36 Feasibility of Resistance Exercise to Failure at Different Loads in Frail and Healthy Older Adults?

Introduction

Resistance training (RT) is the most effective way to increase muscle mass and function in older adults both with/without sarcopenia/frailty. In younger adults, when RT is performed to muscle failure the load lifted does not mediate the magnitude of response, but there are no studies in older adults. We aimed to determine the feasibility of recruitment to a RT intervention working to muscle failure at different loads in frail and healthy older adults.

Methods

We performed an 8-week randomised feasibility trial of lower limb RT to volitional muscular failure, at high and low load. Participants were recruited via hospital outpatient clinics and newspaper advertisements. Outcomes included: frailty assessment (Fried criteria); muscle strength (maximum voluntary contraction/one-repetition maximum); functional abilities (Short Physical Performance Battery); safety/adverse events were recorded via a log, and patient experiences from focus groups.

Results

110 people were assessed for eligibility, and 58 randomised (frail n = 6, prefrail n = 20, robust n = 32) to either high (n = 30) or low load (n = 28) groups. Mean age of participants was 72 years (range 65–93), 36 were female, 22 male. Session attendance was 95% (high load) and 90.4% (low load). Most participants were recruited via advertisements. All participants reported feeling safe and reassured in the RT sessions. Two participants had a serious adverse event, one related to RT (hypotension) and several had adverse events (three intervention-related). Pain was reported at both loads (high n = 9, low n = 8) yet all completed. There were no differences (P > 0.05) in effects of RT outcome variables between low and high load groups.

Conclusion

In this feasibility trial the recruitment of frail patients via clinics was limited. Performing supervised RT to muscle failure in older adults was safe/acceptable and the load at which RT was performed did not influence its efficacy. Future research into the effectiveness of such RT is warranted.

The association between driving time and unhealthy lifestyles: a cross-sectional, general population study of 386 493 UK Biobank participants

BACKGROUND

Driving is a common type of sedentary behaviour; an independent risk factor for poor health. The study explores whether driving is also associated with other unhealthy lifestyle factors.

METHODS

In a cross-sectional study of UK Biobank participants, driving time was treated as an ordinal variable and other lifestyle factors dichotomized into low/high risk based on guidelines. The associations were explored using chi-square tests for trend and binary logistic regression.

RESULTS

Of the 386 493 participants who drove, 153 717 (39.8%) drove <1 h/day; 140 140 (36.3%) 1 h/day; 60 973 (15.8%) 2 h/day; and 31 663 (8.2%) ≥3 h/day. Following adjustment for potential confounders, driving ≥3 h/day was associated with being overweight/obese (OR = 1.74, 95% CI: 1.64-1.85), smoking (OR = 1.48, 95% CI: 1.37-1.63), insufficient sleep (1.70, 95% CI: 1.61-1.80), low fruit/vegetable intake (OR = 1.26, 95% CI: 1.18-1.35) and low physical activity (OR = 1.05, 95% CI: 1.00-1.11), with dose relationships for the first three, but was not associated with higher alcohol consumption (OR = 0.94, 95% CI: 0.87-1.02).

CONCLUSIONS

Sedentary behaviour, such as driving, is known to have an independent association with adverse health outcomes. It may have additional impact mediated through its effect on other aspects of lifestyle. People with long driving times are at higher risk and might benefit from targeted interventions.

Associations of dietary protein intake with bone mineral density: An observational study in 70,215 UK Biobank participants

PURPOSE

Adequate dietary protein intake is important for the maintenance of bone health; however, data in this area is ambiguous with some suggestion that high protein intake can have deleterious effects on bone health. The aim of the current study was to explore the associations of protein intake with bone mineral density (BMD).

METHODS

We used baseline data from the UK Biobank (participants aged 40-69 years) to examine the association of protein intake with BMD (measured by ultrasound). These associations were examined, in women (n = 39,066) and men (n = 31,149), after adjustment for socio-demographic and lifestyle confounders and co-morbidities.

RESULTS

Protein intake was positively and linearly associated with BMD in women (β-coefficient 0.010 [95% CI 0.005; 0.015, p < 0.0001]) and men (β-coefficient 0.008 [95% CI 0.000; 0.015, p = 0.044]); per 1.0 g/kg/day increment in protein intake, independently of socio-demographics, dietary factors and physical activity.

CONCLUSIONS

The current data have demonstrated that higher protein intakes are positively associated with BMD in both men and women. This indicates that higher protein intakes may be beneficial for both men and women.

Wastewater recycling in Antarctica: Performance assessment of an advanced water treatment plant in removing trace organic chemicals

The Australian Antarctic Division (AAD) operates Australia's Davis Station in the Antarctic. In 2005, Davis Station's wastewater treatment plant failed and since then untreated, macerated effluent has been discharged to the ocean. The objectives of this study were to determine whether an advanced water treatment plant (AWTP) commissioned by the AAD and featuring a multi-barrier process involving ozonation, ceramic microfiltration, biologically activated carbon filtration, reverse osmosis, ultraviolet disinfection and chlorination was capable of producing potable water and a non-toxic brine concentrate that can be discharged with minimal environmental impact. The AWTP was tested using water from a municipal wastewater treatment plant in Tasmania, Australia. We used spot water and passive sampling combined with two multi-residue chromatographic-mass spectrometric methods and a range of recombinant receptor-reporter gene bioassays to screen trace organic chemicals (TrOCs), toxicity and receptor activity in the Feed water, in the environmental discharge (reject water), and product water from the AWTP for six months during 2014-15, and then again for three months in 2016. Across the two surveys we unambiguously detected 109 different TrOCs in the feed water, 39 chemicals in the reject water, and 34 chemicals in the product water. Sample toxicity and receptor activity in the feed water samples was almost totally removed in both testing periods, confirming that the vast majority of the receptor active TrOCs were removed by the treatment process. All the NDMA entering the AWTP in the feed and/or produced in the plant (typically < 50 ng/L), was retained into the reject water with no NDMA observed in the product water. In conclusion, the AWTP was working to design, and releases of TrOCs at the concentrations observed in this study would be unlikely cause adverse effects on populations of aquatic organisms in the receiving environment or users of the potable product water.

Homoarginine and inhibition of human arginase activity: kinetic characterization and biological relevance

The inhibition of arginase, resulting in higher arginine (ARG) availability for nitric oxide synthesis, may account for the putative protective effect of homoarginine (HOMOARG) against atherosclerosis and cardiovascular disease. However, uncertainty exists regarding the significance of HOMOARG-induced arginase inhibition in vivo. A novel UPLC-MS method, measuring the conversion of ARG to ornithine (ORN), was developed to determine arginase 1 and arginase 2 inhibition by HOMOARG, lysine (LYS), proline (PRO), agmatine (AG), asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and NG-Monomethyl-L-arginine (L-NMMA). Plasma HOMOARG, ARG and ORN concentrations were further measured in 50 healthy older adults >65 years (27 males and 23 females). HOMOARG inhibited arginase 1 with IC50 and Ki values of 8.14 ± 0.52 mM and 6.1 ± 0.50 mM, and arginase 2 with IC50 and Ki values of 2.52 ± 0.01 mM and 1.73 ± 0.10 mM, respectively. Both arginase isoforms retained 90% activity vs. control when physiological HOMOARG concentrations (1-10 µM) were used. In partial correlation analysis, plasma HOMOARG was not associated with ARG (P = 0.38) or ARG/ORN ratio (P = 0.73) in older adults. Our results suggest that arginase inhibition is unlikely to play a significant role in the reported cardio-protective effects of HOMOARG.

Sex Differences in the Associations between L-Arginine Pathway Metabolites, Skeletal Muscle Mass and Function, and their Responses to Resistance Exercise, in Old Age

OBJECTIVES

The current study was designed to explore the associations between L-arginine metabolites and muscle mass and function in old age, which are largely unknown.

DESIGN

The study used a randomised, double-blind, placebo-controlled design.

SETTING

The study was carried out in a laboratory setting.

PARTICIPANTS

50 healthy older adults [median age 70 years (IQR 67-73); 27 males].

INTERVENTION

Participants undertook an 18-week resistance exercise program, and a nutritional intervention (fish oil vs. placebo).

MEASUREMENTS

Serum homoarginine, ornithine, citrulline, asymmetric dimethylarginine (ADMA), NG-monomethyl-L-arginine (L-NMMA), and symmetric dimethylarginine (SDMA), maximal voluntary contraction (MVC) and isokinetic torque of the knee extensors at 30° s-1 (MIT), muscle cross sectional area (MCSA) and quality (MQ) were measured at baseline and after the intervention.

RESULTS

No significant exercise-induced changes were observed in metabolite concentrations. There were significant sex differences in the associations between metabolites and muscle parameters. After adjusting for age, glomerular filtration rate and fish oil intervention, citrulline (P=0.002) and ornithine (P=0.022) were negatively associated with MCSA at baseline in males but not females. However, baseline citrulline was negatively correlated with exercise-induced changes in MVC (P=0.043) and MQ (P=0.026) amongst females. Furthermore, amongst males, baseline homoarginine was positively associated with exercise-induced changes in MVC (P=0.026), ADMA was negatively associated with changes in MIT (P=0.026), L-NMMA (p=0.048) and ornithine (P<0.001) were both positively associated with changes in MCSA, and ornithine was negatively associated with changes in MQ (P=0.039).

CONCLUSION

Therefore, barring citrulline, there are significant sex differences in the associations between L-arginine metabolites and muscle mass and function in healthy older adults. These metabolites might enhance sarcopenia risk stratification, and the success of exercise programs, in old age.

Dietary fat and total energy intake modifies the association of genetic profile risk score on obesity: evidence from 48 170 UK Biobank participants

BACKGROUND

Obesity is a multifactorial condition influenced by both genetics and lifestyle. The aim of this study was to investigate whether the association between a validated genetic profile risk score for obesity (GPRS-obesity) and body mass index (BMI) or waist circumference (WC) was modified by macronutrient intake in a large general population study.

METHODS

This study included cross-sectional data from 48 170 white European adults, aged 37-73 years, participating in the UK Biobank. Interactions between GPRS-obesity and macronutrient intake (including total energy, protein, fat, carbohydrate and dietary fibre intake) and its effects on BMI and WC were investigated.

RESULTS

The 93-single-nucleotide polymorphism (SNP) GPRS was associated with a higher BMI (β: 0.57 kg m^-2 per s.d. increase in GPRS (95% confidence interval: 0.53-0.60); P=1.9 × 10^-183) independent of major confounding factors. There was a significant interaction between GPRS and total fat intake (P_{(interaction)}=0.007). Among high-fat-intake individuals, BMI was higher by 0.60 (0.52, 0.67) kg m^-2 per s.d. increase in GPRS-obesity; the change in BMI with GPRS was lower among low-fat-intake individuals (β: 0.50 (0.44, 0.57) kg m^-2). Significant interactions with similar patterns were observed for saturated fat intake (high β: 0.66 (0.59, 0.73) versus low β: 0.49 (0.42, 0.55) kg m^-2, P_{(interaction)}=2 × 10^-4) and for total energy intake (high β: 0.58 (0.51, 0.64) versus low β: 0.49 (0.42, 0.56) kg m^-2, P_{(interaction)}=0.019), but not for protein intake, carbohydrate intake and fibre intake (P_{(interaction)} >0.05). The findings were broadly similar using WC as the outcome.

CONCLUSIONS

These data suggest that the benefits of reducing the intake of fats and total energy intake may be more important in individuals with high genetic risk for obesity.

The relationship between vitamin D status and muscle strength in young healthy adults from sunny climate countries currently living in the northeast of Scotland

The current study examined the relationship between vitamin D status and muscle strength in young healthy adults: residents (>6 months) and newcomers (0-3 months), originally from sunny climate countries but currently living in the northeast of Scotland. Our longitudinal data found a positive, albeit small, relationship between vitamin D status and knee extensor isometric strength.

INTRODUCTION

Vitamin D has been suggested to play a role in muscle health and function, but studies so far have been primarily in older populations for falls prevention and subsequent risk of fractures.

METHODS

Vitamin D status was assessed in a healthy young adults from sunny climate countries (n = 71, aged 19-42 years) with 56% seen within 3 months of arriving in Aberdeen [newcomers; median (range) time living in the UK = 2 months (9-105 days)] and the remainder resident for >6 months [residents; 23 months (6-121 months)]. Participants attended visits every 3 months for 15 months. At each visit, fasted blood samples were collected for analysis of serum 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), carboxy-terminal collagen crosslinks (CTX) and N-terminal propeptide of type I collagen (P1NP). Maximal voluntary contractions (MVC) were performed for grip strength (both arms) and for maximal isometric strength of the knee extensors (right knee).

RESULTS

There were small seasonal variations in 25(OH)D concentrations within the newcomers and residents, but no seasonal variation in bone turnover markers. There was a positive, albeit small, association between 25(OH)D and knee extensor maximal isometric strength. Mixed modelling predicted that for each 1 nmol/L increase in 25(OH)D, peak torque would increase by 1 Nm (p = 0.04).

CONCLUSIONS

This study suggests that vitamin D may be important for muscle health in young adults migrating from sunnier climates to high latitudes, yet the potential effect is small.

Fish Oils and their Potential in the Treatment of Sarcopenia

We are living in an "ageing society" meaning that there will be an increase in the incidence of age related health problems. One issue consistently observed in ageing is for muscle mass and strength to be reduced, a condition termed sarcopenia. The consequences of these changes are numerous and include a reduction in quality of life and an increased risk of falls. The mechanisms underlying sarcopenia remain to be elucidated but include an anabolic resistance to both nutrients and exercise and so the search for strategies to overcome this resistance is of great importance. There are several nutritional strategies purported to be useful in the treatment of sarcopenia and in recent years the n-3 PUFAs found in fish oil have been of increasing interest. This review will discuss the main nutritional interventions used in the treatment of sarcopenia with a focus on fish oils.

The Effect of Fish Oil, Vitamin D and Protein on URTI Incidence in Young Active People

Upper respiratory tract infections (URTI) are a frequent illness among athletes. We investigated the effect of a multi-nutrient supplement (vitamin D, fish oil and protein) on the occurrence of URTI in young active people. 42 young recreational athletes were randomly assigned to receive either supplementation (550 mg DHA, 550 mg EPA, 10 µg vitamin D3 and 8 g whey protein) or placebo for 16 weeks. Unstimulated saliva samples were collected by passive drool. Samples were analysed for IgA (sIgA) concentration and the secretion rate extrapolated by multiplying concentration by saliva flow rate. Physical activity levels and URTI incidence were monitored by questionnaire. Training status was not different between the 2 groups. There were no differences in the incidence, severity and duration of URTI. However the number of symptom days was lower in the supplemented compared to the control group (1.72±1.67 vs. 2.79±1.76; P<0.05). sIgA concentration and secretion rate did not differ between groups. This study demonstrates that 16 weeks of supplementation with fish oil, vitamin D and protein did not modify the incidence, severity and duration of URTI, although the total number of symptom days was reduced, in a healthy active population.

Detection and enumeration of Dekkera anomala in beer, cola, and cider using real-time PCR

AIMS

In this article, a quantitative real-time PCR assay for detection and enumeration of the spoilage yeast Dekkera anomala in beer, cola, apple cider, and brewing wort is presented as an improvement upon existing detection methods, which are very time-consuming and not always accurate.

METHODS AND RESULTS

  Primers were designed to exclude other organisms common in these beverages, and the assay was linear over 6 log units of cell concentrations. The addition of large amounts of non-target yeast DNA did not affect the efficiency of this assay. A standard curve of known DNA was established by plotting the C(t) values obtained from the QPCR against the log of plate counts on yeast peptone dextrose medium and unknowns showed exceptional correlation when tested against this standard curve. The assay was found to detect D. anomala at levels of 10-14 CFU ml⁻¹ in either cola or beer and at levels of 9·4-25·0 CFU ml⁻¹ in apple cider. The assay was also used to follow the growth of D. anomala in brewing wort.

CONCLUSIONS

The results indicate that real-time PCR is an effective tool for rapid, accurate detection and quantitation of D. anomala in beer, cola and apple cider.

SIGNIFICANCE AND IMPACT OF THE STUDY

This method gives a faster and more efficient technique to screen beer, cola, and cider samples and reduce spoilage by D. anomala. Faster screening may allow for significant reduction in economic loss because of reduced spoilage.

The significance of interactions between organic compounds on low pressure membrane fouling

Fouling of hollow fibre microfiltration and ultrafiltration membranes by solutions of pure organic compounds and mixtures of these compounds was studied with a backwashable membrane filtration apparatus. Small molecular weight compounds resulted in little fouling, while their polymeric analogues resulted in more severe fouling. Neutrally charged dextran resulted in minor, irreversible fouling, that was considered to be associated with blocking of small pores. Cationically charged chitosan produced gross fouling for which the extent of reversibility increased with salt addition. Anionically charged alginic acid resulted in gross irreversible fouling, except when being filtered by a hydrophilic membrane in the absence of calcium where a high degree of flux recovery was observed. Calcium addition to the alginic acid solutions resulted in gross fouling of all membranes and calcium bridging was considered to be responsible for this behaviour. Greater fouling occurred on the hydrophilic membrane compared to the hydrophobic membranes for bovine serum albumin (BSA) solutions, and this was considered to be due to physical blocking of pores, because addition of calcium resulted in lower flux declines. Addition of BSA and calcium to alginic acid solutions resulted in lower flux recoveries for the alginic acid system, consistent with the proposition that interactions between polysaccharide and other compounds are required for irreversible fouling on hydrophilic membranes.

Plasma IL-6, its soluble receptors and F2-isoprostanes at rest and during exercise in chronic fatigue syndrome

The aim of the current study was to investigate the levels of interleukin-6 (IL-6), its soluble receptors (sIL-6R and sgp130) and F(2)-isoprostanes, at rest and during exercise, in patients with chronic fatigue syndrome (CFS). Six male CFS patients and six healthy controls performed an incremental exercise test to exhaustion and a submaximal exercise bout to exhaustion. Blood samples taken in the submaximal test at rest, immediately post-exercise and 24 h post-exercise were analyzed for IL-6, sIL-6R, sgp130 and F(2)-isoprostanes. A further 33 CFS and 33 healthy control participants gave a resting blood sample for IL-6 and sIL-6R measurement. During the incremental exercise test only power output at the lactate threshold was lower (P<0.05) in the CFS group. F(2)-isoprostanes were higher (P<0.05) in CFS patients at rest and this difference persisted immediately and 24 h post-exercise. The exercise study found no differences in IL-6, sIL-6R or sgp130 at any time point between groups. In the larger resting group, there were no differences in IL-6 and sIL-6R between CFS and control groups. This investigation has demonstrated that patients with CFS do not have altered plasma levels of IL-6, sIL-6R or sgp130 either at rest or following exercise. F(2)-isoprostanes, however, were consistently higher in CFS patients.

Response of plasma IL-6 and its soluble receptors during submaximal exercise to fatigue in sedentary middle-aged men

The pleiotropic cytokine interleukin-6 (IL-6) has been demonstrated to increase during exercise. Little is known regarding the response of the soluble IL-6 receptors (sIL-6R and sgp130) during such exercise. The aim of the current study was to investigate the response of plasma IL-6, sIL-6R and sgp130 during fatiguing submaximal exercise in humans. Twelve participants underwent an incremental exercise test to exhaustion and one week later performed a submaximal exercise bout (96 +/- 6% lactate threshold) to volitional exhaustion. Blood samples taken at rest and immediately post exercise were analyzed for IL-6, sIL-6R and sgp130. IL-6 increased (P < 0.01) by 8.4 +/- 8.9 pg ml(-1) (75.7%) during the exercise period. sIL-6R and sgp130 also increased (P < 0.05) by 2.7 +/- 3.9 ng ml(-1) (9.6%) and 37.7 +/- 55.6 ng ml(-1) (9.6%), respectively. The current study is the first investigation to demonstrate that alongside IL-6, acute exercise stress results in an increase in both sIL-6R and sgp130.

Effect of membrane character and solution chemistry on microfiltration performance

To help understand and predict the role of natural organic matter (NOM) in the fouling of low-pressure membranes, experiments were carried out with an apparatus that incorporates automatic backwashing and long filtration runs. Three hollow fibre membranes of varying character were included in the study, and the filtration of two different surface waters was compared. The hydrophilic membrane had greater flux recovery after backwashing than the hydrophobic membranes, but the efficiency of backwashing decreased at extended filtration times. NOM concentration of these waters (7.9 and 9.1mg/L) had little effect on the flux of the membranes at extended filtration times, as backwashing of the membrane restored the flux to similar values regardless of the NOM concentration. The solution pH also had little effect at extended filtration times. The backwashing efficiency of the hydrophilic membrane was dramatically different for the two waters, and the presence of colloid NOM alone could not explain these differences. It is proposed that colloidal NOM forms a filter cake on the surface of the membranes and that small molecular weight organics that have an adsorption peak at 220nm but not 254nm were responsible for "gluing" the colloids to the membrane surface. Alum coagulation improved membrane performance in all instances, and this was suggested to be because coagulation reduced the concentration of "glue" that holds the organic colloids to the membrane surface.

Effect of NOM characteristics and membrane type on microfiltration performance

Efforts to understand and predict the role of different organic fractions in the fouling of low-pressure membranes are presented. Preliminary experiments with an experimental apparatus that incorporates automatic backwashing and filtration over several days has shown that microfiltration (MF) of the hydrophilic fractions leads to rapid flux decline and the formation of a cake or gel layer, while the hydrophobic fractions show a steady flux decline and no obvious formation of a gel or cake layer. The addition of calcium to the weakly hydrophobic acid (WHA) fraction led to the formation of a gel layer from associations between components of the WHA. The dominant foulants were found to be neutral and charged hydrophilic compounds, with hydrophobic and small pore size membranes being the most readily fouled. The findings suggest that surface analyses such as FTIR will preferentially identify hydrophilic compounds as the main foulants, as these components form a gel layer on the surface while the hydrophobic compounds adsorb within the membrane pores. Furthermore, coagulation pre-treatment is also likely to reduce fouling by reducing pore constriction rather than the formation of a gel layer, as coagulants remove the hydrophobic compounds to a large extent and very little of the hydrophilic neutral components.

Endolyn is a mucin-like type I membrane protein targeted to lysosomes by its cytoplasmic tail

Endolyn (endolyn-78) is a membrane protein found in lysosomal and endosomal compartments of mammalian cells. Unlike 'classical' lysosomal membrane proteins, such as lysosome-associated membrane protein (lamp)-1, it is also present in a subapical compartment in polarized WIF-B hepatocytes. The structural features that determine sorting of endolyn are unknown. We have identified a rat endolyn cDNA by expression screening. The cDNA encodes a ubiquitously expressed type I membrane protein with a short cytoplasmic tail of 13 amino acids and many putative sites for N- and O-linked glycosylation in the predicted luminal domain. Endolyn is closely related to two human mucin-like proteins, multi-glycosylated core protein (MGC)-24 and CD164 (MGC-24v), expressed in gastric carcinoma cells and bone marrow stromal and haematopoietic precursor cells respectively. The predicted transmembrane and cytoplasmic tail domains of endolyn, as well as parts of its luminal domain, also show some similarities with lamp-1 and lamp-2. Like these and other known lysosomal membrane proteins, endolyn contains a YXXO motif at the C-terminus of its cytoplasmic tail (where O is a bulky hydrophobic amino acid), but with no preceding glycine. Nonetheless, the last ten amino acids of this tail, when transplanted on to human CD8, caused efficient targeting of the chimaeric protein to endosomes and lysosomes in transfected normal rat kidney cells.

Cell polarization is required for ricin sensitivity in a Caco-2 cell line selected for ricin resistance

It has been proposed that killing of mammalian cells by ricin requires efficient endocytic delivery to the trans-Golgi network (TGN) prior to retrograde transport to the endoplasmic reticulum and entry to the cytosol. In polarized epithelial cells, an efficient membrane-traffic pathway to the TGN is present from the basolateral but not the apical plasma-membrane domain. Thus one can hypothesize that a ricin-resistant phenotype might be demonstrated by polarized cells that fail to differentiate and thus fail to develop an efficient membrane-traffic pathway from the basolateral plasma membrane to the TGN. We have isolated and studied a ricin-resistant Caco-2 cell clone (Caco-2-RCAr clone 2) which, when grown on plastic, was deficient in differentiation, measured by the development of polarized-cell-surface marker enzymes. The deficiency in differentiation was partially reversed, and ricin sensitivity was restored, when the cells were grown on filter supports. Our data provide the first evidence of a ricin-resistant cell line where resistance is due to the lack of development of polarized cell surfaces. The observed ricin resistance is consistent with the requirement that ricin is delivered to the TGN before its A chain enters the cytosol to mediate cell killing.

Goblet-cell mucinous epithelium lining the endometrium and endocervix: evidence of metastasis from an appendiceal primary tumor through the use of cytokeratin-7 and -20 immunostains

Differential staining with cytokeratin (CK)-7 and CK-20, two members of a complex family of proteins in human epithelial cells, proved critical in showing that the extremely well-differentiated goblet-cell (intestinal) mucinous epithelium lining the surface of the endometrium and endocervix in two patients and the fallopian tube in one was identical to that of the coincident appendiceal neoplasms. One of these patients also had a large ovarian tumor that grossly and microscopically resembled a mucinous cystadenoma of borderline malignancy and would have been considered primary except for the CK stains (CK-20 positive and CK-7 negative), which suggested metastasis from the appendix, presumably by a transtubal route.

Fusion of lysosomes with late endosomes produces a hybrid organelle of intermediate density and is NSF dependent

Using a cell-free content mixing assay containing rat liver endosomes and lysosomes in the presence of pig brain cytosol, we demonstrated that after incubation at 37 degrees C, late endosome-lysosome hybrid organelles were formed, which could be isolated by density gradient centrifugation. ImmunoEM showed that the hybrids contained both an endocytosed marker and a lysosomal enzyme. Formation of the hybrid organelles appeared not to require vesicular transport between late endosomes and lysosomes but occurred as a result of direct fusion. Hybrid organelles with similar properties were isolated directly from rat liver homogenates and thus were not an artifact of cell-free incubations. Direct fusion between late endosomes and lysosomes was an N-ethylmaleimide-sensitive factor-dependent event and was inhibited by GDP-dissociation inhibitor, indicating a requirement for a rab protein. We suggest that in cells, delivery of endocytosed ligands to an organelle where proteolytic digestion occurs is mediated by direct fusion of late endosomes with lysosomes. The consequences of this fusion to the maintenance and function of lysosomes are discussed.

Lysosomes can fuse with a late endosomal compartment in a cell-free system from rat liver

The passage of pulse doses of asialoglycoproteins through the endosomal compartments of rat liver hepatocytes was studied by subcellular fractionation and EM. The kinetics of disappearance of radiolabeled asialofetuin from light endosomes prepared on Ficoll gradients were the same as the kinetics of disappearance of asialoorosomucoid-horse radish peroxidase reaction products from intracellular membrane-bound structures in the blood sinusoidal regions of hepatocytes. The light endosomes were therefore identifiable as being derived from the peripheral early endosome compartment. In contrast, the labeling of dense endosomes from the middle of the Ficoll gradient correlated with EM showing large numbers of reaction product-containing structures in the nonsinusoidal parts of the hepatocyte. In cell-free, postmitochondrial supernatants, we have previously observed that dense endosomes, but not light endosomes, interact with lysosomes. Cell-free interaction between isolated dense endosomes and lysosomes has now been reconstituted and analyzed in three ways: by transfer of radiolabeled ligand from endosomal to lysosomal densities, by a fluorescence dequenching assay which can indicate membrane fusion, and by measurement of content mixing. Maximum transfer of radiolabel to lysosomal densities required ATP and GTP plus cytosolic components, including N-ethylmaleimide-sensitive factor(s). Dense endosomes incubated in the absence of added lysosomes did not mature into vesicles of lysosomal density. Content mixing, and hence fusion, between endosomes and lysosomes was maximal in the presence of cytosol and ATP and also showed inhibition by N-ethyl-maleimide. Thus, we have demonstrated that a fusion step is involved in the transfer of radiolabeled ligand from an isolated endosome fraction derived from the nonsinusoidal regions of the hepatocyte to preexisting lysosomes in a cell-free system.

Solubilization and purification of a putative quisqualate-sensitive glutamate receptor from crustacean muscle

Two high-affinity glutamate-binding proteins have been solubilized and purified from crustacean muscle membranes. L-[3H]Glutamate binding to intact membranes gave IC50 values (concn. giving 50% inhibition) of 0.35 microM for glutamate. 9.0 microM for quisqualate and 36.2 microM for ibotenic acid. Kainate, domoate, N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, D-glutamate and L-aspartate were poor inhibitors of glutamate binding. The two protein were purified approx. 600-fold from muscle membranes by use of concanavalin A and gel-filtration column chromatography. One protein showed an apparent Stokes radius of 5.4 nm, as determined by gel filtration, with a subunit of Mr 74000 as shown by SDS/polyacrylamide-gel electrophoresis. Analysis of glutamate binding to this protein revealed a KD of 2.4 microM and a Bmax, of 15.5 nmol/mg, and a k1 for quisqualate inhibition of glutamate binding of 1.0 microM. The second protein was eluted anomalously from the gel-filtration column and showed a subunit of Mr 65000 on SDS/polyacrylamide gels. Glutamate binding to this protein showed a KD of 1.3 microM and a Bmax, of 14.5 nmol/mg, and was only slightly sensitive to the presence of quisqualate (Ki = 0.8 mM). Glutamate binding to both proteins was insensitive to kainate. It is concluded that the Mr-74000 protein is a prime candidate for the quisqualate-sensitive receptor of the crustacean neuromuscular junction.

Isolation of nerve terminals from crustacean muscle

A method for the isolation of gamma-aminobutyric acidergic (GABAergic) and glutamatergic terminals from crustacean muscle was developed, using differential centrifugation and sucrose density gradient centrifugation. Individual fractions were assessed using a variety of markers. One fraction was isolated which showed 40-fold purification of glutamate decarboxylase with a yield of 12%. This fraction was enriched in GABA, glutamate, glutamate dehydrogenase, and 5'-nucleotidase, but not in NADPH cytochrome c reductase. This fraction possessed an uptake system for GABA and glutamate with apparent kinetic constants of Km = 50 microM, Vmax = 250 pmol/min/mg of protein and Km = 183 microM, Vmax = 219 pmol/min/mg of protein, respectively. Electron microscopy showed nerve terminal profiles and a heterogeneous population of membrane vesicles. This fraction contained 3.4 nmol ATP/mg of protein which was stable for 30 min at 12 degrees C, and was also able to synthesise ATP from exogenous adenosine. The terminals released labelled GABA and glutamate in a Ca2+-dependent fashion on depolarisation. No release of ATP was detected. It is concluded that viable nerve terminals have been isolated which could be used as model systems for the study of GABAergic and glutamatergic neurochemistry.

Changes in the ability of malonyl-CoA to inhibit carnitine palmitoyltransferase I activity and to bind to rat liver mitochondria during incubation in vitro. Differences in binding at 0 degree C and 37 degrees C with a fixed concentration of malonyl-CoA

Time courses for inhibition of carnitine palmitoyltransferase (CPT) I activity in, and [14C]malonyl-CoA binding to, liver mitochondria from fed or 48 h-starved rats were obtained at 37 degrees C by using identical incubation conditions and a fixed concentration of malonyl-CoA (3.5 microM), which represents the middle of the physiological range observed previously [Zammit (1981) Biochem. J. 198, 75-83] Incubation of mitochondria in the absence of malonyl-CoA resulted in a time-dependent decrease in the ability of the metabolite instantaneously to inhibit CPT I and to bind to the mitochondria. Both degree of inhibition and binding were restored in parallel over a period of 6-8 min on subsequent addition of malonyl-CoA to the incubation medium. However, the increased inhibition of CPT I activity on addition of mitochondria directly to malonyl-CoA-containing medium was not accompanied by an increase in the amount of [14C]malonyl-CoA bound to mitochondria at 37 degrees C. Time courses for binding of [14C]malonyl-CoA performed at 0 degree C were different from those obtained at 37 degrees C. There was little loss of ability of [14C]malonyl-CoA to bind to mitochondria on incubation in the absence of the metabolite, but there was a time-dependent increase in binding on addition of mitochondria to malonyl-CoA-containing medium. It is suggested that these temperature-dependent differences between the time courses obtained may be due to the occurrence of different changes at 37 degrees C and at 0 degree C in the relative contributions of different components (with different affinities) to the binding observed at 3.5 microM-malonyl-CoA. Evidence for multi-component binding was obtained in the form of strongly curvilinear Scatchard plots for instantaneous (5s) binding of malonyl-CoA to mitochondria. Such multi-component binding would be expected from previous results on the different affinities of CPT I for malonyl-CoA with respect to inhibition [Zammit (1984) Biochem. J. 218, 379-386]. Mitochondria obtained from starved rats showed qualitatively the same time courses as those described above, with notable quantitative differences with respect both to the absolute extents of CPT I inhibition and [14C]malonyl-CoA binding achieved as well as to the time taken to attain them.

Cellular angiomas of infancy: an ultrastructural study of two cases

Vascular tumors in infants may be clinically disfiguring, requiring surgical intervention. Some of these lesions are histopathologically worrisome, due to increased cellularity and mitotic activity. The interpretation of these lesions is hampered by a surfeit of terminology, although, regardless of the diagnostic name, they are clinically benign. Two such cellular angiomas are reported, one typical and one unusual case. Electron microscopy of both cases demonstrated a heterogeneous cellular composition, primarily endothelial cells and pericytes. In those light microscopic areas of diffuse growth, primitive vascular structures were resolved. Electron microscopy may be diagnostically useful in supporting the light microscopic impression of a vascular tumor.

Oncocytic neoplasms of salivary glands: a report of fifteen cases including two malignant oncocytomas

Fifteen oncocytic (oxyphilic granular cell) neoplasms of the salivary glands collected from three large university medical centers are presented. The histologic and ultrastructural criteria that characterize oncocytes are presented and electron micrographs of two of our cases are discussed. Included in the series are 10 benign oncocytomas, two malignant oncocytomas and three benign, oncocytic pleomorphic adenomas. The clinical and pathologic features of benign oncocytomas are reviewed, with special attention to the variety of gross and microscopic changes present. The literature on malignant oncocytomas is critically reviewed, diagnostic criteria are evaluated, and a unique case is discussed in detail. Reference is made to a group of neoplasms that we designate as benign locally aggressive oncocytomas. The problem of differential diagnosis between oncocytoma and bening, oncocytic pleomorphic adenoma is considered.

Lymphangiomyomatosis: report of a case with ureteral involvement and chyluria

A 54-year-old woman, presenting with chyluria and progressive dyspnea, is reported. Necropsy revealed co-existent lymphangiomyomatosis and pneumoconiosis in the lungs. Retroperitoneal lymphangiomyomas surrounded the distal ureters, and cystoscopy revealed pyelolymphatic backflow into renal lymphatic sinuses. The finding of chyluria with atypical smooth muscle hyperplasia within the ureters is extremely rare. Previously reported cases of lymphangiomyomatosis are discussed and compared with our own. Electron micrographs of involved lymph nodes are presented and the findings briefly evaluated.