Biomedical subjects

S-H Lee

Publications and source records attributed to S-H Lee.

65 records · Page 4Linked to original sources

PubMed2002

Emergent excitations in a geometrically frustrated magnet.

Frustrated systems are ubiquitous, and they are interesting because their behaviour is difficult to predict; frustration can lead to macroscopic degeneracies and qualitatively new states of matter. Magnetic systems offer good examples in the form of spin lattices, where all interactions between spins cannot be simultaneously satisfied. Here we report how unusual composite spin degrees of freedom can emerge from frustrated magnetic interactions in the cubic spinel ZnCr(2)O(4). Upon cooling, groups of six spins self-organize into weakly interacting antiferromagnetic loops, whose directors -- the unique direction along which the spins are aligned, parallel or antiparallel -- govern all low-temperature dynamics. The experimental evidence comes from a measurement of the magnetic form factor by inelastic neutron scattering; the data show that neutrons scatter from hexagonal spin clusters rather than individual spins. The hexagon directors are, to a first approximation, decoupled from each other, and hence their reorientations embody the long-sought local zero energy modes for the pyrochlore lattice.

Journal Article↗

PubMed2002

Freezing of a stripe liquid.

The existence of a stripe-liquid phase in a layered nickelate, La(1.725)Sr(0.275)NiO(4), is demonstrated through neutron scattering measurements. We show that incommensurate magnetic fluctuations evolve continuously through the charge-ordering temperature, although an abrupt decrease in the effective damping energy is observed on cooling through the transition. The energy and momentum dependence of the magnetic scattering are parametrized with a damped-harmonic-oscillator model describing overdamped spin waves in the antiferromagnetic domains defined instantaneously by charge stripes.

Journal Article↗

PubMed2002

Distribution of Aeromonas spp. as identified by 16S rDNA restriction fragment length polymorphism analysis in a trout farm.

AIMS: This study used restriction fragment length polymorphism (RFLP) with Aeromonas-specific primers to identify species of Aeromonas and to investigate their distribution in a trout farm and stream. METHODS AND RESULTS: In January, May, August and November 2000, presumptive Aeromonas species were recovered from a farm and a sedimentation pond in a fish farm and stream, and identified by PCR-RFLP analysis with Aeromonas-specific primers. The specificity of Aeromonas-specific primers and the suitability of PCR-RFLP analysis for identifying Aeromonas spp. were confirmed with fatty acid methyl esters (FAMEs) and 16S rDNA sequencing analyses, respectively. Levels of Aeromonas spp. sampled in May and August were higher than in January and November at all sampling sites. Aeromonas salmonicida was the dominant species in January and November, and the proportion of pathogenic species (Aer. hydrophila, Aer. caviae and Aer. veronii) increased in May and August. CONCLUSIONS: PCR-RFLP analysis with Aeromonas-specific primers is a rapid and reliable method for identifying widely distributed Aeromonas spp. from environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: To minimize human health risk, monitoring the levels and species composition of Aeromonas in fish farm is advisable.

Aeromonas↗

PubMed2002

Optimization of electroporation conditions for Mycobacterium avium.

Successful transformation and subsequent genetic manipulation of Mycobacterium avium requires suitable vectors, efficient transformation systems, and reliable selectable markers. A systematic analysis of the parameters involved in the transformation of M. avium was performed to optimize DNA transfer. Factors examined included the composition of the growth medium, growth medium additives, variations in washing of the bacteria prior to electroporation, and conditions of electroporation. Of the parameters assayed, the frequency of transformation (defined as the number of transformants per 10(6) transformed bacteria) showed the greatest increase with the addition of 1.5% glycine to the M. avium culture medium and the use of higher concentrations of plasmid DNA. The addition of 0.5 M sucrose to the growth medium and wash solution yielded a modest increase in transformation frequency, but more importantly afforded greater consistency of results between different batches of cells with no decrease in transformation yields following freezing and thawing. We also confirmed that gfp could be used as a selective marker for M. avium, even as a single copy integrant, and allowed for rapid discrimination between false and true transformants. Using this protocol, we were able to transform nine of 11 clinical strains of M. avium.

Culture Media↗

PubMedDate not supplied

Hematuria from left internal pudendal and obturator arterial bleeding following sexual intercourse.

Bladder tamponade is an uncommon clinical symptom among men who experience suffering related to sexual intercourse. The authors report on a 46-year-old man with this symptom 4-5 years before hospitalization. Angiography confirmed the presence of left pudendal and obturator arterial bleeding, and embolotherapy of the internal pudendal and obturator arteries was performed. There was no mortality, or limb loss or loss of sexual potency at follow-up.

Arteries↗

PubMedDate not supplied

Probability based diagnostic biopsy specimens as predictors of tumor grade and stage found.

The Gleason score of prostatic adenocarcinoma in biopsy specimens was compared with the Gleason score of corresponding radical prostatectomy specimens from 78 patients with localized prostate cancer. Grading errors were found to be significant for well-differentiated (Gleason score 2-4) tumors. The accuracy was 6 (23%) for Gleason scores of 2-4 on needle biopsy. All of the Gleason scores of 8-10 on needle biopsy were graded correctly. When the preoperative Gleason score was <7, 20 (37%) patients had organ-confined lesions, while when preoperative Gleason score > or = 7, 5 (21%) patients were confined to the prostate. Discrepancies between the Gleason score of the biopsy material and prostatectomy specimens were larger for biopsy specimens with low Gleason scores than for biopsy specimens with high Gleason scores. Large differences existed between the Gleason histologic scores of the biopsy and prostatectomy specimens when only a single microscopic focus of the tumor in the biopsy specimen is low grade. Consequently, when tumor grade influences the clinical management of prostate cancer, patients with limited biopsy material, provided this material is not poorly differentiated, should probably undergo repeated biopsy to reduce the likihood of tumor sampling error. This awareness influences treatment policy, particularly for the watchful waiting criteria of prostate cancer.

Adenocarcinoma↗

PubMedDate not supplied

Complications following combined transrectal ultrasound-guided prostate needle biopsies and transurethral resection of the prostate.

In order to evaluate safety and morbidity aspects of additional systematic prostate biopsies, we have conducted a retrospective review of patients who had undergone transurethral resection of the prostate (TUR-P) combined with additional systemic prostate needle biopsies at the Chang Gung Memorial Hospital. To this end, the records of 80 men presenting consecutively at our institution between February 2001 and January 2004 inclusively were examined. These 80 individuals included patients experiencing obstructive voiding symptoms and those featuring suspicious screening parameters, all of whom were to undergo transurethral resection of the prostate for symptomatic benign prostatic hyperplasia (BPH), all procedures being performed by a single surgeon. A total of 20 (25%) specimens were found to be positive for prostate cancer. Cancer was detected in the transrectal prostate biopsy specimen of 16 of 57 men (28%) who had not undergone a previous prostate biopsy, and for four of 23 (17%) who had undergone at least one previous (benign) biopsy. Mild complications associated with transurethral prostrate resection, such as hematuria and hemospermia, were reported frequently, featuring rates of 10% and 2.5%, respectively; more severe complications being noted far less frequently. Fever, usually of a low grade, was observed post-operatively for six (7.5%) patients, but a prompt return to normal temperature following antibiotic treatment for one day was revealed. Four (5%) patients remained admitted to the hospital for a prolonged period following surgery. A review of the literature concerning transrectal biopsies and TUR-P has shown that surgery-associated complication rates are slightly lower than was the case for our study. Additional systematic prostate biopsies for patients undergoing TUR-P would appear to be a relatively safe treatment procedure. Identification of risk factors for post-surgery complications might further improve the safety of the screening procedure.

Aged↗

PubMedDate not supplied

Malignant phyllodes tumor of the prostate.

This is a report of a 70-year-old man with malignant phyllodes tumor of prostate. The retropubic prostatectomy was done. The stroma of the tumor was cellular and composed of elongated cells with spindle shaped nuclei and fragmented bizarre giant cells. After recovery from surgery, prophylatic radiotherapy was given over 2 months. A case report of a patient treated at our medical center and a review of the literature was done.

Adenocarcinoma↗

PubMedDate not supplied

EBV-associated haemophagocytic syndrome in a patient with Behçet's disease.

We present a case of Epstein-Barr virus (EBV)-associated haemophagocytic syndrome in a patient with Behçet's disease. A 43-year-old man, who had been receiving treatment under the diagnosis of Behçet's disease for recurrent oral ulcers, genital ulcer, ileal ulcer, and arthritis, had been admitted for fever, headache, and nausea developed 3 days ago. Laboratory data showed pancytopaenia, an increase in liver enzymes, lactate dehydrogenase (LDH) and ferritin. Haemophagocytic syndrome was diagnosed from histiocytosis and haemophagocytosis by macrophages, shown in the bone marrow aspiration and biopsy, and in situ hybridization for EBV showed a positive finding. The patient recovered rapidly after steroid therapy. This is the first report of EBV-associated haemophagocytic syndrome developed in a patient with Behçet's disease.

Adult↗

PubMedDate not supplied

Minilaparotomy radical retropubic prostatectomy for prostate cancer.

Radical prostatectomy is still the gold standard for treating patients with clinically localized cancer. A total of 33 consecutive patients underwent minilaparotomy radical prostatectomy by a single surgeon. The minilaparotomy radical retropubic prostatectomy was performed via an eight-centimeter lower midline incision and a Book Walter retractor for surgical assistance. Mean patient age was 65 years (range 47 to 74). Tumor stages were observed as 12.1% of total for T1c, 21.2% for T2a, 45.5% for T2b, 6% for T3a and 15.2% for T3b. Satisfactory continence was achieved in 80% of the patients. 85% of patients revealed a prostate-specific antigen at a serum concentration of less than 0.2 ng/ml. Minilaparotomy radical retropubic prostatectomy compares favorably with standard radical retropubic prostatectomy.

Blood Loss, Surgical↗

PubMedDate not supplied

Profiling of differentially expressed genes in human uterine leiomyomas.

Uterine leiomyomas are very common benign tumors resulting in clinically serious gynecological problems in women of reproductive age. Approximately, 1% of leiomyosarcoma was reported to arise in a preexisting leiomyoma. However, the molecular basis of these tumors is poorly understood. To understand the molecular changes during leiomyoma development, we profiled differentially expressed genes in ten paired leiomyoma and normal myometrial tissues using cDNA microarray chip analysis. We identified 67 genes (27 overexpressed and 40 underexpressed) which were scored as differentially expressed at least twofold in at least eight of ten patients. Eighteen of 67 genes have been already reported to be differentially expressed without their established functions in uterine leiomyoma and others have never been reported. Subsequently, the relative expression levels of representative genes from identified 67 genes were confirmed by reverse-transcriptase polymerase chain reaction and immunohistochemistry and were found to be consistent with the microarray data. This study could provide a new insight into the understanding of leiomyoma and leiomyosarcoma.

Adult↗