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Biomedical subjects

A K Jacobs

Publications and source records attributed to A K Jacobs.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effect of gender on postoperative outcomes and hospital stays after coronary artery bypass grafting.

BACKGROUND: Compared to men, women undergoing coronary artery bypass grafting appear to have a higher morbidity and mortality, particularly in the perioperative period. This study was designed to answer the questions of whether such differences in clinical outcomes between men and women still exist with improvements in surgical techniques and determine whether it is gender or associated comorbid conditions in women that lead to higher morbidity. METHODS: An analysis of a single center's contemporary experience (1994 to 1997) of 1,743 consecutive patients undergoing primary coronary artery bypass grafting was performed. Only reoperations were excluded. Data were collected prospectively and presented as mean +/- standard deviation (p<0.05). RESULTS: Women represented 30.0% of patients. Compared with men, women were older (68.4 versus 63.8 years; p<0.05), and had more urgent surgical interventions (70.0% versus 56.7%; p<0.05), a higher incidence of diabetes (42.1% versus 26.7%; p<0.05), hypertension (82.0% versus 73.9%; p<0.05), lower body surface area (1.73+/-0.18 m2 versus 2.03+/-0.19 m2; p<0.05), and hematocrit (31.7%+/-3.9% versus 36.2%+/-3.9%; p<0.05). Ejection fraction, incidence of previous myocardial infarction, chronic obstructive pulmonary disease, left main (LM) disease, renal insufficiency, extent of coronary disease, and preoperative intraaortic balloon pump were similar. Women received fewer arterial grafts (91.0% versus 95.5%; p<0.05) and distal anastomoses (3.31+/-0.88 versus 3.49+/-0.94 p<0.05). Despite these differences, there were no statistical differences in the incidence of postoperative death (1.5% versus 1.0%), myocardial infarction (0.6% versus 0.6%), or cerebrovascular accident/transient ischemic attack (1.1% versus 0.4%) between men and women. Women had a higher inotropic support (10.2% versus 4.4%; p<0.05) and longer hospital stays (7.3+/-5.7 days versus 6.3+/-4.2 days; p<0.05). Using multivariate analysis, female gender was not an independent predictor of death or postoperative complications but was a predictor of length of hospital stay, use of arterial grafts, and extent of coronary revascularization. CONCLUSIONS: After accounting for differences in their risk variables, the incidences of death, perioperative myocardial infarction and cerebrovascular accident/ transient ischemic attack after coronary artery bypass grafting in women and men were not statistically significant. Perioperative complications are related to comorbid risk factors but not to female gender itself. Further studies are warranted.

Age Factors↗
PubMed1999

Is a strategy of intended incomplete percutaneous transluminal coronary angioplasty revascularization acceptable in nondiabetic patients who are candidates for coronary artery bypass graft surgery? The Bypass Angioplasty Revascularization Investigation (BARI).

OBJECTIVES: Our objective was to determine whether a strategy of intended incomplete percutaneous transluminal coronary angioplasty revascularization (IR) compromises long-term patient outcome. BACKGROUND: Complete angioplasty revascularization (CR) is often not planned nor attempted in patients with multivessel coronary disease, and the extent to which this influences outcome is unclear. METHODS: Before randomization, in the Bypass Angioplasty Revascularization Investigation, all angiograms were assessed for intended CR or IR via angioplasty. Outcomes were compared among patients with IR intended if assigned to angioplasty, randomized to coronary artery bypass graft surgery (CABG) versus angioplasty; and within angioplasty patients only, among patients with IR versus CR intended. RESULTS: At 5 years, there was a trend for higher overall (88.6% vs. 84.0%) and cardiac survival (94.5% vs. 92.1%) in CABG versus angioplasty patients with IR intended. The excess mortality in angioplasty patients occurred solely in diabetic subjects; overall and cardiac survival were similar among nondiabetic CABG and angioplasty patients. Freedom from myocardial infarction (MI) at 5 years was higher in nondiabetic CABG versus angioplasty patients (92.4% vs. 85.2%, p = 0.02), vet was similar to the rate observed (85%) in nondiabetic CABG and angioplasty patients with CR intended. Five-year rates of death, cardiac death, repeat revascularization and angina were similar in all angioplasty patients with IR versus CR intended. However, a trend for greater freedom from subsequent CABG was seen in CR patients (70.3% vs. 64.0%, p = 0.08). CONCLUSIONS: Intended incomplete angioplasty revascularization in nondiabetic patients with multivessel disease who are candidates for both angioplasty and CABG does not compromise long-term survival; however, subsequent need for CABG may be increased with this strategy. Whether the risk of long-term MI is also increased remains uncertain.

Aged↗
PubMed1999

Peer victimization and attitudes about violence during early adolescence.

Examined roles for attitudes about violence as a possible influence on the frequency of commonplace aggression toward peers among 1,033 adolescents in the 7th through 9th grades. The peer victimization measure adapted from prior studies yielded 2 reliable subscales: Victimization of Self and Victimization of Others. The attitudes and beliefs measure modified for this study yielded 3 reliable subscales (Aggression Is Legitimate and Warranted, Aggression Enhances Power and Esteem, One Should Not Intervene in Fights). These attitudes were meaningfully related to self-reported aggression toward peers but less clearly related to self-victimization. The attitudes were plausible mediators of the relation between gender and aggression toward others and appeared influential for both boys' and girls' aggression toward peers. Little support was found for these attitudes moderating the relation between self-victimization and aggression toward others, yet a clear link between victimization of self and aggression toward others was evident. Results support an emphasis on attitudes and values regarding aggression in violence-prevention efforts, as well as direct efforts to reduce self-victimization.

Adolescent↗
PubMed1999

The gender paradox.

Explore the source record for details and available documents.

Coronary Disease↗
PubMed1998

Better outcome for women compared with men undergoing coronary revascularization: a report from the bypass angioplasty revascularization investigation (BARI)

BACKGROUND: Numerous studies have shown that women undergoing coronary revascularization procedures do so at a higher risk for an adverse outcome compared with men. However, the impact of advances in technology and improvements in techniques on in-hospital and long-term outcome after revascularization in women is unclear. METHODS AND RESULTS: We evaluated 1829 patients with symptomatic multivessel coronary disease randomized to CABG or PTCA in the Bypass Angioplasty Revascularization Investigation (BARI), of whom 27% were women. As expected, women were older (64.0 versus 60.5 years), with more congestive heart failure (14% versus 7%), hypertension (68% versus 42%), treated diabetes mellitus (31% versus 15%), and unstable angina (67% versus 61%) than men but had similar preservation of left ventricular function and extent of multivessel disease. Women assigned to surgery received the same number of total grafts but fewer internal mammary artery grafts (72% versus 85%, P<0. 01), and those assigned to angioplasty had more intended lesions (76% versus 71%, P<0.01) successfully dilated than men. At an average of 5.4 years' follow-up, crude mortality rates were similar in women (12.8%) and men (12.0%). The Cox regression model adjusting for baseline differences revealed that women had a significantly lower risk of death (relative risk, 0.60; 95% CI, 0.43 to 0.84; P=0. 003) but not a significantly lower risk of death plus myocardial infarction (relative risk, 0.84; 95% CI, 0.66 to 1.07; P=0.16) than men. CONCLUSIONS: Although the unadjusted mortality rate suggests that women and men undergoing CABG and PTCA have a similar 5-year mortality, women have higher risk profiles; consequently, contrary to previous reports, female sex is an independent predictor of improved 5-year survival after we control for multiple risk factors.

Aged↗
PubMed1998

Induction of somatic intrachromosomal recombination inversion events by cyclophosphamide in a transgenic mouse model.

Somatic intrachromosomal recombination (SICR) can result in chromosomal inversion and deletion, mechanisms which are important in carcinogenesis. We have utilised a transgenic mouse model to study SICR inversion events in spleen cells. The transgenic construct is designed so that expression of an Escherichia coli lacZ transgene only occurs in a cell when an SICR inversion event occurs in the region of the transgene. The inversion events can then be detected by histochemical staining of frozen spleen sections for transgene expression and by polymerase chain reaction across the inversion breakpoints. The spontaneous inversion frequency in spleen rose 2-fold from 1.54 +/- 0.24 x 10(-4) (mean +/- SE) in 4-month-old transgenic mice to 3.12 +/- 0.67 x 10(-4) in 22-month-old mice. Four- or 8-month-old mice were treated with a single intraperitoneal injection of cyclophosphamide, with doses ranging from 0.01 to 100 mg/kg. The animals were killed 3 days after treatment. A significant induction of SICR inversions was detected at all doses with a 3.2-fold maximum induction of inversions detected at 10 mg/kg. These results suggest that the transgenic mouse model used here may be a sensitive model for studying the role of SICR in mutation and in studying risk assessment of environmental DNA-damaging agents.

Animals↗
PubMed1997

Documentation of decline in morbidity in women undergoing coronary angioplasty (a report from the 1993-94 NHLBI Percutaneous Transluminal Coronary Angioplasty Registry). National Heart, Lung, and Blood Institute.

To determine whether there has been an improvement in the relatively unfavorable outcome of percutaneous transluminal coronary angioplasty (PTCA) in women, the 1993 to 1994 National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry collected data from 12 clinical centers that participated in the earlier registries. We compared 274 consecutive women in 1993 to 1994 with 545 consecutive women in 1985 to 1986 undergoing PTCA. Women in the 1993 to 1994 registry were older (64.3 vs 61.0 years, p <0.001) with more diabetes mellitus (34.3% vs 19.9%, p <0.001), congestive heart failure (13.7% vs 8.6%, p <0.05), and comorbid disease (19.5% vs 9.3%, p <0.001). Left ventricular function and multivessel coronary artery disease were similar between groups. Angiographic success (90.9% vs 85.1%, p <0.05) and clinical success (89.4% vs 79.4%, p <0.001) were higher in women undergoing PTCA in 1993 to 1994 than in 1985 to 1986. Whereas there was no difference in in-hospital mortality (1.5% vs 2.6%), the incidence of nonfatal myocardial infarction (1.8% vs 4.6%, p <0.05), emergency coronary artery bypass graft surgery (1.8% vs 4.6%, p <0.05), and the combined end points of death, myocardial infarction, and emergency coronary artery bypass grafting (4.4% vs 9.7%, p <0.01) were lower in women in 1993 to 1994 than in women in 1985 to 1986, respectively. Multivariate analysis revealed an odds ratio of 0.36 (95% confidence interval 0.18 to 0.72) for major complications and of 2.34 (95% confidence interval, 1.49 to 3.69) for clinical success in the 1993 to 1994 versus 1985 to 1986 registry. Therefore, despite a higher risk profile, women undergoing PTCA in 1993 to 1994 have a higher clinical success and lower major complication rate than women treated with PTCA in 1985 to 1986.

Aged↗
PubMed1997

Impact of diabetes mellitus on percutaneous revascularization (CAVEAT-I). CAVEAT-I Investigators. Coronary Angioplasty Versus Excisional Atherectomy Trial.

We examined the relation between diabetes mellitus and outcomes in patients undergoing percutaneous coronary revascularization in the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT-I), a randomized trial comparing treatment with either percutaneous transluminal coronary angioplasty or directional atherectomy for de novo lesions in native coronary arteries. Acute success and complication rates, 6-month angiographic restenosis rates, and 1-year clinical outcomes were compared between diabetic and nondiabetic patients undergoing each procedure. Acute success rates between diabetic (n = 191) and nondiabetic (n = 821) patients were similar for both revascularization techniques. Except for the need for dialysis, complication rates were also similar. Six months after atherectomy, diabetic patients had significantly more angiographic restenosis than nondiabetics (59.7% vs 47.4%) and significantly smaller minimum luminal diameters (1.20 vs 1.40 mm). Diabetics undergoing atherectomy required more frequent bypass surgery (12.8% vs 8.5%) and more repeat percutaneous revascularizations (36.5% vs 28.1%) than nondiabetics undergoing atherectomy. Restenosis rates, minimum luminal diameters and repeat revascularizations between diabetics and nondiabetics undergoing angioplasty were similar. The higher restenosis and repeat revascularization rates and the smaller minimum luminal diameter at follow-up in diabetic patients suggest that atherectomy may provide only modest benefit for these patients. The increased restenosis rate in diabetics undergoing atherectomy (but not angioplasty) requires further evaluation.

Acute Disease↗
PubMed1997

Congestive heart failure in patients with coronary artery disease: the gender paradox.

To determine whether the increased prevalence of congestive heart failure in women compared with men undergoing diagnostic cardiac catheterization is the result of a difference in the left ventricular pressure/volume relation, we retrospectively compared the clinical characteristics, left ventricular ejection fraction, and end-diastolic pressure and volume in 586 women and 1081 men undergoing diagnostic coronary angiography and left ventriculography. In comparison with men, women were older (63 vs 60 years; p = 0.0001) and had more hypertension (41% vs 31%; p = 0.0001), diabetes (18% vs 12%; p = 0.003), and symptoms of congestive heart failure (13% vs 10%; p = 0.05). In spite of this, women had a better mean left ventricular ejection fraction (61% vs 56%; p = 0.0001) and less prevalent three-vessel disease (23% vs 34%; p = 0.0001). Left ventricular end-diastolic volume index was smaller in women compared with men (73 vs 79 ml/m2; p = 0.0001) in spite of having similar left ventricular end-diastolic pressure. When patients were stratified according to left ventricular end-diastolic pressure, women had a significantly smaller end-diastolic volume than men did when left ventricular end-diastolic pressure was > or = 18 mm Hg (74 vs 86 ml/m2; p = 0.0001). In a multivariate analysis, female sex remained an independent predictor of congestive heart failure (odds ratio 1.72, 95% confidence interval 1.11 to 2.66, p = 0.02). This study suggests that diastolic dysfunction is one mechanism for the paradox of more frequent heart failure symptoms in spite of better preserved left ventricular systolic function in women. Sex appears to influence the pattern of myocardial dysfunction in patients with known or suspected coronary artery disease, but the basis for this observation remains speculative.

Coronary Disease↗
PubMed1997

Factors influencing mortality after emergency coronary artery bypass grafting for failed percutaneous transluminal coronary angioplasty.

BACKGROUND: Emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty is associated with increased mortality. METHODS: From 1981 through 1995, 117 patients at our institution underwent emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty, with an in-hospital mortality rate of 13.6%. Univariate and multivariate analyses were used to identify the factors that influenced the risk of death. RESULTS: Univariate analysis revealed that patients who died more often were women and had chronic renal failure, lower ejection fractions, and more diffuse coronary artery disease; less often received an internal mammary artery graft or an antegrade perfusion catheter; required inotropic support in the cardiac catheterization laboratory; and experienced myocardial infarction. Multivariate analysis demonstrated that the need for inotropic support in the cardiac catheterization laboratory was the best predictor of perioperative death. CONCLUSIONS: Patients with a reduced ejection fraction in whom percutaneous transluminal coronary angioplasty fails, antegrade perfusion does not produce a response, and myocardial infarction occurs are more likely to die after coronary artery bypass grafting. The risk appears to be highest for patients who require inotropic support in the cardiac catheterization laboratory.

Analysis of Variance↗
PubMed1997

A class IV chitinase is highly expressed in grape berries during ripening.

Chitinase activity increased markedly at the onset of ripening in grape (Vitis vinifera L.) berries and continued to increase throughout the sugar accumulation phase of berry development. In contrast, beta-1,3-glucanase activity was not detected in grape berries at any stage of development. Two closely related chitinase cDNAs (VvChi4A and VvChi4B) were cloned from grapes. Sequence and Southern analysis indicate that these two clones may represent alleles of the same gene. The predicted proteins are acidic and have a signal peptide followed by a cysteine-rich, chitin-binding domain and a catalytic region. An analysis of their sequences indicates that they are class IV chitinase. The deduced protein sequence of VvChi4A has a high level of identity with the 32- and 28-kD chitinases present as haze proteins in wine. Expression of VvChi4 was high in berries and low in flowers but was not detected in leaves, roots, or seeds. No expression was detected in berries 2 to 8 weeks postflowering, but expression was high 12 to 16 weeks postflowering, which coincided with sugar accumulation and an increase in chitinase activity. Constitutive expression of VvChi4 appears to be fruit-specific and induced at high levels in grapes during ripening.

Amino Acid Sequence↗
PubMed1996

Relation between estrogen replacement therapy and restenosis after percutaneous coronary interventions.

OBJECTIVES: We attempted to determine the relation between estrogen replacement therapy and the rate of restenosis after coronary angioplasty and atherectomy. BACKGROUND: Although estrogen replacement therapy in women has been associated with a reduction in cardiovascular events and improvement in endothelial function, no study has examined whether estrogen reduces restenosis rates after percutaneous coronary interventions. METHODS: A total of 204 women enrolled in the Coronary Angioplasty Versus Excisional Atherectomy Trial with angiographic follow-up were contacted, and their menopausal and estrogen replacement status was determined. Late loss in minimal lumen diameter, late loss index, minimal lumen diameter, rate of restenosis > 50% and actual percent of stenosis were compared in estrogen users and nonusers by quantitative coronary angiography at 6-month follow-up. RESULTS: Late loss in minimal lumen diameter was significantly less in women using estrogen than in nonusers (-0.13 vs. -0.46 mm, p = 0.01). A regression analysis of the determinants of late loss in minimal lumen diameter revealed that estrogen use was the single most important predictor of subsequent late loss (F = 13.38, p = 0.0006). Formal testing revealed a highly significant interaction between the use of estrogen and intervention (angioplasty or atherectomy). Women undergoing atherectomy who received estrogen had a significantly lower late loss index (0.06 vs. -0.63, p = 0.002), less late loss (0.06 vs. -0.61 mm, p = 0.0006), larger minimal lumen diameter (p = 0.044) and lower restenosis rates (p = 0.038 for > 50% stenosis) than those not using estrogen. In contrast, estrogen had minimal effects on restenosis end points after angioplasty. CONCLUSIONS: This study demonstrates the potential for estrogen replacement therapy to reduce angiographic measures of restenosis in postmenopausal women after coronary intervention, particularly in those undergoing atherectomy.

Aged↗
PubMed1995

Intrapericardial basic fibroblast growth factor induces myocardial angiogenesis in a rabbit model of chronic ischemia.

The objective of this study was to determine whether basic fibroblast growth factor (bFGF), a known angiogenic factor, can promote new vessel growth when infused within the pericardial space in a model of chronic myocardial ischemia. Intravenous angiotensin II (AII) was infused to induce left ventricular hypertrophy and concomitant ischemia in New Zealand white rabbits. Basic FGF was infused into the intrapericardial space with an osmotic pump. Animals were assigned to one of four groups: group 1 received intrapericardial bFGF and intravenous AII, group 2 received intrapericardial bFGF and intravenous saline solution, group 3 received intrapericardial albumin and intravenous AII, and group 4 received intravenous AII only. Epicardial angiogenesis was graded histologically on a scale of 0 to 2. Animals receiving intravenous administration of AII displayed left ventricular hypertrophy that disproportionately affected the interventricular septum with a wall thickness of 5.62 +/- 1.00 mm versus 3.98 +/- 0.61 mm in the AII group and the saline solution control group, respectively (p < 0.005). A highly localized angiogenic effect of bFGF was observed. The mean angiogenesis scores were 1.9, 1.4, 1.3, and 0.2 (p < 0.001) with an angiogenesis score of 2 (marked increase in vascularity) noted in 86%, 40%, 43%, and 0% of hearts in groups 1 through 4, respectively. We conclude that intrapericardial bFGF enhances new epicardial small-vessel growth in a rabbit model; furthermore this effect is enhanced in the presence of left ventricular hypertrophy.

Analysis of Variance↗
PubMed1995

Coronary angioplasty and surgical revascularization: emerging concepts.

Early reports from the NHLBI PTCA Registry showed that women undergoing percutaneous transluminal coronary angioplasty (PTCA) had lower acute success rates and higher procedural complication rates than men. Similarly, most larger scale studies that have evaluated the differences in outcome between men and women undergoing surgical revascularization have noted a higher operative mortality rate in women. Some, but not all, of these differences are secondary to the higher baseline cardiovascular risk profile and smaller coronary artery diameter found in women. This article reviews the evolution of coronary angioplasty and bypass graft surgery as viable revascularization strategies in women with a focus on gender differences in baseline characteristics, acute outcome and long-term efficacy.

Angioplasty, Balloon, Coronary↗