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Biomedical subjects

S Negri

Publications and source records attributed to S Negri.

At least 37 records · Page 2Linked to original sources

[Suprapubic bladder ultrasonography and urinary cytology: indications and limits in the follow-up of superficial bladder tumors].

139 patients underwent urinary cytology and bladder sonography in follow-up of superficial bladder cancer (Ta G1-3) alternatively or at the same time of cystoscopy. Medium follow-up was 27.2 mos. In 7.91% there was progression to T1 o T2 but no case escaped this protocol. In 9% urinary cytology and bladder sonography were both falsely negative: tumors were smaller than 0.5 cm and low grade. In 76 patients with Tar bladder cystoscopy rate was 1/5.2 mos. before this study and 1/7.2 mos. after this study. In our opinion this protocol reveals the recurrence of superficial bladder tumor, reduce cystoscopy rate with no risk of ignored progression.

Carcinoma in Situ↗

The tubulin genes of Trypanosoma cruzi.

The organization of the alpha- and beta-tubulin genes in the genome of Trypanosoma cruzi have been analysed by Southern blotting using tubulin probes derived from Trypanosoma brucei. The tubulin array appears to be more complex in this organism than in other members of the same family. Some tubulin genes are tightly clustered in an alternating (alpha-beta)n array with a basic repeat unit length of 4.3 kb. However, other pairs of alternating alpha- and beta-tubulin sequences appear to be physically separated from the basic group. This finding indicates that the tubulin gene cluster present in T. cruzi is less perfectly conserved than in T. brucei. T. (Herpetosoma) rangeli is similar to T. (Schizotrypanum) cruzi in its tubulin gene organization whereas most of these genes are tandemly clustered in the genome of T. (Trypanozoon) evansi, with a basic repeat unit length of 3.6 kb as previously described for T. (Trypanozoon) brucei. Two overlapping recombinant clones containing T. cruzi tubulin sequences have been isolated from a genomic cosmid library of T. cruzi epimastigotes using the T. brucei tubulin probes. Partial sequencing of the T. cruzi beta-tubulin gene has confirmed its identity and shows more than 70% homology with the sea urchin, chicken and T. b. rhodesiense beta-tubulin reported gene sequences. Analysis of tubulin gene organization through the parasite life cycle does not show evidence of major rearrangements within the repeat unit. Several T. cruzi strains and cloned lines whilst sharing the 4.3-kb tubulin repeat unit, exhibited very variable tubulin gene organization with tubulin probes. These striking differences in the organization of this structural gene among T. cruzi strains and cloned lines suggest that the heterogeneity previously reported in parasite populations may be related to a very dynamic, diploid genome.

Animals↗

Maternal and developmental toxicity of chronic aluminum exposure in mice.

The present study demonstrated aluminum-induced neurotoxicity in mouse dams and developmental retardation in their offspring following oral exposure to several dose levels during gestation and lactation. Female mice fed aluminum lactate (AL) at levels of 500 or 1000 ppm in their diet from Day 0 gestation to Day 21 postpartum were compared to mice which received a 100 ppm aluminum diet either ad libitum or pair-fed to the 1000 ppm AL group. Dams receiving the 500 and 1000 ppm AL diets showed signs of neurotoxicity beginning at Days 12-15 postpartum and showed significant weight loss. Offspring showed dose-dependent decreases in body weight (F = 6.47, p less than 0.001), crown-rump length (F = 7.37, p less than 0.0001), and ponderal index (F = 6.90, p less than 0.0002), at birth and preweaning. Absolute and relative liver and spleen weights were lower in pups from the high AL groups compared to controls (F = 3.34, p less than 0.025 and F = 15.54, p less than 0.001, respectively). Neurobehavioral development was somewhat delayed in aluminum-treated pups, but not in their pair-fed controls (F = 5.52, p less than 0.005). In addition to showing oral toxicity of excess AL during development dose-dependent toxic effects of parenteral aluminum exposure were demonstrated in pregnant mice which were injected subcutaneously with aluminum lactate solution at 10, 20, or 40 mg Al/kg body wt on Days 3, 5, 7, 9, 12, 13, and 15 of gestation. Maternal spleen and liver weights were significantly increased in aluminum treated animals (p less than 0.001 and p less than 0.05, respectively). Fetal crown-rump lengths were significantly reduced in the 20 mg/kg aluminum group (F = 9.79, p less than 0.001).

Administration, Oral↗

[Esophageal localization of granulosa cell tumor (presentation of a clinical case)].

The authors report on a case of granular cell tumour localized in the lower third of the thoracic oesophagus. The patient, a 49-year-old male, suffering from symptoms of dysphagia over the previous few months, was treated surgically by thoracotomy enucleation of the neoplasm. Despite its slow growth, this rare benign neoplasm, which probably originates in Schwann's sheath, is a candidate for endoscopic or surgical resection.

Diagnosis, Differential↗

Trypanosoma cruzi: polypeptide markers of epimastigotes and trypomastigotes.

We compared the major polypeptides of epimastigotes and trypomastigotes of T. cruzi, by submitting total parasite lysates to electrophoresis in polyacrylamide gels (SDS-PAGE), protein staining with Coomassie brilliant blue, laser densitometry, or immunoblotting with sera derived from infected individuals (Chagas' disease). Epimastigotes and trypomastigotes displayed extensive homology, the differences being quantitative, except for a trypomastigote-specific band of Mr 75,000 which reacted with chagasic sera. Immunoblotting with chagasic sera confirmed the electrophoretic homology of epimastigotes and trypomastigotes. Upon antigenic dilution, a cluster of antigenic bands in the range of Mr 150,000 to 75,000 prevailed in the trypomastigotes, whereas the epimastigotes displayed more abundance of antigenic bands in the range of Mr 72,000 to 36,000.

Animals↗

Electromyography and nerve conduction study in autosomal dominant olivopontocerebellar atrophy.

Electromyographic examination and studies of motor and sensory conduction velocities were performed in 11 patients with a presumptive diagnosis of olivopontocerebellar atrophy with autosomal dominant transmission. Peripheral nervous system involvement was shown in eight. In two patients with early onset of disease, electrophysiological alterations clearly pointed to severe axonal degeneration, whereas in six they were compatible with slight demyelination.

Action Potentials↗

Changes in morphology and infectivity of cell culture-derived trypomastigotes of Trypanosoma cruzi.

Trypomastigotes of Trypanosoma cruzi, obtained from the first burst of infected Vero cells, have only a limited invasive capability for fibroblastic cells. Intracellular amastigotes and epimastigotes do not infect these cells at all. Preincubation of the isolated trypomastigotes with Eagle's minimal essential medium/10% fetal calf serum increases 5- to 15-fold their in vitro infectivity. This increased invasive capability is accompanied, in the case of the EP strain of T. cruzi, by a morphological transformation into an amastigote-like or spheromastigote form, which is similar, but not identical to replicating intracellular amastigotes. Trypomastigotes from another isolate (BEC) also increase their infectivity several fold upon preincubation, but before any morphological differentiation occurs, suggesting that these two events are independent. The phenomenon of increased infective capability of the parasite is expressed similarly in different host cells. Parasite adhesion is stimulated 4- to 12-fold upon preincubation of the trypomastigotes. The type of serum used (fetal calf, calf, human) affects the development of infectivity, as well as the process of cell infection in itself, but not the morphological differentiation. These processes are also temperature-dependent. The highly infective parasitic forms do not synthetize DNA, but are active in RNA and protein synthesis. The results obtained indicate the existence in T. cruzi trypomastigotes of an active system for infecting fibroblastic cells, which is only partially expressed in trypomastigotes recently released from host fibroblasts but which can undergo a further extracellular maturation, thus allowing studies on the mechanism of infection in cell-free media.

Animals↗

Systemic carnitine deficiency with peripheral nerve involvement morphological and biochemical study.

The patient, a 31-year-old woman, suffered from a weakness of the proximal muscles which subsequently worsened involving the spinal and neck muscles. During the hospitalization, the patient displayed a "burning feet" syndrome. Lab tests showed a moderate increase in CPK, Aldolase, SGPT, SGOT, lactic and pyruvic acids. Needle EMG was interpreted as "myopathic" but a marked reduction of sensitive action potentials was also detected. Muscle biopsy showed neutral lipid accumulation in muscle fibers, many small angular fibers, probably denervated ones were also evident. A liver biopsy showed fatty accumulation in hepatocytes. Free carnitine was extremely reduced in muscle and liver and just below normal level in plasma while there was a tenfold elevation of long-chain carnitine esters in plasma too. The mechanism by which carnitine deficiency can cause both neural and muscular alterations and in particular the role of carnitine in glucose metabolism is discussed.

Adult↗

5-OH-Tryptophane in migraine: clinical and neurophysiological considerations.

The clinical effects of the protracted treatment with 5-OH Tryptophane (5-HTP) of some patients with chronic migraine are compared with other patients with acetylsalicylic acid. The pain threshold was neurophysiologically determined in migraneous on patients whose response to 5-HTP therapy was specially good. The results with 5-HTP can be accounted for by an action of the substance on the serotonin turnover with activation of the serotoninergic antinociceptive system.

5-Hydroxytryptophan↗

Neurological and pharmacological evaluation of a case of stiff-man syndrome.

A typical case of stiff-man syndrome was studied neurophysiologically and pharmacologically focusing the attention on a central disorder, either spinal or suprasegmental. The results support the hypothesis that a gamma type of hypertonia is one of the causes of the stiff-man syndrome, ruling out the participation of the Renshaw circuits. The syndrome should be considered a central disorder of the descending pathways that control and modify gamma activity and the startle reaction mechanisms, especially affecting the circuits that use Gabaergic mediators.

Adult↗

Friedreich's ataxia. I. Clinical, neurophysiological and in vivo biochemical studies.

Eighteen patients with the presumptive diagnosis of Friedreich's ataxia were studied. Clinical, neurophysiological and biochemical data were concordant in 14 patients and led to the diagnosis of typical Friedreich's ataxia in this group of patients: the remaining 4 patients differed from the typical patients in several respects but mainly in the cardiological findings. It is concluded that so far no single clinical or laboratory finding is typical of F.A.. Multidisciplinary approaches are essential to the diagnosis of Friedreich's ataxia.

Adolescent↗

Effect of L-5HTP and drugs acting on serotonin metabolism in various myoclonic syndromes.

Ten patients affected by various myoclonic syndromes were tested with drugs acting on cerebral serotonin metabolism and with clonazepam (CZP). After L5HTP or serotonergic drugs administration a clear cut improvement was observed in the 2 patients affected by Ramsay-Hunt syndrome, while the patients with myoclonic epilepsy have shown no effect (3 cases) or negative response (1 case). Methysergide was active only in 1 patient affected by progressive erratic myoclonus who had a striking worsening of clinical picture. The main side effects observed were: gastrointestinal distress (L5HTP--4 patients, fenfluoramine--2, quipazine--1, methysergide--2) and cutaneous rash (quipazine--1 case). These results support the possible implication of the serotonergic system in the pathogenesis of myoclonus other than post-anoxic.

5-Hydroxytryptophan↗

Alternating myasthenia and myastheniform syndrome in the same subject.

A man of 23 years was affected by myasthenia with amyotrophic patterns. From the neurophysiological viewpoint, there were typical electrophysiological aspects of myasthenia gravis and the Eaton-Lambert syndrome simultaneously. In some instances the various electrophysiological tests were preceeded by the administration of Tensilon, calcium gluconate and sodium benzoate caffeine. It is hypothesized that there are two types of endplates present, or there is a functional variability by which at different moments a block results from a defect in the formation or liberation of acetylcholine.

Acetylcholine↗

Alterations of ocular motility in cerebellar pathology. An electro-oculographic study.

Saccadic as well as smooth pursuit movements were studied by means of electro-oculograms in a group of 14 patients affected by cerebellar diseases. Ten patients had cerebellar atrophies, and four had undergone surgery for cerebellar tumors. Loss of gain of the pursuit system and metric alteration of saccades were the most striking abnormalities observed. Dysmetria was shown to be related to the amplitude of the movement and to the sector of the perimeter within which the movement occurs (movements occurring in the more eccentric sector were more disturbed). A tendency to produce saccades slower than normal was noted in patients affected by olivopontocerebellar atrophy. The clinical and pathophysiological significance of this finding is discussed with particular reference to Wadia-Swaami hereditary ataxia.

Adult↗