Newborn hemoglobin

Figure 6-5. Developmental pattern of the quaternary structure of fetal and newborn hemoglobins. (Reproduced, with permission, from Ganong WF Review of Medical Physiology, 20th ed. McGraw-Flill, 2001.)...

Fetal hemoglobin Is the major hemoglobin of the red cells of the fetus and the newborn. It has the characteristic property of being resistant to denaturatlon by alkali Hb-F Is composed of two a-chalns (the same as In Hbs A and A2) and two... 

It is generally accepted that in normal subjects, most, but not necessarily all, of the bilirubin formed results from the breakdown of hemoglobin in the reticuloendothelial system. The bilirubin is then conjugated in the liver and excreted into the bile as a water-soluble pigment. The capacity of the liver to conjugate bilirubin is limited (W6), so that in cases of overproduction (e.g., hemolytic jaundice) free bilirubin will appear in the plasma. A similar result will be obtained if the ability of the liver to conjugate bilirubin is diminished (e.g., in the newborn infant). On the other hand, if the excretion of the bile is for some reason... 

Human populations that have experienced health effects from exposure to 2-nitrophenol or 4-nitrophenol have not been identified, but little research has been conducted on this subject. Based on results from animal studies, as described in Section 2.6, it is possible that individuals who consume ethanol may have slower rates of clearance of 4-nitrophenol. This subpopulation, if exposed to 4- nitrophenol, may be considered potentially susceptible. Furthermore, newborn infants utilize fetal hemoglobin, which has reduced oxygen-carrying capacity, and also have low levels of nicotinamide adenine dinucleotide diaphorase, which continuously reduces methemoglobin therefore, infants (as well as individuals congenitally deficient in this enzyme) may represent... 

Abnormal hemoglobulins can be detected by electrophoresis, as shown in Figure 7.4, which includes a pattern observed in /3+-thalassemia and one in a newborn with a-thalassemia (possibly HbH disease). It should also be mentioned that, unless there is a coexisting hemoglobin abnormality resulting from a point mutation or crossover problem, the globin chains of classic a- and /3-thalassemia are perfectly normal. It is usually the quantities of either the a or the /3 chains that are decreased. Some frameshifts have been found near the terminus of the /3 chain that lead to frameshift mutations in certain areas. 

An infant has 96% hemoglobin F and 4% hemoglobin S at birth. What are the possible diagnoses What tests can be done to confirm the newborn screening test ... 

A third embryonic hemoglobin, termed Hb-Portland 1, has recently been described (Cl, C2, H6, T8, W17). The protein was first discovered in a malformed newborn with a complex autosomal chromosomal mosaicism. However, it is probably also present for some 0.5 to 5% in newborn infants with a D, trisomy and in very small amounts (0.1-0.2%) in normal newborns. Hb-Portland 1 does not contain a chains but is composed of one pair of y chains and one pair of chains which have been termed C chains. The C chain is probably a normal embryonic hemoglobin chain. Hb-Portland 1 does react with free a chains to form Hb-F or aayz and a aafa component (T8). It seems, therefore, that the chain can combine with the a chain, but the afiSnity of the a chain for the C chain is apparently lower than for either the e chain or y chain. Embryonic hemoglobins have also been found in several mammalian species, such as the pig, cattle, and sheep (K13, K15). 

Fig. 13. Starch gel electrophoresis of hemoglobin of cord blood samples from newborns with various types of a-thalassemia. Tris-EDTA-boric acid buffer, pH 8.6. Stained with o-dianisidine. From Pootrakul et al. (P22) with permission of the authors and publisher.

Fig. 15. Horizontal starch gel electrophoresis to show the small differences in mobility between three fetal hemoglobin variants. Left to right (1) Hb-F-Malta-I heterozygote, (2) and (3) normal adults (4) Hb-Fx in a Negro newborn (5) Hb-F-Malta-II heterozygote (6), (7), and (8), Hb-A, Hb-F, and Hb-F-Malta-II fractions, respectively, isolated by column chromatography on CM-cellulose. Tris-EDTA-boric acid buffer, pH 9.0, o-dianisidine stain.

The Hb-F which constitutes about 75% of the total hemoglobin in cord blood samples of full-term newborns (see references in 03) is... 

Cholestatic liver disease may occur in infancy. One particularly severe symptom is the inability to walk. The neurological symptoms can be treated with weekly injectiorrs of 100 mg a-tocopherol over half a year. Vitamin E deficiency in newborns has been associated with hemolytic anemia. Anemia is a decreased eoncen-trahon of red blood cells in whole blood as well as a drop in the hemoglobin level... 

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