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Biomedical subjects

D Ramsey

Publications and source records attributed to D Ramsey.

At least 19 recordsLinked to original sources
PubMed2001

Eplerenone suppresses constrictive remodeling and collagen accumulation after angioplasty in porcine coronary arteries.

BACKGROUND: Coronary artery angioplasty triggers healing that causes constrictive remodeling. Because collagen accumulation correlates with constrictive remodeling and aldosterone has been implicated in collagen accumulation, we examined how aldosterone and the mineralocorticoid receptor antagonists spironolactone and eplerenone affect remodeling and collagen in porcine coronary and iliac arteries after angioplasty. METHODS AND RESULTS: Twenty-four pigs were allocated into 4 treatment groups: oral eplerenone (100 mg/d), oral spironolactone (200 mg/d), subcutaneous aldosterone (400 microgram/d), or no treatment. Twenty-eight days after angioplasty of the coronary arteries, eplerenone increased total vessel area by 30% (P<0.05) and luminal area by nearly 60% (P<0.05) compared with the no-treatment group, without affecting neointima size. These effects were accompanied by a 65% reduction in neointimal and medial collagen density (both P<0.05). Spironolactone was less effective, and aldosterone tended to exert opposite effects on coronary artery structure after angioplasty. These effects were not observed in angioplastied iliac arteries. CONCLUSIONS: Eplerenone attenuates constrictive remodeling after coronary artery angioplasty by mechanisms involving reduction in collagen accumulation, which thus appears to be an important contributor to constrictive remodeling of angioplastied coronary arteries.

Aldosterone↗
PubMed2001

Do "conditions contributing to the death" clarify the predictors of infant mortality in Texas?

Predictors of infant mortality are usually based on the underlying causes reported on infant death certificates. Death certificates also contain space for "Other significant conditions contributing to the death but not resulting in the underlying cause." We investigated whether these "contributing conditions" might clarify the predictors of infant death in Texas or interventions that might reduce deaths from the underlying causes. A "multiple cause of death" file converted the underlying causes and contributing conditions associated with each infant death in 1996 into International Classification of Diseases codes. We ranked the major underlying causes, the conditions contributing to those causes, the conditions contributing to all infant deaths, and the effect of combining the underlying causes with contributing conditions to determine the main predictors of infant mortality. We found that extreme immaturity was the most common condition, causing or contributing to 604 of the 2081 deaths in 1996. We conclude that the underlying causes provide a misleading perception of the major predictors of infant death in Texas; combining them with the conditions contributing to those deaths provides a clearer picture. Given the powerful predictive value of preterm birth for infant mortality, the limited current ability to prevent preterm birth, and the cost of its complications, expanded efforts to improve understanding of its causal processes and develop preventive strategies should be top national and state priorities.

Cause of Death↗
PubMed2001

Time course of pulmonary response of rats to inhalation of crystalline silica: histological results and biochemical indices of damage, lipidosis, and fibrosis.

Previous studies have determined that alpha-quartz (crystalline silica) can cause pulmonary inflammation, damage, and fibrosis. However, the temporal relationship between silica inhalation and pulmonary inflammation, damage, and fibrosis has not been fully examined. To address this gap in our knowledge of silica-induced pulmonary fibrosis, a chronic inhalation study using rats was designed. Specifically, rats were exposed to a silica aerosol (15 mg/m3 silica, 6 h/d, 5 d/wk, 116 d), and measurements of pulmonary inflammation, damage, and fibrosis were monitored throughout the study. We report (1) data demonstrating that the silica aerosol generation and exposure system produced a consistent silica aerosol of respirable size particles; (2) the time course of silica deposition in the lung; (3) calculations that demonstrate that the rats were not in pulmonary overload; (4) histopathological data demonstrating time-dependent enhancement of silica-induced alveolitis, epithelial hypertrophy and hyperplasia, alveolar lipoproteinosis, and pulmonary fibrosis in the absence of overload; and (5) biochemical data documenting the development of lipidosis, lung damage, and fibrosis.

Administration, Inhalation↗
PubMed2000

Response to balloon injury is vascular bed specific: a consequence of de novo vessel structure?

Relative contributions of remodelling and neointimal hyperplasia to restenosis after coronary angioplasty have been inferred from studies using iliofemoral arteries, despite differences in structure/function and smooth muscle cell lineage. We compared the response to balloon overstretch injury of coronary arteries (C, n = 16) and similar sized branches of the iliac arteries (I, n = 18) using preinjury vessel diameter (P). inflated balloon size in vivo (B) and the manufacturer predicted inflated size (M) to examine arterial compliance, as well as resulting injury and morphology in perfusion fixed vessels. Despite similar degrees of oversizing (M/P) in the coronary and iliac arteries (C, 1.44 +/- 0.04; I, 1.51 +/- 0.02), the compliance to overstretch (B-P/M-P) was significantly greater in the coronary than the iliac arteries (C, 0.71 +/- 0.05; I, 0.51 +/- 0.03) (P <0.05) and was associated with a higher injury score (C, 1.64 +/- 0.31; I, 0.39 +/- 0.18 P < 0.05)--only 5/18 iliac vessels had rupture of the IEL compared with 13/16 in the coronary bed. In a subgroup of animals whose vessels (C:n = 7; I:n = 8) were perfusion fixed 28 days after injury, coronary arteries had greater intimal area (C:1.03 +/- 0.42; I:0.10 +/- 0.03 mm2, P < 0.05) but larger luminal area (C:1.61 +/- 0.71; 1:0.76 +/- 0.51, P < 0.05) due to greater area within EEL (C:3.38 +/- 0.49;1:] .49 +/- 0.54, P < 0.05) or less inward remodelling. The injuries resulting from similar strategies of balloon overstretch in the coronary and the iliac arteries are different and affect healing responses--iliac arteries remodel more while coronary arteries develop more intimal hyperplasia. These results indicate that caution is warranted when extrapolating results from the iliac to the coronary artery when investigating restenosis after angioplasty.

Angiography↗
PubMed1999

Greater stroke rate during hospitalization for acute heart disease among Mexican Americans than non-Hispanic whites.

BACKGROUND AND PURPOSE: This study compared the risk for stroke during acute myocardial infarction (AMI), percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) between Mexican Americans (MAs) and non-Hispanic whites. METHODS: We examined the age-specific rate ratios (RR) of acute stroke during hospitalization for AMI, CABG and PTCA in a population-based study in Corpus Christi, Tex. by searching the cardiac surveillance data for ICD-9 codes for stroke (430-437). ICD-9 stroke codes were validated by comparing medical chart abstraction with ICD-9 discharge diagnoses. RESULTS: Stroke codes were found in 220 of the 5,697 admissions for AMI, CABG and PTCA. In the 45- to 59-year age-group MAs had a RR of 2.66 (95% CI 1.36-5.23) relative to non-Hispanic whites. In the 60- to 74-year age-group the RR was 1.52 (95% CI 1.11-2.08). There were no significant differences in the 25- to 44-year age-group. These ethnic relationships were found in nondiabetics but not in diabetics. Women in the 45- to 59-year age-group had a RR of 1.88 (95% CI 1.09-3.25) compared with men, but there were no significant sex differences in the 25- to 44- or 59- to 74-year age-groups. Stroke ICD-9 codes have a poor positive predictive value for acute stroke ranging from 10 to 76%. The stroke misclassifications were nondifferential with respect to ethnicity or sex. CONCLUSIONS: MAs have a higher stroke rate complicating acute heart disease in Corpus Christi. A rigorous stroke surveillance project is needed to study the burden of stroke in MAs, the United States' largest Hispanic population.

Adult↗
PubMed1998

Comparison of reported symptoms of acute myocardial infarction in Mexican Americans versus non-Hispanic whites (the Corpus Christi Heart Project).

This study examines whether there are differences between Mexican Americans and non-Hispanic whites in reported symptoms of acute myocardial infarction (AMI). The symptoms experienced by patients identified in a community-based surveillance program were examined to determine whether between-group differences existed by ethnicity, gender, and diabetic status. Data were available regarding the symptoms of 589 patients, between the ages of 25 and 74 years, who were hospitalized and diagnosed as either having definite or possible AMI in special care units at 1 of 7 hospitals in Corpus Christi, Texas. The most frequently reported symptoms were chest pain (83.2%), chest pressure or discomfort (67.6%), sweating (64.2%), fatigue (62.6%), dyspnea (60.3%), and arm or jaw pain (58.2%). After adjusting for age, diabetes mellitus, and gender, and relative to non-Hispanic whites, Mexican Americans were more likely to report chest pain, upper back pain, and palpitations, and less likely to report arm or jaw pain. Likewise, relative to men, women were more likely to report fatigue, dyspnea, dizziness, upper back pain, palpitations, and cough, and were less likely to report chest pain. Significant differences were also observed when older patients' symptoms were compared with younger patients' symptoms.

Adult↗
PubMed1997

Local anesthesia for infrainguinal arterial reconstruction.

PURPOSE: Perioperative cardiac complications occur in 4% to 6% of patients undergoing infrainguinal revascularization under general, spinal, or epidural anesthesia. The risk may be even greater in patients whose cardiac disease cannot be fully evaluated or treated before urgent limb salvage operations. Prompted by these considerations, we investigated the feasibility and results of using local anesthesia in these high-risk patients. METHODS: From January 1, 1994, through August 30, 1996, 86 infrainguinal reconstructions were performed under local infiltration anesthesia (0.5% or 1.0% lidocaine). Supplementary intravenous sedation with propofol or other agents was given as needed for patients comfort. Most patients had arterial lines but Swan Ganz catheters were used infrequently. Postoperatively, continuous electrocardiographic monitoring was continued in the intermediate or intensive care units. Patients ranged in age from 37 to 86 years (mean 68 +/- 12); 47% were diabetic, 69% had severe coronary artery disease, and 14% had end-stage renal disease. RESULTS: Operations included 7 femoral-femoral, 21 femoral-popliteal, 16 femoral-tibial and 13 popliteal-tibial bypass grafts, 9 pseudoaneurysms, and 20 distal graft revisions (+/- thrombectomy). Autogenous vein was used in eight of the femoral-popliteal and all of the femoral-tibial and popliteal-tibial bypass grafts. There were two postoperative deaths. One patient died of a stroke (1.2%) on postoperative day (POD) 2 and one died on POD 27 of unknown cause. Two other (2%) patients had nonfatal subendocardial myocardial infarctions. Conversion to general anesthesia was required in four (5%) operations, three because patients became agitated and one because a long segment of vein had to be harvested from the opposite leg. Otherwise, patients tolerated the procedures well and postanesthetic recovery problems were minimized. CONCLUSIONS: Limb salvage operations can be done under local anesthesia with acceptable complication rates. In selected patients with high-risk coronary artery disease, local anesthesia has theoretic and practical advantages and should be considered an alternative to general or regional anesthesia.

Adult↗
PubMed1996

Malignant rhabdoid tumor of brain: an aggressive clinical entity.

OBJECTIVE: We report three patients with malignant rhabdoid tumor (MRT) of the brain, two children and an adult. There were three purposes to this report: to describe the clinical course in an adult with MRT; to describe the interesting histopathological metamorphosis of one of the tumors; and to report the outcome of the treatment regimens we used in order to help guide future treatment. Since these tumors are quite rare it is important to continue to try new regimens in the search for effective therapy rather than to repeat ineffective ones. METHOD: Report of three patients. RESULTS: The clinical course in all three patients was typical of these aggressive neoplasms in that chemotherapy and radiotherapy were ineffective in modifying the rapid deterioration leading to death. CONCLUSIONS: MRT can occur in adults. Autopsy in one patient showed that the tumor seemed to undergo an evolution in appearance when compared with the original pathology specimen from craniotomy. Administration of systemic therapy should be prompt and include intrathecal chemotherapy.

Adult↗
PubMed1996

An assessment of the validity of ICD Code 410 to identify hospital admissions for myocardial infarction: The Corpus Christi Heart Project.

BACKGROUND: The identification of myocardial infarction (MI) is typically based on finding events designated by a nosologist with the appropriate International Classification of Diseases (ICD) code, currently code 410. These codes are applied based on review of medical records or death certificates. However, other factors, including reimbursement considerations, may influence the coding process, especially for hospitalizations. Thus, the validity of using ICD code 410 to identify MI must be assessed. METHODS: The Corpus Christi Heart Project (CCHP) is a population-based surveillance programme for hospitalized MI. Patients were identified using concurrent ascertainment in coronary care units and retrospective review of medical records. Events were validated as definite or possible MI using data regarding chest pain, electrocardiographic changes and cardiac enzymes. The validity of using ICD code 410 to identify cases of MI was assessed by calculating the sensitivity, specificity, predictive values and efficiency of ICD code 410 versus the CCHP 'gold standard'. RESULTS: Use of ICD code 410 identified 80.9% (401/496) of definite MI, but only 19.0% (243/1280) of possible MI. Only 12.3% (90/734) of discharges with an ICD 410 code received a 'no MI' designation based on the 'gold standard'. The efficiency of ICD code 410 for identifying MI was 92.0% for definite MI and 77.1% for definite and possible MI. CONCLUSIONS: The use of ICD code 410 to identify hospitalized cases of MI results in a modestly biased overestimate of the number of definite MI hospitalizations; however, this approach warrants consideration due to the expense of validation procedures.

Adult↗
PubMed1989

Clinical periodontal status of regularly attending patients in general dental practices.

Periodontal status of regular patients of general practitioners in the United States is unknown. A project assessing the effectiveness of continuing professional education in altering provider behavior and patient periodontal health provided the opportunity to clinically examine 1092 patients in the offices of 36 general practitioners. These regularly attending patients were selected by a random start systematic sample of patient records. The examination included recording missing teeth and assessing plaque, gingivitis, calculus, probing depth, and attachment loss on the facial and facial-mesial surfaces of the Ramfjord teeth (PDI). The mean patient age was 48 years, and 63% were female. The mean number of missing teeth, not including third molars, was 3.9. Almost 78% of the patients had no sites with a P1I score greater than 1, but 52% of the patients had at least one site with bleeding. Calculus was present in 62% of the patients. Deepest pocket depth was 4 mm or greater in 9% of patients and 3.8% had sites with 4 mm or greater attachment loss. Mean attachment loss was 1.6 mm across all sites. Although the majority of these regular patients had plaque, calculus, and gingivitis, only a minority exhibited periodontitis at the index sites.

Adult↗
PubMed1988

Presence of periodontal data in patient records of general practitioners.

It has been reported that little diagnostic information concerning periodontal conditions is entered in patient records of general practitioners, but actual rates for such chart entries are unknown. Records of regular patients, seen at least annually, were randomly selected from the offices of 36 general practitioners in two North Carolina counties. In each office 80 records were selected for audit. After adjustment, the final sample consisted of 2488 audited records. Entries noting the presence or absence of 14 diagnostic conditions were identified for the five previous years and for the patient's most recent examination. The presence of a periodontal diagnosis or periodontal treatment plan was noted. The number of radiographic sets exposed in the previous five years and the age of the most recent set were determined for complete series/panoramic films and for bitewings. Across practices, the most frequent notations (20.5% within the past five years) concerned the presence of probing depths and calculus. Gingival bleeding (13%) and plaque (12%) were noted less frequently. A periodontal diagnosis was recorded in only 16.3% of the records. Annualized rates for radiographic sets were 0.09 for complete series/panoramic films and 0.50 for bitewings. These data suggest that, except for radiographs, the majority of patient records do not contain sufficient diagnostic information to describe patients' periodontal health.

Adult↗
PubMed1985

Community coverage in a rural, church-based, hypertension screening program in Edgecombe County, North Carolina.

In a rural, church-based hypertension program in Edgecombe County, North Carolina, screening of the congregations was complemented by a community outreach component targeted at 18-60 year old males, a group at higher risk for untreated hypertension. Compared with its estimated frequency in the community, untreated hypertension was as common in the church congregations and somewhat less prevalent than expected among outreach screenees.

Adolescent↗