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Biomedical subjects

J Alexander

Publications and source records attributed to J Alexander.

At least 523 records · Page 29Linked to original sources
PubMed1984

Haemolytic activity of copper as influenced by chelating agents, albumine and chromium.

The haemolytic activity of CuSO4 (0.3 mM) in vitro was reduced in the presence of albumine (5-20 g/l). The presence of D-penicillamine, triethylene tetramine or dimercaptosuccinic acid (0.3 mM) also reduced the copper-induced haemolysis, whereas 2,3-dimercaptopropane-1-sulphonate increased the cytolysis. N-ethylmaleimide (NEM) in appropriate concentrations (1 mM), as well as chromic chloride (0.3 mM), reduced the copper-induced haemolysis. Higher concentrations of NEM (2 mM) were ineffective. The results may provide helpful suggestions as regarding the clinical treatment of copper poisoning and Wilson's disease. The results may also be helpful for the understanding of the mechanisms of haemolysis associated with copper intoxication in vivo.

Adult↗
PubMed1984

The use of phenothiazines to enhance the rectal absorption of water-soluble compounds.

The ability of phenothiazines to enhance the rectal absorption of sodium cefoxitin and gentamicin sulphate from aqueous formulations was examined in rats. In the absence of absorption-promoting adjuvants, sodium cefoxitin and gentamicin sulphate bioavailabilities from the rectal compartment were less than 5% of the corresponding intravenous administration. In aqueous microenemas containing 20 mg ml-1 phenothiazine, sodium cefoxitin bioavailability increased to 16-62%, while gentamicin sulphate bioavailability increased to 74-146%. The absorption-promoting potential of chlorpromazine and perphenazine was concentration-dependent, with significant increases in gentamicin sulphate absorption occurring with 1 mg ml-1 chlorpromazine or 2.5 mg ml-1 perphenazine. Maximal gentamicin sulphate bioavailability and serum concentrations were achieved with 10 mg ml-1 chlorpromazine or 20 mg ml-1 perphenazine. The findings indicate that the phenothiazines, which are well absorbed rectally, also significantly enhance the rectal absorption of water-soluble, poorly absorbed compounds.

Animals↗
PubMed1984

The financial characteristics of hospitals under for-profit and nonprofit contract management.

In this assessment of the financial characteristics of a large sample of contract-managed hospitals compared with traditionally managed hospitals, emphasis was given to differences between hospitals managed by for-profit and nonprofit organizations and between hospitals before and after they were contract managed. Our findings suggest higher profitability for hospitals managed by nonprofit organizations in light of their poor profitability prior to contract management and better activity ratios for for-profit managed hospitals. These and other findings are discussed in terms of their implications for both hospital administrators and researchers.

Capital Expenditures↗
PubMed1983

Prodrugs of 6-thiopurines: enhanced delivery through the skin.

Soft-alkylated derivatives of 6-mercaptopurine, its riboside, and 2-amino-6-mercaptopurine riboside have been prepared and evaluated to improve the delivery of the thiopurines through the skin. The soft-alkylated derivatives were prepared by the alkylation of the thiopurines with acylheteroalkyl halides under neutral or basic conditions. The penetration of the derivatives through hairless mouse skin was measured using diffusion cells. All of the derivatives underwent extensive degradation during their diffusion through skin so that the parent thiopurine, even in the case of the ribosides, was the major product observed in the receptor phase. The pivaloyloxymethyl derivatives showed the greatest potential for enhancing the penetration of the thiopurines through the skin. Among the 6-mercaptopurine derivatives, VII and XI were the most effective; they delivered 5 and 13 times, respectively, more 6-mercaptopurine than 6-mercaptopurine itself.

Animals↗
PubMed1983

Serial radionuclide assessment of doxorubicin cardiotoxicity in cancer patients with abnormal baseline resting left ventricular performance.

While previous studies have demonstrated that sequential radionuclide angiocardiography allows identification of patients at risk for development of congestive heart failure and prediction of the appropriate time for safe discontinuation of doxorubicin, these studies were based predominantly on patients with normal baseline left ventricular performance. This study addresses the use of doxorubicin in patients with abnormal left ventricular ejection fraction (less than 55%) prior to drug administration. Of 337 patients referred for evaluation of left ventricular performance prior to doxorubicin therapy during a 36-month period, 45 (13%) had abnormal baseline left ventricular performance determined by first-pass radionuclide angiocardiography. Sixteen patients had antecedent cardiovascular disease, and 16 patients had received thoracic radiation, while only four patients had both. Left ventricular ejection fraction in each of these subgroups was comparable. In 7 of 16 patients who only had a baseline determination of left ventricular function, doxorubicin was not administered because of a significant concern for the potential risk of doxorubicin cardiotoxicity. In the group of 29 patients followed sequentially over 3 to 15 months (mean, 6 months), there was no significant difference between baseline and final left ventricular ejection fraction (48 +/- 5 vs 47 +/- 9%, p = NS). Only in the 12 patients who received greater than or equal to 350 mg/m2 cumulative dose was there a small but significant fall in left ventricular ejection fraction (48 +/- 4 vs 43 +/- 8%, p less than 0.05). Only one patient developed congestive heart failure. This study demonstrates that doxorubicin can be administered safely to patients with abnormal baseline left ventricular performance using serial radionuclide studies as a means of monitoring therapy. Guidelines for doxorubicin therapy in these patients have been developed.

Adolescent↗
PubMed1983

Results of changing trends in the surgical management of complications of diverticular disease.

During the past decade, primary resection with anastomosis has gained acceptance in the surgical treatment of complications arising from diverticular disease of the colon. We have reviewed our experience during the past 10 years to determine whether this approach has clinical validity. Of 673 patients followed over a 10-year period, 93 (14%) required operation. Operative indications were generally limited to urgent complications of the disease: abscess (36), bleeding (18), perforation (10), obstruction (10), and fistula (5). A small group of patients underwent operation for recurrent symptoms (7) and for the suspicion of coexistent carcinoma (8). Initial operative management included resection with anastomosis (44), resection and colostomy (26), and diverting colostomy (23). The overall incidence of complications was significant; the most common complication was infectious in nature: abscess (7), fistula (9), wound infection (11), dehiscence (2), and sepsis (5). Complications were more numerous in patients who did not receive primary resection of the diseased segment 2.1 versus 1.1 complications per patient, respectively), and the duration of hospitalization was significantly greater in this group as well. The perioperative mortality rate of our surgical patients was 6.4%; none of these deaths were associated with resection and anastomosis. These data indicate that resection with primary anastomosis is a sound approach in properly selected patients with urgent complications of diverticular disease, and that aggressive surgical management can yield results that are better than those obtained from the use of colostomy alone.

Adult↗
PubMed1982

Patient-initiated therapy for recurrent genital herpetic infections.

Therapy for recurrent genital herpes is difficult to evaluate because of the short duration of lesions and viral shedding. Very early treatment, however, can be begun by patients who experience prodromes before onset of lesions. We have found prodromes to occur in 73 percent of male and 84 percent of female patients; 57 percent of the men and 68 percent of the women experienced prodromes in at least three out of every four recurrent episodes. Variables that might affect results of such a patient-initiated study evaluating topical acyclovir included: application of the ointment (drug or placebo) without prodrome (10 percent); the possibility of a false prodrome (less than or equal to 10 percent); long intervals between experiencing a prodrome and ointment application (15 percent greater than 24 hours); the inability to sense a prodrome during sleep; lack of ointment application to the involved areas with initial or later lesions (approximately 15 percent); noncompliance of enrollees in returning for study evaluations (greater than or equal to 10 percent). Such variables will need to be considered when the code is broken in this multicenter study, as well as for patient-initiated studies with other formulations of acyclovir or with other drugs. Earlier negative studies with other agents given within two to three days of appearance of lesions might also require reevaluation with similar patient-initiated studies.

Acyclovir↗
PubMed1982

Combination chemotherapy of esophageal carcinoma using cisplatin, vindesine, and bleomycin.

Sixty-one patients with epidermoid carcinoma of the esophagus have been treated with a three drug combination of cisplatin, vindesine, and bleomycin. Of 53 patients currently evaluable for response, 29 (55%) have had partial remissions: 7/16 with metastatic, and 22/37 with local-regional disease. The median duration of response in metastatic patients is eight months. Of 28 patients treated preoperatively, 23 (82%) had resectable disease. The major toxicities seen were nephrotoxicity and myelosuppression. Cisplatin, vindesine and bleomycin is an effective combination in the treatment of esophageal carcinoma. Effects on long-term survival cannot yet be evaluated.

Acute Kidney Injury↗