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Biomedical subjects

A Roy

Publications and source records attributed to A Roy.

At least 379 records · Page 21Linked to original sources
PubMed1987

Immunological characterization of soluble peroxidases from rat tissues including preputial gland.

A highly active soluble peroxidase has been identified in the preputial gland of rats and characterized immunologically along with other soluble peroxidases of a number of rat tissues such as submaxillary gland, exorbital lacrimal gland and also of the uterine fluid of the estrogen treated rats. All these peroxidases have the native molecular weight around 73K as determined by gel filtration on Sephadex G-150. An antiserum raised against the pure bovine lactoperoxidase interacts with all these soluble peroxidases and immunoprecipitates the enzyme activity in a similar fashion when titrated against varied concentration of the antiserum. Following electrophoretic transfer to nitrocellulose by Western blotting, the antiserum crossreacts with the preputial, submaxillary and lacrimal gland protein of molecular weight around 73K and with the uterine fluid protein of molecular weight of 80K. An additional crossreacting protein of molecular weight of 80K is also evident in the lacrimal gland. All these enzyme preparations, however, contain another immunoreactive protein of molecular weight of about 64K. While 73-80K molecular weight interacting proteins may represent different forms of peroxidase, presumably with varied carbohydrate moieties, 64K molecular weight protein may be a precursor of the peroxidase which after posttranslational modification such as heme conjugation and glycosylation leads to formation of native enzyme. Rat harderian gland, unlike bovine origin, does not contain any detectable peroxidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Nutritive value of acetylated and hydrolysed rapeseed proteins in rats.

Acetylated, hydrolysed and unmodified rapeseed proteins were compared to casein for nutritive value as determined by net protein ratio (NPR) and nitrogen apparent digestibility coefficient (ADC). The NPR and nitrogen ADC values of rapeseed proteins did not change significantly (P less than 0.05) after hydrolysis but decreased significantly (P less than 0.05) after 30% and 70% acetylation. Acetylation (30%) followed by protein hydrolysis decreased significantly (P less than 0.05) the NPR value but increased significantly (P less than 0.05) the nitrogen digestibility compared to the control and unmodified rapeseed proteins. Casein gave the highest value (P less than 0.05) for NPR and nitrogen ADC. Modification of rapeseed proteins significantly (P less than 0.05) decreased the nutritive value, and the effect was more pronounced with increasing level of acetylation.

Acetylation↗
PubMed1987

Plasma norepinephrine responses to cold challenge in depressed patients and normal controls.

Thirty depressed patients were compared with 39 controls for their plasma norepinephrine (NE) levels in relation to a cold challenge (placing a hand in ice cold water for 1 minute). Depressed patients showed significantly higher plasma NE levels than controls. Unipolar, but not bipolar patients, had significantly higher plasma NE levels than age- and sex-matched controls. Unipolar melancholic patients who were nonsuppressors on the dexamethasone suppression test showed a strong trend to have higher plasma NE levels than suppressors. These results are further evidence that the NE system is dysregulated in depression.

Bipolar Disorder↗
PubMed1987

Cerebrospinal fluid corticotropin-releasing hormone in depression: relationship to noradrenergic function.

We investigated the neurotransmitter regulation of corticotropin-releasing hormone (CRH). Among 21 depressed patients cerebrospinal fluid (CSF) levels of CRH significantly correlated with urinary outputs of norepinephrine and its major metabolites, and there were trends for significant correlations with both CSF and plasma levels of norepinephrine. These results suggest that CRH may be associated with the dysregulation of the norepinephrine system that is found in desperation.

Adult↗
PubMed1987

Reduced central serotonin turnover in a subgroup of alcoholics?

We review cerebrospinal fluid (CSF) studies suggesting on association between low CSF levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAAA) and suicidal and impulsive behaviour and alcoholism. Relatively high percentages of alcoholics attempt and commit suicide and have impulsive antisocial personality disorder. Therefore, we suggest that there may be a sizable subgroup of alcoholics who have a reduced central serotonin turnover.

Aggression↗
PubMed1987

Cerebrospinal fluid neuropeptide Y in depression and schizophrenia.

Neuropeptide Y (a recently discovered brain peptide that is colocalized with norepinephrine within some adrenergic central nervous system neurons) was measured in the cerebrospinal fluid (CSF) from patients with major affective disorder, chronic schizophrenia, and in normal volunteers. No differences between diagnostic groups were found, suggesting that if this neuropeptide is involved in the pathogenesis of these disorders, an abnormality is not detectable in the CSF.

Biomarkers↗
PubMed1987

SQUID measurement of metalloprotein magnetization. New methods applied to the nitrogenase proteins.

New techniques have been developed to exploit the sensitivity of a commercial SQUID susceptometer in the study of the magnetization of metalloproteins. Previous studies have ignored both the slow relaxation (hours) of spin I = 1/2 nuclei and residual ferromagnetic impurities in sample holders. These potential sources of noise were at or below the sensitivity of previous instruments. With these noise sources under control, one can now decrease the protein concentration by a factor of ten. In addition careful characterization of the frozen magnetization sample, including the use of a multi-instrument holder for combined study of the magnetization sample with Mössbauer spectroscopy, is required for reliable interpretation of the data in the face of paramagnetic impurities common to metalloprotein samples. Many previous magnetic studies of metalloproteins have been carried out in the Curie region. Saturation magnetization studies down to 1.8 K and up to 5 T can determine zero-field splitting parameters in addition to the spin and exchange coupling parameters measured in previous studies at lower fields and higher temperatures. Applications of these techniques to the study of the nitrogenase proteins of Azotobacter vinelandii are presented as examples.

Azotobacter↗
PubMed1987

Intestinal obstruction as a cause of death in the mentally handicapped.

This paper reviews the occurrence of symptoms of intestinal obstruction in mentally handicapped people. A retrospective study was done on all residents dying in mental handicap hospitals over a 7-year period. It was noticed that people dying of intestinal obstruction were younger, male, gave a history of constipation, other gastrointestinal problems and dietary indiscretion.

Adolescent↗
PubMed1987

Plasma dopamine-beta-hydroxylase in depressed patients and controls.

We measured plasma dopamine-beta-hydroxylase (DBH) activity in depressed patients and normal controls. There were no significant differences for plasma DBH activity between depressed patients and controls nor between melancholic or nonmelancholic depressed patients nor between depressed patients who were nonsuppressors or suppressors according to the dexamethasone suppression test. Among the depressed patients plasma DBH activity correlated significantly with extraversion scores on the Eysenck Personality Questionnaire.

Adult↗
PubMed1987

Neuroleptic responsivity of negative and positive symptoms in schizophrenia.

The authors prospectively examined the effects of double-blind, placebo-controlled neuroleptic withdrawal and administration on ratings of negative and positive symptoms in 19 young patients with chronic schizophrenia. Negative symptoms were significantly reduced by neuroleptic treatment, and negative and positive symptoms demonstrated similar patterns of reduction and exacerbation during neuroleptic treatment and withdrawal, respectively. The changes in negative and positive symptoms induced by neuroleptic treatment and withdrawal were not significantly correlated, however. The negative and positive symptom profiles of individual patients were significantly altered by neuroleptic treatment, indicating limitations to the cross-sectional classification of patients on the basis of predominance of one or the other symptom group. The authors discuss implications for the neurobiological underpinnings of negative and positive symptoms.

Adult↗
PubMed1987

CSF corticotropin-releasing hormone in depressed patients and normal control subjects.

The authors studied CSF corticotropin-releasing hormone (CRH) and plasma cortisol in 22 depressed patients and 18 normal control subjects. CRH levels were similar in the two groups. Depressed patients who were nonsuppressors on the dexamethasone suppression test had significantly higher levels of CRH than suppressors did. The depressed patients' CRH levels were significantly correlated with 4:00 p.m. postdexamethasone plasma cortisol levels. While the inclusion of a depressed patient with an outlier CRH value resulted in the loss of statistical significance for both of these findings, the authors suggest that these results support the hypothesis that hypercortisolism in depressed patients in part reflects a defect at or above the hypothalamus, resulting in hypersecretion of CRH.

Adult↗
PubMed1987

Five risk factors for depression.

Significantly more of 300 patients with non-endogenous depression compared with 300 matched controls were unemployed and had a poor marriage before the onset of depression, had a first-degree relative who had been treated for depression, had experienced separation for one year or more from a parent before 17 years of age and had three or more children under 14 years of age at home. However, significantly more of 44 patients with endogenous depression, than their 46 controls, also had a poor marriage before the onset of depression and 43% of them had a first-degree relative who had been treated for depression. Thus a family history of depression and a poor marriage before the onset of depression are associated with both non-endogenous and endogenous depression but unemployment, separation for one year or more from a parent before 17 years of age, and having three or more young children at home may be risk factors for non-endogenous depression.

Child Rearing↗
PubMed1986

Responses to corticotropin-releasing hormone in the hypercortisolism of depression and Cushing's disease. Pathophysiologic and diagnostic implications.

Primary depression can be associated with substantial hypercortisolism, thus prompting some researchers to suggest that depression shares pathophysiologic features with Cushing's disease. Clinically, depression can be difficult or impossible to distinguish from mild or early Cushing's disease that is associated with depressive features. The purpose of this study was to evaluate whether the pituitary-adrenal responses to ovine corticotropin-releasing hormone could help to clarify the mechanism of hypercortisolism in depression and in Cushing's disease and to assist in the differential diagnosis of these disorders. As compared with controls (n = 34), depressed patients (n = 30) had basal hypercortisolism (P less than 0.001) that was associated with attenuated plasma ACTH responses to ovine corticotropin-releasing hormone (P less than 0.001). This indicates that in patients with depression, the corticotroph cell in the pituitary responds appropriately to the negative feedback of high cortisol levels. In contrast, patients with Cushing's disease (n = 29) had plasma ACTH hyperresponsiveness to ovine corticotropin-releasing hormone (P less than 0.001), despite basal hypercortisolism (P less than 0.001), which indicates a gross impairment of the mechanism by which cortisol exerts negative feedback on the pituitary. Less than 25 percent of the patients with depression or Cushing's disease had peak ACTH responses that overlapped. We conclude that the pathophysiologic features of hypercortisolism in depression and Cushing's disease are distinct in each of the disorders and that the ovine corticotropin-releasing hormone stimulation test can be helpful in their differential diagnosis.

Adrenocorticotropic Hormone↗
PubMed1986

Cerebrospinal fluid monoamine and monoamine metabolite levels and the dexamethasone suppression test in depression. Relationship to life events.

The cerebrospinal fluid levels of norepinephrine and six monoamine metabolites were measured in 23 patients meeting DSM-III criteria for major depressive episode, 15 of whom also met criteria for melancholia. Life events during the six-month period before the onset of depression were recorded using Paykel's method. There was no difference in Hamilton depression ratings between patients with life events and those without. However, depressed patients who did not have a life event in the six months before the onset of depression had significantly lower levels of the dopamine metabolite homovanillic acid and the serotonin metabolite 5-hydroxyindoleacetic acid than those with life events. The incidence of nonsuppression on the dexamethasone suppression test was also greater in patients with a major depressive episode who did not have an undesirable life event than in those who did. Thus, the presence or absence of life events led to a separation into biologically distinct groups.

Adult↗