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Biomedical subjects

R F Scott

Publications and source records attributed to R F Scott.

At least 37 records · Page 2Linked to original sources
PubMed1987

Ultrasound of the empty gestation sac in threatened abortion.

The major concern when an empty gestation sac is encountered during threatened abortion is whether or not the pregnancy is viable. Viable pregnancies are managed expectantly, whereas non-viable pregnancies are treated by evacuation of the uterus. Early evacuation of the non-viable pregnancy spares the patient considerable anxiety and discomfort. This study shows that a single ultrasound examination is useful in differentiating viable from non-viable empty gestation sacs. The size of the empty gestation sac was found to be the most useful criterion for determining non-viability. Empty gestation sacs with sizes greater than 26 mm were non-viable, a specificity of 100%, accounting for 43% (42 out of 102) of patients in our series. Other ultrasound criteria found to be useful were shape, position, wall and decidual reaction. The positive predictive value for a successful outcome to a pregnancy was low, being only 41% (9 out of 22).

Abortion, Threatened↗
PubMed1987

A double-blind comparison of nalbuphine and meperidine hydrochloride as intravenous analgesics in combination with diazepam for oral surgery outpatients.

This study compared the analgesic efficacy, sedative, and amnesic properties, and side effects of nalbuphine versus meperidine as intravenous premedicants in combination with intravenous diazepam for the treatment of outpatients undergoing the removal of impacted third molars with alveolar nerve block anesthesia. Forty patients were evaluated in this double-blind crossover study. Nalbuphine was shown to have analgesic, sedative, and amnesic properties similar to meperidine. Nalbuphine, when compared to meperidine, produced significantly lower intraoperative systolic and diastolic blood pressures. Because of this cardiovascular stability, nalbuphine should be considered over meperidine for use in the cardiovascularly compromised patient undergoing oral surgery.

Adolescent↗
PubMed1986

Atherosclerotic lesions in coronary arteries of hyperlipidemic swine. Part 2. Endothelial cell kinetics and leukocyte adherence associated with early lesions.

The role of endothelial cells (EC) in the development and progression of early swine intimal cell mass (ICM)-derived coronary artery lesions in 55 swine fed either a mash or hyperlipidemic diet for 14, 49 or 90 days was investigated. Characteristics studied were endothelial cell turnover (using tritiated thymidine autoradiography), adhesion of leukocytes (presumably chiefly monocytes) to endothelium, and the presence or absence of endothelial cell denudation. The major findings were: An increased adherence of leucocytes to endothelial cells over ICM-lesions in the HL-90 day group compared to the corresponding mash value at 90 days as well as to that of each of the other HL and mash groups. Significant positive correlation between the labeling indices (LI) of endothelial cells lying over coronary artery lesion cells and the labeling indices of the underlying ICM-lesion cells; also, a significant positive correlation between the labeling indices of endothelial cells over lesions of the abdominal aorta and those of the coronary arteries. At 90 days the endothelial cell LI over lesions in the HL group was significantly higher than the corresponding values in the mash group. Since the EC increase rates by growth in the two groups are also significantly different, the differences in LIs reflect at least in part EC growth differences and no strong conclusion can be made regarding possible cell turnover differences. No frank endothelial denudation was found. The findings suggest that in swine coronary arteries participation by monocytes from circulating blood is a factor in the early progression of the lesion as well as smooth muscle cell proliferation.

Animals↗
PubMed1986

Intimal cell mass-derived atherosclerotic lesions in the abdominal aorta of hyperlipidemic swine. Part 2. Investigation of endothelial cell changes and leukocyte adherence associated with early smooth muscle cell proliferative activity.

We have investigated several aspects of endothelial cell (EC) behavior during the initiation and early development of intimal cell mass (ICM)-derived atherosclerotic lesions in the distal abdominal aortas of young swine fed hyperlipidemic (HL) diets for 0, 14, 49, or 90 days. By scanning electron microscopy no breaks in endothelial integrity or other abnormalities were observed even at 90 days on diet after lesions were well established. Also, counts of leukocytes adherent to the endothelium by both scanning and light microscopy revealed no greater numbers in HL than in mash control swine. Estimates of individual EC losses over ICM-lesions in the HL swine (based on calculations from tritiated thymidine labeling indices and EC growth rates determined by counts) suggested a loss of approximately one per 100 EC/day. This loss over ICM lesion was not significantly greater than that over ICM in mash controls, but was significantly greater than that of EC not over ICM lesions in the same HL animal. In any event, the estimated loss seems to be too trivial for the endothelial barrier to be compromised even transiently in a biologically significant fashion. A significant correlation was observed between tritiated thymidine labeling indices of cells within the ICM lesions and of those of the overlying EC that was not observed with the ICM in the controls. Possibly the positive correlation may be a result of the abluminal surface of the overlying EC being exposed to the abnormal milieu of the ICM lesion. It is emphasized that results reported here apply only to ICM-derived lesions at an early stage of development and that they do not contradict results obtained by others with other lesion types such as those derived from monocytes. Furthermore, in later stages of development of ICM-derived lesions in the same model we know that extensive endothelial cell damage can be demonstrated. Also, functional changes in endothelial permeability may have been present in early stages that would not have been detected with the methods used in this study.

Animals↗
PubMed1986

Indications for ultrasound in the evaluation of the pathological scrotum.

Scrotal ultrasound scans carried out on 156 patients were reviewed in a retrospective study and the sonographic findings and indications evaluated. Ultrasound was able accurately to distinguish the normal from the pathological scrotum. Extratesticular lesions were readily differentiated from testicular lesions. Abnormal testicular echo patterns were usually associated with tumours, but orchitis, granulomas and haematomas were found to have a similar appearance. Occult testicular tumours could readily be identified. Ultrasound was also useful in excluding underlying pathology in hydroceles, in the diagnosis and follow-up of epididymitis and other epididymal lesions and in the assessment of underlying testicular damage in traumatic haematoceles. Ultrasound may also be useful in post-orchiectomy follow-up examinations to exclude tumour in the contralateral testis.

Cysts↗
PubMed1985

Endothelial cell labeling indices in swine aortas in relation to intimal cell mass-derived atherosclerotic lesions.

In the swine abdominal aorta, most atherosclerotic lesions arise from naturally occurring collections of intimal cells called intimal cell masses. The main objective of this study was to determine if the tritiated thymidine labeling index of endothelial cells lying over intimal cell masses was greater than that of endothelial cells not over intimal cell masses. A higher endothelial cell labeling index over intimal cell masses would indicate possibly a greater turnover in the area. Such a finding would suggest possible transient but repeated breaks in the endothelial cell barrier that might contribute to the initiation of the atherosclerotic lesion in intimal cell masses. In 2 groups of mash-fed swine, 2 and 11 months old, no differences were found in labeling indices of endothelial cells lying over or not over intimal cell masses. It appears that the initiation of atherosclerosis in swine abdominal aorta is not dependent upon pre-existing altered endothelial cell kinetics as measured by tritiated thymidine labeling indices. The labeling index of cells within the intimal cell mass was significantly higher than in the media; this also is obviously not dependent upon an increased labeling index of the covering endothelial cells. Another group of swine were killed at 11 months of age after receiving a hyperlipidemic diet for 270 days. The labeling index of endothelial cells over atherosclerotic lesions was significantly higher than the labeling index of endothelial cells not over lesions in these swine, and also significantly higher than that of endothelial cells over intimal cell masses in the 11-month old mash-fed group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1985

Adverse effects of suxamethonium. Failure of prevention by atracurium or fazadinium.

One hundred patients were allocated randomly to pretreatment with atracurium 2.5 mg, atracurium 5 mg, fazadinium 3.75 mg or saline 3 minutes before the injection of suxamethonium. The effect upon neuromuscular conduction was studied by recording the mechanical response of the adductor pollicis muscle to indirect stimulation of the ulnar nerve using repeated 2 Hz train of four stimuli. Blood samples were taken at intervals for the measurement of serum potassium. There was no significant difference in the incidence of postoperative muscle pains between the groups in the first 72 hours following anaesthesia. The use of the larger pretreatment dose of atracurium resulted in clinically significant neuromuscular blockade in three of the subjects. Minimal changes in serum potassium occurred in all patients but there was no statistical difference between the groups.

Adolescent↗
PubMed1985

Endothelial and lesion cell growth patterns of early smooth-muscle cell atherosclerotic lesions in swine.

This study shows that the endothelial cell turnover over the early porcine atherosclerotic lesion is more or less uniform in distribution. This is contrary to the findings in White Carneau pigeons where the increased endothelial cell turnover has a zonal pattern, being much greater at the lesion edge. The difference in the endothelial cell pattern of turnover in the two lesions probably is a reflection of their different manner of development. The porcine abdominal aortic lesion is derived from naturally occurring preexisting collections of intimal smooth-muscle cells called intimal cell masses. After 90 days of a hyperlipidemic diet these lesions are composed predominantly of smooth-muscle cells, with very few monocytes. The White Carneau pigeon lesion develops from circulating monocytes that have been shown to adhere to the edge of the lesion.

Animals↗
PubMed1984

Population dynamics of arterial cells. XIV. Evidence for no significant G2 arrest of intimal and medial cells in young nonatherosclerotic swine.

In an earlier study of swine results from analysis of tritiated thymidine data by an "ancestor table" method suggested a substantial arrest of arterial cells in the G2 phase of the cell cycle. A later study with a cytofluorometric method gave contradictory results with no evidence for significant G2 arrest. On reexamination of the earlier data with the ancestor table method in the light of current knowledge, it was found that the fact that nuclei in the S and G2 phases prior to division are larger than those in G1 after division had not been taken into account. The main purpose of the current study was to find out whether the evidence for G2 arrest would entirely disappear if adjustments were made for differences in nuclear sizes before and after division. A baseline group sacrificed 2 hr after tritiated thymidine injection and two experimental groups (one fed hyperlipidemic diet and the other given cholesterol-free mash) sacrificed 47 hr after injection were studied. Using the ancestor table method it was found that virtually all labeled arterial cells divided in both groups; thus there is no evidence for G2 arrest. The data was also analyzed with a form of the "mean grain count halving" method and this also showed all labeled cells dividing.

Animals↗
PubMed1984

Major maxillomandibular malrelations and temporomandibular joint pain-dysfunction.

A retrospective questionnaire survey of 102 patients who underwent orthognathic surgery for maxillomandibular disharmonies assessed the incidence of TMJ pain-dysfunction in both pretreatment and posttreatment phases. While retrospective questionnaire studies have obvious limitations, the following conclusions deserve consideration. The incidence of TMJ pain-dysfunction symptoms found in this patient population appears to be higher than the incidence of those symptoms reported in previous epidemiologic studies of general populations which involved subjective symptoms alone. Maxillomandibular disharmonies may be an important etiologic factor in the development of TMJ pain-dysfunction. Surgical correction of the disharmony in a significant percent of patients with maxillomandibular disharmonies and concomitant TMJ pain-dysfunction may alleviate or improve the TMJ pain-dysfunction symptoms. There is a possibility that patients may develop TMJ pain-dysfunction symptoms after orthognathic surgery.

Female↗
PubMed1982

Evans blue dye: its accumulation in extracellular space in relation to endothelial cell basement membrane in normal an atherosclerotic areas of abdominal aorta.

Intravenously (IV) injected Evans blue dye consistently accumulates at particular areas in aortas of normal swine. Theses areas are also where IV injected tracer cholesterol accumulates. We studied the ultrastructural characteristics of blue vs nonblue areas in the abdominal aortas of both control and atherosclerotic swine. In blue areas, the basement membrane was largely missing beneath the endothelial cells in both normal swine and swine with raised atherosclerotic lesions; the basement membrane that was present was often discontinuous. If the basement membrane helps regulate the transport of Evans blue dye across the arterial wall, its absence may play a part in the accumulation of the dye. In raised atherosclerotic lesions, those portions that accumulated Evans blue dye had a larger amount of amorphous extracellular matrix than did nonblue areas. No consistent difference between blue and nonblue areas were seen in the endothelial cell junctions of abdominal aortas in either control or atherosclerotic swine. Similarly, no differences were demonstrable in the number of Golgi complexes, mitochondria, or profiles of smooth or rough endoplasmic reticulum per cell.

Animals↗
PubMed1980

Evans blue dye. Accumulation in swine aortic intimal cell collections and atherosclerotic lesions.

A two-part study concerned the accumulation of intravenously injected Evans blue dye in the abdominal aorta of swine. In normolipidemic swine weighing up to 90 kg each, Evans blue accumulated predominantly in areas of the aorta that were the site of intimal smooth muscle cell collections. The second part of the study dealt with Evans blue accumulation in swine with advanced atherosclerosis. The extent of blue staining in these animals was not significantly different than in normolipidemic, nonatherosclerotic swine of the same size. The dye showed a predilection for raised atherosclerotic lesions, but only one quarter of the surface of these lesions was stained. Histologic studies of the uppermost portion of blue and nonblue lesion areas showed that the dye preferentially accumulated in regions with lower concentrations of foam cells. Injected isotopic cholesterol tended to accumulate in the blue rather than the nonblue areas.

Animals↗
PubMed1980

Regional coronary perfusion and bioenergetics in experimental atherosclerosis.

The effects of experimental coronary atherosclerosis on myocardial high energy phosphates and regional coronary perfusion and oxygen delivery were studied. Hypercholesterolemic (HC) New Zealand white rabbits developed mild to moderate coronary vascular disease in 4 months when serum cholesterol levels were maintained at 1500--2000 mg/dl. Resting left ventricular levels of creatine phosphate, adenosine triphosphate (ATP), and the cellular energy charge were unaltered after 2 months of diet but were decreased after 4 and 6 months. Tissue lactate and the lactate/pyruvate ratio were increased after 4 months, suggesting mild tissue ischemia. The regional blood flow rate was measured in rabbits given pentobarbital after 6 months of diet using labeled microspheres, and the response to stress was tested after 5 minutes of hypoxic ventilation (5% O2/N2). The percentage of cardiac output to subendocardium (endo) and subepicardium (epi) in HC rabbits and that in control animals were similar at rest, but unlike that of control animals, the endo perfusion did not increase significantly in HC animals during hypoxic stress. Baseline regional left ventricular oxygen deliveries were similar between groups, but the baseline endo/epi oxygen delivery ratio was reduced in HC rabbits. In control rabbits hypoxia did not alter total O2 delivery, and the endo/epi oxygen delivery ratio was constant, whereas hypoxia in HC animals produced a decrease in total oxygen delivery and a further decrease in the endo/epi oxygen delivery ratio. Thus, moderate long-term coronary occlusive disease produced alterations in the distribution of coronary perfusion that are similar to those after acute partial occlusion, ie, selective reductions in blood flow and oxygen delivery to subendocardium. These results may relate to the pathogenesis of subendocardial infarction in man, which often occurs in the absence of complete coronary occlusion.

Animals↗