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Laryngeal webs are abnormal formation of an epithelium-covered fibrous tissue between two structures within the larynx (Pegg et al. in Ear Nose Throat J 90(10):486-488, 2011). Most of the laryngeal webs occurs at the level of glottic region which may extend till anterior 1/3rd of vocal cords, but it can also extend in to posterior glottis and inferiorly till subglottic region (Singh in J Indian Assoc Pediatr Surg 14(3):108-109, 2009). Acquired laryngeal webs are more common than congenital laryngeal web. Idiopathic supraglottic web is a rare entity and only one case have been reported worldwide (Table 1). We report a case of an idiopathic acquired supraglottic web in a 27-year-old man. The web was managed with CO2 laser excision under micro laryngoscopy guidance.
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To the best of our knowledge, this is the largest case series describing the use of a melolabial flap for postlaryngectomy pharyngoplasty. It is an excellent alternative for pharyngoplasty, especially in cases post chemoradiotherapy. It accomplishes the goal while removing the restrictions of local and distant flaps. Although donor site morbidity is acceptable, specific consent is required due to the possibility of functional and cosmetic impairment. Additional cases with a larger sample size and a longer follow-up period can assist corroborate our first findings. In addition, because we tend to protect facial vessels for this flap, a follow-up about the compromise of oncological safety at level IB is required. In our case series, however, there was no recurrence until the final follow-up. As a result, it is a better option to pharyngoplasty post laryngectomy.
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Neoplasias Laríngeas , Laringectomia , Retalhos Cirúrgicos , Humanos , Carcinoma de Células Escamosas/cirurgia , Neoplasias Laríngeas/cirurgia , Laringectomia/efeitos adversos , Laringectomia/métodos , Faringectomia/métodos , Faringectomia/efeitos adversos , Faringe/cirurgia , Procedimentos de Cirurgia Plástica/métodosRESUMO
Background: Follow-up of patients treated for head and neck cancer is an important part of the overall treatment. Oral cancers are one of the leading causes of dysphagia. Swallowing dysfunction occurs owing to the disease itself, its predisposing factors, and the treatment. This study aims to evaluate swallowing dysfunction in patients with oral cavity cancers. Methods: This prospective study was carried out in a tertiary care hospital institution. Thirty patients with T3, T4 oral cancers were evaluated using institutional dysphagia score and fiber optic endoscopic evaluation of swallowing (FEES) (Penetration-Aspiration Scale, Yale Pharyngeal Residue Scale) before treatment, after surgery, and after adjuvant therapy. Results: Advanced-stage tumor, larger resections, and adjuvant therapy are risk factors for dysphagia postoperatively. Although the dysphagia score is our institutional score, the results are promising, that is, 10 % of patients having symptoms at baseline evaluation, which increased to 60% and 70% after surgery and adjuvant radiotherapy respectively. Our study findings of the Penetration Aspiration Scale are 13% aspiration rate at the baseline evaluation, which increased to 57% and 73% after surgery and after adjuvant radiotherapy, respectively, and these results are consistent with those of other report studies. The Vallecular Residual Scale showed that there was a significant association between three different timelines and demonstrated dysphagia among study subjects. Conclusion: Subjective and objective assessment of swallowing dysfunction before and after the treatment of head and neck cancers is underreported and underrecognized. Most of the patients in our study had significant swallowing impairment after treatment. FEES is a very effective procedure to diagnose dysphagia and will help in incorporating better preventative and rehabilitative measures.
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PURPOSE: Wilms' tumor is the most-frequent malignant-kidney tumor in children under 3-4 years of age and is caused by genetic alterations of oncogenes (OG) and tumor-suppressor genes (TG). Wilms' tumor has been linked to many OG-&-TG. However, only WT1 has a proven role in the development of this embryonic-tumor. METHODS: The study investigates the level of mRNA expression of 16 OGs and 20 TGs involved in key-signaling pathways, including chromatin modification; RAS; APC; Cell Cycle/Apoptosis; Transcriptional Regulation; PI3K; NOTCH-&-HH; PI3K & RAS of 24-fresh Wilms'-tumor cases by capture-and-reporter probe Code-Sets chemistry, as CNVs in these pathway genes have been reported. RESULTS: Upon extensively investigating, MEN1, MLL2, MLL3, PBRM1, PRDM1, SMARCB1, SETD2, WT1, PTPN11, KRAS, HRAS, NF1, APC, RB1, FUBP1, BCOR, U2AF1, PIK3CA, PTEN, EBXW7, SMO, ALK, CBL, EP300-and-GATA1 were found to be significantly up-regulated in 58.34, 62.5, 79.17, 91.67, 58, 66.66,54, 58.34, 66.67, 75, 62.5, 62.5, 58, 79.17, 79.17, 75, 70.84, 50, 50, 75, 66.66, 62.50, 61.66, 58.34-and-62.50% of cases respectively, whereas BRAF, NF2, CDH1, BCL2, FGFR3, ERBB2, MET, RET, EGFR-and-GATA2 were significantly down regulated in 58, 87.50, 79.16, 54.16, 79.17, 91.66, 66.66, 58.33, 91.66-and-62.50% of cases, respectively. Interestingly, the WT1 gene was five-fold down regulated in 41.66% of cases only. CONCLUSION: Hence, extensive profiling of OGs and TGs association of major-signaling pathways in Wilms' tumor cases may aid in disease diagnosis. PBRM1 (up-regulated in 91.67% of cases), ERBB2 and EGFR (down-regulated in 91.66 and 91.66% of cases, respectively) could be marker genes. However, validation of all relevant results in a larger number of samples is required.
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Neoplasias Renais , Tumor de Wilms , Criança , Cromatina , Classe I de Fosfatidilinositol 3-Quinases/genética , Proteínas de Ligação a DNA , Receptores ErbB , Genes Supressores , Humanos , Neoplasias Renais/genética , Neoplasias Renais/patologia , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , RNA Mensageiro , Proteínas de Ligação a RNA , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais/genética , Fator de Processamento U2AF/genética , Tumor de Wilms/genética , Tumor de Wilms/patologiaRESUMO
Objective: To study the potential role of subjective visual vertical (SVV) as a prognostic marker for canalith repositioning maneuver (CRM) in patients with posterior canal benign paroxysmal positional vertigo (PC-BPPV) for the Indian population. Methods: SVV was examined in 30 patients with PC-BPPV before and after canalith repositioning maneuver and after complete resolution of PC-BPPV. Study parameters included the mean of 10 angular tilt readings and direction of deviation, which were compared before and after CRM and following complete resolution of PC-BPPV. Results: The angle of SVV tilt was greater and deviated towards the affected ear before CRM in all patients, which decreased significantly shortly after CRM and continued to decrease after complete resolution of PC-BPPV (p < 0.0001). Conclusions: SVV can be used to test utricular dysfunction in PC-BPPV. The angle of tilt improves in response to CRM, which may be used as a prognostic marker in patients with PC-BPPV receiving CRM.
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Laryngeal histoplasmosis is a very rare cause of laryngitis which is encountered usually in the immunosuppressed states but can also occur in immunologically intact status. We report a rare case of laryngeal histoplasmosis in a man in his 60s, a chronic smoker who presented with a history of progressive hoarseness for 3 months. The glottic growth was biopsied. The rarity of diagnosis was aided by histopathological examination of the tissue, which revealed histoplasmosis. Management was done with intravenous liposomal amphotericin B and oral itraconazole with complete resolution of symptoms.
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Histoplasmose , Laringe , Neoplasias , Antifúngicos/uso terapêutico , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Humanos , Itraconazol/uso terapêutico , Laringe/patologia , Masculino , Neoplasias/tratamento farmacológicoRESUMO
PURPOSE: The choice of Esophageal replacement (ER) depends on surgeons' preference and patients' anatomical condition. A cross-sectional study was done to compare the long-term outcomes of two methods of ER, Gastric transposition (GT) and Colonic interposition (CI). METHODS: Children who had undergone ER from January 1997 to December 2017 with a minimum of two-year post-ER follow-up were evaluated by anthropometry, hepatobiliary scintigraphy, gastroesophageal reflux study, gastric emptying test, pulmonary function test and blood tests. RESULTS: Twenty-six (Male:female=17:9) children were recruited. The median age at ER was 13 months (interquartile range 9-40 months) and mean follow-up post-ER was 116.7 ± 76.4 months (range 24-247 months). GT:CI was done in 15(57.7%):11(42.3%) cases. A greater number of abnormal oral contrast studies (p = 0.02) and re-operations (p = 0.05) were documented as baseline characteristics with CI group. The presence of gastroesophageal reflux 9/23(39.1%), duodenogastric reflux 6/24(25%), delayed gastric emptying 6/25(24%), abnormal pulmonary function test 14/22(63.6%) were documented during the study period. However, there was no significant(p>0.05) difference in nutritional, developmental and functional outcomes of both operative methods of ER in the study. CONCLUSION: Assessment of nutritional, developmental and functional parameters in children after ER reveals good long-term results. There was no significant difference in CI and GT. LEVEL OF EVIDENCE: Comparative study; II.
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Atresia Esofágica , Refluxo Gastroesofágico , Criança , Pré-Escolar , Estudos Transversais , Atresia Esofágica/cirurgia , Feminino , Seguimentos , Refluxo Gastroesofágico/etiologia , Refluxo Gastroesofágico/cirurgia , Humanos , Lactente , Masculino , Estômago/cirurgiaRESUMO
Chyle leak is a dreadful complication in patients undergoing neck dissections. Octreotide has been used in the management of chyle leak post neck dissections in head and neck cancer patients. Currently there is no consensus and practice guidelines on the same. (1) To study the role of octreotide in early cessation of post neck dissection chyle leak. (2) To study incidence of intra-operative and post-operative CL, its relation to the extent of nodal disease and neck dissection, prior radiotherapy. Retrospective analysis of 16 patients out of 529 neck dissection over a period of 03 years between Jan 2016 and Dec 2019 who developed post-operative chyle leak. All patients who had post-operative chyle leak were administered octreotide. Time taken for chyle leak to stop was primary outcome. Secondary outcomes were duration of hospitalization post-operatively, incidence of intra-operative and post-operative chyle leak, its relation to the extent of nodal disease, prior radiotherapy and type of neck dissection. 59 of 529 neck dissections (11.15%) were noted to have intra-operative chyle leak. 16 of 529 neck dissections (3.02%) developed post-operative chyle leak. On applying chi square test, prior multimodality and N plus neck were found to be significant risk factors in developing postoperative chyle leak. Considering only RT versus no RT in prior multimodality treated group, the difference was insignificant. Onset of chyle leak varied from 1 to 5 post-op day (mean 2.68 days). 15 (93.75%) patients responded to octreotide. Chyle leak resolved between 3 and 10 days (mean 5.18 days) and octreotide was given for 5-12 days (mean-7.18 days). Overall duration of hospitalization ranged from 09 to 18 days (mean 12.18 days). 01 patient (6.25%) had to be re-explored due to high volume leak despite using octreotide. Adverse effects of octreotide were minimal and tolerable. Octreotide is effective in reducing the duration of chyle leak, hospital stay and need for surgical intervention. It may be considered as suitable adjunct to conservative measures in the management for post-operative chyle leak.
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Subglottic concretion is a rare and perilous condition usually presenting with existing or impending airway obstruction. Due to long-standing nature of the condition, slow progression of symptoms and rarity of occurrence, the condition is either missed or misdiagnosed. Its resemblance in presentation and symptoms to that of foreign body (FB) bronchus can lead to a diagnostic misadventure. Detailed history, chronology of symptoms and radiological imaging in conjunction with fiberoptic evaluation are keys for establishing correct diagnosis. Treatment outcomes in such cases depend on appropriate management approach with backup plan in tandem. We describe a child with ß thalassemia major with subglottic concretion, which was erroneously diagnosed and managed as a case of subglottic FB due to its classical history and presentation. The aim is to highlight the circumstances leading to this diagnostic misadventure with emphasis on airway management, problems faced and lessons learnt during the same.
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Obstrução das Vias Respiratórias , Corpos Estranhos , Talassemia beta , Obstrução das Vias Respiratórias/etiologia , Brônquios/diagnóstico por imagem , Criança , Sonhos , Corpos Estranhos/diagnóstico , Corpos Estranhos/diagnóstico por imagem , Humanos , Talassemia beta/complicações , Talassemia beta/diagnósticoRESUMO
The natural history of COVID-19 infection in children is still evolving as the pandemic unfolds. Few cases of severe and often fatal COVID-19 have been reported although the infection is mild in the large majority. Children with cancers are recognised as a high risk group for all infections. Since there aren't any definite treatment guidelines established in children with severe COVID, treatment is guided by adult recommendations which too are often not evidence based. We report the case of a 4-year-old girl with severe COVID-19 associated pneumonia who presented to us as febrile neutropenia. The use of convalescent plasma along with steroids and IVIG showed dramatic results in this child and she recovered without the need for any specific treatment. This is highlighted as one of the earliest cases that is reporting the use of convalescent plasma in a child; the first ever in a child with underlying malignancy.
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COVID-19/terapia , Neutropenia Febril/terapia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , COVID-19/etiologia , Pré-Escolar , Neutropenia Febril/complicações , Feminino , Humanos , Imunização Passiva , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Soroterapia para COVID-19RESUMO
Highly keratinized oral squamous cell carcinoma (OSCC) exhibits an improved response to treatment and prognosis compared with weakly keratinized OSCC. Therefore, we aimed to develop gene transcript signature and to identify novel full-length isoforms, fusion transcript and non-coding RNA to differentiate well-differentiated (WD) with Moderately Differentiated (MD)/Poorly Differentiated (PD)/WD-lymphadenopathy OSCC through, HTA, Isoform sequencing, and NanoString. Additionally, specific copy number gain and loss were also identify in WD keratinized OSCC through Oncoscan array and validated through Real-time PCR in histopathologically characterized FFPE-WD keratinized OSCC. Three-hundred-thirty-eight (338) differentially expressed full-length (FL) transcript isoforms (317 upregulated and 21 down-regulated in OSCC) were identified through Isoform Sequencing using the PacBio platform. Thirty-four (34) highly upregulated differentially expressed transcripts from IsoSeq data were also correlated with HTA2.0 and validated in 42 OSCC samples. We were able to identify 18 differentially expressed transcripts, 12 fusion transcripts, and two long noncoding RNAs. These transcripts were involved in increased cell proliferation, dysregulated metabolic reprogramming, oxidative stress, and immune system markers with enhanced immune rearrangements, suggesting a cancerous nature. However, an increase in proteasomal activity and hemidesmosome proteins suggested an improved prognosis and tumor cell stability in keratinized OSCC and helped to characterize WD with MD/PD/WD with lymphadenopathy OSCC. Additionally, novel isoforms of IL37, NAA10, UCHL3, SPAG7, and RAB24 were identified while in silico functionally validated SPAG7 represented the premalignant phenotype of keratinized (K4) OSCC. Most importantly we found copy number gain and overexpression of EGFR suggest that TKIs may also be used as therapeutics in WD-OSCCs.
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OBJECTIVES: Reconstruction of head and neck cancer ablative defects is challenging. A modification of the nasolabial flap (islanded pedicled nasolabial flap [ipNLF]) is an easy and reliable option for reconstruction of small- to medium-sized defects of the head and neck, especially in resource-constrained and high-volume centers. STUDY DESIGN AND METHODS: We present the retrospective analysis of 27 consecutive patients reconstructed with ipNLF at two high-volume cancer centers, Homi Bhabha Cancer Hospital, Varanasi, India; and Army Hospital Research and Referral, New Delhi, India. The functional outcomes measured were duration of weaning of feeding and tracheotomy tubes and speech assessment (speech intelligible rating score [SIR]) postsurgery. Complications assessed were flap loss, orocutaneous fistula, donor site wound dehiscence, oral incompetence, and angle of mouth deviation. RESULTS: The most common ablative defect was of the oral cavity (22 patients), followed by the oropharynx (4 patients) and hypopharynx (1 patient). The mean operating time for flap harvesting and insetting was 57.7 minutes. The mean durations for postoperative feeding tube and tracheotomy removal were 10 and 5 days, respectively. Twenty-four subjects had SIR scores of I or II. None of the subjects had flap loss, orocutaneous fistula, or donor site wound dehiscence. Twenty-five subjects had no oral incompetence, and 26 subjects had no or minimal angle of mouth deviation. CONCLUSION: This is the largest series of ipNLF to date and emphasizes the versatility, reliability, reproducibility and excellent functional and acceptable cosmetic outcomes of this flap for the reconstruction of judiciously chosen head and neck ablative defects. LEVEL OF EVIDENCE: 2C Laryngoscope, 130: 1967-1972, 2020.
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Neoplasias de Cabeça e Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Retalhos Cirúrgicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Lábio/transplante , Masculino , Pessoa de Meia-Idade , Nariz/transplante , Complicações Pós-Operatórias/epidemiologia , Estudos RetrospectivosRESUMO
Human liver is the primary and obligatory site for malaria infection where sporozoites invade host hepatocytes. Malaria hepatic stages are asymptomatic and represent an attractive target for development of anti-malarial interventions and vaccines. However, owing to lack of robust and reproducible in vitro culture system, it is difficult to target and study this imperative malaria liver stage. Here, we describe a procedure that allow cultivation and visualization of malaria hepatic stages including dormant hypnozoites using primary simian hepatocytes. This method enables sensitive and quantitative assessment of different hepatic stages in vitro.
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A major obstacle impeding malaria research is the lack of an in vitro system capable of supporting infection through the entire liver stage cycle of the parasite, including that of the dormant forms known as hypnozoites. Primary hepatocytes lose their liver specific functions in long-term in vitro culture. The malaria parasite Plasmodium initiates infection in hepatocyte. This corresponds to the first step of clinically silent infection and development of malaria parasite Plasmodium in the liver. Thus, the liver stage is an ideal target for development of novel antimalarial interventions and vaccines. However, drug discovery against Plasmodium liver stage is severely hampered by the poor understanding of host-parasite interactions during the liver stage infection and development. In this study, tandem mass tag labeling based quantitative proteomic analysis is performed in simian primary hepatocytes cultured in three different systems of susceptibility to Plasmodium infection. The results display potential candidate molecular markers, including asialoglycoprotein receptor, apolipoproteins, squalene synthase, and scavenger receptor B1 (SR-BI) that facilitate productive infection and full development in relapsing Plasmodium species. The identification of these candidate proteins required for constructive infection and development of hepatic malaria liver stages paves the way to explore them as therapeutic targets.
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Hepatócitos/metabolismo , Malária/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Animais , Células Cultivadas , Cromatografia Líquida , Hepatócitos/parasitologia , Interações Hospedeiro-Parasita , Humanos , Macaca fascicularis , Malária/parasitologia , Plasmodium/fisiologia , Proteoma/genética , Espectrometria de Massas em TandemRESUMO
Reconstruction of neopharynx after total laryngectomy is a challenging task. Various locoregional flaps like pectoralis major myocutaneos/ latismus dorsi flaps and free flaps have their own limitations and advantages. To overcome this, we used facial artery-based cutaneous island flap (melo-labial flap) for reconstruction of the neopharynx following total laryngectomy (DK Gupta technique). This flap is thin, pliable, without any gravitational pull and without any risk of anastomosis failure and hence has advantage of both locoregional and free flaps and eliminates the limitations of both. It is simple, reproducible and reliable reconstructive option for neopharynx. We present a case report, review of literature and this novel technique for an excellent outcome and recommend to use it as the new workhorse of neopharyngeal reconstruction.
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Retalhos de Tecido Biológico/transplante , Neoplasias Laríngeas/cirurgia , Laringectomia/métodos , Faringe/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Artérias/transplante , Face/irrigação sanguínea , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Plasmodium vivax hypnozoites persist in the liver, cause malaria relapse and represent a major challenge to malaria elimination. Our previous transcriptomic study provided a novel molecular framework to enhance our understanding of the hypnozoite biology (Voorberg-van der Wel A, et al., 2017). In this dataset, we identified and characterized the Liver-Specific Protein 2 (LISP2) protein as an early molecular marker of liver stage development. Immunofluorescence analysis of hepatocytes infected with relapsing malaria parasites, in vitro (P. cynomolgi) and in vivo (P. vivax), reveals that LISP2 expression discriminates between dormant hypnozoites and early developing parasites. We further demonstrate that prophylactic drugs selectively kill all LISP2-positive parasites, while LISP2-negative hypnozoites are only sensitive to anti-relapse drug tafenoquine. Our results provide novel biological insights in the initiation of liver stage schizogony and an early marker suitable for the development of drug discovery assays predictive of anti-relapse activity.
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Malária Vivax/genética , Plasmodium cynomolgi/genética , Plasmodium vivax/genética , Proteínas de Protozoários/genética , Aminoquinolinas/farmacologia , Animais , Antimaláricos/farmacologia , Biomarcadores/metabolismo , Biomarcadores Farmacológicos , Hepatócitos/metabolismo , Hepatócitos/parasitologia , Interações Hospedeiro-Parasita/genética , Humanos , Fígado/efeitos dos fármacos , Fígado/parasitologia , Macaca mulatta/genética , Macaca mulatta/parasitologia , Malária Vivax/tratamento farmacológico , Malária Vivax/parasitologia , Plasmodium cynomolgi/parasitologia , Plasmodium vivax/efeitos dos fármacos , Plasmodium vivax/patogenicidade , Proteínas de Protozoários/metabolismo , Esporozoítos/genética , Transcriptoma/efeitos dos fármacosRESUMO
BACKGROUND: The genetic association of hypospadias-risk studies has been conducted in Caucasians, Chinese-Han populations and few in Indian populations. However, no comprehensive approach has been followed to assess genetic involvement in the severity of the disorder. METHODS: The study evaluated to establish the correlation between genotyped single nucleotide and copy number variants (SNPs/CNVs) and severity of hypospadias by an association in a total 30 SNPs in genes related to sex hormone-biosynthesis and metabolism; embryonic-development and phospholipase-D-signalling pathways on 138 surgery-confirmed hypospadias-cases from North India (84 penile and 28 cases of penoscrotal-hypospadias as compared with 31 cases of glanular + coronal), and analyzed and identified CNVs in four familial cases (18 members) and three paired-sporadic cases (6 members) using array-based comparative-genomic-hybridization and validated in 32 hypospadias samples by TaqMan assay. RESULTS: Based on odds ratio at 95% CI, Z Statistic and Significance Levels, STS gene-rs17268974 was associated with Penile-Hypospadias and 9-SNPs [seven-SNPs (rs5934740; rs5934842; rs5934913; rs6639811; rs3923341; rs17268974; rs5934937)] of STS gene; rs7562326-SRD5A2 and rs1877031-STARD3 were associated with penoscrotal-hypospadias. On aggregate analysis with p < 0.001, we identified homozygous-loss of Ch7:q34 (PRSS3P2, PRSS2). On validation in previously CNV-characterized and new (32 hypospadias cases), we identified PRSS3P2-loss in most of the grade 3 and 4 hypospadias. Hence, Grade 1 and 2 (coronal and granular) show no-PRSS3P2-loss and no-association with SNPs in STS; SRD5A2; STARD3-gene but Grade 3 and 4 (Penile and Penoscrotal) show PRSS3P2-loss accompanied with the association of SNPs in STS; SRD5A2; STARD3. CONCLUSIONS: Hence, homozygous-loss of PRSS3P2 accompanied with the association of STS; SRD5A2; STARD3 may link to the severity of the disease.
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Variações do Número de Cópias de DNA , Hipospadia/genética , Polimorfismo de Nucleotídeo Único , Índice de Gravidade de Doença , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/genética , Proteínas de Transporte/genética , Genótipo , Humanos , Masculino , Proteínas de Membrana/genética , Esteril-Sulfatase/genética , Tripsina/genéticaRESUMO
Artemisinin (ART) resistance has spread through Southeast Asia, posing a serious threat to the control and elimination of malaria. ART resistance has been associated with mutations in the Plasmodium falciparum kelch-13 (Pfk13) propeller domain. Phenotypically, ART resistance is defined as delayed parasite clearance in patients due to the reduced susceptibility of early ring-stage parasites to the active metabolite of ART dihydroartemisinin (DHA). Early rings can enter a state of quiescence upon DHA exposure and resume growth in its absence. These quiescent rings are referred to as dormant rings or DHA-pretreated rings (here called dormant rings). The imidazolopiperazines (IPZ) are a novel class of antimalarial drugs that have demonstrated efficacy in early clinical trials. Here, we characterized the stage of action of the IPZ GNF179 and evaluated its activity against rings and dormant rings in wild-type and ART-resistant parasites. Unlike DHA, GNF179 does not induce dormancy. We show that GNF179 is more rapidly cidal against schizonts than against ring and trophozoite stages. However, with 12 h of exposure, the compound effectively kills rings and dormant rings of both susceptible and ART-resistant parasites within 72 h. We further demonstrate that in combination with ART, GNF179 effectively prevents recrudescence of dormant rings, including those bearing pfk13 propeller mutations.
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Antimaláricos/farmacologia , Artemisininas/farmacologia , Imidazóis/farmacologia , Piperazinas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Esquizontes/efeitos dos fármacos , Esquizontes/metabolismo , Trofozoítos/efeitos dos fármacos , Trofozoítos/metabolismoRESUMO
Plasmodium liver hypnozoites, which cause disease relapse, are widely considered to be the last barrier towards malaria eradication. The biology of this quiescent form of the parasite is poorly understood which hinders drug discovery. We report a comparative transcriptomic dataset of replicating liver schizonts and dormant hypnozoites of the relapsing parasite Plasmodium cynomolgi. Hypnozoites express only 34% of Plasmodium physiological pathways, while 91% are expressed in replicating schizonts. Few known malaria drug targets are expressed in quiescent parasites, but pathways involved in microbial dormancy, maintenance of genome integrity and ATP homeostasis were robustly expressed. Several transcripts encoding heavy metal transporters were expressed in hypnozoites and the copper chelator neocuproine was cidal to all liver stage parasites. This transcriptomic dataset is a valuable resource for the discovery of vaccines and effective treatments to combat vivax malaria.