Significant association between nonsyndromic oral clefts and arylhydrocarbon receptor nuclear translocator (ARNT)

The etiology of nonsyndromic oral clefts (cleft lip, cleft palate, or cleft lip and palate) is still controversial, but is considered to involve both genetic and environmental factors. One of suspected environmental factors is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) found in tobacco, herbicides, contaminated soil, and food. TCDD administered during organogenesis in mice causes a high incidence of CP in fetuses. There is ample evidence that aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), and cytochrome P450 1A1 (CYP1A1) are involved in TCDD metabolism. We assessed whether there is any association in the Japanese population of nonsyndromic oral clefts with single nucleotide polymorphisms (SNPs) in the AHR, ARNT, and CYP1A1 genes using transmission disequilibrium test (TDT) and case-control study. We identified and investigated three SNPs in ARNT; 567G/C (V189V), IVS12-19T/G, and 2117C/T (P706L). Two amino acid substitutions, R554L in AHR and I462V in CYP1A1, were also investigated. In the TDT, the C allele of ARNT 567G/C was preferentially transmitted to patients (P = 0.033). When a haplotype consisting of 567G/C and IVS12-19T/G in ARNT was considered, the preferential transmission of the CT (567C-IVS12-19T) haplotype was observed (P = 0.0012). In a case-control study, a significant association of IVS12-19T/G in ARNT was observed (P = 0.021). The SNPs studied in AHR and CYP1A1 were not associated with the disease. Our results suggest that ARNT is involved in the development of nonsyndromic oral clefts in the Japanese population.     

The levels of cerebrospinal fluid Abeta40 and Abeta42(43) are regulated age-dependently

Decreased levels of cerebrospinal fluid (CSF) Abeta42 is a diagnostic marker of Alzheimer's disease. To clarify the biological basis of this marker, the physiological alterations of CSF Abeta40 and Abeta42 by aging were studied. CSF samples from 92 normal subjects between 8 and 89 years old were measured using a specific ELISA for Abeta40 and Abeta42(43). High concentrations of Abeta40 and Abeta42(43) in the young group, under 29 years old, changed to be at low concentrations in the adult group between 30 and 59 years old. Subsequently, the levels increased again with age. Third order regression analysis showed a significant correlation between the levels of Abeta40 and age (Y = - 169 X(3) + 3.1X(2)- 0.02X + 4135; P < 0.034) and between the levels of Abeta42(43) and age (Y = - 46 X(3) + 0.9 X(2)- 0.005X + 992; P < 0.005). The levels of CSF Abeta40 and Abeta42(43) were physiologically regulated to show a U-shaped natural course in normal aging. These findings suggested that the physiological increase of Abeta42(43) over 59 years of age is selectively inhibited in Alzheimer's disease.     

Role of apoptosis controlled by cytochrome c released from mitochondria for luteal function in human granulosa cells

PROBLEM: The aim of this study was to investigate the relationship between apoptosis by the mitochondrial pathway and luteal function in human granulosa cells. METHOD OF STUDY: Granulosa cells were obtained by ultrasound-guided follicular aspiration from patients undergoing in vitro fertilization and embryo transfer. After the addition of RU486, cells were stained with a mitochondria-specific fluorescent dye, MitoTracker Red CM x Ros. Using flow cytometry and National Institute of Health image, the mitochondrial fluorescent area was measured. After staining with Hoechst 33258 dye, the number of apoptotic bodies per 1000 cells were counted at random on photomicrographs. Homogenates were used for sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blot analysis using antibodies against cytochrome c or caspase-3. RESULTS: The incidence of apoptotic bodies increased and the mitochondrial membrane potential decreased time dependently. The opposite effect was observed dose dependently with RU486 treatment. Western blot analysis showed increased cytochrome c expression, after treatment with 1-2 microg/mL of RU486 which then decreased with 5-10 microg/mL of RU486. Caspase-3 expression increased dose dependently with RU486. CONCLUSIONS: These results suggest that the activation of caspase-3 caused by cytochrome c released from mitochondria plays an important role in apoptosis-related luteal function in human granulosa cells.     

Successful outcome with day 4 embryo transfer after preimplantation diagnosis for genetically transmitted diseases

Preimplantation genetic diagnosis was performed in 61 day 3 embryos obtained by in-vitro fertilization from seven patient carriers of haemophilia, Marfan's syndrome, Bloch-Sulzemberg syndrome (incontinentia pigmentosa) or X chromosome-linked immune deficiency, retinitis pigmentosa, and FG syndrome, which is characterized by mental retardation and hypotonia. After multiplex polymerase chain reaction, 16 embryos were diagnosed as being unaffected, and these were transferred to the uterus on the following day (day 4). Of these embryos, six (37.5%) implanted, resulting in the delivery of a singleton and a twin pregnancy, a late second trimester miscarriage (twins at week 20) and a first trimester miscarriage at week 8. All the diagnoses were confirmed by amniocentesis. We report for the first time a late day 4 transfer of biopsied human embryos undergoing preimplantation genetic diagnosis. This transfer schedule allows an extra day to perform genetic analyses on single blastomeres and to monitor any adverse effect of the biopsy procedure.      

Melanocytes in the nasal cavity and paranasal sinus. Incidence and distribution in Japan

Random, nonselected tissue specimens from 99 Japanese-20 cylindrically cut nasal blocks removed during autopsy (A.C., Autopsy Cases) and 79 cases removed during surgery, consisting of 32 chronic sinusitis cases (C.S.) and 47 nasal polyp cases (N.P.)-were examined histopathologically and electronmicroscopically with respect to distribution and frequency of melanocytes in the nasal cavity and paranasal sinus. Malignant melanoma cases were excluded. The overall incidence of positive cases for melanocytes revealed 21.2% (21 of 99 cases), with an incidence ratio of male to female of 0.9:1.0. Melanocytes were found beginning in the under 19 age group with incidence increasing proportionately with age. Peak incidence was in the 50-year age group at 50%. Melanocytes and melanotic cell foci were distributed in the stroma of the propria mucosa beneath the pseudostratified columnar epithelium and focused around the nasal and paranasal glands and sinuses. In 2 of the 21 cases positive for stromal melanocytes, intraepithelial melanocytes with dendritic processes were found. The histogenesis of malignant melanoma arising from the nasal cavity and paranasal sinus are also discussed in this study.     

THE PRESENCE OF INTRACYTOPLASMIC CONFRONTING CISTERNAE OF THE ENDOPLASMIC RETICULUM IN OSTEOSARCOMA CELLS IN INTERPHASE

Confronting cisternae of the endoplasmic reticulum recognized in tumor cells of 7 cases of osteosarcoma were presented. They were found in the mitotic cells as well as in the cytoplasms of interphase cells. The more the mitotic cells were observed in 1 μm-thick sections, the more frequently those membranous structures were encountered in the corresponding ultrathin sections. In the interphase cells, such structures were located around Golgi apparatus or close to the nucleus. Occasionally, they were composed of a pair of closely apposed cisternae of the nuclear membrane and the rough endoplasmic reticulum. These results seem to indicate that the nuclear envelope which is disrupted and reformed during mitosis in rapidly proliferating cells takes part in the formation of the confronting cisternae of the endoplasmic reticulum.     

Type-specific evolution of amyloid plaque and angiopathy in APPsw mice

To clarify how Aβ deposits start in the brain, we examined the early to late stages of senile plaques and amyloid angiopathy in APPsw mice. All types of human senile plaques were observed in the mouse brains. The premature forms of cored plaques appeared first in the cerebral cortex of mice at 7–8 months old. Then, amyloid angiopathy emerged, followed by diffuse plaques consisting of Aβ1–42. Modifications of the N-terminus of Aβ were late phase phenomena. The premature forms of cored plaques were composed of central Aβ1–40 amyloid cores, surrounding amorphous Aβ1–42 deposits, and accumulation of Aβ1–42 in some peripheral cells. These cells were incorporated in amyloid cores, and these plaques developed to large cored plaques composed of Aβ1–40 and Aβ1–42. The size and number of cored plaques were increased with age. These findings indicate different evolution paths for cored plaques and diffuse plaques, and suggest the presence of a pathway that initiates with the intracellular accumulation of Aβ1–42 and leads to the development of classic plaques in human brain tissues.     

Tuning of the porin expression under anaerobic growth conditions by his-to-Asp cross-phosphorelay through both the EnvZ-osmosensor and ArcB-anaerosensor in Escherichia coli

BACKGROUND: Widespread bacterial signal transduction circuits are generally referred to as 'two-component systems' or 'histidine (His)-to-aspartate (Asp) phosphorelays.' In Escherichia coli, as many as 30 distinct His-to-Asp phosphorelay signalling pathways operate in response to a wide variety of environmental stimuli, such as medium osmolarity and anaerobiosis. In this regard, it is of interest whether or not some of them together constitute a network of signalling pathways through a physiologically relevant mechanism (often referred to as 'cross-regulation'). We have addressed this issue, with special reference to the osmo-responsive EnvZ and anaero-responsive ArcB phosphorelay signalling pathways in E. coli. RESULTS: Under standard aerobic growth conditions, it is well known that the osmoregulatory profile of the outer membrane porins (OmpC and OmpF) is mainly regulated by the EnvZ-OmpR phosphorelay system in response to medium osmolarity. In this study, it was found that, under anaerobic growth conditions, E. coli cells exhibit a markedly altered expression profile of OmpC and OmpF This profile was significantly different from that observed for the cells grown aerobically. Results from extensive genetic studies showed that, under such anaerobic growth conditions, the arcB gene encoding the anaero-sensory His-kinase appears to be an auxiliary genetic determinant that regulates the expression profile of porins. We then provided several lines of in vivo and in vitro evidence, which taken together, supported the following conclusions. CONCLUSIONS: Under anaerobic growth conditions, porin expression is tuned not only by the authentic osmo-resposive EnvZ sensor, but also by the anaero-responsive ArcB sensor, in an OmpR-dependent manner. It is suggested that such ArcB-mediated cross-regulation plays a physiological role by integrating anaerobic respiratory signals into the porin regulation in E. coli anaerobiosis. The proposed model is a clear example of the interplay of two distinct His-to-Asp phosphorelay signalling pathways.