Incorporation of a fiber Bragg grating to improve the efficiency of a 1580-nm-band tunable fiber ring laser

An efficient and tunable 1580-nm-band erbium-doped fiber ring laser is achieved by injection of amplified spontaneous emission in a conventional band by a fiber Bragg grating into the gain medium. The insertion of the fiber Bragg grating reduces the lasing threshold to 25%. The tuning range is 1560-1610 nm; the side-mode suppression ratio is better than 65 dB.

Effects of risperidone on information processing and attention in first-episode schizophrenia

Risperidone appears to have a beneficial effect in several areas of cognitive function in schizophrenic patients. In previous studies, however, the clinical characteristics of the subjects differed between studies, and were heterogeneous even in single study. Most of the subjects were previously exposed to different kinds of neuroleptics and some of them were treatment-resistant. The aim of this study is to evaluate the effect of risperidone on attention and information processing in a homogeneous subgroup of schizophrenic patients, i.e. drug-naïve first-episode inpatients. In the patient group (n=17), cognitive tests and clinical assessments were performed before and after 8 weeks of risperidone treatment. The same cognitive tests were administered to the control group (n=24). The delay between test and retest was 8 weeks. Before treatment, the patient group performed significantly worse than control group on the tests measuring continuous attention, vigilance, and the speed of information processing. After treatment (the average dose of risperidone was 7.3mg/day), in spite of significant improvement of the clinical symptoms, the patients did not show any significant improvement or worsening in most of the items of these tests. The control group did not show any practice effect. These results suggest that first-episode schizophrenic patients have deficits in sustained attention and vigilance to visual stimuli, as well as the speed of information processing to visual and auditory stimuli, and these deficits are unrelated to clinical symptoms and remain stable during the early phase of treatment. This study did not receive pharmaceutical company financial support.

Role of caspases in human renal proximal tubular epithelial cell apoptosis

In the present study, we have used an in vitro model of apoptosis using primary human renal proximal tubular epithelial (RPTE) cells to investigate the mechanisms involved in renal cell apoptosis. Treatment of RPTE cells with okadaic acid for 24-48 h induced apoptosis in a concentration-dependent manner. Apoptosis was accompanied by the activation of the p38 mitogen-activated protein kinase (MAPK) pathway followed by the activation of caspase-9, -3, and -7. The induction of caspase activity correlated with the proteolytic cleavage of beta-catenin, suggesting that beta-catenin is a caspase substrate. The caspase inhibitor, Z-Val-Ala-Asp-fluoromethylketone (Z-VAD-fmk), resulted in a dose-dependent inhibition of apoptosis and beta-catenin cleavage. These data suggest that okadaic acid-induced apoptosis is p38 MAPK and caspase-dependent and that proteolytic cleavage of beta-catenin by caspases is likely to be a downstream molecular event associated with the morphological and cytoskeletal changes induced during apoptosis.

Hydroxo-bridged Cubane-type tetrairon(II) clusters supported by sterically-hindered carboxylate ligands

A series of hydroxo-bridged cubane-type tetrairon(II) clusters, [Fe(4)(mu-OH)(4)(mu-O(2)CAr(4)(-)t(BuPh))(2)(mu-OTf)(2)L(4)] (L = C(5)H(5)N (1), 4-(t)BuC(5)H(4)N (2), 3-FC(5)H(4)N (3)), were synthesized by using a sterically hindered carboxylate ligand, 2,6-di(4-tert-butylphenyl)benzoate (Ar(4)(-)t(BuPh)CO(2)(-)). Three different bridging units that mediate weak antiferromagnetic coupling interactions between the metal centers support the unprecedented cubane-type [Fe(4)(mu-OH)(4)](4+) cores in 1-3. The solution structures of 1 and 3 probed by FT-IR and (19)F NMR spectroscopy are consistent with the solid-state geometry determined by X-ray crystallography. Zero-field Mössbauer spectra of 1-3 at 4.2 K are characteristic of high-spin iron(II) centers in nearly identical coordination environments. Compound 1 undergoes two irreversible oxidation processes at ca -10 and +880 mV (vs Fc/Fc(+)), the former approaching quasi-reversible behavior with increased scan rates and a narrow potential sweep range. Comparisons are made with analogous known [Fe(4)X(4)](n)()(+) (X = O, S) units, and the structural integrity of tetrairon fragments upon a change in oxidation state is discussed together with some possible biological implications.

Positron emission tomography in the evaluation of stage III and IV head and neck cancer

BACKGROUND

Detection of metastatic disease in head and neck cancer patients is critical to preoperative planning, because patients with distant metastasis will not benefit from surgical therapy. Conventional radiographic modalities, such as CT and MR, give excellent anatomic detail but poorly identify unenlarged lymph nodes harboring metastatic disease.

OBJECTIVE

A pilot study was conducted to evaluate the usefulness of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) detection of metastatic disease in patients with advanced-stage head and neck cancer.

METHODS

Total body FDG-PET imaging was performed in a prospective manner on 12 consecutive patients with a new diagnosis of stage III or IV mucosal squamous cell carcinoma of the head and neck. Chest CT was also performed on all 12 patients. Patients found to have metastatic disease on either CT or PET imaging underwent procedures to obtain histopathologic confirmation of disease.

RESULTS

Three patients (25%) had FDG-PET scans demonstrating metastatic disease. Two of these patients had no evidence of disease on chest radiograph or chest CT but were noted to have positive FDG-PET imaging within the mediastinal lymphatics. Mediastinoscopy was performed confirming metastatic disease in these patients. The third patient had a peripheral lung lesion detected on chest radiograph, CT, and FDG-PET. This nodule was diagnosed by CT-guided biopsy as squamous cell carcinoma.

CONCLUSION

FDG-PET scanning detected mediastinal disease in two patients (17%) with advanced-stage head and neck squamous cell carcinoma that was not identified with conventional imaging techniques. PET imaging seems to have significant potential in the detection of occult metastatic disease, particularly in the mediastinal lymphatics.

Aging and neuro-AIDS conditions and the changing spectrum of HIV-1-associated morbidity and mortality

Older individuals (>50 years of age) now comprise over 11% of patients with AIDS in the United States. This percentage is expected to continue to grow, due both to the improved longevity of patients prescribed highly active antiretroviral therapy (HAART) and to new infections among older individuals. This review focuses on the neuropsychiatric and neurological conditions that are most likely to be affected by advancing age-HIV-1-associated cognitive-motor disorder, peripheral neuropathy, progressive multifocal leukoencephalopathy, primary CNS lymphoma, and risk for cerebrovascular accident. Age associations with incidence of these disorders and with treatment foci are specified. Implications for future changes in management are discussed.

Monoclonal antibodies: a new era in the treatment of non-Hodgkin's lymphoma

Monoclonal antibodies (MAbs) have been used as therapeutic agents for many years. In 1997, Rituxan (IDEC-C2B8, rituximab, MabThera) became the first MAb to be approved by the FDA for a cancer indication. Rituxan served to heighten interest in the therapeutic applications of MAbs. Herceptin (for patients with breast cancer) and Mylotarg (for patients with acute myeloid leukemia) were approved shortly thereafter. Literally dozens of antibodies are currently under investigation for a variety of malignant and non-neoplastic indications. Rituxan is effective in patients with low-grade or follicular, relapsed or refractory non-Hodgkin's lymphoma (NHL). The response rate and time to progression (responders) are in the 50% and 13 months range, respectively. It is also active in intermediate-grade NHL where a large randomized study, in combination with CHOP chemotherapy, has shown a statistically significant increase in complete response (CR) rate (75% vs. 60%), prolongation of 1 year event-free survival (69% vs. 49%) and of overall survival (83% vs. 68%) as compared to CHOP alone. This marks the first time that any agent has shown results superior to CHOP, the curative gold standard for this type of NHL. Other promising antibodies under clinical investigation include: Hu1D10; Anti CD19, 22, 52, and anti-Id antibodies. The safety profile, clinical activity, and mechanism of action of these MAbs make them ideal candidates for combination with chemotherapy or biologicals. Over the next few years, we will see very significant therapeutic advances emerge as this important research yields additional clinical results.

Structure-based combinatorial library design: discovery of non-peptidic inhibitors of caspases 3 and 8

Structure-based design of a combinatorial array was carried out in order to identify non-peptidic thiomethylketone inhibitors of caspases 3 and 8. Five compounds from the designed array were active against caspase 3, and two were active against caspase 8. A 2.5-A resolution co-crystal structure of caspase 3 and a thiomethylketone array member is reported. The structure-based design strategy has proved useful for identifying caspase inhibitors.

The role of state-of-the-art echocardiography in the assessment of myocardial injury during and following cardiac surgery

Use of intraoperative echocardiography during open heart surgery, transesophageal probes, high-frequency transducers, and color Doppler imaging provide important diagnostic information to surgeons and anesthesiologists. Early detection of myocardial ischemia, assessment of valvular disorders, and the ability to monitor for intracardiac air are among the most important roles of intraoperative transesophageal echocardiography. Large prospective studies are necessary to evaluate whether these changes affect the outcome of patients undergoing coronary artery bypass grafting in terms of morbidity, mortality, hospital length of stay, and functional recovery. The application of new techniques such as contrast-enhanced transesophageal echocardiography helps to assess the adequacy of cardioplegia distribution and, thus, myocardial protection during cardiopulmonary bypass, which has a significant influence on outcomes as well.

Advances in the stable isotope-mass spectrometric measurement of DNA synthesis and cell proliferation

Methods for measuring rates of DNA synthesis, and thus cell proliferation, in humans had not been available until recently. We (D. C. Macallan, C. A. Fullerton, R. A. Neese, K. Haddock, S. S. Park, and M. K. Hellerstein, 1998, Proc. Natl. Acad. Sci. USA 95, 708-713) recently developed a stable isotope-mass spectrometric technique for measuring DNA synthesis by labeling the deoxyribose (dR) moiety of purine deoxyribonucleotides through the de novo nucleotide synthesis pathway. The original analytic approach had limitations, however. Here, we describe technical improvements that increase yield, stability, sensitivity, and reproducibility of the method. The purine deoxyribonucleoside, deoxyadenosine (dA), is directly isolated from hydrolysates of DNA by using an LC18 SPE column. Two derivatives were developed for analyzing the dR moiety of dA alone (without the base), an aldonitrile-triacetate derivative, and a reduced pentose-tetraacetate (PTA) derivative. The PTA derivative in particular exhibited greater stability (no degradation after several weeks), greater GC/MS signal, and much less abundance sensitivity of isotope ratios (i.e., less dependence of mass isotopomer abundances on the amount of material injected into the mass spectrometer source), compared to previous derivatives of dA. The need for complex, multidimensional abundance corrected standard curves was thereby avoided. Using the PTA derivative, dR enrichments from DNA of fully turned over cells of rodents with 2H2O enrichments in body water of 2.2-2.8% were 9.0-9.5%, and less than 1.0 microg DNA (ca. 2 x 10(5) cells) was required for reproducible analyses. In summary, these methodologic advances allow measurement of stable isotope incorporation into DNA and calculation of cell proliferation and death rates in vivo in humans and experimental animals, with fewer cells, greater reproducibility, and less labor. Many applications of this approach can be envisioned.

Experimental estimate of energy accommodation coefficient at high temperatures

The energy accommodation coefficient (EAC), which is used to characterize gas-surface interactions, was experimentally estimated at high temperatures. A method utilizing laser irradiation to heat up nanoparticles that are generated in a flame was proposed. From the obtained dependence of particle temperature upon laser power, the EAC was derived to be approximately equal to 0.005, which agrees nicely with our recent rigorous theoretical result. It indicates that the efficiency of heat transfer between gas and particles is sufficiently small in high temperature system at large Knudsen numbers.

A numerical simulation of steady flow fields in a bypass tube

Steady flow in a complete by-pass tube was simulated numerically. The study was to consider a complete flow field, which included both the by-pass and the host tubes. The changes of the hemodynamics were investigated with three parameters: the inlet flow Reynolds number (Re), anastomotic angle (alpha) and the position of the occlusion in the host tube. The baseline flow field was set up with Re=200, alpha=45 degrees and the centered position of occlusion. The parametric study was then conducted on combination of Re=100, 200, 400, alpha=35 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees and three occlusion positions: left, center and right. It was found that in the baseline case, large slow/recirculation flows could be seen in the host tube both upstream and downstream of the occlusion. The separation points were on the opposite walls to the junctions. Recirculation zones were also found near the toe and in the proximal outer wall of the by-pass tube. Their sizes were about one diameter of the tube or smaller. In some cases, pairing vortices could be seen in the host tube upstream of the occlusion. The shear rate distribution associated with the flow fields was presented. The flow pattern obtained was agreeable to those observed experimentally by other investigators. The difference of the flow fields between a complete bypass and simple anastomosis was discussed. The present numerical code provides a preliminary simulation/design tool for bypass graft flows.

In vivo modulation of host response and macrophage behavior by polymer networks grafted with fibronectin-derived biomimetic oligopeptides: the role of RGD and PHSRN domains

Polymorphonuclear leukocytes, monocytes/macrophages, foreign body giant cells (FBGC), and lymphocytes are central in directing the host foreign body and inflammatory/immune reactions that impact material biostability, biocompatibility, and device efficacy. We employed the functional architecture of fibronectin to probe the mechanisms of protein-cell interaction in modulating leukocyte behavior. We demonstrated previously that the RGD and PHSRN domain of fibronectin and the spatial orientation between the motifs were crucial in regulating macrophage function in vitro. The current study delineates the role of RGD and PHSRN in modulating the host inflammatory response and macrophage behavior in vivo. Oligopeptides containing RGD and/or PHSRN domains were grafted onto a polyethyleneglycol-based substrate and subcutaneously cage implanted into rats. Peptide identity played a minimal role in modulating the host inflammatory response and adherent macrophage density. The RGD motif, either alone or at the terminal position with the PHSRN-containing flanking sequence, elicited a rapid macrophage fusion to form FBGCs at the early stage of implantation. Both the RGD motif and the PHSRN motif were important in mediating FBGC formation at the later implantation time. However, the PHSRN motif, specifically in the configuration of G3 RGDG6 PHSRNG, evoked a larger extent of FBGC coverage. Our results indicate the importance of RGD and PHSRN in modulating macrophage function in a time and orientation dependent fashion in vivo.

Syngeneic consecutive rat spleen transplantation bearing infantile testis

Seventy-seven Lewis adult rats received autologous testicular implants in the spleen. These spleens were retransplanted in a consecutive transplant fashion as we described earlier. Some were observed as long as 26 to 27 months. Although earlier splenic-testicular transplants showed benign granulosa cell tumors, some of the long-term follow-ups showed a seminoma-like transformation.

A novel reactivity of SeO(2) with 1,3-dienes: formation of syn 1,2- and 1,4-diols via a facile C-Se bond oxidation

[reaction: see text] A novel reaction between 1,3-dienes and selenium dioxide to give syn 1,2- and 1,4-diol cyclic selenites was studied in detail. This study indicates that an initial concerted [4 + 2] cycloaddition followed by a stereospecific carbon-selenium bond oxidation is involved in this unprecedented syn dihydroxy addition reaction mediated by selenium dioxide.

Cryopreservation of ovarian tissue: banking reproductive potential for the future

Cryopreservation of ovarian tissue is a technology that holds promise for banking reproductive potential for the future. It may be apropos for cancer survivors who have undergone treatment with sterility-inducing chemotherapy. Although there is some evidence suggesting cellular and molecular injury with the freezing and thawing process, there are examples in both animals and humans that transplantation of cryopreserved ovarian tissue can effectively bank reproductive potential for the future. This technology may ultimately have applications for in vitro fertilization, and preventing natural or iatrogenic menopause.

Aromatase inhibitors from Broussonetia papyrifera

Bioassay-guided fractionation of an ethyl acetate-soluble extract from the whole plants of Broussonetia papyrifera, using an in vitro aromatase inhibition assay, led to the isolation of five new active compounds, 5,7,2',4'-tetrahydroxy-3-geranylflavone (1), isogemichalcone C (8), 3'-[gamma-hydroxymethyl-(E)-gamma-methylallyl]-2,4,2',4'-tetrahydroxychalcone 11'-O-coumarate (9), demethylmoracin I (10), and (2S)-2',4'-dihydroxy-2' '-(1-hydroxy-1-methylethyl)dihydrofuro[2,3-h]flavanone (11), and 10 known (12-21) compounds which were also found to be active. Of these compounds, the most potent were 9 (IC(50) 0.5 microM), 11 (IC(50) 0.1 microM), isolicoflavonol (12, IC(50) 0.1 microM), and (2S)-abyssinone II (13, IC(50) 0.4 microM). Additionally, six new compounds, 5,7,3',4'-tetrahydroxy-6-geranylflavonol (2), 5,7,3',4'-tetrahydroxy-3-methoxy-6-geranylflavone (3), (2S)-7,4'-dihydroxy-3'-prenylflavan (4), 1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)propane (5), 1-(2,4-dihydroxy-3-prenylphenyl)-3-(4-hydroxyphenyl)propane (6), and 1-(4-hydroxy-2-methoxyphenyl)-3-(4-hydroxy-3-prenylphenyl)propane (7), were isolated and characterized, but proved to be inactive as aromatase inhibitors, as were an additional 21 known compounds. The structures of the new compounds (1-11) were elucidated by spectroscopic methods. Structure-activity relationships in the aromatase assay were determined for the benzofurans, biphenylpropanoids, coumarins, and various types of flavonoids (chalcones, flavans, flavanones, and flavones) obtained among a total of 42 constituents of B. papyrifera.

Anaesthesia in the United Nations Military Hospital, Dili, East Timor

An analysis of the anaesthesia caseload of the United Nations Military Hospital and its predecessors over the first 12 months of operation from September 1999 has been performed. Most patients were East Timorese civilians or Australian Military personnel. General anaesthesia using the ULCO Portable Field Anaesthesia Machine was most commonly administered.