Age dependency of the lactase persistence and lactase restriction phenotypes among children in Sri Lanka and Britain.

All neonates are born with intestinal lactase activity. In most of them the intestinal lactase activity is lost during childhood (lactase restriction phenotype). In a minority of children normal intestinal lactase activity is retained (lactase persistence phenotype). In this study the progression of the lactase restriction phenotypes has been studied in 94 Sri Lankan children by oral lactose loads and 162 British children by intestinal lactase estimation (adult Sri Lankans and British predominantly belong to the lactase restriction and lactase persistence phenotypes, respectively). Lactase was present in infancy at birth in all Sri Lankan children and declined around the age of eight years, the majority (59 per cent) of the 10-15-year-olds belonging to the lactase restriction phenotype. In contrast the majority of the British children (95 per cent of all the British children studied) demonstrated the lactase persistence phenotype. The low prevalence rate of the restriction phenotype found among British children was largely contributed by children of African and Asian origin.

Characteristics of blood gas in response to iron treatment and exercise in iron-deficient and anemic subjects.

The effects of iron deficiency anemia and iron treatment on blood gas and acid-base balance at rest and during exercise were studied. Eight Sri Lankan males and 13 females were randomly divided into an iron treatment or placebo group. Their initial hemoglobin (Hb) levels were 6.2 +/- 0.5 and 5.5 +/- 0.7 g/100 ml (mean +/- SEM) with serum iron levels of 41 +/- 8 and 30 +/- 6 micrograms/100 ml, respectively. Hemoglobin concentration was increased significantly within 7 days after iron treatment to 7.2 +/- 0.4 g/100 ml. Resting lactate was higher than normal, while base excess, buffer base, and actual bicarbonate were lower, maintaining a normal pH. Heart rates during exercise at a given work load and lactate production following exercise decreased after the elevation of Hb. Venous blood PCO2 rose as Hb concentration increased, preceding a significant increase in resting O2 content, 16 days after iron treatment. With anemia, O2 delivery is potentially maintained by a shift of the O2-dissociation curve to the right due, in part, to 2,3-diphosphoglycerate. There was no significant change in PO2 or Hb-O2% saturation following exercise or iron treatment. These data suggest that severe iron deficiency anemia results in lactate accumulation in blood even at rest but pH is maintained within normal limits. It was also suggested that severe anemia may impair CO2 transport capacity of blood which could limit continuation of muscle metabolism.

Elevation of hemoglobin and work tolerance in iron-deficient subjects.

Selected parameters related to work tolerance were measured in 31 adult subjects with hemoglobin (Hb) concentration from 2.5 to 14.0 g/100 ml. Work tolerance was closely related to Hb concentration (r = 0.74) regardless of the adequacy of storage iron level. One male and six females with a mean Hb of 3.5 g/ml (27-55 years old) were studied before and 24h after transfusing 570ml of whole blood. The mean maximal work load tolerated increased 83% within 24h after transfusion in these seven subjects. Post-exercise venous blood lactate was markedly lower after transfusion. Work tolerance of these subjects within 24h after transfusion was the same as in other subjects who had had the equivalent Hb level as the post-transfusion subjects presumably for at least several weeks. These data suggest that the decrement in work performance capacity in iron-deficient and anemic subjects is, in a large part, a reflection of the level of anemia rather than other non-Hb related biochemical changes that could accompany prolonged iron deficiency anemia.

Work capacity after iron treatment as a function of hemoglobin and iron deficiency.

The relative importance of hemoglobin (Hb) and non-Hb iron for physical work capacity was studied in 45 adult male and female subjects, with a range of Hb and serum iron levels. Maximal work capacity, heart rate, venous blood lactate and serum protein were measured before and after 1 week of treatment with Imferon, i.v. Even though some non-Hb related effects on parameters indicative of maximal work capacity were found, the main factor was Hb related. Subjects with low Hb-high serum iron worked longer than ones with low Hb-low iron. When work performed was similar, the marginal Hb-low iron group had a higher blood lactate concentration than the high Hb-high iron and marginal Hb-high iron groups. The coefficient of correlation between serum iron and post-exercise lactate levels was -0.41 (p less than 0.05). Even though neither of these groups showed a Hb response within 1 week of iron treatment, the initial low serum iron groups had significantly lower heart rates at a given work load relative to subjects with high iron but with a similar Hb level. This occurred both at rest and during light to heavy exercise. These results suggest that a rather rapid benefit of iron treatment is gained in iron-deficient subjects with severe and moderate anemia which cannot be accounted for by Hb changes. Although the primary factor which affects the physical work capacity of iron-deficient anemic subjects seems to be the Hb level, there also seems to be a significant non-Hb related effect of iron treatment as well.

Serum lipid levels in iron deficiency anemia and effects of various treatments.

Effects of anemia on serum total cholesterol and triglyceride levels were studied in Sri Lanka. In subjects with hemoglobin (Hb) levels of less than 9.0 g/100 ml, there was a significant relationship between Hb and cholesterol levels (r = 0.53). This relationship was not seen in subjects with Hb levels equal to, or greater than, 9.0 g/100 ml. Triglyceride levels were independent of Hb levels. Total cholesterol levels were elevated following an increase in Hb levels by transfusion and iron treatment. It was suggested that the concentration of red blood cells may affect cholesterol synthesis or mobilization from tissue to plasma.

Iron-deficiency anaemia and its effect on worker productivity and activity patterns.

The effects of iron-deficiency anaemia on workers productivity were studied in a tea plantation in Sri Lanka. The quantity of tea picked per day was studied before and after iron supplementation or placebo treatment. After one month's treatment significantly more tea was picked when the haemoglobin (Hb) concentration was increased by iron supplementation than when it was not. The degree of improvement was greater in more-anaemic subjects (those with concentrations of 6.0-9.0 g Hb/dl). The level of physical activity of anaemic subjects in their everyday environment was also recorded for four or 24 hours continuously both before and after treatment. After three weeks these levels was significantly greater in the iron-treated than matched placebo-treated subjects. The economic implications of increased work productively with iron treatment are evident, particularly in developing countries. These results also provide strong evidence for the clinical impression that people with iron-deficiency anaemia suffer from tiredness and weakness.

Work capacity, heart rate and blood lactate responses to iron treatment.

Changes in haemoglobin (Hb), work performance, heart rate and postexercise blood lactate were studied in iron deficient, anaemic subjects for 16 d following total dosage infusion of iron dextran, i.v. (30-50 ml). Six adult men and 14 women were subjects with initial Hb levels of 6.6 +/- 0.6 g/dl (mean +/- SEM) for the iron treatment group (n=10) and 8.0 +/- 0.7 for the placebo group (saline infusion, n=10). Serum levels were 0.51 +/- 0.15 and 0.67 +/- 0.12 mg/l for the two groups, respectively. Haemoglobin and maximal work time increased significantly within 4 d after iron treatment and continued to increase up to 16 d. No changes were found in the placebo subjects. Heart rates at a given exercise intensity were lower in the iron treatment group than in control subjects who had the same Hb levels but had not been treated with iron. Post-exercise venous blood lactate was similar on succeeding days after iron treatment even though the subjects reached higher work loads. These results demonstrate the treatment of iron deficient, anaemic subjects with iron dextran results in improved work capacity within 4 d and a lower heart rate at a given work load after treatment which cannot be accounted for totally by the elevation of Hb concentration.

Reassessment of the Widal test in the diagnosis of typhoid.

The Widal test was done in 100 nontyphoidal febrile pients, 53 patients with proven typhoid, and in 61 patients with immunological disturbances in an are where typhoid is endemic. Salmonella typhi H or O agglutinin titers of 1:160 or more were seen in only 1% of nontyphoidal fevers. Using these criteria, the Widal test was of diagnostic value in 50 of 53 (94.3%) of patients with typhoid. The Widal test was positive in 85.7% of patients even in the first week of the illness, possibly owing to the hyperimmune state of the patients. A false-positive test was found in 11.5% of patients with major immunological disturbances in whom the Widal test must therefore be interpreted with caution.

Intestinal lactase deficiency in Ceylon (Sri Lanka).

Lactose tolerance tests (LTT) in 200 normal adult Ceylonese have shown that 145 (72.5%) had a flat LTT, indicating a population prevalence of lactase deficiency of 66.2 to 78.8%. Jejunal lactase estimations in a smaller sample (41) confirmed this. Twelve of 55 subjects (21.8%) with a normal LTT had intestinal symptoms after lactose and intestinal lactase was low in most of them. It is suggested that little lactase is required to elevate the blood sugar but that more may be required to prevent diarrhea. On the other hand, 65.5% had no symptoms despite a flat LTT, and the possible reasons for this are considered.

A comparative study of the relative efficacy of pyrantel pamoate, bephenium hydroxynaphthoate and tetrachlorethylene in the treatment of Necator americanus infection in Ceylon.

The clearance of hookworm (Necator americanus) ova by a single dose of tetrachlorethylene (T.C.E.) was compared with that produced by single and multiple dose regimes of bephenium hydroxynaphthoate and pyrantel pamoate. Single doses of bephenium and pyrantel were inferior to T.C.E. Three daily doses of bephenium or pyrantel produced effects comparable with a single dose of T.C.E. Because of the low cost and lack of side effects, T.C.E. remains the drug of choice in the treatment of N. americanus in infections; the only disadvantage of T.C.E. is its unnoticed deterioration under tropical conditions.

A simple finger-prick method of screening for abnormal hemoglobins.

Thambipillai, Shanthi, and Senewiratne, B.: A simple finger-prick method of screening for abnormal hemoglobins; Am J Clin Pathol 63: 836-840, 1975. Two simple methods of hemoglobin electrophoresis of samples obtained by finger prick are described. The methods do not involve venipuncutre, centrifugation, or the preparation of a hemolysate, and can be carried out on starch gel or cellulose acetate membranes. The specimen can be collected even by non-medical personnel and sent by post to the laboratory. Alternatively, electrophoresis can be carried out in the field and the results obtained within 20 minutes. Both methods are suitable for population screening and pediatric studies. The method will detect structurally abnormal hemoglobins only.