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At least 1,153 records · Page 64Linked to original sources

PubMed1996

[Quantitative evaluation of the dynamics of the coronary wall in man: description of a new method based on tridimensional time-dependent reconstruction of intravascular ultrasonographic images].

BACKGROUND: Intravascular ultrasound imaging provides information on vascular lumen and arterial wall structure and it has potential application in arterial wall dynamic study. The aim of this study was to develop a computer assisted system for analysing digitised cross sectional ultrasound images of coronaries to easily display and quantify coronary dynamic and its relationship with arterial wall morphology. METHODS AND RESULTS: To extract the anatomical regions of interest from the digitised sonograms, automatic image segmentation and interactive procedures for manual correction were implemented. This step included the recognition of the lumen edge and an analysis of gray level intensity of the wall. Subsequently, a virtual 3D reconstruction of lumen and vessel wall was done in a Cartesian system where the XY plane was parallel to each cross-sectional sonogram, while the Z axis corresponded to the acquisition time. The baricentre of vascular lumen was used as a reference for alignment. We obtained a cylinder-like solid representing the behavior of the arterial cross-sectional sonogram in time, with the possibility to look either at the wall or at the lumen. In this virtual solid it was possible to measure the variation of lumen area and of 16 hemidiameters; in addition, the derivatives of these values, allowing an estimate of the velocity of events, can be obtained. CONCLUSIONS: The described computerised system for the analysis of intravascular ultrasound images could become a very useful tool for 3D representation and quantitative monitoring of coronary compliance and their relationship with segmental arterial wall morphology.

Coronary Vessels↗

PubMed1991

Penetration of the systemic blood pressure into the microvasculature of rat skeletal muscle.

A series of arterial micropressure measurements in different skeletal muscles of the Wistar-Kyoto and spontaneously hypertensive rat is presented. The micropunctures were carried out with minimal surgical intervention through small skin incisions and the micropressures were recorded simultaneously with femoral artery pressures. The measurement sites were located at the entry points into the muscles for the proximal and distal supply arteries and at the midpoint of the arteriolar arcade bridge which directly connects these two supply arteries in the center of the muscle parenchyma. In contrast to feed artery pressure values from exteriorized muscles, which in the past have been reported to be as low as 40 mm Hg, the current mean pressure values are substantially higher and in the range between 70 and 100 mm Hg, equivalent to 70 to 90% of the mean systemic pressure. Systolic and diastolic values exhibit comparable trends to the mean pressures and they are similar in muscles at different locations in the body. Although in spontaneously hypertensive rats the absolute pressures were significantly higher compared with their controls, the normalized pressures were virtually identical at the locations used in this study. These data indicate that the absolute pressure in the central arteries of spontaneously hypertensive animals is reduced to a greater degree than in Wistar-Kyoto rats, while in both strains the major pressure reduction in skeletal muscle still occurs in the microcirculation.

Animals↗

PubMedDate not supplied

Behavior changes & disease prevention: MCW research shows effectiveness of HIV/AIDS risk reduction interventions. Medical College of Wisconsin.

Many of the diseases that cause premature illness and death--including some cancers, heart disease, and AIDS--could be prevented if persons made behavior changes to reduce their risk for developing the illnesses. Over the past two decades, there have been great advances in our scientific understanding of how to promote health risk behavior change. This paper briefly reviews elements and examples of effective behavior change interventions, including programs that can be offered in service settings as well as community-level interventions. The prevention of diseases through behavioral public health interventions requires the investment of funds but can reduce burdens on health care systems, reduce the human toll caused by premature deaths, and be highly cost-effective. A remarkable number of diseases could be prevented if individuals were effectively assisted in changing the risk behaviors responsible for those illnesses. The causal association between cigarette smoking and lung cancer, other pulmonary diseases, and cardiovascular disease is well-known, and millions of premature deaths could be prevented if people stopped smoking cigarettes. Deaths due to cardiovascular disease could be dramatically reduced if persons made behavioral and lifestyle changes to improve their fitness through exercise, obesity reduction, and maintenance of low blood cholesterol levels. The World Health Organization estimates that over 45 million persons worldwide have already contracted HIV infection, and nearly 1 million of these cases are in the United States. Over 40,000 Americans continue to contract HIV infection each year. Virtually every new case of HIV infection is preventable if individuals at risk made changes in their sexual or drug use practices. While lung cancer, cardiovascular disease, and AIDS are three of the clearest examples, persons' behavior plays a direct or a contributing role in the development of many other diseases that cause premature death or that worsen health and life quality. Recognition of the link between behavior and preventable illness--and recognition that enormous health, economic, and quality of life benefits could be realized through healthier behavior patterns--is not new. We have known all of this for a long time. We have also known for a very long time that helping people to successfully change risky behavior habits is often very difficult. Over the past 20 years, a field of scientific study and applied practice has developed with the purpose of better understanding why persons engage in health risk behavior patterns and developing approaches to help people change these patterns. Under the rubric of "behavioral medicine", this field makes use of behavioral science theory and behavior change techniques applied to health and disease prevention.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Contraception and the risk of type 2 diabetes mellitus in Latina women with prior gestational diabetes mellitus.

CONTEXT: Effective contraception is essential in women with prior gestational diabetes mellitus (GDM) but should not increase their already substantial risk of developing type 2 diabetes. OBJECTIVE: To determine whether exposure to low-dose oral contraceptives increases the risk of developing type 2 diabetes mellitus in women with recent GDM. DESIGN: Retrospective cohort study of 904 Latinas with GDM who gave birth between January 1987 and March 1994, in whom postpartum diabetes was excluded at 4 to 16 weeks post partum. INTERVENTIONS: At their initial postpartum visit, 443 women selected a nonhormonal form of contraception, 383 received a low-dose, estrogen-progestin combination oral contraceptive (OC), and 78 breast-feeding women received the progestin-only OC. When breast-feeding ended, patients initially taking progestin-only OCs were switched to combination OCs. Patients were followed up periodically with oral glucose tolerance tests for up to 7 1/2 years. MAIN OUTCOME MEASURES: Person time was used to compute unadjusted average annual incidence rates of developing diabetes mellitus, as defined by the National Diabetes Data Group Criteria. Survival analysis was used to compute the unadjusted cumulative incidence rates and adjusted relative risks of diabetes mellitus. RESULTS: The unadjusted average annual incidence rates of type 2 diabetes mellitus were 8.7%, 10.4%, and 26.5%, respectively, for patients using nonhormonal forms of contraception, combination OCs, and progestin-only OCs. Cumulative incidence rates were virtually identical for patients with uninterrupted use of combination OCs and nonhormonal forms of contraception, but patients using progestin-only OCs developed diabetes mellitus more rapidly during the first 2 years of use. After adjustment for potential confounding factors, the use of progestin-only OCs almost tripled the risk of type 2 diabetes mellitus compared with equivalent use of low-dose combination OCs (adjusted relative risk, 2.87; 95% confidence interval, 1.57-5.27). The magnitude of this risk increased with duration of uninterrupted use. CONCLUSION: Progestin-only OCs were associated with an increased risk of diabetes in breast-feeding Latinas with recent GDM and probably should be prescribed with caution, if at all, in these women. Long-term use of low-dose combination OCs did not increase the risk of type 2 diabetes compared with use of nonhormonal contraception. Thus, combination OCs do not appear to increase the risk of diabetes in non-breast-feeding women with recent GDM.

Cohort Studies↗

PubMed1997

Depressed autoantibody synthesis in Trypanosoma cruzi-infected rats born to mothers undergoing this infection during pregnancy.

Earlier work indicated that Trypanosoma cruzi infection in pregnant rats decreased the amount of myocardial damage that developed in their chronically infected offspring. Given the suspected role of autoimmune mechanisms in the generation of chronic myocarditis, we evaluated whether this maternal intervention was likely to affect the synthesis of autoantibodies in infected young. Autoantibodies were investigated against molecules exhibiting cross-reactivity with T. cruzi antigens or not, that is cerebroside sulphate (sulphatide) and actin, respectively. Female '1' rats (75 days old) that had been mated with syngeneic sires were separated into two groups, one challenged with living trypomastigotes at 7, 14 and 21 days following mating, and the other one given physiologic saline at the same intervals. At the time of weaning, offspring were injected with 10(6)/T. cruzi to constitute two infected groups: young born to infected mothers (InMoTc) and young delivered by uninfected mothers (CoMoTc). Serum antibodies were investigated by ELISA at 30 and 60 days post-infection, which represents acute and chronic infection, respectively. T. cruzi infection was associated with the production of anti-sulphatide antibodies, but the phenomenon was significantly less evident in InMoTc young and virtually unnoticeable during their chronic infection. Unlike the anti-sulphatide results, levels of anti-actin antibodies showed no differences between CoMoTc and InMoTc rats when compared during acute or chronic infection. The decreased production of anti-sulphatide autoantibodies of InMoTc offspring may be due to a modification of the immune repertoire of offspring because of the contact with parasite antigens during ontogeny.

Actins↗

PubMed1995

Molecular mechanisms of liver fibrogenesis--a homage to the role of activated fat-storing cells.

During the last few years, considerable progress has been made in the dissection of cellular and molecular mechanisms of hepatic fibrogenesis. The disease, initiated by hepatocellular damage and perpetuated by inflammatory reactions, results not only in an overall increase in extracellular matrix (ECM) but also in molecular and histological rearrangement of virtually all matrix molecules including collagens, structural glycoproteins, proteoglycans and hyaluronan. These alterations of ECM cause severe clinical (e.g. hemodynamic) complications and further metabolic changes in the whole organ. Perisinusoidal fat (retinoid)-storing cells have been identified as the (precursor) cell type mainly responsible for matrix production in the diseased liver. However, these cells have to be activated, i.e. stimulated to proliferate, to transform phenotypically to myofibroblasts and to express matrix genes before full competency for fibrogenesis is reached. Multiple cell interactions with Kupffer cells, platelets, endothelial cells and hepatocytes mediated by various cytokines and growth factors (e.g. TGF-beta 1, TGF-alpha, PDGF, FGF, IGF-1) are involved in the mechanism of fat-storing cell activation which is the common and central pathogenetic mechanism in fibrogenesis. A three-step cascade model of fat-storing cell activation is proposed, which offers target mechanisms for possible anti-fibrotic interventions.

Adipocytes↗

PubMed2004

[Transcultural approach in perinatality].

Over the last years, our approach to the perinatal period has become more complex with the integration of new tools designed for better comprehension and cultural awareness. In this area of medical practice, perhaps more than in others, the complementary contribution of different approaches, ways of thinking, and practical interventions is essential. Pregnancy, delivery, early mother-infant interactions, and construction of the parent-child relationship involve not only profoundly intimate, intrapsychic and intersubjective events but also medical, social, and cultural events which all become a part of the process of transmitting life in an open group. The junction between somatic, intrapsychic, intersubjective and cultural elements was analyzed in the everyday clinical setting of a multicultural suburban area near Paris. The therapeutic impact of this perspective was noted. Two therapeutic processes specific to the perinatal period were studied: the need to assist vulnerable migrant mothers in reconstructing their defense systems (possible because of the psychic transparency and the primary maternal priority of this special period of life) and direct work with the baby. Working directly with the baby and not only the mother creates an open triad around the baby. This baby/mother/therapist group relationship develops progressively and is initially perceived as a virtual group before developing into a more concrete transferential relationship based on familial and social resources. The perinatal clinic is by definition a very pluridisciplinary and very context-related unit.

Child↗

PubMed2004

Decreased tumor necrosis factor-induced adhesion of human monocytes to endothelial cells after moderate alcohol consumption.

BACKGROUND: Moderate alcohol consumption protects against ischemic heart disease, possibly through an antiinflammatory effect. However, little is known about the mechanisms by which alcohol may interfere in the development of atherosclerosis. OBJECTIVE: We analyzed the effects of 2 alcoholic beverages with high (red wine) or low (gin) polyphenolic content on human monocyte adhesion to an endothelial cell line (Ea.hy926). DESIGN: This was a randomized, crossover trial with 8 healthy men. After a washout period, the subjects received 30 g ethanol/d as red wine or gin for 28 d. Before and after each intervention, a dietary survey and laboratory analysis were performed. Adhesion of human monocytes to endothelial cells was measured in basal and stimulated [by tumor necrosis factor alpha (TNF-alpha)] conditions. Adhesion molecules involved in monocyte-endothelium interactions were determined on the cell surface. RESULTS: The mean expression of very late activation antigen 4 on monocytes significantly decreased after red wine intake [by 18% (95% CI: 33%, 3%); P = 0.022]. Monocyte adhesion significantly increased after TNF-alpha stimulation of endothelial cells. This increase, however, was 39% less (95% CI: 48%, 35%; P = 0.049) after gin intake than after the respective washout period and was nearly abolished by red wine intake [96% less than after the respective washout period (95% CI: 142%, 76%); P < 0.001]. The reduction after red wine intake was significantly different from that after gin intake (P = 0.014). CONCLUSIONS: TNF-alpha-induced adhesion of monocytes to endothelial cells was virtually abolished after red wine consumption but was only partially reduced after gin consumption. This effect may be due to the down-regulation of adhesion molecules on the monocyte surface.

Adult↗

PubMedDate not supplied

Comparison of self-expanding polyethylene terephthalate and metallic stents implanted in porcine iliac arteries.

PURPOSE: Comparison of the biocompatibility of self-expanding polyethylene terephthalate (PET) stents with self-expanding metallic stents (Wallstents). METHODS: Diameter- and length-matched PET stents and Wallstents were symmetrically implanted in the paired iliac arteries of 13 crossbred domestic swine. Stent deployment was studied angiographically and with intravascular ultrasound immediately after stent implantation. The angiographic stented lumen diameter was measured using quantitative vessel analysis before, immediately after stenting, and at 6-week follow-up. Cross-section histopathology and area morphometry were performed. RESULTS: Immediately poststenting, intravascular ultrasound revealed proximal dislocation of 5 of the 13 PET stents, whereas all metal stents were firmly embedded at the implantation site. At 6-week follow-up, three of the remaining PET stents were totally or subtotally occluded by organized thrombus, whereas all metal stents were patent. Compared with immediately poststenting, the angiographic lumen diameter within the five remaining PET stents was reduced by 30%, and that of the metallic stents was virtually unaltered (p < 0.02). This observation was confirmed by postmortem morphometry, wherein the PET-stented vessel segments a diameter stenosis of 40% was measured vs only 9% in the metallic stents (p < 0.0001). CONCLUSION: PET-stent deployment is difficult to control due to the lack of radiopacity of this stent. PET stents seem to be more thrombogenic and lead to significantly more neointimal proliferation than metallic stents.

Animals↗

PubMed2004

Radial versus femoral approach for percutaneous coronary diagnostic and interventional procedures; Systematic overview and meta-analysis of randomized trials.

OBJECTIVES: We sought to compare, through a meta-analytic process, the transradial and transfemoral approaches for coronary procedures in terms of clinical and procedural outcomes. BACKGROUND: The radial approach has been increasingly used as an alternative to femoral access. Several trials have compared these two approaches, with inconclusive results. METHODS: The MEDLINE, CENTRAL, and conference proceedings from major cardiologic associations were searched. Random-effect odds ratios (ORs) for failure of the procedure (crossover to different entry site or impossibility to perform the planned procedure), entry site complications (major hematoma, vascular surgery, or arteriovenous fistula), and major adverse cardiovascular events (MACE), defined as death, myocardial infarction, emergency revascularization, or stroke, were computed. RESULTS: Twelve randomized trials (n = 3,224) were included in the analysis. The risk of MACE was similar for the radial versus femoral approach (OR 0.92, 95% confidence interval [CI] 0.57 to 1.48; p = 0.7). Instead, radial access was associated with a significantly lower rate of entry site complications (OR 0.20, 95% CI 0.09 to 0.42; p < 0.0001), even if at the price of a higher rate of procedural failure (OR 3.30, 95% CI 1.63 to 6.71; p < 0.001). CONCLUSIONS: The radial approach for coronary procedures appears as a safe alternative to femoral access. Moreover, radial access virtually eliminates local vascular complications, thanks to a time-sparing hemostasis technique. However, gaining radial access requires higher technical skills, thus yielding an overall lower success rate. Nonetheless, a clear ongoing trend toward equalization of the two procedures, in terms of procedural success, is evident through the years, probably due to technologic progress of materials and increased operator experience.

Angioplasty, Balloon, Coronary↗

PubMed1976

The determinants of onset of mitral valve prolapse in the systolic click-late systolic murmur syndrome.

The onset of mitral valve prolapse and its close correlate, the time of systolic click, vary considerably with different physiologic and pharmacologic interventions. In order to explain the mechanism responsible for these alterations, the effects of tilt and amyl nitrite inhalation on left ventricular dynamics and the time of the systolic click were studied by analyzing echocardiograms and simultaneously recorded phonocardiograms in 14 patients with mitral valve prolapse and mid-systolic click. The patients were studied in the supine position, with 40-60 degrees head-up tilt and after amyl nitrite inhalation. Computer analysis of the recordings was used to measure the left ventricular end-diastolic diameter, the click diameter (left ventricular diameter at the time of mid-systolic click), the maximal velocity of circumferential fiber shortening (max VCF), and the time interval between the first heart sound and systolic click (S1-X). With tilt and amyl nitrite, shortening of the S1-X interval b y an average of 44 and 87 msec, respectively, was observed. The click diameter, however, remained virtually constant with both maneuvers. Earlier prolapse after tilt was due to a decrease in the end-diastolic diameter from 5.03 +/- 0.74 to 4.50 +/- 0.68 cm (P less than 0.001) with no change in max VCF. Immediately after amyl nitrite, earlier prolapse was due to an increase of VCF in the preprolapse period, with max VCF increasing from 2.15 +/- 0.27 to 3.06 +/- 0.40 circ/sec (P less than 0.001), there being no change in the end-diastolic diameter up to this time. The constant click diameter indicates that the abnormal valve motion in this syndrome occurs at a critical left ventricular chamber size. Variations in the onset of prolapse are caused by changes in left ventricular end-diastolic dimensions and the velocity of circumferential fiber shortening in the preprolapse period.

Adult↗

PubMed2001

Plants as de-worming agents of livestock in the Nordic countries: historical perspective, popular beliefs and prospects for the future.

Preparations derived from plants were the original therapeutic interventions used by man to control diseases (including parasites), both within humans and livestock. Development of herbal products depended upon local botanical flora with the result that different remedies tended to develop in different parts of the world. Nevertheless, in some instances, the same or related plants were used over wide geographic regions, which also was the result of communication and/or the importation of plant material of high repute. Thus, the Nordic countries have an ancient, rich and diverse history of plant derived anthelmintic medications for human and animal use. Although some of the more commonly used herbal de-wormers were derived from imported plants, or their products, many are from endemic plants or those that thrive in the Scandinavian environment. With the advent of the modern chemotherapeutic era, and the discovery, development and marketing of a seemingly unlimited variety of highly efficacious, safe synthetic chemicals with very wide spectra of activities, herbal remedies virtually disappeared from the consciousness--at least in the Western world. This attitude is now rapidly changing. There is a widespread resurgence in natural product medication, driven by major threats posed by multi-resistant pest, or disease, organisms and the diminishing public perceptions that synthetic chemicals are the panacea to health and disease control. This review attempts to provide a comprehensive account of the depth of historical Nordic information available on herbal de-wormers, with emphasis on livestock and to provide some insights on potentially rewarding areas of "re-discovery" and scientific evaluation in this field.

Animals↗

PubMed1991

Reducing the cesarean section rate in a rural community hospital.

OBJECTIVE: To determine the success of a program designed to reduce the cesarean section rate in a rural community hospital, to identify reasons for any reduction in the rate and to identify any accompanying increases in the maternal and neonatal morbidity and mortality rates. DESIGN: Longitudinal study of modes of delivery. SETTING: A 44-bed community hospital with a medical staff of nine family physicians serving a population of 9000. PATIENTS: All 1161 women who gave birth at the hospital from Jan. 1, 1985, to Dec. 31, 1989. Routinely recorded data were manually extracted from medical charts and entered into a computer database. INTERVENTION: The guidelines of the National Consensus Conference on Aspects of Cesarean Birth (NCCACB) for vaginal birth after cesarean section (VBAC), management of breech presentation and the diagnosis of dystocia requiring cesarean section were introduced at the hospital in 1985. OUTCOME MEASURES: The annual overall cesarean section rates and the rates among nulliparous women, multiparous women eligible for VBAC and multiparous women ineligible for VBAC. RESULTS: The overall cesarean section rate decreased from 23% in 1985 to 13% in 1989 (p = 0.001). Among the nulliparous women the rate decreased from 23% to 12%, but the difference was insignificant (p = 0.069); this decrease was due to a drop in the number of dystocia-related cesarean sections. The rate among VBAC-eligible multiparous women decreased from 93% to 36% (p less than 0.001) because of an increased acceptance of VBAC by the patients and the physicians. The rate among multiparous women ineligible for VBAC was virtually unchanged. There were 20 neonatal transfers to an intensive care unit, with no tendency toward an increase over the study period. None of the mothers died; one newborn, of a nulliparous woman, died from a prolapsed umbilical cord. CONCLUSIONS: The program was accompanied by a significant decrease in the cesarean section rate. Rural hospitals with facilities and personnel for emergency cesarean sections should consider the introduction of a similar program.

Alberta↗

PubMed1994

Magnetic resonance spectroscopy studies of human muscle.

The use of MRS has become more widespread as cost and availability have improved. It has been demonstrated that MRS of human skeletal muscle can play a significant role in (1) understanding healthy muscle metabolism and the mechanisms of muscle fatigue, (2) understanding the effects of disease on muscle metabolism and function, (3) monitoring the efficacy of therapeutic intervention, and (4) the confirmation of disease diagnoses. The results of the 31P MRS studies of disease are summarized in the Table 1. A few conditions (McArdle's, PFK deficiency) are associated with failure to develop acidosis during exercise. This response appears to be relatively specific to these metabolic myopathies. For most of the conditions reviewed here, however, the metabolic findings of reduced PCr/Pi and greater acidosis during exercise with impaired recovery of PCr/Pi and pH are very similar. The nonspecificity of the MRS results suggests the possibility that a common mechanism may be at work in all of these diseases. A major question to arise from clinical studies using MRS concerns the extent to which deconditioning may have played a role in some of these findings. This is because conditions associated with muscle weakness, rapid fatiguability, and muscle pain during or following vigorous physical activity may also be those that lead to deconditioning. In virtually all studies reviewed here, healthy, active subjects were used as controls. There are no examples in which controls were appropriately matched to the subjects for their level of conditioning. Conditioning could be assessed by questionnaire, activity logs, activity monitoring devices, or measurements of conditioning effects such as maximal oxygen consumption. The role of deconditioning in the decreased quality of life of persons with chronic diseases has not been fully explored. Future studies of chronic disease using MRS should combine MRS with other techniques to further probe the mechanisms of muscle metabolism under various conditions, and the extent to which these mechanisms are sensitive to the level of physical conditioning.

Humans↗

PubMed2005

Modality-integrated magnetic catheter tracking for x-ray vascular interventions.

A novel setup for the integration of a magnetic tracking system (MTS) into a catheter laboratory environment by attaching the field generator of the MTS to the C-arm of the x-ray system was investigated. The metal interference of the x-ray system with the MTS then becomes static and can be calibrated. The registration of a tracked catheter to 2D live x-ray images with high and well-defined accuracy is thus possible for arbitrary C-arm positions. Interference with imaging by blocking the field of view is avoided. Real-time registration methods to maintain the registration of the catheter also to static 2D or 3D images (roadmaps), regardless of the C-arm rotation during catheter tracking, were investigated. Residual registration errors of the tracked catheter with respect to the static roadmaps (2D and 3D) were reduced by using the vessel geometry and shape information. The algorithms potentially allow for motion correction (e.g. due to respiration). Using the shape-based correction algorithms the average registration accuracies to static roadmaps for different C-arm angulations and catheter positions were determined to be 3.3-4.2 mm. The magnetic registration of the C-arm was furthermore allowed to compute the imaging geometry (position of the C-arm) and to produce virtual angiographic preview images before contrast injection and x-ray dose application. Thus, optimal projection geometries and collimator settings for the target region can be chosen in an 'off line' fashion. The proposed MTS-supported navigation setup on both 3D (static) and 2D (live and static) roadmaps merges the high resolution and real-time feedback of 2D x-ray images with the navigation support from 3D static images.

Algorithms↗

PubMedDate not supplied

Periosteal readhesion after brow-lift in New Zealand white rabbits.

OBJECTIVES: To define the postoperative time interval required for elevated periosteum to readhere to the skull and regain its preoperative strength, and to evaluate whether fixation of the periosteum affects this interval or the strength of postoperative readhesion. DESIGN: Prospective analysis of variance and covariance with repeated measures. SUBJECTS: Thirty-six New Zealand white rabbits, each serving as its own control. INTERVENTIONS: Subperiosteal elevation was performed on one side of the skull, leaving the contralateral periosteum untouched. The periosteum in half of the subjects was lifted and fixed to a resorbable screw, with the comparison group undergoing subperiosteal elevation only, without lifting and fixation. Several adhesion characteristics were subsequently examined at postoperative weeks 1, 3, 5, 7, 8, 9, 10, 11, and 12. Half of the subjects were assessed histologically to determine attachment of periosteum onto underlying bone. The other half underwent analysis of periosteal readhesion strength. RESULTS: The 3 independent measures of periosteal adherence to the skull all lacked significant differences between sides after the first postoperative week. Blinded histologic analysis showed no evidence of ongoing periosteal healing and demonstrated no difference between operated-on and nonoperated-on sides. Analysis of periosteal stiffness (P =.76) and energy density (P =.74) also demonstrated no significant differences between sides. CONCLUSIONS: Periosteal readhesion after surgical elevation is virtually complete by the seventh postoperative day. In addition, tension secondary to periosteal elevation with suspension has no influence on postoperative healing. These findings will contribute to the debate regarding the most appropriate brow-lift fixation technique.

Absorbable Implants↗

PubMed1987

Influence of baseline hemodynamic status and sympathetic activity on the response to nicardipine, a new dihydropyridine, in patients with hypertension or chronic congestive heart failure.

We evaluated the immediate hemodynamic response to nicardipine, administered as an intravenous bolus and 30-minute sustaining infusion, in 10 patients with systemic hypertension (HTN) and 10 patients with chronic congestive heart failure (CHF). Baseline systemic vascular resistance and the response to nicardipine for HTN (1968 +/- 657 to 905 +/- 256 dynes X sec X cm-5) and CHF (2002 +/- 988 to 1089 +/- 216 +/- 99 dynes X sec X cm-5) were virtually identical (P less than 0.01). In both groups there was a significant increase of cardiac index in response to afterload reduction: HTN, 2.70 +/- 0.46 to 4.47 +/- 1.01; CHF, 1.90 +/- 0.33 to 2.88 +/- 0.80 L/min/m2 (P less than 0.01), so that a negative inotropic effect was not evident. In HTN the increase in cardiac index was primarily the result of reflex increase of heart rate (67 +/- 16 to 95 +/- 25 bpm [P less than 0.05]), associated with norepinephrine increase from 402 +/- 243 to 744 +/- 364 pg/ml (P less than 0.001). In CHF the cardiac index increase was caused by a stroke volume index increase (23 +/- 4 to 33 +/- 9 ml/min; P less than 0.01), with no significant change in heart rate or norepinephrine. Thus nicardipine, by means of calcium channel antagonism, induced reversal of vasoconstriction. Differences in the cardiac response identify the importance of characterizing the pathophysiologic status of cardiac impairment to more accurately interpret pharmacologic interventions.

Adult↗

PubMed2005

Simulation in cardiology and cardiothoracic and vascular surgery.

Cardiologists and cardiac surgeons are rapidly embracing the use of realistic patient simulators and virtual reality devices to allow mastery of complex techniques, planning of complicated procedures, crisis management of infrequently seen diseases and complications, and development of medical team work. Simulation can certainly be used for these purposes in surgical education but provides only the ;;tip of the iceberg'' of the knowledge needed by the competent cardiothoracic, vascular, or general surgeon. Is simulation really the way to learn how to perform actual surgical procedures? This review will describe available surgical simulation technology, and define some of the problems to be solved for validation and general acceptance.

Anesthesiology↗