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1.
Front Endocrinol (Lausanne) ; 15: 1368944, 2024.
Article in English | MEDLINE | ID: mdl-38756997

ABSTRACT

Background: The 2022 World Health Organization (WHO) classification of pituitary neuroendocrine tumour (PitNET) supersedes the previous one in 2017 and further consolidates the role of transcription factors (TF) in the diagnosis of PitNET. Here, we investigated the clinical utility of the 2022 WHO classification, as compared to that of 2017, in a cohort of patients with non-functioning PitNET (NF-PitNET). Methods: A total of 113 NF-PitNET patients who underwent resection between 2010 and 2021, and had follow-up at Queen Mary Hospital, Hong Kong, were recruited. Surgical specimens were re-stained for the three TF: steroidogenic factor (SF-1), T-box family member TBX19 (TPIT) and POU class 1 homeobox 1 (Pit-1). The associations of different NF-PitNET subtypes with tumour-related outcomes were evaluated by logistic and Cox regression analyses. Results: Based on the 2022 WHO classification, the majority of NF-PitNET was SF-1-lineage tumours (58.4%), followed by TPIT-lineage tumours (18.6%), tumours with no distinct lineage (16.8%) and Pit-1-lineage tumours (6.2%). Despite fewer entities than the 2017 classification, significant differences in disease-free survival were present amongst these four subtypes (Log-rank test p=0.003), specifically between SF-1-lineage PitNET and PitNET without distinct lineage (Log-rank test p<0.001). In multivariable Cox regression analysis, the subtype of PitNET without distinct lineage (HR 3.02, 95% CI 1.28-7.16, p=0.012), together with tumour volume (HR 1.04, 95% CI 1.01-1.07, p=0.017), were independent predictors of a composite of residual or recurrent disease. Conclusion: The 2022 WHO classification of PitNET is a clinically useful TF and lineage-based system for subtyping NF-PitNET with different tumour behaviour and prognosis.


Subject(s)
Neuroendocrine Tumors , Pituitary Neoplasms , World Health Organization , Humans , Female , Male , Middle Aged , Pituitary Neoplasms/classification , Pituitary Neoplasms/pathology , Pituitary Neoplasms/metabolism , Neuroendocrine Tumors/pathology , Neuroendocrine Tumors/classification , Neuroendocrine Tumors/metabolism , Adult , Aged , Prognosis , Young Adult , Follow-Up Studies , T-Box Domain Proteins/metabolism
2.
Front Med (Lausanne) ; 10: 1246796, 2023.
Article in English | MEDLINE | ID: mdl-38116038

ABSTRACT

Here, we report the first adult case of pancreatic yolk sac tumor with ectopic adrenocorticotropic hormone (ACTH) syndrome. The patient was a 27-year-old woman presenting with abdominal distension, Cushingoid features, and hyperpigmentation. Endogenous Cushing's syndrome was biochemically confirmed. The ACTH level was in the normal range, which raised the suspicion of ACTH precursor-dependent disease. Elevated ACTH precursors were detected, supporting the diagnosis of ectopic ACTH syndrome. Functional imaging followed by tissue sampling revealed a pancreatic yolk sac tumor. The final diagnosis was Cushing's syndrome due to a yolk sac tumor. The patient received a steroidogenesis inhibitor and subsequent bilateral adrenalectomy for control of hypercortisolism. Her yolk sac tumor was treated with chemotherapy and targeted therapy. Cushing's syndrome secondary to a yolk sac tumor is extremely rare. This case illustrated the utility of ACTH precursor measurement in confirming an ACTH-related pathology and distinguishing an ectopic from a pituitary source for Cushing's syndrome.

4.
J Clin Endocrinol Metab ; 108(5): e76-e88, 2023 04 13.
Article in English | MEDLINE | ID: mdl-36453154

ABSTRACT

CONTEXT: Reports of thyroid dysfunction following COVID-19 vaccination included cases of relapse of Graves' disease and worsening of pre-existing Graves' disease. Little is known about the thyroid-specific outcomes among patients treated for hyperthyroidism who have received COVID-19 vaccination. OBJECTIVE: Among patients treated for hyperthyroidism, we evaluated factors associated with not receiving the COVID-19 vaccination and whether COVID-19 vaccination was associated with thyroid function instability. METHODS: We included consecutive patients treated for hyperthyroidism attending the thyroid clinic at a teaching hospital between January and September 2021. They were categorized into vaccinated and unvaccinated groups. The index date was the date of first-dose vaccination for the vaccinated group, and the first date of attendance in the inclusion period for the unvaccinated group. They were followed up until March 2022 or occurrence of thyroid function instability (worsening of thyroid function/increase in antithyroid drug dosage), whichever was earlier. RESULTS: A total of 910 patients were included (mean age 51.6 years; 82.1% female). Of these, 86.2% had Graves disease and 67.3% were vaccinated (67.3% BNT162b2; 30.6% CoronaVac; 2.1% heterologous). Abnormal thyroid function and cardiovascular comorbidities were independently associated with unvaccinated status. Upon median follow-up of 5.3 months, thyroid function instability occurred in 15.9% of patients. COVID-19 vaccination did not increase risks of thyroid function instability (hazard ratio 0.78, 95% CI 0.56-1.09, P = .151); this was consistent in Graves disease, both types of vaccines, and regardless of whether baseline thyroid function was normal. Twenty-seven patients overtly thyrotoxic at the time of vaccination received COVID-19 vaccines without triggering a thyroid storm or difficulty in subsequent thyroid function control. CONCLUSION: Among patients treated for hyperthyroidism, abnormal thyroid function was a factor predicting unvaccinated status. Our results should encourage patients treated for hyperthyroidism to receive COVID-19 vaccination to protect themselves from adverse outcomes and potential long-term sequelae of COVID-19.


Subject(s)
COVID-19 Vaccines , COVID-19 , Graves Disease , Hyperthyroidism , Female , Humans , Male , Middle Aged , BNT162 Vaccine , COVID-19/prevention & control , COVID-19/complications , Graves Disease/complications , Hyperthyroidism/complications , Vaccination
5.
Front Endocrinol (Lausanne) ; 13: 957369, 2022.
Article in English | MEDLINE | ID: mdl-35942178

ABSTRACT

The coexistence of insulinoma and type 2 diabetes is rare and the diagnostic process is often challenging. Continuous glucose monitoring system devices, which are more readily available nowadays, provide a useful tool for the diagnosis and evaluation of treatment response. Curative surgery is often the mainstay of treatment for insulinoma. Here, we report a Chinese patient with insulinoma diagnosed simultaneously with type 2 diabetes. His insulinoma was managed with endoscopic ultrasound guided-radiofrequency ablation (EUS-RFA) and the patient achieved complete resolution of hypoglycaemic episodes. The case illustrates that while EUS-RFA is an emerging non-invasive treatment modality for pancreatic lesions, limitations exist especially when histological confirmation is essential.


Subject(s)
Diabetes Mellitus, Type 2 , Insulinoma , Pancreatic Neoplasms , Radiofrequency Ablation , Blood Glucose , Blood Glucose Self-Monitoring , Diabetes Mellitus, Type 2/complications , Humans , Insulinoma/complications , Insulinoma/diagnostic imaging , Insulinoma/surgery , Pancreatic Neoplasms/complications , Pancreatic Neoplasms/diagnostic imaging , Pancreatic Neoplasms/surgery , Ultrasonography, Interventional
6.
Telemed J E Health ; 28(7): 920-931, 2022 07.
Article in English | MEDLINE | ID: mdl-34847758

ABSTRACT

Background: The purpose of this scoping review was to map the challenges, strategies, and lessons learned from high-income countries that can be mobilized to inform decision-makers on how to best implement virtual primary care services during and after the COVID-19 pandemic. Findings of our scoping review identified the barriers and strategies within the Quadruple Aim components, which may prove to be an effective implementation strategy for virtual care adoption in primary care settings. Materials and Methods:The two concepts of virtual care and COVID-19 were searched in MEDLINE, EMBASE, and CINAHL on August 10, 2020, and Scopus was searched on August 15, 2020. The database searches returned 10,549 citations and an additional 766 citations were retrieved from searching the citations from the reference lists of articles that met all inclusion criteria. A total of 1,260 full-text articles were reviewed of which 38 articles met the eligibility criteria for inclusion in the review. Results: Seven key barriers and strategies were identified for the implementation of virtual primary care. Of the 38 articles included, the key barriers identified were equitable access to care (n = 20; 53%), lack of funding for virtual care (n = 14; 37%), negative patient and clinician perception (n = 11, 29%), lack of regulatory policies (n = 10, 26%), inadequate clinical workflows (n = 9, 21), lack of virtual care infrastructure (n = 8, 21%), and insufficient virtual care training and education (n = 5, 13%). Strategies included the following: increased funding (n = 15, 39%), improving clinical workflows (n = 13, 34%), appropriate education and training (n = 11, 29%), improving virtual care infrastructure and patient equity (n = 7, 18%), establishing regulatory policies (n = 5, 13%), and improving patient and clinician perceptions (n = 3, 7%). Conclusions: As many countries enter potential subsequent waves of the COVID-19 pandemic, applying early lessons learned to mitigate implementation barriers can help with the transition to equitable and appropriate virtual primary care services.


Subject(s)
COVID-19 , Text Messaging , COVID-19/epidemiology , Developed Countries , Humans , Pandemics , Primary Health Care
7.
Endocr Pract ; 27(9): 894-902, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34237471

ABSTRACT

OBJECTIVE: Post-acute sequelae of coronavirus disease 2019 (COVID-19) or long COVID (LC) is an emerging global health issue. Fatigue is a common feature. Whether thyroid function and autoimmunity play a role is uncertain. We aimed to evaluate the prevalence and predictors of LC and the potential role of thyroid function and autoimmunity in LC. METHODS: We included consecutive adults without a known thyroid disorder who were admitted to a major COVID-19 center for confirmed COVID-19 from July to December 2020. Thyroid function tests and antithyroid antibodies were measured for all patients on admission and at follow-up. LC was defined by the presence or persistence of symptoms upon follow-up. RESULTS: In total, 204 patients (median age, 55.0 years; 95 men [46.6%]) were reassessed at a median of 89 days (interquartile range, 69-99) after acute COVID-19. Of the 204 patients, 41 (20.1%) had LC. Female sex (adjusted odds ratio, 2.48; P = .018) and severe acute respiratory syndrome coronavirus 2 polymerase chain reaction cycle threshold value of <25 on admission (adjusted odds ratio, 2.84; P = .012) independently predicted the occurrence of LC. Upon follow-up, most abnormal thyroid function tests in acute COVID-19 resolved, and incident thyroid dysfunction was rare. Nonetheless, we observed incident antithyroid peroxidase (anti-TPO) positivity. Although baseline or follow-up thyroid function tests were not associated with the occurrence of LC, among 172 patients with symptomatic acute COVID-19, symptom resolution was more likely in those with positive anti-TPO upon follow-up (P = .043). CONCLUSION: LC is common among COVID-19 survivors, with females and those with higher viral load in acute COVID-19 particularly being vulnerable. The observation of incident anti-TPO positivity warrants further follow-up for thyroid dysfunction. Whether anti-TPO plays a protective role in LC remains to be elucidated.


Subject(s)
Autoimmunity , COVID-19 , Adult , COVID-19/complications , Female , Humans , Male , Middle Aged , SARS-CoV-2 , Thyroid Gland , Post-Acute COVID-19 Syndrome
8.
Endocrinol Metab (Seoul) ; 36(3): 582-589, 2021 06.
Article in English | MEDLINE | ID: mdl-34107601

ABSTRACT

BACKGROUND: The occurrence of Graves' disease and Hashimoto thyroiditis after coronavirus disease 2019 (COVID-19) raised concerns that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may trigger thyroid autoimmunity. We aimed to address the current uncertainties regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors. METHODS: We included consecutive adult COVID-19 patients without known thyroid disorders, who were admitted to Queen Mary Hospital from July 21 to September 21, 2020 and had serum levels of thyroid-stimulating hormone, free thyroxine, free triiodothyronine (fT3), and anti-thyroid antibodies measured both on admission and at 3 months. RESULTS: In total, 122 patients were included. Among 20 patients with abnormal thyroid function tests (TFTs) on admission (mostly low fT3), 15 recovered. Among 102 patients with initial normal TFTs, two had new-onset abnormalities that could represent different phases of thyroiditis. Among 104 patients whose anti-thyroid antibody titers were reassessed, we observed increases in anti-thyroid peroxidase (TPO) (P<0.001) and anti-thyroglobulin (P<0.001), but not anti-thyroid stimulating hormone receptor titers (P=0.486). Of 82 patients with negative anti-TPO findings at baseline, 16 had a significant interval increase in anti-TPO titer by >12 U, and four became anti-TPO-positive. Worse baseline clinical severity (P=0.018), elevated C-reactive protein during hospitalization (P=0.033), and higher baseline anti-TPO titer (P=0.005) were associated with a significant increase in anti-TPO titer. CONCLUSION: Most patients with thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis occurred during convalescence, but infrequently. Importantly, our novel observation of an increase in anti-thyroid antibody titers post-COVID-19 warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.


Subject(s)
COVID-19/epidemiology , Survivors/statistics & numerical data , Thyroid Diseases/epidemiology , Thyroid Gland/immunology , Thyroid Gland/physiology , Adult , Autoimmunity/physiology , COVID-19/complications , COVID-19/immunology , China/epidemiology , Female , Follow-Up Studies , Humans , Male , Middle Aged , Patient Admission/statistics & numerical data , Prospective Studies , SARS-CoV-2/physiology , Thyroid Diseases/etiology , Thyroid Function Tests , Thyroiditis, Autoimmune/epidemiology , Thyroiditis, Autoimmune/etiology
9.
Clin Endocrinol (Oxf) ; 95(3): 469-477, 2021 09.
Article in English | MEDLINE | ID: mdl-33813743

ABSTRACT

OBJECTIVE: Existing studies reported the potential prognostic role of non-thyroidal illness syndrome (NTIS), characterized by low triiodothyronine (T3) with normal/low thyroid-stimulating hormone (TSH), mainly in severe COVID-19. None considered the significant impact of SARS-CoV-2 viral load on adverse outcomes. We aimed to clarify the prognostic role of NTIS among predominantly mild-to-moderate COVID-19 patients. DESIGN: A prospective study of COVID-19 patients. PATIENTS AND MEASUREMENTS: Consecutive adults admitted to Queen Mary Hospital for confirmed COVID-19 from July to December 2020 were prospectively recruited. SARS-CoV-2 viral load was represented by cycle threshold (Ct) values from real-time reverse transcription-polymerase chain reaction of the respiratory specimen on admission. Serum TSH, free thyroxine and free T3 were measured on admission. The outcome was deterioration in clinical severity, defined as worsening in ≥1 category of clinical severity according to the Chinese National Health Commission guideline. RESULTS: We recruited 367 patients. At baseline, 75.2% had mild disease, and 27 patients (7.4%) had NTIS. Fifty-three patients (14.4%) had clinical deterioration. Patients with NTIS were older, had more comorbidities, worse symptomatology, higher SARS-CoV-2 viral loads and worse profiles of inflammatory and tissue injury markers. They were more likely to have clinical deterioration (p < .001). In multivariable stepwise logistic regression analysis, NTIS independently predicted clinical deterioration (adjusted odds ratio 3.19, p = .017), in addition to Ct value <25 (p < .001), elevated C-reactive protein (p = .004), age >50 years (p = .011) and elevated creatine kinase (p = .017). CONCLUSIONS: Non-thyroidal illness syndrome was not uncommon even in mild-to-moderate COVID-19 patients. NTIS on admission could predict clinical deterioration in COVID-19, independent of SARS-CoV-2 viral load, age and markers of inflammation and tissue injury.


Subject(s)
COVID-19 , Euthyroid Sick Syndromes , Adult , Humans , Middle Aged , Prospective Studies , SARS-CoV-2 , Triiodothyronine , Viral Load
10.
J Clin Endocrinol Metab ; 106(2): e926-e935, 2021 01 23.
Article in English | MEDLINE | ID: mdl-33141191

ABSTRACT

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related thyroiditis is increasingly recognized. The role of thyroid autoimmunity and SARS-CoV-2 viral load in SARS-CoV-2-related thyroid dysfunction is unclear. We evaluated the thyroid function of a cohort of coronavirus disease 2019 (COVID-19) patients, in relation to their clinical features, and biochemical, immunological, and inflammatory markers. METHODS: Consecutive adult patients, without known thyroid disorders, admitted to Queen Mary Hospital for COVID-19 from July 21 to August 21, 2020, were included. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine, free triiodothyronine (fT3), and antithyroid antibodies were measured on admission. RESULTS: Among 191 patients with COVID-19 (mean age 53.5 ±â€…17.2 years; 51.8% male), 84.3% were mild, 12.6% were moderate, and 3.1% were severe. Abnormal thyroid function was seen in 13.1%. Ten patients had isolated low TSH, suggestive of subclinical thyrotoxicosis due to thyroiditis, although the contribution of autoimmunity was likely in 2 of them. Autoimmune thyroiditis probably also contributed to subclinical hypothyroidism in another patient. Ten patients had isolated low fT3, likely representing nonthyroidal illness syndrome. Lower SARS-Cov-2 polymerase chain reaction cycle threshold values and elevated C-reactive protein were independently associated with occurrence of low TSH (P = .030) and low fT3 (P = .007), respectively. A decreasing trend of fT3 with increasing COVID-19 severity (P = .032) was found. Patients with low fT3 had more adverse COVID-19-related outcomes. CONCLUSION: Around 15% of patients with mild to moderate COVID-19 had thyroid dysfunction. There may be a direct effect of SARS-CoV-2 on thyroid function, potentially leading to exacerbation of pre-existing autoimmune thyroid disease. Low fT3, associated with systemic inflammation, may have a prognostic significance.


Subject(s)
COVID-19/diagnosis , Immune System/physiology , Thyroid Diseases/diagnosis , Thyroid Diseases/immunology , Adult , Aged , Aged, 80 and over , COVID-19/complications , COVID-19/epidemiology , COVID-19/immunology , Cohort Studies , Euthyroid Sick Syndromes/complications , Euthyroid Sick Syndromes/diagnosis , Euthyroid Sick Syndromes/epidemiology , Euthyroid Sick Syndromes/immunology , Female , Humans , Immune System/physiopathology , Male , Middle Aged , Prognosis , SARS-CoV-2/physiology , Severity of Illness Index , Thyroid Diseases/complications , Thyroid Diseases/epidemiology , Thyroid Function Tests , Thyroid Gland/physiology , Thyroiditis, Autoimmune/complications , Thyroiditis, Autoimmune/diagnosis , Thyroiditis, Autoimmune/epidemiology , Thyrotoxicosis/complications , Thyrotoxicosis/diagnosis , Thyrotoxicosis/epidemiology , Thyrotoxicosis/immunology
11.
J Clin Microbiol ; 57(8)2019 08.
Article in English | MEDLINE | ID: mdl-31189582

ABSTRACT

An in-house-developed pncA sequencing assay for analysis of pyrazinamide (PZA) resistance was evaluated using 162 archived Mycobacterium tuberculosis complex (MTBC) isolates with phenotypic PZA susceptibility profiles that were well defined by analysis of Bactec MGIT 960 PZA kit and PZase activity data. Preliminary results showed 100% concordance between pncA sequencing and phenotypic PZA drug susceptibility test (DST) results among archived isolates. Also, 637 respiratory specimens were prospectively collected, and 158 were reported as MTBC positive by the Abbott Realtime MTB assay (96.3% sensitivity [95% confidence interval {CI}: 92.2% to 98.7%]; 100% specificity [95% CI: 99.2% to 100.0%]). Genotypic and phenotypic PZA resistance profiles of these 158 MTBC-positive specimens were analyzed by pncA sequencing and Bactec MGIT 960 PZA kit, respectively. For analysis of PZA resistance, pncA sequencing detected pncA mutations in 5/5 (100%) phenotypic PZA-resistant respiratory specimens within 4 working days. No pncA mutations were detected among PZA-susceptible specimens. Combining archived isolates with prospective specimens, 27 were identified as phenotypic PZA resistant with pncA mutation. Among these 27 samples, 6/27 (22.2%) phenotypic PZA-resistant strains carried novel pncA mutations without rpsA and panD mutations. These included 5 with mutations (a deletion [Del] at 383T [Del383T], Del 380 to 390, insertion of A [A Ins] at position 127, A Ins at position 407, and G Ins at position 508) in pncA structural genes and 1 with a mutation (T-12C) at the pncA promoter region. All six of these strains had no or reduced PZase activities, indicating that the novel mutations might confer PZA resistance. Additionally, 25/27 phenotypic PZA-resistant strains were confirmed multidrug-resistant tuberculosis (MDR-TB) strains. As PZA is commonly used in MDR-TB treatment regimens, direct pncA sequencing will rapidly detect PZA resistance and facilitate judicious use of PZA in treating PZA-susceptible MDR-TB.


Subject(s)
Amidohydrolases/genetics , Antitubercular Agents/pharmacology , Drug Resistance, Multiple, Bacterial/genetics , Mycobacterium tuberculosis/drug effects , Pyrazinamide/pharmacology , Algorithms , Biological Specimen Banks , Genotype , Humans , Microbial Sensitivity Tests , Mutation , Polymerase Chain Reaction , Reproducibility of Results , Sensitivity and Specificity , Sequence Analysis, DNA , Tuberculosis/microbiology
12.
Medicine (Baltimore) ; 98(17): e15296, 2019 Apr.
Article in English | MEDLINE | ID: mdl-31027093

ABSTRACT

RATIONALE: Deranged liver function is a common finding among patients with diabetes mellitus. We report a case of liver biopsy-proven glycogenic hepatopathy (GH) in a patient with long-standing poorly controlled type 1 diabetes (DM1), presented with recurrent transaminitis. PATIENT CONCERNS: A 28-year-old Chinese woman was noted to have deranged liver function with transaminases elevated to more than 15 times the upper limit of normal. DIAGNOSIS: She had underlying long-standing poorly controlled DM1. Blood tests including hepatitis serology and autoimmune panel were negative. Liver biopsy confirmed the diagnosis of GH, showing an increase in glycogen deposition with intact liver parenchymal architecture, and no inflammation or significant fibrosis. INTERVENTIONS: Her glycemic control was optimized. OUTCOMES: Her transaminase levels normalized upon subsequent follow-up with improved glycemic control. LESSONS: GH is suspected when transaminase flare occurs in patients with poorly controlled DM1, usually with exaggerated hemoglobin A1c levels, especially after drug-induced, viral, autoimmune and metabolic liver diseases are excluded. The gold standard of diagnosis is liver biopsy. When diagnosis of GH is ascertained, the mainstay of treatment is to optimize glycemic control. Typically, the transaminases may become normal within days to months after improvement of glycemic control. Compared to non-alcoholic fatty liver disease, GH is associated with favorable prognosis and runs a benign course, making this differentiation clinically important.


Subject(s)
Diabetes Mellitus, Type 1/complications , Liver Diseases/etiology , Liver Diseases/physiopathology , Adult , Female , Humans , Liver Function Tests
13.
Tuberculosis (Edinb) ; 112: 120-125, 2018 09.
Article in English | MEDLINE | ID: mdl-30205964

ABSTRACT

OBJECTIVE: To perform a prospective evaluation on the diagnostic performance of an in-house developed, duplex nested IS6110 real-time Polymerase-Chain-Reaction (PCR) assay (IS6110-qPCR assay) for rapid pulmonary TB diagnosis. METHODS: A total of 503 sputum specimens were prospectively collected from July 2016 to November 2016. Diagnostic accuracy and optimal cut-off Cycle-threshold (Ct) value for IS6110-qPCR assay was determined by Receiver Operating Characteristic (ROC) curve. Using the optimal cut-off Ct, diagnostic performance of IS6110-qPCR assay was assessed with reference to both bacteriological and clinical information. Meanwhile, limit of detection (LOD) was calculated using Mycobacterium tuberculosis H37Rv as reference strain. RESULT: ROC curve analysis of IS6110-qPCR assay showed a high Area Under the Curve (AUC) value (0.948) with optimal Ct value at 24.140. Prospective analysis of IS6110-qPCR assay with cut-off Ct = 24.140 showed a high overall sensitivity and specificity of 97.2% and 99.7%, respectively. No cross reactivity was observed among all non-tuberculous mycobacteria specimens in this study. LOD analysis on MTB-spiked sputum showed an average detection limit of 5.0 CFU/mL at Ct = 23.18 (±SD, 0.57). CONCLUSION: IS6110-qPCR assay is a highly accurate and cost-effective assay developed for primary screening of suspected TB cases, which is particularly suitable for regions with limited resources but high TB burden.


Subject(s)
Bacteriological Techniques , DNA, Bacterial/genetics , Mycobacterium tuberculosis/genetics , Real-Time Polymerase Chain Reaction , Tuberculosis, Pulmonary/diagnosis , Bacteriological Techniques/standards , Calibration , Genetic Markers , Hong Kong , Humans , Predictive Value of Tests , Prospective Studies , Real-Time Polymerase Chain Reaction/standards , Reference Standards , Reproducibility of Results , Sputum/microbiology , Tuberculosis, Pulmonary/genetics , Tuberculosis, Pulmonary/microbiology , Workflow
14.
J Biol Chem ; 289(2): 848-67, 2014 Jan 10.
Article in English | MEDLINE | ID: mdl-24280225

ABSTRACT

The homologous hexameric AAA(+) proteins, Hsp104 from yeast and ClpB from bacteria, collaborate with Hsp70 to dissolve disordered protein aggregates but employ distinct mechanisms of intersubunit collaboration. How Hsp104 and ClpB coordinate polypeptide handover with Hsp70 is not understood. Here, we define conserved distal loop residues between middle domain (MD) helix 1 and 2 that are unexpectedly critical for Hsp104 and ClpB collaboration with Hsp70. Surprisingly, the Hsp104 and ClpB MD distal loop does not contact Hsp70 but makes intrasubunit contacts with nucleotide-binding domain 2 (NBD2). Thus, the MD does not invariably project out into solution as in one structural model of Hsp104 and ClpB hexamers. These intrasubunit contacts as well as those between MD helix 2 and NBD1 are different in Hsp104 and ClpB. NBD2-MD contacts dampen disaggregase activity and must separate for protein disaggregation. We demonstrate that ClpB requires DnaK more stringently than Hsp104 requires Hsp70 for protein disaggregation. Thus, we reveal key differences in how Hsp104 and ClpB coordinate polypeptide handover with Hsp70, which likely reflects differential tuning for yeast and bacterial proteostasis.


Subject(s)
Escherichia coli Proteins/chemistry , HSP70 Heat-Shock Proteins/chemistry , Heat-Shock Proteins/chemistry , Protein Structure, Tertiary , Saccharomyces cerevisiae Proteins/chemistry , Amino Acid Sequence , Binding Sites/genetics , Circular Dichroism , Electrophoresis, Polyacrylamide Gel , Endopeptidase Clp , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , HSP70 Heat-Shock Proteins/genetics , HSP70 Heat-Shock Proteins/metabolism , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Hot Temperature , Models, Molecular , Molecular Sequence Data , Mutation , Protein Binding , Protein Denaturation , Protein Structure, Secondary , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Scattering, Small Angle , Sequence Homology, Amino Acid , X-Ray Diffraction
15.
Cell ; 151(4): 778-793, 2012 Nov 09.
Article in English | MEDLINE | ID: mdl-23141537

ABSTRACT

It is not understood how Hsp104, a hexameric AAA+ ATPase from yeast, disaggregates diverse structures, including stress-induced aggregates, prions, and α-synuclein conformers connected to Parkinson disease. Here, we establish that Hsp104 hexamers adapt different mechanisms of intersubunit collaboration to disaggregate stress-induced aggregates versus amyloid. To resolve disordered aggregates, Hsp104 subunits collaborate noncooperatively via probabilistic substrate binding and ATP hydrolysis. To disaggregate amyloid, several subunits cooperatively engage substrate and hydrolyze ATP. Importantly, Hsp104 variants with impaired intersubunit communication dissolve disordered aggregates, but not amyloid. Unexpectedly, prokaryotic ClpB subunits collaborate differently than Hsp104 and couple probabilistic substrate binding to cooperative ATP hydrolysis, which enhances disordered aggregate dissolution but sensitizes ClpB to inhibition and diminishes amyloid disaggregation. Finally, we establish that Hsp104 hexamers deploy more subunits to disaggregate Sup35 prion strains with more stable "cross-ß" cores. Thus, operational plasticity enables Hsp104 to robustly dissolve amyloid and nonamyloid clients, which impose distinct mechanical demands.


Subject(s)
Amyloid/metabolism , Heat-Shock Proteins/chemistry , Heat-Shock Proteins/metabolism , Saccharomyces cerevisiae Proteins/chemistry , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Adenosine Triphosphate/metabolism , Animals , Endopeptidase Clp , Escherichia coli/metabolism , Escherichia coli Proteins/metabolism , Humans , Parkinson Disease/metabolism , Prions/metabolism , Protein Folding
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