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Biomedical subjects

R R Rao

Publications and source records attributed to R R Rao.

At least 19 recordsLinked to original sources
PubMed2001

Correction of limb-length inequality during total hip arthroplasty.

Although several methods of intraoperative limb-length measurements have been described, their success in predicting the limb-length correction is not well documented. A new technique of measuring intraoperative limb lengthening using a vertical Steinmann pin at the infracotyloid groove of the acetabulum was studied in 100 consecutive primary total hip arthroplasties. Correlation of the predicted intraoperative correction was done with the postoperative radiographic measurements. Preoperative limb-length inequality ranged from -24 mm (short) to +2 mm (long) (mean, -4.2 mm). Intraoperative measurement of lengthening ranged from 0 to 15 mm (mean, 5.9 mm). Radiographic measurements of postoperative radiographs showed lengthening ranging from 0 to 17 mm (mean, 7.4 mm). There was significant correlation between the 2 values (r =.84). Postoperative limb-length inequality ranged from -7 mm to +8 mm (mean, 1.9 mm). None of the patients had to use shoe lifts for equalization of limb lengths.

Acetabulum↗
PubMed2000

Simultaneous regulation of hemodynamic and anesthetic states: a simulation study.

A model predictive control strategy to simultaneously regulate hemodynamic and anesthetic variables in critical care patients is presented. A nonlinear canine circulatory model, which has been used to study the effect of inotropic and vasoactive drugs on hemodynamic variables, has been extended to include propofol pharmacokinetics and pharmacodynamics. Propofol blood concentration is used as a measure for depth of anesthesia. The simulation model is used to design and test the control strategy. The optimization-based model predictive control strategy assures that constraints imposed on the drug infusion rates are met. The physician always remains "in the loop" and serves as the "primary controller" by making propofol blood concentration setpoint changes based on observations about anesthetic depth. Results are shown for three simulated cases: (i) congestive heart failure, (ii) postcoronary artery bypass, and (iii) acute changes in hemodynamic variables.

Anesthesia↗
PubMed1998

Immediate weightbearing after uncemented total hip arthroplasty.

Radiographic subsidence of the femoral prosthesis and clinical results after unilateral and simultaneous bilateral uncemented total hip arthroplasty were compared. Patients who had bilateral total hip arthroplasty began weight-bearing as tolerated on both lower extremities the day after surgery. Patients who had undergone unilateral total hip arthroplasty were maintained at 10% weightbearing on the operative limb for 6 weeks after surgery. Patients in both groups were matched for age, gender, and weight. Minimal followup was 2 years. There was no difference between the two groups in terms of clinical results. Radiographic assessments were performed immediately after surgery, 6 weeks after surgery, and again at 2 years after surgery. Radiographs were reviewed by a single observer and analyzed with a digitized data recorder. Increased subsidence of the femoral prosthesis within the bilateral group was found at 6 weeks. The mean subsidence of the femoral prosthesis at 6 weeks for the bilateral total hip arthroplasty group was 0.86 mm (range, 0.18-2.60 mm) and for the unilateral group was 0.39 mm (range, 0.07-1.46 mm). However, subsidence occurring between 6 weeks and 2 years averaged 0.50 mm (range, 0.09-1.10 mm) for the bilateral group and 0.54 mm (range, 0.03-0.99 mm) for the unilateral group. This difference was not significant. At the 2-year followup, all femoral prostheses in both groups appeared radiographically stable with evidence of bone ingrowth and no indications of loosening. Thus, immediate weightbearing after bilateral total hip arthroplasty in this study resulted in more initial subsidence (during the first 6 weeks after surgery) of the femoral prosthesis but did not preclude the prosthesis from becoming stable and achieving bone ingrowth. Patients in both groups obtained satisfactory clinical results. Because initial stability and bone ingrowth are factors influenced by prosthesis design, the results of this study may not be applicable to all implants.

Adult↗
PubMed1997

Solid state synthesis and thermal stability of HAP and HAP - beta-TCP composite ceramic powders.

Powders of pure beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HAP) and a biphasic composite mixture of HAP+beta-TCP were prepared by solid state reaction between two commercially available calcium-based precursors namely, tricalcium phosphate (TCP) and calcium hydroxide (Ca(OH)2). These reactants mixed in the molar ratios ranging from 3 : 0 to 3 : 4 (designated T0 to T4) in deionized water, milled and slip-cast into discs were heat treated in the temperature range of 600 degrees C to 1250 degrees C. The products formed were characterized by X-ray diffraction (XRD) and i.r. spectroscopic techniques for identification of phases formed and functional groups present in them. While tricalcium phosphate and calcium hydroxide taken in the molar ratio of 3 : 2 and 3 : 3 resulted in pure HAP when heat treated at 1000 degrees C for 8 h, the 3 : 1 and 3 : 1.5 molar ratio compositions resulted in a biphasic mixture of HAP+beta-TCP for similar heat treatments. Heat treatment of 3 : 4 molar ratio composition of tricalcium phosphate and calcium hydroxide at 1000 degrees C yielded HAP with free CaO as the secondary phase. Products of heat treatment at higher temperatures (1150 and 1250 degrees C) for even shorter duration (2 h) while not differing from the products obtained from T0 and T2 cases at 1000 degrees C (pure beta-TCP and pure HAP), change in the case of T1, T1.5, T3 and T4 to products with lesser percentages of HAP containing beta-TCP (in the case of T1 and T1.5) or CaO (in the case of T3 and T4) as the secondary phase.

Journal Article↗
PubMed1995

Pilot study of labelling bovine muscle tissue with 14C.

A pilot study has been performed to assess the feasibility of labelling bovine muscle tissue with 14C, in order to produce material suitable for intercomparison exercises. Approximately 1 kg of tissue was prepared by grinding, blending, labelling with 14C-methylated bovine haemoglobin and thoroughly mixing by repeated blending. The product was sealed in cans and sterilized to preserve it. Portions of raw material were dried to test the homogeneity of moisture content. Homogeneity of 14C in the natural and labelled materials was tested by analyzing sub-samples of 2-3 g in weight of the freeze-dried materials. The 14C content was determined by combusting and collecting the CO2 for liquid scintillation counting. The material was found to be homogeneous to the extent of 2-4% (R.S.D.), which is comparable with the R.S.D. of the 14C measurements. The 14C concentration in the labelled material was 8190 +/- 220 Bq.kg-1 of carbon. It was concluded that bovine muscle prepared in this manner would be suitable for intercomparison exercises. The 14C level in unlabelled tissue was found to be 260 +/- 7 Bq.kg-1 of carbon, which is similar to the level of 14C previously determined in milk and both are consistent with levels measured in vegetation in Eastern Ontario.

Animals↗
PubMed1994

Integrated approach to the management of patients with advanced germ cell tumors of the testis.

Between 1985 and 1991, 63 patients with disseminated germ cell tumors of the testis were treated with initial cisplatin based combination chemotherapy. Complete response was seen in 38% of patients. Adjunctive surgical resection of residual disease was carried out in 26 patients (41%), including the use of intraoperative radiation therapy in two patients with seminoma. Furthermore, two other patients with seminoma and residual mass underwent retroperitoneal irradiation. Salvage chemotherapy was administered to five patients with progressive disease, and only one of these could be salvaged with adjunctive surgery. A disease-free state was achieved in 75% of patients at a mean follow-up period of 30 months.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Determination of nanogram amounts of iodine in foods by radiochemical neutron activation analysis.

Three different neutron activation analysis methods have been developed for the determination of ppb levels of iodine in food samples. The methods are based on the separation of iodine using (i) toluene extraction followed by bismuth sulfide coprecipitation; (ii) bismuth sulfide coprecipitation followed by radiochemical purification with palladium iodide; and (iii) radiochemical isolation by bismuth sulfide coprecipitation. The accuracy of these methods was evaluated by analysing replicate samples of reference materials. The measured values of iodine in A-11 Milk Powder, H-4 Animal Muscle and H-9 Mixed Human Diet from the International Atomic Energy Agency (IAEA) are statistically indistinguishable from the IAEA recommended values, and those for the Standard Reference Materials 1571 Orchard Leaves and 1577 Bovine Liver from the National Institute of Standards and Technology (NIST) are in good agreement with the NIST information values. The precision, in terms of relative standard deviation, is 5% at 50-100 ppb and 10% at 5-20 ppb levels of iodine. The absolute detection limits of these methods vary between 0.5 and 10 ng of iodine. All three methods were used to measure the iodine content of several food samples. The method involving bismuth sulfide coprecipitation followed by radiochemical purification provides the best detection limit and highest precision.

Food Analysis↗
PubMed1993

Bacteriology of brain abscess--observations on 50 cases.

The bacteriology of brain abscess is complex--both aerobic and anaerobic organisms are involved, and their incidence varies from centre to centre. In this study of 50 consecutive cases of brain abscess, the value of both modern imaging techniques and the time-honoured Gram's stain was demonstrated. The Gram's stain showed organisms in 41 cases (82%) and culture was positive in 44 cases (88%). Thirty cultures yielded pure aerobic growth: Staphylococcus aureus, beta-haemolytic streptococci and Proteus spp. were predominant. Five cases gave mixed aerobic cultures, and in seven cases anaerobes were isolated. Of these, three showed a mixed aerobic and anaerobic flora. Mycobacterium tuberculosis was cultured from one of the samples, which had shown acid-fast bacilli on direct smear. M. fortuitum was cultured from one sample, although no organisms were seen in the gram-stained preparation.

Adolescent↗
PubMed1993

Zygomycotic necrotizing fasciitis caused by Apophysomyces elegans.

A case of necrotizing fasciitis of the anterior abdominal wall caused by the zygomycete Apophysomyces elegans in a healthy male following inguinal herniorrhaphy is reported. The portal of entry of the fungus into the incised skin and subcutaneous tissues was probably through either contaminated surgical sutures or postoperative surgical dressings. Broad, aseptate fungal hyphae were seen in the necrosed tissues with an associated necrotizing vasculitis. Extensive tissue debridements and a low dose of amphotericin B were not successful in controlling the rapid invasion of the tissues by the fungus.

Adult↗
PubMed1993

Clinicomycological study of candidiasis.

Opportunistic pathogens like candida are responsible for a major cause of morbidity and mortality in the chronically debilitated and the immunocompromised patient. The clinical data of 100 patients from whom candida species were repeatedly isolated were analysed. Most of the patients (40%) were above 51 years. Postoperative patients (34%) and patients with diabetes mellitus (30%) had a high incidence of candidiasis. All these patients had either long standing indwelling catheters or were on prolonged antibiotics, steroids or cytotoxic drugs as a part of the management for the underlying cause. Candida albicans (38.9%) and Candida stellatoidea (37.1%) were the most common species isolated. Maximum isolation was from urine (140) mostly obtained from patients with indwelling urinary catheters for more than a week or so. None received antifungal therapy except four, two of them died in spite of appropriate antifungal therapy.

Adolescent↗
PubMed1992

Serum adenosine deaminase activity in bacillary or paucibacillary pulmonary tuberculosis.

Serum Adenosine Deaminase (ADA) enzyme levels were estimated in 61 patients with symptoms and signs suggestive of Pulmonary Tuberculosis and correlated with "Gold standards" such as smear positivity of sputum for Acid Fast bacilli, Tuberculin skin testing and Radiological evidence. The mean ADA levels in smear and Tuberculin negative patients was 13.13 +/- 5.97 u/L, while in those with smear and/or strongly positive Tuberculin reaction, the mean levels of ADA were 33.52 +/- 15.22 u/L. The mean serum ADA levels in 25 healthy voluntary donors with no evidence of active or old Tuberculous lesion, were found to be 16.5 +/- 3.18 u/L. The specificity, sensitivity, positive predictive value and negative predictive value of the test was found to be 87%, 71%, 90% and 66.5% respectively. The results conclude that the serum ADA value is sufficiently useful in identifying those patients in whom the diagnosis of Pulmonary Tuberculosis should be actively considered.

Adenosine Deaminase↗
PubMed1991

Microwave acid digestion and preconcentration neutron activation analysis of biological and diet samples for iodine.

A simple preconcentration neutron activation analysis (PNAA) method has been developed for the determination of low levels of iodine in biological and nutritional materials. The method involves dissolution of the samples by microwave digestion in the presence of acids in closed Teflon bombs and preconcentration of total iodine, after reduction to iodide with hydrazine sulfate, by coprecipitation with bismuth sulfide. The effects of different factors such as acidity, time for complete precipitation, and concentrations of bismuth, sulfide, and diverse ions on the quantitative recovery of iodide have been studied. The absolute detection limit of the PNAA method is 5 ng of iodine. Precision of measurement, expressed in terms of relative standard deviation, is about 5% at 100 ppb and 10% at 20 ppb levels of iodine. The PNAA method has been applied to several biological reference materials and total diet samples.

Food Analysis↗
PubMed1991

Lipid profile studies in long term thiazide treated hypertensives.

Serum cholesterol and its subfractions were estimated in 23 patients on thiazide diuretics, for treatment of mild hypertension, for at least 30 months. The results were compared with those obtained in a matched set of 25 untreated mild hypertensives. It was found that while there was no difference in the level of total cholesterol, the LDL-cholesterol was significantly lower and HDL-cholesterol significantly higher in the treated group. It was also found that the total:LDL-cholesterol ratio was more in the treated group and the total:HDL-cholesterol ratio was less in the treated group. These findings suggest that coronary risk attributable to cholesterol and its subfractions does not seem to operate in long term thiazide treated patients.

Aged↗
PubMed1991

Hepatitis B surface antigen--3 years experience.

Epidemiological surveillance of Hepatitis B surface antigen in the city of Hyderabad at our Institute shows that the incidence of HBsAg is considerably high among the general population. In a comparative evaluation of the two techniques used, RPHA and ELISA, the latter emerged as a reliable one with high specificity and sensitivity. Screening of all blood samples by ELISA is imperative for uniform reporting of the incidence. Non risk groups like voluntary blood donors, cardiac patients serve as potential reservoirs of HBV infection.

Carrier State↗