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Biomedical subjects

Rajeev Kumar

Publications and source records attributed to Rajeev Kumar.

At least 37 records · Page 2Linked to original sources
PubMed2006

Early patency rates after the two-suture invagination technique of vaso-epididymal anastomosis for idiopathic obstruction.

OBJECTIVES: To prospectively evaluate the results of vaso-epididymostomy, using a two-suture microsurgical invagination technique, when used for men with azoospermia due to an obstruction at the vaso-epididymal junction. PATIENTS AND METHODS: Between December 2002 and November 2004, 29 men with idiopathic obstructive azoospermia underwent vaso-epididymostomy with the two-suture invagination technique. The patency rate was assessed by return of sperm in the semen after surgery. RESULTS: In all, 23 men provided at least one postoperative semen sample. The mean (range) follow-up was 7.6 (1.5-30) months. In 11 of these men (48%), patency was shown at a mean of 3.2 (1.5-7) months after surgery. The median sperm density was 17 (10-65) million/mL. Four men had normal sperm density and motility (>20 million/mL; >50% total motility). CONCLUSIONS: Men with idiopathic vaso-epididymal junction obstruction can have significant sperm positivity after vaso-epididymostomy. With a patency rate of nearly half within a year of surgery, vaso-epididymostomy should be the first line of therapy for these men.

Adult↗
PubMed2006

Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome.

AIM: To study the occurrence of Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome (KFS). METHODS: Blood and semen samples were collected from azoospermic patients with KFS (n = 14) and a control group of men of proven fertility (n = 13). Semen analysis was done according to World Health Organization (WHO) guidelines. Blood samples were processed for karyotyping, fluorescent in situ hybridization (FISH) and measurement of plasma follicle stimulating hormone (FSH) by radioimmunoassay. To determine Y chromosome microdeletions, polymerase chain reaction (PCR) of 16 sequence tagged sites (STS) and three genes (DFFRY, XKRY and RBM1Y) was performed on isolated genomic DNA. Testicular fine needle aspiration cytology (FNAC) was done in selected cases. RESULTS: Y chromosome microdeletions spanning the azoospermia factor (AZF)a and AZFb loci were found in four of the 14 azoospermic patients with KFS. Karyotype and FISH analysis revealed that, of the four cases showing Y chromosome microdeletion, three cases had a 47,XXY/46,XY chromosomal pattern and one case had a 46,XY/47,XXY/48,XXXY/48,XXYY chromosomal pattern. The testicular FNAC of one sample with Y chromosome microdeletion revealed Sertoli cell-only type of morphology. However, no Y chromosome microdeletions were observed in any of the 13 fertile men. All patients with KFS had elevated plasma FSH levels. CONCLUSION: Patients with KFS may harbor Y chromosome microdeletions and screening for these should be a part of their diagnostic work-up, particularly in those considering assisted reproductive techniques.

Adolescent↗
PubMed2005

Clinical and neuroimaging correlates of mild cognitive impairment in a middle-aged community sample: the personality and total health through life 60+ study.

This cross-sectional study aimed at determining the clinical and structural brain magnetic resonance imaging correlates of mild cognitive impairment (MCI). The data presented here are from the first wave of the longitudinal Personality and Total Health through Life 60+ project. 2,551 community-dwelling individuals in the age range of 60-64 years were recruited randomly through the electoral roll. They were screened using Mini-Mental State Examination and a short cognitive battery. Those who screened positive underwent detailed medical and neuropsychological assessments. Of the 224 subjects who screened positive, 117 underwent a detailed assessment. Twenty-nine subjects fulfilled the Mayo Clinic criteria for MCI. Magnetic resonance imaging scans were analyzed for 26 subjects with MCI as well as normal controls. Subjects were clinically evaluated for depressive symptoms and major and minor depression syndromes. Logistic regression analysis was performed predicting MCI from anterior and mid-ventricular brain ratios, cortical atrophy measures, hippocampal volumes, volumes of amygdala and white matter hyperintensities after adjusting for age, gender, years of education, depression and physical disability. None of the neuroanatomical substrates appeared as predictors of MCI. The only predictors were higher depression scores and fewer years of education. Structural neuroimaging may not have an added advantage in the detection of MCI in middle-aged community-dwelling subjects. It may be that this age group is too young for such brain changes to be identified.

Amygdala↗
PubMed2005

Modified expanded corrole-ferrocene conjugates: syntheses, structure and properties.

Syntheses, characterization and properties of expanded corrole-ferrocene conjugates are reported. Ferrocenyl group are covalently linked to the corrole macrocycle through three different spacers groups. The synthetic strategy involved prior insertion of ferrocene with spacers to the dipyrromethane unit followed by a "3+2" acid-catalyzed oxidative coupling methodology. The optical and emission data of the expanded corrole-ferrocene conjugates depend on the nature and length of the spacer groups and the maximum effects are seen where ferrocene is directly linked to the meso carbon of macrocycle. The single crystal X-ray structure of two expanded corrole-ferrocene conjugates; [22]pentaphyrin (1.1.0.1.0) with different meso substituents, clearly reveal shortening of the C-C bond length linking the meso carbon and the aryl substituent containing the ferrocene moiety relative to meso aryl substituents without ferrocene. The results suggest that an electronic interaction between the two pi systems. Electrochemical data reveal harder oxidation for the ferrocene unit in the conjugates relative to free ferrocene; this suggests the electron donating nature of the ferrocene. The first corrole ring oxidation shows easier oxidation relative to 1 and the magnitude of shifts in potential is inversely proportional to the length of spacer. The molecular first hyperpolarizabilities (beta) measured at 1064 nm by HRS method vary in the range 20-32x10(-30) esu and imply that the beta values can be increased by enhancing the number of mobile electrons in the conjugation. The conjugates form 1:1 metal complex with the Rh(I) where rhodium is coordinated to one amino and one imino nitrogen of the dipyrromethane unit.

Crystallography, X-Ray↗
PubMed2005

Characterisation of plant tocopherol cyclases and their overexpression in transgenic Brassica napus seeds.

Tocopherols, collectively known as vitamin E, are only synthesised in photosynthetic organisms. Tocopherol cyclase (TC) catalyses the formation of the chromanol headgroup of the various tocopherol isoforms. TCs from Arabidopsis and maize (Zea mays) were expressed in Escherichia coli and purified. Analysis of the enzymatic properties revealed similarities but also differences between the two enzymes. Overexpression of chimeric TC gene constructs in developing seeds of transgenic rapeseed plants enhanced and modified the relative abundance of individual tocochromanol species in the seed oil, indicating a regulatory function of the enzyme in prenyllipid metabolism.

Arabidopsis↗
PubMed2005

Long-term safety, efficacy, dosing, and development of resistance with botulinum toxin type B in cervical dystonia.

Short-term studies of cervical dystonia (CD) have demonstrated botulinum toxin type B (Bot B) to be safe and efficacious at doses of 5,000 to 10,000 units, but few long-term studies have been published and the safety and efficacy of higher doses has not been established. Additionally, there are few studies describing the development of resistance to Bot B in those with and without prior resistance to botulinum toxin type A (Bot A). We reviewed our experience with 24 patients treated with Bot B for up to 64 months. Patients were treated with Bot B for 26.2 +/- 20.4 months (range, 3-64 months) with a mean treatment dose of 14,828 +/- 6,824 units (range, 2,500-28,000 units). At last follow-up, 12 patients demonstrated ongoing benefit, 8 patients had become secondarily resistant, and 4 patients were primary nonresponders possibly due to the severity and nature of their CD. Nine of the 12 continued responders and 7 of the 8 secondary nonresponders to Bot B had prior probable or definite clinical resistance to Bot A. No severe adverse events related to Bot B were seen. Treatment of patients with severe CD who continue to show a beneficial response to Bot B injections commonly requires doses of 15,000 units and rarely greater than 20,000 units. Patients may continue to respond for up to 64 months. Prior Bot A resistance may be a risk factor for the development of resistance to Bot B; nevertheless, Bot B can be a useful long-term alternative in some Bot A-resistant CD patients.

Adult↗
PubMed2005

Separated quadrupolar field experiment.

We describe an NMR experiment that produces spectra correlating the first-order quadrupolar spectrum and the central transition spectrum of half-integer quadrupolar spins, allowing one to separate the quadrupolar parameters in overlapping spectra under both static and magic-angle-spinning conditions. Promising fields of applications include situations where the sample cannot easily be rotated, or where it cannot be rotated at the magic angle.

Magnetic Resonance Spectroscopy↗
PubMed2005

Retroperitoneoscopic decortication of symptomatic renal cysts.

PURPOSE: To determine the safety and efficacy of retroperitoneoscopic decortication of symptomatic renal cysts. PATIENTS AND METHODS: A total of 24 patients with symptomatic 6- to 14-cm (mean 10.9-cm) simple renal cysts, right sided in 13 and left sided in 11, underwent retroperitoneoscopic decortication for pain relief at our center between January 1997 and December 2002. The diagnosis was based on an ultrasonogram and contrast-enhanced CT. Symptom severity, assessed using a visual analog pain scale, averaged 7.2/10 (range 6.5-9). The mean duration of symptoms was 4 months. Operative and follow-up data were collected prospectively and analyzed for symptomatic and objective evidence of improvement. RESULTS: The mean operating time was 95 minutes, and no major complications were observed. The average hospital stay was 2.9 days (range 2-7 days). At a mean follow-up of 2.8 years (range 1.5-5 years), pain relief was reported by 22 patients (change of pain score from 7.2 to 1.4). One patient had worsening of pain at 6 weeks postoperatively. Asymptomatic recurrence of the cyst was seen in two patients on the follow-up ultrasound scans. CONCLUSIONS: Retroperitoneoscopic renal-cyst decortication is a safe, minimally invasive, and efficacious procedure for the treatment of painful renal cysts, with a durable response.

Adult↗
PubMed2005

Simultaneous laparoscopic adrenalectomy for pheochromocytoma and dismembered pyeloplasty for uretero-pelvic junction obstruction.

Laparoscopic adrenalectomy for pheochromocytoma and laparoscopic dismembered pyeloplasty are both technically difficult procedures. We describe the case of a 61-year-old female patient who presented with a right adrenal pheochromocytoma and bilateral pelvi-ureteric junction obstruction with renal failure who underwent a successful simultaneous transperitoneal laparoscopic adrenalectomy and pyeloplasty.

Acute Kidney Injury↗
PubMed2005

Contribution of investigations to the diagnosis of bilateral vas aplasia.

BACKGROUND: Bilaterally absent vas deferens is a surgically uncorrectable cause of male infertility. It is usually diagnosed clinically. We evaluate the role of semen analysis and radiological imaging in providing objective evidence of vas aplasia. METHODS: Twenty consecutive patients with clinically suspected bilateral vas aplasia were enrolled for this prospective study. They were investigated on the basis of an algorithm till corroborative evidence for vas aplasia was obtained. This successively included a semen analysis on at least two occasions, transrectal ultrasonogram (TRUS), pelvic magnetic resonance imaging (MRI) and scrotal exploration. The contribution of each investigation to confirming the diagnosis was evaluated. RESULTS: Seventeen patients (85%) had a low volume ejaculate while all 20 had azoospermia and semen fructose levels below normal. Semen pH was non-acidic in 75% of cases and thus was not contributory to the diagnosis. TRUS and MRI were non-contributory in 30% and 50% of evaluations, respectively. The clinical diagnosis was found to be correct in all patients. CONCLUSIONS: Vas aplasia is a clinical diagnosis. Low volume ejaculate with azoospermia and low or absent semen fructose is sufficient corroborative evidence and no further investigations are required for this diagnosis.

Adult↗
PubMed2005

MRI hyperintensities and depressive symptoms in a community sample of individuals 60-64 years old.

OBJECTIVE: Previous studies have found associations of magnetic resonance imaging (MRI) signal hyperintensities with depression in the elderly. The present study investigates the association in a younger community sample (age 60-64 years) of depressed subjects and comparison groups for potential mediating and confounding variables. METHOD: A subsample of 475 persons 60-64 years of age from a larger community survey underwent brain MRI scans. White matter hyperintensities were quantified by using an automated procedure, and basal ganglia hyperintensities were quantified by using semiquantitative visual ratings. The study also assessed depressive symptoms and use of antidepressant medication. Potential mediating or confounding variables assessed included physical disability, hypertension, stroke, diabetes, head injury, cortisol, thyroid-stimulating hormone, cognitive functioning, smoking, and alcohol use. RESULTS: Depressive symptoms were found to be related to total brain white matter hyperintensities but not to basal ganglia hyperintensities. However, associations disappeared when statistical adjustment was made for physical disability and smoking. CONCLUSIONS: Depressive symptoms are related to white matter hyperintensities in mid-adult life in a community sample. Physical disability appears to play an important role in this association.

Age Factors↗
PubMed2005

Social class and all-cause mortality in an urban population of North India.

BACKGROUND: There is a rapid emergence of cardiovascular disease in India with economic development, leading to an increase in mortality due to these diseases. The exact causes of death in India, however, are not known. SUBJECTS AND METHODS: We studied randomly selected death records from 2222 (1385 men and 837 women) victims, aged 25-64 years, out of 3034 death records during 1999-2001 at the Municipal Corporation, Moradabad. All the families of these victims could be contacted individually to find out the causes of death, by scientists/doctors-administered pre-tested verbal autopsy questionnaires, completed with the help of spouses and local treating doctors practising in the concerned lane. Social classes were assessed by a questionnaire based on attributes of per capita income, occupation, education, housing and ownership of consumer luxury items in the household. RESULTS: Causes of mortality included infectious diseases (41.1%, n = 915) such as tuberculosis, pneumonia, chronic obstructive pulmonary disease, diarrhea/dysentery, hepatitis B, and inflammatory brain infections as the commonest causes of death in the urban population of North India. The second most common causes of death were circulatory diseases (29.1%, n = 646), including heart attacks (10.0%), strokes (7.8%), valvular heart disease (7.2%, n = 160), sudden cardiac death, and inflammatory cardiac disease (each 2.0%, n = 44). Malignant neoplasm (5.8%, n = 131), injury (14.0%, n = 313), including accidents, fire and falls, and poisonings were also quite common causes of death. Miscellaneous causes of death were noted in 9.1% (n = 202) death records, including diabetes mellitus (2.2%, n = 49), suicides (1.8%, n = 41), congenital anomalies (1.0, n = 37), dental caries infections (1.9, n = 42), and burns (1.3%, n = 33). Pregnancy and perinatal causes (0.72%, n = 15) were not commonly recorded in our study. Circulatory diseases as the cause of mortality were statistically significantly more common among higher social classes (1-3) than in lower social classes (4 and 5) whose members died more often due to infections. Heart attacks, strokes, hypertension, diabetes and obesity were statistically significantly more common among higher social classes (1-3) as compared to classes 3 and 4, but tobacco intake showed only minor differences among various classes. CONCLUSIONS: This study indicates that circulatory diseases, injury and malignant diseases have become the major causes of death in India, after infections. Members of social classes 1-3 died more often due to circulatory diseases and members in lower social classes died more often due to infections. Urbanization with rapid changes in diet and lifestyle in various social classes, and possibly aging of the population seem to be responsible for the double burden of diseases, related to under- and over-nutrition, causing death in a developing economy. Monitoring of blood pressure and heart rate around the clock for 7 days, with data analysed chronobiologically can detect abnormal circadian patterns associated with a large increase in cardiovascular disease risk, greater than hypertension itself, allowing the institution of prophylactic treatment. Such prehabilitation may be particularly useful to curb the increasing burden of cardiovascular diseases in both developed and developing countries.

Adult↗
PubMed2004

Prevalence of mild cognitive impairment in 60- to 64-year-old community-dwelling individuals: The Personality and Total Health through Life 60+ Study.

This epidemiological study aimed at determining the prevalence of mild cognitive impairment (MCI) in 60- to 64-year-old individuals using different diagnostic criteria. Community dwelling individuals (n = 2,551) in the age range of 60-64 years were recruited randomly through the electoral roll. They were screened using the MMSE and a short cognitive battery, and those who screened positive underwent detailed medical and cognitive assessments. Extant MCI-related diagnoses were established by consensus. Predictive regression models on the sub-sample were used to determine population prevalence for the diagnoses. Of the 224 subjects who screened positive for MCI, 112 underwent a detailed assessment and 74% met the criteria for at least one recognised diagnosis of mild cognitive deficit (MCI and related diagnoses). By predictive regression modelling, the prevalence of any MCI diagnosis was 13.7% (95% CI 9.1-30.2) in the population of 60- to 64-year-olds. The estimated prevalence rates for specific diagnoses were: MCI 3.7%, ageing-associated cognitive decline 3.1%, Clinical Dementia Rating score (0.5) 2.8%, age-associated memory impairment 1%, other cognitive disorders 0.9%, and mild neurocognitive disorder 0.6%. Agreement on 'caseness' between various proposed diagnoses was at best fair and generally poor. Memory and other cognitive problems not meeting the threshold for dementia are relatively common in 60- to 64-year-old individuals living in the community. The prevalence rate varies up to six-fold according to the diagnostic criteria applied, with limited overlap between diagnoses. There is an urgent need for standardization of the criteria.

Activities of Daily Living↗
PubMed2004

Oxasmaragdyrin-ferrocene and oxacorrole-ferrocene conjugates: synthesis, structure, and nonlinear optical properties.

Ferrocenyl macrocyclic conjugates involving 22 pi oxasmaragdyrins and 18 pi oxacorroles have been synthesized and characterized. The direct covalent linkage of the ferrocenyl moiety to the meso position of the macrocycle is achieved by simple oxidative coupling of appropriate precursors with trifluoroacetic acid as catalyst. The electronic coupling between the ferrocenyl moiety and the macrocyclic pi system is apparent from: a) the red shifts (293-718 cm(-1)) of the Soret and Q-bands in the electronic absorption spectra of ferrocenyl conjugates; b) the shift of oxidation potentials (50-130 mV) of both the ferrocene and the corrole rings to the positive potentials; and c) considerable shortening of the C-C bond which connects the ferrocene and the meso-carbon atom of the macrocycle. The single-crystal X-ray structure of oxasmaragdyrin-ferrocene conjugate 9 reveals the planarity of the 22 pi skeleton with very small deviations of the meso-carbon atoms. The meso-ferrocenyl substituent has a small dihedral angle of 38 degrees, making way for mixing of the molecular orbitals of the ferrocene and the macrocycle. However, the other two meso substituents are almost perpendicular to the mean plane, defined by the three meso carbon atoms. Classical C-H...O and nonclassical C-H...pi interactions lead to a two-dimensional supramolecular network. Ferrocene-smaragdyrin conjugate 9 bonds to a chloride ion in the protonated form and a rhodium(i) ion in the free base form. Nonlinear optical measurements reveal a larger nonlinear refractive index (-5.83 x 10(-8)cm(2)W(-1)) and figure of merit (2.28 x 10(-8)cm(3)W(-1)) for the rhodium smaragdyrin-ferrocene conjugate 19 than for the others, suggesting its possible application in optical devices.

Journal Article↗
PubMed2004

Homocysteine and the brain in midadult life: evidence for an increased risk of leukoaraiosis in men.

BACKGROUND: High serum homocysteine (HCY) levels have been associated with thromboembolic cerebrovascular disease, but their relationship to microvascular disease is uncertain. Homocysteine also has a direct neurotoxic effect and has been linked to brain atrophy and an increased risk of Alzheimer disease. OBJECTIVE: To examine the relationship of HCY levels to brain and cognitive measures in a healthy community sample. DESIGN: Cross-sectional study. SETTING: Individuals residing in Canberra and Queanbeyan, Australia, who were participating in the longitudinal PATH Through Life Project. PARTICIPANTS: Individuals aged 60 to 64 years selected randomly from the community, 196 men and 189 women. MAIN OUTCOME MEASURES: Regression coefficients with HCY level as the putative determinant and various magnetic resonance imaging measures (brain atrophy index, ventricle-brain ratios, volume of periventricular and deep white matter hyperintensities) and cognitive measures (information processing speed, verbal memory, fine motor speed) as dependent measures. RESULTS: Homocysteine levels did not have a significant relationship with brain atrophy index or ventricle-brain ratios. High HCY levels were related to increased deep white matter hyperintensities but not periventricular white matter hyperintensities, after correcting for levels of folate, vitamin B(12), creatinine, and thyrotropin; hypertension; smoking; and diabetes, the relationship being significant only in men. Homocysteine levels were related to impairment in verbal memory and fine motor speed but not after the previously mentioned correction. CONCLUSIONS: Total HCY level is independently related to leukoaraiosis in middle-aged men, and this may be functionally relevant in the form of mild cognitive impairment. The remediation of hyperhomocysteinemia should begin early in life if its deleterious effects on the brain are to be prevented.

Brain↗
PubMed2004

Radical cystectomy in septuagenarian patients with bladder cancer.

INTRODUCTION: Clinical results of radical cystectomy performed on elderly bladder cancer patients over 70 years old were assessed to determine whether age is one of the critical points for the application of this type of surgery. MATERIALS: From January 1992 to December 2002, 41 radical cystectomy performed in septuagenarian population were compared with 197 performed in patients less than 70 years of age. RESULTS: The early and late complication rate for septuagenarians was 29.7% and 12%, compared with 26.9% and 9.6% for patients younger than 70 years respectively. The overall mortality rate for septuagenarians was 4.9%, compared with 8.6% for patients younger than 70 years. There was no significant difference between the two groups with regard to pathologic stage or length of hospital stay. The 5-year overall survival rate for septuagenarians was 53% compared with 59% for patients younger than 70 years. CONCLUSIONS: When indicated after adequate preoperative assessment and optimization of the patient, radical cystectomy is a safe procedure in the septuagenarians and patient should not be denied surgery dependent on chronologic age.

Aged↗
PubMed2004

Renal cell cancer in solitary kidney after donor nephrectomy.

The occurrence of renal cell carcinoma in the solitary remnant kidney after donor nephrectomy is rare and, to our knowledge, has not been previously reported. We encountered 2 such patients in whom cancer occurred 19 and 40 years after the donation. Both patients underwent successful partial nephrectomy for the tumor using two different techniques.

Carcinoma, Renal Cell↗