Optimizing reproducibility evaluation for random amplified polymorphic DNA markers.

The random amplified polymorphic DNA (RAPD) technique is often criticized because it usually shows low levels of repeatability; thus it can generate spurious bands. These problems can be partially overcome by rigid laboratory protocols and by performing repeatability tests. However, because it is expensive and time-consuming to obtain genetic data twice for all individuals, a few randomly chosen individuals are usually selected for a priori repeatability analysis, introducing a potential bias in genetic parameter estimates. We developed a procedure to optimize repeatability analysis based on RAPD data, which was applied to evaluate genetic variability in three local populations of Tibochina papyrus, an endemic Cerrado plant found in elevated rocky fields in Brazil. We used a simulated annealing procedure to select the smallest number of individuals that contain all bands and repeated the analyses only for those bands that were reproduced in these individuals. We compared genetic parameter estimates using HICKORY and POPGENE softwares on an unreduced data set and on data sets in which we eliminated bands based on repeatability of individuals selected by simulated annealing and based on three randomly selected individuals. Genetic parameter estimates were very similar when we used the optimization procedure to reduce the number of bands analyzed, but as expected, selecting only three individuals to evaluate the repeatability of bands produced very different estimates. We conclude that the problems of repeatability attributed to RAPD markers could be due to bias in the selection of loci and primers and not necessarily to the RAPD technique per se.

[Index of the Venezuelan marine microflora: diatoms, dinoflagellates and cocolithophorids]. / Indice de la microflora marina de Venezuela: diatomeas, dinoflagelados y cocolitofóridos.

The marine phytoplankton of Venezuela has been studied on a regular basis since the mid 20th century. However, a species checklist that can be used as a framework for taxonomic studies is lacking. In this paper, an index of the marine microflora of Venezuela is presented for the first time. The index includes only those diatoms (89 centric and 186 pennate species), dinoflagellates (eight naked and 154 thecate species) and coccolithophores (24 species) for which formal diagnosis and illustrations (drawings and/or photographs) have been reported in the scientific literature (journals and/or first degree or master's theses). It is ordered alphabetically according to class, order, family, and species. It includes the author (s) of the taxa.

Laparoscopic colorectal procedures: a multicenter Brazilian experience.

An evaluation of the results of the Brazilian experience in colorectal laparoscopic procedures in a multicenter prospective protocol done by the Brazilian Society of Colo-Proctology is presented. From December 1991 to August 1998, 1,161 patients (583 men and 578 women; mean age, 49.8 years), were operated on laparoscopically. Most of the procedures (40.5%) were for cancer, and the most common procedure was anterior resection (22.5%). The mean operative time was 189 minutes (3.1 hours). There were 42 (3.6%) perioperative complications; visceral injuries were the most common (1.4%). Conversions occurred in 122 (10.5%) cases. There were 148 (12.7%) postoperative complications; wound infections were the most common (5.2%). A liquid diet was started at a mean time of 1.4 days after the operation, and the mean hospitalization period was 6.4 days.

Abdominoperineal resection: laparoscopic versus conventional.

A prospective comparison of laparoscopic (Group 1 = 18 patients) and conventional (Group 2 = 18 patients) abdominoperineal resection in patients with low rectal cancer was carried out. Parameters studied included the length of the procedure, ileus, and hospitalization; the rate of conversion; and the morbidity and mortality rates. The mean (SD) operating time was slightly longer for laparoscopic than for standard surgery: 229 (SD = 56) versus 208 (SD = 45) min; p = 0.47. Moreover, the mean (SD) time to reintroduction of diet of 2.5 (SD = 1.1) days versus 3.8 (SD = 2.1, p < 0.005) and the length of hospital stay of 7.4 (SD = 4.1) days versus 12.9 (SD = 3.9, p < 0.005) were statistically lower in Group 1. Histopathological examination of the resection specimens (length of specimen, lateral margins, and number of lymph nodes retrieved) showed similar results in the two groups. Major complications were few and occurred in a similar proportion in the two groups (4 x 3). The conversion rate was 10% (2/20). One death (5.5%) and two reoperations (11.1%) occurred in group 2. Local recurrence was also similar (1 x 3). There were no port sites or abdominal incisions recurrences. This clinical study indicates that oncologic laparoscopic abdominoperineal resection is not only technically feasible and safe but also provides better postoperative recovery and the same rate of early recurrence and survival as the open technique.

[Pulmonary mechanics in the full-term newborn]. / Mecânica pulmonar no recém-nascido normal.

The objective of this study is evaluate the pulmonary function in full term newborn infants, comparing classic with non-invasive techniques. We describe the pulmonary function laboratory and software developed at Instituto Fernandes Figueira. We studied 10 healthy full-term newborn infants (birthweight 3.260 g + - 460 g) Occlusions were performed at inspiration end and during expiration which allowed us to calculate values for total pulmonary resistance (TPR) and total pulmonary compliance (TPC). Esophageal pressure was measured with a water filled catheter positioned in the lower third of the esophagus, to obtain lung resistance (RL) and compliance (CL). All signals were digitized at 60 Hz into a microcomputer for further analysis. Mean results of our study are: CL= 1.78 + - 0.36 ml/cm H(2)O/kg, TPC= 1.12 + - 0.27 ml/cm H(2)O/kg and TPR= 16 + - 4 cm H(2)O/l/seg/kg. Our values are very similar to the ones in the current literature.

Do hot baths promote anal sphincter relaxation?

Hot perineal baths have been prescribed for the treatment of painful anorectal conditions such as anal fissures and perianal hematomas or for the postoperative care of hemorrhoidectomy. Despite this widely accepted benefit, no studies have been performed to determine whether there is a rational explanation for this procedure. Anorectal manometry was performed in 40 control subjects with no anorectal complaints before and after a hot perineal bath. No significant difference was found between anal pressures at rest or during voluntary contraction before and after the bath. We conclude from this study that no relaxation of anal sphincters can be obtained by hot perineal baths in normal subjects.