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L A Hutchinson

Publications and source records attributed to L A Hutchinson.

5 recordsLinked to original sources
PubMed1998

Does radiofrequency ablation induce a prethrombotic state? Analysis of coagulation system activation and comparison to electrophysiologic study.

INTRODUCTION: Although thromboembolism is an uncommon complication of radiofrequency (RF) ablation, some preliminary reports have suggested that RF ablation results in activation of the coagulation system, possibly increasing this risk. We hypothesized that the insertion of intravenous catheters and their prolonged intravenous placement rather than RF ablation activates the coagulation cascade. METHODS AND RESULTS: Thirty-seven patients, group 1 (n = 21) during RF ablation, and group 2 (n = 16) during routine electrophysiologic studies (EPS), were studied prospectively. Blood was drawn for coagulation and fibrinolytic studies following insertion of venous sheaths (T0), following catheter placement (T1), and 1 hour after completion of RF ablation or EPS (T2). Conversion of prothrombin to thrombin was measured using thrombin-antithrombin complex (TAT) and prothrombin activation peptide (F1+2), and fibrinolytic activity was assessed using D-dimer concentration. Levels of D-dimer increased in group 1 from 823.52+/-323.52 ng/mL at T0 to 1,314.28+/-297.63 ng/mL at T2 (P = 0.005), and in group 2 from 658.15+/-161.70 ng/mL at T0 to 1625+/-641.45 ng/mL at T2 (P = 0.064). TAT levels increased from to 27.74+/-5.6 microg/L at T0 to 52.99+/-5.93 microg/L at T2 in group 1 (P = 0.09), and from 19.79+/-5.14 microg/L at T0 to 73.5+/-24.15 microg/L at T2 in group 2 (P = 0.05). F1+2 concentration increased from 1.52+/-0.30 nmol/L at T0 to 3.06+/-0.41 nmol/L at T2 in group 1 (P = 0.004), and from 1.32+/-0.30 nmol/L at T0 to 3.11+/-0.46 nmol/L at T2 in group 2 (P = 0.087). There was no significant difference in the concentration of the three coagulation variables between group 1 and group 2 at any given time point. No correlation was demonstrable between concentration of D-dimers, TAT, or F1+2 and variables of RF delivery such as cumulative energy, number of RF energy applications, or number of impedance rises. However, a significant positive correlation (r = 0.65, P<0.01) was noted between the duration of the RF ablation procedure and the concentration of D-dimers. CONCLUSION: We conclude that activation of the coagulation cascade in RF ablation procedures is not related to the delivery of RF energy, but is related to the placement of intravascular catheters and to the duration of the ablation procedure.

Adult↗
PubMed1994

Is there detrimental gender bias in preoperative cardiac management of patients undergoing vascular surgery?

BACKGROUND: To investigate the possibility of gender bias in the cardiac management of patients who undergo peripheral vascular surgery, we examined the hospital data and outcomes for 350 adult men and 128 women who underwent vascular surgery from September 1987 to December 1991. METHODS AND RESULTS: There were no significant differences between the two groups in age at operation, incidence of standard risk factors for myocardial infarction, or incidence or duration of episodes of perioperative silent ischemia. Nevertheless, a significantly lower percentage of women than men had undergone prior coronary bypass procedures (6.3% and 17.1%, respectively; P < .01), an apparent example of gender bias. However, there was no significant difference in the incidence of perioperative myocardial infarction in women (3.9%) compared with men (4.0%). Furthermore, actuarial analysis showed that at 24 months after operation a significantly higher percentage of women (77.9%) had escaped late cardiac death and cardiac complications than men (71.9%; P < .05). CONCLUSIONS: These findings indicate that apparent gender bias in the preoperative cardiac management of this group of women who underwent vascular surgery may have had no detrimental effect on short- and long-term incidence of cardiac death and complications, and may represent sound clinical judgment rather than true bias. However, the possibility that female patients might have had even better short- and long-term cardiac results if they had undergone more preoperative cardiac revascularization cannot be discounted.

Actuarial Analysis↗
PubMed1988

Growth hormone and insulin-like growth factor-I accelerate PMSG-induced differentiation of granulosa cells.

To investigate the nature of the interactions between growth hormone (GH), insulin-like growth factor-I (IGF-I) and follicle stimulating hormone (FSH), their temporal and dose-related effects on steroidogenesis were studied in granulosa cells from stilboestrol-treated immature rats, stimulated in vitro with pregnant mare's serum gonadotropin (PMSG) or FSH. GH in the presence of PMSG enhanced aromatase activity and progesterone synthesis above that induced by maximally stimulating doses of PMSG alone, and accelerated PMSG-induced peak levels for both progesterone and aromatase activity. IGF-I also enhanced PMSG-induced aromatase activity and progesterone production, and accelerated their peak responses in a similar fashion to the effects observed for GH. The stimulatory actions of IGF-I could still be observed after the removal of FSH from the cultures, and appeared to be partly independent of cAMP. It is concluded that both GH and IGF-I act on FSH-induced granulosa cells to accelerate the differentiation of the follicular cell to a lutein cell.

Animals↗
PubMed1987

Effects of bovine inhibin, transforming growth factor-beta and bovine Activin-A on granulosa cell differentiation.

To determine whether inhibin and its related peptides might act locally to control granulosa cell function and differentiation, the dose- and time-dependent effects of bovine inhibin, the homo-dimer of the beta-chain of bovine inhibin (Activin-A) and porcine TGF beta on rat granulosa cell aromatase activity and progesterone synthesis were investigated in vitro. TGF beta enhanced FSH-induced aromatase activity and progesterone synthesis, and accelerated the peak response for progesterone synthesis. Activin-A on the other hand, augmented FSH-induced aromatase activity while arresting progesterone synthesis, and anti-luteinization effect. By contrast, exogenous inhibin had no detectable effect on the steroidogenic potential of these cells. Thus TGF beta and Activin, unlike their similar effects on the release of FSH by the pituitary, appear to affect ovarian granulosa cell function in different fashion, under conditions where inhibin itself has no effect.

Activins↗