Preparation of ABCBA-type block copolymers by use of macro-initiators containing peroxy and azo groups

Some new macroinitiators ( 5 ) containing azo and peroxy groups were synthesized by transformation of esters of poly(ethylene glycol) ( 1 ) (PEG) of different molecular weight with hydroxyl end groups and an azo group in the middle into the corresponding polymers with tert-butylperoxycarbonyl end groups by reaction with terephthaloyl chloride and subsequently with tert-butyl hydroporoxide. Decomposition in the presence of styrene at 60°C or with 3,6,9-triazaun-decane-1,11-diamine in presence of methyl methacrylate gave the corresponding ABA block copolymer 6 and the ABBA block copolymer 7 , respectively. Both block copolymers were used as polymeric initiators. The ABCBA block copolymer 8 was synthesized from 6 and methyl methacrylate or from 7 and styrene by thermally induced polymerization at 80°C. The resulting block copolymers were separated from the homopolymers by selective solvent extraction and characterized by spectroscopic and fractional precipitation methods.     

Sequence analysis of rpoB mutations in rifampin-resistant clinical Mycobacterium tuberculosis isolates from Turkey

Drug-resistant tuberculosis is a serious problem throughout the world. Resistance to Rifampicin (RIF) is mainly caused by the mutations in the rpoB gene coding the beta-subunit of RNA polymerase. In this study, we aimed to detect the distribution of rpoB gene mutations in 80 RIF-resistant clinical Mycobacterium tuberculosis (MTB) isolates from Turkey. The rpoB gene was amplified by PCR and mutations leading to RIF resistance were determined by automated sequence analysis. A total of 72 of the 80 isolates (90%) were found to carry mutations in the amplified region, whereas eight isolates (10%) carried no mutations. Overall, 24 different missense mutations affecting 14 codons, and two deletion mutants were identified. Nine new mutations, six in the hot-spot region and three outside this region, were found. The codon numbers of the most frequently encountered mutations were 531 (51.4%), 526 (18.1%), 516 (13.9%), and 513 (12.5%). As a result, 90% of the RIF-resistant MTB isolates from the Turkish patients were found to carry a mutation in the rpoB gene, Ser531Leu being the most frequent one. Although molecular methods identify mutations leading to RIF resistance very quickly, results of the antimycobacterial susceptibility tests must be taken into consideration for the patients carrying no mutations in this region.     

Susceptibilities of Mycobacterium tuberculosis to isoniazid and rifampin on blood agar

In this study, blood agar was used instead of 7H10 agar for the susceptibility testing of 34 clinical isolates of Mycobacterium tuberculosis to isoniazid (INH) and rifampin (RIF) in accordance with the NCCLS. The BACTEC 460 TB system (Becton Dickinson, Sparks, Md.) was used as a "gold standard." Results for both media were in agreement for RIF and INH at 100 and 94.1%, respectively. For INH, the specificity, sensitivity, positive predictive value, and negative predictive value were found to be 71.4, 100, 93.1, and 100%, respectively, while these values were 100% for RIF. In addition, the results of the susceptibility test performed with blood agar were obtained on day 14 of incubation. In conclusion, results were obtained much earlier with blood agar (2 weeks) than with 7H10 agar (3 weeks), and the results of this study suggest that blood agar may be used as an alternative medium for the susceptibility testing of M. tuberculosis to INH and RIF.     

Diagnosis of gastric carcinoma by classification on feature projections

A new classification algorithm, called benefit maximizing classifier on feature projections (BCFP), is developed and applied to the problem of diagnosis of gastric carcinoma. The domain contains records of patients with known diagnosis through gastroscopy results. Given a training set of such records, the BCFP classifier learns how to differentiate a new case in the domain. BCFP represents a concept in the form of feature projections on each feature dimension separately. Classification in the BCFP algorithm is based on a voting among the individual predictions made on each feature. In the gastric carcinoma domain, a lesion can be an indicator of one of nine different levels of gastric carcinoma, from early to late stages. The benefit of correct classification of early levels is much more than that of late cases. Also, the costs of wrong classifications are not symmetric. In the training phase, the BCFP algorithm learns classification rules that maximize the benefit of classification. In the querying phase, using these rules, the BCFP algorithm tries to make a prediction maximizing the benefit. A genetic algorithm is applied to select the relevant features. The performance of the BCFP algorithm is evaluated in terms of accuracy and running time. The rules induced are verified by experts of the domain.     

Preoperative embolization in surgical treatment of a primary hemangiopericytoma of the rib: a case report

Primary hemangiopericytoma of the rib is extremely rare and only a few cases have been reported. A 62-yr-old man presented with an aching chest pain and dyspnea. Thoracic computed tomography revealed a homogenous mass expanding the right seventh rib. A diagnosis of hemangiopericytoma was established by percutaneous needle biopsy. Preoperative embolization of the feeding vessels of the tumor was performed in order to prevent perioperative bleeding. There was no significant bleeding during the surgery, where complete resection of the tumor with 7th to 9th ribs with a surgical margin of 5 cm was performed. Postoperative course was uneventful and there has been no recurrence for thirteen months. To our knowledge, there has been no report to apply a preoperative embolization of a primary hemangiopericytoma of the rib.     

A cluster of nosocomial Klebsiella oxytoca bloodstream infections in a university hospital.

BACKGROUND: On February 19, 2003, four patients (patients 1-4) in the neurology ward underwent cranial magnetic resonance angiography (MRA) and developed fever within 1 hour afterward. Klebsiella oxytoca was isolated from blood cultures of patients 1 through 3. OBJECTIVE: To identify the source of this cluster of nosocomial K. oxytoca bloodstream infections. DESIGN: Outbreak investigation. SETTING: A 1,000-bed university hospital. METHODS: The infection control team reviewed patient charts and interviewed nursing staff about the preparation and administration of parenteral fluids. The procedure of cranial MRA was observed. Arbitrarily primed polymerase chain reaction (AP-PCR) was performed to show the clonal relationship among these three strains. RESULTS: AP-PCR revealed that three K. oxytoca isolates had the same molecular profile. Cranial MRA was found to be the only common source among these patients. During MRA, before injection of the contrast medium, normal saline solution was infused to check the functioning of the intravenous catheter. Use of the solution for multiple patients was routine, but the access diaphragm of the bottle was not cleansed. The bottle of normal saline solution used on February 19 had already been discarded and the culture sample taken from the solution on the day of observation was sterile. CONCLUSIONS: We speculate that normal saline solution became contaminated during manipulation and that successive uses might have been responsible for this cluster. Poor aseptic techniques employed during successive uses appear to be the most likely route of contamination. Use of parenteral solutions for multiple patients was discontinued.     

Ischemia-modified albumin levels in children having seizure

Convulsions are one of the frequently seen problems for a neurologist in the daily routine. It is difficult to distinguish the seizure from pseudo-seizure because of lack of conclusive tests. The aim of this study is to investigate the relationship between seizure types and seizure periods by studying IMA serum levels in children having seizure. Two groups were included (patients and control) in our study. The patient group consisted of the children admitted to Pediatric Emergency Care during January 2008–January 2010 with seizure and the control group consisted of healthy children. Serum Ischemia modified albumin (IMA) level in the group having seizures was 99.7 and 83.2 U/ml in the control group. In the comparison of the patient and control groups, significant differences were found between their IMA values (p = 0.000). There was a significant difference between IMA values of the group having generalized tonic–clonic seizures and those of the control group (p = 0.001). In comparison of the IMA values of the group having febrile convulsions and those of the control group, a significant difference was determined (p = 0.011). It has been shown that if the seizure was prolonged over 5 min, IMA level increased, and there was a significant difference between the groups experiencing over 5 min of seizures and the groups experiencing less than 5 min of seizures (p = 0.001). An increase in IMA levels in febrile convulsion supports the hypoxia development in the brain during the seizure. Serum IMA levels increased with the elongation of the seizure period and may be an indicator for status epilepticus.