[Influence of different construction procedures on occlusal accuracy of complete dentures].
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Dental Occlusion↗
Biomedical subjects
M Weiss
Publications and source records attributed to M Weiss.
Use of an adaptive noise canceler as an input preprocessor for a hearing aid.
The use of a two-channel adaptive noise canceler as a preprocessor for a hearing aid was evaluated. An omnidirectional microphone and a directional microphone were used as the inputs to the primary and reference channels, respectively, of the adaptive noise canceler. The microphones were mounted just above one ear on the head of a KEMAR mannikin. The system was found to work well under anechoic conditions, but showed only modest improvements in a moderately reverberant room (reverberation time 380 ms).
Acoustics↗
In vivo nuclear magnetic resonance spin-lattice relaxation time measurements from restricted volumes.
A method is described for performing localized in vivo spin-lattice relaxation time (T1) measurements in which data is taken along a strip or line. This method, which is used in conjunction with standard imaging practice, provides smaller T1 measurement times if only a limited number of measurements are required. Studies of the reproducibility and the homogeneity of these T1 determinations have been carried out using human subjects and phantoms. T1 measurements made of several regions of normal brain, abdominal, and pelvic organs are described.
Adult↗
Physical work capacity in chronic renal disease.
We studied the physical fitness of 71 patients with renal disease before dialysis, after starting dialysis, and after successful renal transplantation. Maximal muscle strength was determined in 58 patients and maximal cardiovascular capacity was assessed in 36 patients. Before dialysis there was a 31 percent reduction in muscle strength in men and 47 percent in women. The loss of muscle strength was most pronounced in the leg extensors. Cardiovascular capacity and muscle strength was positively correlated in the dialysis patients (p less than or equal to 0.05). The cardiovascular capacity was decreased 29% in predialysis patients, 45% in dialysis patients and 37% in transplanted patients compared to untrained healthy controls. The predialysis patients had a 19% greater cardiovascular capacity than the dialysis patients and a 9% greater cardiovascular capacity than the transplanted patients. While hemoglobin concentrations showed a positive correlation (p less than or equal to 0.05) with maximal cardiovascular capacity and creatinine concentration showed a negative correlation (p less than or equal to 0.05) with maximal cardiovascular capacity in the predialysis patients, hemoglobin concentrations and creatinine concentrations did not correlate with cardiovascular capacity in the dialysed and transplanted patients. In dialysis patients as well as in patients after kidney transplantation hemoglobin and creatinine concentrations, muscle strength, height, weight, and age are factors influencing the physical work capacity, but none of these variables alone seems to be a strong determination factor. Besides the complications of kidney disease which may itself reduce physical fitness, the lack of physical training is an important factor in determining the residual muscle strength and cardiovascular capacity for all patients with renal insufficiency.
Adult↗
Consequences of "conservative" conventional management of axillary vein thrombosis.
To evaluate the long-term effects of "conservative" management (heparin initially then Coumadin for 3 months) on patients with axillary vein thrombosis, the authors studied 20 patients (average age 44 years) who presented at the Wellesley Hospital in Toronto between 1975 and 1984. The diagnosis of axillary vein thrombosis was made from history, findings on physical examination and Doppler studies. In 12 patients, the diagnosis was confirmed by venography. Three patients subsequently underwent a first-rib resection for thoracic outlet syndrome. The average follow-up was 42 months. The cause of the thrombosis in 3 patients was an intravenous-line catheter, in 7 it was effort thrombosis and in 10 the cause was unknown. Two patients had had a previous deep venous thrombosis in the lower limb. Results of conservative treatment showed that only five patients had residual minimal swelling and two had minor discomfort. These symptoms did not interfere with either leisure or work activities in any of the patients. Fifteen patients were asymptomatic. One patient had nonfatal pulmonary embolism. The conservative management of axillary vein thrombosis is safe, effective, relatively inexpensive and gives excellent long-term results. The prognosis is good, irrespective of the cause of the thrombosis and, in view of this, a more aggressive approach, using either streptokinase therapy or thrombectomy, does not appear to be justified.
Adult↗
Safety of cholecystectomy with abdominal aortic surgery.
Many surgeons are reluctant to remove asymptomatic gallstones during aortic reconstruction for fear of increasing the risk of graft infection. This is a review of 56 patients who underwent aortofemoral bypass or aortic aneurysm repair, with cholecystectomy, to determine if the morbidity or mortality was increased with the concomitant procedure. Follow-up averaged 25 months (range from 1 to 125 months). Three patients were lost to follow-up. Operative and postoperative hospital stay were not increased. One patient suffered a graft infection and a pseudoaneurysm; the infection was not related to the cholecystectomy since it occurred after a secondary procedure for repair of an infected false aneurysm. There were three superficial infections and three postoperative deaths, none of which specifically related to the cholecystectomy. The only related complications were three bile leaks, one liver injury due to a retractor and bleeding from the gallbladder bed in one patient who required reoperation. The authors conclude that concomitant cholecystectomy can be performed without increased risk to the patient but is advised only if the vascular procedure has been uncomplicated and the cholecystectomy appears straightforward.
Aorta↗
Psychosocial correlates of blood pressure in childhood and adolescence. First stage of a prospective study.
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Achievement↗
Care and support of women who have experienced a stillbirth.
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Female↗
[Electrolyte volume homeostasis, the sympathetic nervous system and circulatory reactions in swimmers. Comparison of highly-trained and untrained swimmers].
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Adolescent↗
[Primary dissection of the left coronary artery with rupture of the ventricle in a 27-year-old patient].
This report of a 27-year-old patient describes an extensive infarction of the anterior wall due to primary dissection of the left coronary artery in the absence of the circumflex artery followed by rupture of the left ventricle. In earlier reports an aortocoronary bypass operation was usually performed in similar situations. Although the final outcome was lethal, this case report shows recanalization by methods of "interventional cardiology" to be a potentially successful alternative which may be of value when bypass operation is not available or contraindicated, as in developing cardiogenic shock. This case report demonstrates an initially successful treatment, which after a stable interval was followed by a lethal complication, namely, rupture of the ventricle due to hemorrhagic infarction.
Adult↗
Determination of "in vitro" degradation of protamine in plasma by three different methods.
Three techniques for the quantitative or semi-quantitative determination of the degradation of protamine in plasma are described. One is based on the measurement of liberated arginine, since arginine is the single most important constituent of protamine (80% in weight). The second utilizes successive estimations of protamine by addition to a secondary heparinized medium in which excess heparin is measured by thrombin time and polybrene titration. The third method employs electrophoresis on cellulose acetate, and offers direct visualization of the soluble complexes formed between protamine and albumin, and of their degradation. When applied to an incubation mixture containing diluted plasma (1 : 8) and protamine 0.8 mg/ml, the first two methods were well correlated and showed that protamine degradation proceeded linearly with time. The third method had good semiquantitative agreement with the two former. The rate of protamine degradation was different when estimated by each of the three methods, due probably to the different physico-chemical reactions involved.
Arginine↗
Demonstration of the association of the cell-surface enzyme, 5'-nucleotidase, with microvillar microfilaments by phalloidin shift on velocity sedimentation gradients.
The cell-surface enzyme 5'-nucleotidase in microvilli from 13762 rat mammary adenocarcinoma cells remains largely associated with microfilament-containing high-speed pellets from Triton X-100 extracts of the microvilli. The fraction remaining with the insoluble portion is higher under ionic conditions which enhance microfilament stability. To minimize trapping and cosedimentation we have analyzed the distribution of microfilaments and 5'-nucleotidase activity on velocity sedimentation sucrose gradients of the microvillar extracts. A large fraction of the total enzyme activity is found in the filament fractions in the middle of the gradient. When phalloidin is included in the extraction buffer to stabilize the microfilaments, both the microfilaments and the bulk of the nucleotidase activity are shifted further into the gradients. Both the position of the filament fraction and the percentage of the total nucleotidase activity remaining with the filament fraction varies with extraction buffer composition and conditions. Nonetheless, under all conditions tested, a large percentage of the activity was shifted, along with the microfilaments, in the presence of phalloidin. These results are consistent with a specific association of 5'-nucleotidase with microfilaments in the ascites tumor cell microvilli.
5'-Nucleotidase↗
Pharmacokinetics of isosorbide-5-nitrate in renal failure.
The pharmacokinetics of the antianginal drug isosorbide-5-nitrate (IS-5-N) was studied in 20 patients with varying degrees of chronic renal failure after repeated oral doses of standard 20 mg tablets t.d.s. Blood samples were taken in the steady state on the 2nd and 28th days, and the plasma level was assayed by HPLC. There was no statistically significant difference in Cssmax, t1/2 and AUCss0-8 between the 2nd and 28th days, nor was a difference found between patients with mild and severe renal failure.
Aged↗
Generalizations in linear pharmacokinetics using properties of certain classes of residence time distributions. I. Log-convex drug disposition curves.
Introducing the phenomenological concept of a time-varying fractional rate of elimination kD(t) and applying the theory of lifetime distributions, implications of the log-convexity of drug disposition curves are examined and some important applications are described. Linear pharmacokinetic systems exhibiting a log-convex impulse response and satisfying the basic conditions underlying the noncompartmental approach have the following properties: (1) The time-varying volume of distribution V(t) increases, and consequently the fractional rate of elimination kD(t) = CL/V(t) decreases monotonically. (2) The concentration-time curve and the time course of total amount of drug in the body, respectively, have an exponential tail [where V(t) approaches the equilibrium value VZ]. The relative dispersion of residence times (CV2D = VDRT/MDRT2) and the ratio Vss/VZ (Vss is the volume of distribution at steady state) act as measures of departure from pure monoexponential decay (one-compartment behaviour). The role of the latter parameters as shape parameters of the curve that characterize the distributional properties of drugs is discussed. Upper and lower bounds of the time course of drug amount in the body are derived using the parameters MDRT and CV2D or lambda Z (terminal exponential coefficient), respectively. This approach is also employed to construct upper bounds on the fractional error in AUC determination by numerical integration that is due to curve truncation. The significance of the fractional elimination rate concept as a unifying approach in interspecies pharmacokinetic scaling is pointed out. Some applications of the results are demonstrated, using digoxin data from the literature.
Animals↗
Beneficial effects of polyunsaturated fatty acids in partially nephrectomized rats.
Evening primrose oil, safflower oil, and salmon oil, all with high polyunsaturated fatty acid content, were fed to partially nephrectomized rats; the effects were compared to those of feeding beef tallow. All three oils had favorable effects on progression of renal failure, salmon oil on kidney histology as well. The changes induced in platelet production of thromboxane A2, and in the renal production of various eicosanoids may explain the protective role of these oils.
Animals↗
Protective effect of polyunsaturated fatty acid supplementation in apoferritin induced murine glomerulonephritis.
The effects of increasing two dietary polyunsaturated fatty acids, eicosapentaenoic and linoleic, on the glomerulonephritis induced by repeated injections of apoferritin in the mouse were studied. Urinary protein excretion was measured serially; serum creatinine, aortic and renal production of eicosanoids and kidney histology were measured at sacrifice at 8 weeks. Both high EPA and LA feedings were associated with lesser proteinuria, normalization of renal function and profound changes in the tissue production of prostaglandin and thromboxane, which may explain their protective effect in this model of renal disease.
Animals↗
Differences in steroid metabolism by testis, prostate and epididymis in the immature and adult possum (Trichosurus vulpecula).
Immature possums 126-195 days old and adults over 1 year old were used. Testicular homogenates from immature possums converted [3H]progesterone to nine different products, of which greater than 63% were 5 alpha-reduced androstane metabolites. The major product from adult testis was testosterone in yields greater than 60%. While metabolism of [3H]testosterone by the epididymis of immature possum was minimal, in adults 5 alpha-reduced products constituted greater than 80% of the yield. In contrast, prostatic tissue from adults converted less than 4% of [3H]testosterone to 5 alpha-reduced products, while the yields were greater than 80% from prostates of immature animals. The results showed that like in rodents, the testis of immature possum has a high 5 alpha-reductase and low 17 beta-hydroxysteroid dehydrogenase activity, which reverses in the adult state. The implications of the findings are discussed.
Androgens↗
Resistance of Berne virus to physical and chemical treatment.
Thermal inactivation of Berne virus proceeded at a linear rate between 31 degrees and 43 degrees C. Storage at temperatures lower than -20 degrees C preserved the infectivity, while at 4 degrees C appreciable loss occurred between 92 and 185 days. Freeze-drying or desiccation at 22 degrees C caused only insignificant loss of infectivity. Virus preparations were not affected by pH values between 2.5 and 10.3. Inactivation by UV occurred more rapidly than with herpes, toga and rhabdoviruses. Berne virus infectivity was sensitive to pronase and B. subtilis proteinase. It was not inactivated by trypsin and chymotrypsin treatment, which resulted in enhancement of infectivity; low concentrations of pronase (less than 10 micrograms ml-1) had a similar effect on Berne virus. Neither phospholipase C or RNase, alone or in combination, nor sodium deoxycholate (0.1%) inactivated the virus; in contrast, Triton X-100 (0.1%; 1.0%) caused rapid inactivation with a constant level of residual infectivity.
Animals↗