Roberto Scelsi

The Cycloxygenase-2 inhibitor SC58236 is neuroprotective in an in vivo model of focal ischemia in the rat.

Focal ischemia was induced in the fronto-parietal region of rat brain, by injection of Rose Bengal, followed by light activation. Focal ischemia was accompanied by formation of PGD(2) peaking 60-90 min post irradiation and declining thereafter. Increased Cycloxygenase-2 (COX-2) expression was also observed. Control ischemic rats showed distinct morphological alterations with necrosis of neurons, glial cells and blood vessels, surrounded by a halo with pyknotic cells with cytoplasm swelling and vacuolization. Compound SC58236, a selective COX-2 inhibitor, dose-dependently prevented, ischemia-induced eicosanoid formation (area under the curve (AUC) of controls: 3.11 +/- 0.87; AUC of 20 mg/kg SC58236: 0.39 +/- 0.24), and caused significant reduction of damaged area (30.7 and 18.9% at SC58236 20 and 6.6 mg/kg), suggesting that selective inhibitors of COX-2 are neuroprotective.

Inhibition of prostanoid synthesis protects against neuronal damage induced by focal ischemia in rat brain

Changes in prostanoids concentration and effects of the non-specific COX inhibitor indomethacin on prostanoids levels and extension of tissue damage were studied following focal ischemia induction in the fronto-parietal region of rat brain. Ischemia was induced in animals bearing a transcerebral microdialysis probe by injection of Rose Bengal, a photosensitive dye, followed by light activation. Prostanoid levels were determined in the dialysate using immunoenzymatic techniques. PGD2 levels rose significantly up to 237+/-22 pg/ml compared to a basal level measured before ischemia induction which was below the detection limit. TXB2 changes were smaller and had a different time course. Treatment with indomethacin abolished the ischemia-induced PGD2 release and reduced the extent of injury to the area by 43+/-3.7%. These results suggest that prostanoid release may play an important role in neurodegenerative processes and that cyclooxygenase inhibitors may contribute to protect against cerebral tissue damage.

Intrathecal IgG synthesis in multiple sclerosis and other neurological diseases: A comparative evaluation by IgG-index and isoelectric focusing

SummaryIntrathecal IgG synthesis has been investigated by determining the IgG index and by isoelectric focusing in 30 cases of definite multiple sclerosis, in 15 cases of probable multiple sclerosis and in 128 patients affected by other neurological diseases. The blood-brain barrier function was evaluated at the same time by serum albumin/CSF albumin quotient and isoelectric focusing. The IgG index was found elevated in 73.3% of definite multiple sclerosis patients, while oligoclonal IgG bands occurred in 90%. In the other neurological diseases the IgG index was abnormally increased in 35.1% but IgG bands were present only in cerebrospinal fluid (CSF) in 1.5% and both in the CSF and serum in 7% of patients.The high capacity of isoelectric focusing to detect IgG oligoclonal bands in the CSF is pointed out as an extremely useful diagnostic tool in multiple sclerosis.ZusammenfassungDas Vorhandensein von IgG-Synthese im Nervensystem wurde mittels IgG-Index-Determination und mittels Isoelektrischer Fokalisation untersucht, und zwar bei 30 Fällen mit eindeutig diagnostizierter Multipler Sklerose, bei 15 Fällen, in denen Multiple Sklerose wahrscheinlich ist, und bei 128 Patienten, die andere neurologische Erkrankungen aufwiesen. Gleichzeitig wurde die Blut-Hirn-Schrankenfunktion untersucht mittels des Albuminserums des CSF-Albumin-Quotienten und Isoelektrischer Fokalisation. Es zeigte sich, daß der IgG-Index bei 73,3% der eindeutig diagnostizierten Multiple-Sklerose-Patienten erhöht ist, während bei 90% der Patienten das Vorhandensein von oligoclonalen Zonen nachweisbar war. Was die anderen neurologischen Erkrankungen betrifft, so war in 35,1% der Fälle der IgG-Index abnormal erhöht, während IgG-Bänder im Liquor nur bei 1,5% sowie beide bei 7% der Patienten im Liquor und im Serum vorhanden waren. Bei der Diagnose Multiple Sklerose wird der Isoelektrischen Fokalisation der höchste diagnostische Wert zugesprochen, um IgG-oligoclonale Bänder im Liquor nachzuweisen.

Blood Cells Glutathione Peroxidase Activity and Selenium in Multiple Sclerosis

In the present study, the plasma and erythrocyte Se concentration and the erythrocyte and leukocyte glutathione peroxidase (GSH-Px) activity in 20 patients affected by multiple sclerosis (MS) were compared with those of a group of healthy controls. The Se concentration in the food was also studied and found to be less than the minimum values suggested by the US Food and Nutrition Board. The erythrocyte Se levels were found to be similar in both MS patients and in controls, while the plasma Se values were higher in the MS patients. The Se-dependent GSH-Px activity in the erythrocytes was found to be lower in the MS patients while no difference was found in the two groups as far as the leukocytes were concerned. Our data confirm that of other authors and indicate that the modified GSH-Px activity found in erythrocytes of MS patients is independent from the Se concentration and probably due to genetic factors.

Toxic polyneuropathy due to n-hexane.

Three women developed a predominantly motor polyneuropathy following industrial exposure to an adhesive agent containing 80.4% of n-hexane as a volatile substance. Histological and electron-microscopic studies were carried out on sural nerve and on soleus muscle. In the nerve, there were polymorphous changes in both myelin sheaths and axons of large diameter fibres. Irregular and swollen myelin sheaths and segmental swelling of axons with dissolution of neurotubules and evident increase of neurofilaments were frequently observed. Polymorphous inclusion bodies were often present in Schwann cell cytoplasm. The small myelinated and unmyelinated fibres did not show significant changes. The muscles showed denervation atrophy and focal degenerative myopathic changes, with presence of lymphocytic infiltrates and phagocytosis. This study confirms the noxious effect of n-hexane on the peripheral nerve, with development, in our cases, of a toxic polyneuropathy and denervation muscular atrophy with consistent myopathic changes.

Effects of thallium on primary cultures of testicular cells

The objective of this in vitro study was to examine the response of mixed cultures of Sertoli and germ cells to treatment with thallium (Tl) at the range of concentrations that, in previous studies, was shown in vivo to affect reproduction. Cultures were prepared from the testis of Sprague-Dawley rats. Cultures containing approximately 3.75 x 10(6) cells/ml were treated with Tl concentrations corresponding to 35, 7, and 1.4 micrograms Tl/g testis, estimated from protein content of cultures. Observations at 24, 48, and 72 h after treatment showed a significant release of germ cells into the culture medium that was both concentration and time dependent. Cultures treated with 35 micrograms Tl/g testis showed a threefold increase in germ-cell detachment compared with controls after only 24 h of exposure. As the treatment time increased to 48 h of exposure, even cultures exposed at the lowest Tl concentration (1.4 micrograms Tl/g testis) showed significant loss of germ cells. After 48 h, cultures exposed to 7 micrograms Tl/g testis exhibited a 2.5-fold increase in germ-cell detachment, and those exposed to 35 micrograms Tl/g testis exhibited a 10-fold increase over controls. Morphological investigations of cell cultures showed evident loss of germ cells with significant reduction in prepachytene and pachytene spermatocytes and changes in the shape of Sertoli cells. These results are in agreement with in vivo studies, in which thallium treatment at comparable exposure levels manifested its earliest toxic testicular effects in Sertoli and germ cells. They also demonstrate the usefulness of this in vitro culture technique to assess toxic testicular damage rapidly.

Aminoacid recovery via microdialysis and photoinduced focal cerebral ischemia in brain cortex of rats

A photochemical method using the Rose Bengal dye as thrombogenic agent was employed to induce focal cerebral ischemia in frontoparietal cortex of rats. A transcerebral microdialysis probe was used to collect samples from ischemic cortical area. An increase in glutamate (6-fold) and in taurine (4-fold) within the first hour occurred. Neuropathological investigations demonstrate a reproducible damaged area surrounded by a thin peripheral area showing neuronal apoptotic phenomena. The method represents a reproducible model of focal cerebral ischemia with neuropathological aspects superimposable to those characteristic of thrombogenic stroke in man. This method could also be relevant in the study of neurotransmitters during the evolution of ischemia. Furthermore, the presence of apoptotic phenomena in the perilesional halo confirms an ischemic penumbra suggesting the significance of preclinical pharmacological trials.

Thallium-induced testicular toxicity in the rat

Reproductive tract functions were studied in adult male Wistar rats given 10 ppm thallium as thallium sulfate in the drinking water. After 60 days of treatment, spermatozoa isolated from the cauda epididymides and vas deferens showed reduced motility and immature germ cells were found in the tubular lumen. Histological examination of testes in thallium-treated animals revealed disarrangement of the tubular epithelium and ultrastructural changes in the Sertoli cells with cytoplasmic vacuolation and distension of the smooth endoplasmic reticulum. The activity of testicular beta-glucuronidase was significantly reduced whereas acid phosphatase and sorbitol dehydrogenase activities were unchanged. Plasma testosterone levels were within normal limits. No abnormalities in testicular morphology and biochemistry were seen in animals sacrificed at the end of the first month of thallium exposure. These findings indicate that the male reproductive system is a susceptible target site to toxic effects of thallium under chronic exposure. They also suggest a major involvement of Sertoli cells in the mechanism underlying thallium-induced testicular damage.

Clinico-pathological findings in a patient with progressive cerebellar ataxia, autoimmune polyendocrine syndrome, hepatocellular carcinoma and anti-GAD autoantibodies.

OBJECTIVE To report clinical and pathological findings of a patient with late onset insulin-dependent diabetes mellitus (IDDM), progressive cerebellar ataxia (PCA) and hepatocellular carcinoma (HCC). PATIENT A 64-year-old woman, with a long lasting IDDM, progressively developed a severe cerebellar syndrome and died 2 years after the onset of the symptoms for a systemic infection. Autoantibodies to antigastric parietal cell and anti-pancreatic islet cell resulted positive. Autopsy showed a selective loss of Purkinje cells in the cerebellum, with an increase of Bergmann glia and variable microglial proliferation; furthermore, it disclosed an HCC. GAD-Abs were detected both in serum and CSF. CONCLUSIONS Clinical and experimental reports suggest a possible role of neoplastic cells in producing GAD-Abs. We postulate, in our case, that HCC could have been responsible for an overproduction of GAD-Abs, leading to the onset of PCA. Thus, GAD-Abs could be considered as a paraneoplastic marker in a subgroup of patients with PCA.

Ischemia-induced glutamate release in rat frontoparietal cortex after chronic alcohol and withdrawal

High doses of ethanol increase stroke risk: in this context, a role for excitatory amino acids has been proposed. The present results show that, in frontoparietal cerebral cortex, chronic ethanol treatment (10% v/v in drinking water for 28 days) was able to slightly reduce glutamate release (evaluated through transdialysis coupled with high-pressure liquid chromatography) following focal ischemia as regards non-treated ischemic rats. This reduction was, however, not associated with decreased cerebral damage. In 24-h withdrawing rats, histological and morphometric analyzes showed an exacerbated cerebral damage coupled with higher glutamate and aspartate release compared to controls. These results suggest that adaptive changes following chronic ethanol consumption lead to an increased excitotoxicity that is particularly evident during the withdrawal condition.