N-substituted benzimidazole acrylonitriles as in vitro tubulin polymerization inhibitors: Synthesis, biological activity and computational analysis.

We present the design, synthesis and biological activity of novel N-substituted benzimidazole based acrylonitriles as potential tubulin polymerization inhibitors. Their synthesis was achieved using classical linear organic and microwave assisted techniques, starting from aromatic aldehydes and N-substituted-2-cyanomethylbenzimidazoles. All newly prepared compounds were tested for their antiproliferative activity in vitro on eight human cancer cell lines and one reference non-cancerous assay. N,N-dimethylamino substituted acrylonitriles 30 and 41, bearing N-isobutyl and cyano substituents placed on the benzimidazole nuclei, showed strong and selective antiproliferative activity in the submicromolar range of inhibitory concentrations (IC50 0.2-0.6 µM), while being significantly less toxic than reference systems docetaxel and staurosporine, thus promoting them as lead compounds. Mechanism of action studies demonstrated that two most active compounds inhibited tubulin polymerization. Computational analysis confirmed the suitability of the employed benzimidazole-acrylonitrile skeleton for the binding within the colchicine binding site in tubulin, thus rationalizing the observed antitumor activities, and demonstrated that E-isomers are active substances. It also provided structural determinants affecting both the binding position and the matching affinities, identifying the attached NMe2 group as the most dominant in promoting the binding, which allows ligands to optimize favourable cation∙∙∙π and hydrogen bonding interactions with Lys352.

Evaluation of indirect decompression of the lumbar spinal canal following minimally invasive lateral transpsoas interbody fusion: radiographic and outcome analysis.

BACKGROUND: The surgical treatment of lumbar stenosis traditionally includes laminectomy for direct decompression of the spinal canal. Selected patients with spinal stenosis may also require lumbar fusion. Minimally invasive lateral transpsoas interbody fusion has the ability of placing a large interbody cage that can increase disc height and distract the spinal level. The purpose of this study was to examine the concept of indirect decompression of the spinal canal in patients with co-existing lumbar spinal stenosis undergoing lateral transpsoas interbody fusion. MATERIALS AND METHODS: We reviewed 25 consecutive spinal stenosis patients with instability undergoing lateral transpsoas interbody fusion without laminectomy. All patients had relevant symptoms of back pain, leg pain, and/or spinal claudication and met standard criteria for lumbar fusion. Patients were evaluated by outcome analysis scales (VAS scores, Oswestry disability index and treatment intensity scale). Postoperative MRI scans, when available, were evaluated for change in canal dimensions. Statistical significance was assessed by paired t-test, which compares the mean change. There were 25 patients in the study (mean age 61 years). 15 patients had grade I spondylolisthesis. VAS for back pain intensity improved from 7.74 to 2.07 and for frequency from 7.91 to 2.22. VAS for leg pain intensity improved from 7.24 to 1.87 and frequency from 7.41 to 2.35. All improvements were statistically significant (P<0.0001). The Oswestry disability index improved from 55.1 to 16.4 (P<0.0001), and treatment intensity scale improved from 14.6 to 3.7 (P<0.0001). Radiographic evaluation in 20 treated levels (15 patients) found an increase in dural sac dimension of 54% in the anterior-posterior plane and 48% in the medial-lateral plane (P<0.0001). The calculated area of the dural sac increased an average of 143% (range of - 10.4% to + 495%). CONCLUSION: Indirect decompression of spinal stenosis can be achieved with lateral transpsoas interbody fusion with improved clinical outcomes. Pre-op and post-op MRI scans showed a significant increase in dural sac dimensions. The mechanism for this indirect decompression may relate to stretching and unbuckling of the spinal ligaments and a decrease in intervertebral disc bulging. Further studies are needed to determine which stenosis patients undergoing this surgery are most appropriate for indirect decompression alone over laminectomy.

Robotic intercostal nerve graft for reversal of thoracic sympathectomy: a large animal feasibility model.

BACKGROUND: A subset of patients who undergo video-assisted thoracoscopic sympathectomy for hyperhydrosis develop post-procedure compensatory sweating that is perceived as more debilitating than their initial complaints. We propose a novel treatment to reverse sympathectomy by implantation of an intercostal nerve graft using the da Vinci robot. METHODS: A robotic swine model was established using single-lung ventilation and four ports. The pleura was incised and a representative segment of sympathetic chain was transected. A nearby intercostal nerve was harvested and sutured to the sympathetic chain using four interrupted 10-0 nylon sutures on the epineurium. RESULTS: The intercostal nerve was an excellent size match and post-procedure necropsy yielded successful anastomoses without apparent complications. CONCLUSIONS: Robotic intercostal nerve grafting for reversal of thoracic sympathectomy is technically feasible. The robotic device allows the principles of neural microsurgery to be maintained and provides a minimally invasive option for reconstruction of the sympathetic chain.

Polymorphism at GSTM1, GSTM3 and GSTT1 gene loci and susceptibility to oral cancer in an Indian population.

This study evaluates the influence of genetic polymorphism at GSTM1, GSTM3 and GSTT1 gene loci on oral cancer risk among Indians habituated to the use of, smokeless tobacco, bidi or cigarette. DNA extracted from white blood cells of 297 cancer patients and 450 healthy controls by the proteinase K phenol-chloroform extraction procedure were analyzed by the polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) analyses. Lifetime tobacco exposure was evaluated as a risk factor in relation to the polymorphism at the GST gene loci using logistic regression analysis. There was no significant difference in the distribution of the GSTM3 and GSTT1 genotypes between oral cancer patients and controls. In contrast, a significant 3-fold increase in risk was seen for patients with the GSTM1 null genotype (age adjusted OR = 3.2, 95% CI 2.4-4.3). The impact of the GSTM1 null genotype on oral cancer risk was also analyzed in separate groups of individuals with different tobacco habits. The odds ratio associated with the GSTM1 null genotype was 3.7 (95% CI 2.0-7.1) in tobacco chewers, 3.7 (5% CI 1.3-7.9) in bidi smokers and 5.7 (95% CI 2.0-16.3) in cigarette smokers. Furthermore, increased lifetime exposure to chewing tobacco appeared to be associated with a 2-fold increase in oral cancer risk in GSTM1 null individuals. The results suggest that the GSTM1 null genotype is a risk factor for development of oral cancer among Indian tobacco habitues.

[Intestinal absorption of D-xylose in children infected with the human immunodeficiency virus]. / Absorção intestinal de D-xilose em crianças infectadas pelo vírus da imunodeficiência humana.

AIM: To evaluate the intestinal absorption in HIV-infected children children 14 months to 14 years and to investigate its relationship to diarrhea, nutritional status, immune dysfunction, classical enteric parasites and Cryptosporidium. METHODS: Intestinal absorption was investigated by measuring serum D-xylose. Fecal samples were investigated for classical pathogens and Cryptosporidium. The sample size was calculated considering a 30% prevalence of altered D-xylose absorption in HIV-infected children with a 5% accuracy. Statistical procedures used were: descriptive measurements, multiple correspondence analysis and logistic regression. RESULTS: D-xylose absorption was altered in only 8 out of 104 (7.7%) and Cryptosporidium was positive in 33 out of 104 (31.73%) HIV-infected children. The multiple correspondence analysis suggested an association between an altered D-xylose test and Cryptosporidium. D-xylose malabsorption was not associated with diarrhea, nutritional status, immune disfunction and classic enteric parasites. CONCLUSIONS: Intestinal malabsorption evaluated through the D-xylose test was an uncommon finding in HIV-infected children. Intestinal dysfunction when present seems to be related to Cryptosporidium, but not to diarrhea, nutritional status, immune disfunction and classic enteric parasites.

Parathyroid hormone and bone metabolism in kidney-transplanted patients.

BACKGROUND: Decreases in bone mass and increased susceptibility to fractures are well-recognized complications in organ transplants. SUBJECTS AND METHODS: We performed a cross-sectional study on 60 patients (40 males, 20 females, mean age 43.2 +/- 1.06, SE range 22 - 70) who underwent kidney transplantation (KTX) 55.6 +/- 4.5 months before. Blood and 24-hour urine samples were analyzed for the main parameters of mineral metabolism, and also for osteocalcin (BGP), bone alkaline phosphatase (b-ALP, urine N-telopeptid (u-NTx) and urine galactosyl-hydroxylysine (u-Ghyl). DEXA scan of the lumbar spine (LS) and proximal femur (PF) and ultrasound determination of the heel (stiffness) was also performed. RESULTS: T-score values for bone density (BD) were 2.14 +/- 0.11 SD's for LS, -2.56 +/- 0.09 for PF and 2.49 +/- 0.15 for stiffness. There were 29 peripheral fractures in 16 patients. The rate of fractures before KTX were 0.0011 per patient/year and 0.0005 after transplantation (p < 0.02). When expressed as number of SD's with respect to normal controls, BGP (1.48 +/- 0.23), b-ALP (0.95 +/- 0.19), u-NTx excretion correlated negatively with BD at the femoral neck (p < 0.02) and trochanter (p < 0.03). Cumulative steroids intake were negatively correlated with b-ALP positively (p < 0.05). Current CsA was positively correlated with b-ALP (p < 0.001). Both cumulative steroid (p < 0.02) and CSA (p < 0.01) intakes were negatively correlated with BD at Wards triangle. CONCLUSIONS: Our data demonstrate an important bone depletion at each stage KTX. PTH plays a major role in the observed increase in bone turnover, exacerbating the negative effects on the bone on immunosuppressive treatment. Glucocorticosteroid therapy is an important risk factor for osteoporosis in this setting also.

Somatosensory evoked potential monitoring in anterior thoracic vertebrectomy.

OBJECT: Spine surgeons have used intraoperative cortical and subcortical somatosensory evoked potential (SSEP) monitoring to detect changes in spinal cord function when intraoperative procedures can be performed to prevent neurological deterioration. However, the reliability of SSEP monitoring as applied to anterior thoracic vertebral body resections has not been rigorously assessed. METHODS: The authors retrospectively reviewed hospital charts and operating room records obtained between August 1993 and December 1998 and found that SSEP monitoring was used in 44 surgical procedures involving an anterior approach for thoracic vertebral body resections. There were no patients in whom SSEP changes did not return to baseline during the surgical procedure. Patients in four cases, despite their stable SSEP recordings throughout the procedure, were noted immediately postoperatively to have experienced significant neurological deterioration. The false-negative rate in SSEP monitoring was 9%. Sensitivity was determined to be 0%. CONCLUSIONS: It is important to recognize high false-negative rates and low sensitivity of SSEP monitoring when it is used to record spinal cord function during anterior approaches for thoracic vertebrectomies. The insensitivity of SSEPs for motor deterioration during anterior thoracic vertebrectomies is likely due to the limitation of SSEPs, which monitor only posterior column function whereas motor paths are conveyed in the anterior and anterolateral spinal cord. The authors believe that SSEPs can not be relied on to detect reversible spinal damage during anterior thoracic vertebrectomies.

Dietary lipid composition modifies intestinal morphology and nutrient transport in young rats.

BACKGROUND: Varying lipid content of the diet of pregnant and nursing dams results in alterations in sugar and lipid uptake into the intestine of their suckling offspring. In this study, we wished to determine whether the same alterations in dietary lipid result in adaptation of intestinal transport in postweaning rats. METHODS: During nursing, the dams were fed the same diet that their offspring were fed for 3 more weeks after weaning. These semipurified diets contained: 1) 15.8% of total fatty acids (w/w) as 18:2n-6 and an n6/n3 ratio of 7.3:1; 2) a diet with 17.6% of total fatty acids as 18:2n-6 and an n6/n3 ratio of 4:1; 3) a diet with 16.2% of total fatty acids as 18:2n-6 and 1.2% arachidonic acid (AA); 4) a diet with 16.8% of total fatty acids at 18:2n-6, 1.2% AA and 0.7% docosahexaenoic acid (DHA); and 5) a diet with 16.0% of total fatty acids as 18:2n-6 and 0.7% as DHA. The in vitro uptake of D-glucose, D-fructose, medium- or long-chain fatty acids and cholesterol was assessed in 6-week-old rats. RESULTS: Feeding AA increased the Vmax for jejunal and ileal uptake of glucose, compared with the high n6/n3 diet. This effect was prevented by adding DHA to the AA diet. The low n6/n3 fatty acid ratio diet decreased uptake of fructose as compared with the high n6/n3 diet, and the increased uptake of fructose with DHA was prevented by adding AA. The incremental change in free energy associated with uptake of medium chain-length fatty acids was lower in the jejunum of animals fed AA plus DHA as compared with the other diet groups. Jejunal uptake of 18:0 was lower for animals fed DHA or AA plus DHA, as compared with AA alone; ileal rate of uptake of long-chain fatty acids was unaffected by diet. CONCLUSIONS: The intestine of young rats modifies its intestinal morphology and adapts its nutrient transport in response to variations in dietary lipids. In postweaning rats, the potentially undesirable effect of one fatty acid on nutrient uptake may be countered by adding a select second fatty acid to the diet.

Early dietary experience influences ontogeny of intestine in response to dietary lipid changes in later life.

This study was undertaken to test the hypothesis that a change in the mother's diet at the time of birth and continued during suckling modifies the intestinal transport of nutrients in the suckling offspring. Pregnant rat dams were fed one of four semisynthetic diets during pregnancy [high or low n-6/n-3 diet or a diet enriched with arachidonic acid (AA) or docosahexaenoic acid (DHA)] and were fed the same diet at the time of birth or switched to another diet. The greatest body weight gain was in the suckling rats (15-16 days of age) fed a low n-6/n-3 diet. Switching from this diet caused weight loss, and the observed weight gain with the low n-6/n-3 diet was prevented by previous exposure of the mother to the high n-6/n-3 diet or the AA- or DHA-containing diet. Although continuous feeding of a high n-6/n-3 diet to the mother during pregnancy and lactation was associated with the lowest in vitro rates of fructose uptake, switching the mother to another diet during lactation did not necessarily correct the low absorption. In contrast, continuous feeding of a high n-6/n-3 diet to the mother during pregnancy and lactation is associated with the highest maximal transport rate of glucose uptake into the jejunum and ileum. Jejunal uptake of fatty acids 12:0, 18:0, 18:3(n-3), and cholesterol was less with the low n-6/n-3 diet compared with the high n-6/n-3 diet, whereas the ileal uptake of 18:0 and 18:3(n-3) was higher with the low n-6/n-3 diet. Thus the ontogeny of the intestine is critically influenced by the mother's diet during gestation as well as during the nursing period. Some of the diet-associated changes in nutrient uptake resulting from the mother's diet during pregnancy could be corrected by dietary interventions introduced after birth.