O等位基因引起ABO基因型与表现型定型差异

保证输血时血清学方面的安全,首要的是对受血者与献血者ABO血型定型,血清学检查通常分两个步骤.正定型通常使用鼠源单克隆抗体检测红细胞表面是否存在A或B抗原.互补的实验即反定型,利用当红细胞上缺乏A或B抗原时,人群可天然产生相对应的抗体的原理,检测血清中是否存在抗-A或者抗-B抗体.确定了受血者红细胞表面的ABO抗原以及血浆中的抗体,便能确定血型,为其提供相合的血液.     

Heterogeneous phenotypes of platelet and plasma von Willebrand factor in obligatory heterozygotes for severe von Willebrand disease

To characterize the heterogeneity of severe (type III) von Willebrand disease (vWD), plasma and platelet von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (Ricof) were measured in 28 obligatory heterozygotes (ie, parents or children of probands from 15 different kindreds with severe vWD). On the average, heterozygotes had low levels of vWF in both platelets and plasma. There was, however, considerable heterogeneity, with four distinct patterns. Eleven heterozygotes had concordant reduction of vWF:Ag and Ricof in both plasma and platelets; five had low levels of vWF:Ag and Ricof in plasma contrasting with normal levels in platelets; eight had a peculiar pattern, the reverse of the above (ie, low levels in platelets and normal levels in plasma); and in one, both vWF measurements were normal in plasma and platelets. These patterns were genetically determined: they were consistent in four couples of consanguineous heterozygotes and in two couples carrying the same gene deletion. Only the remaining three heterozygotes had no clearly identifiable pattern. Other findings of this study were that although most of the heterozygotes had normal bleeding times, the 7 of 28 who had prolonged bleeding times had concordantly low levels of vWF measurements in both plasma and platelets. In conclusion, this large series of obligatory heterozygotes provides evidence for phenotypic and genotypic heterogeneity of severe vWD.     

Artificial intelligence in gastroenterology: A state-of-the-art review

The development of artificial intelligence (AI) has increased dramatically in the last 20 years, with clinical applications progressively being explored for most of the medical specialties. The field of gastroenterology and hepatology, substantially reliant on vast amounts of imaging studies, is not an exception. The clinical applications of AI systems in this field include the identification of premalignant or malignant lesions (e.g., identification of dysplasia or esophageal adenocarcinoma in Barrett’s esophagus, pancreatic malignancies), detection of lesions (e.g., polyp identification and classification, small-bowel bleeding lesion on capsule endoscopy, pancreatic cystic lesions), development of objective scoring systems for risk stratification, predicting disease prognosis or treatment response [e.g., determining survival in patients post-resection of hepatocellular carcinoma), determining which patients with inflammatory bowel disease (IBD) will benefit from biologic therapy], or evaluation of metrics such as bowel preparation score or quality of endoscopic examination. The objective of this comprehensive review is to analyze the available AI-related studies pertaining to the entirety of the gastrointestinal tract, including the upper, middle and lower tracts; IBD; the hepatobiliary system; and the pancreas, discussing the findings and clinical applications, as well as outlining the current limitations and future directions in this field.     

The growth hormone responses to octreotide in acromegaly correlate with adenoma somatostatin receptor status

We studied the correlation between the presence of somatostatin (SRIH) receptors in GH secreting tumors and the in vivo GH responsiveness to the SRIH analog octreotide in 11 acromegalic patients. To test in vivo octreotide (SMS 201-995) responsiveness, the patients were given a single dose (100 micrograms, sc) and their plasma GH levels were measured for several hours. Somatostatin receptor content was measured by receptor autoradiography on frozen tumor tissue sections using either a somatostatin-28 analog or a SRIH octapeptide analog (Tyr3-octreotide) as iodinated radioligands. In eight acromegalic patients, who had complete and long lasting GH inhibition after octreotide administration, SRIH receptors with high affinity for octreotide were distributed homogeneously in the tumor tissue. Two patients had moderate, short duration, and incomplete inhibition of GH secretion after octreotide administration, and their tumors had very low capacity and/or affinity SRIH receptors. A further patient who had a moderate response to octreotide had SRIH receptors that were nonhomogeneously distributed throughout the tumor. These data suggest that the therapeutic efficacy of octreotide may be related to tumor SRIH receptor levels; the best in vivo responses to octreotide occurred in patients whose tumors contained a high density of homogeneously distributed receptors which had a high affinity for octreotide.     

Effects on the buoyant density of rabbit platelets of ADP and agents that increase the concentration of cyclic AMP

Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.     

Impact of the COVID-19 Pandemic on Health-Related Concerns,Quality of Life and Psychological Adjustment in Young Adults with Congenital Heart Disease

Background: The risk for a severe disease course in case of infection with SARS-CoV-2 in young adults with congenital heart disease is largely unknown, potentially leading to uncertainty and anxiety among affected patients. This study aims to investigate health-related concerns, health-related quality of life and psychological adjustment in patients with congenital heart disease compared to healthy peers during the COVID-19 pandemic. Methods: One-hundred patients with congenital heart disease and 50 controls (M = 29.7, SD = 3.8 years) were recruited. They completed an online survey including the assessment of health-related concerns regarding COVID-19, the 12-item Short Form Health Survey and the Brief Symptom Inventory. Results: Patients considered COVID-19 to be a more serious issue (Generalized odds ratio [GenOR] = 1.67, p = 0.04), were more concerned about becoming infected (GenOR = 2.93, p < 0.001) and expressed more fear about leaving their homes (GenOR = 1.81, p = 0.004) while general anxiety symptoms were not different between groups (p = 0.23). Patients relied more on family and friends for support (30% vs. 2% in controls, p < 0.001) and reported better compliance with protective measures (p = 0.03). Mental health-related quality of life and psychological adjustment were not different between groups (p = 0.17 and p = 0.68, respectively). Physical health-related quality of life was lower in patients compared to controls (p = 0.03). Conclusions: Young adults with congenital heart disease in Switzerland are more concerned about their health during the COVID-19 pandemic compared to healthy peers. These concerns, however, do not translate into generally impaired mental wellbeing. The impact of the easing of lockdown measures on long-term anxiety levels and quality of life requires further study