Vascular Communication Research Articles

Hemobilia: an unusual and life threatening complication of laparoscopic cholecystectomy

Hemobilia though rare, occurs due to abnormal vascular and biliary communication established as a result of trauma, gallstones, neoplasms, inflammatory process and vascular disorders. It can rarely complicate a laparoscopic cholecystectomy as a result of hepatic artery injury, clip migration, clip erosion, diathermy and subsequent arteriobiliary fistula, or pseudoaneurysm eroding into the extra hepatic bile ducts. A 34 years female underwent laparoscopic cholecystectomy for cholelithiasis, suffered bile leak that settled on by 13th postoperative day, met with sudden right upper abdominal pain and hypovolemic shock on 15th postoperative day due to massive hemobilia arising out of rupture of pseudoaneurysm of the right hepatic artery into the biliary system. Urgent CT Angiography showed a large pseudoaneurysm of right hepatic artery branch with adjacent small collection, IHBR and CBD dilatation suggestive of hemobilia. Emergency CT guided trans-arterial hepatic artery embolization done to control hemobilia and save the patient. An immediate CT angiography for early diagnosis, in all postoperative laparoscopic cholecystectomy cases with suspicion of hemobilia due to an underlying hepatic artery pseudoaneurysm, followed by CT guided trans-arterial hepatic artery embolization forms the gold standard management in such patients.

Extracellular Matrix-Associated Factors Play Critical Roles in Regulating Pancreatic β-Cell Proliferation and Survival.

This review describes formation of the islet basement membrane and the function of extracellular matrix (ECM) components in β-cell proliferation and survival. Implications for islet transplantation are discussed. The insulin-producing β-cell is key for maintaining glucose homeostasis. The islet microenvironment greatly influences β-cell survival and proliferation. Within the islet, β-cells contact the ECM, which is deposited primarily by intraislet endothelial cells, and this interaction has been shown to modulate proliferation and survival. ECM-localized growth factors, such as vascular endothelial growth factor and cellular communication network 2, signal through specific receptors and integrins on the β-cell surface. Further understanding of how the ECM functions to influence β-cell proliferation and survival will provide targets for enhancing functional β-cell mass for the treatment of diabetes.

Single-Port/Pneumovagina Technique for Two Further Applications

ObjectiveTo demonstrate a novel technique to surgically treat certain vaginal conditions. DesignTechnical video demonstrating 2 cases in which the technique is used. SettingGynecological Minimally Invasive and Robotic Surgery Unit at Clínica Universitaria (private clinic), Concepción, Chile. InterventionsLocal institutional review board was consulted, and this study was exempted from approval. Institutional ethics committee approved the study and publication of these data. A 35-year-old woman with a bicornuate unicollis uterus presented with dyspareunia. Her examination revealed an incomplete longitudinal vaginal septum. Her right hemivagina was slightly wider than the left one. With the patient under spinal anesthesia, we performed a complete resection of the septum using the single-port/pneumovagina technique (SPPT). A 36-year-old woman who was nulligravida presented with dyspareunia. On clinical exam she had a 3-cm leiomyoma in the proximal vaginal third. Doppler-powered pelvic ultrasound ruled out any vascular communication with the cervix. We performed a vaginal myomectomy using the SPPT under spinal anesthesia. In this particular case we used a fourth trocar in the gel cap to use a myoma screw. With this technique we created a pneumovagina occluding the introitus with the aid of a single-port device (GelPoint Path; Applied Medical, Rancho Santa Margarita, CA). We selected this particular device, designed for transanal surgery, because its access channel avoids gas leakage after applying gentle pressure on the cap. The working cannel is 4 × 4.5 cm, and up to 4 trocars can be inserted in the gel cap. We use 12 mm Hg of pressure to create the pneumovagina and 5 L/min flow to maintain it. Similar approaches have been described for treating eroded and/or infected sacrocolpopexy mesh [1–3]. One could question the utility of this approach over conventional vaginal surgery, and in this sense we believe it provides both the surgeon and surgical assistant a much more comfortable and ergonomic position while performing surgery. It also improves the view of anatomic structures for the surgical team, which in conventional vaginal surgery is limited only to the surgeon. Both procedures were uneventful. The operation time for the first patient was 5 minutes, and the patient was discharged 4 hours later. The operation time for the second patient lasted 35 minutes, and she was discharged 12 hours later. ConclusionThe creation of a pneumovagina with the application of a single-port device provides an excellent view of vaginal structures and allows the application of laparoscopic techniques to perform vaginal surgeries in a much more ergonomic fashion compared with conventional vaginal surgery.

Adam Christian Thebesius' Channels into the Human Heart: the Thebesian Veins and the Thebesian Valve.

In 1708, Adam Christian Thebesius, a 22-year-old student at Leiden University, presented his graduate thesis, Disputatio medica inauguralis de circulo sanguinis in corde. More than a doctoral dissertation, this groundbreaking work opened new channels into the study of the human coronary venous system. Thebesius' theory about the vascular communication between the coronary arteries and the chambers of the heart helped to advance understanding of hemodynamic principles and to clarify the physiologic pathways of the coronary circulation. The following article-the third in a trilogy about Lower Silesian scientists-provides an overview of the life story and achievements of this Silesian physician and innovator, whose name was immortalized in 2 cardiac eponyms: the Thebesian veins and the Thebesian valve.

Abstract WP298: Communication Center Guided Prehospital Stroke Assessment Scoring has High Inter-rater Agreement

Introduction: We are prospectively validating a model of communication center guided prehospital identification of stroke patients with large vessel occlusion (LVO). Goal: Assess the inter-rater agreement between a Vascular Neurologist and Alabama Trauma Communication Center (ATCC) personnel in diagnostic classification of stroke patients. Methods: The ATCC is staffed by paramedic-trained dispatchers who field calls from Emergency Medical Service (EMS) responders and maintain up-to-the-minute status of hospitals and resources 24/7. We trained ATCC personnel in stroke pathology, pathophysiology, appropriate patient selection for thrombolytic and endovascular therapies; and the previously derived 6 point Emergency Medical Stroke Assessment (EMSA). ATCC personnel guided EMS responders in the Birmingham Regional Emergency Medical Services System (BREMSS), and paged-out a hospital stroke prenotification that included specific EMSA scale items (gaze, facial droop, arm drift, leg drift, naming, and repetition). All interactions between the ATCC and EMS responders were recorded, allowing review of audio files and ongoing quality improvement. ATCC personnel and a vascular neurologist separately reviewed recordings and assigned scores to each patient according to the deficit stated by the EMS. To determine inter-rater reliability we utilized the Kappa statistic with a significance level of 0.05, and 95% confidence intervals (CI). Results: We sampled a total of 146 patients. We observed statistically significant agreement between the raters for all EMSA components, with 71% (CI=45-97%, p<0.0001) agreement in rating the gaze component, 54% (CI=26-82%, p=0.002) for the face, 57% (CI=29-85%, p=0.001) for the arm, 60% (CI=33-86%, p<0.0006) for the leg, 56% (CI=30-81%, p<0.001) for naming, and 34% (CI=6-61%, p<0.04) for repetition. Conclusion: We conclude that there is moderate to substantial agreement in most stroke assessment items by a paramedic staffed communication center and a vascular neurologist. There was only fair inter-rater agreement for repetition. Paramedic-trained dispatchers can reliably guide EMS responders and score the Emergency Medical Stroke Assessment.

An anatomical study of vascular communications between anterior tibial and peroneal osseosomes and its clinical application in proximal hemiarthroplasty of radiocarpal joint following tumor excision

There are speculations that the proximal third fibular osseosomes, supplied by the anterior tibial vessels cannot be reliably recruited on the peroneal vessels supplying fibular diaphyseal osseosomes. Anatomical study by the authors eschewed this speculation and paved way for an evidence-based surgery. Cadaveric dissection, dye injection, and radiological studies revealed existence of a reliable anastomotic musculoperiosteal vessel between these two osseosomes that could effectively recruit the proximal fibular osseosomes on the peroneal vessels. Also, operative tips and tricks for safeguarding these anastomotic vessels were defined by the cadaveric study. Aesthetic and functional outcomes were assessed in five clinical cases, where the fibular heads were harvested reliably on the peroneal pedicle and stable wrist joints were reconstructed following oncological excisions. Based on the evidence from the anatomical study, five clinical cases (three males and two females) affected by stage III GCT (giant cell tumor) of distal radius underwent microvascular fibular head hemiarthroplasty following tumor excision. Average follow-up of the patients was 18 months. At the end of follow-up period, all patients had an average MSTS (Musculoskeletal Tumor Society) score of 23. Scores ranged from 21 to 25. Patients had good functional outcomes with 69% average mobility in the reconstructed wrist when compared with the opposite normal wrist. Aesthesis of the reconstructed wrists were acceptable. The cadaveric study demonstrated concrete anatomical evidence of existence of an anastomotic musculoperiosteal vessel between anterior tibial and peroneal fibular osseosomes in all the specimens. Clinical study validated the safety of the vascularized proximal fibular hemiarthroplasty on peroneal pedicle. It may be a reliable method for reconstruction of the radiocarpal joint in the post-GCT distal radius excision with good aesthetic and functional outcomes. Level of Evidence: Level V, therapeutic study

Rumen-protected methionine in cattle: influences on reproduction, immune response, and productive performance

ABSTRACT: Nowadays, information and knowledge generated about the main ingredients used in cattle diets have enabled greater assertiveness in their formulation. Among the ingredients, amino acids stand out as a promising tool, capable of reducing total crude protein (CP) levels and adjusting optimal metabolizable protein concentrations in diets. Nutritional programs allow diets due to amino acid requirements, providing the opportunity to increase the efficiency of the use of dietary nitrogen, increasing the scarce protein concentrates, maintaining or even boosting performance. This review aimed to present the influences of methionine, in its formulation protected from ruminal degradation, according to reproductive parameters, immune response, and productive performance in cattle. Reproduction-related benefits are linked to the early days of embryonic implantation in the uterine environment, which initially secretes through the histotroph produced by endometrial glands, the nutrients needed to develop the conceptus until implantation, and vascular communication with the mother. Given the immune response, the main results are related to the benefits of innate immunity, with marked increase in phagocytic capacity of neutrophils and monocytes, as well as an important antioxidant effect mediated by methionine products, such as glutathione. When evaluating the influences on productivity, the most evident correlation is the increase in protein in the milk of cows supplemented with methionine. Over the past decade, studies investigating the potential benefits of this strategic supplementation in beef cattle were intensified, expanding the opportunities for the development of new experimental projects.

Chorionicity definition by ultrasound

Ultrasound is the main prenatal tool to diagnose chorionicity and amnionicity in multiple pregnancies. The importance of this differentiation lies on the fact that monochorionic (MC) pregnancies present with higher morbidity and mortality than dichorionic ones (DC), what can be explained by a sum of factors. Firstly, the placental vascular communications that are present in all MC pregnancies, which unbalance between fetal sides promote complications exclusive for this type of twins, such as twin-twin transfusion syndrome (TTTS), twin anemia–polycythemia sequence (TAPS) and twin reversed arterial perfusion sequence (TRAP). Secondly, monoamniotic (MA) pregnancies are also associated with other exclusive complications, such as intertwin cord entanglement and conjoined twins. Finally, adverse outcomes common to all multiple gestations are more prevalent in MC ones, probably because of unequal placental sharing, such as selective fetal growth restriction (SFGR), single fetal demise and congenital anomalies. Chorionicity and amnionicity should be ideally determined in the first trimester of pregnancy, when sensitivity approaches 100% by the identification of one or more of the following ultrasonographic criteria: two separate placentas (DC), absence of intertwin membrane (MC/MA), lambda (DC) or T sign (MC/DA) at intertwin membrane placental insertion. Other interamniotic membrane characteristics such thickness greater than 1.5 to 2 mm (DC) or counting the number of layers can be used, since DC membranes have 4 layers and MC only 2. After the first trimester, chorionicity and amnionicity determination becomes less sensible (approaching 90%), because identification of the previous features are impacted by fetal crowding, progressive thinning of membranes and lower prevalence of lambda sign with advancing gestational age. However, identification of discordant fetal sexes after the second trimester arises as a reliable marker of DC. Although these reported findings can be taken as general rules for the determination of chorioamnionicity, it's important to emphasize that in rare situations there are some pitfalls that can lead to incorrect diagnosis, such as oligohydramnios in one cavity misleading to a false MA diagnosis, discordant fetal sex in MC pregnancies due to genital malformation or sex chromosome abnormalities, bipartite MC placenta, false positive or negative lambda sign for various reasons. Concluding, providers must be aware of the importance of early chorioamnionicity determination and how to perform it reliably, since this diagnosis is the key to appropriate management of multiple pregnancies.

Tourniquet ALPPS: minimizing the risk of the first stage of ALPPS

Background: ALPPS is related with high morbidity and mortality, even after the first stage. The aim of this study is to present the results of a variant of the classic ALPPS known as ”tourniquet ALPPS” in an attempt to minimize the risk of the first surgery Methods: Our original “tourniquet ALPPS” consists of placing a tourniquet to occlude the vascular communications between both lobe instead of divide completely the liver parenchyma during the first stage. For the patients operated on with this approach we analyze operative and post-operative data of both interventions and volumetric data Results: Since September 2011 we performed 46 tourniquet ALPPS, the most frequent indication was colorectal liver metastases (31 cases, 64%). Median age was 61,7 (± 12,1). First stage: surgical time was 150 min (90-240), we didn’t use Pringle's maneuver in any case, median blood loss was 90 ml (40-900 ml) and only one patient needed blood transfusion (2,2%). Only 2 patients (4,3%) had severe complications(≥IIIB) and we performed 22 (47,8%) right trisectionectomy. The increase of the future liver remnant was 82,3% (±39,7) in 13 days (8-167 days). Second stage: surgical time was 175 minutes (90-360) and we performed 22 right trisectionectomy (52%). Median blood loss was 425 ml (80-1500) , 12 patients (26%) were transfused. Six patients (13%) had severe complications, and three of them died (6,5%) Conclusion: Tourniquet ALPPS obtains a fast hypertrophy with low rate of complications especially during the first stage

Stripped Mesenteric Flap: A Novel Option for Preventing Anastomotic Leakage in Circumferential Pharyngeal Reconstruction

Summary:Reconstruction of a circumferential pharyngeal defect with a free jejunal flap is a well-established procedure. However, anastomotic leakage often occurs, which can lead to abscess formation, pharyngocutaneous fistula formation, and carotid rupture. Previous reports have described covering the anastomotic site with a mesenteric flap to prevent anastomotic leakage. However, the mesentery is covered by a serosal membrane, which interferes with adhesion and vascular communication. Therefore, we stripped off the serosal membrane to accelerate adhesion to the anastomotic site. We retrospectively studied patients who had a history of radiotherapy and who had received a stripped mesenteric flap in a circumferential pharyngeal reconstruction procedure. We collected the following data: operative time, blood loss, postoperative complications, interval to resumption of oral intake, and duration of hospital stay. We obtained data for 11 patients. The jejunal flap failed in one patient because of arterial thrombosis. One of the other 10 patients developed anastomotic leakage caused by congested mucous membrane necrosis. The patient was treated conservatively and showed no clinical symptoms of infection or inflammation. The 9 remaining patients had no anastomotic leakage. In the present series, although anastomotic leakage was observed in one of 10 patients who underwent circumferential pharyngeal reconstruction using a stripped mesenteric flap, the severity of the leakage was minimized.

A Vanishing Heterogeneous Mass Arising From the Antrum: Ectopic Pancreatitis Masquerading as Malignancy

Ectopic pancreas, also known as pancreatic rest is defined as pancreatic tissue without vascular or anatomic communication with the main body of the pancreas. This case highlights the importance of a broad differential to abdominal pain and the work-up of a unique case of pancreatic rest masquerading as neoplasm and infection. A 32-year-old woman with a history only significant for B12 deficiency and travel to Singapore, Taiwan and Cuba who presented with gradually worsening epigastric discomfort, with transition to abdominal pain, nausea and vomiting. On admission, the patient was clinically stable, with vital signs of normal limits. Physical examination revealed tenderness to palpation and guarding in the right upper quadrant and epigastrum without peritoneal signs. Serum laboratory tests were significant for a leukocytosis (17.7x103 white cells per cubic millimeter) with a predominance of neutrophils (80%). Computerized tomography showed a 9.5cm complex, partially cystic mass at the gastroduodenal junction with thickened gastric wall and distorted 1st and 2nd portion of the duodenum. Endoscopic ultrasound with fine needle aspiration demonstrated a heterogeneous mass of 5 cm arising from the antrum, with normal appearance of the pancreas, and growth of mixed gram-positive flora. Duodenal perforation was suspected, she was started on antibiotics and offered surgical exploration, which she declined and presented to another hospital for a second opinion. Repeat CT showed improvement in the size of the mass with a 1cm cystic focus in the gastric antrum ([email protected]@@gure A). Post discharge, upper endoscopy, showed no fluid collection, mass or abscess where that had previously been a mass. However, a 12x9 mm heterogeneous lesion was seen arising from the second layer of the gastric wall in the antrum, consistent with pancreatic rest ([email protected]@@gure B). The patient was diagnosed with pancreatitis and a peri-pancreatic abscess occurring in the ectopic pancreatic tissue. The patient was discharged home with no further intervention. Infection or inflammation of ectopic tissues is an easily missed diagnosis that can lead to unnecessary malignancy work-up and surgery, as nearly occurred in this patient. Diagnosis is further made difficult because fine needle aspiration is superficial and results routinely show normal gastric biopsy, as was seen in our patient. Ectopic pancreas is an important consideration to prevent unnecessary work up and shorter hospitalization time for patients.1288_A.tif Figure 1: Computerized tomography of the abdomen showing improvement in the size of the original mass with a peripherally enhancing 2.1 cm fluid collection adjacent to the gastric antrum with mural thickening, as well as a 1 cm cystic focus in the gastric antrum.1288_B.tif Figure 2: Endoscopy with evidence of 12x9 mm heterogeneous round lesion arising from the second layer of the gastric wall in the antrum, consistent with pancreatic rest. The remainder of the pancreatic parenchyma was well seen without evidence of calcification, mass, chronic pancreatitis or any cystic lesion. Complete endoscopy showed no fluid collection, mass or abscess where there had previously been a large mass.

Ultrasound with Doppler evaluation of congenital hepatic vascular shunts.

Congenital aberrant hepatic vascular communications result from intrahepatic or extrahepatic errors in vascular development or involution during the transition from fetal to newborn hepatic circulation. These hepatic vascular shunts can be fortuitously discovered and asymptomatic, or can cause symptoms of varying severity, often presenting diagnostic dilemmas. Some hepatic vascular shunts resolve spontaneously while others require interventional radiologic or surgical closure. Affected patients are often first studied with real-time and Doppler ultrasound, so radiologists should familiarize themselves with the expected ultrasound findings of these vascular shunts for effective diagnosis, triage and management. In this review, the authors focus on ultrasound and Doppler findings of hepatic vascular shunts with underlying embryology, clinical features and management strategies. Broadly, these aberrant hepatic vascular communications include portosystemic venous shunts (which can be intra- or extrahepatic and include persistent patent ductus venosus), arterioportal, arteriovenous or mixed shunts.

Ileal blowout due to ileal atresia in a donor with twin-to-twin transfusion after fetoscopic laser surgery

Twin-to-twin transfusion syndrome (TTTS) occurs in 10% of monochorionic twin pregnancies, and can lead to a variety of complications due to imbalanced blood flow across placental vascular communications. In this report, we describe a case of intestinal injury in TTTS after fetoscopic laser ablation of the communicating vessels. Intestinal ischemic diseases have been reported in the recipient fetus after fetoscopic laser treatment in TTTS. In this report, we describe a unique case of ileal atresia in the donor twin. Keywords: atresia, blowout, fetoscopy, Ileal, laser, surgery, transfusion, twin to-twin

Association of Age-Related Hearing Loss With Cognitive Function, Cognitive Impairment, and Dementia

Epidemiologic research on the possible link between age-related hearing loss (ARHL) and cognitive decline and dementia has produced inconsistent results. Clarifying this association is of interest because ARHL may be a risk factor for outcomes of clinical dementia. To examine and estimate the association between ARHL and cognitive function, cognitive impairment, and dementia through a systematic review and meta-analysis. A search of PubMed, the Cochrane Library, EMBASE, and SCOPUS from inception to April 15, 2016, with cross-referencing of retrieved studies and personal files for potentially eligible studies was performed. Keywords included hearing, cognition, dementia, and Alzheimer disease. Cohort and cross-sectional studies published in peer-reviewed literature and using objective outcome measures were included. Case-control studies were excluded. One reviewer extracted and another verified data. Both reviewers independently assessed study quality. Estimates were pooled using random-effects meta-analysis. Subgroup and meta-regression analyses of study-level characteristics were performed. Hearing loss measured by pure-tone audiometry only and objective assessment measures of cognitive function, cognitive impairment, and dementia. Cognitive function outcomes were converted to correlation coefficients (r value); cognitive impairment and dementia outcomes, to odds ratios (ORs). Forty studies from 12 countries met our inclusion criteria. Of these, 36 unique studies with an estimated 20 264 unique participants were included in the meta-analyses. Based on the pooled maximally adjusted effect sizes using random-effects models, a small but significant association was found for ARHL within all domains of cognitive function. Among cross-sectional studies, a significant association was found for cognitive impairment (OR, 2.00; 95% CI, 1.39-2.89) and dementia (OR, 2.42; 95% CI, 1.24-4.72). Among prospective cohort studies, a significant association was found for cognitive impairment (OR, 1.22; 95% CI, 1.09-1.36) and dementia (OR, 1.28; 95% CI, 1.02-1.59) but not for Alzheimer disease (OR, 1.69; 95% CI, 0.72-4.00). In further analyses, study, demographic, audiometric, and analyses factors were associated with cognitive function. Vascular dysfunction and impaired verbal communication may contribute to the association between hearing loss and cognitive decline. Age-related hearing loss is a possible biomarker and modifiable risk factor for cognitive decline, cognitive impairment, and dementia. Additional research and randomized clinical trials are warranted to examine implications of treatment for cognition and to explore possible causal mechanisms underlying this relationship.

Recurrent Jejunal Intussusception From Heterotopic Pancreas

Introduction Heterotopic or ectopic pancreas is usually asymptomatic. We present a unique case of heterotopic pancreas of the jejunum causing recurrent jejunal intussusception. Case description A 39-year-old male presented locally with a one-year history of recurrent left mid abdominal discomfort. Prior contrast-enhanced computed tomography (Figure 1) was reviewed and showed two areas of jejunal intussusception (arrows). Subsequent diagnostic laparoscopy done at his local hospital was unrevealing. Given ongoing recurrent pain, he came for further evaluation. On examination at our institution, the patient did have pain to palpation in the left mid abdomen without an appreciated mass. Laboratory evaluation revealed a normal complete blood count, liver test and chromogranin A. Capsule endoscopy did visualize a submucosal jejunal lesion. Double balloon enteroscopy showed a 3-centimeter distal jejunal submucosal umbilicated mass (Figure 2). The biopsy of the lesion showed normal jejunal mucosa without dysplasia. Small bowel resection was recommended for definitive diagnosis and to treat the probable recurrent intussusception. Pathologically, a solid 1.2 x 0.8 x 0.6 cm submucosal mass was found. The biopsy result showed benign jejunum with pancreatic glands and ducts extending from the mucosal surface to the muscularis propria consistent with heterotopic pancreatic glands (Figure 3, HE, x10). He has had no further episode following the surgery.FigureFigureFigureDiscussion We present a rare case of heterotopic pancreas of the jejunum causing recurrent jejunal intussusception. Heterotopic (or ectopic) pancreas is a rare congenital anomaly defined as pancreatic tissue that lacks anatomical or vascular communication with the normal body of the pancreas. It is usually found in the stomach, duodenum and jejunum. It generally has a diameter of 1-4 cm and is commonly submucosal in nature. Heterotopic pancreas is commonly asymptomatic but can cause pancreatitis, abscess, pseudocyst, malignant transformation, or local complications such as obstruction or intussusception. The diagnosis of this lesion can be challenging. Endoscopic features include umbilication and duct opening, but these findings are non-specific. Endoscopic biopsies are generally superficial and not diagnostic. As the diagnosis is challenging, surgical or endoscopic excision is recommended for both diagnosis and treatment.

Endovascular Management of a Penetrating Zone III Retroperitoneal Gunshot Wound Injury; A Case Report

Traumatic iliac vessels injuries secondary to gunshot wound can often be fatal at the scene. One of the intriguing complications of vascular injuries is arteriovenous fistula. If the patient survives, these lesions may often not be diagnosed on first evaluation and patients may present with clinical signs and symptoms years later. Open surgical repair can have prohibitive morbidity and mortality and endovascular techniques, an effective treatment alternative, can interrupt the abnormal vascular communication and preserve artery vein patency. We describe a unique case of iliac arteriovenous fistula (AVF), secondary to a bullet injury, identified by imaging studies and subsequently treated with endovascular surgery. In conclusion, traumatic AVF are rare. Traditional teaching mandates that zone III pelvic retroperitoneal hematomas secondary to penetrating trauma be explored.

Acardiac Twin: A Report of Two Cases

AbstractMultiple gestations, especially monochorionic twins are associated with unique complications such as twin to twin transfusion syndrome (TTTS) and twin reversed arterial perfusion (TRAP) sequence due to preferential blood flow within the vascular communications between the two fetuses. TRAP sequence is a rare complication of monochorionic twins. The authors describe two cases of acardiac twins, one diagnosed at 17 weeks and the other at 24 weeks. While the first one was lost to follow-up, the second pregnancy was managed expectantly with close antepartum surveillance and had a term vaginal delivery of a healthy baby, along with the acardiac twin which was non-viable. The pump twin continues to be developmentally normal.

Modulation of Local and Systemic Heterocellular Communication by Mechanical Forces: A Role of Endothelial Nitric Oxide Synthase.

Significance: In this review, we discuss the role of nitric oxide (NO) as a key physiological mechanotransducer modulating both local and systemic heterocellular communication and contributing to the integrated (patho)physiology of the cardiovascular system. A deeper understanding of mechanotransduction-mediated local and systemic nodes controlling heterocellular communication between the endothelium, blood cells, and other cell types (e.g., cardiomyocytes) may suggest novel therapeutic strategies for endothelial dysfunction and cardiovascular disease.Recent Advances: Mechanical forces acting on mechanoreceptors on endothelial cells activate the endothelial NO synthase (eNOS) to produce NO. NO participates in (i) abluminal heterocellular communication, inducing vasorelaxation, and thereby regulating vascular tone and blood pressure; (ii) luminal heterocellular communication, inhibiting platelet aggregation, and controlling hemostasis; and (iii) systemic heterocellular communication, contributing to adaptive physiological processes in response to exercise and remote ischemic preconditioning. Interestingly, shear-induced eNOS-dependent activation of vascular heterocellular communication constitutes the molecular basis of all methods applied in the clinical routine for evaluation of endothelial function.Critical Issues and Future Directions: The integrated physiology of heterocellular communication is still not fully understood. Dedicated experimental models are needed to analyze messengers and mechanisms underpinning heterocellular communication in response to physical forces in the cardiovascular system (and elsewhere). Antioxid. Redox Signal. 26, 917–935.

Case report. Multiple Mediastinal Arteriovenous Fistulas in a Patient with Myocardial Ischemia Symptoms and Tachy-Brady Arrhythmias

Abstract Arteriovenous fistulas are abnormal vascular communications between the arterial and venous system and may lead to the development of arteriovenous shunts. These malformations are extremely rare, and their diagnosis can be difficult due to the lack of symptoms or the absence of hemodynamic consequences. In many cases, arteriovenous fistulas are discovered by chance. In this brief report, we present the case of a 31-year-old male with symptoms suggestive of angina pectoris, tachycardia-bradycardia syndrome and multiple episodes of syncope. Multi-slice computed tomography revealed the presence of multiple mediastinal fistulas connecting the aorta, superior vena cava, pulmonary veins and azygos system.

Mechanisms regulating angiogenesis underlie seasonal control of pituitary function

Seasonal changes in mammalian physiology, such as those affecting reproduction, hibernation, and metabolism, are controlled by pituitary hormones released in response to annual environmental changes. In temperate zones, the primary environmental cue driving seasonal reproductive cycles is the change in day length (i.e., photoperiod), encoded by the pattern of melatonin secretion from the pineal gland. However, although reproduction relies on hypothalamic gonadotrophin-releasing hormone output, and most cells producing reproductive hormones are in the pars distalis (PD) of the pituitary, melatonin receptors are localized in the pars tuberalis (PT), a physically and functionally separate part of the gland. How melatonin in the PT controls the PD is not understood. Here we show that melatonin time-dependently acts on its receptors in the PT to alter splicing of vascular endothelial growth factor (VEGF). Outside the breeding season (BS), angiogenic VEGF-A stimulates vessel growth in the infundibulum, aiding vascular communication among the PT, PD, and brain. This also acts on VEGF receptor 2 (VEGFR2) expressed in PD prolactin-producing cells known to impair gonadotrophin secretion. In contrast, in the BS, melatonin releases antiangiogenic VEGF-Axxxb from the PT, inhibiting infundibular angiogenesis and diminishing lactotroph (LT) VEGFR2 expression, lifting reproductive axis repression in response to shorter day lengths. The time-dependent, melatonin-induced differential expression of VEGF-A isoforms culminates in alterations in gonadotroph function opposite to those of LTs, with up-regulation and down-regulation of gonadotrophin gene expression during the breeding and nonbreeding seasons, respectively. These results provide a mechanism by which melatonin can control pituitary function in a seasonal manner.