Pharmacokinetics and Pharmacodynamics of Murepavadin in Neutropenic Mouse Models.

Murepavadin (POL7080) represents the first member of a novel class of outer membrane protein-targeting antibiotics. It specifically interacts with LptD and inhibits lipopolysaccharide (LPS) transport. Murepavadin is being developed for the treatment of serious infections by Pseudomonas aeruginosa We determined the plasma protein binding and the pharmacokinetics of murepavadin in plasma and epithelial lining fluid (ELF; pulmonary) in infected animals, and we determined the exposure-response relationship. Treatment of CD-1 neutropenic mice was started 2 h after infection using murepavadin at different dosing frequencies for 24 h, and the number of CFU per lung was determined. The sigmoid maximum-effect model was used to fit the dose-response, and the pharmacodynamic index (PDI) response was used to determine the PDI values, resulting in a static effect and 1-log kill reduction. Using R2 as an indicator of the best fit, the area under the concentration-time curve for the unbound fraction of the drug (fAUC)/MIC ratio correlated best with efficacy. The mean AUC required to provide a static effect was 36.83 mg h/liter (fAUC = 8.25 mg h/liter), and that to provide a 1-log reduction was 44.0 mg h/liter (fAUC = 9.86 mg h/liter). The mean static fAUC/MIC was determined to be 27.78, and that for a 1-log reduction was 39.85. These data may serve to determine doses in humans that are likely to be efficacious.

Somatic CALR mutations in myeloproliferative neoplasms with nonmutated JAK2.

BACKGROUND: Somatic mutations in the Janus kinase 2 gene (JAK2) occur in many myeloproliferative neoplasms, but the molecular pathogenesis of myeloproliferative neoplasms with nonmutated JAK2 is obscure, and the diagnosis of these neoplasms remains a challenge. METHODS: We performed exome sequencing of samples obtained from 151 patients with myeloproliferative neoplasms. The mutation status of the gene encoding calreticulin (CALR) was assessed in an additional 1345 hematologic cancers, 1517 other cancers, and 550 controls. We established phylogenetic trees using hematopoietic colonies. We assessed calreticulin subcellular localization using immunofluorescence and flow cytometry. RESULTS: Exome sequencing identified 1498 mutations in 151 patients, with medians of 6.5, 6.5, and 13.0 mutations per patient in samples of polycythemia vera, essential thrombocythemia, and myelofibrosis, respectively. Somatic CALR mutations were found in 70 to 84% of samples of myeloproliferative neoplasms with nonmutated JAK2, in 8% of myelodysplasia samples, in occasional samples of other myeloid cancers, and in none of the other cancers. A total of 148 CALR mutations were identified with 19 distinct variants. Mutations were located in exon 9 and generated a +1 base-pair frameshift, which would result in a mutant protein with a novel C-terminal. Mutant calreticulin was observed in the endoplasmic reticulum without increased cell-surface or Golgi accumulation. Patients with myeloproliferative neoplasms carrying CALR mutations presented with higher platelet counts and lower hemoglobin levels than patients with mutated JAK2. Mutation of CALR was detected in hematopoietic stem and progenitor cells. Clonal analyses showed CALR mutations in the earliest phylogenetic node, a finding consistent with its role as an initiating mutation in some patients. CONCLUSIONS: Somatic mutations in the endoplasmic reticulum chaperone CALR were found in a majority of patients with myeloproliferative neoplasms with nonmutated JAK2. (Funded by the Kay Kendall Leukaemia Fund and others.).

Somatic SF3B1 mutation in myelodysplasia with ring sideroblasts.

BACKGROUND: Myelodysplastic syndromes are a diverse and common group of chronic hematologic cancers. The identification of new genetic lesions could facilitate new diagnostic and therapeutic strategies. METHODS: We used massively parallel sequencing technology to identify somatically acquired point mutations across all protein-coding exons in the genome in 9 patients with low-grade myelodysplasia. Targeted resequencing of the gene encoding RNA splicing factor 3B, subunit 1 (SF3B1), was also performed in a cohort of 2087 patients with myeloid or other cancers. RESULTS: We identified 64 point mutations in the 9 patients. Recurrent somatically acquired mutations were identified in SF3B1. Follow-up revealed SF3B1 mutations in 72 of 354 patients (20%) with myelodysplastic syndromes, with particularly high frequency among patients whose disease was characterized by ring sideroblasts (53 of 82 [65%]). The gene was also mutated in 1 to 5% of patients with a variety of other tumor types. The observed mutations were less deleterious than was expected on the basis of chance, suggesting that the mutated protein retains structural integrity with altered function. SF3B1 mutations were associated with down-regulation of key gene networks, including core mitochondrial pathways. Clinically, patients with SF3B1 mutations had fewer cytopenias and longer event-free survival than patients without SF3B1 mutations. CONCLUSIONS: Mutations in SF3B1 implicate abnormalities of messenger RNA splicing in the pathogenesis of myelodysplastic syndromes. (Funded by the Wellcome Trust and others.).

Somatic mutation databases as tools for molecular epidemiology and molecular pathology of cancer: proposed guidelines for improving data collection, distribution, and integration.

There are currently less than 40 locus-specific databases (LSDBs) and one large general database that curate data on somatic mutations in human cancer genes. These databases have different scope and use different annotation standards and database systems, resulting in duplicated efforts in data curation, and making it difficult for users to find clear and consistent information. As data related to somatic mutations are generated at an increasing pace it is urgent to create a framework for improving the collecting of this information and making it more accessible to clinicians, scientists, and epidemiologists to facilitate research on biomarkers. Here we propose a data flow for improving the connectivity between existing databases and we provide practical guidelines for data reporting, database contents, and annotation standards. These proposals are based on common standards recommended by the Human Genome Variation Society (HGVS) with additions related to specific requirements of somatic mutations in cancer. Indeed, somatic mutations may be used in molecular pathology and clinical studies to characterize tumor types, help treatment choice, predict response to treatment and patient outcome, or in epidemiological studies as markers for tumor etiology or exposure assessment. Thus, specific annotations are required to cover these diverse research topics. This initiative is meant to promote collaboration and discussion on these issues and the development of adequate resources that would avoid the loss of extremely valuable information generated by years of basic and clinical research.

AutoCSA, an algorithm for high throughput DNA sequence variant detection in cancer genomes.

UNLABELLED: The undertaking of large-scale DNA sequencing screens for somatic variants in human cancers requires accurate and rapid processing of traces for variants. Due to their often aneuploid nature and admixed normal tissue, heterozygous variants found in primary cancers are often subtle and difficult to detect. To address these issues, we have developed a mutation detection algorithm, AutoCSA, specifically optimized for the high throughput screening of cancer samples. AVAILABILITY: http://www.sanger.ac.uk/genetics/CGP/Software/AutoCSA.

An assessment of the in vivo efficacy of the glycogen phosphorylase inhibitor GPi688 in rat models of hyperglycaemia.

BACKGROUND AND PURPOSE: Studies in cultured hepatocytes demonstrate glycogen synthase (GS) activation with glycogen phosphorylase (GP) inhibitors. The current study investigated whether these phenomena occurred in vivo using a novel GP inhibitor. EXPERIMENTAL APPROACH: An allosteric GP inhibitor, GPi688, was evaluated against both glucagon-mediated hyperglycaemia and oral glucose challenge-mediated hyperglycaemia to determine the relative effects against GP and GS in vivo. KEY RESULTS: In rat primary hepatocytes, GPi688 inhibited glucagons-mediated glucose output in a concentration dependent manner. Additionally GP activity was reduced and GS activity increased seven-fold. GPi688 inhibited glucagon-mediated hyperglycaemia in both Wistar (65%) & obese Zucker (100%) rats and demonstrated a long duration of action in the Zucker rat. The in vivo efficacy in the glucagon challenge model could be predicted by the equation; % glucagon inhibition=56.9+34.3[log ([free plasma]/rat IC50)], r=0.921). GPi688 also reduced the blood glucose of obese Zucker rats after a 7 h fast by 23%. In an oral glucose tolerance test in Zucker rats, however, GPi688 was less efficacious (7% reduction) than a glycogen synthase kinase-3 (GSK-3) inhibitor (22% reduction), despite also observing activation (by 45%) of GS in vivo. CONCLUSIONS AND IMPLICATIONS: Although GP inhibition can inhibit hyperglycaemia mediated by increased glucose production, the degree of GS activation induced by allosteric GP inhibitors in vivo, although discernible, is insufficient to increase glucose disposal. The data suggests that GP inhibitors might be more effective clinically against fasting rather than prandial hyperglycaemic control.

Sensitivity of glycogen phosphorylase isoforms to indole site inhibitors is markedly dependent on the activation state of the enzyme.

BACKGROUND AND PURPOSE: Inhibition of hepatic glycogen phosphorylase is a potential treatment for glycaemic control in type 2 diabetes. Selective inhibition of the liver phosphorylase isoform could minimize adverse effects in other tissues. We investigated the potential selectivity of two indole site phosphorylase inhibitors, GPi688 and GPi819. EXPERIMENTAL APPROACH: The activity of glycogen phosphorylase was modulated using the allosteric effectors glucose or caffeine to promote the less active T state, and AMP to promote the more active R state. In vitro potency of indole site inhibitors against liver and muscle glycogen phosphorylase a was examined at different effector concentrations using purified recombinant enzymes. The potency of GPi819 was compared with its in vivo efficacy at raising glycogen concentrations in liver and muscle of Zucker (fa/fa) rats. KEY RESULTS: In vitro potency of indole site inhibitors depended upon the activity state of phosphorylase a. Both inhibitors showed selectivity for liver phosphorylase a when the isoform specific activities were equal. After 5 days dosing of GPi819 (37.5 micromol kg(-1)), where free compound levels in plasma and tissue were at steady state, glycogen elevation was 1.5-fold greater in soleus muscle than in liver (P < 0.05). CONCLUSIONS AND IMPLICATIONS: The in vivo selectivity of GPi819 did not match that seen in vitro when the specific activities of phosphorylase a isoforms are equal. This suggests T state promoters may be important physiological regulators in skeletal muscle. The greater efficacy of indole site inhibitors in skeletal muscle has implications for the overall safety profile of such drugs.

Phasic effects of glucose, p-hydroxymercuribenzoate, and lysophosphatidylcholine on insulin secretion from HIT cells.

Monolayer cultures of HIT cells were superfused to examine phasic insulin secretion. A biphasic pattern of insulin secretion was observed when cells were stimulated with a constant glucose concentration as low as 0.28 mM, with increasing stimulation at 0.56, 1.7, and 5.6 mM glucose. Higher glucose concentrations did not increase insulin secretion. In the absence of glucose, p-hydroxymercuribenzoate (15, 30, and 50 microM), which blocks the reacylation of lysophospholipids with arachidonic acid, also evoked a concentration-dependent biphasic release of insulin. Lysophosphatidylcholine (50, 75, and 100 micrograms/ml) also caused a concentration-dependent biphasic release of insulin in the absence of glucose. These observations were similar to those previously reported for superfused monolayer culture of rat islet cells and suggest that the HIT cell is a beta-cell line that may be valuable in the further examination of the relationships among glucose, phospholipid metabolism, and insulin secretion. The data are consistent with the hypothesis that glucose-stimulated release of lysophospholipids may be important in initiation of the biphasic pattern of glucose-stimulated insulin release.

Chloride channels regulate HIT cell volume but cannot fully account for swelling-induced insulin secretion.

Insulin-secreting pancreatic islet beta-cells possess anion-permeable Cl- channels (I(Cl,islet)) that are swelling-activated, but the role of these channels in the cells is unclear. The Cl- channel blockers 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and niflumic acid were evaluated for their ability to inhibit I(Cl,islet) in clonal beta-cells (HIT cells). Both drugs blocked the channel, but the blockade due to niflumic acid was less voltage-dependent than the blockade due to DIDS. HIT cell volume initially increased in hypotonic solution and was followed by a regulatory volume decrease (RVD). The addition of niflumic acid and, to a lesser extent, DIDS to the hypotonic solution potentiated swelling and blocked the RVD. In isotonic solution, niflumic acid produced swelling, suggesting that islet Cl- channels are activated under basal conditions. The channel blockers glyburide, gadolinium, or tetraethylammonium-Cl did not alter hypotonic-induced swelling or volume regulation. The Na/K/2Cl transport blocker furosemide produced cell shrinkage in isotonic solution and blocked cell swelling normally induced by hypotonic solution. Perifused HIT cells secreted insulin when challenged with hypotonic solutions. However, this could not be completely attributed to I(Cl,islet)-mediated depolarization, because secretion persisted even when Cl- channels were fully blocked. To test whether blocker-resistant secretion occurred via a distal pathway, distal secretion was isolated using 50 mmol/l potassium and diazoxide. Under these conditions, glucose-dependent secretion was blunted, but hypotonically induced secretion persisted, even with Cl- channel blockers present. These results suggest that beta-cell swelling stimulates insulin secretion primarily via a distal I(Cl,islet)-independent mechanism, as has been proposed for K(ATP)-independent glucose- and sulfonylurea-stimulated insulin secretion. Reverse transcriptase-polymerase chain reaction of HIT cell mRNA identified a CLC-3 transcript in HIT cells. In other systems, CLC-3 is believed to mediate swelling-induced outwardly rectifying Cl- channels. This suggests that the proximal effects of swelling to regulate cell volume may be mediated by CLC-3 or a closely related Cl- channel.

Two novel immortal pancreatic beta-cell lines expressing and secreting human islet amyloid polypeptide do not spontaneously develop islet amyloid.

Type 2 diabetes is characterized by islet amyloid deposits, which are primarily composed of the amyloidogenic human form of islet amyloid polypeptide (IAPP, amylin). The mechanism of islet amyloido-genesis is not known, but other products (e.g., apolipoprotein E and perlecan) contained within islet amyloid may be necessary. Because rodent IAPP does not form islet amyloid, the currently available beta-cell lines are not useful for studying processes involved in amyloid formation. To develop a suitable in vitro cell system for the study of islet amyloid formation, we generated two new beta-cell lines that express the amyloidogenic human IAPP. We did this by crossbreeding human IAPP transgenic mice with RIP-Tag mice that develop islet tumors and then culturing one of these islet tumors from two separate offspring of this cross. The resultant 2350-2C0 and 2511 cell lines produce human as well as mouse IAPP-like immunoreactivity (IAPP-LI) and immunoreactive insulin (IRI). Incubation of both these cell lines with 16.7 mmol/l glucose resulted in a two- to fourfold increase in human IAPP-LI, mouse IAPP-LI, and IRI secretion compared with 1.67 mmol/l glucose and the combination of 16.7 mmol/l glucose and 10 mmol/l arginine, 0.1 mmol/l 3-isobutyl-1-methylxanthine (IBMX), and 5 micromol/l carbachol induced a >50-fold increase in the release of these peptides. The omission of calcium from the above secretagogue cocktail reduced secretion of all three peptides to only two- to sixfold higher than the 16.7 mmol/l glucose condition. Perifusion with 16.7 mmol/l glucose plus 0.1 mmol/l IBMX caused a biphasic secretion of human IAPP-LI and mouse IAPP-LI, as well as IRI, in both cell lines, with the peak of the first phase being five- to sixfold higher than the prestimulated 1.67 mmol/l glucose condition. Immunoelectron microscopic inspection of both 2350-2C0 and 2511 cells after 7 days of culture did not reveal the presence of amyloid fibrils, suggesting the need for other critical components. We conclude that we have established two novel beta-cell lines that produce and secrete human IAPP in a regulated manner. These cell lines will be a useful tool to investigate the secretion of human IAPP as well as the necessity of other components for islet amyloid formation.

Decrease in anogenital distance among male infants with prenatal phthalate exposure.

Prenatal phthalate exposure impairs testicular function and shortens anogenital distance (AGD) in male rodents. We present data from the first study to examine AGD and other genital measurements in relation to prenatal phthalate exposure in humans. A standardized measure of AGD was obtained in 134 boys 2-36 months of age. AGD was significantly correlated with penile volume (R = 0.27, p = 0.001) and the proportion of boys with incomplete testicular descent (R = 0.20, p = 0.02). We defined the anogenital index (AGI) as AGD divided by weight at examination [AGI = AGD/weight (mm/kg)] and calculated the age-adjusted AGI by regression analysis. We examined nine phthalate monoester metabolites, measured in prenatal urine samples, as predictors of age-adjusted AGI in regression and categorical analyses that included all participants with prenatal urine samples (n = 85). Urinary concentrations of four phthalate metabolites [monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), and monoisobutyl phthalate (MiBP)] were inversely related to AGI. After adjusting for age at examination, p-values for regression coefficients ranged from 0.007 to 0.097. Comparing boys with prenatal MBP concentration in the highest quartile with those in the lowest quartile, the odds ratio for a shorter than expected AGI was 10.2 (95% confidence interval, 2.5 to 42.2). The corresponding odds ratios for MEP, MBzP, and MiBP were 4.7, 3.8, and 9.1, respectively (all p-values < 0.05). We defined a summary phthalate score to quantify joint exposure to these four phthalate metabolites. The age-adjusted AGI decreased significantly with increasing phthalate score (p-value for slope = 0.009). The associations between male genital development and phthalate exposure seen here are consistent with the phthalate-related syndrome of incomplete virilization that has been reported in prenatally exposed rodents. The median concentrations of phthalate metabolites that are associated with short AGI and incomplete testicular descent are below those found in one-quarter of the female population of the United States, based on a nationwide sample. These data support the hypothesis that prenatal phthalate exposure at environmental levels can adversely affect male reproductive development in humans.

Hand-assisted laparoscopic approach to renal harvest for autotransplantation.

PURPOSE: To describe a laparoscopic hand-assisted approach to renal autotransplantation that allows both harvest and transplant through the same incision. PATIENTS AND METHODS: Three patients underwent renal autotransplantation from May 2003 to April 2004, two for loin pain-hematuria syndrome and one for severe ureteral-stricture disease. Two patients underwent autotransplantation on the left and one on the right. Hand-assisted laparoscopy was planned such that inferomedial extension of the hand-port incision would provide adequate exposure of the iliac vessels for autotransplantation. RESULTS: The average operative time was 240 minutes, the warm ischemia time was 2 minutes 43 seconds, and the hospital stay was 3 days. All three patients had successful graft function by postoperative renal scan with a mean follow-up of 7.1 months. CONCLUSION: Hand-assisted laparoscopic renal harvest for autotransplantation can be completed with placement of the hand port such that transplantation can be accomplished through the same incision. As many of these patients have had multiple prior retroperitoneal operations, the intracorporeal hand can greatly facilitate these potentially difficult dissections with no added morbidity.

Contribution of L- and non-L-type calcium channels to voltage-gated calcium current and glucose-dependent insulin secretion in HIT-T15 cells.

The pharmacological properties of voltage-gated Ca current and glucose-dependent insulin secretion were determined using the HIT insulinoma line to understand the role of Ca channels in stimulus-secretion coupling. The L-type Ca channel antagonist nimodipine inhibited a maximum of 50-55% of the peak Ca current, suggesting that L- and non-L-type channels contribute to Ca current. The L-agonist BAY K 8644 increased Ca current by 155%, whereas the N-channel blocker omega-conotoxin MVIIA reversibly blocked 35% of the peak Ca current. Total block with nimodipine and MVIIA was additive. Conotoxin MVIIC did not affect HIT Ca current. Prolonged depolarizations elicited rapidly and slowly inactivating Ca currents. Nimodipine partially inhibited transient current, but fully inhibited slowly inactivating current, suggesting that the former is mediated by L- and N-channels, and the latter is mediated by L-channels. Like slowly inactivating Ca current, glucose-dependent insulin secretion was fully inhibited by nimodipine and insensitive to MVIIA. BAY K potentiated secretion and antagonized nimodipine block. These results suggest that persistent Ca current is mediated by L-channels and is strongly coupled to insulin secretion, whereas transient Ca current is mediated by L- and N-channels and is weakly coupled. Sustained Ca influx may be preferentially coupled because glucose persistently depolarizes HIT cells and inactivates more transient Ca channel pathways.

Regulation of glutamic acid decarboxylase diabetes autoantigen expression in highly purified isolated islets from Macaca nemestrina.

Macaca nemestrina, which may have larger and more numerous pancreatic islets than other species, was used for large scale islet isolation by ductal collagenase perfusion and Ficoll gradient centrifugation. The average yield was 51,000 islet equivalents per pancreas, or 8,750 islets equivalents per g. The average purity was 91%, often exceeding 95%. These are the highest reported size, purity, and yield per g of any nonautomated primate islet series. Perifusion with glucose, arginine, and isobutylmethylxanthine showed appropriate biphasic insulin secretion. Unlike that in the rat, human islet glutamic acid decarboxylase (GAD) isoform expression is restricted. However, glycemic regulation of GAD expression has been shown only in rats. We, therefore, tested hypotheses that M. nemestrina islets also have restricted GAD expression, that GAD expression in primates is stimulated by glucose, and that this stimulation remains restricted to the 64,000 mol wt (GAD65) isoform. Immunoprecipitation of labeled islet extracts showed that GAD65 expression increased 16.7 +/- 0.6-fold during high glucose in vitro culture. After controlling for observed increases in protein synthesis, specific glucose stimulation was still 4.2 +/- 0.2-fold. Specific antisera revealed no GAD67 expression under basal conditions, and isoform restriction was maintained during stimulation. Increased GAD65 synthesis thus accounts for glucose stimulation of 64K expression. These time- and concentration-dependent effects of glucose suggest that hyperglycemia increases autoantigenicity and may accelerate beta-cell destruction in primates, supporting a role for beta-cell rest in insulin-dependent diabetes mellitus prevention.

A medical evaluation of the use of qat in North Yemen.

The data presented in this paper examine the frequent statements that the regular use of the drug qat by the people of North Yemen is harmful to their health. The research strategy employed performance of blind physical examinations as well as extensive interviews with 335 females and 371 males in and around the cities of Sanaa, Taiz and Hodeida who had been selected using a quota sample. The sample was classified into heavy, light and non-chewers of the qat plant, and systematic comparisons were made. In general, few diseases or conditions occurred with enough frequency to permit detailed analysis and fewer yet were associated with qat-use. Where associations occurred, differences by sex were often strong. Conditions most strongly associated with use by both sexes were histories of gastritis and insomnia, and the general body system groupings of gastrointestinal disorders. In males the strongest associations were with the histories of anorexia, constipation, insomnia and headaches, as well as the general history of respiratory difficulties. In females strong associations were seen between qat-use and the diagnosis of acute gastritis, and histories of jaundice, bronchitis and hepatic diseases. When effects of age and residence were corrected for by Mantel-Haenszel odds ratios on these items, some of the associations were diminished even further. In general, remarkably few of the allegations regarding the direct effects of qat-use on health by Western visitors to Yemen were supported by this study.

Catheter knotting in a catheterizable urinary reservoir.

An 11-year-old boy with bladder extrophy was treated ultimately with an ileocystoplasty and a catheterizable stoma. In attempting to drain his bladder via intermittent catheterization, the catheter became lodged. This case details the surgical treatment of a knotted catheter in an urinary reservoir.

The optimal approach for management of metachronous hernias in children: a decision analysis.

PURPOSE: Up to 30% of children undergoing unilateral hernia repair will later get a hernia on the contralateral side that requires repair. Three approaches have been used to address the potential for development of a metachronous hernia: (1) observation and repair of a contralateral hernia only if it later becomes apparent, (2) routine contralateral groin exploration, and (3) laparoscopy to evaluate the contralateral groin for a potential hernia. The purpose of this study was to use decision analysis to determine which approach resulted in the lowest morbidity, mortality, and cost. METHODS: A decision tree was constructed for the management of metachronous hernias that accounted for the occurrence of both nonincarcerated and incarcerated metachronous hernias. Baseline values were estimated from recent reports in the literature. Total charges for each approach were obtained from available hospital records and were used to estimate cost. RESULTS: Observation was favored over laparoscopy and laparoscopy over routine exploration with respect to preventing spermatic cord injury and preserving future fertility. Although a second operation may be required when observation is used, this approach was associated with only a small increase in anesthesia-related complications (1 in 17,847), cardiac arrests (1 in 62,500), and death (1 in 312,500). Although observation was the favored approach with respect to cost, laparoscopy was less expensive when the expected incidence of metachronous hernias was high. CONCLUSIONS: Observation is the preferred approach to metachronous hernias because it results in the lowest incidence of injury and cost for most patients and is associated with a minimal increase in anesthesia-related morbidity and mortality. Laparoscopy may be advantageous for patients at high risk for development of a contralateral hernia. As a strategy for preventing metachronous hernias without consideration for injury or cost, routine exploration should be limited to situations in which laparoscopy cannot be performed because of small patient size or a preference for spinal anesthesia.

Testicular histology after transparenchymal fixation using polytetrefluoroethylene suture: an animal model.

BACKGROUND/PURPOSE: The optimal surgical technique for orchiopexy is controversial. Studies have shown that adequate fixation can be obtained using a subdartos pouch alone; however, transparenchymal suture fixation with a permanent suture frequently is used to provide additional security and for the treatment and prevention of testicular torsion. In previous studies, the suture has been placed through the tunica albuginea. This could have a detrimental effect on future spermatogenesis. Polypropylene has been shown to have the least histological change and is considered to be the suture of choice. However, polypropylene is a stiff suture and can be disconcerting for the patient when left in place. Polytetrafluoroethylene (PTFE) is a soft, permanent suture used widely in vascular surgery because of its handling characteristics. In this study, the authors compare the histological changes caused by PTFE and polypropylene. METHODS: Bilateral orchiopexies were performed in 36 Sprague-Dawley rats. All rats were 27 to 31 days old and weighed 75 to 100 g at the time of orchiopexy. The animals were divided into 3 groups receiving polypropylene and PTFE, silk and PTFE, or polypropylene and silk. After 30 days, all rats were killed, and the testes were harvested. The testes were step sectioned and examined for histological changes. These changes were graded by a pathologist in a blinded fashion. RESULTS: The data obtained were statistically analyzed. The superficial histological changes associated with transparenchymal fixation by polypropylene, PTFE, and silk were significantly different, but the parenchymal changes were not. CONCLUSIONS: PTFE causes no greater histological change than polypropylene. In light of the PTFE's softness and superior handling characteristics, the authors recommend the use of PTFE when a permanent suture is used in orchiopexy.

Coordinating California's efforts to promote waste to alcohol production.

Alcohol fuels produced from biomass can improve air quality, enhance energy security, create employment opportunities, and reduce waste disposal problems. Opportunities in California exist to produce alcohols from waste streams from various sectors of the economy. Government agencies have promoted waste-to-alcohol activities, but efforts have been inconsistent and intermittent. Often these efforts have been hindered by contradictory but mandate-driven policies. A prudent approach to coordinate statewide efforts includes the development of an integrated statewide policy to examine barriers that impede private sector business efforts to produce alcohols from biomass. A multi-agency task force to promote research, development, commercialization, and marketing efforts for biomass-produced alcohols is desirable.