndrome 1. Overlap syndromes with combinations of RA, SLE, scleroderma and polymyositis were seen in 9. Other rheumatic disorders included osteoarthritis 10, soft tissue rheumatism 14, and musculoskeletal complaints of known etiology (trauma, infection, neoplasm) 12. The remaining 75 patients suffered from periodic weather dependent joint swelling (52) or polyarthralgia (23) which were sometimes accompanied by features of systemic connective tissue disease. These findings are compared with rheumatic disease in other North American Indians.

Antibodies, Antinuclear↗

Best of both worlds.

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Appointments and Schedules↗

Assessing knowledge of cardiovascular health-related diet and exercise behaviors in Anglo- and Mexican-Americans.

This article describes the Adult and Child Behavior Knowledge Scales that were used as part of the San Diego Family Health Project to measure knowledge of health behaviors related to cardiovascular diseases in two ethnic groups: Anglo- and Mexican-Americans. The psychometric characteristics of these scales indicate acceptable reliabilities for assessing knowledge of dietary sodium, dietary fat, and exercise among both adults and children and differ from other health knowledge scales in that they focus on "behavioral capability" rather than on the link between behavior and disease. It is believed that the type of information measured by our scales is more closely related to behavior changes sought in contemporary cardiovascular disease prevention trials. Results of ANOVA used to test differences in knowledge by ethnicity and sex indicate strong main effects for ethnicity among both children and adults. However, sex was not consistently related to knowledge, except for the general tendency of males to be more knowledgeable about exercise. Step-wise and simultaneous-entry multiple regression were used to test a subset of variables, including sex, education, self-efficacy, acculturation (for Mexican-Americans), and parental health knowledge (for children) as determinants of health knowledge. Education was the strongest predictor for Anglo-American adults, and acculturation level was the strongest for Mexican-American adults. Among children, the only statistically significant variable was parental acculturation level for Mexican-Americans. The scales were found to be useful in measuring differences in knowledge across cultural/linguistic groups and to clearly identify marginally acculturated Mexican-Americans as being least aware of health-behavior knowledge. Implications are discussed.

Acculturation↗

Salvage chemotherapy of advanced lymphoma with investigational drugs: mitoguazone, gallium nitrate, and etoposide.

Patients with advanced lymphoma who relapse from intensive first-line combination chemotherapy generally have a very poor prognosis. The use of investigational drugs which lack cross-resistance to agents commonly used for initial therapy represents an important approach to the management of such patients. Based upon our prior experience, we developed a protocol which employed a combination of three new agents. Mitoguazone (600 mg/m2) was administered on Days 1 and 10; etoposide (100-125 mg/m2) was administered on Days 2, 3, and 4; and gallium nitrate (300 mg/m2/day) was administered as a continuous iv infusion over 24 hours on Days 1-7. Treatment cycles were repeated every 3-4 weeks pending tolerance to toxic reactions. Forty-two patients are evaluable for response (35 with non-Hodgkin's lymphoma and seven with Hodgkin's disease). All patients had received extensive prior treatment (median of two previous chemotherapy regimens). Less than one-half of patients had achieved complete remission (CR) with previous therapy. Twenty-two patients (52%) showed major antitumor responses (five CR, 17 partial). All patients who achieved CR had diffuse large cell lymphoma. Two patients in CR relapsed in the CNS. The median duration of response for patients who achieved partial response was 4 months (range, 1-11+). Major toxic reactions included myelosuppression, optic neuritis, mucositis, and corneal keratitis or conjunctivitis. This combination of experimental agents has major therapeutic activity in patients with advanced, resistant lymphoma. Optimal application of these drugs may be obtained by use as one arm of an intensive program of alternating non-cross-resistant regimens.

Adult↗

Differences in Ca2+ entry blockers revealed by effects on adenosine- and adrenergic- receptors and cyclic AMP levels of [2-3H]adenine-prelabeled vesicles prepared from guinea pig brain.

Three major classes of Ca2+ entry blockers, classified according to effects on cardiac and vascular smooth muscle, were tested. Vesicles prepared from cerebral cortex and stimulated by adenosine and epinephrine constituted adenosine and alpha-adrenergic receptor systems respectively. Vesicles prepared from cerebellum and stimulated by epinephrine constituted the beta-adrenergic receptor system. Experiments with adenosine were also performed with vesicles formed or incubated in the absence of exogenous Ca2+. The results indicate that Ca2+ entry blockers had a variety of effects, even within classes of drugs. Vascular-selective group A Ca2+ entry blockers such as nifedipine and nisoldipine antagonized adenosine, but the structurally-related drug nitrendipine was inactive. Inhibition was competitive with adenosine and independent of exogenous Ca2+. In contrast to receptor-binding studies requiring high ratios of the drugs to adenosine receptor radioligands, nifedipine and nisoldipine were inhibitory at equimolar concentrations with adenosine. Non-selective group A Ca2+ entry blockers such as diltiazem and verapamil were inactive against adenosine. Group B Ca2+ entry blockers, prenylamine and perhexilene, increased cyclic AMP (cAMP) levels of vesicles stimulated by adenosine but not by epinephrine or under basal conditions. This effect was observed only in vesicles that had been formed in the presence of Ca2+. Ca2+ entry blockers also exhibited effects on adrenergic receptors unrelated to effects on adenosine. Verapamil and prenylamine acted as alpha-adrenergic antagonists and only prenylamine acted as a beta-adrenergic antagonist. However, the vesicle system also revealed indirect blocking actions of nifedipine on adrenergic receptor systems. The actions of the Ca2+ entry blockers are discussed in relation to the special usefulness of nifedipine in the treatment of patients with defective atrioventricular conduction and also in relation to the unique ability of group B Ca2+ entry blockers to selectively inhibit Ca2+ and calmodulin activated phosphodiesterase. However, some caution must be applied in drawing conclusions relating to the cardiovascular actions of these drugs from data generated in a neuronally-derived model.

Adenine↗

San Diego family health project: reaching families through the schools.

This project tests the effectiveness of a family-based health behavior change intervention in two ethnic groups. The aim is to help family members initiate and maintain dietary and physical activity behaviors believed to be linked to risk factors for cardiovascular disease. This paper describes the project and the baseline results. Twelve San Diego elementary schools were randomly assigned to intervention or control conditions. Hispanic and Anglo families with a fifth or sixth grade child were recruited to participate in a two-year study. The intervention emphasizes enjoyable experiences designed to transmit knowledge and skills required for long-term changes in diet and physical activity habits. Groups of families met at schools for 12 weekly sessions and six maintenance sessions distributed throughout the following nine months. Outcome behavioral and physiologic measures will be collected at baseline, three months, 12 months, and 24 months. Differences between Anglo and Mexican-American subjects justify targeted activities specific to these groups.

Adult↗

Responses of male and female physicians to medical complaints in male and female patients.

Workups by male and female physicians in response to five common complaints in a sample of 200 men and women-100 married couples-revealed no significant differences in the extent and content. This study contrasts with observations made in a previous study of male physicians who were found to perform more extensive workups for men than for women. The present study differs from the previous one in several respects, however: (1) the physicians are significantly younger, (2) the patients are significantly older, (3) the physicians practice in a prepaid health maintenance organization as opposed to a fee-for-service group, and (4) the practice consists of men and women partners. If the first and last factors are the most important in accounting for the present observations, it is possible that whatever sexist behavior exists will decline with the infusion of young physicians-both men and women-into the evolving medical practice setting.

Adult↗

Renal transplantation in diabetic patients: the end result does justify the means.

There were 49 insulin-dependent diabetics who received 52 renal allografts: 13 from living related and 39 from cadaveric donors. The mean age and time on dialysis were similar for both recipient groups. Patient survival at 1 and 2 years was 100 per cent for living related donor recipients, and 76 and 56 per cent at 1 and 2 years for cadaveric recipients. Renal allograft survival was 92 and 85 per cent at 1 and 2 years for living related donor recipients. Cadaveric allograft survival was 49 and 41 per cent at 1 and 2 years. The cumulative mortality rate was 39 per cent and the over-all surgical morbidity was low. Renal transplantation in diabetic patients is worthwhile from the standpoint of patient and allograft survival.

Adult↗

Urologic complications in 505 renal transplants with early catheter removal.

Of 505 consecutive renal transplants urologic complications occurred in 4.1 per cent of cadaver, 2.6 per cent of living related, 1.9 per cent of diabetic and 3.8 per cent of nondiabetic allografts. Over-all, patient survival and graft salvage rates were 94 and 83 per cent, respectively. Principles of prevention, diagnosis and management of these complications are discussed. In contrast to prior standards the bladder catheter was removed within 36 hours postoperatively in nearly all cases without any increase in morbidity.

Graft Survival↗

Disease due to cytomegalovirus and its long-term consequences in renal transplant recipients. Correlation of allograft survival with disease due to cytomegalovirus and rubella antibody level.

We prospectively studied 52 consecutive renal allograft recipients who retained their grafts at least three months. The transplant recipients were observed for five years or longer. Disease due to cytomegalovirus (CMV) occurred in nine (17.3%). Manifestations of disease due to CMV that were significantly more common than in chronologically matched controls in comparable periods after transplantation included fever, leukopenia, hepatic function abnormalities, pneumonia, and renal dysfunction. Life-table analyses suggested a trend of decreased allograft survival with disease due to CMV, but the difference between controls was not statistically significant. A significant inverse correlation were noted between the level of hemagglutination inhibition antibody to rubella virus reached after transplantation and allograft survival. This correlation remained statistically significant even when patients with disease due to CMV were excluded from the analysis.

Actuarial Analysis↗

Surgical correction of posttransplant renovascular hypertension.

The incidence of renovascular hypertension in the transplanted kidney is reported to range between 5 and 15%. A review of 391 consecutive renal transplant patients revealed 16 patients (5.4%) with hypertension secondary to partial obstruction of renal arterial blood flow. The clinical course of this group of patients was marked by early normotension followed by progressive diastolic pressure elevation, with improving renal function and loss of accumulated excess volume. Five etiologic factors are responsible for impaired arterial flow in this group of patients. Indication for operation was based on hypertension and/or impaired renal function. Patch angioplasty using saphenous veins was the procedure of choice in most instances. The average blood pressure was 185 mmHg; systolic/125 mmHg; diastolic preoperatively, compared with 140 mmHg; systolic/90 mmHg: diastolic postoperatively. Twelve of 16 patients had good results, and improvement in renal function was observed in eight patients. Serum renin levels did not correlate well with the operative findings. The use of meticulous technique, combined with maximum use of autogenous tissue, is emphasized.

Blood Pressure↗

Hyperglucagonemia in uremia: reversal by renal transplantation.

Chronic renal failure in man is associated with hyperglucagonemia that is not corrected by hemodialysis. Plasma glucagon concentrations were measured in nine patients before and after renal transplantation. Mean plasma glucagon concentration in eight patients with chronic renal failure before transplantation was 295 plus or minus 171 pg/ml (plus or minus SD). After successful transplantation, mean plasma glucagon concentration fell to 134 plus or minus 81 pg/ml (plus or minus SD) (P less than 0.001). Plasma glucagon concentration remained elevated in an additional patient who received a cadaveric graft that never functioned. Immunologic rejection of transplanted kidneys was associated with a dramatic increase of plasma glucagon concentration.

Cadaver↗