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Biomedical subjects

K Green

Publications and source records attributed to K Green.

At least 163 records · Page 9Linked to original sources
PubMed1989

100 cases of external cephalic version, with special reference to fetomaternal transfusion.

The incidence of fetomaternal transfusion (FMT) and localization of the placenta was studied in 100 attempted external versions (ECV). In only one case could a significant FMT be detected with the Kleihauer-Betke test. No major complications occurred. Sixty per cent of the attempted versions were successful. Multiparity and either dorsal or fundal placental localization were found to be favorable factors. The determination of AFP was of no use for the detection of FMT.

Delivery, Obstetric↗
PubMed1989

Interaction between progesterone and mifepristone on intraocular pressure in rabbits.

The interaction between a topically administered progesterone, medrysone, and a steroid antagonist, mifepristone, on rabbit intraocular pressure (IOP) has been determined. Medrysone alone increased IOP significantly above parallel controls over the first three weeks; this increase was not sustained. When medrysone and mifepristone were given simultaneously the IOP increased initially, but then fell after two weeks to control levels. When mifepristone was added 14 days after medrysone, the IOP was again reduced to, or below, control levels by mifepristone. The use of mifepristone alone reduced IOP relative to controls and the further addition of medrysone at 14 days had no effect on IOP. It appears that mifepristone is an effective antagonist against progesterone effects on IOP.

Animals↗
PubMed1989

Comparative effects of pilocarpine in different vehicles on pupil diameter in albino rabbits and squirrel monkeys.

Several commercial pilocarpine preparations have been compared for their efficacy of drug delivery as evaluated by changes in pupil diameter, and return to base-line pupil size, in rabbits and squirrel monkeys. Adsorbocarpine, Isoptocarpine, Pilocar, all at 2%, and Pilopine HS gel, 4%, were used. In albino rabbits the order of efficacy, as judged by area under the curve, or maximal pupil diameter change, was Pilopine greater than Isoptocarpine = Adsorbocarpine greater than Pilocar = saline (prepared in this laboratory). In general, greater areas under the curve were associated with greater changes in pupil diameter. Pupil diameter had returned to normal by a maximum of 5 hours after drop instillation. In squirrel monkeys, the maximum pupillary change was statistically (P greater than 0.05) the same for all preparations, as was the percentage change in pupil diameter at 6 hours since pupils were still somewhat constricted at this time after drop instillation. The differences in area under the curve were minor. The greater response in primates compared to rabbits may be due to differences in pigment, intraocular kinetics and a far more active ciliary muscle in primates. Also studied were newly developed, non-surfactant containing, preservative-free polymer- and microparticle-based vehicles. Some of the vehicles, based on cyanoacrylate, modified hyaluronate, anionic copolymers, polyvinyl-pyrrolidone, cross-linked gelatin and microparticles showed greater pupillary changes and areas under the curve in rabbits compared to saline vehicle. When compared to commercial preparations in the monkey eye cyanoacrylate block copolymer and modified hyaluronate showed an increase in efficacy. Polyvinylpyrrolidone, anionic copolymer and cross-linked gelatin were equal to the commercial preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Influence of hydrogen peroxide on adenine uptake by iris, ciliary epithelium and corneal endothelium.

Hydrogen peroxide injected into the anterior chamber of adult rabbits causes a sequence of events that is not seen in young normal rabbits, yet is replicated in young rabbits receiving a catalase inhibitor. The uptake of radiolabeled adenine was measured in corneal endothelial, ciliary epithelial, and iris cells of either normal eyes, eyes injected with hydrogen peroxide or inhibitors of glutathione metabolism. Cellular adenine uptake did not exceed that of the bathing solution, except in corneal endothelia and ciliary epithelium of young animals. Under different experimental conditions intracameral hydrogen peroxide decreased adenine uptake into cells of various tissues compared the same experimental condition where only water injections was made. This occurred even with suppression of catalase activity using 3-aminotriazole. Intravitreal glutathione inhibitors had no effect on adenine uptake. The effects of intracameral hydrogen peroxide seen previously might be explained on the basis of alterations in cellular plasma membrane permeability.

Adenine↗
PubMed1989

The effects of endotoxin, glucocorticoids and prostaglandin metabolism in the rabbit iris.

Superoxide dismutase activity (SOD) was measured in the irides of control animals (n = 16) and 24 hours after the intravitreal administration of endotoxin (n = 12). Nearly a twofold increase in SOD was noted in the endotoxin-treated animals (p less than 0.001). In order to assess the induction of SOD while protecting against the inflammatory process, topical dexamethasone (dex) was administered t.i.d. for 2 days before and 1 day after endotoxin (n = 6). Dex prevented the conjunctival hyperemia, vascular injection and iritis seen with endotoxin treatment alone and blocked the induction of SOD. A similar medrysone (med) application (n = 4) failed to prevent the visible signs of ocular inflammation yet also blocked the elevation of SOD. Pretreatment with either of the cyclooxygenase inhibitors, indomethacin (n = 4) or aspirin (n = 7), failed to block the induction in SOD (p less than 0.001 and p less than 0.01, respectively). However, the induction of SOD was prevented by the phospholipase A2 inhibitor, quinacrine, and the lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA). The data indicate that a product of the lipoxygenase pathway may be mediating the induction of SOD seen with endotoxin-induced ocular inflammation.

Animals↗
PubMed1989

The effects of ascorbate, 3-aminotriazole, and 1,3-bis-(2-chloroethyl)-1-nitrosourea on hydrogen peroxide levels in the rabbit aqueous humor.

3-aminotriazole (3-AT), a catalase inhibitor, given to pigmented rabbits in 0.2% drinking solution for 43 days, produced cataractous changes and over a 50% reduction in iris and ciliary process catalase activity. Aqueous H2O2 levels were suppressed by 60% which correlated with a 77% reduction in aqueous ascorbate concentration. Intravenous 3-AT at 1.0 g/kg body weight had no effect on either aqueous ascorbate or H2O2 levels. BCNU (1,3-bis-(2-chloroethyl)-1-nitrosourea) was given intravitreally to rabbits: 3.0 mg suppressed iris glutathione reductase activity by 80%, but only increased the oxidized glutathione/total glutathione ratio to 26% from 18%. Both aqueous ascorbate and H2O2 levels were unaltered at 48 hours. Buthionine sulfoximine (BSO) was given intravitreally; at 48 hours after 4.0 mg BSO, iris-ciliary body total glutathione levels were reduced by 80%, aqueous ascorbate levels were reduced by 53%, and aqueous H2O2 levels were unaltered. A direct correlation seems to exist between aqueous humor ascorbate and H2O2 concentrations, even during suppression of tissue catalase activity. Changes in glutathione status cause peroxide levels to be greater than predicted from the aqueous ascorbate concentration.

Amitrole↗
PubMed1989

Preservative effects on the healing rate of rabbit corneal epithelium.

Benzalkonium chloride (BAK), sodium lauryl sulfate (SLS), chlorhexidine digluconate, thimerosal and polyaminopropyl biguanide were tested for their effects on the rate of corneal epithelial regrowth after mechanical lesions, and BAK and SLS after heptanol-generated lesions in rabbit corneas. Only 1.3% SLS reduced the rate of epithelial healing after three times a day drop application as determined using planar measures of epithelial regrowth. SLS, a common ingredient in soups and shampoos, should be used carefully where a lesion or wound is present in the corneal epithelium.

Animals↗
PubMed1989

Oxygen free radicals and corneal endothelium.

We have demonstrated that corneal endothelial cells are susceptible to damage from hydrogen peroxide. Hydrogen peroxide perfusion of corneal endothelium results in physiologic and anatomic disruption of corneal endothelial cells with resulting swelling of the corneal stroma. Enzymatically generated superoxide anion produced endothelial damage which could not be blocked with superoxide dismutase (which removes superoxide anion from the system), but could it be blocked with catalase which removes hydrogen peroxide from the system. This indicated that the superoxide anion was not the toxic agent, but rather hydrogen peroxide, its dismutation product. Enzymatically generated oxygen free radical in the anterior chamber of the rabbit eye resulted in an increased iris vascular permeability which persisted for up to 24 hours following anterior chamber injection of hypoxanthine and xanthine oxidase. Young animals were better able to withstand oxidative stress to the eye then were older animals. The physiologic effects of oxidative stress in young animals can be made comparable to that in the older animals by depletion of catalase with 3-aminotriazole.

Aging↗
PubMed1988

Relative frequencies of rotavirus serotypes 1, 2, 3, and 4 in Venezuelan infants with gastroenteritis.

We have used a recently developed monoclonal antibody enzyme-linked immunosorbent assay (K. Taniguchi, T. Urasawa, Y. Morita, H. B. Greenberg, and S. Urasawa, J. Infect. Dis. 155:1159-1166, 1987) for serotyping rotaviruses recovered from 134 Venezuelan infants over a period of 15 months. One hundred and nine of the specimens were typed with the following distribution: serotype 1, 48%; serotype 2, 16%; serotype 3, 22%; and serotype 4, 14%. Three specimens reacted with two different monoclonal antibodies. In addition, 6 specimens (5%) containing enough outer capsid antigen could not be typed; partial RNA sequence analysis of the glycoprotein gene from three of these six strains failed to reveal sequence differences with prototype strains that could be serotyped with the monoclonal antibodies. Variations in the recovery rates of the different serotypes were observed. Serotypes 2, 3, and 4 predominated at the beginning of the study, and serotype 1 predominated at the end of the study. Diarrheal illness appeared to be more prolonged in infants shedding rotavirus serotypes 1 and 3 than in those shedding serotypes 2 and 4.

Base Sequence↗
PubMed1988

Comparative analysis of the VP3 gene of divergent strains of the rotaviruses simian SA11 and bovine Nebraska calf diarrhea virus.

The gene encoding outer capsid protein VP3 of subpopulations of two animal rotaviruses, simian SA11 and Nebraska calf diarrhea virus (NCDV), was analyzed. Two laboratory strains of simian SA11 rotavirus (SA11-SEM and SA11-FEM) differed with respect to VP3. This dimorphism was indicated by a difference in electrophoretic mobility and a difference in reactivity with anti-VP3 monoclonal antibodies. The overall VP3 amino acid homology between the two SA11 VP3 proteins was 82.7%, whereas the VP3 protein of SA11-FEM was 98.5% homologous in amino acid sequence to NCDV VP3, suggesting that SA11-FEM VP3 was derived by gene reassortment in the laboratory during contamination with a bovine rotavirus. A comparison of the deduced amino acid sequence of the VP3 of two virulent NCDV strains and an attenuated NCDV strain (RIT 4237), revealed only five amino acid differences which were scattered throughout the protein but did not involve the trypsin cleavage sites. Of interest, the VP3 of the standard strain of NCDV which is virulent for cows differed in only one amino acid (position 23, Gln to Lys) from the VP3 of an NCDV mutant which was attenuated both for cows and for children.

Amino Acid Sequence↗