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S Rao

Publications and source records attributed to S Rao.

At least 325 records · Page 18Linked to original sources
PubMed1990

Tissue-specific splicing of pro-enkephalin mRNA.

A testis cDNA library derived from 4-6 week-old rats was screened using a 32P-labeled 435 base pair (bp) cDNA probe derived from exon 3 of rat brain proenkephalin (PE). Two positive clones were isolated from an initial screening of approximately 20,000 recombinant bacteriophage plaques. The longest insert (1,500 bp) was sequenced and was found to contain a portion of intron A at the 5'-terminus. Intron B was sliced as it is in the brain, therefore, the domain structure of the cDNA was intron A-exon 2-exon 3, reading in the 5'-3' direction. Since the translational initiator codon is located at the 5'-terminus of exon 2, the reading frame of PE is unaltered, however, within intron A are 4 upstream AUG codons which exist in a favorable context for initiation of translation. It is probable that translation of PE would be inhibited by the presence of these upstream initiator codons, which may explain the discrepancy between the levels of PE mRNA and opioid peptides in the testis. Hypophysectomy prior to the onset of puberty was found to drastically reduce the level of PE mRNA in the testis and epididymus, suggesting that pituitary factors affect the expression of the PE gene in these tissues, either directly or indirectly.

Animals↗
PubMed1990

Focal segmental glomerulosclerosis in a child with acute lymphoblastic leukemia.

A 13-year-old boy was found to have acute lymphoblastic leukemia 4 months after the diagnosis of nephrotic syndrome was made. Renal biopsy revealed focal segmental glomerulosclerosis (FSGS). While his leukemia remains in remission 7+ years from diagnosis, he requires chronic hemodialysis due to renal failure. The multiple immunosuppressive antileukemia agents he received did not appear to affect the progression of his renal disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Posterior cervical spine stabilization under local anesthesia.

A technique is described for posterior cervical stabilization with spinous process wiring and fusion performed with the patient under local anesthesia and using corticocancellous demineralized bone matrix allograft. In patients with unstable cervical spines, posterior stabilization and fusion with local anesthesia allowed patient interaction with the surgeon during crucial parts of the operation. The technique was well tolerated and no untoward complications occurred. The technique has not been described for the neurologically intact patient with cervical spine trauma. The purpose of this report is to document the facility and advantages of this technique over traditional general anesthesia with autograft use. Nineteen patients were treated surgically at the author's institution. Local anesthesia was used in 12, and general anesthesia was used in 7. Allograft was used in 12 and autologous iliac crest graft was used in 7 patients. The indications for surgery were instability or neurologic deficit. Blood loss and operative times were favorable when compared with general anesthesia and autograft. The fusion extended by one level in 6 of 19 patients. One patient had preoperative neurologic deficit. All 19 follow-up patients were Frankel grade E. There is no need for endotracheal intubation, the patient serves as his or her own spinal cord monitor, and the surgeon is able to be aware immediately of any threat to neurological function. Demineralized bone matrix allograft has been shown to effectively induce osteogenesis by osteoinduction as well as osteoconduction. Its use eliminates the need for autograft harvesting and permits the use of local anesthesia alone for cervical spine posterior stabilization. The more neurologically intact the patient, the more this technique is indicated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Breast-feeding rates among black urban low-income women: effect of prenatal education.

Many factors are associated with low breast-feeding rates among black low-income women. This study examines whether, despite such factors, health professionals' prenatal education of black poor women is associated with increased breast-feeding rates. Black women born in the United States who attended a midwives prenatal clinic (N = 159) were randomly assigned to two types of prenatal education or were followed up in a control group. All women were interviewed on entry into the study and after delivery of their infants. Women assigned to group classes attended at least one session discussing myths, problems, and benefits of breast-feeding. Women assigned to individual prenatal counseling spoke with a pediatrician or nurse practitioner, who discussed breast-feeding topics similar to those covered in the classes. Women in the control group received no additional prenatal education. The three study groups had significantly different percentages of women who breast-fed (controls 22%, classes 46%, individual sessions 53%). Higher percentages of women in the study groups carried out their prenatal plans to breast-feed (controls 50%, classes 86%, individual sessions 62%) or breast-fed despite prenatal plans to bottle-feed (controls 10%, classes 26%, individual sessions 48%). After multivariable analysis controlling for age, prenatal plans to breast-feed, prior breast-feeding experience, perceived support for breast-feeding, education, gravidity, and employment plans, women in intervention groups had a higher likelihood of breast-feeding than control subjects. These findings suggest that an increase in relatively simple, not-too-time-consuming educational efforts in institutions and offices serving black low-income women might yield significant narrowing of the gap in breast-feeding rates between white affluent women and black low-income women.

Adult↗
PubMed1990

Left atrial myxoma.

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1990

Transdifferentiation of ductular cells into hepatocytes in regenerating hamster pancreas.

The transdifferentiation of regenerating pancreatic cells into hepatocytes in the Syrian golden hamster and Fischer rat is an example of the surprising plasticity of cells in the adult animal. While earlier experiments suggested that these might be derived from acinar cells, unequivocal evidence of this in both models has not been forthcoming. In this paper, we document that pancreatic ductular epithelium in the hamster is the cell of origin and that presumptive hepatocytes can be identified morphologically as early as the 3rd day after the induction of regeneration. The patterns of development of various organelles as characterized by their acquisition of liver-specific protein markers parallels those that have been reported by others during the differentiation of embryonic and postnatal hepatocytes. Colloidal gold-labeled antibody staining of carbamoyl phosphate synthetase, a liver-specific mitochondrial enzyme, and catalase, a peroxisomal enzyme, first appeared 60 hours and 4.5 days postregeneration, respectively. At these times, the morphologic features of the hepatocyte phenotype in the pancreas were ambiguous. Morphometric analysis showed that for both enzymes, the number of gold particles/organelle increased to a maximum by the 9th week. In contrast, urate oxidase, a liver-specific peroxisomal enzyme, was not identified by ultrastructural immunochemistry until the 14th day after regeneration and remained at low levels through the 9th week.

Animals↗
PubMed1989

Control of DNA replication and cell growth by inhibiting the export of mitochondrially derived citrate.

When citrate export from mitochondria is blocked with 1,2,3-benzenetricarboxylate (BTC) during the G1/S phase of the cell cycle, both DNA synthesis and cell growth are dramatically inhibited in suspension-grown 70Z/3 murine lymphoma cell cultures sustained under otherwise optimal conditions. Synchronized (G0/G1 or G1/S) and unsynchronized cultures are susceptible to this phenomenon. BTC prevents two requirements from being met. (1) It deprives the cytosol of the acetyl CoA necessary for operation of the cholesterogenesis pathway, thereby depleting the supply of mevalonate (MVA) implicated as a requirement for triggering DNA synthesis. (2) It behaves as a nonmetabolizable divalent cation chelator, reducing the availability of Ca2+ and Mg2+, which, in whole cells are both required for DNA synthesis. Such inhibitions are reversible. In whole cells, removal of the inhibitor yields rapid and complete recovery of DNA synthesis. During the prolonged presence of BTC, the addition of MVA plus the Ca2+ ionophore A23187 allows partial recovery of DNA synthesis. In isolated, DNA synthesizing nuclei, on the other hand, the slight inhibition of DNA synthesis by BTC is reversed merely by addition of Mg2+. We conclude that the uninterrupted production of citrate-derived MVA via the mitochondria, at the G1/S boundary of the cell cycle (i.e., subsequent to peak cholesterol synthesis), is mandatory for initiating the duplication of the cell genome. Consequently, by its mitochondrial site of action, BTC can severely limit the otherwise continuous supply of MVA during late G1, which in turn, prevents entry into the S phase, and thereby cell proliferation.

Animals↗
PubMed1989

Psychiatric referrals in a neuropsychiatric centre.

Consecutive new cases were screened to identify those referred by other specialties. The referred cases were compared with a randomly selected control group from the non referred cases. Referred cases constituted 16.4% of all the clinic new cases but the demographic characteristics were similar to those of the other clinic cases. Functional somatic complaints were significantly more often (p less than 0.01) reported by the referred cases. Depressive and anxiety symptoms were also significantly more often observed in the referred group (p less than 0.01). Most of the referred cases had identifiable psychiatric problems which could be managed in an out-patient setting. Studies on referral patterns and modes of clinical presentation are useful in planning and organising consultation liaison services in general and specialist centres.

Adolescent↗
PubMed1989

Morphology of M. leprae (?) in VS3E medium--a preliminary communication.

In a previous attempted culture of M. leprae in VS2M medium non-acid fast organisms were seen initially and acid fast organisms appeared later. A drop of a sonicated suspension from a subculture of this was inoculated in VS3E medium. The inoculum consisted mostly of acid fast granules. The culture yielded pure growth of acid fast organisms. Morphology typical of M. leprae could be seen only after 60th day of culture.

Culture Media↗
PubMed1989

Evaluation of a phenytoin dosage regimen design and adjustment computer program.

A computer program for phenytoin (PHT) dosing was developed containing seven different menus: two for drug-naive patients, one using an empirical equation, the other using means for Vmax and Km; two for patients in whom either one or two dose rates and steady-state concentrations are available; two for patients with hypoalbuminemia, and uremia, respectively; and one menu that optimizes Vmax and Km from available steady-state concentrations. The program accepts or converts PHT and sodium PHT, and makes blood level correction for the concomitant administration of 25 different drugs. The evaluation of the program was done by retrospective analysis using data from three study pools: group I involved 47 patients from the University Hospital, group II relied upon 29 patient data supplied from a collaborative Veterans Administration study, and group III involved 26 patients from the Children's Hospital. Predictions were made and compared with found data to be within a range of +/- 15, 20, or 25%. For study group III, many individual blood samples were less than 8 micrograms ml-1; hence, saturation kinetics may not have been involved. It is suspected that saturation kinetics in infants may begin at higher levels. Compliance seems to still be a major problem in PHT monitoring and dosage regimen adjustment. Accepting the data as they are, using one or two dose rates with the corresponding blood concentrations resulted overall in 73-86% achieving blood levels within +/- 25% of the predicted value.

Adolescent↗
PubMed1988

Mild asymptomatic primary hyperparathyroidism is not a risk factor for vertebral fractures.

STUDY OBJECTIVE: To determine the prevalence of vertebral fractures in patients with mild asymptomatic primary hyperparathyroidism and to ascertain whether this prevalence is increased in comparison with the rate in a retrospective control group previously studied at the same institution or with current estimates of the risk for vertebral fractures in subjects of similar age. DESIGN: Prospectively collected data were retrospectively analyzed and compared with data from a historical control group at the same institution and with published data. SETTING: The outpatient department of a bone and mineral metabolism clinic. PATIENTS: A consecutive series of patients with mild asymptomatic primary hyperparathyroidism diagnosed between 1 January 1976 and 31 December 1985. Criteria for inclusion in the study were the absence of symptoms due to hyperparathyroidism, no current kidney stone disease, no radiographic evidence of osteitis fibrosa, a serum calcium level of less than 3.00 mmol/L, a serum creatinine level of less than 133 mumol/L, and a forearm bone density value not more than 2.5 standard deviations below the age-, sex-, and race-adjusted normal value. INTERVENTIONS: A conservative nonintervention study. MEASUREMENTS AND MAIN RESULTS: The prevalence of vertebral fractures in 174 patients (mean age, 62 years) with mild asymptomatic primary hyperparathyroidism was 1.7%; in a subset of white women, the prevalence was 2.8%. These rates were not higher than those expected, by comparison with the rate in a retrospective control group or with the risk for vertebral fractures in subjects of similar age, and may even be lower. CONCLUSIONS: The risk for vertebral fractures is not increased in patients with mild asymptomatic primary hyperparathyroidism and is not a reason to recommend surgical intervention in asymptomatic patients. The increased rates of vertebral fractures that occurred in other series are probably due to the use of inappropriate controls and the influence of referral or selection bias, the inclusion of patients with severer disease, and the effect of geographic differences in vitamin D nutrition on the expression of disease. Possible differences between lateral spine and lateral chest radiographs for determining vertebral body shape need further study.

Aged↗
PubMed1988

Downcore sulphur isotope ratios and diatom inferred pH in an artificially acidified Canadian shield lake.

Three gravity cores were removed from near the deepest point in Lake 223 on 9 June 1984, eight years after the Experimental Lakes Area (ELA) staff began the artificial acidification of the lake with sulphuric acid. The first of these cores was analysed for diatoms and pollen stratigraphy while the second and third were analysed for downcore sulphur isotope ratios (H. Thode) and downcore changes in sulphur reducing bacterial densities (S. Rao). Sediment core chronologies were based on lead-210 and cesium-137 data (R. Anderson) and the Ambrosia pollen rise (M. Dickman). Analysis of the first core to the depth of the Ambrosia pollen rise (9 cm) indicated that diatom inferred pH in Lake 223 at the time of the Ambrosia rise (circa 1890) was 6.8-7.0. At a sediment depth of 3 cm the diatom inferred pH was 6.7. Thereafter diatom inferred pH began a decline culminating in the present day (observed) pH range for 1984 (5.3-5.5). At a sediment depth of 1 cm, an increase in the abundance of two benthic alkalophilic diatoms occurred. The increase in the abundance of these diatoms was ascribed to an increase in hypolimnetic alkalinity following the artificial acidification of Lake 223. This is the first time that lake acidification has been linked to an increase in benthic alkalophilic diatoms associated with hypolimnetic alkalinity production following sulphate reduction. Sulphur in the anaerobic (black) sediment layers (0-1.5 cm) was isotopically light relative to the sulphur in the deeper layers. This was due to sulphur isotope fractionation resulting from the bacterial reduction of sulphate to hydrogen sulphide in the anaerobic portion of the water column. A jet black FeS-rich layer in the uppermost 1.5 cm of the lake's sediments was associated with an increase in the abundance of sulphate reducing bacteria (e.g. Desulfovibrio spp.).

Journal Article↗