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Biomedical subjects

P Rao

Publications and source records attributed to P Rao.

At least 55 records · Page 3Linked to original sources
PubMed1998

Erythrocyte indicators of oxidative stress in gestational diabetes.

Foetuses born to mothers with gestational diabetes are at increased risk of developing respiratory distress, foetal macrosomia, foetal anomalies and platelet hyperaggregability. High blood glucose level induces oxidative stress and decreases antioxidant defences. The present study discusses the possibility of lipid peroxidation and protein oxidation in both maternal and foetal erythrocytes as an indicator of oxygen radical activity. The level of lipid peroxidation and protein oxidation in erythrocytes was estimated in 20 mothers with gestational diabetes and their newborns. The maternal age varied between 19 and 42 y and foetal age ranged between 34 and 39 weeks. The proteolytic activities in the erythrocyte lysates obtained from mothers with gestational diabetes and their newborns were significantly greater [(mean +/- SD) 24.41 +/- 9.05 and 16.70 +/- 3.36 microM of amino groups/g haemoglobin, n = 20, respectively] than those from control group (10.18 +/- 4.84 and 14.64 +/- 6.21 microM amino groups/g haemoglobin, n = 15, respectively; p < 0.05 in both cases). Similarly erythrocyte malondialdehyde levels were significantly elevated in babies born to mothers with gestational diabetes (10.11 +/- 2.21 nM/g haemoglobin) when compared to controls (6.8 +/- 3.75 nM/g haemoglobin) (p < 0.05). In the erythrocytes of mothers with gestational diabetes, malondialdehyde levels correlated significantly with glycated haemoglobin levels (p < 0.01). The results of this study indicate that the oxidative stress induced by gestational diabetes manifests as increased lipid peroxidation and protein oxidative damage in the erythrocytes of both mothers with gestational diabetes and their newborn infants.

Adult↗
PubMed1998

Myelolipoma: CT and pathologic features.

PURPOSE: To correlate clinical and pathologic patterns of myelolipoma with the computed tomographic (CT) appearance. MATERIALS AND METHODS: All cases of myelolipoma accessioned by the Armed Forces Institute of Pathology from 1981 through 1997 were reviewed. CT images were scored for the location and size of each myelolipoma and the presence of calcification, hemorrhage, fat, and pseudocapsule. Pathologic findings for the pattern of fat and bone marrow elements were correlated with CT findings. RESULTS: In 74 patients, 86 myelolipomas were found, of which 72 were in an adrenal gland (eight were bilateral), and 14 extra-adrenal masses were found in 10 patients. Four clinicopathologic patterns emerged: (a) isolated adrenal myelolipoma in 37 patients (fat evident at CT, no other disorders present); (b) myelolipoma with hemorrhage in nine patients (imaging features similar to those of isolated adrenal myelolipomas but larger [mean diameter, 14.2 vs 9.9 cm; P = .01]; (c) extra-adrenal myelolipoma in 10 patients (imaging findings similar to those of adrenal myelolipomas, found most often in the retroperitoneum); and (d) myelolipomatous foci within other adrenal pathologic conditions in 18 patients (smaller, lower fat content, more heavily calcified). CONCLUSION: Myelolipomas are adrenal or extra-adrenal masses, with hemorrhage more common in larger lesions (diameter, > 10 cm). The CT appearance of myelolipomatous foci, which can be found within other pathologic adrenal conditions, is different from that of isolated adrenal myelolipomas.

Adipose Tissue↗
PubMed1998

Systematic analysis of STD control: an operational model.

BACKGROUND: Sexually transmitted diseases (STDs) enhance HIV transmission, and improved management of STD in primary health care decreases HIV incidence. In resource poor countries, those responsible for planning and managing STD control programmes need to be able to analyse the STD situation in their setting and the interventions which are therefore likely to be most cost effective. However, the data required for such decision making are often not available in developing countries. This paper presents an operational model, developed as a practical tool to support planning, monitoring, and evaluation of STD intervention strategies in settings where data are unavailable or inadequate. METHOD: The operational model is based on the approach developed for estimating the effectiveness of control measures in tuberculosis programmes. Using available data, the model takes a step by step approach. It begins with analysis of the total male and female population, the proportion of men and women aged 15-49 years, and the proportion of these who are sexually active. Subsequent steps analyse numbers with STDs, and loss of cases to the health system at each stage between infection and cure. The model was tested in Nairobi, Kenya using available demographic, epidemiological, and public health data; no original data were collected. Data for the total population of Nairobi were not available to illustrate all the steps in the model. For these steps, relevant information was taken where available from a specific study population using a large STD referral centre. RESULTS: Despite the lack of precise data for Nairobi, the model highlighted sex imbalances in population, which has potential implications for STDs. It also showed significant disparities in terms of public health policy--for example, between the number of people infected with STDs and the number who have symptoms, and between the number with symptoms and those who seek treatment from public health facilities. It also showed differences between the numbers who attend a health facility, and those that are correctly diagnosed and treated, and, of these, the proportion that are cured. CONCLUSION: Even where data are incomplete or not available, the model can be a useful tool for analysis. Application of the model, as the Nairobi example illustrates, provides a useful starting point in terms of determining both general and specific determinants of STDs, identifying problems, highlighting significant sex differences, and indicating where it might be appropriate to focus interventions. The model showed that, in Nairobi, only a small proportion of STD cases are removed from the reservoir of infection in the community through curative services, that cases are lost to the health services at every step, and therefore that interventions are required at every step to achieve comprehensive STD control. It highlights the need for strategies to prevent infections, to identify and treat those with and without symptoms, to motivate those who are aware of their infection to seek treatment, and to improve the effectiveness of partner notification and treatment. Finally, the model points to areas where data are inadequate and where STD control programmes need to concentrate information collection efforts.

Adolescent↗
PubMed1998

[An improved method of cholesterol determination in egg yolk by high performance liquid chromatography].

An improved method for cholesterol determination in egg yolk is reported in this paper. Egg yolk was first diluted. Cholesterol was then extracted with ethyl ether and petroleum ether, and quantified by reversed phase liquid chromatography on a Zorbax ODS column (0.46 mm x 15 cm, 5-6 microns) using a mobile phase of acetonitrile and 2-propanol (4:1) with a flow rate of 0.6 mL/min. A linear correlation was observed between 0.05-0.40 g/L of cholesterol. The determination limit was 0.02 g/L. This proposed method of HPLC determination of egg yolk without saponification is superior to colorimetric determination on the sample with saponification, and comparable to HPLC determination with saponification of the egg yolk sample in terms of reliability. No difference in final results was observed between egg yolk sample with saponification and the same sample without saponification. Rapid and reproducible quantification of cholesterol in egg yolk can be completed with this new method. Omission of saponification has made this proposed method more convenient than those ever reported, and can be used in yolk cholesterol study with greater ease.

Cholesterol↗
PubMed1998

Fetus in fetu.

Fetus in fetu occurs due to aberration of monozygotic twinning. A 16-year-old boy presented with abdominal pain and mass. Laparotomy revealed an anencephalic fetus within an encapsulated retroperitoneal mass. Pathologic examination confirmed rib formation with a primitive vertebral column with bone marrow. There was no other organogenesis.

Adolescent↗
PubMed1998

Wandering spleen causing splenic flexure volvulus and obstruction.

A 48-year-old woman presented with symptoms of distal bowel obstruction. On examination she had abdominal distension and a lump in the left lumbar and iliac regions. X-ray revealed distension of the colon with dilated small bowel. Exploration revealed an enlarged ptotic spleen whose pedicle caused obstruction of the colon. There was concomitant partial volvulus of the splenic flexure around the splenic pedicle. The splenic vein was thrombosed. Splenectomy was performed.

Colonic Diseases↗
PubMed1997

Colchicine down-regulates lipopolysaccharide-induced granulocyte-macrophage colony-stimulating factor production in murine macrophages.

Activation of macrophages by LPS and taxol results in production of IL-1, IL-6, TNF-alpha, and granulocyte-macrophage CSF (GM-CSF), which are involved in regulating hemopoiesis, inflammation, and immune responses. Microtubules are proposed as a target site for LPS interaction(s), based on similarities between the effects of the tubulin-binding drug taxol and LPS. To clarify the role of microtubules in LPS-induced GM-CSF expression in macrophages, we examined whether microtubule depolymerizing agents affect GM-CSF production in macrophages. Pretreatment with colchicine impaired LPS induction of GM-CSF in RAW 264 cells, and studies using stable transfectants revealed that colchicine impaired the transcriptional responsiveness of a reporter gene driven by a GM-CSF promoter sequence. Colchicine inhibition of the GM-CSF response correlated with decreases in the mRNA levels of beta-tubulin; maximal inhibition of both events was observed 4 h after addition of colchicine. Microtubule agents inhibited LPS induction of IL-6 and TNF-alpha, while the induction of both IL-1beta and inducible nitric oxide synthase was unaltered, suggesting that LPS activates microtubule-dependent and -independent pathways. Interestingly, LPS stimulation of macrophages down-regulated levels of beta-tubulin transcripts, implying that LPS interacts with an element(s) of the microtubule network in vivo, activating pathways regulating transcription of beta-tubulin. The ability of both colchicine and LPS to modulate transcription of beta-tubulin suggests that this event does not per se underlie the inhibitory effect of colchicine on LPS-induced GM-CSF expression. These data led us to conclude that colchicine inhibits LPS induction of GM-CSF by affecting microtubule-dependent costimulatory signaling pathways that synergize with primary LPS-triggered responses.

Animals↗
PubMed1997

High expression of the chemokine receptor CCR3 in human blood basophils. Role in activation by eotaxin, MCP-4, and other chemokines.

Eosinophil leukocytes express high numbers of the chemokine receptor CCR3 which binds eotaxin, monocyte chemotactic protein (MCP)-4, and some other CC chemokines. In this paper we show that CCR3 is also highly expressed on human blood basophils, as indicated by Northern blotting and flow cytometry, and mediates mainly chemotaxis. Eotaxin and MCP-4 elicited basophil migration in vitro with similar efficacy as regulated upon activation normal T cells expressed and secreted (RANTES) and MCP-3. They also induced the release of histamine and leukotrienes in IL-3-primed basophils, but their efficacy was lower than that of MCP-1 and MCP-3, which were the most potent stimuli of exocytosis. Pretreatment of the basophils with a CCR3-blocking antibody abrogated the migration induced by eotaxin, RANTES, and by low to optimal concentrations of MCP-4, but decreased only minimally the response to MCP-3. The CCR3-blocking antibody also affected exocytosis: it abrogated histamine and leukotriene release induced by eotaxin, and partially inhibited the response to RANTES and MCP-4. In contrast, the antibody did not affect the responses induced by MCP-1, MCP-3, and macrophage inflammatory protein-1alpha, which may depend on CCR1 and CCR2, two additional receptors detected by Northern blotting with basophil RNA. This study demonstrates that CCR3 is the major receptor for eotaxin, RANTES, and MCP-4 in human basophils, and suggests that basophils and eosinophils, which are the characteristic effector cells of allergic inflammation, depend largely on CCR3 for migration towards different chemokines into inflamed tissues.

Basophils↗
PubMed1997

Degradation of glycated hemoglobin. Role of erythrocytic proteolytic enzymes and oxidant damage.

Glycated hemoglobin can be degraded by proteolytic enzyme(s) in the erythrocyte. The enzyme(s) co-elutes with glycated hemoglobin when the latter is separated from erythrocyte lysates using the cation-exchanger Bio Rex-70. A further purification of the Bio Rex eluant on DEAE Sephadex A-50 separated the enzyme(s) from glycated hemoglobin. Studies with the Bio Rex eluant showed that degradation of glycated hemoglobin is maximum at 37 degrees C at pH 8.6. Proteolytic degradation is inhibited by 5 mM N-ethylmaleimide (NEM), 5 mM ethylenediamine tetraacetic acid (EDTA) and 0.6 mM n-p-tosyl-L-lysine choromethyl ketone (TLCK) (100-87 and 76% inhibition respectively). This study also examines the possibility that oxidative-damage to glycated hemoglobin increases its susceptibility to proteolytic degradation. When incubated with various anti-oxidants like DTPA, uric acid, mannitol and butylated hydroxy toluene (BHT), proteolytic degradation of glycated hemoglobin decreased by 66.1, 50.7 and 38% respectively.

Antioxidants↗
PubMed1997

IL-6 induction of protein-DNA complexes via a novel regulatory region of the inducible nitric oxide synthase gene promoter: role of octamer binding proteins.

Macrophage inducible nitric oxide synthase (iNOS) catalyzes the synthesis of NO. IL-6-stimulated macrophage differentiation of murine myeloid M1 cells is accompanied by iNOS gene induction and steady-state mRNA expression. Two regions within the iNOS promoter mediate transcriptional responsiveness to LPS and IFN-gamma. Region I contains several essential transcription factor binding motifs and promotes responsiveness to LPS, whereas region II potentiates the LPS response by IFN-gamma. Because region I possesses basal promoter activity and directly mediates iNOS gene activation, we attempted to identify the trans-acting factors involved in IL-6-stimulated induction of the murine iNOS gene through this region. Using an electrophoretic mobility shift assay and methylation interference, we show that IL-6 induced reciprocal changes in the binding activity of POU family members to the candidate nonconsensus octamer sequence of region I that correlated, temporally, with iNOS steady-state mRNA expression. Although DNA-protein binding activity of IL-6-stimulated whole-cell extracts also interacted with a radiolabeled canonical octamer motif, such DNA-protein complexes were not eliminated in competition assays using consensus nuclear factor kappaB or IL-6 oligonucleotides. Specifically, our studies show that octamer binding protein-1-related protein binding activity decreased, while binding of octamer binding protein-2-related proteins increased during differentiation. Mutation of the octamer motif disrupted both binding of the IL-6-induced protein-DNA interactions and transcriptional activation through region I, revealing that this motif is absolutely essential for IL-6 induction of iNOS. Thus, differential activation of octamer binding transcriptional modulators from the POU family may be a novel mechanism of IL-6-mediated iNOS gene regulation.

Animals↗
PubMed1997

Chemokine receptor usage by human eosinophils. The importance of CCR3 demonstrated using an antagonistic monoclonal antibody.

Chemokines bind and signal through G-protein coupled seven transmembrane receptors. Various chemokine receptors are expressed on leukocytes, and these may impart selective homing of leukocyte subsets to sites of inflammation. Human eosinophils express the eotaxin receptor, CCR3, but respond to a variety of CC chemokines apart from eotaxin, including RANTES, monocyte chemotactic protein (MCP)-2, MCP-3, and MCP-4. Here we describe a mAb, 7B11, that is selective for CCR3 and has the properties of a true receptor antagonist. 7B11 blocked binding of various radiolabeled chemokines to either CCR3 transfectants, or eosinophils. Pretreatment of eosinophils with this mAb blocked chemotaxis and calcium flux induced by all CCR3 ligands. In all individuals examined, including allergic and eosinophilic donors, > 95% of the response of eosinophils to eotaxin, RANTES, MCP-2, MCP-3, and MCP-4 was shown to be mediated through CCR3. The IL-8 receptors, particularly CXCR2, were induced on IL-5 primed eosinophils, however these eosinophils responded to CC chemokines in the same manner as unprimed eosinophils. These results demonstrate the importance of CCR3 for eosinophil responses, and the feasibility of completely antagonizing this receptor.

Antibodies, Monoclonal↗
PubMed1997

Influence of dietary fat on the activities of subcellular membrane-bound enzymes from different regions of rat brain.

The effect of different dietary fats with varying degrees of unsaturation and essential fatty acid composition, which are commonly consumed in India, on the activity of some important membrane-bound enzymes was assessed in different brain regions of rat. Four groups of male CFY weanling rats were fed nutritionally adequate diets containing groundnut, coconut, safflower or mustard oil as fat source at 20% level for 16 weeks. The synaptosomal, microsomal and myelin membranes were prepared from three brain regions, viz., cerebrum, cerebellum and brain stem from each group. The activities of Na+, K(+)-ATPase, Mg(2+)-ATPase and acetylcholinesterase were assayed and the fatty acid composition was determined in these subcellular membrane fractions. The safflower oil-fed group showed higher Na+, K(+)-ATPase activity in most membrane fractions than the coconut or mustard oil-fed groups. The Mg(2+)-ATPase activity was found to be similar amongst all groups in all the brain regions. The synaptosomal acetylcholinesterase activity was distinctly higher in coconut and groundnut oil-fed groups when compared to safflower or mustard oil consuming groups. Alterations in the activities of these subcellular membrane-bound enzymes are expected to exert a significant impact on the electrophysiological and metabolic functions of brain. Results of the present study show that depending on the nature of dietary fat the fatty acid composition of subcellular membranes is altered, which in turn could regulate the activity of membrane-bound enzymes that are vital for brain function.

Acetylcholinesterase↗
PubMed1997

[Deviation of size-exclusion chromatographic behavior of tryptophan on TOYOPEARL HW-40S column].

A deviation of size-exclusion chromatographic behavior of amino acids on TOYOPEARL HW-40S column is reported. On the column 18 amino acids were not eluted in the same fraction in the total volume, but separated into 5 fractions with tryptophan as the last one far behind the total volume. Interaction between tryptophan and the matrices was investigated under different conditions in order to elucidate the chemical nature of the deviation. It was found that addition of trifluoroacetic acid and sodium chloride of high concentration in mobile phase, dramatically increased the retention time of trypophan, while addition of acetonitrile, sodium chloride of lower concentration and the hydrogen bond breaker urea reduced the interaction. It is concluded that adsorption of tryptophan on TOYOPEARL HW-40S is basically due to the hydrophobic nature with limited influence of hydrogen bond and ionic interaction. The former factor can be eliminated by keeping acentonitrile concentration over 50% (V/V), while the latter two can be reduced to the minimum by adding 0.17mol/L sodium chloride and 3.51mol/L urea. The results not only lead to better understanding of size-exclusion chromatography of this matrices, but also help to apply hydrophobic chromatography of this matrices to the isolation of amino acids and peptides.

Amino Acids↗
PubMed1997

Imaging of pediatric liver tumors.

Primary pediatric liver tumors are a unique group of neoplasms. The age at presentation, clinical sigma symptoms, and imaging characteristics provide helpful clues in making a prospective diagnosis and in tailoring a differential diagnosis. The role of imaging is fourfold: characterization, localization, determination of resectability, and follow-up use. MR is usually complementary to ultrasound and CT.

Bile Duct Neoplasms↗
PubMed1997

Estimating the daily dialysate drain volume required in CAPD for a target peritoneal creatinine clearance by body water and peritoneal transport characteristics.

Stepwise logistic regression performed in 324 clearance studies in 194 patients identified daily drain volume normalized by body water (DV/V) and peritoneal solute transport type as the predictors of peritoneal creatinine clearance (CCrp) in continuous ambulatory peritoneal dialysis (CAPD). Solution of the regression model for DV/V provided DV/V values predicted to provide a desired CCrp at different probabilities. The ability of the predicted DV/V to detect desired CCrp values was tested in a new set of 359 clearance studies in 217 CAPD patients who had a peritoneal equilibration test within 12 months of the clearance study. No patient with low transport had a CCrp exceeding 54 L/1.73 m2 weekly. The following DV/V values detected CCr > or = 54 L/1.73 m2 weekly with a probability of at least 80%: for low-average transport, 0.406 L/L per 24 hours; for high-average transport, 0.339 L/L per 24 hours; for high transport, 0.241 L/L per 24 hours. Corresponding DV/V values for a CCrp of 60 L/1.73 m2 weekly were as follows: for high-average transport, 0.351 L/L per 24 hours; for high transport, 0.271 L/L per 24 hours. For high-average transport, maximal body surface area (BSA) estimates allowing a CCrp of 60 L/1.73 m2 weekly at a CAPD schedule of four daily exchanges with 3-L exchange volume and 1.5 L/24 hour ultrafiltration volume, and with the specified DV/V values were 2.03 m2 in women and 1.77 m2 in men. Corresponding BSA estimates for high peritoneal solute transport were 2.58 m2 in women and 2.21 m2 in men. The delivered dose of CAPD, expressed as DV/V, required to achieve a target CCrp can be calculated from multivariate statistical models taking into account the peritoneal solute transport type. Multiplication of the required DV/V by V provides an estimate of the required daily exchange volume. Maximal BSA estimates allowing a target CCrp can be calculated for each gender and peritoneal solute transport type.

Biological Transport↗
PubMed1996

Treatment of cat allergy with T-cell reactive peptides.

We induced in allergic humans the counterpart of murine experimental T-cell tolerance. T-cell lines from cat-allergic humans were used to map T-cell epitopes for the principal allergen of cat dander, Fel d 1. Two peptides of 27 amino acids each were synthesized to contain the dominant epitopes (ALLERVAX CAT). After a safety trial, we carried out a blinded study of the dose required for efficacy. We randomly divided 95 cat-sensitive patients into placebo, 7.5 micrograms, 75 micrograms, and 750 micrograms groups. Patients received a subcutaneous injection weekly for 4 wk. Before and after treatment, patients were exposed in a room inhabited by live cats and scored by nose and lung symptoms. Baseline nasal and lung scores (+/-SEM) were 6.2 +/- 0.56 and 5.4 +/- 0.73 in the 750 micrograms group; 7.8 +/- 0.53 and 4.7 +/- 0.68 in the placebo group. Six weeks after treatment, scores adjusted for baseline differences were reduced in the 750 micrograms group: -2.3 +/- 4.9 and -2.3 +/- 0.59 compared with -0.84 +/- 0.50 and -0.85 +/- 0.62 in the placebo group. The 75 micrograms group showed intermediate effects and the 7.5 micrograms group no effect. Linear trend analysis indicated a significant dose response effect: p = 0.05 for nose and 0.03 for lung symptoms. Allergic side effects occurred an hour or more after the first 750 micrograms dose in 16 of 24 patients but required little or no treatment with one exception. T-cell reactive treatment peptides safely improved allergic responses to cats.

Allergens↗
PubMed1996

Increased airway resistance due to surfactant dysfunction can be alleviated with aerosol surfactant.

To investigate the contribution of pulmonary surfactant to a low airflow resistance through narrow conducting airways, a system was developed with which it was possible to determine the resistance meeting a steady flow of air at 0.5 mL/min. The airflow, delivered by an infusion pump, entered the extreme periphery of a conducting airway in an excised rat lung and exited through the trachea. The resistance was determined by measuring the pressure of the air entering the lung. If the airway remained open, the pressure was only slightly above zero; when a blocking liquid column formed in the lumen of the airway, the pressure increased rapidly but dropped abruptly as the liquid was pushed away into a wider airway section. When endogenous pulmonary surfactant was removed with a saline lavage, the airway was blocked almost constantly by an endless re-formation of liquid columns. Consequently, during a 4-min period of pressure recording, free airflow was observed only rarely. However, administration of aerosol surfactant increased the duration of free airflow in relation to the volume administered. After an injection of 80 mL of aerosol surfactant, the airway stayed open 89 +/- 3% of the 4-min recording time compared with only 28 +/- 5% when the same volume of air (80 mL) without surfactant had passed through the airway (p < 0.0001). We conclude that surfactant contributes to a free airflow through conducting airways and may have an important role in the maintenance of low airway resistance.

Aerosols↗