Relationships between the area under the first moment curve after single bolus injection and the integral of plasma concentrations after constant-rate intravenous infusion.
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Humans↗
Biomedical subjects
H Cheng
Publications and source records attributed to H Cheng.
A membrane blotting method for following the time course of protein radioiodination using Iodobeads.
A method for monitoring and optimizing the incorporation of radioiodide into protein is described. The use of immobilized chloramine-T (Iodobeads) combined with timed blots on nitrocellulose forms the basis of an efficient assay system. Results with Iodobeads and with the commonly utilized soluble form of chloramine-T are compared.
Absorption↗
Primary or secondary anterior chamber lens implantation after extracapsular cataract surgery and vitreous loss.
Whilst an anterior chamber lens implant (AC IOL) can be implanted during extracapsular cataract extraction with vitreous loss managed by anterior vitrectomy, lens implantation as a secondary procedure may avoid complications. We reviewed 47 consecutive cases of vitreous loss, 37 managed with primary and 10 with secondary AC IOLs. There was no significant difference in the level of final visual acuity but, as expected, it was reached earlier in the primary group (p less than 0.001). In the secondary group post-operative astigmatism was less marked (p less than 0.05) and the AC IOL haptic feet were correctly sited in the angle more frequently (p less than 0.05). Primary implant patients experienced more recurrent attacks of anterior uveitis (p less than 0.01) although the incidence of cystoid macular oedema and retinal detachment did not differ significantly. The results suggest that correct AC IOL positioning is more likely with a secondary procedure and that post-operative complications are fewer.
Cataract Extraction↗
Cortisol increases the susceptibility of rat islets to interleukin 1.
Interleukin 1 beta has been proposed to play an essential role in the pathogenesis of IDDM by direct interaction with the pancreatic beta-cell. Glucocorticoids are widely used as immunosuppressive agents and have been suggested to interfere both with the production and action of interleukin 1. The aim of the present study was to evaluate the interaction between cortisol and interleukin-1 on the pancreatic beta-cell function in vitro. Newborn rat islets were precultured for seven days before they were exposed to interleukin 1 with or without addition of cortisol. The release of insulin to the culture medium was followed and the insulin content and biosynthesis were measured after one week in culture. Cortisol, 10(-6) mol/l, resulted in a 50% lower rate of release during the culture period and a similar reduction in storage and biosynthesis of insulin in the islets at the end of the culture period. In the control islets interleukin 1, 0.5 microgram/l, resulted in an early increase in insulin release followed by a marked reduction. In the cortisol-treated islets interleukin 1 increased the release up to 72 h followed by a moderate decrease. In the control islets, interleukin 1 reduced the insulin content to about 50%, whereas in the cortisol-treated islets interleukin 1 resulted in an even greater reduction, to about 30%. This additional effect of cortisol seems not to be due to an augmented cytotoxic effect of interleukin 1 as indicated by the DNA content of the islets and the viability of the cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Esophageal diverticulum associated with carcinoma of the esophagus--a report of four cases.
During a 25-year period, four patients with esophageal diverticulum associated with carcinoma of the esophagus underwent surgery. The results were satisfactory. The clinical features included a long history of diverticulum and the presence of a carcinoma of the esophagus in close proximity to the former. Inflammation within the diverticulum and in the mucosa around the diverticulum was noted. The closer the diverticulum to the carcinoma, the more severe the inflammation. Therefore, diverticulitis and esophagitis may be important factors leading to the development of carcinoma of the esophagus, and patients with esophageal diverticulum should be followed up regularly and the diverticulum resected as early as possible if inflammation within the diverticulum or peri-diverticular esophagitis is found.
Diverticulum, Esophageal↗
[Fluorescent determination of magnolol by surfaceactive emulsifier].
Fluorescent determination of magnolol has been effected employing the sensitivity- and stability-enhancing action of the non-ionic surfaceactive emulsifier OP. As a result the accuracy of determination is raised by 2 orders of magnitude as compared to that of ultraviolet spectrophotometry.
Biphenyl Compounds↗
[Correlation between retinal nerve fiber layer defect, neuroretinal rim area and visual impairment in primary open angle glaucoma].
120 eyes of normal subjects, 150 eyes of ocular hypertension, and 132 eyes of primary open angle glaucoma (POAG) were examined the retinal nerve fiber layer (RNFL), neuroretinal rim area (NRA), visual field, dark adaptation and pattern reversal visual evoked potential (PVEP), revealing that RNFL defect and NRA correlated with visual field defect, threshold of dark adaptation and latency of PVEP. RNFL examination using red free photographic technique yielded 96% sensitivity in glaucoma detection and 95% specificity in identifying normal eyes. Modified semiquantitative criterion for assessing RNFL defect had a good reproducibility. The mean NRA in normal eyes was 2.22 +/- 0.35 mm2. Therefore, 95% of the normal subjects had rim areas greater than 1.64 mm2; 82% of patients with POAG had NRA less than 1.64 mm2. 20.1% of the eyes of ocular hypertension had RNFL defect and 37.6% had NRA below the 95% lower point, suggesting that some patients with increased intraocular pressure could have structural abnormalities. The authors proposed that ocular hypertension without visual field defect but with significant RNFL defect and/or NRA decrease should be regarded as in a preliminary stage of POAG.
Dark Adaptation↗
[Survey on knowledge and attitudes on AIDS among administrative and medical staff and policemen].
This survey was conducted among administrative, medical staff and policemen at county level in Yunnan province of PR. China concerning knowledge and attitude on HIV/AIDS. The main statistics of this survey were about the characteristics of the three groups, the degree of being interested in knowledge on HIV/AIDS and the sources of the knowledge and their attitude.
Acquired Immunodeficiency Syndrome↗
[Investigations on the resources of Chinese gallnuts in Shanyang County, Shaanxi, Province].
This paper deals with the resources of Chinese gallnuts in Shanyang County, Shaanxi Province, Sumac trees and winter host bryophyte were investigated. Use suggest that a base for production of Chinese gallnuts be set up.
China↗
The downfield resonances in the 1H NMR spectra of Azotobacter vinelandii and Pseudomonas putida seven-iron ferredoxins.
Pseudomonas putida and Azotobacter vinelandii ferredoxins each contain one [4Fe-4S] cluster and one [3Fe-4S] cluster. Their polypeptide chains are nearly identical, differing by only 15 residues out of a total of 106. T1 measurements and temperature dependence studies of the 1H NMR spectrum of each ferredoxin demonstrate that all six resolved downfield resonances are near an iron-sulfur center. The five most downfield resonances are shown to arise from protons on cysteinyl beta-carbons by incorporation of cysteine deuterated at the beta-carbon into cell protein. The sixth peak (10.5 ppm) is shown to be a non-cysteinyl proton. This peak resolves into two resonances of approximately equal intensity at temperatures below 15 degrees or above 25 degrees C. A nuclear Overhauser effect observed between the two downfield-most resonances of A. vinelandii ferredoxin indicates that they originate from a geminal pair of beta-cysteinyl protons. An Overhauser effect observed between the resonances at 22.3 and 15.7 ppm, in conjunction with other results, implies that the resonance at 22.3 ppm arises from a beta-proton on the 3Fe-center-bound Cys16, while the resonance at 15.7 ppm arises from Cys45 beta-proton, which is bound to the 4Fe center. The five most downfield resonances are pH-dependent. The sixth peak (10.5 ppm in P. putida ferredoxin) is pH-independent. Possible origins for the observed pH dependencies are discussed.
Azotobacter↗
Comparison of mesenteric with antimesenteric crypt and villus populations in the mouse jejunal epithelium.
Variation in the size and composition of crypts and villi along the length of the intestinal tract is well known. Here we investigate possible variation around the circumference of the intestine. This is a concern because most studies have ignored potential circumferential variation and its implications for experimental design in cell kinetic studies. We compared the crypt and villus populations of the mesenteric half with those of the antimesenteric half of proximal mouse jejunum. The branching crypt index and crypt and villus dimensions were measured. We found no evidence of differences in the branching crypt index, in the mean crypt and villus size, nor in the distribution of crypt and villus sizes between these two populations.
Animals↗
Whole population cell kinetics of jejunal and colonic epithelium in lactating dams.
Previous studies make it likely that the response of the intestinal epithelium as a whole to lactation is different from that observed in the crypt population alone. We confirm this difference by whole population cell kinetics measurements of jejunal and colonic epithelium in mice that have been suckling pups for various lengths of time. We found that the fraction of cells in S phase in jejunal epithelium was significantly increased after only 1 week of lactation, maintained this elevated level after 2 weeks of lactation, but returned to normal during the third week of lactation. The cell number density in jejunum was also significantly higher after 2 and 3 weeks of lactation before returning to normal by 4 weeks. In the colonic epithelium no changes were found in the distribution of cells in G1, S, and G2 + M phases. However, a significant increase in cell number density was observed after 2 weeks of lactation, followed by a sharp decrease to a level significantly below that of normal mice after 3 and 4 weeks of lactation. We conclude that the observed significant increase in the fraction of S phase in jejunal epithelium of lactating mice is probably due to a smaller relative expansion of the villus population when compared with the expansion of the crypt population. Our data also indicate that a number of cell kinetic parameters in the intestinal epithelium of lactating mice are changing throughout the period of lactation. Thus the intestinal epithelium is probably not in a steady state during lactation.
Animals↗
Theoretical analysis of the flow of cells over villi of the small intestine.
The flow of epithelial cells over villi of mouse small intestine is calculated from equations of cell number balance and irrotational flow. The influence of both villus geometry and crypt distribution about the villus base are studied. Specific, experimentally verifiable predictions are made.
Animals↗
Constant-rate intravenous infusion methods for estimating steady-state volumes of distribution and mean residence times in the body for drugs undergoing reversible metabolism.
Equations for the steady-state volumes of distribution (Vss) and the mean residence times in the body (MRT) are derived for a drug and its metabolite subject to reversible metabolism and separately infused intravenously at a constant rate to steady state of both compounds. The Vss and MRT parameters are functions of the integrals of plasma concentrations, plasma concentrations at steady state, and times to reach steady state of both drug and metabolite. In addition, the MRT values are functions of the infusion rates. These equations were validated by computer simulations and comparison with IV bolus dose parameters. These relationships extend the ability to assess the pharmacokinetics of linear reversible metabolic systems.
Infusions, Intravenous↗
Dysmenorrhea, menorrhagia, premenstrual syndrome, and immunologic screening in habitual abortion.
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Abortion, Habitual↗
The P2 phage old gene: sequence, transcription and translational control.
The old (overcoming lysogenization defect) gene product of bacteriophage P2 kills Escherichia coli recB and recC mutants and interferes with phage lambda growth [Sironi et al., Virology 46 (1971) 387-396; Lindahl et al., Proc. Natl. Acad. Sci. USA 66 (1970) 587-594]. Specialized transducing lambda phages, which lack the recombination region, can be selected by plating lambda stocks on E. coli that carry the old gene on a prophage or plasmid [Finkel et al., Gene 46 (1986) 65-69]. Deletion and sequence analyses indicate that the old-encoded protein has an Mr of 65,373 and that its transcription is leftward. Primer extension analyses locate the transcription start point near the right end of the virion DNA. A bacterial mutant, named pin3 and able to suppress the effects of the old gene, has been isolated [Ghisotti et al., J. Virol. 48 (1983) 616-626]. In a pin3 mutant strain, carrying the old gene on a prophage or plasmid, the amount of old transcript is greatly reduced. The effect of the pin3 mutation is abolished by the wild-type allele of argU, an arginine tRNA that reads the rare Arg codons AGA and AGG, which are used for eight of the 14 Arg codons in the old gene. Thus the pin3 allele probably stalls translation of the old mRNA, causing this mRNA to be degraded. Isoelectric focusing and electrophoretic analysis identify the old gene product as a basic protein of approx. 65 kDa.
Amino Acid Sequence↗
Asymmetric distribution of actin mRNA and cytoskeletal pattern generation in polarized epithelial cells.
We analysed the distribution of actin mRNA in intestinal epithelial cells using in situ hybridization of 35S-labelled cytoplasmic beta-actin RNA. We found that the distribution of actin mRNA generally parallels that of polymerized actin, i.e. there is an accumulation of actin mRNA in the apical end of villous epithelial cells. Furthermore, the development of this asymmetric localization of actin mRNA appears to parallel the elaboration of the cytoskeleton during cellular differentiation. We discuss the possibility that the interaction between actin and its mRNA may be important for the establishment and maintenance of cytoskeletal pattern in polarized epithelial cells.
Actins↗