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PubMed2006

Prognostic significance of monocytosis in patients with myeloproliferative disorders.

Based on clinical and pathological findings, chronic myelomonocytic leukemia (CMML) differs from other myeloproliferative/myelodysplastic disorders by its hallmark, monocytosis. It is unknown whether the presence of monocytosis and the diagnosis of CMML carry a prognostic significance. The present study aimed to determine whether the survival of patients with CMML differs from that of patients with BCR/ABL-negative CML or Ph(1-), BCR/ABL-unknown CML, once other potentially prognostic variables have been accounted for. The records of 485 patients with myeloproliferative/myelodysplastic disorders [CMML, n = 304; BCR/ABL-negative CML, n = 107; Ph(1-), BCR/ABL unknown, n = 74] were analysed. Of the covariates found to be significantly (P < 0.01) associated with survival in univariate and multivariate analyses, the following remained predictive and adversely associated with survival, after accounting for the influence of other covariates: increasing age, white blood cell count, platelets, bone marrow blasts and cellularity, decreasing hemoglobin, abnormal karyotype, and diagnosis of CMML. The diagnosis of CMML is prognostically significant and independently associated with a shorter survival and a higher risk of death than BCR/ABL-negative CML or Ph(1-) BCR/ABL-unknown CML.

Adolescent↗
PubMed2004

A novel alpha-thalassemia nonsense mutation in codon 23 of the alpha2-globin gene (GAG-->TAG) in a Tunisian family.

Herein we describe a novel alpha-thalassemia (thal) point mutation in the alpha2-globin gene, found in a 3-year-old Tunisian girl who had Hb Bart's (gamma4) at birth, later on presenting with moderate anemia, microcytosis and hypochromia. She had a normal Hb A2 level and no abnormal hemoglobin (Hb) fraction. After excluding most of the common Mediterranean mutations, the alpha2-globin gene was sequenced and found to have a point mutation in the heterozygous state that creates a premature stop signal for translation (GAG-->TAG or Glu-->Term) at codon 23. The same mutation was also found in the mother in the heterozygous state, while the father had a normal sequence. The presence of the mutation was also confirmed by nucleotide sequencing of the opposite strand. Since the mutation creates a restriction site for the BfaI enzyme, a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based assay was established for screening purposes.

Adult↗
PubMed2004

The 'hot-spot' of Hb E [beta26(B8)Glu-->Lys] in Southeast Asia: beta-globin anomalies in the Lao Theung population of southern Laos.

Hb E [beta26(B8)Glu-->Lys], is the most common abnormal hemoglobin (Hb) in Southeast Asian populations. The hitherto highest frequencies of the Hb E gene (HBB*E) in large population samples, approximately 0.3, were observed in the southern part of northeastern Thailand. The finding of even higher frequencies in a small, isolated Austroasiatic group in Northeast Thailand prompted us to examine samples of three Austroasiatic populations in southern Laos (official designation: Lao Theung), an area inhabited by numerous ethnic groups belonging to the Mon-Khmer branch. Blood samples were collected from a total of 603 adult subjects. The HBB*E frequencies were 0.426 in the So of Khammuan Province, 0.433 in the Alak/Ngeh of Sekong Province and 0.253 in the Oy of Attapeu Province. The HBB*E frequencies in the So and Alak/Ngeh are the highest observed in Southeast Asia in representative population samples. None of the common Southeast Asian beta-thalassemia (thal) mutations were found. The results are discussed with respect to natural selection by malaria, selection time, effects of beta-thal and the ethnic history of the population of Southeast Asia.

Ethnicity↗
PubMed1994

Multiple factors as mediators of the reduced incidence of low birth weight in an urban clinic population.

A five year prospective observational study was initiated in 1985 at Howard University to describe the nutritional, clinical, dietary, lifestyle, environmental, and socioeconomic characteristics of women who enrolled in the hospital prenatal clinic. The participants were nulliparous, between the ages of 18 and 35 years, free of diabetes and abnormal hemoglobins (sickle cell disease, thalassemia, and hemoglobin C), and had been admitted prior to the 29th week of gestation. During the three year period from 1985-1988, the incidence of low birth weight (LBW) in 239 deliveries to project participants was 8.3%, whereas that of women simultaneously enrolled in the prenatal clinic with the same eligibility requirements, but not recruited for the research project, was 21.9% (P = 0.001). The incidence of LBW in infants of African American women with these eligibility requirements who were delivered by private physicians but were not enrolled in the project, was 6.3%. The reduction in LBW of infants delivered to participants in this study is attributed to the enhanced social and psychological support by project staff during their pregnancies. The caring, sensitive demeanor of the research project staff may have empowered the participants to (a) give greater compliance (91 vs. 70%) in the ingestion of the routine physician-prescribed vitamin/mineral supplement, which provided nutrients low (less than 70% of the 1989 RDAs) in their customary diets, such as folate, pyridoxine, iron, zinc, and magnesium and (b) show greater accountability in keeping prenatal clinic appointments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Dietary intakes, anthropometric measurements and pregnancy outcomes.

The relationships of maternal prenatal dietary intakes and anthropometric measurements to pregnancy outcomes were investigated in a prospective observational study of urban African American women. The 322 subjects, a subset of the 744 women recruited for the study using purposive sampling, were all nulliparous, free of diabetes mellitus and abnormal hemoglobins, and delivered term, singleton infants. Sociodemographic data and monthly quantitative 24-hour food recalls were collected by trained interviewers. Maternal anthropometric measurements were obtained from the subjects' hospital records. Pregnancy outcome data were obtained by physical examinations of the newborn infants by the project pediatrician. With the exception of vitamin C, average maternal dietary intakes were within the ranges of intakes obtained in previous studies. Mean intakes of protein, vitamins A and C, thiamin, riboflavin, and niacin exceeded the 1989 RDA, while those of food energy, vitamin B-6, folate, calcium, iron, magnesium, and zinc were below the RDA. Underweight prior to pregnancy and low pregnancy weight gains were found among 12.9% and 44.4% of the subjects respectively. Dietary intakes were not significantly correlated with pregnancy outcomes. Maternal anthropometric measurements significantly correlated with pregnancy outcomes included delivery weight, pregnancy weight gain, weekly weight gain, prepregnancy weight, net weight gain, height, prepregnancy body mass index, and % ideal prepregnancy body weight (P < 0.05). Using the stepwise selection procedure in multiple regression analysis, delivery weight, % ideal prepregnancy body weight, and prepregnancy body mass index were selected as being predictive of infant birth weight. It was concluded that anthropometric measurements were better nutritional predictors of pregnancy outcome than dietary intake.

Adolescent↗
PubMed1994

Selected lifestyle practices in urban African American women--relationships to pregnancy outcome, dietary intakes and anthropometric measurements.

The relationships of selected lifestyle factors (cigarette smoking, consumption of alcoholic beverages, recreational drug use, and exercise during pregnancy), all self-reported, to pregnancy outcomes, dietary intake during pregnancy, and maternal anthropometric measurements, were investigated in a group of urban African American pregnant women. The 234 subjects were aged 16-35 years and were free of diabetes and abnormal hemoglobins. The lifestyle data were collected by trained interviewers during the subjects' prenatal clinic visits, and the dietary data by monthly, quantitative 24-hour food recalls conducted during these same visits. Maternal anthropometric measurements were obtained from the subjects' hospital records, and pregnancy outcome data during physical examinations of the newborn infants. Both cigarette smoking and drug use were associated with significantly lower mean birth weight, length, and head circumference, while exercise was associated with a significantly higher mean birth weight, and head circumference (P < 0.05). Drug use during pregnancy was associated with a significantly higher intake of vitamin C, and a significantly lower intake of iron; while women reporting drug use before pregnancy had significantly higher mean intakes of food energy, protein, total and saturated fat, and zinc. Prepregnancy weight, percent ideal prepregnancy body weight, prepregnancy body mass index, and delivery weight were significantly lower among those reporting drug use before pregnancy. Multiple regression analyses indicated that smoking explained a relatively small proportion of the variance in infant birth weight compared with delivery weight and percent of ideal prepregnancy body weight.

Adolescent↗
PubMed2001

Inhaled nitric oxide improves survival rates during hypoxia in a sickle cell (SAD) mouse model.

BACKGROUND: The hallmark of sickle cell disease (SCD) is erythrocyte sickling during deoxygenation of the abnormal hemoglobin S (HbS). When HbS is deoxygenated, it aggregates into polymers, resulting in distortion of the erythrocyte structure, producing microvascular thrombosis and ischemia. The transgenic SAD mouse produces three types of human hemoglobin: S, Antilles, and D-Punjab (HbSAD) and provides an animal model for SCD. We studied the effects of nitric oxide (NO) breathing at various doses and time regimens in the presence of severe hypoxia (6% oxygen) using the SAD mouse model. METHODS: Age- and sex-matched control and SAD mice were exposed to 6% oxygen breathing in an environmental chamber and assessed for survival up to 1 h. Animals received different inhaled NO concentrations before and/or during hypoxia. Blood was obtained to evaluate the oxyhemoglobin dissociation curve and measure methemoglobinemia. RESULTS: Pretreatment by breathing NO at 20 ppm by volume in air for 30 min, and continuing to breathe 20 ppm NO during hypoxia resulted in improvement in survival rates in the SAD mouse (75%, n = 8) as compared with control SAD mice (11%, n = 9; P < 0.001). Pretreatment alone or breathing lower doses of NO were not protective. Changes in HbSAD oxygen affinity were not detected with NO breathing, and methemoglobin levels were low in all surviving mice. CONCLUSIONS: Breathing NO produced a rapid, protective effect to severe hypoxic stress in SAD mice. There appears to be a required loading period between NO breathing and its beneficial effect during hypoxic stress, possibly because of the total amount of NO delivered to SAD hemoglobin, blood cell components, and endothelium. NO breathing may be beneficial as a therapeutic intervention in SCD.

Administration, Inhalation↗
PubMed1979

Automated method for determination of oxygen equilibrium curves of red cell suspensions under controlled buffer conditions and its clinical applications.

The accurate determination of the oxygen equilibrium curve (OEC) of whole blood or red cell suspensions requires special considerations to avoid the secondary effects due to lactate formation, removal of carbon dioxide, use of anticoagulants, etc. An automated apparatus has been constructed that can record the whole OEC of red cells within 20 min. The instrument also can be used to record the OEC of hemolysate. The pH, temperature, and PO2 are monitored constantly during the measurement. Using this instrument, the effects of pH, temperature, carbon dioxide, anticoagulants, and buffers on the OEC of normal fresh blood have been investigated. The OEC of normal blood, blood containing abnormal hemoglobin, or enzyme, were determined. The results were compared with those obtained using commercial OEC apparatuses.

Autoanalysis↗
PubMed1992

Treatment of acute myocardial infarction: a cardiologist's perspective.

The treatment of acute myocardial infarction can generally be organized along three pathways. First, interventions directed toward alleviating acute myocardial ischemia include oxygen, sublingual nitroglycerin, morphine, aspirin, heparin, and intravenous nitroglycerin. Appropriate patients may also benefit from beta-adrenergic blockers, thrombolytic agents, intra-aortic balloon counterpulsation, and revascularization with either coronary angioplasty or bypass graft surgery. Second, interventions directed toward assessing and treating acute left ventricular dysfunction include invasive hemodynamic monitoring and echocardiography; maximizing preload; correcting blood gas, serum electrolyte, acid-base, or hemoglobin abnormalities; controlling heart rate; and maintaining AV conduction. Pharmacological agents to consider include diuretics, nitroglycerin, nitroprusside, dobutamine, dopamine, norepinephrine, and amrinone. Support devices, coronary angioplasty, and cardiac surgery are also occasionally needed. Third, interventions directed toward preventing or treating arrhythmias and conduction disturbances include atropine, isoproterenol, beta-blockers, verapamil, digitalis, adenosine, lidocaine, procainamide, bretylium, amiodarone, countershock, and cardiac pacing. All of the above information has been drawn from studies in nonsurgical patients. Unfortunately, there is little in the cardiology literature about treatment of patients with perioperative MI [17]. It is of interest to note that most perioperative MI occurs in the postsurgical period, not intraoperatively, and is often painless. As discussed throughout this volume, controlling postoperative stresses--including surgical complications, pulmonary complications, fluid and electrolyte abnormalities, and heart rate and blood pressure responses--is probably important. Serial cardiac enzymes and electrocardiograms improve the diagnostic yield. Treatment options are limited by the fact that many events are non-Q wave infarctions. Also, the increased risk of bleeding from the operative site precludes use of antiplatelet, anticoagulation, and thrombolytic agents. Hemodynamically or electrically unstable patients should be referred for emergency cardiac catheterization and probable coronary angioplasty. Patients at risk for large Q wave MI, heralded by ST-segment elevation in several electrocardiographic leads, should also be considered for invasive treatment. Further clinical investigation of the natural history, diagnosis, and treatment of perioperative MI is sorely needed.

Angioplasty, Balloon↗
PubMed1988

Enzymatic diagnosis in non-spherocytic hemolytic anemia.

Blood samples from 722 unrelated patients with anemia and/or reticulocytosis were submitted to our laboratory for red cell enzyme assay during the past 7 years. Among these 722 cases, we found 82 cases of 7 different red cell enzyme deficiencies and 2 of unstable hemoglobin. Abnormalities of pyruvate kinase (PK) were found to cause hemolysis in 55 patients. Although their average PK activity was about 35% of the normal level, 5 showed normal and 2 demonstrated high PK activity. Among 17 patients in whom pyruvate kinase assays or screening tests had been carried out in routine laboratories, the correct diagnoses had been made in only 4. Glucose-6-phosphate dehydrogenase (G6PD) deficiency was found in 15 patients, pyrimidine 5'-nucleotidase deficiency in 5, glucose phosphate isomerase deficiency in 3, adenylate kinase deficiency in 2, phosphoglycerate kinase deficiency in 1, and glutathione synthetase deficiency in 1 patient. Even after we performed a panel of over 20 different red cell enzyme assays, 519 patients still remained undiagnosed.

Adolescent↗
PubMed1983

Historical review of legislative and national initiatives for sickle cell disease.

The genes responsible for the transmission of sickle cell syndromes from one generation to the next were introduced into the new world during the 17th century. However, this disease was not recorded in the medical literature in the United States until 1910 by Herrick of Chicago. During the next 40 years, many additional cases were reported and a fairly large bibliography developed which dealt essentially with descriptive, clinical and pathological aspects of the disease. New interest in the syndrome occurred in 1949 when Pauling and his associates, employing chemical and electrophoretic techniques, showed that an abnormal hemoglobin was responsible for the sickling phenomenon. In the same year, Neel and Beet, working independently of each other, clarified the inheritance of the disease on the basis of the heterozygous-homozygous hypothesis. In 1958, Ingraham combined the techniques of electrophoresis, chromatography, and trypsin digestion ("fingerprinting") to show that the difference between hemoglobins A, C, and S was in the amino acid sequence of the polypeptide chains which make up the hemoglobin molecule. However, despite these notable advances, interest in the disease remained at a relatively low scientific and health care priority until February 1971, when President Nixon in his message to Congress indicated that greater attention and support for sickle cell disease should be made available at the national level. This paper will review some of the important legislative, political, and organizational initiatives which have had a significant impact on the development and implementation of the current national sickle cell disease program in the United States.

Anemia, Sickle Cell↗
PubMed1975

Observations on the effect of CO2 and temperature on the sickling phenomenon.

The explanation of the effect of CO2 on the sickling phenomenon has, in the past, been based solely on the alteration of the oxygen affinity of haemoglobin induced by the CO2, and hence solely on the oxygen saturation of the haemoglobin. A re-investigation of this phenomenon, reported here, shows that this explanation is inadequate; rather, a full explanation requires the use of Perutz's hypothesis that the haemoglobin molecule can exist in various conformationally distinct states, the relative concentrations of which are dependent not only on the oxygen saturation of the molecules but also on other factors such as pH and 2,3-diphosphoglycerate (DPG) concentration. The effect of temperature on the sickling phenomenon is explained in a similar fashion. Low temperature is found to have no effect on the morphology of irreversibly sickled cells.

Anemia, Sickle Cell↗
PubMed1980

Clinical, hematological and genetic features of sickle-cell anemia and sickle cell-beta thalassemia in a Brazilian population.

Clinical, hematological and genetic studies were carried out on 40 patients with symptomatic sickle-cell disease, selected on the basis of a predominant HbS fraction and absence of other abnormal hemoglobin variants. Family studies showed they included 26 homozygotes for the sickle-cell gene (SS) and 14 double heterozygotes for both the sickle-cell and the (0)beta-thalassemia genes ((S)(0)beta-thalassemia). Comparison of the two groups revealed the more common occurrence of splenomegaly, lower MCV and mCH, and higher HbA2 in (S)(0)beta-thalassemia. Total hemoglobin was slightly lower in SS disease but the difference was not significant. Fetal hemoglobin (HbF) was moderately elevated to similar levels in both groups. These results suggest a high incidence of S beta (0)-thalassemia in certain Brazilian mixed populations and confirm the severity of the double heterozygous state. The distinction between the two disorders is often difficult, but can be made on the basis of the hematological data taken together with family studies.

Adolescent↗
PubMed2001

Correction of sickle cell disease in transgenic mouse models by gene therapy.

Sickle cell disease (SCD) is caused by a single point mutation in the human betaA globin gene that results in the formation of an abnormal hemoglobin [HbS (alpha2betaS2)]. We designed a betaA globin gene variant that prevents HbS polymerization and introduced it into a lentiviral vector we optimized for transfer to hematopoietic stem cells and gene expression in the adult red blood cell lineage. Long-term expression (up to 10 months) was achieved, without preselection, in all transplanted mice with erythroid-specific accumulation of the antisickling protein in up to 52% of total hemoglobin and 99% of circulating red blood cells. In two mouse SCD models, Berkeley and SAD, inhibition of red blood cell dehydration and sickling was achieved with correction of hematological parameters, splenomegaly, and prevention of the characteristic urine concentration defect.

Anemia, Sickle Cell↗
PubMed1983

The role of cell-mediated immune responses in resistance to malaria, with special reference to oxidant stress.

Asexual blood forms of malaria parasites are microaerophilic and sensitive to oxidant stress. Plasmodium falciparum and some other species of malaria parasites undergo schizogony attached to endothelial cells of postcapillary venules, where oxygen tensions are low. Acquired immune responses to all forms of malaria parasites so far investigated are thymus dependent. Animals deprived of T lymphocytes do not recover from the infections and cannot be immunized against malaria parasites. In contrast, animals unable to make antibodies recover normally from some primary infections, e.g. with Plasmodium chabaudi, and when rescued by chemotherapy from other species of malaria parasite develop lasting, nonsterile immunity. Immunity to malaria can be transferred in mice by T lymphocytes of the Ly1+ phenotype, but transfer of B lymphocytes together with this T-cell subset increases the effectiveness of immunity to Plasmodium yoelii. Thus, antibodies facilitate recovery from some primary malaria infections and increase the effectiveness of cell-mediated immune responses in these infections. Mice of the A strain are highly susceptible to malaria and are unable to increase the number of mononuclear cells in the spleen during the course of the infections. It is postulated that T lymphocytes responding to parasite antigens release factors that stimulate the proliferation of effector cell precursors and their recruitment into the red pulp of the spleen. In this site, the liver and probably the peripheral circulation, effector cells bind to the surface of parasitized erythrocytes and are activated to release superoxide (O2-). The consequent exposure to oxidant stress can lead to degeneration of parasites in erythrocytes. This effect on the parasites can be prevented by agents chelating metals, which suggests that iron-catalyzed lipid peroxidation and consequent K+ loss, or inactivation of metal-containing enzymes, may be the mechanism by which oxidant stress kills the intracellular parasites. Antibodies on the surface of schizont-infected cells could facilitate binding of effector cells and trigger O2- release, thereby acting synergistically with cell-mediated immunity. Inherited traits, such as abnormal hemoglobins and G-6-PD deficiency, and acquired cell-mediated immunity both subject malaria parasites to oxidant stress and may reinforce one another, increasing the chances of survival of children bearing these traits during the dangerous years of first exposure to malaria in areas where the disease is endemic.

Animals↗
PubMed2005

Molecular heterogeneity of beta-thalassemia in the United Arab Emirates.

The beta-thalassemia alleles in 313 national patients of the United Arab Emirates (UAE) have been characterized using PCR-based DNA-diagnostic techniques including DNA sequencing. A total of 212 patients had homozygous beta-thalassemia and the remaining 101 were compound heterozygotes. More than half of the patients were homozygous for the IVS-I-5 (G-->C) mutation followed by the sickle cell gene. The latter accounted for 25% of the chromosomes. In terms of frequency, five beta-thalassemia mutations; IVS-I-5 (G-->C), betaS, -25 bp del, Cd 8/9 (+G) and IVS-II-1 (G-->A) accounted for 83% of the alleles. In addition, 427 expatriate patients were studied: 256 with homozygous beta-thalassemia and 171 were compound heterozygotes. In both the UAE nationals and expatriates, the beta-thalassemia mutations and their frequency followed a similar trend. Our results indicate that the frequency of beta-globin gene defects including beta-thalassemia, sickle cell gene (betaS) and abnormal hemoglobins is significantly increased and poses a major public health problem in the UAE. The number of homozygous patients strongly suggests a high degree of consanguinity among the UAE nationals. With 50 different beta-thalassemia alleles, UAE is arguably the most heterogeneous population in the world. The diversity of these mutations reflects the historical admixture of genes and their migration from different areas in the region. Our data strongly suggest the need for a comprehensive thalassemia control program and provides a basis for population screening, genetic counseling and prenatal diagnosis.

DNA Mutational Analysis↗