Mitochondrial ribosomal RNA mutation associated with both antibiotic-induced and non-syndromic deafness

Maternally transmitted non-syndromic deafness was described recently both in pedigrees with susceptibility to aminoglycoside ototoxicity and in a large Arab-Israeli pedigree. Because of the known action of aminoglycosides on bacterial ribosomes, we analysed the sequence of the mitochondrial rRNA genes of three unrelated patients with familial aminoglycoside-induced deafness. We also sequenced the complete mitochondrial genome of the Arab-Israeli pedigree. All four families shared a nucleotide 1555 A to G substitution in the 12S rRNA gene, a site implicated in aminoglycoside activity. Our study offers the first description of a mitochondrial rRNA mutation leading to disease, the first cases of non-syndromic deafness caused by a mitochondrial DNA mutation and the first molecular genetic study of antibiotic-induced ototoxicity.

The complete genome sequence of Lactobacillus bulgaricus reveals extensive and ongoing reductive evolution

Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) is a representative of the group of lactic acid-producing bacteria, mainly known for its worldwide application in yogurt production. The genome sequence of this bacterium has been determined and shows the signs of ongoing specialization, with a substantial number of pseudogenes and incomplete metabolic pathways and relatively few regulatory functions. Several unique features of the L. bulgaricus genome support the hypothesis that the genome is in a phase of rapid evolution. (i) Exceptionally high numbers of rRNA and tRNA genes with regard to genome size may indicate that the L. bulgaricus genome has known a recent phase of important size reduction, in agreement with the observed high frequency of gene inactivation and elimination; (ii) a much higher GC content at codon position 3 than expected on the basis of the overall GC content suggests that the composition of the genome is evolving toward a higher GC content; and (iii) the presence of a 47.5-kbp inverted repeat in the replication termination region, an extremely rare feature in bacterial genomes, may be interpreted as a transient stage in genome evolution. The results indicate the adaptation of L. bulgaricus from a plant-associated habitat to the stable protein and lactose-rich milk environment through the loss of superfluous functions and protocooperation with Streptococcus thermophilus.

Mitochondrial ribosomal RNA gene mutation in a patient with sporadic aminoglycoside ototoxicity

PURPOSE

Aminoglycoside-induced deafness has been described in a number of Chinese pedigrees. In nearly all of these families, affected individuals were related through the maternal side. Because mitochondrial DNA is transmitted exclusively through mothers, it had been speculated that a mutation in the mitochondrial DNA might predispose these maternally related family members to aminoglycoside ototoxicity. Recently, we analyzed three such families with multiple cases of ototoxic deafness and identified a pathogenic mutation in the mitochondrial 12S ribosomal RNA gene at nucleotide position 1555. The purpose of the current study is to analyze individuals with no family history of deafness, who had severe hearing loss after aminoglycoside exposure, for presence or absence of this particular mitochondrial DNA mutation.

MATERIALS AND METHODS

Blood was obtained from 36 Chinese individuals who became deaf after aminoglycoside exposure and had no family history of deafness. The DNA of these individuals was extracted, amplified by the polymerase chain reaction, and analyzed for the mitochondrial ribosomal RNA gene mutation by allele-specific oligonucleotide hybridization and Southern blot analysis.

RESULTS

In one of these 36 sporadic cases, we identified the nucleotide 1555 A-->G mutation in the mitochondrial genome.

CONCLUSION

This finding implies that a small proportion of individuals at risk for aminoglycoside ototoxicity harbor the specific mitochondrial DNA mutation identified in the familial cases. In these individuals, a genetic susceptibility to the ototoxic effects of aminoglycosides can be diagnosed, and deafness can be prevented in maternal relatives by avoiding the use of these antibiotics.

Structural and content diversity of mitochondrial genome in beet: a comparative genomic analysis

Despite their monophyletic origin, mitochondrial (mt) genomes of plants and animals have developed contrasted evolutionary paths over time. Animal mt genomes are generally small, compact, and exhibit high mutation rates, whereas plant mt genomes exhibit low mutation rates, little compactness, larger sizes, and highly rearranged structures. We present the (nearly) whole sequences of five new mt genomes in the Beta genus: four from Beta vulgaris and one from B. macrocarpa, a sister species belonging to the same Beta section. We pooled our results with two previously sequenced genomes of B. vulgaris and studied genome diversity at the species level with an emphasis on cytoplasmic male-sterilizing (CMS) genomes. We showed that, contrary to what was previously assumed, all three CMS genomes belong to a single sterile lineage. In addition, the CMSs seem to have undergone an acceleration of the rates of substitution and rearrangement. This study suggests that male sterility emergence might have been favored by faster rates of evolution, unless CMS itself caused faster evolution.

New Evidence of Premature Oxidative DNA Damage: Mitochondrial DNA Deletion in Gingival Tissue of Patients With Periodontitis

BACKGROUND

Overproduction of reactive oxygen species (ROS) causes increased oxidative stress in gingival tissue. It has been generally accepted that increased oxidative stress might contribute to additional damage of lipids, proteins, and DNA molecules. The mitochondrial DNA (mtDNA) mutation is a superb biomarker of oxidative damage. The aim of the present study was to investigate the mtDNA deletions in the gingival tissue of patients with periodontitis and to explain the correlations between mtDNA deletion in gingival tissue and clinical parameters of periodontitis and age.

METHODS

Gingival tissue and blood samples were collected from 30 patients with chronic periodontitis (CP group) and 30 healthy control subjects (H group). To determine the clinical condition of each subject, the plaque index, gingival index, clinical attachment level, and probing depth were measured. Using the polymerase chain reaction (PCR) method, we examined the 7.4- and 5-kbp mtDNA deletions in tissue and blood samples. Three different pairs of PCR primers were used in this study.

RESULTS

In this study, we did not detect any deletions in blood DNA samples in either the CP or H group. Also, the 7.4-kbp mtDNA deletion was not detected in gingival tissues of subjects. However, the 5-kbp mtDNA deletion was detected in 24 of the 30 subjects (80%) in the CP group and was not detected in the H group (0%). Significant correlations were found between the occurrence of the 5-kbp mtDNA deletion and all clinical parameters (P <0.01). A similar correlation was found between the occurrence of the 5-kbp mtDNA deletion and age (P <0.05).

CONCLUSIONS

The overproduction of ROS by activated polymorphonuclear leukocytes in chronic inflammation may lead to premature oxidative damage of the mtDNA. In this study, the occurrence of the 5-kbp mtDNA deletion in 24 periodontitis subjects may be evidence of premature oxidative DNA damage.

Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

INTRODUCTION

Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN).

METHODS

The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period.

RESULTS

In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05).

CONCLUSIONS

This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

Primary hypogonadism, partial alopecia, and Mullerian hypoplasia: report of a third family and review

Two sisters presented with partial alopecia, primary hypergonadotropic hypogonadism and Mullerian hypoplasia associated with mild mental retardation, microcephaly, flat occiput, sparse eyebrows, absence of breast tissue, absent ovaries, mild-moderate dorsal kyphosis, thin upper lip and unilateral sensorioneural deafness in one of them. They were the product of a Turkish consanguineous marriage. The clinical course for our patients is similar to two families reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622] and Megarbane et al. [Megarbane et al. (2003) Am J Med Genet Part A 119A:214-217]. This report supports the literature by proposing an autosomal recessive syndrome which was firstly reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622]. This condition may be due to a founder mutation.

Invasive lobular carcinoma of the male breast: a case report

A case of lobular carcinoma in a male breast is described. Because the structure of the male breast does not have lobules and acini, lobular carcinoma cases are seen infrequently. The pathological diagnosis was invasive lobular carcinoma of the breast. The karyotype of the patient revealed a 46 XY/46 XY, dmin (double minutes) chromosomal structure. Although 28% of the examined metaphases showed 46 XY, 1-5 dmin, the others were normal. We reviewed the English literature and found 20 reported cases of lobular carcinoma of the male breast. Our case represents lobular carcinoma in a proven genotypic male patient showing no exogenous or endogenous estrogens.

Sister chromatid exchange analysis and chromosoma aberration studies in interventional cardiology laboratory workers: one war follow up study

Invasive cardiology laboratory workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation has a damaging effect on chromosomes. In present study. we investigated the frequency of sister chromatid exchange (SCE) and chromosomal aberrations in 11 invasive cardiology laboratory workers and 11 healthy controls. After a vacation period, we took blood samples for chromosome analysis in months 0, 4, 8 and 12 (last two month period was the nonradiation time). The SCE frequencies did not change significantly after exposure to ionizing radiation in any worker. Our study has revealed that non-specific structural chromosome aberrations such as gaps, isogaps, acentric chromosomes, chromatids and chromosome breakage could be in the 4th and 8th months after ionizing radiation exposure in the metaphase plaques. All abnormal chromosomal effects had disappeared by the end of the two month non-exposure period in each worker. In conclusion, the results suggest that SCE frequencies are not significantly affected in invasive cardiology laboratory workers who are exposed occupationally to ionizing radiation, although some degree of reversible chromosomal aberrations did appear.

Genotoxic effect of albendazole in pediatric patients with hepatic hydatid disease

OBJECTIVE

Hydatid disease occurs throughout the world and is treated with both surgery and medical administration of albendazole. Some adverse effects of albendazole are known. However, its genotoxic effect on humans has not been reported yet. In this study, we aimed to investigate the genotoxic effect of albendazole on human lymphocytes in vivo.

METHODS

The study involved 14 children (eight males and six females) who had undergone operations for hepatic hydatid disease. The ages of the patients ranged from 6 to 13 years. Genotoxicity of albendazole was evaluated as the frequency of sister chromatid exchange (SCE) and micronucleated cells in the patient's lymphocytes. Prior to and after albendazole treatment, blood samples were obtained from these patients for SCE and micronucleus (MN) studies. SCE and MN frequencies of the patients were measured separately before and after albendazole treatment.

RESULTS

All patient SCE values increased significantly after albendazole administration (p<0.001). Similarly, MN frequencies in all the patients increased significantly following albendazole treatment (p<0.001).

CONCLUSION

This study revealed that both SCE and MN frequencies are higher after albendazole treatment. The results suggest that albendazole may be genotoxic to human lymphocytes in vivo.

What is the neutrophil/lymphocyte ratio in sarcoidosis?

AIM

Information regarding the Neutrophil/Lymphocyte ratio (NLR) in sarcoidosis and the data from studies recommending its use as an indicator of inflammation and in the differential diagnosis and prognosis, are limited. With this study, it was aimed to obtain data regarding the NLR level in the patients at the time of presentation to the hospital and to determine the characteristics of patients in whom the NLR value was > 2.

RESULTS

During the study period, of the 3434 patients with the sub-diagnosis of D86, 1300 cases whose complete blood count values had been recorded at the time of presentation were included in the study. Of the cases, 40 % were pulmonary sarcoidosis, 7 % were pulmonary sarcoidosis with sarcoidosis of the lymph nodes, 8 % were lymph node sarcoidosis, 1 % were sarcoidosis, of other combined areas, and 40 % of the cases were sarcoidosis that were unspecified. The F/M of the cases were 947/353, and the average age of the cases was 44. When the sarcoidosis groups were grouped into NLR < 2 (Group 1) and NLR ≥ 2 (Gorup 2), 27 % were Group 1, 73 % were Group 2, and a significant correlation was found between the two groups. When the inflammatory indicators were compared with NLR, the PLT/MPV was found to be statistically insignificant, and the ACE, ESR and CRP were found to be statistically significant.

CONCLUSION

The Neutrophil/Lymphocyte ratio in the complete blood count, which is an easy and cheap test, can be used as an indicator of inflammation in Sarcoidosis. In clinical practice, wide-based studies comprising the activity and the staging in the prognosis of sarcoidosis are required (Tab. 2, Fig. 2, Ref. 26).

Chromosome and sister chromatid exchange studies in Behcet's patients

Behcet's disease is a chronic multisystemic disease of unknown pathogenesis characterized by four major symptoms: oral aphthous ulcers, skin lesions, ocular symptoms and genital ulcerations. The disease is spread throughout the world, but it is most frequent in Turkey, Japan, Korea and China. Although HLA-Bw51 has been found to predominate in Behcet's cases, the genetic etiology has not yet been clarified. In this study, we investigated the chromosomal abnormalities and sister chromatid exchange rates in patients with Behcet's diseases. Thirty-eight patients with Behcet's disease (diagnosed for the first time) and 30 healthy subjects (as controls) were included in this study. Although numerical and structural chromosomal abnormalities were not detected in our patients, we found an increased rate of sister chromatid exchange in patients over the control groups (P < 0.01). On the basis of these results, we discuss the genetic etiology of Behcet's disease.

Can N-terminal pro B-type natriuretic peptide, neutrophil-to-lymphocyte ratio, C-reactive protein help to predict short and long term mortality?

BACKGROUND

There is limited data about ICU, short and long-term mortality prediction of severe CAP with neutrophil-to-lymphocyte ratio (NLR): N-terminal proB- type natriuretic peptide (NT-proBNP): C-reactive protein (CRP).

AIM

Besides the known severity indexes of ICU, can NLR, NT-proBNP, CRP predict ICU, short and long term mortality?

METHODS

A retrospective cohort study was carried out in a level III ICU of a tertiary training hospital for chest diseases and thoracic surgery.

RESULTS

Over the study period, a total of 143 patients were enrolled in the study. The APACHE II scoring showed a significantly higher predicting performance for ICU mortality (p = 0.002). The performance for predicting short term mortality NLR (p = 0.039) and long term mortality NTproBNP (p = 0.002) had a significantly higher performance. The survival analysis revealed that mortality was significantly higher in patients with CURB65 score ≥ 4 (p = 0.047).

CONCLUSION

NLR, NTproBNP > 2000pg/mL can be used to predict pneumonia severity in ICU alike CURB65 and PSI. Higher NLR, APACHE II and atrial fibrillation can cause an important mortality factor in long term. Consequently, clinicians should take an attention for good cardiac evaluation and cardiac follow-up of patients with CAP (Tab. 4, Fig. 3, Ref. 36).

De novo terminal 4q deletion syndrome with new ocular findings in Turkish twins: case report

The 4q deletion syndrome is a rare chromosome deletion syndrome with a wide range of clinical phenotypes. Herein we report cases of twins (karyotype 46, XY) carrying terminal deletion of the chromosome 4 (q31qter) segment resulting in craniofacial dysmorphism, skeletal anomalies, ocular findings and cardiac defect.

A dysmorphic newborn with 45,X,der(1)inv(1)(p13;qter)t(Y;1)(pter-->q11;p13),-Y de novo karyotype

A dysmorphic newborn with 45,x,der(1)inv(1)(p13;qter)t(y;1)(pter-->q11;p13),-Y de novo karyotype: Y/autosome translocations are very rare chromosomal rearrangements. In most cases, the long arm of the Y chromosome is translocated onto an autosome and most patients are referred because of male infertility. Y/1 translocations are very rare, and have been reported in seven patients so far. Pericentric inversions may be seen in all chromosomes and are not associated with phenotypic abnormalities. Here we report a 6-day old male baby with prenatal growth retardation, frontal bossing, hypertelorism, micrognathia, cleft soft palate, absent uvula, hypospadias, simian line in both hands and hammer toes. Cytogenetic analysis was performed with GTG-banding, C-banding and FISH analysis containing X centromeric probe, Yq12-qter locus specific probe and whole chromosome Y probe. An unbalanced Y/1 translocation was diagnosed: 45,X,der(1)inv(1)(p13;qter)t(Y;1)(pter-->q11;p13),-Y.

Relationship between vitamin D deficiency and thrombus load in patients with ST-elevation myocardial infarction

OBJECTIVE

Clinical studies detecting the increase in thrombotic events with vitamin D deficiency note the relationship between vitamin D and thrombosis. This study aims at evaluating the relationship between serum vitamin D levels and coronary thrombus burden.

PATIENTS AND METHODS

We retrospectively evaluated 77 patients with ST-elevated myocardial infarction (STEMI). Serum vitamin D levels, degree of coronary thrombus, Thrombolysis in Myocardial Infarction (TIMI) frame count and the extent and severity of atherosclerosis in coronary arteries were also measured in all cases. Patients were divided into 2 groups, according to thrombus load.

RESULTS

The rate of vitamin D deficiency in the study population was 79.22% (< 20 ng/mL). Vitamin D levels were significantly higher in patients with a mild thrombus load than in patients with a severe thrombus load (16 vs. 13.95 p = 0.018). Gensini scores were significantly higher in patients with a severe thrombus burden than in patients with a mild thrombus burden (42 vs. 54.5 p = 0.014). There was a low negative correlation between vitamin D levels and thrombus burden classification grades (r = -0.304, p = 0.007), Cx TIMI frame counts (r = -0.402, p < 0.001), and RCA TIMI frame counts (r = -0.479, p < 0.001). There was a moderate negative correlation between serum vitamin D levels and LAD TIMI frame count (r = -0.507, p < 0.001).

CONCLUSIONS

The results of our study showed that low 25(OH)D3 levels are an independent predictor of high coronary artery thrombus load and post-procedural TIMI frame count increase in patients with STEMI undergoing primary percutaneous coronary intervention.