Chemistry of the Au-Thiol Interface through the Lens of Single-Molecule Flicker Noise Measurements.

Chemistry of the Au-S interface at the nanoscale is one of the most complex systems to study, as the nature and strength of the Au-S bond change under different experimental conditions. In this study, using mechanically controlled break junction technique, we probed the conductance and analyzed Flicker noise for several aliphatic and aromatic thiol derivatives and thioethers. We demonstrate that Flicker noise can be used to unambiguously differentiate between stronger chemisorption (Au-SR) and weaker physisorption (Au-SRR') type interactions. The Flicker noise measurements indicate that the gold rearrangement in chemisorbed Au-SR junctions resembles that of the Au rearrangement in pure Au-Au metal contact breaking, which is independent of the molecular backbone structure and the resulting conductance. In contrast, thioethers showed the formation of a weaker physisorbed Au-SRR' type bond, and the Flicker noise measurement indicates the changes in the Au-anchoring group interface but not the Au-Au rearrangement like that in the Au-SR case. Additionally, by employing single-molecular conductance and Flicker noise analysis, we have probed the interfacial electric field-catalyzed ring-opening reaction of cyclic thioether under mild environmental conditions, which otherwise requires harsh chemical conditions for cleavage of the C-S bond. All of our conductance measurements are complemented by NEGF transport calculations. This study illustrates that the single-molecule conductance, together with the Flicker noise measurements can be used to tune and monitor chemical reactions at the single-molecule level.

Design, Virtual Screening, Molecular Docking, ADME and Cytotoxicity Studies of 1,3,5-Triazine Containing Heterocyclic Scaffolds as Selective BRAF Monomeric, Homo and Heterodimeric Inhibitors.

BACKGROUND: v-RAF murine sarcoma viral homolog B1 (BRAF) is one of the most frequently mutated kinases in human cancers. BRAF exhibits three classes of mutations: Class I monomeric mutants (BRAFV600), class II BRAF homodimer mutants (non-V600), and class III BRAF heterodimers (non-V600). METHOD: In this manuscript, the protein-ligand interaction site of all three mutants: BRAF monomer, BRAF homodimer BRAF2:14-3-32, and BRAF heterodimer BRAF:14-3-32:MEK (Mitogen extracellular Kinase) has been discussed. FDA-approved drugs still have limitations against all three classes of mutants, especially against the second and third classes. Using the DesPot grid model, 1114 new compounds were designed. Using virtual screening, the three PDB Ids 4XV2 for monomers, 7MFF for homodimers, and 4MNE for heterodimers were used for 1114 newly designed compounds. RESULT: Dabrafenib, encorafenib, sorafenib and vemurafenib were included as standard drugs. The top 10 hit molecules were identified for each protein. Additional binding studies were performed using molecular docking studies on the protein-ligand site of each PDB identifier. Absorption, distribution, metabolism, excretion (ADME) and toxicity studies were also performed. CONCLUSION: It was identified that top-hit molecules had better binding and interaction activity than standard in all three classes of mutants.

Annulation-Induced Hidden Reactivity of the 1,2,4-Triazole Backbone.

Triazoles are an important class of compounds with widespread applications. Functionalization of the triazole backbone is thus of significant interest. In comparison to 1,2,3-triazoles, C-H activation-functionalization of the congeners 1,2,4-triazoles is surprisingly underdeveloped. Indeed, no such C-H activation-functionalization has been reported for 4-substituted 1,2,4-triazole cores. Furthermore, although denitrogenative ring-opening of 1,2,3-triazoles is well-explored, 1,2,4-triazole/triazolium substrates have not been known to exhibit N-N bond-cleaving ring-opening reactivity so far. In this work, we unveiled an unusual hidden reactivity of the 1,2,4-triazole backbone involving the elusive N-N bond-cleaving ring-opening reaction. This new reactivity was induced by a Satoh-Miura-type C-H activation-annulation at the 1,2,4-triazole motif appended with a pyridine directing group. This unique reaction allowed ready access to a novel class of unsymmetrically substituted 2,2'-dipyridylamines, with one pyridine ring fully-substituted with alkyl groups. The unsymmetrical 2,2'-dipyridylamines were utilized to access unsymmetrical boron-aza-dipyridylmethene fluorescent dyes. Empowered with desirable optical/physical properties such as large Stokes shifts and suitable hydrophobicity arising from optimal alkyl chain length at the fully-substituted pyridine-ring, these dyes were used for intracellular lipid droplet-selective imaging studies, which provided useful information toward designing suitable lipid droplet-selective imaging probes for biomedical applications.

Full thickness macular hole with subfoveal pigment epithelial detachment in chronic central serous chorioretinopathy: A therapeutic challenge.

We describe the diagnostic and therapeutic strategies employed in the management of a patient with subfoveal pigment epithelial detachments (PEDs) combined with full-thickness macular hole (FTMH) and discuss the possible pathophysiology of these diseases occurring concurrently. A 38-year-old patient with a history of central serous chorioretinopathy (CSC) presented with FTMH overlying a large subfoveal serous PED. Multimodal imaging confirmed the same and intravitreal anti-vascular endothelial growth factor (VEGF) injections and eplerenone failed to resolve the PED. Spontaneous resolution of the large PED was observed later and pars plana vitrectomy with internal limiting membrane peeling closed the macular hole successfully. However, the PED with fibrinous CSC recurred postoperatively and low fluence photodynamic therapy (PDT) was done to tackle the same. At 10 months' follow-up, the final vision was 6/9, the macular hole remained closed, and the PED had not recurred. Macular hole formation may be the result of choroidal hyperpermeability and leakage in the backdrop of CSC which gives rise to an exudative component causing mechanical stretching and disruption of the overlying sensory retina. Spontaneous uncomplicated resolution of large subfoveal PED in CSCR is rare. This case was managed with a combination of intravitreal anti-VEGF injections, surgery, and PDT. The therapeutic challenge here was the timing of surgery.

A scoping review of persistent symptoms after COVID infection at different follow-up periods.

The clinical entity termed as long COVID has gained importance in the recent past. As this phenomenon is still evolving, it is important to document the magnitude of the syndrome during different time periods. This scoping review attempts to synthesize evidence generated from longitudinal studies which have follow-up periods beyond 3 months, up to 12 months. The review also documents the reported prevalence of long COVID for the different regions of the World Health Organization. Longitudinal studies published till March 2022 were systematically searched on PubMed, Google Scholar, and medRxiv. Among the identified 594 studies, 48 were included in this review. Data from selected studies were synthesized. The overall pooled prevalence of long COVID was 49% (40%-58%). The pooled estimates after 3 months, 4-6 months, 7-9 months, and 10-12 months were 44% (32%-57%), 50% (43%-57%), 49% (37%-62%), and 54% (46%-62%), respectively. Eastern Mediterranean Region (EMR) had the highest pooled prevalence of 63% (34%-92%] and the South East Asian Region (SEAR) had the least pooled estimate of 15% (10%-21%). The study brings out the high prevalence of long COVID even after 12 months of follow-up. It also shows the regional differences in the reported prevalence of the syndrome. This review highlights the need for well-planned follow-up studies, especially in developing nations to understand the magnitude and the pattern of long COVID-related symptoms as they emerge.

The Prevalence of Mild Cognitive Impairment (Mci) among Older Population of Rural Kerala: A Cross-Sectional Study.

Background: There are only very few studies on estimating the prevalence of mild cognitive impairment (MCI) from India, particularly from a rural setting. The available studies were heterogeneous. Objective: The study estimated the prevalence of MCI in a rural setting in Kerala, India. Materials and Methods: We conducted a community-based, cross-sectional study among individuals aged 65 and above in rural Thiruvananthapuram, Kerala. A cluster-randomized sampling was adopted, the cluster being the wards in the village. It was a two-phase door-to-door survey. Grassroots-level health workers enrolled 366 elders in the selected four wards in the initial phase and collected information on the sociodemographic details, comorbidities, and other risk factors of the participants, using a semi-structured questionnaire. Additionally, the Everyday Abilities Scale for India (EASI) was administered to assess their activities of daily living. In the second phase, a neurologist and a psychologist examined those screened positive with EASI and diagnosed MCI and dementia based on the MCI Working Group of the European Consortium on Alzheimer's Disease and the DSM V criteria, respectively. Results: The prevalence of MCI and dementia was 18.6% (95% confidence interval [CI] 14.7%-23.4%) and 6.8% (4.46%-10.1%), respectively, among the study participants. The prevalence of MCI was higher among the unemployed and those above 70 years of age. Conclusion: The community prevalence of MCI is more than three times that of dementia among the elderly in rural Kerala.

Combatting emerging infectious diseases from Nipah to COVID-19 in Kerala, India.

BACKGROUND: The state of Kerala, India, has experienced several unprecedented events in the past few years. The current study was an attempt to explore perceptions of stakeholders on how the decentralised system helped during the Nipah virus (NiV) outbreaks and COVID-19 pandemic in Kerala. METHODS: This study used a qualitative descriptive approach built on the advocacy paradigm. The stakeholders who were involved in decision-making and the representatives of local self-government who had real-time experience and had handled the challenges were identified using purposive sampling. Seven key informant interviews (KIIs) and nine in-depth interviews (IDIs) were conducted. RESULTS: Findings indicate that decentralisation had enabled the state to effectively deal with the outbreaks and the pandemic. The survey revealed four major themes: decision-making, engagement level, people-centric action, and difficulties. Two to four categories have emerged for each theme. CONCLUSION: The study results highlight the importance of human resources and service delivery as balancing factors during public health emergencies in any developing nation with limited resources. Given that very few nations have the healthcare infrastructure and resources necessary to cater to the healthcare needs of the whole population, decentralisation should be reinforced.

CONTEXTE: L'État du Kérala, Inde, a connu plusieurs évènements sans précèdent au cours des dernières années. Cette étude a cherché à analyser l'opinion des parties prenantes quant à l'aide apportée par le système décentralisé pendant les épidémies de virus Nipah (NiV) et la pandémie de COVID-19 au Kérala. MÉTHODES: Cette étude a eu recours à une méthode descriptive qualitative construite à partir du paradigme de mobilisation. Les parties prenantes impliquées dans la prise de décisions et les représentants des administrations locales autonomes, forts de leur expérience en temps réel et de leur expérience de gestion des défis, ont été identifiés par échantillonnage dirigé. Sept entretiens avec des informateurs clés (KII) et neuf entretiens approfondis (IDI) ont été réalisés. RÉSULTATS: Les résultats indiquent que la décentralisation a permis à l'État de gérer les épidémies et la pandémie de manière efficace. L'enquête a mis en évidence quatre thèmes majeurs : prise de décisions, niveau d'engagement, action centrée sur les personnes et difficultés. Chaque thème a pu être divisé en deux à quatre catégories. CONCLUSION: Les résultats de l'étude soulignent l'importance des ressources humaines et de la fourniture de services en tant que facteurs d'équilibre en période d'urgence de santé publique dans tous les pays en développement dotés de ressources limitées. Puisque très peu de pays disposent des infrastructures de santé et des ressources nécessaires pour répondre aux besoins sanitaires de l'ensemble de la population, la décentralisation devrait être renforcée.

Dithienylethene-Based Single Molecular Photothermal Linear Actuator.

By employing a mechanically controllable break junction technique, we have realized an ideal single molecular linear actuator based on dithienylethene (DTE) based molecular architecture, which undergoes reversible photothermal isomerization when subjected to UV irradiation under ambient conditions. As a result, open form (compressed, UV OFF) and closed form (elongated, UV ON) of dithienylethene-based molecular junctions are achieved. Interestingly, the mechanical actuation is achieved without changing the conductance of the molecular junction around the Fermi level over several cycles, which is an essential property required for an ideal single molecular actuator. Our study demonstrates a unique example of achieving a perfect balance between tunneling width and barrier height change upon photothermal isomerization, resulting in no change in conductance but a change in the molecular length, which results in mechanical actuation at the single molecular level.

A novel management of vertical root fracture in an endodontically treated mandibular premolar with titanium screw: A case report.

Introduction: Vertical root fracture is one of the conditions prevalent in endodontically treated teeth. The treatment options include extraction of the fracture fragment or the affected tooth as a whole. This case report highlights the successful management of vertical root fracture in an endodontically treated mandibular first premolar. Method: Surgical intervention was initiated, and a full-thickness flap was elevated. The separated fracture segment was safely retrieved, and the existing caries were removed and then reattached to the main fragment with the help of a titanium screw. The tooth was rehabilitated with a composite resin core followed by a porcelain-fused metal crown and the patient was followed up for 7 years. Result: The tooth was functional with evidence of new bone formation. Conclusion: Reattachment of the fracture fragments with a titanium screw might be considered as an option for managing vertical root fracture cases with poor prognosis.

Persistence of symptoms after Covid-19 infection in Kerala.

Background Persistence of symptoms following Covid-19 infection has now been recognized as an upcoming public health crisis. Understanding these persistent symptoms and quantifying them is vital in planning care for these patients. Studies from India estimating the magnitude of these persistent symptoms are scarce. We aimed to estimate the proportion of symptoms that persist among patients who have recovered from Covid-19 infection. Methods We conducted this descriptive study among 114 individuals after they recovered from Covid-19 infection. Participants diagnosed as Covid-positive at a tertiary care centre were included in the study. Data were collected from the participants through an online platform. Frequency and proportion of various persistent symptoms were estimated. Analysis was done using SPSS version 16. Results The mean (SD) age of the study participants was 35.5 (15.7) years. Women comprised 62.3% (n=71) of the population. Persistent symptoms were reported by 66 (57.9%; 95% CI 53.07-62.72) participants. The most common symptoms reported were fatigue (n=45, 39.5%) and joint pain (n=23, 20.2%). Those who required hospitalization for longer duration were found to be more associated with having persistent symptoms (p=0.018). Conclusion A sizable proportion of individuals had persistent symptoms after recovering from Covid-19 infection. Health facilities should be equipped to address these emerging issues.

Comparison of intravenous sildenafil with inhaled nitric oxide for acute vasodilator testing in pulmonary arterial hypertension.

Acute vasodilator testing (AVT) identifies acute responders for initiation of calcium channel blockers in pulmonary arterial hypertension (PAH) and operability in congenital heart disease (CHD). We sought to determine the feasibility of intravenous sildenafil (ivS) as an alternative to inhaled nitric oxide (iNO) in AVT. All patients with PAH undergoing cardiac catheterization for AVT (November 2015 to December 2020) were prospectively enrolled. Hemodynamic data were obtained at baseline, with iNO 20 ppm and ivS (0.25 mg/kg for children and 10 mg for adults). We studied 44 patients with a mean age of 20.5 ± 14.4 years (27 [61%] females and 20 [45%] children). There were 17 (38.6%) patients in the CHD group for operability assessment and 27 patients in non-CHD group (idiopathic pulmonary arterial hypertension-16 [36.3%], residual PAH after shunt closure-7 [15.9%], and 2 cases [4.5%] each of familial PAH and portopulmonary hypertension). There was an excellent intraclass correlation for mean pulmonary artery pressures (0.903, 95% confidence interval, CI: 0.809-0.949, p < 0.001), mean aortic pressures (0.745, 95% CI: 0.552-0.858, p < 0.001), pulmonary vascular resistance index (0.920, 95% CI: 0.858-0.956, p < 0.001), systemic vascular resistance (SVR) index (0.828, 95% CI: 0.706-0.902, p < 0.001), and the ratio of pulmonary and SVR indices (0.857, 95% CI: 0.752-0.919, p < 0.001) between the two agents. There were two responders, both in non-CHD group, and were identified by iNO and ivS. The hemodynamic effects of ivS show excellent correlation with iNO and could be a potential alternative agent for identifying acute responders during AVT.

Metabolic, behavioural, and psychosocial risk factors and cardiovascular disease in women compared with men in 21 high-income, middle-income, and low-income countries: an analysis of the PURE study.

BACKGROUND: There is a paucity of data on the prevalence of risk factors and their associations with incident cardiovascular disease in women compared with men, especially from low-income and middle-income countries. METHODS: In the Prospective Urban Rural Epidemiological (PURE) study, we enrolled participants from the general population from 21 high-income, middle-income, and low-income countries and followed them up for approximately 10 years. We recorded information on participants' metabolic, behavioural, and psychosocial risk factors. For this analysis, we included participants aged 35-70 years at baseline without a history of cardiovascular disease, with at least one follow-up visit. The primary outcome was a composite of major cardiovascular events (cardiovascular disease deaths, myocardial infarction, stroke, and heart failure). We report the prevalence of each risk factor in women and men, their hazard ratios (HRs), and population-attributable fractions (PAFs) associated with major cardiovascular disease. The PURE study is registered with ClinicalTrials.gov, NCT03225586. FINDINGS: In this analysis, we included 155 724 participants enrolled and followed-up between Jan 5, 2005, and Sept 13, 2021, (90 934 [58·4%] women and 64 790 [41·6%] men), with a median follow-up of 10·1 years (IQR 8·5-12·0). At study entry, the mean age of women was 49·8 years (SD 9·7) compared with 50·8 years (9·8) in men. As of data cutoff (Sept 13, 2021), 4280 major cardiovascular disease events had occurred in women (age-standardised incidence rate of 5·0 events [95% CI 4·9-5·2] per 1000 person-years) and 4911 in men (8·2 [8·0-8·4] per 1000 person-years). Compared with men, women presented with a more favourable cardiovascular risk profile, especially at younger ages. The HRs for metabolic risk factors were similar in women and men, except for non-HDL cholesterol, for which high non-HDL cholesterol was associated with an HR for major cardiovascular disease of 1·11 (95% CI 1·01-1·21) in women and 1·28 (1·19-1·39) in men, with a consistent pattern for higher risk among men than among women with other lipid markers. Symptoms of depression had a HR of 1·09 (0·98-1·21) in women and 1·42 (1·25-1·60) in men. By contrast, consumption of a diet with a PURE score of 4 or lower (score ranges from 0 to 8), was more strongly associated with major cardiovascular disease in women (1·17 [1·08-1·26]) than in men (1·07 [0·99-1·15]). The total PAFs associated with behavioural and psychosocial risk factors were greater in men (15·7%) than in women (8·4%) predominantly due to the larger contribution of smoking to PAFs in men (ie, 1·3% [95% CI 0·5-2·1] in women vs 10·7% [8·8-12·6] in men). INTERPRETATION: Lipid markers and depression are more strongly associated with the risk of cardiovascular disease in men than in women, whereas diet is more strongly associated with the risk of cardiovascular disease in women than in men. The similar associations of other risk factors with cardiovascular disease in women and men emphasise the importance of a similar strategy for the prevention of cardiovascular disease in men and women. FUNDING: Funding sources are listed at the end of the Article.

Demographic and clinical profile, surgical outcome, and quality of life in patients who underwent bilateral lamellar corneal grafts.

Purpose: Lamellar corneal grafts have revolutionized the management of corneal blindness by replacing only the disease specific corneal layers. To the best of our knowledge, there is no study in literature describing the outcomes of bilateral lamellar keratoplasty in the Indian population. The aim of this work was to study the demographic profile, surgical outcomes, and quality of life in patients who underwent bilateral lamellar keratoplasty and to assess the correlation between these three. Methods: An observational cross-sectional study was conducted on 47 patients who underwent bilateral deep anterior lamellar keratoplasty (DALK) (n = 31) or descemet stripping automated endothelial keratoplasty (DSAEK) (n = 16) with a minimum follow-up of 6 months after the second surgery. Demographic parameters were collected by interview, surgical outcomes by clinical examination, and quality of life by a questionnaire. Results: A total of 47 patients were evaluated, women 42.56%, (n = 20) and men 57.44% (n = 27) with 38.3% being in 18-30 years age group and 23.4% above 60 years; 17.02% patients had a good socioeconomic status (score >60) and 61.70% had poorer socioeconomic status (score <50). Quality of life score (VR-QoL) was ≥50 in 82.9% patients and ≥70 in 14.89%. No significant association existed between VR-QoL scores and demographic factors. However, statistically significant association existed between VR-QoL and age of patient (P < 0.05), postoperative vision (P ≤ 0.05), and contrast sensitivity (P ≤ 0.01). Conclusion: Bilateral lamellar corneal grafts provide satisfactory visual outcomes compatible with day-to-day functioning. VR-QoL has a direct correlation to the age, visual acuity, contrast sensitivity, and inverse correlation with lenticule thickness in DSAEK and residual bed thickness in DALK.

Pest scenario of Spodoptera litura (Fab.) on groundnut under representative concentration pathways (RCPs) based climate change scenarios.

Multi-model ensemble of Maximum (Tmax) and Minimum (Tmin) temperature data of four Representative Concentration Pathways viz., RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 of Coupled Model Intercomparison Project 5 (CMIP5) models were generated for ten major groundnut growing locations of the India to predict the number of generations of Spodoptera litura (Fab.) using Growing Degree Days approach during three future climate viz., Near (NF), Distant (DF) and Very Distant (VDF) periods and were compared over 1976-2005 baseline period (BL). Projections indicate significant increase in Tmax (0.7-4.7 °C) and Tmin (0.7-5.1 °C) in NF, DF and VDF periods under the four RCP scenarios at the ten groundnut growing locations. Higher percent increase of the number of generations of S. litura was predicted to occur in VDF (6-38%) over baseline, followed by DF (5-22%) and NF (4-9%) periods with reduction of generation time (5-26%) across the four RCP scenarios. Reduction of crop duration was higher (12-22 days) in long duration groundnut than in medium and short duration groundnut. Decrease in crop duration was higher in VDF (12.1-20.8 days) than DF (8.26-13.15 days) and NF (4.46-6.15 days) climate change periods under RCP 8.5 scenario. Increase in number of generations of S. litura was predicted even with altered crop duration of groundnut. Among locations, more number of generations of S. litura with reduced generation time are likely at Vridhachalam and Tirupathi locations. Geographical location (74-77%) and climate period (15-19%), together explained over 90 percent of the total variation in the number of generations and generation time of S. litura. These findings suggest that the incidence of S. litura on groundnut could be higher in future.

Perceived difficulties and complications in learners of phacoemulsification: A principal component analysis model.

PURPOSE: To evaluate the difficulty perceived of each step of phacoemulsification and analyze the factors affecting them. METHODS: Overall, 12 trainee residents were allotted 10 cases of phacoemulsification of eyes with senile cataract, under a single observer, and the steps of each surgery were rated from very easy to very difficult with a questionnaire. The completion rates of steps and complications of each surgery were noted. Principal component analysis of the responses to the difficulty level questionnaire was conducted to obtain factors resulting in the perceived difficulty. RESULTS: The lowest difficulty scores were for initial step of incision creation (1.63 ± 0.84), followed by intraocular lens insertion (2.51 ± 0.8). The most difficult step was divide/chop of the nucleus (3.74 ± 0.97) followed by phacoemulsification (3.32 ± 0.82). Highest completion rates were seen for the initial steps of the surgery and the lowest for divide/chop. We identified two major patterns of difficulty among the trainees - one for steps involving high amount of binocularity and the other, for steps involving high precision of hand control. The rate of complication of our study was within acceptable range. CONCLUSION: Although trainees have practiced phacoemulsification steps on simulation, real-life situation may bring in unprecedented level of difficulty and challenges, which may be documented and used for targeted improvement of surgical skills. Stereopsis and hand control training should form a major part of training modules of cataract surgery both on simulation and real-life scenarios.

Clinical presentation and management of corneal fistula.

PURPOSE: To describe the clinical features and management of corneal fistula in patients of healed keratitis. METHODS: Medical records of all patients of healed keratitis presenting to the cornea clinic from November 2016 to September 2017 were reviewed. Eightcases of corneal fistula (six true fistulas, two closed fistulas) were identified. Six patients were managed with autologous tenon patch graft while two patients were managed medically. Various risk factors and treatment outcomes of corneal fistulisation were evaluated. RESULTS: The patients included two patients of failed therapeutic keratoplasty (with resolved graft infection) and six patients of healed keratitis. The age of the patients ranged between 10 and 60 years. Five of the patients were male while three were female. The size of the fistula measured between 1 and 2 mm. A surrounding cystic area of diameter ranging between 1 and 4.5 mm was seen in all the patients. In all of the patients, the treating physician missed the diagnosis. Complete healing was noted at 6-8 weeks in all the patients who underwent tenon graft. One patient refused to undergo any surgery and was lost to follow-up. In another case, surgery was deferred due to uncontrolled hypertension and he developed anterior staphyloma subsequently. CONCLUSION: Corneal fistula can often be missed in an apparently healed perforated corneal ulcer. Tenon patch graft is an effective technique for the management of corneal fistula.

Pulmonary Hemorrhage Due to Unrecognized Bronchial Collateral After Arterial Switch Operation.

We report a neonate with transposition of great arteries and intact ventricular septum who had a massive pulmonary hemorrhage soon after an arterial switch operation. An emergency cardiac catheterization revealed a large bronchial collateral artery from the descending aorta feeding the right lung. The hemorrhage was controlled by coil embolization of the collateral, and the patient recovered after prolonged intensive care.