Altered Expression of Peritoneal Aquaporin-1 and Water Transport during Long-term Peritoneal Dialysis in Rats / 대한신장학회잡지

BACKGROUND: The present work was designed to examine the altered expression of peritoneal AQP-1 and water transport of peritoneal membrane during the long-term peritoneal dialysis with hypertonic glucose solution in rats. METHODS: Eighteen Sprague-Dawley male rats were randomly divided into 2 groups: control rats (n=6) with peritoneal catheter but not dialyzed; rats with peritoneal dialysis (PD) (n=12) were dialyzed with 4.25% glucose dialysate for all exchanges. Before completion of the study, 4 animals in PD group were euthanized owing to nonfunctional catheters or peritonitis, leaving 14 animals for the analysis. Dialysis exchanges were performed 3 times a day with 25 mL/each exchange for 12 weeks. Immunoperoxidase staining was performed using monoclonal anti-AGE antibody and polyclonal anti-AQP-1 antibody. The slides were read by 5 different examiners in a blind fashion. The staining intensity was graded semiquantitively from 0 to 3. The peritoneal membrane function was assessed by performing one-hour peritoneal equilibration tests every 6 week for comparing transport characteristics. Peritoneal membrane transport rate was assessed by D/P of urea nitrogen and D/Do of glucose. Water transport of peritoneal membrane was assessed by D/P of sodium at 12 week. RESULTS: The expression of peritoneal AQP-1 was increased in rats with PD, compared to control rats. Consistent with this, D/P of sodium in rats with PD was significantly decreased compared to control rats (0.58+/-0.04 vs 0.86+/-0.07, p<0.05), indicating high peritoneal water permeability in response to long-term peritoneal dialysis. Moreover, rats with PD were associated with significantly lower D/Do of glucose and higher D/P of urea nitrogen, suggesting high peritoneal membrane transport. CONCLUSION: High expression of peritoneal AQP-1 was associated with an increased peritoneal water permeability in response to long-term peritoneal dialysis with 4.25% glucose for 12 weeks. The underlying mechanisms for the increased AQP-1 expression need to be examined whether it is due to the continuous exposure to the dialysis solution containing high glucose concentration itself or compensatory effects of slowly developed concomitant ultrafiltration failure in chronic peritoneal dialysis.

Experimental Urinary Stone Formation by Sex Hormones in Rats and Analysis of Composition of the Stones / 대한비뇨기과학회지

PURPOSE: The incidence of renal stones is three times higher in men than women due to sex hormones, and most are calcium oxalate stones. Therefore, the effects of testosterone and estrogen in the formation of urinary stones were investigated. MATERIALS AND METHODS: One hundred female Sprague-Dawley rats were divided into seven groups. The first was the control group; the second was injected with testosterone cypionate into the muscle, every week; the third was fed tamoxifen only, everyday; the fourth was oophorectomized; the fifth was fed tamoxifen after an oophorectomy; the sixth was treated with testosterone after an oophorectomy; and the seventh was injected with testosterone, weekly, and fed tamoxifen everyday after an oophorectomy. The bladder stone formation and degree of renal crystal deposition of the control group was compared with those of the other groups. The composition of the bladder stones was analyzed by SEM (scanning electron microscopy)-EDX (energy dispersive X-ray microanalysis). RESULTS: Bladder stones were found in 9 rats from group 6 only, which also showed the most predominant renal crystal deposition rate (65.5%). There was a statistical significance in the renal crystal deposition rate only between groups 6 and 1. According to SEM-EDX analysis of the bladder stones, they were composed of struvite and apatite. CONCLUSIONS: It is suggested that testosterone and estrogen influenced the formation of struvite and apatite stones.

Glial Choristoma in the Middle Ear and Mastoid Bone: A Case Report

Heterotopic brain tissue usually involves extracranial midline structures of the head and neck such as nose, nasopharynx, and oral cavity. Its occurrence in the non-midline structures, including middle ear, is rare. We described a 50-yr-old-man with heterotopic glial tissue in the middle ear and mastoid bone. The patient presented with progressive hearing loss for 8 yr. There was no history of congenital anomalies, trauma, or ear surgery. Computed tomography revealed a mass-like lesion with soft tissue density occupying the middle ear cavity and mastoid antrum. At the operation, a graywhite fibrotic mass was detected in the epitympanic area. Mesotympanum and ossicles were intact. The patient underwent left simple mastoidectomy with type I tympanoplasty. During operation, definite cranial bone defect or cerebrospinal fluid leakage was not found. Histologically, the lesion was composed of exclusively mature, disorganized glial tissue with fibrovascular elements in a rather loose fibrillary background. Glial tissue showed diffuse positive reaction for glial fibrillar acidic protein and S100 protein on immunohistochemical study.

Induction of Apoptosis by alpha1-Adrenoceptor Antagonists in Benign Prostatic Hyperplasia / 대한비뇨기과학회지

PURPOSE: Recent evidence has indicated that alpha1-adrenoceptor antagonists induce prostate apoptosis in patients with benign prostatic hyperplasia (BPH). In this study, the effects of different alpha1-adrenoceptor antagonists, on the apoptosis and cell proliferation in the prostatic glandular epithelium and stroma of patients with benign prostatic hyperplasia, were evaluated. MATERIALS AND METHODS: A retrospective analysis was performed on BPH patients for the relief of lower urinary tract symptoms; an untreated (control) group (n=28), and patients treated with terazosin (n=26), doxazosin (n=27) and tamsulosin (n=15) were included. Archival prostate specimens were selected on the basis of availability of previous TURP (transurethral resection of the prostate) specimens. Terazosin, doxazosin and tamsulosin (2-8mg/day) treatment periods ranged from 1 week to 6 years. Ki-67 immunostaining and the TUNEL assay were used to evaluate the proliferative and apoptotic indices for both the epithelial and stromal components of prostate specimens. RESULTS: A significant induction of apoptosis was observed in patients treated with the alpha1-adrenoceptor antagonists, terazosin and doxazosin, compared with the untreated control group (p0.05). CONCLUSIONS: Our findings demonstrated that alpha1-adrenoreceptor antagonists may regulate the prostate growth, by inducing apoptosis in both the epithelial and stromal cells, with little effect on the cell proliferation. Apoptosis-mediated prostate stromal regression appears as an additional molecular mechanism underlying the therapeutic response to alpha1-adrenoceptor antagonists in the treatment of BPH.

Altered Expression of Renal AQP1, AQP2 and NHE3 in Puromycin Aminonucleoside Induced Nephrotic Syndrome: Intervention by Alpha-MSH Treatment / 대한신장학회잡지

BACKGROUND: We examined whether puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS) is associated with altered renal handling of water and sodium along with changes of renal abundance of aquaporins (AQP1 and AQP2) and NHE3. Next we tested the effects of alpha-melanocyte stimulating hormone (alpha- MSH), a potent anti-inflammatory drug, on the PAN-induced renal functional derangement and the changes of renal AQPs and NHE3 abundance. METHODS: PAN was administered to Sprague-Dawley rats using two protocols: protocol 1 (180 mg/kg, single iv injection) and protocol 2 (100 mg/kg, single iv injection). RESULTS: In both protocols, PAN-induced NS was associated with decreased urine concentration, manifested by an increased urine output and decreased urine osmolality and TcH2O. Consistent with this, a marked downregulation of vasopressin-regulated collecting duct AQP2 expression was seen in PAN-induced NS. In protocol 2 where rats treated with moderate dose of PAN, alpha-MSH cotreatment prevented the reduction of urine osmolality and the increase of the FENa in the PAN-induced NS. This suggests that alpha-MSH may have protective effects against the renal functional deterioration induced by PAN. The renal abundance of the AQP1, AQP2 and NHE3 was reduced in PAN-induced NS in protocol 2, as seen in protocol 1. In contrast to the functional improvement, alpha-MSH cotreatment had marginal effects in the prevention of renal AQP1, AQP2 and NHE3 downregulation in PAN-induced NS. CONCLUSION: PAN-induced NS was associated with decreased urine concentration along with reduced renal AQP2, AQP1 and NHE3 abundance. Alpha-MSH may have protective effects against the renal functional deterioration (e.g., urine osmolality and FENa). However, alpha-MSH treatment alone is less likely to prevent the marked reduction of AQP2, AQP1 and NHE3 abundance in PAN-induced NS, in contrast to the previously known dramatic effects against the ischemia-reperfusion injury in kidney and small intestine.

Silica Granuloma after Intermittent Intramuscular Injections: A Case Report

Most silica-contaminated wounds of the skin heal without complications. Cutaneous silica granuloma is a poorly understood, uncommon condition resembling a sarcoidosis. We report a case of silica granuloma after intermittent intramuscular injections. A 70-year-old man presented a painless mass in his right buttock for 2 weeks. He had received intermittent intramuscular injections of antihistamine drugs due to chronic dermatitis for 30 years. The histolopathological findings showed numerous hyalinized collagenous nodules with concentric layers, and an ill-defined chronic granulomatous inflammation containing foreign material. A polarized light microscopic examination revealed birefrigent particles. The presence of silica components was confirmed by scanning electron microscopy and energy dispersive X-ray microanalysis.

Expression of p16 and Rb in 9,10-Dimethyl-1,2-Benzanthracene Induced Rat Ovarian Carcinogenesis

BACKGROUND: In order to investigate the roles of p16 and Rb, their expression was evaluated in 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced ovarian cancers of rats. METHODS: DMBA-coated silk was inserted into both ovaries of 20 9-week-old Sprague-Dawley rats. The experimental period lasted 20 weeks. The tumor histology was classified and the expression of p16 and Rb in the ovarian tumors was analyzed by immunohistochemistry and Western blot. RESULTS: The p16 and Rb labeling index was significantly lower in the ovarian cancers than the normal ovarian surface epithelium of a rat. There were no differences among the cancer types. In Western blot analysis, the expressions of p16 and Rb in ovarian cancers were lower than those in normal ovarian tissue. No correlation was present between p16 and Rb. CONCLUSION: The abnormal expression of p16 and Rb occurs in DMBA-induced rat ovarian cancer and might be involved in carcinogenesis.

Asphyxia due to Oxygen Deficiency in the Cargo-hold Shipping Wood / 대한법의학회지

Oxygen deficiency has been frequent in a closed space. Wood consumes oxygen and discharges carbon dioxide instead of photosynthesis in closed space without light, so do some microorganisms on the surface. We experienced a case that a healthy insect-proofer fell down and died of asphyxia on stair-board at 7 m below the hatch of the cargo-hold shipping wood. Analysis of gases in cargo-hold revealed O2; 12.3%, CO; 105 ppm, CH4; 2.7%, and H2S; 1.9% at 1 m below the hatch, and then O2; 6.1%, CO; 220 ppm, CH4; 2.9%, and H2S; 2.3 ppm at 2.5 m below the hatch. Autopsy findings were unremarkable. We justiced the cause of death asphyxia due to oxygen deficiency. As seen in this case, the serious oxygen deficiency was accounted for oxygen consumption by wood and microorganisms.

Asphyxia due to Oxygen Deficiency in the Cargo-hold Shipping Wood / 대한법의학회지

Oxygen deficiency has been frequent in a closed space. Wood consumes oxygen and discharges carbon dioxide instead of photosynthesis in closed space without light, so do some microorganisms on the surface. We experienced a case that a healthy insect-proofer fell down and died of asphyxia on stair-board at 7 m below the hatch of the cargo-hold shipping wood. Analysis of gases in cargo-hold revealed O2; 12.3%, CO; 105 ppm, CH4; 2.7%, and H2S; 1.9% at 1 m below the hatch, and then O2; 6.1%, CO; 220 ppm, CH4; 2.9%, and H2S; 2.3 ppm at 2.5 m below the hatch. Autopsy findings were unremarkable. We justiced the cause of death asphyxia due to oxygen deficiency. As seen in this case, the serious oxygen deficiency was accounted for oxygen consumption by wood and microorganisms.

Expression of Cyclin D1 and CDK4 in DMBA-Induced Rat Ovarian Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Ovarian cancer is a common gynecologic malignancy and the leading cause of death in women. It is typically not diagnosed until it has reached the advanced stages. We performed this study to investigate the roles of the proteins related to the G1 cell cycle in ovarian carcinogenesis. MATERIALS AND METHODS: Immunohistochemistry and Western blot were used to analyse the expression of cyclin Dl and CDK4 in 7, 12-dimethylbenzanthracene- induced ovarian cancer in rats. RESULTS: The Cyclin D1 and CDK4 labelling index was significantly higher in the ovarian cancers than in the normal ovarian surface epithelium of rats. There was no difference among the cancer types. In Western blot analyses, the expression of cyclin Dl and CDK4 in the ovarian cancers was higher than that in the normal ovarian surface epithelium. A positive correlation was observed between the expressions of the CDK4 and Cyclin D1. CONCLUSION: The upregulation of cyclin Dl and CDK4 that occurs in DMBA-induced rat ovarian carcinogenesis is likely to be associated with tumor progression. Further studies are needed to investigate the role and function of cyclin Dl and CDK4 in human ovarian cancer.

Expressions of p53, bcl-2 Protein and Ki-67 Labelling Index and Their Relationships with Prognostic Factors in Prostate Cancer / 대한비뇨기과학회지

PURPOSE: The roles of genetic alterations in the p53 tumor suppressor gene and bcl-2 have been implicated in many types of human malignancies. We evaluated the significance of the expressions of p53 and bcl-2 and correlation with Ki-67 as prognostic factor in prostatic adenocarcinoma. MATERIALS AND METHODS: Immunohistochemical stain was performed for expression of p53 and bcl-2 using paraffin blocks of 22 cases of histologically confirmed prostatic adenocarcinoma and the results compared with the PSA, stage, grade, lymph node metastasis, Ki-67 labelling index (LI) and survival of the patients. RESULTS: Among 22 patients, 5 (22.7%) were positive for p53, and 7 (31.8%) were positive for bcl-2. Both bcl-2 and p53 positivity were found only in one (4.5%) patient. The p53 positivity correlated with high Gleason grade and Ki-67 LI but does not correlated with PSA, stage, or lymph node metastasis. The bcl-2 positivity was not correlated with PSA, stage, grade, lymph node metastasis, or Ki-67 LI. The p53 positivity correlated with poor survival but bcl-2 positivity was not correlated with survival. CONCLUSIONS: The p53 and bcl-2 were almost independently expressed in prostatic adenocarcinoma and may be involved in carcinogenesis. The p53 reactivity correlated with malignant phenotypes of prostatic adenocancinoma and poor survival and appears to be an independent prognostic indicator.

Expression of Cyclin D1, Cyclin E, p21Cip1 and p27Kip1 in Chemically Induced Rat Mammary Tumor Treated with Tamoxifen and Transforming Growth Factor-1

BACKGROUND: Tamoxifen (TAM) inhibits the action of estrogen by binding to estrogen receptors, and also has non-estrogen receptor mediated cytostatic activities. Transforming growth factor-1 (TGF-1) inhibits the proliferation of many other cell types, such as epithelial, hematopoietic and endothelial cells. METHODS: We investigated the effects of tamoxifen on the growth of 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumors and the expression of cyclin D1, cyclin E, p21Cip1, and p27Kip1 by performing immunohistochemistry and Western blot analysis, and studied whether TGF-1 injection amplified the effects of TAM. When tumor size reached between 10-15 mm in the largest dimension, the rats were divided into 3 groups: DMBA-control group (n=12), DMBA-TAM group (n=14) and DMBA-TAM plus TGF-1 group (n=5). RESULTS: The consecutive administration of TAM markedly decreased the tumor development compared with the DMBA-control group. The DMBA-TAM and DMBA-TAM plus TGF-1 groups showed decreased expression of bromodexoyuridine, cyclin D1, cyclin E, and p21Cip1 when compared with those of the DMBA-control group. On the other hand, the labeling index of p27Kip1 was higher in the DMBA-TAM plus TGF-1 group than in the DMBA-control group. CONCLUSION: TAM suppresses tumor development, which may be associated with down-expression of cyclin D1 and cyclin E, and overexpression of p27Kip1, and addition of TGF-1 does not influence tumor development treated by TAM.

Histopathologic Change and Apoptotic Profile in Basal Ganglia of Rat Induced by Manganese Administration

Mn (manganese) is known to induce Parkinsonian neurological disorder. Several lines of evidence suggest that apoptosis is involved not only in physiological cell death during normal development but also in neurodegenerative disease. The mechanism of Mn induced cell death remains poorly understood. In the present study, we evaluated the morphologic changes and apoptotic profile in basal ganglia using rat model of Mn toxicity. The rats were divided into three groups: the first group was a control; the second group was subdivided by administration dosage of Mn into group A (5, 10 mg MnC12/ kg) and group B (20, 40 mg MnC12/kg). The rats of each subgroup received a injection of Mn via tail vein every week for 4 weeks. The second group received 4 repeated injection of 10 mg MnC12/kg in the same manner and the rats were sacrificed at day 1, 3 & 7 in group I and at day 10, 21, 42, and 90 in group II after the last injection. A significant loss of neuron and gliosis were observed in the basal ganglia in the experimental groups (p<0.05), which were more pronounced in group II than in the control or group I. No significant difference in number of nerve cells or degree of gliosis was identified in the substantia nigra. Apoptotic cells were also increased in basal ganglia of experimental groups and appeared among neurons (10%), glial cells (10%), and endothelial cells (60%). Apoptotic figures were consistently noted through the entire experimental period after Mn injection in basal ganglia. In conclusion, these results demonstrate that Mn-induced cytopathic insult affects various cell types in basal ganglia and shows variable sensitivity in the different regions of brain, especially in the apoptotic cell death of the neuron. The overaccumulation of Mn in the brain might be attributed from the breakdown of blood-brain barrier due to the injury through the apoptosis.

Expression of p27Kip1 Protein in Carcinoma of the Urinary Bladder

The cyclin-dependent kinase (cdk) inhibitor p27Kip1 gene is a powerful molecular determinant of cell cycle progression. Loss of expression of p27Kip1 has recently been shown to be predictive of disease progression in several human malignancies. The prognostic value and expression of p27Kip1 have been incompletely studied in bladder cancer. In this study, we investigated the relationship between p27Kip1 protein expression and clinicopathologic parameters in 50 cases of carcinoma of the urinary bladder by conducting immunohistochemical analysis and DNA flow-cytometry. Malignant bladder tissue demonstrated a heterogeneous pattern of p27Kip1 immunoreactivity. In addition, there was progressive loss of expression with increasing tumor grade. The expression of p27Kip1 protein was unrelated to stage, DNA ploidy and S phase fraction (SPF). SPF was unrelated with tumor grade and DNA ploidy. The results indicate that p27Kip1 is frequently expressed in well differentiated transitional cell carcinomas of the urinary bladder but less often expressed in muscle-invasive transitional cell carcinomas. The expression of p27Kip1 and its prevalence in low-grade tumors may reflect growth regulatory influences and potential inhibiting action in tumor progression and novel predictive markers of the biological potential of bladder tumors.

Expression of p21(waf1/cip1) Protein in Bladder Cancer and its Prognostic Value / 대한비뇨기과학회지

No abstract available.

Imprint Cytologic Features of Fibroadenoma of the Breast with Extensive Infarction: A Case Report / 대한세포병리학회지

Spontaneous Infarction of fibroadenoma of the breast is very uncommon and may lead to difficulties in clinical and pathological diagnosis. Most reported cases occured in young women during pregnancy or lactation. This report describes imprint cytologic features of an infarcted fibroadenoma in a 19-year-old young woman without evidence of pregnancy. The smears revealed many individually scattered degenerated or necrotic epithelial or spindle stromal cells and naked nuclei on dirty necrotic background. A few sheets of cohesive uniform epithelial cells and a few fragments of stromal cells were also present. Most of the epithelial cells had pyknotic and hyperchromatic nuclei, however, cellular atypism such as pleomorphism, prominent nucleoli or mitosis were not present. Though the necrotic ductular and glandular outline of this case may bear a superficial resemblance to adenocarcinoma, obvious cytologic atypia or mitosis, even in the necrotic areas, were not present.

Button battery impaction in nasal cavity

A button battery inserted in the nose of children is an unusual foreign body which is capable of causing extensive tissue damage, resulting from electrical and chemical burns. We report a case of button battery in the nose of a 4-year-old boy presenting with unilateral nasal discharge, and necrosis in the septum and turbinate of the right nasal cavity. Mercury level in concentrated urine was within normal limit. Microscopic examination disclosed extensive liquefaction necrosis with calcification and fibrosis. Numerous dark brown to black granules were noted in the elastic and collagen fibers and interstitium. Dark-field examination of the section revealed brilliantly refractile granules. Polarized microscopy failed to show the granules. Most brown pigments reacted to prussian blue. Tissue mercury analysis yielded a mercury content of 8.01 ppm. We report this case to emphasize the hazards of button battery impaction and to draw attention to the significance of the problem through histopathologic examination.

Manganese Intoxication in the Rat A neuropathologic study and distribution of manganese in rat brain

We investigated a topographical distribution of managanese, and immunohistochemical density of tyrosine hydroxylase (TH), and histopathologic findings in globus pallidus and substantia nigra according to manganese dose and time course in the brain of rats which received MnCl2 intravenously. Topographical distribution of manganese was also investigated after injection of FeCl2. The manganese concentrations of brain in control and experimental group were highest in pituitary gland and thalamus, and lowest in the cerebral cortex. The manganese concentration of blood was increased proportionally to the dose administered, and the biological half-life of blood manganese was between 21 and 42 days. The manganese concentrations of brain were increased proportionally to the dose, and increase rate was highest in olfactory bulb, and the biological half-lives of brain manganese ranged from 42 days to 90 or more days; the longest were observed in pituitary gland, medulla oblongata and cerebral cortex. In case of administration of FeCl2, the manganese concentrations of brain were higher than that of control group in dose of 2.5 mg/kg, and decreased proportionally to the administered dose, resulting in lower level compared with control group in high dose of FeCl2 administered. Significantly decreased number of nerve cell and increased gliosis in globus pallidus were observed in experimental group, which were closely correlated with the duration after manganese injection, but no significant change of number of nerve cell expressing TH and gliosis were observed in substantia nigra. Density of immunohistochemical reaction for TH in globus pallidus made little difference between control and experimental group. These results suggest that pathology of manganese intoxication is caused by the loss of nerve cells in globus pallidus, and closely correlated with the duration after manganese exposure.

Prognostic Value of TGF-beta1, TGF-beta2 Expression and Ki-67 Labelling Index in Prostate Cancer / 대한비뇨기과학회지

PURPOSE: Transforming growth factor-beta(TGF-beta) is a potent modulator of cell proliferation, differentiation, angiogenesis and immune system. We evaluate the significance of the expression of TGF-beta1 and TGF-beta2 and correlation with Ki-67 as prognostic factors in prostate cancer. MATERIALS AND METHODS: In order to investigate the expression of TGF-beta1, TGF-beta2 and Ki-67, we analyzed immunohistochemical staining from paraffin blocks of 22 cases of the prostate carcinoma and adjacent normal prostate. RESULTS: The TGF-beta1 staining scores of the tumor cells were higher than those of the adjacent normal epithelial cells(p=0.001). The TGF-beta2 staining scores of the tumor cells were also higher than those of the adjacent normal epithelial cells(p=0.003). However no correlation was observed between tumor surrounding stroma and normal stroma in TGF-beta1 and TGF-beta2 staining scores. The serum PSA level, the clinical stage, the Gleason score and the lymph node metastasis of the tumor was not correlated with the staining score of TGF-beta1 and TGF-beta2. Ki-67 labelling index(LI) was significantly associated with the histologic grade, while no relationship was observed between Ki-67 LI and clinical stage. TGF-beta1 and TGF-beta2 staining score was not statistically correlated with the Ki-67 LI. CONCLUSIONS: These results indicate that the prostatic cancer was associated with alteration of TGF-beta1 and TGF-beta2 expression by prostatic epithelial cells which may be biologically important in the development of prostate cancer and TGF-beta1 and TGF-beta2 expression may be new target of treatment of prostate cancer. Prognostic value of TGF-beta1 and TGF-beta2 expression was not statistically significant but Ki-67 LI was significantly associated with Gleason score.

Castration-induced Apoptosis in the Rat Prostate

This study was carried out to investigate the morphologic findings and process of castration-induced apoptosis in the rat prostate. The experimental group was treated with bilateral orchiectomy followed by sequential sacrifices at 1, 2, 3, 4, 5, 6, 7 days and 2, 3 weeks (6 rats, respectively). Ventral prostate was extirpated and examined by light microscopic and immunohistochemical, ultrastructural observation. Apoptotic index increased by 4 days after castration and decreased thereafter. ApopTag stain revealed brownish granular pattern in the nucleus of apoptotic cells. DNA fragmentation rate was 0.5% in the control group and began to increase by 1 day after castration and reached to 11.1% by 4 days and decreased thereafter. PCNA stain showed brownish granular pattern in the nucleus of some epithelial cells of the prostatic glands. PCNA labelling index was 2.4% in the control group and reached peak by 3 days after castration and decreased thereafter. Electron microscopically, there was chromatin condensation with margination toward the nuclear membrane by 1 day after castration. Also noted were condensation of cytoplasm, dilatation of RER and nuclear fragmentation. Apoptotic bodies were formed and phagocytosed by adjacent cells and some apoptotic bodies were found in the lumen of acini. Based on these results, it can be concluded that castration-induced prostatic involution is the result of apoptosis. Detection of DNA fragmentation with ApopTag is a more a accurate method to identify not only apoptotic body formation itself but also the previous step of apoptotic body formation. PCNA labelling index to identify the cellular proliferation seems to play an active role in the early step of apoptosis and be a good tool for investigation of apoptosis.