Prevalence and epidemiologic characteristics of urolithiasis in Seoul, Korea

OBJECTIVES

To study the epidemiologic details of urolithiasis in Seoul, Korea. The prevalence of urolithiasis varies by different regions in the world and has been reported to be 4% to 15%.

METHODS

A total of 2643 persons 40 to 79 years old living in Seoul were selected by stepwise random sampling. Questionnaires were used and completed by trained interviewers concerning whether the subjects had experienced urinary stone disease at any time in their life.

RESULTS

Of 2643 persons interviewed, 65 experienced 78 episodes of urinary stone formation in their lifetime. Calibrated after the Seoul population census, the overall standardized lifetime prevalence rate was estimated to be 3.5%, 6.0% in men and 1.8% in women. The point prevalence rate was estimated to be 0.9%, 1.9% in men and 0.3% in women. Most of the urinary stone diseases were diagnosed at the fifth decade. Kidney stones in family members were present in 8.1% of patients with stones and 4.1% of stone-free control individuals. Twenty percent of the patients with stones experienced recurrences.

CONCLUSIONS

In this first systematically assessed epidemiologic survey about the rate of urolithiasis in Korea, 6.0% of Korean men and 1.8% of women are expected to experience urinary stone disease during their lifetime.

Thrombospondin-1, vascular endothelial growth factor expression and their relationship with p53 status in prostate cancer and benign prostatic hyperplasia

OBJECTIVE

To evaluate the expression of thrombospondin-1 (TSP-1, a potent inhibitor of angiogenesis) and vascular endothelial growth factor (VEGF, an important angiogenic factor in solid tumours) in prostate cancer, and their relationship with p53 status.

PATIENTS AND METHODS

Using immunohistochemistry, the expression of VEGF, TSP-1 and p53 was assessed in 82 archival tissue specimens from 23 patients with benign prostatic hyperplasia (BPH), 22 with localized prostate cancer and 37 with metastatic prostate cancer. Seven of the last group had received androgen deprivation therapy. The relationship between the expression of VEGF, TSP-1 and p53 status was also evaluated with tumour grade and stage in patients with prostate cancer.

RESULTS

The seven patients receiving hormonal treatment were excluded from the analysis because androgen deprivation significantly increased TSP-1 and decreased VEGF expression (both P < 0.01). Immunohistochemical analysis showed significantly higher VEGF and significantly lower TSP-1 expression (both P < 0.01) in prostate cancer than in BPH tissues. There was also significantly higher VEGF and significantly lower TSP-1 expression (both P < 0.05) in tissues from metastatic than localized prostate cancer. There was no significant correlation between VEGF or TSP-1 expression and Gleason score, but a significant inverse correlation between TSP-1 and VEGF expression. There was a significant association between VEGF expression and p53 status (P < 0.05), but TSP-1 expression was not associated with p53 status.

CONCLUSIONS

Angiogenic factors, including VEGF and TSP-1, might be important in the development and progression of prostate cancer. These changes seem to be influenced by p53 status. Identifying the angiogenic factors involved in prostate cancer might lead to the development of diagnostic or therapeutic strategies based on anti-angiogenesis.

Daytime sleepiness and other sleep disorders in Parkinson's disease

BACKGROUND

PD is associated with a variety of sleep problems. The dopamine agonists (DA) pramipexole and ropinirole were recently implicated in causing "sleep attacks" and motor vehicle accidents.

METHODS

In order to determine the overall rate of subjective sleep problems in PD and to determine if any factors, including specific medications, correlate with sleep pathology, the authors surveyed consecutive patients with PD seen over a 3-month period in a Movement Disorders Clinic. The authors collected demographic and medication data, and the patients completed the Epworth Sleepiness Scale (ESS), questions assessing the presence of restless legs syndrome (RLS), a modified National Sleep Foundation sleep survey, and specific questions regarding falling asleep while driving.

RESULTS

A total of 320 patients completed the questionnaire. The authors eliminated 17, six for incomplete data and 11 for having a primary diagnosis other than PD. The mean age of the remaining 303 patients was 67.1 +/- 10.7 years, and the mean duration of PD was 9.1 +/- 5.7 years. The ESS scores averaged 11.1 +/- 5.9, and in 50.2% of patients the score was abnormally high (>10). Stepwise regression analysis found that sleepiness correlated with longer duration of PD (p < 0.001), more advanced PD (p < 0.004), male sex (p < 0.001), and the use of any DA (p < 0.003). The soporific effects of the three most common DA (pramipexole, ropinirole, and pergolide) were similar. Falling asleep while driving was reported by 63/279 (22.6%) of current drivers and correlated with higher ESS scores (p < 0.05). Other sleep disorders, including RLS, were also frequently reported.

CONCLUSION

Daytime sleepiness is common in PD and correlates with more advanced and longer duration of PD, and male sex. The DA were also independently associated with daytime sleepiness, but in this group, no single DA was more culpable than the others.

Molecular identification of Oxalobacter formigenes with the polymerase chain reaction in fresh or frozen fecal samples

OBJECTIVE

To develop a simple and rapid polymerase chain reaction (PCR) method for detecting Oxalobacter formigenes (which degrades oxalate in the gut) in fecal specimens from healthy volunteers and patients with urolithiasis, and to determine whether O. formigenes can be detected in frozen or fresh fecal samples.

MATERIALS AND METHODS

Whole bacterial DNA was isolated directly from fresh and frozen fecal samples obtained from 30 healthy volunteers free from urolithiasis and from fresh fecal samples obtained from 38 patients with urolithiasis. Genus-specific oligonucleotide sequences were designed, corresponding to homologous regions residing in the oxc gene that encodes for oxalyl-coenzyme A decarboxylase. A PCR-based assay was used on both fresh and frozen fecal samples, and the nucleotide sequences analysed to confirm oxc.

RESULTS

A PCR product of 416 bp encoding the oxc gene was detected in 23 (77%) of 30 healthy volunteers free from urolithiasis and in 14 (37%) of 38 patients with urolithiasis. In healthy volunteers, the results of PCR for the fresh and the frozen samples were identical in each subject. The nucleotide sequence analysis showed that the sequence of the amplified product was compatible with that of oxc.

CONCLUSION

O. formigenes can be identified easily and efficiently using this PCR-based detection system. The colonization rate of O. formigenes in patients with urolithiasis was significantly lower than that in healthy volunteers known to be free from urolithiasis. Furthermore, as the PCR-based assay results in the frozen fecal samples were identical to those from fresh samples in each subject, immediate processing of fecal samples may not be necessary to detect O. formigenes in the clinical setting.

Ethnic differences in the age-related distribution of serum prostate-specific antigen values: a study in a healthy Korean male population

OBJECTIVES

To further improve the use of prostate-specific antigen (PSA) as a screening test for prostate cancer in Asian countries, we sought to establish the normal distribution of serum PSA values in Korean men, because, until recently, studies conducted to establish normal serum PSA values have involved few Asian populations.

METHODS

Between May 1995 and June 1997, 5805 healthy Korean men 30 to 79 years old who visited our hospital for a routine health checkup were entered into a prospective study of early screening for prostate cancer. All men underwent detailed clinical examinations, including a digital rectal examination and serum PSA determination. All men who were more than 50 years old with abnormal digital rectal examination findings and/or an elevated serum PSA level (greater than 4.0 ng/mL) also underwent transrectal ultrasound-guided sextant biopsy. Four were found to have cancer and were excluded from the analysis.

RESULTS

The median serum PSA concentration (5th to 95th percentile range) was 0.8 ng/mL (0.2 to 1.8) for patients 30 to 39 years old (n = 1382); 0.8 ng/mL (0.2 to 2.0) for patients 40 to 49 years old (n = 1776); 0.9 ng/mL (0.2 to 2.4) for those 50 to 59 years old (n = 1775); 1.0 ng/mL (0.2 to 3.9) for men 60 to 69 years old (n = 746); and 1.3 ng/mL (0.5 to 6.3) for patients 70 to 79 years old (n = 122). The serum PSA concentration correlated with age (P <0.001), with an increase by approximately 1.2% annually, although the statistical correlation was weak (r = 0.16). Almost no change occurred in the median serum PSA value in patients 50 years old or younger; a gradual increase was observed in patients older than 50. In those 50 years old or older, the median and 95th percentile serum PSA values for Korean men were lower than those for white men.

CONCLUSIONS

Contrary to earlier observations that the serum PSA level strongly correlates with age, the influence of age on serum PSA was found to be weaker in this study. Moreover, the results also demonstrated that the distribution of the serum PSA level differs along ethnic lines. The cutoff value for serum PSA in mass screening for prostate cancer should be adjusted in nonwhite races.

The application of an anti-angiogenic gene (thrombospondin-1) in the treatment of human prostate cancer xenografts

Angiogenesis is a critical event for solid tumor growth and metastasis. Within a given microenvironment, the angiogenic response is determined in part by the balance between angiogenesis inducers and inhibitors. The aim of this study was to establish a thrombospondin-1 (TSP-1) ( an antiangiogenic gene) expression vector, and to determine the feasibility for use of TSP-1 in prostate cancer gene therapy. The results of this study showed that pCR-TSP-1, the cloned TSP-1 expression plasmid vector, expressed the TSP-1 gene efficiently in DU145, a human prostate cancer cell line. pCR -TSP-1 did not exert any significant growth inhibitory activity on the tested cell line in vitro. However, TSP-1 overexpression inhibited the growth of DU-145 xenografts in Balb/c nude mice when directly transfected with pCR-TSP-1 in combination with a liposomal agent (DOSPER). Histological analysis showed that there were extensive areas of necrosis in the TSP-1 overexpressing tumors, whereas no necrotic foci were observed in the control tumors. Furthermore, the microvessel density was lower in the TSP-1 overexpressing tumors compared to the control tumors. These results suggest that TSP-1 may be a potentially useful gene for prostate cancer gene therapy.