Arbuscular mycorrhizas are present on Spitsbergen.

A previous study of 76 plant species on Spitsbergen in the High Arctic concluded that structures resembling arbuscular mycorrhizas were absent from roots. Here, we report a survey examining the roots of 13 grass and forb species collected from 12 sites on the island for arbuscular mycorrhizal (AM) colonisation. Of the 102 individuals collected, we recorded AM endophytes in the roots of 41 plants of 11 species (Alopecurus ovatus, Deschampsia alpina, Festuca rubra ssp. richardsonii, putative viviparous hybrids of Poa arctica and Poa pratensis, Poa arctica ssp. arctica, Trisetum spicatum, Coptidium spitsbergense, Ranunculus nivalis, Ranunculus pygmaeus, Ranunculus sulphureus and Taraxacum arcticum) sampled from 10 sites. Both coarse AM endophyte, with hyphae of 5-10 µm width, vesicles and occasional arbuscules, and fine endophyte, consisting of hyphae of 1-3 µm width and sparse arbuscules, were recorded in roots. Coarse AM hyphae, vesicles, arbuscules and fine endophyte hyphae occupied 1.0-30.7, 0.8-18.3, 0.7-11.9 and 0.7-12.8% of the root lengths of colonised plants, respectively. Principal component analysis indicated no associations between the abundances of AM structures in roots and edaphic factors. We conclude that the AM symbiosis is present in grass and forb roots on Spitsbergen.

Wild-type MIC distributions of four fluoroquinolones active against Mycobacterium tuberculosis in relation to current critical concentrations and available pharmacokinetic and pharmacodynamic data.

OBJECTIVES: To describe wild-type distributions of the MIC of fluoroquinolones for Mycobacterium tuberculosis in relation to current critical concentrations used for drug susceptibility testing and pharmacokinetic/pharmacodynamic (PK/PD) data. METHODS: A 96-stick replicator on Middlebrook 7H10 medium was used to define the MICs of ciprofloxacin, ofloxacin, moxifloxacin and levofloxacin for 90 consecutive clinical strains and 24 drug-resistant strains. The MICs were compared with routine BACTEC 460 susceptibility results and with MIC determinations in the BACTEC MGIT 960 system in a subset of strains using ofloxacin as a class representative. PK/PD data for each drug were reviewed in relation to the wild-type MIC distribution. RESULTS: The wild-type MICs of ciprofloxacin, ofloxacin, moxifloxacin and levofloxacin were distributed from 0.125 to 1, 0.25 to 1, 0.032 to 0.5 and 0.125 to 0.5 mg/L, respectively. The MIC data correlated well with the BACTEC 960 MGIT and BACTEC 460 results. PD indices were the most favourable for levofloxacin, followed by moxifloxacin, ofloxacin and ciprofloxacin. CONCLUSIONS: We propose S (susceptible)

Growth hormone-dependent insulin-like growth factor binding protein is a major determinant of bone mineral density in healthy men.

To establish the major determinants of bone mass, we assessed relationships between bone mineral density (BMD) and height, weight, body mass index (BMI), muscle strength, physical capacity (VO2max), body composition, serum concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH), the GH-dependent IGF binding protein (IGFBP-3), testosterone, sex hormone binding globulin (SHBG), osteocalcin, and parathyroid hormone (PTH) in 38 healthy men between 25 and 59 years of age. Values of BMD at all sites (total body, lumbar spine, and hip) were strongly correlated with IGFBP-3 (r = 0.51-0.64, p < 0.001 at all sites), and total-body BMD was also significantly correlated with IGF-I (r = 0.43, p = 0.01). BMD measurements of the total body and of the different sites of the hip were negatively correlated with age and positively with weight, BMI, muscle strength, VO2max, and fat-free weight. IGF-I and IGFBP-3 were both positively related to muscle strength and VO2max. In a stepwise forward multiple-regression analysis, the best model was obtained for the femoral neck, where IGFBP-3, GH, PTH, age, IGF-I, and BMI explained 77% of the variation in BMD. The partial regression coefficients of IGFBP-3, PTH, and BMI were all positive, whereas age, GH, and IGF-I were negatively correlated with BMD. In summary, IGFBP-3 correlated better with BMD than any other study parameter. The findings indicate that GH is of importance for bone mass and suggest that IGFBP-3 not only reflects the integrated GH secretion but also has a direct role in the endocrine regulation of bone metabolism.

Regulation of interleukin-6 secretion from mononuclear blood cells by extracellular calcium.

Interleukin-6 (IL-6) is known to enhance osteoclast recruitment, and thereby bone resorption. Thus, IL-6 has been proposed to mediate hypercalcemia in multiple myeloma and the enhanced osteoclastic activity seen in postmenopausal osteoporosis. We recently reported that the calcium concentration in plasma affects IL-6 secretion from mononuclear blood cells. To investigate the underlying mechanism, we have studied the effect of calcium on IL-6 formation in mononuclear blood cells ex vivo and in vitro. Thirteen healthy volunteers were given 1 g of calcium orally after overnight fasting. Plasma levels of ionized calcium (pCa2+) and serum levels of parathyroid hormone (sPTH) were measured after 2 and 4 h, with all subjects still fasting. After 2 h, pCa2+ was increased and sPTH decreased in all 13 persons. IL-6 secretion ex vivo from mononuclear blood cells drawn 4 h after calcium intake was increased 185% as compared with IL-6 secretion from cells drawn just before calcium intake. In control experiments without calcium intake, there was no alteration in pCa2+ and no effect on IL-6 secretion from mononuclear blood cells. In vitro studies revealed that stimulation of isolated mononuclear blood cells with physiological concentrations of calcium dose-dependently increased IL-6 secretion with an estimated EC50 at 1.2 mM Ca2+. No effect on the IL-6 secretion was seen following treatment of the isolated mononuclear blood cells with PTH or calcitonin. These observations demonstrate that the plasma calcium concentration affects IL-6 secretion from mononuclear blood cells. The in vitro data indicate the involvement of a direct calcium sensing mechanism. These findings might have implications in hypercalcemia and should also be borne in mind when considering the role of cytokines in osteoporosis.

Growth hormone (GH)-deficient men are more responsive to GH replacement therapy than women.

Thirty-six patients with adult-onset GH deficiency (GHD) were examined before and after 9 months of treatment with recombinant GH. The study was conducted as a double blind, placebo-controlled, 21-month trial with a cross-over design, with each treatment period lasting for 9 months. The same dose, adjusted for body surface area, was given to men (n = 21) and women (n = 15), and the effects on body composition and biochemical parameters were evaluated with respect to gender. The extent of GHD, assessed before therapy from basal GH secretion and GH release in response to provocative tests, did not differ between the two groups. The men, however, had higher serum insulin-like growth factor I concentrations than the women (mean +/- SD, 126 +/- 71 vs. 61 +/- 32 micrograms/L; P = 0.0003), less body fat, and greater lean body mass. Upon treatment, insulin-like growth factor I concentrations increased more in men than in women (by 305 +/- 136 and 198 +/- 96 micrograms/L, respectively; P = 0.02). The men lost more body fat than the women (7.4 +/- 4.1% vs. 3.3 +/- 3.8%; P = 0.002), whereas the difference in gain in lean body mass failed to reach statistical significance. Serum levels of total cholesterol, low density lipoprotein cholesterol, apolipoprotein B, and plasminogen activator inhibitor-1 decreased in the male group (P = 0.003, P = 0.03, P = 0.0009, and P = 0.01, respectively), but not in the females. Serum markers of bone formation, namely osteocalcin, procollagen type I, bone-specific alkaline phosphatase, and a marker of bone resorption, telopeptide of collagen type I, increased more markedly in men than in women. Lipoprotein(a) increased to a similar extent in the male and female groups. The data demonstrate that men and women with GHD display marked differences in their responsiveness to GH replacement therapy. These differences should be taken into consideration when optimizing the treatment of GHD patients.

Effects of growth hormone and insulin-like growth factor I in men with idiopathic osteoporosis.

Injections with growth hormone (GH) or insulin-like growth factor I (IGF-I) have been proposed for anabolic therapy in osteoporosis. In a cross-over study, 12 men with idiopathic osteoporosis received daily subcutaneous injections of GH (2 IU/m2) or IGF-I (80 micrograms/kg) for 7 days with 12 weeks of wash-out. Serum levels of procollagen type I increased by 29% following treatment with GH (P < 0.001) and by 43% with IGF-I (P < 0.001 compared with pretreatment levels; P < 0.05 compared with GH injections), whereas both treatments rendered a 20% increase in osteocalcin concentrations (P < 0.001), indicating enhanced bone formation. There was also evidence of stimulated bone resorption, as the urinary levels of deoxypyridinoline increased by 44% following GH injections (P < 0.001) and by 29% following IGF-I (P < 0.001), and there were 28% higher serum concentrations of IGF-I after GH than after IGF-I injections. Although markers of bone metabolism increased under both treatments, comparison of the treatments suggests that IGF-I enhanced formation of collagen type I more than did GH. Furthermore, the stimulation of bone resorption was detected as soon as 4 days after the initiation of GH injections. Some of the differences might be dose-dependent, but could also indicate separate mechanisms at the cellular level.

Gender differences in the effects of long term growth hormone (GH) treatment on bone in adults with GH deficiency.

We recently observed that among patients with GH deficiency due to adult-onset hypopituitarism, men responded with a greater increase in serum levels of insulin-like growth factor I (IGF-I) and biochemical markers of bone metabolism than women when the same dose of recombinant human GH (rhGH) per body surface area was administered for 9 months. In the present study, 33 of the 36 patients in the previous trial (20 men and 13 women) continued therapy for up to 45 months. The dose of rhGH was adjusted according to side-effects and to maintain serum IGF-I within the physiological range. This resulted in a significant dose reduction in the men; consequently, the women received twice as much rhGH as the men (mean +/- SD, 1.9 +/- 1.1 vs. 1.0 +/- 0.6 U/day; P < 0.01). The increases in serum IGF-I levels and serum biochemical markers of bone metabolism were similar in men and women with these doses. The total bone mineral content (BMC) was increased after 33 and 45 months of treatment up to 5.1% (P = 0.004 and 0.0001). Bone mineral density (BMD), BMC, and the area of the femoral neck and the lumbar spine were also significantly increased after 33 and 45 months of treatment. When analyzed by gender, total body BMC, femoral neck BMD and BMC, and spinal BMC were significantly increased in males, but not in females (P < 0.05-0.01). In conclusion, rhGH treatment continued to have an effect on bone metabolism and bone mass for up to 45 months of therapy. The changes in bone mass were greater in the men, although they received lower doses of rhGH than the women. The results indicate that the sensitivity to GH in adult patients with GH deficiency is gender dependent.

Reduced serum levels of the growth hormone-dependent insulin-like growth factor binding protein and a negative bone balance at the level of individual remodeling units in idiopathic osteoporosis in men.

Idiopathic osteoporosis in younger individuals could be related to reduced bone formation rather than increased bone resorption, and disturbances in GH or insulin-like growth factor (IGF)-I production could be involved in its pathogenesis. In the present study, men with idiopathic osteoporosis were compared with healthy men, with respect to bone histomorphometry and to serum levels of IGF-I, IGF-II, IGF binding protein (IGFBP)-2 and IGFBP-3, and 24-h urinary excretion of GH. Mean wall thickness was reduced in the patients (48.3 +/- 7.2 vs. 61.7 +/- 5.4 microns, P < 0.001). Also, resorption depth was decreased, albeit to a lesser degree (54.4 +/- 3.8 vs. 60.7 +/- 5.3 microns, P < 0.01), thus creating a pronounced negative balance (-6.04 +/- 9.8 vs. 0.96 +/- 3.2 microns, P < 0.05). In the patients, serum concentrations of IGFBP-3 were reduced, compared with controls, with a 46% lower mean value; whereas levels of IGF-I, IGF-II, IGFBP-2, and GH were similar in the two groups. Thus, there was a significant negative balance caused by a pronounced decrease in wall thickness in men with idiopathic osteoporosis. The finding of low IGFBP-3 levels in these patients is interesting, in view of previous clinical and experimental findings, but its pathophysiological significance remains to be determined.

Determination of body composition--a comparison of dual-energy x-ray absorptiometry and hydrodensitometry.

Determination of body composition by dual-energy x-ray absorptiometry (DEXA) was evaluated in healthy men, by using underwater weighing (UWW), skinfold thickness measurement, and bioimpedance analysis. There were strong correlations between percent body fat obtained by all techniques, but DEXA gave significantly lower values (P < 0.001). The influence of differences in bone mineral density (BMD) on fat content determined by UWW was also studied. The individual differences between UWW and DEXA fat estimates were calculated and there was a negative correlation with BMD (r = -0.50, P < 0.05). There was also a negative correlation between body fat by UWW and BMD (r = -0.71, P < 0.01) in the subjects with lowest fat by DEXA, indicating that high or low BMD gave false values by UWW. In conclusion, DEXA and UWW provide complementary information and a combination of these techniques seems to offer new opportunities in evaluations of body composition.

Evaluation of modified multicompartment models to calculate body composition in healthy males.

The purpose of this study was to develop flexible and accurate multicompartment equations to calculate body composition and compare the results with methods using common two-compartment equations. Twenty-two healthy male volunteers 22-59 y of age were studied. Body volume was measured by underwater weighing (UWW) or with a skinfold caliper, bone mineral by dual-energy X-ray absorptiometry (DXA), and body water by bioelectrical impedance analysis (BIA). The percentage of water and bone mineral in fat-free mass (FFM) had a significant effect on the difference in percentage fat obtained by the two-compartment model compared with a four-compartment model. FFM density was negatively (r = -0.76, P < 0.001) and percentage water in FFM was positively correlated with age (r = 0.75, P < 0.001). The three-compartment model based on field-adapted methods (skinfold thickness + BIA) to calculate percentage body fat correlated significantly with the more complex four-compartment model (UWW + BIA + DXA; r = 0.95, P < 0.001). The advantages of three- and four-compartment equations are that they compensate for differences in body content of bone mineral and water.

Detection and identification of fungi in blood using broad-range 28S rDNA PCR amplification and species-specific hybridisation.

The aim of the present study was to develop a PCR-based method to detect and identify fungi directly from human venous blood. We used broad-range PCR primers that targeted a part of the large subunit 28S rRNA genes. To obtain species-specific hybridisation probes, type strains of Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans were PCR amplified, and the amplicons were analysed by gene sequencing. Based on the sequence analysis, species-specific probes that targeted variable regions were designed and used in hybridisation analyses. Between 2 to 10 fungal cells/ml of spiked blood samples could be detected and correctly identified to species. We applied the technique to blood samples obtained from two patients with or two patients without verified candidaemia. The three samples of candidaemia patients were correctly identified to species level, and those of the negative patients remained negative. This method is a potential tool for diagnosis of systemic invasive candidiasis.

Insulin-like growth factor I enhances the formation of type I collagen in hydrocortisone-treated human osteoblasts.

We have studied the effect of insulin-like growth factor I (IGF-I) on the formation of osteocalcin and type I collagen in isolated human osteoblasts. IGF-I at and above 0.1 nM stimulated the formation of type I collagen as measured by the type I procollagen carboxyterminal peptide (PICP), in human osteoblasts, incubated for 72 hrs in serum free conditions. The secretion of osteocalcin was not affected by IGF-I while 1,25(OH)2vitamin D3 significantly enhanced the formation of osteocalcin. When human osteoblast-like cells were incubated with hydrocortisone (1 microM), a significant decrease in the release of both PICP and osteocalcin was seen. Addition of IGF-I to human osteoblasts also treated with hydrocortisone normalized the PICP-formation but did not affect the suppressed osteocalcin-formation. These data indicate that IGF-I reverses selective effects of hydrocortisone on bone.

Candidaemia in Sweden: a nationwide prospective observational survey.

A prospective observational nationwide investigation was performed from September 2005 to August 2006 to study the epidemiology of candidaemia in Sweden. From 385 patients, 403 isolates were recovered, yielding an incidence of 4.2 cases per 100 000 inhabitants. Candida albicans was the most common species (61%), followed by Candida glabrata (20%) and Candida parapsilosis (9%). The rates of resistance to fluconazole were ≤ 1% in C. albicans and 6-29% in non-albicans species other than C. glabrata and Candida krusei. Resistance to voriconazole was rare, except for C. glabrata and C. krusei. Only three isolates had reduced susceptibility to amphotericin B, and one had reduced susceptibility to caspofungin.

Gender difference in growth hormone response in adults.

Several trials with growth hormone (GH) replacement therapy in adults with GH deficiency have been conducted during the last 10 years. Beneficial effects of treatment on bone density, physical capacity, body composition, lipid profile and quality of life have been reported. It has long been known that GH secretion is greater in women than in men, despite similar reference ranges of serum insulin-like growth factor (IGF)-I in adult men and women. It has also been reported that sex steroids influence not only GH secretion but also the local synthesis of IGF-I in target tissues and the expression of the GH receptor in various other tissues. However, it has been acknowledged only recently that there is a clinically significant gender difference in the response to GH treatment in adults with GH deficiency and, consequently, a need to adjust the dose of recombinant human GH (rhGH). We report the results of a placebo-controlled study in 36 men and women with GH deficiency who received the same dose of rhGH per body surface area (1.25 U/m2 per day) for 9 months. We observed significantly greater responses in male patients than in female patients with regard to the changes in serum levels of IGF-I, body composition and biochemical markers of bone metabolism. When these patients continued to receive GH replacement therapy for an additional 24 months, the dose of rhGH was adjusted to the serum levels of IGF-I. As a result, the dose administered to the male patients was reduced to nearly half that given to the female patients (1.0 vs 1.9 U/day) and the serum levels of IGF-I and of biomarkers of bone turnover increased to the same extent in patients of both sexes. However, an increase in bone density of the hip and the lumbar spine after a total of 33 months of rhGH treatment was observed only in the male patients; no significant changes in bone density were found in the female patients. The reason for the observed difference in GH response between men and women with GH deficiency is not known, although the different sex steroid pattern cannot be excluded as a contributing factor.

Different elimination of circulating IgA immune complexes in rat and guinea pig. Blood clearance, organ distribution and cellular uptake in the liver.

Soluble IgA immune complexes, formed between 125I-labelled dinitrophenyl-conjugated human serum albumin and mouse IgA anti-dinitrophenyl antibodies (MOPC315), were given intravenously to rats and guinea pigs. Blood clearance kinetics and organ distribution of radioactivity were measured after 15 min. Radioactivity was quantified in isolated parenchymal cells, Kupffer cells (KCs) and liver endothelial cells. IgA complexing did not affect the antigen blood clearance kinetics in either species. In rats, IgA increased the total hepatic antigen uptake, owing to a vast increase in the uptake by parenchymal cells. No IgA-mediated effect could be shown in KCs, still about 40-50% of the hepatic uptake was confined to KCs. In guinea pigs there was also an IgA-mediated increase in hepatic uptake, but here the increase could be ascribed to the KCs alone.

IgG immune complex binding to and activation of liver cells. An in vitro study with IgG immune complexes, Kupffer cells, sinusoidal endothelial cells and hepatocytes.

BACKGROUND/AIMS: The aim was to study IgG immune complex (IC) binding to isolated hepatocytes, Kupffer cells (KCs) and sinusoidal endothelial cells (SECs). Further, we wished to analyze the capacity of IgG ICs to induce release of reactive oxygen metabolites by the IC-binding liver cells. METHODS: ICs were formed between (125)I-tyramine-cellobiose-labelled dinitrophenyl-conjugated human serum albumin ((125)I-TC-DNP(10)HSA) and polyclonal rabbit IgG antibodies. Binding of ICs to different rat liver cells in suspension was studied at 4 degrees C. Production of reactive oxygen metabolites was measured by luminol-enhanced chemiluminescence at 37 degrees C. RESULTS: IgG mediated binding of (125)I-TC-DNP(10)HSA to both KCs and SECs, but not to hepatocytes. The binding showed saturation kinetics and was blocked by an excess of unlabelled IgG-ICs. IgG-ICs activated KCs, but not SECs, to a chemiluminescence response. CONCLUSIONS: Both KCs and SECs bind IgG-ICs in vitro, probably via Fc receptor interaction. IgG-ICs activate KCs to produce reactive oxygen metabolites. The binding of IgG-ICs to isolated hepatocytes is small.

Decreased estradiol levels and free androgen index and elevated sex hormone-binding globulin levels in male idiopathic osteoporosis.

Estrogen deficiency is an important pathogenetic factor in female osteoporosis, and androgens are known to have anabolic effects on bone. In this study we have compared 12 men with idiopathic osteoporosis, age 27-55 years, with 12 age-matched men, with respect to serum levels of sex steroids, biochemical markers of bone turnover, bone density, and body composition. All subjects showed values within the normal range for all hormonal parameters. The patient group compared with the controls had significantly lower serum levels of estradiol (71 +/- 13 versus 85 +/- 14 pmol/liter, P < 0.03); estradiol/sex hormone-binding globulin (SHBG) ratio (22.4 +/- 12.1 versus 39.5 +/- 18.6 pmol/mg, P < 0.02); free androgen index (51.0 +/- 19.4 versus 74.1 +/- 33.1%, P < 0.05); and higher SHBG (3.7 +/- 1.6 versus 2.5 +/- 1.0 mg/liter; P < 0.04). The men with idiopathic osteoporosis had significantly lower body mass index (23.2 +/- 2.8 versus 25.9 +/- 3.3 kg/m2, P < 0.05); and a tendency to lower percentage of total body fat (14.2 +/- 5.5 versus 18.6 +/- 6.0%; P < 0.10) than the controls. Regression analyses revealed that bone mineral density in femoral neck correlated significantly and positively with the ratio estradiol/SHBG (r = 0.67; P < 0.04) and negatively with SHBG concentrations (r = -0.63; P < 0.04) in the group of patients. These findings could represent a pathogenetic mechanism in male idiopathic osteoporosis.

The bone mineral density in acquired growth hormone deficiency correlates with circulating levels of insulin-like growth factor I.

Insulin-like growth factor I (IGF-I) is an important anabolic factor for osteoblasts in vitro. Low plasma levels of IGF-I have been observed in young men with osteoporosis. In the present study, we have studied bone mineral density (BMD) and the circulating levels of IGF-I and growth hormone (GH) in adults with acquired GH deficiency. BMD was determined by dual-energy x-ray absorptiometry in 17 men and 12 women (age 27-54 years). Spinal BMD was positively correlated with the plasma levels of IGF-I (r = 0.43, P = 0.019), with the median of GH values obtained by repeated sampling at night (r = 0.43, P = 0.0019), and with the peak of GH values during GHRH provocation test (r = 0.49, P = 0.039). The total BMD was positively related to plasma IGF-I and median of GH values, but not to peak GH by GHRH provocation. In a multiple regression analysis model, IGF-I, peak GH by GHRH provocation test and duration of GH deficiency explained 49% of the variation in spinal BMD. As compared to healthy controls, total, but not spinal, bone mass was lower in men with GH deficiency, but no clinical symptoms of osteoporosis were observed. The positive relationships between BMD and circulating IGF-I and other indices of GH secretion suggest that IGF-I has an endocrine effect on bone mass.