[Analysis of clinical characteristics and risk factors of death in critical burn patients complicated with invasive fungal infection]

Objective: To investigate the clinical characteristics and risk factors of critical burn patients complicated with invasive fungal infection. Methods: A retrospective case series study was conducted. From January 2017 to December 2022, 88 critical burn patients combined with invasive fungal infection who met the inclusion criteria were admitted to Zhengzhou First People's Hospital, including 61 males and 27 females, aged 26-74 years. Data on invasive fungal infection sites and the detection of pathogens in patients were recorded. According to the survival outcome within 28 days after admission, the patients were divided into survival group (63 cases) and death group (25 cases). The following data of patients were compared between the two groups, including the basic data and injuries of patients at admission such as age, sex, body weight, total burn area, combination of inhalation injury, combination of hypertension and diabetes, acute physiology and chronic health status evaluation Ⅱ (APACHE Ⅱ) score, and admission time after burns, the levels of blood biochemical indexes within 24 h after admission such as white blood cell count, platelet count, red blood cell count, monocyte count, neutrophil count, lymphocyte count, alanine transaminase, aspartate transaminase, glucose, creatinine, urea nitrogen, D-dimer, galactomannan (GM), 1,3-β-D glucan, and creatine kinase, the application of invasive procedures and vasoactive drugs during the treatment such as continuous renal replacement therapy, ventilator-assisted breathing, tracheotomy, deep vein catheterization, skin grafting >2 times, the levels of infection indicators on post admission day (PAD) 1, 3, 7, and 14 including C-reactive protein (CRP), procalcitonin, lactic acid, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and the detection of pathogens in the process of treatment. Data were statistically analyzed with independent sample t test, analysis of variance for repeated measurement, chi-square test, Mann-Whitney U test, and Bonferroni correction. Multivariate logistic regression analysis was performed to screen the independent risk factors that affected death of critical burn patients complicated with invasive fungal infection. Results: The main sites of invasive fungal infection were the wounds (67 cases) and blood stream (46 cases), with Candida fungi (58 strains) as the main strain for fungi infection, and there were a total of 30 cases of infection with mixed pathogenic bacteria. Compared with those in survival group, the APACHE Ⅱ score, proportions of combination with inhalation injury and hypertension of patients in death group were significantly increased (t=2.11, with χ2 values of 6.26 and 9.48, respectively, P<0.05), while the other basic data and injury condition had no significant changes (P>0.05). Compared with those in survival group, the levels of D-dimer, GM, and 1,3-β-D glucan of patients in death group were significantly increased within 24 h after admission (with t values of 2.42, 2.05, and 2.21, respectively, P<0.05), while the other blood biochemical indexes within 24 h after admission, as well as the proportions of applying invasive procedures and application of vasoactive drugs during the treatment process were not significantly changed (P>0.05). The levels of infection indicators of patients on PAD 1 and 3 were similar between the two groups (P>0.05). The procalcitonin level on PAD 7 and the levels of CRP, procalcitonin, lactic acid, IL-6, and TNF-α on PAD 14, as well as the proportion of infection with mixed pathogenic bacteria of patients in death group were significantly higher than those in survival group (with t values of 4.69, 3.89, 6.70, 6.14, 4.65, and 3.26, respectively, χ2=12.67, P<0.05). Multivariate logistic regression analysis showed that combination with inhalation injury, combination with hypertension, and infection with mixed pathogenic bacteria were independent risk factors for death of critical burn patients complicated with invasive fungal infection (with odds ratios of 5.98, 4.67, and 6.19, respectively, 95% confidence intervals of 1.42-15.39, 1.41-25.28, and 1.86-20.58, respectively, P<0.05). Conclusions: The main sites of infection in critical burn patients complicated with invasive fungal infection are the wounds and blood stream, with Candida fungi as the main strain for fungi infection, and a large proportion of infection with mixed pathogenic bacteria. The combined inhalation injury, combined hypertension, and infection with mixed pathogenic bacteria are the independent risk factors for the death of those patients.

Role-play of real patients improves the clinical performance of medical students

BACKGROUND

This study aimed to evaluate whether the role-play (RP) of real patients by medical students as part of interactive clinical reasoning training can improve medical students' clinical performance.

METHODS

A total of 26 medical students volunteered to portray real patients within this program and were treated as the RP group while the other 72 students as the non-RP group. In the interactive morning meeting, the medical students practiced how to approach the RP student as if they were encountering a real patient. All students were evaluated by mini-clinical evaluation exercises (mini-CEX) before and after this training program.

RESULTS

We found that all students had an increased total mini-CEX score after 4-week training, especially for interviewing skills. Notably, after training, the RP students had significantly elevated total mini-CEX scores (51.23 ± 1.06 vs 53.12 ± 1.11, p = 0.028), and for counselling (7.15 ± 0.14 vs 7.54 ± 0.18, p = 0.015) and overall clinical competence (7.27 ± 0.15 vs 7.65 ± 0.16, p = 0.030). In contrast, the non-RP students had lower scores compared with the RP group, as revealed by both the pre- and post-training tests. Moreover, their mini-CEX scores were not improved after training.

CONCLUSION

Medical students who were motivated to RP real patients had better performance scores than those who did not. In addition, RP can enhance their counselling skills and clinical competences.

Clinical usefulness of bronchoalveolar lavage in patients with interstitial lung diseases: a pilot study

Background

Bronchoalveolar lavage (BAL) is a useful tool in the diagnostic work-up of patients with interstitial lung diseases (ILDs). In this prospective study, we investigated the clinical usefulness of BAL in patients with ILD radiographically.

Methods

The enrolled patients were classified into outpatient department (OPD), and inpatients groups who was admitted to general ward (GW) or intensive care unit (ICU) groups based on the time when BAL done. The clinical usefulness of BAL was defined as a new diagnosis established and/or treatment significantly changed. The clinical usefulness of BAL among the three groups of patients and the patients divided by underlying diseases was compared using the χ² test with or without Fisher’s exact test.

Results

Among our 184 patients, there were 37 in OPD group, 86 in GW group and 61 in ICU group. The final diagnoses were infectious in 23, non-infectious in 102, mixed etiologies in 19, and non-diagnostic in 40 patients. The diagnostic yields (revised diagnosis after BAL) of BAL among ICU patients, GW patients and OPD patients were 60.6%, 69.7% and 21.6%, respectively (P<0.001), and was 57.1% in total patients. The diagnostic yields of BAL among patients with cancer, organ transplantation and collagen vascular disease were statistically different (P=0.009).

Conclusions

BAL is of use in establishing a diagnosis of ILD and is mandatary especially in the admitted patients with ILD because diagnostic yield was relatively higher in admitted patients than in OPD patients. In addition, BAL should be done more early in the admitted patients with malignancy, stem cell and/or organ transplantation and collagen vascular disease especially when they showed poor response to initial medications.

Abstract P5-12-01: A novel gene expression signature prognostic for both locoregional and distant failure and predictive for adjuvant radiotherapy

Background: Most patients with early stage breast cancer (BC) are treated with adjuvant radiotherapy (RT) following breast conserving surgery (BCS) to prevent locoregional recurrences (LRR). No predictive tools are currently available to select patients for RT, resulting in considerable over- and under treatment. We aimed to create and validate a gene expression-based classifier to prognosticate for LRR and to stratify patients for treatment with RT.

Patients and methods: A 27-gene expression signature was developed using three publicly available early stage BC gene expression datasets where patients were treated with RT and had detailed local recurrence information. The largest of the datasets was used to train the signature, and the other two datasets were used for signature refinement. As age was the strongest clinical factor for the endpoint in the training dataset, it was included in the model, resulting in a final clinical-genomic classifier of 27 genes and age. The classifier was locked before external validation in the SweBCG91-RT trial. This phase III clinical trial included primary tumors from 765 patients and for which gene expression data was available. The trial randomized node-negative BC patients to +/- RT following BCS, with sparse use of adjuvant systemic treatment (9%) and a median follow-up of 14.0 years for LRR in patients free from event. The classifier was validated using Cox regression with LRR as the primary endpoint, and hazard ratios (HRs) were calculated using the raw continuous classifier score (range: 0.5 to 2.5).

Results: The novel classifier was highly prognostic for LRR in SweBCG91-RT patients treated with RT (HR=7.5[3.3-16.9], p&lt;0.001), and remained prognostic in multivariate analysis (MVA) that included systemic treatment, subtype and grade (HR=7.2[3.1-16.4], p&lt;0.001). To a lesser extent, the classifier was also prognostic for LRR in patients not treated with RT (HR=1.9[1.0-3.5], p=0.03; MVA HR=1.9[1.0-3.3], p=0.05). Patients at high risk of LRR had a smaller effect of RT, and the treatment predictive potential was confirmed by testing for interaction (pinteraction=0.008). In patients treated with RT, age and the genomic component of the model were both prognostic for LRR (p&lt;0.01) as well as predictive for RT response (pinteraction&lt;0.05) and provided independent information (p&lt;0.01). The combined classifier has increased performance over its individual components (10-year AUC=0.72, 0.67, 0.65 for the classifier, age, and genomic component, respectively). While the novel signature was prognostic for metastasis (HR=4.3[2.3-7.8], p&lt;0.0001), calculated scores from previously published signatures to the metastasis endpoint, including the Oncotype-like score, were not prognostic for LRR.

Conclusions: This novel gene expression signature is highly prognostic for LRR, can identify patients at risk of LRR despite RT, and appears to be treatment predictive for adjuvant RT. Furthermore, the current signature is highly prognostic for metastasis. In contrast, calculated scores of previously published signatures modeled for the metastasis endpoint had inferior performance for LRR. These results underscore both the importance of signatures prognostic for LRR and the similarities in the biology of LRR and distant failure.

Citation Format: Sjöström M, Chang SL, Fishbane N, Davicioni E, Zhao SG, Hartman L, Holmberg E, Feng FY, Speers CW, Pierce LJ, Malmström P, Fernö M, Karlsson P. A novel gene expression signature prognostic for both locoregional and distant failure and predictive for adjuvant radiotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-01.

Dramatic band gap reduction incurred by dopant coordination rearrangement in Co-doped nanocrystals of CeO2

A dramatic band gap narrowing of 1.61 eV has been observed in Co-doped nanocrystals of CeO₂ (ceria), as a result of thermal annealing, without changing the ceria crystal structure and the Co concentration. As demonstrated by x-ray absorption fine structures, thermal annealing incurs an oxygen coordination rearrangement around Co atoms from an octahedral coordination to a square-planar coordination. First principle calculation using density functional theory reveals two stable oxygen coordination types surrounding Co, consistent with the experimental observation. The band gap values calculated for the two stable coordination types differ dramatically, reproducing the experimentally observed band gap narrowing. These prominent effects due to local structure rearrangement around dopant atoms can lead to unprecedented methods for band gap engineering in doped nanocrystal oxides.

Unconventional interplay between heterovalent dopant elements: Switch-and-modulator band-gap engineering in (Y, Co)-Codoped CeO2 nanocrystals

We report the experimental observation and theoretical explanation of an unconventional interplay between divalent Co and trivalent Y dopants, both of which incur oxygen vacancies in the CeO₂ host that has predominantly tetravalent Ce cations. The Co dopant atoms were experimentally found to act as a switch that turns on the dormant effect of Y-modulated band-gap reduction. As revealed by density functional theory (DFT) calculations with structures verified by synchrotron-radiation x-ray measurements, a Co 3d band that hybridizes with Ce 4f band was lowered due to reduced O 2p repulsion arising from oxygen vacancies incurred by Y doping and therefore gave rise to the observed band-gap narrowing effect. Such switch-and-modulator scheme for band-gap engineering in nanocrystal materials can lead to important applications in environmental protection and solar energy harvesting technologies.

Endothelial CXCR7 regulates breast cancer metastasis

Atypical chemokine receptor CXCR7 (ACKR3) functions as a scavenger receptor for chemokine CXCL12, a molecule that promotes multiple steps in tumor growth and metastasis in breast cancer and multiple other malignancies. While normal vascular endothelium expresses low levels of CXCR7, marked upregulation of CXCR7 occurs in tumor vasculature in breast cancer and other tumors. To investigate effects of endothelial CXCR7 in breast cancer, we conditionally deleted this receptor from vascular endothelium of adult mice, generating CXCR7^ΔEND/ΔEND animals. CXCR7^ΔEND/ΔEND mice appeared phenotypically normal, although these animals exhibited a modest 35 ± 3% increase in plasma CXCL12 as compared with control. Using two different syngeneic, orthotopic tumor implant models of breast cancer, we discovered that CXCR7^ΔEND/ΔEND mice had significantly greater local recurrence of cancer following resection, elevated numbers of circulating tumor cells, and more spontaneous metastases. CXCR7^ΔEND/ΔEND mice also showed greater experimental metastases following intracardiac injection of cancer cells. These results establish that endothelial CXCR7 limits breast cancer metastasis at multiple steps in the metastatic cascade, advancing understanding of CXCL12 pathways in tumor environments and informing ongoing drug development targeting CXCR7 in cancer.

Microfluidic source-sink model reveals effects of biophysically distinct CXCL12 isoforms in breast cancer chemotaxis

Chemokines critically regulate chemotaxis in normal and pathologic states, but there is limited understanding of how multicellular interactions generate gradients needed for cell migration. Previous studies of chemotaxis of CXCR4+ cells toward chemokine CXCL12 suggest the requirement of cells expressing scavenger receptor CXCR7 in a source-sink system. We leveraged an established microfluidic device to discover that chemotaxis of CXCR4 cells toward distinct isoforms of CXCL12 required CXCR7 scavenging only under conditions with higher than optimal levels of CXCL12. Chemotaxis toward CXCL12-β and -γ isoforms, which have greater binding to extracellular molecules and have been largely overlooked, was less dependent on CXCR7 than the more commonly studied CXCL12-α. Chemotaxis of CXCR4+ cells toward even low levels of CXCL12-γ and CXCL12-β still occurred during treatment with a FDA-approved inhibitor of CXCR4. We also detected CXCL12-γ only in breast cancers from patients with advanced disease. Physiological gradient formation within the device facilitated interrogation of key differences in chemotaxis among CXCL12 isoforms and suggests CXCL12-γ as a biomarker for metastatic cancer.

Instantaneous normal mode analysis of orientational motions in liquid water: local structural effects

We have investigated the effects of local structures on the orientational motions in liquid water in terms of the instantaneous normal mode (INM) analysis. The local structures of a molecule in liquid water are characterized by two different kinds of index: the asphericity parameter of its Voronoi polyhedron and the numbers of the H bonds donated and accepted by the molecule. According to the two kinds of index, the molecules in the simulated water are classified into subensembles, for which the rotational contributions to the INM spectrum are calculated. Our results indicate that by increasing the asphericity, the rotational contribution has a shift toward the high-frequency end in the real spectrum and a decrease in the fraction of the imaginary modes. Furthermore, we find that this shift essentially relies on the number of the donated H bonds of a molecule, but has almost nothing to do with that of the accepted H bonds. The local structural effects resulting from the geometry of water molecule are also discussed.

Development of Taenia asiatica cysticerci to infective stage and adult stage in Mongolian gerbils

The development of metacestodes and adult worms of Taenia asiatica in Mongolian gerbils (Meriones unguiculatus) were observed. Cysticerci were recovered from gerbils subcutaneously injected with hatched oncospheres. The recovery rate ranged from 0.1 to 3.2%. No cysticerci were recovered from the orally inoculated gerbils. The infectivity of the cysticerci recovered at 48 weeks post-infection was evaluated. Tapeworms were recovered on day 14 post-infection from the small intestine of 5 of 11 gerbils, with a recovery rate of 27% (6 worms recovered/22 worms inoculated). Three and four adult worms were recovered from two human volunteers who ingested five cysticerci after 4 months post-infection. In worms recovered from gerbils, segmentation and genital primordia in the posterior proglottids and hooklets in the residual rostellum were observed. The results indicate that gerbils can serve as an alternative intermediate host and that partial development of the adult worm stage occurs in gerbils.

Calculations of cellular microdosimetry parameters for alpha particles and electrons

The cellular microdosimetry parameters including the cellular S-value and the single-event specific energy distribution for alpha particles and electrons are important in radiation dosimetry and biology. These parameters may be used to determine the relative biological effectiveness of radiations in the boron neutron capture therapy. In the present work, such parameters were calculated for different source to target region combinations, i.e. cell surface, cytoplasm, nucleus and cell. Calculations were made using a semi-analytical model that simulated the emission of alpha particles or electrons by the Monte Carlo method and calculated the energy imparted to the target volume by the analytical method. Delta particle equilibrium and partial delta particle equilibrium were applied to alpha particles and electrons, respectively. Range-energy relations were employed to determine the incident and emerging energies of the primary particles. For electrons, the fraction in the energy loss resulting from the generation of bremsstrahlung and high-energy secondary electrons was estimated. The energy loss straggling of electrons entering and leaving a target volume was also estimated. Calculated cellular S-values were compared to corresponding data of the MIRD Committee. Calculated single-event specific energy distributions were also compared to results calculated using the Penelope code.

Mechanism for singular behavior in vibrational spectra of topologically disordered systems: short-range attractions

At low-enough fluid densities, we have found some naive singular behavior, like the van Hove singularities in the phonon spectra of lattices, appearing in the instantaneous normal mode spectra of the Lennard-Jones (LJ) 2n-n fluids, which serve as a prototype of topologically disordered systems. The singular behavior cannot be predicted by the mean-field theory, but interpreted by the perturbed binary modes of some special pairs, called the mutual nearest neighbor pairs, at separations corresponding to the extreme binary frequencies, which are solely determined by the attractive part of the LJ 2n-n pair potential. By reducing the range of attraction in the pair potential under the conditions of the same particle diameter and well depth, the tendency for the appearance of the singular behavior shifts to higher fluid densities. From this study, we conclude that pair potential with a short-range attraction can be a mechanism to produce a counterpart of the van Hove singularity in the vibrational spectra of disordered systems without a reference lattice.

Development of Taenia saginata asiatica metacestodes in SCID mice and its infectivity in human and alternative definitive hosts

Development of Taenia saginata asiatica metacestodes in SCID mice, and its infectivity in humans, golden hamsters, and Mongolian gerbils as alternative definitive hosts, were investigated. Cysticerci were recovered from SCID mice that were subcutaneously injected with hatched oncospheres of T. s. asiatica. The morphological changes of metacestodes were observed. The recovered cysticerci were fed to gerbils, hamsters and humans, to check for their infectivity. Tapeworms were recovered from gerbils and hamsters fed with 20 to 45 week-old cysticerci, and proglottids excretions were observed in human volunteers fed with 45 week-old cysticerci. However, no tapeworms were recovered from gerbils fed with 10 week-old cysticerci. Our results suggest that T. s. asiatica oncospheres needed more than 20 weeks to develop to maturity in SCID mice to be infective to both their natural and alternative definitive hosts.

Characteristics of the new THOR epithermal neutron beam for BNCT

A characterization of the new Tsing Hua open-pool reactor (THOR) epithermal neutron beam designed for boron neutron capture therapy (BNCT) has been performed. The facility is currently under construction and expected in completion in March 2004. The designed epithermal neutron flux for 1 MW power is 1.7x10(9)n cm(-2)s(-1) in air at the beam exit, accompanied by photon and fast neutron absorbed dose rates of 0.21 and 0.47 mGys(-1), respectively. With (10)B concentrations in normal tissue and tumor of 11.4 and 40 ppm, the calculated advantage depth dose rate to the modified Snyder head phantom is 0.53RBE-Gymin(-1) at the advantage depth of 85 mm, giving an advantage ratio of 4.8. The dose patterns determined by the NCTPlan treatment planning system using the new THOR beam for a patient treated in the Harvard-MIT clinical trial were compared with results of the MITR-II M67 beam. The present study confirms the suitability of the new THOR beam for possible BNCT clinical trials.

Actions of endotoxin and morphine

In summary, our current studies show that treatment with a bacterial endotoxin, lipopolysaccharide (LPS), induces the expression of mu opioid receptors in the rat mesentery. This induction may be mediated through IL-1's actions on mu opioid receptors. Morphine stimulates the expression of adhesion molecules in human brain microvascular endothelial cells (HBMEC) isolated from pathological tissues. Under pathological conditions, mu opioid receptor-dependent pathways may be modulated through the induction of mu opioid receptors, especially in endothelial cells. Treatment with morphine increases [14C]-inulin permeability of an in vitro microvascular endothelial cell barrier, and decreases endothelial cell viability. Morphine pre-treatment potentiates the effects of LPS on endothelial cell viability, and on LPS induction of IL-1beta secretion from 1alpha, 25-dihydroxy-vitamin D3-treated HL-60 human leukemia cells. Previously, it was suggested that an opioid-dependent pathway may be involved in the recovery from endotoxin shock (D'Amato and Holaday, 1984). Induction of mu opioid receptors by treatment with high doses of endotoxin suggests that mu opioid receptor-dependent pathways may be involved in mediating the response to endotoxins. Taken together, these data provide valid evidence for an association between endotoxins and opioid actions. These studies suggest that opioid-dependent pathways in disease or in endotoxin exposure may be modified by cytokine-induced expression of opioid receptors in endothelial cells. In a pathological condition, an alteration of the opioid-dependent pathway may be expected. When morphine is used for its therapeutic values, it may, indeed, potentiate LPS' effects in an adverse manner. From a clinical perspective, these data indicate that morphine and an endotoxin, such as LPS, may interact in a positive 'feedback type of reaction, and thereby modulate the body's immune responses with unexpected and detrimental results.

Chronic morphine potentiates the inflammatory response by disrupting interleukin-1beta modulation of the hypothalamic-pituitary-adrenal axis

Interleukin-1-beta (IL-1beta) can promote inflammation by up-regulating vascular adhesion molecules and inhibit inflammation by activating the hypothalamic-pituitary-adrenal (HPA) axis to produce anti-inflammatory glucocorticoids. In this study, chronic morphine was shown to suppress IL-1beta-induction of corticotropin releasing factor (CRF) mRNA and plasma corticosterone levels. Leukocyte-endothelial adhesion (LEA) in rat mesenteric venules increased during IL-1beta- and FMLP-induced inflammation. Chronic morphine potentiated the LEA response to either IL-1beta or FMLP alone, and greatly enhanced LEA in response to combined IL-1beta and FMLP. Thus, it appears that chronic morphine exposure may promote a potentially damaging inflammatory reaction by disrupting the balance between IL-1beta-mediated local inflammation and the anti-inflammatory effects of the HPA axis.

Residues in Methylosinus trichosporium OB3b methane monooxygenase component B involved in molecular interactions with reduced- and oxidized-hydroxylase component: a role for the N-terminus

Methane monooxygenase (MMO) is a non-heme-iron-containing enzyme which consists of 3 protein components: a hydroxylase (MMOH), an NAD(P)H-linked reductase (MMOR), and a 138-residue regulatory protein, component B (MMOB). Here, NMR spectroscopy has been used to derive interactions between MMOB and reduced and oxidized states of MMOH (245 kDa). Differential broadening of MMOB resonances in 1H-15N HSQC spectra acquired at different molar ratios of MMOH indicates interaction of both proteins, with MMOB binding more tightly to oxidized MMOH as observed previously. The most broadened backbone NH resonances suggest which residues in MMOB are part of the MMOH-binding interface, particularly when those residues are spatially close or clustered in the structure of MMOB. Although a number of different residues in MMOB appear to be involved in interacting with oxidized- and reduced-MMOH, some are identical. The two most common segments, proximal in the structure of MMOB, are beta-strand 1 with turn 1 (residues 36-46) and alpha-helix 3 going into loop 2 (residues 101-112). In addition, the N-terminus of MMOB is observed to be involved in binding to MMOH in either redox state. This is most strongly evidenced by use of a synthetic N-terminal peptide from MMOB (residues 1-29) in differential broadening 1H TOCSY studies with MMOH. Binding specificity is demonstrated by displacement of the peptide from MMOH by parent MMOB, indicating that the peptide binds in or near the normal site of N-terminal binding. The N-terminus is also observed to be functionally important. Steady-state kinetic studies show that neither a delta2-29 MMOB deletion mutant (which in fact does bind to MMOH), the N-terminal peptide, nor a combination of the two elicit the effector functions of MMOB. Furthermore, transient kinetic studies indicate that none of the intermediates of the MMOH catalytic cycle are observed if either the delta2-29 MMOB mutant or the N-terminal peptide is used in place of MMOB, suggesting that deletion of the N-terminus prevents reaction of reduced MMOH with O2 that initiates catalysis.

Comparison of the antiviral activity of hydrophobic amino acid phosphoramidate monoesters of 2'3'-dideoxyadenosine (DDA) and 3'-azido-3'-deoxythymidine (AZT)

A series of hydrophobic, water soluble and non-toxic amino acid phosphoramidate monoesters of dideoxyadenosine (ddA) and 3'-azido-3'-deoxythymidine were shown to inhibit the replication of HIV-1 in human peripheral blood mononuclear cells (PBMC) from two donors. The tryptophan methyl ester phosphoramidates of AZT and ddA were equally potent (EC50S = 0.3-0.4 microM), while the phenyl methyl ester of ddA was 40- to 100- fold more potent than the AZT derivatives. The alaninyl methyl ester of AZT was found to be 70- fold more potent than the ddA derivative. The methyl amide derivatives were found to be 5-20 fold less active than the methyl esters for the ddA series, while for AZT the derivatives were found to be of similar potency or 60- to 166- fold more potent than the methylesters.

Diversity of HLA among Taiwan's indigenous tribes and the Ivatans in the Philippines

Taiwan's indigenous tribes, especially the east coast tribes are not only closely related to Oceania but also with the Australian aborigines. The Ivatans of the Batan Islands in the Philippines are closely related to the Yami tribe of Taiwan as cultural and anthropological studies have shown. Many DRB1 alleles (*15021, *16021, *0404, *04051, *11011, *12021, *1401, *08032) have high allele frequencies (>20%) in certain tribes, suggesting Taiwan's indigenous tribes are homogeneous populations. These high frequency DRB1 alleles and also some HLA-A-B-DR haplotypes found in Taiwan's indigenous tribes are also found in Oceania, Australian aborigines, south and north east Asians and American Indians, lending further support to our previous findings that Taiwan's indigenous tribes are more or less genetically related to both northern and southern Asians, possibly as well as Amerindians. HLA-A*2402 with a remarkably high frequency among Taiwan's indigenous tribes (52.1% approximately 86.3%), especially the central mountain tribes, possibly represents not only founder effects and population bottlenecks, but also positive selection of the allele. Although the Ami tribe has the highest ever reported frequencies of the DRB1*0404 and DRB1*0405, these alleles have not been found to be associated with rheumatoid arthritis as previously described for Caucasians. In addition, DRB1*1401 has a high frequency in most tribes but is not associated with psoriasis as previously indicated in some studies, suggesting the involvement of some additional genetic and/or environmental factors mechanism in the development of these diseases.

Phase determination and extension using X-ray multiple diffraction and the maximum-entropy method

The extension of the phases of the structure factors of the organic crystal C(25)H(25)NO(2) from 77 starting individual phases using the maximum-entropy method is reported. These starting phases were determined from 90 experimental triplet phases calculated from 215 measured psi-scan three-beam and four-beam diffraction profiles obtained with a rotating-anode X-ray source, where the psi scans were around the reciprocal-lattice vectors of the 001, 002 and 003 reflections. The extension of the structure factors with phase values was carried out using the maximum-entropy method for 2040 measured two-beam Bragg diffraction intensities with 77 starting phases and the symmetry of the space group as the constraints. Use of structure-factor triplets as constraints for entropy maximization was also attempted. The minimum chi(2) criteria were applied to the maximum-entropy extrapolation to discern the best phase set to be used as the new constraints for the next step of generating new phases. With this phase-extension procedure, more than 100 phases were determined and an electron-density map at 1.97 A was deduced.

Dexamethasone affects cytokine-mediated adhesion of HL-60 human promyelocytic leukemia cells to cultured dermal microvascular endothelial cells

Leukocyte endothelial adhesion (LEA) is the prelude to a complex cascade of reactions following an immunological challenge. Recently, LEA has been implicated in the molecular basis of several dermatological disorders. While the role of proinflammatory cytokines, such as interleukin-1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), in LEA has been investigated using nondermal models, limited data exist regarding their effects on LEA in dermal models. This study shows that cotreatment of cultured human dermal endothelial cells (CADMEC) with IL-1beta and TNF-alpha resulted in a marked increase in the adherence of human promyelocytic leukemia (HL-60) cells to CADMEC and an increase in expression of intercellular adhesion molecule-1 and E-selectin. Pretreatment of CADMEC with dexamethasone, a long-lasting glucocorticoid, resulted in a decrease in both HL-60 cell adhesion to CADMEC and adhesion molecule expression. Taken together, these data demonstrate that LEA may play a role in inflammatory skin conditions and in the mechanisms underlying the potential use of glucocorticoids as a treatment option.

Polarization-resolved output analysis of X-ray multiple-wave interaction

The polarization suppression of the interfering components in X-ray multiple-wave interaction is observed for the first time by using a polarization analyzer with an arbitrary inclination of the diffraction plane with respect to that of the investigated crystal. The condition for total suppression of the multiple-wave interaction outside the investigated crystals by a polarization analyzer is derived theoretically from the modified Born approximation. By means of the partial suppression of the strong interfering component, the increase in the visibility of multiple-wave interference is experimentally and theoretically demonstrated. The proposed experimental polarization-resolved technique provides an operational way to enhance the visibility of X-ray multiple-wave interaction outside the investigated crystals for direct phase determination.

Anomalous dispersion behavior of multiple-wave X-ray diffraction at absorption edges: determination of phase change at resonance

The effects of anomalous dispersion (resonance) on multiple reflection of x rays and their interference in crystals at atomic absorption edges are studied. Intensity ratios of two inversion-symmetry-related multiple diffractions at or near absorption edges exhibit highly phase-sensitive profiles with strong asymmetric characteristics, unlike those far from the edges. A new resonance perturbation Bethe approach is developed to explain this behavior. This leads to direct determination of the phase change for x-ray reflections at resonance.

The origin of Minnan and Hakka, the so-called "Taiwanese", inferred by HLA study

The Minnan and Hakka people groups, the so-called "Taiwanese", are the descendants of early settlers from the southeast coast of China during the last few centuries. Genetically they showed affinities to southern Asian populations, as determined by phylogenetic trees and correspondence analysis calculated from HLA allele frequencies. This corresponds historically with the fact that they are the descendants of the southeast coastal indigenous population (Yueh) of China and should therefore not be considered as descendants of "pure" northern Han Chinese. A33-B58-DRB1*03 (A33-Cw10-B58-DRB1*03-DQB1*02), the most common HLA haplotype among "Taiwanese", with a haplotype frequency of 6.3%, has also been found to be the most common haplotype among Thai-Chinese and Singapore Chinese, two other populations also originating from the southeast coast of China. These observations suggests that this haplotype is the most well-conserved ancient haplotype of the Yueh.

Comparison of in vitro growth-inhibitory activity of carboplatin and cisplatin on leukemic cells and hematopoietic progenitors: the myelosuppressive activity of carboplatin may be greater than its antileukemic effect

BACKGROUND

Carboplatin [cis-diammine(cyclobutane-1, 1-dicarboxylato)platinum(II)] has been shown to be an active agent for acute myeloid leukemia. This second-generation platinum drug has less nephrotoxicity and ototoxicity but more myelotoxicity than does the first-generation platinum drug cisplatin. The study was designed to elucidate whether their myelosuppressive activities equal their antileukemic effects.

METHODS

Cisplatin and carboplatin were used to treat four leukemic cell lines (CEM, HL60, K562 and U937), blast cells from 10 leukemic patients and hematopoietic progenitors from five umbilical cord blood samples.

RESULTS

The mean IC50 of leukemic cell lines was 0.4 and 6.2 microg/ml, the mean IC50 of patients' leukemic blasts was 2.0 and 22.4 microg/ml and the mean IC50 of hematopoietic progenitors (BFU-E, CFU-E and CFU-GM) was 1.8 and 1.7 microg/ml for cisplatin and carboplatin, respectively.

CONCLUSIONS

Carboplatin required a 10 times higher drug concentration than cisplatin to induce a similar degree of growth inhibition on leukemic cells. However, the hematopoietic progenitors responded equally to cisplatin and carboplatin at the same drug concentration. The results suggest that the myelosuppressive activity of carboplatin is greater than its antileukemic effect.

Early patterning of prelimbic cortical axons to the striatal patch compartment in the neonatal mouse

The striatum receives excitatory input from virtually the entire cerebral cortex. In the adult, this input is segregated into two functionally distinct compartments of the striatum, the patch (striosome) and matrix regions. This study determined whether the patterning of corticostriatal afferents from the prelimbic cortex to the striatal patch compartment develops during the early period of collateral formation or instead at the time of peak synaptogenesis. Initial formation of corticostriatal axon collaterals was observed by embryonic day (E) 19. Quantification of corticostriatal collaterals revealed a significant increase in the number and complexity of collateral branches at postnatal day 6 as compared to E19. Concomitant with the increase in collateral branching, a heterogeneous pattern of collateralization consisting of parallel rows of corticostriatal collaterals was observed in the medial striatum. In addition to the rows, clusters of corticostriatal axons occurred more laterally. These clusters colocalized with patches of dense tyrosine hydroxylase-positive fibers, a marker for the striatal patch compartment in the neonatal mouse. Together, these data indicate that corticostriatal patterning occurs during the period of early axon collateralization resulting in a segregation of corticostriatal axon collaterals from the prelimbic cortex to the striatal patch compartment.

Endomorphin-1 and endomorphin-2 induce the expression of c-FOS immunoreactivity in the rat brain

Using FOS immunoreactivity (FOSir) as an anatomical marker of neuronal activation, we examined the effects of intracerebroventricular (i.c.v.) injections of endomorphin-1 (EM-1) and endomorphin-2 (EM-2) in the rat brain to determine the sites of action of these two mu-opioid ligands. Radiant heat tail flick latency, as a measure of behavioral effects, was prolonged by either EM-1 or EM-2 administration. Dose-dependent EM-1- and EM-2-induced FOSir were observed in various nuclei throughout the rostral-caudal axis of the rat brain. While there was some overlap, EM-1-induced FOSir was more prevalent than EM-2. The pattern of EM-induced FOSir was similar to the distribution of EM immunoreactivity (EMir). However, some sites with little or no detectable EMir exhibited FOSir, while other nuclei with marked EMir showed only sparse FOSir. EM-induced FOSir was correlated with mu-opioid receptor location in most brain areas. However, EM-induced FOSir was absent in the caudate putamen and the accumbens nucleus, both areas of high mu-opioid receptor density.

Role of type III collagen in bladder filling

The function of the urinary bladder is to store urine at low pressure and expel it periodically. To accomplish this, it must have the appropriate structural properties to accommodate slow but continuous volume changes. While much is presently known about the functional measurements of compliance, relatively little is known about the structural basis of compliance. In the present study, immunohistochemistry has been used to localize type III collagen fibers in the bladder wall at different intravesical volumes. To improve the resolution of these fibers, confocal microscopy was utilized to determine the changes in type III collagen fiber orientation and correlate them with the degree of mechanical distension of the bladder wall at partial and full capacity. We demonstrate that there were significant changes in both the orientation and conformation of type III collagen fibers during bladder filling. These observations support the view that volume accommodation in the bladder is achieved by changes in the arrangement of type III collagen. These data suggest that abnormal deposition or arrangement of type III collagen fibers can have an impact on normal bladder function.

Survey of Spirometra erinaceieuropaei in frogs in Taiwan and its experimental infection in cats

Eighteen of 56 (32.1%) wild Rana limnocharis from central and south Taiwan were found to contain plerocercoids of Spirometra erinaceieuropaei. This is the first report of S. erinaceieuropaei infections in frogs in Taiwan, with the plerocercoids being recovered from the thigh and back muscles or under the skin. Other species of frogs examined, including nine wild R. latouchii, one wild Buergeria robustus and 110 cultured R. rugulosa were free of infection. The plerocercoids were orally inoculated into four cats; three of which were each given a single plerocercoid and one a dose of three plerocercoids. Daily faecal examination showed that two cats started shedding eggs of S. erinaceieuropaei on day 8 postinfection (PI) and the other two on day 10 PI. The highest eggs per gram and eggs per day for a single worm was found to be 428,000 and 14,416,000 respectively. Only the cat inoculated with three plerocercoids shed proglottids in its faeces during the 2 month observation period.

MDM2 mRNA expression is a favorable prognostic factor in non-small-cell lung cancer

MDM2 is one of the downstream target genes for transcriptional activation by the product of the p53 tumor-suppressor gene. Transactivation of MDM2 gene expression is represented by the presence of a functional p53 protein. We hypothesized that MDM2 mRNA expression may be a more suitable prognostic factor than p53 or MDM2 protein expression and p53 gene mutations. In this study, expression of MDM2 mRNA, p53 protein, and MDM2 protein and mutations of the p53 gene were assessed in 81 lung tumor tissue specimens using RT-PCR, immunohistochemistry, and direct sequencing among exons 5-8, respectively. By immunohistochemistry, 33 and 42 of 81 patients with p53 (40.7%) and MDM2 (51.5%) protein expression were found in lung tumor specimens, respectively. The p53 direct sequencing data indicated that 13 of 81 patients (16.0%) had p53 mutations. However, Kaplan-Meier analysis showed that p53 protein and MDM2 protein expression and p53 mutation were not useful as prognostic factors. Interestingly, the survival of patients with MDM2 mRNA expression was longer than that of patients without MDM2 mRNA expression, though MDM2 mRNA expression was not associated with clinicopathological parameters, including tumor grade, tumor stage, tumor type, and TNM values. Moreover, Cox regression analysis showed that MDM2 mRNA expression was a significantly independent favorable prognostic factor in non-small-cell lung cancer (NSCLC) patients. Thus, measuring MDM2 mRNA expression using RT-PCR may be a simple, useful approach for predicting the survival of NSCLC patients.

The effect of electroporation on iontophoretic transdermal delivery of calcium regulating hormones

Electrically-assisted delivery by iontophoresis and/or electroporation was used in vitro to deliver the calcium regulating hormones, salmon calcitonin (sCT) and parathyroid hormone (1-34) (PTH) through human epidermis. Such delivery could be useful for chronic treatment of post-menopausal osteoporosis and other clinical indications as a superior alternative to parenteral delivery. sCT (50 microg/ml) or PTH (1-34) (100 microg/ml) formulation was prepared in citrate buffer (pH 4.0 or 5.0, respectively). Epidermis separated from human cadaver skin was used. Iontophoresis was applied using a constant current power source and electroporation with an exponential pulse generator. Silver/silver chloride electrodes were used. A combination of electroporation and iontophoresis resulted in higher transdermal permeation than either one technique alone. Electroporation also shortened the lag time of iontophoretic transdermal delivery of salmon calcitonin. Pulsing at lower voltages followed by iontophoresis did not result in increased transport (over iontophoresis alone), perhaps because the transdermal voltage was very low. The transdermal transport of salmon calcitonin by pulsing with 15 pulses (1 ppm) of 500 V (200 ms) followed by iontophoresis led to a quick input and high flux. The average transdermal voltage was only about 50 V for a 500 V study.

Chronic cocaine alters hemodynamics and leukocyte-endothelial interactions in rat mesenteric venules

We investigated the effects of chronic cocaine exposure on the microcirculation in the rat mesenteric venules under both non-inflammatory and FMLP-induced inflammatory conditions. Chronic cocaine significantly increased WBC rolling flux in both conditions, and potentiated FMLP-induced leukocyte-endothelial cell adhesion (LEA). In cocaine-treated animals, total WBC number increased by 91%, and the ratio of white blood cell to red blood cell velocity was significantly lower, while vessel diameter was unchanged. Chronic cocaine decreased serum levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6), but had no effect on interleukin-1 beta (IL-1beta). Expression of intercellular adhesion molecule-1 (ICAM-1) was increased in mesenteric venules following chronic cocaine exposure, and may be one of the mechanisms underlying enhancement of FMLP-induced LEA. The increase in WBC count, WBC flux and LEA, and the change in cell velocity seen in the cocaine-treated animals could cause a decrease in effective vessel diameter and a change in intravascular resistance, and may underlie the progressive vascular damage seen in chronic cocaine-abusing individuals.

Management of scrap computer recycling in Taiwan

It is estimated that approximately 300,000 scrap personal computers are generated each year in Taiwan [S.-L. Chang, A Study on the Scrap Computer Treatment Cost, Environment Protection Administration of Taiwan, December 1998 (in Chinese)]. The disposal of such a huge number of scrap computers presents a difficult task for the island due to the scarcity of landfills and incineration facilities available locally. Also, the hazardous materials contained (i.e., phosphor coatings of cathode ray tubes (CRTs), batteries, polychlorinated biphenyl capacitors, mercury-containing parts, liquid crystal display, high-lead content CRT funnel glass, and plastic containing flame-retardant bromine, etc.) in the scrap computers may seriously pollute the environment if they are not properly disposed of. Therefore, the EPA of Taiwan declared scrap personal computers the producer's recycling responsibility as of July 1997. Under this decree, the manufacturers, importers and sellers of personal computers have to properly recover and recycle the scrapped computers which they originally sell. On June 1, 1998, a producer responsibility recycling program for scrap computers was officially implemented in Taiwan. Under this program, consumers can bring their unwanted personal computers to the designated collection points and receive reward money. Currently, only six computer items are mandated to be recycled in this recycling program. They are notebooks, monitors, hard disks, power supplies, printed circuit boards and main frame shells. This article outlines the current scrap computer recycling system in Taiwan.

Transdermal iontophoretic delivery of salmon calcitonin

Electrically enhanced transdermal delivery of salmon calcitonin could be useful for chronic treatment of postmenopausal osteoporosis and other clinical indications as a superior alternative to parenteral delivery. Calcitonin (50 microg/ml) formulation was prepared in citrate buffer (pH 4.0). Epidermis separated from human cadaver skin was used. Most iontophoresis studies were done at a current density of 0.5 m A cm2. Silver/silver-chloride electrodes were used and calcitonin was found to be best delivered under the anode. The relationship between calcitonin flux and current density during iontophoresis was linear. Passive flux was zero. Flux increased with increasing concentration up to 250 microg/ml but then it levels off. Thus, transdermal delivery of salmon calcitonin may be accomplished to achieve therapeutic levels.

In vitro biocytin injection into perinatal mouse brain: a method for tract tracing in developing tissue

Injection of biocytin provides an effective method for labeling axonal projections. Several difficulties arise when this technique is employed in fetal or early postnatal animals in vivo, including limited access to injection sites and extended post-injection survival periods. To circumvent these problems, we adapted the technique of extracellular biocytin injection for use in explanted brain hemispheres of developing mice. Briefly, entire brain hemispheres from perinatal mice (E16-P9) were removed and placed in oxygenated aCSF in a brain slice recording chamber. Following visually guided injection of biocytin (2%) into the prelimbic cortex, the brains were then incubated in oxygenated artificial cerebrospinal fluid (aCSF) for varying periods of time and then immersion-fixed in 4% paraformaldehyde and 0.5% glutaraldehyde. The next day, the brains were sectioned and processed for biocytin histochemistry using the avidin-biotin-complex method. We examined the method of injection, electrode type, time of injection, and post-injection incubation period. We found that in E16-P9 animals iontophoresis of biocytin using 8- to 12-megaohm patch clamp electrodes for a duration of 10 min provides optimal axonal labeling. Post-injection incubation times of four or more hours are sufficient for labeling fine caliber collaterals as well as axon bundles that reach distances over 3 mm. In vitro injection of biocytin into explanted brain hemispheres provides a quick and easy method for tract tracing in developing brains.

Quantification of the learning curve for percutaneous dilatational tracheotomy

OBJECTIVES/HYPOTHESIS

Although numerous investigators have reported a bedside percutaneous dilatational tracheotomy (PDT) complication incidence similar to that of standard operative tracheostomy, others have proposed a "learning curve" for PDT resulting in increased complications early in individual or institutional experience with this procedure. The objective of this investigation is to characterize and quantify the proposed learning curve for PDT.

STUDY DESIGN

Prospective analysis of complication incidence for the first 100 PDT procedures performed in a local community hospital Department of General Surgery.

METHODS

Demographic data, patient disease variables, and patient anatomic features, as well as perioperative, postoperative, and late complications, were recorded prospectively. Patients were divided into sequential cohorts of 20 and were evaluated for complications at regular intervals.

RESULTS

Perioperative and late complication incidence was significantly higher in the first 20 patients who underwent PDT. However, postoperative complication incidence did not significantly vary with operator or institutional experience. In addition, patients with suboptimal anatomy were found to have a significantly increased complication incidence, independent of operator and institutional experience.

CONCLUSIONS

Percutaneous dilational tracheotomy has an identifiable learning curve that is most prominent in the first 20 patients treated. Early experience with PDT should be obtained under controlled circumstances, ideally the operating suite. Although most complications occur during acquisition of early experience with PDT, certain life-threatening complications such as tube dislodgment or inability to complete procedure may occur even after extensive experience is obtained. Bedside PDT has an acceptable complication incidence, but any surgeon employing this technique must be prepared to perform immediate standard open tracheotomy to minimize potentially lethal complications of this elective procedure.

Heterogeneity of Taiwan's indigenous population: possible relation to prehistoric Mongoloid dispersals

Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.

Characterization of a 5'-flanking region supporting the transcription of mouse thymosin beta-4 in mouse NIH3T3 cells

Expression of the gene coding for thymosin beta-4 (Tbeta-4), the major G-actin sequestering peptide in the cell, is regulated mainly at the level of transcription. In this study, we examined the nucleotide sequence of the 5'-flanking region (from -2202 to -881) of the mouse Tbeta-4 gene, and demonstrated that the DNA fragment from -278 to +410 of this gene was capable of directing the expression of a chloramphenicol acetyltransferase reporter gene in NIH3T3 cells. However, expression of the reporter gene in cells cannot be induced by interferon-alpha treatment even though a rapid activation of endogenous Tbeta-4 gene by this cytokine was observed. These results suggest that the projected interferon-stimulated response element (ISRE) might reside in other parts of the mouse Tbeta-4 gene.

Synthesis and antiviral activity of amino acid carbamate derivatives of AZT

Lipophilic amino acid methyl ester and methyl amide carbamates of 3'-azido-3'-deoxythymidine (AZT) were synthesized and their anti-HIV-1 activity in PBMCs was determined. The methyl amides were more potent (EC50s = 1.8-4.0 microM) than the methyl esters (EC50s = 2.0-20 microM). Carbamate hydrolysis by cell lysates and liberation of AZT was not observed for representative methyl ester or methyl amide AZT carbamates. No evidence of direct inhibition of HIV reverse transcriptase or integrase was observed.

Roles of the lamina propria and the detrusor in tension transfer during bladder filling

In this study, structural changes within the lamina propria and detrusor layers were analysed during development as a function of bladder filling. Second-, third- and full-term foetal bovine bladders were filled to 0%, 25%, 50%, 75% and 100% of their total capacity and snap frozen. The bladders were analysed histochemically and the relative thicknesses of the lamina propria and detrusor were measured. In all gestational stages examined, the total thickness of the bladder wall decreased during bladder filling. The lamina propria of the full-term bladder thinned at a consistently faster rate than did the detrusor. The lamina propria of second and third trimester bladders followed the same thinning pattern, except when the bladders were filled from 25% to 50% of their capacities. At these gestational stages, the detrusor thinned at a faster rate than the lamina propria. Our results demonstrate that the detrusor layer carries tension only during a specific portion of the filling cycle and only during the second and third trimesters. We conclude that the lamina propria acts as the capacitance layer, while the detrusor functions as the "limiting" or "girding" layer to prevent over-distension of the bladder wall.

Solution structure of component B from methane monooxygenase derived through heteronuclear NMR and molecular modeling

Methane monooxygenase (MMO) is a nonheme iron-containing enzyme which consists of three protein components: a hydroxylase (MMOH), an NADH-linked reductase (MMOR), and a small "B" component (MMOB) which plays a regulatory role. Here, 1H, 13C, 15N heteronuclear 2D and 3D NMR spectroscopy has been used to derive the solution structure of the 138 amino acid MMOB protein in the monomer state. Pulse field gradient NMR self-diffusion measurements indicate predominant formation of dimers at 1 mM MMOB and monomers at or below 0.2 mM. MMOB is active as a monomer. Aggregate exchange broadening and limited solubility dictated that multidimensional heteronuclear NMR experiments had to be performed at a protein concentration of 0.2 mM. Using 1340 experimental constraints (1182 NOEs, 98 dihedrals, and 60 hydrogen bonding) within the well-folded part of the protein (residues 36-126), MMOB structural modeling produced a well-defined, compact alpha/beta fold which consists of three alpha-helices and six antiparallel beta-strands arranged in two domains: a betaalphabetabeta and a betaalphaalphabetabeta. Excluding the ill-defined N- and C-terminal segments (residues 1-35 and 127-138), RMS deviations are 1.1 A for backbone atoms and 1.6 A for all non-hydrogen atoms. Compared to the lower resolution NMR structure for the homologous protein P2 from the Pseudomonas sp. CF600 phenol hydroxylase system (RMSD = 2.48 A for backbone atoms) (Qian, H., Edlund, U., Powlowski, J., Shingler, V., and Sethson, I. (1997) Biochemistry, 36, 495-504), that of MMOB reveals a considerably more compact protein. In particular, MMOB lacks the large "doughnut" shaped cavity reported for the P2 protein. This difference may result from the limited number of long-range NOEs that were available for use in the modeling of the P2 structure. This NMR-derived structure of MMOB, therefore, presents the first high-resolution structure of a small protein effector of a nonheme oxygenase system.

Cocaine enhances brain endothelial adhesion molecules and leukocyte migration

Leukocyte infiltration of cerebral vessels in cocaine-associated vasculopathy suggests that cocaine may enhance leukocyte migration. We have investigated cocaine's effects on leukocyte adhesion in human brain microvascular endothelial cell (BMVEC) cultures and monocyte migration in an in vitro blood-brain barrier (BBB) model constructed with BMVEC and astrocytes. Cocaine (10(-5) to 10(-9) M) enhanced adhesion of monocytes and neutrophils to BMVEC. In the BBB model, cocaine (10(-4) to 10(-8) M) enhanced monocyte transmigration. Cocaine increased expression of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1, CD54), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1) on BMVEC. The peak effect on ICAM-1 expression was between 6 and 18 h after treatment. ICAM-1 was increased by cocaine in BMVEC, but not in human umbilical vein endothelial cells, and the enhancement was greater in a coculture of BMVEC with monocytes. ICAM-1 expression was enhanced by a transcriptional mechanism. Polymyxin B inhibited up-regulation of adhesion molecules by LPS but not by cocaine. In LPS-activated BMVEC/monocyte coculture, cocaine increased secretion of tumor necrosis factor-alpha and interleukin-6. Taken together, these findings indicate that cocaine enhances leukocyte migration across the cerebral vessel wall, in particular under inflammatory conditions, but the effects are variable in different individuals. Cocaine's effects are exerted through a cascade of augmented expression of inflammatory cytokines and endothelial adhesion molecules. These could underlie the cerebrovascular complications of cocaine abuse.

Antiviral nucleoside drug delivery via amino acid phosphoramidates

Stable and water soluble amino acid phosphomonoester amidates of AZT were synthesized and shown to have potent anti-HIV-1 activity. Intracellular and cell extract metabolism studies revealed that these compounds are likely to be enzymatically converted to the corresponding monophosphates. In addition, we have shown that the half life and tissue distribution of a phosphoramidate of AZT is 5 and 10-fold greater, respectively, than AZT.

A case of extraadrenal pheochromocytoma associated with adrenal cortical nodular hyperplasia and papillary thyroid carcinoma

A 64-year-old woman was admitted in November, 1996 for fluctuating blood pressure. There was multinodular goiter in her neck. High urine VMA and serum aldosterone were noted. Computed tomography showed an oval lesion in the left adrenal gland. Left adrenalectomy was performed and the pathology was proved to be adrenal cortical nodular hyperplasia. Fluctuating blood pressure and high urine VMA persisted after the operation. CT scan of the abdomen revealed a soft tissue mass in lower abdomen. The patient was admitted again in September, 1997. Laboratory examinations showed normal serum aldosterone, normal plasma renin activity and high urine VMA. Aspiration cytology of the thyroid gland disclosed papillary thyroid carcinoma. [131I]-metaiodobenzylguanidine image revealed a high uptake lesion in the right L-3 paravertebral area. Tumor excision and thyroidectomy were performed. The pathology was reported as extraadrenal pheochromocytoma and papillary thyroid carcinoma. Papillary thyroid carcinoma is rarely associated with pheochromocytoma. To our knowledge, this paper is the first report of a patient with extraadrenal pheochromocytoma associated with papillary thyroid carcinoma and adrenal cortical nodular hyperplasia.

An insulin-dependent hypoglycaemia induced by electroacupuncture at the Zhongwan (CV12) acupoint in diabetic rats

Acupuncture at the Zhongwan acupoint has been widely used in traditional Chinese medicine to relieve symptoms of diabetes mellitus. Our study investigated the effect on plasma glucose of electroacupuncture applied at the Zhongwan acupoint in rat diabetic models. Plasma concentrations of insulin, glucagon and beta-endorphin- were also determined using radioimmunoassay. A decrease in plasma glucose was observed in rats after electroacupuncture (15 Hz, 10 mA) for 30 min at the Zhongwan acupoint. This was observed in normal rats and rat models with Type II (non-insulin-dependent) diabetes mellitus. No significant effect on plasma glucose was observed in rat models with Type I (insulin-dependent) diabetes mellitus: neither the streptozotocin (STZ)-induced diabetic rats nor the genetic (BB/W) rats. Further, the hypoglycaemic action of electroacupuncture stimulation disappeared in rats with insulin-resistance induced by an injection of human long-acting insulin repeated daily to cause the loss of tolbutamide-induced hypoglycaemia. An insulin-related action can thus be hypothesised. This hypothesis is supported by an increase in plasma insulin-like immunoreactivity after electroacupuncture stimulation in normal rats. Participation of glucagon was ruled out because there was no change in plasma glucagon-like immunoreactivity resulting from electroacupuncture stimulation. In addition to an increase in plasma beta-endorphin-like immunoreactivity, the plasma glucose lowering action of electroacupuncture stimulation at Zhongwan acupoint was abolished by naloxone in a sufficient dose to block opioid receptors. Thus we suggest that electroacupuncture stimulation at the Zhongwan acupoint induces secretion of endogenous beta-endorphin which reduces plasma glucose concentration in an insulin-dependent manner.

Cocaine opens the blood-brain barrier to HIV-1 invasion

Cocaine abuse has been associated with vasculitis and stroke, and is suspected to influence the progression of AIDS dementia. Cocaine may enhance HIV-1 neuroinvasion by actions directed at the blood-brain barrier. HIV-1 appears to penetrate the human brain microvascular endothelial cell barrier by a paracellular route breached by tumor necrosis factor-alpha (TNF-alpha). Cocaine's effects on the blood-brain barrier were investigated using human brain microvascular endothelial cells and peripheral blood monocytes. Cocaine (10(-5) M and 10(-6) M) increased molecular permeability of the barrier and viral invasion by the macrophage-tropic HIV-1(JR-FL) into the brain chamber. Cocaine also augmented apoptosis of brain endothelial cells and monocytes, increased secretion of four chemokines (interleukin-8, interferon-inducible protein-10, macrophage inflammatory protein-1alpha, and monocyte chemoattractant protein-1) and the cytokine, TNF-alpha, by human monocytes. TNF-alpha enhanced invasion of the brain compartment by macrophage-tropic, lymphotropic, and bitropic HIV-1 strains. These data indicate that HIV-1 neuroinvasion can be increased by (a) cocaine's direct effects on brain microvascular endothelial cells and (b) paracrine effects of cocaine-induced pro-inflammatory cytokines and chemokines on the blood-brain barrier.