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Biomedical subjects

D Kumar

Publications and source records attributed to D Kumar.

At least 73 records · Page 4Linked to original sources
PubMed2003

Characterization and imaging of compositional variation in tissues.

The diffuse surface reflectance profiles of the goat's isolated heart, spleen, and adipose tissues by multiprobe laser reflectometer are measured. The normalized backscattered intensity values for adipose, heart, and spleen tissues at source-detector separation 0.2 cm, are 0.060, 0.021, and 0.003, respectively. The optical parameters of these tissues are determined by the best fit (chi2(0.99)) of their spatial profiles with that as obtained by Monte Carlo simulation by iterative procedure. As the optical parameters of these vary over a wide range, adipose and spleen tissues are treated as inhomogeneity of diameter 0.1, 0.2, or 0.3 cm, and placed inside the control (heart) tissue at different depths. Anisotropic simulation of light backscattering or photon depth distribution is significantly different for various tissues. The surface intensity profiles vary depending on the changes in tissue composition. From the horizontal scans of the subtracted images, the photon backscattering simulated images of control and combination of tissues are obtained. By analysis of peak intensity and full-width at half maximum, the type, location, and size of the tissue compositional variation are determined.

Adipose Tissue↗
PubMed2003

Endoprosthetic replacement of the proximal humerus. Long-term results.

We studied 100 patients who had undergone endoprosthetic replacement of the proximal humerus between 1976 and 1998. The outcome was assessed with regard to the survivorship of the patients, the salvaged limbs and the prostheses. Function was determined in the 47 surviving patients, of whom 30 were assessed using the Musculo-Skeletal Tumour Society (MSTS) rating scale and 38 completed the Toronto Extremity Salvage Score (TESS) questionnaire. The median age of the patients was 34 years (10 to 80). The mean follow-up period for surviving patients was nine years (2 to 20). The mean MSTS score at follow-up was 79% and the mean TESS score was 72%. The length of bone which was resected influenced the functional outcome. Abduction of the shoulder was to 45 degrees in most patients. The overall survival was 42% at ten years and that of the limb without amputation 93%. The survival of the prostheses using mechanical failure as the endpoint was 86.5% at 20 years. Endoprosthetic replacement of the proximal humerus is a predictable procedure providing reasonable function of the arm with a low rate of complications at long-term follow-up.

Activities of Daily Living↗
PubMed2003

Age specific incidence rate and pathological spectrum of oral cancer in Allahabad.

BACKGROUND: Cancer of the oral cavity is one of the commonest cancers in India. Use of smokeless tobacco (Pan masala, Zarda etc ) is on the increase in North India and specially in Uttar Pradesh. AIMS: To assess the patients characteristics and histopathological subtypes of the oral cancer in our region. SETTINGS AND DESIGN: A single institutional retrospective study of 11 years from 1990 to 2000 was designed. Data was collected year wise using the tumour registry data. MATERIAL AND METHODS: A total of 40,559 biopsies were examined in the department during 1990-2000, out of which the oral cavity constituted 759 biopsies. The data was analysed with emphasis on age, sex, risk factors, site and histology. STATISTICAL ANALYSIS: The data was analysed utilizing the Kolomogroo-Smirnov two sample test. RESULTS: A comparison of the age specific incidence rates of oral cancer during 1990-2000 in Allahabad showed that the incidence was maximum in the 50-59 years age group and squamous cell carcinoma grade I was the most prevalent type. Of the total of 759 biopsies from oral cavity, 303 malignant cases. 232 (76.57%) were males and 71 (23.43% were females with a male to female ratio of 3.27:1. The tongue was the most frequently involved site--found in 42.57% cases. On an average, 63 new cases of oral cavity per annum were detected during this period. CONCLUSIONS: Properly structured site specific data like this can augment National Cancer Registry Programme (NCRP) and is an essential indicator for the magnitude and the pattern of the cancer problem in India Urgent public health measures like public education and oral cancer awareness are required to curb this avoidable epidemic.

Age Distribution↗
PubMed2003

Image reconstruction of optical attenuation coefficient variation in biological tissues.

A procedure for non-invasive imaging of the optical attenuation coefficient variation of in vivo thick organs/tissues is developed. The laser back-scattered surface profiles at various locations of human forearm, by multi-probe reflectometer, are measured. These profiles are matched by iterative procedure, with that as obtained by Monte Carlo simulation and the corresponding values of attenuation coefficient (equal to the sum of absorption and reduced scattering coefficients) are determined. By interpolation of this data a 100 x 100 grid is constructed and after median filtering of this data a color-coded image of the variability of the optical attenuation coefficient of the forearm is obtained. These images in different subjects show variation due to change in overall tissue composition and blood pooling. This non-invasive imaging procedure may help in identifying the diseased affected regions in healthy tissues and in application of photodynamic therapy.

Diagnostic Imaging↗
PubMed2002

Mutation analysis of the MKKS gene in McKusick-Kaufman syndrome and selected Bardet-Biedl syndrome patients.

McKusick-Kaufman syndrome comprises hydrometrocolpos, polydactyly, and congenital heart defects and overlaps with Bardet-Biedl syndrome, comprising retinitis pigmentosa, polydactyly, obesity, mental retardation, and renal and genital anomalies. Bardet-Biedl syndrome is genetically heterogeneous with three cloned genes ( BBS2, BBS4, and MKKS) and at least three other known loci ( BBS1, BBS3, and BBS5). Both McKusick-Kaufman syndrome and Bardet-Biedl syndrome are inherited in an autosomal recessive pattern, and both syndromes are caused by mutations in the MKKS gene. However, mutations in MKKS are found in only 4%-11% of unselected Bardet-Biedl syndrome patients. We hypothesized that an analysis of patients with atypical Bardet-Biedl syndrome and McKusick-Kaufman syndrome (Group I; 15 probands) and patients with Bardet-Biedl syndrome who had linkage results inconsistent with linkage to the other loci (Group II; 12 probands) could increase the MKKS mutation yield. Both mutant alleles were identified in only two families in Group II. Single (heterozygous) sequence variations were found in three Group I families and in two Group II families. Combining these results with previously published data showed that only one mutant allele was detected in nearly half of all patients screened to date, suggesting that unusual mutational mechanisms or patterns of inheritance may be involved. However, sequencing of the BBS2 gene in these patients did not provide any evidence of digenic or "triallelic" inheritance. The frequency of detected mutations in MKKS in Group II patients was 24%, i.e., six times higher than the published rate for unselected BBS patients, suggesting that small-scale linkage analyses may be useful in suitable families.

Abnormalities, Multiple↗
PubMed2002

Role of selenium in reducing hypoxia-induced oxidative stress: an in vivo study.

At high altitudes, the reactive oxygen species are continuously generated as a consequence of low oxygen partial pressure (hypoxia), which causes tissue damage. The body's defence system to combat the oxidative stress (e.g., anti-oxidant enzymes, free radical scavengers such as vitamin C, vitamin E, beta-carotene, reduced glutathione and minerals such as selenium, etc.) may diminish. In the present study, the antioxidant effect of selenium (Se) in reducing the hypoxia-induced oxidative stress was evaluated by exposing male albino rats to hypoxic stress in a decompression chamber. Exposure to hypoxia resulted in an increase in malondialdehyde (MDA) levels in plasma and tissues and a concurrent decrease in blood glutathione (GSH), glutathione peroxidase (GPx), plasma protein and plasma selenium content when compared with controls. Haemoglobin concentration (Hb%), red blood corpuscles (RBC) and white blood corpuscles (WBC) count were also increased in the hypoxia-exposed group. Selenium supplementation to animals reversed the trend. There was a significant decrease (P < 0.001) in MDA and subsequent increase in plasma and tissue GSH levels. Similarly the blood and tissue GPx and plasma protein also increased significantly in the Se supplemented animals compared with control animals. The Hb%, RBC and WBC counts showed no significant difference between Se-fed and control rats. These results suggest that selenium may help in reducing the lipid peroxidation during hypoxia.

Animals↗
PubMed2002

Review article: bloating in functional bowel disorders.

Bloating is a frequently reported symptom in functional bowel disorders. It usually occurs in combination with other symptoms, but may also occur in isolation. The severity of bloating tends to worsen during the course of the day and improves overnight. Although frequently considered to be a subjective phenomenon, recent studies have shown that bloating is associated with a measurable increase in abdominal girth. The pathophysiology of bloating remains elusive, but the evidence supports a sensorimotor dysfunction of the bowel. The possible mechanisms include abnormal gas trapping, fluid retention, food intolerance and altered gut microbial flora. Further studies are needed to define the sensorimotor abnormalities associated with bloating, which might be segmental and transient rather than generalized and persistent. The lack of understanding of this symptom is paralleled by a limited availability of therapeutic options. Conventional medications used in functional bowel disorders are not helpful and may indeed worsen the symptoms. In future, new drugs with activity against serotonin and kappa receptors, or novel approaches such as the use of exclusion diets, probiotics and hypnotherapy, may prove to be useful.

Abdomen↗
PubMed2002

The sentinel lymph node in colorectal cancer - of clinical value?

Lymph node involvement is an important prognostic factor in colorectal cancer. Sentinel node status has a significant impact on the management of breast cancer and melanoma. A 'sentinel lymph node' (SLN) is defined as the first regional lymph node to receive lymph flow from the primary tumour site. An electronic literature search was performed for all articles using key words: sentinel + lymph node + colorectal + cancer. The review indicated that the sentinel node model may help understanding different aspects of tumour biology in colorectal cancer. It will provide important information about variations in lymphatic pathways and skip metastases. It may alter the management if sentinel lymph node can be assessed preoperatively with radioisotope techniques by identifying patients with micrometastases who may benefit from adjuvant therapy. Although the sentinel lymph node concept has only recently been applied to colorectal cancer, it has a great potential for management.

Journal Article↗
PubMed2002

Antibiotics increase functional abdominal symptoms.

OBJECTIVES: Data suggest that subjects with irritable bowel syndrome are more likely to report a recent course of antibiotics. This study tests the hypothesis that a course of antibiotics is a risk factor for an increase in the number of functional bowel complaints over a 4-month period in a general population sample. METHODS: We initiated a prospective case-control study in three general practices in South London. Consecutive patients aged 16-49 attending their general practitioner with non-GI complaints and given a prescription for antibiotics were invited to participate. Comparison subjects who had not had antibiotics for 1 yr were identified from the practice records by age group, gender, and previous general practitioner visits. Fifty-eight antibiotic and 65 control patients agreed to participate. Questionnaires covering demographic, GI, and psychological data were sent at recruitment and at 4 months. Seventy-four percent of subjects completed the study. The number of symptoms at follow-up compared to that at recruitment. RESULTS: Twenty of 42 antibiotic subjects (48%) versus 11/49 control subjects (22%) demonstrated one or more additional functional bowel symptoms at 4 months (unadjusted odds ratio = 3.14 [1.27-7.75]) (chi2 = 6.4, p = 0.01). Ten of 42 antibiotic subjects (24%) versus 3/49 control subjects (6%) demonstrated two or more additional functional bowel symptoms at 4 months (unadjusted odds ratio = 4.79 [1.22-18.80]) (chi2 = 5.8, p = 0.02). CONCLUSIONS: Functional bowel symptoms come and go, but subjects who are given a course of antibiotics are more than three times as likely to report more bowel symptoms 4 months later than controls.

Adolescent↗
PubMed2002

Fatigue in cholestatic liver disease--a perplexing symptom.

Fatigue is an important symptom and a quality of life determinant in patients with cholestatic liver disease. The pathogenesis of fatigue is obscure, although alterations in central neurotransmission and peripheral muscle dysfunction have been incriminated. No effective treatment is available at present. The available literature on fatigue in cholestatic liver disease is reviewed.

Cholestasis, Intrahepatic↗
PubMed2002

Adjuvant therapy of colorectal cancer: the next step forward.

Adjuvant therapy for colorectal cancer includes chemotherapy, radiotherapy and immunotherapy. It is advocated in patients who are at significant risk of developing recurrence. We review recent advances in adjuvant treatment for colorectal cancer. Although colorectal cancer is often considered as a single entity, it is being increasingly recognised that colon and rectal cancers are distinct disease groups and separate therapeutic strategies should be considered for each. In colonic cancer, 5-fluorouracil is used, with or without other agents. Both preoperative radiotherapy and postoperative chemoradiotherapy have been used in rectal cancer. The development of oral chemotherapeutic agents has been a significant step in the management of colorectal cancer, while newer agents have been introduced with good results. Targeting the immune response and genetic manipulations are being developed as innovative management strategies. Although adjuvant therapy has improved outcome in colorectal cancer, stress should be laid on identifying patients who need adjuvant therapy, permitting individualisation of treatment strategy. Apart from including survival and local recurrence as outcome measures, new therapeutic approaches should be assessed in terms of quality of life of the patient.

Antineoplastic Agents↗
PubMed2002

Rett's syndrome - a neurodevelopmental disorder: report of two cases.

Rett's syndrome (RS), a pervasive neurodevelopmental disorder, is being increasingly recognized all over the world, but there is paucity of reports from India. Due to its manifestations at any stage of development, it is important to arrive at a correct diagnosis. Two cases are presented, highlighting the need to recognize this relatively uncommon disorder and to differentiate it from various other neurodegenerative disorders.

Child, Preschool↗
PubMed2002

Role of food hypersensitivity in irritable bowel syndrome.

A significant proportion of IBS patients attribute their symptoms to adverse food reactions. Dietary elimination and re-challenge studies support the role of diet in the pathogenesis of IBS. The aetiopathogenesis of IBS is thought to be multifactorial involving an interaction between diet, infection, antibiotics and psychosocial factors. Serum IgE and IgG4 antibodies are elevated in food hypersensitivity induced atopic conditions and a similar mechanism has been postulated in IBS. Increased number of mast cells is present in the ileocaecal region of IBS patients. Once sensitized, they are capable of inducing secretory and sensorimotor abnormalities of the gut. The management of IBS is usually aimed at controlling symptoms, however, evaluation of food hypersensitivity may provide a useful adjunct in those with severe symptoms or a clear history of adverse food reaction. There are no well-established tests available but skin prick tests and food specific serum IgG4 and IgE antibodies may help in identifying the offending foods. Other options, which may be explored in individual cases, include sequential dietary exclusion, use of hypoallergenic diets, disodium cromoglycate and novel techniques such as colonoscopic allergen provocation test. Pathophysiology of hypersensitivity induced IBS has been discussed in the light of current data and a management algorithm has been proposed for managing food hypersensitivity in IBS.

Colonic Diseases, Functional↗
PubMed2002

Laser palliation of esophageal carcinoma.

OBJECTIVE: Forty-five cases of advanced esophageal carcinoma were treated with Nd:YAG laser, to relieve dysphagia. METHODS: There were 36 males (80%) and nine female (20%) patients. The mean age of the patients was 55.87 years. Thirty-nine patients (86.6%) were found to have squamous cell carcinoma. Middle third growths were found to be most common (66.6%), followed by lower third (20%) and upper third (13.3%) tumours. The mean dysphagia grade at presentation was 3.33 with all 45 patients (100%) having dysphagia. RESULTS: After three months of treatment, the mean dysphagia grade improved to 1.73 with 39 patients being able to eat at least soft or solid food. Mean number of laser sessions required was 3.3. The mean weight of the patients also increased from 45.13 Kg to 47.71 Kg. Three patients developed an esophageal perforation (6.6%), out of whom two died. No other major complication was observed. CONCLUSION: Nd:YAG laser is thus an excellent means of palliation of distressful symptom of carcinoma of esophagus with expectable morbidity and mortality.

Carcinoma, Squamous Cell↗
PubMed2002

Bronchial stenosis after blunt chest trauma.

A young boy who sustained blunt chest trauma 24 months back, presented with repeated chest infections. His chest skiagram revealed right hemithorax opaque and CT scan of thorax showed collapse of right lung. Fiberoptic bronchoscopy helped to diagnose the post-traumatic stenosis of right main bronchus. Laser resection was utilized to restore the patency.

Adolescent↗
PubMed2001

N-propargyl-2-alkynylbenzothiazolium aza-enediynes: role of the 2-alkynylbenzothiazolium functionality in DNA cleavage.

The 2-alkynylbenzothiazolium salts 3a-d incorporating an N-propargyl moiety have been prepared as aza-enediyne analogues. While these aza-enediynes are shown to be modest DNA cleavage agents, DNA cleavage was also observed with the N-methyl-2-alkynylbenzothiazolium salt 4, which lacks the aza-enediyne moiety. The structural requirements for DNA cleavage, and the correlation of DNA cleavage efficiency with the propensity of these compounds to undergo nucleophilic addition by methanol support a proposed DNA cleavage mechanism involving DNA alkylation by appropriate 2-alkynyl-substituted benzothiazolium salts.

Aza Compounds↗
PubMed2001

Evaluation of complexation of metal-mediated DNA-binding drugs to oligonucleotides via electrospray ionization mass spectrometry.

The interactions of self-complementary oligonucleotides with a group of metal-mediated DNA-binding drugs, including chromomycin A(3), mithramycin and the novel compound UK-1, were examined via electrospray ionization quadrupole ion trap mass spectrometry. Both chromomycin and mithramycin were shown to bind preferentially to GC-rich oligonucleotide duplexes in a 2:1 drug:metal ratio, while UK-1 was shown to bind in a 1:1 drug:metal stoichiometric ratio without a strong sequence preference. These trends were observed in the presence of Co(2+), Ni(2+) and Zn(2+), with the exception that chromomycin-Zn(2+) complexes were not readily observed. The binding stoichiometries as well as the sequence specificities are in agreement with literature reports for solution studies. Binding selectivities and stabilities of the complexes were also probed using electrospray ionization mass spectrometry. Both of the GC-rich oligomers 5'-GCGCGC-3' and 5'-GCGCATGCGC-3' exhibited a binding preference for chromomycin over mithramycin in the presence of Co(2+) and Ni(2+). Energy-variable collisionally activated dissociation of the complexes was employed to determine the stabilities of the complexes. The relative metal-dependent binding energies were Ni(2+) > Zn(2+) > Co(2+) for UK-1-oligomer complexes and Ni(2+) > Co(2+) for both mithramycin and chromomycin complexes.

Antineoplastic Agents↗