Biomedical subjects

Beverley Adams-Huet

Publications and source records attributed to Beverley Adams-Huet.

At least 19 recordsLinked to original sources

PubMed2006

Growth hormone treatment improves growth and clinical status in prepubertal children with cystic fibrosis: results of a multicenter randomized controlled trial.

CONTEXT: This multicenter, randomized, controlled, crossover trial of prepubertal children with cystic fibrosis (CF) tests the hypotheses that recombinant human GH (rhGH) treatment 1) improves height, weight, lean mass, and bone content irrespective of baseline measures; 2) improves clinical status and quality of life; and 3) has continued effect after cessation after 1 yr of treatment. METHODS: Sixty-one prepubertal subjects (<or=25th percentile for height and weight) were randomized into two groups: daily rhGH treatment or no treatment groups for 1 yr. In yr 2, treatments were crossed over. Outcome measures included serial standardized height and weight, number of hospitalizations and antibiotic courses, random blood glucose levels, lean mass, bone mineral content, pulmonary function, nutritional intake, and CF quality of life questionnaires. RESULTS: Groups were similar at baseline and prepubertal during the entire study. After 1 yr, GH showed significantly greater gain in height, weight, lean mass, and bone mineral content. Gain in height was similar regardless of baseline. There were fewer hospitalizations in the rhGH-treated group and improvement in CF quality of life questionnaires measures of weight and body image. There was no difference in pulmonary function between groups. Results were similar in those treated with rhGH the second year. After cessation of rhGH treatment, there was sustained effect for increased height and weight velocity, as well as accrual of bone mineral. CONCLUSION: rhGH therapy improves height and weight, decreases the number of hospitalizations, and improves quality of life in prepubertal children with CF. These effects are sustained after rhGH is discontinued.

Body Height↗

PubMed2006

Influence of body fat content and distribution on variation in metabolic risk.

OBJECTIVES: Several reports indicate that the body fat compartments, especially ip fat, predict metabolic risk better than total body fat. The objective of the study was to determine whether this can be confirmed and generalized throughout the population. PARTICIPANTS: A representative sample of 1934 Black and White women and men of the Dallas Heart Study participated in the study. DESIGN: We measured the fat in total body, trunk, and lower body with dual-energy x-ray absorptiometry and in abdominal compartments (sc, ip, and retroperitoneal) with magnetic resonance imaging. Other measurements included body mass index (BMI), waist circumference, blood pressure, plasma lipids, glucose, insulin (including homeostasis model), and C-reactive protein. RESULTS: In all groups, total body fat correlated positively with key metabolic risk factors, i.e. homeostasis model, triglyceride/high-density lipoprotein-cholesterol ratios, C-reactive protein, and blood pressure; however, it explained less than one third of the variability of all the risk factors. After adjustment for total body fat, truncal fat conferred additional positive correlation with risk factors. Furthermore, with multivariable regression analysis, ip fat conferred independent correlation with plasma lipids beyond a combination of other compartments including truncal fat. Still, except for insulin levels, all combinations including ip fat still explained less than one third of the variability in risk-factor levels. Conversely, lower body fat correlated negatively with risk factors; i.e. lower body fat appeared to offer some protection against risk factors. CONCLUSIONS: Body fat distribution has some influence on risk factors beyond total body fat content. Both waist circumference and BMI significantly predicted risk factors after adjustment for total body fat, and for clinical purposes, most of the predictive power for men was contained in waist circumference, whereas for women, BMI and waist circumference were similarly predictive. Finally, even though the correlations between combined body fat parameters and risk factors explained only a portion of the variation in the latter, the average number of categorical metabolic risk factors increased progressively with increasing obesity. Hence, obesity seemingly has more clinical impact than revealed in these correlative studies.

Adult↗

PubMed2006

Urine composition in type 2 diabetes: predisposition to uric acid nephrolithiasis.

Type 2 diabetes is a risk factor for nephrolithiasis in general and has been associated with uric acid stones in particular. The purpose of this study was to identify the metabolic features that place patients with type 2 diabetes at increased risk for uric acid nephrolithiasis. Three groups of individuals were recruited for this outpatient study: patients who have type 2 diabetes and are not stone formers (n = 24), patients who do not have diabetes and are uric acid stone formers (UASF; n = 8), and normal volunteers (NV; n = 59). Participants provided a fasting blood sample and a single 24-h urine collection for stone risk analysis. Twenty-four-hour urine volume and total uric acid did not differ among the three groups. Patients with type 2 diabetes and UASF had lower 24-h urine pH than NV. Urine pH inversely correlated with both body weight and 24-h urine sulfate in all groups. Urine pH remained significantly lower in patients with type 2 diabetes and UASF than NV after adjustment for weight and urine sulfate (P < 0.01). For a given urine sulfate, urine net acid excretion tended to be higher in patients with type 2 diabetes versus NV. With increasing urine sulfate, NV and patients with type 2 diabetes had a similar rise in urine ammonium, whereas in UASF, ammonium excretion remained unchanged. The main risk factor for uric acid nephrolithiasis in patients with type 2 diabetes is a low urine pH. Higher body mass and increased acid intake can contribute to but cannot entirely account for the lower urine pH in patients with type 2 diabetes.

Adult↗

PubMed2006

Effect of vitamin E supplementation with and without hormone therapy on circulatory inflammatory markers in postmenopausal women.

OBJECTIVE: To investigate the effect of vitamin E with and without estrogen replacement therapy or hormone therapy (HT) on inflammatory markers in postmenopausal women. DESIGN: Prospective, observational study, followed by a randomized, prospective, double-blind study. SETTING: Healthy volunteers in an academic medical referral center in Dallas, Texas. PATIENT(S): Seventy-five postmenopausal healthy women, ages 40 to 65 years, with follicle-stimulating hormone (FSH) levels greater > or =30 mIU/mL and a serum estradiol level < or =30 pg/mL. INTERVENTION(S): After enrollment, all women were studied at baseline and received vitamin E for 4 weeks. They were then randomized from week 4 to week 12 to receive vitamin E in conjunction with conjugated equine estrogen (CEE) (0.625 mg), CEE (0.625 mg) plus medroxyprogesterone acetate (MPA) (2.5 mg), or placebo. MAIN OUTCOME MEASURE(S): Change from baseline and between groups effects of vitamin E with and without estrogen or hormone therapy on seven circulatory inflammatory markers in postmenopausal women. RESULT(S): Vitamin E levels increased to a similar extent in all three groups compared with baseline at weeks 4 and 12. Vitamin E increased serum interleukin-6 levels. Combination CEE plus MPA significantly increased C-reactive protein levels. However, there were no consistent statistically significant effects on six other inflammatory markers. CONCLUSION(S): Vitamin E attenuated C-reactive protein increases in postmenopausal women treated with estrogen replacement therapy but not with HT. Because there was no other persistent effect on six additional inflammatory markers, it can be concluded that vitamin E and HT do not play a major role in promoting a change in cardiovascular inflammatory markers.

Adult↗

PubMed2006

Effect of high and low calcium diets on stone forming risk during liberal oxalate intake.

PURPOSE: Recent studies suggest that a high calcium diet protects against calcium oxalate stone formation. We compared the effect of high and low calcium diets on urinary saturation of calcium oxalate during liberal oxalate intake. MATERIALS AND METHODS: A total of 10 healthy subjects (5 male, 5 female) participated in a 2-phase, randomized, crossover study comparing high (1,000 mg daily) and low (400 mg daily) calcium intake on a liberal oxalate diet (200 mg daily). During each phase subjects adhered to an instructed diet for 3 days followed by a controlled, metabolic diet for 4 days. Blood and 24-hour urine specimens collected on the last 2 days of each phase were analyzed for serum biochemistry studies and stone risk factors, respectively. RESULTS: Urinary calcium was higher (mean +/- SD 171 +/- 64 vs 124 +/- 49 mg daily, p = 0.002) and oxalate was lower (25 +/- 4.8 vs 27 +/- 4 mg daily, p = 0.02) on the high vs low calcium diet. Overall, the urinary relative saturation ratio of calcium oxalate was higher on the high compared with the low calcium diet (3.3 vs 2.5, p <0.0001) even after adjusting for confounding variables. CONCLUSIONS: In normal subjects urinary saturation of calcium oxalate was higher on a high calcium diet than a low calcium diet during liberal oxalate intake because the decrease in urinary oxalate did not overcome the effect of increased calcium. A high calcium diet during liberal oxalate intake may pose an increased risk of calcium oxalate stone formation.

Adult↗

PubMed2006

Insulin therapy, glycemic control, and cardiovascular risk factors in young Latin Americans with type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes has been linked to an increased risk of cardiovascular (CV) disease, but this risk has not been well documented in young patients, especially of Latin American descent. Also, the potential CV benefits of insulin therapy have not been evaluated in young patients with type 2 diabetes. The objectives of this study were to determine any gender-related difference in the presence of CV risk factors in young Latin Americans with poorly controlled type 2 diabetes and the effect of intensive insulin therapy on these CV risk factors. METHODS AND RESULTS: Fifty-seven Latin American patients with type 2 diabetes between the ages 18 and 45 years were evaluated at baseline. All women were premenopausal and had regular menstrual periods. The mean body mass index (BMI) was > 30 kg/m2 in both genders. Percent body fat, percent hemoglobin A1c, and lipoprotein profiles were similar between genders. Highly sensitive C-reactive protein (CRP) levels were elevated and similar between genders (p = .4). Leukocyte adhesion molecules (intercellular adhesion molecule 1, vascular adhesion molecule 1, E-selectin) and monocyte chemoattractant protein 1 were elevated, whereas adiponectin levels were below normal in both gender groups. Urinary albumin excretion was similar between genders and did not show any relationship with any of the variables. In women, there was a direct relationship between waist circumference and high-sensitivity CRP levels (rho = .53, p = .01). No other significant relationships were observed. Eighteen Latin American patients with type 2 diabetes completed up to 104 weeks of post-intervention with insulin monotherapy. In these patients, glycemic, lipoprotein, and anthropometric measurements were obtained every 12 weeks. Highly sensitive CRP, leukocyte adhesion molecules, and urinary albumin excretion, among other tests, were obtained every 52 weeks. At 52 and 104 weeks, body weight, BMI, waist circumference, and percent body fat increased in a parallel and significant manner. Despite a significant decrease in percent hemoglobin A1c (22.2%; p = < .0001), lipid and lipoprotein profiles, highly sensitive CRP, leukocyte adhesion molecules, and other nontraditional CV risk factors did not change significantly. CONCLUSIONS: In young, obese, Latino type 2 diabetic patients, improvement in glycemic control with insulin monotherapy was not associated with a parallel improvement in markers of vascular inflammation. Premenopausal Latino women with uncontrolled type 2 diabetes have CV risks comparable to Latino diabetic men of the same age. Obesity and underlying insulin resistance may counteract the potential CV benefits associated with insulin therapy in lean diabetic patients. Weight loss could be a potential therapeutic modality to improve CV risk in Latino type 2 diabetic patients, especially women.

Adolescent↗

PubMed2005

Effect of cranberry juice consumption on urinary stone risk factors.

PURPOSE: We evaluated the effect of cranberry juice on urinary stone risk factors. MATERIALS AND METHODS: A total of 12 normal subjects and 12 calcium oxalate stone formers underwent 2, 7-day phases of study in random order while on a controlled metabolic diet. Subjects ingested 1 l of cranberry juice (CBJ) daily in 1 phase and 1 l of deionized water in the other phase. On the last 2 days of each phase 2, 24-hour urine collections and blood samples were obtained for stone risk factors and serum chemistries. RESULTS: No significant differences were found between normal subjects and stone formers in response to CBJ and, therefore, the groups were combined. CBJ significantly increased urinary calcium (from 154 to 177 mg per day, p =0.0008) and urinary oxalate (from 26.4 to 29.2 mg per day, p =0.04), thereby increasing urinary saturation of calcium oxalate by 18%. Urinary citrate was unchanged and urinary magnesium increased slightly. Urinary pH decreased (from 5.97 to 5.67, p =0.0005), and urinary ammonium, titratable acidity and net acid excretion increased during CBJ ingestion. Urinary uric acid decreased (from 544 to 442 mg per day, p <0.0001) as did serum uric acid. Thus, the urinary saturation of brushite and monosodium urate was reduced by CBJ but the amount of undissociated uric acid increased. CONCLUSIONS: CBJ exerts a mixed effect on urinary stone forming propensity. It reduces urinary pH likely by providing an acid load and decreases urinary uric acid perhaps by retarding urate synthesis. Overall CBJ increases the risk of calcium oxalate and uric acid stone formation but decreases the risk of brushite stones.

Acid-Base Equilibrium↗

PubMed2005

ENPP1/PC-1 K121Q polymorphism and genetic susceptibility to type 2 diabetes.

Genetic susceptibility modulates the impact of obesity on risk for type 2 diabetes. The present study evaluates the role of ENPP1 K121Q polymorphism in prediction of type 2 diabetes in three populations that differ in susceptibility to diabetes and environmental exposure. The three cohorts included 679 nonmigrant South Asians living in Chennai, India (223 with type 2 diabetes); 1,083 migrant South Asians living in Dallas, Texas (121 with type 2 diabetes); and 858 nonmigrant Caucasians living in Dallas, Texas (141 with type 2 diabetes). Patients with type 2 diabetes were included in these cohorts if they had diabetes onset before the age of 60 years. The prevalence of subjects carrying the polymorphic ENPP1 121Q allele was 25% in the nondiabetic group and 34% in the diabetic group of South Asians living in Chennai (P = 0.01). The prevalence in the nondiabetic and diabetic groups were 33 and 45% (P = 0.01) for the South Asians living in Dallas and 26 and 39% (P = 0.003) for the Caucasians. Although further replication studies are necessary to test the validity of the described genotype-phenotype relationship, our study supports the hypothesis that ENPP1 121Q predicts genetic susceptibility to type 2 diabetes in both South Asians and Caucasians.

Adult↗

PubMed2005

Effect of a high-carbohydrate versus a high--cis-monounsaturated fat diet on blood pressure in patients with type 2 diabetes.

OBJECTIVE: To investigate whether blood pressure is different in type 2 diabetic patients on a diet rich in carbohydrates versus a diet rich in cis-monounsaturated fatty acids. Data on the dietary effects on these diets' glucose and lipid metabolism have been previously published. RESEARCH DESIGN AND METHODS: The study compared the effect of feeding 42 type 2 diabetic patients a carefully controlled isoenergic high-carbohydrate (high-carb; 55% energy as carbohydrate, 30% as fat, and 10% as monounsaturated fat) and high-monounsaturated fat (high-mono; 45% energy as fat, 25% as monounsaturated fat, and 40% as carbohydrate) diet for 6 weeks each in a four-center, randomized, cross-over study on blood pressure. Twenty-one patients continued the diet they received during the second phase for an additional 8 weeks. RESULTS: According to repeated-measures ANOVA, blood pressure during the last 3 days of each phase was similar after 6 weeks of the high-carb and high-mono diets (systolic blood pressure: 128 +/- 16 vs. 127 +/- 15 mmHg, P = 0.9; diastolic blood pressure: 75 +/- 7 vs. 75 +/- 8 mmHg, P = 0.7). However, after 14 weeks of the high-carb diet (n = 13), there was a significant increase in blood pressure compared with 6 weeks of the high-mono diet (systolic blood pressure: 132 +/- 13 vs. 126 +/- 11 mmHg, P = 0.04; diastolic blood pressure: 83 +/- 6 vs. 76 +/- 7 mmHg, P = 0.002). After 14 weeks of the high-mono diet (n = 8), the reduction in blood pressure was not significant compared with 6 weeks of the high-carb diet (systolic blood pressure: 118 +/- 14 vs. 121 +/- 16 mmHg, P = 0.4; diastolic blood pressure: 71 +/- 8 vs. 75 +/- 10 mmHg, P = 0.3). CONCLUSION: Although the exchange of carbohydrates with monounsaturated fats may not affect blood pressure in the short term, long-term consumption of a high-carbohydrate diet may modestly raise blood pressure in type 2 diabetic patients.

Aged↗

PubMed2004

Elucidation of factors determining formation of calcium phosphate stones.

PURPOSE: In this study we compared the effect of the urinary concentration of calcium with that of oxalate on the urinary relative saturation ratio (RSR) of calcium oxalate and brushite in patients with pure or mixed calcium phosphate stones. MATERIALS AND METHODS: A retrospective data analysis was performed of urinary stone risk analysis in 133 patients with pure or mixed calcium phosphate stones (30% or greater). Correlation was sought between stone events and urinary stone risk factors, and between brushite and urinary constituent RSRs before and after adjustment for variables. RESULTS: The formation rates of total events and stone surgeries weakly but significantly correlated with RSR urinary brushite (total events r = 0.22, p = 0.01) but not with RSR calcium oxalate. Urinary RSR brushite significantly correlated positively with urinary calcium (r = 0.67, p <0.0001), phosphorus and pH. After adjustment RSR brushite inversely correlated with citrate (r = -0.3, p = 0.0006). However, it did not correlate with oxalate. CONCLUSIONS: In stone formers with calcium phosphate or mixed calcium oxalate-calcium phosphate stones the stone formation rate depends on the urinary saturation of brushite but not of calcium oxalate. RSR brushite is determined by the urinary concentration of calcium, phosphate, citrate and pH but not by oxalate. Hypercalciuria should be controlled in patients with idiopathic calcareous renal calculi who form stones of pure or mixed calcium phosphate.

Adult↗

PubMed2004

Association of urinary pH with body weight in nephrolithiasis.

BACKGROUND: The prevalence of kidney stone disease in the United States is progressively increasing, paralleling the growing rate of obesity. Uric acid nephrolithiasis, a condition associated with a low urinary pH, has been linked to obesity and insulin resistance. Based on these observations, we hypothesized that urinary pH may be inversely associated to body weight in nephrolithiasis. METHODS: Data were retrieved from 4883 patients with nephrolithiasis who underwent ambulatory evaluation at two established stone clinics in Dallas and Chicago. The patients collected 24-hour urine samples on an outpatient basis, while avoiding any drug that could alter urinary pH. Patients were divided in increasing sextiles of body weight, and urinary pH was adjusted for urinary creatinine and for age. RESULTS: Urinary pH had a strong, graded inverse association with body weight. Urinary creatinine and age were both found to be significant covariates of urinary pH, while gender was not a significant independent variable after adjustment for urinary creatinine. Mean 24-hour urinary pH, adjusted for age and urinary creatinine, were 6.09, 6.04, 6.01, 5.99, 5.97, and 5.91 for sextiles of body weight in increasing order from Dallas (P for linear trend <0.0001), and 6.18, 6.10, 6.04, 6.02, 5.97, and 5.88 for the sextiles from Chicago (P for linear trend <0.0001). CONCLUSION: We conclude that urinary pH is inversely related to body weight among patients with stones. The results confirm the previously proposed scheme that obesity may sometimes cause uric acid nephrolithiasis by producing excessively acid urine due to insulin resistance.

Adult↗

PubMed2004

Rapid Communication: relative effect of urinary calcium and oxalate on saturation of calcium oxalate.

BACKGROUND: The study compared the effect of urinary calcium with that of oxalate on urinary saturation [relative saturation ratio (RSR)] of calcium oxalate. METHODS: A retrospective data analysis was conducted on urinary stone risk analysis from 667 patients with predominantly calcium oxalate stones. Urinary RSR of calcium oxalate was individually calculated using Equil 2. A "theoretical" curve of the relationship between urinary RSR of calcium oxalate and concentration of calcium or oxalate was obtained at two stability constants for calcium oxalate complex, while varying calcium or oxalate and using group mean values for urinary constituents. RESULTS: At the stability constant of 7.07 x 10(3), the increase in RSR of calcium oxalate was less marked with calcium than with oxalate. However, at the stability constant of 2.746 x 10(3) from the Equil 2 that is considered the "gold standard," calcium and oxalate were equally effective in increasing RSR of calcium oxalate. The above theoretical curves (relating RSR with calcium or oxalate) were closely approximated by the actual curves constructed with data from individual urine samples. Urinary saturation of calcium oxalate was equally dependent on urinary concentrations of calcium and oxalate (r= 0.75 unadjusted and 0.57 adjusted for variables, and P < 0.0001 for calcium; r= 0.73 unadjusted and 0.60 adjusted, P <0.0001 for oxalate). CONCLUSION: Among calcium oxalate stone-formers, urinary calcium is equally effective as urinary oxalate in increasing RSR of calcium oxalate.

Adult↗

PubMed2004

Acute post-gastric reduction surgery (APGARS) neuropathy.

BACKGROUND: A variety of neurologic complications have been reported after weight loss surgery. Recently, a new term was introduced to describe cases of postoperative polyneuropathy - acute post-gastric reduction surgery (APGARS) neuropathy, a polynutritional, multisystem disorder characterized by protracted postoperative vomiting, hyporeflexia, and muscular weakness. The incidence, associations, and prognosis of this disorder have not been precisely defined. METHODS: A questionnaire about features of APGARS was mailed to all members of the ASBS. Surgeons were asked about their surgical and bariatric experience. Respondents were asked to report on specific cases where APGARS may have been present. They were also asked to report the patient's diagnosis and which operation the patient had undergone. RESULTS: Of the 808 questionnaires, 257 were returned for a response-rate of 31.8%. The mean years in general surgical practice and in bariatric surgery were 15.3 +/- 10.3 and 7.5 +/- 7.4. A total of 168010 bariatric cases were performed by all respondents. 109 cases of neuropathy were described. 99 cases were believed to represent APGARS (weakness with hyporeflexia and/or vomiting). Vitamin B and/or thi12 amine deficiency were present in 40 (40%); 18 cases resolved. 9 of 17 cases with B(12) deficiency resolved; 12 of 29 cases with thiamine deficiency resolved; and 3 of 6 cases with both deficiencies resolved. Vitamin deficiencies were not noted in 59 (60%), of which 30 resolved. The most common diagnoses were Wernicke's encephalopathy, thiamine deficiency, and Guillain-Barré Syndrome. The most common operation performed was gastric bypass. CONCLUSIONS: The incidence of APGARS in this survey was 5.9 cases per 10000 operations. Given the potentially reversible nature of APGARS, surgeons should be aware of the findings and treatment.

Acute Disease↗

PubMed2004

Nutrient intake and diet quality in patients with systemic lupus erythematosus on a culturally sensitive cholesterol lowering dietary program.

OBJECTIVE: To evaluate the effect of a culturally sensitive cholesterol lowering dietary program on energy, protein, fiber, vitamin and mineral intake, diet quality, and hemoglobin levels in patients with systemic lupus erythematosus (SLE). METHODS: Seventeen patients with SLE were randomized to a Step II diet intervention group or a control group for 12 weeks. The diet intervention was made up of weekly group sessions during the first 6 weeks followed by telephone counseling every 2 weeks for the last 6 weeks. Food intake was assessed by 3-day food record at baseline, 6, and 12 weeks. Diet quality was assessed by expressing the nutrients as a percentage of the Dietary Reference Intakes of the US National Academy of Sciences, or as a percentage of the nutrient guidelines by the National Cholesterol Education Program, Adult Treatment Panel III. Between- and within-group changes in nutrient intakes were assessed by repeated measures ANOVA. RESULTS: The changes in nutrient intakes were not significantly different between the groups for any of the nonfat nutrients except vitamin B12 (p = 0.05), which decreased in the diet group and increased in the control group. Within-group analysis showed a significant reduction (p = 0.0003 to 0.02) in the diet group in energy and sodium intake at 6 and 12 weeks and B12 intake at 12 weeks compared to the respective baseline values (28-32%, 37-41%, and 43%, respectively). Sodium intake decreased to 66-71% of the total sodium allowance (< 2400 mg per day) in the diet group. The intervention was successful in maintaining adequate intakes or even increasing intakes of most nutrients except B12, dietary fiber, folate, calcium, and iron, which were slightly higher or below 67% of the Dietary Reference Intakes or other dietary guidelines. Anemia, as assessed by hemoglobin levels, was present throughout the study and did not correlate with iron intake. CONCLUSION: This culturally sensitive cholesterol reducing diet program was successful in decreasing sodium intake and maintaining adequate intakes of most nutrients except B12, dietary fiber, iron, calcium, and folate. Future intervention studies in patients with SLE need to pay special attention to these nutrients and the presence of anemia.

Adult↗

PubMed2003

Predictive value of kidney stone composition in the detection of metabolic abnormalities.

PURPOSE: To determine if kidney stone composition can predict the underlying medical diagnosis, and vice versa. METHODS: We studied 1392 patients with kidney stones who underwent a complete ambulatory evaluation and who submitted one or more stones for analysis. We ascertained the associations between medical diagnosis and stone composition. RESULTS: The most common kidney stones were composed of calcium oxalate (n = 1041 patients [74.8%]), mixed calcium oxalate-calcium apatite (n = 485 [34.8%]), and calcium apatite alone (n = 146 [10.5%]). The most common medical diagnoses were hypocitraturia (n = 616 patients [44.3%]), absorptive hypercalciuria (n = 511 [36.7%]), and hyperuricosuria (n = 395 [28.4%]). Calcium apatite and mixed calcium oxalate-calcium apatite stones were associated with the diagnoses of renal tubular acidosis and primary hyperparathyroidism (odds ratios >/=2), but not with chronic diarrheal syndromes. As the phosphate content of the stone increased from calcium oxalate to mixed calcium oxalate-calcium apatite, and finally to calcium apatite, the percentage of patients with renal tubular acidosis increased from 5% (57/1041) to 39% (57/146), and those with primary hyperparathyroidism increased from 2% (26/1041) to 10% (14/146). Calcium oxalate stones were associated with chronic diarrheal syndromes, but not with renal tubular acidosis. Pure and mixed uric acid stones were strongly associated with a gouty diathesis, and vice versa. Chronic diarrheal syndromes and uric acid stones were associated with one another, and brushite stones were associated with renal tubular acidosis. As expected, there was a very strong association between infection stones and infection, and between cystine stones and cystinuria. CONCLUSION: Stone composition has some predictive value in diagnosing medical conditions, and vice versa, especially for noncalcareous stones.

Acidosis, Renal Tubular↗

PubMed2003

Effect of gonadotropin-releasing hormone agonist and medroxyprogesterone acetate on calcium metabolism: a prospective, randomized, double-blind, placebo-controlled, crossover trial.

OBJECTIVE: The purpose of this study was to prospectively compare the effectiveness of administering medroxyprogesterone acetate (MPA; 20 mg/d) in either the first (protocol A) or last (protocol B) 12-week period as well as a 6-month course of the GnRH agonist (GnRH-a; leuprolide acetate; 1 mg/d, SC) on calcium (Ca) metabolism. DESIGN: Prospective, randomized, double-blind, placebo-controlled, crossover trial. SETTING: Clinical research center, university hospital. PATIENT(S): Twenty women were randomized into protocol A or B, received either MPA or placebo along with GnRH-a, and were then crossed over at 12 weeks to placebo or MPA, for the final 12-week interval of GnRH-a therapy. INTERVENTION(S): Collection of serum and urine samples and measurement of bone density. Sex hormone, calcitropic hormone, and bone density studies were performed at baseline and at 12 and 24 weeks. RESULT(S): In both protocol A and B, LH and E(2) levels declined by 79%-81% and 83%-90% of the baseline, respectively, at 12 and 24 weeks. Serum Ca, phosphorus, alkaline phosphatase, and osteocalcin; 2-h fasting and 24-h urinary Ca excretion; and urinary hydroxyproline levels all increased significantly during GnRH-a treatment alone. Estimated Ca balance decreased significantly during GnRH-a treatment alone. The addition of MPA attenuated the increases in phosphorus, alkaline phosphatase, osteocalcin, and 2-h fasting and 24-h urinary Ca excretion, and the decrease in estimated Ca balance. Comparison of phase order demonstrated that MPA prevented 24-h urinary Ca excretion and urinary hydroxyproline loss and decline in estimated Ca balance when it was added back during the second 12 weeks (protocol B) but not during the first 12 weeks (protocol A). CONCLUSION (S): We conclude that sequential MPA appears to reverse in part the negative effects of GnRH-a on calcitropic hormones and estimated Ca balance.

Adult↗

PubMed2003

Effect of dietary calcium on stone forming propensity.

PURPOSE: Epidemiological studies have reported that high calcium diet protects against kidney stone formation in normal subjects. This metabolic study was designed to elucidate the physiological and physicochemical effects conferring this apparent protection. MATERIALS AND METHODS: A total of 21 normal volunteers underwent 2 phases of study in a crossover, randomized design, wherein they consumed constant metabolic diets that matched the estimated highest and lowest quintiles of calcium intake from published epidemiological studies. RESULTS: Urinary calcium was significantly greater on the high calcium diet (148 +/- 55 versus 118 +/- 43 mg. daily, p <0.01, p <0.01) but urinary oxalate did not differ between diets. There was no difference in relative saturation ratio of calcium oxalate between the 2 diets. The high calcium diet significantly increased saturation of brushite and decreased that of uric acid. Due to the other differences between the diets (more fluid, potassium, magnesium and phosphate in the high calcium diet), the high calcium diet also increased 24-hour urinary volume, potassium, phosphorus, pH and citrate. After adjustment of these confounding variables, the high calcium diet significantly increased relative saturation ratio of calcium oxalate by 24%. CONCLUSIONS: High calcium diet from published epidemiological studies does not alter the propensity for calcium oxalate crystallization in normal subjects despite increased urinary calcium and unaltered urinary oxalate because of the greater amounts of ingested fluid, potassium and phosphate. However, high calcium intake alone, without concomitant changes in the diet, poses a modest risk for calcium stone formation.

Adult↗

PubMed2002

Pathophysiologic basis for normouricosuric uric acid nephrolithiasis.

BACKGROUND: Low urinary pH is the commonest and by far the most important factor in uric acid nephrolithiasis but the reason(s) for this defect is (are) unknown. Patients with uric acid nephrolithaisis have normal acid-base parameters according conventional clinical tests. METHODS: We studied steady-state plasma and urinary parameters of acid-base balance in subjects with normouricosuric pure uric acid stones. We also tested the ability of these subjects to excrete ammonium in response to an acute acid load. We compared these parameters in patients with pure uric acid stones to patients with mixed uric acid/calcium oxalate stones, pure calcium stones, and normal volunteers. RESULTS: Pure uric acid stone formers have a much higher incidence of either diabetes or glucose intolerance. After equilibration to a control diet, patients with uric acid stones have lower urinary pH and they excrete less of their acid as ammonium. This is compensated by higher titratable acidity and hypocitraturia. Despite their low baseline urinary pH, uric acid stone formers further acidify their urine after an acid load because of a severely impaired ammonia excretory response. Their characteristics are significantly different from normal volunteers and pure calcium stone formers. Patients with mixed uric acid/calcium stones exhibit intermediate characteristics. CONCLUSION: We propose that certain patients with normouricosuric uric acid nephrolithiasis have a renal acidification disease. The primary defect lies in renal ammonium excretion, which may be linked to the insulin-resistant state. Although net acid excretion is maintained at the expense of increased titratable acidity and to some degree hypocitraturia, the compromise is acid urine pH and may result in uric acid nephrolithiasis.

Adult↗