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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
PubMed1985

[Analysis of electroneurographic data on a sample of normal subjects].

The ENGraphic basic data of 41 normal subjects were measured to determine a range of normal values and to analyze the importance of individual factors (gender, age, work). The work affects significantly the conduction velocities and the latencies more frequently than gender and age.

Adolescent↗
PubMed1984

[New diagnostic and therapeutic aspects of acute kidney failure].

In a 20 months' period 20 patients were dialyzed at the Cantonal Hospital, Lucerne, because of acute renal failure (ARF). Contrary to expectation, the main cause was not circulatory failure but traumatic and nontraumatic rhabdomyolysis (5 patients), septicemia (9 patients) and endogenous and exogenous intoxications. In only 2 patients did shock seem an important factor in the pathogenesis of ARF. In view of the many causes of rhabdomyolysis, the frequency of patients with myoglobinuric ARF is hardly surprising. Case history, brown-colored urine with a positive reaction for hemoglobin in the absence of significant hematuria and without significant hemolysis (as judged by the color of the plasma or serum) and, most important, high creatine kinase (10(4) to 10(6) U/l) point to the correct diagnosis. In patients who had undergone trauma or surgery the main cause of ARF was uncontrollable infection. A long interval between the accident or operation and the onset of ARF was typical in these cases. Both hemodialysis and peritoneal dialysis are adequate methods of treatment for ARF. For technical reasons, however, in more than 50% of patients with ARF due to trauma or surgery, peritoneal dialysis is not feasible. On the other hand, in patients with cardiovascular instability continuous arterio-venous hemofiltration serves as an alternative to hemodialysis. With the introduction of Y-shaped dialysis catheters and the single needle system with double pump and controlled ultrafiltration, hemodialysis has become an easier and safer procedure. For patients with prolonged-course ARF the authors prefer a combination of initial hemodialysis, followed by peritoneal dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1984

The speciation of the chemical forms of arsenic in the biological monitoring of exposure to inorganic arsenic.

Total As content may be determined in blood and urine by means of an AAS method that involves reduction of As to its volatile hydride and ashing at 600 degrees C with MgO and Mg (NO3)2. Separation of inorganic As (InAs), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMAA) by ion-exchange chromatography, followed by direct AAS analysis, allows the determination of each As species in the urine. In a reference population of 148 subjects with only normal environmental exposure to As, total As concentration in the urine averages 17.2 +/- 11.1 micrograms/l. Urinary As consists of 10% each of InAs, MMAA and DMAA, the remaining 70% consisting of other forms of organic As. Blood As concentration averages 5.1 +/- 6.9 micrograms/l and correlates significantly with the urinary concentration of InAs and the sum of its metabolites (InAs + MMAA + DMAA). Inorganic arsenic undergoes methylation in the organism. After ingestion of high quantities of As2O3, the time course of excretion of its metabolites indicates that As methylation occurs by a saturable mechanism. In workers exposed to As2O3, InAs, MMAA and DMAA are the only chemical forms of As excreted in the urine that are relevant to a study of occupational exposure. Blood As concentration is proportional to exposure and correlates only with urinary DMAA excretion; DMAA seems to be the most appropriate single indicator of exposure. At high levels of exposure (total As excretion above 200 micrograms/l), As accumulates in the organism and DMAA excretion reflects its accumulation. At low levels of exposure (total As excretion below 50 micrograms/l) a short-term accumulation does not occur and the best biological indicator of exposure is InAs excretion. Seafood ingestion brings about a marked increase in urinary excretion of total As that lasts for 24-48 h and is not accompanied by any increase in InAs, MMAA or DMAA excretion. Organic As from seafood does not mix with the pool of inorganic As in the organism and may be separately detected in urine. In the biological monitoring of human exposure to As, particularly in the case of high urinary values, the speciation of the chemical forms of As in urine is necessary in order to establish with certainty the source, industrial or alimentary, of exposure.

Arsenic↗
PubMed1984

Significance of arsenic metabolic forms in urine. Part I: Chemical speciation.

The aim of this research has been to develop analytical procedures whereby the various chemical forms of arsenic present in urine can be distinguished and further data on the biotransformation of absorbed arsenic can be acquired. The separation of inorganic arsenic ( InAs ), monomethylarsonic acid ( MMAA ), and dimethylarsinic acid ( DMAA ) in urine was performed by ion-exchange chromatography on AG 50 W-X8 resin. Arsenic was then measured directly on the eluted fractions by atomic absorption spectrophotometry, after the reduction of arsenic to the correspondent arsine. In 160 subjects with no occupational exposure to arsenic compounds, InAs , MMAA , DMAA each accounted for about 10% of the total arsenic urinary excretion (17.2 +/- 11.1 micrograms/1), thus indicating that in the normal population over 60% of arsenic in urine is present in other organic forms. After eating marine food, there was a marked increase of urinary output of arsenic, but no increase was observed in InAs , MMAA and DMAA urinary excretion. In the biological monitoring of exposure to inorganic arsenic, particularly in the case of high urinary excretion values, the differentiation of the excreted forms of arsenic is necessary to establish with certainty the source (industrial or alimentary) of arsenic.

Adult↗
PubMed1983

Low-pH method for the enzymatic assay of D-glucaric acid in urine.

The enzymatic methods for measuring D-glucaric acid in urine are based on the conversion of D-glucaric acid into its 1,4-lactone and measurement of inhibition of 1,4-lactone against beta-glucuronidase at pH 5.0. All the enzymatic methods described suffer from the disadvantage of a procedure that is complicated and inherently inaccurate, because the nature of glucaric acid/1,4-lactone equilibrium has not been properly considered in the development of such methods. After elucidating the factors influencing glucaric acid/1,4 lactone equilibrium in more detail, a low-pH enzymatic method has been developed in which the 1,4-lactone is formed in the urine sample by acid boiling at pH 3.8 and assayed at the same pH using beta-glucuronidase from Limpets. This procedure allows the acid/lactone equilibrium to remain stable during both the lactonization step and the enzymatic assay. The coefficient of variation for the proposed method (within-run and between-day precision) was from 4.2 to 8.7. The analytical recovery varied from 92-108%.

Glucaric Acid↗
PubMed1983

Influence of sex, age, and smoking habits on the urinary excretion of D-glucaric acid.

Reference values for urinary D-glucaric acid and the influence of sex, age and smoking habits were evaluated with a low-pH enzymatic method. D-Glucaric acid measured on spot urine samples from 573 healthy subjects gave mean concentrations (mumol/1) and D-glucaric acid/creatinine ratios (mmol/mol creatinine) of 56.1 (+/- 22.9) and 3.05 (+/- 0.99) for males and 53.3 (+/- 20.9) and 3.35 (+/- 0.95) for females. No difference between morning and evening was observed for urinary D-glucaric acid/1 values, but D-glucaric acid/creatinine was higher in the evening samples for both sexes. There was a negative correlation between D-glucaric acid/1 values and age in males but not in females: the decrease of D-glucaric acid concentration was, however, quantitatively very small. Smoking produced a significant increase in D-glucaric acid concentration and in the D-glucaric acid/creatinine ratio for males and also partially for females.

Adolescent↗
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↗