Inadequacy of Dialysis, Chronic Inflammation and Malnutrition in Nigerian Patients on Chronic Hemodialysis

Purpose

To identify the extent of underdialysis, chronic inflammation and malnutrition and their interrelationships in Nigerian hemodialysis patients.

Methods

In a prospective study including 10 adult patients, (6 men, 4 women) on hemodialysis in North Central Nigeria, malnutrition was assessed by body mass index (BMI), serum albumin and prealbumin, and bioimpedance (BIA) pre-and post dialysis, inflammation was evaluated by C-reactive protein (CRP) and adequacy of dialysis was judged by frequency of the hemodialysis sessions and Kt/V urea.

Results

Post-dialysis BMI was 21.3 (19.9, 24.3) kg/m2 (< 20 kg/m2 in 4 patients), serum albumin 31.5 (24.0, 32.0) g/L (< 30.0 g/L in 5), serum pre-albumin 25.2 (15.3, 31.1) mg/dL (< 18.0 mg/dL in 4), serum CRP 4.8 (1.2, 11.5) mg/dL (> 1.0 mg/dL in 8), phase angle 4.2 (3.7, 5.1)° (< 3° in 3) and body fat deficit was diagnosed by BIA in 4 patients. Weekly frequency of dialysis was 3 times in 2 patients, twice in 1 and ≤1 time in 7. Single-pool Kt/V urea was 0.81 (0.68, 0.95, <1.2 in 9 patients and > 1.2 in one patient receiving dialysis only twice weekly). By combined frequency of dialysis and Kt/V urea values, no patient received an adequate dose of dialysis and, indeed, all patients had overt symptoms of uremia. Low body weight, low serological and BIA nutrition indices, and high CRP levels occurred in the same patients. Patients on dialysis for > 1 year had worse nutrition indices than those on dialysis for < 1 year.

Conclusions

Underdialysis was universal, while poor nutrition and chronic malnutrition were found in the majority of the small number of patients studied. These three adverse conditions, which were interlinked, may be common in Nigerian hemodialysis patients, because their underlying socioeconomic causes are widespread. (Int J Artif Organs 2006; 29: 1067–73)

Assessment of the vitamin B12 status of pregnant women in Nigeria using plasma holotranscobalamin

Maternal vitamin B12 deficiency during pregnancy is an independent risk factor for neural tube defects and other neurological problems in infants. We determined the vitamin B12 status of 143 pregnant women in Nigeria representing all trimesters who presented to an antenatal clinic in Jos, Nigeria, using holotranscobalamin II levels (holoTCII), which is a measure of the vitamin B12 that is available for uptake into tissues. The holoTCII concentration ranged from 13 to 128 pmol/L. Using a cutoff of 40 pmol/L, 36% of the women were classified as vitamin B12-deficient. HoloTCII concentrations correlated negatively with plasma homocysteine levels (r = −0.24, P = 0.003) and positively with red blood cell folate concentrations (r = 0.28, P < 0.001). These data underscore the importance of supplementing pregnant women in Nigeria with vitamin B12 in order to ensure adequate vitamin B12 status and decrease the risk for neural tube defects.

Low docosahexaenoic acid in the diet and milk of American Indian women in New Mexico

A recent finding of low levels of docosahexaenoic acid (DHA) in the milk of lactating Hispanic and non-Hispanic white women in New Mexico prompted a study of the DHA content of the breast milk and diets of American Indian women in the state. Nineteen urban American Indian women (18 to 40 years) who had been lactating for 1 to 6 months and who were attending clinics at the University of New Mexico Hospital were enrolled in a cross-sectional study that was conducted between June 2005 and February 2009. Descriptive statistics and correlations were performed. The mean fat content of the breast milk was 4.67±1.9 g/dL and the mean DHA proportion of the milk fat was 0.097%±0.035%, which is a low value relative to international norms. The low DHA content of the milk could be accounted for by the women's low dietary intake of DHA (median=30 mg). The DHA percentage in the women's milk fat was positively correlated with dietary intake of DHA (r=0.67; P<0.001). This study shows that the DHA content of the breast milk of urban American Indian women attending clinics at a university hospital in New Mexico is well below levels widely acknowledged as being healthful for infants who rely mainly on breast milk for their supply of DHA.

Subclinical vitamin B12 deficiency in pregnant women attending an antenatal clinic in Nigeria

SUMMARY

Inadequate vitamin B12 status in a pregnant woman increases the risk for adverse maternal and fetal outcomes. The use of serum vitamin B12 concentration alone to assess vitamin B12 status in pregnant women is unreliable because of the decrease in serum vitamin B12 levels in normal pregnancy. The combination of serum vitamin B12 and methylmalonic acid (MMA) concentrations may provide a better estimate of vitamin B12 status. We obtained blood samples from 98 pregnant women in the third trimester at an antenatal clinic in Jos, Nigeria. All subjects were taking iron and folate supplements. Twelve of the subjects had a serum vitamin B12 concentration <148 pmol/l and 18 subjects had a serum MMA level >271 nmol/l. Using a combination of low serum vitamin B12 and elevated MMA concentrations, eight subjects were classified as having subclinical vitamin B12 deficiency. Because of the potential harmful consequences of vitamin B12 deficiency in pregnant women, it would be advisable to add vitamin B12 supplements to the existing regimen of folate and iron supplements currently provided to pregnant women in Nigeria.

Assessment of the bone quality of black female athletes using quantitative ultrasound

AIM

The mean daily calcium intake of adult Nigerians is reportedly low, and animal studies have shown that exercise-induced changes in the bones of growing mice are gender specific. We therefore sought to describe calcaneal broadband ultrasound attenuation (BUA), speed of sound (SOS), stiffness index (SI) and SI-based T-scores in a cohort of Nigerian female athletes; to assess the correlation of SI with energy expenditure; and to compare mean SI values between sports.

METHODS

We recruited 52 female athletes in 10 sporting categories, and recorded their anthropometric data. Activity levels were estimated using a questionnaire. Bone density was assessed using calcaneal ultrasound.

RESULTS

The mean age of athletes was 21+/-4 years (range 15-39 years). The mean body mass index (BMI) was 22.0+/-3.5 kg/m2, and was not different between the sub-group of footballers/runners (21.3+/-1.7 kg/m2) and other athletes (23.1+/-4.8 kg/m2, P=0.06). The mean energy expenditure was 32.2+/-9.5 kcal/kg/ day, and was not different between the sub-group of footballers/runners (30.8+/-9.2 kcal/kg/day) and other athletes (34.3+/-9.7 kcal/kg/day, P=0.19). The mean BUA of the athletes was 135+/-14 dB/MHz, the mean SOS was 1597+/-13 m/s, the mean SI was 118+/-15, and the median SI-based T-score was +1.1 (-1.6 to +3.53). The means of all ultrasound parameters were not significantly different between footballers/runners and other sportswomen.

CONCLUSION

Consistent physical training may improve calcaneal SI of black females by one, and potentially by as much as three T-score units. Training intensity, rather than the qualitative aspects of a sport, appears to be a major determinant of SI in female Nigerian athletes.

Assessment of the bone quality of black male athletes using calcaneal ultrasound: a cross-sectional study

BACKGROUND

Lifestyle, genetics and environmental factors are established determinants of bone density. We aimed to describe the bone characteristics of competitive top-ranked Nigerian male athletes using calcaneal ultrasound and to assess whether intensive training promotes higher bone density in an environment with reportedly low calcium intake; to compare the bone characteristics of footballers with runners and other sportsmen; and to assess the correlation of stiffness index (SI) with activity level, since energy expenditure correlates with length of training and by extension, magnitude of skeletal loading.

METHODS

We recruited 102 male athletes: these included football (n = 68), running (n = 15), handball (n = 7), taekwando (n = 6), cycling (n = 2), judo (1), badminton (1) and high jump (1). Anthropometric data were first recorded on a structured form and energy expenditure was indirectly estimated with a validated questionnaire. Bone density was assessed using the Lunar Achilles+ calcaneal ultrasonometer.

RESULTS

The mean age of athletes was 25 +/- 6 years. The means of BMI and energy expenditure were 21.9 +/- 2.0 kg/m2 and 35.0 +/- 13.7 kcal/kg/day, respectively. Footballers were younger (p < 0.001) and heavier (p < 0.001) than runners. Football was a significant determinant of BUA independent of age, BMI and energy expenditure (p = 0.001). Football was also a significant determinant of SOS independent of age, height, weight and BMI (p < 0.001). The mean SI was 127 +/- 16 and the median T-score was 0.82 (-1.88, 3.35). The mean SI of footballers (130 +/- 15), runners (130 +/- 12) and other sportsmen (115 +/- 18) differed significantly (p = 0.001). Multivariate analyses revealed that football (p < 0.001) and running (p < 0.001) were significant determinants of SI independent of age and BMI. Footballers when compared with other sportsmen had a higher mean SI independent of age and BMI (p < 0.001). Age was not correlated with SI. The median T-score of footballers, 0.94 (-1.0, 3.35) was higher than that of other sportsmen.

CONCLUSION

Repetitive skeletal loading at the heel has the potential to improve bone density in black male athletes. The magnitude of increase may be higher in medium impact sports such as soccer and running compared with low or non-impact sports such as judo or taekwando, and is independent of age and BMI. However, future longitudinal data will be required to support our observations.

The prescription of peritoneal dialysis

In addition to the maintenance of normal extracellular electrolyte composition, the prescription of continuous peritoneal dialysis (CPD) should address four other specific issues: (i) prevention of uremia by achievement of adequate clearance of azotemic substances, (ii) prevention of progressive expansion of the extracellular volume by adequate peritoneal ultrafiltration, (iii) prevention of loss of residual renal function, and (iv) prevention of deterioration of the peritoneal membrane structure and function. Urea clearance, in the form of Kt/V(Urea), is the index of removal of azotemic substances proposed by current guidelines. The target total (renal plus peritoneal) Kt/V(Urea) is >or=1.7 weekly. To provide the desired peritoneal Kt/V(Urea) (K(p)t/V(Urea)), the prescription of peritoneal dialysis must provide a daily drain volume (Dv) defined by the clearance equations as Dv = V x (K(p)t/V(Urea))/(D/P(Urea)), where V is body water obtained from published anthropometric formulas, K(p)t/V(Urea) = (1.7 - renal Kt/V(Urea))/7 and D/P(Urea) is the dialysate-to-plasma urea concentration ratio at the dwell time prescribed. Computer programs obtain the relevant D/P(Urea) values from formal studies of peritoneal transport. In the absence of these studies (for example, at initiation of CPD), D/P(Urea) values can be obtained from published studies with similar dwell times. Body size, indicated by V, is the major determinant of the K(p)t/V(Urea) limit provided by a given CPD schedule. Other obstacles to achievement of adequate urea clearance are created by poor patient compliance, inaccuracies of the anthropometric formulas estimating V, and mechanical complications of CPD that lead to retention of dialysate in the body. The main requirements for the prescription of adequate ultrafiltration are knowledge of the individual peritoneal transport characteristics, monitoring of urinary volume, and restriction of dietary sodium intake. Excessive dietary sodium intake is the major cause of extracellular volume expansion in CPD. Ideally, sodium intake should be kept at the level of total (peritoneal plus renal) sodium removal. Preventing the loss of residual renal function involves avoidance of nephrotoxic influences in the form of medications, radiocontrast agents, urinary obstruction and infection, and possibly other influences, such an elevated calcium-phosphorus product and anemia. Use of the lowest dialysate dextrose concentration that will allow adequate ultrafiltration is currently the most widespread practical measure of prevention of peritoneal membrane deterioration. Formulation of biocompatible dialysate is a major ongoing research effort and may greatly enhance the success of CPD in the future.

Hydration abnormalities in Nigerian patients on chronic hemodialysis

The state of hydration affects the outcomes of chronic dialysis. Bioelectrical impedance analysis (BIA) provides estimates of body water (V), extracellular volume (ECFV), and fat-free mass (FFM) that allow characterization of hydration. We compared single-frequency BIA measurements before and after 14 hemodialysis sessions in 10 Nigerian patients (6 men, 4 women; 44+/-7 years old) with clinical evaluation (weight removed during dialysis, presence of edema) and with estimates of body water obtained by the Watson, Chertow, and Chumlea anthropometric formulas. Predialysis and postdialysis values of body water did not differ between BIA and anthropometric estimates. However, only the BIA estimate of the change in body water during dialysis (-0.8+/-2.9 L) did not differ from the corresponding change in body weight (-1.3+/-3.0 kg), while anthropometric estimates of the change in body water were significantly lower, approximately one-third of the change in weight. Bioelectrical impedance analysis correctly detected the intradialytic change in body water content (the ratio V/Weight) in 79% of the cases, while anthropometric formula estimates of the same change were erroneous in each case. Compared with patients with clinical postdialysis euvolemia (n=7), those with postdialysis edema (n=5) had higher values of postdialysis BIA ratios V/FFM (0.77+/-0.01 vs. 0.72+/-0.03, p<0.01) and ECFV/V (0.53+/-0.02 vs. 0.47+/-0.06, p<0.05), respectively. Bioelectrical impedance analysis appeared to underestimate body water and extracellular volume in a patient with massive ascites and bilateral pleural effusions. Anthropometric formulas are not appropriate for evaluating the state of hydration in patients on chronic hemodialysis. In contrast, BIA provides estimates of hydration agreeing with clinical estimates in the same patients, although it tends to underestimate body water and extracellular volume in patients with large collections of fluid in central body cavities.

Amino acid, mineral and fatty acid content of pumpkin seeds (Cucurbita spp) and Cyperus esculentus nuts in the Republic of Niger

Dried seeds and nuts are widely consumed by indigenous populations of the western Sahel, especially those who inhabit rural areas. In light of the need for quantitative information regarding the content of particular nutrients in these plant foods, we collected dried pumpkin (Cucurbita spp) seeds and nuts of Cyperus esculentus in the Republic of Niger and analyzed them for their content of essential amino acids, minerals and trace elements, and fatty acids. On a dry weight basis, pumpkin seed contained 58.8% protein and 29.8% fat. However, the lysine score of the protein was only 65% relative to the FAO/WHO protein standard. The pumpkin seed contained useful amounts of linoleic (92 microg/g dry weight) and the following elements (on a microg per g dry weight basis): potassium (5,790), magnesium (5,690), manganese (49.3), zinc (113), selenium (1.29), copper (15.4), chromium (2.84), and molybdenum (0.81), but low amounts of calcium and iron. Except for potassium (5,573 microg/g dry weight) and chromium (2.88 microg/g dry weight), the C. esculentis nuts contained much less of these same nutrients compared to pumpkin seeds. In conclusion, pumpkin seeds represent a useful source of many nutrients essential to humans. The data in this report should of practical value to public health officials in rural areas of sub-Saharan Africa.

Trans fatty acids and conjugated linoleic acids in the milk of urban women and nomadic Fulani of northern Nigeria

BACKGROUND

Trans fatty acids (TFAs) and conjugated linoleic acids (CLAs) are present in dairy products and human milk and can have detrimental and beneficial effects in humans. The content of TFAs and CLAs in milk is determined largely by the diet of the mother.

METHODS

We compared the proportions of TFAs and CLAs in the milk of rural Fulani in northern Nigeria who consume dairy products to that of women living in an urban center who consume little in the way of dairy products. Lactating Fulani women (n=41) and women residing in the city of Jos, Nigeria (n=41) were recruited into the study. We predicted that the milk of the Fulani pastoralists would contain higher amounts of TFAs and CLAs compared to their urban counterparts.

RESULTS

The mean total TFA proportions for the Fulani and urban women were 0.22% and 0.34%, respectively, and were not significantly different. The percentages of CLAs in milk fat were not different between rural and urban women (0.16% vs 0.14%). These TFA and CLA values were 4- to 10-fold lower than for milk of women elsewhere in the world.

CONCLUSIONS

The percentages of TFAs and CLAs in milk were not different between rural and urban dwellers in northern Nigeria whose diets differ greatly in the amounts of dairy products they contain. However, the fact that the percentages of TFAs and CLAs in the milk of Nigerian women were much lower than the percentages reported from other parts of the world may have implications for the long-term growth and development of infants in the northern Nigeria and elsewhere in the Western Sahel.

Maternal mortality among adolescent women in Jos, north-central, Nigeria

The adolescent maternal mortality ratio is high in Jos, north-central Nigeria. The main causes of maternal deaths among the adolescents were unsafe abortion, eclampsia and sepsis. The Hausa/Fulani ethnic group constituted the largest ethnic group of adolescent maternal deaths in our study. The risk factors for adolescent maternal mortality found in our study were illiteracy, non-utilisation of antenatal services and Hausa/Fulani ethnic group.

Factors contributing to maternal mortality in north-central Nigeria: a seventeen-year review

Maternal mortality ratio in Nigeria is one of the highest in the world. This paper reports a facility based study in north-central Nigeria to determine the magnitude, trends, causes and characteristics of maternal deaths before and after the launch of the Safe Motherhood Initiative in Nigeria, with a view to suggesting strategic interventions to reduce these deaths. The records of all deliveries and case files of all women who died during pregnancy and childbirth between January 1, 1985 and December 31, 2001, in the maternity unit of Jos University Teaching Hospital, Jos, Nigeria, were reviewed. Data collected were analysed for socio-biological variables including age, booking status, educational level, parity, ethnic group, marital status, mode of delivery, duration of hospital stay before death occurred, cause (s) of maternal deaths. There were 38,768 deliveries and 267 maternal deaths during the period under review, giving a maternal mortality ratio (MMR) of 740/ 100,000 total deliveries. The trend fluctuated between 450 in 1990 and 1,010/100.000 deliveries in 1994. The mean age of maternal death was 26.4 (SD 8.1) years. The greatest risk of MMR was among young teenagers (> 15 years) and older women (< 40 years). Parity-specific maternal mortality ratio was highest in the grand multiparous women. Unbooked as well as illiterate women were associated with very high maternal mortality ratio. The Hausa - Fulani ethnic group contributed the largest number (44%) by tribe to maternal mortality in our study. The major direct causes of deaths were haemorrhage (34.6%), sepsis (28.3%), eclampsia (23.6%) and unsafe abortion (9.6%). The most common indirect causes of death were hepatitis (18.6%), anaesthetic death (14.6%), anaemia in pregnancy (14.6%), meningitis (12.0%), HIV/AIDS (10.6%) and acute renal failure (8.0%). Seventy-nine percent of the maternal deaths occurred within 24 hours of admission. Most of the deaths were preventable. A regional-specific programme should be planned to reduce the deplorably high maternal mortality in north-central Nigeria.

Nutrient content of four edible wild plants from west Africa

Non-cereal plant foods in the Western Sahel of Africa contribute significantly to the diets of local residents, especially during periods of grain shortages. In this paper, we analyze four such plant foods including diyan kwakwa (nut of coconut palm, Cocos nucifera L.), muricin giginya (young shoot of Borassus aethiopum), tsamiya biri (fruit of the tree, Tamarindus indica), and yari (a mixture of lichens, mainly Rimelia reticulate) that grows on ebony trees (Diospyros mespiliformis). They were analyzed for their content of amino acids, fatty acids, and minerals. Although diyan kwakwa contained the highest protein content (27.1%), its protein quality fell below the WHO standard in 3 of 8 essential amino acid categories. Yari and muricin giginya contained moderate levels of good quality protein. Only diyan kwakwa contained calorically significant amount of total fatty acid (24.7%); however, none of the plants contained useful amounts of the essential fatty acids, linoleic acid, or alpha-linolenic acid. All four plants contained useful amounts of zinc (> 12 microg/g dry weight), while yari contained the most calcium (14.7 mg/g dry weight) and iron (1.41 mg/g), and diyan kwakwa the most copper. All the four plant foods contained lesser amounts of magnesium, molybdenum, or selenium. These data indicate that the four plants contain useful amounts of various essential nutrients that could supplement the diets of populations inhabiting the Western Sahel.

Effect of Norplant contraceptive on the bones of Nigerian women as assessed by quantitative ultrasound and serum markers of bone turnover

Levonorgestrel is a commonly used progestin-only contraceptive that is available as subdermal (Norplant) and intrauterine implants. Other progestin-only contraceptives such as injectable medroxyprogeterone acetate have been shown to decrease bone mineral density in long-term users. We used calcaneal ultrasound to compare the bone quality of Nigerian women between 25 and 50 years of age who had Norplant implants for 1-4 years to that of women who were not using any form of hormonal contraceptive. The mean stiffness index of women who had Norplant implants for as long as 4 years was not significantly different from that of controls. However, serum markers of bone turnover were significantly decreased in women with Norplant implants compared to age-matched controls. Serum bone-specific alkaline phosphatase was significantly decreased in subjects with Norplant implants for 1 year (13.7+/-6.0 vs. 23.0 U/L for controls, p = .001) and serum NTx was significantly decreased in subjects with implants for 3 years (10.6+/-4.9 vs. 17.6+/-7.7 bone collagen equivalents per liter for controls, p < .001). We conclude that although levonorgestrel contraceptive decreased overall bone turnover, it had no deleterious effect on the bone quality of women using Norplant implants for up to 4 years.

Serum potassium and acid-base parameters in severe dialysis-associated hyperglycemia treated with insulin therapy

We analyzed the changes in serum potassium concentration ([K]) and acid-base parameters in 43 episodes of dialysis-associated hyperglycemia (serum glucose level > 33.3 mmol/L), 22 of which were characterized as diabetic ketoacidosis (DKA) and the remaining 21 as nonketotic hyperglycemia (NKH). All episodes were treated with insulin therapy only. Age, gender, initial and final serum values of glucose, sodium, chloride, tonicity and osmolality did not differ between DKA and NKH. At presentation, serum values of [K] (DKA 6.2 +/- 1.3 mmol/L; NKH 5.2 +/- 1.5 mmol/L) and anion gap [AG] (DKA 27.2 +/- 6.4 mEq/L; NKH 15.4 +/- 3.5 mEq/L) were higher in DKA, whereas serum total carbon dioxide content [TCO2 ] (DKA 12.0 +/- 4.6 mmol/L; NKH 22.5 +/- 3.1 mmol/L), arterial blood pH (DKA 7.15 +/- 0.09; NKH 7.43 +/- 0.07) and arterial blood PaCO2 (DKA 26.2 +/- 12.3 mm Hg; NKH 34.5 +/- 6.7 mm Hg) were higher in NKH. At the end of insulin treatment, serum values of [K] (DKA 4.0 +/- 0.7 mmol/L, NKH 4.0 +/- 0.5 mmol/L), [AG] (DKA 16.3 +/- 5.4 mEq/L, NKH 14.9 +/- 3.0 mEq/L), [TCO2 ] (DKA 23.5 +/- 5.0 mmol/L, NKH 24.1 +/- 4.2 mmol/L), arterial blood pH (DKA 7.42 +/- 0.09, NKH 7.51 +/- 0.14) and arterial blood PaCO2 (DKA 31.8 +/- 6.7 mm Hg, NKH 34.2 +/- 8.3 mm Hg) did not differ between the two groups. Linear regression of the decrease in serum [K] value during treatment, (Delta[K]), on the presenting serum [K] concentration,([K]2 ), was: DKA, Delta[K] = 2.78 - 0.81 x [K]2 , r = -0.85, p < 0.001; NKH, Delta[K] = 2.44 - 0.71 x [K]2 , r = -0.90, p < 0.001. The slopes of the regressions were not significantly different. Stepwise logistic regression including both DKA and NKH cases identified the presenting serum [K] level and the change in serum [TCO2 ] value during treatment as the predictors of Delta[K] (R2 = 0.81). Hyperkalemia is a feature of severe hyperglycemia (DKA or NKH) occurring in patients on dialysis. Insulin administration brings about correction of DKA and return of serum [K] concentration to the normal range in the majority of the hyperglycemic episodes without the need for other measures. The initial serum [K] value and the change in serum [TCO2 ] level during treatment influence the decrease in serum [K] value during treatment of dialysis-associated hyperglycemia with insulin.

Characteristics of end stage renal disease diabetic patients in two countries with different socioeconomic conditions

PURPOSE

To identify differences that may affect morbidity and mortality of type 2 diabetic patients reaching ESRD between countries with different socioeconomic conditions.

METHODS

Comparison of clinical and laboratory features between 21 Nigerian (N) and 57 American patients (A) reaching ESRD over a 30 month period.

RESULTS

Differences were noted in age at ESRD (N, 55.5+/-9.8; A, 64.5+/-9.6 years), duration of diabetes (N, 5.2+/-2.8, A: 14.9+/-4.9 years), body mass index (N, 24.5+/-4.1; A; 27.6+/-6.3 kg/m2), prevalence of left ventricular hypertrophy (N; 14%; A, 89%) and ischemic heart disease (N, 26%; A, 67%), blood pressure (N, [166.2+/-26.7]/[98.6+/-16.5] mmHg; A, [146.8+/-23.6]/[72.5+/-13.3] mmHg), creatinine clearance (N, 6.1+/-3.6; A, 14.8+/-3.5 ml/min), urine protein excretion (N, 1.2+/-0.7; A, 6.1+/-4.9 g/24-h), hematocrit (N, 28.0+/-6.0; A, 35.0+/-5.0%), serum glucose (N, 5.6+/-1.6; A, 10.5+/-5.5 mmol/l), and serum cholesterol (N, 5.32+/-2.57; A, 4.19+/-1.16 mmol/l) (all at P < or = 0.05). Differences were also found in the number of antihypertensive medications (N 1.4+/-0.6; A 2.4+/-1.2 per patient), and use of medications for diabetes (N 29%, A 79%), statins (N zero, A 61 %) and erythropoietin (N zero, A 39%). 72% of the A, but none of the N patients had a functional dialysis access prior to ESRD.

CONCLUSIONS

Between A and N patients reaching ESRD, there are differences in clinical features and laboratory values that may affect morbidity, mortality and impact on the health care resources. These differences indicate areas where further studies that could assist in the planning for ESRD care in both Nigeria and USA are required.

Lack of precision of indirect estimates of body water affects urea kinetic analysis in chronic peritoneal dialysis

To test the precision of estimates of body water and urea clearance in peritoneal dialysis (PD), we compared, in 925 PD patients who underwent formal urea kinetics studies, estimates of V and Kt/V urea obtained by the use of the Watson, Hume, and Sahlgrenska anthropometric formulas and two novel formulas, one (Vcreat) computed using fat-free mass (FFM) estimated from creatinine kinetics as 0.73 x FFMcreat, and the other (VBMI) calculated as 0.73 x FFM(BMI) where FFM(BMI) was obtained by the Gallagher formula, which estimates body composition as a function of body mass index (BMI). Comparisons by twos were performed using the paired t-test and the Wilcoxon sign rank test with the Bonferroni correction for multiple (n=10) comparisons. The results for V (liters) were Watson, 36.7 +/- 7.1; Hume, 37.3 +/- 7.3; Sahlgrenska, 36.8 +/- 7.6; Vcreat, 32.2 +/- 9.8; and VBMP 37.2 +/- 7.8. With the exception of V(BMI) and V(Hume) which did not differ, all other values differed (p < 0.001) from one another regardless of whether a parametric or nonparametric comparison was performed. The results for weekly total Kt/V urea were Watson, 2.05 +/- 0.57; Hume, 2.03 +/- 0.57; Sahlgrenska, 2.06 +/- 0.59; from Vcreat 2.42 +/- 0.71; and from V(BMP) 2.03 +/- 0.58. All of those values differed from one another (p < 0.001) by both methods of comparison. Using cut-off values (1.50, 1.75, and 2.00) as indices of adequate total weekly Kt/V urea, the discrepancies between any two estimates by the five studied formulas varied in the range 1.1% - 34.2%. Despite numerically close mean values, estimates of V based on various anthropometric formulas differ substantially and cause substantial discrepancies in the classification of Kt/V urea as inadequate or adequate. This lack of precision, added to the known lack of accuracy of the estimates, confounds the interpretation of the clinical relevance of urea kinetic estimates in PD.

Serum lipid profiles and homocysteine levels in adults with stroke or myocardial infarction in the town of Gombe in northern Nigeria

While the incidence of infectious diseases has been on the decline in developing countries, the toll of cardiovascular diseases, including stroke and myocardial infarction, has been increasing. The impression of physicians in certain regions of the western Sahel, including the state of Gombe in northeastern Nigeria, is that macrovascular disease in the indigenous population is on the rise. This study was, therefore, undertaken to compare well-established risk factors for cardiovascular disease in a group of 53 men (n=34) and women (n=19) in the town of Gombe who had suffered a stroke or heart attack with the corresponding parameters in 48 age- and gender-matched healthy adults living in the same environment. The parameters of cardiovascular diseases considered were: overweight and obesity, blood pressure, lipid profiles, and homocysteine. While the male and female patients who had suffered stroke (n=48) or heart attack (n=5) were borderline hypertensive, their mean body mass index values were not different from the corresponding values of their control groups. Although the serum homocysteine levels of the patients and controls were not significantly different, 85% of the stroke patients had serum homocysteine levels greater than 10 microM. These high homocysteine levels could not be accounted for by sub-optimal folate or vitamin B 12 status. The serum levels of HDL-cholesterol and triglyceride were not significantly different between the male and female patients and their respective controls. However, the males, but not the females, with macrovascular disease had significantly higher levels of total cholesterol (161 vs 137 mg/dL, p=0.04) and LDL-cholesterol (91 vs 70 mg/dL, p=0.02). In addition, both female and male stroke/myocardial infarction patients exhibited an elevated LDL-cholesterol/HDL-cholesterol ratio. These results indicate that blood pressure and the LDL-cholesterol/HDL-cholesterol ratio are associated with stroke and myocardial infarction in adults in northern Nigeria, thereby creating potential opportunities for possible public-health interventions.

Risk factors for cardiovascular disease and diet of urban and rural dwellers in northern Nigeria

Over the last 30 years, cardiovascular diseases (CVDs), including stroke and myocardial infarction, have increased in developing countries. Serum lipids and diet of the Fulani, a rural Nigerian population, were previously studied. Despite their consumption of a diet rich in saturated fat, the overall blood lipid profiles of Fulani men and women are generally favourable. However, Fulani males in the same study had mean serum levels of homocysteine, an emerging risk factor for CVD, that exceeded the upper limit of the homocysteine reference range. The authors were interested in knowing if these findings in the Fulani nomads were representative of the biochemical parameters of CVD risk in other ethnic groups in the same region of Nigeria. To address this question, the nutrient content of diets of 55 men, aged 20-75 years, and 77 women, aged 20-70 years, who were inhabitants of a large urban centre in northern Nigeria, was assessed, and their serum levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and homocysteine were determined. These data were compared with those of the same rural Fulani population studied previously. Urban subjects consumed more calories than rural subjects (men: 2061 vs 1691 kcal; women: 1833 vs 1505 kcal) and had a significantly higher mean body mass index (BMI) and percentage of body fat than rural subjects. Both urban males and females had carbohydrate intakes that were greater than those of Fulani pastoralists (men: 56% vs 33% total calories; women: 51% vs 38% total calories), but had a significantly lower dietary intake of total fat and saturated fat (men: 36% vs 51% of total calories; women: 40% vs 51% of total calories). With the exception of HDL-cholesterol levels, which were significantly lower in the rural population, the blood lipid profiles of rural subjects were more favourable compared to those of urban subjects. Both urban and rural males had homocysteine levels above the upper limit of the reference range for healthy adults (urban males--12.7 micromol/L; rural males-15.2 micromol/L). The dietary intakes of folate and vitamin B12 were lower for rural Fulani subjects, and this was reflected in their significantly lower serum concentrations of these two vitamins. Results of this study suggest that, although the lipid profiles of urban and rural men and women in northern Nigeria indicate a relatively low risk for CVD, their elevated serum homocysteine levels are a cause for concern. The high homocysteine levels among rural men and women could be explained in part at least by their marginal status with respect to folate and vitamin B12.

High-density lipoprotein and homocysteine levels correlate inversely in preeclamptic women in northern Nigeria

BACKGROUND

Preeclampsia/eclampsia is one of the most common complications of pregnancy. It is a cause of high morbidity for both mother and fetus, especially in developing countries. In a recent survey conducted in Gombe, Nigeria, eclampsia was found to be a major cause of maternal mortality (24.2%), second only to obstetric hemorrhage (27.1%). Previous studies have produced contradictory findings regarding total homocysteine (tHcy) levels in women with preeclampsia/eclampsia and there is little information about the relationship between particular serum lipids and tHcy. The objective of this study in Gombe was to compare the levels of serum lipids and homocysteine in healthy pregnant women and women with preeclampsia/eclampsia in Nigeria.

METHODS

The experimental subjects included 43 women with preeclampsia/eclampsia and 130 healthy pregnant women served as controls. The criteria for preeclampsia/eclampsia included the following: hypertension (blood pressure > 140/90 mmHg), total protein (> 190 mg/g creatinine), and edema. Blood sera obtained from patients and controls attending the prenatal clinics at the Specialist Hospital and the Federal Medical Center in Gombe were analyzed for tHcy, total cholesterol, triglycerides, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, antioxidant capacity, folate, and vitamin B-12.

RESULTS

The mean tHcy concentration for the preeclamptic/eclamptic women was greater than that of the controls (10.1 vs. 8.4 micromol/l, respectively, p = 0.01). The mean concentrations of LDL-cholesterol and triacylglycerols were not different between the two groups. However, the mean HDL-cholesterol level was higher in the healthy pregnant women compared with the preeclamptic/eclamptic women (1.64 vs. 1.42 mmol/l, respectively, p = 0.02). The HDL-cholesterol concentration was correlated inversely with the tHcy concentration (p = 0.001, r = 0.51). Total homocysteine was not linked with either serum folate or vitamin B-12.

CONCLUSIONS

These results show that preeclampsia/eclampsia is associated with increased tHcy levels and that HDL levels are depressed in Nigerian women with this hypertensive, pregnancy associated disorder.

Chronic hemodialysis in a Nigerian teaching hospital: practice and costs

The incidence of end-stage renal disease (ESRD) is on the rise in developing countries. To identify issues related to renal replacement therapy in ESRD patients in the developing world, we analyzed the practice and costs of hemodialysis in Nigerian ESRD patients. Ten ESRD patients were dialyzed at the Jos University Teaching Hospital, Jos, Plateau State, Nigeria, between June 15 and July 15, 2003. In these patients, we analyzed initiation, vascular access issues, frequency, duration, adequacy and economics of chronic hemodialysis. The Nigerian patients were referred to the nephrologist for the first time only when they had developed frank uremia. No patient had a permanent vascular access at the time dialysis was initiated. Only two patients had a functioning dialysis fistula, while the other eight patients were dialyzed through temporary femoral vein catheters that were removed after each dialysis. Frequency of dialysis was three times weekly in 2 patients, twice weekly in 1 patient and once weekly or less frequently in 7 patients. The duration of a dialysis session was prescribed to be 4 hours, but sessions often lasted for as long as 10 hours because of breakdowns of the antiquated dialysis machines. The urea reduction ratio was 45.3 +/- 8.6%. In every case, the cost of dialysis was borne by the patients and their families. Comparison of the cost of dialysis, with extensive re-use of supplies, to monthly incomes of Nigerians with different professions revealed that the great majority of Nigerians cannot afford three times weekly dialysis. Underdialysis in Nigerian ESRD patients is common and caused by socioeconomic factors and technologic deficits. One step towards correction of underdialysis could be sharing of the cost of dialysis by the public.

Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas

BACKGROUND

Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%).

METHODS

We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas.

RESULTS

Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess.

CONCLUSION

Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).

Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas

BACKGROUND

Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%).

METHODS

We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas.

RESULTS

Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess.

CONCLUSION

Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).

Weight status classification of patients on continuous peritoneal dialysis

We tested the agreement between classifications of the weight status of patients on peritoneal dialysis (PD) by body mass index (BMI) and by body fat (BF) content (BF/W, where W = actual weight), when BF was computed as BF = W - V/0.73 from the Sahlgrenska, Watson, or Hume anthropometric formulas estimating body water (V) in 933 patients on PD and 7,737 outpatients without hydration disorders. We used currently accepted cut-off values for classifying subjects as underweight, normal-weight, overweight, and obese by BMI and BF/W. We obtained these values: BMI: men on PD (n = 555), 25.5 +/- 4.3; men with normal renal function [NRF (n = 5,906)], 27.7 +/- 5.1; women on PD (n = 378), 25.9 +/- 6.1; women with NRF (n = 1,831), 28.3 +/- 6.5; BFSahlgrenska/W--men on PD, 0.238 +/- 0.063; men with NRF, 0.274 +/- 0.052; women on PD, 0.342 +/- 0.89; women with NRF, 0.366 +/- 0.075. We obtained these regressions: Women on PD BMI = 12.0832 + 38.9550 (BFSahlgrenska/W) -92.9252 (BFSahlgrenska/W)2 +254.0675 (BFSahlgrenska/W)3, r2 = 0.917; Men on PD BMI = 19.4729 - 29.1310 (BFSahlgrenska/W) +213.7045 (BFSahlgrenska/W)2, r2 = 0.888. From those regressions, the BMI value corresponding to the BFSahlgrenska/W cut-off for underweight was similar to the National Institutes of Health (NIH) BMI cut-off for underweight. The BMI value corresponding to the BFSahlgrenska/W cut-off for obesity was substantially lower than the NIH BMI cut-off for obesity. The kappa ratios of the classifications of weight status by BMI and BFSahlgrenska/W varied between 0.142 and 0.304 (poor agreement), with more than 50% of the subjects classified in a more obese weight category by BFSahlgrenska/W than by BMI. Classification of the subjects by BMI and by BFSahlgrenska/W in quintiles or quartiles led to much higher kappa ratios, particularly in women. The results were similar in subjects with NRF and with the use of the Watson and Hume formulas to estimate BF. The use of arbitrary cut-off values of BMI or anthropometric BF/W to classify PD patients or patients without edematous states as underweight, normal-weight, overweight, or obese leads to substantial disagreement between the two classifications. Classification of weight status by BMI or BF/W in quintiles or quartiles improves substantially the agreement between the two classifications and should be preferred.

Body composition evaluation in peritoneal dialysis patients using anthropometric formulas estimating body water

In adult patients on peritoneal dialysis (PD), estimates of body water (V), fat-free mass (FFM), and body fat (BF) can be obtained by using anthropometric formulas for estimating V. Estimates of V, FFM, and BF can also be obtained by using reference (standard) methods in which V is evaluated by a standard dilution method. To test whether the estimates obtained by the various methods agree, we analyzed published studies that measured V by a standard method in adult PD patients. We then calculated V, FFM, and BF by the Watson, Hume, Sahlgrenska, Chumlea, Lee, and Chertow formulas for the "average subject" in the published studies. We compared the standard and the anthropometric estimates using the limits-of-agreement method of Bland and Altman. Our analysis included six studies involving a total of 262 patients (89 women, 173 men). The six studies measured V by a reference method and allowed calculation of anthropometric V, FFM, and BF for the average patient. We calculated these values: VStandard, 36.8 +/- 4.7 L; VSahlgrenska, 36.9 +/- 4.3 L [p = nonsignificant (NS); Bland-Altman limits of agreement: -3.1 L to 3.3 L]; FFMStandard 50.9 +/- 5.2 kg; FFMSahlgrenska, 50.6 +/- 4.3 kg (Bland-Altman limits of agreement: -5.4 kg to 4.8 kg); BFStandard, 20.3 +/- 3.0 kg; BFSahlgrenska, 20.6 +/- 2.3 kg (Bland-Altman limits of agreement: -4.8 kg to 5.4 kg). Results obtained using the Watson, Hume, Chumlea, and Lee formulas also agreed with the standard estimates. The Chertow formula produced results that systematically overestimated the standard V and FFM values and that underestimated the standard BF. The Watson, Hume, Sahlgrenska, Chumlea, and Lee anthropometric formulas used to calculate V provide estimates of body composition that approximate those obtained using standard methods in PD patients with average body composition. Anthropometric estimates may cause large systematic errors in PD patients whose body composition varies from the average, particularly obese or overhydrated patients.

Normalization of protein nitrogen appearance by various size indicators in patients on continuous peritoneal dialysis

Protein nitrogen appearance (PNA) estimated from urea nitrogen appearance (UNA) reflects dietary protein intake and is an important index of nutrition in peritoneal dialysis (PD). Normalization of PNA by several body size indicators has resulted in discrepancies between normalized PNA (nPNA) values and other nutrition indices in PD patients with varying weight status. To test whether a particular size indicator produces nPNA values that eliminate the discrepancies, we normalized PNA values obtained at the first clearance study in 925 PD patients by weight (W), by fat-free mass (FFM) obtained from body water, by lean body mass (LBM) derived from creatinine kinetics, by desirable weight (DW), by standard weight (SW), and by adjusted edema-fee body weight (aBW). We classified patients into three groups according to W/DW: an underweight group [group I: W/DW < 0.9, n = 147 (15.9%)], a normal-weight group [group II: 0.9 < or = W/DW < 1.2, n = 506 (54.7%)], and an obese group [group III: W/DW > or = 1.2, n = 272 (29.4%)]. The UNA and PNA increased progressively from group I to group III. The W, FFM, LBM, SW, and aBW also increased progressively, and the corresponding nPNA values decreased progressively from group I to group III--all at p < 0.001. The DW did not differ significantly between the three groups. The PNA values normalized by DW were 0.91 +/- 0.21 (group I), 0.96 +/- 0.24 (group II), and 1.07 +/- 0.25 (group III), p < 0.001. Of the six size indicators tested, only DW produced values of nPNA consistent with the nutrition status of PD patients with varying weight status. Our findings indicate that DW is the proper size indicator for normalizing PNA in PD patients.

Fatty acid, amino acid, and trace mineral analyses of five weaning foods from Jos, Nigeria

Five plant-based weaning foods (WF) (Dietrend, Jot-M, Soy, Ang, and Vic-T) locally prepared in Jos, Nigeria were analyzed by gas-liquid chromatography, reverse-phase high performance liquid chromatography, and atomic emission spectrometry with inductively coupled plasma to determine their fatty acid (FA), amino acid, and trace mineral contents, respectively. Results of these direct analyses were compared to expected values derived from food composition tables prepared by the United States Department of Agriculture (USDA). Additionally, results were compared against recommended nutrient values, using breast milk as the standard for FA content and recommended dietary allowances (RDA) for amino acid and mineral contents. The overall nutritional value of the five WF varied considerably and the quantities of particular nutrients determined by direct analysis differed markedly from those estimated using USDA food tables. Comparison of WF fatty acid composition relative to the RDA recommendations and a human milk standard revealed a much higher proportion of both linoleic (35-55 wt%) and alpha-linolenic acids (1%-7 wt%) relative to human milk lipids (11%-12% and 0.8%-0.9% wt, respectively); however, the WF were devoid of arachidonic acid and docosahexaenoic acid. Soy contained the highest amounts of linoleic acid (59.7 mg/g) and alpha-linolenic acid (7.46 mg/g) compared to the other four WF (10.2-41.0 and 0.35-3.18 mg/g, respectively). The linoleic acid/alpha-linolenic acid ratio was within the recommended range (5:1 to 10:1) in only Jot-M (10:1) and Soy (8:1). Dietrend, Vic-T and Ang, contained linoleic/alpha-linolenic ratios of 12:1, 29:1, and 82:1, respectively. The Soy weaning food would provide the most protein (24.3 g/day), based on an estimated daily intake of 65 g of weaning food by a normal six-month-old infant, compared to Jot-M (11.9 g/day), Dietrend (11.7 g/day), Ang (8.07 g/day), and Vic-T (7.26 g/day). The protein RDA for children up to 1 year of age is 13-14 g/day. Comparison of the mineral contents of the WF to the RDAs for various minerals indicated that all five would provide suboptimal amounts of calcium (16 to 250 mg/day) and zinc (1.42 to 3.56 mg/day) compared to respective RDAs of 400 mg/day and 5 mg/day. These data show that the Soy weaning food is an excellent source of linoleic acid and alpha-linolenic acid, as well as being a good source of high quality protein. Jot-M and Dietrend provide useful amounts of the essential FA; however, it is advisable to reevaluate the composition of Ang and Vic-T to find ways to improve the linoleic/alpha-linolenic ratio of each and increase their total protein content. These results document the shortcomings of using published food composition tables based on foods in America when devising weaning foods based on ingredients in another part of the world.

Assessment of the bone status of Nigerian women by ultrasound and biochemical markers

Ultrasound analysis of the calcaneus and serum markers of bone turnover were used to examine the bone status of healthy Nigerian women who reside in an area of the world where dietary calcium intake is generally low and estrogen replacement therapy is not widely available. A total of 218 women (108 premenopausal and 110 postmenopausal) between the ages of 16 and 95 years were enrolled in the study. Broadband ultrasound attenuation (BUA) and speed of sound velocity (SOS) were measured and used to calculate the stiffness index (SI) of the calcaneus. In this cross-sectional study, the Nigerian women exhibited a marked age-dependent decline in SI that was defined by the regression equation SI = 105.9 - 6.62E-3 x Age2. SI was significantly correlated with age (r = -0.41, P < 0.001) and with serum NTx concentrations (r = -0.26, P < 0.001), but not with serum levels of bone-specific alkaline phosphatase (BSAP). Years since menopause was also significantly correlated with SI (r = 0.40, P < 0.001). A significant increase in serum NTx concentration occurred at least a decade before a significant decline in SI was evident. In the total study group, 24% of the women had T-scores indicative of osteopenia and 9% had T-scores indicative of osteoporosis, based on US reference data. Although the reported current incidence of fracture is low in women in sub-Saharan West Africa, these data show that after menopause Nigerian women have a decline in bone quality and increase in bone turnover similar to North American Caucasian women.

The trypsin inhibitor content of 61 wild edible plant foods of Niger

In the western Sahel and many other regions of sub-Saharan Africa, wild edible plants contribute significantly to human diets, not only during periods when cereal staples are scarce, but also when they are readily available. Although there have been published reports regarding the nutrient contents of these plant foods, little attention has been devoted to their content of antinutrients such as calcium chelators and inhibitors of the pancreas-derived proteases, trypsin and chymotrypsin, which are required for the efficient digestion and absorption of dietary proteins. In this study, aqueous extracts of 61 different leaves, seeds, fruits and flowers of edible plants gathered in the Republic of Niger were analyzed for their content of trypsin inhibitory substances using alpha-N-benzoyl-DL-arginine-p-nitroanilide as the substrate and bovine trypsin as the enzyme source. Twelve of these plant foods contained more antitrypsin activity than soybeans (1.34-8.18 vs. 1.32 microg trypsin inhibited/mg dry weight). Boiling for 3 min did not inactivate the antitrypsin activity in most of the plant extracts. These data confirm that more than half of the wild edible plant foods widely consumed by various populations who inhabit the western Sahel contain significant quantities of heat-stable trypsin inhibitor that could possibly compromise the bioavailability of proteins present in the diets of these populations.

Calcium supplements increase the serum levels of crosslinked N-telopeptides of bone collagen and parathyroid hormone in rachitic Nigerian children

OBJECTIVES

Biochemical markers of bone turnover were measured in the sera of 16 controls and 10 children with calcium-deficiency rickets, during a 12-week course of calcium supplementation (1 g CaCO3/d) that was effective in healing the bone lesions of the rachitic children.

DESIGN AND METHODS

Serum levels of crosslinked N-telopeptides of bone collagen (NTx), parathyroid hormone (PTH), alkaline phosphatase (ALP), and urinary deoxypyridinoline (LP) were assayed at baseline and during the course of calcium therapy and compared with data of the 16 non-rachitic controls.

RESULTS

Calcium therapy suppressed serum NTx and PTH levels in the rachitic children within 24 h; however, after the first week, PTH and NTx levels increased to the extent that at 12 weeks both were elevated when compared with controls or to baseline levels. Serum levels of NTx and PTH were correlated in the controls and experimental subjects (r = 0.63, p < 0.001).

CONCLUSIONS

The rate of bone resorption, as estimated by serum NTx concentration, is increased during the healing of rachitic lesions.

Nutrient content of the edible leaves of seven wild plants from Niger

Wild plants play an important role in the diet of the inhabitants of Niger. These plants tend to be drought-resistant and are gathered both in times of plenty as well as times of need. Used in everyday cooking, famine foods may be an important source of nutrients. The goal of this study was to investigate the nutritional role of wild plants in the nigérien diet. To this end, leaves of seven plants species were analyzed for their mineral, amino acid and fatty acid contents: Ximenia americana, Amaranthus viridus, Corchorus tridens, Hibiscus sabdarifa, Maerua crassifolia, Moringa oleifera, and Leptadenia hastata. Ximenia americana contained large amounts of calcium. Large quantities of iron were present in Amaranthus viridus. All seven plants contained significant amounts of selenium and phosphorus. Corchorus tridens contained the most protein (19-25% dry weight), and its composition compared favorably to the World Health Organization's standard for essential amino acids. Moringa oleifera contained 17% protein and compared favorably with the WHO standard. Corchorus tridens contained the largest amounts of the two essential fatty acids linoleic and alpha-linolenic acids. These results reinforce the growing awareness that wild edible plants of the Western Sahel can contribute useful amounts of essential nutrients, including amino acids, fatty acids and trace minerals, to human diets.

Analysis of nutritional components of eight famine foods of the Republic of Niger

In the western Sahel, indigenous plants become important staples when cereal harvests are inadequate to support populations inhabiting that region of Africa. The purpose of this study was to assess the nutrient content of several of these edible wild plants. The leaves of the following seven plant foods were analyzed: Ziziphus mauritiana, Cerathotheca sesamoides, Moringa oleifera, Leptadenia hastata, Hibiscus sabdarifa, Amaranthus viridis, and Adansonia digitata. The fatty acid, vitamin E, carotenoid, selected mineral and amino acid contents of these plant foods were determined. These same analyses were performed on the fruit of the Adanisonia digitata. In quantitative and qualitative terms, Amaranthus viridis was found to be an excellent source of protein. Its amino acid composition compared favorably to that of a World Health Organization (WHO) protein standard. It also contained considerable amounts of the two fatty acids that are essential in humans (linoleic and alpha-linolenic) and a number of minerals including iron, magnesium. calcium and zinc. The leaves of Hibiscus sabdarifa contained an appreciable quantity of protein the composition of which was comparable to the WHO standard. The mineral content of the leaves of this plant was also exceptionally high; noteworthy was its high zinc content. H. sabdarifa also contained significant quantities of the two essential fatty acids. Ziziphus mauritiana was an excellent source of the essential fatty acid linoleic acid and several of the metals including iron, calcium, magnesium and zinc. Its content of other essential nutrients, however, was rather low. In general, Adansonia digitata leaves were nutritionally superior to the fruit of the tree; however, the fruit did contain useful quantities of potassium, phosphorus, zinc and alpha-linolenic acid. The Leptadenia hastata leaves were an especially good source of lutein and beta-carotene. These data should be useful to the people who inhabit the western Sahel in helping them devise healthy diets during times when cereal staples are in short supply.

Human glucocerebrosidase catalyses transglucosylation between glucocerebroside and retinol

The basal activity of human placental glucocerebrosidase is elevated 16-fold by n-pentanol when assayed using p-nitrophenyl beta-D-glucopyranoside (pNPGlc) as the beta-glucosidase substrate. This enhancement of activity is the result of the formation of a transglucosylation product, n-pentyl beta-D-glucoside, in rate-determining competition with the hydrolytic reaction. The transglucosylation product accounts for approximately 80% of the reaction product generated in the presence of n-pentanol (0.18 M) when either glucocerebroside or pNPGlc was used as the substrate. This stimulatory effect can be increased an additional 3-fold by the inclusion of phosphatidylserine (20 micrograms/ml) or sodium taurodeoxycholate (0.3%, w/v) in the incubation medium. In the presence of retinol, glucocerebrosidase also catalyses the synthesis of a novel lipid glucoside, retinyl glucoside, when either glucocerebroside or pNPGlc serves as the substrate. The reaction product was identified as retinyl beta-D-glucoside, based on its susceptibility to hydrolysis by almond beta-D-glucosidase and the subsequent release of equimolar amounts of retinol and glucose. The rate of retinyl-beta-glucoside formation is dependent on the concentration of retinol in the incubation medium, reaching saturation at approximately 0.3 mM retinol. Retinyl beta-D-glucoside is a substrate for two broad-specificity mammalian beta-glucosidases, namely the cytosolic and membrane-associated beta-glucosidases of guinea pig liver. However, retinyl beta-D-glucoside is not hydrolysed by placental glucocerebrosidase. These data indicate that the glucocerebrosidase-catalysed transfer of glucose from glucocerebroside to natural endogenous lipid alcohols, followed by the action of a broad-specificity beta-glucosidase on the transglucosylation product, could provide mammals with an alternative pathway for the breakdown of glucocerebroside to glucose and ceramide.

Ascorbic acid intakes and plasma levels in healthy elderly

The data presented show that elderly men have significantly lower plasma ascorbic acid concentrations than elderly women at similar intakes of ascorbic acid. We hypothesize that this difference is due to lower renal tubular reabsorption of ascorbic acid in elderly men. The finding that more than half of the healthy elderly men had plasma ascorbic acid levels less than 0.3 mg/dl with daily intakes of ascorbic acid in the range of 40 to 50 mg raises concern about the rationale of lowering the RDA for vitamin C from the current value of 60 mg to 40 mg for men and 30 mg for women. This recommendation is inconsistent with efforts to improve the health status of elderly Americans by assuring adequate intakes of all essential nutrients. Our data do not allow us to determine an optimal intake of ascorbic acid for the elderly. The possibility of increased health benefits associated with intakes that exceed the current RDA of 60 mg needs to be examined. We believe, however, that a prudent approach to both of these questions would be to recommend that elderly receive a daily ascorbic acid intake that would allow plasma concentration to be maintained at or near 1.0 mg/dl. The daily level of intake required to maintain this level would be approximately 125 mg and 75 mg in healthy elderly men and women respectively. These intakes would assure adequate body reserves of ascorbic acid.