Inhibition of reverse transcriptase activity of HIV by polysaccharides of brown algae.

Brown algae have two kinds of acid polysaccharides present in the extracellular matrix: sulfated fucan and alginic acid. We have previously isolated and characterized fucans from several species of brown seaweed. The characterized fucans from Dictyotaceae are heterofucans containing mainly fucose, galactose, glucose, xylose, and/or uronic acid. The fucan from Fucus vesiculosus is a homofucan containing only sulfated fucose. We assessed the activity of these fucans as inhibitors of HIV from reverse transcriptase (RT). Using activated DNA and template primers poly(rA)-oligo(dT), we found that fucans at a concentration of 0.5-1.0 microg/mL had a pronounced inhibitory effect in vitro on the avian reverse transcriptase, with the exception of xylogalactofucan isolated from Spatoglossum schröederi, which had no inhibitory activity. The alginic acid (1.0 microg/mL) inhibited the reverse transcriptase activity by 51.1% using activated DNA. The inhibitory effect of fucans was eliminated by their desulfation. Furthermore, only xylofucoglucuronan from S. schröederi lost its activity after carboxyreduction. We suggest that fucan activity is not only dependent on the ionic changes but also on the sugar rings that act to spatially orientate the charges in a configuration that recognizes the enzyme, thus determining the specificity of the binding.

Neuroimaging in pineal tumors.

BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.

Lipidized giant-cell glioblastoma of cerebellum.

Glioblastoma multiforme is recognized rarely in the cerebellum. We describe a peculiar case with lipid accumulation in giant tumor cells, possibly the second example so far reported in this unusual location. A 46-year-old man with a 5-month history of headache, vomiting, dizziness and instability of gait, was found to have on magnetic resonance imaging an expanding mass situated deep in the left cerebellar hemisphere. The lesion was hypointense in T 1- and hyperintense in T2-weighted images, had poorly defined borders, peripheral edema and annular foci of contrast enhancement. Eight months after subtotal removal and radiotherapy, control MRI showed tumor recurrence with aggressive features. The patient was alive 15 months after operation but follow-up was eventually lost. Histologically, the tumor showed marked pleomorphism, with many giant cells characterized by finely vacuolated cytoplasm strongly suggestive of lipid accumulation. There were few, sometimes atypical mitotic figures and foci of endothelial proliferation. The tumor cells were strongly positive for GFAP, vimentin and S100 protein, all of which stressed the foamy appearance of the giant cells. About 15% of nuclei were positive for Ki-67. We considered the case to be a so-called lipidized glioblastoma, first recognized as a subtype by Kepes and Rubinstein [1981]. Differential diagnosis with anaplastic pleomorphic xanthoastrocytoma is discussed.

Orbital apex syndrome due to aspergillosis: case report.

We report the case of a 73-year-old female who presented facial numbness and pain in the first division of the trigeminal nerve, ptosis, diplopia and visual loss on the right side for the previous four months. The neurological, radiological and histological examination demonstrated a rare case of invasive fungal aspergillosis of the central nervous system, causing orbital apex syndrome, later transformed in temporal brain abscess. She died ten months later due to respiratory and renal failure in spite of specific antimycotic therapy.

Quantitative analysis of modes of invasion and lymph node metastases in oral squamous cell carcinoma.

The mode of tumor invasion has been suggested to have a relationship to the occurrence of cervical metastasis and to prognosis in oral squamous cell carcinoma (OSCC). However, a tumor usually does not have a single mode of invasion, and the importance, if any, of the relative proportions of different modes for metastatic potential has not been studied. Forty two cases of OSCC resected with cervical lymph nodes were selected, 20 of which had nodal metastases and 22 which had not. The mode of invasion in the tumor-host interface was classified as: I - pushing borders, II - bands, III - thin cords, IV - single cells and analyzed in 20 consecutive medium power fields. Also studied were other morphological parameters: perineural and angiolymphatic invasion, tissue eosinophilia, mitosis and intensity of inflammatory infiltrate at the tumor-host interface. The majority of the cases (95.2%) showed two or more modes of invasion. Modes I, II and III occurred with similar frequency in cases with and without metastases. Mode II was the commonest and most extensive in both groups. No mode of invasion was significantly associated with metastases, independent of its extension. The other morphological parameters were neither significantly associated with cervical metastasis. In conclusion, OSCC usually shows two or more modes of tumor invasion if a large extension of tumor-host interface is analyzed. However, the relative proportions of the modes have no correlation with the metastatic potential.

Chloroquine neuromyopathy.

A 59-year-old woman with rheumatoid arthritis was treated with prednisone and 250 mg of chloroquine diphosphate (CQ) daily. Though there was improvement in her joint symptoms, she began to notice progressive lower limb weakness, later extending to the arms and lasting for 2 months. Electromyography showed fibrillations, polyphasic potentials and high frequency discharges. Biceps brachii biopsy showed that virtually every muscle fiber and multiple small vacuoles surrounded by a basophilic rim. There was variation in fiber diameter and some fibers were atrophic and angulated. ATPase revealed type grouping. Electron microscopy showed, in each muscle fiber, numerous concentric membranous bodies, some with curvilinear profiles, beneath the sarcolemma or among the myofibrils. Some were also observed in endothelial cells of muscle capillaries. CQ was withdrawn, but no significant regression of symptoms had been observed at the time follow-up was discontinued. The patient died of cardiac insufficiency and bronchopneumonia. The case illustrates a rare complication of CQ therapy of rheumatic conditions. It is noteworthy because the drug was administered in therapeutic doses and only for a short period. CQ is known to interfere with lysosomal function, from which presumably the membranous bodies here described originate. Improvement of neuromuscular symptoms has been reported following withdrawal of the drug.

[Antigenic expression in human choroid plexus carcinoma: report of 2 cases]. / Expressão antigênica em carcinomas do plexo coróide humano: relato de dois casos.

Primary neoplasms of choroid plexus are rare. Six morphological variants have been described: papillary, cystic, acinar, mucus-secreting, oncocytic, and anaplastic. The anaplastic variant, the so-called choroid plexus carcinoma, is the rarest of all and can metastasize. The differential diagnosis of the anaplastic variant of choroid plexus neoplasms with adenocarcinomas, melanomas and undifferentiated neoplasms can be troublesome chiefly in adults. The now large use of immunocytochemical techniques in tissue section has become a powerful tool in the analysis of cell lineages, tumoral and non-tumoral. Nevertheless, the choroid plexus neoplasms have shown a complex and a somewhat confusing pattern of antigenic expression. In two choroid plexus carcinomas (one localized in the right lateral ventricle from a boy of 1 year and 9 months old, and the other localized in the left lateral ventricle from a girl of 3 years old) the following antigens were searched (using the avidin-biotin-peroxidase complex): glial fibrillary acidic protein (GFAP) with monoclonal and polyclonal antibodies; cytokeratins of 40-50kDa, cytokeratins of 60-70kDA (callus cytokeratin), neuronal specific enolase (NSE) and S-100 protein with monoclonal antibodies. The two neoplasms showed immunoreactivity against NSE, S-100 protein and cytokeratin of 40-50kDA. The neoplasm of the boy exhibited glial differentiation having immunoreactivity against GFAP with monoclonal and polyclonal antibodies.

Expressäo antigênica em carcinomas do plexo coróide humano: relato de dois casos / Antigenic expression in human choroid plexus carcinoma: report of 2 cases

Neoplasias provenientes do epitélio de revestimento do plexo coróide säo incomuns, tendo sido descritos 6 padröes morfológicos. O padräo anaplásico, também denominado carcinoma do plexo coróide, é o de menor freqüência e pode dar metástase fora do SNC. A distinçäo histológica desses tumores, particularmente da variedade anaplásica, com outras neoplasias primárias e metastáticas no SNC pode ser fidifícil. O uso de técnicas imunocitoquímicas em parafina tem-se mostrado útil no esclarecimento das linhagens tumorais. Os papilomas do plexo coróide têm, no entanto, sido objeto de controvérsia, por sua complexa expressäo antigênica. Usando a técnica de imunoperoxidase (sistema avidina-biotina-peroxidase) pesquisaram-se, em dois casos da variedade anaplásica, os seguintes marcadores: proteína glial fibrilar ácida (GFAP) com anticorpo monoclonal e policlonal; ceratinas de 40-50kDa, ceratinas de 60-70kDa (callus ceratina), enolase neuronal específica (NSE) e proteína S-100, com anticorpos monoclonais. Os dois tumores mostraram positividade para NSE, proteína S-100 e ceratina de 40-50kDa: uma das duas neoplasias mostrou diferenciaçäo glial, revelando positividade para GFAP tanto como anticorpo monoclona quanto policlonal

Isolation and characterization of hemorrhagic, myonecrotic and edema-inducing toxins from Bothrops insularis (jararaca ilhoa) snake venom.

Bothrops insularis snake venom was fractionated by gel filtration on Sephadex G-150 followed by ion-exchange chromatography on SP-Sephadex C-25. Two active fractions were purified to homogeneity: (1) SIII-SpI, approximate mol. wt 32,000 and N-terminal amino acid residue Val. This fraction showed esterase activity on TAME, edema-inducing activity on the rat hind paw and contractile activity on the isolated guinea pig ileum. The latter two activities were antagonized by benadryl plus methysergide; (2) SIII-SpVI, a myonecrotic and edema-inducing phospholipase, approximate mol. wt 29,000, N-terminal amino acid residue pyro-Glu, consisting of two chains of approximately 15,000 mol. wt each linked by disulphide bridge(s). The induction of edema by this fraction was not antagonized by benadryl plus methysergide, indomethacin, BW755C or BN52021, but it was antagonized by dexamethasone. Three highly purified hemorrhagic heterodimeric fractions, SIII-SpIII-3, SIII-SpIII-4 and SIII-SpIII-5, of approximate mol. wts 26,000, 29,000 and 26,000, and having N-terminal residues of Asx, Asx and Gly, respectively, were further isolated by preparative polyacrylamide slab gel electrophoresis. SIII-SpIII-4 and SIII-SpIII-5 increased the recalcification time of citrated rat plasma. None of the five isolated fractions showed any proteolytic (on casein) or kininogenase activity.

Fractionation of Bothrops jararacussu snake venom: partial chemical characterization and biological activity of bothropstoxin.

A myotoxin, bothropstoxin (BthTX), showing no detectable phospholipase A2 activity, was purified to homogeneity from the venom of the Brazilian snake Bothrops jararacussu by a combination of gel filtration on Sephadex G-75 and ion-exchange chromatography on SP-Sephadex C-25. Four phospholipases (Sm-SP1 to Sm-SPIV) were also isolated, the latter showing, similarly to BthTX (Sm-SPv) myonecrotic activity. Approximate mol. wts, as determined by SDS-PAGE, and pI of Sm-SPI to Sm-SPIV are: 22,400-4.2; 15,500-4.8; 13,800-6.9; and 13,200-7.7, respectively. BthTX is a single chain protein, approximate mol. wt 13,000, with 16 half-cystine residues, pI = 8.2 and LD50 = 7.5 mg/kg (i.p.) and 4.8 mg/kg (i.v.) for 20 g mice. The ten first N-terminal amino acid residues show a significant homology to other toxins with phospholipase structure. BthTX is specifically myotoxic, contrary to crude B. jararacussu venom which, although also myotoxic, affects intramuscular arteries and veins leading to thrombosis. BthTX and Sm-SPIV also differ from toxins isolated from the venom of other Brazilian snakes which are strongly hemorrhagic.

Muscular lesions induced by a hemorrhagic factor from Bothrops neuwiedi snake venom.

The local tissue effects of crude Bothrops neuwiedi snake venom and of its hemorrhagic factor (NHF) were studied on mouse tibialis anterior muscle in vivo. After 6 h, 8 days and 6 weeks the muscles were examined in paraffin sections stained with hematoxylin and eosin. Both NHF and crude venom produced hemorrhage and myonecrosis, later followed by muscle fiber regeneration. Intramuscular arteries also suffered necrosis. The minimal dose of NHF necessary to produce detectable hemorrhage and myonecrosis was 50 ng, while the minimal venom dose needed to produce the same effect was 20 times higher. The results indicate that NHF is one of the major factors responsible for the local effects of B. neuwiedi venom.

Pathological changes in muscle caused by haemorrhagic and proteolytic factors from Bothrops jararaca snake venom.

Haemorrhagic factor HF2 and bothropasin, two metalloproteins isolated from the venom of Bothrops jararaca, caused haemorrhage followed by myonecrosis and arterial necrosis after i.m. injection in mice. The effects of HF2 were qualitatively similar to those of bothropasin and crude B. jararaca venom, but its potency was about 20 times higher. The haemorrhagic and necrotizing actions of these components are unrelated to their proteolytic activity on casein.

Muscle necrosis and regeneration after envenomation by Bothrops jararacussu snake venom.

The lesions caused by sublethal doses of Bothrops jararacussu venom injected into tibialis anterior (tib. ant.) muscles of mice were studied with paraffin sections. Doses of 5 and 20 micrograms produced a large area of necrosis in tib. ant., but hardly affected neighbouring muscles. Phagocytosis of necrotic remnants was followed by marked regeneration of the muscle fibres. Within two weeks of the 5 micrograms dose there was recovery to near normal appearance and slight fibrosis. With 20 micrograms, a circumscribed scar and stronger interstitial fibrosis developed in the tib. ant. Most regenerated muscle fibres were small, but varied in diameter, retained central nuclei for three months (the longest survival) and were surrounded by collagen. Doses of 80 and 200 micrograms produced widespread coagulative necrosis of tib. ant., though neighbouring leg muscles were relatively spared. Myonecrosis was evident microscopically at 10 min, and over the next week the necrotic muscle remained acellular and devoid of inflammatory reaction except at the very edge. Blood vessels within and outside tib. ant. often became hyalinized and thrombosed. Phagocytosis of debris proceeded from the periphery, and after two weeks the muscle was replaced by fibro-adipose tissue. There was little if any muscle fibre regeneration. Abscesses developed in the vicinity of the injection site in several mice receiving high venom doses, but never after low doses or saline. Muscle necrosis after B. jararacussu venom seems due primarily to direct action of the venom, though vascular thrombosis and ischaemia may contribute. The venom can cause fibrosis of muscle and hinder or prevent muscle fibre regeneration.

Effects of Latrodectus spider venoms on sensory and motor nerve terminals of muscle spindles.

The effects of the venoms of the spiders Latrodectus mactans tredecimguttatus (black widow) and Latrodectus mactans hasselti (red back) on sensory nerve terminals in muscle spindles were studied in the mouse. A sublethal dose of venom was injected into tibialis anterior and extensor digitorum longus muscles of one leg. After survival from 30 minutes to 6 weeks muscles were examined in serial paraffin sections impregnated with silver or by electron microscopy. Sensory endings became swollen, some within 30 minutes, while over the next few hours there was progressive degeneration of annulospiral endings. By 24 hours every spindle identified by light or electron microscopy was devoid of sensory terminals. Degenerated nerve endings were taken up into the sarcoplasm of intrafusal muscle fibres. Regeneration of sensory axons began within 24 hours, new incomplete spirals were formed by 5 days and by 1 week annulospiral endings were almost all normal in appearance. Intrafusal motor terminals underwent similar acute degenerative and regenerative changes. These experiments show that intrafusal sensory and motor terminals are equally affected by Latrodectus venoms. Sensory nerve fibres possess a capacity for regeneration equal to that of motor fibres and reinnervate intrafusal muscle fibres close to their original sites of innervation.

Detection of repeated arsenical poisoning by neutron activation analysis of foot nail segments.

In one case of repeated ingestions of arsenic over a period of one year, the value of sectional toe nail analysis was investigated. The arsenic determinations were performed by instrumental neutron activation analysis. After subdividing the nail transversely into segments of 0.5 mm length, several maxima and minima of arsenic concentrations were found. Taking the nail growth into consideration, these characteristics of curve correspond to the known dates of treatments and of dismissals from the hospital. The results exclude an external arsenic contamination of the nail.

The effects of black widow spider venom on the innervation of muscles paralysed by botulinum toxin.

Botulinum toxin (BoTx) was injected into the muscles of one leg in mice causing local paralysis. Black widow spider venom (b.w.s.v.) was then injected into the paralysed muscles 3 or 15 d later. In both groups b.w.s.v. destroyed the nerve terminals poisoned by BoTx. In the 15 d group axonal sprouts, which had former due to the block of neuromuscular transmission by BoTx, were also destroyed. Within a few days the motor nerve terminal regenerated and the muscles recovered from paralysis at a faster rate than after BoTx alone. Recovery seemed to begin earlier in muscles where axonal sprouting was already advanced when b.w.s.v. was injected. The normal pattern of innervation was re-established in both groups, which was in marked contrast with muscles after BoTx alone where numerous sprouts and many ectopic end-plates had formed.

The neuromuscular junction of the mouse after black widow spider venom.

1. A sublethal quantity of black widow spider venom was injected into the calf muscles of mice. After 30 min to 6 weeks soleus muscles were examined by light and electron microscopy and by electrophysiological techniques. 2. Within 30 min motor nerve terminals were swollen and depleted for synaptic vesicles and by 6 h were disrupted and engulfed by Schwann cells. By 24 h every end-plate examined was denervated. Some preterminal myelinated axons also showed degenerative changes. 3. Re-innervation was first seen at 2 days. By 3 days axon terminals were present at most end-plates and by 8 days their morphology was nearly normal. The normal pattern of innervation of the muscle was re-established in that axons re-innervated their original end-plates and very few ultraterminal axonal sprouts were found. 4. Physiological study showed complete failure of transmission and absence of miniature end-plate potentials (m.e.p.p.s) and end-plate potentials (e.p.p.s) until day 3, when muscles responded weakly to indirect stimulation and m.e.p.p.s were recorded at 30% and e.p.p.s at 40% of fibres. The mean quantal content of e.p.p.s was low and there was rapid fatigue on repetitive stimulation. Extrajunctional sensitivity to acetylcholine developed within 1 day, was maximal at 3 days and declined to normal at 12-14 days. 5. The proportion of fibres at which m.e.p.p.s and e.p.p.s were recorded returned to normal by day 6 and mean quantal content was normal by day 9. 6. These findings show that the re-innervation of original end-plates is of importance in facilitating the rapid return of transmission to normal levels and limiting the extent of axonal growth.