Differentiation of proton-pumping activity in cultured renal inner medullary collecting duct cells

Cultured inner medullary collecting duct (IMCD) cells have been shown to secrete protons (H⁺) by two mechanisms: anN-ethylmaleimide-and dicyclohexyl-carbodiimide-sensitive electrogenic H⁺-ATPase or H⁺ pump, and an amiloride-sensitive, secondary active Na⁺/H⁺ exchanger. These cells also express Cl^–/HCO₃ ^– exchange and carbonic anhydrase activity in common with other renal epithelial cells involved in acid-base transport. Video fluorescence microscopy of individual cells using 2, 7-biscarboxyethyl-5(6)-carboxyfluorescein has demonstrated that adjacent-cultured IMCD cells show substantial functional intercellular heterogeneity. The development of H⁺-pumping activity is associated with high-baseline intracellular pH and peanut agglutinin (PNA) affinity, and loss of mitotic activity and of Na⁺/H⁺ exchange. The H⁺-pumping activity may be further enhanced by removal of fetal calf serum for 6–54 h or by selecting cells with high PNA affinity. IMCD cells in their most differentiated state form domes, which consistently showed the highest rates of H⁺-pumping activity, as well as high affinity for peanut lectin. When IMCD were plated at low density, domes developed relatively late (2–4 weeks), at which time cells located in the center of nests of contiguously growing cells were quiescent and showed H⁺-pumping activity but no Na⁺/H⁺ exchange. On the other hand, dense plating was associated with early development of domes (end of 1st week), at which time adjacent cells showed a high mitotic activity and Na⁺/H⁺ exchange, but no H⁺-pumping activity. We speculate that differentiation of IMCD cells results in the development of cell polarity. This could include either loss of the apical Na⁺/H⁺-exchange activity, or localization of this exchanger only to the basolateral membrane, while the H⁺ pump differentiates at the apical membrane.     

Influence of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the antigen-presenting activity of dendritic cells.

We have previously shown that exposure of mice to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) induces activation-like changes in splenic dendritic cells (DC) in the absence of antigen challenge. Since activation of DC reduces their ability to phagocytize antigen, we examined the effects of TCDD on the ability of DC to process and present antigen to antigen-specific T cells and to internalize latex beads. Additionally, the expression of costimulatory and adhesion molecules was examined on DC from TCDD-treated mice injected with allogeneic tumor cells. The ability of DC from C57Bl/6 mice to induce proliferation of keyhole limpet hemocyanin (KLH)-specific 10.5.17 T cells and production of IL-4 was not significantly altered by TCDD exposure, either when KLH was added in vitro or when the mice were injected with KLH prior to DC isolation. In contrast, ovalbumin (OVA) presentation by DC from TCDD-treated Balb/c mice induced enhanced proliferation of OVA-specific D011.10 T cells, although the production of IL-2 and IFN-gamma was not affected. Enhanced in vivo proliferation of adoptively transferred, CFSE-labeled DO11.10 T cells was also observed in TCDD-treated Balb/c mice that were challenged with OVA. TCDD treatment modulated the expression of major histocompatibility complex (MHC) class II, CD24, ICAM-1, CD40, and LFA-1 on splenic DC from C57Bl/6 mice injected with allogeneic tumor cells; however, the effects of TCDD were identical to changes seen previously in nonimmune mice, suggesting that these effects were not antigen-dependent. Finally, TCDD treatment did not affect the ability of splenic DC to internalize latex beads administered in vivo. Taken together, these results suggest that the activation-like changes induced in DC by TCDD do not suppress the ability of DC to process and present antigen, but may enhance their ability to provide activation signals to T cells. This, in turn, may alter the survival of the T cells, the DC, or both, and might lead to dysregulation of the immune response.     

Altered behavioral response to dopamine D3 receptor agonists 7-OH-DPAT and PD 128907 following repetitive amphetamine administration.

Behavioral sensitization, the progressive and enduring enhancement of certain behaviors following repetitive drug use, is mediated in part by dopaminergic pathways. Increased locomotor response to drug treatment, a sensitizable behavior, is modulated by an opposing balance of dopamine receptor subtypes, with D1/D2 dopamine receptor stimulation increasing and D3 dopamine receptor activation inhibiting amphetamine-induced locomotion. We hypothesize that tolerance of D3 receptor locomotor inhibition contributes to behavioral sensitization. In order to test the hypothesis that expression of behavioral sensitization results in part from release of D3 receptor-mediated inhibition, thereby resulting in decreased response to D3 receptor agonists, we examined the effect of repetitive amphetamine administration on the behavioral response to the D3 receptor preferring agonists 7-OH-DPAT and PD 128907. D3-selective effects have recently been described for both drugs at a low dose. At 1 week following completion of a repetitive treatment regimen, amphetamine-pretreated rats displayed a decreased response to D3-selective doses of both 7-OH-DPAT and PD 128907, when compared to animals receiving saline pretreatment. Moreover, in addition to the quantitative alteration in response, there was a change in the inter-relation between response to amphetamine and D3 agonist. A highly significant inverse relation between locomotor inhibitory response to PD 128907 and the locomotor-stimulant response to amphetamine was observed prior to amphetamine treatment. In contrast, 10 days following repetitive amphetamine treatment, the relation between response to PD 128907 and amphetamine was not detected. The observed behavioral alteration could not be accounted for by changes in D3 receptor binding in ventral striatum. These findings suggest a persistent release of D3 receptor-mediated inhibitory influence contributes to the expression of behavioral sensitization to amphetamine.     

Nonsteroidal anti-inflammatory drug use associated with reduced incidence of adenocarcinomas of the esophagus and gastric cardia that overexpress cyclin D1: a population-based study.

This study was undertaken to determine whether selected risk factors for esophageal and gastric cancer are associated with tumors that overexpress cyclin D1. Archived tumor tissue was available for 630 esophageal and gastric cancer patients who participated in a population-based case-control study. Patients were categorized into case groups based on whether protein overexpression of the cyclin D1 gene, as assessed by immunohistochemistry, was present (cyclin D1+, n = 285) or not (cyclin D1-, n = 345) in the tumor. The distribution of risk factors in each of these case groups was then compared with the distribution among the 695 controls. Multivariate-adjusted odds ratios (OR) for esophageal adenocarcinoma were reduced in relation to use of aspirin and other nonsteroidal anti-inflammatory drug (NSAID) use but only among patients with cyclin D1+ tumors (0.45, 95% confidence interval [CI] = 0.26, 0.79) and not among those with cyclin D1- tumors (1.12, 95% CI = 0.67, 1.86). A similar pattern was observed for gastric cardia adenocarcinomas. In contrast, ORs for esophageal squamous cell carcinoma and noncardia gastric adenocarcinomas in relation to NSAID use were reduced, regardless of cyclin D1 status. ORs did not vary with cyclin D1 status in relation to alcohol, body size, or cigarette smoking, with the following exception; for noncardia gastric adenocarcinomas the cyclin D1- tumors showed a 2-fold elevation in the OR with ever smoking. These data suggest that the reduction in risk associated with NSAID use may be restricted to those esophageal and gastric cardia adenocarcinomas that overexpress cyclin D1.     

Fruits, vegetables, and micronutrients in relation to breast cancer modified by menopause and hormone receptor status.

Whether fruit, vegetable, and antioxidant micronutrient consumption is associated with a reduction in breast cancer incidence remains unresolved. To address this issue, we analyzed data from a large population-based case-control study, with consideration given to whether the associations varied with menopausal status or with clinical characteristics of the cases' disease. Study participants completed a modified Block food frequency questionnaire, which included assessment of the frequency and portion sizes of 13 fruits and fruit juices and 16 vegetables and the use of multiple and single vitamin supplements. Statistical analyses were done on 1,463 cases and 1,500 controls. Among postmenopausal women, reduced odds ratios [OR; 95% confidence intervals (95% CI)] were noted for the highest fifth, as compared with the lowest fifth, of intake of any vegetables [0.63 (0.46-0.86); P for trend < 0.01] and leafy vegetables [0.66 (0.50-0.86); P for trend = 0.03] after controlling for age and energy intake. Adjusted ORs (95% CIs) were also decreased for postmenopausal breast cancer in relation to high intake of carotenoids, alpha-carotene, beta-carotene, lutein, and particularly lycopene [0.66 (0.48-0.90); P for trend = 0.03]. Inverse associations for fruits and vegetables were stronger for postmenopausal women with estrogen receptor (ER)+ tumors (OR, 0.65; 95% CI, 0.51-0.82) than ER- tumors (OR, 0.92; 95% CI, 0.64-1.32), but results were less consistent for micronutrients. No similarly reduced associations were observed among premenopausal women. ORs did not appreciably differ by in situ or invasive breast cancer or by whether cases had begun chemotherapy. Our results support an inverse association for fruit and vegetable intake among postmenopausal but not premenopausal breast cancer, which may be more pronounced among women with ER+ tumors.     

Antineoplastic effects of partially HLA-matched irradiated blood mononuclear cells in patients with renal cell carcinoma.

PURPOSE: Vaccines, cytokines, and other biologic-based therapies are being developed as antineoplastic agents. Many of these agents are designed to induce an autologous immune response directed against the malignancy. In contrast, hematopoietic stem-cell transplantation is being developed as a form of allogeneic immunotherapy. This study tests the tolerance and antineoplastic activity of sequential infusions of partially HLA-matched allogeneic blood mononuclear cells (obtained from relatives) when administered outside of the context of a hematopoietic stem-cell transplantation. The cells are irradiated to prevent graft-versus-host disease. PATIENTS AND METHODS: Fifteen patients with relapsed or refractory malignancies for which no standard therapy was available were enrolled onto a clinical trial designed to assess the tolerability and antineoplastic effects of irradiated partially HLA-matched blood mononuclear cells obtained from relatives. RESULTS: There was disease regression in three patients with metastatic renal cell carcinoma during treatment. There was disease progression in six patients with metastatic renal cell carcinoma and two patients with metastatic melanoma during treatment. There was no change in disease state in several other patients. CONCLUSION: Irradiated allogeneic blood mononuclear cells administered outside the context of hematopoietic stem-cell transplantation may induce disease responses in patients with relapsed or refractory malignancies. Transfusion of irradiated allogeneic blood mononuclear cells should be developed further as a novel therapeutic antineoplastic approach.     

Airborne dispersal as a novel transmission route of coagulase-negative staphylococci: interaction between coagulase-negative staphylococci and rhinovirus infection.

OBJECTIVE: To investigate whether rhinovirus infection leads to increased airborne dispersal of coagulase-negative staphylococci (CoNS). DESIGN: Prospective nonrandomized intervention trial. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Twelve nasal Staphylococcus aureus-CoNS carriers among 685 students screened for S. aureus nasal carriage. INTERVENTIONS: Participants were studied for airborne dispersal of CoNS in a chamber under three conditions (street clothes, sterile gown with a mask, and sterile gown without a mask). After 2 days of pre-exposure measurements, volunteers were inoculated with a rhinovirus and observed for 14 days. Daily quantitative nasal and skin cultures for CoNS and nasal cultures for rhinovirus were performed. In addition, assessment of cold symptoms was performed daily, mucous samples were collected, and serum titers before and after rhinovirus inoculation were obtained. Sneezing, coughing, and talking events were recorded during chamber sessions. RESULTS: All participants had at least one nasal wash positive for rhinovirus and 10 developed a symptomatic cold. Postexposure, there was a twofold increase in airborne CoNS (P = .0004), peaking at day 12. CoNS dispersal was reduced by wearing a gown (57% reduction, P < .0001), but not a mask (P = .7). Nasal and skin CoNS colonization increased after rhinovirus infection (P < .05). CONCLUSIONS: We believe this is the first demonstration that a viral pathogen in the upper airways can increase airborne dispersal of CoNS in nasal S. aureus carriers. Gowns, gloves, and caps had a protective effect, whereas wearing a mask did not further reduce airborne spread.     

Epidermal growth factor receptor mutations and gene amplification in non-small-cell lung cancer: molecular analysis of the IDEAL/INTACT gefitinib trials.

PURPOSE: Most cases of non-small-cell lung cancer (NSCLC) with dramatic responses to gefitinib have specific activating mutations in the epidermal growth factor receptor (EGFR), but the predictive value of these mutations has not been defined in large clinical trials. The goal of this study was to determine the contribution of molecular alterations in EGFR to response and survival within the phase II (IDEAL) and phase III (INTACT) trials of gefitinib. PATIENTS AND METHODS: We analyzed the frequency of EGFR mutations in lung cancer specimens from both the IDEAL and INTACT trials and compared it with EGFR gene amplification, another genetic abnormality in NSCLC. RESULTS: EGFR mutations correlated with previously identified clinical features of gefitinib response, including adenocarcinoma histology, absence of smoking history, female sex, and Asian ethnicity. No such association was seen in patients whose tumors had EGFR amplification, suggesting that these molecular markers identify different biologic subsets of NSCLC. In the IDEAL trials, responses to gefitinib were seen in six of 13 tumors (46%) with an EGFR mutation, two of seven tumors (29%) with amplification, and five of 56 tumors (9%) with neither mutation nor amplification (P = .001 for either EGFR mutation or amplification v neither abnormality). Analysis of the INTACT trials did not show a statistically significant difference in response to gefitinib plus chemotherapy according to EGFR genotype. CONCLUSION: EGFR mutations and, to a lesser extent, amplification appear to identify distinct subsets of NSCLC with an increased response to gefitinib. The combination of gefitinib with chemotherapy does not improve survival in patients with these molecular markers.     

Safety and tolerability of lamotrigine for bipolar disorder.

Tolerability and safety are important considerations in optimising pharmacotherapy for bipolar disorder. This paper reviews the tolerability and safety of lamotrigine, an anticonvulsant recommended in the 2002 American Psychiatric Association guidelines as a first-line treatment for acute depression in bipolar disorder and one of several options for maintenance therapy. This paper reviews the tolerability and safety of lamotrigine using data available from a large programme of eight placebo-controlled clinical trials of lamotrigine enrolling a total of nearly 1800 patients with bipolar disorder. This review is the first to collate all the safety information from these clinical trials, including data from four unpublished studies. The results these trials in which 827 patients with bipolar disorder were given lamotrigine as monotherapy or adjunctive therapy for up to 18 months for a total of 280 patient-years of exposure demonstrated that lamotrigine is well-tolerated with an adverse-event profile generally comparable with that of placebo. The most common adverse event with lamotrigine was headache. Lamotrigine did not appear to destabilise mood and was not associated with sexual adverse effects, weight gain, or withdrawal symptoms. Few patients experienced serious adverse events with lamotrigine, and the incidence of withdrawals because of adverse events was low. Serious rash occurred rarely (0.1% incidence) in the clinical development programme including both controlled and uncontrolled clinical trials. These findings - considered in the context of data showing lamotrigine to be effective for bipolar depression - establish lamotrigine as a well-tolerated addition to the psychotropic armamentarium.