Approach to the "Missing" Diarylsilylene: Formation, Characterization, and Intramolecular C-H Bond Activation of Blue Diarylsilylenes with Bulky Rind Groups

The treatment of the bulky Rind-based dibromosilanes, (Rind)2SiBr2 (2) [Rind = 1,1,7,7-tetra-R1-3,3,5,5-tetra-R2-s-hydrindacen-4-yl: EMind (a: R1 = Et, R2 = Me) and Eind (b: R1 = R2 = Et)], with two equivalents of tBuLi in Et2O at low temperatures resulted in the formation of blue solutions derived from the diarylsilylenes, (Rind)2Si: (3). Upon warming the solutions above -20 °C, the blue color gradually faded, accompanying the decomposition of 3 and yielding cyclic hydrosilanes (4) via intramolecular C-H bond insertion at the Si(II) center. The molecular structures of the bulky Eind-based 3b and 4b were confirmed by X-ray crystallography. Thus, at -20 °C, blue crystals were formed (Crystal-A), which were identified as mixed crystals of 3b and 4b. Additionally, colorless crystals of 4b as a singular component were isolated (Crystal-B), whose structure was also determined by an X-ray diffraction analysis. Although the isolation of 3 was difficult due to their thermally labile nature, their structural characteristics and electronic properties were discussed based on the experimental findings complemented by computational results. We also examined the hydrolysis of 3b to afford the silanol, (Eind)2SiH(OH) (5b).

Selective monooxygenation of diphosphenes with molecular oxygen

The O2 splitting mediated by the bulky Rind-based diphosphenes resulted in the clean formation of the mixed-valent diphosphorus compounds, diphosphene oxides, with P2O moieties. Their structural features and electronic properties have been clearly characterized by experimental and theoretical methods.

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

A series of (E)-1,2-diaryldigermenes incorporating bulky Eind groups: structural characteristics and absorption properties

A series of (E)-1,2-diaryldigermenes, (Eind)ArGeGeAr(Eind) [Ar = phenyl (2), thiophen-2-yl (3), 9,9-dimethyl-2-fluorenyl (4) and 2,2'-bithiophen-5-yl (5)], supported by the fused-ring bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups, have been obtained as yellow-orange to red crystalline solids by the reaction of 1,2-dibromodigermene, (Eind)BrGeGeBr(Eind) (1), with ArLi. In the crystals of 2-5, the digermene cores show a flexible nature adopting a trans-bent geometry with the trans-bent angles (θ) between the Ge-Ge vector and the C_Eind-Ge-C_Ar plane of 34.04(12)° (2), 38.3(3)° and 38.8(3)° (3), 33.69(12)° (4) and 39.30(13)° (5). In the UV-vis spectra, strong π-π* absorptions have been observed with an absorption maximum at 451 nm (ε = 1.3 × 10⁴) (2), 455 nm (ε = 9.7 × 10³) (3), 480 nm (ε = 1.3 × 10⁴) (4) and 497 nm (ε = 1.4 × 10⁴) (5), retaining the GeGe double bond in solution. The absorption data and DFT calculations provide evidence for the intrinsic π-conjugation between the GeGe chromophore and aromatic rings involving the narrowing of the HOMO-LUMO gaps (ΔE) with the extension of the carbon π-electron systems.

Heavier element-containing aromatics of [4n+2]-electron systems

While the implication of the aromaticity concept has been dramatically expanded to date since its emergence in 1865, the classical [4n+2]/4n-electron counting protocol still plays an essential role in evaluating the aromatic nature of compounds. Over the last few decades, a variety of heavier heterocycles featuring the formal [4n+2] π-electron arrangements have been developed, which allows for assessing their aromatic nature. In this review, we present recent developments of the [4n+2]-electron systems of heavier heterocycles involving group 13-15 elements. The synthesis, spectroscopic data, structural parameters, computational data, and reactivity are introduced.

P–651 Strict embryo-endometrial synchrony does not contribute to the successful pregnancy during vitrified-warmed embryo transfer with hormone replacement cycles

Study question

Does strict embryo-endometrium synchronization relate to pregnancy during vitrified-warmed embryo transfer (ET) with hormone replacement (HRT) cycles?

Summary answer

A 12-hour delay in the embryo-endometrial synchrony was acceptable, and this delay was not an independent predictor of pregnancy during vitrified-warmed ET with HRT cycles.

What is known already

Embryo-endometrium synchrony is considered to be necessary for successful pregnancy in both fresh and frozen-thawed cycles. Until now, the date of ET has been determined by the synchronization of the embryo developmental stage and the endometrium on a daily basis. To date, with the advent of the time-lapse incubator, it is possible to observe the embryo development from fertilization over time and to calculate the exact time from fertilization of the transferred embryo. However, there are very few studies on the extent to which increases the accuracy of synchronization between embryo and endometrium contributes to a successful pregnancy.

Study design, size, duration

This retrospective cohort study included 319 consecutive cycles during vitrified-warmed ET with HRT between August 2016 and August 2018. This study was conducted in an academically affiliated private practice.

Participants/materials, setting, methods

We analyzed 319 vitrified-warmed single-blastocyst transfer cycles. All frozen expanded blastocysts were inseminated by intracytoplasmic sperm injection (ICSI) and cultured in a time-lapse incubator. We calculated time for the in vitro culture of the embryo after ICSI (t1) and time for progesterone-priming (t2) up to ET. The difference between t1 and t2 (delta-t) was used as an indicator of embryo-endometrium synchrony. We examined the relationship between delta-t and treatment outcomes using multivariate logistic analysis.

Main results and the role of chance

The mean patient’s age at oocyte retrieval was 35.7 (SD 4.3). The number of pregnant cycles was 157 in all treatment cycles (pregnancy rate, 49.2%). The mean value of delta-t was 9.9 h (SD 2.6) in all cycles. There was no significant difference of delta-t in pregnant (mean, SD: 10.0 h, 2.8 h) and non-pregnant cycles (mean, SD: 10.0 h, 2.3 h). Treatment cycles were classified according to the quartile of delta-t, and we examined the percentages of pregnant cycles in each group. There were no significant differences in pregnancy rates among the groups (p = 0.75). On multivariate logistic analysis, patient’s age (adjusted odds ratio [aOR]: 0.94, 95% confidence interval [CI]: 0.89–0.99), previous treatment cycles (aOR: 0.74, 95% CI: 0.56–0.99), endometrial thickness at ET (aOR: 1.19, 1.04–1.36), and good quality blastocysts (>3BB according to Gardner’s classification) at vitrification (aOR: 2.49, 95% CI: 1.23–5.05) were independent predictive factors for pregnancy. On the other hand, delta-t did not contribute to pregnancy (aOR: 1.00, 95% CI: 0.99–1.00).

Limitations, reasons for caution

We did not examine the effects of embryo-endometrium synchrony during vitrified-warmed ET in a natural cycle. Therefore, careful interpretation of the significance of embryo-endometrium synchrony during the vitrified-warmed ET should be taken.

Wider implications of the findings: We showed the embryo-endometrium synchrony did not contribute to the pregnancy during vitrified-warmed ET with HRT cycles. These results cast doubt on the existence of an optimal implantation window by changing the timing of ET with the results of gene expression testing of the endometrium.

Trial registration number

Not applicable

A Crystalline B4N2 Dewar Benzene as a Building Block for Conjugated B,N-Chains

Dewar benzene, one of the isolable valence isomers of C₆H₆, has been extensively studied since its first synthesis in 1962. By contrast, the chemistry of inorganic congeners of Dewar benzene, which can be formally gained by replacing the skeletal carbon atoms with heteroatoms, has been less developed despite their peculiar structural and electronic features. Among them, the extant B,N-Dewar benzenes are limited to the B₃N₃ system. Herein, we report the development of the first example of an isolable B₄N₂ Dewar benzene, 3. As predicted by DFT calculations, a judicious selection of the substituents allows synthesizing 3. Single-crystal X-ray analysis, NMR, and computational studies confirmed that 3 possesses a high-lying B(sp³)-B(sp³) σ-bond at the bridgehead position. Reactions with ethylene and phenylacetylene proceeded smoothly under mild conditions, affording the fused B₄C₄N₂ ring systems (4 and 5). Structural characterization as well as DFT calculations revealed that compounds 4 and 5 involve a rigid and conjugated (BN)₄ tetraene scaffold. Formation of 4 and 5 demonstrates that 3 may serve as a building block for the construction of conjugated B,N-chains.

Aromatic nature of neutral and dianionic 1,4-diaza-2,3,5,6-tetraborinine derivatives

The aromatically relevant parameters of boron-rich inorganic benzenes-neutral and dianionic 1,4-diaza-2,3,5,6-tetraborinine derivatives (B4N2R6)-have been computationally estimated and evaluated from geometric, electronic, magnetic, and energetic points of view. The majority of the criteria (ASE, NICSzz, ELF, and PDI) indicate that the aromaticity of the neutral B4N2 benzene analogue stabilized by Lewis bases lies in between those of benzene and borazine. On the other hand, the aromaticity of the dianionic B4N2 benzene analogue 4' is controversial. The pronounced aromatic nature of 4' is supported by ELFπ, PDI, and NICSπzz, but ASE, the FiPC-NICS plot, and ACID oppose this. These data confirm that even with the same B4N2-skeletal framework of a 6π-system, the aromatic feature varies depending on the overall charge of the B4N2 systems.

Online survey of genital and urinary symptoms among Japanese women aged between 40 and 90 years

OBJECTIVE

The purpose of this survey was to assess the prevalence of genital and urinary tract symptoms among Japanese women with declining estrogen levels.

METHODS

A health-related questionnaire survey was conducted among women in their 40s or older to inquire about their genital, intercourse-related, and urinary symptoms and concern over their symptoms.

RESULTS

Of the consecutive 10,000 respondents recruited, 4488 (44.9%) reported having symptoms: 3546 (79.0%) expressed concern over their symptoms. Furthermore, 2173 women (21.7%) had incontinence, 1999 (20.0%) had urinary frequency, 1648 (16.5%) had itching, and 1560 (15.6%) reported odor; these were followed by looseness, dryness, and burning. Of the 2518 (25.2%) sexually active women, 518 (20.6%) reported having dyspareunia and more reported having urinary symptoms than genital symptoms. Of the symptomatic respondents, 33.1% had genital symptoms alone, 28.4% had urinary symptoms alone, and 38.4% had both. More sexually active women had genital symptoms, while more sexually inactive women had urinary symptoms.

CONCLUSIONS

Genital and urinary symptoms were shown to be common and coexist in a considerable proportion of the respondents, highlighting the pathology of genitourinary syndrome of menopause. Again, dyspareunia and lower urinary tract symptoms were shown to be quite common among postmenopausal women.

Germylone-bridged bimetallic Ir and Rh complexes

The reactions of germylone 1 with one equivalent of [M(COD)Cl]₂ (M = Ir, Rh) afforded the germylone-bridged bimetallic complexes 2 and 3, which have been spectroscopically and structurally characterized.

Construction and usability of community health nursing database in rural north-eastern Thailand

INTRODUCTIONS

Digitization could be incorporated in rural areas of resource-poor countries because information gathered by nurses working on-site could be better used.

BACKGROUND

For effective management of community health information, the usage and maintenance of digital records are important. Digitization of information provides essential information for informing health policy.

AIM

To develop a sustainable database to effectively collect and manage community health information and nursing practice.

METHODS

This study used a mixed method design. Phase 1 involved the development of a database system through repeated systematic focus group discussions with community health nurses. Phase 2 involved a practical trial examination of the developed system with both objective and subjective evaluations.

RESULTS

A nursing database system was developed with templates designed for the major health problems of communities. The templates were composed of multiple-choice items and a free-text field that allowed records to be more detailed than handwritten records and maintained in standardized formats. This enables accumulation of data that were less likely to be influenced by the variance of ability in each nurse.

DISCUSSION AND CONCLUSION

A multifaceted evaluation of the database system suggested that it could improve the efficiency of information management and contribute to the improvement of nursing care quality through standardization of the recording pattern.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

The nursing database will enable high-quality information storage that will potentially better inform health and healthcare policies as well as enable visualization of data concerning nursing care challenges and activities within the relevant communities. This information is essential for policy development and implementation in areas of human and fiscal resource allocations and meeting training/education needs.

Clinical Effect of Recombinant Human Erythropoietin on Anemia Associated with Chronic Renal Failure. A Multiinstitutional Study in Japan

Clinical effect and safety of recombinant human erythropoietin (r-HuEPO) were evaluated in 66 hemodialysis patients with intractable anemia. Initially, 50U/kg dry weight (DW) of r-HuEPO was administered intravenously at the end of every hemodialysis procedure for 4 weeks, then the dosage was increased to 100 and 200U/kg DW for poor responders. The patients’ hematocrits rose from 19.8 ± 2.3% (pretreatment) to 30.2 ± 4.9% after 12 weeks. From 206 U of blood transfusion requirement in the 3-month period before the study, only 34 U were needed after treatment. Serum iron and ferritin levels fell significantly during the study, and iron storage was considered to be one of the decisive factors in the response to r-HuEPO. Blood pressure rose in the course of r-HuEPO administration, but uncontrollable hypertension was rarely observed. There was no significant adverse effect of r-HuEPO except for this mild hypertension. These results indicate that r-HuEPO is an excellent therapeutic aid for the anemia associated with chronic renal failure.

Effect of Membrane Trapping in Plasma Fractionator on Separative Characteristics

Several kinds of plasma fractionators have been introduced to actively separate protein fractions between albumin and globulins in double filtration plasmapheresis. However, relatively large molecular weight proteins are known to be partially trapped by the membrane in a plasma fractionator.

In this paper, effects of membrane trapping on separation characteristics in plasma fractionators were examined during in vitro and in vivo studies. All in vitro experiments were done with a closed circuit under constant-flow rate filtration. Protein concentration in feed tank kept constant at no filtration in AS-14H, Evaflux 4A and 2A, while 20-40% of IgG and 40-60% of β-lipoprotein in 2 liter plasma were removed by membrane trapping for 300 min when filtration fraction equaled 0.87. Protein plugging to the membrane seems to be a major factor in these proteins. And, Dead-end and Partially Discarded modalities with relatively high filtration fraction are effective for the separation between albumin and globulin.

Twenty-seven DFPP treatments in 13 patients with autoimmune diseases were done to allow us to estimate the effects of membrane trapping during an in vivo study. All treatments using 6 types of plasma fractionator were performed under constant operating conditions with Partially Discarded modality. In any plasma fractionator, β-lipoprotein was fairly trapped at 30 min after the start of treatment.

Microscopic Observation of Leukocyte Kinesis in the Vascular Bed during Hemodialysis Using the Rabbit Ear Chamber Technique

Leukocyte kinesis in the capillary vascular bed during hemodialysis (HD) was investigated to elucidate the mechanism of transient leukopenia. Leukocyte movement was observed microscopically during HD using the rabbit ear chamber (REC) technique, which permits visualization of the movement of blood corpuscles in capillaries. Blood was drawn from the femoral artery and returned into the auricular and/or carotid artery so that the blood passing through the hollow fiber artificial kidney (HFAK) flowed into capillaries in the REC. Leukocyte counts of blood samples taken from the afferent and efferent limbs of the HD circuit, the right jugular vein and the right atrium were determined consecutively during HD. The difference in the leukocyte count was observed between the afferent and efferent limbs for the first 15 minutes and thereafter between the efferent limb and the jugular vein. The “transpulmonary” difference in the leukocyte count was not noticed throughout HD. Between 15 and 90 minutes after the start of HD, scarcely any circulating leukocytes were found in capillaries in the REC and some leukocytes were attached to the endothelial surface. Thereafter circulating leukocytes were seen again and detachment of leukocytes from the endothelial surface was observed. No leukocyte aggregation or embolization of aggregating leukocytes was noticed. This evidence suggests that leukopenia may be attributed to the transient shift of leukocytes to the marginal pool of the vessel lumen and this process may not be specific for the pulmonary vasculature, but may occur in the first capillary bed into which the blood passing through the HFAK flows. The attachment of leukocytes to the surface membrane of the HFAK may contribute to the transient leukopenia especially during the initial period of the HD.

Bis(stibahousene)

Strained hydrocarbons constitute one of the most prominent classes of organic compounds. Among them, bicyclo[2.1.0]pentene ("housene") derivatives represent a highly challenging and very attractive class. Although organic housenes have been known for more than five decades, there are still very few of them containing heavier main group elements. In this paper, we report on the two housene-type structures, novel monomeric stibahousene and dimeric bis(stibahousene). The bonding natures of both compounds were approached from both experimental and computational directions to reveal their peculiar structural features.

The effect of bolus volume on laryngeal closure and UES opening in swallowing: Kinematic analysis using 320-row area detector CT study

This study investigated the effects of three different volumes of honey-thick liquid on the temporal characteristics of swallowing. Twenty-six healthy subjects (15 males, 11 females) underwent 320-row area detector CT scan while swallowing 3, 10 and 20 mL of honey-thick liquid barium. Three-dimensional images were created at 10 images/s. Kinematic events involving six structures (velopharynx, hyoid bone, epiglottis, laryngeal vestibule (LV), true vocal cords (TVC), upper esophageal sphincter (UES)) and timing of bolus movement were timed using frame by frame analysis. The overall sequence of events did not differ across three volumes; however, increasing bolus volume significantly changed the onset and termination of events. The bolus head reached to pharynx and esophagus earlier and the duration of bolus passing through UES was significantly longer in 10 and 20 mL compared to 3 mL (P < .05). Consequently, the onset of UES opening was significantly earlier with increased volume (P < .05). LV and TVC closure occurred later in 20 mL compared to 3 mL (P < .05). These changes in motion of pharynx and larynx appeared to promote swallow safety by preventing aspiration, suggesting that anatomical structure movements adapt in response to bolus volume. Our findings also suggest that the pharyngeal swallow behaviours may be modified by afferents in the oral cavity. The three-dimensional visualization and quantitative measurements provided by 320-ADCT provide essential benchmarks for understanding swallowing, both normal and abnormal.

Clinical Courses of Graft Failure Caused by Chronic Allograft Dysfunction in Kidney Transplantation

BACKGROUND

Chronic allograft dysfunction (CAD) is a main cause of graft failure in kidney transplantation.

METHODS

We retrospectively analyzed 279 kidney transplant recipients who survived with a functioning graft for at least 2 years. CAD was defined as chronic graft deterioration, excluding other specific causes. We defined the pattern of decline in estimated glomerular filtration rate (eGFR), as follows: (1) "plateau" was defined as decline in eGFR ≤2 mL/min/1.73 m²/year; "long plateaus" were those lasting more than 5 years; (2) "rapid decline" was a decrease in eGFR ≥20 mL/min/1.73 m²/year. Patients diagnosed with CAD were categorized according to the occurrence of rapid decline and/or long plateau as follows: group 1, neither rapid decline nor long plateau; group 2, rapid decline only; group 3, long plateau only; and group 4, both rapid decline and long plateau.

RESULTS

From a total of 81 graft losses, 51 (63%) failed because of CAD, with a median of 9.4 years. Sixteen patients belonged to group 1, 14 to group 2, 12 to group 3, and nine to group 4. Mean graft survival times in the four groups were 7.7 ± 1.1, 6.1 ± 3.1, 16.2 ± 2.5, and 10.8 ± 3.6 years, respectively (P < .001). There were significant differences among groups in donor age, year of transplantation, mean eGFR at baseline, and acute rejection rate after transplantation.

CONCLUSIONS

The results indicate that this cohort of kidney transplant recipients who had CAD comprised subgroups with different clinical courses.

Role of mitogen-activated protein kinase pathways in migration of gingival epithelial cells in response to stimulation by cigarette smoke condensate and infection by Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

Previous studies have shown that cigarette smoke (CS) and periodontal pathogens could alter wound healing responses of gingival epithelial cells. To elucidate molecular mechanisms leading to these epithelial changes, we studied the signaling pathway involved in the modulation of cell migration by CS condensate (CSC) and the infection by a prominent periodontal pathogen, Porphyromonas gingivalis.

MATERIAL AND METHODS

Human gingival epithelial cells (Ca9-22) were treated with CSC or vehicle control for 24 h. Activation of mitogen-activated protein kinases (MAPK) in cells with or without infection by P. gingivalis was assessed by polymerase chain reaction array and immunoblotting using phospho-specific antibodies. Cell migration was assessed using in vitro wound closure model, and specific pharmacologic inhibitors of MAPK pathways were used to characterize further the extent of involvement of the MAPK pathways.

RESULTS

Polymerase chain reaction array showed that gene expression of several members of the MAPK, particularly p38 and JNK, was upregulated more than twofold in Ca9-22 cells stimulated with 10 μg/mL CSC. Coincubation with P. gingivalis induced a different pattern of gene expression for MAPK pathways, but it did not suppress the MAPK-related genes upregulated by CSC. A significant phosphorylation of ERK1/2 and p38 was observed in cells stimulated with 10 μg/mL CSC (p < 0.05), whereas coincubation with a higher concentration of CSC (250 μg/mL) evoked no such activation. P. gingivalis infection resulted in a tendency to reduce the phosphorylation of ERK1/2 and p38, which had been enhanced by stimulation with 10 μg/mL CSC. Incubation with ERK1/2 and p38 inhibitors significantly reduced the wound closure of CSC-stimulated cells, by approximately 43% and 46%, respectively (p < 0.05).

CONCLUSION

CSC exerts effects on the migration of human gingival epithelial cells through the activation of the MAPK ERK1/2 and p38 signaling pathways. P. gingivalis infection attenuates the CSC-induced migration at least partly by suppressing the phosphorylation of ERK1/2 and p38, but other pathways are likely to be involved in this modulatory process.

Body size evolution of a shell-brooding cichlid fish from Lake Tanganyika

The substrate-brooding cichlid fish Telmatochromis temporalis in Lake Tanganyika demonstrates a simple example of ecological speciation between normal and dwarf morphs through divergent natural selection on body size. The dwarf morph most likely evolved from the ancestral normal morph; therefore, elucidating the evolution of its small body size is a key to understanding this ecological speciation event. Previous studies suggest that the small body size of the dwarf morph is an adaptation to the use of empty snail shells as shelters (males) and spawning sites (females), but this idea has not been fully evaluated. Combining original and previously published information, this study compared likelihood values to determine the primary factor that would be responsible for regulating the body size of the dwarf morph. Male body size is most likely regulated by the ability to turn within shells, which may influence the predation avoidance of adult fish. Females are smaller than males, and their body size is most likely regulated by the ability to lay eggs in the small spaces within shells close to the shell apices where predation risk on eggs is lower. This study provides new evidence supporting the hypothesis that different natural selection factors affected body size of the different sexes of the dwarf morph, which has not been reported in other animal species.

Cigarette smoke condensate modulates migration of human gingival epithelial cells and their interactions with Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

Epithelial cells are recognized as the first line of defense against bacterial infection and environmental harmful stimuli such as cigarette smoke (CS). Although previous studies explored the effects of nicotine on host cells, mechanisms by which CS affects cellular functions remain uncertain. The present study investigated the effects of CS condensate (CSC) on in vitro wound closure of gingival epithelial cells and their potential interactions with a major periodontal pathogen, Porphyromonas gingivalis.

MATERIAL AND METHODS

Human gingival epithelial cells (Ca9-22) were treated with CSC for 24 h. Cell proliferation was determined using a WST-1 assay. Cell migration was assessed using a wound closure model. The expression of integrins was analyzed by confocal scanning laser microscopy and real-time PCR. Intracellular invasion of P. gingivalis was evaluated by confocal scanning laser microscopy and an antibiotic protection assay.

RESULTS

Low concentrations (1-10 μg/mL) of CSC showed no significant effect on cell proliferation. CSC demonstrated dual effects on epithelial wound closure of Ca9-22 cells: high concentrations (i.e. 250 μg/mL) significantly inhibited the wound closure whereas low concentrations (i.e. 10 μg/mL) promoted it (p < 0.01). CSC induced distinct changes in cytoskeleton. When CSC-exposed cells were infected with P. gingivalis for 2 h, a significant inhibition of wound closure was observed concurrent with a decrease in integrin α3 expression near the wound area. A significantly increased P. gingivalis invasion into Ca9-22 was observed when exposed to low concentrations of CSC.

CONCLUSION

Low concentrations of CSC increased invasion of human gingival epithelial cells by P. gingivalis and induced changes in cytoskeleton and integrin expression, thereby modulating the cell migration.

Control of parathyroid hormone hydrolysis by the kidney

In order to assess the role of the kidney in controlling the degradation, fate, half-life, and consequently the functional level of the parathyroid hormone in vivo, highly purified bovine parathyroid hormone (bPTH 1-84) and synthetic N-terminal peptide of the bovine parathyroid hormone (bPTH 1-34) were iodinated and their hydrolysis by the kidney and liver tissue of rats were measured under various levels of parathyroid function and calcium metabolism. While the hydrolysis of bPTH 1-84 did not change significantly in response to acute change of serum parathyroid hormone in response to injections of EDTA, phosphate, and calcium or after parathyroidectomy, less bPTH 1-34 was hydrolyzed 60 min after injection of EDTA or phosphate along with the rise of serum PTH than in the controls. No significant change was found in the hydrolysis of bPTH 1-34 after calcium infusion or parathyroidectomy with a consequent fall of serum parathyroid hormone. Increase of calcium ions in the incubation medium in vitro resulted in a more pronounced increase of bPTH 1-34 hydrolysis than that of bPTH 1-84. Hydrolysis of the N-terminal portion of parathyroid hormone probably plays a more important role in the acute control of the functional level of the parathyroid hormone than the hydrolysis of the whole molecule.