My Baby, My Move+: feasibility of a community prenatal wellbeing intervention

BACKGROUND

Excessive gestational weight gain (EGWG), insufficient prenatal physical activity and sleep, and poor psychological wellbeing independently increase risks for adverse maternal and infant outcomes. A novel approach to mitigate these risks is utilizing peer support in a community-based prenatal intervention. This study assessed the feasibility (acceptability, demand, implementation, and practicality) of a remotely delivered prenatal physical activity intervention called My Baby, My Move + (MBMM +) that aims to increase prenatal physical activity, enhance mood and sleep hygiene, and reduce EGWG.

METHODS

Participants were recruited through community organizations, local clinics, and social media platforms in the Fall of 2020 and Spring of 2021. Eligible pregnant women were randomized to either the MBMM + intervention or the control group. Each group met over Zoom for 16 sessions (twice weekly for 60 min over 8 weeks) to learn either behavioral change and wellbeing knowledge and skills (MBMM +) or knowledge and skills related to parenting (control group). Multiple methods of evaluation to better understand the feasibility of the intervention were conducted.

RESULTS

A total of 49 women (25 MBMM + intervention, 24 control) completed both pre- and post-survey assessments and were included in the analyses. A subsample of 19 (39%) intervention participants completed a combination of semi-structured interviews/surveys to assess acceptability, demand, implementation, and practicality. Participants expressed positive feedback regarding acceptability (satisfaction and intent to continue use) and were extremely likely or likely to recommend the program to a friend (demand). Implementation metrics were assessed by observation and feedback forms completed by peer leaders and demonstrated high-quality control. Findings suggest that the intervention was practical due to remote sessions and cost-effectiveness.

CONCLUSION

The MBMM + intervention was deemed to be a feasible intervention with high acceptability, demand, implementation, and practicality. These findings can be used to inform the scalability of the intervention and implementation of a larger efficacy trial.

TRIAL REGISTRATION

19-1366, initial date is on January 23, 2020.

A Novel Solution to Better Understand the Link Between T Cell Metabolism and Function

In recent years, metabolism has emerged as a key driver of immune cell function in both healthy and disease settings. Indeed, it has been shown that metabolic reprogramming is a determinant of T cell phenotype and fate. Moreover, reprogramming of the metabolic pathways of T cells can be used as a strategy to improve the antitumor efficacy of adoptive T cell therapies. The Agilent Seahorse XF T cell Metabolic Profiling (XF TCMP) kit is a new solution that, combined with the Seahorse XF analyzer, allows for the simultaneous measurement of basal metabolic demand, metabolic poise and respiratory capacity in T cells. These parameters have been linked with optimal function and improved persistence of T cell therapies. The assay uses an improved uncoupler (BAM15) for more robust measurements of T cell bioenergetic capacity with less optimization than other uncouplers used. The XF TCMP kit was used to evaluate the metabolic phenotype of human T cells expanded in different nutrient conditions. T cells expanded in different cell culture media resulted in populations with different metabolic profiles. These metabolic profiles correlated with different functional markers, supporting the link between metabolism and function. The XF TCMP kit was also used to assess metabolic poise and bioenergetic capacity under nutrient-restriction, allowing us to better understand fuel requirements after expansion. Together, the data show that the XF TCMP kit provides a complete metabolic assessment of T cells in real-time. The assay can be used to develop improved anti-tumor T cell therapies by evaluating strategies that improve the persistence of infused cells or assess how T cells sustain metabolic fitness in nutrient restricted environments to maintain function.

Parents' Mental Health Experiences during the Perinatal Transition: A Qualitative Study

Capturing the voices of both parents regarding perinatal mental health is imperative. This qualitative study employed a purposive sampling technique to interview 23 individuals, including mothers, partners, and perinatal practitioners/educators. Qualitative data analysis utilized an inductive, data-driven approach. Four themes emerged. First, mothers' perception of risk of postpartum depression (PPD) changed over time and with subsequent children. Theme two focused on identity loss. Third, the stay-at-home parent often feels unrecognized by their partner. Fourth, a PPD prevention class for parents should include certain key elements. These themes can aid practitioners in prioritizing the needs of parents during the perinatal period.

Anxiety among fathers during the prenatal and postpartum period: a meta-analysis

INTRODUCTION

The purpose of this review was to determine the prevalence of anxiety among fathers during the perinatal (pre- and post-natal) period.

METHODS

A systematic search was conducted to identify studies published between 1995-2020. One hundred and seventy-two of the records met inclusion criteria and full texts were screened for eligibility. The authors followed PRISMA guidelines to extract the data.

RESULTS

A total of 23 studies, representing 40,124 participants, are included in this meta-analysis. The overall random effects estimate of paternal perinatal anxiety was 10.69% (95% confidence interval (CI): 8.14 - 13.91%). Rates of paternal perinatal anxiety demonstrated significant heterogeneity that was large in magnitude (Q = 304,494, p < .001, I² = 99.93 and τ² = .5381). Study quality rating did not appear to moderate rates of paternal perinatal anxiety (low: 10.74%; 95% CI: 6.56-17.11%; high: 10.65%; 95% CI: 6.02- 18.15%).

DISCUSSION

Paternal perinatal anxiety rates in this meta-analysis are considerably higher than the global WHO regional prevalence rates for anxiety among men suggesting the transition into parenthood may place men at greater risk for anxiety.

De novo polyamine synthesis supports metabolic and functional responses in activated murine NK cells

Cellular metabolism is dynamically regulated in NK cells and strongly influences their responses. Metabolic dysfunction is linked to defective NK cell responses in diseases such as obesity and cancer. The transcription factors, sterol regulatory element binding protein (SREBP) and cMyc, are crucial for controlling NK cell metabolic and functional responses, though the mechanisms involved are not fully understood. This study reveals a new role for SREBP in NK cells in supporting de novo polyamine synthesis through facilitating elevated cMyc expression. Polyamines have diverse roles and their de novo synthesis is required for NK cell glycolytic and oxidative metabolism and to support optimal NK cell effector functions. When NK cells with impaired SREBP activity were supplemented with exogenous polyamines, NK cell metabolic defects were not rescued but these NK cells displayed significant improvement in some effector functions. One role for polyamines is in the control of protein translation where spermidine supports the posttranslational hypusination of translation factor eIF5a. Pharmacological inhibition of hypusination also impacts upon NK cell metabolism and effector function. Considering recent evidence that cholesterol-rich tumor microenvironments inhibit SREBP activation and drive lymphocyte dysfunction, this study provides key mechanistic insight into this tumor-evasion strategy.

Mental Health During the COVID-19 Pandemic in the United States: Online Survey

Background

The COVID-19 pandemic has had numerous worldwide effects. In the United States, there have been 8.3 million cases and nearly 222,000 deaths as of October 21, 2020. Based on previous studies of mental health during outbreaks, the mental health of the population will be negatively affected in the aftermath of this pandemic. The long-term nature of this pandemic may lead to unforeseen mental health outcomes and/or unexpected relationships between demographic factors and mental health outcomes.

Objective

This research focused on assessing the mental health status of adults in the United States during the early weeks of an unfolding pandemic.

Methods

Data was collected from English-speaking adults from early April to early June 2020 using an online survey. The final convenience sample included 1083 US residents. The 71-item survey consisted of demographic questions, mental health and well-being measures, a coping mechanisms checklist, and questions about COVID-19–specific concerns. Hierarchical multivariable logistic regression was used to explore associations among demographic variables and mental health outcomes. Hierarchical linear regression was conducted to examine associations among demographic variables, COVID-19–specific concerns, and mental health and well-being outcomes.

Results

Approximately 50% (536/1076) of the US sample was aged ≥45 years. Most of the sample was White (1013/1054, 96%), non-Hispanic (985/1058, 93%), and female (884/1073, 82%). Participants reported high rates of depression (295/1034, 29%), anxiety (342/1007, 34%), and stress (773/1058, 73%). Older individuals were less likely to report depressive symptomology (OR 0.78, P<.001) and anxiety symptomology (OR 0.72, P<.001); in addition, they had lower stress scores (–0.15 points, SE 0.01, P<.001) and increased well-being scores (1.86 points, SE 0.22, P<.001). Individuals who were no longer working due to COVID-19 were 2.25 times more likely to report symptoms of depression (P=.02), had a 0.51-point increase in stress (SE 0.17, P=.02), and a 3.9-point decrease in well-being scores (SE 1.49, P=.009) compared to individuals who were working remotely before and after COVID-19. Individuals who had partial or no insurance coverage were 2-3 times more likely to report depressive symptomology compared to individuals with full coverage (P=.02 and P=.01, respectively). Individuals who were on Medicare/Medicaid and individuals with no coverage were 1.97 and 4.48 times more likely to report moderate or severe anxiety, respectively (P=.03 and P=.01, respectively). Financial and food access concerns were significantly and positively related to depression, anxiety, and stress (all P<.05), and significantly negatively related to well-being (both P<.001). Economy, illness, and death concerns were significantly positively related to overall stress scores (all P<.05).

Conclusions

Our findings suggest that many US residents are experiencing high stress, depressive, and anxiety symptomatology, especially those who are underinsured, uninsured, or unemployed. Longitudinal investigation of these variables is recommended. Health practitioners may provide opportunities to allay concerns or offer coping techniques to individuals in need of mental health care. These messages should be shared in person and through practice websites and social media.

A United Kingdom Multicenter Study of Icodextrin in Continuous Ambulatory Peritoneal Dialysis

While glucose remains the only osmotic agent used universally for peritoneal dialysis, its various shortcomings for the long dwell equilibration continuous ambulatory peritoneal dialysis (CAPD) has led to a search for alternative agents. The large molecular weight group has been of interest, because these agents theoretically would lead to greater ultrafiltration and a better metabolic profile. Mostsubstances (dextrans, charged macromolecules) have been found unsuitable for reasons of insolubility, allergenicity, and peritoneal toxicity. Short-chain polypeptides have been studied in humans, but the experience is limited, and there is the potential for allergenicity with long-term use.

The only large molecular weight agent that has been studied in some detail but hitherto in one center only and in a limited number of patients is glucose polymer (generic name, icodextrin). Because of the promise shown by these initial studies, a randomized controlled multicenter investigation of icodextrin in CAPD (MIDAS Study Group) was undertaken to evaluate the long-term safety and efficacy by comparing daily overnight (8 12 hours) use of a slightly hypo-osmolar solution (282 mOsm/ kg) with 1.36% (346 mOsm/kg) and 3.86% (484 mOsm/kg) glucose exchanges. Over a 6-month period 209 patients from 11 centers in the United Kingdom were randomized, with 106 allocated to receive icodextrin (study group) and 103 to remain on glucose (control group). One hundred and thirty-eight patients completed the 6-month study (71 control, 67 study).

The mean net ultrafiltration overnight with icodextrin was 3.5 times greater than 1.36% at 8 hours and 5.5 times greater at 12 hours (p<0.0001), but no different from that of 3.86% glucose at 8 and 12 hours (although for the latter dwell the net mean ultrafiltration volume was greater by about 140 mL). Biochemical profiles were no different except for a small fall in serum sodium and chloride in the icodextrin group. The mean serum maltose rose to a steady-state level of 1.2 g/L within 2 weeks and remained stable. The mean carbohydrate absorbed for icodextrin (29±5 g) was lower than with 3.86% glucose (62±5 g). The use of icodextrin did not increase the incidence of peritonitis, nor did it alter its outcome, affect uptake of icodextrin from the peritoneum, alter serum osmolality or sodium levels. There were no adverse effects associated with the use of icodextrin, and the overall CAPD-related symptom score was significantly better for icodextrin than control subjects.

This study and subsequent extensive use and clinical experience has demonstrated that the daily use of an iso-osmolar icodextrin solution is generally well tolerated, effective, and could replace the overnight use of hyperosmotic glucose solution. Its use was of equal efficacy in peritonitis and in diabetic patients. The elevated levels of maltose did not appear to have any clinical side effects.

Peritonitis Occurrence in a Multicenter Study of Icodextrin and Glucose in Capd

Objective

To compare peritonitis occurrence and outcome in a large U.K. study Multicentre Investigation of Icodextrin in Ambulatory Dialysis (MIDAS).

Design

Prospective, randomized, controlled 6-month comparison of icodextrin with glucose for the long dwell in continuous ambulatory peritoneal dialysis (CAPD) patients.

Setting

Eleven CAPD units in U.K. teaching hospitals.

Patients

A total of 209 patients established on CAPD for at least 3 months (103 control, 106 icodextrin). Twentythree control (C) and 22 icodextrin (I) patients experienced peritonitis during the study.

Intervention

Patients who had peritonitis remained on treatment (unless CAPD was withdrawn, temporarily or permanently).

Main Outcome Measures

The main outcome measures were the rate of peritonitis and duration of CAPD treatment prestudy; the rate of peritonitis episodes and their outcome during study; the effect of peritonitis on laboratory variables, serum icodextrin metabolites, and ultrafiltration efficacy.

Results

Prestudy: Nine (39%) of C but 14 (64%) of I patients had suffered previous peritonitis episode(s), with overall rates of 0.58 and 0.78 episodes per patientyear, respectively.

During study

There were 31 C episodes and 35 I episodes, with overall rates of 0.76 and 0.93 per patientyear, respectively. The increase in the C and I groups was 31% and 19%, respectively. Serum osmolality and sodium levels were unaffected by peritonitis, and there was no increase in serum icodextrin metabolites during peritonitis. Overnight ultrafiltration volume during peritonitis (mean±SD) declined slightly from 218±354 mL to 185±299 mL (NS) in the control group, but increased in the icodextrin group from 570±146 mL to 723±218 mL (p < 0.01).

Conclusions

Using icodextrin for the long dwell in CAPD does not increase the rate of peritonitis, nor does it alter the outcome of peritonitis. Peritonitis does not affect uptake of icodextrin from the peritoneum.

Interleukin-6 Levels Decrease in Effluent from Patients Dialyzed with Bicarbonate/Lactate–Based Peritoneal Dialysis Solutions

♦ Objective

Conventional lactate-buffered peritoneal dialysis (PD) solutions have several bioincompatible characteristics, including acidic pH, lactate buffer, and the presence of glucose degradation products (GDPs). These characteristics, along with inflammation, are believed to contribute to membrane dysfunction in peritoneal dialysis patients. A new PD solution containing a bicarbonate/ lactate buffer system with physiologic pH and low GDPs has shown improved biocompatibility in both in vitro and ex vivo studies. In the present study, the concentrations of cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα), and vascular endothelial growth factor (VEGF), were measured in timed overnight effluents from PD patients continuously dialyzed with either lactate-based control solution (C) or bicarbonate/lactate–based solution (B/L) for 6 months.

♦ Methods

Effluents from 92 continuous ambulatory peritoneal dialysis (CAPD) patients were collected when the patients were entered into the study (baseline, all patients on C for more than 3 months), and at 3 and 6 months following randomization to C ( n = 31) or to B/L ( n = 61). Effluent samples were filtered, stored frozen, and then assayed for IL-6, TNFα, and VEGF by ELISA.

♦ Results

A significant decrease in effluent IL-6 was seen at 3 months and at 6 months in the B/L-treated patients. Levels of VEGF were significantly reduced at 3 months. No changes in the levels of IL-6 or VEGF were seen in the C-treated patients, and no changes in TNFα were seen in either group over time.

♦ Conclusions

Treatment with B/L is associated with decreased IL-6 synthesis and decreased VEGF secretion. The data suggest that the use of B/L solution is associated with reduced intraperitoneal inflammation and potential for angiogenesis. The use of B/L solution may, over time, help to restore peritoneal homeostasis and therefore preserve the function of the membrane in peritoneal dialysis.

A Mixed-Methods Pilot Study of Perinatal Risk and Resilience During COVID-19

Introduction/Objectives: National guidelines underscore the need for improvement in the detection and treatment of mood disorders in the perinatal period. Exposure to disasters can amplify perinatal mood disorders and even have intergenerational impacts. The primary aim of this pilot study was to use mixed-methods to better understand the mental health and well-being effects of the coronavirus disease 2019 (COVID-19) pandemic, as well as sources of resilience, among women during the perinatal period. Methods: The study team used a simultaneous exploratory mixed-methods design to investigate the primary objective. Thirty-one pregnant and postpartum women participated in phone interviews and were invited to complete an online survey which included validated mental health and well-being measures. Results: Approximately 12% of the sample reported high depressive symptomatology and 60% reported moderate or severe anxiety. Forty percent of the sample reported being lonely. The primary themes related to stress were uncertainty surrounding perinatal care, exposure risk for both mother and baby, inconsistent messaging from information sources and lack of support networks. Participants identified various sources of resilience, including the use of virtual communication platforms, engaging in self-care behaviors (eg, adequate sleep, physical activity, and healthy eating), partner emotional support, being outdoors, gratitude, and adhering to structures and routines. Conclusions: Since the onset of COVID-19, many pregnant and postpartum women report struggling with stress, depression, and anxiety symptomatology. Findings from this pilot study begin to inform future intervention work to best support this highly vulnerable population.

Accelerated Hypertriglyceridemia in Patients on Continuous Ambulatory Peritoneal Dialysis - A Preventable Abnormality

Increasing hypertriglyceridemia is a recognised complication of CAPD. To investigate the etiology lipid clearance studies using the intravenous fat tolerance test were performed in control subjects and in uremic patients before and after six months CAPD treatment. Oral carbohydrate intake was restricted and the use of hypertonic dialysate kept to a minimum. Although serum triglycerides were elevated in the uremic patients before CAPD (3.1 ± 0.3 mMol/L) no further increase occurred during therapy. Oral carbohydrate intake was restricted to 240–250 Gms/24 hrs and hypertonic dialysate to 5.7 ± 4.1% of the total. There were no significant changes in fractional removal rate of lipid. Therefore further increases in serum triglycerides in CAPD may be prevented by simple dietary manoeuvres.

Anal metastasis as the sentinel and isolated presentation of invasive ductal breast carcinoma

Breast cancer currently affects 1 in 8 women in the UK during their lifetime. Common sites for breast cancer metastasis include the axillary lymph nodes, bones, lung, liver, brain, soft tissue and adrenal glands. There is well documented evidence detailing breast metastasis to the gastrointestinal tract but anal metastasis is exceptionally rare. We present the case of a 78-year-old woman with an anal metastasis as the sentinel and isolated presentation of an invasive ductal breast carcinoma. As advances in the treatment of breast cancer improve, and with an ageing and expanding population, there will be an increasing number of cancer survivors, and more of these unusual presentations may be encountered in the future.

Cardiovascular effects of methacholine-induced airway obstruction in man

Cardiovascular disease is the most frequent cause of death in people with chronic respiratory disease. The cause of this association has been attributed to airway obstruction leading to cardiovascular dysfunction (increased central blood pressure (BP) and aortic stiffness). However, this has never been experimentally tested. Methacholine is routinely used to stimulate airway function changes that mimic airway pathology. This study aimed to determine the cardiovascular effects of methacholine-induced airway obstruction. Fifteen healthy young adults (aged 22.9±2.5 years; 4 male; mean±S.D.) underwent a bronchial challenge test (randomized, blinded, cross-over design) in which they received nebulized methacholine inhalation in serially increasing concentrations (from 0.39 to 25 mg/ml) or saline (0.9%; control) on two separate days. Bronchoconstriction was assessed by forced expiratory volume at one second (FEV1) and cardiovascular effects by augmentation index, brachial BP, central BP, heart rate and aortic stiffness. Methacholine significantly decreased FEV1 from baseline to peak inhaled concentration compared with saline (-0.48±0.34 vs. -0.07±0.16 L; p<0.001), but there was no between-group change in augmentation index (1.6±7.0 vs. 3.7±10.2% p=0.49), brachial systolic BP (-3.3±7.6 vs. -4.7±5.7 mmHg; p=0.59), central systolic BP (-1.1±5.2 vs. -0.3±5.5 mmHg; p=0.73), heart rate (0.4±7.1 vs. -0.8±6.6 bpm; p=0.45) or aortic stiffness (0.2±1.3 vs. 0.8±1.8 m/s; p=0.20; n=12). Thus, methacholine induced airway obstruction does not acutely change brachial BP or central haemodynamics. This finding refutes the notion that airway obstruction per se leads to cardiovascular dysfunction, at least in healthy individuals in the acute setting.

Volatile organic compounds in runners near a roadway: increased blood levels after short-duration exercise

OBJECTIVE

To determine if non-elite athletes undertaking short duration running exercise adjacent to a busy roadway experience increased blood levels of common pollutant volatile organic compounds (benzene, toluene, ethylbenzene and xylene (BTEX)).

DESIGN AND SETTING

The study was observational in design. Participants (nine males/one female non-elite athletes) ran for 20 min, near a busy roadway along a 100 m defined course at their own pace. Blood levels of BTEX were determined both pre- and post-exercise by SPME-GC-MS. Environmental BTEX levels were determined by passive adsorption samplers.

RESULTS

Subjects completed a mean (range) distance of 4.4 (3.4 to 5.2) km over 20 min (4.5 (3.8 to 5.9) min/km pace), with a mean (SD) exercise intensity of 93 (2.3)% HR(max), and mean (SD) ventilation significantly elevated compared with resting levels (86.2 (2.3) vs 8.7 (0.9) l/min; p<0.001). The mean (SD) environmental levels (time weighted average) were determined as 53.1 (4.2), 428 (83), and 80.0 (3.7) microg/m(3) for toluene, ethylbenzene and xylenes, respectively, while benzene was below the detectable limit due to the short exposure period. Significant increases in blood BTEX levels were observed in runners between pre- and postexercise for toluene (mean increase of 1.4 ng/ml; p=0.002), ethylbenzene (0.7 ng/ml; p=0.0003), m/p-xylene (2.0 ng/ml; p=0.004) and o-xylene (1.1 ng/ml; p=0.002), but no change was observed for benzene.

CONCLUSIONS

Blood BTEX levels are increased during high-intensity exercise such as running undertaken in areas with BTEX pollution, even with a short duration of exercise. This may have health implications for runners who regularly exercise near roadways.

A novel imaging technique as an adjunct to the in vivo diagnosis of nonmelanoma skin cancer

BACKGROUND

Spectrophotometric intracutaneous analysis (SIAscopy) is a light-based imaging system capable of producing rapid images of melanin, blood and collagen of the skin. Although the SIAscope has been investigated for melanoma diagnosis, no formal study has been conducted to determine its use in the diagnosis of nonmelanoma skin cancer (NMSC).

OBJECTIVES

A prospective study was conducted to investigate the potential for the SIAscope to diagnose NMSC.

METHODS

In total, 302 consecutive patients were recruited into the study, 363 lesions being scanned. Logistic regression analysis was used to construct a predictive model for NMSC diagnosis and receiver-operator characteristic curves were used to assess overall accuracy of the model.

RESULTS

A sensitivity of 98.0%, specificity of 95.7% and overall accuracy of 98.2% was found for NMSC diagnosis by the SIAscope model.

CONCLUSIONS

Results suggest that the SIAscope may be a useful adjunct in the diagnosis of NMSC.

Dilated cardiomyopathy masquerading as long QT syndrome

Atrioventricular block has been described in association with cases of long QT syndrome and mortality is increased in this subgroup. We describe an infant with congenital QT prolongation and atrioventricular block with normal cardiac function, leading to the initial diagnosis of long QT syndrome. She subsequently developed dilated cardiomyopathy requiring cardiac transplantation. We postulate that the presenting electrocardiograph abnormalities were early manifestations of the myocardial disease, preceding the development of myocardial dysfunction by several months. The need for heightened surveillance in cases of QT prolongation with atrioventricular block is amplified by the possibility of an evolving cardiomyopathy.

Post-hoc diagnosis of congenital long QT syndrome in patients with tetralogy of Fallot

This report describes two patients diagnosed with congenital long QT syndrome after surgical repair of tetralogy of Fallot. Despite the fact that both patients had preoperative electrocardiograms demonstrating QT prolongation, neither was diagnosed until long after their surgeries, when they or their relatives presented with symptoms of long QT syndrome. A brief discussion highlights the reasons why long QT syndrome may be overlooked in patients with structural heart defects and the clinical importance of identifying these patients preoperatively.

Decreased lung capillary blood volume post-exercise is compensated by increased membrane diffusing capacity

The diffusing capacity of the lung for carbon monoxide (DLCO) decreases to below the pre-exercise value in the hours following a bout of intense exercise. Two mechanisms have been proposed: (1) development of pulmonary oedema and (2) redistribution of central blood volume to peripheral muscles causing a reduction in pulmonary capillary blood volume ( V(c)). In the present study DLCO, V(c) and the membrane diffusing capacity ( D(m)) were measured in nine healthy females using a rebreathing method, in contrast to the single breath technique employed in previous studies. DLCO, V(c) and D(m) were measured before and at 1, 2, 3, 16 and 24 h following maximal treadmill exercise. Compared with pre-exercise values, DLCO was depressed by up to 8.9 (3.0)% ( P<0.05) for the first 3 h following exercise, but had returned to pre-exercise values by 16 h post-exercise. V(c) fell by 21.2 (4.1)% ( P<0.05) at 3 h post-exercise, but at the same time D(m) increased by 14.7 (9.1)%. It was concluded that: (1) the increase in D(m) made it unlikely that the fall in DLCO was due to interstitial oedema and injury to the blood gas barrier; (2) on the other hand, the reduction in DLCO following exercise was consistent with a redistribution of blood away from the lungs; and (3) the trend for D(m) and V(c) to reciprocate one another indicates a situation in which a fall in V(c) nevertheless promotes gas transfer at the respiratory membrane. It is suggested that this effect is brought about by the reorientation of red blood cells within the pulmonary capillaries following exercise.

Nifedipine improves immediate, and 6- and 12-month graft function in cyclosporin A (CyA) treated renal allograft recipients

To investigate the effect of oral nifedipine, a calcium channel blocker known not to modify cyclosporin A (CyA) pharmacokinetics, on immediate transplant function and CyA nephrotoxicity, 68 adult renal transplant recipients were pre-operatively randomized to one of three regimes: A (high-dose CyA, initial dose 17 mg/kg per day, maintenance dose 7 mg/kg per day); B (regime A plus oral nifedipine); C low-dose CyA, initial dose 10 mg/kg per day, maintenance 4 mg/kg per day plus azathioprine 1 mg/kg per day). All three groups received identical steroid regimes. Calcium channel blockers of all types were avoided in groups A and C. Delayed graft function (dialysis dependence by day 4) was seen least frequently in group B (P < 0.02). Group B had improved graft function at 6 months compared with group A, identified by differences in serum creatinine (P < 0.05), GFR (P < 0.01) and ERPF (P < 0.05). Similar differences in serum creatinine (P < 0.05) and GFR (P < 0.05) were also identified at 12 months. Group C also had better 6- and 12-month GFR values than group A (P < 0.05 each). The three groups did not differ in donor or recipient age, HLA matching, ischaemic or anastomosis times, frequency of early rejection or whole-blood CyA levels. These results indicate that nifedipine significantly improves immediate and medium-term graft function.

Impaired system A amino acid transport mimics the catabolic effects of acid in L6 cells

BACKGROUND

Metabolic acidaemia stimulates protein catabolism in skeletal muscle cells, leading to muscle wasting. As this occurs without decreasing cytosolic pH, the initial signal is unclear. A possible explanation is that extracellular pH acts on solute transporters at the cell surface, inhibiting nutrient influx.

DESIGN

Influx through glucose and Pi transporters and System A amino acid transporters into L6 skeletal muscle cells was assessed using 3H-2-deoxyglucose (2-DG), 33Pi and 14C-methylaminoisobutyrate (MeAIB), respectively. Protein degradation (PD) was assessed from 14C efflux from cells prelabelled with 14C-Phe. Branched-chain amino acids and Phe were assayed by selective fluorimetric assays.

RESULTS

While acid (pH 7.1) had little immediate effect on 2-DG or 33Pi influx, exposure to pH 7.1 rapidly inhibited MeAIB influx. To determine whether System A inhibition was sufficient to trigger PD, it was blocked at pH 7.5 by a saturating dose (10 mmol L(-1)) of nonmetabolisable substrate (MeAIB). Like acid, this increased PD and decreased total protein. It also mimicked the decreases in protein synthesis, DNA synthesis, glucose transport and glycolysis, and depletion of branched-chain amino acids and Phe, which are induced in L6 by acid. The onset of inhibition of PD by an extracellular Gln load was retarded at pH 7.1, and stimulation of PD by acid was negligible if PD had already been stimulated by Gln depletion. The stimulatory effect of MeAIB on PD was selectively blunted by an excess of Gln, whereas the inhibitory effect of Gln on PD was blocked by excess MeAIB.

CONCLUSIONS

The similarity of changes in response to MeAIB and acid implies that these share a common intracellular signalling pathway triggered by inhibition of System A. Even though System A is only a minor contributor to total Gln influx in L6 cells, it is suggested that blockade of System A with acid or MeAIB induces a catabolic state by denying Gln access to a key intracellular regulatory site.

Reduced expression of cyclin-dependent kinase inhibitor p27Kip1 in feline lymphoma

Expression of p27Kip1 was identified in feline lymphoid tissues by immunohistochemistry. In normal lymphoid tissues, p27Kip1 was detected as a distinct nuclear stain in lymphocytes of the follicular mantle zone and interfollicular small lymphocytes, whereas activated lymphoblasts in the germinal center were negative. Lymphoid hyperplasia was similarly immunolabeled but with an expanded mantle zone and marginal zone of p27Kip1-reactive lymphocytes. Both T- and B-cell lymphomas lacked p27Kip1 immunolabel and were determined to be proliferative based on immunohistochemical detection of the Ki-67 antigen. Scattered p27Kip1-immunolabeled lymphocytes were detected throughout the lamina propria of most specimens characterized as lymphoplasmacytic enteritis. The results of this study suggest that the antiproliferative effect of the cell cycle regulator p27Kip1 is abrogated in feline lymphoma, presumably allowing cells to bypass the G1-S checkpoint of the cell cycle.

Effects of glucose dialysate on extracellular matrix production by human peritoneal mesothelial cells (HPMC): the role of TGF-beta

BACKGROUND

Dialysate glucose has been implicated in the loss of peritoneal membrane function seen in long-term CAPD patients.

METHODS

In order to investigate this in vitro, human peritoneal mesothelial cells (HPMC) were cultured in a 50:50 mix of dialysis solution and M199 for 12 h. The dialysate was laboratory manufactured and designed to be identical in composition to PD4 (LAB). The final glucose concentration ranged between 5 and 40 mmol/l. Experiments were conducted in the presence and absence of an anti-transforming growth factor-beta (TGF-beta) antibody. Cell viability was measured by lactate dehydrogenase (LDH) release. Fibronectin (FN) and TGF-beta protein were measured by ELISA, and FN gene expression was measured by Northern analysis. Separately, the effects of recombinant TGF-beta(1) added to M199: dialysate at 5 mmol/l glucose were investigated.

RESULTS

Forty millimoles per litre d-glucose LAB caused a decrease in cell viability, as evidenced by an increase in LDH release (6.0+/-1.3 vs 2.6+/-0.7%). This effect was dependent on osmolality. Forty millimoles per litre d-glucose LAB stimulated a 15.4+/-4.6% increase in FN, a 46.5+/-18.3% increase in TGF-beta protein (both P<0.05), and 1.4+/-0.09-fold increase in FN mRNA compared with 5 mmol/l d-glucose LAB. Exogenous TGF-beta 0-1 ng/ml induced a dose-dependent increase in FN protein (280+/-45% increase at TGF-beta 1 ng/ml, P<0.0001), and FN mRNA levels (10.0+/-1.8-fold at TGF-beta 1 ng/ml). The increase in FN in response to 40 mmol/l glucose was significantly reduced by anti-TGF-beta antibody to levels not different from control (93.8+/-6.6%, P<0.05 vs no Ab).

CONCLUSIONS

These data suggest that the pro-fibrotic effect of glucose dialysate on HPMC is mediated through stimulation of TGF-beta, which promotes FN gene expression and protein production.

Leucine suppresses acid-induced protein wasting in L6 rat muscle cells

BACKGROUND

Metabolic acidosis induces protein wasting in skeletal muscle cells, accompanied by decreased glycolysis and compensatory increased consumption of other metabolic fuels, implying that protein wasting arises from fuel starvation and might be rectified by fuel supplements. Design To test this hypothesis, total protein and protein degradation (release of 14C-phenylalanine) were measured in L6 skeletal muscle cells cultured in Eagle's Minimum Essential Medium at pH 7.1-7.5 for 3 days with metabolic inhibitors or metabolic fuel supplements.

RESULTS

Inducing metabolic fuel starvation with inhibitors (1 mmol L(-1) 2-deoxyglucose or 0.1 mmol L(-1) KCN [potassium cyanide]) failed to stimulate protein degradation or net protein wasting under nonacidaemic conditions (pH 7.5). Conversely metabolic fuel supplements (1 mmol L(-1) octanoate, pyruvate or alanine) failed to increase the protein content of the cultures at any pH tested, in spite of significant consumption of the fuels by the cells. Only leucine (1-3 mmol L(-1)) increased protein content and suppressed protein degradation in opposition to the catabolic effect of acidaemia (pH 7.1). Conclusion Leucine exerts a beneficial anabolic effect on cultured skeletal muscle cells in the face of metabolic acidaemia. The failure of other metabolic fuels to do this, and of the metabolic inhibitors to exert a catabolic effect, suggests that leucine acts as a specific modulator of protein turnover and not as a nonspecific source of carbon for oxidation as a fuel.

Role of diuretics in the preservation of residual renal function in patients on continuous ambulatory peritoneal dialysis

BACKGROUND

Patients on continuous ambulatory peritoneal dialysis (CAPD) are dependent on residual renal function for solute and water clearances, and this declines with time on dialysis. Loop diuretics have been postulated to slow this decline.

METHODS

Sixty-one patients new to dialysis were randomly assigned to either furosemide 250 mg every day or no furosemide at the time of CAPD training and were followed prospectively. Urine volume (UV), urea clearance (C(Urea)), and creatinine clearance on cimetidine (C(Cr)) were measured at randomization at six months and at one year. Patients underwent a standard four-hour peritoneum equilibrium test, and total body water was measured by bioelectrical impedance. Results were expressed on an intention-to-treat basis.

RESULTS

UV, C(Cr), and C(Urea) were similar at randomization (1020 +/- 104 vs. 1040 +/- 130 mL/24 hours, 4.95 +/- 0.51 vs. 4.07 +/- 0.40 mL/min/1.73 m2, 0.91 +/- 0.09 vs. 0.84 +/- 0.08, diuretic vs. control). UV in the diuretic-treated group increased, whereas in the control group, it declined (+176 vs. -200 mL/24 hours at 6 months and +48.8 vs. -305 mL/24 hours at 1 year, P < 0.05). C(Cr) and C(Urea) declined at a constant rate and were unaffected by diuretic administration (0.12 +/- 0.05 vs. 0.071 +/- 0.04 mL/min/1.73 m2/month, 0.020 +/- 0.01 vs. 0.019 +/- 0.01 per month). Urinary sodium excretion increased in the diuretic group and declined in the control group (+0.72 +/- 0.85 vs. -2.56 +/- 1.31 mmol/24 hours/month, P = 0.04). Body weight rose in both groups (4.3 vs. 3.0 kg), but the percentage of total body weight rose in the control group and remained constant in the diuretic group (52 +/- 2.4 vs. 64 +/- 6.6%, P = 0.10).

CONCLUSIONS

Long-term furosemide produces a significant increase in UV over 12 months when on CAPD and may result in clinically significant improvement in fluid balance. However, furosemide has no effect on preserving residual renal function.

End-stage renal disease, atherosclerosis, and cardiovascular mortality: is C-reactive protein the missing link?

In uremic patients, the morbidity and mortality of cardiovascular disease are substantially higher than in the general population. This has led to the formulation of an 'accelerated atherogenesis' hypothesis in uremic patients and has been commonly linked with the metabolic alterations associated with uremia. Advancement in the understanding of the pathogenesis of atherosclerotic vascular disease now suggests a central contribution of inflammation to atherogenesis, with involvement of a number of key mediators and markers of the inflammatory process. Recent epidemiological data have documented associations between C-reactive protein (CRP), the prototypical acute phase response protein, and cardiovascular disease in general population. Given the lipoprotein binding and complement activation functions of CRP and its localization in atherosclerotic vessels, there is a strong likelihood that CRP may be involved in the atherosclerotic process. The uremic state is associated with an altered immune response, which is associated with elevated proinflammatory cytokine levels. CRP concentrations are increased in a significant proportion of end-stage renal disease patients and have been associated with certain clinical outcome measures, including all-cause and cardiovascular mortality. This review outlines the evidence linking CRP with atherosclerosis and proposes that elevated CRP concentrations may be involved in the initiation and progression of accelerated atherosclerosis in uremia.

Turnover of human tubular cells exposed to proteins in vivo and in vitro

BACKGROUND

The cause of tubulointerstitial pathology in glomerular disease is uncertain. Proteinuria may be a causative factor and has been shown to increase the turnover of tubular cells in a rat model of proteinuria. We investigated whether increased tubular cell proliferation occurs in human proteinuric renal disease. A human cell culture model was used to investigate the effects of proteins on tubular cell turnover further.

METHODS

Tubular proliferation in renal biopsies from patients with membranous nephropathy (MN) and minimal change nephropathy (MCN) was assessed by in situ hybridization for histone mRNA. Proliferation was measured in polarized human tubular cell cultures using tritiated thymidine, following addition of proteins to the apical medium. Toxicity was assessed by lactate dehydrogenase (LDH) release and monolayer permeability to inulin.

RESULTS

Increased tubular cell histone mRNA expression occurred in biopsies in MN (3.0-fold increase, P < 0.002) and MCN (3.6-fold increase, P < 0.02). Serum proteins added to the medium on human tubular cell cultures increased thymidine uptake (1.3-fold, P < 0.005), LDH release (1.5-fold, P < 0.001), and monolayer permeability (1.7-fold, P < 0.005). The effects were reproduced by a fraction of molecular weight 40 to 100 kD, but not by pure albumin or transferrin.

CONCLUSIONS

Proliferation of tubular cells is associated with proteinuria in vivo and is caused by proteins in cell culture. Toxicity of proteins to tubular cells and increased cell turnover may contribute to tubulointerstitial pathology in glomerular disease.

Relationship between proteinuria and progressive renal disease

Numerous studies have shown a correlation between the degree of proteinuria and rate of progression of renal failure. This has led to the hypothesis that proteinuria may be an independent mediator of progression, rather than simply a marker of glomerular dysfunction. The mechanisms by which the presence of proteins in tubular fluid may promote the progression of chronic renal failure are not yet determined. However, the observation that proximal tubular cells reabsorb proteins from the tubular fluid has led to the suggestion that proteins or associated molecules may adversely affect tubular cell biological state. In this regard, it is of note that tubulointerstitial disease correlates better with the level of renal function than changes in the glomerulus. Further support for this hypothesis comes from the observations that strategies that reduce proteinuria, including control of hypertension, angiotensin-converting enzyme inhibition, and low-protein diets, reduce the rate of progression of renal failure.

Analysis of patients dying within one year of starting renal replacement therapy

BACKGROUND

The annual gross mortality of end-stage renal failure patients remains very high (approximately 15-20%) leading some to question the wisdom of accepting patients with limited prognosis for dialysis. We have reviewed the demographic and clinical characteristics of patients who died within a year of commencing renal replacement therapy (RRT) over a 5-year period to establish whether these patients could be identified at the start of therapy.

METHODS

Case notes of patients who died within 1 year of commencing RRT between 1st April, 1991 and 31st March, 1996 were reviewed. Comorbidity at the start of dialysis was used to classify patients into high-, medium- and low-risk groups using two published scales to determine whether either graded a high proportion of deaths as high risk. Factors such as age, social circumstances, cause of death, renal diagnosis and mode of dialysis were also analysed.

RESULTS

17.5% of patients commencing RRT died in the first year. Not all of these patients could be identified as high risk by comorbidity assessment at dialysis initiation - 50% of patients who died were classified by one scale as medium risk. Age did not clearly predict outcome, as 42% of patients who died were less than 65 years old.

CONCLUSION

These data suggest that it is difficult to use current risk stratifications to accurately predict outcome on RRT.

Secretion of chemokines and cytokines by human tubular epithelial cells in response to proteins

BACKGROUND

Chronic interstitial scarring contributes to the progression of renal failure in glomerular disease but its cause is unknown. The development of proteinuria could stimulate tubular cells to release cytokines, chemoattractants and matrix proteins into the interstitium, thus contributing to interstitial disease.

METHODS

Polarized human tubular epithelial cells were grown on permeable supports and exposed to serum proteins on their apical surface. The release of tumour necrosis factor alpha(TNFalpha), platelet derived growth factor (PDGF) and monocyte chemoattractant protein-1 (MCP-1) by the cells was measured using immunoassays.

RESULTS

Under control conditions there was polarized release of PDGF-AB with predominant basolateral secretion (basolateral to apical ratio 4.7+/-1.6). MCP-1 release was less polarized (ratio 1. 7+/-0.5). TNFalpha was not detected. Exposure of the cells to normal human serum proteins on their apical side increased basolateral release of PDGF-AB (1.7+/-0.4 fold) and MCP-1 (2.4+/-0.2 fold). Fractionation of the serum showed that this effect on human tubular epithelial cells was reproduced by a fraction of molecular weight 40-100 kDa. The predominant proteins in this fraction were albumin and transferrin but these purified proteins alone did not alter secretion of PDGF-AB or MCP-1.

CONCLUSION

This data demonstrates that human tubular cells exposed to proteins, which would be filtered in glomerular disease, produce inflammatory mediators with the potential to stimulate inflammation and scarring in the interstitium of the kidney.

Effects of acidosis on leptin secretion from 3T3-L1 adipocytes and on serum leptin in the uraemic rat

Marked hyperleptinaemia and metabolic acidosis are common findings in patients with chronic renal failure. In animal models, both leptin administration and acidosis reduce food intake. However, leptin causes loss of body fat, while acidosis induces muscle wasting. Whether a low pH and leptin production are related has not been studied. Leptin secretion was measured in cultured 3T3-L1 adipocytes exposed to acid or control pH for up to 96 h. In addition, serum leptin was compared between acidotic and bicarbonate-treated uraemic Wistar rats using the remnant model. Leptin levels in the culture medium were decreased at an acid pH of 7.1 compared with a control pH of 7.5 at 96 h (562+/-78 and 831+/-103 pg.48 h(-1). well(-1) respectively; mean+/-S.E.M.; P=0.037). Similarly, serum leptin in uraemic rats was found to be lower in the acidotic group than in the bicarbonate-treated group, although this observation fell just short of statistical significance (1273+/-171 compared with 2059+/-376 pg/ml; P=0.07). In conclusion, acidosis decreases leptin secretion from cultured adipocytes. Accordingly, acidotic uraemic rats seem to exhibit lower serum leptin levels than their bicarbonate-supplemented counterparts. This study is the first report providing a link between acidosis and leptin levels.

Measurement of urinary collagen cross-links indicate response to therapy in patients with breast cancer and bone metastases

Objective assessment of response in bone metastases from breast cancer using radiological techniques takes up to 6 months of treatment to be certain of a response, and sclerotic metastases are not evaluable. Standard serum and urinary tumour markers may not always be utilized to predict response, as they may not be elevated, and therefore may not change on treatment. The development of the urinary pyridinoline cross-link assays which measure mature bone breakdown products have been shown to be highly sensitive and specific as a measure of bone change in osteoporosis. We have measured pyridinoline (Pyr) and deoxypyridinoline (Dpyr) cross-links sequentially in 36 breast cancer patients with bone metastases, to determine if the measurement of these analytes predicts response at an earlier stage than radiological assessment. Response was assessed by UICC criteria. Seventeen women responded to hormonal therapy, whilst 19 developed progressive disease. Both Pyr and Dpyr increased sequentially in women with progressive disease with changes becoming apparent by 8 weeks (P<0.03). In responding women, cross-link levels did not change significantly. Pyr and Dpyr were more sensitive and specific than the standard serum tumour marker CA 15-3. Urinary cross-link measurements provide a novel objective method of assessing response to treatment in women with bone metastases. Initial elevated urinary cross-link markers identify patients who tend not to respond to changes in hormonal therapy.

Proteinuria induces tubular cell turnover: A potential mechanism for tubular atrophy

BACKGROUND

Proteinuria and tubular atrophy have both been closely linked with progressive renal failure. We hypothesized that apoptosis may be induced by tubular cell exposure to heavy proteinuria, potentially leading to tubular atrophy. Apoptosis was studied in a rat model of "pure" proteinuria, which does not induce renal impairment, namely protein-overload proteinuria.

METHODS

Adult female Lewis rats underwent intraperitoneal injection of 2 g of bovine serum albumin (BSA, N = 16) or sham saline injections (controls, N = 8) daily for seven days. Apoptosis was assessed at day 7 in tissue sections using in situ end labeling (ISEL) and electron microscopy. ISEL-positive nuclei (apoptotic particles) were counted in blinded fashion using image analysis with NIH Image. Cell proliferation was assessed by detection of mRNA for histone by in situ hybridization, followed by counting of positive cells using NIH Image.

RESULTS

Animals injected with saline showed very low levels of apoptosis on image analysis. BSA-injected rats had heavy proteinuria and showed both cortical and medullary apoptosis on ISEL. This was predominantly seen in the tubules and, to a lesser extent, in the interstitial compartment. Overall, the animals injected with BSA showed a significant 30-fold increase in the number of cortical apoptotic particles. Electron microscopy of tubular cells in a BSA-injected animal showed a progression of ultrastructural changes consistent with tubular cell apoptosis. The BSA-injected animals also displayed a significant increase in proximal tubular cell proliferation. This increased proliferation was less marked than the degree of apoptosis.

CONCLUSION

Protein-overload proteinuria in rats induces tubular cell apoptosis. This effect is only partially balanced by proliferation and potentially provides a direct mechanism whereby heavy proteinuria can induce tubular atrophy and progressive renal failure.

Seroprevalence of human granulocytic ehrlichiosis among permanent residents of northwestern Wisconsin

Four-hundred seventy-five permanent residents of Wisconsin were tested for antibodies to the agent of human granulocytic ehrlichiosis (HGE) by indirect immunofluorescent antibody (IFA) testing with Ehrlichia equi as antigen marker. Each resident completed a standard survey questionnaire about outdoor activities, animal and tick exposure, and any febrile illness during the preceding 12 months. Seventy-one serum samples (14.9%) contained E. equi antibodies. The mean IFA titer for seropositive residents was 250 (range, 80-10,240). Seropositive residents were older than seronegative ones (62 vs. 56 years; P = .019). None of the seropositive residents had a history suggestive of ehrlichiosis. There was no association between the IFA test outcome and specific demographic variables or history of tick bites. HGE appears to be a common subclinical or mild infection among residents in northwestern Wisconsin.

Impaired glycolysis and protein catabolism induced by acid in L6 rat muscle cells

BACKGROUND

In skeletal muscle, metabolic acidosis stimulates protein degradation and oxidation of branched-chain amino acids. This could occur to compensate for impairment of glucose utilization induced by acid.

METHODS

To test this hypothesis, glycolysis and protein degradation (release of [14C]-phenylalanine) were measured in L6 skeletal muscle cells cultured in Eagle's minimum essential medium at pH 7.1 or 7.5 for up to 3 days.

RESULTS

No marked changes in total DNA or in cell viability were detected, nor was there any significant effect on intracellular pH or the water content of the cells (which is thought to be a key regulator of protein turnover, especially in liver). In spite of this, acid stimulated protein degradation, induced net protein loss from the cultures, inhibited glucose uptake and glycolysis (lactate output) and was associated with increased [1-14C]-leucine oxidation. Effects on protein degradation and glycolysis were gradual, reaching a maximum after 20-30 h. To investigate whether glycolytic flux itself can influence protein degradation, increased glycolysis was simulated by adding glucose (20 mmol L-1) or pyruvate (1 mmol L-1) to the medium. At pH 7.1, neither addition had any effect on protein degradation.

CONCLUSION

Although acid-induced protein wasting is associated with impaired glycolysis, no obligatory coupling exists between glycolytic flux and protein degradation.