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Twin girls with deletion 1p13.3----22.3 are reported. They are characterised by psychomotor retardation, short stature, narrowing of the external auditory meati and abnormalities of the digits. A high resolution analysis revealed the karyotype to be: 46,XX,-1,-4,-9,-18, +der(1)t(1:9) (p22.3;q13)inv(1)(p13.2:q25) del (1)(p13.3----22.3)t(4:18)(4qter----4q32::18q22----1 8qter; 18qter----18q22::4q32----4qter). A phenotype-karyotype correlation study of this case and three others did not support the delineation of a distinct syndrome.

We have examined the feasibility of a telemedicine-enabled screening service for children and adolescents with diabetes in Queensland. There are approximately 1400 young people with diabetes in Queensland and only about two-thirds of them are screened in accordance with international guidelines. A regional retinal screening service was established using a non-mydriatic digital retinal camera. Seven centres volunteered to participate in the study. During a five-month pilot trial, 83 of the young people with diabetes who attend these centres underwent digital retinal screening (3.7%). Retinal images were sent via email to a paediatric ophthalmologist for review and results were returned via email. A copy of each participant's results was forwarded by mail to the referring diabetes doctor and the participant and family. The majority of the image files (96%) were rated as excellent or good. Only one participant was identified as having an abnormal result. Participants and their families expressed satisfaction with the digital retinal screening process.

o|1. Vitamin B 12 deficiency induced in the fruit bat by a combination of dietary deprivation and exposure to nitrous oxide (N 2 O) is accompanied by profound neurological impairment, thus providing an experimental model for the study of vitamin B 12 neuropathy. 2. Electron microscopy of the spinal cord of vitamin B 12 deficient bats shows marked changes in the myelin of the posterior columns in the form of distension, separation and vacuolation of myelin lamellae similar to the changes described in the dietary induced B 12 deficient monkey model. 3. No equivalent change occurred in bats exposed to N 2 O and supplemented with vitamin B 12 .

The metabolism and intracellular recycling of methionine requires vitamin B12 as cofactor and methyltetrahydrofolate as coreactant. To examine the interrelationship between serum levels of methionine, vitamin B12 and folate, serum methionine levels were assayed in patients with reduced levels of these vitamins and in healthy subjects. Approximately half the patients with either vitamin B12 or folate deficiency, and more than half those with combined deficiency, had methionine levels below the reference range (37-136 mumol/l). There was no correlation between vitamin B12 or folate and serum methionine levels within the healthy group. There was also no correlation within the group with low folate levels. Within the vitamin B12 deficient group on the other hand, the correlation was highly significant (r = 0.547, p less than 0.001). The finding that many patients with vitamin B12 or folate deficiency have normal serum levels of methionine suggests a significant role for other factors such as betaine-dependent methionine synthesis in the maintenance of serum methionine concentrations.

Supplementation of the diet with valine or isoleucine protects the fruit bat from neurological impairment associated with experimentally induced vitamin B12 deficiency. Valine and isoleucine are precursors in the vitamin B12 dependent propionic acid pathway and it is proposed that they exert their protective effect through stimulation of this pathway. This suggests that the previously observed protective effect of methionine may be mediated also through this pathway, since methionine may be metabolised via the transsulfuration pathway to propionyl CoA. The results of this study refocus attention on the propionic acid pathway, and specifically on the methylmalonyl CoA mutase reaction, as central to the biochemical basis of the vitamin B12 neuropathy.

1. The effect of cobalamin inactivation by the anaesthetic gas nitrous oxide on the concentration of S-adenosylmethionine (Ado Met) in brain and liver of fruit bats (Rousettus aegyptiacus) was examined.2. Test animals exposed to N2O–oxygen (50:50, v/v) developed ataxia and paralysis leading to death after an average of 9·8 weeks (n 6). Animals receiving pteroylmonoglutamic acid supplements in the diet became ataxic earlier (mean 8·8 weeks) while those receiving methionine supplements survived for significantly longer periods (12·5 weeks, P < 0·01).3. Plasma cobalamin levels indicated severe depletion of cobalamin stores in N2O-exposed animals.4. The mean concentration of Ado Met in the brain of N2O-treated bats was nearly 50% higher than that of untreated controls. Ado Met levels in treated bats receiving pteroylmonoglutamic acid or methionine supplements were respectively 18 and 25% higher than in controls. In contrast, the concentration of Ado Met in the liver of all the N2O-treated groups was slightly lower than in controls.5. These results suggest that the N2O-induced neuropathy in the fruit bat is not related to a depletion of Ado Met in the nervous system.

Fruit bats are an animal model for the neurologic damage which occurs in vitamin B12-deficient humans. Cobalamin (vitamin B12) analogs were not detected in the plasma of fruit bats treated with nitrous oxide (N2O), which inactivates cobalamin. This observation does not lend support to the suggestion that the neurological changes associated with cobalamin inactivation by N2O and/or cobalamin deficiency per se may be related to the accumulation of cobalamin analogs. However, although the plasma of control fruit bats lacked analogs, we did find analogs in their livers, at levels about 10% of total liver corrinoids, similar to human liver analog levels.

Spinal cords were removed from ten Egyptian fruit bats Rousettus aegyptiacus and the lipids analysed. The major phosphatides were choline glycerophosphatide (32.3%), ethanolamine glycerophosphatide (29.3%), serine glycerophosphatide (15.2%) and phosphatidylinositol (8.4%). Sphingomyelin accounted for 13.8% of the phospholipid. Glycosphingolipids amounted to 43.2 mol/100 mol lipid phosphorus, plasmalogens 32.5 mol/100 mol P and cholesterol 159.5 mol/100 mol P. The fatty acid composition of whole cord, sphingomyelin and non-hydroxy cerebroside were determined. The results were compared with data from other species.

Nitrous oxide, which inactivates cobalamin when administered to fruit bats, results in severe neurological impairment leading to ataxia, paralysis and death. This occurs after about 6 weeks in animals depleted of cobalamin by dietary restriction, and after about 10 weeks in cobalamin replete bats. Supplementation of the diet with pteroylglutamic acid caused acceleration of the neurological impairment - the first unequivocal demonstration of aggravation of the neurological lesion in cobalamin deficiency by pteroylglutamic acid. The administration of formyltetrahydropteroylglutamic acid produced similar aggravation of the neurological lesion. Supplementation of the diet with methionine protected the bats from neurological impairment, but failed to prevent death. Methionine supplementation protected against the exacerbating effect of folate, preventing the development of neurological changes. These findings lend support to the hypothesis that the neurological lesion in cobalamin deficiency may be related to a deficiency in the methyl donor S-adenosylmethionine which follows diminished synthesis of methionine.

[2-14C]Tetrahydropteroylglutamic acid and 5-[G-3H]methyltetrahydropteroylglutamic acid were given intraperitoneally to fruit bats. Folate polyglutamates were formed in the liver from both substrates in different amounts and at different rates. The methylfolate pool appeared to remain separate from the tetrahydrofolate pool. More polyglutamate was formed from tetrahydropteroylglutamic acid than from 5-methyltetrahydropteroylglutamic acid. There was a fall in the folate content of the liver in the vitamin B-12-deficient bat and a more rapid incorporation of folates into polyglutamates but thereafter a more rapid loss of the labelled folate from liver.

Folate in the brain of the South African fruit bat consists of 10-formyltetrahydropteroylglutamic acid and the tri-, tetra- and penta- forms of 5-methyltetrahydropteroylglutamic acid. Following parenteral injection, only 5-[3H]-methyltetrahydropteroylglutamic acid was taken up by the brain, but none of a dose of 14C-labelled tetrahydropteroylglutamic acid was detectable. Only trace amounts of the 5-methyltetrahydropteroylglutamic acid were converted into the formyl compounds and a small amount of methyltetrahydropteroyltriglutamic acid appeared after 96 h. There was no significant difference in vitamin B-12-deficient animals.

1. 1. Fruit bats Rousettus aegyptiacus were depleted of vitamin b 12 by exposure to the gas nitrous oxide (N 2 O-oxygen, 1:1 v/v) for 57–80 days. 2. 2. Conduction velocities along the fastest fibres of the ulnar nerve, as well as the first and second peaks, were similar in control and vitamin B 12 depleted animals. 3. 3. It is concluded that neurological impairment resulting from depletion of vitamin b 12 by N 2 O does not involve significant impairment of ulnar nerve function in this species.

The weights of the brains of vitamin B12-deficient baby bats (Rousettus aegyptiacus, 4-20 day old) were slightly lower than those of B12-replete infant bats. Liver and kidney organ weights were similar in the two groups. Brain and liver B12 levels of B12-deficient baby bats were significantly lower than those of replete controls. Kidney B12 levels in deficient babies were about one quarter those of the replete babies. Brain vitamin B12 levels in B12-deficient sucklings were significantly lower than those of B12-deficient adult bats (P less than 0.01). These findings reinforce the need for adequate vitamin B12 nutrition in pregnant and lactating animals.

Thiamine and vitamin B6 status was evaluated in 73 consecutive black patients with cardiac failure at Baragwanath Hospital. They consumed moderate to large amounts of traditional as well as Western-type beer and liquor. Thirty per cent had erythrocyte thiamine concentrations below the reference range. The transketolase response to thiamine pyrophosphate (TPP effect) suggested thiamine deficiency in 32.4%, of whom 13.2% were classified as severely deficient. Vitamin B6 deficiency was present in 21.4%, with a further 42.9% in the very low normal range. Only one patient had beriberi heart disease. Idiopathic dilated cardiomyopathy was the main cause of cardiac failure. It is suggested that excessive alcohol consumption is an important factor contributing to cardiac morbidity in urban blacks.

Recent work has shown that several folates interact with excitatory kainic acid receptors in the mammalian brain and appear to have agonist activity at these receptors. Since kainic acid is a potent neurotoxin it is possible that folates share this toxicity and that high levels of folates result in neuronal damage. Levels of methyltetrahydrofolate are markedly elevated in vitamin B12 deficiency, a disease associated with neuronal destruction. We propose that this destruction occurs as a result of a neurotoxic action of methyltetrahydrofolate. Injection of kainic acid into the basal ganglia of experimental animals produces a pattern of damage similar to that found in patients dying of Huntington's chorea. It is possible that the underlying defect in this disease resides in the pathways of folate metabolism such that a neurotoxic excess of folates accumulates in the central nervous system. Such a disease process might be arrested by antifolate drugs.

Dietary intake of thiamin has been evaluated in a series of 615 eleven-year-old children in Western Cape Province, South Africa. Thiamin intakes, determined by 24-hour recall and local food composition tables, were highest in rural white children (boys 1.49 mg/day, girls 1.11 mg), followed by rural black (Xhosa) children (1.33, 1.15 mg), and lowest in rural (1.18, 1.11 mg) and urban coloured (Euro-African-Malay) subjects (1.11, 0.85 mg). The group means exceeded WHO recommended daily intakes except for urban coloured girls. Thiamin nutritional status was determined by automated microbiological assay of thiamin in erythrocytes in a subsample of 69 children. One urban coloured child was thiamin deficient. The highest mean value (69.4 micrograms/l) was found in rural coloured children, followed by their urban counterparts (64.8 micrograms/l) and black rural children (63.6 micrograms/l). Rural white children had the lowest mean value (60.3 micrograms/l). In general, thiamin stores in these children appear to be adequate.

1. 1. Haematological values and iron status of wild and captive fruit bats (Rousettus aegyptiacus) were determined. 2. 2. Plasma iron concentrations were 175μg/dl in wild males, and 286–316 μg/dl in captive bats. 3. 3. Total splenic stores were small (around 100 μg) in relation to hepatic stores (3 mg) and total haem iron (2.6 mg). 4. 4. Haemoglobin levels, red cell counts and haematocrits were unusually high and mean corpuscular volumes low. 5. 5. Lactating wild bats showed no deficits in iron status or in haematological values. 6. 6. It is concluded that the ascorbic acid content of fruit, together with the bats' high food requirement, has ensured an ample iron supply in this vegetarian species.

The fruit bat Rousettus aegyptiacus develops cobalamin deficiency when exposed to the gas nitrous oxide (N2O). The effect of dietary methionine (600 mg/kg fruit) or L-3, 4-dihydroxyphenylalanine (L-dopa, 100 mg/kg body weight daily) on brain and liver S-adenosylmethionine (AdoMet) concentrations, and on the neurological impairment was studied. Methionine supplementation significantly delayed the onset of neurological impairment (p less than 0.01) and resulted in a 2.4 fold increase in liver AdoMet levels. Brain AdoMet levels were unchanged. L-dopa, which is methylated by means of AdoMet did not aggravate the N2O-induced neuropathy but did lower, albeit insignificantly, brain AdoMet levels. The results do not support the hypothesis that the neurological impairment and death in cobalamin inactivated bats is a result of a depletion of methionine or AdoMet in the nervous system.

The prevalence of anaemia and deficiencies of iron, folate and vitamin B12 were investigated in 140 rural black preschool children aged 3-5 years living in five different villages in the Letaba area, near Tzaneen. Anaemia was highly prevalent, 39.2% of the children having haemoglobin levels below 11.1 g/dl. Approximately 10% were considered to be iron-deficient. On the basis of subnormal red cell folate values, 1 in 4 children was folate-deficient, suggesting the need for intervention at the community level such as enrichment of the staple foodstuff, maize meal, with folic acid.

To combat vitamin deficiencies in populations whose dietary staple is maize, the fortification of maize meal with riboflavin and nicotinamide has been recommended. Subsequently, part of the milling industry has voluntarily fortified the meal with these two vitamins. In the present study, the concentrations of added riboflavin and nicotinamide were determined by high-performance liquid chromatography in 43 samples from a wide area. With the exception of three samples, concentrations of these vitamins were below the recommended level, and most were less than half this amount. Fortification programmes require regular monitoring by an independent authority.

Ferritin levels in serum and milk were investigated in series of 15 urban and 18 rural black mothers. No mother was anaemic. Mean serum ferritin levels in the urban and rural groups were 57 +/- 55 ug/l and 25 +/- 28 ug/l (mean +/- SD). Corresponding milk ferritin concentrations were 21 +/- 22 ug/l and 29 +/- 30 ug/l respectively. The significance of ferritin in human milk is discussed.

Some indices of nutrition have been examined in hostel- and non-hostel-dwelling groups of industrially employed black males. Hostel-dwellers in the large metropolitan areas have to prepare their own food and many are accustomed to excessive alcohol intake, especially of sorghum beer. In the two groups studied, blood levels of vitamin B12, folate, pyridoxal and albumin were similar, but erythrocyte thiamine levels were significantly lower in the hostel-dwellers. Although the proportion of subjects with elevated levels of gamma-glutamyltransferase, an index of alcoholic liver disease, was similar in the two groups, thiamine-deficient hostel-dwellers had a greater proportion of elevated values suggesting that thiamine deficiency was related to both inadequate diet and excessive alcohol consumption. Fortification of sorghum beer with thiamine might prevent or reduce thiamine deficiency in this group. The cost would not materially affect the price of the beer.

The fruit bat Rousettus aegyptiacus, when exposed to nitrous oxide (N2O) for 8-10 weeks develops cobalamin deficiency and neurological impairment leading to ataxia and death. We report the lipid composition of cerebral tissue of control animals and impaired animals following exposure to N2O, with or without dietary folic acid supplements. There were no statistically significant differences in the concentrations of total lipids, phospholipid, glycosphingolipid, plasmalogen and cholesterol between the different groups, although the ratio of choline phosphoglyceride to ethanolamine phosphoglyceride in N2O exposed animals was slightly lower than in controls. Bats exposed to N2O showed slightly higher levels of the fatty acid linoleate (18:2) in their phosphatidylethanolamine relative to arachidonate (20:4) compared with controls. This increase tended to be more pronounced in the bats receiving dietary folic acid supplements (but p greater than 0.05).

The consumption of indigenous cereal-based fermented beer is widespread throughout Africa and other parts of the world. In some countries such beer is brewed commercially as well as at home. As evidence of beri-beri may occur in habitual consumers of the beer, the thiamin content of beer brewed commercially from a mixture of sorghum and maize was investigated. Thiamin concentration in beer averaged 0.33 mg/l, with more than 95% in the cellular fraction, mainly live yeast cells. The thiamin in the cells is not generally available for absorption and the cells take up thiamin added to the beer. At low concentrations (0.25-0.5 mg/l) up to 90% of added 14C-thiamin was taken up by the cells but with concentrations in excess of 2.5 mg/l, the uptake was less than 30%. These results indicate that fortification of sorghum beer with thiamin is feasible. The addition of 2.5 mg/l would supply up to 1.6 mg of absorbable thiamin and thus meet the recommended daily allowance in the target group of habitual consumers.

Eight healthy subjects were fed a diet containing 1–4 g eicosapentaenoic acid (EPA) daily for 8–21 days. The EPA was derived from 300–400 g per day of sardines, pilchards, herring and/or kabeljou. Sources of arachidonic acid (AA) in the diet were reduced. At the end of the experimental period there was an increase in the ratio of EPA to AA in the platelets and a decrease in platelet aggregation to ADP, epinephrine and collagen. Aggregation to AA was not reduced. Thromboxane production in response to all four agonists was reduced. Serum total and HDL cholesterol levels fell significantly but platelet counts, LDL cholesterol and triglyceride values did not change. We conclude that even a relatively modest intake of EPA derived from a mixed fish diet together with a reduction in AA intake can alter in vitro platelet function and serum lipids significantly. A long term controlled trial of a palatable mixed fish diet to assess possible antithrombotic and antiatherogenic effects is justifiable.

Thiamin status and biochemical indices of malnutrition and alcoholism have been studied in groups of settled !Kung San living in the northern Kalahari Desert of Namibia. One third of the men and 20% of the women had low red cell thiamin concentrations. Raised serum gamma glutamyl transferase (gamma GT) activities were present in 30% of the men and 11% of the women. gamma GT activities were negatively correlated with red cell thiamin concentrations (r = -0.321, P less than 0.01). Raised mean corpuscular volumes were observed in over half the subjects. Anaemia was rare. Plasma protein and albumin concentrations were satisfactory. Cholesterol concentrations were relatively low (mean 4.1 mmol 1-1). The present results identify a high prevalence of thiamin deficiency in settled !Kung San, and suggest that alcohol abuse is the main contributory factor.

1. 1. Synaptosomes were prepared from the brain of cobalamin deficient and cobalamin supplemented fruit bats (Rousettus aegyptiacus) by a floatation method on a discontinuous sucrose gradient. 2. 2. There were no significant differences in fatty acid composition between the deficient and supplemented bats. 3. 3. The odd chain fatty acid 15:0 amounted to 0.2% of the total fatty acids in both groups. 4. 4. We conclude that the fatty acids of synaptosomal lipids are not a factor in the development of neural dysfunction in the cobalamin deficient fruit bat.

A study was performed in 100 subjects to determine the prevalence and cause of anaemia in pregnant Indian women in the Johannesburg area. The geometric mean serum ferritin concentration in all three trimesters of pregnancy was below 12 micrograms/l, with 43.3% of women in the first, 48.6% in the second and 80.0% in the third trimester having concentrations below this value. Estimation of body iron stores revealed a mean deficit of 265 mg iron in subjects in the third trimester, 20% of whom had iron deficiency anaemia. No difference in iron status was demonstrable in subjects from different religious backgrounds. Folate and vitamin B12 nutrition was adequate. Three subjects were diagnosed as being beta-thalassaemia heterozygotes. The findings underline the need for routine iron supplementation of pregnant Indian women in the Johannesburg area.

Myelin was isolated from the brain of adult fruit bats (Rousettus aegyptiacus) in a discontinuous sucrose gradient. Cholesterol comprised 189.0 mol/100 mol lipid phosphorus, galactolipids 60.3 mol/100 mol phosphorus and plasmalogens 32.5 mol/100 mol phosphorus. Choline and ethanolamine glycerophosphatide were present in nearly equal amounts followed by serine glycerophosphatide, sphingomyelin and inositol glycerophosphatides. The fatty acid composition of sphingomyelin and non-hydroxy cerebroside was determined by gas-liquid chromatography. Fatty acids were mainly saturated or mono-unsaturated with a small percentage of polyunsaturated fatty acids present. The lipid composition and sphingolipid fatty acid distribution in bat myelin was fairly similar to that of other species.

The rate of absorption of 14C-thiamin added to sorghum beer has been studied in isolated loops of rat duodenum and adjacent jejunum. Appreciable amounts of the vitamin were absorbed in spite of the presence in the beer of alcohol and live yeast cells avid for the vitamin. These results suggest that commercially brewed sorghum beer, a beverage consumed widely by Third World populations, can be fortified with thiamin to prevent the development of deficiency of the vitamin in habitual consumers of the beer.

The nutritional status of 145 black preschool children aged 3-5 years living in Letaba near Tzaneen was evaluated biochemically; 20.7% weighed less than 80% of the 50th percentile. Mean levels of red cell thiamine, serum protein and albumin, 25-hydroxyvitamin D, alkaline phosphatase, calcium and phosphorus were similar in underweight children and children not classified as underweight. The precise bearing of slower growth and associated biochemical parameters on present and future health needs elucidation.

Niacin status was evaluated in groups of school children (n = 25) in Transvaal Province, South Africa, by measuring the urinary excretion of the metabolite 2-pyridone. In an urban Indian group of low socioeconomic status, and a white middle-class group, 12% and 4% respectively exhibited low or deficient levels of the metabolite. In a rural black village, 28% had evidence of low or deficient levels of niacin, even though two of the 3 locally available brands of maize meal (their dietary staple) claimed to be fortified with nicotinamide. It is concluded that external monitoring of the voluntary maize meal fortification scheme will be necessary to effectively combat deficiency of niacin in traditional maize meal consumers.

A nutritional anaemia survey was carried out on 610 11-year-old coloured, black and white schoolchildren in urban and rural communities in the western Cape. The mean (+/- 1 SD) haemoglobin concentration was 13.0 +/- 1.2 g/dl. The coloured and black subgroups considered together had a significantly lower mean haemoglobin concentration than the white subgroup (12.8 +/- 1.2 g/dl v. 13.4 +/- 1.0 g/dl) (F = 37.47; P less than 0.0001). The urban population as a whole had a significantly lower geometric mean (1 SD range) serum ferritin concentration than the rural population (25.6 (13.5-48.6) micrograms/l v. 34.1 (21.3-54.6) micrograms/l) (F = 42.94; P less than 0.0001). The lowest geometric mean serum ferritin values were found in the urban coloured (23.1 (11.5-46.4) micrograms/l) and urban black schoolchildren (23.7 (13.2-42.6) micrograms/l), with figures of less than 12 micrograms/l in 11.7% and 12.5% respectively. Although 28% of the children had red cell folate values below the recommended lower limit of normal (175 ng/ml), probability plot analysis of the data suggested that folate deficiency was not a major problem in the study population. The calculated daily iron and folate intakes were below the age-related recommended dietary allowance (RDA) in all the subgroups, yet anaemia was relatively uncommon. These findings suggest that the RDA values are too high. Overall the prevalence of nutritional anaemia was low and only the urban coloured subgroup showed significant second populations with low haemoglobin and serum ferritin measurements.

A nutritional anaemia survey was carried out in 224 pregnant coloured first-time attenders at Coronation Hospital antenatal clinic in Johannesburg during the second quarter of 1986. None had received any form of nutritional supplementation during pregnancy. Haemoglobin concentrations less than 11 g/dl were present in 18.9% of women in the third trimester of pregnancy, while 64% had a saturation of transferrin value of less than 16% and 68% a serum ferritin level less than 12 micrograms/l. Calculations suggested that mean iron stores in the first trimester were 228 mg, with 37.5% of women having absent stores. Comparable figures in the second and third trimesters were 74 mg and -92 mg respectively. The fact that many were iron deficient in the first trimester indicates a high frequency of iron deficiency in non-pregnant women in this population group. Although 20.8% of the women had red cell folate values below the normal range for non-pregnant subjects, folate deficiency did not appear to be a significant problem. Vitamin B12 deficiency was very uncommon.

[2-14C]Tetrahydropteroylglutamic acid and 5-[G-3H]methyltetrahydropteroylglutamic acid were given intraperitoneally to fruit bats. Folate polyglutamates were formed in the liver from both substrates in different amounts and at different rates. The methylfolate pool appeared to remain separate from the tetrahydrofolate pool. More polyglutamate was formed from tetrahydropteroylglutamic acid than from 5-methyltetrahydropteroylglutamic acid. There was a fall in the folate content of the liver in the vitamin B-12-deficient bat and a more rapid incorporation of folates into polyglutamates but thereafter a more rapid loss of the labelled folate from liver.

Fatty acid composition of mature human milk of rural and urban black South African mothers was determined by gas-liquid chromatography. Rural mothers consumed traditional diets low in animal protein and fat, and high in carbohydrate and fibre. Urban mothers consumed more varied, partially westernized diets, and two-thirds were overweight. Plasma cholesterol concentrations were significantly lower in the rural group (3.64 vs 4.75 mmol/l, P less than 0.01). Milk of rural mothers contained significantly higher percentages of C10:0, C12:0, and total saturated fatty acids. Fatty acids C8:0-C14:0 synthesized de novo in the mammary gland were substantially higher in the milk of the rural mothers (24.7 vs 15.9 per cent). Conversely, the milk of the urban group contained higher percentages of monounsaturated fatty acids, 18:3 omega 3 and 20:2 omega 6. The ratio of polyunsaturated to saturated fatty acids in rural samples was 0.36 +/- 0.13 compared to 0.41 +/- 0.15 in urban samples (P greater than 0.1). It is concluded that maternal dietary intake significantly affects milk composition, as demonstrated by the high percentages of fatty acids synthesized de novo in the mammary gland of rural mothers habituated to low-fat, high-carbohydrate intakes.

An electrical apparatus was designed to record continuously the feeding activity of either a colony of 30 fruit bats (Rousettus aegyptiacus) or single bats in captivity. The endogenous feeding activity rhythm was synchronized by change in the external light-dark cycle. During June to August (winter), the bats consumed an average of 96 g sliced banana, equal to 76 g wet weight/100 g body weight per 24 hours or 15 g dry weight/100 g body weight per 24 hours. The feeding period began shortly after sunset and continued for 10,6 h. Feeding consisted of 6-14 separate small meals. The mean or overall feeding rate was 9,1 g banana/h, and the feeding rate during the first 3 h, 13,1 g/h. The bat regulated its food intake by varying the rate of food consumption and not by changing the duration of the feeding period. It is suggested that clustering of the bats may influence the caloric intake by reducing the energetic cost of thermoregulation.

1. The effect of methylcobalamin inactivation by the gas nitrous oxide on plasma amino acid and tissue methionine levels in fruit bats (Rousettus aegyptiacus) was examined.2. Animals exposed to N2O-oxygen (1:1, v/v) for 90 min daily received a fruit diet with or without methionine or betaine supplements. Exposure and diets were continued for up to 17 weeks or until neurological impairment and muscular weakness was established.3. All the groups exposed to N2O had significantly lower liver, brain and plasma methionine concentrations except the methionine-supplemented animals which showed significantly raised levels. Plasma homocysteine, which was absent in controls, was present in all the N2O-exposed groups.4. Betaine supplementation resulted in reduced accumulation of homocysteine in plasma. However, plasma and liver methionine levels were only slightly increased compared with animals on the basal diet, and brain methionine levels were the lowest of all the groups studied.5. These results support the hypothesis that reduced methionine synthesis is an important contributor to the development of neurological impairment in this species and suggest that dietary supplementation with the methionine precursor betaine cannot replace the loss of vitamin B12-dependent methionine synthesis.