Characterization of [3H]brevetoxin binding to voltage-dependent sodium channels in adrenal medullary cells

We have previously reported that in bovine adrenal chromaffin cells Ptychodiscus brevis toxin-3 (PbTx-3) does not alter the veratridine-induced ²²Na influx when given alone, but increases the influx of ²²Na when co-applied with either - or -scorpion venom (Wada et al. 1992). In the present study, we characterized [³H]PbTx-3 binding in bovine adrenal chromaffin cells. [³H]PbTx-3 binding was saturable, reversible and of high-affinity with an equilibrium dissociation constant (K_d) of 32.0±4.9 nmol/1 and a maximum binding capacity B_max of 6.2 ± 1.2 pmol/4 × 10⁶ cells (4.5 ± 0.9 pmol/mg cell protein). A Hill plot revealed the lack of cooperative interaction among the binding sites. Unlabelled PbTx-3 inhibited [³H]PbTx-3 binding with an IC₅₀ of 31 nmol/l. However, tetrodotoxin, veratridine, - and -scorpion venom, or veratridine in combination with either - or -scorpion venom did not alter [³H]PbTx-3 binding. All these results suggest that PbTx-3 binds to a site (site 5) distinct from the previously known four toxin binding sites, which does not gate voltage-dependent Na channels by itself, but is specifically involved in the allosteric modulation of Na channels in adrenal medullary cells. Correspondence to: A. Wada at the above address     

Regulation of herbivore growth by the balance of light and nutrients

Experiments using planktonic organisms revealed that the balance of radiant energy and available nutrients regulated herbivore growth rates through their effects on abundance and chemical composition of primary producers. Both algae and herbivores were energy limited at low light/nutrient ratios, but both were nutrient limited at high light/nutrient ratios. Herbivore growth increased with increasing light intensity at low values of the light/nutrient ratio due to increases in algal biomass, but growth decreased with increasing light at a high light/nutrient ratio due to decreases in algal quality. Herbivore production therefore was maximal at intermediate levels of the light/nutrient ratio. The results contribute to an understanding of mass transfer mechanisms in ecosystems and illustrate the importance of integration of energy-based and material-based currencies in ecology.     

Gene transfer into rat renal cells using adeno-associated virus vectors

Adeno-associated virus (AAV) vectors have a number of attractive features, including lack of cytotoxicity, ability to transduce nondividing cells, and long-term transgene expression. We investigated whether rat renal cells could be efficiently transduced with AAV vectors. Rat glomerular mesangial cells were transduced with AAV-lacZ vector containing beta-galactosidase gene in vitro, and the expression of beta-galactosidase was evaluated by X-gal staining and ELISA. For ex vivo experiments, sections of rat kidneys were incubated with AAV-lacZ, and then evaluated by X-gal histochemical staining. The level of beta-galactosidase expression in cultured rat mesangial cells increased in a dose-dependent manner (ranging from 1 x 10(5) to 5 x 10(6) particles/cell). When transduced with 5 x 10(6) vector particles/cell of AAV-lacZ, about 50% of mesangial cells were stained positively with X-gal, and the level of beta-galactosidase expression reached 9.9 +/- 1.5 ng/mg protein. Expression was detectable during the culture period for at least 7 days. X-gal histochemical examination of the ex vivo transduced renal tissue revealed tubular cell and interstitial tissue staining. However, gene transfer was not clearly observed in glomeruli. These findings suggest that AAV vectors have the potential for gene therapy of renal diseases.     

Highly sensitive detection of melanoma at an early stage based on the increased serum secreted protein acidic and rich in cysteine and glypican-3 levels.

PURPOSE: There are no available tumor markers detecting primary melanoma at an early stage. The identification of such serum markers would be of significant benefit for an early diagnosis of melanoma. We recently identified glypican-3 (GPC3) as a novel tumor marker but could diagnose only 40% of melanomas. Thereby, we focused out attention on secreted protein acidic and rich in cysteine (SPARC) overexpressed in melanoma as another candidate for tumor marker. EXPERIMENTAL DESIGN: Secreted SPARC protein was quantified using ELISA in the sera from 109 melanoma patients, five patients with large congenital melanocytic nevus, 61 age-matched healthy donors, and 13 disease-free patients after undergoing a surgical removal. We also quantified GPC3 and 5-S-cysteinyldopa in the same serum samples and compared these markers for their diagnostic value. RESULTS: The serum SPARC concentrations in melanoma patients were greater than those in healthy donors (P = 0.001). When we fixed a cutoff value at the mean concentration plus 2 SD of the healthy donors, the serum SPARC was found to have increased in the sera of 36 of the 109 (33%) melanoma patients, whereas there were three (4.9%) false-positive cases of 61 healthy donors. Surprisingly, 19 of 36 patients showing increased SPARC levels were in stages 0 to II. The serum SPARC level decreased under the cutoff level in 10 of 13 patients after surgical removal. Using SPARC and GPC3 in combination thus enabled us to diagnose 47 of 75 (66.2%) melanoma patients at an early stage (0-II). CONCLUSIONS: SPARC or its combination with GPC3 is thus considered a potentially useful tumor marker, especially for melanoma at an early stage.     

Gender-specific Differences in Clinicopathologic Outcomes Following Radical Cystectomy: An International Multi-institutional Study of More Than 8000 Patients

Background

The impact of gender on the staging and prognosis of urothelial carcinoma of the bladder (UCB) is insufficiently understood.

Objective

To assess gender-specific differences in pathologic factors and survival of UCB patients treated with radical cystectomy (RC).

Design, setting, and participants

Data from 8102 patients treated with RC (6497 men [80%] and 1605 women [20%]) for UCB between 1971 and 2012 were analyzed.

Outcome measurements and statistical analysis

Multivariable competing-risk regression analyses were performed to evaluate the relationship of gender on disease recurrence (DR) and cancer-specific mortality (CSM). We also tested the interaction of gender and tumor stage, nodal status, and lymphovascular invasion (LVI).

Results and limitations

Female patients were older at the time of RC (p = 0.033) and had higher rates of pathologic stage T3/T4 disease (p < 0.001). In univariable, but not in multivariable analysis, female gender was associated with a higher risk of DR (p = 0.022 and p = 0.11, respectively). Female gender was an independent predictor for CSM (p = 0.004). We did not find a significant interaction between gender and stage, nodal metastasis, or LVI (all p values >0.05).

Conclusions

We found female gender to be associated with a higher risk of CSM following RC. However, these findings do not appear to be explained by gender differences in pathologic stage, nodal status, or LVI. This gender disparity may be due to differences in care and/or the biology of UCB.     

Impact of Triggering Events on Outcomes of Acute Heart Failure

Background

The onset of acute heart failure is known to be associated with increased physical activity and other specific behaviors that can trigger hemodynamic deterioration. This analysis aimed to describe the distribution of triggers in patients hospitalized for acute heart failure, and investigate their effects on in-hospital outcomes.

Age-related differences in the delivery of cardiac management to women versus men with acute myocardial infarction in Japan: Tokai Acute Myocardial Infarction Study: TAMIS

It is of concern that women are more likely to undergo fewer diagnostic tests and receive less treatment for acute myocardial infarction (AMI) than men. However, it is still unclear whether gender differences exist according to age groups. Therefore, we studied the influence of gender on the delivery of cardiac management according to two age groups (< 65, >or= 65) in Japan. Data from the Tokai Acute Myocardial Infarction Study (TAMIS) sample were used. This is a retrospective study of all consecutive patients admitted to the 13 acute care hospitals in the Tokai region of Japan, which includes Aichi and Shizuoka Prefectures, with a diagnosis of AMI from 1995 to 1997. A total of 143 younger women, 822 younger men, 391 older women, and 611 older men were included. Information concerning patient demographics, in-hospital course, comorbid conditions, electrocardiography (ECG), ultrasound-echocardiography (UCG), treadmill test (TMT), coronary angiography (CAG), percutaneous transluminal coronary angioplasty (PTCA), coronary artery bypass graft (CABG), intra-aortic balloon pump (IABP), mechanical ventilation, and in-hospital or discharge medication (thrombolytics, vasopressors, aspirin, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, calcium antagonists, nitrates) were collected. Among the young, after controlling for these baseline variables, women were significantly less likely to undergo PTCA compared to men (OR, 0.54, 95%CI, 0.35-0.82). After controlling for these baseline variables, only lipid-lowering therapy tended to be more frequent in women than in men among the elderly (OR, 2.79, 95%CI, 1.47-2.58). The findings suggest that younger women with AMI are less likely than younger men to undergo PTCA, and that older women with AMI are more likely to receive lipid-lowering therapy.     

Establishment of a leukaemic cell line from a patient with acquisition of chromosomal abnormalities during disease progression in myelodysplastic syndrome

Summary. A cell line designated SKM-1 was newly established from leukaemic cells of a 76-year-old Japanese male patient with monoblastic leukaemia following myelodysplastic syndrome (MDS). The cells were obtained from peripheral blood of the patient when he lost multiple point mutations of ras genes with acquisition of chromosomal abnormalities during disease progression in MDS. The cells grew as a single floating cell, and have been continuously growing with the morphological characteristics of immature monoblasts by serial passages during the past 42 months with a doubling time of about 48 h. By cytochemical analysis. the cloned cells were positive for butyrate esterase, but negative for the Epstein-Barr virus associated nuclear antigen. Phenotypic analysis revealed the expression of myelomonocyte specific antigens such as CD4, CD13, CD33 and HLA-DR. Cells from the primary peripheral blood and those from SO passages of the SKM-1 cell line both possessed no activated ras genes but showed karyotype abnormalities with 46.XY, del(9)(q13;q22), der(17) t(17:?)(p13:?). The SKM-1 cells have two mutations in p53 gene and overexpress the pS3 products. This cell line may contribute to a better understanding of molecular mechanisms in the progression from MDS to myelogenous leukaemia.