Hydrogen Peroxide Affects the Electroretinogram of Isolated Perfused Rat Retina.

Purpose: To evaluate the effects of HO as an oxidant on the electroretinogram (ERG) in isolated rat retina.

Methods: Retinas were isolated from rat eyes and perfused with a nutrient solution. ERGs were recorded every 3 min.

Effect of the novel histamine H receptor antagonist SENS-111 on spontaneous nystagmus in a rat model of acute unilateral vestibular loss.

Background And Purpose: Histamine H receptors are expressed in the peripheral vestibular system, and their selective inhibition improves vertigo symptoms in rats with unilateral vestibular lesions. The effects of SENS-111, a selective oral H receptor antagonist with high affinity to both animal and human receptors, on vertigo symptoms was evaluated in a translational in vivo model of unilateral vestibular loss.

Experimental Approach: Pharmacokinetics of SENS-111 in rats was determined to aid dose selection for efficacy testing.

Evidence for functional GABAA but not GABAC receptors in mouse cone photoreceptors.

At the first retinal synapse, horizontal cells (HCs) contact both photoreceptor terminals and bipolar cell dendrites, modulating information transfer between these two cell types to enhance spatial contrast and mediate color opponency. The synaptic mechanisms through which these modulations occur are still debated. The initial hypothesis of a GABAergic feedback from HCs to cones has been challenged by pharmacological inconsistencies.

Safety, tolerability, pharmacokinetics and pharmacokinetic-pharmacodynamic modelling of the novel H receptor inhibitor SENS-111 using a modified caloric test in healthy subjects.

Aim: A Phase 1 study was performed to evaluate safety, pharmacokinetics (PK) and pharmacodynamics (PD) of the selective histamine H receptor antagonist SENS-111, an oral small molecule.

Methods: One hundred healthy subjects were randomized in a placebo-controlled, double-blind study evaluating single-ascending doses (SAD; 100-500 mg) and multiple-ascending doses (MAD; 50-150 mg day , 4 days; 200-250 mg day , 7 days). Effects of SENS-111 on nystagmus and vertigo induced by modified caloric tests were measured in the MAD studies.

Activation of BK and SK channels by efferent synapses on outer hair cells in high-frequency regions of the rodent cochlea.

Cholinergic neurons of the brainstem olivary complex project to and inhibit outer hair cells (OHCs), refining acoustic sensitivity of the mammalian cochlea. In all vertebrate hair cells studied to date, cholinergic inhibition results from the combined action of ionotropic acetylcholine receptors and associated calcium-activated potassium channels. Although inhibition was thought to involve exclusively small conductance (SK potassium channels), recent findings have shown that BK channels also contribute to inhibition in basal, high-frequency OHCs after the onset of hearing.

Symptomatic treatment of vestibular deficits: therapeutic potential of histamine H4 receptors.

Vestibular disorders display high prevalence and can severely impact the daily life. However, pharmacological options that would efficiently relieve the vertigo symptoms without side effects are still lacking. In the present review we briefly review the common history of histamine receptor modulation and the pharmacological therapy of vestibular disorders.

Histamine H4 receptor antagonists as potent modulators of mammalian vestibular primary neuron excitability.

Background And Purpose: Betahistine, the main histamine drug prescribed to treat vestibular disorders, is a histamine H(3) receptor antagonist. Here, we explored the potential for modulation of the most recently cloned histamine receptor (H(4) receptor) to influence vestibular system function, using a selective H(4) receptor antagonist JNJ 7777120 and the derivate compound JNJ 10191584.

Experimental Approach: RT-PCR was used to assess the presence of H(4) receptors in rat primary vestibular neurons.

Onset of cholinergic efferent synaptic function in sensory hair cells of the rat cochlea.

In the developing mammalian cochlea, the sensory hair cells receive efferent innervation originating in the superior olivary complex. This input is mediated by α9/α10 nicotinic acetylcholine receptors (nAChRs) and is inhibitory due to the subsequent activation of calcium-dependent SK2 potassium channels. We examined the acquisition of this cholinergic efferent input using whole-cell voltage-clamp recordings from inner hair cells (IHCs) in acutely excised apical turns of the rat cochlea from embryonic day 21 to postnatal day 8 (P8).

Reevaluation of dystrophin localization in the mouse retina.

PURPOSE. The roles of dystrophins in retinal physiology remain elusive. The lack of proper clustering of the potassium channel Kir4.

Modulation of hair cell efferents.

Outer hair cells (OHCs) amplify the sound-evoked motion of the basilar membrane to enhance acoustic sensitivity and frequency selectivity. Medial olivocochlear (MOC) efferents inhibit OHCs to reduce the sound-evoked response of cochlear afferent neurons. OHC inhibition occurs through the activation of postsynaptic α9α10 nicotinic receptors tightly coupled to calcium-dependent SK2 channels that hyperpolarize the hair cell.

Mammalian retinal horizontal cells are unconventional GABAergic neurons.

Lateral interactions at the first retinal synapse have been initially proposed to involve GABA by transporter-mediated release from horizontal cells, onto GABA(A) receptors expressed on cone photoreceptor terminals and/or bipolar cell dendrites. However, in the mammalian retina, horizontal cells do not seem to contain GABA systematically or to express membrane GABA transporters. We here report that mouse retinal horizontal cells express GAD65 and/or GAD67 mRNA, and were weakly but consistently immunostained for GAD65/67.

BK channels mediate cholinergic inhibition of high frequency cochlear hair cells.

Background: Outer hair cells are the specialized sensory cells that empower the mammalian hearing organ, the cochlea, with its remarkable sensitivity and frequency selectivity. Sound-evoked receptor potentials in outer hair cells are shaped by both voltage-gated K(+) channels that control the membrane potential and also ligand-gated K(+) channels involved in the cholinergic efferent modulation of the membrane potential. The objectives of this study were to investigate the tonotopic contribution of BK channels to voltage- and ligand-gated currents in mature outer hair cells from the rat cochlea.

The glutamate transporter EAAT5 works as a presynaptic receptor in mouse rod bipolar cells.

Membrane neurotransmitter transporters control the concentration of their substrate in the synaptic clefts, through the thermodynamic coupling of uptake to the movement of Na(+) and other ions. In addition, excitatory amino acid transporters (EAAT) have a Cl(-) conductance which is gated by the joint binding of Na(+) and glutamate, but thermodynamically uncoupled to the flux of glutamate. This conductance is particularly large in the retina-specific EAAT5 isoform.

Testosterone loss and estradiol administration modify memory in men.

Purpose: Little is known about the effect of androgen deprivation therapy on the brain despite the fact that sex steroid receptors are abundant in cortical brain regions that mediate memory and other cognitive functions. We characterized the impact of androgen deprivation and of subsequent estradiol therapy on the long-term and working memory of patients with prostate cancer.

Materials And Methods: Long-term memory (immediate and delayed paragraph recall tests), working memory (SOP and Trails tests) and Profile of Mood States were assessed at baseline and 4 weeks later in 18 patients with androgen independent prostate cancer beginning second line hormonal therapy with transdermal estradiol 0.

Effects of transdermal estrogen on levels of lipids, lipase activity, and inflammatory markers in men with prostate cancer.

Androgen deprivation therapy (ADT) for prostate cancer is now used in earlier disease stages and as adjuvant treatment. Recognizing and reducing the toxicity of this therapy, including worsened lipid levels and cardiovascular disease (CVD) risks, has become an important clinical concern. Oral estrogen therapy induces hypogonadism and mitigates many side effects of ADT, but has a high thrombosis risk.

Clinical outcomes of androgen deprivation as the sole therapy for localized and locally advanced prostate cancer.

Objective: To characterize the clinical outcomes of androgen deprivation therapy (ADT) as the sole therapy for localized prostate cancer, and to determine independent predictors of disease progression, as recent studies indicate an increasing use of ADT.

Patients And Methods: The records of all patients with cT1-4NXM0 adenocarcinoma of the prostate treated with ADT as the primary initial therapy at the Portland Veterans Affairs Medical Center between 1993 and 2000 were reviewed. Age, race, Charlson Health Index, family history, prostate-specific antigen (PSA) level, PSA density, digital rectal examination (DRE) findings, Gleason score, and percentage of positive biopsy cores at diagnosis were recorded for 81 patients.

High dose pulse calcitriol, docetaxel and estramustine for androgen independent prostate cancer: a phase I/II study.

Purpose: We determined the safety and preliminary efficacy of the combination of high dose pulse calcitriol (1,25-dihydroxycholecalciferol) with a standard regimen of docetaxel plus estramustine in patients with metastatic androgen independent prostate cancer.

Materials And Methods: Patients were treated with 60 microg calcitriol orally on day 1, 280 mg estramustine orally 3 times daily on days 1 to 5 and 60 mg/m docetaxel on day 2 (70 mg/m after cycle 1) every 21 days for up to 12 cycles. Patients also received 325 mg aspirin and 1 or 2 mg warfarin orally daily.

Phase II study of transdermal estradiol in androgen-independent prostate carcinoma.

Background: Oral estrogen therapy has activity in patients with hormone-naive and androgen-independent prostate carcinoma (AIPC), but its utility is limited by the associated risk of thromboembolic toxicity. Parenteral administration may be safer as it avoids "first pass" liver exposure to estrogen. The authors tested the safety and efficacy of transdermal estradiol (TDE), as well as the effect of therapy on hot flashes, sex hormones, the procoagulant cascade, and bone turnover in patients with AIPC.

Multiple cycles of intermittent chemotherapy in metastatic androgen-independent prostate cancer.

Recently, completed phase III studies demonstrated a survival benefit for a fixed number of cycles of docetaxel-containing chemotherapy treatment of androgen-independent prostate cancer (AIPC). Management of patients who respond well to initial chemotherapy for AIPC remains ill-defined. We previously reported that in a select group of such patients, retreatment with the same regimen was feasible and was associated with quality of life gains.

Imatinib mesylate and zoledronic acid in androgen-independent prostate cancer.

Objectives: To determine the safety and efficacy of zoledronic acid (Zometa) combined with imatinib mesylate (Gleevec) in patients with bone pain due to androgen-independent prostate cancer.

Methods: Fifteen patients were treated with zoledronic acid 4 mg intravenously every 28 days and imatinib mesylate 400 mg/day. The pain response, defined as a 2-point reduction in the Present Pain Intensity Scale or normalization if the initial score was 1, was the primary endpoint.

Weekly docetaxel in elderly patients with prostate cancer: efficacy and toxicity in patients at least 70 years of age compared with patients younger than 70 years.

We sought to determine whether age was significantly associated with efficacy and toxicity of weekly docetaxel in patients with metastatic androgen-independent prostate cancer (AIPC). Individual patient data were pooled from 2 phase II clinical trials of weekly docetaxel 36 mg/m(2) for 6 of every 8 weeks in men with metastatic AIPC. Baseline characteristics and outcome measures of men > 70 years of age (n = 52) were compared with patients < 70 of age (n = 34) using Pearson c2 test for categoric variables, Mann-Whitney U test for continuous variables, and log-rank test of Kaplan-Meier estimates for time-dependent variable.

Targeting FSH in androgen-independent prostate cancer: abarelix for prostate cancer progressing after orchiectomy.

Objectives: To determine the efficacy of the gonadotropin-releasing hormone antagonist abarelix in patients with androgen-independent prostate cancer progressing after orchiectomy and to measure its effect on serum follicle-stimulating hormone (FSH).

Methods: Sixteen patients with prostate cancer progressing after orchiectomy received abarelix-depot 100 mg by intramuscular injection on days 1, 15, and 29 and then every 28 days for up to 24 weeks (52 weeks in patients who met the criteria for a prostate-specific antigen [PSA] response after 24 weeks). PSA response was the primary endpoint and was defined as a 50% reduction confirmed 4 weeks later.

Polymorphisms of GSTT1 and related genes in head and neck cancer risk.

Background: Glutathione S-transferase T1 detoxifies some environmental carcinogens while activating others and is deleted in 15% to 38% of humans. We sought to determine whether GSTT1 genotype and genotypes of several related genes are associated with risk of squamous cell carcinoma of the head and neck (HNSCC).

Methods: Somatic genotypes for GSTT1, GSTM1, GSTP1, and CYP1A1 were determined in 283 individuals with HNSCC and 208 population-based controls.

Intermittent chemotherapy in metastatic androgen-independent prostate cancer.

Intermittent use of chemotherapy for androgen-independent prostate cancer (AIPC) instead of treatment until disease progression may reduce toxicity. We prospectively tested this approach in eight AIPC patients responding to calcitriol plus docetaxel who reached a serum prostate-specific antigen (PSA) <4 ng ml(-1). Chemotherapy was suspended until a rise in PSA>/=50% and 1 ng ml(-1).