Combined estrogen and ghrelin administration decreases expression of p27<Superscript>kip1</Superscript> and proportion of isomyosin type I in the striated urethral and anal sphincters and levator ani of old ovariectomized rats

We compared estrogen and/or ghrelin effects on pelvic floor muscles in old versus young adult ovariectomized rats. Ovariectomized Fisher 344 rats (18 and 3 months old, n = 24 x 2) received 42 daily intraperitoneal 17-beta estradiol (10 mug kg(-1)), ghrelin (2 mug kg(-1)), both, or vehicle (n = 6 x 4/group). Cytoplasmic p27(kip1) expression and isomyosin I proportion in striated urethral and anal sphincters and levator ani were measured, respectively, by Western blot analysis and gel electrophoresis with immunohistochemistry of muscle ghrelin receptors and radioimmunoassay of circulating growth hormone. In young adult rats, estrogen significantly decreased cytoplasmic p27(kip1) and isomyosin I signal intensities. In old rats, ghrelin and estrogen/ghrelin significantly decreased both intensities with greater estrogen/ghrelin effect. Ghrelin receptors were not immunostained in any muscle. Estrogen and/or ghrelin significantly increased or decreased, respectively, circulating growth hormone in old and young adult rats. Estrogen/ghrelin administration reversed pelvic floor muscle ageing changes in old ovariectomized rats through growth hormone production.     

The effect of ovariectomy on biomarkers of urogenital ageing in old versus young adult rats

The aim of this study was to compare the effects of ageing and ovariectomy on biomarkers of urogenital ageing in old and young-adult rats. Fisher 344 rats (18- and 3-months-old, n = 6 x 2) underwent ovariectomy. Age-matched sham animals received no intervention (n = 6 x 2). One month later, biomarkers of urogenital ageing were evaluated (light microscopic count of urethral and anal canal submucosal blood vessels, Western blot analysis of urethral, and anal canal submucosal collagen I and III and cytoplasmic p27(kip1) expression in the striated urethral and anal sphincters and levator ani and gel electrophoresis of isomyosin I proportion in these muscles) and compared in all groups (n = 24). All biomarkers of urogenital ageing studied were significantly increased in old compared to young-adult sham rats. Ovariectomy significantly increased these changes further in old versus young-adult rats with either smaller or larger differential effect than ageing compared to young-adult sham animals. Ovariectomy significantly exacerbates normative urogenital ageing changes in rats.     

Immunoreactivity of p27<Superscript>(Kip1)</Superscript>, cyclin D3, and Ki67 in conventional renal cell carcinoma

The goal of the study was to evaluate expression of the cell-cycle regulatory proteins (p27^(Kip1) and cyclin D3) and proliferation marker Ki67 in normal human kidneys and renal cell carcinoma (RCC) tissues. Intensity of the markers’ expression was prospectively studied and compared between normal and RCC tissue samples. Association was analyzed with cancer clinical parameters. p27^(Kip1) was significantly upregulated in normal compared with in RCC samples. Immunoreactivity of the protein negatively correlated with tumor size and was associated with pathological stage and grade. Patients with symptomatic disease had significantly less marker expression than those with incidentally discovered tumors. Intensity of Ki67 staining positively correlated with primary tumor size and associated with disease stage and grade. Cyclin D3 immunoreactivity positively correlated with tumor size. Loss of p27^(Kip1) expression, pathological stage, grade, and tumor size were risk factors for disease recurrence (P = 0.0072, 0.0011, and 0.0467, and P < 0.0001, respectively) and patient death (P = 0.0021, 0.0106, 0.0151, and 0.0021, respectively). With Cox multivariate analysis loss of p27^(Kip1) expression (hazard ratio 9.3, P = 0.002) and tumor size (hazard ratio 5.9, P = 0.015) were the predictors of cancer-specific survival. In conclusion, intensity of the markers’ expression in RCC is associated with tumour clinical parameters (size, stage, grade, and disease presentation type). Loss of p27^(Kip1) expression is a risk factor for the disease recurrence and cancer-related patient death.     

Adenovirus Expressing Mutant p27 kip1 Enhanced Apoptosis and Inhibited the Growth of Xenografted Human Breast Cancer

Purpose To evaluate the anti-tumor effects of a novel adenovirus expressing mutant p27 ^kip1 (Adp27-mt), which consists of a mutation of Thr-187/Pro-188 to Met-187/Ile-188. Methods Using the human breast cancer cell lines, MDA-MB-231, ZR-75-1, and MCF-7, we tested Adp27-mt for cell cycle assay, growth inhibition assay, and TdT-mediated dUTP-biotin nick end labeling in a human breast cancer-grafted severe combined immunodeficiency (SCID) mouse model. Results The mutant p27 ^kip1 induced stronger apoptosis in the breast cancer cell lines than adenovirus expressing wild-type p27 ^kip1 (Adp27-wt). Adp27-mt inhibits cell growth significantly; being about 5- and 3.5-fold stronger for IC50 than Adp27-wt in the breast cancer cell lines, MDA-MD-231 and ZR-75-1, respectively. In the human breast cancer-grafted SCID mouse model, Adp27-mt induced tumor regression and antitumor effects significantly better than Adp27-wt. Furthermore, Adp27-mt mainly caused G2/M arrest in the cell cycle progression, whereas Adp27-wt mediated a G1/S arrest 48 h after infection. Conclusion The mutant p27 ^kip1 protein induced apoptosis, and inhibited cell growth more efficiently with stronger anti-tumor effects than wild-type p27 ^kip1 . Thus, the recombinant adenovirus expressing mutant p27 ^kip1 could be useful in gene therapy against breast cancer.     

Loss of p27<Superscript>(Kip1) </Superscript>CDKI is a predictor of poor recurrence-free and cancer-specific survival in patients with renal cancer

The importance of cyclin-dependent kinase inhibitors (CDKI) in benign and malignant urological diseases is a subject of intense ongoing investigation. The goal of the current study was to analyze the expression of p27^(Kip1) CDKI in benign and malignant renal cells and assess their possible association with different clinical parameters. Expression of p27^(Kip1) was evaluated and compared in 24 normal human kidneys and in 52 renal cell carcinoma (RCC) tissue samples. Intensity of the expression was compared between the groups and association was analyzed with cancer clinical parameters. The expression of the marker was significantly higher in normal than in RCC samples (P = 0.0045). Intensity of p27^(Kip1) expression in RCC was negatively correlated with tumor size (Rho = −0.438, P = 0.0051) and associated with pathological stage and grade (P = 0.0488 and < 0.0001, respectively). The patients with symptomatic disease had significantly less marker expression than incidentally discovered tumors (P = 0.0301). Loss of p27^(Kip1) expression, pathological stage, grade and tumor size were the risk-factors for disease recurrence (P = 0.0072, 0.0011, 0.0467 and < 0.0001, respectively) and patient survival (P = 0.0021, 0.0106, 0.0151 and 0.0021, respectively). With Cox multivariate analysis loss of p27^(Kip1) expression (hazard ratio 9.3, P = 0.002) and tumor size (hazard ratio 5.9, P = 0.015) were the predictors of cancer-specific survival. Expression of p27^(Kip1) is significantly decreased in RCC as compared with normal kidney tissue. Intensity of the expression is associated with clinical parameters: tumor size, stage, grade and disease presentation. Loss of p27^(Kip1) expression is a risk-factor for disease recurrence and the strongest predictor of cancer-specific survival.     

Expression of p27<Superscript>(Kip1)</Superscript>, cyclin D3 and Ki67 in BPH,prostate cancer and hormone-treated prostate cancer cells

p27^(Kip1), cyclin D3 and Ki67 are the markers of DNA damage and cell proliferation. The goal of the current study was to analyze expression of the markers in benign and malignant prostate cancer tissues. Activity of p27^(Kip1), cyclin D3 and Ki67 was immunohistochemically evaluated in different cells of BPH, prostate cancer (PCa) and hormonally treated prostate cancer (HTPCa) tissues. The tissue samples were derived by means of TURP or radical prostatectomy. Intensity of the expression was compared between the groups, and association was sought with clinical parameters. Total expression of p27^(Kip1) was significantly higher in BPH as compared with PCa. Epithelial marker expression was higher in HTPCa than in PCa. Intensity of the expression in epithelial, vascular and ductal cells was negatively associated with the tumor stage and Gleason grades. Total Ki67 activity was positively correlated with patient age and serum PSA level. There was significantly higher expression in PCa and hormone-escaped PCa (HEPCa) as compared with BPH. Epithelial and vascular marker expression was positively associated with tumor stage and Gleason grades. There was a positive correlation between cyclin D3 and serum PSA level. With the increase of Gleason grades, cyclin D3 expression increased significantly. Expression of p27^(Kip1) negatively correlated with Ki67 and cyclin D3, while the latter two markers correlated positively. p27^(Kip1) is down-regulated, whereas Ki67 and cyclin D3 are up-regulated in PCa. Intensity of the markers’ expression is associated with tumor stage and grades. Hormonotherapy of PCa causes activation of p27^(Kip1). HEPCa is characterized by increased Ki67 expression.     

Combined estrogen and ghrelin administration restores number of blood vessels and collagen type I/III ratio in the urethral and anal canal submucosa of old ovariectomized rats

We compare the effects of estrogen and/or ghrelin on vascular counts and collagen I/III ratio of urethral and anal canal submucosa in old vs young-adult ovariectomized rats. Ovariectomized Fisher 344 rats (18 and 3 months old, n = 24 x 2) received 42 daily intraperitoneal 17-ss estradiol (10 microg/kg), ghrelin (2 microg/kg), both, or vehicle (n = 6 x 4 per group). Blood vessel counts and collagen I/III ratio were measured, respectively, by light microscopy and Western blot analysis with immunohistochemistry of ghrelin receptors. Estrogen significantly increased urethral and anal vascular counts and collagen I/III ratio in young-adult rats. In old rats, only combined estrogen/ghrelin administration significantly increased both variables. This was not observed with estrogen or ghrelin separately. Ghrelin receptors were immunostained in urethral and anal submucosa of all samples. Combined estrogen/ghrelin administration restored postovariectomy urethral and anal canal submucosal vessel number and collagen I/III ratio in old rats suggesting independent ageing effect.     

Effects of ovariectomy and hormone replacement on submucosal collagen and blood vessels of the anal canal of rats

OBJECTIVE: To study the effects of oestrogen and progesterone on submucosal collagen fibres and vascular plexus of the anal canal. MATERIALS AND METHODS: Experiments were performed on sections of the anal canal of ovariectomized rats following 28 daily subcutaneous injections of 17-beta oestradiol (n = 6, OVX + E, Group 1), medroxyprogesterone acetate (n = 6, OVX + P, Group 2), both drugs (n = 6, OVX + E + P, Group 3) or vehicle (n = 6, OVX) and after sham surgery without castration or injection (n = 6). Investigations included immunohistochemistry of oestrogen and progesterone receptors and collagen fibres, Western blot analysis of collagen types I and III and counting of perianal vessels by light microscopy. RESULTS: There was positive immunostaining for oestrogen and progesterone receptors in the mucosa and for collagen types I and III in the submucosa in all samples. Type I collagen levels increased significantly with ovariectomy but were normalized with treatment with oestrogen and progesterone. Type III collagen levels decreased after ovariectomy. Administration of oestrogen and progesterone appeared to restore level to near sham values. Semi-quantitative measurement of Type I/III collagen ratios by signal intensity demonstrated a very high ratio after ovariectomy. This appeared to be restored by both oestrogen and progesterone administration either individually or in combination. Mean vessel count was significantly lower in sham animals compared to values in OVX animals (P = 0.006). However, while only oestrogen treatment increased significantly the number of vessels compared to sham animals (P = 0.04), replacement with progesterone did not affect and in combination with oestrogen reduced submucosal vessel number. CONCLUSION: Oestrogen and progesterone have synergistic effects on collagen types I and III and probably antagonistic effects on the vascular plexus of the anal canal submucosa in adult female rats.     

Comparison of the main body of the external anal sphincter muscle cross-sectional area between women with and without prolapse

The aim of the study was to compare the main body of the external anal sphincter (EAS) cross-sectional area (CSA) of women with and without pelvic organ prolapse. Pelvic magnetic resonance imaging (MRI) scans of 40 women were selected for analysis. Of these women, 20 had pelvic organ prolapse and 20 had normal support. Of the women with normal support, 10 had known major levator ani (LA) muscle defects and 10 had normal LA muscles. The same was true for the women with pelvic prolapse: half had major LA defects and half had no LA defects. All patients had previously completed pelvic MRI in the supine position. 3-D models of the EAS were made and CSA of the EAS perpendicular to the fiber direction were measured circumferentially at 30° intervals. Univariable and multivariable analyses were performed. The mean CSA did not significantly differ between women with prolapse and normal support regardless of LA defect status (normal/−LA defect = 1.13 cm², prolapse/−LA defect = 0.86 cm², p = 0.065; normal/+LA defect = 1.08 cm², prolapse/+LA defect = 1.28 cm², p = 0.28). Women with prolapse and LA defects had a 49% larger mean muscle CSA compared to prolapse patients without LA defects (p = 0.01). This difference associated with defect status in prolapse patients was not seen in women with normal support. Women with prolapse alone had external anal sphincter CSAs that were comparable to women with normal support. However, women with both prolapse and a major levator ani defect had larger external anal sphincter CSAs compared to prolapse patients without levator ani defects.     

KB-R9032, newly developed Na<Superscript>+</Superscript>/H<Superscript>+</Superscript> exchange inhibitor,attenuates reperfusion-induced arrhythmias in isolated perfused rat heart

Purpose This study was conducted to elucidate the effects of KB-R9032, a newly developed Na⁺-H⁺ exchange inhibitor, on reperfusion-induced ventricular arrhythmia in the isolated perfused rat heart.Methods Male Wistar rat hearts (n = 48; 12 for each group) were perfused with modified Krebs-Ringers solution equilibrated with 5% carbon dioxide in oxygen by means of the Langendorff technique. An occluder was placed around the left anterior descending coronary artery (LAD). Heart rate, coronary flow, and ECG were monitored. Drug-free perfusate was used for 10min before switching to a perfusate containing various concentrations of KB-R9032. The added concentrations of KB-R9032 varied in the range of 0 (control) to 1 × 10^–5mol·l^–1. Each heart was subjected to regional ischemia (occlusion of LAD for 11min) and to 3min of reperfusion (release of the ligation).Results In the control group, reperfusion-induced ventricular fibrillation (VF) occurred in 91.7%, and the duration was 158.2 ± 14.4s (mean ± SEM); however, 1 × 10^–7, 1 × 10^–6, and 1 × 10^–5mol·l^–1 KB-R9032 reduced the incidence of VF to 75.0%, 42.9%, and 6.7%, respectively (P < 0.05 at 1 × 10^–5mol·l^–1 of KB-R9032) and reduced the duration of VF to 64.8 ± 22.1, 16.8 ± 10.1, and 1.2 ± 1.2s, respectively (P < 0.05 at 1 × 10^–6 and 1 × 10^–5mol·l^–1 of KB-R9032).Conclusion It was shown in this study that the Na⁺/H⁺ exchange inhibitor KB-R9032 suppresses reperfusion arrhythmias in the ischemia-reperfusion model of isolated rat heart.     

Combined [<Superscript>18</Superscript>F]Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) for Detection of Recurrent, <Superscript>131</Superscript>I-Negative Thyroid Cancer

Background Whole-body ¹³¹I scintigraphy (WBS) and serial thyroglobulin measurement (Tg) are standard methods for detecting thyroid cancer recurrence after total/near total thyroidectomy and ¹³¹I ablation. Some patients develop elevated Tg (Tg-positive) or there is clinical suspicion of recurrence, but WBS are negative (WBS-negative). This may reflect non-iodine-avid recurrence or metastasis. In 2002, the Centers for Medicare and Medicaid Services (CMS) approved positron emission tomography with [¹⁸F]fluorodeoxyglucose (FDG-PET) for Tg-positive/WBS-negative patients with follicular-cell-origin thyroid cancer. Limited data are available regarding the performance of combined FDG-PET/computed tomography (FDG-PET/CT) for detecting recurrent thyroid cancer in WBS-neg patients. Methods This retrospective review of prospectively collected data analyzed 65 patients who had FDG-PET/CT for suspected thyroid cancer recurrence (April 1998–August 2006). Patients were WBS-negative but were suspected to have recurrence based on Tg levels or clinical grounds. Suspected FDG-PET/CT abnormalities were reported as benign or malignant. Lesions were ultimately declared benign or malignant by surgical pathology or clinical outcome (disease progression). Results Of 65 patients who underwent FDG-PET/CT, 47 had positive FDG-PET/CT. Of the positive FDG-PET/CT, 43 studies were true positives, with 21 (49%) confirmed pathologically by surgical resection. The four false positives (3/4 confirmed pathologically) included an infundibular cyst, an inflamed supraclavicular cyst, pneumonitis, and degenerative disc disease. Of the 18 FDG-PET/CT studies that were negative, 17 were true negatives and one was a false negative (metastatic papillary carcinoma). Thus, FDG-PET/CT demonstrated a patient-based sensitivity of 98%, specificity of 81%, positive predictive value of 91%, and negative predictive value of 94%. Conclusions FDG-PET/CT is useful for detecting thyroid cancer recurrence in WBS-negative patients, and can assist decision making.     

Cellular and molecular mechanisms regulating vascular tone. Part 2: regulatory mechanisms modulating Ca<Superscript>2+</Superscript> mobilization and/or myofilament Ca<Superscript>2+</Superscript> sensitivity in vascular smooth muscle cells

Understanding the physiological mechanisms regulating vascular tone would lead to better circulatory management during general anesthesia. This two-part review provides an overview of current knowledge about the cellular and molecular mechanisms regulating the contractile state of vascular smooth muscle cells (i.e., vascular tone). The first part reviews basic mechanisms controlling the cytosolic Ca²⁺ concentration in vascular smooth muscle cells, and the Ca²⁺-dependent regulation of vascular tone. This second part reviews the regulatory mechanisms modulating Ca²⁺ mobilization and/or myofilament Ca²⁺ sensitivity in vascular smooth muscle cells—including Rho/Rho kinase, protein kinase C, arachidonic acid, Ca²⁺/calmodulin-dependent protein kinase II, caldesmon, calponin, mitogen-activated protein kinases, tyrosine kinases, cyclic nucleotides, Cl⁻ channels, and K⁺ channels.     

HPV DNA is Associated with a Subset of Schneiderian Papillomas but Does not Correlate with p16<Superscript>INK4a</Superscript> Immunoreactivity

This study investigated the role of human papillomavirus (HPV) in Schneiderian papillomas (SPs) to determine whether HPV is associated with the pathogenesis of particular histologic subtypes and whether p16^INK4a can be used as a surrogate marker for HPV detection. Twenty-seven papilloma specimens (19 inverted [IPs], 6 exophytic [EPs], 1 oncocytic [OP] and 1 mixed) were collected from 23 patients. Purified SP DNA extracts were tested for HPV by PCR using GP5 +/GP6 + primers; HPV genotyping was performed by dot blot hybridization. PCR positive specimens were screened for HPV by biotinyl-tyramide-based chromogenic in situ hybridization (CISH). Immunohistochemsistry (IHC) for the HPV L1 capsid protein and for p16^INK4a was performed on all specimens. HPV was detected by PCR in 16/27 (59.3%) SPs; 9/19 (47.4%) IPs; 6/6 (100%) EPs [p = 0.051], and 1/1 (100%) mixed SP. HPV was not detected in the single OP. High risk genotypes were detected in 4/9 IPs (44.4%) and 0/6 EPs (0%) [p = 0.10]. Seven of 16 PCR positive SPs were also CISH positive for HPV: 5/6 EPs (83.3%) and 1/9 IP (11.1%) [p = 0.01]. IHC for the L1 capsid protein was positive in 2 SPs (1 EP and 1 mixed). p16^INK4a staining was seen in 14/16 (87.5%) PCR positive SPs and in 10/11 (90.9%) PCR negative SPs (p = 1.00). In summary, this study demonstrates a strong association between HPV and EPs, however, its role in IPs remains less well-defined. Further, p16^INK4a is not a useful surrogate marker for HPV detection across the various SPs.     

The value of EZH2, p27kip1, BMI‐1 and MIB‐1 on biopsy specimens with low‐risk prostate cancer in selecting men with significant prostate cancer at prostatectomy

OBJECTIVE

To assess the additional prognostic value of the molecular markers EZH2, MIB‐1, p27^kip1 and BMI‐1 on needle biopsies from men with low‐risk prostate cancer, as this disease in needle biopsies shows a heterogeneous clinical outcome, and while it is known that the expression of these tissue markers is predictive of the clinical outcome after radical prostatectomy (RP) their value in prostate biopsies is largely unknown.

PATIENTS AND METHODS

The study included men participating in a screening study, diagnosed with low‐risk prostate cancer and subsequently treated with RP. Immunohistochemical staining for EZH2, MIB‐1, p27^kip1 and BMI‐1 on the needle biopsies were (semi)quantitatively scored and expression levels were related to significant disease at RP. Clinical low‐risk prostate cancer was defined as a prostate‐specific antigen (PSA) level of ≤10 ng/mL, clinical T‐stage ≤2, biopsy Gleason score ≤6, a PSA density of <0.20 ng/mL/g and two or fewer positive cores. Significant PC at RP was defined as presence of any of extracapsular extension, Gleason pattern 4/5, or tumour volume ≥0.5 mL.

RESULTS

In all, 86 biopsy specimens were included; there was high EZH2 expression (>1.0%) in 42% and a low p27^kip expression (<90%) in 63%. Significant disease was present in 44 (51%) RP specimens. A high EZH2 (odds ratio 3.19, P = 0.043) and a low p27^kip1 (4.69, P = 0.036) were independent predictors for significant prostate cancer at RP.

CONCLUSIONS

The determination of EZH2 and p27^kip1 on diagnostic needle biopsies supports the selection of men with indolent prostate cancer at RP. Especially p27^kip1 could improve the pretreatment risk assessment of patients with low‐risk prostate cancer.     

MRI and <Superscript>18</Superscript>FDG-PET in the assessment of bone marrow infiltration of the spine in cancer patients

The aim of this study was to evaluate the diagnostic value of MRI and ¹⁸FDG-PET in bone marrow infiltration of the spine due to metastases of solid tumours and lymphoma in cancer patients. In 35 cancer patients (solid tumours n = 26, lymphoma n = 9) MRI of the spine and ¹⁸FDG-PET were reviewed and the detectability of metastases, infiltration of the spine, extent of disease, and therapeutic implications were compared. In 8/35 cases (23%) imaging technique showed concordantly no bone marrow infiltration. In 19/35 patients (54%), both MRI and ¹⁸FDG-PET revealed bone marrow infiltration of the axial skeleton. In 12/19 patients (63%), MRI showed more extensive disease which lead to subsequent therapy. The imaging findings of MRI and ¹⁸FDG-PET were discordant in 8/35 cases (23%). ¹⁸FDG-PET was false positive in two patients. In six patients, ¹⁸FDG-PET failed to detect bone metastases and bone marrow infiltration of the spine, which was detected by MRI and proven by clinical follow-up with subsequent therapy in two cases. MRI is more sensitive and specific than ¹⁸FDG-PET detecting bone marrow metastases and infiltration of the spine and has a great impact in staging cancer patients.     

Comparison of Uptake Characteristics and Prognostic Value of <Superscript>201</Superscript>Tl and <Superscript>18</Superscript>F-FDG in Esophageal Cancer

Background Patients with esophageal cancer often undergo ²⁰¹Tl myocardial imaging for preoperative risk evaluation, thereby providing an excellent opportunity to assess tumor handling of ²⁰¹Tl. We thus compared the characteristics of ²⁰¹Tl and ¹⁸F-FDG uptake by esophageal cancer and further investigated their prognostic values. Methods The study included 100 newly diagnosed esophageal cancer patients who underwent preoperative ²⁰¹Tl SPECT and ¹⁸F-FDG PET exams. Tumor to mediastinal uptake (T/M) ratio and retention index (RI) of ²⁰¹Tl, tumor ¹⁸F-FDG pSUV, tumor size, location, and stage were assessed. Survival analysis was performed for disease-free survival using the Kaplan–Meier method. Cox proportional hazard models were used to determine independent risk factors. Results ²⁰¹Tl SPECT and ¹⁸F-FDG PET visualized the primary tumor in 85/100 (85.0%) and 91/100 (91.0%) patients, respectively (p = 0.03). There were close correlations between early and delayed ²⁰¹Tl T/M ratios (r = 0.83, p < 0.0001) and between T/M ratios and ¹⁸F-FDG pSUV (r = 0.56 and 0.57, respectively, both p < 0.0001). Both T/M ratios and ¹⁸F-FDG pSUV correlated significantly with tumor stage (ρ = 0.45, 0.40, and 0.59, respectively, all p < 0.0001). Survival analysis revealed tumor size, ²⁰¹Tl negative tumors, ¹⁸F-FDG negative tumors, delayed ²⁰¹Tl T/M ratio, RI, stage, and ¹⁸F-FDG pSUV to be significant univariate predictors for disease-free survival. Multivariate survival analysis showed stage (p = 0.02) to be a significant independent prognostic predictor. Conclusions In patients with esophageal cancer, assessment of tumor ²⁰¹Tl uptake, as with ¹⁸F-FDG, may provide potentially useful information regarding tumor characteristics. Presented in part at the 51st Annual Meeting of the Society of Nuclear Medicine, Philadelphia, PA, USA, June 19–23, 2004.     

Calcium Absorption and Bone Loss in Ovariectomized Rats Fed Varying Levels of Dietary Calcium

The following studies were undertaken to examine whether estrogen deficiency impairs calcium absorption in aged rats, and to determine whether impaired calcium absorption and the level of dietary calcium are related to the degree of bone loss due to estrogen deficiency. Sixty rats were sham operated (Sham) or ovariectomized (Ovx) to make them estrogen deficient and divided into three dietary groups of 10 rats per group: Group 1 (Sham) and Group 2 (Ovx) were maintained on a diet containing 0.5% calcium; Group 3 (Sham) and Group 4 (Ovx) were maintained on a diet containing 0.1% calcium; Group 5 (Sham) and Group 6 (Ovx) were maintained on a diet containing 0.02% calcium. Calcium absorption was measured in all animals at the beginning of the study and 2 weeks, 1 month, 2 months, and 3 months following surgery, then the animals were sacrificed. In Ovx rats fed 0.5% Ca diet, calcium absorption decreased progressively and the decrease became statistically significant 8 and 12 weeks following ovariectomy (P < 0.05). A similar ovariectomy-related impairment of calcium absorption was not observed in animals fed diets with lower calcium content, making the Ovx rat a tenuous model of intestinal calcium malabsorption. Low dietary calcium decreased cancellous bone mineral content and density at the proximal tibial metaphysis and the decrease was augmented by ovariectomy. The degree of osteopenia due to ovariectomy was not related to the level of dietary calcium or the efficiency of calcium absorption. Received: 7 July 1998 / Accepted: 23 December 1998     

Cellular and molecular mechanisms regulating vascular tone. Part 1: basic mechanisms controlling cytosolic Ca<Superscript>2+</Superscript> concentration and the Ca<Superscript>2+</Superscript>-dependent regulation of vascular tone

General anesthetics cause hemodynamic instability and alter blood flow to various organs. There is mounting evidence that most general anesthetics, at clinical concentrations, influence a wide variety of cellular and molecular mechanisms regulating the contractile state of vascular smooth muscle cells (i.e., vascular tone). In addition, in current anesthetic practice, various types of vasoactive agents are often used to control vascular reactivity and to sustain tissue blood flow in high-risk surgical patients with impaired vital organ function and/or hemodynamic instability. Understanding the physiological mechanisms involved in the regulation of vascular tone thus would be beneficial for anesthesiologists. This review, in two parts, provides an overview of current knowledge about the cellular and molecular mechanisms regulating vascular tone—i.e., targets for general anesthetics, as well as for vasoactive drugs that are used in intraoperative circulatory management. This first part of the two-part review focuses on basic mechanisms regulating cytosolic Ca²⁺ concentration and the Ca²⁺-dependent regulation of vascular tone.