Detection of microorganisms using terahertz metamaterials.

Microorganisms such as fungi and bacteria cause many human diseases and therefore rapid and accurate identification of these substances is essential for effective treatment and prevention of further infections. In particular, contemporary microbial detection technique is limited by the low detection speed which usually extends over a couple of days. Here we demonstrate that metamaterials operating in the terahertz frequency range shows promising potential for use in fabricating the highly sensitive and selective microbial sensors that are capable of high-speed on-site detection of microorganisms in both ambient and aqueous environments. We were able to detect extremely small amounts of the microorganisms, because their sizes are on the same scale as the micro-gaps of the terahertz metamaterials. The resonant frequency shift of the metamaterials was investigated in terms of the number density and the dielectric constants of the microorganisms, which was successfully interpreted by the change in the effective dielectric constant of a gap area.

Risk of hepatitis B reactivation and the role of novel agents and stem-cell transplantation in multiple myeloma patients with hepatitis B virus (HBV) infection.

BACKGROUND: The purpose of the study is to analyse the prevalence of hepatitis B virus (HBV) infection and its incidence of reactivation among multiple myeloma (MM) patients treated in the era of novel therapy in an endemic Asian setting. PATIENTS AND METHODS: From 2000 to 2008, 273 patients with newly diagnosed MM were screened for the presence of hepatitis B virus surface antigen and HBV core antibody. HBV-infected patients were prospectively followed for reactivation with serial monitoring of serum alanine transferase and HBV DNA load. The patterns of HBV reactivation in relation to treatment received, exposure to high-dose therapy with autologous stem-cell transplantation (HDT/ASCT) and novel agents were studied. RESULTS: The prevalence of HBV infection was 5.5%. Three cases of HBV reactivation despite lamivudine prophylaxis were reported. Two patients reactivated 3-5 months after HDT/ASCT while receiving thalidomide maintenance and one reactivated 3 years after HDT/ASCT and shortly after bortezomib salvage therapy. Emergence of a mutant HBV strain was documented in one patient. CONCLUSIONS: Use of prophylaxis may reduce but will not preclude HBV reactivation. Highest risk occurs during immune reconstitution phase of HDT/ASCT. The role of immunomodulatory agents in HBV reactivation needs to be further elucidated. Separate HBV prophylaxis and surveillance guidelines ought to be developed for patients with MM.

Effects of a cGMP-specific phosphodiesterase inhibitor on expression of endothelial nitric oxide synthase and vascular endothelial growth factor in rats with cyclosporine-induced nephrotoxicity.

BACKGROUND: The mechanism of cyclosporine (CsA)-induced nephrotoxicity has been suggested to be vasoconstriction due to reduced nitric oxide (NO), providing tissue fibrosis by elevation of transforming growth factor beta and vascular endothelial growth factor (VEGF). In this study using a rat model of CsA-induced nephrotoxicity, we administered a phosphodiesterase-5 inhibitor to ameliorate the renal injury and alter the expression of endothelial No synthase (eNOS) and VEGF. METHODS: A right nephrectomy was performed in Sprague-Dawley rats (n = 30; 200-250 g, all male). The Ischemia group (n = 6) underwent ligation of the left renal artery for 45 minutes (IR) before observation for 28 days. After IR, the udenafil group (n = 6) was treated with 10 mg/kg drug orally, the CsA group (n = 6) received 15 mg/kg CsA injected subcutaneously and the CsA plus udenafil group (n = 6) received 15 mg/kg CsA injected subcutaneously together with the oral administration of 10 mg/kg udenafil. RESULTS: Administration of udenafil significantly decreased serum creatinine either alone (0.21 ± 0.04 mg/dL) or in combination with CsA (1.86 ± 0.35 mg/dL) versus the ischemia (0.85 ± 0.22 mg/dL) and the CsA alone (3. 10 ± 0.77 mg/dL) group. (P = .002; P = .002). Comparing the Hematoxylin-eosin staining of the ischemia (0.41 ± 0.09) and CsA (0.44 ± 0.08) groups showed a significantly decreased loss of nuclei in proximal tubules after the administration of udenafil (0.27 ± 0.05 [P = .004] and 0.26 ± 0.02 [P = .002] respectively). Immunohistochemical staining showed strong eNOS staining in the udenafil and CsA plus udenafil groups. Western blots for eNOS showed decreased expression in the CsA group and increased expression in the udenafil group. Western blots for VEGF revealed reduced expression only in the CsA plus udenafil group. eNOS mRNA was decreased in the CsA (0.017 ± 0.010) compared with the ischemia group (0.048 ± 0.015; P = .000). VEGF mRNA which was decreased in the CsA group (2.026 ± 1.109), showed greater tendency after administration of udenafil (0.440 ± 0.449) (P = .003). CONCLUSION: The phosphodiesterase inhibitor ameliorated renal injury in a rat model of CsA-induced nephrotoxicity, possibly related to increased eNOS and reduced VEGF expression.

Phenotypic variation in FAM83H-associated amelogenesis imperfecta.

FAM83H gene mutations are associated with autosomal-dominant hypocalcified amelogenesis imperfecta (ADHCAI), which is typically characterized by enamel having normal thickness and a markedly decreased mineral content. This study tested the hypothesis that there are phenotype and genotype associations in families with FAM83H-associated ADHCAI. Seven families segregating ADHCAI (147 individuals) were evaluated. Phenotyping included clinical, radiographic, histological, and biochemical studies, and genotyping was by mutational analysis. Multiple novel FAM83H mutations were identified, including two 2-bp-deletion mutations, the first non-nonsense mutations identified. Craniofacial deviation from normal was more prevalent in the affected individuals. Affected individuals having truncating FAMH3H mutations of 677 or fewer amino acids presented a generalized ADHCAI phenotype, while those having mutations capable of producing a protein of at least 694 amino acids had a unique and previously unreported phenotype affecting primarily the cervical enamel. This investigation shows that unique phenotypes are associated with specific FAM83H mutations.

Low-Power Testing of Losses in Millimeter-Wave Transmission Lines for High-Power Applications.

We report the measurement of small losses in transmission line (TL) components intended for high-power millimeter-wave applications. Measurements were made using two different low-power techniques: a coherent technique using a vector network analyzer (VNA) and an incoherent technique using a radiometer. The measured loss in a 140 GHz 12.7 mm diameter TL system, consisting of 1.7 m of circular corrugated waveguide and three miter bends, is dominated by the miter bend loss. The measured loss was 0.3±0.1 dB per miter bend using a VNA; and 0.22±0.1 dB per miter bend using a radiometer. Good agreement between the two measurement techniques implies that both are useful for measuring small losses. To verify the methodology, the VNA technique was employed to measure the extremely small transmission loss in a 170 GHz ITER prototype TL system consisting of three lengths of 1 m, 63.5 mm diameter, circular corrugated waveguide and two miter bends. The measured loss of 0.05±0.02 dB per miter bend may be compared with the theoretical loss of 0.027 dB per miter bend. These results suggest that low-power testing of TL losses, utilizing a small, simple TL system and a VNA, is a reliable method for evaluating performance of low-loss millimeter-wave TL components intended for use in high-power applications.

STD / AIDS -- the need for a global response.

PIP: While the HIV/AIDS epidemic continues to destroy lives throughout the world, sexually transmitted diseases (STDs) also remain a major public health problem. Both HIV/AIDS and STDs have a disproportionate impact on developing countries and are major deterrents to social and economic development. HIV/AIDS is more readily transmitted in the presence of ulcerative STDs, and behaviors that place individuals at risk of STDs also increase risk of HIV/AIDS. Effective management of STDs can be considered a major strategy in controlling the sexual transmission of HIV/AIDS. In order to control STDs in a given population, it is important to understand such aspects as how well a particular society can detect asymptomatic infection, how many people receive inadequate treatment, the effectiveness of STD management, the cost of drugs, and the success of partner notification. Because it is difficult to control STDS effectively, most health systems simply treat symptomatic disease. A new prevention approach must be developed that is centered on people and that will emphasize individual responsibility in making decisions about sexual behavior. Responsible behavior depends upon community support and education to acquire the knowledge and skills necessary to avoid risks. The public health package created by the World Health Organization for STD control includes promotion of safer sexual behavior (including condom use), provision of comprehensive case management, specific interventions for high-risk populations, promotion of appropriate health care-seeking behavior, case finding for syphilis during pregnancy, and prophylaxis of ophthalmia neonatorum. Governments and policymakers must ask whether they are doing enough to prevent and control the spread of STDs and HIV/AIDS.^ieng

Electromagnetic scattering of two-dimensional surface-relief dielectric gratings.

We employed the rigorous vector coupled-wave theory [J. Opt. Soc. Am. 73, 1105 (1983)] to analyze the electromagnetic scattering from two dimensional (2-D) surface-relief dielectric gratings. A shoot-back method was developed for the numerical solution of the resulting coupled differential equations. This method allowed numerical solutions to be found for grating structures of arbitrary profiles and relatively deep grooves. It was most suitable where the grating medium refractive index was not too large and where only a small number of propagating orders existed. Experiments confirmed the numerically predicted reflectivities for 2-D surface-relief dielectric sinusoidal gratings. Reflectivity measurements were made on 2-D sinusoidal gratings fabricated on photoresist and on polycarbonate. The grating periodicities were of the order of 3000 lines/mm such that only the zero-order diffracted waves were propagating in the incident region, and possibly a few forward orders in the transmission region. The embossing technique that was used for replicating the grating patterns from photoresist onto polycarbonate proved to be a feasible method for the production of such gratings.

[Effects of calcium ion on contractile response of guinea-pig gallbladder muscle strip to agonists].

The effects of calcium ion on the contractile response of gallbladder muscle strip (GBMS) in guinea pigs to acetylcholine, carbachol and caerulein were investigated by method of isotonic contraction and by RIA of cGMP and cAMP in the tissue. It was shown that the contractile response of GBMS to these agonists was stronger in Krebs solution than that in the calcium-free solution. In calcium-free solution, EDTA-zero calcium solution or verapamil-Krebs solution, the contractile response of GBMD was decreased to about 30% of the control (P less than 0.01). Verapamil significantly decreased carbachol induced enhancement of cGMP and cAMP of gallbladder tissue (P less than 0.01 or 0.05). The results suggest that both extra-and intra- cellular calcium take part in the contractile response of GBMS to agonists.

Performance of a fully automated program for measurement of left ventricular ejection fraction.

A fully automated program developed by us for measurement of left ventricular ejection fraction from equilibrium gated blood pool studies was evaluated in 130 additional patients. Both 6-min (130 studies) and 2-min (142 studies in 31 patients) gated blood pool studies were acquired and processed. The program successfully generated ejection fractions in 86% of the studies. These automatically generated ejection fractions were compared with ejection fractions derived from manually drawn regions of interest. When studies were acquired for 6-min with the patient at rest, the correlation between automated and manual ejection fractions was 0.92. When studies were acquired for 2-min, both at rest and during bicycle exercise, the correlation was 0.81. In 25 studies from patients who also underwent contrast ventriculography, the program successfully generated regions of interest in 22 (88%). The correlation between the ejection fraction determined by contrast ventriculography and the automatically generated radionuclide ejection fraction was 0.79.

Evaluation of a miniature CdTe detector for monitoring left ventricular function.

A miniature CdTe probe interfaced to a microcomputer was used to measure left ventricular ejection fraction (LVEF) in 25 patients. LVEF obtained with the CdTe module, in the beat-to-beat mode, or the integrated gated mode agreed well with LVEF obtained with a gamma camera (r = 0.80; r = 0.82 respectively). Similarly, LVEF by CdTe probe agreed with LVEF obtained by gated equilibrium studies performed with a computerized NaI probe. The CdTe probe can provide comparable measurement of LVEF at a fraction of the cost of a camera-computer system and, being small and lightweight, the CdTe probe is adaptable for monitoring patients in intensive care facilities.