Redox activity of nickel and vanadium porphyrins: a possible mechanism behind petroleum genesis and maturation?

The presence of metalloporphyrins in crude oil has been known for many years. In contrast, their role on the physical-chemical properties is only now beginning to be understood. In this study, we test using high-level ab initio calculations, the hypothesis of a possible redox catalytic activity of vanadium and nickel metalloporphyrins in crude oil, illustrated by the oxidation of methanol to formaldehyde and hydrogen dissociation, respectively. This process which may take place during petroleum genesis and maturation, explains some of its physical-chemical properties, such as polar chains, the absence of alcohols, the trapping of porphyrins within macromolecular aggregates.

High prevalence of diabetes mellitus and hospital-related hyperglycaemia in French general wards.

AIM: The study evaluated the in-hospital prevalence of diabetes and hospital-related hyperglycaemia in a variety of French general wards. METHODS: The multicentre cross-sectional study involving nine French hospitals measured venous fasting plasma glucose (FPG) on a single day in patients hospitalized in adult medical and surgical short-term wards. Diabetes status and length of stay were recorded. RESULTS: Of the 2141 inpatients included in the study, 355 (16.5%) had known diabetes, 156 (7.3%) had screened diabetes (FPG ≥7 mmol/L with no diabetes history), 515 (24.1%) had impaired fasting glucose (IFG; FPG 5.5-6.9 mmol/L) and 1115 (52.1%) had normal glucose values (FPG < 5.5 mmol/L). Diabetes prevalence varied from 11% in hospitals in the west of France to 21% in hospitals in northern and eastern regions. The highest known diabetes prevalence was observed in units for cardiovascular surgery (33%), infectious diseases (27%) and kidney disorders (26%). In cancer units, one-fifth of patients had screened diabetes and one-sixth had known diabetes. Among the known diabetes patients, 127 (36%) were already being treated with insulin, while an additional 41 (12%) started insulin therapy during their hospital stay. Patients with known and screened diabetes were older (70.8 ± 12.2 and 71.1 ± 15.6 years, respectively) than the normal-glucose patients (65.6 ± 18.9 years; P<0.001). Average length of stay was no different between known diabetes and normal-glucose patients after adjusting for age (11.3 ± 7.7 vs 10.0 ± 7.4 days; NS). CONCLUSION: Overall, metabolic glucose disorders (known or screened diabetes and IFG) were found in 48% of inpatients in various French hospital general wards.

Clinical outcomes of lung-transplant recipients treated by voriconazole and caspofungin combination in aspergillosis.

BACKGROUND AND OBJECTIVE: Invasive pulmonary aspergillosis (IPA) is a serious cause of death among immune-compromised patients such as organ-transplant recipients. Recently, voriconazole has been approved for first-line therapy in IPA. Theoretically, optimal voriconazole blood level (superior to 1 mg/L according to recent studies) should be reached within 24 h. In practice, a significantly longer time seems to be needed in lung-transplant recipients. Therefore, caspofungin is now used in combination with voriconazole to provide cover against Aspergillus spp. infection during this gap. The first aim of this study was to investigate Aspergillus spp. infection treated with this combination and the atter's tolerability. The median time for attainment of apparently active blood levels in lung transplant recipients were compared between those with cystic fibrosis and those without. METHODS: Lung-transplant recipients who received a combination of voriconazole and caspofungin between 2002 and 2008 as primary therapy were identified retrospectively. The median number of days to reach active voriconazole blood levels was compared between cystic fibrosis and other patients by Student's t-test. Statistical significance was defined by P-value <0.05. RESULTS: Four patients were treated for Aspergillus colonization before transplantation and their culture were negative at 90 days. Eleven patients were treated for proven or probable invasive aspergillosis and 14 of them had a complete response. Hallucinations (n = 2) and significant hepatic toxicity (n = 2) were reported. Among the 15 studied transplant recipients, a median of 12.3 days was observed for active voriconazole blood levels to be reached. With cystic fibrosis patients, time tended to be longer than with other recipients (14.9 days vs. 8.3 days). Tacrolimus blood levels (between 5 and 15 ng/mL) may have been increased by voriconazole. CONCLUSION: This retrospective study describes practical experience in the management of this rare and severe disease in a referral centre for cystic fibrosis lung transplantation. Voriconazole and caspofungin combination was acceptably safe and was associated with good clinical outcomes in almost all patients. We showed that in 15 lung-transplant recipients a median of 12.3 days was required for voriconazole to reach high enough blood levels. Caspofungin in combination with voriconazole provides cover against Aspergillus infection during the period when voriconazole may be at subtherapeutic levels with good tolerability.

[Clinical and economical evaluation of bivalirudin during percutaneous coronary interventions]. / Evaluations clinique et économique de la bivalirudine au cours des procédures d'angioplasties coronaires.

Bivalirudin, with provisional GP IIb/IIIa inhibitor use allows the same protection against ischemic complications while reducing the hemorrhagic complications compared with the systematic association of a GP IIb/IIIa inhibitor plus heparin (The Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events-2 [Replace-2]). In clinical practice, the use of heparin is not systematically associated with a GP IIb/IIIa inhibitor. That's why we studied the clinical and economic interest of bivalirudin only versus heparin (UFH) only. Opened pragmatic monocentric study carried out in 2007. We made a chronological matching: for each patient treated with bivalirudin, we included the next patient with the same clinical presentation treated with unfractionated heparin. Ninety-two patients were included (46 in each group). The need for a GP IIb/IIIa inhibitor during the PCI was not significantly different between the two groups (p=0.11). No major hemorrhagic complications were observed in the two groups. Prevalence of ecchymosis was not significantly different: 22 % in the UFH group versus 13 % in the bivalirudin group (p=0.27). The average troponin level the next day was significantly higher in the bivalirudin group (p=0,049), although the change in troponin levels before and after the procedure was similar in the two groups. The average cost by patient of anticoagulation by bivalirudin and HNF is very different, respectively 473+/-150 and 51+/-146 euro (p=0.0001). Bivalirudin can be an interesting alternative for patients with a high risk of having complications. But considering its cost this therapy must be used only for selected patients.

The GnRH receptor gene is preferentially expressed in functioning gonadotroph adenomas and displays a Mae III polymorphism site.

OBJECTIVE: Given the central role of the GnRH receptor (GnRHR) in the regulation of the gonadotrophin secretion, it might be implicated directly or indirectly in the pathogenesis of gonadotroph tumours. DESIGN: We determined if GnRHR mRNA was expressed in gonadotroph tumours using RT-PCR and analysed the GnRHR gene for the presence of mutations in its coding region, using direct sequencing of PCR products. Results were analysed according to the pattern of expression of alpha, beta-FSH and beta-LH subunit (SU) genes. SUBJECTS: RNA was extracted from 20 gonadotroph tumours identified by immunohistochemistry (> 10% of stained cells): 9 adenomas were functioning (high serum gonadotrophin levels), 3 were associated with high alpha-SU levels and 8 were nonfunctioning. Genomic DNA was extracted from 64 normal subjects. RESULTS: We found GnRHR mRNA in 12 tumours (60%): 8/9 functioning (88%), 1/3 alpha-secreting (33%) and 3/8 nonfunctioning (37.5%) gonadotroph adenomas. There was a significant association between GnRHR expression and immunostaining for beta-FSH (P = 0.014). The nucleotide sequence of the amplified products was identical to that of human pituitary except for the presence, in 3 functioning adenomas, of a silent C to T transition at nucleotide 453 encoding for the serine residue situated in the second intracellular loop at position 151. Heterozygosity provided evidence that both alleles were transcribed in these tumours. This substitution creates a Mae III restriction site. Genomic DNA from normal subjects were then tested for the presence of this new polymorphism. The frequency of the heterozygosity (18.7%) was not significantly different from that found in gonadotroph tumours (25%) and this new Mae III polymorphism site cannot be used as a tumoural marker. CONCLUSION: The GnRHR gene is preferentially expressed in functioning rather than in nonfunctioning gonadotroph adenomas, but no mutations altering the coding region of the gene were found to further substantiate its role in the pathogenesis of gonadotroph tumours.

Glycoprotein hormone alpha-subunit secretion in prolactinomas and in non-functioning adenomas: relation with the tumour size.

OBJECTIVE: Free glycoprotein hormone alpha-subunit plasma levels have been reported to be increased in glycoprotein hormone-secreting adenomas and in acromegaly, but rarely in prolactinomas and in only two cases of Cushing's disease. The prevalence of elevated plasma alpha-subunit levels in patients with non-functioning adenomas is still unclear. In addition, no previous work has described plasma alpha-subunit levels in a comprehensive series of adenomas characterized by in-vivo secretion and/or immunocytochemistry. PATIENTS: Thirty-seven patients with definite prolactinomas and 48 with non-functioning tumours characterized by immunocytochemistry were studied, from a series of 145 consecutive patients including 33 acromegalics, 18 patients with glycoprotein hormone-secreting adenomas and 9 with Cushing's disease. MEASUREMENTS: Plasma free alpha-subunit was measured by radioimmunoassay in all patients and in a large sample of normal subjects to establish normal ranges according to sex, age and menstrual status. Tumour volume index was the product in cm3 of length, width and height of the adenoma as assessed by computerized tomography or magnetic resonance imaging. RESULTS: Twelve of the 37 (32%) patients with prolactinomas had increased plasma alpha-subunit levels; their tumours were significantly larger with significantly higher plasma PRL levels than those of patients without increased plasma alpha-subunit levels (P < 0.02). All prolactinomas above 50 cm3 were associated with alpha-subunit secretion, whereas only 6 of 29 smaller tumours were similarly associated. Twelve of the 48 'non-functioning' adenomas actually secreted alpha-subunit in vivo: 8 gonadotrophin-secreting, 2 'pure' alpha-secreting, one with negative immunocytochemistry and one necrotic adenoma. Their volumes were significantly higher than those of adenomas without increased plasma alpha-subunit levels (P < 0.04). Plasma alpha-subunit levels were increased in the 6 patients with TSH-secreting adenomas, 8 of 12 with FSH-secreting adenomas, 11 of 33 acromegalics and none of those with Cushing's disease. CONCLUSION: Plasma free alpha-subunit levels were increased in 49 of 145 patients (34%). For prolactinomas and 'non-functioning' adenomas, alpha-subunit hypersecretion was seen more often with larger tumours. Half of the cases with increased free alpha-subunit in this series were patients harbouring an adenoma which did not stain for an intact glycoprotein hormone.

Inhibin and follicle-stimulating hormone levels in gonadotroph adenomas: evidence of a positive correlation with tumour volume in men.

OBJECTIVE: Gonadotroph adenomas are generally revealed by symptoms of mass effect at the stage of macroadenoma. Most of them hypersecrete FSH and/or gonadotrophin subunits. Rarely they hypersecrete LH, which could induce endocrinological symptoms. As the glycoprotein inhibin is secreted by the gonads under FSH control, we have evaluated whether high immunoreactive inhibin (iINH) levels correlated with FSH hypersecretion and whether iINH and FSH levels were related to tumour volume in subjects with gonadotroph adenomas. PATIENTS: Forty-five patients (30 men, 15 women) were retrospectively selected on the basis of immunostaining technique using specific antibodies raised against FSH-beta, LH-beta and glycoprotein alpha-subunit. MEASUREMENTS: Immunoreactive inhibin (iINH) was measured by radioimmunoassay using antiserum 1989 raised to bovine inhibin. Tumour volume index was the product in cm3 of length, width and height of the adenoma as assessed by computerized tomography. RESULTS: In men (age 21-61 years), iINH levels were positively correlated with FSH levels (Spearman's r = 0.67, P < 0.001), and both iINH and FSH levels were significantly correlated with tumour volume index (Spearman's r = 0.38, P < 0.05 and r = 0.39, P < 0.05 respectively). In the subgroup of men with normal FSH levels (n = 17), the correlation of FSH with tumour volume index was high: Spearman's r = 0.56, P < 0.05. In the post-menopausal women (n = 8, age > 55 years), iINH levels were undetectable or below the follicular phase range regardless of FSH values. In the premenopausal women (n = 7, age 22-49 years, follicular phase or amenorrhoea) iINH levels were above follicular phase range in three women including one who had very high FSH levels. CONCLUSIONS: These data show that in men with gonadotroph adenoma FSH levels are related to tumour mass and suggest that a significant part of circulating FSH in patients with normal FSH levels arises from the tumour. The significant correlation between iINH and FSH levels demonstrates that tumoral FSH is bioactive and that high iINH levels do not exert any feedback control on tumoral FSH secretion. Therefore the coexistence of high FSH levels with high iINH levels is strongly suggestive of a gonadotroph adenoma. Gonadotroph adenomas seem to represent a unique model of long-term FSH stimulation of inhibin-producing cells, in some way analogous to that created by repetitive administration of exogenous FSH.

Evaluation of 29 monoclonal and polyclonal antibodies used in the diagnosis of pituitary adenomas. A collaborative study from pathologists of the Club Français de l'Hypophyse.

Fifteen polyclonal antibodies (pAbs) and 14 monoclonal antibodies (mAbs) directed against hGH, hPRL, beta hFSH, beta hLH, beta hTSH and alpha-subunit were assessed by five different laboratories on normal and adenomatous pituitary tissues. This study aims at providing pathologists with a selected panel of antisera suitable for diagnosis, and appreciating the interest of the recently introduced mAbs. All the anti-hGH Abs proved to be specific (3 pAbs and 4 mAbs); three mAb out of four gave a few false-negative reactions. Three out of six polyclonal anti-hPRL showed cross-reactivity with hGH; anti-hPRL mAbs gave a strong staining with no false-negativity detected so far. MAbs proved to be more efficient for detecting glycoprotein hormones and alpha subunit than pAbs, which, in several cases, gave widespread cross-reactivity. This lack of specificity could explain the noticeable discrepancies reported so far in the appraisal of gonadotropic and somatoprolactinic adenomas.