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Biomedical subjects

S Singh

Publications and source records attributed to S Singh.

At least 271 records · Page 15Linked to original sources

Organochlorine pesticides in carcinoma of the gallbladder: a case-control study.

Carcinoma of the gallbladder is the third most common malignancy of the gastrointestinal tract in the Eastern Uttar Pradesh and Western Bihar regions of India. The main source of drinking water in this region is the river Ganges, which is heavily polluted with agricultural pesticides. Organochlorine pesticides were estimated in bile by gas liquid chromatography in 60 patients (30 carcinoma of the gallbladder and 30 cholelithiasis) to observe its association with aetiopathogenesis of carcinoma of the gallbladder. The mean biliary concentration of benzene hexachloride (BHC) was found to be significantly higher in carcinoma of the gallbladder (0.0471 ppm) than in cholelithiasis (0.0352 ppm) (P < 0.04). The mean biliary concentration of dichlorodiphenyltrichloroethane (DDT) was also significantly higher in carcinoma of the gallbladder (0.418 ppm) than in cholelithiasis (0.0103 ppm) (P < 0.03). Biliary aldrin and endosulfan concentrations were higher in carcinoma of the gallbladder (0.0008 and 0.00132 ppm) than in cholelithiasis (0.0005 and 0.0126 ppm) but the difference was statistically not significant (P < 0.06 and P < 0.9). The levels of pesticides in blood did not show significant differences in either carcinoma of the gallbladder or cholelithiasis. Significantly high biliary BHC and DDT concentrations suggest that these pesticides might be associated with gallbladder carcinogenesi.

Agriculture↗

A survey of nocturnal hypoxaemia and health related quality of life in patients with cryptogenic fibrosing alveolitis.

BACKGROUND: A survey of overnight oximetry was conducted to estimate the prevalence of nocturnal hypoxaemia in patients with cryptogenic fibrosing alveolitis and to establish whether nocturnal hypoxaemia is related to quality of life. METHODS: All patients with cryptogenic fibrosing alveolitis attending Nottingham City Hospital were invited to enter the study. Spirometric measurements and capillary blood gas tensions were obtained and overnight oxygen saturation was recorded at home. Quality of life was assessed using the Short Form-36, Chronic Respiratory Questionnaire, Hospital Anxiety Depression Scale, and Epworth Sleepiness Score questionnaires. RESULTS: Sixty seven eligible patients were identified and 50 agreed to enter the study, although two were subsequently excluded because they already used oxygen overnight. In the remaining 48 the mean (SD) overnight oxygen saturation (SaO(2)) was 92.5 (4.3)% and the median number of dips greater than 4% per hour was 2.3 (interquartile range 1.5-5.3). Daytime oxygen level predicted mean overnight SaO(2) (1.94%/kPa, 95% CI 1.22 to 2.66, p<0.001) but percentage predicted forced vital capacity (FVC) did not (0.018%/% predicted FVC, 95% CI -0.04 to 0.08, p=0.5). Nocturnal hypoxaemia was associated with decreased energy levels and impaired daytime social and physical functioning, and these effects were independent of FVC. CONCLUSIONS: Nocturnal hypoxaemia is common in patients with cryptogenic fibrosing alveolitis and may have an impact on health related quality of life.

Aged↗

Molecular and biochemical characterization of prostacyclin receptors in rat kidney.

The prostacyclin (IP) message was detected by RT-PCR in the renal cortex, outer (OM) and inner medulla (IM), and in freshly isolated (IMCD-f) and cultured inner medullary collecting duct (IMCD-c), and also the E-prostanoid (EP)1,3,4 receptor subtypes, but not EP2. Digoxigenin in situ hybridization localized IP mRNA in the tubules of the OM and IM, and the vasculature, and also in the glomeruli, arteries, and tubules of the cortex. IP splice variants or subtypes could not be detected by RT-PCR followed by TA cloning, though several nonfunctional point mutations or single base pair deletions were observed. Iloprost (ILP), cicaprost (CCP), PGE2, and arginine vasopressin (AVP) stimulated cAMP in both IMCD preparations. In addition, AVP-stimulated cAMP in IMCD-f was inhibited by all three prostanoids, but not in IMCD-c. Calcium experiments were performed on IMCD-c or microdissected IMCD (IMCD-m). CCP, ILP, and PGE2 did not alter intracellular calcium concentration ([Ca2+]i) in IMCD-c. However, on IMCD-m, both PGE2 and ILP increased [Ca2+]i levels equipotently and CCP had no effect. Pretreatment with the EP1 antagonist AH-6809 indicates that the response to ILP and PGE2 is mediated via EP1. These results suggest that IP receptors in the rat IMCD mediate the cAMP but not calcium signaling linked to PGI2; to date no subtypes or splice variants have been identified.

Animals↗

Intraoperative fibreoptic bronchoscopy during neonatal tracheo-oesophageal fistula ligation and oesophageal atresia repair.

Maintenance of adequate ventilation under anaesthesia can be difficult during identification and ligation of congenital tracheo-oesophageal fistula with repair of oesophageal atresia. Anaesthesia may also be complicated by problems associated with prematurity, pre-existing aspiration pneumonitis, and difficulty positioning the endotracheal tube to prevent inflation of the stomach with increased risk of aspiration and diaphragmatic splinting. Even intubation of the fistula and gastric rupture may occur. Two neonatal cases are presented where use of a 2.2 mm neonatal bronchoscope passed through a 3.0 mm ID tracheal tube facilitated surgical identification of the fistula, diagnosis of fistula intubation and other airway problems intraoperatively.

Bronchoscopes↗

Aggressive atropinisation and continuous pralidoxime (2-PAM) infusion in patients with severe organophosphate poisoning: experience of a northwest Indian hospital.

OBJECTIVE: The aim of the study was to find whether continuous pralidoxime (2-PAM) infusion along with aggressive atropinisation improves the outcome in patients with severe organophosphate poisoning who require assisted ventilation. METHODS: Sixteen patients admitted to the respiratory intensive care unit (RICU) with severe organophosphate poisoning and requiring assisted ventilation were included in the study. The compounds involved were phorate (six), dichlorvos (four), oxydimeton methyl (one), monocrotophos (one), methyl parathion (one) and in three it was unknown. After decontamination, they were given intravenous (iv) bolus atropine 5 mg at onset and then 2.5 mg every 5-10 min till atropinisation was achieved, and then maintained either by intermittent bolus doses or by continuous infusion if the required dose was large. They were also given continuous iv infusion of 2-PAM in dose of 7.5 mg/ kg body weight/h (maximum 500 mg/h) after an initial bolus dose of 2 g. RESULTS: The mean (+/-S.D.) dose of atropine was 735.02 +/- 742.98 mg (range 85-3000 mg) with maximum dose on day 1. The mean (+/-S.D) duration of 2-PAM infusion was 96.4+/-49.4 h (range 10-216 h). The mean (+/-S.D) duration of mechanical ventilation (MV) was 131.5 +/- 95.65 h (range 4-336 h). Fourteen patients could be successfully extubated and two died of bronchopneumonia and sepsis (mortality 12.5%). CONCLUSION: Continuous 2-PAM infusion along with aggressive atropinisation after initial decontamination improved the outcome but not the duration of MV in severely intoxicated patients with organophosphate compounds who required assisted ventilation in this case series.

Adolescent↗

Effects of duration and time of food availability on photoperiodic responses in the migratory male blackheaded bunting (Emberiza melanocephala).

The effects of the duration and time of food availability on stimulation of the photoperiodic responses (fattening and gain in body mass, and growth and development of testes) were investigated in the migratory blackheaded bunting (Emberiza melanocephala). Two experiments were performed. Experiment I examined the effects of a reduction in the duration of food supply in buntings that were subjected to long day lengths (16h:8h L:D) and received food ad libitum (group I) or for restricted durations, coinciding with the end of the lights-on period, of 8h (group II) and 4h (group III). Buntings of group I gained in body mass, whereas there was a mixed response in group II (half the birds gained and half lost body mass), and all birds of group III lost body mass. There was no effect on testis growth in groups I and II, but testes grew more slowly in group III. Experiment 2 investigated the effects of both the duration and the time of food availability. Of five groups of birds, group I was exposed to an 8h:16h L:D photoperiod, and groups II-V were exposed to 16h:8h L:D. Whereas birds of groups I and II received food ad libitum, those of groups III-V were fed only for 5 h, at zt 0-5 (group III), zt 5.5-10.5 (group IV) or zt 11-16 (group V), where zt = zeitgeber time and zt 0 refers to the beginning of the lights-on period. Apart from duration, the timing of food availability also had an effect on photoperiodic stimulation under the 16h:8h L:D photoperiod. Birds that were fed ad libitum fattened and gained in body mass, whereas among restricted feeding groups, only birds in the group fed during the first 5 h (zt 0-5, group III) showed a significant increase in body mass (albeit considerably lower than in the ad libitum group). Birds fed during the middle 5h (zt 5.5-10.5, group IV) showed an intermediate response, and those fed during the last 5h (zt 11-16, group V) lost body mass. Testicular growth was suppressed in birds that were fed for 5 h in the evening, but not in those fed for the same period in the morning or in the middle of the long day. Taken together, these results show that the duration of food supply and/or the time of day at which food is available affect photoperiodic stimulation of fattening and gain in body mass as well as the growth and development of gonads in the blackheaded bunting.

Animal Migration↗

Ethnic classification in primary dental care and dental health services research: time to pause for thought.

'Ethnicity' is an important concept in dental health services research and in enabling general dental practitioners to gain insight into their patients values and expectations. Since more health services research is being undertaken in primary dental care settings it is becoming an important issue for dental professionals and researchers in primary care to be aware of. Ethnicity is thought to be related to dental health inequalities and access and is often used as a stratifying variable in many dental studies. The meaning and use of the term however differs among researchers and among the public. It is clear that researchers and professionals need to pause for thought when considering what this often bandied about term actually means and the impact of different definitions. This is illustrated using examples from the authors' own research and published papers in the medical and dental literature. There is also much debate about whether ethnicity--however defined--is an important predictor of differences in dental health in itself or is merely a marker for other factors such as social deprivation or the impact of 'place' on dental health. While the jury on this debate is out we suggest guidelines on the reporting of ethnicity should be outlined in the dental literature--perhaps updating those published in 1996 in the British Medical Journal.

Cultural Characteristics↗

Epidemiology of breast cancer in older women: implications for future healthcare.

Breast cancer in elderly women is already a significant public health problem. Elderly women have a 6-fold higher breast cancer incidence rate and 8-fold higher mortality rate compared with non-elderly women. Because of demographic trends, the number of elderly women diagnosed with breast cancer is likely to increase substantially in the coming decades. Specifically, if incidence rates remain constant, we project a 72% increase in the number of elderly women in the US diagnosed with breast cancer by 2025, an increase from approximately 89,500 in 1998 to almost 154,000 in 2025. If this projection holds true, the sheer magnitude of the increase in patients has profound implications for the delivery of medical care. Considerable planning is needed to ensure that the infrastructure is in place to effectively treat these patients. The burgeoning number of elderly patients with breast cancer accentuates the need for more definitive evidence concerning preventing and treating breast cancer in the elderly. Treatment patterns for elderly patients with breast cancer have been shown to differ from those for non-elderly patients, but the evidence base for differentiating treatment plans by age is deficient. For example, information is needed to tease apart the relative importance of age per se compared with important age-related factors, such as comorbidity. Patient care will benefit from an interdisciplinary team approach that includes oncologists, geriatricians, surgeons, radiation oncologists, nurses and social workers. The continued increase in life expectancy necessitates well-crafted strategies for the primary and secondary prevention of breast cancer. Carefully addressing the priorities for breast cancer prevention and control in the elderly during the first portion of the century may reap substantial dividends by the end of the century.

Aged↗

A method to estimate urinary electrolyte excretion in patients at risk for developing cerebral salt wasting.

OBJECT: Two major criteria are necessary to diagnose cerebral salt wasting (CSW): a cerebral lesion and a large urinary excretion of Na+ and Cl- at a time when the extracellular fluid (ECF) volume is contracted. Nevertheless, it is difficult for the physician to confirm from bedside observation that a patient has a contracted ECF volume. Hyponatremia, although frequently present, should not be a criterion for a diagnosis of salt wasting. A contracted ECF volume is unlikely if there are positive balances of Na+ and Cl-. The goal of this study was to assess the accuracy of calculating balances for Na+ plus K+ and of Cl- over 1 to 10 days in an intensive care unit (ICU) setting. METHODS: A prospective comparison of measured and estimated quantities of Na+ plus K+ and of Cl- excreted over 1 to 10 days in 10 children and 12 adults who had recently received a traumatic brain injury or undergone recent neurosurgery. Plasma concentrations of electrolytes were recorded at the beginning and end of the study period. The total volumes infused and excreted and the concentrations of Na+, K+, and Cl- in the infusate were obtained from each patient's ICU chart. The electrolytes in the patients' urine were measured and calculated. Correlations between measured and calculated values for excretions of Cl- and of Na+ plus K+ were excellent. CONCLUSIONS: Mass balances for Na+ plus K+ and for Cl- can be accurately estimated. These data provide information to support or refute a clinical diagnosis of CSW. The danger of relying on balances for these electrolytes measured within a single day to diagnose CSW is illustrated.

Adolescent↗

Regional transcapillary albumin exchange in rodent endotoxaemia: effects of fluid resuscitation and inhibition of nitric oxide synthase.

Sepsis is characterized by increased microvascular permeability and regional variations in capillary perfusion, which may be modulated by nitric oxide (NO) and reversed by fluid resuscitation (FR). The effects of saline FR and NO synthase blockade [by N(G)-nitro-L-arginine methyl ester (L-NAME)] on microvascular albumin transport and perfused capillary density were assessed in anaesthetized Wistar rats with acute normodynamic endotoxaemia. Separate dual-isotope techniques were employed to measure the permeability index (PI(A)) and the permeabilityxsurface area product index (PI(B)), which provide different and complementary information regarding blood-tissue albumin exchange. PI(A) represents the tissue/blood distribution volume ratio of albumin. PI(B) is a composite measure of endothelial permeability and the vascular surface area available for albumin exchange, and therefore takes into account the effect of altered blood volume. Capillary density was quantified by fluorescence microscopy following circulation of Evans Blue-labelled albumin. Compared with controls, PI(A) was reduced significantly in lipopolysaccharide (LPS)-treated animals in skeletal muscle and skin, probably due to blood volume redistribution rather than to changes in permeability. PI(B) was increased significantly in LPS-treated animals in the kidney, mesentery, skeletal muscle, skin and lung, and in the small bowel following FR. FR also improved the LPS-induced metabolic base deficit, but did not alter capillary density. L-NAME significantly attenuated the LPS-induced rise in PI(B) in the lung. In conclusion, acute endotoxaemia induces tissue-dependent variations in microvascular albumin exchange. FR improves acid-base disturbance in endotoxaemia, through mechanisms other than microvascular recruitment. NO appears to increase microvascular permeability in endotoxaemia, an effect that may be attenuated by L-NAME, particularly in the lung.

Acute Disease↗

Benzimidazolone activators of chloride secretion: potential therapeutics for cystic fibrosis and chronic obstructive pulmonary disease.

The diseases of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are characterized by mucus-congested airways. Agents that stimulate the secretion of Cl- are anticipated to facilitate mucociliary clearance and thus be of benefit in the treatment of CF and COPD. Recently 1-EBIO (1-ethyl-2-benzimidazolinone or 1-ethyl-1,3-dihydro-2H-benzimidazol-2-one) was shown to stimulate chloride secretion albeit at relatively high concentrations (0.6-1 mM). The studies reported here were undertaken to develop a more potent benzimidazolone. Structure activity studies with 30 benzimidazolone derivatives revealed that ethyl and hydrogen groups at the 1 and 3 nitrogen positions, respectively, were critical for the activation of hIK1 K+ channels and that other alkyl groups were not tolerated at these positions without some loss in potency. Substitutions at the 5 and 6 positions improved the potency of 1-EBIO. Compared with 1-EBIO, the most potent of these derivatives, DCEBIO (5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one) was severalfold better in a 86Rb+ uptake assay, 20-fold better in short circuit current measurements on T84 monolayers, and 100-fold better in patch-clamp assays of hIK1 activity. Short circuit current studies revealed DCEBIO stimulates Cl- secretion via the activation of hIK1 K+ channels and the activation of an apical membrane Cl- conductance. The improved potency of DCEBIO strengthens the possibility that compounds in this class may be of therapeutic benefit in the treatment of CF and COPD.

Animals↗

Routine care of people with HIV infection and AIDS: should interested general practitioners take the lead?

People with HIV and AIDS in the developed world are living longer and healthier lives following the introduction of highly active antiretroviral therapy. The medical management of stable HIV infection could eventually fit into the more normal pattern of chronic disease management in the United Kingdom (UK). Routine monitoring of many chronic conditions is generally regarded as primary care business in partnership with secondary care. The latter service should be reserved for what it does best: periodic review, in-depth assessment, major changes in medication, management of complex or refractory cases, and inpatient care. We look at some of the issues and the arguments for and against any change from the current position in the UK, where almost all HIV infection is managed medically by specialist clinics in secondary and tertiary care.

Acquired Immunodeficiency Syndrome↗

Quality of Life Evaluation and Survival Study: a 3-yr prospective multinational study on patients with chronic respiratory failure.

Therapy of patients with chronic respiratory failure is mainly directed at minimizing symptoms in order to improve, or at least to prevent a deterioration of, patients' well-being. Under such circumstances, the perceived effect of therapies on patients' well-being and daily life represents the most important subjective outcome of treatment. Therefore, there is a need to provide a global estimate of health in patients on long term oxygen therapy or overnight home mechanical ventilation. The Maugeri Foundation Respiratory Failure Questionnaire (MRF28) is the first health status ("quality of life") questionnaire specifically developed for use in CRF and its items were selected to be applicable to patients with both obstructive and restrictive diseases. The Quality of Life Evaluation and Survival Study (QuESS) is a multinational study with the aim of re-evaluating the natural history of chronic respiratory failure in about 300 patients. To the authors knowledge, the Quality of Life Evaluation and Survival Study is the first study to evaluate the natural history of chronic respiratory failure in such a large number of subjects and with a complete set of data. In fact, both pathophysiologic and health status assessments will be made. Moreover, by collecting data on mortality, disease exacerbations and hospitalization, it will also be possible to verify the predictive ability of health status versus pathophysiology in terms of mortality and healthcare utilization.

Chronic Disease↗