Search PubMed⌕ Search

Biomedical subjects

J C Collins

Publications and source records attributed to J C Collins.

At least 73 records · Page 4Linked to original sources
PubMed1981

Effects of hypothermia, hemodilution, and pump oxygenation on organ water content, blood flow and oxygen delivery, and renal function.

Hypothermia, hemodilution, and the pump-oxygenator each contribute important effects during cardiopulmonary bypass. We studied their separate effects with a 2(3) factorial, completely fixed experimental design in 16 adult male mongrel dogs. Animals undergoing hypothermia were cooled to 25 degrees +/- 1 degree C. In dogs having hemodilution, hematocrit was adjusted to 25 +/- 2%. An analysis of variance was used to determine the effects of hypothermia, hemodilution, and pump oxygenation. The experiments show that hemodilution produces increased water content in tissue and that edema is greatest in heart and gastrointestinal organs. The pump-oxygenator decreased flow to the subendocardium, whereas hemodilution increased subendocardial flow. Both hypothermia and pump oxygenation diminished flow to the outer kidney cortex, and hemodilution augmented flow to this region. Hypothermia and pump oxygenation decreased and hemodilution raised renal free-water clearance. Although none affected glomerular filtration rate, hypothermia increased filtration fraction while hemodilution diminished it. Hypothermia lessened cerebral cortical flow, an effect opposite that of hemodilution. Thus, hemodilution opposes the adverse effect of hypothermia or pump oxygenation on blood flow, oxygen delivery, or renal function. Increased water content in gastrointestinal organs and myocardium accompanies the beneficial vascular and renal effects of hemodilution.

Animals↗
PubMed1981

Comparison of radionuclide and contrast ventriculography for detection and quantitation of regions of myocardial ischemia in dogs.

Radionuclide and contrast ventriculography were evaluated for their ability to estimate myocardial ischemia. In 14 closed-chest, sedated dogs, a small and larger region of ischemia were produced by inflating balloon occluders on the left anterior descending coronary artery. The systemic arterial pressure, atrial-paced heart rate, global ejection fraction by radionuclide and contrast ventriculography, regional wall-motion abnormalities (as the percentage of abnormally contracting segments), and regional myocardial blood flow (using the microsphere technique) were measured during an initial control period, two separate ischemic periods, and a final control period. The regional ischemic weights based on myocardial blood flow ranged from 0 to 38.5 g and were grouped as zero, small (range 0 to less than 10 g, mean 3.40 g), and large regions of ischemia (greater than 10 g, mean 24.8 g). Regional wall-motion abnormalities were sensitive qualitative indicators of ischemia. Receiver operating characteristic analysis showed that both ventriculographic methods were highly sensitive, specific, and accurate for detecting regional ischemia. Contrast ventriculography was slightly superior for detecting small regions less than 4 g, but the methods were equal for regions greater than 4 g. The arterial pressure and heart rate were unchanged during ischemia. For small regions of ischemia, the global ejection fraction did not fall using either the contrast or radionuclide technique, but it fell significantly when large regions were produced. There was a quantitative relationship between the percentage of abnormally contracting segments and the grams of myocardial ischemia (for radionuclide ventriculography, r = 0.65, P = 0.003, and for contrast ventriculography, r = 0.75, P less than 0.001), but for many small regions of ischemia, wall-motion changes were greater than anticipated, suggesting hypofunction of the continguous normal tissue. This study demonstrated that both radionuclide and contrast ventriculography were quite sensitive and specific for detecting measured amounts of regional ischemia. The functional changes resulting from ischemia are quantitatively related to the extent of regional ischemia, small areas resulting in regional wall motion abnormalities, and large areas producing both reduced global ejection fraction and wall motion changes.

Animals↗
PubMed1979

Increased lung lymph transport without heart failure after coronary ligation in sheep.

Pulmonary edema frequently accompanies acute myocardial infarction (MI). We measured pulmonary arterial (PAP), left atrial (LAP), and aortic pressures (AP),lung lymph flow (QL), and clearance of total serum protein and each of eight protein fractions in five anesthetized sheep before and after coronary artery ligation. After a stable base line of 1 h, ligation produced significant increases in LAP, QL, and clearance of total protein and four protein fractions, but no significant changes in PAP, AP, or lymph-to-plasma total protein concentration ratio (CSL/CSP). Variables returned to pre-MI levels within 2 h after occlusion. The ratio of wet to dry lung weight measured 2 h after ligation was within normal limits. Two sheep in which the time course of postligation LAP was duplicated by left atrial balloon inflation showed no change in QL. The QL changes seen cannot be caused by LAP increase alone without substantial decrease in CSL/CSP. Increased QL with high CSL/CSP is typical of increased lung vascular permeability, which is a plausible explanation of our results.

Animals↗
PubMed1979

Scintigraphic characteristics of experimental myocardial infarct extension.

Technetium-99m-stannous pyrophosphate scintiphotos were evaluated for diagnosing and quantitating myocardial infarct (MI) extension in sedated dogs. Infarction and extension were produced by serial left anterior descending coronary artery ligations at 0 and 48 hours. We compared serial scintiphoto data with regional myocardial blood flow (MBF) (microsphere technique) and infarct histopathology. In eight control dogs, the scintigraphic MI area was stable at 24, 48, and 72 hours. In each of 11 dogs undergoing extension, the MI area increased after the 48-hour occlusion, averaging a 48.9% increase (p less than 0.001). Grossly, most extensions were mixtures of confluent necrosis and moderate (patchy) necrosis. MBF to confluent infarct tissue decreased significantly, allowing the documentation of extension by totaling the grams of newly flow-deprived tissue, but patchy infarct tissue had little flow deprivation, making it difficult to quantitate this type of extension accurately by flow criteria alone. Rarely, extension could be diagnosed using conventional histologic criteria. We concluded that the scintiphoto MI area was related quantitatively to infarct weight in both control and extension. However, it was not possible to determine that an increase in the MI scintiphoto area was an accurate predictor of the degree of extension using independent flow or pathologic criteria.

Acute Disease↗
PubMed1978

Antiviral activity of some beta-diketones. 3. Aryl bis(beta-diketones). Antiherpetic activity.

A series of bis(beta-diketones) was synthesized and tested in vitro for antiviral actitity against herpes simplex type 2. Two parameters which were studied in an effort to optimize activity were the nature of the aryl group and the length of the alkyl bridge. One of the more active compounds, 4,4'-[(1,4-phenylenedioxy)bis(6,1-hexanediyl)]-bis[3,5-heptanedione] (6), was evaluated more extensively and found to inhibit the cytopathic effect in tissue culture of herpes simplex virus type 1 as well as type 2. Compound 6 was evaluated in vivo topically against herpes simplex type 1 in experimentally induced skin infections in guinea pigs. A topical treatment with 2% of 6 in a vanishing cream base, administered 24 h postinfection applied five times daily for 4 days, significantly reduced the number and size of herpetic vesicles.

Administration, Topical↗
PubMed1978

Antiviral activity of some beta-diketones. 4. Benzyl diketones. In vitro activity against both RNA and DNA viruses.

The synthesis and in vitro antiviral evaluation of a series of substituted benzyl beta-diketones are described. The introduction of a styryl group onto the phenyl ring enhanced activity against herpesvirus type 2. The 4-methoxystyryl homologue 8 was evaluated extensively in vitro and was found to be effective against both RNA and DNA viruses. Compound 8 was evaluated in the mouse vagina against herpes simplex type 1 and produced a significant increase in survival rate as well as in survival time.

Animals↗
PubMed1977

Antiviral activity of some beta-diketones. 1. Aryl alkyl diketones. In vitro activity against both RNA and DNA viruses.

The discovery that 4-[3-ethyl-6-[(3,4-methylenedioxy)phenyl]-3-hexenyl]-3,5-heptanedione (40) exhibited an in vitro inhibitory effect against equine rhinovirus led to a structure--activity study to establish the criteria for optimum activity. Modification of the bridge included removal of the ethyl group and reduction of the double bond. The heptanedione was replaced with hexanedione and pentanedione with a minimal effect. The effect of replacing the heptanedione with beta-keto esters and monoketones was also investigated. Maintaining the hexamethylene bridge and heptanedione, the methylenedioxy group was replaced with various substitutents. In general, most substituents did not adversely affect activity particularly against equine rhinovirus although there was some variation in activity against herpesvirus. Strongly hydrophilic groups significantly reduced activity. Finally, the effect of varying the length of the alkyl bridge was examined in the 4-hydroxyphenyl series, where peak activity was attained with n = 8.

Antiviral Agents↗
PubMed1977

Antiviral activity of some beta-diketones. 2. Aryloxy alkyl diketones. In vitro activity against both RNA and DNA viruses.

A series of aryloxy alkyl diketones II was synthesized and screened in vitro for antiviral activity. The effect of various substituents on the phenyl ring, as well as the length of the alkyl bridge, was examined to establish the requirements for optimum activity. One of the most active members of the series, 4-[6-(2-chloro-4-methoxy)phenoxy]hexyl-3,5-heptanedione (56), exhibited a high level of activity against both DNA and RNA viruses in both the tissue culture and organ culture screens and was particularly effective against herpesvirus type 1 and 2.

Antiviral Agents↗
PubMed1976

Chronic torsion of the spleen.

Wandering spleen may result from congenital failure of splenic attachments or acquired laxity of attachments due to stretching. The wandering spleen is quite vulnerable to the complication of torsion, which is seen most often as an acute abdominal emergency due to splenic infarction. A more unusual variant is chronic torsion which causes intermittent mild to moderate abdominal pain, gastrointestinal disturbances and, in one case, hypersplenism. A mass has been present in most cases and may be anywhere in the abdomen or pelvis. Splenectomy should be performed for all cases of wandering spleen with or without torsion.

Adolescent↗
PubMed1975

Measurement of deep body temperature from the urine.

1. The relation between urine and rectal temperatures has been studied under a variety of conditions by using the Uritemp bottle, which measures deep body temperature from the urine. 2. This device gives a reliable measurement of deep body temperature and has advantages over both rectal and oral techniques for many clinical applications. 3. The development of a new and more reliable device, the Uritemp meter, is described. Urine is voided through a specially designed and disposable unit, equipped with either a standard mercury-in-glass thermometer or any one of a range of commercially available electronic thermometers. Provision is made to collect a urine sample simultaneously if required.

Adult↗