This article systematically analyzes the historical evolution of the name， origin， medicinal parts， producing area， harvesting and processing， nature， flavor and efficacy of Piperis Longi Fructus by referring to the materia medica， medical books， and prescription books of past dynasties， combined with the relevant modern literature， in order to provide a basis for the development and utilization of famous classical formulas containing this herb. According to the herbal textual research， the name of Piper longum first appeared in Nanfang Caomuzhuang， and it also has other aliases such as Biboli， Halou， and Hujiaohua. Historically， the origin of Piperis Longi Fructus has been P. longum of the Piperaceae family. In ancient times， both the fruit and root were used as medicine， and since the Republic of China， the fruit has been mainly used as medicine. The medicinal part is the dried， nearly ripe or ripe fruit spikes. Piperis Longi Fructus is native to India and has been introduced into China since the Tang dynasty. In the Ming dynasty， Bencao Pinhui Jingyao clearly stated that the genuine producing area was "Duanzhou"， present-day Zhaoqing in Guangdong province. Nowadays， it is planted in Guangdong， Guangxi， Hainan， Yunnan and other regions. Historically and currently， harvesting occurs in autumn. The ancient processing method uniformly involved removing the stems， soaking in the sourest vinegar overnight， baking， and scraping off the peels and grains with a knife until clean. In modern times， impurities are removed， and it is dried in the sun and crushed when used. The properties， functions and applications of P. longum are basically the same in ancient and modern times. It tastes pungent， is warm in nature， and non-toxic. It has the effects of warming the middle-jiao to dispel cold， lowering Qi and relieving pain， and is used for cold pain in the epigastrium and abdomen， vomiting， diarrhea， chest pain， headache， and toothache. Based on the research results， it is recommended that when developing famous classical formulas containing Piperis Longi Fructus， the dried nearly ripe or ripe fruit spikes of P. longum should be used. If there are no clear processing requirements， it is recommended to use the raw products for medicinal use， and the specific processing methods can refer to the relevant requirements under Piperis Longi Fructus in the 2025 edition of the Pharmacopoeia of the People's Republic of China. If processing requirements such as soaking in vinegar and peeling are clearly specified， it is recommended to follow the ancient methods.

This article systematically analyzes the historical evolution of the name， origin， medicinal parts， producing area， harvesting and processing， nature， flavor and efficacy of Piperis Longi Fructus by referring to the materia medica， medical books， and prescription books of past dynasties， combined with the relevant modern literature， in order to provide a basis for the development and utilization of famous classical formulas containing this herb. According to the herbal textual research， the name of Piper longum first appeared in Nanfang Caomuzhuang， and it also has other aliases such as Biboli， Halou， and Hujiaohua. Historically， the origin of Piperis Longi Fructus has been P. longum of the Piperaceae family. In ancient times， both the fruit and root were used as medicine， and since the Republic of China， the fruit has been mainly used as medicine. The medicinal part is the dried， nearly ripe or ripe fruit spikes. Piperis Longi Fructus is native to India and has been introduced into China since the Tang dynasty. In the Ming dynasty， Bencao Pinhui Jingyao clearly stated that the genuine producing area was "Duanzhou"， present-day Zhaoqing in Guangdong province. Nowadays， it is planted in Guangdong， Guangxi， Hainan， Yunnan and other regions. Historically and currently， harvesting occurs in autumn. The ancient processing method uniformly involved removing the stems， soaking in the sourest vinegar overnight， baking， and scraping off the peels and grains with a knife until clean. In modern times， impurities are removed， and it is dried in the sun and crushed when used. The properties， functions and applications of P. longum are basically the same in ancient and modern times. It tastes pungent， is warm in nature， and non-toxic. It has the effects of warming the middle-jiao to dispel cold， lowering Qi and relieving pain， and is used for cold pain in the epigastrium and abdomen， vomiting， diarrhea， chest pain， headache， and toothache. Based on the research results， it is recommended that when developing famous classical formulas containing Piperis Longi Fructus， the dried nearly ripe or ripe fruit spikes of P. longum should be used. If there are no clear processing requirements， it is recommended to use the raw products for medicinal use， and the specific processing methods can refer to the relevant requirements under Piperis Longi Fructus in the 2025 edition of the Pharmacopoeia of the People's Republic of China. If processing requirements such as soaking in vinegar and peeling are clearly specified， it is recommended to follow the ancient methods.

ObjectivePancreatic ductal adenocarcinoma (PDAC) exhibits a limited response to current treatments due to its dense fibrotic stroma and highly immunosuppressive tumor microenvironment. In recent years, advancements in cellular immunotherapy, particularly chimeric antigen receptor macrophage (CAR-M) therapy, have offered new hope for pancreatic cancer treatment. Although CAR-M therapy demonstrates dual potential in directly killing tumor cells and remodeling the immune microenvironment, it still faces challenges such as complex in vitro preparation processes and low in vivo targeting and delivery efficiency. Therefore, developing strategies for efficient and targeted in vivo delivery of CAR genes has become crucial for overcoming current therapeutic limitations. This study aims to develop an orally administrable nano-gene delivery system for the targeted delivery of CAR genes to pancreatic tumor sites. MethodsCore nano-gene particles (PNP/pCAR) were constructed by loading plasmid DNA encoding CAR (pCAR) with cationic polypeptides (PNP). Subsequently, PNP/pCAR was surface-modified with β-glucan to prepare the targeted nanoparticles (βGlus-PNP/pCAR). The loading efficiency of PNP for pCAR was quantitatively assessed by gel retardation assay. The particle size, Zeta potential, morphology, and storage stability of PNP/pCAR were characterized using a Malvern particle size analyzer and transmission electron microscopy. At the cellular level, RAW 264.7 macrophages were selected. The cytotoxicity of PNP/pCAR was evaluated using the CCK-8 assay. The cellular uptake efficiency and lysosomal escape ability of the nanoparticles were assessed via flow cytometry and confocal microscopy. Transfection efficiency was quantitatively evaluated by detecting the expression of the reporter gene GFP using flow cytometry. At the in vivo level, an orthotopic pancreatic cancer mouse model was established. Cy7-labeled βGlus-PNP/pCAR nanoparticles were administered orally, and the fluorescence distribution in mice was dynamically monitored at 1, 2, 4, 8, and 16 h post-administration using a small animal in vivo imaging system. Forty-eight hours after oral gavage, the mice were euthanized, and pancreatic tumor tissues were collected for further analysis of intratumoral fluorescence signals using the imaging system. Additionally, βGlus-PNP/pCAR-GFP nanoparticles loaded with the reporter gene (GFP) were administered orally. Forty-eight hours post-administration, pancreatic tumor tissues were harvested to prepare frozen sections, and GFP expression was observed and analyzed under a fluorescence microscope. ResultsThe PNP carrier exhibited a high loading capacity for pCAR. The successfully prepared PNP/pCAR nanoparticles were regular spheres with a hydrodynamic diameter of approximately (120±10) nm and a Zeta potential of about +(6±1) mV. They maintained good structural stability after incubation in PBS buffer for 7 d. Cell experiments demonstrated that PNP/pCAR exhibited no significant cytotoxicity in RAW 264.7 cells while being efficiently internalized and effectively escaping lysosomal degradation. The transfection positive rate of PNP/pCAR-GFP in RAW 264.7 cells reached (25±3)%, surpassing that of Lipofectamine 2000-loaded pCAR-GFP (Lipo/pCAR-GFP), which was (20±1)%.In vivo experiments revealed that, compared to unmodified PNP/pCAR, βGlus-PNP/pCAR exhibited strongerin situ pancreatic tumor targeting ability after oral administration. Furthermore, oral administration of βGlus-PNP/pCAR-GFP resulted in significant GFP protein expression detectable within pancreatic tumor tissues. ConclusionThis study successfully constructed and validated an orally administrable, pancreatic cancer-targeting polypeptide-based nano-gene delivery system. It provides an important technological foundation in delivery systems and experimental basis for the subsequent development of in situ CAR-M-based therapeutic strategies for pancreatic cancer.

ObjectivePancreatic ductal adenocarcinoma (PDAC) exhibits a limited response to current treatments due to its dense fibrotic stroma and highly immunosuppressive tumor microenvironment. In recent years, advancements in cellular immunotherapy, particularly chimeric antigen receptor macrophage (CAR-M) therapy, have offered new hope for pancreatic cancer treatment. Although CAR-M therapy demonstrates dual potential in directly killing tumor cells and remodeling the immune microenvironment, it still faces challenges such as complex in vitro preparation processes and low in vivo targeting and delivery efficiency. Therefore, developing strategies for efficient and targeted in vivo delivery of CAR genes has become crucial for overcoming current therapeutic limitations. This study aims to develop an orally administrable nano-gene delivery system for the targeted delivery of CAR genes to pancreatic tumor sites. MethodsCore nano-gene particles (PNP/pCAR) were constructed by loading plasmid DNA encoding CAR (pCAR) with cationic polypeptides (PNP). Subsequently, PNP/pCAR was surface-modified with β-glucan to prepare the targeted nanoparticles (βGlus-PNP/pCAR). The loading efficiency of PNP for pCAR was quantitatively assessed by gel retardation assay. The particle size, Zeta potential, morphology, and storage stability of PNP/pCAR were characterized using a Malvern particle size analyzer and transmission electron microscopy. At the cellular level, RAW 264.7 macrophages were selected. The cytotoxicity of PNP/pCAR was evaluated using the CCK-8 assay. The cellular uptake efficiency and lysosomal escape ability of the nanoparticles were assessed via flow cytometry and confocal microscopy. Transfection efficiency was quantitatively evaluated by detecting the expression of the reporter gene GFP using flow cytometry. At the in vivo level, an orthotopic pancreatic cancer mouse model was established. Cy7-labeled βGlus-PNP/pCAR nanoparticles were administered orally, and the fluorescence distribution in mice was dynamically monitored at 1, 2, 4, 8, and 16 h post-administration using a small animal in vivo imaging system. Forty-eight hours after oral gavage, the mice were euthanized, and pancreatic tumor tissues were collected for further analysis of intratumoral fluorescence signals using the imaging system. Additionally, βGlus-PNP/pCAR-GFP nanoparticles loaded with the reporter gene (GFP) were administered orally. Forty-eight hours post-administration, pancreatic tumor tissues were harvested to prepare frozen sections, and GFP expression was observed and analyzed under a fluorescence microscope. ResultsThe PNP carrier exhibited a high loading capacity for pCAR. The successfully prepared PNP/pCAR nanoparticles were regular spheres with a hydrodynamic diameter of approximately (120±10) nm and a Zeta potential of about +(6±1) mV. They maintained good structural stability after incubation in PBS buffer for 7 d. Cell experiments demonstrated that PNP/pCAR exhibited no significant cytotoxicity in RAW 264.7 cells while being efficiently internalized and effectively escaping lysosomal degradation. The transfection positive rate of PNP/pCAR-GFP in RAW 264.7 cells reached (25±3)%, surpassing that of Lipofectamine 2000-loaded pCAR-GFP (Lipo/pCAR-GFP), which was (20±1)%.In vivo experiments revealed that, compared to unmodified PNP/pCAR, βGlus-PNP/pCAR exhibited strongerin situ pancreatic tumor targeting ability after oral administration. Furthermore, oral administration of βGlus-PNP/pCAR-GFP resulted in significant GFP protein expression detectable within pancreatic tumor tissues. ConclusionThis study successfully constructed and validated an orally administrable, pancreatic cancer-targeting polypeptide-based nano-gene delivery system. It provides an important technological foundation in delivery systems and experimental basis for the subsequent development of in situ CAR-M-based therapeutic strategies for pancreatic cancer.

Objective To analyze the spatiotemporal distribution characteristics of and trends in the disease burden of dengue fever in China from 2005 to 2024, so as to provide insights into formulation of dengue fever control strategies. Methods Data pertaining to dengue fever cases in China from 2005 to 2024 were retrieved from the Infectious Disease Reporting Information System of Chinese Center for Disease Control and Prevention, and city population, gross domestic product (GDP), GDP per capita, and consumer price index in China were captured from the China Statistical Yearbook, National Bureau of Statistics of China, the China City Statistical Yearbook, and bureaus of statistics in each city. The disability-adjusted life years (DALYs), years of life lost (YLLs), and years lived with disability (YLDs) due to dengue fever were calculated in China from 2005 to 2024. The direct and indirect economic burdens of dengue fever were estimated to calculate the total economic burden. The trends in the disease burden of dengue fever were estimated in China from 2005 to 2024 using a Joinpoint regression model with the software Joinpoint 4.9.0.0, and the average annual percent change (AAPC) and its 95% confidence interval (CI) were calculated. In addition, the DALYs rate and economic burden of dengue fever in China were subjected to global and local spatial autocorrelation analyses using the software ArcGIS 10.8. Results The gross DALYs due to dengue fever were 5 558 person-years in China from 2005 to 2024, and the DALYs of dengue fever increased from 36 person-years in 2005 to 899 person-years in 2024, with an increase of 23.97 folds. The average annual DALYs rate of dengue fever was 0.02 person-years/10⁵ in China during the 20-year study period from 2005 to 2024, and the DALYs rate peaked in 2014 (0.13 person-years/10⁵) and reduced during the COVID-19 pandemic from 2020 to 2022. YLDs were the main contributor of DALYs due to dengue fever in China from 2005 to 2024, with a total of 5 354 person-years, accounting for 96.33% (5 354 person-years/5 558 person-years) of the gross DALYs. The gross DALYs of dengue fever were 2 982 person-years among men (53.66%) and 2 575 person-years among women (46.34%) in China from 2005 to 2024, and high DALYs of dengue fever were measured among residents at ages of 15 to 30 years (1 639 person-years), 30 to 45 years (1 857 person-years), and 45 to 60 years (1 204 person-years), respectively, accounting for 84.56% (4 700 person-years/5 558 person-years) of total DALYs due to dengue fever in China. The total economic burden of dengue fever was estimated to be 612 million Yuan in China from 2005 to 2024, with an average annual economic burden of 30.584 million Yuan. The economic burden of dengue fever increased from 196 000 Yuan in 2005 to 121 million Yuan in 2024 in China, with an increase of 616.35 folds, and the per capita economic burden increased from 3 322.21 Yuan in 2005 to 4 940.01 Yuan in 2024, with an increase of 48.70%. Dengue fever cases were reported in 274 cities (counties) across 31 provinces (autonomous regions, municipalities) in China from 2005 to 2024, with relatively higher DALYs in Guangdong Province and Yunnan Province. Spatial autocorrelation analysis revealed that the disease burden of dengue fever appeared positive aggregation in Chinese cities (counties) from 2005 to 2024 (global Moran’s I = 0.045, Z = 2.24, P < 0.05), with high-high clusters mainly concentrated in the Pearl River Delta region in Guangdong Province and Xishuangbanna Dai Autonomous Prefecture and Pu’er City in Yunnan Province, and the total economic burden (global Moran’s I = 0.032, Z = 9.55, P < 0.001), per capita economic burden (global Moran’s I = 0.208, Z = 27.34, P < 0.001), and the proportion of total economic burdens in GDP in 2024 (global Moran’s I = 0.017, Z = 5.91, P < 0.001) all presented positive aggregation, with relatively higher total economic burdens mainly concentrated in Guangdong Province and Yunnan Province. Joinpoint regression analysis showed that the gross DALYs rates of dengue fever appeared an overall tendency towards a rise in China from 2005 to 2024 (AAPC = 16.24%, P = 0.029), and the DALYs rate presented an overall tendency towards a rise among both men (AAPC = 14.75%, P = 0.028) and women (AAPC = 14.93%, P = 0.037) during the study period. The per capita direct economic burden appeared an overall tendency towards a rise among dengue fever patients in China from 2005 to 2024 (AAPC = 2.16%, P = 0.012); however, there was no significant difference in the trends in the per capita indirect economic burden (AAPC = 0.46%, P = 0.470). In addition, the DALYs rate of dengue fever appeared a tendency towards a rise in 84.67% (232/274) of cities (counties) in China from 2005 to 2024, and the per capita economic burden appeared a tendency towards a rise in 85.40% (234/274) of cities (counties), while the DALYs rate and per capita economic burden of dengue fever appeared a tendency towards a rise in 77.01% (211/274) of cities (counties). Conclusions The disease burden of dengue fever significantly increased in China from 2005 to 2024. It is recommended to reinforce integrated dengue fever control in high-risk areas and among high-risk populations, and to improve the surveillance of imported dengue fever cases and vector control.

Effective symptom management can alleviate the physical and psychological distress experienced by patients with cancer, improve quality of life, and contribute to treatment adherence and improve clinical outcomes. However, most existing guidelines are developed for healthcare professionals, and patients and the public have limited access to standardized and comprehensible guidance on symptom management. To address this gap and to facilitate effective communication and shared decision-making, this study proposes the development of a patient version of the cancer symptom management guideline. The development process will adhere to the methodological framework recommended by the Guidelines International Network and the World Health Organization. The GRADE approach will be employed to assess the certainty of evidence and to formulate recommendations. In addition, the process will be informed by the Appraisal of Guidelines for Research and Evaluation Ⅱ (AGREE Ⅱ) instrument and the Reporting Items for Practice Guidelines in Healthcare-Public or Patient Versions of Guidelines (RIGHT-PVG). This protocol outlines the establishment of the guideline working group, the identification and prioritization of key questions, evidence retrieval and appraisal, and the formulation of recommendations, with the aim of ensuring methodological rigor and transparency in the development of the patient guideline and providing methodological reference for similar guideline initiatives.

OBJECTIVE To quantitatively assess the compatibility risk of commonly used intravenous drugs in intensive care unit （ICU） patients with severe pneumonia， and provide a reference for reducing the incidence of adverse events caused by incompatibility. METHODS The PASS clinical pharmacy management system was used to retrospectively collect the data of patients diagnosed with “severe pneumonia” in the ICU of Hebei General Hospital from January 2023 to June 2025， and the commonly used intravenous drugs and medication frequency were extracted. Based on authoritative databases such as Micromedex and Stabilis as well as relevant literature， the compatibility data of commonly used intravenous drugs with 0.9% Sodium chloride injection and 5% Glucose injection were summarized. The theoretical and actual compatibility risk values were calculated using formulas， and high-risk drugs were screened and the compatibility query table was drawn. RESULTS A total of 158 ICU patients with severe pneumonia were treated with 89 intravenous drugs， and 24 drugs with high compatibility risk were identified. The drug with the highest theoretical compatibility risk value was Amphotericin B for injection （risk value 146）， and the drug with the highest actual compatibility risk value was Propofol medium and long chain fat emulsion injection （risk value 8 740）. Among the 24 high-risk drugs， six drugs， namely Esomeprazole sodium for injection， Ambroxol hydrochloride injection， Midazolam injection， Methylprednisolone sodium succinate for injection， Furosemide injection， and Cefoperazone sodium and sulbactam sodium for injection， simultaneously ranked among the top 15 in both theoretical and actual compatibility risk rankings. Among 650 pairwise compatibility combinations of the 24 drugs， 24.62% were compatible， 11.23% were incompatible， 6.77% had conflicting evidence， and 57.38% had missing evidence. CONCLUSIONS This study quantitatively analyzed the medication safety of commonly used intravenous drugs in ICU patients with severe pneumonia， identified 24 drugs with high compatibility risk， and established a compatibility query table for high-risk drugs， which helps reduce the risk of ICU compatibility adverse events.

BACKGROUND:LncRNA-TNFRSF13C,an important factor in B cell development and function,is expressed in periodontal tissues of patients with periodontitis,but the specific mechanism is still unclear. OBJECTIVE:To investigate the mechanism of lncRNA-TNFRSF13C regulating miR-1246 on hypoxia-inducible factor 1α in periodontal cells. METHODS:Human periodontal ligament cells(hPDLCs)were treated with lipopolysaccharide and divided into group A(hPDLCs cell lines without transfection),group B(hPDLCs cell lines transfected with TNFRSF13C NC-siRNA),group C(hPDLCs cell lines transfected with TNFRSF13C-siRNA),group D(hPDLCs cell line transfected with miR-1246 mimics),group E(hPDLCs cell line transfected with miR-1246 siRNA),group F(hPDLCs cell line transfected with TNFRSF13C-siRNA+miR-1246 mimics),and group G(hPDLCs cell line transfected with TNFRSF13C-siRNA+miR-1246 siRNA).The relative expression of lncRNA-TNFRSF13C and miR-1246 in each group was detected by qRT-PCR.Cell counting kit-8 assay was used to detect cell viability.Apoptosis was detected by flow cytometry.Expression of hypoxia-inducible factor 1α and vascular endothelial growth factor proteins was detected by western blot.The correlation between lncRNA-TNFRSF13C and miR-1246 was analyzed by Pearson,and the targeting relationship was analyzed by dual-luciferase reporter assay. RESULTS AND CONCLUSION:There was no significant difference in human periodontal ligament cell activity,apoptosis rate and protein indexes between groups A and B(P>0.05).Compared with group B,hPDLCS cell activity in group C was increased,and apoptosis rate and the expression of hypoxia-inducible factor 1α and vascular endothelial growth factor proteins were decreased(P<0.05).Compared with group C,hPDLCS cell activity in group D was decreased,and apoptosis rate and the expression of hypoxia-inducible factor 1α and vascular endothelial growth factor proteins were increased(P<0.05).Compared with group D,the cell activity of group E was increased(P<0.05).The cell activity in group F was lower than that in group E,and the apoptosis rate was reduced in both groups E and F(P<0.05).Compared with group F,the cell activity of group G was increased,and the apoptosis rate and the expression of hypoxia-inducible factor 1α and vascular endothelial growth factor were decreased(P<0.05).LncRNA-TNFRSF13C was positively correlated with miR-1246(P<0.05).Compared with the TNFRSF13C-siRNA group,the fluorescence activity of miR-1246-wt in the TNFRSF13C-NC group was reduced(P>0.05);compared with the miR-1246-NC group,the fluorescence activities of hypoxia-inducible factor 1α-wt and vascular endothelial growth factor-wt in the miR-1246 mimics group were increased(P<0.05).To conclude,down-regulation of lncRNA-TNFRSF13C can promote the activity of periodontal cells treated with lipopolysaccharide,reduce apoptosis,and inhibit hypoxia-inducible factor 1α and vascular endothelial growth factor.The mechanism is related to the regulation of miR-1246 activity.

Background: Maturity-onset diabetes of the young (MODY) due to variants of hepatocyte nuclear factor 1-beta (HNF1β) (MODY5) has not been well studied in the Chinese population. This study aimed to estimate its prevalence and evaluate the application of a clinical screening method (Faguer score) in Chinese early-onset diabetes (EOD) patients. Methods: Among 679 EOD patients clinically diagnosed with type 2 diabetes mellitus (age at diagnosis ≤40 years), the exons of HNF1β were sequenced. Functional impact of rare variants was evaluated using a dual-luciferase reporter system. Faguer scores ≥8 prompted multiplex ligation-dependent probe amplification (MLPA) for large deletions. Pathogenicity of HNF1β variants was assessed following the American College of Medical Genetics and Genomics (ACMG) guidelines. Results: Two rare HNF1β missense mutations (E105K and G454R) were identified by sequencing in five patients, showing functional impact in vitro. Another patient was found to have a whole-gene deletion by MLPA in 22 patients with the Faguer score above 8. Following ACMG guidelines, six patients carrying pathogenic or likely pathogenic variant were diagnosed with MODY5. The estimated prevalence of MODY5 in Chinese EOD patients was approximately 0.9% or higher. Conclusion MODY5 is not uncommon in China. The Faguer score is helpful in deciding whether to perform MLPA analysis on patients with negative sequencing results.

Background: Maturity-onset diabetes of the young (MODY) due to variants of hepatocyte nuclear factor 1-beta (HNF1β) (MODY5) has not been well studied in the Chinese population. This study aimed to estimate its prevalence and evaluate the application of a clinical screening method (Faguer score) in Chinese early-onset diabetes (EOD) patients. Methods: Among 679 EOD patients clinically diagnosed with type 2 diabetes mellitus (age at diagnosis ≤40 years), the exons of HNF1β were sequenced. Functional impact of rare variants was evaluated using a dual-luciferase reporter system. Faguer scores ≥8 prompted multiplex ligation-dependent probe amplification (MLPA) for large deletions. Pathogenicity of HNF1β variants was assessed following the American College of Medical Genetics and Genomics (ACMG) guidelines. Results: Two rare HNF1β missense mutations (E105K and G454R) were identified by sequencing in five patients, showing functional impact in vitro. Another patient was found to have a whole-gene deletion by MLPA in 22 patients with the Faguer score above 8. Following ACMG guidelines, six patients carrying pathogenic or likely pathogenic variant were diagnosed with MODY5. The estimated prevalence of MODY5 in Chinese EOD patients was approximately 0.9% or higher. Conclusion MODY5 is not uncommon in China. The Faguer score is helpful in deciding whether to perform MLPA analysis on patients with negative sequencing results.