Observational study of the efficacy of supraclavicular brachial plexus block for arteriovenous fistula creation.

BACKGROUND AND AIMS: Arteriovenous (AV) fistula surgery is commonly performed for AV access for hemodialysis. However the ideal anaesthetic technique of choice remains debated. We aimed to assess operative conditions, vascular patency, and complication rate following AV fistula surgery with isolated brachial plexus block among end-stage renal disease (ESRD) patients. METHODS: This prospective, observational study included 214 patients undergoing AV fistula surgery under isolated supraclavicular brachial plexus block between January and December 2017. The diameters of the vessels both before and after the block, and the patency of the AV fistula in the immediate postoperative period and after 3 months were assessed using ultrasound Doppler. The change in the vessel diameter both before and after block was compared using independent sample t-test. RESULTS: The mean brachial artery diameter increased by 0.09 mm (P = 0.002), and cephalic vein diameter at elbow, radial artery, and cephalic vein at wrist diameters increased by 0.5 mm (P < 0.001), 0.08 mm (P = 0.031), and 0.48 mm (P < 0.001), respectively. Overall, 93.45% had immediate patency, 85.51% had primary, and 47.19% had functional patency at 3 months. In the brachiocephalic group, 96.24% had immediate patency, 87.21% had primary, and 27.06% had functional patency at 3 months. Among the radiocephalic group, 91.35% had immediate patency, 82.71% had primary patency, and 71.60% had functional patency at 3 months. CONCLUSION: Ultrasound-guided isolated brachial plexus block results in good vasodilation and achieves good immediate and long-term patency in AV fistula surgery.

An unusual case of foreskin phimosis after radiotherapy for rectal carcinoma.

Phimosis of the foreskin after radiotherapy for rectal carcinoma is extremely rare and has previously been described only once (2006) in the English-language literature. Combination chemo/radiotherapy is currently the treatment of choice and widely used in the management of various pelvic malignancies. In this report, we describe a rare complication on male genitalia following the radiotherapy for lower rectal cancers. Few days following the completion of radiotherapy, patient developed phimosis of the foreskin, which was successfully treated medically without the need for circumcision. Radiotherapy can bring a great risk of injury to anorectum and its adjacent structures. Risk of phimosis should be considered under the current radiation guidelines and we support the concept of using penile shielding for all radiotherapy procedures in colorectal carcinoma patients.

Single nucleotide polymorphisms and mRNA expression of VEGF-A in papillary thyroid carcinoma: potential markers for aggressive phenotypes.

BACKGROUND AND OBJECTIVES: Polymorphisms of the VEGF gene are known to affect the biological behaviour of cancers but have seldom been studied in thyroid cancer. The aim of the current study is to evaluate the prevalence and relevance of VEGF-A polymorphisms and mRNA expression in papillary thyroid carcinoma (PTC). MATERIALS AND METHODS: Genomic DNA and total RNA were isolated from paraffin-embedded tissue from 91 PTC (51 conventional PTC and 40 follicular variant) and 78 control thyroid tissues. Three DNA polymorphisms (+936C > T, +405C > G and -141A > C) in the 3' and 5' untranslated region (3'-UTR, 5'-UTR) of VEGF-A were studied using PCR and RFLP. Also, the mRNA expression of VEGF-A in these tissues was studied by real-time PCR. RESULTS: Distribution of polymorphisms in the 5'-UTR (VEGF-VEGF -141A > C and +405C > G) and 3'-UTR (VEGF +936C > T) were all significantly different in PTC and benign thyroid tissue (p = 0.0001, 0.001 and 0.028 respectively). The VEGF -141 C allele was more common in PTC with lymph node metastases (p = 0.026). VEGF + 405 Galleles andVEGF +936 CC genotype were more common in PTC of advanced pathological staging (p = 0.018 and 0.017 respectively). Also, increased expression of VEGF-A mRNA was noted in PTC compared to control (p = 0.009). Within the group of patients with conventional PTC, those with lymph nodal metastases had a higher level of VEGF-A mRNA expression than other patients (p = 0.0003). CONCLUSION: These findings suggest that VEGF polymorphisms and mRNA expression may predict the aggressiveness behaviour of thyroid cancer.

Long term follow-up of patients with polycystic ovarian syndrome after laparoscopic ovarian drilling: clinical outcome.

BACKGROUND: Currently, there is an uncertainty about the impact of laparoscopic ovarian drilling (LOD) on the natural history of polycystic ovarian syndrome (PCOS). This longitudinal follow-up study was undertaken to investigate the long-term effects of LOD. METHODS: The study included 116 anovulatory PCOS women who underwent LOD between 1991 and 1999 (study group) and 34 anovulatory PCOS women diagnosed during the same period but who had not undergone LOD (comparison group). The hospital records were reviewed and questionnaires were sent to all the women. In addition, most women attended a follow-up interview. Clinical data recorded at different intervals of follow-up (short-term, <1 year; medium-term, 1-3 years; and long-term, 4-9 years) included: the menstrual pattern, symptoms relating to hyperandrogenaemia and reproductive history. RESULTS: The proportion of women with regular menstrual cycles increased significantly [relative risk (RR) = 1.6, 95% confidence interval (CI) = 1.4-1.9, P < 0.05] from 8% before LOD to 67% post-operatively. The proportion dropped to 37% (RR = 2.6, 95% CI = 1.8-3.8, P < 0.01) at medium-term follow-up and then increased again to 55% (RR = 2.2, 95% CI = 1.7-2.8, P < 0.01) at long-term follow-up. After LOD, 54/110 women (49%) conceived spontaneously during the first year and 42 (38%) during medium- and long-term follow-up. Among women with hirsutism (n = 43) and acne (n = 25), 10 (23%) and 10 (40%) respectively experienced long-term improvement after LOD. CONCLUSION: LOD produces long-term improvement in menstrual regularity and reproductive performance in about one-third of cases. A modest and sustained improvement in acne and hirsutism can be expected in approximately 40 and approximately 25% of patients respectively.

Use of EPR spectroscopy to study macromolecular structure and function.

Electron paramagnetic resonance (EPR) spectroscopy is now part of the armory available to probe the structural aspects of proteins, nucleic acids and protein-nucleic acid complexes. Since the mobility of a spin label covalently attached to a macromolecule is influenced by its microenvironment, analysis of the EPR spectra of site-specifically incorporated spin labels (probes) provides a powerful tool for investigating structure-function correlates in biological macromolecules. This technique has become readily amenable to address various problems in biology in large measure due to the advent of techniques like site-directed mutagenesis, which enables site-specific substitution of cysteine residues in proteins, and the commercial availability of thiol-specific spin-labeling reagents (Figure 1). In addition to the underlying principle and the experimental strategy, several recent applications are discussed in this review.

Mapping RNA-protein interactions in ribonuclease P from Escherichia coli using disulfide-linked EDTA-Fe.

The protein subunit of Escherichia coli ribonuclease P (which has a cysteine residue at position 113) and its single cysteine-substituted mutant derivatives (S16C/C113S, K54C/C113S and K66C/C113S) have been modified using a sulfhydryl-specific iron complex of EDTA-2- aminoethyl 2-pyridyl disulfide (EPD-Fe). This reaction converts C5 protein, or its single cysteine-substituted mutant derivatives, into chemical nucleases which are capable of cleaving the cognate RNA ligand, M1 RNA, the catalytic RNA subunit of E. coli RNase P, in the presence of ascorbate and hydrogen peroxide. Cleavages in M1 RNA are expected to occur at positions proximal to the site of contact between the modified residue (in C5 protein) and the ribose units in M1 RNA. When EPD-Fe was used to modify residue Cys16 in C5 protein, hydroxyl radical-mediated cleavages occurred predominantly in the P3 helix of M1 RNA present in the reconstituted holoenzyme. C5 Cys54-EDTA-Fe produced cleavages on the 5' strand of the P4 pseudoknot of M1 RNA, while the cleavages promoted by C5 Cys66-EDTA-Fe were in the loop connecting helices P18 and P2 (J18/2) and the loop (J2/4) preceding the 3' strand of the P4 pseudoknot. However, hydroxyl radical-mediated cleavages in M1 RNA were not evident with Cys113-EDTA-Fe, perhaps indicative of Cys113 being distal from the RNA-protein interface in the RNase P holoenzyme. Our directed hydroxyl radical-mediated footprinting experiments indicate that conserved residues in the RNA and protein subunit of the RNase-P holoenzyme are adjacent to each other and provide structural information essential for understanding the assembly of RNase P.

Mapping RNA-protein interactions in ribonuclease P from Escherichia coli using electron paramagnetic resonance spectroscopy.

Ribonuclease P (RNase P) is a catalytic ribonucleoprotein (RNP) essential for tRNA biosynthesis. In Escherichia coli, this RNP complex is composed of a catalytic RNA subunit, M1 RNA, and a protein cofactor, C5 protein. Using the sulfhydryl-specific reagent (1-oxyl-2,2,5, 5-tetramethyl-Delta3-pyrroline-3-methyl)methanethiosulfonate (MTSL), we have introduced a nitroxide spin label individually at six genetically engineered cysteine residues (i.e., positions 16, 21, 44, 54, 66, and 106) and the native cysteine residue (i.e., position 113) in C5 protein. The spin label covalently attached to any protein is sensitive to structural changes in its microenvironment. Therefore, we expected that if the spin label introduced at a particular position in C5 protein was present at the RNA-protein interface, the electron paramagnetic resonance (EPR) spectrum of the spin label would be altered upon binding of the spin-labeled C5 protein to M1 RNA. The EPR spectra observed with the various MTSL-modified mutant derivatives of C5 protein indicate that the spin label attached to the protein at positions 16, 44, 54, 66, and 113 is immobilized to varying degrees upon addition of M1 RNA but not in the presence of a catalytically inactive, deletion derivative of M1 RNA. In contrast, the spin label attached to position 21 displays an increased mobility upon binding to M1 RNA. The results from this EPR spectroscopy-based approach together with those from earlier studies identify residues in C5 protein which are proximal to M1 RNA in the RNase P holoenzyme complex.

Schistosomiasis: an unusual cause of right lower quadrant abdominal pain.

Schistosomiasis, although unusual in North America, is a common disease worldwide. Symptoms vary depending on the species involved. Immigrants from endemic regions are the commonly affected patients found in North America. In most cases, schistosomiasis does not present with right lower quadrant pain. Even in endemic regions, this form of presentation is uncommon. In the United States, most cases of right lower quadrant pain often will be treated as appendicitis. Questions remain unanswered as to whether the schistosomes cause appendicitis or are found incidentally in these cases. Stool and urine specimens may be helpful in making a diagnosis. Most cases require operative intervention to rule out appendicitis and to obtain tissue for histopathologic diagnosis. Praziquantel is effective in eradicating infestations.

Use of 4-heptylumbelliferyl-beta-D-glucoside to identify Gaucher's disease heterozygotes.

Three fluorometric beta-glucosidase assays were compared for their ability to identify Gaucher's disease heterozygotes, using leukocytes as the source of enzyme: the pH 5.5-taurocholate assay of Peters et al.; the conduritol B epoxide dependent variation of that assay; and the newly developed method described herein. While the first two procedures utilize the standard substrate 4-methylumbelliferyl-beta-D-glucopyranoside to estimate beta-glucosidase activity, the new assay uses 4-heptylumbelliferyl-beta-D-glucoside as (C7UGlc) substrate. Use of this substrate enhances the specificity of the method for lysosomal glucocerebrosidase, thereby minimizing the contribution of the nonspecific cytosolic beta-glucosidase to estimates of substrate hydrolysis. Using Student's t test for the three assays examined, the C7UGlc assay procedure was determined to have the lowest p value (p less than 0.001) and highest t value (t = 4.95) for the discrimination between the mean glucocerebrosidase value of control and obligate Gaucher heterozygote samples. The high reliability and simplicity of the C7UGlc assay lends adequate reason to favor this assay for regular clinical diagnosis of Gaucher heterozygotes.