Enhancing Annular Fissures and High-Intensity Zones: Pain, Internal Derangement, and Anesthetic Response at Provocation Lumbar Discography.

BACKGROUND AND PURPOSE: A high-intensity zone identified on preprocedural MR imaging is known to correlate with pain at provocation lumbar discography. The correlation between enhancing annular fissures and pain at provocation lumbar discography has not been comprehensively evaluated. The purpose of this study was to assess the pain response and imaging features at enhancing annular fissure nonoperated disc levels identified on preprocedural MR imaging with comparison with the high-intensity zone and nonenhancing disc levels in patients referred for provocation lumbar discography. MATERIALS AND METHODS: One-hundred nonoperated discs in 44 patients were retrospectively evaluated for an enhancing annular fissure on sagittal postcontrast T1-weighted pre-discogram MR imaging. Enhancing annular fissure discs were graded on the sagittal T2-weighted sequence (Grade 4: like CSF to Grade 1: negative/barely visible) for high-intensity-zone conspicuity. High-intensity-zone detection was performed independently. In the primary assessment, enhancing annular fissure and high-intensity zones were associated with pain response at provocation lumbar discography. Additional analysis included intradiscal anesthetic response and postdiscogram CT appearance. RESULTS: Thirty-nine discs demonstrated an enhancing annular fissure, with 23/39 demonstrating a high-intensity zone. The presence of a high-intensity zone predicted severe pain (concordant + nonconcordant; P = .005, sensitivity of 40%, specificity of 94%) and concordant pain (P = .007, sensitivity of 39%, specificity of 86%) at provocation lumbar discography. Enhancing annular fissures without a detected high-intensity zone were more frequently observed among severely painful (50%) and concordant (36%) discs than among discs negative for pain (9%; P = .01). This finding resulted in a substantially greater overall sensitivity of enhancing annular fissures for severe (P < .001, 64%) and concordant pain (P = .008, 61%), significantly improving the overall predictive ability of a high-intensity zone alone. A high-intensity zone went undetected in 9/11 Grade 1 disc levels with concordant pain present in 7/9. CONCLUSIONS: Consideration of enhancing annular fissures on preprocedural MR imaging substantially improves the prediction of severe/concordant pain in provocation lumbar discography.

Image-guided percutaneous disc sampling: impact of antecedent antibiotics on yield.

AIM: To evaluate the effect of antecedent antimicrobial therapy on diagnostic yield from percutaneous image-guided disc-space sampling. MATERIALS AND METHODS: A retrospective review of the electronic health records of all patients who underwent image-guided percutaneous sampling procedures for suspected discitis/osteomyelitis over a 5-year period was performed. One hundred and twenty-four patients were identified. Demographics, medical history, and culture results were recorded as well as duration of presenting symptoms and whether antecedent antibiotic therapy had been administered. RESULTS: Of the 124 patients identified who underwent image-guided percutaneous disc-space sampling, 73 had received antecedent antibiotic treatment compared with 51 who had not. The overall positive culture rate for the present study population was 24% (n=30). The positive culture rate from patients previously on antibiotics was 21% (n=15) compared with 29% (n=15) for patients who had not received prior antibiotic treatment, which is not statistically significant (p=0.26). Eighty-six percent (n=63) of patients who had antecedent antibiotics received treatment for 4 or more days prior to their procedure, whereas 14% (n=10) received treatment for 1-3 days prior to their procedure. The difference in culture positivity rate between these two groups was not statistically significant (p=0.43). Culture results necessitated a change in antibiotic therapy in a third of the patients who had received antecedent antibiotic therapy. CONCLUSION: Antecedent antibiotic therapy, regardless of duration, did not result in significantly diminished diagnostic yield from percutaneous sampling for suspected discitis/osteomyelitis. The present results suggest that percutaneous biopsy may nonetheless yield positive diagnostic information despite prior antimicrobial therapy. If the diagnostic information may impact choice of therapeutic regimen, percutaneous biopsy should still be considered in cases where there is a history of prior antimicrobial therapy.

Long-term vital sign measurement using a non-contact vital sign sensor inside an office cubicle setting.

Heart and respiration rates can be wirelessly measured by extracting the phase shift caused by the periodic displacement of a patient's chest wall. We have developed a phased-array Doppler-based non-contact vital sign (NCVS) sensor capable of long-term vital signs monitoring using an automatic patient tracking and movement detection algorithm. Our NCVS sensor achieves non-contact heart rate monitoring with accuracies of over 90% (i.e, within ±5 Beats-Per-Minute vs. a reference sensor) across a large number of data points collected over various days of the week inside a typical office cubicle setting at a distance of 1.5 meters.

Accurate and continuous non-contact vital signs monitoring using phased array antennas in a clutter-free anechoic chamber.

Continuous and accurate monitoring of human vital signs is an important part of the healthcare industry, as it is the basic means by which the clinicians can determine the instantaneous status of their patients. Doppler-based noncontact vital signs (NCVS) sensor systems can monitor the heart and respiration rates without touching the patient, but it has been observed that that the accuracy of these NCVS sensors can be diminished by reflections from background clutters in the measurement environment, and that high directivity antennas can increase the sensing accuracy. Therefore, this work explores a NCVS sensor with continuous data taken inside an anechoic chamber where the background cluttering is negligible. In addition, a high directivity custom-made beam-steerable phased array antenna system is used to improve the performance and functionality of the 2.4GHz NCVS sensor we have built. We believe this work is the 1st systematic study using Doppler-based phased array systems for NCVS sensing performed in a clutter-free anechoic chamber.

Investigation of magnetic properties and microstructure of ultrathin Co films grown on Si(111)- 7 x 7 surface.

Magnetic properties and growth mechanism of ultrathin Co films on Si(111)-7 x 7 surface have been studied by using both surface magneto-optic Kerr effect (SMOKE) and scanning tunneling microscopy (STM), respectively. STM results show that the growth mechanism of ultrathin Co films on Si(111)-7 x 7 surface at room temperature belongs to Stranski-Krastanov (SK) growth mode. Due to formation of CoSi2 layer, no magnetic signal could be detected by SMOKE for 1-4 ML Co deposited on Si(111) surface. Because of rougher surface, both longitudinal and perpendicular magnetic anisotropy configuration appear for 4.2-10 ML Co/Si(111) films. When the Co thickness is increased to 10 ML, only longitudinal anisotropy configuration is found, resulting from the contribution to the volume anisotropy. Furthermore, in-plane coercivity increases with Co coverage because of enhancement of ferromagnetic coupling with Co thickness, out-of-plane coercivity increases with Co coverage due to the increment of demagnetized field, induced by the rougher Co surface and pinhole structures.

First Report of Powdery Mildew Caused by Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii on Papaya in Taiwan.

Powdery mildew can be found in most papaya (Carica papaya L.) fields during the winter and spring seasons in Taiwan. It usually causes severe yellowing of the leaf lamina and petiole and serious defoliation. Three types of powdery mildew fungi were isolated from papaya leaves in Chiayi City (23.28°N, 120.28°E) at the beginning of 2008. Conidia of the first one were single, globose, hyaline, and 24 to 36 × 14 to 18 µm (average 30.2 × 15.6 µm) without fibrosin bodies and with straight or occasionally flexuous conidiophores at the base. The second one had short pseudo-chains of two to four conidia which were ellipsoidal to ovoid, hyaline, and 24 to 40 × 12 to 16 µm (average 29.7 × 13.4 µm) without fibrosin bodies. The third type had chains of ellipsoidal conidia that were hyaline, 24 to 28 × 12 to 16 µm (average 26.3 × 14.4 µm) and contained fibrosin bodies. To confirm the identity of the three fungi, the internal transcribed spacer (ITS) region of rDNA was amplified using the primer pairs G1 (5'-TCC GTA GGT GAA CCT GCG GAA GGA T-3')/Ed2 (5'-CGC GTA GAG CCC ACG TCG GA-3'), G1 (5'-TCC GTA GGT GAA CCT GCG GAA GGA T-3')/On2 (5'-TGT GAT CCA TGT GAC TGG AA-3'), and S1 (5'-GGA TCA TTA CTG AGC GCG AGG CCC CG-3')/S2 (5'-CGC CGC CCT GGC GCG AGA TAC A-3'). The alignment of obtained sequences (GenBank Accession Nos. GU358452, 507 bp; GU358451, 580 bp; and GU358450, 455 bp) showed a sequence identity of 100, 99, and 99% with the ITS sequences of Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii (GenBank Accession Nos. FJ378880, EU909694, and GQ927254), respectively. On the basis of morphological characteristics and ITS sequence similarities, these fungi were identified as E. diffusa (Cooke & Peck) U. Braun & S. Takam., O. neolycopersici L. Kiss, and P. xanthii (Castagne) U. Braun & S. Takam., respectively (1,3). Single colonies on papaya leaves infected with powdery mildew were identified in the laboratory and maintained on papaya leaves as inoculum. Pathogenicity was confirmed through inoculations by gently pressing a single colony of each fungus onto leaves of healthy papaya seedlings (cv. Horng-Fe). Five seedlings were inoculated for each fungus and then covered with plastic bags for 2 days. Five noninoculated seedlings served as control. After inoculation, treated plants were maintained separately from the control in different rooms of a greenhouse at 25°C under natural daylight conditions. Seven days after inoculation, typical symptoms of powdery mildew were observed on inoculated plants, but not on noninoculated plants. The same species from diseased lesions following artificial inoculation with each fungus were identified with light microscopy. Papaya was previously described as a host to O. caricae Noack in many tropical and subtropical areas of the world including Taiwan (2). However E. cruciferarum, Golovinomyces cichoracearum, Oidiopsis sicula, O. caricae, O. caricae-papayae, O. caricicola, O. indicum, O. papayae, Ovulariopsis papayae, P. caricae-papayae, P. macularis, P. xanthii, and Streptopodium caricae were reported to infect papaya (4). To our knowledge, this is the first report of papaya powdery mildew caused by E. diffusa and O. neolycopersici in the world and the first report of the three fungi found on papaya in Taiwan. References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (2) H. S. Chien and H. L. Wang. J. Agric. Res. China 33:320, 1984. (3) L. Kiss et al. Mycol. Res. 105:684, 2001. (4) J. R. Liberato et al. Mycol. Res. 108:1185, 2004.

Comparison of the perforation rate for acute appendicitis between nationals and migrants in Taiwan, 1996-2001.

OBJECTIVE: Immigrant populations have grown rapidly in recent years in many countries. Immigrant-related healthcare issues have thus become more and more important. The aim of this study was to assess any possible disparity in access to care between migrants and nationals under the national health insurance (NHI) system in Taiwan. STUDY DESIGN: Retrospective population-based observational study. METHODS: National population-based data on patients aged ≥20 years in Taiwan under the NHI programme were studied. The frequency of use and expenditure on ambulatory care, inpatient care and emergency care were analysed separately. Ruptured appendicitis was also analysed as an outcome indicator for access to care. Logistic regression and two-part models were applied. RESULTS: Overall, migrants had a lower rate of healthcare utilization than nationals, and this gap remained consistent from 1996 to 2001. However, using ruptured appendicitis as the outcome indicator, no significant overall difference in access to care was found between nationals and migrants under the NHI programme in Taiwan (odds ratio 1.01, 95% confidence interval 0.93∼1.11). CONCLUSION: This study found that although migrants had a lower rate of healthcare utilization than nationals, their rate of adverse outcome was similar to nationals when they faced an acute, non-selective emergency condition such as appendicitis. The findings suggest that the use of more dimensional indicators may help to avoid possible misleading inferences on the variation in access to health care in Taiwan.

Screening markers of impaired glucose tolerance in the obese pediatric population.

BACKGROUND: With the epidemic of childhood obesity, it is crucial to devise a simple screening protocol to predict impaired glucose tolerance (IGT) or pre-diabetes. The oral glucose tolerance test (OGTT), which is the gold standard for the diagnosis of IGT, is impractical for screening purposes. This pilot study was designed to formulate a simple, sensitive algorithm to predict IGT using clinical and laboratory parameters. METHODS: Ethnicity, family history of diabetes, pubertal status, BMI z-score, blood pressure, lipids, hemoglobin A1c (HbA1c) and OGTT data were retrospectively collected from 209 overweight multi-ethnic subjects aged 3-21 years. Multivariate logistic regression was used to determine independent predictors of IGT. RESULTS: HbA1c was the only significant predictor of IGT (p = 0.001), whereas fasting glucose was not. A cut-off of 5.5% had the best combined sensitivity (85.7%) and specificity (56.9%) with an odds ratio of 7.9 of having IGT when HbA1c is > or =5.5%. The remaining clinical parameters were not significant predictors of IGT. CONCLUSION: While fasting blood glucose does not seem to be a predictor of IGT, we propose that HbA1c > or =5.5% can be used as a screening test to assess the risk of IGT and to determine who should undergo diagnostic OGTT. Large prospective studies validating our findings are warranted.

Initial experience in using continuous arterial spin-labeled MR imaging for early detection of Alzheimer disease.

BACKGROUND AND PURPOSE: MR imaging of the brain has significant potential in the early detection of neurodegenerative disorders such as AD. The purpose of this work was to determine if perfusion MR imaging can be used to separate AD from normal cognition in individual subjects. We investigated the diagnostic utility of perfusion MR imaging for early detection of AD compared with structural imaging. MATERIALS AND METHODS: Data were analyzed from 32 participants in the institutional review board-approved CHS-CS: 19 cognitively healthy individuals and 13 with clinically adjudicated AD. All subjects underwent structural T1-weighted SGPR and CASL MR imaging. Four readers with varying experience separately rated each CASL and SPGR scan finding as normal or abnormal on the basis of standardized qualitative diagnostic criteria for observed perfusion abnormalities on CASL or volume loss on SPGR and rated the confidence in their evaluation. RESULTS: Inter-rater reliability was superior in CASL (kappa = 0.7 in experienced readers) compared with SPGR (kappa = 0.17). CASL MR imaging had the highest sensitivity (85%) and accuracy (70%). Frontal lobe CASL findings increased sensitivity to 88% and accuracy to 79%. Fifty-seven percent of false-positive readings with CASL were in controls with cognitive decline or instability within 5 years. Three of the 4 readers revealed a statistically significant relationship between confidence and correct classification when using CASL. CONCLUSIONS: Readers were able to separate individuals with mild AD from those with normal cognition with high sensitivity by using CASL but not volumetric MR imaging. This initial experience suggests that CASL MR imaging may be a useful technique for detecting AD.

First Report of Anthracnose on Cucurbitaceous Crops Caused by Glomerella magna in Taiwan.

During the summer and fall of 2006, leaf anthracnose samples were collected from fields of cucumber (Cucumis sativus L.), calabash gourd (Lagenaria siceraria (Molina) Standley), and luffa (Luffa cylindrica (L.) M. Roem.) in southern Taiwan. On cucumber leaves, spots start as water-soaked areas and expand into brown spots. Leaf lesions on calabash gourd and luffa begin as water soaked and then become light brown-to-reddish spots. Centers of lesions sometimes fall out; giving infected leaves a shot-hole appearance. Small pieces (approximately 2 × 2 mm) of diseased leaf tissue from margins of individual lesions were surface disinfected in 1% sodium hypochlorite solution for 1 min, rinsed in sterile water, plated on water agar, and incubated at 25°C. After 4 days, mycelium was isolated, transferred to potato dextrose agar (PDA), and then incubated at 25°C in a 12-h light/darkness regimen. Fast-growing colonies on PDA were white to orange or pink with abundant acervuli but no perithecium. One-celled conidia were ovoid to oblong and 12 to 20 × 4 to 6 (15.9 × 5.0) µm. The morphological traits were identical to those of Colletotrichum magna (teleomorph Glomerella magna Jenkins & Winstead) and clearly distinct from those of C. orbiculare (Berk. & Mont.) Arx (synonym C. lagenarium (Pass.) Ellis & Halst. (conidia were mostly oblong, measuring 7 to 11 × 2 to 6 [9.3 × 4.2] µm, with slow-growing gray colonies) (2,3). Koch's postulates were performed to verify that the isolates were capable of causing anthracnose on cucurbitaceous crops. Pathogenicity tests were conducted in the greenhouse at 25°C under natural daylight conditions. Isolate C0604 was grown on PDA for 14 days and a spore suspension was made (106 spores/ml). Three 14-day-old seedlings at the two- to three-leaf stage of muskmelon (Cucumis melo L. var. reticulatus Naud., cv. Sapphire), squash (Cucurbita moschata Duch., cv. Achen), calabash gourd (cv. Huapu), and luffa (cv. 623) were sprayed with the spore suspension and then covered with plastic bags. Control treatments were sprayed with sterile water. After 2 days, the bags were removed. Typical anthracnose symptoms developed on all inoculated seedlings 7 days after inoculation. G. magna was reisolated from inoculated leaves following the protocol used for the original isolation. Control seedlings developed no symptoms. To confirm the identity of the fungus, PCR amplification and DNA sequencing of the internal transcribed spacer 1 (ITS1)-5.8S-ITS2 of rRNA gene of the isolate C0604 was performed by using ITS1/ITS4 as the PCR and sequencing primers. Sequence analysis of the 558-bp PCR product (GenBank Accession No. GU358453) showed 100% identity to the rRNA sequence of G. magna (GenBank Accession No. DQ003103) (1). PCR amplification of the ITS region was also carried out using species-specific primer GmF (5'- GTG AAC ATA CCT CAA ACG TTG CC -3')/GmR (5'- GGA GGG TCC GCC ACT GTA TTT CG -3') designed in this study. A DNA fragment of approximately 378 bp was amplified from nine isolates of G. magna, whereas no amplification products were obtained from reference cultures of C. gloeosporioides (Penz.) Penz. & Sacc. and C. orbiculare. To our knowledge, this is the first report of G. magna causing anthracnose on cucurbitaceous crops in Taiwan. References: (1) M. Du et al. Mycologia 97:641, 2005. (2) S. F. Jenkins, Jr. and N. N. Winstead. Phytopathology 54:452, 1964. (3) T. A. Zitter et al., eds. Compendium of Cucurbit Diseases. The American Phytopathological Society, St. Paul, MN, 1996.

First Report of Papaya Scab Caused by Cladosporium cladosporioides in Taiwan.

In March of 2008, a leaf scab disease was observed in a papaya (Carica papaya L.) orchard at Guoshing, 24.03°N, 120.51°E, in Nantou County, Taiwan. Infected papayas developed symptoms of numerous, pale green, water-soaked areas, 0.5 to 1.5 mm. Infected leaves gradually turned white to gray on the upper surface and small, circular swellings were observed on the abaxial surface. Lesions may coalesce to cover more than 50% of the leaf, rendering them to fall prematurely. Lesions on the lower surface of the leaves were covered with olive-gray patches of mycelia and abundant conidia. Pieces (~2 × 2 mm) of diseased leaf tissue from margins of individual lesions were surface disinfected in 1% sodium hypochlorite solution for 1 min, rinsed in sterile water, plated on water agar, and incubated at 25°C. After 4 days, mycelium was isolated and transferred to potato dextrose agar (PDA). Five isolates (Cc-5 to Cc-9) were isolated and identified as Cladosporium cladosporioides (Fresen.) de Vries based on the velvety, olive-brown with almost black reverse colony color and dimensions and color of conidia and conidiophores (1). Conidia formed in long branched chains that readily disarticulate, single celled, elliptical to limoniform, 2 to 9 (4.6) × 2 to 3 (2.2) µm. Conidia were pale-to-olive brown and smooth to verruculose. Ramoconidia were 0 to 1 septate, 6 to 14 (9.4) × 2 to 4 (2.7) µm, smooth or sometimes minutely verruculose. Conidiophores were pale-to-olive brown, macro- and micronemateus, smooth or sometimes verruculose, 68 to 244 (141.7) × 3.2 to 4 (3.9) µm. To confirm the identity of the fungus, the internal transcribed spacer (ITS) 1 and 4 regions and mitochondrial small subunit (mtSSU) rDNA were sequenced (GenBank Accession Nos. EU935608 and FJ362555), which had 99% homology to the ITS and mtSSU rDNA of C. cladosporioides (GenBank Accession Nos. EU497957 and AY291273, respectively). Pathogenicity tests were conducted in the greenhouse at 25°C with natural daylight conditions. Fungal isolate Cc-6 was used; it was grown on PDA for 6 days and a spore suspension was made (106 spores/ml). Three papaya seedlings (cv. Horng-Fe) were sprayed with the spore suspension and covered with plastic bags. Control treatments were sprayed with sterile water. After 2 days, the bags were removed. Symptoms developed on all inoculated seedlings 4 days after inoculation. In all cases, the typical scab symptom, pale green, water-soaked areas on the lower leaf surface, were observed. C. cladosporioides was reisolated from inoculated leaves following the procedure used for the original isolation. Control seedlings developed no symptoms. The five isolates are being maintained at the DBST, NCYU, Taiwan. Previously, papaya scab reported in China was caused by C. cariciolum Corda (2), C. caricinum C. F. Zhang et P. K. Chi (3), and C. cladosporioides (4). To our knowledge, this is the first report of C. cladosporioides causing papaya scab in Taiwan. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, England, 1971. (2) H.-H. Peng and Z.-Y. Zhang. J. Yunnan Agric. Univ. 12:23, 1997. (3) C.-F. Zhang. Ph.D. thesis. South China Agricultural University, Guangzhou, P.R.C., 1995. (4) Z. Y. Zhang et al. Flora Fungorum Sinicorum 14:1, 2003.

Comparison of the association of age with the infection of Salmonella and Salmonella enterica Serovar Typhimurium in Pekin ducks and Roman geese.

Nontyphoid Salmonella have a broad host range in poultry and mammals, and serovar Typhimurium is a threat to public health. In this study, normal and sick ducks and geese were collected from 12 farms in Taiwan to investigate the age-associated infection of Salmonella and Salmonella Typhimurium in Roman geese (Anser anser domesticus) and Pekin ducks (Anas platyrhynchos domesticus). In normal birds, the prevalence of Salmonella differed between species, and with age [e.g., 1-wk group, 37.5% (30/80) for ducks and 5.2% (6/116) for goslings (P < 0.05) vs. 4-wk group, 1% (1/96) for ducks and 12.1% (21/174) for geese]. Salmonella Typhimurium was identified from the visceral organs of moribund young geese suffering with colibacillosis and riemerellosis isolated from 2 goose farms (farm A and B, respectively). At farm B, 22.9% (27/118) of 4-wk geese with diarrhea were Salmonella Typhimurium-positive compared with 4.6% (8/174) of 4-wk normal geese. All Salmonella Typhimurium strains except one harbored a 94.7-kb virulence plasmid. Subcutaneous injection of Salmonella Typhimurium isolate 91NGL1 resulted in different clinical signs and pathogenesis between ducks and geese. In addition, the mean infectivity dose ratios of ducks to geese were 3.2 and 85.0 for 4- and 12-d birds, respectively, suggesting that goslings were more susceptible to Salmonella Typhimurium and resistance to Salmonella Typhimurium increased with age, especially for ducks. Therefore, Salmonella Typhimurium infection should be more common in goose farms than in duck farms, especially in the younger birds.

First Report of Simplicillium lanosoniveum Causing Brown Spot on Salvinia auriculata and S. molesta in Taiwan.

Salvinia spp. are small, floating ferns that grow in long chains of two oval leaves and a root-like third leaf. S. natans (L.) All., a native floating fern distributed in paddy fields, ponds, and ditches in Taiwan, has become critically endangered. Another two exotic species, S. auriculata Aublet (eared salvinia) and S. molesta Mitchell (giant salvinia), are sold in increasing frequency at local flower markets and aquarium shops and pose a serious threat when they find their way into the natural environment. Brown spot of S. auriculata was found in a home aquarium in December 2006 in Chiayi, Taiwan. Symptoms of the disease included many, irregular, dark brown spots on both upper and lower leaf surfaces. Lesions on the upper surface of the leaves were covered with white patches of mycelia and abundant conidia. Small pieces (approximately 2 × 2 mm) of diseased leaf tissue from the margin of individual lesions were surface disinfected in 1% sodium hypochlorite solution for 1 min, rinsed in sterile water, plated on water agar, and incubated at 25°C. Six isolates of the fungus were then isolated and transferred to potato dextrose agar (PDA). Isolate Cs0701 was identified morphologically as Simplicillium lanosoniveum (van Beyma) Zare & W. Gams on the basis of morphology of asexual reproduction structures and rDNA sequence analysis (1). In culture, this fungus formed whitish-to-whitish yellow, pulvinate colonies with matted surfaces. The reverse side of cultures was yellow to light brown. Small, ovate to spherical, hyaline conidia, 2.2 to 3.0 × 1.6 to 2.0 µm (average 2.4 × 1.9 µm) were formed. To confirm the identity of the fungus, PCR amplification and DNA sequencing of the internal transcribed spacer (ITS1-5.8S-ITS2 rRNA gene cluster) was conducted on isolates Cs0701 and Cs0702. The sequence of the PCR product was compared with sequences of closely related species listed in the GenBank database. Except for a single nucleotide, the ITS sequence of both isolates (480 bp; GenBank Accession No. EU939525) was identical to the rRNA of Simplicillium lanosoniveum (GenBank Accession No. AJ292396). Koch's postulates were performed to confirm the pathogenicity of the fungus on S. auriculata and S. molesta. After 14 days of growth on PDA, a spore suspension of isolate Cs0701 (106 spores per ml) was sprayed onto approximately 5 and 10 g of healthy S. auriculata and S. molesta plants, respectively, floated in 500-ml beakers filled with 300 ml of tap water. All treatments, including controls misted with sterile water, were replicated three times. The beakers were covered with plastic bags and placed in a growth chamber maintained at 25°C with 12-h fluorescent light cycles. After 2 days, the bags were removed. Symptoms developed on all inoculated plants 4 days after inoculation. In all cases, typical brown spots were observed. Simplicillium lanosoniveum was reisolated from all surface-disinfested infected tissues. Control plants developed no symptoms. Six isolates of the fungus are being maintained at the Department of Microbiology and Immunology, National Chiayi University, Taiwan. To our knowledge, this is the first report of Simplicillium lanosoniveum causing brown spot of S. auriculata and S. molesta in Taiwan. Reference: (1) R. Zare and W. Gams. Nova Hedwigia 73:1, 2001.

Quantum dots for live cells, in vivo imaging, and diagnostics.

Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biological applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biology. Recent examples of their experimental use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-infrared emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.

Peptide-coated semiconductor nanocrystals for biomedical applications.

We have developed a new functionalization approach for semiconductor nanocrystals based on a single-step exchange of surface ligands with custom-designed peptides. This peptide-coating technique yield small, monodisperse and very stable water-soluble NCs that remain bright and photostable. We have used this approach on several types of core and core-shell NCs in the visible and near-infrared spectrum range and used fluorescence correlation spectroscopy for rapid assessment of the colloidal and photophysical properties of the resulting particles. This peptide coating strategy has several advantages: it yields probes that are immediately biocompatible; it is amenable to improvements of the different properties (solubilization, functionalization, etc) via rational design, parallel synthesis, or molecular evolution; it permits the combination of several functions on individual NCs. These functionalized NCs have been used for diverse biomedical applications. Two are discussed here: single-particle tracking of membrane receptor in live cells and combined fluorescence and PET imaging of targeted delivery in live animals.

Quantum dots for molecular imaging and cancer medicine.

Extract: The past few decades have witnessed technical advances that have introduced cell biologists and physicians to a new, dynamic, subcellular world where genes and gene products can be visualized to interact in space and time and in health and disease. The accelerating field of molecular imaging has been critically dependent on indicator probes which show when and where genetically or biochemically defined molecules, signals or processes appear, interact and disappear, with high spatial and temporal resolution in living cells and whole organisms. For example, the use of radionuclide tracers combined with 3-dimensional (3-D) imaging systems such as Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) are now helping clinicians to characterize the molecular status of tumors deep within patients. Other types of imaging probes rely on the bioluminescence and fluorescence of genetically encoded proteins (originally found in fireflies and jellyfish, respectively) or entirely synthetic fluorochromes, or a combination of both. New powerful biological fluorescence microscopes provide the ability to study single molecules within single cells. Multiphoton confocal microscopy has been developed to allow for the capturing of high-resolution, 3-D images of living tissues that have been tagged with highly specific fluorophores.

The design and synthesis of purine inhibitors of CDK2. III.

Cyclin-dependent kinases (CDKs) belong to a class of enzymes that control the ability of a cell to enter into and proceed through the cell division cycle. Using purine as a scaffold, we have synthesized a number of nanomolar inhibitors of CDK-2/cyclin E. In this report, the synthesis of a series of piperidine-substituted purine analogs will be presented, as well as some of their in vitro and in vivo biological effects.

Crystal structure of human cyclin-dependent kinase 2 in complex with the adenine-derived inhibitor H717.

Cyclin-dependent kinases (CDKs) are regulatory proteins of the eukaryotic cell cycle. They act after association with different cyclins, the concentrations of which vary throughout the progression of the cell cycle. As central mediators of cell growth, CDKs are potential targets for inhibitory molecules that would allow disruption of the cell cycle in order to evoke an antiproliferative effect and may therefore be useful as cancer therapeutics. We synthesized several inhibitory 2,6,9-trisubstituted purine derivatives and solved the crystal structure of one of these compounds, H717, in complex with human CDK2 at 2.6 A resolution. The orientation of the C2-p-diaminocyclohexyl portion of the inhibitor is strikingly different from those of similar moieties in other related inhibitor complexes. The N9-cyclopentyl ring fully occupies a space in the enzyme which is otherwise empty, while the C6-N-aminobenzyl substituent points out of the ATP-binding site. The structure provides a basis for the further development of more potent inhibitory drugs.

Lasting effects of transient postinoculation tenofovir [9-R-(2-Phosphonomethoxypropyl)adenine] treatment on SHIV(KU2) infection of rhesus macaques.

SHIV(KU2) replicates to high levels in inoculated macaques and reproducibly causes an acute depletion of CD4(+) T cells. We evaluated the ability of treatment with the antiretroviral drug 9-R-(2-phosphonomethoxypropyl)adenine (PMPA; tenofovir), begun 7 days postinoculation, to inhibit viral replication and associated pathogenesis. Highly productive infection (plasma viral RNA > 10(6) copy eq/mL) was present and CD4 depletion had started when treatment was initiated. PMPA treatment was associated with a rapid decline in plasma viral RNA to undetectable levels, with parallel decreases in the infectivity of plasma and infectious cells in PBMCs and CSF and stabilization of CD4(+)T-cell levels. Viral dynamics parameters were calculated for the initial phase of exponential viral replication and the treatment-related decline in plasma viremia. Following cessation of treatment after 12 weeks, plasma viral RNA was detectable intermittently at low levels, and spliced viral transcripts were detected in lymph nodes. Although treatment was begun after viral dissemination, high viremia, and CD4 decreases had occurred, following withdrawal of PMPA, CD4(+) T-cell counts normalized and stabilized in the normal range, despite persistent low-level infection. No PMPA-resistance mutations were detected. These results validate the similar viral replicative dynamics of SHIV(KU2) and HIV and SIV, and also underscore the potential for long-term modulation of viral replication patterns and clinical course by perturbation of primary infection.

HIV-1 drug resistance in newly infected individuals.

CONTEXT: There is concern that the widespread use of antiretroviral drugs to treat human immunodeficiency virus 1 (HIV-1) infection may result in the increased transmission of drug-resistant virus. OBJECTIVE: To determine the prevalence of drug resistance-conferring mutations and phenotypic resistance to antiretroviral agents in a cohort of individuals newly infected with HIV-1. DESIGN: Case series with genetic analyses of the HIV-1 plasma-derived pol gene using reverse transcriptase polymerase chain reaction followed by direct sequencing of polymerase chain reaction products. Phenotypic analysis was performed with a recombinant virus assay. SETTING AND PATIENTS: Eighty individuals referred, on average, 1.7 months after infection with HIV-1 to the Aaron Diamond AIDS Research Center between July 1995 and April 1999. Subjects were from large urban areas (65 from New York, NY; 11 from Los Angeles, Calif); 60 (75%) were white, and 75 (93.8%) were homosexual men. MAIN OUTCOME MEASURES: Prevalence of known resistance-conferring genotypes and reduced susceptibility to individual antiviral agents by phenotype. RESULTS: Thirteen individuals (16.3%) had genotypes associated with drug resistance to any antiretroviral agent. Virus with known resistance-conferring mutations to any nucleoside reverse transcriptase inhibitors was found in 10 individuals, to any nonnucleoside reverse transcriptase inhibitors in 6 subjects, and to any protease inhibitors in 2 cases. Multidrug-resistant virus was identified in 3 individuals (3.8%). Extensive polymorphism in the protease gene was identified. Interpretation of genotypes and phenotypes was concordant in 57 (85%) of the 67 cases in which both studies were performed. CONCLUSION: The prevalence of HIV-1 variants with known resistance-conferring genotypes to any antiretroviral agent in this cohort of 80 newly infected individuals is 16.3%. These data support expanded use of resistance testing in the setting of primary HIV-1 infection. Clinical trials should be initiated to establish whether therapy guided by resistance testing, compared with the use of empirical triple combination antiretroviral therapy, provides additional virological and immunological benefit when treating primary HIV-1 infection. Further efforts to expand the study of transmission of drug-resistant HIV-1 variants, particularly in cohorts with different epidemiological profiles, are indicated.