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Biomedical subjects

P Lui

Publications and source records attributed to P Lui.

At least 19 recordsLinked to original sources
PubMed2001

Telomerase activity in prostate sextant needle cores from radical prostatectomy specimens.

Human telomerase acts to maintain functioning telomeres, which are required for cellular immortality and very likely for cancer progression. Telomerase activity is present in about 85% of human cancers tested, but it has not been found in most human somatic cells and tissues. We used the Telomeric Repeat Amplification Protocol to perform telomerase activity assays on sextant needle core samples obtained from 35 freshly excised radical retropubic prostatectomy specimens. Similar assays were done on prostatic tissues obtained by means of other urologic procedures from 8 patients without prostate cancer. Telomerase activity was found in one or more specimens from 32 of 35 prostate cancer patients (91%), but was not detectable in all biopsy specimens from 7 of 8 cancer-free patients (88%). Further analysis showed that cancers more poorly differentiated, with higher Gleason scores, were always associated with a higher rate of telomerase detection and stronger telomerase activity. Moreover, comparison of telomerase activity in needle core samples with the volume of cancer in surrounding tissue as observed on corresponding histologic slides showed that stronger activity was positively correlated with a higher cancer volume. Prognostic indicators of prostate cancer and the expression of telomerase appear to be linked. The presence of telomerase activity in prostate tissue may aid in the detection of prostate cancer and produce additional prognostic information.

Journal Article↗
PubMed2000

Detection of telomerase activity in prostatic fluid specimens.

We report here the extended use of the telomeric repeat amplification protocol (TRAP) assay for the detection of telomerase activity in fresh prostatic fluid obtained from anesthetized patients. Telomerase activity was detected in pellet extract and/or supernatant fluid of specimens obtained from 25 of 30 prostate cancer (PCa) patients (83%), whereas no activity was similarly detectable in specimens taken from 8 of 9 patients (89%) without clinical evidence of PCa. The positive predictive value (PPV) of the TRAP assay for PCa in this pilot study was 96%. We found a strong correlation between telomerase activity in prostatic fluid specimens and serum prostate specific antigen (PSA) values. Telomerase activity was found in 84% of specimens from patients with PSA values >4 ng/ml, whereas in specimens from patients with PSA values </=4 ng/ml, only 29% tested positive for telomerase activity. In patients with PSA values above the standard 0 to 4 ng/ml reference range, the PPV of the TRAP assay was 84%. Furthermore, telomerase activity could be detected in 85% of the specimens from PCa patients with Gleason scores >4. In prostatic fluid from PCa patients with Gleason scores of </=4, telomerase activity was detected 50% of the time. The PPV was 92% when a Gleason score of 4 was used as the lower limit. This pilot study raises the possibility of utilizing telomerase activity as an aid in PCa detection.

Journal Article↗
PubMed2000

Inhibition by neuropeptide Y of fentanyl-induced muscular rigidity at the locus coeruleus in rats.

The aim of this study was to evaluate the effects of centrally administered neuropeptide Y (NPY) on muscular rigidity induced by fentanyl in Sprague-Dawley rats. They were anesthetized with ketamine (120 mg/kg, i.p.) and their lungs were mechanically ventilated. Intravenous administration of fentanyl (100 microg/kg) consistently evoked a significant increase in the electromyographic activity (EMG) recorded from the sacrococcygeus dorsalis lateralis muscle. This implied muscular rigidity was appreciably attenuated by intracerebroventricular administration of NPY (4 nmol/2.5 microl). Microinjection of NPY (40 or 160 pmol/50 nl) into the bilateral locus coeruleus (LC) elicited an inhibition of the EMG activation induced by fentanyl in a dose-dependent manner. Microinjection of 160 pmol NPY plus antiserum against NPY (NPY(Ab), 1:20) into the LC failed to suppress fentanyl-induced muscular rigidity. However, this implied muscular rigidity was not affected by NPY plus normal rabbit serum (NRS, 1:20). In addition, NPY(Ab) or NRS per se had no substantial effect on the rigidity. Microinjection of NPY (160 pmol) into the areas adjacent to the LC did not attenuate the rigidity. Our results suggest that the centrally administered NPY attenuated fentanyl-induced muscular rigidity by acting at the LC, but endogenous NPY may not be involved in this process.

Animals↗
PubMed2000

Radical retropubic prostatectomy: bladder neck preservation versus reconstruction.

PURPOSE: We compare bladder neck contracture, urinary continence and positive surgical margin rates after bladder neck preservation and excision with radical retropubic prostatectomy. MATERIALS AND METHODS: A retrospective analysis of clinical and pathological findings, and followup of 220 patients who underwent radical retropubic prostatectomy was performed. Patients were divided into 3 groups of bladder neck preservation (101), "tennis racket" reconstruction (63) and anterior bladder tube reconstruction (56). RESULTS: Mean followup was 19.7, 36.7 and 16.2 months, respectively, for bladder neck preservation, tennis racket reconstruction and anterior bladder tube reconstruction. Overall, bladder neck contracture occurred in 22 of 220 cases (10%), including 5 of 101 (5%) with bladder neck preservation, 7 of 63 (11%) with tennis racket reconstruction and 10 of 56 (18%) with anterior bladder tube reconstruction, which approached statistical significance (p = 0.061). Urinary continence was assessed by a third party telephone interview of 165 patients. Continence rates at 1 year were 93% for bladder neck preservation, 96% for tennis racket reconstruction and 97% for anterior bladder tube reconstruction, which was not statistically significant (p = 0.68). Positive margin rates were 27.4% with bladder neck preservation versus 30.5% with excision, which was not significantly different. CONCLUSIONS: There are no statistically significant differences in return of urinary continence, bladder neck contracture rates or positive margins between bladder neck preservation and excision.

Adult↗
PubMed1997

Topically applied aspirin rapidly decreases histamine-induced itch.

The effect of topical aspirin and its model vehicle dichloromethane on itch experimentally induced with histamine was studied in 16 subjects, using a visual analogue scale and computerized aspirin, but not its vehicle, significantly reduced itch duration (p = 0.001) and decreased itch magnitude as measured with a visual analogue scale (p < 0.04). Histamine injection caused elevation of warmth sensation threshold (p = 10(-8)) but did not affect cold and heat pain thresholds. Aspirin and vehicle application did not affect thermal and pain thresholds during histamine-induced itch. The current data suggest that topical application of aspirin may be beneficial for the treatment of histamine-mediated itch. Its therapeutic role in the management of clinical itch remains to be determined.

Administration, Topical↗
PubMed1995

Laparoscopic cutaneous ureterostomy: technique for palliative upper urinary tract drainage.

Extensive pelvic carcinomatosis often results in bilateral ureteral obstruction and renal parenchymal loss. Percutaneous nephrostomies can be used for palliative means but may be poorly tolerated. Laparoscopic techniques can be applied to obtain a more permanent urinary diversion. An elderly gentleman with extensive pelvic transitional cell carcinoma of the bladder and only one functioning renal unit underwent percutaneous nephrostomy tube placement in combination with palliative cytoreductive radiation therapy. Poor patient tolerance led to repetitive nephrostomy tube replacement. A cutaneous ureterostomy was chosen as a more permanent urinary diversion, and laparoscopic techniques allowed this to be accomplished expeditiously. At 18 months postoperatively, the patient's unstented cutaneous ureterostomy is functioning well, and the serum creatinine concentration remains normal.

Carcinoma, Transitional Cell↗
PubMed1995

Electrovaporization of the prostate: new technique for treatment of symptomatic benign hyperplasia.

This pilot study evaluated the efficacy of a newly configured roller electrode (Circon/ACMI Vaportrode) in the treatment of symptomatic benign prostatic hyperplasia. The electrode is used with a cutting current and an otherwise-standard (ACMI) resectoscope. Thirty-four patients with significant symptoms of bladder outlet obstruction were treated and evaluated. Among them, 20 were in urinary retention, and 14 had moderate to severely symptomatic bladder outlet obstruction. Thirty-three patients are voiding and available for follow-up. The other patient has not returned. All available patients have shown both subjective and objective voiding improvement. In the evaluable patients, the AUA Symptom Index decreased from a mean of 26 to 12. The mean postoperative peak urinary flow rate was 13 mL/sec. Complications occurred in three patients (post-operative bleeding in one, urinary retention in two). Electrovaporization allowed definitive treatment of bladder outlet obstruction with subjectively better visibility than transurethral resection (TURP). The potential for fluid and electrolyte shifts and resulting complications appears to be less than with TURP. Further study of this technique appears warranted.

Aged↗
PubMed1994

Pregnancy after unilateral oophorectomy in a woman with hyperthecosis ovarii. A case report.

Ovarian hyperthecosis has been described exclusively as bilateral. It occurs predominantly in perimenopausal women but may be seen at any age after puberty. In a young woman, stromal hyperthecosis is characterized by virilism, menstrual disorders and infertility. Ovarian suppression therapy, induction of ovulation and wedge resection of the ovaries have been ineffective, and only bilateral oophorectomy has caused regression of virilism in these patients. Conservative surgery in appropriate cases may save many young women desiring pregnancy from having bilateral oophorectomy. This case report describes a unique situation in which a young woman with ovarian hyperthecosis achieved three pregnancies after unilateral oophorectomy, indicating the possibility of unilateral ovarian hyperthecosis in our patient.

Adult↗
PubMed1989

Chemiluminescence in a macrophage cell line modulated by biological response modifiers.

We have studied a murine macrophage cell line, J774, and found these cells capable of a zymosan-triggered chemiluminescent oxidative burst. Such activity was enhanced by preincubation with Corynebacterium parvum (CP), bacillus Calmette-Guerin, and lipopolysaccharide (LPS). Under similar conditions, CP and LPS were shown to enhance J774-mediated tumor cell lysis. We have also demonstrated that murine interferon alpha + beta rendered J774 cells more sensitive to the actions of CP and LPS. These results indicate that J774 cells may be useful for the in vitro evaluation of biological response modifiers as well as the study of oxygen radical production by macrophages.

Adjuvants, Immunologic↗
PubMed1987

Rapid purification of phospholamban by monoclonal antibody immunoaffinity chromatography.

Monoclonal antibodies have been raised against canine phospholamban purified by sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE). Four of twenty-four antibodies were purified to close to homogeneity from mouse ascites. All four antibodies could react with isolated bovine cardiac sarcoplasmic reticulum (SR) to result in the stimulation of ATP-dependent Ca2+ pump activity and blocking of phospholamban phosphorylation by cAMP-dependent protein kinase. Relative efficiencies of antibodies in Ca2+ pump stimulation and on phospholamban phosphorylation were not correlated. An immunoabsorbent prepared by conjugating antibody Al to Affi-Gel 10 was used for the purification of phospholamban. Isolated bovine cardiac SR was solubilized in a buffer containing deoxycholate and the soluble fraction was applied to the immunoaffinity column. After washing the column with a series of detergent-containing buffer solutions, the column-bound protein which contained essentially pure phospholamban was eluted by a buffer containing 2.8 M MgCl2. The phospholamban recovery from the immunoaffinity column was close to 100%; the overall yield of purification from SR vesicles was about 70%. SDS-PAGE analysis showed that purified phospholamban consisted of a 25 and 5 kilodalton (kDa) protein species. Upon brief boiling (20 s) of the sample in SDS-PAGE sample buffer, five molecular species ranging from 5 to 25 kDa could be detected by immunotransblotting following SDS-PAGE. This observation supports the notion that phospholamban is composed of five 5-kDa polypeptides. The pure phospholamban could be phosphorylated maximally by cAMP-dependent protein kinase to 1-1.5 mol phosphate/mol phospholamban (25,000 g). This stoichiometry of phosphorylation could be increased to about 5 upon addition of the immunoaffinity column flow through fraction.

Adenosine Triphosphatases↗
PubMed1986

The use of monoclonal antibodies for the species and tissues distribution of phospholamban.

Monoclonal antibodies have been raised against canine phospholamban. Two antibodies have been used in the study of phospholamban distribution in tissues, and in different animal species. The antibodies recognized the three different forms of phospholamban: non-phosphorylated, phosphorylated, and dissociated forms. A survey of nine rabbit tissues revealed that phospholamban is a cardiac muscle specific protein. Phospholamban from different mammalian hearts were found to be identical with respect to molecular weight and antigenicity.

Animals↗
PubMed1986

Ultrasonography in the diagnosis of cholestatic jaundice.

Fifty consecutive patients (32 males and 18 females) with cholestatic jaundice were examined by grey-scale ultrasound from June 1981 to June 1983. All patients were studied without access to case notes. All patients had a diagnosis established by subsequent liver biopsy, clinical course, surgery or autopsy. Using the presence or absence of a dilated biliary system as the criterion, intrahepatic or extrahepatic cholestasis was correctly differentiated in 48 of the 50 patients, giving an overall accuracy of 96%. All 16 patients with intrahepatic cholestasis were correctly identified. Two of the 34 patients with extrahepatic cholestasis, each of whom had biliary stones, were misdiagnosed as intrahepatic cholestasis. In the 34 patients with extra-hepatic cholestasis, site of obstruction was defined in 55.9%, and specific aetiology diagnosed in 44.1%. Ultrasound proves to be an accurate method for the evaluation of cholestatic jaundice, and would have a definite value as a screening test before proceeding to invasive studies.

Cholestasis, Extrahepatic↗
PubMed1986

Liver abscess--a clinical study.

Forty consecutive cases of liver abscess from the Department of Medicine III, Singapore General Hospital, from 1978 to July 1983 were reviewed. Nineteen (47.5%) were amoebic, 15 (37.5%) pyogenic and 6 (15%) of unknown aetiology. Of the first 20 cases from 1978 to 1980, amoebic abscesses (60%) predominated. An increased incidence of pyogenic abscess constituting 50% was seen in the next 20 cases. Though all racial groups were affected, a predilection among Indians was seen. Males outnumbered females (4:1), and peak incidence occurred in the 40 to 70 age group (62.5%). Fifty percent presented early (less than one week of symptoms) to hospital. Common physical signs were fever (97.5%) and hepatomegaly (92.5%). Investigations showed leucocytosis in excess of 10,000 WBCs/cmm (87.5%), an ESR of 80 mm/hr (80%) and an elevated alkaline phosphatase of at least twice normal (73.6%). Single abscesses (72.5%) located in the right lobe were more likely to be amoebic. Where abscesses were multiple, they were more likely to be pyogenic (63.6%). Two-thirds of the pyogenic abscesses were due to either Klebsiella species or E. coli. Medical treatment consisted of broad spectrum antibiotics, usually in combination with metronidazole. Aspiration or drainage (open or closed) was employed when indicated. These were carried out more often for pyogenic than amoebic abscesses. Amoebic abscesses responded faster to treatment compared to pyogenic abscesses. Mortality in the first 20 cases prior to 1981 was 30%, being mainly confined to pyogenic abscesses. However, after 1981, there has been no mortality in the ensuing 20 cases.

Adolescent↗
PubMed1985

Renal preservation following severe ischemia and prophylactic calcium channel blockade.

The ability of the calcium channel blocker verapamil to prevent renal ischemic damage was assessed in a randomized double blind study of 41 rats. Study animals received either intravenous verapamil or placebo prior to renal pedicle occlusion and contralateral nephrectomy. Rats receiving verapamil pretreatment demonstrated significantly greater functional preservation 48 hours after ischemia (p less than 0.005) and exhibited better overall survival rates. In this study verapamil provided protection against renal damage following ischemia.

Animals↗
PubMed1982

Premalignant changes in normal appearing epithelium in patients with squamous cell carcinoma of the upper aerodigestive tract.

Biopsy specimens of "normal" mucous membrane of patients susceptible to the effects of the carcinogens of tobacco revealed morphologic abnormalities on electron microscopic examination that were consistent with the concept that carcinogenesis is a multistep process of sequential neoplastic development extending over a long period of time. Such changes in the upper aerodigestive tract are probably tobacco induced and may be reversible if tobacco exposure is eliminated. Use of the electron microscope can provide the clinician with an accurate assay of the severity of mucosal alterations induced by tobacco. The ability to detect such morphologic abnormalities should provide another deterrant to smoking and a useful tool in the further study of these phenomena.

Adult↗