Molecular defects in the beta-globin gene identified in different ethnic groups/populations during prenatal diagnosis for beta-thalassemia: a Malaysian experience

Abstract   β-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 β-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71–72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb ^Gγ(^Aγδβ)° and 45-kb Filipino deletions. The 192 β-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 β-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of β-thalassemia. β-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese β-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay β-thalassemia carrier. The β-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of β-thalassemia in Malaysia.     

Defining epithelial cell progenitors in the human oxyntic mucosa

In the human stomach, the oxyntic epithelium includes numerous tubular invaginations consisting of short pits opening into long glands. The pit is lined by pit cells, whereas the gland is composed of three regions: the base, containing zymogenic cells; the neck, containing neck cells; and the isthmus, composed of little known immature cells and of parietal cells, which are also scattered through the neck and base. The aim of this study was to examine the ultrastructure of the immature cells and to determine their relation to mature cells. To do so, normal oxyntic mucosal biopsies from subjects ranging from 20-43 years old were fixed in aldehydes and postfixed in reduced osmium for electron microscopy and morphometric analysis. The immature cells were sorted out into four classes, whose roles were clarified by comparison with the thoroughly investigated mouse oxyntic epithelium. The first class was composed of the least differentiated immature cells, which were rare and characterized by minute, dense, or cored secretory granules and were accordingly named mini-granule cells. Their function was not clarified. The second class consisted of pre-pit cells, which were characterized by few dense mucous granules and give rise to pit cells that ascend the pit wall and, after reaching the luminal surface, die or are extruded. Both pre-pit and pit cells underwent continuous renewal and, therefore, together constituted a renewal system referred to as pit cell lineage. The third class, or pre-neck cells, characterized by cored secretory granules, give rise to neck cells that descend toward the base region and differentiate further into pre-zymogenic cells, which finally become zymogenic cells. The latter eventually degenerate and die. Thus pre-neck cells and their progeny constitute a renewing system, designated zymogenic cell lineage. The fourth class, or pre-parietal cells, characterized by long microvilli and few tubulovesicles, differentiate into parietal cells that descend along the neck and base regions and eventually degenerate and die. Pre-parietal and parietal cells represent a renewing system referred to as parietal cell lineage. While the origin of the last three classes of progenitor cells has not been elucidated, it is likely that they arise either from an unidentified multipotential stem cell, possibly the mini-granule cell itself, or from the mitotic activity of pre-pit and pre-neck cells. In conclusion, the human oxyntic epithelium is composed of continually renewing cells organized in distinct cell lineages.     

Distribution of HLA class II alleles and haplotypes in insulin-dependent moroccan diabetics

HLA class II polymorphism in Moroccan IDDM patients has not been investigated so far. In this study, HLA-DRB1, -DQA1, and -DQB1 allele and haplotype frequencies were analyzed in 125 unrelated Moroccan IDDM patients and 93 unrelated healthy controls, all originating from the Souss region and mostly of Berber origin. Some common features with other Caucasian groups were observed, in particular, a predisposing effect of the DRB1^*03-DQA1^*0501-DQB1^*0201 and DRB1^*04-DQA1^*0301-DQB1^*0302 alleles or allelic combinations. The Moroccan IDDM group also presented with more specific characteristics. Among DRB1^*04 subtypes, DRB1^*0405 was associated with susceptibility to and DRB1^*0406 with protection from the disease. The haplotype and the relative predispositional effect (RPE) analyses indicated that the DRB1^*08-DQA1^*0401DQB1 ^*0402 haplotype was also associated with susceptibility to IDDM. Interestingly, the DRB1^*09DQA1 ^*0301-DQB1^*0201 haplotype, completely absent from the control group and very rare in North African populations, was observed in 7.2% of the Moroccan diabetics. Conversely, the DRB1^*07-DQA1^*0201DQB1 ^*0201 and DRB1^*15-DQA1^*0102-DQB1^*0602 haplotypes were associated with protection from IDDM. Finally, we observed an age-dependent genetic heterogeneity of IDDM, the frequencies of predisposing alleles being higher and those of protective alleles lower in childhood- than in adult-onset diabetics. Our data on Moroccan diabetics, together with data on European and Northern Mediterranean patients, suggest a gradient of various HLA class II predisposing and protective markers that link these populations     

Environmental conditions and variation in levels of sun exposure among children in child care

Sun exposure in childhood is 1 of the risk factors for developing skin cancer, yet little is known about levels of exposure at this age. This is particularly important in countries with high levels of ultraviolet radiation (UVR) such as Australia. Among 49 children 3 to 5 years of age attending child care centers, UVR exposure was studied under 4 conditions in a repeated measures design; sunny days, cloudy days, teacher’s instruction to stay in the shade, and a health professionals instruction to apply sunscreen. Three different data collection methods were employed: (a) completion of questionnaire or diary by parents and researcher, (b) polysulphone dosimeter readings, and (c) observational audits (video recording). Results of this study indicated that more than half the children had been sunburnt (pink or red) and more than a third had experienced painful sunburn (sore or tender) in the last summer. Most wore short sleeve shirts, short skirts or shorts and cap, that do not provide optimal levels of skin protection. However, sunscreen was applied to all exposed parts before the children went out to the playground. Over the period of 1 hr (9–10 a.m.) the average amount of time children spent in full sun was 22 min. On sunny days there was more variation across children in the amount of sun exposure received. While the potential amount of UVR exposure for young children during the hour they were outside on a sunny day was 1.45 MED (Minimum Erythemal Dose), they received on average 0.35 MED, which is an insufficient amount to result in an erythemal response on fair skin even without the use of sunscreen.     

Acute hypervolemia does not improve arterial oxygenation in maximally exercising thoroughbred horses

Recently, it was reported that acute hypervolemia improves arterial oxygen tension in human athletes known to experience exercise-induced arterial hypoxemia. Since exercise-induced arterial hypoxemia is routinely observed in racehorses and is known to limit performance, we examined whether pre-exercise induction of acute hypervolemia would similarly benefit arterial oxygenation in maximally exercising thoroughbred horses. Two sets of experiments, namely, placebo [intravenous (IV) physiological saline] and acute hypervolemia (IV 7.2% NaCl, causing an 18.2% expansion of plasma volume) studies were carried out in random order on 13 healthy, exercise-trained thoroughbred horses, 7 days apart. An incremental exercise protocol leading to 120 s of galloping at 14 m s^–1 on a 3.5% uphill incline was used. Galloping at this workload elicited maximal heart rate and induced pulmonary hemorrhage in all horses in both treatments. In the placebo study, arterial oxygen tension decreased to 76.1 (2) mmHg (P<0.0001) at 30 s of maximal exertion, but further significant changes did not occur as exercise duration increased to 120 s [arterial oxygen tension 72.4 (2) mmHg]. A significant arterial hypoxemia also developed in galloping horses in the acute hypervolemia study [arterial oxygen tension at 30 and 120 s was 76.7 (1.7) and 71.9 (1.6) mmHg, respectively], but significant differences between treatments could not be demonstrated. In both treatments, a similar desaturation of arterial hemoglobin was also observed at 30 s of maximal exercise, which intensified with increasing exercise duration as hyperthermia, acidosis and hypercapnia intensified. Thus, acute expansion of plasma volume did not benefit arterial oxygenation in maximally exercising thoroughbred horses.     

Therapeutic drug levels and toxicology screen

Toxicologic analysis cannot supplant physician skills in the diagnosis and management of poisoning; however, it is a useful adjunct when properly used. Laboratory use should reflect critical consideration of clinical contribution as well as insight into institutional capability. A detailed historic review and interview of multiple sources may provide more useful and expeditious information than the blind "drug screen." Test ordering should be limited to that which directly contributes to clinical patient management.16 Similarly, test results must be interpreted in the clinical context of patient presentation. The reported units of measurement must be carefully scrutinized; and the potential for laboratory error must be appreciated. Most importantly, communication and cooperation must be maintained between the physician and laboratory personnel if the resource is to be optimally used.     

Structure-intestinal transport and structure-metabolism correlations of some potential cancerostatic pyrimidine nucleosides in isolated rat jejunum

Summary Both transport and biotransformation processes for a series of pyrimidine nucleobases, ribonucleosides, 2-deoxyribonucleosides, and acetyl and 5-substituted derivatives of the cancerostatic agent araC were studied in the isolated everted rat jejunum with a continuous perfusion technique. Metabolic alterations during penetration were assessed by HPLC. 5-Halogeno and 5-deoxy derivatives of cytosine nucleosides exhibited higher transport rates and higher stability towards the deamination reaction than did unsubstituted derivatives. Octanol-buffer partition coefficients were estimated for the study compounds, and fragmental constants for the sugar moieties of nucleosides were assessed. With the present study compounds there was no correlation between lipophilicity and transport rate, as previously reported, but there was a correlation between lipophilicity and metabolic alteration of araC derivatives (r=0.99, n=5).     

The simultaneous assay of emetine and cephaeline in ipecacuanha and its preparations by spectrofluorimetry

A rapid assay is described for the simultaneous determination of emetine and cephaeline in ipecacuanha and its preparations, based upon the different fluorescence intensities of the alkaloids at pH 1 and pH 12. The assay involves the measurement of fluorescence at 317 nm of dilutions of the sample in 0.1 M hydrochloric acid (pH 1) and 0.01 M sodium hydroxide (pH 12) with an excitation wavelength of 283 nm. Concentrations of the individual alkaloids are calculated using two simultaneous equations derived from the experimentally determined coefficients of fluorescence of solutions (1 μg/ml) of emetine and cephaeline at pH 1 and pH 12. The procedure, which has been shown to be accurate, precise and sensitive, requires only 1 ml of a liquid sample and less than 0.5 g of powdered root. There was reasonable agreement between the total concentrations of alkaloids in tinctures and liquid extracts of ipecacuanha determined by the spectrofluorimetric method and by the titrimetric procedure of the British Pharmacopoeia. The fluorimetric procedure gave higher levels of alkaloids in the powdered root than did the B.P. method; this difference is explained by incomplete extraction of the alkaloids in the B.P. procedure for powdered ipecacuanha root.     

Depression,sleeping pattern,and suicidal ideation among medical students in Bangladesh: a cross-sectional pilot study

Journal of Public Health - Depression is a major morbidity and the most common mental disorder among the medical students in medical schools globally. Undergraduate students suffer stress more due...     

Meta-Analysis and Systematic Review of Micro- and Macro-Nutrient Intakes and Trajectories of Macro-Nutrient Supply in the Eastern Mediterranean Region

The Eastern Mediterranean Region (EMR) is experiencing a nutrition transition, characterized by the emergence of overnutrition and micro-nutrient deficiencies. No previous study has comparatively examined nutrient intake in adults across countries in the EMR. This review examined the adequacy of nutrients in adults living in the EMR. Moreover, it analyzed the food balance sheets (FBS) for 1961–2018 to identify the trajectory of energy supply from macro-nutrients in the EMR. A systematic search was conducted from January 2012 to September 2020. Only observational studies were retained with a random sampling design. An assessment of the methodological quality was conducted. Levels of nutrient daily intake and their adequacy compared to the daily reference intake of the Institute of Medicine were reported across the region. No studies were identified for half of the region’s countries. Although nutrient energy intake was satisfactory overall, fat and carbohydrate intake were high. Intake of vitamin D, calcium, potassium, zinc, and magnesium were below that recommended. The analysis of the FBS data allowed for the identification of four linear patterns of trajectories, with countries in the EMR best fitting the ‘high-energy-supply from carbohydrate’ group. This systematic review warrants multi-sectorial commitment to optimize nutrient intake.