Comparison of double-bag and Y-set disconnect systems in continuous ambulatory peritoneal dialysis: a randomized prospective multicenter study.

We performed a multicenter, single-blinded, prospective randomized study on the use of a double-bag disconnect system (B) versus a Y-set disconnect system (Y). The peritonitis rate, exit site infection, clinical outcome, and patients' acceptance to the procedure were assessed. A total of 120 new end-stage renal failure patients of three regional hospitals were randomized: 60 each to the B and the Y systems. The results of 60 patients on the B system and 51 on the Y system were analyzable. They were followed up for a median of 16 months. Peritonitis rates for the B and the Y systems were 33.5 and 29.4 patient-months per episode, respectively. Exit site infection rates for the B and Y systems were 17.4 and 16.0 patient-months per episode, respectively. Four catheters were removed in each group. Patients on the B system were hospitalized for 2.1 days per patient per year related to peritonitis and exit site infection, and those on the Y system were hospitalized for 1.2 days. There was no significant difference between the B and Y systems in the incidences of peritonitis (all causes and those due to coagulase-negative staphylococci), exit site infection, and in hospitalization days. However, there was a higher percentage of gram-positive infections in the Y system (52%) than in the B system (32%) and a lower percentage of gram-negative infections in the Y system (16%) than in the B system (32%). Patients on the B system had a better acceptance of the procedure than patients on the Y system, as assessed by a six-item, 10-point questionnaire (total score, 43.1 +/- 10.2 v 37.6 +/- 9.4; P < 0.005 at 1 month; 44.6 +/- 9.1 v 39.8 +/- 8.6; P < 0.01 at 6 months). From this study, it is concluded that the B and Y systems are similar in the incidences of peritonitis and exit site infection, although the B system is better accepted by patients. This is probably the first multicenter randomized study comparing the double-bag and Y-set disconnect system using only new patients who had never used other systems of continuous ambulatory peritoneal dialysis.     

Evaluation of [11C]GB67, a novel radioligand for imaging myocardial α1-adrenoceptors with positron emission tomography

Dysfunction of the sympathetic nervous system underlies a number of myocardial disorders. Positron emission tomography (PET) offers a way of assessing receptor function non-invasively in humans, but there are no PET radioligands for assessing myocardial α-adrenoceptors. GB67, a structural and pharmacological analogue of the α₁-adrenoceptor antagonist prazosin, was labelled with positron-emitting carbon-11 (t _1/2=20.4 min) by ¹¹C-methylation of N-desmethylamido-GB67 (GB99). [¹¹C]GB67 was injected intravenously into conscious rats. Serial arterial blood samples were taken. Rats were killed and tissues removed to determine radioactivity. The percentages of unchanged [¹¹C]GB67 and its radioactive metabolites in plasma and tissues were assessed by HPLC. Plasma clearance of radioactivity was rapid. Myocardial uptake was maximal at 1–2 min and decreased slowly during 60 min. Predosing with adrenoceptor antagonists demonstrated selectivity for myocardial α₁-adrenoceptors. GB67 and prazosin blocked uptake of radioactivity; the non-selective antagonist, phentolamine, partially blocked uptake; the α₂-adrenoceptor antagonist, RX 821002, only blocked uptake at high dose and the β-adrenoceptor antagonist, CGP 12177, had no effect. Additionally, injection of prazosin at 20 min after radioligand displaced radioactivity. In vivo competition curves obtained by injecting [¹¹C]GB67 with varying amounts of either unlabelled GB67 or its precursor GB99 were fitted to a competitive binding model to provide estimates of the maximum number of binding sites (B _max) and half saturation doses (K) for myocardium. Assuming a tissue protein content of 10%, the values of B _max [∼13 pmol·(g tissue)^–1] were similar to those [50–170 fmol·(mg protein)^–1] reported for myocardial α₁-adrenoceptors assessed in vitro. Both GB67 and its precursor GB99 had high affinity for α₁-adrenoceptors [K _GB67=1.5 nmol·(kg body weight)^–1, K _GB99=4.8 nmol· (kg body weight)^–1]. HPLC demonstrated four radioactive metabolites in plasma. [¹¹C]GB67 was 80% of the radioactivity at 5 min and 50% at 45 min. No radioactive metabolites were detected in myocardium up to 60 min after injection. [¹¹C]GB67 was assessed in two male human volunteers. PET demonstrated high myocardial uptake. The profile of radioactive metabolites in plasma was comparable to that in the rat, although metabolism was slower in humans. Thus, [¹¹C]GB67 is a promising radioligand for assessing α₁-adrenoceptors in human myocardium with PET. Received 7 May and in revised form 9 August 1999     

An evaluation of preoperative ibuprofen for treatment of pain associated with orthodontic separator placement

Patients undergoing orthodontic treatment can experience significant levels of pain. This study assessed the effectiveness of preoperative ibuprofen in reducing the incidence and the severity of pain after orthodontic separator placement. Sixty-three adolescent patients (mean age, 13 years) were included in this randomized, double-blind, placebo-controlled, prospective study. Patients were randomly assigned to 1 of 3 experimental conditions: (1) 400 mg of ibuprofen taken orally 1 hour before separator placement and a lactose placebo taken orally immediately after the appointment, (2) a lactose placebo taken orally 1 hour before separator placement and 400 mg of ibuprofen taken orally immediately after the appointment, or (3) a lactose placebo taken orally 1 hour before separator placement and again immediately after the appointment. The patient's level of discomfort was assessed with a visual analog scale at 2, 6, and 24 hours, as well as at 2, 3, and 7 days after placement of the orthodontic separators. An analysis of variance and Duncan's multiple range test revealed that 2 hours after their orthodontic appointment the patients who had taken ibuprofen 1 hour before separator placement had significantly less pain with chewing than did the patients who received either ibuprofen postoperatively or a placebo. Additional measures suggest a trend for less pain for this group of patients. These results support the use of pretreatment ibuprofen for patients requiring analgesics for orthodontic discomfort. Future study of the use of preemptive analgesics in orthodontics is warranted.     

Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET: II. Normal values and gray matter blood flow response to visual activation.

One of the most limiting factors for the accurate quantification of physiologic parameters with positron emission tomography (PET) is the partial volume effect (PVE). To assess the magnitude of this contribution to the measurement of regional cerebral blood flow (rCBF), the authors have formulated four kinetic models each including a parameter defining the perfusable tissue fraction (PTF). The four kinetic models used were 2 one-tissue compartment models with (Model A) and without (Model B) a vascular term and 2 two-tissue compartment models with fixed (Model C) or variable (Model D) white matter flow. Furthermore, rCBF based on the autoradiographic method was measured. The goals of the study were to determine the following in normal humans: (1) the optimal model, (2) the optimal length of fit, (3) the model parameters and their reproducibility, and (4) the effects of data acquisition (2D or 3D). Furthermore, the authors wanted to measure the activation response in the occipital gray matter compartment, and in doing so test the stability of the PTF, during perturbations of rCBF induced by visual stimulation. Eight dynamic PET scans were acquired per subject (n = 8), each for a duration of 6 minutes after IV bolus injection of H2(15)O. Four of these scans were performed using 2D and four using 3D acquisition. Visual stimulation was presented in four scans, and four scans were during rest. Model C was found optimal based on Akaike's Information Criteria (AIC) and had the smallest coefficient of variance after a 6-minute length of fit. Using this model the average PVE corrected rCBF during rest in gray matter was 1.07 mL x min(-1) x g(-1) (0.11 SD), with an average coefficient of variance of 6%. Acquisition mode did not affect the estimated parameters, with the exception of a significant increase in the white matter rCBF using the autoradiographic method (2D: 0.17 mL x min(-1) x g(-1) (0.02 SD); 3D: 0.21 mL x min(-1) x g(-1) (0.02 SD)). At a 6-minute fit the average gray matter CBF using Models C and D were increased by 100% to 150% compared with Models A and B and the autoradiographic method. There were no significant changes in the perfusable tissue fraction by the activation induced rCBF increases. The largest activation response was found using Model C (median = 39.1%). The current study clearly demonstrates the importance of PVE correction in the quantitation of rCBF in normal humans. The potential use of this method is to cost-effectively deliver PVE corrected measures of rCBF and tissue volumes without reference to imaging modalities other than PET.     

A Review of the Emerging White Chick Hatchery Disease

White chick hatchery disease is an emerging disease of broiler chicks with which the virus, chicken astrovirus, has been associated. Adult birds typically show no obvious clinical signs of infection, although some broiler breeder flocks have experienced slight egg drops. Substantial decreases in hatching are experienced over a two-week period, with an increase in mid-to-late embryo deaths, chicks too weak to hatch and pale, runted chicks with high mortality. Chicken astrovirus is an enteric virus, and strains are typically transmitted horizontally within flocks via the faecal–oral route; however, dead-in-shell embryos and weak, pale hatchlings indicate vertical transmission of the strains associated with white chick hatchery disease. Hatch levels are typically restored after two weeks when seroconversion of the hens to chicken astrovirus has occurred. Currently, there are no commercial vaccines available for the virus; therefore, the only means of protection is by good levels of biosecurity. This review aims to outline the current understanding regarding white chick hatchery disease in broiler chick flocks suffering from severe early mortality and increased embryo death in countries worldwide.     

Guidelines for buccal smear collection in breast-fed infants

Buccal smear analysis is a noninvasive, fast, and relatively inexpensive diagnostic method. It is used commonly where rapid gender identification is necessary or, more recently, for detection of aneusomy, microdeletion syndromes, and a variety of polymerase chain reaction–based molecular genetic tests. Previously we have shown that maternal cells can contaminate buccal smears taken from breast-fed infants, resulting in difficulty with test interpretation. The aim of this study was to determine optimal timing and technique for buccal smear collection in breast-fed infants in order to avoid diagnostic errors. We analyzed prospectively 50 breast-fed male infants for presence of cells with XX signal pattern from buccal mucosa scrapings at different times after breast feeding. The efficiency of mucosal cleaning on elimination of maternal cells was evaluated by comparing the proportion of XX cells before and after wiping of buccal mucosa with a cotton swab. Maternal cells were present in 23 of 48 (47.9%) samples collected within 5 min of feeding. The proportion of XX signal pattern was significantly (P = 0.001) reduced in samples collected at 30 min (8/48, P = 0.001) and ≥60 min (2/29, P = 0.0002) after feeding. Mucosal cleaning prior to smear collection significantly decreased the number of XX positive samples from 23 of 48 to 10 of 48 (P = 0.002). Buccal smears should not be obtained in nursing neonates until at least 60 min after breast feeding. In addition, prior to sample collection, buccal mucosa should be cleaned thoroughly with a cotton swab applicator. The same guidelines are applicable to older nursing infants. Am. J. Med. Genet. 84:357–360, 1999. © 1999 Wiley-Liss, Inc.     

Hepatocyte growth factor promotes cancer cell migration and angiogenic factors expression: a prognostic marker of human esophageal squamous cell carcinomas.

PURPOSE: Hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, c-Met, play important roles in tumor development and progression. In this study, we measured the serum HGF levels in patients with esophageal squamous cell carcinoma (ESCC) to evaluate its relationships with clinicopathologic features and the role of HGF in ESCC. EXPERIMENTAL DESIGN: One hundred and forty-nine patients with ESCC were studied. Pretherapy serum was collected and ELISA was used to detect the concentrations of HGF, vascular endothelial growth factor (VEGF), and interleukin 8 (IL-8). The function of HGF was shown by invasion chamber assay. RESULTS: Pretherapy serum HGF was found to be significantly higher in patients with ESCC than in control subjects. The levels of HGF correlated significantly with advanced tumor metastasis stage and survival. Multivariate analyses showed that serum HGF level in cell migration was an independent prognostic factor. Increased HGF serum levels correlated positively with serum levels of VEGF and IL-8. Our results also showed that HGF was overexpressed in ESCC tissues and cell lines. In vitro study showed that HGF could stimulate ESCC cell to express VEGF and IL-8 and markedly enhance invasion and migration of ESCC cells. Furthermore, HGF-induced IL-8 and VEGF expression was dependent on extracellular signal-regulated kinase signaling pathways. The inhibition of extracellular signal-regulated kinase activation reduced HGF-mediated IL-8 and VEGF expression. CONCLUSIONS: Our results suggest that serum HGF may be a useful biomarker of tumor progression and a valuable independent prognostic factor in patients with ESCC. HGF may be involved in the progression of ESCC as an autocrine/paracrine factor via enhancing angiogenesis and tumor cell invasion and migration.