Biomedical subjects
Publications and source records attributed to B Shah.
We report an unusual case of a transitional cell carcinoma arising in a bladder diverticulum presenting as a giant abdominal mass and acute urinary retention. We have reviewed the literature and discuss the aetiology, diagnosis, and treatment of tumours arising in vesical diverticula.
Laryngeal adduction for swallowing chiefly involves contraction of the thyroarytenoid and lateral cricoarytenoid muscles to seal the glottic chink. Vocal cord elongation supplements closure through cricoarytenoid activation. Relaxation of the posterior cricoarytenoid muscle is also involved in the swallowing process. Recent interest has focused on stimulating the laryngeal nerves to protect the lower airway from conditions where normal muscular coordination may be disrupted (e.g., in aspiration following stroke). Unfortunately, electrical stimulation results in a generalized contraction of all the dependent intrinsic laryngeal muscles because the larger, more excitable axons fire before their smaller counterparts can be activated. In the physiological state, however, the smaller fibers are recruited first. The current study focuses on electronic manipulation of force in the glottic muscles involved in deglutition. We used a stimulator that could selectively activate the intrinsic laryngeal muscles based on their specific motor unit architectures. In 5 dogs, the circuit recruited the axons in the recurrent and superior laryngeal nerves from small to large. The muscles were identified according to the differential recruitment rates of their compound muscle action potentials as they appeared on the graph. The smaller axons in the thyroarytenoid recruited faster than the large ones found in the lateral cricoarytenoid muscles, with intermediate figures observed with the cricothyroid. The posterior cricoarytenoid presented with the slowest recruitment rates, as expected from this muscle's highest contingent of larger motor units. Latencies between the onsets of stimulations and muscle saturations also appeared stable. This approach to manipulating glottic force saves energy because it allows stimulating the adductory muscles with minimal interference from their abductor antagonist.
OBJECTIVES: To determine risk factors for Serratia marcescens infection or colonization, and to identify the source of the pathogen and factors facilitating its persistence in a neonatal intensive-care unit (NICU) during an outbreak. DESIGN: Retrospective case-control study; review of NICU infection control policies, soap use, and handwashing practices among healthcare workers (HCWs); and selected environmental cultures. SETTING: A university-affiliated tertiary-care hospital NICU. PATIENTS: All NICU infants with at least one positive culture for S marcescens during August 1994 to October 1995. Infants who did not develop S marcescens infection or colonization were selected randomly as controls. RESULTS: Thirty-two patients met the case definition. On multivariate analysis, independent risk factors for S marcescens infection or colonization were having very low birth weight (< 1,500 g), a patent ductus arteriosus, a mother with chorioamnionitis, or exposure to a single HCW. During January to July 1995, NICU HCWs carried their own bottles of 1% chlorxylenol soap, which often were left standing inverted in the NICU sink and work areas. Cultures of 16 (31%) of 52 samples of soap and 1 (8%) of 13 sinks yielded S marcescens. The 16 samples of soap all came from opened 4-oz bottles carried by HCWs. DNA banding patterns of case infant, HCW soap bottle, and sink isolates were identical. CONCLUSIONS: Extrinsically contaminated soap contributed to an outbreak of S marcescens infection. Very-low-birth-weight infants with multiple invasive procedures and exposures to certain HCWs were at greatest risk of S marcescens infection or colonization.
OBJECTIVE: To review the literature over the past decade on mental retardation, particularly as regards its definition, prevalence, major causes, and associated mental disorders. METHOD: A computerized search was performed for articles published in the past decade, and selected papers were highlighted. RESULTS: The study of mental retardation has benefited considerably by advances in medicine generally and by developments in molecular neurobiology in particular. Increasing awareness of psychiatric comorbidity in the context of intellectual disability highlights the need for studies of the phenomenology and treatment of mental disorders in this population. CONCLUSIONS: Although the study of developmental disorders has advanced significantly over the past decade, considerable work remains. Mental retardation is a model for the utility of the biopsychosocial approach in medicine.
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The most common health problems of the elderly are related to chronic disease as a result of increase in life expectancy. In India, sporadic data have been collected on different health problems of the elderly. While epidemiologic studies specifically targeted at the elderly population are sparce, the Indian Council of Medical Research (ICMR) has carried out several studies on specific chronic disorders such as hearing impairment, blindness, cardiovascular diseases, cancer etc. The data from these studies covering the aged population have been utilised to provide a chronic morbidity profile of the elderly. Based upon the population estimates, the disease load in the Indian elderly population has been estimated. Hearing impairment is the most common morbidity, followed by visual impairment. The common risk factors associated with these chronic disease, are reported upon, and measures for intervention are suggested, wherever feasible. The paper does not cover common morbidities, such as locomotor, urinary and sleep disturbances, which have been reported in other surveys. The availability of population based data from India, and derives the disease burden due to chronic diseases in the elderly is emphasised. Such data can be used to generate the pattern of health problems in the elderly, for initiating appropriate intervention strategies and for fixing priorities for planning health care services amongst the elderly.
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The specific performance of intrinsic laryngeal muscles has been difficult to evaluate, especially in living subjects. To reproduce natural contractions, we artificially induced orderly recruitment of their innervating axons according to the size principle. In 5 dogs, both recurrent laryngeal nerves (RLNs) were stimulated with 50 through 10 Hz, 300 to 1000 microA currents while 600 Hz, 1000 to 0 microA decreasing blocking currents were administered. Surface electromyography electrodes placed on the thyroarytenoid, posterior cricoarytenoid, and lateral cricoarytenoid muscles were used to determine the amplitudes (in mA) of compound muscle action potentials. There was a highly statistically significant difference (P<.004) between the thyroarytenoideus which had the fastest rate of recruitment (8.38%), and posterior cricoarytenoideus, which had the slowest (4.81%). There was an intermediate recruitment rate (6.72%) of the lateral cricoarytenoideus, a divergence attributed to a more equal distribution in fast and slow types of myofibers and a smaller sample. We submit that RLN axons can be recruited in an orderly manner according to their sizes and that the rates are unique to the muscle classes they innervate. The parameters defining these contraction patterns may offer key information for laryngeal pacing.
Diseases from the major pathophysiological subgroups, including inflammatory, infectious, neoplastic, autoimmune, and metabolic disorders, can present in a very similar clinical manner. The importance of generating a broad differential diagnosis is supported by a case in which an 80-year-old white man presented with a verrucous plaque on the tip of his nose. The appropriate differential diagnosis for such a lesion as well as an overview of the disease diagnosed, North American blastomycosis, is presented.
Mucormycosis is a rare fungal disease commonly affecting individuals with diabetes mellitus, hematological malignancy, and immune deficiency. Isolated pulmonary mucormycosis is extremely rare. This article reports a case of isolated pulmonary mucormycosis that presented as a solitary cavity infiltrate in a patient with no underlying risk factors.
In a previous study we found that Schwann cells microtransplanted into the central nervous system rapidly dispersed from the transplantation site and became intimately associated with host grey and white matter. We have now investigated whether this migratory behavior of the donor Schwann cells is compatible with the production of stable, continuous anatomical cell tracks and whether such tracks can induce directional host axon growth. During the gradual withdrawal of a micropipette, highly purified suspensions of cultured adult peripheral nerve Schwann cells were continuously extruded to form a vertical column of cells extending for up to 4 mm through the thalamus and across the choroid fissure into the hippocampus of adult rat hosts. The donor Schwann cells were identified by immunohistochemistry for low-affinity nerve growth factor receptor, vimentin, and Rat 401. Although donor Schwann cells migrated into the host tissues, a large number remained along the axis of the injection track to form a column which was maintained for up to 3 weeks. From 4 days, increasing numbers of parallel, unbranching host RT97-positive axons entered the Schwann cell column in alignment with the long axis of the Schwann cells in the vertical tracks. The axons did not fasciculate directly with each other, but mingled diffusely with the Schwann cells. The Schwann cell tracks were able to convey host axons out of the dorsal thalamus, across the extracellular space of the choroid fissure, and into the ventral hippocampus. Thus, Schwann cells, transplanted in the form of elongated tracks, can establish bridges across boundary membranes in the brain and carry substantial numbers of nerve fibers from one area to another.
Sera from infants aged 5 to 11 months and from their mothers were used to investigate the level and duration of transplacentally derived measles antibody. The infants of foreign-born, inner-city mothers were more likely to have measles antibody and were less likely to get measles. Infants of foreign-born mothers, because they are less likely to respond to measles vaccine, may require different vaccine strategies than infants of mothers born in the United States.
A low cost, two-shell ferromagnetic shielded room large enough for a person to enter and prepare experiments was constructed for biomagnetic measurements. No aluminium or copper shell was used for eddy-current shielding. A high-permeability nickel-iron-molybdenum alloy (1.57 mm thick) was used for both ferromagnetic and eddy-current shieldings. The shielding factor was 60 dB at dc and 40 dB between 0.1 Hz and about 3 Hz. The eddy-current shielding due to the alloy alone provided a shielding factor of 55 dB at 30 Hz and 66 dB at 60 Hz. The shielding factor was sufficiently high in all the frequency range for biomagnetic measurements with a first-order superconducting gradiometer.
Matrix-assisted laser desorption ionization mass spectrometry (MALDI) has been investigated as a technique for the characterization of recombinant stem cell factor that had been covalently modified with polyethylene glycol (PEG) chains. The attachment of PEG chains produces a heterogeneous mixture of protein species that differ by 6000 Da. These differences in molecular weight could be readily determined by MALDI. The potential of MALDI as a general strategy for characterizing PEG-modified proteins is discussed.
Monoclonal antibody G10 recognises an epitope on microtubule-associated protein 1x, a developmentally regulated cytoskeletal protein expressed in immature axons of the central and peripheral nervous systems. Here we report that G10 can be used to identify the axonal projections of syngeneic embryonic (E14-E15) hippocampal cells microtransplanted by a minimally traumatic technique into intact adult host hippocampus.
A rare case of invasive squamous cell carcinoma of the urinary bladder developing 5 years after cadaveric renal transplant is described. The technical precautions to be taken while performing a radical cystectomy in such a situation is highlighted. This patient required chemotherapy in the post-operative period, and the role of chemotherapy in the presence of immunosuppressive therapy is discussed.
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