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1.
BMC Surg ; 24(1): 116, 2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38643112

RESUMEN

BACKGROUND: Pancreatic ductal carcinoma (PDAC) is an extremely poor prognostic disease. Even though multidisciplinary treatment for PDAC has developed, supportive therapies, such as nutritional therapy or perioperative rehabilitation to sustain and complete aggressive treatment, have not yet been well-established in PDAC. The aim of this study was to elucidate the relationship between the combined index using psoas muscle mass index (PMI) values and controlling nutritional status (CONUT) score and prognosis. METHODS: We included 101 patients diagnosed with PDAC who underwent radical pancreatectomy with regional lymphadenectomy. The cut-off value was set at the first quartile (male, 6.3 cm2/m2; female 4.4 cm2/m2), and patients were classified into high PMI and low PMI groups. A CONUT score of 0 to 1 was classified as the normal nutritional status group, and 2 or more points as the malnutritional status group. Patients were further divided into three groups: high PMI and normal nutrition (good general condition group), low PMI and low nutrition (poor general condition group), and none of the above (moderate general condition group). We performed a prognostic analysis of overall survival (OS), stratified according to PMI values and CONUT scores. RESULTS: In the poor general condition group, the proportion of elderly people over 70 years of age was significantly higher than that in the other groups (p < 0.001). The poor general condition group had a significantly worse prognosis than the good and moderate general condition groups (p = 0.012 and p = 0.037). The 5-year survival rates were 10.9%, 22.3%, and 36.1% in the poor, moderate, and good general condition groups, respectively. In multivariate analysis, poor general condition, with both low PMI and malnutrition status, was an independent poor prognostic factor for postoperative OS (hazard ratio 2.161, p = 0.031). CONCLUSIONS: The combination of PMI and CONUT scores may be useful for predicting the prognosis of patients with PDAC after radical surgery.


Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Masculino , Femenino , Anciano , Anciano de 80 o más Años , Estado Nutricional , Pronóstico , Carcinoma Ductal Pancreático/complicaciones , Carcinoma Ductal Pancreático/cirugía , Carcinoma Ductal Pancreático/patología , Músculos Psoas , Estudios Retrospectivos , Neoplasias Pancreáticas/complicaciones , Neoplasias Pancreáticas/cirugía , Neoplasias Pancreáticas/patología
2.
Int J Surg Case Rep ; 115: 109247, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38219514

RESUMEN

INTRODUCTION: Soft coagulation is a hemostatic system of electrosurgical units that automatically regulates its output to avoid carbonization or incision. This system is widely used in invasive procedures, including thoracic surgery. Few reports exist on the harmful effects of these devices. Herein, we encountered a case of an esophagopleural fistula caused by soft coagulation. PRESENTATION OF CASE: A 74-year-old man with a history of bladder cancer was diagnosed with a tumor in the right lower lung lobe 2.5 cm in diameter. A thoracoscopic right lower lobectomy with lymph node dissection was performed. During surgery, hemostasis using soft coagulation was performed on the right wall of the lower esophagus. Eight days after surgery, thoracoscopic empyema curettage and drainage were performed. Three days after the second surgery, an esophageal fistula was identified. Suturing for the esophageal fistula and omentoplasty were performed. Suture failure occurred and an esophagobronchial fistula developed after the third surgery, which was reduced by drainage, antibiotics, and enteral nutrition. The fistula was finally addressed by fibrin glue filling in its cavity. DISCUSSION: Soft coagulation helps manage hemostasis and contributes to safe surgery. However, it may cause severe complications owing to the unpredictable spread of heat denaturation. It is suspected that delayed esophageal perforation was caused by an unnoticed heat injury to the deeper layer of the esophageal wall. CONCLUSION: There have been no reports of esophagus injury caused by soft coagulation exept for our experience. Although soft coagulation is a useful device owing to its excellent hemostatic capacity, the spread of heat denaturation may cause unpredictable tissue damage. Extra caution should be observed when using this device for hemostasis.

3.
Langenbecks Arch Surg ; 408(1): 430, 2023 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-37938415

RESUMEN

PURPOSE: Recently, systemic inflammatory responses (SIR) have been shown to play a pivotal role in the development and progression of cancer. We previously reported that four factors, serum carcinoembryonic antigen (> 7 ng/dL), serum albumin (< 3.5 g/dL), C-reactive protein (> 0.5 mg/dL), and platelet-lymphocyte ratio (PLR; > 150), were independent prognostic factors after perihilar cholangiocarcinoma (PHCC) surgery. We also advocated a prognosis predictive preoperative prognostic score (PPS) using these four factors and showed that PPS could predict patients' prognosis on survival. This retrospective study sought to validate preoperatively available prognostic factors for survival after major hepatectomy as reported previously, including PPS for PHCC. METHODS: We retrospectively validated our PPS score and reported SIR scoring systems using the data of 125 consecutive patients who underwent PHCC surgery from January 2010 to November 2020. RESULTS: PPS was an independent preoperative prognostic factors for survival. The T and N categories were independent prognostic factors. Other SIR scores were not independent preoperative factors in the univariate analysis. Among SIR scores, only the PPS was found to be associated with OS and disease-free survival. The PPS was also associated with histopathological factors (T and N categories). CONCLUSION: PPS could be useful in predicting long-term survival after PHCC and may be a more useful scoring system than other SIR systems.


Asunto(s)
Neoplasias de los Conductos Biliares , Tumor de Klatskin , Humanos , Tumor de Klatskin/cirugía , Pronóstico , Estudios Retrospectivos , Proteína C-Reactiva , Neoplasias de los Conductos Biliares/cirugía
5.
Cereb Cortex ; 33(4): 1383-1402, 2023 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-35860874

RESUMEN

Where in the brain consciousness resides remains unclear. It has been suggested that the subnetworks supporting consciousness should be bidirectionally (recurrently) connected because both feed-forward and feedback processing are necessary for conscious experience. Accordingly, evaluating which subnetworks are bidirectionally connected and the strength of these connections would likely aid the identification of regions essential to consciousness. Here, we propose a method for hierarchically decomposing a network into cores with different strengths of bidirectional connection, as a means of revealing the structure of the complex brain network. We applied the method to a whole-brain mouse connectome. We found that cores with strong bidirectional connections consisted of regions presumably essential to consciousness (e.g. the isocortical and thalamic regions, and claustrum) and did not include regions presumably irrelevant to consciousness (e.g. cerebellum). Contrarily, we could not find such correspondence between cores and consciousness when we applied other simple methods that ignored bidirectionality. These findings suggest that our method provides a novel insight into the relation between bidirectional brain network structures and consciousness.


Asunto(s)
Conectoma , Estado de Conciencia , Animales , Ratones , Conectoma/métodos , Encéfalo , Imagen por Resonancia Magnética/métodos
6.
BMC Gastroenterol ; 22(1): 390, 2022 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-35982420

RESUMEN

BACKGROUND: Multi-matrix mesalazine (MMX) is an important treatment for ulcerative colitis (UC); however, it is often excreted intact, which increases the risk of relapse. This study aimed to clarify the risk factors for insoluble MMX excretion. METHODS: The subjects were 102 UC patients who were newly prescribed MMX alone to induce remission. Their stools were evaluated on the Bristol Stool Form Scale (BSFS), the presence/absence of insoluble MMX excretion was investigated in interviews, and defecation frequency at the start of treatment and disease type were retrospectively investigated by examining their medical records. RESULTS: The insoluble excretion rate (IER) was 14.7%. It tended to be higher in the patients with left-sided colitis or extensive colitis, although the differences among the disease types were not significant (p = 0.053). The mean defecation frequency of the patients that reported insoluble MMX excretion was significantly higher than that of the patients that did not report it (6.27 ± 5.28 vs. 3.69 ± 3.17, p < 0.05). The IER tended to be higher among the patients with soft stools (4.5%, 21.9%, and 23.1% in those with BSFS scores of ≤ 4, 5, and ≥ 6, respectively). In ROC analysis of defecation frequency, ≥ 3.5 defecations was found to exhibit sensitivity and specificity of 66.7% and 65.5%, respectively, for predicting insoluble MMX excretion. CONCLUSIONS: The likelihood of insoluble MMX excretion is influenced by defecation frequency and the extent of inflammation. It is important to keep the possibility of insoluble excretion in mind when prescribing MMX.


Asunto(s)
Colitis Ulcerosa , Mesalamina , Antiinflamatorios no Esteroideos/uso terapéutico , Colitis Ulcerosa/inducido químicamente , Colitis Ulcerosa/tratamiento farmacológico , Humanos , Mesalamina/uso terapéutico , Estudios Retrospectivos , Sensibilidad y Especificidad
7.
PLoS One ; 17(3): e0265333, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35298522

RESUMEN

The infrapatellar fat pad plays a biomechanical role in the knee joint. After knee injury or surgery, its dynamics decrease because of an inflammatory response. Physical therapy might be one of the valuable treatments for the recovery of knee joint mobility. This study aimed to evaluate the immediate effect of physical therapy on the dynamics of the infrapatellar fat pad in healthy participants using ultrasonography. In this prospective, single-blind, randomised controlled trial, 64 healthy young participants were enrolled and randomly assigned to one of the following three interventions: manual therapy, hot pack treatment, and control. Ultrasound images of the infrapatellar fat pad were obtained before and after the intervention. The thickness change ratio of the infrapatellar fat pad was calculated to compare the changes between and within groups before and after the intervention. No significant inter-group differences were observed. The effect sizes were relatively small. Manual therapy or hot pack intervention might not have an immediate effect on infrapatellar fat pad flexibility in healthy participants. Thus, it is necessary to consider more intensive treatments to change the dynamics of the infrapatellar fat pad.


Asunto(s)
Tejido Adiposo , Articulación de la Rodilla , Tejido Adiposo/fisiología , Humanos , Articulación de la Rodilla/fisiología , Modalidades de Fisioterapia , Estudios Prospectivos , Método Simple Ciego
8.
Sci Rep ; 12(1): 1189, 2022 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-35075225

RESUMEN

Although there are increasing reports on the usefulness of sonopalpation with ultrasound imaging, many previous studies have reported interventions without a control group. This single-blind, parallel-group randomised controlled trial aimed to determine whether educational instruction with sonopalpation for physical therapy students has a more superior effect on skill improvement than traditional instruction without ultrasonography. Twenty-nine physical therapy students participated in the study and were randomised using block randomisation into an ultrasound imaging group (n = 15) and a control group (n = 14). Subsequently, they underwent three training sessions focusing on the shoulder joint. Participants underwent a scoring assessment of their palpation skills at pre-intervention, post-intervention, and follow-up 3 months after training. The raters were blinded to the subjects' group. The Friedman and Mann-Whitney U tests were used for data analysis. The intervention group showed a significant increase in scores at post-intervention and the 3-month follow-up; the effect sizes were large (0.849 and 0.849, respectively). A comparison of the scores at different time points after the intervention at the 3-month follow-up revealed no significant difference between the groups. Education using ultrasound imaging may be non-inferior to education without it; nevertheless, further studies are needed to demonstrate superiority.


Asunto(s)
Palpación/normas , Modalidades de Fisioterapia/educación , Ultrasonografía , Humanos , Articulación del Hombro/diagnóstico por imagen
10.
Org Biomol Chem ; 19(42): 9148-9153, 2021 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-34523640

RESUMEN

A novel, Cu-mediated protocol toward the 1,2-bis-perfluoroalkyaltion of alkenes/alkynes was developed. The method proceeded with perfluorocarboxylic anhydrides as inexpensive and readily available perfluoroalkyl sources. Diacyl peroxide was generated in situ from the perfluorocarboxylic anhydrides and H2O2. The key step in this reaction is the formation of a stable perfluoroalkylcopper intermediate that is achieved with the aid of a bipyridyl ligand. Subsequent reaction of the intermediate with perfluoroalkyl-containing alkyl or vinyl radicals affords the desired products.

11.
J Clin Biochem Nutr ; 68(1): 32-36, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33536710

RESUMEN

The indicator amino acid oxidation (IAAO) method is a recently developed method to determine the protein requirement and is particularly useful for analyzing human subjects because of its minimal invasiveness. IAAO study is performed using two-phase regression analysis, with the break-point between these phases being the estimated average requirement. However, this method requires that the break-point lie within a certain range in advance, which is in practice difficult. Recently, the change-point regression model (CPRM) has been proposed to be more effective for two-phase regression analysis. There is also a need to re-evaluate the value corresponding to the recommended dietary allowance. Calculation of the recommended dietary allowance requires data on the average requirement and the inter-individual variability of this requirement. However, no inter-individual variability values have been reported in the IAAO method. The aim of this study was thus to estimate the inter-individual variation in protein requirement using CPRM. From seven IAAO studies, the inter-individual variability was estimated as a coefficient of variation of about 20%. The coefficient of variation of the protein requirement determined by IAAO study was wider than the ordinary coefficient of variation obtained from the nitrogen balance test.

12.
PLoS One ; 15(12): e0240571, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33264296

RESUMEN

During development of the Caenorhabditis elegans gonad, the gonadal leader cells, called distal tip cells (DTCs), migrate in a U-shaped pattern to form the U-shaped gonad arms. The ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family metalloproteases MIG-17 and GON-1 are required for correct DTC migration. Mutations in mig-17 result in misshapen gonads due to the misdirected DTC migration, and mutations in gon-1 result in shortened and swollen gonads due to the premature termination of DTC migration. Although the phenotypes shown by mig-17 and gon-1 mutants are very different from one another, mutations that result in amino acid substitutions in the same basement membrane protein genes, emb-9/collagen IV a1, let-2/collagen IV a2 and fbl-1/fibulin-1, were identified as genetic suppressors of mig-17 and gon-1 mutants. To understand the roles shared by these two proteases, we examined the effects of the mig-17 suppressors on gon-1 and the effects of the gon-1 suppressors and enhancers on mig-17 gonadal defects. Some of the emb-9, let-2 and fbl-1 mutations suppressed both mig-17 and gon-1, whereas others acted only on mig-17 or gon-1. These results suggest that mig-17 and gon-1 have their specific functions as well as functions commonly shared between them for gonad formation. The levels of collagen IV accumulation in the DTC basement membrane were significantly higher in the gon-1 mutants as compared with wild type and were reduced to the wild-type levels when combined with suppressor mutations, but not with enhancer mutations, suggesting that the ability to reduce collagen IV levels is important for gon-1 suppression.


Asunto(s)
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiología , Movimiento Celular/genética , Desintegrinas/genética , Gónadas/crecimiento & desarrollo , Metaloendopeptidasas/genética , Proteínas ADAMTS/genética , Proteínas ADAMTS/metabolismo , Sustitución de Aminoácidos , Animales , Membrana Basal/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Colágeno Tipo IV/genética , Colágeno Tipo IV/metabolismo , Desintegrinas/metabolismo , Elementos de Facilitación Genéticos/genética , Regulación del Desarrollo de la Expresión Génica , Gónadas/citología , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Metaloendopeptidasas/metabolismo , Mutación
13.
BMC Musculoskelet Disord ; 20(1): 615, 2019 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-31878909

RESUMEN

BACKGROUND: Sarcopenia and osteoporosis reduce life quality and worsen prognosis in patients with liver cirrhosis (LC). When these two complications coexist, a diagnosis of osteosarcopenia is made. We aimed to investigate the actual situations of sarcopenia, osteoporosis, osteosarcopenia, and vertebral fracture, and to clarify the relationship among these events in patients with LC. METHODS: We describe a cross-sectional study of 142 patients with LC. Sarcopenia was defined according to the Japan Society of Hepatology (JSH) criteria, Asian Working Group for Sarcopenia (AWGS) criteria, and European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. The skeletal muscle mass index (SMI) and handgrip strength were assessed using bioelectrical impedance analysis and a digital grip strength dynamometer, respectively. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry, and vertebral fracture was evaluated using spinal lateral X-rays. The severity of LC was assessed using the Child-Pugh classification. RESULTS: Among the 142 patients, the prevalence of sarcopenia was 33.8% (48/142) according to the JSH and AWGS criteria and 28.2% (40/142) according to the EWGSOP2 criteria. The number of patients with osteoporosis, osteosarcopenia, and vertebral fracture was 49 (34.5%), 31 (21.8%), and 41 (28.9%), respectively. Multivariate analysis revealed a close association between sarcopenia and osteoporosis. Osteoporosis was independently associated with sarcopenia [odds ratio (OR) = 3.923, P = 0.010]. Conversely, sarcopenia was independently associated with osteoporosis (OR = 5.722, P < 0.001). Vertebral fracture occurred most frequently in patients with osteosarcopenia (19/31; 61.3%) and least frequently in those without both sarcopenia and osteoporosis (12/76; 15.8%). The SMI and handgrip strength values were significantly correlated with the BMD of the lumbar spine (r = 0.55 and 0.51, respectively; P < 0.001 for both), femoral neck, (r = 0.67 and 0.62, respectively; P < 0.001 for both), and total hip (r = 0.67 and 0.61, respectively; P < 0.001 for both). CONCLUSIONS: Sarcopenia, osteoporosis, osteosarcopenia, and vertebral fracture were highly prevalent and closely associated with one another in patients with LC. Specifically, patients with osteosarcopenia had the highest risk of vertebral fractures. Early diagnosis of these complications is essential for treatment intervention.


Asunto(s)
Cirrosis Hepática/complicaciones , Osteoporosis/epidemiología , Sarcopenia/epidemiología , Fracturas de la Columna Vertebral/epidemiología , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Japón/epidemiología , Cirrosis Hepática/epidemiología , Masculino , Persona de Mediana Edad , Osteoporosis/diagnóstico , Osteoporosis/etiología , Sarcopenia/diagnóstico , Sarcopenia/etiología , Fracturas de la Columna Vertebral/diagnóstico , Fracturas de la Columna Vertebral/etiología
14.
Org Lett ; 21(2): 461-464, 2019 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-30628796

RESUMEN

A one-pot synthesis of various 5,10-diaryl-5,10-dihydrophenazines (DADHPs) from diarylamines has been achieved by using an iron-catalyzed C-F amination. Homodimerization of magnesium diarylamides, followed by defluorinative intramolecular cyclization (double ortho C-F amination) in the presence of catalytic FeCl2 and stoichiometric 1,2-dibromoethane, affords the corresponding DADHPs with complete regiocontrol. The unique high reactivity of fluorine over other halogens indicates that amination proceeds via an SNAr mechanism facilitated by iron.

15.
Artículo en Inglés | MEDLINE | ID: mdl-33344956

RESUMEN

Introduction: One reason athletes train their trunk muscles is that the body's trunk stability has been shown to prevent injury. However, the relationship between body trunk muscle thickness, particularly that of deep muscles, and athletic performance remains to be clarified. Purpose: We aimed to explore the relationship between 100-m sprint performance and the sizes of the trunk stabilizing muscles, the psoas major muscle (PM), transversus abdominis (TA), and multifidus muscle (MM), in collegiate sprinters. Methods: Fourteen male sprinters belonging to a university athletics club participated in this study. The thicknesses of the TA and MM were measured using an ultrasonic diagnostic apparatus (ProSound C3; Aloka, Tokyo, Japan). The cross-sectional area of the PM was assessed by a magnetic resonance imaging apparatus (Vantage Elan; Toshiba Medical Systems, Tokyo, Japan). The relationship between these anthropometric parameters and the 100-m sprint time was analyzed by Spearman's correlation coefficient, multi- regression analysis, and the change-point regression model. Results: The sizes (mean ± SD) of the muscles were: PM, 43.074 ± 7.35 cm2; TA, 4.36 ± 0.72 mm; and MM, 3.99 ± 0.48 cm. The mean 100-m sprint time was 11.00 ± 0.48 s. Spearman's correlation analysis revealed that the 100-m sprint time had a significant moderate negative correlation with TA (ρ = -0.691, p < 0.01) and a low negative but not significant correlation with MM (ρ = -0.327, p = 0.28), whereas PM did not show a significant or in-negligible correlation. The change-point regression model found the change-points in the 100-m sprint time and the thickness of the TA and MM at 4.70 mm (95% CI: 4.00-5.43 mm) and 3.84 cm (95% CI: 3.28-4.31 cm), respectively. The sprint time decreased with an increase in the thickness of the muscles up to the change-points, whereas it did not change even if the muscles became thicker than the change-points. The change-points were consistently observed when the thickness of the muscles was normalized by body mass. Conclusion: Sprint performance for 100-m was found to be associated with TA and MM thickness in a biphasic manner. As muscle thickness increased, the sprint time decreased, followed by a plateau phase.

16.
Surg Case Rep ; 4(1): 133, 2018 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-30446840

RESUMEN

BACKGROUND: Thymic large cell neuroendocrine carcinoma (LCNEC) is extremely rare. The detailed clinical features of thymic LNCECs remain unknown. CASE PRESENTATION: A 90-year-old man with a history of diabetes mellitus, chronic renal failure, and an abdominal aortic aneurysm underwent computed tomography for follow-up, which showed an anterior mediastinal tumor, measuring 31 mm × 28 mm in diameter. Magnetic resonance imaging showed an iso-intensity mass on T1-weighted images and high intensity on T2-weighted images. 18F-Fluorodeoxyglucose-positron emission tomography showed marked uptake in the mass, which was diagnosed as invasive thymoma or thymic carcinoma. Video-assisted thoracic surgery through the left thoracic cavity was converted to median sternotomy due to severe adhesions between the left lung and the chest wall. Partial thymectomy and combined partial resection of left upper lobectomy and the first and the second costal cartilages were performed. The pathologic diagnosis was thymic LCNEC, Masaoka stage III. The patient developed pleural dissemination and left lung metastases in 5 months and died 12 months after surgery. CONCLUSIONS: Thymic LCNEC has high malignant potential. More cases need to be studied.

17.
Chem Commun (Camb) ; 54(80): 11276-11279, 2018 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-30238112

RESUMEN

We developed a practical chlorodifluoromethylation reaction mediated by diacyl peroxide generated in situ from chlorodifluoroacetic anhydride. Allylic and amino-chlorodifluoromethylations of alkenes proceeded well with the combination of this reagent, Cu(ii) catalyst and a pyridine additive. Carbo- and aromatic chlorodifluoromethylations proceeded under metal-free conditions.

18.
PLoS One ; 13(1): e0190635, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29293639

RESUMEN

There is increasing evidence for frequent turnover in sex chromosomes in vertebrates. Yet experimental systems suitable for tracing the detailed process of turnover are rare. In theory, homologous turnover is possible if the new sex-determining locus is established on the existing sex-chromosome. However, there is no empirical evidence for such an event. The genus Takifugu includes fugu (Takifugu rubripes) and its two closely-related species whose sex is most likely determined by a SNP at the Amhr2 locus. In these species, males are heterozygous, with G and C alleles at the SNP site, while females are homozygous for the C allele. To determine if a shift in the sex-determining locus occurred in another member of this genus, we used genetic mapping to characterize the sex-chromosome systems of Takifugu niphobles. We found that the G allele of Amhr2 is absent in T. niphobles. Nevertheless, our initial mapping suggests a linkage between the phenotypic sex and the chromosome 19, which harbors the Amhr2 locus. Subsequent high-resolution analysis using a sex-reversed fish demonstrated that the sex-determining locus maps to the proximal end of chromosome 19, far from the Amhr2 locus. Thus, it is likely that homologous turnover involving these species has occurred. The data also showed that there is a male-specific reduction of recombination around the sex-determining locus. Nevertheless, no evidence for sex-chromosome differentiation was detected: the reduced recombination depended on phenotypic sex rather than genotypic sex; no X- or Y-specific maker was obtained; the YY individual was viable. Furthermore, fine-scale mapping narrowed down the new sex-determining locus to the interval corresponding to approximately 300-kb of sequence in the fugu genome. Thus, T. niphobles is determined to have a young and small sex-determining region that is suitable for studying an early phase of sex-chromosome evolution and the mechanisms underlying turnover of sex chromosome.


Asunto(s)
Cromosomas Sexuales , Procesos de Determinación del Sexo , Takifugu/genética , Animales , Cruzamientos Genéticos , Femenino , Masculino , Filogenia , Polimorfismo de Nucleótido Simple , Sitios de Carácter Cuantitativo , Recombinación Genética
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