Noninvasive biomagnetic detection of intestinal slow wave dysrhythmias in chronic mesenteric ischemia.

Chronic mesenteric ischemia (CMI) is a challenging clinical problem that is difficult to diagnose noninvasively. Diagnosis early in the disease process would enable life-saving early surgical intervention. Previous studies established that superconducting quantum interference device (SQUID) magnetometers detect the slow wave changes in the magnetoenterogram (MENG) noninvasively following induction of mesenteric ischemia in animal models. The purpose of this study was to assess functional physiological changes in the intestinal slow wave MENG of patients with chronic mesenteric ischemia. Pre- and postoperative studies were conducted on CMI patients using MENG and intraoperative recordings using invasive serosal electromyograms (EMG). Our preoperative MENG recordings showed that patients with CMI exhibited a significant decrease in intestinal slow wave frequency from 8.9 ± 0.3 cpm preprandial to 7.4 ± 0.1 cpm postprandial (P < 0.01) that was not observed in postoperative recordings (9.3 ± 0.2 cpm preprandial and 9.4 ± 0.4 cpm postprandial, P = 0.86). Intraoperative recording detected multiple frequencies from the ischemic portion of jejunum before revascularization, whereas normal serosal intestinal slow wave frequencies were observed after revascularization. The preoperative MENG data also showed signals with multiple frequencies suggestive of uncoupling and intestinal ischemia similar to intraoperative serosal EMG. Our results showed that multichannel MENG can identify intestinal slow wave dysrhythmias in CMI patients.

Fibroblast growth factor 23 (FGF23) and alpha-klotho stimulate osteoblastic MC3T3.E1 cell proliferation and inhibit mineralization.

Elevated serum levels of the phosphate-regulating hormone fibroblast growth factor 23 (FGF23) are found in patients with phosphate wasting diseases and chronic kidney disease-mineral and bone disorder (CKD-MBD). These diseases are associated with rickets and renal osteodystrophy, respectively. FGF23 is secreted from osteoblastic cells and signals through FGFRs, membrane coreceptor alpha-Klotho (Klotho), and, possibly, a circulating form of Klotho. Despite the absence of detectable Klotho on osteoblastic cells, studies have suggested that forced FGF23 expression in osteoblasts inhibited mineralization. Thus, we examined the effects of exogenously applied FGF23 on osteoblastic MC3T3.E1 cell proliferation and differentiation, with and without soluble Klotho. MC3T3.E1 cells were cultured in osteoblast differentiation medium, supplemented with FGF23 (0.1-1,000 ng/mL), Klotho (50 ng/mL), the combination FGF23 + Klotho, and FGF2 (100 ng/mL) as a control. Neither FGF23 nor Klotho exposure affected proliferation of day 4 growth phase cells or mineralization of day 14 cultures. In contrast, FGF23 + Klotho resulted in inhibition of mineralization and osteoblast activity markers at day 14, and a slight, reproducible induction of proliferation. Inhibition of FGFR1, but not FGFR2 or FGFR3, completely restored FGF23 + Klotho-induced inhibition of alkaline phosphatase (ALP) activity at day 7. ALP activity was partially restored by the MAPK inhibitor U0126 but not inhibitors p38 and P13K. Thus, soluble Klotho enables FGF23 signaling in MC3T3.E1 cells, likely through FGFR 1(IIIc). Elevated FGF23 actions, in part, appear to parallel FGF2 with lower potency. In addition to affecting bone via indirect phosphate wasting pathways, supraphysiological FGF23 and soluble Klotho may directly impact bone in diseases with elevated FGF23 levels.

Improving the accuracy of ultrafast ligand-based screening: incorporating lipophilicity into ElectroShape as an extra dimension.

In a previous paper, we presented the ElectroShape method, which we used to achieve successful ligand-based virtual screening. It extended classical shape-based methods by applying them to the four-dimensional shape of the molecule where partial charge was used as the fourth dimension to capture electrostatic information. This paper extends the approach by using atomic lipophilicity (alogP) as an additional molecular property and validates it using the improved release 2 of the Directory of Useful Decoys (DUD). When alogP replaced partial charge, the enrichment results were slightly below those of ElectroShape, though still far better than purely shape-based methods. However, when alogP was added as a complement to partial charge, the resulting five-dimensional enrichments shows a clear improvement in performance. This demonstrates the utility of extending the ElectroShape virtual screening method by adding other atom-based descriptors.

Blockade of Dickkopf (DKK)-1 induces fusion of sacroiliac joints.

OBJECTIVE: To study whether Dickkopf (DKK)-1, an inhibitor of wingless (Wnt) signalling, is involved in the fusion of sacroiliac joints. METHODS: Mice transgenic for tumour necrosis factor (TNFtg mice), which develop bilateral sacroiliitis, were treated with vehicle, anti-TNF antibody or anti-DKK1 antibody. Sacroiliac joints were analysed for histological signs of inflammation, bone erosion, osteoclast formation and ankylosis. Moreover, expression of collagen type X, beta-catenin and DKK-1 was assessed by immunohistochemistry. RESULTS: There were no signs of spontaneous ankylosis of the sacroiliac joints in TNFtg mice. TNF blockade effectively reduced inflammation, bone erosion and osteoclast numbers in the sacroiliac joints, but did not lead to ankylosis. Blockade of DKK1 had no effect on inflammatory signs of sacroiliitis, but significantly reduced bone erosions and osteoclast counts. Moreover, DKK1 blockade promoted expression of collagen type X, the formation of hypertrophic chondrocytes and ankylosis of sacroiliac joints. CONCLUSION: DKK1 influences inflammatory remodelling of sacroiliac joints by prevention of joint ankylosis. This may indicate an important role of the Wnt signalling pathway in the structural bone changes of axial joint disease. Although this model does not reflect the entire spectrum of ankylosing spondylitis in humans, it helps to explain the pathophysiological processes of sacroiliac joint ankylosis, which is a hallmark of the spondyloarthritides.

Molecular alignment using multipole moments.

Molecules can be aligned on the basis of their computed electrical multipole moments. This description of molecular electrostatics is proposed and evaluated for similarity applications. It accurately models the charge distribution in compounds with medicinal chemistry interest where electrostatics is known to play an important role in their interaction with the target.

ElectroShape: fast molecular similarity calculations incorporating shape, chirality and electrostatics.

We present ElectroShape, a novel ligand-based virtual screening method, that combines shape and electrostatic information into a single, unified framework. Building on the ultra-fast shape recognition (USR) approach for fast non-superpositional shape-based virtual screening, it extends the method by representing partial charge information as a fourth dimension. It also incorporates the chiral shape recognition (CSR) method, which distinguishes enantiomers. It has been validated using release 2 of the Directory of useful decoys (DUD), and shows a near doubling in enrichment ratio at 1% over USR and CSR, and improvements as measured by Receiver Operating Characteristic curves. These improvements persisted even after taking into account the chemotype redundancy in the sets of active ligands in DUD. During the course of its development, ElectroShape revealed a difference in the charge allocation of the DUD ligand and decoy sets, leading to several new versions of DUD being generated as a result. ElectroShape provides a significant addition to the family of ultra-fast ligand-based virtual screening methods, and its higher-dimensional shape recognition approach has great potential for extension and generalisation.

Anomalous retinal pathways in the Siamese cat: an inadequate substrate for normal bioncular vision.

All major retinal pathways in the Siamese cat are abnormal, with almost total crossing of the projections to the pretectum and superior colliculus. These projections represent a marked disruption in the customary neural substrate for binocular vision, which implies a consequent impairment in stereoscopic depth perception. Crossed eyes, commonly seen in the Siamese cat, may therefore arise from a neuroanatomical defect in the primary visual pathways.

Bluetongue virus infection: pathologic responses of nervous systems in sheep and mice.

Lesions caused by bluetongue virus infection of the central nervous systems of sheep and mice vary with age of the host. The character of the lesions appears to be influenced by the stage of immunological maturity of the infected animals.

Membrane changes in a single photoreceptor cause associative learning in Hermissenda.

Single type B photoreceptors in intact, restrained Hermissenda were impaled with a microelectrode and exposed to either paired or unpaired presentations of light and depolarizing current to simulate natural stimulus effects during conditioning with light and rotation. Paired, but not unpaired, stimulus presentations produced cumulative depolarization and increased input resistance in type B cells. These membrane changes are similar to those observed after pairings of light and rotation are administered to either intact animals or isolated nervous systems or when light is paired with electrical stimulation of the vestibular system in isolated nervous systems. One and two days after treatment, pairing- and light-specific suppression of phototactic behavior was observed in recovered animals. These findings indicate that the membrane changes of type B cells produced by pairing light with current injections cause acquisition of the learned behavior.

Mutations in the LKB1 tumour suppressor are frequently detected in tumours from Caucasian but not Asian lung cancer patients.

Somatic mutations of LKB1 tumour suppressor gene have been detected in human cancers including non-small cell lung cancer (NSCLC). The relationship between LKB1 mutations and clinicopathological characteristics and other common oncogene mutations in NSCLC is inadequately described. In this study we evaluated tumour specimens from 310 patients with NSCLC including those with adenocarcinoma, adenosquamous carcinoma, and squamous cell carcinoma histologies. Tumours were obtained from patients of US (n=143) and Korean (n=167) origin and screened for LKB1, KRAS, BRAF, and EGFR mutations using RT-PCR-based SURVEYOR-WAVE method followed by Sanger sequencing. We detected mutations in the LKB1 gene in 34 tumours (11%). LKB1 mutation frequency was higher in NSCLC tumours of US origin (17%) compared with 5% in NSCLCs of Korean origin (P=0.001). They tended to occur more commonly in adenocarcinomas (13%) than in squamous cell carcinomas (5%) (P=0.066). LKB1 mutations associated with smoking history (P=0.007) and KRAS mutations (P=0.042) were almost mutually exclusive with EGFR mutations (P=0.002). The outcome of stages I and II NSCLC patients treated with surgery alone did not significantly differ based on LKB1 mutation status. Our study provides clinical and molecular characteristics of NSCLC, which harbour LKB1 mutations.

Dynamics of conserved waters in human Hsp90: implications for drug design.

The flexibility of a promising protein target, human heat shock protein 90 (Hsp90), is investigated by molecular dynamics simulations. These simulations focus on: (i) the interactions between the protein and conserved water molecules; and (ii) the interactions of the ligand PU3, the conserved water molecules and the protein. This is followed by a virtual screening docking study of the PU3 family of compounds and Hsp90 incorporating several conserved water molecules.

Sclerostin and DKK1 Inhibition Preserves and Augments Alveolar Bone Volume and Architecture in Rats with Alveolar Bone Loss.

Alveolar bone is a mechanosensitive tissue that provides structural support for teeth. Alveolar bone loss is common with aging, menopause, tooth loss, and periodontitis and can lead to additional tooth loss, reduced denture fixation, and challenges in placing dental implants. The current studies suggest that sclerostin and DKK1, which are established osteocyte-derived inhibitors of bone formation, contribute to alveolar bone loss associated with estrogen ablation and edentulism in rats. Estrogen-deficient ovariectomized rats showed significant mandibular bone loss that was reversed by systemic administration of sclerostin antibody (SAB) alone and in combination with DKK1 antibody (DAB). Osteocytes in the dentate and edentulous rat maxilla expressed Sost (sclerostin) and Dkk1 (DKK1) mRNA, and molar extraction appeared to acutely increase DKK1 expression. In a chronic rat maxillary molar extraction model, systemic SAB administration augmented the volume and height of atrophic alveolar ridges, effects that were enhanced by coadministering DAB. SAB and SAB+DAB also fully reversed bone loss that developed in the opposing mandible as a result of hypo-occlusion. In both treatment studies, alveolar bone augmentation with SAB or SAB+DAB was accompanied by increased bone mass in the postcranial skeleton. Jaw bone biomechanics showed that intact sclerostin-deficient mice exhibited stronger and denser mandibles as compared with wild-type controls. These studies show that sclerostin inhibition, with and without DKK1 coinhibition, augmented alveolar bone volume and architecture in rats with alveolar bone loss. These noninvasive approaches may have utility for the conservative augmentation of alveolar bone.

Epidermal growth factor receptor activity mediates renal cyst formation in polycystic kidney disease.

A consistent phenotype observed in both human patients and several different mouse models of autosomal recessive polycystic kidney disease (ARPKD) is an increased activity of the epidermal growth factor receptor (EGFR) in the affected kidneys. To determine whether this increased activity of the EGFR is a functional event that is directly part of the disease pathway of renal cyst formation, we used a genetic approach to introduce a mutant EGFR with decreased tyrosine kinase activity into a murine model of ARPKD. We found that the modified form of the EGFR could block the increase in EGFR-specific tyrosine kinase activity that normally accompanies the development of renal cysts, and this correlated with an improvement in kidney function and a substantial decrease in cyst formation in the collecting ducts. These results suggest that changes in the expression of the EGFR contribute to the formation of cysts in the collecting ducts, and that drugs that target the tyrosine kinase activity of the EGFR may potentially be therapeutic in ARPKD.

Interaction between the product of the breast cancer susceptibility gene BRCA2 and DSS1, a protein functionally conserved from yeast to mammals.

Germ line mutations in the breast cancer susceptibility gene BRCA2 predispose to early-onset breast cancer, but the function of the nuclear protein encoded by the gene is ill defined. Using the yeast two-hybrid system with fragments of human BRCA2, we identified an interaction with the human DSS1 (deleted in split hand/split foot) gene. Yeast and mammalian two-hybrid assays showed that DSS1 can associate with BRCA2 in the region of amino acids 2472 to 2957 in the C terminus of the protein. Using coimmunoprecipitation of epitope-tagged BRCA2 and DSS1 cDNA constructs transiently expressed in COS cells, we were able to demonstrate an association. Furthermore, endogenous BRCA2 could be coimmunoprecipitated with endogenous DSS1 in MCF7 cells, demonstrating an in vivo association. Apparent orthologues of the mammalian DSS1 gene were identified in the genome of the yeasts Schizosaccharomyces pombe and Saccharomyces cerevisiae. Yeast strains in which these DSS1-like genes were deleted showed a temperature-sensitive growth phenotype, which was analyzed by flow cytometry. This provides evidence for a link between the BRCA2 tumor suppressor gene and a gene required for completion of the cell cycle.

From diatomics to drugs and dividends.

The path from diatomic molecule spectroscopy to molecular modelling and drug discovery is described, along with aspects of the commercialisation of research. It is a history tightly coupled with the advances in computers over the past 50 years, but with a future full of opportunity.

A comparison of 399 open and 568 laparoscopic gastric bypasses performed during a 4-year period.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass surgery (RYGB) was introduced at the authors' institution 5 years ago. The authors analyzed the short- and long-term results of this procedure compared with those for the same procedure using the laparotomy approach over the same period. METHODS: Retrospective analysis of a prospectively collected bariatric database used the outcome end points used by the American Society of Bariatric Surgery (ASBS) and the American College of Surgeons (ACS) in their center of excellence programs. RESULTS: From January 2001 to July 2005, 568 laparoscopic and 399 open gastric bypasses were performed at Vanderbilt University. The patients were from the same bariatric surgery program and therefore received the same pre- and postoperative care. The hospital length of stay in the laparoscopic group was significantly shorter (2.5 +/- 2.4 days) than in the open group (3.7 +/- 3.7 days; p = 0.001). The procedure time was significantly shorter in the laparoscopic group (164 +/- 50 min) than in the open group (195 +/- 50 min; p = 0.0001). The follow-up assessment response at 2 years was 76.6%. At 2 years, the excess weight loss (EWL) was significantly greater in the laparoscopic group (71.3% +/- 18.4%) than in the open group (67.3% +/- 15.3%; p = 0.03). The wound infection rate was significantly higher in open group (9.2%) than in the laparoscopic group (1.7%; p = 0.001). There was no significant difference in 30-day mortality: open (0.50%) versus laparoscopic (0.17%; p = 0.371). There was no significant difference in the 30-day reoperation rate between the open (2.4%) and laparoscopic (2.6%; p = 0.705) groups. The 30-day readmission rate was similar in the open (5.0%) and laparoscopic (5.2%; p = 0.852) groups, as was the rate of leakage from the gastrojejunostomy in the open (0.50%) and laparoscopic (0.35%; p = 0.127) groups. The conversion rate from laparoscopic procedure to laparotomy was 1.7%. CONCLUSION: In the authors' institution, a laparoscopic bariatric surgery program with a very low rate of morbidity and mortality has been introduced. Operative time, hospital stay, and wound complications are reduced with the laparoscopic approach. The laparoscopic and open procedures are equally safe, with equivalent 30-day mortality, readmission, reoperation, and gastrojejunostomy leakage rates.

The role of the surgeon in the evolution of flexible endoscopy.

Several cultures, including the Egyptians, Greeks, Romans, and Arabs, made attempts to view accessible human body cavities using a variety of instruments such as spatulas and specula. The first endoscope was created in 1806 when Phillip Bozzini, a German-born urologist, constructed the lichtleiter, which used concave mirrors to reflect candlelight through an open tube into the esophagus, bladder, or rectum. Maximilian Carl-Friedrich Nitze, another German urologist, produced the first usable cystoscope in 1877 by using series of lenses to increase magnification. He was also the first to place light inside the organ of interest to aid visualization. In 1880 Mikulicz made the first gastroscope using a system similar to Nitze's cystoscope. Modern endoscopy was born with the introduction of the fiberoptic endoscope in the late 1950s. Over the ensuing 50 years endoscopy revolutionized many aspects of the surgeon's practice. Endoscopy can now be used to diagnose and often treat gastrointestinal cancer, hemorrhage, obstruction, and inflammatory conditions. This review was initiated by the SAGES Flexible Endoscopy Committee to chronicle the role of the surgeon in the development and introduction of flexible endoscopy into clinical practice, historically and in contemporary surgery. Flexible endoscopy evolved out of surgeons' need to overcome diagnostic and therapeutic challenges. There have been many recent technological advances that facilitate endoluminal therapies, and flexible endoscopy is now traversing new ground. Surgeons have been major contributors in the development of all aspects of endoscopy. There is a continually expanding list of therapeutic options available to patients. The difficult questions of which procedure, on which patient, and when can be answered best by the surgeon versed in endoscopic, laparoscopic, and open surgical techniques.

Risk of secondary hyperparathyroidism after laparoscopic gastric bypass surgery in obese women.

BACKGROUND: Metabolic bone disease is a potential complication of bariatric surgery. The aims of our study were to evaluate the effects of laparoscopic gastric bypass on calcium and vitamin D metabolism, and to identify patients at high risk to develop secondary hyperparathyroidism (HPT). METHODS: Serum calcium, alkaline phosphatase, intact parathyroid hormone (PTH), and 25-hydroxy (OH) vitamin D were measured at 3, 6, 12, and 24 months after laparoscopic gastric bypass in a cohort of morbidly obese women. Logistic regression was used in both univariate and multivariate models to identify independent preoperative variables associated with secondary HPT. RESULTS: The study enrolled 193 morbidly obese women. During the 2-year follow-up period, the incidence of elevated PTH levels (>65 pg/ml) was 53.3%. The mean time elapsed between surgery and detection of secondary HPT was 9.1 months (range, 3-24 months). Vitamin D deficiency was observed in 39 patients (20.2%). On univariate analysis, the preoperative factors associated with secondary HPT were race (high PTH levels were detected in 70% of African Americans versus 50% of Caucasians; p < 0.05), preoperative body mass index (BMI; high PTH: 52.5 +/- 10.8 versus normal PTH: 48.9 +/- 7.5 kg/m2; p < 0.01), and age (high PTH: 44.9 +/- 9.2 versus normal PTH: 42.3 +/- 9 years, p < 0.05). Race and age remained independent risk factors for secondary HPT in the multivariate logistic regression model after adjusting for the covariate Roux-limb length. African Americans were at more than 2.5 times greater risk to develop secondary HPT as Caucasian (RR 2.5; 95% CI: 1.03-6.17, p < 0.05). Patients older than 45 years were at 1.8 times higher risk of developing secondary HPT as their younger counterparts (RR 1.8; 95% CI: 1.01-3.32, p < 0.05). CONCLUSIONS: Morbidly obese women have a high incidence of elevated PTH levels after gastric bypass surgery. Low vitamin D levels did not constitute the only reason behind this finding. African-American women and women older than 45 years of age were at significantly higher risk of developing secondary HPT. In these populations, aggressive supplementation with calcium citrate and vitamin D should be implemented.

Prevalence and seasonal changes in the population of gastrointestinal nematodes of small ruminants in the semi-arid zone of north-eastern Nigeria.

A survey was carried out to determine the prevalence and seasonal abundance of the egg and adult stages of nematode parasites of sheep and goats in the semi-arid zone of north-eastern Nigeria between January and December 2002. Faecal samples collected from 102 sheep and 147 goats and examined by the modified McMaster technique using saturated solution of sodium chloride as the floating medium revealed that 44 (43.1%) and 82 (55.8%) of the samples, respectively, contained at least one nematode egg type. Three nematode egg types were recovered with strongyle egg type (22.5% in sheep and 35.4% in goats) being the most prevalent followed, respectively, by Trichuris (5.9% in sheep and 4.1% in goats) and Strongyloides (4.9% in sheep and 4.1% in goats) egg types. Mean faecal egg counts were generally moderate in both sheep (1052+/-922 strongyle, 1000+/-590 Strongyloides and 380+/-110 Trichuris eggs, respectively, per g of faeces) and goats (2092+/-3475 strongyle, 958+/-854 Strongyloides and 683+/-512 Trichuris eggs, respectively, per g of faeces) and showed the same trend irrespective of the age or sex of the animals. The prevalence and counts of strongyle nematode eggs showed a definite seasonal sequence that corresponded with the rainfall pattern in the study area during the period. In both sheep and goats, counts of strongyle egg type increased with the rains and reached peak levels at about the peak of the rainy season in September. The other egg types encountered during the study did not show much variation with the season of the year. Out of the 45 sheep and 75 goats examined at necropsy, 27 (60%) and 39 (52%), respectively, contained adult nematode species. Seven genera of adult nematodes including Strongyloides, Trichostrongylus, Haemonchus, Trichuris, Cooperia, Oesophagostomum and Bunostomum species were encountered during the study. Bunostomum species were recorded only in sheep. Adult worm burdens were generally low and showed seasonal variation that corresponded with the rainfall pattern in the study area during the period. Haemonchus and Trichostrongylus species attained peak counts together in both goats (June) and sheep (August). Strongyloides species were encountered throughout the year in both sheep and goats irrespective of the season. Other genera of nematodes encountered occurred in very low numbers and did not allow any meaningful comparison of seasonal sequence. The results suggest that Haemonchus, Trichostrongylus and Strongyloides species may be the major contributors to small ruminant helminthiasis in the study area.