Studies on the insulinomimetic effects of benzylamine, exogenous substrate of semicarbazide-sensitive amine oxidase enzyme in streptozotocin induced diabetic rats

Semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO) is believed to be a bifunctional membrane protein. It is localized extracellularly and preferentially oxidizes short chain primary amines to aldehydes, hydrogen peroxide and ammonia, but also functions as an adhesion molecule, which is involved in leukocyte migration. Serum SSAO activity is increased in diabetic patients and animals and the aldehydes formed in the enzyme reaction may contribute to vascular damage. However, administration of exogenous substrates has been shown to improve glucose tolerance and reduce hyperglycaemia in diabetic animals. Hydrogen peroxide and/or its vanadate complexes have been suggested responsible for these effects. Streptozotocin induced diabetic rats were treated with benzylamine (BZA) +/- vanadate (V) or insulin. In contrast to insulin, BZA + V treatment did not reduce HbA(1C) levels. However, it reduced the elevated serum SSAO activity, decreased the accumulation of advanced-glycation end products and increased the bioavailability of nitric oxide in diabetic animals, similarly to insulin. BZA alone did not affect any of these parameters.

Evaluation of pheromones and a new trap for monitoring Agriotes lineatus and Agriotes obscurus in the Fraser Valley of British Columbia

A prototype ground-based pheromone trap design, baited with various pheromone lures, was field tested for effectiveness in trapping male Agriotes obscurus and Agriotes lineatus click beetles in British Columbia. Pheromone dispensers containing geranyl octanoate and geranyl hexanoate in a 1:1 ratio caught the greatest numbers of A. obscurus, whereas those containing geranyl octanoate and geranyl butanoate in a 9 or 10:1 ratio caught high numbers of A. lineatus. Some differences in A. obscurus attraction to traps were observed between dispensers according to the manufacturer and the number of dispensers deployed in traps. The trap design and optimal pheromone dispensers tested would be suitable for monitoring or surveying A. obscurus and A. lineatus populations in North America.

Patterns of violent aggression-induced brain c-fos expression in male mice selected for aggressiveness

Mice selected for aggressiveness (long and short attack latency mice; LALs and SALs, respectively) constitute a useful tool in studying the neural background of aggressive behavior, especially so as the SAL strain shows violent forms of aggressiveness that appear abnormal in many respects. By using c-Fos staining as a marker of neuronal activation, we show here that agonistic encounters result in different activation patterns in LAL and SAL mice. In LALs, agonistic encounters activated the lateral septum, bed nucleus of stria terminalis, medial amygdala, paraventricular nucleus of the hypothalamus, anterior hypothalamic nucleus and tuber cinereum area (both being analogous with the rat hypothalamic attack area), dorsolateral periaqueductal gray, and locus coeruleus. This pattern is similar with that seen in the territorial aggression of male mice, rats and hamsters, and non-lactating female mice. SALs showed strong fight-induced activations in the central amygdala and lateral/ventrolateral periaqueductal gray. In this strain, no activation was seen in the lateral septum and the dorsolateral periaqueductal gray. This pattern is similar with that seen in other models of violent aggression, e.g., in attacks induced by hypothalamic stimulation in rats, quiet biting in cats, lactating female mice, and hypoarousal-driven abnormal aggression in rats. We suggest here that the excessive activation of the central amygdala and lateral/ventrolateral periaqueductal gray--accompanied by a smaller activation of the septum and dorsolateral periaqueductal gray--underlay the expression of violent attacks under various circumstances.

Speech activation spect and plasticity of language networks

Neuronal activity might be measured by regional cerebral blood flow (rCBF) Single Photon Emission Computed Tomography (SPECT) as there is a close relationship between neuronal activity and rCBF changes. In order to study the hemispheric dominance for language and the plasticity of language networks by measuring the rCBF rest and language activation SPECT studies were performed in the presurgical evaluation of ten right-handed and two left handed patients with brain lesions of the dominant hemisphere. A special group of hemisphere-specific neuropsychologic tasks were used for activation, after a proper psychologic conditioning. The rCBF results were calculated by comparing the rest and activation SPECT data using a special regions of interest program and asymmetry index (AI). We compared the results of speech-activation to the results of clinical, morphological (MRI), and postoperative data. In controls, significant activation was found in Brodmann's area 44 and 45, contralateral cerebellum, superior middle and posterior temporal gyrus. In patients, additional regions of activation were seen in contralateral frontal and temporal regions, and in ipsilateral temporal region. AIs of the cerebellum demonstrated a negative correlation with hemispheric dominance for language. In conclusion, significant changes in rCBF in or adjacent to the eloquent areas with various patterns of rCBF changes of the additional regions demonstrate the close relationship between neuronal activity and cerebral blood flow, that can be measured by SPECT.

Enhanced corneal compensation for scanning laser polarimetry on eyes with atypical polarisation pattern

AIM

To investigate the potential advantage of an enhanced corneal compensation algorithm (ECC) compared with variable corneal compensation (VCC) in the analysis of scanning laser polarimetric (SLP) images with atypical retardation pattern (ARP).

METHODS

SLP-VCC images with ARP (typical scan score (TSS) <80) of one eye of each of 27 glaucoma patients and 19 healthy subjects were compared with the corresponding SLP-ECC images obtained at the same session.

RESULTS

ARP was present in 10.4% of the normals and 15.5% of the glaucoma patients imaged with SLP-VCC over 9 months. In both groups TSS was higher for ECC than for VCC (p<0.001). In glaucoma TSNIT, superior and inferior average thickness values were significantly lower, and TSNIT (measuring ellipse around the optic nerve head in the four (temporal, superior, nasal, inferior) quadrants) standard deviation was significantly higher with ECC than with VCC (p<0.001). In the normal group nerve fibre indicator (NFI) was lower with ECC than with VCC (p=0.007). TSNIT average was smaller and TSNIT standard deviation was higher with ECC (p<0.001). Superior and inferior average thickness did not differ between VCC and ECC in the normal group.

CONCLUSIONS

The new ECC software substantially improves polarimetric image analysis on eyes showing atypical polarisation pattern.

Clinical and biochemical features of sporadic and hereditary phaeochromocytomas: an analysis of 41 cases investigated in a single endocrine centre

The aims of this study were to estimate the prevalence of phaeochromocytomas among adrenal tumours and to analyse the clinical and biochemical features of sporadic and hereditary tumours. Our series of 609 adrenal tumours evaluated between January 1995 and July 2003 was reviewed. Catecholamine content in phaeochromocytoma tissues was also determined and correlated with clinical behaviour and biochemical parameters of patients. Forty-one (6.7%) of the 609 patients had phaeochromocytomas, of which 28 were sporadic (25 benign and three malignant) and 13 (all benign) were associated with hereditary diseases (multiple endocrine neoplasia type 2A in seven cases from four unrelated families carrying mutations of the RET gene, von Hippel-Lindau disease in two unrelated cases with mutations of the VHL gene, and type 1 neurofibromatosis in four unrelated cases). Bilateral tumours were found in three patients with hereditary syndromes and in one sporadic case. Tumour diameter was slightly but not significantly greater in patients with hereditary than in those with sporadic tumours. Systolic but not diastolic blood pressure was significantly higher in patients with sporadic compared with those with hereditary tumours, but comparison of other clinical data and biochemical parameters indicated an absence of significant differences in the mean age, presenting symptoms, heart rate, or fasting serum glucose levels. Tissue catecholamine content measured in 8 sporadic and 5 hereditary phaeochromocytomas was highly variable and it failed to show significant differences between hereditary and sporadic tumours. These results indicate a high proportion of hereditary diseases among patients with phaeochromocytomas. Genetic and clinical testing for hereditary diseases may be of great help to offer an appropriate treatment, follow-up and family screening for these patients.

Effect of single doses of dexamethasone and adrenocorticotrop hormone on serum bone markers in healthy subjects and in patients with adrenal incidentalomas and Cushing's syndrome

The aim of the present study was to explore whether short-term changes in glucocorticoid activity which occur during dynamic testing of the pituitary adrenal axis with dexamethasone, ACTH, or metyrapone could have an effect on serum osteocalcin (OC) and beta-crosslaps (beta-CTx) concentrations in healthy subjects, in patients with adrenal incidentalomas and in those with Cushing's syndrome. The study included 40 healthy subjects (35 women and 5 men, age range 18-69 yr), 49 patients with adrenal incidentalomas (34 women and 15 men, age range 19-77 yr) and 8 patients with Cushing's syndrome (5 cortisol-producing adenomas and 3 pituitary-dependent Cushing's syndrome, 3 women and 5 men, age range 19-70 yr). Serum OC and beta-CTx concentrations were determined with electrochemoluminescent immunoassays at midnight, after an overnight fast between 08:00 and 09:00 h, after an overnight dexamethasone test (1 mg, orally) and after a single dose of metyrapone (30 mg/kg, orally). In healthy subjects and in patients with adrenal incidentalomas, serum bone marker concentrations were also measured after a single dose of ACTH injection (Cortrosyn depot, 1 mg im). Patients with Cushing's syndrome, but not those with adrenal incidentalomas, showed significantly lower serum OC at midnight (18.5+/-12 ng/ml, mean+/-SD) and between 08:00 and 09:00 h (17.7+/-9.6 ng/ml) compared to corresponding values obtained in healthy subjects (24.5+/-7.0 and 28.3+/-12.2 ng/ml, respectively). Serum OC concentrations were significantly decreased after a single dose of 1-mg dexamethasone in healthy subjects (from 28.3+/-12.2 to 21.8+/-9.5 ng/ml) and in patients with adrenal incidentalomas (from 29.8+/-15.9 to 24.1+/-14.1 ng/ml), whereas serum OC concentrations remained unchanged in patients with Cushing's syndrome. In addition, serum OC concentrations were even more markedly decreased after a single dose of ACTH injection in both healthy subjects (12.5+/-4.6 ng/ml) and in patients with adrenal incidentalomas (12.2+/-6.5 ng/ml). By contrast, metyrapone administration failed to induce significant changes in OC levels. There were no significant differences in beta-CTx concentrations between the three groups or after drug treatments. Thus, serum OC levels should be interpreted with caution when obtained during testing of the pituitary-adrenal axis with dexamethasone or ACTH.

Origin of the bursal secretory dendritic cell

The origin of vimentin-positive secretory dendritic cells of the bursa of Fabricius was studied by chick-quail chimera, parabiosis and immunohistochemistry using species-specific monoclonal antibodies. Quail bursal primordia of different ages were transferred to coelomic cavity of 3-day-old chicken embryos and further incubated for 18 days. In transplanted quail bursas the secretory dendritic cells of chicken and quail origin were detected by double staining of vimentin plus 74.3 and vimentin plus QCPN monoclonal antibodies, respectively. In bursal primordia of 5- and 6-day-old quail embryos both dendritic cells and B cells were of host, i.e. chicken origin. Mixed dendritic cell population of quail and chick origin emerged in chimeric birds of 6.5 days of age. In quail embryos transplanted at 7 and 8 days of age both dendritic cells and B cells were mixed i.e. of chicken and quail origin. Bursal secretory dendritic cells and medullary epithelial cells create "dendro-epithelial tissue" to receive pre-B cells. Colonization of dendro-epithelial tissue by pre-B cells initiates at day 7, thus the colonization of bursal anlage by blood-borne cells is a two-step process; entering of dendritic cells at day 6.5 is followed by that of B cells at day 7 and afterwards. It is discussed that bursal secretory dendritic cells and their product are key elements of bursal function therefore the mammalian bursa equivalent organ might be represented by a cell, which is analogous with the bursal secretory dendritic cell.

The effect of gender and age on growth hormone replacement in growth hormone-deficient patients

We analyzed the effect of growth hormone replacement therapy (36 months) analyzed at a dose adjusted to maintain serum insulin-like growth factor-I level between the median and the upper end of the age-related reference range on bone mineral density, body composition, and carbohydrate metabolism with respect to gender and age in 20 adult patients (9 women, 11 men, mean age: 43 years, range: 21-61 years). The lumbar and femoral T-score was increased after 12 and after 18 months of therapy respectively in men (p < 0.001 and p = 0.002), but did not changed significantly in women. The increase of femoral T-score was greater in young men (< or = 45 years, n = 6) than old men (> 45 years, n = 5, p < 0.001). Body fat was lower in men than in women after 6 months (p = 0.002). The waist/hip ratio only decreased in women (p = 0.044). The waist circumference decreased in both genders after 6 months of therapy (p < 0.001), but more markedly in females than in males (p < 0.05). The sum of skinfold thicknesses was reduced in males after 6 months of therapy (p < 0.001). Changes in body composition parameters measured were independent of age. The glycosylated hemoglobin increased without sex or age difference after 12 months of initiation of therapy (p < 0.001), but fasting glucose and insulin levels did not change during the therapy. Our results indicate that the effect of growth hormone replacement on bone mineral content in adults is age- and gender-dependent, gender dependent on body composition, but independent of age and gender on carbohydrate metabolism.

Calcium Metabolism and Endocrine Functions in a Family with Familial Hypocalciuric Hypercalcemia

OBJECTIVE

We report two Hungarian patients with familial hypocalciuric hypercalcemia (FHH) caused by a mutation of the calcium-sensing receptor (CaSR) at codon 55. The proband and her father were heterozygous for this mutation.

DESIGN

We performed detailed clinical and laboratory assessments of this family to characterize the effects of CaSR mutation on several endocrine organs expressing CaSR.

RESULTS

Interestingly, we could not detect any failure in the function of any tissues we examined, except in serum calcium levels.

CONCLUSIONS

To our knowledge, this has been the first report from Eastern and Central Europe showing P55 L mutation of the CaSR, as well as the first publication discussing the effect of this mutation on several endocrine systems containing CASR.

Effects of 24 months of growth hormone (GH) treatment on serum carboxylated and undercarboxylated osteocalcin levels in GH-deficient adults

We studied the effect of growth hormone (GH) replacement on bone mineral density (BMD) and some parameters of bone metabolism, including undercarboxylated osteocalcin (ucOC), an independent predictive marker of fracture risk, which has not been previously determined or compared during GH treatment. Measurements were performed at baseline and after 6, 12, 18 and 24 months of the initiation of the GH therapy in 21 adult patients with GH deficiency. Significant increases were observed in BMD after 1 year at the lumbar spine and after 1.5 years at the femoral neck. Serum total OC and carboxylated (c) OC increased and reached the maximum at 6 months, but the values remained over the baseline at both 12 and 18 months. The ucOC:total OC ratio changed contrarily: it decreased at 6 months, then increased again and reached the baseline level during the next 18 months. Serum calcium (Ca), phosphate (P) and total alkaline phosphatase (ALP) levels increased after 6 months, thereafter the Ca and P values decreased, while the total ALP remained elevated until 12 months. Serum parathormone decreased at 12 months and increased again thereafter. GH replacement therapy is associated with improvement of ucOC, a marker of fracture risk, which in addition to the increase of BMD, might contribute to the beneficial effect of GH replacement therapy on bone metabolism.

Plasma 6beta-hydroxycortisol measurements for assessing altered hepatic drug metabolizing enzyme activity

To study the usefulness of 6beta-hydroxycortisol (6betaOHF) measurements for assessing hepatic drug metabolizing enzyme activity, plasma 6betaOHF and cortisol were measured in 22 patients with alcoholic liver disease after at least 2 weeks of alcohol abstinence, in 5 patients with severe Cushing's syndrome and in 12 healthy non-drinker subjects. Blood samples were drawn under resting conditions during midnight, in the morning at 0800 h, after a 1-mg overnight dexamethasone test and after ACTH administration. Plasma cortisol and 6betaOHF were determined with radioimmunoassay. In patients with alcoholic liver disease, the plasma cortisol levels at midnight and 0800 h, as well as after the administration of dexamethasone and ACTH were not different from corresponding values measured in non-drinker controls. In addition, these patients with alcoholic liver disease had similar plasma 6betaOHF levels at midnight, 0800 h and after dexamethasone administration as compared to corresponding values in controls. By contrast, ACTH administration in patients with alcoholic liver disease resulted in a significantly (p<0.05) larger increase of plasma 6betaOHF (from 106 +/- 22 to 1102 +/- 106 ng/dl, mean +/- SE) as compared to that found in controls (from 74 +/- 3 to 337 +/- 76 ng/dl). The markedly increased 6betaOHF response to ACTH administration in patients with alcoholic liver disease was similar to that measured in patients with severe Cushing's syndrome, in whom increased and non-suppressible plasma cortisol levels were accompanied by markedly elevated plasma 6betaOHF levels. These results indicate that alcohol abstinence in patients with alcoholic liver disease is associated with an exaggerated 6betaOHF response to ACTH and that this abnormality may prove to be a clinically useful parameter for a sensitive detection of altered drug metabolism present in these patients.

Parathyroid surgical failures with misleading falls of intraoperative parathyroid hormone levels

According to earlier reports, a decrease below 50% of baseline of intraoperative PTH levels measured 5 min after resection of the parathyroid adenoma predicts a cure of hyperparathyroidism. To reveal previously unrecognized pitfalls of intraoperative PTH measurements, we reviewed surgical failures in our series of parathyroidectomies combined with intraoperative PTH sampling. PTH measurements were performed in 251 patients with primary hyperparathyroidism (PHPT) between November 1999 and December 2002. PHPT due to parathyroid hyperplasia were found in 8 cases, double parathyroid adenomas in 6 cases, parathyroid carcinoma in 1 case and single parathyroid adenomas in 236 cases, all confirmed by histological examination. Of the 236 cases of single adenomas, initial surgery failed to cure PHPT in 4 patients. In 3 patients a false-positive decrease of intraoperative PTH (from 269 to 40 pg/ml, from 211 to 27 pg/ml, and from 140 to 59 pg/ml) was observed, whereas in the fourth patient a true-negative decrease of intraoperative PTH (from 758 to 401 pg/ml) was mistakenly interpreted as indication for a cure of PHPT. In each of the 4 patients in whom initial surgery failed the intervention included thyroid surgery and reoperative parathyroid surgery resulted in a permanent cure of PHPT. These observations support the possibility that thyroid surgery may compromise the blood supply of parathyroid adenomas resulting in a misleading drop of intraoperative PTH levels. Therefore, a careful evaluation of intraoperative PTH levels and, perhaps, other intraoperative aids such as histological evaluation of frozen sections are recommended when parathyroid surgery is combined with simultaneous thyroid intervention.

Plasma and salivary 6beta-hydroxycortisol measurements for assessing adrenocortical activity in patients with adrenocortical adenomas

The aim of this study was to examine and compare the potential usefulness of plasma and salivary 6beta-hydroxycortisol measurements for assessing adrenocortical activity in patients with adrenocortical adenomas. Plasma and salivary cortisol as well as 6beta-hydroxycortisol determinations were performed by radioimmunoassay after extraction with ethyl acetate followed by chromatographic separation using a modified paper chromatographic system. Samples were obtained from 36 control subjects and 37 patients with non-hyperfunctioning adrenocortical adenomas in the morning at 8 a.m. after a low-dose of dexamethasone and after stimulation with synthetic depot ACTH. Basal and post-dexamethasone hormone levels were also measured in plasma and salivary samples of 4 patients with Cushing's syndrome from adrenal adenomas. In the baseline state, patients with non-hyperfunctioning adrenocortical adenomas had significantly higher plasma and salivary 6beta-hydroxycortisol levels (mean+/-SE, 79.0+/-7 and 17.1+/-2.2 ng/dl, respectively) compared to those measured in controls (62.0+/-4 and 7.7+/-0.6 ng/dl, respectively), whereas baseline plasma and salivary cortisol levels (9.6+/-0.5 microg/dl and 342+/-39 ng/dl, respectively) were similar to those measured in the control group (9.9+/-0.4 microg/dl and 366+/-24 ng/dl, respectively). In all groups, the changes in plasma and salivary 6beta-hydroxycortisol concentrations after dexamethasone suppression and ACTH stimulation were similar to the changes in plasma and salivary cortisol levels, although the differing ratios of 6betaOHF to cortisol indicated potentially important variations in the induction of 6beta-hydroxylase activity between the three groups. In patients with Cushing's syndrome, baseline plasma and salivary 6beta-hydroxycortisol concentrations (754+/-444 and 104+/-88 ng/dl, respectively) were more markedly increased than plasma and salivary cortisol levels (24.8+/-6.7 microg/dl and 1100+/-184 ng/dl, respectively), and all remained non-suppressible after dexamethasone administration. These results suggests that plasma and salivary 6beta-hydroxycortisol determinations may precisely detect not only overt increases of cortisol secretion in patients with Cushing's syndrome but also mild glucocorticoid overproduction presumably present in patients with non-hyperfunctioning adrenocortical tumors.

Segregation of the V804L mutation and S836S polymorphism of exon 14 of the RET gene in an extended kindred with familial medullary thyroid cancer

In multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid cancer (FMTC), the majority of germline mutations are restricted to specific positions in exons 10 and 11 of the RET gene. However, germline mutations may very occasionally occur in other exons, including exon 14 of the RET gene. Interestingly, an increased frequency of a rare germline sequence variant of the RET exon 14, S836S, has been detected in patients with sporadic medullary thyroid cancer (MTC), and this variant has been proposed to play a role in the genesis of MTC and, perhaps, FMTC. In this study we report the segregation of a germline V804L mutation and a germline sequence variant S836S in exon 14 of the RET gene in an extended Hungarian FMTC kindred comprising 80 individuals of four generations. Molecular analysis of the RET gene was performed by direct DNA sequencing in 23 family members, of whom 12 had the V804L mutation, three had the V804L mutation and S836S polymorphism in separate alleles, and six had the S836S polymorphism, all in heterozygous forms. Two of the family members had neither mutation nor polymorphism of the RET gene. Three of the family members who had the V804L mutation and one member who could not be tested for mutation were operated for non-metastatic MTC, while one member with MTC who had the V804L mutation refused surgery. In all patients affected with MTC, the disease developed relatively late in life and never caused death. None of the other family members carrying the V804L mutation and/or the S836S polymorphism had clinical or biochemical evidence of MTC. These observations suggest that the co-existence of the V804L mutation and S836S polymorphism in separate alleles does not seem to aggravate the relatively low-risk disease phenotype characteristic in most patients with codon 804 mutations of the RET exon 14.

Ovarian steroid cell tumor and a contralateral ovarian thecoma in a postmenopausal woman with severe hyperandrogenism

A 49-year-old woman presented with rapidly progressing hirsutism, receding hairline, male-pattern baldness and deepening of voice, which had developed over the past 2 years. Hormonal evaluation showed a markedly elevated serum testosterone level (418 ng/dl) and no evidence of increased production of cortisol, dehydroepiandrosterone, dehydroepiadrosterone-sulfate, androstenedione, or 17-hydroxyprogesterone. Transvaginal ultrasound examination suggested the presence of a small mass within the left ovary, but all other radiological studies, including adrenal and ovarian computed tomography, magnetic resonance imaging, radio-labelled cholesterol scintigraphy and positron emission tomography, were negative. Subsequently, bilateral selective venous sampling showed a marked testosterone gradient in the right ovarian vein. Bilateral salpingo-oophorectomy was performed (the patient had had a previous vaginal hysterectomy), and histopathological examination revealed a 10-mm steroid cell tumor within the right ovary and a 15-mm thecal cell tumor within the left ovary. The postoperative serum testosterone level returned to normal and the patient showed a slow regression of clinical symptoms. The simultaneous occurrence of a virilizing ovarian steroid cell tumor and an apparently non-functioning thecoma within the contralateral ovary emphasizes the potential pitfalls that may exist in the preoperative evaluation of patients with markedly increased testosterone production.

Allelic variation at the interleukin 1beta gene is associated with decreased bone mass in patients with inflammatory bowel diseases

BACKGROUND

Interleukin 1beta (IL-1beta) and its natural antagonist have been implicated in the pathogenesis of inflammatory bowel disease (IBD). Both cytokines influence bone formation. IL-1beta stimulates osteoclast activity while interleukin 1 receptor antagonist (IL-1ra) enhances bone formation.

AIMS

To determine whether the decreased bone mass in IBD is related to gene polymorphisms coding for IL-1beta and IL-1ra, and thus identify patients with an increased risk.

METHODS

Bone mineral densitometry was performed at the femoral neck, lumbar spine, and the distal third of the radius in 75 IBD patients (34 men/41 women; 40.3 (1.6) years) and in 58 healthy controls (HC; 28 men/30 women; 32.4 (1.2) years). Values were correlated with the TaqI and AvaI gene polymorphisms in the IL1B and the variable number of tandem repeats gene polymorphism in the IL1RN gene.

RESULTS

In IBD patients, but not in HC, carriers of allele 2 at the AvaI gene polymorphism (IL1B-511*2) had significantly lower Z scores at the lumbar spine (-0.82 (0.13) v -0.29 (0.21) p=0.03) and the femoral neck (-0.59 (0.14) v 0.15 (0.19); p=0.003) than non-carriers. These patients also had a higher risk for osteopenia or osteoporosis at the femoral neck (odds ratio 3.63 (95% confidence interval 0.95-13.93)). No association was found between bone mass and the other gene polymorphisms analysed in IBD patients or in HC.

CONCLUSIONS

Our results suggest that genetic variability may be a major determinant of bone loss in IBD. Carriers of IL1B-511*2, who are hypersecretors of IL-1beta, have a higher risk of presenting with low bone mass in IBD. Screening for this allele may contribute to determination of the risk of bone loss at the time of disease onset.

[Dual-energy x-ray absorptiometry and quantitative ultrasound bone density examinations in primary hyperparathyroidism]

The aim of this study was the analysis and comparison of bone density data obtained by dual-energy X-ray absorptiometry (DEXA) and quantitative ultrasound (QUS) and the follow up of bone density after parathyroidectomy of our patients with primary hyperparathyroidism. The authors performed bone mineral density (BMD) measurements using DEXA (Hologic QDR 4500 C) and QUS (Lunar Achilles Plus) devices in 22 patients with primary hyperparathyroidism between 1997 and 1999 (19 sporadic, 1 MEN 1., 2 MEN II.). Fifteen patients underwent parathyroidectomy (13 adenoma, 2 carcinoma). According to DEXA measurements all patients had osteoporosis. The lowest bone mineral density was detected at the wrist: the mean t-score was -4.00 +/- 1.79. After parathyroidectomy nine patients were followed for a mean of 12.8 months. After one year following surgery the most significant increase in BMD was 14.6%. The QUS values did not correlate with the DEXA data before the operation and no significant changes in stiffness were detected after surgery. The QUS values do not reflect the severity of the BMD decrease by DEXA in patients with primary hyperparathyroidism.

Factors derived from adrenals are required for activation of cardiac gene expression in angiotensin II-induced hypertension

The mechanisms mediating the activation of cardiac gene expression during pressure overload are not fully understood. We examined whether angiotensin II-induced activation of ventricular gene expression is related to blood pressure and ventricular mass or requires other factors by infusing angiotensin II in sham-operated and adrenalectomized rats. In sham-operated rats, angiotensin II (33 microg/kg x h, sc) produced a significant increase in mean arterial pressure (measured by telemetry) within 3 h. Mean arterial pressure (up to 45 h) and the increase in left ventricular hypertrophy in adrenalectomized rats during angiotensin II infusion were similar to those in sham-operated rats. Angiotensin II produced 3.6-fold (P < 0.01) and 20.4-fold (P < 0.001) increases in ventricular atrial natriuretic peptide mRNA levels at 12 and 72 h, respectively. Angiotensin II infusion for 12 h also significantly increased the ventricular mRNA levels of B-type natriuretic peptide (5.2-fold) and adrenomedullin (1.4-fold). Adrenalectomy either abolished (atrial natriuretic peptide and adrenomedullin) or blunted (B-type natriuretic peptide) the early activation of ventricular gene expression by angiotensin II. The baseline synthesis of atrial natriuretic peptide, B-type natriuretic peptide, and adrenomedullin in the ventricle remained unchanged in adrenalectomized rats. In conclusion, our results indicate that factors derived from the adrenals are required for angiotensin II-induced early activation of cardiac gene expression.

Synthesis of and a comparative study on the inhibition of muscle and liver glycogen phosphorylases by epimeric pairs of d-gluco- and d-xylopyranosylidene-spiro-(thio)hydantoins and N-(d-glucopyranosyl) amides

D-Gluco- and D-xylopyranosylidene-spiro-hydantoins and -thiohydantoins were prepared from the parent sugars in a six-step, highly chemo-, regio-, and stereoselective procedure. In the key step of the syntheses C-(1-bromo-1-deoxy-beta-D-glycopyranosyl)formamides were reacted with cyanate ion to give spiro-hydantoins with a retained configuration at the anomeric center as the major products. On the other hand, thiocyanate ions gave spiro-thiohydantoins with an inverted anomeric carbon as the only products. On the basis of radical inhibition studies, a mechanistic rationale was proposed to explain this unique stereoselectivity and the formation of C-(1-hydroxy-beta-D-glycopyranosyl)formamides as byproducts. Enzyme assays with a and b forms of muscle and liver glycogen phosphorylases showed spiro-hydantoin 12 and spiro-thiohydantoin 14 to be the best and equipotent inhibitors with K(i) values in the low micromolar range. The study of epimeric pairs of D-gluco and D-xylo configurated spiro-hydantoins and N-(D-glucopyranosyl)amides corroborated the role of specific hydrogen bridges in binding the inhibitors to the enzyme.

[Serum bone marker measurements in bone metabolism disorders associated with inflammatory bowel diseases]

Patients with inflammatory bowel disease (IBD) have decreased bone mineral density (BMD), which is usually much more remarkable in patients with Crohn's disease (CD) than those with ulcerative colitis (UC). The aim of the present study was to investigate the usefulness of serum beta-Crosslaps (bCL) and osteocalcin (OC) determinations to assess bone metabolism in patients with IBD. Forty-nine patients with IBD (23 UC, 26 CD) and 46 healthy controls were studied. Serum bCL and OC were measured by Elecsys immunoassay. Compared to controls (0.275 +/- 0.14 ng/ml) the mean bCL concentration was significantly higher in the CD (mean = 0.489 +/- 0.25 ng/ml; p < 0.001) and UC groups (mean = 0.439 +/- 0.3 ng/ml; p < 0.01). The mean OC concentration was significantly higher in the CD group (28.52 +/- 14.75 ng/ml) than in controls (21.42 +/- 7.43 ng/ml) but OC level was not significantly increased in the UC group (24.89 +/- 15.08 ng/ml). There was no significant difference in bCL or OC concentrations between the CD and UC groups. These results indicate that the accelerated bone resorption is not associated with increased bone formation in patients with IBD. These two marker of the bone metabolism could be a good laboratory parameter of bone pathology in patients with IBD, especially in CD.

[Adrenomedullin under physiologic and pathologic conditions]

Adrenomedullin (AM) is a novel 52-aminoacid-peptide hormone, originally isolated from human phaeocromocytoma. Adrenomedullin acts as a local autocrine and/or paracrine vasoactive hormone and has vasodilator and blood lowering properties, but its exact role is still uncertain. Adrenomedullin is considered to play an important endocrine role in various tissues maintaining the electrolyte and fluid homeostasis. Its normal plasma concentration is low. In hypertension, chronic renal failure and congestive heart failure its plasma concentration increases parallel to the seriousness of the disease. It is assumed that this peptide may be important under pathologic conditions compensating the effects of the vasoconstrictor molecules. Till now, investigations have proved that in diabetic angiopathies the levels and the production of vasoconstrictor factors and adrenomedullin were increased, while, those of other relaxing substances including nitrogenoxid were decreased. It is still uncertain whether increased release of adrenomedullin in diabetes is a compensatory mechanism or a coincidental event. Although, the precise role of adrenomedullin in the pathogenesis of diabetic complications is still to be elucidated, the elevated concentration of adrenomedullin in diabetes--which influences the vascular functions--let us speculate that there might be a certain interaction between adrenomedullin induction and vascular functions in diabetes. Thus, the induction of vascular adrenomedullin could be a new target of a therapeutic approach to the diabetic complications.

[Significance of trypsinogen gene mutations in the etiology of hereditary pancreatitis]

Hereditary, chronic pancreatitis is an autosomal dominant genetic disorder, frequently associated with two point mutations in the cationic trypsinogen gene. The mutations result in characteristic changes in the amino-acid sequence of trypsinogen: an arginine residue at position 117 is changed to histidine (Arg117-->His) or an asparagine residue at position 21 is replaced by isoleucine (Asn21-->Ile). Current opinion on the pathogenesis of hereditary pancreatitis suggests that the mutations lead to increased trypsin activity in the pancreatic tissue as a result of enhanced autoactivation of trypsinogen or decreased autocatalytic degradation (autolysis) of trypsin. To investigate the relationship between the altered properties of mutant trypsinogens and the pathomechanism of pancreatitis, wild-type and two mutant forms of recombinant human cationic trypsinogen were produced and autoactivation of trypsinogens and autolysis of trypsins were studied. The results indicate that trypsin stabilization (i.e. decreased autolysis) caused by the Arg117-->His mutation may contribute to the development of pancreatitis, however, the Asn21-->Ile mutation has no such effect. In contrast, enhanced autoactivation of mutant trypsinogens may contribute to the pathogenesis of both forms of hereditary pancreatitis. This notion is strongly supported by the clear correlation between the autoactivation rates of mutant trypsinogens and the severity of clinical symptoms.

Leptin inhibits cortisol and corticosterone secretion in pathologic human adrenocortical cells

Regulation of adrenal corticosteroid secretion by leptin may involve interactions at multiple levels of the hypothalamic-pituitary-adrenal axis. To investigate the possible direct effects of leptin on corticosteroid secretion of human adrenocortical adenomas, cells from adrenocortical adenomas causing primary aldosteronism (n = 1) and Cushing's syndrome (n = 1), as well as cells from nonhyperfunctioning adrenocortical adenomas (n = 5) were isolated and incubated for 2 h with human recombinant leptin (1-1000 ng/ml) in the presence and absence of adrenocorticotrop hormone (ACTH), then cortisol, corticosterone and aldosterone concentrations in incubating media were determined using radioimmunoassays. It was found that leptin effectively and dose-dependently inhibited basal and ACTH-stimulated cortisol and corticosterone secretion in the three types of human adrenocortical adenoma cells. The inhibiting effect of basal corticosterone secretion was detectable in the presence of leptin concentration as low as 1 ng/ml, with decreases of corticosterone secretion to 34+/-4%, 57+/-11% and 79+/-9% in Cushing's syndrome, primary aldosteronism, and nonhyperfunctioning adrenocortical adenoma cells, respectively. The inhibition of basal cortisol secretion in the presence of low concentration of leptin was less prominent, but 10 ng/ml leptin significantly diminished basal cortisol secretion to 81+/-9% in adrenocortical adenoma cells from Cushing's syndrome, to 68+/-6% in adenoma cells from primary aldosteronism, and to 83+/-8% in cells from nonhyperfunctioning adenomas. The inhibition of ACTH-stimulated cortisol and corticosterone secretion by leptin was similar to those found in cells without ACTH stimulation. By contrast, leptin even at 1000 ng/ml concentration exerted no clear effect on basal and ACTH-stimulated aldosterone secretion in cells from primary aldosteronism and in those nonhyperfunctioning adenoma cells in which aldosterone secretion was detectable. These results indicate that leptin is a potent inhibitor of cortisol and corticosterone secretion in human adenomatous adrenocortical cells. The inhibition of these corticosteroids by leptin may represent a potentially important interaction that exists between leptin and the hypothalamic-pituitary-adrenal axis.

[Celiac disease today: review of the growing knowledge]

Coeliac disease is the most common disorder with malabsorption of the small intestine, caused by the gluten fraction of cereals in genetically predisposed individuals. T-cell mediated autoimmune processes are initiated by gluten exposure, leading to both intestinal and extraintestinal manifestations, therefore coeliac disease is nowadays considered to be a systemic disorder. More and more diseases are proved to be associated with coeliac disease, in these conditions screening is strongly recommended. The studying of the recently explored autoantibodies against tissue transglutaminase brought us further in the understanding of the pathophysiology of coeliac disease. The spreading of reliable serologic methods modified our knowledge on the clinical picture and prevalence of the disease. In case of long-term dietary abuse the most common complications are decreased bone mineral density and development of lymphomas. Sustained glutenfree diet results in clinical and histological restitution, affects the course of associating diseases beneficially and decreases the risk for malignancies.

Gain-of-function mutations associated with hereditary pancreatitis enhance autoactivation of human cationic trypsinogen

Hereditary pancreatitis (HP), an autosomal dominant disorder, has been associated with mutations in the cationic trypsinogen gene. Here we demonstrate that the two most frequent HP mutations, Arg117 --> His and Asn21 --> Ile, significantly enhance autoactivation of human cationic trypsinogen in vitro, in a manner that correlates with the severity of clinical symptoms in HP. In addition, mutation Arg117 --> His inhibits autocatalytic inactivation of trypsin, while mutation Asn21 --> Ile has no such effect. The findings strongly argue that increased trypsinogen activation in the pancreas is the common initiating step in both forms of HP, whereas trypsin stabilization might also contribute to HP associated with the Arg117 --> His mutation.

Regulation of nitric oxide synthase activity by tetrahydrobiopterin in human placentae from normal and pre-eclamptic pregnancies

The possible regulatory role of tetrahydrobiopterin (BH(4)) in Type III nitric oxide synthase (NOS III) activity of human placentae from first trimester, term and pre-eclamptic pregnancies was investigated. In homogenates of first-trimester or term placentae, BH(4)stimulated NOS III activity up to 2.5-fold in a concentration dependent manner from 20 n m to 1 microm BH(4), and half-maximal stimulation (EC(50)) was observed at 100-110 n m. No significant further stimulation was detectable over an extended concentration range from 1 microm to 50 microm BH(4). NOS III present in microsomal and gel-filtered cytosol fractions exhibited similar BH(4)-activation patterns, with an identical EC(50)value of 50 n m. Remarkably, tissue concentrations of BH(4)showed a marked decrease in term placentae (57+/-23 n m, mean+/-s.d., n=26) relative to first-trimester placentae (189+/-79 n m, mean+/-s.d., n=17), suggesting that alterations in cellular BH(4)concentrations may play a more significant role in the regulation of NOS III activity in late pregnancy. Placental homogenates from 10 pre-eclamptic pregnancies exhibited two distinct types of response to BH(4). In seven placental homogenates, addition of physiological concentrations of BH(4)(20 n m to 1 microm) elicited no increase whatsoever in basal NOS III activity, and only high BH(4)concentrations (50 microm) caused notable stimulation (BH(4)resistant group). In contrast, in three of 10 placental homogenates both physiological and 50 microm BH(4)concentrations stimulated NOS III to levels similar to that of normal placentae (BH(4)responsive group). There were no appreciable differences in the clinical presentation of pre-eclampsia between the two groups. Importantly, BH(4)concentrations in pre-eclamptic placentae were comparable with those of normal, control placentae. Taken together, the observations suggest that BH(4)controls NOS III activity in the human placenta, and a defect in BH(4)regulation of NOS III may contribute to the development of pre-eclampsia. A model implicating the malfunction of placental NOS III rather than its actual tissue level in the pathogenesis of pre-eclampsia is discussed.

[Effects of growth hormone replacement therapy in adults with severe growth hormone deficiency]

The aim of the study was to analyse the effects of GH replacement therapy (1 year duration) on body composition, carbohydrate metabolism, thyroid hormone metabolism and bone mineral density in 8 adults with growth hormone deficiency (5 women, 3 men; mean age 40 years). Mean maintenance dose of GH was 1.5 IU/day-1.76 IU/day for women and 1.07 IU/day for men, respectively--determined according to individual patient requirements. Serum insulin-like growth factor-I standard deviation score increased from -5.4 to 0.0 (p < 0.001). There was a significant negative relationship between serum insulin-like growth factor-I standard deviation score at the start of therapy and the increase in this score (r = -0.85; p < 0.05). The waist:hip ratio decreased after 12 months by 0.039 (p < 0.05). The glycosylated hemoglobin increased (4.43 +/- 0.56% vs. 5.86 +/- 0.27; p < 0.05), and a negative correlation of the baseline glycosylated hemoglobin to the glycosylated hemoglobin increase was found (r = -0.88; p < 0.01). Both the free triiodothyronine and free triiodothyronine:free thyroxine ratio increased (3.09 +/- 0.22 vs. 4.17 +/- 0.40; p < 0.05, and 0.234 +/- 0.02 vs. 0.324 +/- 0.04; p < 0.01), and a positive relationship was observed between this ratio at the start of therapy and the increase in the ratio (r = 0.76, p < 0.05). The bone mineral density of lumbar spine and femoral neck expressed as z-score increased (-1.18 +/- 0.56 vs. -0.75 +/- 0.48; p < 0.01 and -0.06 +/- 0.60 vs. 0.43 +/- 0.43; p < 0.05), while the bone mineral density of forearm was unchanged.

CONCLUSIONS

Growth hormone replacement leads to a decrease in visceral fat, modulates the thyroid hormone levels by increasing peripheral conversion of thyroxine to triiodothyronine and probably is a physiological regulator of peripheral thyroxine metabolism, slightly deteriorates the carbohydrate metabolism, and results in an increase of bone mineral density of lumbar spine and femoral neck.

High-affinity Ca(2+) binding inhibits autoactivation of rat trypsinogen

The recent discovery that mutation Asn21 --> Ile in the human cationic trypsinogen (Tg) is associated with hereditary pancreatitis has brought into focus the functional role of amino acid 21 in mammalian Tgs. In the present paper, the effect of mutations Thr21 --> Asn and Thr21 --> Ile on the Ca(2+) dependence of zymogen activation was investigated, using the autolysis-resistant rat Tg mutant Arg117 --> His. In the absence of Ca(2+), rat Tg exhibited low but significant basal autoactivation, which was inhibited by micromolar concentrations of Ca(2+) (IC(50) 2.6 microM). Interestingly, basal autoactivation was diminished in both mutants, and no further inhibition by micromolar Ca(2+) was detectable. Millimolar Ca(2+) concentrations markedly and comparably stimulated autoactivation of wild-type and mutant zymogens (EC(50) 1.7-2.4 mM). The results indicate that rat Tg is subject to dual regulation by Ca(2+), allowing zymogen stabilization in a low-Ca(2+) environment and efficient activation in a high-Ca(2+) milieu.

Circulating plasma endothelin-1, plasma lipids and complications in Type 1 diabetes mellitus

The damage of endothelial integrity is an important step in the atherogenic process. To evaluate the role of circulating endothelin-1 (ET-1) in Type 1 diabetes mellitus (T1DM), plasma ET-1 levels were evaluated in T1DM patients either with (n=9) or without hyperlipidaemia (n=11), or with (n=9) and without (n=11) late diabetic complications, in non-diabetic hyperlipidaemic patients (n=17) and in healthy volunteers. Groups were matched for age, sex and body mass index.

RESULTS

Serum total cholesterol and apolipoprotein B were significantly higher in the diabetic group (p<0.05). Plasma ET-1 level was similar in controls and in non-diabetic hyperlipidaemic subjects (5.77+/-1.74 ng/l vs 4.97+/-1.58 ng/l); however, diabetic hyperlipidaemic patients had a significantly higher plasma ET-1 concentration compared to control subjects (6.67+/-2.44 ng/l vs 4.97+/-1.58 ng/l, p<0.05). Diabetic patients with vascular complications had a significantly higher plasma ET-1 concentration than found in diabetic patients without complications (6.99+/-2.17 ng/l vs 4.74+/-1.27 ng/l, p<0.01) and in controls (6.99+/-2.17 ng/l vs 4.97+/ 1.58 ng/l, p<0.01). Patients with diabetic complications also had a significantly higher apolipoprotein B level compared to healthy controls (0.94+/-0.37 g/l vs 0.66+/-0.12 g/l, p<0.005).

CONCLUSION

The susceptibility of T1DM patients to the development of atherosclerosis might be attributed to the relationship between elevated lipid levels and ET-1.

Comparative analysis of plasma 17-hydroxyprogesterone and cortisol responses to ACTH in patients with various adrenal tumors before and after unilateral adrenalectomy

Patients with non-hyperfunctioning adrenal adenomas often have an increased plasma 17-hydroxyprogesterone response to ACTH stimulation. The effects of adrenal surgery on this abnormality have rarely been investigated. One hundred and sixty-one patients with unilateral adrenal tumors (non-hyperfunctioning adenomas, 78; cortisol-producing adenomas, 8; aldosterone-producing adenomas, 37; adrenal cysts, 12; pheochromocytomas, 26) were studied. Patients before and after adrenal surgery as well as 60 healthy subjects underwent an ACTH stimulation test using 2 mg synthetic ACTH(1-24) (Cortrosyn Depot, Organon). Basal and ACTH-stimulated plasma 17-hydroxyprogesterone and cortisol concentrations are reported. Before adrenal surgery, the basal plasma 17-hydroxyprogesterone concentrations were normal in patients with all types of tumors. However, the ACTH-stimulated plasma 17-hydroxyprogesterone levels were abnormally increased in 53% and 31% of patients with non-hyperfunctioning adenomas and aldosterone-producing adenomas, respectively. In addition, a few patients with adrenal cysts and pheochromocytomas also showed an increased ACTH-stimulated 17-hydroxyprogesterone response. After unilateral adrenalectomy, this hormonal abnormality disappeared in most, although not all patients with adrenal tumors. In patients with non-hyperfunctioning adrenal tumors, ACTH-stimulated plasma 17-hydroxyprogesterone and cortisol concentrations significantly correlated with the size of the tumors. These results firmly indicate that the tumoral mass itself may be responsible for the increased plasma 17-hydroxyprogesterone and cortisol responses after ACTH stimulation in patients with non-hyperfunctioning and hyperfunctioning adrenal adenomas.

Are there systemic changes in the arterial biomechanics of intracranial aneurysm patients?

Current theories on the development of intracranial aneurysm suggest that there is a general weakness of vascular connective tissue. Potential systemic alterations in arterial wall biomechanics were tested in the present study. A three-dimensional in vitro stress-strain analysis was made in the 0-200-0 mmHg pressure range on cylindrical segments excised from the anterior cerebral artery, the radial artery and from the arteria dorsalis pedis of aneurysm patients and of control cadavers. In the anterior cerebral artery from aneurysm patients (intracranial artery segments directly not affected by the aneurysm or by the subarachnoid bleeding), we found the wall thickness to be larger (0.1480+/-.019 versus 0.091+/-0.004 mm), the radius/wall thickness ratio smaller (9.7+/-1.4 versus 14.1+/-1.2), and the tangential wall stress lower [(0.122+/-0.019)x10(6) versus (0.181+/-0.016)x10(6) N/m2 at 100 mmHg] than in control subjects. Reduced radius was found in the extremity arteries studied. Elastic parameters, as incremental distensibility and elastic modulus, were remarkable similar. Our study demonstrates changes in the geometry of walls of arteries not directly affected by aneurysm formation, and it thus confirms systemic vascular pathology in this disease. At the same time, these data show that the molecular and morphological defects of arterial connective tissue formation generally thought to induce intracranial aneurysms will probably not affect the components responsible for the passive elastic properties of the vascular wall.

Enhanced accumulation of pericardial fluid ferritin in patients with coronary artery disease

BACKGROUND

Ferritin is a storage protein for iron that can either represent a source of iron or perform a cytoprotective action as an iron sequestrant.

OBJECTIVE

To compare the concentrations of ferritin in pericardial fluid of patients with valvular heart disease, serving as controls, and in patients with coronary artery disease.

DESIGN

We studied a total of 59 consecutive male patients undergoing elective heart valve replacement (group 1: n = 22, mean +/- SD age 55 +/- 11 years) or elective coronary artery bypass grafting (group 2: n = 37, mean +/- SD age 59 +/- 9 years).

METHODS

Iron status indicators, total protein and albumin concentrations, and lactate dehydrogenase activities were determined in pericardial fluid and serum samples obtained from patients during surgery.

RESULTS

Pericardial fluid concentrations of ferritin in both patient populations were significantly (P < 0.001) greater than the concentrations in sera: group 1, 375 (107-2030) micrograms/l compared with 146.5 (21-407) micrograms/l; group 2, 1115 (226-2500) micrograms/l compared with 152.0 (16-398) micrograms/l (median (range)), respectively. Moreover, pericardial fluid ferritin concentration was significantly (P < 0.01) greater in patients undergoing coronary artery bypass grafting than in those undergoing heart valve replacement, whereas serum ferritin concentrations did not differ between the two patient populations.

CONCLUSIONS

As pericardial fluid reflects the composition of the myocardial interstitium, we suggest that ferritin released can serve as a potential source of iron in the cardiac interstitium that may promote the generation of oxygen free radicals. Conversely, we presume that induction of ferritin synthesis, representing an important mechanism by which tissue adapts to hypoxic damage, can afford myocardial cytoprotection.

[Glucocorticoid-induced osteoporosis]

Chronic glucocorticoid treatment is the most frequent cause of secondary osteoporosis. The direct inhibitory effect of glucocorticoids on osteoblasts results in decreased bone formation. Increased osteoclastic bone resorption due to low concentrations of gonadal steroid hormones and glucocorticoid-induced direct suppression of intestinal calcium absorption also contribute to the decrease of bone mass in these patients. Bone loss is rapid, particularly in the first months of glucocorticoid therapy. Bone mineral density of the lumbar spine and proximal femur should be measured in patients who are starting chronic therapy with glucocorticoids. Although glucocorticoid-induced osteoporosis is a severe and nowadays partially preventable disorder, osteoporosis prophylaxis is only rarely prescribed to these patients. Recent randomized, controlled trials proved the therapeutic effects of hormone replacement therapy, as well as of bisphosphonates and active vitamin D analogs in primary and secondary prevention of glucocorticoid-induced osteoporosis.

[Effective demeclocycline therapy in a patient with over-secretion of antidiuretic hormone following head trauma]

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a common cause of hyponatremia. In this study a case of SIADH caused by head trauma is reported, in which severe hyponatraemia, escorted by life-threatening neurological symptoms was observed that could only be managed by parenteral sodium chloride infusions. Severe hyponatraemia was accompanied by elevated urinary sodium excretion, a characteristic sign of SIADH. After introducing the therapy with demeclocycline, a tetracycline type antibiotic that inhibits the renal action of antidiuretic hormone, serum sodium levels began to rise gradually, and the urinary sodium excretion slowly decreased. These observations show the effectiveness of demeclocycline in the treatment of SIADH.

Trypsinogen stabilization by mutation Arg117-->His: a unifying pathomechanism for hereditary pancreatitis?

Mutations Arg117-->His and Asn21-->Ile of the human cationic trypsinogen have been recently identified in patients affected by hereditary pancreatitis (HP). The Arg117-->His substitution is believed to cause pancreatitis by eliminating an essential autolytic cleavage site in trypsin, thereby rendering the protease resistant to inactivation through autolysis. Here we demonstrate that the Arg117-->His mutation also significantly inhibits autocatalytic trypsinogen breakdown under Ca(2+)-free conditions and stabilizes the zymogen form of rat trypsin. Taken together with recent findings demonstrating that the Asn21-->Ile mutation stabilizes rat trypsinogen against autoactivation and consequent autocatalytic degradation, the observations suggest a unifying molecular pathomechanism for HP in which zymogen stabilization plays a central role.

Effects on substrate profile by mutational substitutions at positions 164 and 179 of the class A TEM(pUC19) beta-lactamase from Escherichia coli

We investigated the effects of mutations at positions 164 and 179 of the TEM(pUC19) beta-lactamase on turnover of substrates. The direct consequence of some mutations at these sites is that clinically important expanded-spectrum beta-lactams, such as third-generation cephalosporins, which are normally exceedingly poor substrates for class A beta-lactamases, bind the active site of these mutant enzymes more favorably. We employed site-saturation mutagenesis at both positions 164 and 179 to identify mutant variants of the parental enzyme that conferred resistance to expanded-spectrum beta-lactams by their enhanced ability to turn over these antibiotic substrates. Four of these mutant variants, Arg(164) --> Asn, Arg(164) --> Ser, Asp(179) --> Asn, and Asp(179) --> Gly, were purified and the details of their catalytic properties were examined in a series of biochemical and kinetic experiments. The effects on the kinetic parameters were such that either activity with the expanded-spectrum beta-lactams remained unchanged or, in some cases, the activity was enhanced. The affinity of the enzyme for these poorer substrates (as defined by the dissociation constant, K(s)) invariably increased. Computation of the microscopic rate constants (k(2) and k(3)) for turnover of these poorer substrates indicated either that the rate-limiting step in turnover was the deacylation step (governed by k(3)) or that neither the acylation nor deacylation became the sole rate-limiting step. In a few instances, the rate constants for both the acylation (k(2)) and deacylation (k(3)) of the extended-spectrum beta-lactamase were enhanced. These results were investigated further by molecular modeling experiments, using the crystal structure of the TEM(pUC19) beta-lactamase. Our results indicated that severe steric interactions between the large 7beta functionalities of the expanded-spectrum beta-lactams and the Omega-loop secondary structural element near the active site were at the root of the low affinity by the enzyme for these substrates. These conclusions were consistent with the proposal that the aforementioned mutations would enlarge the active site, and hence improve affinity.

No teratogenic effect after clotrimazole therapy during pregnancy

We evaluated the potential teratogenic effects of vaginal and/or topical administration of clotrimazole in the large population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1992). The dataset included 18,515 case pregnancies and 32,804 control pregnancies; 7.1% of case and 7.7% of control women used clotrimazole during pregnancy. Clotrimazole use was not clearly associated with an increase in the total (fetal + birth) prevalence of any congenital abnormality group. There was, however, a suggestion that clotrimazole use was associated with a decrease in the prevalence of undescended testis (prevalence odds ratio = 0.72; 95% confidence interval = 0.54-0.95).

[Ret-protooncogene mutation, verified by molecular genetic methods, in a Hungarian MEN Type 2a family]

Multiple endocrine neoplasia Type 2 (MEN2) is a hereditary tumour syndrome characterized by the association of medullary thyroid cancer, phaeochromocytoma and hyperparathyroidism. It is inherited as an autosomal dominant trait. During the past few years the cloning of the gene responsible for the syndrome, the ret protooncogene, made the molecular genetic diagnosis of the disease possible. In this study we demonstrate the results of the MEN2 mutation analysis performed in three members of a Hungarian MEN2A family. The mutation analysis was carried out according to the method of Dr. W. Hoppner's Laboratory (Hamburg) that is the main centre for MEN2 genetic diagnosis in Germany. Two Members of the family are affected, one suffered from both medullary thyroid cancer and phaeochromocytoma, the other (the first patient's daughter) had only medullary thyroid cancer. We found a ret exon 11 codon 634 mutation, that resulted in the change of TGC to TAC, a cysteine-tyrosine amino acid exchange. We found no mutation in the youngest member of the family. This result is of great clinical significance, because the carrier status of this individual can thus be excluded and, therefore, there is no need for prophylactic thyroidectomy and further clinical screening tests. As molecular genetic diagnosis of MEN2 becomes possible, the uncertain clinical examinations used for MEN2 diagnosis seems to be less important.

Hyperreactio luteinalis in a normal singleton pregnancy. A case report

BACKGROUND

Hyperreactio luteinalis rarely occurs in normal singleton pregnancy. About 50 such cases have been published. This case is noteworthy because it resulted in extremely enlarged ovaries and was accompanied by a hyperandrogenic state and high level of human chorionic gonadotropin.

CASE

A gravida was referred to our department because of large, bilateral, cystic ovaries diagnosed by ultrasonography in the 28th week of gestation. Markedly elevated levels of androgens and human chorionic gonadotropin were noted. During the following six weeks the ovarian masses enlarged, and the hyperandrogenic state worsened. Cesarean section and, because of a bleeding right adnexectomy, left ovarian resection were performed. Histology confirmed the presumed diagnosis of hyperreactio luteinalis. The placenta was unremarkable. Seventeen weeks after surgery the hormone levels were normal.

CONCLUSION

Our case suggests the possibility that in certain cases of hyperreactio luteinalis, an idiopathic elevation of human chorionic gonadotropin, can occur even in normal singleton pregnancies. Furthermore, it calls attention to the necessity of ultrasonographic demonstration of ovaries even during late pregnancy.