Low flow veno-venous ECMO: an experimental study

Clinical use of extracorporeal membrane oxygenation (ECMO) and carbon dioxide removal (ECCO 2R) have become well established techniques for the treatment of severe respiratory failure; however they require full cardiopulmonary bypass, representing major procedures with high morbidity. We theorized the possibility of an efficient low flow veno-venous extracorporeal membrane gas exchange method. Four mongrel 12 kg dogs were submitted to veno-venous extracorporeal membrane gas exchange via a jugular dialysis catheter using a low flow (10 ml/min) roller pump and a membrane oxygenator for a period of four hours. Respiratory rate was set at 4 breaths/min with a FiO 2 of 21% and ventilatory dead space was increased. Adequate gas exchange was obtained (pO 2139, pCO 224, Sat 99.4%), without major hemodynamic changes or hematuria. Our results demonstrate the feasibility of a low flow, less aggressive system. Further research should be considered.     

Validation of therapeutic test in the diagnosis and treatment of Kala-Azar in children

The author studied the value of therapeutic test for the diagnosis and treatment of kala-azar in children by comparing two groups of patients. The identification of Leishmania donovani in smears of bone marrow confirmed the diagnosis in all fifty seven patients of the control group. In another group with sixteen children, the diagnosis was based on the successful response to the treatment with meglumine antimonate. In none of the patients of the second group the protozoa was identified and the decision to give the specific treatment was based on epidemiological, clinical, biochemical and hematological criteria for the disease. Statistical analysis was performed by Student t test to compare clinical, biochemical and hematological variables between the groups. None of the differences between the groups was statistically significant, suggesting that the therapeutic test was valid, and all patients who received treatment had kala-azar.     

Physician training, university hospitals, and the Unified Health System in Brazil

There are 80 medical schools in Brazil, of which 14 were selected for this study based on their regional distribution and representative characteristics. A survey in 1995 showed a heavy concentration (86%) of in-house practical training in major university hospitals. Only 14% of the hands-on training of students occurred in primary health or community-based clinics or other services related to the nationwide Unified Health System (SUS). University hospitals have been organized according to the specialized ward model, with extensive fragmentation of health care. This article makes several proposals for improving medical training. Changes in medical care are considered crucial to improvement of physician training. Reforms in medical care in such hospitals would be more important than reformulating the medical school itself. A move towards other health care services is recommended; more time devoted to teaching in primary health care systems and other extramural services is crucial for achieving better physician responsibility and competence.     

Laparoscopic management of benign solid and cystic lesions of the liver

OBJECTIVE: The authors present their experience in the laparoscopic management of benign liver disease. The aim of the study is to analyze technical feasibility and evaluate immediate and long-term outcome. SUMMARY BACKGROUND DATA: Indications for the laparoscopic management of varied abdominal conditions have evolved. Although the minimally invasive treatment of liver cysts has been reported, the laparoscopic approach to other liver lesions remains undefined. METHODS: Between September 1990 and October 1997, 43 patients underwent laparoscopic liver surgery. There were two groups of benign lesions: cysts (n = 31) and solid tumors (n = 12). Indications were solitary giant liver cysts (n = 16), polycystic liver disease (n = 9), hydatid cyst (n = 6), focal nodular hyperplasia (n = 3), and adenoma (n = 9). Only solid tumors, hydatid cysts, and patients with polycystic disease and large dominant cysts located in anterior liver segments were included. All giant solitary liver cysts were considered for laparoscopy. Patients with cholangitis, cirrhosis, and significant cardiac disease were excluded. Data were collected prospectively. RESULTS: The procedures were completed laparoscopically in 40 patients. Median size was 4 cm for solid nodules and 14 cm for solitary liver cysts. Conversion occurred in three patients (7%), for bleeding (n = 2) and impingement of a solid tumor on the inferior vena cava (n = 1). The median operative time was 179 minutes. All solitary liver cysts were fenestrated in less than 1 hour. There were no deaths. Complications occurred in 6 cases (14.1%). Two hemorrhagic and two infectious complications were noted after management of hydatid cysts. There were no complications after resection of solid tumors. Three patients received transfusions (7%). The median length of stay was 4.7 days. Median follow-up was 30 months. There was no recurrence of solitary liver or hydatid cysts. One patient with polycystic disease had symptomatic recurrent cysts at 6 months requiring laparotomy. CONCLUSION: Laparoscopic liver surgery can be accomplished safely in selected patients with small benign solid tumors located in the anterior liver segments and giant solitary cysts. The laparoscopic management of polycystic liver disease should be reserved for patients with a limited number of large, anteriorly located cysts. Hydatid disease is best treated through an open approach.     

The extent of Barrett's esophagus depends on the status of the lower esophageal sphincter and the degree of esophageal acid exposure

OBJECTIVE: The purpose of this study was to assess whether the extent of intestinal metaplasia is related to the severity of the gastroesophageal reflux disease. METHODS: A total of 556 consecutive patients with symptoms suggestive of foregut disease had upper gastrointestinal endoscopy with extensive biopsies from the gastroesophageal junction and the esophagus. All patients had esophageal motility and 24-hour pH monitoring. In 411 patients, cardiac-type mucosa was identified; in 147 patients, the cardiac-type mucosa showed intestinal metaplasia. They were divided into 3 groups based on the extent of intestinal metaplasia commonly seen clinically: long segments (>3 cm), short segments (<3 cm), and limited to the gastroesophageal junction. The duration of symptoms, the status of the lower esophageal sphincter, the degree of esophageal acid exposure, and the time to clear a reflux episode were assessed in each group. RESULTS: The presence of intestinal metaplasia in cardiac-type mucosa was associated with the hallmarks of gastroesophageal reflux disease. The extent of intestinal metaplasia correlated strongly with the degree of esophageal acid exposure (r = 0.711; P <.001) and inversely with the lower esophageal sphincter pressure (r = 0.351; P <.001) and length (r = 0. 259; P =.002). Patients with a long segment of intestinal metaplasia (>3 cm) had longer duration of symptoms (16 years) than those patients with a segment of intestinal metaplasia less than 3 cm (10 years; P =.048) or those patients with intestinal metaplasia limited to the gastroesophageal junction (10 years; P =.01). CONCLUSION: The extent of intestinal metaplasia, that is, Barrett's esophagus, is related to the status of the lower esophageal sphincter and the degree of esophageal acid exposure.     

Eryngium spp. (Umbelliferae) as phytotelmata and their Culex (Culex) inhabitants in temperate Argentina

The host-plant fidelity, seasonality, and population dynamics of 3 species of Culex (Culex) were examined from monthly samples of mosquito immatures extracted from the leaf axils of Eryngium pandanifolium and Eryngium cabrerae growing sympatrically in the Punta Lara region of Buenos Aires Province, Argentina. Culex hepperi was collected only from E. pandanifolium, and abundance peaks of its larvae and pupae were asynchronous in forest and field habitats. However, the proportion of plants positive for Cx. hepperi, as well as larval densities and developmental success, did not differ between forest and field. Culex renatoi was collected only from E. cabrerae in the field habitat. The monthly numbers of Cx. hepperi and Cx. renatoi were not significantly correlated with the proportion of their host plants that held water. The stage-specific distributions of Cx. hepperi and C. renatoi numbers were highly skewed towards 1st instars and did not differ between species or, for Cx. hepperi, between forest and field habitats. Culex castroi was collected regularly from the axils of both species of Eryngium, but usually in lesser numbers than either Cx. hepperi or Cx. renatoi. Association analyses indicated significant positive associations between Cx. castroi and the other 2 culicine species in host plants. Culex renatoi occurred preferentially in small E. cabrerae, but Cx. castroi did not discriminate plants based on their size. These 3 species of Culex are known only from Eryngium spp. phytotelmata. We suggest that their host-plant specificity is maintained by oviposition preferences, which are more highly selective for Cx. hepperi or Cx. renatoi than for Cx. castroi.     

Situational factors associated with AIDS risk behavior lapses and coping strategies used by gay men who successfully avoid lapses

While most gay men have reduced behavior practices at high risk for HIV infection, there is growing evidence that many also lapse to unsafe sex. This study examined situational factors related to risk behavior lapses as well as coping strategies used by men who successfully resist lapse urges. A convenience sample of 470 men patronizing gay bars or attending social organization meetings in four cities was surveyed. Forty-five percent of men were classified as "lapsers" (those who had had unprotected anal intercourse in the previous 6 months) and 24% were classified as "resisters" (those who successfully resisted urges to engage in this behavior). All provided information concerning the importance of factors related to the most recent occurrence of either unsafe sex or resisting unsafe urges. Most episodes of unsafe sex occurred outside monogamous relationships and with partners of unknown HIV serostatus, although simply inquiring about partner serostatus was relatively common. Lapsers rated affectionate feelings and wishing to please a partner as well as spontaneity of unsafe sex as the most important situational factors surrounding high-risk behavior. Resisters of unsafe sex urges reported active cognitive self-guidance, experience in safe sex, and recall of both AIDS fears and safety benefits as their most important coping strategies. Gay men who continue high-risk behavior may be overrelying on partner reports of negative serostatus. Lapse prevention approaches tailored to situations that create increased risk vulnerability must be developed. Teaching skills already used by men who successfully resist unsafe sex urges might be one approach.     

Attempts to culturing triatominae in the laboratory using "in vitro" feeding]

In order to simplify breeding of triatominae in the laboratory, for performing xenodiagnosis and other biologic studies, we tried to feed the insects "in vitro" with citrated or defibrinated blood from commercially abated chicken. Two types of efficacy observations were carried out with Triatoma infestans: a) analysis of the chaining of successive nymphal stages, viability of satisfactory matching, fertile oviposition and adequate reproduction; b) assessment of viability and infectivity of Trypanosoma cruzi in the insects. As a conclusion, it became evident that, despite operational easiness, the objectives were not achieved, since the classical procedure used as the control, was always superior.     

Veratridine modifies the TTX-resistant Na channels in rat vagal afferent neurons

A number of neurotoxins from venoms of invertebrates and plants are ligands for voltage-gated Na⁺ channels and are useful tools for studying Na⁺ channel function and structure. Using whole-cell recordings from vagal afferent nodose neurons, we studied neurotoxins that target Na⁺ channels. We asked whether Ts3 (an α-scorpion toxin) and/or veratridine (a lipid-soluble toxin), could modify the TTX-resistant Na⁺ current generated by vagal afferent nodose neurons. Nodose TTX-resistant current was not affected by Ts3, whereas Ts3 slowed inactivation of the current generated by TTX-sensitive current component. We found that veratridine inhibited the TTX-resistant Na⁺ currents on rat nodose neurons. Interestingly, veratridine-modified Na⁺ channels developed a persistent current that accounted for the large tail current observed. We propose that veratridine modifies TTX-resistant Na⁺ channels through a mechanism distinct from its actions on other voltage-gated Na⁺ channels.     

Preoperative uracil, tegafur, and concomitant radiotherapy in operable rectal cancer: a phase II multicenter study with 3 years' follow-Up.

PURPOSE: To assess tolerance and efficacy of preoperative treatment with uracil/tegafur and radiotherapy (RT) followed by surgery and postoperative flurouracil (FU)/leucovorin (LV) in patients with rectal cancer. PATIENTS AND METHODS: Patients (n = 94) with potentially resectable tumors, ultrasound at stages T2N+ (n = 4), T3 (n = 77), T4 (n = 13) were treated with UFT (400 mg/m2/d, 5 days a week for 5 weeks) and concomitant RT to the pelvis (45 Gy; 1.8 Gy/d over 5 weeks). Patients underwent surgery 5 to 6 weeks later followed by four cycles of FU/LV. Primary end points included downstaging, pathologic responses, and sphincter-preserving surgery. Secondary end points were recurrence-free survival and overall survival. RESULTS: All patients received the full RT dose. Fifteen patients (16%) needed UFT dose reduction. Preoperative G3+ toxicities included diarrhea (14%), leukopenia (1%), thrombocytopenia (1%), and nausea (4%). The downstaging rate was 54%, pathologic complete response (pCR) was 9% and, in an additional 23%, there were only residual microscopic foci. When cellular viability criteria were taken into account, the pCR was 15%. From 43 patients with abdominoperineal resection indication, 11 (25%) had sphincter-preserving surgery performed. Postoperative scheduled chemotherapy dose was not administered to 24% of patients because of G3+ toxicity (diarrhea, 8%; mucositis, 9%; and leukopenia, 7%). Patients with downstaging had significantly higher survival and recurrence-free survival rates than those without. At 3 years, actuarial patterns of failure were pelvic, 5% and distant, 11%. OS was 75%. CONCLUSION: UFT combined with RT is safe and effective. In resectable rectal cancer, if preoperative treatment is considered, this approach can be an option.