Corticosteroid suppression of trauma-induced hyaluronan in rabbit cornea and aqueous.

BACKGROUND: Corneal and aqueous hyaluronan have recently been shown to react in response to several different types of trauma, including cataract surgery. In order to find ways to influence the reaction, we have evaluated the effect of topical dexamethasone (Isopto-Maxidex, Alcon Universal Ltd, Fort Worth, Tex) or indomethacin (Confortid, Dumex Ltd, Copenhagen, Denmark) on the postoperative hyaluronan concentration in rabbit cornea and aqueous after extracapsular lens extraction. METHODS: The drugs were administered as topical eye drops three times daily. The hyaluronan concentration in rabbit cornea and aqueous after extracapsular lens extraction was measured with a radioligand assay. RESULTS: Dexamethasone treatment (1 mg/mL) significantly suppressed the increase in corneal hyaluronan seen after extracapsular lens extraction, 2 (p < or = 0.0022) and 3 weeks (p < or = 0.0002) after surgery, while indomethacin did not induce any significant difference at 2 weeks. When the dexamethasone concentration was lowered to 0.1 and 0.2 mg/mL, there was still a significant decrease (p < or = 0.009) in hyaluronan concentration, but at lower concentrations of dexamethasone (0.01 and 0.02 mg/mL), no significant decrease was seen. The increase in aqueous hyaluronan concentration seen 2 days after surgery in untreated eyes was significantly lowered by both dexamethasone (p < or = 0.0076) and indomethacin (p < 0.036). CONCLUSIONS: Dexamethasone lowers reactive corneal and aqueous hyaluronan concentration in vivo after extracapsular lens extraction.

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 5.

The structure of the capsular polysaccharide (S5) elaborated by Streptococcus pneumoniae type 5 has been investigated by using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure: (Formula: see text) In this structure, L-PneNAc stands for 2-acetamido-2,6-dideoxy-L-talose (pneumosamine) and D-Sug for 2-acetamido-2,6-dideoxy-D-xylo-hexos-4-ulose. The latter sugar accounts for the lability of S5 towards alkali. N.m.r. spectra indicate heterogeneity in S5, most probably associated with the hexosyl-4-ulose residue.

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 2, a reinvestigation.

The structure of the capsular polysaccharide from Streptococcus pneumoniae type 2 has been reinvestigated, specific degradations and n.m.r. spectroscopy being the main methods used. It is concluded that the polysaccharide is composed of hexasaccharide repeating-units having the following structure, which differs from that previously proposed. formula; see text)

Structural studies of the O-antigenic polysaccharide of Escherichia coli O86, which possesses blood-group B activity.

The O-specific side-chains of the lipopolysaccharide from Escherichia coli O86:K2:H2 have been investigated using n.m.r. spectroscopy, methylation analysis, and specific degradations, and shown to be composed of the pentasaccharide repeating-unit (formula; see text) which represents the biological repeating-unit. The blood-group B activity was confirmed by an enzyme-linked immunosorbent assay.

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae types 15B and 15C.

The structures of the capsular polysaccharides (S-15B and S-15C) from Streptococcus pneumoniae types 15B and 15C have been investigated by using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the polysaccharides are composed of pentasaccharide repeating-units having the following structure: (Formula: see text). In this structure, R is H (80%) or CH2CH2N+Me3 (20%). S-15B further contains O-acetyl groups, approximately 0.7 per repeating unit, which have not been located. The capsular polysaccharides S-15F and S-15A, which have been studied previously, are also composed of pentasaccharide repeating-units, containing the same sequence of sugars, but in a linear arrangement.

Structural studies of an extracellular polysaccharide (K21b) elaborated by Klebsiella type 21b.

The capsular polysaccharide from a new capsular serotype of Klebsiella, K21b, has been investigated, using n.m.r. spectroscopy, methylation analysis, and specific degradations as the main methods. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula; see text)

Structural studies of the O-antigen polysaccharide of Salmonella thompson, serogroup C1 (6,7).

The structure of the O-antigen polysaccharide of Salmonella thompson, serogroup C1 (6,7) has been investigated mainly by methylation analysis, n.m.r. spectroscopy, specific degradations by a phage-associated enzyme, N-deacetylation-deamination, and f.a.b.-m.s. It is concluded that the structure involves the following repeating unit. (formula; see text) There are two populations of chains, with and without alpha-D-glucopyranosyl groups, 3-linked to an alpha-D-Manp residue, and only the latter type is hydrolysed by the phage enzyme. The alpha linkage of the third Manp residue is cleaved by the O14 phage enzyme. The structure, with or without the alpha-D-glucopyranosyl group, represents the biological repeating-unit.

Structural studies of the O-specific side-chains of the Escherichia coli O2 lipopolysaccharide.

The structure of the O-specific side-chains of the Escherichia coli O2 lipopolysaccharide has been investigated, different 1H- and 13C-n.m.r. techniques being the main methods used. It is concluded that they are composed of pentasaccharide repeating-units having the following structure, in which D-Fuc3NAc is 3-acetamido-3,6-dideoxy-D-galactose. ----4)-beta-D-GlcpNAc-(1----3)-alpha-L-Rhap-(1----2)-alpha-L-Rh ap-(1----3)-beta-L-Rhap-(1----2 increases 1 alpha-D-Fucp3NAc.

Change in student attitudes to medical school after the introduction of problem-based learning in spite of low ratings.

Students' attitudes to, and opinions of, their studies at medical school were investigated with the help of a questionnaire. They were asked to what extent the medical school encouraged independent, critical thinking, problem-solving skills, decision-making, studying outside the textbook and other behaviours and skills that teachers in higher education usually put forward as important. It was found that students generally had a low opinion of the extent to which their education encouraged such virtues, mean figures ranging between 3.5 and 4.6 on a 10-grade scale. The students felt that their studies to a large extent encouraged focus on details and preparation for examinations. The questionnaire was given to the students after 2 1/2 years of traditional preclinical studies and at the end of the first clinical year. There were significant but numerically small differences for some of the items at the end of the year. However, when problem-based learning (PBL) was introduced during the first clinical year, there was a substantial change: there were now significant and numerically larger differences for seven of the nine items, even though the students were asked to give their opinion of the whole of their time at medical school on both occasions, not only of the last year. There were no other changes in the curriculum or the teaching methods other than the introduction of PBL. The change in attitudes did not depend on the student's appreciation of PBL; students' opinion of PBL was low, indicating that most of them disliked it.

Production and characterization of monoclonal antibodies directed against Bordetella pertussis lipopolysaccharide.

Hybrid cell lines producing monoclonal antibodies against Bordetella pertussis lipopolysaccharide (LPS) were established. The specificity of the antibodies was ascertained by enzyme-linked immunosorbent assay (ELISA) and ELISA-inhibition experiments with LPS and delipidated polysaccharide fragments (PS-1 and PS-2) prepared from B. pertussis LPS. Monoclonal antibody 9-1-H5 reacted with B. pertussis LPS only, whereas monoclonal antibodies 6-4-H6 and 9-2-A8 reacted with PS-1 and PS-2 as well as B. pertussis LPS. The antibodies did not react with LPS prepared from B. parapertussis and B. bronchiseptica in an LPS-specific ELISA. A monoclonal antibody-based sandwich ELISA was developed for detection of B. pertussis LPS. This assay had a detection limit of B. pertussis LPS in concentrations ranging from 0.16 to 0.32 microgram/ml. The assay was also shown to be specific for the detection of whole B. pertussis bacteria. No cross-reactions were observed with strains of Branhamella catarrhalis, Neisseria meningitidis, Streptococcus miteor, Haemophilus influenzae, or Legionella pneumophila. The monoclonal antibodies might be useful for the detection of soluble antigens and whole bacteria in clinical samples and for studies of the immunochemical structure of B. pertussis LPS.

The sensitivity of hyaluronan analysis of pleural fluid from patients with malignant mesothelioma and a comparison of different methods.

BACKGROUND: Hyaluronan may be used as a marker for malignant mesothelioma, thus indicating its mesodermal origin. METHODS: The sensitivity as a diagnostic test of three different methods for hyaluronan analyses of pleural fluid was examined in patients with biopsy-verified malignant pleural mesothelioma. RESULTS: A quantitative high-performance liquid-chromatography (HPLC) method was performed on fluids from 43 patients. Using a cutoff level of 100 mg/l, higher levels were noted in 30 (70%) patients, with a median value of 220 mg/l (mean, 560 mg/l; range, 20-6600 mg/l). An identical median value (220 mg/l) was obtained with a radioassay method when simultaneously performed on paired samples from 21 patients (correlation coefficient, 0.91). A qualitative precipitation test using 0.5% cetylpyridinium chloride combined with a quantitative viscosimetric method was significantly less sensitive (P < 0.01). CONCLUSION: Hyaluronan analyses is beneficial in distinguishing malignant mesothelioma if methods such as the evaluated HPLC or radioassay with a sensitivity of 70% toward mesothelioma are used and other known causes of elevated content are considered.

Influence of radial keratotomy on endogenous hyaluronan in cornea and aqueous humour.

BACKGROUND: Hyaluronan is known to appear in corneal wound tissue and is probably involved in the healing process. We measured the changes of endogenous hyaluronan in rabbit cornea and aqueous after radial keratotomy. METHODS: Corneal and aqueous hyaluronan concentrations were measured at different time intervals after radial keratotomies. Hyaluronan was extracted from corneal tissue with two methods employing either pronase or NaCl and measured with a radioimmunoassay. Histochemical staining for hyaluronan was done on the operated eyes. RESULTS: Changes in corneal hyaluronan showed a similar time course with either extraction method. Maximal concentration was reached after 7 to 14 days with a return to normal values in 60 days. Aqueous hyaluronan and proteins were not significantly altered after surgery. Histochemical staining of the corneas demonstrated hyaluronan around the incisions along their entire extent. Blood vessels were absent in the wounds. An increase in elongated fibroblast-like cells was seen in the wound area. CONCLUSIONS: Both quantitatively and histochemically, there is a pronounced increase of corneal hyaluronan in avascular, radial keratomy wounds in the rabbit. The findings suggest a role of hyaluronan in corneal wound healing.