Biomedical subjects
Publications and source records attributed to K Gilbert.
Short-term circulatory effects with the maximum recommended dose of inhaled albuterol (Proventil) were studied on 12 asthmatic patients between 33 and 39 weeks' gestation. The mean maternal blood pressures and heart rates, systolic/diastolic ratios of the uterine arcuate and umbilical arteries, and fetal heart rates and aortic velocities were unaffected during the first 2 hours after dosing.
Community-acquired pneumonia is a common medical illness, with clinical outcomes ranging from mild illness with rapid and complete recovery to a fulminant clinical course with morbid complications followed by death. A systematic review of the literature on pneumonia prognosis has identified a variety of demographic factors, symptoms and physical examination findings, comorbid illnesses, laboratory abnormalities, and etiologic agents that are independently associated with short-term mortality in patients with this illness. By combining these prognostic factors, investigators have developed a variety of indices to predict short-term mortality. Although these predictive instruments vary with respect to the patient populations studied, number of predictor variables included, statistical methods used, and overall clinical performance, these models can assist physicians in assessing patient prognosis and in making important management decisions such as the initial site of care (ie, home v hospital). Assessment of patient prognosis has also been used by clinicians and health services researchers who use the hospital severity of illness-adjusted mortality rate as a measure of the quality of medical care provided. Because the majority of patients with this illness survive, future assessments or predictions of prognosis in patients with community-acquired pneumonia should also evaluate a spectrum of other important health outcome measures including the occurrence of morbid complications, symptom resolution, quality of life, return to work and usual activities, and patient satisfaction with care.
The present studies were designed to examine the influence of dietary selenite supplementation on the initiation phase of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis and to correlate selenite-induced changes in the binding of DMBA metabolites to rat mammary cell DNA with the ultimate tumor incidence. Diets formulated to contain selenium, as sodium selenite at 0.1, 0.5, 1, 2, or 4 micrograms/g were fed for 2 weeks prior to and 2 weeks following treatment with DMBA (5 mg/kg body weight). Food intake and weight gain did not differ among treatments. Tumor incidence correlated inversely to the quantity of selenium consumed (r = -0.99). Final tumor incidences were 52, 32, 24, 14, and 10% for rats fed 0.1, 0.5, 1, and 4 micrograms selenium/g, respectively. In a separate group of rats fed a diet containing 4 micrograms selenium/g during both the initiation and promotion stages the final tumor incidence was 4.8%. Selenite supplementation for 2 weeks markedly depressed the occurrence of individual and total DMBA-DNA adducts. The final mammary tumor incidence correlated positively with total DMBA-DNA adducts (r = 0.99). These studies clearly demonstrate that selenite can inhibit the initiation stage of mammary carcinogenesis. This reduction in tumor incidence is likely due to a reduction in carcinogen metabolism and ultimately adduct formation.
A total of 945 non-related individuals from four isolated population groups from the Northern Aegean Sea (Greece)--Alonissos, Oxilithos, Skopelos, and Glossa, has been typed for 16 polymorphic systems of the blood, namely A1A2B0, MNS., Rhesus (C, c, Cw, D, E, e), Kell, Duffy (a,b), Kidd (a); Hp, Tf subtypes, Gc, Gm (1, 2, 3, 5, 13), Km (1); aP, AK, PGM1, EsD, and 6-PGD. The distribution of phenotype and gene/haplotype frequencies shows a considerable interpopulational variability, which is discussed considering the history of these populations as well as the impact of locally acting microevolutionary factors such as drift and founder effects. The average coefficient of gene diversity GST comes to 0.0147, whereas Wahlund's variance is on average 0.0154, and Wright's Fst = 0.0147. Genetic distance analysis reveals a pattern of similarities, which is in conformity with the history of the populations under study.
The protonmotive cytochrome b protein of the mitochondrial bc1 respiratory chain complex contains two reactions centers, designated Qo and Qi, which can be distinguished by the effects of different inhibitors. The nucleotide sequences have been determined of the mitochondrial cytochrome b genes from a series of mouse cell mutants selected for increased inhibitor resistance. Each mutant contains a single nucleotide change which results in an amino acid substitution. When the proximity of the altered amino acid residues to the histidines involved in heme ligation is considered, the results support a model for cytochrome b folding in which there are eight transmembrane domains rather than the nine of the Widger-Saraste model. Replacement of the Gly38 residue by valine results in resistance to the Qi inhibitors antimycin A and funiculosin but not 2-n-heptyl-hydroxyquinoline-N-oxide. Based upon sequence comparisons of mitochondrial and bacterial cytochrome b and chloroplast b6 proteins, the region of the molecule involved in antimycin binding is as highly conserved as those domains involved in heme ligation. It is suggested that the antimycin binding domain of cytochrome b is involved in forming the Qi reaction center. Alterations of the Gly142 and Thr147 residues result in resistance to myxothiazol and stimatellin, respectively. While both inhibitors block the Qo reaction center, the two mutations do not confer cross-resistance to each other. This region of cytochrome b is the most highly conserved during evolution and these inhibitor binding sites probably occur within the protein domain constituting the Qo reaction center. In addition, there is a less conserved region of the protein, defined by the Leu294 residue, which may function in binding the hydrophobic portions of Qo inhibitors.
Serum samples from ten endogamous populations of Assam, India-Brahmins, Kalitas, Kaibartas, Muslims, Ahoms, Karbis, Kacharis, Sonowals, Chutiyas, and Rajbanshis-were typed for G1m (1, 2, 3, 17), G3m (5, 10, 11, 13, 14, 15, 16, 21, 26), and Km (1). Among Brahmins, Kalitas, Kaibartas, Muslims, Ahoms, Sonowals, Chutiyas, and Rajbanshis, five different Gm haplotypes were found: Gm1,17;21,26; Gm1,17;10,11,13,15,16; Gm1,2,17;21,26; Gm1,3;5,10,11,13,14,26; and Gm3;5,10,11,13,14,26. Kacharis and Karbis show only four of these haplotypes: Gm3;5,10,11,13,14,26 is absent among them. The intergroup variability in the distribution of these haplotypes is considerable, which can be explained by the ethnohistory of these populations. Genetic distance analysis, in which five Chinese population samples were included, revealed the existence of three main clusters: 1) North and Central Chinese; 2) Kalitas, Kaibartas, Chutiyas, Rajbanshis, Muslims, and Brahmins; and 3) Ahoms, Sonowals, Kacharis, South Chinese, and Karbis. The clusters suggest some genetic relation between these four Assamese populations and South Chinese, which is again understandable considering the ethnohistory of the populations of Northeast India. In the Km system, too, a remarkable variability is seen in distribution of phenotype and allele frequency.
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Escherichia coli characteristically lyses upon treatment with most beta-lactam antimicrobial agents. In contrast, an investigational aminothiazole cephem, CGP 31523A, produced a new combination of antibacterial effects: it was highly bactericidal without causing cell wall degradation or lysis. Killing was associated with the formation of vacuolated filaments. Because the compound bound to penicillin-binding proteins (PBPs) 1a and 3, we investigated the role of PBP 3 in modulation of lysis caused by inhibition of PBP 1a. A temperature-sensitive mutant with a nonfunctional PBP 3 lysed when treated with CGP 31523A. The combination of a PBP 1 inhibitor (cefsulodin) and a PBP 3 inhibitor (aztreonam) also caused filamentation and death without lysis of wild-type cells over a narrow concentration range. We conclude that cooperative effects between PBPs in E. coli can lead to a dissociation of bacterial killing and lysis.
Genetic polymorphism of 16 red-cell antigens, enzymes, serum proteins and Hb variants was investigated in 214 male and female individuals belonging to the Meiteis and a Brahmin caste group living in Imphal (Manipur, Northeast India). Ethnohistorical records suggest that the Meiteis are of Mongoloid origin, while the original Brahmin settlers represent the easternmost part of the so-called Caucasoids. The markers studied are: A1A2BO, MNSs, Rh-system, Duffy, Diego; Gm, Km, Gc, Hp, Tf, Cp; Hb; aP, AK, EsD and LDH. The comparison between the two groups on the basis of the markers studied showed that the Meiteis and Brahmins are very close to each other with respect to most of the loci except Gm, EsD and Hb, where significant statistical differences were found.
Ten different population groups of Assam - Brahmins, Kalitas, Kaibartas, Rajbanshis, Muslims, Ahoms, Chutias, Kacharis, Karbis and Sandwals - have been typed for haptoglobin and for transferrin (Tf) and Gc subtype polymorphisms. Tf and Gc allele subtype frequencies show a considerable inter-population heterogeneity. From genetic distance analysis it appears that the populations under study form some distinct clusters, which can be explained by the historical and ethnic affiliations of these populations. Especially the distribution of Gc subtype alleles reveals some Mongoloid admixture among Assamese populations, which is reflected by the presence of Gc1A8 alleles in them.
Lens fiber proteins with apparent molecular weights 57,000, 70,000, 82,000, and 100,000 were components in urea insoluble, membrane-rich fractions. Monoclonal antibodies against these proteins labeled membranes by immunofluorescence microscopy of sheep lens cryosections and are thus referred to as membrane proteins MP57, MP70, MP82, and MP100. MP70 has previously been localized in fiber junctional membranes (Kistler et al 1985, J Cell Biol 101:28-35). Using radioimmunoassays, the authors found a different membrane protein composition for the cortical and nuclear sheep lens regions. In addition, the membrane protein composition altered with the overall lens age. All the above membrane antigens were eventually cleaved by proteolysis in older fibers, and their degradation patterns could be grouped into distinct classes. The results are of basic importance for cataract research.
"Ball and socket"-like membrane processes interlock fiber cells in the sheep lens cortex, but appear reduced deeper in the lens. Wheat germ agglutinin (WGA) binds preferentially to these ball and socket structures, and more weakly to other membrane regions. On protein blots, 125I WGA binds to glycoproteins with 140,000 and 32,000 apparent molecular weight, the smaller protein also binding 125I fibronectin. In two animal cataract models, the intense WGA labeling of globular bodies replaces the spotty WGA staining pattern associated with the ball and sockets in the normal lens.
A method of performing chemical-shift imaging is described that avoids some of the disadvantages inherent in the techniques which use spin echos and phase encoding. A series of FIDs are recorded during the application of a series of static gradients and the spectral image is reconstructed using a conventional filtered back-projection algorithm.
Mixed cell cultures of syngeneic lymph node (LN), spleen, or thymus and gamma-irradiated, syngeneic lymphoma cells of transplantable reticulum cell sarcomas (gamma-RCS) produced within 24 hours high titers of interleukin 2 (IL-2) and immune interferon in their supernatant (SN). These lymphokine titers were much higher than those seen after stimulation with allogeneic cells. SN also had marked enhancing activity for antibody production by anti-T-cell serum plus complement-treated spleen cells to trinitrophenylated polyacrylamide in vitro. This activity could be removed by absorption with cells of an IL-2-dependent cytotoxic cell line. Mixtures of gamma-RCS and LN cells from SJL/J F1 hybrid mice produced these lymphokines only when the non-SJL parent contributed H-2s or H-2b, but not H-2k or H-2d, in the I-region. These I-region restrictions were similar to those observed previously with respect to the ability of T-cells from SJL F1 hybrids to give proliferative responses to gamma-RCS in vitro and of these mice to support tumor growth in vivo. gamma-RCS also induced rapid interferon production in vivo, but serum titers 24 hours after injection consisted primarily of interferon resistant to pH 2 and neutralized by antibody to virally induced interferon (IFN-alpha/beta), and the production of IFN-alpha/beta was not subject to the same genetic restrictions. Although reticulum cell sarcoma cell extracts had no detectable effect in vitro, they were capable of inducing transient IFN production in vivo.
The question, whether the seasonal variation of the birth frequencies are changing with the increase of birthcontrol practice in the population is subject of the present study. The changes of the relevant demographic parameters in this context are discussed first. The study is based on the official monthly records of live- and stillbirths from 1826 to 1979 in Land Bremen (an urban district of northern Germany). For analysis, the material is standardized to equal month length. Trend effects were eliminated using the mean curve. To eliminate stochastic effects, the material is summarized using intervals formed analog to the changes in the birth rate. The means of these intervals illustrate two typical figures; the first is characteristic for the period prior to 1905, the second is characteristic for the years following (excluding the periods from 1915 to 1922 and from 1973 to 1978). The transition of these figures occurred at the change of the century. It is regarded in context with the beginning reduction of birth rate at this time. Whereas for the 19th Century, the seasonal changes, particularly from winter to spring, are regarded as a main cause of physiologic adaptation followed by stimulation of the gonadal gland, "sociologic factors" are taken into account for the seasonality of the birth rates in the 20th Century.
The changes of the secondary sex ratio in Bremen (North Germany) from 1826 up to 1978 are compared with those of Germany in the period from 1872 to 1978. To some extent there are marked differences. The oscillation of the secondary sex ratio in Bremen is more extended in Germany. On the average in Bremen the values are lower in the 19th century than in the 20th. For Germany higher values are observed in the years between 1915 and 1959. The changes of reproductive performance, indicated by birth rate. Supposing that the primary sex ratio is dependent on the time of insemination within the intermenstruum, the same figures of monthly distribution of secondary sex ratio and birth frequency can be expected. In fact, the seasonal variations proved to be not significant and do not show the expected parallel figures.
With respect to difficult research conditions the problems of taking biologically relevant somatometric measurements for the determination of habitus variants are discussed. Under consideration of these difficulties several somatometric characters are selected by comparing the correlations based on the data of two series measured by the authors and three series taken from literature. However, attention is drawn to the fact that no complete characterization of habitus variants will result by means of these few measurements but yet some important relevant criteria.
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