Transitions and transversions in Ki-ras gene in colorectal cancers in Mexican patients

AIMS & BACKGROUND: An important increase in the incidence of colorectal cancers has been detected in the last 15 years in Mexico. This fact has been attributed to several causes, including the change in diet acquired from industrialized countries. Various groups have studied the mutational pattern of oncogenes, including Ki-ras gene, in colorectal cancers from different human populations. The aim of this work was to study the prevalence of mutations at codons 12, 13 and 61 of the Ki-ras gene in 37 colorectal tumors from Mexican patients and to correlate them with clinical data. METHODS: Point mutations were studied in 37 colorectal cancers at codons 12 and 13 of the Ki-ras gene, using PCR followed by RFLP. We also performed PCR-SSCP to identify mutations at codon 61. We confirmed mutations by sequence analysis in all the altered codons. RESULTS: Our results indicated that 24.3% of the tumors presented mutations at codon 12, 5.4% at codon 13, and 2.7% at codon 61 of the Ki-ras gene. We found that 75% of these mutations were transitions and 25% transversions. The overall results indicated that the frequency of Ki-ras mutations in colorectal cancers in a sample of a Mexican population (Mexico City) was 32.4%, which is similar to that reported in other populations. We did not find a correlation between the Ki-ras mutations and gender, location of the tumor, or Dukes' stage, but survival of the patient without recurrence was statistically significant. CONCLUSIONS: The study of colorectal cancer indicated that in a Mexican population Ki-ras mutations were present in tumors of patients who survived without tumor recurrence. Most of them were transitions in the first and second base of codon 12.     

RBC transfusion requirements after allogeneic marrow transplantation: impact of the before-transplant Hb level on transfusion and early survival

BACKGROUND: Most patients undergoing allogeneic marrow transplantation (alloBMT) require transfusions of RBCs. A retrospective analysis was performed to evaluate the utilization and risk factors for RBC transfusions including age and sex of recipient, HLA matching between donor and recipient, disease status at time of BMT, the occurrence of GVHD, ABO blood group compatibility, the source of progenitor cells and the Hb level before BMT (PT-Hb). STUDY DESIGN AND METHODS: Data from 519 consecutive patients receiving transplants between January 1995 and March 2000 were reviewed. The number of RBC transfusions was determined for the following periods: 0 to 60, 61 to 120, and 121 to 180 days after BMT. RESULTS: The transfusion requirements were greatest during the first 60 days after BMT and decreased with time. The total number of units transfused to this cohort of patients was 5398, of which 3505 units were utilized within the first 2 months. The mean number +/- SD of units transfused per patient from 0 to 60 days was 6.8 +/- 6.4; 61 to 120 days, 3.2 +/- 5.5; and 121 to 180 days, 2.0 +/- 4.6. An increased transfusion requirement was associated with lower PT-Hb, major ABO mismatch between donor and recipient, BMT in patients with more advanced disease, use of unrelated donors, older age, and female sex by Spearman's correlation analysis. The source of progenitor cells and the development of GVHD did not influence transfusion requirements. Increased mortality during the 6-month period after transplant was associated with lower PT-Hb, use of unrelated donors, advanced disease status at BMT, and sex by Cox regression analysis. In a multivariate model, PT-Hb remained significant when controlling for the other risk factors. CONCLUSION: The PT-Hb was identified as an independent risk factor for RBC transfusions during alloBMT. As well, a lower PT-Hb was found to be an independent risk factor for increased mortality during the 6-month study period.     

Knowledge of preventive child oral healthcare among expectant mothers in Port Harcourt,Nigeria

This study was carried out to assess the perception of preventive oral care in children among expecting mothers at the antenatal clinic of University of Port Harcourt Teaching Hospital, Nigeria. Women who already had one or more children were selected; participants were drawn from among them by consent and a structured questionnaire was administered. Information obtained included sociodemographic information (age, educational level, employment status, and the parity of the women) and participants' perception of child dental care. Data collection spanned a period of four weeks. Three hundred and eighty two respondents participated and they had a mean age of 30.6 (±4.3 SD) years. The majority of the participants were 26–35 years old (76%) and were primiparous (49.5%) with tertiary education (67%). Toothache was their reported reason for a child's first visit to the dentist (47.4%) while routine dental check-up accounted for (42.7%). A third (35.3%) of the participants agreed that tooth cleaning should begin as soon as the first tooth erupts; 20.7% opined that soft toothbrush and toothpaste are choice materials for cleaning. There were statistically significant associations between parity and (i) child's visit to the dental clinic (p = 0.00); and (ii) the material used in cleaning the baby's teeth (p = 0.00). Also, educational status and knowledge of routine dental check-ups were significantly associated (p = 0.04). The perceptions of dental visits, cleaning of teeth, and commencement of unassisted tooth brushing in children were poor. Pediatric oral health education should be incorporated into ante- and post-natal clinics.     

Capillary electrophoresis analysis of the degradation of the aspartyl tripeptide Phe-Asp-GlyOH at pH 2.0 and 7.4 under forced conditions

The degradation of the tripeptide l-Phe-α-l-Asp-GlyOH was studied at 80 °C and pH 2.0 and 7.4 by capillary electrophoresis. Separation of most known as well as unknown degradation products was achieved in a 50 mM sodium phosphate buffer, pH 3.0. The diastereomers l-Phe-α-l-Asp-GlyOH/l-Phe-α-d-Asp-GlyOH could only be separated upon addition of 16 mg/ml carboxymethyl-β-cyclodextrin and 5% acetonitrile to the background electrolyte. Compound identification was performed by capillary electrophoresis-electrospray ionization-mass spectrometry. In addition to Asp isomerization and epimerization products as well as hydrolysis products four diketopiperazine derivatives were identified. Moreover, two degradation products were observed containing the amino acids Asp, Gly and Phe but the unequivocal assignment could not be accomplished based on the mass spectra. Following validation with regard to linearity, range, limit of detection, limit of quantitation and precision the assay was applied to the analysis of the incubation solutions. While peptide backbone hydrolysis dominated at pH 2.0, isomerization and enantiomerization yielding β-Asp and d-Asp peptides as well as cyclization to diketopiperazine derivatives were observed at pH 7.4. The diketopiperazines were the dominant reaction products amounting to about 85% of the compounds detected after the maximal incubation time of 240 h. A kinetic model was used to fit the concentration versus time data.     

Second‐Trimester Genetic Sonography After First‐Trimester Combined Screening for Trisomy 21

Objective. The purpose of this study was to evaluate the trisomy 21 screening performance of the first‐trimester combined test followed by second‐trimester genetic sonography. Methods. This retrospective cohort study included all women with singleton pregnancies undergoing combined screening followed by genetic sonography at 17 to 21 weeks from January 1, 2005, to January 31, 2008. Combined test trisomy 21 risks were multiplied by positive or negative likelihood ratios based on the second‐trimester sonographic findings to determine the final trisomy 21 risk. Sonography was evaluated as the second part of (1) a stepwise sequential test applied to combined screen‐negative pregnancies and (2) an integrated test applied to all combined screen patients regardless of the latter results. A final trisomy 21 risk of 1:270 or higher was considered screen‐positive. Results. A total of 2231 pregnancies underwent combined screening, which detected 7 of 8 Down syndrome cases (87.5%) at a 9.6% screen‐positive rate. A total of 884 of these patients (39.6%), including 2 having fetuses with Down syndrome, had genetic sonography. Combined screening detected 1 of these trisomy 21 fetuses (50%) at a 15.7% screen‐positive rate. Integrated ultrasound‐based aneuploidy screening detected both trisomy 21 cases (100%) at a 22.7% screen‐positive rate, whereas stepwise sequential ultrasound‐based aneuploidy screening also detected both trisomy 21 fetuses (100%) but at a 28.3% screen‐positive rate (P < .0001). Conclusions. Second‐trimester genetic sonography after first‐trimester combined screening may improve trisomy 21 detection at the expense of increasing screen‐positive rates.     

Increased serum levels of soluble Fas in progressive B-CLL

Clinical progression of B-cell chronic lymphocytic leukemia (B-CLL) depends on survival and accumulation of leukemic cells, regulated in part by physical cell contact and soluble molecules. Here we have studied the Fas/FasL system in relation to clinical progression in B-CLL. Serum levels of soluble Fas (sFas) and FasL (sFasL) were determined by ELISA in 43 progressive and 40 non-progressive B-CLL patients and in 21 control individuals. Correlation between sFas serum levels and clinical progression, stage and survival were statistically analyzed. We found high levels of sFas in B-CLL sera correlated with disease progression (p<0.01). In addition, higher sFas levels were found in patients in stages II, III and IV in comparison to patients in stage 0 (p<0.05, p<0.01, p<0.03, respectively). Survival was significantly shorter for patients with > or =6 ng/ml sFas serum levels, although a multivariate analysis did not show sFas to be a significant independent prognostic factor. Fresh B-CLL cells showed only low levels of membrane expression, which were not correlated to sFas levels in serum. In vitro activation of B-CLL cells increased Fas expression, as reported earlier, and induced cells to release sFas into the supernatant. In conclusion, our results indicate that sFas in serum may be a useful parameter for the prediction of clinical progression in B-CLL.     

Spheronization of Small Extrudates Containing κ-Carrageenan

Spheronization of extrudates of around 500 µm diameter needs improvement of the Schlueter spheronizer conditions with regard to moisture content of the extrudates. The extrudates were obtained by a twin-screw extruder and contained κ-carrageenan as pelletization aid. The influences of spheronization speed, residence time, temperature of the spheronizer wall and loading on the responses aspect ratio, pellet size and yield, were studied with a central composite circumscribed design. The Schlueter spheronizer was compared with a Nica spheronizer. Further, additional spheronizer process variables such as temperature of the spheronizer wall and inlet air pressure were also investigated. The results were evaluated in a full factorial (mixed) design. The micropellets in general showed a pellet size between 500 and 700 µm. A twisted-rope movement during the spheronization process was not observed and adhesion to the spheronizer wall resulted in suboptimal micropellets. However, at suitable moisture content, less loading in the spheronizer, higher spheronization speed and longer residence time micropellets with an aspect ratio below 1.1 were obtained. In addition the adhesion to the spheronizer wall was reduced. Spheronizer wall temperature and inlet air pressure were negligible variables. Significant differences between the two spheronizers could not be established. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3776–3787, 2009     

Nonmedical fetal ultrasound: knowledge and opinions of Maine obstetricians and radiologists.

OBJECTIVE: The purpose of this study was to evaluate knowledge and opinions regarding nonmedical fetal ultrasound (NMFU) in obstetricians (OB) and radiologists (R). METHODS: A questionnaire was sent to all Maine fellows of the American College of Obstetricians and Gynecologists practicing obstetrics and members of the Maine Society of Radiology in April 2005. RESULTS: Among OB, 52 (81.2%), 24 (37.5%), 45 (75.0%), and 56 (87.5%) did not know whether the American College of Radiology, American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, or US Food and Drug Administration held positions on NMFU. Among R, 11 (37.9%), 27 (93.1%), 19 (65.5%), and 24 (82.7%) did not know whether the organizations held positions. More R than OB agreed that women might forego medical ultrasound after NMFU (62.1% versus 49.2%; P = .05), whereas more OB than R believed fetal anomalies would go undetected during NMFU (79.4% versus 62.1%; P = .04). OB and R had concerns for false-positive NMFU diagnoses (41.9% and 31.0%), false reassurance by NMFU (76.2% and 62.1%), poor imaging causing anxiety (39.7% and 51.7%), and lack of physician availability to review suspected abnormalities on NMFU (73.0% and 65.5%). Sizable minorities of OB and R believed NMFU providers should be disciplined by licensing boards (33.9% and 44.8%), excluded from society memberships (22.9% and 37.9%), or reported to the Food and Drug Administration (21.3% and 31.0%). CONCLUSIONS: Most Maine OB and R are aware of their own but not each other's professional or regulatory NMFU positions yet practice within these guidelines. Most respondents do not favor sanctioning colleagues performing NMFU.