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Biomedical subjects

J Giese

Publications and source records attributed to J Giese.

At least 19 recordsLinked to original sources
PubMed2001

Multimodal assessment of dissociation in adolescents: inpatients and juvenile sex offenders.

Two samples of adolescents were studied to assess the validity of several measures of dissociation. The first sample included 70 males from a residential treatment program for adolescent sex offenders (ASO). The second were 47 psychiatric inpatients. The measures included the DSM-IV field trial questionnaire for Dissociative Disorders of Childhood, Child Dissociative Checklist, Adolescent-Dissociative Experiences Schedule, Trauma Symptom Checklist for Children, and the Dissociation Research scale. Ten of the 70 adolescent sex offender subjects (14.3%) were identified as meeting DSM-IV criteria for a Dissociation-spectrum disorder diagnosis and two (4.2%) of the psychiatric patients. Between-groups analyses with the ASO revealed significant differences on the Child Dissociative Checklist and the Dissociation Research Scale. Cumulative trauma did not differ significantly between the dissociative and nondissociative groups of ASO, but physical abuse was related to a diagnosis of dissociation in this sample. The dissociation measures were highly intercorrelated for both groups, and suggest that they measure a similar construct.

Adolescent↗
PubMed1998

Divergent cardiac response to exercise in essential hypertension vs. normotension and the effect of enalapril.

The aims of this study were to examine (1) the cardiac response to exercise in essential hypertension and (2) the effect of long-term enalapril treatment on cardiac reserve. Ten normotensive control subjects and 15 patients with moderate, essential hypertension underwent radionuclide ventriculography during graded, supine exercise (0 W-50 W-100 W). The hypertensive patients were studied during monotherapy using hydrochlorothiazide and 3 and 12 months after supplementation with enalapril 10-40 mg o.d. During exercise, the control subjects demonstrated a 17% increase in left ventricular ejection fraction (LVEF) mediated by a 30% decrease in end-systolic volume, a small increase in stroke volume and a minor biphasic (increase-decrease) change in end-diastolic volume. In the hypertensive patients, both the end-diastolic and the end-systolic volume increased substantially with no increase in LVEF, although stroke volume increased by 33%. Long-term therapy with enalapril induced only a minor change towards a more normal pattern of cardiac response to exercise. The hypertensive patients increased their stroke volume during exercise by recruiting preload reserve instead of increasing contractility. Long-term treatment with enalapril had little, if any, effect on this abnormal cardiac response.

Adult↗
PubMed1993

[NO-NO-NO].

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Humans↗
PubMed1993

Nature of elevated blood pressure in normoalbuminuric type I diabetic patients. Essential hypertension?

This study was undertaken to characterize type I diabetic patients with essential hypertension with respect to kidney function, renal hormones, and endothelial function. After 4 weeks without antihypertensive treatment, a cross-sectional study was carried out in the following groups: group 1, 14 healthy controls; group 2, 13 nondiabetic patients with essential hypertension (blood pressure > or = 140/90 mm Hg); group 3, 11 type I diabetic patients with hypertension but urinary albumin excretion (UAE) persistently normal (UAE: 10 mg/24 h, range 3 to 18) both before, during, and after discontinuing antihypertensive treatment; group 4, 15 type I diabetic patients with clinical nephropathy (UAE: 611 mg/24 h, range 192 to 3837) and hypertension. Systolic and diastolic blood pressures were similar in the three hypertensive groups: 147/96 +/- 8/6, 150/94 +/- 11/9, and 152/92 +/- 12/6 mm Hg (groups 2, 3, and 4, respectively) but elevated compared with controls (114/74 +/- 9/9 mm Hg, P < .001). The diabetic patients with essential hypertension were hyperfiltering in contrast to patients with nephropathy (glomerular filtration rate 114 +/- 23 v 90 +/- 21 mL/min/173 m2, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Atrial natriuretic peptide (ANP) decrease during normal pregnancy as related to hemodynamic changes and volume regulation.

BACKGROUND: Volume regulation and hemodynamic functions change during pregnancy, leading to marked increases in blood volume and cardiac output, peripheral vasodilatation and reduced sensitivity to angiotensin. Atrial natriuretic peptide (ANP) is intimately involved in fluid and sodium homeostasis and exerts marked relaxant activity on vascular smooth muscle pre-contracted with angiotensin. This study was performed to clarify the role of ANP as a regulator of maternal physiology. METHODS: 40 normal primigravidae were examined five times during pregnancy plus 12 weeks after delivery. Each time were measured: ANP, aldosterone, renin, blood volume (carbon monoxide), cardiac output (Doppler), blood pressure and sodium excretion. Interdependence of the changes in ANP and in the other parameters was tested using Spearman's rank correlation test on the delta (delta)-values (the differences between investigations). RESULTS: P-ANP in the 20th week was 11.4 (8.5-18.9) pmol.l-1 (median, 25 and 75 percentiles), the same as 12 weeks after delivery, 11.5 (9.6-15.2) pmol.l-1, and in a non-pregnant control group, 10.4 (9.0-12.5) pmol.l-1 (n = 20). All measurements of P-ANP during the 3rd trimester were lower than in the 20th week and 12 weeks after delivery, p < 0.0001 (Wilcoxon matched-pairs test). There was a negative correlation between changes in P-ANP and changes in: a) blood volume. R = 0.69, p < 0.0001, b) aldosterone, R = 0.58, p < 0.0001, c) renin, R = -0.54, p < 0.001, d) cardiac output, R = 0.61, p < 0.001. There was a positive correlation between changes in P-ANP and changes in: a) fractional excretion of sodium, R = 0.54, p < 0.0001, and b) total peripheral resistance. R = 0.52, p < 0.0001. CONCLUSION: Decrease in p-ANP is one of the mechanisms whereby blood volume is increased and maintained during pregnancy. The competitive relationship between ANP and the renin aldosterone system in regulating sodium balance and fluid volume is preserved during pregnancy. The results substantiate the physiological importance of ANP as a regulator of blood volume. ANP does not function as a vasodilator during pregnancy.

Adolescent↗
PubMed1993

Distribution of onchocerciasis in selected river basins of four west African countries.

Detailed epidemiological mapping of eight river basins was conducted in four West African countries as part of an effort to identify the communities at risk of onchocercal blindness to guide a programme of large scale ivermectin distribution, attempting control of eye disease. The results show a surprising variability of pattern in the geographical distribution of intensity of onchocerciasis infections in the communities of the river basins investigated. These patterns were at time very different from what was expected on the basis of the available entomological and demographic information. The technique of detailed mapping proved very useful in achieving an excellent coverage of the communities at risk of onchocercal blindness where, so far, satisfactory treatment coverage has been attained for four consecutive yearly treatments.

Animals↗
PubMed1993

N-acetylcysteine inhibits angiotensin converting enzyme in vivo.

Nitrate tolerance has been explained by 1) a direct loss of pharmacological effect due to reduced bioconversion and 2) an indirect effect due to activation of the renin/angiotensin system and counter-regulatory vasoconstriction. The sulfhydryl compound N-acetylcysteine (NAC) has been shown to attenuate and partly counteract tolerance to nitrates, and this effect has been attributed to a nitrate/sulfhydryl interaction and increased production of vasoactive intermediates. The effect of NAC on counter-regulatory mechanisms is, however, unknown. This study examined whether NAC modulates the function of the renin/angiotensin system in normal rats and in nitrate-tolerant healthy volunteers. Animal study: Conscious rats received NAC (5 mmol/kg/hr i.v., n = 8) or placebo (N-acetylserine, n = 8). Two hours of NAC infusion significantly reduced the pressor effect of angiotensin I (ANG I) by 39 +/- 14% (mean +/- SEM) and reduced angiotensin converting enzyme activity by 31% in plasma (N-acetylserine: 74 +/- 9 nmol/min/mg, NAC: 51 +/- 7) and 43% in kidney (N-acetylserine: 0.9 +/- 0.3, NAC: 0.5 +/- 0.1 nmol/min/mg protein) (P < .05). Clinical study: Isosorbide dinitrate (5 mg/hr) was infused into six male volunteers for 48 hr. NAC (2 g i.v. followed by 5 mg/kg/hr) was co-infused from 24 to 48 hr. Plasma angiotensin II (ANG II) increased during the first 24 hr of isosorbide dinitrate infusion and decreased from 28 +/- 4 to 14 +/- 2 ng/l after 2 hr of NAC infusion (P < .05). The results suggest that sulfhydryl supplementation modifies the function of the renin/angiotensin system in vivo, an effect probably mediated by inhibition of angiotensin converting enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1992

Renal sites of action of physiological increases in plasma atrial natriuretic factor concentration in essential hypertension.

OBJECTIVES: To investigate the renal, haemodynamic and neurohormonal responses to low-dose infusions of atrial natriuretic factor (ANF) in hypertensive humans. DESIGN: Ten patients with mild-to-moderate essential hypertension received incremental infusions of 3 and 6 ng/kg per min ANF or vehicle alone whilst on a constant dietary sodium intake. A 90-min basal clearance period was followed by two 2-h infusion periods, with urine collection in the last 90 min of each period. In each of the three clearance periods, glomerular filtration rate (GFR), renal tubular function, and the activity of the renin-angiotensin and sympathetic nervous systems were determined. METHODS: The renal sites of ANF action were established by simultaneous measurements of 51Cr-ethylenediaminetetraacetate lithium and sodium clearances. Plasma concentrations of neurohormones were measured by radioimmunoassays. RESULTS: Plasma ANF concentrations increased by 1.6- and 2.5-fold during the lower and higher ANF infusion rates, respectively. Plasma cyclic guanosine monophosphate concentrations increased in parallel. ANF caused no changes in supine systolic and diastolic blood pressure or in heart rate. In contrast, haematocrit values increased progressively across the study. The renal effects of ANF administration were characterized by an unaltered GFR and significant increases in the renal clearances of lithium (a marker of end-proximal fluid delivery) and sodium when compared with vehicle infusions, whereas urine flow did not change. Estimated values of fractional proximal and distal tubular sodium reabsorption decreased significantly. Plasma concentration of active renin decreased during ANF infusions, but no significant changes in plasma levels of renin substrate, angiotensin I, angiotensin II or aldosterone were observed. A subtle activation of the sympathetic nervous system was indicated by a moderate increase in plasma noradrenaline during the ANF infusions. CONCLUSIONS: These results indicate that even small increases in plasma ANF, as can be found during physiological conditions, induce natriuresis in patients with essential hypertension by enhancing fluid delivery from the proximal tubules, in addition to impairing distal fractional sodium reabsorption. With minor exceptions, the ANF infusions caused qualitatively and quantitatively similar renal, haemodynamic and endocrine effects in the hypertensive patients as in a previously studied group of normotensive subjects.

Adult↗
PubMed1992

Radioimmunoassay of endothelin in human plasma.

A specific and sensitive radioimmunoassay (RIA) for determination of endothelin-1 (ET-1) in human plasma has been developed. Antibodies were raised in rabbits using synthetic ET-1 conjugated to thyroglobulin as immunogen. The antibodies obtained were used at a final dilution of 1:300,000 yielding maximum binding of 61.7 +/- 3.0% (mean +/- 1 SD, n = 20) of 125I-ET-1. The ID50 (inhibitory dose 50%) was 4.5 +/- 0.6 fmol/100 microliters (mean +/- 1 SD, n = 20). The sensitivity of the RIA was 0.33 fmol/100 microliters standard solution. No cross reactivity was observed with endothelin-3, big-endothelin-1, atrial natriuretic factor, angiotensin I or angiotensin II. The cross-reactivity with endothelin-2 was 100%. Endothelin was extracted from acidified plasma with Sep-pak C18 cartridges and recovery of ET-1 added to normal plasma was 70.9 +/- 10.3% (mean +/- 1 SD, n = 12). The concentration of ET-1 in plasma from normal subjects was 1.5 +/- 0.4 pmol/l (mean +/- 1 SD, n = 11) ranging from 1.0 to 2.2 pmol/1. Extracts of normal human plasma subjected to high performance liquid chromatography on a reverse phase C18 column showed one peak of immunoreactivity co-eluting with the standard for ET-1. From these data it is concluded that the immunoreactive material measured in normal plasma with the present RIA is identical to ET-1.

Animals↗
PubMed1991

Efficacy of captopril in postponing nephropathy in normotensive insulin dependent diabetic patients with microalbuminuria.

OBJECTIVE: To assess the effectiveness of angiotensin converting enzyme inhibition in preventing the development of diabetic nephropathy (albuminuria greater than 300 mg/24h). DESIGN: Open randomised controlled study of four years' duration. SETTING: Outpatient diabetic clinic in tertiary referral centre. PATIENTS: 44 normotensive (mean blood pressure 127/78 (SD 12/10) mm Hg) insulin dependent diabetic patients with persistent microalbuminuria (30-300 mg/24h). INTERVENTIONS: The treatment group (n = 21) was initially given captopril (25 mg/24 h). The dose was increased to 100 mg/24 h during the first 16 months and thiazide was added after 30 months. The remaining 23 patients were left untreated. MAIN OUTCOME MEASURES: Albuminuria, kidney function, development of diabetic nephropathy (albuminuria greater than 300 mg/24 h), and arterial blood pressure. RESULTS: Clinical and laboratory variables were comparable at baseline. Urinary excretion of albumin was gradually reduced from 82 (66-106) to 57 (39-85) mg/24 h (geometric mean (95% confidence interval)) in the captopril treated group, whereas an increase from 105(77-153) to 166 (83-323) mg/24 h occurred in the control group (p less than 0.05). Seven of the untreated patients progressed to diabetic nephropathy, whereas none of the captopril treated patients developed clinical overt diabetic nephropathy (p less than 0.05). Systemic blood pressure, glomerular filtration rate, haemoglobin A1c concentration, and urinary excretion of sodium and urea remained practically unchanged in the two groups. CONCLUSIONS: The findings suggest that angiotensin converting enzyme inhibition postpones the development of clinical overt diabetic nephropathy in normotensive insulin dependent diabetic patients with persistent microalbuminuria.

Adolescent↗
PubMed1991

Detailed epidemiological mapping of three onchocerciasis foci in West Africa.

Detailed epidemiological mapping of three isolated foci of hyperendemic blinding onchocerciasis was undertaken in three West African countries as part of community trials of ivermectin, a new microfilaricide for the treatment of human onchocerciasis. The results show that the geographical distribution of the prevalence and intensity of onchocerciasis infection in the community can be very different from what was expected on the basis of demographic and entomological information. The technique of detailed epidemiological mapping is an important tool for the identification of target populations for large scale ivermectin treatment of onchocerciasis. It is being used extensively in the Onchocerciasis Control Programme in West Africa.

Africa, Western↗
PubMed1991

Effects of insulin on renal haemodynamics and sodium handling in normal subjects.

Diabetic patients treated with insulin injected subcutaneously are characterized by peripheral hyperinsulinaemia and an increased mass of total body exchangeable sodium. We hypothesized that this may cause, at least in part, the glomerular hyperfiltration seen in the diabetic state. Six normal subjects were studied on 2 days in random order. Day A: Basal state for 40 min, hyperinsulinaemic euglycaemic clamp for 1 h (insulin infusion rate 2 mU kg-1 min-1 and 50% glucose infusion) and hyperinsulinaemic euglycaemic clamp combined with volume expansion (2 1 isotonic sodium chloride) for 2 h. Day B: as day A, but without insulin and glucose infusion. During combined volume expansion and hyperinsulinaemia an increase in glomerular filtration rate (GFR) (128 +/- 6 vs 117 +/- 8 ml min-1 1.73 m-2, p less than 0.01) and lithium clearance (CLi) (50 +/- 4 vs 33 +/- 5 ml min-1 1.73 m-2, p less than 0.01) was observed compared with basal conditions. GFR and CLi were unchanged during day B. Insulin infusion reduced renal sodium excretion. Absolute proximal tubular reabsorption was unchanged on both days. Insulin infusion without volume expansion caused a decrease of 24% in the fractional distal sodium excretion. Superimposed volume expansion and the concomitant increase in GFR and CLi was accompanied by a subsequent enhanced fractional distal sodium excretion of 27%. The changes in plasma concentrations of aldosterone, renin, angiotensin II, atrial natriuretic peptide and catecholamines did not explain the differences in GFR. An increase in GFR of 10%, comparable with that observed in diabetic patients, was induced by combined hyperinsulinaemia and volume expansion in euglycaemic normal subjects. The enhanced GFR is probably a compensatory response to the sodium retention induced by the action of insulin on the distal tubules.

Adult↗
PubMed1991

Unchanged extraction of atrial natriuretic factor across the chronic ischemic human kidney.

The extractions of atrial natriuretic factor (EANF) and the glomerular filtration marker 51Cr-ethylenediamine tetraacetic acid (EEDTA) were determined before and after intravenous injection of furosemide across each of the two kidneys during renal vein catheterization in hypertensive patients with unilateral or bilateral renovascular disease. Before administration of furosemide, EANF was approximately 55% across both the more and the less affected kidney while EEDTA was significantly decreased across the more affected kidney. Significant lateralization of renin secretion to the more affected kidney was found, demonstrating an enhanced ipsilateral formation of renin. Administration of furosemide caused a significant decrease in EEDTA across the less affected kidney while the ipsilateral EANF did not change. Furosemide caused no change in EEDTA or EANF across the more affected kidney. No significant correlations were found between EANF and EEDTA. These results demonstrate that the extraction of ANF is unchanged across the chronic ischemic human kidney. Furthermore, in the single kidney, changes in EEDTA, as induced by furosemide, are not related to changes in ipsilateral EANF. Since the relation between simultaneously determined single kidney extractions of ANF and 51Cr-EDTA reflects the relation between the single kidney clearance of ANF and the ipsilateral glomerular filtration rate, our data indicate a dissociation between changes in the single kidney glomerular filtration rate and the ipsilateral total renal clearance of ANF.

Atrial Natriuretic Factor↗
PubMed1991

Renal and endocrine effects of physiological variations of atrial natriuretic factor in normal humans.

The renal and endocrine effects of incremental infusions of 3 and 6 ng.kg-1.min-1 of exogenous atrial natriuretic factor (ANF)-(99-126) or placebo were investigated in 10 normal subjects. A 90-min basal period was followed by two 2-h infusion periods with urine collection in the last 90 min of each period. Plasma ANF concentration increased by 50 and 150%, respectively, from a basal value of 6.2 +/- 3.1 pmol/l. Plasma guanosine 3',5'-cyclic monophosphate concentration increased in parallel with ANF. Blood pressure and heart rate were unchanged, whereas hematocrit was stepwise increased. 51Cr-EDTA clearance (GFR) did not change, but ANF caused an increase in Li clearance (a measure of end-proximal fluid delivery), Na clearance, and urine flow compared with time-matched control values. These excretory effects of ANF were mainly due to prevention of the 20- to 50% decreases occurring in the placebo series. Calculated values of fractional proximal and distal tubular Na reabsorption decreased significantly. ANF caused a decrease in plasma concentrations of active renin and aldosterone, whereas renin substrate, angiotensin I, and angiotensin II concentrations were unaltered. A subtle increase in plasma concentrations of norepinephrine and epinephrine was observed during the ANF infusions. These data suggest that the natriuretic effect of ANF is caused by an increased fluid delivery from the proximal tubule in addition to a fall in fractional distal Na reabsorption.

Adult↗
PubMed1991

Comparison of different standards used in radioimmunoassay for atrial natriuretic factor (ANF).

Six different standards for determination of atrial natriuretic factor (ANF) in human plasma samples have been compared using our radio-immunoassay for ANF: International standard 85/669, National Biological Standard Boards, UK; Bachem standard, Torrance, USA; Bachem standard, Bubendorf, Switzerland; Bissendorf standard, Wedemark, Germany; Peninsula standard, Belmont, USA; UCB-Bioproducts standard, Brussels, Belgium. Standard curves obtained with different preparations were in parallel but showed considerable quantitative differences. Standard curves referring to the Bissendorf standard and the International standard, respectively, were almost identical. The dose required for 50% of binding inhibition (ID50s) determined with the Peninsula, UCB and Swiss Bachem standards were higher and ID50 for the American Bachem standard was much lower than ID50 for the International standard. In consequence, estimates of the ANF content in human plasma samples with different standard preparations as the reference showed a considerable variability. With the international standard as the gold reference (plasma ANF concentration 100%) the apparent plasma ANF concentrations measured with the other reference preparations varied from 42% to 178%.

Atrial Natriuretic Factor↗
PubMed1991

Effects of hyperglycaemia on kidney function, atrial natriuretic factor and plasma renin in patients with insulin-dependent diabetes mellitus.

In normoalbuminuric patients with insulin-dependent diabetes mellitus, plasma atrial natriuretic factor (ANF), cyclic GMP and active renin and the renal clearances of [99Tcm]-diethylenetriaminepentaacetic acid (DTPA) lithium and sodium were studied on a hyperglycaemia day and a euglycaemia day. Baseline euglycaemia was achieved by an overnight variable insulin infusion, which during study days was fixed at the rate necessary to maintain euglycaemia in the morning. After a baseline euglycaemic clearance period of 90 min, measurements were repeated in a new 90-min period beginning 150 min later. On the hyperglycaemia day i.v. infusion of 20% glucose was started at the end of the euglycaemic baseline period, increasing blood glucose (5.3 +/- 1.3 vs 12.1 +/- 1.2 mmol l-1, p less than 0.01). On the euglycaemia day blood glucose declined (5.1 +/- 1.0 vs 4.2 +/- 1.0 mmol l-1, p less than 0.02). Glomerular filtration rate (GFR) was unchanged by acute hyperglycaemia (127 +/- 16 vs 129 +/- 24 ml min-1, NS), but nearly normalized during maintained euglycaemia on the euglycaemia day (124 +/- 17 vs 105 +/- 16 ml min-1, p less than 0.01). When comparing the hyperglycaemic study period with the similarly timed period on the euglycaemia day, GFR was elevated by hyperglycaemia (129 +/- 24 vs 105 +/- 16 ml min-1, p less than 0.01), while the renal clearances of lithium and sodium were similar. Consequently, the calculated absolute proximal reabsorption rate of sodium and water was elevated during hyperglycaemia. Hyperglycaemia reduced the slight decline in plasma concentrations of ANF and cyclic GMP observed on the euglycaemia day. Active renin, glucagon and plasma osmolality were unchanged. In conclusion, marked changes in glomerular filtration rate are induced by changes in blood glucose concentration, but the effect is delayed and thus not directly related to renal tubular transport of glucose. Hyperglycaemia does not affect renal clearances of lithium and sodium, while proximal tubular reabsorption is markedly stimulated. These changes are not related to changes in ANF, renin, glucagon or plasma osmolality.

Adult↗
PubMed1991

Onchocerciasis distribution and severity in five West African countries.

The Onchocerciasis Control Programme in West Africa recently extended its operation to Guinea, Guinea-Bissau, the western part of Mali, Senegal and Sierra Leone. To estimate the number of people infected and blinded by the disease and to determine its distribution and severity in the extension area, 215 villages were selected, using a stratified random sampling procedure, and surveyed. All the relevant entomological information available at the time was used in the sampling procedure and in the selection of 92 non-representative villages that were surveyed to confirm the findings. In addition, the populations of 608 villages were examined to map out in detail the distribution of onchocerciasis in the areas at a high risk of onchocercal blindness. The study estimated that 1,475,367 people were infected and 23,728 were blinded from onchocerciasis out of a rural population of 4,464,183. The northern and western part of the study area and the lower Niger basin presented a low or no risk of onchocercal blindness. The upper Niger basin, the south-central part of Sierra Leone, and three small foci in the Gambia, Bakoye, and lower Niger river basins were areas with a high risk of onchocercal blindness. The other parts of the study area presented a medium risk of onchocercal blindness. By detecting the communities at risk of onchocercal disease this study permits the selection of populations for disease control based on mass distribution of ivermectin, a microfilaricide.

Gambia↗