Stereology and immunohistochemistry of the myocardium in experimental hypertension: long-term and low-dosage administration of inhibitor of the nitric oxide synthesis

Morphological changes in the myocardium after left ventricular hypertrophy, due to chronic experimental hypertension, require an understanding of the quantitative relationship between myocyte and nonmyocyte compartments forming the structural framework of the myocardium. Hypertension was induced by long-term low-dosage inhibition of nitric oxide synthesis by NG-nitro-L-arginine methyl ester (L-NAME) in rats. L-NAME (12 mg/kg) was given to animals in water ad libitum during 15 weeks. After this period, systolic blood pressure increased almost 50% as compared with that in the control group. Morphological changes in control and L-NAME animals were investigated with stereology and immunohistochemistry. Comparing control and L-NAME animals, the surface density of myocytes decreased 73.7% while the mean cross-sectional area increased 97.6% in L-NAME rats. The volume density of myocytes decreased 45.9% and the volume density of the interstitium increased 71.7% in L-NAME rats. No stereological difference was found in blood vessels comparing the two groups. Remodeling of the cardiac interstitium occurred with increased deposition of both fibronectin and type III collagen. Fibronectin was seen in both early and latter responses to infarction while type III collagen was seen mainly in areas of incomplete healing among myocytes and around intramyocardial branches of the coronary arteries. The long-term low-dosage administration of an inhibitor of the NO synthase such as L-NAME causes myocyte hypertrophy and early interstitial and perivascular fibrosis without important quantitative changes in microcirculation.

Myocardial repair with long-term and low-dose administration of a nitric oxide synthesis inhibitor. Myofibroblasts, type III collagen and fibronectin

OBJECTIVE

To study the healing process of the myocardium in hypertensive rats undergoing inhibition of nitric oxide synthesis.

METHODS

Two groups of animals were studied: one received L-NAME, 12 mg/kg/day, and the other was a control group. The presence of type III collagen, fibronectin, and alpha-smooth muscle actin-positive cells was assessed by immunohistochemistry.

RESULTS

Fibronectin was seen in both early and late lesions, while type III collagen was seen mainly in areas of incomplete healing, situated among myocytes and around the intramyocardial branches of the coronary arteries. Areas representing early and late lesions showed a population of spindle-shaped cells. Immunohistochemistry showed that these cells were positive for alpha-smooth muscle actin.

CONCLUSION

In the myocardium of hypertensive rats, the alpha-smooth muscle actin-positive cells are related to the accumulation of type III collagen and fibronectin in the areas of myocardial damage.

[Critical illness polyneuropathy: case report]

The critical illness polyneuropathy has an acute onset and an axonal predominantly motor nature. It occurs in sepsis or in multiple organ failure usually requiring mechanical ventilation in critical care units. Electroneuromyography corroborates the diagnosis. Usually it courses satisfactorily. We report on a 35-year-old female patient who, after a permanence in a critical care unit due to sepsis and removal of a dead phetus, developed tetraparesis. She had an important improvement in four months. Electromyography showed reduction of amplitude of motor and sensory action potentials, positive waves and fibrillations. The sural nerve biopsy showed axonmyelinic neuropathy. These findings are consistent with those in literature and we believe they support the diagnosis of critical illness neuropathy.

[Ulnar nerve palsy in leprosy without skin changes: biopsy of the superficial branch of the ulnar nerve in the hand]

Leprosy is one of the most common diseases of peripheral nerves in the world. In Brazil it is particularly frequent, being a major health problem. In tuberculoid leprosy the ulnar nerve is the most common affected nerve. Sometimes there are no skin changes. In these cases in spite of nerve thickening only the nerve biopsy is capable to make a specific diagnosis. We performed a biopsy in the dorsal sensory branch of the ulnar nerve in the hand in 17 patients with ulnar palsy with thickening of the nerve in the elbow, without skin changes. The pathological findings consisted mainly of: loss of fibers (14 cases), inflammatory infiltration (13), fibrosis (12), demyelination and remyelination (9), presence of granuloma (6) and presence of bacilli (5 cases). We conclude that in case of ulnar nerve palsy in leprosy without skin changes, the biopsy of the dorsal sensory branch of this nerve in the hand is a good procedure for the diagnosis of leprosy.

[Clarithromycin combined with pyrimethamine in cerebral toxoplasmosis--a report of 2 cases]

The authors report the use and the outcome of claritromycin associated with pyrimethamine in the treatment of toxoplasma encephalites in two patients with AIDS. Both patients had the diagnosis stablished on clinical grounds, positive sorology (IgG) for toxoplasmosis and computed-tomographic (CT) scan of the brain showing lesions consistent with T. gondii encephalitis. The two patients were initially treated with pyrimethamine and sulfadiazine, which was changed to clindamycin due to allergic reactions. These reactions (skin rash) occurred with clindamycin as well and the patients were treated with claritromycin and pyrimethamine. The scheduled regimens were 1.5 to 2 g of clarithromycin plus 25 mg of pyrimethamine. The clinical response was very good in both cases with regression of neurologic signs and encephalitic abnormalities observed on CT scan. The authors suggest that clarithromycin associated with pyrimethamine may be an alternative treatment for toxoplasmosis in AIDS patients, who cannot receive or tolerate sulfa treatment.

Pathology of the central nervous system in patients infected with the human immunodeficiency virus (HIV): a report of 252 autopsy cases from Brazil

The central nervous system (CNS) was studied in 252 HIV-infected patients from the States of Rio de Janeiro and São Paulo in Brazil, the regions with the highest incidence of AIDS in the country. We compared the frequency and morphology of opportunistic infections and CNS changes caused by the HIV, with those described in other series and briefly analysed the risk factors involved in our cases. There were CNS lesions in 230 cases (91.3%), 30 (11.9%) with multiple infections and/or tumours. Most infections were opportunistic (65.4%), including 15.4% viral and 50% bacterial, fungal or protozoal infections. The most frequent was toxoplasmosis (34.1%), followed by cryptococcosis (13.5%), cytomegalovirus (CMV) infection (7.9%) and nodular encephalitis (6.7%). Primary lymphomas were observed in 4% of the cases and HIV encephalitis or leukoencephalopathy in 10.7%. Other opportunistic and HIV associated lesions were present in a limited number of cases and there were also vascular and non-specific lesions. Our study confirms the high frequency of CNS lesions in HIV infected patients. They are morphologically similar to those previously described. However, the higher incidence of toxoplasmosis and cryptococcosis, a lower incidence of viral opportunistic and HIV-associated lesions, and the presence of rarer lesions such as histoplasmosis and chagasic encephalitis, differ from other series, and may reflect geographical and/or socio-economic factors.

Clinical and morphological study of calf enlargement following S-1 radiculopathy

Calf enlargement following sciatica is a rare condition. It is reported the case of a 28-year-old woman who complained of repeated episodes of lower back pain radiating into the left buttock and foot. One year after the beginning of her symptoms, she noticed enlargement of her left calf. X-ray studies disclosed L5-S1 disk degeneration. EMG showed muscle denervation with normal motor conduction velocity. Open biopsies of the gastrocnemius muscles were performed. The left gastrocnemius muscle showed hypertrophic type 2 fibers in comparison with the right gastrocnemius. Electron microscopy showed mildly increased number of mitochondria in these fibers. A satisfactory explanation for denervation hypertrophy has yet to be provided.

Lipomatous differentiation in a medulloblastoma

A surgically resected medulloblastoma of the left cerebellum in a 42-year-old man contained numerous mature fat cells; many of these adipocytes expressed glial fibrillary acidic protein (GFAP), S-100 protein, and vimentin as seen by immunocytochemistry. The cellular parts of the tumor showed varying immunoreactivities for GFAP, S-100 protein, neuron-specific enolase, and synaptophysin. It is concluded that this tumor exhibits a unique spectrum of differentiation along multiple lines, including transformation of neuroectodermal cells to fat cells. The significance of this new type of differentiation in primitive neural tumors remains to be elucidated.

[Striated muscle in protein malnutrition: an experimental study in albino rats]

The effects of undernutrition on the "gastrocnemius plantaris" muscle of young albino rats were observed with light and electronmicroscopy and were compared with controls. Pregnant rats received a diet containing 6.7% protein and the neonates had a 3.2% protein diet after weaning. A total number of 40 animals were distributed in two groups: one hypoproteic and one control. Half of the animals of each group were killed 15 days after birth and the remaining ones at 30 days. We could observe important reduction in the weight of the undernourished rats reaching about 50% when compared with the control animals. An important reduction in the diameter of muscle fibers was noted in undernourished rats. Histochemical reactions showed that not only the type I but also the type II fibers were involved, the latter being more severely reduced in size. Type II fibers os small diameter, resembling F (fetal) fiber were found in animals at 15 days indicating a delay in maturation. Ultrastructural evaluation of the muscle did not show specific changes except for a severe reduction in the caliber of fibers when compared with control animals. We concluded that there was hypoplasia and not atrophy of the muscular tissue in animals submitted to pre- and post-natal undernutrition. The present study, associated with others in which the spinal motor cells and peripheral nerves of undernourished rats were analysed, allow us to consider that with protein deprivation there is a delay in the development, a hypoplasia of the motor unit. We think that in infantile progressive spinal amyotrophy (Werdnig-Hoffmann disease) there is possibly hypoplasia and not atrophy of the type II fibers and we postulate that a metabolic proteic problem is involved in this disease.

Dengue: neuropathological findings in 5 fatal cases from Brazil

Neuropathological examination of 5 patients with dengue who died of shock in Rio de Janeiro during an outbreak in summer 1987, showed nonspecific lesions (edema, vascular congestion, hemorrhagic foci and perivascular lymphocytic infiltrates). In one case with delayed marked neurological symptoms, several foci of perivenous demyelination were observed. Neurological manifestations are various and not uncommon in dengue, but their anatomical substratum is not known. An immunopathological mechanism has been postulated in some cases but has never been demonstrated morphologically. The perivenous leukoencephalitis observed in one of our cases could represent the morphological substratum of such an immunological mechanism.

Lipoma of the midbrain. Post-mortem finding in a patient with breast cancer

Intracranial lipomas are rare, usually do not have clinical expression and are located more frequently in the corpus callosum. Other locations include the spinal cord, midbrain tectum, superior vermis, tuber cinereum, infundibulum and more rarely cerebellopontine angle, hypothalamus, superior medullary velum and insula. We report the case of a lipoma of the left inferior colliculus which was a post-mortem finding in a woman who died of breast cancer. Although there are reports of intracranial lipomas in patients with malignant tumors there is no explanation for the co-existence of the two tumors. The present tumor also includes a segment of a nerve which is not uncommon, but a less common finding was the presence of nests of Schwann cells within it, shown by immunohistochemistry.

[Cerebellar glioblastoma multiforme: report of a case in a child]

The authors relate a case of glioblastoma multiforme of the cerebellum in a nine-years old girl. They correlate this case with reports published and they think that this pathology is not so rare as believed. This is the second case report, in Brazil, in children.

[Familial myasthenia gravis: report of 2 brothers]

The familial form of myasthenia gravis is a relatively rare condition, occurring in about 3.4 per cent of myasthenic patients. Two familial cases with ocular myasthenia gravis are reported. They had a third brother who died probably with the same disease. Their parents are cousins. The authors made a brief approach of genetic, clinical, statistical and therapeutic aspects of the disease.

[Necrotizing myelopathy and neoplasms: clinico-pathological report of 2 cases]

Two clinico-pathological cases of necrotic myelopathies with a distant malignancy are presented. The first patient had histiocytic medullary reticulosis and the second one had a renal cell carcinoma. The authors referred to other similar cases found in the literature. In both patients the pathological features in the spinal cord were similar to the other cases reported, but in their first case they found an intense inflammatory reaction and hyperplasia of astrocytes into bizarre giant forms. The cause of necrotizing myelopathy associated with neoplasms remain unknown. The authors think that the presence of inflammatory reaction and the changes in the astrocytes in their first case are consistent with the effects of a virus.

[Analysis of inter and intrapathologist concordance and discordance in a comparative study of the Madrid and Ridley-Jopling classifications of leprosy]

Eighty-six patients of leprosy have been examined by three leprologists; they have been classified according to the Madrid classification and their lesions biopsied and sent to two pathologists for independent histopathological examination. The pathologists have not received any information regarding the cases. Firstly the "senior" pathologist (A) utilized the Madrid classification and the "junior" pathologist (B) the Ridley-Jopling classification. In a second phase, the "senior" pathologist utilized the Ridley-Jopling classification and the "junior" pathologist the Madrid classification. Both pathologists did not know their own previous histopathological diagnosis at the second phase. The analysis of concordance and discordance between the histopathological diagnosis of the two pathologists and for the same pathologist, on utilizing the two classifications, have elicited the following conclusions: 1. There has been more concordance between the two pathologists on utilizing the Madrid classification than the Ridley-Jopling classification for the lepromatous, borderline and tuberculoïd in reaction patients. 2. The comparison of the two classifications for each pathologist on "blindly" examination of the material, has shown more concordance for the "senior" pathologist than for the "junior" pathologist. 3. These observations have convoyed to the final conclusion that the Ridley-Jopling classification brings some difficulties to the pathologists with limited experience in leprology and therefore it should be utilized only by experienced pathologists. 4. This preliminary study shows the necessity of performing another one with larger number of patients, in the active phase, with larger number of pathologists, preferably from different countries, and by utilizing the same methodology of "blind" examination of the material.

[Post-anoxic myoclonic encephalopathy (Lance-Adams syndrome): anatomopathological study of 2 cases]

Two cases of Lance-Adams syndrome with anatomopathologic study are reported. There were evidences of diffuse neuronal degeneration in the brain. These changes were most seen in the neurones of the cortical layers, thalamus and subthalamic nuclei. The cells changes were similar to those seen in ischaemic disease. Some neurones showed intracytoplasmatic inclusions staining with the P.A.S. method. These inclusions were readily distinguished from the Lafora bodies.

[Comparative analysis of the clinical diagnosis of hanseniasis and the histopathological examinations performed according to the criteria of the Madrid and Ridley-Jopling classifications]

A comparative study of the Ridley-Jopling's (RJ) and of the Congress of Madrid's (CM) pathological criteria was made in the different clinical types and groups of hanseniasis. A concordance between both criteria was found in the Indeterminate group and in the regressive phases of the Virchowian (V), Tuberculoid (T) and Reactional tuberculoid (RT) types. Clinical RT was confirmed by pathology in 81.2% of the cases according to CM, whereas 46.2% were considered "Borderline" according to RJ. Out of the 48 clinically V patients, 17 (35.4%) were "Borderline" (BL-2, BL-1 and BB), but practically all were also pathologically V according to CM. It is concluded that there is no practical convenience in the establishment of histopathological sub-groups that do not perfectly agree with clinical criteria. The Authors stress the importance of the study of the plasmocytes in the V infiltrates, of the lymphocytes in all granulomas and of the differences in the involvement of the neural ends, specially between the T and V poles. The dyeing of lipids by the Sudan III is useful to perfectly characterize the V pole, recognize residual V structures, separate the sub-groups BT, BB and BL, help in the early diagnosis of V infiltrations and differentiate the edematous, diffuse, non-granular cytoplasmatic vacuolization of RT.

[Infiltration of central nervous system and meninges in lymphomas with leukemic conversion]

The cases of four patients with lymphoma with leukemic conversion, who exhibited neoplastic infiltration of the central nervous system and of the meninges are reported. The anatomo-pathologic study showed the presence of small nodules of leukemic cells, in two patients. The other two patients had clinical improvement after the use of metotrexate by spinal route so that the anatomopathologic study of their CNS and meninges showed no abnormality.

[Spinal cord compression as initial manifestation of Hodgkin's disease. Report of a case]

A case of Hodgkin's disease in which the first clinical manifestation was a radiculo-spinal compression is reported. The authors comment about the possible mechanisms to explain this radiculo-spinal compression in this granulomatosis.