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Biomedical subjects

L A Ferrara

Publications and source records attributed to L A Ferrara.

At least 19 recordsLinked to original sources
PubMed2006

Improvement of cardiovascular risk profile in an elderly population of low social level: the ICON (Improving Cardiovascular risk profile in Older Neapolitans) study.

Older age and low socio-economic conditions are associated with poor control of cardiovascular risk factors (RFs). We assessed the prevalence and awareness of cardiovascular RFs in 503 elderly outpatients of low social status attending two public Internal Medicine clinics in Naples, and studied the interaction of education and employment level with risk profile. The therapeutic intervention was oriented to improve patients' motivation through a positive patient-physician relationship, in keeping with the current guidelines for hypertension. The effect of treatment was evaluated by comparing retrospectively the level of cardiovascular RFs at baseline and at the last follow-up examination performed within 31 October 2005. Only 33.3% of patients (age=68+/-6 years) had attended primary school. Overall (current or previous) employment level was also low. Obesity, hypertension and dyslipidaemia were present in most patients, diabetes in 17.3% of them. In all 8.0% of hypertensives, 16.1% of diabetics and 24.7% of dyslipidaemiacs were unaware of their diseases. Cardiovascular risk profile was worse at lower educational and employment levels. Odds ratios for the metabolic syndrome were 0.28 (95% confidence interval (CI)=0.15-0.52) and 0.35 (0.20-0.62) in the most qualified of three education and employment groups, respectively, compared to the lowest ones. The level of all cardiovascular RFs was effectively reduced during treatment. Control rate of most RFs improved significantly (for hypertension, from 12.8 to 36.5%, P<0.001). These patients had a high prevalence of cardiovascular RFs, which correlated with their educational and work activity levels. Awareness of their health status was unsatisfactory. Treatment, specifically addressing patient-physician relationship, favourably affected cardiovascular risk profile.

Aged↗
PubMed2006

Effects of different dietary protein intakes on body composition and vascular reactivity.

OBJECTIVE: To assess the effects of a diet rich in protein of animal origin in comparison to one with a protein intake of about 15% of the total daily calories on body composition and arterial function. DESIGN: Randomized prospective study with parallel groups. Body weight (BW), blood pressure (BP), main parameters of carbohydrate and lipid metabolism, body mass composition by bioelectrical impedance analysis, forearm blood flow at rest and in the postischaemic phase by strain gauge plethysmography and flow-mediated dilation of the brachial artery by echography were measured at baseline and after 6 months of the dietary intervention. SUBJECTS: In total, 15 clinically healthy male volunteers, regularly performing a mixed training three times weekly for 90 min. INTERVENTION: The participants were randomly prescribed a diet with high (1.9 g/kg BW) or normal (1.3 g/kg BW) protein content. STATISTICAL ANALYSIS: Differences between means were evaluated by the t-tests for paired or unpaired data and by one way analysis of variance. The strength of correlation between variables was investigated by bivariate Pearson correlation. RESULTS: Serum cholesterol significantly decreased with both diets in comparison to baseline values, whereas BW was slightly but significantly reduced only by the high-protein (HP) diet. No change was detected in BP and the other metabolic parameters. Body mass composition was not significantly modified by either diet. On the other hand, postischaemic flow-mediated dilation of the brachial artery was enhanced by the sole normal protein (NP) diet, whereas no change in the forearm blood flow, both at rest and in the postischaemic phase, was detected. CONCLUSIONS: These preliminary results indicate that HP diet was found to be not useful in increasing the muscle mass in comparison to a NP intake. In contrast to this, the latter diet seems to enhance the endothelial function of the arterial vessels with a more pronounced dilatation of the lumen in response to the increase in blood flow.

Adolescent↗
PubMed2004

Arterial hypertension increases left ventricular mass: role of tight blood pressure control.

In middle-age hypertensives from the Gubbio Population Study, we evaluated the relationship between blood pressure (BP) control over a long time and the prevalence of left ventricular hypertrophy (LVH). A population survey was performed in 1982-1985 and repeated in 1989-1992. During the second survey, subjects in the age range 40-60 years were invited to undergo an M-mode echocardiographic examination. A total of 487 subjects who participated in both surveys are included in the present analysis. Some of them (294) were normotensive (Group 1), 110 were hypertensive but had never taken antihypertensive drugs (Group 2), 47 hypertensives on drugs were in good BP control (Group 3) and 36 hypertensives on drugs had uncontrolled hypertension (Group 4). BP values at the 1989-1992 examination were, respectively, 122/77, 145/86, 124/78 and 153/91 mmHg, while 7 years earlier were 122/77, 133/84, 136/85 and 152/95 mmHg. Despite normal BP levels in Group 3, left ventricular mass index (LVMi, g/m(2.7)) was greater than in normotensives (42.4+/-10, 46.6+/-13, 47.0+/-10, 51.9+/-15 g/m(2.7)). Accordingly, the prevalence of LVH (LVMi >51 g/m(2.7)) was 18, 26.4, 36.7 and 50% in groups 1-4, respectively. The 193 hypertensives were, thereafter, divided according to BP control (ie <140/90 mmHg) on both surveys (1983-1985 and 1989-1992): 27 hypertensives with optimal BP levels on both visits also had a ventricular mass similar to normotensives and significantly lower than the other hypertensives (LVMi 44.6+/-11.6 vs 48.5+/-13.2, P<0.001). In conclusion, these findings indicate that hypertensive patients with BP values at levels similar to those in normotensives for a long period do not increase their left ventricular mass in comparison to subjects with normal BP levels.

Adult↗
PubMed2003

Silicon dermabrasion tools for skin resurfacing applications.

Miniature abrasion tools for potential skin resurfacing applications are created using microelectromechanical systems (MEMS) fabrication technology. The abrading microstructures are formed on silicon wafers by a bulk micromachining process based on isotropic xenon difluoride etching. The micromachined abraders (microdermabraders) are packaged and applied to human cadaveric skin to assess abrasion quality. Plastic (acrylic) microreplicated structures, non-coated and aluminum-coated versions, are also used in a similar fashion. Non-textured silicon and plastic samples are used as study controls. Dermabraded and intact skin regions are analyzed qualitatively and quantitatively by light microscopy, image processing techniques, and histology. The microdermabraders exhibit a cleaner, more uniform abrading pattern on the cadaveric skin compared to the plastic microreplicated structures. Furthermore, the microdermabraders provide a consistently uniform cut through the epidermal layer, leaving little debris and minimal pitting. In contrast, the plastic microreplicated structures exhibit non-uniform abrading patterns and leave behind more debris and eccentric pits. The results suggest micromachined dermabraders can successfully abrade fine dermatological flaws in human skin.

Cadaver↗
PubMed2002

Serum cholesterol affects blood pressure regulation.

A close relationship between abnormalities of the lipid metabolism and arterial hypertension has been observed in several epidemiological studies. The aim of the present study was to investigate whether serum cholesterol might affect blood pressure (BP) levels at rest, during ambulatory monitoring or during sympathetic stimulation-independently of other variables such as body weight or serum insulin-thus influencing the outcome of hypertensive complications. Seventy-three patients with sustained newly-discovered and never-treated hypertension were divided into tertiles according to their serum cholesterol levels and their resting BP, 24-h BP and BP during isometric exercise (handgrip) were compared. Cardiac mass and carotid wall thickness were measured by echographic technique. The results were that tertiles were similar for body weight, blood glucose and serum insulin, but different for serum cholesterol and triglycerides. BP at rest and during 24-h monitoring was similar in the three groups, whilst a significant difference was detected during sympathetic stimulation by handgrip, with systolic and diastolic BP increasing by 16/12, 28/19 and 30/23 mm Hg (P < 0.01) in lower, medium and higher tertiles, respectively. Intima-media layer of the carotid arteries was also significantly thickened in the groups with higher cholesterol levels (0.54 +/- 0.07, 0.67 +/- 0.14, 0.68 +/- 0.15, P < 0.05). These data support the conclusion that even in patients with recently discovered hypertension, cholesterol levels may influence the BP response to adrenergic stimulation as well as the outcome of target organ disease.

Adolescent↗
PubMed2002

Clinic and ambulatory pulse pressure segregate a cluster of cardiovascular risk factors.

Office pulse pressure (PP) has been found to be independently associated with cardiovascular morbidity and mortality. While there is evidence that 24 h blood pressure (BP) is a better marker of the cardiovascular complications of hypertension than office BP, this information is still lacking in regard to PP. The aim of the present study was, therefore, to evaluate possible differences between office and 24 h PP in their relationship with cardiovascular risk profile. This cross-sectional study was performed in a group of 175 (104 M, 71 F) hypertensives (43 never treated before the study) free of clinical evidence of target organ disease. BP was measured at rest and during 24 h monitoring; cardiac structure and function was studied by ultrasounds; biochemical analyses were performed to evaluate some parameters of lipid and carbohydrate metabolism. Patients were divided into tertiles of office PP and of 24 h PP. Those in the highest tertile of PP had a significantly higher office and 24 h systolic BP along with a reduction in peripheral insulin sensitivity. Regarding cardiac structure and function, a significantly higher prevalence of concentric left ventricular hypertrophy (23 vs 55%; P=0.05) and an initial impairment of diastolic function with increase of the A wave was detected in hypertensives with higher PP. No difference between office and 24 h PP in detecting patients at higher cardiovascular risk was observed. In conclusion, office and 24 h pulse pressures were both able to segregate patients with a cluster of cardiovascular risk factors.

Adult↗
PubMed2001

Biomechanics of bone fusion.

Bone fusion can be achieved by one or more of three methods: in situ, onlay, and interbody fusion. Interbody implants provide the spine with the ability to bear an axial load. They function optimally when placed along the neutral axis and produce little, if any, significant bending moment. Interbody implants may be comprised of bone, non-bone materials such as acrylic, or a combination of both such as in interbody cages. In this report the authors' goal is to provide some insight into the theoretical, as well as practical, biomechanical factors that influence bone fusion, focusing on interbody implants. They review the concept of stress shielding and its impact on fusion. With the attendant biomechanical nuances of the different regions of the spine, they discuss region-specific strategies involved in successful fusion. Finally, they review intraoperative techniques that will improve the chance of achieving a successful arthrodesis.

Animals↗
PubMed2001

Quantitative changes in spinal canal dimensions using interbody distraction for spondylolisthesis.

STUDY DESIGN: An experimental study was performed using cadaveric lumbar spines to evaluate the effect of anteriorly or laterally placed interbody distraction implants on the alteration of spinal canal and neuroforaminal dimensions. OBJECTIVES: To quantify changes in the spinal canal and neuroforaminal dimensions using interbody fusion devices inserted at various configurations in cadaveric lumbar spines exhibiting degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Although several clinical studies have demonstrated successful treatment of degenerative spondylolisthesis with anterior interbody fusion, no study has shown the role of interbody distraction in improving lumbar spinal canal and foraminal stenosis. METHODS: Five fresh cadaver lumbar spines exhibiting a degenerative spondylolisthesis or retrospondylolisthesis were used for the study. Computed tomography scans of each specimen and a silicon mold of the left intervertebral foramens were repeated in a consistent manner after pure compressive load (150 lb) was applied to simulate physiologic load (intact case), after two BAK (Sulzer SpineTech Inc., Minneapolis, MN) distraction plugs were anteriorly inserted into the intervertebral disc space (anterior distraction cases), and after one long BAK cage was laterally inserted from the left side (lateral distraction case). The cross-sectional area of the spinal canal was measured from computed tomography images using National Institutes of Health image software (Bethesda, MD). The spinal canal volume was calculated using the cross-sectional area and total scan thickness. Left intervertebral foraminal volumes were calculated from the weight of the silicon mold injected into the foramen. Descriptive statistics and a Student's t test were used to detect statistical differences in the spinal canal and neuroforaminal volumes before and after interbody distraction. RESULTS: The cross-sectional canal area was significantly increased after anterior distraction (35.11%) and lateral distraction (33.14%). The spinal canal volume was markedly increased with anterior distraction (19.92%) and lateral distraction (21.96%). Left foraminal volume was also enhanced by 40.25% for anterior distraction and 41.03% for lateral distraction. CONCLUSIONS: Interbody distraction either by anteriorly inserted plugs or laterally inserted threaded cagescan immediately improve the narrowed canal area and increase spinal canal, as well as foraminal volume for lumbar degenerative spondylolisthesis or retro- spondylolisthesis.

Anthropometry↗
PubMed2001

Structural features and thickness of the vertebral cortex in the thoracolumbar spine.

STUDY DESIGN: The thickness and structure of the vertebral body cortex were examined from sections of human cadaveric vertebrae. OBJECTIVES: The objectives were to identify the principal structural features of the cortex, to directly measure the minimum and maximum thicknesses of the cortex in the thoracolumbar spine, and to compare regional variations in the structure of the cortex. SUMMARY OF BACKGROUND DATA: The thickness of the vertebral cortical shell contributes to the compressive strength of the vertebral body. There is little consensus concerning the thickness and morphology of vertebral shell and endplate along the spine in existing data. METHODS: Human T1, T5, T9, L1, and L5 vertebral bodies (mean age 70.4 years) from 20 cadaveric spines were sectioned and photographed. The minimum and maximum cortical thickness of the shells and endplates in the midsagittal plane were measured from magnified images. RESULTS: The anterior shell thickness was significantly greater than the posterior shell and both endplates. Endplate thickness was greatest in the lower lumbar vertebrae. There was a significant decrease in cortex thickness over the central portion of endplates and shells, with a mean minimum thickness of 0.40 mm and a mean maximum thickness of 0.86 mm, with an overall mean of 0.64 +/- 0.41 mm. Increased porosity was also observed along the central regions of the cortical shells. In the lower thoracic and lumbar spine, a double-layered endplate structure was observed. CONCLUSIONS: Invasive techniques provide the only means to directly resolve the thickness and distribution of bone in the vertebral cortex. The cortex thickness and structure varies along the endplates and the anterior and posterior surfaces of the vertebral body. The implications of the so called double-layered endplate structure are unknown, but indicate the need for further study.

Aged↗
PubMed2001

Microelectromechanical systems and neurosurgery: a new era in a new millennium.

MICROMACHINES AND MICROELECTROMECHANICAL SYSTEMS (MEMS) are terms that are new to neurosurgeons but certain to become "household terms" in neurosurgery in the near future. These new terms serve as an introduction to a new world of sensors, actuators, and "smart systems" that will change the ways in which neurosurgeons interact with their environment. Through the use of microelectronics and micromachining technologies, MEMS will allow neurosurgeons to perform familiar tasks with greater precision, perform tasks that previously were not done at all, and monitor physiological and biochemical parameters more accurately and with greater safety. This review provides the information necessary to understand the fundamental concepts of MEMS and their application to the neurosurgical arena. It defines the relevant terms and describes the history behind the "micromachine revolution," the capabilities and limitations of MEMS technology, and how this revolution is germane to neurosurgery and to neurosurgeons.

Artificial Intelligence↗
PubMed2001

Effects of hole preparation on screw pullout resistance and insertional torque: a biomechanical study.

OBJECT: The authors conducted a study to assess the effect of a pilot hole preparation on screw pullout resistance and screw insertional torque. METHODS: Three different screws were tested: cancellous lateral mass screws, cortical lateral mass screws, and pedicle screws. Synthetic bone blocks were used as the host material. Each screw group was separated into two subgroups. The first subgroup of screws was inserted into the test material following pilot hole preparation. Pilot holes were prepared; a drill bit diameter size smaller than the core diameter of the screws was used. The second group of screws was inserted into the test material without pilot hole preparation (a 3- or 4-mm hole drilled for entrance site preparation only). The insertional torque was measured as the screw was advanced into the material. The screws were axially extracted from the host material at a constant speed of 2.5 mm/minute. The pullout resistances and insertional torques for the pilot hole and the nonpilot hole groups were then statistically compared. The authors found that preparation of a pilot hole caused a significant decrease in the insertional torque. The screws inserted without a pilot hole showed greater pullout resistances compared with those inserted following a pilot hole preparation; however, there was no statistically significant difference. CONCLUSIONS: The optimum screw insertion technique may involve drilling a short pilot hole and using a drill bit with a smaller diameter than the screw core diameter to increase bone-screw purchase. This applies to cancellous and cortical lateral mass screws as well as pedicle screws.

Biomechanical Phenomena↗
PubMed2001

Effects of cervical spine posture on axial load bearing ability: a biomechanical study.

OBJECT: The authors conducted a study to assess the effects of cervical posture on the loadbearing ability of the cervical spine. METHODS: Twelve cervical spine specimens obtained in 12 adult sheep were tested. The specimens were randomly separated into two groups. In Group I the specimens were fixed in a lordotic posture, and in Group II they were fixed in a straight posture. Axial compressive loads were applied at a constant rate of 5 cm/minute. Load-to-failure, time-to-failure, piston displacement at failure, and failure modes were recorded. Statistical analyses were performed to detect differences between the groups. There was no significant difference in load-to-failure values between the two groups. However, the time-to-failure and the piston displacement values for the straight spines were significantly less than those for the lordotic spines. Additionally, the straight spines failed predominantly through ventral elements, whereas the lordotic spines predominantly failed dorsally. CONCLUSIONS: It is concluded that a loss of a lordosis increases the risk of injury to the cervical spine following axial loading.

Animals↗
PubMed2001

Insulin resistance, ventricular mass and function in normoglycaemic hypertensives.

BACKGROUND AND AIM: To investigate the possible relationship between insulin sensitivity and the main non-invasively determined parameters of left ventricular structure and function in an early phase of hypertensive disease. METHODS AND RESULTS: We studied a group of 60 patients with previously untreated primary arterial hypertension of recent onset. Insulin sensitivity was evaluated by means of homeostasis model assessment (HOMA), and cardiac structure and function by means of ultrasonography. The patients were subsequently divided on the basis of HOMA tertiles and the between-group differences were statistically evaluated using one-way analysis of variance. No difference was found in the main demographic parameters, but high-density lipoprotein (HDL)-cholesterol was significantly higher (1.43 +/- 0.4, 1.16 +/- 0.2, 1.16 +/- 0.2 mmol/L; p < 0.05) and total triglycerides significantly lower (0.94 +/- 0.3, 1.41 +/- 0.8, 1.54 +/- 0.7 mmol/L; p < 0.05) in the first tertile. In relation to the non-invasive parameters of diastolic function, the E wave was significantly reduced in the third tertile (0.64 +/- 0.1, 0.63 +/- 0.1, 0.52 +/- 0.1 m/s; p < 0.05), with a concomitant significant increase in AFF (0.51 +/- 0.03, 0.51 +/- 0.06, 0.56 +/- 0.03; p < 0.05). The E wave (r = 0.326, p < 0.05), E/A wave ratio (r = -0.277, p < 0.05) and AFF (r = 0.432, p < 0.001) were significantly related to HOMA, regardless of age, body mass index, heart rate, left ventricular mass and blood pressure. CONCLUSIONS: Our results indicate that hypertensive patients in the third HOMA tertile (i.e. those with reduced insulin sensitivity) have early diastolic left ventricular abnormalities.

Adolescent↗
PubMed2000

Olive oil and reduced need for antihypertensive medications.

BACKGROUND: The blood pressure (BP) effects of changing the total fat intake and saturated-unsaturated fat ratio are still controversial, despite evidence that saturated fat-enriched diets are associated with higher BP levels. This double-blind, randomized crossover study evaluated a possible difference between antihypertensive effects of monounsaturated (MUFA) (extra-virgin olive oil) and polyunsaturated fatty acids (PUFA) (sunflower oil). METHODS: Twenty-three hypertensive patients were assigned randomly to MUFA or PUFA diet for 6 months and then crossed over to the other diet; effects were evaluated on the basis of daily antihypertensives needed. RESULTS: Diets high in MUFA and PUFA differed from the habitual diet for reduced total and saturated fats, whereas they differed from each other for MUFA (17.2% vs 10.5%) and PUFA content (3.8% vs 10.5%). Resting BP was significantly lower (P = .05 for systolic BP; P = .01 for diastolic BP) at the end of the MUFA diet compared with the PUFA diet. Blood pressure responses during sympathetic stimulation with the cold pressor test and isometric exercise were similar. Daily drug dosage was significantly reduced during the MUFA but not the PUFA diet (-48% vs - 4%, P<.005). All patients receiving the PUFA diet required antihypertensive treatment, whereas 8 of those receiving the MUFA diet needed no drug therapy. CONCLUSIONS: A slight reduction in saturated fat intake, along with the use of extra-virgin olive oil, markedly lowers daily antihypertensive dosage requirement, possibly through enhanced nitric oxide levels stimulated by polyphenols.

Adult↗