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Biomedical subjects

T Parker

Publications and source records attributed to T Parker.

At least 73 records · Page 4Linked to original sources
PubMed1988

Sexual expression of mentally retarded people: educational and legal implications.

Issues of legal consent and competency, in addition to the relevant psychological literature, were reviewed in relation to institutional policy for sexual management of mentally retarded individuals. The significance of comprehensive sex education was also discussed. Finally, suggestions were provided that minimize prejudicial treatment of mentally retarded people, without eliminating their opportunities for sexual expression.

Education of Persons with Intellectual Disabilitie↗
PubMed1985

Thyroid radiation absorbed dose from diagnostic procedures in U.S. population.

According to a 1981 survey of thyroid imaging methods in the United States, radionuclide thyroid scans and uptake studies increased 250%-300% between 1966 and 1981, while the U.S. population increased only 17%. Collective absorbed dose decreased from 18 X 10(6) rad (18 X 10(4) Gy) in 1966 to 13.9 X 10(6) rad (13.9 X 10(4) Gy) in 1981. The decrease was due to the use of iodine 123 and technetium 99m pertechnetate rather than iodine 131 (I-131 was used for 100% of scans and uptake studies in 1966 and 10% and 54%, respectively, in 1981) and also to fewer free-standing thyroid uptake studies (150,000 in 1966 and 33,000 in 1981). Even with reduced usage, I-131 still accounted for 93% of the collective absorbed dose in 1981. If I-131 were eliminated from diagnostic procedures, the annual absorbed dose would decrease to 1.4 X 10(6) rad (1.4 X 10(4) Gy). The number of radiation-induced cancer cases would also be reduced.

Humans↗
PubMed1985

Phrenic nerve paresis associated with the use of iced slush and the cooling jacket for topical hypothermia.

Phrenic nerve injury has been reported with the use of iced slush for topical cardiac hypothermia. To study this problem in both valve and coronary procedures, we tried to detect phrenic nerve injury in five groups of patients undergoing cardiac operations in which different techniques of topical hypothermia were used. The results indicate a 24% incidence of left phrenic nerve paresis in patients undergoing coronary bypass with iced slush used for topical hypothermia, 12.5% in patients in whom the cardiac cooling jacket was used in association with cold saline, and 22.9% in patients in whom both the cardiac cooling jacket and iced slush were used in the pericardial sac. There was no phrenic nerve injury when saline alone was used. Phrenic paresis is transient and of no clinical significance except when bilateral. Avoidance of contact of either the cooling jacket or iced slush with the phrenic nerve could avoid this complication.

Cold Temperature↗
PubMed1982

Further validation of the plasma isotope ratio method for measurement of cholesterol absorption in man.

Recently we evaluated an isotope ratio method (IRM) for measurement of cholesterol absorption in 14 patients (15 experiments) hospitalized in the metabolic ward by comparing it to simultaneous measurements with a fecal radioactivity method (FRM) and found good to excellent agreement between two procedures (Samuel, P., J. R. Crouse, and E. H. Ahrens, Jr. 1978 J. Lipid Res. 19: 82-93). This comparison has now been extended to additional studies carried out in eight hospitalized patients (19 experiments). Of the 34 comparisons between the IRM and the FRM in our hands, 29 were technically acceptable (chromic oxide fecal recovery >/=80%): percent cholesterol absorption was 43.1 +/- 12% by the FRM and 46.0 +/- 11% by the IRM, exhibiting an accuracy within 3.5% at the 95% and 4.7% at the 99% confidence levels. In addition, various procedural modifications of the IRM were studied in out-patients. The measurement of isotope ratios in a single blood sample (analyzed in sextuplicate) on the third day (or later) following the tests gave identical results to those obtained from six to eight daily blood samplings. Blood samples drawn at any time during the day gave cholesterol absorption values similar to those obtained from samples drawn following an overnight fast. Absorption tests carried out before and 1 hr after breakfast, lunch, or dinner, or giving the oral isotope in three divided daily doses all yielded identical results with tests carried out in the am in the fasting state. Cholesterol absorption was markedly reduced when the oral radiolabeled cholesterol was administered in orange juice vs. liquid formula, milk or a solution of glucose and amino acids, consistent with the well-known fact that gallbladder contraction is a critical requirement of cholesterol absorption. A meal high in cholesterol consumed on the day of the test did not influence the results of the absorption measurements. Furthermore, addition of three eggs per day (~750mg cholesterol) for 3 weeks to a low-cholesterol poly-unsaturated fat diet caused no significant change in percent cholesterol absorption in any of eight patients. We conclude that the isotope ratio method accurately and precisely measures cholesterol absorption in man, and that it is suitable not only for in- but also for out-patient studies.-Samuel, P., D. J. McNamara, E. H. Ahrens, Jr., J. R. Crouse, and T. Parker. Further validation of the plasma isotope ratio method for measurement of cholesterol absorption in man.

Absorption↗
PubMed1980

The role of vagotomy in pancreaticoduodenectomy.

In a series of 41 pancreatoduodenectomies the Whipple procedure was done in 27 patients and total pancreatoduodenectomy in 14 others with two postoperative deaths. Among 39 survivors, seven developed evidence of stomal ulcer 20 days to six years after operation; details of their courses are summarized. Proven stomal ulcer occurred in five of 14 patients who did not have concomitant vagotomy with pancreatoduodenectomy (36%). Each of these required vagotomy secondarily in management. When two patients with hematemesis in whom stomal ulcer was suspected but not proven are included, the incidence of stomal ulcer in nonvagotomized patients with pancreatoduodenectomy (7/14) is 50%. There were no stomal ulcers in patients with pancreatoduodenectomy who had concomitant vagotomy (0/25). It is logical to add the protective effects of vagotomy to pancreatoduodenectomy, especially when the disease process favors prolonged survival.

Adenocarcinoma↗
PubMed1980

Urea synthesis by perfused rat liver in experimental uremia.

Urea synthesis was examined in experimental uremia using the isolated perfused rat liver in order to assure strict control of substrate (NH4Cl) presented to the liver. Acute uremia was created in female Sprague-Dawley rats by bilateral nephrectomy (n = 7) 48 h prior to studies. Chronic uremia (8--14 weeks) was produced by right nephrectomy and segmental infarction of the left kidney in 7 rats. At infusion rates of NH4Cl (8.3 mumol/min) which resulted in prehepatic perfusate ammonia levels approximately twice the previously described Km value, livers of chronically uremic rats had slightly higher rates of urea production than controls (controls: 0.41 +/- 0.03; chronic uremia: 0.54 +/- 0.04 mumol/min/g of wet liver weight; p less than 0.02). In acute uremia, urea production was higher (0.66 +/- 0.05 mumol/min/g) than in sham-operated rats (0.59 +/- 0.05 mumol/min/g) but the differences did not achieve statistical significance. Simultaneously performed taurocholate transport studies did not reveal significant functional differences between the livers of uremic and control animals. The data suggest that urea production by livers of uremic rats is increased when compared to that of control animals.

Acute Disease↗
PubMed1979

Prostaglandins V (1). Synthesis and pharmacology of (+/-)-11-deoxy-10-hydroxyprostaglandin E1 methyl ester.

(+/-)-Deoxy-10-hydroxy-PGE1 methyl ester (Va) has been synthesised via conjugate addition of the cuprate (III) to the 5-tetrahydropyranyloxycyclopentenone (IId). Va was found to be 0.1 times as active as PGE1 as a uterine stimulant in the anaesthetized pregnant rat, 0.25 times as active as PGE1 in causing vasodepression in the anaesthetized cat, and approximately equiactive to PGE1 in inducing bronchoconstriction.

Alprostadil↗
PubMed1978

The ultrastructure of mouse testicular interstitial tissue containing plutonium-239 and its significance in explaining the observed distribution of plutonium in the testis.

The technique of autoradiography with Araldite-embedded sections was used to study the distribution of 239Pu in mouse testis at various times post-injection. Adjacent sections were examined with both the light microscope and electron microscope. The autoradiographs showed that from 1 week to 3 months postinjection, most 239Pu in located in interstitial tissue. The major change in distribution observed was that the early diffuse deposit in interstitial tissue is concentrated in macrophages with increasing time post-injection. This is a real change of distribution as the amount of 239Pu in mouse testis remains constant from 1 week to 3 months post-injection. Study of the ultrastructure of interstitial tissue indicated that the accumulation of 239Pu in macrophages may be brought about in two ways. First, there may be phagocytosis of dead cells containing 239Pu. Second, 239Pu may follow the transfer of waste products of hormone synthesis from Leydig cells into macrophages. The significance of these observations is discussed with regard to the deposition of 239Pu in human testis.

Animals↗
PubMed1978

Schooling, environment, and cognitive development: a cross-cultural study.

The purpose of this study was to investigate the influence of schooling and general environmental conditions on the development of memory and cognitive skills in young children. The subjects were 824 5- and 6-year-old children living in jungle villages and in slum settlements of Lima, Peru. Half of the children in both the jungle and city were Mestizo, and half were Quechua Indians. Some 6-year-olds of each cultural group and in each location attended school; others did not. Memory tasks were presented in different modes of representation, that is, verbal, pictorial, and enactive; and cognitive tasks in "concrete" and "abstract" versions. A sample of parents in each group was interviewed concerning environmental conditions. In addition, samples of upper-middle-class children in Lima and poor children in Detroit were tested to assess the generality of the findings. Attendance at school was related to improvement in performance on all tasks. Improvement was equivalent for both locations, both cultural groups, and each social class. Attendance at school also was accompanied by reduced within-group variability on some tasks and by greater differentiation of cognitive processes within children. Location and cultural group interacted differentially by task according to a complex pattern of relations. There were no indications that the organization of memory or cognitive processes differed as a function of social class, age, location, or cultural group. The results were interpreted in terms of children's opportunities to acquire specific memory and cognitive skills from schooling and from their general experience in a particular environment.

Age Factors↗