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Biomedical subjects

H Andersson

Publications and source records attributed to H Andersson.

At least 253 records · Page 14Linked to original sources

A threshold limit theorem for a multitype epidemic model.

The asymptotic final size distribution of a multitype Martin-Löf process, a discrete-time SIR model for the spread of an infectious disease in a closed multitype population, is derived for the case of large total population size. When all subgroups are of comparable size and the infection pattern is irreducible, a threshold behavior is obtained, and the asymptomatic distributions for small and large outbreaks can be found. As an important corollary we get a threshold limit theorem for a class of continuous-time SIR models with several types.

Communicable Diseases↗

Low-level cadmium exposure of lactating rats causes alterations in brain serotonin levels in the offspring.

Effects on monoaminergic and cholinergic transmitter systems as well as neurotrophins were characterized in developing Sprague-Dawley rats directly exposed to 5 ppm cadmium in the drinking water or indirectly via exposed dams. Cadmium was given to dams during the lactation period, from parturition to postnatal day 17, and/or to the offspring until postnatal day 42. Cresyl violet staining and glial fibrillary acidic protein immunohistochemistry did not reveal any obvious neuropathology after cadmium exposure. Following high-power microwave fixation, concentrations of acetylcholine (ACh) and monoamines were determined in cerebral cortex, striatum, and hippocampus using HPLC with electro-chemical detection. ACh, dopamine, and noradrenaline levels were not significantly affected after the different cadmium exposures. Cortical levels of serotonin were significantly reduced in rats exposed to cadmium during lactation as well as in rats exposed to cadmium during both lactation and postweaning. A major decrease in 5-hydroxyindoleacetic acid was found in cortex and hippocampus in rats exposed to cadmium during lactation. The regional characteristics of cadmium toxicity as reflected in changes of neurotrophins were studied using in situ hybridization histochemistry with oligonucleotide probes and phosphoimaging evaluation. No significant changes in the mRNA expression of brain-derived neurotrophic factor (BDNF), neurotrophin-3, and the high-affinity tyrosine kinase receptor of BDNF, trkB, were detected. The present results demonstrate that exposure to levels of cadmium as low as 5 ppm in the drinking water leads to neurochemical disturbances of the serotonergic system in the offspring during the lactational period.

Acetylcholine↗

Influence of nutrition on testicular growth in Corriedale rams during spring.

To study the effect of nutrition on spring testicular growth, four adult Corriedale rams were allowed to graze enough to maintain weight (maintenance group), while another four rams, in addition to forage, received a supplemental grain-based ration (increased gradually from 100 to 400 g during the first 5 d and kept at 400 g thereafter) daily for 63 d (supplemented group). Body weight, scrotal circumference, inguinal hyperaemia and testicular consistency were assessed. Blood concentrations of LH and testosterone were measured for 24 h on the day before supplementation began, the day after the animals were fed 200 and 400 g, and 12 and 28 d after animals began to receive the supplement. On these occasions blood contents of non-esterified free fatty acid and beta-hydroxybutyrate were measured when animals were fasting. Supplemented feeding increased body weight within 21 d and scrotal circumference within 35 d (P < 0.01). Scrotal circumference also increased in rams of the maintenance group (P < 0.01) but a lower rate than the supplemented group (P < 0.001). In both groups, testicular consistency and inguinal hyperaemia increased (P < 0.01). In the supplemented group a transient increase (P < 0.01) in LH pulsatility occurred the day after rams had received the full supplement (400 g) and 5 d later (day 12). However, no difference was found in total testosterone release between groups. In conclusion, improved nutrition accelerated the testicular growth in spring, although only a transient increase in LH pulsatility was observed. The scrotal circumference of rams kept on maintenance diet did also increase, which indicates that nutrition is not the only environmental cue responsible for the vernal testicular redevelopment in Corriedale rams.

3-Hydroxybutyric Acid↗

Effect of quarterly treatments with a chlorhexidine and a fluoride varnish on approximal caries in caries-susceptible teenagers: a 3-year clinical study.

The aim of this study was to compare the effect of two different dental varnishes on approximal caries incidence in teenagers with proven caries susceptibility during a 3-year period. Two hundred 13- to 14-year-old subjects exhibiting at least two approximal enamel caries lesions were selected to take part in the study. One hundred and eighty subjects participated after informed consent and were randomly assigned to two equally sized groups. One group was treated with a fluoride varnish (FV, Fluor Protector) containing 0.1% F every 3rd month and the participants of the other group were treated in the same mode with a chlorhexidine varnish (CV, Cervitec((R))) containing 1% chlorhexidine and 1% thymol. In total, each subject was treated 12 times during the experimental period. Approximal caries including enamel lesions (DMFS(appr)) were recorded from four bitewing radiographs exposed at the start and end of the study. The mean (+/-SD) caries prevalence at baseline was 2.2+/-3.4 in the FV group and 2.5+/-4.0 in the CV group. After 3 years, the average approximal caries incidence was 2.7+/-3.1 and 3.1+/-3.5 in the FV and CV groups, respectively. The differences at baseline and after 3 years were not statistically significant. In conclusion, treatments every 3rd month with either a fluoride- or a chlorhexidine/thymol-containing varnish showed a promising effect with low approximal caries incidence and progression in teenagers with proven caries susceptibility.

Adolescent↗

A randomised, double-blind, parallel-group study to compare the efficacy and safety of ondansetron (GR38032F) plus dexamethasone with metoclopramide plus dexamethasone in the prophylaxis of nausea and emesis induced by carboplatin chemotherapy.

A double-blind, parallel-group study in 189 ovarian cancer patients compared the efficacy of ondansetron 8 mg i.v. (OND) and metoclopramide 60 mg i.v. (MET) both in combination with dexamethasone 20 mg i.v. in the prevention of carboplatin-induced emesis. On day 1, complete or major control of emesis (0-2 emetic episodes) was observed in 97% patients from the OND group compared with 74% patients from the MET group (p < 0.001). Similarly, a worst-day analysis over days 1-3 showed complete or major control of emesis in 87% patients (OND) compared wth 66% patients (MET) (p < 0.001). Similar findings in favour of the OND group were observed for nausea grade on day 1 and the worst-day grade during days 1-3. OND was better tolerated than MET. Fewer patients from the OND group (13%) reported adverse events compared with the MET group (21%). Extrapyramidal type symptoms were observed in 6 (6%) patients from the MET group (paraesthesia, involuntary movement of the jaw and tongue, and restlessness), compared with none from the OND group. Ondansetron plus dexamethasone is a highly effective and well-tolerated treatment and is significantly superior to metoclopramide plus dexamethasone in the prevention of carboplatin-induced emesis.

Adult↗

Energy and mineral utilization from a peptide-based elemental diet and a polymeric enteral diet given to ileostomists in the early postoperative course.

Small intestinal absorption was studied in 12 patients receiving enteral nutrition in the immediate postoperative period after colorectal surgery including construction of an ileostomy. Seven patients were given a peptide-based, low osmolality elementary diet and five patients were given a polymeric diet. Comparisons between the intake and ileal excretion showed on both diets a high utilization of energy, fat, and nitrogen as well as of calcium, phosphorus, magnesium, zinc, and iron. From a nutritional point of view a polymeric diet could thus replace an elementary diet in the immediate postoperative course.

Adult↗

SecA-dependence of the translocation of a large periplasmic loop in the Escherichia coli MalF inner membrane protein is a function of sequence context.

We have analysed the translocation of a large periplasmic loop in the Escherichia coli MalF inner membrane protein when placed in different sequence contexts and under conditions when the function of the SecA protein is inhibited. The results show that the degree of SecA-dependence varies with sequence context: while translocation of the large loop in its normal context is only minimally affected by SecA inhibition, translocation is much more sensitive to SecA inhibition when the loop is placed in the context of other inner membrane proteins. Conversely, when the large MalF loop is replaced by segments from other proteins, translocation of those segments is again very sensitive to SecA inhibition. Thus, SecA-dependence is not an all-or-none phenomenon and is not only a simple function of, e.g. the length of a translocated segment or the hydrophobicity of the flanking transmembrane segments.

ATP-Binding Cassette Transporters↗

Radioimmunotherapy of nude mice with intraperitoneally growing ovarian cancer xenograft utilizing 211At-labelled monoclonal antibody MOv18.

The aim of this study was to investigate the therapeutic efficacy of 211At-labelled monoclonal antibody given intraperitoneally to nude mice with intraperitoneal growth of a human ovarian cancer cell line. Female nude mice were inoculated intraperitoneally with 1 x 10(7) cells of the human ovarian cancer cell line NIH:OVCAR 3. After about two weeks they were injected with the 211At-labelled specific monoclonal antibody MOv18 intraperitoneally. For comparison, other groups of mice were given the same labelled antibody intravenously, 211At-labelled unspecific antibody C242 intraperitoneally or unalbelled MOv18 intraperitoneally. Six weeks later the animals were sacrificed and the occurrence of tumour and ascites was determined. When the mice were treated with 211At-labelled MOv18 intraperitoneally 9 out of 10 were apparently free of both ascites and tumour compared to none of the mice given unlabelled antibody. 211At-labelled MOv18 given intravenously or 211At-labelled unspecific antibody given intraperitoneally were less effective. Regional radioimmunotherapy with the alpa-emitter 211Astatine seems to be an effective treatment of nude mice with intraperitoneally growing human ovarian cancer. Hopefully this treatment can be given in an adjuvant setting to women with minimal residual ovarian cancer in the future.

Animals↗

In vitro effects of free 211At,211At-albumin and 211At-monoclonal antibody compared to external photon irradiation on two human cancer cell lines.

BACKGROUND: The aim of this study was to perform various 211At irradiations of importance for the evaluation of 211At-radioimmunotherapy, and compare the effect with that of low linear energy transfer (LET) radiation. MATERIALS AND METHODS: All irradiations were performed on low-concentration single-cell suspensions. Growth assays using 96-well plates were used to estimate apparent cell survival. Centrifuge tube filters were used to estimate the cell uptake and binding of 211At. RESULTS: A relative biological effect (RBE) of 12 +/- 2 (Colo-205) and 5.3 +/- 0.7 (OVCAR-3) was found from 211At-albumin irradiations. There was a 174 +/- 28 times higher free 211At concentration in the cell fraction than in the surrounding medium. For 211At-MAb, an 8,000-30,000 times higher concentration in the cell fraction was achieved, compared to the medium. Corrected for the uptake, an average of 31 +/- 2 ([211At]-astatine) or 26 +/- 5 ([211At]-MAb) decays per cell were required for 37% survival of Colo-205 cells. An average of 19 +/- 3 decays ([211At]-astatine) were required per OVCAR-3 cell. CONCLUSIONS: Cell uptake and binding of 211At was unexpectedly high, possibly favouring its therapeutic use. The binding is probably to the cell surface. The RBE is 5.3 +/- 0.7 for OVCAR-3 and 12 +/- 2 for Colo-205 cells.

Antibodies, Monoclonal↗