Diagnostic utility of zinc protoporphyrin to detect iron deficiency in Kenyan pregnant women

Background

Iron-deficient erythropoiesis results in excess formation of zinc protoporphyrin (ZPP), which can be measured instantly and at low assay cost using portable haematofluorometers. ZPP is used as a screening marker of iron deficiency in individual pregnant women and children, but also to assess population iron status in combination with haemoglobin concentration. We examined associations between ZPP and disorders that are common in Africa. In addition, we assessed the diagnostic utility of ZPP (measured in whole blood and erythrocytes), alone or in combination with haemoglobin concentration, in detecting iron deficiency (plasma ferritin concentration <15 μg/L).

Methods

Single blood samples were collected from a population sample of 470 rural Kenyan women with singleton pregnancies, gestational age 13 to 23 weeks, and haemoglobin concentration ≥90 g/L. We used linear regression analysis to assess associations between ZPP and iron markers (including anaemia), factors known or suspected to be associated with iron status, inflammation markers (plasma concentrations of C-reactive protein and α ₁-acid glycoprotein), infections (Plasmodium infection, HIV infection), and other disorders (α ⁺-thalassaemia, plasma concentrations of total bilirubin, and lactate dehydrogenase). Subsequently, in those without inflammation, Plasmodium infection, or HIV infection, we used logistic discriminant analysis and examined receiver operating characteristics curves with corresponding area-under-the-curve to assess diagnostic performance of ZPP, alone and in combination with haemoglobin concentration.

Results

Individually, whole blood ZPP, erythrocyte ZPP, and erythrocyte protoporphyrin had limited ability to discriminate between women with and without iron deficiency. Combining each of these markers with haemoglobin concentration had no additional diagnostic value. Conventional cut off points for whole blood ZPP (>70 μmol/mol haem) resulted in gross overestimates of the prevalence of iron deficiency.

Conclusions

Erythrocyte ZPP has limited value to rule out iron deficiency when used for screening in conditions with a low prevalence (e.g., 10%). ZPP is of unreliable diagnostic utility when discriminating between pregnant women with and without iron deficiency. Based on these findings, guidelines on the use of ZPP to assess iron status in individuals or populations of pregnant women need review.

Trial registration

NCT01308112 (2 March 2011).

     

Infection of Laboratory-Colonized Anopheles darlingi Mosquitoes by Plasmodium vivax

Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector–pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi–Plasmodium interactions.     

Colony forming T lymphocyte deficit in the development of feline retrovirus induced immunodeficiency syndrome

The identification and molecular cloning of a feline leukemia virus (FeLV) isolate (FeLV-FAIDS) that consistently produces immunodeficiency syndrome has allowed prospective investigation of events that occur in the prodromal phase of disease. Using a T-lymphocyte colony forming assay (T-CFU-Ic) we have demonstrated that a drastic depletion of circulating T-CFU-Ic prefigures the development of clinical immunodeficiency disease in inoculated cats and correlates with the appearance and replication of the FeLV-FAIDS variant genome in serially collected bone marrow samples. During the same presymptomatic time period, no significant alterations in conventional mitogen-induced lymphocyte blastogenic responses or in circulating lymphocyte numbers were evident. Thus T-CFU-Ic assay but not conventional mitogen-driven blastogenesis identified animals destined to develop immunodeficiency syndrome. The correlation among T-CFU-Ic depletion, the replication of the lymphocytopathic FeLV-FAIDS variant genome in hematopoietic and lymphoid tissues, and the onset of clinical disease, infers that ablation of a colony-forming T lymphocyte progenitor subset is important in the early pathogenesis of feline retrovirus-induced immunodeficiency syndrome.     

Proliferation and maturation of human erythroid progenitors in liquid culture

Hemopoiesis is studied in vitro mainly in semisolid culture, where hemopoietic progenitors develop into discrete colonies. We describe a liquid culture system that supports the proliferation and maturation of human erythroid progenitors. We seeded mononuclear cells from the peripheral blood (PB) of patients with beta-thalassemia in liquid medium in the presence of conditioned medium from human bladder carcinoma cells. Seven days later, RBCs, normoblasts, granulocytes, and monocytes disappeared, and the number of lymphocytes dropped considerably. In contrast, erythroid colony-forming cells increased fourfold to tenfold. The next step entailed the removal of colony- stimulating factor (CSF) and CSF-secreting cells, the exclusion of macrophages by harvesting nonadherent cells, and the lysis of T lymphocytes by treatment with monoclonal rat antihuman lymphocyte antibodies (CAMPATH-1) and complement. Reculture of the remaining cells in liquid medium supplemented with recombinant erythropoietin (EPO) resulted in the exclusive development of erythroid cells, with myeloid cells reduced to less than 2%. Stainable hemoglobin (Hb) appeared on day 3, with over 85% of the population containing hemoglobin by day 11 and the cell number increasing from 0.2 X 10(6) to 3 X 10(6) mL. By permitting the manipulation of culture conditions and components and increasing the cell yield, the liquid system may facilitate quantitative analysis of growth kinetics as well as biochemical and immunologic characterization of the developing erythroid cell.     

Microsatellite instability and p53 mutations in therapy-related leukemia suggest mutator phenotype

During the last decade the frequency of therapy-related acute leukemia (t-leuk) and myelodysplastic syndrome (t-MDS) has been increasingly observed. Over the past 15 years, we treated 56 patients with t-leuk who had received prior chemotherapy (39%), radiotherapy (11%), or both (45%). The drugs received included alkylating agents and topoisomerase II inhibitors. The primary tumors included hematological malignancies (49%) and solid tumors such as breast or ovarian cancer. The median age at diagnosis of the primary tumor was relatively young (43 years +/- 18). Twelve patients had more than one primary tumor and 31 patients had a family history of malignancy. Karyotypic abnormalities were found in 91% of the patients. Prognosis was uniformly poor, with an overall median survival of 10 months. Twelve of the 18 patients examined (67%) had a multidrug resistance phenotype. P53 genes of the leukemic cells, as well as the original tumors, were analyzed in 21 patients using polymerase chain reaction (PCR) with single-stranded conformation polymorphism analysis followed by sequencing. P53 mutations were identified in 38% of these patients, a relatively high prevalence compared with other forms of MDS or de novo acute myeloid leukemia. Mutations were nongermline and restricted to the leukemic cells. We identified different p53 mutations in the various primary tumors of individual patients. The presence of a mutator phenotype was assessed by PCR analysis of microsatellites in eight loci (one trinucleotide repeat sequence, four dinucleotide, and three mononuclear repeat sequences). Microsatellite instability in two to seven loci were found in 15 of 16 (94%) of the patients. This instability is compatible with a mutator phenotype, which predisposes the patients to the development of malignancies including t-leuk.     

成像检查对腰背痛治疗临床决策的影响

目的 :评价断面成像 ,如磁共振成像 (ＭＲＩ)、计算机体层成像 (ＣＴ)对腰背痛 (ＬＢＰ)患者的临床决策的影响。方法 :对 14 5例有症状的腰椎疾病且曾就诊过神经外科或骨科医生的患者进行前后随机对照研究。参与者是腰背痛 (ＬＢＰ)治疗中两种成像检查的多中心实用随机比较的亚群 :即“成像”对“未成像” ,除非出现明确的指征。配对的评价是由诊断、诊断可信度、后续治疗、试验开始和随访的治疗可信度以及预期的成像所组成。数据通过随机组分析得到。结果 :在随访中有关诊断和治疗方案组之间并无统计学显著差异。但在两组中诊断和治疗可信…