Avoidance of Cow's Milk-Based Formula for At-Risk Infants Does Not Reduce Development of Celiac Disease: A Randomized Controlled Trial

BACKGROUND & AIMS

Feeding during the first months of life might affect risk for celiac disease. Individuals with celiac disease or type 1 diabetes have been reported to have high titers of antibodies against cow's milk proteins. Avoidance of cow's milk-based formula for infants with genetic susceptibility for type 1 diabetes reduced the cumulative incidence of diabetes-associated autoantibodies. We performed a randomized controlled trial in the same population to study whether weaning to an extensively hydrolyzed formula reduced the risk of celiac disease autoimmunity or celiac disease.

METHODS

We performed a double-blind controlled trial of 230 infants with HLA-defined predisposition to type 1 diabetes and at least 1 family member with type 1 diabetes. The infants were randomly assigned to groups fed a casein hydrolysate formula (n = 113) or a conventional formula (control, n = 117) whenever breast milk was not available during the first 6-8 months of life. Serum samples were collected over a median time period of 10 years and analyzed for antibodies to tissue transglutaminase (anti-TG2A) using a radiobinding assay, to endomysium using an immunofluorescence assay, and antibodies to a deamidated gliadine peptide using an immunofluorometry assay. Duodenal biopsies were collected if levels of anti-TG2A exceeded 20 relative units. Cow's milk antibodies were measured during the first 2 years of life.

RESULTS

Of the 189 participants analyzed for anti-TG2A, 25 (13.2%) tested positive. Of the 230 study participants observed, 10 (4.3%) were diagnosed with celiac disease. We did not find any significant differences at the cumulative incidence of anti-TG2A positivity (hazard ratio, 1.14; 95% confidence interval, 0.51-2.54) or celiac disease (hazard ratio, 4.13; 95% confidence interval, 0.81-21.02) between the casein hydrolysate and cow's milk groups. Children who developed celiac disease had increased titers of cow's milk antibodies before the appearance of anti-TG2A or celiac disease.

CONCLUSIONS

In a randomized controlled trial of 230 infants with genetic risk factors for celiac disease, we did not find evidence that weaning to a diet of extensively hydrolyzed formula compared with cow's milk-based formula would decrease the risk for celiac disease later in life. Increased titers of cow's milk antibody before anti-TG2A and celiac disease indicates that subjects with celiac disease might have increased intestinal permeability in early life. ClinicalTrials.gov Number: NCT00570102.

Probe based manipulation and assembly of nanowires into organized mesostructures

A convenient approach to patterning inorganic and organic nanowires using a novel probe manipulator is presented. The system utilizes an electrochemically etched tungsten wire probe mounted onto a 3D actuator that is directed by a 3D controller. When it is engaged by the user, the movement of the probe and the forces experienced by the tip are simultaneously reported in real time. Platinum nanowires are manipulated into organized mesostructures on silicon chip substrates. In particular, individual nanowires are systematically removed from aggregates, transferred to a chosen location, and manipulated into complex structures in which selected wires occupy specific positions with defined orientations. Rapid prototyping of complex mesostructures, by pushing, rotating and bending conjugated polymer, i.e., polyfluorene, nanowires into various configurations, is also achieved. By exploiting the strong internal axial alignment of polymer chains within the polyfluorene nanowires, mesostructures tailored to exhibit distinctly anisotropic optical properties, such as birefringence and photoluminescence dichroism, are successfully assembled on fused silica substrates.

Lumbar bone mineral density in normal subjects aged 3-6 years: a prospective study

Longitudinal studies on bone mineral density (BMD) accrual in young children are scarce. The purpose of the present study was to evaluate prospectively the development of spinal BMD in healthy Finnish children aged 3-6 y by dual-energy x-ray absorptiometry (DXA). Lumbar spine (L2-L4) areal BMD (g/cm2) was measured by DXA (Lunar DPX) in 20 children (10M, 10F) aged 3.3-6.9 y (median 4.8 y) at baseline and after a median follow-up of 1.0y (range 0.8-1.1 y). Apparent volumetric BMD (BMDvol, g/cm3) was calculated to minimize the effect of bone size on BMD in growing spine. At baseline, lumbar areal and volumetric BMDs (mean +/- SD) for males were 0.623+/-0.087 g/cm2 and 0.270+/-0.034 g/cm3, respectively, and for females 0.620+/-0.082 g/cm2 and 0.254+/-0.035 g/cm3, respectively. During the median follow-up of 1 y, lumbar areal and volumetric BMDs (mean +/- SD) increased in males by 4.7+/-2.7% (p < 0.01) and 3.5+/-3.5% (p <0.05), respectively, and in females by 7.2+/-5.3% (p <0.01) and 3.1+/-3.1% (p <0.05), respectively. No statistically significant difference in the BMD values was observed between the sexes.

CONCLUSION

A significant increase in both areal and apparent volumetric BMD was observed in children aged 3-6 y during a follow-up of I y. The increase in volumetric BMD indicated that there was a real accrual of BMD in growing spine measured by DXA. The present study provides prospective data on BMD accrual in young children for the evaluation of bone mass development in early childhood.

A theoretical study of the77Se NMR and vibrational spectroscopic properties of SenS8–nring molecules

The structures and spectroscopic properties of SenS8–nring molecules have been studied by the use of ab initio molecular orbital techniques and density functional techniques involving Stuttgart relativistic large core effective core potential approximation with double zeta basis sets for valence orbitals augmented by two polarization functions for both sulfur and selenium. Full geometry optimizations have been carried out for all 30 isomers at the Hartree-Fock level of theory. The optimized geometries and the calculated fundamental vibrations and Raman intensities of the SenS8–nmolecules agree closely with experimental information where available. The nuclear magnetic shielding tensor calculations have been carried out by the Gauge-independent atomic orbital method at the DFT level using Becke's three-parameter hybrid functional with Perdew/Wang 91 correlation. The isotropic shielding tensors correlate well with the observed chemical shift data. The calculated chemical shifts provide a definite assignment of the observed77Se NMR spectroscopic data and can be used in the prediction of the chemical shifts of unknown SenS8–nring molecules.Key words: selenium sulfides, ab initio, DFT, effective core potentials, geometry optimization, energetics, fundamental vibrations,77Se chemical shifts.

Acute insulin response tests for the differential diagnosis of congenital hyperinsulinism

Mutations in genes encoding the two subunits of the beta-cell ATP-sensitive potassium channel (K(ATP)) channel (SUR1 and Kir6.2) are the major cause of congenital hyperinsulinism (CHI). In this study, the K(ATP) channel genes were screened in a population-based study that included all verified Finnish CHI patients (n = 43) in a 27-yr period. Seven different mutations were identified, which accounted for 60% of all cases. The functional consequences of the major missense mutations were studied in vivo by determining acute (1-3 min) plasma insulin and C-peptide responses to calcium (n = 18), glucose (n = 12), and tolbutamide (n = 11) in those CHI patients who were able to take part in these studies. C-peptide and insulin responses to calcium were significantly higher in the patients with SUR1-E1506K mutation, compared with patients without K(ATP) channel mutations. The patients with SUR1-V187D mutation showed a reduced response to tolbutamide but unexpectedly did not show any response to calcium stimulation. A compound heterozygous patient with Kir6.2-(-54)/K67N mutations responded to calcium but also to tolbutamide. In conclusion, our results show that a positive response in the calcium test is indicative of a K(ATP) channel mutation, but all mutations cannot be identified with this method. The insulin response to tolbutamide in patients with SUR1 mutations is impaired to different extents, depending on the genotype. The combination of calcium and tolbutamide tests is a useful tool for the detection of CHI patients with K(ATP) channel dysfunction. Our results, however, also demonstrate the complexity of these responses and the difficulties in their interpretation.

Lack of cytosolic and transmembrane domains of type XIII collagen results in progressive myopathy

Type XIII collagen is a type II transmembrane protein found at many sites of cell adhesion in tissues. Homologous recombination was used to generate a transgenic mouse line (Col13a1(N/N)) that expresses N-terminally altered type XIII collagen molecules lacking the short cytosolic and transmembrane domains but retaining the large collagenous ectodomain. The mutant molecules were correctly transported to focal adhesions in cultured fibroblasts derived from the Col13a1(N/N) mice, but the cells showed decreased adhesion when plated on type IV collagen. These mice were viable and fertile, and in immunofluorescence stainings the mutant protein was located in adhesive tissue structures in the same manner as normal alpha1(XIII) chains. In immunoelectron microscopy of wild-type mice type XIII collagen was detected at the plasma membrane of skeletal muscle cells whereas in the mutant mice the protein was located in the adjacent extracellular matrix. Affected skeletal muscles showed abnormal myofibers with a fuzzy plasma membrane-basement membrane interphase along the muscle fiber and at the myotendinous junctions, disorganized myofilaments, and streaming of z-disks. The findings were progressive and the phenotype was aggravated by exercise. Thus type XIII collagen seems to participate in the linkage between muscle fiber and basement membrane, a function impaired by lack of the cytosolic and transmembrane domains.

Post-prandial insulin lispro vs. human regular insulin in prepubertal children with Type 1 diabetes mellitus

AIMS

To study whether post-prandial insulin lispro (PL) could be used as a part of insulin therapy instead of premeal human regular insulin (HR) in prepubertal children with Type 1 diabetes mellitus (Type 1 DM).

PATIENTS AND METHODS

In this open, randomized cross-over study patients used either PL or HR at breakfast and at dinner. After a 1-month screening period, patients were randomized to treatment with PL or HR for 3 months and then they crossed over to the other insulin for an additional 3 months. The patients were 24 prepubertal children with Type 1 DM (median age 6.2 years, duration of diabetes 37 months). Home monitoring of 1-day glucose profiles at meals (premeal, 1 h and 2 h after breakfast and after dinner) and HbA1c were measured before randomization, before cross-over, and at the last visit. Data on hypoglycaemic episodes were collected at each of the seven visits. The variables were compared between the two treatments.

RESULTS

Of the patients 22/24 completed the study. There were no major differences in the glucose excursions between PL and HR after breakfast (mean +/- SD: 1-h PL 3.7 +/- 4.7 vs. HR 2.9 +/- 3.9 mmol/l, P = 0.3; 2-h -0.9 +/- 5.4 vs. 0.3 +/- 4.5 mmol/l, P = 0.2, respectively) or after dinner (1-h PL -2.5 +/- 4.8 vs. HR -0.4 +/- 3.7 mmol/l, P = 0.07, 2-h -4.1 +/- 5.2 vs. -0.7 +/- 5.0 mmol/l, P = 0.05, respectively). Mean change of HbA1c was similar in both treatment groups (PL 0.2 +/- 0.8% vs. HR -0.4 +/- 0.7%, P = 0.1). The frequency of hypoglycaemic episodes was 4.9 per patient per month during treatment with PL, and 4.4 during HR (P = 0.3).

CONCLUSION

Treatment with post-prandial lispro as a meal insulin is as effective and safe as traditional treatment with regular insulin in young children.

An open-label acceptability study of Norditropin SimpleXx--a new liquid growth hormone formulation

A new liquid formulation of hGH (Norditropin SimpleXx) has been developed to avoid the need for reconstitution before administration. In addition, the liquid GH formulation has been combined with an advanced pen delivery system, either with or without a needle auto-insertion mechanism. This study was designed to assess the acceptability of the new system compared with the patient's previous system. A total of 103 children with GH deficiency received a daily injection of Norditropin liquid GH for 12 weeks with a choice of a pen/auto-insertion system. Acceptability was determined by nurse-supervised questionnaires administered to the patients and parents. Following treatment, 94% of patients preferred the Norditropin liquid GH system. This preference was irrespective of the previous system in use, patient age or length of GH therapy. More patients found it the less painful system (50% vs 13%), 92% of patients found it more convenient, and the formulation was well tolerated. In conclusion, Norditropin liquid GH was very well accepted and preferred by the majority of patients. It avoided reconstitution which had been a major cause of dissatisfaction with the patients' previous systems, and resulted in greater convenience and reduced levels of pain associated with injection.

Acute exercise induced changes in rat skeletal muscle mRNAs and proteins regulating type IV collagen content

This experiment tested the hypothesis that running-induced damage to rat skeletal muscle causes changes in synthesis and degradation of basement membrane type IV collagen and to proteins regulating its degradation. Samples from soleus muscle and red and white parts of quadriceps femoris muscle (MQF) were collected 6 h or 1, 2, 4, or 7 days after downhill running. Increased muscle beta-glucuronidase activity indicated greater muscle damage in the red part of MQF than in the white part of MQF or soleus. In the red part of MQF, type IV collagen expression was upregulated at the pretranslational level and the protein concentration decreased, whereas matrix metalloproteinase-2 (MMP-2), a protein that degrades type IV collagen, and tissue inhibitor of metalloproteinase-2 (TIMP-2), a protein that inhibits degradation, were increased in parallel both at mRNA and protein levels. Type IV collagen mRNA level increased in the white part of MQF and soleus muscle. The protein concentration increased in the white part of MQF and was unchanged in soleus muscle. MMP-2 and TIMP-2 changed only slightly in the white part of MQF and soleus muscle. The changes seem to depend on the severity of myofiber injury and thus probably reflect reorganization of basement membrane compounds.

Lack of type XV collagen causes a skeletal myopathy and cardiovascular defects in mice

Type XV collagen occurs widely in the basement membrane zones of tissues, but its function is unknown. To understand the biological role of this protein, a null mutation in the Col15a1 gene was introduced into the germ line of mice. Despite the complete lack of type XV collagen, the mutant mice developed and reproduced normally, and they were indistinguishable from their wild-type littermates. However, Col15a1-deficient mice showed progressive histological changes characteristic for muscular diseases after 3 months of age, and they were more vulnerable than controls to exercise-induced muscle injury. Despite the antiangiogenic role of type XV collagen-derived endostatin, the development of the vasculature appeared normal in the null mice. Nevertheless, ultrastructural analyses revealed collapsed capillaries and endothelial cell degeneration in the heart and skeletal muscle. Furthermore, perfused hearts showed a diminished inotropic response, and exercise resulted in cardiac injury, changes that mimic early or mild heart disease. Thus, type XV collagen appears to function as a structural component needed to stabilize skeletal muscle cells and microvessels.

Dominantly inherited hyperinsulinism caused by a mutation in the sulfonylurea receptor type 1

ATP-sensitive potassium channels play a major role in linking metabolic signals to the exocytosis of insulin in the pancreatic beta cell. These channels consist of two types of protein subunit: the sulfonylurea receptor SUR1 and the inward rectifying potassium channel Kir6.2. Mutations in the genes encoding these proteins are the most common cause of congenital hyperinsulinism (CHI). Since 1973, we have followed up 38 pediatric CHI patients in Finland. We reported previously that a loss-of-function mutation in SUR1 (V187D) is responsible for CHI of the most severe cases. We have now identified a missense mutation, E1506K, within the second nucleotide binding fold of SUR1, found heterozygous in seven related patients with CHI and in their mothers. All patients have a mild form of CHI that usually can be managed by long-term diazoxide treatment. This clinical finding is in agreement with the results of heterologous coexpression studies of recombinant Kir6.2 and SUR1 carrying the E1506K mutation. Mutant K(ATP) channels were insensitive to metabolic inhibition, but a partial response to diazoxide was retained. Five of the six mothers, two of whom suffered from hypoglycemia in infancy, have developed gestational or permanent diabetes. Linkage and haplotype analysis supported a dominant pattern of inheritance in a large pedigree. In conclusion, we describe the first dominantly inherited SUR1 mutation that causes CHI in early life and predisposes to later insulin deficiency.

Design of the SGML-based electronic patient record system with the use of object-oriented analysis methods

Since a patient record is typically a document updated by many users, required to be represented in many different layouts, and transferred from place to place, it is a good candidate to be represented structured and coded using the SGML document standard. The use of the SGML requires that the structure of the document is defined in advance by a Document Type Definition (DTD) and the document follows it. This paper represents a method which derives an SGML DTD by starting from the description of the usage of the patient record in medical care and nursing.

Controlled lengthening or shortening contraction-induced damage is followed by fiber hypertrophy in rat skeletal muscle

To study the hypothesis that more severe damage, caused by controlled lengthening (L) contractions, results in greater myofiber hypertrophy compared to increase in fiber size followed shortening (S) contractions, tibialis anterior muscles of anesthesized male Wistar rats were subjected to 240 either L or S contractions. The highest increase in muscle beta-glucuronidase activity, an indicator of muscle damage, was observed in L (7.1-fold) 4 days and in S (2.6-fold) 8 days postexercise. Dystrophin- and desmin-negative as well as fibronectin-positive fibers (signs of the early phase of damage) were observed immediately after exercise in the L group. At 4 days, massive myofiber injury was visible, and internally localized nuclei were present at 15-80 days after exercise in the L group. The shift towards more glycolytic fiber types (p<0.05 in L and S) and an increased mean cross-sectional area of type IIX/B fibers (p < 0.001 in L and S) at 80 days were observed in both groups. The observed minor damage with unchanged myofiber structures following S induced, however, an increase in myofiber cross-sectional area of nearly the same magnitude as that following L, which was more damaging. The results do not support the hypothesis that fiber hypertrophy depends on the extent of the myofiber damage upon the exercised muscles.

Signaling between the pituitary gland and the testes: inverse relationship between serum FSH and inhibin B concentrations in boys in early puberty

OBJECTIVES

To study the relationship between serum inhibin B and sex steroid concentrations and pituitary FSH responsiveness to GnRH in boys in early puberty, and to examine serum inhibin B levels in prepubertal boys with different timing of the onset of gonadotropin deficiency (GD).

DESIGN

Twenty-five boys with constitutional delay of puberty (CDP; 20 in Tanner stage G2 and 5 in G3; age range, 13. 5-16.8 years) and eight prepubertal boys (G1P1) with GD (age range, 10.0-13.2 years) were clinically examined, and serum inhibin B, testosterone and estradiol concentrations were measured from sera obtained immediately before the administration of GnRH (Relefact; 3.5 microgram/kg, maximum 100 microgram i.v.). Thereafter, FSH levels were measured at 30min intervals up to 90min.

RESULTS

In the boys with CDP, basal inhibin B and FSH levels did not correlate. However, inhibin B and GnRH-stimulated FSH concentrations (r(S)= -0.43 to -0.45, n=25, P<0.05) and the difference between basal and peak serum FSH levels were inversely related (r(S)= -0.63, n=25, P<0.005). This relationship remained significant in boys at stage G2 (r(S)= -0.66, n=20, P<0.005). Basal testosterone concentrations and GnRH-induced FSH levels did not correlate. Estradiol levels were too low (64% of the boys had estradiol levels below the assay sensitivity) to allow correlation analysis. The boys with GD had low inhibin B concentrations (range, <15.6-53pg/ml); the lowest levels were observed in boys with presumably congenital onset of the disease. Serum inhibin B levels and testis volumes correlated positively (r(S)=0.70, n=8, P=0.07).

CONCLUSIONS

These results suggest that, in boys, the reciprocal regulation between inhibin B and FSH is in operation before mid-puberty. Moreover, autonomous inhibin B secretion by the prepubertal human testis is likely to reflect the number of Sertoli cells.

Impaired development of bone mineral density during chemotherapy: a prospective analysis of 46 children newly diagnosed with cancer

Osteopenia and osteoporosis are becoming increasingly recognized in children with cancer, though reasons for these changes are poorly understood. The purpose of the present study was to evaluate longitudinal changes in bone mineral density (BMD) and bone turnover in newly diagnosed children with a malignancy. Lumbar spine (L2-L4) and femoral neck bone mineral density (BMDareal, g/cm2) was measured by dual-energy X-ray absorptiometry in 46 children (age 2.9-16.0, median 8.0 years; 15 leukemias, 12 lymphomas, 19 solid tumors) at diagnosis, and after 6 months from the baseline. The apparent volumetric bone mineral density (BMDvol) was calculated to minimize the effect of bone size on BMD. Serum levels of osteocalcin (OC), type I collagen carboxy-terminal propeptide (PICP), and type I collagen carboxy-terminal telopeptide (ICTP) were analyzed at diagnosis, and during a 6-month follow-up. A significant decrease in lumbar BMDvol (-2.1%, p < 0.05), and in femoral BMDareal (-9.9%, p = 0.0001) and BMDvol (-8.5%, p = 0.0001) was observed after 6 months when compared with baseline measurements. The markers of bone formation (PICP, OC) were significantly decreased, and the marker of bone resorption (ICTP) was significantly increased at diagnosis as compared with normal values. By the end the follow-up, the levels of PICP and OC were normalized, whereas the level of ICTP continued to increase indicating that there was a negative balance in bone turnover. A deficient accumulation of bone mass might predispose children with a malignancy to impaired development of peak bone mass. A controlled study determining the benefits of an early intervention on bone turnover should be considered in these patients.

Clinical, autoimmune, and genetic characteristics of very young children with type 1 diabetes. Childhood Diabetes in Finland (DiMe) Study Group

OBJECTIVE

To study the characteristics of type 1 diabetes in very young children.

RESEARCH DESIGN AND METHODS

Clinical outcome, islet cell antibodies (ICA), insulin autoantibodies (IAA), antibodies against GAD (GADA), IA-2 antibodies (IA-2A), and HLA-DQB1-defined genetic risk were analyzed in 35 children diagnosed with type 1 diabetes before 2 years of age and compared with those in 146 children who were diagnosed between 2.0 and 4.9 years of age and with those in 620 children diagnosed between 5.0 and 14.9 years of age.

RESULTS

The youngest age-group had severer metabolic decompensation at clinical onset, and their serum C-peptide levels, compared with those of older children, were lower at the time of diagnosis and during the first 2 years after the diagnosis. The levels of ICA and IAA were highest in children < 2 years of age, but there were no differences in GADA levels among the three age-groups. The youngest age-group had the lowest IA-2A levels. The HLA DQB1*02/*0302 genotype associated with strong genetic susceptibility was more frequent in children diagnosed < 5 years of age, whereas the proportion of children carrying a genotype, which includes protective alleles, was higher among those diagnosed at > or = 5 years of age.

CONCLUSIONS

The clinical presentation of type 1 diabetes at a very young age is associated with severe metabolic decompensation, poorly preserved residual beta-cell function, strong humoral autoimmunity against islet cells and insulin, and strong HLA-defined disease susceptibility.

Disturbance in bone turnover in children with a malignancy at completion of chemotherapy

BACKGROUND

Osteoporosis and pathological fractures have been observed in children with a malignancy. The mechanisms of osteopenia in childhood malignancies have not been well established. The purpose of the present study was to evaluate changes in bone turnover and in bone hormonal metabolism in children with a malignancy at completion of their chemotherapy.

PROCEDURE

Serum levels of human intact osteocalcin, type I collagen carboxyterminal propeptide (PICP), type I collagen carboxyterminal telopeptide (ICTP), 25-hydroxyvitamin D [25-(OH)-D], 1,25-dihydroxyvitamin D [1, 25-(OH)(2)-D], intact parathyroid hormone, insulin-like growth factor I (IGF-I), IGF binding protein 3 (IGFBP-3), alkaline phosphatase, calcium, and phosphate were analyzed in 22 children with acute lymphoblastic leukemia and in 26 children with other malignancies. Results were expressed as Z-scores [mean (95% confidence intervals)] relative to healthy Caucasian-children.

RESULTS

The marker of collagen degradation (ICTP) was significantly increased [1.43 (1.10-1.76), P < 0.0001] compared to reference values, whereas the markers of bone formation (PICP, osteocalcin) were not changed [0.07 (-0.55 to 0.49), 0.35 (-0.05 to 0.74), respectively, NS]. Serum 25-(OH)-D, 1,25-(OH)(2)-D, and calcium were significantly reduced [-0.65 (-0.87 to -0.42), -0.68 (-0.92 to -0. 42), -1.42 (-1.80 to -1.04), P < 0.0001, respectively].

CONCLUSIONS

Disturbance in bone turnover with low serum 25-(OH)-D, 1, 25-(OH)(2)-D, and calcium was observed in children with a malignancy at completion of their chemotherapy. A controlled study determining the possible benefits of vitamin D and calcium supplementation on bone turnover could be considered in these patients.

Alterations in bone turnover and impaired development of bone mineral density in newly diagnosed children with cancer: a 1-year prospective study

In the present study, longitudinal changes in bone mineral density, bone turnover, and bone hormonal metabolism were evaluated in newly diagnosed children with cancer. Lumbar spine (L2-L4) and femoral neck bone mineral densities (grams per cm2) were measured by dual energy x-ray absorptiometry in 28 children (age, 2.9-16.0 yr; median, 8.0 yr; 10 acute lymphoblastic leukemias, 18 solid tumors) at diagnosis and after a 1-yr follow-up. Apparent volumetric density (grams per cm3) was calculated to minimize the effect of bone size on BMD. Serum levels of osteocalcin (OC), type I collagen carboxyl-terminal propeptide (PICP), and type I collagen carboxyl-terminal telopeptide were measured serially during the study. Serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, insulin-like growth factor I (IGF-I), and IGF-binding protein-3 were analyzed at diagnosis and at 1-yr follow-up. A significant decrease in femoral bone mineral density and apparent volumetric density was observed during the year after diagnosis [(mean (SD), -10.1% (8.8%) and -11.3% (8.1%) respectively; P < 0.01], whereas age- and sex-matched controls showed annual increments of +5.4% (7.7%; P < 0.01) and +0.7% (5.7%; P = NS) respectively. The markers of bone formation (PICP and OC) were significantly decreased at diagnosis. By the end of the follow-up, PICP and OC were normalized, whereas the marker of bone resorption (type I collagen carboxyl-terminal telopeptide) was significantly increased. Reduced levels of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and IGF-binding protein-3 were observed during the study. To conclude, increased bone resorption and impaired development of femoral bone density were observed in children with cancer during chemotherapy. Deficient accumulation of bone mass may lead to impaired development of peak bone mass and predispose children with cancer to increased risk of osteoporosis and diminished skeletal resistance to fractures later in life.

Increased mRNAs for procollagens and key regulating enzymes in rat skeletal muscle following downhill running

The purpose of the study was to investigate pre-translational regulation of collagen expression after a single bout of exercise. We analysed steady-state messenger ribonucleic acid (mRNA) levels for collagen types I, III and IV, alpha- and beta-subunits of prolyl 4-hydroxylase and lysyl oxidase (enzymes modifying procollagen chains), and enzyme activity of prolyl 4-hydroxylase from rat soleus muscle (MS) and the red parts of quadriceps femoris muscle (MQF) after 12 h and after 1, 2, 4, 7 and 14 days of downhill (-13.5 degrees ) treadmill running at a speed of 17 m.min-1 for 130 min. Histological and biochemical assays revealed exercise-induced muscle damage in MQF but not MS. Steady-state mRNA levels for the alpha- and beta-subunits of prolyl 4-hydroxylase in MQF, lysyl oxidase in MS and MQF were increased 12 h after running, whereas prolyl 4-hydroxylase activity did not increase until 2 days after exercise. The mRNA levels for the fibrillar collagens (I and III) and basement membrane type IV collagen significantly increased 1 day and 12 h after exertion, respectively. Peak mRNA levels were observed 2-4 days after running, the increases being more pronounced in MQF than in MS. No significant changes were observed in types I or III collagen at the protein level. Strenuous downhill running thus causes an increase in gene expression for collagen types I and III and their post-translational modifying enzymes in skeletal muscle in a co-ordinated manner. These changes, together with the increased gene expression of type IV collagen, may represent the regenerative response of muscle extracellular matrix to exercise-induced injury and an adaptive response to running exertion.

Reduced bone density at completion of chemotherapy for a malignancy

OBJECTIVES

Osteoporosis and pathological fractures occur occasionally in children with malignancies. This study was performed to determine the degree of osteopenia in children with a malignancy at completion of chemotherapy.

METHODS

Lumbar spine (L2-L4) bone mineral density (BMD; g/cm2) and femoral neck BMD were measured by dual energy x ray absorptiometry in 22 children with acute lymphoblastic leukaemia (ALL), and in 26 children with other malignancies. Apparent volumetric density was calculated to minimise the effect of bone size on BMD. Results were compared with those of 113 healthy controls and expressed as age and sex standardised mean Z scores.

RESULTS

Patients with ALL had significantly reduced lumbar volumetric (-0.77) and femoral areal and volumetric BMDs (-1.02 and -0.98, respectively). In patients with other malignancies, femoral areal and apparent volumetric BMDs were significantly decreased (-0.70 and -0.78, respectively).

CONCLUSIONS

The results demonstrate that children with a malignancy are at risk of developing osteopenia. A follow up of BMD after the completion of chemotherapy should facilitate the identification of patients who might be left with impaired development of peak bone mass, and who require specific interventions to prevent any further decrease in their skeletal mass and to preserve their BMD.

A point mutation inactivating the sulfonylurea receptor causes the severe form of persistent hyperinsulinemic hypoglycemia of infancy in Finland

Mutations in genes encoding the ATP-regulated potassium (K(ATP)) channels of the pancreatic beta-cell (SUR1 and Kir6.2) are the major known cause of persistent hyperinsulinemic hypoglycemia of infancy (PHHI). We collected all cases of PHHI diagnosed in Finland between 1983 and 1997 (n = 24). The overall incidence was 1:40,400, but in one area of Central Finland it was as high as 1:3,200. Haplotype analysis using polymorphic markers spanning the SUR1/Kir6.2 gene cluster confirmed linkage to the 11p region. Sequence analysis revealed a novel point mutation in exon 4 of SUR1, predicting a valine to aspartic acid change at amino acid 187 (V187D). Of the total cases, 15 affected individuals harbored this mutation in heterozygous or homozygous form, and all of these had severe hyperinsulinemia that responded poorly to medical treatment and required subtotal pancreatectomy. No K(ATP) channel activity was observed in beta-cells isolated from a homozygous patient or after coexpression of recombinant Kir6.2 and SUR1 carrying the V187D mutation. Thus, the mutation produces a nonfunctional channel and, thereby, continuous insulin secretion. This unique SUR1 mutation explains the majority of PHHI cases in Finland and is strongly associated with a severe form of the disease. These findings provide diagnostic and prognostic utility for suspected PHHI patients.

Gender differences in skeletal muscle fibre damage after eccentrically biased downhill running in rats

Specific antibodies against structural proteins of muscle fibres (actin, desmin, dystrophin) and extracellular matrix (fibronectin) were used to study the effect of eccentrically biased downhill running exercise (13,5 degrees, 17 m min(-1), 130 min) on the magnitude and properties of myofibre injury in the quadriceps femoris muscle of male and female rats. Muscle beta-glucuronidase activity, a quantitative indicator of muscle damage, showed clearly smaller increase in female than in male rats during the 4-day period following exercise. A similar course of histopathological changes was observed in both sexes, although females showed slower and less marked changes than males. In males, discontinuous or even lost submembrane protein dystrophin staining was observed in some swollen fibres immediately after exercise, before the loss of desmin and staining of disorganized actin, i.e. before the disruption of the cytoskeletal system and the contractile apparatus. The observation that no dramatic changes in the microarchitecture of the muscle fibres were detected immediately or even 6 h after the exercise in females compared with males may indicate that the sarcolemma of the females might be strengthened against membrane damage by a still unknown stabilizing compound.

Submaximal exercise in the cold: does cooling potentiate the development of muscle injuries in the rat?

To test the effect of low ambient temperature on muscular strain and possible development of muscle injuries, male Sprague-Dawley rats (n = 35) were exercised at a speed of 15 m min-1 on a treadmill at a 6 degrees inclination for 1.5 h in a warm (22 degrees C) or a cold (-10 degrees C) environment. Blood and tissue samples were collected 0 and 48 h postexercise. Blood glucose, lactate, pyruvate, cortisol, epinephrine (E) and norepinephrine (NE) were determined to investigate the effect on energy metabolism. To estimate the degree of physical strain, possible muscle injury and regenerative processes of muscles in response to exercise in the cold, serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle beta-glucuronidase and prolyl-4-hydroxylase (PH) activities were measured. In addition, histology of the hindlimb muscles m. soleus and m. tibialis anterior was examined. In general, the circulating level of metabolic substrates during exercise were unaffected by the exercise and independent of ambient temperature. Plasma cortisol increased significantly during exercise (P < 0.01), but was unaffected by the thermal strain. Of the myocellular enzymes, serum CK increased by 100% (P < 0.01) and LDH by 93% (P < 0.05) during exercise in the cold compared with exercise in warm, indicating a higher physical strain. However, exercise in the cold did not result in muscle injuries as judged by the unaltered muscular beta-glucuronidase, PH levels and muscle morphology. It is concluded that the exercise type and intensity used caused stress that was independent of the ambient temperature. In addition, the rats were able to maintain unaltered circulating levels of energy substrates also in the cold. Finally, exercise in the cold increased muscular strain but did not result in muscle injuries.

The disruption of myofibre structures in rat skeletal muscle after forced lengthening contractions

Specific antibodies against structural proteins (actin, desmin, dystrophin, fibronectin) of muscle fibres were used to study the effect of forced lengthening contractions on muscle microarchitecture. Tibialis anterior (TA) muscle of male Wistar rats were subjected to 240 forced lengthening contractions. At consecutive time points (0, and 6 h, 2, 4, and 7 days) after stimulation, the TA muscle was excised for biochemical and histological assays. Beta-Glucuronidase activity, a quantitative indicator of muscle damage, showed increased values 2-7 days after the lengthening, peaking on day 4 (11.7-fold increase). A typical course of histopathological changes (myofibre swelling, necrosis and regeneration) was observed. In immunohistochemistry, the earliest abnormality observed was discontinuous dystrophin staining in some swollen fibres immediately after commencement of exercise, while at the same time no alterations occurred in the staining of the other antibodies studied. Six hours later, all the swollen fibres were uniformly desmin as well as dystrophin negative. The great majority, but not all, of the swollen fibres showed disorganized actin staining and intramyocellular localization of fibronectin. The early phase disruption of myofibre structures as measured in this study provides evidence of their central role following damage in skeletal muscle. These results suggest that the sequence of structural changes in the route to muscle fibre necrosis in injury induced by forced lengthening contraction originates in the disruption of the plasma membrane and the intermediate filament, which leads to disturbances in the myofibrillar system.

Prepubertal girls with insulin-dependent diabetes mellitus have higher exogenous insulin requirement than boys. Childhood Diabetes in Finland Study Group

In a population based study, the prescribed insulin dose of 348 prepubertal children with insulin-dependent diabetes mellitus (IDDM) was analysed 2 years after the diagnosis of diabetes. Girls had an insulin dose 13.6% higher than that in boys. When children younger than 5 years of age at diagnosis were analysed separately, the difference in insulin dose between boys and girls remained. The increased insulin dose in girls was not explained by possible differences in endogenous insulin secretion, body mass index, metabolic control or the number of daily insulin injections. Our observations indicate that prepubertal girls with IDDM have a poorer insulin sensitivity than boys.

Reduced bone mineral density in long-term survivors of childhood acute lymphoblastic leukemia

PURPOSE

Osteoporosis and pathologic fractures are occasionally found in patients with childhood acute lymphoblastic leukemia (ALL). This study was performed to determine the degree of possible osteopenia in long-term survivors of childhood ALL.

PATIENTS AND METHODS

Lumbar spine (L2-L4) and femoral neck bone mineral densities (BMDs) (g/cm2) were measured in 29 survivors (aged 12 to 30 years, median 17) of childhood ALL 2 to 20 (median 8) years after discontinuation of chemotherapy. These results were compared with those from 273 healthy controls and expressed as a percentage of the age- and sex-matched control values (mean +/- standard deviation).

RESULTS

Lumbar and femoral BMDs were significantly reduced in survivors of childhood ALL. Particularly, male gender (lumbar: 91.7 +/- 10.4%, p = 0.008; femoral: 91.9 +/- 11.3%, p = 0.005) and a history of cranial irradiation (lumbar: 93.0 +/- 8.9%, p = 0.005; femoral: 94.4 +/- 13.3%, p = 0.03) were associated with low lumbar and femoral BMDs.

CONCLUSIONS

The detected deficit in bone density in survivors of childhood ALL may predispose these patients to osteoporotic fractures later in adulthood. A follow-up of BMD in survivors of childhood ALL should facilitate the identification of patients who would require specific therapeutic interventions to prevent further decrease of their skeletal mass and preserve their BMD.

Autoimmune and clinical characteristics of type I diabetes in children with different genetic risk loads defined by HLA-DQB1 alleles. Childhood Diabetes in Finland Study Group

1. The impact of different genetic risk loads defined by HLA-DQB1 alleles on the autoimmune and clinical characteristics of 647 children and adolescents with recent-onset Type I diabetes was evaluated in a prospective population-based study. The subjects were divided into four groups based on HLA-DQB1 genotypes: DQB1*0302/0201 (high risk), *0302/x (moderate risk), *0201/y (low risk) and *z/z (decreased risk). 2. Close to two thirds (62.3%) of the subjects possessed a high or moderate risk genotype. A decreased frequency of positivity for islet cell antibodies (ICA) and insulin autoantibodies (IAA) (76.8% compared with 85.3%; P = 0.05, and 30.5% compared with 50.8%, P = 0.0006, respectively) but not of positivity for antibodies to the 65 kDa isoform of glutamate decarboxylase was observed in children with the DQB1*0201/y genotype compared with other children. Among ICA-negative subjects, those with the DQB1*0201/y genotype had higher serum C-peptide levels over the first 2 years after the diagnosis of Type I diabetes than those with other genotypes (P = 0.028). 3. Our data provide some evidence of HLA-DQB1-determined heterogeneity in the autoimmune and clinical characteristics of childhood Type I diabetes at the time of the clinical manifestation. This suggests differences between children with various HLA-DQB1 genotypes in the pace and/or intensity of the beta-cell destructive process leading to clinical Type I diabetes.

Exercise-induced increase in serum creatine kinase is modified by subsequent bed rest

This study was designed to find out if bed rest, which is known to markedly reduce peripheral lymph flow, immediately after strenuous exercise could affect the behaviour of creatine kinase activity (CK) in serum. Eleven endurance athletes performed an 18 km cross-country run, after which six of the subjects were placed in bed rest group (BR) for 23 hours, while a group of five control subjects maintained their normal habitual activity (C). After the bed rest all subjects performed a light jogging bout for 45 min. Seven hours after the exercise serum CK was increased threefold (p < 0.05) in both groups. During the next 16 hours serum CK increased further 30% in C (p < 0.05) but decreased (p < 0.05) in a similar magnitude in BR. Light jogging elicited a transient CK increase of 16% (p < 0.05) in C, but there was no change in BR. The fact that serum CK increased similarly in both groups during the first hours after the exercise shows that the transport of CK from muscles into circulation can be maintained for some hours despite absence of muscular activity. However, the later post-exercise serum CK response may be diminished by bed rest (effect of posture and/or lack of muscle function). The reduced response is also seen in the CK response to a repeated exercise. These observations suggest that a short-term physical inactivity (bed rest) may reduce both the lymphatic transport of CK and the release of enzyme from muscle fibres.

Poor beta-cell function after the clinical manifestation of type 1 diabetes in children initially positive for islet cell specific autoantibodies. The Childhood Diabetes in Finland Study Group

The prognostic significance of islet cell specific autoantibodies at the diagnosis of Type 1 (insulin-dependent) diabetes mellitus for the persistence of residual beta-cell function over the first 2 years of clinical disease was evaluated in a prospective population-based study. Seven hundred and eighty probands, aged 0.8-14.9 years, were examined for islet cell antibodies (ICA) and insulin autoantibodies (IAA), while 769 probands were studied for antibodies to glutamic acid decarboxylase (GAD65A). They were subsequently observed for 2 years. Lower serum C-peptide concentrations and higher requirement of exogenous insulin during the follow-up period were observed in the group of probands positive for at least one of the antibodies, especially for ICA or IAA. We conclude that the residual beta-cell function after the presentation of Type 1 diabetes is less in children initially positive for islet cell specific autoantibodies than in those testing negative at diagnosis. This might reflect possible heterogeneity in the pathogenesis of childhood diabetes. It also demonstrates that ICA and IAA negativity at the diagnosis of Type 1 diabetes is not associated with a smaller amount of functioning beta-cell mass, but the absence of antibodies probably reflects a slower beta-cell destructive process and a longer duration of preclinical disease.

Poor beta-cell function after the clinical manifestation of type 1 diabetes in children initially positive for islet cell specific autoantibodies. The Childhood Diabetes in Finland Study Group

The prognostic significance of islet cell specific autoantibodies at the diagnosis of Type 1 (insulin-dependent) diabetes mellitus for the persistence of residual beta-cell function over the first 2 years of clinical disease was evaluated in a prospective population-based study. Seven hundred and eighty probands, aged 0.8-14.9 years, were examined for islet cell antibodies (ICA) and insulin autoantibodies (IAA), while 769 probands were studied for antibodies to glutamic acid decarboxylase (GAD65A). They were subsequently observed for 2 years. Lower serum C-peptide concentrations and higher requirement of exogenous insulin during the follow-up period were observed in the group of probands positive for at least one of the antibodies, especially for ICA or IAA. We conclude that the residual beta-cell function after the presentation of Type 1 diabetes is less in children initially positive for islet cell specific autoantibodies than in those testing negative at diagnosis. This might reflect possible heterogeneity in the pathogenesis of childhood diabetes. It also demonstrates that ICA and IAA negativity at the diagnosis of Type 1 diabetes is not associated with a smaller amount of functioning beta-cell mass, but the absence of antibodies probably reflects a slower beta-cell destructive process and a longer duration of preclinical disease.

The effects of a 4-day march on the lower extremities and hormonal balance

The functional strength, flexibility, and ranges of motion of the lower extremities, as well as hormonal balance, estimated by urinary excretion of adrenaline and noradrenaline and serum determinations of testosterone and cortisol, were studied with six physically active army officers participating in a 4-day march totaling 185 km. Catecholamine excretion rates showed cumulatively increased sympathoadrenal stress, and the effects on serum testosterone and cortisol concentrations were minor. Also, leg measurements showed no signs of edema, decreases in flexibility, or decreases in functional strength. Most pain (75%) experienced by the subjects was located in the feet and caused by abrasions and blisters. Only a small portion of perceived pains (25%) was associated with muscle soreness. Serum creatine kinase activity was slightly (ca. 400-650%) increased during the marching days. Thus, soldiers who are in good physical condition and are accustomed to marching are able to walk four marathons on successive days, while carrying 10-kg backpacks, without any major adverse effects on the musculature of their lower extremities.

Ketoacidosis at the diagnosis of type 1 (insulin dependent) diabetes mellitus is related to poor residual beta cell function. Childhood Diabetes in Finland Study Group

The determinants of the degree of metabolic decompensation at the diagnosis of type 1 (insulin dependent) diabetes mellitus (IDDM) and the possible role of diabetic ketoacidosis in the preservation and recovery of residual beta cell function were examined in 745 Finnish children and adolescents. Children younger than 2 years or older than 10 years of age were found to be more susceptible to diabetic ketoacidosis than children between 2 and 10 years of age (< 2 years: 53.3%; 2-10 years: 16.9%; > 10 years: 33.3%). Children from families with poor parental educational level had ketoacidosis more often than those from families with high parental educational level (24.4% v 16.9%). A serum C peptide concentration of 0.10 nmol/l or more was associated with a favourable metabolic situation. Low serum C peptide concentrations, high requirement of exogenous insulin, low prevalence of remission, and high glycated haemoglobin concentrations were observed during the follow up in the group of probands having diabetic ketoacidosis at the diagnosis of IDDM. Thus diabetic ketoacidosis at diagnosis is related to a decreased capacity for beta cell recovery after the clinical manifestation of IDDM in children.

Training-induced protection and effect of terminated training on exercise-induced damage and water content in mouse skeletal muscles

Muscle swelling in connection with training-induced protection against exercise-induced damage and the disappearance of the protective adaptation after termination of training was studied in male NMRI-mice, aged 8 weeks at the beginning of the experiment. Mice were randomly assigned to several different treatment groups (training, training-exercise, exercise, detraining, detraining-exercise, together with their respective controls). Training and prolonged exercise sessions were performed by running uphill (6 degrees) on a motor-driven treadmill. Muscle damage was estimated by the total activity of beta-glucuronidase and water content from the red parts of m. quadriceps femoris (MQF), m. soleus (MS), m. rectus femoris (MRF), and from m. triceps brachii (MTB). Training-induced protection was observed in MS after only one week of training. In MQF the protection was incomplete after 1 and 4 weeks' training. In MS the protection disappeared already one week after the cessation of training. In MQF the training-induced protection persisted in part for one week but after four-week's detraining no protection was observed. The present results suggest that diminution of muscle swelling forms part of the adaptation of skeletal muscle in resisting exercise damage, and, vice versa, increased susceptibility to exercise damage, which follows the termination of training, is linked to muscle reswelling.

Does increased serum creatine kinase activity reflect exercise-induced muscle damage in rats?

To test a hypothesis that exercise-induced increase in serum creatine kinase activity and the concomitant necrotic muscle damage in unaccustomed rats may be interrelated phenomena, and that the first might largely be caused by changes in lymph flow, groups of rats were separately exposed to a swimming, combination of swimming and running, and running protocol. Their serum was then repeatedly analysed over a period of 72 h for creatine kinase activity, and their soleus and the red parts of quadriceps femoris muscles for beta-glucuronidase activity (damage marker) 72 h after the commencement of the experiment, i.e. at a moment when muscle damage is in the necrotic phase. The results clearly showed that serum creatine kinase activity may increase without concomitant muscle damage (swimming protocol) and that muscle damage may occur without a statistically significant increase in serum creatine kinase activity (running protocol). Swimming followed by running increased creatine kinase activity more strongly than the separate protocols. Muscle damage was of a similar magnitude after running and after the combined exercise. The present results indicate that serum creatine kinase activity in rodent exercise myopathy is an inadequate indicator of injury both quantitatively and qualitatively.

Running-induced muscle injury and myocellular enzyme release in rats

The relationships and time course of exercise-induced muscle damage, estimated by beta-glucuronidase activity and microscopy, to muscle swelling, estimated by muscle water content and microscopy, and to the serum activity of creatine kinase (CK) and the concentration of carbonic anhydrase III were studied in rats 2, 12, 48, and 96 h after 90 min of intermittent running uphill (+13.5 degrees) or downhill (-13.5 degrees) at a speed of 17 m/min. The injury was more pronounced in soleus after uphill running and in the red parts of quadriceps femoris and in the white part of vastus lateralis after downhill running, whereas triceps brachii was not damaged. Increase in muscle water content preceded the increase of beta-glucuronidase activity. Both running protocols similarly increased serum CK 2 h postexercise. After downhill running a second peak in serum CK was observed 48 h later. The CK changes were not in concert with the changes in muscle water content or beta-glucuronidase activity, suggesting that these responses may not be mechanistically (or causally) related.

Exercise-induced necrotic muscle damage and enzyme release in the four days following prolonged submaximal running in rats

Male Wistar rats were made to run uphill on a treadmill 5.5 degrees incline at 17 m min-1 for 4 h, and killed for muscle and serum sampling 2, 4, 12, 24, 48 or 96 h after the exertion. To estimate the degree of muscle damage, beta-glucuronidase activity, total protein concentration, water content and morphology were examined in the red parts of quadriceps femoris (MQF) and soleus (MS) muscles, the distal white part of the rectus femoris muscle (MRF) and the superficial part of triceps brachii muscle (MTB). Simultaneous serum samples were assayed for creatine kinase (CK) activity and carbonic anhydrase III (CA III) concentration. Fibre swelling and interstitial oedema were detected in MS at 4 h and in MQF at 12 h and typical histopathological changes, including inflammation and fibre necrosis, in both muscles 12-96 h post-exertion. beta-Glucuronidase activity, a quantitative marker of muscle damage, was increased in MS at 4 h, in MQF at 24 h and in MRF 48 h after the running. No increase occurred in MTB. Water and protein content increased or decreased respectively, faster in MS (2 h post-exercise) than in MQF (12 h) or MRF (12 h). Water content thus contributed to muscle damage by preceding the increase in beta-glucuronidase activity. Serum CK activity was increased 2, 4, and 48 h after the running. Changes in serum CA III concentration were rather similar to those in CK but were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Dissociation of the effects of training on oxidative metabolism, glucose utilisation and GLUT4 levels in skeletal muscle of streptozotocin-diabetic rats

The effects of long-term, moderate physical exercise on in vivo glucose uptake, levels of two glucose transporter proteins (GLUT1 and GLUT4) and activities of various key enzymes of energy metabolism were measured in skeletal muscle from streptozotocin-diabetic rats. Diabetes (12-16 weeks) reduced the in vivo glucose uptake (glucose metabolic index, GMI) in muscle containing mainly type I fibres by 55% but had no effect in muscles containing mainly type IIa and IIb fibres. GMI was increased in the diabetic white skeletal muscle (mainly type IIb fibres) by more than 120%. In contrast to the complex changes in GMI, GLUT4 levels were reduced in all types of skeletal muscle from diabetic rats with no change in GLUT1 levels. Exercise training had no effects on GMI or the glucose transporter levels. Streptozotocin induced diabetes significantly reduced the oxidative capacity of skeletal muscle assayed as the activities of citrate synthase, succinate dehydrogenase and cytochrome c oxidase. Training increased the activities of oxidative enzymes, with this increase being more prominent in the diabetic animals. The present data indicate that long-term streptozotocin-induced diabetes decreases oxidative metabolic capacity and GLUT4 protein levels in skeletal muscle, but that the changes of glucose transport largely depend on the fibre type composition. Moderate training fully reverses the effect of insulinopenia and hyperglycaemia on muscle oxidative metabolism. In contrast to the previous suggestions, the expression of GLUT4 is not correlated with the capacity of oxidative metabolism in skeletal muscle of streptozotocin-diabetic rats.

Prolactinemia in adolescent males surviving malignancies in childhood: impaired dating activity

A relationship appears to exist between prolactin metabolism and psychosexual development. We studied pubertal stage, testicular size, and serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, thyroxine, thyroid-stimulating hormone (TSH), and prolactin concentrations in 94 adolescent males who had survived malignancies in childhood. Of the patients, 22% had elevated serum prolactin, > 300 mU/L. In multivariate analysis, the only therapeutic agents or treatments found to be independently associated with prolactin concentration were cisplatin and cytosine arabinose. Administration of cisplatin was associated with an increase of 55 m U/L (p < 0.01) and that of cytosine arabinoside with an increase of 23 mU/L (p < 0.01) in serum prolactin concentration. Serum prolactin concentration correlated with serum FSH (r = 0.26, p = 0.16) and LH (r = 0.30, p = 0.005). In 45 of the patients 10 criteria of psychosexual development were evaluated using a personal, semi-structured, and psychodynamically-oriented interview. A significant inverse relation existed between serum prolactin concentration and dating with the opposite sex (p = 0.008); none of the patients with elevated serum prolactin were dating. We conclude that even a slight elevation of serum prolactin above normal is associated with or may be reflected in the psychosexual development of adolescent males who have survived malignancies in childhood.

Coronary pressure determines regional glucose uptake in the left ventricular wall of the heart

The effect of coronary and intraventricular pressures on the glucose uptake and its transmural distribution was studied in isolated, beating rat heart perfused using the Langendorff procedure. Left ventricular glucose uptake measured by the deoxyglucose method, and the effect of coronary (aortic) pressure was dissociated from intraventricular pressure development by draining the left ventricle. Left ventricular glucose uptake was 2.6 +/- 0.1 mumols/min per g protein (mean +/- S.E.M.) and 35 +/- 6% higher (P less than 0.001) in the subendocardium than in the subepicardium under control conditions (aortic pressure 80 cm H2O, non-drained). Elimination of the intraventricular pressure development caused no significant change in the total left ventricular glucose uptake or its transmural distribution. Increase in the aortic pressure to 150 cmH2O accelerated glucose uptake in non-drained and drained hearts by 57-75%. The increase in the glucose uptake was more pronounced in the subepicardial layer than in the subendocardial layer, so that the transmural gradient decreased by 27-32% (P less than 0.001) in non-drained and drained hearts. The results indicate that in Langendorff-perfused heart the effect of aortic pressure on the total glucose uptake and its transmural distribution across the left ventricular wall is not mediated through intraventricular pressure development, but through the coronary pressure.

Muscle enzyme adaptations to added load during training and nontraining hours in rats

The effects of added load (20% of body mass) on the selected enzyme activities of red and white quadriceps femoris (QF), soleus, and gastrocnemius muscles of rats were studied. The rats were divided into sedentary control (SC), sedentary control with added load (SC+AL), endurance training (ET), and endurance training with added load (ET+AL) groups (n = 10 rats/group). After 6 wk, the SC+AL group had 57% higher (P less than 0.001) beta-glucuronidase (beta-GU) activity and 24% lower (P less than 0.05) citrate synthase activity in white QF than SC. Citrate synthase activity was also decreased in red QF (P less than 0.05) after the added load was used during nontraining hours. The training with added load induced similar but more pronounced changes than normal endurance training, especially in white QF. The ET+AL group demonstrated higher citrate synthase activity in white QF (P less than 0.001) and gastrocnemius (P less than 0.01) and higher malate dehydrogenase activity (P less than 0.05) and beta-GU activity (P less than 0.001) in white QF than the ET group. ET+AL rats also had higher phosphofructokinase (P less than 0.01) and lower creatine kinase (P less than 0.001) activity in white QF than ET rats. In conclusion, the added load without training had minor adaptive influences on muscles. The added load during training hours seemed to be an effective means of influencing the activation and adaptation in muscles that contain fast glycolytic fibers.

Regional differences of substrate oxidation capacity in rat hearts: effects of extra load and endurance training

Male rats, aged 17 weeks at the end of experiments, were divided into four groups. Two groups lived in normal cage conditions with or without extra load (20% of the body weight) and two groups were trained by running with or without extra load for 8 weeks. Oxidation rates of succinate, glutamate + malate, palmitoylcarnitine, and pyruvate, and the activities of lactate dehydrogenase, citrate synthase, isocitrate dehydrogenase and cytochrome oxidase were measured in homogenates of the right ventricle and in those of the subendocardial and subepicardial layers of the left ventricle. Oxidation rates of succinate and palmitoylcarnitine tended to be higher in the subendocardium than in the subepicardium of sedentary control animals (p less than 0.1 and p less than 0.05, respectively). Transmural differences of succinate and palmitoylcarnitine oxidation rates were even more clear after running training (p less than 0.01 and p less than 0.05, respectively), after carrying extra load (p less than 0.001 and p less than 0.001, respectively) and after training carrying extra load (p less than 0.001 and p less than 0.05, respectively). Training also enhanced pyruvate oxidation rate in the subendocardium. Oxidation rates of all substrates were lower in the right ventricle than in the left ventricle. In control animals there were no regional differences in the myocardial enzyme activities and the training- or extra-load-induced changes were modest compared with the changes in the oxidation rates. The most significant change was the training-induced enhancement in the lactate dehydrogenase activity of the subendocardium (p less than 0.001 vs subepicardium). These results show greater subendocardial than subepicardial oxidation rates of certain substrates in the normal heart. These results also suggest that the myocardium adapts to increased work by increasing the subendocardial oxidation rate of some but not all substrates, indicating further that there may be qualitative mitochondrial differences in the different regions of the heart.

Effect of chronic exercise on glucose uptake and activities of glycolytic enzymes measured regionally in rat heart

Regional glucose uptake in perfused hearts, and the activities of several glycolytic enzymes contributing to the glucose metabolism in perfused and nonperfused hearts were studied in male and female rats after 8-9 weeks of swimming training. The left ventricular glucose uptake showed a transmural gradient in the sedentary animals, the subendocardial uptake being 30% and 12% higher than that of the subepicardial layer in the males and females, respectively. Swimming exercise abolished the left ventricular glucose uptake gradient in male rats, and in female rats an opposite gradient was found, the subepicardial uptake being 23% higher than the subendocardial uptake. The activities of phosphofructokinase and 3-phosphoglyceraldehyde dehydrogenase also showed transmural gradients in the left ventricles. Training did not abolish these gradients. Training-induced changes in the activities of phosphofructokinase, 3-phosphoglyceraldehyde dehydrogenase, pyruvate kinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, citrate synthase, and malate dehydrogenase were found in certain sites of the myocardium. Perfusion of isolated hearts for 50 min with insulin-containing Krebs-Ringer buffer especially affected the activities of phosphofructokinase, lactate dehydrogenase, and citrate synthase, increasing these activities in the left ventricles and decreasing them in the atria. These results indicate that there are regional differences between male and female rats in the cardiac glucose uptake rate after swimming training.

Effects of training on regional substrate oxidation in the hearts of ageing rats

23-month-old male rats were trained by running for 20 weeks. The oxidation rates of succinate, glutamate+malate, palmitoylcarnitine, and pyruvate and the activities of lactate dehydrogenase, citrate synthase, isocitrate dehydrogenase and cytochrome oxidase were measured in the subendocardium and subepicardium and in the right ventricle. Regional differences of substrate oxidation rates in the myocardium of old sedentary or trained rats were less than in young rats, suggesting that regional differences in the cardiac work load disappear during ageing. Training did not improve oxidation rates, in contradiction to some previous results.