Glucagon-like peptide-1 (GLP-1) receptors are not overexpressed in pancreatic islets from patients with severe hyperinsulinaemic hypoglycaemia following gastric bypass

AIMS/HYPOTHESIS

Glucagon-like peptide-1 (GLP-1) receptors are highly overexpressed in benign insulinomas, permitting in vivo tumour visualisation with GLP-1 receptor scanning. The present study sought to evaluate the GLP-1 receptor status in vitro in other pancreatic disorders leading to hyperinsulinaemic hypoglycaemia, specifically after gastric bypass surgery.

METHODS

Fresh frozen pancreatic tissue samples (n=7) from six gastric bypass surgery patients suffering from hyperinsulinaemic hypoglycaemia were evaluated for GLP-1 receptor content using in vitro receptor autoradiography, and compared with normal pancreas and with pancreatic insulinoma tissues.

RESULTS

GLP-1 receptor analysis of the pancreatic tissues, which histopathologically were compatible with nesidioblastosis and originated from post-bypass hypoglycaemic patients, revealed a mean density value of GLP-1 receptors in the islets of 1,483 ± 183 dpm/mg tissue. Pharmacological characterisation indicated the presence of specific GLP-1 receptors. The density of islet GLP-1 receptor in post-gastric bypass patients did not differ from that of normal pancreas (1,563 ± 104 dpm/mg tissue, n = 10). Receptor density in pancreatic acini was low in post-bypass and control conditions. In contrast, benign insulinomas showed a high density of GLP-1 receptors, with a mean value of 8,302 ± 1,073 dpm/mg tissue (n = 6).

CONCLUSIONS/INTERPRETATION

In contrast to insulinoma, hyperinsulinaemic hypoglycaemia after gastric bypass surgery is not accompanied by overexpression of GLP-1 receptor in individual islets. Thus, patients with post-gastric bypass hyperinsulinaemic hypoglycaemia are not candidates for GLP-1 receptor imaging in vivo using radiolabelled exendin. These GLP-1 receptor data support the notion that the islet pathobiology of post-gastric bypass hypoglycaemia is distinctly different from that of benign insulinomas.

A model of ischemic isolated acute liver failure in pigs: standardizing monitoring and treatment

BACKGROUND

Acute liver failure (ALF) models in pigs have been widely used for evaluating newly developed liver support systems. But hardly any guidelines are available for the surgical methods and the clinical management.

METHODS

The study validated several standard operating procedures describing in detail the surgical method and intensive care monitoring and treatment (control of potassium, glucose and bicarbonate levels, cardiovascular and intracranial pressure monitoring, etc.). ALF was induced in animals with a mean of 56 kg. Two surgical methods were compared: ligation of hepatic arteries with either end-to-side portacaval shunt (ESPS) and bile duct ligation or side-to-side portacaval shunt (SSPS) without bile duct ligation.

RESULTS

During total portal vein clamping, the animals in the ESPS group developed severe hypotension, splanchnic congestion and metabolic acidosis. One animal died after approximately 1.5 h. This model therefore represents a multiorgan failure model rather than an isolated ALF model. In the SSPS group, none of these side effects were observed, while clinical, laboratory and histopathological signs of ALF were evident.

CONCLUSIONS

A reproducible model in pigs representing ALF can be established with the help of the standardized monitoring and treatment procedures presented.

VHL inactivation is an important pathway for the development of malignant sporadic pancreatic endocrine tumors

A small subset of familial pancreatic endocrine tumors (PET) arises in patients with von Hippel-Lindau syndrome and these tumors may have an adverse outcome compared to other familial PET. Sporadic PET rarely harbors somatic VHL mutations, but the chromosomal location of the VHL gene is frequently deleted in sporadic PET. A subset of sporadic PET shows active hypoxia signals on mRNA and protein level. To identify the frequency of functionally relevant VHL inactivation in sporadic PET and to examine a possible prognostic significance we correlated epigenetic and genetic VHL alterations with hypoxia signals. VHL mutations were absent in all 37 PETs examined. In 2 out of 35 informative PET (6%) methylation of the VHL promoter region was detected and VHL deletion by fluorescence in situ hybridization was found in 14 out of 79 PET (18%). Hypoxia inducible factor 1alpha (HIF1-alpha), carbonic anhydrase 9 (CA-9), and glucose transporter 1 (GLUT-1) protein was expressed in 19, 27, and 30% of the 152 PETs examined. Protein expression of the HIF1-alpha downstream target CA-9 correlated significantly with the expression of CA-9 RNA (P<0.001), VHL RNA (P<0.05), and VHL deletion (P<0.001) as well as with HIF1-alpha (P<0.005) and GLUT-1 immunohistochemistry (P<0.001). These PET with VHL alterations and signs of hypoxia signalling were characterized by a significantly shortened disease-free survival. We conclude that VHL gene impairment by promoter methylation and VHL deletion in nearly 25% of PET leads to the activation of the HIF-pathway. Our data suggest that VHL inactivation and consecutive hypoxia signals may be a mechanism for the development of sporadic PET with an adverse outcome.

Omitted and unjustified medications in the discharge summary

BACKGROUND

Limited information exists in regard to drug omissions and unjustified medications in the hospital discharge summary (DS).

OBJECTIVE

To evaluate the incidence and types of drug omissions and unjustified medications in the DS, and to assess their potential impact on patient health.

METHODS

A prospective observational review of the DSs of all patients discharged from our Internal Medicine Department over a 3-month period. Data assessment was made by internists using a structured form.

RESULTS

Of the 577 evaluated DSs, 66% contained at least one inconsistency accounting for a total of 1012 irregularities. There were 393 drug omissions affecting 251 patients, 32% of which were potentially harmful. Seventeen per cent of all medications (619/3691) were unjustified, affecting 318 patients. The unjustified medication was potentially harmful in 16% of cases, occurred significantly more frequent in women than in men (61% vs 50%; p = 0.008) and increased linearly with the number of drugs prescribed (p<0.001). Drug omission had a twofold higher potential to cause harm than unjustified medication.

CONCLUSIONS

Drug omissions and unjustified medications are frequent, and systemic changes are required to substantially reduce these inconsistencies.

Economic burden of unjustified medications at hospital discharge

QUESTION UNDER STUDY

Medication errors are a major concern for health care since they may cause or lead to inappropriate medication use or patient harm. However, little is known regarding the economic burden of unjustified medications.

METHODS

Hospital discharge records of 577 patients were prospectively screened for the presence of unjustified medications. From this sample population, 318 (55%) were eligible and their data were used to assess the monthly costs of unjustified discharge medications, their relationship to the total and each individual's drug expenditure, and the relative cost weights of relevant unjustified drug classes.

RESULTS

The results found that 619 out of 3691 prescriptions (16.8%) were unjustified. The mean (median; 95% CI) monthly costs of unjustified discharge medications were 32 euro (27 euro; 29 euro to 35 euro). The percentage of unnecessary treatments was inversely linked to the amount of total individual drug expenditure. For this collective, monthly extra costs due to unjustified medications were 18585 euro, and the relative cost weights of the relevant drug classes were 45.8% for gastrointestinal agents (33.8% for proton pump inhibitors), 17.7% for cardiovascular drugs, and 17.2% for psychiatric drugs.

CONCLUSIONS

There is a considerable financial burden imposed by unjustified medications at hospital discharge. Discharge medications not motivated by appropriate diagnoses should be questioned. This study should be repeated in other institutions and in a larger population.

[Classification of gastro-entero-pancreatic neuroendocrine tumors]

Tumors of the disseminated/diffuse neuroendocrine system (NET) are characterized by a common phenotype. However, the biology varies according to histomorphology, endocrine symptoms and organ of origin. The WHO classification takes these differences into account and uses a common framework, where the parameters size and extent of invasion vary according to the organ of origin. In order to achieve a further standardization of reporting the European Neuroendocrine Tumor Society (ENETS) recently proposed a tumor-node-metastasis (TNM) staging and grading system for gastro-entero-pancreatic NET.

Hyperglycaemia but not hyperlipidaemia causes beta cell dysfunction and beta cell loss in the domestic cat

AIMS/HYPOTHESIS

In vitro studies point to a toxic effect of high glucose and non-esterified fatty acids on beta cells. Whether elevated levels of glucose and lipids induce beta cell loss in vivo is less clear. The domestic cat has recently been proposed as a valuable animal model for human type 2 diabetes because feline diabetes shows several similarities with diabetes in humans, including obesity-induced insulin resistance, impaired beta cell function, decreased number of beta cells and pancreatic amyloid deposition.

METHODS

We infused healthy cats with glucose or lipids for 10 days to clamp their blood concentrations at the approximate level found in untreated feline diabetes (glucose: 25-30 mmol/l; triacylglycerols: 3-7 mmol/l).

RESULTS

Glucose and lipid levels were adequately targeted. Plasma non-esterified fatty acids were increased by lipid infusion 1.7-fold. A dramatic and progressive decline of plasma insulin levels was observed in glucose-infused cats beginning after 2 days of hyperglycaemic clamp. In contrast, plasma insulin concentration and glucose tolerance test were not affected by hyperlipidaemia. Compared with controls, glucose-infused cats had a 50% decrease in beta cells per pancreatic area. Apoptotic islet cells and cleaved caspase-3-positive beta cells were observed in glucose-infused cats only.

CONCLUSIONS/INTERPRETATION

Sustained hyperglycaemia but not hyperlipidaemia induces early and severe beta cell dysfunction in cats, and excess glucose causes beta cell loss via apoptosis in vivo. Hyperglycaemic clamps in cats may provide a good model to study the pathogenesis of glucose toxicity in beta cells.

DNA copy number status is a powerful predictor of poor survival in endocrine pancreatic tumor patients

The clinical behavior of endocrine pancreatic tumors (EPTs) is difficult to predict in the absence of metastases or invasion to adjacent organs. Several markers have been indicated as potential predictors of metastatic disease, such as tumor size > or =2 cm, Ki67 proliferative index > or =2%, cytokeratin (CK) 19 status, and recently in insulinomas, chromosomal instability (CIN). The goal of this study was to evaluate the value of these markers, and in particular of the CIN, to predict tumor recurrence or progression and tumor-specific death, using a series of 47 insulinomas and 24 non-insulinoma EPTs. From these EPT cases, a genomic profile has been generated and follow-up data have been obtained. The proliferative index has been determined in 68 tumors and a CK19 expression pattern in 50 tumors. Results are statistically analyzed using Kaplan-Meier plots and the log-rank statistic. General CIN, as well as specific chromosomal alterations such as 3p and 6q loss and 12q gain, turned out to be the most powerful indicators for poor tumor-free survival (P< or =0.0004) and tumor-specific death (P< or =0.0113) in insulinomas. The CIN, chromosome 7q gain, and a proliferative index > or =2% were reliable in predicting a poor tumor-free survival in non-insulinoma EPTs (P< or =0.0181, whereas CK19 expression was the most optimal predictor of tumor-specific death in these tumors. In conclusion, DNA copy number status is the most sensitive and efficient marker of adverse clinical outcome in insulinomas and of potential interest in non-insulinoma EPTs. As a consequence, this marker should be considered as a prognosticator to improve clinical diagnosis, most practically as a simple multi-target test.

TNM staging of midgut and hindgut (neuro) endocrine tumors: a consensus proposal including a grading system

Criteria for the staging and grading of neuroendocrine tumors (NETs) of midgut and hindgut origin were established at the second Consensus Conference in Frascati (Rome) organized by the European Neuroendocrine Tumor Society (ENETS). The proposed tumor-node-metastasis (TNM) classifications are based on the recently published ENETS Guidelines for the Diagnosis and Treatment of gastroenteropancreatic NETs and follow our previous proposal for foregut tumors. The new TNM classifications for NETs of the ileum, appendix, colon, and rectum, and the grading system were designed, discussed, and consensually approved by all conference participants. These proposals need to be validated and are meant to help clinicians in the stratification, treatment and follow-up of patients.

Neoadjuvant gemcitabine/cisplatin for resectable adenocarcinoma of the pancreatic head—a prospective phase I trial

15095

Background: Pancreatoduodenectomy (PD) alone was considered a standard treatment for cancer of the pancreatic head for a long time before the recent advent of adjuvant chemotherapy (CTX). Since adjuvant chemotherapy cannot be applied to all patients (pts), and neoadjuvant chemoradiation is toxic, we initiated a prospective phase II trial in August 2001 to test the safety and outcome of neoadjuvant CTX without radiation for resectable pancreatic cancer. Methods: Pts with cytologically confirmed resectable ductal adenocarcinoma of the pancreatic head were eligible for this phase II trial. Staging and restaging examinations included chest and abdominal CT-scan, endoscopic ultrasound with cytology, PET/CT and diagnostic laparoscopy. CTX consisted of four treatments of gemcitabine (1000mg/m2) and cisplatin (50mg/m2) every two weeks, and PD was planned at week 8. CA 19–9, prealbumin serum levels, and quality of life (QLQ- 30) were also determined before and after CTX. The primary study end-point was resectability based on re-staging examinations. Follow-up CT- scans were performed every six months. Results: Thirty-one pts entered this trial. Of these, 27 completed CTX and restaging until analysis. At restaging two pts had peritoneal metastases resulting in a resectability rate of 93% (25/27). No grade IV, and 7 transient grade III toxicities occurred in five pts. Median progression-free and overall survival after diagnosis were 9.2 months (95% CI 7.7–10.8) and 26.5 months (95% CI 15.2–37.7), respectively, for resected pts. After CTX, CA 19–9 serum levels were decreased by 48% (p=0.01). Moreover, the overall quality of life was increased by 24% (p=0.02). Prealbumin serum levels were abnormal in 40% of the pts on study entry, and normal in all but 89% after CTX (p=0.02). Conclusions: Neoadjuvant gemcitabine/cisplatin over two months is well tolerated and does not jeopardize resectability of adenocarcinoma of the pancreatic head. It offers several advantages including patient selection for surgery, improvements in the nutritional status and quality of life. A randomized trial comparing adjuvant and neoadjuvant+adjuvant treatment is being planned.

No significant financial relationships to disclose.

Allelic deletion of the MEN1 gene in duodenal gastrin and somatostatin cell neoplasms and their precursor lesions

BACKGROUND

Patients with a multiple endocrine neoplasia type 1 (MEN1)-associated Zollinger-Ellison syndrome (ZES) show multifocal duodenal gastrinomas and precursor lesions.

AIMS

To test these lesions for loss of heterozygosity (LOH) of the MEN1 gene locus on chromosome 11q13, and to investigate whether the MEN1-related endocrine cell changes also involved somatostatin cells.

MATERIAL AND METHODS

Tissue specimens from six patients with MEN1 and ZES were analysed by immunohistochemistry and immunofluorescence. LOH analysis was performed by fluorescence in situ hybridisation (FISH), using probes containing the MEN1 gene locus and the centromere 11 (C11) region. For simultaneous analysis of hormones and allelic deletions, a combined FISH/immunofluorescence protocol was established.

RESULTS

28 of a total of 33 duodenal neuroendocrine tumours (NETs) were gastrin-producing tumours; 13/28 (46.4%) revealed LOH on 11q13 and/or C11. Five of the NETs were somatostatin-expressing tumours, two revealing LOH. Allelic loss was detected in tumours as small as 300 microm (gastrin) and 400 microm (somatostatin) in diameter. The gastrin-producing tumours showed different deletion/retention patterns. Hyperplastic somatostatin cell lesions, similar to those of the gastrin cells, were present in all patients. The hyperplastic lesions of both cell lines consistently retained both 11q13 alleles.

CONCLUSIONS

Allelic deletion of the MEN1 gene may reflect a pivotal event in the development of multifocal gastrin and somatostatin cell neoplasms in the duodenum of patients with MEN1. The observation of distinct deletion patterns in small synchronous tumours supports the concept that each gastrin-producing tumour in an individual MEN1 patient arises from an independent cell clone.

Histological evaluation of the adrenal glands of seven dogs with hyperadrenocorticism treated with trilostane

The lesions in the adrenal glands of seven dogs with hyperadrenocorticism that had been treated with trilostane were studied histologically. The glands of the six dogs with pituitary-dependent hyperadrenocorticism had moderate to severe cortical hyperplasia that was either diffuse or nodular. The lesions were more pronounced in the zona fasciculata than in the zona reticularis, and the zona glomerulosa was normal. In the dog with a functional adrenal tumour the non-tumour bearing adrenal gland showed mild nodular hyperplasia. Five of the seven dogs had variable degrees of adrenal necrosis, which was severe in two of them. The terminal deoxynucleotidyl transferase-mediated DUTP nick-end labelling (TUNEL) reaction specified areas of cell death as apoptosis in three of the dogs, and was positive in one of the dogs without visible areas of cell death. There were variable degrees of cortical haemorrhage in three of the dogs. In some of the dogs the lesions were severe enough to lead to hypoadrenocorticism.

[Non infectious postoperative fever]

We present the case of a 74-years old man with subtotal gastrectomy for adenocarcinoma, whose postoperative course is complicated by a prolonged fever. Despite extensive diagnostics, the origin of the postoperative fever remains unexplained for 47 days, when the patient is transferred to the ICU because of lethargy, hemodynamic instability, lung edema and abdominal symptoms. The diagnosis of Addison crisis is established and under substitution with hydrocortisone all the symptoms rapidly resolve. Postoperative fever is relatively frequent and infectious causes account for about half of the cases only. An infectious origin has imperatively to be excluded when the fever arises later than 48 hrs after surgery. In case of prolonged fever we suggest to extend the differential diagnosis to other than infectious causes by means of special lists (e.g fever of unknown origin).

An unusual case of a highly progressive supratentorial capillary haemangioblastoma - histopathological considerations

We describe a case of a rapidly progressive, sporadic, non-von Hippel-Lindau (VHL) disease associated supratentorial capillary haemangioblastoma. Despite the classical histopathological presentation consisting of stromal cells and abundant capillaries, the tumour showed an unfavourable clinical course.

[Gastrin cell hyperplasia associated with duodenal MEN1-related gastrinomas: histopathology and genetics]

AIMS

The identification of precursor lesions has a great impact on our understanding of tumorigenesis. In this study we investigated whether preneoplastic lesions can be identified in sporadic gastrinomas and in gastrinomas in multiple endocrine neoplasia type 1 (MEN1) patients. These lesions were tested for loss of heterozygosity (LOH) of the MEN1 gene locus on chromosome 11q13.

MATERIAL AND METHODS

Tissue specimens from 25 patients with Zollinger-Ellison syndrome (ZES) were analyzed. The MEN1 status was assessed clinically and by mutational analysis. For simultaneous analysis of hormones and allelic deletions a combined FISH fluorescence in situ hybridization/immunofluorescence protocol was established.

RESULTS

Hyperplastic gastrin cell lesions were present in the nontumorous mucosa of all MEN1 patients, but not in 12 patients with sporadic duodenal gastrinomas. The hyperplastic gastrin cells retained both 11q13 alleles. 11q13 LOH was, however, detected in duodenal gastrinomas, some as small as 300 microm in diameter, in 13 patients with MEN1.

CONCLUSIONS

MEN1-associated duodenal gastrinomas, but not sporadic gastrinomas, are associated with gastrin cell hyperplasia. It is therefore likely that hyperplastic gastrin cell lesions precede the development of MEN1-associated duodenal gastrinomas. Allelic deletion of the MEN1 gene locus may reflect a decisive initial event in the development of multifocal MEN1-associated gastrinomas from hyperplastic gastrin cell lesions.

Genetic analyses of apparently sporadic pheochromocytomas: the Rotterdam experience

Pheochromocytomas (PCCs) are neuroendocrine tumors of chromaffin tissue that produce catecholamines. They are usually located in the adrenal medulla, although in about 10% the tumors arise from extra-adrenal chromaffin tissue. The majority of PCCs arise sporadically, but PCCs occur also in the context of hereditary cancer syndromes. Familial PCC is inherited as an autosomal dominant trait alone or as a component of the multiple endocrine neoplasia Type 2 (MEN2) syndrome (RET gene), Von Hippel-Lindau (VHL) disease (VHL gene), neurofibromatosis Type 1 (NF1 gene), or familial pheochromocytoma-paraganglioma (PCC-PGL) syndrome (SDHD/B and C genes). It has been reported that 24% of apparently sporadic PCCs patients harbor germline mutations in these PCC-causing genes. We investigated the contribution of the inherited PCC-causing genes in a partly retrospectively and partly prospectively obtained series of 213 apparently sporadic PCCs. Mutation analysis was performed for RET (56 cases), VHL (136 cases), and SDHD (126 cases) and SDHB (47 cases). No germline RET mutations, six (4.4%) germline VHL mutations, two (1.5%) germline SDHD mutations, and one germline (1.6%) SDHB mutation were found. In total we found germline mutations in about 7.5% of the investigated apparently sporadic PCCs. Although 7.5% germline mutations in a series of apparently sporadic PCCs are far less than the more than 20% reported in the literature, the figure is significant enough to consider germline mutation testing for each patient with PCC.

Sporadic human renal tumors display frequent allelic imbalances and novel mutations of the HRPT2 gene

Inactivation of the HRPT2 gene encoding parafibromin was recently linked to the familial hyperparathyroidism-jaw tumor syndrome. Patients with this syndrome carry an increased risk of parathyroid and renal tumors. To determine the relevance of HRPT2 for sporadic renal tumors, clear cell, papillary and chromophobe renal cell carcinomas as well as oncocytomas and Wilms tumors were analysed for HRPT2 gene alterations. Loss of heterozygosity (LOH) of HRPT2 was found in seven of 56 (12.5%) clear cell, three of 14 (21%) papillary, six of 10 (60%) chromophobe renal cell carcinomas, three of eight (38%) oncocytomas and four of 10 (40%) Wilms tumors. In addition, two novel HRPT2 point mutations, causing K34Q and R292K changes in parafibromin, were detected in one clear cell carcinoma and one Wilms tumor, respectively. These tumors displayed LOH of the remaining wild-type allele, but interestingly no von Hippel-Lindau (VHL) mutation. Functional analysis revealed that the K34Q mutant species of parafibromin is, unlike wild-type protein, defective in suppressing cyclin D1 expression in vivo. Taken together, these results suggest that renal cancer-associated mutations in parafibromin occur in the absence of VHL mutation, which in turn may contribute to constitutively elevated cyclin D1 expression and abnormal cell proliferation.

TNM staging of foregut (neuro)endocrine tumors: a consensus proposal including a grading system

The need for standards in the management of patients with endocrine tumors of the digestive system prompted the European Neuroendocrine Tumor Society (ENETS) to organize a first Consensus Conference, which was held in Frascati (Rome) and was based on the recently published ENETS guidelines on the diagnosis and treatment of digestive neuroendocrine tumors (NET). Here, we report the tumor–node–metastasis proposal for foregut NETs of the stomach, duodenum, and pancreas that was designed, discussed, and consensually approved at this conference. In addition, we report the proposal for a working formulation for the grading of digestive NETs based on mitotic count and Ki-67 index. This proposal, which needs to be validated, is meant to help clinicians in the stratification, treatment, and follow-up of patients.

IGFII and MIB1 immunohistochemistry is helpful for the differentiation of benign from malignant adrenocortical tumours

AIMS

The differentiation of adrenocortical carcinomas from adenomas may be difficult based on morphology alone. Differential expression of insulin-like growth factor (IGF) II and cyclin-dependent kinase (CDK) 4 has recently been described in these tumours. The aim of this study was to investigate the diagnostic usefulness of these markers immunohistochemically.

METHODS AND RESULTS

We examined 22 benign and 17 malignant adrenocortical tumours and compared IGFII and CDK4 expression with known immunohistochemical as well as morphological criteria of malignancy. Thirteen of 17 carcinomas showed immunohistochemical reactivity for IGFII, whereas all adenomas but one were negative. Intense CDK4 expression was detected in 11 of 17 carcinomas but was present in only three of 22 adenomas. The MIB1 index was >5% in 14 of 16 carcinomas and was <5% in all adenomas but one. The combination of IGFII immunohistochemistry with MIB1 index led to high sensitivity and specificity in detecting adrenocortical carcinomas.

CONCLUSIONS

IGFII and MIB1 are helpful immunohistochemical markers to predict malignancy in adrenocortical neoplasms. These markers can be used in addition to clinical, gross and morphological features to establish a diagnosis in difficult cases.

PTEN gene loss, but not mutation, in benign and malignant phaeochromocytomas

Mutations of the 'phosphatase and tensin homologue deleted on chromosome 10' (PTEN/MMAC1) gene have been associated with a variety of human cancers, including prostate cancer, glioblastoma, and melanoma. The gene is thought to be one of the most frequently mutated tumour suppressor genes and inactivation of PTEN is associated with disease progression and angiogenesis. High vascularization and resistance to chemo- and radio-therapy are two well-established features of phaeochromocytomas (PCCs). Furthermore, benign and malignant PCCs are found in several PTEN knockout mouse models. This study therefore evaluated whether inactivation of PTEN may be involved in the tumourigenesis of PCC in man and whether PTEN abnormalities may help to define the malignant potential of these tumours. Tumour and germline DNA was analysed from 31 patients with apparently sporadic PCC, including 14 clinically benign and 17 malignant tumours, for loss of the PTEN gene locus, mutations in the PTEN gene, and for PTEN protein expression by immunohistochemistry. Loss of heterozygosity (LOH) analysis showed loss of PTEN in four malignant tumours (40%) and in one benign tumour (14%). However, no mutations of PTEN were observed. Immunohistochemistry showed no correlation with clinical behaviour and/or LOH status. The results indicate that inactivation of the PTEN/MMAC1 gene may play a minor role in the development of malignant phaeochromocytomas.

A selective COX-2 inhibitor suppresses chronic pancreatitis in an animal model (WBN/Kob rats): significant reduction of macrophage infiltration and fibrosis

INTRODUCTION

Therapeutic strategies to treat chronic pancreatitis (CP) are very limited. Other chronic inflammatory diseases can be successfully suppressed by selective cyclooxygenase 2 (COX-2) inhibitors. As COX-2 is elevated in CP, we attempted to inhibit COX-2 activity in an animal model of CP (WBN/Kob rat). We then analysed the effect of COX-2 inhibition on macrophages, important mediators of chronic inflammation.

METHODS

Male WBN/Kob rats were continuously fed the COX-2 inhibitor rofecoxib, starting at the age of seven weeks. Animals were sacrificed 2, 5, 9, 17, 29, 41, and 47 weeks later. In some animals, treatment was discontinued after 17 weeks, and animals were observed for another 24 weeks.

RESULTS

Compared with the spontaneous development of inflammatory injury and fibrosis in WBN/Kob control rats, animals treated with rofecoxib exhibited a significant reduction and delay (p<0.0001) in inflammation. Collagen and transforming growth factor beta synthesis were significantly reduced. Similarly, prostaglandin E(2) levels were markedly lower, indicating strong inhibition of COX-2 activity (p<0.003). If treatment was discontinued at 24 weeks of age, all parameters of inflammation strongly increased comparable with that in untreated rats. The correlation of initial infiltration with subsequent fibrosis led us to determine the effect of rofecoxib on macrophage migration. In chemotaxis experiments, macrophages became insensitive to the chemoattractant fMLP in the presence of rofecoxib.

CONCLUSION

In the WBN/Kob rat, chronic inflammatory changes and subsequent fibrosis can be inhibited by rofecoxib. Initial events include infiltration of macrophages. Cell culture experiments indicate that migration of macrophages is COX-2 dependent.

Rare allelic imbalances, but no mutations of the PRDX1 gene in human hepatocellular carcinomas

Allelic losses on chromosome 1p are frequent in hepatocellular carcinoma (HCC), suggesting the presence of a tumour suppressor gene in this region. The gene for peroxiredoxin 1 (PRDX1), an antioxidant enzyme, has been mapped to 1p34.1. Mice lacking PRDX1 develop HCC with high frequency. Because oxidative stress has been implicated in the pathogenesis of HCC, this study was designed to determine whether the PRDX1 gene is mutated in human HCC using loss of heterozygosity (LOH) analysis, polymerase chain reaction/denaturing gradient gel electrophoresis, and DNA sequencing. LOH of at least one of four microsatellite markers within 0.8 Mb of the PRDX1 gene was seen in three of 34 informative HCCs, but no mutations or polymorphisms in the translated exons 2-6 of the PRDX1 gene were found. These results suggest that genetic alterations of the PRDX1 locus are rare events in human HCC, indicating that other genes on chromosome 1p contribute to liver carcinogenesis.

No mutations but an increased frequency of SDHx polymorphisms in patients with sporadic and familial medullary thyroid carcinoma

Germline mutations of the three succinate dehydrogenase subunits SDHB, SDHC and SDHD have recently been associated with familial pheochromocytoma and paraganglioma. Several reasons make these genes candidate tumor suppressor genes for medullary thyroid carcinoma (MTC): (1) SDHB lies on chromosome 1p, the region known to be deleted most frequently in MTC, (2) MTCs develop from neural crest-derived cells, as do pheochromocytomas and paragangliomas and (3) patients with germline mutations of the Ret-protooncogene develop MTCs as well as pheochromocytomas, indicating a relationship of these tumors on a genetic level. Therefore, we attempted to determine whether the tumor suppressor genes SDHB, SDHC and SDHD are involved in sporadic and familial MTC. Somatic mutations of the SDH subunits were absent in all 35 investigated MTCs. Loss of heterozygosity was found in 27% (SDHB) and 4% (SDHD) respectively. While the frequency of non-coding, intronic polymorphisms did not differ in MTC patients compared with a control population, an accumulation of amino-acid coding polymorphisms (S163P in SDHB as well as G12S and H50R in SDHD) was found among MTC patients especially patients with familial tumors, suggesting a functional connection of coding SDH polymorphisms to activating Ret mutations.

Die kondyläre Metastasierung

BACKGROUND

Metastases in the mandibular condyle are rare. A survey of the literature showed that only 23 of 69 selected cases qualified under the criteria of Meyer and Shklar.

REPORT OF A CASE

A 48-year-old white male suffering from a previously operated lung carcinoma was referred due to pain and discomfort in the left TMJ. A solitary condylar metastasis of the mandible was revealed. Because of diffuse tumorous infiltration into periarticular tissue, irradiation treatment was performed. During the long-term follow-up growth of additional skeletal metastases occurred.

DISCUSSION

The course of condylar metastases in general is similar to other metastases involving the jaw. Breast cancer as the primary tumor is most frequent, followed by lung cancer. There are no specific clinical or radiological parameters leading to diagnosis. The clinician should take a potential metastasis into account when dealing with TMJ complaints, radiological oddities, and medical history of malignant tumors. For proper treatment planning, diagnosis should be based on histology. Since the diagnosis of metastasis is usually made at an advanced stage of disease, therapy will be mainly intended as palliative.