Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sickle Cell Trait”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1999

Longitudinal study of Plasmodium falciparum infection and immune responses in infants with or without the sickle cell trait.

BACKGROUND: Individuals may be homozygous (SS) or heterozygous (AS) sickle cell gene carriers or have normal adult haemoglobin (AA). Haemoglobin S could have a protective role against malaria but evidence is sparse and the operating mechanisms are poorly known. METHODS: We followed two cohorts of children. The first was enrolled at birth (156 newborn babies) and the second at 24-36 months old (84 children). Both cohorts were followed for 30 months; monthly for parasitological data and half yearly for immunological data. RESULTS: In the first cohort, 22%, and in the second 13% of children were AS. Whatever their age parasite prevalence rates were similar in AA and AS individuals. Mean parasite densities increased less rapidly with age in AS than in AA children, and were significantly lower in AS than in AA children >48 months old. The AA children tended to be more often admitted to hospital than AS children (22% versus 11%, NS). Both anti-Plasmodium falciparum and anti-Pfl55/RESA antibody rates increased more rapidly in AA than in AS children. Conversely, the prevalence rate of cellular responders to the Pfl55/RESA antigen was similar in AA and AS children during the first 2 years of life, then it was higher in AS than in AA children. CONCLUSIONS: Sickle cell trait related antimalarial protection varies with age. The role of the modifications of the specific immune response to P. falciparum in explaining the protection of AS children against malaria is discussed.

Animals↗
PubMed1982

Reversal of retinal and optic disc ischemia in a patient with sickle cell trait and glaucoma secondary to traumatic hyphema.

A 14-year-old black boy with sickle cell trait, who sustained a traumatic hyphema, developed moderately elevated intraocular pressure that failed to respond to carbonic anhydrase inhibitors and osmotic agents. On the tenth postinjury day, a sudden increased cupping of the optic disc and partial central retinal artery obstruction caused painless loss of vision. Reversal of the cupping, the retinal ischemia, and the intraocular pressure was documented following anterior chamber paracentesis, and visual acuity returned to 6/6. Pathophysiology of the posterior ischemia is discussed. This case documents the potentially debilitating course of traumatic hyphema in "benign" sickle cell trait and its avoidance with proper management. The authors endorse recent suggestions for careful observation of any sickle cell patient with traumatic hyphema, and recommend anterior chamber paracentesis, supplemental oxygen, and avoidance of osmotic agents, if secondary glaucoma develops following the initial trauma.

Adolescent↗
PubMed1986

Decreased birth weight and femur length in fetuses of patients with the sickle-cell trait.

The mean birth weight in women with the sickle-cell trait (Hb-AS) was less than in a matched population (Hb-AA), and the difference was statistically significant. Ultrasonic fetal biparietal diameter measurements in 30 patients with Hb-AS fell within normal limits, but mean femur lengths were found to be reduced at each gestational period when compared with similar measurements in patients with normal hemoglobin.

Adolescent↗
PubMed2006

Frequencies of peripheral blood myeloid cells in healthy Kenyan children with alpha+ thalassemia and the sickle cell trait.

The high frequencies of both alpha+ thalassemia and the sickle cell trait (hemoglobin AS [HbAS]) found in many tropical populations are thought to reflect selection pressure from Plasmodium falciparum malaria. For HbAS, but not for alpha+ thalassemia, protection appears to be mediated by the enhanced phagocytic clearance of ring-infected erythrocytes. We have investigated the genotype-specific distributions of peripheral blood leukocyte populations in two groups of children living on the coast of Kenya: a group of healthy P. falciparum parasite-negative children sampled at cross-sectional survey during a period of low malaria transmission, and a group of children attending the hospital with acute malaria. We report distinctive distributions of peripheral blood myeloid dendritic cells and monocytes in children with alpha+ thalassemia and HbAS during healthy periods and disease, and suggest ways in which these might relate to the mechanisms of protection afforded by these conditions.

Child↗
PubMed1991

Effects of alpha-thalassemia and sickle polymerization tendency on the urine-concentrating defect of individuals with sickle cell trait.

A defect in urine concentrating ability occurs in individuals with sickle cell trait (HbAS). This may result from intracellular polymerization of sickle hemoglobin (HbS) in erythrocytes, leading to microvascular occlusion, in the vasa recta of the renal medulla. To test the hypothesis that the severity of the concentrating defect is related to the percentage of sickle hemoglobin present in erythrocytes, urinary concentrating ability was examined after overnight water deprivation, and intranasal desmopressin acetate (dDAVP) in 27 individuals with HbAS. The HbAS individuals were separated into those who had a normal alpha-globin genotype (alpha alpha/alpha alpha), and those who were either heterozygous (-alpha/alpha alpha) or homozygous (-alpha/-alpha) for gene-deletion alpha-thalassemia, because alpha-thalassemia modulates the HbS concentration in HbAS. The urinary concentrating ability was less in the alpha alpha/alpha alpha genotype than in the -alpha/alpha alpha or -alpha/-alpha genotypes (P less than 0.05). After dDAVP, the urine osmolality was greater in patients with the -alpha/-alpha genotype than with the -alpha/alpha alpha genotype (882 +/- 37 vs. 672 +/- 38 mOsm/kg H2O) (P less than 0.05); patients with the -alpha/alpha alpha genotype had greater concentrating ability than individuals with a normal alpha-globin gene arrangement. There was an inverse linear correlation between urinary osmolality after dDAVP and the percentage HbS in all patients studied (r = -0.654; P less than 0.05). A linear correlation also existed for urine concentrating ability and the calculated polymerization tendencies for an oxygen saturation of 0.4 and O (r = -0.62 and 0.69, respectively). We conclude that the severity of hyposthenuria in HbAS is heterogeneous. It is determined by the amount of HbS polymer, that in turn is dependent upon the percentage HbS, which is itself related to the alpha-globin genotype.

Adult↗
PubMed1995

Sickle cell trait: dual picture of blood films.

The picture of the blood films of subjects with the sickle cell trait is still controversial. While some authors report the presence of sickled cells in the blood films of these subjects, others disagree. This paper submits that sickled cells could be seen in the blood films of subjects with the sickled cell trait, especially in those resident in high altitude areas.

Anemia, Sickle Cell↗
PubMed1978

Red cell survival after aortic valve replacement with Björk-Shiley prosthesis in presence of sickle-cell trait.

A case of aortic valve replacement with a Björk-Shiley disc prosthesis in a patient with sickle-cell trait is presented. Six months after operation red cell survival was not significantly reduced. On theoretical and clinical grounds it is concluded that the presence of sickle-cell trait does not contribute to late postoperative haemolysis after heart valve replacement.

Anemia, Sickle Cell↗
PubMed1982

Responses to exercise in children with sickle cell trait.

To determine whether responses to exercise in children with sickle cell trait (AS) are different from those of normal children, we performed dynamic cycle ergometer stress testing in 48 children with AS, aged 4 to 21 years. We compared these data with those obtained from 184 healthy black children. No subject with AS demonstrated definite ischemia on the exercise ECG, but four (8.3%) had equivocal ischemia. Population statistics derived from Z score values showed that the subjects with AS had lower exercise values for heart rate and work load than the controls. The BP response to exercise was normal in subjects with AS. Since no ischemia or complications occurred, exercise in subjects with AS appears to be safe. Further studies are needed to define the mechanism for the impaired pulse rate and work load variables.

Adolescent↗
PubMed1988

Cardiopulmonary and gas exchange responses to acute strenuous exercise at 1,270 meters in sickle cell trait.

The impact of strenuous exercise and environmental hypoxia on sickle cell trait (SCT) remains controversial. To determine if these factors induce cardiopulmonary and gas exchange abnormalities in SCT, healthy, young black male volunteers, 25 with SCT (HbAS) and 16 control subjects (HbAA), were evaluated during incremental and steady-state exercise tests using a cycle ergometer at 1,270 meters and 24 degrees C. Peak incremental exercise values for power (242 +/- 7 versus 253 +/- 10 watts), oxygen consumption (3.08 +/- 0.1 versus 3.26 +/- 0.14 liters/minute), heart rate (188 +/- 2 versus 189 +/- 3 beats/minute), minute ventilation (129 +/- 4.6 versus 144 +/- 7.7 liters/minute), oxygen pulse (16.4 +/- 0.5 versus 17.3 +/- 0.8 ml/beat), and respiratory exchange ratio (1.31 +/- 0.01 versus 1.33 +/- 0.02) revealed no significant differences (p less than 0.05) between the SCT and control groups, respectively. Peak incremental exercise values for arterial oxygen tension (82 +/- 1.7 versus 82 +/- 2.2 mm Hg), arterial carbon dioxide tension (32 +/- 0.7 versus 31 +/- 0.9 mm Hg), and alveolar-arterial oxygen pressure differences (19 +/- 1.4 versus 21 +/- 1.9 mm Hg) were similar for the SCT and control groups, respectively. Steady-state exercise results corroborate incremental exercise findings. It is concluded that cardiopulmonary and gas exchange responses to a brief period of strenuous exercise performed at low altitude at 24 degrees C in a well-characterized SCT sample of recruits were within normal limits and comparable to those of a carefully selected control sample.

Adult↗
PubMed1989

Haematological status of blood-donors with sickle cell trait and alpha thalassaemia in northern Nigeria.

Northern Nigeria is an endemic area for sickle haemoglobin (HbS), and it is common practice in many hospitals to accept blood for transfusion from donors with sickle cell trait (HbAS). In 212 healthy HbAS blood donors, the proportion of HbS was found to range between 24-47%. The HbS levels less than 38% were presumably due to the interaction of sickle-cell gene with the alpha + thalassaemia gene. Low HbS levels and presumed alpha + thalassaemia were associated with significant microcytosis and relatively low Hb A2 and Hb F, but differences were minimal. Carriers of sickle cell trait, with or without alpha + thalassaemia, appear to be acceptable as blood donors. Beta thalassaemia was not detected amongst 710 blood-donors.

Adolescent↗
PubMed2006

Does higher red blood cell (RBC) lactate transporter activity explain impaired RBC deformability in sickle cell trait?

Lactate and H(+) are suggested to promote the sickling process in red blood cells (RBCs) containing hemoglobin S. We demonstrated greater activity of the RBC monocarboxylate cotransporter MCT-1, lower RBC deformability and impaired hematological indices in sickle cell trait (SCT) carriers compared to control subjects, suggesting an involvement of MCT-1 in hemorheological disturbances in SCT carriers.

Adolescent↗
PubMed2003

Lactic response in sickle cell trait carriers in comparison with subjects with normal hemoglobin.

OBJECTIVE: The objective of this study was to assess lactic response (mmol/L) during incremental exercise in a specific population of men and women with sickle cell trait. SUBJECTS: Athletic men and women from the French West Indies showing no anemia and/or alpha thalassemia. METHODS: Anemia was ruled out by hemoglobin level, and alpha thalassemia was ruled out by hemoglobin S percentage with concomitant hemoglobin level and mean corpuscular volume. Comparison was made with control subjects with normal hemoglobin, matched for physical fitness, anthropometric data, and sex. All subjects performed an incremental exercise test using a cycle ergometer. Peak oxygen uptake (mL/min) was predicted from an equation at peak exercise. Heart rate (beats/min) was noted continuously, and blood samples were collected for lactic response determination every minute during the incremental exercise test and at 1, 3, and 5 minutes of recovery. RESULTS: Comparison of peak oxygen uptake and heart rate values showed no significant differences in subjects with sickle cell trait versus control subjects during the incremental exercise test. In contrast, analysis of variance revealed significantly lower lactic response time courses during the incremental exercise test and at peak exercise (p < 0.05) in the sickle cell trait group, whereas the heart rate time course was lower during recovery (p < 0.05). CONCLUSION: We conclude that the lower lactic response exhibited by subjects with sickle cell trait during incremental exercise was the result of an adaptive process in red blood cells in relation to either lower lactate production or greater lactate uptake capability than in individuals with normal hemoglobin.

Adaptation, Physiological↗
PubMed2001

Effect of sickle cell trait and B-Thalassemia minor on determinations of HbA1c by an immunoassay method.

OBJECTIVE: Glycated hemoglobin determination is being used worldwide to monitor the efficiency of blood glucose control and to plan treatment in diabetes mellitus patients. Several methods are used for measuring glycated hemoglobin, but a possible interference by hemoglobin variants is a major concern. The use of immunoassay methods with glycated hemoglobin-specific antibodies is supposed to overcome this problem. We are evaluating the effect of the most prevalent hemoglobinopathies in the region (sickle trait hemoglobin and B-Thalassemia) on the immunoassay method used in determining glycated hemoglobin. METHODS: Eighty-one whole blood sample hemolysates were tested for glycated hemoglobin using Beckman Synchron LX20 system, 37 of these normal adult hemoglobin represented 22 diabetic and 15 non-diabetic samples. Of the remaining 44 samples, 28 were from B-thalassemia minor and 16 from sickle-cell trait sickle trait hemoglobin patients, all non-diabetic. The samples were collected in ethylenediaminetetraacetic acid anticoagulant and analyzed immediately or stored at 4?C for not more than 2 days. RESULTS: Sickle trait hemoglobin had no effect on glycated hemoglobin measurement by Synchron LX20 while B-thalassemia minor blood elevated the value of glycated hemoglobin to the range of diabetic cases. CONCLUSION: Synchron LX20 glycated hemoglobin immunoassay method gave falsely high glycated hemoglobin results with B-thalassemia minor patient samples. Therefore, while interpreting the results of Synchron LX20 glycated hemoglobin, the patients history regarding hemoglobinopathies should be checked.

Diabetes Mellitus↗
PubMed1977

Unusual cause of acute abdomen. Sickle cell trait and nonhypoxic splenic infarction.

Splenic infarction under hypoxic conditions is a well-known complication of sickle cell trait (Hgb AS). However, this case illustrates that it may occur without any clinical conditions of circumstances associated with decreased Pao2. In addition, sickle cell trait should be included in the differential diagnoses of splenic infarction even if the patient is not of African ancestry.

Abdomen, Acute↗
PubMedDate not supplied

Successful newborn sickle cell trait counseling program using health department nurses.

Every year more than 50,000 infants with sickle cell trait are identified through newborn screening programs. An infant with trait provides a "genetic window" into a family that may be at risk for having a child with sickle cell disease. No national standards have been established for newborn trait follow-up and family counseling. In the United States, counseling to families having an infant with trait is usually very limited in scope and, in many cases, nonexistent. In West Tennessee, the Mid-South Sickle Cell Center (MSSCC) and the Department of Health have jointly developed an effective, practical, and affordable trait counseling program. A five-step counseling protocol, an accompanying counseling manual, a documentation checklist, and a fact sheet for parents were developed to support trait counselling. By training and using health department nurses, this program has provided counseling to a large percentage of families in which an infant tests positive for sickle cell trait.

Clinical Protocols↗
PubMed1990

Cell-mediated immune responses to Plasmodium falciparum purified soluble antigens in sickle-cell trait subjects.

To determine the possible differences in the immune response to Plasmodium falciparum between sickle-cell trait (Hb AS) and normal haemoglobin (Hb AA) individuals, we examined 35 Hb AS and 24 Hb AA subjects matched for age and microenvironment. Their age was 2-55 years and all lived in a malaria endemic area 300 km south of Khartoum. Antibodies to ring-infected erythrocyte surface antigen (Pf155/RESA) and to circumsporozoite (CS) protein (anti-NANP40) indicated equal exposure to falciparum malaria. Peripheral blood mononuclear cells (BMNCs) from 20/35 (57%) Hb AS subjects compared with 10/24 (42%) Hb AA subjects, responded to affinity-purified P. falciparum soluble antigens (SPAg). Of those responding to SPAg, 9 (26%) Hb AS subjects and only two (8%) Hb AA subjects had high responses. The mean proliferative response to SPAg of BMNCs from Hb AS individuals was significantly higher than in Hb AA individuals (P less than 0.025). Responses of BMNCs to PPD and PHA were also higher among Hb AS individuals and correlated positively with responses to SPAg. These findings support the hypotheses that the sickle-cell trait protects individuals from P. falciparum infections, at least in part, by modulating the immune response.

Adolescent↗
PubMed1998

[Phospholipid composition and content of the erythrocyte membrane in carriers of sickle cell trait].

By its frequency, but also by its morbidity and mortality, sickle cell disease is a real problem of public health in Senegal. It is an inherited disease of the red blood cell, characterized by vaso-occlusive manifestations in several organs, and chronic hemolytic anemia. Out of this work carried upon subjects presenting sickle cell trait (AS), we especially studied the membrane phospholipids. The aims of this study was to identify and to measure the major phospholipids of the red blood cell membrane (lecithin, lysolecithin, cephalin, lysocephalin and sphingomyelin). We noted a significant decrease of the lecithine rates, associated with significant accumulation of lysophosphatidyl choline implied in hemolysis disorders. We have also noted a significant increase of sphingomyelin which might be involved in the adhesive phenomena of the sickle cells. These preliminary results, allow to consider eventual new therapeutics, at least to reduce the clinical disorders of this painful disease.

Adolescent↗