shukoor65/lab-rag-model huggingface dataset:
False-negative dipyridamole-thallium-201 myocardial imaging after caffeine infusion. The vasodilator effect of intravenously administered dipyridamole may be caused by an increase in endogenous plasma adenosine levels. We evaluated the effect of caffeine, an adenosine receptor antagonist, on the diagnostic results of dipyridamole-201Tl myocardial imaging in eight patients with coronary artery disease. Caffeine infusion significantly attenuated the dipyridamole-induced fall in blood pressure and the accompanied increase in heart rate. The infusion of dipyridamole alone resulted in chest pain and ST-segment depressions on the electrocardiogram in four patients, whereas none of these problems occurred when the tests were repeated after caffeine. In six of eight patients, caffeine was responsible for false-negative dipyridamole-201Tl tests. Semiquantitive scores of the dipyridamole-induced 201Tl perfusion defects were decreased by caffeine from 9.0 +/- 0.9 to 2.0 +/- 1.1 points (p less than 0.05). Computerized analysis revealed a caffeine-mediated reduction in the percent reversibility of the images from 46% +/- 16% to 6% +/- 10% (p less than 0.05). We conclude that the use of caffeinated products prior to dipyridamole-201Tl testing may be responsible for false-negative findings.
Investigation of varicella-zoster virus infection by polymerase chain reaction in the immunocompetent host with acute varicella. A polymerase chain reaction (PCR) method developed to detect varicella zoster virus (VZV) in clinical samples is based on amplifying sequences of viral gene 31, the coding region for glycoprotein II. Its sensitivity was evaluated by amplification from plasmid VZV DNA containing VZV gene 31; 45 copies were detected in 1 microgram of human DNA. In testing within 24 h after the onset of varicella exanthem, 21 (75%) of 28 lesion samples were positive by VZV PCR, whereas VZV was isolated from only 21% by a standard tissue culture method. Only 1 (3.3%) of 30 samples of oropharyngeal secretions but peripheral blood mononuclear cells from 8 (67%) of 12 patients were positive. The sensitivity and specificity of the VZV PCR method indicates its usefulness for investigating the pathogenesis of VZV infection. Direct contact with cutaneous lesions rather than respiratory secretions may be the most important route of VZV transmission from healthy individuals with acute varicella.
Lack of association between neutropenia and the incidence of bacteremia associated with indwelling central venous catheters in febrile pediatric cancer patients. To assess the incidence of bacteremia in pediatric cancer patients with indwelling central venous catheters with fever, we reviewed the records of all 67 such patients sequentially admitted during a 10-month period at our institution. There were a total of 140 episodes of fever in these 67 patients. In 55 of the episodes (39%) patients were nonneutropenic (absolute neutrophil count, greater than 500/mm3); 85 episodes (61%) were associated with neutropenia. Twenty-four percent of all episodes of fever in nonneutropenic patients were related to bacteremia vs. 9.5% of episodes of fever in the presence of neutropenia (P less than 0.05). When clinical evidence of an exit site infection was absent, the incidence of bacteremia in the neutropenic and nonneutropenic groups was similar (11% in the neutropenic group; 10% in the nonneutropenic group). We conclude that bacteremia is frequently observed in febrile pediatric cancer patients with indwelling venous catheters who are not neutropenic, particularly if there is clinical evidence of an exit site infection. Thus empiric antibiotic therapy is warranted in all pediatric oncology patients with indwelling catheters who develop fever.
High recovery of Haemophilus influenzae and group A streptococci in recurrent tonsillar infection or hypertrophy as compared with normal tonsils. One hundred and twenty-six patients who underwent tonsillectomy because of recurrent acute tonsillitis, tonsillar hypertrophy or sleep apnoea were evaluated by tonsillar core culturing. The sleep apnoea patients served as controls, since none of them had tonsillar hypertrophy at ENT examination or any history of recurrent acute tonsillitis, and thus their tonsillar core flora could be regarded as normal. The isolation rate of H. influenzae was much lower among sleep apnoea controls (2.7 per cent) than among either the patients with recurrent acute tonsillitis (20.3 per cent) or those with tonsillar hypertrophy (36.7 per cent) (p less than 0.05), as was that of group A streptococci, 5.4 per cent versus 16.9 and 20 per cent, respectively (though the latter differences were not statistically significant). The isolation frequencies of B. catarrhalis, pneumococci, group C and G streptococci did not differ between the three groups. The high tonsillar core recovery rates of H. influenzae and group A streptococci both in patients with recurrent acute tonsillitis and in those with tonsillar hypertrophy, as compared with normal controls, suggests the possible involvement of these bacteria in both conditions.
Autoerotic death. A definition. A definition of autoerotic death is suggested that restricts the use of this term to accidental deaths that occur during individual, usually solitary, sexual activity in which a device, apparatus, or prop that was employed to enhance the sexual stimulation of the deceased in some way caused unintended death. The case of the autoerotic asphyxial death of a 48-year-old man is reported in order to demonstrate the application of this definition.
Cholestasis in patients with the acquired immune deficiency syndrome: comparison between ultrasonographic and cholangiographic findings. Cholestasis in patients with acquired immune deficiency syndrome was systematically investigated by ultrasonography and endoscopic retrograde cholangiopancreatography. The two procedures were found to be complementary, and showed similar results in 56.2% of the cases. Ultrasonography was superior in detecting common bile duct wall thickening, whereas endoscopic retrograde cholangiography was superior in demonstrating intrahepatic narrowing of the biliary tract.
Inaccuracy of pulse oximetry in patients with severe tricuspid regurgitation. The accuracy of pulse oximetry was studied in a group of patients with severe tricuspid regurgitation. Measurements of arterial oxygen saturation from a finger and an ear probe were compared with those from a radial arterial blood sample analysed in vitro. Lower values were obtained using the pulse oximeter; the difference ranged from +2% to -11%. The discrepancies between pulse oximeter and laboratory oximeter readings were greater in this group of patients than in a control group who did not have tricuspid regurgitation. There was, however, no correlation between the magnitude of this discrepancy and either the peak central venous pressure or the venous pulse pressure.
Subpopulations of B cells in germinal centers. III. HJ6, a monoclonal antibody, binds globoside and a subpopulation of germinal center B cells. To identify surface Ag uniquely expressed on human germinal center B cells, we produced a mouse mAb, HJ6. When tonsillar lymphocytes were examined, HJ6 did not label T cells and labeled only about half of PNA+ B cells that were HK23-. HJ6 did not label mononuclear cells from peripheral blood, splenocytes, and any of 29 cell lines including 23 B cell lines. This binding pattern of HJ6 was very similar to that of a mAb named 5B5. It was shown previously that 5B5 bound a glycolipid named CTH (CD77) and its Ag was expressed on HK23- PNA+ tonsillar lymphocytes and Burkitt's lymphoma cell lines. Despite the similarity, HJ6 differed from 5B5: HJ6 did not stain Burkitt's lymphoma cell lines and stained PNA+ tonsillar lymphocytes in the presence of a large concentration of galactose. When its binding to isolated glycolipids was studied, HJ6 was found to bind globoside and Forssman Ag and not to other glycolipids including CTH. When its binding to neutral glycolipids extracted from tonsillar lymphocytes was studied, HJ6 bound only globoside; Forssman Ag was not detected in tonsillar lymphocytes. Taken together, we conclude that globoside is a B cell Ag expressed on a subpopulation of germinal center B cells.
Techniques for application of tissue adhesive for corneal perforations. We describe a modified technique of using cyanoacrylate adhesive to seal corneal perforations. Easily performed at the slit lamp, its advantages over previously described methods include a smooth, contoured collagen surface overlying the adhesive, which is easily wet by the tear film. Even greater comfort and protection are provided by the addition of a hydrophilic bandage lens or collagen shield.
Inhibitory effects of procainamide on sympathetic nerve activity in humans. In experimental animals, procainamide causes hypotension and reductions in efferent vasoconstrictor sympathetic outflow that may result from ganglionic blockade or central nervous system sympathetic inhibition. To test the hypothesis that procainamide decreases sympathetic nerve activity (SNA) in humans, we recorded postganglionic SNA in seven normal subjects in the baseline state and during infusions of procainamide HCl at 50 mg/min (loading) and 8 mg/min (maintenance). At the end of the loading infusion, mean arterial pressure (MAP) had decreased from 88.5 +/- 2.4 (mean +/- SEM) to 81.5 +/- 3.2 mm Hg (p less than 0.05), central venous pressure from 6.7 +/- 0.7 to 5.4 +/- 0.9 mm Hg (p less than 0.05), forearm vascular resistance (FVR) from 28 +/- 4.8 to 22.3 +/- 5.1 resistance units (p less than 0.05), and SNA from 259 +/- 47 to 94 +/- 26 units/min (p less than 0.05). These changes persisted during the maintenance infusion. Increased levels of SNA, FVR, and MAP provoked by the cold pressor test were reduced significantly by intravenous procainamide. In eight other subjects, intravenous procainamide HCl (15 mg/kg at 50 mg/min) caused dose-dependent inhibition of SNA that reversed as blood concentrations fell during drug washout. To determine if procainamide causes direct vasodilation, in nine subjects, graded infusions were delivered into the brachial artery at doses that produced no systemic effect. Ipsilateral FVR tended to increase during local intra-arterial infusion of procainamide. These data show that intravenous procainamide causes hypotension, vasodilation, and sympathetic withdrawal. Vasodilation does not result from a direct vasorelaxant effect of the drug.
Sepsis after coronary bypass grafting: evidence for loss of the gut mucosal barrier. Postoperative infections may originate from a patient's gastrointestinal tract. We studied infections after coronary artery revascularization. Three hundred twenty-nine patients underwent coronary artery revascularization from January 1987 to March 1990. Eight of the 329 (2.4%) died; none of the deaths were infection related. Fifty-five culture-proven infections were identified in 22 of 321 survivors (6.8%); 9 infections (16%) were gram-positive, 5 (9%) were fungal, and 41 (75%) were gram-negative. Site of infections were respiratory tract, 58%; urinary tract, 18%; blood, 13%; and mediastinum, 11%. Ninety-six percent of respiratory tract and all urinary tract infections were gram-negative or fungal. There was no significant difference between infected and noninfected groups in sex, age, smoking history, preoperative hematocrit or leukocyte count, serum albumin level, or time on extracorporeal bypass. The infected group required intubation and nasogastric suction for a significantly longer time than the noninfected group (p less than 0.001). Time to enteral alimentation was significantly longer in the infected group (p less than 0.02). We were unable to correlate the number of infections with the lengths of intubation, nasogastric suction, or time to enteral alimentation. This study supports the concept of postoperative infections arising from bacterial translocation across the patient's gastrointestinal tract. The most significant risk factor is the length of the gastrointestinal tract disuse.
Phase I and pharmacokinetic trial of intraperitoneal etoposide in combination with the multidrug-resistance-modulating agent dipyridamole. Dipyridamole synergistically enhances the sensitivity of human ovarian carcinoma cells to etoposide in vitro. We conducted a phase I trial to investigate the feasibility of using dipyridamole to selectively increase the sensitivity to etoposide of tumors confined to the peritoneal cavity. Etoposide and dipyridamole were administered as a continuous 72-hour intraperitoneal infusion to 16 patients. The maximum tolerated dose of etoposide was 175 mg/m2 per day when administered with dipyridamole at a fixed dose of 24 mg/m2 per day. Dose-limiting toxic effects were leukopenia and thrombocytopenia. No other major toxic effects were observed. The free peritoneal etoposide and dipyridamole concentrations varied with the etoposide dose rate, reaching 218.9 and 25.3 microM, respectively, at an etoposide dose rate of 175 mg/m2 per day. The free etoposide and dipyridamole concentrations attained were well within the range needed for synergistic interaction.
Identification of 17 independent mutations responsible for human hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency. Complete hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency causes the Lesch-Nyhan syndrome, an X-linked, purine metabolism disorder manifested by hyperuricemia, hyperuricaciduria, and neurologic dysfunction. Partial HPRT deficiency causes hyperuricemia and gout. One requirement for understanding the molecular basis of HPRT deficiency is the determination of which amino acids in this salvage enzyme are necessary for structural or catalytic competence. In this study we have used the PCR coupled with direct sequencing to determine the nucleotide and subsequent amino acid changes in 22 subjects representing 17 unrelated kindreds from the United Kingdom. These mutations were confirmed by using either RNase mapping or Southern analyses. In addition, experiments were done to determine enzyme activity and electrophoretic mobility, and predictive paradigms were used to study the impact of these amino acid substitutions on secondary structure.
Involvement of neutrophils in postischaemic damage to the small intestine. Haemorrhagic mucosal lesions are produced during intestinal ischaemia and after reperfusion probably mediated by oxygen radicals. Oxygen radicals react with cell membrane lipids and induce cell damage by peroxidation and induce accumulation of polymorphonuclear leucocytes in the tissue. The aim of the study was to elucidate the involvement of polymorphonuclear leucocytes in post-ischaemic intestinal damage. Intestinal ischaemia was induced in cats by partial occlusion of the superior mesenteric artery. Samples from the small intestine were excised before and at the end of the two hour hypotensive period as well as 10 minutes and 60 minutes after reperfusion. Conjugated dienes, myeloperoxidase, and the purine metabolites were determined in the samples. The tissue was also examined histologically. Seven cats were treated before reperfusion with a monoclonal antibody (IB4) which inhibits leucocyte adherence to endothelial cells and its subsequent activation. After reperfusion myeloperoxidase activity increased and the ischaemic mucosal lesions worsened significantly. IB4 treatment prevented an increase in post-hypotensive myeloperoxidase activity and attenuated the normally observed severe mucosal lesions. We conclude that the severe post-ischaemic lesions are induced by polymorphonuclear leucocytes. Such mucosal injury may be appreciably reduced by blocking leucocyte adherence with IB4.
Genetic dissection of susceptibility to audiogenic seizures in inbred mice. Mice of some inbred strains, such as 21-day-old DBA/2J mice, have generalized convulsions when exposed to intense auditory stimulation. Analysis of susceptibility to audiogenic seizures in BXD recombinant inbred strains has demonstrated the influence of at least three loci. One locus, Asp-1, is located on chromosome 12 between Ah and D12Nyu1; another locus, Asp-2, is on chromosome 4, tightly linked to b. Here we report evidence that Asp-2 is located within an 8-centimorgan segment distal to b and that Asp-3 is linked to Mtv-1 on chromosome 7. We also present evidence that these three loci account for most of the heritable variation in susceptibility to audiogenic seizures in crosses of DBA/2J and C57BL/6J mice and that susceptibility to audiogenic seizures is influenced by genomic imprinting. Thus, genomic imprinting may complicate linkage and mapping studies and should be considered in analyses of complex modes of inheritance.
Genetic analysis of microtubule motor proteins in Drosophila: a mutation at the ncd locus is a dominant enhancer of nod. The nod (no distributive disjunction) and the ncd (non-claret disjunctional) mutations are both female-specific, recessive meiotic mutations in Drosophila melanogaster. Mutations at either locus show high frequencies of nondisjunction at meiosis I and both have been shown to encode kinesin-like proteins. Unlike the ncd mutation, which affects all chromosome pairs, the nod mutation affects only the disjunction of nonexchange chromosomes. Although both the nod and ncd mutations are fully recessive, females doubly heterozygous for nod and ncd mutations show levels of X and fourth chromosome nondisjunction that are 6- to 35-fold above those observed in control females. Exchange between chromosomes can suppress this effect; thus, only nonexchange chromosomes segregating via the distributive system are sensitive in double heterozygotes. Since the phenotype of double heterozygotes mimics that of the nod mutation, we infer that ncd is a dominant enhancer of nod. Failure of ncd to fully complement nod reveals the chromosome segregation machinery to be dosage sensitive. The probability that the distributive system will fail is enhanced in females simultaneously haploinsufficient at the nod and ncd loci.
Force-velocity and 30-s Wingate tests in boys at high and low altitudes. The effects of high altitude (HA, 3,700 m) on performance during a force-velocity test (maximal anaerobic power, MAnP) and a 30-s Wingate test (mean power, P) were studied in boys 7-15 yr of age. Forty-seven children acclimatized to HA were compared with 101 living at low altitude (LA, 330 m). They had the same good nutritional status and the same level of physical activities [average 5.4 +/- 1.1 (SD) and 5.2 +/- 1.9 h/wk at HA and LA, respectively]. They performed the two tests using the same calibrated cycle ergometer. For the Wingate test, O2 uptake (VO2) during the 30 s and the peak of blood lactate concentration ([L]p) during the recovery were also measured. No difference in MAnP was observed between HA and LA. P, [L]p, and VO2 were lower at HA. This suggests that the altitude of 3,700 m did not affect the performance of the force-velocity test but reduced that of the Wingate test. This decrease in P was linked to a lower participation of glycolysis and aerobic metabolism. The latter is related to a reduced aerobic performance at HA. In addition, the slopes of the relationships between age and MAnP, P, and [L]p were the same at HA and LA, indicating that chronic hypoxia did not alter the development of the anaerobic metabolism during puberty.
Role of a soy-based lactose-free formula in the outpatient management of diarrhea. The introduction of a soy-based, lactose-free formula during the acute phase of diarrheal illness in infants has been shown to reduce stool output and duration of diarrhea in hospitalized patients. In the United States, most infants with acute diarrhea are treated as outpatients. In the present study, infants with diarrhea who were treated as outpatients were randomly assigned to receive either a soy-based, lactose-free formula alternating with oral rehydration solution from the beginning of therapy ("early feeding") or oral rehydration solution alone for the first 24 hours of therapy, followed by a soy-based, lactose-free formula alternating with oral rehydration solution (control group). Twenty-nine infants were randomly assigned to the early-feeding group and 27 to the control group. Twenty-one (72%) of 29 in the early-feeding group resolved their diarrhea at the end of 48 hours of therapy compared with 12 (44%) of 27 in the group fed oral rehydration solution only (P = .02). It is concluded that the introduction of a soy-based, lactose-free formula from the beginning of therapy for acute diarrhea in children treated as outpatients is safe and may shorten duration of diarrhea while maintaining adequate caloric intake.
Identification of spirochetes related to Treponema pallidum in necrotizing ulcerative gingivitis and chronic periodontitis. BACKGROUND. Spirochetes are commonly associated with periodontal disease, but it is not known whether these treponemes are pathogenic or merely opportunistic. We sought to determine whether spirochetes present in periodontal disease share antigens thought to be unique to spirochetes that are known pathogens. METHODS. We examined dental plaque from 24 healthy subjects, from ulcerative sites in 17 patients with ulcerative gingivitis, and from areas of involvement in 19 patients with chronic periodontitis, using an immunocyto-chemical technique with monoclonal antibodies against pathogen-specific determinants on 47-kd and 37-kd molecules from Treponema pallidum subspecies pallidum. Serum was tested against T. pallidum by immunoblotting and by serologic assays for syphilis. RESULTS. Spirochetes with a pathogen-specific epitope on a 47-kd molecule were not found in plaque samples from any of the 24 healthy subjects, but they were identified in plaque samples from 11 of 17 patients with ulcerative gingivitis (P less than 0.001) and from 10 of 19 patients with periodontitis (P less than 0.01). Monoclonal antibodies directed against a 37-kd molecule reacted with spirochetes in plaque samples from 1 of 14 controls, from all 11 patients with gingivitis from whom samples could be obtained (P less than 0.001), and from 14 of 19 patients with periodontitis (P less than 0.001). Five of 18 normal subjects had IgG against 47-kd and 37-kd molecules, but none had IgG against 14-kd or 12-kd molecules from T. pallidum subspecies pallidum. Among 19 patients with ulcerative gingivitis, IgG was identified against 47-kd molecules in 15, against 37-kd molecules in 12, against 14-kd molecules in 4, and against 12-kd molecules in 15. CONCLUSIONS. The spirochetes found in dental plaque from patients with ulcerative gingivitis or chronic periodontitis have antigens that are thought to be unique to pathogenic treponemes. This close antigenic relation suggests that T. pallidum or a closely related organism may be involved in the pathogenesis of periodontal disease.