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Biomedical subjects

H Singh

Publications and source records attributed to H Singh.

At least 145 records · Page 8Linked to original sources
PubMed1997

Endoscopic ultrasound for peripancreatic masses.

BACKGROUND: Pancreatic neoplasms can be difficult to diagnose and stage preoperatively. Accurate staging allows the surgeon to select which patients can benefit from resection versus palliative therapy. Endoscopic ultrasound (EUS) with endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a diagnostic modality that provides visualization of peripancreatic tumors and their relationship to the surrounding structures as well as enabling cytologic diagnosis of the tumor and adjacent lymphadenopathy. METHODS: To define the role of this technique, a retrospective study was performed on 20 patients in the past year with peripancreatic tumors. RESULTS: Twelve men and 8 women ranging in age from 28 to 84 years (mean 67) were included in the study. Each patient underwent computed tomography followed by EUS-FNA, and the results were compared with operative findings or clinical course. The EUS-FNA findings included 10 pancreatic ductal carcinomas (50%), 5 pancreatitis (25%), 2 spindle cell neoplasms (10%), 1 cholangiocarcinoma (5%), 1 cystadenoma (5%), and 1 metastatic breast carcinoma (5%). Overall, EUS-FNA led to a significant change in the management of 12 patients (60%) through either diagnosing benign pathology, upstaging of the carcinoma, or determination that the peripancreatic mass represented a metastatic lesion. Five patients underwent resection of their peripancreatic tumors, and 3 patients had palliative procedures. Operative findings corresponded with EUS-FNA in all 8 patients. The 5 patients diagnosed with pancreatitis continued to be followed up for the possibility of a false negative FNA, but to date none have developed malignancy. CONCLUSIONS: EUS-FNA is a useful tool for the imaging and staging of peripancreatic tumors and will aid in the proper preoperative selection of patients who will benefit from resectional therapy.

Adult↗
PubMed1997

Cytochromes P450 (CYP) in tropical fishes: catalytic activities, expression of multiple CYP proteins and high levels of microsomal P450 in liver of fishes from Bermuda.

Hepatic microsomes prepared from 10 fish species from Bermuda were studied to establish features of cytochrome P450 (CYP) systems in tropical marine fish. The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 and 0.25 nmol/mg. Ethoxycoumarin O-deethylase (ECOD) and aminopyrine N-demethylase (APND) rates in these 7 species were 0.23-2.1 nmol/min/mg and 0.5-11 nmol/min/mg, respectively, similar to rates in many temperate fish species. In contrast to those 7 species, sergeant major (Abudefduf saxatilis) and Bermuda chub (Kyphosus sectatrix) had microsomal P450 contents near 1.7 nmol/mg, among the highest values reported in untreated fish, and had greater rates of ECOD, APND, ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-depentylase than did most of the other species. Freshly caught individuals of all species had detectable levels of EROD and aryl hydrocarbon hydroxylase (AHH) activities. Those individuals with higher rates of EROD activity had greater content of immunodetected CYP1A protein, consistent with Ah-receptor agonists acting to induce CYP1A in many fish in Bermuda waters. Injection of tomtate and blue-striped grunt with beta-naphthoflavone (BNF; 50 or 100 mg/kg) induced EROD rates by 25 to 55-fold, suggesting that environmental induction in some fish was slight compared with the capacity to respond. AHH rates were induced only 3-fold in these same fish. The basis for disparity in the degree of EROD and AHH induction is not known. Rates of APND and testosterone 6 beta- and 16 beta-hydroxylase were little changed by BNF, indicating that these are not CYP1A activities in these fish. Antibodies to phenobarbital-inducible rat CYP2B1 or to scup P450B, a putative CYP2B, detected one or more proteins in several species, suggesting that CYP2B-like proteins are highly expressed in some tropical fishes. Generally, species with greater amounts of total P450 had greater amounts of proteins related to CYP2B. These species also had appreciable amounts of CYP3A-like proteins. Thus, many fishes in Bermuda appear to have induced levels of CYP1A; some also have unusually high levels of total P450 and of CYP2B-like and CYP3A-like proteins. These species may be good models for examining the structural, functional and regulatory properties of teleost CYP and the environmental or ecological factors contributing to high levels of expression of CYP in some fishes.

Animals↗
PubMed1997

PU.1 functions in a cell-autonomous manner to control the differentiation of multipotential lymphoid-myeloid progenitors.

Transcription factor PU.1 is required for the development of lymphoid and myeloid progenitors during fetal hematopoiesis. By generating chimeric animals using PU.1-/- ES cells or PU.1(-/-) hematopoietic progenitors, we demonstrate that PU.1 functions in an exclusively cell-autonomous manner to regulate the development of the lymphoid-myeloid system. Multipotential lymphoid-myeloid progenitors (AA4.1+, Lin-) are significantly reduced in PU.1(-/-) embryos and fail to differentiate into B lymphoid or myeloid cells in vitro. These results suggest that the lymphoid and myeloid lineages develop in the fetal liver from a common hematopoietic progenitor not shared with erythrocytes and megakaryocytes. Finally, the Ikaros gene is expressed in PU.1 mutant embryos, suggesting that PU.1 and Ikaros are independently required for specification of embryonic lymphoid cell fates.

Animals↗
PubMed1997

Genetic studies on primary antibody response to sheep erythrocytes in guinea fowl.

1. The primary antibody response to sheep erythrocytes was determined by haemagglutination test in guinea fowl. The effects of various genetic and non-genetic factors on immune response to sheep RBCs in guinea fowl were also estimated. 2. The immune response to sheep RBCs was normally distributed in guinea fowl with mean titre at 1.534 +/- 0.014. 3. In guinea fowl, effects on titre values of sire and variety (feather colour) were significant whereas sex and sex x variety interaction effects were non-significant. 4. The estimate of heritability for immune response to sheep RBCs in guinea fowl was 0.35 +/- 0.17.

Animals↗
PubMed1997

Inheritance of wing feather development rate in guinea fowl (Numida meleagris).

1. A study of primary wing feather development rate in guinea fowl revealed genetic control through a single pair of sex-linked alleles. The allele for slow feathering (K) was dominant over that for rapid feathering (k+). 2. Wing feather sexing showed 94% accuracy in 10-d-old keets. 3. Incidence of rapid feathering allele (k+) was higher in the population selected for high body weight compared to the unselected population.

Alleles↗
PubMed1997

Electroencephalographic bispectral index correlates with intraoperative recall and depth of propofol-induced sedation.

The bispectral (BIS) index and 95% spectral edge frequency (SEF) of the electroencephalograph (EEG) have been used to study the anesthetic and sedative effects of intravenously (i.v.) administered drugs. This prospective study was designed to evaluate the effectiveness of the BIS index and 95% SEF for assessing the level of propofol-induced sedation and amnesia during regional anesthesia. Ten consenting adult patients undergoing surgery with regional anesthesia were administered propofol in increments of 10-20 mg i.v., every 5-10 min until they became unresponsive to tactile stimulation (i.e., mild prodding or shaking). The BIS index and 95% SEF were continuously recorded from a bifrontal montage (Fp1-Cz and Fp2-Cz) using the Aspect B500 monitor. The depth of sedation was assessed clinically at 5- to 10-min intervals using the observer's assessment of alertness/sedation (OAA/S) scale, with 1 = no response to tactile stimulation to 5 = wide awake. Each patient was shown a picture of an animal (cat) prior to administration of an initial dose of propofol, 40 mg i.v.. Subsequently, patients were administered intermittent bolus doses of propofol, 10-20 mg i.v., and shown different pictures upon achieving OAA/S scores of 4, 3, and 2 during the onset of and recovery from propofol-induced sedation. Picture recall was tested upon arrival of the patient in the postanesthesia care unit (PACU). Of the two EEG variables studied, the BIS index exhibited a better correlation with the OAA/S scores during both the onset (Spearman's rho = 0.744) and recovery (Spearman's rho = 0.705) phases of propofol-induced sedation. With the increasing depth of sedation, there was a progressive decrease in the BIS index (OAA/S score of 5, BIS = 94.5 +/- 2.9; 4, 93.3 +/- 3.3; 3, 89 +/- 6.1; 2, 80.1 +/- 8.7; 1, 75.6 +/- 7.5; mean +/- SD). Conversely, there was a progressive increase in the BIS value during recovery from propofol sedation (OAA/S score of 1, BIS = 75.6 +/- 7.5; 2, 82.4 +/- 10.5; 3, 84.9 +/- 5.9; 4, 93.8 +/- 0.8). Although the changes in the 95% SEF values were less consistent during the onset phase, this EEG variable increased from 16.4 +/- 5.0 to 19.3 +/- 5.6 as the OAA/S score increased from 1 to 4 during the recovery phase. Patient recall of the intraoperative pictures decreased with increasing depth of sedation and decreasing BIS values (OAA/S:% BIS:% recall = 5:94.5 +/- 2.9:100%; 4:93.4 +/- 3:63%; 3:87.3 +/- 6.1:40%; 2:80.8 +/- 8.3:0%; 1:75.6 +/- 7.5:0%). The BIS index appears to be a useful variable for assessing the depth of propofol-induced sedation. Increasing depth of sedation was associated with a significant decrease in intraoperative picture recall.

Adult↗
PubMed1997

Effects of ketorolac versus bupivacaine coadministration during patient-controlled hydromorphone epidural analgesia after thoracotomy procedures.

We studied the comparative effects of ketorolac versus bupivacaine supplementation of hydromorphone (HM) patient-controlled epidural analgesia (PCEA) on the HM requirement, postoperative pain, and pulmonary function in 62 consenting patients after thoracotomy procedures. Patients were randomly assigned to receive one of three different combinations of analgesic medications after the operation according to a double-blind, placebo-controlled study. The treatment groups consisted of: Group 1 (n = 23): PCEA HM 3-mL (0.15 mg) bolus doses + saline 1 mL intravenously (IV) q6h, Group 2 (n = 20): PCEA HM (0.15 mg) in 0.125% bupivacaine 3-mL bolus doses + saline 1 mL IV q6h, and Group 3 (n = 19): PCEA HM 3-mL (0.15 mg) bolus doses + ketorolac 1 mL (30 mg) IV q6h. Epidural HM and supplemental analgesic requirements, pain visual analog scale (VAS) scores, the incidence of nonincisional pain, and side effects were recorded at 24 and 48 h after surgery. Bedside pulmonary function tests were performed using a Puritan Bennett 100TM (Puritan-Bennett Corp., Wilmington, MA) spirometer before and 24 and 48 h after surgery. IV ketorolac supplementation of HM PCEA significantly reduced the incidence of nonincisional pain and the HM requirement over 48 h compared with the HM PCEA alone group (7% vs 26%; 3 +/- 1.6 mg vs 5.3 +/- 2.8 mg). Both ketorolac and bupivacaine supplementation of HM PCEA reduced the severity of pain on coughing and on movement compared with HM PCEA alone on postoperative day (POD) 1. Significant reductions in forced vital capacity, forced expiratory volume in 1 s, forced expiratory flow 25%-75% of the vital capacity, and peak expiratory flow rate (PEFR) were noted on PODs 1 and 2 in all three treatment groups. The decrease in PEFR on PODs 1 and 2 was significantly less with ketorolac compared with bupivacaine supplementation. We conclude that ketorolac supplementation of HM PCEA reduces the incidence of nonincisional pain and HM requirement compared with HM PCEA alone and may have a beneficial effect on pulmonary function compared with bupivacaine supplementation of HM PCEA in postthoracotomy patients.

Aged↗
PubMed1997

Optimal dose of nicardipine for maintenance of hemodynamic stability after tracheal intubation and skin incision.

UNLABELLED: To determine the optimal dose of nicardipine (N) for maintenance of hemodynamic stability during the postinduction period, we designed a randomized, double-blind, placebo-controlled, dose-ranging study using four different doses of N administered after a standardized anesthetic induction sequence. A total of 106 patients were assigned to one of the following treatment groups: saline (control), N 0.5 mg (N0.5), N 1 mg (N1), N 2 mg (N2), and N 4 mg (N4). The study medication was administered intravenously (I.V.) in 2.5 mL of saline over 30 s 2 min before laryngoscopy. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 1-min intervals for 15 min after tracheal intubation and for 5 min after skin incision. After intubation, the peak MAP values differed from the preinduction baseline MAP values by 21% +/- 20%, 9% +/- 12%, 1% +/- 13%, -10% +/- 12%, and -15% +/- 13% (mean +/- SD) in the control, N0.5, N1, N2, and N4 groups, respectively. However, the percent change in the pre- to postintubation MAP values (37% to 47%) was similar in all five groups. The highest postintubation HR values were recorded in the N4 group (P < 0.05 versus the other groups). However, the increases in MAP values after skin incision were the least in the N4 group. In conclusion, N1 I.V., administered 2 min before laryngoscopy provides optimal control of arterial blood pressure during the postinduction period. IMPLICATIONS: Acute increases in blood pressure during anesthesia are undesirable in patients with preexisting cardiovascular diseases. This double-blind study found that the calcium-channel blocker, nicardipine, 1 mg intravenously 2 min before tracheal intubation maintained hemodynamic stability during the intraoperative period.

Adult↗
PubMed1997

Chronic typhoid carriage and carcinoma of the gallbladder.

Chronic microbial infections and/or their carrier state have been reported to be associated with particular cancers. Since typhoid infections and carcinoma of the gallbladder (the site where salmonella usually persists) are endemic in northern India, it was considered important to explore the relationship between the two. In the present study, a total of 1001 bile specimens collected from cases of carcinoma of the gallbladder (28), cholelithiasis (56) and individuals without biliary pathology (17) were subjected to aerobic cultures that had been enriched for salmonella. Salmonella typhi and S. paratyphi-A could be detected in a significantly higher (P < 0.05) number in patients with carcinoma of the gallbladder as compared with cholelithiasis and control groups. The existence of such an association indicates that detection and eradication of typhoid carriers may lead to a decrease in the incidence of carcinoma of the gallbladder along with typhoid fever.

Bile↗
PubMed1997

Role of protein kinase C in beta 2-adrenoceptor function in cultured rat proximal tubule epithelial cells.

Renal sodium excretion is regulated by the adrenergic system. We recently demonstrated the presence of functional beta 2-adrenoceptors (beta 2-AR) in cultured rat proximal tubule epithelial cells beta 2-AR activation resulted in increases in Na-K-adenosinetriphosphatase (Na-K-ATPase) activity and transcellular sodium transport as a consequence of increased apical sodium entry. The purpose of this study was to determine the role of protein kinase C (PKC) on beta 2-AR-dependent increases in Na-K-ATPase activity and sodium transport in proximal tubules. To determine the effect of PKC on basal function, cultured rat proximal tubule cells were exposed to phorbol 12-myristate 13-acetate (PMA). PMA increased apical Na entry (+/-80%), decreased Na-K-ATPase activity (+/-25%), and prevented increases in Na-K-ATPase activity after sodium entry facilitation with monensin. Decreases in Na-K-ATPase activity were associated with decreases in sodium transport (+/-30%). To determine whether beta 2-AR function was transduced by PKC, PKC activity was measured in cells exposed to the selective beta 2-AR agonist metaproterenol. Metaproterenol caused increases in PKC activity, which were blocked by a beta 2-AR but not by a beta 1-AR-receptor antagonist. beta 2-AR-dependent increases in apical Na entry, Na-K-ATPase activity, and sodium transport were blocked by calphostin C or staurosporine. To determine whether PKC had additional effects on beta 2-AR function, cells were exposed to metaproterenol and PMA. Metaproterenol-induced increases in Na-K-ATPase activity and sodium transport were blocked by PMA. In conclusion, beta 2-AR-mediated increases in Na-K-ATPase activity and sodium flux are transduced by PKC acting through increases in apical Na entry. However, activation of PKC by phorbol esters inhibits beta 2-AR-dependent increases in Na-K-ATPase activity and sodium transport.

Adrenergic beta-Agonists↗
PubMed1997

The changing profile of Plasmodium falciparum malaria.

Resurgence of malaria has been noted in the Rohtak district (Haryana, India) after the recent floods. The profile of 66 patients of P. falciparum infection who were admitted to our hospital over one month in October 1995 is reported. While only a minority of cases (< 15%) presented with an uncomplicated course, all others developed one or more complication(s), some of them very rare. The usual manifestations viz, cerebral malaria, black water fever and algid malaria seen in the past were observed in less than half the patients. The remaining presented with unusual complications like haemolytic anaemia (46.2%), severe anaemia (37.9%), thrombocytopaenia (18.2%), pancytopaenia (6%), adult respiratory distress syndrome (4.5%) often not seen in sporadic cases of falciparum malaria which occurred in the past in this district. Similarly all deaths (15.1%) were noted in patients with rarer manifestations and only one patient died of cerebral malaria. This study confirms the occurrence of severe and complicated falciparum malaria in this part of the country.

Adult↗
PubMed1997

Isolation of Salmonella senftenberg bacteriophages.

A total of 61 bacteriophages were isolated from 100 strains of Salmonella senftenberg. Six bacteriophages were selected for typing purposes which were specific for S. senftenberg. Five phages, SasL1 to SasL5 were morphologically similar; phage SasL6 was morphologically different from the others. These phages fall into two morphological groups none of which correspond to the known tailed enterobacterial phage species. Hence, two new phage species represented by SasL1 and SasL6 are proposed.

Lysogeny↗
PubMed1997

Western blot analysis of serological response in Helicobacter pylori in acid peptic diseases.

A prospective study was undertaken in 70 patients presenting with acid peptic disease with the objective of characterising the serological response to Helicobacter pylori and finding antigens specific for the serodiagnosis of H. pylori infection. H. pylori status was assessed by smear microscopy, rapid urease activity, culture and histopathology of endoscopic gastric antral biopsy specimens. Serological characterisation was carried out by using western blotting of various antigenic components of H. pylori and subsequent enzymatic detection of antibodies against them. Four reactive bands in the molecular weight range of 45-65 kDa were present in all subjects irrespective of H. pylori status. Four to six immunoreactive bands in the molecular weight range of 21-45 kDa were found only in patients with positive H. pylori status and histopathologically proven gastritis. These immunoreactive components may be valuable in specific immunodiagnosis of H. pylori infection.

Adolescent↗
PubMed1997

Preparation and antibacterial evaluation of urinary balloon catheter.

Prolonged use of indwelling urinary catheters in bed-ridden patients lead to a variety of Urinary Tract Infections (UTI). The present study deals with the surface treatment of ready-made urinary catheters so as to render them antibacterial in nature. Catheters were treated with varying percentages of iodine in conjunction with natural rubber latex, and their iodide ion release pattern and antibacterial behaviour were evaluated.

Anti-Bacterial Agents↗
PubMed1996

Pip, a lymphoid-restricted IRF, contains a regulatory domain that is important for autoinhibition and ternary complex formation with the Ets factor PU.1.

Pip is a lymphoid-restricted IRF transcription factor that is recruited to composite elements within immunoglobulin light-chain gene enhancers through a specific interaction with the Ets factor PU.1. We have examined the transcriptional regulatory properties of Pip as well as the requirements for its interaction with PU.1 and DNA to form a ternary complex. We demonstrate that Pip is a dichotomous regulator; it specifically stimulates transcription in conjunction with PU.1, but represses alpha/beta-interferon-inducible transcription in the absence of PU.1. Thus, during B-cell activation and differentiation, Pip may function both as an activator to promote B cell-specific gene expression and as a repressor to inhibit the antiproliferative effects of alpha/beta-interferons. Mutational analysis of Pip reveals a carboxy-terminal segment that is important for autoinhibition of DNA binding and ternary complex formation. A domain of Pip containing this segment confers autoinhibition and PU.1-dependent binding activity to the DNA-binding domain of the related IRF family member, p48. On the basis of these and other data we propose a model for PU.1/Pip ternary complex formation.

Animals↗