Effect of long-term testosterone therapy on molecular regulators of skeletal muscle mass and fibre-type distribution in aging men with subnormal testosterone

BACKGROUND

Long-term testosterone replacement therapy (TRT) increases muscle mass in elderly men with subnormal testosterone levels. However, the molecular mechanisms underlying this effect of TRT on protein balance in human skeletal muscle in vivo remain to be established.

METHODS

Here, we examined skeletal muscle biopsies obtained before and 24-h after the last dose of treatment with either testosterone gel (n = 12) or placebo (n = 13) for 6 months in aging men with subnormal bioavailable testosterone levels. The placebo-controlled, testosterone-induced changes (β-coefficients) in mRNA levels, protein expression and phosphorylation were examined by quantitative real-time PCR and western blotting.

RESULTS

Long-term TRT increased muscle mass by β = 1.6 kg (p = 0.01) but had no significant effect on mRNA levels of genes involved in myostatin/activin/SMAD or IGF1/FOXO3 signalling, muscle-specific E3-ubiquitin ligases, upstream transcription factors (MEF2C, PPARGC1A-4) or myogenic factors. However, TRT caused a sustained decrease in protein expression of SMAD2 (β = -36%, p = 0.004) and SMAD3 (β = -32%, p = 0.001), which was accompanied by reduced protein expression of the muscle-specific E3-ubiquitin ligases, MuRF1 (β = -26%, p = 0.004) and Atrogin-1/MAFbx (β = -20%, p = 0.04), but with no changes in FOXO3 signalling. Importantly, TRT did not affect muscle fibre type distribution between slow-oxidative (type 1), fast-oxidative (type 2a) and fast-glycolytic (type 2×) muscle fibres.

CONCLUSIONS

Our results indicate that long-term TRT of elderly men with subnormal testosterone levels increases muscle mass, at least in part, by decreasing protein breakdown through the ubiquitin proteasome pathway mediated by a sustained suppression of SMAD-signalling and muscle-specific E3-ubiquitin ligases.

Mitochondria, glycogen, and lipid droplets in skeletal muscle during testosterone treatment and strength training: a randomized, double-blinded, placebo-controlled trial

Low testosterone levels in aging men are associated with insulin resistance. Mitochondrial dysfunction, changes in glycogen metabolism, and lipid accumulation are linked to insulin resistance in skeletal muscle. In this randomized, double-blinded, placebo-controlled study, we investigated the effects of six-month testosterone replacement therapy (TRT) and strength training (ST) on mitochondrial, glycogen, and lipid droplet (LD) content in skeletal muscle of aging men with subnormal bioavailable testosterone (BioT) levels. Mitochondrial, glycogen, and LD volume fractions in muscle biopsies were estimated by transmission electron microscopy. Insulin sensitivity (insulin-stimulated Rd) and body composition were assessed by euglycemic-hyperinsulinemic clamp and dual X-ray absorptiometry, respectively. TRT significantly increased total testosterone levels, BioT, and lean body mass (LBM) (p < 0.05), whereas percent body fat decreased (p < 0.05), and insulin sensitivity was unchanged. Baseline mitochondrial volume fraction correlated inversely with percent body fat (ρ = -0.43; p = 0.003). Δ-mitochondrial fraction correlated positively with Δ-total testosterone (ρ = 0.70; p = 0.02), and Δ-glycogen fraction correlated inversely with Δ-LBM (ρ = -0.83; p = 0.002) during six-month TRT, but no significant changes were observed in mitochondrial, glycogen, and LD volume fractions during TRT and ST. In conclusion, in this exploratory small-scale study, the beneficial effects of six-month TRT on total testosterone, LBM, and percent body fat were not followed by significant changes in fractions of mitochondria, glycogen, or lipid in skeletal muscle of aging men with lowered testosterone levels. Six-month ST or combined three-month ST+TRT did not change intramyocellular mitochondria, glycogen, and LD fractions compared to placebo. However, further studies with a larger sample size are needed.

Marker-dependent associations among oxidative stress, growth and survival during early life in a wild mammal

Oxidative stress (OS) is hypothesized to be a key physiological mechanism mediating life-history trade-offs, but evidence from wild populations experiencing natural environmental variation is limited. We tested the hypotheses that increased early life growth rate increases OS, and that increased OS reduces first-winter survival, in wild Soay sheep (Ovis aries) lambs. We measured growth rate and first-winter survival for four consecutive cohorts, and measured two markers of oxidative damage (malondialdehyde (MDA), protein carbonyls (PC)) and two markers of antioxidant (AOX) protection (total AOX capacity (TAC), superoxide dismutase (SOD)) from blood samples. Faster lamb growth was weakly associated with increased MDA, but not associated with variation in the other three markers. Lambs with higher SOD activity were more likely to survive their first winter, as were male but not female lambs with lower PC concentrations. Survival did not vary with MDA or total TAC. Key predictions relating OS to growth and survival were therefore supported in some OS markers, but not others. This suggests that different markers capture different aspects of the complex relationships between individual oxidative state, physiology and fitness, and that overarching hypotheses relating OS to life-history variation cannot be supported or refuted by studying individual markers.

Reduction of calprotectin and phosphate during testosterone therapy in aging men: a randomized controlled trial

OBJECTIVES

To investigate the effect of testosterone treatment on biomarkers calprotectin, fibroblast growth factor 23 (FGF23), soluble Klotho, phosphate, calcium, parathyroid hormone, creatinine and estimated glomerular filtration rate.

DESIGN

Randomized, double-blinded, placebo-controlled study.

SETTING

Odense Androgen Study-the effect of Testim and training in hypogonadal men.

PARTICIPANTS

Men aged 60-78 years old with a low normal concentration of free of bioavailable testosterone <7.3 nmol/L and waist circumference >94 cm recruited from 2008 to 2009 (N = 48) by advertisement.

INTERVENTION

Participants were randomized to receive 5-10 g gel/50-100 mg testosterone (Testim^®, Ipsen, France) or 5-10 g gel/placebo.

RESULTS

The plasma levels of calprotectin and phosphate were significantly reduced in the group receiving testosterone therapy (gel) compared to the placebo group (p < 0.05). Testosterone treatment did not have any significant effect on plasma levels of FGF23 or soluble Klotho. The reduction in phosphate levels was inversely associated with bioavailable testosterone.

CONCLUSION

Compared to the placebo group, 6 months of testosterone therapy (gel) reduced calprotectin and phosphate levels suggesting decreased inflammation and decreased cardiovascular risk.

Oxidative stress and life histories: unresolved issues and current needs

Life‐history theory concerns the trade‐offs that mold the patterns of investment by animals between reproduction, growth, and survival. It is widely recognized that physiology plays a role in the mediation of life‐history trade‐offs, but the details remain obscure. As life‐history theory concerns aspects of investment in the soma that influence survival, understanding the physiological basis of life histories is related, but not identical, to understanding the process of aging. One idea from the field of aging that has gained considerable traction in the area of life histories is that life‐history trade‐offs may be mediated by free radical production and oxidative stress. We outline here developments in this field and summarize a number of important unresolved issues that may guide future research efforts. The issues are as follows. First, different tissues and macromolecular targets of oxidative stress respond differently during reproduction. The functional significance of these changes, however, remains uncertain. Consequently there is a need for studies that link oxidative stress measurements to functional outcomes, such as survival. Second, measurements of oxidative stress are often highly invasive or terminal. Terminal studies of oxidative stress in wild animals, where detailed life‐history information is available, cannot generally be performed without compromising the aims of the studies that generated the life‐history data. There is a need therefore for novel non‐invasive measurements of multi‐tissue oxidative stress. Third, laboratory studies provide unrivaled opportunities for experimental manipulation but may fail to expose the physiology underpinning life‐history effects, because of the benign laboratory environment. Fourth, the idea that oxidative stress might underlie life‐history trade‐offs does not make specific enough predictions that are amenable to testing. Moreover, there is a paucity of good alternative theoretical models on which contrasting predictions might be based. Fifth, there is an enormous diversity of life‐history variation to test the idea that oxidative stress may be a key mediator. So far we have only scratched the surface. Broadening the scope may reveal new strategies linked to the processes of oxidative damage and repair. Finally, understanding the trade‐offs in life histories and understanding the process of aging are related but not identical questions. Scientists inhabiting these two spheres of activity seldom collide, yet they have much to learn from each other.

Plasma markers of oxidative stress are uncorrelated in a wild mammal

Oxidative stress, which results from an imbalance between the production of potentially damaging reactive oxygen species versus antioxidant defenses and repair mechanisms, has been proposed as an important mediator of life‐history trade‐offs. A plethora of biomarkers associated with oxidative stress exist, but few ecological studies have examined the relationships among different markers in organisms experiencing natural conditions or tested whether those relationships are stable across different environments and demographic groups. It is therefore not clear to what extent studies of different markers can be compared, or whether studies that focus on a single marker can draw general conclusions regarding oxidative stress. We measured widely used markers of oxidative damage (protein carbonyls and malondialdehyde) and antioxidant defense (superoxide dismutase and total antioxidant capacity) from 706 plasma samples collected over a 4‐year period in a wild population of Soay sheep on St Kilda. We quantified the correlation structure among these four markers across the entire sample set and also within separate years, age groups (lambs and adults), and sexes. We found some moderately strong correlations between some pairs of markers when data from all 4 years were pooled. However, these correlations were caused by considerable among‐year variation in mean marker values; correlation coefficients were small and not significantly different from zero after accounting for among‐year variation. Furthermore, within each year, age, and sex subgroup, the pairwise correlation coefficients among the four markers were weak, nonsignificant, and distributed around zero. In addition, principal component analysis confirmed that the four markers represented four independent axes of variation. Our results suggest that plasma markers of oxidative stress may vary dramatically among years, presumably due to environmental conditions, and that this variation can induce population‐level correlations among markers even in the absence of any correlations within contemporaneous subgroups. The absence of any consistent correlations within years or demographic subgroups implies that care must be taken when generalizing from observed relationships with oxidative stress markers, as each marker may reflect different and potentially uncoupled biochemical processes.

Differential effects of strength training and testosterone treatment on soluble CD36 in aging men: Possible relation to changes in body composition

PURPOSE

We measured soluble CD36 (sCD36) and body composition to determine the effects of testosterone treatment (TT) and/or strength training (ST) on cardiovascular risk in men with low normal testosterone levels.

METHODS

Double-blinded, placebo-controlled study in 54 men aged 60-78 years with bioavailable testosterone < 7.3 nmol/L and waist > 94 cm randomized to TT (gel, 50-100 mg/day, n = 20), placebo (n = 18) or ST (n = 16) for 6 months. Moreover, the ST group was randomized to TT (ST + TT, n = 7) or placebo (ST + placebo, n = 9) after 3 months.

OUTCOMES

sCD36, total and regional fat mass were established by Dual X-ray absorptiometry and magnetic resonance imaging. Data are presented as median (quartiles). Kruskal-Wallis and Mann-Whitney tests were performed on delta values at 0, 3 and 6 months.

RESULTS

ST + placebo decreased sCD36 levels by 21% [from 0.80 (0.68-1.22) to 0.63 (0.51-0.73) rel. units] vs. TT and vs. placebo (p < 0.05). ST + placebo did not change bioavailable testosterone and lean body mass. Fat mass measures significantly improved during ST + placebo, ST + TT, and TT vs. placebo. During ST + placebo, delta sCD36 was associated with delta total fat mass (r = 0.81) and delta central fat mass (r = 0.84).

CONCLUSIONS

Compared to testosterone treatment, six months of strength training reduced sCD36 levels suggesting decreased cardiovascular risk, possibly due to a reduction in central fat mass.

Effect of testosterone on markers of mitochondrial oxidative phosphorylation and lipid metabolism in muscle of aging men with subnormal bioavailable testosterone

OBJECTIVE

Recent studies have indicated that serum testosterone in aging men is associated with insulin sensitivity and expression of genes involved in oxidative phosphorylation (OxPhos), and that testosterone treatment increases lipid oxidation. Herein, we investigated the effect of testosterone therapy on regulators of mitochondrial biogenesis and markers of OxPhos and lipid metabolism in the skeletal muscle of aging men with subnormal bioavailable testosterone levels.

METHODS

Skeletal muscle biopsies were obtained before and after treatment with either testosterone gel (n=12) or placebo (n=13) for 6 months. Insulin sensitivity and substrate oxidation were assessed by euglycemic-hyperinsulinemic clamp and indirect calorimetry. Muscle mRNA levels and protein abundance and phosphorylation of enzymes involved in mitochondrial biogenesis, OxPhos, and lipid metabolism were examined by quantitative real-time PCR and western blotting.

RESULTS

Despite an increase in lipid oxidation (P<0.05), testosterone therapy had no effect on insulin sensitivity or mRNA levels of genes involved in mitochondrial biogenesis (PPARGC1A, PRKAA2, and PRKAG3), OxPhos (NDUFS1, ETFA, SDHA, UQCRC1, and COX5B), or lipid metabolism (ACADVL, CD36, CPT1B, HADH, and PDK4). Consistently, protein abundance of OxPhos subunits encoded by both nuclear (SDHA and UQCRC1) and mitochondrial DNA (ND6) and protein abundance and phosphorylation of AMP-activated protein kinase and p38 MAPK were unaffected by testosterone therapy.

CONCLUSION

The beneficial effect of testosterone treatment on lipid oxidation is not explained by increased abundance or phosphorylation-dependent activity of enzymes known to regulate mitochondrial biogenesis or markers of OxPhos and lipid metabolism in the skeletal muscle of aging men with subnormal bioavailable testosterone levels.

Dysregulation of the transcription factors SOX4, CBFB and SMARCC1 correlates with outcome of colorectal cancer

The aim of this study was to identify deregulated transcription factors (TFs) in colorectal cancer (CRC) and to evaluate their relation with the recurrence of stage II CRC and overall survival. Microarray-based transcript profiles of 20 normal mucosas and 424 CRC samples were used to identify 51 TFs displaying differential transcript levels between normal mucosa and CRC. For a subset of these we provide in vitro evidence that deregulation of the Wnt signalling pathway can lead to the alterations observed in tissues. Furthermore, in two independent cohorts of microsatellite-stable stage II cancers we found that high SOX4 transcript levels correlated with recurrence (HR 2.7; 95% CI, 1.2–6.0; P=0.01). Analyses of ∼1000 stage I–III adenocarcinomas, by immunohistochemistry, revealed that patients with tumours displaying high levels of CBFB and SMARCC1 proteins had a significantly better overall survival rate (P=0.0001 and P=0.0275, respectively) than patients with low levels. Multivariate analyses revealed that a high CBFB protein level was an independent predictor of survival. In conclusion, several of the identified TFs seem to be involved in the progression of CRC.

Determinants of discard of expanded criteria donor kidneys: impact of biopsy and machine perfusion

We examined factors associated with expanded criteria donor (ECD) kidney discard. Scientific Registry of Transplant Recipients (SRTR)/Organ Procurement and Transplantation Network (OPTN) data were examined for donor factors using logistic regression to determine the adjusted odds ratio (AOR) of discard of kidneys recovered between October 1999 and June 2005. Logistic and Cox regression models were used to determine associations with delayed graft function (DGF) and graft failure. Of the 12,536 recovered ECD kidneys, 5139 (41%) were discarded. Both the performance of a biopsy (AOR = 1.21, p = 0.02) and the degree of glomerulosclerosis (GS) on biopsy were significantly associated with increased odds of discard. GS was not consistently associated with DGF or graft failure. The discard rate of pumped ECD kidneys was 29.7% versus 43.6% for unpumped (AOR = 0.52, p < 0.0001). Among pumped kidneys, those with resistances of 0.26-0.38 and >0.38 mmHg/mL/min were discarded more than those with resistances of 0.18-0.25 mmHg/mL/min (AOR = 2.5 and 7.9, respectively). Among ECD kidneys, pumped kidneys were less likely to have DGF (AOR = 0.59, p < 0.0001) but not graft failure (RR = 0.9, p = 0.27). Biopsy findings and machine perfusion are important correlates of ECD kidney discard; corresponding associations with graft failure require further study.

Kidney and pancreas transplantation in the United States, 1997-2006: the HRSA Breakthrough Collaboratives and the 58 DSA Challenge

Growth in the number of active patients on the kidney transplant waiting list has slowed. Projections based on the most recent 5-year data suggest the total waiting list will grow at a rate of 4138 registrations per year, whereas the active waiting list will increase at less than one-sixth that rate, or 663 registrations per year. The last 5 years have seen a small trend toward improved unadjusted allograft survival for living and deceased donor kidneys. Since 2004 the overall number of pancreas transplants has declined. Among pancreas recipients, those with simultaneous kidney-pancreas transplants experienced the highest pancreas graft survival rates. In response to the ongoing shortage of deceased donor organs, the US Health Resources and Services Administration launched the Organ Donation Breakthrough Collaborative in September 2003 and the Organ Transplantation Breakthrough Collaborative (OTBC) in October 2005. The 58 DSA Challenge is prominent among the goals adopted by the OTBC. Its premise: were each of the 58 existing donation service areas to increase the number of kidney transplants performed within their boundaries by 10 per month, an additional 7000 transplants over current annual levels would result. Such an increase could potentially eliminate the national kidney transplantation waiting list by 2030.

Pediatric transplantation in the United States, 1996-2005

Solid organ transplantation is accepted as a standard lifesaving therapy for end-stage organ failure in children. This article reviews trends in pediatric transplantation from 1996 to 2005 using OPTN data analyzed by the Scientific Registry of Transplant Recipients. Over this period, children have contributed significantly to the donor pool, and although the number of pediatric donors has fallen from 1062 to 900, this still accounts for 12% of all deceased donors. In 2005, 2% of 89,884 candidates listed for transplantation were less than 18 years old; in 2005, 1955 children, or 7% of 28,105 recipients, received a transplant. Improvement in waiting list mortality is documented for most organs, but pretransplant mortality, especially among the youngest children, remains a concern. Posttransplant survival for both patients and allografts similarly has shown improvement throughout the period; in most cases, survival is as good as or better than that seen in adults. Examination of immunosuppressive practices shows an increasing tendency across organs toward tacrolimus-based regimens. In addition, use of induction immunotherapy in the form of anti-lymphocyte antibody preparations, especially the interleukin-2 receptor antagonists, has increased steadily. Despite documented advances in care and outcomes for children undergoing transplantation, several considerations remain that require attention as we attempt to optimize transplant management.

Kidney and pancreas transplantation in the United States, 1995-2004

This article examines OPTN/SRTR data on kidney and pancreas transplantation for 2004 and the previous decade, and discusses recent changes in kidney-pancreas (KP) allocation policy and emerging issues in kidney donation after cardiac death (DCD). Although the number of kidney donors continues to increase, new waiting list registrations again outpaced the number of kidney transplants performed, rising by 11% between 2003 and 2004 and contributing to a 1-year increase of 8% in the number of patients active on the waiting list. DCD has increased steadily since 2000; 39% more DCD transplants were performed in 2004 than 2003. Both deceased donor and living donor kidney graft survival rates remain excellent and are improving. The number of people living with a functioning kidney transplant doubled between 1995 and 2004, to 101,440 with a functioning kidney-alone and 7213 with a functioning KP. Health care providers in all settings are more likely to be exposed to these transplant recipients. Patient survival following simultaneous pancreas-kidney (SPK) transplantation is excellent and has improved incrementally since 1995; death rates in the first year fell from 60 per 1000 patient-years at risk in 2001 to 45 in 2003. The number of solitary pancreas transplants increased dramatically in 2004.

Gene expression signatures for colorectal cancer microsatellite status and HNPCC

The majority of microsatellite instable (MSI) colorectal cancers are sporadic, but a subset belongs to the syndrome hereditary nonpolyposis colorectal cancer (HNPCC). Microsatellite instability is caused by dysfunction of the mismatch repair (MMR) system that leads to a mutator phenotype, and MSI is correlated to prognosis and response to chemotherapy. Gene expression signatures as predictive markers are being developed for many cancers, and the identification of a signature for MMR deficiency would be of interest both clinically and biologically. To address this issue, we profiled the gene expression of 101 stage II and III colorectal cancers (34 MSI, 67 microsatellite stable (MSS)) using high-density oligonucleotide microarrays. From these data, we constructed a nine-gene signature capable of separating the mismatch repair proficient and deficient tumours. Subsequently, we demonstrated the robustness of the signature by transferring it to a real-time RT-PCR platform. Using this platform, the signature was validated on an independent test set consisting of 47 tumours (10 MSI, 37 MSS), of which 45 were correctly classified. In a second step, we constructed a signature capable of separating MMR-deficient tumours into sporadic MSI and HNPCC cases, and validated this by a mathematical cross-validation approach. The demonstration that this two-step classification approach can identify MSI as well as HNPCC cases merits further gene expression studies to identify prognostic signatures.

Marriage and family therapists evaluate managed mental health care: a qualitative inquiry

This study examined the experiences of 26 marriage and family therapists working in managed mental health care. A qualitative strategy was used to explore therapists' perspectives regarding practice in a managed care environment. Using an open-ended, semi-structured, mailed questionnaire four themes emerged from the data. These are the adaptations of clinical practice, issues of treatment duration/abandonment, effects of managed care on the therapeutic relationship, and issues of diagnosis. Recommendations are drawn from the findings and discussed.

Glycosylation of the N-terminal potential N-glycosylation sites in the human alpha1,3-fucosyltransferase V and -VI (hFucTV and -VI)

Human alpha1,3-fucosyltransferase V and -VI (hFucTV and -VI) each contain four potential N-glycosylation sites (hFucTV: Asn60, Asn105, Asn167 and Asn198 and hFucTVI: Asn46, Asn91, Asn153 and Asn184). Glycosylation of the two N-terminal potential N-glycosylation sites (hFucTV: Asn60, Asn105 and hFucTVI: Asn46 and Asn91) have never been studied in detail. In the present study, we have analysed the glycosylation of these potential N-glycosylation sites. Initially, we compared the molecular mass of hFucTV and -VI expressed in COS-7 cells treated with tunicamycin with the mass of the proteins in untreated cells. The difference in molecular mass between the proteins in treated and untreated cells corresponded to the presence of at least three N-linked glycans. We then made a series of mutants, in which the asparagine residues in the N-terminal potential N-glycosylation sites were replaced by glutamine. Western blotting analyses demonstrated that both sites in hFucTV were glycosylated, whereas in hFucTVI only one of the sites (Asn91) was glycosylated. All the single mutants and the hFucTVI N46Q/N91Q double mutant exhibited enzyme activities that did not differ considerably from the wt activities. However, the enzyme activity of the hFucTV N60Q/N105Q double mutant was reduced to approximately 40% of the wt activity. In addition, castanospermine treatment diminished the enzyme activity and hence trimming of the N-linked glycans are required for expression of full enzyme activity of both hFucTV and -VI. The present study demonstrates that both of the N-terminal potential N-glycosylation sites in hFucTV and one of the sites in hFucTVI are glycosylated. Individually, their glycosylation does not contribute considerably to expression of enzyme activity. However, elimination of both sites in hFucTV reduces the enzyme activity.

Specific binding of alpha-macroglobulin to complement-type repeat CR4 of the low-density lipoprotein receptor-related protein

The low-density lipoprotein receptor-related protein (LRP) is a large surface receptor that mediates binding and internalization of a large number of structurally and functionally unrelated ligands. The ligand binding sites are located in clusters of complement-type repeats (CR), where the general absence of mutual binding competition suggests that different ligands map to distinct sites. Binding of alpha(2)-macroglobulin-protease complexes to the LRP is mediated by the receptor binding domain (RBD) of alpha(2)-macroglobulin (alpha(2)M). To determine the major binding epitope(s) in the LRP, we generated a complete set of tandem CR proteins spanning the second cluster of CR domains, and identified a binding site for alpha(2)M in the N-terminal part of the cluster comprising CR3-CR6, using ligand blotting and surface plasmon resonance (SPR) analysis. The specific site involved in alpha(2)M recognition resides in the fourth CR domain, CR4, whereas another site is identified in CR5. An acidic epitope in CR4 is identified as important for binding alpha(2)M by mutagenesis and SPR analysis. The formation of the complex between the rat alpha(1)-macroglobulin RBD and CR domain pairs is characterized by analytical size-exclusion chromatography, which demonstrates a sufficiently strong interaction between the alpha(1)M RBD and CR34 or CR45 for the isolation of a complex.

The C-terminal N-glycosylation sites of the human alpha1,3/4-fucosyltransferase III, -V, and -VI (hFucTIII, -V, adn -VI) are necessary for the expression of full enzyme activity

The alpha1,3/4-fucosyltransferases are involved in the synthesis of fucosylated cell surface glycoconjugates. Human alpha1,3/4-fucosyltransferase III, -V, and -VI (hFucTIII, -V, and -VI) contain two conserved C-terminal N-glycosylation sites (hFucTIII: Asn154 and Asn185; hFucTV: Asn167 and Asn198; and hFucTVI: Asn153 and Asn184). In the present study, we have analyzed the functional role of these potential N-glycosylation sites, laying the main emphasis on the sites in hFucTIII. Tunicamycin treatment completely abolished hFucTIII enzyme activity while castanospermine treatment diminished hFucTIII enzyme activity to approximately 40% of the activity of the native enzyme. To further analyze the role of the conserved N-glycosylation sites in hFucTIII, -V, and -VI, we made a series of mutant genomic DNAs in which the asparagine residues in the potential C-terminal N-glycosylation sites were replaced by glutamine. Subsequently, the hFucTIII, -V, and -VI wild type and the mutants were expressed in COS-7 cells. All the mutants exhibited lower enzyme activity than the wild type and elimination of individual sites had different effects on the activity. The mutations did not affect the protein level of the mutants in the cells, but reduced the molecular mass as predicted. Kinetic analysis of hFucTIII revealed that lack of glycosylation at Asn185 did not change the Km values for the oligosaccharide acceptor and the nucleotide sugar donor. The present study demonstrates that hFucTIII, -V, and -VI require N-glycosylation at the two conserved C-terminal N-glycosylation sites for expression of full enzyme activity.

Alternative case definitions of ventilator-associated pneumonia identify different patients in a surgical intensive care unit

Diagnostic criteria that define ventilator-associated pneumonia (VAP) remain controversial. The purpose of this study was to evaluate common definitions of VAP and determine their relationship to each other and clinical treatment. This study prospectively evaluated several diagnostic criteria that define VAP in a cohort of 255 consecutive SICU patients ventilated for < 48 h. Definitions evaluated include the CDC definitions, the Johanson definitions which do not rely on culture data, the Physician's Probable diagnosis which relies on positive quantitative cultures, and the antibiotic treatment group. Forty-four patients (17%) received antibiotic treatment for VAP. Depending on the definition evaluated, criteria were met for a diagnosis of VAP from as low as 4% of patients by the Johanson definition to as high as 48% of patients by the CDC definition. There was poor agreement among the definitions in their ability to select the same patient as having VAP. Besides duration of mechanical ventilation and tube feeding, which were risk factors that predicted meeting the criteria for all groups, risk factors predicting VAP varied among the definitions. This study demonstrates that in a surgical ICU, the candidate definitions of pneumonia evaluated show little agreement. The particular case definition chosen to diagnose VAP will determine the incidence rate of pneumonia, the time to onset of pneumonia, and the risk factors of the type of patient treated.

Identification of the minimal functional unit in the low density lipoprotein receptor-related protein for binding the receptor-associated protein (RAP). A conserved acidic residue in the complement-type repeats is important for recognition of RAP

The low density lipoprotein receptor-related protein (LRP), a member of the low density lipoprotein receptor family, mediates the internalization of a diverse set of ligands. The ligand binding sites are located in different regions of clusters consisting of approximately 40 residues, cysteine-rich complement-type repeats (CRs). The 39-40-kDa receptor-associated protein, a folding chaperone/escort protein required for efficient transport of functional LRP to the cell surface, is an antagonist of all identified ligands. To analyze the multisite inhibition by RAP in ligand binding of LRP, we have used an Escherichia coli expression system to produce fragments of the entire second ligand binding cluster of LRP (CR3-10). By ligand affinity chromatography and surface plasmon resonance analysis, we show that RAP binds to all two-repeat modules except CR910. CR10 differs from other repeats in cluster II by not containing a surface-exposed conserved acidic residue between Cys(IV) and Cys(V). By site-directed mutagenesis and ligand competition analysis, we provide evidence for a crucial importance of this conserved residue for RAP binding. We provide experimental evidence showing that two adjacent complement-type repeats, both containing a conserved acidic residue, represent a minimal unit required for efficient binding to RAP.

Lewis antigen mediated adhesion of freshly removed human bladder tumors to E-selectin

PURPOSE

Twenty fresh surgical specimens of human bladder tumors were tested for their ability to adhere to recombinant P and E-selectin. The adhesion was correlated to immunological detection of carbohydrate structures.

MATERIALS AND METHODS

A static titertray assay with immobilized selectins and appropriate controls was used for bladder tumor cell adhesion. On the same tumors expression of carbohydrate structures was examined by immunohistochemistry and Western blotting.

RESULTS

No tumor bound to P-selectin. Nine tumors showed a high number of cells binding to E-selectin, 5 showed intermediate binding, and 6 showed only rare binding. The specificity of the binding was verified by inhibition with EDTA, by blocking antibodies to E-selectin, and by an acrylamide based sLe(x) (Galbeta1-4 [Fucalpha1-3]GlcNAc-) polymer. The binding was significantly more frequent (p <0.045) in superficial tumors than in invasive tumors. The binding property was correlated to the detection of carbohydrate structures in Western blots and tissue sections of the same tumors, using six different monoclonal antibodies: anti-sLe(a), anti-sLe(x), anti-Le(a), anti-Le(x) (two different clones) and anti-Le(b). Most blot-stainings were smeared indicating a mucin-type carrier molecule, but 115, 55 and 40 kDa bands carrying Le(a) and/or Le(b) epitopes were present in all tumors that bound. The Le(a) structure, as detected by blotting, was the only structure necessary for binding in the center of the wells (p <0.001), and was correlated to number of bound cells (p <0.006). A weaker correlation was found between Le(b) and number of bound cells (p <0.032), whereas it was remarkable that no correlation was found with Le(x) or sLe(x). Immunohistological staining of Le(a) on cell membranes correlated with frequent binding (p <0.003), whereas no correlation was found to secretor and Lewis genotypes.

CONCLUSIONS

These data on clinical specimens indicate that Lewis antigen mediated E-selectin adhesion may play a role in the human bladder cancer disease.

Indications of immunological tolerance in kidney transplantation

As a complication to immunosuppressive treatment in allotransplantation, malignant diseases such as post-transplant lymphoproliferative disorder (PTLD) may occur. The patient in the present case is a 21-year-old man transplanted at the age of 11 with a kidney from his mother and at the age of 15 with a kidney from his father. During the immunosuppressive treatment the patient developed PTLD resulting in the withdrawal of the immunosuppressive drugs. At the time of writing, the immunosuppressive drugs have been withdrawn for more than 3 years. We report the findings of a state of donor-specific tolerance occurring after transplantation. Post-transplant cells from the patient show a non-reactive response in mixed lymphocyte cultures (MLCs) to cells from both the mother and the father. We demonstrate a reduction in the mRNA expression of the Thl cytokines IL-2 and IFN-gamma in the very same MLCs. The expression of Th1 cytokine mRNA was measured semi-quantitatively using competitive reverse transcription-polymerase chain reaction (RT-PCR). The reduction in the Th1 cytokine mRNA expression is not seen in the MLCs with patient cells against cells from a paternal HLA-A, B and DR-matched individual, suggesting the influence of other allorecognition factors than HLA-A, B and DR. Detection in vitro of a lowered expression of Th1 cytokine mRNA supports the notion of these mRNAs as indicators of post-transplant tolerance. Further studies will reveal whether the cytokine mRNA measurements on short time stimulated lymphocytes can be used more generally as a monitoring parameter of tolerance in kidney transplantation.

The process of change in couples therapy: a qualitative investigation

Open-ended interviews with 24 couples therapy clients regarding their experience of the process of change revealed shifts in clusters of affect, communication, and cognition. Six additional contextual preconditions for change were also identified. The change process within couples was uniformly reported to be gradual.

Comparison of the level of cytokine mRNA in buffy coat-derived platelet concentrates prepared with or without white cell reduction by filtration

BACKGROUND

The generation of proinflammatory cytokines in platelet concentrates (PCs) by white cells is thought to be implicated in febrile nonhemolytic reactions. Furthermore, other cytokines could be generated in the PCs as signs of white cell activation when PCs are prepared from a pool of buffy coats (BCs). The number of white cells in the PCs is crucial to cytokine generation.

STUDY DESIGN AND METHODS

Each of the PCs (n = 12) was prepared from a pool of BCs from four donors. Before storage, half of the BC-derived PCs (BC-PCs) were white cell reduced by filtration. The BCs and the unfiltered and filtered BC-PCs were assayed for the presence of cytokine mRNA (i.e., interleukin [IL]-1beta, IL-6, tumor necrosis factor alpha [TNFalpha], IL-8, IL-2, and interferon gamma [IFN-gamma]) by the use of competitive reverse transcription-polymerase chain reaction.

RESULTS

No mRNA of cytokines with pyrogenic activity, that is, IL-1beta, IL-6 and TNFalpha, was detected in either the filtered or the unfiltered BC-PCs. Likewise, IL-2 mRNA was not found in any of the BC-PCs. IFN-gamma mRNA, however, was detected in the unfiltered BC-PCs but not in the filtered BC-PCs. IL-8 mRNA was found in both the unfiltered and the filtered BC-PCs, but with a lower frequency in the filtered BC-PCs.

CONCLUSION

The unfiltered BC-PCs produced in the top-and-bottom bag system contain traces or undetectable levels of the investigated cytokine mRNA. The results can be used in defining consensus recommendations for the use of filtered and unfiltered blood components.

Concentration measurement of unpurified proteins using biosensor technology under conditions of partial mass transport limitation

Using biosensor technology, it is possible to measure protein concentration when the binding of the protein to an appropriate ligand immobilized on the sensor surface is totally limited by diffusion and mass transport, a condition difficult to achieve in practice. In such a case, the observed binding rate does not reflect the intrinsic binding capacity of the molecular partners, but is simply proportional to the concentration of the protein analyte that is introduced in a continuous flow over the ligand. We describe here a more general biosensor method for measuring protein concentration which is applicable to conditions where mass transport is not totally but only partially rate limiting. The proposed method, which is based on measurements at different flow rates, does not require a standard of known protein concentration and can be used with unpurified proteins. The method is applicable to ligand-analyte pairs with an association rate constant as low as 10(3) M-1 s-1 and requires only knowledge of the molecular weight and diffusion coefficient of the analyte. The method was used successfully to measure the concentration of monoclonal antibodies, monoclonal antibody fragments (Fab) obtained by papain cleavage, and recombinant Fab fragments of widely different affinities in crude Escherichia coli extracts.

Theoretical analysis of protein concentration determination using biosensor technology under conditions of partial mass transport limitation

The theory of a method for determining active concentration of nonpurified protein samples using the BIAcore biosensor technology has been developed. The method relies on change in binding rate with varying flow rate at high ligand concentration where mass transport from bulk to surface with immobilized ligand becomes partially rate limiting. Prior study of binding kinetics is not necessary. If the molecular weight and the diffusion coefficient of the analyte protein are known, no standard with a known concentration is required. From numeric computer simulations a simple analytical expression for the mass transport coefficient derived at totally mass transport limiting conditions is shown to be applicable for conditions of partial mass transport limitation. Simple one to one association is assumed in deriving the method, but it is applicable even with more complex kinetics due to a bivalent analyte or heterogeneity of analyte or ligand.

Pressure-cross-sectional area relations and elasticity in the rabbit oesophagus in vivo

The aim was to assess the luminal cross-sectional area (CSA) and the passive elastic properties of the oesophageal body under luminal pressure loading in anaesthetized rabbits. Stepwise inflation of a luminal balloon, in which the CSA and pressure were measured by means of impedance planimetry and perfused low-compliance manometry, provided the distension stimulus. The parameters of elasticity were computed from steady state values of these measurements. The steady state pressure-CSA and pressure-radius relations were nonlinear. At the lowest and highest luminal pressure load of 1 and 10 kPa, the steady state CSAs were 39 +/- 3 and 91 +/- 4 mm2, respectively. The circumferential tension-strain distribution was nonlinear and showed an exponential behaviour that fitted well to the function tension = a.e(b.strain). Differentiation of the function yielded the wall stiffness which also showed an exponential behaviour.

Imaging of pelvic floor contractions using MRI

Magnetic resonance was used to visualize the effect of voluntary pelvic floor contractions on the abdominal structures with particular emphasis in determining the dynamic relationship between the bladder and surrounding organs. The pelvic floor was imaged in 6 asymptomatic female volunteers using MRI viewed in seven coronal and seven sagittal planes. The relative displacement of the bladder resulting from voluntary pelvic floor contraction was measured and the changes from the relaxed to the contracted stage were identified. Measurements from sagittal images show superior bladder wall movement of 3.8 +/- 1.3 mm, posterior of 7.0 +/- 2.8 mm, while maximum movement in the gluteal region was 3.5 +/- 4.0 mm. The results show that voluntary contractions of the pelvic floor measured and visualized using this technique can be identified and displayed using image processing techniques. Anatomical displacement of the bladder in the superior direction is illustrated, demonstrating that pelvic floor contraction provides increased levator muscle support. There is no significant displacement of the anterior aspect of the bladder, while the posterior wall demonstrates maximum movement.

Total transurethral resection versus minimal transurethral resection of the prostate--a 10-year follow-up study of urinary symptoms, uroflowmetry and residual volume

OBJECTIVE

To assess the long-term results of total transurethral resection (T-TURP) and minimal transurethral resection of the prostate (M-TURP) in patients with obstructive symptoms caused by benign prostatic hyperplasia.

PATIENTS AND METHODS

Between September 1979 and September 1980, 167 patients were studied: 83 were randomized to T-TURP and 84 to M-TURP. The patients were examined pre-operatively and 6 and 12 months post-operatively. Ten years post-operatively they were invited to attend for further examination, including uroflowmetry, determination of residual volume and evaluation of subjective symptoms.

RESULTS

At the 10-year follow-up 39 patients were found to have died and 47 were lost to follow-up. Twelve patients had undergone repeat TURP and seven had been treated for urethral stricture. Thus 33 T-TURP and 29 M-TURP patients underwent detailed examination. Significant relief in obstructive and irritative symptoms was seen in both groups. The improvement in maximum flow rate remained stable throughout the follow-up period, with no significant differences between the two groups. Post-void residual urine decreased throughout follow-up, with minor differences between the groups.

CONCLUSION

M-TURP is recommended as an alternative to T-TURP.

Fractionation sensitivity and latency of late radiation injury to the mouse urinary bladder

Transurethral bladder filling is a functional, non-invasive, in vivo assay of early and late radiation injury to the mouse bladder. Fractionated irradiations using single doses or 2, 3, 5, or 10 dose fractions in an overall time of 4 or 4.5 days, with a range of total doses, were given to the bladder of 12-14 week-old C3D2F1/Bom mice. In 372 mice, bladder volume at an intravesical pressure of 20 mmHg was measured before irradiation and at regular intervals thereafter. The endpoint for late bladder injury was a volume of less than 50% of the median pretreatment volume in all animals, occurring more than 30 days after irradiation. This endpoint was reached after a latent period ranging between 35 and 401 days. Fractionation and latency parameters were estimated using a mixture model. There was a highly statistically significant dose-dependency of the latent period (p < 10(-8)). The alpha/beta ratio was estimated at 5.8 Gy [95% confidence limits (3.6; 8.8) Gy] for 250 kVp X-rays. Thus late radiation injury in the mouse urinary bladder is one of the least sensitive late endpoints with respect to change in dose per fraction. Introducing early bladder injury as a variable in the model improved the fit significantly (p = 0.03), but the alpha/beta ratio remained unchanged. Thus the hypothesis that late bladder injury may be, at least in part, consequent upon early injury did not explain the relatively high alpha/beta ratio for this late endpoint.

Long-term observation of the detrusor smooth muscle in rats. Its relationship to ovariectomy and estrogen treatment

We studied the bladders of 24-month-old intact rats, rats that had been ovariectomized at the age of 6 months, and intact and ovariectomized rats treated by estrogen from the age of 16 months. The study thus comprized four groups: group I: bilaterally ovariectomized rats; group II: intact rats; group III: ovariectomized rats treated with estrogen; group IV: intact rats treated with estrogen. The weight and collagen concentration of the bladders were determined. The ovariectomized bladders weighed significantly less and had a higher collagen concentration than the intact bladders. Estrogen substitution for ovariectomized rats reversed these parameters. Detrusor strips were also used for organ bath studies. All bladders were similar in regard to the nerve-mediated frequency-response relationship. The atropine-resistant response was studied by adding scopolamine to the organ bath. Strips from ovariectomized rats had a significantly diminished atropine-resistant response, which was abolished by estrogen substitution. The present study suggests that micturition problems in menopause might have a structural as well as a pharmacological explanation.