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Biomedical subjects

A Oksanen

Publications and source records attributed to A Oksanen.

11 recordsLinked to original sources

Oral and parenteral administration of ivermectin to reindeer.

The anti-parasitic effect of the orally administered paste formulation of ivermectin (Ivomec) in reindeer was evaluated by means of a trial designed to compare the efficacies of orally and s.c. administered ivermectin at the same dosage (0.2 mg kg-1 body weight) in naturally infected adult reindeer (n = 92). Both formulations were 100% effective against larvae of the warble fly, Oedemagena tarandi, while oral treatment was less efficacious than s.c. injection against parasitic nematodes. Both formulations, but particularly the injectable ivermectin treatment, increased the weight gain of pregnant females compared to that of those not treated.

Administration, Oral

Spinal mobility and trunk muscle strength in 15-year-old schoolchildren with and without low-back pain.

From a population of 1,503 schoolchildren, 38 15-year-old children suffering from low-back pain and 38 asymptomatic controls were selected for testing of spinal mobility and trunk muscle strength. The asymptomatic controls were matched by age, sex, and school class. In the group with recurrent or continual low-back pain (17 boys and 21 girls), the boys were over 4 cm taller than those in the control group. In both sexes sagittal mobility was decreased in lumbar extension and straight leg raising, and increased in lumbar flexion. Endurance strength in the abdominal and back muscles was decreased compared to the control pupils, who reported no back pain at all in the questionnaire collected 1 year before the testing procedure. The pupils reporting sciatica (n = 7) at some time, in addition to recurrent low-back pain, had decreased lumbar flexion and side bending compared to those with recurrent low-back pain (n = 31) without sciatica. The results of the study indicated that in this growing-age population there was a subgroup with recurrent low-back pain having a different spinal mobility pattern as well as decreased trunk muscle strength.

Adolescent

Subject characteristics and low back pain in young athletes and nonathletes.

Factors associated with low back pain (LBP) were sought by means of a questionnaire and physical measurements in 138 adolescents. One-hundred athletes and 38 nonathletes, 138 subjects total (58 boys and 80 girls; age range 10.3-13.3 yr), were studied. The questionnaire included questions on physical activity and LBP. Quantitative measurements on anthropometry, flexibility (joint hypermobility and muscular tightness), and strength were performed. There was no significant difference in the occurrence of LBP between athletes and nonathletes. Among the athletes, the duration of training during the past 12 months (min.wk-1) was higher in subjects with the experience of LBP during the past 12 months (N = 23) compared with nonsymptomatic subjects (N = 76) (mean 493 +/- 308 min.wk-1 vs 354 +/- 160 min.wk-1; P less than 0.0001). Similar differences were also seen between subjects with positive lifetime histories of LBP and nonsymptomatic subjects. Various differences were seen in the measurements of anthropometry, flexibility, and strength between boys and girls as well as between athletes and nonathletes. In a multivariate analysis, the cumulative incidence of lifetime history of LBP was associated with tightness of hip flexor muscles only (P = 0.014). LBP during the past 12 months was associated only with the amount of training during the past 12 months (min.wk-1) (P = 0.0066). Our study suggests that high training duration predisposes young athletes to LBP. However, e.g., the flexibility measurements cannot be used to determine athletes at high risk.

Adolescent

Embryonation and infectivity of Ascaris suum eggs. A comparison of eggs collected from worm uteri with eggs isolated from pig faeces.

Ascaris suum eggs were collected from pig faeces or dissected from worms obtained from the same pigs. Eggs from the two sources were allowed to embryonate in 0.1 N H2SO4, in 1% buffered formalin or in tap water. The embryonation of the sulphuric acid and water cultures occurred at the same speed, while the formalin cultures developed slightly more slowly. By experimental inoculation of helminth-free pigs and subsequent counting of white spots in the livers and larvae in the lungs day 7 p.i., the infectivity of eggs dissected from worm uteri and embryonated in sulphuric acid (a normal laboratory procedure) was compared with that of eggs collected from faeces and embryonated in water (i.e. more naturally developed eggs). The results suggest that the two types of eggs were equally infective. For this reason the common practice of using Ascaris eggs dissected from worms for experimental infections might be acceptable.

Animals

Ivermectin as a bird anthelmintic--trials with naturally infected domestic fowl.

To evaluate the use of ivermectin as a bird anthelmintic, 29 White Leghorn hens naturally infected with Ascaridia spp., Heterakis spp. and Capillaria spp. were treated with 0.2, 2 or 6 mg/kg intramuscularly or 0.2 or 0.8 mg/kg orally. Faecal samples were collected before treatment and at autopsy, 2, 6, or 16 days after treatment, when the intestines were also examined for helminths. None of the treatments gave satisfactory anthelmintic results.

Animals

Fine structure of epithelial thymus cysts in dogs.

Epithelial thymus cysts in dogs were investigated by electron microscopy. Epithelial cells from one and the same cyst showed morphological differences. Regular columnar or cuboidal epithelial cells predominated. These had an elongated nucleus, poor in chromatin but with abundant cytoplasmic organelles, e.g. mitochondria, and a Golgi region with sacs and vacuoles. Other cells possesed a narrower, indented nucleus richer in chromatin, a cytoplasm with numerous tonofilaments and cell membranes showing interdigitations with other cell membranes. Some cysts displayed a pseudostratified epithelium. In these cells the same organelles were present as were seen in the cuboidal cells. Abundant cilia and microvilli were present in the lumenal cells. All these different morphological characteristics were considered to be different functional aspects of the same kind of thymus epithelial cell. The cells had a structure indicating a secretory-activity.

Age Factors

Testicular lesions of streptozotocin diabetic rats.

Diabetes was induced in adult male albino rats by a single intravenous injection of streptozotocin (75 mg/kg body weight). The diabetes was allowed to stabilize for at least 15 days, whereafter the testicular and seminal vesicle histology was studied at various time intervals. Reduction in testis weights and tubule diameters was significant after 2 weeks of diabetes. The changes in seminiferous tubules ranged from premature sloughing of epithelium to total cessation of spermatogenesis. The testicular histology of diabetic animals frequently greatly simulated the situation described following hypophysectomy. By subjective visual assessment the number of Leydig cells was found to be normal or reduced in all of the diabetic animals. Diabetes was also demonstrated to induce seminal vesicle atrophy, which did not show any correlation with the degree of testicular lesions. The possible etiology of testicular damage in diabetic animals is discussed.

Animals

Impaired 3H-testosterone uptake and metabolism in the accessory sex glands of diabetic castrated male rats.

The uptake and retention of 1,2-3H-testosterone in accessory sex glands, muscle and liver of streptozotocin diabetic castrated male rats, insulin-treated diabetic castrated rats and non-diabetic castrated control rats were studied at various time intervals after an intravenous injection. Diabetes reduced the retention of 3H-testosterone in the prostate, the preputial gland and the epididymis. Exogenous insulin slightly increased the retention of 3H-testosterone in these tissues of diabetic rats. No significant differences in the radioactivity in the rectus abdominis muscle, the coagulating glands and the seminal vesicles were found between the various experimental groups. Ventral prostate homogenates obtained from diabetic and control rats were incubated with 3H-testosterone in vitro. The steroids were extracted and thin-layer chromatographs were scanned for radioactivity. In prostatic homogenates taken from diabetic rats, testosterone transformation to dihydrotestosterone was reduced. The results indicate that the impaired function and androgen retention of the accessory sex glands of diabetic male rats is at least partly due to the reduced formation of dihydrotestosterone from testosterone.

Animals