Biomedical subjects

P Blockx

Publications and source records attributed to P Blockx.

At least 37 records · Page 2Linked to original sources

PubMed1994

Comparison of the effect of conventional highly selective vagotomy and anterior gastric wall stapling with posterior truncal vagotomy on the gastric emptying rate for solid meals in beagle dogs.

Anterior gastric wall stapling combined with posterior truncal vagotomy has been used as a new and adequate gastric acid output-reducing procedure. Severing the posterior vagal trunk as well as stapling the anterior gastric wall could impair gastric emptying. In this study, the gastric emptying rate for solid food, using a radionuclide technique, has been evaluated in 2 series of canine experiments. Compared to the results after conventional highly selective vagotomy, a temporary delay in the gastric emptying rate could be found after this new procedure, however, completely normalizing 1 year later.

Animals↗

PubMed1993

Hyperfunctioning unilateral adrenal macronodule in three patients with Cushing's disease: hormonal and imaging characterization.

We aimed to investigate the dynamics of adrenocorticotropin (ACTH) and cortisol secretion in pituitary-dependent Cushing's syndrome with bilateral macronodular adrenal hyperplasia presenting as a single adrenal macronodule, and to determine the imaging characteristics of this syndrome. Three female patients were studied. Plasma ACTH and serum cortisol secretion were studied by determining their rhythmicity and pulsatility and their responses to the administration of ovine corticotropin-releasing factor, thyrotropin-releasing hormone, metyrapone, tetracosactrin, insulin and dexamethasone. Techniques used to localize the anatomical lesion were bilateral simultaneous inferior petrosal sinus sampling, magnetic resonance examination of the pituitary, computed tomography (CT) scanning and [75Se]cholesterol scintigraphy of the adrenal glands. Plasma ACTH and serum cortisol levels were measured using a commercial radioimmunoassay and an immunoradiometric assay. The ACTH and cortisol pulse number and amplitude were calculated using established computer software. In all three patients ACTH and cortisol secretory dynamics fulfilled the requirements for diagnosis of pituitary-dependent Cushing's syndrome. A close relationship between ACTH and cortisol pulses also favored a pituitary dependency. Study of the amplitude of cortisol pulses classified two patients in the group of hypopulsatile Cushing's disease. Adrenal CT scanning demonstrated the presence of a large single nodule. [75Se]Cholesterol scintigraphy showed bilateral radionuclide uptake, although mostly localized over the adrenal nodule. All patients underwent successful trans-sphenoidal hypophysectomy. Over a period of 1 year, a slow shrinkage of the adrenal nodule was observed in two patients, while no change in volume was observed in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗

PubMed1992

Adrenocorticotropin hormone, beta-endorphin and cortisol responses to oCRF in melancholic patients.

Several authors have reported attenuated adrenocorticotropin hormone (ACTH) responses to corticotropin releasing factor (CRF) administration in melancholic patients as compared with healthy controls. In order to explore the integrity of the hypothalamic-pituitary-adrenal (HPA)-axis in melancholics, we examined the following parameters in 98 subjects: the ACTH; beta-endorphin; and cortisol responses to ovine CRF (oCRF) (100 micrograms/i.v.); and the postdexamethasone cortisol values. We found significant lower CRF-induced ACTH responses in melancholic patients as opposed to healthy controls and minor depressives, while major depressives occupied an intermediate position. The psychopathological correlates of the blunted CRF-induced ACTH responses were feelings of worthlessness, self-reproach, or excessive guilt. The CRF-stimulated beta-endorphin and cortisol response did not differ between the study samples. Higher baseline plasma cortisol was associated with attenuated CRF-induced ACTH responses, but these effects were not pertinent to melancholia. There were no relationships between the disordered oCRF test results, and postdexamethasone cortisol values, age, body size, sex and severity of illness. The diagnostic power of the oCRF and the dexamethasone suppression test for melancholia is enhanced when both test results are combined.

Adrenocorticotropic Hormone↗

PubMed1992

TSH responses to TRH as a function of basal serum TSH: relevance for unipolar depression in females--a multivariate study.

Baseline thyroid-secreting-hormone (TSH)-assessed by means of ultrasensitive assays (IRMA)-and free-thyroid-hormone (FT4) levels were determined in 84 depressed females, and the TSH responses to 200 micrograms thyrotropin-releasing hormone (TRH) (IV) measured. It was found that TRH-induced TSH responses were linearly and positively related to basal TSH-IRMA; lower TRH-stimulated TSH secretion in melancholic patients was attributable to lowered basal TSH-IRMA values. A progression was found-within the euthyroid range-of basal TSH-IRMA values towards lower levels along the diagnostic spectrum: the highest basal TSH-IRMA levels were witnessed in minor depressives and the lowest in melancholics, while simple major-depressed females occupied an intermediate position. This shift appears to be indicative of severity of illness. Basal TSH-IRMA data can roughly be used as a clinical tool separating melancholia from minor depression: at a threshold value of less than or equal to 1 microUI/ml, sensitivity was 56% and specificity 92%. It is concluded that basal TSH-IRMA provides a more accurate representation of melancholia than peak TSH responses, which appear to constitute little more than a magnified, but biased signal of basal TSH-IRMA. In future, the assay of basal TSH-IRMA could replace TRH testing.

Aging↗

PubMed1991

Serum postdexamethasone prolactin measures in depressive patients and control subjects.

Recently, some researchers noted significant positive relationships between postdexamethasone serum cortisol and prolactin levels, whilst endogenous depressives exhibited a significantly lower suppression of prolactin by dexamethasone than non-endogenous patients or normal controls. To ascertain the extent of prolactin responses to dexamethasone in severely depressed patients, we measured 8 a.m. pre- and postdexamethasone prolactin levels in 104 depressed and 42 normal subjects. Serum cortisol levels were also determined in depressed patients before and after dexamethasone administration. We found a significant suppressive effect of dexamethasone on prolactin levels. There were no significant differences either in pre- or postdexamethasone prolactin, or in actual dexamethasone-induced decrements in prolactin between normal controls, melancholics, simple major or minor depressed subjects. We have not found any significant relationships between cortisol and prolactin, either under baseline or postdexamethasone conditions.

Adjustment Disorders↗

PubMed1991

The use of 99Tcm-HSA dynamic vascular examination in the staging and therapy monitoring of reflex sympathetic dystrophy.

Evaluation of the local haemodynamic changes was performed in 93 patients with untreated reflex sympathetic dystrophy, based upon a simple dynamic vascular examination technique, using 99Tcm-HSA. According to the disease stage, opposite observations were made: in stage I (n = 72) an increase in both blood flow and blood volume was found, in stage II (n = 21) in contrast, both blood flow and blood volume decreased. These findings show that reflex sympathetic dystrophy can be staged according to haemodynamic changes. It is obvious, moreover, that a careful haemodynamic staging is most important for the choice of the right vasoactive treatment; e.g. calcitonin (vasoconstrictive) versus guanethidine (vasodilating).

Calcitonin↗

PubMed1991

L-5-hydroxytryptophan stimulated cortisol escape from dexamethasone suppression in melancholic patients.

The dexamethasone suppression test (DST) was carried out in 62 depressed patients. At 0800 the postdexamethasone cortisol values were determined and 125 mg L-5-hydroxytryptophan (L-5-HTP) was administered. The second cortisol sample at 0930 revealed a significant enhancing effect for L-5-HTP on the postdexamethasone cortisol values in melancholic patients, whereas no effects were detected in minor depressives. Our results show that L-5-HTP converts some DST suppressors into nonsuppressors, whereas the escape from dexamethasone in some nonsuppressors is markedly stimulated. The L-5-HTP-stimulated 0930 postdexamethasone cortisol values performed markedly better than the 0800 DST results: at a cut-off value of greater than or equal to 5 micrograms/dl the sensitivity for melancholia increased from 46% to 68%, and the specificity remained unchanged (96%).

5-Hydroxytryptophan↗

PubMed1991

Changes in serum thyroid hormone autoantibody concentrations during pregnancy: a case report.

A 29-year-old female patient with Graves' disease who developed thyroid hormone autoantibodies (THAA) under treatment with methimazole is presented. THAA were identified as IgG-kappa. During a first pregnancy that ended by miscarriage in the 3rd month, the titer of anti-thyroxine autoantibodies decreased by about 30%. Relapse of Graves' disease occurred 2 months later and an increase in serum THAA concentration to the initial titer was observed. THAA titer remained unchanged during treatment with methimazole and afterwards during thyroxine supplementation for radioiodine-induced hypothyroidism. During a second pregnancy, a decrease in anti-thyroxine autoantibody titer reached 45% at the time of delivery and an increase by 20% was noted 5 months later. A similar decline in THAA concentration was shown during a third pregnancy. The changes in THAA concentrations observed during pregnancy suggest an immunological influence of pregnancy on the THAA production, as previously demonstrated in other autoimmune diseases, like Hashimoto's thyroiditis.

Adult↗

PubMed1991

Calculation of half-life of carcinoembryonic antigen after lung tumour resection: a case report.

Since little is known about carcinoembryonic antigen (CEA) half-life in humans, we followed changes in CEA levels after curative resection of a small bronchial adenocarcinoma in a 54 yr old man with an unusually high preoperative serum CEA level of 1,199 ng.ml-1. Serum CEA followed a four phase curve with an initial increase, attributed to release of CEA from the tumour, a rapid fall during four days (CEA half-life 3.2 days), a slower exponential decay to normal levels during almost three months (CEA half-life 11 days) and eventually maintenance of normal levels for 14 months. These results are consistent with data from animal experiments and a single report on CEA half-life in humans, but CEA half-life seems longer in man than in animals. This observation also suggests that a very high serum CEA level should not in itself preclude curative surgical resection of a primary bronchogenic carcinoma.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed1990

The relationships between the cortisol responses to dexamethasone and to L-5-HTP, and the availability of L-tryptophan in depressed females.

In order to investigate the relationships between the hypothalamic-pituitary-adrenal (HPA)-axis activity, the central serotonergic neurotransmission, and the peripheral metabolism of l-tryptophan (L-TRP), the authors measured the following: the postdexamethasone cortisol values, the cortisol responses to 125 mg 5-hydroxy-L-tryptophan (L-5-HTP) orally, and the total L-TRP/competing amino acids (CAA) ratio in 64 depressed females. Severely depressed females showed significantly lower values for L-TRP/CAA, significantly higher postdexamethasone cortisol values, and cortisol responses to L-5-HTP as compared with minor depressives. Dexamethasone nonsuppressors showed significantly lower L-TRP/CAA values as compared with suppressors. The cortisol responses to dexamethasone were significantly and negatively correlated with the availability of L-TRP. The cortisol responses to L-5-HTP were not related to either the availability of L-TRP or to the postdexamethasone cortisol values.

5-Hydroxytryptophan↗

PubMed1990

Gastric emptying for solids in patients with duodenal ulcer before and after highly selective vagotomy.

In a series of 31 duodenal ulcer patients (23 males and 8 females), who underwent a highly selective vagotomy, gastric emptying characteristics of a solid meal, labeled with [99mTc]stannous colloid, were assessed before, two weeks and six months after operation. The clinical diagnosis was confirmed by endoscopy and x-ray; failure of treatment with H2 antagonists or antacids during 1-18 (mean 5) years was the direct indication for operative treatment. A temporary delay in gastric emptying is noted two weeks after operation (T1/2: 124 vs 57 min). After six months, gastric emptying time has practically normalized. It appears that this is the result of the preservation of the antropyloric vagal nerve supply. In these patients, a 10% recurrence rate is noted, comparable to the results in the literature. Highly selective vagotomy proves to be a safe and effective procedure with few side effects. It does not impair gastric motility.

Adult↗

PubMed1990

Suppressive effects of dexamethasone on hypothalamic-pituitary-thyroid axis function in depressed patients.

This study investigated the effects of dexamethasone (1 mg orally) on the function of the hypothalamic-pituitary-thyroid (HPT) axis. We determined pre- and post-dexamethasone thyroid-secreting hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), reverse T3 and cortisol levels in 61 depressed inpatients. Dexamethasone had a pronounced suppressive effect on basal TSH and FT3 levels. It had a significant stimulating effect on rT3 levels. No differences were found between melancholic and minor depressives in the effects of dexamethasone on basal TSH, FT3 and rT3. Cortisol non-suppressors were characterized by less suppression of basal TSH values.

Depressive Disorder↗

PubMed1990

The effects of glucocorticoids on the availability of L-tryptophan and tyrosine in the plasma of depressed patients.

There is evidence that a functional deficit of serotonin/noradrenaline and/or of their precursors L-tryptophan (L-TRP)/tyrosine and disorders in the hypothalamic-pituitary-adrenal (HPA) axis are linked to the pathophysiology of severe depressions. Several reports suggest a reciprocal relationship between these neurotransmitters and HPA axis activity. In order to investigate the effect of glucocorticoid excess on the availability of L-TRP and tyrosine to the brain, we measured urinary cortisol (UC) excretion in 24-h urine, and the availability of both amino acids before and after treatment with 1 mg dexamethasone in 26 depressed patients. We found no relationship between UC excretion and the availability of either amino acid. Dexamethasone significantly suppressed the availability of L-TRP (P less than 10(-5] and of tyrosine (P = 0.005). Major depressed patients with melancholia exhibited a significantly lower availability of L-TRP than minor depressives (P = 0.007).

Amino Acids↗

PubMed1990

A revised interpretation of postdexamethasone ACTH and cortisol findings in unipolar depressed females.

Baseline 8 a.m. adrenocorticotropic hormone (ACTH) and cortisol levels and the postdexamethasone ACTH/cortisol values at 8 a.m. and 4 p.m. were determined in 86 depressed females diagnosed using DSM-III criteria. Postdexamethasone ACTH and cortisol values were significantly correlated with their baseline levels. We have shown that regression analysis should be used to assess dexamethasone-induced changes as the residual ACTH and cortisol responses, with the relative effects of the baseline data on the hormone responses being partialed out. The residual ACTH and cortisol values were significantly increased in the most severely depressed females as compared to minor depressives. The residual ACTH responses were markedly correlated with the residual cortisol responses. Cortisol nonsuppression during a depressive episode appeared to be determined by an augmented ACTH escape from dexamethasone suppression. The residual ACTH and cortisol responses could prove to be the most sensitive reflection of the disorder in the negative feedback by dexamethasone on the pituitary. In clinical practice, the ratio ln (postdexamethasone ACTH): ln (basal ACTH) can be used, since this ratio is linearly correlated with the residual ACTH responses.

Adrenocorticotropic Hormone↗

PubMed1990

Clinical subtypes of unipolar depression: Part III. Quantitative differences in various biological markers between the cluster-analytically generated nonvital and vital depression classes.

The hypothalamic-pituitary-adrenal (HPA) axis, the hypothalamic-pituitary-thyroid (HPT) axis, and the availability of L-tryptophan (L-TRP) to the brain were studied in their relationships to (1) 14 depressive symptoms measured by the Structured Clinical Interview for DSM-III-R--Patient Version (SCID) and (2) the cluster-analytically generated vital/nonvital classes. The following biological parameters were measured in 100 depressed females: free thyroxine (FT4), baseline thyroid stimulating hormone (TSH), predexamethasone and postdexamethasone cortisol and adrenocorticotropic hormone (ACTH) values, the circulating levels of total L-TRP, and the L-TRP/sum of competing amino acids ratio. We found that the psychopathological correlates of disorders in the HPA/HPT axis and of a decreased availability of L-TRP were vital symptoms, i.e., distinct quality of mood, nonreactivity, early morning awakening, anorexia-weight loss, and psychomotor disorders. There was no significant relationship between those biological markers and the nonvital symptoms of the SCID inventory for depressive symptoms. However, we did not validate our SCID clustering in vital and nonvital classes by qualitative differences in the biological variables. It was concluded that our nonvital/vital clusters should be regarded as continuous categories with regard to the biological markers studied; these clusters constitute relevant stages in the continuum of progressing biological dysfunction.

Adrenocorticotropic Hormone↗

PubMed1990

The decreased availability of L-tryptophan in depressed females: clinical and biological correlates.

1. The plasma levels of L-tryptophan (L-TRP) and the sum of five competing amino acids (CAA) namely tyrosine, phenylalanine, valine, leucine, isoleucine, were determined in 79 depressed females categorized according to the DSM-III. 2. In these patients the authors measured several parameters known to affect the availability of the above amino acids, i.e. triidothyronine (FT3) and thyroxine (FT4), vanilylmandelic acid (VMA), noradrenaline and adrenaline in 24 hr urine, the sex hormonal and nutritional state. 3. The 1 mg dexamethasone suppression test was performed and the pre and postdexamethasone cortisol and adrenocorticotropic hormone (ACTH) levels were determined at 8 a.m. 4. L-TRP and the ratio L-TRP/CAA were significantly lower in severely depressed females (296.X3, 296.X4) as compared with minor (300.40, 309.00) and simple major depressives (296.X2). The ratio L-TRP/CAA performed well as a clinical tool separating melancholic from minor depression. 5. FT3, FT4, VMA and noradrenaline were significantly increased in the severely depressed females, but these data did not correlate with the availability of L-TRP. Neither baseline cortisol nor the sex hormonal, nor the nutritional state related to the L-TRP data. The ratio L-TRP/CAA was significantly and negatively correlated with the postdexamethasone cortisol and ACTH values.

Adrenocorticotropic Hormone↗

PubMed1990

Positive relationship between the catecholaminergic turnover and the DST results in depression.

In the past some workers have reported positive relationships between indices of noradrenaline activity and measures of hypothalamic-pituitary-adrenal (HPA)-axis function. In order to investigate these relations, the authors measured noradrenaline, adrenaline and vanillylmandelic acid (VMA) in 24 h urine samples of 72 depressed females. Serum adrenocorticotrophic hormone (ACTH) and cortisol concentrations were determined before and after administration of 1 mg of dexamethasone. Cortisol non-suppressors exhibited a significantly higher noradrenaline, adrenaline and VMA excretion as compared to cortisol suppressors. We determined significantly positive correlations between the postdexamethasone cortisol values and the excretion rates of noradrenaline and VMA. These indices of noradrenaline activity correlated neither with the baseline cortisol and ACTH nor with the postdexamethasone ACTH values.

Adrenocorticotropic Hormone↗

PubMed1990

Hypoglycemia owing to inappropriate glucagon secretion treated with a continuous subcutaneous glucagon infusion system.

A selective glucagon deficiency was documented in a 36-year-old female patient suffering from severe hypoglycemic attacks. The extremely low fasting plasma glucagon levels could not be stimulated by hypoglycemia. The increase in plasma glucagon during stimulation with arginine did not prevent hypoglycemia provoked by the simultaneous insulin secretion. Treatment consisting of a continuous sc glucagon infusion system resulted in correction of both postabsorptive and postprandial hypoglycemia. Further lowering of the glucose level during an arginine test could be the hallmark of this hypoglycemic syndrome characterized by an inappropriate glucagon secretion. This case report would indicate that epinephrine cannot prevent hypoglycemia when glucagon release is completely deficient.

Adult↗