An Acquired Vulnerability of Drug-Resistant Melanoma with Therapeutic Potential.

BRAF(V600E) mutant melanomas treated with inhibitors of the BRAF and MEK kinases almost invariably develop resistance that is frequently caused by reactivation of the mitogen activated protein kinase (MAPK) pathway. To identify novel treatment options for such patients, we searched for acquired vulnerabilities of MAPK inhibitor-resistant melanomas. We find that resistance to BRAF+MEK inhibitors is associated with increased levels of reactive oxygen species (ROS). Subsequent treatment with the histone deacetylase inhibitor vorinostat suppresses SLC7A11, leading to a lethal increase in the already-elevated levels of ROS in drug-resistant cells. This causes selective apoptotic death of only the drug-resistant tumor cells. Consistently, treatment of BRAF inhibitor-resistant melanoma with vorinostat in mice results in dramatic tumor regression. In a study in patients with advanced BRAF+MEK inhibitor-resistant melanoma, we find that vorinostat can selectively ablate drug-resistant tumor cells, providing clinical proof of concept for the novel therapy identified here.

Inducing and exploiting vulnerabilities for the treatment of liver cancer.

Liver cancer remains difficult to treat, owing to a paucity of drugs that target critical dependencies1,2; broad-spectrum kinase inhibitors such as sorafenib provide only a modest benefit to patients with hepatocellular carcinoma3. The induction of senescence may represent a strategy for the treatment of cancer, especially when combined with a second drug that selectively eliminates senescent cancer cells (senolysis)4,5. Here, using a kinome-focused genetic screen, we show that pharmacological inhibition of the DNA-replication kinase CDC7 induces senescence selectively in liver cancer cells with mutations in TP53. A follow-up chemical screen identified the antidepressant sertraline as an agent that kills hepatocellular carcinoma cells that have been rendered senescent by inhibition of CDC7. Sertraline suppressed mTOR signalling, and selective drugs that target this pathway were highly effective in causing the apoptotic cell death of hepatocellular carcinoma cells treated with a CDC7 inhibitor. The feedback reactivation of mTOR signalling after its inhibition6 is blocked in cells that have been treated with a CDC7 inhibitor, which leads to the sustained inhibition of mTOR and cell death. Using multiple in vivo mouse models of liver cancer, we show that treatment with combined inhibition of of CDC7 and mTOR results in a marked reduction of tumour growth. Our data indicate that exploiting an induced vulnerability could be an effective treatment for liver cancer.

Effects of microplastics on the kidneys: a narrative review.

Microplastics (MPs) and nanoplastics are small synthetic organic polymer particles (<5 mm and <1 µm, respectively) that originate directly from plastic compounds or result from the degradation of plastic. These particles are a global concern because they are widely distributed in water, air, food, and soil, and recent scientific evidence has linked MPs to negative biological effects. Although these particles are difficult to detect in humans, MPs have been identified in different biological fluids and tissues, such as the placenta, lung, intestines, liver, blood, urine, and kidneys. Human exposure to MPs can occur by ingestion, inhalation, or dermal contact, potentially causing metabolic alterations. Data from experimental and clinical studies have revealed that the ability of MPs to promote inflammation, oxidative stress, and organ dysfunction and negatively affect clinical outcomes is associated with their accumulation in body fluids and tissues. Although evidence of the putative action of MPs in the human kidney is still scarce, there is growing interest in studying MPs in this organ. In addition, chronic kidney disease requires investigation because this condition is potentially prone to MP accumulation. The purpose of the present article is (i) to review the general aspects of MP generation, available analytic methods for identification, and the main known biological toxic effects; and (ii) to describe and critically analyze key experimental and clinical studies that support a role of MPs in kidney disease.

Robotic versus laparoscopic gastrectomy for gastric cancer: A Western propensity score matched analysis.

BACKGROUND: Robot-assisted gastrectomy (RG) has been shown to be safe and feasible in the treatment of gastric cancer (GC). However, it is unclear whether RG is equivalent to laparoscopic gastrectomy (LG), especially in the Western world. Our objective was to compare the outcomes of RG and LG in GC patients. METHODS: We reviewed all gastric adenocarcinoma patients who underwent curative gastrectomy by minimally invasive approach in our institution from 2009 to 2022. Propensity score matching (PSM) analysis was conducted to reduce selection bias. DaVinci Si platform was used for RG. RESULTS: A total of 156 patients were eligible for inclusion (48 RG and 108 LG). Total gastrectomy was performed in 21.3% and 25% of cases in LG and RG, respectively. The frequency of stage pTNM II/III was 48.1%, and 54.2% in the LG and RG groups (p = 0.488). After PSM, 48 patients were matched in each group. LG and RG had a similar number of dissected lymph nodes (p = 0.759), operative time (p = 0.421), and hospital stay (p = 0.353). Blood loss was lower in the RG group (p = 0.042). The major postoperative complications rate was 16.7% for LG and 6.2% for RG (p = 0.109). The 30-day mortality rate was 2.1% and 0% for LG and RG, respectively (p = 1.0). There was no significant difference between the LG and RG groups for disease-free survival (79.6% vs. 61.2%, respectively; p = 0.155) and overall survival (75.9% vs. 65.7%, respectively; p = 0.422). CONCLUSION: RG had similar surgical and long-term outcomes compared to LG, with less blood loss observed in RG.

Heterozygous deficiency of PHD2 restores tumor oxygenation and inhibits metastasis via endothelial normalization.

A key function of blood vessels, to supply oxygen, is impaired in tumors because of abnormalities in their endothelial lining. PHD proteins serve as oxygen sensors and may regulate oxygen delivery. We therefore studied the role of endothelial PHD2 in vessel shaping by implanting tumors in PHD2(+/-) mice. Haplodeficiency of PHD2 did not affect tumor vessel density or lumen size, but normalized the endothelial lining and vessel maturation. This resulted in improved tumor perfusion and oxygenation and inhibited tumor cell invasion, intravasation, and metastasis. Haplodeficiency of PHD2 redirected the specification of endothelial tip cells to a more quiescent cell type, lacking filopodia and arrayed in a phalanx formation. This transition relied on HIF-driven upregulation of (soluble) VEGFR-1 and VE-cadherin. Thus, decreased activity of an oxygen sensor in hypoxic conditions prompts endothelial cells to readjust their shape and phenotype to restore oxygen supply. Inhibition of PHD2 may offer alternative therapeutic opportunities for anticancer therapy.

Direct oral anticoagulants versus vitamin K antagonists in patients with atrial fibrillation and stage 5 chronic kidney disease under dialysis: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: In patients with atrial fibrillation (AF) and normal or slightly impaired renal function, the use of direct oral anticoagulants (DOACs) is preferable to vitamin K antagonists (VKAs). However, in patients undergoing hemodialysis, the efficacy, and safety of DOACs compared with VKAs are still unknown. PURPOSE: To review current evidence about the safety and efficacy of DOACs compared to VKAs, in patients with AF and chronic kidney disease under hemodialysis. METHODS: We systematically searched PubMed, Scopus, and Cochrane databases for RCTs comparing DOACs with VKAs for anticoagulation in patients with AF on dialysis therapy. Outcomes of interest were: (1) stroke; (2) major bleeding; (3) cardiovascular mortality; and (4) all-cause mortality. Statistical analysis was performed using RevMan 5.1.7 and heterogeneity was assessed by I2 statistics. RESULTS: Three randomized controlled trials were included, comprising a total of 383 patients. Of these, 218 received DOACs (130 received apixaban; 88 received rivaroxaban), and 165 were treated with VKAs (116 received warfarin; 49 received phenprocoumon). The incidence of stroke was significantly lower in patients treated with DOACs (4.7%) compared with those using VKAs (9.5%) (RR 0.42; 95% CI 0.18-0.97; p = 0.04; I2 = 0%). However, the difference was not statistically significant in the case of ischemic stroke specifically (RR 0.42; 95% CI 0.17-1.04; p = 0.06; I2 = 0%). As for the major bleeding outcome, the DOAC group (11%) had fewer events than the VKA group (13.9%) but without statistical significance (RR 0.75; 95% CI 0.45-1.28; p = 0.29; I2 = 0%). There was no significant difference between groups regarding cardiovascular mortality (RR 1.23; 95% CI 0.66-2.29; p = 0.52; I2 = 13%) and all-cause mortality (RR 0.98; 95% CI 0.77-1.24; p = 0.84; I2 = 16%). CONCLUSION: This meta-analysis suggests that in patients with AF on dialysis, the use of DOACs was associated with a significant reduction in stroke, and a numerical trend of less incidence of major bleeding compared with VKAs, but in this case with no statistical significance. Results may be limited by a small sample size or insufficient statistical power.

Serum levels of iCAF-derived osteoglycin predict favorable outcome in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by abundant stroma, the main cellular constituents of which are cancer-associated fibroblasts (CAFs). Stroma-targeting agents have been proposed to improve the poor outcome of current treatments. However, clinical trials using these agents showed disappointing results. Heterogeneity in the PDAC CAF population was recently delineated demonstrating that both tumor-promoting and tumor-suppressive activities co-exist in the stroma. Here, we aimed to identify biomarkers for the CAF population that contribute to a favorable outcome. RNA-sequencing reads from patient-derived xenografts (PDXs) were mapped to the human and mouse genome to allocate the expression of genes to the tumor or stroma. Survival meta-analysis for stromal genes was performed and applied to human protein atlas data to identify circulating biomarkers. The candidate protein was perturbed in co-cultures and assessed in existing and novel single-cell gene expression analysis from control, pancreatitis, pancreatitis-recovered and PDAC mouse models. Serum levels of the candidate biomarker were measured in two independent cohorts totaling 148 PDAC patients and related them to overall survival. Osteoglycin (OGN) was identified as a candidate serum prognostic marker. Single-cell analysis indicated that Ogn is derived from a subgroup of inflammatory CAFs. Ogn-expressing fibroblasts are distinct from resident healthy pancreatic stellate cells and arise during pancreatitis. Serum OGN levels were prognostic for favorable overall survival in two independent PDAC cohorts (HR = 0.47, P = .042 and HR = 0.53, P = .006). Altogether, we conclude that high circulating OGN levels inform on a previously unrecognized subgroup of CAFs and predict favorable outcomes in resectable PDAC.

Development of a low-cost congenital abdominal wall defect simulator (wall-go) for undergraduate medical education: a validation study.

BACKGROUND: Congenital Anomalies were responsible for 303,000 deaths in the neonatal period, according to the WHO, they are among the world's top 20 causes of morbidity and mortality. Expensive simulators demonstrate several diseases, but few are related to congenital anomalies. This study aims to develop, validate, and evaluate low-cost simulator models (WALL-GO) of the most common abdominal wall defects, gastroschisis, and omphalocele, to enable diagnosis through an accessible tool with study value and amenable to replication. METHODS: Market research was conducted to find materials to build low-cost models. The researchers built the model and underwent validation assessment of the selected experts who scored five or more in the adapted Fehring criteria. The experts were assessed through a 5-point Likert scale to 7 statements (S1-7). Statements were assigned values according to relevance in face and transfer validities. Concomitantly, the model was also evaluated by students from 1st to 5th year with the same instruments. Content Validity Indexes (CVIs) were considered validated between groups with concordance greater than 90%. Text feedback was also collected. Each statement was subjected to Fisher's Exact Test. RESULTS: Gastroschisis and omphalocele model costs were US $15 and US $27, respectively. In total, there were 105 simulator evaluators. 15 experts were selected. Of the 90 students, there were 16 (1st year), 22 (2nd), 16 (3rd), 22 (4th), and 14 (5th). Students and experts obtained CVI = 96.4% and 94.6%, respectively. The CVIs of each statement were not significantly different between groups (p < 0,05). CONCLUSIONS: The WALL-GO models are suitable for use and replicable at a manufacturable low cost. Mannequins with abdominal wall defects are helpful in learning to diagnose and can be applied in teaching and training health professionals in developing and low-income countries.

Multifunctional THz Graphene Antenna with 360∘ Continuous ϕ-Steering and θ-Control of Beam.

A novel graphene antenna composed of a graphene dipole and four auxiliary graphene sheets oriented at 90∘ to each other is proposed and analyzed. The sheets play the role of reflectors. A detailed group-theoretical analysis of symmetry properties of the discussed antennas has been completed. Through electric field control of the chemical potentials of the graphene elements, the antenna can provide a quasi-omnidirectional diagram, a one- or two-directional beam regime, dynamic control of the beam width and, due to the vertical orientation of the dipole with respect to the base substrate, a 360∘ beam steering in the azimuth plane. An additional graphene layer on the base permits control of the radiation pattern in the θ-direction. Radiation patterns in different working states of the antenna are considered using symmetry arguments. We discuss the antenna parameters such as input reflection coefficient, total efficiency, front-to-back ratio, and gain. An equivalent circuit of the antenna is suggested. The proposed antenna operates at frequencies between 1.75 THz and 2.03 THz. Depending on the active regime defined by the chemical potentials set on the antenna graphene elements, the maximum gain varies from 0.86 to 1.63.

Screening bacterial isolates for biocontrol of sheath blight in rice plants.

Sheath blight (Rhizoctonia solani) causes significant yield losses in rice (Oryza sativa L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial isolates as an antagonist to R. solani and identify the most efficient ones as sheath blight suppressors under greenhouse conditions. Two assays (E1 and E2) were performed in a completely randomized design with three replications. E1 tested 21 bacterial isolates antagonists to R. solani in vitro. E2 was conducted under greenhouse conditions, with rice cultivar BRS Pampeira sown in plastic pots (7 kg) containing fertilized soil. Sixty old plants were inoculated with a segment of a toothpick containing fragments of R. solani, followed by spray inoculation of a bacterial suspension (108 CFU/mL). The severity of the disease was determined by calculating the relative lesion size formed on the colm. Isolates BRM32112 (Pseudomonas nitroreducens), BRM65929 (Priestia megaterium), and BRM65919 (Bacillus cereus) reduced R. solani colony radial growth by 92.8, 77.56, and 75.56%, respectively while BRM63523 (Serratia marcescens), BRM65923 and BRM65916 (P. megaterium) and BRM65919 (B. cereus) with 23.45, 23.37, 23.62, and 20.17 cm, respectively were effective at suppressing sheath blight in greenhouse, indicating their potential as a biofungicide for sheath blight suppression.

Influence of compression therapy following varicose vein surgery: a prospective randomized study.

Background: The use of compression dressings after phlebectomy is based solely on clinical experience due to the lack of a unified set of definitive recommendations, which makes clinical practice extremely heterogeneous. Objectives: To evaluate compression therapy with elastic stockings for 7 days after phlebectomy. Methods: We randomly allocated 104 lower limbs with disease classified as C1 and C2 to 1 of 2 groups: an intervention group (64 limbs) - wearing elastic compression stockings for the first 7 days after phlebectomy; or a control group (40 limbs) - given conventional bandaging for 24 hours postoperatively. We compared clinical response by analyzing the evolution of symptoms, hematoma formation, and preoperative vs. postoperative limb volume. Results: Pain (median 1.0 vs. 1.5, p=0.0320) and limb volume (mean 43.7 vs. 99.8, p=0.0071) were significantly improved in patients wearing elastic compression stockings for 7 days after phlebectomy compared with controls. Conclusions: Use of elastic compression therapy for 7 days after phlebectomy was effective for improving pain and lower limb volume.

Contexto: O uso de curativos após flebectomia é baseado apenas na experiência clínica, visto que não existe um conjunto unificado de recomendações definitivas, o que torna a prática clínica extremamente variável. Objetivos: Avaliar o uso de terapia elástica compressiva por 7 dias após flebectomia. Métodos: Cento e quatro membros inferiores, classificados como CEAP C1 e C2, foram randomizados em dois grupos: grupo de intervenção (64 membros) ­ uso de meia elástica por 24 horas após a cirurgia ­ e grupo controle (40 membros) ­ uso de curativo convencional por 7 dias após a cirurgia. A resposta clínica foi comparada por meio de análise da evolução dos sintomas, de hematoma e do volume dos membros antes e depois da cirurgia. Resultados: Os pacientes submetidos a terapia compressiva elástica apresentaram melhora significativa na dor (mediana 1,0 vs. 1,5; p=0,0320) e no volume dos membros (média 43,7 vs. 99,8; p=0,0071) em comparação ao grupo controle. Conclusões: O emprego da terapia compressiva elástica por 7 dias após flebectomia mostrou-se efetivo na melhora da dor e do volume dos membros inferiores.

Evaluating the potential of Pediococcus pentosaceus as a biocontrol agent against tenuazonic acid-producing Alternaria alternata on livestock feeds.

AIMS: This study aims to demonstrate the potential of the lactic acid bacteria (LAB) Pediococcus pentosaceus LBM18 against the mycotoxin-producing Alternaria alternata TEF-1A and highlight its application as an effective grain silage inoculant to control mycotoxin contamination. METHODS AND RESULTS: The antifungal properties of Ped. pentosaceus lyophilized (PPL) were assessed by evaluating its effect on A. alternata TEF-1A grown in a corn silage-based medium, which included morphological changes by Scanning Electron Microscopy (SEM) observations, growth rate, conidia production assays, and inhibition of Tenuazonic acid (TeA) production by high-performance liquid chromatography (HPLC-MS/MS) analyses. Furthermore, TeA biosynthesis was monitored for changes at the molecular level by PKS gene expression. The growth and sporulation processes of A. alternata TEF-1A were affected by Ped. pentosaceus LBM18 in a concentration-dependent manner. Moreover, a significant inhibition of TeA production (74.3%) and the transcription level of the PKS gene (42.9%) was observed. CONCLUSIONS: Ped. pentosaceus is one of the promising LAB to be applied as an inoculant for corn silage preservation, aiming to inhibit mycotoxigenic fungi growth and their mycotoxin production. SIGNIFICANCE AND IMPACT OF THE STUDY: Ped. pentosaceus could be used as an inoculant to reduce fungal and mycotoxins contamination in grain silage production.

Production, Biochemical Characterization, and Kinetic/Thermodynamic Study of Inulinase from Aspergillus terreus URM4658.

Inulinases are enzymes involved in the hydrolysis of inulin, which can be used in the food industry to produce high-fructose syrups and fructo-oligosaccharides. For this purpose, different Aspergillus strains and substrates were tested for inulinase production by solid-state fermentation, among which Aspergillus terreus URM4658 grown on wheat bran showed the highest activity (15.08 U mL-1). The inulinase produced by this strain exhibited optimum activity at 60 °C and pH 4.0. A detailed kinetic/thermodynamic study was performed on the inulin hydrolysis reaction and enzyme thermal inactivation. Inulinase was shown to have a high affinity for substrate evidenced by very-low Michaelis constant values (0.78-2.02 mM), which together with a low activation energy (19.59 kJ mol-1), indicates good enzyme catalytic potential. Moreover, its long half-life (t1/2 = 519.86 min) and very high D-value (1726.94 min) at 60 °C suggested great thermostability, which was confirmed by the thermodynamic parameters of its thermal denaturation, namely the activation energy of thermal denaturation (E*d = 182.18 kJ mol-1) and Gibbs free energy (106.18 ≤ ΔG*d ≤ 111.56 kJ mol-1). These results indicate that A. terreus URM4658 inulinase is a promising and efficient biocatalyst, which could be fruitfully exploited in long-term industrial applications.

Extraction and purification of Aspergillus tamarii ß-fructofuranosidase with transfructosylating activity using aqueous biphasic systems (PEG/phosphate) and magnetic field.

ß-fructofuranosidases (FFases) are enzymes involved in sucrose hydrolysis and fructo-oligosaccharides' production which are of great interest for the food industry. FFase from Aspergillus tamarii URM4634 was extracted using PEG/Phosphate Aqueous Biphasic Systems (ABS), and the impact of magnetic field on the extraction behavior was evaluated. A 24-full experimental design was employed to study the influence of molar mass of PEG, concentrations of PEG and phosphate and pH on the selected response variables, i.e., partition coefficient (K), purification factor (PF), activity yield (Y) and selectivity (S). The influence of magnetic field during partition and NaCl concentration on the same responses was also studied. The best results of FFase extraction without magnetic field (K = 0.50, PF = 4.05, Y = 72.66% and S = 0.06) were observed at pH 8.0 using 12.5% (w/w) PEG 400 and 25% (w/w) NaH2PO4/K2HPO4. Application of the magnetic field allowed improving the performance, with the best results being obtained at the longest distance between magnets (lowest magnetic field) and absence of NaCl (K = 0.93, PF = 4.22, Y = 83.79% and S = 0.09). The outcomes obtained demonstrate that ABS combination with low intensity magnetic field can be used as an efficient FFase pre-purification method.

Extractive fermentation for process integration of protease production by Aspergillus tamarii Kita UCP1279 and purification by PEG-Citrate Aqueous Two-Phase System.

The present study evaluated the influence of the variables polyethylene glycol (PEG) molar mass, pH, PEG concentration and sodium citrate concentration in the integrated production of the protease from Aspergillus tamarii Kita UCP1279 by extractive fermentation, obtaining as a response the partition coefficient (K), activity yield (Y) and concentration factor (CF). The enzyme preferably partitioned to the top phase and obtained in the system formed by variables MPEG = 400 g mol-1, CPEG = 20% (w w-1), and CCIT = 20% (w w-1) and pH 6, in this condition were obtained CF = 1.90 and Y = 79.90%. The protease showed stability at a temperature of 60 °C for 180 min, with optimum temperature 40 °C and pH 8.0. For the ions and inhibitors effects, the protease activity increased when exposed to Fe2+, Ca2+ and Zn2 + and inhibited by EDTA, being classified as metalloprotease. The kinetic parameters Km (35.63 mg mL-1) and Vmax (1.205 mg mL-1 min-1) were also estimated. Thus, the protease showed desirable characteristics that enable future industrial applications, especially, for beer industry.

Novel Sterile Insect Technology Program Results in Suppression of a Field Mosquito Population and Subsequently to Reduced Incidence of Dengue.

BACKGROUND: There is a steady rise in the global incidence of Aedes-borne arbovirus disease. It has become urgent to develop alternative solutions for mosquito vector control. We developed a new method of sterilization of male mosquitoes with the goal to suppress a local Aedes aegypti population and to prevent the spread of dengue. METHODS: Sterile male mosquitoes were produced from a locally acquired Ae. aegypti colony by using a treatment that includes double-stranded RNA and thiotepa. A field study was conducted with sterile mosquito releases being performed on a weekly basis in predefined areas. There were 2 intervention periods (INT1 and INT2), with treatment and control areas reversed between INT1 and INT2. RESULTS: During INT1, releases in the treated area resulted in up to 91.4% reduction of live progeny of field Ae. aegypti mosquitoes recorded over time, while the control neighborhoods (no releases of sterile male mosquitoes) remained highly infested. The successful implementations of the program during INT1 and INT2 were associated with 15.9-fold and 13.7-fold lower incidences of dengue in the treated area compared to the control areas, respectively. CONCLUSIONS: Our data show the success of this new sterile insect technology-based program in preventing the spread of dengue.

Patterns of flow drainage from varicose veins originating in the incompetent great saphenous vein.

Background: Chronic venous insufficiency affects the lives of many people and therefore constitutes a public health problem. Knowledge of the drainage patterns of reflux from varicose veins secondary to incompetent saphenous veins is essential to define the best therapeutic management. Objectives: To determine the reflux drainage patterns from varicose veins originating in incompetent GSV, the prevalence of perforating veins (PV), and their relationships with symptoms. Methods: 55 ultrasound reports were analyzed to determine the drainage patterns of reflux from the GSV, location and diameter of PV drainage, and staging of symptoms. Results: In 64% of the sample, reflux from varicose veins drained to PVs, in 4% reflux drained to the GSV itself, in another 4% drainage was to the small saphenous vein, and in 29% drainage was to varicose trunk veins in which no direct communication with the deep system could be identified. No associations were observed between symptoms and reflux drainage patterns or PV diameters. Conclusions: For this sample, PVs were responsible for draining flow from varicose veins in 64% of cases. Neither PV diameters nor GSV reflux patterns were associated with severity of symptoms.

Introdução: A insuficiência venosa crônica impacta a vida de muitas pessoas, constituindo-se, assim, como um problema de saúde pública. Conhecer o padrão de drenagem do refluxo das varizes associadas à veia safena incompetente é fundamental para definir a melhor programação terapêutica. Objetivos: Determinar os padrões de drenagem do refluxo de varizes originadas da veia safena magna incompetente, a prevalência de veias perfurantes e a relação com os sintomas. Métodos: Foram analisados 55 registros ultrassonográficos de pacientes com refluxo da veia safena magna para determinar padrões de drenagem do refluxo dessa veia, pontos de refluxo das varizes, localização e diâmetro das perfurantes de drenagem e graduação dos sintomas. Resultados: O principal padrão de refluxo encontrado foi originado da junção safenofemoral com comprometimento proximal da veia safena magna. Em 64% dos pacientes, o refluxo das varizes drenou para veias perfurantes - 4% drenavam para a própria veia safena magna; em outros 4%, a drenagem era para a veia safena parva; e, em 29%, a drenavam destinava-se para varizes tronculares em que não se identificou comunicação direta com o sistema venoso profundo. Não foi observada associação dos sintomas com os padrões de drenagem do refluxo ou diâmetro das perfurantes. Conclusão: Para essa amostra, as veias perfurantes foram responsáveis pelo escoamento do fluxo oriundo das varizes em 64% dos casos. O diâmetro das veias perfurantes e o padrão de refluxo da veia safena não estiveram associados à gravidade dos sintomas.

Fibroblastic and bone marrow-derived cellularity in the corneal stroma.

The unwounded, normal corneal stroma is a relatively simple, avascular tissue populated with quiescent keratocytes, along with corneal nerves and a few resident dendritic and monocyte/macrophage cells. In the past, the resting keratocytes were thought of as a homogenous cellular population, but recent work has shown local variations in vimentin and nestin expression, and responsiveness to transforming growth factor (TGF)-ß1. Studies have also supported there being "stromal stem cells" in localized areas. After corneal wounding, depending on the site and severity of injury, profound changes in stromal cellularity occur. Anterior or posterior injuries to the epithelium or endothelium, respectively, trigger apoptosis of adjacent keratocytes. Many contiguous keratocytes transition to keratocan-negative corneal fibroblasts that are proliferative and produce limited amounts of disorganized extracellular matrix components. Simultaneously, large numbers of bone marrow-derived cells, including monocytes, neutrophils, fibrocytes and lymphocytes, invade the stroma from the limbal blood vessels. Ongoing adequate levels of TGFß1, TGFß2 and platelet-derived growth factor (PDGF) from epithelium, tears, endothelium and aqueous humor that penetrate defective or absent epithelial barrier function (EBF) and epithelial basement membrane (EBM) and/or Descemet's basement membrane (DBM) drive corneal fibroblasts and fibrocytes to differentiate into alpha-smooth muscle actin (SMA)-positive myofibroblasts. If the EBF, EBM and/or DBM are repaired or replaced in a timely manner, typically measured in weeks, then corneal fibroblast and fibrocyte progeny, deprived of requisite levels of TGFß1 and TGFß2, undergo apoptosis or revert to their precursor cell-types. If the EBF, EBM and/or DBM are not repaired or replaced, stromal levels of TGFß1 and TGFß2 remain elevated, and mature myofibroblasts are generated from corneal fibroblasts and fibrocyte precursors that produce prodigious amounts of disordered extracellular matrix materials associated with scarring fibrosis. This fibrotic stromal matrix persists, at least until the EBF, EBM and/or DBM are regenerated or replaced, and keratocytes remove and reorganize the affected stromal matrix.

Descemet's membrane injury and regeneration, and posterior corneal fibrosis, in rabbits.

The purpose of this investigation was to study Descemet's membrane and corneal endothelial regeneration, myofibroblast generation and disappearance, and TGF beta-1 localization after Descemet's membrane-endothelial excision (Descemetorhexis) in rabbits. Thirty-six rabbits had 8 mm Descemetorhexis and standardized slit lamp photos at 1, 2 and 4 days, 1, 2 and 4 weeks, and 2, 4 and 6 months, as well as multiplex IHC for stromal cell markers keratocan, vimentin, and alpha-smooth muscle actin (SMA); basement membrane (BM) components perlecan, nidogen-1, laminin alpha-5, and collagen type IV; and corneal endothelial marker Na,K-ATPase ß1, and TGF beta-1, with ImageJ quantitation. Stromal transparency increased from the periphery beginning at two months after injury and progressed into the central cornea by six months. At six months, central transparency was primarily limited by persistent mid-stromal neovascularization. Stromal myofibroblast zone thickness in the posterior stroma peaked at one month after injury, and then progressively decreased until to six months when few myofibroblasts remained. The regeneration of a laminin alpha-5 and nidogen-1 Descemet's membrane "railroad track" structure was accompanied by corneal endothelial closure and stromal cell production of BM components in corneas from four to six months after injury. TGF beta-1 deposition at the posterior corneal surface from the aqueous humor peaked at one day after Descemetorhexis and diminished even before regeneration of the endothelium and Descemet's membrane. This decrease was associated with collagen type IV protein production by corneal fibroblasts, and possibly myofibroblasts, in the posterior stroma. Descemet's membrane and the corneal endothelium regenerated in the rabbit cornea by six months after eight mm Descemetorhexis. Real-time quantitative RT-PCR experiments in vitro with marker-verified rabbit corneal cells found that 5 ng/ml or 10 ng/ml TGF beta-1 upregulated col4a1 or col4a2 mRNA expression after 6 h or 12 h of exposure in corneal fibroblasts, but not in myofibroblasts. Stromal cells produced large amounts of collagen type IV that likely decreased TGF beta-1 penetration into the stroma and facilitated the resolution of myofibroblast-generated fibrosis.

TGFß1 and TGFß2 proteins in corneas with and without stromal fibrosis: Delayed regeneration of apical epithelial growth factor barrier and the epithelial basement membrane in corneas with stromal fibrosis.

The purpose of this study was to investigate the expression and localization of transforming growth factor (TGF) ß1 and TGFß2 in rabbit corneas that healed with and without stromal fibrosis, and to further study defective perlecan incorporation in the epithelial basement membrane (EBM) in corneas with scarring fibrosis. A total of 120 female rabbits had no surgery, -4.5D PRK, or -9D PRK. Immunohistochemistry (IHC) was performed at time points from unwounded to eight weeks after surgery, with four corneas at each time point in each group. Multiplex IHC was performed for TGFß1 or TGFß2, with Image-J quantitation, and keratocan, vimentin, alpha-smooth muscle actin (SMA), perlecan, laminin-alpha 5, nidogen-1 or CD11b. Corneas at the four-week peak for myofibroblast and fibrosis development were evaluated using Imaris 3D analysis. Delayed regeneration of both an apical epithelial growth factor barrier and EBM barrier function, including defective EBM perlecan incorporation, was greater in high injury -9D PRK corneas compared to -4.5D PRK corneas without fibrosis. Defective apical epithelial growth factor barrier and EBM allowed epithelial and tear TGFß1 and tear TGFß2 to enter the corneal stroma to drive myofibroblast generation in the anterior stroma from vimentin-positive corneal fibroblasts, and likely fibrocytes. Vimentin-positive cells and unidentified vimentin-negative, CD11b-negative cells also produce TGFß1 and/or TGFß2 in the stroma in some corneas. TGFß1 and TGFß2 were at higher levels in the anterior stroma in the weeks preceding myofibroblast development in the -9D group. All -9D corneas (beginning two to three weeks after surgery), and four -4.5D PRK corneas developed significant SMA + myofibroblasts and stromal fibrosis. Both the apical epithelial growth factor barrier and/or EBM barrier functions tended to regenerate weeks earlier in -4.5D PRK corneas without fibrosis, compared to -4.5D or -9D PRK corneas with fibrosis. SMA-positive myofibroblasts were markedly reduced in most corneas by eight weeks after surgery. The apical epithelial growth factor barrier and EBM barrier limit TGFß1 and TGFß2 entry into the corneal stroma to modulate corneal fibroblast and myofibroblast development associated with scarring stromal fibrosis. Delayed regeneration of these barriers in corneas with more severe injuries promotes myofibroblast development, prolongs myofibroblast viability and triggers stromal scarring fibrosis.