Latest News on blood disease : July – 2020

Chronic graft-versus-host disease after allogeneic blood stem cell transplantation

The incidence, characteristics, risk factors for, and impact of chronic graft-vs-host disease (GVHD) were evaluated in a consecutive series of 116 evaluable HLA-identical blood stem cell transplant recipients. Minimum follow-up was 18 months. Limited chronic GVHD occurred in 6% (95% confidence interval [CI], 0%-13%), and clinical extensive chronic GVHD in 71% (95% CI, 61%-80%). The cumulative incidence was 57% (95% CI, 48%-66%). In univariate analyses, GVHD prophylaxis other than tacrolimus and methotrexate, prior grades 2 to 4 acute GVHD, use of corticosteroids on day 100, and total nucleated cell dose were significant risk factors for clinical extensive chronic GVHD. On multivariate analysis, GVHD prophylaxis with tacrolimus and methotrexate was associated with a reduced risk of chronic GVHD (hazard ratio [HR], 0.35; P = .001), whereas the risk was increased with prior acute GVHD (HR, 1.67;P = .046). When adjusted for disease status at the time of transplantation, high-risk chronic GVHD had an adverse impact on overall mortality (HR, 6.6; P < .001) and treatment failure (HR, 5.2; P < .001) at 18 months. It was concluded that there is a substantial rate of chronic GVHD after HLA-identical allogeneic blood stem cell transplantation, that clinical factors may alter the risk of chronic GVHD, and that high-risk chronic GVHD adversely affects outcome. [1]

Stimulus rate determines regional brain blood flow in striate cortex

Intravenous bolus administration of oxygen 15‐labeled water and positron emission tomography were used to measure changes in brain blood flow induced by two modes of photic stimuli over a wide range of repetition rates. These stimuli (patterned‐flash and reversingd checkerboard) were chosen in order to determine whether stimulus luminacne or stimulus frequency was reponsible for previously observed increased in blood flow in the striate cortex during photic stimulation. The response curves of blood flow change as a function of stimuls rate were nearlyl suggest that elementary stimulus variables, such as repetition rate, can have a major effect on local cerebral responses, as measured with positron emission tomography and other radiotracer methods. [2]

Arterial blood gases and pH during sleep in chronic obstructive pulmonary disease

Arterial blood gases were measured during 7 hours of sleep in 15 patients with severe stable chronic obstructive pulmonary disease (COPD); 6 awake patients with COPD studied in recumbency for an average of 5 hours served as controls. Mean maximal decrease in arterial oxygen partial pressure (PaO2) (± SD) was 13.5 ± 3.9 mm Hg for sleeping patients (p <0.005) and 5.5 ± 1.7 mm Hg for controls (p < 0.05); comparable increases for PaCO2 were 8.3 ± 4.4 mm Hg (p < 0.005) and 4.7 ± 1.7 mm Hg (p < 0.1), respectively. Changes in pH during sleep were of the magnitude expected with acute changes in arterial carbon dioxide partial pressure (PaCO2) in patients with chronic hypercapnia. Consistent changes In heart rate, respiratory frequency or cardiac rhythm were not observed during sleep.

Nocturnal worsening of hypoxemia could be explained by alveolar hypoventilation in six sleeping patients and in five controls; in nine sleeping patients, further impairment of ventilation-perfusion mismatch also contributed to worsening of hypoxemia. There was no relationship between the decrease in PaO2 during sleep and the degree of airways obstruction or the PaO2 level when awake. Because of low PaO2, when awake, a fall in PaO2 during sleep brings values into the steep part of the oxyhemoglobin dissociation curve where slight changes in PaO2 result in marked changes in oxygen content. All patients with COPD whose waking PaO2 was below 60 mm Hg had PaO2 below 50 mm Hg during sleep; nocturnal oxygen therapy should be considered in such patients, particularly in the presence of polycythemia or troublesome right-sided heart failure. [3]

ABO and Rh Blood Group System and Periodontal Disease – A Prevalence Study

Background: Varied literature is documented exploring the relationship between ABO blood group and prevalence of oral and dental diseases. The aim of this study was to investigate the correlation of periodontal disease with “ABO” blood groups and Rhesus factor.

Materials and Methods: A total of 684 systemically healthy subjects who were non smokers were selected by chance. Subjects with known blood group who had at least 20 teeth, were included in the study and the blood groups were confirmed from their medical records. Based on the periodontal parameters like clinical attachment loss (CAL) and bleeding on probing (BOP) the subjects were divided into three groups: healthy, gingivitis and periodontitis. The percentage distribution of ABO blood groups and Rhesus factor among the groups was tabulated.

Results: There was an increased prevalence of gingivitis in subjects with blood group ‘A’ and periodontitis in subjects with blood group ‘O’, while subjects with blood group ‘B’ had healthy periodontium. There was higher prevalence of gingivitis in Rh positive group.

Conclusion: A significant relationship between blood typing and periodontal disease was determined in this study. Further research into this is indicated. [4]

Reference

[1] Przepiorka, D., Anderlini, P., Saliba, R., Cleary, K., Mehra, R., Khouri, I., Huh, Y.O., Giralt, S., Braunschweig, I., Van Besien, K. and Champlin, R., 2001. Chronic graft-versus-host disease after allogeneic blood stem cell transplantation. Blood, The Journal of the American Society of Hematology, 98(6), pp.1695-1700.

[2] Fox, P.T. and Raichle, M.E., 1985. Stimulus rate determines regional brain blood flow in striate cortex. Annals of Neurology: Official Journal of the American Neurological Association and the Child Neurology Society, 17(3), pp.303-305.

[3] Koo, K.W., Sax, D.S. and Snider, G.L., 1975. Arterial blood gases and pH during sleep in chronic obstructive pulmonary disease. The American journal of medicine, 58(5), pp.663-670.

[4] Anup, P., Siddhartha, V., Girish, S., Keshava, A., Sameer, Z. and Vishwajeet, K. (2016) “ABO and Rh Blood Group System and Periodontal Disease – A Prevalence Study”, Journal of Advances in Medicine and Medical Research, 16(5), pp. 1-6. doi: 10.9734/BJMMR/2016/24055.

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