New South Wales population-based birthweight percentile charts

Objective : To derive newborn percentile charts using NSW population and hospital-based data.
Methodology : Birthweight data for liveborn singleton infants were obtained from the New South Wales Midwives Data Collection (MDC) from 1990 to 1994 inclusive ( n = 422139). Data were also collected from King George V Hospital (KGV) for liveborn singleton infants less than 35 weeks of gestation for 1982-89 inclusive, and for all gestations for 1990-95 inclusive ( n = 30 610). Birthweight percentiles were derived using the MDC data separately for mates and females. Head circumference ( n = 29 090) and birth length percentiles ( n = 26 973) were derived from the KGV data.
Results : The charts derived from MDC data had generally higher percentiles than previously published charts. These represent the largest Australian population-based study published to date.
Conclusions : Periodic review of newborn growth charts is recommended because of changing ethnic and socio-economic factors.     

The presurgical management with erythrocytapheresis of a patient with a high-oxygen-affinity, unstable Hb variant (Hb Bryn Mawr)

BACKGROUND: Hemoglobin (Hb) Bryn Mawr is an unstable Hb variant resulting in congenital hemolytic anemia. This variant Hb also has an increased affinity for oxygen. The perioperative transfusion management of this disorder is described, and the first genomic analysis of this Hb variant is given. CASE REPORT: An 11-year-old boy, heterozygous for Hb Bryn Mawr, was referred for cholecystectomy. Sequence analysis of genomic DNA confirmed that the patients was heterozygous for a T–>C transition in the codon for amino acid 85, causing a substitution of serine for phenylalanine in the beta-globin chain. On the basis of whole-blood O2 dissociation studies, projected tissue O2 delivery would have been suboptimal during general anesthesia; therefore, a partial red cell exchange transfusion was performed to lower variant Hb and prevent tissue hypoxia during surgery. The red cell mass to be exchanged (50%) was determined from the calculated increase in O2 delivery capacity required to maintain an O2 extraction of 4 to 5 mL of O2 per dL of whole blood. The p50 of whole blood from the patients immediately after the exchange transfusion was 16.0 torr. At the time of surgery, the p50 was normal (25.9 torr). The patient's whole blood 2,3 DPG levels were 4.70 mmol per mL of red cells (before transfusion) (normal range=4.8 +/? 0.3 mmol/mL red cells), 4.07 mmol per mL of red cells (immediately after transfusion), and 4.55 mmol per mL of red cells (48 hours after transfusion). CONCLUSION: This patient with Hb Bryn Mawr was prepared for surgery with a partial exchange transfusion to prevent tissue hypoxia during anesthesia. Decreased 2,3 DPG levels immediately after transfusion resulted in increased O2 affinity of whole blood; however, 48 hours after exchange transfusion, a normal p50 (due to both removal of variant Hb and regeneration of 2,3, DPG) was observed. Partial exchange transfusion is useful in the preoperative management of patients with Hb variants characterized by increased O2 affinity.     

Evidence that SE is distal to LU on chromosome 19q

Analysis of a family informative for chromosome 19 loci establishes that the Lutheran blood group locus (LU) lies between the third component of human complement (C3) and the secretor loci (SE). Previously published lod scores for C3:LU are increased from 2.94 to 3.80. The linkage relationships (zeta and theta) between C3, LU, and SE are examined, and the proposed order and approximate genetic distances are determined to be: pter--C3-10.6cM-cen-7.4cM-LU-9cM-SE--qter.     

Selective usage of defined TCRBV genes in response to filarial antigens

The characterization of T cell reactivities that are prone to down- modulation by filarial parasites is central to understanding how these nematodes can survive for long periods of time within their human host and to design appropriate immunoprophylactic measures. In the present study, TCRBV gene usage was analyzed in response to filarial antigens by PCR using a panel of TCRBV gene segment family-specific oligonucleotide primers. Analysis of individuals highly responsive to Brugia malayi adult worm antigen (BmA) (n = 4) indicated that following stimulation with BmA a maximum of four TCRBV gene families were over- represented in each subject. Those were TCRBV2, 9, 19 and 23 in subject 1; TCRBV8, 9 and 16 in subject 2; TCRBV2, 8, 9 and 11 in subject 3; and TCRBV13 and 23 in subject 4. The analysis of one subject who was unresponsive to BmA before but regained responsiveness after diethylcarbamazine treatment revealed that there was no overexpression of a particular TCRBV gene family before chemotherapy, whereas after chemotherapy three TCRBV gene families (TCRBV8, 16 and 19) were found to be overexpressed. Complementarity determining region 3 size analysis of a selection of the overexpressed TCRBV genes displayed oligoclonality in some of the observed expansions. Together these observations show that limited T cell subpopulations are clonally amplified in BmA-stimulated peripheral blood mononuclear cells of filarial responder subjects, possibly driven by a restricted number of antigens.