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Biomedical subjects

K Rossi

Publications and source records attributed to K Rossi.

At least 19 recordsLinked to original sources
PubMed2001

A genetic model provides evidence that the receptor for atrial natriuretic peptide (guanylyl cyclase-A) inhibits cardiac ventricular myocyte hypertrophy.

Guanylyl cyclase-A (NPR-A; GC-A) is the major and possibly the only receptor for atrial natriuretic peptide (ANP) or B-type natriuretic peptide. Although mice deficient in GC-A display an elevated blood pressure, the resultant cardiac hypertrophy is much greater than in other mouse models of hypertension. Here we overproduce GC-A in the cardiac myocytes of wild-type or GC-A null animals. Introduction of the GC-A transgene did not alter blood pressure or heart rate as a function of genotype. Cardiac myocyte size was larger (approximately 20%) in GC-A null than in wild-type animals. However, introduction of the GC-A transgene reduced cardiac myocyte size in both wild-type and null mice. Coincident with the reduction in myocyte size, both ANP mRNA and ANP content were significantly reduced by overexpression of GC-A, and this reduction was independent of genotype. This genetic model, therefore, separates a regulation of cardiac myocyte size by blood pressure from local regulation by a GC-mediated pathway.

Animals↗
PubMed2000

Factors affecting the work of an occupational health nurse.

Society, economies, work-life and work are undergoing changes that will have global impact on occupational health services (OHS) and the work of occupational health nurses (OHNs) during the next 5-10 years. These changes will bring new challenges to both occupational health services and representatives of specialist groups within those services. The changes will require new ways of working, work methods, performance monitoring, and evaluation of impacts. These developments will also call for changes in the education of occupational health nurses.

Employment↗
PubMed2000

Metabolic and respiratory effects of theophylline in the preterm infant.

BACKGROUND: Methylxanthines are often administered to preterm infants for the treatment of apnoea. AIMS: To study the effects of theophylline on energy metabolism, physical activity, and lung mechanics in preterm infants. METHODS: Indirect calorimetry was performed for six hours before and after administration of a bolus of theophylline (5 mg/kg) in 18 preterm infants while physical activity was recorded with a video camera. Lung mechanics measurements were performed at baseline and 12 and 24 hours after theophylline treatment. RESULTS: Theophylline increased mean (SEM) energy expenditure by 15 (5) kJ/kg/day and augmented carbohydrate utilisation from 6.8 to 8.0 g/kg/day, but fat oxidation was unchanged. After theophylline treatment, preterm infants had faster respiration, lower transcutaneous CO2, and improved static respiratory compliance without increased physical activity. CONCLUSIONS: A bolus of 5 mg/kg theophylline increased energy expenditure independently of physical activity, increased carbohydrate utilisation, and improved respiratory compliance. The increased energy expenditure could be detrimental to the growth of the preterm infant.

Aminophylline↗
PubMed1998

Ethical issues among Finnish occupational physicians and nurses.

A postal survey was conducted among 200 Finnish occupational physicians and nurses on their ethical values and problems. Both groups considered 'expertise' and 'confidentiality' as the most important core values of occupational health services (OHS) corresponding with newly published national ethical guidelines for occupational physicians and nurses in Finland. Nearly all respondents had encountered ethically problematic situations in their work, but ethical problems with gene testing in the near future were not considered likely to occur. Only 41% of the nurses and 36% of the physicians had received some training in the ethics of OHS, and 76% of all respondents never used available ethical guidelines. According to the results, even if ethics play a vital role in OHS, the ability to critically evaluate one's own performance seems quite limited. This creates a need for further training and more practicable national guidelines.

Adult↗
PubMed1997

Glucose turnover and gluconeogenesis in human pregnancy.

The rate of appearance (Ra) of glucose in plasma and the contribution of gluconeogenesis were quantified in normal pregnant women early ( approximately 10 wk) and late ( approximately 34 wk) in gestation. Their data were compared with those of normal nonpregnant women. Glucose Ra was measured using the [U-13C]glucose tracer dilution method. Gluconeogenesis was quantified by the appearance of 2H on carbon 5 and 6 of glucose after deuterium labeling of body water pool. Weight-specific glucose Ra was unchanged during pregnancy (nonpregnant, 1.89+/-0.24; first trimester, 2.05+/-0.21; and third trimester 2.17+/-0.28 mg/kg.min, mean+/-SD), while total glucose Ra was significantly increased (early, 133.5+/-7.2; late, 162.6+/-16.4 mg/min; P = 0.005). The fractional contribution of gluconeogenesis via pyruvate measured by 2H enrichment on C-6 of glucose (45-61%), and of total gluconeogenesis quantified from 2H enrichment on C-5 of glucose (i.e. , including glycerol [68-85%]) was not significantly different between pregnant and nonpregnant women. Inasmuch as total glucose Ra was significantly increased, total gluconeogenesis was also increased in pregnancy (early pregnancy, 94.7+/-15.9 mg/min; late pregnancy, 122.7+/-9.3 mg/min; P = 0.003). These data demonstrate the ability of the mother to adapt to the increasing fetal demands for glucose with advancing gestation. The mechanism for this unique quantitative adjustment to the fetal demands remains undefined.

3-Hydroxybutyric Acid↗
PubMed1997

Activation of N-methyl-D-aspartate receptors regulates basal electrical activity of oxytocin and vasopressin neurons in lactating rats.

The control of suckling-induced bursting activity of oxytocin neurons and of phasic activity of vasopressin neurons by N-methyl-D-aspartate receptors was investigated in anaesthetized lactating rats. Receptor antagonist or agonist was applied in the vicinity of supraoptic neurons recorded extracellularly. The basal activity of oxytocin neurons was tonically decreased and increased by sustained application of the antagonist and agonist respectively. These effects occurred independently of the effectiveness of suckling to trigger the bursting pattern. When drugs were applied during an ongoing series of milk-ejection-related bursts, these changes were accompanied by parallel modifications in burst amplitude, but burst periodicity was unaffected. In rats failing to milk-eject, antagonist or agonist application did not facilitate the occurrence of bursts. Simultaneous recordings from oxytocin neurons in the contralateral supraoptic nucleus showed that neither their basal nor their bursting activity were affected, indicating the absence of cross-talk between nuclei during such application. The excitatory effect of N-methyl-D-aspartate differed from that induced in the same neurons by i.c.v. injection of oxytocin, which enhanced basal level of activity and burst amplitude, but also increased burst frequency. Furthermore, the distribution of interspike intervals indicated that N-methyl-D-aspartate, but not oxytocin, induced a regularization of the spike pattern. For vasopressin neurons, application of the receptor antagonist inhibited phasic activity by decreasing burst duration and increasing silences. Conversely, N-methyl-D-aspartate enhanced phasic activity, increasing both the duration of the active phases and the frequency of spikes during active phases. When applied to silent vasopressin neurons, N-methyl-D-aspartate induced a regular phasic activity. These results provide evidence that functional N-methyl-D-aspartate receptors regulate the excitability of both oxytocin and vasopressin neurons in lactating rats. These receptors play a paramount role in maintaining a certain level of basal activity which will favour appropriate discharge patterns, tonic for oxytocin neurons and phasic for vasopressin neurons. For oxytocin neurons, this sustained control by ambient glutamate influences the amplitude of bursts, but N-methyl-D-aspartate receptors are probably not involved in the generation of the bursting pattern.

2-Amino-5-phosphonovalerate↗
PubMed1996

Medium-chain triacylglycerols in formulas for preterm infants: effect on plasma lipids, circulating concentrations of medium-chain fatty acids, and essential fatty acids.

Limited information is available on the metabolic fate of medium-chain triacylglycerols (triglycerides) after intestinal absorption and on their influence on essential fatty acid metabolism. We studied in preterm infants the effect of two infant formulas, one with a high (HMCT) and one with a low (LMCT) medium-chain triacylglycerol content, on plasma fatty acids. The HMCT formula contained 46 mol% 8:0 + 10:0 and the LMCT formula (4.8 mol% 8:0 + 10:0) had approximately twice the amount of long-chain saturated and monounsaturated fatty acids as the HMCT. Both formulas had similar contents of linoleic and linolenic acids. Plasma lipids and fatty acids were determined at birth and on day 24 of life in 20 infants fed the LMCT (n = 12) or HMCT (n = 8) formula. Significant amounts of medium-chain fatty acids were found in the systemic circulation of the infants fed the HMCT formula, mainly in plasma fatty acids and triacylglycerols. Despite striking dietary differences, palmitic and stearic acids were not different between groups, indicating de novo synthesis of long-chain fatty acids with the HMCT formula. Plasma phospholipid docosahexaenoic acid was significantly lower in the HMCT group than in the LMCT infants (1.38 +/- 0.07 compared with 1.73 +/- 0.07 mol%, P = 0.002). Our data indicate that a high MCT intake in preterm infants increases lipogenesis, and dietary nonessential fatty acids interfere with the metabolism of docosahexaenoic acid.

Fatty Acids↗
PubMed1993

Glucose metabolism during fasting through human pregnancy: comparison of tracer method with respiratory calorimetry.

Glucose turnover and glucose oxidation were quantified in six normal pregnant women serially throughout pregnancy, using [U-13C]glucose tracer in combination with open-circuit indirect respiratory calorimetry. Five normal nonpregnant women were studied for comparison. With advancing gestation and increase in maternal body weight, there was a proportionate increase in the rate of appearance (Ra) of glucose so that Ra expressed per kilogram body weight did not change from the first to third trimester. The tracer measured rate of glucose oxidation expressed per kilogram body weight also did not change significantly throughout pregnancy. Oxygen consumption (VO2) in pregnant subjects did not differ from that in nonpregnant subjects. However, the respiratory exchange ratio (RER) increased significantly during pregnancy (0.88 +/- 0.53 3rd trimester and 0.76 +/- 0.50 nonpregnant, P < 0.01). The estimated contribution of carbohydrate to VO2 measured by respiratory calorimetry was greater than that measured by the tracer method. This discrepancy became wider as the respiratory quotient increased in late pregnancy. These data suggest that maternal glucose metabolism adjusts throughout pregnancy to meet the increased demands of the conceptus. The discrepancy between tracer method and respiratory calorimetry was probably due to the contribution of (fetal) lipogenesis and (maternal) gluconeogenesis to RER.

Adult↗
PubMed1991

Occupational health services in the Nordic countries.

Occupational health services in the Nordic countries--Denmark, Finland, Iceland, Norway, and Sweden--started as initiatives of single industrial enterprises. Coverage of employees by voluntary occupational health services ranges from an estimated 23% of employees in Denmark to 93% of employees in Finland. Contents of OHS in the Nordic countries correspond mainly with the ILO Convention (161/85) on OHS. The services are primarily directed to preventing work related problems and achieving a better working environment. Employers are responsible for the total costs of occupational health services in all Nordic countries, but each nation has state reimbursement plans to help cover the costs. However, additional advantages in the subsidy system are needed to stimulate even the smaller enterprises to join the occupational health system.

Humans↗
PubMed1990

Rheumatology algorithms for primary care physicians.

Primary care physicians were trained on three rheumatology topics to assess the effectiveness of an educational strategy for continuing medical education. Algorithm training was shown to be at least as effective as that based on standard prose monographs. Both training groups improved their knowledge of patient management skills but there were no statistically significant differences between groups in the amount learned. When algorithms were used to design text materials, the designed texts required less study time than did the annotated clinical algorithms alone. That difference was significant for the shoulder pain materials (P less than 0.05) but not for the osteoporosis materials. The ratio of knowledge gained to study time was significantly higher for the algorithm group on the low back pain topic (P less than 0.05) but not for the other topics. Taped interview problems tests were studied as a method for assessing patient management skills related to problem-specific indicator conditions and were found to produce interrater reliability greater than 0.80 on five of the six tests.

Clinical Protocols↗
PubMed1988

Differential inhibition of mitogen induced T cell proliferation by 5-azacytidine and cytosine-arabinoside.

The cytotoxic drugs 5-azacytidine and cytosine-arabinoside influence the enzymatic methylation of DNA in opposite ways (1,2). The in vitro effects of these two drugs on Con A induced proliferation of thymic and splenic rat lymphocytes were investigated. Cytosine-arabinoside was found to inhibit mitogen induced proliferation already at a concentration of 0.001 microM, whereas 5-azacytidine was inhibitory only above concentrations of 1 microM. A stimulation of mitogen induced T cell proliferation was consistently seen with 5-azacytidine, but not with cytosine-arabinoside, at concentrations lower than the cytotoxic concentration. The results show that 5-azacytidine and cytosine-arabinoside interfere with mitogen stimulated lymphocyte proliferation by different mechanisms and suggest that hypomethylated DNA plays a role in the proliferation of T cells.

Animals↗
PubMed1987

T cell hyperreactivity in obese strain (OS) chickens. Different mechanisms operative in spleen and peripheral blood lymphocyte activation.

The enhanced T cell reactivity (ConA hyperresponsiveness and IL 2 hypersecretion) of spleen lymphocytes of Obese strain (OS) chickens with spontaneous autoimmune thyroiditis has recently been shown to be due to a defect in macrophage-derived non-specific suppressor factors that regulate IL 2 secretion and IL 2-promoted T lymphoblast proliferation in normal healthy animals. In the present study, we present several lines of evidence that the increased T cell response of peripheral blood lymphocytes (PBL) of OS chickens is due to mechanisms entirely different from the described dysregulation of splenic T cells: 1) In contrast to the splenic macrophages, peripheral blood monocytes of OS animals are not deficient in the production of IL 2 antagonistic activity (IAA); 2) therefore, cocultivation of PBL from OS and Normal White Leghorn (NWL) chickens in communicating culture chambers did not abrogate the difference in Con A response as previously observed with spleen lymphocytes. 3) Immunofluorescence with a monoclonal antibody (INN CH 16) against the chicken IL 2 receptor revealed enhanced numbers of mitogen activatable T cells in OS PBL but not OS spleen lymphocytes. 4) After prolonged Con A stimulation of PBL, OS and NWL lymphoblasts did not differ from each other in functional aspects. In contrast to this, Con A lymphoblasts from OS spleens exhibited enhanced staining with INN CH 16 in parallel with an increased proliferative response to IL 2. Thus, the primary T cell dysfunction involved in the development of autoimmune disease in OS chickens is the result of at least two separate regulatory defects.

Animals↗
PubMed1979

First-aid preparedness in small workplaces with special reference to occupational health services.

First-aid preparedness was surveyed in 163 small firms employing 2,400 persons. Although 11% of the employees had received first-aid training, half of the firms lacked first-aiders. Only one-fourth of the first-aid kits were equipped according to instructions. Checking and maintenance of the equipment, as well as information about first aid at the place of work, were generally inadequate. Instructions were commonly lacking for the safe use of chemical substances. Only 9% of the firms fully complied with the requirements for optimum first-aid preparedness. Employers at small firms seem not to be sufficiently aware of their liabilities with regard to first aid. Yet, most of the faults and defects could be corrected by means of arrangements within the firms once the instructions were better known. During their visits to places of work occupational health personnel should inspect the first-aid preparedness and advise the employer on first-aid requirements. In addition the expertise of the insurance company, the local Red Cross or the regional institute of occupational health may be utilized.

Finland↗