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Biomedical subjects

R Raman

Publications and source records attributed to R Raman.

At least 37 records · Page 2Linked to original sources
PubMed2003

Isomerism of the right atrial appendages: clinical, anatomical, and microscopic study of a long-surviving case with asplenia and ciliary abnormalities.

This study describes a case of isomerism of the right atrial appendages (bilateral morphologically right atrial appendages associated with complex congenital cardiac lesions) with ciliary abnormalities. Detailed investigation included gross anatomic dissection, review of the clinical history, and light, confocal, and electron microscopy. Clinically, this 40-year-old, long-surviving male patient had relatively good health until 4 years before death, which was due to cardiac failure. Surgical intervention consisted only of a Blalock-Taussig shunt (anastomosis of the right subclavian artery to the right pulmonary artery) at 6 years of age. Despite the presence of complex cardiac malformations and asplenia, his longevity may be attributed to the connection of the pulmonary veins to the atrium without pulmonary venous obstruction, pulmonary valvar stenosis rather than atresia, no significant atrioventricular valve regurgitation, and no serious infections during his life. Microscopic examination of bronchial epithelium revealed a narrow, disorganized epithelium with abundant goblet cells and short, angulated cilia with a random orientation and possibly an abnormal central microtubule doublet. These abnormalities were not present in controls, and have been noted in primary ciliary dyskinesia (PCD) or Kartagener's syndrome. Because this syndrome has classically been thought to cause random lateralization resulting in a mirror-imaged arrangement of the organs, the occurrence of truly isomeric patterns is not widely recognized. Whereas polysplenia and left bronchial isomerism have been reported to occur in immotile cilia syndrome, this is the first report to present detailed postmortem anatomic evidence of isomerism of the right atrial appendages, right bronchial isomerism, and asplenia in association with microscopy suggesting ciliary abnormalities.

Adult↗
PubMed2003

Idiopathic cases of male infertility from a region in India show low incidence of Y-chromosome microdeletion.

Chromosomal and Y-chromosomal microdeletion analysis has been done in cases of idiopathic infertility with the objective of evaluating the frequency of chromosomal and molecular anomaly as the causal factor of infertility. Barring a few cases of Klinefelter syndrome (XXY or XY/XXY mosaics), no chromosomal anomaly was encountered. Y-microdeletion was analysed by PCR-screening of STSs from different regions of the AZF (AZFa, AZFb, AZFc) on the long arm of the Y, as well as by using DNA probes of the genes RBM, DAZ (Yq), DAZLA (an autosomal homologue of DAZ) and SRY (Yp; sex determining gene). Out of 177 cases examined, 9 (azoospermia - 8 and oligoasthenospermia - 1) showed partial deletion of AZF. The size of deletion varied among patients but AZFc was either totally or partially removed in all of them. In contrast, no deletion was detected in AZFa. Testis biopsy done on a limited number of cases (50) showed diverse stages of spermatogenic arrest with no specific correlation with the genotype. The frequency of Y-chromosome microdeletion in our samples (approximately 5%) is much lower than the frequency (approximately 10%) reported globally and the two previous reports from India. We contend that the frequency may be affected by population structures in different geographical regions.

Biopsy↗
PubMed2002

Gender and pramipexole effects on levodopa pharmacokinetics and pharmacodynamics.

The authors studied the pharmacokinetics of levodopa (LD) with and without pramipexole (PPX) in men and postmenopausal women with PD. Patients on stable dose of carbidopa/LD were randomized to receive escalating doses of placebo or PPX over 7 weeks. LD and PPX pharmacokinetics were performed after a single test dose 25/100 of carbidopa/LD, before initiation of PPX or placebo, at 1.5 mg/d and 4.5 mg/d of PPX or placebo. Compared to men, women had greater LD bioavailability. PPX did not alter LD bioavailability, and PPX pharmacokinetics were equivalent in men and women.

Aged↗
PubMed2002

Otological disorders in Down's Syndrome.

OBJECTIVE: To assess if children with Down's Syndrome have a higher prevalence of otological abnormality compared to their normal counterparts in Malaysia. METHODOLOGY: Thirty children with Down's Syndrome and normal children underwent otoscopic ear examination and Impedance test in the ENT outpatients clinic in University Hospital, Kuala Lumpur, Malaysia. RESULTS: The study showed that children with Down's Syndrome had higher otological disorders. Forty four percent had impacted wax compared to 14.4% in normal children. Twenty one percent of ears in the study group had retracted drums compared to 6.6% of control. Fifteen percent of ears in the study group had middle ear effusion compared to 3.4% in controls, 55% had a type B tympanogram compared to 8.3% in controls and 73.4% had auditory canal stenosis compared to 14.4% in controls. CONCLUSION: Children with Down's Syndrome, thus have a higher incidence of otological disorders.

Child↗
PubMed2001

Prospective longitudinal assessment of hallucinations in Parkinson's disease.

OBJECTIVE: To monitor the evolution of hallucinations over 4 years in a stratified sample of patients with PD. METHODS: Using a modified version of the Unified PD Rating Scale (UPDRS) Thought Disorder question, the authors stratified patients into five baseline behavioral groups. They recruited up to 20 patients for each group to participate in sequential interviews (Rush Hallucination Inventory) at baseline and 6, 18, and 48 months. UPDRS motor examinations and Mini Mental State Examinations (MMSE) were obtained at baseline and 48 months. Data were analyzed with Wilcoxon rank sum tests, Mantel-Haenszel tests, and Spearman correlations. To determine features that influenced the new development of hallucinations, a cumulative logit regression model of hallucination severity over time was fit using generalized estimating equations. RESULTS: Based on the design stratification, 60 patients had no hallucinations at baseline (20 with no behavioral problems, 20 with sleep fragmentation, 20 with altered dream phenomena). Twenty-nine patients had hallucinations (20 with retained insight and 9 with loss of insight). At 48 months, the authors could account for all but two subjects (98% retrieval). In 4 years, the presence of hallucinations increased (33% at baseline, 44% at 18 months, and 63% at 48 months, p < 0.0001). The presence of frequent hallucinations (at least three times weekly) also increased (p = 0.0002). Having hallucinations at baseline or at any given assessment was a strong predictor at all follow-up evaluations of continued hallucinations (p < 0.0001). Hallucinations were not associated with increased mortality (chi(2) = 0.59, df (1), p = 0.47). Among the 60 subjects without hallucinations at baseline, time was the only significant factor influencing the development of hallucination over 48 months. Baseline age, PD duration, sex, medications, and UPDRS or MMSE scores did not influence the incidence of hallucinations. CONCLUSIONS: This prospective, longitudinal study documents the persistent and progressive nature of hallucinations in PD patients on chronic dopaminergic therapy. The consistent association of hallucinations with combined levodopa/agonist therapy suggests that these drugs may play a role in the pathophysiology of hallucinations.

Aged↗
PubMed2001

Tonsillar actinomycosis: a clinicopathological study.

Actinomycosis has been known to involve virtually every anatomic site in the body. Although actinomycosis has been identified in resected tonsils, its possible role in adeno-tonsillar disease has received little attention. A clinicopathological study of 302 patients who had adeno-tonsillar surgery is presented. Tonsillar actinomycosis was present in 86 (28.5%) patients. The statistical analysis revealed a significant association (P<0.0001) of actinomycosis and tonsillar hypertrophy (56.8%) compared to only 10.3% in the recurrent tonsillitis group. A statistically significant association (P<0.0001) of tonsillar actinomycosis and sickle cell anaemia, beta thalassaemia, bronchial asthma and beta haemolytic streptococcal infections was also seen. This data supports a predisposition of the above conditions to tonsillar actinomycosis and adeno-tonsillar hypertrophy and a possible etiopathologic role of this organism in adeno-tonsillar hypertrophy and disease. Although the clinical association of actinomycosis and tonsillar hypertrophy and beta haemolytic streptococcal infection has been described before the association of actinomycosis with sickle cell anaemia, beta thalassaemia and bronchial asthma is being observed for the first time in literature.

Actinomyces↗
PubMed2001

Probing fibroblast growth factor dimerization and role of heparin-like glycosaminoglycans in modulating dimerization and signaling.

For a number of growth factors and cytokines, ligand dimerization is believed to be central to the formation of an active signaling complex. In the case of fibroblast growth factor-2 (FGF2) signaling, heparin/heparan sulfate-like glycosaminoglycans (HLGAGs) are involved through interaction with both FGF2 and its receptors (FGFRs) in assembling a tertiary complex and modulating FGF2 activity. Biochemical data have suggested different modes of HLGAG-induced FGF2 dimerization involving specific protein-protein contacts. In addition, several recent x-ray crystallography studies of FGF.FGFR and FGF.FGFR.HLGAG complexes have revealed other modes of molecular assemblage, with no FGF-FGF contacts. All these different biochemical and structural findings have clarified less and in fact raised more questions as to which mode of FGF2 dimerization, if any, is essential for signaling. In this study, we address the issue of FGF2 dimerization in signaling using a combination of biochemical, biophysical, and site-directed mutagenesis approaches. Our findings presented here provide direct evidence of FGF2 dimerization in mediating FGF2 signaling.

Animals↗
PubMed2001

Genetic variation analysis in parkinson disease patients with and without hallucinations: case-control study.

BACKGROUND: Visual hallucinations in Parkinson disease (PD) occur in approximately one third of patients treated long-term with dopaminergic medications. In Alzheimer disease, hallucinations and psychosis have been linked to increased representations of B2/B2 homozyogotes for the dopamine receptor gene DRD1 and 1/1 or 2/2 homozygotes for DRD3. In addition, a previous study of PD patients with and without hallucinations did not show differences in D2 and D3 polymorphisms, although careful case-control matching was not performed. Another study linked the apolipoprotein E4 (APOE4) allele to hallucinations in PD. OBJECTIVE: To determine whether the frequency of dopamine receptor genetic variants and APOE alleles in patients with PD with and without chronic visual hallucinations resembles the pattern previously documented in patients with Alzheimer disease. METHODS: We conducted a case-control study of 44 patients with PD and chronic hallucinations and 44 patients with PD who had never hallucinated. Cases and controls were matched for current age and medications. DNA was isolated from blood samples and assayed for DRD1, DRD2, DRD3, DRD4, and APOE polymorphisms. Receptor polymorphisms were genotyped by polymerase chain reaction. Genotypes in hallucinators and nonhallucinators were compared using Mantel-Haenszel tests stratified by pair, and allele frequencies were compared using Wilcoxon signed rank tests within pairs. RESULTS: Neither D1 receptor genotypes (P =.37) nor allele frequencies (P =.38) differed, and there was no predominance of B2/B2 homozygotes in the hallucinators. For D3, there was a higher frequency of allele 2 (P =.047), but there was no significant difference between frequencies of homozygotes vs heterozygotes (P =.39) as reported in Alzheimer disease. D4 receptor distribution of long and short alleles did not differ between the 2 patient groups, and there were too few C alleles (3 of 86) to compare D2 allele genotypes or frequencies. For APOE, 12 cases and 12 controls carried E4 alleles (P>.99). CONCLUSIONS: With careful case-control matching, visual hallucinations in PD are not associated with the pattern seen for patients with Alzheimer disease and visual hallucinations. Furthermore, there was no association between hallucinations and APOE. Similar methods using larger sample sizes might be adapted to test whether specific dopaminergic receptor genetic variants are associated with visual hallucinations in PD. Based on our data, the DRD3 allele 2 may merit further study.

Aged↗
PubMed2001

Early morning off-medication dyskinesias, dystonia, and choreic subtypes.

BACKGROUND: Abnormal involuntary movements (dyskinesias) are common in patients with Parkinson disease (PD) as a consequence of the disease and dopaminergic replacement therapy. Early morning off-medication choreic dyskinesias have been recently reported after fetal dopaminergic cell transplantations in patients with advanced PD. OBJECTIVE: To determine the frequency and severity of the early morning off-medication dyskinesias in consecutive patients with advanced PD and an insufficient response to medical management before they undergo neurosurgery. METHODS: Consecutive patients with advanced idiopathic PD were examined and videotaped before undergoing neurosurgery that included pallidotomy, fetal transplantation, or deep brain stimulation. The examination took place in the morning in the practically defined off state, at least 12 hours after the last dose of dopaminergic drugs. Parkinson disease was characterized using the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr stage. Dyskinesias were rated with the Abnormal Involuntary Movements Scale and the Rush Dyskinesia Rating Scale. Patients' characteristics and medications were compared using the Wilcoxon rank sum and the Fisher exact tests. RESULTS: Of 68 consecutive patients (44 [65%] men and 24 [35%] women), 11 (16%) had early morning off-medication dyskinesia, with a 95% upper confidence limit of 24%. Focal dystonia was the most common off-medication dyskinesia, and occurred in 10 patients (15%), with a 95% upper confidence limit of 22%; and off-choreic dyskinesia occurred in 1 patient (1.5%), with a 95% upper confidence limit of 4%. There was no difference in PD medications between the patients with and those without dyskinesias. CONCLUSIONS: The most common form of off-medication dyskinesia seen in patients with advanced PD is dystonia. Early morning off-medication choreic dyskinesias are rare but do occur in patients with advanced PD before surgical intervention. The presence and type of off-medication dyskinesias should be monitored in clinical and surgical studies in patients with PD as part of the safety and evaluation of clinical benefits.

Adult↗
PubMed2001

A pilot survey of African-American physician perceptions about clinical trials.

African Americans have been underrepresented in clinical trials. However, African-American physician attitudes about clinical trials may influence patient recruitment. We identified the perceptions of African-American physician members of the Cook County Physicians Association (CCPA) about clinical trials in the Chicago Metropolitan area using a self-administered questionnaire. An 18-item, 2-page survey that included information about physician demographics, practice type, and specialty, and perceptions regarding clinical research was sent to each of the 609 active or inactive members of the CCPA, a predominantly African-American physician organization. Each survey was accompanied by a letter of explanation and a self-addressed, return envelope. Data from the surveys were stored and analyzed in a database. A total of 166 members (27%) completed the survey. Fifty percent of the respondents were men and 50% were women. The mean age of the group was 45 years, and almost half had participated previously as a local investigator, or assisted on a clinical or laboratory study. Factors identified by the members as possibly being disadvantages to participation in a clinical trial, or factors influencing African-American recruitment included: (a) lack of patient awareness of clinical trials (93%); (b) patient mistrust of the medical community (92%); (c) additional administrative tasks in conjunction with a patient enrolled in a study (56%); (d) blind drug assignment (41.6%). African-American physicians perceive inherent disadvantages from participation in clinical trials and have pinpointed factors that may influence patient recruitment. These factors may be addressed by focused physician and community education.

Black or African American↗
PubMed2001

A comparison of stroke risk factors in patients enrolled in stroke prevention trials.

The high prevalence of stroke risk factors may explain, in part, the high incidence of stroke in African Americans. To further investigate the role of stroke risk factors, we compared stroke risk factor profiles of patients in the African-American Antiplatelet Stroke Prevention Study (AAASPS) with those in other stroke prevention studies in which the enrollees were predominately white. The baseline characteristics of the AAASPS enrollees obtained from an interim AAASPS database of 1,087 patients from 65 centers in the U.S. between December 1995 and June 1999 was compared to the baseline characteristics of 53,293 predominantly non-African American patients enrolled in 23 other stroke prevention studies (pNAA). Percentages were reported for qualitative characteristics, and means and standard deviations (SDs) for quantitative characteristics. For selected qualitative characteristics, 95% confidence intervals were given for population percentages in each study. The comparison of baseline characteristics showed that hypertension was more prevalent in AAASPS (84% [95% CI 82.2, 86.61) compared to pNAA trial patients (range of 27% to 67%). Diabetes mellitus was more common in AAASPS (39.1%) compared to pNAA trial patients (17.1%). Cardiac disease, however, was less common in AAASPS than in pNAA trials. The frequency of baseline characteristics of AAASPS patients is different from those of pNAA studies. Risk factor profiles are important as they may help to predict stroke subtype and outcome. Furthermore, the differences in baseline characteristics may portend differences in response to treatment and incidence of adverse events.

Black or African American↗
PubMed2000

Menstrual-related changes in motoric function in women with Parkinson's disease.

Questionnaire studies have found that parkinsonism worsens in women during the premenstrual period, when estrogen and progesterone levels are presumably at their nadir. To assess this patient-based observation and correlate motor signs with hormonal levels, the authors prospectively studied 10 menstruating women with PD in their "off" state, on 5 successive weeks. Although PD severity fluctuated during the study period, there was no significant correlation between the objective or subjective measures of parkinsonism and estrogen and progesterone levels.

Adult↗