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Biomedical subjects

S Singh

Publications and source records attributed to S Singh.

At least 127 records · Page 7Linked to original sources
PubMed2004

Labial talon cusp on permanent central incisor: a case report.

Talon cusp is a supernumerary crown structure, a developmental disturbance in the shape of teeth that causes various diagnostic, functional and esthetic problems. Some synonyms for talon cusp are dens evaginatus of anterior teeth, interstitial cusp, tuberculated tooth, odontoma of the axial core type, evaginated odontoma, enamel pearl, supernumerary cusp etc. The lingual location on incisors, which frequently affects occlusion, is pathognomonic of the talon cusp. This report describes a rare odontogenic, isolated anomaly rather than an integral part of any disorder, a case of talon shaped cusp projecting from the labial surface of a maxillary permanent central incisor.

Child↗
PubMed2004

The physical and chemical stability of anti-tuberculosis fixed-dose combination products under accelerated climatic conditions.

OBJECTIVE: To determine the physical and chemical stability of anti-tuberculosis fixed-dose combinations (FDC) of rifampicin (RMP), isoniazid (INH), pyrazinamide (PZA) and ethambutol (EMB) sold on the Indian market. METHODS: The products were stored for 3 months under ICH/WHO accelerated conditions (40 degrees C / 75% RH), with and without the original packaging in the presence and absence of light. RESULTS: The initial RMP, INH and PZA content was found to be within the range of 90-110% of the label claim. However, the products were found to have some chemical instability even initially; one of the tablets also showed physical instability. Under accelerated conditions, the unpackaged products underwent severe changes, whereas both physical and chemical changes were also observed in the packaged formulations. The physical changes were stronger under lighted conditions. A significant finding is that PZA and perhaps EMB may play a catalytic role in the interaction between INH and RMP. CONCLUSION: This study suggests that, unless they are packed in barrier packaging, anti-tuberculosis FDC formulations should be considered unstable, and due consideration should be given to their development pharmaceutics, packaging and stability testing.

Antitubercular Agents↗
PubMed2004

Threshold intensity and central motor conduction time in patients with monomelic amyotrophy: a transcranial magnetic stimulation evaluation.

OBJECTIVE: To determine the Cortical threshold intensity (TI) and central motor conduction time (CMCT) in patients with monomelic amyotrophy (MMA). METHODS: TI and CMCT were evaluated by means of transcranial magnetic stimulation in 18 patients of MMA and 12 healthy controls at the clinical neurophysiology laboratory, department of neurology, All India Institute of Medical Sciences, New Delhi. RESULTS: The mean age of patients was 23.6 (SD 6. 7) years and of controls was 24.3 (SD 3.2) years (p > 0. 05). The mean TI in patients was 60.83% (SD 11.28) on ipsilateral and 60% (11.5%) on contralateral cortex stimulation. In controls, the mean TI was 66.67% (SD 11.5) on one side and 65% (11.87%) on contralateral cortex stimulation. There was no significant difference in the TI between these two groups (p > 0.05). The mean CMCT in patients was 8.3 (SD 1. 7) ms on ipsilateral and 9.4 (SD 1.6) ms on contralateral cortex stimulation (p > 0.05). In controls CMCT was 8.3 (SD 1.8) ms on one side and 8.6 (SD 1.4) ms on contralateral cortex stimulation. Upper limit of normal CMCT was 12.7 ms. CONCLUSIONS: As compared to controls there was no significant abnormality in TI and CMCT was normal in all except two patients where it was marginally prolonged. This could be because of excessive loss of anterior horn cells.

Adolescent↗
PubMed2004

Hereditary opalescent dentin--a case report.

A female patient aged 6 years reported with brown coloured small sized teeth that were continuously wearing out. The teeth were badly attrited upto the gingival margins. The occlusal surfaces were flattened. The clinical and radiographical examination confirmed the case as Hereditary opalescent Dentin. The rationale for early diagnosis and treatment has been discussed.

Child↗
PubMed2004

Myasthenic crisis: a retrospective study.

BACKGROUND AND OBJECTIVE: Myasthenic crisis (MC) is one of the important and common complications in the natural history of myasthenia gravis (MG). MC can be precipitated by multiple factors including deficiency or excess of the acetylcholinesterase inhibitors (AChEI). Any episode of MC is an emergency requiring aggressive therapy. We studied the demographic, clinical and treatment-related characteristics of patients who developed MC. MATERIALS AND METHODS: A retrospective study was conducted in patients with MC admitted during a 31-month period from February 1999 to August 2001, at a tertiary care center in India. RESULTS: Eleven patients (9.69% of the total 114 patients with MG) were admitted with 12 episodes of MC. Mean age at presentation was 39.83 + 13.18 years with male predominance. Seven patients had undergone thymectomy previously; of which 2 had postoperative MC. Six patients had thymoma. Steroid or cholinesterase inhibitor withdrawal and infections were the commonest precipitating factors for MC. Patients required ventilatory support for median 14 days. They responded to low volume of plasma exchange (PE) (mean 854 ml / day with mean 6.5 cycles per patient). CONCLUSIONS: This report highlights that the subset of Indian patients with MG who are at risk to develop MC belong to the 3rd and 4th decade, have bulbar symptoms at presentation and are associated with thymoma. Patients with MC should have judicious drug adjustments under supervision and should be treated aggressively during impending MC.

Adult↗
PubMed2004

Recurrent aggressive angiomyxoma of vagina--a case report.

Aggressive angiomyxoma is a rare tumour, which presents as a painless expanding mass in the vulvo-vaginal region. It usually occurs in 2nd to 3rd decades of life. It behaves like a low-grade sarcoma with high propensity for local spread and recurrence and can involve vulva, perineum, vagina and urinary bladder. It is difficult to differentiate clinically this tumour from other mesenchymal tumours occurring in this region. Microscopically it must be differentiated from malignant tumours with myxoid change, like liposarcoma and myxoid leiomyosarcoma. Hence, histopathologic examination has a central role in diagnosis of this tumour. We are presenting a case of young woman, who came with history of swelling in vulva and perineum. Imaging studies in the perineal region revealed a large pelvic mass. Fine needle aspiration cytology was inconclusive due to scanty material. Enucleation of mass was attempted in first surgery but complete extirpation could not be performed. The swelling recurred within few weeks after surgery and required irradiation. A second surgery, however, was successful in complete removal of the tumour.

Adult↗
PubMed2004

Beta2 microglobulin as a surrogate marker for HIV infection: good correlation with CD4 counts.

To determine if beta-2 microglobulin (beta2M) levels were elevated in our HIV infected patient population and if it could be used as a surrogate marker for disease progression. Thirty-eight HIV infected individuals and 26 age and sex-matched controls were studied. Measurement of CD4 cell count was carried out on a flowcytometer using anti-human CD4 monoclonal antibody and beta2M was measured by an enzyme immunoassay. Mean levels of HIV infected individuals were 1.29 +/- 0.52 mg/L and were significantly higher than 0.74 +/- 0.07 mg/L, the value of controls (p value <0.01). There was a negative correlation between CD4 counts and beta2M levels (r-value-0.79, p value <0.001). Beta2M levels in HIV infected individuals who have no opportunistic infection are elevated and these levels correlate with the CD4 counts. Beta2M can be used for the clinical follow-up of patients with HIV infection.

Adult↗
PubMed2003

Reversal of cadmium induced oxidative stress by chelating agent, antioxidant or their combination in rat.

The influence of an antioxidant agent such as N-acetyl cysteine (NAC) or mannitol on the cadmium chelating ability of monoisoamyl 2,3-dimercaptosuccinate (MiADMS) was investigated in cadmium pre-exposed rats. This ester of 2,3-dimercaptosuccinic acid (DMSA), an accepted drug for lead poisoning, being lipophilic in nature was expected to be an efficient cadmium chelator. The treatment of cadmium intoxicated animals with MiADMS reversed cadmium induced increase in blood catalase, superoxide dismutase (SOD) and malondialdehyde (MDA), liver MDA and brain SOD and MDA levels but not the decrease in blood, liver brain reduced glutathione (GSH) and increase in oxidized glutathione (GSSG) levels, consistent with the lowering of tissue cadmium burden. The administration of NAC or mannitol reversed the cadmium induced alterations in blood and liver GSH, GSSG, blood catalase, SOD, MDA, liver SOD, MDA and brain MDA levels without lowering blood and tissue cadmium contents. However, treatments with the combination of MiADMS and NAC or MiADMS and mannitol reversed these alterations as well as reduced blood and tissue cadmium concentrations. The combined treatment with MiADMS and mannitol was better than that with MiADMS and NAC, and was significantly more effective in normalizing blood, liver GSH, GSSG, brain GSSG, and their GSH/GSSG ratios than that by either of them alone. The combined treatments also improved liver and brain endogenous zinc levels, which were decreased due to cadmium toxicity. The results suggest that the administration of an antioxidant during chelation of cadmium may provide beneficial effects by reducing oxidative stress without its cadmium removing ability.

Acetylcysteine↗
PubMed2003

HPLC and HPTLC assays for the antimalarial agents chloroquine, primaquine and bulaquine.

A combination Kit for antirelapse treatment of P. vivax malaria, consisting of Chloroquine phosphate tablets and Bulaquine capsules has been recently developed, and marketed under the trade name Aablaquine. Bulaquine is prepared from Primaquine. Several methods of analysis are reported for each drug separately as well two drugs in combination but no method for simultaneous estimation of these three drugs is known. Therefore, the present study was undertaken to develop a sensitive and reproducible high performance liquid chromatographic as well as high performance thin layer chromatographic assay method for the simultaneous estimation of Chloroquine, Primaquine and Bulaquine.

Antimalarials↗
PubMed2003

PrP Sc-like prion protein conformer in sudden infant death syndrome brain.

Nothing is known about the pathophysiology of sudden infant death syndrome (SIDS). Here we show the presence of misfolded prion protein (PrP(Sc)-like) in extracts of various sections of the brains of two SIDS victims. DNA sequence information for one of these (death at 12 days) revealed two nucleotide variants in the protein coding region of the PrP gene. This may be a key finding in the understanding of SIDS pathology, and may suggest ways for identifying risk factors for SIDS in newborn infants.

Adult↗
PubMed2003

Behaviour of the kyphotic angle in spinal tuberculosis.

We followed 70 adult patients with spinal tuberculosis for a minimum of 2 years. Forty patients were treated by ambulant multi-drug chemotherapy (group A), and 30 with neurological complications (group B) were treated by antero-lateral decompression and chemotherapy. We studied the angle of spinal kyphosis as calculated on lateral spinal X-ray by the modified Konstam's method. The angle at final follow-up was compared with the pre-treatment angle. The relationship between the amount of initial vertebral loss, the predicted kyphotic angle and the observed kyphotic angle was analysed. Mean initial vertebral loss, mean pre-treatment angle and mean observed kyphotic angle in group A were 0.77 degrees, 24.3 degrees and 31.75 degrees respectively, with a mean increase in angle of 7.4 degrees. In group B, the readings were 0.67, 25.9 degrees and 26.8 degrees respectively, with a mean increase in angle of 0.9 degrees. Kyphotic deformity continued to progress until 2 years' follow-up. Progression was more pronounced in the non-operative group.

Adolescent↗
PubMed2003

Assay method for quality control and stability studies of a new CVS disorder agent (compound 93/478).

1-[4-(4-fluorophenyl)-piperazine-1-yl]-3-(2-oxopyrrolidin-1-yl)-propane hydrochloride, (I), (CDRI code No. 93/478) is a new potent anti-ischemic and anti-hypertensive agent, being developed at the Central Drug Research Institute (CDRI), Lucknow, India. A sensitive high performance liquid chromatographic assay method has been developed and validated for in process quality control and for stability studies. HPLC separation was achieved on a C(18) Purospher (Merck) column using a gradient of 0.02% tetra-methyl ammonium hydroxide (pH 7.5) and acetonitrile as mobile phase. The eluents were monitored by diode array detector at 240 and 290 nm. The lower limit of detection of I was 0.62 microg/ml, while the lower limit of quantitation was set to be 1.5 microg/ml. The calibration curves were linear in the range 1.5-62 microg/ml. Reproducibility of the method was determined by inter and intra assay variation, which were <10%.

Calibration↗
PubMed2003

Effects of ascorbic acid on lead induced alterations of synaptic transmission and contractile features in murine dorsiflexor muscle.

Lead is a common environmental toxin that affects neuromuscular junction and potentially might cause muscle weakness. Antioxidants like ascorbic acid may protect against lead induced myopathy. The present study measured isometric twitch tensions (evoked either directly by muscle stimulation or indirectly by nerve stimulation) to study effects of ascorbic acid on lead induced alterations at murine dorsiflexor skeletal muscle. Resting membrane potentials (RMPs), endplate potentials (EPPs) and miniature endplate potentials (MEPPs) were also recorded. Forty animals were divided into four groups of n = 10 each. (10 control, 10 lead alone, 10 ascorbic acid alone, 10 lead treated plus ascorbic acid). Lead (1 mg/kg) i.p, was administered daily for 2 weeks before the recording day and ascorbic acid (200 mg/kg, i.p) was given daily for 3 weeks prior to the experiment day. Lead treatment reduced twitch tension significantly (from 4.3 +/- 0.5 g to 2.7 +/- 0.2 g) and delayed half time of decay compared to the control. Similarly MEPPs frequencies were reduced following lead treatment. Application of ascorbic acid prevented twitch tension reduction in lead treated mice (3.3 +/- 0.3 g) and reversed lead induced delay in half time of decay. The negative actions of lead treatment on MEPPs frequencies were also modified with ascorbic acid. It appears that ascorbic acid exerts a protective role against lead induced peripheral nerve and muscle dysfunction. This effect of ascorbic acid on lead induced neuromyopathy is probably mediated via a free radical scavenging mechanism or modification of Ca(2+) homeostasis.

Animals↗
PubMed2003

Antimicrobial activity of terpenoids from Trichodesma amplexicaule Roth.

T. amplexicaule Roth. has been investigated phytochemically for biologically active constituents from the benzene extract. This yielded a mixture of terpenoids: beta-sitosterol, alpha-amyrin, lupeol, hexacosanoic acid, ceryl alcohol and hexacosane. The sequential extracts, isolated terpenoids and reference antibiotics were screened for their possible bioactivities against selected pathogenic bacteria, Escherichia coli, Staphylococcus aureus and fungi, Aspergillus flavus and Penicillium chrysogenum etc. Out of the sequential extracts, the benzene extract was more potent against S. aureus (IZ = 10.36) and R. phaseoli (IZ = 10.69). The inhibition zones of isolated terpenoids were also recorded and the activity index was calculated and it was found that hexacosane was more active (IZ = 13.39) against E. coli and hexacosanoic acid had greater activity against A. flavus (IZ = 11.56). The present study deals with antimicrobial screening of sequential extracts and isolated terpenoids.

Anti-Infective Agents↗