Biogenesis and delivery of extracellular vesicles: harnessing the power of EVs for diagnostics and therapeutics

Extracellular vesicles (EVs) are membrane-enclosed particles secreted by a variety of cell types. These vesicles encapsulate a diverse range of molecules, including proteins, nucleic acids, lipids, metabolites, and even organelles derived from their parental cells. While EVs have emerged as crucial mediators of intercellular communication, they also hold immense potential as both biomarkers and therapeutic agents for numerous diseases. A thorough understanding of EV biogenesis is crucial for the development of EV-based diagnostic developments since the composition of EVs can reflect the health and disease status of the donor cell. Moreover, when EVs are taken up by target cells, they can exert profound effects on gene expression, signaling pathways, and cellular behavior, which makes these biomolecules enticing targets for therapeutic interventions. Yet, despite decades of research, the intricate processes underlying EV biogenesis by donor cells and subsequent uptake by recipient cells remain poorly understood. In this review, we aim to summarize current insights and advancements in the biogenesis and uptake mechanisms of EVs. By shedding light on the fundamental mechanisms governing EV biogenesis and delivery, this review underscores the potential of basic mechanistic research to pave the way for developing novel diagnostic strategies and therapeutic applications.

Amebic Liver Abscess and Kawasaki Disease

BACKGROUND

Co-occurrence of amebic hepatitis and Kawasaki disease has not been reported previously.

CASE CHARACTERISTICS

We describe two children (aged 4 y and 5 y) with Kawasaki disease and coexisting liver abscess. They were treated with intravenous immunoglobulins with/without percutaneous drainage in combination with amebicidal agents.

OUTCOME

Both the children were completely cured of the amebic hepatitis, and had normalization and regression of coronaries at follow-up.

MESSAGE

We report the co-existence of amebic hepatitis with Kawasaki disease.

Ubiquitin-like (UBX)-domain-containing protein, UBXN2A, promotes cell death by interfering with the p53-Mortalin interactions in colon cancer cells

Mortalin (mot-2) induces inactivation of the tumor suppressor p53's transcriptional and apoptotic functions by cytoplasmic sequestration of p53 in select cancers. The mot-2-dependent cytoprotective function enables cancer cells to support malignant transformation. Abrogating the p53-mot-2 interaction can control or slow down the growth of cancer cells. In this study, we report the discovery of a ubiquitin-like (UBX)-domain-containing protein, UBXN2A, which binds to mot-2 and consequently inhibits the binding between mot-2 and p53. Genetic analysis showed that UBXN2A binds to mot-2's substrate binding domain, and it partly overlaps p53's binding site indicating UBXN2A and p53 likely bind to mot-2 competitively. By binding to mot-2, UBXN2A releases p53 from cytosolic sequestration, rescuing the tumor suppressor functions of p53. Biochemical analysis and functional assays showed that the overexpression of UBXN2A and the functional consequences of unsequestered p53 trigger p53-dependent apoptosis. Cells expressing shRNA against UBXN2A showed the opposite effect of that seen with UBXN2A overexpression. The expression of UBXN2A and its apoptotic effects were not observed in normal colonic epithelial cells and p53-/- colon cancer cells. Finally, significant reduction in tumor volume in a xenograft mouse model in response to UBXN2A expression was verified in vivo. Our results introduce UBXN2A as a home defense response protein, which can reconstitute inactive p53-dependent apoptotic pathways. Inhibition of mot-2-p53 interaction by UBXN2A is an attractive therapeutic strategy in mot-2-elevated tumors.

The Effect of High-Fidelity Simulation on the Confidence and Decision-Making Ability of Anaesthesia Trainees in Managing Subsequent Simulated ‘Can't Intubate, Can't Oxygenate’ scenarios

The decision to attempt a percutaneous airway in a recognised ‘Can't Intubate, Can't Oxygenate’ (CICO) situation may occur too late to avoid a poor outcome. Our study was designed to investigate the effect of high-fidelity simulation on the confidence and decision-making ability of anaesthesia trainees in managing CICO scenarios in subsequent simulation. Nine anaesthesia trainees from Logan Hospital participated. Pre-study questionnaires surveying confidence levels in various anaesthetic crises were completed. All participants underwent an education session based on algorithms developed for failed intubation and ventilation, and techniques for securing percutaneous airway access. However, only four of the nine participated in a high-fidelity simulation session. All nine participants were then filmed during ‘mini-simulation’ assessment sessions and completed post-study questionnaires identical to those at the commencement of the study. The four trainees who had undertaken the initial high-fidelity simulation had a lower median time to laryngeal mask airway attempt (60 versus 115 seconds) and time to percutaneous airway attempt (111 versus 172 seconds) in the subsequent simulation. The median number of deviations from the Difficult Airway Society algorithm was 0 for the simulation group compared to 1 for the non-simulation group. This small study suggests that high-fidelity simulation shortens the decision-making time of anaesthesia trainees in subsequent simulated CICO scenarios. This observation warrants follow-up in larger prospective trials.

An attempt to measure the spread of emergency medicine internationally

OBJECTIVE

To determine the feasibility of using the internet to track the spread of emergency medicine internationally.

OVERVIEW

This was an attempt to perform a descriptive cross-sectional study employing a web-based survey.

SUBJECTS

Potential respondents were identified from multiple sources.

OBSERVATIONS

The primary outcome was the response to 16 questions about EM care and the setting in which it was delivered for acute cardiac, paediatric, obstetrical illnesses and trauma. The questions were divided into six general areas and elicited for urban, semi-urban and rural settings. A series of four e-mails soliciting completion of the survey were sent to potential respondents.

ANALYSIS

Simple descriptive statistics.

RESULTS

We identified 358 potential respondents with valid e-mail addresses over a period of three years. Overall, 145 (41%) responded and 117 (33% 95% CI 28-38%) of them were complete and interpretable. There was one response from 54 and two responses from 29 countries, representing an overall response rate by country surveyed of 65% (95% CI 57-73%), but of all existing countries of only 43% (95% CI 36-50%). Based on sparse data, it appears that in urban areas, 47% (obstetrics) to 65% (paediatric) of acutely sick or injured patients are taken to an ED-equivalent. For rural areas, this range was 19% (obstetrical) to 40% (trauma). CT scans are available in 78% of urban ED-equivalents but 12% of rural ones. Haematocrits are available in 72% of rural settings. In 60% of responding nations, some type of EM training was available, and in 42% physicians went abroad to study EM.

CONCLUSIONS

A survey of international EM is challenging to achieve because of difficulty in both identifying and in contacting potential respondents. Based on sparse data, population density (urban, rural) appears to be related to both the location to which acutely ill patients are taken for their care and to the level of technology available. The specialty of EM is now recognised internationally and education in EM is common.

Accelerated germ cell apoptosis in sex chromosome aneuploid fetal human gonads

The purpose of the study was to examine the occurrence of programmed cell death (apoptosis) in normal and chromosomally aneuploid testis and ovaries during the second trimester of human development. Such information may be useful in understanding normal and abnormal germ cell development and disorders associated with infertility in adult life. Apoptosis was studied by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) analysis in human fetal ovaries (n = 16) and testis (n = 14) between 9 and 23 weeks of development, in ovaries of four Turner's syndrome fetuses (45X) and in the gonad of an XO/XY fetus. In normal fetal testis, a small proportion of germ cells, Sertoli cells and Leydig cells undergo apoptosis. In normal fetal ovaries, some developing oocytes and granulosa cells were detected as TUNEL positive. Semiquantitative analysis of fetal ovaries revealed that approximately 3-7% of oocytes were apoptotic. In abnormal fetal testis (XO/XY genotype). TUNEL analysis revealed that only germ cells not enclosed in seminiferous tubules undergo apoptosis. TUNEL analysis of the Turner's syndrome (45X) ovaries studied at 15 and 20 weeks of development revealed massive apoptosis of the oocytes. Nearly 50-70% of the oocytes were TUNEL positive in these ovaries. These results suggest that germ cell apoptosis is a common event occurring during development of human gonads. Chromosomal defects by some means accelerates apoptosis that probably leads to gonadal dysgenesis later in life.

Spontaneous expulsion of unusual tracheobronchial foreign body

An extremely rare case of long, thin and sharp pin in a young boy which was inhaled initially and defied removal at branchoscopy was eventually recovered in stool after a long and variable course through alimentary tract has been reported.

Relation between effective utilization of exogenous fat emulsion as energy substrate and oxygen metabolism after surgery

It is known that fat oxidation is increased in patients who have sustained surgical stress, but it is not clear whether fat emulsion should be administered during the early postoperative period. The aim of this study was to evaluate the utilization of exogenous fat emulsion after major surgery. Total parenteral nutrition composed of glucose/amino acids or glucose/amino acids/fat was administered for 6 days to 18 patients who had undergone esophagectomy. The caloric intake was significantly less than the resting energy expenditure (REE), and there was no difference in substrate utilization in either group up to postoperative day (POD) 2. After POD 4, fat utilization was significantly increased in the fat group. The total ketone body concentration was higher in the fat group than in the glucose group on POD 1 and 2. The arterial ketone body ratio (AKBR), which reflects the rate of turnover of the Krebs cycle, was positively correlated with the caloric intake/REE ratio. It was negatively correlated with the oxygen delivery index, oxygen consumption, and lactate concentration between POD 0 and POD 2. The lactate concentration was decreased and the AKBR was increased by POD 4. Fat emulsion was effectively utilized as energy substrate after POD 4, after the relative tissue hypoxia had improved and the AKBR had increased. The utilization of exogenous fat emulsion was closely related to deficient caloric intake and oxygen metabolism.

Eicosapentaenoic acid reduces pulmonary edema in endotoxemic rats

BACKGROUND

Recently, eicosapentaenoic acid (EPA) was found to have an anti-inflammatory effect attributable to diminished synthesis of arachidonic acid metabolites that initiate acute lung injury. We evaluated the ability of dietary EPA supplementation to prevent endotoxin-induced acute lung injury in rats.

MATERIALS AND METHODS

Rats fed a standard diet were divided randomly into two groups: for 2 weeks one group additionally was fed 1000 mg/kg/day of EPA ethyl ester emulsion (EPA rats), while in the other group the diet was supplemented with vehicle alone (control rats). Fatty acid components of alveolar macrophages (AM) were measured, as well as leukotriene (LT) B(4) and LTB(5) production by AM exposed in vitro to calcium ionophore A23187. Plasma concentrations of thromboxane (Tx) B(2), a stable metabolite of TxA(2), were examined 1 h after inducing lung injury with endotoxin (2 mg/kg iv). At 6 h, wet/dry (W/D) weight ratios were calculated for the lungs to assess pulmonary edema, and neutrophils were counted in pulmonary parenchyma and peripheral blood.

RESULTS

Arachidonic acid content and LTB(4) generation in AM were significantly lower in EPA rats than in controls; conversely, EPA content and LTB(5) generation in AM were significantly higher in the EPA group. Neutrophil counts in lung parenchyma and peripheral blood did not differ between groups, but W/D and plasma TxB(2) concentrations were significantly lower in EPA rats.

CONCLUSIONS

EPA supplementation depressed arachidonic acid content and LTB(4) generation in AM and plasma TxB(2) in our model, leading to decreased pulmonary edema.

Effect of surgery on neutrophil leukotriene B4 generation and arachidonic acid content

The effect of surgery on neutrophil leukotriene B₄ (LTB₄) generation and arachidonic acid content was examined in 9 patients undergoing major surgery for esophageal cancer and 10 patients undergoing lesser surgery. Plasma IL-8 and neutrophil LTB₄ generation was increased significantly 6 h after surgery regardless of the extent of surgery. This finding was associated with a decrease in neutrophil arachidonate content. In patients who underwent major surgery, neutrophil LTB₄ generation decreased progressively on the 1st, 2nd, and 4th postoperative days, and this decrease paralleled a further decrease in neutrophil arachidonate content. These findings suggest that neutrophils are activated by surgery, thereby consuming their arachidonic acid, and that neutrophil LTB₄ generation is influenced by postoperative arachidonate levels.

Punctate thymic calcification in infants with untreated Langerhans' cell histiocytosis: report of four new cases

Four new cases of punctate thymic calcification in infants with untreated Langerhans' cell histiocytosis (LCH) are added to the four previously reported cases. All cases were shown on CT scans; plain films were rarely diagnostic. Pathologic correlation remains elusive since the usual biopsies of the LCH have been on skin or bone biopsies. A single prior pathologic study of the thymus in untreated LCH showed microscopic calcospherites. The thymic punctate calcific densities in patients with LCH may represent further accretion so that the calcospherites become macroscopic. The finding of such punctate calcific densities in an enlarged thymus of an infant with skin or bone or lung disease is strongly suggestive of LCH.

Fat emulsion administration in the early postoperative period in patients undergoing esophagectomy for carcinoma depresses arachidonic acid metabolism in neutrophils

The aim of this study was to evaluate the effect of fat emulsion administration on neutrophil arachidonic acid and leukotriene B4 (LTB4) generation in surgically stressed patients. Total parenteral nutrition was administered to 17 patients for 2 wk after esophagectomy for carcinoma. Eight patients received fat with glucose (fat group, 30% of total calories) and 9 patients received glucose (glucose group) as a non-protein calorie source from the day of the operation to the seventh postoperative day (POD), and they gradually were converted to enteral nutrition during the second postoperative week. The arachidonic acid in the fat group decreased in the serum from POD 4 to 14. and in neutrophils from 12 h after the beginning of surgery to POD 14, compared to preoperative levels. LTB4 production by A23187-stimulated neutrophils was highest 6 h after the beginning of surgery, when neutrophil arachidonic acid concentration was decreasing, and then fell below the preoperative value from POD 4 to 14 in both groups. LTB4 production on POD 14 was lower in the fat group than in the glucose group. Biosynthesis of arachidonic acid from linoleic acid is inhibited in surgically stressed patients receiving fat emulsion, resulting in the diminished synthesis of LTB4 by neutrophils. The decrease in LTB4 may diminish chemotactic and chemokinetic signals to other leukocytes.

Massive hemorrhage after biopsy of an esophageal polyp

Esophageal vascular malformations are very rare. Herein, we describe a rare polyp formed by an abnormally large vessel that bled profusely after biopsy. Despite endoscopic procedures, the patient continued to bleed and underwent emergency surgery. Histopathological examination revealed an abnormally large blood vessel with a thick wall in the upper part of the lamina propria mucosae and covered by squamous cell epithelium. The elevated lesion, which was endoscopically diagnosed a small polyp, was in fact an abnormally large artery covered by squamous cell epithelium. Massive bleeding after biopsy of an esophageal polyp is apparently so rare that it has not, as yet, been described.

Oxygen delivery as a factor in the development of fatal postoperative complications after oesophagectomy

BACKGROUND

This study was designed to assess the impact of oxygen transport variables on outcome in 115 patients undergoing elective surgery for oesophageal carcinoma.

METHODS

Haemodynamic parameters were determined using a Swan-Ganz catheter in all patients on the day before operation, 6 h after operation, and daily for the first 4 days after operation.

RESULTS

Oxygen delivery and consumption at 6 h were significantly higher in survivors than in non-survivors. However, oxygen delivery and consumption in both groups did not differ significantly after postoperative day 1. Of 17 patients with oxygen delivery levels lower than 445 ml min-1 m-2 at 6 h, eight died in hospital. Oxygen delivery in patients who developed either an anastomotic leak or severe pneumonia was significantly lower 6 h after surgery. Lower levels of oxygen delivery preceded postoperative complications.

CONCLUSION

Oxygen delivery 6 h after oesophagectomy correlates with postoperative complications and may be a determinant of hospital mortality.

The efficacy of podiatric orthoses as an adjunct to the treatment of plantar ulceration in leprosy

This study examines the outcome of a management approach to plantar ulceration secondary to leprotic neuropathy. Locally-available resources were used to produce podiatric orthoses which were supplied to an experimental group. The effects on healing time and quality of healing were compared with a control group. Both groups were ambulant (the programme sought not to interfere with socioeconomic independence). Using standard nonparametric methods of analysis, it was demonstrated that the effects on healing rate, attributed to the experimental intervention, were highly significant. Over a 7-month period, 57% of the experimental group ulcers healed, while only 12.5% of the control group ulcers healed. The experimental intervention also demonstrated a positive effect on the quality of ulcer healing. This effect was not reflected in the control group.

Segmental spinal dysgenesis. A disorder different from spinal agenesis

We reviewed the clinical and roentgenographic findings, treatment, and results for seventeen patients (six male and eleven female) who had segmental spinal dysgenesis, a disorder frequently confused with, but distinct from, lumbar and lumbosacral agenesis. The average age at the time of presentation to the Minnesota Spine Center or the Gillette Children's Hospital was two and a half years (range, newborn to twenty-one years), and the average duration of follow-up was eight years (range, five months to twenty-two years). At the time of the diagnosis, eight patients had neurological deficits: seven had a neurogenic bladder and four had weakness of the lower extremities. An average of 2.6 procedures (range, one to five procedures) was needed to obtain a solid fusion. Decompression of the stenotic canal was performed in ten patients, and it was followed by an improvement in neurological function in two of them. A solid fusion of the spine, arrest of the progressive kyphosis, and stabilization of neurological function were obtained in all patients. We recommend early anterior and posterior arthrodesis in patients who have segmental spinal dysgenesis, as the progressive kyphosis that inevitably develops often results in neurological deficits.

Lymph node metastasis and the recurrence of esophageal carcinoma with emphasis on lymphadenectomy in the neck and superior mediastinum

A series of 335 patients with squamous cell carcinoma of the thoracic esophagus undergoing resection and reconstruction via a right thoracotomy and laparotomy with cervical anastomosis between 1973 and 1990, were reviewed. Prior to 1982, the removal of lymph nodes was limited to the nodes in the mediastinum below the tracheal bifurcation and upper abdomen (142 patients). Nodal metastases were found in 89 of these patients at operation. The upper abdominal nodes were the most frequent sites of metastasis (47.2%). None of the 38 patients with positive nodes sampled from the neck and superior mediastinum survived for more than 45 months. In the 50 patients with recurrences, 30 were in the neck and/or superior mediastinum. During or after 1983, the superior mediastinal nodes, particularly the bilateral recurrent nerve nodal chains, were routinely removed (193 patients). Nodal metastasis was proven in 131 of the 193 patients, in whom 87 (45.1%) had metastasis in the neck and superior mediastinum. Eleven of these 87 patients survived for 45 months or more. In the 61 patients with recurrences, 20 were in the neck and/or superior mediastinum. These data suggest that recurrent nerve nodal chains should be removed to improve survival in patients with esophageal carcinoma.

[Correlation between respiratory or circulatory state and postoperative extravascular lung water volume in patients undergoing surgery for esophageal carcinoma of the thorax]

Postoperative extravascular lung water index (EVLWI, ml/kg) was analyzed in 30 patients who underwent esophagectomy through right thoracotomy for esophageal carcinoma from the day of operation to 5th postoperative day, in order to clear the correlation between respiro-circulatory state and EVLWI. The results are as follows. 1. EVLWI on 1st postoperative day correlated significantly not only with blood loss during operation (p < 0.01, r = 0.65) but also with systemic vascular resistance index on 1st postoperative day (p < 0.05, r = -0.43). 2. EVLWI correlated with the respiratory index (RI) on the 2nd and 4th postoperative day (p < 0.01), suggesting that EVLWI is an important indicator in judging the respiratory state following esophagectomy. 3. EVLWI on 4th postoperative day correlated with accumulative fluid balance up to 4th postoperative day (p < 0.05, r = 0.41), however neither correlated with other hydrostatic parameters nor the COP-PCP gradient. Furthermore, EVLWI on 4th postoperative day correlated more significantly with oxygen consumption index (p < 0.05, r = 0.58) than that with accumulative fluid balance up to 4th postoperative day. According to those results, the increased systemic vascular permeability immediately after the surgery attributes to the increase of EVLWI on the 1st postoperative day. Whereas, the increased EVLWI on 4th postoperative day depends on not only the hydrostatical factors but also the increased pulmonary vascular permeability caused by the surgical maneuver to the lung during esophageal surgery.

Postoperative diuresis renography and ultrasound in patients undergoing pyeloplasty. Predictors of surgical outcome

The authors reviewed 50 pediatric patients (56 renal units) who underwent pyeloplasty and had serial preoperative and postoperative diuresis renogram and ultrasound studies. Of those patients that clinically improved with surgery, 73% and 91% showed improved renographic patterns in postoperative studies at 3 and 12 months, respectively. Ultrasound demonstrated more gradual improvement in grade and pelvic diameters over longer study intervals. Diuresis renography is an excellent predictor of surgical outcome within 3 months of pyeloplasty and showed change well in advance of that seen on ultrasound. Sonography is better suited to longer term evaluation of grade, pelvic diameter, and renal size.

Epidemiology of streptococcal infection with reference to rheumatic fever

Antistreptolysin antibodies were estimated in 787 normal children and young adults by latex test. This test detects titres of 200 IU/ml and above, which is the western cut off point, for diagnosis. Children below one year showed no antibodies. Unlike western studies where no antibodies are detected below the age of 3 years, our study revealed that 7.9% children between 1-3 years had significantly elevated antibodies. This epidemiological pattern is well reflected in the different clinical profile of younger children developing rheumatic heart disease in our country. Antibodies progressively increased with age--11.8% in 4-8 years group to 15.8% in 9-12 years age group. All these were from the lower socio-economic group. ASO was positive in 16.7% of young adults from lower socio-economic status while it was positive only in 9.2% in the upper socio-economic status. A total of 522 patients of rheumatic carditis were studied. Only 23.4% had no antibodies or less than 200 IU/ml, and 77% were positive (26.9% had greater than 400 IU/ml and 49.7% had 200 IU/ml). Throat swab culture and ASO antibodies were done simultaneously in 76 outdoor patients, clinically diagnosed as acute bacterial pharyngitis. Group A beta hemolytic streptococci were isolated in 64% and significant antistreptolysin antibodies were seen in 62%. School health records were scanned in more than 50,000 school children. Point prevalence of rheumatic heart disease was estimated to be 0.17% in lower and 0.05% in upper socio-economic groups. Age and socio-economic factors are important variables in epidemiology of streptococcal infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Inflammatory pseudotumor of the mesentery and small intestine

Three cases of abdominal inflammatory pseudotumor or inflammatory myofibroblastic tumor of the small intestinal mesentery are presented with additional examples from the literature. An abdominal mass was detected in three preadolescent children who presented with fever, growth failure, hypochromic anemia, thrombocytosis and polyclonal hypergammaglobulinemia. The radiographic findings confirmed the presence of a mass. Following surgical resection, the systemic manifestations dramatically resolved. The solid mesenteric mass was composed of spindle cells with the features of myofibroblasts and mature plasma cells and small lymphocytes. Clinical follow-up confirmed the benign nature of this lesion with no signs of recurrence in any patient from 3 to 6 years after the initial surgery.

Malignant carcinoid tumors in children

The clinical, light microscopic, and ultrastructural features of four malignant carcinoid tumors in children, three boys and one girl ages 8--14 years, are described. Extensive metastases to multiple organs were present in three, and in the fourth child there was diffuse local infiltration of the bowel wall, which resembled a lymphoma. The primary tumor arose in the ileum in one child and in the transverse colon in another. In two children, the primary sites could not be determined; one patient is still alive and in the other, permission for autopsy was refused. Electron microscopy showed moderate numbers of neurosecretory granules in some cells in all cases. One patient with extensive metastases showed repeated partial response to radiotherapy and chemotherapy. Eight benign appendiceal carcinoids were seen at the same hospital over the same period, suggesting malignant carcinoids may be more common in children than often assumed.

The roentgenographic findings of Hirschsprung's disease in newborns and infants

A descriptive survey of this not uncommon disorder from one specialty's point of view.