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Biomedical subjects

M Hammer

Publications and source records attributed to M Hammer.

At least 127 records · Page 7Linked to original sources
PubMed1985

Cerebrospinal fluid and plasma vasopressin during short-time induced intracranial hypertension.

The response of plasma and ventricular cerebrospinal fluid vasopressin concentration to short-time induced intracranial hypertension was studied in 8 patients with hydrocephalus, defined as ventricular enlargement on computerized tomography. In connection with measurement of conductance to cerebrospinal fluid outflow, the concentration of vasopressin in plasma and cerebrospinal fluid was measured during perfusion at a low (less than 10 mmHg) and at a high (greater than 20 mmHg) intraventricular pressure level. Mean plasma vasopressin concentration was increased from 2.4 +/- 0.4 pg/ml (SEM) during perfusion at the low pressure level to 4.2 +/- 0.8 pg/ml (p less than 0.01) at the high pressure level. The cerebrospinal fluid concentrations of vasopressin at the low and high intraventricular pressure were 1.2 +/- 0.1 pg/ml and 1.7 +/- 0.2 pg/ml (p less than 0.05), respectively. However, only half of the patients responded to the increase in intraventricular pressure with an increase in cerebrospinal fluid vasopressin concentration exceeding 50%. The results of the present study suggest that an increase in the intracranial pressure might be a stimulus for vasopressin release in both the blood and the cerebrospinal fluid.

Aged↗
PubMed1985

24-hour cerebrospinal fluid levels of vasopressin in hydrocephalic patients.

The variation in vasopressin concentrations of ventricular cerebrospinal fluid and plasma throughout a 24-h period was studied in 10 patients with hydrocephalus. In 6 control patients, the diurnal variation in plasma vasopressin concentrations was studied. Vasopressin concentrations were determined by radioimmunoassay in plasma and in extracted and unextracted cerebrospinal fluid. Cortisol and osmolality in plasma were also measured. Vasopressin concentrations measured in extracted cerebrospinal fluid showed only small intra- and interindividual variation, while the corresponding values for unextracted cerebrospinal fluid were 2-5-fold higher and showed more variation. Plasma vasopressin concentrations varied considerably throughout the 24-h period in the individual hydrocephalic patient and between the patients. The pattern of variation was inconstant with no circadian rhythm, and the variation was not related to any changes in plasma osmolality, blood pressure or intracranial pressure. In some of the patients, the normal diurnal pattern of variation in plasma cortisol was broken, however, without a relation to the observed fluctuations in vasopressin concentrations. The abnormal variation of plasma vasopressin and cortisol was considered to reflect stress in connection with the intracranial pressure monitoring procedure. In the control patients, plasma vasopressin showed only small variations and plasma cortisol showed a normal diurnal rhythm. It is concluded that cerebrospinal fluid vasopressin concentration in patients with hydrocephalus is very constant throughout the day, even when plasma vasopressin concentrations show marked episodic increases. Thus, a circadian rhythm in the cerebrospinal fluid vasopressin concentration, as reported in several animal species, could not be confirmed in these patients.

Adult↗
PubMed1985

Bed rest and increased diuretic treatment in chronic congestive heart failure.

To elucidate the effect of bed rest used as an adjunct to increased diuretic treatment, twelve patients with chronic congestive heart failure (CHF) had a 50% increase in loop diuretic dosage and were allocated to either continuous bed rest or bed rest during nights only. The 24-hour bed rest group reduced their weight significantly (mean +/- SEM: 2.00 +/- 0.79 kg, P less than 0.001), whereas the night bed rest group had no significant weight reduction (1.10 +/- 0.37 kg, 0.1 less than P less than 0.2) during three days of observation. Furthermore, the 24-hour bed rest group had a significantly increased diuresis (P less than 0.05) during the first day of the study and a tendency towards increased natriuresis. The cumulated diuresis for the two groups (24-hour bed rest versus night bed rest) during the three days of study were 7773 +/- 700 ml and 5861 +/- 909 ml (0.05 less than P less than 0.1), respectively. Plasma concentrations of adrenaline, noradrenaline, renin and aldosterone were increased, as measured in the supine position. No significant differences were found between the two groups. Plasma concentrations of antidiuretic hormone were within normal limits. In conclusion, continuous bed rest is a reasonable adjunct to diuretic treatment in patients with CHF.

Adult↗
PubMed1985

Chlorpromazine increases the lowered response to antidiuretic hormone in rats with lithium-induced diabetes insipidus.

The interaction between chlorpromazine (CPZ) and lithium on renal concentrating ability was studied in rats fed a Li-containing diet for 8 weeks (plasma-Li 0.6-0.7 mmol/l). CPZ (15 mg/kg daily orally) reduced the polydipsia and increased the ability to concentrate the urine upon water deprivation in rats treated with lithium. CPZ also reduced systolic blood pressure, but had no effect on the glomerular filtration rate or plasma levels of arginine vasopressin (AVP) in hydrated rats treated with lithium. However, CPZ prevented the rise in plasma AVP levels observed in lithium-polyuric rats in response to dehydration. During anaesthesia CPZ partially restored the impaired anti-diuretic response to exogenous AVP in rats treated with lithium. CPZ had no influence on plasma-Li levels in rats treated with lithium. It is suggested that CPZ by unknown mechanisms interferes with the effects of lithium on the water permeability response to AVP.

Animals↗
PubMed1985

Cerebrospinal fluid vasopressin in neurological and psychiatric disorders.

Vasopressin was determined in CSF and plasma of 243 patients with different neurological and psychiatric disorders, including control patients. CSF vasopressin was significantly higher in patients with high pressure hydrocephalus, intracranial tumour, benign intracranial hypertension, intracranial haemorrhage, ischaemic stroke, and craniocerebral trauma. In patients with primary degenerative dementia, CSF vasopressin was lower than in control patients. Among patients with psychiatric disorders, CSF vasopressin was increased in manic patients, while in patients with depression CSF concentration of this hormone did not differ from that found in controls. However, an increase in CSF vasopressin level was found in patients recovering from a depression. The clinical significance of changes in CSF vasopressin concentrations in groups of patients with neurological and psychiatric disorders is still unknown.

Adult↗
PubMed1985

Vasopressin in plasma and ventricular cerebrospinal fluid during dehydration, postural changes, and nausea.

The responses of plasma and ventricular cerebrospinal fluid (CSF) vasopressin concentration to dehydration, postural changes, and induction of nausea were studied in 21 patients with hydrocephalus of various etiology. The 24-h dehydration test evoked a significant increase in plasma osmolality and vasopressin concentration, whereas the concentration of vasopressin in CSF was unchanged. Head-up tilt to 50 degrees for 45 min with a tilt bed resulted in a modest increase of plasma vasopressin in patients who did not develop presyncopal symptoms, but no changes were seen in CSF vasopressin. Induction of nausea by subcutaneously injected apomorphine provoked a marked (20- to 50-fold) rise in plasma vasopressin concentration within 15 min, and the plasma concentration was significantly increased above base-line values for 60-120 min. Despite the prolonged period of high plasma vasopressin concentration CSF vasopressin was not influenced by the apomorphine injection. The findings suggest that the concentration of vasopressin in the CSF is controlled by mechanisms other than the well-known osmotic and nonosmotic stimuli of vasopressin release into the blood.

Adult↗
PubMed1985

Cerebrospinal fluid vasopressin--changes in depression.

Cerebrospinal fluid (CSF), thyrotropin releasing hormone (TRH), CSF-vasopressin (AVP), plasma-AVP, CSF-osmolality, plasma-osmolality, CSF-adrenaline (A) and -noradrenaline (NA) were measured in psychiatric patients and controls. Psychiatric patients were classified according to ICD-9 and grouped into endogenous depression, non-endogenous depression, mania and schizophrenia. The depressive groups were classified according to the Newcastle Rating Scale for Depression 1965. Severity of disease was quantified by BRMES, BRMS and BPRS. No difference in CSF-TRH levels was seen among the different diagnostic groups and controls. A positive correlation between CSF-TRH and CSF-A was demonstrated. CSF-AVP concentrations were significantly lowered in both endogenous and non-endogenous depression; no correlation with CSF-A or -NA was seen. Neither did any difference between plasma levels of AVP, plasma-osmolality or CSF-osmolality appear among the groups investigated.

Adolescent↗
PubMed1985

Cerebrospinal fluid vasopressin as a marker of central nervous system metastases from small-cell bronchogenic carcinoma.

Vasopressin (ADH) was measured in CSF and plasma in 75 evaluable patients with known or suspected CNS metastases from small-cell bronchogenic carcinoma (SCBC), and in 66 control patients having neither malignant disease nor organic CNS disease. The presence of CNS metastases was confirmed or excluded on the basis of computed tomographic scans, neurologic examination, and autopsy. Twenty-four of the 75 patients had no CNS metastases. Ten of the 51 patients with CNS metastases had leptomeningeal carcinomatosis (MC). CSF-ADH was significantly increased in patients with MC (P less than .05), but not in patients having exclusively parenchymatous CNS metastases. Taking 2 pg/mL (95th percentile of control patients) as the upper limit of normal, 15 SCBC patients had elevated CSF-ADH, including 12 patients with CNS metastases and six patients with MC. The CSF-ADH to plasma ADH ratio was significantly increased in patients with CNS metastases (P less than .05). Patients without CNS metastases had a ratio less than or equal to 0.8 whereas the ratio was greater than 0.8, in 21 of the 51 patients with CNS metastases. The positive and negative predictive values with 95% confidence limits were 84% to 100% and 31% to 59%, respectively. Patients with inappropriate secretion of ADH (SIADH) constituted a significantly greater proportion of patients with elevated CSF-ADH than of patients with normal CSF-ADH levels (P less than .05). In addition, patients with SIADH constituted a significantly greater proportion of patients with MC than of patients with parenchymatous metastases (P less than .05). The diagnostic application of these findings is limited because of the large number of false-negative results, but it may prove to be of value in conjunction with the measurement of other tumor markers.

Carcinoma, Bronchogenic↗
PubMed1985

Aldosterone response to modulation of potassium in patients on dialysis or with essential hypertension.

This investigation demonstrates in patients with essential hypertension an abnormal response of the adrenal glands to modulation of potassium metabolism by infusion of insulin-glucose. Similar results have been reported in anephric patients, while the inverse response of non-nephrectomised patients on dialysis corresponded to that of normal subjects. It is suggested that the abnormal response of patients with essential hypertension may be of importance to the understanding of the pathogenesis of this important disease.

Adult↗
PubMed1985

Peroral treatment of diabetes insipidus with a polypeptide hormone analog, desmopressin.

In the present study nine diabetes insipidus patients were treated with desmopressin (DDAVP) tablets. All patients had a significant reduction of their polyuria after a peroral dose of 50 micrograms DDAVP. During a 6-day trial, a peroral treatment with two or three daily peroral doses of DDAVP controlled their polyuria. A dose-response study in five of the patients indicated that peroral DDAVP doses as small as 10 micrograms have effects on renal concentrating ability. A log-linear relationship was found between DDAVP doses and maximal urine osmolalities and duration of antidiuresis. Measurements of plasma DDAVP concentrations after peroral DDAVP revealed a linear relationship between amounts of DDAVP absorbed and dose, but with great interindividual differences. The results indicate that graded renal response occur at plasma concentrations of DDAVP between 1 and 5 pg/ml. The results of this study and the assessment by the patients of the treatment indicate that peroral therapy with DDAVP may be an attractive alternative to traditional intranasal administration of the drug.

Administration, Oral↗
PubMed1984

Cerebrospinal fluid vasopressin and increased intracranial pressure.

Cerebrospinal fluid and plasma vasopressin were measured in patients with cerebral disorders associated with varying levels of elevated intracranial pressure. The mean cerebrospinal fluid vasopressin concentration was significantly increased in patients with pseudotumor cerebri (2.0 +/- 0.2 [SEM] pg/ml), intracranial tumor (2.3 +/- 0.4 pg/ml), and intracranial hemorrhage (1.9 +/- 0.3 pg/ml) compared with control patients (1.2 +/- 0.1 pg/ml). A significant relationship was found between intracranial pressure and the cerebrospinal fluid vasopressin concentration within all groups of patients and in the whole sample as well (r = 0.79; p less than 0.001). In the groups of patients with intracranial tumor, hydrocephalus, and intracranial hemorrhage, some individuals showed plasma vasopressin concentrations inappropriate to the corresponding plasma osmolality, but no relationship was found between intracranial pressure and plasma vasopressin concentration. It is suggested that increased intracranial pressure is a stimulus to centrally released vasopressin. The clinical importance of increased cerebrospinal fluid vasopressin concentrations is still not known.

Adolescent↗
PubMed1984

Effects of long-term carbamazepine treatment on water metabolism and plasma vasopressin concentration.

Plasma osmolality, sodium and vasopressin were measured in 7 patients before and during long-term treatment with carbamazepine, under resting conditions, and following an oral water load of 20 ml/kg body weight. During carbamazepine treatment, the ability to excrete the oral water load was decreased, the urine/plasma osmolality ratio was higher, and the free water clearance was lower. In two patients, the ability to excrete the oral water load was severely impaired, and the free water clearance remained negative following water loading. Plasma osmolality and sodium concentration were significantly lower during carbamazepine administration, but despite this the plasma vasopressin concentration remained unchanged or was even slightly increased. Four patients showed inappropriately high vasopressin concentrations in relation to the corresponding plasma osmolality when taking carbamazepine. The findings suggest a decrease in plasma osmolality during carbamazepine treatment, which might account for the inappropriate secretion of vasopressin. The latter might cause clinical symptoms of water intoxication, as has previously been reported in a few patients on carbamazepine therapy.

Adult↗
PubMed1984

Plasma vasopressin, cortisol, and growth hormone concentrations in relation to surgery in the suprasellar region.

Posterior and anterior pituitary functions were assessed in 8 patients before, during, and after surgery for tumors in the suprasellar region. Preoperatively, all patients but one responded adequately to an osmotic stimulus with a rise in plasma vasopressin (AVP) and all but one showed adequate cortisol response to adrenocorticotropic hormone (ACTH) and hypoglycemia. During surgery a transient rise was seen in plasma levels of AVP (5 out of 8 patients), cortisol (7 out of 8 patients) and growth hormone (4 out of 8 patients). This response could be predicted from the preoperative stimulation tests. Postoperatively the AVP response to osmotic stimuli was impaired in 4 out of 5 patients, although urine volume had returned to normal after a transient polyuric phase. The response of plasma cortisol to ACTH was still adequate but lower than preoperatively.

Adenoma↗
PubMed1984

Hepatitis B virus DNA (HBV-DNA) in anti-HBe positive sera.

HBV-DNA measured by the spot hybridization technique, was found in the sera of 28 of 106 (26.4%) anti-HBe positive carriers of HBsAg. Dane particle-associated HBeAg, HBcAg and HBV-specific DNA-polymerase activity were found in the sera of nine (8.5%), five (4.7%) and two (1.9%) of these patients, respectively. All carriers with serum HBV-DNA had chronic liver disease and 18 had intrahepatic delta-Ag and serum anti-delta at titers higher than 1/5000. Intrahepatic HBcAg was detected in the nuclei of 90% of delta negative individuals; 50% of them also had cytoplasmic fluorescence. Only two of the 18 patients with intrahepatic delta-Ag (11%) had HBcAg in the liver. Viral nucleic acid was not found in the sera of 15 other patients with chronic hepatitis, seven of whom had intrahepatic delta-Ag. Serum HBV-DNA was also negative in the remaining 63 symptomless carriers of HBsAg lacking markers of delta infection. Interestingly, although DNA-polymerase negative, some sera gave autoradiographic spots of high optical density. HBV-DNA was detected in them at concentrations typical of sera which are usually both DNA-polymerase and HBeAg positive. Detection of HBV-DNA in serum represents the most direct and sensitive in vitro assay for assessing HBV infectivity and characterizes HBsAg carriers with HBV-related liver damage and ongoing HBV replication independently from the state of HBeAg/anti-HBe system. In the Mediterranean area, the majority of anti-HBe positive carriers with serum HBV-DNA have chronic liver disease and delta infection.

Carrier State↗
PubMed1983

Unrelatedness of factor VIII-derived non-A/non-B hepatitis and hepatitis B virus.

A DNA hybridization assay was used to detect hepatitis B virus (HBV)-specific DNA sequences in extracted sera obtained from chimpanzees infected with HBV, hepatitis A virus (HAV), and a factor VIII-derived non-A/non-B (NANB) agent. The results did not reveal any HBV-DNA homology with sera obtained from animals infected with HAV or factor VIII-derived NANB. Sera obtained from two HBV-infected chimpanzees demonstrated that HBV-specific DNA could be detected during the acute phase of the disease. In addition, an HBV-specific DNA-dependent DNA polymerase assay did not demonstrate any statistically significant activity in 12 of 12 NANB acute-phase specimens or in 6 of 6 NANB chronic-phase specimens. These results suggest that the factor VIII-derived NANB agent is unrelated to HBV.

Animals↗
PubMed1983

'Core' and 'extended' social networks in relation to health and illness.

This paper considers several models of the nature of the association that has been found between characteristics of social networks and health. Such an association does not appear to be adequately accounted for by a deleterious effect of illness on social contact, nor by the role of social networks in mediating health-related practices or in buffering the effects of stress. Thus the proposition is tentatively warranted that the social network is more directly and causally involved in health outcomes--perhaps through the impact of social feedback as mediated by the network. It is argued that the social processes that affect the association between networks and health involve a larger social unit than the small core networks that have generally been the focus of study. Assuming that the individual's susceptibility to illness is affected by the adequacy of the core network, we must deal with the fact that the vulnerability of the core network to loss without adequate replacement is, in turn, affected by the structure of the larger, extended network in which the core network is embedded. By shifting attention to these extended networks, it should also become possible to integrate findings from network studies with more traditional epidemiological findings relating such macro-variables as social class to illness.

Adult↗