Trainee Knowledge and Perceptions of Less Than Full Time Training

Background Less than full-time (LTFT) training in Ireland is still unusual. Our aim was to identify perceived barriers to LTFT training amongst paediatric trainees and make recommendations to improve knowledge, uptake, and experience of LTFT training. Methods An email questionnaire was disseminated to RCPI paediatric trainees to assess current awareness of and perceptions of barriers to LTFT training. Results 218 questionnaires were distributed, 59 (29%) responded of whom 50 (85%) were female. 17 planned to apply for LTFT training. Seven had no knowledge of LTFT training. The perceived barriers with the highest rankings (% respondents deeming highest possible relevance) were: LTFT post availability (49%), potential impact on career progression (51%), and availability of only 0.5 whole time equivalency (WTE) - i.e. 19.5 hours/week (54%). Trainees noted lack of flexibility, including availability of the scheme only from July to July, restriction to maximum 2 years. Trainees felt applications would be rejected if they were not a parent. Some reported perceptions from teams that LTFT trainees are less committed and that trainees can find it difficult to integrate. Discussion Training options including >0.5WTE posts should be made available to all trainees, and a cultural shift within training bodies and with trainers should be encouraged to recognise LTFT training as an acceptable pathway for all trainees.

Reduced care burden and improved quality of life in African American family caregivers: Positive impact of personalized assistive technology

BACKGROUND

African Americans living with dementia are considered less likely to seek formal institutionalized elder care and more likely to be managed in the home by family-member caregivers. Assistive technologies (the use of smart visual devices like tablets and phones) can be used effectively to guide memory-impaired individuals with a sequence of pictures showing steps to complete activities of daily living, e.g., bathing, toileting, dressing. Assistive technology so far has not been generally embraced in African American communities.

OBJECTIVES

Determine, if African American family caregivers, given the opportunity, would embrace the use of assistive technology and if they would perceive its use beneficial.

METHODS

We assessed a group of eight family caregivers' overall care-burden scores, and their user-satisfaction scores after using assistive technology for three months.

RESULTS

We found significant reduction in caregiver burden, positive changes in behavior and emotion scores, and high ratings on user satisfaction.

CONCLUSIONS

The findings reported here comprise the first systematic study of the use of assistive technology by caregivers in an underserved population. They set the stage for exploring meaningful strategies and variables that will better engage underserved populations to take advantage of assistive technologies available in healthcare.

Feasibility of personalized visual mapping assistive technology to improve functional ability in persons with dementia

Background

Mobile health (mHealth) apps using novel visual mapping assistive technology can allow users to develop personalized maps that aid people living with cognitive impairment in the recall of steps needed to independently complete activities of daily living (ADLs), such as bathing, toileting, and dressing.

Objective

This study aims to determine the feasibility and preliminary impact of an mHealth assistive technology app providing guidance to aid individuals living with cognitive impairment in the recall of steps to independently complete ADLs.

Methods

A total of 14 Veterans (mean age 65 SD 9.5 years; 14/14, 100% male; 10/14, 71.4% Black) and 8 non-Veterans (mean age 78, SD 10.3 years; 5/8, 62.5% male; 8/8, 100% Black) were recruited and enrolled from the Department of Veterans Affairs (VA) and non-VA cognitive care clinics. A visual mapping software program, MapHabit, was used to generate a series of personalized visual map templates focused on ADLs created within the MapHabit app. The visual maps were accessed through a tablet device. A 19-item exit questionnaire was administered to the participants to assess perceived improvement in their functional ability after using the MapHabit system for 3 months.

Results

A total of 13 (93%) VA clinic participants and 8 (100%) non-VA clinic participants completed the 3-month study. Baseline cognitive testing indicated impaired to significantly impaired cognitive function. After 3 months of using the MapHabit system, VA clinic participants reported perceived improvement in social engagement (P=.01) and performance of ADLs (P=.05) compared to the baseline, whereas non-VA clinic participants reported improvements in the performance of ADLs (P=.02), mood (P=.04), social engagement (P=.02), and memory (P=.02). All study participants reported they would recommend the MapHabit system to a colleague, and 85% (11/14) of VA and 100% (8/8) of non-VA clinic participants reported a willingness to participate in a future study.

Conclusions

Older VA and non-VA clinic participants with cognitive impairment were willing to use an mHealth app to assist with the completion of ADLs, and they reported positive preliminary effects. A larger study is warranted to assess the efficacy in the setting of a randomized controlled trial.

Foreign-Born Individuals with HIV in King County, WA: A Glimpse of the Future of HIV?

To better understand country of birth-related shifts in the demography of people newly diagnosed with HIV infection, we compared demographic and clinical characteristics of foreign-born and U.S.-born residents of King County, WA diagnosed with HIV from 2006 to 2015. The proportion of cases that were foreign-born increased from 23 to 34% during this time. Most foreign-born cases were born in Africa (34%), Latin America (32%), Asia (22%), or Europe (7%). Latin Americans and Asians were similar to U.S.-born individuals by HIV risk factor and gender, while Africans were more likely to be female and less often men who have sex with men. In 2015, approximately 15% of cases presumptively newly diagnosed in King County were foreign-born individuals who self-reported a pre-immigration HIV diagnosis. Increases in foreign-born individuals previously diagnosed out of country may lead to inaccuracy in the count of new diagnoses, including an over-estimate of community-acquired HIV in King County.

Long-term patterns and feeding sites of southern green stink bug (Hemiptera: Pentatomidae) in Hawaii macadamia orchards, and sampling for management decisions

Southern green stink bug (Nezara viridula, Hemiptera: Pentatomidae) is a pest of macadamia nuts, causing pitting to kernels by feeding. In spite of its pest status, many aspects of the ecology of this insect in macadamia orchards are poorly understood. This study analyzes long-term N. viridula damage to macadamia nuts and investigates the extent to which damage to nuts occurs in the tree canopy, prior to nut-drop. We show that there are distinct seasonal peaks in damage detected after harvest and that, over six years of data collection, mean damage levels were fairly low, albeit with spikes in damage levels recorded. Sampling nuts at peak harvest periods from different strata in the trees and from the ground showed that incidence of damaged nuts within the canopy was typically half as high as on the fallen nuts. Damage to fallen nuts may have occurred prior to nut-drop, and continued to accumulate after nut-drop. These results show that management of N. viridula within macadamia canopies, as opposed to only on fallen nuts, is important. A sampling procedure and predictive model for estimating late-season damage based on early-season damage samples is provided. The model uses January and March damage measurements (based on samples with set level of accuracy), mean temperature and month of the year for which damage is predicted. Early-season damage of 6-10% predicts late-season damage levels that should justify N. viridula suppression based on the nominal threshold (13% damage) used by kernel processors to reject nuts based on damage.

Perigraft air, fever, and leukocytosis after endovascular repair of abdominal aortic aneurysms

BACKGROUND

The postimplantation syndrome of fever and leukocytosis after endovascular repair of infrarenal aortic aneurysms has not been previously characterized and its etiology is not known.

METHODS

We studied the first 12 patients who underwent successful endovascular repair of infrarenal aortic aneurysms with Dacron-covered stent-grafts, as part of an ongoing phase II clinical trial. Sepsis syndrome evaluations (physical examination, urinalysis, chest radiograph, urine cultures, and blood cultures) were performed for all patients with postoperative temperature (T) greater than 101.4 degrees F. Computed tomography scans of the abdomen were performed, as part of the clinical protocol, on postoperative days 2 and 30.

RESULTS

Fever (T > 101.4 degrees F) was seen in 8 of 12 (67%) patients (P < 05). An additional 2 of 12 (17%) patients had low-grade fevers (100.3 degrees F, 100.6 degrees F). Only 2 of 12 (17%) patients remained afebrile postoperatively. Leukocytosis with counts over 11,000 white blood cells (WBC)/dL was observed in 7 of 12 (58%) patients (P < 05). Sepsis evaluations failed to identify any source of infection in 11 of 12 (97%) patients. Computed tomography scan evidence of perigraft air was noted in 8 of 12 (67%) patients. All patients were afebrile, had normal white blood cell counts, and were discharged within 1 week postoperatively. There has been no evidence of graft infection after 1 to 6 months of follow-up.

CONCLUSIONS

Fever and leukocytosis after stent-graft repair of aortic aneurysms does not represent evidence of systemic or graft infection and is not clearly related to nonspecific causes of postoperative fever and leukocytosis. Moreover, the finding of early postoperative perigraft air is not necessarily an indication of graft infection even when concurrently present with fever and leukocytosis.

Helicobacter pylori is killed by nitrite under acidic conditions

BACKGROUND

Due to the expression of urease, Helicobacter pylori is able to establish itself in the human stomach under acidic conditions. A novel host defence mechanism was recently proposed, suggesting that the formation of salivary nitrite in symbiosis with facultative anaerobic bacteria in the oropharynx, is aimed at enhancing the antimicrobial activity of gastric juice.

AIMS

To investigate whether the addition of nitrite in physiological concentrations influences the resistance of H pylori to acid.

METHODS

H pylori cultured from fresh gastric Biopsy specimens was exposed for 30 minutes to normal saline and to HCl/KCl buffer (0.2M) at pH 2 with urea (5 mM) added. The influence of potassium nitrite (50-1000 mumol/l) on bacterial survival was determined.

RESULTS

Addition of nitrite (1 mM) to acidic solutions (pH 2) resulted in complete kill of H pylori within 30 minutes exposure time whereas acid alone allowed the organism to survive (p < 0.001). The antimicrobial effect of nitrite at pH 2 against H pylori was dose dependent and complete kill of organisms occurred at concentrations > or = 500 mumol/l.

CONCLUSION

Acidified nitrite has anti-bacterial activity against H pylori. This should prompt further research into the effect of salivary nitrite on the survival of H pylori in the human stomach.

Protection against oral and gastrointestinal diseases: importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation

Over the last 20 years, dietary nitrate has been implicated in the formation of methemoglobin and carcinogenic nitrosamines in humans. This has led to restrictions of nitrate and nitrite levels in food and drinking water. However, there is no epidemiological evidence for an increased risk of gastric and intestinal cancer in population groups with high dietary vegetable or nitrate intake. A reevaluation of our currently very negative perception of dietary nitrates comes from recent research into the metabolism and enterosalivary circulation of nitrate in mammals. These studies showed that nitrate is converted to nitrite in the oral cavity that then "fuels" an important mammalian resistance mechanism against infectious diseases. Moreover, there is now evidence that the conversion of nitrate into oxides of nitrogen prevents the formation carcinogenic nitrosamines.

HLA alloantibodies and the mechanism of the antiglobulin-augmented lymphocytotoxicity procedure

HLA Class I alloantigens express multiple epitopes which can be defined serologically using human HLA alloantibodies (aAb). We have shown that the vast majority of HLA antisera exhibit the CYNAP phenomenon (complement-dependent cytotoxicity (CDC) negative, adsorption positive) which can be identified by conversion to direct CDC positive reactivity with the addition of an antihuman immunoglobulin (Ig) light chain (AHG) reagent. In this study, the immunochemical mechanisms responsible for the CYNAP phenomena and how AHG overrides CYNAP have been further characterized using affinity-purified HLA aAb, class-specific anti-IgH reagents and human C1q binding assays quantified by flow cytometry. We have found that CYNAP reactions are not the result of low affinity aAb or generally caused by non-complement fixing HLA aAb. Our experiments illustrate that only anti-human IgL AHG reagents can consistently augment CDC and override CYNAP; anti-IgH have not effective. Two noncompeting HLA aAb of different epitopic specificity or one aAb in conjunction with the AHG-augmenting reagent results in striking synergy with a 200 to 400% increase in binding of C1q. We conclude from these and other experiments detailed in this article that an IgM aAb or either two adjacent, noncompeting IgG HLA aAb bound to spatially distinct epitopes on a single HLA molecule or a monospecific IgG HLA aAb in concert with the AHG binding to this HLA aAb, is required for efficient (bivalent) C1q binding and initiation of C-mediated lympholysis. In contrast, the CYNAP phenomenon usually occurs because monospecific HLA aAb directed against a single epitope cannot effect high affinity, bivalent interaction with Clq and activate complement that would ultimately lead to cytolysis.

Nitrate-reducing bacteria on rat tongues

Nitrite-producing bacteria (NPB) were isolated from tongues of laboratory rats. The most commonly found nitrite-producing organism was Staphylococcus sciuri, followed by Staphylococcus intermedius, Pasteurella spp., and finally Streptococcus spp. Both morphometric quantification of bacteria on tongue sections and enumeration of culturable bacteria (CFU) showed an increase in the density of bacteria towards the posterior tongue. Up to 65% of bacteria were located in the deep clefts on the posterior tongue. The proportion of culturable NPB in the total culturable microbial population increased from 6% (10(5) CFU cm-2) on the anterior tongue to 65% (10(7) CFU cm-2) on the posterior tongue. Different species compositions of NPB were found on different tongue sections with S. intermedius populations decreasing and S. sciuri and Pasteurella populations increasing towards the posterior tongue. Nitrite production was sensitive to oxygen, and significant nitrite production was only detected on the posterior tongue where the majority of bacteria are situated in deep clefts in the tongue surface. This study suggests the importance of bacteria in nitrite production, from nitrate, on the tongue. Nitrite produced on the tongue may subsequently form nitric oxide in the acidic environment of the stomach. Because of the antimicrobial properties of nitric oxide, a key role for nitrate-reducing tongue bacteria in host animal defense against food-borne pathogens in proposed.

Chemical synthesis of nitric oxide in the stomach from dietary nitrate in humans

BACKGROUND/AIMS

It has been suggested that dietary nitrate, after concentration in the saliva and reduction to nitrite by tongue surface bacteria, is chemically reduced to nitric oxide (NO) in the acidic conditions of the stomach. This study aimed to quantify this in humans.

METHODS

Ten healthy fasting volunteers were studied twice, after oral administration of 2 mmol of potassium nitrate or potassium chloride. Plasma, salivary and gastric nitrate, salivary and gastric nitrite, and gastric headspace NO concentrations were measured over six hours.

RESULTS

On the control day the parameters measured varied little from basal values. Gastric nitrate concentration was 105.3 (13) mumol/l (mean (SEM), plasma nitrate concentration was 17.9 (2.4) mumol/l, salivary nitrate concentration 92.6 (31.6) mumol/l, and nitrite concentration 53.9 (22.8) mumol/l. Gastric nitrite concentrations were minimal (< 1 mumol/l). Gastric headspace gas NO concentration was 16.4 (5.8) parts per million (ppm). After nitrate ingestion, gastric nitrate peaked at 20 minutes at 3430 (832) mumol/l, plasma nitrate at 134 (7.2) mumol/l, salivary nitrate at 1516.7 (280.5) mumol/l, and salivary nitrite at 761.5 (187.7) mumol/l after 20-40 minutes. Gastric nitrite concentrations tended to be low, variable, and any rise was non-sustained. Gastric NO concentrations rose considerably from 14.8 (3.1) ppm to 89.4 (28.6) ppm (p < 0.0001) after 60 minutes. All parameters remained increased significantly for the duration of the study.

CONCLUSIONS

A very large and sustained increase in chemically derived gastric NO concentrations after an oral nitrate load was shown, which may be important both in host defence against swallowed pathogens and in gastric physiology.

MR microscopy of the arterial wall in an experimental model of atherosclerosis: preliminary results

PURPOSE

To obtain images of the arterial lumen and wall in a rabbit model of atherosclerosis with use of high-resolution magnetic resonance (MR) imaging to follow morphologic changes during the induction of atherosclerosis and, hence, develop a non-invasive tool to investigate restenosis.

MATERIALS AND METHODS

In vivo microscopic MR images of rabbit aorta were acquired after balloon injury. Measurements of wall and lumen diameter from MR images area were compared with measurements obtained from histologic and angiographic examination.

RESULTS

Injured rabbits exhibited an obvious thickening of the arterial wall, accompanied by an increased wall conspicuity, probably due to increases in T2. Quantitative MR morphometry corresponded well with morphologic measurements based on angiographic and histologic study.

CONCLUSIONS

MR implanted coil technology affords imaging of the arterial lumen and wall, allowing temporal assessment of the morphologic changes due to intimal hyperplasia after balloon dilation and may enable the evaluation of novel techniques to eliminate restenosis.

Nine episodes of CPD-associated peritonitis with vancomycin resistant enterococci

Nine episodes of chronic peritoneal dialysis (CPD)-associated peritonitis with vancomycin resistant enterococci (VRE) were described between November 1993 and February 1996 in our dialysis unit. During the time period, 216 patients were treated for 227 episodes of peritonitis. Of the patients developing peritonitis with VRE the mean age +/- SD was 56.3 +/- 9.7 years. There were 5 females, 4 males, 5 Caucasians and 4 African-Americans. Diabetes mellitus, cardiovascular disease and gastrointestinal disease were present in 7, 8 and 7 of the 9 patients with VRE peritonitis, respectively. Patients were maintained on CPD therapy for an average of 29.9 +/- 19.2 patient months before developing VRE peritonitis. The prior rate of CPD associated peritonitis in the patients developing VRE peritonitis was significantly higher than the rate noted in the CPD patients not developing peritonitis with VRE (1 episode in 6.3 patient months vs. 1 episode in 12.5 patient months, P < 0.05). All 9 patients had used vancomycin in the six months prior to the development of VRE peritonitis and 78% had used a cephalosporin. The antimicrobial therapy used to eradicate peritonitis with VRE varied among the 9 patients with chloramphenicol used in 4 patients. The Tenckhoff catheter was removed in 6 of the 9 patients and was successfully reinserted in one patient. The catheter was not removed in 3 patients and 2 of these patients expired. Five of the 9 patients expired while being treated for VRE, 2 transferred to hemodialysis and 2 continued CPD therapy. VRE peritonitis is a major concern for patients maintained on CPD therapy. Future studies are needed with case controls to determine the significance of prior vancomycin and cephalosporin therapy, fecal VRE carriage and certain demographic data on the acquisition of VRE peritonitis. Furthermore, the optimal therapy and outcome may be better clarified through such a review.

Nitric oxide is generated on the skin surface by reduction of sweat nitrate

Nitric oxide (NO) is known to be synthesized by mammalian cells from L-arginine by a group of NO synthase enzymes. We now show that NO is generated from human skin and propose a different mechanism of production. Whereas enzymatic NO synthesis is inhibited by monomethyl L-arginine, this arginine analog, when infused into the brachial artery at concentrations sufficient to inhibit endothelial NO synthase activity, has little effect on hand skin NO production. Hand skin NO production is increased by topical acidification of the skin surface and greatly increased by the addition of nitrite solutions. We propose that NO generation from skin derives from sweat nitrite (the concentration of which was found to average 3.4 microM in six subjects) due to chemical reduction consequent to the acidic nature of sweat. Sweat contains nitrate in appreciable amounts, and skin commensal bacteria can synthesize nitrate reductase enzyme. Patients on long-term tetracycline antibiotics showed significantly reduced skin NO synthesis, although topical antiseptic and antibiotics had little effect on NO generation in the short-term. We propose that NO generation from skin is dependent on bacterial nitrate reduction to nitrite and subsequent reduction by acidification. We speculate that this has a physiologic role in the inhibition of infection by pathogenic fungi and other susceptible microorganisms and may affect cutaneous T-cell function, keratinocyte differentiation, and skin blood flow.

Antimicrobial effect of acidified nitrite on gut pathogens: importance of dietary nitrate in host defense

Dietary intake of nitrate generates salivary nitrite, which is acidified in the stomach, leading to a number of reactive intermediates of nitrogen, among which are the potentially carcinogenic N-nitrosamines. Acidified nitrite, however, also has antimicrobial activity which coincides with the formation of nitric oxide. The present study examines the antimicrobial effect in vitro of acidified nitrite on Salmonella enteritidis, Salmonella typhimurium, Yersinia enterocolitica, Shigella sonnei, and Escherichia coli O157. First-order regression plots showed a linear inverse relationship of log-transformed proton and nitrite concentrations with MICs and MBCs after 30 min, 2 h, and 24 h of exposure (P < 0.001 for all antibacterial activities). Susceptibility to the acidified nitrate solutions ranked as follows: Y. enterocolitica > S. enteritidis > S. typhimurium = Shigella sonnei > E. coli O157 (P < 0.05). Addition of SCN-, but not that of CI-, increased the antibacterial activity (paired t testing, P < 0.001). Generation of salivary nitrite from dietary nitrate may provide significant protection against gut pathogens in humans.

Chemical generation of nitric oxide in the mouth from the enterosalivary circulation of dietary nitrate

High concentrations of nitrite present in saliva (derived from dietary nitrate) may, upon acidification, generate nitrogen oxides in the stomach in sufficient amounts to provide protection from swallowed pathogens. We now show that, in the rat, reduction of nitrate to nitrite is confined to a specialized area on the posterior surface of the tongue, which is heavily colonized by bacteria, and that nitrate reduction is absent in germ-free rats. We also show that in humans increased salivary nitrite production resulting from nitrate intake enhances oral nitric oxide production. We propose that the salivary generation of nitrite is accomplished by a symbiotic relationship involving nitrate-reducing bacteria on the tongue surface, which is designed to provide host defence against microbial pathogens in the mouth and lower gut. These results provide further evidence for beneficial effects of dietary nitrate.

Depressive symptoms in patients with systemic lupus erythematosus: association with central nervous system lupus and Sjögren's syndrome

OBJECTIVE

To determine if patients with systemic lupus erythematosus (SLE) with depressive symptoms differ in regard to organ involvement and serological activity from other patients with SLE.

METHODS

Disease manifestations were compared between 71 patients with SLE with a history of depressive symptoms and 278 patients without a history of depressive symptoms by univariate analysis and multiple logistic regression.

RESULTS

Both univariate and logistic regression analysis revealed an association of depressive symptoms with neuropsychiatric lupus and secondary Sjögren's syndrome (SS). Patients with neuropsychiatric lupus had an adjusted odds ratio of 3.43 (95% CI 2.55, 4.63; p = 0.00005), and patients with secondary SS had an adjusted odds ratio of 2.97 (95% CI 2.08, 4.25; p = 0.0006) for depressive symptoms. No other organ involvement or serological abnormality was associated with depressed mood.

CONCLUSION

These discrete associations of depressive symptoms with neuropsychiatric lupus and secondary SS suggest that depression does not occur purely as a response to social stresses, and may be a manifestation of autoimmune disease in some patients.

Glycemic response to sucrose-containing mixed meals in diets of children of with insulin-dependent diabetes mellitus

Our pilot study compared the short-term glycemic effects of a traditional "sucrose free" diet (Suc-Free, 2% total calories from sucrose) to a sucrose-containing diet (Suc-Con, 10% total calories from sucrose) in a clinical research center. Both weighed diets were isocaloric and included 50% carbohydrate, 30% fat, and 20% protein in three meals and three snacks; glucose, fructose, and dietary fiber were identical. Sucrose isocalorically replaced complex carbohydrate at each meal and for the afternoon snack. Ten children (7 to 12 years of age; mean total hemoglobin A1 level 8.9 +/- 0.3%) were randomly assigned, in a crossover design, to one of the two orders (Suc-Free followed by Suc-Con or Suc-Con followed by Suc-Free) for consecutive 2-day diet periods; insulin doses remained constant. Preprandial and postprandial blood glucose levels were measured for each meal and snack (18 measurements per day). To account for baseline differences, we calculated the change in blood glucose levels from baseline to 30 minutes and 1 hour for each meal and snack (mean +/- SEM). No differences were detected between diets. Total area under the glucose response curve (levels measured hourly from 8 AM to 9:30 PM in milligrams per deciliter) was not significantly different for the two diets (Suc-Free 3672 +/- 240; Suc-Con 3574 +/- 285; p = 0.74). No difference in 24-hour urinary glucose levels (measured in grams per day) was detected between the two diets (Suc-Free 35.6 +/- 7.5; Suc-Con 34.5 +/- 7.5; p = 0.84). Incidences of hyperglycemia that required supplemental short-acting insulin and of mild hypoglycemia were similar for both diet periods. Thus, in a controlled setting and during a short study period, children with insulin-dependent diabetes mellitus had a similar glycemic response to diets with and without a moderate amount of sucrose.

Reduction in vitro of red cell glutathione reproduces defects of cellular sodium transport seen in oedematous malnutrition

Red cells in oedematous malnutrition (kwashiorkor) have an increased sodium content, 'leakiness' to sodium and enhanced sodium pumping. In non-oedematous malnutrition (marasmus) there is a reduction in the sodium pump activity. The explanation has hitherto been unknown but the glutathione content of red cells is low in kwashiorkor and normal in marasmus. We artificially lowered the glutathione content of normal red cells to values characteristic of mild oedematous malnutrition, using the enzyme inhibitors bischloronitrosourea (BCNU) and buthionine sulfoximine (BSOX). After preincubation, the cells were washed to remove the inhibitors and oxidized glutathione. Cellular content of sodium and potassium, and 86Rb influx were then measured. The reduction in glutathione reproduced the abnormalities of sodium content and flux observed in kwashiorkor. We suggest that oxidant stress in kwashiorkor, by reducing cellular glutathione, may affect cell membrane electrolyte transport. This may act through alterations in membrane sulfhydryl groups. Glutathione depletion may therefore play an important role in the clinical picture and natural history of oedematous malnutrition and may have relevance to other conditions where oxidant stress occurs.

Alteration of extracellular cation concentrations and ratios in culture medium does not affect first cleavage division of hamster zygotes in vitro nor overcome the 'two-cell block'

In vivo fertilized hamster one-cell eggs (embryos) were cultured in a simple medium that was modified to provide a wide range of concentrations and ratios of the four major cation components (sodium, potassium, calcium and magnesium) while maintaining total osmotic pressure at 290 +/- 5 mosm. Embryos were cultured in these media to find the optimum cation concentrations for supporting the first cleavage division in vitro and to determine if physiologically abnormal cation concentrations and/or ratios in standard culture media could account for the 'two-cell block' to development in vitro in this species. Despite using a broad range of ratios for sodium:potassium (from 45:1 to 5:1) and for calcium:magnesium (from 17:1 to 1:1), there were no significant differences in the proportions of fertilized eggs that underwent the first cleavage division (approx. 60-80% across all treatments), and none of the two-cell embryos underwent further cleavage during extended culture. These data demonstrate that the first cleavage division of hamster embryos in vitro is insensitive to extracellular concentrations and ratios of the major cations, and that the non-physiological concentrations and/or ratios of these cations in the culture medium are not the primary reason for the failure of hamster zygotes to develop past the two-cell stage in vitro.