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Biomedical subjects

M K Lai

Publications and source records attributed to M K Lai.

At least 37 records · Page 2Linked to original sources
PubMed1999

Risk factors for prostate carcinoma in Taiwan: a case-control study in a Chinese population.

BACKGROUND: Although prostate carcinoma remains a rare disease among Chinese men, its incidence is on the rise. The authors conducted a hospital-based case-control study to identify risk factors for prostate carcinoma in northern Taiwan. METHODS: Patients at a selected veterans hospital or 2 military hospitals who were newly diagnosed with prostate carcinoma between August 1995 and July 1996 were included as cases (n = 90). Controls (n = 180) were comprised noncancer patients who were treated in emergency rooms and departments other than those of urology and cardiology at the same hospitals; controls were matched to cases by age (+/-5 years) and admission date (+/-4 months). Subjects were interviewed in person to elicit information regarding sociodemographic characteristics, life-style, diet, height, and weight. RESULTS: Cases and controls were similar in terms of age and the majority of sociodemographic characteristics. However, cases tended to have received more education and were less likely to have blue-collar jobs than controls. The consumption of pork was moderately higher for cases than for controls, although this difference was not statistically significant. Cases were more likely than controls to engage in exercise (odds ratio [OR] = 2.16; 95% confidence interval [CI] = 1.18-3.96) and to have a body mass index > or = 24.75 kg/m2 at ages 40-45 years (OR = 2.00; 95%CI = 1.05-3.82). In addition, cases were less likely to cook vegetables with pork lard (OR = 0.47; 95%CI = 0.24-0.91). CONCLUSIONS: The higher frequency of exercise and lower use of pork lard for cooking among cases reported in the current study suggest that cases tended to have relatively affluent life-styles compared with controls. Because less affluent families are likely to consume more vegetables than meat, these preliminary findings indicate that vegetable intake appears to have a protective effect.

Adult↗
PubMed1999

Differential expression of type 1 angiotensin II receptor mRNA and aldosterone responsiveness to angiotensin in aldosterone-producing adenoma.

Aldosterone secretion in most patients with aldosterone-producing adenomas (APAs) is typically unresponsive to angiotensin II stimulation (AII-unresponsive, AII-U). In some patients, however, plasma aldosterone increases in response to AII stimulation (AII-responsive, AII-R). This differential aldosterone responsiveness could be related to the levels of type 1 AII receptors (AT1R) in the APA. To test this hypothesis, plasma aldosterone levels in response to upright posture and/or sequential high- and low-salt diets were measured by radioimmunoassay in nine patients with APAs. AT1R mRNA levels in the adenomas were quantified by competitive reverse transcription-polymerase chain reaction and correlated to the cellular composition of the adenoma. Two patients were categorised as AII-R by an increase of plasma aldosterone greater than 50% over the baseline. The remaining seven patients who had blunted plasma aldosterone responses were classified as AII-U. Histologically, the AII-R APAs consisted predominantly of zona glomerulosa (ZG)-like cells (> 90%), while the AII-U APAs contained zona fasciculata (ZF)-like cells ranging from 28 to 72%. There was an inverse relationship between the levels of AT1R mRNA in the APA and the percentage of ZF-like cells in the adenoma (n = 9, r = 0.73, P < 0.05). In situ hybridisation findings demonstrated that AT1R mRNA was more uniform and intensive in ZG-like cells than in ZF-like cells. These results suggest that heterogenous aldosterone responsiveness to angiotensin in APAs is histologically dependent and related to the differential expression of AT1R mRNA in the adenoma.

Adenoma↗
PubMed1999

Antiandrogen hepatotoxicity in patients with chronic viral hepatitis.

OBJECTIVE: To assess whether patients with chronic viral hepatitis are at an increased risk for antiandrogen hepatotoxicity. METHODS: We retrospectively reviewed 121 prostate cancer patients who received long-term antiandrogen, either flutamide (n = 56) or cyproterone acetate (n = 65), and had normal pretreatment serum alanine aminotransferase (ALT) levels. Serological markers of hepatitis B and C viruses (HBV and HCV) were checked in 42 of the 121 patients. RESULTS: Twenty-two (18%) of the 121 patients had ALT elevations during antiandrogen therapy. Thirteen (59%) of the 22 patients were positive for either one of the two viral markers, including 7 for HBV, 4 for HCV, and 2 for both. This percentage was higher than the combined prevalence rate of positivity for HBV and/or HCV markers (<20%) in Taiwan. There was no significant differences in the percentage of positive makers among the two antiandrogen groups (p = 0.092). Although a higher incidence of hepatotoxicity was noted in the flutamide (13/56, 23%) than in the cyproterone acetate group (9/65, 14%), there were no significant differences between the two groups (p = 0.27). The time period between initiation of antiandrogen and first ALT elevation varied significantly (from 4 to 1,398 days with a median of 151 days). Half of the 14 HBV carriers and all of the 6 patients with anti-HCV developed antiandrogen hepatotoxicity. CONCLUSION: Our limited data suggested that patients with chronic viral hepatitis probably are at a higher risk of developing antiandrogen hepatotoxicity. Close monitoring of liver functions in patients with chronic viral hepatitis is advised if antiandrogen therapy is necessary. However, a large-scale study is necessary for a definitive conclusion.

Aged↗
PubMed1999

A case of extraadrenal pheochromocytoma associated with adrenal cortical nodular hyperplasia and papillary thyroid carcinoma.

A 64-year-old woman was admitted in November, 1996 for fluctuating blood pressure. There was multinodular goiter in her neck. High urine VMA and serum aldosterone were noted. Computed tomography showed an oval lesion in the left adrenal gland. Left adrenalectomy was performed and the pathology was proved to be adrenal cortical nodular hyperplasia. Fluctuating blood pressure and high urine VMA persisted after the operation. CT scan of the abdomen revealed a soft tissue mass in lower abdomen. The patient was admitted again in September, 1997. Laboratory examinations showed normal serum aldosterone, normal plasma renin activity and high urine VMA. Aspiration cytology of the thyroid gland disclosed papillary thyroid carcinoma. [131I]-metaiodobenzylguanidine image revealed a high uptake lesion in the right L-3 paravertebral area. Tumor excision and thyroidectomy were performed. The pathology was reported as extraadrenal pheochromocytoma and papillary thyroid carcinoma. Papillary thyroid carcinoma is rarely associated with pheochromocytoma. To our knowledge, this paper is the first report of a patient with extraadrenal pheochromocytoma associated with papillary thyroid carcinoma and adrenal cortical nodular hyperplasia.

Adrenal Cortex↗
PubMed1999

High-frequency oscillatory ventilation in premature infants.

BACKGROUND: Although assisted ventilation has reduced the mortality rate of premature infants, pulmonary disease is still the major cause of morbidity and mortality in very low birth weight infants. We designed this study to evaluate the efficacy and safety of high-frequency oscillatory ventilation (HFOV) in premature infants and to compare the outcome for early intervention with HFOV versus conventional ventilation (CV). METHODS: From January, 1997, to June, 1998, we analyzed premature infants with respiratory failure who required mechanical ventilation and supplemental oxygen to support adequate gas exchange in our neonatal intensive care unit. Patients were eligible if their gestational age was less than 35 weeks or their birth weight was less than 1,751 g. A total of 35 neonates were enrolled in the study. Eighteen infants were treated with HFOV, and 17 infants were treated with CV. They were treated with early intervention of HFOV or CV, within 24 hours-of-age. Patients were excluded if a lethal congenital anomaly, bacteremia, hydrops fetalis, congenital diaphragmatic hernia or intubation only for apnea were noted. Data on demographics, gas exchange and outcome parameters were collected for each patient enrolled in the study. RESULTS: No differences were noted in the demographic features between the study groups. All of the enrolled patients suffered from variable grades of respiratory distress syndrome. A significantly shorter intubation period was found in the HFOV group compared with the CV group (2.8 +/- 1.5 days vs 8.8 +/- 9.4 days; p = 0.013). CONCLUSIONS: HFOV is a safe and effective therapy for premature infants with respiratory failure due to respiratory distress syndrome.

Female↗
PubMed1999

Use of polymerase chain reaction to detect Proteus mirabilis and Ureaplasma urealyticum in urinary calculi.

In this study, we evaluated the efficacy of the polymerase chain reaction (PCR) in detecting urea-splitting microorganisms in desiccated urinary tract infection stones. Seventy-eight urinary tract stones were tested for the presence of Proteus mirabilis and Ureaplasma urealyticum by means of PCR with species-specific primers. Twenty-seven stone samples were composed of struvite and/or carbonate apatite (infection stone); 40 were calcium oxalate and/or calcium phosphate; seven were mixed, with struvite/carbonate apatite and calcium oxalate; and four were uric acid stones. PCR was performed with DNA extracted from pulverized stone pieces. Initial assays using the pulverized stone specimens spiked with microorganisms showed that PCR could not detect U. urealyticum at densities below 10(3) color changing units (CCU), or P. mirabilis at densities below 10(4) colony-forming units (CFU). PCR was negative for U. urealyticum and P. mirabilis in all metabolic stones from patients. P. mirabilis was detected by PCR in 10 of 34 patients with infection stones. Preoperative urine cultures grew P. mirabilis in three of these 10 patients, and were negative for P. mirabilis in the other seven. U. urealyticum was detected by PCR in stone samples from four patients, two of which were also PCR-positive for P. mirabilis. All four of these patients had infection stones: two had residual stones, and the other two had recurrence of urinary stones after their operations. These results demonstrate that microorganisms in urinary stones can be detected by PCR even when the voided urine culture is negative. Investigations into the role of bacterial infection in stone formation will require further improvements in the sensitivity of PCR assays for pathogen detection.

Adult↗
PubMed1998

An ex vivo evaluation of regulatory role of biogenic amines in rat seminal vesicle after pharmacological manipulation.

We studied the neural regulation of seminal vesicles (SV) by determining the changes of intraluminal pressure of rat SV in response to an electric stimulation of the lesser splanchnic nerve (LSN). After pharmacological manipulation with neurotoxin, the contents of monoamines and their metabolites in SV were estimated. In rats receiving electric stimulation of the LSN, an increase of intraluminal pressure was obtained with a reduction of the serotonergic turnover rate in SV. An intraperitoneal injection of DSP-4 (100 mg/kg), the noradrenergic neurotoxin, into rats decreased the level of norepinephrine (NE) in SV significantly but did not influence this functional response. Also, the intraluminal pressure was lowered by an intrathecal injection of 6-OHDA (20 microg/rat) to denervate spinal monoaminergic nerves in rats although the contents of monoamines in SV were not changed. This indicates that noradrenergic neurotransmission appears unimportant in this regulation. The lowering of intraluminal pressure in rats by 6-OHDA is mainly related to an attenuation of dopaminergic neuroregulation from the decrease of turnover rate of DA. Otherwise, an intrathecal injection of 5,7-DHT (60 microg/rat) to abolish spinal serotonergic nerves did not influence the level of monoamines in SV but increased the intraluminal pressure indicating an involvement of inhibitory regulation from spinal serotonergic pathway. These results suggest that contraction by electric stimulation of the LSN in Wistar rat SV is mainly regulated by the dopaminergic nervous pathway and an inhibitory regulation of the serotonergic nervous pathway from spinal cord while the noradrenergic nervous system seems unimportant for this regulation.

5,7-Dihydroxytryptamine↗
PubMed1998

The usefulness of prostate-specific antigen (PSA) density in patients with intermediate serum PSA level in a country with low incidence of prostate cancer.

OBJECTIVES: To evaluate if a calculated PSA density (PSAD) prior to biopsy could be useful to determine the need for prostate biopsies in patients with serum PSA levels of 4.1-20.0 ng/mL in a country with low incidence of prostate cancer (PCa). METHODS: A total of 185 consecutive patients aged 50-79 years who underwent prostate biopsies were evaluated by correlating the biopsy results with the results of digital rectal examination (DRE), transrectal ultrasonography (TRUS), serum PSA levels, and PSAD. Prostate volume was calculated from TRUS using prolate ellipse formula and PSAD was obtained by dividing serum PSA level by prostate volume. RESULTS: In this study population, 27 cases (14.6%) had positive biopsies. Of 158 cases with negative biopsies, 43 (23.2%) had histologically verified prostatic inflammation. The diagnostic value of DRE and TRUS was hampered by unsatisfactory sensitivity and specificity in differentiating patients with positive biopsies from those with negative biopsies. The use of PSAD alone as an indicator for biopsy was also limited by its low specificity. A PSAD cutoff value of 0.15 resulted in a sensitivity of 100% and a specificity of only 12%. Prostatic inflammation was a confounding factor for the inadequate specificity of DRE, TRUS and PSAD. Combined use of DRE and PSAD provided the best information regarding the need for biopsies. Accordingly, if the 47 patients (25.4%) who presented with both a negative DRE and a PSAD < or = 0.20 were not biopsied, the rate of positive biopsy could have increased to 19.6% (27 of 138) without missing any cancer detection. CONCLUSIONS: It is concluded from this study that for patients with serum PSA levels of 4.1-20.0 ng/mL, biopsies should only be recommended for those with abnormal DRE and/or PSAD >0.20.

Aged↗
PubMed1998

The effect of biological dyes and contrast media on the vas deferens in Long Evans rats.

The conventional diagnostic procedure of vasography utilizes a contrast medium to evaluate the patency of the vas deferens. With the development of microsurgical reconstruction for obstructive azoospermia in the past two decades, intraoperative vasography with saline or biological dye injection has replaced the use of radiographic contrast media. However, there are few reports on the effect of biological dyes on the healthy vas deferens. Therefore, we used experimental vasography to evaluate histological changes and functional patency of the vas deferens after infusion with a contrast medium and biological dye. Four groups of 10 Long Evans male rats were injected by vasopuncture with 1% methylene blue, 1% gentian violet and 38% Urografin or saline into the vas deferens. The animals were killed 30 days later, and the vasa deferentia were excised and examined for histological changes and for functional patency. Vasopuncture with saline injection induced minimal change both at the puncture site and in the distal vas deferens. In both the Urografin- and methylene blue-injected groups, inflammation at the puncture site was found in 20-22% of cases, and 10-11% of cases revealed functional obstruction of the vasal lumen. In the gentian violet-injected group, severe histological and obliterated changes were found in all cases. Leakage of the dye and contrast medium or the sperm reaction may be responsible for the inflammation; otherwise, methylene blue and urografin did not seem to be harmful to the vas deferens. Although gentian violet is a blue dye, as is methylene blue, it has marked destructive effects on the vas deferens. It is concluded that some biological dyes used for vasal injection can cause occlusion of the vasal lumen, while inflammatory responses can occur from placing a needle transmurally.

Animals↗