Population Based Reference Intervals for Common Blood Haematological and Biochemical Parameters in the Akuapen North District

Objectives : To estimate the reference intervals for commonly used blood haematology and biochemical parameters in an adult (18-55yrs) population of residents of Mampong Akuapem. Design: This was a population based cross sectional study of a randomly selected sample of the adult population of Mampong. The sample was selected from an updated census list of the Mampong area. Results: Median values (95 range) for measured parameters were established as follows: Haemoglobin; (males) 14.2 g/dl (females) 12.0 g/dl Alanine aminotransferase (ALT); (female) 19.6 U/L (males) 26.1 U/L and Creatinine; (males) 108 mmol/L (females) 93 mmol/L. Conclusion: In comparison to reference values that are commonly used in Ghana; the haemoglobulin levels from this study were lower; and liver function parameters higher. This could be a result of genetic or environmental differences and calls for the need to establish site specific reference values applicable to our population

Vaccine-modified measles in previously immunized children in Accra, Ghana: clinical, virological and serological parameters.

Despite rapidly increasing measles immunization coverage, epidemics of measles occurred from January to March 2000 in some parts of Accra, the capital of Ghana. 44 cases of acute measles were diagnosed at three health facilities during the outbreaks, which we examined clinically and serologically. The peak incidence occurred among 6-12-year-olds, clinical symptoms were milder than the typical symptoms of measles, and fever was significantly less common. None of the cases developed complications and all recovered completely. Thirty-eight (86.4%) were tested serologically; IgM antibodies were detected in 73.7% and IgG antibodies in 84.2% during the acute phase. Milder symptoms in a significant number of cases with measles IgG antibodies suggest that these are vaccine-modified measles, attributable to waning antibodies and low circulation of wild type virus in an area of high vaccine coverage. Serological confirmation will be required for accurate diagnosis, if measles is to be eradicated or kept under control. It also seems likely that multiple dose immunization schedules will be needed in the future to maintain protective antibody levels and to protect children against measles in Ghana. This will eliminate the frequent outbreaks of measles involving immunized children.

Anaemia caused by asymptomatic Plasmodium falciparum infection in semi-immune African schoolchildren.

A cohort of 250 Ghanaian schoolchildren aged 5-15 years was followed clinically and parasitologically for 4 months in 1997/98 in order to study the effect of asymptomatic Plasmodium falciparum infections on haematological indices and bone-marrow responses. Of the 250 children 65 met the predefined study criteria. Thus, 14 children were parasite-free throughout (group 1), 44 had P. falciparum in all blood samples collected but no symptoms of malaria (group 2), and 7 had 1 malaria attack during the study period (group 3). At the end of the study the mean haemoglobin (Hb) level in group 1 was 123 g/L, significantly higher than the value of 114 g/L in groups 2 and 3 (P < 0.02, adjusted for age and splenomegaly). The low Hb in group 2 was associated with subnormal plasma iron. Low Hb was associated with elevated erythropoietin (EPO) levels, and there was a positive correlation between EPO and reticulocyte counts. However, the reticulocyte response to EPO was more pronounced in uninfected than in infected children, suggesting a partial interference with erythropoiesis in asymptomatic infections. Children with asymptomatic infections had significantly higher plasma levels of tumour necrosis factor than uninfected children (geometric means 50 ng/L and 27 ng/L, respectively, P < 0.001) and this cytokine may contribute to bone-marrow suppression and disturbed iron metabolism. We suggest that asymptomatic malaria leads to a homeostatic imbalance in which erythrocyte loss due to parasite replication is only partially compensated for by increased erythropoiesis. The consequences of the reduced Hb levels on the development and cognitive abilities of children with asymptomatic infections, and the risk of precipitation of iron deficiency, deserve further study and should be considered in malaria control programmes that aim at reducing morbidity rather than transmission.

Surface marker patterns of T cells and expression of interleukin-2 receptor in measles infection.

The surface marker patterns of T cells of Ghanaian children during measles infection were studied and an attempt was made to demonstrate T cell activation and viability in vitro after activation in vivo by measles virus. The frequencies of CD4+ and CD8+ naive T cells in measles patients were high while their memory T cells were remarkably reduced with no sign of proliferation even at the acute phase of the illness. The reduction of memory T cells was prolonged during the convalescent phase (2 months after onset). The anti-CD3 monoclonal antibody-induced expression of interleukin-2 receptor alpha chain (IL-2R/CD25) was significantly suppressed; however, the addition of phorbol 12-myristate 13-acetate or ionomycin caused a remarkable recovery of CD25 expression. On simple culture, an appreciable proportion of T cells from measles patients died rapidly in contrast with only a few T cells from healthy controls doing so. The suppression of CD25 expression was still demonstrated during the convalescent phase of the disease. Taken together these results suggest unresponsiveness and activation-induced cell death of T cells during severe measles infection in Ghanaian children. Furthermore the prolonged abnormalities of T cells (i.e. decreased memory T cells and inhibition of CD25 expression during the convalescent phase) might be related to post-measles infection immunosuppressive status.

Lead levels and related biochemical findings occurring in Ghanaian subjects occupationally exposed to lead.

Blood and urine lead levels in relation to blood delta-aminolevulinic acid dehydratase (ALAD) activity and also blood and renal status were evaluated in lead smelters, automobile mechanics and gasoline retailers in the city of Accra, Ghana. Relationship between high blood lead levels (mean: 108 ug/dl) and low ALAD activity (mean: 74.3 units) indicating lead over exposure was found in the lead smelters. Non-toxic lead exposure was, however, noted in the automobile mechanics and the gasoline retailers. Their respective mean blood lead levels were 27.8 ug/dl (mean blood ALAD activity 212.5 units) and 8.6 ug/dl (ALAD: 239.9 units). Personal habits at the work place appear to play a major role in facilitating exposure to lead among all the three groups of workers in addition to lack of control measures at the work place of the lead smelters to protect them against lead exposure. Anaemia was found in 48% of the lead smelters, 12.5% of the gasoline retailers but in none of the automobile mechanics. When compared with lead free subjects (mean blood ALAD activity: 270.9 units), urine microalbumin was significantly (p < 0.01) raised in all the lead smelters suggesting that they may be prone to renal glomerular damage. Plasma creatinine, BUN and uric acid were raised in only one of the lead smelters. The data supports the establishment of blood ALAD activity level at 100 units or less as indication of excessive body lead.

Immunological unresponsiveness and apoptotic cell death of T cells in measles virus infection.

The phenotypic alterations associated with T cells during measles virus infection have been demonstrated and an attempt has been made to show programmed cell death (PCD) of T cells activated in vivo. During the acute phase of illness, activated T cells increased rapidly. Memory T cells (CD45RO+), especially CD8+ memory T cells also tend to increase. During the recovery phase, CD8+ T cells declined rapidly, and naive (CD45RA+) T cells increased in numbers. The anti-CD3 monoclonal antibody-induced expression of interleukin-2 receptor (CD25) was suppressed. However, the addition of phorbol 12-myristate 13-acetate (PMA) caused the significant recovery of CD25 expression. In addition, PCD of activated T cells from measles patients was induced in culture. After triggering of the T cell receptor-CD3 complex, cells became more susceptible to PCD. Interestingly, the addition of PMA could inhibit PCD of activated T cells. Taken together, these data suggest unresponsiveness and activation-induced cell death of T cells during the primary response to measles virus antigens, depending on the activation status of protein kinase C.

Decreased cysteine and glutathione levels: possible determinants of liver toxicity risk in Ghanaian subjects.

Cysteine, methionine, vitamin A, beta-carotene and glutathione (GSH) are known to protect body tissues against oxidative damage and inflammation but their value as protection against liver inflammation in tropical areas has received little attention. Blood levels of these nutrients were measured in Ghanaian volunteers with (Group 2) or without (Group 1) increased lipid peroxidation and signs of liver inflammation, as indicated by blood malonic dialdehyde, serum alpha 1-antitrypsin and triglyceride levels, and the alpha 1-acid glycoprotein:pre-albumin ratio. Serum levels of cysteine and blood glutathione were significantly lower (P < 0.02) in group 2 than in group 1 volunteers. In contrast, serum levels of methionine, vitamin A and beta-carotene were similar in both groups. Deficits in cysteine and glutathione may increase the risk of liver toxicity from oxidants in Ghanaians.

Comparative effects of aflatoxins G1 and B1 at levels within human exposure limits on mouse liver and kidney.

ddy mice were exposed to aflatoxins B1 and G1 via their feed (4.8 ng AFG1, 0.8 ng AFB1 or both/kg body wt./day) while in utero. At six months of age, hepatorenal studies were carried out. The AFG1 caused significant accumulation of only neutral fat in the liver, a slight rise in serum triglyceride and intensified hepatorenal inflammation, necrosis and bile duct proliferation. The AFB1, caused the accumulation of both neutral fat and fatty acids in the liver, and was cytotoxic to the liver and kidney. Iron storage of the liver, hematological indices, serum total protein and albumin levels were not affected by the aflatoxins.