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Biomedical subjects

P Blockx

Publications and source records attributed to P Blockx.

At least 55 records · Page 3Linked to original sources
PubMed1989

Hypothalamic-pituitary-adrenal and -thyroid axis dysfunctions and decrements in the availability of L-tryptophan as biological markers of suicidal ideation in major depressed females.

Several neurochemical correlates of suicide were recently detected. Some authors found increased disorders in the hypothalamic-pituitary-adrenal (HPA) and -thyroid (HPT) axes and disturbances in serotonergic neurotransmission in suicidal patients. In order to investigate the biological correlates of suicidal ideation, we measured the following: basal thyrotropin-secreting hormone (TSH), free thyroxine (FT4), pre- and postdexamethasone cortisol, adrenocorticotropic hormone (ACTH) levels, the circulating concentrations of total L-tryptophan (L-TRP) and the ratio between L-TRP and competing amino acids (CAA). The subjects were 17 suicidal and 17 nonsuicidal major depressed females matched for age and severity of illness. We found no significant differences in any of the above-mentioned biological data between patients with suicidal ideation and those without.

Adrenocorticotropic Hormone↗
PubMed1989

Sex-linked differences in cortisol, ACTH and prolactin responses to 5-hydroxy-tryptophan in healthy controls and minor and major depressed patients.

Some researchers have found that the administration of 5-hydroxytryptophan (5-HTP) results in increased cortisol secretion in major depressives but not in healthy controls. Other authors observed gender-related differences in cortisol responses to 5-HTP in major depressives. In order to investigate the pituitary/adrenal responsivity to 5-HTP, the authors measured cortisol, adrenocorticotropic hormone (ACTH) and prolactin (PRL) in 30 healthy controls and in 90 depressed patients; the hormone levels were determined in baseline conditions and 60, 90 and 120 min after 125 mg L-5-HTP (orally, non-enteric coated). We found that healthy men had significantly higher cortisol responses to L-5-HTP than healthy women. In the major depressives with melancholia and/or psychotic features these differences were reversed: women exhibited significantly higher cortisol and PRL responses than men. In the female group the most severely depressed patients had increased cortisol and PRL responses to L-5-HTP. The amplitudes of the cortisol, ACTH and PRL responses to L-5-HTP were significantly and positively correlated. It was concluded that the central serotonergic regulation of ACTH and PRL is significantly different between the sexes and between healthy controls, minor depressives and severely depressed patients.

5-Hydroxytryptophan↗
PubMed1986

Comparative evaluation of the multiple RAST and discrete RAST for inhalant allergy.

With the conventional, discrete RAST various tests are required to detect IgE of different specificities in the same serum. To overcome this problem and to reduce the costs, a multiple RAST with seven different mixtures was compared with the individual mixture constituents and with the 12 individual allergens currently in use in our department. One grass pollen mixture (gx3), two weed pollen mixtures (wx3, wx4), two tree pollen mixtures (tx5, tx6), one mould mixture (mx1) and one epithelial mixture (ex1) were used. A mixture of mites was not evaluated as there is only one important pathogenic organism in our regions (Dermatophagoides pteronyssinus or House dust mite). For grasses the gx3 mixture offered no advantage over the discrete RAST. The weed mixture wx3 was more sensitive than the most common discrete RAST's but at the cost of specificity. The wx4 mixture should not be used because the specificity is too low. The tree mixtures were not significantly more sensitive than the most common individual tree allergens, and were less specific. Mould mixtures should not be used because there is little cross-reactivity between the individual allergens, thus using a mixture would necessitate the subsequent determination of individual allergens, and the number of tests and the cost would be even higher. Neither should a mixture be used for epithelia because one wants to detect allergies to individual allergens. Moreover, the sensitivity of the epithelial mixture was too low. In general, we suggest the use of a limited panel of discrete RAST's instead of mixtures.

Allergens↗
PubMed1986

Binding of serum ferritin to concanavalin A in patients with malignancy.

The percentage non-glycosylated, tissue type ferritin was measured in the serum of 30 cancer patients and 11 normal subjects, as well as in 10 tumour cytosols. As expected, in normal subjects the larger part of serum ferritin corresponded to glycosylated ferritin, and in tumour cytosols the larger part corresponded to non-glycosylated ferritin (tissue ferritin). In all but one cancer patients a significant part of the protein did not bind to Con A, thus behaving as tissue ferritin. The findings obtained suggest release of tissue type, non-glycosylated, ferritin by damaged cells or through abnormal secretion. This relative increase of the non-glycosylated ferritin fraction appears to be very frequently present in cancer, although not specific for it. Assaying for Con A binding may prove to be valuable in the study of malignant disease, and therefore deserves further investigation.

Absorption↗
PubMed1978

The influence of serum folate on urinary excretion of vitamin B12.

It was found that in patients with decreased serum folate concentration, urinary excretion of vitamin B12 was increased in a statistically highly significant way with both oral administration of 58 Co-labeled vitamin B12 and with a 57Co-labeled vitamin B12 intrinsic factor complex. This increased vitamin B12 excretion may account for some false normal Schilling test results. Furthermore, in folate deficiency, the intrinsic factor no longer seems required for vitamin B12 to pass the intestinal wall. It is also questionable whether vitamin B12 absorbed through the intestine under these circumstances could be properly metabolized. Besides statistical evidence, some clinical support for this theory is presented. These findings offer a possible clue for some literature reports that have lacked a satisfactory explanation.

Folic Acid↗
PubMed1978

'Low T3 syndrome' in patients chronically treated with an iodine-containing drug, amiodarone.

Cardiac patients treated with the iodine-containing drug 'amiodarone' undergo a significant iodine overload which can last for months after the drug has been withdrawn. Some patients develop hyperthyroidism and others hypothyroidism. In the hyper- or hypothyroid patients, the indices of thyroid function are modified as usually observed in these situations. In the patients remaining euthyroid while taking amiodarone or after its withdrawal, but still under its influence as shown by the iodine overload, a 'low-T3 syndrome' is observed, this state being characterized by a high total T4, a low free T4, a normal T3 resin uptake, a low total T3, a normal free T3, a high r-T3 and a relative TSH-unresponsiveness to TRH.

Amiodarone↗
PubMed1976

[Amiodarone and thyroid function].

Amiodarone is a drug which is frequently used in cardiology, and which can lead to the appearance of hyper- of hypo-thyroidism in certain cases. A study of the various parameters of thyroid function has shown that these are abnormal in every case treated by this drug, without the biochemical abnormalities necessarily being reflected clinically. The authors outline a method which will allow a distinction to be drawn between patients with a true thyroid malfunction and those whose biochemical results do not appear at first sight to be of any consequence. Regular assays of the T3RIA level are suggested as a means of early detection of thyroid malfunction in patients undergoing treatment with amiodarone.

Amiodarone↗
PubMedDate not supplied

Pituitary and adrenal hormone responsiveness to Synacthen in melancholic subjects versus subjects with minor depression.

Increased adrenal cortex responsiveness to adrenocorticotropic hormone (ACTH) has been suggested to contribute to increased cortisol secretion in dexamethasone nonsuppression and melancholia. To further examine this hypothesis, the following variables were examined in 68 patients with unipolar depression (minor, n = 24; simple major, n = 25; melancholic, n = 19): basal or post-Synacthen [ACTH(1-24), 250 micrograms IV] intact ACTH(1-39), beta-endorphin/beta-lipotropin, cortisol, and androstenedione concentrations, as well as the postdexamethasone (DST) plasma ACTH(1-39) and cortisol values. Melancholic subjects showed significantly higher baseline ACTH(1-39), beta-endorphin/beta-lipotropin, and androstenedione values compared with subjects with minor depression. No significant differences in post-Synacthen cortisol or androstenedione secretion between any of the groups or between [ACTH(1-39) or cortisol] DST nonsuppressors and suppressors were found. No significant relationships between DST and ACTH test results were observed. Abnormally increased post-DST cortisol values in melancholic subjects were highly predicted (> 68% of the variance) by post-DST intact ACTH levels. ACTH(1-39) values were significantly lower after Synacthen administration in melancholic subjects than in subjects with minor depression. These results are not consistent with the hypothesis that melancholia is characterized by an increased adrenocortical responsivity to exogenous ACTH compared with minor depression or that DST nonsuppression is due to adrenal hyperresponsiveness.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Paravertebral schwannoma with high uptake of fluorodeoxyglucose on positron emission tomography.

A paravertebral mass was discovered in a 27-year-old woman, while investigating a painful shoulder and arm. CT, MRI and fine needle aspiration cytology (FNAC) pointed in the direction of a benign mass, but positron emission tomography (PET) showed a high uptake of [(18)F]fluorodeoxyglucose (FDG), which was indicative of a malignant lesion. Pathological analysis of the thoracoscopically resected tumour gave us the final diagnosis of a benign schwannoma. This report demonstrates that a high uptake of FDG in a non-malignant mediastinal tumour is possible.

Adult↗
PubMedDate not supplied

Clinical profile of a new monoclonal antibody-based immunoassay for tissue polypeptide antigen.

Our preliminary evaluation of a new monoclonal antibody-based assay for tissue polypeptide antigen (TPA) has shown it to be clinically equivalent to the polyclonal antibody-based assay for TPA. The new assay (TPA-M) employs three monoclonal antibodies to epitopes on cytokeratins 8, 18 and 19. This multicenter, multinational study included 266 patients with newly diagnosed carcinomas of the lung, breast, large bowel and urinary bladder. TPA values from the two assays were compared with three other cytokeratin markers (TPS, CYFRA 21-1 and TPACyk) and with the established reference markers for these malignancies (CEA and NSE for lung, CA 15-3 for breast, CEA and CA 19-9 for colorectal tumors). Analysis of receiver operating characteristic (ROC) curves in lung, colorectal and bladder cancer showed similar sensitivities for the two assays, ranging from 50% to 80% with a specificity of 95%. In breast cancer all the markers studied showed poor sensitivity. However, TPA determination by either method could discriminate advanced stage (stages III and IV) from early stage disease (stages 0 to II). TPA showed similar discriminating ability in bladder cancer. On the basis of the results obtained in our patient series, it seems that of the cytokeratin markers studied, TPA and TPA-M are the most sensitive and offer a wide range of clinical applications.

Antibodies, Monoclonal↗
PubMedDate not supplied

Gastric emptying rate for solid and for liquid test meals in patients with dyspeptic symptoms after partial gastrectomy and after vagotomy followed by partial gastrectomy.

BACKGROUND/AIMS: Gastric emptying rate for solid and for liquid test meals was investigated retrospectively in patients with longstanding epigastric distress after partial gastrectomy, either as primary treatment or after failure of vagotomy for peptic ulcer in order to find an explanation for the postoperative symptoms. METHODOLOGY: Radionuclide-labeled liquid and solid test meals were used to evaluate gastric emptying rate, at least one year after surgery. RESULTS: The lag phase for liquid test meals disappeared in all operated patients. Partial gastrectomy usually lead to fast emptying but this resective procedure, if performed after vagotomy, lead to stasis in a significant number of patients. Gastric emptying rate for solids increased in only a few of these symptomatic patients. In most of them however, there was a normal to decreased emptying rate. If a vagotomy had preceded the resective procedure, gastric emptying rate decreased significantly. CONCLUSIONS: In all these symptomatic patients, gastric emptying had been disturbed for at least one type of test meal. This makes investigation for both meals necessary, especially since there is a lack of correlation. Furthermore, if vagotomy fails to prevent ulcer recurrence, one should carefully consider all options before performing partial gastrectomy since gastric emptying rate after these consecutive procedures worsens considerably.

Adult↗
PubMedDate not supplied

The effect of stress on gastric emptying rate measured with a radionuclide tracer.

BACKGROUND/AIMS: Stress can delay gastric emptying rate. This phenomenon has not yet been investigated with a physiological solid test meal or a regional analysis. METHODOLOGY: We investigated the gastric emptying rate in beagle dogs using a radio-labeled solid test meal and a gamma camera. The transport to an unknown environment served as a stress stimulus. This offers the advantage to mimic fairly well the clinical situation just before a diagnostic or therapeutic procedure. Control values were obtained after the third investigation, in which all dogs were accustomed to the environment. RESULTS: Regional analysis of the emptying curves from the whole gastric region revealed that the length of the lag phase increased with stress, but the post-initial emptying rate remained unchanged. Emptying of the fundus changed hardly, but the antropyloral motor activity decreased during stress. CONCLUSIONS: Gastric emptying rate is impeded during stress. It is necessary to limit the unnatural stress-stimuli, in order to mimic the clinical situation. Measurement techniques that influence directly gastric emptying or act as a stress-stimulus by themselves are undesirable. A radionuclide solid test meal is preferable and a regional analysis reveals the impairment of the antral motility as the mechanism of the delay of gastric emptying.

Animals↗