Utilization of urea nitrogen in Papua New Guinea highlanders

The utilization of urea nitrogen was examined in 10 healthy adult men from a village near Lufa, in the Eastern Highlands Province of Papua New Guinea. The staple diet of these men was sweet potatoes. [15N]urea was used as tracer for urea released into their intestinal tracts and the utilization of the urea-N was estimated from the trend of 15N. The men were orally given [15N]urea at the beginning of the study and then their daily protein intake, serum protein levels, 15N excretion in the feces and urine, 15N retention in the whole body and 15N incorporation into serum protein were examined. Their daily protein intake (32.2 +/- 8.6 g/day) was low, but their serum protein level (8.05 +/- 0.41 g/100 ml) was within the normal range. 15N retention in the whole body on day 3 was estimated to be 35.4 +/- 20.2% of the total amount administered, calculated from the recoveries in the feces (1.64 +/- 0.85%) and urine (63.0 +/- 20.5%) on days 1-3. The utilization of urea nitrogen in Papua New Guinea highlanders was confirmed from the finding of 15N incorporation into serum proteins on day 3 (0.008 +/- 0.005 atom% excess). This incorporation was negatively correlated with the urinary nitrogen excretion and serum protein level. This correlation suggests that Papua New Guinea highlanders with low urinary nitrogen excretion or a low level in serum protein, who are in a poor state of protein nutrition, tend to utilize more urea nitrogen for the synthesis of serum protein.     

Studies of nitrogen balance in male highlanders in Papua New Guinea

Nitrogen metabolism in Papua New Guinea highlanders was studied by examining their nitrogen balance when they ate their usual diet (experiment 1) or an experimental diet (experiment 2). Studies were made on 39 male highlanders between October and December in 1980 and 1982. In experiment 1, the average protein and energy intakes (mean +/- SD) for three consecutive days of usual diets were 116.2 +/- 31.2 mg N/kg body weight and 46.9 +/- 8.9 kcal/kg body weight in 1980 and 143.5 +/- 54.8 mg N/kg body weight and 47.3 +/- 10.5 kcal/kg body weight in 1982, and thus the nitrogen balances were 27.7 +/- 28.3 and 18.4 +/- 24.2 mg N/kg body weight, respectively. Most dietary protein and energy was derived from sweet potatoes and other vegetable foods, but between 1980 and 1982 the diet changed slightly with increased consumption of imported foods such as rice and canned fish. In the second experiment, when 10 highlanders were given adequate protein diet (about 200 mg N/kg body weight and about 44 kcal total energy/kg body weight for 13 d, much of the dietary nitrogen was retained in their bodies (45.1 +/- 19.3 mg N/kg body weight). When another group of men were fed a sweet-potato diet (81.1 mg N/kg body weight for 8 d followed by a low protein sweet-potato diet containing only 42 mg N/kg body weight with 50 kcal/kg body weight for 14 d, nitrogen true digestibility and net protein utilization increased and their nitrogen balance showed no significant change (-11.0 +/- 5.6 mg N/kg body weight).(ABSTRACT TRUNCATED AT 250 WORDS)     

Basal metabolic rate and energy costs at rest and during exercise in rural- and urban-dwelling Papua New Guinea highlanders

OBJECTIVE: (1) To evaluate inter-individual variations, regional and sex differences in the basal metabolic rate (BMR) and related variables; (2) to compare measured BMR with estimated BMR using predictive equations; and (3) to examine the net mechanical efficiency (NME) in step tests. DESIGN: BMR and energy costs at rest and during step tests were measured by the Douglas bag technique of indirect calorimetry. NME was calculated from BMR and energy costs of step tests. SETTING: Rural villages under subsistence agriculture and urban settlements under cash economy. SUBJECTS: Adult males and females (n=33) including 16 rural villagers and 17 urban migrants. Interventions: Step exercise test. RESULTS: There were significant regional differences in BMR (per body weight) in both sexes. The BMR predicted by Schofield equation correlated with the measured BMR (-1 to+3%), while the BMR predicted by Henry and Rees equations under-estimated the measured BMR by 6-11%. NME was higher in urban subjects with larger body size than in rural subjects for both sexes, albeit insignificantly. NME tended to be higher with increased stepping level in both sexes. CONCLUSIONS: Urban migrants had lower BMR than rural dwellers, and the BMR predicted by Schofield equation correlated with the measured BMR in both sub-groups.     

Responses of sodium balance, blood pressure, and other variables to sodium loading in Papua New Guinea highlanders

For determination of the responses of sodium balance, blood pressure, and other relevant variables to Na loading in people with a low intake of Na, 10 male Papua New Guinea highland subjects were given additional Na at two levels (128 and 256 mmol/d) for 10 d after a 3-d control period of low-Na diet. Na loading caused a marked positive balance of Na, decreases of aldosterone concentration and renin activity in the plasma, and a decrease of urinary aldosterone excretion. The blood pressure, particularly that measured at noon, increased in the latter half of the Na-loading period, the increase being significant in the group given 256 mmol of sodium daily: the systolic and diastolic blood pressure increased from 92 +/- 8 over 56 +/- 7 mm Hg in the control period to 102 +/- 7 over 60 +/- 4 mm Hg in the latter half of the test period (p less than 0.05).     

Health services in Papua New Guinea

The government of Papua New Guinea has been committed since independence to providing primary health care to its entire population through a government-operated national health system. In spite of geographic, cultural, and linguistic barriers, most people have access to primary health services and major indicators of the health of the population have improved. However, deficiencies in the provision of preventive services exist and common infectious diseases, particularly malaria, are still the main causes of morbidity and mortality. Economic realities dictate that improvements in health status in the immediate future will have to come through improved productivity and quality of services rather than expansion of the health care system.     

Congenital malaria in Papua New Guinea

The incidence of malarial infection in pregnant women at delivery, their corresponding infants and umbilical cords and a control group of non-pregnant women were investigated in the Madang region of Papua New Guinea. Anti-malarial antibody titres were measured in maternal and paired cord sera. Parasitaemia occurred in 18/73 (24.7%) of non-pregnant females compared with 15/51 (29.4%) of pregnant females. Malarial parasites were found in 7/48 (14.6%) cord blood samples and in 4/52 (7.7%) samples of the infant's peripheral blood, indicating transplacental transmission. Infection with Plasmodium falciparum was commoner in pregnant than non-pregnant females, and accounted for all the cord and infant infections. A significant correlation was found between anti-malarial IgG antibodies in paired maternal and cord bloods. There was an association between umbilical cord infection and low levels of cord antibody. Clinical malaria developed in at least one out of the 7 cases in which placental transfer of parasites was known to have occurred. This study suggests that transfer of parasites across the placenta is a common event in Papua New Guinea. Further consideration should be given to treatment with anti-malarial drugs of infants with cord or peripheral blood parasitaemia or, indeed, of all infants of mothers with parasitaemia.     

Protein content and amino acid scores of sweet potatoes in Papua New Guinea Highlands

Protein content and amino acid scores of sweet potatoes were determined in Papua New Guinea Highlands where sweet potatoes contributed approximately 50% of the total protein intake. Major cultivars of sweet potatoes in the Tari basin and the Asaro valley, 15 in total, were sampled and their nitrogen and amino acid contents were analyzed. Sweet potatoes in the Tari basin and the Asaro valley contained, respectively, 1.4% and 0.8% of protein in fresh weight basis. The concentration was 1.7 times higher in the former than in the latter (t‐test, p < .01). The first limiting amino acid was leucine in the samples from both areas and amino acid scores were 87 in the Tari samples and 85 in the Asaro samples, using values of FAO/WHO (1973). Protein content and amino acid scores of sweet potatoes in the Tari basin were higher than those previously reported in Papua New Guinea Highlands probably because of introduction of new cultivars in recent decades, and thus protein intake of the inhabitants may have been increased.     

Effects of low protein intake on protein metabolism of Papua New Guinea highlanders studied with [15N]glycine

The effects of low protein intake on protein metabolism, including the size of pools and the protein synthesis rates, were studied by use of [15N]glycine in Papua New Guinea highlanders. Studies were made on 9 men between October and December in 1982. In experiment 1, two subjects were given a protein-free diet (PFD) containing 49.1 kcal/kg of energy. In experiment 2, subjects were given a sweet-potato diet (SPD) containing 45.4 kcal/kg of energy and 0.507 g/kg of protein for 8 days, and then were given a low-protein sweet-potato diet (LPSPD) containing 50.0 kcal/kg of energy and 0.265 g/kg of protein. During the SPD period, the sizes of the metabolic and active protein pools (mean +/- SD) were 270 +/- 134 mgN/kg and 362 +/- 107 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 463 +/- 161 mgN/kg/day and 299 +/- 38 mgN/kg/day, respectively. During the LPSPD period, the sizes of the metabolic pool and active protein pool were 131 +/- 64 mgN/kg and 378 +/- 106 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 490 +/- 206 mgN/kg/day and 280 +/- 26 mgN/kg/day, respectively. The protein metabolism in the LPSPD showed no significant difference from the SPD. The results suggest that, when the energy levels were approximately the same, protein metabolism in Papua New Guinea highlanders was maintained in spite of the decrease in protein intake.     

Protection of breastfeeding in Papua New Guinea

In Papua New Guinea the bottle-feeding of babies has been increasing, predominantly among unemployed women of low educational status. Many women are unaware of their legal right to have breaks at work for the purpose of breastfeeding, and a high proportion of workplaces have no facilities for mothers who wish to breastfeed their children. The laws on the feeding of infants should be updated and implemented, and an effort is needed to explain the benefits of breastfeeding and the rights of working mothers.     

Country watch: Papua New Guinea

Senior lecturers, students, the Dean of the Arts Faculty, university administrators, and a nongovernmental organization called PNG Trust are working together on an AIDS Awareness Committee at the University of Papua New Guinea. They dispense educational materials to staff and students to increase awareness and provide advice on safer sex practices. The orientation book for new and continuing students contains selections from the committee's materials. A social scientist on the committee has conducted a pre-intervention survey to determine the knowledge, attitudes, beliefs, and practices of students. The intervention consists of four weeks of video showings and discussions. The post-intervention survey will take place later in 1995. Committee members, the university clinic, the student services office, female dormitories, and the university staff bar distribute free condoms on request, especially to students, who are on limited scholarships. The committee has developed an HIV/AIDS policy for the university that has been sent to the University Council for approval. The policy contends that protective and preventive approaches to HIV/AIDS are restatements of existing health, safety, and human rights codes. Recommendations in the policy include prevention of discrimination, confidentiality of all records, rejection of mandatory HIV testing of staff and students, and provision of appropriate medical care for students who tell the university health services of a positive HIV status. Assuming it is approved, the policy will apply to all university campuses in Papua New Guinea. The committee would like the university, after policy adoption, to provide them with a room as a resource center and to incorporate social work students in a counseling service. Students can volunteer to operate a telephone helpline and photocopy educational materials.     

Iodine deficiency in Papua New Guinea (sub-clinical iodine deficiency and salt iodization in the highlands of Papua New Guinea)

Data on the status about iodine nutrition in children in Papua New Guinea (PNG) are scarce. This study attempts to determine the mean daily per capita consumption of salt, the iodine content of salt in the households and retail shops and the urinary iodine concentration in children (6-12 years) in Hella Region, Southern Highland Province (SHP), PNG. The mean daily consumption of salt was 2.62 +/- 1.29 g. The iodine content of salt was >30 p.p.m. in 95 per cent of households and 100 per cent of retail shops. The median urinary iodine concentration of 48.0 mg/l for all the children indicates moderate iodine deficiency. The median urinary iodine concentrations for the male (67.0 mg/l) and female (44.0 mg/l) children indicate mild and moderate iodine deficiency, respectively. 68.42 per cent of the male and 81.82 per cent of the female children have urinary iodine concentration <100 mg/l, indicating that iodine deficiency is a potential public health problem in the Hella region. These results indicate a need for further assessment of the implementation of the universal salt iodization strategy for the elimination of iodine deficiency in the SHP, PNG.     

Subsistence agriculture and child growth in Papua New Guinea

Spatial statistical analyses of child anthropometric data were undertaken to assess the influence of systems of subsistence agriculture, in terms of staple foods and cash crops cultivated, on patterns of child growth in Papua New Guinea. These agricultural data explained between a quarter and half of the geographical variation in anthropometric growth indicators. Accounting for differences in altitude, relief and rainfall patterns, though explaining additional geographical variation, did not improve the predictions. Child growth was better in agriculture systems with cassava and sweet potato as staple crops, but worse in systems where banana, sago and taro were staple crops. Both the cultivation of all major cash crops, and sales of fish and food crops improved child growth. More intensive agricultural systems were associated with larger children indicating that the nutritional status of children benefited from intensification as well as from the introduction of cash crops into traditional subsistence systems.     

Ross River virus arthritis in Papua New Guinea

In 1975 it was reported that antibodies to Ross River virus (RRV) were present in the sera of many population groups in Papua New Guinea. We describe here 3 cases of polyarthritis that occurred in Port Moresby, the capital of Papua New Guinea, during 1980-81 and in which the diagnosis of RRV infection was confirmed by serological tests, and 3 other cases in which serological tests suggested RRV infection but were not diagnostic. A possible case of fatal RRV encephalitis is also reported.     

Men's extramarital sexuality in rural Papua New Guinea

Married women in rural Papua New Guinea are at risk for HIV primarily because of their husbands' extramarital relationships. Labor migration puts these men in social contexts that encourage infidelity. Moreover, many men do not view sexual fidelity as necessary for achieving a happy marriage, but they view drinking and "looking for women" as important for male friendships. Although fear of HIV infection is increasing, the concern that men most often articulated about the consequences of extramarital infidelity was possible violent retaliation for "stealing" another man's wife. Therefore, divorced or separated women who exchange sex for money are considered to be "safe" partners. Interventions that promote fidelity will fail in the absence of a social and economic infrastructure that supports fidelity.     

Distribution of Angiostrongylus cantonensis in Papua New Guinea

Examination of 97 rats trapped in Port Moresby and Lae on the mainland of Papua New Guinea and in Rabaul, East New Britain Province, showed that 12.4% were infected by Angiostrongylus cantonensis. Larval An. cantonensis were found in Achatina fulica snails collected at these towns, from the Ramu Valley near Madang on the mainland and at locations in West New Britain, New Ireland and Bougainville Island. The mollusc infection rates ranged from 12.7% at Port Moresby to 32.4% at Kimbe in West New Britain (mean: 19.2%). Larvae obtained from snails from Port Moresby, Lae, the Ramu Valley and Rabaul were fed to laboratory rats and mature nematodes obtained subsequently provided confirmation that the species was An. cantonensis. Ach. fulica has not yet colonized the Highland region of Papua New Guinea and rats trapped in Goroka were free of infection. Human angiostrongyliasis has now been reported from Rabaul and studies have shown a high level of immunological responsiveness to the parasite in the sera of residents of East New Britain.     

Predisposition to hookworm infection in Papua New Guinea

Reinfection with hookworm (Necator americanus) following chemotherapy was studied over 8 years in a rural village in Madang Province, Papua New Guinea. Faecal egg counts were performed on up to 202 individuals in July 1988, August 1990 and November 1996; the study population was treated after sampling in 1988 and 1990. Reinfection burdens in 1996 did not differ significantly from pretreatment burdens (in 1988), and were significantly higher than burdens in 1990. However, the prevalence of hookworm infection was significantly lower in 1996 than in either 1988 or 1990. There was significant predisposition to high or low hookworm burden between 1990 and 1996; this predisposition was stronger in children than adults. However, there was no detectable predisposition between 1988 and 1996 in individuals who had been treated 2 or more times between surveys. The mean weight of adult hookworms in individual hosts was measured in 1988 and 1990 using worms expelled after chemotherapy. There was a significant positive correlation between mean male hookworm weight in the 2 years, suggesting that individual hosts are predisposed to infection with heavy or light hookworms. These data suggest that differences in host susceptibility are involved in generating predisposition, but that longer-term variation in either exposure or susceptibility limits the period over which significant predisposition can be detected.