Clinical characteristics and management of orbital apex syndrome: a 10-year multicentre experience.

BACKGROUND: Orbital apex syndrome (OAS) is a condition characterised by lesions within the orbital apex, leading to various ophthalmologic symptoms. This study aimed to analyse the clinical characteristics and treatment strategies of OAS with respect to aetiology. METHODS: This retrospective analysis utilised data from 5 medical institutions between 2013 and 2022. Patients who were diagnosed with OAS were initially enrolled, but patients who failed to follow up at least 1 month were excluded. The prevalence of initial ophthalmologic symptoms and visual improvement after treatment was compared according to aetiology. Factors related to visual improvement were analysed. RESULTS: Among 73 enrolled patients, the leading aetiology was tumours, followed by fungal infections and inflammation. Visual impairment and proptosis were prevalent in tumour-related OAS cases. Inflammation-related OAS exhibited a higher likelihood of painful eye movements and ophthalmoplegia. Ptosis was most frequently observed in fungal infection-related OAS. Notably, fungal infections emerged as the sole significant factor negatively impacting vision progression. In inflammation-related OAS, the time interval between symptom onset and the administration of steroids was longer in patients without visual improvement, even though there was no statistically significant difference. CONCLUSIONS: Tumours were the predominant cause of OAS. Visual impairment was a common manifestation in tumour-related OAS, while fungal infections were strongly associated with a poor visual prognosis. The timely administration of steroids might be helpful for improving vision in patients with inflammation-related OAS. However, further studies are needed to enhance understanding and management of OAS.

Nestin expression as an indicator of cervical cancer initiation.

Nestin is an intermediate filament protein expressed in proliferating cells during embryonic development of the central nervous system (CNS) and considered to be a neuronal stem cell/progenitor cell marker. This study investigated the difference of nestin expression between pre-cancer (carcinoma in situ - CIS) and cancer of cervix in 129 tissues (49 normal cervix, 41 CIS, and 39 invasive cervical cancer) through the use of a paraffin-embedded tissue array. Immunostaining was evaluated by intensity, proportion of stained cells, and pattern of expression. The expression of nestin was positive in 63.4% (26/41) for CIS and 43.6% (17/39) for invasive cervical cancer, but only 26.5% (13/49) for normal tissues (p = 0.002). Strong positive staining/large proportion staining were 53.7% (22/41) / 36.6% (15/41), 15.4% (6/39) / 61.5% (24/39) in the CIS and invasive cervical cancer tissues, respectively (p = 0.043, p < 0.001). The diffuse stain with basal layer was positive in 90.2% (37/41) for CIS, but only 24.5% (12/49) of the samples were positive in normal tissues (p < 0.001). Based on these results, the authors suggest that nestin expression seems to participate in the step of cancer initiation and could potentially be a useful marker in the early detection of cervical cancer.

A sperm GPI-anchored protein elicits sperm-cumulus cross-talk leading to the acrosome reaction.

The acrosome reaction has long been thought to be induced by the zona pellucida. Here we report the identification and function of a novel human sperm glycosylphosphatidylinositol (GPI)-anchored membrane protein, NYD-SP8. The release of the protein during sperm-egg interaction and its binding to the cumulus, the first layer of egg investment, elicits cross-talk between the gametes and produces calcium dependant release of progesterone, which lead to the acrosome reaction. An in vivo mouse model of NYD-SP8 immunization is also established showing a reduced fertility rate. Thus, contrary to accepted dogma, our study demonstrates for the first time that, prior to reaching the zona pellucida, sperm may release a surface protein that acts on the cumulus cells leading to the acrosome reaction, which may be important for determining the outcome of fertilization.

An antimicrobial peptide gene found in the male reproductive system of rats.

Little is known about the innate defense mechanisms of the male reproductive tract. We cloned a 385-base pair complementary DNA and its genomic DNA named Bin1b that is exclusively expressed in the caput region of the rat epididymis and that is responsible for sperm maturation, storage, and protection. Bin1b exhibits structural characteristics and antimicrobial activity similar to that of cationic antimicrobial peptides, beta-defensins. Bin1b is maximally expressed when the rats are sexually mature and can be up-regulated by inflammation. Bin1b appears to be a natural epididymis-specific antimicrobial peptide that plays a role in reproductive tract host defense and male fertility.

Lactobacillus casei prevents the development of dextran sulphate sodium-induced colitis in Toll-like receptor 4 mutant mice.

Probiotics, defined as live or attenuated bacteria or bacterial products, confer a significant health benefit to the host. Recently, they have been shown to be useful in the treatment of chronic inflammatory bowel disease and infectious colitis. In this study, we investigated the effect of probiotics on the development of experimental colitis using Toll-like receptor 4 (TLR-4) mutant (lps-/lps-) mice. TLR-4(lps-/lps-) and wild-type (WT) mice were given 2.5% dextran sulphate sodium (DSS) in drinking water to induce colitis with or without Lactobacillus casei pretreatment. Clinical and histological activity of DSS-colitis was attenuated markedly both in TLR-4(lps-/lps-) and WT mice pretreated with L. casei. Interestingly, histological activity was less severe in TLR-4(lps-/lps-) mice than in WT mice. The levels of myeloperoxidase activity and interleukin (IL)-12p40 were attenuated in pretreated TLR-4(lps-/lps-) mice after DSS administration. By contrast, transforming growth factor (TGF)-beta and IL-10 mRNA and protein expressions were increased markedly in pretreated TLR-4(lps-/lps-) mice. The current results suggest that L. casei has a preventive effect in the development of acute DSS-induced colitis and its action depends largely upon TLR-4 status. L. casei modulates the expression of inflammatory cytokines and down-regulates neutrophilic infiltration in the case of incomplete TLR-4 complex signalling.

Tacrolimus-Induced Apoptosis is Mediated by Endoplasmic Reticulum-derived Calcium-dependent Caspases-3,-12 in Jurkat Cells.

Apoptotic signal pathways are delivered to caspase-3, caspase-9, or both in different cells via the death receptor pathway, mitochondrial pathway, or by the endoplasmic reticulum (ER) pathway through initiators of caspase-3, -8, -9, or -12. Tacrolimus (Tac)-induced apoptosis was characterized by nuclear fragmentation and caspase-3 activation. We examined the effect of tacrolimus on ER-derived calcium and caspase-3,-12-mediated apoptosis on Jurkat human T lymphocyte. Tac decreased the viability of Jurkat cells in a dose-dependent manner. Tac also increased continuously intracellular concentration of calcium from 24 hours to 72 hours. We did not find intracellular calcium changes on the treatment of calcium ionorpore (A23187) regardless of 1 nmol/L Tac concentration level. However, calcium adenosine triphosphatase inhibitor (thapsigargin) increased intracellular calcium accumulation and co-treating 1 nmol/L Tac further induced intracellular calcium accumulation. Interestingly, we found that 1 nmol/L Tac treatment induced activation of caspase-12 protease as well as the catalytic activity of caspase-3 but not catalytic activation of caspase-6, -8, and -9 proteases in Jurkat cells. These data advance our understanding of Tac-induced apoptosis is ER-derived calcium and caspases-3,-12- mediated apoptosis in human Jurkat cell line.

Patient factors predictive of pain and difficulty during sedation-free colonoscopy: a prospective study in Korea.

BACKGROUND: Successful colonoscopy depends on insertion of the instrument to the cecum, precise observation, and minimal patient discomfort during the procedure. This prospective study was designed to identify factors, apart from the endoscopist's skill, that predict patient pain and technical difficulty during sedation-free colonoscopy. METHODS: A total of 426 sedation-free colonoscopies performed by one experienced endoscopist were evaluated in a prospective manner. Factors were recorded, including patient pain level, intubation time, demographic data, history of abdominal surgery, bowel preparation status, diverticular disease, bowel habits, anxiety level, and number of previous colonoscopies. These factors were analysed to determine their association with difficulty and pain during the procedure. RESULTS: Four hundred six colonoscopies were completed to the cecum (95.3%). Mean insertion time for complete colonoscopy was 6.5+/-3.5 min. Multivariate logistic regression analyses revealed that older age, lower body mass index, previous hysterectomy, diarrhoea, 1st time colonoscopy and anxiety were predictors of patient pain. Older age, lower body mass index and previous hysterectomy were predictors of difficulty of intubation. CONCLUSIONS: This prospective study identified several factors that may predict patient pain and technical difficulty associated with the procedure. These findings have implications for the practice and teaching of colonoscopy.

Evidence for an age-related attenuation of cerebral microvascular antioxidant response to oxidative stress.

Effects of aging and oxidative stress were studied in cerebral microvessels and microvessel-depleted brain from 6-, 18-, and 24-month-old C57Bl/6J mice exposed to normoxia, 24 or 48 h hyperoxia, or 24 h hyperoxia followed by 24 h normoxia. Microvessels lacked smooth muscle and consisted predominantly of endothelium. Following exposure and isolation of microvessel and parenchymal proteins, Western blot analysis was performed for detection of cytosolic thioredoxin 1 (TRx 1) and mitochondrial thioredoxin 2 (TRx 2), protein carbonyl, and mitochondrial superoxide dismutase (MnSOD). Both microvessel and parenchymal TRx 1 levels were increased by hyperoxia; however, the microvascular response was limited and delayed in comparison to that of the parenchymal fraction. Whereas TRx 2 levels in microvessels were increased in older mice, irrespective of exposure condition, hyperoxia per se had little or no apparent effect. Parenchymal cells showed no age-related increase in TRx 2 level under normoxic conditions, but showed increased levels following hyperoxia. Microvessel MnSOD was lower than that in parenchymal cells, but increased with age under normoxia, and also was correlated with the duration of hyperoxia. Although hyperoxia augmented MnSOD levels in young (6 months) and middle-aged (18 months) animals, the response was less pronounced in microvessels from senescent, 24-month-old mice. Unlike microvessels, which showed a sustained age-related increase in MnSOD level under each exposure condition, parenchymal cells from normoxic mice showed no increase, and hyperoxia-induced elevations declined with prolonged 48 h exposure. These results indicate that the microvessel endothelium is (1) subjected to a more intense oxidative environment than neurons and glia and (2) is limited by aging in its ability to respond to oxidative insult.

Huge gastric diospyrobezoars successfully treated by oral intake and endoscopic injection of Coca-Cola.

A diospyrobezoar is a type of phytobezoar that is considered to be harder than any other types of phytobezoars. Here, we describe a new treatment modality, which effectively and easily disrupted huge gastric diospyrobezoars. A 41-year-old man with a history of diabetes mellitus was admitted with lower abdominal pain and vomiting. Upper gastrointestinal endoscopy revealed three huge, round diospyrobezoars in the stomach. He was made to drink two cans of Coca-Cola every 6 h. At endoscopy the next day, the bezoars were partially dissolved and turned to be softened. We performed direct endoscopic injection of Coca-Cola into each bezoar. At repeated endoscopy the next day, the bezoars were completely dissolved.

Association of obesity, serum glucose and lipids with the risk of advanced colorectal adenoma and cancer: a case-control study in Korea.

BACKGROUND: Previous studies on colorectal cancer risk suggest that obesity, serum lipids and glucose might be related to colorectal carcinogenesis. This case-control study was conducted to investigate the association between obesity, serum lipids and glucose, and the risk of advanced colorectal adenoma and cancer. METHODS: Patients with histologically confirmed colorectal cancers (n=105), same number of patients with advanced colorectal adenomas matched by age and sex, and the same number of controls matched by age and sex were selected in Hanyang University Guri Hospital between January 2002 and June 2004. RESULTS: Adenoma and cancer group showed significantly higher levels of mean body mass index and serum glucose. Cancer group also showed significantly lower mean serum lipids levels than controls. We used an unordered polytomous logistic model to calculate multivariate odds ratios for advanced adenoma and cancer relative to controls. Higher serum glucose level was more strongly associated with increased risk of cancer relative to controls (odds ratio, 3.0; 95% confidence interval, 0.9-9.8) than with increased risk of advanced adenoma (odds ratio, 2.1; 95% confidence interval, 0.9-5.4). Higher body mass index was strongly associated with increased risk of advanced adenoma (odds ratio, 10.8; 95% confidence interval, 4.6-25.3), but associated with attenuated risk of cancer (odds ratio, 2.3; 95% confidence interval, 0.9-5.8). Serum triglycerides and cholesterol levels were strongly associated with reduced risk of cancer (odds ratio, 0.3; 95% confidence interval, 0.1-0.8 and odds ratio, 0.2; 95% confidence interval, 0.1-0.6, respectively). CONCLUSIONS: Obesity and hyperglycaemia are positively related to advanced colorectal adenoma formation. Furthermore, hyperglycaemia plays an important role in progression to cancer. Findings on an inverse relationship between serum triglyceride and cholesterol levels and the risk of colorectal cancer may be the secondary results from metabolic or nutritional changes in advanced colorectal cancer patients and should be clarified in further studies.

Expression of Endoplasmic Reticulum-Mediated Stress Proteins in FK506-Treated T-Lymphocytes.

BACKGROUND: FK506-induced apoptotic endoplasmic reticulum (ER)-mediated stress protein expression was investigated in Jurkat human T-lymphocytes. METHODS: The effect of FK506 on apoptosis and cell viability were examined. FK506-induced apoptosis was confirmed by nuclear fragmentation after DAPI staining. Expression of apoptotic ER-mediated stress proteins was examined by means of Western blotting of Grp78/BiP, Grp94, double-stranded RNA-dependent protein kinase (PKR)-like ER kinase (PERK), phosphor-PERK, CHOP/GADD153, and Bak. A flow cytometry analysis was performed after DAF-DA or DCF-DA staining. FK506-induced apoptosis was dose-dependent (10 nmol/L) and time-dependent (72 hours). RESULTS: Grp78/BiP and Grp94 expressions were increased 36 hours after FK506 treatment. Increased phospho-PERK expression was observed 6 hours after FK506 treatment and peak activation of phospho-PERK was observed at 36 hours. CHOP/GADD153 expression was increased 48 hours after FK506 treatment. Expression of iNOS after FK506 treatment began to increase at 12 hours, peaked at 24 hours, and decreased after 36 hours. CONCLUSIONS: From these results, we confirmed that FK506 induces apoptosis and acts dose- and time-dependently to decrease the viability of Jurkat cells through activation of apoptosis signaling and expression of apoptotic ER-mediated stress proteins.

Functional expression of sperm angiotensin II type I receptor in Xenopus oocyte: modulation of a sperm Ca2+-activated K+ channel.

In addition to Ca2+ and K+ fluxes, angiotensin II (Ang II) has been shown to influence sperm motility. The present study investigated the involvement of angiotensin II type 1 receptor (AT1) in mediating the modulatory effect of Ang II on a sperm Ca2+-activated K+ channel expressed in Xenopus oocytes injected with RNAs of spermatogenic cells. Ang II at a concentration of 1 microM was found to potentiate the ionomycin-induced current, previously demonstrated to be mediated by a 'Maxi' Ca2+-activated K+ channel. However, at higher concentration, 20 microM, Ang II was found to suppress the ionomycin-induced current. Both potentiating and inhibitory effects of Ang II were blocked by losartan, a specific antagonist of AT1 receptors. Immunohistochemical studies further confirmed the presence of AT1 receptors in spermatogenic cells while expression of AT1 receptor mRNA was demonstrated by RT-PCR. These results suggest that Ang II may influence sperm motility as well as other sperm function by acting on AT1 receptors, and exerting potentiating and inhibitory effects on the Ca2+-activated K+ channels.

Functional expression of a Ca2+-activated K+ channel in Xenopus oocytes injected with RNAs from the rat testis.

The present study investigated the feasibility of using Xenopus oocytes to express sperm ion channel by injection of RNAs extracted from the rat testis. The RNA-injected oocytes expressed an outwardly rectifying current which was dependent on K+ concentration and inhibitable by K+ channel blockers, charybdotoxin (CTX) and tetraethylammonium (TEA). The Ca2+ ionophore, ionomycin, could also stimulate current activation with similar current characteristics in the RNA-injected oocytes, suggesting the expression of a Ca2+-activated K+ channel. Immunolocalization indicated predominant Ca2+-activated K+ channel immunoreactivity associated with spermatogenic cells. Reverse transcriptase-polymerase chain reaction studies confirmed the expression of the Ca2+-activated K+ channel mRNA in isolated spermatogenic cells. Our results suggest that ion channels and/or receptors of spermatogenic cells could be investigated using the Xenopus oocyte as an expression system. The present study also suggests that sperm may possess a Ca2+-activated K+ channel which has been implicated in the process of sperm activation and gamete interaction.

Transcriptional activation of nuclear-related factor 2 by FK506 in Jurkat T cells.

BACKGROUND: We investigated the effect of FK506 in transcriptional activation of nuclear factor (erythroid-derived 2)-like2 (Nrf2) in human Jurkat T cells. METHODS: FK506 treatment increased the generation of reactive oxygen species and reactive nitrogen species in Jurkat cells in a dose-dependent manner. Generation of nitric oxide was also increased after treatment with FK506 in Jurkat cells. Peak levels of endothelial nitricoxide synthase expression occurred at 24 hours and then decreased after 48 hours. RESULTS: We found that a marked dissociation of Nrf 2 from Kelch-like ECH-associated protein-1 and subsequently Nrf 2 nuclear translocation occurred in Jurkat cells treated with FK506 during 48 hours. Immunohistochemistry and Western blot analysis data revealed that the FK506 treatment increased expression of heme oxygenase-1 (HO-1) in Jurkat cells in a dose-dependent manner. HO-1 expression was induced after 6 hours of treatment of FK506 to Jurkat cells, peaked at 24 hours, and then decreased after 48 hours. CONCLUSIONS: These results suggest that FK506 induces Nrf 2-driven transcriptional activation of the antioxidant response element by activating HO-1 and free radicals such as reactive oxygen species and nitric oxide.

Expression of sperm Ca2+-activated K+ channels in Xenopus oocytes and their modulation by extracellular ATP.

Ionic fluxes across the sperm membrane have been shown to be important in the initiating process of sperm activation and gamete interaction; however, electrophysiological investigation of the ion channels involved has been precluded by the small size of the sperm, especially in mammalian species. In the present study sperm ion channels were expressed in Xenopus oocytes by injection of RNAs of spermatogenic cells isolated from the rat testes. The RNA-injected oocytes responded to ATP, a factor known to regulate sperm activation, with the activation of an outwardly rectifying whole-cell current which was dependent on K+ concentrations and inhibitable by K+ channel blockers, charybdotoxin (CTX) and tetraethylammonium (TEA). The ATP-induced current could be mimicked by a Ca2+ ionophore but suppressed by a Ca2+ chelator applied intracellularly, indicating a Ca2+ dependence of the current. Single-channel measurements on RNA-injected oocytes revealed channels of large conductance which could be blocked by CTX and TEA. Co-injection of germ cell RNAs with the antisense RNA for a mouse gene encoding slowpoke 'Maxi' Ca2+-activated K+ channels resulted in significant reduction of the ATP- and ionomycin-induced current. The expression of the 'Maxi' Ca2+-activated K+ channels in sperm collected from the rat epididymis was also confirmed by Western blot analysis. These results suggest that sperm possess Ca2+-activated K+ channels which may be involved in the process of sperm activation.

Relation of Fos-IR expression in the pelvic ganglion to sexual behavior in laboratory rats.

The pelvic ganglion (PG) provides both sympathetic and parasympathetic innervation to the genitalia and other pelvic structures. To determine whether neuronal activity; of the PG, as detected by Fos-like immunoreactivity (Fos-IR), is related to sexual stimulation, male and female rats were tested under a variety of conditions. In males, Fos-IR expression in the PG was positively correlated with the amount of both genital and noncontact stimulation. In females, only ejaculation preceded by multiple intromissions induced a significant increase in Fos-IR; multiple intromissions or ejaculation preceded by only 0-1 intromission did not affect Fos-IR. Additional experiments comparing Fos-IR expression, in which some females were allowed to pace their sexual contact and others were not, revealed that ejaculation duration was the key factor in the induction of Fos-IR in female rats. Because the conditions under which Fos-IR expression occurred in females are identical to those required for sperm transport, we suggest that, in the female, sperm transport is regulated in part by autonomic outflow from the PG after copulation. These relations between sexual behavior and measures of PG activity are consistent with the idea that the sexually dimorphic organization of the peripheral nervous system plays a major role in mediating the gender-specific outcome of copulation: ejaculation in the male and sperm transport in the female.

Fetal mouse selenophosphate synthetase 2 (SPS2): biological activities of mutant forms in Escherichia coli.

A novel gene, sps2, detected in mouse embryo at the early stages of development has been identified as an analog of the E. coli selenophosphate synthetase gene. Unlike the E. coli enzyme, the presence of selenocysteine in the mouse enzyme is indicated by a TGA codon in the open reading frame of the cDNA. Using an N-FLAG monoclonal antibody, it was shown that the full length N-FLAG-sps2 gene product was expressed in COS-7 cells. To investigate the biological activity of the sps2 gene product in vivo, the mutated sps2 gene, which contains cysteine in the place of the TGA encoded selenocysteine in the wild type, was expressed in the E. coli selD deficient mutant, MB08. Like the E. coli wild type selD gene, the mutant sps2 gene complemented the selD mutation. However, replacement of Cys with either Ala, Ser, or Thr resulted in a loss of ability to complement the selD mutation. The SPS2-CYS protein expressed in E. coli was purified and its catalytic activity was determined. The Km value for ATP was 0.75 mM and Vmax was 9.23 nmole/min/mg protein. These results confirm that the mouse embryonic sps2 gene encodes an eukaryotic selenophosphate synthetase, and that availability of selenophosphate as a selenium donor compound is widespread.

Effects of neonatal polychlorinated biphenyl exposure on female sexual behavior.

The effects of polychlorinated biphenyls (PCBs) on development and reproduction are well documented. However, very little is known about the effects of PCBs on sexual behavior. In this study, we examined the effects of two commercial PCB mixtures, Aroclor 1221 (A1221) and Aroclor 1254 (A1254), on the development of female sexual behavior and of the incertohypothalamic dopaminergic cells (A11 and A13) in Long-Evans rats. Neonatal exposure to A1254 significantly reduced sexual receptivity and reduced the female's latency to approach a male after an intromission. Neonatal treatment with A1221 did not affect female sexual behavior nor did treatment of adult females with A1221 or A1254. Since sexual behavior is affected by dopamine and since PCBs have been reported to alter dopamine content in the brain, we examined the effects of A1221 or A1254 on dopaminergic cells in the incertohypothalamic region of neonatally exposed rats. None of the treatments significantly affected the number of A11 or A13 neurons that were immunoreactive for tyrosine hydroxylase (TH) or the expression of Fos (i.e., the product of the immediate early gene c-fos) in these dopaminergic neurons. Therefore, the disruption of behavior induced by neonatal treatment with A1254 does not appear to be mediated by toxic effects of the mixture on incertohypothalamic dopaminergic systems.

The proximity of the lesion to cell bodies determines the free radical risk induced in rat rubrospinal neurons subjected to axonal injury.

To find out whether close axonal injury resulted in greater free radical risk to cord-projection central neurons than distant ones, we studied the expressions of nitric oxide synthase, calcineurin, and superoxide dismutase in rat rubrospinal neurons following brainstem, C2 and T10 axotomies using immunohistochemical methods. We found that nitric oxide synthase expression was upregulated more following brainstem than C2 lesion while T10 lesion triggered no detectable changes. This response peaked at 1 week and returned to control level by 8-week-post-injury. At the same time, calcineurin, which activated nitric oxide synthase, was increased 1 week following brainstem and C2 axotomies. These suggest that close, but not distant, axotomy enhanced NO production, which appeared to be cytotoxic since blocking NO synthesis with N-nitro- l-arginine methyl ester reduced brainstem axotomy-induced rubrospinal cell loss. On the other hand, the mitochondrial Mn-superoxide dismutase, which competes with NO to prevent the formation of the cytotoxic free radical peroxynitrite, was notably reduced after brainstem but almost unaltered following C2 axotomy. Meanwhile, the cytosolic Cu/Zn-superoxide dismutase was not altered following C2 but increased after brainstem axotomy. Ultrastructurally, in rubrospinal neurons more mitochondria became swollen following brainstem than C2 axotomy. Based on these, we proposed that besides the NO-overproduction-induced toxicity, superoxide-loading-induced mitochondrial damage also added to hampering the survival of the closely axotomized neurons.

Dynamic evaluation of absorbed dose to the bladder wall with a balloon-bladder phantom during a study using [(18)F]fluorodeoxyglucose positron emission imaging.

An accurate evaluation of the absorbed dose to the bladder wall from 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) is clinically important because the bladder is considered as a critical organ in most positron emission tomography (PET) studies that cumulate about 20% of the total activity injection during image procedures. In the MIRD calculation, no allowance is made for the inclusion of all the dynamic parameters that affect the actual dose to the bladder wall to be taken in the dose assessment. The goal of the study is to propose a dose evaluation model by using a dynamic bladder phantom and time-activity curves from the bladder PET imaging. The proposed model takes all dynamic parameters into account and provides a much more accurate dose estimation to the bladder. In this study, the lowest dose to the bladder wall was obtained at the conditions of having a larger initial volume for the bladder contents and a higher production rate for urine. It is then advised patients to drink a bulk amount of water before the FDG injection or after urine voiding to facilitate urine production and to enlarge the bladder surface area, which are the most crucial steps in reducing the dose to the bladder wall. In our study, the voiding schedule in dose calculation plays certain roles although it is much more critical in the conventional MIRD calculation. The model estimated that the lowest dose to the bladder would occur at an initial void about 40 min after the FDG injection and the urine voiding was as complete as possible.