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Biomedical subjects

K R Krishnan

Publications and source records attributed to K R Krishnan.

At least 73 records · Page 4Linked to original sources
PubMed1998

Familial leukoencephalopathy in bipolar disorder.

OBJECTIVE: Imaging studies of patients with bipolar disorder demonstrate changes in deep white matter and subcortical gray nuclei that are seen as focal hyperintensities on T2-weighted magnetic resonance imaging (MRI). The objective of this study was to examine MRIs in a family with a strong history of bipolar disorder to look for possible MRI abnormalities in members with and without affective illness. METHOD: The authors obtained MRIs of 21 members of a family with a strong history of bipolar disorder. Eight of the family members studied had bipolar illness, one had symptoms of bipolar disorder but did not meet full DSM-III-R criteria, two had unipolar disorder, and 10 did not have bipolar disorder. RESULTS: Fifteen of the 21 family members had MRI findings, including six of 10 family members who had no affective disorder and all of those with bipolar disorder. Lesions of both white matter and subcortical gray nuclei were found. CONCLUSIONS: Although the clinical significance of these MRI findings is unknown, the high prevalence of MRI findings in both affected and unaffected family members suggests that MRI findings may potentially serve as a biological marker for bipolar disorder. Recent genetic studies have established a link between familial leukoencephalopathy and chromosome 19. If leukoencephalopathy appears to be related to bipolar disorder, it may allow clearer characterization of the genetics of the disorder.

Adolescent↗
PubMed1998

Age of first onset of bipolar disorder: demographic, family history, and psychosocial correlates.

The literature suggests that bipolar elders with early and late onset of the disorder present with different demographic, family history, and psychosocial profiles, which are less well characterized than those for elderly unipolar patients. In this cross-sectional clinical survey, we assessed subjects (n = 74) from the NIMH Clinical Research Center for the Study of Depression in Later Life at Duke University who had a consensus diagnosis of bipolar depression; the primary assessment instrument was the Duke Depression Evaluation Schedule. We found that bipolar subjects with later age of onset reported less family history of psychiatric problems, more comorbid vascular disease, and more instrumental and subjective social support. Stressful life events were more frequent among bipolar subjects with earlier age of depressive symptom onset. This study suggests that early-onset disorder may be characterized by a psychosocial component, whereas organic factors may be particularly important to late-onset bipolar disorder.

Adult↗
PubMed1997

Psychosocial and physical correlates of chronic depression.

This study used a case-control design to address differences in psychosocial, physical and clinical profiles between subjects who presented with a chronic index episode of major depression and those who presented with a non-chronic index episode. Subjects were adult patients participating in the Duke University Mental Health Clinical Research Center (MHCRC) for the Study of Depression in Later Life. Cases (N = 88) who reported duration of depressive symptoms lasting > or = 24 months at enrollment were compared to controls (N = 354) who reported symptoms lasting 1-12 months. The groups were compared with respect to selected demographic and clinical variables, physical function deficits, medical comorbidity, social support constructs and number of recent stressful life events. Social support and physical health were more relevant to chronicity of major depressive illness than were severity of illness or family history. Older age (> 60 years) intensified the deleterious effect of recent negative life events and reduced the deleterious effect of functional impairment on chronic major depression. These findings require special emphasis where treatment for chronic major depression is divorced from considerations of the social environment and functional capacity.

Activities of Daily Living↗
PubMed1997

A repeat proton magnetic resonance spectroscopy study in social phobia.

Peak spectral amplitudes for choline moieties (Cho), creatine (Cr), N-acetylaspartate (NAA), and myo-inositol (mI) were examined using proton magnetic resonance spectroscopy in 19 social-phobia patients and 10 controls. Compared with controls, social phobics demonstrated significantly lower NAA/Cho and higher Cho/Cr, mI/Cr, and mI/NAA amplitudes in cortical gray matter. Higher mI/Cr and mI/NAA amplitudes for social phobics were also observed in subcortical gray matter. Minimal between-group differences were noted for white matter. Symptom severity correlated inversely with amplitudes primarily in subcortical gray matter, and to a lesser extent in cortical gray matter. Inclusion of age and sex in statistical modeling strengthened comparisons with controls but eliminated those for symptom severity. No changes were observed in any amplitude measure following at least 8 weeks of clonazepam treatment, nor was a relationship observed between amplitudes and cumulative clonazepam dose. The possible psychobiological implications of our findings in social phobia are discussed.

Adult↗
PubMed1997

Are SSRIs better than TCAs? Comparison of SSRIs and TCAs: a meta-analysis.

In this analysis we examined studies of tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) to compare efficacy and drop-out rates. Frequency of reported side effects was also studied. Using Medline, we located 36 clinical trials of TCAs and SSRIs in a double-blind comparison. We performed a meta-analysis on these studies and on a subgroup of 21 studies that had more uniformly defined outcome criteria. The main outcome measures were efficacy for treatment completers and for the intention-to-treat group; drop-out rates due to adverse reactions and lack of efficacy; and reported side effects. Overall, the response rate to treatment for patients who completed a trial was 63.2% for SSRIs and 68.2% for TCAs (P = 0.038). For the intention-to-treat groups, these rates dropped to 48.0 and 48.6% (P, NS), respectively. Significantly more TCA-treated than SSRI-treated subjects dropped out due to either lack of efficacy or adverse reactions (30.0 vs. 24.7%, P = 0.01). Patients taking SSRIs experienced significantly more gastrointestinal problems and sexual dysfunction, whereas treatment with TCAs produced significantly more complaints of sedation, dizziness, and anticholinergic symptoms.

Antidepressive Agents, Tricyclic↗
PubMed1997

Urine leakage from the umbilicus in a child with achondroplasia and tetraplegia (due to cervical stenosis): a safety vent for the obstructed neuropathic bladder.

Urine leakage from the umbilicus was observed while expressing urine by the Crede manoeuvre in a three-year-old tetraplegic girl with a chronically distended urinary bladder. Intravenous urography (IVU) revealed bilateral hydroureteronephrosis with markedly distended urinary bladder. Regular three hourly intermittent catheterization was advised, and the parents and carers of this child agreed to perform catheterization. There was cessation of urine leak within 48 hours of urethral drainage. Cystography performed two weeks later showed no vesicoureteric reflux; vesicoumbilical fistula was no longer demonstrable. Follow-up IVU, performed after eight and half months of regular intermittent catheterization, showed regression of hydroureteronephrosis. We believe that urine leakage from the umbilicus served two important protective functions in this child, viz. (1) it prevented possible vesical or renal rupture; (2) the striking clinical symptom of urine leak from the umbilicus focussed the attention of the carers to the underlying serious condition of the urinary tract. Further, this case demonstrates that regression of marked hydroureteronephrosis can be achieved by intermittent catheterization performed at regular intervals by devoted parents/carers, in selected cases of spinal cord injury with neuropathic bladder, and vesical outlet obstruction, thus obviating the need for any form of temporary or permanent urinary diversion.

Achondroplasia↗
PubMed1997

Age and sex effects on brain morphology.

1. Brain morphology can be assessed readily in vivo using magnetic resonance imaging (MRI). 2. In this study, the effects of age and sex on whole-brain morphology were examined using an operator-controlled computer-segmentation protocol. 3. Results indicated that age was associated with gray-matter volume reduction. 4. Brain-size differences between males and females were primarily attributable to white-matter volume. 5. This study confirms the importance of controlling for age and sex in brain-morphology studies.

Adult↗
PubMed1997

A new MRI ratio method for in-vivo estimation of signal hypointensity in aging and Alzheimer's disease.

1. Alzheimer's Disease (AD) is accompanied by a disruption in iron metabolism. There is no universally accepted method for detecting brain iron. 2. The authors have developed a novel "ratio" method which uses the red nucleus as an internal reference. We postulated that this method would improve our sensitivity in detecting differences in MRI signal intensities and that it would allow us to measure brain iron deposition. 3. The ratio method reasonably reproduced previous reports of the normal deposition of iron in brain that occurs with aging. It failed to distinguish any differences in three brain areas: putamen, left frontal lobe and whole slice in AD patients versus age and sex matched controls. 4. It also failed to detect differences with AD progression or severity. 5. The ratio method itself warrants further investigation.

Aged↗
PubMed1997

Structural changes in the brain of patients with bipolar affective disorder by MRI: a review of the literature.

1. Current literature was searched to evaluate the use of magnetic resonance imaging in patients with bipolar disorder. 2. The presence of white matter hyperintensities, differences in temporal lobe and hippocampal structures, and ventricular enlargement in patients with bipolar disorder was assessed. 3. Further use of MRI in patients with bipolar disorder is reviewed.

Bipolar Disorder↗
PubMed1997

Screening for trauma history on an inpatient affective-disorders unit: a pilot study.

Psychiatric inpatients (N = 343) admitted to an affective-disorders unit were administered a self-rating Trauma Questionnaire (TQ) to evaluate life history of traumatic experiences. Eighty four percent of the sample identified at least one traumatic-event category (M = 2.27 categories/patient). Symptoms consistent with posttraumatic stress disorder (PTSD), were highly prevalent. However, only six patients received a chart diagnosis of posttraumatic stress disorder. Female patients evidenced more PTSD symptoms than males, in contrast to an equal number of event categories identified by the two sexes. Age correlated negatively with number of symptoms endorsed. Implications for trauma screening in affective-disorder patients are discussed.

Adolescent↗
PubMed1997

MRI-defined vascular depression.

OBJECTIVE: The authors' goal was to characterize the clinical and demographic features of vascular depression. METHOD: They classified 89 depressed patients into two groups-those with vascular (N = 32) and nonvascular (N = 57) depression-on the basis of examination of brain magnetic resonance images. All of the patients were enrolled in the National Institute of Mental Health Clinical Research Center for the Study of Depression in Later Life, located at Duke University. The patients with vascular and nonvascular depression were compared on several clinical and demographic risk factors. RESULTS: Bivariate analyses and a fully adjusted logistic regression model revealed that older age, late age at onset, and nonpsychotic subtype occurred more often in patients with vascular depression than in those with nonvascular depression. A family history of mental illness was found somewhat less often, and anhedonia and functional disability were seen somewhat more often in patients with vascular depression. CONCLUSIONS: The profile of patients with vascular depression needs to be developed further. This is likely to have important therapeutic and theoretical implications for the management of these patients.

Adult↗
PubMed1997

The Alzheimer's Disease Assessment Scale: patterns and predictors of baseline cognitive performance in multicenter Alzheimer's disease trials.

The cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog) is used as an efficacy measure in clinical drug trials of Alzheimer's disease (AD). We used data from 1,648 AD participants in two identical 26-week multicenter drug trials to examine the distribution of baseline ADAS-Cog scores in relation to selected demographic and clinical variables, Mini-Mental State Exam (MMSE), Global Deterioration Scale (GDS), and Geriatric Evaluation by Relative's Rating Instrument (GERRI) scores. At baseline, the mean (+/-SD) MMSE score was 18 +/- 4, the ADAS-Cog score was 28 +/- 11, and most subjects were in GDS stage 4 or 5. The ADAS-Cog score was statistically significantly correlated with MMSE (R = -0.76, p < 0.0001) and GERRI (R = 0.40, p < 0.0001) total scores. Correlations among the ADAS-Cog items ranged from 0.19 to 0.59 and all were statistically significant (p < 0.0001). In a multiple regression model, younger age, male gender, older age at onset of dementia, use of concurrent estrogen, and use of concurrent anti-inflammatory agents were statistically significantly associated with superior cognitive performance. We also present data on the distribution of ADAS-Cog scores in relation to subjects' age, level of education, MMSE score, and GDS stage. Because age, MMSE score, and GDS stage (and not the ADAS-Cog) are commonly used to select subjects for AD clinical trials, our data should improve the ability of sponsors to predict ADAS-Cog scores of the subjects in their trials on the basis of the inclusion criteria used. Our data also suggest that age, gender, age at onset of dementia, level of education, and use of estrogen (in women) or anti-inflammatory drugs are related to cognitive abilities in AD. Further studies are needed to assess how and when cognitive differences related to these variables arise.

Aged↗