Search PubMed⌕ Search

Biomedical subjects

S J Phillips

Publications and source records attributed to S J Phillips.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Myocardial morphology and blood flow distribution in chronic volume-overload hypertrophy in dogs.

In this study we investigated myocardial structural alterations and regional myocardial blood flow in chronic volume-overload induced left ventricular hypertrophy in the dog. Moderate hypertrophy (28%) was produced by inserting a shunt between the left subclavian artery and the left atrial appendage in 7 dogs (LVH), while a sham operation was performed on 5 control dogs (C). At a paced heart rate of 100 beats/min there were no differences in blood-flow distribution to the subendocardium (ENDO) mid-myocardium (MYO) or subepicardium (EPI) or in ENDO/EPI ratios between the two groups of dogs. Following adenosine-induced coronary vasodilatation (1 mg/kg/min), there was a relative shift in blood flow away from the ENDO in the LVH dogs so that the ENDO/EPI ratio was reduced. Analysis of the microvascular bed and myocyte cross-sectional area in the same three regions of interest revealed a significant reduction in capillary density in the ENDO region of the hypertrophied hearts when compared to controls (LVH = 2463 +/- 10, C = 2773 +/- 75 caps/mm2) and a corresponding increase in myocardial cell cross-sectional area (LVH = 262 +/- 10, C = 233 +/- 36 microns 2). The reduction in capillary density in LVH may be explained on the basis of increased muscle growth without appropriate capillary proliferation indicating an inadequate neovascular response to this form of overload. The results also indicate that blood-flow distribution abnormalities may not be detected at resting flow with moderate LVH produced by volume overload.

Adenosine↗
PubMedDate not supplied

A disposable heart-lung machine. Results of animal testing.

A small wave propagation pump (WPP) was incorporated into oxygenators to create a disposable heart-lung machine. The WPP provides undirectional micropulsatile laminar flow of 8 L/min against 800 mmHg. The smaller WPP can generate 4 L/min against 400 mmHg (cardioplegia), or reversed, and can create up to 150 mmHg negative pressure for suction. Power needs were 110 volts and 0.5 amps or 24 volts DC and 1.5 amps. The WPP is self priming (20 cc) and de-aired in less than 3 min. Seven dogs (average weight, 36 kg) were supported for 3 hrs. Flows could accurately be adjusted from 0.005 to 8 L/min. Flow through the oxygenator and perfusion circuit averaged 3.1 L/min (2.0 to 4 L/min). Serial analysis of blood samples showed minimal hemolysis and no significant change in hematocrit, hemoglobin, white blood count, red blood count, or platelet count (p > 0.01). The inexpensive WPP oxygenator combination function as a disposable heart-lung machine.

Animals↗
PubMedDate not supplied

Physiology of wound healing and surgical wound care.

Wound healing is a systemic process, which occurs stepwise and involves the stages of hemostasis, inflammation, and repair. Hemostasis with fibrin formation creates a protective wound scab. The scab provides a surface beneath which cell migration and movement of the wound edges can occur. Inflammation brings nutrients to the area of the wound, removes debris and bacteria, and provides chemical stimuli for wound repair. Repair begins immediately after wounding and proceeds rapidly through the processes of epithelialization, fibroplasia, and capillary proliferation into the healing area. Different tissues have their own normal rates of growth during the process of healing. The optimal rate of healing is approached when factors advantageous to healing are present and factors having the ability to disturb or retard the healing processes are controlled or absent. These factors are discussed.

Bandages↗
PubMedDate not supplied

Thrombogenic influence of biomaterials in patients with the Omni series heart valve: pyrolytic carbon versus titanium.

An opportunity to assess the thromboembolic rates caused by the construction materials on valve replacements is possible with the Omni series of mechanical heart valves. The Omnicarbon and Omniscience valves are identical in form but differ in that the Omnicarbon valve is constructed entirely of pyrolytic carbon, whereas the Omniscience valve uses titanium for its housing, the rest of its structure being pyrolytic carbon. The literature was reviewed and a comparison in similar groups of patients was made between these two model valves for their thromboembolic rates in the mitral and aortic positions. A total of 569 aortic Omnicarbon valves (4,146 patient years [pt yrs.1) had a thromboembolic events (T/E rate) of 0.5% compared with 1.7% for 468 aortic Omniscience (1,552 pt yrs); p < 0.0001. A total of 298 mitral Omnicarbon valves (3,333 pt yrs) had a T/E rate of 1.6% compared with 2.6% for 716 mitral Omniscience valves (2,134 pt yrs), p < 0.001. There was no difference in the anticoagulation management between the two model valves although the Omniscience valve required higher prothrombin or International Normalized Rate maintenance levels, which resulted in higher bleeding rates among patients with Omniscience valves.

Anticoagulants↗
PubMedDate not supplied

Tyrosine-rich crystalloids in pleomorphic adenoma: SEM findings and partial biochemical characterization.

The rare tyrosine-rich crystalloids (TRC) of salivary gland pleomorphic adenoma (PA) give a positive Million reaction indicating the presence of tyrosine. Their varied histochemical reactions, however, suggest a more complex composition. Two cases of TRC were encountered in a series of 144 PA (1.4%). Both were studied with several histochemical stains, and one tumor particularly rich in TRC was further examined with transmission and scanning electron microscopy and subjected to biochemical analysis using fresh-frozen tissue. TEM showed amorphous, electron-dense masses with no discernable internal structure. SEM revealed a geodelike structure of radially arranged, interlocking plates. Amino acid analysis of normal parotid, tumor with TRC, and a similar tumor without TRC indicated a slightly elevated level of tyrosine and arginine in the tumor with TRC. Polyacrylamide gel electrophoresis of tissue dissolved in sodium dodecyl sulfate revealed dense banding corresponding to polypeptides of a relative molecular weight of approximately 17,000 only in the TRC-rich sample. These bands on further analysis contained relatively large amounts of arginine. Tyrosine was present in only small amounts. TRC appear to be small proteins containing some tyrosine but rich in arginine.

Adenoma, Pleomorphic↗