PubMed · 2783106
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K Pietrzik. 1989. Folate deficiency: morphological and functional consequences.. https://doi.org/10.1159/000417308
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BACKGROUND: A minority of blood donors are Rh(D)-negative, and Rh(D)-negative red blood cell (RBC) products are often overutilized. As such, Rh(D)-negative RBCs may be difficult to maintain in blood bank inventory. STUDY DESIGN AND METHODS: We changed our blood bank laboratory policy to approve non-alloimmunized Rh(D)-negative patients to receive Rh(D)-positive RBCs for routine transfusion under defined criteria. Those criteria included Rh(D)-negative males (all ages) and females (aged >50 years) who were designated as do not resuscitate (DNR), either with or without intubation, in the electronic medical record. RESULTS: From August 15, 2024 through August 15, 2025, a total of 204 Rh(D)-negative patients met the above criteria and were approved to receive routine Rh(D)-positive RBC transfusions. Within that group, 23 patients received Rh(D)-positive RBCs. The remaining patients either did not require transfusion or were issued Rh(D)-negative RBC units. Since implementing this practice, a total of 68 Rh(D)-negative units were conserved during this time frame. Notably, 28 of the 68 units (41%) were type O, Rh(D)-negative. DISCUSSION: Rh(D)-positive RBCs can be routinely given to non-alloimmunized Rh(D)-negative patients who are not at risk for developing hemolytic disease of the fetus and newborn (HDFN). By creating clear guidelines for the routine administration of Rh(D)-positive RBCs to patients who are not at risk for HDFN, the inventory of Rh(D)-negative RBC units can be directed to those patients who would most benefit from this limited resource.
Ultrasound microbial cell disrupters operating at around 20 kHz are often physically large and, due to significant heating, can be unsuitable for small sample volumes where biochemical integrity of the extracted product is required. Development of a compact device based on a 63.5-mm diameter, 6.5-mm thick tubular transducer for rapid cell disruption in small-volume samples in a high-intensity acoustic cavitation field with minimal temperature rises is described here. Suspensions of Saccharomyces cerevisiae were exposed to cavitation for various times in the compact device and a 20-kHz probe sonicator. Cell disruption was assessed by protein release and by staining. Yeast cell disruption was greater in the novel 267-kHz sonicator than in the 20-kHz probe sonicator for the same exposure time. A 1-dimensional (1-D) transfer matrix model analysis for piezoelectric resonators was applied to an axial cross-section of the tubular sonicator to predict frequencies of mechanical resonance in the sample volume associated with maximum acoustic pressure. Admittance measurements identified frequencies of electrical resonance. Ultrasonic cavitation noise peaks were detected by a hydrophone at both the mechanical and electrical resonances. Cell breakage efficiency was twice as great in terms of protein released per dissipated watt at the mechanical resonance predicted by the model, compared to those at the electrical resonance frequencies. The results form a basis for rational design of an ultrasound cell disruption technique for small-volume samples.
A high-vacuum low-temperature atomic force microscope (AFM) for the direct observation of freeze-fracture samples has been developed. This AFM has a freeze-fracture mechanism inside the vacuum chamber. With this AFM it is possible to observe the fractured surface directly without both fabricating a replica and exposure to the ambient atmosphere. Both sandwich and knife fracture methods have been achieved to obtain freeze-fracture surfaces and after deep etching. A fine structure of the fractured red blood cell membrane has been observed using both methods. These are relatively quick and easy methods for the observation of freeze-fracture surfaces without introducing replica artifacts.