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Biomedical subjects

E Raposio

Publications and source records attributed to E Raposio.

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

Cleft lip: a histochemical and ultrastructural analysis of lip muscles.

AIMS: In order to evaluate the pathogenesis of cleft-lip in relation to both the anatomical and structural anomalies of the mesenchymal tissues, the authors concluded that the presence of structural anomalies in the examined tissues could not explain the malformation, but might be a consequence of it. Delayed muscular development, asymmetrical distribution of the muscular fibres and their anomalous insertion suggest that the anatomical/functional loss clinically detectable in the orbicular muscle could be the result of a perinatal dysmorphological process rather than of a simple mesenchymal hypoplasia. METHODS: Schendel et al. suggested that a metabolic defect in the mitochondrial function could cause a deficiency in cell migration and proliferation responsible for the malformation in question. To establish whether the pathogenesis of the cleft-lip is associated with an alteration in mitochondrial functionality, eight patients affected by unilateral cleft-lip were subjected to a biopsy of the orbicular muscle during the course of reparative surgery. RESULTS: The results obtained showed: 1) a great variation in the size of muscle fibres; 2) the absence of ragged red fibres; 3) a normal oxidative function in the muscle fibres examined; 4) the absence of typologically significant groupings positive for myofibral ATPases. Furthermore, the morphology of the mitochondria was preserved in all cases and neither inclusions nor morphological or volumetric changes were detected. CONCLUSIONS: This preliminary data did not confirm the constant presence of mitochondrial pathology responsible for the malformation in question. In our opinion, the growth deficiency of the maxillary segment could be ascribed to the cicatrization of the surgical repair of the cleft-lip.

Adenosine Triphosphatases↗
PubMed1998

Pharmacological enhancement of cutaneous flap survival with topical dimethyl sulphoxide and hydrogen peroxide.

The present study was designed to investigate, in a rabbit model, the value of topical application of a solution of hydrogen peroxide (H2O2) 8% + dimethyl sulphoxide (DMSO) 50% in order to reduce ischaemic failure in random skin flaps. Two parallel, cephalad-based para-midline random cutaneous flap (10 cm x 2.5 cm) were elevated and resutured in place on the dorsum of 40 New Zealand rabbits. The 80 flaps thus obtained were then randomly divided into one control group and three experimental groups of 20 flaps each. Flaps from the control group (Group A) were topically treated with saline, while flaps from experimental Group B were treated with H2O2 8%, flaps from experimental Group C with DMSO 50%, and flaps from experimental Group D with a solution of 50% DMSO + 8% H2O2. Each solution was topically applied to the flaps, 20 ml three times a day for 7 days, starting in the immediate postoperative period. Transcutaneous oxygen tension (PtcO2) measurements were carried out in all flaps 72 h after flap elevation. The percentage of surviving skin area of each flap was determined by planimetry 7 days after flap elevation. The mean surviving area of the Group A (control) flaps was 71%, the mean surviving area of the Group B (H2O2-treated) flaps was 72%, the mean surviving area of the Group C (DMSO-treated) flaps was 76%, and that of the Group D (DMSO+H2O2-treated) flaps was 92%. While no statistically significant differences were found between the survival rates of both the flaps treated with H2O2 or DMSO alone and that of the control group, the mean surviving rate of the DMSO+H2O2 treated flaps (+20%) was statistically higher than that of the control flaps. Similarly, a statistically significant difference has been found between the mean PtcO2 values of the DMSO+H2O2 flaps and those of the other three groups of flaps.

Animals↗
PubMed1998

Effects of galeotomies on scalp flaps.

The aim of the present study was to evaluate how much a relaxing incision of the galea aponeurotica affects the biomechanical properties of a scalp flap to quantify the surgery-related advantages provided by this procedure. Twenty scalp flaps, created by a reverse-Y incision down to and through the galea aponeurotica together with undermining (in the layer between the galea and the pericranium) to within 1 cm of the external auditory canal were studied. Data were collected by stepwise loading the scalp flaps before and after performing three full-thickness galeotomies lengthwise and parallel to the sagittal scalp incision. The tension/ extension ratio characteristics were computed, and loading curves as well as mean stiffness values were measured. A statistically significant difference (-16.6 g per millimeter) was found between the slope (computed as Young's modulus) of the curves obtained before and after performing the galeotomies. This value corresponded to a mean 40% reduction of the closing tension attained with each galeotomy. In the closing-tension interval 500 g to 1,500 g, the mean gain of length of the flap per galeotomy was 1.67 mm. These data confirm the usefulness of galeotomies for lengthening the scalp flaps and for diminishing the tension on wound margins when closing scalp defects.

Adult↗
PubMed1998

Undermining of the scalp: quantitative effects.

The aim of the present study was to evaluate to what extent undermining affects the closing-tension of scalp defects to quantify the surgery-related benefits provided by this procedure. Data were collected by stepwise loading in 10 patients, 20 scalp flaps (obtained by a reversed Y scalp incision), and three different degrees of subgaleal undermining (1, 5, and 15 cm). The obtained data confirmed the value of undermining to diminish the tension on wound margins when closing a scalp defect. There was a progressive decrease in tension required to advance the wound edge when the amount of undermining was sequentially increased. Most of this reduction occurred with the 5-cm undermining, although statistically the 15-cm undermining also resulted in a significant decrease in the tension required to close the defect. Mean 83.3- and 92.2-percent reductions of the closing tension were obtained with 5 cm and 15 cm of undermining, respectively, compared with that achieved by the 1-cm undermining with the same width of defect.

Adult↗
PubMed1998

Follicular bisection in hair transplantation surgery: an in vitro model.

The aim of this study was to evaluate, in an in vitro model, the survival and growth rates of transversely sectioned human hair follicles to assess experimentally the soundness of this approach as a future possible method for "duplicating" available donor hair grafts in hair transplantation procedures. A total of 300 human anagen hair follicles was obtained from 10 healthy male patients. Follicles were thus randomly assigned to one of the following groups: group A (control; n = 100 follicles), cultured intact as dissected, and group B (experimental; n = 200 follicles), transversely transected, parallel to the epidermal surface and immediately below the bulge area, to obtain 200 lower-half follicles and 200 upper-half follicles. Isolated hair follicles from both groups were maintained in culture for 10 days. The length of each follicle was measured immediately following isolation and at the end of the 10-day culture period. No statistically significant differences were found between the growth rate of intact follicles (mean 10-day growth rate = 2.71 mm) and of lower-half follicles (mean 10-day growth-rate = 2.64 mm), whereas a statistically significant difference was found between the growth rate of follicles from the two above-mentioned groups and the growth rate of the "upper-half" follicles (mean 10-day growth rate = 1.07 mm). Histologic analysis demonstrated that both intact and lower-half follicles maintained a normal histologic appearance, whereas in upper-half follicle sections we invariably detected a region of intense cell proliferation, reminiscent of a regenerated follicular papilla, surrounding the lowermost part of the follicle. In our opinion, the reported in vitro survival rate of transected human hair follicles might represent an interesting starting point in striving to augment the number of donor hairs available during a hair transplantation procedure.

Adult↗
PubMed1998

Mitochondrial activity of orbicularis oris muscle in unilateral cleft lip patients.

To better evaluate the role of a possible mitochondrial alteration in the pathogenesis of cleft lip, we obtained and examined 38 orbicularis oris muscle specimens taken from the cleft margin of both cleft and noncleft sides of 10 unilateral cleft lip infants at the time of primary closure. Part of each sample was frozen in liquid nitrogen/cooled isopentane, while the remainder was fixed in 2.5% glutaraldehyde, postfixed in osmium tetroxide, and embedded in Araldyte resin. Ten-micrometer-thick sections were obtained from the frozen samples and stained for histologic (Gomori trichrome) and histochemical (adenosine triphosphatase, nicotinamide adenine dinucleotide-tetrazolium reductase, cytochrome c-oxidase, succinate dehydrogenase) techniques. Ultra-thin sections (70 to 100 nm) of the resin-embedded specimens were stained with uranyl acetate and lead cytrate and were examined with a Zeiss 109 transmission electron microscope operating at 80 kV. Muscular fiber-type ratio was found to be 19.2 percent type 1 and 80.8 percent type 2 fibers on the cleft side and 26.3 percent type 1 and 73.7 percent type 2 fibers on the noncleft side. We detected aspecific structural alterations, such as variations in the fiber size without fiber group atrophy or fiber-type grouping with the ATPase reaction, in all biopsies. Although Gomori trichrome revealed a dark staining and red granularity of the fibers, suggesting an increase in mitochondria activity, no ragged-red fibers or cytochrome c-oxidase-negative/succinate dehydrogenase-positive fibers were found. At the ultrastructural level, the mitochondrial morphology was always preserved, without inclusions or variations in size and/or shape. On the other hand, we invariably noticed an increase of the number of mitochondria, associated with abnormal glycogen deposits, in some areas of every specimen. Both of these two latter findings were regularly localized at the periphery of the sarcolemma, resembling the so-called lobulated fibers, an aspecific sign of muscular flogosis. Our findings, although excluding an inherent metabolic myopathy of orbicularis oris muscle in unilateral cleft lip patients, evinced both an increased oxidative metabolism and a generic inflammatory condition of that muscle, the nature of which must still be defined.

Adenosine Triphosphatases↗
PubMed1998

Endoscopic transthoracic dorsal sympathectomy for the treatment of upper extremity hyperhidrosis: a new minimally invasive approach.

Palmar and axillary hyperhidrosis are best treated surgically by endoscopic transthoracic upper dorsal sympathectomy. At present, this methodology relies on (at least) double trocar insertion (per side), carbon dioxide insufflation, or both. We present a new minimally invasive endoscopic transthoracic technique, performed by a single-entry specifically modified thoracoscope and without the need for carbon dioxide insufflation, with the aim to reduce the drawbacks associated with the above-mentioned, currently adopted endoscopic technique. In our opinion, this "single-entry" technique, compared with the other reported approaches, should theoretically minimize any damage to the intercostal neurovascular bundle, while avoiding the complications related to carbon dioxide insufflation.

Adolescent↗
PubMed1998

Anchoring galeal flaps for scalp reduction procedures.

This article describes an operative technique, based on the use of three anchoring galeal flaps, aimed at reducing the percentage of "stretch-back" that occurs after performing scalp reduction procedures. In 12 male patients undergoing a midline scalp reduction procedure, three rectangular (2 x 3 cm) galeal flaps in direct continuity with the longitudinal margin of the left scalp flap were sutured individually to the galeal undersurface of the right scalp flap to draw the two scalp flaps toward the midline of the scalp and to relieve the wound margins of closing tension. Tattoo marks were placed on the patient's scalp at the level of the vertical lines drawn through the external auditory meatuses (A1-A2) and 6 cm more posterior (B1-B2) to measure the movement and stretching of the scalp. The results were compared with those obtained from a control group of 13 male patients who underwent the same surgical procedure but without the use of the anchoring galeal flaps. Mean stretch-back (as measured 4 weeks postoperatively) at level A1-A2 was 8.3 mm in the control group and 1.6 mm in the experimental group. The mean stretch-back at level B1-B2 was 7.7 mm in the control group and 0.9 mm in the experimental group. A statistically significant difference (p < 0.005) was found between data from the control and experimental groups regarding the above-reported stretch-back values at both levels. The use of the described galeal flaps allowed us to obtain an 80.93-percent and an 88.09-percent stretch-back reduction at levels A1-A2 and B1-B2, respectively, 1 month postoperatively.

Adult↗
PubMed1998

Power boosting the grafts in hair transplantation surgery. Evaluation of a new storage medium.

BACKGROUND: When performing hair transplantation procedures, it is of the foremost importance to try to obtain the maximum survival rate possible of transplanted micrografts. OBJECTIVE: Aim of this study was to evaluate, in an in vitro model, the effects of preserving micrografts, for five hours, in an enriched storage medium in order to enhance the survival rate of hair micrografts. METHODS: A total of 200 human anagen hair follicles was obtained from ten male patients. Follicles were thus randomly assigned to one of the following group: Group A (control; n = 100 follicles), preserved for five hours in saline, and Group B (experimental; n = 100 follicles), preserved for five hours in a storage medium, containing adenosine triphosphate-magnesium chloride and deferoxamine mesylate. Isolated hair follicles from both Groups were then cultured for 10 days. RESULTS: A statistically significant difference was found between the survival rate of experimental (98%) and control follicles (87%). CONCLUSION: In our opinion, a "metabolic preconditioning" of micrografts by means of storing them for 5 hours in the described medium may be of some utility in augmenting the survival rate of hair grafts when performing hair transplantation surgery.

Adenosine Triphosphate↗
PubMed1997

Recent results in color compositing of three-parameter magnetic resonance scans as a preoperative aid to the management of upper limb sarcomas.

We report on improved image quality and some recent clinical results with volume-rendered, color composite, multiparameter, magnetic resonance (MR) datasets and their color histograms. In a previous article we demonstrated the major components of an interactive visualization environment for multiparameter T1-, T2-, PD-weighted MR volume datasets. These are compositing of the three parametric volumes, color volume rendering of the resulting composite, interactive segmentation of the tissues based on color cluster statistics derived from display of the three-dimensional (3D) histogram, and head-tracking stereo display. We herein review the system design and describe improvements to the quality of the color volume rendering, in the display of the 3D color histogram data, and in the specification of the volume renderer's opacity function. Finally, we report on some recent clinical results using our system.

Arm↗
PubMed1997

Tension and flap advancement in the human scalp.

The aim of the present study was to evaluate quantitatively the change in stiffness of scalp flaps determined by increased loads of tension. Data were collected by stepwise loading 20 scalp flaps, created by a reversed-Y incision down to and through the galea aponeurotica together with undermining. In the layer between the galea and the pericranium, to within 1 cm of the external auditory canal. The biomechanical properties of the tested scalp flaps were significantly influenced by increased extents of tension. The tissue's stress response to displacement was visualized as a three-phase characteristic. Initially linear (indicative load range, 0 to 500 g), the scalp's compliance gradually reduced (indicative load range, 500 to 1,500 g) and eventually demonstrated an exponential stress/strain characteristic of rapidly increasing stiffness (indicative load range, 1,500 to 5,000 g). The Young's modulus, E, of the stress/strain curve was found to be equal to 49.2 g per millimeter. The obtained data suggest that a reasonable approach should consist of closing a scalp defect within the tension range of 500 to 1,500 g. This will take full advantage of the plasticity of the scalp flap. The gain obtained with a closing tension above this range would be minimal, with a presumably increased complication rate.

Adult↗
PubMed1997

Computer-aided preoperative planning of tissue expansion.

The aim of this paper is to introduce a computer program developed to provide objective, quantitative data useful to ensure proper expander selection when having to use a rectangular tissue expander. The program is developed to calculate the volume of a rectangular tissue expander to obtain the exact amount of yield needed to allow for reconstruction of a determined defect. The only data to be supplied are the length and the width of the defect to be reconstructed. In our opinion, although its use is not aimed at replacing clinical judgment based on experience and careful observation, this program may be considered a simple and useful adjunct for the inexperienced surgeon (or the occasional operator) planning to use a rectangular tissue expander.

Decision Support Techniques↗
PubMed1997

Minigraft preparation in surgical hair replacement.

A 38-year-old man with Norwood type V male pattern baldness underwent hair restoration surgery using a new technique aimed to minimise the time spent on cutting minigrafts by using a multibladed knife. A total of 600 minigrafts were harvested from the occipital region, prepared, and inserted into the bald area. This method significantly enhances the rate of minigraft preparation during hair transplantation procedures, as dividing minigrafts from hair-bearing strips of scalp using a multibladed knife simplifies the whole cutting session. Furthermore, grafts prepared with the multibladed scalpel are more regular in size than those obtained with the traditional technique.

Adult↗
PubMed1997

Simulation of soft-tissue tumor excisions: a multimodal interactive approach.

Total 3-D reconstruction of the tumor size, shape, and relations with surrounding structures using CT, MRI, sonography, and angiography images can make simulated radical resection of soft-tissue sarcomas possible, thus sparing normal tissues. With our approach, starting from three MR images for a given patient, a new single image representation of all three parameters is generated by using two different techniques on a workstation in a standard UNIX and X-11 environment. The first one is a transformation linking together the MR parameters and the RGB (red, green, blue) color components. The second one is an unsupervised segmentation method based on a number of neural and fuzzy models. We can dinamically render and update a stereo display using field sequential presentation of left and right eye views on the monitor, with Cristal Eyes LCD shutter eyewear (StereoGraphics Inc., San Rafael, CA) to view it. As 3D locating tool, a 3D locating control system based on low-frequency magnetic fields (Polhemus Fastrak) has been chosen. Simulations of soft-tissues excisions may be performed in this interactive environment with augmented-reality modalities. All this, in our experience, has greatly facilitated the simulation of soft-tissue sarcoma excisions.

Artificial Intelligence↗
PubMed1997

An "augmented-reality" aid for plastic and reconstructive surgeons.

Starting from MR and CT images for a given patient, a new single image representation of all parameters has been generated by using false-color techniques in a standard UNIX and X-11 environment. A transformation linking together the MR, CT parameters and the RGB (red, green, blue) color components has been used. Moreover an unsupervised segmentation method based on a number of neural and fuzzy models may directly produce segmented image volumes. Each image of the various sequences has been interactively displayed by using a specifically designed application. The resulting images have been displayed on a stereo monitor allowing the three-dimensional rendering of visual data through LCD shuttered glasses. Moreover, a 3-D control system based on low frequency magnetic fields has been used, while a bandheld Polhemus stylus could be used as an electronic knife for dissecting the 3-D data set and for defining flaps and grafts. Bone or soft-tissue contour can be analyzed, and sections can be removed from the model to allow a view of the underlying structures. Flaps and grafts obtained utilizing the above-reported techniques can be fitted exactly, without repeated removal and recarving. Nuances of depth, tapering, and arc are carved directly into the bone, while chances of asymmetry are markedly diminished. In this way, moreover, anesthetic times are reduced by more efficient utilization of operative time, which usually offsets the increased cost of imaging.

Artificial Intelligence↗