The organization of frontostriatal brain wiring in non-affective early psychosis compared with healthy subjects using a novel diffusion imaging fiber cluster analysis.

BACKGROUND: Alterations in brain connectivity may underlie neuropsychiatric conditions such as schizophrenia. We here assessed the degree of convergence of frontostriatal fiber projections in 56 young adult healthy controls (HCs) and 108 matched Early Psychosis-Non-Affective patients (EP-NAs) using our novel fiber cluster analysis of whole brain diffusion magnetic resonance imaging tractography. METHODS: Using whole brain tractography and our fiber clustering methodology on harmonized diffusion magnetic resonance imaging data from the Human Connectome Project for Early Psychosis we identified 17 white matter fiber clusters that connect frontal cortex (FCtx) and caudate (Cd) per hemisphere in each group. To quantify the degree of convergence and, hence, topographical relationship of these fiber clusters, we measured the inter-cluster mean distances between the endpoints of the fiber clusters at the level of the FCtx and of the Cd, respectively. RESULTS: We found (1) in both groups, bilaterally, a non-linear relationship, yielding convex curves, between FCtx and Cd distances for FCtx-Cd connecting fiber clusters, driven by a cluster projecting from inferior frontal gyrus; however, in the right hemisphere, the convex curve was more flattened in EP-NAs; (2) that cluster pairs in the right (p = 0.03), but not left (p = 0.13), hemisphere were significantly more convergent in HCs vs EP-NAs; (3) in both groups, bilaterally, similar clusters projected significantly convergently to the Cd; and, (4) a significant group by fiber cluster pair interaction for 2 right hemisphere fiber clusters (numbers 5, 11; p = .00023; p = .00023) originating in selective PFC subregions. CONCLUSIONS: In both groups, we found the FCtx-Cd wiring pattern deviated from a strictly topographic relationship and that similar clusters projected significantly more convergently to the Cd. Interestingly, we also found a significantly more convergent pattern of connectivity in HCs in the right hemisphere and that 2 clusters from PFC subregions in the right hemisphere significantly differed in their pattern of connectivity between groups.

Circulating low-density lipoprotein ceramide concentrations increase in Holstein dairy cows transitioning from gestation to lactation.

Low-density lipoprotein (LDL) ceramide causes insulin resistance in obese diabetic nonruminants. Because previous work suggests that liver-derived ceramide may impair insulin action in postpartum cows, our objectives were to characterize peripartal changes in lipoprotein ceramides. We further studied the effects of prepartum adiposity on lipoprotein ceramide levels. Twenty-eight pregnant Holstein cows (parity = 3.65 ± 1.62) with lean (body condition score, BCS = 2.97 ± 0.16; body weight, BW = 630 ± 55.2 kg; n = 15) or overweight (BCS = 3.93 ± 0.27; BW = 766 ± 46.1 kg; n = 13) body condition 28 d before expected parturition were evaluated. Sampling occurred on d -20.5 ± 1.74, -13.8 ± 1.71, -7.84 ± 4.07, -6.71 ± 1.00, -3.92 ± 0.64, and -1.28 ± 0.61 (before parturition); daily until d 8 postpartum; and on d 10, 12, 14, 21, and 28. Adipose tissue and liver were biopsied on d -7.84 ± 4.07 and 10. Postpartum insulin sensitivity was assessed using the hyperinsulinemic-euglycemic clamp. Lipoprotein fractions were isolated using liquid chromatography. Sphingolipids were quantified using mass spectrometry. Data were analyzed using a mixed model with repeated measures. Overweight cows had a higher BCS and BW at enrollment relative to lean cows, but BCS and BW were similar postpartum. Overweight cows lost more body condition (0.97 ± 0.36 vs. 0.55 ± 0.16 BCS units) and BW (291 ± 67.3 vs. 202 ± 54.5 kg) during transition relative to lean cows. Adipocyte volume and counts declined from prepartum to postpartum (50.4 and 13.7%, respectively), and adipocyte volume was greater (48.2%) in overweight cows prepartum relative to lean cows. Although DMI was comparable between BCS groups, milk yield tended to be greater in overweight cows. Plasma free fatty acid and ß-hydroxybutyrate and liver lipid levels were 40, 16, and 37% greater, respectively, in overweight cows compared with lean cows. Glucose infusion rate during the hyperinsulinemic-euglycemic clamp tended to be lower in overweight cows. Ceramide levels within triacylglycerol-rich lipoprotein fractions declined postpartum, whereas LDL ceramide increased postpartum. Overweight cows had lower triacylglycerol-rich lipoprotein C16:0-ceramide levels relative to lean cows. Prepartum LDL C24:0-ceramide levels were greater in overweight cows relative to lean cows. Independent of prepartum adiposity, we concluded that serum LDL ceramide levels are elevated in early-lactation cows experiencing adipose tissue free fatty acid mobilization and hepatic steatosis.

Inter-site and inter-scanner diffusion MRI data harmonization.

We propose a novel method to harmonize diffusion MRI data acquired from multiple sites and scanners, which is imperative for joint analysis of the data to significantly increase sample size and statistical power of neuroimaging studies. Our method incorporates the following main novelties: i) we take into account the scanner-dependent spatial variability of the diffusion signal in different parts of the brain; ii) our method is independent of compartmental modeling of diffusion (e.g., tensor, and intra/extra cellular compartments) and the acquired signal itself is corrected for scanner related differences; and iii) inter-subject variability as measured by the coefficient of variation is maintained at each site. We represent the signal in a basis of spherical harmonics and compute several rotation invariant spherical harmonic features to estimate a region and tissue specific linear mapping between the signal from different sites (and scanners). We validate our method on diffusion data acquired from seven different sites (including two GE, three Philips, and two Siemens scanners) on a group of age-matched healthy subjects. Since the extracted rotation invariant spherical harmonic features depend on the accuracy of the brain parcellation provided by Freesurfer, we propose a feature based refinement of the original parcellation such that it better characterizes the anatomy and provides robust linear mappings to harmonize the dMRI data. We demonstrate the efficacy of our method by statistically comparing diffusion measures such as fractional anisotropy, mean diffusivity and generalized fractional anisotropy across multiple sites before and after data harmonization. We also show results using tract-based spatial statistics before and after harmonization for independent validation of the proposed methodology. Our experimental results demonstrate that, for nearly identical acquisition protocol across sites, scanner-specific differences can be accurately removed using the proposed method.

Molecular intimacy between proteins specifying plant-pathogen recognition.

Disease resistance in plants is commonly specified by genetically paired plant resistance (R) and pathogen avirulence (Avr) proteins. Recent molecular analyses of several R-Avr protein interactions provide compelling evidence for a receptor-ligand mechanism in which specific binding of the Avr elicitor by its matching R protein leads to activation of the plant defence response. Direct R-Avr protein recognition precedes the function of an expanding battery of plant resistance signalling components.

Microbiota of plaque microcosm biofilms: effect of three times daily sucrose pulses in different simulated oral environments.

AIM: To explore the Ecological Plaque Hypothesis for dental caries. To test modification of the microbiota of dental plaque microcosm biofilms by sucrose pulsing during growth in two different simulated oral fluids, and with a urea-induced plaque pH elevation. METHODS: Plaque microcosm biofilms were cultured in an 'artificial mouth' with and without 6-min 5% w/v sucrose pulses every 8 h in an environment of continuously supplied saliva-like defined medium with mucin (DMM), or basal medium mucin (BMM, a high-peptone-yeast extract oral fluid analogue), and also in DMM + 10 mmol/l urea, with sucrose pulsing. Forty plaque species were quantified by checkerboard DNA:DNA hybridization analysis. RESULTS: Sucrose pulsing extended rapid plaque growth in DMM and BMM, inducing major microbiota changes in DMM but not in BMM. In DMM, some streptococci and lactobacilli were unaffected while others implicated in caries, together with Candida albicans and Capnocytophaga gingivalis, increased. Aerobic, microaerophilic and major anaerobic species decreased. Elevation of the pH(max) from 6.4 to 7.0 had almost no effect on the microbiota. BMM plaques were distinct from DMM plaques with particularly low levels of Candida albicans and Actinomyces. CONCLUSIONS: Modest sucrose exposure in a saliva-like environment causes profound changes in the developmental self-organization of plaque microcosms, supporting the Ecological Plaque Hypothesis. Nevertheless, there is significant stability in microbial composition with varying pH near neutrality. Increases in levels of specific bacteria in response to sucrose could be characteristic of organisms particularly important in caries.

The prognostic significance of neuroendocrine markers and carcinoembryonic antigen in patients with resected stage I and II non-small cell lung cancer.

Non-small cell lung cancer with neuroendocrine differentiation may represent a subset of patients with a more aggressive (like small cell lung cancer) or less aggressive (like carcinoid) biological behavior. To investigate their prognostic significance, immunohistochemical stains for 4 neuroendocrine markers (neuron-specific enolase, chromogranin A, Leu-7, and synaptophysin) and carcinoembryonic antigen (CEA) were studied in 260 patients with surgically resected stage I and II non-small cell lung cancer. The following percentages of cases were positive for each marker: neuron-specific enolase, 70.0%; chromogranin A, 14.2%; Leu-7, 7.7%; synaptophysin, 11.2%; and CEA, 68.5%. Sixty-one (23.5%) were positive for > or = 2 neuroendocrine markers. When compared to adenocarcinoma, squamous cell carcinoma displayed lower positivity for CEA and > or = 2 neuroendocrine markers. There was no significant difference in stage, site of relapse (distant versus local), disease-free, or overall survival for each marker individually or for those with > or = 2 neuroendocrine markers. Multivariate analysis showed that higher nodal stage (N1 versus N0), tumor stage (T2 versus T1), older age, and the presence of mucin predicted for poorer overall survival. Neuroendocrine markers and CEA were not of prognostic significance in this group of patients with resected stage I and II non-small cell lung cancer.

Simultaneous saccharification and fermentation of steam exploded duckweed: Improvement of the ethanol yield by increasing yeast titre.

This study investigated the conversion of Lemna minor biomass to bioethanol. The biomass was pre-treated by steam explosion (SE, 210°C, 10 min) and then subjected to simultaneous saccharification and fermentation (SSF) using Cellic® CTec 2 (20 U or 0.87 FPU g(-1) substrate) cellulase plus ß-glucosidase (2 U g(-1) substrate) and a yeast inoculum of 10% (v/v or 8.0×10(7) cells mL(-1)). At a substrate concentration of 1% (w/v) an ethanol yield of 80% (w/w, theoretical) was achieved. However at a substrate concentration of 20% (w/v), the ethanol yield was lowered to 18.8% (w/w, theoretical). Yields were considerably improved by increasing the yeast titre in the inoculum or preconditioning the yeast on steam exploded liquor. These approaches enhanced the ethanol yield up to 70% (w/w, theoretical) at a substrate concentration of 20% (w/v) by metabolising fermentation inhibitors.

Cloning and characterisation of telomeric DNA from Cladosporium fulvum.

The molecular cloning of DNA from the telomere of one chromosome of Cladosporium fulvum, a fungal pathogen of tomato, is described. The telomeric DNA exhibits tandem repeats of the sequence TTAGGG running 5' to 3' toward the chromosome end. At least 16 tracts of TTAGGG repeats are present in the C. fulvum genome. All such tracts are telomeric, and all chromosome-sized DNAs separated by pulsed-field gel electrophoresis exhibit the repeats. It is probable that tracts of these repeats are present at all chromosome termini. The cloned telomeric DNA exhibits 19 copies of the TTAGGG hexanucleotide motif, and evidence is presented indicating that all tracts of TTAGGG repeats are quite short. Telomere-linked restriction-fragment length polymorphisms between races of C. fulvum have been detected, and groupings based on these polymorphisms are consistent with those determined previously. Sub-telomeric DNA, centromere proximal to the cloned telomeric DNA, contains sequences reiterated many times in the genome; some of these repeats are at non-terminal locations. Partial sequence analysis indicates an absence of homology with the sub-telomeric DNA of other organisms.

Distribution of modulatory inputs to the stomatogastric ganglion of the crab, Cancer borealis.

The pyloric and gastric mill neural networks in the crustacean stomatogastric ganglion receive modulatory inputs from more anteriorly located ganglia via the stomatogastric nerve. In this study we employed biocytin backfilling and immunostaining, as well as electron microscopy, to determine the origin of these inputs in the crab, Cancer borealis. Fiber counts from electron micrographs of sections through the stomatogastric nerve showed that this nerve contains 55-60 medium to large diameter fibers (1-13 microns). These fibers were individually wrapped by several layers of membrane, presumably glial in origin. There was also a single cluster of jointly wrapped, small diameter (< 1 micron) fibers that may originate from peripheral sensory somata. Biocytin backfills revealed that approximately two thirds of the individually wrapped fibers in this nerve originate from somata in the other three ganglia of the stomatogastric nervous system, including the paired commissural ganglia and the single oesophageal ganglion. There were approximately 20 biocytin-labeled somata in each commissural ganglion and 3 somata in the oesophageal ganglion. An additional ten somata were localized to the stomatogastric ganglion itself. This accounts for nearly all of the medium to large diameter fibers in the stomatogastric nerve. We used double-labeling with backfills and immunocytochemistry to determine that there are two proctolin-immunoreactive neurons and four FMRFamide-like immunoreactive neurons among the biocytin-labeled neurons in each commissural ganglion. Both peptides modulate neural network activity in the stomatogastric ganglion.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperalimentation as cause of markedly worsened metabolic control in a patient with autoantibodies to the insulin receptor.

Patients with type B insulin resistance and acanthosis nigricans have autoantibodies to their insulin receptors and usually have signs and symptoms of other autoimmune diseases. The first case demonstrating that hyperalimentation markedly disturbs blood glucose control in type B insulin-resistant patients is described. Neither prednisone, insulin (up to 240 units per hour), nor tolbutamide appeared to help this patient's metabolic control. After the addition of cyclophosphamide for one week, the anti-insulin receptor autoantibody titer dropped from greater than 1:1,000 to 1:1. Six months later, the patient had a complete remission, which is rare, with only three other reported remissions in these patients with type B insulin resistance.

Use of unopposed estrogen in women with uteri: prevalence, clinical implications, and economic consequence.

OBJECTIVE: Hormone replacement therapy with estrogen/progestin is the treatment of choice for relieving postmenopausal vasomotor symptoms and preventing urogenital atrophy and osteoporosis in women with intact uteri. However, despite the known increased incidence of endometrial hyperplasia when unopposed estrogen is used in such women, this progestin regimen has not been universally adopted. DESIGN: This study was conducted in a managed care organization to determine the extent of the use of unopposed estrogen in women with intact uteri. Pharmacy claims data for all women 55 years or older with claims for estrogen only from September 1, 1996, to December 31, 1996, were reviewed. A total of 5,209 records were identified, from which 480 were randomly selected. A survey of the members' physicians was then carried out to determine hysterectomy status and was confirmed by chart audit. RESULTS: Thirty-three (11%) of the members identified had not undergone hysterectomy. Follow-up physician contact revealed that five women did not have a uterus. Use of estrogen without opposing progestin was documented in a substantial percentage of files reviewed. It is of concern that with the documentation of the risks of endometrial hyperplasia and carcinoma in the intact uterus, unopposed therapy still occurs. In addition to the clinical costs, there are economic consequences to this practice. An economic model of unopposed estrogen use was created. A management cost of $1,504 for 3 years was estimated. CONCLUSIONS: Further educational efforts are needed to ensure the use of opposed estrogen in the woman with an intact uterus.

Autoradiography of [3H]alpha,beta-methylene-ATP binding sites in medulla oblongata and spinal cord of the rat.

Excitatory purinoceptors of P2x-type have long been known to exist on smooth muscle cells, but recently it has been shown that they are also involved in synaptic transmission in the CNS. We have used a P2x-specific agonist, alpha,beta-methylene-ATP, as a 3H-labelled radioligand, to study the distribution and characteristics of P2x receptor-binding sites in the spinal cord and medulla oblongata. Using auto-radiographic techniques, [3H]alpha,beta-methylene-ATP binding was found throughout the grey matter of the spinal cord with small areas of above-average density of binding sites in the marginal zone and substantia gelatinosa at all spinal levels and in the central grey matter of the thoracic spinal cord. In the medulla, [3H]alpha,beta-methylene-ATP binding was found to be strong in all cranial nerve nuclei, particularly those known to receive primary sensory fibres. We have found that the binding of [3H]alpha,beta-methylene-ATP in the spinal cord and medulla was inhibited by a broad-spectrum P2-receptor antagonist suramin (IC50 approximately 27 microM). This is in accordance with the data obtained previously in the forebrain and cerebellum. There was, however, no inhibition of [3H]alpha,beta-methylene-ATP binding by another close analogue of alpha,beta-methylene-ATP and P2x ligand beta,gamma-methylene-ATP (10 microM). The latter result is discussed in terms of possible involvement of Ca2+ in the binding of [3H]alpha,beta-methylene-ATP to P2x receptors in the CNS.

Cholecystectomy in cardiothoracic organ transplant recipients.

OBJECTIVES: To assess the risks associated with cholelithiasis and cholecystectomy in cardiothoracic organ transplant recipients at this hospital and to identify any differences with potential causal significance between the group with known gallstones and the transplant recipient group as a whole. DESIGN: Medical records survey. SETTING: Tertiary care university hospital. PATIENTS: Six hundred forty-five patients had cardiothoracic organ transplantation at this hospital between February 1, 1984, and May 31, 1996. Gallstones were detected in 37 (5.7%) of these patients and 32 patients underwent cholecystectomy, of which 29 operations were performed primarily for symptomatic gallstone disease. All cholecystectomies were performed after transplantation. MAIN OUTCOME MEASURES: Mortality, morbidity, postoperative biliary disease. RESULTS: Patients with gallstones were significantly older than the transplant patient group as a whole (Student t test, P=.001); they were more likely to be female (chi2 test, P=.05); and they had a higher body mass index (t test, P=.001). There were no significant differences in the maximum serum bilirubin level during the transplantation admission, incidence of diabetes mellitus, cholestyramine use, or cyclosporine dosage during the first 12 months after transplantation. Cholecystectomy was performed after a median 5-month symptomatic period, mostly by the minilaparotomy method. Forty-five percent of cholecystectomies were urgent or semi-urgent. One patient died of lung infection on the second postoperative day. The median postoperative stay was 3 days. At a median 33 months' follow-up, 4 patients have had further biliary problems (2 patients with common bile duct stones, 1 patient with intrahepatic stones, and 1 patient with biliary dyskinesia). Four other patients with asymptomatic gallstones who did not receive cholecystectomy have remained asymptomatic for between 15 and 67 months. CONCLUSIONS: Cholecystectomy by the minilaparotomy or laparoscopic methods, with routine operative cholangiography, is the preferred treatment for symptomatic gallstones in cardiothoracic organ transplant recipients. Although the optimum management of asymptomatic gallstones in these patients remains unclear, our favorable experience with a policy of reserving cholecystectomy for symptomatic cases seems noteworthy.

Splenectomy for HIV-related immune thrombocytopenia: comparison with results of splenectomy for non-HIV immune thrombocytopenic purpura.

OBJECTIVE: To determine the effectiveness and safety of splenectomy for patients with human immunodeficiency virus (HIV)-related immune thrombocytopenia, using the results of splenectomy for patients with non-HIV immune thrombocytopenic purpura as a control group for comparison. DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PATIENTS: Fourteen patients who underwent splenectomy for symptomatic, medically refractory HIV-related immune thrombocytopenia at this hospital from 1988 to 1997. During the same period, 20 patients had splenectomy for treatment of non-HIV immune thrombocytopenic purpura. INTERVENTION: Splenectomy. MAIN OUTCOME MEASURES: Platelet response, need for postsplenectomy medical therapy, progression of HIV disease, and complications. RESULTS: All patients with HIV-related thrombocytopenia had a complete early platelet response to splenectomy, with an elevation of the platelet count to greater than 100X10(9)/L. After a median follow-up of 26.5 months, all but 1 patient had a sustained complete remission with no need for medical therapy for thrombocytopenia. Splenectomy was more effective in the HIV-related thrombocytopenia group than in the non-HIV immune thrombocytopenic purpura group, with significantly higher platelet counts at 1 week and 1 month after splenectomy in the HIV group (t test, P=.02 and P=.009, respectively). There were significantly fewer patients needing medical therapy for thrombocytopenia after splenectomy in the HIV group (chi2 test, P=.02). There were no remarkable short- or long-term complications in the patients with HIV infection, including no overwhelming postsplenectomy infections. Three patients have died, and 2 patients have developed AIDS since operation. CONCLUSIONS: Splenectomy is effective treatment for patients with symptomatic HIV-related thrombocytopenia that is resistant to medical therapy. The effectiveness of this treatment suggests that the predominant mechanism of thrombocytopenia in HIV-infected patients is increased destruction of platelets because of platelet-associated immunoproteins.

Incidence of deep vein thrombosis after laparoscopic vs minilaparotomy cholecystectomy.

OBJECTIVES: To determine the frequency of deep vein thrombosis (DVT) associated with minimally invasive cholecystectomy and to determine, using minilaparotomy cholecystectomy as a control operation, the influence of the laparoscopic pneumoperitoneum on DVT formation. DESIGN: Prospective nonrandomized control trial. SETTING: Tertiary care university hospital. PATIENTS: One hundred consecutive patients intended to undergo either laparoscopic cholecystectomy (59 patients) or minilaparotomy cholecystectomy (41 patients) with either of 2 surgeons were prospectively enrolled between April 1996 and April 1997. The minilaparotomy cholecystectomy group served as controls to isolate the effect of the pneumoperitoneum. Patient details, operative details, and any thromboembolic or bleeding complications were recorded. The same thromboprophylaxis regimen was prescribed for each group; namely, preoperative and postoperative subcutaneous low-molecular-weight heparin (LMWH), graduated compression stockings, and intraoperative intermittent calf compression. INTERVENTION: Minimally invasive cholecystectomy. MAIN OUTCOME MEASURE: Frequency of DVT. Bilateral lower limb venous color duplex scanning was used to detect DVT. Scans were performed on 3 occasions: (1) preoperatively on admission to hospital, (2) on the first postoperative day, and (3) between 2 and 4 weeks postoperatively. RESULTS: Three patients in the laparoscopic group and 2 patients in the minilaparotomy group underwent conversion to conventional open cholecystectomy. There were no significant differences between patients in the 2 groups for age, sex, body mass index, preoperative white blood cell count, platelet count, prothrombin time, or activated partial thromboplastin time. There were no significant differences between the 2 groups for elective vs emergency operations, public hospital vs private hospital admissions, or consultant vs resident surgeon. Macroscopic gallbladder pathology grades for both groups were not significantly different, and there was no significant difference in the duration of postoperative hospital stay. Operative cholangiography was performed in a significantly larger proportion of laparoscopic cases (86% vs 66% in the minilaparotomy group; chi(2) test, P=.002), and the duration of anesthesia was significantly longer for the laparoscopic operation (118 minutes vs 98 minutes; t test, P=.05). Ninety-seven patients received preoperative LMWH and all patients received graduated compression stockings, intraoperative intermittent calf compression, and postoperative LMWH. Two of the 100 patients had postoperative DVT, 1 after laparoscopic cholecystectomy and 1 after minilaparotomy cholecystectomy. Both DVTs were detected by duplex examination on the first postoperative day. The DVT found after laparoscopic cholecystectomy was in 1 of the 3 patients who did not receive preoperative LMWH. There were no DVTs in any of the 40 patients who had an additional duplex scan between 2 and 4 weeks after operation. CONCLUSIONS: Despite the theoretical risk of thromboembolic disease due to use of the laparoscopic pneumoperitoneum, the frequency of DVT after either laparoscopic cholecystectomy or minilaparotomy cholecystectomy is low if adequate thromboprophylaxis is provided.

Bacteremia and sternal infection after coronary artery bypass grafting.

Sternal wound infection remains a source of substantial morbidity and mortality after coronary artery bypass grafting. We noted an association between bacteremias and sternal wound complications in these patients. A review of 835 consecutive coronary bypass patients showed a 3.2% incidence of bacteremia and a 1.9% incidence of deep and superficial sternal wound infection. The sternal wound was the most common source of bacteremia, accounting for 59% of the infections. Coagulase-negative Staphylococcus was responsible for one half of the sternal wound infections. Often, a positive blood culture was the first manifestation of wound infection, occurring before local signs were manifest. We recommend multiple blood cultures in postoperative coronary bypass patients with pronounced fever. If no source of infection can be identified, sternal wound aspirate may be revealing. Appropriate early wound management can then be carried out, maximizing chances for good recovery.

The cardiovascular effects of angiotensin-(1-7) in the rostral and caudal ventrolateral medulla of the rabbit.

Previous studies in the rat have indicated that the heptapeptide angiotensin-(1-7) has an excitatory action on pressor neurons in the rostral ventrolateral medulla that is equipotent to that evoked by angiotensin II, but which is mediated by separate receptors. In this study we have compared the cardiovascular effects and mechanisms of action of angiotensin-(1-7) with angiotensin II in the rostral and caudal ventrolateral medulla of the rabbit, a species which, unlike the rat, contains a high density of angiotensin receptors, similar to that observed in humans. Microinjections of angiotensin-(1-7) into the rostral and caudal ventrolateral medulla evoked dose-dependent increases and decreases, respectively, in arterial pressure and renal sympathetic nerve activity, but in comparison to angiotensin II much higher doses (approximately 50-fold higher) were required to produce cardiovascular response of similar magnitude. The cardiovascular effects of angiotensin-(1-7) were blocked by prior injection of the selective antagonist [D-Ala(7)]-Ang-(1-7) but were also blocked by the selective AT(1) receptor antagonist losartan. The results demonstrate that in the rabbit angiotensin-(1-7) can excite pressor and depressor neurons in the ventrolateral medulla, but indicate that these effects are mediated by AT(1) receptors. The much lower potency of angiotensin-(1-7) as compared to angiotensin II may be explained as a consequence of it having a much lower affinity to AT(1) receptors. Thus, in contrast to the rat, the results do not indicate that angiotensin-(1-7) has a biologically significant action in the ventrolateral medulla of the rabbit.

Thought disorder, perceptual aberrations, and schizotypy.

Empirical links between schizophrenia and schizotypic psychopathology were examined. The Perceptual Aberration Scale (PerAb; L. J. Chapman, J. O. Chapman, & M. L. Raulin, 1978) was used to identify putative schizotypic individuals and a contrast group of nonschizotypic controls. The Thought Disorder Index (TDI; M. J. Coleman et al., 1993) was used to quantify and classify thought disorder in these individuals. High PerAb participants, selected for having an increased number of self-reported perceptual and body image aberrations, showed an elevation in the amount and frequency of thought disorder as well as an increased number of idiosyncratic verbalizations. This supports the hypothesis that psychometrically identified schizotypic individuals display thought disorder similar to that shown by schizophrenic patients and some of their 1st-degree relatives, suggesting that there is a relation between schizotypic psychopathology, as tapped by the PerAb scale, and clinical schizophrenia.

Antral patch esophagoplasty. A new procedure for acid-peptic esophageal stricture.

Antral patch esophagoplasty is a new procedure for intractable fibrous stricture of the esophagus secondary to acid-peptic reflux. A full-thickness patch of gastric antrum, supplied by a pedicle based on the left gastroepiploic vessels, is inserted, mucosal surface to lumen, into the opened stricture. A fundoplication is done below the esophagoplasty to prevent reflux. The functional results were excellent in five of six patients. The procedure may have application also in other types of benign esophageal stricture.

Gastric patch esophagoplasty: an experimental study.

To determine whether the use of pedicled full-thickness gastric patches would be feasible and safe in esophageal reconstruction, studies were undertaken in eleven dogs. The results demonstrate that patches containing parietal cell mucosa are likely to produce localized adjacent esophagitis. Patches containing antral mucosa do not produce esophagitis and are not associated with a subsequent increase in circulating serum gastrin levels.