Cerebral hemodynamics during neonatal transition according to mode of delivery

Cerebral haemodynamics during the immediate transition period in neonates may differ depending on whether delivery is vaginal or by caesarean section. However, these differences have never been confirmed by near-infrared time-resolved spectroscopy (TRS). Therefore, the purpose of this study was to compare cerebral blood volume (CBV) and cerebral haemoglobin oxygen saturation (ScO2) between healthy term neonates by mode of delivery. Subjects were 31 healthy term neonates who did not require resuscitation. Thirteen neonates were delivered vaginally (VD group) and 18 were delivered by elective caesarean section (CS group). Absolute oxyhaemoglobin, deoxyhaemoglobin, and total haemoglobin concentrations were measured continuously by TRS; oxyHb × 100/totalHb (ScO2) (%) and CBV (mL/100 g brain tissue) were also calculated. Measurements were started as soon as possible after birth, obtained from 1 to 2 min after birth, and continued until 15 min after birth. CBV was significantly higher in the VD group than in the CS group in the 4 min after birth but not thereafter. There were no significant between-group differences in ScO2 and SpO2. These findings indicate that there is a difference in cerebral haemodynamic patterns in the first 4 min after delivery between term neonates by mode of delivery when CBV is monitored by TRS.

Optical density based quantification of total haemoglobin concentrations with spectroscopic optical coherence tomography

Spectroscopic optical coherence tomography (sOCT) has emerged as a new possibility for non-invasive quantification of total haemoglobin concentrations [tHb]. Recently, we demonstrated that [tHb] measured in ex-vivo human whole-blood with a conventional sOCT system achieves a precision of 9.10 g/dL with a bias of 1.50 g/dL. This precision improved by acquiring data with a combination of focus tracking and zero-delay acquisition (FZA) that compensated for experimental limitations, increasing to 3.80 g/dL with a bias of 1.50 g/dL. Nevertheless, sOCT precision should improve at least to $$\sim 2$$ ∼ 2 g/dL to be clinically relevant. Therefore, sOCT-based [tHb] determinations require the development of new analysis methods that reduce the variability of [tHb] estimations. In this work, we aim to increase sOCT precision by retrieving the [tHb] content from a numerical optimisation of the optical density (OD), while considering the blood absorption flattening effect. The OD-based approach simplifies previous two-step Lambert–Beer fitting approaches to a single step, thereby reducing errors during the fitting procedure. We validated our model with ex-vivo [tHb] measurements on flowing whole-blood samples in the clinical range (7–23 g/dL). Our results show that, with the new model, conventional sOCT can determine [tHb] with a precision of 3.09 g/dL and a bias of 0.86 g/dL compared to a commercial blood analyser. We present further precision improvement by combining the OD methodology with FZA, leading to a precision of 2.08 g/dL with a bias of 0.46 g/dL.

Quantitative assessment of infusion pump-mediated haemolysis in feline packed red blood cell transfusions

Objectives Haemolysis caused by the use of peristaltic infusion pumps (PIPs) has been described in human and canine packed red blood cells (pRBCs). The aim of this study was to evaluate the effects of two different linear PIPs on the haemolysis of feline pRBC units stored for a long time. Methods Feline pRBC units stored with adenine, dextrose, mannitol and sodium chloride (SAGM) were manufactured. After 35–42 days of storage at 2–4°C, a line administration system with a 180 µm filter was attached to every pRBC bag, the system was drained by gravity alone (8 drops/min) and a 1.3 ml sample was collected (G). A NIKI V4 pump was then used at a flow rate of 25 ml/h, the flow was stopped when the infusion system was filled with blood coming from the infusion pump and another 1.3 ml sample was collected (NK). Finally, an Infusomat FmS pump was evaluated, collecting another 1.3 ml sample (IM). Packed cell volume (PCV) was measured in all samples by microhaematocrit centrifugation, total haemoglobin (HGB) was measured using a specific haemoglobin analyser and, after centrifugation, free HGB was determined by spectrophotometry. The percentage of haemolysis was calculated. Friedman’s test was used to compare the samples. Results Fifteen feline pRBC units were evaluated. The average degree of haemolysis for sample G (gravity-assisted) was 1.12%. Comparison of the degree of gravity-assisted haemolysis with haemolysis in PIP NK (1.13%) and IM (1.14%) samples revealed no significant differences, with differences of only 0.01% and 0.02%, respectively. Conclusions and relevance The results of this study demonstrate that the use of two common PIPs in veterinary hospitals does not produce levels of haemolysis that are significantly different than that caused by gravity alone during transfusion of feline pRBCs at a rate of 25 ml/h.

CHANGES IN BLOOD PARAMETERS IN BREEDER TOMS FOLLOWING SUBCUTANEOUS INJECTION WITH CADMIUM

Alterations in blood biochemical values of Yearling breeder toms following parenteral administration of cadmium (Cd) were well evaluated. Each treated member of a pair of (total 24 pairs) 0f toms received a single dose of 4.5mg of Cd per kg. body weight (0.04-mole). The birds were sacrificed at 0,6,24 and 192 hours : post-treatment. Highly significant (P<0.0001).increase in serum Cd concentration was observed in the Cd-injected toms, Reduction in the blood have been used to produce useful serum Cd (P<0.05) at the successive post-necropsy periods indicated systematic clearance of the metal from the fluid. Nearly 50 percent eliminated by 24 h post-treatment. Serum changes glutamic pyruvic transaminase (SGPT) was due to the similarly increased (P<0.05) in the Cd-treated birds and was presumed to have originated mainly from damaged skeletal muscle tissues. The cadmium treatment did not affect (P>0.05) serum testosterone level, total protein, total haemoglobin, lactate dehydrogenase, packed cell volume or serum glutamic oxaloacetic transaminase. It was concluded from these observations that the Cd treatment did not seem to have interfered seriously with renal or hepatic functions, iron, copper and zinc metabolism or caused significant damage to myocardial issue.

The Unsuspected Intrinsic Property of Melanin to Dissociate the Water Molecule, Implications in Pulmonary Biology

Life originated in anoxia, but paradoxically many organisms came to depend upon oxygen for survival, independently evolving diverse respiratory systems for expel CO2 and acquiring oxygen to and from the environment, respectively. Thereby, Oxygen, a vital gas, and a lethal toxin, represents a trade-off with which all organisms have had a conflicted relationship. The study of oxygen movements in the tissues of the human body has been a matter of great interest ever since centuries. In the beginning of the past century, Dr. Christian Bohr and August Krogh’s work on respiratory physiology and capillary modelling using mathematical models to calculate molecular transport in microcirculation, trying to determine the negative impact of lack of oxygen transport to tissues. Supposedly, computer simulation allowed investigation of the dynamic and non-linear characteristics of the systems. But the results have been and are contradictory. In Germany, Dietrich Werner Lubbers (1917-2005) obtained several patents related to designs for the study of gases in tissues. The aim of Dietrich Lübbers’ research was to understand the entire pathway and regulation of oxygen transport from the blood into the mitochondria. Assessment of pO2 histograms on most organs, revealed a remarkable similarity under physiological conditions: a Gaussian distribution always with less than 5% of values less than 5mmHg. Other studies detected changes in the concentrations of oxy- ([HbO2]) deoxy- ([HHb]) and total haemoglobin ([HbT]=[HbO2]þ [HHb]) measured using near infrared spectroscopy (NIRS) [1]. It has been shown that diabetic rats have markedly decreased oxygen availability in the kidney, supposedly resulting from increased oxygen consumption [2]

Total haemoglobin – a reference measuring system for improvement of standardisation

BackgroundTotal haemoglobin (Hb) concentration in blood belongs to the most requested measurands, and the HiCN method (hemiglobincyanide) is accepted as a reference. Although the reaction principle is clearly characterised, measurement conditions and settings are not consistently defined, some of them influencing the results. An improvement of standardisation is the object.MethodsAfter method optimization, measurement results between different calibration laboratories (CL) were compared with each other and also with results of the National Metrology Institute of Germany (PTB), with target values of certified reference material, within the RELA scheme, and to >1500 results from routine laboratories.ResultsOverall deviations between three CLs were ≤0.5% (n = 24 samples) in a measurement range of 20 g/L to 300 g/L. A CV of 0.4% was determined in pooled blood (1 year long-term imprecision, 99.0%–101.1% recovery of the mean). For selected measurements (n = 4 samples) the PTB participated without significant differences to three CLs, and no significant differences were observed comparing CLs to certified values of reference materials. The expanded measurement uncertainty (probability 95%) was estimated as 1.1%.ConclusionsA reference measuring system, comprising measuring instruments and other devices, including reagents and supply, to generate reference measurement values for total Hb concentration of high accuracy and low measurement uncertainty is presented. Measurement parameters are investigated and defined. The reference measuring system is ready to offer service to EQA providers and to the IVD industry for certifying control materials or calibrators.

Dose-response modelling of total haemoglobin mass to hypoxic dose in elite speed skaters

The aim of the present study is the modelling of the total haemoglobin mass responses in altitude environment with the dose-response model in elite endurance athletes and comparison different existing approaches in the quantification of hypoxic dose.Data from seven healthy elite endurance athletes specialised in middle distance speed skating participated in the study: six males (24±1.8 years, 182 ±0.3 cm, 84 ±1.5 kg, BMI 23.2±0.6 kg/m2, 59.3±1.5 ml/kg/min) and one female (21 years, 164 cm, 56 kg, BMI 17.1 kg/m2, 59.9 ml/kg/min). Data were collected during a 3-month training period which included two training camps (14 +14 days) at sea level and two training camps (21+21 days) at altitude of 1224 m and 1850 m above sea level. Total haemoglobin mass (tHb-mass) were measured before the start of the season (baseline) and before and after each training camp (seven measurements) using an optimized CO-rebreathing method, training loads and oxygen saturation at altitude were measured and hypoxic dose were calculated.Mean total haemoglobin mass for the male group at the base line were 1067±83 g, before the training camp 1 were 1095±82 g, after TC1 1113±105 g, before the training camp 2 (TC2) 1107±88 g, after TC2 1138±104 g. For the female athlete at the base line were 570 g, after TC1 564 g, after TC2 582 g.The increase of tHb-mass after TC2 were 3,25% and were significant (p<0,005). Mean hypoxic dose for the male group TC1 were %·h (98%) 1078±157, %·h (95%) 79±57, and km.h 473±1 and at TC2 were %·h(98%) 1586±585, %·h (95%) 422±182, and km.h 893±18 and were different from TC1 (p<0,05) for %·h (95%) and km.h methods. For the female athlete hypoxic dose at TC1 were %·h (98%) 970, %·h (95%) 32, and km.h 470 and at TC2 were %·h(98%) 1587, %·h (95%) 289, and km.h 900.The relationship between hypoxic dose and haematological response was analysed with a non-linear model. The magnitude of the increase of the total haemoglobin mass were investigated using simulation procedures based upon individual responses to the hypoxic dose. We introduced a measurement error to the list square method as a way of avoiding overfitting problem. Dose-response mathematical model between hypoxic dose and total haemoglobin mass was developed. Modelled total haemoglobin mass was within measurement error range. This model is suitable for the computer simulations. The individual response to hypoxic dose due to model data was different. Maximal values in total haemoglobin mass that can be achieved by male athletes according to the model was 1321.9 ± 32 g. The model predicted that (τ) erythrocyte life span is 73.8 ± 9.0 days. Moreover, highest value of individual tHb-mass increase after returning to the sea level according to the model was16.3 ±0.7 days.The model developed in the current study describes the time course of total haemoglobin mass during altitude exposure and post-altitude decline in elite speed skaters.