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Biomedical subjects

K Lindström

Publications and source records attributed to K Lindström.

At least 145 records · Page 8Linked to original sources
PubMed1982

Exposure limits and medical surveillance in occupational health.

The standards for pollutants in workplace air constitute a social consensus or agreement about acceptable levels of occupational hygiene. This agreement to exposures up to these limits inevitably includes a finite risk to the health of the workers. The numeric values of standards are needed to assess the requirements for ventilation and other occupational hygiene conditions. Planning and everyday practice in industry also need hygienic standards so that practical hygienic and safety measures can be maintained. These standards are not, however, levels below which there is no risk to health. While the hygienic standard itself carries acceptance of a certain risk, doctors cannot ethically accept any health risk to workers whatever the source of exposure. Thus personnel working in occupational health have to think about the risks of ill health even when the hygienic standards are met. The physician in occupational health has to be especially concerned to discover and estimate the risks to anyone particularly susceptible to exposures within the hygienically acceptable conditions. To do this, the occupational health physician uses medical examinations and specific investigations. In the follow-up of workers, health occupational health personnel use medical examinations in order to detect possible risks or to assess the general health status of individual workers. Health examinations are also used to detect specific injuries caused by the agents to which workers are known to be exposed in their work.

Carcinogens↗
PubMed1982

Adenosine receptors mediating cyclic AMP production in the rat hippocampus.

In the transversely cut rat hippocampus, adenosine caused a dose-dependent increase in the accumulation of [3H]cyclic AMP from [3H]ATP. Adenosine breakdown products were inactive. AMP was somewhat less effective than adenosine, and its effect could be partially, but not completely, abolished by alpha, beta-methylene-ADP and GMP, which inhibited its metabolism by 5'-nucleotidase. The effect of adenosine was unaffected by inhibitors of adenosine deaminase, but enhanced by several inhibitors of adenosine uptake. Some analogues of adenosine, including N6-phenylisopropyladenosine (PIA), 2-chloroadenosine and adenosine 5'-ethylcarboxamide (NECA), were more active than adenosine, whereas others such as 2-deoxyadenosine and 9-(tetrahydro-2-furyl)adenine (SQ 22536) actually inhibited the response. The effect of PIA was highly stereospecific. The action of adenosine was inhibited by several alkylxanthines, the most potent of which was 8-phenyltheophylline. [3H]Cyclohexyladenosine (CHA) bound specifically to cell membranes from the rat hippocampus. The extent of binding was similar to that found in other cortical areas. The relative potency of some adenosine analogues and alkylxanthines to displace labelled CHA was essentially similar to their potency as effectors of the cyclic AMP system. Adenosine contributed to the cyclic AMP-elevating effect of alpha-adrenoceptor-stimulating drugs and several amino acids, but not to that seen with isoprenaline. The cyclic AMP increase seen following depolarization was only partially adenosine-dependent. The present results demonstrate that the rat hippocampus contains adenosine receptors mediating cyclic AMP accumulation and that these receptors have similar characteristics to those mediating pyramidal cell depression. Adenosine-induced cyclic AMP accumulation may be used as a biochemical correlate to electrophysiology and as a convenient parameter to assess the influence of drugs on adenosine mechanisms in the rat hippocampus.

Adenosine↗
PubMed1982

Ultrasound assessment of liver veins in congestive heart failure.

The width of the liver veins was measured using ultrasound in 40 normal subjects and in 29 patients with congestive heart failure with and without pleural effusion. The liver veins were significantly wider in the patients, and the widest veins were found in those with pleural effusion. The presence of pleural effusion indicates that right heart failure, causing dilatation of liver veins, is added to pre-existing left heart failure.

Aged↗
PubMed1982

Behavioral effects of long-term exposure to organic solvents.

Epidemiological studies have detected an increased risk of neuropsychiatric diseases among groups occupationally exposed to organic solvents. Psychological studies of solvent exposed workers have investigated both cognitive and sensory and motors functions. Most of these studies have dealt with trichloroethylene, toluene, styrene, and mixtures of organic solvents. Most of these studies have found a decline in the sensory and motor functions. Of the cognitive functions especially short-term memory has proved to be sensitive to solvent exposure. Also some implications of declined visuoconstructive abilities have been found. It has been possible to analyze exposure-response and exposure-effect relationships between exposure and psychological findings only for some single studies, because reliable measures for long-term solvent exposure have usually not been available. The measurement of personality characteristics among solvent exposure workers has been another neglected area.

Behavior↗
PubMed1982

Neurophysiological findings among house painters exposed to solvents.

Seventy-two male house painters in maintenance work (aged from 35 to 44 a) with a mean of 20.2 a of painting experience were submitted to electroencephalographic (EEG) and electroneurographic examinations; 77 concrete reinforcement workers of similar ages served as the referents. The average long-term exposure level of the painters corresponded to 40 cm3/m3 of white spirit. Altogether six motor conduction velocities and seven sensory conduction velocities were measured for each subject. The frequency of abnormal EEGs among the painters was similar to that found for a normal population or for the referents, namely, 15% of the painters showed a mild and 1% a moderately severe EEG abnormality. The means of the nerve conduction velocities were similar among the painters and referents and also close to the means of the normal material of the laboratory. Slightly slowed nerve conduction velocities suggestive of peripheral nerve dysfunction were found in 20% of both the painters and the referents. This exposure level did not affect the EEG noticeably. A few subjects with abnormally slow nerve conduction velocities may have been affected by occupational factors, either chemical or physical, but the solvent-exposed workers did not differ from their referents in this regard.

Adult↗
PubMed1981

Behavioral changes after long-term exposure to organic solvents and their mixtures: determining factors and research results.

This presentation summarizes the characteristics determining the psychological end state after long-term solvent exposure. It also presents the results of research on changes in psychological functions after long-term solvent exposure. Such factors as differential vulnerability and environmental influences other than solvent exposure at work and elsewhere affect the end state. The results of five different Finnish studies are summarized. These studies concerned workers with solvent poisoning, car painters exposed to solvent mixtures, rayon viscose workers exposed to carbon disulfide, printers exposed to toluene, and laminators exposed to styrene. Intellectual functions, short-term memory, and sensory and motor functions were inspected. Verbal intelligence was lowered only in cases of intoxication and exposure to mixtures of organic solvents. Visuoconstructive abilities were deteriorated in those groups with verbal intelligence deterioration, and also among both rayon viscose workers with solvent poisoning and car painters. The group exposed to styrene showed functional changes only in visuomotor accuracy. Lowered manual or finger dexterity was found among workers exposed to carbon disulfide, workers with solvent poisoning, and car painters. The most disturbances were accumulated among those exposed to mixtures of organic solvents.

Adult↗
PubMed1980

Neurophysiological and psychological picture of solvent poisoning.

Neurophysiological and psychological tests were administered to 107 patients--48 men and 59 women--with a diagnosis of solvent poisoning after longstanding (mean 9.6 years for males and mean 7.6 years for females) occupational exposure. Electroencephalography (EEG) and a wide psychological test battery were applied in all cases, and electroneurographic measurements were performed in 77 subjects. Sixty-five percent of the patients showed an abnormal EEG, and excessive beta activity, not induced by drugs, was found in 54% of patients. At least one abnormally slow nerve conduction velocity (CV) was found in 48 out of 77 patients. The scores of Wechsler Adult Intelligence Scale (WAIS) subtests Digit Span (DSp) and Digit Symbol (DSy) among the men and scores of Similarities (Sim), Digit Symbol (DSy), Picture Completion (PC), and Block Design (BD) among the women were statistically significantly lower than in the Finnish standardization sample. Long duration of exposure was related to poor performance in the Santa Ana Dexterity test in both sexes, to poor visual memory among the men and to poor visuoconstructive intellectual tasks among the women. The background frequency in the EEG showed a correlation to the DSp test of WAIS and some relationship emerged also between the former and the BD, the Symmetry Drawing test, the Santa Ana Dexterity test, and the Mira test. Focal slow wave abnormalities were related to inaccurate hand movements in the psychomotor Mira test. Neurophysiological and psychological tests seem to reflect partly different aspects of neurologic effects and their combined use helps in the evaluation of hazards of solvent exposure.

Adult↗
PubMed1980

Changes in psychological performances of solvent-poisoned and solvent-exposed workers.

The changes in psychological performances associated with long-term exposure to organic solvents and solvent mixtures were studied in a group of 56 male workers diagnosed as having an occupational disease caused by solvents. Their mean duration of exposure was 9.1 +/- SD 8.3 years, and they were exposed mainly to halogenated and aromatic hydrocarbons and to mixtures of paint solvents. The psychological performances of these solvent-exposed patients were compared with those of 98 styrene-exposed workers and a nonexposed group of 43 construction workers. The applied psychological test variables were factor analyzed, before other statistical analysis, in order to clarify what they measured in the present study. The solvent-exposed group was characterized by a decline in visuomotor performance and decreased freedom from distractibility. The poor visuomotor performances were also related to the long duration of solvent exposure in this group of patients. The index applied for the exposure level revealed no significant relationships to psychological performances among the solvent-exposed patients. The psychological performances of the styrene-exposed group differed only very slightly from those of the nonexposed workers.

Adult↗
PubMed1980

Personality and long term exposure to organic solvents.

Personality, especially emotional reactions of two solvent exposed groups and a nonexposed reference group were described by means of 20 formal, content and check-list type of Rorschach variables. Another objective of the study was to explore the suitability and psychological meaning of other types of Rorschach variables than those applied earlier in the field of behavioral toxicology. The factor analyses grouped the applied variables into factors of Productivity, Ego Strength, Control of Emotionality, Defensive Introversion and Aggressiveness. One solvent group, a patient groups (N=53), was characterized by a high number of Organic signs and a low Genetic Level, indicating possible psychoorganic deterioration. The other solvent group, styrene exposed but subjectively healthy (N=98), was characterized by few emotional reactions, low Anxiety and a low number of Neurotic Signs. the long duration of exposure of the solvent patient group (mean 10.2 +/- 8.7 years) was related to variables of the Productivity factor, a finding that indicates a possible better adjustment of those exposed for a longer time. The duration of exposure of the styrene exposed group (mean 4.9 +/- 3.2 years) revealed a very slight relation to personality variables, but the mean urinary mandelic acid concentration, indicating the level of styrene exposure, correlated with increased emotional reactions. For the most part definite causal conclusions could not be drawn because of the cross-sectional design of the study.

Adult↗
PubMed1979

Determination of myometrial tension during labor by combined microtransducer IUP-rcording and ultrasonic examination of the uterine cavity.

In twelve women, in whom labor was induced by oxytocin infusion, intra-uterine pressure (IUP) was recorded by micro-transducers, and simultaneously the diameter of the uterine cavity was estimated by means of ultrasound. Myometrial tension was calculated according to the law of Laplace. In the ten women who were delivered within eight hours after the start of induction, myometrial tension was clearly higher than in the two in whom induction failed. No technical problems were encountered during the registrations, which in some cases lasted for more than five hours. It is suggested that with the described technique, a more accurate determination of myometrial activity is possible than with the generally used methods for IUP recording. The technique might facilitate evaluation of drug effects on the uterus during labor, and improve the IUP-part of intrapartum clinical monitors.

Adult↗
PubMed1979

Heart synchronized gamma - camera gating: displaying two heart cycles on one screen.

A method for the evaluation of the haemodynamic status of a patient with acute myocardial infarction is presented. Left ventricular ejection fraction has been considered to be an accurate indicator of haemodynamic status before and after therapy. A device for synchronising the R-wave, and controlling the recording oscilloscope during systole and diastole is described. The intention is to display both systole and diastole on one oscilloscope.

Cardiac Volume↗
PubMed1979

The mechanism of lysine-vasopressin hemostasis in bleeding esophageal varices.

The effect of vasopressin on the blood flow through experimentally induced esophageal varices and on the musculature of the lower end of the esophagus has been studied. The blood flow was measured by 85Kr injection into the portal vein and selective recording of the radioactivity of the blood flow through the varices. Simultaneous portography and recording of the portal and arterial blood pressure were performed. Following i.v. administration of vasopressin, there was seen a decrease in portal pressure and transient increase in arterial blood pressure. Simultaneously there was observed a decrease in blood flow through the varices, which were no longer visible at portography, while intra-esophageal pressure was increased. It is concluded that there is a dual mechanism of the effect of vasopressin on bleeding from esophageal varices. It reduces the portal pressure and it contracts the esophageal musculature with resultant compression of the afferent radicles to the submucosal esophageal varices.

Animals↗