A standardized interviewing technique for evaluating postgraduate training applicants

In an effort to streamline the personal interview and to reduce the influence of subjectivity inpreparation of ranking lists for postgraduate year-one applicants, a standardized interview was constructed for use in evaluating condidates for admission to a training program in internal medicine. The interview was conducted in a uniformly structured manner by 14 interviewers of 260 applicants. Each applicant received an interview score which correlated well with the final decision of the Intern Selection Committee. For each interviewer various measures of performance were obtained which allowed a classification into "hard" versus "easy" interviewer and indicated the comparability of each interview's evaluations with the final decisions. Thus, the standardized interview resulted in quantifiable data in the form of uniform evaluations of applicants and interviewers.     

Surgical significance of extrahepatic biliary tree anomalies

A patient with an anomalous insertion of the right hepatic duct into the cystic duct was noted during cholecystectomy and confirmed by operative cholangiography. This case and related anomalies of the bile ducts are of sufficient importance that, because of the technical difficulties and dangers incidental to their presence, no surgeon who operates on the gallbladder and bile ducts can afford to be unaware of their existence. Adequate exposure, careful dissection, and accurate knowledge of the regional anatomy plus a realization of the frequency and multiplicity of abnormalities of the extrahepatic biliary tree are requisites for safe biliary tract surgery. In addition, carefully performed operative cholangiography can be an indispensable aid in the clarification of anatomic variations. In case of recognized operative injury to the extrahepatic biliary tree, primary repair or biliary-intestinal anastomosis can usually be carried out with good results.     

Genetic regulation of storaage protein content in maize endosperm

Sodium dodecylsulfate-polyacrylamide gel electrophoresis reveals that zein prepared from normal maize inbred (Zea mays L.) contains six separable components. Z1 and Z2 are the predominant species, with molecular weights of 21,800 and 19,000 daltons. Amino acid analysis of these two components shows that both are rich in glutamic acid, leucine, and proline, but low in lysine. Of the four minor bands, Z3, Z4, Z5, and Z6, the latter two exist only in trace amounts. A mutation at the opaque-2 locus severely suppresses the synthesis of Z1. The nonallelic mutant, opaque-7, strongly suppresses the synthesis of Z3 and Z4, while slightly reducing Z2. On the other hand, the floury-2 mutant appears to reduce the synthesis of these six proteins in the same relative proportion. In the double mutant combinations, opaque-2 apparently is epistatic to opaque-7 and floury-2 in the synthesis of zein components. The glutelin fraction shows a more complex banding pattern; however, qualitative differences are not apparent among the mutant lines examined.     

Pantothenic acid, coenzyme A, and human chronic ulcerative and granulomatous colitis

To investigate further an apparent relationship between chronic ulcerative and granulomatous colitis and pantothenic acid deficiency, colonic tissues obtained at the time of colectomy in 29 patients with these disorders were assayed for pantothenic acid and for coenzyme A (CoA) activity. For comparison, normal colonic tissues free of pathological lesions were obtained from 31 patients having colectomy for carcinoma or diverticulitis. Plasma, red blood cells, and colonic mucosa were assayed microbiologically for free and total pantothenic acid. The activity of CoA in colonic mucosa was determined by assaying the acetylation of sulfanilamide. Concentrations of free, bound, and total pantothenic acid in blood and in colonic mucosa did not differ between the two groups of patients. Bound pantothenic acid increased linearly with total pantothenic acid. Colonic mucosa concentrated free pantothenic acid to about 50 times the level of blood, and pantothenic acid in red cells was similar to the concentration in plasma. Compared to normal gut mucosa, CoA activity was markedly low in mucosa from patients with chronic ulcerative or granulomatous disease despite the presence of normal amounts of free and bound pantothenic acid. A block in the conversion of bound pantothenic acid to CoA in diseased mucosa is suggested.     

Membrane microviscosity and human platelet function

An increased sensitivity to epinephrine-induced aggregation has been observed both in platelets obtained from patients with type IIa hyperlipoproteinemia and in normal platelets following incubation with cholesterol-rich lecithin dispersions. We have reported previously that the membrane fraction of platelets is enriched with cholesterol relative to phospholipid under each of these conditions. To further explore the effect of cholesterol on platelet membranes, we have examined the fluidity (microviscosity) of whole platelets and platelet subcellular fractions using a hydrophobic fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), under conditions in which the cholesterol-to-phospholipid mole ratio (C/PL) of platelets was varied by incubation with various cholesterol-lecithin sonicated dispersions. The C/PL of platelets directly influenced the rotational diffusion of DPH, as indicated by changes in fluorescence polarization. This was reflected in an increase in microviscosity at 37 degrees C (ETA37) from 2.84 P in normal platelets to 4.06 P in platelets with a 118% increase in C/PL. Conversely, platelets with a 43% decrease in C/PL had a 13% decrease in eta37. A strong correlation (r = 0.94) existed between C/PL and eta37 throughout this entire range. However, C/PL had no effect on the excited-state fluorescence lifetime of DPH. Both C/PL and eta37 were lower in isolated platelet membranes than in the platelet granule fraction. When platelets were incubated for 20 h with cholesterol-rich dispersions, there was an increase in C/PL and eta37 in both the membrane and granule fractions. However, this occurred more rapidly in membranes so that, at 5 h (a time when an increased sensitivity of whole platelets to epinephrine is evident), membrane C/PL had increased 55% and eta37 had increased 42%, whereas granule C/PL and eta37 had changed minimally. Cholesterol-rich platelets and subcellular fractions had a lower fusion (or flow) activation energy for viscosity (deltaE), reflecting a higher degree of order, and the converse was true in cholesterol-poor platelets. Moreover, a strong negative correlation existed between the percent change in deltaE and the percent change in eta37 induced either by cholesterol incorporation or depletion. These data demonstrate that cholesterol influences the fluidity and the degree of order within the hydrophobic core of platelet membranes. Changes induced in these physical properties by an excess of cholesterol relative to phospholipid may underlie the abnormal reception or transmission of the aggregation stimulus in cholesterol-rich platelets.     

Effects of continuous light and darkness on the eyes of the troglobitic salamander Typhlotriton spelaeus

Larval Typhlotriton spelaeus collected from five caves in Pulaski Co., Missouri, were kept as larvae or induced to transform in darkness or continuous fluorescent illumination. Larvae maintained in darkness for 215 and 279 days had smaller eyes, smaller rod inner and outer segments, and fewer metaphase figures in the germinative zone of the neural retina than comparable larvae maintained in light (258 lux). Except for visual cell size, differences were small and for each characteristic exceptions were observed. One larva kept in light showed early retinal degeneration comparable to that in transformed adults to T. spelaeus. All larvae exhibited optomotor behavior both before and after the experiment. Among animals induced to transform by L-thyroxin and maintained in darkness 111 to 366 days, visual cell and pigment epithelium degeneration was more extensive and more frequent than in animals kept for the same length of time in light (237-298 lux). In darkness the frequency of animals with retinal degeneration increased between 111 and 366 days. In light some animals exhibited pigment epithelium reduction with normal visual cells, and others had free, pigmented cells in the subretinal space. These effects were not comparable to degeneration in darkness. Eyelids covered the eyes of only a few animals in both light and dark treatments. The extent of eyelid encroachment over the eye greater in darkness than in light. Most animals exhibited optomotor responses after experiments, but responses of animals kept in darkness were impaired in comparison to those of animals kept in light.     

Dacryoscintigraph evaluation of the repaired lacrimal drainage system

We have used dacryoscintigraphy to study the efficiency of the lacrimal system following the repair of a divided lower canaliculus in 4 children. This test has been reliable in evaluating lacrimal function and suggests that a canaliculus can be repaired and splinted satisfactorily. Our experience with dacryoscintigraphy confirms that it is a safe comfortable, and reliable method for studying the patency of the lacrimal drainage system.     

The renal medulla and mechanisms of hypertension in the spontaneously hypertensive rat

A significant number of offspring from brother-sister matings of NIH-Okamoto-Aoki spontaneously hypertensive rats (SHRs) were found to be normotensive at 20 weeks of age. Over 20% of the animals that were hypertensive at this age had mild-to-moderate unilateral hydronephrosis at the time of sacrifice. In over 90% of the rats that did not develop hypertension spontaneously, ligation of one ureter raised blood pressure above 150 mm Hg within 2 weeks. In those rats made hypertensive by obstructing one ureter and in those that developed hypertension with accompanying naturally occurring hydronephrosis, subcutaneous implants of fragmented renal medulla from unrelated normal rats decreased blood pressure to normotensive levels. In contrast, medullary implants had no significant effect in rats developing hypertension spontaneously without hydronephrosis. Renal inner medullary plasma flow was low in the obstructed kidneys of hydronephrotic hypertensive SHRs but was elevated in the kidneys of nonhydronephrotic hypertensive SHRs. The hypertension in hydronephrotic SHRs appears to be related to an impairment of the antihypertensive function of the renal medulla. Such an impairment of medullary antihypertensive function does not appear to play a significant role in the hypertension in SHRs without hydronephrosis.