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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 613 records · Page 34Linked to original sources
PubMed1999

Neuroanatomic substrates of late-life mental disorders.

Advances in magnetic resonance imaging (MRI) techniques have made it possible to quantify anatomic brain abnormalities in neuropsychiatric disorders. This review focuses on controlled, quantitative MRI studies in depression, degenerative disorders, and psychosis in the elderly. Although many of the anatomic abnormalities detected are observed across disorders, the patterns of regional involvement may be more selective and disorder specific. We integrate MRI findings with relevant clinical and neurobiologic observations in an attempt to develop a cohesive model of late-life psychiatric illness. Although the model primarily alludes to the pathophysiology of late-life depression, it may have broader biologic implications for other mental disorders in the elderly.

Age of Onset↗
PubMed1999

Mucoid cystic degeneration of the cruciate ligament.

A 35-year-old man was seen with pain in the back of the knee. MRI showed a mass in the anterior cruciate ligament. Biopsy indicated mucoid degeneration. Arthroscopic resection of the ligament was carried out, with relief of symptoms.

Adult↗
PubMed1999

Relationships between topoisomerase II inhibition, sequence-specificity and DNA binding mode of dicationic diphenylfuran derivatives.

Four diphenylfuran derivatives possessing different dicationic terminal side chains were used to investigate sequence-specific binding to DNA and poisoning of human topoisomerase II. Footprinting experiments with a range of DNA substrates attest that all four drugs bind selectively to AT-rich sequences in DNA. However, the quantitative analysis of the footprinting profiles reveals significant differences in terms of AT-selectivity according to the nature of the basic side chains. Furimidazoline (DB60) shows a reduced capacity to interact selectively with A.T tetrads compared with furamidine (DB75) and the 3-pentyl-substituted diamidine analogue DB226. DB244, for which the two amidine ends are substituted with a cyclopentyl group, exhibits the most pronounced AT specificity. It binds tightly to sites composed of at least four adjacent AT base pairs, such as 5'-TAAT, AATT and TTTT. At low concentrations (< 2 microM) DB60 is also capable of forming stable complexes with AT sites but at higher concentrations the binding becomes totally non-specific due to additional intercalation of drug molecules into GC-rich sequences. Nevertheless, DB60 is the only drug is the series which stabilizes DNA-topoisomerase II covalent complexes. This compound effectively promotes DNA cleavage by topoisomerase II whereas DB75, DB226 and DB244 have practically no effect. The topoisomerase II poisoning activity of DB60 correlates with its ability to intercalate into GC sites in DNA whereas the three other diphenylfurans essentially behave as typical AT-selective minor groove binders. The study suggests that the antimicrobial activity of the diphenylfurans, which are active against the Pneumocystis carinii pathogen (PCP), depends essentially on their capacity to recognize AT-rich DNA sequences rather than their ability to interfere with topoisomerase II. In contrast, the cytotoxicity of drugs like DB60 would be connected with the formation of intercalation complexes and the stimulation of DNA cleavage by human topoisomerase II.

Anti-Bacterial Agents↗
PubMed1999

Critical role of p42/44(MAPK) activation in anisomycin and hepatocyte growth factor-induced LDL receptor expression: activation of Raf-1/Mek-1/p42/44(MAPK) cascade alone is sufficient to induce LDL receptor expression.

The protein synthesis inhibitor anisomycin activates stress-related mitogen-activated protein kinases (MAPKs), namely, c-jun NH(2)-terminal kinase (p46/54(JNK)) and p38(MAPK) in mammalian cells. In this paper, we show that although exposure to anisomycin resulted in rapid and strong activation of p46/54(JNK) and p38(MAPK), with a delayed low level dual-phosphorylation of mitogen/extracellular protein kinase (p42/44(MAPK)), low density lipoprotein (LDL) receptor induction depends solely on the mild activation of p42/44(MAPK) signaling cascade in HepG2 cells. Unlike hepatocyte growth factor (HGF) which caused LDL receptor induction via rapid, strong, and Ras-dependent p42/44(MAPK) activation, anisomycin-induced p42/44(MAPK) activity and increased LDL receptor expression in a Ras-independent manner. Finally, we examined the role of the p42/44(MAPK) signaling cascade in LDL receptor induction by activating this kinase independently of anisomycin or HGF. By using estrogen-dependent human Raf-1 protein kinase in transient transfection assays, we show that the exclusive activation of the Raf-1/MEK-1/p42/44(MAPK) signaling cascade with antiestrogen ICI 182, 780 caused induction of LDL receptor expression to the same level as observed with either HGF or anisomycin. Consistent with the role of p42/44(MAPK), induction was strongly inhibited by pretreatment with the MEK-1/2 inhibitor PD98059. Our observation that anisomycin can use p42/44(MAPK) signaling cascade is a departure from established thinking, and the results presented shows that activation of the p42/44(MAPK) alone is sufficient to fully induce LDL receptor transcription.

Anisomycin↗
PubMed1999

Lipid-rich follicular carcinoma of the thyroid in a patient with McCune-Albright syndrome.

A 41-year-old woman with McCune-Albright syndrome and a 2-cm thyroid nodule of ten years' duration presented for fine-needle aspiration, which yielded vacuolated clear cells with granular chromatin in pseudopapillary arrangement. The resected tumor showed 90% clear cells and 10% nonclear cells with capsular and vascular invasion. The cytoplasmic vacuoles in the clear cells were 3+ for oil red O stain in touch imprint cytology. Immunohistochemistry demonstrated thyroglobulin positivity in the nonclear neoplastic cells, whereas most of the clear cells were negative. Ultrastructural study demonstrated the gradual transition from protein synthesis to lipid synthesis as the neoplastic cells progressed from nonclear to clear. The study suggested that the lipid accumulation resulted from the uncontrolled fatty acid synthesis in the neoplastic cells rather than metaplasia. The karyotype of the tumor cells was normal, 46XX. Literature of lipid-rich thyroid neoplasms were reviewed.

Adenocarcinoma, Clear Cell↗
PubMed1999

Immobilization of cholesterol oxidase on Formvar using organic solvents.

The present study describes a new immobilization support for the preparation of enzyme membrane in the presence of organic solvents. The support was composed of Formvar solubilization in organic solvents with enzyme. More than 90% of the enzyme was immobilized on the membrane. The membrane was prepared by mixing 4% Formvar in organic solvents and 1% cholesterol oxidase was immobilized by entrapment technique. Practically no leaching of the entrapped enzyme was observed. The resultant immobilized enzyme membrane was stored at 4 degrees C for 10 days without losing its activity. The pH and temperature stabilities were greater than those of the native enzyme. The immobilized enzyme membrane has a long life due to its hydrophobic nature, as compared with other membranes.

Cholesterol Oxidase↗
PubMed1999

Surgical complications of cochlear implantation: a report of three cases and their clinical features.

The most common complications of cochlear implantation are flap necrosis, compressed or improperly placed electrodes, and facial nerve injury, paresis, or stimulation. We report on three recent complications experienced at our institution: 1) a flap ischemia and partial-thickness necrosis without infection or device exposure, 2) facial nerve stimulation, which was managed with a new programming technique, and 3) a postimplant cholesteatoma in a patient with chronic eustachian tube dysfunction that required reoperation and explanation. We discuss the pathophysiology, likely etiology, and recommendations for management of these complications.

Aged↗
PubMed1999

Cyclosporine trough levels in renal graft recipients.

Blood Trough Levels (TL) of cyclosporine (CyA) [the drug panimun bioral cyclosporine oral solution USP--modified. Panacea Biotec Ltd], were monitored in 103 renal transplant patients who were receiving CyA orally. Two hundred and sixty-two blood concentrations of CyA were determined using a validated HPLC assay over a period of two years. Mean dose from week 1 until 2 years ranged from 7.65 +/- 0.9 to 2.73 +/- 0.8 mg/kg. Mean blood CyA levels ranged from 197.4 +/- 87.5 to 205.9 +/- 113.5. The TL concentration changes versus dose reduction were not markedly different after 2-4 weeks and remained within therapeutic range. Stabilised concentrations were achieved after first month. We conclude that the blood TL of CyA were in the nominal therapeutic range suitable for renal transplant patients.

Cyclosporine↗
PubMed1999

Effect of helium-neon laser on wound healing.

To estimate the biostimulatory effects of low intensity laser radiation on healing of skin wounds, two linear skin wounds were produced on either side of dorsal midline in rats and immediately sutured. Wounds on the left side were irradiated daily with helium neon laser at 4 Joules/sq.cm for 5 min., while those on right side were not exposed and served as controls. The mean time required for complete closure in control group was 7 days while irradiated test wounds took only 5 days to heal (P < 0.01). The mean breaking strength, as measured by the ability of the wound to resist rupture against force, was found to be significantly increased in the test group. Early epithelization, increased fibroblastic reaction, leucocytic infiltration and neovascularization were seen in the laser irradiated wounds. The results establish the biostimulatory effects of low intensity laser radiation on healing of skin wounds.

Animals↗
PubMed1999

Is spinal anaesthesia safe in pre-eclamptic toxaemia patients?

Thirty-three patients of pre-eclamptic toxaemia underwent caesarean section (CS) under general anaesthesia (n = 16) and spinal anaesthesia (n = 17). The Apgar score at 1, 5 and 10 minutes of the babies following spinal anaesthesia (SA) were only marginally better than that of general anaesthesia (GA; P > 0.05). The incidence of complication following GA (68.8%) were significantly (P < 0.05) more than that of SA (47.1%). Commonest complications following GA were intra-operative hypertension (68.8%) followed by difficult intubation (25%), pulmonary oedema (12.8%), delayed recovery (12.8%) and mortality (4.3%). While following SA complications were intra-operative hypotension (47.1%), difficult SA (29.4%) and intra-operative vomiting (5.9%). The nature of complications following GA were more serious which may even lead to mortality (4.3%), whereas following SA it was less serious and easily manageable. Hence SA is not as unsafe as it is thought.

Anesthesia, General↗
PubMed1999

Glutathione level and its relation to radiation therapy in patients with cancer of uterine cervix.

Glutathione functions as an important antioxidant in the destruction of hydrogen peroxide and lipid peroxides by providing substrate for the glutathione peroxidase and also promotes the ascorbic acid. Glutathione plays a vital role in detoxification of xenobiotics, carcinogens, free radicals and maintenance of immune functions. The study was aimed to determine plasma glutathione as well as erythrocyte glutathione and glutathione peroxidase in patients with invasive cervical carcinoma (n = 30) before initiation and after completion of radiotherapy and subsequently, at the time of first three monthly follow-up visit. The levels of plasma glutathione, erythrocyte glutathione and glutathione peroxidase activity were found to be lower in all cervical cancer patients as compared to age matched normal control women. The study indicates a change in antioxidant status in relation with the glutathione system among patients with invasive carcinoma of the uterine cervix. This study also demonstrates the effect of radiation therapy on this antioxidant system.

Adult↗
PubMed1999

Anti-C1q antibody as a marker of disease activity in systemic lupus erythematosus.

The present study was conducted to examine the usefulness of anti-C1q antibody as a marker of disease activity in Indian patients with systemic lupus erythematosus (SLE). We standardized the assay for detection of IgG anti-C1q antibody using ELISA. The normal cut-off level was determined by testing 57 healthy, age and sex matched controls to be 53 units/m1 (mean +/- 2 SD). Patients with SEL (97 females and 13 males) were studied and the following parameters were obtained on all: SLE disease activity index (SLEDAI), anti-C1q, anti-ds DNA and C3. Correlations were tested between these parameters using Spearman's rank correlation coefficients. Anti-C1q was found positive in 66 (60%) patients while anti-ds DNA was found in 78 (71%). The positive predictive values of anti-C1q and anti-ds DNA for lupus nephritis were 59 and 61 per cent respectively. The titres of anti-C1q correlated positively with SLEDAI (P < 0.01) and anti-ds DNA (P < 0.01) and negatively with C3 levels (P < 0.001). No significant correlation was observed between anti-C1q positivity and any particular organ involvement. Similarly, no correlation was found between anti-C1q and proliferative lupus nephritis. Anti-C1q was found positive in 5 of 9 patients with moderate SLEDAI scores and negative for anti-ds DNA antibody. It is concluded that anti-C1q antibody can serve as a general marker for lupus activity, supplementing the currently used serum markers.

Adolescent↗
PubMed1999

Widespread outbreaks of measles in rural Uttar Pradesh, India, 1996: high risk areas and groups.

OBJECTIVE: To describe outbreaks of measles which affected many districts in Uttar Pradesh (UP) during 1996. DESIGN: Outbreak investigations. SETTING: The state of Uttar Pradesh, India. METHODS: The reported data on measles morbidity, mortality and vaccine coverage from 1991 through 1996 were reviewed. Reported vaccine coverage levels were compared with the results of coverage surveys carried out in UP from 1992 through 1996. Line lists on measles cases were analyzed to ascertain the age, immunization status, geographical distribution, and age and sex-specific fatality ratios during the outbreaks. A community survey was organized in 7 affected villages to estimate vaccine effectiveness. RESULTS: Fifty one of 68 districts in UP reported 6922 measles cases and 281 deaths in 1996. The majority of cases and deaths occurred in June and July which are usually low transmission months. Overall cases fatality ratio (CFR) was 4.1%. CFRs were significantly higher in females and young children. The median age of cases was found to be below 5 years. There was heavy clustering of cases and deaths in rural areas. About 85% of the cases and virtually all the measles associated deaths occurred in unvaccinated children. Published documents on statewide coverage surveys revealed that the measles vaccine coverage levels ranged between 26% and 36% during 1992-96. Large gaps were found between reported coverage and survey results. Nevertheless, epidemiological studies indicated a vaccine effectiveness of more than 90%. CONCLUSIONS: The outbreaks occurred due to poor vaccine coverage levels and an inefficient surveillance system which failed to generate early warning signals. The study highlights the urgent need to raise the vaccine coverage levels rapidly in all districts to achieve measles control and prevent future outbreaks in UP.

Age Distribution↗