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Biomedical subjects

B R Nakra

Publications and source records attributed to B R Nakra.

At least 19 recordsLinked to original sources
PubMed1994

Drinking behavior and vasopressin responses to hyperosmolality in Alzheimer's disease.

Individuals with Alzheimer's disease (AD) have been shown to have abnormalities in response to fluid restriction. Twelve subjects with AD and ten elderly controls underwent overnight fluid restriction followed by measurement of plasma and urine vasopressin and serum osmolality. Estimates of "thirst" were determined after one hour of ad libitum water intake. All subjects were tested with a Mini-Mental State Examination (MMSE) and Global Deterioration Scale (GDS). Individuals with AD had a greater degree of overnight dehydration than the elderly control group (serum osmolality 310 +/- 1 vs. 305 +/- 1 mosmol/kg, p = 0.02). There was no difference between the groups in the plasma or urinary levels of vasopressin. There was a direct correlation (r = 0.45, p = 0.03) of the amount of water intake as a measure of "thirst" with the MMSE score as a measure of cognitive functioning. Individuals with advanced cognitive impairment may be at risk of dehydration due to loss of protective "thirst" responses with secondary complications of dehydration.

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PubMed1992

A double-blind comparison of the effects of temazepam and triazolam on residual, daytime performance in elderly insomniacs.

Benzodiazepine hypnotic medications are widely prescribed for elderly patients, but there is a paucity of information available concerning the residual cognitive and psychomotor (the morning-after) effects of these drugs. We compared two commonly used hypnotics--temazepam and triazolam--in a double-blind, placebo-controlled, single-dose study with community-dwelling healthy elderly with a DSM-III-R diagnosis of primary insomnia. Forty-five subjects over the age of 65 (mean age 72.23, SD = 4.44) qualified for the study. Subjects were randomly assigned to one of five treatment groups (placebo, triazolam 0.125 mg., triazolam 0.25 mg., temazepam 15 mg., and temazepam 30 mg.). Neuropsychological testing was completed at baseline and 12-14 hours after the dosing. Patients were evaluated with a variety of tests that measured attention, concentration, motor speed, immediate memory, and learning of new information. Separate repeated measured analyses of variance were performed to assess the significant changes among the five treatment groups. We found improved performance or no change in all the measures for all medication groups except for impairment of performance on a serial learning task for both high-dose medication groups. The significance of these results and the need for further research in elderly insomniacs is discussed.

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PubMed1992

The effect of a single low dose of trihexyphenidyl on memory functioning in the healthy elderly.

Medications with anticholinergic properties, when taken at therapeutic doses, are known to adversely affect memory functioning in young adults and the elderly. However, their impact at lower doses in geriatric persons has been less thoroughly studied. We investigated the impact of a single 2-mg dose of trihexyphenidyl on memory functioning in 20 healthy elderly subjects using a within-subjects, double-blind comparison with a placebo. Memory functioning was evaluated using subtests of the Wechsler Memory Scale. Subjects also rated the perceived impact of medication on their performance following memory testing. Results indicated that the single 2-mg dose of trihexyphenidyl produced impaired performance on measures of immediate and half-hour delayed recall of complex verbal and visual material when compared to the placebo condition. However, differences were not found on several other memory measures, including general orientation, attention-concentration, and learning of word associations. The significance of these selective memory deficits and suggestions regarding future research are discussed.

Aged↗
PubMed1991

Insomnia in the elderly.

Insomnias lead the list of sleep disorders in the elderly. The differential diagnosis includes poor sleep habits, medical and psychiatric disorders, and drug interactions. Effective treatment includes sleep hygiene education and avoidance of substances known to interfere with sleep. In general, anticholinergic agents, antihistamines and long-half-life benzodiazepines should be avoided as hypnotic agents in the elderly. Safer therapeutic options include relaxation therapy and the short-half-life benzodiazepines without active metabolites.

Aged↗
PubMed1990

Geriatric psychiatry consultations in a university hospital.

A review was conducted of the records of 147 patients above the age of 60 in a 350-bed general university hospital for whom a request for consultations was made over a two-year period by a geriatric psychiatry division in a department of psychiatry. Findings were compared with those obtained by Mainprize and Rodin and by Ruskin. Most referrals in the present study were from internal medicine as they were in the other two studies. The principal reason for referrals in this and in Mainprize and Rodin's study was depression (48% and 37%, respectively) but not in Ruskin's study (10%). The primary DSM-III-R diagnoses of the referred patients in this study were affective disorder (27%), adjustment disorders (26%), and dementia (22%). Affective disorder was also the most frequent diagnosis in Ruskin's study. Psychotropic medication was the most frequently cited recommendation in all three studies.

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PubMed1989

Vasopressin response to dehydration in Alzheimer's disease.

Alzheimer's disease is a progressive deterioration of neuropsychological functioning. One of the main neuropathological correlates of the disease is a drop-out of cholinergic neurons within the central nervous system. The neuropeptide that is responsible for water homeostasis and defense against dehydration, vasopressin, is also under direct cholinergic control. Several studies have suggested that in Alzheimer's disease there has been a trend toward lower vasopressin levels than in age-matched controls. In order to improve discrimination of normal from diminished vasopressin levels, nine subjects with Alzheimer's disease (mean age 65 +/- 2 years) and nine age- and sex-matched controls (68 +/- 3 years) underwent a mild provocative challenge of overnight fluid restriction. Individuals with Alzheimer's disease had a greater degree of dehydration, with overnight serum osmolality of 313 +/- 4 vs 300 +/- 3 Mosmol/kg, P = .01, and diminished "thirst" as measured by water ingested in one hour of ad libitum water intake. Eight of the nine with Alzheimer's disease had levels of vasopressin which, by extrapolation, appear to be subnormal for their serum osmolalities, whereas seven of the nine control subjects has vasopressin levels within or above the reference range (P less than .05). Elderly individuals with Alzheimer's disease may be at increased risk of dehydration during periods of fluid restriction due to the loss of normal physiological responses of "thirst" and vasopressin secretion.

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PubMed1987

Phenylethanolamine N-methyltransferase activity is decreased in Alzheimer's disease brains.

Phenylethanolamine N-methyltransferase (PNMT) is the rate-limiting enzyme involved in the synthesis of epinephrine and a specific marker for epinephrine neurons. We have previously described the stability of this enzyme in a variety of pre- and postmortem conditions in human brain autopsy specimens and demonstrated its presence in areas of the human brain that are associated with memory and attention. We now report on 5 patients with Alzheimer's disease (AD) who had a decrease in PNMT activity of 37 to 48% in areas of the brain affected by the disease but not in the cerebellum, an area of the brain unaffected by the disease. The degree of decrease in PNMT activity in the hippocampus correlated significantly with the degree of dementia. We have provided direct immunochemical evidence that the decrease in PNMT activity in AD is due to the loss of this specific enzyme protein.

Aged↗
PubMed1986

Management of anxiety in the elderly.

Clinicians need to be aware of the cardinal manifestations of clinical anxiety in their geriatric patients. A variety of psychotherapeutic, behavioral, and chemical interventions can effectively and safely treat anxiety in geriatric patients and thereby greatly diminish morbidity and mortality.

Aged↗
PubMed1980

Pimozide as an adjuvant to maintenance therapy in chronic schizophrenia.

An open, 12-week study of pimozide (8 mg per day) used concurrently with previous maintenance therapy was carried out to investigate improvements in the social behaviour of 20 chronic schizophrenics. Ward behaviour, work habits and mental status all showed statistically significant improvement after 8 weeks of treatment. The incidence of side-effects was low.

Adult↗
PubMed1977

Steady-state serum concentrations of dothiepin and northiaden after two dosage regimens of dothiepin hydrochloride (Prothiaden).

Five healthy volunteers took part in a crossover study which examined the serum concentrations of dothiepin and northiaden after a 25 mg three times a day and a 75 mg once a day dosage regimen of Prothiaden. The inter-individual variation of serum levels was large after either schedule which is to be expected with this group of drugs. The minimum steady-state level of dothiepin tended to be lower after the single daily dose, but the differences were small and not statistically significant. The approximate maximum steady-state levels of dothiepin showed large intra-and inter-subject variation and no obvious trend. The values of the desmethylated metabolite, norhiaden, tended to follow the dothiepin concentrations but were lower than the parent drug. Average steady-state levels tended, with one exception, to be very similar after both regimens with no evidence with no evidence fo any trend when comparing the two regiments. The study showed that the two regimens yielded similar steady-state serum concentrations both of drug and metabolite but inter-individual differences were large.

Adult↗
PubMed1977

Preliminary evaluation of a new psychotropic drug, lenperone, in the treatment of acute schizophrenia.

An open trial of a new psychotropic drug, lenperone, was carried out in 10 patients with acute schizophrenia. The duration of treatment was 28 days and the maximum dose administered was 60 mg per day. A pronounced antipsychotic effect was seen in half of the patients, although all 10 patients showed a pharmacological response to the drug. The incidence of side-effects was low. Haematological, biochemical and electrocardiographic tests failed to demonstrate any abnormality due to treatment.

Acute Disease↗
PubMed1977

Amitriptyline and weight gain: a biochemical and endocrinological study.

A study was carried out in 6 healthy volunteers to test the hypothesis that weight gain associated with amitriptyline treatment may be due to hypoglycaemia caused by increased circulating blood insulin. Subjects were treated with 50 mg amitriptyline b.d. for 28 days. Estimations made of serum levels of amitriptyline and its metabolite nortriptyline showed a steady state by the 10th day. No significant weight-gain was observed in any of the volunteers, although 2 reported an increase in appetite. There were no significant differences in any of the glucose tolerance curves, fasting or peak insulin levels or in the glucose/insulin curves for Days 0, 14 and 28.

Amitriptyline↗