Tadalafil increases muscle capillary recruitment and forearm glucose uptake in women with type 2 diabetes.

AIMS/HYPOTHESIS: Recent evidence suggests that reduced synthesis of nitric oxide in endothelial cells, i.e. endothelial dysfunction, contributes to the impaired action of insulin in the vasculature of patients with type 2 diabetes. We investigated whether selective inhibition of phosphodiesterase-5 by tadalafil has beneficial effects on peripheral microcirculation and glucose uptake in these patients. METHODS: We enrolled seven postmenopausal women with type 2 diabetes and ten age-matched healthy women as controls in a placebo-controlled study to evaluate the acute metabolic effects of tadalafil. We performed microdialysis and blood flow measurements in muscle, and sampled arterial and deep venous blood before and after a single dose of tadalafil 20 mg or placebo. Circulating glucose and insulin levels, muscle capillary recruitment as reflected by permeability surface area for glucose (PS(glu)) and forearm glucose uptake were measured. RESULTS: In women with type 2 diabetes, but not in the control group, tadalafil induced increases in the incremental AUC for PS(glu) (tadalafil vs placebo 41 +/- 11 vs 4 +/- 2 ml [100 g](-1) min(-1), p < 0.05) and forearm glucose uptake (46 +/- 9 vs 8 +/- 4 micromol [100 g](-1) min(-1), p < 0.05). The variable that best predicted forearm glucose uptake was PS(glu), which explained 70% of its variance. However, fasting glucose and insulin concentrations were similar following treatment with placebo or tadalafil in the two groups. CONCLUSIONS/INTERPRETATION: This study suggests that tadalafil evokes positive metabolic effects in insulin-resistant women with type 2 diabetes.

Repeated measurements of 11ß-HSD-1 activity in subcutaneous adipose tissue from lean, abdominally obese, and type 2 diabetes subjects--no change following a mixed meal.

The aim of this study was to measure 11ß-HSD-1 activity in subcutaneous adipose tissue by an ex vivo method in three subgroups; lean, obese, and type 2 diabetes subjects, both in the fasting state and after a mixed meal and to determine the variability and reproducibility of this method. Eighteen subjects were investigated; 6 lean, 6 abdominally obese, and 6 type 2 diabetes subjects (BMI 22 ± 1, 30 ± 3 and 31 ± 3 kg/m², respectively). Needle biopsies were taken repeatedly and an index of 11ß-HSD-1 activity was measured as percent conversion of (3)H-cortisone to (3)H-cortisol/100 mg tissue. For two separate biopsies taken in the fasting state on the same day, the within subjects CV was 16% and the between CV was 36% for 11ß-HSD-1 activity for all subjects. For two biopsies taken in the fasting state at two different days, the total within subjects CV was 38% and the between subjects CV was 46%. Lean subjects had lower 11ß-HSD-1 activity (4.8 ± 1.5% conversion of ³H-cortisone to ³H-cortisol/100 mg tissue) than both obese (14.4 ± 1.6% conversion, p<0.01) and type 2 diabetes subjects (11.7 ± 1.9% conversion, p<0.05) in the fasting state. There was no effect of a meal on 11ß-HSD-1 activity in any of the three groups. The conclusions from this study are: 1) the variation coefficient for the ex vivo adipose tissue 11ß-HSD-1 activity method was ∼25% for repeat measures within subjects; 2) food intake had no major impact on enzyme activity; and 3) 11ß-HSD-1 activity in subcutaneous adipose tissue was significantly increased in obese subjects with or without T2DM compared to lean subjects without diabetes.

Irreducible memory function and slow dynamics in disordered systems.

We show how the irreducible memory function can be obtained in a rather straightforward way, and that it can be expressed in terms of two contributions representing two parallel decay channels. This representation should be useful for treating systems with a slow time dependence and where eventually some internal degrees of freedom enters in the relaxation process, and cuts off an underlying ideal ergodic to nonergodic transition. We also show how the irreducible memory function under certain mild conditions defines a regenerative stochastic process, or a two level stochastic system. This leads to a picture with dynamical heterogeneities, where the statistical properties asymptotically are ruled by limit processes. This can explain the universal behavior observed in many glass-forming systems.

Comparison of two hyaluronan drugs and placebo in patients with knee osteoarthritis. A controlled, randomized, double-blind, parallel-design multicentre study.

OBJECTIVE: To compare the efficacy and safety of intra-articular injections of two different hyaluronan preparations and placebo in patients with knee osteoarthritis. METHODS: In a randomized, patient- and observer-blind, placebo-controlled and multicentre trial with parallel groups, 210 patients, aged 60 yr or above, with knee osteoarthritis were included in a per protocol analysis. The patients were treated with three injections, once weekly, of either native high-molecular-weight hyaluronan (Artzal((R))) or cross-linked hyaluronan (Synvisc((R))) or with placebo and were followed for 52 weeks. The primary efficacy measures were weight-bearing pain during study weeks 0-26 and the duration of clinical benefit measured with Kaplan-Meier survival analysis for weeks 0-52. The secondary outcome measures were resting and maximum pain, Lequesne index, WOMAC (Western Ontario and McMaster University Osteoarthritis Index) and SF-36 (Medical Outcomes Study Short Form Health Survey) scores. RESULTS: The intra-articular injections produced a significant reduction in weight-bearing pain, resting pain, maximum pain and Lequesne and WOMAC scores after 26 weeks. There were no significant differences in outcome between any of the three study groups during the first 26 weeks. In direct comparison against placebo for weeks 0-52, neither hyaluronan treatment (Artzal or Synvisc) showed a significantly longer duration of clinical benefit than placebo. However, when data for the two hyaluronan-treated groups were pooled, treatment with hyaluronan had a significantly longer duration of benefit compared with placebo (P = 0.047). CONCLUSION: Patients with knee osteoarthritis who were treated by injection into the knee of either of two hyaluronan preparations or placebo showed clinical improvement during the first 26 weeks of treatment, though neither hyaluronan preparation gave a longer duration of clinical benefit than placebo. However, when data for the two hyaluronan treatments were pooled, there was a significantly longer duration of clinical benefit for hyaluronan treatment than for placebo.

The potential of telemedicine: barriers, incentives and possibilities in the implementation phase.

Between 1998 and 1999, the Swedish Institute for Health Services Development (Spri) evaluated three applications in which specialist competence was being accessed via telemedicine. The results indicated that these kinds of application can be cost-effective in an organization well adapted to new technology and that telemedicine can improve continuity of care for patients. However, the new technology was seldom supported by the old organization and better education and technical support are needed. In a study called 'Incentives and Implementation', the Federation of Swedish County Councils interviewed people in Swedish health-care with a lot of experience of telemedicine. The interviewees agreed that telemedicine was likely to affect the whole structure of health-care. Peripheral competence was expected to increase and referral patterns to change, as well as the functions of the personnel and the hospitals. New working conditions and methods of work were expected to be made possible by telemedicine and health-care was expected to become more process oriented, partly because patients are likely to be more demanding and better informed. To be able to utilize this potential, health-care managers will have to show more interest in and commitment to telemedicine. Old organizational patterns must be called into question and be developed along with information technology and telemedicine. It is also important to give priority to training in telemedicine for physicians and nurses.

Temporal regulation of endothelial ET-1 and eNOS expression in intact human conduit vessels exposed to different intraluminal pressure levels at physiological shear stress.

OBJECTIVE: By using a computerized vascular perfusion model, we investigated temporal effects of sub-acute pressure elevation on vasomotor behavior and expression of endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) in intact human conduit vessels. METHODS: Paired umbilical veins were perfused during 1.5, 3 and 6 h under high/low intraluminal pressure (40/20 mmHg) and at identical shear stress level of 10 dyn/cm(2). ET-1 and eNOS gene and protein expression was quantified with real-time reverse-transcribed polymerase chain reaction and quantitative immunohistochemistry, respectively. RESULTS: Pressure induced differential temporal regulation patterns of ET-1 and eNOS gene expression. During the high pressure condition, eNOS mRNA was upregulated after 3 h and leveled off after 6 h of perfusion, while ET-1 mRNA was elevated after 6 h perfusion. Immunohistochemistry verified synchronal changes at the protein level. Significant vasodilation was observed after 3 h in the high-pressure system. CONCLUSION: Thus, subacute pressure elevation exerts differential effects on the endothelial eNOS/ET-1 expression, which dynamically regulate the vasomotor tone.

Fluid shear stress increases the intra-cellular storage pool of tissue-type plasminogen activator in intact human conduit vessels.

We investigated the effect of shear stress on the expression of tissue-type plasminogen activator (t-PA) in intact human conduit vessels. Human umbilical veins were exposed to high or low shear stress (25 vs < 4 dyn/cm2) at identical intraluminal pressure (20 mmHg) for 1.5, 3, and 6 h in a new computerized biomechanical perfusion system. High shear perfusion induced a marked, time-dependent increase in t-PA immunostaining in both the endothelium and the media. t-PA relative to GAPDH gene expression increased by 54 +/- 14% in high- compared to low-sheared vessels (p = 0.002). By contrast, t-PA release into the perfusion medium was similar in vessels perfused under high or low shear stress conditions. The results show that shear stress independently of pressure is a potent fluid mechanical stimulus for up-regulation of the intracellular storage pool of t-PA in the vascular wall of fresh human conduit vessels. The shear effect is associated with an increased t-PA gene expression.

Differential immediate-early gene responses to shear stress and intraluminal pressure in intact human conduit vessels.

We have previously shown distinct effects of shear stress and pressure on transcription of several potent vascular mediators. In the present study, we tested the hypothesis that c-jun and c-fos are regulated differentially by shear and pressure. Intact human umbilical veins were perfused with various combinations of shear and pressure during 1.5, 3 and 6 h. Protein and gene expressions were assessed by immunofluorescence and real-time reverse transcription PCR, respectively. Shear stress and pressure exert differential temporal effects on c-jun and c-fos gene and protein expression, and these immediate-early gene responses appear to be cell-type specific for endothelial and smooth muscle cells.

Optimizing the therapeutic approach of transurethral alprostadil.

OBJECTIVE: To investigate the efficacy and safety of two different starting doses of transurethral alprostadil (250 microg and 500 microg, MUSE, Vivus Inc., Menlo Park, CA, USA, and Astra Läkemedel AB, Södertälje, Sweden) and the need for dose titration in a general population with erectile dysfunction. PATIENTS AND METHODS: In a 12-week randomized and open multicentre study with parallel groups, 166 patients were randomised to a starting dose of either 250 or 500 microg of MUSE and evaluated for safety. Of these patients, 142 were included in the analysis of efficacy. MUSE marked in four doses (125, 250, 500 and 1000 microg) was supplied and during the trial the dose could be increased or decreased step-wise until a satisfactory response was attained. The efficacy was assessed using the Erection Assessment Scale (EAS), as coitus (by diary) and the International Index of Erectile Function. RESULTS: The lowest dose of MUSE with which the patients achieved at least one EAS score of 4 or 5 was 125 microg for 1% of participants, 250 ++microg for 27%, 500 microg for 32%, 1000 microg for 6%, and finally 1000 microg plus a pubic band for 8%. Thirty-five of the 142 patients (25%) did not report an EAS of 4 or 5. Most patients (> 60%) achieved an EAS of 4 or 5 on the lower doses (125, 250 and 500 microg). Almost all patients who had an EAS score of 4 or 5 also had intercourse. In all, 68% reported sexual intercourse at least once in course of the study. More patients reported penile pain while treated with 500 microg than with 250 microg (P < 0.05) during the first 4 weeks. However, the penile pain was severe in very few men and it was a minor problem. Hypotensive symptoms were reported six times, independently of dose level. The administration of MUSE was generally rated as comfortable. No patients reported urethral stricture, penile fibrosis, or priapism either in the clinic or at home. CONCLUSION: Recommending 500 microg as a starting dose increased the percentage of patients reporting at least one EAS of 4-5, with or without sexual intercourse, from 28% to 60%. No serious dose-related systemic effects were seen. When starting on 500 microg, patients were more likely to find directly the dose that gave sufficient response and treatment satisfaction. We suggest that the appropriate starting dose of MUSE should be 500 microg.

Distinct regulation of vascular endothelial growth factor in intact human conduit vessels exposed to laminar fluid shear stress and pressure.

VEGF is a potent angiogenic factor. We tested the hypothesis that biomechanical forces may regulate VEGF expression. By using a computerized perfusion system, human umbilical veins were exposed to high/low shear stress or intraluminal pressure (25/4 dyn/cm(2) or 40/20 mmHg) for 1.5, 3, or 6 h. Quantification of VEGF gene expression was performed with real-time RT-PCR. VEGF protein was characterized by quantitative immunohistochemistry. All perfusion experiments were performed under identical pH, PO(2), and temperature. Shear stress induced significant biphasic regulation pattern of VEGF (P = 0.0044) with significant downregulation by 45 and 40% after 1.5 and 6 h perfusion, respectively (P = 0.006 and P = 0.0002). The temporal changes of the gene expression were accompanied by synchronal changes at the protein level. High pressure induced transient 25% downregulation of VEGF gene expression after 1.5 h perfusion (P = 0.031). These data provide the first evidence on modulating effects of biomechanical forces on the vascular angiogenic property.

Elevated intraluminal pressure inhibits vascular tissue plasminogen activator secretion and downregulates its gene expression.

We recently discovered that patients with essential hypertension have a markedly impaired capacity for stimulated release of tissue plasminogen activator (tPA) from vascular endothelium. This defect may reduce the chance of timely spontaneous thrombolysis in case of an atherothrombotic event. We now investigated whether increased intraluminal pressure as such may depress vascular tPA release or downregulate its gene expression. Segments of human umbilical veins were studied in a new computerized vascular perfusion model under steady laminar flow conditions for 3 or 6 hours. Paired segments were perfused at high or physiological intraluminal pressure (40 versus 20 mm Hg) under identical shear stress (10 dyne/cm(2)). Quantitative immunohistochemical evaluation of cellular tPA immunoreactivity was performed on paraffin-embedded 5-microm vascular sections. tPA mRNA in endothelial cells was quantified with reverse transcription real-time TaqMan polymerase chain reaction with GAPDH as endogenous control. Secretion of tPA into perfusion medium was evaluated with SDS-PAGE and Western blotting, followed by densitometric quantification. High-pressure perfusion downregulated tPA gene expression with a 38% decrease in tPA mRNA levels (P=0.01) compared with vessels perfused under normal intraluminal pressure. tPA release into the perfusion medium was markedly suppressed by high pressure (P<0.01 ANOVA). The intracellular storage pool of tPA was reduced after 6 but not 3 hours. Thus, elevated intraluminal pressure downregulates tPA gene and protein expression and inhibits its release from the endothelium independently of shear stress. The defective capacity for stimulated tPA release that we demonstrated in patients with essential hypertension might thus be an effect of the elevated intraluminal pressure per se.

Effects of shear stress on eicosanoid gene expression and metabolite production in vascular endothelium as studied in a novel biomechanical perfusion model.

This study investigated the effects of shear stress on gene expression of prostacyclin synthesis-related enzymes cyclooxygenases (COX-1 and COX-2), prostacyclin synthase (PGS), and thromboxane synthase (TXS) and their metabolites prostaglandin (PGI(2)) and thromboxane A(2) (TXA(2)) in endothelium of intact conduit vessels. Paired human umbilical veins were perfused at high/low shear stress (25/<4 dyn/cm(2)) at identical intraluminal pressure (20 mmHg) for 1.5, 3, or 6 hours in a computerized vascular model. High shear perfusion induced a significant, monophasic upregulation of PGS and TXS gene expressions after 6 hours. COX-1 and COX-2 mRNA showed a biphasic response with peaks at 1.5 and 6 hours, with a nadir level at 3 hours. Shear-induced gene expression was associated with a significantly greater accumulation of 6-keto prostaglandin F(1alpha) and TXA(2) in the perfusion medium. Thus, shear stress independently of perfusion pressure alters the expression of prostacyclin synthesis-related enzymes and the biosynthesis of their vasoactive metabolites.

Telemedicine in Sweden--a diffusion study.

A survey of telemedicine use in Sweden was carried out. The response rate by hospital management was high at almost 90%. Sixty per cent of hospitals were involved in some kind of telemedicine activity in Sweden, with a further 15% planning telemedicine implementation. In rural areas of north Sweden good links exist between primary and secondary care. In the more populated southern region good links exist between the county hospitals and specialist university hospitals. Fifty-four per cent of telemedicine applications were used for specialist consultations, 13% for consultation between paramedics and hospitals and 10% for rounds. Teleradiology was the most frequent service.

A new computerized biomechanical perfusion model for ex vivo study of fluid mechanical forces in intact conduit vessels.

We have developed a new computerized biomechanical ex vivo perfusion system for intact conduit vessels in which a wide range of combinations of intraluminal pressure, fluid flow and shear stress could be set and maintained at target levels in mammalian conduit vessels under controlled metabolic conditions. Mean wall shear stress is calculated using the formula: Accuracy of the wall shear stress calculation was validated by ultrasonographic imaging of the vessel radius. In a series of simulation experiments, the hemodynamic homeostasis functions of the system were challenged by generating a wide range of vascular resistance in artificial vessels and by pharmacologically induced changes in vascular tone in intact human vessels. Despite rapid changes in vessel resistance, shear stress and pressure, or flow and pressure were maintained well at target levels. Shear- and pressure-stimulated production of the vasodilator prostaglandin E2 (PGE2) was used to validate the biological relevance of the model. PGE2 release was significantly more stimulated by high (25 dyn/cm2) compared to low (<4 dyn/cm2) shear (ANOVA, p = 0.012). High compared to low intraluminal pressure depressed the production of PGE2 (ANOVA, p = 0.019). In summary, the computerized perfusion model appears to offer new possibilities of investigating the complex interplay between fluid mechanics and the vascular wall.

Differences of bone alkaline phosphatase isoforms in metastatic bone disease and discrepant effects of clodronate on different skeletal sites indicated by the location of pain.

We compared clodronate with placebo administration in 42 primarily or secondarily hormone-refractory prostate cancer patients with skeletal metastases and persisting pain. Serum total alkaline phosphatase (ALP), bone ALP isoforms, osteocalcin, cross-linked carboxy-terminal telopeptide of type I collagen, and prostate-specific antigen were analyzed before and after 1 month of treatment. Six ALP isoforms were quantified by HPLC: one bone/intestinal, two bone (B1, B2), and three liver ALP isoforms. The most apparent difference compared with healthy males was observed for the bone ALP isoform B2. Patients and healthy males had a B2 activity corresponding to 75% and 35% of the total ALP activity, respectively (P <0.0001). We propose that the different bone ALP isoforms reflect different stages of osteoblast differentiation during the extracellular matrix maturation phase of osteogenesis. All bone markers except osteocalcin increased after 1 month of clodronate administration. These increases were associated with pain only in the upper part of the body. We suggest that the uptake of clodronate by the skeleton was not uniform during our treatment period.

Endothelium-dependent vasodilation and tissue-type plasminogen activator release in borderline hypertension.

We recently showed that muscarinic receptor stimulation causes a marked increase in the net release of tissue-type plasminogen activator (TPA) antigen and activity across the human forearm in vivo, in conjunction with endothelium-dependent vasodilation. Because hypertension has been associated with endothelial dysfunction, the aim of the study was to compare forearm TPA release and vasodilation in response to muscarinic stimulation in normotensive (NC) and borderline hypertensive (BH) subjects. The study was performed in 10 apparently healthy young men with BH and 10 male NC subjects. Methacholine (MCh: 0.1, 0.8, and 4.0 micrograms/min) and sodium mitroprusside (SNP: 0.5, 2.5, and 10 micrograms/min) were administered in randomized order as double-blind, stepwise, intrabrachial artery infusions. Forearm blood flow was assessed by plethysmography. Net release/uptake was calculated as the product of the arteriovenous concentration gradient and forearm plasma flow. Vasodilator responses to MCh were similar in both groups (P = NS), whereas the decrease in forearm vascular resistance in response to SNP was somewhat less in BH subjects (P = .005). At rest, both groups showed a significant arteriovenous gradient and net release of TPA antigen across the forearm (P < .05 throughout). However, in contrast to the significant net increment in TPA activity across the forearm in the NC group (P < .018), BH subjects had no basal forearm increment in TPA activity (NC vs BH, P = .006). Arterial and venous plasma levels of plasminogen activator inhibitor 1 (PAI-1) antigen and activity were higher in BH subjects (P < or = .05 throughout), who in contrast to NC subjects, also had a significant forearm net release of PAI-1 antigen (P = .006). Across the whole group, there was a significant inverse relation between arterial PAI-1 antigen levels and increment in TPA activity across the forearm (r = -.57, P = .008) but no relation to TPA antigen release. In response to MCh infusion, both the net release of TPA antigen and increment in TPA activity increased markedly and to similar extents in both groups (P < .01 throughout). SNP infusion had no effect on either TPA antigen release or increment in TPA activity in the NC group but elicited a significant net release of TPA antigen and increase in TPA activity in the BH group (P < .05). Both circulating levels and local release of PAI-1 antigen were significantly correlated to fasting plasma insulin. Endothelium-dependent vasodilation and endothelial TPA release in response to muscarinic receptor stimulation were preserved in BH subjects. At rest, BH subjects had higher circulating PAI-1 antigen levels and a corresponding decrease in circulating levels and local increment of TPA activity. In contrast to NC subjects, BH subjects responded with a TPA release also in response to increased flow, which may indicate an enhanced endothelial cell responsiveness to fluid shear stress.