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Biomedical subjects

C Villa

Publications and source records attributed to C Villa.

14 recordsLinked to original sources
PubMed2002

Microwave-assisted preparation of cyclic ketals from a cineole ketone as potential cosmetic ingredients: solvent-free synthesis, odour evaluation, in vitro cytotoxicity and antimicrobial assays.

Some cyclic ketals derived from (+)1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-6-one were obtained in excellent yields by microwave activation under solvent-free conditions, as a 'green chemistry' procedure. The results obtained using acidic alumina containing 7% p-toluenesulfonic acid, as mineral support, are reported and compared with those obtained by classical methods. The new compounds were tested for their olfactive character and for a potential cosmetic use. In vitro skin cytotoxicity tests were carried out on the most promising compounds, by using NCTC 2544 human keratinocytes as target cells. They all displayed slight cytotoxic effects which were one order of magnitude lower than those found with sodium dodecylsulphate positive control. Two compounds that resulted interesting as toothpaste aromas, were submitted to antimicrobial assays and showed their activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus hominis, Propionibacterium acnes and Candida albicans.

Anti-Infective Agents↗
PubMed2001

Practical experience with a high Dk lotrafilcon A fluorosilicone hydrogel extended wear contact lens in Spain.

PURPOSE: Several research studies on high Dk soft contact lens materials have been published, but little has been reported from practical clinical experience with these new materials. This study reports in-practice clinical experience with the lotrafilcon A fluorosilicone hydrogel material from a 6-month study in Spain. METHODS: Eighty-five patients were dispensed lotrafilcon A lenses (Focuse NIGHT & DAY [CIBA Vision Corporation]) for monthly replacement by 13 investigators from eight practices. The recommended wear schedule was daily wear for the first week and then up to 6-night extended wear through the first month and up to 30-night extended wear through 6 months. Follow-up visits were at 1 week, 1 month, 3 months, and 6 months. Clinical and patient subjective data were collected at each visit. RESULTS: Among patients who continued in the study at each visit, Snellen visual acuity (VA) of 20/25 or better was achieved by at least 96% of all eyes at all visits; lens surfaces assessments for front surface deposits, front surface wetting, and back surface debris averaged less than grade 1 (0-4 scale) for all lenses at all visits; biomicroscopy grades averaged well below grade 1 (0-4 scale) for all eyes at all visits; acceptable or optimal fit was assessed for 97% or more of all lenses at all visits. These patients rated the average overall comfort, vision, and handling above 9 (0-10 scale) at 6 months and 98% reported satisfaction with the lenses at 6 months. Eighty-two percent of patients dispensed completed the study. Seven patients were discontinued because of fit, and seven were discontinued because of positive biomicroscopy signs. CONCLUSIONS: The lotrafilcon A lens performed well clinically and it was accepted well by patients, with most practitioners recommending and most patients wearing it for up to 30 nights extended wear. Practitioners should be attentive to fit and discomfort complaints at dispensing and follow-up and may want to recommend lubricating or rewetting drops for those patients with dryness symptoms.

Adolescent↗
PubMed2000

Shorter survival of SDF1-3'A/3'A homozygotes linked to CD4+ T cell decrease in advanced human immunodeficiency virus type 1 infection.

The SDF-1 3'A allelic polymorphism has been reported to influence either positively or negatively the progression of human immunodeficiency virus type 1 (HIV-1) disease. Therefore, the SDF-1 genotype of 729 HIV-1-infected individuals pooled from 3 distinct cohorts was determined. A statistically nonsignificant association between the SDF1-3'A/3'A genotype and accelerated disease progression was evident among seroconverters (n=319), but a striking correlation of decreased survival after either diagnosis of AIDS according to the 1993 definition or loss of CD4(+) T cell counts <200 was observed. The relative hazards for SDF1-3'A/3'A homozygotes, compared with heterozygotes and wild-type homozygotes were 2.16 (P=.0047), for time from diagnosis according to the 1993 Centers for Disease Control and Prevention AIDS case definition (AIDS-'93) to death, and 3.43 (P=.0001), for time from CD4(+) T cells <200 to death. Because no difference in survival was observed after diagnosis according to AIDS-'87, the association of the SDF1-3'A/3'A genotype with the accelerated progression of late-stage HIV-1 disease appears to be explained for the most part by the loss of CD4(+) T lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1999

[Loco-regional block in ophthalmic surgery: single drug or drug combination with hyaluronidase? Randomized prospective study].

UNLABELLED: The aim of this study is the comparison between the use of bupivacaine alone and a mixture of bupivacaine, mepivacaine and hyaluronidase in both retrobulbar and peribulbar blockades for eye surgery. Three hundred ninety-nine consecutive adult patients scheduled for cataract surgery with regional anaesthesia were included in this prospective, randomized and partially blind study. Peribulbar blockade was performed on 199 patients (group P). Ninety-nine of them received a mixture of local anaesthetics and hyaluronidase (sub-group M), while 100 received bupivacaine alone (sub-group B). Retrobulbar blockade was performed on 200 patients (group R): 100 of them received the mixture with hyaluronidase (sub-group M), while 100 received bupivacaine (sub-group B). The interval between anaesthesia and motor blockade (onset time), the presence of residual ocular movements, the need of further anaesthesia, the quality of anaesthesia, the ocular tone, the length of anaesthesia and possible complications were registered. RESULTS: Retrobulbar blockade has the only advantage of a shorter onset time, while peribulbar blockade shows a longer anaesthetic effect. Mixture with hyaluronidase (the sub-group M) has a shorter onset time, a lesser need of further anaesthesia, fewer residual ocular movements and a better quality of anaesthesia. CONCLUSIONS: Local anaesthetics mixture with hyaluronidase associated with peribulbar blockade presents the advantages of rapidity, duration and better quality without the risks of retrobulbar blockade side effects.

Adult↗
PubMed1998

Characterisation of an improved two-dimensional p22121 crystal from bovine rhodopsin.

Dialysis of rhodopsin isolated from bovine rod outer segments resulted in the formation of a new two-dimensional crystal form suitable for electron crystallography. The crystals obtained were tubular or single layers and showed p22121 symmetry (a=60.6(+/-0.8) A, b=86.3(+/-1.6) A). For the first time the size and order of the crystals allowed us to take electron diffraction patterns showing spots to a resolution of about 3.5 A. Images were recorded at liquid nitrogen temperature using a high voltage field emission electron microscope. Out of a large number of images 20 crystalline areas were selected and processed with the MRC image processing software. A projection structure of bovine rhodopsin to 5 A resolution was calculated using amplitudes and phases extracted from these images. The achieved resolution exceeds the resolution of all previously obtained structures of frog, bovine and squid rhodopsin crystals. In this map small differences are observed compared to the previous maps. Helix 5 seems to be even more highly tilted and between the arc-shaped feature and helix 5 a peak is present suggesting that helix 3 is prolonging this feature towards helix 5. These observations are in agreement with the latest model for the three-dimensional arrangement of rhodopsin. The resolution achieved as well as the availability of electron diffraction data suggest that there is a good possibility to collect data from tilted crystals and calculate an improved three-dimensional structure of rhodopsin.

Animals↗
PubMed1997

[A large symptomatic gastric leiomyoma. A case report and considerations of the treatment possibilities].

The authors describe the case of a female patient affected with large symptomatic gastric leiomyoma, six centimeters in diameter, who presented to clinical observation referring gastric pain and melena. The first gastroscopy showed massive bleeding from a submucosal gastric lesion. The lesion was not endoscopically resectable and the injective endoscopic treatment of bleeding failed. The patient was surgically treated with laparotomic excision of the leiomyoma. She was back home in ten days. The authors describe this case to discuss the possibility to resect large gastric leiomyomas using endoscopic resection indeed surgical approach. They also enhance the validity of surgical treatment for its safety and radical approach to large lesions.

Emergencies↗
PubMed1993

Projection structure of rhodopsin.

Light absorption by the visual pigment rhodopsin triggers, through G-protein coupling, a cascade of events in the outer segment of the rod cell of the vertebrate retina that results in membrane hyperpolarization and nerve excitation. Rhodopsin, which contains 348 amino acids, has seven helices that cross the disk membrane and its amino terminus is extracellular. A wealth of biochemical data is available for rhodopsin: 11-cis retinal is bound to lysine 296 in helix VII; glutamic acid 113 on helix III is the counterion to the protonated Schiff's base; a disulphide bridge, cystine 110-187, connects helix III to the second extracellular loop e2 (refs 13, 14); the carboxy terminus has two palmitoylated cysteines forming a cytoplasmic loop i4 (ref. 15); three intracellular loops i2, i3 and i4 mediate activation of the heterotrimeric G protein transducin; glutamic acid 135 and arginine 136 at the cytoplasmic end of helix III affect binding of transducin. But to provide a framework to interpret these data, not only for rhodopsin but for other G-protein-coupled receptors, requires the structure to be determined. Here we present a projection map of rhodopsin showing the configuration of the helices.

Animals↗