Biomedical subjects
Publications and source records attributed to S Weiner.
A technique for transitional restoration fabrication has been described. It permits modifications of existing axial and occlusal tooth contours to be accurately reproduced in transitional restorations.
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The pathogenesis and optimal treatment of choledochal cyst have long remained questions of considerable speculation and dispute. Because the pregnancy of a 37-year-old woman was felt to be at risk, five antenatal ultrasound examinations were made. The fourth examination at 31.5 weeks of gestation demonstrated a choledochal cyst. Following birth, the child was studied with repeat ultrasound examinations and scintigraphy. The results of these studies plus the findings at surgery contributed new evidence regarding the possible pathogenesis and optimal treatment of choledochal cysts. Although the time at which the cyst originated is compatible with the concept of reflux of pancreatic juice into the common duct, no abnormal junction of the pancreatic and common duct was identified. No evidence of obstruction as part of the pathogenesis could be demonstrated. Progressive changes in the choledochal cyst in the first ten days of life suggested that delay in diagnosis and treatment of a choledochal cyst may contribute to early complications such as cholangitis. Early excision of the cyst in the newborn is considered to be the optimal treatment and may pose less risk to the patient than delayed surgical exploration.
At the Bone Mineral Laboratory of the University of Wisconsin a microcomputer-based digital read-out system was designed specifically for determining bone mineral content (BMC) and bone width (BW) in newborn infants with the following features: (1) high accuracy and precision; (2) high reproducibility in vivo; (3) direct read-out of BMC and BW; (4) automatic data calibration; and (5) use of a low activity [125I] source (less than 50 mCi). BMC and BW were determined on the left radius on a series of 114 newborn infants of all gestational ages and a curve for intrauterine bone mineral content extrapolated from the data. Accuracy of the photon absorptiometric system was assessed by measuring BMC on a series of nine small bone sections (29-212 mg/cm) and confirmed by subsequent ashing of these bone sections (r = 0.99). Short-term precision (weekly, coefficient of variation 1.7%) and long-term precision (monthly, coefficient of variation 2.1%) for measuring BMC were determined by multiple determinations on a four-chambered bone phantom calibrated with the bone sections. Immediate reproducibility (without repositioning the arm) for the 4-6 scans performed for each determination of BMC and BW was good with a mean coefficient of variation of 3.9% for BMC and 3.6% for BW. In 84 infants, repositioning error was determined by repeating the measurement of BMC and BW after repositioning the arm. The correlation coefficients between measurements before and after repositioning the arm were 0.97 for BMC and 0.95 for BW. BMC correlated well with gestational age (r = 0.92), birth weight (r = 0.89) and bone width (r = 0.92). BW also correlated with gestational age (r = 0.84) and birth weight (r = 0.85). A multiple linear regression analysis of BMC versus BW, gestational age, and birth weight was done. The correlation coefficient between the predicted BMC from these variables and measured BMC was 0.95. Photon absorptiometry can be used with high accuracy, precision, and reproducibility in vivo in newborn infants. BMC correlates with gestational age, birth weight, and bone width.
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Biopsies of human periapical lesions obtained during endodontic surgery were studied morphologically and histochemically to determine the nature of the inflammatory reaction. Evaluation was based on cell types, morphologic patterns, degree of cellular infiltration, extracellular components, and their interrelationships. Almost all periapical lesions showed the characteristic features of granulomatous inflammation; chronic (nongranulomatous) inflammation was a lesser component of the reaction. Acute inflammation was seen either as focal concentrations or as scattering of polymorphonuclear neutrophilic leukocytes in variable numbers throughout the chronic and granulomatous inflammatory tissue. Epithelium was noted in one third of the specimens. Granulation tissue was not seen. Thus, granulomatous inflammation appears to be a consistent inflammatory reaction pattern in periapical lesions.
An attempt was made to characterize the nature of the functional organization of the hypothalamus by observing the patterns of uptake of 14C-2-deoxyglucose (2DG) following electrical stimulation of different regions within the preoptico-hypothalamus in the rat. The experimental paradigm consisted of electrical brain stimulation delivered continuously for periods of 30 sec on and 30 sec off for 45 minutes following injection of 2DG. Brains were removed and processed for autoradiography. Activation of the medial forebrain bundle was noted following stimulation of the nucleus accumbens and lateral preoptico-hypothalamus. Activated fibers could be followed only in a caudal direction through the medial forebrain bundle and into the ventral tegmental area as a result of nucleus accumbens stimulation. Stimulation of the lateral preoptic region or of the anterior half of lateral hypothalamus produced activation of the lateral septal nucleus, lateral habenular nucleus, perifornical region, midline thalamus and ventral tegmental area. Since stimulation of the perifornical hypothalamus significantly activated the rostro-caudal extent of the midbrain cental gray, it is suggested that impulses from the lateral hypothalamus reach the lower brainstem via its connections with the perifornical hypothalamus. Ventromedial hypothalamic stimulation activated only the lateral septal nucleus, cortico-medial amygdala and medial preoptico-hypothalamus, while medial preoptico-hypothalamic stimulation resulted in increased 2DG uptake in the midbrain central gray, thus suggesting that medial hypothalamic impulses reach the brainstem by first ascending to the level of the preoptico-hypothalamus. Mammillary body stimulation orthodromically activated fibers in the mammillothalamic and mammillotegmental tracts and antidromically fibers in the fornix for a short distance.
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A twelve year old boy presented with sudden onset of severe hypertension and oligo-anuria. A diagnosis of Takayasu's Arteritis was made by aortography which demonstrated irregular narrowing of the lumbar aorta and renal arteries. Severe renal insufficiency necessitated maintenance hemodialysis. Hyperreninemic hypertension was intractable despite aggressive dialysis and multiple drug therapy. Renal biopsy after eight months of dialysis showed preservation of glomerular architecture. After nine months GFR improved spontaneously to 32 ml/min/1.73 m2 despite no improvement in his hypertension. This case report emphasizes the remarkable ability of renal parenchyma to recover function after sustained ischemia.
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