Long-Term Safety of In Utero Exposure to Anti-TNFα Drugs for the Treatment of Inflammatory Bowel Disease: Results from the Multicenter European TEDDY Study.

OBJECTIVES: The long-term safety of exposure to anti-tumor necrosis factor (anti-TNFα) drugs during pregnancy has received little attention. We aimed to compare the relative risk of severe infections in children of mothers with inflammatory bowel disease (IBD) who were exposed to anti-TNFα drugs in utero with that of children who were not exposed to the drugs. METHODS: Retrospective multicenter cohort study. Exposed cohort: children from mothers with IBD receiving anti-TNFα medication (with or without thiopurines) at any time during pregnancy or during the 3 months before conception. Non-exposed cohort: children from mothers with IBD not treated with anti-TNFα agents or thiopurines at any time during pregnancy or the 3 months before conception. The cumulative incidence of severe infections after birth was estimated using Kaplan-Meier curves, which were compared using the log-rank test. Cox-regression analysis was performed to identify potential predictive factors for severe infections in the offspring. RESULTS: The study population comprised 841 children, of whom 388 (46%) had been exposed to anti-TNFα agents. Median follow-up after delivery was 47 months in the exposed group and 68 months in the non-exposed group. Both univariate and multivariate analysis showed the incidence rate of severe infections to be similar in non-exposed and exposed children (1.6% vs. 2.8% per person-year, hazard ratio 1.2 (95% confidence interval 0.8-1.8)). In the multivariate analysis, preterm delivery was the only variable associated with a higher risk of severe infection (2.5% (1.5-4.3)). CONCLUSIONS: In utero exposure to anti-TNFα drugs does not seem to be associated with increased short-term or long-term risk of severe infections in children.

Characterization of ß-cell plasticity mechanisms induced in mice by a transient source of exogenous insulin.

ß-Cell plasticity governs the adjustment of ß-cell mass and function to ensure normoglycemia. The study of how ß-cell mass is controlled and the identification of alternative sources of ß-cells are active fields of research. ß-Cell plasticity has been implicated in numerous physiological and pathological conditions. We developed a mice model in which we induced major ß-cell mass atrophy by implanting insulin pellets (IPI) for 7 or 10 days. The implants were then removed (IPR) to observe the timing and characteristics of ß-cell regeneration in parallel to changes in glycemia. Following IPR, the endocrine mass was reduced by 60% at day 7 and by 75% at day 10, and transient hyperglycemia was observed, which resolved within 1 wk. Five days after IPR, enhanced ß-cell proliferation and an increased frequency of small islets were observed in 7-day IPI mice. ß-Cell mass was fully restored after an additional 2 days. For the 10-day IPI group, ß-cell and endocrine mass were no longer significantly different from those of the control group at 2 wk post-IPR. Furthermore, real-time quantitative PCR analysis of endocrine structures isolated by laser capture microdissection indicated sequentially enhanced expression of the pancreatic transcription factors ß(2)/NeuroD and Pdx-1 post-IPR. Thus, our data suggest this mouse model of ß-cell plasticity not only relies on replication but also involves enhanced cell differentiation plasticity.

Novel histologic scoring system for long-term allograft fibrosis after liver transplantation in children.

The existing systems for scoring fibrosis were not developed to evaluate transplanted livers. Our aim was to design and validate a novel fibrosis scoring system specifically adapted to assess liver allograft fibrosis (LAF). Clinical data, histology, transient elastography (TE) and AST/platelet ratio index (APRI) were reviewed in 38 pediatric liver transplant (LT) recipients. Protocol liver biopsies performed at 6 months and 7 years post-LT were reviewed by three pathologists who assessed LAF using the METAVIR and Ishak systems. LAF was also scored separately in portal (0-3), sinusoidal (0-3) and centrolobular areas (0-3). Scoring evaluations were correlated with fibrosis quantification using morphometry, and also with TE and APRI. Statistical correlations between morphometry and METAVIR were 0.571 (p < 0.000) and 0.566 (p < 0.000) for the Ishak system. The novel score (0-9) for separate assessment of portal, sinusoidal and centrolobular fibrosis showed a better correlation with morphometry (0.731; p < 0.000) and high intra-/interobserver agreement (0.966; p < 0.000 and 0.794; p < 0.000, respectively). No correlation was found between TE or APRI and morphometry or the three histologic scores. In conclusion, this novel semiquantitative fibrosis scoring system seems to more accurately reflect LAF than the existing scoring system and may become a practical tool for staging fibrosis in LT.

Elevated carbohydrate antigen 19-9 following Helicobacter suis gastritis and normalisation after eradication: first case report and review of the literature.

Carbohydrate antigen 19-9 (CA 19-9) is a biological marker used to diagnose and monitor the progression of various cancers. Elevated CA 19-9 has also been sporadically observed in Helicobacter pylori infected patients. Similar to H. pylori, animalhosted non-H. pylori Helicobacter (NHPH) species can induce gastroduodenal lesions in humans. We report the first case of CA 19-9 elevation related to H. suis gastritis and its normalisation after eradication. A CA 19-9 screening prescribed as part of a regular check up by the general practitioner was found elevated in a 68-year-old man presenting chronic dyspeptic symptoms. Medical investigations were negative for presence of neoplasia or biliary obstruction. Upper gastrointestinal endoscopy confirmed the presence of chronic gastritis and H. suis was identified in gastric biopsies. The standard treatment for H. pylori successfully eradicated H. suis with normalisation of CA 19-9 levels. In addition to H. pylori, infection with NHPH species should be considered as an additional cause of elevated CA19-9.

Pancreatic alpha cell mass in European subjects with type 2 diabetes.

AIMS/HYPOTHESIS: Type 2 diabetes is a bi-hormonal disease characterised by relative hypoinsulinaemia and hyperglucagonaemia with elevated blood glucose levels. Besides pancreatic beta cell defects, a low number of beta cells (low beta cell mass) may contribute to the insufficient secretion of insulin. In this study our aim was to determine whether the alpha cell mass is also altered. METHODS: Using a point counting method, we measured the ratio of alpha to beta cell areas in pancreas samples obtained at autopsy from 50 type 2 diabetic subjects, whose beta cell mass had previously been found to be 36% lower than that of 52 non-diabetic subjects. RESULTS: The topography of alpha and beta cells was similar in both groups: many alpha cells were localised in the centre of the islets and the ratio of alpha/beta cell areas increased with islet size. The average ratio was significantly higher in type 2 diabetic subjects (0.72) than in non-diabetic subjects (0.42), with, however, a large overlap between the two groups. In contrast, the alpha cell mass was virtually identical in type 2 diabetic subjects (366 mg) and non-diabetic subjects (342 mg), and was not influenced by sex, BMI or type of diabetes treatment. CONCLUSIONS: The higher proportion of alpha to beta cells in the islets of some type 2 diabetic subjects is due to a decrease in beta cell number rather than an increase in alpha cell number. This imbalance may contribute to alterations in the normal inhibitory influence exerted by beta cells on alpha cells, and lead to the relative hyperglucagonaemia observed in type 2 diabetes.

ABCC8 and KCNJ11 molecular spectrum of 109 patients with diazoxide-unresponsive congenital hyperinsulinism.

BACKGROUND: Congenital hyperinsulinism (CHI) is characterised by an over secretion of insulin by the pancreatic ß-cells. This condition is mostly caused by mutations in ABCC8 or KCNJ11 genes encoding the SUR1 and KIR6.2 subunits of the ATP-sensitive potassium (K(ATP)) channel. CHI patients are classified according to their responsiveness to diazoxide and to their histopathological diagnosis (either focal, diffuse or atypical forms). Here, we raise the benefits/limits of the genetic diagnosis in the clinical management of CHI patients. METHODS: ABCC8/KCNJ11 mutational spectrum was established in 109 diazoxide-unresponsive CHI patients for whom an appropriate clinical management is essential to prevent brain damage. Relationships between genotype and radiopathological diagnosis were analysed. RESULTS: ABCC8 or KCNJ11 defects were found in 82% of the CHI cases. All patients with a focal form were associated with a single K(ATP) channel molecular event. In contrast, patients with diffuse forms were genetically more heterogeneous: 47% were associated with recessively inherited mutations, 34% carried a single heterozygous mutation and 19% had no mutation. There appeared to be a predominance of paternally inherited mutations in patients diagnosed with a diffuse form and carrying a sole K(ATP) channel mutation. CONCLUSIONS: The identification of recessively inherited mutations related to severe and diffuse forms of CHI provides an informative genetic diagnosis and allows prenatal diagnosis. In contrast, in patients carrying a single K(ATP) channel mutation, genetic analysis should be confronted with the PET imaging to categorise patients as focal or diffuse forms in order to get the appropriate therapeutic management.

Inflammatory Bowel Disease Management During the COVID-19 Outbreak: The Ten Do's and Don'ts from the ECCO-COVID Taskforce.

Our knowledge of COVID-19 is changing and evolving rapidly, with novel insights and recommendations, almost on a daily basis. It behooves the medical community to provide updated information on a regular basis, on best practice to facilitate optimal care of infected patients and on appropriate advice for the general population. This is particularly important in the case of patients with chronic conditions, such as inflammatory bowel disease [IBD]. In this review, we have compiled existing evidence on the impact of COVID-19 in IBD patients and provide guidance on the most appropriate care to adopt during the pandemic. Our review highlights that IBD, per se, is not a risk factor for COVID-19. However, all IBD patients with symptoms should be tested for SARS-CoV-2 and the procedures for disease management should be carefully adapted: [i] in SARS-CoV-2-positive IBD patients, medical treatments should be re-evaluated [with a particular focus on corticosteroids] always with the purpose of treating active disease and maintaining remission; [ii] non-urgent surgeries and endoscopic procedures should be postponed for all patients; [iii] online consultancy should be implemented; and [iv] hospitalization and surgery should be limited to life-threatening situations.

Pancreatic beta-cell mass in European subjects with type 2 diabetes.

Decreases in both beta-cell function and number can contribute to insulin deficiency in type 2 diabetes. Here, we quantified the beta-cell mass in pancreas obtained at autopsy of 57 type 2 diabetic (T2D) and 52 non-diabetic subjects of European origin. Sections from the body and tail were immunostained for insulin. The beta-cell mass was calculated from the volume density of beta-cells (measured by point-counting methods) and the weight of the pancreas. The pancreatic insulin concentration was measured in some of the subjects. beta-cell mass increased only slightly with body mass index (BMI). After matching for BMI, the beta-cell mass was 41% (BMI < 25) and 38% (BMI 26-40) lower in T2D compared with non-diabetic subjects, and neither gender nor type of treatment influenced these differences. beta-cell mass did not correlate with age at diagnosis but decreased with duration of clinical diabetes (24 and 54% lower than controls in subjects with <5 and >15 years of overt diabetes respectively). Pancreatic insulin concentration was 30% lower in patients. In conclusion, the average beta-cell mass is about 39% lower in T2D subjects compared with matched controls. Its decrease with duration of the disease could be a consequence of diabetes that, with further impairment of insulin secretion, contributes to the progressive deterioration of glucose homeostasis. We do not believe that the small difference in beta-cell mass observed within 5 years of onset could cause diabetes in the absence of beta-cell dysfunction.

Dominantly inherited hyperinsulinism caused by a mutation in the sulfonylurea receptor type 1.

ATP-sensitive potassium channels play a major role in linking metabolic signals to the exocytosis of insulin in the pancreatic beta cell. These channels consist of two types of protein subunit: the sulfonylurea receptor SUR1 and the inward rectifying potassium channel Kir6.2. Mutations in the genes encoding these proteins are the most common cause of congenital hyperinsulinism (CHI). Since 1973, we have followed up 38 pediatric CHI patients in Finland. We reported previously that a loss-of-function mutation in SUR1 (V187D) is responsible for CHI of the most severe cases. We have now identified a missense mutation, E1506K, within the second nucleotide binding fold of SUR1, found heterozygous in seven related patients with CHI and in their mothers. All patients have a mild form of CHI that usually can be managed by long-term diazoxide treatment. This clinical finding is in agreement with the results of heterologous coexpression studies of recombinant Kir6.2 and SUR1 carrying the E1506K mutation. Mutant K(ATP) channels were insensitive to metabolic inhibition, but a partial response to diazoxide was retained. Five of the six mothers, two of whom suffered from hypoglycemia in infancy, have developed gestational or permanent diabetes. Linkage and haplotype analysis supported a dominant pattern of inheritance in a large pedigree. In conclusion, we describe the first dominantly inherited SUR1 mutation that causes CHI in early life and predisposes to later insulin deficiency.

Paternal mutation of the sulfonylurea receptor (SUR1) gene and maternal loss of 11p15 imprinted genes lead to persistent hyperinsulinism in focal adenomatous hyperplasia.

Congenital hyperinsulinism, or persistent hyperinsulinemic hypoglycemia of infancy (PHHI), is a glucose metabolism disorder characterized by unregulated secretion of insulin and profound hypoglycemia. From a morphological standpoint, there are two types of histopathological lesions, a focal adenomatous hyperplasia of islet cells of the pancreas in approximately 30% of operated sporadic cases, and a diffuse form. In sporadic focal forms, specific losses of maternal alleles (LOH) of the imprinted chromosomal region 11p15, restricted to the hyperplastic area of the pancreas, were observed. Similar mechanisms are observed in embryonal tumors and in the Beckwith-Wiedemann syndrome (BWS), also associated with neonatal but transient hyperinsulinism. However, this region also contains the sulfonylurea receptor (SUR1) gene and the inward rectifying potassium channel subunit (KIR6.2) gene, involved in recessive familial forms of PHHI, but not known to be imprinted. Although the parental bias in loss of maternal alleles did not argue in favor of their direct involvement, the LOH may also unmask a recessive mutation leading to persistent hyperinsulinism. We now report somatic reduction to hemizygosity or homozygosity of a paternal SUR1 constitutional heterozygous mutation in four patients with a focal form of PHHI. Thus, this somatic event which leads both to beta cell proliferation and to hyperinsulinism can be considered as the somatic equivalent, restricted to a microscopic focal lesion, of constitutional uniparental disomy associated with unmasking of a heterozygous parental mutation leading to a somatic recessive disorder.

Somatic deletion of the imprinted 11p15 region in sporadic persistent hyperinsulinemic hypoglycemia of infancy is specific of focal adenomatous hyperplasia and endorses partial pancreatectomy.

Sporadic persistent hyperinsulinemic hypoglycemia of infancy (PHHI) or nesidioblastosis is a heterogeneous disorder characterized by profound hypoglycemia due to inappropriate hypersecretion of insulin. An important diagnostic goal is to distinguish patients with a focal hyperplasia of islet cells of the pancreas (FoPHHI) from those with a diffuse abnormality of islets (DiPHHI) because management strategies differ significantly. 16 infants with sporadic PHHI resistant to diazoxide and who underwent pancreatectomy were investigated. Selective pancreatic venous sampling coupled with peroperative surgical examination and analysis of extemporaneous frozen sections allowed us to identify 10 cases with FoPHHI and 6 cases with DiPHHI. We show here that in cases of FoPHHI, but not those of DiPHHI, there was specific loss of maternal alleles of the imprinted chromosome region 11p15 in cells of the hyperplastic area of the pancreas but not in normal pancreatic cells. This somatic event is consistent with a proliferative monoclonal lesion. It involves disruption of the balance between monoallelic expression of several maternally and paternally expressed genes. Thus, we provide the first molecular explanation of the heterogeneity of sporadic forms of PHHI such that it is possible to perform only partial pancreatectomy, limited to the focal somatic lesion, so as to avoid iatrogenic diabetes in patients with focal adenomatous hyperplasia.

Congenital hyperinsulinism and mosaic abnormalities of the ploidy.

BACKGROUND: Congenital hyperinsulinism and Beckwith-Wiedemann syndrome both lead to beta islet hyperplasia and neonatal hypoglycaemia. They may be related to complex genetic/epigenetic abnormalities of the imprinted 11p15 region. The possibility of common pathophysiological determinants has not been thoroughly investigated. OBJECTIVE: To report abnormalities of the ploidy in two unrelated patients with congenital hyperinsulinism. METHODS: Two patients with severe congenital hyperinsulinism, one overlapping with Beckwith-Wiedemann syndrome, had pancreatic histology, ex vivo potassium channel electrophysiological studies, and mutation detection of the encoding genes. The parental genetic contribution was explored using genome-wide polymorphism, fluorescent in situ hybridisation (FISH), and blood group typing studies. RESULTS: Histological findings diverged from those described in focal congenital hyperinsulinism or Beckwith-Wiedemann syndrome. No potassium channel dysfunction and no mutation of its encoding genes (SUR1, KIR6.2) were detected. In patient 1 with congenital hyperinsulinism and Beckwith-Wiedemann syndrome, paternal isodisomy for the whole haploid set was homogeneous in the pancreatic lesion, and mosaic in the leucocytes and skin fibroblasts (hemihypertrophic segment). Blood group typing confirmed the presence of two erythroid populations (bi-parental v paternal only contribution). Patient 2 had two pancreatic lesions, both revealing triploidy with paternal heterodisomy. Karyotype and FISH analyses done on the fibroblasts and leucocytes of both patients were unremarkable (diploidy). CONCLUSIONS: Diploid (biparental/paternal-only) mosaicism and diploid/triploid mosaicism were present in two distinct patients with congenital hyperinsulinism. These chromosomal abnormalities led to paternal disomy for the whole haploid set in pancreatic lesions (with isodisomy or heterodisomy), thereby extending the range and complexity of the mechanisms underlying congenital hyperinsulinism, associated or not with Beckwith-Wiedemann syndrome.

Propylthiouracyl-induced severe liver toxicity: an indication for alanine aminotransferase monitoring?

Propylthiouracyl (PTU)-related liver toxicity is likely to occur in about 1% of treated patients. In case of acute or subacute hepatitis, liver failure may occur in about one third. We report two further cases of PTU-induced subacute hepatitis, in whom the delay between occurrence of liver damage after the initiation of treatment, the underestimation of its severity and the delayed withdrawal of the drug were all likely responsible for liver failure. The high incidence of liver toxicity related to PTU, its potential severity and delayed occurrence after initiation of treatment are in favor of monthly alanine aminotransferase monitoring, at least during the first six months of therapy.

Cancer Immunotherapy with Anti-CTLA-4 Monoclonal Antibodies Induces an Inflammatory Bowel Disease.

BACKGROUND: Therapeutic monoclonal anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibodies are associated with immune-mediated enterocolitis. The aim of this study was to provide a detailed description of this entity. METHODS: We included patients with endoscopic signs of inflammation after anti-CTLA-4 infusions for cancer treatment. Other causes of enterocolitis were excluded. Clinical, biological and endoscopic data were recorded. A single pathologist reviewed endoscopic biopsies and colectomy specimens from 27 patients. Patients with and without enterocolitis after ipilimumab-treated melanoma were compared, to identify clinical factors associated with enterocolitis. RESULTS: Thirty-nine patients with anti-CTLA-4 enterocolitis were included (ipilimumab n = 37; tremelimumab n = 2). The most frequent symptom was diarrhoea. Ten patients had extra-intestinal manifestations. Most colonoscopies showed ulcerations involving the rectum and sigmoid, 66% of patients had extensive colitis, 55% had patchy distribution and 20% had ileal inflammation. Endoscopic colonic biopsies showed acute colitis in most patients, while half of the patients had chronic duodenitis. Thirty-five patients received steroids that led to complete clinical remission in 13 patients (37%). Twelve patients required infliximab, of whom 10 (83%) responded. Six patients underwent colectomy (perforation n = 5; toxic megacolon n = 1); one of them died postoperatively. Four patients had a persistent enterocolitis at follow-up colonoscopy. Patients with enterocolitis were more frequently prescribed NSAIDs compared with patients without enterocolitis (31 vs 5%, p = 0.003). CONCLUSIONS: Ipilimumab and tremelimumab may induce a severe and extensive form of inflammatory bowel disease. Rapid escalation to infliximab should be advocated in patients who do not respond to steroids. Patients treated with anti-CTLA-4 should be advised to avoid NSAIDs.

Human type 2 diabetes: morphological evidence for abnormal beta-cell function.

The exact nature of the beta-cell defect in type 2 diabetic patients is still unclear. beta-Cell mass reduction has been reported but remains controversial. A preliminary study of a large series of patients has demonstrated that in most, the beta-cell defect is not related to a decreased beta-cell mass. Amyloid deposits are observed in the islets of some type 2 diabetic patients but also in normoglycemic subjects. Because it has been claimed that these deposits interfere with beta-cell function, we evaluated in situ the effect of insular amyloid deposits on beta-cell transcription and translation. Pancreases were obtained at autopsy from 28 normoglycemic patients and 41 type 2 diabetic patients. Staining with hemaluneosin and Congo red was used to analyze the general features of the islets and the presence of amyloid deposits, respectively. Immunohistochemistry for proinsulin was performed with an antibody recognizing the junction between B-chain and C-peptide, thus specifically labeling the Golgi area where proinsulin is produced. In seven patients, we evaluated insulin gene transcription by in situ hybridization of proinsulin mRNA combined with Congo red staining, and we evaluated insulin storage by double immunostaining for insulin and amylin. In many type 2 diabetic patients, the islets appeared entirely normal. Amyloid deposits were found in 57% of diabetic subjects and 33% of normoglycemic age-matched control subjects. The percentage of amyloid-infiltrated islets varied from 0.4 to 74%. beta-Cells from amyloid-containing islets still had specific Golgi proinsulin labeling. In obese type 2 diabetic patients, the number of beta-cells with abnormal expression of proinsulin in the whole cytoplasm was significantly higher than in normoglycemic control subjects. Proinsulin mRNA was significantly reduced in islets with amyloid deposits when compared with amyloid-free islets, but the mean reduction did not exceed 16%. Insulin was still present in the beta-cells of amyloid-containing islets, and its amount, estimated by measurement of the insulin-labeling optical density, was not statistically different from that in amyloid-free islets. In conclusion, even in amyloid-containing islets, beta-cells maintain active insulin transcription and translation and normal insulin storage. Taking into account that in most cases only a small proportion of islets are infiltrated by amyloid, the limited reduction in proinsulin mRNA is unlikely to play a major role in the pathogenesis of diabetes.

[Congenital hyperinsulinism of infancy: surgical treatment in 60 cases of focal form]. / Hyperinsulinisme persistant du nouveau-né et du nourrisson: traitement chirurgical des lésions pancréatiques focales dans 60 cas.

Congenital hyperinsulinism of infancy is a severe disease that leads to important brain damage. Two different forms of the disease have been identified by pathologists: a diffuse and a focal form. A specific genetic anomaly identified in focal forms has never been described in diffuse ones. However, for most of authors, failure of medical treatment results in near-total pancreatectomy in all cases, which ends in diabetus. The aim of this retrospective study was to assess the results of elective partial pancreatectomy performed in 60 cases of focal form of hyperinsulinism over the last 18 years. Fifty-eight patients were cured with euglycemia at both fasting and hyperglycaemic tests without insulin-dependent diabetes mellitus. One patient is still in hypoglycaemia from unrecognized lesion; insulin-dependent diabetes mellitus occurred in one case nine years after surgery (a near-total pancreatectomy has been performed because of unknown focal form, in 1985).

The pancreatic polypeptide cells in the human pancreas: the effects of age and diabetes.

Pancreases from insulin-dependent diabetics (IDDM), noninsulin-dependent diabetics (NIDDM), and nondiabetic subjects were analyzed by stereological and morphometrical methods in order to determine the weight of the lobe rich in pancreatic polypeptide (PP) cells in relation to the total weight of the pancreas and the volume density of PP cells in both parts of the gland, those rich and poor in PP cells. In control subjects, neither the relative weight of the lobe rich in PP cells, nor the volume density of PP cells varied significantly with aging. In IDDM and NIDDM, the volume density of PP cells was similar to that observed in control subjects. The total weight of the pancreas was markedly decreased in IDD because of an almost selective atrophy of the lobe poor in PP cells; the relative weight of the lobe rich in PP cells was thus much higher than that in control subjects. A less marked atrophy, restricted to the lobe poor in PP cells, was also observed in NIDDM. It is suggested that PP may exert a local trophic role which protects the lobe of the pancreas rich in PP cells from atrophy in diabetic patients. The results further show that the elevated levels of PP in the plasma of elderly or diabetic subjects cannot be ascribed to a hyperplasia of PP cells.

Neonatal hyperinsulinemic hypoglycemia: heterogeneity of the syndrome and keys for differential diagnosis.

The two major forms of infantile persistent hyperinsulinemic hypoglycemia require different treatments, but are difficult to differentiate during surgery. Indeed, one is characterized by focal adenomatous hyperplasia often macroscopically invisible, whereas the other consists of a diffuse, but discreet, beta-cell abnormality. We evaluated, in a large series of persistent hyperinsulinemic hypoglycemia, the reliability of two criteria in differentiating these two forms: the mean beta-cell nuclear radius (MNR) and the beta-cell nuclear crowding, i.e. the number of nuclei per 1000 micron 2 beta-cell (BCNC). The values of the largest MNR and of BCNC in cases bearing a focal lesion (respectively, 3.27 microns +/- 0.25 and 14.62 +/- 1.78) were significantly different from those in the diffuse pathology (4.25 microns +/- 0.43 and 10.00 +/- 1.55). Setting the threshold value of MNR at 3.70 microns and that of BCNC at 12.00 enabled correct classification of 90.9% of the diffuse and 100% of the focal forms. beta-Cell nuclear analysis can thus contribute to a subclassification of the syndrome, not allowed by clinical or biological data. If performed during surgery it could help in determining the extent of pancreatectomy necessary to cure the patient, as the diffuse form, with abnormal nuclei in the whole pancreas, requires subtotal to near-total pancreatectomy, whereas the focal form, devoid of abnormal insular beta-cell nuclei, can be cured by partial pancreatectomy.