ABSTRACT
BACKGROUND: Surgical site infections (SSIs) are common complications after abdominal surgery. AIM: To compare which suture devices could reduce the incidence of incisional surgical site infections (SSIs) after gastrointestinal surgery using a systematic review and network meta-analysis. METHODS: The CENTRAL, PubMed, and ICHUSHI-Web databases were searched from January 1st, 2000, to December 31st, 2022, for randomized clinical trials (RCTs) comparing the incidence of incisional SSI after gastrointestinal surgery among patients treated with different surgical suture devices, including non-absorbable sutures, absorbable sutures, skin staplers, and tissue adhesives (last searched in August 23th, 2023). The risk of bias was assessed using the criteria of the Cochrane Handbook for Systematic Reviews of Interventions. To estimate the pooled odds ratios (ORs) for each comparison, a fixed-effect inverse-variance model based on the Mantel-Haenszel approach was employed. FINDINGS: A total of 18 RCTs with 5496 patients were included in this study. The overall SSIs in absorbable sutures were significantly lower than those in skin staplers (OR: 0.77; 95% confidence intervals (CI): 0.63-0.95) and non-absorbable sutures (OR: 0.62; 95% CI: 0.39-0.99), whereas SSIs in absorbable sutures were not significantly different from the SSIs in tissue adhesive. The highest P-score was 0.91 for absorbable sutures. A funnel plot for estimating the heterogeneity of the studies revealed that a publication bias would be minimal (Egger test, P = 0.271). CONCLUSION: This study showed that absorbable sutures reduced incisional SSIs in gastrointestinal surgical operations compared to any other suture devices.
Subject(s)
Digestive System Surgical Procedures , Surgical Wound Infection , Sutures , Surgical Wound Infection/epidemiology , Surgical Wound Infection/prevention & control , Surgical Wound Infection/etiology , Humans , Incidence , Sutures/adverse effects , Digestive System Surgical Procedures/adverse effects , Randomized Controlled Trials as Topic , Network Meta-AnalysisABSTRACT
The aim of this study was to conduct a systematic review and meta-analysis of the efficacy of fascial closure using antimicrobial-sutures specifically for the prevention of surgical site infections (SSIs) in gastrointestinal surgery, as part of the revision of the SSI prevention guidelines of the Japanese Society of Surgical Infectious Diseases (JSSI). We searched CENTRAL, PubMed and ICHUSHI-Web in May 2023, and included randomized controlled trials (RCTs) comparing antimicrobial-coated and non-coated sutures for fascial closure in gastrointestinal surgery (PROSPERO No. CRD42023430377). Three authors independently screened the RCTs. We assessed the risk of bias and the GRADE criteria for the extracted data. The primary outcome was incisional SSI and the secondary outcomes were abdominal wall dehiscence and the length of postoperative hospital stay. This study was supported partially by the JSSI. A total of 10 RCTs and 5396 patients were included. The use of antimicrobial-coated sutures significantly lowered the risk of incisional SSIs compared with non-coated suture (risk ratio: 0.79, 95% confidence intervals: 0.64-0.98). In subgroup analyses, antimicrobial-coated sutures reduced the risk of SSIs for open surgeries, and when monofilament sutures were used. Antimicrobial-coated sutures did not reduce the incidence of abdominal wall dehiscence and the length of hospital stay compared with non-coated sutures. The certainty of the evidence was rated as moderate according to the GRADE criteria, because of risk of bias. In conclusion, the use of antimicrobial-coated sutures for fascial closure in gastrointestinal surgery is associated with a significantly lower risk of SSI than non-coated sutures.
Subject(s)
Frail Elderly , Independent Living , Liver Neoplasms/surgery , Aged , Hepatectomy , Humans , Liver Neoplasms/rehabilitation , Nomograms , Prospective StudiesABSTRACT
Mutations in the connexin26 gene (GJB2) are the most common genetic cause of congenital bilateral non-syndromic sensorineural hearing loss. Transgenic mice were established carrying human Cx26 with the R75W mutation that was identified in a deaf family with autosomal dominant negative inheritance [Kudo T et al. (2003) Hum Mol Genet 12:995-1004]. A dominant-negative Gjb2 R75W transgenic mouse model shows incomplete development of the cochlear supporting cells, resulting in profound deafness from birth [Inoshita A et al. (2008) Neuroscience 156:1039-1047]. The Cx26 defect in the Gjb2 R75W transgenic mouse is restricted to the supporting cells; it is unclear why the auditory response is severely disturbed in spite of the presence of outer hair cells (OHCs). The present study was designed to evaluate developmental changes in the in vivo and in vitro function of the OHC, and the fine structure of the OHC and adjacent supporting cells in the R75W transgenic mouse. No detectable distortion product otoacoustic emissions were observed at any frequencies in R75W transgenic mice throughout development. A characteristic phenotype observed in these mice was the absence of the tunnel of Corti, Nuel's space, and spaces surrounding the OHC; the OHC were compressed and squeezed by the surrounding supporting cells. On the other hand, the OHC developed normally. Structural features of the lateral wall, such as the membrane-bound subsurface cisterna beneath the plasma membrane, were intact. Prestin, the voltage-dependent motor protein, was observed by immunohistochemistry in the OHC basolateral membranes of both transgenic and non-transgenic mice. No significant differences in electromotility of isolated OHCs during development was observed between transgenic and control mice. The present study indicates that normal development of the supporting cells is indispensable for proper cellular function of the OHC.
Subject(s)
Connexins/genetics , Gap Junctions/metabolism , Hair Cells, Auditory, Outer/metabolism , Hearing/genetics , Labyrinth Supporting Cells/metabolism , Organ of Corti/metabolism , Acoustic Stimulation , Animals , Cell Communication/genetics , Connexin 26 , Electric Capacitance , Gap Junctions/ultrastructure , Genetic Predisposition to Disease/genetics , Hair Cells, Auditory, Outer/pathology , Hearing Loss, Sensorineural/genetics , Hearing Loss, Sensorineural/metabolism , Hearing Loss, Sensorineural/physiopathology , Labyrinth Supporting Cells/pathology , Mechanotransduction, Cellular/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Molecular Motor Proteins/metabolism , Mutation/genetics , Nonlinear Dynamics , Organ of Corti/pathology , Organ of Corti/physiopathology , SoundABSTRACT
OBJECTIVE: This study evaluated the influence of Carisolv (Medi Team) for resin adhesion to sound human primary and young permanent dentin. METHODS: The buccal surfaces of 28 primary molars and 64 premolars were used. Two adhesive systems and resin composites were used; SE: Clearfil SE (Kuraray) and Clearfil APX (Kuraray), and SB: Single Bond (3M) and Z250 (3M). Six groups were prepared. Groups 1-2 were primary dentin and Groups 3-6 were permanent dentin. Groups 1 and 3: SE was used. Groups 2 and 4: treated with Carisolv and then primed, SE was used. Group 5: SB was used. Group 6: treated with Carisolv and then etched, SB was used. The microstructural effects of primer or etchant, and Carisolv plus primer or etchant applied to dentin were evaluated by SEM. In addition, the microstructure of the resin-dentin interfaces of each group was studied using SEM. Shear bond strengths (SBS) were tested, and the failed surfaces were observed using SEM. Data was statistically analyzed using ANOVA with subsequent application of Fisher's PLSD at p<0.05. RESULTS: The mean SBS (unit: MPa) of Groups 1-6 were: 27.8, 19.2, 21.3, 21.7, 6.7 and 7.6. The SBS of Group 2 was significantly lower than that of Group 1. There was no significant difference of the SBS among Groups 1 and 4, 2, 3 and 4, and 5 and 6. In SE groups, the hybrid layer for primary dentin was thicker than that for permanent dentin. CONCLUSIONS: Carisolv treatment before priming significantly decreased the SBS to primary dentin in SE groups, but did not influence the SBS to permanent dentin in both SE and SB groups.
Subject(s)
Composite Resins/chemistry , Dental Bonding , Dental Cavity Preparation/methods , Dentin-Bonding Agents/chemistry , Dentin/ultrastructure , Glutamic Acid/therapeutic use , Leucine/therapeutic use , Lysine/therapeutic use , Tooth, Deciduous/ultrastructure , Acid Etching, Dental , Bicuspid , Bisphenol A-Glycidyl Methacrylate/chemistry , Humans , Materials Testing , Methacrylates/chemistry , Microscopy, Electron, Scanning , Molar , Resin Cements/chemistry , Stress, Mechanical , Surface PropertiesABSTRACT
Mutation analysis of the PDS gene and the EYA1 gene, which are reported to be responsible for hearing loss associated with ear anomalies, was performed in 24 deaf patients with various middle and inner ear anomalies. The present study was done to clarify the spectrum of middle and inner ear malformations covered by these two genes. PDS mutations were found only in patients with enlarged vestibular aqueducts and EYA1 mutations were detected only in patients with ear pits and cervical fistulae, indicating that these two genes are associated with particular forms of middle and inner ear malformation. The genetic approach provides a strong tool for the diagnosis of hearing loss associated with ear anomalies.
Subject(s)
Carrier Proteins/genetics , Congenital Abnormalities/genetics , Deafness/genetics , Ear/abnormalities , Membrane Transport Proteins , Mutation , Trans-Activators/genetics , Adolescent , Adult , Child , DNA Mutational Analysis , Deafness/etiology , Female , Genes, Dominant , Genes, Recessive , Humans , Intracellular Signaling Peptides and Proteins , Male , Middle Aged , Nuclear Proteins , Protein Tyrosine Phosphatases , Sulfate TransportersABSTRACT
Sixteen Japanese nonsyndromic autosomal dominant sensorineural hearing loss (ADSNHL) families were investigated clinically as well as genetically. Most families showed postlingual hearing loss. Although the severity of their hearing loss varied, most patients showed mild-moderate sensorineural hearing loss of a progressive nature. Mutation analysis was performed for the MYO7A, KCNQ4, and GJB3 genes, which are known to be responsible for autosomal dominant sensorineural hearing loss. The present study reports that a mutation in KCNQ4, a member of a large family of potassium channel genes, was responsible for ADSNHL in one Japanese family.
Subject(s)
Genes, Dominant/genetics , Hearing Loss, Sensorineural/genetics , Hearing Loss, Sensorineural/physiopathology , Potassium Channels, Voltage-Gated , Potassium Channels/genetics , Adolescent , Adult , Aged , Audiometry , Base Sequence , Child , Child, Preschool , Connexins/genetics , DNA Mutational Analysis , Dyneins , Exons/genetics , Female , Genotype , Humans , Japan , KCNQ Potassium Channels , Male , Middle Aged , Mutation , Myosin VIIa , Myosins/genetics , Pedigree , Phenotype , Polymorphism, Genetic/geneticsABSTRACT
The localization of three glutathione S-transferase (GST) isoforms in the rat cochlea was examined using specific antibodies against each isoform. GST immunoreactivities were found in particular parts of the cochlea, including the intermediate cells and the basal cells of the stria vascularis and various types of fibrocytes in the spiral ligament. The different cell types showed varying combinations of GST isoforms. The GST immunopositive cells identified in the present study may play a central role in the metabolism and inactivation of endogenous and exogenous ototoxic compounds. The specific arrangements also indicated a possible contribution to the detoxification process in the form of a blood-labyrinth barrier.
Subject(s)
Cochlea/enzymology , Cochlea/ultrastructure , Glutathione Transferase/metabolism , Protein Isoforms/metabolism , Animals , Antibody Specificity/immunology , Blood-Brain Barrier/physiology , Immunohistochemistry , Microscopy, Confocal , Microscopy, Electron , Neurotoxins/pharmacology , Rats , Rats, WistarABSTRACT
We report an extremely rare case of chondrosarcoma arising in the left parotid gland in a 45-year-old man who complained of painless swelling of the postauricular region. Computed tomography revealed a well-circumscribed tumor in the parotid area with a rim of scattered calcification. Under the diagnosis of benign parotid tumor, the tumor mass was removed with adequate margin. Histologic features were consistent with a low-grade chondrosarcoma showing lobular growth but clearly separated from adjacent glandular tissue of the parotid gland. Entire examination of the tumor disclosed no component of pleomorphic adenoma. There has been no evidence of recurrence for 2 months after the operation. The current case indicates that the parotid gland could be the site of occurrence of de novo primary chondrosarcoma.
Subject(s)
Chondrosarcoma/pathology , Parotid Neoplasms/pathology , Chondrosarcoma/diagnostic imaging , Chondrosarcoma/surgery , Diagnosis, Differential , Humans , Male , Middle Aged , Parotid Gland/pathology , Parotid Neoplasms/diagnostic imaging , Parotid Neoplasms/surgery , Tomography, X-Ray ComputedABSTRACT
Recent genetic studies have shown that hereditary susceptibility to aminoglycoside antibiotics is caused by the 1555 A-->G mitochondrial mutation. We found the 1555 mutation in 4 out of 68 postlingual deaf patients who were candidates for cochlear implantation. All 4 patients developed bilateral profound hearing loss following administration of aminoglycosides. The pedigree of the family shows exclusively maternal transmission of hearing impairment in each case. On comparison with neuro-otological findings from aminoglycoside-induced deaf patients without the 1555 mutation, four distinct characteristics were noted: (1) a progressive nature of hearing loss; (2) better residual pure-tone thresholds; (3) lower thresholds for electrical promontory stimulation, and (4) well-preserved vestibular function. Although other factors such as differing dosages and/or administration routes may also be involved, profound hearing loss associated with the 1555 mutation may be due to a different pathogenic mechanism, i.e., strial dysfunction rather than a direct insult to the hair cells.
Subject(s)
Anti-Bacterial Agents/adverse effects , DNA, Mitochondrial/genetics , Deafness/chemically induced , Deafness/genetics , Mutation , Aged , Aminoglycosides , Audiometry, Pure-Tone , Female , Humans , Male , Middle Aged , PedigreeABSTRACT
We have previously demonstrated the presence of gap junctions between melanocytes in the human vestibular organ and have speculated that melanocytes function in maintaining the homeostasis of the microenvironment of the inner ear. The purpose of the present study was to characterize the expression and ultrastructural localization of connexin (Cx) protein in melanocytes of the human vestibular organs. Surgical material was obtained from patients operated on for vestibular schwannoma and was processed for light microscopy, confocal laser scanning microscopy, conventional TEM, and immuno TEM. The specimens were labeled with anti-Cx26, Cx32, and Cx43 antibodies and examined by light microscopy. Specimens were also labeled with anti-Cx26 antibody and examined by laser microscopy and immuno-TEM methods. The specimens examined in this study were mainly dark cell areas from the human vestibular organ, whose epithelial and subepithelial layers are rich in melanocytes. Light-microscopic immunohistochemical studies showed positive labeling for Cx26 protein between subepithelial melanocytes, and Cx32 was also detected. Use of anti-Cx26 antibody and confocal laser scanning microscopy revealed high levels of Cx26 around the subepithelial melanocytes. Post-embedding immuno-gold transmission electron microscopy showed significant aggregation of gold particles (33.97 +/- 8.01% of total gold particles) around the gap junctions of the subepithelial melanocytes. The results of this study indicated that melanocytes are connected through gap junctions that mainly contain Cx26. This suggested that the melanocytes in the human vestibular organ may play a role in transporting material between the endolymph and perilymph.
Subject(s)
Connexins/analysis , Gap Junctions/chemistry , Melanocytes/chemistry , Vestibule, Labyrinth/chemistry , Adult , Aged , Connexin 26 , Connexin 43/analysis , Female , Gap Junctions/ultrastructure , Humans , Immunohistochemistry , Male , Melanocytes/ultrastructure , Microscopy, Electron , Middle Aged , Vestibule, Labyrinth/ultrastructure , Gap Junction beta-1 ProteinABSTRACT
GABA is synthesized by glutamate decarboxylase (GAD), which has two forms, GAD65 and GAD67. To elucidate the molecular mechanisms of mouse GAD65 (mGAD65) gene expression, we isolated and characterized the mGAD65 gene. The mGAD65 gene was found to be divided into 16 exons and spread over 75 kb. The sequence of the first exon and the 5'-flanking region indicated the presence of potential neuron-specific cis-regulatory elements. We used transgenic mice to examine the expression pattern conferred by a 9.2-kb promoter-proximal DNA fragment of the mGAD65 gene fused to the bacterial lacZ reporter gene. Transgenic mice showed high beta-galactosidase activity specifically in brain and testis. They also showed characteristic patterns of transgene expression in olfactory bulb, cerebellar cortex, and spinal cord, a similar expression pattern to that of endogenous mGAD65. However, no transgene expression was observed in the ventral thalamus or hypothalamus, in which high mGAD65 gene expression levels have been observed. These results suggest that the 9.2-kb DNA fragment of the mGAD65 gene is associated with its tissue-specific expression and its targeted expression in GABAergic neurons of specific brain regions but that additional regulatory elements are necessary to obtain fully correct expression.
Subject(s)
Glutamate Decarboxylase/genetics , Isoenzymes/genetics , Neurons/metabolism , Promoter Regions, Genetic/genetics , gamma-Aminobutyric Acid/metabolism , Amino Acid Sequence , Animals , Base Sequence , Brain/cytology , Brain/metabolism , Cloning, Molecular , Exons , Gene Expression , Genes, Regulator , Genes, Reporter , Introns , Mice , Mice, Transgenic , Molecular Sequence Data , Neurons/cytology , Organ Specificity/genetics , RNA, Messenger , Sequence Analysis, DNA , Transgenes , beta-Galactosidase/geneticsABSTRACT
A 68-year-old man who had Borrmann type 4 gastric cancer with multiple liver metastases was admitted to our hospital on October 20, 1998. He was considered nonresectable and placed on neoadjuvant chemotherapy consisting of low-dose CDDP and 5-FU. After 9 weeks of administration, the liver metastases had disappeared on abdominal computed tomography, but the primary lesion had progressed. On May 12, 1999, a total gastrectomy with a partial resection of the transverse colon and resectional biopsy of a white nodule of the liver were performed. This was a non-curative operation because of the peritoneal dissemination. A histopathological examination of the liver nodule revealed that the cancer cells had disappeared. The patient had an uneventful postoperative course and 4 weeks of chemotherapy were added. He remains alive with no symptoms or re-growth of the liver metastatic tumor 4 months after the surgery.
Subject(s)
Adenocarcinoma/drug therapy , Adenocarcinoma/secondary , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Liver Neoplasms/secondary , Stomach Neoplasms/drug therapy , Stomach Neoplasms/pathology , Adenocarcinoma/surgery , Aged , Cisplatin/administration & dosage , Combined Modality Therapy , Drug Administration Schedule , Fluorouracil/administration & dosage , Gastrectomy , Humans , Infusions, Intravenous , Liver Neoplasms/drug therapy , Male , Neoadjuvant Therapy , Stomach Neoplasms/surgerySubject(s)
DNA, Mitochondrial/genetics , Hearing Loss, Sensorineural/genetics , Mutation , Female , Humans , Male , Pedigree , Point MutationABSTRACT
We report a 48-year-old-man with gastric carcinoma presenting with an unusual extraluminal growth. The patient underwent a barium meal examination and gastrofiberscopy because of progressive anemia over 6 months. These examinations revealed a Borrmann type 3 advanced gastric carcinoma of the greater curvature of the antrum. Biopsies showed moderately differentiated tubular adenocarcinoma. The intraoperative findings showed gastric carcinoma associated with extensive extraluminal invasion into the adjacent organs, i.e., the transverse colon and mesocolon. A palliative distal gastrectomy with a partial resection of the transverse colon was performed because of peritoneal dissemination found in the mesocolon and rectovesical pouch. A histological examination of the specimen confirmed adenocarcinoma which had massively infiltrated the transverse colon and mesocolon. His postoperative course was uneventful. However, he died of peritonitis carcinomatosa 9 months later.
Subject(s)
Adenocarcinoma/diagnosis , Colonic Neoplasms/diagnosis , Neoplasms, Multiple Primary/diagnosis , Stomach Neoplasms/diagnosis , Adenocarcinoma/surgery , Biopsy, Needle , Colectomy/methods , Colonic Neoplasms/surgery , Fatal Outcome , Follow-Up Studies , Gastrectomy/methods , Gastroscopy , Humans , Male , Middle Aged , Neoplasm Invasiveness , Neoplasms, Multiple Primary/surgery , Palliative Care , Stomach Neoplasms/surgery , Tomography, X-Ray ComputedABSTRACT
The 200kb linear plasmid pSLA2-L was suggested to be involved in the production of two macrolide antibiotics, lankamycin (Lm) and lankacidin (Lc), in Streptomyces rochei 7434AN4. Hybridization experiments with the polyketide synthase (PKS) genes for erythromycin and actinorhodin identified two eryAI-homologous regions and an actI-homologous region on pSLA2-L. The nucleotide sequence of a 3.6kb SacI fragment carrying one of the eryAI-homologs revealed that it codes for part of a large protein with four domains for ketoreductase, acyl carrier protein, ketosynthase, and acyltransferase. Gene disruption confirmed that the two eryAI-homologs are parts of a large type-I PKS gene cluster for Lm. A 4.8kb DNA carrying the actI-homologous region contains four open reading frames (ORF1-ORF4) as well as an additional ORF, i.e. ORF5, which might code for a thioesterase. Deletion of the ORF2-ORF4 region showed that it is not involved in the synthesis of Lm or Lc. Thus, it was confirmed that pSLA2-L contains two PKS gene clusters for Lm and an unknown type-II polyketide.
Subject(s)
Macrolides , Multienzyme Complexes/genetics , Multigene Family/genetics , Plasmids/genetics , Streptomyces/genetics , Amino Acid Sequence , Anthraquinones/metabolism , Anti-Bacterial Agents/biosynthesis , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Erythromycin/analogs & derivatives , Erythromycin/biosynthesis , Genes, Bacterial/genetics , Molecular Sequence Data , Mutagenesis , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Streptomyces/enzymology , Streptomyces/metabolismABSTRACT
The frequency of three mitochondrial point mutations, 1555A-->G, 3243A-->G, and 7445A-->G, known to be associated with hearing impairment, was examined using restriction fragment length polymorphism (RFLP) analysis in two Japanese groups: (1) 319 unrelated SNHL outpatients (including 21 with aminoglycoside antibiotic injection history), and (2) 140 cochlear implantation patients (including 22 with aminoglycoside induced hearing loss). Approximately 3% of the outpatients and 10% of the cochlear implantation patients had the 1555A-->G mutation. The frequency was higher in the patients with a history of aminoglycoside injection (outpatient group 33%, cochlear implantation group 59%). One outpatient (0.314%) had the 3243A-->G mutation, but no outpatients had the 7445A-->G mutation and neither were found in the cochlear implantation group. The significance of the 1555A-->G mutation, the most prevalent mitochondrial mutation found in this study of a hearing impaired population in Japan, among subjects with specific backgrounds, such as aminoglycoside induced hearing loss, is evident.
Subject(s)
DNA, Mitochondrial/genetics , Hearing Loss, Sensorineural/genetics , Point Mutation , Polymorphism, Restriction Fragment Length , Aminoglycosides , Anti-Bacterial Agents/adverse effects , Cochlear Implantation , DNA, Mitochondrial/blood , Hearing Loss, Sensorineural/chemically induced , Hearing Loss, Sensorineural/surgery , Humans , JapanABSTRACT
The gene responsible for DNFB1 and DFNA3, connexin 26 (GJB2), was recently identified and more than 20 disease causing mutations have been reported so far. This paper presents mutation analysis for GJB2 in Japanese non-syndromic hearing loss patients compatible with recessive inheritance. It was confirmed that GJB2 mutations are an important cause of hearing loss in this population, with three mutations, 235delC, Y136X, and R143W, especially frequent. Of these three mutations, 235delC was most prevalent at 73%. Surprisingly, the 35delG mutation, which is the most common GJB2 mutation in white subjects, was not found in the present study. Our data indicated that specific combinations of GJB2 mutation exist in different populations.
Subject(s)
Connexins/genetics , Hearing Loss, Sensorineural/genetics , Mutation , Amino Acid Substitution , Connexin 26 , Female , Frameshift Mutation , Hearing Loss, Sensorineural/epidemiology , Humans , Japan/epidemiology , Male , Mutation, Missense , Pedigree , Point Mutation , Polymorphism, Genetic , Prevalence , Sequence DeletionABSTRACT
The 1555A-->G point mutation is associated with a susceptibility to aminoglycoside antibiotics, and is of particular interest, as it may cause hearing loss even without aminoglycoside exposure. There may be a considerably large high-risk population in Japan, and to avoid possible side effects in this group, a rapid mass screening system and careful counseling are recommended. We are currently using the mutant allele specific amplification (MASA) method to detect the 1555A-->G mitochondrial mutation and we distribute a warning card to subjects found to bear this mutation.
Subject(s)
DNA, Mitochondrial/genetics , Genetic Counseling , Genetic Testing/methods , Point Mutation , Aminoglycosides , Anti-Bacterial Agents/adverse effects , Base Sequence , Hearing Loss, Sensorineural/chemically induced , Hearing Loss, Sensorineural/genetics , Humans , Japan , Polymorphism, Restriction Fragment Length , Risk FactorsABSTRACT
A filamentous soil bacterium, Streptomyces griseus 2247, carries a 7. 8-Mb linear chromosome. We previously showed by macrorestriction analysis that mutagenic treatments easily caused deletions at both ends of its linear chromosome and changed the chromosome to a circular form. In this study, we confirmed chromosomal circularization by cloning and sequencing the junction fragments from two deletion mutants, 404-23 and N2. The junction sequences were compared with the corresponding right and left deletion end sequences in the parent strain, 2247. No homology and a 6-bp microhomology were found between the two deletion ends of the 404-23 and N2 mutants, respectively, which indicate that the chromosomal circularization was caused by illegitimate recombination without concomitant amplification. The circularized chromosomes were stably maintained in both mutants. Therefore, the chromosomal circularization might have occurred to prevent lethal deletions, which otherwise would progress into the indispensable central regions of the chromosome.