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Biomedical subjects

H Andersson

Publications and source records attributed to H Andersson.

At least 55 records · Page 3Linked to original sources
PubMed1998

Photoperiodic effects on pubertal maturation of spermatogenesis, pituitary responsiveness to exogenous GnRH, and expression of boar taint in crossbred boars.

Forty-eight weaned, winter-born crossbred males (average age of 42 days) were exposed to either a natural photoperiod (January-June at 60 degrees N, Control) or one of two artificial photoperiods (1400 lx) in light-sealed rooms. The Spring/Summer group was exposed to an artificial photoperiod simulating conditions from the vernal equinox (mid-March) to August at 60 degrees N and the Autumn/Winter group to a photoperiod, simulating conditions from the autumnal equinox (mid-September) to February at 60 degrees N. Plasma samples were collected biweekly until the pigs were slaughtered, after reaching 115 kg, and analysed for testosterone, estrone sulfate, thyroxine and prolactin. Additionally, three animals per treatment (n = 9) were injected with gonadotropin-releasing hormone (GnRH) and plasma samples were collected every 15 min and analysed for luteinizing hormone and testosterone. Boar taint, carcass composition and reproductive traits were measured at slaughter. Live-weight gain from start to slaughter was lower among the Control animals compared with the Autumn/Winter and Spring/Summer animals. There was a peak in plasma testosterone in both the Spring/Summer and Autumn/Winter groups at 71 days of age, whereas plasma testosterone in the Control group remained at prepubertal levels. At 113 and 127 days of age, the Control group had somewhat higher testosterone levels than the Spring/Summer group, but at 141 days of age and on the day before slaughter, the Autumn/Winter group had a higher mean plasma testosterone concentration. There were no differences between treatments in the endocrine response to the GnRH challenge. Bulbourethral gland weight at slaughter was lower in the Spring/Summer group than in the Autumn/Winter group. The percentage of proximal cytoplasmic droplets was higher in the Spring/Summer group than in both the Control and Autumn/Winter groups. Spermatogenesis at the time of slaughter was clearly more mature in animals in the Autumn/Winter group than in those in the Spring/Summer and Control groups. Fat androstenone was lower in the Spring/Summer group than in the Control group. In the sensory evaluation, the Spring/Summer group had less boar taint than the Autumn/Winter group. Artificial short days with moderate initial changes in photoperiod, stimulated spermatogenesis compared with long days, in accordance with the pattern seen in European Wild Boars (Sus scrofa). Boar taint was also affected with higher scores in the Autumn/Winter group than in the Spring/Summer group, although this was not clearly indicated by the traditional measurements of boar taint-fat contents of androstenone and skatole.

Animals↗
PubMed1998

A study evaluating the efficacy and tolerability of tropisetron in combination with dexamethasone in the prevention of delayed platinum-induced nausea and emesis.

BACKGROUND: Chemotherapy-induced emesis is one of the most disturbing side effects of cancer therapy. Control of acute emesis has improved substantially during recent years, but control of delayed emesis and nausea remains a challenging problem. The role of 5-HT3 receptor antagonists in the treatment of delayed emesis is disputed. METHODS: Tropisetron, a highly specific 5-HT3 receptor antagonist, was compared (as an adjunct to dexamethasone) with placebo in a randomized, double blind, multicenter trial for the prevention of delayed emesis during platinum-containing chemotherapy. Three hundred chemotherapy-naive women with gynecologic malignancies were included. The cisplatin dose was in the range of 50-100 mg/m2. RESULTS: Acute emesis was prevented completely in 87% of patients and acute nausea in 77% of patients in the complete series. During the complete delayed period (Days 2-6), total control of emesis was achieved in 77% of the dexamethasone and tropisetron-treated patients and in 72% of the patients receiving dexamethasone and placebo (P = 0.2473). During the same period nausea was controlled completely in 42% of the dexamethasone and tropisetron group and in 41% of the dexamethasone and placebo group. On Day 3, complete protection from nausea was achieved in 65% of patients receiving tropisetron and in 51% of patients receiving placebo (P = 0.0304). Constipation occurred more frequently in the tropisetron group. CONCLUSIONS: Tropisetron added to dexamethasone improved control of delayed nausea on Day 3 compared with placebo. No significant differences were recorded regarding control of delayed emesis.

Adult↗
PubMed1998

Influence of artificial light regimens on sexual maturation and boar taint in entire male pigs.

To determine if artificial light regimens could influence sexual maturation and boar-taint factors in entire male pigs, 48 weaned, winter-born crossbred males (52-64 days old) were exposed to either a natural photoperiod (January-June, 60 degrees N, Control, n= 16) or to one of two artificial photoperiods (1400 1x) in light-sealed rooms. We exposed the Spring group to an increasing artificial photoperiod (January - June, 60 degrees N, n=16) and the Autumn group to a decreasing one (July-December, 60 degrees N, n = 16). Plasma samples were collected bi-weekly until the pigs were slaughtered, after reaching 115 kg. Boar taint, carcass composition and reproductive traits were measured at slaughter. Plasma testosterone increased earlier in the Autumn group than in the Control and Spring groups, but the difference was only transient. Estrone sulfate concentrations remained low in the Autumn group, whereas they increased in the Control and Spring groups, indicating a lack of synchrony between testicular androgen and estrogen production in the Autumn group. In the beginning of the study, when the Autumn group was subjected to long days, plasma prolactin was higher in the Autumn group than in the Spring group, but the relation was reversed 14 weeks later when the spring group was exposed to long days. Weight of reproductive organs (epididymidal weight and the total weight of the testes, epididymides and the bulbourethral glands relative to carcass weight) were lower in the Autumn and Spring groups than in the Control group. The Spring and Autumn groups had lower concentrations of skatole in fat compared with the Control group, whereas no clear difference was detected between groups in concentrations of androsterone in fat or in the sensory evaluation of boar taint. Estimated lean meat percentage was lower among animals in both the Autumn and Spring groups compared with the Control group. This study shows that photoperiod can influence male pubertal development and boar-taint factors in the domestic pig.

Adipose Tissue↗
PubMed1998

Neurotoxic effects of fractionated diesel exhausts following microinjections in rat hippocampus and striatum.

Exhaust emissions from a heavy-duty diesel vehicle, separated into particulate and semivolatile phases and thereafter fractionated according to polarity, were studied in the adult rat brain after intracranial microinjections using cresyl violet staining and immunohistochemistry. Intrastriatal as well as intrahippocampal injections of particulate fractions III [containing mononitro-polycyclic aromatic hydrocarbon (PAH)], IV (dinitro-PAH and quinones) and V (polar material) and of semivolatile fractions IV and V, in amounts corresponding to a driven length of 19.5 m, caused major lesions with tissue loss and disappearance of immunoreactivity for glial fibrillary acidic protein, tyrosine hydroxylase, and acetylcholine esterase. Particulate fractions I ("light" aliphatic hydrocarbons) and II ("heavy" aliphatic hydrocarbons and PAH) and semivolatile fraction III produced smaller lesions; semivolatile fractions I and II led to lesions equivalent to those of the vehicle dimethyl sulfoxide alone. Microinjected doses of particulate fractions III or IV corresponding to driven lengths of 2.0 and 9.8 m produced a variable lesion. Thus, fractions containing nitro-derivatives of PAH, quinones, and polar material caused the greatest damage after intracranial injections. It is concluded that intracerebral microinjections of fractionated motor vehicle exhausts provide a method for systematic testing of direct neurotoxicity.

Animals↗
PubMed1998

Sugar beet fiber in formula diet reduces postprandial blood glucose, serum insulin and serum hydroxyproline.

OBJECTIVE: The object of the study was to investigate the effects of sugar beet fiber in formula diet on blood glucose, serum insulin and serum hydroxyproline in humans. DESIGN: Two formula test meals with and without 7 g of sugar beet fiber, namely 5.1 g total dietary fiber, were ingested on two mornings, in random order, by the subjects. SETTING: The test meals were served in a clinic to the subjects after a 12 h fast. SUBJECTS: Fifteen healthy male human volunteers (mean age 25 y, range 21-42) registered to participate in the study after an announcement. METHODS: The test meals of formulas contained similar amounts of nutrients and gave total energy of 1778 kJ (425 kcal). Blood samples were drawn before and after the test meals. The total test time from the start of ingestion of the meal was 155 min. RESULTS: The formula with sugar beet fiber reduced the postprandial blood glucose response (P < 0.05), serum insulin response (P < 0.025) and serum hydroxyproline response (P < 0.025), compared with the formula without fiber. CONCLUSION: Sugar beet fiber in a formula could thus reduce hyperglycemia in enteral nutrition and be useful in therapeutic liquid and formula diets. Sugar beet fiber was shown to tolerate preparation for canning well, namely homogenization and heating, and to be capable of diminishing the glycemic responses in the relatively small amount used.

Adult↗
PubMed1998

Retrograded high-amylose corn starch reduces cholic acid excretion from the small bowel in ileostomy subjects.

OBJECTIVE: To study the short-term effect of resistant starch (RS) from retrograded high-amylose corn starch (HACS) on the excretion of bile acids and nutrients from the small bowel in humans. DESIGN: Seven healthy ileostomists were given a controlled, constant diet during three days. On days 2 and 3, 100 g/d of one of two test-products--drum-dried ordinary corn starch and autoclaved retrograded HACS, providing 5 and 39 g RS/d, respectively--was given, in random order. Ileostomy effluents were collected for 24 h per day and analysed for wet weight, dry weight, energy, bile acids and nutrients. SETTINGS: In-patient study at the metabolic ward, Department of Clinical Nutrition, Sahlgrenska University Hospital, Göteborg. RESULTS: Consumption of retrograded HACS caused (1) a 42% lower mean excretion of cholic acid (P = 0.024); (2) a 42% lower mean wet weight concentration of bile acids (P < 0.001); (3) a 70% increased excretion of dry weight (P = 0.001); and (4) a 41% increased excretion of energy (P= 0.036) compared with consumption of drum-dried ordinary corn starch. CONCLUSION: The reduced ileal excretion and concentration of cholic acid would be protective regarding colon cancer risk in addition to the increased fermentation substrate provided by RS and other energy-yielding components.

Adult↗
PubMed1998

Effect of semi-annual applications of a chlorhexidine/fluoride varnish mixture on approximal caries incidence in schoolchildren. A three-year radiographic study.

Development and progression of approximal caries is still difficult to prevent and control even in societies with declining caries prevalence. In this study, a test group of 115 12-yr old children were treated semi-annually with a mixture (1:1) of a varnish containing 0.1% F (Fluor Protector) and 1.0% chlorhexidine (Cervitec). A reference group of 104 children received fluoride varnish treatment (Fluor Protector) semi-annually. Approximal caries was recorded from bitewing radiographs at baseline and after 3 yr. At baseline, total decayed and filled surfaces (DFS) including enamel caries were 1.79+/-2.36 in the reference group and 2.0+/-2.77 in the test group. After 3 yr, the mean approximal caries incidence including enamel caries was 3.01+/-3.74 and 3.78+/-4.32, respectively. The differences at baseline as well as after 3 yr were not statistically significant. The results showed that both groups had a comparatively low incidence of approximal caries during the experimental period, and suggest that a mixture of fluoride and antibacterial varnish had no additional preventive effect on approximal caries incidence compared with fluoride varnish treatments alone.

Anti-Infective Agents, Local↗
PubMed1998

Autofluorescence of living cells.

We have investigated the autofluorescence of viable mammalian cells (DU-145 and V79) with a confocal laser scanning microscope equipped with a UV laser. Our aim was to investigate the autofluorescence dependence on different treatments in mitochondria and lysosomes by using different reagents and to improve the confocal laser scanning microscope image quality by deconvolution. The following conclusions were drawn from the results: (1) not all of the autofluorescence comes from mitochondria; (2) one can significantly affect the signal which comes from the mitochondria; (3) the other organelles involved are probably lysosomes; (4) it is harder to affect the autofluorescence signal from the lysosomes than that from the mitochondria, and (5) deconvoluted autofluorescence images provide better information than undeconvoluted ones.

Animals↗
PubMed1998

Long-term chemotherapy of ovarian cancer: two case reports.

The treatment period of patients with advanced ovarian cancer is generally limited to about six months and maintenance chemotherapy is seldom used. The present report describes two women given chemotherapy continuously for several years with apparently good efficacy and acceptable toxicity.

Aged↗
PubMed1998

Widespread musculoskeletal chronic pain associated with smoking. An epidemiological study in a general rural population.

Data on smoking and pain symptoms from a random sample (n = 1806) of a general population were used to evaluate the association between chronic pain at various locations and smoking. In both genders current smoking was associated with reports of increased pain in low back, neck and with multiple locations. In a multiple logistic regression analysis current smoking was associated with an increase in widespread chronic musculoskeletal pain (OR 1.60, CI 1.04-2.46, in relation to non-smokers) and chronic low back pain (OR 1.58, CI 1.13-2.20, in relation to non-smokers). A dose-response relationship was found between the daily cigarette consumption and the prevalence of chronic low back pain. Smoking is associated not only with low back pain but also with chronic widespread musculoskeletal pain. No conclusive decrease in pain prevalence was found after quitting smoking. Further studies are necessary to elucidate an aetiologic relationship between smoking and chronic pain.

Adult↗
PubMed1998

Approximal caries development following intensive fluoride mouthrinsing in teenagers. A 3-year radiographic study.

Caries development on approximal surfaces was studied in 139 adolescents for a period of 3 yr. A test group was randomly sampled (n=69) and subjected to a new intensive mode of fluoride (F) mouthrinsings using 10 ml of 0.045% NaF neutral solution once a day for 3 d, twice a year in all, i.e., 6 rinses per year. A control group (n = 70) rinsed in a similar mode using fluoride-free tap water. The two groups received the same basic prophylactic program during the trial. Detection of approximal caries lesions and fillings was based on bitewing radiographs at baseline and after 3 yr. The test group developed an average of 2.75 + 4.76 (mean +/- SD) approximal DFS compared with 3.21 + 4.74 DFS in the control group (n.s.). However, among those teenagers who were caries free (DFS = 0) at baseline, the incidence of approximal carious and filled surfaces was 1.76+/-4.52 in the F-rinsing group (n = 26) compared with 2.76+/-5.01 DFS in the control group (n = 32), a 36% caries reduction which was statistically significant. The intensified mouthrinsing procedure seems to be a promising prophylactic mode for collective caries prevention.

Adolescent↗
PubMed1997

Plant-derived amino acids increase hippocampal BDNF, NGF, c-fos and hsp70 mRNAs.

Early alterations in mRNAs encoding neurotrophins and stress proteins were investigated following intracerebroventricular injections of beta-N-oxalylamino-L-alanine (BOAA) and beta-N-methylamino-L-alanine (BMAA) in adult rats using in situ hybridization. Major increases in heat-shock protein 70, c-fos and brain-derived neurotrophic factor (BDNF) mRNAs were seen in hippocampus 1 h after BOAA or BMAA injections. Nerve growth factor mRNA was profoundly increased in the dentate gyrus (DG) after both treatments. Four hours after BMAA injections increased hybridization to BDNF mRNA was still seen in hippocampus, in parallel with reduced neurotrophin-3 expression in the DG. These alterations are in accordance with previous findings of BOAA and BMAA as potent glutamate receptor agonists.

Amino Acids, Diamino↗
PubMed1997

Reverse transcriptase and corresponding activity-blocking antibody for monitoring SIVsm infection in macaques.

A nonradioactive reverse transcriptase (RT) assay was used to measure RT activity in serum during the viremia peak associated with primary infection and for measuring the generation and maintenance of RT activity-blocking antibody (RTb-ab) titers during and after seroconversion in SIV-infected macaques. The RT assay was compared to an antigen capture immunoassay designed for HIV-2/SIVsm and was found to be approximately 40 times more sensitive in detecting SIVsm in serum from infected macaques. The RT assay detected RT activity in serum corresponding to levels from 3 pg/ml. Earliest detection of viral replication using the RT assay was on day 6-8, with a peak at day 10 (up to 8000 pg/ml). The earliest detection of RTb-ab was seen on day 17-23, with established RTb-ab titers by day 29, followed by increasing titers of 15,000-120,000 by day 62-77. The usefulness of RT and RTb-ab for monitoring the course of SIV infection in monkey models is discussed.

Animals↗
PubMed1997

Topological rules for membrane protein assembly in eukaryotic cells.

Insertion into the endoplasmic reticulum membrane of model proteins with one, two, and four transmembrane segments and different distributions of positively charged residues in the N-terminal tail and the polar loops has been studied both in vitro and in vivo. Membrane insertion of these same constructs has previously been analyzed in Escherichia coli, thus making possible a detailed comparison between the topological rules for membrane protein assembly in prokaryotic and eukaryotic cells. In general, we find that positively charged residues have similar effects on the membrane topology in both systems when they are placed in the N-terminal tail but that the effects of charged residues in internal loops clearly differ. Our results rule out a sequential start-stop transfer model where successive hydrophobic segments insert with alternating orientations starting from the most N-terminal one as the only mechanism for membrane protein insertion in eukaryotic cells.

Amino Acid Sequence↗
PubMed1997

Downregulation of brain-derived neurotrophic factor mRNA in adult rat brain after acute administration of methylmercury.

Conventionally, assessment of the neurotoxicity of environmental pollutants relies on high-dosage treatment and nonspecific end points. In the present study, the early temporal and regional alterations in the mRNAs of neurotrophins were investigated following subtoxic doses of methylmercury (MeHg) in adult Sprague-Dawley rats using in situ hybridization histochemistry and phosphoimaging evaluation. Decreases in brain-derived neurotrophic (BDNF) mRNA labeling intensities were seen in the dentate gyrus (DG; 44% of controls), and in the CA1 (72% of controls) and CA3c (70% of controls) cell layers of hippocampus after 8 mg MeHg/kg (ip) at 4 h, and at 1 h only in the DG. The decrease in BDNF mRNA expression in the DG was dose-dependent. At 3 d, regional levels had recovered. No significant changes could be detected in mRNA levels of the BDNF high-affinity receptor trkB or neurotrophin-3 mRNA at either 1 h, 4 h, or 3 d. Cresyl violet staining and GFAP immunohistochemistry did not reveal any major neuropathology in hippocampus at 2 wk. Thus, MeHg causes specific downregulation of BDNF mRNA, unlike many other perturbations of central nervous system homeostasis that have been shown to lead to upregulation of this mRNA.

Animals↗