Hyperacute rejection after single lung transplantation: a case report

Hyperacute rejection is a well-known complication in kidney and heart transplantations. However, its occurrence in lung transplantation is extremely rare, with only 4 cases previously described. A 53-year-old female patient blood type O with end-stage chronic obstructive pulmonary disease underwent left lung transplantation. She had 2 negative pretransplantation evaluations for panel-reactive antibodies. One hour after the vascular clamps were released, progressive hypoxia developed. Fiberoptic bronchoscopy revealed an optimal bronchial anastomosis; an abundant pink frothy fluid was observed on the allograft side. Chest X ray sevealed a completely opacified left lung. Due to the low-compliance of the transplanted lung and the risk for native lung hyperinsufflation, independent mechanical ventilation was employed. Despite all measures, multiple organ failure developed and the patient died 24 hours after the procedure. A necropsy evaluation for confirmed the patency of all anastomoses and no signs of ischemia. Retrospectively, a new evaluation for panel-reactive antibodies was performed, with 24% reactivity. Complement-dependent cytotoxicity crossmatch was negative, however, a flow cytometric analysis was positive for both HLA-I (56%) and HLA-II (45%). Further investigation detected an anti-A2 in the recipient serum and the donor had an A2 antigen. Hyperacute rejection is a rare posttransplantation complication highlighted by its precocity and lethality. With the increased number of lung transplantations performed yearly, it is believed that its incidence will also rise. Therefore, prompt diagnosis and familiarity with management strategies are fundamental.     

Ephaptic coupling of cortical neurons

The electrochemical processes that underlie neural function manifest themselves in ceaseless spatiotemporal field fluctuations. However, extracellular fields feed back onto the electric potential across the neuronal membrane via ephaptic coupling, independent of synapses. The extent to which such ephaptic coupling alters the functioning of neurons under physiological conditions remains unclear. To address this question, we stimulated and recorded from rat cortical pyramidal neurons in slices with a 12-electrode setup. We found that extracellular fields induced ephaptically mediated changes in the somatic membrane potential that were less than 0.5 mV under subthreshold conditions. Despite their small size, these fields could strongly entrain action potentials, particularly for slow (<8 Hz) fluctuations of the extracellular field. Finally, we simultaneously measured from up to four patched neurons located proximally to each other. Our findings indicate that endogenous brain activity can causally affect neural function through field effects under physiological conditions.     

Cleland's and Grayson's ligaments of the hand: a morphometrical investigation

The cutaneous ligaments of the human digits are delicate functional structures essential for normal skin stability during digital movements. These ligaments extend bilaterally between the phalanx and the finger dermis, either posteriorly (Cleland's ligaments) or anteriorly (Grayson's ligaments) to the digital neurovascular bundles. We have performed a series of detailed anatomical dissections of the human digits so as to investigate morphometrically Cleland's and Grayson's ligaments and their topographic arrangements. Data were statistically compared between fingers, respecting both side (left or right) and sex, in an attempt to clarify some of the morphologic variations of these structures. The cutaneous ligaments of the human digits have been analyzed bilaterally both in 30 fixed cadavers (300 adult human digits) and in 10 nonfixed human cadaveric digits. A computerized morphometrical investigation of the human digits and their Cleland's and Grayson's ligaments has been performed and the resulting quantitative data have been statistically assessed, comparing groups according to finger, phalanx, side (left or right hands), and sex. The ratio between the origin and insertion (O:I) of these ligaments indicate a divergent arrangement of fibers, with values varying from 0.52 to 0.84, depending on the phalanx and finger analyzed. Our morphometrical data provide normal reference values, mainly for Grayson's ligaments, that can be useful in the comparison with the respective measurements obtained in Dupuytren's disease. Morphological bases are also provided, which may be relevant either in computerized tomography or magnetic resonance imaging involving the hand region and in their application in surgical procedures of the human hand.     

Magnetic resonance imaging of gadolinium-labeled pancreatic islets for experimental transplantation

New imaging techniques that couple anatomical resolution to sensitivity may greatly contribute to improving islet transplantation. In the present work, a report is given of the direct detection of islets by magnetic resonance imaging (MRI) after ex vivo cell labeling with the MRI T(1) contrast agent GdHPDO3A. Experiments on mouse and human islets demonstrated well-tolerated uptake of GdHPDO3A, based on morphology, viability, glucose-dependent insulin response and apoptosis/toxicity gene array profile. GdHPDO3A loading was sufficient for in vitro MRI cell detection. In vivo isotransplanted mouse islets into the kidney capsule and xenotransplanted human islets within the mouse liver were detected. Imaging specificity was supported by the absence of signal in unlabeled islet transplants, its persistence upon using fat-suppression MRI protocols and the colocalization with the transplanted islets. In conclusion, direct islet imaging with high spatial and contrast resolution after labeling with GdHPDO3A is demonstrated, allowing visualization of kidney subcapsular mouse islet grafts and intrahepatic human islet xenografts.     

High-Resolution genomic arrays identify CNVs that phenocopy the chromosome 22q11.2 deletion syndrome

The 22q11 Deletion Syndrome includes the overlapping phenotypes of DiGeorge/Velocardiofacial Syndromes, characterized by conotruncal heart defects, cleft palate, thymus, and parathyroid gland dysplasia. The majority (90%) of patients harbor detectable chr22q11.2 deletions, but a genetic etiology for the remainder of patients without a deletion can remain undefined despite major birth defects. We analyzed DNA from eight patients with normal 22q11 FISH studies by high-density single nucleotide polymorphism (SNP) arrays and identified potentially pathogenic copy number variants (CNVs) in four of eight patients. Two patients showed large CNVs in regions of known genomic disorders: one a deletion of distal chr22q11.2 and the other a duplication of chr5q35. A 3-Mb deletion of chr19p13.3 that includes a gene associated with conotruncal heart defects was found in a third patient. Two potentially pathogenic CNVs were found in a fourth patient: a large heterozygous deletion of chr6p24 and a smaller duplication of chr9p24. Our findings support a recent consensus statement advocating chromosomal microarray analysis as a first-line diagnostic approach for patients with multiple congenital anomalies. In patients with phenotypes suggestive of the 22q11.2 syndrome spectrum and normal FISH, microarray analysis can uncover the molecular basis of other genomic disorders whose features overlap those of 22q11.2 deletions.     

Ultrasound detection of spontaneous rupture of accessory spleen: A case report

Accessory spleen rupture can induce acute abdominal bleeding following minimal trauma or by atraumatic mechanisms. Spleen rupture is more frequent in pediatric patients and those affected by hematological diseases. We described the case of a 59-year-old male patient affected by hereditary spherocytosis referred to the emergency department for abdominal left side pain. An early ultrasound performed in the emergency department allowed to diagnosed hemoperitoneum by spontaneous bleeding of hypertrophic accessory spleen. Although abdomen computed tomography is the diagnostic method of choice, ultrasound can early detect sign of emoperitoneum in the emergency setting in case of hemodinamically unstable patient.