Altered medial versus lateral hamstring muscle activity during hop testing in female athletes 1-6 years after anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to assess activation patterns of medial (MH) versus lateral (LH) hamstrings in female athletes who had undergone ACL reconstruction (ACLR) using a hamstrings-graft during single-limb functional testing. METHODS: Eighteen athletes (1-6 years since ACLR) and 18 healthy controls were recruited from the Icelandic women's top divisions in football, handball, and basketball. Activation of the MH and LH was monitored bilaterally using surface electromyography. Peak activation of the normalized signal was identified for two phases of the single-limb crossover (SLC) hop test and performance (distance jumped) registered. Self-reported knee symptoms and function were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS). A repeated measures general linear model was used for main statistical data analyses, comparing variables of interests between limbs (within-subjects factor) and between groups. RESULTS: ACLR athletes had worse KOOS-symptoms scores (p < 0.05) than controls, while hop distance was equal. Overall, MH and LH muscle activation levels differed between the two phases of the SLC hop test (p < 0.05). Moreover, inter-limb differences in MH and LH activity were identified between groups (p < 0.05), mainly explained by greater LH than MH activation in the uninjured limb of ACLR athletes. CONCLUSION: One to 6 years after ACLR, female athletes performed on par with uninjured controls, but demonstrated inter-limb differences in muscle activation patterns of the hamstrings that were not evident in controls. This may be an important factor to consider during postsurgical rehabilitation in order to lower the risk of a second injury. LEVEL OF EVIDENCE: III.

Importance of the lactate anion in control of breathing.

The purpose of this study was to examine the effects of raising the arterial La- and K+ levels on minute ventilation (VE) in rats. Either La- or KCl solutions were infused in anesthetized spontaneously breathing Wistar rats to raise the respective ion arterial concentration ([La-] and [K+]) gradually to levels similar to those observed during strenuous exercise. VE, blood pressure, and heart rate were recorded continuously, and arterial [La-], [K+], pH, and blood gases were repeatedly measured from blood samples. To prevent changes in pH during the La- infusions, a solution of sodium lactate and lactic acid was used. Raising [La-] to 13.2 +/- 0.6 (SE) mM induced a 47.0 +/- 4.0% increase in VE without any concomitant changes in either pH or PCO2. Raising [K+] to 7.8 +/- 0.11 mM resulted in a 20.3 +/- 5.28% increase in VE without changes in pH. Thus our results show that La- itself, apart from lactic acidosis, may be important in increasing VE during strenuous exercise, and we confirm earlier results regarding the role of arterial [K+] in the control of VE during exercise.

Olfactory sensitivity and specificity of Arctic char, Salvelinus alpinus, to a putative male pheromone, prostaglandin f(2)alpha.

Actively spawning male Arctic char, Salvelinus alpinus, release immunoreactive F-prostaglandins into the water that attract ovulated females and elicit spawning behaviour. To investigate a possible role played by the olfactory system, we determined the sensitivity and specificity of the char to prostaglandins by the electro-olfactogram (EOG) using a newly devised stimulatory apparatus. Of 18 prostaglandins tested, PGF(2)alpha and two synthetic analogues, 16,16-dimethyl-PGF(2)alpha and U-46619, were detected at threshold concentrations of 0.5-1.0 x 10(-11) M, and at a concentration of 10(-8) M evoked an EOG response equivalent to that of 10(-5) M L-serine. Olfactory nerve twig recordings further demonstrated that the EOG responses were transduced into nerve impulses and transmitted to the brain. No difference was found in the responses between sexes and maturational stages. We conclude that PGF(2)alpha is a candidate of the male pheromone of Arctic char, supporting our previous behavioural studies.

Chemical control of Penthaleus major (Acari: Prostigmata) in hayfields in Iceland.

The plant parasitic mite Penthaleus major (Dugès) occurs as a pest on perennial grasses in hayfields in Iceland, northern Norway, and southern Greenland. In these areas it appears as a summer phenomenon, contrary to more southern locations, where it appears as a pest on winter crops. Up to 500 individuals of P. major were collected per day in pitfall traps. Spring application of 44 ml/ha of permethrin and 5 ml of deltamethrin significantly reduced but did not eliminate the populations of P. major the following weeks. In addition to this immediate effect, spring application also decreased the mite populations in the fall and even the following spring. Additional effects might be obtained by earlier spring application. Despite a significant reduction in mite populations and reduction in visible plant damage, significant differences on dry matter yield were rarely registered. A side effect of application was a small but significant reduction in potassium-content of the yield, and the reduction in mite population was accompanied by a corresponding reduction in the number of spiders.

Tracking of overweight from early childhood to adolescence in cohorts born 1988 and 1994: overweight in a high birth weight population.

OBJECTIVE: To investigate the prevalence and tracking of overweight and obesity in childhood cohorts born 1988 and 1994 in a population of high birth weight. SUBJECTS: Icelandic cohorts born in 1988 and 1994. MATERIALS AND METHODS: Out of 1328, 9- and 15-year-old children from 18 randomly selected schools all over Iceland, 934 participated (71%). Height and mass were measured by the investigators. Also, height and mass at birth, and at age 2.5, 6, 9, and 12 years, were collected from maternity wards and school health registers. RESULTS: The prevalence of overweight children ranged from 10.1% for 2.5-year-olds to 18.7% for 9-year-olds. No difference was observed between the two cohorts or sex. The prevalence of obesity in the 1994 cohort (4.3%) was significantly higher (P = 0.01) at age 6 years, compared to the 1988 cohort (1.1%). The children who were overweight at age 2.5 years were more likely to be overweight at age 6 (OR=12.2) and 9 years (OR=4.9), but not significantly at age 12 or 15 years, compared with normal weight 2.5-year-olds. Overweight children at age 6 or 9 years were much more likely (OR 10.4 and OR 18.6, respectively) to be overweight at age 15 years compared to their normal weight peers. Of overweight 6-year-olds, 51% were overweight at 15 years, and were about one-third of all overweight children at that age. The children that weighed above the 85th percentile at birth were more likely than the other children to be overweight at the age of 6 years (OR = 1.8), 9 years (OR = 2.1), and 15 (OR = 2.0) years. CONCLUSION: The results show high prevalence of overweight and obesity even before the start of compulsory schooling. Approximately, 51% of overweight 6-year-olds were still overweight after puberty. Therefore, preschool overweight prevention, along with prevention at school age, seems to be of uttermost importance.

Malignant nasopharyngeal tumours in Iceland.

From 1965 to 1990, 46 cases of malignant nasopharyngeal tumours were diagnosed in Iceland. The incidence rate is as low as in other Western countries, 0.6/100,000 per year. Histo-pathological diagnosis were as follows: Undifferentiated carcinoma 45%; squamous cell carcinoma 30%; non-keratinizing carcinoma 7%; and plasmacytoma 9%; lymphoma 7%; rhabdomyosarcoma 2%. Four per cent were diagnosed at stage I, 13% at stage II, 29% at stage III and 54% at stage IV. The overall crude survival at 10 years from diagnosis was 28.3%. The following factors were found to have a prognostic value: Stage of disease, size of tumour (T-classification) and age at diagnosis. Nodal stage (N-classification) alone and sex were not found to be prognostic factors. There was no difference in survival among the different WHO types of cancer. Patients with carcinoma were all treated with radiotherapy. The survival of those who received more than 60 Gy was better than of those who received 60 Gy or less (p = 0.04).

Combined irradiation and three-drug chemotherapy in inoperable colorectal carcinoma.

Forty patients with inoperable or not radically resected tumours in the rectum or rectosigmoideum were treated with irradiation combined with 5-fluorouracil, methotrexate and cyclophosphamide. The acute toxicity was moderate, but 3 patients developed late complications such as fibrosis and fistulation in the irradiated area. Twenty-one patients had a measurable tumour within the radiation fields and were included in the evaluation of the tumour response. Of these patients 8 achieved complete and 5 partial tumour remission. Nevertheless, it is emphasized that this treatment cannot be recommended because of severe complications observed in a following randomized series of patients receiving irradiation combined with 5-fluorouracil and methotrexate.

Resources and productivity in radiation oncology in Denmark, Finland, Iceland, Norway and Sweden during 1987.

Data concerning megavoltage equipment and use of megavoltage external beams in cancer management during 1987 in Denmark, Finland, Iceland, Norway, and Sweden were collected from all 37 centres serving a population of 23 million in these countries. Population per Linear Accelerator Equivalent (LAE) unit ranged from 0.30 million/LAE unit (Denmark) to 0.19 million/LAE unit (Sweden). The number of field treatments were 227,548 (Denmark), 259,917 (Finland), 10,426 (Iceland), 147,960 (Norway) and 490,126 (Sweden). The number of field treatments per million population per year ranged from 35,229 (Norway) to 58,438 (Sweden). The number of field treatments per LAE unit/year ranged from 13,192 (Denmark) to 9,546 (Norway). The fraction of cancer patients receiving megavoltage radiotherapy in 1987 out of all newly diagnosed cancer patients during 1987 was 24% in Denmark, 37% in Iceland, 25% in Norway, and 34% in Finland and Sweden. We conclude that Denmark and Norway probably did not provide adequate levels of radiotherapy for their cancer patients during 1987.

[DNA flow cytometry is a useful prognostic guide in the treatment of breast cancer.].

It is widely agreed that the presence or absence of axillary lymph-node involvement (N) is the most reliable predictor of relapse or survival in breast cancer, together with tumor size (T) and the presence or absence of distant metastasis (M). These prognostic factors are the cornerstones of the TNM staging system. The aim of the present study was to ascertain, in all patients diagnosed with invasive primary breast cancer in Iceland during the years 1981-84 (n=347), whether flow cytometric DNA analysis of ploidy status and fraction of cells in the S-phase contribute prognostic information, addi nottional to that obtained with TNM staging variables. Paraffin fixed tumor material was available from 340 patients (98%) and DNA ploidy and S-phase fraction was assessed with flow cytometry. DNA ploidy could be analysed in 98% of tumor samples (n=334), of which 114 (34%) were diploid and 220 (66%) non-diploid. S-phase fraction could be analysed in 97% of the tumor samples (n=329), the median S-phase value was 7.0%, and was higher in non-diploid than diploid tumors (p<0.0001, 9.3% vs. 2.7%). Median duration of patient follow-up was 7.5 years. The disease-free survival at that point of time was 15% higher in patients with diploid tumors than non-diploid ones (p=0.004, 69% vs 54%). Similar survival comparison in relation to S-phase fraction was 30% when the median S-phase value was used as cut-off point (p<0.0001, S-phase<7.0% being 74% vs. S-phase ;7.0% being 44%). Multivariate analyses with regard to breast cancer survival and disease-free survival, which included both ploidy status and S-phase categories adjusting for age, tumor size and lymph node involvement, showed the S-phase value categories to be independent prognostic variables (p<0.0001). Patients with high S-phase tumors had a three-fold higher risk of recurrence than patients with low S-phase tumors. Ploidy status was not an independent prognostic variable, if however the S-phase categories were excluded from analysis, ploidy status was on the borderline of being an independent variable (p=0.09). In node-negative patients the S-phase fraction was the only useful variable in determining prognosis. We conclude that the S-phase value is a useful prognostic guide for the clinician and will be used for this purpose in the treatment of breast cancer in Iceland.