Candida albicans extracellular vesicles trigger type I IFN signalling via cGAS and STING

The host type I interferon (IFN) pathway is a major signature of inflammation induced by the human fungal pathogen, Candida albicans. However, the molecular mechanism for activating this pathway in the host defence against C. albicans remains unknown. Here we reveal that mice lacking cyclic GMP-AMP synthase (cGAS)-stimulator of IFN genes (STING) pathway components had improved survival following an intravenous challenge by C. albicans. Biofilm-associated C. albicans DNA packaged in extracellular vesicles triggers the cGAS-STING pathway as determined by induction of interferon-stimulated genes, IFNβ production, and phosphorylation of IFN regulatory factor 3 and TANK-binding kinase 1. Extracellular vesicle-induced activation of type I IFNs was independent of the Dectin-1/Card9 pathway and did not require toll-like receptor 9. Single nucleotide polymorphisms in cGAS and STING potently altered inflammatory cytokine production in human monocytes challenged by C. albicans. These studies provide insights into the early innate immune response induced by a clinically significant fungal pathogen.

Cross-kingdom anti-inflammatory effects of fungal melanin on airway epithelium by post-translational blockade of chemokine secretion

Respiratory infections caused by the human fungal pathogens, Aspergillus fumigatus and Cryptococcus neoformans, are a major cause of mortality for immunocompromised patients. Exposure to these pathogens occurs through inhalation, although the role of the respiratory epithelium in disease pathogenesis has not been defined. Employing a primary human airway epithelial model, we demonstrate that fungal melanins potently block the post-translational secretion of CXCL1 and CXCL8 independent of transcription or the requirement of melanin to be phagocytosed, leading to a significant reduction of neutrophils to the apical airway both in vitro and in vivo. Aspergillus-derived melanin, a major constituent of the fungal cell wall, has far-reaching effects, dampening airway epithelial chemokine production in response to fungi, bacteria, and exogenous cytokines. Taken together, our results reveal a critical role for melanin interaction with airway epithelium in shaping the host response to fungal and bacterial pathogens.

The C-Type Lectin Receptor Dectin-2 Is a Receptor for Aspergillus fumigatus Galactomannan

Aspergillus fumigatus is a ubiquitous environmental mold that causes significant mortality particularly among immunocompromised patients. The detection of the Aspergillus-derived carbohydrate galactomannan in patient serum and bronchoalveolar lavage fluid is the major biomarker used to detect A. fumigatus infection in clinical medicine. Despite the clinical relevance of this carbohydrate, we lack a fundamental understanding of how galactomannan is recognized by the immune system and its consequences. Galactomannan is composed of a linear mannan backbone with galactofuranose sidechains and is found both attached to the cell surface of Aspergillus and as a soluble carbohydrate in the extracellular milieu. In this study, we utilized fungal-like particles composed of highly purified Aspergillus galactomannan to identify a C-type lectin host receptor for this fungal carbohydrate. We identified a novel and specific interaction between Aspergillus galactomannan and the C-type lectin receptor Dectin-2. We demonstrate that galactomannan bound to Dectin-2 and induced Dectin-2-dependent signaling, including activation of spleen tyrosine kinase, gene transcription, and tumor necrosis factor alpha (TNF-α) production. Deficiency of Dectin-2 increased immune cell recruitment to the lungs but was dispensable for survival in a mouse model of pulmonary aspergillosis. Our results identify a novel interaction between galactomannan and Dectin-2 and demonstrate that Dectin-2 is a receptor for galactomannan, which leads to a proinflammatory immune response in the lung. IMPORTANCE Aspergillus fumigatus is a fungal pathogen that causes serious and often fatal disease in humans. The surface of Aspergillus is composed of complex sugar molecules. Recognition of these carbohydrates by immune cells by carbohydrate lectin receptors can lead to clearance of the infection or, in some cases, benefit the fungus by dampening the host response. Galactomannan is a carbohydrate that is part of the cell surface of Aspergillus but is also released during infection and is found in patient lungs as well as their bloodstreams. The significance of our research is that we have identified Dectin-2 as a mammalian immune cell receptor that recognizes, binds, and signals in response to galactomannan. These results enhance our understanding of how this carbohydrate interacts with the immune system at the site of infection and will lead to broader understanding of how release of galactomannan by Aspergillus effects the immune response in infected patients.

An anatomical study of the superficial inferior epigastric vessels in humans

The lower abdominal skin and fat has become a standard for breast reconstruction in terms of skin texture, suppleness and colour. Concerns regarding donor site morbidity related to the harvest of rectus abdominis musculocutaneous flap, based on the deep inferior epigastric vessels, have turned attention towards alternative options. The superficial inferior epigastric artery (SIEA) flap is a fasciocutaneous flap that has been used for reconstruction of the breast, as well as head, neck and limb defects. In Taylor's classic dissection series the SIEA was 'absent' in 35% [Plast Reconstr Surg 56 (1975) 243]. In our series of 22 cadaver dissections (eight female, three male) the SIEA was identified in 20 and the vein (SIEV) in 21. In 15, the artery was located at the level of the inguinal ligament, within 1 cm of its midpoint. In 17, the origin, from the common femoral artery, was within 2 cm of the inguinal ligament. In 18, the SIEA arose as a common trunk with the superficial circumflex iliac artery, superficial external pudendal artery, and/or the deep circumflex iliac artery. Mean SIEA calibre was 1.9 mm and the mean pedicle length from origin to inguinal ligament was 5.2 cm. Our findings suggest that the SIEA is more consistently present and larger in calibre than previously reported, and consequently may be of greater clinical use than previously believed.

The surface anatomy of the germinal matrix of the nail bed in the finger

Nail spicules result from incomplete excision of the nail matrix of the finger. We report a histological study to delineate the surface anatomy of the nail matrix. Sections were cut longitudinally and transversely in 19 fingertips. The proximal midline extent of the nail matrix was measured and expressed as a ratio of the distance from the nail fold to the distal interphalangeal joint. In the lateral sections, the angle subtended between the midline vertical and the lateral extent of the nail matrix was measured. The mean ratio of the proximal extent was 0.55 in the midline and the lateral angular extent was 66 degrees. The authors recommend that excision of the nail matrix should be rectangular, extending to the midlateral lines and proximally to a point three-quarters of the distance from the nail fold to the distal interphalangeal joint crease.

Ovarian cancer mimicking recurrence at colorectal anastomosis: report of a case

PURPOSE

The aim of this article is to emphasize the increased risk of developing metachronous ovarian tumors after resection of rectal cancer.

METHOD AND RESULTS

We report the case of a postmenopausal female patient who, five years after anterior resection, developed a primary ovarian malignancy that invaded a rectal anastomosis and in so doing mimicked a recurrence of a Dukes A rectal cancer. To our knowledge, such an occurrence has not been described previously in the literature.

CONCLUSION

This case illustrates the possible benefits of routine prophylactic oophorectomy at the time of colorectal cancer resection.

Methicillin-resistant Staphylococcus aureus in burns patients--why all the fuss?

Procedures designed to limit spread of methicillin-resistant Staphylococcus aureus (MRSA) in burns units demand time and resources. To assess the significance of MRSA in burns patients we performed a retrospective review of MRSA colonization in in-patients over a 41-month period at the North Trent Sub-regional Burns Unit. Patients were compared with MRSA free controls, matched for age and percentage body surface area (BSA) burn and admitted during the same time period. Length of stay, number of operations and deaths were outcome indicators. All patients managed non-operatively were excluded, leaving 40 MRSA patients and 46 controls. There was no statistical difference between the two groups with regard to number of operations (p= 0.07), duration of admission (p = 0.12) or mortality (p = 0.09). Of the control group, 83% had wound swabs positive for methicillin-sensitive Staphylococcus aureus (MSSA). there was no statistical difference in any outcome variables between this sub-group of controls and MRSA patients. Colonization with S. aureus (both MRSA and MSSA) was associated with larger burns (p<0.05), twice as many operative procedures (p<0.05) and prolonged admissions (p<0.01). Mortality was unaltered by staphylococcal colonization (p = 0.8). Although our study lacks power, we would suggest that methicillin resistance per se is not associated with increased morbidity or mortality in burns patients.

Bilateral spontaneous rupture of flexor digitorum profundus tendons

Spontaneous tendon rupture is an unusual condition usually associated with underlying disease processes such as rheumatoid arthritis, chronic renal failure or bony abnormalities of the hand. We report a case of spontaneous, non-concurrent bilateral rupture of flexor profundus tendons in an otherwise healthy individual. Treatment was successful and consisted of a two-stage reconstruction of the ruptured tendon.

Selective endoscopy in management of ingested foreign bodies of the upper gastrointestinal tract: is it safe?

During a four-year period, 308 patients presented following ingestion of foreign bodies. Ingestion was accidental in 272 cases (88.3%) and deliberate in the remainder. Symptoms at presentation included dysphagia, odynophagia, nausea and vomiting, chest pain and pharyngeal discomfort. Sixty-eight patients were asymptomatic. A policy of expectant management and selective endoscopy was employed. Following initial assessment 202 patients (65.6%) were discharged without treatment, 30 (9.7%) of whom were later reviewed as outpatients and did not require admission. Forty-nine patients (16%) were admitted for treatment; 27 had oesophagoscopy, five bronchoscopy and two had foreign body extraction with direct laryngoscopy. In nine patients who were endoscoped, no foreign body was identified. Twenty-seven others were referred to the otorhinolaryngology service in another hospital. There were no deaths in the group and morbidity was 1.2%. We conclude that a policy of selective endoscopy is safe and effective in the management of patients following ingestion of foreign bodies.

Deliberate ingestion of foreign bodies by institutionalised psychiatric hospital patients and prison inmates

Deliberate and recurrent foreign body ingestion is a common problem among institutionalised patients. We review our experience with 36 cases of deliberate foreign body ingestion by prisoners or psychiatric patients, thirty of whom were institutionalised at the time of ingestion. Symptoms were frequently severe in the prison inmate group but, in contrast, psychiatric patients presented with few, if any, symptoms. A majority of objects pass spontaneously or remain in situ without complication. Twenty-four patients were discharged following initial evaluation and without specific treatment. Eight of these were reviewed electively and discharged within one week. Twelve patients were admitted for observation, seven of whom were discharged within 48 hrs. Upper gastrointestinal endoscopy was performed in four patients and an intragastric foreign body identified in two cases. Laparotomy was performed in two cases for unresolving mechanical intestinal obstruction. Management should be conservative when possible, with surgery indicated only for complications.

"How safe is splenectomy?"

The increased risk of sepsis in patients following splenectomy has been well documented. Fear of overwhelming post-splenectomy sepsis (OPSI) has resulted in a generalized trend towards splenic salvage among surgeons. However, splenorrhaphy and attempts at splenic salvage may of themselves predispose to significant morbidity, sometimes more serious than increased susceptibility to infection associated with splenectomy. This study aims to assess the risk of splenectomy and subsequent asplenia. We reviewed 246 patients who underwent splenectomy over a 16 year period. Indications for splenectomy were considered under the following headings: haematological (N = 116), trauma (N = 69), visceral carcinoma (N = 28), incidental (N = 13) and miscellaneous (N = 20). There were 28 deaths in the series, primarily among those in the intra-abdominal carcinoma (13) and multiple trauma (13) groups. Two deaths were recorded among patients undergoing elective splenectomy for benign disease. Thrombo-embolic complications were recorded in nine patients; respiratory tract infection in 36 patients and intra-abdominal abscess in two patients. Two cases of post-splenectomy pneumococcal septicaemia were documented, neither of which was fatal. While not an entirely benign procedure, splenectomy can be performed relatively safely, especially when performed for benign disease in an adult population.