Comparison of intussusception pull-through end-to-side and conventional end-to-side microsurgical vasoepididymostomy: prospective randomized controlled study in male wistar rats

PURPOSE: Vasoepididymostomy is a technically challenging and complex microsurgical procedure. Recently a new triangulation end-to-side microsurgical technique was reported that allows intussusception of the epididymal tubule into the vasal lumen, resulting in a higher clinical patency rate of 92% with shorter operative time in preliminary clinical studies. We performed a prospective controlled randomized study comparing the patency rate, postoperative sperm granuloma rate and operating time of conventional and intussusception end-to-side vasoepididymostomy in previously vasectomized rats. MATERIALS AND METHODS: We randomized 42, 6-week-old male Wistar rats into 4 groups, including 6 into the sham operation, and 12 each into the control, conventional end-to-side and intussusception end-to-side vasoepididymostomy groups. Bilateral 2-clip vasectomy was performed in all animals except those in the sham operation group. Bilateral intussusception or conventional end-to-side vasoepididymostomy was performed in the assigned animals 2 weeks after vasectomy. Animals in the control group underwent vasectomy only. In the sham operation group the testes were mobilized out of the scrotum and then returned. Rats were sacrificed at 8, 12, 16 and 24 weeks, respectively. The anastomosis and vasectomy sites were inspected for sperm granuloma. To assess patency the abdominal end of the vas was transected and intraluminal fluid was examined microscopically at 400x magnification for the presence of motile sperm. Patency was further confirmed by performing retrograde indigo carmine vasography through the anastomoses. RESULTS: In the intussusception and conventional groups the patency rate was 91.7% and 54.2% (p = 0.004), the sperm granuloma rate was 20.8% and 58.4% (p = 0.035), and average operative time was 65.8 and 67.7 minutes (p = 0.197), respectively. CONCLUSIONS: Intussusception end-to-side vasoepididymostomy is superior to conventional end-to-side vasoepididymostomy with respect to the patency and postoperative sperm granuloma rates. Further investigations are required to confirm such findings clinically in humans.     

Domestication quantitative trait loci in Triticum dicoccoides,the progenitor of wheat

Wild emmer wheat, Triticum dicoccoides, is the progenitor of modern tetraploid and hexaploid cultivated wheats. Our objective was to map domestication-related quantitative trait loci (QTL) in T. dicoccoides. The studied traits include brittle rachis, heading date, plant height, grain size, yield, and yield components. Our mapping population was derived from a cross between T. dicoccoides and Triticum durum. Approximately 70 domestication QTL effects were detected, nonrandomly distributed among and along chromosomes. Seven domestication syndrome factors were proposed, each affecting 5-11 traits. We showed: (i) clustering and strong effects of some QTLs; (ii) remarkable genomic association of strong domestication-related QTLs with gene-rich regions; and (iii) unexpected predominance of QTL effects in the A genome. The A genome of wheat may have played a more important role than the B genome during domestication evolution. The cryptic beneficial alleles at specific QTLs derived from T. dicoccoides may contribute to wheat and cereal improvement.     

N-acetyl-l-cysteine sensitizes pancreatic cancers to gemcitabine by targeting the NFκB pathway

First-line therapy for pancreatic cancer is gemcitabine. Although tumors may initially respond to the gemcitabine treatment, soon tumor resistance develops leading to treatment failure. Previously, we demonstrated in human MIA PaCa-2 pancreatic cancer cells that N-acetyl-l-cysteine (NAC), a glutathione (GSH) precursor, prevents NFκB activation via S-glutathionylation of p65-NFκB, thereby blunting expression of survival genes. In this study, we documented the molecular sites of S-glutathionylation of p65, and we investigated whether NAC can suppress NFκB signaling and augment a therapeutic response to gemcitabine in vivo. Mass spectrometric analysis of S-glutathionylated p65-NFκB protein in vitro showed post-translational modifications of cysteines 38, 105, 120, 160 and 216 following oxidative and nitrosative stress. Circular dichroism revealed that S-glutathionylation of p65-NFκB did not change secondary structure of the protein, but increased tryptophan fluorescence revealed altered tertiary structure. Gemcitabine and NAC individually were not effective in decreasing MIA PaCa-2 tumor growth in vivo. However, combination treatment with NAC and gemcitabine decreased tumor growth by approximately 50%. NAC treatment also markedly enhanced tumor apoptosis in gemcitabine-treated mice. Compared to untreated tumors, gemcitabine treatment alone increased p65-NFκB nuclear translocation (3.7-fold) and DNA binding (2.5-fold), and these effects were blunted by NAC. In addition, NAC plus gemcitabine treatment decreased anti-apoptotic XIAP protein expression compared to gemcitabine alone. None of the treatments, however, affected extent of tumor hypoxia, as assessed by EF5 staining. Together, these results indicate that adjunct therapy with NAC prevents NFκB activation and improves gemcitabine chemotherapeutic efficacy.     

Ca2+ flux through voltage-gated channels with flow cessation in pulmonary microvascular endothelial cells

Objective: To investigate the role of voltage-gated Ca2+ channels in Ca2+ influx with flow cessation in flow-adapted rat pulmonary microvascular endothelial cells. Methods: Cells were evaluated for mRNA and protein levels for major components of the voltage-gated Ca2+ channels. Ca2+ influx with flow cessation and cell membrane potential were measured in real time with fluorescent dyes. Mibefradil and nifedipine were used as inhibitors of Ca2+ channel activity. Results: Voltage-gated Ca2+ channel protein and mRNA for the T-type channel were expressed at a relatively low level in endothelial cells cultured under static conditions and expression was induced significantly during flow adaptation. Flow-adapted but not control cells showed Ca2+ influx during flow cessation that was blocked by mibefradil but not by nifedipine. Ca2+ influx also was blocked by cromakalim, a KATP channel agonist. Cell membrane depolarization with flow cessation was unaffected by mibefradil. Conclusions: Rat pulmonary microvascular endothelial cells express T-type voltage-gated Ca2+ channels that are induced during adaptation to flow and are responsible for Ca2+ influx that occurs as a result of flow cessation-mediated membrane depolarization.     

Changes in Blood Lipid Levels following Silastic Ring Vertical Gastroplasty

Background The purpose of this study was to evaluate the effect of the Silastic Ring Vertical Gastroplasty (SRVG) operation on blood lipid levels in obese men and women during the first year following surgery. Methods 25 patients (11 men and 14 women) age 17–50 (mean 33 years) who suffered from morbid obesity (BMI > 40, range 45.9 ± 4.7 kg/m²) underwent SRVG. Blood samples were collected before operation and 3, 6 and 12 months following surgery and tested for: triglycerides, total cholesterol, HDL-C, LDL-C, VLDLC, and Lp(a). Results Both men and women lost weight significantly. Mean BMI decreased from 48.0 to 32.5 kg/m² in men and from 44.3 to 29.0 kg/m² in women (P < 0.01). Blood lipid levels 1 year following surgery demonstrated the following changes: In women, triglycerides, total cholesterol, LDL, VLDL cholesterol and Lp(a) decreased from 160.7 mg/dL to 67.7 mg/dL (P < 0.01), from 220 mg/dL to 189 mg/dL, from 138.3 mg/dL to 111 mg/dL, from 17 mg/dL to 12 mg/dL, and from 77.5 mg/dL to 18.5 mg/dL (P < 0.01), respectively, and HDL increased from 45 mg/dL to 50.5 mg/dL. In men, triglycerides, total cholesterol, LDL, VLDL cholesterol and Lp(a) decreased from 246 mg/dL to 140 mg/dL (P < 0.01), from 206 mg/dL to 170 mg/dL (P < 0.01), from 134 mg/dL to 112 mg/dL (P < 0.05), from 25 mg/dL to 15 mg/dL (P < 0.01), and from 30.3 mg/dL to 11.6 mg/dL (P < 0.01), respectively, and HDL increased from 31.3 mg/dL to 37.4 mg/dL (P < 0.05). Conclusion SRVG improved blood lipid profile in obese patients during the first year following surgery. Reduction in cholesterol and its fractions reaches statistical significance only in men.     

Sympathectomy-like effects of brachial plexus block in arteriovenous access surgery

We used color Doppler ultrasonography to prospectively study the effects of supraclavicular brachial plexus block (BPB) on blood flow and vein diameter in patients undergoing arteriovenous access surgery. BPB might produce a sympathectomy-like effect that could have a role in improving patencty. Thirty-one consecutive patients who underwent arteriovenous access surgery with BPB were studied prospectively, in addition to 5 patients with BPB having other operations and 5 patients undergoing general anesthesia for elective surgery. Vessel diameter and pulsatility index (PI) were among the parameters measured. Mean PI decreased from 6.18 +/- 1.67 before the block to 3.92 +/- 1.75 at 10 min after initiation of the block (p = 0.001). Basilic vein diameter increased from 6.28 +/- 0.86 mm (range 4.85 to 7.30) before the block to 7.83 +/- 1.52 mm (range 5.80 to 12.14) 10 min after the block (p = 0.03). In the general anesthesia control group the PI decreased, but returned to preanesthetic levels immediately after the patients reached the recovery room. In the nonaccess BPB group the PI remained low after the block for at least 5 h. Brachial plexus block causes significant venous dilation and a significant decrease in the pulsatility index. This appears to be due to a beneficial sympathectomy-like effect of the block that might prevent early failure and improve patency in vascular access surgery.     

Cellular resistance to a nitric oxide releasing glutathione S-transferase P-activated prodrug,PABA/NO

PABA/NO is a diazeniumdiolate selectively activated by glutathione S-transferase P (GSTP) to release nitric oxide (NO) and is a potent inducer of protein S-glutathionylation, a redox-sensitive post-translational modification of cysteine residues. Using a procedure that incrementally increased exposure of cells to PABA/NO, an acquired drug resistant human promyelocytic leukemia HL60 cell line (HL60^PABA) that exhibited 1.9-fold resistance to the drug (IC₅₀ ∼15 μM vs ∼8 μM for wild-type) was created. HL60^PABA cells had a decreased growth rate attributable to altered cellular differentiation, as measured by increased expression of CD11b; decreased expression of CD14; decreased nuclear to cytoplasmic ratios and a condensation of nuclear chromatin. This was accompanied by alterations in both plasma and mitochondrial membrane potentials. Both GSTP expression and nitric oxide release were reduced two-fold, while increased expression levels of genes involved in the unfolded protein response (UPR) were evident in HL60^PABA cells. Wild type cells treated with PABA/NO had increased levels of protein S-glutathionylation and JNK activation, while JNK was constitutively active in HL60^PABA cells and these cells had reduced levels of S-glutathionylation. By removing PABA/NO from the growth medium, HL60^PABA cells reverted to sensitivity within 21 days suggesting that resistance was not genetically stable. Mechanistically, PABA/NO resistance is mediated through reduced levels of GSTP resulting in reduced NO release and its subsequent alterations in cellular response to nitrosative stress.