Protective effect of early and late administration of pralidoxime against organophosphate muscle necrosis.

The objective of the present investigation was to study the protection afforded by a single administration of pralidoxime against the muscle necrosis induced by the organophosphate compound metamidophos at different times after intoxication. The fiber necrosis of the diaphragm muscle was quantified by a morphometric technique, comparing the area fraction occupied by necrotic muscle fibers in animals that received pralidoxime at different times after intoxication, i.e., 0, 1, 3, 6, and 12 h. Pralidoxime administration protected metamidophos-induced muscle necrosis in all groups studied except for the 12-h group. The earlier the administration of pralidoxime the greater the protection against muscle necrosis. This protection was not accompanied by complete reactivation of plasma cholinesterase activity. Results support the current opinion that pralidoxime should be administered as soon as possible after organophosphate intoxication, because in addition to reversing the muscarinic effects, early administration of pralidoxime also prevents muscle necrosis--which could impair muscular function and respiratory condition. The time difference between recovery of plasma cholinesterase activity and muscle necrosis protection indicates that this method is not completely trustworthy for patient follow-up, since some improvement may occur in spite of the low plasma cholinesterase activity.

Salpingitis due to Entamoeba histolytica.

We describe the pathology of a unique case of Fallopian tube amebiasis, associated with hydrosalpinx, in a 21-year-old woman. She complained of lower abdominal pain, had a foul-smelling green vaginal discharge and fever during one week. There was a discrete increase in body temperature and a painful abdominal palpation at the lower right side, with signs of local peritoneal irritation. Pathological examination showed a marked dilatation of the fallopian tube and hydrosalpinx. Microscopic examination showed a poorly formed granuloma composed of large macrophages with many Entamoeba histolytica trophozoites inside the fallopian tube. Even though it is a rare disease the correct diagnosis of female genital tract amebiasis is of great importance for the indication of proper therapy.

Salpingitis due to Entamoeba histolytica

We describe the pathology of a unique case of Fallopian tube amebiasis, associated with hydrosalpinx, in a 21-year-old woman. She complained of lower abdominal pain, had a foul-smelling green vaginal discharge and fever during one week. There was a discrete increase in body temperature and a painful abdominal palpation at the lower right side, with signs of local peritoneal irritation. Pathological examination showed a marked dilatation of the fallopian tube and hydrosalpinx. Microscopic examination showed a poorly formed granuloma composed of large macrophages with many Entamoeba histolytica trophozoites inside the fallopian tube. Even though it is a rare disease the correct diagnosis of female genital tract amebiasis is of great importance for the indication of proper therapy.

Expression of Ki-67 can assist in predicting recurrences of low-grade anal intraepithelial neoplasia in AIDS.

PURPOSE: The incidence of anogenital squamous-cell carcinoma was observed to have increased since the beginning of the human immunodeficiency virus infection epidemic among male homosexuals, both with acquired immunodeficiency syndrome and without acquired immunodeficiency syndrome. It seems that immunosuppression is the most important risk factor for the progression of anogenital lesions, recurrences of anal condyloma, and development of anal carcinoma, in particular in acquired immunodeficiency syndrome. High-grade anal intraepithelial neoplasia was predominantly observed in the human immunodeficiency virus-positive men. We have also observed a high rate of recurrences of anal lesions in cases of high-grade anal intraepithelial neoplasia. However, there are many cases of recurrences of low-grade anal intraepithelial neoplasia that cannot be predicted by routine histologic studies. By using immunohistochemical methods, we studied the expression of Ki-67 in epithelial cells of low-grade anal intraepithelial neoplasia of patients with acquired immunodeficiency syndrome to try to predict recurrence of these lesions. METHODS: Anal biopsies of 38 patients were studied retrospectively. Of these patients, 14 had no recurrences (Group 1), and 24 patients had recurrence of the anal lesions before one year of follow-up (Group 2). RESULTS: The median percentage of Ki-67-positive cells in Group 1 was 6.3 +/- 7.03 and in Group 2 was 24.1 +/- 16.72. The difference between Groups 1 and 2 was statistically significant (P < 0.001). CONCLUSIONS: Our results showed a high correlation between the percentage of Ki-67-positive cells and recurrences. We concluded that Ki-67 counting in low-grade anal intraepithelial neoplasia can aid in predicting recurrences and therefore aid in the follow-up of these patients.

Morphometric evaluation of nucleolar organizer regions in cervical intraepithelial neoplasia.

The objective of this study was to determine whether some morphometric parameters and two different methods of counting AgNOR dots were correlated with the grade of cervical intraepithelial neoplasia. Thirty uterine cervix biopsies (8 cases of cervicitis, 9 CIN I, CIN II and 6 CIN III) were studied. Two methods were used to count AgNOR dots. The first one consisted of counting the number of epithelial cells with 1, 2, 3, 4, or more dots. The second method, based on a computer analysis system, consisted of counting the total number of dots in 100 cells, without considering the number of dots per cell. Using the same computer analysis system, the following parameters were measured: area, diameter, perimeter, roundness and length of each dot. The following parameters were found to be correlated with the grade of intraepithelial neoplasia: 1) number of cells with 1 dot, which decreased with increasing grade of cervical intraepithelial neoplasia; 2) number of cells with 4 dots or more, which increased with increasing grade of cervical intraepithelial neoplasia; 3) total number of dots per 100 cells, which progressively increased with increasing grade of intraepithelial neoplasia. We conclude that counting cells with 4 or more dots is the more trustworthy parameter for distinguishing the grade of cervical intraepithelial neoplasia.

Progression of cervical lesions in HIV-seropositive women: a cytological study.

It has been reported that cervical intraepithelial lesions have a more aggressive course in HIV-seropositive than in HIV-seronegative women. In the present investigation, the progression of these cervical lesions was studied in a group of HIV-seropositive women. Of 1,587 patients, 200 (12.6%) had a cytological diagnosis of squamous intraepithelial lesion (SIL) or invasive carcinoma. In 409 patients, more than one cytological smear was collected in 3(1/2) years. Progression occurred in 39 cases. In 24 (61.5%), the first diagnosis was benign cellular changes (BCC) and the second was low-grade SIL (LSIL) (1-yr interval in 21 cases); in 11 (28.2%), the first was BCC, and the second, high-grade SIL (HSIL) (1-yr interval in 9 cases); in 2 (5.0%), the first diagnosis was LSIL. and the second, HSIL (1-yr interval); in 2 (5.0%), the first was HSIL, and the second, invasive carcinoma (2-yr interval). These results point to the importance of cervical cytologic surveillance in HIV-seropositive patients.

Expression of Ki-67 in cervical epithelial cells in preneoplastic lesions of patients with AIDS.

The objective of the present investigation was to study the expression of the proliferation marker Ki-67 in cervical intraepithelial lesions in women with AIDS. We studied 18 low-grade cervical intraepithelial lesions (Lo-CIN) and 8 high-grade cervical intraepithelial lesions (Hi-CIN ) in AIDS patients and 18 Lo-CIN and 14 Hi-CIN in patients from the general population. Positive Ki-67 nuclei were counted. A significantly higher number of Ki-67-positive cells (p < 0.001) was found in Lo-CIN of AIDS patients (mean 29.18 +/- 10.44) as compared with Lo-CIN of general-population women (mean 17.08 +/- 7.40), whereas no significant difference in positive Ki-67 nuclei was observed in the Hi-CIN of AIDS patients and of patients from the general population (p > 0.05). We conclude that the proliferative potential of cervical cells in Lo-CIN - as studied by the expression of the proliferation marker Ki-67 - is higher in AIDS patients than in the general population.

Histologic peripheral nerve changes in rats induced by deltamethrin.

Synthetic pyrethroid insecticides have been used in the last two decades largely because of their high activity as an insecticide and low mammalian toxicity. Some studies have demonstrated that these products, especially compounds with an alpha-cyano group, are toxic to the mammalian central nervous system (CNS) in acute intoxications. However, morphological studies are scarce. In the present work the histopathologic changes of the sciatic and tibial nerves of rats submitted to acute intoxication with the cyanopyrethroid deltamethrin were studied. For 3 consecutive days male Wistar rats received by oral gavage deltamethrin at a dose of 45 mg/kg body wt. On the 4th day fragments of sciatic and tibial nerves were studied by transmission electron microscopy (TEM) and teasing of individual nerve fibers. In addition, another group of rats were allowed to recover until the 10th day. Teasing of nerves of animals sacrificed on the 4th day revealed myelin ovoids, which are indicative of axonal damage. TEM demonstrated rare degenerated axons completely filled with organelles, in particular mitochondria, and with electron-dense lamellar bodies that resemble myelin figures. In addition, great cytoplasmic vacuolization caused by proliferation and dilation of the rough and smooth endoplasmic reticulum and Golgi apparatus was observed in some Schwann cells. No lesion was found 7 days after discontinuation of the treatment (group2). Since these histologic changes are transitory and scarce, the question arises: Are they related to the changes in NA(+), K(+)-ATPase activity or Na(+) channels caused by pyrethroid compounds?

Mitochondrial metabolism impairment in muscle fibres of rats chronically intoxicated with Senna occidentalis seeds.

The chronic administration of S. occidentalis seeds was found to induce a mitochondrial myopathy in hens. This study was undertaken to determine if the chronic treatment with S. occidentalis seeds of rats (as a mammalian model) would induce a mitochondrial myopathy similar to those described in humans and to determine if the histological changes could be correlated with the amount of ingested seeds. Twenty-one days old rats were fed S. occidentalis seeds at different diet concentrations (1, 2, 3%). Rats fed 1% S. occidentalis seeds had only a few COX-negative muscle fibers in the pectoralis major muscle. Rats fed 3% Senna occidentalis seeds had a greater number of COX-negative fibers. Rats fed 2% had an intermediate number of COX-negative fibers. Activity of SDH and NADH-tr were decreased in rats of groups 2% and 3%. Our data indicate that a progressive mitochondrial metabolism impairment can be produced in rats fed S. occidentalis seeds and that this impairment can be correlated with the amount of ingested seeds.

Skeletal muscle pathology in 2 siblings infected with Toxoplasma gondii.

Skeletal muscle can be the site of inflammatory diseases that lead to muscle weakness, pain, and increased myogenic serum enzymes. Most of these inflammatory myopathies are idiopathic. In some cases inflammatory myopathies are due to infectious agents. We describe the pathological aspects of muscle biopsies of 2 Brazilian siblings who acquired toxoplasmosis at the same time and in similar conditions. One developed a tetraplegia that was confirmed to be due to inflammatory myositis due to toxoplasma. The other developed myocarditis, with heart failure, without skeletal muscle weakness. In both cases many toxoplasma organisms were observed in the muscle biopsies, but in case 1 only was there an inflammatory myopathy with myofiber necrosis; the inflammatory cells were predominantly macrophages with some CD4+ cells and rare CD20+ cells. In case 1, expression of CD54 was observed in many inflammatory cells as well in endothelial cells, but only in endothelial cells in case 2. After treatment with clindamycin and corticosteroids both cases had only partial improvement, case 1 with a residual muscle weakness and case 2 with residual cardiac insufficiency (requiring digoxin). These cases show that the presence of the parasite in myofibers is not enough to induce an inflammatory myositis with muscle cell necrosis. This suggests that immunological disturbances may contribute to the development of inflammatory myositis due to toxoplasma.

The lysosomal enzymes acid phosphatase and cathepsin D in rats intoxicated with Senna occidentalis seeds.

Chronic administration of Senna occidentalis seeds induces an experimental toxic myopathy characterized by skeletal muscle fibers atrophy, decrease in histochemical activity of cytochrome oxidase, and increase of the acid phosphatase activity in muscle fibres at the light microscopic level. The mechanisms that lead to the increase of this lysosomal enzyme activity are not known and could be related to other biochemical disturbs than the mitochondrial function impairment. The main aim of the present study is to localize the acid phosphatase activity using a cytochemical method at transmission electron microscopy level and to quantify cathepsin D in muscle of rats chronically intoxicated with Senna occidentalis seeds by immunoblotting. Acid phosphatase was observed in lysosomes and over profiles of some organelles apparently not involved by lysosomal membrane. In addition immunoblotting demonstrated a decrease in the content of the precursor and of the mature form of cathepsin D in samples of muscles and liver of intoxicated animals. We concluded that there is a selective increase in acid phosphatase activity in muscle--and maybe in other tissues--of animals intoxicated with Senna occidentalis, that can be related to the skeletal muscle atrophy and the intense decrease in weight gain of these animals. Further studies should be performed to establish the mechanisms of selectivity in increase of lysosomal enzymes in different situations and pathological states.

Early expression of ubiquitin in myofibers of rats in organophosphate intoxication.

The degenerative process of the myofibers of the diaphragm of rats intoxicated with the organophosphate isofenphos, a compound that inhibits esterases, was studied at different intervals of intoxication. Early disorganization of the intermyofibrillar network and of the myofilaments, as well as dilatation of organelles, were observed by use of transmission electron microscopy. These changes precede macrophage invasion of the muscle fibers. Early expression of ubiquitin was observed in segments of muscle fibers by immunohistochemistry. Bands of polyubiquitin complexes in muscle homogenates were observed by immunoblotting. These bands disappeared in later stages of intoxication. A 42.5-kDa band corresponds to actin, as observed by immunoblotting using antisarcometric actin. This indicates relatively large amounts of polyubiquitin complex associated with sarcomeric actin in muscle fibers in early stages of intoxication. Based on these results it seems that actin is an important target in organophosphate-induced myofiber degradation and that the degradation of this protein-by the polyubiquitin pathway-may play an important role in the early disorganization of the sarcomere, as observed by electron microscopy. A possible role of the ubiquitin proteolytic pathway is that of trying to eliminate proteins modified in the early phases of muscle fiber degeneration, which is a necessary step for regeneration of the posterior segmental muscle.

Sarcoplasmic lipase and non-specific esterase inhibition in myofibers of rats intoxicated with the organophosphate isofenphos.

The expression of sarcoplasmic esterases, lipases as well as the lipid content in the myofibers of the diaphragm of rats intoxicated with the organophosphate isofenphos was studied. Lipid accumulation was documented at light, electron microsopic and by morphometric studies. The distribution of these lipid droplets was irregular and abundant in myofibers with numerous mitochondria (predominantly oxidative fibers). Histochemical inhibition of sarcoplasmic esterases and lipases was observed in the intoxicated animals. This sarcoplasmic inhibition of esterases occurs roughly in parallel to the inhibition of plasma cholinesterase activity. The inhibition of sarcoplasmic lipases may explain, at least partially, the accumulation of lipids. This inhibition probably makes difficult the use of lipids as fuel, especially in the oxidative fibers. In contrast to the small amount of muscle necrosis, (1.30+/-0.745), metabolic muscle impairment was intense and extensive, i.e., decreased activities of esterases and lipases in the sarcoplasm, that should contribute to muscle weakness. Therefore, because segmental necrosis was most prominent in oxidative fibers (and these fibers use lipids as the principal fuel and contain the greater amount of lipases in the sarcoplasm), it is possible that inhibition of activity of lipases is responsible for the segmental necrosis. Although the exact role of these metabolic changes is not known, it is possible that they contribute not only to the induction and evolution of muscle cell necrosis but also to the muscle weakness and clinical impairment of animals and humans in the acute intoxication by these compounds.

Cervical intraepithelial neoplasia in adolescents: study of cytological findings between 1987 and 1995 in São Paulo State-Brazil.

The purpose of the present study was to ascertain the frequency of Pap smears abnormalities (SIL/carcinoma) in two populations in the State of S. Paulo (Brazil) who were screened for cervical cancer during the last nine years: adolescents (up to the age of 21) and adults (over 21). Statistical analysis showed a tendency to linear increase in frequency of abnormal Pap smears in both groups (adolescent: slope = 0.118 +/- 0.56; adult: slope = 0.079 +/- 0.021), being greater in the adolescent group (slope 0.039 +/- 0.038) than in the adult group. Between 1987 and 1995 the prevalence of abnormal smears tripled in the adult group (from 0.37 to 1.18) and almost quadruplicated in the adolescent group (from 0.64 to 2.10). Low grade squamous intraepithelial lesions (SIL) were the most frequent findings in cervical cytology in both groups: 92.3% in the adolescent group and 69.8% in the adult group. Few cases of high grade squamous intrapeithelial lesions (HSIL) (7.7%) and no cases of carcinoma were found in adolescent population. We suggested that sexually active adolescents should be included in cervical screening programs.

Non-isotopic in situ hybridization of HPV types in cervical intraepithelial lesions in patients with AIDS.

Human papilloma viruses (HPVs), particularly types 16 and 18 have a key role in the development of preneoplastic and neoplastic lesions of the uterine cervix. We studied, by non isotopic in situ hybridization using probes to HPV 6, 11, 16 and 18, cervical biopsies from AIDS patients with condilomata or cervical intraepithelial neoplasia. There were 32 biopsies which showed low-grade cervical intraepithelial neoplasia (Lo-CIN); 5 biopsies showed high-grade cervical intraepithelial neoplasia (Hi-CIN). Of 32 Lo-CIN biopsies, 18 (56.3%) were positive for HPV; 7 for HPV 6 and/or 11 (21.9%), 11 for HPV 16 and/or 18 (34.4%) and one for HPV 6 and 18. Of 5 Hi-CIN biopsies 3 were positive for HPV: one for HPV 6 and 2 for HPV 16 or 18. The total positivity was 56.8% (21/37). This result was similar to those obtained by various other authors studying the general population.

Muscle atrophy induced in broiler chicks by parts of Senna occidentalis seeds.

Senna occidentalis (formerly Cassia occidentalis) is a common contaminant of agricultural commodities. It is toxic to cattle and poultry, reportedly being responsible for skeletal myodegeneration in these animals. All parts of the plant present toxicity, but the seeds are the most toxic. The toxin(s) responsible for the myodegeneration have not been definitively identified, nor is it known which part of the seeds is most toxic. Intoxication by this plant leads to weight loss with considerable economic repercussions. The effects of the whole seed and of parts of S. occidentalis seeds (1% in commercial feed) were compared on the pectoralis major muscle of broiler chicks intoxicated from birth until 22 days of life. There were severe clinical signals and reduced body weight in birds that received the external tegment of the seed, whereas no adverse effects were observed in birds that received the whole seed or other parts of the seed. Histological and morphometric studies showed an intense muscle fibre atrophy (both type 1 and type 2 fibres were affected) in the group that received 1% external tegment. This study may be the first step to identifying the substance(s) involved in this pathological process.

Protective effect of pralidoxime on muscle fiber necrosis induced by organophosphate compounds.

OBJECTIVE: To determine the protective effect of pralidoxime on muscle fiber necrosis induced by organophosphate acute intoxication in rats. DESIGN: Adult male Wistar rats were given oral organophosphate compounds dissolved in glycerol formal: dichlorvos, isofenphos, metamidophos, and diazinon. Half of the animals also received pralidoxime mesylate (20 mg/kg, intraperitoneal). Control animals received only the solvent. Twenty-four hours after treatment, the diaphragm muscle was collected for histological counts of necrotic muscle fibers in transverse sections. RESULTS: Metamidophos- and isofenphos-treated animals showed the highest percentage of necrotic muscle fibers: 1.66 +/- 1.112 and 1.34 +/- 0.320, respectively. Diazinon-treated animals had a lower percentage of necrotic fibers: 0.40 +/- 0.032 (p < 0.05) compared to the first 2 products, and dichlorvos-treated animals showed the smallest: 0.05 +/- 0.021 (p < 0.05) when compared to the other 3 products. Pralidoxime reduced necrotic fibers about 20 times in metamidophos-treated animals, 10 times in isofenphos-treated animals and 6 times in diazinon-treated animals. Pralidoxime administration did not increase plasma cholinesterase activity in any group, although symptoms were reduced. CONCLUSIONS: Oxime reduced diaphragmatic muscle necrosis in experimental organophosphate intoxication, despite little effect on plasma cholinesterase. Since respiratory insufficiency is an important cause of mortality and morbidity in organophosphate intoxications, early oxime administration may be particularly beneficial.

Nerve biopsy in patients with AIDS.

Patients with AIDS can present clinical involvement of the peripheral nervous system due to different causes. In the present work, it was studied the histopathological changes in sural nerve biopsy of fifteen patients with AIDS with this clinical involvement. It was observed the presence of a polyarteritis nodosa-like vasculitis of small arteries with fibrinoid necrosis in the sural nerve of 3 patients, one of them associated to polyradiculitis due to cytomegalovirus infection (CMV). Six patients presented mild axonal loss by light microscopy. Three other patients had a more important axonal neuropathy with myelin ovoids by teasing. By the electron microscopy in these patients were observed some fibers with axonal damage. The other three patients had normal sural nerves. We concluded that sural nerve biopsy may be important in peripheral neuropathies or myelo-radiculo-polyneuropathies in AIDS especially to search for nerve vasculitis, because it can change the therapeutic approach.

Squamous intraepithelial lesions in cervical smears of human immunodeficiency virus-seropositive adolescents.

Various authors have reported a high rate of human papillomavirus (HPV) infection and HPV-related neoplasias in human immunodeficiency virus (HIV)-seropositive women. On the other hand, young women are most susceptible to cervical infection because of immaturity of the cervix, as it appears that HPV has more access to the basal cells of the differentiating epithelium. The purpose of the present work was to study cervical smears of 82 adolescent HIV-seropositive women (13-21 years of age) to search for cytological evidence of cervical intraepithelial neoplasias. Twenty-one cases showed characteristic features of HPV infection and squamous intraepithelial lesions (SIL; 25.6%). Sixteen cases aged from 17 to 21 years (mean age 19.5 years) had low-grade SIL (LSIL; 19.5%) and five cases aged from 18 to 21 years (mean age 20.2 years) had high-grade SIL (HSIL; 6.1%). There was no significant difference between the mean age of patients with LSIL and HSIL. Two cases had atypical squamous cells of undetermined significance (ASCUS). In the present work it was found that HIV-seropositive adolescents have a high risk for preneoplastic lesions of the cervix (25.6%) as well as a high incidence of more aggressive lesions (6.1% of HSIL) when compared to the general population of adolescents. As it can be assumed that, if the age of acquisition of the infection in both groups (in the general population and HIV-seropositive women) is the same, it is probable that HIV infection in adolescents not only increases the frequency of HPV infections but also facilitates the evolution to more aggressive preneoplastic lesions of the cervix due to HPV.