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Biomedical subjects

K R Krishnan

Publications and source records attributed to K R Krishnan.

At least 127 records · Page 7Linked to original sources
PubMed1994

Use of Memokath, a second generation urethral stent for relief of urinary retention in male spinal cord injured patients.

Memokath (Engineers & Doctors A/S, Hornbaek, Denmark) a second generation urethral stent composed of titanium nickel alloy with shape memory effect was deployed in 10 male spinal cord injured patients with urinary retention. The stent was inserted under sterile conditions via a delivery catheter under fluoroscopic control in seven and with the aid of a flexible cytoscope in three. The proximal end of the stent was positioned at the bladder neck and 50 ml of normal saline at 45 degrees C was flushed through the stent which resulted in expansion of the distal most four coils of the stent in the proximal bulbar urethra; thus the internal sphincter (bladder neck) and external sphincter zone were kept open by the stent. Urethral stenting helped to achieve complete vesical emptying in all 10 patients. The complications included transient autonomic dysreflexia in two, transient urinary retention due to blood clot in one, and acute urinary tract infection in one patient. With a follow up of 3-7 months, all 10 patients have been asymptomatic, with residual urine of less than 50 ml. There has been no migration or blocking of the stent. However, these stents require replacement at 12-18 months, but it is a short procedure as the Memokath, when cooled with saline at 4 degrees C, becomes supersoft, enabling its easy and nontraumatic removal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Urethral cytology in spinal cord injury patients performing intermittent catheterisation.

Local reactions of the urethral wall are known to occur by repeated introduction of a catheter in the urethra. Urethritis was found in 2-19% of patients practising intermittent catheterisation. Although the use of catheters of smaller size and the liberal use of lubricants may prevent urethral irritation and trauma, it was postulated that hydrophilic catheters (LoFric, Astra Tech Ltd, Stroud, England) induce significantly less trauma than PVC catheters because of the binding of the water molecules to the catheter surface which consists of polyvinylpyrrolidone and sodium chloride. Although urethritis and urethral stricture may represent one end of the spectrum of repeated urethral trauma, minor degrees of inflammation need to be quantitatively determined while assessing two different catheters for intermittent catheterisation. The degree of urethral inflammation in patients practising intermittent catheterisation was studied by urethral cytology and staining the smear by Papanicolaou's method. The number of neutrophil polymorphs and epithelial cells in three random high power fields in the urethral smear was counted and the percentage ratio of polymorphs to epithelial cells was calculated. Group 1 comprised 14 patients practising intermittent catheterisation with a PVC catheter and group 2 comprised 17 patients performing intermittent catheterisation with a LoFric catheter. There was no significant difference between the two groups as regards the age, diagnosis, size of the catheter used for intermittent catheterisation and the number of times that they performed catheterisation during a 24 hour period. Urethral cytology revealed a percentage (mean ratio) ratio of polymorphs to epithelial cells of 66 in group 1 and 0.04 in group 2. (< 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

A retrospective study of hyponatremia in tetraplegic/paraplegic patients with a review of the literature.

The aetiology of hyponatremia in tetraplegic patients is multifactorial and includes not only general factors such as the use of diuretics and the intravenous infusion of hypotonic fluids, but also certain mechanisms which operate in the spinal cord injured: decreased renal water excretion due to both intrarenal and arginine vasopressin dependent mechanisms (resetting of the osmostat), coupled with habitually increased fluid intake, and the ingestion of a low salt diet. Between 1984 and 1993 we treated 28 episodes of hyponatremia in 19 patients (males: 10; females: 9). Fourteen were tetraplegic and five paraplegic (thoracic lesion in four and lumbar lesion in one). Six patients were asymptomatic during seven episodes of hyponatremia which were detected during routine blood tests. Seven patients were suffering from an acute chest infection, three had an acute urinary tract infection, one had an infected ischial pressure sore and a 69 year old paraplegic patient had bronchopneumonia as well as sepsis from a gangrenous pressure sore in the supraanal region. The time interval between the onset of paralysis and occurrence of the first episode of hypnoatremia was less than a month in only four of the patients. The lowest plasma sodium level observed was less than 100 mmol/l in two, between 100 and 110 mmol/l in four, between 111 and 120 mmol/l in eight patients, and between 121 and 128 mmol/l in 14 cases. Six patients also had hypokalemia (K+ < 3 mmol/l). Only one patient had and elevated plasma creatinine (201 umol/l). Treatment of sepsis and fluid restriction were the mainstay of treatment with only two patients receiving hypertonic saline. All patients with underlying sepsis were treated with antibiotics, usually administered intravenously. The outcome was good in 26 of the 28 episodes. Two patients died: a 68 year old tetraplegic patient with consolidation of the left lung, cystadenocarcinoma of both ovaries and squamous cell carcinoma of the forehead who presented with generalised oedema, with a plasma sodium level of 118 mmol/l, and potassium of 2.4 mmol/l and who was treated with 2 N saline + potassium + frusemide; she died 1 day later. The only other death was that of a 78 year old female tetraplegic patient who 2 days after sustaining cervical trauma developed hyponatremia because of intravenous infusion of hypotonic fluids given at another hospital, presumably to correct hypotension. She recovered from hyponatremia with fluid restriction, but 3 days later she succumbed to bronchopneumonia and respiratory insufficiency. No patient developed central pontine myelinolysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1994

Further studies on platelet serotonin transporter binding in depression.

OBJECTIVE: There is an impressive literature implicating abnormalities in serotonergic neural systems in depression. Many investigators, but not all, have reported low numbers of platelet and brain serotonin (5-HT) transporter sites in drug-free depressed patients. In the present study the authors sought to determine whether the low platelet 5-HT transporter binding in depressed patients is due to previous antidepressant drug exposure. In addition, the binding of both [3H]imipramine and the more specific ligand [3H]paroxetine to the platelet 5-HT transporter was compared in drug-free depressed patients and age- and sex-matched normal comparison subjects. METHOD: In the first experiment blood samples were obtained from 12 depressed patients who had never received antidepressant drugs and 12 normal comparison subjects, and platelet 5-HT transporter binding was measured by using [3H]imipramine. In the second experiment blood samples were obtained from 28 drug-free depressed patients and 28 age- and sex-matched comparison subjects, and platelet 5-HT transporter binding was assessed by using both [3H]imipramine and [3H]paroxetine. RESULTS: In the first experiment the never-medicated depressed patients exhibited fewer platelet [3H]imipramine binding sites than did the comparison subjects. In the second experiment the drug-free depressed patients had fewer platelet binding sites for both [3H]imipramine and [3H]paroxetine than did the comparison subjects. CONCLUSIONS: The low number of platelet [3H]imipramine binding sites does not appear to be due to prior antidepressant drug exposure. The Bmax of platelet binding sites for both [3H]imipramine and [3H]paroxetine, ligands used to measure 5-HT transporter binding, is abnormally low in depressed patients.

Antidepressive Agents↗
PubMed1994

Adinazolam sustained-release treatment of panic disorder: a double-blind study.

Two hundred six outpatients with panic disorder and agoraphobia were randomly assigned to receive 4 weeks of treatment with placebo or sustained-release adinazolam under double-blind conditions. Eighty-eight percent of patients receiving drug and 85% of patients receiving placebo remained in the study at week 4. This report describes the "intent-to-treat" analysis of 202 patients who made at least one follow-up visit after randomization at baseline. On the basis of the Clinical Global Impressions-Improvement Scale, 69.7% of the adinazolam-treated patients were much or very much improved compared with 39.6% of the placebo-treated patients at week 4 or end-point (p = 0.0001). At week 4, panic attacks were completely blocked in 57.1% of adinazolam-treated patients and in 39.2% of the placebo-treated patients (p = 0.009). Adinazolam sustained-release treatment was statistically more effective than placebo treatment on measures of global improvement, number of panic attacks, SCL-90 phobia severity, main phobia severity, and anticipatory and general anxiety. No drug-placebo differences were found for overall self-rated phobia severity, unexpected or situational panic attacks, or for work, family, or social disability.

Adult↗
PubMed1993

Dose response relationship between plasma ACTH and cortisol after the infusion of ACTH1-24.

The authors examined the dose response relationship between plasma ACTH and cortisol concentrations after the administration of various doses of ACTH1-24 (0.025 micrograms, 0.125 micrograms, 0.25 micrograms, 1 microgram, 250 micrograms) in dexamethasone-suppressed normal volunteers. A logarithmic dose-response relationship between the dose of ACTH administered and plasma cortisol concentration was found. Although there was considerable variability in plasma ACTH concentrations, there was, however, a definite correlation between area under the curve for ACTH and area under the curve for cortisol after the various doses of ACTH.

Adrenocorticotropic Hormone↗
PubMed1993

Neuroanatomical substrates of depression in the elderly.

The etiology of depression in the elderly is poorly understood. In this study, magnetic resonance imaging was used to evaluate the role of subcortical structures in the pathophysiology of depression in the elderly. Elderly depressed patients were found to have smaller caudate nuclei, smaller putaminal complexes and in increased frequency of subcortical hyperintensities compared with normal, healthy controls. These findings were more pronounced in patients with late-onset depression. Based on these findings, the authors discuss the role of the basal ganglia in the pathophysiology of depression in the elderly.

Age Factors↗
PubMed1993

Hypercortisolemia and hippocampal changes in depression.

Hypercortisolemia is a frequently observed abnormality in patients with major depression. It has been hypothesized that the hippocampus, as a major feedback site for glucocorticoids, is involved in the pathophysiology of hypercortisolemia. Some have in fact posited that the hippocampus is marked by diminished size in depressed patients with hypercortisolemia. We tested this hypothesis by examining the relationship between hippocampal volume, assessed with magnetic resonance imaging, and hypercortisolemia using the dexamethasone suppression test (DST) in a group of 19 depressed patients. No differences in hippocampal volume were observed between patients and control subjects (n = 30). Within the patient group, DST suppressors did not differ from DST nonsuppressors in hippocampal volume. However, a relationship between hippocampal volume and 11 p.m. cortisol concentration was observed after covariance adjustment for age and sex. Furthermore, significant negative correlations were observed between hippocampal volume and both age of depressive onset and number of hospitalizations. The results of this study therefore provide limited support for the hypothesis regarding an essential role of the hippocampus in the neuroendocrine elevation of glucocorticoids in depression.

Adult↗
PubMed1993

Recommendations concerning the costing and management for patients requiring domiciliary ventilation.

Reinstallation back in their own homes of severely disabled people who are ventilator dependent is increasingly becoming a viable trend. Such a development calls for detailed and imaginative planning and negotiations with several agencies. More than a decade of experience in Southport has highlighted the need for early and comprehensive negotiations to ensure that these profoundly disabled people are not denied a quality of life to which they are entitled and which advances in technology has made possible.

Costs and Cost Analysis↗
PubMed1993

Profile of depressive symptoms in younger and older medical inpatients with major depression.

OBJECTIVE: To examine and compare the profile of cognitive symptoms, somatic symptoms, and somatic complaints in younger and older medical inpatients diagnosed with major depressive disorder (MDD). DESIGN: Cross-sectional cohort. PATIENTS AND SETTING: Male patients aged 20-39 years (n = 116) and aged 70-102 years (n = 332), consecutively admitted to the medical and neurological services of a VA medical center, underwent psychiatric evaluations for depression. MEASUREMENTS: Depressive symptoms were measured using the observer-rated Hamilton Depression Scale and the self-rated Geriatric Depression Scale using an "inclusive" approach (symptoms rated regardless of etiology). Data on 12 common somatic complaints were also collected. Clinical diagnoses of MDD were made by a psychiatrist based on the Diagnostic Interview Schedule and other psychiatric and physical health data. RESULTS: After controlling for severity of medical illness, functional status, and alcohol use, symptoms that discriminated MDD best among younger men were loss of interest, feelings of guilt or of being a burden, suicidal thoughts, and depressed mood (primarily cognitive and affective symptoms). Among older men, loss of interest, insomnia, suicidal thoughts, and hypochondriasis most strongly differentiated depressed from non-depressed patients (mixture of cognitive and somatic symptoms); fatigue, weight loss, genital symptoms, and somatic anxiety were weakly related or unrelated to MDD. Number of somatic complaints (headache, dizziness, palpitations, etc.) helped differentiate patients with MDD; although equally common among depressed young and older patients, a distinct pattern of complaints emerged in each age group. CONCLUSIONS: Cognitive symptoms of depression can help to distinguish medical inpatients with and without MDD. In older adults, however, somatic symptoms cannot be ignored and may be more important for diagnosing MDD than previously realized. These findings will help clinicians identify patients with MDD and differentiate them from non-depressed patients with medical illness.

Activities of Daily Living↗
PubMed1993

In vivo quantitation of basal ganglia and thalamic degenerative changes in two temporal lobectomy patients with affective disorder.

The authors examined the brain magnetic resonance imaging scans of two epilepsy patients who had temporal lobectomies, one on the right and one on the left, with postoperative symptoms of affective disorders. Degenerative changes of ipsilateral thalamus and putamen after surgery, with coincident affective disorder, were noted. The authors discuss a possible relationship between postlobectomy degeneration and depression.

Adult↗
PubMed1993

The role of nuclear magnetic resonance imaging in psychiatric research.

Magnetic resonance imaging (MRI) has become an important tool in the investigation of cerebral abnormalities associated with psychiatric illnesses. There are a number of benefits of investigating psychiatric illness with MRI, which is superior to computed tomography scanning. MRI has been used to study neurologic deficits seen in schizophrenia, affective disorders, dementia, and more recently, anxiety disorders. Magnetic resonance spectroscopy offers a new investigational technique that adds functional information to the structural changes seen with standard MRI scanning. This review highlights the current data in living human subjects that demonstrate structural changes in psychiatric disorders using MRI, including recent studies of the anxiety disorders.

Aged↗
PubMed1993

Magnetic resonance spectroscopy in social phobia: preliminary findings.

Proton localized magnetic resonance spectroscopy was studied in 20 social phobics and 20 age- and sex-matched controls. Stimulated Echo Acquisition Mode volume element localization was used with chemical shift imaging. Choline and creatine signal-to-noise ratios (SNRs) were significantly lower in social phobia than in controls in subcortical, thalamic, and caudate areas. In the social phobic group, N-acetylaspartate (NAA) SNR was significantly lower in cortical and subcortical regions, and ratios of NAA to other metabolites were lower in social phobia. Choline, creatine, and NAA SNRs were inversely correlated to total social phobia and fear symptoms, as measured by the Brief Social Phobia Scale, in the thalamic and noncortical gray areas. In a small number of patients who received clonazepam, posttreatment SNRs generally increased relative to baseline. Our results suggest a promising place for magnetic resonance spectroscopy in social phobia and also indicate potential pharmacodynamic uses of this technique.

Adult↗
PubMed1993

Diminished subcortical nuclei volumes in Parkinson's disease by MR imaging.

Parkinson's disease (PD) is associated with changes in the substantia nigra, which communicates with subcortical nuclei. This study investigates subcortical nuclei volume in PD in vivo by magnetic resonance (MR) imaging. Caudate, putaminal, and thalamic nuclei were measured on axial MR images using a point counting method and systematic sampling. PD patients (n = 21) had significantly smaller subcortical nuclei than age- and sex-matched controls (p < 0.001) and depressed patients (p < 0.01). The decline in PD was not correlated with age, sex, or cortical volume. Depressed patients had significantly smaller caudate and putaminal nuclei than controls (p < 0.05 and 0.01, respectively) but thalamic nuclei were not significantly different. Caudate, putaminal, and thalamic nuclei volumes of controls were significantly negatively correlated with age (r = -0.58, p < 0.01; r = -0.77, p < 0.001; r = -0.57, p < 0.01, respectively). Depressed subjects demonstrated a negative trend. Volumetric measurements by MR imaging may be a useful in investigating the role of the basal ganglia in neurological disorders.

Caudate Nucleus↗
PubMed1993

Relationship of past depressive episodes to symptom severity and treatment response in panic disorder with agoraphobia.

BACKGROUND: Many investigators have reported that panic disorder (PD) patients with comorbid major depression (MD) have more severe symptoms and a poorer response to treatment than patients with PD alone. It is not known if this is due to a distinct and more serious underlying disorder in these patients or simply a result of the simultaneous presence of the two disorders. METHOD: Nondepressed patients presenting for treatment of panic disorder with agoraphobia (PDA) were studied before treatment (N = 180) and after 4 weeks of treatment with adinazolam sustained release (N = 89) or placebo (N = 91). Twenty-nine percent (N = 53) of the patients had a past history of MD. Symptom severity and treatment outcome were compared in patients with primary, secondary, single, recurrent, or no past MD. RESULTS: There were no consistent differences in symptom severity or treatment outcome in patients with a past history of primary, secondary, or single episode MD compared with patients with no history of MD. However, a small number of patients with history of recurrent MD exhibited consistently greater symptom severity and poorer response to treatment than patients with no history of MD. CONCLUSION: The greater severity and worse outcome of comorbid PD and MD observed in earlier studies are more likely due to the simultaneous presence of the two disorders than to a more serious and enduring underlying disorder. However, our results suggest that recurrent MD may indicate a more serious condition in patients with PDA. This possibility warrants further study.

Adult↗