Castleman disease. Interaction with dermatopathy: Case report.

INTRODUCTION: Castleman disease (CD) is a lymphoproliferative disorder with lymph node hypertrophy. In the unicentric form (UCD), it affects one lymph node or chain of lymph nodes. In the multicentric form (DCM), there is hypertrophy of several lymph node chains with the formation of tumor masses, causing compressive symptoms. This case report showed a case of CD in a different location(inguinal region) associated to a multiple skin lesions. PRESENTATION OF THE CASE: We reported a UCD in a 43-year-old female patient with no previous comorbidities. Since January 2016, this patient developed erysipelas lesions of the left leg (LL) from the thigh root to the foot. Concomitantly, a tumor mass appeared in the inguinal region. In 2019 we performed a biopsy that revealed changes characteristic of CD. Due to extremely poor trophic conditions, the skin area with erysipelas was resected, and the raw surface was grafted. DISCUSSION: As an inference, the erysipelas may have been responsible for the subsequent lymphangitis, lymphedema and lymph node hypertrophy. CONCLUSION: Resection of the diseased skin and lymph node excision constitute the treatment of UCD and result in improvement of the clinical picture. Nevertheless, further study of the inflammatory reaction and of markers such as interleukin-6 and the presence of skin disorders in DC is needed.

Eye enucleation alters intracellular distribution of NO synthase in the superior colliculus.

We investigated the role of retinotectal projections on the distribution of nitric oxide synthase (NOS) in the retinoceptive layers of the rat superior colliculus (SC) using histochemical methods. Rats enucleated at birth showed no alteration in the temporal pattern of NOS expression. There was, however, a dramatic change in the NADPH-diaphorase staining pattern of NOS-positive cells. NOS was absent from the distal portions of the dendritic trees of the deafferented SC. Nevertheless, staining the dendritic trees of these cells with Lucifer yellow showed that they were not morphologically different from those of the ipsilateral SC of monoenucleated animals. The same results were obtained when enucleation was performed in adult rats. We conclude that NOS intracellular distribution in the SC cells can be regulated by retinotectal projections in both developing and adult animals.

Methamidophos: an anticholinesterase without significant effects on postsynaptic receptors or transmitter release.

Methamidophos (O,S-dimethyl phosphoroamidothiolate, Tamaron), an organophosphate (OP) anticholinesterase of limited toxicity, is widely used as an insecticide and acaricide. To provide additional insight into the molecular basis of its action, we have used electrophysiological and biochemical techniques to study the effects of methamidophos on the neuromuscular junction of rat and frog and on the central nervous system of rat. Methamidophos has a relatively weak inhibitory action on cholinesterases in rat diaphragm muscle, brain and hippocampal homogenates, with IC50 values on the order of 20-20 microM. An even weaker anticholinesterase activity was found in frog muscle homogenates, with the IC50 being above 300 microM. As further evidence of anticholinesterase activity, methamidophos (1-100 microM) was able to reverse the blockade by d-tubocurarine (0.5-0.7 microM) of neuromuscular transmission in rat phrenic nerve-hemidiaphragm preparations. Inhibition of cholinesterase activity by methamidophos was long lasting, which is consistent with the formation by the agent of a covalent bond with the enzyme's active serine residue. The action was also slowly reversible, which suggests spontaneous reactivation of the enzyme. electrophysiological studies at the rat neuromuscular junction showed that, due to its anticholinesterase activity, methamidophos increased the amplitude and prolonged the decay phase of nerve-evoked and spontaneous miniature end-plate potentials. In contrast to other OP compounds, e.g., paraoxon (Rocha et al., 1996a), methamidophos did not affect neurotransmitter release, nor did it interact directly with the muscle nicotinic acetylcholine receptor. Moreover, it contrast to paraoxon, methamidophos did not affect the whole-cell currents induced by application of acetylcholine, glutamate or gamma-aminobutyric acid recorded to cultured hippocampal neurons. Based on these data, methamidophos appears to have a selective effect on cholinesterase.

Patterns of nitric oxide synthase expression in the developing superior colliculus.

Nitric oxide (NO) is synthesized in cells of both the central and peripheral nervous system and has been implicated in several forms of synaptic plasticity. The enzyme that produces NO, nitric oxide synthase (NOS), can be visualized in the brain by the reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemistry technique (NADPH-d). We have used NADPH-d activity to detect the presence of NOS-positive cells in the developing rat superior colliculus. Our results showed that NOS is present in cells and neuropil in the developing and adult rat superior colliculus. The first NOS-positive cells appeared at postnatal day 7 and were weakly stained. The number and intensity of the NOS-positive cells increased progressively during the following days reaching a maximum at postnatal day 15. By the end of the third postnatal week, both the number and intensity of stained cells showed an adult-like pattern. The NOS-positive cells showed a Golgi-like morphology and we have found that all cell types present in the superior colliculus express the enzyme. The expression of NOS by tectal cells parallels the functional development of the retino-collicular and cortico-tectal projections and suggest that nitric oxide synthase-positive cells might be involved in this process. In this review we highlighted some of the recent descriptions of the expression of NOS in the mammalian visual system with emphasis in the superior colliculus and correlate these findings with several developmental events taking place in this structure.

Pathophysiological studies of neuromuscular function in subacute organophosphate poisoning induced by phosmet.

A 51 year old man developed progressive cranial and proximal muscle weakness, hyperreflexia and mental change. The disorder progressed over 9 days following the fifth weekly spraying with the organophosphate (OP) insecticide, phosmet, with limited symptoms of acute toxicity. Marked decremental responses of 50-80% on slow and fast rates of stimulation were improved to 15% by edrophonium or neostigmine. Intracellular recordings at the endplate region of intercostal muscle revealed small miniature endplate potentials (mepps), reduced mean acetylcholine sensitivity and normal membrane potentials. Electronmicroscopy revealed degeneration and regeneration of the endplates. This study demonstrates that OP poisoning due to phosmet can produce a subacute postsynaptic neuromuscular syndrome without marked symptoms of acute toxicity.

Effectiveness of oximes 2-PAM and HI-6 in recovery of muscle function depressed by organophosphate agents in the rat hemidiaphragm: an in vitro study.

Phrenic nerve diaphragm muscles of young adult rats were used to study the ability of the oximes 2-PAM and HI-6 to recover muscle function depressed by organophosphate (OP) agents. The single twitch of diaphragm muscles which were exposed to soman (0.2 microM) recovered after washing with saline for 3 hr, but the muscles pretreated with sarin (0.4 microM), VX (0.2 microM), or tabun (0.4 microM) showed only partial recovery. In addition, after 3 hr washing, the muscles pretreated with soman as well as with tabun did not recover the tetanus sustaining ability (TSA), yet complete recovery was observed with muscles pretreated with sarin and VX. These results indicate that the OPs have different effects on muscle contractile properties and that VX- and sarin-pretreated muscles recover equally well after wash with physiological solution. The recovery of twitch tension of diaphragm muscles by 2-PAM and HI-6 was similar to that achieved by washing with saline for 3 hr for sarin- and soman-exposed muscles. The most remarkable differences were seen in the recovery of TSA. Both 2-PAM and HI-6 recovered the TSA of muscles that were pretreated with sarin and VX. Although 2-PAM recovered the TSA after tabun pretreatment, HI-6 had no discernible effect. On the other hand, HI-6 recovered the TSA of soman-pretreated muscles but 2-PAM did not. The effectiveness of muscle function recovery was not related to the oximes' ability to reactivate AChE, thus indicating that the recovery of muscle contractility may be attributed to a direct effect of these compounds on the muscle.

Morphological and electrophysiological study of distal motor nerve fiber degeneration and sprouting after irreversible cholinesterase inhibition.

A single subcutaneous injection of a sublethal dose of the irreversible organophosphate sarin (0.08 mg/kg) in rats induced a non-Wallerian-type axonal degeneration of the neuromuscular synapse in the slow twitch, soleus muscle. These alterations of the endplate region were more obvious in the soleus than in the fast extensor digitorum longus muscle and were slowly reversible, complete recovery requiring about 10 days. Silver-cholinesterase staining and electrophysiological techniques were used to define the spatiotemporal evolution of prejunctional abnormalities. The non-Wallerian-type axonal degeneration of the neuromuscular synapse was characterized by bead or balloon-like varicosities of the focal, distal, and terminal nerve fibers and a retraction of terminal axons. Axonal degeneration was accompanied by junctional and extrajunctional membrane depolarization and was followed by nerve sprouting at focal, distal, and terminal nerve fibers. Transients similar to miniature endplate potentials were recorded along the muscle fiber at distances of 800-2500 microns away from the parent endplate. New ectopic endings, originating from the same endplate, were discovered adjacent to the terminal axon and also distant from the parent endplate. Very elaborate terminal arborization and occasional multibranching arose from a progressive growth sprout. The new sprouting may have served to compensate for the loss of synaptic contact caused by sarin. Thus the present study demonstrates a direct cytotoxic effect of sarin and indicates that this organophosphate agent may be an important neurotoxicological tool to understand the mechanisms involved in nerve sprouting.

Structure-activity relationship of reversible cholinesterase inhibitors: activation, channel blockade and stereospecificity of the nicotinic acetylcholine receptor-ion channel complex.

1. We have shown that all cholinesterase (ChE) inhibitors, in addition to their well-known anti-ChE activity, have multiple effects on the nicotinic acetylcholine receptor-ion channel (AChR) macromolecule resulting from interactions with the agonist recognition site and with sites located at the ion channel component. Activation, competitive antagonism and different types of noncompetitive blockade occurring at similar concentration ranges and contributing in different proportions result in complex and somewhat unpredictable alterations in AChR function. The question is now raised as to how each effect of these compounds contributes to their antidotal property against organophosphorus (OP) poisoning, and what set of actions makes one reversible ChE inhibitor a better antidote. Many lines of evidence support the importance of direct interactions with various sites on the AChR: 1) morphological and toxicological studies with (+) physostigmine showed that anti-ChE activity is not essential to protect animals against toxicity by irreversible ChE inhibitors; 2) (-)physostigmine is far more effective against OP poisoning; 3) open channel blockers such as mecamylamine with no significant anti-ChE activity enhance the protective action of (-)physostigmine; 4) neostigmine, pyridostigmine, (-)physostigmine and (+)physostigmine showed qualitatively and quantitatively distinct toxicity and damage to endplate morphology and function. 2. In prophylaxis and during the very early phase of OP poisoning, carbamates, especially (-)physostigmine combined with mecamylamine and atropine, could protect almost 100% of the animals exposed to multiple lethal doses of OPs. Electrophysiological data showed that (-)physostigmine, among several reversible ChE inhibitors, showed greater potency in depressing both endplate current (EPC) peak amplitude and tau EPC. Therefore, concerning neuromuscular transmission, it seems that the higher the potency of a drug in reducing endplate permeability, the better is its protection against OP toxicity. A reversible open channel blockade combined with some agonist property helps to decrease the effect of ACh at its agonist site and to reduce the ion permeability of open channels. It should be pointed out that, during the later phase of OP poisoning, AChR desensitization should be most prevalent. Thus, a drug that can remove the AChR from this rather irreversible state to a more reversible blocked state should be a better protector. Indeed, oximes such as 2-PAM and a more potent analog, HI-6, produce multiple alterations in AChR function that comprise increased channel activation and open-channel blockade.(ABSTRACT TRUNCATED AT 400 WORDS)

Enantiomer (+)physostigmine prevents organophosphate-induced subjunctional damage at the neuromuscular synapse by a mechanism not related to cholinesterase carbamylation.

The natural alkaloid (-)PHY is a reversible anticholinesterase carbamate, but in contrast, its optical isomer (+)PHY, is a very weak anticholinesterase. We have shown that treatment of rats with atropine and (-)PHY prior to injections of a lethal dose of the irreversible organophosphate sarin (0.13 mg/kg) not only protected 100% of the animals from lethality but also reduced the size of the subneural lesions of the nicotinic synapses of skeletal muscle. Similar protection against lethality is provided by pretreatment with (+)PHY. At the concentration used (0.3 mg/kg), there was no detectable inhibition of AChE activity. We have examined the protection afforded by (+)PHY or (-)PHY against lethality and myopathy due to organophosphate agents such as sarin. The major alterations in the soleus motor endplates 1 hr after drug treatment were as follows: (1) A single sublethal dose of sarin (0.08 mg/kg) produced enlarged, blistered, and severely disrupted subjunctional regions, with muscle damage extending beyond the endplate to include myofiber necrosis and subsequent phagocytosis; (2) (+)PHY (0.3 mg/kg) produced no obvious damage in the postjunctional region; (3) (-)PHY (0.1 mg/kg) had a selective effect in inducing irregularities of the subjunctional sarcomere band patterns without any gross vacuolization; (4) light microscopic data indicated that the combination of atropine and (+)PHY, or of atropine and (-)PHY (0.1 mg/kg), 30 min prior to a lethal dose of sarin, offered dramatic reduction in the average dimension of lesions. Lesions were detectable in most endplates but recognizable changes were markedly less severe than those seen in sarin myopathy. Few instances of extensive muscle damage and myofiber necrosis were visible.(ABSTRACT TRUNCATED AT 250 WORDS)

Structure-activity relationship of reversible cholinesterase inhibitors: activation, channel blockade and stereospeceficity of the nicotinic acetylcholine receptor-ion channel complex

We have shown that alt cholinesterase (ChE) inhibitors, in addition to their well-known anti-ChE activity, have multiple effects on the nicotinic acetylcholine receptor-ion channel (AChR) macromolecule resulting from interactions with the agonist recognition site and with sites located at the ion channel component. Activation, competitive antagonism and different types of noncompetitive blockade occurring at similar concentration ranges and contributing in different proportions result in complex and somewhat unpredictable alterations inn AChR function. The question is now raised as to how each effect of these compounds contributes to their antidotal property against organophosphorus (OP) poisoning, and what set of actions makes one reversible ChE inhibitor a better antidote. Many lines of evidence support the importance of direct interactions with various sites on the AChR: 1) morphological and toxicological studies with (+) physostigmine showed that anti-ChE activity is not essential to protect animals against toxicity by irreversible ChE inhibitors; 2) (-) physostigmine is far more effective against OP poisoning; 3) open channel blockers such as mecamylamine with no significant anti-ChE activity enhance the protective action of (-) physostigmine; 4) neostigmine, pyridostigmine, (-) physostigmine and (+) physostigmine showed qualitatively and quantitatively distinct toxicity and damage to endplate morphology and function. In prophylaxis and during the very early phase of OP poisoning, carbamates, especially (-) physostigmine combined with mecamylamine and atropine, could protect almost 100% of the animals exposed to multiple lethal doses of OPs...

The surface charge of Toxoplasma gondii: a cytochemical and electrophoretic study.

The surface charge of Toxoplasma gondii tachyzoites was evaluated by means of binding of colloidal iron hydroxide particles at pH 1.8, cationized ferritin particles at pH 7.2 and ruthenium red to the cell surface, as visualized by electron microscopy and by direct measurements of the electrophoretic mobility (EPM) of the cells suspended in solutions of different ionic strength and pH. At pH 7.2, T. gondii has a negative surface charge with a mean EPM of--1.1272 +/- 0.0917 micron.s-1 X V-1 X cm. No significant difference was observed between the EPM of living cells at 25 degrees C and that of glutaraldehyde-fixed cells. At lower pH, there is a decrease in the negative surface charge, with an isoelectric point at pH 3.5. At higher pH (greater than 10), there is an increase in the surface charge reaching an EPM of--1.5675 +/- 0.0848 micron.s-1 X V-1 X cm at pH 7.2. These results indicate that the surface of T. gondii contains both negatively and positively charged dissociating groups. Binding of cationized ferritin particles and ruthenium red throughout the cell surface of glutaraldehyde-fixed cells was observed. However, when living parasites were incubated at 4 degrees C in the presence of cationized ferritin some cells showed a uniform distribution of the label, others showed a patch-distribution and still in others no label was seen, indicating a process of mobility and shedding of surface anionic sites. Colloidal iron hydroxyde particles did not bind to the surface of T. gondii. Incubation of the parasites in the presence of neuraminidase from Clostridium perfringens or Vibrio cholerae or in the presence of proteolytic enzymes (trypsin or protease) did not interfere with the surface charge.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunocytochemical localization of cytoskeletal proteins and electron microscopy of detergent extracted tachyzoites of Toxoplasma gondii.

Actin was located in tachyzoites of Toxoplasma gondii by indirect immunofluorescence using anti-actin antibodies. Fluorescence was seen in the region of the conoid of almost all cells. In about 75% of the cells, the whole anterior region showed fluorescence and in about 25% of the cells fluorescence was seen in the posterior region. No fluorescence was seen when permeabilized parasites were incubated in the presence of NBD-phallacidin which binds to F-actin. This observation, associated to the fact that no microfilaments were seen in transmission electron micrographs of Triton X-100 extracted, tannic acid-glutaraldehyde (TA-GA) fixed cells, indicate that in tachyzoites of T. gondii actin is predominantly in the monomeric form (G-actin). No fluorescence was observed when permeabilized parasites were incubated in the presence of antibodies specific to desmin, vimentin and keratin. Examination of Triton X-100 extracted, TA-GA fixed parasites showed that the outer membrane was partially removed while the inner membrane complex was not, but had a corrugated aspect. Connections between the sub-pellicular microtubules and the inner membrane complex and between the latter and the outer membrane were seen.

Distribution of intramembranous particles and filipin-sterol complexes in the cell membranes of Toxoplasma gondii.

Toxoplasma gondii possesses a plasma membrane covering the whole cell and, below it, two closely apposed unit membranes interrupted at the anterior and posterior tips of the parasite and at the micropore. Density differences of intramembranous particles (IMP) were observed among the various membranes. The polyene antibiotic filipin was used for the detection of sterols in freeze-fractured membranes of the parasite. Protuberances with a mean diameter of 38 nm, indicative of the formation of filipin-sterol complexes, were seen in the P and E faces of the plasma membrane. The density of filipin-sterol complexes on the P and E faces of the plasma membrane was 130 +/- 45 and 101 +/- 50 protuberances/micron2, respectively. Few or no protuberances were seen on both fracture faces of the intermediate and inner membranes. The results obtained are discussed and compared with those obtained in other parasites enclosed with a complex membrane system.

On the cultivation of Trypanosoma cruzi in tissue cultures of the spinal and sympathetic ganglion from the chick embryo.

Trypanosoma cruzi was cultured in spinal and sympathetic ganglion cells of chick embryos. The "Y" and the "CL" strains were used for comparison, showing no differences in their tropism for the different cell types of the ganglion cultures. Nerve cells as well as satellite and Schwann cells served as host for the parasite's intracellular cycle. No toxic effect on the nerve cells was observed in heavily infected cultures. The destruction of the nerve cells is due to the multiplication of the parasites in the cell's cytoplasm. Its structure in the non parasitized nerve cells, even in direct contact with parasites, looks normal under the optical microscope and also shows no alteration in its ultrastructure.

On the cultivation of Trypanosoma cruzi in tissue cultures of the spinal and sympathetic ganglion from the chick embryo.

Foi feita a inoculacao de Trypanosoma cruzi em culturas de celulas de ganglios espinais e simpaticos de embriao de galinha.Para comparacao, foram usadas as cepas "Y" e "CL", as quais nao mostraram diferencas em seu tropismo para os diversos tipos celulares das culturas. Tanto as celulas nervosas como os satelites e as de Schwann serviram de hospedeiro para o ciclo intracelular do parasito. Nao foi observado efeito toxico sobre as celulas nervosas, mesmo em culturas fortemente parasitadas.A destruicao das celulas nervosas se deve a multiplicacao dos parasitos no citoplasma das mesmas, finalizando com o rompimento total. A estrutura do citoplasma nas celulas nervosas nao parasitarias, mesmo havendo parasitos em vizinhanca proxima, se apresenta normal sob o microscopio optico, nao se notando, tambem, alteracao na sua ultra-estrutura