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J Medina

Publications and source records attributed to J Medina.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Progressive bone lengthening of the hand in congenital malformations. 41 cases].

PURPOSE OF THE STUDY: We retrospectively reviewed the experience of two Hand Units with progressive bone distraction lengthening, collecting 41 cases of hand skeleton lengthening for congenital malformations. MATERIAL AND METHODS: The Ilizarov callostasis method was used in 31 cases and in 10 cases bone union was reestablished at a second stage with an iliac graft (2 cases), vascularized metacarpal bone graft (one case), and vascularized (one case) or nonvascularized (3 cases) toe epiphysis. In the last three cases of index lengthening, the distal part was translocated to the tip of the third, deepening at the same stage the first web. The most frequently treated malformation was symbrachydactyly (22 cases). RESULTS: Mean lengthening was 2.3 cm (0.9 to 3.5) with a mean treatment duration of 3.8 months (1.5 - 8.2). The "lengthening index" was 0.59. There was a significant difference between phalanx and metacarpal lengthening, but the amount of lengthening or treatment duration were not affected by technique (Ilizarov vs bone grafting) or age. The complication rate was 32%. There were two complete failures, one extensor tendon tear, 3 pin tract infections (one requiring interruption of the lengthening), 2 cases of relevant pain, 2 delayed unions, 2 angulations and 1 callus fracture, 1 metacarpophalangeal dislocation and 1 joint stiffness. DISCUSSION: Despite advances in micorsurgical toe transfer, there are still indications for bone lengthening in congenital malformations. The apparent simplicity of the technique can mask a certain number of complications, emphasizing the need for surgical experience. Progressive bone lengthening in congenital deformity has the advantage of preserving sensitivity and avoiding bone resorption. Callostasis does not increase the duration of treatment compared to bone graft.

Adolescent↗
PubMed2000

Regulation of absorption and ABC1-mediated efflux of cholesterol by RXR heterodimers.

Several nuclear hormone receptors involved in lipid metabolism form obligate heterodimers with retinoid X receptors (RXRs) and are activated by RXR agonists such as rexinoids. Animals treated with rexinoids exhibited marked changes in cholesterol balance, including inhibition of cholesterol absorption and repressed bile acid synthesis. Studies with receptor-selective agonists revealed that oxysterol receptors (LXRs) and the bile acid receptor (FXR) are the RXR heterodimeric partners that mediate these effects by regulating expression of the reverse cholesterol transporter, ABC1, and the rate-limiting enzyme of bile acid synthesis, CYP7A1, respectively. Thus, these RXR heterodimers serve as key regulators of cholesterol homeostasis by governing reverse cholesterol transport from peripheral tissues, bile acid synthesis in liver, and cholesterol absorption in intestine.

ATP Binding Cassette Transporter 1↗
PubMed2000

Premedication with EMLA cream for ambultory surgery in children.

Objectives: The objective of this study was to confirm the ability of EMLA(R) cream (Eutectic Mixture of Local Anaesthetics, Astra, Sweden) to provide effective dermal analgesia after topical application on the skin of the dorsum of the hand 1 h before venous cannulation for anaesthetic induction. Material and Methods: Prospective, randomized, double blind study. We included 100 children, ASA I-III, distributed into three groups: Group EMLA (E, n=34), Placebo (P, n=33) and Control (C, n=33). Results: The EMLA group of patients (E) refered an evaluation of pain (visual analogical scale (mean=2.34+/-2.41), significantly smaller than the other groups (Placebo=5.54+/-3.40, Control=6.03+/-2.77). Conclusion: EMLA cream, when topically applied 1 h before venous cannulation, provides effective dermal analgesia for venous cannulation. No general or local adverse reactions were observed.

Journal Article↗
PubMed2000

Strategies to antagonise the cyclosporine A-induced proliferation of human pulmonary artery smooth muscle cells: anti-endothelin-1 antibodies, verapamil, and octreotide.

The present study investigated the mechanisms mediating the actions of the immunosuppressive drug cyclosporine A (CsA) on human pulmonary artery smooth muscle cell (PASMC) proliferation. The new hydroxyethyl derivative of D-serine(8)-cyclosporine, SDZ IMM 125, was used for comparison. CsA-induced proliferation was determined by incorporation of [(3)H]thymidine ([(3)H]Thy). CsA in the concentration range between 0.1 nM and 0.1 microM induced a concentration-dependent increase in proliferation after 24, 48, and 72 hr of incubation. Higher CsA concentrations were cytotoxic. When proliferation experiments were performed in the presence of a monoclonal antibody against endothelin-1 (ET-1), CsA-induced proliferation was totally inhibited. No inhibition occurred in the presence of the same antibody when heat-inactivated or a non-specific monoclonal antibody. In parallel, CsA increased the production of ET-1, as determined by radioimmunoassay. Incubation of PASMCs with ET-1 at the concentration range at which the latter was released by CsA induced cell proliferation. The somatostatin derivative Sandostatin (SDT; octreotide), which is an inhibitor of the growth of smooth muscle cells as well as a potent inhibitor of ET-1 secretion, inhibited both the CsA-induced ET-1 release and the increase in [3H]Thy incorporation by PASMCs. A similar effect was observed for the calcium channel blocker verapamil (VP). SDZ IMM 125 induced weaker effects than CsA in terms of PASMC proliferation and ET-1 secretion. In conclusion, CsA increased the rate of proliferation of PASMCs, while SDZ IMM 125 induced a weaker effect. Anti-ET-1 antibody, VP, and SDT significantly inhibited CsA-induced PASMC proliferation.

Antibodies↗
PubMed2000

Use of human skin equivalent Apligraf for in vitro assessment of cumulative skin irritation potential of topical products.

The main goal of the present study was to investigate the response of the human skin equivalent Apligraf in vitro to the application of irritant substances and its predictivity as a screening tool for cumulative skin irritant potential in humans. Vaseline, calcipotriol, trans-retinoic acid, and sodium lauryl sulfate were applied to Apligraf in vitro for 24 h. Cell viability (lactate dehydrogenase leakage), release and mRNA expression of the proinflammatory cytokines IL-1alpha and IL-8, and morphological changes were assessed. The same products were applied to 30 healthy volunteers in a double-blind, randomized, vehicle-controlled within-subject study. The skin reactions after repeated 24-h applications over 3 weeks under Finn chamber patches were monitored by visual scoring and biophysical methods (trans-epidermal water loss, chromametry, and blood flow). Sodium lauryl sulfate was cytotoxic to Apligraf, and increased the release and expression of cytokines at low (0.2%, 0. 4%), but not at high (0.8%, 1%) concentrations. It induced severe irritancy in vivo. Trans-retinoic acid increased the expression and release of cytokines with no detectable cytotoxicity and showed moderate irritancy in humans. Although calcipotriol did neither affect cell viability nor the production of cytokines, it induced morphological signs of irritation and was mildly irritant for healthy volunteers. Vaseline was innocuous in vivo and induced no changes in Apligraf. In conclusion, the cumulative skin irritation potential of the tested products could be predicted with Apligraf in a sensitive and specific manner, by monitoring cytotoxicity, proinflammatory cytokines, and morphological changes.

Double-Blind Method↗
PubMed2000

[Value of a new first web space reconstruction in congenital hand deformities. A study of 54 patients].

INTRODUCTION: Only a few studies are available in the literature on the specific problem of the congenital contracture or absence of the first web in hand deformities, and first web reconstruction. MATERIAL AND METHODS: Sixty-seven first web plasties in 54 patients were retrospectively analyzed: they included 44 cases of classical plasties, i.e., Z-plasty (21 cases); dorsal flap plasty of the index (19 cases), thumb (1 case), or the hand (10 cases), and 16 cases of' pseudo-kite flap. RESULTS: The results were difficult to assess, as the syndromes were dissimilar and the deformities were not comparable (e.g., Apert syndrome versus Poland syndrome). However, it was found that the 'pseudo-kite' technique which was applicable to certain cases resulted in a web extension of 3.2 cm without any deepening. DISCUSSION: No method of classical assessment can be used to comprehensively evaluate the results of first web reconstruction due to the wide variability in clinical characteristics, the lack of patient cooperation in this young age group, the possible MPJ articular thumb instability, and growth factors. Although 4-flap Z-plasty is an adequate technique for non-severe first web deformities, the 'pseudo-kite' flap approach is useful in more severe cases. In 13 cases, a peroperative measurement before and following plasty was made, and a significant increase (205%) in planimetric and stereotactic gain compared to pre-plasty findings was noted. CONCLUSION: It does not seem logical to have a particular preference for a certain approach when considering first web reconstruction in congenital malformations. Each technique has its advantages and disadvantages, depending on patient age, the type of malformation, the state of the thumb, the extent of the first web deformity and the possible presence of scar tissue.

Acrocephalosyndactylia↗
PubMed2000

[Classification and treatment of symbrachydactyly. A series of 117 cases].

In the present study, a modification has been proposed of the Blauth and Gekeler classification, aimed at a more accurate definition of appropriate surgical treatment. An analysis was made of a series of 120 cases of symbrachydactyly (117 patients); however, surgery was only performed in 86 cases (51 toe transfers in 49 patients; mean age at surgery 12 months). Type I included the separation of short and sometimes stiff fingers; type II, the 'pseudo-cleft', could be subdivided into three groups. Type IIA included those hands with more than two long and frequently hypoplastic digits, regarding which a decision had to be made between removal of rudimentary fingers or their stabilization. In type IIB, hand function was good and surgery was rarely needed. Type III (monodactylous) could also be subdivided into two categories, i.e., normal thumb in type IIIA and hypoplasia in IIIB. Finally, in type IVA, toe transfer surgery was performed on condition that wrist mobility was sufficient to compensate for the insufficient mobility of the artificial thumb on the anterior aspect of the radius. In all cases, a weak but useful pincer movement was obtained, with poor cosmetic results. In the case of toe transfers, surgery was advocated before the age of one year; and although mobility was disappointing (35 degrees active motion), good growth and excellent discrimination (5 mm on average) was observed. Symbrachydactyly is a fairly frequent congenital malformation; its diverse clinical features require a precise classification to better determine adequate treatment management.

Adolescent↗
PubMed2000

Simple closure or vagotomy and pyloroplasty for the treatment of a perforated duodenal ulcer: comparison of results.

BACKGROUND/AIMS: Treatment of the perforated duodenal ulcer continues to be a controversial subject. The purpose of our study was to compare the results of simple closure of perforated duodenal ulcer versus treatment by truncal vagotomy and pyloroplasty. METHODS: We present a prospective and randomized study of 207 patients who underwent surgical treatment due to perforated duodenal ulcer. In 117 patients the surgical treatment was simple closure and postsurgery medical treatment with proton pump inhibitors for 1 month, and in 90 patients vagotomy and pyloroplasty with no additional medical treatment. RESULTS: We applied the Visick scale in order to compare postsurgery results. The postoperative morbidity and mortality rates were the same with both techniques. Statistically, in both cases, no significant differences were found in postsurgery symptomatology. The different rates of recurrent ulcers and the reinterventions due to recurrent ulcers presented no significant statistical values. CONCLUSION: We conclude that simple closure remains the selected treatment in the majority of patients who present with a perforated duodenal ulcer. The operation is a simple and safe procedure.

Adult↗
PubMed2000

A glycoconjugate from corms of saffron plant (Crocus sativus L.) inhibits root growth and affects in vitro cell viability.

A glycoconjugate has been characterized from saffron corms (Crocus sativus L.) that inhibits the growth of roots of Nicotiana tabacum and Arabidopsis thaliana, at concentrations ranging from 1-100 micrograms m-3. Roots of seedlings grown in the presence 0.1 microgram m-3 glycoconjugate showed bulging of epidermal cells, whereas at 10 micrograms m-3, roots were completely devoid of hairs. At 100 micrograms m-3 glycoconjugate the cell walls of the root vascular tissues were thicker and, overall, the vascular tissue was enlarged. In addition, this glycan is cytotoxic to isolated tobacco cells and protoplasts, with 50% cell death induced by 0.5 and 2 micrograms m-3 glycoconjugate, respectively. Morphological and biochemical changes induced by the exposure to the glycoconjugate included cell size decrease, loss of regular cell shape, cytoplasm collapse, and release of intracellular proteins. This molecule at low concentrations (0.1 microgram m-3) mimics the effects of Yariv phenylglycosides and of mutant Arabidopsis which present defective or missing arabinogalactan-proteins (AGPs) in roots, indicating the glycoconjugate might interact with cell surface AGPs.

Arabidopsis↗
PubMed2000

[Pollicization, remains of the past or current operation].

Pollicization is a long time honored operation but more recent introduction of microsurgical techniques allowing toe to thumb transfers has changed the indications in trauma and congenital malformations. We reviewed two series of patients to assess the long-term result in both traumatized and malformed hands. Twenty-seven pollicized mutilated fingers were reviewed with a mean follow up of 9.5 years; the longest follow up published in the literature. Despite the age quite advanced of the population and multidigital amputations (more than two fingers were amputated in 16 cases), 21 patients had a good or fair result on a global score including mobility, sensibility, daily use, cortical integration, cold intolerance or pain and appearance. In congenital malformations, hypoplasia or aplasia of the thumb in presence of long fingers remains one of the best indication of pollicization. Out of 35 operated children, 27 were reviewed with a sufficient follow up (mean 6 years) to assess the result. Sensibility and growth were excellent (3 cases need some secondary shortening) mobility was close to normal in 61% of cases but the main concern was the strength which reached only 42% of the standard.

Adolescent↗
PubMed1999

Production of a cytotoxic proteoglycan using callus culture of saffron corms (Crocus sativus L.).

Saffron corms have been demonstrated to contain a proteoglycan that inhibits growth of human tumor cells. In this study, we show strong evidence indicating that callus cultures of saffron corm also synthesize such glycoconjugate. This compound is cytotoxic against human cervical epithelioid carcinoma cells (IC50 = 7 mg ml-1), and consists of approximately 90% carbohydrate and 10% protein. In order to optimize the glycoconjugate purification to complete functional and therapeutic studies, we have designed an improved method consisting of anion-exchange chromatography and reversed-phase HPLC, which can be easily scaled-up.

Antineoplastic Agents, Phytogenic↗
PubMed1999

In vitro models to study mechanisms involved in cyclosporine A-mediated glomerular contraction.

The immunosuppressive drug, cyclosporin A (CsA), which is successfully used to prevent rejection in organ transplantation, induces renal side-effects as shown by a decrease in glomerular filtration rate and ultrafiltration coefficient regulated by the tone of mesangial cells.The aim of the present study was to investigate the effect of CsA on isolated glomeruli and mesangial cells, which constitute appropriate in vitro models for renal vasoreactivity studies. The roles of different intracellular and extracellular mediators such as calcium, endothelin-1 (ET-1), prostaglandins (TXA(2 )and PGI(2)) and reactive oxygen intermediates (ROIs) were analysed. CsA caused a concentration- and time-dependent decrease in the planar cross-sectional areas of isolated glomeruli and mesangial cells as determined by image analysis. Intracytosolic free calcium concentration determined by fluorimetric analysis was significantly increased after 30 min CsA (10 microM) incubation. In the contraction experiment, the calcium antagonist verapamil inhibited the CsA response. ET-1, TXB(2) and keto-PGF(1alpha) were determined directly, however no changes were found statistically significantly different from respective controls. In contrast to these results, the ET-1 specific antibody was able to reduce CsA-mediated cell contraction. In the presence of a prostacyclin agonist iloprost, CsA-induced contraction was also modified. The role of ROIs using a 2'7'-dichlorofluorescein diacetate (DCFdAc) fluorimetric method was directly determined by observing, with 10 microM CsA, a significant production of hydrogen peroxide (H(2)O(2)), which was able alone to induce mesangial cell contraction. Coincubation with the antioxidants led to a significant inhibition of mesangial cell contraction. These results suggest that CsA caused an imbalance in the normal level of all investigated vasoconstrictive and vasodilator mediators, which shifted towards the advantage of vasoconstrictive action.

Animals↗
PubMed1999

Effects of glutamine on head and neck squamous cell carcinoma.

Glutamine supplements are being studied as protectants against the mucositis associated with radiation therapy of head and neck squamous cell carcinoma. Glutamine is an important amino acid for the maintenance of healthy gut function and nitrogen transport. It is also a preferred energy source for many types of tumors through an altered Krebs cycle. The effects of glutamine supplements on the growth of head and neck squamous cell carcinoma have not been studied. Eighteen nude mice were implanted with one established cell line, and 18 were implanted with another. The mice were paired and fed either a glutamine-rich or a glutamine-poor diet. There was not a statistically significant difference in the growth rates of the xenografts or in the weight gain of the mice between the diet groups. These findings are encouraging for the continued use of glutamine supplements in patients with head and neck squamous cell carcinoma.

Animals↗
PubMed1999

Mechanisms involved in the somatostatin-induced contraction of vascular smooth muscle cells.

In experimental models and in humans, somatostatin (SRIF) is able to contract certain vascular structures. The present experiments were designed to assess the capacity of SRIF to contract cultured rat aortic vascular smooth muscle cells (VSMC), and to analyze the possible mechanisms involved. Cells incubated with SRIF showed a significant reduction in planar cell surface area, in a time- and dose-dependent manner. This effect was partially blocked by preincubating the cells with a combination of calcium antagonists (10 microM verapamil, plus 10 microM 3,4,5-Trimethoxybenzoic acid 3-(diethylanino) octyl ester TMB)-8). SRIF was also able to stimulate myosin light-chain phosphorylation in VSMC. A small but significant increase of intracellular calcium concentration, and decreased levels of cAMP, without changes in cGMP, were detected in VSMC incubated with SRIF. A search for the known SRIF receptors present in these cells, by reverse transcription-polymerase chain reaction, only SRIF receptor-4 was found to be present. These results demonstrate the ability of SRIF to contract cultured rat VSMC. The contraction observed in these cells appears to be due to a mixed mechanism, that involves [Ca2+]i and cAMP as second messengers, and is likely mediated via SRIF receptor-4.

Animals↗
PubMed1999

Predictivity of an in vitro model for acute and chronic skin irritation (SkinEthic) applied to the testing of topical vehicles.

An in vitro human reconstructed epidermis model (SkinEthic) used for screening acute and chronic skin irritation potential was validated against in vivo data from skin tolerability studies. The irritation potential of sodium lauryl sulfate (SLS), calcipotriol and trans-retinoic acid was investigated. The in vitro epidermis-like model consists of cultures of keratinocytes from human foreskin on a polycarbonate filter. The modulation of cell viability, the release and gene expression of proinflammatory cytokines, interleukins 1alpha and 8, and morphological changes were evaluated during 3 days as endpoints representative for an inflammatory reaction. The cumulative irritation potential of the topical products was evaluated in a human clinical study by visual scoring and biophysical measurement of inflammatory skin reaction after repeated 24 h applications over 3 weeks under Finn chamber patches. All topical products that were nonirritating in the human study were noncytotoxic and did not induce cytokine expression in the in vitro acute model (day 1 exposure). All irritating controls exhibited specific cell viability and cytokine patterns, which were predictive of the in vivo human data. The ranking of mild to moderate skin irritation potential was based on the lack of cytotoxicity and the presence of cytokine patterns including gene expression specific for each irritant, using the chronic in vitro model (up to 3 days exposure). The human reconstructed epidermis model SkinEthic was shown to be a reliable preclinical tool predicting the irritation potential of topical products. Moreover, it is a useful model in a two-step tiered strategy for screening acute and chronic irritation potential for the selection of vehicles for new topical drugs.

Adult↗
PubMed1999

Cytokine profile of human bronchoalveolar macrophages and bronchial epithelial cells in response to inhalation particles of the cyclosporine derivative IMM 125.

Administration of antiasthmatic drugs in the form of inhalation particles may alter the cytokine network in the airways, independently of their pharmacological actions. Changes induced by drugs not well tolerated may potentially contribute to the immunopathology of the disease, a strongly undesirable effect. In this study, cell viability assays and characterization of the cellular profile of cytokines and chemokines were performed in order to investigate the response of human bronchoalveolar macrophages and bronchial epithelial cells in culture to inhalation particles of the cyclosporine derivative IMM 125. Interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha), and IL-8 were assayed by enzyme-linked immunosorbent assay (ELISA) in the supernatants of bronchoalveolar macrophages, and RANTES, granulocyte--macrophage colony-stimulating factor (GM-CSF), and IL-8 in those of bronchial epithelial cells. Cells were studied both under basal and stimulated conditions (lipopolysaccharide and TNFalpha were used for activating macrophages and epithelial cells, respectively). The immunosuppressant FK 506 and the glucocorticoid Budesonide served as comparison. IMM 125 did not affect cell viability (except at high concentrations and long time periods). Moreover, IMM 125 did not induce an increase in the secretion of any of the cytokines and chemokines measured with respect to nontreated cells, except for a slight increase in IL-8, an effect that was also observed for FK 506, Budesonide, and inert latex particles, and was therefore regarded as nonspecific. Furthermore, IMM 125 significantly decreased the secretion of TNFalpha, IL-1beta by macrophages, and GM-CSF by epithelial cells, suggesting an antiinflammatory potential. In conclusion, the present in vitro results point to a good tolerance of human airways to IMM 125 inhalation particles.

Administration, Inhalation↗