An unusual case of epidermolysis bullosa hereditaria letalis with cutaneous scarring and pyloric atresia.
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Biomedical subjects
Publications and source records attributed to M Vasquez.
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To determine the effect of antibiotic-induced nephrotoxicity on the renal accumulation of gallium, groups of ten Sprague-Dawley rats were given intraperitoneal injections of gentamycin, amphotericin, or neomycin for a period of 16--21 days. In all cases, mild to moderate nephrotoxicity was documented by one or more of the following parameters: serum creatinine, renal weight, urine volume (renal concentrating ability), light microscopy, and electron microscopy. In none of these cases was the renal accumulation of gallium increased over control values. Consequently, diffuse renal accumulation of gallium in patients with subclinical or mild nephrotoxicity is unlikely to be related to short-term treatment with aminoglycosides or amphotericin. In such cases, the physician should seek some other clinical explanation, such as infection.
In 35 patients aged 18 to 69 years (mean 48) with clinical, electrocardiographic, or electrophysiological evidence of normal sinus node function, the effect of intravenous propranolol (0.1 mg/kg) was assessed on 3 indices of sinus node function. The drug significantly prolonged sinus node cycle length (12%), slightly prolonged the corrected sinus node recovery time (15%), and slightly but insignificantly lengthened sinuatrial conduction time. Propranolol may be administered safely in patients with normal sinus node function without the fear of producing severe sinus bradycardia, sinuatrial block, sinuatrial pauses, or prolonged sinus asystole, after spontaneous or stimulation-induced conversion of a tachycardia.
This study describes a new method (NM) for estimation of sinoatrial conduction time (SACT), which utilizes constant atrial pacing (AP) instead of the premature atrial beats (PABs) used in the method reported in 1973 by Strauss et al. The SACTs were obtained by both methods in 20 patients. The SACT by the Strauss method (SM) was calculated as A2A3 minus A1A1. The NM consists of high right AP for a train of eight consecutive beats at rates less than or equal to 10 beats/min faster than the sinus rhythm. The interval between the last paced atrial electrogram (Ap) and the first escape atrial electrogram (A) of sinus origin (Ap-A) was measured along with several post pacing sinus cycles. The SACT by the NM was calculated as follows: SACT = Ap-A minus A1A1. The effect of AP at higher rates was also analyzed. In two patients, the SACT with the SM could not be defined, as all the A2A3 intervals were fully compensatory; with the NM the SACT was 217 and 320 msec. In the remaining 18 patients the SACT was obtainable by both methods. With SM, the SACT ranged 105--452 msec (mean 219 +/- 102 SD) and with the NM it was 85--492 msec (mean 201 +/- 112 SD), and the difference was statistically significant (P = 0.0162). The coefficient of correlation between the two methods was r = 0.97. During AP at faster rates, a rate related increment in Ap-A intervals and also post pacing sinus cycles was noted. This study describes a new and simple method for measurement of SACT in man.
Intrathoracic splenosis is a rare complication of combined diaphragmatic and splenic injury. This is the 79th reported case of splenosis and the seventh case of intrathoracic splenosis. That intrathoracic splenosis can mimic carcinoma of the lung on chest roentgenogram is exemplified by the similarity between the patient's chest film and that of his brother who died of lung cancer during the patient's hospital stay.
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The objective of this work is to compare the three-dimensional structures of "humanized" and mouse-human chimeric forms of a murine monoclonal antibody elicited against human gamma-interferon. It is also to provide structural explanations for the small differences in the affinities and biological interactions of the two molecules for this antigen. Antigen-binding fragments (Fabs) were produced by papain hydrolysis of the antibodies and crystallized with polyethylene glycol (PEG) 8,000 by nearly identical microseeding procedures. Their structures were solved by X-ray analyses at 2.9 A resolution, using molecular replacement methods and crystallographic refinement. Comparison of these structures revealed marked similarities in the light (L) chains and near identities of the constant (C) domains of the heavy (H) chains. However, the variable (V) domains of the heavy chains exhibited substantial differences in the conformations of all three complementarity-determining regions (CDRs), and in their first framework segments (FR1). In FR1 of the humanized VH, the substitution of serine for proline in position 7 allowed the N-terminal segment (designated strand 4-1) to be closely juxtaposed to an adjacent strand (4-2) and form hydrogen bonds typical of an antiparallel beta-pleated sheet. The tightening of the humanized structure was relayed in such a way as to decrease the space available for the last portion of HFR1 and the first part of HCDR1. This compression led to the formation of an alpha-helix involving residues 25-32. With fewer steric constraints, the corresponding segment in the chimeric Fab lengthened by at least 1 A to a random coil which terminated in a single turn of 310 helix. In the humanized Fab, HCDR1, which is sandwiched between HCDR2 and HCDR3, significantly influenced the structures of both regions. HCDR2 was forced into a bent and twisted orientation different from that in the chimeric Fab, both at the crown of the loop (around proline H52a) and at its base. As in HCDR1, the last few residues of HCDR2 in the humanized Fab were compressed into a space-saving alpha-helix, contrasting with a more extended 310 helix in the chimeric form. HCDR3 in the humanized Fab was also adjusted in shape and topography. The observed similarities in the functional binding activities of the two molecules can be rationalized by limited induced fit adjustments in their structures on antigen binding. While not perfect replicas, the two structures are testimonials to the progress in making high affinity monoclonal antibodies safe for human use.
A murine model of herpes simplex virus (HSV) infection was used to examine the roles of catecholamines and corticosterone in the restraint stress-induced suppression of viral immunity. Treatment of C57BL/6 mice with RU486, a glucocorticoid receptor antagonist, reversed the stress-induced diminution of cellularity in response to local HSV infection. Treatment of mice with both nadolol, a peripherally acting beta-adrenergic antagonist, and RU486 completely reversed the restraint stress-induced suppression of HSV-specific CTL activation. These findings demonstrate that both corticosterone and catecholamine-mediated mechanisms are operative in the stress-induced suppression of anti-viral cellular immunity.
A decision analysis model was constructed for comparison of early detection of asymptomatic genital chlamydial infection in women by the direct immunofluorescence antibody (DFA) test and the enzyme-linked immunosorbent assay (ELISA) with no intervention. Early-detection programs using the DFA test and ELISA were shown to be cost-effective in female populations where the prevalences of chlamydial infection exceeded 6% and 7%, respectively. Sensitivity analysis showed that the two most important factors were the probability of developing pelvic inflammatory disease and the cost of the test. The DFA method was more appropriate for an early-detection program because of its higher sensitivity.
The ultrastructure of an epithelioid hemangioendothelioma arising in the soft tissues of the neck of an 18-year-old female is reported. Comparison with similar tumors in other sites from the authors' electron microscopy files indicates that diffuse nonspecific intermediate filaments, pinocytotic vesicles, intracytoplasmic lumens, and pericytic cells are frequent but variable features of this neoplasm.
Until October 1991, zidovudine was the only licensed anti-HIV drug. Because zidovudine has limitations, the development of additional drugs is needed. One such drug is didanosine, which received FDA approval for patients who are intolerant of zidovudine or who have received prolonged zidovudine therapy. The authors provide an overview of the administration and adverse effects of didanosine, and recommend nursing interventions.