Search PubMed⌕ Search

Biomedical subjects

J Colin

Publications and source records attributed to J Colin.

At least 127 records · Page 7Linked to original sources
PubMed1988

[A trial use of lenses of human placental collagen in epikeratoplasty procedures].

Epikeratoplasty is a refractive surgery procedure described by Werblin and Kaufman which is simple, effective and reversible. However its development is hampered by the need of human corneas. We evaluated this procedure in rabbits and monkeys using lenticules of human collagen. The collagen is obtained from frozen human placentas, washed and subjected to pepsin digestion; it is contained in the supernatant of centrifugation and can be isolated by a physico-chemical treatment. 15 days after surgery the lenses of 14 rabbits were completely covered with a layer of epithelial cells. 6 months after surgery, the eyes of 14 monkeys were quiet and the lenses were covered with an epithelium made up of 2 to 5 layers of cells. The lens exhibited no inflammatory infiltration and there was no inflammatory reaction around the lens. These studies are still preliminary and longer term tests are necessary. These initial results are very encouraging, prompting us to develop the use of this type of material in refractive surgery.

Animals↗
PubMed1988

[Histological study of 4 lenses from epikeratoplasty. Anatomo-clinical correlation].

Four removed kerato-lens lenticles (1 for keratoconus, 1 for aphakia, and 2 for myopia) have been studied histologically. The reasons for removal of the lenticles were poor visual acuity in spite of a satisfactory anatomic result in three cases and epithelialization of the interface in one case. The epithelium presented modifications, particularly with exoserosis of basal cells and irregularities of thickness. The Bowman membrane was irregular and interrupted in some parts. The corneal stroma had few cells; the keratocytes were observed in the periphery of the lenticle and near the interface.

Adult↗
PubMed1988

[Chronic endophthalmitis caused by Propionibacterium acnes in a pseudophakic patient].

This paper reports the case of a chronic endophthalmitis with hypopion produced by propionibacterium acnes (p. a.) in a patient operated on for cataract and implanted with a posterior chamber intraocular lens. This granulomatous uveitis appeared 8 days after surgery and did not heal with a systemic corticoid-antibiotics treatment. The diagnosis was obtained by vitreous analysis. The responsibility of p. a. must be always searched in case of chronic endophthalmitis in pseudophakic patients: a specific treatment has to be used.

Aged↗
PubMed1988

[Soft intraocular silicone lenses: results after a one-year follow-up].

The main advantage of phacoemulsification is lost when the 3 mm incision has to be enlarged to at least 6 or 7 mm to permit the insertion of a PMMA lens. The major reason for the development of soft IOL is their flexibility which allows them to be folded and introduced through a small incision. We began a clinical study to determine the safety and efficacy of a new silicone lens, which is a single piece, injection molded, flexible implant. 25 patients undergoing extracapsular cataract extraction were included in this study. The silicone lens was inserted flat through the wound and the desired position was sulcus fixation. After a one year follow up period, the results were compared with those of 207 patients implanted with PMMA lenses. The visual results and the mean endothelial cell loss were similar in both groups. Iris capture was seen in 4 cases of soft lenses, probably due to the minimal haptic rigidity. Long term in vivo studies in the unique environment of the eye will be necessary to establish the biocompatibility of new soft intraocular lenses.

Aged↗
PubMed1988

[Scanning microscopy comparison of keratotomies using a diamond or steel knife].

We have compared on 4 cadaver eyes the aspect of keratotomies obtained with a diamond blade or a steel blade. We used the scanning electron microscope for the comparison. The incisions with diamond blade are much thinner than the incisions with steel blade. However the steel blade produced regular and smooth keratotomies. Whatever the blades, the microscopic appearance of the penetration was much better than the exit. The choice between cutting instruments for keratotomy depends upon these results and financial factors.

Humans↗
PubMed1987

Homology in the region containing a tRNA(Trp) gene and a (complete or partial) tRNA(Pro) gene in wheat mitochondrial and chloroplast genomes.

We have used bean mitochondrial (mt) and chloroplast (cp) tRNA(Trp) as probes to locate the corresponding genes on the mt and cp genomes of wheat and we have determined the nucleotide sequences of the wheat mt and cp tRNA(Trp) genes and of the flanking regions. Sequence comparisons show that the wheat mt and cp tRNA(Trp) genes are 97% homologous. On the wheat cp DNA, a tRNA(UGGPro) gene was found 139 bp upstream of the cp tRNA(Trp) gene. On the wheat mt DNA, a sequence of 23 nucleotides completely homologous with the 3' end of this cp tRNA(Pro) gene was found 136 bp upstream of the mt tRNA(Trp) gene, but there is only 38% homology between cp and mt wheat genomes in the intergenic regions. The overall organization of this region in the chloroplast genome (a tRNA(Trp) gene separated by about 140 bp from a tRNA(Pro) gene) is also found in the mitochondrial genome, suggesting that this mitochondrial fragment might have originated from a chloroplast DNA insertion. A comparison of the genes and of the intergenic regions located between the tRNA(Trp) gene and the tRNA(Pro) (or partial tRNA(Pro)) gene shows that there is an almost complete conservation of these sequences in the mitochondrial DNA of wheat and maize, whereas wheat mt and cp intergenic regions show more sequence divergence. Wheat mt tRNA(Trp) gene is encoded by the main mt genome (accounted for by the master chromosome) but, in the case of maize mitochondria, this gene was found to be encoded by the 2.3 kb linear plasmid, indicating that this plasmid is not dispensable in maize mitochondria.

Base Sequence↗
PubMed1987

Higher-order structure of domain III in Escherichia coli 16S ribosomal RNA, 30S subunit and 70S ribosome.

We have investigated in detail the conformation of domain III of 16S rRNA (nucleotides 913-1408), using a variety of chemical and enzymatic structure probes. The sites of reaction were identified by primer extension with reverse transcriptase using appropriate oligodeoxyribonucleotide primers. This study has been done on 16S rRNA in its naked form, in the 30S subunit and in the 70S ribosome. Data obtained with naked RNA broadly confirm the secondary structure model proposed essentially by comparative sequence analysis, and allow identification of nucleotides involved in tertiary interactions. Our results are in reasonably good agreement with structure probing experiments of Moazed et al. [1]. However, several discrepancies have been observed. Within the 30S subunit, a high number of nucleotides become unreactive whereas other nucleotides show an enhanced reactivity. This probably reflects local conformational changes. Interestingly, they are located in strategic regions of the RNA, e.g. around C1400 (involved in tRNA binding) and C1192 (involved in spectinomycin recognition). Results are also discussed together with the topographical localization of the ribosomal proteins in this area. The study on the 70S particle allows identification of regions at the interface of subunits or exposed at the surface of the ribosome.

Base Sequence↗
PubMed1987

Combination therapy for dendritic keratitis with acyclovir and vidarabine.

We treated 32 patients with dendritic keratitis with a combination of acyclovir 3% ointment and vidarabine 3% ointment or acyclovir and placebo. Patients with acyclovir alone healed in an average time of 7.7 days, while patients on the combination healed in an average of 6 days. Only one patient in the acyclovir and vidarabine group had a healing time longer than 7 days, whereas six patients in the acyclovir and placebo group had healing times longer than 7 days. By the median test, this difference in healing times was statistically significant (p = 0.035), and the combination prevented cases of prolonged ulceration.

Acyclovir↗
PubMed1986

Monoclonal antibody analysis of blood and cornea T lymphocyte subpopulations in herpes simplex keratitis.

There is now a great deal of evidence in favor of cell-mediated immunopathogenesis in herpes simplex (HS) keratitis. We used monoclonal antibodies specific for different cell subsets to analyze the blood and cornea-eluded lymphocyte subpopulations in HSV keratitis. There was a significant decrease in the proportion of cells expressing UCHT 1, OKT 4, and MID 4 antigens in the peripheral blood of patients as a whole, as opposed to sex- and age-matched controls. There was a slight decrease in OKT 4 cells in patients with herpetic keratouveitis when compared with patients with herpetic superficial keratitis, and a slight decrease in recurrent herpetic patients. Three corneal buttons showed a marked infiltration by suppressor/cytotoxic T cells, supporting the recent suggestion that lymphocytes might be cytotoxic for keratocytes.

Adult↗
PubMed1986

[Hydrophilic contact lenses and pathogenic microorganisms].

A first study was conducted on 243 hydrophilic contact lenses: 65 were macroscopically abnormal and 100 were infected with fungi. Moreover on Sabouraud's medium with chloramphenicol, 30 bacterial strains were isolated of which 25 Pseudomonas sp. (10 Ps. cepacia) and 1 Serratia liquefaciens. Then a second study was conducted on 107 among the 243 lens solutions: the 50 of the B trade mark were spoiled with 12 X 10(7) bacteria/ml and the 57 of the C trade mark with 5 X 10(7) bacteria/ml. This quantitative bacterial difference was confirmed with a qualitative one: from B trade-mark 6 Pseudomonas aeruginosa strains were isolated and from C only one. The authors emphasize the importance of Ps. aeruginosa in corneal ulcers associated with contact lenses, of lens solution composition, and of preservative usefulness.

Bacteria↗