Oral Health and Swallowing Function of Nursing Home Residents.

OBJECTIVE: Although a good oral environment helps reduce the risk of pneumonia in the elderly, repeated pneumonia can occur even with frequent oral care. The actual risk of pneumonia during oral intake, the choice of whether oral intake is possible, and the choice of food form are often determined using video fluorography (VF), which can provide detailed information on swallowing function. However, few reports have compared the oral environment and swallowing function, leaving the relationship unclear. We examined the relationship between the oral environment and swallowing function and the characteristics of swallowing function in elderly nursing home residents. METHODS: The subjects were 48 elderly nursing home residents (13 males, 35 females) with a mean age of 89 years who underwent outpatient or inpatient evaluation of their oral environment and swallowing function. There were three groups of residents: those who were evaluated for swallowing as outpatients, those who were hospitalised for pneumonia, and those who were hospitalised for diseases other than pneumonia. The oral environment was assessed by a dentist or dental hygienist using the Oral Health Assessment Tool (OHAT). Swallowing function was assessed by an otorhinolaryngologist using VF. RESULTS: There was no correlation between OHAT and VF scores in the outpatient group or the group hospitalised for pneumonia, but there was a correlation in the group hospitalised for reasons other than pneumonia. CONCLUSION: In facilities with good oral care, the development of pneumonia may be related to factors other than the oral environment and the OHAT may reflect conditions other than swallowing function. The swallowing function of nursing home residents should be evaluated by VF, which allows observation of all stages of swallowing.

Evaluation of four computed tomography reconstruction algorithms using a coronary artery phantom.

Background: Despite advancements in coronary computed tomography angiography (CTA), challenges in positive predictive value and specificity remain due to limited spatial resolution. The purpose of this experimental study was to investigate the effect of 2nd generation deep learning-based reconstruction (DLR) on the quantitative and qualitative image quality in coronary CTA. Methods: A vessel model with stepwise non-calcified plaque was scanned using 320-detector CT. Image reconstruction was performed using four techniques: hybrid iterative reconstruction (HIR), model-based iterative reconstruction (MBIR), DLR, and 2nd generation DLR. The luminal peak CT number, contrast-to-noise ratio (CNR), and edge rise slope (ERS) were quantitatively evaluated via profile curve analysis. Two observers qualitatively graded the graininess, lumen sharpness, and overall lumen visibility on the basis of the degree of confidence for the stenosis severity using a five-point scale. Results: The image noise with HIR, MBIR, DLR, and 2nd generation DLR was 23.0, 21.0, 16.9, and 9.5 HU, respectively. The corresponding CNR (25% stenosis) was 15.5, 15.9, 22.1, and 38.3, respectively. The corresponding ERS (25% stenosis) was 203.2, 198.6, 228.9, and 262.4 HU/mm, respectively. Among the four reconstruction methods, the 2nd generation DLR achieved the significantly highest CNR and ERS values. The score of 2nd generation DLR in all evaluation points (graininess, sharpness, and overall lumen visibility) was higher than those of the other methods (overall vessel visibility score, 2.6±0.5, 3.8±0.6, 3.7±0.5, and 4.6±0.5 with HIR, MBIR, DLR, and 2nd generation DLR, respectively). Conclusions: 2nd generation DLR provided better CNR and ERS in coronary CTA than HIR, MBIR, and previous-generation DLR, leading to the highest subjective image quality in the assessment of vessel stenosis.

AMPK activation enhances osteoblast differentiation on a titanium disc via autophagy.

PURPOSE: The acquisition of osseointegration during implant therapy is slower and poorer in patients with diabetes compared with healthy persons. The serum concentration of adiponectin in patients with type II diabetes is lower than that of healthy persons via the suppression of AMP-activated protein kinase (AMPK). Therefore, we hypothesized that the AMPK activation enhances bone formation around implants, resulting in the improved acquisition of osseointegration. The purpose of this study was to evaluate the impact of AMPK activation on osteoblast differentiation and its mechanism of downstream signaling on titanium disc (Ti). METHODS: Confluent mouse pre-osteoblasts (MC3T3-E1) cells (1 × 105 cells/well) were cultured with BMP-2 for osteoblast differentiation, in the presence or absence AICAR, an AMPK activator. We examined the effects of AMPK activation on osteoblast differentiation and the underlying mechanism on a Ti using a CCK8 assay, a luciferase assay, quantitative RT-PCR, and western blotting. RESULTS: Although the proliferation rate of osteoblasts was not different between a Ti and a tissue culture polystyrene dish, the addition of AICAR, AMPK activator slightly enhanced osteoblast proliferation on the Ti. AICAR enhanced the BMP-2-dependent transcriptional activity on the Ti, leading to upregulation in the expression of osteogenesis-associated molecules. AICAR simultaneously upregulated the expression of autophagy-associated molecules on the Ti, especially LC3-II. AdipoRon, an adiponectin receptor type1/type2 activator activated AMPK, and upregulated osteogenesis-associated molecules on Ti. CONCLUSIONS: AMPK activation enhances osteoblast differentiation on a Ti via autophagy, suggesting that it promotes the acquisition of osseointegration during implant therapy.

CO2 Laser for Esthetic Healing of Injuries and Surgical Wounds with Small Parenchymal Defects in Oral Soft Tissues.

A number of studies have recently demonstrated the effectiveness of CO2 laser irradiation for the repair and regeneration of scar tissue from injuries or surgical wounds. However, such studies of the oral mucosa are highly limited. Previous studies using CO2 laser irradiation have indicated that two factors contribute to esthetic healing, namely, artificial scabs, which are a coagulated and carbonized blood layer formed on the wound surface, and photobiomodulation therapy (PBMT) for suppressing wound scarring and promoting wound healing. This review outlines basic research and clinical studies of esthetic healing with the use of a CO2 laser for both artificial scab formation by high-intensity laser therapy and PBMT in the treatment of injuries and surgical wounds with small parenchymal defects in oral soft tissues. The results showed that the wound surface was covered by an artificial scab, enabling the accumulation of blood and the perfusion necessary for tissue regeneration and repair. Subsequent PBMT also downregulated the expression of transformation growth factor-b1, which is involved in tissue scarring, and decreased the appearance of myofibroblasts. Taken together, artificial scabs and PBMT using CO2 lasers contribute to the suppression of scarring in the tissue repair process, leading to favorable esthetic and functional outcomes of wound healing.

Current status and factors of periodontal disease among Japanese high school students: a cross-sectional study.

INTRODUCTION: This study aimed to investigate the prevalence of periodontal disease and the factors of the disease among high school students. METHOD: The participants were all students aged 15-18 years (n = 1202) at a high school in Japan. The data on oral health perceptions and behaviours were collected by a questionnaire survey. The prevalence of periodontal disease among them was investigated with the partial community periodontal index (PCPI). A logistic regression analysis was used to identify the factors associated with the PCPI. RESULTS: A total of 1069 students (88.9%) participated in this study. The prevalence of gingival bleeding, calculus, pocket depth of 4-5 mm, and pocket depth of 6 mm or more were 44.2%, 42.2%, 11.4%, and 1.6%, respectively. Approximately one-third of the students had a fear of dental treatment, and only 28.4% used dental floss. The results of logistic regression analysis, adjusted for sex and school year, showed that not visiting dentists regularly, not using dental floss, brushing teeth for less than 5 min, fear of dental treatment, and drinking sports drinks frequently were positively associated with periodontal conditions. CONCLUSION: This study identified a high prevalence of periodontal disease among Japanese high school students aged 15-18 years and its risk factors, such as poor oral health behaviours and fear of dental treatment.

The effect of AMP kinase activation on differentiation and maturation of osteoblast cultured on titanium plate.

Background/purpose: 5' Adenosine monophosphate-activated protein kinase (AMPK) is known as an enzyme that maintains intracellular homeostasis and has various biological activity. The purpose of this study is evaluation effect of AMPK activation on implant prognosis. Materials & methods: MC3T3-E1 osteoblast-like cells were cultured on titanium using a 24-well plate. The experimental group was divided into the following 3 groups: (1) the normal culture group (control group), (2) the osteogenic induction group, and (3) the osteogenic induction + AMPK activation group. The cell counts were measured; real-time PCR was used to assess the expression of ALP and Osterix as osteogenic related genes at Day 0,7,14 and 21 after experiments. Additionally, ALP activity and calcification were assessed. Results: The results of the real-time PCR assessments revealed that the expression of ALP, which is a marker for the initial stages of calcification, was significantly increased by AMPK activation compared to the normal culture or osteogenic induction. A significant increase was also observed in the expression of Osterix, which is a marker for the later stages of calcification. Because significant increases were observed in ALP activity and calcification potential, this suggested that AMPK activation could elicit an increase in osteoblast calcification potential. Conclusion: AMPK activation promotes implant peripheral osteoblast differentiation and maturation and enhances calcification. Our results suggest that AMPK activation may help to maintain implant stability.

Space-making effect for new bone formation by suppressing scar contraction of mucosal epithelium of rat tooth extraction wound using diode laser and CO2 laser treatment.

Background/purpose: As an extraction wound closes, the mucosal epithelium of the tooth extraction wound impedes the space for new bone formation by invading into the extraction socket. Thus, the height of the alveolar crest decreases, causing significant depression of the alveolar mucosa. In this study, we created a rat tooth extraction model and examined the effects of laser irradiation by CO2 and diode on the dynamics of myofibroblast expression through α-SMA, and TGF-ß1. Materials and methods: After tooth extraction of five-week-old male Wistar rats, they were divided into two laser treatment groups (CO2 laser or diode laser was irradiated into tooth extraction socket) and non-laser treatment group (control group). Surrounding tissues, including the extraction socket, were removed at 3, 5, 7, and 21 days after tooth extraction and the expression of α-SMA and TGF-ß1 was verified using immunohistological techniques (6 animals in each group and each period, 72 animals in total). Results: α-SMA-positive cells and TGF-ß1-positive areas were significantly lower in the two laser treatment groups than in the control group. Particularly, the diode group almost had no TGF-ß1-positive areas on the 21st day when healing after tooth extraction was deemed to be completed. Conclusion: Both CO2 and diode laser irradiation of tooth extraction wounds decreases α-SMA-positive cells and TGF-ß1-positive areas. Further, it causes a decrease in myofibroblast expression and suppresses the invasion of mucosal epithelium into the extraction socket. Therefore, laser irradiation may exert a space-making effect for new bone formation and also contribute to socket preservation.

Occlusal disharmony transiently decrease cognition via cognitive suppressor molecules and partially restores cognitive ability via clearance molecules.

Occlusal disharmony has been reported to be affected not only by cytokine and steroid hormone secretion and sympathetic activation in peripheral organs, but also by neurotransmitter release in the central nervous system. However, little is known about whether occlusal disharmony can decrease cognitive ability. We hypothesized that hyperocclusion decreases cognition via Alzheimer's disease-associated molecule expression in the brain. The present study is aimed to elucidate the relationships among occlusal disharmony, cytokine and cognitive-regulated molecule expression in the brain, and the impairment of learning and memory cognition. We examined the effect of hyperocclusion on the relationships among cytokine expression, cognitive suppressor molecules in the hippocampus, and cognition in behavior using a hyperocclusion mouse model. Hyperocclusion dramatically increased interleukin-1ß expression in the serum and hippocampus 1 week after hyperocclusal loading in 2-month-old mice, but no effects in 12-month-old mice. The social and long-term cognitive abilities of the 2-month-old mice were transiently downregulated close to the level of the 12-month-old mice 1 week after hyperocclusion and recovered to close to basal level via the expression of cognitive suppressor clearing proteins. The expression levels of amyloid-ß and phosphorylated tau were significantly upregulated 1 week after hyperocclusal loading in the hippocampus of 2-month-old mice but were constant in 12-month-old mice. Occlusal disharmony-induced interleukin-1ß expression may contribute to accumulation of cognitive suppressor molecules such as amyloid-ß and phosphorylated tau and activate their clearance proteins, resulting in protection against transient dementia in young but not older individuals.

Comparison of visibility of in-stent restenosis between conventional- and ultra-high spatial resolution computed tomography: coronary arterial phantom study.

PURPOSE: The purposes of this experimental study were to compare the quantitative and qualitative visibility of in-stent restenosis between conventional-resolution CT (CRCT) and ultra-high-resolution CT (U-HRCT) and to investigate the effects of the image reconstruction techniques on the visualization of in-stent restenosis. MATERIALS AND METHODS: A vessel tube with non-calcified plaque in a 3.0-mm stent was scanned by using CRCT and U-HRCT at 4 stent directions (0, 30, 60, and 90 degrees) to the through-plane direction. Hybrid iterative reconstruction (HIR); model-based iterative reconstruction (MBIR); deep-learning-based reconstruction (DLR) were used as reconstruction methods. The lumen size was assessed using the full width at half maximum method, and image quality was visually evaluated using 4-point scale. RESULTS: U-HRCT had the significantly wider lumen sizes and narrower stent strut thickness than CRCT in three types of the reconstruction methods (P < 0.01). The lumen sizes for U-HRCT with 90 degrees were narrower than those with the other angle directions regardless of the reconstruction methods. Visual score was significantly higher for U-HRCT than CRCT (3.2 ± 0.7 vs 2.0 ± 0.4, P < 0.001). CONCLUSIONS: U-HRCT quantitatively and qualitatively provided better visualization of in-stent restenosis compared to CRCT. Image quality of U-HRCT may be affected by stent angle.

Radiology- and gene-based risk stratification in small renal cell carcinoma: A preliminary study.

PURPOSE: Most small renal cell carcinomas (small RCCs) will remain indolent after detection, but some stage I RCCs still metastasize. There are no risk-stratification imaging factors that could be used to identify poor-prognosis patients based on genomic profiling. Here, we evaluated the relationships between imaging parameters and RNA expressions in small RCC and attempted to identify imaging factors that could be used as effective biomarkers. METHODS: We acquired biopsy specimens of 18 clear cell carcinomas that had undergone perfusion CT (pCT) and MRI between April 2018 and March 2019. We performed RNA sequencing, assessed RNA expressions, and calculated each tumor's cell-cycle progression (CCP) score, which has prognostic value in predicting metastatic progression. We classified the tumors into two groups: clear cell type A (ccA) and type B (ccB). CcA has better survival compared to ccB. We evaluated the following characteristics of each tumor: tumor size, presence of pseudocapsule, and fat. We used the pCT and MRI to measure each tumor's volume transfer constant (Ktrans), rate constant (Kep), extracellular extravascular volume fraction (VE), fractional plasma volume (VP), and apparent diffusion coefficient (ADC). The correlations between these small RCC imaging parameters and the tumor size and RNA expressions were determined. RESULTS: The tumor size was significantly correlated with Kep and inversely correlated with VE, VP, ADC, and hallmark angiogenesis. The CCP score was significantly inversely correlated with Ktrans and Kep. The ccA tumors tended to show a pseudocapsule on MRI. CONCLUSION: Tumor size was correlated with low perfusion, but not with prognostic factors based on genomic profiling. Imaging parameters (e.g., Ktrans and Kep) and tumor characteristics (e.g., pseudocapsule) may enable gene-based risk stratification in small RCC.

Preliminary study of time maximum intensity projection computed tomography imaging for the detection of early ischemic change in patient with acute ischemic stroke.

Noncontrast computed tomography (NCCT) has been used for the detection of early ischemic change (EIC); however, correct interpretation of NCCT findings requires much clinical experience. This study aimed to assess the accuracy of time maximum intensity projection computed tomography technique (tMIP), which reflects the maximum value for the time phase direction from the dynamic volume data for each projected plane, for detection of EIC, against that of NCCT.Retrospective review of NCCT, cerebral blood volume in CT perfusion (CTP-CBV), and tMIP of 186 lesions from 280 regions evaluated by Alberta Stroke Program Early CT Score (ASPECTS) in 14 patients with acute middle cerebral artery stroke who had undergone whole-brain CTP using 320-row area detector CT was performed. Four radiologists reviewed EIC on NCCT, CTP-CBV, and tMIP in each ASPECTS region at onset using the continuous certainty factor method. Receiver operating characteristic analysis was performed to compare the relative performance for detection of EIC. The correlations were evaluated.tMIP-color showed the best discriminative value for detection of EIC. There were significant differences in the area under the curve for NCCT and tMIP-color, CTP-CBV (P < .05). Scatter plots of ASPECTS showed a positive significant correlation between NCCT, tMIP-gray, tMIP-color, and the follow-up study (NCCT, r = 0.32, P = .0166; tMIP-gray, r = 0.44, P = .0007; tMIP-color, r = 0.34, P = .0104).Because tMIP provides a high contrast parenchymal image with anatomical and vascular information in 1 sequential scan, it showed greater accuracy for detection of EIC and predicted the final infarct extent more accurately than NCCT based on ASPECTS.

Micro-computed tomography for evaluating alveolar bone resorption induced by hyperocclusion.

PURPOSE: Occlusal trauma, resulting in the destruction of alveolar bone, is a form of periodontal disease caused by excessive mechanical stress (MS) during hyperocclusion. Previously, we showed that CC chemokine ligand (CCL) 2/CCR2 receptor axis plays a crucial role in MS-dependent osteoclastogenesis. However, in the previous work, we were unable to precisely measure changes in alveolar bone profiles. In the present study, we sought to establish a precise method for evaluating alveolar bone resorption induced by hyperocclusion using micro-computed tomography. METHODS: Under anesthesia, a stainless steel wire was attached to the molars of 5-week-old C57/BL6 wild-type (WT) mice, CCL2-/- mice, and CCR2-/-mice to induce occlusal force overload. At days 0 and 7, hard tissue samples were harvested and analyzed by micro-computed tomography. RESULTS: In the WT mice, bone mineral density of the alveolar bone was significantly decreased at day 7 as compared with day 0, with marked alveolar bone resorption observed. Similarly, significant alveolar bone resorption was observed in the CCL2-/- and CCR2-/- mice at day 7 as compared with day 0. CONCLUSIONS: Micro-computed tomographic images can be used to measure changes in bone mineral density in a mouse model of hyperocclusion. This method may be useful for further investigating bone changes in other periodontal disease research fields.

Hyperocclusion stimulates the expression of collagen type XII in periodontal ligament.

OBJECTIVES: It is known that excessive mechanical force exerted by hyperocclusion induces occlusal trauma. However, the mechanism of the process remains unclear. In the present study, we employed an in vivo hyperocclusion rodent model to examine morphological and biological mechanisms of occlusal trauma in periodontal ligament tissue. DESIGN: To investigate alveolar bone resorption, tooth sections were stained to detect osteoclasts. To investigate the relationship between hyperocclusion and the regeneration of the cell matrix, we examined the effect of hyperocclusal force on the expression of collagens using immunohistochemistry and quantitative PCR methods. RESULTS: The arrangement of collagen fibers in the furcation area of the teeth was undisturbed before hyperocclusion (control). Type I collagen was localized in the extracellular area at the furcation and there was faint expression and localization of type XII collagen in the periodontal ligament. The number of osteoclasts significantly increased in the furcation and lingual cervical regions on day 4 after hyperocclusion was induced. Type XII collagens were gradually up-regulated following the induction of hyperocclusion, in a time-dependent manner. Although type I collagen mRNA expression was stable before and after hyperocclusion, type XII collagen mRNA was significantly up-regulated on day 2 and day 4 after hyperocclusion treatment. CONCLUSIONS: Our findings indicate that hyperocclusal force predominantly up-regulates the expression of type XII collagen in periodontal tissue, but not type I collagen, suggesting that there is a mechanism for regeneration of periodontal tissues as a response to occlusal trauma.

Photothermal stress triggered by near-infrared-irradiated carbon nanotubes up-regulates osteogenesis and mineral deposition in tooth-extracted sockets.

PURPOSE: The bone regenerative healing process is often prolonged, with a high risk of infection particularly in elderly and diseased patients. A reduction in healing process time usually requires mechanical stress devices, chemical cues, or laser/thermal therapies. Although these approaches have been used extensively for the reduction of bone healing time, the exact mechanisms involved in thermal stress-induced bone regeneration remain unclear. METHODS: Photothermal stress (PTS) stimulation was carried out using a novel photothermal device, composed of an alginate gel (AG) including carbon nanotubes (CNT-AGs) and their irradiator with near-infrared (NIR) light. We investigated the effects of optimal hyperthermia on osteogenesis, its signalling pathway in vitro and mineral deposition in tooth-extracted sockets in vivo. RESULTS: The PTS (10 min at 42 °C, every day), triggered by NIR-induced CNT, increased the activity of alkaline phosphatase (ALP) in mouse osteoblast MC3T3-E1 cells in a time-dependent manner compared with the non-thermal stress control. PTS significantly induced the expression of osteogenic-related molecules such as ALP, RUNX2 and Osterix in a time-dependent manner with phosphorylated mitogen-activated protein kinases (MAPK). PTS increased the expression of heat shock factor (HSF) 2, but not HSF1, resulting in activation of heat shock protein 27. PTS significantly up-regulated mineral deposition in tooth-extracted sockets in normal and ovariectomised osteoporotic model mice in vivo. CONCLUSIONS: Our novel CNT-based PTS up-regulated osteogenesis via activation of heat shock-related molecules, resulting in promotion of mineral deposition in enhanced tooth-extracted sockets.

The potential role of transient receptor potential type A1 as a mechanoreceptor in human periodontal ligament cells.

Transient receptor potential type A1 (TRPA1) is reported to be a Ca(2+) -permeable channel and is activated by cold temperatures and mechanical stimuli in the hair cells and in dorsal root ganglion. Using a DNA microarray, we found that TRPA1 was significantly up-regulated in human periodontal ligament (hPDL) cells 2 d after intermittent mechanical stimulation (iMS) loading compared with unloaded cells. Although hPDL cells are known to respond to mechanical stimulation induced by occlusal force, little is known about the expression and functional role of TRPA1 in these cells. Therefore, we investigated the effects of iMS on TRPA1 expression and its signaling pathway in hPDL cells. Intermittent mechanical stimulation loading up-regulated TRPA1 expression in hPDL cells in a time-dependent manner, but had no effect on other mechanoreceptors. Furthermore, iMS significantly increased the phosphorylation of mitogen-activated protein kinases (MAPKs), especially extracellular signal-regulated kinase 1/2 (ERK1/2) and p38, and the expression of C-C chemokine ligand 2 (CCL2). Transient receptor potential type A1 agonists also increased MAPK phosphorylation and the intracellular Ca(2+) concentration. By contrast, inhibition or silencing of TRPA1 partially suppressed iMS-induced MAPK phosphorylation. In summary, iMS during occlusion activates TRPA1 and MAPK signaling in periodontal ligament tissues, suggesting that TRPA1 regulates the mechanosensitivity of occlusal force via activation of MAPKs in hPDL cells.

Association between affective temperaments and brain-derived neurotrophic factor, glycogen synthase kinase 3ß and Wnt signaling pathway gene polymorphisms in healthy subjects.

BACKGROUND: There is increased attention towards elucidating genetic factors that underlie both psychiatric diseases as well as healthy psychological phenomena. Recent evidence suggests that temperamental traits, including affective temperaments, are heritable and associated with genetic polymorphisms. Genetic research examining affective temperaments using the Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A) may therefore elucidate the concept of a spectrum of mood disorders and the genetic relationship between affective temperaments and mood disorders. The purpose of this study was to examine the association between brain-derived neurotrophic factor (BDNF), glycogen synthase kinase 3ß(GSK3ß) and Wnt signaling pathway (Wnt) gene polymorphisms and affective temperaments in non-clinical Japanese subjects, as measured by TEMPS-A. METHODS: 44 healthy Japanese subjects were recruited through our university hospital and completed the TEMPS-A. We genotyped three SNPs (single nucleotide polymorphisms) from the BDNF, GSK3ßand Wnt genes in order to test the relationship between these gene variants and five affective temperaments measured by the TEMPS-A. RESULTS: No significant difference in the frequency of alleles between affective temperaments (depressive, cyclothymic, hyperthymic, irritable and anxious temperament) and non affective temperaments was shown. One-way analysis of variance (ANOVA) revealed no significant differences among 5 groups (depressive, cyclothymic, hyperthymic, irritable and anxious temperament) in healthy subjects for all the scores of affective temperaments by TEMPS-A. LIMITATIONS: The number of subjects was relatively small. CONCLUSIONS: The variant of BDNF, GSK3ß and Wnt gene polymorphism might not be related to the five temperaments of TEMPS-A and TEMPS-A score in healthy Japanese subjects. The present results suggest that BDNF, GSK3ßand Wnt genes, might not have a major role in the development of personality traits. Further studies with larger sample size are warranted to evaluate the association of affective temperament and gene polymorphisms.

Asymmetric autocatalysis triggered by carbon isotope (13C/12C) chirality.

Many apparently achiral organic molecules on Earth may be chiral because of random substitution of the 1.11% naturally abundant 13C for 12C in an enantiotopic moiety within the structure. However, chirality from this source is experimentally difficult to discern because of the very small difference between 13C and 12C. We have demonstrated that this small difference can be amplified to an easily seen experimental outcome using asymmetric autocatalysis. In the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc, addition of chiral molecules in large enantiomeric excess that are, however, chiral only by virtue of isotope substitution causes a slight enantiomeric excess in the zinc alkoxide of the produced pyrimidyl alkanol. Asymmetric autocatalysis then leads to pyrimidyl alcohol with a large enantiomeric excess. The sense of enantiomeric excess of the product alcohol varies consistently with the sense of the excess enantiomer of the carbon isotopically chiral compound.

Social support and enhanced suppression of adrenocorticotropic hormone and cortisol responses to hypothalamic-pituitary-adrenal function and thyrotropin-releasing hormone tests in patients with major depressive disorder.

The results of the thyrotropin-releasing hormone (TRH) stimulation test and the combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) test are believed to correlate with social support status in patients with major depressive disorder. We studied 41 consecutive patients hospitalized for major depressive disorder and tested their responses to DEX/CRH and TRH on hospital days 4-7. DeltaMAX TSH and DeltaMAX cortisol were measured. Multiple regression analysis found that social support questionnaire (SSQ-A) and SSQ-B scores were significantly related to DeltaMAX cortisol and DeltaMAX TSH, respectively, at the time of admission. Social support might contribute partially to the TRH and DEX/CRH test results in patients with major depressive disorder.

Chiral discrimination of cryptochiral saturated quaternary and tertiary hydrocarbons by asymmetric autocatalysis.

Chiral discrimination of saturated hydrocarbons has been very difficult to establish, or has not been possible at all. The first chiral discrimination of cryptochiral 5-ethyl-5-propylundecane 1, that is, (n-butyl)ethyl(n-hexyl)(n-propyl)methane, a chiral saturated quaternary hydrocarbon, which is known to exhibit practically no detectable value of optical rotation between 280 and 580 nm, has been accomplished by asymmetric autocatalysis of pyrimidyl alkanol. The absolute configuration of 1 has been determined. In the presence of (R)- or (S)-1, the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc affords (S)- and (R)-pyrimidyl alkanol with 91-97% ee, respectively. Thus, asymmetric autocatalysis serves as a powerful tool for the chiral discrimination of saturated hydrocarbons.