Nordic consensus on treatment of undescended testes.

AIM: To reach consensus among specialists from the Nordic countries on the present state-of-the-art in treatment of undescended testicles. METHODS: A group of specialists in testicular physiology, paediatric surgery/urology, endocrinology, andrology, pathology and anaesthesiology from all the Nordic countries met for two days. Before the meeting, reviews of the literature had been prepared by the participants. RECOMMENDATIONS: The group came to the following unanimous conclusions: (1) In general, hormonal treatment is not recommended, considering the poor immediate results and the possible long term adverse effects on spermatogenesis. Thus, surgery is to be preferred. (2) Orchiopexy should be done between 6 and 12 months of age, or upon diagnosis, if that occurs later. (3) Orchiopexy before age one year should only be done at centres with both paediatric surgeons/urologists and paediatric anaesthesiologists. (4) If a testis is found to be undescended at any age after 6 months, the patient should be referred for surgery--to paediatric rather than general surgeons/urologists if the boy is less than one year old or if he has bilateral or non-palpable testes, or if he has got relapse of cryptorchidism.

Immunoglobulin class and subclass concentrations after treatment of childhood leukemia.

With greatly increased survival rates after childhood leukemia during the last 3 decades, the long-term effects of the treatment have become more evident. The disease and its treatment impair the immune system, but the duration of this impairment is unknown. The authors studied the serum concentrations of immunoglobulins and IgG subclasses in 20 Icelandic children cured of leukemia on average 8 years and 3 months after their treatment ended. Although no marked deviations were found in the concentrations of the main immunoglobulin classes IgA, IgM, IgG, and IgE, the IgG subclass levels were below reference values. The patients had on average 0.9 of age standardized reference values of IgG1, 0.5 of IgG2, 0.8 of IgG3, and 0.7 of IgG4. However, none had any autoimmune diseases or a markedly increased tendency for infections. The results indicate that although the immunoglobulin classes regain their normal values within a few years after cessation of treatment, recovery of the IgG subclasses, especially IgG2, is impaired.

Morphological, cytogenetic, and molecular evidence for introgressive hybridization in birch.

Extensive morphological variation of tetraploid birch (Betula pubescens) in Iceland is believed to be due to gene flow from diploid dwarf birch (B. nana) by means of introgressive hybridization. A combined morphological and cytogenetic approach was used to investigate this phenomenon in two geographically separated populations of natural birch woodland in Iceland. The results not only confirmed introgressive hybridization in birch, but also revealed bidirectional gene flow between the two species via triploid interspecific hybrids. The populations showed continuous morphological variation connecting the species, but karyotypically they consisted of only three types of plants: diploids, triploids, and tetraploids. No aneuploids were found. Some of the tetraploid plants had B. pubescens morphology as expected, but most of them had intermediate characters. Most of the diploid plants were B. nana, but some were intermediates and a few had B. pubescens morphology. The triploid plants were either intermediates or they resembled one of the two species. Similar introgressive variation was observed among the diploid and triploid progeny of open-pollinated B. nana in a garden. Birch samples including field plants and artificial hybrids were further examined using a molecular method based on genomic Southern hybridization. The experiments verified introgression at the DNA level.

Expression of the insulin like growth factor-binding protein 3 (IGFBP-3) gene is increased in human renal carcinomas.

After we had established that the IGFBP-3 gene is expressed in normal human kidney we examined renal adenocarcinoma tissue for alterations of the expression of this gene. For this purpose we prepared poly(A)+ RNA from normal kidney tissue and adjacent renal adenocarcinoma of 18 adult patients and compared the levels of IGFBP-3 mRNA by Northern analysis in both samples. The mean content by densitometry was markedly increased in the carcinoma tissues; in 17 of 18 patients the carcinoma contained significantly more IGFBP-3 mRNA than the normal kidney sample. The highest mRNA levels were found in patients with N2 and N3 lymph node extensions. Comparative Southern analysis of paired samples of four of these patients did not reveal amplification of the gene as the cause of these increased mRNA levels. In one patient, however, we identified a restriction fragment length polymorphism (RFLP) present in normal and malignant cellular DNA. This suggests a participation of the IGFBP-3 gene in the development of human renal cell cancer.

Effects of eccentric and concentric resistance training on skeletal muscle substrates, enzyme activities and capillary supply.

This study compared the skeletal muscle metabolic adaptations in response to combined eccentric and concentric or concentric resistance training regimens. Twenty-six physically active males were assigned to either the combined eccentric and concentric group (n = 10), the concentric group (n = 10) or the control group (n = 6). The combined eccentric and concentric and the concentric groups performed four to five sets of maximal, voluntary bilateral quadriceps muscle actions at 1.05 rad s-1 using a speed-controlled dynamometer three times per week for 12 weeks. The concentric group performed 12 concentric actions per set, whereas the combined eccentric and concentric group performed six coupled eccentric and concentric actions per set. Bilateral percutaneous muscle biopsies were obtained from m. vastus lateralis at rest pre- and post-training. Tissue samples were analysed for contents of adenosine triphosphate, creatine phosphate and creatine and for enzyme activities of citrate synthase, lactate dehydrogenase, myokinase, phosphofructokinase, hexokinase and Mg2(+)-ATPase using fluorometric techniques. Histochemical staining procedures were employed to determine capillary supply. The overall increase (P less than 0.05) in muscle strength was greater (P less than 0.05) for the combined eccentric and concentric group than for the concentric group. Enzyme or substrate contents and capillary supply were unaltered after either type of training. It is suggested that substantial increases in muscle strength may occur in response to resistance training without enhancing or compromising metabolic function of skeletal muscle.

Creatine phosphate in fiber types of skeletal muscle before and after exhaustive exercise.

Percutaneous muscle biopsies were obtained from the vastus lateralis of physically active men (n = 12) 1) at rest, 2) immediately after an exercise bout consisting of 30 maximal voluntary knee extensions of constant angular velocity (3.14 rad/s), and 3) 60 s after termination of exercise. Creatine phosphate (CP) content was analyzed in pools of freeze-dried fast-twitch (FT) and slow-twitch (ST) muscle fiber fragments, and ATP, CP, creatine, and lactate content were assayed in mixed pools of FT and ST fibers. CP content at rest was 82.7 +/- 11.2 and 73.1 +/- 9.5 (SD) mmol/kg dry wt in FT and ST fibers (P less than 0.05). After exercise the corresponding values were 25.4 +/- 19.8 and 29.7 +/- 14.4 mmol/kg dry wt. After 60 s of recovery CP increased (P less than 0.01) to 41.3 +/- 12.6 and 49.6 +/- 11.7 mmol/kg dry wt in FT and ST fibers, respectively. CP content after recovery, relative to initial level, was higher in ST compared with FT fibers (P less than 0.05). ATP content decreased (P less than 0.05) and lactate content rose to 67.4 +/- 28.3 mmol/kg dry wt (P less than 0.001) in response to exercise. It is concluded that basal CP content is higher in FT fibers than in ST fibers. CP content also appears to be higher in ST fibers after a 60-s recovery period after maximal short-term exercise. These data are consistent with the different metabolic profiles of FT and ST fibers.

Human skeletal muscle function and metabolism during intense exercise at high O2 and N2 pressures.

The maximal contractile force (peak torque) of the quadriceps femoris was studied during 60 repeated unilateral dynamic knee extensions in nine subjects under three different conditions, viz., during air breathing at normal (1 ATA) and raised (6 ATA) ambient pressures and during O2 breathing at 1.3 ATA. In six subjects the electromyographic (EMG) activity of the working muscle was recorded. Muscle biopsies were obtained from the vastus lateralis before, immediately after, and 1 min after exercise. Tissue specimens were subsequently assayed for various muscle metabolites. Peak torque, as an average of the 60 knee extensions, was higher (P less than 0.05) at 1.3 ATA than at 6 or 1 ATA. Peak torque of the exercising muscle declined more rapidly at 1 ATA than at 1.3 ATA, differing in the final 24 contractions by 14%. At 6 ATA peak torque of the initial 12 contractions was 6% lower (P less than 0.05) than at 1 ATA but equaled 1-ATA values in the latter third of the exercise bout. Although the EMG activity at 1 ATA increased relative to that at 6 ATA as exercise proceeded, the rate of force decline was greater at 1 ATA. Despite greater total work produced at 1.3 ATA than at 1 ATA, the metabolic response to exercise was not substantially altered at increased O2 pressure. However, the restitution rate of energy-rich phosphagens and the elimination of lactate during recovery were greater (P less than 0.05) at 1.3 ATA. These results suggest that hyperoxia may enhance the rate of energy release, whereas high N2 pressure and/or high hydrostatic pressure seem to interfere with neuromuscular activity.

Characterization of insulin-like growth factor II binding to human fibroblast monolayer cultures.

Two major somatomedin peptides have been isolated from human plasma, somatomedin-C/insulin-like growth factor I (SMC/IGF-I) and insulin-like growth factor II (IGF-II). Also, two types of SM/IGF receptors have been defined. Type I receptors have a higher affinity for SMC/IGF-I than IGF-II, and insulin binds to this receptor at high concentrations. Type II receptors have a higher affinity for IGF-II than SMC/IGF-I, and insulin does not bind to this receptor site. In this study, we characterized the binding of IGF-II to human monolayer fibroblast cultures, and the affinity and specificity of this binding. We also compared the binding of IGF-II to the binding of insulin and SMC/IGF-I to these cells. The receptors for IGF-II on normal human fibroblast monolayers fit the criteria for type II SM/IGF receptors, and there were more type II receptors on these cells than either insulin receptors or type I SM/IGF receptors. The type II receptors on human fibroblasts did not demonstrate autoregulation by homologous hormone, unlike the type I SM/IGF and insulin receptors. In addition, they were not changed by acute or chronic exposure to insulin. It is so far unclear what biological function IGF-II plays in vivo. This human fibroblast system will be a valuable experimental model for the study of IGF-II receptors and their relationship to the biological actions of IGF-II.

IGF-II binding on human lymphoid cells: demonstration of a common high affinity receptor for insulin like peptides.

We have studied the binding of 125I-GF-II to the IM-9 human lymphoid cell line, and to human placental membranes. All of IGF-II radioligand binding to IM-9 cells, and half of the binding to human placental membranes is to a previously unrecognized common (Type-III) high affinity receptor site for insulin-like peptides, in which IGF-I and IGF-II are equipotent and insulin only slightly less potent. This common receptor represents another mechanism by which insulin, and the somatomedins can exert biological action.