Distribution of edin in Staphylococcus aureus isolated from diabetic foot ulcers.

Staphylococcus aureus is both a common colonizer of human skin and the most frequently isolated pathogen in diabetes foot infections (DFIs). The spread of DFI to soft tissue and bony structures is a major causal factor for lower-limb amputation. It is therefore of great importance to differentiate colonizing from infecting strains of S. aureus. Epidermal cell differentiation inhibitors known as EDIN and EDIN-like factors, a group of toxins targeting RhoA master regulator of the actin cytoskeleton, may confer virulence properties on S. aureus. In this study, for the first time, analysis of S. aureus strains, recovered in DFIs at an initial stage and during the follow-up, showed that 71.4% of edin-positive strains were associated with moderate-to-severe infections (grades 3 and 4 of the IDSA/IWGDF classification) compared with 28.6% of edin-positive strains associated with low-grade infections. Most of these strains were edin-B positive (86.7%) and belonged to CC25/28-MSSA (n = 10). One edin-B-positive ST152-MSSA strain was negative for the two highly prevalent predictive markers of infecting strains (lukDE and hlgv). Collectively, this points towards the edin-B encoding gene as a bonafide subsidiary predictive risk marker of DFI.

Spontaneous hypoglycaemia in the presence of both anti-insulin antibody and anti-insulin receptor antibody.

Beside insulinoma, alternative causes of hyperinsulinaemic hypoglycaemia include the rare autoimmune syndrome related to spontaneous autoantibodies either to insulin or to insulin receptor. We describe a case of hypoglycaemia with high insulinemia in which insulinoma could not be evidenced. Surprisingly, we found in the patient's serum both insulin autoantibodies and insulin receptor autoantibodies. Available data eventually supported the predominant role of insulin autoantibodies rather than insulin receptor autoantibodies in the mechanism of hypoglycaemia of this patient. Insulin antibodies were present in high titre. Most of the insulin in serum was bound to the insulin antibodies and free insulin was slightly increased. HLA typing displayed DR4 haplotype, known to be strongly linked to the insulin autoimmune syndrome. The patient's serum was able to inhibit insulin binding to its receptor in a cultured cell line overexpressing insulin receptors both in experiments with native serum and with serum depleted from insulin antibodies. However, we could not demonstrate that the insulin receptor antibodies had insulin mimicking effect. We have no obvious explanation for the presence of these two antibodies in the same patient. Possible hypotheses might involve an idiotype-anti-idiotype mechanism or a poly-autoimmune disease.

[Clinical relevance of homocysteine monitoring in the diabetic patient]. / Faut-il doser l'homocystéine chez le patient diabétique?

Accelerated atherosclerosis is common in diabetes mellitus, although its extent is not always related to its strong association with classical cardiovascular risk factors. Diabetic patients, especially with type 2 diabetes, are prone to cardiovascular disease which is the leading cause of death in this population. Recent clinical studies among general population have shown that an even mild increase of homocysteinemia play an important role in the progression of atherosclerosis, either in coronary or peripheral arteries. An increasing amount of in vitro data is providing evidence that excess of homocysteine has a toxic effect on the arterial wall. This aminoacid thus appears to be not only a risk marker but also an emerging cardiovascular risk factor. The measurement of plasma homocysteine contributes to the identification, among the diabetic population, of patients at high cardio-vascular risk, with the aim of improving their global management. Moreover the addition of group B vitamins provides an easy and low-cost treatment to lower hyperhomocysteinemia.

Assessment of cardiac arrhythmic risk in diabetic patients using QT dispersion abnormalities.

The purpose of this study was to assess the abnormalities and prevalence of QT dispersion in 154 diabetic patients (DP) who underwent a standard 12-lead ECG. QT interval was measured from the beginning of the QRS complex until the T wave returned to baseline. Atrial fibrillation, pacemakers and the impossibility of measuring 6 QT intervals per ECG were reasons for exclusion from the study. Diabetic patients were compared with 104 sex- and age-matched controls (C): mean age 50.7 +/- 2.3 years (DP) vs 48.4 +/- 10.1 (C) (ns); diabetes duration: 11.6 +/- 7.9 years. Seventy-eight percent of DP were non-insulin-dependent. Mean QT duration was 0.383 +/- 0.031 s (DP) vs 0.381 +/- 0.026 (C) (ns); QT dispersion (difference between the longest and shortest QT interval measurement) 0.033 +/- 0.015 s (DP) vs 0.024 +/- 0.011 (C) (p < 0.001); and QT variability 3.003 +/- 1.23% (DP) vs 2.295 +/- 0.936 (C) (p < 0.001); with a standard deviation of 0.012 +/- 0.005 s (DP) vs 0.009 +/- 0.004 (C) (ns). QT dispersion indices (dispersion, variability) were significantly increased in DP, even for short diabetes duration. Future studies should focus on QT dispersion to assess the usefulness of such indices in detecting DP at high risk of sudden death and ventricular arrhythmias.

Apparent activities of 21-hydroxylase, 17alpha-hydroxylase and 17,20-lyase are impaired in adrenal incidentalomas.

OBJECTIVE: An increased response of 17-hydroxyprogesterone to ACTH stimulation has been observed in adrenal incidentaloma and linked to an impairment of either 21-hydroxylase or of 11beta-hydroxylase activity. To analyse this question further, we investigated the steroidogenic pathways in a series of 17 adrenal incidentalomas. DESIGN AND PATIENTS: 17 patients (7 women, 10 men; mean age, 62 +/- 12 years) with non-histologically analyzed adrenal incidentalomas were prospectively evaluated. METHODS: The following variables were investigated: 24-h urinary methanephrines and free cortisol excretion; plasma levels of ACTH and dehydroepiandrosterone; overnight dexamethasone suppression test; 1-24 ACTH stimulation test with measurement of: cortisol, 11-deoxycortisol, 17-hydroxyprogesterone, aldosterone, 11-deoxycorticosterone, progesterone, 17-hydroxypregnenolone, Delta4-androstenedione, dehydroepiandrosterone and 21-deoxycortisol. RESULTS: Discordant features of subclinical hypercorticism were noted in one case. No patient had dehydroepiandrosterone sulfate levels in the normal range for his or her age. Peak 17-hydroxyprogesterone and peak 21-deoxycortisol disclosed impairment of 21-hydroxylase in 11 and 10 cases respectively. An increased 11-deoxycortisol/cortisol ratio identified reduced activity of 11beta-hydroxylase in 11 patients. Eight patients displayed features of mild 17,20-lyase impairment, which was related to 21-hydroxylase dysfunction. Whereas only 2 patients showed no enzyme modification, 9 displayed alterations of at least two pathways. CONCLUSION: In our hands, a combination of enzyme dysfunction was frequently observed. Shared biochemical mechanisms could explain combined 17,20-lyase and 21-hydroxylase alterations, whereas coexistence of 21-hydroxylase (particularly when based on peak 21-deoxycortisol) and 11beta-hydroxylase is more puzzling.

[Macroprolactinemia, a variety of hyperprolactinemia. Apropos of 5 cases]. / Macroprolactinémie, une variété d'hyperprolactinémie. A propos de cinq observations.

Macroprolactinemia, due to increased circulating levels of large molecular weight forms of prolactin, results in elevated level of immuno-reactive prolactin. The big variants have only weak biological activity; thus macroprolactinemia appears as a case of hyperprolactinemia without clinical significance as demonstrated by the five patients described. The diagnosis is based upon chromatography which separates the hormone and its variants. This disorder produces a pitfall in the diagnostic evaluation of hyperprolactinemia.

Type 1 diabetes mellitus and homocyst(e)ine.

High Homocyst(e)ine levels (H) have been recently recognized as a risk factor for atherosclerosis. Patients with Diabetes Mellitus (DM) are prone to atherosclerosis. Therefore, this study was designed to search for the effect of DM on H and their relationship. Forty-one Type 1 diabetic subjects (DS, age 34.8 +/- 12 yr, DM duration: 10.7 +/- 11.1 yr) were compared to 40 age-matched control subject (CS, age 34.2 +/- 9.1 yr). H (measured by ion-exchange chromatography, units: mumol/l) and several parameters (creatininemia; triglycerides; total, HDL, LDL cholesterol; Lp(a); HbA1c; vitamins B9 and B12) were determined after an overnight fast. H were significantly (p = 0.0001) lower in DS (6.8 +/- 2.2) than in CS (9.5 +/- 2.9). This difference was still apparent in male and female subgroups compared to matched CS (p = 0.003 for each). No correlation was found between H and: lipids, vitamins, renal or retinal status. But H seemed to increase with age, especially in women (p = 0.03; r = 0.32). While there is, at this time, no explanation for the lower H observed in DS, it appears that H cannot directly account for accelerated atherosclerosis in DM. Nevertheless, it remains to be established if high, or even normal, H could identify a subgroup of DS at higher risk of precocious and severe atherosclerosis.

Mycobacterium avium intracellulare suppurative thyroiditis in a patient with Hashimoto's thyroiditis.

A case of suppurative thyroiditis occurring in a 72-year-old woman is reported. The clinical history of this woman, treated by tianeptine for mild exogenous affective disorder and by conventional insulin therapy for long-standing insulin-dependent diabetes, was remarkable for the pseudotumoral signs which led to the simultaneous diagnosis of hypothyroidism due to Hashimoto's thyroiditis and of mycobacterium avium intracellulare suppurative thyroiditis. To our knowledge, this is the second reported case of mycobacterium avium intracellulare thyroiditis. This case is also exemplary, given its occurrence in the absence of severe immunodepression, setting apart the mild impact on the immune system of affective disorder and of long duration's insulin-dependent diabetes.

Toxic hepatitis induced by antithyroid drugs: four cases including one with cross-reactivity between carbimazole and benzylthiouracil.

OBJECTIVE: This study was conducted to assess the occurrence of hepatic adverse effects encountered with antithyroid drugs. METHODS: Retrospective review of medical records of 236 patients with hyperthyroidism admitted in our department (in- or out-patients) from 1986 to 1992. RESULTS: Four patients (1.7%) were identified with toxic hepatitis which could reasonably be attributed to the use of antithyroid agent. Two patients had a cholestatic hepatitis induced by carbimazole (Néomercazole). Two others had a mixed (cholestatic and cytolytic) hepatitis following carbimazole. One of the latter two patients further experienced a cytolytic hepatitis which appeared after Benzylthiouracil (Basdène) had replaced carbimazole. Biological features of hepatitis disappeared in all cases after cessation of the incriminated drug, while biliary, viral and immunological searches were negative. Only 2 patients of our retrospective study experienced a mild or severe neutropenia. CONCLUSION: Toxic hepatitis is a potential adverse effect of antithyroid drugs which warrants, as for haematological disturbances, a pre-therapeutic determination and a careful follow-up of relevant biological markers. Moreover, hepatotoxicity may not be restricted to one class of antithyroid agents.

[Insulin receptors: structure and physiology]. / Récepteurs de l'insuline: structure et physiologie.

Insulin receptor is a transmembrane glycoprotein. It is synthetized, in endoplasmic reticulum, as a proreceptor which is processed (glycosylation, proteolytic cleavage) and transported to the cell surface. The receptor is a hetero-tetramer comprising 4 subunits: the two alpha-subunits are extracellular; they are held, through disulfide bonds, to the beta-subunits. These are located across the membrane; their intracellular domain possesses a tyrosine-kinase activity. Insulin receptor gene has been located on chromosome 19 and its nucleotide sequence is known. The first functional property of the receptor is to recognize the hormone. Specific and high affinity binding site is supported by the alpha subunit. Shortly after insulin binding, the tyrosine-kinase is activated, resulting in autophosphorylation and phosphorylation of various substrates. Current research focuses on these nature of there substrates which activate intracellular putative mediators of insulin action. Insulin-resistant states are associated with functional alteration of the receptor. But only a few cases are directly related to nucleotide mutations at the level of the gene resulting in structurally abnormal receptor.

Autoimmune insulin syndrome.

Initially described in Japan, the autoimmune insulin syndrome is caused by the presence of anti-insulin antibodies in patients who have never received insulin. This syndrome accounts for spontaneous or reactive hypoglycaemia with very high levels of total immuno-reactive insulin. Discordance between the levels of immunoreactive insulin and C peptide indicate the possible presence of anti-insulin antibodies; this can avoid an incorrect diagnosis of insulinoma. These autoimmune hypoglycaemias often present a difficult diagnostic problem in distinguishing them from factitious hypoglycaemia. The course of the autoimmune insulin syndrome is usually favourable, with a spontaneous rapid diminution of the levels of anti-insulin antibodies. The reasons for the appearance of anti-insulin antibodies and the exact mechanisms of the hypoglycaemia remain uncertain. However, the frequent association of the autoimmune insulin syndrome with certain autoimmune diseases suggest a common immune dysfunction. Drugs containing a sulphydryl group have been implicated in the aetiology of this syndrome.

[Autoimmune hypoglycemia: the fault of pyritinol?]. / Hypoglycémie autoimmune: responsabilité du pyritinol?

Initially reported in Japan, autoimmune hypoglycemia is related to the presence of insulin-binding antibodies, even in patients who have never been treated with insulin. The authors report a case of spontaneous autoimmune hypoglycemia in a French woman receiving pyritinol. The difference between insulin and C peptide radioimmunoassay levels prompted a search for insulin antibodies. In vitro studies confirmed their presence and showed that they were immunoglobulins G with two binding sites without species specificity. The outcome of autoimmune hypoglycemia is usually favourable, with a rapid decrease of insulin antibodies but steroid therapy is needed when serious clinical manifestations are present. The differential diagnosis with factitious hypoglycemia may be difficult. The reasons for the appearance of the insulin antibodies and the exact mechanisms of hypoglycemia remain hypothetical. However, drugs with a sulfhydril group, such as pyritinol, could play a causative role in this syndrome.

[Acanthosis nigricans, hyperandrogenism, insulin resistance and mixed hyperlipemia]. / Acanthosis nigricans, hyperandrogénie, insulinorésistance et hyperlipémie mixte.

We report the case of a 22-year old woman who presented skin lesions of acanthosis nigricans, hirsutism and secondary amenorrhoea. She had high plasma levels of adrenal androgens and low plasma levels of sex steroid binding protein. Polycystic ovaries were discovered in the course of a laparotomy performed for paraovarian cyst. An oral glucose tolerance test revealed a state of hyperinsulinism with intolerance to carbohydrates, while the body mass index was normal. This insulin resistant state corresponded in vitro to a decrease in the number of erythrocyte insulin receptors without decrease in their affinity for insulin. Following paradoxical improvement during a full-term pregnancy, there was gradual deterioration of diabetes control requiring insulin therapy. This metabolic decompensation was accompanied by major hyperlipaemia followed by acute haemorrhagic pancreatitis. This case illustrates the course of a type A insulin resistance syndrome which was detected at an early stage in front of an hirsutism-acanthosis nigricans association. The underlying pathogenic mechanisms of these pathologies are discussed.