Correlation between Na, K-ATPase activity and potassium and magnesium contents in skeletal muscle of renal stone patients.

Samples of external oblique muscles were surgically removed from 45 renal stone patients and analyzed for their K, Na and Mg content. The muscle samples were also measured for membrane Na, K-ATPase activity from the assay of its K+-dependent 3-0-methyl fluorescein phosphatase (K+-dependent 3-0-MFPase) activity. The results showed that the mean muscle contents +/- SEM of K, Na and Mg were 65.2 +/- 1.7 (range, 41.1 to 86.1), 45.5 +/- 2.0 (range, 23.5 to 73.2) and 6.3 +/- 1.0 (range, 4.1 to 8.5) micromol/g wet weight, respectively. The mean activity +/- SEM of the K+-dependent 3-0-MFPase or the Na, K-ATPase was calculated by subtracting the activity of the basal-form from that of the total-3-0-MFPase, which was 113 +/- 21 (range, 11 to 177) nmol/g wet weight/minute. The activity of the Na, K-ATPase showed a significant correlation with muscle K-content (r = 0.52, p<0.001) and Mg content (r = 0.45, p<0.002). Though the external oblique muscles of renal stone patients in our study, as compared to data from other sources, had a considerably low concentration of K and Mg, they exhibited a good correlation with membrane-Na, K-ATPase activity. Our results, therefore, support previous observations made by other investigators.

A long-term study on the efficacy of a herbal plant, Orthosiphon grandiflorus, and sodium potassium citrate in renal calculi treatment.

The study was performed to compare the efficacy of a herbal plant, Orthosiphon grandiflorus (OG), and the drug sodium potassium citrate (SPC) in treatment of renal calculi. Forty-eight rural stone formers identified by ultrasonography were recruited and randomly assigned to two treatment groups (G1 and G2). For a period up to 18 months, subjects in G1 received 2 cups of OG tea daily, each tea cup made from an OG tea bag (contained 2.5 g dry wt), and G2 received 5-10 g of granular SPC in solution divided into three times a day. Once every 5 to 7 weeks, subjects were interviewed, given an additional drug supply, administered a kidney ultrasound and had spot urine samples collected for relevant biochemical analysis. From the recorded ultrasound images, rates of stone size reduction per year (ROSRPY) were calculated. The mean ROSRPY was 28.6+/-16.0% and 33.8+/-23.6% for G1 and G2, respectively. These two means were not significantly different. ROSRPY values of G1 and G2 were combined and divided into three levels: Level A (ROSRPY > mean + 0.5 SD), Level M (ROSRPY = mean +/- 0.5 SD) and Level B (ROSRPY < mean - 0.5 SD). Dissolution of stones was least in Level B which was related to higher excretions of Ca and uric acid in the urine. After treatment, 90% of the initial clinical symptoms (ie back pain, headaches and joint pain) were relieved. Fatigue and loss of appetite were observed in 26.3% of G2 subjects. Our study indicates that treatment of renal calculi with OG tea is an alternative means of management. Further investigation is needed to improve dissolution of stones with a low ROSRPY.

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.

Potassium, sodium and magnesium contents in skeletal muscle of renal stone-formers: a study in an area of low potassium intake.

Skeletal muscles surgically obtained from the stone-former group (external oblique muscle; n = 202, 82 males & 120 females), control group I (external oblique muscle; n = 5, all males), control group II (rectus abdominis muscle; n = 23, all females) and control group III (quadriceps femoris muscle; n = 11, all males) were analyzed for potassium (K), sodium (Na) and magnesium (Mg) contents. Muscle samples were digested with 65 per cent HNO3 and determined for K, Na and Mg by an atomic absorption spectrophotometer. The results of analysis showed the mean K, Na and Mg (+/- S.D.) contents in mumol per one gram of fresh tissue of the stone-former group, control groups I, II and III were 73.5 +/- 16.6, 51.3 +/- 13.4 and 6.6 +/- 1.3, 77.5 +/- 3.9, 43.9 +/- 9.9 and 7.2 +/- 0.5, 83.8 +/- 27.5, 49.4 +/- 24.1 and 6.7 +/- 1.8 and 85.0 +/- 17.1, 48.5 +/- 12.1 and 6.8 +/- 1.3. Among these variables, only the K content of control group III was higher significantly (p < 0.05) than that of the stone-former group. In the stone-former group, regression analysis showed significant correlations between K and Mg contents (r = 0.856, p < 0.001) and K and Na contents (r = -0.325, p < 0.001). Due to no available data of the external oblique, we made a comparison of our results to the soleus type of skeletal muscle of normal subjects reported by Dorup et al and found that the external oblique muscle had lower mean contents of K and Mg but a higher Na content than those of the soleus. Our results were similar to the K and Mg depleted muscles obtained from the patients receiving long-term treatment with diuretic drugs. The results suggest that most of our subjects in both the stone-former and the 3 control groups were in a state of K and Mg depletion. The causes may be multifactorial, for instance low intake, high sweat loss and the existence of environmental inhibitor (s) for K transport like vanadium.

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.

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.

Some aspects of citrate metabolism in renal-stone patients from northeastern Thailand.

In our previous nephrolithiasis studies in the northeast region of Thailand, hypokaliurea and hypocitraturia were the 2 most commonly encountered metabolic abnormalities. This led us to believe that people prone to forming renal-stones in this area were in a state of potassium depletion, a condition which probably caused the low urinary excretion of citrate. Further studies on some aspects of citrate metabolism in these subjects were carried out. Two groups of adult male subjects were included in the study protocol. Group 1 consisted of 20 urban dwellers who were used as normal controls, and group 2 was comprised of 36 renal-stone patients residing in rural villages outside the municipal area. Fasting clotted venous blood and one 24-hour urine specimens were collected and analyzed for creatinine, citrate, calcium, phosphate, magnesium, sodium, potassium, chloride, bicarbonate and uric acid. Values for: creatinine and citrate clearances, the filtered load of citrate and the tubular reabsorption of citrate were then calculated. The results showed that, for both groups, the concentrations of most of the above parameters were within the normal ranges both serum and urine. An exception to this was that the levels of serum potassium and of urinary excretions of sodium, potassium and citrate in people in group 2 were significantly less than those in group 1 (p < 0.005, p < 0.001, p < 0.001 and p < 0.0001, respectively). With respect to citrate metabolism, while the serum citrate levels and the filtered load of citrate were not different between the 2 groups, the average percentage of renal tubular reabsorption of group 2 (95 +/- 1.1%) increased significantly (P < 0.0001)in comparison to group 1 (85 +/- 1.6%). Moreover when results from both groups were combined, a significant negative correlation between the renal tubular reabsorption of citrate and the urinary excretion of potassium was clearly seen (r = 0.4001, p < 0.007). Our data suggests that potassium depletion may affect the renal tubular cells in some manner which, consequently, causes an increase in renal tubular reabsorption of citrate. The final outcome of these changes in these renal stone subjects was hypocitraturia.

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.

Quetelet index, hemoglobin and parasitic infection of rural women in northeast Thailand.

The Quetelet index, hemoglobin and parasitic infection rates of adolescent and young women from 21 villages in Northeast Thailand were assessed. Data were collected in the hot, rainy and cold seasons of the year. The proportion of undernourished females varied between 10 and 15% when a cut-off point of 18.7 of the Quetelet index was chosen. 23 to 33% of the women had hemoglobin levels below 12 g%. Parasitic infection rates with various intestinal helminths were high but not related to the nutritional status or anemia.

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.

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.

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)

G-6-PD deficiency in the Pootai and the So communities in northeast Thailand.

The distribution of G-6-PD deficiency amongst two ethnic groups the Pootai and the So in northeast Thailand were studied. The prevalence of G-6-PD deficiency amongst the Pootai males was 9.7% while that amongst the So males was only 2.3%.