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Biomedical subjects

S Weinstein

Publications and source records attributed to S Weinstein.

At least 109 records · Page 6Linked to original sources
PubMed1984

Biclonal IgA and IgM gammopathy in lymphocytic lymphoma.

We report the case of a 76-year-old white man with a diffuse, well-differentiated lymphocytic lymphoma at the base of his tongue. Although serum electrophoresis, immunoelectrophoresis, and immunofixation showed he had a biclonal IgA kappa and IgM kappa gammopathy, biopsy of the tumor showed a positive immunoperoxidase response only for IgM kappa. The biclonal pattern persisted after chemotherapy, despite shrinkage of the tumor mass. The association of IgA and IgM appears to be the least frequent combination of separate biclonal immunoglobulins, the clinical course of such patients being more often that of lymphoma or macroglobulinemia than of myeloma. However, the symptomatology can be highly variable, as our case uniquely demonstrates.

Aged↗
PubMed1983

Sleep respiratory instability in term neonates under hyperthermic conditions: age, sex, type of feeding, and rapid eye movements.

The purpose of this study was to examine the influence of neonatal age, sex, type of feeding, and rapid eye movements on the occurrence of apneic pauses during sleep in a hyperthermic environment. One hundred and twenty fullterm infants (equally divided by sex and type of feeding) were observed during a complete nap within the first and approximately fourth wk of life. Each sleep session was characterized by twenty-one measures including the longest apneic pause, mean apnea duration, relative frequency of apnea, apnea periodicity, respiratory rate, and relative frequency of REM epochs. The relative frequency of REM epochs decreased with age and was greater in formula-fed (versus breast-fed) infants. The longest apneic pauses were greater in the first wk of life and in breast-fed infants. In addition, the average Longest Duration:REM was greater than the average Longest Duration:NREM. Of potential importance was the demonstration that this latter effect was greater in the first wk than in the fourth wk of life. Breast-fed infants and females had larger apnea Mean Duration scores. The relative frequency of apneic pauses (greater than or equal to 2 sec in duration), periodicity, and the relative amount of apnea were greater in the fourth-wk study and in breast-fed infants. The relative frequency of apneic pauses greater than or equal to 6 sec in duration (Apnea6%) and the A6/D% measure were greater in breast-fed infants. Numerous interactions were observed between age, sex, and type of feeding. Respiratory rate decreased with age and was greater during NREM epochs and in formula-fed infants.

Age Factors↗
PubMed1983

Stature, head height, and growth of the vertical face.

Six hundred sixty-three cephalometric radiographs are used in a mixed longitudinal sample of fifty-one subjects (twenty-six males and twenty-five females) in order to determine patterns of vertical facial change during growth and to discern lower, mid-, and upper facial relationships with stature and head height. Results indicate that the absolute growth of the face is similar to the neural pattern and that throughout growth the face is larger among males than among females. However, when facial values are examined relative to stature and head height, the vertical face changes at a rate that resembles statural growth. Moreover, when relative growth values are standardized in order to reduce scaling differences, they indicate that, although relative growth for all three facial measures falls between neural and skeletal values, it is closer to the postcranial pattern of change than to the neural pattern. In addition, relative size of the upper face is highly correlated with relative size of the lower face. It is concluded that stature is of greater importance than head height in the prediction of vertical facial growth.

Adolescent↗
PubMed1982

Physical properties of human lips: experimental and theoretical analysis.

The lip stiffness characteristics in the vertical plane of a white population sample, aged 18-26, were studied. The physical properties of the lip system were analyzed and a mathematical model was derived to approximate this system. The instrumentation consisted of a force-transducer bar, a head holder and a three-directional micrometer adjustment. Four specific contact areas were used. Individual lower lip is stiffer than upper lip and the corresponding male lip is stiffer than the female lip. The force-displacement relationship approximates a linear function at small displacements (less than 1 mm) and is a second order function at larger displacements. A mechanical T-spring model approximates the system to an accuracy of about 96%.

Adult↗
PubMed1982

Lip morphology and area changes associated with surgical correction of mandibular prognathism.

Changes in lip morphology and area, measured in two dimensions from standardized lateral head films, were assessed in a series of twenty adults at three times: pre-surgically, 8--14 months post-surgically, and a long-term follow-up at 5--7 years. All individuals received the same, single surgical procedure (Obwegeser sagittal split for correcting mandibular prognathism. Upper and lower lip changes were quantified as millimetres displacement of the lip centroid vertically and horizontally, plus changes in cross-sectional area. Direction and amount of change, its dependency on the amount and kind of surgically induced symphyseal changes, and the intercorrelations among lips and among lip and symphysis variables were statistically evaluated, both univariately and multivariately. Three measures are made of symphysis change: horizontal and vertical repositioning and amount and direction of rotation. Horizontal repositioning primarily affected the lengthening and areal increase of the upper lip. Vertical repositioning had its major influence in the height and cross-sectional area of the lower lip: a superior shift of the mandible made the lower lip shorter, more protrusive and smaller in area; an inferior shift produced an increase in lower lip height with increased area. The third variable, symphyseal rotation, had its greatest influence on the labial-lingual shift of the upper lip's centroid. The long-term follow-up showed little change from the 1 year post-operative conditions; equilibrium of the soft tissue components was then achieved fairly soon after surgery.

Adult↗
PubMed1982

Soft tissue fibrosarcoma. A case report and review of the literature.

The soft tissue fibrosarcoma usually presents as an enlarging, painless mass. Pain is usually a result of pressure on surrounding structures. Fibrosarcomas arise from connective tissue and demonstrate no calcification on x-ray studies. These expansile tumors are firm, round or lobulated, and well encapsulated. Their level of malignancy is graded on the basis of various degrees of differentiation of the anaplastic spindle-cells of which they are composed. Treatment generally consists of wide excision or radical local resection. Five-year survival estimates vary from 60 to 90 percent. The lung is the usual site of metastasis. A case of subungual fibrosarcoma of the great toe is presented.

Aged↗
PubMed1981

The high prevalence of impaired glucose tolerance and diabetes mellitus in an isolated Polynesian population, Manihiki, Cook Islands.

An epidemiologic survey of 133 adult Polynesians of Manihiki Atoll, Cook Island group, revealed a high prevalence of diabetes mellitus (males 8.0 percent, females 10.3 percent) and impaired glucose tolerance (males 8.0 percent, females 31.0 percent). Those with abnormal glucose tolerance were older, more obese, and engaged in less physical activity than normals. The females had a higher prevalence of both diabetes and impaired glucose tolerance than the males. Although Manihiki is geographically isolated, the islanders have a good income from copra and pearl shell. The change from a traditional to a modern way of life in a population with an increase susceptibility to diabetes is the probable cause of the high prevalence of abnormal glucose tolerance. The change in living patterns is a consequence of change from a subsistence existence to involvement in the cash economy.

Adult↗
PubMed1981

Use of fluorescent probes that form intramolecular excimers to monitor structural changes in model and biological membranes.

1,3-dipyrenylpropane (PC3P) and bis(4-biphenylmethyl)ether, two molecules that form intramolecular excimers, were embedded in phospholipid vesicles and biological membranes to monitor dynamic properties of membrane lipids. Excimer formation was evaluated from determinations of excimer to monomer emission intensity ratios (ID/IM). ID/IM values of PC3P and bis(4-biphenylmethyl)ether were reduced when cholesterol was added to egg lecithin vesicles. PC3P was sensitive to the temperature-induced crystalline to liquid-crystalline phase transition in dimyristoyl phosphatidylcholine vesicles. For studies of cellular membranes, membranes, PC3P was used exclusively, because of the fluorescence of tryptophan residues of membrane proteins interferes with the responses bis(4-biphenylmethyl)ether. Microviscosities of membrane interiors were calculated from standard curves of IM/ID plotted against solvent viscosity. Microviscosity values of egg lecithin vesicles and biological membranes, especially those obtained with PC3P, were more than an order of magnitude lower than values obtained by other techniques. We concluded that the intramolecular process leading to the formation of the excimer is influenced differently in isotropic solvents than in anisotropic environments, such as lipid bilayers. Although distinguishable ID/IM ratios can be obtained for different biological membranes (mitochondrial, microsomal, and plasma membranes were studied), this parameter may be phenomenological and not simply related to membrane microviscosity. As such, fluorescent probes that form intramolecular excimers are of value in making qualitative comparisons of different membranes and in studying the relative effects of physical changes and chemical agents on membrane structure. These probes may also be valuable for studying structural anisotropy of biological membranes.

Animals↗
PubMed1981

Bilateral buccolingual forces produced by extraoral traction.

Extraoral appliances have been typically employed to deliver force systems to move teeth in directions parallel to the sagittal plane of the face. Their potential for concurrently producing transverse (buccal or lingual) movement has still not been fully explored. This study considers theoretical and experimental aspects of the magnitude and direction of such forces and related moments.

Biomechanical Phenomena↗