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Biomedical subjects

S Rao

Publications and source records attributed to S Rao.

At least 127 records · Page 7Linked to original sources
PubMed2000

Expansion of Chiari I-associated syringomyelia after posterior-fossa decompression.

UNLABELLED: Chiari I malformation (CMI) is an abnormality that involves caudal herniation of the cerebellar tonsils into the foramen magnum. CMI has been shown to be closely associated with the development of syringomyelia (SM). OBJECTS: Several theories have emerged to explain the apparent correlation between the existence of CMI with subsequent development of SM. However, the exact mechanism of the evolution of SM is still subject to controversy. We report here the case of a 12-year-old girl admitted to hospital with headache, vomiting, ataxia, and moderate pyramidal signs. METHODS: Radiological evaluation revealed the presence of CMI, accompanied by a small SM. The patient underwent posterior fossa decompression and improved significantly. She was re-admitted 6 months later with clinical evidence of progressive spinal cord dysfunction. MR revealed gross expansion of the syrinx. CONCLUSIONS: This case raises questions regarding the pathophysiology of CMI and its association with SM. The case indicates the need for neurological and radiological follow-up for patients undergoing posterior fossa decompression due to CMI, even for those without an initial syrinx. This is the first report known to us of expansion of a syrinx following decompression of an associated CMI.

Arnold-Chiari Malformation↗
PubMed2000

Modification of alpha subunit of RIIA sodium channels by aconitine.

The effect of aconitine (AC), an alkaloid toxin, on the electrophysiological properties of the rat brain type IIA alpha subunit expressed heterologously in the Chinese Hamster Ovarian (CHO) cell line was studied under the whole-cell patch-clamp configuration. The activation threshold of modified channels shifted by about -40 mV. As the number of depolarizations increased, the transient current at 0 mV decreased and, in proportion, the AC-modified current at -50 mV increased. This suggests a transition of channels to an AC-modified state. The rate of modification was nearly four times faster when 50 microM AC was applied internally than when applied in the bath solution. This supports the idea that the AC-binding site is located close to the cytoplasmic mouth of the channel pore. The AC-modified sodium currents inactivated completely, although with slower kinetics. The steady-state inactivation followed a simple Boltzmann function. AC-modified currents activated without a sigmoidal delay. The permeability of the NH4+ ion was enhanced such that its permeability ratio increased from an initial value of 0. 18 to 0.95 and for Cs+ it was enhanced from 0.03 to 0.07. These studies show that the AC-binding site resides at the pore region of the alpha subunit of the Na+ channel, and that the presence of beta subunit/s is not essential for AC binding.

Aconitine↗
PubMed2000

Role of antioxidant enzymes in brain tumours.

Erythrocyte antioxidant enzymes were analysed in 100 patients with intracranial neoplasm and in 47 controls. There was a significant decrease in RBC glutathione reductase (GRx) and superoxide dismutase (SOD) activity in most types of brain tumor cases. Patients with acoustic neurinoma showed a significant reduction in selenium-dependent glutathione peroxidase (Se-GPx) activity. A decrease in catalase (CT) activity was seen in most of the brain tumor patients but remained statistically insignificant when compared to controls. A significant increase in plasma ceruloplasmin concentration was observed in patients with glioma. These enzymes were also studied in 27 post-treatment cases. GRx activity returned to normal levels in these patients. RBC SOD and plasma ceruloplasmin levels showed a tendency to return to normal. Hence, a marked decrease in the antioxidant enzymes may have a role in the genesis of considerable oxidative stress in patients with brain tumors.

Adolescent↗
PubMed2000

Development of subscales from the symptoms/problems and effects of kidney disease scales of the kidney disease quality of life instrument.

BACKGROUND: The Kidney Disease Quality of Life Instrument (KDQOL) was developed to provide clinicians with a comprehensive assessment of the important domains of health-related quality of life (HRQOL) for patients with end-stage renal disease who are undergoing hemodialysis. OBJECTIVE: The purpose of this study was to develop subscales from the 55 items comprising the Symptoms/Problems and Effects of Kidney Disease scales of the KDQOL and to measure the internal consistency reliability of these subscales. METHODS: The 55 items from the Symptoms/Problems and Effects of Kidney Disease scales were arranged into substantively meaningful clusters using an affinity mapping procedure. The resulting subscales were assessed for internal consistency reliability using data from a sample of 165 individuals with kidney disease who had completed the KDQOL. RESULTS: Eleven multi-item subscales were identified: pain, psychological dependency, cognitive functioning, social functioning, dialysis-related symptoms, cardiopulmonary symptoms, sleep, energy, cramps, diet, and appetite. Four items (clotting or other problems with access site, high blood pressure, numbness in hands or feet, and blurred vision) were not included in any of these subscales. Internal consistency reliability estimates for the 11 subscales ranged from 0.66 to 0.92. These subscales correlated with the scales from the 36-Item Short-Form Health Survey as hypothesized (ie, corresponding pain, energy, and social functioning scales had the highest correlations). In addition, several subscales were significantly associated, as hypothesized, with other variables such as the number of disability days. CONCLUSIONS: The results of this study further support the reliability and validity of the KDQOL. The 11 subscales identified yield more detailed information on the HRQOL of patients with kidney disease and provide a basis for specific improvements in the quality of care delivered to these patients.

Adult↗
PubMed2000

Effect of laser in situ keratomileusis on tear stability.

OBJECTIVE: Patients frequently experience dry eye symptoms after laser in situ keratomileusis (LASIK). The mechanisms that lead to these changes are not well understood. The purpose of this study was to investigate the effect of LASIK on tear function. DESIGN: Prospective, comparative, nonrandomized interventional trial. PARTICIPANTS: Fifty-eight consecutive patients (96 eyes) who underwent myopic LASIK treatment. METHODS: The prospective study involved 58 consecutive patients (96 eyes) who underwent sequential or bilateral LASIK for the correction of myopia. Dry eye symptoms, standardized Schirmer test values, basal tear secretion test, and tear break-up time were measured before surgery and 1 day, 1 week, and 1 month after surgery. MAIN OUTCOME MEASURES: Schirmer test value, basal tear secretion value, and tear break-up time. RESULTS: Before surgery, 15.6% of patients (15/96) had dry eye symptoms. After surgery, 94.8% of patients (91/96), 85.4% of patients (82/96), and 59.4% of patients (57/96) experienced dry eye symptoms at 1 day, 1 week, and 1 month, respectively. Schirmer test value (13.32 +/- 10. 67 mm) increased at 1 day (14.48 +/- 10.57 mm; P = 0.25) and subsequently decreased at 1 week (11.18 +/- 9.81 mm; P = 0.05) and at 1 month (10.83 +/- 10.02 mm; P = 0.03). Basal tear secretion test value (8.49 +/- 8.48 mm) decreased at 1 day (6.80 +/- 6.48 mm; P = 0.05), at 1 week (5.97 +/- 6.88 mm; P = 0.005), and at 1 month (5.89 +/- 6.24 mm; P = 0.007). Tear break-up time (5.32 +/- 2.35 seconds) decreased 1 day (4.14 +/- 1.90 seconds; P < 0.001) and 1 week (4.49 +/- 1.70 seconds; P = 0.004) after surgery and recovered by 1 month after surgery (5.09 +/- 3.03 seconds; P = 0.52). Poor preoperative tear functions with a Schirmer test value less than 10 mm was a significant risk factor (72% vs. 46%; relative risk, 1.58 [1.10-2.26]) for experiencing dry eye symptoms at 1 month after surgery. CONCLUSIONS: Dry eye symptoms are common after myopic LASIK surgery. Laser in situ keratomileusis significantly altered the tear break-up time, Schirmer test values, and basal tear secretion. Patients with preexisting tear flow abnormality as demonstrated by Schirmer test values less than 10 mm are especially at risk of experiencing dry eye symptoms.

Adult↗
PubMed2000

Strategies for genetic mapping of categorical traits.

The search for efficient and powerful statistical methods and optimal mapping strategies for categorical traits under various experimental designs continues to be one of the main tasks in genetic mapping studies. Methodologies for genetic mapping of categorical traits can generally be classified into two groups, linear and non-linear models. We develop a method based on a threshold model, termed mixture threshold model to handle ordinal (or binary) data from multiple families. Monte Carlo simulations are done to compare its statistical efficiencies and properties of the proposed non-linear model with a linear model for genetic mapping of categorical traits using multiple families. The mixture threshold model has notably higher statistical power than linear models. There may be an optimal sampling strategy (family size vs number of families) in which genetic mapping reaches its maximal power and minimal estimation errors. A single large-sibship family does not necessarily produce the maximal power for detection of quantitative trait loci (QTL) due to genetic sampling of QTL alleles. The QTL allelic model has a marked impact on efficiency of genetic mapping of categorical traits in terms of statistical power and QTL parameter estimation. Compared with a fixed number of QTL alleles (two or four), the model with an infinite number of QTL alleles and normally distributed allelic effects results in loss of statistical power. The results imply that inbred designs (e.g. F2 or four-way crosses) with a few QTL alleles segregating or reducing number of QTL alleles (e.g. by selection) in outbred populations are desirable in genetic mapping of categorical traits using data from multiple families.

Alleles↗
PubMed2000

Phase I study of irinotecan and raltitrexed in patients with advanced gastrointestinal tract adenocarcinoma.

To determine the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of irinotecan and raltitrexed given as sequential short infusions every 3 weeks, 33 patients with pretreated gastrointestinal adenocarcinoma (31 colorectal, 2 oesophagogastric) entered this open label dose-escalation study. For the first five dose levels patients received irinotecan 175-350 mg m(-2) followed by raltitrexed 2.6 mg m(-2). Level VI was irinotecan 350 mg m(-2) plus raltitrexed 3.0 mg m(-2), level VII was irinotecan 400 mg m(-2) plus raltitrexed 2.6 mg m(-2); 261 courses were administered. Only one patient at dose levels I-V experienced DLT. At level VI, 5/12 patients experienced DLT: one had grade 3 diarrhoea and lethargy, one had grade 4 diarrhoea and one had lethargy alone. Two others had lethargy caused by disease progression. There was no first-cycle neutropenia. At level VII, 3/6 patients experienced dose-limiting lethargy, one also had grade 3 diarrhoea. Dose intensity fell from over 90% for both drugs at level VI to 83% for irinotecan and 66% for raltitrexed at level VII. Lethargy was therefore the DLT, and level VII the MTD. Pharmacokinetic data showed no measurable drug interaction; 6/30 patients (20%) had objective responses. This combination is active with manageable toxicity. Recommended doses for further evaluation are irinotecan 350 mg m(-2) and raltitrexed 3.0 mg m(-2).

Adenocarcinoma↗
PubMed2000

Primary gastrointestinal sarcomas: analysis of prognostic factors and results of surgical management.

BACKGROUND: This study was done to review the clinical presentation, surgical management, and prognostic factors for primary gastrointestinal sarcomas. METHODS: We reviewed medical records of 55 patients who were treated for primary gastrointestinal sarcomas from 1981 through 1996. Mean follow-up time was 32 months. RESULTS: Clinical findings included gastrointestinal bleeding (51%), palpable mass (36%), and abdominal pain (33%). The stomach was the most common site of disease (53%), followed by the small intestine (33%). Tumors were high grade in 76% of patients and low-grade in 24% of patients. Complete resection of all gross disease was accomplished in 35 patients (64%), incomplete resection in 17 patients (31%), and biopsy only in 3 patients (5%). Adjacent organ resection was required in 19 patients (35%). Overall actuarial survival was 22% (median survival, 32 months). Unfavorable prognostic factors were incomplete resection, high-grade histologic features, and tumor size of 5 cm or more (P<.05). En bloc resection of contiguous organs did not adversely effect survival. In patients with complete resections, tumor grade was the most important prognostic factor (median survival, 55 months vs 19 months for low-grade vs high-grade tumors; P<.05). CONCLUSIONS: Aggressive surgical resection, including en bloc resection of locally advanced tumors, appears warranted. Despite complete resections, patients with high-grade tumors remain at risk for recurrence.

Adult↗
PubMed2000

HIV antibody profiles in serum and CSF of patients with neurological disease can serve as predictors of outcome.

The serum and CSF antibody profiles were investigated in 100 patients with HIV in relation to the type and severity of neurological disease. Among them, 87 were positive for anti-HIV antibodies in the CSF. In 30 of 87 patients detailed analysis by western blot could be performed. In 20 of 30 the profiles were dissimilar, with more of bands being found in the serum than in the CSF. The correlation of western blot profiles to the clinical outcome indicated that the number of anti-HIV antibody bands as well as the index in the CSF of fatal cases were significantly less compared with non-fatal cases (p=0.019 and p=0.039 respectively).

Adolescent↗
PubMed2000

Analysis of organ physiology in transgenic mice.

The increasing availability of transgenic mouse models of gene deletion and human disease has mandated the development of creative approaches to characterize mouse phenotype. The mouse presents unique challenges to phenotype analysis because of its small size, habits, and inability to verbalize clinical symptoms. This review describes strategies to study mouse organ physiology, focusing on the cardiovascular, pulmonary, renal, gastrointestinal, and neurobehavioral systems. General concerns about evaluating mouse phenotype studies are discussed. Monitoring and anesthesia methods are reviewed, with emphasis on the feasibility and limitations of noninvasive and invasive procedures to monitor physiological parameters, do cannulations, and perform surgical procedures. Examples of phenotype studies are cited to demonstrate the practical applications and limitations of the measurement methods. The repertoire of phenotype analysis methods reviewed here should be useful to investigators involved in or contemplating the use of mouse models.

Animals↗
PubMed2000

Esophageal leiomyomatosis in a woman with a history of vulvar leiomyoma and Barrett's esophagus: a case report and review of the literature.

BACKGROUND: The diagnosis and treatment of esophageal pathology remains a challenge despite advances in preoperative endoscopy, radiographic staging, and perioperative care. CASE REPORT: In this article, we present an interesting case of esophageal leiomyomatosis in a woman with a history of vulvar leiomyoma and Barrett's esophagus. This paper represents the first reported simultaneous occurrence of these three pathologic entities in the English literature. CONCLUSIONS: The clinical presentation and characteristic pathologic findings in patients with esophageal leiomyomatosis are reviewed. Diagnostic and therapeutic approaches to esophageal masses are discussed including the indications for esophageal resection.

Adult↗
PubMed2000

Brachial vascular reactivity in blacks.

Endothelial function was studied ultrasonographically in a healthy subset of African Americans (blacks) because they have an increased risk of hypertension and vascular disease. Twenty-four healthy black and 28 well-matched white subjects were investigated. Ischemia was induced by inflating a cuff over the forearm to 40 mm Hg higher than systolic pressure for 5 minutes. Brachial artery diameter and blood flow velocity were measured at baseline and at 15, 45, and 60 seconds after deflation by use of an Acuson 128XP10 ultrasonograph with a 7.5 MHz transducer. Mean postischemic dilatation, an index of endothelial function, was 1.76+/-0.56% in blacks and 8.79+/-1.22% in whites (P<0.001). Median postischemic vasodilatation in black men [0% (0% to 2.86%)] was not significantly different to that in black women [0.82% (0% to 3.14%)], whereas white women [11.48% (8.70% to 14.29%)] dilated significantly more than white men [4.20% (2.13% to 5.56%)] (P<0.05). Both groups dilated significantly over baseline diameter to sublingual nitroglycerin administration 18.7+/-2.5% (blacks) and 20.2+/-3.2% (whites; P=NS). Mean hyperemic responses did not differ significantly between the 2 subject groups, nor did they differ between men and women of both ethnic groups. We conclude that endothelium-dependent vasodilatation is significantly impaired in healthy, young blacks compared with whites and that gender differences are not seen in blacks with regard to this phenomenon. An impairment in endothelium-dependent NO generation may be a contributing factor to future hypertension and vascular disease in healthy blacks.

Adult↗
PubMed2000

Cytokeratin expression in seminoma of the human testis.

We studied cytokeratin (CK) expression immunohistochemically in 64 seminomas using a panel of commercially available antikeratin antibodies and tested for association of CK expression with patient age, tumor size, stage, and outcome. Seventeen embryonal carcinomas were compared with seminoma. CK7, CAM 5.2, AEI/AEIII, and wide-spectrum screening keratin (WSK) were positive in 41%, 30%, 36%, and 36% of the seminomas, respectively. CK20 and high-molecular-weight keratin (HMWK) were negative in all cases. CD30, placental alkaline phosphatase (PLAP), and epithelial membrane antigen (EMA) were positive in 6%, 100%, and 2% of cases, respectively. There were no differences in patient age, stage, tumor size, or outcome between CK-positive and CK-negative seminomas. CK7, CAM 5.2, AEI/AEIII, and WSK were positive in 100%, 88%, 94%, and 88% of embryonal carcinomas, respectively. CK20 and HMWK were negative in all cases. CD30, EMA, and PLAP were positive in 100%, 12%, and 76%, respectively. CKs are present in seminoma, and their presence is not associated with a difference in patient age, stage, or outcome. In cases such as small needle biopsy specimens, CK and CD30 stains may be useful in separating seminoma from embryonal carcinoma.

Adult↗
PubMed2000

Expedited human immunodeficiency virus testing of mothers and newborns with unknown HIV status at time of labor and delivery.

New York State introduced the first statewide program in the U.S. of expedited HIV testing (48-hour turn-around results) of mothers with unknown HIV status at the time of labor or delivery and their newborns on August 1, 1999. We evaluated the results of this program during its first 5 months at Lincoln Medical and Mental Health Center (Lincoln Hospital) in the Bronx, New York. There were 1,274 total live birth deliveries between August 1 and December 31, 1999. The HIV infection status of 539 mothers (42.3%) was unknown to medical providers in the labor-delivery suite, either due to lack of testing during the current pregnancy or unavailability of HIV documentation at the time of delivery. During labor and delivery, a total of 462 (85.7%) mothers with unknown HIV status consented to expedited HIV testing (Single Use Diagnostic System for HIV-1 antibody or SUDS). The newborns of 77 mothers (14.3%) who did not consent were tested immediately after birth. Seventeen tested positive for HIV-1 antibody by the SUDS test. The results of 10 of these infants (58.8%) were subsequently confirmed positive for HIV-1 antibody by Western Blot analysis. This new rapid HIV testing program facilitated early diagnosis of these previously unknown HIV-exposed infants, although the low positive predictive value of the test in our community calls for careful communication of these results pending confirmation.

Acquired Immunodeficiency Syndrome↗
PubMed2000

A comparative review of generic quality-of-life instruments.

The assessment of health-related quality of life (HR-QOL) is an essential element of healthcare evaluation. Hundreds of generic and specific HR-QOL instruments have been developed. Generic HR-QOL instruments are designed to be applicable across a wide range of populations and interventions. Specific HR-QOL measures are designed to be relevant to particular interventions or in certain subpopulations (e.g. individuals with rheumatoid arthritis). This review examines 7 generic HR-QOL instruments: (i) the Medical Outcomes Study 36-Item Short Form (SF-36) health survey; (ii) the Nottingham Health Profile (NHP); (iii) the Sickness Impact Profile (SIP); (iv) the Dartmouth Primary care Cooperative Information Project (COOP) Charts; (v) the Quality of Well-Being (QWB) Scale; (vi) the Health Utilities Index (HUI); and (vii) the EuroQol Instrument (EQ-5D). These instruments were selected because they are commonly used and/or cited in the English language literature. The 6 characteristics of an instrument addressed by this review are: (i) conceptual and measurement model; (ii) reliability; (iii) validity; (iv) respondent and administrative burden; (v) alternative forms; and (vi) cultural and language adaptations. Of the instruments reviewed, the SF-36 health survey is the most commonly used HR-QOL measure. It was developed as a short-form measure of functioning and well-being in the Medical Outcomes Study. The Dartmouth COOP Charts were designed to be used in everyday clinical practice to provide immediate feedback to clinicians about the health status of their patients. The NHP was developed to reflect lay rather than professional perceptions of health. The SIP was constructed as a measure of sickness in relation to impact on behaviour. The QWB, HUI and EQ-5D are preference-based measures designed to summarise HR-QOL in a single number ranging from 0 to 1. We found that there are no uniformly 'worst' or 'best' performing instruments. The decision to use one over another, to use a combination of 2 or more, to use a profile and/or a preference-based measure or to use a generic measure along with a targeted measure will be driven by the purpose of the measurement. In addition, the choice will depend on a variety of factors including the characteristics of the population (e.g. age, health status, language/culture) and the environment in which the measurement is undertaken (e.g. clinical trial, routine physician visit). We provide our summary of the level of evidence in the literature regarding each instrument's characteristics based on the review criteria. The potential user of these instruments should base their instrument selection decision on the characteristics that are most relevant to their particular HR-QOL measurement needs.

Activities of Daily Living↗
PubMed2000

Genetic analysis of litter size in Targhee, Suffolk, and Polypay sheep.

Data on litter size, weaning weights at 60, 90, and 120 d, postweaning gains from weaning to 120 or 365 d of age, fleece weight, and fiber diameter from Targhee, Suffolk, and Polypay flocks participating in the U.S. National Sheep Improvement Program were used to estimate genetic parameters for litter size and genetic relationships between early-life traits and future litter size. Records on 7,591 lambings by 3,131 Targhee ewes, 10,295 lambings by 5,038 Suffolk ewes, and 6,061 lambings by 2,709 Polypay ewes were used. Heritability estimates for litter size ranged from .09 to .11 across breeds; repeatability ranged from .09 to .13. Additive genetic effects on litter size were generally positively, and occasionally significantly, correlated with animal additive genetic effects on weaning weights and postweaning gains. Genetic correlations (r(a)) ranged from .08 to .48 in Targhee and from .17 to .43 in Suffolk but were close to 0 in Polypay (-.14 to .09). Additive maternal effects on weaning weight were positively associated with litter size in Suffolk and Polypay; this correlation was negative (-.23 to -.35), but not significant, in Targhee. Fleece weight was not strongly associated with litter size; (r(a) = -.09 to .21). However, fiber diameter had a significant undesirable correlation with litter size (.30) in Targhee. Estimates of phenotypic correlations of litter size with early-life traits were uniformly small (-.02 to .08). Thus, although occasional genetic antagonisms between litter size and early-life traits were observed in these data, none appeared large enough to prevent simultaneous genetic improvement in both traits.

Animals↗
PubMed2000

Changes in nutritional status and morbidity over time among pre-school children from slums in Pune, India.

OBJECTIVE: To investigate changes in nutritional status and morbidity over time among pre-school slum children. DESIGN: Longitudinal. METHODS: Children in the age group of 0-5 years from three slums in Pune (n = 845) were studied for a period of two years. Measurement of weight (up to 20 g) and height (up to 0.1 cm), morbidity (in last 7 days) and clinical assessment was undertaken once every four months. RESULTS: Peak prevalence of malnutrition was observed around 18 months and shorter period (3.5 months) of exclusive breastfeeding was probably responsible. Morbidity was generally higher in rainy season and was associated with wasting but not stunting. Gastrointestinal illness and fever contributed 50% of total morbidity days. Higher morbidity affected significantly growth velocities in weight throughout pre-school age. Height velocities were significantly low upto three years of age but there appeared no scope for catch-up growth as velocities remained similar thereafter. Higher morbidity in younger children (less than 2 years) led to deterioration of nutritional status over time in 30% to 50% children. CONCLUSION: Shorter period of exclusive breastfeeding results in undernutrition at an early age among slum children. Morbidity further deteriorates the nutritional status

Anthropometry↗