Search PubMed⌕ Search

Biomedical subjects

B Carter

Publications and source records attributed to B Carter.

At least 55 records · Page 3Linked to original sources
PubMed1995

Characterization of TrkB receptor-mediated signaling pathways in rat cerebellar granule neurons: involvement of protein kinase C in neuronal survival.

TrkB belongs to the Trk family of tyrosine kinase receptors and mediates the response to brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5). Here, we report that both truncated and full-length forms of TrkB receptors are expressed in developing cerebellar granule neurons. BDNF and NT-4/5 increased the survival of cultured cerebellar granule neurons. BDNF and NT-4/5 also induced an autophosphorylation of TrkB receptors and subsequently resulted in a phosphorylation and binding of phospholipase C-gamma (PLC-gamma) and SH2-containing sequence to the autophosphorylated TrkB receptors. Both contain src homology 2 (SH2) regions. In keeping with a signaling function of PLC-gamma, BDNF increased the phosphatidylinositol (PI) turnover and elevated intracellular calcium levels. To investigate the involvement of protein kinase C (PKC) in the survival of granular neurons, we show here activation of PKC after BDNF or TPA treatment and blocking of the observed survival-promoting effects of BDNF and TPA with calphostin C, a specific PKC inhibitor. In addition, BDNF activated c-ras in a concentration-dependent manner. These results suggest that two different pathways, the c-ras and the PLC-gamma pathway, are activated by TrkB receptors in primary neurons and that PKC activation is involved in the survival promoting effect of BDNF.

Animals↗
PubMed1995

A comparison of two transcutaneous monitors for the measurement of arterial PO2 and PCO2 in neonates.

We examined the ability of two transcutaneous devices (Fastrac, Sensormedics Corporation, Yorba Linda, California, U.S.A. and Hewlett Packard M1018A, Hewlett Packard Component Monitoring System, Hewlett Packard, North Hollywood, U.S.A.) to measure arterial PCO2 and PO2 in neonates. Thirty-seven neonates had transcutaneous oxygen measured with the Hewlett Packard (HPO2 group), 38 neonates had transcutaneous carbon dioxide measured with the Hewlett Packard (HPCO2 group) and the Fastrac was used on 27 neonates (FTCO2 group). Both devices were operated with electrode temperatures of 43.5 degrees C although an additional ten subjects were studied using the Fastrac with an electrode temperature of 43.0 degrees C. The mean differences (transcutaneous--arterial) and upper and lower limits of agreement were calculated for each group. For the HPO2 group they were 3.78 mmHg (-12.23 to 19.80 mmHg), for the HPCO2 group they were 0.40 mmHg (-4.50 to 5.30 mmHg) and for the FTCO2 they were -0.96 mmHg (-7.85 to 5.92 mmHg). For the Fastrac group at an electrode temperature of 43.0 degrees C the mean difference and limits of agreement were -1.00 mmHg and -4.58 mmHg to 2.58 mmHg. The average sensitivity and specificity for both machines for the detection of hypocarbia were 82% and 92% respectively while for hypercarbia they were 90% and 94% respectively. For hypoxaemia, the sensitivity and specificity were 40% and 94% while for hyperoxaemia the sensitivity and specificity were 83% and 97%. We conclude that both machines provide a useful supplement to arterial PCO2 measurements and the Fastrac performs better at 43.0 degrees C. The measurement of PO2 is less accurate but is still of clinical use.

Blood Gas Monitoring, Transcutaneous↗
PubMed1993

An alarm for monitoring CPAP.

We have built a device for use within the hospital and at home that is designed to warn of circuit disconnection when used in conjunction with continuous positive airway pressure (CPAP) therapy delivered via ventilators or CPAP generating systems. The Royal Children's Hospital CPAP alarm is a compact, battery operated alarm and monitor of circuit pressure. The device includes intrinsic safety features including a safety blow-off valve, a high pressure alarm and design features that make the device practical, safe and easy to use by both trained hospital personnel and home care attendants with limited training.

Equipment Design↗
PubMed1993

An appraisal of techniques for administration of gaseous nitric oxide.

Gaseous nitric oxide (NO) is a potent selective pulmonary vasodilator. When mixed with O2 for more than 10-15 minutes it forms toxic amounts of nitrogen dioxide (NO2). We describe two techniques to administer 20 parts per million (ppm) during mechanical ventilation. A technique using flows of NO and O2 at low pressure to drive a Siemens Servo 900C ventilator provided a constant inspired concentration of NO. Another technique in which NO was added to the inspiratory limb of a Siemens Servo 900C ventilator driven by high pressure oxygen provided a highly variable concentration (9-53 ppm) of inspired NO.

Anesthesia, Inhalation↗
PubMed1992

Evaluation of a heart disease survey and education program for general practitioners.

In 1989 we mailed a questionnaire to all 461 general practitioners (GPs) identified as currently practising in the Eastern Metropolitan Health Region of Sydney. This was the first phase of a program to assess, amplify and reassess GPs' knowledge of the risk factors for heart disease and measure their attitudes and beliefs about their role in the prevention of cardiovascular disease. The second phase was an education program designed to meet the needs identified by the first questionnaire. Phase three was a postintervention questionnaire. Fifty-six per cent (260/461) responded to the first questionnaire. This follow-up group were mailed the second questionnaire, to which 52 per cent (135/260) responded. Thirty per cent of the original sample (139/461) attended the education program and 30 per cent (79/260) of the follow-up group did so. At baseline, the respondents' level of risk factor knowledge was good, but after the education program there was still a large gap between what they said they knew and the amount of advice they said they would give to patients. The only significant increase in the amount of advice after the intervention was to 'control blood pressure'. This applied whether the GP had participated in the intervention or not. When GPs were asked how often in the last month they had actually given advice to reduce cardiovascular disease risk, program attenders reported offering it more frequently than nonattenders. We also attempted to determine whether any particular demographic characteristics could predict respondents to the questionnaires and/or the educational program.

Australia↗
PubMed1992

Accuracy of the BoMED NCCOM3 bioimpedance cardiac output monitor during induced hypotension: an experimental study in dogs.

Changes in thoracic electrical bioimpedance during the cardiac cycle are utilised by the BoMed NCCOM3 monitor to measure cardiac output (COTEB). The technique provides a continuous noninvasive measurement but it has not been widely accepted. To determine the accuracy of the monitor, we compared its measurement with cardiac output measured by dye dilution (CODD) during induced hypotension and recovery in 23 dogs. After calibration of the NCCOM3 monitor during a resting state in each dog [mean blood pressure 112 +/- 17 (SD), mean CODD 3.22 +/- 0.99 l/min], the mean difference (COTEB-CODD) between paired measurements at the nadir of hypotension (blood pressure 55 +/- 24 mmHg) was 0.29 +/- 0.47 l/min whose limits of agreement (mean difference +/- 2 SD) were + 111.8% and -59.1% of the mean hypotensive CODD (1.10 +/- 0.66 l/min). Upon recovery from hypotension (mean blood pressure 102 +/- 20 mmHg), the mean difference between paired measurements was -0.28 +/- 0.66 l/min, whose limits of agreement were +44.1% and -67.8% of the mean CODD (2.36 +/- 1.01 l/min). The mean difference between the two techniques is too variable and excessive to permit substitution of one technique for the other. These results do not support the accuracy and reliability of the BoMed NCCOM3 cardiac output monitor.

Animals↗
PubMed1992

Transforming growth factor e: amino acid analysis and partial amino acid sequence.

Our previous studies have demonstrated that transforming growth factor e (TGFe) acts as a mitogen for epithelial and fibroblastic cells in both monolayer and soft agar. We have also identified TGFe in both normal and neoplastic tissues of mostly epithelial origin, and in body fluids. In this study we report on the purification of TGFe to homogeneity from bovine kidney using a multistep purification protocol which utilizes high performance electrophoresis chromatography in the final step. Amino acid analysis of TGFe revealed high content of proline, aspartate and glutamate. Examination of partial amino acid sequence indicated no similarity to other, already characterized, growth factors.

Adrenal Cortex Neoplasms↗
PubMed1991

Development of a micromanometer-tip catheter to record high-fidelity pressures during cine-gated NMR without significant image distortion.

We report a new micromanometer-tip catheter to record high-fidelity pressures during cine-gated gradient echo NMR imaging in an intact animal model. Of the various metals and alloys tested for use in its construction, brass produced the smallest NMR artifact with minimal magnification. With the use of this new catheter design, there was little signal loss and no distortion of endocardial borders during imaging.

Alloys↗