Effects of long-term administration of Senna occidentalis seeds in the large bowel of rats

Plants of the genus Senna that contain anthranoides derivatives are frequently used as cathartics. Radiological studies have demonstrated that patients with chronic constipation who have used stimulant laxative have colonic redundancy and dilatation more frequently than patients who have not. The objective of the present work was to study morphological and histochemical changes of the lower gut after administration of Senna occidentalis seeds for a long period to rats, as observed in skeletal muscle fibers. Fragments of the lower gut of young and adult rats treated with S. occidentalis seeds (2% for 171 days and 3% for 61 days in the diet) were submitted to histological and histochemical analysis and to densitometry. The most important finding was decreased oxidative enzyme activity in smooth muscle cells and in myenteric neurons of the large bowel. As oxidative metabolism is essential for ATP and energy production, these results suggest that the functional intestinal disturbance caused by the chronic use of Senna occidentalis as a laxative can be due to a metabolic effect involving energy production, which would decrease colonic motility and cause functional colonic dilatation, but without any irreversible anatomic change.     

Biochemical characterization of bacteriophage lambda genome packaging in vitro

Bacteriophage lambda has been extensively studied, and the abundance of genetic and biochemical information available makes this an ideal model system to study virus DNA packaging at the molecular level. Limited in vitro packaging efficiency has hampered progress toward this end, however. It has been suggested that limited packaging efficiency is related to poor activity of purified procapsids. We describe the construction of a vector that expresses lambda procapsids with a yield that is 40-fold greater than existing systems. Consistent with previous studies, packaging of a mature lambda genome is very inefficient in vitro, with only 4% of the input procapsids utilized. Concatemeric DNA is the preferred packaging substrate in vivo, and procapsids interact with a nucleoprotein complex known as complex I to initiate genome packaging. When complex I is used as a packaging substrate in vitro, capsid utilization is extremely efficient, and 40% of the input DNA is packaged. Finally, we provide evidence for a packaging-stimulated ATPase activity, and kinetically characterize this reaction quantifying the energetic cost of DNA packaging in bacteriophage lambda.     

Influence of acute exercise on human platelet responsiveness: possible involvement of exercise-induced oxidative stress

The aim of this study was to evaluate in sedentary male subjects the effects of an acute bout of strenuous and moderate exercise on ex vivo platelet responsiveness and its possible relationship with exercise-associated modifications of oxidant-antioxidant status. An increased ADP- and collagen-evoked platelet aggregation associated with modified membrane fluidity and ion homeostasis was observed after exhaustive exercise. After moderate exercise, we found a decrease of platelet aggregation evoked by low concentrations of agonists. Strenuous exercise, but not moderate exertion, resulted in the enhanced accumulation of secondary products of lipid peroxidation, decreased total antioxidant capacity, including a diminished superoxide dismutase activity, and increased susceptibility of low-density lipoprotein (LDL) to in vitro oxidation. Acute elevation of plasma nitrite/nitrate (NO_X) content was observed following each single session of physical test, whilst the platelet NO_X content was decreased after strenuous exercise and increased after moderate exercise. Findings of the present study suggest that oxidative stress induced by acute strenuous exercise may interfere with platelet responsiveness most likely by promoting oxidized LDL-mediated platelet activation and by decreasing plasma and platelet-derived nitric oxide (NO) bioactivity. Moreover, our results further suggest that platelet responsiveness following an acute moderate physical stressor may depend on the efficiency of plasma and intraplatelet NO to desensitize platelets to agonist stimulation. Electronic Publication     

Effect of exercise to exhaustion on myeloperoxidase and lysozyme release from blood neutrophils

Exercise sessions (swimming in rats and treadmill running in humans) resulted in stimulation of neutrophil degranulation in the experiments with animals and in the human study. Myeloperoxidase (MPO) (+67%) and lysozyme (+51%) quantities in the plasma of rats increased significantly immediately after exercise. The blood plasma lysozyme concentration was increased by 41% at the 6th min of treadmill exercise in athletes. The blood concentrations of neutrophil proteins normalized both in humans and animals at rest. The neutrophil protein concentrations in blood increased in parallel with the decrease of their level in leukocytes. The neutrophil capacity for an oxidative burst was not changed by the exercise, but decreased for 3–6 h in the post-exercise period. Such dynamics of the oxidative burst activity suggest a lack of association between this parameter and the degranulation process. The neutrophil proteins that appear in blood during degranulation can be involved in enhancing the bactericidal potency of blood, the activation of granulopoiesis, neutrophil efflux from bone marrow, and the conditioning of blood endothelium for leukocyte extravasation. Electronic Publication     

Rebound hepatosplenomegaly in type 1 Gaucher disease

A 19-year-old male patient with type 1 Gaucher disease was put on regular biweekly infusions of alglucerase. After 1 yr of treatment, hepatic and splenic volumes decreased from 38 and 45 mL/kg to 31 and 34 mL/kg, respectively. In addition, hemoglobin concentration, platelet count and white cell count increased, acid phosphatase level decreased, and the patient gained weight and energy. Despite improvement, the patient refused enzyme replacement therapy (ERT) because of muscle rigidity, chest pain, trembling and anxiety, which he attributed to enzyme substitution. Two and 4.5 year after cessation of therapy, hepatic and splenic volumes increased to 36 and 53 mL/kg and to 53 and 110 mL/kg, respectively. The patient developed non-tractable hematuria because of compression and dislocation of the left kidney by the enlarged spleen, which necessitated splenectomy. This report suggests that cessation of ERT in Gaucher disease may result in severe and complicated rebound visceromegaly.     

Antioxidant profile in the circulation of patients with fibroadenoma and adenocarcinoma of the breast

OBJECTIVES: To correlate the extent of lipid peroxidation with the antioxidant status in the circulation of patients with fibroadenoma and adenocarcinoma of the breast. DESIGN AND METHODS: Ten fibroadenoma and thirty breast cancer patients and an equal number of age- and sex- matched normal subjects were chosen for the study. Lipid peroxidation as evidenced by thiobarbituric acid reactive substances (TBARS) and the status of the antioxidants superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST) ascorbic acid and vitamin E were estimated. RESULTS: Enhanced lipid peroxidation with concomitant depletion of antioxidants was observed in breast cancer patients as compared to normal subjects and fibroadenoma patients (p < 0.05). A similar pattern of changes was seen in fibroadenoma patients as compared to corresponding normal subjects (p < 0.05). CONCLUSION: This study has revealed an imbalance in the redox status in patients with fibroadenoma and adenocarcinoma of the breast.     

ACE inhibition modulates transforming growth factor-β receptors in the young rat

The renin-angiotensin system plays an important role in renal growth and development. Exposure of the neonate to angiotensin converting enzyme (ACE) inhibitors increases mortality and results in growth retardation and abnormal renal development. It has been demonstrated that ACE inhibition in the developing kidney reduces the renal expression of growth factors, which may account for renal growth impairment. This study was designed to investigate the relationship between renal growth impairment and the expression of transforming growth factor-1 (TGF-1), TGF- receptor I [TRI, activin-like kinase (ALK)-1 and ALK-5], and TGF- receptor II (TRII). Newborn rat pups were treated with enalapril (30 mg/kg per day) or vehicle for 7 days, and kidneys were removed for Western blotting of TGF-1, ALK-1, ALK-5, and TRII, and for RT-PCR of ALK-5 and TRII. TGF-1, ALK-1, ALK-5, and TRII were also detected by immunohistochemistry. Enalapril treatment resulted in an increased mortality (30.4%) by day 7, and reduced body weight and kidney weight (P<0.05 versus vehicle). Enalapril decreased renal TGF-1, ALK-1, and ALK-5 protein expression (P<0.05). Also, enalapril decreased ALK-5 mRNA expression (P<0.05). TRII expression was not changed by enalapril treatment. These results indicate that ACE inhibition in the developing kidney decreases TGF-1, ALK-1, and ALK-5 expression, which may account for renal growth impairment. TRII may not be modulated by ACE inhibition in the developing kidney.     

Eccrine duct carcinoma of the eyelid mimicking meibomian carcinoma: clinicopathological study of a case

Eccrine duct carcinoma belongs to a group of malignant sweat gland tumors showing de novo eccrine differentiation, but without features of benign adnexal counterparts. They are therefore likely to be confused with visceral adenocarcinomas that have metastasized to the lid. These tumors require important diagnostic considerations when adenocarcinoma is encountered in the lid in the absence of a known primary tumor. We present the case of a 60-year-old man with a nodule in the right upper eyelid that was histopathologically diagnosed as eccrine duct carcinoma of the lid. The differential diagnosis of eccrine carcinomas based on light microscopy, enzyme histochemistry, and immunohistochemistry is discussed, and a list of the various malignant eccrine tumors reported in the lid is presented.     

Glucose-6-phosphate dehydrogenase expression associated with NADPH-dependent reactions in cerebellar neurons

This review describes the variation of glucose-6-phosphate dehydrogenase (G6PD) activity in the main neurons of the molecular and granular layers as well as in the deep nuclei of the cerebellum as observed so far by optical and electron microscopy studies. Light microscopy and semiquantitative microphotometry of histochemical staining showed that the highest G6PD activity was expressed by Purkinje cells and neurons of the deep cerebellar nuclei; the elements of the molecular layer showed a diffuse G6PD staining, while the granular layer displayed only scattered G6PD activity. Electron microscopy analysis showed that the basket and stellate cells, as well as the Golgi cells, have a remarkable G6PD activity, while in the granule cells the enzyme was barely detectable. The results show that cerebellar G6PD activity changes with different neuron types as a function of its role in sustaining NADPH dependent pathways in these cells.