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Biomedical subjects

L Santoro

Publications and source records attributed to L Santoro.

At least 145 records · Page 8Linked to original sources
PubMed1986

Is the sensory neuropathy in ataxia-telangiectasia distinguishable from that in Friedreich's ataxia? Morphometric and ultrastructural study of the sural nerve in a case of Louis Bar syndrome.

The bioptical morphometric and ultrastructural study of sural nerve in a 17-year-old boy with ataxia-telangiectasia (AT) is reported. Our findings include a loss of fibers, particularly of large ones, axonal degenerative changes, Schwann cell inclusions of various type, and rare signs of primary demyelination. Teased-fiber study showed paranodal myelin enlargements, segmental demyelination, shortening, and/or variability of internodal length. This picture is similar to that in Friedreich's ataxia (FA), although they differ in degree and time of onset. A correct neuropathologic diagnosis of AT cannot be made on the basis of sural nerve biopsy alone.

Adolescent↗
PubMed1986

The oxidation of cyclothionine by D-aspartate oxidase.

Cyclothionine was found to be a substrate for bovine kidney D-Aspartate oxidase. The substrate, prepared chemically as a mixture of the possible stereoisomers, exhibits an inhibition at elevated concentrations. Compounds structurally related to cyclothionine, like TMDA and alpha-alpha'-iminodipropionic acid, have also been assayed with the enzyme.

Amino Acid Oxidoreductases↗
PubMed1985

Lymphoid stroma of Warthin's tumor: phenotypic analogies with gut-associated lymphoid tissue.

Lymphocytes in cell suspensions and cryostat sections of Warthin's tumors (WT) have been phenotypically characterized using a battery of monoclonal and polyclonal antisera to lymphoid cell-associated antigens. The present study shows that in the WT lymphoid stroma, B cells are more numerous than T lymphocytes and include a significant percentage of surface immunoglobulin A-bearing cells. Of the T cells, the Leu 3a+ and OKT4+ lymphocytes are present in higher percentages than the OKT8+ ones. Both T-cell subsets present a topographic distribution which is similar to that found in human tonsils and gut tunica propria. Intraepithelial lymphocytes displaying an OKT8+, Leu 3a-, OKT3- phenotype are also present. These data, together with previous findings which have demonstrated that Warthin's tumor epithelium synthesizes IgA secretory piece, suggest that these cells may modulate the organization of the surrounding lymphoid stroma toward that of a mature lymphatic tissue phenotipically resembling gut-associated lymphoid tissue.

Adenolymphoma↗
PubMed1984

Specific impairment of BAER's in Friedreich's ataxia. Auditory evoked responses in clinical evaluation and differential diagnosis.

We have investigated brainstem and cortical auditory responses (BAERs and CAERs) in 16 cases of Friedreich's ataxia (FA) and have compared the findings with those obtained in 2 cases of familial spastic paraplegia (FSP), in 5 cases of Charcot-Marie-Tooth disease (CMTD), and in 6 cases of atypical FA of uncertain classification. BAERs could not be elicited in 11 FA patients and constantly disappeared at a higher intensity threshold than in normal subjects in the remaining 5 patients. BAERs were normal or only slightly abnormal in FSP and CMTD patients. CAERs were normal in all 29 patients. BAERs tended to disappear with the progression of FA and BAER thresholds were correlated with the Inherited Ataxias Clinical Rating Scale score, which is an index of the severity of illness. BAERs contributed to the diagnosis, or exclusion of FA in patients with an atypical picture. It is suggested that in FA myelinated fibers in the spiral ganglion are partially affected, resulting in the decrease of wave amplitude such as occurs for peripheral sensory potentials.

Adolescent↗
PubMed1984

Evidence that Charcot-Marie-tooth disease with tremor coincides with the Roussy-Levy syndrome.

We report data on 3 members of a family affected by a dominantly inherited disorder closely resembling Roussy-Levy syndrome (RLS). Electrophysiological findings showed a marked decrease of motor and sensory conduction velocities and EMG signs of mild neurogenic damage. Light and electron microscopy of sural nerve biopsy showed a hypertrophic neuropathy with diffuse onion-bulb formations and marked decrease of large size fibers. Teased fiber preparations evidenced reduced internodal lengths and segmental demyelination. Other data from the literature on RLS are reviewed and discussed. The hypothesis that RLS is not a disease entity but a hypertrophic-type of Charcot-Marie-Tooth disease with essential tremor (HMSN type 1) is strongly supported.

Adult↗
PubMed1983

Similarity of the oxidation products of L-cystathionine by L-amino acid oxidase to those excreted by cystathioninuric patients.

L-Cystathionine is oxidized by snake venom L-amino acid oxidase at a rate about half that with L-leucine at pH 8.5. The appearance of an absorbance at 296 nm and quantitation of the products of oxidation in the presence of catalase indicate formation in the solutions of a seven-membered ketimine ring produced by cyclization of the monoamino monoketo derivative of cystathionine. A limited double deamination has also been observed. In the absence of catalase, S-(carboxymethyl)homocysteine and S-(beta-carboxyethyl)cysteine have been identified together with ninhydrin-unreactive compounds yielding the above mentioned carboxy compounds upon hydrolysis with HCl. Authentic samples of the monoamino monoketo analogs of cystathionine have been prepared and compared with the enzymatic products. Cyclization of the synthetic products into the ketimine ring is pH-dependent as established by UV spectrum and other assays. Compounds derived from either the oxidation or the reduction of the ketimine have been prepared. It was found that many products of enzymatic and chemical changes of cystathionine and its ketimine described in the present paper are identical with those identified in the urine of cystathioninuric patients. This result indicates the occurrence in humans of secondary metabolic routes of cystathionine centered on the production of cystathionine ketimine, in equilibrium with the open form, which in cystathioninurics is revealed by the lack of cystathionase.

Amino Acid Metabolism, Inborn Errors↗
PubMed1983

Median-ulnar nerve communications: electrophysiological demonstration of motor and sensory fibre cross-over.

In a 33-year-old female with carpal tunnel syndrome the presence of anomalous communications between median and ulnar nerves was electrophysiologically demonstrated in the forearm. Motor latencies from proximal and distal stimulation sites along the median nerve fibres to the abductor pollicis brevis were identical. Proximal latency "increased" after procaine infiltration of the ulnar nerve at the wrist. Normal latency to the abductor digiti minimi was obtained on stimulation of the median nerve at the elbow. Along the sensory fibres of the median nerve orthodromic conduction velocity was markedly slowed from digit III to the wrist and normal from the wrist to the elbow. On supramaximal stimulation of digit III a sensory response was also recorded from the ulnar nerve at the wrist. On stimulation of digit V a sensory potential was recorded from the median nerve at the elbow. This appears to be the first electrophysiological demonstration of an anomaly involving both the motor and sensory fibres of both the median and the ulnar nerves.

Adult↗
PubMed1983

Friedreich's ataxia: electrophysiological and histological findings.

Electromyography was performed, and motor and sensory nerve conduction velocities were measured in 19 patients definitely affected by Friedreich's ataxia. Biopsy of the sural nerve was also performed in 9 patients. Most patients presented a moderate to severe loss of motor units, a significant increase in mean duration of motor unit potentials, and in the incidence of polyphasic potentials. Short-lasting spontaneous activity was rarely seen. Conduction velocity along the motor and sensory fibres of the median and tibial nerves was moderately slowed, while distal conduction time to muscle was significantly increased and the sensory orthodromically-evoked response markedly reduced. Intraoperative electrophysiological recordings obtained during biopsy of the sural nerve in 4 patients were consistent with the changes conventionally observed in the median, tibial and sural (6 patients) nerves. Quantitative histology revealed a reduced number of total myelinated fibres with a severe loss of large fibres, and a moderate loss of fibres of less than 7 microns in diameter. In teased nerve fibre preparations, the most evident abnormality consisted of fibres with uniformly short internodal length, while signs of remyelination were less prominent. Signs of active axonal degeneration were rarely observed in electron microscopy. Electrophysiological and histological findings were uniformly distributed, and the changes were neither related to the duration nor to the severity of the clinical condition.

Adolescent↗
PubMed1983

Histochemical study of glycogen and phosphorylase activity on bilateral biopsies of oligospermic men with varicocele.

Varicocele is responsible for a high percentage of impairment of spermatogenesis. In contrast to the normal human testis, Sertoli cell glycogen is reduced, while the reaction product of phosphorylase is considerably increased. Even if the mechanism by which varicocele produces deleterious effects on male fertility remains obscure, an anomaly in glycogen metabolism appears to be present bilaterally in impaired spermatogenesis due to the varicocele.

Glycogen↗
PubMed1981

Impaired insulin secretion in human diabetes mellitus III. The effect of the serotonin antagonist metergoline.

The present study was aimed at investigating the effect of metergoline, a powerful and long-lasting antiserotoninergic agent, on insulin responses to glucose and arginine in adult-onset diabetic subjects. The repeated administration of this agent (10 mg daily for two days plus a 4 mg dose 1 hour before the post-treatment test) or placebo did not influence acute insulin response to intravenous glucose (20 g), total insulin secretion or glucose disappearance rates. Similarly, plasma glucose and insulin levels following arginine (30 g perfused over a period of 40 min) were similar before and after metergoline treatment. These results do not support the hypothesis that an endogenous monoamine mechanism plays an important part in defective insulin secretion in human non insulin-dependent diabetes mellitus.

Adult↗