Biomedical subjects

P Shapiro

Publications and source records attributed to P Shapiro.

At least 19 recordsLinked to original sources

PubMed1995

Biomechanical and clinical evaluation of the epitenon-first technique of flexor tendon repair.

Thirteen matched pairs of canine flexor tendons were repaired using both the Epitenon-first and the modified Kessler with an epitendinous running suture. These were then tested to failure with a longitudinal force in an Instron test machine. Human cadaver flexor digitorum profundus tendons were used to determine the cross sectional area of the tendon that is displaced by suture material of the Kessler repair and Epitenon-first core suture. Results of biomechanical testing revealed the epitenon-first technique to be 22% stronger than the modified Kessler technique. Comparison of tendon repair cross sectional contact areas by digital scanning of surface photomicrographs demonstrated 20% of the surface area of the repair is occupied by the knot of the modified Kessler technique, while the core suture of the epitenon-first repair consumed only 2.6% of the cross sectional area. These findings correlate with our clinical results of 26 zone II flexor tendon repairs in 18 patients repaired with the epitenon-first technique over a 4-year period. Of these, there has been one rupture and no repeat operations for lysis of adhesions.

Adolescent↗

PubMed1995

Temporal variation in nasal and oral breathing in children.

The purpose of this study was to measure several variables associated with respiratory function at repeated intervals. The temporal variation of these variables was assessed within persons and within the sample population. Twenty-nine children, 18 boys and 11 girls, between the ages of 7 and 13 years of age, participated. Each subject attended three separate appointments. At each appointment, the percentage nasal breathing was measured three times with inductive plethysmography. The nasal resistance and smallest nasal cross-sectional area were measured once at each appointment with posterior rhinomanometry. The findings suggest a significant amount of variation in repeated measurements of respiratory variables. More variation was noted in measurements taken on different days than within 1 day. No correlation was present between either nasal resistance or nasal cross-sectional area in relation to percentage of nasal breathing. All subjects had a nasal component of respiration; no one was a 100% oral breather. No correlation was observed between age or gender of the subjects and any of the respiratory variables measured.

Adolescent↗

PubMed1994

Hyperoxia inhibits proliferation of cultured rat tracheal smooth muscle cells.

Exposure of the lung to elevated oxygen leads to structural and cellular injury followed by extensive tissue remodeling. In vitro models utilizing isolated cells exposed to hyperoxic conditions or exogenously added oxidants may be injurious or stimulatory depending on the specific cell type and level and duration of exposure. In the present study, proliferation of cultured rat tracheal smooth muscle cells was inhibited by oxygen concentrations of 40 and 70% compared with a "normoxic" concentration of 21%. Exposure to 70% oxygen had a hypertrophic effect on the cells, as indicated by increased cellular protein content, whereas cells exposed to 21% oxygen did not show increased protein content. Exogenously added oxidant, H2O2, resulted in complete inhibition of growth of tracheal smooth muscle cells at concentrations > 3 microM. Much higher concentrations of H2O2 were required to inhibit proliferation of vascular smooth muscle cells and rat lung fibroblasts. The heightened sensitivity of airway smooth muscle cells to oxygen and oxidants may be an important factor in the early events following hyperoxia-induced lung injury.

Animals↗

PubMed1994

Energy deposition and ionization fluctuations induced by ions in small sites--an analytical approach.

A concise, analytical approach is developed for calculating energy deposition and ionization fluctuations in volumes within ion-irradiated media which have dimensions as small as 1 nm. The method accounts for both direct ion interactions with the site and interactions of secondary electrons which are produced by ions in the surrounding medium. Particular attention is given to the way the contributions of the two types of events are combined. Since energy deposition fluctuations are simply related to the fundamental quantities ZD and yD employed in microdosimetry theory, this new approach provides a convenient means to obtain these parameters. Results obtained with the analytical method show good agreement with Monte Carlo charged-particle track-structure calculations of yD for 0.5 to 20 MeV protons incident on spherical sites of water vapor with diameters ranging from 1 nm to 10 microns. In contrast to Monte Carlo techniques, the analytical method does not depend on knowing the intricacies of single ion and electron interactions with the target and can therefore be adapted to calculations with heavier incident ions and different target materials, including those of the condensed state.

Electrons↗

PubMed1992

Anatomical considerations of posterior tibialis tendon entrapment in irreducible lateral subtalar dislocation.

Irreducible lateral subtalar dislocation is associated with posterior tibialis tendon entrapment. Mulroy and Leitner have proposed conflicting theories regarding the exact mechanism of tendon entrapment. Cadaveric analysis of lateral subtalar dislocation supported Leitner's contention that tearing of the flexor retinaculum promotes posterior tibialis tendon entrapment. Retinacular disruption allowed tendon subluxation over the medial malleolus and talar head to the entrapped position. Entrapment of the flexor digitorum longus only occurred in the Leitner model. When the flexor retinaculum and deep posterior compartment fascia were preserved, the muscle failed at the musculotendinous junction. Flexor hallucis longus entrapment could not be produced in either experimental model. Plantarflexion of the great and lesser toes, noted on clinical presentation, is caused by functional lengthening of the route coursed by the flexor digitorum longus and flexor hallucis longus.

Cadaver↗

PubMed1991

Immunoreactivity of CD45, a protein phosphotyrosine phosphatase, in Alzheimer's disease.

Both protein kinases and phosphoprotein phosphatases are important components of signal transduction systems in cells. Recent studies in Alzheimer's disease (AD) have shown abnormal protein phosphorylation in the cortex suggesting an alteration in these enzymes. In the present study, an antibody against CD45 was used to analyze the status of this protein phosphotyrosine phosphatase in AD. We studied and quantified the immunohistochemical and immunochemical distribution of this integral membrane protein in control and AD brain. We found that anti-CD45 immunostained the great majority of microglia, both resting and activated. These cells were Ricinus communis agglutinin I positive and glial fibrillary acidic protein and neurofilament negative. The AD frontal cortex showed a 35% (P less than 0.01) increase in the number of anti-CD45 immunoreactive microglia as compared with controls. These results were consistent with the immunoblot quantification of CD45 immunoreactivity following native gel electrophoresis. In AD, 30% of the CD45-immunostained microglia were clustered in the neuritic plaques (about six per plaque) while the remaining 70% were scattered in the neuropil. The AD hippocampus showed an increase in CD45-immunoreactive microglia in the molecular layer of the dentate gyrus. At the ultrastructural level, CD45 immunoreactivity was localized exclusively to the plasma membrane of the microglia. The presence of the anti-CD45 immunoreactivity in microglia suggests the possibility that they may require the presence of CD45 as a cell surface receptor which may regulate cell function through modulation of intracellular signaling.

Aged↗

PubMed1991

Unilateral lumbosacral facet joint dislocation associated with vertical shear sacral fracture.

An 18-year-old woman involved in a motor vehicle accident sustained a vertical shear fracture of the sacrum accompanied by unilateral dislocation of the L5-S1 joint. Evaluation of the patient's injuries was defined by computed axial tomography. Through a posterior midline incision, open reductions of the dislocated L5-S1 joint and of the sacral fracture were performed. Reduction was followed by anterior stabilization of the symphysis pubis. The patient remained neurologically intact after surgery.

Adolescent↗

PubMed1990

Pelviscopy for ectopic pregnancy: a safer and quicker alternative.

Treating ectopic pregnancy with laparoscopy requires special training, but it results in decreased morbidity, discomfort, and pain; reduced recuperative time; and lower cost to the patient and hospital. Many conditions mimic ectopic pregnancy. Therefore, to make the diagnosis, a complete history must be taken, a careful physical examination must be performed, and certain diagnostic tests must be made. Contraindications include bowel obstruction, ileus, abdominal hernia, peritonitis, brisk intraperitoneal bleeding, diaphragmatic hernia, severe cardiac disease, extremes of body weight, previous surgery, or presence of a large abdominal mass.

Female↗

PubMed1988

Electromyographic evaluation of the inguinal region in patients with hernia of the groin.

Electromyographic studies were performed upon 25 patients prior to repair of primary inguinal hernias. Abnormality signifying partial denervation was found in only three patients and did not correlate with prior appendectomy, other abdominal operations or type of hernia. The low frequency of this abnormality in this small series of patients is taken as evidence that relative denervation does not play a significant role in the development of primary inguinal hernia.

Adult↗

PubMed1987