Pediatric pulmonary arterial hypertension due to a novel homozygous GDF2 missense variant affecting BMP9 processing and activity

Pulmonary arterial hypertension (PAH) is a rare and severe disorder characterized by progressive pulmonary vasculopathy. Growth differentiation factor (GDF)2 encodes the pro-protein bone morphogenetic protein (BMP) 9, activated after cleavage by endoproteases into an active mature form. BMP9, together with BMP10, are high-affinity ligands of activin receptor-like kinase 1 (ALK1) and BMP receptor type II (BMPR2). GDF2 mutations have been reported in idiopathic PAH with most patients being heterozygous carriers although rare homozygous cases have been described. The link between PAH occurrence and BMP9 or 10 expression level is still unclear. In this study, we describe a pediatric case of PAH also presenting with telangiectasias and epistaxis. The patient carries the novel homozygous GDF2 c.946A > G mutation, replacing the first arginine of BMP9's cleavage site (R316) by a glycine. We show that this mutation leads to an absence of circulating mature BMP9 and mature BMP9-10 heterodimers in the patient's plasma although pro-BMP9 is still detected at a similar level as controls. In vitro functional studies further demonstrated that the mutation R316G hampers the correct processing of BMP9, leading to the secretion of inactive pro-BMP9. The heterozygous carriers of the variant were asymptomatic, similarly to previous reports, reinforcing the hypothesis of modifiers preventing/driving PAH development in heterozygous carriers.

Function Preservation With Brachytherapy: Reviving the Art. Improving Quality of Life With Brachytherapy for Urological Malignancies

Brachytherapy for localised prostate, muscle-invasive bladder and penile cancer is well established, providing high tumour dose delivery and minimising normal tissue doses compared with external beam techniques. In prostate cancer, the main impact on quality of life relates to diminished sexual function and irritative or obstructive urinary symptoms, which are seen up to 15 years after treatment. Significant changes in bowel function are rare. Compared with radical prostatectomy or external beam radiotherapy, irritative or obstructive urinary symptoms are more prominent, whereas incontinence is less than after radical prostatectomy and bowel changes are less than after external beam radiotherapy. For muscle-invasive bladder cancer, when compared with radical cystectomy, although no difference is seen for urinary symptoms or fatigue, role and social functioning scores are higher and there is better post-treatment sexual function in both men and women. Compared with surgical treatment for penile cancer, brachytherapy results in better erectile function scores than after glansectomy and partial penectomy and high quality of life scores, with good satisfaction ratings for cosmetic appearance.

Early‐onset and severe Pulmonary Arterial Hypertension due to a novel compound heterozygous association of rare VHL mutations: a case report and review of existing data

Very rare cases of pulmonary arterial hypertension (PAH) have been linked to homozygous or compound heterozygous von Hippel–Lindau (VHL) tumor suppressor gene mutations, while heterozygous VHL mutations lead to VHL tumor syndrome. Although those entities are defined, the genotype–phenotype correlation is incompletely understood, and patient management recommendations are lacking. Here, we describe a case of severe early‐onset PAH due to a so‐far unreported compound heterozygous association of VHL mutations and review the existing data.

The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya

BACKGROUND

The COVID-19 pandemic has disrupted routine measles immunisation and supplementary immunisation activities (SIAs) in most countries including Kenya. We assessed the risk of measles outbreaks during the pandemic in Kenya as a case study for the African Region.

METHODS

Combining measles serological data, local contact patterns, and vaccination coverage into a cohort model, we predicted the age-adjusted population immunity in Kenya and estimated the probability of outbreaks when contact-reducing COVID-19 interventions are lifted. We considered various scenarios for reduced measles vaccination coverage from April 2020.

RESULTS

In February 2020, when a scheduled SIA was postponed, population immunity was close to the herd immunity threshold and the probability of a large outbreak was 34% (8-54). As the COVID-19 contact restrictions are nearly fully eased, from December 2020, the probability of a large measles outbreak will increase to 38% (19-54), 46% (30-59), and 54% (43-64) assuming a 15%, 50%, and 100% reduction in measles vaccination coverage. By December 2021, this risk increases further to 43% (25-56), 54% (43-63), and 67% (59-72) for the same coverage scenarios respectively. However, the increased risk of a measles outbreak following the lifting of all restrictions can be overcome by conducting a SIA with ≥ 95% coverage in under-fives.

CONCLUSION

While contact restrictions sufficient for SAR-CoV-2 control temporarily reduce measles transmissibility and the risk of an outbreak from a measles immunity gap, this risk rises rapidly once these restrictions are lifted. Implementing delayed SIAs will be critical for prevention of measles outbreaks given the roll-back of contact restrictions in Kenya.

Extreme Low Cytosolic pH Is a Signal for Cell Survival in Acid Stressed Yeast

Yeast biomass is recycled in the process of bioethanol production using treatment with dilute sulphuric acid to control the bacterial population. This treatment can lead to loss of cell viability, with consequences on the fermentation yield. Thus, the aim of this study was to define the functional cellular responses to inorganic acid stress. Saccharomyces cerevisiae strains with mutation in several signalling pathways, as well as cells expressing pH-sensitive GFP derivative ratiometric pHluorin, were tested for cell survival and cytosolic pH (pH_c) variation during exposure to low external pH (pH_ex). Mutants in calcium signalling and proton extrusion were transiently sensitive to low pH_ex, while the CWI slt2Δ mutant lost viability. Rescue of this mutant was observed when cells were exposed to extreme low pH_ex or glucose starvation and was dependent on the induced reduction of pH_c. Therefore, a lowered pH_c leads to a complete growth arrest, which protects the cells from lethal stress and keeps cells alive. Cytosolic pH is thus a signal that directs the growth stress-tolerance trade-off in yeast. A regulatory model was proposed to explain this mechanism, indicating the impairment of glucan synthesis as the primary cause of low pH_ex sensitivity.

On the origin of the extremely different solubilities of polyethers in water

The solubilities of polyethers are surprisingly counter-intuitive. The best-known example is the difference between polyethylene glycol ([-CH₂-CH₂-O-]_n) which is infinitely soluble, and polyoxymethylene ([-CH₂-O-]_n) which is completely insoluble in water, exactly the opposite of what one expects from the C/O ratios of these molecules. Similar anomalies exist for oligomeric and cyclic polyethers. To solve this apparent mystery, we use femtosecond vibrational and GHz dielectric spectroscopy with complementary ab initio calculations and molecular dynamics simulations. We find that the dynamics of water molecules solvating polyethers is fundamentally different depending on their C/O composition. The ab initio calculations and simulations show that this is not because of steric effects (as is commonly believed), but because the partial charge on the O atoms depends on the number of C atoms by which they are separated. Our results thus show that inductive effects can have a major impact on aqueous solubilities.

A β-Carbon elimination strategy for convenient in situ access to cyclopentadienyl metal complexes

The electronic and steric properties of tailored cyclopentadienyl (Cp) ligands are powerful handles to modulate the catalytic properties of their metal complexes. This requires the individual preparation, purification and storage of each ligand/metal combination. Alternative, ideally in situ, complexation protocols would be of high utility. We disclose a new approach to access Cp metal complexes. Common metal precursors rapidly react with cyclopentadienyl carbinols via β-carbon eliminations to directly give the Cp-metal complexes. An advantage of this is the direct and flexible use of storable pre-ligands. No auxiliary base is required and the Cp complexes can be prepared in situ in the reaction vessel for subsequent catalytic transformations.

A genome-wide screen in yeast identifies specific oxidative stress genes required for the maintenance of sub-cellular redox homeostasis

Maintenance of an optimal redox environment is critical for appropriate functioning of cellular processes and cell survival. Despite the importance of maintaining redox homeostasis, it is not clear how the optimal redox potential is sensed and set, and the processes that impact redox on a cellular/organellar level are poorly understood. The genetic bases of cellular redox homeostasis were investigated using a green fluorescent protein (GFP) based redox probe, roGFP2 and a pH sensitive GFP-based probe, pHluorin. The use of roGFP2, in conjunction with pHluorin, enabled determination of pH-adjusted sub-cellular redox potential in a non-invasive and real-time manner. A genome-wide screen using both the non-essential and essential gene collections was carried out in Saccharomyces cerevisiae using cytosolic-roGFP2 to identify factors essential for maintenance of cytosolic redox state under steady-state conditions. 102 genes of diverse function were identified that are required for maintenance of cytosolic redox state. Mutations in these genes led to shifts in the half-cell glutathione redox potential by 75-10 mV. Interestingly, some specific oxidative stress-response processes were identified as over-represented in the data set. Further investigation of the role of oxidative stress-responsive systems in sub-cellular redox homeostasis was conducted using roGFP2 constructs targeted to the mitochondrial matrix and peroxisome and E(GSH) was measured in cells in exponential and stationary phase. Analyses allowed for the identification of key redox systems on a sub-cellular level and the identification of novel genes involved in the regulation of cellular redox homeostasis.

Relationship between serum gamma-glutamyltransferase and chronic kidney disease in the United States adult population. Findings from the National Health and Nutrition Examination Survey 2001-2006

BACKGROUND AND AIMS

Elevated serum levels of gamma-glutamyltransferase (GGT) are a marker of liver injury, but may also be associated with other diseases and death. Currently, the association of serum GGT concentrations with chronic kidney disease has not been established in the U.S. general population.

METHODS AND RESULTS

We performed a cross-sectional analysis of data from the National Health and Nutrition Examination Survey 2001 through 2006 and examined the association between serum GGT concentrations and chronic kidney disease in a nationally representative sample of 13,188 adults aged 20 years or older. Glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease formula. The prevalence of chronic kidney disease defined as eGFR <60 ml/min/1.73 m(2) or abnormal albuminuria in those with eGFR ≥60 ml/min/1.73 m(2) was 13.9% (n = 1842). Serum GGT elevation was associated with an increased odds of chronic kidney disease (odds ratio 2.38, 95% confidence intervals 2.02-2.80, p<0.0001). After adjustment for demographics, comorbidities, daily alcohol consumption, lipid-lowering medications, viral hepatitis status and laboratory measures, the odds ratio of chronic kidney disease per log serum GGT increase was 1.79 (1.41, 2.27; p<0.0001).

CONCLUSIONS

These results show a strong, independent, relationship of increased serum GGT concentrations with chronic kidney disease in the US adult population.

Decrease of optic disc cupping and pallor of ocular hypertensives with timolol therapy

PURPOSE

The purpose of this study was to determine whether timolol drops compared to placebo drops had a significant effect on optic disc cupping and pallor in ocular hypertensives.

METHODS

Thirty-seven ocular hypertensives were randomly assigned to placebo or 0.5% timolol drops to both eyes in a double masked clinical trial. Measurements of ocular pressure and photographs of the optic disc for cupping by photogrammetry and pallor by computerized image analysis were made at about 3 month intervals, for 18 to 24 months of follow-up.

RESULTS

None of the subjects developed visual field loss when tested with the Goldmann perimeter by kinetic and static means at six month intervals. Subjects treated with timolol developed a significant decrease in ocular pressure and a significant decrease in optic disc cupping with a smaller decrease in pallor compared to subject treated with placebo. Multivariate analyses indicated that the decrease of optic disc cupping and pallor was not associated with the ocular pressure on treatment or the decrease in ocular pressure during the trial.

CONCLUSION

Timolol treatment was associated with a decrease in optic disc cupping and pallor. The effect of timolol appears to be related to mechanisms other than the decrease in ocular pressure.

Increase of retinal nerve fiber layer thickness in ocular hypertensives with timolol therapy

PURPOSE

The purpose of this study was to determine whether timolol drops compared to placebo drops had a significant effect on retinal nerve fiber layer thickness in ocular hypertensives.

METHODS

Thirty-seven ocular hypertensives were randomly assigned to receive placebo or 0.5% timolol drops to both eyes for 18 to 24 months in a double masked clinical trial. Measurements of ocular pressure and photographs of retinal nerve fiber layer using stereophotogrammetric techniques were made at about 3 month intervals for 18 to 24 months of follow-up.

RESULTS

None of the subjects developed visual field loss when tested with the Goldmann perimeter by kinetic and static means at six month intervals. Subjects treated with timolol had a significant decrease in ocular pressure and developed a significant increase in retinal nerve fiber layer thickness compared to subjects treated with placebo. Multivariate analyses indicated that the increase of retinal nerve layer thickness was not associated either with the ocular pressure on treatment or the decrease in ocular pressure on treatment.

CONCLUSION

Timolol treatment was associated with an increase of retinal nerve fiber thickness. The effect of timolol appears to be related to mechanisms other than the decrease in ocular pressure.

Presence and absence of follicle-stimulating hormone receptor mutations provide some insights into spontaneous ovarian hyperstimulation syndrome physiopathology

CONTEXT

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening complication of ovarian stimulation treatments. Moreover, four mutations of the FSH receptor (FSHr) were recently described in patients presenting with spontaneous OHSS (sOHSS) of the first trimester of pregnancy with normal levels of human chorionic gonadotropin (hCG).

OBJECTIVE

The objective of this study was to look for novel FSHr mutations in patients with sOHSS associated with different levels of hCG and TSH to 1) find new residues important for FSHr activation and specificity, and 2) better delineate the pathophysiology of the different presentations of sOHSS. DESIGN, INTERVENTION, AND PATIENTS: After blood sampling, we sequenced the FSHr from genomic leukocytes DNA from eight patients with sOHSS of the first or second trimester of pregnancy with normal or high hCG levels or with high TSH levels associated with severe hypothyroidism.

SETTING

This study was performed at a university laboratory.

MAIN OUTCOME MEASURE

The main outcome measure was FSHr sequencing and in vitro evaluation of the variation of cAMP production of FSHr mutants.

RESULTS

A new mutation was found in the patient with sOHSS of the first trimester of pregnancy with a normal hCG level: I5.54(545)T, in transmembrane helix V of the FSHr. When tested functionally, this mutant displayed promiscuous activation by both hCG and TSH together with detectable constitutive activity. In contrast, no mutations were found in the FSHr from patients with high hCG or TSH levels, indicating that for those seven patients, sOHSS results from the natural promiscuous stimulation of a wild-type FSHr by very high concentrations of hCG or TSH.

CONCLUSIONS

sOHSS can occur by at least three different pathophysiological mechanisms.

Low first postoperative day intraocular pressure as a positive prognostic indicator in deep sclerectomy

AIM

To study the possibility of using intraocular pressure (IOP) in the first postoperative day after sclerectomy as a prognostic indicator.

METHODS

Non-randomised prospective trial involving 105 eyes of 105 patients with medically uncontrolled primary and secondary open angle glaucoma. Visual acuity, IOP, and slit lamp examinations were performed before and after surgery at 1 and 7 days, and 1, 3, 6, 9, 12, 18, 24, 30, 36, 48, 54, 60, and 66 months. Visual field examinations were repeated every 6 months. A split point on day 1 IOP of less than or equal to 5 mm Hg (61%) versus more than 5 mm Hg (39%) was used. The first postoperative day IOP was examined in relation to the need for subsequent Nd:YAG goniopuncture, the subsequent use of postoperative antiglaucoma medications, and as a stratification variable in the Kaplan-Meier analyses.

RESULTS

The mean follow up was 43.2 (SD 14.3) months. The mean preoperative IOP was 26.8 (SD 7.7) mm Hg; the mean postoperative IOP was 5.1 (3.3) mm Hg at day 1 and 11.8 (3.1) mm Hg at month 60. Patients with IOP </=5 mm Hg had significantly fewer Nd:YAG goniopunctures (p = 0.0478). A significant (log rank test 0.0122) improvement for those with IOP </=5 mm Hg in terms of survival was detected using the most stringent criterion (IOP </=15 mm Hg with no medications). For patients with first postoperative day IOP </=5 mm Hg, the median time to failure was 24 months (95% CI: 12 to 30), but for those with an IOP >5 mm Hg, the median time to failure was only 6 months (CI 2 to 9). No significant difference in postoperative antiglaucoma medications was observed.

CONCLUSION

First postoperative day IOP can be considered to be a significant prognostic indicator in deep sclerectomy.

New insights into the pathophysiology of ovarian hyperstimulation syndrome. What makes the difference between spontaneous and iatrogenic syndrome?

The recent identification of mutations in the FSH receptor gene, which display an increased sensitivity to hCG and are responsible for the development of spontaneous ovarian hyperstimulation syndrome (OHSS), provides for the first time the molecular basis for the physiopathology of spontaneous OHSS. Based on these recent findings, this paper underlines the differences between spontaneous and iatrogenic OHSS and proposes a model to account for the different chronology between the two forms of the syndrome. In the iatrogenic form, the follicular recruitment and enlargement occur during ovarian stimulation with exogenous FSH, while in the spontaneous form, the follicular recruitment occurs later through the stimulation of the FSH receptor by pregnancy-derived hCG. In both forms, massive luteinization of enlarged stimulated ovaries ensues, inducing the release of vasoactive mediators, leading to the development of the symptoms of OHSS.

Tyrosine sulfation is required for agonist recognition by glycoprotein hormone receptors

The glycoprotein hormone receptors (thyrotrophin receptor, TSHr; luteinizing hormone/chorionic gonadotrophin receptor, LH/CGr; follicle-stimulating hormone receptor, FSHr) constitute a subfamily of rhodopsin-like G protein-coupled receptors (GPCRs) with a long N-terminal extracellular extension responsible for high-affinity hormone binding. These ectodomains contain two cysteine clusters flanking nine leucine-rich repeats (LRR), a motif found in several protein families involved in protein-protein interactions. Similar to the situation described recently in CCR5, we demonstrate here that the TSHr, as it is present at the cell surface, is sulfated on tyrosines in a motif located downstream of the C-terminal cysteine cluster. Sulfation of one of the two tyrosines in the motif is mandatory for high-affinity binding of TSH and activation of the receptor. Site-directed mutagenesis experiments indicate that the motif, which is conserved in all members of the glycoprotein hormone receptor family, seems to play a similar role in the LH/CG and FSH receptors.

An examination of different Percoll density gradients and magnetic activated cell sorting (MACS) for the enrichment of fetal erythroblasts from maternal blood

OBJECTIVE

To increase the yield of fetal erythroblasts from the blood of pregnant women by optimising and simplifying the enrichment procedure.

METHODS

By using an experimental system whereby cord blood was mixed with normal adult blood, we evaluated the recovery of fetal erythroblasts using different single or double percoll density gradients with or without subsequent enrichment by Magnetic Activated Cell Sorting (MACS).

RESULTS

The recovery of erythroblasts on single density gradients increased from 3%-68% of the input erythroblasts with an increase in the density of percoll from 1075 g/l-1098 g/l. Although the use of a double density gradient did eliminate most lymphocytes, it was accompanied by a significant loss of erythroblasts. The combination with MACS enrichment, however, lead to a almost 200 fold increase in the purity of erythroblasts.

CONCLUSIONS

Erythroblasts are preferentially retained by higher density gradients. To enhance their purity a subsequent more specific enrichment step, such as MACS is advisable.

Microstaging of pT1 transitional cell carcinoma of the bladder: identification of subgroups with distinct risks of progression

OBJECTIVES

To evaluate microstaging by means of quantifying the depth of invasion of the subepithelial connective tissue in pT1 transitional cell carcinoma (TCC) of the bladder for its additional prognostic value with respect to disease recurrence and progression.

METHODS

We reviewed the pathologic findings of a consecutive series of 124 patients with pT1 tumors entered in a prospective randomized multicenter trial comparing mitomycin C and bacillus Calmette-Guérin treatment, with at least 3 years of follow-up and clinical outcome hidden from reviewers. The depth of invasion was established by identifying submucosal tumor invasion up to, in, or beyond the muscularis mucosae or vascular plexus and classified as pT1a, pT1b, or pT1c, respectively. In addition to tumor grade, the presence of carcinoma in situ (CIS) near the primary tumor or in biopsy specimens taken from abnormal looking mucosa was taken into account. The risks of recurrence and progression were calculated using Kaplan-Meier curves and modeled with proportional hazard models.

RESULTS

pT1 subclassification was possible in more than 90% of the specimens. The 3-year risk of recurrence was not different in any of the subgroups. By contrast, the Kaplan-Meier 3-year risk for progression was 6%, 33%, and 55% for pT1a, pT1b (hazard ratio [HR] 5.51), and pT1c (HR 12.35) tumors, respectively (log-rank test P < 0.001). The Kaplan-Meier 3-year risk of progression was 9% versus 39% (HR 5.62) for the absence or presence of CIS in the tumor (P=0.001) and 8% versus 49% (HR 6.72) for CIS in biopsy specimens (P < 0.001). Tumor grade had no statistically significant prognostic value with respect to progression, nor had tumor volume or multifocality. The combination of the parameters (pT1c and CIS) increased the risk of progression by a factor of 27 (P < 0.0001) compared with the absence of pT1c and CIS.

CONCLUSIONS

These data show that the extent of lamina propria invasion (pT1a, pT1b, pT1c) is a clinically relevant prognostic factor for progression of pT1 TCC of the bladder. With the combination of this pT1 subclassification and the presence of CIS subgroups, distinct risks of progression can be identified that may give additional information for follow-up and treatment policies.

On the presence of inulin and oligofructose as natural ingredients in the western diet

The classic definitions of inulin and oligofructose are constructively criticized. It is observed that inulin cannot unequivocally be described as a polydisperse 1-kestose-based (GFn) beta (2-->1) linear fructan chain, but that inulin always contains small amounts of Fm and branched molecules. This review article describes the presence of inulin and oligofructose in common foodstuffs. Historical data on human consumption add an extra dimension. Modern analytical techniques (HPLC, LGC, HPAEC-PAD) are used to check the variety of data mentioned in the literature throughout the past century. Methods to determine inulin and oligofructose in natural foodstuffs (cereals, fruit, and vegetables) are optimized and used to determine the loss of inulin during storage and during preparation of the food. These findings allow quantification of the amount of inulin and oligofructose in the average daily western diet. The daily per capita intake is estimated to range from 1 to 10 g, depending on geographic, demographic, and other related parameters (age, sex, season, etc.). Inulin and oligofructose are not measured by classic methods of dietary fiber analysis and consequently are often not mentioned in food tables. Their significant contribution (1 to 10 g/d/per capita) to the dietary fiber fraction (recommended at 25 g/d/per capita) is not taken into account in any nutritional recommendations. In view of this, inulin and oligofructose deserve more attention, both in food composition tables and in diet or nutrition studies.

Psychometric characteristics and validity of the Dutch adaptation of the Buss-Durkee Hostility Inventory (the BDHI-D)

Data are presented on the factorial structure, internal consistency, and validity of the Dutch adaptation of the Buss-Durkee Hostility Inventory (the BDHI-D). Factor analyses of the responses of 463 subjects revealed two scales measuring Overt Aggression and Covert Aggression. The reliability of both subscales is good. Concordance with other self-report measures reveals satisfactory convergent and divergent validity.

Rapid kinetics of glucose uptake in Saccharomyces cerevisiae

In a multiple deletion mutant hxt1deltahxt2deltahxt3delta hxt4deltasnf3delta of Saccharomyces cerevisiae growing on a 2% glucose, high-affinity glucose-uptake (low Km) was exhibited throughout growth on glucose in contrast to the wild-type, which exhibited the usual low-affinity to high-affinity transition as the glucose in the medium was consumed. Elevated levels of invertase activity throughout growth on glucose, in this mutant as compared to the wild-type, indicate that glucose repression may be impaired. However, in a mutant containing only the HXT2 gene (hxt1deltahxt3deltahxt4deltasnf3delta), invertase levels were similar to those in the wild-type. It is likely, therefore, that some of these putative glucose transporters, such as HXT2, also have regulatory roles in cellular metabolism. In triple hexose-kinase mutants, rapid (200-ms) measurements of initial glucose-uptake revealed high-affinity glucose uptake (Km approx. 2 mmol/L) while measurements on the slower 5-s scale clearly demonstrate that uptake is not linear over this longer period. These results suggest that this high-affinity component does not require a functional hexose-kinase.

Reversal of optic disc cupping and pallor in patients with ocular hypertension using timolol therapy

We studied the quantitative effects on optic disc cupping and pallor in a double-masked, prospective clinical trial in which patients were randomized to timolol and placebo groups.

Eating in combat: a survey of U.S. Marines

A survey of U.S. Marines was conducted in order to investigate the effect of combat, a highly stressful situation, on eating behavior. The results indicate that Marines reduced their food intake, especially during their first combat experience. The principle reason cited for reduced consumption during combat was the lack of time to eat and prepare food. However, fear was important in accounting for reduced consumption during the marines' initial exposure to combat. The results are consistent with other laboratory and survey findings that stress leads to a reduction in food intake.

Effect of head-out water immersion on response to exercise training

During spaceflight and head-out water immersion (WI) there is a cephalad shift in blood volume. We have recently shown that left ventricular end-diastolic dimension is significantly greater during moderate cycling exercise with WI compared with on land. The purpose of this study was to determine whether the cephalad shift in blood volume and accompanying increase in cardiac preload with WI alters the normal cardiovascular adaptations to aerobic exercise training. Nine middle-aged healthy men trained on cycle ergometers in water, nine trained on land, and four served as controls for 12 wk. Following training, both training groups showed similar increase (P less than 0.05) in stroke volume and similar decreases in heart rate (P less than 0.01) and blood pressure (P less than 0.05) at a given submaximal exercise O2 consumption (VO2). Maximal VO2 increased (P less than 0.01) similarly for both training groups. The control group did not demonstrate any significant changes in submaximal or maximal exercise responses. We conclude that the cephalad shift in blood volume with WI does not alter the normal cardiovascular adaptation to aerobic exercise training.

Evaluation of the Vitatron "AKES" modification for optimal use in routine enzyme analysis

The Vitatron has been used as designed by the manufacturer under routine laboratory conditions (Broughton, P.M.G., Buttolph, M.A., Gowenlock, A.H., Neill, D.W. and Sleutelberg, R.G. (1969) J. Clin. Pathol. 22, 278). We assessed the possibilities of the AKES with regard to determination of the activities of three enzymes: alanine transaminase (AIT), aspartate transaminase (AsT) and lactate dehydrogenase (LDH) in serum. Precision, accuracy, carry over and sample-diluent contamination were evaluated. This resulted in recommendations for optimal use in terms of capacity and precision, which were supported by computations on a mathematical model for measuring results.