The influence of microhabitat on the population dynamics of four herbaceous species in a semiarid area of northeastern Brazil / A influência dos microhabitats sobre a dinâmica de populações de quatro espécies herbáceas em uma área semiárida no nordeste do Brasil

Abstract Variation in annual rainfall is considered the most important factor influencing population dynamics in dry environments. However, different factors may control population dynamics in different microhabitats. This study recognizes that microhabitat variation may attenuate the influence of climatic seasonality on the population dynamics of herbaceous species in dry forest (Caatinga) areas of Brazil. We evaluated the influence of three microhabitats (flat, rocky and riparian) on the population dynamics of four herbaceous species (Delilia biflora, Commelina obliqua, Phaseolus peduncularis and Euphorbia heterophylla) in a Caatinga (dry forest) fragment at the Experimental Station of the Agronomic Research Institute of Pernambuco in Brazil, over a period of three years. D. biflora, C. obliqua and P. peduncularis were found in all microhabitats, but they were present at low densities in the riparian microhabitat. There was no record of E. heterophylla in the riparian microhabitat. Population size, mortality rates and natality rates varied over time in each microhabitat. This study indicates that different establishment conditions influenced the population size and occurrence of the four species, and it confirms that microhabitat can attenuate the effect of drought stress on mortality during the dry season, but the strength of this attenuator role may vary with time and species.

Resumo A variação anual na precipitação é considerada o fator mais importante que influencia a dinâmica populacional em ambientes secos. No entanto, diferentes fatores podem controlar a dinâmica populacional em diferentes microhabitats. A hipótese deste estudo é que as variações de microhabitats podem atenuar a influência da sazonalidade climática sobre a dinâmica populacional de espécies herbáceas em uma áreas floresta seca (Caatinga) no Brasil. Então, objetivou-se avaliar a influência de três microhabitats (plano, rochoso e ciliar) sobre a dinâmica das populações de quatro espécies herbáceas (Delilia biflora, Commelina obliqua, Phaseolus peduncularis e Euphorbia heterophylla) em um fragmento de Caatinga da Estação Experimental do Instituto de Pesquisas Agronômicas de Pernambuco, no Brasil, durante um período de três anos. D. biflora, C. obliqua e P. peduncularis foram encontrados em todos os microhabitats, mas elas estavam presentes em baixas densidades no microhabitat ciliar. Não houve registro de E. heterophylla no microhabitat ciliar. O tamanho das populações, as taxas de mortalidade e de natalidade variaram ao longo do tempo em cada microhabitat. Este estudo indica que diferentes as condições de estabelecimento influenciaram o tamanho das populações e a ocorrência das quatro espécies e confirma que microhabitat pode atenuar o efeito do estresse hídrico sobre a mortalidade durante a estação seca, mas a força desse papel atenuador pode variar com o tempo e a espécie considerada.

Effects of propranolol on human postoperative ileus.

BACKGROUND: The sympathetic nervous hyperactivity present in response to surgical stress has been implicated as an important component of the postoperative paralytic ileus. A randomized and prospective study was conducted, evaluating the effects of the preoperative beta-adrenergic blockade with propranolol in schistosomotic patients during the period of postoperative ileus. METHODS: The study compared schistosomotic patients submitted, or not, to beta-adrenergic blockade. Basal cardiac frequency was determined and propranolol was used in a dose of 40 mg twice a day. The dose was adjusted weekly until a minimum decrease of 20% in cardiac frequency was achieved. Three coupled bipolar electrodes were placed in the left colon in both groups, and registration of myoelectric activity of the left colon was made twice a day during the period of postoperative ileus using a system of data collection (DATA Q Series 200). The electric signals were previously amplified, filtered and separated into Electric Control Activity (ECA) and Electric Response Activity (ERA). RESULTS: The dose of propranolol varied from 80 to 160 mg/day. The proportional decrease in basal heart frequency varied from 20 to 33%, with an average of 25.4 +/- 3.9% in the propranolol group, maintaining a mean of 24.3 +/- 3.6% decrease in the postoperative period. Differences on clinical recovery of the postoperative ileus were not found. Significant differences on electromyographic patterns were not observed between the groups, except for the presence of a greater number of short-duration contractions in the second postoperative day in the beta-blocked group. CONCLUSION: The authors suggest that the preoperative beta-adrenergic blockade with propranolol does not determine myoelectric activity changes that could contribute to an earlier resolution of postoperative ileus.

Surgical treatment of schistosomal portal hypertension.

Schistosomiasis mansoni is a widespread parasitic disease in the Brazilian territory that affects over 8 million individuals. Hepatosplenic schistosomiasis is a serious clinical presentation of this disease, associated with splenomegaly, liver fibrosis, and portal hypertension, and is responsible for approximately 7% of schistosomotic patients. The surgical treatment of portal hypertension in schistosomotic patients has distinct features when compared with cirrhotic patients, mostly because hepatic function is preserved in schistosomotic liver disease. Therefore, when attempting to reduce the portal pressure, the surgeon must be aware that the surgery might interfere with hepatic perfusion, and consequently with hepatic function. The aim of this study was to report the results achieved with splenectomy, division of the left gastric vein, devascularization of great gastric curvature, and postoperative endoscopic variceal sclerosis, as a surgical option to esophageal varices in hepatosplenic schistosomiasis. A total of 111 patients were studied, and the following is a list of inclusion criteria: age >16 years, history of gastrointestinal (GI) bleeding, presence of esophageal varices on preoperative endoscopy, hematocrit >22% and prothrombin enzymatic activity >50%, negative viral hepatitis on serologic tests (anti-HBV and anti-HCV), and definition, after liver biopsy, of exclusive schistosomotic liver disease. The following list includes exclusion criteria used: presence of liver disease other than schistosomotic, history of alcohol abuse, and preoperative thrombosis of the portal vein. The rebleeding rate was 14.4% during a mean 30-month follow-up period; portal vein thrombosis was 13.2%, and there was a global mortality of 5.4%. Gastric varices were present in 46.9% of the patients; for those patients, a gastrotomy and running suture of the varices achieved an eradication rate of the varices of 75.6%. The degree of periportal fibrosis was also analyzed. Periportal fibrosis staging revealed that patients with class II or III liver fibrosis had a significant increased risk of recurrent GI bleeding when compared with patients with class I liver fibrosis. Despite the elevation on alanine aminotransferase (ALT) and aspartate aminotransferase (AST), most other liver function tests showed no alteration or were corrected after surgery. We conclude that splenectomy, division of the left gastric vein, devascularization of great gastric curvature, and postoperative endoscopic variceal sclerosis showed good results globally and should be considered as therapeutic options in the treatment of hepatosplenic schistosomiasis.

[Splenectomy plus left gastric vein ligature and devascularization of the great curvature of the stomach in the treatment of hepatosplenic schistosomiasis. Postoperative endoscopic sclerosis is necessary?]. / Esplenectomia com ligadura da veia gástrica esquerda e desvascularização da grande curvatura do estômago no tratamento da esquistossomose hepatoesplênica. E necessária a escleroterapia endoscópica pós-operatória?

OBJECTIVE: With the intention of evaluating the effectiveness and the maintenance of the postoperative endoscopic sclerosis as routine, in association to splenectomy with left gastric vein ligature and devascularization of the great curvature of the stomach, the present study was accomplished. METHOD: Between 1992 and 1998, 131 patient were operated in the General Division of the "Hospital das Clínicas" (Federal University of Pernambuco, Recife, PE, Brazil). The medium follow-up was 30 months. All patients were requested to come back to the clinic for accomplishment of clinical and laboratory control. Of the 111 patients that came back to the clinic, 80 patients had a digestive endoscopy done. Of these 80 patients, 36 followed the recommendation and underwent to a postoperative endoscopic sclerosis program (group 1), while 44 did not accomplish postoperative endoscopic sclerosis (group 2). RESULTS: Regarding the eradication of the esophagus varices, the authors found a statistical difference between the groups (52.7% of the group 1 vs. 18.2% of the group 2). Other analyzed items (mortality, rebleeding rate, thrombosis of the portal vein, gastric varices and degree of periportal fibrosis) statistical relevance was not observed. CONCLUSION: The association of the postoperative endoscopic sclerosis to the splenectomy with left gastric vein ligature and devascularization of the great curvature of the stomach, in the treatment of schistosomotic portal hypertension with digestive hemorrhage antecedent, should be maintained.

Avaliação do tempo de sobrevida pós-operatória em lesão de isquemia normotérmica e reperfusão hepática induzidas em cães / Evaluation of postoperative survival time in normothermic hepatic ischaemia and reperfusion lesion induced in dogs

Prolongamento do tempo de sobrevida em animais de experimentação tem sido requerido para melhor investigação da fisiopatologia e da modulação farmacológica em lesões decorrentes de isquemia e reperfusão hepática. Vinte cães mestiços, pesando 15,25+-1,21Kg, foram distribuídos em dois grupos de investigação: 1. Grupo Teste (n=10) - Os animais foram submetidos a isquemia normotérmica de aproximadamente, 70por cento do fígado, durante 90 minutos, com descompressão venosa esplâncnica translobar, sequida de reperfusão hepática; 2.Grupo controle (n=10)- os cães foram submetidos a operação simulada. O tempo de sobrevida foi analisado estatisticamente através do teste do chi quadrado . Com confiança de 95 por cento, os resultados revelaram que: o índice de sobrevida de 72 horas (30Por cento) verificado no grupo teste foi significativamente inferior aos constatado nos animais do Grupo Controle (100por cento), em igual período. Bem como, observou-se que a causa mais frequente de óbto nos animais do Grupo Teste foi insuficiência hepática diagnosticada clínicamente e com dados da necróspsia, associada a diátese hemorrágica ou peritonite (60por cento) e ocorrida emtre 2 a 96 horas de pós-operatório. No grupo controle, o sangramento digestiavo e deiscência de parede abdominal, ambos associados a peritonite clínica, constituíram causas de óbitos observadas em dois animais, entre o 4§ e o 6§ dia de pós-operatório

Wound infection rates in clean surgery: a potentially misleading risk classification.

OBJECTIVES: To evaluate the incidence of wound infection in inguinal hernioplasties, incisional hernioplasties, splenectomies, and splenectomies performed in patients with hepatosplenic schistosomiasis, and to examine the relationship of surgical wound infection to antibiotic use, patient age, length of stay in the hospital prior to surgery, and the duration of the operation. DESIGN: Retrospective surveillance study. RESULTS: One thousand five hundred forty-two clean operations were analyzed. Comparing response (wound infection) and explanatory variables (age, length of hospital stay, duration of surgery, antibiotics, and surgery type), we found that age, use of antibiotics, and type of surgery were statistically significant, while length of hospital stay and duration of surgery were not significant. CONCLUSIONS: From these results, we can predict that the probability of wound infection in surgical patients considering these significant variables is lower for patients ages 14 to 30 years and higher for patients ages 31 to 60 years and lower for patients with prophylactic antibiotic use (up to 72 hours of use) and higher for patients with prolonged use (more than 72 hours); and lower for patients undergoing inguinal heria, followed in ascending order by nonschistosomotic patients undergoing splenectomy in schistosomotic patients.

Levels and determinants of early neonatal mortality in Natal, northeastern Brazil: results of a surveillance and case-control study.

An institution-based surveillance and nested case-control study was conducted in Natal, Northeastern Brazil to estimate the level and determinants of early neonatal mortality. The early neonatal mortality rate was 25.5 per 1000 live-birth, 75% of early neonatal deaths were premature low birthweight infants, and the mortality rates were 591 and 318 per 1000 respectively, for preterm small for gestational age (PT-SGA) and preterm appropriate for gestational age (PT-AGA) infants. Mortality was 50 per 1000 for term low birthweight, and 8.6 for term normal birthweight AGA infants. In addition to prematurity and low birthweight, the main risk factors associated with early neonatal death were maternal smoking, complications during pregnancy or intrapartum, and inadequate antenatal care. The associations were weaker for prepregnancy factors such as single marital status or low maternal body weight, and no significant associations were observed with socioeconomic status. These findings suggest that in this population, efforts to reduce early neonatal death should focus on improved maternal care and the prevention of prematurity.

PIP: To facilitate health service planning, a surveillance and case-control study were conducted of births in 3 hospitals and 2 maternity clinics in the city of Natal in northeastern Brazil. The surveillance study revealed 285 early neonatal deaths among the 111,171 singleton live births recorded in the study institutions from September 1984-February 1986, for a rate of 25.5/1000. 75% of these early neonatal deaths involved premature infants. The mortality rates were 591/1000 for preterm small-for-gestational age infants and 318/1000 for preterm appropriate-for-gestational age infants, while this rate was 50/1000 for term low-birthweight infants and only 8.6/1000 for term normal birthweights infants. The case-control study indicated that the maternal risk factors of body weight under 50 kg and single parent status significantly increased the likelihood of early neonatal mortality, while maternal age, parity, prior reproductive loss, and socioeconomic status did not have a significant effect on this outcome. Pregnancy-related factors that substantially increased the risk of early neonatal death included smoking, bleeding during the first or second trimester, toxemia, less than 5 prenatal care visits, and congenital malformations. These pregnancy-related risks exerted a more substantial effect than maternal characteristics, suggesting the feasibility of a strategy focused on preventing preterm births through prenatal care rather than a high-risk approach of screening women prior to pregnancy.

Complete acute occlusion of the portal vein in dogs: I. a study based on hemodynamic and hematologic data aimed at its application in liver transplantation

Como etapa inicial de um plano de pesquisa sobre avaliacao de medidas descompressivas portosistemicas, comumente utilizadas em transplante hepatico experimental, foram estudados 20 caes mesticos, adultos, de ambos os sexos e com peso corporal de 15,2ñ1,7kg. Em dez caes praticou-se oclusao total e aguda da veia porta por um periodo de 2 horas (grupo oclusao portal). Em dez outros desses animais procedeu-se a operacao simulada (grupo controle). Foram investigados de modo sistematico dados hemodinamicos de pressao arterial (PA), pressao venosa central (PVC) e pressao portal (PP), assim como dados hematologicos de concentracao de hemoglobina (cHb) nos animais dos grupos estudados...

A case-control study of stillbirths in northeast Brazil.

An institution based case-control study to determine risk factors for stillbirths was conducted in the city of Natal, NE Brazil, where 90% of deliveries take place in health facilities. Two hundred thirty-four singleton stillborn cases were compared to 2555 liveborn singleton control infants of normal birth-weight and gestational age. Information was obtained by postnatal interview and anthropometry, and review of medical records. Univariate analyses revealed a large number of potential risk factors, but after adjustment by logistic regression only six factors remained significantly associated with stillbirth. These were low maternal weight, less than or equal to 50 kg and a history of pregnancy loss, both with odds ratios (OR) of 1.8, inadequate prenatal care defined as less than five visits (OR = 1.9), gestational complications (OR = 14.2), intrapartum complications (OR = 2.0), and congenital malformations (OR = 8.7). There was also an increased risk of stillbirth among older mothers who smoked (OR = 1.4), and evidence of an interaction between smoking and complications of pregnancy. From the public health perspective, the most important factors amenable to intervention were inadequate prenatal care and antenatal or intrapartum complications which were associated with substantial attributable risks (23.8%, 35.2%, and 10.2%, respectively). Thus, in this population, future reductions of the high stillbirth rate (27.2 per 1000 births) will largely depend on the coverage, utilization, and quality of antenatal and intrapartum care.

Determinants of preterm delivery and intrauterine growth retardation in north-east Brazil.

A case-control study was conducted in Natal, north-east Brazil to determine the risk factors for low birthweight (LBW). Cases were 429 preterm and 422 intrauterine growth retarded (IUGR) singleton infants. Controls were 2555 infants of normal birthweight and gestational age. The prevalence of LBW was 10% (5.1% preterm and 4.9% IUGR). Logistic regression was used to estimate the adjusted odds ratios of LBW, and attributable risk per cent (AR%) was used to estimate the proportion of LBW that might be prevented. The preventable determinants of preterm delivery were births to women less than 20, (AR = 7.1%), low maternal weight less than 50 kg (AR = 20.5%), smoking during pregnancy (AR = 14.6%) and infrequent antenatal visits (AR = 28.1%). Other important determinants of preterm delivery were prior LBW births, gestational illness and vaginal bleeding. The main preventable causes of IUGR were low maternal weight (AR = 17.8%), low maternal education (AR = 11.6%), smoking (AR = 14.8%), and inadequate antenatal care (AR = 11.6%). Other risk factors for IUGR include primiparity, prior LBW births, and illness during gestation. In this population, the focus of short-term preventive programme should be improvement in maternal nutrition, cessation of smoking, reduction of births to women under 20, and improved antenatal care.

Interpregnancy interval and low birth weight: findings from a case-control study.

In a case-control study in Natal, northeast Brazil, conducted between September 1984 and February 1986, 303 cases of intrauterine growth retardation and 282 cases of preterm delivery were compared with 1,710 normal controls to ascertain the effects of the preceding birth-to-conception interval on pregnancy outcome. The risk of intrauterine growth retardation associated with interpregnancy intervals of six months or less was 1.38 (95% confidence interval (CI): 1.02-1.86) after adjustment for maternal age, education, smoking, and prior fetal loss or low birth weight. When maternal postpartum body weight was introduced into the logistic model, the risk of intrauterine growth retardation decreased slightly to 1.25 and was no longer significant (95% CI: 0.91-1.72). Short interpregnancy intervals (six months or less) were more frequently observed in women with postpartum body weight of less than 45 kg (31.1%) than in women weighing 50 kg or more (18.9%), which might suggest that the effect of short intervals on the risk of intrauterine growth retardation is mediated through maternal nutritional status. No association was found between birth-to-conception intervals and preterm delivery.

The control of infection in general surgery: a four-year prospective study in Brazil.

On January 1, 1977 a prospective study of the control of infection was initiated in the Division of General Surgery of the Federal University of Pernambuco and continues to the present day. The results of the first four years of this study are assessed in this paper. In the period from January 1, 1977 to December 31, 1980 1,636 patients were submitted to surgery, whose operations were classified as clean, clean-contaminated, contaminated and dirty. The number of infections was studied in relation to the type of operation. Other parameters studied included etiology, bacterial sensitivity, infection related to the six surgical groups functioning in the division and to the indication for elective or emergency surgery, respiratory infection, respiratory infection related to the anesthetist who administered the general anesthesia and wound infection in relation to the surgeon who performed the operation. The overall mortality was 2.64% and the percentage of necropsies carried out was 72%. Among the fatalities, sepsis was the predominant cause of death, accounting for 41% of the cases. The authors conclude that the control of infection is fundamental to the education of the medical and paramedical community and is to be regarded as a quality control of the service provided by the division of surgery. It should also be extended to the outpatient department and be accompanied by necropsy on the majority of the patients who fail to survive the operation.

The control of postoperative infection in general surgery.

The results of a prospective study of infection control carried out in the Division of Abdominal Surgery of the Federal University of Pernambuco over a two year period are presented. A total of 760 patients operated on by the various teams of the Division were studied and rates of wound, respiratory and urinary infection were analyzed together with their relationship to the types of surgery performed. The etiology and antibiotic sensitivity of the main etiologic agents are also presented, plus a comparison of the results obtained with data found in the literature.

Deteccao de alto risco obstetrico. Avaliacao de um modelo para niveis de atencao primaria. / Detection of high obstetrical risk. Evaluation of a model for primary care level

Um modelo simplificado para deteccao de risco obstetrico foi testado no periodo de 1 de janeiro a 31 de dezembro de 1978 na Unidade Integrada de Saude de Sobradinho, pelo Setor de Obstetricia e Ginecologia da Universidade de Brasilia. Em 1980 procedeu-se a avaliacao utilizando uma amostragem de 500 casos selecionados aleatoriamente dentre as pacientes internadas no Hospital para atendimento obstetrico no ano de 1978. As variaveis de risco foram dicotomizadas pelo criterio de risco estatistico e risco por patologia. Na avaliacao, estas variaveis foram correlacionadas com os resultados desfavoraveis daquela gravidez. A sensibilidade de 77,4% e a especificidade de 79% foram julgadas muito boas. As variaveis estatisticas apontaram o risco com maior frequencia que as variaveis por patologia. Os autores comentam os resultados e consideram o modelo util para uso em niveis de atencao primaria a saude materno-infantil pela sua simplicidade e baixo custo

Regeneracao hepatica pos-hepatectomia parcial em ratos com fibrose esquistossomotica. / Hepatic regeneration after partial hepatectomy in rats with schistosomotic fibrosis

A regeneracao hepatica pos-hepatectomia parcial em ratos albinos com fibrose esquistossomotica foi estudada atraves da contagem de figuras de mitose, hepatocitos binucleados e cariometria dos hepatocitos em 39 ratos albinos distribuidos em dois grupos: A - 23 ratos dois machos e duas femeas infectados no 3o. mes, e submetidos a hepatectomia parcial no 13o. mes e avaliada a regeneracao 48 horas apos a hepatectomia parcial; B - 16 ratos sete machos e nove femeas sem infeccao operados e avaliada a regeneracao nas mesmas condicoes do grupo A. Os resultados obtidos mostram com uma confianca de 5% que ocorreu regeneracao hepatico pos-hepatectomia parcial de ratos com fibrose hepatica esquistossomotica de forma semelhante aos ratos normais

Advanced megaesophagus with recurrent dysphagia following initial surgical treatment.

The results of the surgical treatment of twenty patients with advanced megaesophagus who had undergone previous treatment are presented. After the previous operation, the asymptomatic period was less than five years in mot cases; symptoms included dysphagia (100%), regurgitation (65%), heartburn (50%), pain (45%), excess saliva (20%) and palpitations (10%). The definitive treatment was cervico-abdominal esophagectomy (45%), distal esophagectomy (20%), Thal-Hatafuku's operation (15%) and miscellaneous (15%). In our experience, the best procedures are cervico-abdominal esophagectomy and Thal-Hatafuku's operation.

Infeccao pos-operatoria na esquistossomose hepatoesplencia. / Postoperative infection in hepatosplenic schistosomiasis

Os autores estudaram 1.339 pacientes submetidos a cirurgias limpas, limpas com contaminacao, contaminadas e infectadas. Entre estes pacientes, estudaram separadamente pacientes com hipertensao portal esquistossomatica para analise comparativa com outras patologias, submetidas a cirurgias equivalentes. Os autores concluiram que pacientes com hipertensao portal esquistossomatica apresentam um risco de infeccao significativamente maior que outros pacientes

Acido ascorbico na esquistossomose mansonica na vigencia ou nao de episodio de hemorragia digestiva. / Ascorbic acid in schistosomiasis mansoni with and without gastrointestinal haemorrhage

Estudo das variacoes dos niveis leucocitarios e plasmaticos de acido ascorbico, pelo metodo de Denson e Bowers, em 20 individuos normais (Grupo I) e em 36 pacientes esquistossomoticos na forma hapato-esplenica sem e com hemorragia digestiva (Grupos II e III, com 18 pacientes cada). Os resultados foram submetidos a uma analise estatistica (t de student) com uma probabilidade de confianca de 95%.Obteve resultados que nao demonstraram diferenca significativa entre os valores do acido ascorbico nos leucocitos dos Grupos I, II e III e observou uma diminuicao significante das concentracoes plasmaticas deste acido no Grupo III, quando comparadas com as dos Grupos I e II