PubMed Health⌕ Search

Biomedical subjects

M Nyman

Publications and source records attributed to M Nyman.

At least 37 records · Page 2Linked to original sources
PubMed1998

Optimization of selectivity in high-performance liquid chromatography using desirability functions and mixture designs according to PRISMA.

A computer program for the mobile phase optimization of high-performance liquid chromatography (HPLC) is described. The desirability function technique combined to the prisma mixture design was employed to enhance the quality of HPLC separations. The use of statistical models to predict the behaviour of retention times (tR) and band broadening at the different eluent compositions obtained by prisma was examined for dansyl amides and coumarins. The study showed that the dependence between the eluent composition and tR values of dansyl amides and coumarins can be expressed using quadratic regression models with a high degree of accuracy. Band broadening given by means of the band width at half-height (wh) was described by a linear regression model. Both models were used in calculating and predicting the resolution (Rs) in various solvent combinations. The desirability function converted the calculated (Rs) value into the desirability value (D), and the overall optimum was then defined by means of the overall desirability. The optimal eluent mixtures for the separation of compounds were easily read from the contour plot inside the horizontal plane of the prisma model. A good separation was achieved using the optimized solvent combination. Depending on the aims of the optimal separation, the program allows either optimization of critical pairs or achieving the overall optimum giving a reasonable separation for as many compounds as possible.

Chromatography, High Pressure Liquid↗
PubMed1998

Mechanical Properties of Large Arteries in Mother and Fetus during Normal and Diabetic Pregnancy.

> Objective: To assess the influence of diabetes mellitus on the mechanical wall properties of large maternal and fetal arteries in pregnant women. Methods: Prospective serial monitoring of arterial wall characteristics, using ultrasonic phase-locked tracking of vessel diameters and oscillometric brachial blood pressure measurements. Ten pregnant women with insulin-dependent diabetes mellitus and 15 with gestational diabetes were studied and compared with 20 women in uncomplicated gestation. Results: In women with uncomplicated pregnancy, the stiffness index and the elastic modulus of the maternal aorta were lower (both P < 0.05), whereas the pulse amplitude and the strain were higher (both P < 0.05) in the 12th gestational week than in the 6th week postpartum. These differences did not appear in pregnancy complicated by insulin-dependent diabetes. In early gestation, higher aortic stiffness index and elastic modulus (both P < 0.05) and lower pulse amplitude and strain (both P < 0.05) were recorded in gravidae with insulin-dependent diabetes compared with nondiabetic pregnant women; those with gestational diabetes were not detected in early pregnancy. No intergroup or intragroup differences of stiffness index and pulse amplitude were found in the carotid artery in corresponding gestational ages. In the fetal aorta, the pulse wave velocity increased during the third trimester of normal gestation (P < 0.05) but not in insulin-dependent diabetic pregnancy. Conclusion: The difference found concerning the aortic stiffness between women with insulin-dependent diabetes during pregnancy and those with uncomplicated pregnancy might be interpreted as an altered cardiovascular adaptation to pregnancy in women with diabetes.

Journal Article↗
PubMed1997

Antibody response to Arcanobacterium haemolyticum infection in humans.

Arcanobacterium haemolyticum causes pharyngitis, exanthema, and other infections. The evidence of the pathogenicity of A. haemolyticum depends on clinical descriptions of culture-positive patients and a comparison of carrier rates of patients with pharyngitis and healthy, matched controls. In this investigation, the antibody response of the host was studied for the first time, using SDS-PAGE and Western blot analyses. Paired acute and convalescent sera showed development of antibodies to A. haemolyticum in 7 of 8 patients. The antibodies reacted primarily with four distinct cell wall-associated proteins with estimated molecular masses of 80, 60, 50, and 30 kDa. Moreover, the reactivity of convalescent sera from 19 patients was compared with that of sera from 19 controls. Antibodies to A. haemolyticum were found in sera from 16 patients and 6 controls (P < .005); the antibody response of the patients was strong compared with that of the controls. These results indicate that A. haemolyticum infection induces an antibody response in the host.

Acute Disease↗
PubMed1996

Audible in utero sound caused by the ultrasonic radiation force from a real-time scanner.

While investigating in utero sound levels during vibro-acoustic stimulation on the maternal abdomen it was noticed that noise level increased when the real-time ultrasonic scanner beam was directed at the sensing hydrophone. The noise was recorded and later analysed for frequency content and waveform. It appeared related to the scanning and frame rate frequencies of the scanner used. Sounds may originate from radiation pressure produced when the ultrasound beam is absorbed by tissue or reflected from bone or the metal hydrophone. This implies that although ultrasound cannot be heard per se, any modulation of its intensity will produce vibrations in the maternal tissues or reflecting structures such as skull bone, and especially stapes, malleus and incus, that would be heard as sound by the fetus. The intensity of the sound produced varied with orientation of the transducer beam and this may itself produce a stimulation. Based on our recordings (Fig. 1), it was calculated (please see Appendix) that the fetus would hear a sound corresponding to 84dB noise pressure level in air.

Acoustic Stimulation↗
PubMed1996

A prospective study of antibodies against parvovirus B19 in pregnancy.

BACKGROUND: Parvovirus infection during pregnancy has been reported to be associated with spontaneous abortion and fetal loss. OBJECTIVE: To show the incidence of antibodies against Parvovirus B19 early in pregnancy and sero-reactivities during and after pregnancy. STUDY DESIGN: In a prospective study during a non-epidemic period, 457 women admitted to an antenatal care center were included. Serum samples were collected at 7-13, 21, and 33 weeks of gestation, and 7-9 weeks after delivery. METHOD: Samples were evaluated for parvovirus specific IgG and IgM against two different parvovirus antigens. RESULTS AND CONCLUSION: Parvovirus specific antibodies were present in 81% of the women in the first sample. Six women (six of 88 susceptible, 6.8%) seroconverted and 28 women (28/369, 7.6%) boosted their antibody response during or after pregnancy. All gave birth to healthy infants. One woman free of symptoms experienced an intrauterine fetal death at 37 weeks of gestation. She had no rise in B19 antibodies during pregnancy, but parvovirus DNA was found in maternal serum samples and in the placenta.

Abortion, Spontaneous↗
PubMed1995

Determination of digestible energy values and fermentabilities of dietary fibre supplements: a European interlaboratory study in vivo.

The performance of methods to determine energy conversion factors for dietary fibre (DF) supplements and fermentability (D) values of their non-starch polysaccharides (NSP) was investigated. Heats of combustion, digestible energy (DE) and D values were determined on five DF supplements in five European laboratories on five separate occasions. In each instance the DF supplements were fed to juvenile male Wistar rats at two doses, 50 and 100 g/kg basal diet, for 3 weeks with food and faeces collected in the 3rd week. Among-laboratory variations in heats of combustion (delta Hc) were < 2%. DE values (kJ/g dry weight) at the upper and lower doses respectively were: 10.4 and 9.9 for a high-methoxyl apple pectin, 9.5 and 9.4 for a sugar-beet DF supplement, 12.2 and 12.7 for soyabean DF supplement, 3.8 and 4.0 for maize bran, and 0.3 and 0.3 for Solka-floc cellulose. Variations among laboratories, among occasions and among animals were < 1, < 2 and < 2.5 kJ/g respectively. The among-occasion: among-laboratory variance ratio for DE was 0.5, suggesting the method performed equally well in all laboratories. There was no evidence of learning of fatigue or fatigue in the performance of the method. D values were also independent of dose and at the high and lower doses were: pectin 0.92 and 0.95, sugar-beet NSP 0.68 and 0.68, soyabean NSP 0.86 and 0.88, maize bran 0.17 and 0.18, cellulose 0.07 and 0.06. Among-laboratory variance tended to increase with decreasing fermentability and ranged from 0.03 to 0.18. The DE and D data were not significantly different from a previously proposed relationship DE = 0.7 x delta Hc x D, where delta Hc is the heat of combustion of the supplement. We conclude that while the among-laboratory variation in the D of difficult-to-ferment NSP is too large for the reliable prediction of energy value the method for the direction determination of DE is both reproducible and repeatable, that DE is independent of dosage of DF supplement up to 100 g/kg diet, and that it is safe to discriminate between energy values with a precision of 3 kJ/g. The conversion of both DE and D to net metabolizable energy for the purpose of food labelling, tables and databases is described.

Animals↗
PubMed1995

Ulcerative colitis and indeterminate colitis in the city of Malmö, Sweden. A 25-year incidence study.

BACKGROUND: This study was designed to assess time trends in the incidence of ulcerative colitis and indeterminate colitis in an urban population. METHODS: Medical records of in- and out-patients with inflammatory bowel disease were reviewed by a panel to establish the diagnosis. All histopathologic specimens and almost all radiographs were re-examined. RESULTS: During the time period 1958 to 1982 there were 354 new cases of definite ulcerative colitis, 117 of probable ulcerative colitis, and 100 of indeterminate colitis. This corresponds to an average annual incidence per 100,000 of 5.5, 1.8, and 1.6, respectively. The incidence was higher in men than in women. Peak incidence was between 20 and 29 years, but indeterminate colitis was most common in 10- to 19-year-old males. The incidence was stable from 1958 to 1972 but then increased in almost all age groups in both sexes. The increase in annual incidence of definite ulcerative colitis from 4.2 to 9.4/10(5) corresponds to an average annual increase of about 5% (p < 0.001). The increase in the incidence of definite ulcerative colitis was due to an increased proportion of patients with proctitis. CONCLUSIONS: This study has shown an increased incidence of ulcerative colitis and indeterminate colitis, and we have found no reason to believe that this is a spurious finding.

Adolescent↗
PubMed1995

Influence of processing and cooking of carrots in mixed meals on satiety, glucose and hormonal response.

The influence of processing and cooking on the metabolic response to carrots in mixed meals was explored in two consecutive harvest years. The contribution of dietary fibre (4.4 g 1989 and 6.6 g 1990) from carrots was chosen to be different in order to compare effects with varying doses. The meals, composed of carrots, creamed potatoes, meat balls, lingonberry jam, white bread and light beer, were served in the morning after an overnight fast to 10 healthy male volunteers. Carrots were investigated raw, processed (blanched and frozen) and variously cooked (thawed, boiled and microwaved). The amount of dietary fibre from the vegetable, and the content of energy, digestible carbohydrates, fat and protein were similar in the meals compared. Significantly lower glucose, insulin and C-peptide responses and higher satiety scores were elicited with raw carrots than with microwaved ones, harvest year 1989. The next year, with a higher dietary fibre intake from carrots, there were significant effects of processing only on the glucose response. Plasma beta-carotene levels tended to be higher postprandially with raw carrots than with microwaved ones. Hence, ordinary processing and cooking of vegetables can affect the metabolic response to a mixed meal. However, the influence seems to be varying and of minor importance in ordinary meals. Increasing vegetable portions entailing a higher soluble fibre content and a higher viscosity could further reduce the influence of processing.

Adult↗
PubMed1995

Satiety effects of spinach in mixed meals: comparison with other vegetables.

The effects of vegetables in mixed meals on satiety were evaluated by varying the dose (portions 150 and 250 g containing 4.3 and 7.2 g of dietary fibre, respectively) and structure (cut and minced) of microwaved spinach. A control meal without spinach and the test meals with spinach were balanced regarding energy (2000 kJ) and digestible carbohydrates (59 g, 51 E%) and with protein and fat as far as possible similar. The meals were served in the morning, after an overnight fast, to ten healthy male volunteers. Satiety was registered and blood glucose as well as plasma insulin and C-peptide were analysed at regular intervals until 3.5 h postprandially. The largest spinach portions augmented satiety and reduced the postprandial glucose response. The total satiety scores seemed to be correlated positively to both the dietary fibre and the water content in the vegetable. Differences in structure had no influence on satiety scores.

Adult↗
PubMed1994

Dose-response effects of boiled carrots and effects of carrots in lactic acid in mixed meals on glycaemic response and satiety.

OBJECTIVE: To evaluate the effect of dosage on the metabolic response to vegetables added to a mixed lunch meal, and to relate the amounts to the tripartite plate model. Carrots were chosen as an example, and the carrots were blanched, frozen and boiled to include possible effects of processing and cooking. The effects of carrots steeped in lactic acid, as produced at fermentation, were also studied. DESIGN: The test meals with carrots, and the control meal without vegetables, were balanced regarding energy (2000 kJ) and digestible carbohydrates (60 g) and similar in fat (17 g) and protein (16-19 g) content. The carrot portions of 100, 200 and 300 g contained 2.9, 5.8 and 8.7 g dietary fibre respectively. The meals were served in the morning after an overnight fast and in random order. Blood samples for the analysis of blood glucose, plasma insulin and C-peptide were collected and satiety was graded until 210 min postprandially. SETTING: The study was performed at the research laboratory, Dalby Health Sciences Centre (primary care). SUBJECTS: The 10 healthy, male volunteers, around 40 years of age, were recruited at random from the district's population list. None dropped out. RESULTS: The larger the carrot portion the lower were the glucose and insulin/C-peptide responses and the higher the satiety scores. The minimum amount causing significant effects was 200 g. According to the plate model, 200 g of boiled carrots was the most that could be included on half the plate. Addition of lactic acid to 200 g carrots augmented the effects on satiety scores and hormonal response. CONCLUSIONS: The addition of generous amounts of vegetables to a mixed meal improves the metabolic response.

Adult↗
PubMed1994

The relations of emotionality and regulation to children's anger-related reactions.

The purpose of this study was to examine the relations of emotionality (intensity and negative emotion) and regulation (attentional control, mode of coping) to preschoolers' naturally occurring anger reactions. School personnel's ratings of 4-6-year-olds' constructive coping and attentional control were associated with boys' constructive anger reactions whereas their ratings of acting out versus avoidant coping, emotional intensity, and anger intensity generally were correlated with low levels of constructive reactions to anger. Mothers' reports of children's constructive coping and low emotional intensity were associated with children's use of nonabusive language to deal with anger, whereas aggressive coping and negative emotionality were associated with escape behavior when angered. The findings are consistent with the conclusion that individual differences in emotionality and regulatory skills are associated with children's constructive versus nonconstructive anger reactions.

Adaptation, Psychological↗
PubMed1993

Effects of different vegetables in mixed meals on glucose homeostasis and satiety.

Different vegetables--carrots, peas, Brussels sprouts and spinach--were added to a typical Swedish lunch test meal in portions of 96-164 g. The test and the control meals without vegetables were balanced with respect to digestible carbohydrates (59.7 g) and energy (2000 kJ, 475 kcal), and as far as possible also concerning protein and fat. The added vegetables contained 4.4 g dietary fibre. The meals were prepared by microwave heating and served in the morning after an overnight fast to 10 healthy, male volunteers. Postprandial blood glucose, plasma insulin and C-peptide levels were measured at regular intervals until 210 min. The satiety was graded on a simple scale of 1-10. The meal with spinach elicited significantly lower insulin and C-peptide responses than the control meal, but no significant differences in glucose response or satiety were observed. The other vegetables tested showed no significant effects either on glucose and hormonal responses or on satiety.

Adult↗
PubMed1992

Effect of dietary fiber on the disposition and excretion of a food carcinogen (2-14C-labeled MeIQx) in rats.

We studied to what extent dietary fiber may affect uptake, retention, and excretion of a food carcinogen (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, MeIQx) occurring in fried meat. Four diets--one fiber-free control and three containing either insoluble dietary fiber isolated from sorghum (100 g/kg) and wheat bran (100 g/kg) or the highly soluble pectin (50 g/kg)--were investigated. The fiber diets were given in amounts of 10 g/day to rats. Thus, each rat received 1 or 0.5 g fiber and 100 micrograms 2-14C-labeled MeIQx uniformly mixed in its daily diet. A 4-day adaptation period with unlabeled MeIQx was followed by a 5-day experimental period with 14C-labeled MeIQx, during which urine and feces were collected separately for analysis of radioactivity and mutagenicity. Furthermore the composition and the fermentability of the dietary fiber were determined. The present study shows that a diet containing fiber, especially fiber isolated from sorghum and wheat bran, affects the excretion pattern of the food carcinogen MeIQx in a manner suggesting a lower uptake and a decreased transit time through the gastrointestinal tract in a more diluted form than a nonfiber diet. Furthermore, less radioactivity was retained in the kidneys with sorghum and wheat bran than with the other two diets. On the other hand, none of these types of dietary fiber affected the retention of the hepatocarcinogen MeIQx in the liver 24 hours after the last oral intake. DNA adducts were formed to a higher extent in the kidney than in the liver. The highest levels were found in animals given the wheat bran diet.

Animals↗
PubMed1992

A four-year follow-up of hearing and development in children exposed in utero to vibro-acoustic stimulation.

OBJECTIVE: To obtain information of hearing and neuro-development in children exposed to vibro-acoustic stimulation in utero. DESIGN: Information collected from Swedish child care programmes. SETTING: Department of Obstetrics and Gynaecology, Karolinska Institutet, Danderyd University Hospital, Sweden. SUBJECTS: Children of 460 mothers exposed to vibro-acoustic stimulation for the assessment of fetal well-being during high- and low-risk pregnancies during 1985-1987. MAIN OUTCOME MEASURES: Auditory test (20-25 dB at eight frequencies between 500 and 8000 Hz) and general neurological examination at four years of age. RESULTS: No hearing damage or neuro-developmental abnormalities that could be connected to the vibro-acoustic stimulation were found. CONCLUSIONS: Vibro-acoustic stimulation, as applied in clinical practice, did not endanger either neurological development or hearing in children exposed in utero.

Acoustic Stimulation↗
PubMed1992

Vibro-acoustic stimulation in high-risk pregnancies; maternal perception of fetal movements, fetal heart rate and fetal outcome.

Maternal perception of fetal movement in response to vibro-acoustic stimulation was compared with antenatal fetal heart rate monitoring as a test of fetal well-being in a population of gravidae with high-risk pregnancies (n = 517), admitted to the high-risk ward at Danderyd Hospital, Karolinska Institutet; a total of 2,015 tests were performed. The sensitivity and the specificity of the test compared to the fetal heart rate tracing was 81% and 89% respectively. If the test was performed within 24 hours of delivery, its predictive value for fetal asphyxia (i.e. a 5-minute Apgar score < 7) was 14% (7/49). Ten per cent of the patients felt no fetal movement in response to stimulation (irrespective of gestational age). In five cases where fetal heart rate tracings were pathological, stimulation nonetheless produced fetal movement and fetal outcome was good. Pathological heart rate tracings and no fetal movement in response to stimulation were present in 30 cases (out of 251 with no fetal movements at stimulation), in seven of which the infants had 5-minute Apgar scores < 7. Although many patients underwent repeated vibro-acoustic stimulation, there was no evidence of fetal habituation to the test. On 24 occasions (i.e. 1.2%), the patient denied vibro-acoustic stimulation, mostly because of previous discomfort due to vigorous fetal response. Where resources are limited, maternal perception of fetal movements in response to vibro-acoustic stimulation might be a useful alternative for preliminary screening of high-risk pregnancies.

Acoustic Stimulation↗