Nilda Maria Perez

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.

Miotoxicidade por organofosforados

Organophosphates comprise a group of chemical compounds extensively used in farming as insecticides, which cause accidental poisoning in animals and men and are also used in suicide attempts. The toxicity of these compounds is due especially to the cardiac and respiratory impairment in consequence of autonomic nervous system disorders. However, it is known that some of these products induce a myopathy in experimental animals and humans. This myopathy is characterized by muscle cell degeneration, involving above all the respiratory muscles. Based on the fact that this involvement certainly enhances the respiratory impairment, this study offers an experimental method for routine evaluation of organophosphate myotoxicity, using a minimal and sufficient battery of stains and histochemical reactions, for muscle necrosis quantification. For this purpose, albino rats (Wistar) treated with the organophosphate paraoxon, were used both with and without antidotes (atropine or pralidoxime). Muscle fiber necrosis in the diaphragm of the rats treated with paraoxon or paraoxon and atropine, that affected about 15% of the fibers in some areas, was detected. In the group treated with paraoxon and pralidoxime, a minimal necrosis was seen, revealing a protective role of this later antidote during the development of myopathy.

FOXP3+ regulatory and TIA-1+ cytotoxic T lymphocytes in HIV-associated Hodgkin lymphoma

Human immunodeficiency virus (HIV) infects CD4+ lymphocytes, leading to a development of malignant lymphomas, such as HIV‐associated Hodgkin Lymphoma (HIV‐HL). This study aimed to assess the differences in cellular composition of the inflammatory reactive background of HIV‐HLs. We examined infiltrating T lymphocytes, specifically regulatory T cells, cytotoxic cells, Epstein‐Barr virus (EBV) related antigens and HIV‐receptor CCR5. In all HIV‐HL cases, Hodgkin and Reed‐Sternberg (HRS) cells showed EBER1 expression, LMP‐1 staining positivity and EBNA‐2 staining negativity, except for one case which showed LMP‐1 staining negativity. Our histological findings indicate the percentage of CD8+, TIA‐1+ lymphocytes was significantly higher in HIV‐HL than in non‐HIV‐HL cases (P < 0.05). On the other hand, the percentage of CD4+, FOXP3+ lymphocytes was significantly lower in HIV‐HL than in non‐HIV‐HL cases (P < 0.05) but present. The percentage of CCR5+ lymphocytes was significantly lower in HIV‐HL than in non‐HIV‐HL cases (P < 0.05). Usually, CD4+ and CCR5+ lymphocytes are reported to be rarely detected in HIV‐associated non‐Hodgkin lymphomas, but the presence of CD4+ and/or FOXP3+ lymphocytes may be implicated in the pathogenesis of HL. In addition, although additional CD8+ lymphocytes are probably not EBV‐LMP specific cytotoxic T‐cells, these lymphocytes may also well be involved in the pathogenesis of HIV‐HL.

Muscle pathology in juvenile dermatomyositis

OBJECTIVE To study muscle biopsies, using histochemistry, on ten children with infantile dermatomyositis. DESIGN Series of ten patients (of whom eight patients had received treatment and two had not) were submitted to muscle biopsy in order to diagnose possible inflammatory myopathy or to detect recurrences. PLACE OF DEVELOPMENT OF THE STUDY: Public Health Service of São Paulo State. PARTICIPANTS Children with clinical features of inflammatory myopathy. INTERVENTION Biopsies were performed on the vastus lateralis using local anesthetic. Histochemistry was performed according to standardized methods. RESULTS Architectural changes of the muscle fibers, necrosis of variable intensity and accentuated evidence of regeneration were observed in patients who had not received treatment (2 cases) and in one case where muscular weakness persisted in spite of corticosteroid therapy. Necrosis and regeneration were minimal or absent in cases treated for one year or more (4 cases). In 3 cases with clinical and laboratorial recurrences, muscle necrosis and architectural changes were detected. CONCLUSIONS It was concluded that muscle biopsy could aid in diagnosing infantile dermatomyositis as well as in detecting recurrences even in cases without clinical activity of the disease.

Inmunohistoquímica en un caso de encefalitis por virus de Epstein Barr

EBV can produce a broad range of CNS disorders such as demye-linative diseases, acute encephalitis, cerebellar ataxia, myelitis, or meningitis. The role of EBV itself in acute encephalitis is not completely clear. Presently we described a 4 years old boy with EBV encephalitis that deceased after respiratory distress and cardio-respiratory arrest. At autopsy the most important changes in the brain were focal sub cortical peri-vascular mononuclear inflammation of the cerebral vessels. EBV antigens were demonstrated by immunohistochemistry in some cells of the vascular walls and in some glial cells of the brain. As expected this indicates a predominantly cellular response in the brain. The presence of EBV antigens by immunohistochemistry associated to a scarce inflammatory infiltrate supports the hypothesis that EBV itself plays a major role in the pathogenesis of EBV encephalitis.EBV can produce a broad range of CNS disorders such as demyelinative diseases, acute encephalitis, cerebellar ataxia, myelitis, or meningitis. The role of EBV itself in acute encephalitis is not completely clear. Presently we described a 4 years old boy with EBV encephalitis that deceased after respiratory distress and cardio-respiratory arrest. At autopsy the most important changes in the brain were focal sub cortical peri-vascular mononuclear inflammation of the cerebral vessels. EBV antigens were demonstrated by immunohistochemistry in some cells of the vascular walls and in some glial cells of the brain. As expected this indicates a predominantly cellular response in the brain. The presence of EBV antigens by immunohistochemistry associated to a scarce inflammatory infiltrate supports the hypothesis that EBV itself plays a major role in the pathogenesis of EBV encephalitis.

Effects of nicotine administration in developing muscle fibers of rats offspring

The authors studied the effects of nicotine in developing skeletal muscles of rats. Pregnant Wistar rats received an enteral dose of nicotine (2.5, 5.0 or 10mg/kg, respectively, in groups G2, G5, and G10) from the 10th to the 18th or 20th days of pregnancy. Myotube atrophy was observed mainly in 20-day-old fetuses of G10. Twenty-day-old control fetus and of G2 and G5 had a high sarcoplasmic expression of desmin (weaker in G10). Vimentin expression was similar in 18-day-old fetuses of the control, G2, and G5 groups, but it was weaker in 20-day-old fetuses of the G2 and G5 groups. This would indicate an acceleration of the maturation pattern of vimentin expression in these intoxicated fetus. In conclusion, high doses of nicotine induce myotube atrophy and decrease of the expression of intermediate filaments, whereas relatively low doses of nicotine (G2 and G5) induce an early decrease of vimentin expression with no myofiber atrophy.