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Biomedical subjects

B Frank

Publications and source records attributed to B Frank.

At least 91 records · Page 5Linked to original sources

The dean's job satisfaction: its relationship to organizational structure.

The purpose of this study was to explore the relationship between formal organizational structure and the dean's job satisfaction. A two-part questionnaire was sent to 345 deans of Baccalaureate and Higher Degree nursing programs. Seventy-three percent responded. The findings showed that decentralization and some degree of complexity and formalization were related to job satisfaction. In spite of these findings, deans should consider all personnel, academic, and budgetary implications before proceeding with organizational restructuring.

Administrative Personnel↗

Intestinal uptake and release of cobalamin complexed with rat intrinsic factor.

The mechanism of uptake of intrinsic factor (IF) and cobalamin (Cbl) by enterocytes and their subsequent fate have been uncertain. To examine this problem double-labeled IF X Cbl was added to small intestinal organ cultures. When 125I-IF X [57Co]Cbl was added to rabbit ileal explants, binding and internalization increased linearly for 24 h. After an 18-h chase with nonlabeled IF X Cbl, no 125I-IF returned to the cell surface. An amount of 35-45% of the internalized Cbl was found free, not bound to IF or any other protein. About 60% of both internalized ligands was bound to membranes but by a non-Ca2+-dependent bond, suggesting binding to a protein other than the brush-border receptor. Cobalamin was released from IF at pH 5.0 to the same degree (30%) as free Cbl was found inside the cell (35-45%). Neither pancreatic proteases nor ileal homogenates effected release of Cbl from IF. When cathepsins were added, the Cbl released was no greater than could be attributed to pH 5.0 alone. Chloroquine added to tissue explants did not alter the percentage of free intracellular Cbl. From these results we suggest that IF X Cbl is internalized and detached from the receptor within the enterocyte. The mechanism of release is not known but seems to require an acid pH (5.0). The Cbl is released in the mucosa, perhaps when the IF X Cbl complex enters a nonlysosomal cellular compartment with an acidic environment. There is no substantial recycling of IF to the brush-border membrane.

Animals↗

Telephone surveying for drug abuse: methodological issues and an application.

In light of New York State's experience, it is probable that future household drug use surveys will use telephone administration. Drug use questions are not as sensitive as had been thought, and are easily administered by telephone. In addition, the lower costs, the computer-assisted capabilities, and the saving in time are some of the advantages in comparison to face-to-face surveying. In order to address the nontelephone segments of the household population--despite their declining proportion--and to improve response rates, mixed-mode interviewing may have to be considered. Given a better understanding of telephone-associated behavior and the increasing popularity of technological advances, such as the portability and mobility of phones, telephone surveying may become even more attractive in the future.

Cross-Sectional Studies↗

Morphometric studies of the hamster flank organ: an improved model to evaluate pharmacologic effects on sebaceous glands.

The Syrian golden hamster flank organ, composed of clusters of large sebaceous glands, has been used to investigate effects of systemically or topically applied hormones, antiandrogens, and retinoids. Accurate assessments of flank organ sebaceous gland volume and its correlation with in vivo measurements of flank organ size have not been reported. Sixty flank organs were examined. In vivo flank organ size was expressed as the product of the greatest longitudinal (DL) and greatest transverse (DT) diameters of the palpable bulk. Sebaceous gland volumes were calculated from planimetric analyses of serially sectioned specimens of flank organs using a computer-assisted planimetry system. In vivo measurements (DL X DT) were found to correlate with planimetrically determined flank organ volume. Planimetric analysis of every 10th section of a serially sectioned flank organ was almost as sensitive as analysis of every section in determining sebaceous gland volume. Computer-assisted planimetry of serially sectioned flank organs was found to be an accurate and reproducible method for assessing gland volume. In vivo measurements of the palpable bulk are a good indicator of sebaceous gland size and correlate well with planimetrically determined sebaceous gland volumes.

Animals↗

Biosynthetic human insulin and proinsulin have additive but not synergistic effects on total body glucose disposal.

Recent studies from our laboratory have demonstrated that human biosynthetic proinsulin has a much slower MCR than insulin as well as a greater effect on hepatic than on peripheral tissues. Since both of these features make proinsulin potentially useful as an adjunct to insulin, the present study was undertaken to characterize the biological effects of combined infusions of insulin and proinsulin. As an initial study, multiple euglycemic clamp studies were performed in six normal subjects to construct dose-response curves for insulin- and proinsulin-mediated glucose disposal. Insulin infusion rates of 0.63, 1.67, 5, and 10 micrograms/M2 X min were compared to proinsulin infusion rates of 2.75, 7.5, 22.5, and 45 micrograms/M2 X min. Analysis of these dose-response curves indicated that proinsulin-mediated glucose disposal was approximately 7% that of insulin. Each subject also received a combined infusion of insulin (0.63 micrograms/M2 X min) and proinsulin (2.75 micrograms/M2 X min). The mean (+/- SE) glucose disposal rate obtained during the combination study (319 +/- 21 mg/M2 X min) was similar to that predicted by adding the results from the individual hormone infusions (307 +/- 21 mg/M2 X min). Analysis of the dose-response curves for insulin and proinsulin was also useful in predicting the glucose disposal rate during the combination study (290 +/- 19 mg/M2 X min). Thus, using either approach to predict the glucose disposal rates, insulin and proinsulin appeared to have additive effects on total body glucose disposal.

Adult↗

An overview of substance use among New York State's upper income householders.

A 1981 survey of substance use among household residents in New York State found rates of use consistently higher among the upper income group ($50,000 and over) than among groups with lower incomes. In addition, measures of the seriousness of the problem also revealed higher rates among the upper income group than the other income groups. In terms of preferences for treatment, the upper income group substance user clearly opts for the private professional. The findings generally suggest that there are few qualitative differences in patterns of substance-taking among the income groups, and it might be hypothesized that the availability of disposable income in the upper income group and some situational factors may facilitate that group's substance-using behavior.

Data Collection↗

The effects of biosynthetic human proinsulin on carbohydrate metabolism.

Large quantities of biosynthetic human proinsulin have recently become available through recombinant DNA technology. Since the in vivo effects of human proinsulin have not been studied in man, we compared the dose-response relationship for stimulation of glucose disposal and suppression of hepatic glucose output by proinsulin and insulin. Ten normal subjects were studied using the euglycemic glucose clamp technique. The human proinsulin and insulin infusion rates were chosen to achieve steady-state proinsulin levels 10-fold higher than insulin levels on a molar basis, based on previous observations that porcine proinsulin has approximately 10% the potency of insulin. Proinsulin infusion rates of 2.75, 7.5, 22.5, and 45 micrograms/m2/min were compared with insulin infusion rates of 0.63, 1.67, 5, and 10 micrograms/m2/min. Primed, continuous infusions of insulin yielded steady-state levels within 25 min, whereas proinsulin levels did not reach a steady state for 120-180 min. The metabolic clearance rate of insulin was 11-12 ml/kg/min at the lower infusion rates but fell to 8.4 ml/kg/min at the highest infusion rate. The metabolic clearance rate of proinsulin was 3.0-3.5 ml/kg/min at all infusion rates. Dose-response analysis demonstrated that proinsulin-mediated glucose disposal was approximately 8% that of insulin. In contrast, proinsulin-mediated suppression of hepatic glucose output was approximately 12% that seen with insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Axon end-bulb swellings and rapid retrograde degeneration after retinal lesions in young animals.

After making a lesion of the retina, anterograde (Wallerian) and retrograde degeneration of optic axons occurred more rapidly in newborn mice than in adults. Axon sprouting occurred only in adult mice, perhaps because retrograde degeneration may have been too rapid and severe for sprouting to occur in newborns. Retinal lesions in mice of any age produced end-bulb swellings initially on both sides of the lesion. In all animals, dense packing of lysosomes and other organelles occurred in end-bulbs on the side of Wallerian degeneration but did not occur in end-bulbs on the retrograde side, where accumulation of smooth endoplasmic reticulum was the most characteristic change. Retrograde end-bulbs appeared much like growth cones, which sprouted in adults, but degenerated in younger animals. Continuing daily enlargement of end-bulb swellings was noted on the Wallerian side of lesions in adults, but not in newborns. Such enlargement is believed to have resulted from retrograde axoplasmic transport and suggests that such transport may be greater in adults than in newborns.

Animals↗

Intestinal first-pass effects of estrone sulfate and estrone in the rat.

Mixtures of (14C)-estrone and (3H)-estrone-sulfate (10 micrograms and 13 micrograms, respectively) were instilled into the lumina of intact jejunal loops of rats. Estrone was faster absorbed into portal blood than was estrone-sulfate (72% vs. 17% in 30 min). In portal blood the chemical forms derived from estrone were: unchanged estrone (72%), estrone-glucuronide (14%), estrone-sulfate (5%) and estradiol (9%); no estriol was formed. The chemical forms of estrone sulfate were: estrone-sulfate (86%), estrone (6%), estrone-glucuronide (2%), estradiol (2%) and estradiol-sulfate (4%). These metabolites were also found in the lumen. It is concluded that the intestinal first-pass effects do not significantly influence the hormonal activities of the two estrogens.

Animals↗

Percutaneous pyelolithotomy. Case report and technical comments.

A case of nonoperative renal stone extraction through a nephrostomy tract is described. The stone was removed with the aid of a newly constructed device. The advantage of this device over a Dormia stone basket is that it has a steerable tip, which facilitates trapping of the stone in the basket.

Aged↗

The guidance of optic axons in the developing and adult mouse retina.

Previous studies in chick embryos (Goldberg, '77) indicated that unidirectional guidance of retinal axons toward the optic nerve is restricted to the vitread portion of the ganglion cell fiber layer (GCFL) of the retina; random fiber growth was noted after deflection of the optic axons sclerad to the GCFL. The present study on mice confirms these observations. Silver-stained flat mounts of retinal colobomas were examined. Many optic axons in colobomas do not exit normally from the eye, but travel randomly when deflected sclerad to the GCFL. Newborn mouse axons grew around retinal lesions in a highly directed manner. Such axons were always situated in the vitread portion of the GCFL. The unidirectional guidance found in newborn mice was absent in adults. Deflected adult axons traveled randomly regardless of their level within the GCFL. We propose that defective guidance largely accounts for failure of axonal regeneration in the adult mouse retina. The inability of the adult axons to fasciculate (adhere to one another and form fiber bundles) suggests that impaired cellular adhesivity may be part of the mechanism of regenerative failure.

Animals↗

Pyridine-silver methods for the study of optic axons in retinal whole mounts.

The optic fibers in the retinas of diverse species may be selectively stained and viewed en bloc in the embryonic and adult states. Treat the eye as follows: 1) 50% pyridine for at least 16 hr, 2) distilled water 3--4 hr, 3) 20% H2O2 until the eye is a light brown, 4) 95% ethanol overnight, 5) 1.5% AgNO3 for 2--6 days at 37 C, 6) in water, remove the vitreous, then direct 0.25% pyrogallic acid in 1.25% formalin against the retina for 2--5 secs until the optic fibers are reduced to a coffee-copper color (1--4 minutes), 7) dissect the retina and mount flat on a glass slide, 8) cover with glycerin, apply a coverslip, and fix in place with nail polish. Variants for particular species are given. The technique offers an advantage over Golgi and methylene blue methods which tend to stain only a small percentage of fibers and frequently do not work at the earliest stages of development.

Animals↗