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Biomedical subjects

E M Essien

Publications and source records attributed to E M Essien.

At least 19 recordsLinked to original sources
PubMed1995

Decrease in platelet survival and total platelet sialic acid concentration in rats infected with Plasmodium bergei bergei.

Suckling Wistar rats aged 3-5 weeks were infected through their dorsal tail vein with P. berghei berghei passed in Swiss albino mice. Platelet recovery and platelet survival using 51Cr-labelled heterologous platelets obtained from adult Wistar rats were determined in the infected animals on different post-infection days and on a group of non-infected rats as controls. Total platelet sialic acid was also determined in the same groups of animals. The results showed reduced platelet recovery, shortened survival and reduced total platelet sialic acid content in the infected animals compared with control values. The reduction in total platelet sialic acid content was related to the degree of parasitaemia and reached significant levels on the 5th post-infection day. It is concluded that the shortened platelet survival and reduced total platelet sialic acid content observed in the P. berghei infected rats were causally related and may account for the thrombocytopaenia reported in experimental and natural malaria infections of animals and man.

Animals↗
PubMed1995

Effect of Plasmodium falciparum malaria on plasma fibrinopeptide-A (FpA) concentration.

Plasma Fibrinopeptide-A (FpA) concentrations were determined using Enzyme-linked Immunosorbent Assay (ELISA) in patients with acute Plasmodium falciparum malaria infection and in 30 healthy controls. The mean FpA levels of the malaria patients were significantly raised (p < 0.001). The patients' FpA level correlated positively with malaria parasitaemia, but negatively with plasma fibrinogen concentration. A week after commencement of chloroquine therapy and subsequent disappearance of malaria parasites from the thick blood films, the patients' FpA levels decreased significantly from pre-treatment values. It is suggested that the elevated FpA and reduced plasma fibrinogen levels in the patients probably indicate a more widespread existence of overt coagulation defect in acute malaria infection.

Acute Disease↗
PubMed1994

Sexually transmitted diseases in Ibadan in the 1990's: HIV infection--an additional dimension.

Five hundred and fifty-one patients attending the Special Treatment Clinic (STC) of the University College Hospital, Ibadan, between January 1989 and July 1990 were investigated for the common sexually transmitted diseases to determine the current relative prevalence rates of these infections. The patients were also investigated for human immunodeficiency virus (HIV) infection. Of the 551 patients, 384 (69.9%) were diagnosed as having sexually transmitted diseases. The most frequent STDs were gonococcal infections, non-specific urethritis and cervicitis and the genital ulcer diseases (GUDs) with prevalence rates 25.6%, 17.8% and 12% respectively. In addition to the common STDs, HIV infection was detected in 28 (5.1%) patients. Both HIV-1 and HIV-2 were detected as follows: HIV-1 in 16 (2.9%) patients and HIV-2 in 12 (2.2%) patients. All but one of the HIV-seropositive patients also had concurrent sexually transmitted diseases.

Adolescent↗
PubMed1993

HIV seropositivity in Nigerians with lymphoproliferative malignancies.

One hundred and four Nigerians with lymphoproliferative malignancies were tested for antibodies to human immunodeficiency virus types 1 and 2 (HIV-1 and 2). All the patients with high grade lymphomas in this series were seronegative for HIV-1 and 2. Only 1 of the 104 patients had antibody to HIV-1 and none had antibody to HIV-2. Although the single positive result would suggest a higher HIV-1 seropositivity rate among the patients compared with the general Nigerian population, it should be interpreted with caution. This preliminary data emphasizes the need for an urgent countrywide study of the problem among this category of patients in Nigeria in view of the low prevalence rate of HIV-1 and 2 in the country.

Adolescent↗
PubMed1993

Haemoglobin A2 (Hb A2) and malaria.

The Packed Cell Volume (PCV), reticulocyte count and Hb A2 were determined in 28 patients during the period of malaria parasitaemia and 14 days after effective treatment. The Hb A2 was determined by cellulose acetate haemoglobin electrophoresis in alkaline medium followed by elution in water. There was no statistically significant difference between the PCV during the period of parasitaemia and that after treatment (p > 0.05). The Hb A2 level did not show any significant difference during and after treatment of malaria (p = 0.05). The correlation coefficient between absolute parasite count and Hb A2 level was -0.22 (p = 0.251). It is concluded that malaria parasitaemia does not induce a significant change in the level of Hb A2.

Adolescent↗
PubMed1992

Platelets and platelet disorders in Africa.

Blood platelets, which are known to play important roles in normal vertebrate biology, are influenced by a variety of factors, the majority of which are acquired. In this chapter, attention is drawn to the need to re-examine one of the old accepted values in haematology, the normal platelet count. In addition, effects of some environmental factors, such as malarial parasitaemia, on both platelet count and platelet function are fully discussed. Similarly, the effects of HIV on platelets, as well as on other haematological parameters, in the African environment are described briefly. The urgent need is stressed for careful evaluation of the impact of HIV on the total disease burden in the population. In addition, the effect of environmental factors on the manifestations of some clinical features, e.g. splenomegaly and anaemia, in acute idiopathic thrombocytopenic purpura are highlighted. It is suggested that in such environments, the presence of these features do not constitute contraindications to making the diagnosis when other criteria are met.

Africa↗
PubMed1990

Prognosis of acute lymphoblastic leukaemia in Ibadan, Nigeria.

Patients with acute lymphoblastic leukaemia (ALL) seen in University College Hospital, Ibadan, Nigeria, still have low rates of complete remission and relatively short survival. Yet the overall prognosis was expected to have improved because the proportions of adults, males and people of low socio-economic class among the patients have decreased steadily over the past three decades. Possible causes of the persistent poor performance were sought for in 30 new ALL patients seen in the hospital over a period of 2 years and 9 months. Unfavourable prognostic factors, lack of standard cytotoxic drugs, inadequate supportive care and absence of modern facilities for therapy combined to make their disease outcome worse than expected.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Platelet aggregation inhibition in Trypanosoma vivax infection of sheep.

We have investigated in vitro platelet aggregation in platelet rich plasma from Trypanosoma vivax infected and control sheep using the dual channel Payton Aggregometer. Final concentrations of the following inducing agents were used: 1.2 um ADP, 6.2 ug collagen, 1.2 ug ristocetin and 1 u thrombin. These showed that there was a significantly reduced aggregation of platelets from infected sheep (13.4 +/- 1.1 pc at week 3 post infection when compared with control sheep PRP 95.0 +/- 1.0pc; P less than 0.001) using ADP. Similar differences were also obtained with other inducing agents. Preliminary 14C-5HT uptake and release studies showed that there was difference in the uptake of label between platelets from infected (18.6pc) and control (28.4pc) sheep. However, when release was inducted, comparable results were obtained for both infected and control sheep platelets. It is concluded that the degree of aggregation inhibiting varies directly with the level of parasitaemia.

Animals↗
PubMed1989

Changing patterns of acute lymphoblastic leukaemia in Nigeria.

An increase in the number of Nigerian patients with acute lymphoblastic leukaemia (ALL), relative to those having acute myelogenous leukaemia, was predicted some years ago. This was expected to result from an enhanced socio-economic status of most members of the general population and improved nutrition. A review of the features of ALL patients seen in University College Hospital, Ibadan, during different periods over the past three decades revealed not only the predicted changes but also an increasing proportion of pediatric and female patients. Except for an unusual number of patients with the rare L3 morphological variant seen within the last 2 years, little else changed in the clinical and laboratory features of the disease. Atrophy of the thymus resulting from malnutrition is thought to inhibit the occurrence of common-ALL in the first decade of life. This inhibition is removed by improved nutrition, thus allowing more cases of common-ALL to develop in children. The trend in Nigeria has been observed earlier among Arabs in the Gaza Strip in the Sinai Peninsula. If the hypothesis is correct, undernutrition occurring for a long enough time in a previously well-nourished population should lead to changes opposite to those observed. The increasing percentage of patients who are either young, female or of high socio-economic class imply better prognosis for more Nigerian ALL patients.

Adolescent↗
PubMed1989

Platelet-aggregating activity of released factor(s) from Trypanosoma brucei brucei.

The effect of factors derived from Trypanosoma brucei brucei on rat platelets was studied. T. brucei at a concentration of 4 X 10(9) trypanosomes/ml phosphate saline glucose (PSG) was stored at -20 degrees C for 18 h, thawed, and a supernatant fraction, trypanosome-derived supernatant (TDS) was obtained by spinning the sample at 3000 g for 10 min at 20 degrees C. Normal rat platelets, prepared as platelet-rich plasma (PRP), were then incubated with TDS in the absence or presence of ADP (0.05-0.1 microM). The results showed that approximately 83% platelet aggregation was induced by addition of TDS (50 microliters; 113 micrograms protein) to 100 microliters PRP with a platelet count of 10(6). simultaneous addition of ADP and TDS to PRP produced a synergistic effect. It was also shown that a supernatant fraction, obtained by incubating live T. brucei (4 X 10(9)/microliters PSG) at 0 degrees C 1 h and spinning down the trypanosomes (3000 g for 10 min), also induced platelet aggregation. The nature of the factor(s) derived from, or released by, T. brucei inducing platelet aggregation is being investigated but it has been shown not to be ADP.

Animals↗
PubMed1987

Platelet reactions after interaction with cultured Plasmodium falciparum infected erythrocytes.

An in vitro model for studying the interaction between normal human platelets and Plasmodium falciparum infected erythrocytes in culture is described. After the interaction, changes in platelet function such as enhanced aggregation response to exogenous ADP and increased secretion of dense granule contents were reproduced. Some of these responses represented manifestations of platelet hypersensitivity described earlier in acute malaria infections in man and mice. Preliminary investigations of the mechanisms involved in such reactions revealed that ADP and thromboxane A2 mechanisms contributed about 79% and 18.5% of the enhanced aggregation response to exogenous stimuli in the system.

Adenosine Diphosphate↗
PubMed1987

Platelet reactions in acute Plasmodium berghei infection in Swiss albino mice.

Swiss albino mice were infected by the intraperitoneal route with P. berghei berghei malaria parasite, and platelets, white cell counts and some coagulation parameters were monitored in order to find out whether changes reported in man also occurred in the mice. Parasitaemia developed form the 2nd post-infection day and reached significant levels by the 4th-6th day. Reduced circulating platelets which reached severe thrombocytopenic levels were observed. parallel with the increasing degree of parasitaemia. Anaemia which progressed to severe degree was also observed as was a slight leucocytosis attributed to the presence of normal mouse erythrocytes in the peritoneal space. All untreated animals died by the 6th day of infection. Intramuscular chloroquine sulphate (20 micrograms/g body wt.) given for 7 days completely cured the malaria, and white cell and platelet counts were restored to preinfection levels in each animal about 2 weeks after treatment had ceased. Platelet hypersensitivity to exogenous ADP was observed within 48 hours of infection and persisted with the parasitaemia. Prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged while clottable fibrinogen concentration was reduced.

Animals↗
PubMed1986

Carrier detection in hemophilia A: a cooperative international study. I. The carrier phenotype.

Eight laboratories in six countries cooperated to clarify several issues concerning the phenotypes of heterozygous carriers of hemophilia "A." Plasma levels of factor VIII (F.VIII:C, formerly VIII:C) and von Willebrand factor (VWF:Ag, formerly VIIIR:Ag) of carriers and normal women were determined by various "in-house" methods; a single lyophilized plasma standard was used for all assays. Analysis of the collated data from 336 carriers (296 obligatory carriers and 40 sporadic carriers) and 137 normal women showed that there was no difference in the F.VIII:C levels of "paternal" carriers (women who had obtained the abnormal gene from their fathers) and "maternal" carriers. Neither was there a difference in the VWF:Ag levels of normal women and either type of carrier. Age was found to have a significant effect on both F.VIII:C and VWF:Ag, values being higher at very young and very old ages, the minima occurring in the 25- to 30-year range. ABO blood type had a striking effect. Women of types A, B, and AB (designated non-O in the study), both normals and carriers, had significantly higher levels of both factors than did women of type O. Analysis by laboratories showed that differences in mean levels of both factors between laboratories were highly significant. It was concluded that age, ABO blood type, and laboratory variation should be taken into account in carrier detection.

ABO Blood-Group System↗
PubMed1986

Carrier detection in hemophilia A: a cooperative international study. II. The efficacy of a universal discriminant.

Factor VIII (F.VIII) and von Willebrand factor (VWF):Ag data collected by eight laboratories on a total of 336 obligatory carriers of hemophilia A and 137 normal women were used to answer several questions concerning the construction of linear discriminants for carrier detection. It was found: that a "universal" linear discriminant can be constructed which is suitable for use in all laboratories and is nearly as effective as laboratory-specific discriminants; that inclusion of age and ABO blood type data improved the efficacy of these discriminants; that substitution of alternative assays for F.VIII and VWF:Ag did not generally improve the efficacy of the discriminants over that obtained using the bioassay for F.VIII:C and Laurell's immunoassay for VWF:Ag; that linear discriminants were far more effective than discriminants based on the F.VIII:C/VWF:Ag ratio. A step-wise procedure is given which any laboratory may follow in using the universal discriminant for carrier detection.

ABO Blood-Group System↗
PubMed1985

The inhibitory effects of ferriprotoporphyrin IX on platelet aggregation and release of serotonin.

Ferriprotoporphyrin IX (FP) dissolved in 0.025N NaoH in concentrations of 0.01 - 0.04 microM/ul platelet suspension competitively inhibited platelet aggregation induced by a low concentration of collagen. 14C-serotonin release was also inhibited. Higher concentrations of collagen overcame the aggregation inhibition. A similar pattern of results was obtained with thrombin-, and arachidonic acid-induced aggregation and release. With ristocetin, there was little inhibition of aggregation although serotonin release was inhibited. ADP-induced aggregation was partially inhibited except at FP concentrations of 0.91 microM/mul. FP caused only platelet shape change and serotonin release of up to 8.1%. These changes were not associated with significant platelet lysis and could also not be attributed to pH or temperature changes. There was no inhibition of collagen-induced aggregation in PRP, but FP precipitates aggregated washed platelets and caused serotonin release. These results show that FP in solution inhibited platelet aggregation induced by the different agents studied. It did not interfere with platelet agglutination induced by ristocetin. The mechanism(s) of aggregation inhibition remains to be clarified.

Adult↗