Functional heterogeneity of cholangiocytes.

The objective of this article is to summarize the findings related to the notion that cholangiocytes, within small and large intrahepatic ducts, are heterogeneous regarding (1) morphology; (2) secretion in response to hormones and peptides and to bile acids; and (3) proliferation in response to injury or toxins, including bile duct ligation (BDL), acute carbon tetrachloride (CCl 4 ) administration, chronic feeding of bile salts (i.e., taurocholate [TC] or taurolithocholate [TLC]) or alpha-naphthylisothiocyanate (ANIT).

Protein kinase C mediates potentiation of synaptic transmission by phorbol ester at parallel fibers in the dorsal cochlear nucleus.

Many cells in the outer two layers of the dorsal cochlear nucleus (DCN) express high levels of the phospholipid-activated, calcium dependent kinase, protein kinase C (PKC), an enzyme that can phosphorylate numerous proteins involved in neurotransmission and postsynaptic signaling. We investigated the effects of stimulating PKC with phorbol esters (phorbol 12-13 diacetate; PDAc) on parallel fiber synaptic transmission in brain slices of the guinea pig DCN. Phorbol esters increased the amplitude of the postsynaptic components of the field potential, including the excitatory post-synaptic field potential (fEPSP) and the population spike following electric stimulation of parallel fibers.

Insulin inhibits secretin-induced ductal secretion by activation of PKC alpha and inhibition of PKA activity.

Insulin stimulates canalicular bile flow by interaction with hepatocytes. Insulin regulates the function of a number of epithelia through activation and membrane translocation of Ca(2+)-dependent PKC isoforms. No information exists regarding insulin regulation of ductal bile secretion.

Impact of cochlear implants on the functional health status of older adults.

Objectives: To assess the impact of cochlear implantation on quality of life changes in older adults aged 50 years and above.

Study Design: Retrospective study by questionnaire and chart review.

Methods: Forty-seven patients aged 50 to 80 years (mean age, 63.

Stimulation of alpha2-adrenergic receptor inhibits cholangiocarcinoma growth through modulation of Raf-1 and B-Raf activities.

Growth factor signaling, mediated by the mitogen-activated protein kinase (MAPK) cascade, induces cell mitosis. Adenosine 3',5'-monophosphate (cAMP) may inhibit or stimulate mitosis (depending on the cell type) through the activation of MAPK and Raf proteins. Among Raf proteins, Raf-1 and B-Raf differentially regulate mitosis.

Ursodeoxycholate and tauroursodeoxycholate inhibit cholangiocyte growth and secretion of BDL rats through activation of PKC alpha.

Accumulating bile acids (BA) trigger cholangiocyte proliferation in chronic cholestasis. The aim of this study was to determine if ursodeoxycholate (UDCA) or tauroursodeoxycholate (TUDCA) chronic feeding prevents the increased cholangiocyte growth and secretion in bile duct-ligated (BDL) rats, if UDCA and TUDCA effects are associated with increased cholangiocyte apoptosis, and to determine if this inhibition is dependent on increased intracellular Ca(2+) ([Ca(2+)](i)) and activation of protein kinase C (PKC) alpha. Immediately after BDL, rats were fed UDCA or TUDCA (both 275 micromol/d) for 1 week.

Bile acid feeding increased proliferative activity and apical bile acid transporter expression in both small and large rat cholangiocytes.

Bile acids (BA) enter cholangiocytes by the Na(+)-dependent apical BA transporter (ABAT). By this mechanism, taurocholate (TC) and taurolithocholate (TLC) increase cholangiocyte proliferation. No in vivo studies exist regarding the anatomical sites involved in BA-regulation of cholangiocyte growth.

Squamous cell carcinoma of the temporal bone: a radiographic-pathologic correlation.

Objective: To assess the utility of a previously proposed staging system for patients with primary squamous cell carcinoma of the temporal bone.

Methods: Retrospective chart review of 15 patients treated for squamous cell carcinoma of the temporal bone over a 13-year period at an academic tertiary referral center. A review of the medical and surgical records, radiographic studies, and surgical pathology reports allowed for an evaluation of the University of Pittsburgh staging system.

Regression of cholangiocyte proliferation after cessation of ANIT feeding is coupled with increased apoptosis.

Cholangiocyte proliferation and loss through apoptosis occur in cholestatic liver diseases. Our aim was to determine the mechanisms of apoptosis in an animal model of ductal hyperplasia. Rats were fed alpha-naphthylisothiocyanate (ANIT) for 2 wk and subsequently fed normal chow for 1, 2, and 4 wk.

Hearing rehabilitation using the BAHA bone-anchored hearing aid: results in 40 patients.

Objective: This study evaluates the U.S. experience with the first 40 patients who have undergone audiologic rehabilitation using the BAHA bone-anchored hearing aid.

Gastrin inhibits cholangiocarcinoma growth through increased apoptosis by activation of Ca2+-dependent protein kinase C-alpha.

Background/aims: We determined the role of gastrin in the regulation of cholangiocarcinoma growth.

Methods: We evaluated for the functional presence of cholecystokinin (CCK)-B/gastrin receptors in the cholangiocarcinoma cell lines, Mz-ChA-1, HuH-28 and TFK-1. We determined the effect of gastrin on the growth of Mz-ChA-1, HuH-28 and TFK-1 cells.

Targeted disruption of the Kvlqt1 gene causes deafness and gastric hyperplasia in mice.

The KvLQT1 gene encodes a voltage-gated potassium channel. Mutations in KvLQT1 underlie the dominantly transmitted Ward-Romano long QT syndrome, which causes cardiac arrhythmia, and the recessively transmitted Jervell and Lange-Nielsen syndrome, which causes both cardiac arrhythmia and congenital deafness. KvLQT1 is also disrupted by balanced germline chromosomal rearrangements in patients with Beckwith-Wiedemann syndrome (BWS), which causes prenatal overgrowth and cancer.

Effects of deafferentation on the electrophysiology of ventral cochlear nucleus neurons.

When cochlear pathology impairs the afferent innervation of the ventral cochlear nucleus (VCN), electrical responses of the auditory brainstem are altered and changes in cell and synaptic morphology are observed. However, the impact of deafferentation on the electrical properties of cells in the VCN is unknown. We examined the electrical properties of single neurons in the anterior and posterior VCN following bilateral cochlear removal in young rats.

Survey of symptoms, respiratory function, and immunology and their relation to glutaraldehyde and other occupational exposures among endoscopy nursing staff.

Objectives: To find the nature and incidence of symptoms experienced by a large sample of hospital endoscopy nurses. To find whether nurses in endoscopy units develop asthma under current working conditions in endoscopy units. To obtain analytically reliable data on exposure concentrations of glutaraldehyde (GA) vapour in endoscopy units, and to relate them to individual hygiene and work practices.

Cost-utility analysis of the cochlear implant in children.

Context: Barriers to the use of cochlear implants in children with profound deafness include device costs, difficulty assessing benefit, and lack of data to compare the implant with other medical interventions.

Objective: To determine the quality of life and cost consequences for deaf children who receive a cochlear implant.

Design: Cost-utility analysis using preintervention, postintervention, and cross-sectional surveys conducted from July 1998 to May 2000.

Environmental exposure to air pollution and allergens and peak flow changes.

Laboratory-based studies have shown that ozone and nitrogen dioxide can potentiate the effect of allergen in sensitized asthmatic subjects, but it is not known whether this interaction is important under natural exposure conditions. Thirty-five subjects with clinical diagnoses of asthma or chronic obstructive pulmonary disease and with a provocative dose causing a 20% fall in forced expiratory volume in one second methacholine <12.25 micromol (using the Yan method) kept peak expiratory flow (PEF) records for a 4-week period during late summer, with concurrent measurement of spore and pollen counts and pollution levels.

Immune-mediated inner ear disease.

Immune-mediated inner ear disease (IMIED) is a syndrome that includes the subacute onset of sensorineural hearing loss, often accompanied by vertigo and tinnitus. This constellation of symptoms may occur as a primary disorder in which no other organ involvement is evident, or it may complicate certain systemic conditions, including Wegener's granulomatosis, Cogan's syndrome, polyarteritis nodosa, and systemic lupus erythematosus. The precise disease mechanisms remain undefined, largely because of the difficulty obtaining relevant tissue specimens in untreated patients.

Cholinergic system modulates growth, apoptosis, and secretion of cholangiocytes from bile duct-ligated rats.

Background & Aims: To investigate the role of the cholinergic system in regulation of cholangiocyte functions, we evaluated the effects of vagotomy on cholangiocyte proliferation and secretion in rats that underwent bile duct ligation (BDL rats).

Methods: After bile duct ligation (BDL), the vagus nerve was resected; 7 days later, expression of M3 acetylcholine receptor was evaluated. Cholangiocyte proliferation was assessed by morphometry and measurement of DNA synthesis.

Attempting to control mite allergens with mechanical ventilation and dehumidification in British houses.

Background: Allergen avoidance is of considerable interest in the treatment and even prevention of asthma. Attempts to control house dust mites have included environmental manipulation in homes in an attempt to reduce humidity below a level that favors mite survival. This appears to have some benefit in Scandinavia, but a previous attempt with mechanical ventilation heat pump recovery (MVHR) units in the UK failed to achieve the desired results.