Search PubMed⌕ Search

Biomedical subjects

B Singh

Publications and source records attributed to B Singh.

At least 1,063 records · Page 59Linked to original sources
PubMedDate not supplied

Outcome differences in younger and older patients with laryngeal cancer: a retrospective case-control study.

PURPOSE: Younger or older age has a significant impact on the outcome of patients with head and neck cancer. However, the data regarding outcomes based on age are conflicting. The aim of this article is to determine the impact of age on the outcome of laryngeal cancer. MATERIALS AND METHODS: A retrospective study was performed including all patients with squamous cell carcinoma of the larynx for over a 9-year period. The patients were divided into 3 groups based on age. The younger age group included patients 40 years of age and younger, the older group included patients over 80 years of age, and the remaining patients served as the control group. Descriptive statistics were used to summarize study data. Nonparametric quantitative and qualitative analyses were performed using the Mann-Whitney U test and Fisher's exact test, respectively. Survival analysis was performed using the generalized Wilcoxon test. The Cox proportional hazards model was used for multivariate analysis. RESULTS: Of the 209 patients with laryngeal carcinoma presenting to our institution over a 9-year period, 20 (10%) were < or =40 years and 15 (7%) were > or =80 years of age. No differences in TNM stage at presentation, treatment, or treatment-associated complications were observed based on age. However, younger patients were less likely to report tobacco (50%; P < .001) or alcohol (57%; P = .03) use and more likely to have human immunodeficiency virus infection (50%; P< .001). Older patients showed a trend toward having a worse baseline medical status. Recurrence was significantly more common in older patients (P = .02) and cause-specific survival significantly poorer for both younger and older patients (P = .002). CONCLUSIONS: The presentation and outcome of laryngeal cancer is influenced by the age at presentation. The differences may be related exact reason for the observed survival differences needs to be determined.

Adult↗
PubMedDate not supplied

Transesophageal echocardiography in the presence of left atrial calcification.

Calcification of left atrial walls is a rare finding that has been reported to hamper visibility of intracardiac structures during transesophageal echocardiography because of the posterior location of the left atrium. We report a case of severe mitral stenosis associated with heavy left atrial calcification in which we could obtain good quality transesophageal imaging in spite of such a calcification. We conclude that calcification of left atrial walls does not necessarily imply a limitation of transesophageal echocardiography.

Adolescent↗
PubMedDate not supplied

Anatomic considerations in relation to the maxillary nerve block.

BACKGROUND AND OBJECTIVES: To determine the length of the needle that should be used to reach the maxillary nerve after the lateral pterygoid plate has been contacted. METHODS: The study was conducted on patients and skulls. Patient study: The distances from skin at the midpoint of lower border of zygomatic arch to lateral pterygoid plate and to the point where a paresthesia in the distribution of maxillary nerve was obtained were measured in 75 patients. Osteologic study: The distance from the midpoint of lower border of zygomatic arch to lateral pterygoid plate and to a probe inserted from the orbital aspect through the inferior orbital fissure and pterygopalatine fossa into the foramen rotundum (representing maxillary nerve) was measured in 120 skulls. RESULTS: Patient study: The distance to the point where paraesthesia occurred was more than that to the lateral pterygoid plate by 0.21 cm on the right side and 0.22 cm on the left side. Osteologic study: The distance to the probe in the pterygopalatine fossa was more than the distance to lateral pterygoid plate by 0.13 cm on the right side and 0.14 cm on the left side. CONCLUSIONS: The needle should not be advanced by more than approximately 0.25 cm beyond the distance to the pterygoid plate while performing maxillary nerve block by the lateral extraoral approach.

Adult↗
PubMedDate not supplied

Effects in rats and guinea pigs of six-month exposures to sulfuric acid mist, ozone, and their combination.

Rats and guinea pigs were exposed to 0.5 ppm O3, 10 mg/m3 sulfuric acid (H2SO4) mist, or their combination for 6 h/d, 5 d/wk for 6 mo. Microscopic alterations were seen in the lungs of guinea pigs exposed to O3 alone or in combination with H2SO4 mist. No other microscopic lesions were present in either rats or guinea pigs. No biologically meaningful synergistic effects were noted in animals exposed to the combination of O3 and H2SO4 mist.

Aerosols↗
PubMedDate not supplied

Expression of human 60-kD heat shock protein (HSP60 or P1) in Escherichia coli and the development and characterization of corresponding monoclonal antibodies.

Human P1 protein, which is the homolog of the 60- to 65-kD heat shock "common" antigenic protein of numerous pathogenic organisms (synonyms: HSP60, GroEL homolog, or chaperonin), has been expressed to high level in Escherichia coli cells. A large number of well-characterized deletions of this protein spanning the entire sequence have been constructed and expressed. Methods to purify recombinant human HSP60 protein and its deletions from E. coli have been worked out. In addition, monoclonal antibodies to the human HSP60 protein have been raised and partially characterized. The availability of these materials should greatly aid in understanding the role of this highly conserved and immunologically important protein in autoimmune diseases and in cell structure and function.

Amino Acid Sequence↗
PubMedDate not supplied

Catheter related bacterial infections mimic reactions to exogenous pyrogens during hemodialysis.

Pyrogenic reactions are characterized by fever, chills, hypotension, or a combination of these developing during or shortly after hemodialysis in a previously asymptomatic patient. The temporal association with treatment implicates exposure of the patient's blood to bacterial pyrogens from contaminated dialysate or a reused dialyzer. Routine body temperature monitoring is recommended to detect these exposures. The current study was prompted by the appearance of several symptomatic febrile episodes in patients who were asymptomatic and afebrile before treatment with high-flux hemodialysis. During a 6 month period, temperatures were measured with a digital oral thermometer before and after 9,605 high-flux hemodialyses in 163 patients. Elevations above 100 degrees F (37.8 degrees C) were observed during or after 33 dialyses in 15 patients. In 18 of these dialyses, the temperature was also elevated before treatment began. Four patients who had no symptoms or fever before dialysis accounted for febrile reactions during 11 of the remaining 15 dialysis treatments. Fever was accompanied by rigors during most of the episodes. Subsequent blood cultures grew Enterococcus faecalis (two), Enterobacter cloacae (two), and Pseudomonas aeruginosa and cepacia (one). All four patients had indwelling silastic double lumen venous catheters (PermCaths), all responded to intravenous antibiotics, and all required eventual removal of the catheter. The apparent precipitation of sepsis by dialysis indicates that shear forces caused by high pulsatile blood flow through the catheter may dislodge organisms that have colonized the lumen. Intraluminal instillation of antibiotics is suggested as a preventative measure.

Adult↗
PubMedDate not supplied

Beneficial effects of amiodarone pretreatment on early ischemic ventricular arrhythmias relative to infarct size and regional myocardial blood flow in the conscious dog.

The effects of chronic pretreatment with amiodarone on ischemic ventricular arrhythmias were evaluated in fully conscious instrumented dogs. In control dogs (n = 14) with large myocardial infarcts, early (first 30 min) ventricular arrhythmias occurred in a bimodal distribution with peaks at 3-5 min and at 12-25 min, with only the former associated with epicardial conduction delay. Ventricular fibrillation occurred equally frequently during each peak of early ventricular arrhythmias. Amiodarone (30 mg/kg daily) for 3-4 weeks had no significant effect (n = 11) on anatomic infarct size (28 +/- 6 vs. 30 +/- 5% of left ventricular weight) nor on collateral blood flow in the center of the infarct (19 +/- 11 vs. 15 +/- 7 ml/min/100 g of tissue) or on the ratio of endocardial/epicardial perfusion (0.23 +/- 0.19 vs. 0.28 +/- 19). Despite significant lengthening of peak epicardial conduction delay (191 +/- 20 to 239 +/- 81 ms, p less than 0.05), the frequency of early ventricular arrhythmias, especially during the second peak of ectopic activity, were markedly attenuated by amiodarone pretreatment, with the extrasystole-free intervals often being as long as 6 h. The incidence of ventricular fibrillation was 9% in the treated animals compared with 29% in the controls. In the control animals, arrhythmias always supervened when epicardial fractionation was significant, and no ectopy-free interval was present in the first 6 h following coronary occlusion. The data indicate that chronic amiodarone pretreatment exerts a beneficial effect on the frequency and severity of such ventricular tachyarrhythmias, with reduction in the incidence of ventricular fibrillation and ectopic activity in the early phases following coronary occlusion.

Amiodarone↗
PubMedDate not supplied

Outbreak of mycotic tracheitis in domestic fowl.

An outbreak of mycotic tracheitis was observed in 8000 2-month-old, female White Leghorn birds. The birds were showing difficult respiration and there was mortality of 7-8 birds daily in the flock. On post-mortem examination of the affected birds, the trachea was found to be occluded with a white caseous mass. Microscopically hyphae were found invading the tracheal epithelium, cartilage and serosal layer along with infiltration of macrophages and lymphocytes. Aspergillus fumigatus was isolated in pure culture from the trachea. The birds responded to oral copper sulphate treatment. The ubiquitous occurrence of the organism and the conditions of the harvesting season have been found to be responsible for the outbreak of the disease.

Animals↗
PubMedDate not supplied

Partial seizures presenting as life-threatening apnea.

Apneic episodes, quite common in newborns, are considered rare after age 1 month, when gastroesophageal reflux, cardiac arrhythmias, idiopathic central apnea, and seizures become included in differential diagnosis. Determining the cause of apnea is important as treatment differs significantly and can be harmful; Caffeine given for presumed idiopathic central apnea is reported to have precipitated seizures in 2 patients with apneic seizures. Two cases of partial seizures presenting as apnea in infants were studied. Interictal EEG was normal in 1 and showed focal spikes in the other. Video EEG monitoring (16 channel) showed focal ictal discharge originating from temporal areas clearly preceding onset of apnea in both patients. Because therapeutic options are sometimes diametrically opposite and interictal EEGs are particularly unreliable for diagnosis, we recommend video-EEG monitoring if there is any doubt about the diagnosis before starting treatment in patients with apneic episodes.

Anticonvulsants↗
PubMedDate not supplied

Cytomorphologic patterns in Calmette Guerin bacillus lymphadenitis.

OBJECTIVE: To study the cytomorphologic patterns of Calmette Guerin bacillus (BCG) lymphadenitis and compare it to those of tuberculous lymphadenitis. STUDY DESIGN: A retrospective cytomorphologic study of 136 cases of clinically diagnosed BCG adenitis. All fine needle aspiration smears of lymphadenitis in the age group 2 months to 2 years during a three-and-half-year period were analyzed. RESULTS: Three distinct cytomorphologic patterns were seen in 112 cases. They were acid-fast bacilli in a necrotic background (62), granulomas with necrosis (47) and granulomas in a reactive lymphoid background (3). CONCLUSION: The cytomorphologic patterns in BCG lymphadenitis were similar to those seen in tuberculous lymphadenitis; however, an exudative response and high acid-fast bacillus positivity was seen more frequently in BCG lymphadenitis. Moreover, Ziehl-Neelsen staining helped to distinguish these cases from pyogenic abscesses.

BCG Vaccine↗
PubMedDate not supplied

Mucosal homeostasis: role of interleukins, isotype-specific factors and contrasuppression in the IgA response.

Oral ingestion of antigen elicits immune responses at mucosal sites where humoral immunity is largely due to antibodies of the IgA isotype. This is often accompanied by suppression of systemic responses to the same antigen, a state termed oral tolerance. This IgA response is regulated by interactions between T cell subsets found at IgA inductive tissues, i.e., the gut-associated lymphoreticular tissue (GALT) or Peyer's patches (PP). PP T helper (Th) cells support IgA responses, and interleukins 5 (IL-5) and IL-6 can augment secretion of this isotype. Subsets of Th cells may also express Fc receptors for IgA (Fc alpha R) and secrete Fc alpha R as an IgA-binding factor (IBF alpha). Membrane-derived Fc alpha R is a glycoprotein of 38,000 M.W. and this molecule induces selective increases in IgA secreting cells (as determined by the ELISPOT assay) in PP B cell cultures. Fc alpha R+ T cell lines have been shown to secrete IBF alpha as well as IL-5 both of which promote IgA synthesis. Recombinant IL-5 (rIL-5) and rIL-6 induce IgA synthesis mainly by PP B cell blasts, and principally act on surface IgA-positive (sIgA+) B cells for these responses. Another form of mucosal regulation is provided by T contrasuppressor (Tcs) cells, which abrogate oral tolerance when adoptively transferred to mice and restore systemic responsiveness to the antigen sheep erythrocyte (SRBC). Tcs cells from mice systemically primed with SRBC support IgM and IgG subclass responses, while Tcs cells from orally primed mice support IgM, IgG subclass and IgA anti-SRBC responses. These Tcs cells are CD3+, CD4-, 8- and are antigen-specific. These regulatory cells may use the gamma-delta (gamma-delta) form of T cell receptor for antigen recognition.

Animals↗
PubMedDate not supplied

Short report: differences in dihydrofolate reductase but not dihydropteroate synthase alleles in Plasmodium falciparum isolates from geographically distinct areas in Malaysia.

Dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr) alleles were typed in 67 Malaysian Plasmodium falciparum isolates. The isolates were collected from two geographically distinct locations: 51 from Sabah, Malaysian Borneo, where sulfadoxine/pyrimethamine (SDX/PYR) is used to treat uncomplicated malaria and 16 from Peninsular Malaysia where in vivo resistance to SDX/PYR has been reported. A total of seven dhps alleles were identified with no significant difference in allele frequency between the 2 populations. Two of the dhps alleles described here have not been previously reported. Four dhfr alleles were detected in 67 P. falciparum isolates. Eighty-seven percent of the isolates from the Peninsula, where clinical SDX/PYR failure has been reported, had dhfr alleles with triple point mutations while all of the isolates from Sabah had dhfr alleles with 2 or less point mutations. The difference in dhfr allele frequency between the two populations was highly significant. There was no correlation between in vitro PYR response and accumulation of dhfr point mutations.

Alleles↗