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Biomedical subjects

S Rao

Publications and source records attributed to S Rao.

At least 163 records · Page 9Linked to original sources
PubMed1999

Relationship between foot pronation and rotation of the tibia and femur during walking.

The purpose of this study was to test the hypothesis that the magnitude and timing of peak foot pronation would be predictive of the magnitude and timing of peak rotation of tibia and femur. Thirty subjects who demonstrated a wide range of pronation participated. Three-dimensional kinematics of the foot, tibia, and femur segments were recorded during self-selected free walking trials using a six-camera VICON motion analysis system. Regression analysis demonstrated that the magnitude and timing of peak pronation was not predictive of the magnitude and timing of tibial and femoral rotation. The lack of a relationship between peak foot pronation and the rotation of the tibia and femur is contrary to the clinical hypothesis that increased pronation results in greater lower extremity rotation. It would seem, therefore, that the relationship between foot pronation and rotation of the lower extremity segments should be assessed on a patient-by-patient basis.

Adult↗
PubMed1999

Sentinel node biopsy and selective lymph node dissection in cutaneous melanoma patients.

Sentinel node biopsy allows an accurate selection of melanoma patients to be submitted to therapeutic dissection. From February 1994 to August 1998, at the National Cancer Institute, S. Pio X Hospital in Milan and Bufalini Hospital in Cesena, 580 sentinel node biopsies were performed in 540 stage I melanoma patients (242 males; 298 females; median age 47). Primary melanoma was located in the trunk in 201 patients, in lower limbs in 242 cases, in upper limbs in 80 cases and in head and neck in 17 patients. Injection of blue dye for sentinel node identification was performed in all cases; 372 patients were submitted to preoperative lymphoscintigraphy and in 272 cases an intraoperatory probe for a radioguided biopsy was utilized. Sentinel node identification rate was 91%. Sentinel node positivity rate was 15%. Frozen sections were examined in 199 cases. Distribution of positive cases according to primary thickness is the following: <1 mm: 1%; 1-1.99 mm: 5%; 2-2.99 mm: 18% and > or =3 mm: 27%. Sentinel node appeared to be the only metastatic node in 77% of patients submitted to dissection. The adoption of preoperative lymphoscintigraphy and the intraoperative use of the gamma probe contributed substantially in S.N. identification. No complications caused by the procedure were reported. Eight patients had a regional node relapse after a negative sentinel node biopsy and were submitted to therapeutic distant dissection. Currently 513 patients are alive with no evidence of disease. Present data confirm the feasibility and safety of sentinel node technique for selection of patients to be submitted to radical node dissection and to eventual adjuvant treatments.

Adolescent↗
PubMed1999

Early onset cerebellar ataxia with retained tendon reflexes (EOCA) and olivopontocerebellar atrophy (OPCA): a computed tomographic study.

Computed tomographic (CT) studies in olivopontocerebellar atrophies (OPCA) and 'early onset cerebellar ataxia with retained tendon reflexes (EOCA)' are few and vary widely in methodology and criteria for cerebellar and brainstem atrophy. In this prospective study, CT scan observations on 26 patients (EOCA-11, OPCA-15) were compared with 31 controls using qualitative and quantitative assessment of cisterns, ventricles and atrophy of brain. Vermian and/or cerebellar hemispheric (predominantly anterior) atrophy was present in 80.8% and both were equally common. Cerebral cortical atrophy (26.9%) and leukoariosis (15.4%) were less frequently seen. Statistically significant atrophy of pons, brachium pontis, cerebellum and midbrain was noted in patient group. No significant differences were observed between EOCA and OPCA groups. Evidence of atrophy did not correlate with either the duration of illness or the severity of cerebellar ataxia in both the groups. The severity of brainstem atrophy in 14 patients with and 12 patients without abnormal brainstem auditory evoked response did not differ significantly. This study highlights the methodology of CT evaluation for brainstem and cerebellar atrophy, draws attention to cerebral atrophy and emphasizes the lack of significant differences in CT morphology between OPCA and EOCA patients.

Adolescent↗
PubMed1999

Evaluation of cytotoxicity of UHMWPE wear debris.

We established a novel method to investigate the phagocytosis of ultra high molecular weight polyethylene using primary macrophage cells by an inverted cell culture method. Abundant wear debris derived from implant materials are generated in aseptic loosening and are deposited in periprosthetic tissues in which they are phagocytized by mono- and multi-nucleated macrophage like cells. Ultra-high-molecular-weight-polyethylene wear debris generated from different sources namely, from laboratory test wear machine, in vivo methods and from knee and hip simulator were mainly used in this investigation. The cytotoxicity index of the different UHMWPE particles obtained from various sources were compared with that of the PE beads and the control without particles by Alamar Blue and Neutral Red assays. The results showed that the cytotoxicity index was significantly lower for the wear debris from the in vivo experiments than that for other particles. SEM analysis were also done to understand the morphology of the wear debris and polyethylene beads and to confirm the phagocytosis process. The mean diameter of the wear debris obtained from the in vivo experiments as estimated from the imaging analysis of the SEM photographs was found to be the least. The inverted cell culture method may be regarded as one of the good methods to study the phagocytosis of UHMWPE by macrophage cells.

Animals↗
PubMed1999

Undernutrition and adolescent growth among rural Indian boys.

OBJECTIVE: To evaluate impact of undernutrition on various adolescent growth parameters among rural Indian boys. DESIGN: Adolescent boys covering 8-18 yr age group were observed longitudinally for a period of 3 years. SETTING: Adolescent boys (n=673) from seven different villages within 30 to 40 km from Pune were studied. METHOD: Six monthly measurements on weight (upto 50 g) and height (upto 0.1 cm) were recorded and age assessment was done from school records with reasonable accuracy. RESULTS: Stunted and underweight boys were lighter (by 4 kg) and shorter (by 8 cm) at 10 yr age compared to their normal counterparts but this difference increased to 12 kg and 10 cm respectively by adulthood. Undernourished boys however, revealed significant height gains at later ages especially beyond 14+ yr, compared to normals suggesting slow, gradual but continual growth. Undernutrition delayed age at take-off and age at PHV by about 2 yr, and lowered attained height at PHV (by 5 cm) and adult height (by 7 cm). CONCLUSION: Normal and maluourished children from the same rural community show wide differences in their adolescent growth performance. Nutritional deprivation thus seems to affect almost all growth parameters and final adult size too.

Adolescent↗
PubMed1999

Cervical positional effects on snoring and apneas.

We examined the effects of cervical position on the Obstructive Sleep Apnea Syndrome (OSAS) through the use of a custom-designed cervical pillow which promoted neck extension. Twelve subjects with OSAS were recruited from a tertiary sleep disorder clinic population. Of the twelve subjects, three had mild cases of OSAS, four had moderate cases, and the remaining five had severe cases. The subjects used their usual pillows during two consecutive recorded baseline nights in our laboratory. The subjects then used the cervical pillow for five days at home, and returned for two consecutive recorded nights at our laboratory while using the cervical pillow. During the nights in our laboratory, the subjects completed questionnaires, were videotaped to record head and body position, and had their breathing parameters recorded during sleep. Subjects with mild OSAS cases had a non-significant improvement in the severity of their snoring and a significant improvement in their respiratory disturbance index with the cervical pillow, while subjects with moderate OSAS cases showed no improvement in these parameters. Subjects with severe OSAS cases showed slight improvement in some measures of their abnormal respiratory events during the experimental period.

Adult↗
PubMed1999

Alterations in monoamine neurotransmitters and dendritic spine densities at the medial preoptic area after sleep deprivation.

The experiments were conducted on 24 adult male Wistar rats to find out the alterations in the levels of monoamines and dendritic spine densities in the medial preoptic area and cortex after total sleep deprivation. Noradrenaline was reduced in the medial preoptic area, though there was no significant change in the cortex. Dopamine and serotonin were decreased both in the medial preoptic area and in the cortex. Dendritic spine counts in the medial preoptic area and the motor cortex were increased after total sleep deprivation. Enhanced release of the monoamines and their subsequent breakdown during sleep deprivation could be responsible for the decreased levels of the transmitters. An increase in synaptic activity, resulting in the enhanced release of the transmitters, might be responsible for the increased spine density after total sleep deprivation. Localized changes in noradrenaline levels at the medial preoptic area suggest its involvement in sleep genesis and maintenance, though its possible contribution to other functions like thermoregulation and reproduction cannot be ruled out. As the available literature does not indicate a role for serotonin and dopamine at the medial preoptic area in sleep regulation, these changes may represent their participation in non-sleep functions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

Lovastatin mediated G1 arrest in normal and tumor breast cells is through inhibition of CDK2 activity and redistribution of p21 and p27, independent of p53.

Previously, we reported that lovastatin, a potent inhibitor of the enzyme HMG CoA reductase also acts as an antimitogenic agent by arresting cells in the G1 phase of the cell cycle resulting in cell cycle-independent alteration of cyclin dependent kinase inhibitors (CKIs). In the present study we have investigated the nature of the CKIs (p21 and p27) alterations resulting in G1 arrest in both normal and tumor breast cell lines by lovastatin. We show that even though lovastatin treatment causes G1 arrest in a wide variety of normal and tumor breast cells irrespective of their p53 or pRb status, the p21 and p27 protein levels are not increased in all cell lines treated suggesting that the increase in p21 and p27 protein expression per se is not necessary for lovastatin mediated G1 arrest. However, the binding of p21 and p27 to CDK2 increases significantly following treatment of cells with lovastatin leading to inhibition of CDK2 activity and a subsequent arrest of cells in G1. The increased CKI binding to CDK2 is achieved by the redistribution of both p21 and p27 from CDK4 to CDK2 complexes subsequent to decreases in CDK4 and cyclin D3 expression following lovastatin treatment. Lastly, we show that lovastatin treatment of 76N-E6 breast cell line with an altered p53 pathway also results in G1 arrest and similar redistribution of CKIs from CDK4 to CDK2 as observed in other breast cell lines examined. These observations suggest that lovastatin induced G1 arrest of breast cell lines is through a p53 independent pathway and is mediated by decreased CDK2 activity through redistribution of CKIs from CDK4 to CDK2.

Antineoplastic Agents↗
PubMed1998

Myocyte enhancer factor-related B-MEF2 is developmentally expressed in B cells and regulates the immunoglobulin J chain promoter.

Immunoglobulin J chain gene expression is induced by the delivery of a lymphokine signal to antigen-activated B cells in a primary immune response. A major interleukin 2 (IL-2)-responsive region that contains two adjacent control elements (JA and JB) exists within the J chain promoter. Transcription factor PU.1 positively regulates J chain gene expression by binding to one of the control elements (JB) in the J chain promoter. In the present study we have determined that a myocyte enhancer factor 2 (MEF2)-related nuclear factor, named B-MEF2, positively regulates the J chain gene promoter activity via the second control element (JA). An in vitro translated MEF2 family member, MEF2C, was found to bind the JA site with identical properties as endogenously expressed B-MEF2 in B cell lines. Moreover, in vivo experiments showed that a dominant negative mutant of MEF2C blocked B-MEF2 regulation of the J chain promoter. Consistent with its role as positive regulator of J chain gene expression, B-MEF2 levels were enhanced in highly differentiated B cells. In addition, induction of an IL-2-responsive presecretor cell line BCL1 with IL-2 or IL-5 (which up-regulates J chain gene expression) resulted in an increased expression of B-MEF2. We conclude that a MEF2-related transcriptional factor, B-MEF2, acts as a stage-specific positive regulator of J chain gene expression in the B cell lineage.

Animals↗
PubMed1998

Knee kinetics in trans-tibial amputee gait.

This study evaluated the mechanics of the knee during gait in persons with trans-tibial amputations. Spatiotemporal, kinematic, kinetic, and electromyographic data (EMG) were collected from ten individuals with trans-tibial amputations and ten control subjects during level walking. Results found that the trans-tibial amputee (TTA) group had significantly greater EMG activity of the knee extensors and knee flexors compared to normal. The muscle action of the TTA group was inconsistent with the knee kinetic data as demonstrated by a minimal external knee flexion moment and negligible knee power. The discrepancy between the mechanical and physiological measures of knee demand in this population illustrates the need for an integrated approach for the study of joint function during gait (i.e. EMG in combination with kinetic measures). Copyright 1998 Elsevier Science B.V.

Journal Article↗
PubMed1998

The transcription factor NF-kappaB/p50 interacts with the blk gene during B cell activation.

The B cell-specific transcription factor Pax-5 has been shown previously to interact with the promoter of the blk gene in vitro. blk encodes a tyrosine kinase associated with the B cell receptor, which is expressed during the early but not the final stages of B cell development. To investigate whether Pax-5 regulates expression of the blk gene in vivo during B cell development and/or activation, Pax-5a was overexpressed in B cell lines. Increases in blk promoter activity using a chloramphenicol acetyltransferase reporter gene system suggested a role for Pax-5a as a transcriptional activator. Subsequent site-specific mutagenesis studies showed that mutations of the Pax-5 binding site on blk significantly alter promoter activity, although results suggested that other factors could bind to this region as well. Using mobility shift assays, we detected an inducible transcription factor that interacts strongly with a sequence overlapping the Pax-5 site on the blk promoter and identified this as a homodimer of NF-kappaB/p50, a member of the NF-kappaB/Rel family of transcription factors. This factor was present at high levels in lipopolysaccharide-activated normal B cells and in plasma cell lines but either at low levels or undetectable levels in resting normal B cells or pre-B or mature B cell lines. In contrast, lipopolysaccharide induction of a pre-B cell line (703/Z) induced a complex that contained both NF-kappaB/p50 and p65. These studies suggest that different NF-kappaB complexes are able to interact with a sequence overlapping the Pax-5 site on the blk promoter and that the relative levels of "bound" factor influence levels of blk expression. Since p50 homodimers and p50/p65 heterodimers of the NF-kappaB complex should have opposing effects on blk transcription, this could provide a mechanism to differentially regulate blk expression during B cell development and activation.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Evaluation of hemispheric dominance for language using functional MRI: a comparison with positron emission tomography.

The utility of a conventional (i.e., nonecho-planar) functional magnetic resonance imaging (fMRI) technique to determine hemispheric dominance for language was assessed using a semantic generation task in which subjects were presented with a series of nouns and generated aloud a verb for each one. A direct comparison of the fMRI results with positron emission tomography (PET), acquired from the same subjects, was also performed. When analyzed by group averaging, the results of this work were in concordance with those of previous PET studies, showing a left hemispheric dominance for language. Analyzed on a individual basis, 7 out of 9 subjects were left-hemisphere dominant and 2 subjects were right-hemisphere dominant; this applied with both PeT and fMRI methods. The direct comparison between PET and fMRI further demonstrated that fMRI can replicate PET findings. Of the total activation foci detected by PeT, 92% were observed by fMRI. On the other hand, fMRI reported 64% more activations than did PET. This may reflect differences in procedure, spatial resolution, sensitivity, and the underlying physiological mechanism between PET and fMRI. This study suggests that the fMRI technique, even using conventional MRI scanners, could be clinically useful in evaluating hemispheric dominance for language on an individual subject-by-subject basis.

Adult↗
PubMed1998

Sympathetic skin response in myelopathies.

Autonomic dysfunctions cause significant morbidity and mortality among patients with spinal cord disorders. Sympathetic skin response (SSR), a simple, noninvasive electrophysiological technique, may be useful for assessing sympathetic functions in patients with myelopathies. Our aim was to study SSR in patients with myelopathy and correlate it with clinical features, severity of the impairment, somatosensory evoked potentials. and outcome. Thirty patients (15 men, 15 women) 12 to 60 years old with myelopathies of different etiology were studied. Subjects with clinical, electrophysiologic, or radiologic evidence of lesions outside the spinal cord were excluded. Somatosensory evoked potentials (SSEP) were recorded from scalp with median nerve stimulation at the wrist and posterior tibial nerve below the medial malleolus. The SSR was recorded from palm and sole after stimulating the supraorbital nerve at forehead, median nerve at wrist, and posterior tibial nerve below medial malleolus. The SSR was considered abnormal when absent. The sites of the lesions in these patients were cervical (13), thoracic (16), and lumbar (1). The lesion was clinically complete in six patients. Good motor recovery was noted in 16 subjects. SSR was absent from sole in 25 and palm in 10 patients from all three sites of stimulation. In addition, three patients also had absent SSR from palm on posterior tibial nerve (PTN) stimulation. SSEP was absent from median (N19) in three and posterior tibial (N39) in 20 patients. Among 10 patients with absent SSR from palm, only three had a good outcome. Presence of SSR from palm to PTN stimulation correlated with sparing of bladder sensations and good outcome. However, absent SSR from sole did not correlate with clinical features, bladder dysfunction, or outcome. Sympathetic skin response is frequently abnormal in patients with myelopathies. Spinal afferent and efferent tracts for SSR are different and may be affected individually. The afferent pathways are closely related to tracts conveying bladder sensation. Preserved palmar SSR on PTN stimulation may suggest good motor outcome. SSR may be a valuable adjunct in evaluating patients with myelopathies.

Adolescent↗
PubMed1998

Chemotherapy of oesophago-gastric cancer.

Oesophageal and gastric cancers are common tumors that represent a number of challenges for oncologists, gastroenterologists and surgeons. The prognosis remains poor with the majority of patients presenting with advanced disease. Combined chemotherapy and radiotherapy has demonstrated a survival benefit in patients with loco-regional oesophageal cancer compared to radiotherapy alone. In an interim analysis we have observed a 62% response rate using a chemoradiation regimen based on protracted venous infusion of 5-fluorouracil and cisplatin combined with radiotherapy in patients with inoperable oesophageal cancer. Improved outcomes with loco-regional disease has rekindled interest in preoperative therapy. In a trial comparing preoperative chemoradiation to surgery alone in patients with operable oesophageal adenocarcinoma, survival was improved with multimodality treatment. In addition, a study including both adeno- and squamous carcinomas demonstrated a trend towards improved survival. A complete pathological response to chemoradiation was associated with significantly improved survival. Gastric cancer is one of the most chemosensitive solid tumors of the gastrointestinal tract with the majority of patients being suitable for palliative chemotherapy. The ECF (epirubicin, cisplatin, protracted venous infusion 5-fluorouracil) regimen was developed in the Gastrointestinal unit of the Royal Marsden Hospital and first reported in 1991. In a prospective randomised trial including 274 patients ECF has been compared with the standard combination of 5-fluorouracil, adriamycin and methotrexate (FAMTX) in patients with previously untreated gastric cancer. Overall response rate, failure-free and overall survival were significantly improved with ECE, ECF also demonstrated improved quality of life and cost effectiveness when compared to the FAMTX regimen. ECF should now be regarded as the standard treatment for advanced oesophago-gastric cancer against which new therapies should be compared. In addition the Medical Research Council are conducting a trial randomising patients between surgery alone and perioperative chemotherapy using the ECF regimen in operable gastric cancer.

Antineoplastic Agents↗
PubMed1998

Corrosion resistance, mechanical properties, corrosion fatigue strength and cytocompatibility of new Ti alloys without Al and V.

The effects of various metallic ions using various metallic powders on the relative growth ratio of fibroblasts L929 and osteoblasts MC3T3-E1 cells were carried out. Ti, Zr, Sn, Nb and Ta had evidently no effect on the relative growth ratios of cells. Otherwise, Al and V ions exhibit cytotoxicity from a concentration of > or = 0.2 ppm. This Al effect on cells tend to be stronger in medium containing small quantity of V ions (< or = 0.03 ppm). The new Ti-15%Zr-4%Nb-4%Ta-0.2%Pd alloy exhibited a higher corrosion resistance in physiological saline solution. The addition of 0.02%O and 0.05%N to Ti-Zr alloy improved the mechanical properties at room temperature and corrosion fatigue strength. The relative growth ratios for the new Ti alloy plate and the alloy block extraction were unity. Further, the relative growth ratios were almost unity for the new Ti alloy against apatite ceramic pins up to 10(5) wear cycles in Eagle's MEM solution. However, there was a sharp decrease for Ti-6%Al-4%V ELI alloy from 3 x 10(4) wear cycles as V ion was released during wear into the wear test solution since the pH of the Eagle's MEM increases with increasing wear cycles.

3T3 Cells↗
PubMed1998

Psychological well-being among cancer patients receiving radiotherapy--a prospective study.

The impact of cancer on the psychological well-being of newly diagnosed cancer patients before and during the course of radiotherapy was assessed in 70 consecutive cancer patients. Most of the patients were over 40 years of age, women, illiterate and from a lower socioeconomic group. During the course of treatment there was a decrease in the well-being scores on some dimensions such as perceived family and primary group support. Improvements were seen in the dimensions of positive feelings, coping, social support other than the family and spiritual well-being. There were no changes in the dimensions of negative feelings and perceived ill-health. The results give a profile on well-being and the changes observed during radiotherapy.

Adaptation, Psychological↗
PubMed1998

Mapping quantitative trait loci for ordered categorical traits in four-way crosses.

Many quantitative traits of economical importance are ordinal in nature. Although methods of mapping quantitative trait loci (QTLs) for continuous quantitative characters are well developed, such methods for ordinal characters are generally lacking. In this paper, we develop a method based on the framework of a generalized linear model using four-way cross populations. The method estimates and tests the average effects of a gene substitution in the parents. All markers in the same linkage group are simultaneously used to infer the allelic transmission of a putative QTL. General results of the method are demonstrated by a few simulation experiments. We discuss extensions of the method to QTL mapping in full-sib families.

Animals↗