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Biomedical subjects

S Rastogi

Publications and source records attributed to S Rastogi.

At least 37 records · Page 2Linked to original sources
PubMed2001

The time-dose-response relationship for elicitation of contact dermatitis in isoeugenol allergic individuals.

The elicitation response in allergic contact dermatitis is dose dependent, but the time-concentration relationship for elicitation has not previously been described. In this study 27 isoeugenol-sensitive patients participated in serial dilution patch tests with isoeugenol and a double-blinded Repeated Open Application Test (ROAT) using two concentrations of isoeugenol, 0.2 and 0.05%. Seven controls without isoeugenol allergy were also included. The participants applied 3.72 +/- 1.57 (mean +/- SD) mg/cm(2) of coded isoeugenol solutions twice a day to a 3 x 3 cm(2) area on the volar aspect of the right and left arm, respectively. For each test site the applications continued until a reaction appeared or for a maximum of 28 days. The minimal criteria for a positive reaction regarded as allergic contact dermatitis was persistent erythema at the ROAT test site. All controls were negative and 16/24 (66.7%) of the included isoeugenol-sensitive subjects showed a positive ROAT to the 0.2% solution within the study period (Fisher's test, p = 0.0024). Ten of the positive patients also reacted to the 0.05% solution. The median number of days until a positive reaction to the 0.2% solution was 7 days and was 15 days for the 0.05% solution. There was a highly significant correlation between the patients' patch test threshold and the number of days until a positive ROAT. In conclusion, the time until an isoeugenol allergic individual reacts in a ROAT depends on the individual sensitivity as well as the exposure concentrations; for low concentrations of the allergen or low degree of sensitivity, the allergic contact dermatitis may develop after several weeks of exposure. Therefore, a negative ROAT after 7 days may be a false negative.

Administration, Topical↗
PubMed2001

Investigation of solid-state reactions using variable temperature X-ray powder diffractrometry. I. Aspartame hemihydrate.

PURPOSE: The object of this study was to demonstrate the applicability of variable temperature X-ray powder diffractometry (XRD) to investigate solid-state reactions using aspartame as a model compound. METHODS: Aspartame exists as a hemihydrate (ASH) under ambient conditions and converts to aspartame anhydrate (ASA) at approximately 130 degrees C. ASA on further heating to approximately 180 degrees C undergoes decomposition (intramolecular cyclization) to form a diketopiperazine derivative (DKP). The dehydration as well as the decomposition kinetics were studied isothermally at several temperatures. The unique feature of this technique is that it permits simultaneous quantification of the reactant as well as the product. RESULTS: While the dehydration of ASH appeared to follow first-order kinetics, the cyclization of ASA was a nucleation controlled process. The rate constants were obtained at various temperatures, which permitted the calculation of the activation energies of dehydration and cyclization from the Arrhenius plots. The activation energy of dehydration was also calculated according to the method described by Ng (Aust. J. Chem., 28:1169-1178, 1975) and the two values were in good agreement. CONCLUSIONS: The study demonstrates that XRD is an excellent complement to thermal analysis and provides direct information about the solid-states of various reaction phases.

Algorithms↗
PubMed2000

Randomised controlled trial of thiopental for intubation in neonates.

AIMS: To determine the effects of premedication with thiopental on heart rate, blood pressure, and oxygen saturation during semi-elective nasotracheal intubation in neonates. METHODS: A randomised, placebo controlled, non-blinded study design was used to study 30 neonates (mean birthweight 3.27 kg) requiring semi-elective nasotracheal intubation. The babies were randomly allocated to receive either 6 mg/kg of thiopental (study group) or an equivalent volume of physiological saline (control group) one minute before the start of the procedure. Six infants were intubated primarily and 24 were changed from orotracheal to a nasotracheal tube. The electrocardiogram, arterial pressure wave, and transcutaneous oxygen saturation were recorded continuously 10 minutes before, during, and 20 minutes after intubation. Minute by minute measurements of heart rate, heart rate variability, mean blood pressure (MBP) and transcutaneous oxygen saturation (SpO(2)) were computed. The differences for all of these between the baseline measurements and those made during and after intubation were determined. Differences in the measurements made in the study and the control groups were compared using Student's t test. RESULTS: During intubation, heart rate increased to a greater degree (12.0 vs -0.5 beats per minute, p < 0.03) and MBP increased to a lesser degree (-2.9 vs 4.4 mm Hg; p < 0.002) in the infants who were premedicated with thiopental. After intubation only the changes in MBP differed significantly between the two groups (-3.8 vs 4.6 mm Hg; p < 0.001). There were no significant changes in the oxygen saturation between the two groups during or after intubation. The time taken for intubation was significantly shorter in the study group (p < 0.04). CONCLUSIONS: The heart rate and blood pressure of infants who are premedicated with thiopental are maintained nearer to baseline values than those of similar infants who receive no premedication. Whether this lessening of the acute drop in the heart rate and increase in blood pressure typically seen during intubation of unmedicated infants is associated with long term advantages to the infants remains to be determined.

Birth Weight↗
PubMed2000

Detection of Chlamydia trachomatis antigen in spontaneous abortions. Is this organism a primary or secondary indicator of risk?

In order to investigate whether or not Chlamydia trachomatis infection is a risk factor for pregnancy loss, 77 spontaneous abortion patients (6-24 weeks gestation), admitted to gynaecology emergency of Safdarjang Hospital, New Delhi, India. Twenty-five pregnant women (6-16 weeks gestation) attending the same hospital for induced abortion, were included in the study. C. trachomatis antigen was detected in endometrial curretage tissue by enzyme immunoassay (EIA). The detection rate was 15.6% (12/77) among spontaneous abortion patients and 4% (1/25) among women undergoing induced abortion. There was no statistically significant association between the mean age/mean gestational age of those experiencing spontaneous abortion, with and without C. trachomatis infection (26.9 years versus 25.06 years and 11.1 weeks versus 9.6 weeks, respectively). High prevalence of C. trachomatis was found in multigravidae and parous spontaneous abortion patients, compared with that in primigravidae and nulliparous Chlamydia-negative spontaneous aborters (75.0% versus 25.0%; 66.7% versus 33.3%, respectively). The prevalence of chlamydial antigen in patients with no prior history of spontaneous abortion was 16.1% (10/62) compared with 18.1% (2/11) in women with one prior abortion. Further study is required to determine whether C. trachomatis infection is a primary or secondary indicator of risk.

Abortion, Spontaneous↗
PubMed2000

Anti-inflammatory activity of sodium pyruvate--a physiological antioxidant.

The anti-inflammatory activity of sodium pyruvate was evaluated in acute and chronic models of inflammation in rats. Oral administration of sodium pyruvate at three different dose levels of 125, 250 and 500 mg/kg body weight significantly inhibited the carrageenan induced acute paw edema in a dose dependent manner. The effect of 500 mg/kg sodium pyruvate was comparable to that of 12.5 mg/kg of standard diclofence. In Freund's adjuvant arthritis model, oral administration of sodium pyruvate at the submaximal dose of 250 mg/kg once daily upto one week before Freund's adjuvant injection and immediately by the same route on the 7th day of adjuvant injection significantly reduced the edema at 18 hours after the challenge. The treatment was continued for 14 days thereafter in two divided doses of 125 mg/kg in the morning and 125 mg/kg in the evening. Sodium pyruvate showed significant anti-inflammatory activity at the 14th day (chronic phase) also. To conclude, sodium pyruvate exhibited significant anti-inflammatory activity in both the models of inflammation which could be attributed to its antioxidant properties.

Animals↗
PubMed2000

Dietary and serum iron, body iron stores and coronary heart disease.

OBJECTIVES: To determine the role of body-iron stores as measured by serum iron, total iron binding capacity (TIBC), transferrin, ferritin and ferritin:transferrin ratio (FTR) in patients with coronary heart disease (CHD). METHODS: A case-control study was performed in 58 newly diagnosed CHD patients and 24 controls who were evaluated using clinical history, dietary history and biochemical examination. Dietary iron was determined by history; serum iron and TIBC were measured biochemically and ferritin by enzyme-linked immunoassay. Case-control comparisons were performed by non-parametric Mann-Whitney test. RESULTS: There was no significant difference in mean age, prevalence of diabetes, hypertension and smoking, and dietary intake of calories and fats in cases and controls. Dietary iron intake was 11.2 +/- 3.4 mg/day in cases and 11.3 +/- 3.8 mg/day in controls (p > 0.05). Serum fasting glucose, cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were not significantly different in cases and controls (p > 0.05). LDL/HDL ratio (4.17 +/- 1.4 vs. 4.62 +/- 2.3) and total cholesterol/HDL ratio (6.47 +/- 1.6 vs. 6.91 +/- 2.4) were also similar. In the whole study group serum iron (54.8 +/- 35.7 mcg/dl), transferrin (11.6 +/- 7.4%) and ferritin (52.4 +/- 57.8 ng/ml) levels were low. In cases as compared to controls serum iron (56.9 +/- 31 vs. 49.6 +/- 45 mcg/dl; z = 1.707, p = 0.088) and transferrin saturation (12.5 +/- 7.8 vs. 9.5 +/- 6.2%; z = 1.83, p = 0.066) were slightly more. Ferritin levels (48.8 +/- 55 vs. 60.9 +/- 64 ng/ml; z = 2.048, p = 0.040) as well as FTR (5.51 +/- 8.6 vs 7.47 +/- 6.1, z = 2.054, p = 0.040) was significantly lower in cases. CONCLUSIONS: In Indian CHD patients the body iron stores are lower as compared to controls.

Adult↗
PubMed2000

Disuse bone loss in hindquarter suspended rats: partial weightbearing, exercise and ibandronate treatment as countermeasures.

The purpose of this study was to evaluate potential countermeasures for bone loss during long-term space missions in the hindquarter suspended rat, including partial weight bearing (surrogate for artificial gravity) episodic full weight bearing (2 hour/day full weight bearing) and treatment with the third generation bisphosphonate ibandronate (Roche). Graded mechanical loading was studied by housing the animals on a novel servo controlled force plate system which permitted the titration of mechanical force at varying frequency and amplitude and different levels of weight bearing. The force plate, which forms the cage floor, is a glass platform supported by an 18" diameter speaker cone filled with expanding polyurethane foam. An infrared optical sensor attached to the speaker cone yields a voltage linearly related to vertical displacement of the glass platform. The dynamic force on the paw was computed as a product of the apparent mass of the animal on the platform at rest and the acceleration of the platform determined from the second derivative of the optical sensor output. The mass of the animal on the platform was varied by adjusting tension on the tether suspending the animal. Mechanical impact loading was titrated with the force plate resonating at different frequencies, including 3 Hz and 16 Hz.

Animals↗
PubMed1999

Leukemoid reaction in extremely low-birth-weight infants.

The objective of this paper was to determine the incidence of leukemoid reaction and to evaluate its relationship with maternal and neonatal factors in extremely low-birth-weight (ELBW) infants. The design a case-controlled retrospective study of all live-born ELBW infants (<1000 g) over a period of 2 years, from July 1994 to June 1996. A total of 60 preterm infants were born during the study period, and are included in this report. The infants who demonstrated leukemoid reaction formed the study group, while the remainder formed the control group. Leukemoid reaction was defined as a white blood cell (WBC) count > or = 50,000/mm3. The relationship between maternal and neonatal variables and WBC counts was studied. Nine of the 60 infants studied demonstrated counts >50,000/mm3, with an incidence of 15%. There was no significant association demonstrated between maternal or neonatal variables and leukemoid reaction. Patients with leukemoid reaction had a better overall survival. Leukemoid reaction in ELBW infants is a rare and recently documented phenomenon. In our study the incidence was 15%. Although many factors have been postulated as a cause of this phenomenon, we could not demonstrate any relationship between these factors and high WBC counts, including sepsis and the use of antenatal steroids, the two most likely variables. It was interesting to note that the infants who were able to mount a leukemoid response had a better chance of survival than those who did not.

Analysis of Variance↗
PubMed1999

Solid-state phase transitions of AG337, an antitumor agent.

The object of this investigation was to perform detailed solid-state characterization studies on the different solid forms of AG337 and to determine the conditions of their interconversions. Solid-state characterization was done using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hot stage microscopy, Karl Fischer titrimetry, ambient and variable temperature X-ray powder diffractometry (XRD) and TGA coupled with FTIR (TGA/FTIR). In addition to five polymorphic forms of the anhydrate (I alpha to I epsilon), a hemihydrate (C14H12N4OS.2HCl.0.5H2O, II), a monohydrate (C14H12N4OS.2HCl.H2O; III), as well as a dihydrate (C14H12N4OS.2HCl.2H2O; IV) were identified. The 'as is' anhydrate, I alpha, resisted water uptake until stored at 98% RH (room temperature), where it transformed directly to IV, II and III transformed to IV at RH values > or = 7.6 and 84% respectively. Heating II and III to 130 degrees C in the variable temperature XRD resulted in the formation of I beta and I gamma respectively. On the other hand, I delta and I epsilon were obtained when II and III were respectively stored at 60 degrees C under vacuum. Variable temperature XRD, by providing information about the solid-state as a function of temperature, assisted in the interpretation of the DSC and TGA results. TGA/FTIR provided direct evidence that the thermal events observed in the temperature ranges of 25-150 degrees C and 200-250 degrees C were due to loss of water and loss of hydrogen chloride respectively. In addition to the conventional analytical techniques such as XRD, DSC, TGA and KFT, two other techniques, (variable temperature XRD and TGA/FTIR), were very useful in these solid-state characterization studies.

Antimetabolites, Antineoplastic↗
PubMed1999

Comparative efficacy and safety of nimesulide versus piroxicam in osteoarthritis with special reference to chondroprotection.

The efficacy and tolerability profile of nimesulide was assessed in a double-blind, piroxicam-controlled trial in 49 patients with osteoarthritis of the knee joint. Nimesulide was administered orally as 100 mg twice daily, and piroxicam was administered as 20 mg orally in the morning and placebo in the evening. These patients were stratified into two groups: clinical assessment and magnetic resonance imaging evaluation of the knee. All patients were followed for 8 weeks with clinical assessment every 2 weeks; of these, 11 patients were selected for magnetic resonance imaging evaluation, and they were treated for 24 weeks. The principal efficacy parameters were improvement in osteoarthritis severity index, joint tenderness, swelling, and functional capacity of the patients. The final judgment of efficacy was made by the physician. Nimesulide improved all primary and secondary efficacy parameters with an activity comparable to piroxicam. Significant reduction in joint swelling and tenderness was observed as early as 2 weeks in the two treatment groups; however, a greater number of patients were relieved in nimesulide group. At 8 and 24 weeks, the number of patients with no joint swelling were 66.7% versus 50% and 80% versus 66.7% in the nimesulide and piroxicam groups (P <.05). Functional capacity at 8 weeks improved in 72.2% of nimesulide and 44.4% of piroxicam recipients. Mild adverse effects, mainly gastrointestinal, considered possibly related to treatment were recorded in 4 patients treated with nimesulide and in 12 patients treated with piroxicam. No significant change in the articulating cartilage of the tibiofemoral joint was observed over a 24-week period with either treatment. Nimesulide was as efficacious as piroxicam in reducing the inflammatory indices, and both drugs were equally well tolerated.

Adult↗
PubMed1999

Isoeugenol is an important contact allergen: can it be safely replaced with isoeugenyl acetate?

The prevalence of contact allergy to the fragrance mix in individuals with eczema is up to 10%. Within the mix, isoeugenol (CAS 97-54-1) is an important individual allergen. Until May 1998, the IFRA (International Fragrance Association) guidelines suggested that isoeugenol could safely be used at a level of 0.2% in consumer products. In May 1998, IFRA recommended that isoeugenol should not be used at a level that exceeds 0.02% in consumer products, but did not provide guidance on allergen substitution. An alternative to isoeugenol, based on aroma and absence of guidelines on use, is isoeugenyl acetate (CAS 93-29-8). 155 consecutive subjects were patch tested to isoeugenyl acetate (1.2%, 0.4%, 0.13% eth.) and isoeugenol 1% pet. 6 (3.9%) had an allergic reaction to 1.2% isoeugenyl acetate at D4. The reactions to the other 2 dilutions tended to be graded. 8 individuals had at least a palpable erythema by D4 to isoeugenol 1% pet. The majority of individuals allergic to isoeugenol were also intolerant of isoeugenyl acetate. Effective labelling of fragrance substances on consumer products will facilitate monitoring of exposure.

Allergens↗
PubMed1999

Tuberculosis of the foot.

In 44 patients with tuberculosis of the foot we identified five radiological patterns of lesions; cystic, rheumatoid, subperiosteal, kissing and spina ventosa. Cystic destruction had the best outcome and rheumatoid the poorest. All the patients were cured after antituberculous treatment for 18 months, and none required surgery.

Adolescent↗
PubMed1999

Production of calcium gluconate by fermentation.

Calcium gluconate production by Aspergillus niger was investigated in shake flask, rolling shaker, air-lift reactor and stirred reactor. Growth pattern of the organism and fermentation conditions determined the yield of the product. High calcium gluconate production was achieved in air-lift reactor with pellet form of cell growth at moderate specific growth rate and biomass concentration. In another variation of air-lift reactor, when calcium carbonate was confined to a cellulose membrane, calcium gluconate production was maximum (149 g/L). At higher specific growth rate, obtained in shake flask, despite the formation of cell pellets, product formation was low. Physical separation of particulate calcium carbonate and growing cells favoured product formation. In stirred reactor pulpy mycelial growth was obtained and calcium gluconate production was poor.

Aspergillus niger↗
PubMed1999

Chlamydia trachomatis infection in pregnancy: risk factor for an adverse outcome.

A cohort of 122 pregnant women attending the hospital antenatal clinic in northern India were studied to determine the prevalence of genital chlamydial infection, and any adverse effect on the pregnancy. Endocervical swabs were taken at > 12 weeks of pregnancy and cultured for Chlamydia trachomatis. Twenty-six (21.3%) pregnant women were found to be infected with C. trachomatis. The mean age, gravidity and parity were significantly higher (25.03 vs 23.6 years, 1.88 vs 1.72 and 0.92 vs 0.68 respectively [P < 0.005]) in women from whom C. trachomatis was isolated. Follow-up was possible in 87 women who delivered in the hospital. There was increased incidence of still-birth, prematurity and low birth-weight in the C. trachomatis-positive women (16.6% vs 5.7%, 26.6% vs 18.4% and 26.6% vs 23.0%), and these differences were statistically significant (P < 0.5, P < 0.5 and P < 0.05 respectively). The results suggest a definite need for C. trachomatis screening on a wider scale, both in different risk groups of asymptomatic antenatal women and in neonates, to confirm these findings.

Adolescent↗
PubMed1998

Chain Mobility in Polymer Systems: On the Borderline between Solid and Melt. 2. Crystal Size Influence in Phase Transition and Sintering of Ultrahigh Molecular Weight Polyethylene via the Mobile Hexagonal Phase.

Polymorphism is a well-established phenomenon in crystalline materials and is important for pharmaceutical and polymeric materials. In our study concerning the processability of polymers, we came across an unusual observation related to polymorphism induced by pressure. The experimental observation is that polyethylene crystals transform from the stable orthorhombic crystal into a transient hexagonal phase. The occurrence of a transient hexagonal phase is shown to be dependent on the polymer crystal size; smaller crystals transform into the transient hexagonal phase at temperatures and pressures much below the thermodynamic critical point Qo, which is located at P = 3.6 kbar and T = 230 degreesC. The crystal size dependence in the phase transition was investigated by in situ X-ray studies in the unirradiated and irradiated solution-crystallized films. Since the chain mobility is rather high in the hexagonal phase, sintering has been attempted via this transient phase using ultrahigh molecular weight polyethylene (UHMW-PE) as a model system. UHMW-PE is an intractable polymer due to its high molar mass but possesses excellent abrasion resistance properties. For this reason it is used as an inlay in demanding applications such as artificial hip and knee joints. The service life of UHMW-PE in these artificial joints, however, is limited due to the poor processing characteristics notably during sintering, and often a second operation is needed to replace the UHMW-PE interface. Sintering via the transient hexagonal phase could provide a solution for this important problem which concerns an increasing number of people.

Journal Article↗