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Biomedical subjects

V R Singh

Publications and source records attributed to V R Singh.

At least 19 recordsLinked to original sources
PubMed2002

Low-dose liposomal amphotericin B in refractory Indian visceral leishmaniasis: a multicenter study.

In this randomized, double-blind, dose-ranging, multicenter trial, 84 patients with visceral leishmaniasis refractory to antimony therapy were administered liposomal amphotericin B (AmBisome) at cumulative doses of 3.75, 7.5, and 15.0 mg/kg for 5 consecutive days. Posttreatment apparent cure and definite cure were assessed at 2 weeks and 6 months after the end of therapy, respectively. Mild to moderate infusion-related fever and rigors were seen in 29 and 44% of patients, respectively. One patient each in the 3.75- and 7.5-mg groups had detectable parasites on splenic smear at posttreatment evaluation. At 6 months' follow-up, however, 2, 1, and 1 patients relapsed in the 3.75-, 7.5-, and 15.0-mg groups, resulting in definite cure rates of 89, 93, and 97%, respectively. There was no significant difference in the cure rates of the 3 groups. Low-dose liposomal amphotericin B given for 5 days can cure most patients with Indian kala-azar.

Adolescent↗
PubMed2001

Ultrasonic characteristics of leiomyoma uteri in vitro.

Patients suffer with various abnormalities of body tissues. "Leiomyoma Uteri" is a solid tumor of uterus, one of such abnormalities. To treat such tumors, basic physical and biologic investigations are required to be carried out. In the present work, ultrasonic characterization of soft tissues, in this case, uterine tumor in vitro, are studied. A double probe through-transmission technique is used for the measurement of these propagation parameters, viz., velocity and attenuation. Other parameters like acoustic impedance, dynamic modulus of elasticity and compressibility are also determined. The average velocity and attenuation are found to be 1550 ms(-1) and 433 dBm(-1), respectively, at 3.5 MHz frequency and room temperature 28 degrees C. The present investigation is useful in tissue differentiation and tissue identification to enable the doctors to give proper treatment.

Acoustics↗
PubMed2000

Comparison of oral fluconazole and itraconazole for progressive, nonmeningeal coccidioidomycosis. A randomized, double-blind trial. Mycoses Study Group.

BACKGROUND: In previous open-label noncomparative clinical trials, both fluconazole and itraconazole were effective therapy for progressive forms of coccidioidomycosis. OBJECTIVE: To determine whether fluconazole or itraconazole is superior for treatment of nonmeningeal progressive coccidioidal infections. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: 7 treatment centers in California, Arizona, and Texas. PATIENTS: 198 patients with chronic pulmonary, soft tissue, or skeletal coccidioidal infections. INTERVENTION: Oral fluconazole, 400 mg/d, or itraconazole, 200 mg twice daily. MEASUREMENTS: After 4, 8, and 12 months, a predefined scoring system was used to assess severity of infection. Findings were compared with those at baseline. RESULTS: Overall, 50% of patients (47 of 94) and 63% of patients (61 of 97) responded to 8 months of treatment with fluconazole and itraconazole, respectively (difference, 13 percentage points [95% CI, -2 to 28 percentage points]; P = 0.08). Patients with skeletal infections responded twice as frequently to itraconazole as to fluconazole. By 12 months, 57% of patients had responded to fluconazole and 72% had responded to itraconazole (difference, 15 percentage points [CI, 0.003 to 30 percentage points]; P = 0.05). Soft tissue disease was associated with increased likelihood of response, as in previous studies. Azole drug was detected in serum specimens from all but 3 patients; however, drug concentrations were not helpful in predicting outcome. Relapse rates after discontinuation of therapy did not differ significantly between groups (28% after fluconazole treatment and 18% after itraconazole treatment). Both drugs were well tolerated. CONCLUSIONS: Neither fluconazole nor itraconazole showed statistically superior efficacy in nonmeningeal coccidioidomycosis, although there is a trend toward slightly greater efficacy with itraconazole at the doses studied.

Administration, Oral↗
PubMed2000

Ultrasonic parameters and relationship between compressive strength, microstructure of gall bladder stones.

Patients with symptomatic stones are at a great risk for complications and these complications are a major cause of morbidity. The gall bladder stones may have a complex structure and variable composition. In the present investigation stones have been grouped into three categories namely cholesterol, bilirubinate and mixed, and a correlation between the surface structure, ultrasonic parameters and compressive strength is estimated. A double-probe through-transmission technique was used for the ultrasonic parameters study, a universal testing instrument for hardness and a scanning electron microscope (SEM) for microstructure study. Gall bladder stones of mixed type with higher ultrasonic velocity, less attenuation and higher crushing strength were found to be more difficult to break in comparison to other types of stones. SEM of mixed type stones showed rough surface as compared to bilirubinate and cholesterol stones. The results obtained as well as the relationship might be useful in the design of a focussed ultrasonic 0lithotripter.

Cholelithiasis↗
PubMed1996

Coccidioidomycosis in patients infected with human immunodeficiency virus: review of 91 cases at a single institution.

We retrospectively evaluated the clinical manifestations, diagnosis, treatment, and outcome of coccidioidomycosis in 91 patients infected with human immunodeficiency virus (HIV) at a single institution. Coccidioidomycosis was the AIDS-defining illness in 37 patients. Fever and chills, weight loss, and night sweats were the most frequent symptoms. The lung was the most frequently involved organ (80%), followed by the meninges (15%). A diffuse reticulonodular infiltrate was seen in 59 patients (65%), and 13 (14%) had focal pulmonary disease; for 15 patients (16%), the chest radiograph was normal. Coccidioidal serologies were positive for 60 patients (68%), while for 23% with proven coccidioidomycosis such tests were negative Most patients were treated with systemic amphotericin B and then an oral azole. The mortality for the whole group was 60%. Patients with diffuse pulmonary disease had the highest mortality (68%), with a median duration of survival of 54 days (P < .05; 95% confidence interval, 147-175 days). The presence of diffuse pulmonary disease and a CD4 lymphocyte count of < 50/microL were independent predictors of death. In our experience, coccidioidomycosis is an important opportunistic infection that causes substantial morbidity and mortality among HIV-infected patients living in an area of endemicity.

AIDS-Related Opportunistic Infections↗
PubMed1995

Bacillus licheniformis bacteremia: five cases associated with indwelling central venous catheters.

Bacillus species are being more frequently recognized as pathogens in immunocompromised hosts or in patients with cancer and central venous catheters. Only nine cases of Bacillus licheniformis infection have been reported in the English-language literature since 1966. In a retrospective study we describe six patients and 17 episodes of B. licheniformis bacteremia over a 5-year span. All six patients had either a Hickman or a Broviac catheter in place for more than 3 months. Five of the six patients had multiple clinically significant episodes of bacteremia due to B. licheniformis. The six patients ranged in age from 4 years to 62 years. Two patients had leukemia or lymphoma and three patients had solid tumors, but only one patient was neutropenic. No deaths were related to B. licheniformis bacteremia. B. licheniformis should be considered as a potential pathogen in immunocompromised patients, especially when bacteremia is associated with the presence of long-term central venous catheters. Mortality due to B. licheniformis bacteremia is low, but recurrent bacteremia due to this organism causes significant morbidity and usually necessitates removal of the catheter.

Adolescent↗
PubMed1992

Ultrasonic study of processed milk cream and vegetable oils.

Food systems are complex and inhomogeneous in nature. Ultrasonic propagation velocity in the food systems, in this case processed milk cream and vegetable oils, is studied. Ultrasonic properties of the food systems are similar to those of complex biological tissues. The presence of vegetable oil as an adulterant in the processed milk cream is detected with the help of a double-probe-through-transmission ultrasonic technique. The present study helps to maintain quality control of various food systems, particularly with regard to their adulteration, if any.

Animals↗
PubMed1992

Ultrasonic velocity and attenuation measurement in kidney stones: correlation to constituents and hardness.

In this investigation, ultrasonic parameters of kidney stones are measured, in vitro, using a double probe ultrasonic-through-transmission technique. Due to the complex chemical structure of these stones, a large variation in the values of the ultrasonic parameters is found. A correlation between ultrasonic properties and variation in pathology of the renal calculi is also discussed.

Acoustics↗
PubMed1991

A comparative study of fracture strength, ultrasonic properties and chemical constituents of kidney stones.

Ultrasonic properties of kidney stones were studied with a double-probe-through-transmission technique, the micro hardness was studied using the Viker indentation method and the chemical composition studied using an X-ray technique. The microhardness is found to vary with chemical composition as well as ultrasonic propagation velocity. The comparative results obtained are discussed in detail.

Hardness Tests↗
PubMed1991

Piezoelectric effect in renal calculi.

The piezoelectric effect is investigated for the first time in renal calculi in vitro. The kidney stones are shaped from solid samples as well as from stones crushed into powder and pressed into tablets. Presence of alpha quartz in the renal calculi is investigated by an X-ray technique and the presence of this constituent also helps to explain the piezoelectric effect in the renal calculi. The dielectric and piezoelectric parameters are studied in detail.

Electric Conductivity↗
PubMed1991

Stress-generated electric potential in renal stones due to ultrasound [43.35.Cg, 43.80.Cs, 62.20.Dc].

The presence of renal calculi in the kidney causes discomfort and pain to the patients and so removal of such stones is thus important. These days, nonsurgical and noninvasive techniques are used for this purpose. In this laboratory, an ultrasonic kidney stone disintegrator is being developed. In order to know design parameters for such instrument, various physical and mechanical properties of renal calculi, have been studied. During the course of ultrasonic studies in kidney stones, "stress-generated electric potential" has been observed. The in vitro samples of the kidney stones were obtained from local hospitals in Delhi. The stones were sliced into a regular shape of 1 x 1 cm. An ultrasonic field at 2.5 and 5.5 MHz was applied to the samples normal incidence to one surface. On the two surfaces parallel to the ultrasonic beam, two electrodes were applied and an electric potential was measured across these electrodes. This stress-generated potential was measured with the help of an electrometer, and varied from 0.50 to 3.0 mV and 3.10 to 12.50 mV at the two frequencies, respectively. This investigation shows that the renal calculi exhibit a stress-generated electric voltage due to their piezoelectric property.

Electric Conductivity↗
PubMed1991

Dielectric properties of kidney stones as electro-ceramics.

Dielectric properties of kidney stones in processed form are studied in a frequency range of 1 kHz-10 MHz. The samples under test are in the form of discs of the stones. The dielectric properties are found to be highly dependent on the frequency, and as expected, similar to those of conventional electro-ceramics and other such bio-materials, due to presence of alpha-quartz in the calculi.

Electric Conductivity↗
PubMed1991

Loss of strength in drilled bone in orthopaedic surgery.

It is common practice in orthopaedic surgery to drill holes in bones for the placement of screws. Such holes make the bone weaker compared to an intact one. The loss of strength after drilling holes in the compact bone is studied here.

Animals↗