Binding of monoclonal anti-myelin-associated glycoprotein antibodies to human foetal peripheral neurons in culture

Dorsal root ganglion cells, obtained from 8-10-week human foetuses, were isolated by enzymatic procedure and grown on poly-L-lysine-coated coverslips. Most of the cultured cells showed the ultrastructural and immunological features of normal peripheral neurons. By immunocytochemistry neurons reacted with IgM antibodies with specificity for myelin-associated glycoprotein (MAG) from patients affected with IgM k gammopathy and peripheral neuropathy. The antigen was located on the plasmalemma of both perikarion and axon. We suggest that anti-MAG antibodies do not recognize neuronal MAG, but rather an epitope shared with different glycoproteins.

Giant axonal neuropathy: acceleration of neurofilament transport in optic axons

Giant axonal neuropathies are a group of acquired and inherited human diseases morphologically characterized by accumulation of neurofilaments (NF) in enlargements of preterminal regions of central and peripheral axons. Slow axonal transport was studied in the optic systems of rats treated with 2,5-hexanedione, a toxic compound that produces an experimental model of giant axonal neuropathy. The transport rate of NF and of two other polypeptides of Mr 64,000 and 62,000 were selectively increased. Other components of the slow axonal transport were not affected. Acceleration of labeled NF was also observed when 2,5-hexanedione was given after [35S]methionine administration. Morphometric analysis revealed that the number of NF and the axon size were decreased in regions of optic axons proximal to the enlargements. It is suggested that acceleration of NF transport leads to a longitudinal redistribution of NF: NF decrease proximally and increase distally, forming NF-containing enlargements. Evidence was obtained that polypeptides of Mr 64,000 and 62,000 are cytoskeletal components related to intermediate filaments, normally migrating with the component a of the slow axonal transport. The 2,5-hexanedione axon may provide insight into the pathogenesis of inherited and acquired giant axonal neuropathies and offers a model to investigate the relationship between number of NF and axonal size in central axons.

[Incidence and antibiotic resistance of various species of staphylococci in a hospital environment in eastern Sicily]

In this work we carry out an epidemiologic investigation of the incidence of Staphylococci in some hospitals of east Sicily, in relation with hospitalized patients. The tests were performed every ten days for a period of four months, by using Fisher technique. The strains were isolated from clinical specimens from hospitalized patients, and after identification, we made antibiotics-resistance essays. The results show a correlation between Staphylococcus strains isolated from patients and that of environmental origin, also for the antibiotics resistance spectrum.

[Hypertrophic neuropathies beginning in infancy: a study of 3 cases (author's transl)]

The genetical forms of hypertrophic neuropathies, inherited either as recessive or autosomal dominant trait, are classified, according to Dyck (1975), as HMSN type I, III, and IV. Sporadic cases are also reported. We studied three patients, one with autosomal recessive inheritance, and two without family history, who had the following common features: --onset of symptoms before the age to two years; --slowly progressive course; --peroneal muscular atrophy with absent tendon reflexes; --reduction of MCV and SCV; --decreased number of myelinated fibers; --schwannian cell hyperplasia, with onion bulb complexes formation; --absence of aspects of hypomyelination; --increased number of collagen pockets and denervated Schwann-Remak cells or processes. On light microscopy, multilamellated onion bulbs of large size were found in a very high percentage in case 1, while there were either simple in type or in a lower percentage in case 2. In the third, case, onion bulbs were recognized only on electron microscopy. It is known that in the various kinships affected with type I of HMSN, the pathological changes of peripheral nerves differ greatly. Therefore, despite early onset of symptoms and varying degree of severity of nerve changes, all three cases have been classified within the group of HMSN type I. The different severity of nerve damage may suggest the possibility of a genetical heterogeneity in this disorder.

Chronic relapsing polyneuritis. A light- and electron-microscopic study

The clinico-pathologic findings in two patients with chronic relapsing polyneuritis are reported. The patients had several attacks of diffuse polyneuritis followed by partial recovery. The tendency to persisting disability increased following relapses and in the late stages there was a progressive motor deterioration suggesting a continuing activity of nerve damage. The biopsies of peripheral nerves, obtained in the advanced stages of the disease, showed severe loss of myelinated fibers and aspects of repeated demyelination and remyelination, with formation of onion bulb complexes. Completely demyelinated axons together with remyelinating fibers as well as remyelinated fibers invested by macrophages were seen at the same time. The clinical and pathological evidences suggest that in chronic relapsing polyneuritis, at least in the late stages of the disease, besides clinical relapses, there is a continuing activity of nerve damage. Thus, due to this ongoing activity of demyelination and remyelination, the elimination of the supernumerary Schwann cells does not take place satisfactorily and hypertrophic changes of the nerve fascicles are produced.

Friedreich's ataxia. A light- and electron microscopic study of peripheral nerve biopsies

Sural or superficial peroneal nerve biopsies of patients with clinical diagnosis of Friedreich's ataxia were studied. Patients were divided in two groups, typical and abortive forms: loss of fibers accompanied by axonal atrophy and segmental demyelination are the basic changes in both groups, although the decrease in number of myelinated fibers was most severe in typical FA. In the cases with slower progression there is a tendency to form onion bulb complexes.

[Effects of graded doses of copper complexes with L-aminoacids on gastric acid secretion in the rat]

Gastric acid responses to intragastric administration of graded doses (14-30-45 mg/Kg) of copper (II) complexes with aminoacids (two simple complexes, Cu-Trp2 and Cu-Phe2, and on mixed complex, Cu-Trp-Phe) were investigated in Shay rats. The results (% inhibition of H+ mEq/4h) shown that graded doses of copper complexes caused a progressive inhibition on gastric acid secretion, and that percentage inhibition values were, for all complexes, in linear correlation with employed doses. A possible mechanism by which copper complexes affect gastric acid secretion is discussed.