Balance algorithm for cluster randomized trials

Background  

Within cluster randomized trials no algorithms exist to generate a full enumeration of a block randomization, balancing for covariates across treatment arms. Furthermore, often for practical reasons multiple blocks are required to fully randomize a study, which may not have been well balanced within blocks.     

Safety evaluation of surgical materials by cytotoxicity testing

The cytotoxicity of three kinds of commercially available absorbable hemostats [oxidized cellulose (Surgicel, gauze and cotton types), microfibrillar collagen (Avitene), and cotton-type collagen (Integran)] and one adhesion barrier [sodium hyaluronate and carboxymethyl-cellulose membrane (Seprafilm)] were comparatively assessed by a colony assay using V79 cells and a minimum essential medium (MEM) elution assay in combination with a neutral red assay using L929 cells. Strong cytotoxicity was detected for Surgicel by both the MEM elution assay and the colony assay. For Avitene, both methods revealed weak cytotoxicity. For Seprafilm, no cytotoxicity was detected by the MEM elution assay, while a moderate degree of cytotoxicity was observed in the colony assay. For Integran cytotoxicity was not detected by either the MEM elution or the colony assay. The results of the different methods showed some inconsistency in terms of the degree of cytotoxicity of the materials. It is proposed that the combination of two or more sensitive cytotoxicity testing methods for the evaluation of biomaterials is necessary to avoid false-negative results for biomaterials at the preclinical stage. Furthermore, investigation of the correlation between the cytotoxicity and the extraction period of the surgical materials is helpful for predicting the effect of prolonged in vivo use of biomaterials on surrounding cells, tissues, and organs.     

Progressive myelopathy due to meningeal thickening in shunted patients: description of a novel entity and the role of surgery

INTRODUCTION: Spinal cord compression due to meningeal thickening is a rare occurrence in shunted patients. Because of the long delay to clinical onset, this complication has not been identified as yet. AIMS: We report on nine cases of shunt-related progressive myelopathy due to meningeal thickening (SPMMT). MATERIALS AND METHODS: We reviewed our database of shunted children, for cases having developed progressive tetraparesis due to cervical meningeal thickening. RESULTS: We identified nine observations of SPMMT, eight of these with hydrocephalus due to neonatal meningitis; the last case had Dandy-Walker malformation shunted at birth and suffered postoperative meningitis. The age of clinical onset of myelopathy was between 6 and 20 years (median 12.8). All patients presented with slowly progressive walking difficulties with falls and no spinal pain. Magnetic resonance imaging (MRI) showed typically a thickened dura mater with collapse of the arachnoid space, compensatory expansion of the epidural fat, and T2 hyperintensity in the spinal cord. We operated on seven patients for surgical decompression and arachnoidolysis: One died postoperatively because of shunt malfunction, and two others died later of complications of tetraplegia. Three patients were aggravated after surgery, three experienced partial improvement, but one of these subsequently deteriorated again. CONCLUSION: SPMMT appears to be a novel and well-defined clinical and pathological entity; its pathological and radiological features are stereotyped; however, the diagnosis is delayed because of the slow pace of the disease. Although surgical decompression may be the only option, its results were poor in our experience; earlier surgery might improve this grim prognosis.     

Lack of evidence for fecal-oral transmission of Helicobacter pylori infection in Taiwanese.

BACKGROUND AND PURPOSE: Helicobacter pylori infection is primarily acquired in early childhood and its transmission routes are debated. The aims of this study were to determine the seroprevalence of anti-H. pylori immunoglobulin G (IgG) in Taiwanese and to investigate whether a common mode of transmission could be shared between H. pylori and hepatitis A virus (HAV). METHODS: An enzyme-linked immunosorbent assay (ELISA) was used to investigate the prevalence of H. pylori among 924 healthy volunteers aged less than 40 years, and radioimmunoassay for HAV infection was conducted in 500 subjects from the same population. The kappa statistic was used to measure the difference in positivity for the 2 infections in a subgroup of 500 subjects who had their sera simultaneously tested for anti-H. pylori and anti-HAV antibodies. RESULTS: The seroprevalence of anti-H. pylori IgG was 16.7% in subjects aged < 16 years and 38.3% at ages >or= 16 years. Most children (99%) under the age of 16 were seronegative for HAV. The prevalence of H. pylori infection increased rapidly with age, at 1%/year and 0.8%/year for children and adults, respectively. The rate of H. pylori infection was higher in male (21%) than in female (12%) children (p < 0.01; OR, 2.0; 95% confidence interval, 1.2 to 3.0). No significant difference in seroprevalence between genders was noted in subjects aged >or= 16 years. The agreement in the trend of seropositivity between both infections in the age groups 1 to 10 years and 10 to 20 years was worse than chance (kappa = -0.56) and little better than chance (kappa = 0.01), respectively. CONCLUSIONS: Acquisition of H. pylori infection occurs at a young age, and male children are more likely to develop the infection. The main transmission route of HAV, the fecal-oral route, did not seem to be responsible for H. pylori transmission in this Taiwanese cohort.     

An automated on-line method for simultaneous analysis of phenothiazines in human serum by high-performance liquid chromatography/sonic spray ionization mass spectrometry using backflush column switching

An automated on-line method for simultaneous analysis of five phenothiazine drugs by high-performance liquid chromatography (HPLC)/sonic spray ionization mass spectrometry (SSI-MS) has been established, using backflush column switching. A 400-μl portion of serum sample diluted 81-fold with distilled water was subjected to the on-line system. In the system, an Oasis HLB cartridge was used as the precolumn for extraction; large molecules such as proteins in serum were discarded by use of distilled water containing 0.1% formic acid as a mobile phase. After switching a valve, the analytes trapped in the precolumn were eluted in the backflush mode and separated by a Chromolith Performance RP-18e column, which is composed of C₁₈-bonded monolithic silica. The column effluents were then introduced into the SSI-MS. The present method provided successful separation and determination of six phenothiazines including an internal standard. Satisfactory linearities, reproducibility, and sensitivity were obtained at concentration levels that matched the toxic levels of phenothiazines. All drug peaks appeared within 18 min, and the system could be reequilibrated in only about 8 min for the next run. Because of the simplicity and rapidness of the method, it is likely to be useful in the fields of emergency medicine and forensic toxicology.     

人毛乳头细胞条件培养液治疗斑秃的临床观察

目的：人毛乳头细胞条件培养液治疗斑秃患者的临床观察。方法：用人毛乳头细胞条件培养液治疗100例斑秃患者，并分别选择其中53例和30例作去炎松组和空白组自身对照。结果：人毛乳头细胞条件培养液组、去炎松组和空白组治愈率分别为75％、51％、10％，有效率分别为97％、72％、30％，人毛乳头细胞条件培养液组其治愈率和有效率均明显高于去炎松组和空白组（P〈0．05）。结论：人毛乳头细胞条件培养液对斑秃患者有明显的治疗作用。     

Trends and Predictors for Vagotomy When Performing Oversew of Acute Bleeding Duodenal Ulcer in the United States

Background In the era of Helicobacter pylori treatment, the role of vagotomy in bleeding duodenal ulcers is debatable. National outcomes were evaluated to determine the current surgical treatment and use of vagotomy for bleeding duodenal ulcers. Methods Data from the Nationwide Inpatient Sample (NIS) were used from years 1999 to 2003. Patients were selected using diagnostic codes for acute duodenal ulcer bleed and procedure codes for simple oversew of a bleeding ulcer and vagotomy. Data were analyzed using multiple linear and logistic regression. Results Between 1999 and 2003, 100,931 patients with an acute bleeding duodenal ulcer were identified. Over time, there was a decrease in the number of acute bleeding ulcers (p = 0.027) and a decrease in the number of vagotomies (p = 0.027). A high co-morbidity index [odds ratio (OR), 0.60, p = 0.017], operation in the Midwest (OR 0.50, p < 0.001) and operation in the West (OR 0.68, p = 0.034) were predictive of no vagotomy during surgery for a bleeding duodenal ulcer. Conclusions A vagotomy is not commonly performed during surgical treatment of an acute bleeding duodenal ulcer. This variation in practice was not fully explained by patient characteristics. We must seek new evidence to determine the safety of combined medical and surgical management of this clinical problem. Presented at DDW/SSAT May 20–24, Los Angeles, California.     

Less invasive Achilles tendon reconstruction

Background  

The optimal management of chronic ruptures of the Achilles tendon is surgical reconstruction. Reconstruction of the Achilles tendon using peroneus brevis has been widely reported. Classically, these procedures involve relatively long surgical wounds in a relatively hypovascular area which is susceptible to wound breakdown.     

Quantifying the blood oxygenation level dependent effect in cerebral blood volume-weighted functional MRI at 9.4T.

In cerebral blood volume (CBV)-weighted functional MRI (fMRI) employing superparamagnetic contrast agent, iron dose and blood oxygenation level dependent (BOLD) contamination are two important issues for experimental design and CBV quantification. Both BOLD and CBV-weighted fMRI are based upon the susceptibility effect, to which spin-echo and gradient-echo sequences have different sensitivities. In the present study, CBV-weighted fMRI was conducted using spin-echo and gradient-echo sequences at 9.4T by systematically changing the doses of contrast agent. Results suggest that BOLD contamination is a significant component in CBV-weighted fMRI at high field, particularly when relatively low dose of contrast agent is administered. A mathematical model was developed to quantify the extravascular (EV) BOLD effect. With a TE of 35 ms, the EV BOLD effect was estimated to account for 76+/-12% of the observed spin-echo fMRI signal at 9.4T. These data suggest that correcting BOLD effect may be necessary for accurately quantifying activation-induced CBV changes at high field.     

Arthroscopic tarsometatarsal (Lisfranc) arthrodesis

We describe an arthroscopic approach of tarsometatarsal arthrodesis for post-traumatic arthritis. Five tarsometatarsal portals (medial, P1–2, P2–3, P3–4, P4–5) are identified at the junctional points between the metatarsals by means of image intensifier. The first metatarsocuneiform joint is approached through the medial and P1–2 portal. Articular cartilage is denuded and micro-fracture of subchondral bone is performed with an arthroscopic awl. The second metatarsocuneiform joint is approached through the P1–2 and P2–3 portals and the third metatarsocuneiform joint is approached through the P2–3 and P3–4 portals. The articular surfaces are prepared for arthrodesis. The articulations are kept in desired position and transfixed with 4.0 mm cannulated screws. The fourth and fifth metatarsocuboid articulations are rarely included in the procedure. Arthroscopic arthrodesis or tendon arthroplasty of the lateral column can be performed through the P3–4 and P4–5 portals.