Oxygen consumption of rats with broad intestinal resection

The study was performed to investigate possible alterations in oxygen consumption in an animal model with broad intestinal resection. Oxygen consumption and the thermal effect of a short meal were measured in rats subjected to short bowel syndrome. Four groups of rats were used. Group I was the control group, group II was sham operated, group III was submitted to 80% jejunum-ileum resection, and group IV was submitted to 80% jejunum-ileum resection with colon interposition. Ninety days after surgery, oxygen consumption was measured over a period of 6 h with the animals fasted overnight. The thermal effect of feeding was determined in another session of oxygen consumption measurement in animals fasted for 12 h. A 12-kcal meal was then introduced into the animal chamber and oxygen consumption was measured for a further 4 h. No differences in fasting oxygen consumption or in the thermal effect of the meal were detected among the groups studied. It is concluded that short bowel syndrome does not affect the overall energy expenditure of rats.

Influence of acute renal failure on the mononuclear phagocytic system

Several studies show the ability of macrophages to remove particles injected into the bloodstream. This function seems to be increased in the presence of acute renal failure. The objective of the present study was to assess the phagocytic function of the main organs (spleen, liver and lung) of the mononuclear phagocytic system in renal and postrenal failures. Fifteen rats (250-350 g) were divided into three groups (N = 5): group I - control; group II - ligature of both ureters, and group III - bilateral nephrectomy. On the third postoperative day, all animals received an iv injection of 1 ml/kg 99mTc sulfur colloid. Blood samples were collected for the assessment of plasma urea, creatinine, sodium, and potassium concentrations and arterial gasometry. Samples of liver, spleen, lung and blood clots were obtained and radioactivity was measured. Samples of liver, spleen, lung and kidney were prepared for routine histopathological analysis. Plasma urea, creatinine and potassium concentrations in groups II and III were higher than in group I (P<0.05). Plasma sodium concentrations in groups II and III were lower than in group I (P<0.05). Compensated metabolic acidosis was observed in the presence of postrenal failure. Group II animals showed a lower level of radioactivity in the spleen (0.98) and lung (2.63), and a higher level in the liver (105.51) than control. Group III animals showed a lower level of radioactivity in the spleen (11.94) and a higher level in the liver (61.80), lung (11.30) and blood clot (5.13) than control. In groups II and III liver steatosis and bronchopneumonia were observed. Renal and postrenal failures seem to interfere with blood clearance by the mononuclear phagocytic system.

Effect of race, genetic population structure, and genetic models in two-locus association studies: clustering of functional renin-angiotensin system gene variants in hypertension association studies

Previous genetic association studies have overlooked the potential for biased results when analyzing different population structures in ethnically diverse populations. The purpose of the present study was to quantify this bias in two-locus association studies conducted on an admixtured urban population. We studied the genetic structure distribution of angiotensin-converting enzyme insertion/deletion (ACE I/D) and angiotensinogen methionine/threonine (M/T) polymorphisms in 382 subjects from three subgroups in a highly admixtured urban population. Group I included 150 white subjects; group II, 142 mulatto subjects, and group III, 90 black subjects. We conducted sample size simulation studies using these data in different genetic models of gene action and interaction and used genetic distance calculation algorithms to help determine the population structure for the studied loci. Our results showed a statistically different population structure distribution of both ACE I/D (P = 0.02, OR = 1.56, 95% CI = 1.05-2.33 for the D allele, white versus black subgroup) and angiotensinogen M/T polymorphism (P = 0.007, OR = 1.71, 95% CI = 1.14-2.58 for the T allele, white versus black subgroup). Different sample sizes are predicted to be determinant of the power to detect a given genotypic association with a particular phenotype when conducting two-locus association studies in admixtured populations. In addition, the postulated genetic model is also a major determinant of the power to detect any association in a given sample size. The present simulation study helped to demonstrate the complex interrelation among ethnicity, power of the association, and the postulated genetic model of action of a particular allele in the context of clustering studies. This information is essential for the correct planning and interpretation of future association studies conducted on this population.

Effect of antibodies to intercellular adhesion molecule type 1 on the protection of distant organs during reperfusion syndrome in rats

We investigated kidney and lung alterations caused by intercellular adhesion molecule type 1 (ICAM-1) blockade after ischemia and reperfusion of hind limb skeletal muscles. Rats were submitted to ligature of the infrarenal aorta for 6 h. The animals were randomized into three groups of 6 rats each: group I, sacrificed after ischemia; group II, reperfusion for 24 h, and group III, reperfusion for 24 h after receiving monoclonal anti-ICAM-1 antibodies. At the end of the experiment, blood samples were collected for creatinine, lactate dehydrogenase, creatine phosphokinase, potassium, pH and leukocyte counts. Samples were taken from the muscles of the hind limbs and from the kidneys and lungs for histological analysis and measurement of the neutrophil infiltrate by myeloperoxidase staining. The groups did not differ significantly with regard to the laboratory tests. There were no major histological alterations in the kidneys. An intense neutrophil infiltrate in the lungs, similar in all groups, was detected. Myeloperoxidase determination showed that after reperfusion there was significantly less retention of polymorphonuclear neutrophils in the muscles (352 ± 70 vs 1451 ± 235 × 10² neutrophils/mg; P<0.01) and in the kidneys (526 ± 89 vs 852 ± 73 × 10² neutrophils/mg; P<0.01) of the animals that received anti-ICAM-1 before perfusion compared to the group that did not. The use of anti-ICAM-1 antibodies in this experimental model minimized neutrophil influx, thus reducing the inflammatory process, in the muscles and kidneys after ischemia and reperfusion of the hind limbs.

Correlation between symptoms of the irritable bowel syndrome and the response to the food extract skin prick test

The relationship between the irritable bowel syndrome (IBS) and food intolerance is not clear. We studied the cutaneous response to food antigens in 43 volunteers who were students and employees of the Faculty of Medicine of Universidade Federal Fluminense. Subjects were divided into 3 groups after evaluation for Roma II criteria for functional disease of the gastrointestinal tract: group I, 14 volunteers with IBS; group II, 15 volunteers with functional dyspepsia; group III, 14 volunteers without habitual gastrointestinal symptoms. The subjects were submitted to the skin prick test with 9 food antigen extracts, for a total of 387 skin tests (9 per volunteer). Of the 126 tests applied to group I, 24 (19.4%) were positive (a 3-mm wider papule than the negative control) and of the 135 tests applied to group II, 3 (2.3%) were positive. Of the 126 tests applied to group III, 6 (4%) were positive. The number of positive responses obtained in group I (IBS) differed significantly from the other 2 groups (P < 0.01). None of the volunteers with IBS reported intolerance to any isolated food. The higher reactivity to food antigens in group I compared to groups II and III suggests that intestinal permeability may be increased in patients with IBS.

Effects of melatonin on the ovarian response to pinealectomy or continuous light in female rats: similarity with polycystic ovary syndrome

The current study was conducted to investigate the relationship between melatonin and chronic anovulation. Adult (3-4 months old) female Wistar rats were submitted to pinealectomy: group I: pinealectomized ovariectomized melatonin-treated (N = 10); group II: pinealectomized ovariectomized placebo-treated (N = 12); group III: pinealectomized light-treated placebo-treated(N = 10) or maintained under continuous light; group IV: maintained under continuous light, ovariectomized melatonin-treated (N = 22); group V: maintained under continuous light, ovariectomized placebo-treated (N = 10); group VI: maintained under continuous light placebo-treated (N = 10). In order to assess ovarian modifications, unilateral ovariectomy was performed during the fourth month in groups I, II, IV, V and the other ovary was removed after 8 months. Ovariectomy was performed in groups III and VI only after eight months. Melatonin (200 µg/100 g body weight) dissolved in 0.02 ml absolute ethanol was injected intramuscularly daily during the last 4 months into groups I and IV. The other groups were treated with placebo (NaCl). The ovarian cysts were analyzed and their area, perimeter and maximum diameter, as well as the thickness of the ovarian capsule were measured. Daily colpocytological smears were performed throughout the study. Persistent estrous condition and ovarian cysts were observed in all groups. In pinealectomized rats the ovarian and vaginal alterations disappeared at the end of the study and in rats maintained under continuous light the vaginal and ovarian polycystic aspect was reversed only in those treated with melatonin. We conclude that melatonin may act on the ovarian response reverting chronic anovulation induced by pinealectomy or continuous light.

Effect of one stretch a week applied to the immobilized soleus muscle on rat muscle fiber morphology

We determined the effect of stretching applied once a week to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Twenty-six male Wistar rats weighing 269 ± 26 g were divided into three groups. Group I, the left soleus was immobilized in the shortened position for 3 weeks; group II, the soleus was immobilized in the shortened position and stretched once a week for 3 weeks; group III, the soleus was submitted only to stretching once a week for 3 weeks. The medial part of the soleus muscle was frozen for histology and muscle fiber area evaluation and the lateral part was used for the determination of number and length of serial sarcomeres. Soleus muscle submitted only to immobilization showed a reduction in weight (44 ± 6%, P = 0.002), in serial sarcomere number (23 ± 15%) and in cross-sectional area of the fibers (37 ± 31%, P < 0.001) compared to the contralateral muscles. The muscle that was immobilized and stretched showed less muscle fiber atrophy than the muscles only immobilized (P < 0.05). Surprisingly, in the muscles submitted only to stretching, fiber area was decreased compared to the contralateral muscle (2548 ± 659 vs 2961 ± 806 µm², respectively, P < 0.05). In conclusion, stretching applied once a week for 40 min to the soleus muscle immobilized in the shortened position was not sufficient to prevent the reduction of muscle weight and of serial sarcomere number, but provided significant protection against muscle fiber atrophy. In contrast, stretching normal muscles once a week caused a reduction in muscle fiber area.

Serum laminin, type IV collagen and hyaluronan as fibrosis markers in non-alcoholic fatty liver disease

Hepatic fibrosis in patients with non-alcoholic fatty liver disease is associated with progression of the disease. In the present study, we analyzed the discriminative ability of serum laminin, type IV collagen and hyaluronan levels to predict the presence of fibrosis in these patients. In this preliminary report, we studied 30 overweight patients divided into two groups according to the absence (group I, N = 19) or presence (group II, N = 11) of fibrosis in a liver biopsy. Triglycerides, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltranspeptidade, hyaluronan (noncompetitive fluoroassay), type IV collagen, and laminin (ELISA) were determined. Group II presented significantly higher mean laminin, hyaluronan, type IV collagen, and aspartate aminotransferase values, which were due to the correlation between these parameters and the stage of fibrosis in the biopsy (Spearman's correlation coefficient, rS = 0.65, 0.62, 0.53, and 0.49, respectively). Analysis of the ROC curve showed that laminin values >282 ng/ml were those with the best diagnostic performance, with 87% accuracy. Association of laminin with type IV collagen showed improvement in the positive predictive value (100%), but with reduction in diagnostic sensitivity (64%). When compared with the criteria of Ratziu et al. [Gastroenterology (2000) 118: 1117-1123] for the diagnosis of septal fibrosis, laminin values presented a better diagnostic accuracy (83 vs 70%). Determination of extracellular matrix components in serum, especially of laminin, may identify patients with non-alcoholic fatty liver disease and fibrosis and these components may be used as indicators for liver biopsy in these patients.

The role of secondary hyperparathyroidism in left ventricular hypertrophy of patients under chronic hemodialysis

End-stage renal disease (ESRD) patients frequently develop structural cardiac abnormalities, particularly left ventricular hypertrophy (LVH). The mechanisms involved in these processes are not completely understood. In the present study, we evaluated a possible association between parathyroid hormone (PTH) levels and left ventricular mass (LVM) in patients with ESRD. Stable uremic patients on intermittent hemodialysis treatment were evaluated by standard two-dimensional echocardiography and their sera were analyzed for intact PTH. Forty-one patients (mean age 45 years, range 18 to 61 years), 61% males, who had been on hemodialysis for 3 to 186 months, were evaluated. Patients were stratified into 3 groups according to serum PTH: low levels (<100 pg/ml; group I = 10 patients), intermediate levels (100 to 280 pg/ml; group II = 10 patients) and high levels (>280 pg/ml; group III = 21 patients). A positive statistically significant association between LVM index and PTH was identified (r = 0.34; P = 0.03, Pearson's correlation coefficient) in the sample as a whole. In subgroup analyses, we did not observe significant associations in the low and intermediate PTH groups; nevertheless, PTH and LVM index were correlated in patients with high PTH levels (r = 0.62; P = 0.003). LVM index was also inversely associated with hemoglobin (r = -0.34; P = 0.03). In multivariate analysis, after adjustment for age, hemoglobin, body mass index, and blood pressure, the only independent predictor of LVM index was PTH level. Therefore, PTH is an independent predictor of LVH in patients undergoing chronic hemodialysis. Secondary hyperparathyroidism may contribute to the elevated cardiovascular morbidity associated with LVH in ESRD.

Effect of iron overload on the severity of liver histologic alterations and on the response to interferon and ribavirin therapy of patients with hepatitis C infection

The objective of the present study was to determine the presence of hepatic iron overload in patients with chronic HCV infection and to correlate it with histologic alterations, HCV genotype and response to therapy. Liver tissue samples from 95 patients with chronic hepatitis C were divided into two groups: group I, presence of iron overload in hepatic tissue (Perls' staining) and group II, no iron overload. Hepatic iron overload was detected in 30 (31.6%) of 95 patients. Of the 69 patients tested by genotyping, 49 (71.01%) were genotype 1 and 20 (28.99%) genotype non-1. Iron overload was detected in 14 (28.6%) patients with genotype 1 and in 6 (30%) with genotype non-1 (P = 0.906). There was a significant difference in fibrosis stage between groups (P = 0.005). In group I (N = 30), one patient had stage F0/F1 of fibrosis, while in group II (N = 65), 22 (33.8%) patients had minimal or no fibrosis. Fibrosis stage F2/F3 was observed in 70% of group I patients compared to 46.2% of group II. Eighty-five patients were treated with a combination of interferon and ribavirin; 29 of them (34.1%) had a sustained virologic response and 8 (27.6%) of them had hepatic iron overload. Iron overload was detected in 18 (32.1%) of the 56 non-responders (P = 0.73). Hepatic iron overload was frequent among patients with chronic hepatitis C and was associated with a more severe stage of liver fibrosis. There was no association between iron overload and HCV genotype and response to interferon and ribavirin therapy.

Primary and secondary esophageal contractions in patients with gastroesophageal reflux disease

We studied the primary and secondary esophageal peristalsis in 36 patients with heartburn and acid regurgitation and in 14 asymptomatic volunteers. Primary peristalsis was elicited by ten swallows of a 5-mL bolus of water and secondary peristalsis was elicited by intra-esophageal infusion of 5, 10, and 15 mL water, 0.1 N hydrochloric acid and air. Esophageal contractions were measured by an 8-lumen manometric catheter assembly incorporating a 6-cm sleeve device. Contractions were registered at 3, 9, and 15 cm from the upper margin of the sleeve and the infusion was done through a side hole located at 12 cm. Twenty patients had normal endoscopic esophageal examination, 10 with normal (group I) and 10 with abnormal pH-metric examination (group II), and 16 had esophagitis (group III). The amplitude of contractions after swallows was lower (97.8 ± 10.0 mmHg) in the distal esophagus of group III patients than in controls (142.3 ± 14.0 mmHg). Patients of group III had fewer secondary contractions (water: 25% of infusion) than patients of the other groups and controls (67% of infusion). Patients of group III also had a lower amplitude of secondary peristalsis in the distal esophagus (water: 70.1 ± 9.6 mmHg) than controls (129.2 ± 18.2 mmHg). We conclude that patients with esophagitis have an impairment of primary and secondary peristalsis in the distal esophagus.

Leptin levels in different forms of Chagas' disease

Leptin is produced primarily by adipocytes. Although originally associated with the central regulation of satiety and energy metabolism, increasing evidence indicates that leptin may be an important mediator in cardiovascular pathophysiology. The aim of the present study was to investigate plasma leptin levels in patient with Chagas' heart disease and their relation to different forms of the disease. We studied 52 chagasic patients and 30 controls matched for age and body mass index. All subjects underwent anthropometric, leptin and N-terminal pro-brain natriuretic peptide (NT-proBNP) measurements and were evaluated by echocardiography, 12-lead electrocardiogram (ECG), and chest X-ray. All patients had fasting blood samples taken between 8:00 and 9:00 am. Chagasic patients were divided into 3 groups: group I (indeterminate form, IF group) consisted of 24 subjects with 2 positive serologic reactions for Chagas' disease and no cardiac involvement as evaluated by chest X-rays, ECG and two-dimensional echocardiography; group II (showing ECG abnormalities and normal left ventricular systolic function, ECG group) consisted of 14 patients; group III consisted of 14 patients with congestive heart failure (CHF group) and left ventricular dysfunction. Serum leptin levels were significantly lower (P < 0.001) in the CHF group (1.4 ± 0.8 ng/mL) when compared to the IF group (5.3 ± 5.3 ng/mL), ECG group (9.7 ± 10.7 ng/mL), and control group (8.1 ± 7.8 ng/mL). NT-proBNP levels were significantly higher (P < 0.001) in the CHF group (831.8 ± 800.1 pg/mL) when compared to the IF group (53.2 ± 33.3 pg/mL), ECG group (83.3 ± 57.4 pg/mL), and control group (32 ± 22.7 pg/mL). Patients with Chagas' disease and an advanced stage of CHF have high levels of NT-ProBNP andlow plasma levels of leptin. One or more leptin-suppressing mechanisms may operate in chagasic patients.

Comparison of the effects of lactated Ringer solution with and without hydroxyethyl starch fluid resuscitation on gut edema during severe splanchnic ischemia

The type of fluid used during resuscitation may have an important impact on tissue edema. We evaluated the impact of two different regimens of fluid resuscitation on hemodynamics and on lung and intestinal edema during splanchnic hypoperfusion in rabbits. The study included 16 female New Zealand rabbits (2.9 to 3.3 kg body weight, aged 8 to 12 months) with splanchnic ischemia induced by ligation of the superior mesenteric artery. The animals were randomized into two experimental groups: group I (N = 9) received 12 mL·kg-1·h-1 lactated Ringer solution and 20 mL/kg 6% hydroxyethyl starch solution; group II (N = 7) received 36 mL·kg-1·h-1 lactated Ringer solution and 20 mL/kg 0.9% saline. A segment from the ileum was isolated to be perfused. A tonometric catheter was placed in a second gut segment. Superior mesenteric artery (Q SMA) and aortic (Qaorta) flows were measured using ultrasonic flow probes. After 4 h of fluid resuscitation, tissue specimens were immediately removed for estimations of gut and lung edema. There were no differences in global and regional perfusion variables, lung wet-to-dry weight ratios and oxygenation indices between groups. Gut wet-to-dry weight ratio was significantly lower in the crystalloid/colloid-treated group (4.9 ± 1.5) than in the crystalloid-treated group (7.3 ± 2.4) (P < 0.05). In this model of intestinal ischemia, fluid resuscitation with crystalloids caused more gut edema than a combination of crystalloids and colloids.

cDNA and deduced primary structure of basic phospholipase A2 with neurotoxic activity from the venom secretion of the Crotalus durissus collilineatus rattlesnake

To illustrate the construction of precursor complementary DNAs, we isolated mRNAs from whole venom samples. After reverse transcription polymerase chain reaction (RT-PCR), we amplified the cDNA coding for a neurotoxic protein, phospholipase A2 D49 (PLA2 D49), from the venom of Crotalus durissus collilineatus (Cdc PLA2). The cDNA encoding Cdc PLA2 from whole venom was sequenced. The deduced amino acid sequence of this cDNA has high overall sequence identity with the group II PLA2 protein family. Cdc PLA2 has 14 cysteine residues capable of forming seven disulfide bonds that characterize this group of PLA2 enzymes. Cdc PLA2 was isolated using conventional Sephadex G75 column chromatography and reverse-phase high performance liquid chromatography (RP-HPLC). The molecular mass was estimated using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. We tested the neuromuscular blocking activities on chick biventer cervicis neuromuscular tissue. Phylogenetic analysis of Cdc PLA2 showed the existence of two lines of N6-PLA2, denominated F24 and S24. Apparently, the sequences of the New World’s N6-F24-PLA2 are similar to those of the agkistrodotoxin from the Asian genus Gloydius. The sequences of N6-S24-PLA2 are similar to the sequence of trimucrotoxin from the genus Protobothrops, found in the Old World.

Radioiodine plus recombinant human thyrotropin do not cause acute airway compression and are effective in reducing multinodular goiter

Recombinant human thyrotropin (rhTSH) reduces the activity of radioiodine required to treat multinodular goiter (MNG), but acute airway compression can be a life-threatening complication. In this prospective, randomized, double-blind, placebo-controlled study, we assessed the efficacy and safety (including airway compression) of different doses of rhTSH associated with a fixed activity of 131I for treating MNG. Euthyroid patients with MNG (69.3 ± 62.0 mL, 20 females, 2 males, 64 ± 7 years) received 0.1 mg (group I, N = 8) or 0.01 mg (group II, N = 6) rhTSH or placebo (group III, N = 8), 24 h before 1.11 GBq 131I. Radioactive iodine uptake was determined at baseline and 24 h after rhTSH and thyroid volume (TV, baseline and 6 and 12 months after treatment) and tracheal cross-sectional area (TCA, baseline and 2, 7, 180, and 360 days after rhTSH) were determined by magnetic resonance; antithyroid antibodies and thyroid hormones were determined at frequent intervals. After 6 months, TV decreased significantly in groups I (28.5 ± 17.6%) and II (21.6 ± 17.8%), but not in group III (2.7 ± 15.3%). After 12 months, TV decreased significantly in groups I (36.7 ± 18.1%) and II (37.4 ± 27.1%), but not in group III (19.0 ± 24.3%). No significant changes in TCA were observed. T3 and free T4 increased transiently during the first month. After 12 months, 7 patients were hypothyroid (N = 3 in group I and N = 2 in groups II and III). rhTSH plus a 1.11-GBq fixed 131I activity did not cause acute or chronic changes in TCA. After 6 and 12 months, TV reduction was more pronounced among patients treated with rhTSH plus 131I.