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Biomedical subjects

H Patel

Publications and source records attributed to H Patel.

At least 217 records · Page 12Linked to original sources
PubMed1985

Cystic fibrosis heterozygotes have normal autonomic innervation of the heart.

Five simple tests of autonomic nerve function based on measurements of cardiovascular responses to various stimuli were used to investigate possible autonomic dysfunction in obligate heterozygotes for cystic fibrosis. There were no significant differences between the heterozygotes and control groups in any of the tests, suggesting that cystic fibrosis heterozygotes have normal autonomic innervation of the heart.

Adult↗
PubMed1984

An allometric network model of craniofacial growth.

This study of cranial skeletal growth kinematics details the conceptual principles underlying the development of an allometric network model of such growth. This model is tested by the analysis of longitudinal rat and cross-sectional human growth data and by comparison of this model with a previously described allometric centered model. It is shown that the network model is superior to the centered model in three ways: (1) The allometric network model permits growth prediction when allometric constants are known; (2) the network model has significantly smaller errors than the centered model; and (3) the network model is capable of displaying growth kinematics of both the neural and facial skulls while in time there are marked transformations, such as relative rotations of two sets of cranial anatomic points.

Adolescent↗
PubMed1983

Statistical testing of an allometric centered model of craniofacial growth.

An allometric centered model of craniofacial growth was tested by several computer-assisted statistical methods on the pure longitudinal growth data of twenty-four close-bred female rats and on cross-sectional human cranial growth data. The study demonstrated that such a model was heuristic and, being incapable of exact definition, was deemed inappropriate for further use in modeling of craniofacial skeletal growth. The necessity for vigorous testing of any hypothesis concerning the modeling of craniofacial growth is stressed.

Adolescent↗
PubMed1983

Cytoplasmic body myopathy. Report on a family and review of the literature.

A 15-year-old girl who was seen for scoliosis presented with cardiorespiratory failure associated with a respiratory infection. She was found to have weakness predominant in the face, sternomastoid, proximal limb, respiratory, spinal and cardiac muscles. The serum creatine kinase level was slightly elevated and the electrocardiogram was abnormal. The electromyograph was consistent with a myopathy. The course was malignant. Her 14-year-old brother had similar findings and succumbed at the age of 14 and one-half years from cardiorespiratory failure. The mother had minimal weakness of proximal limb muscles since early life. The tendon reflexes were normal as was the serum creatine kinase level. The course was benign. On light microscopy the muscle biopsy in the girl showed fibre diameter variation, centrally placed nuclei, necrosis, fibrosis and cytoplasmic bodies. The muscle biopsy in the brother and mother had similar findings except that the inclusion bodies were not seen in the mother. On electron microscopy, the girl showed typical cytoplasmic bodies, involving predominantly type 1 fibres. The mother also had these structures. The literature is reviewed and the origin, pathogenesis and aetiology of the cytoplasmic body are discussed.

Adolescent↗
PubMed1983

Specificity and inhibition of the epidermal cell detachment induced by pemphigus IgG in vitro.

IgG isolated from sera of patients with pemphigus vulgaris (PV) has been shown to induce cell detachment when added to primary epidermal cell cultures (PECC). We studied the specificity of this phenomenon. IgG fractions were purified from the sera of five patients with PV and control IgG fractions from the sera of normal donors and patients with bullous pemphigoid (BP), systemic lupus erythematosus (SLE), and anti-AB blood group sera (anti-AB). IgG fractions were added to PECC either at initial plating (0 hours), at media change (48 hours), or sequentially at both times, and cell detachment was quantitated at 72 and 96 hours. Significant cell detachment occurred only when PV IgG was added to the growth media sequentially at 0 and 48 hours (p = 0.001), and this effect was dose-dependent for either dose. Substitution of an unrelated IgG (BP, SLE, or anti-AB) at either time points reduced cell detachment to near control values. Furthermore, cell detachment was inhibited by the addition of the proteinase inhibitors alpha 2 macroglobulin (70% inhibition of detachment), aprotinin (63% inhibition), soybean and lima bean trypsin inhibitor (62 and 64%, respectively), and pepstatin (49%), but not by the inhibitors chymostatin, leupeptin, or antipain. These data confirm that PV IgG induces increased cell detachment in PECC and shows that this effect is specific for PV IgG, is dose-dependent, and may be inhibited by certain proteinase inhibitors.

Animals↗
PubMed1982

Model experiments to study the stress distributions in a seated buttock.

Mechanical stress states that develop in the buttock during sitting may exceed tissue tolerance and lead to decubitus ulcer formation in susceptible patients, such as those with spinal cord injury. The danger of this complication can be reduced by using suitable cushions to minimize stress magnitudes and gradients within soft tissues. In this investigation, a two-dimensional physical model of the buttock-cushion system was developed to aid in cushion design. The model consists of PVC gel simulating flesh, cast around a wooden core simulating the ischium bone. A grid etched on the gel permits measurement of strains via photographs of the undeformed and deformed model buttock supported by various cushion materials. The displacement field is analyzed, using a finite strain theory and a strain energy function, to obtain the "tissue stresses'. In this manner, the performances of five clinically used cushion materials were compared with respect to the high stress regimes developed in the model buttock.

Buttocks↗
PubMed1982

Pseudomonas peritonitis and continuous ambulatory peritoneal dialysis.

In a population of 44 patients receiving continuous ambulatory peritoneal dialysis (CAPD) for a total of 591 patient months, there were 104 episodes of peritonitis. The organisms were gram-positive in 65.4%, gram-negative in 23.1%, and cultures of the dialysate were sterile in 11.5%. Pseudomonas aeruginosa was the most frequently encountered gram-negative organism, accounting for 38.5% of the gram-negative infections or 9.6% of all infections. In all cases of P aeruginosa peritonitis, aminoglycoside antibiotic therapy for up to four weeks failed to eradicate the infection, and all patients required removal of the Tenckhoff catheter because of the presence of a sinus tract infection. We conclude that P aeruginosa is the most frequent cause of gram-negative peritonitis in patients receiving CAPD. The presence of a sinus tract infection should be suspected in all patients in whom peritonitis secondary to this organism develops. Removal of the Tenckhoff catheter will be required to cure the peritoneal infection.

Adult↗
PubMed1981

Experience with the cerebral function monitor during deliberate hypotension.

Forty-five healthy patients (30 aged 15-46 yr and 15 aged 58-82 yr) undergoing various types of plastic surgery were studied during deliberate hypotension produced by a combination of ganglion- and beta-blockade, halothane, head-up tilt and positive end expiratory pressure. A Cerebral Function Monitor was used to assess the adequacy of cerebral perfusion. Cerebral activity did not undergo any significant change if the systolic arterial pressure was decreased gradually and maintained at approximately 60 mm Hg at heart level. However, a rapid decrease in pressure may depress cerebral activity in a reversible manner.

Action Potentials↗
PubMed1981

In vitro alterations of epidermal cell adhesion induced by temperature, substrate, and cations.

Epidermal cell-to-cell or basal cell-to-substrate adhesion in vitro, involves as yet, unknown mechanisms. The rate of attachment of newly dissociated neonatal mouse epidermal cells and the rate of keratinocyte detachment from preformed epidermal monolayers was investigated under a variety of experimental conditions. In the present investigation, we obtained the following results: (1) variables such as temperature, nature of substrate, and presence of cations in the growth medium were important in the initial cel-to-substrate attachment; (2) removal of Ca++ and Mg++ from the growth medium was associated with a very low attachment rate (less than 5% at 24 hr and 48 hr); (3) the initial cell-to-substrate attachment of epidermal cells decreased about 50% when maintained in medium deficient in either Mg++ or Ca++ indicating that both cations are important in the cell-to-substrate attachment; (4) keratinocyte-detachment from preformed monolayers increased in medium deficient in Ca++, Mg++ as well as in medium only deficient in Ca++. However, detachment in cultures maintained in Mg++ deficient medium was similar to controls. In conclusion, Ca++ is one factor that may regulate epidermal cell-to-cell and cell-to-substrate interactions in vitro. Mg++ appears to influence also in the initial attachment process of epidermal basal cells.

Animals↗
PubMed1980

Inhibitory interactions contributing to the ocular dominance of monocularly dominated cells in the normal cat striate cortex.

Experiments have been carried out to ascertain whether intracortical inhibitory processes influence the ocular dominance of monocularly dominated cells in the primary visual cortex of the normal cat. The GABA antagonist bicuculline has been iontophoretically applied to the cells studied to produce a localised block of inhibitory mechanisms acting on them. The ocular dominance of these cells was tested before, during, and after bicuculline application. In a sample of 42 cells studied, approximately 50% (19) showed a significant change in ocular dominance during bicuculline application. Some exclusively monocular cells became equally driven by either eye during bicuculline application. All the effects were reversible. Receptive field properties revealed in the non-dominant eye were not identical to those in the dominant eye. Evidence is presented to suggest that for some of the cells there is a selective GABA-mediated inhibitory process suppressing the non-dominant eye input. The possible implications of these data are discussed.

Animals↗
PubMed1979

Bullous pemphigoid antigen. II. Isolation from the urine of a patient.

This report concerns the isolation of bullous pemphigoid antigen from the nondialyzable urinary components of a patient with the disease. The isolation was accomplished by ion exchange chromatography and gel filtration. Pemphigoid antigen was found to be a basic glycoprotein that on SDS gel electrophoresis showed two major bands, one in the 18,000 m. w. region and the second with a m. w. of 74,000. Between these two bands, two additional bands appeared; one of 35,000 daltons and the other of 68,000 daltons. The 18,000 m. w. band was eluted from the gel and rerun on SDS gels. These gels showed the 18,000 m.w. band and also the appearance of the 35,000 and 74,000 m.w. bands. This finding indicates that urinary pemphigoid antigen may exist both as a single monomeric form and in polymeric aggregates.

Animals↗
PubMed1979

Transferring load to flesh: part IX. Cushion stiffness effects.

Stresses developed within flesh in contact with a cushion are examined analytically. Compressive, tensile, and shear stresses within flesh in proximity to a bone are given as a function of cushion stiffness (major parameter) and the overall Poisson's ratio of flesh (minor parameter). It is shown that an individual already sitting on a soft cushion receives relatively minor benefit when a still softer cushion is substituted. This result follows from the fairly flat (saturated) trend of both shear and tensile stress with respect to cushion stiffness, once the soft cushion domain (less than 10 PSI) is entered. Only flesh normal stress (compression) responds significantly to incremental changes of stiffness within the soft cushion range; reducing the cushion stiffness 50 percent will typically reduce local compressive stress by roughly 20 percent. While such a gain is real, it is also modest.

Bone and Bones↗