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Biomedical subjects

S Mathur

Publications and source records attributed to S Mathur.

At least 19 recordsLinked to original sources
PubMed2006

Non-biopsy detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a prospective multicenter study.

BACKGROUND AND STUDY AIMS: There have been no multicenter studies investigating the use of magnification chromoendoscopy (MCE) for the detection of intestinal metaplasia and dysplasia/cancer in Barrett's esophagus. Our aims were to assess the ability of MCE to predict the histological diagnosis (non-biopsy detection), to compare the yield of MCE-targeted versus random biopsies for dysplasia, and to compare procedure times. PATIENTS AND METHODS: In this prospective multicenter study, patients with known or suspected Barrett's esophagus underwent MCE with indigo carmine dye staining. Three mucosal patterns (ridge/villous, circular, and irregular/distorted) were standardized, based on past experience. Mucosal patterns were noted and target biopsies were obtained only if irregular/distorted patterns were identified. Otherwise, random four-quadrant biopsies were obtained. RESULTS: A total of 56 patients (mean age 64 years, mean length of Barrett's esophagus 2.7cm) were prospectively evaluated: 38 patients (67.8 %) had ridge/villous patterns, four patients (7.1 %) had circular patterns, four patients (7.1 %) had irregular/distorted patterns, and ten patients (17.8 %) had a combination of patterns. Histologically, intestinal metaplasia was not shown in eight patients (14.2 %), nondysplastic Barrett's esophagus was diagnosed in 30 patients (53.5 %), low-grade dysplasia was detected in 12 patients (21.4 %), and high-grade dysplasia was detected in six patients (10.7 %). An irregular/distorted pattern either throughout the entire segment of Barrett's esophagus or in combination with a ridge/villous or circular pattern had a sensitivity or 83 %, a specificity of 88 %, a positive predictive value of 45 %, and a negative predictive value of 98 % for high-grade dysplasia. The yield of high-grade dysplasia was similar for the two techniques but the time taken to perform MCE was less than the time taken to perform random biopsies. CONCLUSION: An irregular/distorted pattern is specific for high-grade dysplasia and so it may not be necessary to perform biopsies in patients with ridge/villous or circular mucosal patterns.

Adult↗
PubMed2006

Effects of oestrogen on trigeminal ganglia in culture: implications for hormonal effects on migraine.

Although migraine is more common in women than men and often linked to the menstrual cycle, few studies have investigated the biological basis of hormonal influences on the trigeminovascular system. In the present study we investigated the effect of physiological levels (10(-9) m) oestrogen on female rat trigeminal ganglia in vitro. Immunocytochemical analysis demonstrated the presence of oestrogen receptor-alpha in a predominantly cytoplasmic location and in neurites. Microarray analysis demonstrated that oestrogen treatment regulates several genes with potential relevance to menstrual migraine. The genes that were upregulated included synapsin-2, endothelin receptor type B, activity and neurotransmitter-induced early gene 7 (ania-7), phosphoserine aminotransferase, MHC-1b, and ERK-1. Down-regulated genes included IL-R1, bradykinin B2 receptor, N-tropomodulin, CCL20, GABA transporter protein, fetal intestinal lactase-phlorizin hydrolase, carcinoembryonic antigen-related protein, zinc finger protein 36, epsin 1 and cysteine string protein. Protein activity assays demonstrated that exposure of the cultured neurons to oestrogen leads to activation of ERK, which has been linked to inflammatory pain. Immunocytochemistry demonstrated that activated ERK was present in neurons containing peripherin, a marker of nociceptive neurons. Several of the genes in the present study may provide potential targets for understanding the association of oestrogen with migraine and other hormone-related orofacial pain.

Animals↗
PubMed2006

A randomised controlled trial of ablation of Barrett's oesophagus with multipolar electrocoagulation versus argon plasma coagulation in combination with acid suppression: long term results.

BACKGROUND: Many modalities have been used to ablate Barrett's oesophagus (BO). However, long term results and comparative effectiveness are unknown. AIMS: Our aim was to compare the long term efficacy of achieving complete reversal (endoscopic and histological) between multipolar electrocoagulation (MPEC) and argon plasma coagulation (APC) in BO patients and assess factors influencing successful ablation. METHODS: Patients with BO, 2-6 cm long, underwent 24 hour pH testing on proton pump inhibitor (PPI) therapy. Patients were then randomised by BO length to undergo ablation with MPEC or APC every 4-8 weeks until endoscopic reversal or maximal of six treatment sessions. RESULTS: Thirty five BO patients have been followed for at least two years following endoscopic ablation, 16 treated with MPEC and 19 with APC. There was complete reversal of BO in 24 patients (69%); 75% with MPEC and 63% with APC (p = 0.49). There was no difference in the number of sessions required in the two groups. There was no difference in age, pH results, BO length, PPI dose, or hiatal hernia size between patients with and without complete reversal. One patient developed an oesophageal stricture but there were no major complications such as bleeding or perforation. CONCLUSIONS: In BO patients treated with MPEC or APC in combination with acid suppression, at long term follow up, complete reversal of BO can be maintained in approximately 70% of patients, irrespective of the technique. There are no predictors associated with achieving complete reversal of BO. Continued surveillance is still indicated in the post ablative setting. As yet, these techniques are not ready for clinical application (other than for high grade dysplasia or early oesophageal adenocarcinoma) and cannot be offered outside the research arena.

Adult↗
PubMed2005

Lack of predictors of normalization of oesophageal acid exposure in Barrett's oesophagus.

BACKGROUND: Barrett's oesophagus patients may continue to have abnormal oesophageal acid exposure on proton pump inhibitor therapy. The effect of factors such as Barrett's oesophagus length, hiatal hernia size and Helicobacter pylori infection on intra-oesophageal pH in Barrett's oesophagus patients has not been adequately studied. AIM: To evaluate oesophageal acid exposure in a large Barrett's oesophagus population on b.d. proton pump inhibitor therapy and determine clinical factors predicting normalization of intra-oesophageal pH on therapy. METHODS: Barrett's oesophagus patients were studied using 24 h pH monitoring to evaluate intra-oesophageal acid suppression on b.d. dosing of rabeprazole. RESULTS: Forty-six Barrett's oesophagus patients completed the study. Median total percentage time pH < 4 was 1.05% (range: 0-29.9%) in the entire group and respective values for upright and supine percentage time pH < 4 were 1.15% and 0%. However, 34 of the Barrett's oesophagus patients (73.9%) had a normal pH study (median total percentage time pH < 4: 0.2%) and 12 patients (26.1%) had an abnormal result (median total percentage time pH < 4: 9.3%). There were no significant differences between patients with a normal and abnormal 24 h pH result with respect to age, Barrett's oesophagus length, hiatal hernia size and presence of H. pylori infection. CONCLUSIONS: Approximately 25% of Barrett's oesophagus patients continue to have abnormal total intra-oesophageal pH profiles despite b.d. proton pump inhibitor therapy. Factors such as age, Barrett's oesophagus length and hiatal hernia size cannot be used to predict persistent abnormal intra-oesophageal pH on proton pump inhibitor.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2005

Factors modulating the pH at which calcium and magnesium phosphates precipitate from human urine.

The factors controlling the rate at which crystalline bacterial biofilms develop on indwelling bladder catheters are poorly understood. It is known that normally the pH of voided urine (pHv) is lower than the pH at which calcium and magnesium phosphates come out of urine solution (pHn). In patients who develop infections with urease producing bacteria, however, the pHv rises above the pHn and precipitation of the phosphates occurs in the urine and the biofilm. The aim of this study was to examine ways of manipulating the pHn of urine so that more of its calcium and magnesium remain in solution under alkaline conditions. The experimental data show that pHn can be elevated by decreasing the calcium, magnesium and phosphate concentrations. Increasing the fluid intake of a human subject so that the urinary calcium fell from 120 mg/l to 25 mg/l, for example, resulted in the pHn increasing from 6.48 to 8.22. The addition of citrate to urine also produced a rise in the pHn. The daily consumption of 500 ml of fresh orange juice increased urinary citrate concentrations from 0.35 to around 1.21 mg/ml and the pHn rose from 7.24 to 8.2. The pHn of urine is thus a highly variable parameter. It can be manipulated by controlling the urinary concentrations of magnesium, calcium, phosphate and citrate ions. We suggest that increasing fluid intake with citrate containing drinks would reduce the extent of encrustation on catheters in patients infected with urease producing bacteria.

Adult↗
PubMed2005

Reliability of surface EMG during sustained contractions of the quadriceps.

The purpose of this study was to determine test-retest reliability for median frequency (MDF) and amplitude of surface EMG during sustained fatiguing contractions of the quadriceps. Twenty-two healthy subjects (11 males and 11 females) were tested on two days held one week apart. Surface EMG was recorded from rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM) during sustained isometric contractions at 80% and 20% of maximal voluntary contraction (MVC) held to exhaustion. Quadriceps fatigue was described using four measures for both MDF and amplitude of EMG: initial, final, normalized final and slope. For both MDF and amplitude, the initial, final and normalized EMG showed moderate to high reliability for all three muscle groups at both contraction levels (ICC=0.59-0.88 for MDF; ICC=0.58-0.99 for amplitude). Slope of MDF and amplitude was associated with a large degree of variability and low ICCs for the 80% but not the 20% MVC. MDF and amplitude of EMG during sustained contractions of the quadriceps are reproducible; normalized final values of MDF and amplitude show better reliability than slope.

Adult↗
PubMed2005

Hypertensive encephalopathy in cats with reduced renal function.

The clinical, hemodynamic, and pathologic features of hypertensive encephalopathy in two cats with reduced renal mass are described. The cats developed a progressive syndrome of lethargy, ataxia, blindness, stupor, and seizures following an abrupt increase in blood pressure associated with a surgical reduction in renal mass. The cats had severe gross brain edema, evidenced by cerebellar changes of caudal coning and cranial displacement over the corpora quadrigemina and cerebral changes of widening and flattening of the gyri. Histologically, interstitial edema was most pronounced in the cerebral white matter. Hypertensive vascular lesions were present as hyaline arteriolosclerosis in one cat and hyperplastic arteriolosclerosis in the other. Rare foci of parenchymal microhemorrhages and necrosis were also observed. Systemic hypertension (especially severe or rapidly developing) accompanied by neurologic signs and the pathologic findings of diffuse brain edema with cerebral arteriolosclerosis are consistent with an etiologic diagnosis of hypertensive encephalopathy.

Animals↗
PubMed2005

Extreme hypervascularity and bruit in a treated hypothyroid goitre.

A child in early puberty, who presented with a modestly enlarged thyroid gland and confirmed hypothyroidism, was successfully treated with thyroxine. Subsequently a widespread bruit developed in the neck caused by bilaterally dilated superior thyroid arteries with increased blood flow to the goitre. At thyroidectomy, histopathology showed features of dyshormonogenesis with greatly increased vascularity and widespread diffuse staining for vascular endothelial growth factor (VEGF). It is likely that VEGF in association with other angiogenetic factors was associated with enlargement of the gland and its hypervascularity.

Child↗
PubMed2004

The treatment of skin carcinoma, induced by UV B radiation, using 1-oxo-5beta, 6beta-epoxy-witha-2-enolide, isolated from the roots of Withania somnifera, in a rat model.

Histopathological studies of the cutaneous tissues of Wistar rats exposed to UV B radiation (294 nm) for 20 days and rats exposed to UV B radiation for 20 days, followed by topical treatment with benzoyl peroxide, a tumor promoter (20 mg/animal/0.2 ml acetone) twice a week for 1 month, and kept under observation for 12 weeks, demonstrate the development of malignancy. Pretreatment of the animals with 1-oxo-5beta, 6beta-epoxy-witha-2-enolide (20 mg/kg bwt.), isolated from the roots of Withania somnifera, prior to exposing the animals to UV B radiation, prevents the incidence of skin carcinoma. The administration of 1-oxo-5beta, 6beta-epoxy-witha-2-enolide, to the animals after exposing them to UV B radiation/UV B radiation and benzoyl peroxide also prevents the occurrence of malignancy in the cutaneous tissue. Immunohistochemical staining of the cutaneous tissues of rats exposed to UV B radiation show the presence of p53 + foci (clusters of cells containing the mutated p53 protein), whereas an absence of p53 + foci is observed in animals pretreated with 1-oxo-5beta, 6beta-epoxy-witha-2-enolide. These results prove that 1-oxo-5beta, 6beta-epoxy-witha-2-enolide has the potential for acting as an effective agent to prevent the incidence of skin carcinoma induced by UV B radiation.

Animals↗
PubMed2003

Influence of hydraulic shock loads and TDS on the performance of large-scale CETPs treating textile effluents in India.

The present study relates to the influence of hydraulic shock loads and total dissolved solids (TDS) on the performance of three large-scale common effluent treatment plants (CETPs) treating textile effluents, which is generated from clusters of small-scale industries in the state of Rajasthan in India. Of the three CETPs, two having capacities 7.0 and 9.0 million liters per day (mld) are located in Pali and one of capacity 6.0 mld in Balotra, District Barmer. Wastewater from about one thousand small-scale industries is treated in these CETPs. The effects of hydraulic shock loads and TDS on effluent data from secondary clarifier for parameters biochemical oxygen demand (BOD) and suspended solids (SS) for CETPs at Pali, and chemical oxygen demand (COD) and SS for the CETP at Balotra were studied. It was observed that the effluent BOD and SS remained within the prescribed limits for CETP Pali at 30% increased flow rate, whereas effluent COD and SS at 30% increased flow rate for CETP Balotra exceeded the prescribed limits and the CETP could sustain 20% increased flow rate. The shock loading analysis revealed that CETP Balotra had reduced capacity to sustain shock loads by 10% as compared to CETP Pali due to the presence of high TDS (15,000-20,000 mg/l). High TDS interfered with the oxygen transfer necessary for biological metabolism, thereby affected the efficiency of activated sludge process. Hence, activated sludge process treating high TDS effluents are more sensitive to hydraulic shock loads and prone to process upsets.

India↗
PubMed2002

Molecular analysis of two complete rice tungro bacilliform virus genomic sequences from India.

The complete genomic sequences of two geographically distinct isolates of rice tungro bacilliform virus (RTBV) from India were determined. Both the sequences showed equal divergence from previously reported Southeast Asian isolates. Numerous insertions, deletions and substitutions, mostly in the intergenic regions, were found. The genome sizes were 7907 and 7934 bp respectively, 95 and 68 residues short of an infectious clone reported earlier. Between them, both the isolates showed high homology all along the genome, except for a 30-nucleotide insertion/deletion close to the 3' end of ORF III in one of them. Both the isolates indicated an unconventional start codon in ORF I, similar to the type isolate. In addition, as novel features, both the Indian isolates showed an unconventional start codon for ORF IV. Considering the low amounts of genome variability noticed in other RTBV isolates, the Indian isolates show that they have diverged sufficiently from the rest and should be considered belonging to a distinct strain.

Amino Acid Sequence↗
PubMed2002

Biological control of stem canker of greenhouse tomatoes caused by Botrytis cinereal.

Experiments were conducted to study the effect of various chemical and biological agents on stem canker caused by Botrytis cinerea Pers.: Fr. on tomato plants grown in sawdust under near-commercial greenhouse conditions. Lesion lengths following treatment with RootShield and strain S33 of Rhodosporidium diobovatum Newell & Hunter, applied as post-inoculation sprays, were significantly smaller than those in inoculated controls. These treatments also increased fruit yield and decreased the number of dead plants compared with inoculated controls. Decree, Prestop, and R. diobovatum S33, applied as sprays, prevented the occurrence of stem canker and increased fruit yield in tomato. The number of dead plants was also smaller with these treatments than with the other treatments and in inoculated controls. These results suggest that, in tomato, post-inoculation sprays of RootShield and R. diobovatum S33 can reduce lesion lengths, and that a preventive spray of Decree, Prestop, and R. diobovatum S33 might prevent stem canker, under near-commercial greenhouse conditions.

Botrytis↗
PubMed2001

Stereotactic radiosurgery in New Zealand.

AIMS: To explain the use of Stereotactic Radiosurgery for intracranial lesions and report Dunedin Hospital's early experience with this treatment. METHODS: Review of a prospective computer database and departmental clinical files. RESULTS: 74 patients underwent 78 radiosurgical procedures between 30 July 1994 to 18 December 1997. 28 patients with arteriovenous malformations were treated with an obliteration rate of 82% (95% CI: 48% to 98%) at two years. Seventeen vestibular schwannomas (acoustic neuroma's) were treated, with follow-up magnetic resonance imaging available in eleven in whom there was no tumour progression after a mean period of twelve months. There was preservation of some hearing in all patients not already deaf, but one developed a new facial palsy and another had worsening palsy as late side effects. Other tumours, including selected metastases, gliomas and skull base tumours have been treated in smaller numbers. CONCLUSION: Rates of arteriovenous malformation obliteration, vestibular schwannoma control, and side effects of radiosurgery in Dunedin are comparable to those reported in other uncontrolled series. Radiosurgery is quick and has a low procedure-related morbidity but does have important limitations and delayed side effects, which means the decision to treat needs to be based on thorough multidisciplinary review.

Adolescent↗
PubMed2001

Adolescent girls' life aspirations and reproductive health in Nepal.

The study described in this paper takes a participatory and positive approach to improving adolescent reproductive health in a rural and urban community in Nepal. It shows that adolescent girls in these communities have dreams and aspirations for a better future and that adults acknowledge and support these ideals. However, social norms and institutions are restrictive, especially for girls, who are often unable to realise their hopes for continuing education, finding better-paid work or delaying marriage and childbearing, and this directly impacts reproductive outcomes. Insight into the broader context of adolescent girls' lives provides a valuable framework for designing positive programmatic actions which take as their entry point the disjuncture between girls' aspirations and realities. Interventions begun in these communities include youth clubs for safe social interaction and literacy classes; training of peer educators to teach life-skills, including for married adolescents; forums for parents, teachers and health service providers to discuss their own concerns and those of adolescents; and work with the community to design programmes that will contribute to greater financial independence and employment opportunities for adolescents.

Adolescent↗
PubMed2001

Fumonisin B(1) increases serum sphinganine concentration but does not alter serum sphingosine concentration or induce cardiovascular changes in milk-fed calves.

Fumonisin B(1) is the most toxic and commonly occurring form of a group of mycotoxins that alter sphingolipid biosynthesis and induce leukoencephalomalacia in horses and pulmonary edema in pigs. Purified fumonisin B(1) (1 mg/kg, iv, daily) increased serum sphinganine and sphingosine concentrations and decreased cardiovascular function in pigs within 5 days. We therefore examined whether the same dosage schedule of fumonisin B(1) produced a similar effect in calves. Ten milk-fed male Holstein calves were instrumented to obtain blood and cardiovascular measurements. Treated calves (n = 5) were administered purified fumonisin B(1) at 1 mg/kg, iv, daily for 7 days and controls (n = 5) were administered 10 ml 0.9% NaCl, iv, daily. Each calf was euthanized on day 7. In treated calves, serum sphinganine concentration increased from day 3 onward (day 7, 0.237 +/- 0.388 micromol/l; baseline, 0.010 +/- 0.007 micromol/l; mean +/- SD), whereas, serum sphingosine concentration was unchanged (day 7, 0.044 +/- 0.065 micromol/l; baseline, 0.021 +/- 0.025 micromol/l). Heart rate, cardiac output, stroke volume, mean arterial pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, central venous pressure, plasma volume, base-apex electrocardiogram, arterial Po(2), and systemic oxygen delivery were unchanged in treated and control calves. Fumonisin-treated calves developed metabolic acidosis (arterial blood pH, 7.27 +/- 0.11; base excess, -9.1 +/- 7.6 mEq/l), but all survived for 7 days. We conclude that calves are more resistant to fumonisin B(1) cardiovascular toxicity than pigs.

Acidosis, Respiratory↗