Improved detection of hepatitis C virus antibodies in high-risk populations.

Sera from 483 patients at high (group 1, n = 313) and lower (group 2, n = 170) risk for exposure to hepatitis C were tested for antibodies to hepatitis C using first-generation (c100-3) and second-generation enzyme-linked immunosorbent assays and four-antigen recombinant immunoblot assay. The second-generation enzyme-linked immunosorbent assay and nitrocellulose-based immunoblot assay differ from c100-3-based systems in the addition of expression products from the NS3/NS4 (c33c, c200) and putative nucleocapsid (c22-3) region of the hepatitis C genome. In group 1, the sensitivity of detection of hepatitis C antibodies was 45%, 55% and 46% by the first- and second-generation enzyme-linked immunosorbent assays and recombinant immunoblot assay, respectively. In group 2, antibodies were detected by each test system in 26%, 32% and 7% of patients, respectively. Most sera (99%) reactive with the first-generation enzyme-linked immunosorbent assay were reactive with the second-generation enzyme-linked immunosorbent assay (in group 1, 89% of these specimens demonstrated reactivity to at least one antigen with the immunoblot assay, compared with only 31% in group 2). An additional 12% (group 1) and 6% (group 2) of specimens demonstrated reactivity with the second-generation enzyme-linked immunosorbent assay only (of these, 75% [group 1] and 9% [group 2] demonstrated reactivity to at least one antigen with the immunoblot assay). Ninety-eight percent of specimens not reactive with both enzyme-linked immunosorbent assay test systems were also nonreactive by recombinant immunoblot assay.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of 1 Hz rTMS preconditioned by tDCS on gait kinematics in Parkinson’s disease

Hypokinetic gait is a common and very disabling symptom of Parkinson’s disease (PD). Repetitive transcranial magnetic stimulation (rTMS) over the motor cortex has been used with variable effectiveness to treat hypokinesia in PD. Preconditioning rTMS by transcranial direct current stimulation (tDCS) may enhance its effectiveness to treat hypokinetic gait in PD. Three-dimensional kinematic gait analysis was performed (1) prior to, (2) immediately after and (3) 30 min after low-frequency rTMS (1 Hz, 900 pulses, 80 % of resting motor threshold) over M1 contralateral to the more affected body side preconditioned by (1) cathodal, (2) anodal or (3) sham tDCS (amperage: 1 mA, duration: 10 min) in ten subjects with PD (7 females, mean age 63 ± 9 years) and ten healthy subjects (four females, mean age 50 ± 11 years). The effects of tDCS-preconditioned rTMS on gait kinematics were assessed by the following parameters: number of steps, step length, stride length, double support time, cadence, swing and stance phases. Our data suggest a bilateral improvement of hypokinetic gait in PD after 1 Hz rTMS over M1 of the more affected body side preceded by anodal tDCS. In contrast, 1 Hz rTMS alone (preceded by sham tDCS) and 1 Hz rTMS preceded by cathodal tDCS were ineffective to improve gait kinematics in PD. In healthy subjects, gait kinematics was unaffected by either intervention. Preconditioning motor cortex rTMS by tDCS is a promising approach to treat hypokinetic gait in PD.     

Electrohydraulic lithotripsy in 111 patients: a safe and effective therapy for difficult bile duct stones

BACKGROUND: Choledocholithiasis and intrahepatic bile duct stones pose a significant health hazard, especially in the elderly. The large stone not removable with conventional endoscopic techniques, can be effectively and safely managed with electrohydraulic lithotripsy (EHL). METHODS: This study is a retrospective review of consecutive patients at the Wellesley Central Hospital and St. Michael's Hospital, who underwent peroral endoscopic fragmentation of bile duct stones with EHL under direct cholangioscopic control using a "mother-baby" endoscopic system between October 1990 and March 2002. RESULTS: To date, 111 patients have been analyzed. Of the 111 patients reviewed, 94 patients have had complete records and were included in this study. Mean follow-up was 26.2 months (range 0-80). Prior to EHL, 93 of 94 patients (99%) had endoscopic retrograde cholangiopancreatography (ERCP) and failed standard stone extraction techniques (mean 1.9 ERCPs/patient, range 0-5). Indications for EHL were large stones (81 patients) or a narrow caliber bile duct below a stone of average size (13 patients). Successful fragmentation (61 complete, 28 partial) was achieved in 89 of 93 patients (96%) (1 patient was excluded from analysis due to a broken endoscope). Fragmentation failures were due to targeting problems (2 patients) and hard stones (2 patients). Seventy-six percent of patients required 1 EHL session, 14% required 2 sessions, and 10% required 3 or more. All patients with successful stone fragmentation required post-EHL balloon or basket extraction of fragments. Complications included: cholangitis and/or jaundice (13 patients); mild hemobilia (1 patient); mild post-ERCP pancreatitis (1 patient); biliary leak (1 patient); and bradycardia (1 patient). There were no deaths related to EHL. Final stone clearance was achieved in 85 of 94 patients (90%). CONCLUSIONS: EHL via peroral endoscopic choledochoscopy is a highly successful and safe technique for use in the management of difficult choledocholithiasis and intrahepatic stones. This study has shown a stone fragmentation rate of 96% (89 of 93 patients), and a final stone clearance rate of 90% (85 of 94 patients).     

Defective propagation of signals generated by sympathetic nerve stimulation in the liver of connexin32-deficient mice.

The gap junctional protein connexin32 is expressed in hepatocytes, exocrine pancreatic cells, Schwann cells, and other cell types. We have inactivated the connexin32 gene by homologous recombination in the mouse genome and have generated homozygous connexin32-deficient mice that were viable and fertile but weighed on the average approximately 17% less than wild-type controls. Electrical stimulation of sympathetic nerves in connexin32-deficient liver triggered a 78% lower amount of glucose mobilization from glycogen stores, when compared with wild-type liver. Thus, connexin32-containing gap junctions are essential in mouse liver for maximal intercellular propagation of the noradrenaline signal from the periportal (upstream) area, where it is received from sympathetic nerve endings, to perivenous (downstream) hepatocytes. In connexin32-defective liver, the amount of connexin26 protein expressed was found to be lower than in wild-type liver, and the total area of gap junction plaques was approximately 1000-fold smaller than in wild-type liver. In contrast to patients with connexin32 defects suffering from X chromosome-linked Charcot-Marie-Tooth disease (CMTX) due to demyelination in Schwann cells of peripheral nerves, connexin32-deficient mice did not show neurological abnormalities when analyzed at 3 months of age. It is possible, however, that they may develop neurodegenerative symptoms at older age.     

Suppressor factor from a T cell hybrid inhibits delayed-type hypersensitivity responses to azobenzenearsonate.

By using polyethylene glycol 1540, BW5147 AKR T lymphoma cells were fused with splenocytes from A/J mice treated so as to induce suppressor T cells specific for azobenzenearsonate (ABA). Of 576 microwells originally seeded, 132 demonstrated growing cell clones, 4 of which produced an ABA-binding supernatant factor. When tested in vivo for suppression of delayed-type hypersensitivity to ABA, two of these cell lines, A4 and F12, were shown to produce suppressive supernatant factors. Fluorescence analysis of the F12 cells with appropriate antisera demonstrated this T cell hybrid to be Thy 1.2+, Lyt 1+,2-, and surface immunoglobulin negative, the surface marker phenotype of conventional ABA-specific suppressor T cells. This cloned suppressor cell line, F12, produces a culture supernatant factor that is suppressive at dilutions up to 1:100 and has provided material for genetic and immunochemical analysis.     

Are action and perception in near and far space additive or interactive factors?

Functional imaging has revealed differential neural mechanisms underlying action directed toward near or far space. Because some neuropsychological studies of patients with visuospatial neglect failed to show near/far dissociations with perceptual tasks, we investigated whether action and perception elicit distinct cerebral representations in near and far space. We measured regional cerebral blood flow with positron emission tomography in normal volunteers who performed manual line bisection (action) and made line bisection judgments (perception). Stimuli were presented in near space or far space. Far space presentation enhanced activations in occipital cortex extending into the medial occipitotemporal cortex bilaterally, while near space presentation enhanced left occipital-parietal, parietal, and premotor cortex activity. Manual bisection activated the extrastriate, superior parietal, and premotor cortex bilaterally, while bisection judgments activated the right inferior parietal cortex, anterior cingulate, right dorsolateral prefrontal cortex, and extrastriate and superior temporal cortex bilaterally. The neural mechanisms responsible for the two tasks (perceptual/motor) were not differentially modulated by space of presentation.     

Blood loss and operative duration using monopolar electrosurgery versus ultrasound scissors for surgical preparation during thoracoscopic ventral spondylodesis: results of a randomized,blinded, controlled trial

Purpose

Monopolar electrosurgery is the gold standard for surgical preparation in thoracoscopic spine procedures. However, use of ultrasound scissors could decrease blood loss, accelerate the preparation time and improve patient safety, while minimizing operative costs. This trial compares both preparation techniques for ventral thoracoscopic spondylodesis.

Methods

The study design is an open, prospective, randomized, and double-blinded two-armed clinical trial performed in two centres. Forty-one patients with vertebral body fractures from T10 to L2 were included. Primary endpoint: preparation time. Secondary endpoints: blood loss, organ injuries, duration of hospitalization.

Results

Primary and secondary endpoints did not differ significantly between groups (p level 0.05). Increased blood loss (150 ml or more) was eliminated with ultrasound scissors (p = 0.0014).

Conclusions

Primary and secondary endpoints did not differ significantly between the two preparation techniques. The use of either ultrasound scissors or electric scalpel offers safe and effective preparation for thoracoscopic spine surgery.     

Indoleamine 2,3-Dioxygenase Is Involved in Defense against Neospora caninum in Human and Bovine Cells

Neospora caninum is an apicomplexan parasite closely related to Toxoplasma gondii. In nature this parasite is found especially in dogs and cattle, but it may also infect other livestock. The growth of N. caninum, which is an obligate intracellular parasite, is controlled mainly by the cell-mediated immune response. During infection the cytokine gamma interferon (IFN-γ) plays a prominent role in regulating the growth of N. caninum in natural and experimental disease. The present study showed that induction of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) is responsible for the inhibition of parasite growth that is mediated by IFN-γ-activated bovine fibroblasts and endothelial cells. This antiparasite effect could be abrogated by addition of tryptophan, as well as by the IDO-specific inhibitor 1-l-methyltryptophan. In conclusion, our data show that human and bovine cells use the same effector mechanism to control the growth of N. caninum.Toxoplasma gondii, a protozoan belonging to the apicomplexan phylum, is one of the most successful parasites on earth. This parasite is capable of infecting nearly all warm-blooded animals, including humans. T. gondii can be transmitted via tissue cysts, raw meat, and environmental-resistant oocysts derived from cat feces and is able to spread transplacentally from mother to fetus. Furthermore, another special feature of this evolutionarily successful parasite is the fact that it usually causes asymptomatic infections and in most cases does not kill immunocompetent hosts. However, without sufficient therapy, reactivation of T. gondii in immunocompromised individuals frequently results in death of the host (31, 26, 18).In 1984 a T. gondii-like parasite was found in the cerebral tissue of dogs and described (5). This parasite was later detected in brain tissue from dogs which had clinical signs of neuromuscular disease and was named Neospora caninum (15). It took until 1998 to discover that dogs are not only intermediate hosts but also one of the definitive hosts of this parasite (29). In nature, dogs are frequently intermediate hosts of N. caninum, although canine neosporosis seems to be rare (2). N. caninum can also be isolated from cattle, and vertically transmitted N. caninum infection is considered an important cause of bovine abortion worldwide (17). In sheep N. caninum-associated abortion seems to be rare (16). This is in contrast to infections with T. gondii, which often cause abortion in sheep but seldom in cattle (14). Furthermore, so far, there is no evidence that N. caninum infection is zoonotic (16). It has been shown that under experimental conditions N. caninum is able to infect rhesus monkeys, indicating the zoonotic potential of this parasite. However, serologic studies with humans have shown that no or only small amounts of N. caninum-specific antibodies are detectable in some human sera, even sera from high-risk groups like farm workers (30, 16, 22). Despite the high levels of homology between T. gondii and N. caninum, many differences have also been detected. Both parasites can be transmitted via food, via oocysts in soil, and also transplacentally (23). Several species have been successfully infected experimentally with N. caninum, and in vitro N. caninum is capable of replicating in different types of cells derived from various animal species or humans.The variability in the susceptibility to natural T. gondii or N. caninum infection among various host species might be due to differences in the immune responses. Different antiparasite effector mechanisms might, at least in part, be involved in the evolutionary success of both parasites. In support of this, workers have obtained some data showing that experimental infection with attenuated or apathogenic N. caninum strains can induce immunity to this parasite in mice and cattle (3). Furthermore, a lot of data indicate that the cellular immune response is necessary to control infection with N. caninum. In addition, it was found that gamma interferon (IFN-γ), a product of activated T cells and natural killer (NK) cells, is one of the main cytokines conferring resistance to N. caninum (21). So far, the IFN-γ-induced effector mechanism that is active against N. caninum in cattle has not been defined.In this paper we provide evidence that induction of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO), which is the most prominent antiparasite effector mechanism active against T. gondii in human cells (28), is also effective for inhibiting N. caninum growth in tissue cells from humans and cattle.