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Biomedical subjects

A Colombi

Publications and source records attributed to A Colombi.

At least 55 records · Page 3Linked to original sources
PubMed1983

Liquid chromatography of urinary porphyrins for the biological monitoring of occupational exposure to porphyrinogenic substances.

Very sensitive and precise analytical methods for measuring total porphyrin excretion and the relative amounts of different porphyrins in urine are required in order to monitor the biological effects of porphyrinogenic substances in workers and the general population. Many analytical steps of a HPLC method for measuring porphyrins as methyl esters in urine have been perfected. Sensitivity is 0.1 microgram/1 for each type of porphyrin, and average recovery is 92% in the range of 50-450 micrograms/liter porphyrins. The coefficient of variation is 3.4% within a series and 12.5% between series. Chemical oxidation before analysis and appropriate storing of the samples are the key points in achieving high quality results. The urinary excretion of porphyrins in healthy male workers varies within the range 21 to 161 micrograms/liter (95% limits of a group of 78 subjects). Concomitant factors, like drug use or liver disorders, were found to alter urinary porphyrin excretion. The proposed method permits the detection of extremely small alterations in porphyrin excretion resulting from occupational exposure to industrial chemicals such as, for example, mild coproporphyrinuria or early stages of chemical porphyria induced by polyhalogenated arylhydrocarbons.

Adult↗
PubMed1983

[System of automatic procedures supporting informational functions of the territorial services of occupational medicine].

The article outlines a package of automatic procedures to support the informative needs of the Departments of industrial hygiene. In the first phase these procedures build up a file of the factories and produce a map of the area; in the second phase they manage the team registers, the examination program and the environmental and health statistics; furthermore they are being compatible with the management of the personal data. The system underwent a trial stage in a pilot area.

Computers↗
PubMed1983

[Manual informational procedures for occupational medical services in a transition phase].

An interdisciplinary study group worked out a non-automatic informative procedure for the Services of industrial hygiene, in their present stage of operation. The system provides the census of the factories, the storage of the group data (group registers, sanitary program, environmental and health statistics) and of the individual sheets; the file is organized into several sections. The system is compatible with automatic procedures, which have been adopted by a model-Service.

Computers↗
PubMed1981

Occupational exposure to polychlorinated biphenyls in electrical workers. I. Environmental and blood polychlorinated biphenyls concentrations.

Industrial exposure to polychlorinated biphenyls (PCBs) and internal dose were investigated in 80 worker exposed for many years to PCB mixtures with a 42% chlorine content (Pyralene 3010 and Apirolio). PCBs were determined by liquid gas chromatography on samples taken from workroom air, workroom surfaces and tools, the palms of the hand, and the blood of the workers. In the workroom air samples, PCB concentrations ranged from 48 to 275 micrograms/m3. All tested surfaces and tools were heavily contaminated, with a range from 0.2 to 159 micrograms PCBs per cm2 of surface. Considerable amounts of PCBs were detected on the palms of the hands of the workers (2-28 microgram/cm2 of skin surface). In blood, total PCB concentrations from 88 to 1319 micrograms/kg were observed: comparing the blood concentrations of low and high chlorine content biphenyls, a significant difference was found for the low-chlorinated biphenyl concentrations between workers currently exposed and workers exposed only in the past. In groups of workers who were homogeneous as regards work area and job, the PCB concentrations in the blood were closely correlated with the length of actual occupational exposure to these compounds. These findings led to the conclusion that absorption of PCBs in these workers had occurred mainly through the skin, therefore industrial preventive surveillance must take this route of exposure into account. Since blood PCB concentrations appear to be correlated with the length of exposure, PCB determination on whole blood may be used to monitor industrial and environmental exposure to PCBs.

Adult↗
PubMed1981

Occupational exposure to polychlorinated biphenyls in electrical workers. II. Health effects.

Health conditions were evaluated in 80 electrical workers exposed for many years to polychlorinated biphenyl (PCB) mixtures with a 42% mean chlorine content, who had blood PCB concentrations from 41 to 1319 micrograms/kg. The clinical study was based on personal history data, physical examination, and laboratory tests (red cell and leukocyte count; determination of haemoglobin, packed cell volume, bilirubin, serum protein electrophoretic fractions, pseudocholinesterase, AST, ALT, GGT, and OCT). Fifteen workers were found to have skin diseases--chloracne (4), folliculitis (4), oil dermatitis (1), juvenile acne (1), and dermatitis due to irritative or allergic agents (5). Sixteen workers showed more or less pronounced hepatic involvement, consisting most often of hepatomegaly with an increase in serum GGT, AST, ALT, and OCT values. In two workers bleeding cavernous haemangiomas were discovered, in one case associated with chronic myelocytic leukaemia. All the workers with chloracne were employed on electric capacitor impregnation with PCBs, and no definite association was found between chloracne and blood PCB concentrations. Conversely, a significant positive association was found between the abnormal liver findings and blood PCB concentrations, particularly trichlorobiphenyl blood concentrations. The abnormal hepatic findings observed are similar to those reported in experimental animals given PCBs, and in some workers such findings should probably be considered as clinical signs of hepatic microsomal enzyme induction.

Adult↗
PubMed1981

Carbon disulfide neuropathy in rats. A morphological and ultrastructural study of degeneration and regeneration.

The aim of this study was to elucidate the site and detailed nature of peripheral nerve damage induced in the rat by chronic CS2 inhalation exposure in the light of the relationship between pathological and neurophysiological data. Adult male rats were exposed to 700 ppm of CS2 2 h/d, 5 d/week for 12 weeks and then followed-up for 18 weeks. The first alteration observed was a decrease in the nerve conduction velocity, discovered after only 3 weeks of exposure. Pathological lesions were first observed in the 10th week and consisted of a typical "giant axon" axonopathy. Obvious pathological lesions of the myelin sheaths were revealed much later, in the 3rd week after the end of exposure, when some nerve fibers were dying back. Recovery took place with the regeneration of new fibers which started in the 8th week after the end of exposure and was nearly complete in the 18th week. These findings demonstrate that CS2-induced polyneuropathy is an axonopathy very similar to that caused by other occupational neurotoxic agents like MnBK, n-hexane, and acrylamide. The timing of the pathological events within the nerve fibers suggests that the pathogenesis of the nerve lesions should probably be attributed to a primary energy failure of the axonal membrane induced by CS2.

Animals↗
PubMed1981

Effects of ganglioside therapy on experimental CS2 neuropathy.

Both in animals and in man the inhalation of CS2 vapor induces a chronic polyneuropathy with primary lesions in the axons of peripheral nerves. Since it was reported in several studies that the administration of gangliosides improves nerve regeneration and the functional recovery of nerves damaged by section as well as cryodegeneration, a study was undertaken to evaluate the effects of bovine-brain gangliosides administration on the experimental CS2 neuropathy in the rat. One hundred and fifty male rats were intoxicated with CS2 by a discontinuous inhalation exposure to 700 ppm for 12 weeks until a clear neuropathy developed. Thereafter the animals were subdivided at random into five groups and treated in different ways: 10 mg/kg BW gangliosides, 0.5 mg/kg gangliosides, 0.5 mg/kg vitamin B1, and 1 mg/kg vitamin B6, physiological solution, and controls without any treatment. The recovery from neuropathy was controlled for 18 weeks of treatment and assessed periodically by means of clinical, electromyographic, and morphological examination. The results of morphological studies showed more pronounced regeneration activity in the rats treated with the high dose of gangliosides than in all others, while no differences among the groups could be observed as far as clinical and neurophysiological parameters are concerned. The mechanism supporting this ganglioside-induced effect has so far not been ascertained, and further studies on this subject are in progress.

Animals↗
PubMed1980

[Erythrocyte membrane in Duchenne muscular dystrophy. II. Fluidity of lipids in dystrophic patients and their families].

Electron spin resonance techniques was used to study the fluidity of intact and hemoglobin free erythrocyte membranes from patients with Duchenne muscular distrophy and from members of their family. A greater mobility of spin label motion was observed only at the surface of hemoglobin free membranes in the patients. These studies suggest alterations in lipid-protein interaction, indicating in Duchenne muscular distrophy a generalized membrane abnormality.

Electron Spin Resonance Spectroscopy↗
PubMed1980

[Erythrocyte membrane in Duchenne muscular dystrophy. I. Sensitivity to lysolecithin in dystrophic patients and their families].

The percentage of echinocytes in the blood from patients affected by Duchenne muscular Distrophy was studied after red cells treatment with L-alpha-lysophosphatidylcholine. The echinocyte content was significantly higher in Duchenne patients and in the components of their families, as previously demonstrated is lower in Stainert patients. The sensitivity to lysophosphatidylcholine in Duchenne muscular Distrophy is a diagnostic test for carrier condition

Erythrocyte Membrane↗
PubMed1978

[Partial lipodystrophy and intramembraneous glomerulonephritis].

The case is presented of a young woman with partial lipodystrophy and intramembranous glomerulonephritis. Light and electron microscopic changes in the kidney biopsy are described and discussed. With immunosuppressive therapy very slow progression of the renal insufficiency was observed. Finally, regular dialysis treatment was required to sustain life. The follow-up after detection of intramembranous glomerulonephritis lasted 8 years.

Adult↗
PubMed1978

Electromyographical findings in human chronic Chagas' disease.

An electromyographical investigation of 80 patients with chronic Chagas' disease was made. It was found that 79% of the studied patients had EMG manifestations of old and chronic denervation of the upper and lower limbs without clinical features of nervous system involvement.

Action Potentials↗
PubMed1978

[Bovine graft as arteriovenous fistula for hemodialysis].

We used the bovine carotid artery (BCA) as arteriovenous shunt for hemodialysis in 11 patients since December 1975. We discuss our results. For implantations we used two methods: straight and loop grafts. The BCA have many advantages as: good access for punction, anticoagulation not permanently necessary, volume of shunt more than 250 ml/min; the disadvantages are: increased tendence to infection and thrombosis. Thrombosis in BCA can be easier removed than in other grafts. Reduction of the complications incidence is possible with an accurate technique. We think that the BCA is very useful when Cimino-Brescia fistula has failed or is unavailable; we prefer BCA to a saphenous arteriovenous graft in these situations.

Animals↗