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Biomedical subjects

E Kay

Publications and source records attributed to E Kay.

At least 73 records · Page 4Linked to original sources
PubMed1989

Presentation and antimicrobial treatment of acute orofacial infections in general dental practice.

Information on the presentation of orofacial infections and the use of antimicrobial agents in general dental practice in the United Kingdom was obtained using a postal questionnaire. Six hundred dentists were randomly selected and a total of 340 replies were received, giving a response rate of 57%. The dental practitioners estimated that acute infection was present in only a minority (approximately 5%) of patients. A total of seven different antibiotics were prescribed, in a variety of regimens, for the treatment of bacterial infection. However, the majority of dentists (46-62%) preferred a 5-day course of penicillin (250 mg, qid) for bacterial conditions other than acute ulcerative gingivitis, for which most practitioners (89%) prescribed 3 days of metronidazole (200 mg, tid). Nystatin was the most frequently selected anticandidal agent and topical acyclovir the most popular therapy for Herpes simplex infection.

Anti-Bacterial Agents↗
PubMed1989

Acute gastric stress ulceration: prophylaxis with allopurinol.

Acute gastric stress ulceration was induced in rats by cold restraint and was not associated with alteration of gastric pH or serum gastrin level. Cimetidine and oral and intravenous allopurinol were prophylactic but allopurinol was more effective in reducing the depth of the lesion and acted without alteration in gastric pH. The efficacy of allopurinol in preventing stress ulceration offers further indirect evidence of the role of ischaemia and oxygen free radical generation in the aetiology of stress ulceration.

Allopurinol↗
PubMed1988

Design for today.

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Dental Offices↗
PubMed1988

A sense of style.

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Dental Offices↗
PubMed1982

Assembly of the fertilization membrane of the sea urchin: isolation of a divalent cation-dependent intermediate and its crosslinking in vitro.

To analyze the mechanism of assembly of the fertilization membrane of the sea urchin Strongylocentrotus purpuratus, we inhibited the ovoperoxidase that catalyzes dityrosine formation to isolate an uncrosslinked, soft fertilization membrane (SFM). The SFM intermediates were stabilized by divalent cation-dependent interactions: in the absence of divalent cations, the SFM became amorphous and less refractile and released proteins into the surrounding medium. We term the remaining structures "wraiths." The rate of this disaggregation was increased in solutions of low ionic strength, but 5-10 mM divalent cations (Ca2+, Mg2+, Mn2+ or Ba2+) prevented disaggregation. Wraiths could be reassembled into structures that resembled SFM by readdition of divalent cations. The SFM contained active ovoperoxidase and could be hardened in vitro by washing away the ovoperoxidase inhibitor and adding H2O2. After hardening, certain proteins of over 100 kd were excluded from SDS-polyacrylamide gels, suggesting that these proteins contain the substrates for crosslinking. We propose that the SFM is a divalent cation-dependent intermediate on the pathway of fertilization membrane assembly containing tyrosyl residues that are appropriately juxtaposed for crosslinking.

Calcium↗
PubMed1979

Lima bean proteinase inhibitor. Origins of circular dichroism bands and modification by Br2- and (CNS)2-.

Origins of CD bands in lima bean proteinase inhibitor were deduced from an acetylation-deacetylation study of the sole tyrosyl residue in the protein (Tyr 69), and by analogy with Bowman-Birk soybean proteinase inhibitor, a homologous protein with similar spectral properties. Tyr 69 is relatively inaccessible to N-acetylimidazole; 100-fold molar excess of the reagent in the presence of 6 M guanidine hydrochloride elicited about 70 to 80% O-acetylation. A broad negative CD band centered around 280 nm arises mainly from the longest wavelength transition of cystinyl side chains (epsilon L--epsilon R approximately equal to -0.8 M-1 cm-1 per disulfide). The second cystinyl transition gives rise to a positive CD band of a comparable intensity at 247 nm. The Lb vibronic transition of Tyr 69 has negative CD around 280 nm, contributing approximately 10% of the total CD intensity at 278 nm (epsilon L--epsilon R approximately equal to -0.5 M-1 cm-1). The 232 nm positive shoulder is from the La vibronic transition of Tyr 69. Radical anions, Br2- and (CNS)2-, generated by the irradiation of N2O-saturated inhibitor solutions containing KBr or KCNS, reduced tyrosyl CD without affecting disulfide CD bands, indicating that the radical anions damaged Tyr 69 without altering protein conformation. The inhibitor modified at Tyr 69 by Br2- and (CNS)2- retained full activity toward trypsin and chymotrypsin. The irradiation of the inhibitor in the air-saturated solution led to loss in tyrosyl as well as cystinyl CD bands and decline in both antiproteinase activities.

Bromides↗
PubMed1979

Differences in the circular dichroism spectra of of eu- and heterochromatin fractions from rat liver.

Significant differences are observed between the CD spectra of eu- and heterochromatin prepared by fractionating mechanically sheared rat liver chromatin on linear sucrose density gradients. Heterochromatin has a broad positive CD at 270--280 nm, a cross-over point at 256 nmn, and a negative shoulder at 248 nm. Euchromatin displays a shift in the positive peak to 267 nm and the cross-over point to 254 nm, as well as an intensification of the 267 nm peak. The negative shoulder at 248 nm is absent in euchromatin. These spectral differences between eu- and heterochromatin are present in both low and high ionic strength media. Mechanical shearing does not induce CD alteration and anomalous light scattering is absent in our system. The greater RNA content of euchromatin compared to heterochromatin cannot account for the spectral differences. These results suggest that the DNA conformation of euchromatin is distinct from that of heterochromatin and they may provide clues to the reasons for the greater transcription of euchromatin.

Animals↗