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Biomedical subjects

T Savage

Publications and source records attributed to T Savage.

33 records · Page 2Linked to original sources
PubMed1993

Methods for measuring dermal penetration of pesticides.

The quantitation of percutaneous absorption of pesticides is required as part of the registration, re-registration or hazard assessment process. There is a paucity of regulatory guidelines in this area. This paper presents three protocols that can be used to quantitate percutaneous absorption, primarily as a result of continuous skin exposure over a period equivalent to a working day (8 hr). A rat in vivo protocol, an in vitro protocol and a human in vivo protocol are described. None of these protocols is considered to be ideal and/or to represent a preferred method. The final choice of protocol must take into account the toxicity and physicochemical properties of the test molecule as well as cost and resource/technical ability. Nevertheless, the protocols described allow percutaneous absorption to be quantitated, and it is believed that, if adopted, they will prove useful in the regulatory and research areas for the acquisition of data under standard defined conditions.

Animals↗
PubMed1988

Haemodynamic and metabolic effects of prophylactic nitroglycerin infusion in the immediate period following coronary artery bypass grafting.

This is a preliminary report of work in progress to assess the effects of prophylactic nitroglycerin infusion in patients undergoing coronary artery vein grafting. So far 14 patients have been studied. They were divided into two groups to receive either nitroglycerin (1 microgram kg-1 min-1) or placebo (5% dextrose). The infusion was commenced on removal of the aortic cross-clamp after completion of the distal anastomoses of the grafts. During cardiopulmonary bypass myocardial protection was provided by cold potassium cardioplegia and systemic hyopthermia. For 2 hours after cessation of cardiopulmonary bypass simultaneous samples of coronary sinus and femoral arterial blood were taken to estimate lactate concentrations and oxygen saturation. No differences were found between the groups. At the same times haemodynamic measurements were made. There was a statistically significant increase in cardiac index in the nitroglycerin group up to 30 minutes post cardiopulmonary bypass. There was also a statistically significant fall in systemic and pulmonary vascular resistances with no differences in systemic or pulmonary arterial pressures. There was no difference in central venous or pulmonary capillary wedge pressures. Patients receiving nitroglycerin seemed more stable cardiovascularly than those receiving placebo. In conclusion nitroglycerin improves cardiac output in the immediate post bypass period following cold potassium cardioplegia.

Bicarbonates↗
PubMed1982

Effects of divalent cations on the glycolipids from cultured mouse neuroblastoma cells.

The influence of divalent cations on glycosphingolipid metabolism was examined in the NB41A mouse neuroblastoma clonal cell line. HPLC methods were utilized to quantitate the effects on neutral glycolipids and monosialogangliosides. NB41A cells were shown to contain GM3, GM2, GM1, GD3, and GD1a by HPLC and TLC. The neutral glycosphingolipids consisted of glucosylceramide (GlcCer), lactosylceramide (LacCer), GalNAc (beta 1 leads to 4) Gal(beta 1 leads to 4)Glc(beta 1 leads to 1)Cer (GgOse3Cer), and GalNAc(beta 1 leads to 3)Gal(alpha 1 leads to 4) Gal(beta 1 leads to 4)Glc(beta 1 leads to 1)Cer (GbOse4Cer) according to their HPLC behavior. Cells grown in the presence of 1.85 mM-EGTA showed a two-to threefold increase in GM3 whereas other glycosphingolipids were only slightly affected. When cells were grown in the presence of 1.45 mM-EGTA plus 0.4 mM-EDTA a similar increase in GM3 was observed but this change was now accompanied by decreases in GM2, GM1, GgOse3Cer. The EGTA-EDTA effects were reversed when growth was in the presence of Ca2+ sufficient to bind all chelator. Mn2+ replacement reversed the chelator effects differentially; GM2 and GM1 levels were the most sensitive to increases in Mn2+ concentration; GgOse3Cer and GbOse4Cer were also sensitive, whereas GM3 was the least affected. These results suggest calcium serves an important regulatory role on GM3 levels and that manganese concentration may regulate the levels of galactosamine-containing glycolipids in mouse NB41A neuroblastoma cells.

Animals↗
PubMedDate not supplied

Synthesis and thermoelectric power of nitrogen-doped carbon nanotubes.

We have previously shown that high-purity multiwalled carbon nanotubes (pristine MWNTs) can be prepared from a mixture of xylene-ferrocene (99 at% C:1 at% Fe) inside a quartz tube reactor operating at approximately 700 degrees C. In a similar process, approximately 3 g of melamine (C3H6N6) was introduced during the growth of MWNTs to prepare nitrogen-doped nanotubes. The structural and electronic properties of nitrogen-doped MWNTs were determined by scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and thermopower measurements. The individual nitrogen-doped nanotube exhibits a bamboo-like structure and comprises 6-16 tube walls, as evidenced by HRTEM studies. The EELS measurements yielded an average nitrogen content of approximately 5 at% in the doped tubes. The thermoelectric power data of nitrogen-doped MWNTs remained negative even after exposure to oxygen for an extended period of time, suggesting that nitrogen doping of MWNTs renders them n-type, consistent with scanning tunneling spectroscopic studies on similar nanotubes.

Crystallization↗
PubMedDate not supplied

Finding agreement to limit life-sustaining treatment for children who are in state custody.

For children in state custody with extensive disabilities who reside in a skilled nursing facility, it is possible and, at times, desirable to limit treatment in the form of withholding resuscitation. With demonstration and documentation of the benefits and burdens of resuscitation for a particular child, the child protection agency will authorize a "Do Not Resuscitate" order. This article discusses the procedural as well as ethical issues involved in the process of finding agreement to limit life-sustaining treatment for children who are in state custody.

Advance Directives↗
PubMedDate not supplied

Designing a system for ambulatory obstetric case management.

The authors describe the development of critical pathways for ambulatory obstetric case management. When case management was identified as needed, but published work in outpatient obstetrics could not be found, four nurses used this opportunity to design a cost-effective system leading to quality outcomes. The driving force was the need for a format that directed comprehensive consistent care delivered by a large multidisciplinary health care team. Design issues included capturing leading edge standards of care and user friendly formats for all caregivers. Throughout a period of 2 years, a trifold format was developed for all obstetric patients, and 15 bifold formats were developed for patients with specific high-risk diagnoses. The format design facilitated cost-effective quality care and is expected to improve patient outcomes. A research study has been initiated to measure effectiveness of the design.

Ambulatory Care↗