Convective-Controlled Double High Flux Hemodiafiltration: A Novel Blood Purification Modality

Convective-controlled double high flux hemodiafiltration (CC-DHF) was set-up using two high flux dialyzers. The convection occurred in the first while the fluid replacement took place in the second dialyzer. The system of CC-DHF basically resembled that of hemodiafiltration. CC-DHF was performed in 9 chronic hemodialysis Thai patients who had been treated with high flux hemodialysis for at least 6 months. When compared with high flux hemodialysis, CC-DHF could provide higher Kt/Vurea (2.4 ± 0.4 vs. 2.0 ± 0.4, p<0.05) and ß2-microglobulin clearance (106.2 ± 15.4 vs. 48.9 ± 6.1 ml/min, p<0.01). Following 6-month therapy of CC-HDF, the predialysis ß2-microglobulin levels were reduced by 12.7% while the values of Kt/Vurea were consistently higher than 2.7. The quality of life consistently improved during the 6 months of CC-DHF treatment. There were no differences in clinical and technical complications between CC-DHF and high flux hemodialysis. In conclusion, CC-DHF could provide performance comparable to hemodiafiltration without the need for expensive hemodiafiltration machines.

The outcomes of kidney transplantation in hepatitis B surface antigen (HBsAg)-negative recipients receiving graft from HBsAg-positive donors: a retrospective, propensity score-matched study

The outcomes of kidney transplantation (KT) from hepatitis B surface antigen-positive [HBsAg(+)] donors to HBsAg(-) recipients remain inconclusive, possibly due to substantial differences in methodological and statistical models, number of patients, follow-up duration, hepatitis B virus (HBV) prophylactic regimens and hepatitis B surface antibody (anti-HBs) levels. The present retrospective, longitudinal study (clinicaltrial.gov NCT02044588) using propensity score matching technique was conducted to compare outcomes of KT between HBsAg(-) recipients with anti-HBs titer above 100 mIU/mL undergoing KT from HBsAg(+) donors (n = 43) and HBsAg(-) donors (n = 86). During the median follow-up duration of 58.2 months (range 16.7-158.3 months), there were no significant differences in graft and patient survivals. No HBV-infective markers, including HBsAg, hepatitis B core antibody, hepatitis B extracellular antigen and HBV DNA quantitative test were detected in HBsAg(+) donor group. Renal pathology outcomes revealed comparable incidences of kidney allograft rejection while there were no incidences of HBV-associated glomerulonephritis and viral antigen staining. Recipients undergoing KT from HBsAg(+) donors with no HBV prophylaxis (n = 20) provided comparable outcomes with those treated with lamivudine alone (n = 21) or lamivudine in combination with HBV immunoglobulin (n = 2). In conclusion, KT without HBV prophylaxis from HBsAg(+) donors without hepatitis B viremia to HBsAg(-) recipients with anti-HBs titer above 100 mIU/mL provides excellent graft and patient survivals without evidence of HBV transmission.

Glutaraldehyde erythropoietin protects kidney in ischaemia/reperfusion injury without increasing red blood cell production

BACKGROUND AND PURPOSE

Recombinant human erythropoietin (rHuEPO) is currently the mainstay of renal anaemia treatment. Recently, rHuEPO has been shown to provide pleiotrophic tissue protection in various pathological conditions. However, the benefits of rHuEPO beyond anaemia treatment are limited because it increases red blood cell mass. Carbamylated erythropoietin (CEPO) is the first rHuEPO derivative that lacks erythropoietic activity but retains tissue protection properties. Since carbamylation targets lysine residues on rHuEPo, we hypothesized that targeted lysine modifications of rHuEPO may result in a novel non-erythropoietic erythropoietin.

EXPERIMENTAL APPROACH

rHuEPO was subjected to various targeted lysine modifications. In vitro cytoprotection and apoptosis were evaluated using P19 and HEK293 cells. In vivo erythropoiesis was performed by administering the derivatives to animals for 2 weeks. Renoprotection was tested on an ischaemia/reperfusion (I/R) model.

KEY RESULTS

We synthesized a novel derivative, a glutaraldehyde erythropoietin (GEPO). This construct abolished in vivo erythropoiesis. Biochemical characterization showed that GEPO was more electrostatically negative than rHuEPO. Immunoprecipitation experiments revealed that GEPO bound to the IL3RB/EPOR heterotrimeric receptor and ameliorated cellular apoptosis via the activation of Bcl-2. Notably, Bcl-2 activation was suppressed by the JAK2 inhibitor, tyrphostin AG490. In vivo experiments showed that GEPO also ameliorated kidney damage due to I/R injury both functionally and histologically.

CONCLUSIONS AND IMPLICATIONS

Herein, we describe a novel lysine-modified rHuEPO, glutaradehyde-EPO (GEPO), obtained from a simple reaction. This derivative has no erythropoietic properties but retains cell-protective characteristics both in vitro and in vivo, with promise for future use as an adjunctive treatment of kidney disease.

Angiotensin II receptor blocker partially ameliorated intrarenal hypoxia in chronic kidney disease patients: a pre-/post-study

Chronic intrarenal hypoxia has been regarded as a pathogenic factor of progressive renal damage. However, the lack of available human data has impeded the progress in this field. In this work, blood oxygen level-dependent magnetic resonance imaging was used to determine intrarenal oxygen status pre- and post-angiotensin receptor blockade (olmesartan) treatment in normal subjects, diabetic chronic kidney disease (CKD) patients and non-diabetic CKD patients. The mean R2*, which represents intrarenal oxygenation, was significantly lower in the control group than in the CKD group (12.42 ± 0.53 /s vs 18.89 ± 3.15 /s, P < 0.01), indicating the presence of intrarenal hypoxia in the CKD patients. The olmesartan treatment induced a 16.2 ± 7.7% decrement of the mean R2* in CKD patients, suggesting that this drug had an intrarenal hypoxia ameliorating effect.

Right ventricular electrocardiographic leads for detection of Brugada syndrome in sudden unexplained death syndrome survivors and their relatives

BACKGROUND

Sudden unexplained death syndrome (SUDS) is a sudden death syndrome in previously healthy Southeast Asian young adults without any structural causes of death. Many SUDS survivors show electrocardiographic (ECG) evidence of RSR' and ST elevation in leads V1 to V3, which is similar to the ECG pattern in Brugada syndrome. However, in many cases transient normalization of the ECG does not make diagnosis with standard 12-lead ECG possible.

HYPOTHESIS

To overcome this problem, we utilized the new right ventricular ECG leads to detect the Brugada syndrome in SUDS survivors.

METHODS

The subject was a Thai male patient who presented with a SUDS-like syncopal attack. He had cardiac arrest due to idiopathic ventricular fibrillation.

RESULTS

Post-resuscitation standard 12-lead ECG showed no diagnostic features of Brugada syndrome. However, ECG patterns of RSR' and ST elevations typical for Brugada syndrome could be detected at the higher intercostal space leads V1 to V3. We observed similar findings in 2 of the other 10 SUDS survivors and 4 of 23 healthy family members.

CONCLUSIONS

Our data suggest that these new right ventricular leads ECG may be helpful in detecting Brugada syndrome in SUDS survivors and their relatives.

Efficacy of enteric-coated mycophenolate sodium in patients with resistant-type lupus nephritis: a prospective study

The role of mycophenolate mofetil (MMF) is still controversial in the treatment of cyclophosphamide-resistant proliferative lupus nephritis (PLN). Enteric-coated mycophenolate sodium (EC-MPS) has less gastrointestinal adverse effects than MMF and is, therefore, increasingly utilised in organ transplantation. The aim of this study was to compare the efficacy and safety of EC-MPS versus an extended-course of intravenous cyclophosphamide (ED-IVCY) in resistant-type PLN. Thirty-one, biopsy-proven PLN, patients who failed to respond to an induction of IVCY were enrolled in a prospective, open-labelled, historically controlled study. Patients received 6 month of EC-MPS (720 mg b.i.d.) treatment. The patients in the ED-IVCY group, collected from a database, received a repeated 6-month course of monthly IVCY 0.5–1 g/m2of body surface area. Both groups received 0.5–1 mg/kg/day of prednisolone. Primary outcomes were partial or complete responses. A repeated kidney biopsy was performed to evaluate the histological response. No serious adverse events or patient deaths were observed during the study. Both groups had comparable baseline characteristics. At 6 months, the EC-MPS group had a comparable response rate with the ED-IVCY group. There were significantly less adverse events in the EC-MPS group. Repeated biopsies showed significant improvement in the EC-MPS group. EC-MPS provides salutary efficacy and safety in the treatment of resistant-type PLN and can be a suitably alternative treatment to ED-IVCY.

Comparison of middle-molecule clearance between convective control double high-flux hemodiafiltration and on-line hemodiafiltration

Hemodiafiltration (HDF) is now a well-recognized treatment modality for end-stage renal disease (ESRD) patients. It provides superior characteristics over conventional hemodialysis in many respects. On-line HDF, however, which has been mainly used in clinical practice, requires a special machine. Interestingly, the recently innovated convective-control double high-flux hemodiafiltration (CC-DHF) machine can provide HDF treatment with an adjustable convection rate by using the conventional volume-controlled dialysate flow hemodialysis machine in a modified way. The present study was conducted to compare the efficacy of CC-DHF compared to on-line HDF in terms of middle and small solute clearances in 12 stable, chronic hemodialysis patients who underwent hemodialysis three times a week for at least 6 months. The results showed that the beta 2-microglobulin (beta 2M) removal represented by the beta 2M clearance in CC-DHF was comparable to that in on-line HDF (112.4+/-17.0 vs. 119.4+/-15.5 ml/min respectively, NS). Also, the beta 2M reduction ratio in the CC-DHF group did not differ from the on-line HDF group (85.5+/-4.2% vs. 86.1+/-6.7%, NS). With regard to small solute clearances, the values of single-pool Kt/V and phosphate clearance did not differ between CC-DHF and on-line HDF groups. In conclusion, CC-DHF provides removal of beta 2M and small molecule uremic toxins that is comparable to on-line HDF. An on-line HDF machine may not be available in all hemodialysis centers, whereas CC-DHF can be easily set up, with proper precautions regarding the fluid quality. Therefore, CC-DHF can provide the benefits of convective therapy to patients in situations where use of an on-line HDF machine is limited.

Antioxidative effects of erythropoietin

Erythropoietin (EPO) has been shown to exert cytoprotective effects on erythroid progenitor cells as well as various non-erythroid cells. Experimental studies have demonstrated the renoprotective effects of EPO in various acute and chronic renal injury models. These protective effects have been largely attributed to antiapoptotic signalings of EPO. However, injured cells undergoing apoptosis are generally too severely damaged to function properly. Therefore, simply corrupting apoptotic pathway is unlikely to be an effective strategy, because the remaining damaged cells may not function appropriately, or they may eventually undergo necrotic cell death. Recent evidences suggest that EPO also provides cytoprotection by ameliorating oxidative stress, the principal cellular insult. EPO may exert its antioxidative effects directly by exploiting intracellular antioxidative mechanisms such as heme oxygenase-1 and glutathione peroxidase. In addition, EPO may act indirectly by inducing iron depletion and thereby inhibiting iron-dependent oxidative injury. Increasing red blood cells by EPO may also indirectly reduce cellular oxidative stress, as red blood cells are loaded with a substantial amount of antioxidative enzymes. Further investigation regarding the mechanisms of cellular antioxidative responses to EPO would provide a better insight to cytoprotective action of EPO, and would support the development of better cytoprotective drugs in the near future.

Measurement of urinary chemokine and growth factor messenger RNAs: A noninvasive monitoring in lupus nephritis

Noninvasive molecular tests of urine cells have been developed to monitor the activity of kidney diseases. We evaluate whether measurement of urinary messenger RNA (mRNA) levels of chemokine and growth factor genes could distinguish between diffuse proliferative lupus nephritis (class IV LN) and others and whether it is able to predict the response to therapy. Prebiopsy urine samples were collected from 26 LN patients. Urine specimens were serially collected over a period of 6 months from class IV LN patients who were receiving standard immunosuppressive treatments. Urinary interferon-producing protein 10 and its CXC chemokine receptor (CXCR)3, transforming growth factor-beta (TGF-beta), and vascular endothelial growth factor (VEGF) mRNA levels were analyzed by quantitative real-time polymerase chain reactions. Levels of chemokine or growth factor mRNAs in urine could distinguish class IV LN from others, with a sensitivity of 85% and a specificity of 94%. The receiver-operative characteristic curve demonstrated that urine mRNA levels of these genes could identify active class IV LN with an accuracy greater than the current available clinical markers, namely systemic lupus erythematosus (SLE) disease activity index, proteinuria, renal function, or urinalysis. A significant reduction of interferon-producing protein 10 (IP-10), CXCR3, TGF-beta, and VEGF mRNA levels from baselines was observed in patients who responded to therapy, whereas the levels tended to increase in those who resisted to treatment. Measurement of urinary chemokine and growth factor mRNAs can precisely distinguish class IV LN from others. Temporal association between these markers and therapeutic response is demonstrated. This noninvasive approach serves as a practical tool in diagnosis and management of LN.

Monitoring of T-cell subsets in patients treated with anti-CD 25 antibody

Daclizumab and basiliximab, the antibodies to the interleukin-2 receptor (anti-IL-2R), decrease the incidence of acute rejection in renal transplantation. However, prolonged blockade of IL-2 receptor (IL-2R:CD25) may hamper apoptosis of reactive T-cell clones and thus may obstruct tolerance induction. We determined the effect of varying doses of anti-IL-2R on the number of CD3+CD25+ cells as an index of CD 25 blockade. The number of CD3+CD25+ cells was determined in four groups of induction therapies: no antibody induction; two doses of 50 or 25 mg daclizumab on day 0 and day 14; and two doses of 20 mg basiliximab at day 0 and day 4 (n=10, 24, 10, and 10, respectively). The number of CD3+CD25+ cells were monitored in whole blood before antibody infusion as well as 24 hours thereafter and weekly after transplantation. With two doses of 50 mg daclizumab, two doses of 25 mg daclizumab, and two doses of 20 mg basiliximab, the expression of CD3+CD25+ cells was completely suppressed for 12, 10, and 12 weeks posttransplantation, respectively. The reappearance of CD3+CD25+ cells above the baseline for each induction regimen was: 17 weeks for two doses of 50 mg daclizumab, 11 weeks for two doses of 25 mg daclizumab, and 13 weeks for two doses of 20 mg basiliximab. Monitoring of CD3+CD25+ cells may be utilized to tailor anti-IL-2R administration at a minimal dosage, yet retaining adequate IL-2R blockade for at least 3 months posttransplantation.

New electrocardiographic leads and the procainamide test for the detection of the Brugada sign in sudden unexplained death syndrome survivors and their relatives

AIMS

Sudden unexplained death syndrome occurs in previously healthy South-east Asian young adults without any structural cause of death. The common electrocardiographic (ECG) change in sudden unexplained death syndrome survivors is right bundle branch block and ST elevations in leads V(1) to V(3), which are similar to the ECG pattern in the Brugada syndrome (Brugada sign). It is difficult to diagnose the Brugada sign with the 12-lead ECG in sudden unexplained death syndrome survivors and their family members because the ECG could be transiently normalized. We proposed using the higher intercostal space V(1) to V(3) lead ECG, together with procainamide to detect the Brugada sign.

METHODS AND RESULTS

Among 20 ventricular fibrillation cardiac arrest patients, 13 sudden unexplained death syndrome survivors and their relatives (n=88) were studied using the single standard 12-lead ECG and the new six higher intercostal space V(1) to V(3) lead ECG (-V(1) to -V(3) and -2V(1) to -2V(3)). Ten sudden unexplained death syndrome survivors and relatives (n=48) who had a normalized ECG were also infused with procainamide (10 mg x kg(-1)i.v.) to unmask the Brugada sign and both ECG methods were recorded. Forty healthy individuals and 13 spouses served as the control group. Prior to the procainamide infusion, the Brugada sign could be detected in nine sudden unexplained death syndrome survivors (69.2%) and three (3.4%) relatives with the standard ECG and in 12 (92.3%) and nine (10.2%) with the new six-lead ECG. After the procainamide infusion, the Brugada sign could be demonstrated in seven sudden unexplained death syndrome survivors (70%) and seven (14.6%) relatives with the standard ECG and in nine (90%) (P=0.26) and 23 (47.9%) (P=0.0004) with the new six-lead ECG, respectively. All the controls were negative for the Brugada sign.

CONCLUSIONS

Our data suggest that the new higher intercostal space lead ECG, with or without the procainamide test is helpful in detecting the Brugada sign in sudden unexplained death syndrome survivors and their relatives.

Potassium status of Northeast Thai constructors in three different geographic locations

Sudden and unexpected death of young adults during sleep is a phenomenon among Southeast Asians and particularly young Northeast (NE) Thailand constructors in Singapore. Survivor of sudden unexplained death syndrome (SUDS) without structural heart disease with idopathic ventricular fibrillation (VF) has been documented. Low plasma potassium (K) and depletion of K can occur simply through a reduction of K intake and are associated with increased risk of VF. The K-status of the populations was evaluated in the NE (Group 1, n=30), Bangkok (Group 2, n=48) and Singapore (Group 3, n=46). Groups 2 and 3 were further subdivided into Group 2A (worked in Bangkok < or = 1 year, n=8), Group 2B (worked in Bangkok > 1 year, n=40), Group 3A (consumed self-prepared or ready-to-buy meals, n=25) and Group 3B (regularly consumed foods provided free-of-charge by construction companies, n=21). Thirty-four male healthy university personnels from the NE and Bangkok served as the control--Group 4. Two 24-h urine samples and a fasting blood sample were collected from each subject. Dietary-K from food was determined by duplicated meal analysis. All these samples were then analyzed for their K-content. Group 3A had the lowest K-status: their K-intake, serum-K, and urinary-K level were 29 +/- 5.8 mmol/day (% low K-intake=100), 3.43 +/- 0.34 mmol/L (% hypokalemia=48) and 19.23 +/- 8.2 mmol/day (% hypokaliuria=87.5), respectively. Among the construction workers, average K-intake, serum-K and urinary-K levels were 45.5 +/- 6.1 mmol/day (% low K-intake = 37.5), 3.93 +/- 0.2 mmol/L (% hypokalemia = 2.5) and 39.6 +/- 9.2 mmol/day (% hypokaliuria = 12.5), respectively. The values of Group 2B were similar to Group 4. In addition, when the data from all of the groups were compared, there was a positive correlation between dietary-K (intake) and urinary-K (excretion) (r=0.881, p<0.001). In conclusion, NE Thailand constructors from various locations exhibited low K status with low dietary-K, high incidence of hypokalemia, and low urinary-K. From the present study, this low K status may be an important trigger factor for VF in construction workers and associated with increase risk of SUDS.

Pharmacokinetic studies of cyclosporin in Thai kidney transplantation patients

Pharmacokinetic studies were performed in 10 Thai patients with kidney transplantation who received microemulsion formulation (Neoral) of cyclosporin A (CsA) twice daily. No agents having pharmacokinetic effect on CsA had been used in these patients. The mean values of 12-h AUC (area under the concentration-blood curve) were 4603.63 +/- 344.61 ng x h/ml. CsA concentrations at 2 hours after dosing had the best value of correlation coefficient with the 12-h AUC. Abbreviated AUC could be calculated by stepwise multiple linear regression analysis and linear trapezoidal rule. The latter is more simple and superior to the former one.

Potassium needed for maintaining its balance in healthy male subjects residing in an area of low potassium intake and with a high environmental temperature

Low potassium (K) intake and high prevalence of hypokalemia and hypokaliuria among rural dewellers in the northeast region of Thailand have been repeatedly reported and they were speculated to be in a state of low K status. In this communication we studied K balance of 10 rural (R) and 5 urban (U) male subjects in this region during a 10-day period of semi-free-living and eating group-selected diets. While K in intake, 24-h urine and feces were measured daily in all subjects, the direct measurement of K lost in sweat was made only in one subject coded R3. These parameters were then used to calculate the K balance. The results showed that mean K intakes were 1731 +/- 138 and 1839 +/- 145 mg/day for R and U subjects, respectively. Their mean K balances, calculated by subtracting the K excretions in 24-h urine (721 +/- 129 mg/day for R and 919 +/- 186 mg/day for U) and in feces (148 +/- 25 mg/day for R and 164 +/- 21 mg/day for U) from intakes, were +860 +/- 140 and +756 +/- 222 mg/day for R and U, respectively. In the subject R3, his mean K balances without and with subtracting the sweat K excretion (451 +/- 57 mg/day), were +847 +/- 373 and +396 +/- 344 mg/day, respectively. Regression of K balance versus intake indicated that R and U subjects needed K of 832 and 884 mg/day to stay in balance. Since the study was performed during the hot season (average temperature = 35.2 +/- 2.0 degrees C at 3 pm) and sweating was clearly observed (estimated sweat volume per day was 1927 +/- 420 ml for R and 1759 +/- 408 ml for U), therefore, K balance calculated without sweat K was overestimated. This was apparently seen in the subject R3 where he actually needed K of 1203 mg/day, instead of 814 mg/day calculated without sweat K, to stay in balance. The similarities in K balance data among the two groups suggested they both had the same food habit and K status. Our results indicate that any calculation for the levels of dietary K, or probably also for other minerals, to achieve the balance could be underestimated if loss via sweat is not taken into consideration.

Environmental distal renal tubular acidosis in Thailand: an enigma

Distal renal tubular acidosis is a common health problem in northeastern Thailand, with the population background of the low potassium intake, low urine citrate, and decreased red blood cell Na-K adenosine triphosphatase (ATPase) activity and the environment of the high soil vanadium. The disease is usually seen in the people with low socioeconomic status in summer. The patients have decreased gastric acidity and low urine potassium. There are varying degrees of renal function from normal to impairment. Gastric hypoacidity is an important clue. Defects in H-K ATPase and anion exchange (AE2) mechanism are considered. The urine vanadium is higher in the patients than that of normal rural northeastern villagers. Inhibition of H-K ATPase by vanadium seems possible and requires more supporting evidence. AE1 gene mutation is noted in few patients. The cause of dRTA is not apparent. The AE2 gene and H-K ATPase gene remain to be studied. Both environmental and genetic factors could contribute to the pathogenesis of the disease.

Potassium contents of northeastern Thai foods

From our previous nutritional assessment, low potassium (K) intake among northeastern Thai males has been clearly demonstrated. This prompted us to undertake a survey of the K content of local foods. Food samples comprised of 57 animal and 142 plant products which were collected from various places in the northeast of Thailand. The dry ashing method was used to prepare the samples for K analysis using an atomic absorption spectrophotometer. Foods could be divided into 7 groups according to their K levels. Foods containing K > or = 1000 mg per 100 g fresh food were categorized in group 1. These were mainly foods in the legume group, i.e., soybean, cowpea and mungbean. While rice (polished) and rice products, the main staple, were in group 7, the lowest K group of less than 100 mg per 100 g fresh food. Comparison studies of the natural foods between those collected from the northeast and from the central regions of the country, and between the cooked foods purchased from the rural villages and from the urban areas of Khon Kaen municipality, showed that, for most food items, the K content was similar wherever it came from. However, when the K content in various parts or in different stages of growth of the same kind of plants or animals was compared, a great variation was clearly seen, for example, young tamarind leaves contained K in group 6 whereas ripe tamarind fruit contained K in group 1. According to our food consumption data, the analysis of food components of 48 meals taken during the hot season by 13 rural volunteers revealed that food items eaten with the highest frequencies and in the largest amount were those in the low K food groups, i.e., glutinous rice (group 7) and green papaya (group 6). Our results suggest that the low K intake of these northeast rural Thai people is not due to a low K content of foods in this region, but rather that their food habits and low socioeconomic status restricts consumption of those food items with higher K contents.

Nutritional potassium status of healthy adult males residing in the rural northeast Thailand

Sixteen villages from rural areas of 8 provinces in the northeastern region of Thailand were randomly selected as study sites. Data on potassium (K) contents in 24-hour urine and serum samples of 93 healthy adult volunteer males aged 20-50 years old were completely collected and covered all 3 seasons of the year. The method of direct weighing of food was used to assess K intake in 13 subjects. K loss through sweat during working (9 hours) in the field was measured in 14 subjects by soaking their worn-clothes in distilled water after which K contents were measured by the flame photometry method. The results showed that the means urinary K excretion of 93 subjects were less than that of the cut-off value for normal (> or = 30 mmol/day) in all seasons of which 76.71%, 90.71% and 81.02% of the urine were categorized as hypokaliuria in the hot, rainy and cold seasons, respectively. In the case of serum K of these subjects, though the mean values were within a normal limit (> or = 3.5 mmol/l), 36.56%, 34.41% and 29.03% of the serum were classified as hypokalemia in the hot, rainy and cold seasons, respectively. In the assessment of K intake, it was clearly demonstrated that the values in all 3 seasons were much lower than that of the estimated safe and adequate daily dietary intake (ESADI) of K for the westerners (1975-5625 mg/day), i.e., the means of intake in the hot, rainy and cold seasons were only 807 +/- 172, 877 +/- 257 and 902 +/- 227 mg/day, respectively. Furthermore, K loss through sweat in the cold and the hot seasons were as high as a third (7.4 +/- 2.4 mmol/day) and a half (11.5 +/- 1.6 mmol/day), respectively, of the urinary excretion. Though the total body K contents were not evaluated in this study, our results suggest rural people in the northeast region of Thailand may be in a state of K deficiency. The severity is probably worsened in the hot season as seen from the tendency of decrease in serum K levels among 650 renal stone formers and 260 blood donors in this season.

Low erythrocyte Na/K-pump activity and number in northeast Thailand adults: evidence suggesting an acquired disorder

Healthy northeastern Thais have a higher erythrocyte sodium concentration and a lower erythrocyte membrane Na,K-adenosine triphosphatase (ATPase) activity than central Thais. To elucidate whether the defect is hereditary or acquired, we studied plasma sodium and potassium and erythrocyte sodium, potassium, Na,K-ATPase activity, and ouabain-binding sites (OBS) in the following groups: healthy newborns of ethnic central Thais (group 1), healthy newborns of ethnic northeast Thais (group 2), healthy adults of central Thailand ethnicity who lived in the rural central region (group 3) or in Bangkok (group 4), healthy adults of northeast Thailand ethnicity who lived in the rural northeast region (group 5) or who migrated to work in Bangkok for at least 1 year (group 6). Erythrocyte Na was higher in group 2 than in group 1. Group 3 had lower erythrocyte Na,K-ATPase activity than group 4, and it was lower in group 5 than in group 6. Among all groups, group 5 had the highest erythrocyte Na (11.6 mmol/L,F < 0.0001) and the lowest Na,K-ATPase activity (63 mmol Pi/mg x h, F < 0.0001) and erythrocyte OBS (397 sites per cell, F < 0.05) than the other adult groups. There was a positive correlation between erythrocyte Na,K-ATPase and erythrocyte OBS (r = .416, P < .0001). Multiple regression analysis demonstrated a correlation between erythrocyte Na as a dependent variable and erythrocyte OBS, plasma potassium, erythrocyte potassium, and erythrocyte Na,K-ATPase (r = .517, P < .0001). The erythrocyte Na,K-ATPase/OBS ratio, an expression of Na,K-ATPase activity equalized for the number of Na,K-pump units, was lowest among rural adults of the central region (group 3) and the northeast region (group 5) (F < 0.0002). Our data suggest that rural dwellers in Thailand tend to have lower erythrocyte Na,K-ATPase activity than urban dwellers and that this is probably acquired after birth. It was more severe among those from the northeast versus the central region, and was less severe among those who migrated to an urban area. This defect in northeast rural dwellers was probably associated with low numbers of Na,K-pump units and a defect of the pump to express activity, whereas in central rural dwellers it was probably associated with the latter condition. We postulate that there might be circulating Na,K-pump inhibitors and metabolic disturbances that cause attenuation of Na,K-ATPase function and synthesis in the northeast Thailand rural population, and that such substances may have an environmental origin. There may be a relationship between these abnormalities and sudden unexpected deaths.

Increased risk of urinary stone disease by physical exercise

Constituents of 6-hour (0900-1500 hours) urine collected during rest and exercise have been compared among 3 groups of male volunteers. Groups 1 and 2 (GI, GII) were normal controls residing in an urban area (n = 10) and rural villages (n = 9), respectively, and group 3 (GIII) consisted of 10 renal stone formers from the same location as GII. Exercise was performed by cycling on an electronic bicycle with three 150-watt loads and the duration of each load was 20 minutes. Collected usine was analyzed for volume, pH, PI (permissible increment) in oxalate, creatinine, calcium, sodium, potassium, phosphorus, oxalate, uric acid and citrate. The results showed that most urinary excretions during both rest and exercise periods were similar among the 3 groups. Only the following values were significantly different, ie in the rest period, calcium of GIII < GII (p < .01) and potassium of GII < GI (p < .05); in the exercise period, potassium of GIII < GI (p < .02) and phosphorus of GIII < GII (p < .03). In comparison between the rest and exercise periods within each group, the decreased total excretions during exercise were creatinine of GI (p < .05) and GIII (p < .05), calcium of GII (p < .05) and phosphorus of GIII (p < .05); only calcium of GIII (p < .05) was increased. However, when the concentration of each constituent was taken into consideration, most constituents increased in concentration during the exercise period due to the fall in urinary volume. Furthermore, during exercise both pH and PI in oxalate of urine decreased significantly. Thus the results of our study suggested that though most total urinary excretion patterns were similar between the rest and exercise periods, the risk of stone formation in the urinary tract during exercise could be enhanced. The enhanced risk is likely due to 3 main factors, ie (1) decrease in urinary volume, (2) increased propensity for crystallization of calcium oxalate (PI in oxalate decreased) and (3) decrease in urinary pH which will directly cause an increase in saturation level of uric acid. This increased risk of stone formation was consistently observed in all three groups of subjects.

Hypokalemia, high erythrocyte Na+ and low erythrocyte Na,K-ATPase in relatives of patients dying from sudden unexplained death syndrome in north-east Thailand and in survivors from near-fatal attacks

The sudden unexplained death syndrome (SUDS) is a sudden death of unknown cause in healthy South-East Asians. In Thailand, it is common in the North-East region. We previously reported high incidences of low erythrocyte sodium and potassium-activated adenosine triphosphatase (Na,K-ATPase) activity and of high erythrocyte sodium in North-East Thais and speculated that this metabolic defect might be associated with the high incidence of SUDS in that region. In this communication, we studied plasma sodium and potassium, erythrocyte sodium and potassium, activities of erythrocyte Na,K-ATPase, ouabain-insensitive ATPase and total ATPase in healthy Thai blood donors from Central Thailand (group 1), healthy North-East city dwellers (group 2), relatives of SUDS victims (group 3) and survivors from SUDS-like attacks (group 4). Compared with groups 1 and 2, group 3 and 4 subjects had significantly lower plasma potassium (p < 0.0001), higher erythrocyte sodium (p < 0.0001), lower activities of erythrocyte Na,K-ATPase (p < 0.0001) and of erythrocyte total ATPase (p < 0.0001). In addition, group 4 subjects had lower plasma potassium, higher erythrocyte sodium and lower activity of total ATPase than those of group 3. The findings suggest that the pathogenesis of SUDS could be related to hypokalemia and a membrane sodium/potassium pump defect.

Hypouricemia, hypokalemia, proximal and distal tubular acidification defect following administration of outdated tetracycline: a case report

A Thai female patient developed muscular weakness, hypouricemia, hypokalemia and hyperchloremic metabolic acidosis after taking outdated tetracycline. A pathophysiologic study shows a proximal tubular defect for reabsorption of urate and bicarbonate and a distal tubular acidification defect, probably caused by outdated tetracycline.

Reversible severe neutropenia after ceftriaxone

A 57-year-old woman developed severe neutropenia during treatment of an upper urinary tract infection with intravenous ceftriaxone. The dosage was 1 g/day for 18 days. There was a return to normal granulopoiesis after the drug was discontinued.

Seasonal changes in serum and erythrocyte potassium among renal stone formers from northeastern Thailand

Hypocitraturia, hypokalemia and low urinary excretion of potassium are common findings in nephrolithiasis in Northeastern Thailand. However, intracellular potassium has not been studied. We measured serum potassium, erythrocyte potassium, 24-hour urinary excretion of sodium, potassium, citrate, ammonium, titratable acid and pH in 17 nephrolithiasis patients from Northeastern Thailand during 2 seasons: the cool and hot months. There were no significant differences in urinary pH, ammonium, titratable acid, citrate and potassium during these 2 seasons. However, hypocitraturia and hypokaliuria were observed in the majority of cases in both periods. Seasonal variation in serum potassium, erythrocyte potassium, urine volume and urinary excretion of sodium was observed. Values were significantly lower in the hot months. In the cool months, the urinary excretion of citrate correlated linearly with that of potassium (r = 0.696, p < 0.002). Such a correlation was not found in the hot months. We concluded that extracellular and intracellular potassium depletion might be present in these patients and is greater during the hot than during the cool months. The pathogenesis may be multi-factorial.

Sudden unexplained death syndrome in north-east Thailand

To study sudden unexplained death syndrome (SUDS) in north-east Thailand, a mailed screening questionnaire and direct retrospective interview of relatives or witnesses of the incident was carried out in four administrative districts of Khon Kaen Province, north-east Thailand. Healthy villagers, 20-49 years, who died suddenly without explanation were identified as cases. Live healthy villagers who were age- and sex-matched with the dead served as controls. The study showed that all but one case were male with a mean age of 38 +/- 8 years. The incidence of SUDS was 38 per 100,000 men 20-49 years old per year. The peak risk was at 45-49 years. About 75% of SUDS cases had an annual income per household of less than the mean per capita income in Thailand. There were more SUDS cases in the hot season than any other season. The onset was nocturnal in 84% of cases. Presence of SUDS in family members was more frequently found in cases than in controls (P < 0.001). A history of muscle soreness, malaise and recent hard labour were seen as frequently in SUDS victims as in controls. In witnessed cases, symptoms usually lasted for a few minutes prior to death. Common symptoms or signs were respiratory (groaning, choking or coughing) and muscular spasticity or paralysis. The most consistent but yet unexplained finding in this study is the association between the onset of SUDS and the rest period.

Abnormal erythrocyte Na, K-ATPase activity in a northeastern Thai population

We studied the cellular membrane enzyme responsible for potassium transport in different Thai populations. We measured plasma and intraerythrocytic concentrations of sodium and potassium, activities of erythrocytic membrane Na, K-activated adenosine triphosphatase (Na, K-ATPase), ouabain-insensitive ATPase, total ATPase and the activity ratio of Na, K-ATPase/total ATPase in 25 healthy blood donors at Khon Kaen University Hospital, Khon Kaen (group 1), and in 32 donors at the National Blood Center, Thai Red Cross Society, Bangkok (group 2). Group 1 subjects had significantly higher concentrations of erythrocyte sodium (p < 0.001) and lower activity of Na, K-ATPase (p < 0.001) than group 2. When data of these 2 groups were combined, erythrocyte Na+ correlated inversely with Na, K-ATPase and the activity ratio of Na, K-ATPase/total ATPase. Our study suggests that there is a defect in membrane transport enzymes for sodium/potassium in certain northeast Thai populations.

Prevalence of upper urinary tract stone disease in a rural community of north-eastern Thailand

A survey was conducted of upper urinary tract stone (UUTS) disease in an administrative subdivision of Khon Kaen Province in Thailand. Initial case screening was done by direct contact with the village health volunteers and village health communicators. A positive patient was defined as one who had had surgery for UUTS, previously been diagnosed by physicians, or had a history of stone passage. Those who belonged to the latter 2 categories were confirmed radiologically. The prevalence of UUTS was 3.76/1000. The male/female ratio was 2:1. The average age was 50 +/- 13 years (range 8-71). Common associated symptoms were back pain, abdominal pain, painful urination, stone passage and blood-stained urine; 75% of the patients were from a poor socio-economic class. The data suggest that UUTS is common in north-eastern Thailand. Although this is an approximate and, perhaps, an underestimated prevalence, the present method is cost-effective, efficient and appropriate for conducting community surveys in developing nations.

Urinary acidification in renal stone patients from northeastern Thailand

Hypokalemia, hypokaliuria and hypocitraturia are common findings in patients with renal stone disease in Northeastern Thailand. However, hyperchloremic metabolic acidosis seldom is seen. Therefore, we studied renal acidification in 29 renal stone disease patients who were living in rural Northeast Thailand. Baseline blood and average 24-hour urine biochemical parameters were measured. Hypokalemia, hypokaliuria and hypocitraturia were found in 10%, 83% and 93% of the patients, respectively. By multiple regression, urinary citrate excretion correlated positively with serum potassium and urinary potassium excretion, and negatively with urinary ammonium (r = 0.640, p = 0.005). An abnormal response to acid loading was found in only 1 patient. Thus, hypokaliuria and hypocitraturia in our renal stone disease subjects were infrequently due to distal renal tubular acidosis. Perhaps potassium depletion might be a contributing factor in these metabolic abnormalities.

Plasma amino acid patterns in normal Thais and in patients with chronic renal failure

The effect of chronic renal failure (CRF) on the pattern of plasma free amino acid concentrations was studied in 22 healthy controls (group 1); 43 CRF patients of which serum creatinine levels were 2-4.9 mg/dl (group 2, n = 11), 5-10 mg/dl (group 3, n = 10), more than 10 mg/dl (group 4, n = 9), and chronically hemodialysed patients (group 5, n = 13). In all renal failure groups, plasma concentrations of eight free essential amino acids-isoleucine, leucine, lysine, methionine, threonine, tryptophan, tyrosine and valine and those of three non-essential amino acids-alanine, glutamate and serine were significantly lower than those in controls. Plasma concentrations of free arginine, cystine, glutamate and serine were significantly higher in CRF patients. Patterns of change of plasma aminogram were similar among CRF patients regardless of the stages of renal function or dialytic treatment. Stepwise changes of some plasma free amino acids were observed as renal function became worse. The molar ratios of plasma free valine/glycine, serine/glycine and tyrosine/phenylalanine were decreased accordingly. Our study confirms the presence of abnormal plasma aminogram, specifically that of essential amino acids, in CRF. Therapeutic intervention is warranted but still needs further investigations.

Blood and urinary aggregator and inhibitor composition in controls and renal-stone patients from northeastern Thailand

Renal-stone disease (RSD) is common in the rural communities of northeastern Thailand. We report the biochemical composition of blood and urine in 25 healthy city dwellers (G1), 12 healthy village dwellers (G2) and 25 village dwellers who had RSD (G3). They were male with a range of ages between 20 and 50 years and were free of renal failure, urinary infection, urinary obstruction and systemic illness. The results showed that hypocitraturia, hypokalemia and hypokaliuria were more common in the latter 2 groups. The 24-h urinary citrate excretion correlated significantly with urinary potassium in G3 cases (r = 0.704, p = 0.0002). After potassium chloride supplementation, serum and urinary potassium increased remarkably (p less than 0.003 and p = 0.002, respectively), whereas urinary citrate remained unchanged. Our results suggest that the predominant abnormality in our RSD patients were hypocitraturia and potassium deficiency and that these may be related.

Measurements of urinary state of saturation with respect to calcium oxalate and brushite (CaHPO4.2H2O) in renal stone formers

Urinary supersaturation with respect to calcium oxalate and/or brushite (CaHPO4.2H2O) is critical for the formation of calcium stones. The aim of this study is to use concentration product ratio (CPR) as a tool to assess the state of urine saturation with respect to calcium oxalate and brushite. One 24-h urine specimen from each of 16 healthy city dwellers (GI), 18 healthy villagers (GII) and 28 villagers with renal stones (GIII) was collected and analyzed for calcium, sodium, potassium, phosphate, uric acid, citrate and oxalate. The CPRs of calcium and oxalate and of calcium and phosphate before and after equilibration of the urine with the corresponding seeding crystals were also determined. Urinary volume and the excretion rate of calcium, potassium, uric acid, citrate and oxalate of GII and of sodium, phosphate, uric acid and citrate of GIII were significantly less than those of GI. The CPRs for calcium oxalate and brushite were 2.9 +/- 0.3 and 1.7 +/- 0.2 for GI, 2.7 +/- 0.2 and 1.3 +/- 0.1 for GII and 2.5 +/- 0.2 and 1.1 +/- 0.1 for GIII, respectively. The CPR values indicated that urine of all groups was generally supersaturated with respect to calcium oxalate salt (CPRs were above 1) and were not different among the groups. With regard to brushite, urine was also supersaturated but the state of supersaturation was less than that of calcium oxalate. Furthermore, instead of being supersaturated, brushite in many urine specimens of GIII was undersaturated and its mean CPR was even significantly less than that of GI (P less than 0.01).

Low specific gravity urine with crystalluria as discriminant index for nephrolithiasis

A community-based study for crystalluria in morning urine (MU) specimens was carried out under light microscopy. The MU specimens were collected from 29 males with renal stones (GI), 36 age-and sex-matched normal controls (GII) and 27 household members of GI who did not have stones (GIII). The findings can be summarized as follows. 1. In the groups as a whole, almost all crystal and crystal aggregate found was oxalate type and with highest prevalence in GI. 2. In urine with low specific gravity (SG) i.e. less than or equal to 0.010, prevalence of oxalate crystals in GI (57.7%) was significantly higher (p less than 0.05) than in both GII (5.9%) and GIII (13%). Furthermore, at this range of SG, 15 per cent of the MU specimens in GI showed aggregation of oxalate crystals, whereas, the condition was neither found in GII nor GIII. 3. Our data suggest urine supersaturation with respect to calcium oxalate was found in both renal stone patients and normal subjects but more frequently in the former and also suggests more deficiency or lack of inhibitors for oxalate crystal nucleation and aggregation in urine of renal stone patients. The occurrence of oxalate crystals and crystal aggregates in urine of low SG may be useful as an index to discriminate stone patients from normal subjects or as an index to indicate the high risk group in the community.

Effect of a change in the place of urine collection on urine composition

Completeness of urine collection and food intake can influence urinary biochemical composition (UC). These variables depend in part upon whether patients are ambulatory or in-patients. This study was conducted to see whether the change in the place of urine collection from village to hospital would affect UC. Six consecutive 24-hour urinary measurements for creatinine (cr), urea nitrogen (urea-N), calcium (Ca) and sodium (Na) were made in 8 normal male volunteers. The first three 24-hour urine specimens (UV) were collected at home and the last three when they were in the hospital. Food consumed while subjects were in their village was recorded and prepared in the same manner for the same subjects when they were at the hospital. Comparing the values between at the village and at the hospital, the urinary cr, urea-N, Ca and Na increased disproportionately with the average hospital/village ratio of 1.17, 1.20, 1.50 and 1.09 respectively. The median of relative rate of increase of urinary urea-N, Na and Ca compared to that of cr, being expressed as (hospital/village UV urea-N)/(hospital/village UV cr), (hospital/village UV Na)/(hospital/village UV cr) and (hospital/village UV Ca)/(hospital/village UV cr) respectively, were 1.00, 0.97 and 1.30 respectively. The data indicated that the change in urinary urea-N and Na when the subjects were at the hospital was mainly due to completeness of urine collection. In contrast, marked increment in UV Ca at the hospital was accounted for factor(s) by other than completeness of urine collection per se. The difference in dietary Ca intake between village and hospital might have been responsible in part for the changes.(ABSTRACT TRUNCATED AT 250 WORDS)