Homozygous whole body Cbs knockout in adult mice features minimal pathology during ageing despite severe homocysteinemia.

Deficiencies in Cystathionine-ß-synthase (CBS) lead to hyperhomocysteinemia (HHCy), which is considered a risk factor for cardiovascular, bone and neurological disease. Moreover, CBS is important for the production of cysteine, hydrogen sulfide (H2 S) and glutathione. Studying the biological role of CBS in adult mice has been severely hampered by embryological disturbances and perinatal mortality. To overcome these issues and assess the effects of whole-body CBS deficiency in adult mice, we engineered and characterized a Cre-inducible Cbs knockout model during ageing. No perinatal mortality occurred before Cbs-/- induction at 10 weeks of age. Mice were followed until 90 weeks of age and ablation of Cbs was confirmed in liver and kidney but not in brain. Severe HHCy was observed in Cbs-/- (289 ± 58 µM) but not in Cbs+/- or control mice (<10 µM). Cbs-/- showed impaired growth, facial alopecia, endothelial dysfunction in absence of increased mortality, and signs of liver or kidney damage. CBS expression in skin localized to sebaceous glands and epidermis, suggesting local effects of Cbs-/- on alopecia. Cbs-/- showed increased markers of oxidative stress and senescence but expression of other H2 S producing enzymes (CSE and 3-MST) was not affected. CBS deficiency severely impaired H2 S production capacity in liver, but not in brain or kidney. In summary, Cbs-/- mice presented a mild phenotype without mortality despite severe HHCy. The findings demonstrate that HHCy is not directly linked to development of end organ damage.

Clinical follow-up on weight loss, glycemic control, and safety aspects of 24 months of duodenal-jejunal bypass liner implantation.

BACKGROUND: The duodenal-jejunal bypass liner (DJBL) is an endoscopic device designed to induce weight loss and improve glycemic control. The liner is licensed for a maximum implant duration of 12 months. It might be hypothesized that extension of the dwelling time results in added value. The goals of our study were to determine weight change, change in glycemic control, and safety in patients with an intended 24 months of DJBL dwelling time. METHODS: Patients were initially selected for a 12-month implantation period. When no physical complaints or adverse events (AEs) occurred, motivated patients who responded well were selected for extension of dwelling time to 24 months. Patients underwent a control endoscopy 12 months after implantation and visited the out-patient clinic every 3 months up to explantation. Patients agreed to remove the DJBL when complaints or AEs occurred that could not be treated conservatively. RESULTS: Implantation was extended in 44 patients, and 24 (55%) patients completed the full 24 months. Twenty patients required early removal due to AEs. During dwelling time, body weight decreased significantly (15.9 kg; TBWL 14.6%). HbA1c decreased non-significantly (4.9 mmol/mol). The number of insulin users and daily dose of insulin both decreased significantly. At 24 months after removal, glycemic control had worsened, while body weight was still significantly lower compared to baseline. In total, 68% of the patients experienced at least one AE. Two patients developed a hepatic abscess. CONCLUSIONS: DJBL treatment results in significant weight loss and improves glycemic control during implantation. The largest beneficial effects occur during the first 9-12 months after implantation. Extension of dwelling time to 24 months results only in stabilization of body weight and glycemic control. After explantation, weight improvements are maintained, but glycemic control worsens. As the cumulative risk of AEs increases with time, a maximal dwelling time of 12 months is advisable.

Genetic Obesity and Bariatric Surgery Outcome in 1014 Patients with Morbid Obesity.

BACKGROUND: Mutations in the leptin-melanocortin pathway genes are known to cause monogenic obesity. The prevalence of these gene mutations and their effect on weight loss response after bariatric surgery are still largely unknown. OBJECTIVE: To determine the prevalence of genetic obesity in a large bariatric cohort and evaluate their response to bariatric surgery. METHODS: Mutation analysis of 52 obesity-associated genes. Patient inclusion criteria were a BMI > 50 kg/m2, an indication for revisional surgery or an early onset of obesity (< 10 years of age). RESULTS: A total of 1014 patients were included, of whom 30 (3%) were diagnosed with genetic obesity, caused by pathogenic heterozygous mutations in either MC4R, POMC, PCSK1, SIM1, or PTEN. The percentage total body weight loss (%TBWL) after Roux-en-Y gastric bypass (RYGB) surgery was not significantly different for patients with a mutation in MC4R, POMC, and PCSK1 compared with patients lacking a molecular diagnosis. Of the confirmed genetic obesity cases, only patients with MC4R mutations receiving a sleeve gastrectomy (SG) showed significantly lower %TBWL compared with patients lacking a molecular diagnosis, during 2 years of follow-up. CONCLUSIONS: In this cohort of morbid obese bariatric patients, an estimated prevalence of monogenic obesity of 3% is reported. Among these patients, the clinical effects of heterozygous mutations in POMC and PCSK1 do not interfere with the effectiveness of most commonly performed bariatric procedures within the first 2 years of follow-up. Patients with MC4R mutations achieved superior weight loss after primary RYGB compared with SG.

Weight Loss, Remission of Comorbidities, and Quality of Life After Bariatric Surgery in Young Adult Patients.

INTRODUCTION: One of the current criteria for bariatric surgery is to be of an age between 18 and 65 years. In all the available literature, there is a lack of studies focusing on the results of bariatric surgery in younger patient. This could be of great interest because the weight loss response can be altered by differences in metabolism or compliance rate. In recent years, a high amount of patients between 18 and 25 years of age have undergone bariatric surgery in our center, and it is our aim to evaluate the weight loss results in this youngest patient group. METHODS: All preoperative and perioperative data from patients aged 18-25 and 35-55 years (control group) were collected retrospectively. Bariatric procedures took place between 2011 and 2014. Follow-up data were gathered prospectively by collecting (laboratory) measurements and questionnaires. RESULTS: In total, 103 young adults (mean age 22.5) were matched to 103 adult control patients (mean age 42.6) on BMI and date of surgery. Of the young adults' group, 75 patients underwent a Roux-en-Y gastric bypass (RYGB) compared with 80 patients in the control group. Three years after RYGB, mean %total body weight loss (%TBWL) was 34 (± 9) and 30.3 (± 9) (p = 0.03), respectively. CONCLUSION: Bariatric surgery is effective in young adults, and results after RYGB are even better compared with age groups in which bariatric surgery is most often performed. The high remission rate of comorbidities shows the importance of effective treatment options at a young age and preventing damaging effects in the long term.

The Effect of Obesity on Anti-Xa Concentrations in Bariatric Patients.

BACKGROUND: Morbidly obese patients are at increased risk to develop venous thromboembolism (VTE), especially after bariatric surgery. Adequate postoperative thrombosis prophylaxis is of utmost importance. It is assumed that morbidly obese patients need higher doses of low molecular weight heparin (LMWH) compared to normal-weight patients; however, current guidelines based on relative efficacy in obese populations are lacking. OBJECTIVES: First, we will evaluate the relationship between body weight descriptors and anti-Xa activity prospectively. Second, we will determine the dose-linearity of LMWH in morbidly obese patients. SETTING: This study was performed in a general hospital specialized in bariatric surgery. METHODS: Patients were scheduled for a Roux-en-Y gastric bypass with a total bodyweight (TBW) of ≥ 140 kg. Patients (n = 50, 64% female) received a daily postoperative dose of 5700 IU of nadroparin for 4 weeks. Anti-Xa activity was determined 4 h after the last nadroparin administration. To determine the dose linearity, anti-Xa was determined following a preoperative dose of 2850 IU nadroparin in another 50 patients (52%). RESULTS: TBW of the complete group was 148.5 ± 12.6 kg. Mean anti-Xa activity following 5700 IU nadroparin was 0.19 ± 0.07 IU/mL. Of all patients, 32% had anti-Xa levels below the prophylactic range. Anti-Xa activity inversely correlated with TBW (correlation coefficient - 0.410) and lean body weight (LBW; correlation coefficient - 0.447); 67% of patients with a LBW ≥ 80 kg had insufficient anti-Xa activity concentrations. No VTE events occurred. CONCLUSIONS: In morbidly obese patients, a postoperative dose of 5700 IU of nadroparin resulted in subprophylactic exposure in a significant proportion of patients. Especially in patients with LBW ≥ 80 kg, a higher dose may potentially be required to reach adequate prophylactic anti-Xa levels.

Revision of failed laparoscopic adjustable gastric banding to Roux-en-Y gastric bypass.

BACKGROUND: The most common bariatric surgical operation in Europe, laparoscopic adjustable gastric banding (LAGB), is reported to have a high incidence of long-term complications. Also, insufficient weight loss is reported. We investigated whether revision to Roux-en-Y gastric bypass (RYGBP) is a safe and effective therapy for failed LAGB and for further weight loss. METHODS: From Jan 1999 to May 2004, 613 patients underwent LAGB. Of these, 47 underwent later revisional Roux-en-Y gastric bypass (RYGBP). Using a prospectively collected database, we analyzed these revisions. All procedures were done by two surgeons with extensive experience in bariatric surgery. RESULTS: All patients were treated with laparoscopic (n=26) or open (n=21) RYGBP after failed LAGB. Total follow-up after LAGB was 5.5+/-2.0 years. For the RYGBP, mean operating time was 161+/-53 minutes, estimated blood loss was 219+/-329 ml, and hospital stay was 6.7+/-4.5 days. There has been no mortality. Early complications occurred in 17%. There was only one late complication (2%)--a ventral hernia. The mean BMI prior to any form of bariatric surgery was 49.2+/-9.3 kg/m2, and decreased to 45.8+/-8.9 kg/m2 after LAGB and was again reduced to 37.7+/-8.7 kg/m2 after RYGBP within our follow-up period. CONCLUSION: Conversion of LAGB to RYGBP is effective to treat complications of LAGB and to further reduce the weight to healthier levels in morbidly obese patients.

Formation and repair of cisplatin-induced adducts to DNA in cultured normal and repair-deficient human fibroblasts.

The formation and repair of cisplatin [cis-PtCl2(NH3)2] adducts in the DNA of cultured normal and repair-deficient human fibroblasts are presented in relation to cell survival after cisplatin treatment. Directly after treatment with cisplatin, in normal (MB), Fanconi's anemia (FA), and xeroderma pigmentosum (XP) fibroblasts four platinated products are found. The major adduct is cisplatin bound to two neighboring guanines, Pt-GG (62-75%). A less abundant product is cisplatin bound to an AG sequence (Pt-AG). Binding to two guanines separated by one or more bases or to two guanines in opposite DNA strands (together measured as G-Pt-G) and cisplatin bound monofunctionally to guanine (Pt-G) are also found in small amounts. The distribution of the four products is similar to that found previously, in in vitro systems as well as in living cells. Directly after cisplatin treatment, the removal of cisplatin-DNA adducts is fast in normal and FA fibroblasts, whereas in XP fibroblasts adduct removal proceeds slowly throughout the repair period studied. Both FA and XP fibroblasts are extremely sensitive to cisplatin with regard to cell killing. For FA fibroblasts this sensitivity may be attributed to the fact that in these cells initially more DNA-adducts are formed than in normal fibroblasts, and/or to their known deficiency in the repair of DNA interstrand cross-links. For XP fibroblasts this sensitivity may be caused by their deficiency in the fast repair process, known as excision repair.

Formation and repair of DNA interstrand cross-links in relation to cytotoxicity and unscheduled DNA synthesis induced in control and mutant human cells treated with cis-diamminedichloroplatinum(II).

A comparative study was performed with a variety of human cell lines on the effects of treatments with cis-diamminedichloroplatinum(II) (cisplatin) on cell survival and the induction of unscheduled DNA synthesis. In addition to control fibroblasts (Han, MB), cell lines defective in DNA repair were used [xeroderma pigmentosum, XP(A) and XP(F), and Fanconi's anemia (FA)], as well as cells deficient in arylsulfatase A (mucolipidosis II, ML1 and ML2). Ultraviolet light and mitomycin C were included in this study as model DNA-damaging agents. Furthermore, induction of DNA interstrand cross-links by cisplatin and their repair were studied. As for survival, only XP cells were abnormally sensitive to ultraviolet light, and only FA cells were abnormally sensitive to mitomycin C. To cisplatin, however, all mutants tested were more sensitive (2 to 5 times) than were normal cells. Unscheduled DNA synthesis induction by ultraviolet light was strong in all but the XP cells; the other two agents did not induce unscheduled DNA synthesis. Induction of DNA interstrand cross-links by cisplatin was linear with dose. Formation continued for up to 18 to 24 h after treatment. During this period, all cells but the ML mutants responded similarly. In ML cells, much fewer cross-links were induced, which were repaired rapidly. In FA cells, accumulation continued for at least 96 h; in the other cells, most of the cross-links had been removed after that period. In the discussion, the cisplatin-induced DNA interstrand cross-links are proposed as an important potentially lethal lesion, in view of their persistence in the highly sensitive FA cells. Furthermore, the possible involvement of certain steps of the long-patch excision repair pathway in the removal of this lesion is considered. The sensitivity of ML cells to cisplatin is attributed to cytoplasmic effects, rather than to chromosomal damage.

cis-Diamminedichloroplatinum(II)-induced DNA adducts in peripheral leukocytes from seven cancer patients: quantitative immunochemical detection of the adduct induction and removal after a single dose of cis-diamminedichloroplatinum(II).

The same four platinum-containing products identified in nucleolytic digests of DNA treated with cisplatin (cisDDP) in vitro now have been shown to be present in digested DNA originating from human cells after in vivo exposure. The immunochemical detection of these products at the fmol level became possible by the application of an existing and two newly raised rabbit antisera with specificities towards the various cisDDP-DNA derived products. In DNA isolated from white blood cells of a number of cancer patients treated with the drug for the first time, intrastrand cross-links on pGpG base sequences appeared to be the main adduct, followed by the intrastrand cross-links on pApG sequences, interstrand cross-links, and/or intrastrand cross-links on two guanines separated by one or more bases and a very low amount of monofunctionally bound cisDDP to guanine; typical proportions were 65, 22, 13, and less than 1%, respectively. The induction and removal of the main adduct, the intrastrand cross-link on pGpG sequences, have been studied in DNA from blood samples of six male patients after their first cisDDP treatment. The results indicate that the susceptibility of blood cells to cisDDP-DNA adduct formation can show strong individually determined differences. From the data it is also clear that a substantial part of the adducts is removed within the first 24 h after the cisDDP-infusion.

Kinetics of the formation and removal of cisplatin-DNA adducts in blood cells and tumor tissue of cancer patients receiving chemotherapy: comparison with in vitro adduct formation.

During chemotherapy with a cisplatin-containing combination of drugs, 217 blood samples from 30 cancer patients were analyzed for the presence of the main cisplatin-DNA adduct cis-Pt(NH3)2d(pGpG) (Pt-GG). Cisplatin was administered during 3-h infusions on each of 5 consecutive days, resulting in increasing adduct levels which, on the average, were about twice as high after the fifth as after the first infusion. Higher levels were found in blood samples of patients who received the same total amount of cisplatin in one single 3-h infusion. No significant differences in adduct levels were found during first and repeated courses. The nonlinear dependence of adduct levels on total dose can be attributed to removal of adducts. At 21 h after a very first cisplatin infusion 76% of the adducts were removed. Lower percentages of removal were observed over the 21-h periods following the fourth and fifth infusions of 5-day courses (49 and 53%, respectively). After the initial 21 h the removal of adducts continued, albeit at a slower rate. Substantial interindividual variation was found in the adduct levels, which did correlate with the levels obtained after in vitro cisplatin treatment of blood samples from the same patients but not with their age or gender. Testicular cancer patients with complete tumor response showed higher adduct levels in their blood than those with partial response or progressive disease. When blood samples from 8 healthy volunteers were treated with cisplatin in vitro, the person-to-person variation in adduct levels and the intraindividual variation observed over a 2-year period were found to be in the same range, which was narrower than that observed with samples from treated patients. In vitro studies with human blood showed that the formation of the Pt-GG adduct is proportional to cisplatin concentration and complete after about 1 hour. In some of the in vivo and in vitro cisplatin-treated blood samples, all 4 known platinum-DNA adducts were determined. In all cases Pt-GG was by far the major adduct, and no significant differences were observed with respect to the relative amounts of the 4 adducts. Similar adduct ratios were found in DNA from a testicular tumor obtained from a patient who underwent orchidectomy; the Pt-GG adduct level was about 10-fold higher than that in his blood cells.

Hydrodynamic characterization of the size and shape of atropinesterase from Pseudomonas putida.

Atropinesterase from Pseudomonas putida has been investigated by means of different ultracentrifugation methods under native and denaturing conditions. The following quantities were determined: sedimentation coefficient, translational diffusion and friction coefficient, partial specific volume and molecular weight. From these data the size, shape and hydration of the enzyme molecule in solution were estimated. The results suggest that atropinesterase is a globular protein which consists of a single polypeptide chain with a molecular weight of about 30,000. In solution under non-denaturing conditions, it occurs mainly as a dimer which hydrodynamically behaves as a rigid impenetrable particle. Calculations based on the spheroid model indicate that this particle resembles a hydrated sphere with a diameter of 6.1 +/- 0.2 nm and a hydration of 0.4 +/- 0.1 g of H2O/g of protein rather than a significantly less hydrated ellipsoid of revolution. Under denaturing conditions dissociation into monomers takes place. The effects of sodium dodecyl sulphate (SDS) on size and shape suggest that dimerization results from side-by-side association of two elongated monomers rather than from end-to-end association. Approximately 57 molecules of SDS are bound per dimer before dissociation occurs concomitant with the additional binding of about 19 molecules of detergent.

Is reimplantation of the duodenal-jejunal bypass liner feasible?

BACKGROUND: The endoscopic ally implanted DJBL is a 60-cm impermeable fluoropolymer device, which prevents food from making contact with the proximal intestine. It was designed to induce weight loss and treat type 2 diabetes mellitus (T2DM). OBJECTIVES: To evaluate the feasibility, safety, and effectiveness of duodenal-jejunal bypass liner (DJBL) reimplantation. SETTING: Prospective, observational study was conducted at the department of surgery and gastroenterology of the Rijnstate hospital, Arnhem, the Netherlands, between 2009 and 2011. METHODS: Five obese patients with T2DM with body mass index (BMI) = Mass (kg) / height (m(2)), ranging from 30-35 kg/m(2) who completed the follow-up after their first implant and underwent removal of the DJBL after 6 months, were selected for reimplantation after an additional 18 months of follow-up. Weight loss, BMI, and HbA1 c were analyzed before and twelve months after reimplantation. RESULTS: In all 5 patients, the DJBL was implanted and explanted without any complications. Also the reimplantation and reexplantation occurred without any complications. Median weight decreased significantly from 105 kg to 95 kg, and BMI decreased from 33 to 29. The glycated hemoglobin (HbA1 c) level decreased from 8.4% to 7.3% by the first implantation but it wasn't significant. CONCLUSIONS: Reimplantation of DJBL is feasible, deemed safe, and showed additional weight loss.

Age-dependent accumulation of alkali-labile sites in DNA of post-mitotic but not in that of mitotic rat liver cells.

The amount of spontaneous damage in the DNA of rat liver cells was measured by using the alkaline elution assay. An age-related increase of approximately 700 detectable alkali-labile sites (80%) was found for rat parenchymal liver cells; cells from 6-month-old rats contained approximately 900 alkali-labile sites per cell while cells from 36-month-old rats contained approximately 1600 alkali-labile sites. In contrast to the situation with the postmitotic parenchymal liver cells, no age-related increase in the number of alkali-labile sites was found for the non-parenchymal liver cell fraction, which has a higher mitotic activity. These results support the hypothesis that aging takes place predominantly in postmitotic cells.

Monitoring anticoagulant therapy by activated partial thromboplastin time: hirudin assessment. An evaluation of native blood and plasma assays.

BACKGROUND: Recombinant hirudin (RH) is a new anticoagulant for prophylaxis and treatment of venous and arterial thrombosis. To which extent the activated partial thromboplastin time (APTT) is suitable for monitoring of RH has not been properly evaluated. Recently, a capillary whole blood device was developed for bed-side monitoring of the APTT and it was demonstrated that this device was suitable to monitor heparin therapy. However, monitoring of RH was not evaluated. STUDY OBJECTIVES: To evaluate in vitro and ex vivo the responsiveness and reproducibility for hirudin monitoring of the whole blood monitor and of plasma APTT assays, which were performed with several reagents and two conventional coagulometers. RESULTS: Large interindividual differences in hirudin responsiveness were noted in both the in vitro and the ex vivo experiments. The relationship between the APTT, expressed as clotting time or ratio of initial and prolonged APTT, and the hirudin concentration was nonlinear. A 1.5-fold increase of the clotting times was obtained at 150-200 ng/ml plasma. However, only a 2-fold increase was obtained at hirudin levels varying from 300 ng to more than 750 ng RH/ml plasma regardless of the assays. The relationship linearized upon logarithmic conversion of the ratio and the hirudin concentration. Disregarding the interindividual differences, and presuming full linearity of the relationship, all combinations were equally responsive to hirudin. CONCLUSIONS: All assays were equally responsive to hirudin. Levels up to 300 ng/ml plasma can be reliably estimated with each assay. The manual device may be preferable in situations where rapid availability of test results is necessary.

Impaired haemostasis by intravenous administration of a gelatin-based plasma expander in human subjects.

The aim of this study was to investigate the effects of a gelatin-based plasma expander on blood coagulation and haemostasis in human subjects. Six healthy men were studied in a randomised, controlled cross-over study to investigate the effects of a 60 min intravenous infusion of either 1 l gelatin-based plasma substitute (Gelofusine) or 0.9% NaCl (control). The infusion of gelatin resulted in a 1.7 fold increase in bleeding time at 60 min and a 1.4 fold increase at 120 min, while saline had no effect (p <0.05). Aggregation studies revealed a significant impairment of ristocetin-induced platelet aggregation (p <0.05), associated with a substantial decrease of vWF:ag (-32% vs. -5%, p <0.05) and ristocetin co-factor (-29% vs. +1%, p <0.05) and without in vitro impairment of the platelet glycoprotein 1b receptor. Gelatin caused a decrease in thrombin-antithrombin complexes (-45% vs. -4%, p <0.05) and F1+2 (-40% vs. +1%, p <0.05). The decrease in circulating levels of vWF:ag, vWF R:Co, thrombin-antithrombin complexes and F1+2 was more than could be expected by the calculated plasma-dilution generated by Gelofusine. Our results demonstrated that the administration of a gelatin-based plasma substitute results in a significant impairment of primary haemostasis and thrombin generation. The defect in primary haemostasis appears to be related to a gelatin-induced reduction in von Willebrand factor, whereas the decreased thrombin generation may be due to the dilution of coagulation factors induced by Gelofusine.

Decreased circulating levels of von Willebrand factor after intravenous administration of a rapidly degradable hydroxyethyl starch (HES 200/0.5/6) in healthy human subjects.

OBJECTIVE: Impairment of haemostasis has been described with slowly degradable medium molecular weight hydroxyethyl starch (MMW-HES), whereas rapidly degradable MMW-HES is generally considered to have no important effects on blood coagulation. This study was undertaken to investigate the effects of a rapidly degradable MMW-HES plasma substitute on primary haemostasis and blood coagulation in human subjects. DESIGN: Randomised, cross-over study. SETTING: Research unit of a university hospital. PARTICIPANTS: Nine healthy, adult male volunteers. INTERVENTIONS: A 60-min intravenous infusion of 1 l HES 200/0.5/6 (HAES-steril 6%) or 4% albumin (control). MEASUREMENT AND RESULTS: The infusion of HES resulted in decreased circulating levels of von Willebrand factor antigen (from 85+/-8% to 59+/-6% after HES vs from 80+/-7% to 69+/-8% after albumin, p<0.05) and ristocetin cofactor activity (from 93+/-4 to 67+/-4% after HES vs from 79+/-5 to 75+/-5% after albumin, p<0.01). This was associated with an impairment of in vitro platelet function as determined with the PFA-100 platelet function analyser (closure time with collagen/epinephrine from 120+/-7 to 159+/-14 s after HES vs from 121+/-7 to 137+/-10 s after albumin, p<0.05; with collagen/ADP from 88+/-3 to 116+/-9 s and from 103+/-4 to 114+/-7 s after HES and albumin, respectively, p=0.01). CONCLUSIONS: The infusion of 1 l of HES 200/0.5/6 in healthy human subjects results in moderately decreased plasma levels of von Willebrand factor associated with impairment of platelet function.

Laparoscopic detection and resection of insulinomas.

BACKGROUND: Laparoscopic ultrasonography as a diagnostic tool for the localization of islet cell tumors has been described before, but few reports on laparoscopic resection of insulinomas exist. We retrospectively reviewed the results of our experience with laparoscopic detection and the resection of insulinomas to determine its feasibility. METHODS: Between February 1996 and February 1999, 10 patients underwent operation for organic hyperinsulinism at our institution. Patient and clinical characteristics were studied retrospectively. Laparoscopic ultrasonography was performed to localize the insulinoma and then laparoscopic resection was performed. RESULTS: Eight women and 2 men underwent operation for hyperinsulinism. In 6 patients the insulinoma could be resected laparoscopically, either by enucleation (5 patients) or by resection of the pancreatic tail (1 patient). Four procedures were converted to laparotomy for the proximate location of the insulinoma to the portal vein or pancreatic duct (3 procedures) and failure to identify the insulinoma (1 procedure). The overall success rate of preoperative localization of an insulinoma with the use of various imaging techniques was 60% (6/10 patients). Laparoscopic ultrasonography could identify an insulinoma in 90% of the patients (9/10 patients). The median hospital stay was 7 days. CONCLUSIONS: Laparoscopic ultrasonography followed by laparoscopic removal of the insulinoma in patients with clinically manifested hyperinsulinism is a feasible and safe technique with low morbidity and fast postoperative recovery. Preoperative localization studies appear of limited value.

Persistence of the anti-cholinesterase soman in rats; antagonism with a non-toxic simulator of this organophosphate.

Anaesthetized, atropinized rats were poisoned with 6x LD50 soman (1,2,2,-trimethylpropyl methylphosphonofluoridate). Purified acetylcholinesterase, injected i.v. 75 min later, was rapidly inhibited, presumably by soman stored in a 'depot' from which it was gradually released. Existence of a depot is supported by the effect of a soman-simulator ('som-sim'), an organophosphonate structurally similar to soman but devoid of anti-cholinesterase activity. Som-sim can expel soman from the depot, or counteract its formation. Som-sim prophylaxis greatly enhances survival.

DNA adducts, mutant frequencies, and mutation spectra in various organs of lambda lacZ mice exposed to ethylating agents.

To investigate tissue-specific relations between DNA adducts and mutagenesis in vivo, lambda lacZ transgenic mice were treated i.p. with N-ethyl-N-nitrosourea (ENU), diethylnitrosamine (DEN), and ethyl methanesulphonate (EMS). In liver, bone marrow, and brain DNA from mice sacrificed at several time points after treatment O6-ethylguanine (O6-EtG) and N7-ethylguanine (N7-EtG) levels were determined as well as the mutant frequency (MF) in lacZ. In liver DNA of ENU- and DEN-treated mice, the bulk of O6-EtG was removed at 3 days after treatment, while the MF continued to increase thereafter. This suggests that O6-EtG is not the major premutagenic lesion in the liver. Indeed, sequence analysis of mutants showed only 24% GC-->AT transitions, consistent with the O6-EtG lesion, and 28% TA-->AT transversions, expected from O2-ethylthymine. In bone marrow after ENU treatment, a maximum mutation induction occurred at 3 days post-treatment, of which 43% were GC-->AT mutations and 22% were TA-->AT mutations. This suggests that in bone marrow O6-EtG may be a major premutagenic lesion at the 3-day time point. In liver and bone marrow, EMS treatment gave rise to a high level of N7-EtG and a low level of O6-EtG but no increase in MF. No adducts or mutation induction were observed in bone marrow of DEN-treated mice. No MF increase was observed in the brain of either ENU- or EMS-treated mice, although O6- and N7-adducts were present.