Molecular conformation-activity relationship of decamethonium congeners

BACKGROUND

Of the polymethylene bismethonium congeners (C5-C12 and C18), decamethonium (C10) is the most potent neuromuscular blocking agent. We tested the hypothesis that these congeners act as straight molecules and will not bend easily in spite of the flexible connecting chain between the methonium heads. For congeners higher than C10, we also hypothesized that the relative difficulty with which the molecules to bend to conform to the interonium distance of C10 proportionately reduces their neuromuscular blocking potency.

METHODS

Each congener was modelled and subjected to computer searches for representative low-energy molecular conformers. The conformation-potency relationship of the congeners was examined.

RESULTS

For all congeners, we found that the lowest energy conformer (the 'global minimum') has a straight-chain conformation. Reduction of the interonium distance (by bending) incurs a steep energy penalty linearly related to the distance reduced. The global minimum of C10 has an interonium distance of 14.03 A and a total molecular length of 20.10 A. For other congeners, the interonium distance differential from that of C10 and the energy penalty required to conform to the interonium distance of C10 (where applicable) correlate with the reported logarithmic (mmol kg(-1)) dose requirement for neuromuscular block.

CONCLUSIONS

The C10 congeners strongly prefer a straight conformation. Their molecular length and resistance to bending is key to their neuromuscular blocking potency. A molecular length of approximately 20 A should best fit the space available to neuromuscular blocking agents between the two receptive sites of the endplate acetylcholine receptor.

Protein glycation: creation of catalytic sites for free radical generation

In a glycation reaction, alpha-dicarbonyl compounds such as deoxyglucosone, methylglyoxal, and glyoxal are more reactive than the parent sugars with respect to their ability to react with amino groups of proteins to form inter- and intramolecular cross-links of proteins, stable end products called advanced Maillard products or advanced end products (AGEs). The AGEs, which are irreversibly formed, accumulate with aging, atherosclerosis, and diabetes mellitus, and are especially associated with long-lived proteins such as collagens, lens crystallins, and nerve proteins. It was suggested that the formation of AGEs not only modifies protein properites but also induces biological damage in vivo. In this report, we summerize results obtained from our studies for (1) identifying the structure of the cross-linked radical species formed in the model system-the reaction between alpha-dicarbonyl methylglyoxal with amino acids, and (2) the reactivity of the radical center of the protein created by the similar reaction. These results indicate that glycation of protein generates active centers for catalyzing one-electron oxidation-reduction reactions. This active center, which exhibits enzyme-like character, is suggested to be the cross-linked Schiff-based radical cation of the protein. It mimics the characteristics of the metal-catalyzed oxidation system. These results together indicate that glycated proteins accumulated in vivo provide stable active sites for catalyzing the formation of free redicals.

Genetic antagonism between body weight and milk production in beef cattle

Korean cattle have an unusually short suckling period (4 mo) due to poor milking ability, and this is a hindrance to growth of calves. Therefore, Korean cattle breeders have shown interest in genetic improvement of milking ability. In this study, body weight (birth weight, weaning weight, and yearling weight) and five daily milk yields by period in Korean cattle (Hanwoo) were analyzed using a two-trait sire and maternal grandsire mixed model. The milk yields used were actually measured at sequential intervals from 1 to 4 mo after calving. Posterior means of the parameters were estimated using Gibbs sampling. Heritability estimates (0.25 to 0.26) for daily milk yield at weaning were larger than those with other periods. Genetic impact on daily milk yield, especially at weaning, was emphasized in order to lengthen the suckling period of Korean cattle. Genetic correlation estimates between BW and daily milk yield were all negative (-0.08 to -0.16 for birth weight, -0.04 to -0.21 for weaning weight, and -0.12 to -0.19 for yearling weight), whereas environmental correlation estimates were all positive (0.20 to 0.39 for birth weight, 0.34 to 0.51 for weaning weight, and 0.30 to 0.45 for yearling weight). The negative estimates of genetic correlation between weight and milk yield implied genetic antagonism between direct and maternal effects for weaning weight of beef cattle.

Non-bronchoscopic bronchoalveolar lavage in the microbiological diagnosis of pneumonia in mechanically ventilated patients

A prospective study comparing standardized non-bronchoscopic bronchoalveolar lavage (sNB-BAL) and non-specific endotracheal aspirate (NsETA) in the microbiological diagnosis of pneumonia in mechanically ventilated patients is described. One hundred episodes in 82 mechanically ventilated patients with or without radiological and clinical diagnostic criteria of pneumonia were studied. NsETA and sNB-BAL was performed on the day of study. Fifty-one patients had pneumonia (21 ventilator-associated, 12 hospital-acquired, 18 community-acquired) and 49 had no pneumonia as defined by widely accepted clinico-radiological criteria. The sNB-BAL was found to be significantly more specific (0. 73) compared to NsETA (0.35) for the microbiological diagnosis of pneumonia. Colonization rates with NsETA were significantly higher compared to sNB-BAL (P value <0.0001). No patient had complications attributable to the sNB-BAL procedure. We conlude that sNB-BAL is a safe, effective, sensitive, specific and inexpensive procedure for the serial evaluation of pneumonia in mechanically ventilated patients.

Thrombospondin-1, vascular endothelial growth factor expression and their relationship with p53 status in prostate cancer and benign prostatic hyperplasia

OBJECTIVE

To evaluate the expression of thrombospondin-1 (TSP-1, a potent inhibitor of angiogenesis) and vascular endothelial growth factor (VEGF, an important angiogenic factor in solid tumours) in prostate cancer, and their relationship with p53 status.

PATIENTS AND METHODS

Using immunohistochemistry, the expression of VEGF, TSP-1 and p53 was assessed in 82 archival tissue specimens from 23 patients with benign prostatic hyperplasia (BPH), 22 with localized prostate cancer and 37 with metastatic prostate cancer. Seven of the last group had received androgen deprivation therapy. The relationship between the expression of VEGF, TSP-1 and p53 status was also evaluated with tumour grade and stage in patients with prostate cancer.

RESULTS

The seven patients receiving hormonal treatment were excluded from the analysis because androgen deprivation significantly increased TSP-1 and decreased VEGF expression (both P < 0.01). Immunohistochemical analysis showed significantly higher VEGF and significantly lower TSP-1 expression (both P < 0.01) in prostate cancer than in BPH tissues. There was also significantly higher VEGF and significantly lower TSP-1 expression (both P < 0.05) in tissues from metastatic than localized prostate cancer. There was no significant correlation between VEGF or TSP-1 expression and Gleason score, but a significant inverse correlation between TSP-1 and VEGF expression. There was a significant association between VEGF expression and p53 status (P < 0.05), but TSP-1 expression was not associated with p53 status.

CONCLUSIONS

Angiogenic factors, including VEGF and TSP-1, might be important in the development and progression of prostate cancer. These changes seem to be influenced by p53 status. Identifying the angiogenic factors involved in prostate cancer might lead to the development of diagnostic or therapeutic strategies based on anti-angiogenesis.

A noninvasive estimation of hypernasality using a linear predictive model

The pronunciation of a speaker with a defective soft palate is marked by hypernasality and an operation may be necessary to repair the defective soft palate to reduce this hypernasality. An assessment of hypernasality is necessary to quantify the effect of the surgery. The current clinical methods for assessing hypernasality are uncomfortable or require expensive equipment. In this paper, a new quantitative method is proposed to estimate hypernasality. This method requires only a microphone and a personal computer equipped with a sound card. Zeros in the frequency response of the vocal tract system are one of the major characteristics of hypernasality. The proposed method made use of the fact that a linear predictive model with a typical order for the human vocal tract system is not accurate when the vocal tract system has zeros in its frequency response. Hypernasality was estimated by comparing the distance between the sequences of linear predictive cepstrum of low- and high-order linear predictive models. The proposed method provides a better correlation (0.58) with nasalance measured by a nasometer than Teager method (0.44) for all the data. Furthermore, the proposed method showed higher correlation of 0.84 than 0.71 of the Teager method for data with a nasalance higher than 35%. Since the proposed method needs only digitized speech data, it is much less invasive and provides an easy and cost-effective evaluation of hypernasality.

Infection-mediated early-onset periodontal disease in P/E-selectin-deficient mice

BACKGROUND

Retrospective and correlation studies suggest that early-onset periodontal disease may be due to a deficiency in phagocyte function, a pathogenic oral biofilm, and/or dysregulated gingival cytokine expression. Increased susceptibility to periodontal disease is therefore thought to result from multiple risk factors.

METHODS

We tested this hypothesis prospectively using P/E-selectin adhesion molecule deficient mice that mimic the human syndrome leukocyte adhesion deficiency II.

RESULTS

Our studies demonstrate that, in comparison to wild type animals, P/E-/- mice exhibit: spontaneous, early onset alveolar bone loss which is significant by 6 weeks of age; a 10-fold elevation in bacterial colonization of their oral cavities; and elevated gingival tissue levels of the bone resorptive cytokine IL-1alpha. Alveolar bone loss is completely prevented by prophylactic antibiotic therapy.

CONCLUSIONS

These experiments provide the first prospective evidence for the multiple risk factor hypothesis of periodontal disease, and validate the first animal model for early onset periodontitis in which both the microbiota and host response can be systematically manipulated. P/E-/- animals should be useful in testing the virulence of putative periodontal pathogens, in determining the role of host resistance factors in periodontitis, in exploring the proposed relationship(s) between infection mediated alveolar bone loss and systemic health disorders, and exploring their genetic relationships.

Modulation of Chelidonii herba on GABA activated chloride current in rat PAG neurons

Modulation of Chelidonii herba on gamma-aminobutyric acid (GABA) activated chloride current in the acutely dissociated periaqueductal gray (PAG) neuron was studied by nystatin-perforated patch-clamp technique. High concentrations of Chelidonii herba elicited ion current, that was blocked by bicuculline. Low concentrations reduced the GABA activated current in PAG. Two types of inhibitory action of Chelidonii herba on GABA activated current have been implicated in PAG. One is the inhibitory action of Chelidonii herba on GABA was abolished by naltrexone and the other is that of Chelidonii herba was potentiated by naltrexone. In addition, all of two types of action of Chelidonii herba are linked to pertussis toxin-sensitive GTP-binding proteins. These results suggest that the inhibitory modulation of Chelidonii herba on GABA activated current via G-proteins in PAG neuron is an important analgesic mechanism.

Posttranslational mechanisms regulate the mammalian circadian clock

We have examined posttranslational regulation of clock proteins in mouse liver in vivo. The mouse PERIOD proteins (mPER1 and mPER2), CLOCK, and BMAL1 undergo robust circadian changes in phosphorylation. These proteins, the cryptochromes (mCRY1 and mCRY2), and casein kinase I epsilon (CKIepsilon) form multimeric complexes that are bound to DNA during negative transcriptional feedback. CLOCK:BMAL1 heterodimers remain bound to DNA over the circadian cycle. The temporal increase in mPER abundance controls the negative feedback interactions. Analysis of clock proteins in mCRY-deficient mice shows that the mCRYs are necessary for stabilizing phosphorylated mPER2 and for the nuclear accumulation of mPER1, mPER2, and CKIepsilon. We also provide in vivo evidence that casein kinase I delta is a second clock relevant kinase.

gem-Diacetates as carbonyl surrogates for asymmetric synthesis. Total syntheses of sphingofungins E and F

The equivalent of an asymmetric addition to a carbonyl group with a stabilized anion is accomplished by discriminating between the enantiotopic C-O single bonds of a gem-diacetate. In this way, enantioselective total syntheses of two antifugal agents, sphingofungins E and F, have been accomplished. The synthetic strategy is based on a series of catalytic processes whereby all of the chiral centers are created with high stereoselectivities. The first two stereocenters are introduced by an asymmetric allylic alkylation reaction of gem-diacetate 9 with azlactone 10. The complex of Pd(0) and ligand 14 efficiently catalyzes this key reaction, which differentiates both the enantiotopic leaving groups of a gem-diacetate and enantiotopic faces of the enolate of an azlactone in high enantiomeric excess and diastereomeric excess. From these two stereocenters, the configurations of the remaining two centers are set by a diastereoselective Os(VIII)-catalyzed dihydroxylation reaction with excellent stereocontrol. The trans-alkene is established by Cr(II)-mediated olefination, and a subsequent B-alkyl Suzuki coupling reaction conjoins the polar head unit and the nonpolar, 13-carbon lipid tail. The efficiency of our strategy is illustrated by the completion of syntheses of sphingofungins F and E in 15 and 17 steps, and in 17% and 5% overall yields, respectively.

Enhanced IL-18 expression in common skin tumors

Interleukin-18 (IL-18) has been found to have multiple effects upon various cells involved in inflammatory response. Recently we reported that B16 murine melanoma cells are able to produce IL-18, which is involved in the regulation of intracellular reactive oxygen intermediates (ROI) and Fas-ligand expression, indicating that IL-18 plays key role in the tumor activity of melanoma. In this study, we investigated the pattern of IL-18 expression in the human system. IL-18 production was tested by enzyme linked immunosorbent assay (ELISA) assay in various tumor cell lines, including Raji (Burkitt's lymphoma), IM-9 (B lymphoblast), Jurkat (acute T cell leukemia), SK-MES-1 (squamous cell carcinoma (SCC) cell line), SK-MEL-2, G-361, DM-4, and DX-3 (melanoma cell lines). ELISA tests showed that IL-18 was highly expressed in malignant skin tumors such as SK-MES-1, SK-MEL-2, G-361, DM-4, and DX-3 cell lines, thus suggesting that IL-18 production may be associated with the malignancy of skin tumors. Here, we report that enhanced IL-18 expression is positively correlated with malignant skin tumors such as SCC and melanoma, suggesting the importance role of IL-18 in malignancy of skin tumors. Taken together, expression of IL-18 by tumor cells in human skin tissue may provide an important clue to understand the pathogenesis of malignant skin tumors.

A new naphthoquinone from Pyrola japonica

A new naphthoquinone, 5,8-dihydro-2,7-dimethyl-[1,4]naphthoquinone (1), which was named 5,8-dihydrochimaphilin, isolated from an ethyl acetate soluble fraction from the root of Pyrola japonica, together with chimaphilin (2). Compound 1 was transformed rapidly to 2 upon exposure to air by HPLC analysis. This fact supported that chimaphilin (2) may be an artifact from 1.

The disability profile of patients with schizophrenia in psychiatric hospital and community settings in Singapore

The disability profile of persons with schizophrenia in Singapore and how disability levels vary in patients cared for in the community and in the long-stay wards of a state mental hospital were studied using the Life Skills Profile (LSP). The inter-rater reliability of the LSP assessed by the intraclass correlation coefficient (ICC), was lower than in the Australian studies. The test-retest ICCs for the total LSP score and the five subscale scores were satisfactory for the hospitalised subjects and for the community psychiatric nurse subjects, but generally poor for the community care facility subjects. The average ICCs were lower compared to the Australian study. Female hospitalised subjects but not male hospitalised subjects returned higher disability scores on all LSP scales compared to community subjects. This study provided some preliminary data on the usefulness and validity of the LSP in a multi-ethnic Asian setting like Singapore. If the LSP is used as a measure of disability in schizophrenia, it would appear that ratings should only be made by those who know the subject well, and that raters should be formally trained mental health professionals.

Non-veridical visual motion perception immediately after saccades

It is widely assumed that combining the eye movement vector with the motion vector of the retinal image is both sufficient and necessary for recovering the direction and speed of visual motion. Here, we report that execution of a saccadic (rapid) eye movement in the dark systematically biased subsequent perceptual judgment of the direction of visual motion in the direction opposite to the saccade. This non-veridical motion perception reached a maximum immediately after saccade offset and then decayed in approximately equal to 100 ms. These results suggest that the oculomotor signal interacts with central mechanisms related to motion and possibly form perception, as well as spatial vision, as documented with mislocalization of visual objects at the time of saccades.

Impaired nonhomologous end-joining provokes soft tissue sarcomas harboring chromosomal translocations, amplifications, and deletions

Although nonhomologous end-joining (NHEJ) deficiency has been shown to accelerate lymphoma formation in mice, its role in suppressing tumors in cells that do not undergo V(D)J recombination is unclear. Utilizing a tumor-prone mouse strain (ink4a/arf(-/-)), we examined the impact of haploinsufficiency of a NHEJ component, DNA ligase IV (Lig4), on murine tumorigenesis. We demonstrate that lig4 heterozygosity promotes the development of soft-tissue sarcomas that possess clonal amplifications, deletions, and translocations. That these genomic alterations are relevant in tumorigenesis is supported by the finding of frequent mdm2 amplification, a known oncogene in human sarcoma. Together, these findings support the view that loss of a single lig4 allele results in NHEJ activity being sufficiently reduced to engender chromosomal aberrations that drive non-lymphoid tumorigenesis.

Blockage of complement regulators in the conjunctiva and within the eye leads to massive inflammation and iritis

The open environment of the eye is continuously subject to an influx of foreign agents that can activate complement. Decay-accelerating factor (DAF), membrane cofactor protein (MCP) and CD59 are regulators that protect self-cells from autologous complement activation on their surfaces. They are expressed in the eye at unusually high levels but their physiological importance in this site is unstudied. In the rat, a structural analogue termed 5I2 antigen (5I2 Ag) has actions overlapping DAF and MCP. In this investigation, we injected F(ab')2 fragments of 5I2 mAb into the conjunctiva and aqueous humor, in the latter case with and without concomitant blockage of CD59. Massive neutrophilic infiltration of the stroma and iris resulted upon blocking 5I2 Ag activity. Frank necrosis of the iris occurred upon concomitant intraocular blockage of CD59. C3b was identified immunohistochemically, and minimal effects were seen in complement-depleted animals and in those treated with non-relevant antibody. The finding that blockage of 5I2 Ag function in periocular tissues and within the eye causes intense conjunctival inflammation and iritis demonstrates the importance of intrinsic complement regulators in protecting ocular tissues from spontaneous or bystander attack by autologous complement.

Multicolor fluorescence in situ hybridization in clinical cytogenetic diagnostics

Multicolor fluorescence in situ hybridization is a technology that has vastly expanded the diagnostic repertoire of the clinical cytogenetics laboratory. The limitations of conventional chromosome banding analysis can often be overcome by the high sensitivity and specificity of multicolor fluorescence in situ hybridization tests. This article reviews the latest multicolor fluorescence in situ hybridization tests (including multiplex fluorescence in situ hybridization, spectral karyotyping, cross-species color banding, and comparative genomic hybridization) that are currently limited to a few select clinical cytogenetic laboratories, but may soon have more dominant roles in clinical cytogenetic practice.