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Biomedical subjects

E Gan

Publications and source records attributed to E Gan.

At least 19 recordsLinked to original sources
PubMed2000

Transrectal ultrasound-guided needle aspiration for prostatic abscesses: an alternative to transurethral drainage?

PURPOSE: Prostatic abscesses traditionally are drained transurethrally. Problems of this method include the risk of anesthesia, dissemination of bacteria, incomplete drainage of multiloculated or peripheral abscesses, and retrograde ejaculation, which may not be acceptable for young patients. Prostatic abscesses can be drained under transectal ultrasound (TRUS) guidance. Multiple, peripheral, or multiloculated abscesses are visualized. No anesthesia would be required. Repeat procedures can be performed easily with minimal morbidity. The risks of dissemination and retrograde ejaculation is negligible. MATERIALS AND METHODS: A standard TRUS probe and a 21-gauge Chiba needle are inserted through the biopsy guide into the abscesses. Five patients underwent the procedure. Four patients had a mean follow-up of 18 months. RESULTS: TRUS could visualize the abscess in all patients. Aspirate cultures corresponded to the urine culture except in one patient with sterile urine. Three had residual disease on repeat TRUS, but only two patients required repeat aspiration. All patients recovered and had no evidence of disease on follow-up. However, it was an average of 4 months before patients could be considered cured according to TRUS findings. Prostate volume decreased from a mean of 54 mL on diagnosis to 16 mL on follow-up. There was no hospital readmission or morbidity. CONCLUSIONS: TRUS needle aspiration for prostatic abscess is a feasible alternative to transurethral drainage. Repeat procedures may be required, but all patients recovered. There is minimal morbidity associated with the procedure; however, the recovery period may be longer.

Abscess↗
PubMed2000

Pitfalls in the diagnosis of prostate adenocarcinoma from holmium resection of the prostate.

PURPOSE: Holmium laser resection of the prostate (HoLRP) provides tissue for histologic analysis that was not possible using previous coagulative laser prostatectomies. It was assumed that these tissue specimens would yield the same histologic information as specimens obtained by transurethal resection of the prostate and would be adequate for diagnosis of cancer. However, tissue subjected to laser treatment may sustain thermal injury, resulting in artifactual change. The aim of this study was to define the histologic characteristics of prostate tissue after holmium laser prostatectomy and the influence of thermal change on diagnosis of malignancy. MATERIALS AND METHODS: All prostate tissue was examined after HoLRP. Examination included prostate-specific antigen (PSA) staining and immunostaining for high-molecular-weight cytokeratins. Histologic features are described. RESULTS: Thermal injury after HoLRP was more extensive than previously believed. Artifacts observed under low power consisted of glandular distortion and contraction with crowding. Higher magnification revealed clumping of the chromatin of the nucleus, resulting in hyperchromasia and irregularity of the nucleus and loss of polarity. These changes may be mistaken for malignant change. It will be difficult to detect malignancy in areas involved by thermal injury. When prostate cancer exists, grading of cancer will be affected by these artifacts. Uptake of immunohistochemical staining with PSA and high-molecular-weight cytokeratins is nonspecific in areas of injury, reducing their usefulness in these cases. CONCLUSIONS: Detection of malignancy may be compromised by thermal injury occurring after HoLRP. Preliminary preoperative transrectal ultrasound-guided biopsies may still be necessary for diagnosis of malignancy.

Adenocarcinoma↗
PubMed1999

ATP and other nucleotides stabilize the Rho-mRNA complex.

Transcription termination factor Rho from Escherichia coli is a protein that consists of a single 47 kDa protomeric unit that can form a hexameric structure. To determine whether active hexamers can form on an RNA by assembly of subunits, we measured the dependence of complex formation on the concentration of Rho protein in the presence and absence of various nucleotides and related the binding properties to association states determined from sedimentation properties. The results show that the presence of adenine nucleotides converts RNA binding from a multimeric process to a largely monomeric process and that the change correlates with the stabilization of multimers of Rho by the nucleotides. The experimental evidence also indicates that the hexameric form of Rho is stabilized slightly by binding to a transcript but that the protein on RNA is in equilibrium with nonhexameric forms. These results suggest that a Rho hexamer can form on a transcript by addition of subunits to a partial assembly, which means that the complex can consist of six subunits surrounding an RNA transcript as proposed in recent models for Rho action.

Adenine Nucleotides↗
PubMed1998

Repair of complex ureterovaginal and vesicovaginal fistulas with ileal cystoplasty and ureteric reimplantation into an antireflux ileal nipple valve--a case report.

We report a case of a 59-year-old woman with bilateral ureterovaginal and vesicovaginal fistulas after radical total hysterectomy and bilateral salphingo-oophorectomy who failed transvesical repair of the vesicovaginal fistula. The bladder was extensively scarred, half of which had to be excised. This was replaced with an ileal cystoplasty with an antireflux ileal nipple valve into which the ureters were reimplanted. Continuity of the urinary tract was re-established without a urinary diversion or stoma.

Female↗
PubMed1995

Use of prostate specific antigen (PSA) and transrectal ultrasound (TRUS) in the diagnosis of prostate cancer--a local experience.

Prostate specific antigen (PSA) and transrectal ultrasound (TRUS) are two new modalities added to improve our ability to diagnose prostate cancer at an early stage. We reviewed our own experience of 100 cancers among 579 men from August 1991 to October1994. The detection rate was 17.3%. Digital rectal examination (DRE) alone had a positive predictive value (PPV) of 39.9%. The PPV for PSA was 23%. The combination of PSA and DRE gave a PPV of 47.2%. TRUS had a PPV of 30.6%. Features of cancer on TRUS may be both hypoechoic or hyperechoic nodules which appeared to have almost equal proportions associated with cancer. The addition of age-specific ranges did not affect the PPV of PSA. The PPV of the combination of TRUS and DRE was 53%. With all 3 modalities combined, the PPV was 58.8%. An interesting finding from the study was the higher average PSA for benign and malignant disease in the local population and cases of acute retention of urine. There was a higher incidence of prostatitis and lower incidence of cancer in cases with retention of urine.

Adult↗
PubMed1990

Multi-laboratory evaluation of a scrub typhus diagnostic kit.

Scrub typhus is a major cause of febrile illness throughout the Asia-Pacific region. It is commonly undiagnosed, partly because of the lack of a simple, reliable diagnostic test which can be used in clinical laboratories. The indirect immunoperoxidase technique, configured into a test kit, was provided to technicians who were trained in its use. They used the kit during a 2 year field trial in their respective clinical hospital laboratories throughout Malaysia. In an evaluation using 1,722 consecutive sera tested in those laboratories, the kit was found to have a median sensitivity for IgG detection of 0.85 (range 0.33-0.95), a median specificity of 0.94 (range 0.88-1.00), reproducibility of 0.86, and efficiency of 0.92 when compared to the reference laboratory. In a proficiency survey in which 10 laboratories received 3 coded test samples, all but 2 laboratories had results within 1 dilution of the reference laboratory in quantitating specific IgG, whereas 7 laboratories were within 1 dilution in quantitating IgM. The shelf life of the kit was at least 1 year at 4 degrees C.

Antibodies, Bacterial↗
PubMed1988

Comparative evaluation of the indirect immunoperoxidase test for the serodiagnosis of rickettsial disease.

An indirect immunoperoxidase test was compared with an indirect fluorescent antibody test and the Weil-Felix OXK test for serodiagnosis of scrub typhus by measuring the rickettsial antigen specific activity of IgG, IgM, and whole globulin. Acute and convalescent sera from 50 Rickettsia tsutsugamushi isolate-positive scrub typhus patients and from 45 febrile patients diagnosed as having diseases other than scrub typhus were tested. The receiver operating characteristic for each test showed that the indirect immunoperoxidase and indirect fluorescent antibody tests were more sensitive and specific than the Weil-Felix test using convalescent and acute as well as paired sera. The indirect immunoperoxidase test showed no cross-reactivity when R. tsutsugamushi antigen was tested against sera collected from patients living outside the scrub typhus-endemic area with diseases other than scrub typhus. The indirect immunoperoxidase and indirect fluorescent antibody tests were comparable in measured response to R. tsutsugamushi, R. typhi, and TT-118 (spotted fever group) antigen. Thus the indirect immunoperoxidase test represents a sensitive, specific, reproducible, and practical semiquantitative test for rickettsial disease diagnosis.

Agglutination Tests↗
PubMed1984

Lack of transplacental infection with scrub typhus organisms in laboratory mice.

Female mice were inoculated with either a virulent or avirulent strain of Rickettsia tsutsugamushi before (1 month and 1 week) or after (approximately 10 days) impregnation. From each group, two pregnant mothers were killed on day 20 post-impregnation, and fetuses and placentas were examined for rickettsiae. Organisms were isolated from 80% of placentas but not from the fetuses. Immediately following parturition, litters from 50% of the infected mothers were exchanged with litters from uninfected mothers. In all cases, no scrub typhus rickettsiae were found in the litters examined on days 1, 7, and 30 postpartum, and no antibody was found in sera collected 1 and 2 months postpartum.

Animals↗
PubMed1982

Serological analysis of Rickettsia tsutsugamushi isolates from North Queensland.

Fifty-two Rickettsia tsutsugamushi isolates from humans, rodents and chiggers in North Queensland were serologically characterized by the direct immunofluorescence test. A majority (71%) of the isolates was a mixture of two or more strains. The most frequently detected strains in the 52 isolates were TA716 (84%), TA763 (42%), TA686 (33%), and Karp (31%). The Gilliam strain was detected in only 4% of the isolates.

Animals↗
PubMed1982

Characterization of Rickettsia tsutsugamushi strains in two species of naturally infected, laboratory-reared chiggers.

The strains of Rickettsia tsutsugamushi found in naturally infected, laboratory-reared Leptotrombidium (Leptotrombidium) arenicola and L. (L.) fletcheri chiggers were characterized by direct immunofluorescence (FA) and by mouse and monkey virulence tests. The strains existing in the L. (L.) arenicola chiggers consisted of different combinations of TA716, TA763, TA686, Karp, and Kato. In addition to these five strains, Gilliam was found in the L. (L.) fletcheri chiggers. Results indicate that individual chiggers can be simultaneously infected with several antigenic strains of R. tsutsugamushi. Although these antigens appear to remain stable within familial lines when several generations were viewed, the antigenic patterns observed in two succeeding generations did not always correlate. This variable expression of antigens was considered to be due to a quantitative fluctuation from one generation to the next in the strains of rickettsiae combined with a lack of sensitivity of the direct FA test in detecting small numbers of antigenically different rickettsiae. Phenotypic variation was considered to be a less probable explanation. Morbidity and mortality were minimal in ICR mice fed upon by individual chiggers of either species, but infection rates were 85-99%. Tissue suspensions prepared from mice infected by L. (L.) arenicola produced higher mortality and longer duration of illness in mice than those prepared from L. (L.) fletcheri-infected mice. Silvered leaf and cynomolgus monkeys were fed upon by the two species of chiggers or inoculated with the mouse tissue suspensions. In both cases, minimal clinical responses were observed.

Animals↗
PubMed1981

Clinical and immunologic responses of silvered leaf monkeys (Presbytis cristatus) to experimental reinfection with Rickettsia tsutsugamushi.

Silvered leaf monkeys (Presbytis cristatus) that had recovered from active Rickettsia tsutsugamushi infections 14 months previously became rickettsemic when inoculated with homologous, related, or unrelated strains of R. tsutsugamushi. In contrast to the results after the initial infection that produced disease, no signs were observed after the subsequent infections. Most animals responded with detectable titers of antibody to the Karp antigen regardless of the inoculated strains. Strains recovered during rickettsemia usually had antigens related only to the challenge strains, but in three silvered leaf monkeys, antigens characteristic of both the original and the challenge strains were detected.

Animals↗
PubMed1981

Scrub Typhus antibody in cynomolgus monkeys (Macaca fascicularis) in Malaysia.

Using an indirect immunofluorescence technique, sera from 113 cynomolgus monkeys (Macaca fascicularis), trapped in Peninsular Malaysia, were screened for the presence of antibody to six prototype strains of Rickettsia tsutsugamushi combined into three polyvalent groupings: I--Karp, TA716, and TA763; II--Gilliam; and III--TA678 and TH1817. Fifteen percent (17/113) of the monkeys had antibody titers greater than or equal to 1:50 to one or more of the antigenic groups. Although a titer greater than or equal to 1:150 is generally considered indicative or prior Rickettsia tsutsugamushi infection, we selected a less than 1:25 titer as a conservative standard to insure non-infected animals. Using this criterion, 62 (55%) of the 113 monkeys were accepted for use in scrub typhus studies. The high prevalence of antibody to scrub typhus in the semi-arboreal cynomolgus monkey is in marked contrast to the low prevalence reported in the strictly arboreal silvered leaf monkeys (Presbytis cristatus). The results of this study indicate that cynomolgus monkeys should be rigorously screened for evidence of prior infection before they are included in experimental scrub typhus studies.

Animals↗