Biomedical subjects

James A Sipp

Publications and source records attributed to James A Sipp.

2 recordsLinked to original sources

PubMed2005

Gap junction-mediated intercellular biochemical coupling in cochlear supporting cells is required for normal cochlear functions.

Dysfunction of gap junctions (GJs) caused by mutations in connexin26 (Cx26) and Cx30 accounts for nearly half of all cases of hereditary nonsyndromic deafness cases. Although it is widely held that GJs connecting supporting cells in the organ of Corti mainly provide ionic pathways for rapid removal of K+ around the base of hair cells, the function of GJs in the cochlea remains unknown. Here we show that GJs were not assembled in the supporting cells of the organ of Corti until 3 days after birth in mice and then gradually matured to connect supporting cells before the onset of hearing. In organotypic cochlear cultures that were confirmed to express GJs, GJs mediated the propagation of intracellular Ca2+ concentration waves in supporting cells by allowing intercellular diffusion of inositol 1,4,5-trisphosphate. We found that a subset of structurally mild Cx26 mutations located at the second transmembrane region (V84L, V95M, and A88S) and a Cx30 mutation located at the first cytoplasmic segment (T5M) specifically affect the intercellular exchange of larger molecules but leave the ionic permeability intact. Our results indicated that Cx26 and Cx30 mutations that are linked to sensorineural deafness retained ionic coupling but were deficient in biochemical permeability. Therefore, GJ-mediated intercellular exchange of biochemically important molecules is required for normal cochlear functions.

Animals↗

PubMed2005

Pediatric parotitis: a 5-year review at a tertiary care pediatric institution.

BACKGROUND: Parotitis is a well recognized entity in the adult population, however there are very few studies concerning the clinical presentation and management of this condition in children. OBJECTIVES: To characterize pediatric parotitis in a tertiary care setting, with the goal of clarifying management recommendations and outcomes. METHODS: The charts of all pediatric patients with a diagnosis of parotitis treated at a tertiary care academic institution from 1999 to 2004 were reviewed. The management of inpatients and outpatients were characterized to define differences in presentation and care. RESULTS: Twenty-one children (6 months-15 years) with a diagnosis of parotitis were identified. Thirteen (62%) children were treated as inpatients, of which seven (54%), had significant medical co-morbidities. The most common clinical presentations of the inpatient group included dehydration (46%), fever (38%) and leukocytosis (46%). Two inpatients (15%) required surgical drainage due to abscess formation. Eight children (38%) were treated as outpatients, none with associated co-morbidity, fever, leukocytosis, or complication due to infection. All outpatients were treated with oral antibiotics or conservative therapy with eventual resolution. CONCLUSIONS: Parotitis in the pediatric population is uncommon. The presence of a significant co-morbidity, fever, or leukocytosis may require inpatient therapy and imaging if patients fail to improve with medical therapy. Other than abscess drainage, surgery for parotitis in children is not routinely recommended.

Abscess↗