Biomedical subjects
Publications and source records attributed to M E Rogers.
Nineteen pigs in a 500 sow herd died from anthrax over a period of 95 days. This paper describes some of the problems encountered and how they were dealt with, including the risks to public health, the disposal of slurry and the cleansing and disinfection of the premises after the herd was slaughtered.
1. Sialic acid moieties of erythrocyte membrane glycoproteins are the principal determinants of the negative charge on the cell surface. The resultant electrostatic repulsion between the cells reduces erythrocyte aggregation and hence the low shear rate viscosity and yield stress of blood. 2. Using g.c.-m.s., a decrease in sialic acid content has been observed in the major erythrocyte membrane glycoprotein, glycophorin A, obtained from nine diabetic patients compared with that from seven normal control subjects [median (range): 3.30 (0.01-11.90) versus 18.60 (3.20-32.60) micrograms/100 micrograms of protein, P less than 0.02]. 3. Erythrocyte aggregation, measured by viscometry as the ratio of suspension viscosity to supernatant viscosity (LS/S) in fibrinogen solution, was increased in ten diabetic patients compared with ten normal control subjects (mean +/- SEM, 37.6 +/- 1.3 versus 33.8 +/- 0.6, P less than 0.02). 4. In the patients in whom both viscometry and carbohydrate analysis were performed, the decrease in erythrocyte glycophorin sialylation and the increase in erythrocyte aggregation in fibrinogen solution were related statistically (LS/S correlated negatively with glycophorin sialic acid content, r = 0.73, P less than 0.05). 5. Decreased glycophorin sialylation provides an explanation at the molecular level for increased erythrocyte aggregation and it may be important in the pathogenesis of vascular disease in diabetes.
This article presents the basic elements of Rogers' science of unitary human beings. It defines science, explicates nursing as a science and an art, addresses the meaning of the principles of hemodynamics, and discusses the building blocks of these principles. Several theories arising from the science of unitary human beings are elaborated, and noninvasive therapeutic modalities are discussed as part of nursing practice.
Head-related transfer functions for differently centered narrow noise bands were obtained on 6 subjects. Derived from these measurements were covert peak areas (CPAs), defined as the spatial constellation of loudspeakers that generates maximal sound pressure at the entrance of the ear canal for specific bands of frequency. On the basis of previous data, we proposed that different frequency bands served as important spectral cues for monaural localization of sounds from different loci and that location judgments were directed toward the CPAs associated with the different bands. In the first study, the stimuli were bandpass filtered so that they contained only those frequencies whose associated CPAs occupied either the monaural listener's "upper" or "lower" spatial regions. Loudspeakers, separated by 15 degrees, were stationed in the left hemifield, ranging from 0 degree to 180 degrees azimuth and -45 degrees to 60 degrees elevation. Subjects reported the loudspeaker from which the sound appeared to originate. Judgments of the sound's elevation were in general accord with the CPAs associated with the different frequency segments. In the second study, monaural localization tests were administered in which different 2.0-kHz-wide frequency bands linked with specific CPAs were notch filtered from a 3.5-kHz highpass noise band. For the control condition, the highpass noise was unfiltered. The data demonstrated that filtering a frequency segment linked with specific CPAs resulted in significantly fewer location responses directed toward that particular spatial region. These results demonstrate in greater detail the relation between the directional filtering properties of the pinna and monaural localization of sound.
The glycosylation of the light chain (GPIIbL) of glycoprotein IIb, one of the glycoproteins constituting the receptor for fibrinogen, fibronectin, and the von Willebrand factor on platelet cell surfaces, was investigated using fast-atom-bombardment mass spectrometry (f.a.b.-m.s.). Complex-type N-glycans were observed, attached to Asn-60. The most abundant oligosaccharide is a disialylated biantennary structure substituted with fucose on the chitobiose core. Mono-sialylated biantennary, and di- and tri-sialylated triantennary structures were found as minor constituents of the N-glycan population. The amino acid sequence of GPIIbL was fully mapped by f.a.b.-m.s., thereby providing the first direct evidence for the absence of O-glycosylation.
Comparison of the diets of sympatric gorillas and chimpanzees allows an analysis of niche separation between these two closely related species. Qualitatively, their diets are similar, being dominated by an equally diverse array of fruit species complemented with vegetative plant parts, seeds and insects. Gorillas eat more vegetative plant parts than do chimpanzees, but niche separation is most obvious in periods of fruit scarcity when the two species show different strategies that reduce competition for food. Their abilities to overcome mechanical and physical plant defences appear to differ, as gorillas are able to subsist entirely on abundant vegetative foods. Chimpanzees show social adjustment, foraging alone or in small groups, to reduce intra-specific competition for scarce fruit resources. Thus it seems that subtle physiological differences have far-reaching repercussions, defining potential evolutionary pathways for social organization and allowing sufficient niche separation between species.
The positive- and negative-ion f.a.b.-mass spectra and the fragmentation of sulphated oligosaccharides derived from ovine lutropin are described. Negative-ion f.a.b.-m.s. of methylated derivatives offers a sensitive and rapid method for screening glycans for sulphation, for defining the location of sulphated residues, and for sequencing sulphated branches. Positive-ion f.a.b.-m.s. gives complementary data on non-sulphated branches in both complex and hybrid-type sulphated structures.
We have employed fast atom bombardment mass spectrometry (FAB-MS) to screen the N-linked oligosaccharides of Bowes melanoma tissue plasminogen activator (mt-PA), and recombinant t-PAs produced by Chinese hamster ovary cells (rt-PA) and by a gene-enriched melanoma cell line (rmt-PA). These studies have confirmed the published structures for rt-PA, but are not in agreement with some of the structures reported for mt-PA. In the latter glycoprotein we have identified a novel structure as the major oligosaccharide attached to Asn-184 and Asn-448. This is a biantennary oligosaccharide consisting of a fucosylated trimannosyl core to which are attached two GalNAc(1----4)GlcNAc antennae, one of which carries a sialic acid linked at the 6-position of the GalNAc. Minor constituents are sialylated on both or neither antennae. The sialylated GalNAc moiety is unique in N-linked glycoproteins. The majority of complex structures in rmt-PA contain N-acetyllactosamine moieties at both the Asn-184 and Asn-448 sites with the novel oligosaccharide occurring as a minor component at the Asn-184 site. This study demonstrates the power of mass spectrometric strategies based on high-field two-sector FAB-MS for structure elucidations of natural and recombinant glycoproteins.
We compared the safety and efficacy of a single 400-mg dose of ofloxacin, ofloxacin (200 mg) once daily for 3 days, and trimethoprim-sulfamethoxazole (160:800 mg) twice daily for 7 days for the treatment of acute uncomplicated cystitis (urinary tract infection [UTI]) in women. At 5 weeks posttreatment, 35 (81%) of 43 patients treated with single-dose ofloxacin, 40 (89%) of 45 treated with 3 days of ofloxacin, and 41 (98%) of 42 treated with trimethoprim-sulfamethoxazole were cured (P = 0.03, single-dose ofloxacin group versus trimethoprim-sulfamethoxazole group). Retreatment for symptomatic recurrent UTI was given to 7 (16%) of 43 patients initially treated with single-dose ofloxacin, 3 (7%) of 45 patients treated with 3 days of ofloxacin, and 0 of 42 patients treated with trimethoprim-sulfamethoxazole (P = 0.01, single-dose ofloxacin group versus trimethoprim-sulfamethoxazole group). There was a trend in each of the three treatment groups toward an association between persistent or recurrent episodes of significant bacteriuria and a history of UTI in the past year and with diaphragm use. Ofloxacin was more effective than trimethoprim-sulfamethoxazole in eradicating Escherichia coli from rectal cultures during or soon after therapy, but there were no differences at later follow-up visits. Adverse effects were equally common among the three treatment groups. We conclude that single-dose ofloxacin was less effective than 7 days of trimethoprim-sulfamethoxazole for treatment of uncomplicated cystitis in women, while the 3-day ofloxacin regimen and the trimethoprim-sulfamethoxazole regimen were not significantly different in efficacy.
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We compared 7-day regimens of ciprofloxacin in dosages of 750 and 1000 mg twice daily with doxycycline 100 mg twice daily for the treatment of nongonococcal urethritis in 178 men enrolled in a prospective, randomized, double-blind trial. The overall clinical response was comparable in the three treatment groups at both 2 and 4 weeks after therapy. However, among patients who initially had cultures positive for chlamydia, Chlamydia trachomatis was reisolated within 4 weeks after treatment in none of 10 doxycycline-treated patients, in 11 (52%) of 21 patients treated with 750 mg of ciprofloxacin twice daily, and in six (38%) of 16 patients treated with 1000 mg of ciprofloxacin twice daily. Each of the recurrent strains was identical in serotype to the original infecting strain. We conclude that ciprofloxacin in dosages as high as 2 g daily is inadequate for treatment of chlamydial urethritis in men, often resulting in relapsing infections.
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We describe procedures, based upon fast atom bombardment mass spectrometry, for characterising the carbohydrate chains in glycoproteins and for determining sites of glycosylation. Strategies for rapidly screening glycoproteins to ascertain the types of sugar chains present and the degree of heterogeneity are presented. Protocols are given for sequencing O- and N-linked glycans. These strategies exploit simple purification steps and afford data at high sensitivity.
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