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Biomedical subjects

P Sullivan

Publications and source records attributed to P Sullivan.

At least 253 records · Page 14Linked to original sources

Gentamicin nephrotoxicity. II. Physiological, biochemical and morphological effects of prolonged administration to rats.

The purpose of this investigation was to determine the morphological, physiological and biochemical effects of gentamicin upon the rat kidney following prolonged administration of the antibiotic. Sprague-Dawley and Fischer 344 strain rats were given 3, 10, 20 or 40 mg gentamicin per kg body weight per day for 28 days. Morphologic alterations were evaluated by light and electron microscopy. Functional parameters included glomerular filtration rate, PAH secretion, renal plasma flow, sodium reabsorption, potassium excretion, urine volume and protein, and serum urea nitrogen. Oxidative metabolism of mitochondrial fractions from renal cortical homogenates was evaluated by oxygen uptake and P:O ratios. The results indicate focal proximal tubular injury, decreased tubular maximum secretion of PAH, and altered oxidative metabolism at the higher dose levels of gentamicin. Neither elevations of serum urea nitrogen nor alterations in glomerular filtration rate, renal plasma flow, or sodium or potassium excretion were observed. Thus, it appears that high dose levels (40 mg per kg per day) alter the structure and function of some proximal tubular segments when administered over prolonged periods. The alterations appear reversible. Although nephro-toxicity is identified under these conditions in rats, extrapolation to human patients usually receiving much lower doses must be guarded.

Animals↗

Diarrhea of travelers to Mexico. Relative susceptibility of United States and Latin American students attending a Mexican University.

A clinic was established at Universidad de las Americas, Cholula, Puebla, Mexico for the study of acute diarrhea rates in newly-arrived students and full-time students. Diarrhea occurred in 22 of 55 newlly-arrived U.S. summer students (40%), compared to 28 of 142 U.S. full-time students (20%), 4 of 29 Venezuelan summer and full-time students (14%) and 7 of 66 Mexican full-time students (11%) (the differences were significant, p less than 0.005). Recurrent episodes of diarrhea during the month of study occurred in 15% of U.S. summer students, 4% of U.S. full-time students, and were non-existent in students from Latin America. As well as the 61 students with diarrhea enrolled in the incidence study, all students who developed diarrhea at the univeristy were encouraged to visit the clinic. This gave a total population of 130 cases of diarrhea. The illness that developed in students form the U.S. varied widely, but it typically consisted of seven to 13 unformed stools during the first 48 hours of illness, with illness persiting three to five days. Illness tended to be more severe in the U.S. students. Fifty per cent of the U.S. students with diarrhea had "severe" illness (greater than or equal to 10 unformed stools in first 48 hours) compared to 23% of the Latin Americans. This study indicates that the agents responsible for diarrhea in Latin America are widespread and that resistance to infection develops after prolonged or repeated exposure.

Diarrhea↗

Location of food consumption and travelers' diarrhea.

Daily food histories for one month were obtained in summer, 1975, from students attending a Mexican university to determine the influence of food consumption on the development and etiology of diarrhea. In newly-arrived students from the U.S. who ate half or more of their meals in the school cafeteria and public restaurants there were significant increases in diarrhea (p less than 0.005); shigella infection (p less than 0.05) and toxigenic E. coli infection (p less than 0.025) compared to the students eating a comparable number of meals in private homes. In the summer U.S. students there was also an association of diarrhea and eating from street vendors (p less than 0.05). In full-time U.S. students who had lived in Mexico a year or longer as well as in Latin American students a relationship between location of meals and occurrence of enteric disease was not apparent. High numbers of enteric bacteria were recovered from food from the school's cafeteria, public restaurants, street vendors and small grocery stores. Shigella were isolated from cooked and uncooked hamburger patties from the school cafeteria. Four shigella carriers were found among kitchen personnel at the school. This study demonstrates that food serves as a major vehicle through which travelers' diarrhea occurs.

Diarrhea↗

Symptomatic treatment of diarrhea with bismuth subsalicylate among students attending a Mexican university.

Students attending a Mexican university who developed diarrhea were randomly treated with bismuth subsalicylate or a placebo. One hundred and eleven were given 30 ml each 1/2 hr until eight doses (total dose of active drug 4.2 g) were given and 58 students received twice this dose (8.2 g of active drug) over the 3 1/2-hr treatment period. The number of unformed stools was significantly decreased in both bismuth subsalicylate treatment groups compared to the placebo controls for the period 4 to 24 hr after therapy. A reduction in diarrhea was additionally noted for the duration of the 48-hr surveillance period for the students receiving the higher dose of active drug. Subjective relief within 24 hr of therapy of the symptoms of diarrhea, nausea, and abdominal pain or cramps was reported with a significantly increased frequency in the bismuth subsalicylate group. The most pronounced effect of the treatment occurred in the United States students with diarrhea who had recently arrived in Mexico. This appeared to be related to the favorable effect of bismut subsalicylate on the course of toxigenic Escherichia coli infection. Students with shigellosis did not experience a prolonged illness in either treatment group.

Bismuth↗

Role of DTIC (NSC-45388) in the chemotherapy of sarcomas.

DTIC was one of the first of several new agents evaluated by the Southwest Oncology Group (SWOG) and the M.D. Anderson Hospital and Tumor Institute (MDAH) in the therapy of adult patients with metastatic sarcomas. It yielded an overall response rate of 17%. This is similar to that seen in a review of 138 patients who represent the total number reported in either published or unpublished data. The subsequent addition of DTIC to adriamycin in several studies carried out at the MDAH and in the SWOG has increased the complete and partial remission rate over that seen with adriamycin alone, and more importantly has increased remission duration and survival. DTIC is currently used in combination with adriamycin in the first-line therapy of patients with metastatic sarcomas and should be considered for patients who have relapsed on primary therapy not including DTIC.

Clinical Trials as Topic↗

Sulfur hexafluoride in owl monkey vitreous cavity.

Sulfur hexafluoride (SF6) gas, tested in the vitreous chamber of owl monkey eyes, remained in the vitreous cavity about twice as long as air (ten to 11 days vs. five to six days). Its volume expanded from the diffusion of other gases into the created gas pocket. Lens opacities developed when the lens was in continuous contact with SF6 or air. Sulfur hexafluoride appeared to be no more toxic to the retina than air, using electroretinographic, histologic, and electron microscopic criteria.

Air↗

Measurement of plasma and tissue triiodothyronine concentration in the rat by radioimmunoassay.

This paper reports a radioimmunoassay method for triiodothyronine (T3) and the application of this assay to the study of plasma and tissue T3 concentration in the rat. Several antisera formed to a T3-bovine fibrogen complex in guinea pigs and T3-thyroglobulin complex in rabbits are shown to have low or no cross reactivity with T4, monoiodotyrosine, diiodotyrosine, tetraiodothyroacetic acid (TETRAC) and reverse T3. Cross reactivity with T3 derivatives, triiodothyroacetic acid (TRIAC), and triiodothyropropionic (TRIPROP) was variable, some antisera differentiating moderately well and others not at all. An extraction method is described which removes approximately 85% of added 125I-T3 or unlabelled T3 from tissues and in the final step represents 57% of total tissue T3. Mean plasma T3 in 5 normal male rats was 58 plus or minus 6.0 ng/100 ml (SEM), in liver 769 plus or minus 56 ng/100 g, and kidney 627 plus or minus 39 ng/100 g. Tissue to plasma concentration gradients for liver and kidney were 13.3 and 10.8, respectively.

Animals↗

The outcome of direct current cardioversion (DCC) for the treatment of atrial fibrillation (AF) in a district general hospital in Ireland.

BACKGROUND: Direct current cardioversion (DCC) is a method to control persistent AF, to facilitate a reduction in stroke risk. Although this is a frequently performed procedure, there are no available published data regarding its outcome in an Irish setting. AIMS: To determine the short- and long-term outcome of DCC, factors predicting a successful outcome, and its safety. METHODS: Data relating to each DCC were collected retrospectively from patient notes over a 6.3 year-period, and subsequently entered into a Microsoft Access database before subsequent statistical analysis. RESULTS: Forty-five consecutive unselected patients were identified, in which 59 DCCs were performed. Sinus rhythm (SR) was achieved immediately after DCC in 54/59 (91%) patients. There was a significant positive correlation between patient body weight and the energy level required to achieve SR (p=0.0001). No thromboembolic complications were noted. After a mean follow-up time of 12 +/- 13.7months, 30/45 (67%) had maintained SR. After univariate analysis, a number of important factors predictive of maintenance of SR at follow-up were identified. CONCLUSION: DCC was found to be an effective method for short- and long-term control of AF, without thromboembolic complications, and patients with a favourable long-term outcome after DCC could conceivably be predicted on the basis of a methodical history, careful examination, simple investigations and pharmacological variables.

Atrial Fibrillation↗