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Biomedical subjects

J Oliver

Publications and source records attributed to J Oliver.

At least 55 records · Page 3Linked to original sources
PubMed1999

Extracellular matrix regulates apoptosis in mammary epithelium through a control on insulin signaling.

Adherent epithelial cells require interactions with the extracellular matrix for their survival, though the mechanism is ill-defined. In long term cultures of primary mammary epithelial cells, a laminin-rich basement membrane (BM) but not collagen I suppresses apoptosis, indicating that adhesion survival signals are specific in their response (. J. Cell Sci. 109:631-642). We now demonstrate that the signal from BM is mediated by integrins and requires both the alpha6 and beta1 subunits. In addition, a hormonal signal from insulin or insulin-like growth factors, but not hydrocortisone or prolactin, is necessary to suppress mammary cell apoptosis, indicating that BM and soluble factors cooperate in survival signaling. Insulin induced autophosphorylation of its receptor whether mammary cells were cultured on collagen I or BM substrata. However, both the tyrosine phosphorylation of insulin receptor substrate-1 and its association with phosphatidylinositol 3-kinase were enhanced in cells cultured on BM, as was the phosphorylation of the phosphatidylinositol 3-kinase effector, protein kinase B. These results suggest a novel extracellular matrix-dependent restriction point in insulin signaling in mammary epithelial cells. The proximal signal transduction event of insulin receptor phosphorylation is not dependent on extracellular matrix, but the activation of downstream effectors requires adhesion to BM. Since phosphatidylinositol 3-kinase was required for mammary epithelial cell survival, we propose that a possible mechanism for BM-mediated suppression of apoptosis is through its facilitative effects on insulin signaling.

Animals↗
PubMed1999

Stimulation of uncoupling protein 1 expression in brown adipocytes by naturally occurring carotenoids.

OBJECTIVE: To assess the effect of naturally occurring carotenoids on brown adipocyte proliferation and differentiation. The rationale behind is that certain carotenoids have provitamin A activity in mammals, and that one of the active forms of vitamin A, (retinoic acid) is known to behave as a transcriptional activator of the key gene for brown fat thermogenesis, the one encoding the uncoupling protein thermogenin (UCP1). DESIGN: Confluent primary cultures of mice brown adipocytes were treated with various concentrations of carotenoids. Cell morphology, total culture protein content, the DNA synthesis rate, and the levels of UCP1, retinoic acid receptor alpha (RARalpha) and retinoid X receptor alpha (RXRalpha) were analysed. RESULTS: Treatment with beta-carotene, alpha-carotene and lutein promoted UCP1 expression in a dose-dependent manner, with an effectiveness that was related to their potency as vitamin A precursors. Cell morphology, total culture protein content at confluence and DNA synthesis rate were unaffected after carotenoid treatment up to 10 microM. CONCLUSION: The results indicate that carotenoids can positively affect the expression of UCP1 without altering brown adipocyte proliferation.

Adipocytes↗
PubMed1999

Do mite avoidance measures affect mite and cat airborne allergens?

BACKGROUND: Effective mite allergen avoidance measures are presumed to reduce airborne allergens yet the quantity in the air is rarely measured. OBJECTIVE: To monitor airborne allergen during a placebo-controlled mite allergen avoidance study. METHODS: Bedrooms of 56 atopic asthmatic children were randomly allocated to hot washing and encasing covers + acaricide (active regime) or placebo treatment. Dust was collected from the mattress, bedding and carpets; airborne allergen was measured using Casella samplers and dust settling in open Petri dishes. Der p 1, Der p 2 and Fel d 1 were measured. RESULTS: After 24 weeks of mite allergen avoidance the Casella air-samplers collected Der p 1 less frequently in active than placebo-treated bedrooms (0 vs. 29%, P<0.05) and Petri dishes in the active group collected less than baseline (0.2 vs. 0.6 ng/day P<0.05). Homes without cats had less cat allergen than cat-owning homes and when actively treated for 24 weeks showed a greater reduction (P = 0.03) in mattress cat allergen than the placebo group. CONCLUSION: Encasing covers and hot washing of bed linen reduced mite aeroallergen (and mattress cat allergen in the absence of cats). This could mean dual benefits to a patient sensitive to both mite and cat.

Air Pollutants↗
PubMed1999

The role of computed tomography in the diagnosis of arterial gas embolism in fatal diving accidents in Tasmania.

Four cases of fatal diving accidents in Tasmania are presented, highlighting the role of CT in the investigation of diving fatalities. The CT technique allows rapid diagnosis when arterial gas embolism (AGE) is suspected. The traditional method of investigation, underwater autopsy, is a difficult procedure that requires specialized training in which the subtle diagnosis of AGE may be completely missed. Facilities for performing underwater autopsies are normally available only in tertiary referral centres, and therefore the diagnosis of AGE may be missed due to lack of facilities. The use of CT in the diagnosis of AGE in divers was first utilized in the early 1980s but has still not become widely adopted in forensic practice. This radiological technique has the advantage of being sensitive, quick, reliable, readily available and provides a permanent record. For hospitals that do not have a resident forensic pathologist, a CT scan can be easily performed and interpreted to eliminate the possibility of AGE. There are a number of pitfalls in the diagnosis of AGE with CT, particularly intravascular gas production following postmortem fermentation and off-gassing. Awareness of these pitfalls will help the radiologist in making a correct diagnosis of AGE.

Accidents↗
PubMed1999

Glenomandibular muscle band in the human TMJ: a muscular antagonist to Bennett movement?

The medial aspects of ten adult TMJs were dissected using an inferior, rather than the more traditional lateral approach. Additionally, five 25 mm3 cubes of cadaver tissue with the mandibular condyle at their center were serially cryosected and photographed. Axial MRI scans were also taken of the TMJs of two living subjects. A band of fibromuscular tissue was found to run horizontally from the medial pole of the mandibular condyle to insert in an area of the sphenoid in front of the squamotympanic fissure. It is postulated that this glenomandibular band acts as a muscular antagonist to lateral Bennett movement.

Adult↗
PubMed1999

Measuring quality of life in secure care: comparison of mentally ill and personality disordered patients.

Improving quality of life for patients is emerging as a legitimate goal for UK inpatient forensic mental health services. The Lancashire Quality of Life Profile (LQOLP), which has been used widely to measure well-being in community settings, was trialed on an inpatient population being cared for under conditions of high security. Two groups of male patients, drawn from within the same institution but with markedly different clinical conditions, i.e. schizophrenia (N = 47) and personality disorder (N = 48), were interviewed using the LQOLP. Although both groups had been cared for under largely similar environmental conditions over similar lengths of time (9.5 years), the subjective global well-being of the two groups differed systematically as did other objective and subjective well-being measures. However, analysis found that the variations in global well-being could not be attributed readily to factors covered by the interview, including either current mood or personality. Possible reasons for these findings and implications for the use of the LQOLP under conditions of high security are discussed.

Adult↗
PubMed1999

Developmental regulation of Bcl-2 family protein expression in the involuting mammary gland.

Epithelial cells within the mammary gland undergo developmental programmes of proliferation and apoptosis during the pregnancy cycle. After weaning, secretory epithelial cells are removed by apoptosis. To determine whether members of the Bcl-2 gene family could be involved in regulating this process, we have examined whether changes in their expression occur during this developmental apoptotic program in vivo. Bax and Bcl-x were evenly expressed throughout development. However, expression of Bak and Bad was increased during late pregnancy and lactation, and the proteins were present during the time of maximal apoptotic involution. Thereafter, their levels declined. In contrast, Bcl-w was expressed in pregnancy and lactation but was downregulated at the onset of apoptosis. Bcl-2 was not detected in lactating or early involuting mammary gland. Thus, the pro-apoptotic proteins Bax, Bak and Bad, as well as the death-suppressors Bcl-x, Bcl-2 and Bcl-w, are synthesised in mouse mammary gland, and dynamic changes in the expression profiles of these proteins occurs during development. To determine if changes in Bak and Bcl-w expression could regulate mammary apoptosis, their effect on cultured mouse mammary epithelial cells was examined in transient transfection assays. Enforced expression of Bak induced rapid mammary apoptosis, which could be suppressed by coexpression of Bcl-w. In extracts of mammary tissue in vivo, Bak heterodimerized with Bcl-x whereas Bax associated with Bcl-w, but Bak/Bcl-w heterodimers were not detected. Thus, Bak and Bcl-w may regulate cell death through independent pathways. These results support a model in which mammary epithelial cells are primed for apoptosis during the transition from pregnancy to lactation by de novo expression of the death effectors Bak and Bad. It is suggested that these proteins are prevented from triggering apoptosis by anti-apoptotic Bcl-2 family proteins until involution, when the levels of Bcl-w decline. Our study provides evidence that regulated changes in the expression of cell death genes may contribute to the developmental control of mammary apoptosis.

Animals↗
PubMed1998

The outcome of patients with upper airway obstruction transported to a regional paediatric intensive care unit.

UNLABELLED: The diagnoses, transfer, management and outcome of patients with upper airway obstruction (UAO) admitted from district general hospitals (DGH) to a regional paediatric intensive care unit were retrospectively reviewed over a 3.5-year period. Sixty-seven patient episodes were analysed. Fifty-two cases (78%) underwent tracheal intubation prior to transport with a low morbidity for both procedures. The most common diagnosis was viral croup (n = 34, 51%) with a median duration of intubation of 5 days, with subglottic stenosis being the next most common category (n = 10, 15%), median duration of intubation 7 days. Inhaled budesonide was used prior to intubation in 12 (35%) of those with croup, and inhaled bronchodilators in 28%, possibly reflecting diagnostic uncertainty. Patients with croup treated with budesonide were significantly less likely to require intubation (P = 0.04). The re-intubation rate for patients with viral croup was uncomfortably high at 16% (4/25) despite the routine use of prednisolone throughout the intubation period. Successful extubation of patients with viral croup could not be predicted by age (P = 0.31), length of intubation (P = 0.94), endotracheal tube size, (P = 0.60) abnormalities on the chest X-ray (P = 1.0), or presence of secondary bacterial infection (P = 0.23). CONCLUSION: Although viral croup remains the most common diagnostic category presenting at the DGH level with severe UAO, a wide range of other diagnoses is seen. Despite clear evidence of benefit, steroid administration to children presenting at the DGH with viral croup has not become routine practice. Once intubated, no reliable predictors of successful extubation were found amongst this patient group.

Airway Obstruction↗
PubMed1998

Occurrence of Ixodes scapularis (Acari: Ixodidae) on a selected segment of the Appalachian Trail.

A 918-km section of the Appalachian National Scenic Trail from the West Virginia-Maryland border to the Massachusetts-Vermont border was surveyed for the presence of Ixodes scapularis Say. The trail and its edges were drag-sampled during 4 hikes between May and October 1991. Trips were designed to survey areas of the Appalachian Trail when I. scapularis might be questing and to revisit states endemic for Lyme disease during differing times. After sampling for ticks, meteorological and ecological characteristics were measured at each site. In total, 1,776 km of the Appalachian Trail were hiked during 88 d and resulted in sampling 489 sites. All life stages of Ixodes scapularis (n = 46) were collected from 21 sites within a 331-km range of the Appalachian Trail between Salisbury, CT, to Delaware Water Gap, PA. This segment of Appalachian Trial is easily accessible to a large urban population and should be posted with tick warning signs to alert the public to the presence of I. scapularis.

Animals↗
PubMed1997

Ovarian torsion associated with granulosa-theca cell tumor in a mare.

A 12-year-old Morgan mare was examined because of stallion-like behavior of 45 days' duration. Palpation per rectum and transrectal ultrasonographic examination revealed a large left ovary with multiple cystic areas and crepitus. A granulosa-theca cell tumor was suspected. During hospitalization for further evaluation of the affected ovary, the mare developed signs of abdominal pain. Exploratory surgery revealed a large left ovary, which was black with a necrotic and friable surface, and a 720 degrees clock-wise torsion of the ovarian pedicle. Torsion was corrected, and oophorectomy was performed. The mare recovered satisfactorily from surgery. Histologic diagnosis was granulosatheca cell tumor with marked diffuse necrosis. To our knowledge, torsion of the ovarian pedicle has not been reported in the veterinary literature. However, it is not uncommon in women. Ovarian torsion seems to develop in association with neoplasia, cysts, and ovarian hyperstimulation syndrome. Ovarian torsion should be considered as a differential diagnosis for mares with a known ovarian pathologic change such as neoplasia or abscess if signs of abdominal pain are evident.

Animals↗
PubMed1997

[Stent implantation in systemic venous baffle obstruction after Mustard-type operation repair in an adult].

Late systemic venous baffle obstruction after Mustard repair for complete transposition of the great arteries is a recognized complication. Balloon-expandable intravascular stents have previously been used to relieve systemic baffle narrowing in children. We report a successful stent implantation to relieve symptomatic superior vena cava obstruction and baffle dehiscence after Mustard repair in an adult patient. She had been turned down for surgery due to right ventricular dysfunction. Eighteen months after the procedure, she remains symptomless.

Adult↗