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Biomedical subjects

E Meng

Publications and source records attributed to E Meng.

8 recordsLinked to original sources
PubMed2004

Congenital penile curvature: long-term results of operative treatment using the plication procedure.

AIM: To determine the long-term outcome, effectiveness and patient satisfaction of congenital penile curvature correction by plication of tunica albuginea. METHODS: From January 1992 to January 2002, 106 young patients underwent surgical correction of congenital penile curvature by corporeal plication. Indications for operation were difficult or impossible vaginal penetration and cosmetic problems. The technique of corporeal plication consists of placing longitudinal plication sutures of 2-zero braided polyester on the convex side of the curvature until the curvature is corrected when erection is artificially induced. Results of this procedure were obtained by retrospective chart reviews and questionnaires via mail. Long-term follow-up ranged from 11 to 132 (mean 69.3) months and data were available for 68 patients. RESULTS: Penile straightening was excellent in 62 patients (91 %) and good with less than 15 degree of residual curvature in 6 patients (9 %). Sixty-seven patients reported no change in erectile rigidity or maintenance postoperatively, while 1 described early detumescence. Shortening of the penis without functional problems was noted by 26 patients (38 %). Thirty-Five patients (51 %) reported feeling palpable indurations (suture knots) on the penis. Temporary numbness of glans penis was described in 3 patients. Overall, 60 patients were very satisfied, 6 satisfied, 2 unsatisfied. CONCLUSION: Corporeal plication is an effective and durable procedure with a high rate of patient satisfaction.

Adolescent↗
PubMed2001

Mutant G protein alpha subunit activated by Gbeta gamma: a model for receptor activation?

How receptors catalyze exchange of GTP for GDP bound to the Galpha subunit of trimeric G proteins is not known. One proposal is that the receptor uses the G protein's betagamma heterodimer as a lever, tilting it to pull open the guanine nucleotide binding pocket of Galpha. To test this possibility, we designed a mutant Galpha that would bind to betagamma in the tilted conformation. To do so, we excised a helical turn (four residues) from the N-terminal region of alpha(s), the alpha subunit of G(S), the stimulatory regulator of adenylyl cyclase. In the presence, but not in the absence, of transiently expressed beta(1) and gamma(2), this mutant (alpha(s)Delta), markedly stimulated cAMP accumulation. This effect depended on the ability of the coexpressed beta protein to interact normally with the lip of the nucleotide binding pocket of alpha(s)Delta. We substituted alanine for an aspartate in beta(1) that binds to a lysine (K206) in the lip of the alpha subunit's nucleotide binding pocket. Coexpressed with alpha(s)Delta and gamma(2), this mutant, beta(1)-D228A, elevated cAMP much less than did beta(1)-wild type; it did bind to alpha(s)Delta normally, however, as indicated by its unimpaired ability to target alpha(s)Delta to the plasma membrane. We conclude that betagamma can activate alpha(s) and that this effect probably involves both a tilt of betagamma relative to alpha(s) and interaction of beta with the lip of the nucleotide binding pocket. We speculate that receptors use a similar mechanism to activate trimeric G proteins.

Amino Acid Sequence↗
PubMed2001

Silicon couplers for microfluidic applications.

Several types of silicon fluidic coupler have been designed, fabricated, and tested to facilitate external connections to MEMS (microelectromechanical systems) fluidic devices. By using both bulk micromachining and DRIE (deep reactive ion-etching) techniques, couplers of different geometry have been produced for use with any standard MEMS fluidic port. In addition, couplers are easily modified to accommodate any arbitrary fluidic port geometry. For ease of use, these couplers interface with PEEK (polyetheretherketone) and fused-silica capillary tubing, both of which are commonly used in HPLC (high-performance liquid chromatography) systems and are supported by a wide range of plumbing products. Coupler performance was evaluated and an operating range of at least 0-8,963 kPa (0-1,300 psig) is attainable.

Journal Article↗
PubMed1993

Structure of a non-peptide inhibitor complexed with HIV-1 protease. Developing a cycle of structure-based drug design.

A stable, non-peptide inhibitor of the protease from type 1 human immunodeficiency virus has been developed, and the stereochemistry of binding defined through crystallographic three-dimensional structure determination. The initial compound, haloperidol, was discovered through computational screening of the Cambridge Structural Database using a shape complementarity algorithm. The subsequent modification is a non-peptidic lateral lead, which belongs to a family of compounds with well characterized pharmacological properties. This thioketal derivative of haloperidol and a halide counterion are bound within the enzyme active site in a mode distinct from the observed for peptide-based inhibitors. A variant of the protease cocrystallized with this inhibitor shows binding in the manner predicted during the initial computer-based search. The structures provide the context for subsequent synthetic modifications of the inhibitor.

Binding Sites↗
PubMedDate not supplied

Value of prostate-specific antigen in the staging of Taiwanese patients with newly diagnosed prostate cancer.

Records of 71 patients diagnosed with prostate cancer were reviewed retrospectively regarding clinical stage, prostate-specific antigen (PSA), Gleason score, CT scan of pelvis, bone scan, and pelvic lymph node dissection. Fourteen patients had pelvic lymphadenopathy based on the CT scan. Of these, no patient had a PSA level <4 ng/mL, 1 patient had a PSA level between 4 and 10 ng/mL, and 3 had a PSA level between 10 and 20 ng/mL. Twelve of 13 patients with positive bone scan results had a PSA level >20 ng/mL, and 1 patient had a PSA level between 10 and 20 ng/mL. PSA can be cost-effective in selecting and identifying appropriate staging for patients with newly diagnosed prostate cancer. CT scans are not indicated in men with clinical localized prostate cancer when PSA levels are < or =10 ng/mL. Bone scan is not required for staging asymptomatic men with PSA levels of < or =20 ng/mL. Pelvic lymphadenectomy for localized prostate cancer may not be necessary if PSA levels is < or =20 ng/mL and Gleason score is < or =5.

Adenocarcinoma↗
PubMedDate not supplied

Epidermoid cysts of the testes in Taiwanese men.

Epidermoid cyst is a rare benign tumor of the testes. The records from the last 20 years of Taiwanese patients in whom a testicular tumor was diagnosed were reviewed retrospectively. Patients with a confirmed epidermoid cyst of testis were evaluated for age, clinical assessment and follow-up. Among a total 146 testicular tumors, 28 (19%) patients had a benign tumor including 15 patients (10%; mean age 23 years, range 17-32 years) with an epidermoid cyst diagnosed pathologically. Pre-operative suspicion of the benign nature of the lesions was supported by testicular ultrasonography in 11 patients. Seven patients underwent magnetic resonance imaging after which benign epidermoid cyst was impressed in five patients. A testicular-sparing operation was performed in 12 patients after frozen sections confirmed the diagnosis. Three patients were treated by radical orchiectomy. There was no relapse after a median follow-up of 42 months (range, 2-82 months). Ultrasonography and magnetic resonance imaging of the scrotum may allow the diagnosis of epidermoid cyst of the testes to be made pre-operatively. The absence of relapse in these patients further supports the use of organ sparing surgery in these young men.

Adolescent↗
PubMedDate not supplied

Penile blunt trauma induced veno-occlusive erectile dysfunction.

Blunt trauma to the pelvic or perineal region of the corpora cavernosa is a risk factor for the subsequent development of persistent erectile dysfunction. The hemodynamic investigation of the integrity of the veno-occlusive mechanism has been rare in cases of traumatic impotence. We present two young men with erectile dysfunction following blunt penile or perineal trauma. Combined intracavernous injection and stimulation test, color duplex ultrasonography, and pharmacologic cavernosometry and cavernosography revealed normal arterial velocity and pulsation without cavernosal arterial fistula, but severe venous occlusion and site-specific abnormal veins were noted in both patients. They received penile vein ligation procedure and resulted in near-completely normal erectile function after a four-year followup. Penile venous ligation, especially on the site-specific veins, is still the choice of treatment for the trauma-induced penile veno-occlusive erectile dysfunction, and the result is satisfactory.

Humans↗