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PubMed2001

Impact of multidetector CT on donor selection and surgical planning before living adult right lobe liver transplantation.

OBJECTIVE: This study was performed to document the impact of multidetector multiphase CT in facilitating patient selection and surgical planning in potential donors being evaluated for living adult right lobe liver transplantation. SUBJECTS AND METHODS: Forty consecutive potential donors were included in the study. There were 26 men and 14 women, (age range, 18-57 years; mean, 37 years) We performed CT using a multidetector scanner, after IV injection of 180 mL of contrast material at 5 mL/sec. Arterial phase images were acquired at 18 sec (collimation, 1.25 mm; table speed, 7.5) and portal phase images, at 60 sec (collimation, 2.5 mm; table speed, 15). Postprocessing was performed on a commercially available workstation. CT data included dual-energy assessment of liver parenchyma for fatty infiltration; depiction of arterial, portal venous, and hepatic venous anatomy and identification of important vascular variants; and determination of total and lobar liver volume. RESULTS: Of the 40 potential liver donors evaluated, 15 patients (37.5%) were excluded on the basis of CT findings, with most exclusions a result of portal vein anomalies (n = 8). Fatty infiltration resulted in four exclusions (10%), and small liver volume resulted in three exclusions (7.5%). CONCLUSION: Multidetector multiphase CT provided comprehensive parenchymal, vascular, and volumetric preoperative evaluation of potential donors undergoing living adult right lobe liver transplantation. This information had a major impact on patient selection because it was used to stratify patients. It allowed the surgeons to plan their surgical approach, and this planning may reduce postoperative complications.

Adolescent↗
PubMed2002

Using multidetector CT for preoperative vascular evaluation of liver neoplasms: technique and results.

OBJECTIVE: The purpose of our study was to evaluate the performance of CT angiography using multidetector CT (MDCT) for preoperative vascular evaluation in candidates who were scheduled for liver neoplasm resection. SUBJECTS AND METHODS: Forty-two consecutive subjects with malignant liver tumors scheduled for resection were studied with multiphase MDCT. The first 22 subjects underwent both multiphase MDCT angiography and catheter angiography before surgery. The subsequent 20 subjects underwent only preoperative CT angiography. Postprocessing was performed, and the images were analyzed for the depiction of arterial, portal vein, and hepatic vein anatomy and for the identification of important vascular variants. The postprocessing findings were compared and correlated with the findings from catheter angiography (22/42) or intraoperative sonography (42/42) and surgery (42/42). RESULTS: Arterial anomalies were detected on the images of 17 of 42 patients, including a replaced right hepatic artery in five, replaced left hepatic artery in six, accessory right and left hepatic arteries in two, common trunk for the celiac and superior mesenteric arteries in one, and early bifurcation of the celiac artery in one. In 22 patients in whom catheter angiography confirmation was available, the number of arteries and almost all the significant anomalies were correctly identified on CT angiography (accuracy, 97%; sensitivity, 94%; specificity, 100%). In the subset of 20 patients who underwent MDCT angiography without catheter angiography confirmation, all clinically relevant information was provided by CT angiography. The portal and hepatic vein anatomy and the relationships of the liver tumors to the neighboring venous structures were shown on CT. CONCLUSION: Multidetector CT provides valuable preoperative information about hepatic vascular architecture and can be used as a noninvasive alternative to catheter angiography before oncologic liver surgery.

Adult↗
PubMed1999

Identification and functional analysis of novel human melanocortin-4 receptor variants.

Inactivation of the melanocortin-4 receptor (MC4-R) by gene-targeting results in mice that develop maturity-onset obesity, hyperinsulinemia, and hyperglycemia. These phenotypes resemble common forms of human obesity, which are late-onset and frequently accompanied by NIDDM. It is not clear whether sequence variation of the MC4-R gene contributes to obesity in humans. Therefore, we examined the human MC4-R gene polymorphism in 190 individuals ascertained on obesity status. Three allelic variants were identified, including two novel ones, Thr112Met and Ile137Thr. To analyze possible functional alterations, the variants were cloned and expressed in vitro and compared with the wild-type receptor. One of the novel variants, Ile137Thr, identified in an extremely obese proband (BMI 57), was found to be severely impaired in ligand binding and signaling, raising the possibility that it may contribute to development of obesity. Furthermore, our results also suggest that sequence polymorphism in the MC4-R coding region is unlikely to be a common cause of obesity in the population studied, given the low frequency of functionally significant mutations.

Adolescent↗
PubMed1996

Insight into the genetic epidemiology of coronary heart disease.

The associations between candidate gene polymorphisms and coronary heart disease (CHD) are complex as a consequence of pleiotropy, variation with age, selection due to the high lethality of the disease, and interactions with other genes and with environmental factors. Identification of the gene variants that contribute to CHD appears possible; this may considerably improve our understanding of the aetiology and mechanisms of this disease. Furthermore, simultaneous analysis of several predisposing alleles may help to identify high-risk individuals.

Alcohol Drinking↗
PubMed2026

Genetic associations in sepsis and ARDS.

Critical illness syndromes, such as sepsis and acute respiratory distress syndrome (ARDS), are characterized by substantial clinical heterogeneity and remain major causes of morbidity and mortality worldwide. Increasing evidence suggests that genetic variation contributes to susceptibility, disease severity, and clinical outcomes in critically ill patients. However, the molecular mechanisms linking genetic predisposition to the pathophysiology of sepsis and ARDS remain incompletely understood. In this review, we evaluated genetic associations reported in sepsis and ARDS, including 13 genome-wide studies identifying 19 unique single-nucleotide polymorphisms (SNPs) across 17 distinct genomic loci, as well as 21 meta-analyses of candidate-gene studies identifying 21 SNPs across 16 genes. The identified variants were primarily associated with pathways involved in pathogen recognition, immune and inflammatory signaling, leukocyte recruitment, and endothelial dysfunction. Collectively, these findings support a polygenic basis for susceptibility to critical illness and highlight several biologically relevant pathways that may contribute to sepsis and ARDS pathogenesis. Improved understanding of the functional consequences of these variants may facilitate the identification of potential therapeutic targets and support the development of precision-guided approaches to critical care.

ARDS↗
PubMed2001

The HA-2 minor histocompatibility antigen is derived from a diallelic gene encoding a novel human class I myosin protein.

Human minor histocompatibility Ags (mHag) present significant barriers to successful bone marrow transplantation. However, the structure of human mHag and the basis for antigenic disparities are still largely unknown. Here we report the identification of the gene encoding the human mHag HA-2 as a previously unknown member of the class I myosin family, which we have designated MYO1G. The gene is located on the short arm of chromosome 7. Expression of this gene is limited to cells of hemopoietic origin, in keeping with the previously defined tissue expression of the HA-2 Ag. RT-PCR amplification of MYO1G from different individuals led to the identification of two genetic variants, designated MYO1G(V) and MYO1G(M). The former encodes the peptide sequence previously shown to be the HA-2 epitope (YIGEVLVSV), whereas the latter shows a single amino acid change in this peptide (YIGEVLVSM). This change has only a modest effect on peptide binding to the class I MHC-restricted element HLA-A*0201, and a minimal impact on recognition by T cells when added exogenously to target cells. Nonetheless, as detected using either T cells or mass spectrometry, this amino acid change results in a failure of the latter peptide to be presented at the surface of cells that express MYO1G(M) endogenously. These studies have thus identified a new mHag-encoding gene, and thereby provide additional information about both the genetic origins of human mHag as well as the underlying basis of an Ag-positive vs Ag-negative state.

Alleles↗
PubMed1999

Evaluation of a fully automated high-performance liquid chromatography assay for hemoglobin A1c.

INTRODUCTION: Measurement of hemoglobin A1c (HbA1c) is used as an objective measure of long-term blood glucose control in diabetic patients. Recent improvements in automation combined with new recommendations for precision and accuracy have caused us to reevaluate our methods for measuring HbA1c. OBJECTIVE: We evaluated a newly automated high-performance liquid chromatography (HPLC) instrument for measurement of HbA1c (Tosoh A1c 2.2 Plus Glycohemoglobin Analyzer, Tosoh Medics, Foster City, Calif) and compared the results obtained by HPLC to those obtained with an immunoassay (Hitachi 911, Boehringer Mannheim Corporation, Indianapolis, Ind). RESULTS: The Tosoh analyzer was found to be linear in a range of 5.3% to 17% and had a throughput of 20 samples per hour. HbA1c results for 102 patient samples by the 2 techniques showed good correlation, with a slope of 0.87 and an intercept at 1.27% +/- 0.15%. Both the total and within-run coefficients of variation were consistently lower for the HPLC method compared with the immunoassay method. The HPLC method produces a chromatogram that shows the different hemoglobin fractions, allowing identification of abnormal hemoglobin variants. In heterozygous individuals, HbA1c measurements are made with no interference from the hemoglobin variant. In the case of homozygous or doubly heterozygous hemoglobin variants, the Tosoh HPLC identifies the hemoglobin variants as such and correctly does not report a HbA1c value in the presence of a markedly decreased amount of hemoglobin A. CONCLUSIONS: The Tosoh HPLC provides adequate throughput and improved precision, and the method is traceable to the Diabetes Control and Complications Trial.

Chromatography, High Pressure Liquid↗
PubMed1998

Epidemiology of human rabies in the United States, 1980 to 1996.

PURPOSE: To summarize the epidemiologic, diagnostic, and clinical features of the 32 laboratory-confirmed cases of human rabies diagnosed in the United States from 1980 to 1996. DATA SOURCES: Data were obtained from case reports of human rabies submitted to the Centers for Disease Control and Prevention by state or local health authorities. STUDY SELECTION: All cases of human rabies reported in the United States from 1980 to 1996 in which infection with rabies virus was confirmed by laboratory studies. DATA EXTRACTION: Patients were reviewed for demographic characteristics, exposure history, rabies prophylaxis, clinical presentation, treatment, clinical course, diagnostic laboratory tests, identification of rabies virus variants, and the number of medical personnel or family members who required postexposure prophylaxis after coming in contact with an exposed person. DATA SYNTHESIS: 32 cases of human rabies were reported from 20 states. Patients ranged in age from 4 to 82 years and were predominantly male (63%). Most patients (25 of 32) had no definite history of an animal bite or other event associated with rabies virus transmission. Of the 32 cases, 17 (53%) were associated with rabies virus variants found in insectivorous bats, 12 (38%) with variants found in domestic dogs outside the United States, 2 (6%) with variants found in indigenous domestic dogs, and 1 (3%) with a variant found in indigenous skunks. Among the 7 patients with a definite exposure history, 6 cases were attributable to dog bites received in foreign countries and 1 was attributable to a bat bite received in the United States. In 12 of the 32 patients (38%), rabies was not clinically suspected and was diagnosed after death. In the remaining 20 cases (63%), the diagnosis of rabies was considered before death and samples were obtained specifically for laboratory confirmation a median of 7 days (range, 3 to 17 days) after the onset of clinical signs. Of the clinical differences between patients in whom rabies was diagnosed before death and those in whom it was diagnosed after death, the presence of hydrophobia or aerophobia was significantly associated with antemortem diagnosis (odds ratio, 11.0 [95% CI, 1.05 to 273.34]). The median number of medical personnel or familial contacts of the patients who received postexposure prophylaxis was 54 per patient (range, 4 to 179). None of the 32 patients with rabies received postexposure prophylaxis before the onset of clinical disease. CONCLUSIONS: In the United States, human rabies is rare but probably underdiagnosed. Rabies should be included in the differential diagnosis of any case of acute, rapidly progressing encephalitis, even if the patient does not recall being bitten by an animal. In addition to situations involving an animal bite, a scratch from an animal, or contact of mucous membranes with infectious saliva, postexposure prophylaxis should be considered if the history indicates that a bat was physically present, even if the person is unable to reliably report contact that could have resulted in a bite. Such a situation may arise when a bat bite causes an insignificant wound or the circumstances do not allow recognition of contact, such as when a bat is found in the room of a sleeping person or near a previously unattended child.

Age Distribution↗
PubMed1999

[Molecular study of red cell pyruvate kinase deficiency in 15 patients with chronic hemolytic anemia. Group of Erythropathology of Hematology and hemotherapy Association of Spain (HHAS)].

BACKGROUND: Identification of RBC pyruvate-kinase (PK) gene mutations by polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP) followed by PK gene sequencing in positive cases has been assessed and the results obtained with a preliminary study of 15 unrelated patients of Spanish origin are presented. PATIENTS AND METHODS: Patients have been classified into two different groups: group 1, propositus (15 cases), and group 2, relatives of the patients included in group 1 (10 males and 5 females). In group 1, a PCR was followed by SSCP and sequencing, and in group 2, the PCR was followed by digestion with specific restriction endonucleases (PCR-ER). RESULTS: Group 1: from 15 patients included in the study 2 were identified as homozygous, 4 as heterozygous and 9 as compound heterozygous. In this group, were identify 26 affected alleles with 11 different mutations: T1456 10 alleles (38.6%), T721 3 alleles (11.6%), A1010, C514, C1015 and T1223 2 alleles (7.7%), and C1070, A1291, T1508, A1595 y T1675 one allele. Relatives from 8 out of 15 patients from group 1 showed the following pattern: homozygous (one case), heterozygous (10 cases), compound heterozygous (2 cases) and normal (2 cases). CONCLUSIONS: SSCP procedure followed by direct gene sequencing in positive cases is fast and simple enough to allow the identification of PK deficient variants, avoiding the need of biochemical characterisation of semipurified deficient enzyme, which is more cumbersome and time consuming. In addition, the PCR-ER method is a very useful tool for screening of the most frequent molecular variants, as well as, for the detection of the carrier condition of this enzymopathy (family studies).

Amino Acids↗
PubMed2000

Variations of the superficial middle cerebral vein: classification using three-dimensional CT angiography.

BACKGROUND AND PURPOSE: Classification of variations of the superficial middle cerebral vein (SMCV) remains ambiguous. We propose a new classification system based on embryologic development for preoperative examination. METHODS: Three-dimensional CT angiography was used to evaluate 500 SMCVs (in 250 patients). The outflow vessels from the SMCV were classified into seven types on the basis of embryologic development. The 3D CT angiograms in axial stereoscopic and oblique views and multiple intensity projection images were evaluated by the same neurosurgeon on two occasions. Inconsistent interpretations were regarded as equivocal. RESULTS: Three-dimensional CT angiography clearly depicted the SMCV running along the lesser wing or the middle cranial fossa. However, the outflow vessel could not be confirmed as the sphenoparietal, cavernous, or emissary type in 39 (8%) of the sides. SMCVs running in the middle cranial fossa to join the transverse sinus or superior petrosal sinus were accurately identified. SMCVs were present in 456 sides: 62% entered the sphenoparietal sinus or the cavernous sinus and 12% joined the emissary vein. Nine vessels were the superior petrosal type, 10 the basal type, 12 the squamosal type, and 44 the undeveloped type. CONCLUSION: Three-dimensional CT angiography can depict the vessels and their anatomic relationship to the bone structure, allowing identification of the SMCV variant in individual patients. Preoperative planning for skull base surgery requires such information to reduce the invasiveness of the procedure. With the use of our classification system, 3D CT angiography can provide exact and practical information concerning the SMCV.

Adult↗
PubMedDate not supplied

[Sleep disorders associated to prion diseases].

INTRODUCTION: Description of sleep disorders associated to human prion diseases. DEVELOPMENT: The recent advances on pathology, genetics and immunocytochemistry are an outstanding contribution to the knowledge of transmissible spongiform encephalopathies and identification of possible new variants. Despite decades of research, human prion diseases have remained enigmatic in many aspects. Among these, the intricate connection between infectivity and genetics, genotype-phenotype correlation, pathogenesis of brain damage and in some cases its proven dependence on the genotypic combination of a pathogenic mutation and a polymorphism. Regarding this subject we should take into consideration that Fatal Familial Insomnia (FFI) appears as an ideal model situation for answering some of these problems because of its distinctive clinicopathological phenotype based on a specific genotype as well as its transmissibility. This disease has recently enlarged the group of prion diseases. It is linked to a mutation at codon 178 of the prion protein gene, coupled with the methionine codon at position 129, the site of a methionine/valine polymorphism. The clinical aspects of FFI include a peculiar sleep-wake disorder and a autonomic hyperactivity associated with vegetative and hormonal circadian rhythm disregulation, besides cognitive and motor alteration, and it is related to the selective atrophy of limbic part of the thalamus. EEG conventional sleep studies and 24-hour polygraphic recordings can provide proof of early disappearance sleep spindles and the disturbances of sleep, which typify the disease. Epidemiologic, pathophysiologic, and histopathological aspects are also mentioned. Finally we remark the major neurophysiological features of Creutzfeldt-Jakob disease and Morvan's chorea.

Atrophy↗
PubMed2001

Long-term evaluation of electrospray ionization mass spectrometric analysis of glycated hemoglobin.

BACKGROUND: Electrospray ionization mass spectrometry (ESIMS) has been successfully applied to the identification of hemoglobin (Hb) variants and the presence of glucose adducts (mass difference of 162 Da) on the separate Hb alpha and beta chains. To establish the potential of ESIMS as a routine and/or a reference method for the quantification of glycohemoglobin (HbA1c), we carried out a detailed evaluation over a 4-month period in a routine laboratory environment. METHODS: We optimized a procedure using ESIMS suitable for the routine quantitative analysis of HbA1c. We determined reliability and reproducibility over 4 months and assessed the potential for automated sample injection. We then compared values of 1022 blood samples from diabetic patients with a routine HPLC-based ion-exchange procedure (HA-8140; Menarini). RESULTS: Results of HbA1c measurement by ESIMS were available within 3 min. The analytical imprecision (CV) was 1.6-5.0% for both manual and automated injections. Data collection over the m/z 980-1400 range confirmed lower glycation of the alpha chain relative to the beta chain (0.66:1). Only one glycation was observed per globin chain. The overall glycohemoglobin (i.e., the average of alpha- and beta-chain glycations) measured by ESIMS (x) on 1022 blood samples was lower than by HPLC (y): y = 1.0432x + 0.4815. However, the ss-chain glycation measured by ESIMS was up to 20% higher than the value measured by ion-exchange HPLC and showed a close conformity, particularly at 5-10% HbA1c, with the ion-exchange Diabetes Control and Complications Trial (DCCT)-corrected and the United Kingdom National External Quality Assessment Scheme DCCT mean return values. CONCLUSIONS: ESIMS provides a precise measurement of HbA1c and, in particular, glycation of the beta chain. The method is robust and could be proposed as a procedure to substantiate HbA1c measurement and/or calibration.

Autoanalysis↗
PubMed2002

Mutations in the dopamine beta-hydroxylase gene are associated with human norepinephrine deficiency.

Norepinephrine (NE), a key neurotransmitter of the central and peripheral nervous systems, is synthesized by dopamine beta-hydroxylase (DBH) that catalyzes oxidation of dopamine (DA) to NE. NE deficiency is a congenital disorder of unknown etiology, in which affected patients suffer profound autonomic failure. Biochemical features of the syndrome include undetectable tissue and circulating levels of NE and epinephrine, elevated levels of DA, and undetectable levels of DBH. Here, we report identification of seven novel variants including four potentially pathogenic mutations in the human DBH gene (OMIM 223360) from analysis of two unrelated patients and their families. Both patients are compound heterozygotes for variants affecting expression of DBH protein. Each carries one copy of a T-->C transversion in the splice donor site of DBH intron 1, creating a premature stop codon. In patient 1, there is a missense mutation in DBH exon 2. Patient 2 carries missense mutations in exons 1 and 6 residing in cis. We propose that NE deficiency is an autosomal recessive disorder resulting from heterogeneous molecular lesions at DBH.

Animals↗
PubMedDate not supplied

[Sporadic Creutzfeldt-Jakob disease: phenotypic variability].

Prion disease are characterized by cerebral deposition of an abnormal protease-resistant isoform of a membrane-bound glycoprotein called prion protein. Sporadic Creutzfeldt-Jakob disease (CJDs) is the most frequent, accounting for approximately 85% of all human prion disease. The identification of a new variant of Creutzfeldt-Jakob disease has reinforced the need for a detailed analysis of phenotypic variability of CJDs. CJDs is typically characterized by rapidly progressive dementia, myoclonus, periodic sharp-wave electroencephalographic activity, and wide-spread spongiform degeneration. However, variations in clinical presentation, disease duration, as well as type and distribution of lesion have been consistently observed. The physicochemical properties of PrPsc in conjunction with the PRNP codon 129 genotype largely determine this phenotypic variability. Continued attention to clinically atypical cases is required to monitor the real incidence of CJDs. To reach this goal neuropathological examination, including the search for PrPsc, and molecular genetic analysis of human prion protein gene (PRNP) should be increasingly applied to atypical neurodegenerative diseases.

Adult↗
PubMed1992

Lack of prognostic value of histopathologic parameters in Hodgkin's disease, nodular sclerosis type. A study of 123 patients with limited stage disease who had undergone laparotomy and were treated with radiation therapy.

The value of histopathologic parameters in predicting the long-term overall survival probabilities was studied in a series of 123 patients with pathologic stage IA, IB, IIA, IIB, or IIIA Hodgkin's disease, nodular sclerosis type who were treated with curative radiation therapy. The parameters that were studied included the relative proportion of atypical vs reactive cells, amount of eosinophils, presence of necrosis, degree of mitotic activity, intensity of different types of mesenchymal reactions, classification in three subtypes (ie, lymphocyte predominance, mixed cellularity, and lymphocyte depletion) or in two grades (ie, grades 1 and 2), and identification of the syncytial variant. For each parameter, the association with clinical risk factors was also analyzed. The results of this study show that there are no pathologic features that carry a significant predictive value of the overall survival.

Adolescent↗
PubMed2005

Automated tissue analysis--a bioinformatics perspective.

OBJECTIVES: Recent progress in automated tissue analysis (tissomics) provides reproducible phenotypical characterization of histological specimens. We introduce informatics tools to cluster and correlate quantitative tissue profiles with gene expression data. The great potential of synergies between tissue analysis and bioinformatics and its perspectives in medical research and computational diagnostics are discussed. METHODS: Key enablers in microscopic imaging and machine vision are reviewed to perform a high-throughput tissue analysis. Methodologies are described and results are demonstrated that support a combined analysis of tissue with gene expression profiles whereby the consideration of individual responses is key. RESULTS: Comprehensive histomorphometric profiles, extracted using machine vision, provide information regarding the components and heterogeneity of a tissue in a reproducible format amenable to data mining and analysis. Tissue quantitative information can be placed in synergetic context with bioinformatics data, such as gene expression profiles, for a more comprehensive stratification of individual responses. From a bioinformatics point of view tissue data are co-variants that support the identification of candidate genes relevant in tissue injury or disease. CONCLUSIONS: Progress in automated analytics enables the generation of quantitative data about tissue previously limited to visual histopathology. Such reproducible data sets can be statistically correlated and clustered throughout the continuum of bioinformatics. The combined approach supports a system-wide view of biology and has a potential to accelerate developments for a personalized computational diagnosis.

Automation↗
PubMed1992

[Duplex ultrasound and color-coded Doppler ultrasound of visceral blood vessels in abdominal diseases].

Duplex Doppler sonography (DS) and color-flow Doppler sonography (FDS) are noninvasive diagnostic methods for the evaluation of a patient with suspected vascular disease of the abdomen. They represent a useful adjunct to realtime sonography in the identification of normal and variant visceral vascular anatomy. Aneurysms and pseudo-aneurysms of visceral arteries are readily differentiated from other cystic lesions. DS and FDS have a high sensitivity in the detection of portal vein thrombosis and stenosis. Both methods allow the observation and measurement of splanchnic hemodynamics in patients with chronic liver disease and portal hypertension. Hence, DS and FDS already play an important role in the pre- and postoperative assessment of patients undergoing liver or pancreas transplantation. The possibility that DS and FDS may enable discrimination between hypovascular and hypervascular tumors is under clinical investigation. FDS facilitates an excellent anatomic display of the abdominal vasculature and allows easy placement of the Doppler sample volume. Consequently, quantitative data acquired with DS are accomplished within short scanning times. However, the diagnostic impact of both modalities depends to a great extent on the experience of the investigator.

Abdominal Pain↗
PubMed2006

[Surveillance for influenza A virus infections in infants and young children in Beijing, China, 2001-2005].

OBJECTIVE: To characterize the prevalence and antigenic drift of influenza A viruses isolated during the period from 2001 to 2005 in infants and young children in Beijing. METHODS: MDCK cell culture, indirect immunofluorescence assay (IFA) and hemagglutination inhibition (HI) assay were used to isolate and identify type A influenza viruses (H1N1 and H3N2) from clinical samples collected from outpatients and inpatients who visited the Affiliated Children's Hospital because of acute respiratory infections from Oct. 2001 to Aug. 2005. The HA1 regions of hemagglutinin gene of H3N2 isolates were amplified by using RT-PCR followed by sequencing. RESULTS: Out of 7338 clinical samples collected during this surveillance period, 347 (4.7%) were positive for influenza A viruses, including 48 (13.8%) of H1N1, 273 (78.7%) of H3N2 and 26 (7.5%) of subtype-unidentified influenza A viruses. Although there was a prevalence season of influenza A from October each year to April of next year during the 2001-2004 period, it was worth noting that a consecutive influenza A activity was detected from Aug. 2004 to Aug. 2005, when some influenza A viruses were detected even in summer. The positive rate of H3N2 was 14.2% in August, 2005, which was equal to that of the peak season of 2003-2004. H3N2 were predominant in most of the influenza seasons during the surveillance period, and H1N1 was detected only in the influenza seasons of the 2001-2002 and 2004-2005 along with H3N2. The positive rates for both H3N2 and H1N1 were higher in specimens from outpatients than those from inpatients. A total of 46.6% (110/236) of the H3N2 were detected from children younger than 2 years of age, and 14.0% (33/236) were from children older than 5 years, whereas, more H1N1 was found in children older than 5 years (48.0%, 12/31) than in those younger than 2 years (6.5%, 2/31) during a period from Nov. 2003 to Aug. 2005. Sequence analysis of the HA1 regions of hemagglutinin of H3N2 isolated in a series of years revealed amino acid changes in the HA1 domain of H3N2 isolates in the antigenic sites (A-E) each year. CONCLUSION: H3N2 and H1N1 prevailed in each influenza season during the surveillance period in Beijing, and H3N2 strains were predominant. The data from all-year around surveillance of influenza in Beijing indicate that continuous surveillance throughout a year and use of both antigenic and molecular analysis will be more helpful for early identification of any antigenic variants as well as prevention and control of influenza by promoting development of vaccines.

Age Factors↗