Association of normal levels of both haemoglobin and white blood cells count with normality of complete blood count.

Objective: To assess the use of haemoglobin and white blood cell count together in predicting the normality of other complete blood count parameters and blood film. METHODS: The prospective study was conducted from August to November 2021 at Al-Yarmouk Teaching Hospital, Baghdad, Iraq, and comprised adult individuals of either gender who were advised blood test by physicians in the outpatient department. Patients with normal haemoglobin and white blood cell counts were placed in group A, while those with abnormal counts of the two parameters were placed in group B. Examination of blood smears morphology was done in both groups. Data was analysed using SPSS 26. RESULTS: Of the 200 subjects, 100(50%) were in group A; 58(58%) males and 42(42%) females with mean age 51.09±18.8 years. There were 100(50%) subjects in group B; 52(52%) males and 48(48%) females with mean age 47.58±15.5 years (p>0.05). In group A, 70(70%) cases showed normal complete blood count parameters and abnormal morphology of 1+ grading in 13(13%). The results were significantly different than group B (p<0.05). CONCLUSIONS: Normal haemoglobin and white blood cell count was found to a good marker for the normality of other complete blood count parameters.

The effect of dates and honey extracts (phoenix dactylifera and apis mellifera) for increasing pregnant women's haemoglobin.

Objectives: To examine the effect of date fruit extract and honey in increasing haemoglobin levels in pregnant women. METHODS: The quasi-experimental study was conducted from July to August 2022 in Rumbai Pesisir Subdistric, Pekanbaru, Indonesia, and comprised anaemic pregnant women with haemoglobin levels <11gm/dl who were not consuming iron tablets or blood boosters. They were given honey and date extracts 2 tablespoons twice daily for two weeks. Haemoglobin level was checked at baseline and then at the end of each week of intervention. Data was analysed using SPSS version 20 and quantitative method by using bivariate analysis. RESULTS: Of the 50 women, 59(98%) were aged 20-35 years, and 1(2%) was aged >35 years. Besides, 21(42%) women were in the second trimester, 17(34%) in third, and 12(24%) in the first trimester of pregnancy. The increase in haemoglobin levels post-intervention was highly significant (p=0.0001). CONCLUSIONS: Date fruit extract and honey increased haemoglobin level of pregnant women.

Anaemia prevalence and risk factors among children aged 6 to 23 months in rural China.

INTRODUCTION: Anaemia is a global public health problem among children. However, few studies have examined anaemia prevalence and risk factors among Chinese children of different ages, particularly in poor rural areas. This study investigated these two aspects among children aged 6 to 23 months in poor rural areas of China. METHODS: This cross-sectional study included 1132 children aged 6 to 23 months in three prefectures of the Qinba Mountains area. A finger prick blood test for haemoglobin and anaemia was conducted, along with household surveys of socio-demographic characteristics, illness characteristics, and feeding practices. Multiple linear and logistic regression analyses were used to determine predictors of anaemia. RESULTS: Overall, 42.6% of children in the study displayed anaemia. Children aged 6 to 11 months had the highest anaemia prevalence (53.6%). Anaemia risk factors differed among age-groups and throughout the overall sample. Bivariate and multivariable regression results showed that continued breastfeeding, any history of formula feeding, and consumption of iron-rich or iron-fortified foods were prominent risk factors for anaemia. However, continued breastfeeding and any history of formula feeding had the greatest impact across age-groups (both P<0.05). CONCLUSION: Anaemia remains a severe public health problem among children aged 6 to 23 months in rural China. Healthy feeding practices, nutritional health knowledge, and nutrition improvement projects are needed to reduce the burden of anaemia among children in rural areas of China.

Insufficient classification of anaemia in general practice: a Danish register-based observational study.

BACKGROUND: Anaemia can be a pointer of underlying severe disease, including undiagnosed malignancy. Subsequent blood tests are essential to classify the anaemia into subtypes and to facilitate targeted diagnostic investigation to ensure timely diagnosis of underlying disease. OBJECTIVE: We aimed to describe and classify anaemia based on laboratory tests from patients with new-onset anaemia detected in general practice. An additional aim was to analyse associations between patient characteristics and unclassified anaemia (not classifiable according to an algorithm). DESIGN: Population-based cross-sectional study. SETTING: Danish general practice. SUBJECTS: A total of 62,731 patients (age: 40-90 years) with new-onset anaemia were identified in Danish laboratory information systems and nationwide registries, and data were obtained for 2014-2018. MAIN OUTCOME MEASURES: We measured the proportion of patients classified into subtypes of anaemia based on blood tests requested by general practitioners within 31 days of the anaemia index date. RESULTS: Of the 62,731 patients with new-onset anaemia, we identified unclassified anaemia in 78.9% (95% confidence interval (CI): 77.3-80.5) of men and 65.1% (CI: 63.4-66.9) of women. The likelihood of unclassified anaemia increased with age, increasing comorbidity and decreasing severity of anaemia. CONCLUSION: The majority of patients with new-onset anaemia could not be classified through a simple algorithm due to missing blood tests, which highlights a potential missed opportunity for diagnosis. Standardised laboratory testing of patients with anaemia is warranted to ensure adequate follow-up and early detection of underlying severe disease.KEY POINTSAnaemia can be a sign of malignancy, and anaemia classification is an important step in the diagnosis of underlying disorders.The majority of patients with anaemia could not be classified according to a simple algorithm due to missing blood tests.Some patient characteristics were associated with a high risk of unclassified anaemia: high age, high comorbidity, and severe anaemia.Standardised laboratory testing in patients with anaemia is needed to inform targeted diagnostic investigation to ensure timely diagnosis.

Estimates of prediabetes and undiagnosed type 2 diabetes in Denmark: The end of an epidemic or a diagnostic artefact?

Background: Up-to-date information on undiagnosed type 2 diabetes and prediabetes based on current diagnostic criteria is lacking. The study aimed to model the total numbers of people with undiagnosed type 2 diabetes and prediabetes in Denmark based on existing population-based surveys. Methods: Two population-based Danish studies with information on HbA1c, date of examination, gender, age and known type 2 diabetes were identified: the Danish General Suburban Population Study, n = 21,205, and the Danish Health Examination Survey, n = 18,065. The prevalence of known, undiagnosed and pre-diabetes were estimated in the Danish General Suburban Population Study, and population-level age-specific prevalence of known type 2 diabetes was estimated from national registers. The Danish Health Examination Survey was included for sensitivity analysis. Combining estimates of the survey participation rate among known type 2 diabetes patients with known overall participation rates from the studies allowed for the correction of survey prevalence to plausible population-level estimates of age- and gender-specific prevalence. Results: The prevalence of known, undiagnosed and pre-diabetes was highest among men, increasing with age with a peak at age 70. Applying the survey-based prevalence to the entire Danish population, the estimated number (May 2011) with undiagnosed type 2 diabetes was 60,681, corresponding to 24% of all type 2 diabetes cases, and 292,715 had prediabetes, about 50% more than the total type 2 diabetes population. Conclusions: Estimates of undiagnosed type 2 diabetes and prediabetes are dramatically lower than reported in previous studies (60,681 vs 200,000 and 292,715 vs 750,000); however, whether this reflects a true decrease in incidence or the change to HbA1c-based diagnostic criteria is not clear.

Hyperspectral imaging in wound care: A systematic review.

Multispectral and hyperspectral imaging (HSI) are emerging imaging techniques with the potential to transform the way patients with wounds are cared for, but it is not clear whether current systems are capable of delivering real-time tissue characterisation and treatment guidance. We conducted a systematic review of HSI systems that have been assessed in patients, published over the past 32 years. We analysed 140 studies, including 10 different HSI systems. Current in vivo HSI systems generate a tissue oxygenation map. Tissue oxygenation measurements may help to predict those patients at risk of wound formation or delayed healing. No safety concerns were reported in any studies. A small number of studies have demonstrated the capabilities of in vivo label-free HSI, but further work is needed to fully integrate it into the current clinical workflow for different wound aetiologies. As an emerging imaging modality for medical applications, HSI offers great potential for non-invasive disease diagnosis and guidance when treating patients with both acute and chronic wounds.

Haemoglobin trajectories during pregnancy and associated outcomes using pooled maternity and hospitalization data from two tertiary hospitals.

BACKGROUND AND OBJECTIVES: This study aimed to describe how haemoglobin trajectories in pregnant Australian women were associated with subsequent postpartum haemorrhage, blood transfusion and other outcomes. MATERIALS AND METHODS: The study was conducted in two tertiary public hospitals in Australia, using routinely collected maternity and hospital data on singleton pregnancies (2011-2015). Latent class growth modelling defined trajectories among those with at least one haemoglobin in each of three antenatal time periods (0-15, 16-30 and 31+ weeks; n = 7104). Observed over expected ratios were calculated after predicting expected outcomes with adjusted logistic regression. RESULTS: The mean minimum haemoglobin levels across the three periods were 127·9, 116·5 and 119·3 g/l. We identified seven groups of women with similar haemoglobin trajectories: five with parallel U-shaped trajectories, one with increasing and one with decreasing trajectory. Thirty-eight women (0.5%) had very low haemoglobin across the pregnancy and the highest adverse outcomes, including higher than expected blood transfusion risk. One hundred thirteen women (1.6%) with a progressively decreasing trajectory also had higher risk of transfusion. Women with high haemoglobin across the antenatal period had higher than expected risk of preterm birth, small for gestational age and infants transferred to higher care. CONCLUSIONS: Haemoglobin trajectories across pregnancy can predict women at higher risk of requiring transfusion around birth. Women who maintain high haemoglobins across the pregnancy are worthy of increased surveillance as they carry increased risks of newborn morbidity.

BOLD cardiac MRI for differentiating reversible and irreversible myocardial damage in ST segment elevation myocardial infarction.

OBJECTIVES: BOLD imaging is a quantitative MRI technique allowing the evaluation of the balance between supply/demand in myocardial oxygenation and myocardial haemorrhage. We sought to investigate the ability of BOLD imaging to differentiate reversible from irreversible myocardial injury as well as the chronological progression of myocardial oxygenation after reperfusion in patients with ST segment elevation myocardial infarction (STEMI). METHODS: Twenty-two patients (age, 60 ± 11 years; 77.3% male) with STEMI underwent cardiac MRIs on four occasions: on days 1, 3, 7 and 30 after reperfusion. BOLD MRI was obtained with a multi-echo turbo field echo (TFE) sequence on a 3-T scanner to assess myocardial oxygenation in MI. RESULTS: T2* value in MI with intramyocardial haemorrhage (IMH) was the lowest (9.77 ± 3.29 ms), while that of the salvaged zone was the highest (33.97 ± 3.42 ms). T2* values in salvaged myocardium demonstrated a unimodal temporal pattern from days 1 (37.91 ± 2.23 ms) to 30 (30.68 ± 1.59 ms). T2* values in the MI regions were significantly lower than those in remote myocardium, although the trends in both were constant overall. There was a slightly positive correlation between T2* in MI regions and EF (Rho = 0.27, p < 0.05) or SV (Rho = 0.22, p = 0.04) and a slightly negative correlation between T2* in salvaged myocardium and LVEDV (Rho = - 0.23, p < 0.05). CONCLUSIONS: BOLD MRI performed in post-STEMI patients allows accurate evaluation of myocardial damage severity and could differentiate reversible from irreversible myocardial injury. The increased T2* values may imply the pathophysiological mechanism of salvaged myocardium. BOLD MRI could represent a more accurate alternative to the other currently available options. KEY POINTS: • Myocardial oxygenation and haemorrhage after myocardial infarction affect BOLD MRI values • BOLD MRI could be used to differentiate irreversible from reversible myocardial damage • Changed oxygenation implies the pathophysiological mechanism of salvaged myocardium.

Evidence for embryonic haemoglobins from Sparus aurata under normal and hypoxic conditions.

Teleost haemoglobins vary in polymorphisms and primary structure, although display similar functional properties. Key amino acids for Root effect (a reduction in oxygen-carrying capacity and loss of cooperativity with declining pH) are conserved throughout fish evolution. For the first time, we cloned and characterised Sparus aurata L. embryonic globin chains (eα1, eα2, eß). We also studied haemoglobins (eHbI, eHbII) behaviour in normal and low-oxygen conditions. Several amino acids in fry globins are different in chemical type (e.g. polar → non-polar and vice versa), compared to adult globins. His55α1, crucial for Root effect, is substituted by Ala in fry, presumably enhancing oxygen capture, transport and reducing the dependence of Root effect from pH. Phylogenetic trees demonstrate that eα1 globin diversified more recently than eα2; moreover, eα1, eα2 and eß globins evolved earlier than adult α and ß globins. In low-oxygen conditions, fry haemoglobins display the same behaviour of the adult haemoglobins (probably, embryonic and adult-type I Hbs display a higher oxygen affinity than type II Hbs, operating through a rapid cycle of heme-Fe auto-oxidation/reduction). Therefore, based on our results and on the comparison with adult haemoglobins, we hypothesise that embryonic haemoglobins have evolved to better adapt fry to variable habitats. We studied Sparus aurata for its economical relevance in Mediterranean aquaculture. The information we provide can help understand Sparus aurata behaviour in the wild and in rearing conditions. Further studies with functional assays will deepen the knowledge on the molecular mechanisms of fry haemoglobin physiology.

Absence of Arabidopsis Polyamine Oxidase 5 Influences the Cytokinin-Induced Shoot Meristem Formation from Lateral Root Primordia.

Lateral root primordia (LRPs) of Arabidopsis can be directly converted to shoot meristems (SMs) by the application of exogenous cytokinin. Here, we report that Arabidopsis POLYAMINE OXIDASE 5 (AtPAO5) contributes to this process, since the rate of SM formation from LRPs was significantly lower in the pao5-2 knockout mutant. Furthermore, the presented experiments showed that AtPAO5 influences SM formation via controlling the thermospermine (T-Spm) level. Gene expression analyses supported the view that the pao5-2 mutation as well as exogenous T-Spm downregulate the expression of the class 3 haemoglobin coding genes AtGLB1 and AtGLB2. AtGLB1 and 2 have been reported to augment cytokinin sensitivity, indirectly inhibiting the expression of type-A ARABIDOPSIS RESPONSE REGULATORs (ARRs). In agreement, the same ARR-coding genes were found to be upregulated in the pao5-2 mutant. Although GLB proteins might also control cytokinin-induced nitric oxide (NO) accumulation, we could not find experimental evidence for it. Rather, the negative effect of NO-donor treatment on AtPAO5 gene expression and SM formation was seen. Nevertheless, a hypothetical pathway is set up explaining how AtPAO5 may affect direct shoot meristem formation, controlling cytokinin sensitivity through T-Spm and GLBs.

Haemoglobin Concentration and Cognitive Ability in the Aberdeen Children of the 1950s.

Introduction Haemoglobin concentrations decrease with age. Abnormally low and high haemoglobin concentrations are associated with reduced cognition; however, the evidence for these associations in cohort data is limited. This study aims to assess the relationship between haemoglobin concentration and cognition in a well-characterised cohort of older adults. Methods Two hundred and fifty-two healthy participants were drawn from the Aberdeen Children of the 1950s cohort, aged between 59 to 65 years. Participants underwent cognitive tests of processing speed, memory, verbal and nonverbal reasoning, and language ability and these were used to construct a global cognitive score, g, using principal component analysis. Haemoglobin concentration in the blood was measured concurrently. Hierarchical multiple regression models were constructed assessing the relationship between haemoglobin concentration and each cognitive measure and these were corrected for age, sex, education, C-reactive protein, hypertension, and body mass index. Results Significant linear association between haemoglobin concentration and nonverbal reasoning demonstrated that low haemoglobin levels are associated with lower scores. A quadratic relationship was found for haemoglobin concentration and immediate memory scores in which low and high haemoglobin levels were associated with lower scores. Conclusions Haemoglobin concentration was found to have a significant linear association with nonverbal reasoning scores and a significant quadratic association with memory scores. The results from this study help to understand the association between haemoglobin and different aspects of cognition.

Changing reference intervals for haemoglobin in Denmark: Clinical and financial aspects.

INTRODUCTION: Based on international experiences and altering demography the reference intervals (RI) for haemoglobin (Hb) concentrations in blood were changed in Denmark in 2013 from 113 - 161 g/L to 117 - 153 g/L for women and from 129 - 177 g/L to 134 - 170 g/L for men. The aim of this study was to determine the derived change in prevalence of anaemia and the change in yearly health care costs of diagnostic investigations associated with the expected, as we hypothesized, increased prevalence and health care costs. MATERIALS AND METHODS: Data from 96,314 non-hospitalised patients (55,341 females and 40,973 males, aged 18 - 105 years) from general practitioners and community specialists of Funen, Denmark, were extracted from the laboratory information system. The prevalence of anaemia according to the new and the old RI were investigated, and additional costs were calculated based on estimated additional blood analyses and nationally recommended endoscopic procedures. RESULTS: Changing the Hb RI increased the number of anaemic patients by 52% (3450 patients) over a two-year period. With new RI the proportion of anaemic elderly above 80 years was 20.5% for females and 43.9% for males. Annual costs of derived additional assessments due to the altered RI were estimated to be 5.7 million €, which equals the cost of 1214 knee replacement surgeries in Denmark. CONCLUSIONS: Changing the Hb RI has been expensive, despite the fact that no outcome studies have justified the alteration. The methodological approach for establishing new RI, here particularly for Hb, should be thoroughly considered. In general, physicians should use RI with caution.

P3 Fraction: Effect on HbA1c Values by HPLC.

INTRODUCTION: The availability of the haemoglobin A1c test has been a major advance in diabetic care and its measurement has become an integral part for the management of diabetes. When glycated haemoglobin (HbA1c) is estimated by High Performance Liquid Chromatography (HPLC), one of the fractions that are eluted is known as "P3" fraction which is labelled as "degenerated haemoglobin". The P3 fraction is not taken into account while estimating HbA1c or HbA values. AIM: To study the effect of P3 on the final reported value of HbA1c by HPLC and the significance of this fraction in the final chromatogram. The possibility that HbA1c fraction is under reported due to increase in P3 fraction was also examined. MATERIALS AND METHODS: HbA1c, various fractions of HbA1 and P3 were estimated by HPLC method in 430 subjects. Patient data was divided into 3 groups on the basis of HbA1c% (group I - <6%, group II - 6 - 12%, group III - >12%). RESULT: P3% as well as P3 area increases as the HbA1c increases (p-value - <0.001). Statistical significant increase was seen as HbA1c% increases, P3% also increases and correlation (r = 0.6) became stronger with increasing HbA1c levels. HbA1a%, HbA1b% fraction increases with increase in HbA1c% and HbA1a area, HbA1b area also shows the same increase with increasing HbA1c%. CONCLUSION: From this study we conclude that sub fractions of glycated haemoglobin and P3 fraction influence the final reported value of HbA1c by HPLC. P3 fraction might indicate the possible presence of variant haemoglobin in the sample.

Bridging Theory and Experiment to Address Structural Properties of Truncated Haemoglobins: Insights from Thermobifida fusca HbO.

In this chapter, we will discuss the paradigmatic case of Thermobifida fusca (Tf-trHb) HbO in its ferrous and ferric states and its behaviour towards a battery of possible ligands. This choice was dictated by the fact that it has been one of the most extensively studied truncated haemoglobins, both in terms of spectroscopic and molecular dynamics studies. Tf-trHb typifies the structural properties of group II trHbs, as the active site is characterized by a highly polar distal environment in which TrpG8, TyrCD1, and TyrB10 provide three potential H-bond donors in the distal cavity capable of stabilizing the incoming ligands. The role of these residues in key topological positions, and their interplay with the iron-bound ligands, has been addressed in studies carried out on the CO, F(-), OH(-), CN(-), and HS(-) adducts formed with the wild-type protein and a combinatorial set of mutants, in which the distal polar residues, TrpG8, TyrCD1, and TyrB10, have been singly, doubly, or triply replaced by a Phe residue. In this context, such a complete analysis provides an excellent benchmark for the investigation of the relationship between protein structure and function, allowing one to translate physicochemical properties of the active site into the observed functional behaviour. Tf-trHb will be compared with other members of the group II trHbs and, more generally, with members of the other trHb subgroups.

Evaluation of the anti-nitrative effect of plant antioxidants using a cowpea Fe-superoxide dismutase as a target.

Nitric oxide cytotoxicity arises from its rapid conversion to peroxynitrite (ONOO(-)) in the presence of superoxide, provoking functional changes in proteins by nitration of tyrosine residues. The physiological significance of this post-translational modification is associated to tissue injury in animals, but has not been yet clarified in plants. The objective of this study was to establish new approaches that could help to understand ONOO(-) reactivity in plants. A recombinant Fe-superoxide dismutase from cowpea (Vigna unguiculata (L.) Walp.), rVuFeSOD, was the target of the ONOO(-)-generator SIN-1, and the anti-nitrative effect of plant antioxidants and haemoglobins was tested in vitro. Nitration on rVuFeSOD was evaluated immunochemically or as the loss of its enzymatic activity. This assay proved to be useful to test a variety of plant compounds for anti-nitrative capacity. Experimental data confirmed that rice (Oryza sativa L.) haemoglobin-1 (rOsHbI) and cowpea leghaemoglobin-2 exerted a protective function against ONOO(-) by diminishing nitration on rVuFeSOD. Both plant haemoglobins were nitrated by SIN-1. The chelator desferrioxamine suppressed nitration in rOsHbI, indicating that Fe plays a key role in the reaction. The removal of the haem moiety in rOsHbI importantly suppressed nitration, evidencing that this reaction may be self-catalyzed. Among small antioxidants, ascorbate remarkably decreased nitration in all tests. The phenolic compounds caffeic acid, gallic acid, pyrogallol, 4-hydroxybenzoic acid and the flavonoid gossypin also diminished tyrosine nitration and protected rVuFeSOD to different extents. It is concluded that small plant antioxidants, especially ascorbate, and haemoglobins may well play key roles in ONOO(-) homeostasis in vivo.

The diversity of 2/2 (truncated) globins.

Small size globins that have been defined as 'truncated haemoglobins' or as '2/2 haemoglobins' have increasingly been discovered in microorganisms since the early 1990s. Analysis of amino acid sequences allowed to distinguish three groups that collect proteins with specific and common structural properties. All three groups display 3D structures that are based on four main α-helices, which are a subset of the conventional eight-helices globin fold. Specific features, such as the presence of protein matrix tunnels that are held to promote diffusion of functional ligands to/from the haem, distinguish members of the three groups. Haem distal sites vary for their accessibility, local structures, polarity, and ligand stabilization mechanisms, suggesting functional roles that are related to O2/NO chemistry. In a few cases, such activities have been proven in vitro and in vivo through deletion mutants. The issue of 2/2 haemoglobin varied biological functions throughout the three groups remains however fully open.

Haemoglobins of Mycobacteria: structural features and biological functions.

The genus Mycobacterium is comprised of Gram-positive bacteria occupying a wide range of natural habitats and includes species that range from severe intracellular pathogens to economically useful and harmless microbes. The recent upsurge in the availability of microbial genome data has shown that genes encoding haemoglobin-like proteins are ubiquitous among Mycobacteria and that multiple haemoglobins (Hbs) of different classes may be present in pathogenic and non-pathogenic species. The occurrence of truncated haemoglobins (trHbs) and flavohaemoglobins (flavoHbs) showing distinct haem active site structures and ligand-binding properties suggests that these Hbs may be playing diverse functions in the cellular metabolism of Mycobacteria. TrHbs and flavoHbs from some of the severe human pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae have been studied recently and their roles in effective detoxification of reactive nitrogen and oxygen species, electron cycling, modulation of redox state of the cell and facilitation of aerobic respiration have been proposed. This multiplicity in the function of Hbs may aid these pathogens to cope with various environmental stresses and survive during their intracellular regime. This chapter provides recent updates on genomic, structural and functional aspects of Mycobacterial Hbs to address their role in Mycobacteria.

The globins of cyanobacteria and algae.

Approximately, 20 years ago, a haemoglobin gene was identified within the genome of the cyanobacterium Nostoc commune. Haemoglobins have now been confirmed in multiple species of photosynthetic microbes beyond N. commune, and the diversity of these proteins has recently come under increased scrutiny. This chapter summarizes the state of knowledge concerning the phylogeny, physiology and chemistry of globins in cyanobacteria and green algae. Sequence information is by far the best developed and the most rapidly expanding aspect of the field. Structural and ligand-binding properties have been described for just a few proteins. Physiological data are available for even fewer. Although activities such as nitric oxide dioxygenation and oxygen scavenging are strong candidates for cellular function, dedicated studies will be required to complete the story on this intriguing and ancient group of proteins.

The globins of cold-adapted Pseudoalteromonas haloplanktis TAC125: from the structure to the physiological functions.

Evolution allowed Antarctic microorganisms to grow successfully under extreme conditions (low temperature and high O2 content), through a variety of structural and physiological adjustments in their genomes and development of programmed responses to strong oxidative and nitrosative stress. The availability of genomic sequences from an increasing number of cold-adapted species is providing insights to understand the molecular mechanisms underlying crucial physiological processes in polar organisms. The genome of Pseudoalteromonas haloplanktis TAC125 contains multiple genes encoding three distinct truncated globins exhibiting the 2/2 α-helical fold. One of these globins has been extensively characterised by spectroscopic analysis, kinetic measurements and computer simulation. The results indicate unique adaptive structural properties that enhance the overall flexibility of the protein, so that the structure appears to be resistant to pressure-induced stress. Recent results on a genomic mutant strain highlight the involvement of the cold-adapted globin in the protection against the stress induced by high O2 concentration. Moreover, the protein was shown to catalyse peroxynitrite isomerisation in vitro. In this review, we first summarise how cold temperatures affect the physiology of microorganisms and focus on the molecular mechanisms of cold adaptation revealed by recent biochemical and genetic studies. Next, since only in a very few cases the physiological role of truncated globins has been demonstrated, we also discuss the structural and functional features of the cold-adapted globin in an attempt to put into perspective what has been learnt about these proteins and their potential role in the biology of cold-adapted microorganisms.