Capillary-driven horseshoe vortex forming around a micro-pillar.

HYPOTHESIS: Horseshoe vortices are known to emerge around large-scale obstacles, such as bridge pillars, due to an inertia-driven adverse pressure gradient forming on the upstream-side of the obstacle. We contend that a similar flow structure can arise in thin-film Stokes flow around micro-obstacles, such as used in textured surfaces to improve wettability. This could be exploited to enhance mixing in microfluidic devices, typically limited to creeping-flow regimes. EXPERIMENTS: Numerical simulations based on the Navier-Stokes equations are carried out to elucidate the flow structure associated with the wetting dynamics of a liquid film spreading around a 50 µm diameter micro-pillar. The employed multiphase solver, which is based on the volume of fluid method, accurately reproduces the wetting dynamics observed in current and previous (Mu et al., Langmuir, 2019) experiments. FINDINGS: The flow structure within the liquid meniscus forming at the foot of the micro-pillar evinces a horseshoe vortex wrapping around the obstacle, notwithstanding that the Reynolds number in our system is extremely low. Here, the adverse pressure gradient driving flow reversal near the bounding wall is caused by capillarity instead of inertia. The horseshoe vortex is entangled with other vortical structures, leading to an intricate flow system with high-potential mixing capabilities.

Immune response to a 26-kDa protein, alkyl hydroperoxide reductase, in Helicobacter pylori-infected Mongolian gerbil model.

BACKGROUND: The host immune response is thought to play an important role in the outcome of Helicobacter pylori infection. The successful development of the H. pylori-infected Mongolian gerbil model that mimics human disease has enabled study of the antibody response against H. pylori antigens. MATERIALS AND METHODS: Serum samples from ulcer and carcinogenesis models of H. pylori-infected gerbils were used to screen for H. pylori antigens that cause a humoral immune response in the infected hosts. H. pylori alkyl hydroperoxide reductase (AhpC) is one such antigen on which we report here. The tsaA gene encoding AhpC was amplified by PCR from H. pylori ATCC 43504 strain, cloned into pMAL(TM)-c2 expression vector and expressed in Escherichia coli. Maltose-binding protein fusion protein (MBP-AhpC) was purified by a MBP affinity column. Using purified recombinant AhpC protein as an antigen, the antibody response and changes of antibody levels against AhpC in the gerbil models were studied by Western blotting and ELISA. RESULTS: Antibody against AhpC was negative in the early stages of infection, and became positive in the gerbils with the emergence of gastric diseases such as chronic active gastritis, gastric ulcer and gastric cancer. The antibody levels (ELISA) increased gradually over time and were higher in gerbils with gastric ulcer than that in gerbils without ulcers. CONCLUSIONS: Use of the gerbil model that mimics human H. pylori infection is likely to provide insights into the role of H. pylori-specific antigens possibly related to the subsequent development of gastric diseases.

Novel BCR-ABL transcript containing an intronic sequence insert in a patient with Philadelphia-positive acute lymphoblastic leukaemia.

In a patient with Philadelphia chromosome-positive acute lymphoblastic leukaemia (ALL), a novel variant of the chimaeric BCR-ABL mRNA transcript was detected by reverse transcription polymerase chain reaction (RT-PCR). Sequencing revealed the novel transcript to be a chimaeric mRNA produced by fusion of the BCR exon 14 (b3) to the ABL exon a2 with a 49-base pair (bp) insertion of an ABL intron 1b sequence between them. The insertion of the 49 bp introduced a stop codon. These data show that this variant of the chimaeric mRNA would not be translated into the p210 BCR-ABL protein. This could be one of the explanations as to why clinically the patient has responded well to therapy and continues to follow a mild clinical course.

Sandhoff disease in Cyprus: population screening by biochemical and DNA analysis indicates a high frequency of carriers in the Maronite community.

In the last 15 years, four patients with the infantile form of Sandhoff disease were diagnosed in four different families in Cyprus (population 703,000, birth rate 1.7%). Three of these cases came from the Christian Maronite community (less than 1% of the population) and one from the Greek community (84% of the population). This relatively large number of patients prompted us to initiate an epidemiological study in order to establish the frequency of the mutant allele in Cyprus. Carrier detection was initially based on the measurement of beta-hexosaminidase A and B in both leucocytes and serum. Using the enzyme test, 35 carriers were identified among 244 random Maronite samples and 15 among 28 Maronites with a family history of Sandhoff disease, but only one carrier was found out of 115 random samples from the Greek community. In parallel to the biochemical screening, DNA studies were undertaken in one of the three Maronite patients and in a Greek carrier related to the Greek patient. These studies resulted in the identification of two novel mutations, a deletion of A at nt76 and a G to C transversion at position 5 of the 5'-splice site of intron 8, which have been published. We subsequently screened the carriers detected in the biochemical study for these two mutations using PCR-based tests. Of 50 Maronite carriers examined, 42 were found to have the nt76 deletion. Eight Maronite samples, designated carriers from the biochemical results, were negative for both mutations. It is possible that these individuals were incorrectly classified as carriers since their enzyme values are equivocal, although the presence of another mutation has not been excluded. Two Greek Cypriot carriers and two obligate Lebanese carriers were negative for both mutations. We conclude that there is a high frequency of Sandhoff disease carriers in the Maronite community of Cyprus, approximately 1 in 7, and that a single mutation predominates in this population.

Novel deletional mutation of the MEN 1 gene in a kindred with multiple endocrine neoplasia type 1.

MEN1 gene mutation in a Japanese kindred with multiple endocrine neoplasia type 1 was examined. A heterozygous deletion involving 29 base pairs in exon 10 (1606del29) was identified in the proband, and the same deletion was found in the affected family members. Most previously reported germline MEN1 gene mutations are nucleotide substitutions and small insertions/deletions, and a large deletion is rare. The hairpin structure mediated by an incomplete palindromic sequence at deletion termini is the most likely mechanism to be associated with the deletion in the present family.

[The comparison of sensitivity between immunostaining and a simplified PCR-cold SSCP method in p53 genomic mutations].

The PCR-SSCP (single strand conformational polymorphism) method has been widely employed to screen mutations in a variety of genes because of its rapidity and simplicity in the operation. Using this method, we have examined mutations of some tumor-related genes including p53 and Ki-ras. In this study, we have evaluated the PCR-Cold (non radioactive) SSCP method for detection of p53 point mutations in comparison with immunohistological detection of p53 and PCR-direct sequencing. The results indicated that the PCR-Cold SSCP method had the same sensitivity with that of PCR-direct sequencing method, and had higher sensitivity than that of immunohistochemical method (IHC).

A novel non-pathogenetic polymorphism of the APC gene in a patient with familial adenomatous polyposis coli.

DISORDER: Familial adenomatous polyposis coli. ETHNICITY OF PATIENT: Japanese. GENE: APC. GENBANK ACCESSION NUMBER: M 74088. CHROMOSOMAL ASSIGNMENT: 5q21. TYPE OF DNA VARIANT: A germline missense mutation. A germline nonsense mutation. MUTATION: CGG (Arg, wild type) to TGG (Trp) substitution at codon 88 in exon 3 of the APC gene. CGA (Arg, wild type) to TGA (term.) at codon 213 in exon 5 of the APC gene. ALLELIC FREQUENCY: <0.014 (missense mutation, TGG at codon 88). METHOD OF MUTATION DETECTION: PCR-SSCP/direct sequencing.

Analysis of blood plasma proteins in patients with Alzheimer's disease by two-dimensional electrophoresis, sequence homology and immunodetection.

Blood plasma proteins of patients with Alzheimer's disease (AD; senile dementia) and non-AD-type dementia were resolved by two-dimensional electrophoresis and identified by migration position in the electrophoresis pattern, sequence homology, and immunodetection by using antibodies. For the control experiments, blood plasma proteins of a healthy young individual and non-dementia patients were examined in a manner similar to that of the plasma samples of AD patients. In the plasma sample of the healthy young individual, more than 350 spots of silver-stained proteins were observed and among these spots, 73 spots were identified. Blood plasma proteins of the AD and non-AD-type dementia patients were compared with those of the control and non-dementia patients. In the blood plasma samples of five AD patients, three patients had apolipoprotein E4, and another patient showed apolipoprotein L and complement factor H. For the AD-related proteins apolipoprotein E, tau-1, and presenilin 2, proteins were examined by immunostaining with antibodies, in both AD and non-AD patients. Among the three samples of non-AD-type dementia patients, one was distinguishable by amyloid A proteins, and the other by haptoglobin isoforms.

[Molecular diagnostic tests and chromosome analyses].

Molecular diagnostic tests and chromosomal analyses are often used to diagnose infectious, neoplastic and genetic diseases. However, there are only a few genetic laboratories in university hospitals in Japan because of the high cost and additional staff required for their management. In 1992, we started a genetic laboratory with one technologist in Shinshu University Hospital, and mainly performed polymerase chain reactions(PCR) for the diagnosis of several mycobacterial species, Hepatitis C virus and cytomegalovirus. Infectious diseases diagnosed by PCR have gradually increased over recent years. Chromosome analyses were available in 1996 and spectral karyotyping started from April 1999. Our genetic laboratory was staffed by 4 technologists and 3 faculty members in 1999, and they can provide informative tests with high quality. Molecular diagnostic tests were performed for 855 infectious diseases, 25 hematopoietic tumors and 8 solid tumors, while chromosome analyses were performed for 51 hereditary diseases and 29 hematopoietic tumors in 1998. Establishment of a genetic laboratory in a university hospital may not result in cost savings, but it produces a favorable influence on other laboratories. All staff can use molecular biology techniques to clarify limitations of routine tests and research.

Sensitive identification of mycobacterial species using PCR-RFLP on bronchial washings.

In 98 patients (24 with active pulmonary tuberculosis [TB] lesions, 28 with cured TB lesions, and 46 with nontuberculous opacities [control group] in chest CT scans), we examined whether washing the bronchus after brushing the lesion, then applying polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to the bronchial washings might be useful for diagnosing TB and nontuberculous mycobacteriosis (NTMosis). After biopsy and brushing with a bronchoscope, the bronchus connecting to the lesion was washed with 20 ml saline. The saline used for washing the brushes (5 ml; brushing sample), and 3 to 10 ml saline aspirated through the forceps channel (washing sample) were examined by PCR-RFLP, which proved able to identify Mycobacterium tuberculosis and seven species of nontuberculous mycobacteria (NTM). The values obtained for the sensitivity of the PCR-RFLP with respect to the brushing sample, the washing sample, and both samples mixed together were 70, 76, and 91%, respectively, when only patients who were culture-positive or radiologically improved after antituberculous therapy were considered as showing true infection. A mixture of brushing and washing samples provides useful material for PCR and culture, and the PCR-RFLP used here is a good method for the simultaneous identification of several species of mycobacterium (including M. tuberculosis).

Influence of oral Helicobacter pylori on the success of eradication therapy against gastric Helicobacter pylori.

BACKGROUND: The goal of this study was to see whether Helicobacter pylori (H. pylori) in the oral cavity might adversely affect the outcome of eradication therapy for gastric H. pylori. MATERIALS AND METHODS: Forty-seven patients (36 males, 11 females) with gastric H. pylori infection were enrolled in this study. Gastric H. pylori infection was confirmed by both immunohistological staining with anti-H. pylori antibody and bacterial culture of biopsy specimens. The therapeutic regimen consisted of 30 mg/day lansoprazole, 750 mg/day metronidazole, and 400 mg/day clarithromycin administered for 2 weeks. A fragment of the H. pylori urease gene was amplified by nested PCR for DNA extracted from saliva and dental plaque from the same patients. We examined the correlation between the gastric eradication success rate and the prevalence of H. pylori in the oral cavity as determined by PCR before and after the eradication therapy. RESULTS: The eradication success rate was significantly lower in the oral H. pylori-positive cases (12/23, 52.1%) than in the negative cases (22/24, 91.6%) at 4 weeks after the therapy (p =. 0028). Two years later, only 16 of the 23 (69.5%) oral H. pylori-positive cases were disease-free, as compared to 23 of the 24 (95.8%) oral H. pylori-negative cases (p =.018). CONCLUSIONS: H. pylori in the oral cavity affected the outcome of eradication therapy and was associated with a recurrence of gastric infection. We recommend that oral H. pylori should be examined by nested PCR and, if positive, should be considered a causal factor in refractory or recurrent cases.

[A report on staff development in advanced knowledge and technology of gene diagnosis for medical technologists by the Japanese Association of Medical Technologists: the view of medical technologists].

With advancement of the molecular biology, gene diagnosis is widely utilized in clinical application of medicine. For medical technologists, it is necessary to receive continued education to practice such advanced scientific trends. The Japanese Association of Medical Technologists established a working group for a staff development program of gene diagnosis and chromosome analysis in 1996, and has continued its activities in making inquiries about the present conditions, publishing a textbook, and providing seminars. The internal laboratory utilization of gene diagnosis was 8.7%(213 of 2437 hospitals). Based on the fact that about half of the hospitals use external laboratory, staff development for the internal utilization of gene diagnosis is an urgent issue. We have been providing seminars to meet the educational needs of our members. In addition to those activities, we have continued our efforts in providing a manual with clinically useful information, standardizing methods, establishing an information network, and conducting a controlled survey. The role of the working group is now shared by the local prefecture to further increase the numbers of those with expertise in gene diagnosis. We, medical technologists, need to have a global view of professional growth, and also to cooperate with academic societies related to gene diagnosis to establish a certification system.

[Clinical evaluation of PCR method for detection of cytomegalovirus DNA].

Polymerase chain reaction (PCR) to detect Cytomegalovirus (CMV)-DNA from the clinical specimens is useful to diagnose CMV infection. Eighty-one specimens of 31 patients including peripheral blood, bronchioalveolar lavage fluid, biopsy tissues, feces, urine, sputum and etc. and normal peripheral blood from 59 volunteers were used in this study. After DNA extraction each samples was amplified by the seminested PCR using primers recognizing sequences in the Immediate-early gene of CMV. This PCR method specifically detected more than 10 virus copies even in the presence of the genomic DNA. CMV-DNA was detected in only one of 59 normal peripheral bloods (1.7%). Six of 31 patients were clinically diagnosed as CMV infection by anti-CMV therapy. These 6 patients were positive in the peripheral blood by PCR for CMV, and 5 of them were positive in other samples. However, 3, 5 and 1 of 25 patients, who were clinically diagnosed as not having CMV infection, were also positive in peripheral blood, in the other samples and in both, respectively. The PCR method was able to examine any clinical samples. To examine both the peripheral blood and the samples from infected organs is helpful for the diagnosis of CMV infection.

[Genetic examination in clinical laboratory].

Genetic technology is finding active application today in the field of clinical laboratory medicine. Genetic examinations are divided into following three main classes: 1) examination for infectious disease according to the detection of the gene derived from bacteria or viruses, 2) examination for inherited disease according to molecular analysis of the genetic variation, 3) examination for oncogene according to molecular analysis of genetic abnormalities. At present, the main genetic examination in a large number of laboratories is for infectious disease because of its relatively simplified technique and high demand. The division of genetics is not a new independent section of clinical laboratory, but rather an ultramodern and powerful tool for existing divisions, such as biochemistry, serology, hematology, microbiology, and pathology. Genetic technology quickly provides results with high sensitivity and reliability, and plays a role at the core of the clinical laboratory. We should remember that the genetic technology is a great present given to clinical laboratories, however, it will eventually change into only one of the routine examinations according to the method of used. Examinations utilized in the clinical laboratory must be well established and standardized. Genetic examinations are no exception to that rule. These tests require a remarkably high precision since the results have an extraordinarily important meaning. There are more than 8,000 inherited diseases for instance. It is difficult to cover all examinations for those 8,000 in one laboratory. We need a network of laboratories that possess a genetic division, so that the examinations for as many inherited disease as possible can be comprehensively offered.

Preoperative chemotherapy for advanced esophageal cancer and relation with histological effect.

The results of surgical treatment for advanced esophageal cancer remain extremely poor. Irradiation and chemotherapy are not superior to surgery. Perioperative morbidity and the influence on long-term survival of a combination of surgery and preoperative chemotherapy were investigated in patients with advanced esophageal cancer. Forty-nine patients with advanced esophageal squamous cell carcinoma were subjected to preoperative chemotherapy of cisplatin-5-fluorouracil. Fifty-seven patients were chosen as a historical control group who had not undergone chemotherapy before surgery but had the same histological stages as the chemotherapy group. The response to chemotherapy was assessed by histological studies of surgical specimens. The survival rates noted no significant difference between preoperative chemotherapy plus surgery and a resection alone. However, subclassification according to the grading of chemotherapeutic effectiveness showed that, compared with control, preoperative chemotherapy was beneficial to high responders (P = 0.01), ineffective in low responders (P = 0.61), and detrimental to nonresponders (P = 0.03). Postoperative morbidity was significantly higher in the chemotherapy group than in the control group (P = 0.02). These findings suggest that preoperative chemotherapy is necessary only for high responders and we therefore need to reliably identify non-, low, and high responders before chemotherapy to improve the survival and quality of life of patients with advanced esophageal cancer.

Novel splice site mutation at IVS8 nt 5 of HEXB responsible for a Greek-Cypriot case of Sandhoff disease.

Sandhoff disease is caused by abnormalities in HEXB gene encoding the beta-subunit of beta-hexosaminidase. In this study, we analyzed the HEXB gene of a Sandhoff carrier in the Greek-Cypriot community. A G to C transversion was identified in one allele of her HEXB gene at position 5 of the 5'-splice site of intron 8 (IVS8 nt5). One of 13 cDNA clones derived from her lymphocyte HEXB mRNA lacked the last four nucleotides "GTTG" of exon 8, which created a premature termination codon at 11 codons downstream. In vivo transcription of the mutant HEXB gene fragment in CHO cells resulted in deletion of the "GTTG." The mutation has not been found in 40 DNA samples from anonymous donors, indicating that this is not a polymorphism in the Cypriot population. These results clearly indicate that the splice site mutation at IVS8 nt5 is responsible for this case of Sandhoff disease.