Imaging diagnosis and differential diagnosis of extraskeletal osteosarcoma.

OBJECTIVE: The aim of this study was to investigate the clinical, imaging and pathological features of extraskeletal osteosarcoma (EOS) and to improve the understanding of this disease and other similar lesions. METHODS: The data for 11 patients with pathologically confirmed extraosseous osteosarcoma, including tumour site and size and imaging and clinical manifestations, were analysed retrospectively. RESULTS: Six patients were male (60%), and 5 were female (40%); patient age ranged from 23 to 76 years (average age 47.1 years). Among the 11 patients, 7 had clear calcifications or ossification with different morphologies, and 2 patients showed a massive mature bone tumour. MRI showed a mixed-signal mass with slightly longer T1 and T2 signals in the tumour parenchyma. Enhanced CT and MRI scans showed enhancement in the parenchyma. Ten patients had different degrees of necrosis and cystic degeneration in the mass, 2 of whom were complicated with haemorrhage, and MRI showed "fluid‒fluid level" signs. Of the 11 patients, five patients survived after surgery, and no obvious recurrence or metastasis was found on imaging examination. One patient died of lung metastasis after surgery, and 2 patients with open biopsy died of disease progression. One patient died of respiratory failure 2 months after operation. 2 patients had positive surgical margins, and 1 had lung metastasis 6 months after operation and died 19 months after operation. Another patient had recurrence 2 months after surgery. CONCLUSION: The diagnosis of EOS requires a combination of clinical, imaging and histological examinations. Cystic degeneration and necrosis; mineralization is common, especially thick and lumpy mineralization. Extended resection is still the first choice for localized lesions. For patients with positive surgical margins or metastases, adjuvant chemoradiotherapy is needed.

Differential Diagnosis of Intracranial Malignant Tumors Using MRI Based on Morphological Features and Signal Intensity Ratio of Lesions.

Objective: To investigate the clinical value of conventional MRI morphological features and signal intensity ratio in the differential diagnosis of intracranial malignant tumors (high-grade glioma (HGG), primary central nervous system Lymphoma (PCNSL) and single brain metastasis (BM). Methods: Retrospective analysis of 92 cases of HGG, 27 cases of PCNSL, and 35 cases of BM. MRI data in The General Hospital of Western Theater Command from August 2014 to December 2021, comparative analysis of morphological characteristics of tumors and lesion/normal brain parenchyma signal ratio (lesiontonormal parenchymaratio, LNR), five indexes were included T1WI signal ratio (LNRT1), T2WI signal intensity ratio (LNRT2), T2WI/T1WI signal ratio (LNRT2/T1), T1WI enhanced signal ratio (LNRT1CE) and contrast enhancement ratio (CER). The differential diagnostic performance was also assessed by subject operating characteristic (ROC) curves. Results: HGG, PCNSL, and BM were all seen more frequently in the supratentorial region, More than 50% of HGG mainly showed irregular morphology, intratumoral necrosis, cystic degeneration, peritumoral severe edema, cyclic uneven enhancement after enhancement, PCNSL significantly enhanced the main uniformity, necrosis cyst became rare, BM group showed uneven enhancement, no obvious specificity, and the differences in tumor morphology, peritumor edema, intratumor hemorrhage, necrotic cystic lesions, and enhancement patterns were statistically significant among the three (P < .05). PCNSL LNRT1 and its LNRT1CE (LNRT1: 0.558 ± 0.050, LNRT1CE: 1.637 ± 0.125) were significantly higher than those of HGG (LNRT1: 0.480 ± 0.077, LNRT1CE: 1.425 ± 0.160) and BM (LNRT1: 0.514 ± 0.120, LNRT1CE: 1.375 ± 0.122), while LNRT2 and LNRT2/T1 (LNRT2: 1.389 ± 0.086, LNRT2/T1: 2.511 ± 0.295) were significantly lower than those of HGG (LNRT2: 1.527 ± 0.191, LNRT2/T1: 3.263 ± 0.657), and BM (LNRT2: 1.504 ± 0.089, LNRT2/T1: 3.103 ± 0.830). There was no significant difference in CER among the three groups (P > .05). ROC curve analysis of LNRT1, LNRT2, LNRT1CE, and LNRT2/T1 could be used to discriminate PCNSL from HGG and BM, with LNRT1CE having the largest area under the curve of 0.873, sensitivity of 0.963 and specificity of 0.669. Conclusion: MRI lesion morphological features and signal intensity ratio are important for discriminating HGG from PCNSL and BM. As a quantitative parameter, tumor signal intensity ratio can provide an important supplement for subjective judgment, to improve the accuracy of tumor qualitative diagnosis and differential diagnosis.

Vaginal necrosis: A rare late toxicity after radiation therapy.

Vaginal necrosis is a late radiation tissue injury with serious morbidity complications. It is rare, and its incidence is not well assessed in prospective trials. Patient comorbidities and radiation dose can significantly increase the risk. As treatment of gynecologic malignancies often involve a multidisciplinary approach, timely diagnosis and appropriate management by physicians of the team are crucial. Untreated vaginal necrosis can lead to infection, hemorrhage, necrosis-related fistulation to the bladder or rectum, perforation, and death. In this review, we describe the pathophysiology of vaginal necrosis, its clinical course, and management options.

MYONECROSIS AND DEATH DUE TO PRESUMED MICROCYSTIN TOXICOSIS IN AMERICAN WHITE PELICANS (PELECANUS ERYTHRORHYNCOS).

Over a period of 5 mo, seven out of eight American white pelicans (Pelecanus erythrorhynchos) housed on a spring-fed pond at a zoo died or were euthanized. Clinical signs included inability to stand, anorexia, and weight loss. Clinicopathologic findings included heterophilic leukocytosis and elevated creatine kinase and aspartate aminotransferase. Histopathologic findings on all pelicans demonstrated severe, chronic, diffuse rhabdomyofiber degeneration and necrosis, making vitamin E deficiency a differential diagnosis despite routine supplementation. Based on tissue and pond water assays for the cyanobacterial toxin, microcystin, toxicosis is suspected as the inciting cause of death in these cases. We hypothesize that vitamin E exhaustion and resultant rhabdomyodegeneration and cardiomyopathy were sequelae to this toxicosis.

Coagulative necrotic pituitary adenoma apoplexy: A retrospective study of 21 cases from a large pituitary center in China.

PURPOSE: Coagulative necrotic pituitary apoplexy (CNPA) is a clinical entity with unique intraoperative and histopathological manifestations. We aimed to improve the knowledge of this rare disease through the largest case series published to date. METHODS: A retrospective review of 21 CNPA patients was performed from among 5095 patients who underwent surgery for pituitary adenomas at a single institution between January 2009 and June 2017. The demographic, clinical, endocrine, neuroimaging, intraoperative, and histopathological findings, management and prognosis were summarized. RESULTS: Headache was the most common symptom that was observed in 21 patients, followed by visual disturbances (17/21, 81.0%), nausea and vomiting (16/21, 76.2%), electrolyte disturbance (13/21, 61.9%), and oculomotor palsies (10/21, 47.6%). Hypopituitarism with at least one anterior pituitary deficiency, especially panhypopituitarism (10/21, 47.6%), was present in 81.0% of patients. Most patients (81.0%) showed typical MRI appearances. All 21 patients underwent transsphenoidal surgery (TSS), and 16 patients had total tumor resection demonstrated by postoperative MRI. Cottage cheese-like necrosis was observed in 16 patients (76.2%) intraoperatively. Histopathology showed large areas of pink, acellular, coagulative necrotic areas in the central zone, and a pseudocapsule in the border zone. After follow-up for 4.3 ± 2.3 years, only 28.6% of patients still suffered from corticotropic deficiency, and 9.5% of patients had gonadotropic deficiency. These patients were administered the appropriate corresponding hormones for life. CONCLUSIONS: CNPA can be correctly diagnosed preoperatively by typical clinical and MRI characteristics. Early surgery combined with hyperbaric oxygen therapy early postoperatively usually yields satisfactory endocrine and neuro-ophthalmic outcomes.

Computed tomography and histopathological findings after embolization with inherently radiopaque 40µm-microspheres, standard 40µm-microspheres and iodized oil in a porcine liver model.

PURPOSE: The present study compared standard computed tomography (CT) and histopathological findings after endovascular embolization using a prototype of inherently radiopaque 40µm-microspheres with both standard 40µm-microspheres and iodized oil in a porcine liver model. MATERIALS AND METHODS: Twelve pigs were divided into six study groups, of two pigs each. Four pigs were embolized with iodized oil alone and four with radiopaque microspheres; two animals in each group were sacrificed at 2 hours and two at 7 days. Two pigs were embolized with radiopaque microspheres and heparin and sacrificed at 7 days. Two pigs were embolized with standard microspheres and sacrificed at 2 hours. CT was performed before and after segmental embolization and before sacrifice at 7 days. The distribution of embolic agent, inflammatory response and tissue necrosis were assessed histopathologically. RESULTS: Radiopaque microspheres and iodized oil were visible on standard CT 2 hours and 7 days after embolization, showing qualitatively comparable arterial and parenchymal enhancement. Quantitatively, the enhancement was more intense for iodized oil. Standard microspheres, delivered without contrast, were not visible by imaging. Radiopaque and standard microspheres similarly occluded subsegmental and interlobular arteries and, to a lesser extent, sinusoids. Iodized oil resulted in the deepest penetration into sinusoids. Necrosis was always observed after embolization with microspheres, but never after embolization with iodized oil. The inflammatory response was mild to moderate for microspheres and moderate to severe for iodized oil. CONCLUSION: Radiopaque 40µm-microspheres are visible on standard CT with qualitatively similar but quantitatively less intense enhancement compared to iodized oil, and with a tendency towards less of an inflammatory reaction than iodized oil. These microspheres also result in tissue necrosis, which was not observed after embolization with iodized oil. Both radiopaque and standard 40µm-microspheres are found within subsegmental and interlobar arteries, as well as in hepatic sinusoids.

Ischemic necrosis of the digits and hyperlipidemia associated with atherosclerosis in a Miniature American Shepherd.

CASE DESCRIPTION A 2.5-year-old 12-kg (26.4-lb) castrated male Miniature American Shepherd was referred because of a 3-week history of a localized crusted skin lesion on the digital pad of digit 3 of the right hind limb. CLINICAL FINDINGS Skin lesions were noted on the digital pads of the right hind limb. Serum biochemical analyses indicated severe hypercholesterolemia and hypertriglyceridemia. Ultrasonography of the terminal portion of the aorta and other major arterial vessels revealed substantial arteriosclerotic change. TREATMENT AND OUTCOME Medical treatments included administration of atorvastatin calcium, a low-fat diet, and omega-3 fatty acids to reduce serum lipids concentration; clopidogrel to prevent thrombosis; pentoxifylline to improve microcirculatory blood flow; clomipramine hydrochloride and trazodone hydrochloride to help with the behavioral problems; and gabapentin to help with pain management and behavioral problems. Surgical management included amputation of the initial digit involved, then eventually the entire initial limb involved. The response to treatment was poor, and euthanasia was elected. Postmortem findings revealed severe, widespread, and chronic intimal atherosclerosis; mild, widespread, and degenerative changes in the cerebral cortex; and edema and vascular congestion in the meninges. CLINICAL RELEVANCE To the authors' knowledge, this was the first report of skin necrosis secondary to atherosclerosis in a dog. Although the incidence of atherosclerosis has been considered very low in dogs, it should be investigated in dogs with severe hyperlipidemia. Primary hyperlipidemia has not been previously described in Miniature American Shepherd dogs but was the suspected underlying metabolic disorder.

Necrotizing otitis externa: diagnosis, treatment, and outcome in a case series.

We reviewed 25 cases of patients diagnosed with necrotizing otitis externa in our tertiary university-affiliated medical center between 2009 and 2015. Mean overall hospitalization duration was 14.52days, 95% of the patients showed specific seasonal incidence. Mean duration of symptoms prior to hospitalization was 6weeks and the duration correlated with outcome. Only 8% of the patients presented with cranial neuropathies; however, this presentation correlated with adverse outcome. Pseudomonas aeruginosa was the main causative organism (50%), with a 30% multidrug-resistance rate. A high rate (35%) of fungal pathogens was noted. Seventeen patients (68%) were eventually operated; however, only 5 patients needed extensive surgery under general anesthesia. Computed tomography (CT) evidence of adjacent structures' involvement correlated with adverse outcome. Eighty percent of our patients improved clinically. The overall death rate was 12% and the disease-related mortality rate was 8%. Our findings state the importance of limited surgical intervention and microbiologic cultures in disease treatment. This is particularly important in patients with cranial neuropathies and CT finding of adjacent structural involvement that correlate with adverse prognosis. A rising pseudomonal antibiotic resistance and fungal infections may challenge antibiotic treatment in the future.

Necrosis cerebral por radiación: desafío diagnóstico y tratamiento clínico / Cerebral radiation necrosis: diagnostic challenge and clinical management

La radioterapia cerebral es una de las piedras angulares del tratamiento de numerosos tumores cerebrales primarios y metastásicos. Pese a ello, aparte de su efecto terapéutico deseado sobre las células tumorales, una parte sustancial de los pacientes sufre efectos secundarios de carácter neurotóxico a consecuencia de su aplicación. La necrosis por radiación puede provocar síntomas neurológicos y cambios radiográficos progresivos. Diferenciarla de la progresión tumoral en las imágenes puede llegar a ser un verdadero reto, dada la similitud que en ocasiones presentan las características de la resonancia magnética en ambas situaciones. Por esa razón, a veces es necesario recurrir a la biopsia quirúrgica y la confirmación histopatológica para confirmar el diagnóstico y orientar el tratamiento. Existen opciones eficaces de tratamiento para la necrosis cerebral por radiación y los pacientes con síntomas deben recibirlas. Es preciso ampliar el conocimiento sobre los procesos celulares y moleculares que se esconden detrás del desarrollo de la necrosis por radiación si se quiere prevenir y minimizar la morbilidad asociada a ella y mejorar las estrategias terapéuticas disponibles (AU)

Cerebral radiation is an indispensable cornerstone in the treatment of many primary and metastatic brain tumors. However, besides its desired therapeutic effect on tumor cells, a significant proportion of patients will experience neurotoxic side effects as the consequence of radiotherapy. Radiation necrosis can result in progressive neurological symptoms and radiographic changes. To differentiate radiation necrosis from progressive tumor based on imaging can pose a diagnostic challenge because the MRI characteristics may be similar in both situations. Therefore, surgical biopsy and pathological confirmation is sometimes necessary to guide further management. Effective treatment options for cerebral radiation necrosis exist and should be offered to symptomatic patients. A better understanding of the cellular and molecular processes underlying the development of radiation necrosis is necessary to prevent and minimize radiationassociated morbidity and to improve treatment strategies (AU)

[Necrotising soft-tissue infections: diagnostics and treatment]. / Necrotiserende wekedeleninfecties: diagnostiek en behandeling.

Necrotising soft-tissue infections occur in the soft tissue compartment consisting of the dermis, subcutaneous tissue, superficial fascia (fascia of Scarpa), deep fascia and muscle. Although this severe and acutely life-threatening infection has a low incidence, both GPs and specialists will see a necrotizing soft-tissue infection more than once during their career. The mortality related to necrotising soft-tissue infections has been halved during the past 15 years from nearly 40 to 20% due to adequate treatment. Laboratory examination and X-ray findings could be of added value, but the gold standard remains biopsy of the fascia and Gram staining. Treatment consists of prompt volume resuscitation in case of sepsis, administration of broad spectrum antibiotics and surgical debridement; this debridement should be as skin-sparing as possible. The use of hyperbaric oxygen therapy has remained a controversial issue, unless a patient has gas gangrene, caused by Clostridium species. A multidisciplinary treatment and admission to a tertiary intensive care unit are indispensable for the treatment of a septic patient with necrotizing soft-tissue infection.

Propolis-induced descending necrotizing mediastinitis and aspiration pneumonia.

Propolis is a resinous substance collected by bees as a sealant for their hives. It is also used in traditional medicine as an antioxidant and antiinflammatory agent to treat ulcers, superficial burns, and microbial diseases. In this report, a 40-year-old woman who took liquid propolis for relief of her common cold experienced severe sore throat, dysphagia, and easy choking followed by fever and chills. Descending necrotizing mediastinitis and concomitant aspiration pneumonia were evident on the image studies. We performed video-assisted thoracoscopic surgery to achieve immediate and adequate drainage, and the patient resumed normal deglutition 2 months later. Early diagnosis and prompt video-assisted thoracoscopic surgery intervention are paramount to manage this life-threatening situation.

Cerebral radiation necrosis: a review of the pathobiology, diagnosis and management considerations.

Radiation therapy forms one of the building blocks of the multi-disciplinary management of patients with brain tumors. Improved survival following radiation therapy may come with a cost, including the potential complication of radiation necrosis. Radiation necrosis impacts the quality of life in cancer survivors, and it is essential to detect and effectively treat this entity as early as possible. Significant progress in neuro-radiology and molecular pathology facilitate more straightforward diagnosis and characterization of cerebral radiation necrosis. Several therapeutic interventions, both medical and surgical, may halt the progression of radiation necrosis and diminish or abrogate its clinical manifestations, but there are still no definitive guidelines to follow explicitly that guide treatment of radiation necrosis. We discuss the pathobiology, clinical features, diagnosis, available treatment modalities, and outcomes in the management of patients with intracranial radiation necrosis that follows radiation used to treat brain tumors.

Real-time monitoring of in vivo acute necrotic cancer cell death induced by near infrared photoimmunotherapy using fluorescence lifetime imaging.

A new type of monoclonal antibody (mAb)-based, highly specific phototherapy (photoimmunotherapy; PIT) that uses a near infrared (NIR) phthalocyanine dye, IRDye700DX (IR700) conjugated with a mAb, has recently been described. NIR light exposure leads to immediate, target-selective necrotic cell death in vitro. Detecting immediate in vivo cell death is more difficult because it takes at least 3 days for the tumor to begin to shrink in size. In this study, fluorescence lifetime (FLT) was evaluated before and after PIT for monitoring the immediate cytotoxic effects of NIR mediated mAb-IR700 PIT. Anti-epidermal growth factor receptor (EGFR) panitumumab-IR700 was used for targeting EGFR-expressing A431 tumor cells. PIT with various doses of NIR light was conducted in cell pellets in vitro and in subcutaneously xenografted tumors in mice in vivo. FLT measurements were obtained before and 0, 6, 24, and 48 hours after PIT. In vitro, PIT at higher doses of NIR light immediately led to FLT shortening in A431 cells. In vivo PIT induced immediate shortening of FLT in treated tumors after a threshold NIR dose of 30 J/cm(2) or greater. In contrast, lower levels of NIR light (10 J/cm(2) or smaller) did not induce shortening of FLT. Prolongation of FLT in tissue surrounding the tumor site was noted 6 hours after PIT, likely reflecting phagocytosis by macrophages. In conclusion, FLT imaging can be used to monitor the acute cytotoxic effects of mAb-IR700-induced PIT even before morphological changes can be seen in the targeted tumors.

Optimised diagnosis and treatment of necrotizing external otitis is warranted.

INTRODUCTION: Necrotizing external otitis (NEO) is a devastating and life-threatening infection in the external auditory canal and the temporal bone. The aim of this paper is to evaluate the diagnostics and treatment of NEO and to recommend new guidelines. MATERIAL AND METHODS: Eleven patients were retrospectively enrolled under the code DH609 otitis externa without specification from 1 January 2000 to 31 December 2009. Records were reviewed to register: age, symptoms, clinical findings, comorbidity, imaging, microbiology and treatment. RESULTS: The median age was 75 years and the median time of therapy at the hospital was 6.3 months. All patients belonged to a risk group. A diagnostic delay was found resulting in further progression of the disease. In contrast to current international recommendations, the treatment consisted mostly of local antibiotics in combination with surgery. All patients survived, but most patients were left with hearing loss and psychiatric problems. CONCLUSION: A greater awareness of diagnostic criteria and a shift from local antibiotics to prolonged systemic monotherapy with ciprofloxacin in accordance with international concepts is recommended. Surgery should be left for extensive and refractory cases only. A list of diagnostic criteria and treatment guidelines is presented. FUNDING: Not relevant. TRIAL REGISTRATION: Not relevant.

Hepatic and biliary damage after transarterial chemoembolization for malignant hepatic tumors: incidence, diagnosis, treatment, outcome and mechanism.

OBJECTIVE: To provide an overview of recent studies on transarterial chemoembolization-related hepatic and biliary damage (TRHBD) in patients with malignant hepatic tumors (MHT) and to explore the reasons for TRHBD. METHODS: Literature on the treatments for MHT by TACE was sought in PubMed and the related information was summarized. RESULTS: TRHBD is found to occur in the hepatic parenchymal cells, biliary tree and blood-vascular system. The damage is mainly due to ischemia resulting from embolic materials such as gelatin sponge and lipiodol. In addition, clinicians' skill levels in non-superselective catheterization, the health condition of the patients, and the chemical agents used may also be related to the damage. Most of the deterioration can be reversed if the patients are diagnosed and treated properly and promptly. CONCLUSIONS: Understanding the mechanisms of TRHBD more comprehensively is helpful in developing effective methods for prevention and treatment.

αvß3 imaging can accurately distinguish between mature teratoma and necrosis in 18F-FDG-negative residual masses after treatment of non-seminomatous testicular cancer: a preclinical study.

PURPOSE: We assessed whether imaging α(v)ß(3) integrin could distinguish mature teratoma from necrosis in human non-seminomatous germ cell tumour (NSGCT) post-chemotherapy residual masses. METHODS: Human embryonal carcinoma xenografts (six/rat) were untreated (controls) or treated to form mature teratomas with low-dose cisplatin and all-trans retinoic acid (ATRA) over a period of 8 weeks. In another group, necrosis was induced in xenografts with high-dose cisplatin plus etoposide (two cycles). (18)F-Fluorodeoxyglucose ((18)F-FDG) small animal positron emission tomography (SA PET) imaging was performed in three rats (one control and two treated for 4 and 8 weeks with cisplatin+ATRA). Imaging of α(v)ß(3) expression was performed in six rats bearing mature teratomas and two rats with necrotic lesions on a microSPECT/CT device after injection of the tracer [(99m)Tc]HYNIC-RGD [6-hydrazinonicotinic acid conjugated to cyclo(Arg-Gly-Asp-D-Phe-Lys)]. Correlative immunohistochemistry studies of human and mouse α(v)ß(3) expression were performed. RESULTS: Cisplatin+ATRA induced differentiation of the xenografts. After 8 weeks, some glandular structures and mesenchymal cells were visible; in contrast, control tumours showed undifferentiated tissues. SA PET imaging showed that mature teratoma had very low avidity for (18)F-FDG [mean standardised uptake value (SUV(mean)) = 0.48 ± 0.05] compared to untreated embryonal carcinoma (SUV(mean) = 0.92 ± 0.13) (p = 0.005). α(v)ß(3) imaging accurately distinguished mature teratoma (tumour to muscle ratio = 4.29 ± 1.57) from necrosis (tumour to muscle ratio = 1.3 ± 0.26) (p = 0.0002). Immunohistochemistry studies showed that α(v)ß(3) integrin expression was strong in the glandular structures of mature teratoma lesions and negative in host stroma. CONCLUSION: Imaging α(v)ß(3) integrin accurately distinguished mature teratoma from necrosis following cisplatin-based treatment in human NSGCT xenografts.

In utero development of symmetric thalamic and brainstem necrosis in a preterm hydropic stillborn.

Focal and symmetric necrotic lesions of the brainstem are thought to result from fetal hypotension or cardiac arrest in the perinatal period and thus occur in the course of postnatal intensive care rather than in utero. Here, we report for the first time on brainstem necrosis in a preterm stillborn demonstrating that brainstem necrosis occurs already in utero. The preterm stillborn of 28 weeks gestation of a mother that suffered from HELLP-syndrome was severely affected by a fetal hydrops with bilateral pleural effusions and lung hypoplasia. Bilateral tegmental brainstem necrosis and thalamic lesions were detected.

Necrotizing soft tissue infections in the intensive care unit.

Necrotizing soft tissue infection is a severe illness that is associated with significant morbidity and mortality. It is often caused by a wide spectrum of pathogens and is most frequently polymicrobial. Care for patients with necrotizing soft tissue infection requires a team approach with expertise from critical care, surgery, reconstructive surgery, and rehabilitation specialists. The early diagnosis of necrotizing soft tissue infection is challenging, but the keys to successful management of patients with necrotizing soft tissue infection are early recognition and complete surgical debridement. Early initiation of appropriate broad-spectrum antibiotic therapy must take into consideration the potential pathogens. Critical care management components such as the initial fluid resuscitation, end-organ support, pain management, nutrition support, and wound care are all important aspects of the care of patients with necrotizing soft tissue infection. Soft tissue reconstruction should take into account both functional and cosmetic outcome.