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Biomedical subjects

S M Scott

Publications and source records attributed to S M Scott.

At least 19 recordsLinked to original sources
PubMed1991

Effects of subchronic amphetamine or amfonelic acid on rat brain dopaminergic and serotonergic function.

Repeated doses of direct or indirect CNS stimulants are known to cause behavioral hypersensitivity. The biochemical basis for hypersensitization remains unclear. Since the dopaminergic system uses a large storage pool that is only slowly mobilized to releasable sites, a change in this relationship may underlie the biochemical changes leading to increased responsiveness to stimulants. To test this hypothesis, rats were first tested with low doses of 2.5 mg/kg amphetamine or 1.0 mg/kg amfonelic acid (AFA) for their locomotor response, then 5.0 mg/kg amphetamine or 2.5 mg/kg AFA were injected daily for 7 days and the rats retested with the lower doses of amphetamine or AFA, respectively. Both drugs produced hypersensitivity, but the cataleptic response to acute dopamine (DA) receptor blockade by haloperidol was unaltered. The ability of haloperidol to increase DA metabolism was unaltered and the ability of acute AFA to synergize with haloperidol was similar in the striatum of stimulant and saline treated rats, but reduced in the medial prefrontal cortex of both AFA and d-amphetamine treated rats. Additional rats had DA2 receptor sensitivity measured in the striatum and frontal cortex, but no significant differences were found. Only amphetamine caused a significant decrease in frontal cortex serotonin type 2 receptors. Since there was no alteration in the ability of AFA to increase neurogenic release of DA in the striatum and a decrease occurred in prefrontal cortex, an increase in the storage to functional pool exchange in the nigrostriatal and mesocortical DA containing neurons seems unlikely. In contrast, both the amphetamine and AFA treatment groups had their brain 5HT and 5HIAA levels reduced by about 50%. This suggests that changes in other transmitter systems may have a permissive effect allowing exaggerated responses to excessive DA release.

Amphetamine↗
PubMed1991

Intraoperative management of severe endobronchial hemorrhage.

Endobronchial hemorrhage due to pulmonary artery perforation by a Swan-Ganz catheter developed during coronary artery bypass grafting while weaning from cardiopulmonary bypass. After reinstitution of cardio-pulmonary bypass with pulmonary artery venting, bleeding was localized to the right lower lobe bronchus using fiberoptic bronchoscopy. A Fogarty embolectomy catheter was inflated in the bronchus to tamponade successfully only the right lower lobe. This case illustrates a method of distal bronchial blockade for maximal retention of pulmonary function and avoidance of pulmonary resection.

Blood Loss, Surgical↗
PubMed1991

Quality of life after bypass surgery for unstable angina. 5-year follow-up results of a Veterans Affairs Cooperative Study.

To assess the effect of bypass surgery on outcome from unstable angina, 468 patients were randomized to medical treatment (237 patients) or surgery plus medical treatment (231 patients) and have been followed for comparison of survival, cardiac end points, and quality of life; the latter end point is discussed in the present report. Data were available at 3 and 5 years for 80% and 82% of patients in the medical group, respectively, and 77% and 80% of patients in the surgery group, respectively. At 3 months after randomization to therapy, 79.8% of patients in the surgery group reported subjective improvement, compared with 58% of the medical group, 12.6% of the surgery group reported no change compared with 24.5% of the medical group, and 5.5% of the surgery group reported worsening compared with 24.5% of the medical group (p less than 0.01 by chi 2). Similar data were found for chest pain status, and the benefit to the surgery group remained statistically significant through 5 years of follow-up. Crossover rate to surgery was 43% by 5 years. Treadmill duration was increased in the surgery group compared with the medical group (6.5 +/- 0.25 versus 5.3 +/- 0.25 minutes at 6 months, p less than 0.01), and a significant difference was again demonstrated at 3 and 5 years. A trend toward decreased recurrence of unstable angina was present in the surgery group at 1 year (six of 168 [3.6%] versus 13 of 187 [6.9%] in the medical group, p = 0.158), but the two groups were similar at 3 and 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina, Unstable↗
PubMed1991

Developmental pattern of urinary epidermal growth factor in the premature infant and the influence of gender.

We report the cross-sectional pattern of first day urinary epidermal growth factor/creatinine (EGF/Cr) levels in 159 appropriate for gestational age infants born at 26-41 weeks gestation. EGF/Cr levels rose significantly earlier in female infants than levels in male infants. In female infants levels were similar to term levels beginning at 30-32 weeks. Mean EGF/Cr levels in male infants were similar to term values beginning at 32-34 weeks. We could not demonstrate any influence from acute perinatal events on EGF/Cr levels. In a subset of 28 infants, a weekly longitudinal study of urinary EGF/Cr levels was undertaken. The urinary EGF/Cr pattern correlated significantly with both corrected gestational and postnatal ages. A significant change in the EGF/Cr pattern was observed at a corrected gestational age of 32 weeks and at 4 weeks postnatal age. There was no significant difference in EGF/Cr levels between males and females. Our results demonstrated a significant difference in first day urinary EGF/Cr levels between female and male preterm infants during the early third trimester. This difference was seen at a time in gestation when other gender-specific maturational and growth differences are noted. When infants born at less than 32 weeks gestational age were followed longitudinally, the urinary EGF/Cr pattern, when expressed by corrected gestational age, was significantly modified from that in the cross-sectional study.

Creatinine↗
PubMed1991

Coronary bypass surgery improves survival in high-risk unstable angina. Results of a Veterans Administration Cooperative study with an 8-year follow-up. Veterans Administration Unstable Angina Cooperative Study Group.

To identify high-risk subgroups, 468 patients with unstable angina were prospectively stratified according to the clinical presentation of unstable angina (type I or type II) and left ventricular function (normal or abnormal) and were randomized to conventional medical therapy or surgical treatment with coronary bypass surgery. Type I patients (n = 374) were those who had progressive effort angina or recent angina at rest. Type II patients (n = 94) were those who had severe rest angina associated with ST-T changes on the electrocardiogram. Follow-up for 8 years showed that the cumulative mortality rates for type II patients with abnormal left ventricular function were significantly lower in the surgical patients compared with the medical cohorts (13% versus 46%, p less than 0.04). In the other subgroups, cumulative medical and surgical mortality rates were not different. Thus, type II patients with abnormal left ventricular function appear to be the subgroup of patients who are at the highest risk with medical therapy. Coronary bypass surgery significantly reduces the mortality in this high-risk subgroup of patients with unstable angina.

Angina, Unstable↗
PubMed1991

Experience of an interdisciplinary pediatric pain service.

This article is a report of our experience with an interdisciplinary pain service in a large tertiary care pediatric hospital. During the first 2 years of operation, we received 869 consultations and referrals from more than 19 hospital divisions. Postoperative pain was the most frequent reason for consultation (56% of patients). Patients with pain related to cancer and sickle cell disease comprised 25% of the consultations. The remaining patients had a wide variety of primary diagnoses and causes of pain. We calculated the time spent by pain service physicians in direct patient care. The majority (63%) of physician time was spent with a small number of patients (17%). Most of these patients had pain that was unrelated to surgery, cancer, or sickle cell disease, and many posed dilemmas in diagnosis and treatment. Physician time was correlated directly to the use of psychologic and physical therapies for the pain, involving multiple team members. This experience supports the demand for an interdisciplinary pain service in a tertiary care children's hospital. A significant amount of physician time is necessary to provide patient care and to maintain a team approach, however, and pediatricians and other health care professionals who aim to implement such services should be cognizant of the time required.

Child↗
PubMed1991

The present attitude toward the biology and technology of limb lengthening.

Over the past ten years, many technical innovations and biologic concepts have appeared as they relate to the lengthening of long bones. Each of these has had a substantial influence upon the approach to the treatment of major discrepancies in limb length and angular deformities. It is the purpose of this paper to present these issues as objectively as possible so that the reader can put them into proper perspective, recognizing that there will be some degree of bias in the implementation of some of the technical devices. To appreciate the utility of these techniques, it is necessary to understand the biologic foundation of each method as well as its advantages and disadvantages.

Bone Lengthening↗
PubMed1991

Effect of necrotizing enterocolitis on urinary epidermal growth factor levels.

The pattern of urinary epidermal growth factor/creatinine levels in necrotizing enterocolitis was examined in 75 infants (in 28 infants the diagnosis of necrotizing enterocolitis was considered; 47 infants were studied for effect of surgery or nutrition on epidermal growth factor levels). There was a consistent and significant increase in epidermal growth factor/creatinine values at the time of diagnosis of necrotizing enterocolitis compared with baseline values. Epidermal growth factor levels in infants without necrotizing enterocolitis and in early nutrition remained unchanged. These results suggested that urinary epidermal growth factor/creatinine levels may differentiate stage II and III necrotizing enterocolitis from stage I disease. The increased epidermal growth factor/creatinine levels may be related to the absorption into the circulation of preexisting gastrointestinal tract epidermal growth factor through damaged tissue or to increased synthesis by the gastrointestinal tract in response to the injury caused by necrotizing enterocolitis.

Creatinine↗
PubMed1989

Soft tissue fibrosarcoma. A clinicopathologic study of 132 cases.

Over the last 20 to 30 years, a recognition and general acceptance of the entity of malignant fibrous histiocytoma and monophasic synovial sarcoma has occurred. The introduction of these diagnostic categories among the generic group of spindle cell sarcomas now requires a reevaluation of the more traditional and historic entity of fibrosarcoma and the clinical ramification of this diagnosis. A review of 132 cases of fibrosarcoma using current diagnostic criteria was undertaken to clarify the behavior of fibrosarcoma as diagnosed in current patients. Special attempts were made to correlate histologic grade and Enneking stage in fibrosarcomas in an effort to correlate their predictive value in metastatic rate and survival.

Actuarial Analysis↗
PubMed1989

Effects of classical and atypical antipsychotic drugs on isolation-induced aggression in male mice.

A series of classical, atypical and putative antipsychotic drugs were compared for their ability to inhibit isolation-induced intraspecies aggression with affinity for D-2 dopamine receptors and induction of akinesia. The majority of drugs tested significantly inhibited aggressive behavior only after doses that greatly decreased the ability of mice to move. Even though akinesia seemed to account for inhibition of aggression there was no apparent correlation with binding to striatal D-2 receptors.

Aggression↗
PubMed1989

"Benign" metastasizing giant cell tumor: evaluation of nuclear DNA patterns by flow cytometry.

Nuclear deoxyribonucleic acid (DNA) ploidy was determined by flow cytometry for nine histologically benign giant cell tumors that developed systemic metastases and for eight tumors that did not metastasize. Specimens from the primary tumor, local recurrences, and pulmonary metastases were evaluated. No feature of the DNA ploidy pattern was identified to distinguish giant cell tumors that metastasized from those that did not. The mean percentage of diploid (G0/G1 peak, 2C) cells was 81% in the metastasizing group and 80% in the nonmetastasizing group. The DNA ploidy pattern of the primary tumors was not different from that of their metastases. No DNA aneuploid patterns were observed among the benign tumors.

Cell Nucleus↗
PubMed1989

Immunoreactive human epidermal growth factor concentrations in amniotic fluid, umbilical artery and vein serum, and placenta in full-term and preterm infants.

Immunoreactive human epidermal growth factor (IR-hEGF) was measured in samples taken from 27 full-term and 14 preterm infants. The samples included amniotic fluid, amniotic membranes, fetal and maternal sides of the placenta, and matched umbilical artery and umbilical vein serum. Our results demonstrated the presence of IR-hEGF in the human placenta, amniotic fluid and cord blood during the second half of gestation. The increase in placental tissue, amniotic fluid, and cord blood concentration with progressive gestation suggests a possible functional role for EGF during perinatal development.

Amniotic Fluid↗
PubMed1989

Medical compared with surgical management of unstable angina. 5-year mortality and morbidity in the Veterans Administration Study.

We evaluated medical in comparison to surgical plus medical (surgical) treatment of unstable angina using a prospective randomized protocol that stratified patients by clinical presentation and by invasive evaluation of left ventricular (LV) function. Clinical presentations were as follows--type 1: progressive or new onset angina relieved by medication; type 2: prolonged bouts of angina poorly or incompletely relieved by medication. Abnormal LV function was arbitrarily defined as ejection fraction less than 0.50 or LV end-diastolic pressure 16 mm Hg or more. Of 468 patients, 237 were assigned to medical and 231 to surgical therapy. There were 374 type 1 and 94 type 2 patients. LV function was normal in 334 and abnormal in 134 patients. Compared with results at 24 months, this 60-month follow-up study showed important differences in survival for patients with three-vessel disease: 75% for medical and 89% for surgical patients (p less than 0.02). The cumulative 5-year rate of repeat hospitalizations for cardiac reasons was less with surgical patients for either clinical presentation. For type 1, medical patients had a 56% rate, and surgical patients had a 42% rate (p = 0.004). For type 2, medical patients had a 62% rate, and surgical patients had a 43% rate (p = 0.05). Overall mortality did not differ between the two treatments, and this remained true in type 1 versus type 2 patients and in those with normal versus abnormal LV function. However, regression analysis of medical and surgical groups with ejection fraction as a continuous variable showed that mortality of medical patients depended on ejection fraction (p = 0.004), whereas the mortality of surgical patients did not (p = 0.76), and survival in the surgical group was higher in the lowest ejection fraction tercile-73% for medical and 86% for surgical patients, p = 0.03. We conclude that surgery improves survival in patients with three-vessel disease and leads to fewer subsequent hospitalizations for cardiac reasons. An impaired ejection fraction had an adverse impact on survival of medical patients but not on surgical patients, and mortality in surgical patients was improved compared with medical patients in the lowest ejection fraction tercile.

Angina Pectoris↗