Direct laparoscopic venous sampling to diagnose a small Sertoli-Leydig tumor

BACKGROUND

Sertoli-Leydig cell tumors (SLCT) constitute only 0.5% of all primary ovarian neoplasms. We report a unique diagnostic method (selective laparoscopic venous sampling) and a rare case of a contralateral second primary tumor.

CASE

A 14-year-old female presented with hyperandrogenic complaints and an increased serum testosterone. Ovarian origin was confirmed by direct laparoscopic ovarian blood sampling. A right salpingo-oophorectomy was performed. The pathological diagnosis was SLCT of intermediate differentiation. Three years later, the patient presented again with an increased serum testosterone. A solid tumor in the left ovary was excised. The pathology was SLCT of intermediate differentiation. The patient remains disease-free.

CONCLUSIONS

Direct laparoscopic venous sampling is used to diagnose a small SLCT in a teenage patient.

Analysis of the post-translational processing of chromogranin A in rat neuroendocrine tissue employing an N-terminal site-specific antiserum

Chromogranin A (CgA) is a complex prohormone expressed as a constituent of the regulated secretory pathway of numerous neuroendocrine cells. Recent investigations have demonstrated that CgA is selectively cleaved to generate distinct peptides in different neuroendocrine tissues. This investigation employed a site-specific antiserum that detects residues 98-106 rat CgA to examine the amino-terminal processing of CgA to generate beta-granin and related peptides in rat neuroendocrine tissues. Immunohistochemistry revealed moderate to intense beta-granin-like immunostaining in cells scattered throughout the anterior pituitary, thyroid, in the islets of Langerhans and in the mucosa of the gastrointestinal tract. Variable intensities of immunostaining were observed in distinct clusters of chromaffin cells. Quantitatively, the highest concentration of beta-granin-like immunoreactivity was detected in pituitary extracts. Significantly lower concentrations were detected in adrenal and thyroid glands, brain, ventral and dorsal pancreatic lobes and gastrointestinal tissue extracts. Chromatography resolved three distinct beta-granin-like immunoreactants; a large CgA-like form, an intermediate molecular form presumably corresponding to beta-granin (rat CgA1-128) and small immunoreactants that coeluted with the synthetic peptide. Two beta-granin-like immunoreactants, 21 and 22 kDa, were detected following immunoblot analysis of pituitary extracts. This study has demonstrated that chromogranin A is subject to distinct amino-terminal patterns of tissue-and cell-specific processing to generate a beta-granin-like immunoreactant which is additionally cleaved in pancreatic, fundic and colonic tissue to generate previously unidentified peptides.

Gastric corpus atrophy following eradication of Helicobacter pylori

BACKGROUND

Atrophic gastritis can develop in patients with Helicobacter pylori infection leading to a reduction in basal acid output. Whether the atrophy that develops is reversible is controversial.

OBJECTIVE

To investigate the effect of H. pylori eradication in infected subjects who had developed atrophy of the corpus mucosa.

METHOD

Ten H. pylori positive patients with corpus atrophy were identified at oesophagogastroduodenoscopy (OGD). They received eradication therapy with amoxicillin, clarithromycin and omeprazole. Repeat OGD with biopsy was performed at least 3 months later. Fasting plasma gastrin was measured at baseline and at re-endoscopy. H. pylori eradication was confirmed by 13C urea breath testing.

RESULTS

Median time to re-endoscopy was 5 months. There was improvement in corpus atrophy in 50% of patients after H. pylori eradication, and a significant reduction in plasma gastrin (P = 0.03). The index patients had a significant diminution of basal acid output compared to controls.

CONCLUSION

Corpus atrophy as defined by the Sydney System is reversible in some patients after H. pylori eradication. Improvement in atrophy is associated with a fall in fasting plasma gastrin levels. This may have implications in the prevention of gastric carcinoma.

Immunohistochemical evaluation of the post-translational processing of chromogranin A in human pituitary adenomas

Chromogranin A (CgA), pancreastatin (PST), intervening-peptide (IP) and WE-14 antisera were employed to investigate the proteolysis of CgA in 50 pituitary adenomas. All non-functioning (NF) pituitary tumours (n = 28) exhibited CgA immunoreactivity. PST, IP and WE-14 immunostaining was observed in 85%, 89% and 67%, respectively. CgA, PST and IP immunostaining were comparable in the majority of NF tumours, while less intense WE-14 immunoreactivity was detected in a subpopulation of NF tumour cells. Approximately half of the functioning pituitary tumours expressed CgA immunoreactivity. Six of nine ACTH-secreting tumours displayed CgA and IP immunostaining; four of these tumours displayed PST immunoreactivity. WE-14 immunoreactivity was detected in one corticotroph tumour. Three of six growth hormone (GH) secreting tumours displayed CgA immunostaining, two exhibited PST and IP, and one exhibited WE-14 immunoreactivity. Clusters of WE-14 immunopositive cells were detected in one GH tumour. One of seven prolactinomas exhibited weak CgA immunostaining, while weak IP and WE-14 immunostaining was detected in an additional tumour. No PST immunostaining was detected in prolactinomas. Therefore CgA is a valuable marker of NF pituitary tumours, however it is a more sporadic marker of functioning adenomas. In general, the cellular pattern and intensities of CgA, PST and IP immunoreactivity were comparable in the majority of pituitary adenomas. In contrast, WE-14 immunostaining was observed in a subpopulation of tumour cells. The pathophysiological significance of the proteolysis of CgA to generate bioactive peptides in both NF and functioning pituitary adenomas remains to be established.

Neuropeptide variability in man

BACKGROUND

Previous studies have established short-term variability in the circulating plasma levels of cardiac peptides such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Our aim was to investigate whether such variable patterns could be observed in other vasoactive peptides.

METHODS

We measured the immunoreactivity of vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), endothelin-1 (ET-1) and calcitonin gene-related peptide (CGRP) in peripheral venous plasma collected at 2-min intervals over a 20-min period from patients with chronic cardiac failure (CCF) and from control subjects. In a second study, blood samples were obtained at 2-min intervals from the pulmonary artery, femoral artery and antecubital vein from patients with normal cardiac function while right atrial pressure and heart rate were constant.

RESULTS

Peripheral blood VIP, NPY and ET-1 had peaks and troughs (levels > 2SD from the mean) in both patients and controls, with approximate intervals of 10 min. Levels of CGRP showed little variation. The overall levels [median (range); pmol L-1] of VIP [patients 27 (2.1-85.5); controls 9.8 (0-34)] and NPY [patients 20 (0-110); controls 12 (5-19)] were higher in patients (P < 0.05). Circulating plasma levels of ET-1 and CGRP were about the same in both groups [ET-1: patients 18 (2-84); controls 18 (0-48); CGRP: patients 4 (1-18.5), controls 5.5 (1-15); P = NS]. Levels of CGRP, VIP and ET-1 were similar in the pulmonary and femoral arteries, whereas systemic arterial levels of NPY were higher than in the pulmonary artery.

CONCLUSIONS

The data demonstrate marked variability in circulating levels of the neuropeptides studied. In addition, peaks and troughs were observed every 10-15 min from all three vascular beds. If these peptides are secreted in a pulsatile pattern, then interpretations of single measurements should be guarded. Furthermore, this study raises interesting questions about the physiology of hormone secretion in man.

Is the secretion of atrial natriuretic peptide in man under neural control?

AIMS

Previous work has described short-term variation in the circulating plasma level of atrial natriuretic peptide (ANP), but the mechanism remains unknown. Our aim was to investigate the role of cardiac innervation in this variability.

METHODS AND RESULTS

Blood samples were obtained from the right atrium via a pulmonary artery flotation catheter every 2 min over a 90 min period. Seven patients who underwent cardiac transplantation by the standard biatrial technique (partial innervation) and ten patients who underwent transplantation by the bicaval technique (total denervation) were studied. ANP levels were measured by radioimmunoassay. The median ANP levels were somewhat higher in the biatrial group compared to the bicaval group [470 (150-1095) vs. 216 (100-605) pg. ml(-1); median (range); P = ns], and both were much higher than normal levels in the pulmonary artery (40 (24, 56) pg ml(-1); median and interquartile range). In both transplant groups circulating plasma ANP levels showed considerable variability. The median number of 'peaks' and 'troughs', as counted by visual inspection, were not significantly different between the two groups. Computer analysis identified 12-16 and 6-15 'pulses' in the biatrial and bicaval group, respectively. Further analysis revealed that pulse amplitude, height and area were significantly higher in the biatrial compared to the bicaval group.

CONCLUSION

It would appear that variability of circulating plasma levels of ANP is preserved despite complete or partial cardiac denervation, and so a neural mechanism does not appear to account for such variation.

Calcitonin gene-related peptide, neuropeptide Y and atrial natriuretic peptide distribution in guinea pig heart from paraffin wax-embedded and formalin-cryoprotected tissues

In this study, the distributions of calcitonin gene-related peptide, neuropeptide Y, and alpha-atrial natriuretic peptide 1-28 immunoreactivity, were investigated within different regions of the guinea pig heart by utilising two different methods of tissue fixation for the immunocytochemistry. The results were compared with data obtained through radioimmunoassays. We observed similar concentrations and distributions of alpha-atrial natriuretic peptide in the right atrium, with results of radioimmunoassay and immunocytochemistry, but there were no myocytes containing alpha-atrial natriuretic peptide in the left atrium or ventricles with immunocytochemistry as opposed to radioimmunoassay. The immunoreaction obtained for neuropeptide Y was more intense in the right ventricle than left. Calcitonin gene-related peptide nerve fibres were about twice as abundant in the left atrium than in the right.

The rise in circulating gastrin with age is due to increases in gastric autoimmunity and Helicobacter pylori infection

To assess the effect of increasing age on circulating gastrin, we surveyed serum gastrin, Helicobactor pylori seroantibody status and gastric autoimmunity in 366 hospitalized patients aged 15-90 years. Data were subjected to multivariate analysis, using logarithmic transformation to normalize the distribution of gastrin concentrations (presented as geometric means and 95% CIs). The frequency of H. pylori-positive antibody status increased with age from 28% in the second decade to > 70% beyond the fourth decade. Fasting gastrin concentrations rose significantly from 44 ng/l (41-48) in the second decade to 95 ng/l (67-131) by the eighth decade (p = 0.001) in the total group. Twenty-seven patients (6.8% of the total) tested positive for gastric auto-antibodies: 2% of patients in the second decade, rising to 15.9% in the eighth decade. These patients formed a distinct group with respect to circulating gastrin concentrations. Excluding these 27, fasting gastrin concentrations still rose significantly, from 44 ng/l (41-48) in the second decade, to 67 ng/l (50-89) in the eighth decade (p = 0.003) in the remaining 341 patients. Fasting gastrin concentrations were significantly higher in patients who were H. pylori-seropositive (59 ng/l, 54-64 vs. sero-negative 41 ng/l, 37-46) (p = 0.002), and there was no increase in circulating gastrin concentrations with increasing age in either the H. pylori-positive or the H. pylori-negative group. The increase in circulating fasting gastrin observed with increasing age is due to an increased incidence of gastric antibodies associated with auto-immune atrophic gastritis, and an increased incidence of H. pylori infection.

Euglycaemic hyperinsulinaemia does not affect gastric emptying in type I and type II diabetes mellitus

Hyperglycaemia slows gastric emptying in both normal subjects and patients with diabetes mellitus. The mechanisms mediating this effect, particularly the potential role of insulin, are uncertain. Hyperinsulinaemia has been reported to slow gastric emptying in normal subjects during euglycaemia. The purpose of this study was to evaluate the effect of euglycaemic hyperinsulinaemia on gastric emptying in Type I (insulin-dependent) and Type II (noninsulin-dependent) diabetes mellitus. In six patients with uncomplicated Type I and eight patients with uncomplicated Type II diabetes mellitus, measurements of gastric emptying were done on 2 separate days. No patients had gastrointestinal symptoms or cardiovascular autonomic neuropathy. The insulin infusion rate was 40 mU x m(-2) x min(-1) on one day and 80 mU x m(-2) x min(-1) on the other. Gastric emptying and intragastric meal distribution were measured using a scintigraphic technique for 3 h after ingestion of a mixed solid/liquid meal and results compared with a range established in normal volunteers. In both Type I and Type II patients the serum insulin concentration had no effect on gastric emptying or intragastric meal distribution of solids or liquids. When gastric emptying during insulin infusion rates of 40 mU x m(-2) x min(-1) and 80 mU x m(-2) x min(-1) were compared the solid T50 was 137.8+/-24.6 min vs. 128.7+/-24.3 min and liquid T50 was 36.7+/-19.4 min vs. 40.4+/-15.7 min in the Type I patients; the solid T50 was 94.9+/-19.1 vs. 86.1+/-10.7 min and liquid T50 was 21.8+/-6.9 min vs. 21.8+/-5.9 min in the Type II patients. We conclude that hyperinsulinaemia during euglycaemia has no notable effect on gastric emptying in patients with uncomplicated Type I and Type II diabetes; any effect of insulin on gastric emptying in patients with diabetes is likely to be minimal.

Immunostaining for vasostatin I distinguishes between ileal and lung carcinoids

Although chromogranin A (CgA) is a recognized marker of neuroendocrine tumours, little is known about the distribution of the CgA-derived peptides, vasostatin (VST) I or II, in these tumours. Rabbit polyclonal antiserum was raised to a fragment of VST I and used to immunostain sections (5 microns) of wax-embedded tumour tissue. Immunoreactivity (IR) was detected using swine anti-rabbit fluorescein secondary antibody and sections were viewed by fluorescence microscopy. Of 24 tumours from patients with lung carcinoids, one was weakly positive, while 23 of 26 ileal carcinoid tumours were immunoreactive. Metastatic deposits from patients with ileal carcinoids also tended to be immunoreactive (9/10). The difference in IR between lung and ileal carcinoid primary tumours did not appear to be related to the metastatic potential, since appendiceal tumours, which seldom metastasize, also tended to be immunoreactive (4/6) for VST I. The strongest IR was recorded in two patients with flushing as a result of ileal carcinoids; five other 'flushers' with ileal carcinoids were also immunopositive for VST I-like IR. By contrast, patients with flushing as a result of lung carcinoids were immunonegative for VST. In conclusion, VST I-like IR may assist in the identification of a secondary deposit from an unknown primary site.

Autoantibodies to gastrin in patients with pernicious anaemia--a novel antibody

Autoantibodies arise when there is a breakdown in immunological tolerance. Autoantibodies to parietal cells and intrinsic factor are found in autoimmune atrophic gastritis (AAG) and are associated with elevated plasma gastrin. Endogenous gastrin autoantibodies have not been described to date. The aim of this study was to investigate the occurrence of autoantibodies to gastrin. Plasma from 50,000 patients, including more than 2000 with AAG, was tested. Gastrin was measured by radioimmunoassay (RIA) in whole plasma and the presence of autoantibody determined by using a control which omitted assay antibody. The quantity and affinity of gastrin autoantibodies was assessed. Three patients had autoantibodies to gastrin. All three had AAG and pernicious anaemia (PA). The antibodies were of low titre and relatively high affinity. Free circulating plasma gastrin levels were within the normal range, but total gastrin levels were elevated. This is the first description of autoantibodies to endogenous gastrin. The incidence of antibodies to gastrin is low, they are found in association with PA, and they may lead to falsely low measurements of plasma gastrin.

Gastrinomas and the change in their presentation and management in Northern Ireland, UK, from 1970 to 1996

Thirty-five new cases of gastrinomas were diagnosed in N. Ireland between 1970 and 1996. Over this period, patient care has improved, with advances in imaging techniques and therapeutic regimens. Patients are now no longer presenting in the classical way with severe ulcer diathesis. Diarrhoea is often a major feature, occurring in 46% of patients. Thirty-one percent of patients presented with mixed amine precursor, uptake and decarboxylation (APUD) tumours. Survival has improved, most likely as a result of better detection of tumours, as well as treatment that is aimed at resection and removal of the gastrinoma. The advent of proton pump inhibitors has ensured symptom control in those for whom total tumour removal is impossible. Owing to improved survival, metastatic complications are often associated with patient mortality.

Bcl-2 and c-Myc, but not bax and p53, are expressed during human medullary thyroid tumorigenesis

Medullary thyroid carcinoma (MTC) is a tumor of parafollicular cells of the thyroid gland. It has served as a useful experimental model for the study of tumor proliferation and differentiation. Although recent studies have identified the gene involved in familial forms of MTC, little is known about the molecular pathogenesis of the sporadic variants of this tumor. It has become increasingly clear that deregulation of programmed cell death is a critical component in multistep tumorigenesis. The present investigation was undertaken to determine whether similar molecular events occur in human MTC. Eighteen MTCs from 18 patients (including 12 sporadic and six familial cases and one metastatic lymph gland) and a MTC cell line (TT cells) were used in this study for detecting the expression of apoptosis-regulatory genes bcl-2, bax, c-myc, and p53. Immunohistochemical results showed that all MTC tumor samples displayed Bcl-2 and c-Myc immunoreactivity, whereas only 4 and 2 tumors showed a minority of cells positive for Bax and p53, respectively. Western and Northern blotting showed high levels of 26-kd Bcl-2 protein and bcl-2 transcript. The co-expression of Bcl-2 and c-Myc was also detected in the TT cells by indirect fluorescence immunohistochemistry and Western blotting. Moreover, Bcl-2 immunoreactivity was also found in C-cell hyperplasia from familial patients indicating that expression of this oncogene may represent an early event in the pathogenesis of MTC. The present study suggests that deregulation of programmed cell death may be a critical component in multistep tumorigenesis of MTC and that the frequent expression of the Bcl-2 oncoprotein in these tumors may contribute to their pathogenesis. The genetic complementation of simultaneously deregulated bcl-2 and c-myc may be implicated in the multistep tumorigenesis of human MTC.

Neurokinin A is the predominant tachykinin in human bronchoalveolar lavage fluid in normal and asthmatic subjects

BACKGROUND

Multiple sensory neuropeptides are present in human airways and may contribute to diseases such as asthma. This study quantified and characterised substance P (SP), neurokinin A (NKA), and calcitonin gene related peptide (CGRP) immunoreactivity in bronchoalveolar lavage fluid in asthmatic and normal subjects.

METHODS

Using specific radioimmunoassay (RIA), SP, NKA and CGRP were measured in bronchoalveolar lavage fluid from asthmatic subjects (n = 5), normal subjects (n = 5), atopic non-asthmatic subjects (n = 6), and asthmatic subjects four hours after allergen challenge (n = 12). Peptide immunoreactivity was characterised using high performance liquid chromatography (HPLC) and RIA.

RESULTS

No SP or CGRP immunoreactivity was detected in any of the fractions from samples after extraction, HPLC, and RIA. Non-specific binding resulted in spurious SP immunoreactivity being detected in bronchoalveolar lavage fluid when no extraction process was employed. NKA was detected in significant amounts in asthmatic (median 550, range 425-625 pg/ml) and normal subjects (median 725, range 350-1425 pg/ml). The level of NKA was significantly higher in the asthmatic subjects after allergen challenge (median 750, range 350-1250 pg/ml) than in unchallenged asthmatic subjects (median 600, range 425-600 pg/ml, p < 0.01).

CONCLUSIONS

Extraction and characterisation of peptides from bronchoalveolar lavage fluid must be performed to ensure that the measured immunoreactivity represents target peptide. NKA is present in bronchoalveolar lavage fluid in high concentrations and is the predominant tachykinin. The concentrations of NKA are similar in normal subjects and subjects with mild asthma.

Effect of euglycaemic hyperinsulinaemia on gastric emptying and gastrointestinal hormone responses in normal subjects

Several studies have shown that hyperglycaemia slows gastric emptying in normal subjects and patients with diabetes mellitus but whether hyperinsulinaemia per se has an effect remains debatable. In the present study we have assessed the effect of hyperinsulinaemia on gastric emptying of a solid and liquid meal in normal subjects. Ten men were studied three times in random order. After an overnight fast, subjects were infused with 0.9% NaCl on two occasions and on the third with insulin, at 40 mU x m(-2) x min(-1) with 20% glucose simultaneously to maintain euglycaemia. Steady-state glucose infusion rate was ensured before the subjects ate a standard meal of a pancake labelled with 99mTc and milkshake labelled with (111)In-DTPA. Gamma-scintigraphic images were then obtained every 20 min for the next 3 h. There were no significant differences between the mean half-emptying times (T50) of the solid and liquid during the two saline infusions (129.6 +/- 28.5 vs 128.4 +/- 23.8 min for the solid and 25.4 +/- 7.0 vs 34.7 +/- 18.0 min for the liquid, mean +/- SD). Hyperinsulinaemia delayed both solid (mean T50 149.6 +/- 30.7, p = 0.031) and liquid emptying (mean T50 39.8 +/- 13.9, p = 0.042). There were no significant differences in the cholecystokinin and glucagon-like peptide 1 responses to the meal during either saline or insulin infusions. There was a tendency towards a greater insulin response to the meal during the hyperinsulinaemic study. Thus, hyperinsulinaemia delayed emptying of both the solid and liquid components of the meal.

Localization of neuroendocrine tumours with [111In] DTPA-octreotide scintigraphy (Octreoscan): a comparative study with CT and MR imaging

A wide variety of neuroendocrine tumours express somatostatin receptors, and can be visualized by radiolabelled somatostatin analogue scintigraphy. To investigate the value of [111In]-octreotide scintigraphy (Octreoscan), 48 patients (37 with proven carcinoid, pancreatic endocrine and medullary carcinoma of thyroid tumours, 11 with neuroendocrine syndromes multiple endocrine neoplasia (MEN-I) and Zollinger-Ellison syndrome (ZES) were examined with 111In-DTPA-D-Phe1-octreotide. Scintigrams were obtained at 24 and 48 h, and the results were compared with CT and magnetic resonance imaging (MRI). Thirty-five of 48 patients had positive [111In]-octreotide scintigraphy (23/25 (92%) carcinoids, 8/9 (89%) PETs, 4/11 (36%) MEN-I & ZES). Of the 42 lesions located by conventional imaging techniques, 37 (88%) were also identified by Octreoscan. Unexpected lesions (40 sites), not detected by CT or MR imaging were found in 24/48 (50%) patients. [111In]-octreotide scintigraphy has a higher sensitivity for tumour detection, and is superior to MR imaging and CT scanning in the identification of previously unsuspected extraliver and lymph node metastases. It may also be helpful for the localization of clinically suspected tumours in patients with MEN-I and ZES.

Effect of Helicobacter pylori eradication on antral somatostatin cell density in humans

OBJECTIVE

As Helicobacter pylori infection is associated with an elevation in plasma gastrin with normal antral gastrin cell counts, an abnormality in antral somatostatin cells may be associated with the infection. We evaluated the effect of eradication of H. pylori on antral somatostatin cell density in the light of antral gastrin cell density and plasma gastrin levels.

DESIGN

Prospective study.

METHODS

Of 25 dyspeptic patients with H. pylori infection, nine had H. pylori successfully eradicated and the rest remained infected. Antral biopsies were immunostained for somatostatin cells and plasma gastrin measured before and 4 weeks after H. pylori eradication therapy. Ten other dyspeptic patients without H. pylori infection had their somatostatin cell density evaluated as controls.

RESULTS

Somatostatin cell density in the patients without H. pylori infection at the outset was significantly higher than that in the patients with H. pylori infection at the outset (median 57 [18-83] vs. 37 [6-80] cells/mm) respectively (P <0.05). Somatostatin cell density increased after H. pylori eradication (before treatment, median 50 [15-72]; after treatment 71 [39-107] cells/mm) (P < 0.05) but was unchanged with persistent H. pylori infection. Plasma gastrin decreased after H. pylori eradication (before treatment, median 70 [45-100]; after treatment 30 [10-100] ng/l) (P < 0.05) but was unchanged with persistent H. pylori infection.

CONCLUSIONS

Following eradication of H. pylori, there is an increase in somatostatin cell density with a fall in plasma gastrin. This supports the theory that H. pylori infection results in a decrease in somatostatin cell density and, as the latter is an inhibitor of gastrin cells, this results in an increased plasma gastrin.

TFF1 gene expression in human medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is an uncommon tumour of calcitonin-secreting C-cells of the thyroid gland. This cancer represents an important potential model for the study of mechanisms of human epithelial cell transformation. Although recent studies have identified the gene involved in familial forms of MTC, little is known about the molecular pathogenesis of the sporadic variants of this tumour. The biological and prognostic significance of TFF1 expression, particularly in diverse human malignancies, suggests that the TFF1 protein could have a role in human neoplasia. Furthermore, in prostate cancer it has been demonstrated that TFF1 expression is closely associated with premalignant changes and neuroendocrine differentiation. In the present study, the expression of TFF1 was analysed in 18 human MTCs, comprising sporadic and familial tumours, C-cell hyperplasia, and one case of lymph gland metastasis. TFF1 expression was also examined in the cultures of a human MTC-derived tumour cell line (TT cell line). The results showed that ten sporadic tumours, three hereditary tumours (including C-cell hyperplasia), and one lymph gland metastasis displayed TFF1 immunoreactivity. Indirect fluorescence immunocytochemistry and Western blotting revealed that the TFF1 protein was strongly expressed in the TT cells. Northern analysis revealed that tumours and TT cells expressed the TFF1 transcript. Although the function of TFF1 protein in the carcinogenesis of MTC remains to be elucidated, its expression in the majority of cases of both sporadic and hereditary tumours, metastatic tumours, and in C-cell hyperplasia suggests that it may contribute to the pathogenesis of MTC.

The octreotide suppression test and [111In-DTPA-D-Phe1]-octreotide scintigraphy in neuroendocrine tumours correlate with responsiveness to somatostatin analogue treatment

OBJECTIVE

The somatostatin analogue octreotide (Sandostatin, Novartis, Basie) significantly improves the syndromes suffered by most patients with neuroendocrine tumours (NETs). The use of [111In-DTPA-D-Phe1]-octreotide scintigraphy ([111In]-pentetreotide) to predict the response to octreotide treatment has been described. Short-term hormone inhibition by a single injection of octreotide has also been reported. This study aimed to compare the effects of the suppression test with the response to long-term somatostatin analogue treatment, and to seek a correlation between the short-term suppression test, [11In]-pentetreotide observations and long-term somatostatin analogue treatment.

DESIGN AND MEASUREMENTS

Short octreotide suppression test and octreotide scintigraphy. Blood samples were collected before (0900, 0930 h), at (1000 h), and after (1030, 1100, 1200, 1300 h) the injection of 50 micrograms octreotide subcutaneously. Plasma hormones relevant to the syndrome were analysed by radioimmunoassay. The short suppression effects, the [111In]-pentetreotide observations and the response to long-term treatment with somatostatin analogue were evaluated and compared.

PATIENTS

Twenty-six patients with metastatic NETs were evaluated, including 14 carcinoid tumours, 10 pancreatic endocrine tumours and 2 medullary carcinomas of thyroid (MCTs). Twelve patients had received octreotide treatment before the study, another 4 patients were treated subsequently with somatostatin analogue.

RESULTS

During the short suppression test, hormones relevant to the syndromes were suppressed in 24 patients (those with carcinoids and pancreatic endocrine tumours). There was no suppression in the 2 patients with MCT. [111In]-pentetreotide observations closely correlated with the short suppression response to octreotide. Fourteen patients were treated with somatostatin analogue, and responded clinically; they had a positive short inhibition test and positive tumour uptake. Two patients with MCT did not respond to the treatment and had a negative suppression test and a negative [111In]-pentetreotide.

CONCLUSION

Our results suggest that a consistent relationship exists between the short suppression test and the response to somatostatin analogue treatment in the majority of the patients with neuroendocrine tumours. The octreotide suppression test and octreotide scintigraphy together will be helpful in selecting appropriate patients for clinical treatment with somatostatin analogues.

Expression of Bcl-2 in lung neuroendocrine tumours: comparison with p53

Several genetic aberrations have been implicated in the carcinogenesis of small cell lung carcinomas (SCLCs), including tumour suppressor gene p53 deletion and mutation and amplification of the myc family proto-oncogenes. However, their exact ontogeny and carcinogenesis remain unknown. There are no proven aetiological factors for lung carcinoid tumours. Recent evidence suggests that the genetic regulation of apoptosis is of critical importance during tumourigenesis and that oncogene and tumour suppressor genes can regulate the rate, or susceptibility, of cells to undergo apoptosis. In this study, the expression of Bcl-2 protein has been investigated in 77 primary lung neuroendocrine tumours, including 55 SCLCs and 22 carcinoid tumours, and compared with p53 expression. Of the 77 tumours studied, Bcl-2 immunoreactivity was present in 80 per cent of SCLCs, 43 per cent of typical, and 67 per cent of atypical carcinoid tumours with more than 10 per cent tumour cell positivity. Western and Northern blot analysis revealed that carcinoid tumours expressed the 26 kD protein and bcl-2 transcripts. Whereas 42 per cent of the SCLCs studied displayed p53 protein immunoreactivity in more than 10 per cent of tumour cells, p53 positivity was not found in lung carcinoid tumours. There are statistical differences in Bcl-2 and p53 expression between SCLCs and lung carcinoid tumours. These results suggest that disregulation of the genetic mechanisms controlling apoptosis is a critical step in the progression of SCLC, and the expression of Bcl-2 is involved in the pathogenesis of SCLC and lung carcinoid tumours. The genetic complementation of simultaneously deregulated Bcl-2 and p53 may be implicated in the multistep tumourigenesis of small cell lung cancer.

Exercise responses in patients with IDDM

OBJECTIVE

The hemodynamic, respiratory, and metabolic responses to exercise were studied in IDDM patients and control subjects to detect diabetic cardiomyopathy.

RESEARCH DESIGN AND METHODS

Eight subjects aged 25-40 years with diabetes of at least 10 years' duration were compared with eight control subjects aged 21-46 years. All subjects underwent a progressive incremental bicycle exercise test with measurement of gas exchange, blood glucose, lactate, fat metabolite, and catecholamine levels and two steady-state exercise tests with measurement of cardiac output by a CO2 rebreathing method. A new first-pass radionuclide method was used to measure cardiac ejection fractions (EFs) at rest, peak exercise, and steady-state exercise.

RESULTS

The peak achieved oxygen consumption was similar in the diabetic and control subjects (29.9 [25.1-34.6] and 31.4 [26.9-35.9] ml.min-1.kg-1, respectively; mean [95% CI]). There were no significant differences in heart rate, double product, ventilation, respiratory exchange ratio, or ventilatory equivalents for oxygen and CO2 during the incremental test. Glucose levels were higher in the diabetic subjects, but there were no significant differences in levels of lactate, catecholamines, free fatty acids, glycerol, or beta-hydroxybutyrate. Left ventricular EF fell from rest to peak exercise within the diabetic group (66.0% [59.6-72.4] at rest; 53.6% [45.6-61.6] at peak; P < 0.05) but this did not differ significantly from the control group (58.7% [52.3-65.1] at rest; 60.3% [48.9-71.7] at peak). Right ventricular EFs were similar in each group, and there was no reduction in peak filling rate to suggest diastolic dysfunction. The cardiac output responses to exercise were also similar in the two groups.

CONCLUSIONS

There is no evidence of impairment of the exercise response in subjects with long-standing diabetes, and the apparent fall in left ventricular EF at peak exercise could be related to hemodynamic adaptation.

Expression of apoptosis-suppressing gene bcl-2 in human carotid body tumours

That carotid body tumours have a genetic aetiology is suggested by the familial occurrence of the neoplasm. Environmental influences are also implied by the fact that the tumour is more common in those living at high altitudes. However, the mechanism of development of sporadic tumours occurring at sea level, which account for the majority of cases, remains unknown. It has become increasingly clear that the deregulation of programmed cell death is a critical component in multistep tumourigenesis. Previous studies have demonstrated a high frequency of bcl-2 expression in the tumours arising from cells derived from the neural crest and tumour cell lines of neural origin. This investigation was undertaken to determine whether similar molecular events occur in human carotid body tumours. Western and Northern analysis revealed that the tumours expressed the 26 kD protein and bcl-2 transcripts. Immunoperoxidase staining, using a monoclonal anti-bcl-2 antibody, revealed that 11 out of 13 specimens stained positively for bcl-2. These results suggest that the deregulation of programmed cell death may be a critical component in the multistep tumourigenesis of carotid body tumours and that the expression of oncoprotein bcl-2 may contribute to the generation of such tumours.

Oncogene expression in gastroenteropancreatic neuroendocrine tumors: implications for pathogenesis

BACKGROUND

Neuroendocrine tumors of the gastroenteropancreatic system include pancreatic islet cell and carcinoid tumors. These tumors comprise a functionally and biologically heterogeneous group of neoplasms that rarely show reliable histopathologic signs of malignancy. No etiologic factors are proven to be associated with them, and their exact ontogeny and carcinogenesis remain unknown.

METHODS

Monoclonal antibodies were employed, along with microwave antigen retrieval and the avidin-biotin immunohistochemical method, to investigate the expression of c-myc, bcl-2, c-erb B-2, c-erb B-3, c-jun, and proliferating cell nuclear antigen (PCNA) in a retrospective series of 116 primary gastroenteropancreatic neuroendocrine tumors (GPNTs). The authors attempted to correlate this expression with the clinicopathologic outcome of the disease.

RESULTS

Immunoreactivities for c-myc, bcl-2, c-erb B-2, c-erb B-3, and c-jun were detected in 100%, 45%, 24%, 7%, and 24% of pancreatic neuroendocrine tumors (PNTs), respectively. In carcinoid tumors, immunoreactivities were detected for c-myc (63%), bcl-2 (28%), c-erb B-2 (31%), c-erb B-3 (6%), and c-jun (23%). There were significantly higher incidences of c-myc, bcl-2, and c-erb B-2 immunoreactivities in carcinoid tumors of the rectum than in those of the appendix, and significantly higher incidences of bcl-2 and c-jun immunoreactivities in carcinoid tumors of the bronchus than in those of the appendix. Incidence of PCNA immunoreactivity was significantly higher in malignant than in benign PNTs and also significantly higher in carcinoid tumors of the jejunum and ileum than in those of the appendix.

CONCLUSIONS

The oncogenes c-myc, bcl-2, c-erb B-2, and c-jun are frequently expressed in human GPNTs. The expression of these oncogenes may represent pathogenic events in the generation, malignant transformation, and progression of GPNTs. The immunohistochemical evaluation of cell kinetics in GPNTs by PCNA might be a useful adjunct to conventional diagnostic procedures.

The epidermal nerve fibre network: characterization of nerve fibres in human skin by confocal microscopy and assessment of racial variations

As a first line of defence, the skin is equipped with a complex and interactive nerve fibre system to detect irritants and maintain homeostasis. The dermal component of this fibre network has been well characterized and fibres are known to extend throughout the viable epidermis as free nerve endings. To date, this epidermal component remains poorly characterized. We have visualized human volar forearm epidermal nerve fibres by laser-scanning confocal microscopy using the pan-neuronal marker, protein gene-product 9.5 and specific antibodies to substance P. calcitonin gene-related peptide and nerve growth factor. In addition to the varicose free nerve endings, there is a 3-D fibre network in normal human epidermis, with frequent branching of fibres. Branching can be seen to converge on a central trunk apparently extending to the dermis. Thin unmyelinated fibres can be seen in all layers of the viable epidermis. Substance P staining is rarely observed and is much less intense than the protein gene-product 9.5 staining. Calcitonin gene-related peptide and nerve growth factor were not detected in volar forearm epidermis by this method. Pretreatment of the skin in vivo with the neuropharmacological agent, capsaicin, resulted in loss of epidermal fibre staining indicating that these are sensory fibres of the primary C-afferent type. Epidermal innervation in racial and ethnic skin types was also assessed. No apparent difference in innervation was observed between European caucasian and Japanese/Chinese skin at the architectural or biochemical level, i.e. the presence, properties and biochemical content of fibres was similar in all cases tested.

Expression of a breast-cancer-associated protein (pS2) in human neuro-endocrine tumours

pS2 protein expression has been demonstrated in a range of malignant tissues in an oestrogen-independent pathway. Recently, it has been demonstrated that pS2, in prostate cancer, is closely associated with neuro-endocrine differentiation. In the present study, we have analyzed, by immunohistochemistry along with microwave antigen retrieval, the expression of pS2 protein in a retrospective series of 236 human primary neuro-endocrine tumours and attempted to correlate this with the clinicopathologic features of patients and the presence of oestrogen receptor (ER). pS2 immunoreactivity was detected in 42% of small-cell lung carcinomas, 36% of lung carcinoids, 33% of phaeochromocytomas, 38% of carotid-body tumours, 31% of pancreatic neuro-endocrine tumours, 60% of stomach carcinoids, 55% of ileal carcinoids, 23% of appendiceal carcinoids and 86% of rectal carcinoids respectively in more than 10% tumour cells. No pituitary tumours displayed pS2 immunoreactivity. pS2 transcript was also detected in lung carcinoid and carotid-body tumours by Northern-blot analysis. There was a statistically higher incidence of pS2 expression in carcinoid tumours of the ileum and rectum than in those of the appendix. No association was observed between pS2 expression and the occurrence of the carcinoid syndrome; nor was any correlation observed between the occurrence of pS2 immunoreactivity and that of ER. Our results suggest that the expression of the pS2 protein in a wide spectrum of neuro-endocrine tumours may be implicated in the pathogenesis and progression of some neuro-endocrine tumours in an oestrogen-independent pathway.

Expression of the apoptosis-suppressing gene BCL-2 in pheochromocytoma is associated with the expression of C-MYC

It has become increasingly clear that deregulation of programmed cell death is a critical component in multistep tumorigenesis. Previous studies have demonstrated a high frequency of Bcl-2 expression in tumors arising from cells derived from the neural crest and in tumor cell lines of neural origin. The present investigation was undertaken to determine whether similar molecular events occur in human pheochromocytoma. With the aim of determining the potential role of apoptosis in the pathogenesis of this tumor, we assessed proto-oncogene Bcl-2 and c-myc protein products as well as Bcl-2 messenger RNA levels in a collection of such tumors. Western blot analysis revealed that such tumors expressed the 26 kDa Bcl-2 (5 of 8 cases) and the 64 kDa c-Myc (7 of 8 cases) proteins. Northern blot analysis detected the Bcl-2 transcripts in 6 of 8 tumors. Immunoperoxidase staining, using a monoclonal anti-Bcl-2 antibody, was positive in 18 (82%), including 5 malignant tumors, of the 22 specimens examined. This Bcl-2 immunoreactivity was seen in 14 of 18 (78%) sporadic tumors, including 2 that were extra-adrenal, and all familial tumors. Of the 22 tumor samples examined for c-Myc protein, 20 (91%) tumors were positive. Our results suggest that deregulation of programmed cell death may be a critical component in the multistep tumorigenesis of human pheochromocytoma. The genetic complementation of simultaneously deregulated Bcl-2 and c-myc may be implicated in this process.

Responses of atrial natriuretic peptide and brain natriuretic peptide to exercise in patients with chronic heart failure and normal control subjects

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are known to be elevated in patients with chronic heart failure at rest. While it is known that during exercise the circulating level of ANP increases in patients with heart failure, the response of BNP to exercise in these patients relative to control subjects is unclear. Ten patients with stable chronic heart failure and 10 normal control subjects performed symptom-limited exercise with respired gas analysis. All patients had depressed left ventricular ejection fractions (LVEF). Patients had lower peak oxygen consumption PVo2) than the control group [median (range) 1.18 (0.98-1.76) vs. 1.94 (1.53-2.31) L min-1; P < 0.001]. Circulating plasma levels of ANP and BNP were higher at rest in patients than in control subjects [ANP 335 (140-700) vs. 90 (25-500) pg mL-1; BNP 42 (25-50) vs. 20 (10-20) pg mL-1], and at peak exercise [ANP 400 (200-1000) vs. 130 (10-590); BNP 46 (40-51) vs. 20 (10-30)]. The rise in ANP at peak exercise was significant in patients compared with the resting level, but not in control subjects. For BNP, there was a significant rise in patients but no change in control subjects. The circulating plasma levels of both peptides showed a strong negative correlation with LVEF (ANP, P < 0.005; BNP, P < 0.0001) and, to a less extent, with RVEF. It is possible that BNP may give a better indication of cardiac function.

Stability of plasma concentrations of N- and C-terminal atrial natriuretic peptides at room temperature

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Ontogenetic expression of chromogranin A and its derived peptides, WE-14 and pancreastatin, in the rat neuroendocrine system

The ontogenetic expression of chromogranin A (CgA) and its derived peptides, WE-14 and pancreastatin (PST), was studied in the rat neuroendocrine system employing immunohistochemical analysis of fetal and neonatal specimens from 12.5-day embryos (E12.5), to 42-day postnatal (P42) rats. CgA immunostaining was first detected in endocrine cells of the pancreas, stomach, intestine, adrenal gland and thyroid at E13.5, E14.5, E15.5, E15.5 and E18.5, respectively. PST-like immunoreactivity was detected in endocrine cells of the pancreas at E13.5, stomach, intestine at E15.5, adrenal gland at E17.5 and thyroid at E18.5. WE-14 immunoreactivity was first observed in the immature pancreas at E15.5, mucosal cells of the stomach at E15.5, scattered chromaffin cells in the immature adrenal gland and mucosal cells of the intestine at E17.5 and thyroid parafollicular cells at E18.5. These data confirm that the translation of the CgA gene is regulated differentially in various neuroendocrine tissues and, moreover, suggests that the post-translational processing of the molecule is developmentally controlled.

The effect of the neutral endopeptidase inhibitor drug, candoxatril, on circulating levels of two of the most potent vasoactive peptides

AIMS

Candoxatril is a specific neutral endopeptidase (NEP) 24.11 inhibitor, and previous work has documented the effect of NEP inhibition on atrial and brain natriuretic peptides (ANP, BNP). The aim of the present study was to ascertain the effect of NEP inhibition on circulating levels of vasoactive peptides.

METHODS

We studied seven patients with chronic heart failure who were randomized to receive candoxatril, candoxatril/captopril, captopril and placebo in a four way cross over, double-blind pattern.

RESULTS

The mean circulating level of endothelin (ET) was increased 2 h after placebo (10 to 20 pg ml-1) and also calcitonin gene-related peptide (CGRP) (27 to 51 pg ml-1), but ANP levels changed little during this time (73 to 75 pg ml-1). Following candoxatril, however, ET (10 to 39 pg ml-1, P < 0.05), CGRP (34 to 99 pg ml-1, P < 0.05) and ANP (72 to 108 pg ml-1, P < 0.05) increased further. A similar result was observed following combined treatment with candoxatril and captopril.

CONCLUSIONS

We conclude that neutral endopeptidase inhibition increases circulating plasma levels of ET and CGRP in addition to the natriuretic peptides.

Regulatory peptides and other neuroendocrine markers in medullary carcinoma of the thyroid

Medullary thyroid carcinoma (MTC) is an APUDoma (APUD refers to amine precursor uptake and decarboxylation) arising from the parafollicular cells. Diarrhoea has been reported in some 30% of patients, variously attributed to excess production of calcitonin (CT), serotonin (5-HT), vasoactive intestinal peptide (VIP) or other factors. The regulatory factors in MTC were examined employing immunocytochemistry and RIA to tumours and their extracts. The patients were followed up for more than 15 years. CT and calcitonin gene-related peptide were universally expressed in all the tumours. The neuroendocrine markers chromogranin A (and its fragments pancreastatin and WE-14), neurone-specific enolase, protein gene product 9.5 and carcino-embryonic antigen were found in the majority of MTCs and might be useful as immunocytochemical markers. 5-HT, substance P, neurokinin A, glucagon and VIP could not be detected, excluding them as candidates in the diarrhoea of MTC.

Occurrence of WE-14 and chromogranin A-derived peptides in tissues of the human and bovine gastro-entero-pancreatic system and in human neuroendocrine neoplasia

Antisera were generated to the synthetic peptides SREWEDS and KELTAE which correspond to residues 315-321 and 332-337 of human chromogranin A (CgA) respectively. KELTAE represents the C-terminal hexapeptide of WE-14, and SREWEDS (residue 316 human CgA Lys/Arg substitution) represents the C-terminal heptapeptide of the Intervening Peptide, located between pancreastatin and WE-14. The antisera were employed to study the occurrence of WE-14 and CgA-derived peptides in human and bovine gastro-entero-pancreatic (GEP) tissues and in a range of human GEP neuroendocrine tumours. Immunocytochemical analyses of normal human and bovine tissues demonstrated that each antiserum immunostained endocrine cells throughout the GEP tract, Variable intensities of immunostaining were detected in neoplastic tissues. Quantitatively, the highest levels of SREWEDS and KELTAE immunoreactivity were detected in pancreatic extracts, with lower levels in gastrointestinal tissues. Elevated levels of each immunoreactant were detected in neoplastic tissues. Chromatographic analysis resolved several SREWEDS-related peptides and a major KELTAE-related peptide that co-eluted with synthetic human WE-14. The present study has demonstrated that CgA is processed to generate distinct peptide products in normal and neoplastic tissues of the GEP system. A single molecular species co-eluting with synthetic human WE-14 was predominant and consistently detected in all the tissues studied.

Normalization of insulin responses to glucose by overnight infusion of glucagon-like peptide 1 (7-36) amide in patients with NIDDM

Glucagon-like peptide 1 (GLP-1) is a natural enteric incretin hormone, which is a potent insulin secretogogue in vitro and in vivo in humans. Its effects on overnight glucose concentrations and the specific phases of insulin response to glucose and nonglucose secretogogues in subjects with NIDDM are not known. We compared the effects of overnight intravenous infusion of GLP-1 (7-36) amide with saline infusion, on overnight plasma concentrations of glucose, insulin, and glucagon in eight subjects with NIDDM. The effects on basal (fasting) beta-cell function and insulin sensitivity were assessed using homeostasis model assessment (HOMA) and compared with seven age- and weight-matched nondiabetic control subjects. The GLP-1 infusion was continued, and the first- and second-phase insulin responses to a 2-h 13 mmol/l hyperglycemic clamp and the insulin response to a subsequent bolus of the nonglucose secretogogue, arginine, were measured. These were compared with similar measurements recorded after the overnight saline infusion and in the control subjects who were not receiving GLP-1. The effects on stimulated beta-cell function of lowering plasma glucose per se were assessed by a separate overnight infusion of soluble insulin, the rate of which was adjusted to mimic the blood glucose profile achieved with GLP-1. Infusion of GLP-1 resulted in significant lowering of overnight plasma glucose concentrations compared with saline, with mean postabsorptive glucose concentrations (2400-0800) of 5.6 +/- 0.8 and 7.8 +/- 1.4 mmol/l, respectively (P < 0.0002). Basal beta-cell function assessed by HOMA was improved from geometric mean (1 SD range), 45% beta (24-85) to 91% beta (55-151) by GLP-1 (P < 0.0004). First-phase incremental insulin response to glucose was improved by GLP-1 from 8 pmol/l (-8-33) to 116 pmol/l (12-438) (P < 0.005), second-phase insulin response to glucose from 136 pmol/l (53-352) to 1,156 pmol/l (357-3,748) (P < 0.0002), and incremental insulin response to arginine from 443 pmol/l (172-1,144) to 811 pmol/l (272-2,417) (P < 0.002). All responses on GLP-1 were not significantly different from nondiabetic control subjects. Reduction of overnight glucose by exogenous insulin did not improve any of the phases of stimulated beta-cell function. Prolonged intravenous infusion of GLP-1 thus significantly lowered overnight glucose concentrations in subjects with NIDDM and improved both basal and stimulated beta-cell function to nondiabetic levels. It may prove to be a useful agent in the reduction of hyperglycemia in NIDDM.

Expression of bcl-2 oncoprotein in pituitary tumours: comparison with c-myc

AIMS/BACKGROUND

Whereas the control of hormone secretion from pituitary adenomas has been studied in considerable detail, the molecular events underlying the development of these tumours are still poorly understood. Abnormalities of some oncogenes and tumour suppressor genes have been previously reported to occur at very low frequencies. The aim of the present study was to assess the possible expression of the bcl-2 oncoprotein and to compare it with that of c-myc in pituitary adenomas.

METHODS

Monoclonal antibodies were used, along with microwave antigen retrieval and the avidin-biotin immunohistochemical method, to investigate expression of the oncoproteins bcl-2 and c-myc in 30 primary pituitary tumours from five broad diagnostic groups and in five normal pituitaries.

RESULTS

Bcl-2 and c-myc immunoreactivities were detected in nine (30%) and eight (27%) tumour samples, respectively. Of the nine bcl-2 and eight c-myc positive tumours, seven were positive for both oncoproteins and included one of the four corticotrophinomas studied, four of seven prolactinomas, one of two somatotrophinomas, and one of four oncocytomas. All 13 null cell adenomas studied were negative for both bcl-2 and c-myc immunoreactivities.

CONCLUSIONS

These results indicate that the bcl-2 and c-myc oncoproteins are expressed abnormally in over one quarter of pituitary tumours. Most these tumours co-expressed both oncoproteins. The genetic complementation of simultaneously deregulated bcl-2 and c-myc is implicated, through the regulation of apoptosis, in the pathogenesis of pituitary tumours.

Clinical studies of multiple endocrine neoplasia type 1 (MEN1)

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid, pancreatic islet and anterior pituitary tumours. To facilitate a screening programme for MEN1, we investigated 709 people (364 males and 345 females, age range 1-84 years) from 62 MEN1 families, and 36 non-familial MEN1 patients. Of those investigated, 220 (95 males and 125 females, age range 8-79 years) suffered from MEN1. Parathyroid, pancreatic and pituitary tumours occurred in 95%, 41% and 30% of the patients, respectively. Parathyroid tumours were the first manifestation of MEN1 in 87% of patients, and amongst the pituitary and pancreatic tumours, somatotrophinomas and gastrinomas were more common in patients above the age of 40 years, whilst insulinomas occurred more frequently in patients below the age of 40 years. Biochemical screening indicated that the penetrance of MEN1 by the ages of 20, 35 and 50 years was 43%, 85% and 94%, respectively, and that the development of MEN1 was confined to first-degree relatives in 91% of patients and to second-degree relatives in 9% of patients. These findings have helped to define a proposed screening programme for MEN1.

Oncogene expression in carotid body tumors

BACKGROUND

The genetic etiology of carotid body tumors is suggested by the familial occurrence of the neoplasm. Environmental influences are also implied by the fact that the tumor is more common in those living at high altitudes. However, the development of sporadic tumors occurring at sea level, which account for the majority of cases, remains unknown.

METHODS

The clinical and pathologic features of 13 carotid body tumors excised in 13 patients were reviewed. Two patients had bilateral tumors, one with a strong family history, and two patients had recurrent carotid body tumors. All tumors were benign except for one that had local lymph gland metastases. All patients were followed up for a period ranging from 1 to 17 years. Each tumor was examined for the oncoproteins c-myc, bcl-2 c-erbB-2, c-erbB-3 and c-jun and for the proliferating cell nuclear antigen (PCNA) by immunohistochemistry.

RESULTS

c-myc immunoreactivity was observed in all tumors and, in 12 of 13 cases, was present in more than 10% of tumor cells, bcl-2 immunoreactivity was found in 11 cases with 6 tumors exhibiting more than 10% immunopositive cells, c-jun expression was found in 5 cases with 3 tumors containing more than 10% immunopositive cells. Only two tumors were positive for c-erb-B2 immunoreactivity with a cytoplasmic staining pattern. One tumor was positive for c-erb-B3.

CONCLUSIONS

The oncogenes c-myc, bcl-2 and c-jun, are abnormally expressed in some carotid body tumors. Their expression may contribute to the genesis of carotid body tumors.

Serum neurone-specific enolase as an indicator of stroke volume

Serum neurone-specific enolase (NSE) and computerized tomography (CT) stroke volume were compared in patients admitted within 24 h of an acute stroke. Serum samples were obtained on admission and daily for the next 4 days. Of 163 patients, CT scans revealed 25 with intracerebral haemorrhages, one haemorrhagic infarct and 83 measurable acute infarcts. The serum NSE levels of those with infarcts was significantly higher than in those with haemorrhages at 48 (P = 0.0003) and 72 h (P = 0.04). The maximum serum NSE value tended to occur later in those with large infarcts (P = 0.0035). There was a significant correlation between infarct volume and serum NSE at 48 h (r = 0.27, P = 0.015) and 96 h (r = 0.27, P = 0.015) and with the maximum serum NSE over the 4 days (r = 0.36, P = 0.001). There was no significant correlation between haemorrhage volume and NSE. In conclusion, serum NSE may be a useful marker of infarct volume in studies of therapy in acute stroke. Sampling for NSE should continue, at least in those with large infarcts, for longer than 4 days. Serum NSE cannot be used to distinguish between haemorrhage and infarction in patients with an acute stroke.

PC12 cells show immunoreactivity to a number of proteins and peptides, including vasostatin

N-terminal chromogranin A (CGA) contains peptides with vasoinhibitory properties, called vasostatin I (VST) and II [CGA (1-76) and (1-113) in human and bovine; (1-128) in rat]. Three fragments of VST were synthesized and antisera raised: human CGA (68-76) (VST I) rat CGA (121-128) (VST II fragment 2), and bovine/human CGA (83-91) (VST II, fragment 3). Strong immunoreactivity was observed in PC12 cells with antisera to VST II, fragment 3, VST I, and neuron-specific enolase. Little or no immunoreactivity was observed using antisera to synaptophysin, whole molecule CGA, pancreastatin, protein gene product 9.5, somatostatin, pancreatic polypeptide, or with antibodies 875 and 876 to VST II, fragment 2. Most of the VST antisera cross-reacted, with a species of molecular weight, 61 kDa but one, 874, cross-reacted with two species of molecular weights, 7.2 and 12 kDa. Our results show the presence of N-terminally processed CGA in PC12 cells.

Neuroendocrine changes in chronic cardiac failure

Numerous hormonal and neuroendocrine changes have been described in patients with chronic cardiac failure. These affect the balance of vasodilator and vasoconstrictor factors in favour of the latter, to the detriment of the circulation. Whether this is a reaction to central cardiac (haemodynamic) abnormalities, or is an integral part of the syndrome of heart failure, remains to be determined. Catecholamine levels are increased, especially in severe heart failure, and contribute to the vasoconstriction and probably also to lethal ventricular arrhythmias. The renin-angiotensin-aldosterone system (RAAS) is also activated, causing fluid retention and further vasoconstriction. In the earlier stages, some of this increase may be iatrogenic due to the use of loop diuretics or inhibitors of angiotensin converting enzyme, but there is evidence for independent RAAS activation in more severe grades of heart failure. The role of vasoconstrictor peptides such as neuropeptide Y and endothelin is briefly considered. Counterbalancing these are vasodilator peptides, in particular atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP). The possibility of therapeutic interventions to increase circulating natriuretic hormone levels is discussed.