Biomedical subjects
Publications and source records attributed to H Weinberg.
We have related the radiographic width of the psoas muscle to age, degree of osteoporosis, height, and weight, and to constitution in 234 subjects. The psoas width correlated well with age. When the subjects were grouped according to age, an association was observed between narrowing psoas width and increasing osteoporosis. Narrowing of the psoas was evident some years prior to radiographic evidence of osteoporosis.
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Polylysine induced rapid aggregation of large unilamellar vesicles composed of phosphatidylcholine-cardiolipin (1:1 molar ratio) but not their fusion. Application of the terbium-dipicolinic acid fusion assay showed that addition of polylysine at nanomolar concentrations enabled a significant lowering of the Ca2+ threshold concentration for vesicle fusion from 9 to 1 mM. Analysis of the kinetics of fusion with a mass-action kinetic model showed that polylysine enhanced significantly the rate of aggregation but affected only slightly the rate of fusion per se. Maximal enhancement of overall fusion rates occurred at a charge ratio (polylysine/cardiolipin) of about 0.5. At larger polylysine concentrations, e.g., at charge ratios greater than 3, polylysine inhibited vesicle fusion.
Prolonged ischemia may result in tissue death because of the no-reflow phenomenon. By raising a flap 24 hours prior to subjecting it to ischemia, the authors have been able to significantly lengthen the ischemia interval prior to the onset of tissue death. These effects are believed to be the result of alteration of the no-reflow phenomenon.
The dynamic process of skin flap neovascularization can be quantitated in a relatively non-invasive fashion in an "in-vivo" model using the technique of perfusion fluorometry. The extent of skin flap ischemia can be monitored, and its effect on angiogenesis rapidly determined. Evidence is presented that indicates that angiogenesis develops from a distal to proximal direction corresponding to the degree of ischemia as measured by fluorescein uptake and elimination. Furthermore, although certain proximal segments of skin flaps demonstrated no uptake or elimination, survival could still occur, indicating that neovascularization need not be complete at the time of pedicle interruption.
An imbalance of osteoblastic bone formation and osteoclastic bone resorption is thought to be responsible for the osteoporotic condition. The pathological events leading to this disorder are, in most instances, uncertain. A defect in the ability of osteoporotic patients to respond to foreign histocompatibility antigens in a mixed leukocyte reaction is reported here. The results further show that this defect is due both to a poorly responding lymphocyte population as well as to a suppressor factor in osteoporotic sera. In addition, there is a significant increase in the relative and absolute numbers of T cells in the patients' peripheral blood, while serum IgG, IgA, and IgM remain within the normal range. These findings are discussed in the light of a common immunopathological pathway regulating osteoclastic activity and leading to the osteoporotic condition.
The following case report presents a patient with transitional cell carcinoma of the bladder referred to this medical center after carcinomatous meningitis developed. Previously he had undergone surgical resection of the primary lesion and had received cis-platinum chemotherapy for lung metastasis. This unusual presentation of metastatic disease (carcinomatous meningitis) seems to alert the surgical and medical communities to new complications.
The authors have studied the effects of various circulatory settings on flap survival. The dog model was used to study the survival of venous flaps without arterial inflow both as island and free flaps. Venous flaps were compared with arterial flaps without venous outflow and standard island flaps with arterial inflow and venous outflow. Attempts were made to study their vascular morphology and blood gas changes. The venous flaps without arterial inflow survived with normal hair growth and wound healing, as did the standard island flaps. These observations suggest that capillary diffusion can occur without the continuous flow of blood through a capillary. Several possible mechanisms to explain survival of the venous flaps without arterial inflow were discussed. These observations could be important in providing an animal model to study microcirculation and a possible new area for microsurgical transfer of a skin flap.
Blood types of patients admitted to the Hadassah University Hospital with ankylosing spondylitis did not differ significantly from the expected percentages among the Israeli population, except for a very high incidence (92% to 100%) of homozygous MM. Among healthy controls the incidence of homozygous MM was found to be in line with accepted values.
A family of 114 people in six generations, of whom 45 were affected by multiple epiphysial dysplasia, was described in this Journal in May 1960. We have been able to review them again 23 years later, and also to report on the type and incidence of the disease in more children and in a further generation. The relative severity of the disease in different branches of the family has been unchanged through the generations. Patients who were previously hopelessly crippled can today be rehabilitated by total hip replacement. Genetic counselling and birth control have reduced the relative and absolute numbers of affected children; this is tending to make the disease self-limiting.
Fiberoptic perfusion fluorometry and assessment of ultimate viability were used to analyze the tolerance to warm ischemia of rat vascular island skin flaps. Both acute flaps and flaps raised 24 hours previously and then reraised were subjected to 0 (control), 6, 8, 10, and 12 hours of vascular pedicle clamping. Following clamp release, serial fluorometry documented the progressive delay in effective reflow resulting from extended periods of ischemia. Fluorometry, furthermore , suggested that flaps constructed 24 hours previously had an improved hemodynamic status with a significantly reduced period of poor reflow following clamp release. The improved hemodynamics were associated with increased viability, confirming the increased tolerance of 24-hour-old flaps to warm ischemia.
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It appears to be clear from the results that the third order gradiometer is able to detect small biomagnetic signals from the brain which are related to evoked potentials and spontaneous electrical activity. The instrument operates reasonably well within a noisy environment, however further development is necessary to balance the first gradient. We intend to pursue this direction with software systems. Some of the data presented suggest that components of MEG evoked activity may change independently of EEG. One interpretation which may derive from this is that the same current dipoles are probably not responsible for the entire configuration of evoked fields. This interpretation is consistent with EEG evidence which indicates that analogous components in the evoked potential may vary independently as a function of stimulus parameters and information processing. Perhaps a model of magnetic dipoles due to small current loops would be more compatible with the electrophysiological data.
CT scans of 18 hips with typical congenital dislocation have been studied in 16 children. These show that the common position of dislocation is lateral, superior and slightly anterior, and that a "false acetabulum" can be distinguished even in young children. A defect in the posterior ischium causing distortion of the acetabulum was also present in most cases. The cartilage and the acetabular contents were well shown. Positions of reduction and the anteversion of the acetabulum and the femoral neck were studied. Hypotheses are presented on the mode of dislocation and on the cause of the pathological changes.
Voluntary movements are preceded by a slow electrical potential of the brain (Bereitschafts-potential, BP) or readiness potential. The BP is accompanied by a magnetic field shift of similar time characteristics (Bereitschaftsmagnetfeld, BM). The BM preceding volitional right foot or toe movements was recorded from anterior, posterior, and lateral positions of the scalp using a SQUID (Superconducting Quantum Interference Device) third-order gradiometer. Controls were implemented to reduce head movements, which were simultaneously recorded with a mechanograph. The results showed that movements of the lower extremities are also preceded by a BM. However, contrary to finger movements, BMs with field lines directed into the head were found predominantly for foot movements and exclusively for toe movements. The BM preceding foot movements was maximum over a position 2 cm left of the vertex, i.e., contralateral to the movement. Two centimeters right of the vertex it was smaller, thus exhibiting a normal contralateral preponderance and not sharing the paradoxical side preponderance of the electrical BP preceding foot or toe movements. The BM preceding toe movements was only apparent at the vertex and was smaller than the one preceding foot movement. This may suggest a source that is located still deeper in the brain than with foot movements.