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Biomedical subjects

M Persson

Publications and source records attributed to M Persson.

At least 73 records · Page 4Linked to original sources
PubMed1998

[International comparisons of health care resources. Expenditure shared the GNP is inadequate. Complementary real measures are necessary].

Since the health care expenditure share of the GNP (gross national product) is a measure difficult to interpret, its use can yield erroneous results in comparing health care sector development in different countries. A complementary measure of health care resources is the size and structure of the health care labour force. Information from Sweden, Denmark, the United Kingdom and the USA shows that development in expenditure share of the GNP in no way reflects development in labour resources in the respective countries. Ranking of national costs differs depending on the measures used, which is partly to be explained by differences in relative prices in terms of various investment factors--e.g., salaries of qualified personnel. The generally slow wages trend in the Swedish health care sector is a contributory factor explaining why the marked increase in the labour force during the 1970s and 1980s is incompletely reflected in the health care expenditure share of the GNP. Studies of personnel resources at the hospital level in the above-mentioned countries have shown marked national differences to exist in terms of working hours, service contracts and job descriptions, which further explains the differences manifest at an aggregate level.

Costs and Cost Analysis↗
PubMed1998

Synergistic interactions of bradykinin, thrombin, interleukin 1 and tumor necrosis factor on prostanoid biosynthesis in human periodontal-ligament cells.

Prostaglandins are involved in force-induced orthodontic tooth movement. Bradykinin (BK) and thrombin are known to cause a significant time- and concentration-dependent burst of prostanoid biosynthesis in cultured human periodontal-ligament (PDL) cells. The aim now was to investigate interactive effects between interleukin 1 alpha, -beta (IL-1 alpha, -1 beta), tumour necrosis factor-alpha,-beta (TNF-alpha, -beta) and BK or thrombin on prostaglandin biosynthesis in human PDL cells. IL-1 alpha and -1 beta produced time- and concentration-dependent stimulation of prostanoid biosynthesis [prostaglandin (PG)E2 and 6-keto-PGF1alpha]. Synergistic stimulation of prostanoid biosynthesis was demonstrated when BK or thrombin were added together with IL-1 alpha or -1 beta. BK and IL-1 beta both significantly stimulated the release of [3H]arachidonic acid. No synergistic effect on [3H]arachidonic acid release was seen when BK and IL-1 beta were added simultaneously. These data suggest that the synergistic effect of BK and IL-1 beta on prostanoid biosynthesis is not due to interactions at the receptor level nor to enhanced release of arachidonic acid, but may be due to increased activity of cyclo-oxygenase. Also, TNF-alpha and -beta produced a concentration-dependent stimulation of PGE2 formation in cultured human PDL cells. Synergistic effects of BK and thrombin were demonstrated when PGE2 production was stimulated in combination with TNF-beta. In addition, a synergistic effect on the PGE2 response to IL-1 alpha or -1 beta was demonstrated when added in combination with TNF-alpha. These experiments demonstrate synergistic interactions between BK, thrombin, IL-1 and TNF on prostaglandin biosynthesis in cultured human PDL cells. The findings suggest that inflammatory mediators may act in concert in stimulating prostanoid production in response to pro-inflammatory stimuli. As an inflammatory reaction is seen in the periodontal ligament when teeth are orthodontically treated, this synergistic interaction may be of importance in force-induced tooth movement.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Mandibular morphology and the efficacy of a mandibular advancement device in patients with sleep apnoea.

The aim of the present study was to evaluate whether the outcome of treatment using an intraoral mandibular advancement device in patients with obstructive sleep apnoea is associated with the mandibular morphology. The effects of the device on apnoeas and sleep were evaluated in 32 men with obstructive sleep apnoea in continuous polysomnographic sleep recordings including body position, during one night without the device and one night with it. Mandibular morphology variables were measured on cephalograms. The odds ratio for a supine apnoea-hypopnoea index of below 15 during treatment was 17 for a mandibular plane angle of 38 degrees or below, and 26 for a lower anterior face height of less then 73 mm. The outcome of treatment in the lateral sleep position was unrelated to any mandibular morphology variable. Patients with supine-dependent sleep apnoea defined by a supine apnoea-hypopnoea index of 10 or above and a lateral apnoea-hypopnoea index of below 10 had an odds ratio of 7 to have an orthognathic mandible with an SNB angle of 78 degrees or above. The present study suggests that a successful apnoea reduction using a mandibular advancement device is associated with a normal mandibular plane angle and a small lower anterior face height.

Adult↗
PubMed1998

Treatment success with a mandibular advancement device is related to supine-dependent sleep apnea.

STUDY OBJECTIVE: To evaluate the effect of a mandibular advancement device in patients with supine-dependent sleep apnea and patients with non-supine-dependent sleep apnea. DESIGN: Prospective study. SETTING: Department of Respiratory Medicine, University Hospital, Umeå, Sweden. PATIENTS: Twenty-six patients with obstructive sleep apnea. INTERVENTION: Individually fabricated and adjusted mandibular advancement devices. MEASUREMENTS: Overnight polysomnographic sleep recordings with and without the device. Supine-dependent sleep apnea was defined when the supine apnea-hypopnea index was > or = 10, together with a lateral apnea-hypopnea index of < 10. Non-supine-dependent sleep apnea was considered when the lateral apnea-hypopnea index was > or = 10. RESULTS: In 12 patients with supine-dependent sleep apnea, the device reduced the supine apnea-hypopnea index from a median of 41 (range, 16 to 70) to 5.9 (range, 0.0 to 15) (p < 0.01). In 14 patients with non-supine-dependent sleep apnea, the treatment reduced the supine apnea-hypopnea index from 44 (range, 1.8 to 73) to 21 (range, 6.3 to 60) (p < 0.05) and the lateral apnea-hypopnea index from 21 (range, 12 to 70) to 4.5 (range, 0.0 to 31) (p < 0.01). The odds ratio for a successful apnea reduction to an apnea-hypopnea index of < 10 in both the supine and the lateral positions was 30 for supine-dependent sleep apnea adjusted for age, obesity, mandibular advancement, and mandibular opening (p < 0.01). CONCLUSION: Successful apnea reduction with a mandibular advancement device is highly related to supine-dependent sleep apnea.

Adult↗
PubMed1998

Differential regulation of amino acid exchange and protein dynamics across splanchnic and skeletal muscle beds by insulin in healthy human subjects.

To define the mechanism of insulin's anticatabolic action, the effects of three different dosages of insulin (0.25, 0.5, and 1.0 mU x kg(-1) x min(-1)) versus saline on protein dynamics across splanchnic and skeletal muscle (leg) beds were determined using stable isotopes of phenylalanine, tyrosine, and leucine in 24 healthy subjects. After an overnight fast, protein breakdown in muscle exceeded protein synthesis, causing a net release of amino acids from muscle bed, while in the splanchnic bed protein synthesis exceeded protein breakdown, resulting in a net uptake of these amino acids. Insulin decreased (P < 0.003) muscle protein breakdown in a dose-dependent manner with no effect on muscle protein synthesis, thus decreasing the net amino acid release from the muscle bed. In contrast, insulin decreased protein synthesis (P < 0.03) in the splanchnic region with no effect on protein breakdown, thereby decreasing the net uptake of the amino acids. In addition, insulin also decreased (P < 0.001) leucine nitrogen flux substantially more than leucine carbon flux, indicating increased leucine transamination (an important biochemical process for nitrogen transfer between amino acids and across the organs), in a dose-dependent manner, with the magnitude of effect being greater on skeletal muscle than on the splanchnic bed. In conclusion, muscle is in a catabolic state in human subjects after an overnight fast and provides amino acids for synthesis of essential proteins in the splanchnic bed. Insulin achieves amino acid balance across splanchnic and skeletal muscle beds through its differential effects on protein dynamics in these tissue beds.

Adult↗
PubMed1998

An experimental study of a concurrent primary infection with bovine respiratory syncytial virus (BRSV) and bovine viral diarrhoea virus (BVDV) in calves.

Experimental infections with bovine respiratory syncytial virus (BRSV) and bovine viral diarrhoea virus (BVDV) were performed to study the effect of concurrent BRSV and BVDV infections. Twelve seronegative calves, in 3 groups, were inoculated on a single occasion with pure BRSV (group A), BRSV and noncytopathogenic BVDV (group B) or mock infected (group C). Mild respiratory symptoms were recorded 4 to 5 days post inoculation (dpi) in group A and group B calves. One calf in group A was severely affected and required medical treatment. In group B, fever (40.7-41.4 degrees C) was prominent 7 to 8 dpi. Only calves in group B were BVDV positive in purified lymphocytes at 2 to 14 dpi and showed increased serum interferon levels, with a peak at 4 dpi, indicating BVDV to be responsible for inducing the rise. BRSV was detected in lung lavage fluids up to 7 dpi for group A calves, compared to 11 dpi for group B and calves in this group also seroconverted later displaying lower BRSV titers. The time lag before an antibody response and the titers recorded in group B, indicated that the duration of BVDV infection in lymphocytes negatively influenced the capacity to mount a BRSV antibody response.

Animals↗
PubMed1997

GroEL provides a folding pathway with lower apparent activation energy compared to spontaneous refolding of human carbonic anhydrase II.

The kinetics of the refolding of the enzyme, human carbonic anhydrase II (HCA II), at different temperatures, together with the Escherichia coli chaperonin GroEL, has been studied. The Arrhenius plots for the spontaneous, GroEL-assisted, and GroEL/ES-assisted refolding of HCA II show that the apparent activation energy (E(a)) is lower in the presence of the chaperonin GroEL alone than for the spontaneous reaction, whereas the apparent activation energy for the GroEL/ES-assisted reaction is almost the same as for the spontaneous reaction (85, 46, and 72 kJ/mol, for the spontaneous, GroEL, and GroEL/ES-assisted reactions, respectively).

Carbonic Anhydrases↗
PubMed1997

Malnutrition in geriatric patients: a neglected problem?

The nutrient intake in geriatric long-stay patients and the mortality risk associated with low energy intake were studied in 61 patients, 43 women and 18 men, with a mean age of 87 years, at a geriatric long-stay care hospital during a 6-month follow-up. Dietary intake was assessed with a 9-day dietary record. Energy expenditure was calculated assuming a physical activity level of 1.33 x basal metabolic rate (BMR), predicted from equations given by FAO/WHO. Mean energy intakes were 1557 kcal in men and 1280 kcal in women; 84% of the patients had an intake below estimated energy expenditure and 30% were below estimated BMR. Only 5% received dietary supplement. Eleven out of the 61 patients died during the follow-up and the deceased had lower energy intake than the others (1185 kcal vs 1401 kcal, P < 0.05). An energy intake below median (1378 kcal) was associated with an age adjusted increased 6-month mortality risk, odds ratio 12.5. A high proportion of geriatric long-stay patients report dietary intake far below present recommendations and are thereby at risk for having/developing malnutrition. Improved surveillance of geriatric long-stay patients' dietary habits seems justified.

Activities of Daily Living↗
PubMed1997

White spot reduction when using glass ionomer cement for bonding in orthodontics: a longitudinal and comparative study.

The aim of this clinical study was to test the benefit from using glass ionomer cement (GIC) instead of a conventional diacrylate in bracket bonding for the prevention of white spot formation. Before treatment 7.2 per cent of all examined surfaces (n = 222) were classified as having white spots. No additional fluoride treatment other than fluoride toothpaste was prescribed. At debonding 8-39 months later, white spots were found in 24 per cent of the surfaces bonded with the cement, significantly lower than the 40.5 per cent bonded with the diacrylate (P < 0.01). At recall 12 months after debonding (examined surfaces n = 214) the frequency of surfaces with white spots was reduced to 22 and 24 per cent respectively. Re-examination after a further 12 months (n = 160) showed that white spot surfaces were less frequent with the cement (16 per cent compared with the diacrylate 29 per cent), but still significantly more frequent in both groups than before treatment. With longer treatment time (17 months) teeth bonded with diacrylate were more frequently affected with white spots (P < 0.05). Neither sex nor age affected the results. It is concluded that the use of a GIC for orthodontic bonding will result in a significant reduction in the number of white spot surfaces at debonding compared with the use of conventional diacrylate. Although markedly reduced in both groups, the number of affected surfaces was still higher 2 years after debonding than before treatment.

Acrylates↗
PubMed1997

Bond strength and clinical efficiency for two light guide sizes in orthodontic bracket bonding.

The purpose of this study was to establish a possible increase in efficiency in bracket bonding with light-cured adhesive by using a larger size on the light transmitting unit. Two light guides were compared, a standard-sized 11-mm light guide and a 19-mm elliptical extra broad light guide, the latter designed to allow simultaneously curing of two adjacent brackets. Fifty extracted human premolars mounted in five phantom maxillary arches were bonded according to a standard procedure with Mini Uni-Twin stainless steel brackets. The two light guides were randomly chosen for each half of the maxillary arch. After bonding, all teeth were tested for tensile bond strength to failure. In the clinical study 30 patients were bonded according to a split mouth technique with the two light guides alternatively used randomly for each side of the jaw. Time for bonding and the occurrence of bracket failures were recorded. The results showed no statistically significant differences between the standard and elliptical light guides regarding tensile bond strength, or bracket failure frequency. However, with the larger light guide size a significantly shorter total bonding time for each patient was required. It is therefore concluded that the elliptical light guide in combination with a light transmitting unit of sufficient quality gave a similar bonding result as the standard light guide, offering the clinician a reduction in chair side time during the bonding procedure.

Acrylic Resins↗
PubMed1997

Identification of Serpulina species associated with porcine colitis by biochemical analysis and PCR.

A PCR system for the detection and identification of group IV spirochetes (Serpulina pilosicoli) was designed to complement biochemical tests, e.g., the hippurate hydrolysis and beta-glucosidase tests, and to verify the accuracy of a previously proposed biochemical classification system. The PCR assay was based on amplification of a segment of the 16S rRNA gene. Both primers were constructed to selectively amplify the 16S rRNA gene of Serpulina pilosicoli. All analyzed Serpulina strains exhibiting the capacity to hydrolyze hippurate and lacking beta-glucosidase activity, including the type strain for spirochetal diarrhea, P43, were amplified with the PCR system. All other tested strains, including type and field strains of different phenotypes of Serpulina species, as well as Salmonella species, Campylobacter species, and Escherichia coli strains, were negative in the assay. Among the tested strains were 18 Scottish field isolates originating from the mucosae of pigs with colitis. A simple classification scheme, suitable for routine classification of porcine intestinal spirochetes, is also presented. The scheme is based on hemolysis, indole production, and the hippurate hydrolysis test.

Animals↗
PubMed1997

Functional heterogeneity of leucine pools in human skeletal muscle.

Current models to measure muscle protein synthesis in humans assume a homogeneous intracellular amino acid pool. This assumption was tested by measuring the isotopic enrichment of leucine and its transamination product alpha-ketoisocaproate (KIC) in plasma and muscle tissue fluid and comparing them with that of leucyl-tRNA during a continuous infusion of L-[1-13C]leucine in 12 healthy subjects. Six subjects were studied twice while drinking a carbohydrate (0.42 kcal/kg) drink every 20 min for 11 h or the same volume of water. Six others took an isocaloric mixed meal providing 14 mg protein/kg every 20 min and water. Enrichment of plasma and tissue fluid KIC and plasma leucine was consistently higher than that of leucyl-tRNA and tissue fluid leucine (P < 0.01), whereas the enrichment of leucyl-tRNA was equivalent to that of tissue fluid leucine in all experiments. Furthermore, the ratio of enrichment of leucyl-tRNA to that of plasma leucine and KIC decreased after the mixed meal, whereas that of leucyl-tRNA to tissue fluid leucine remained constant. The enrichment of KIC was closer (approximately 17% lower) to that of plasma leucine than that of leucyl-tRNA (approximately 43% higher), indicating that the transamination pool derived more leucine from extracellular sources than the acylation pool. We conclude that the use of plasma KIC enrichment as a surrogate measure of leucyl-tRNA enrichment substantially underestimates muscle protein synthetic rates in humans, whereas tissue fluid leucine enrichment is a valid surrogate measure. In addition, the differences in enrichment of leucyl-tRNA and KIC support a regulated cytoplasmic trafficking of leucine in muscle cells.

Adult↗
PubMed1996

GroEL reversibly binds to, and causes rapid inactivation of, human carbonic anhydrase II at high temperatures.

The initial yield of reactivation of GuHCl denatured human carbonic anhydrase II does not change with temperature between 3 and 35 degrees C. At temperatures above 35 degrees C, the enzymatic activity is not stable, but decreases over time. If the bacterial chaperonin GroEL is present during reactivation, the initial yield is lower compared to the spontaneous reaction at temperatures of 35-50 degrees C. However, unlike the spontaneous reactivation, the enzymatic activity with time in the presence of GroEL. In the presence of GroEL, native HCA II incubated at elevated temperatures will rapidly loose enzymatic activity to the same value as during reactivation at that particular temperature; most of the activity will recover if the temperature is lowered when GroEL is present. It is evident that there is an equilibrium between an inactive intermediate of HCA II, probably bound to GroEL, and active enzyme. Furthermore, proline isomerization is part of the rate-limiting step of refolding even in the presence of GroEL, and it is very noteworthy that prolyl isomerase will influence the refolding of HCA II in the presence of GroEL.

Amino Acid Isomerases↗
PubMed1996

Phenylalanine kinetics in human adipose tissue.

Very little is known about the regulation of protein metabolism in adipose tissue. In this study systemic, adipose tissue, and forearm phenylalanine kinetics were determined in healthy postabsorptive volunteers before and during a 2-h glucose infusion (7 mg.kg-1.min-1). [3H]Phenylalanine was infused and blood was sampled from a radial artery, a subcutaneous abdominal vein, and a deep forearm vein. Adipose tissue and forearm blood flow were measured with 133Xe and plethysmography, respectively, and body fat mass was determined by dual energy x-ray absorptiometry. During glucose infusion, glucose concentration increased from 86 +/- 2 to 228 +/- 13 mg/dl and insulin concentration increased from 6.6 +/- 0.6 to 35.0 +/- 3.9 mU/liter, both P < 0.001. Systemic phenylalanine appearance decreased from 40.3 +/- 1.9 to 37.0 +/- 1.6 mumol/min during glucose infusion (P < 0.05). Baseline whole body adipose tissue phenylalanine release (5.2 +/- 1.4 mumol/min) was approximately 12% of systemic phenylalanine appearance and decreased (P < 0.05) to 2.3 +/- 0.9 mumol/min during glucose infusion. In contrast, phenylalanine release from the forearm did not change during glucose infusion. These results indicate that adipose tissue is a small but significant contributor to systemic phenylalanine appearance. Phenylalanine release from adipose tissue like lipolysis, is relatively sensitive to hyperinsulinemia.

Adipose Tissue↗
PubMed1996

Accuracy of machine milling and spark erosion with a CAD/CAM system.

A method for manufacturing crowns and fixed partial dentures based on CAD/CAM has been developed as an alternative to the lost wax technique and the casting of an alloy. In this process two steps are included: milling and spark erosion. The computer-assisted design (CAD) relies heavily on the accuracy of the milling and spark erosion processes to achieve a clinically acceptable restoration. These two processes must be able to produce the crown data generated in the CAD files. This study evaluated the accuracy of the Procera CAD/CAM system in creating specific geometric bodies that were compared with the known dimensions in the CAD files for these bodies. The manufacturing errors of milling (ellipse +/- 6.5 microm, square +/- 3.4 microm, and cylinder +/- 5.8 microm) and spark erosion (ellipse +/- 8.6 microm and square +/- 10.4 microm) were determined. The accuracy of this manufacturing process demonstrated that this system was capable of producing a crown with a clinically accepted range for marginal opening gap dimension of less than 100 microm.

Analysis of Variance↗
PubMed1996

A clinical evaluation of a glass ionomer cement as an orthodontic bonding adhesive compared with an acrylic resin.

Glass ionomer cement (GIC) has been suggested as an alternative to acrylic resin in bracket bonding because of its fluoride release. The aim of this clinical trial was to evaluate further the suitability of GIC as a bonding adhesive compared with an acrylic resin with regard to frequency of bracket failure, fracture modes and clean-up time after debonding. Two commercially available brackets were tested, one with a meshed foil base and the other with an integral base. A total of 60 patients, with a mean age of 13 years 7 months (range 10 years 8 months to 19 years 1 month) were consecutively selected. Brackets were bonded with a GIC (AquaCem, De Trey) and a no-mix diacrylate (Unite, Unitek Corp.) according to random assignment for each jaw. One group of patients (n = 30) was bonded with metal brackets with machine cut grooves in the base (DynaLock, Unitek). In the second group (n = 30) brackets with a meshed foil base (Unitwin, Unitek) were used. Bracket failure location during treatment was recorded as were fracture modes and time required for the clean-up of enamel surfaces at debonding. The frequency of failed brackets was higher with GIC (36 per cent) than with the diacrylate (15 per cent). Bracket failures for the cut groove base type occurred in 50 per cent with GIC and 23 per cent with the acrylic, meshed foil bases failed in 22 per cent GIC and in 7 per cent with the acrylic, respectively. The differences in failure between bracket types were significant at P < 0.001 for both bonding materials. Analysis of the fracture modes showed a small but noticeable difference in the strength of adhesion to the enamel surface, favouring GIC. Time required for the clean-up of enamel surfaces showed a significantly shorter debonding time for GIC. It is concluded that the use of a GIC for orthodontic bonding purposes considerably increases the risk of bond failures during treatment, especially in combination with a cut groove base type. One noticeable advantage with GIC bonding, however, is the shorter clean-up time for the enamel surfaces.

Acrylic Resins↗
PubMed1996

A 16S rRNA-based PCR assay for detection and identification of granulocytic Ehrlichia species in dogs, horses, and cattle.

A PCR-based assay was developed for detecting DNA of granulocytic ehrlichiae in blood samples from dogs, horses, and cattle, Primers were designed from 16S rRNA sequence information to specifically amplify DNA from a newly identified Swedish Ehrlichia species. The 16S rRNA nucleotide sequence of this Swedish species differs in only two and three positions from the sequences of Ehrlichia phagocytophila and Ehrlichia equi, respectively, which were also amplified by this PCR system. For evaluation, PCR results were compared with microscopic examination of stained blood smears for the detection of granulocytes containing ehrlichiae (morulae). Thirty-four of 36 microscopically positive samples were also positive by PCR, and 6 microscopically negative samples were negative by PCR as well. Six samples, in which morulae-like structures had been seen, were negative by PCR, also at a lower annealing temperature and when a reamplification of the first PCR products was performed. The identities of the PCR products from some canine and equine isolates were verified by direct DNA sequencing and were found to be identical with the Ehrlichia sequence found in these animal species that had been obtained earlier. The sequences of a segment of approximately 600 nucleotides from two bovine isolates were identical to that of E. phagocytophila, whereas the sequence of another bovine isolate differed in two positions from that of E. phagocytophila and in three positions from the sequences of the canine and equine isolates. Serum samples were analyzed by indirect fluorescent-antibody testing. Seventy-three percent of the animals which were positive by microscopy and PCR also had positive antibody titers. However, it was not possible to rely on a single serological result for diagnosis of present infection. It was, therefore, concluded that PCR was the most reliable method, useful in the clinical laboratory for specific and early diagnosis of granulocytic ehrlichiosis in animals.

Animals↗