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PubMed1995

Ultrasound and dual X-ray absorptiometry measurement of the calcaneus: influence of region of interest location.

Ultrasound measurements of the calcaneus are related to incidence of osteoporotic fracture. Such measurements are generally made at fixed coordinates relative to a footplate. This study compares measurements at an anatomically located region of interest (ROIanat) and at fixed coordinates (ROIfixed), with bone mineral density measurements, in 84 postmenopausal women. Bone mineral density (BMD) was assessed using dual energy X-ray absorptiometry at both ROIs as well as at lumbar spine and femoral neck. Broadband ultrasound attenuation and velocity of sound were measured using a CUBA system at ROIanat and ROIfixed. Additionally, broadband ultrasound attenuation at ROIfixed was measured using a Walker Sonix instrument. Mean bone mineral density, broadband ultrasound attenuation and velocity of sound did not differ significantly between ROIfixed and ROIanat, although broadband ultrasound attenuation by Walker Sonix (81.4 +/- 14.6 dBMHz-1) was significantly (P < 0.001) greater than that by CUBA (63.7 +/- 14.2 dBMHz-1). The relationship between broadband ultrasound attenuation and BMD differed significantly between the 2 ROIs and the correlation of this relationship was significantly greater at ROIfixed than at ROIanat(r = 0.74 versus 0.46, P < 0.01). The differing relationship may reflect structural variation at different regions. ROI selection may thus be a possible confounding factor in ultrasound measurement.

Absorptiometry, Photon↗
PubMed1991

Occluding junctions in the epithelia of the gut-associated lymphoid tissue (GALT) of the rabbit ileum and caecum.

The zonulae occludentes of the dome epithelia and adjacent non-dome epithelia in four locations of the gut-associated lymphoid tissue (GALT) in the rabbit ileum and caecum (Peyer's patches, sacculus rotundus, caecal lymphoid patches, appendix) were studied in freeze-fracture replicas. In all locations the zonulae occludentes of the dome epithelium are composed of more junctional strands than in the corresponding non-dome epithelium. In the dome epithelia of Peyer's and caecal lymphoid patches the zonulae occludentes show considerable structural variation; the number of superimposed strands is approximately 10 (range 5-18). In the dome epithelia of sacculus rotundus and appendix, in addition to zonulae occludentes, extended networks of junctional strands (fasciae occludentes) are present particularly between M-cells and enterocytes. The zonulae occludentes consist of approximately 8 to 9 (range 5-15) superimposed strands; the fasciae occludentes extend up to a depth of 20 microns on the lateral membranes. The presence of the fasciae occludentes correlates with the appearance of regularly shaped clusters of lymphocytes, which are most developed in the dome epithelia of sacculus rotundus and appendix. These results suggest (1) that in contrast to the dome epithelia of Peyer's and caecal lymphoid patches those of sacculus rotundus and appendix are compartmentalized, and (2) that the mobility of lymphocytes and diffusion of antigens in the dome epithelia of sacculus rotundus and appendix is restricted.

Animals↗
PubMed1987

Mutations affecting translation of the bacteriophage T4 rIIB gene cloned in Escherichia coli.

Mutant ribosome binding sites of the bacteriophage T4 rIIB gene, resident on an 873 bp DNA fragment, were cloned into a plasmid vector as in-frame fusions to a reporter gene, beta-galactosidase. The collection of mutations included changes in the region 5' to the Shine/Dalgarno sequence, a mutation of the Shine/Dalgarno sequence, the alternate initiation codons GUG, AUA and ACG, and mutants in which several closely spaced initiation codons compete with each other on the same mRNA. The results show that the secondary structure variations we have installed 5' to the Shine/Dalgarno sequence have little effect on translation. GUG is essentially as good an initiator of translation as AUG when they are assayed on separate messages, but is outcompeted at least 50-fold in the sequence AUGUG. AUA and ACG are poor start codons, and are temperature sensitive. The initiation codon pair AUGAUA, in which the AUG is only two nucleotides from the Shine/Dalgarno sequence, displays a novel cold-sensitive phenotype.

Base Sequence↗
PubMed1982

Interactions between MHC-encoded products and cloned T-cells. I. Fine specificity of induction of proliferation and lysis.

To study the interactions between T cells and class I MHC products, we developed in vitro a T-cell line reactive to H-2Kb stimulating cells and derived T-cell clones from it. Although the T-cell line could proliferate in the absence of exogeneous T-cell growth factors when stimulated with H-2Kb spleen cells, each of the derived T-cell clones required both H-2Kb stimulating cells and an external source of T-cell growth factor for its propagation. Each of the T-cell clones was also cytolytic for H-2Kb target cells. Such T-cell clones allowed the comparison of the antigenic requirements for proliferation and cytolysis. By using H-2Kb mutant mice, we found that while the original anti-H-2Kb T-cell line reacted with each of the six mutants tested, the individual T-cell clones could be distinguished in terms of their reactivity pattern. Similar fine specificity patterns were found when H-2Kb mutant cells were used as stimulating or target cells for any given T-cell clone. Each of the three monoclonal H-2Kb-specific antibodies reacting with different epitopes of the H-2Kb molecule totally inhibited H-2Kb-induced proliferation and lysis by the T-cell clones. Further blocking studies involved use of Fab antibody fragments and definition of their reactivity on cells from the H-2Kb mutants. We concluded that: (1) blocking with a monoclonal antibody does not prove identity of alloantigens recognized by the T-cells and the antibody; (2) a monoclonal antibody could either block or not block H-2Kb-CTL interactions depending on structural variations of the H-2Kb molecule not affecting the CTL-H-2Kb functional interaction; (3) blocking one type of H-2Kb-T-cell interaction (induction of proliferation) always affects the other type (cytolysis).

Animals↗
PubMed1994

Preclinical toxicology and tissue platinum distribution of novel oral antitumour platinum complexes: ammine/amine platinum(IV) dicarboxylates.

The preclinical toxicology and tissue platinum distribution of a series of six orally given antitumour platinum complexes [ammine/amine platinum(IV) dicarboxylates] with structural variations of their alicyclic amine (c-C5, c-C6 or c-C7), axial dicarboxylate (CH3, C3H7 or NHC2H5) or leaving substituents (Cl2 or OCOOCO) was studied in the mouse. Platinum tissue levels measured at 48 h after a single oral dose at 0.5 of the MTD were highest in the liver (6.0-19 micrograms/g) and second highest in the kidney (2.8-12 micrograms/g), and these levels were up to 5 times higher than those reported with equi-toxic doses of i.v. cisplatin and i.v. carboplatin. Platinum levels in the lung, heart, spleen, skin, skeletal muscle and brain were all < or = 3.1 micrograms/g at this dose level. Liver platinum levels measured at 2 h, 2 days, 6 days and 10 days after a single oral dose at the MTD ranged widely (from 15 to 109 micrograms platinum/g), were related to the number of carbon atoms in the axial dicarboxylate and alicyclic amine groups (r = 0.9389) and showed a diversity of time-course profiles. Elevations of plasma ALT activity were recorded with single oral doses of JM225 and JM256 at the MTD. Accumulation of platinum in the liver with repeated oral dosing weekly for 4 consecutive weeks at 0.5 of the MTD occurred with JM269 (3.3-fold increase, P < 0.05) and JM225 (2.4-fold increase, P < 0.05), and elevated plasma ALT activity (44 +/- 33 IU/l) was recorded with repeated oral doses of JM269. JM216 was selected from this series of analogues for further study on the basis of the elevated plasma ALT activity (JM225, JM256 and JM269), liver platinum accumulation (JM269 and JM225), poor activity against human ovarian carcinoma xenografts (JM291) or severe emetogenesis (JM221) of other examples. Following a single oral dose of JM216 at the MTD, transient reductions in the WBC (nadir, 1.6 x 10(9)/l, 2 days, 74% reduction), platelet count (nadir, 613 x 10(9)/l, 10 days, 33% reduction) and bone marrow cellularity (nadir, 0.5 x 10(7) nucleated cells/femur, 4 days, 75% reduction) were found, and these had recovered by 21 days after treatment. Jejunal mucosal disaccharidase activity following single MTDs indicated that small-intestinal mucosal damage was less severe for oral JM216 (nadir maltase activity, 68% +/- 16% of control, NS) than for i.v. cisplatin (nadir maltase activity).(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1986

Phosphofructokinase activity in fibroblasts from patients with Alzheimer's disease and age- and sex-matched controls.

The activity of the enzyme phosphofructokinase (PFK) was comparable in cultured skin fibroblasts from eight patients with Alzheimer's disease and eight age- and sex-matched controls. Mean activities were similar in the two groups whether measured under nonallosteric conditions at pH 8.0 or under allosteric conditions at pH 7.0, in the presence of 0.1 or 1 mM ATP. Activities of PFK in Alzheimer's disease and control cells also showed a similar temperature dependence and similar isozyme patterns on column chromatography. These results argue against the existence of significant structural variations of PFK in Alzheimer's disease.

Adenosine Triphosphate↗
PubMed1990

Carnivora: the primary structure of hemoglobin from adult coati (Nasua nasua rufa, Procyonidae).

The complete primary structure of the hemoglobin from the adult coati (Nasua nasua rufa) is presented. The erythrocytes contain one hemoglobin component and two globin chains. The isolation of globin chains was achieved by reversed-phase HPLC on a column of Nucleosil-C4. The primary structures of globin chains and tryptic peptides was determined in liquid- and gas-phase sequenators. The sequence of the alpha and beta-chains of coati compared with those of other Carnivora species. Results are discussed with respect to structural variations and the phylogenetic relationship.

Amino Acid Sequence↗
PubMed1996

Human adenosine A2a receptor (A2aAR) gene: systematic mutation screening in patients with schizophrenia.

Several lines of evidence suggest an involvement of adenosine A2a receptor (A2aAR) mediated adenosinergic neuromodulation in the etiopathogenesis of schizophrenia. We therefore performed a systematic mutation scan of the complete coding region of the human A2aAR gene in a sample of 42 schizophrenic patients. We detected one rare naturally occurring receptor variant (Gly-340-Ser) and two silent mutations (405C/T and 1083C/T). To our knowledge the Gly-340-Ser substitution is the first naturally occurring molecular variant of the A2aAR identified. Determining the frequency of the three variants in 42 unrelated healthy controls, we observed a significant trend towards an overrepresentation of the 1083T variant in patients when compared to controls (p = 0.041). This trend was followed up in a large independent replication sample. However, we were not able to confirm the original trend in the second sample (p = 0.367). The Ser-340 variant was found in a single schizophrenic individual. Investigation of the patient's family revealed independent segregation between the Ser-340 variant and psychiatric illness. Our data suggest that genetically determined structural variation of the A2aAR does not play a major role in the development of schizophrenia.

Alleles↗
PubMed1991

Intraepidemic variants of influenza virus H3 hemagglutinin differing in the number of carbohydrate side chains.

During the epidemic outbreak in the region of Greifswald in the winter 1974/75, we found influenza virus variants which showed differences in the electrophoretic mobility of HA. Among the 25 isolates 13 were of slower and 12 of higher mobility. HA1 of 6 isolates was studied by determining the number of the carbohydrate side chains and by direct sequencing of vRNA. Evidence is presented that variants showing a slower electrophoretic mobility of HA1 had consistently acquired a seventh carbohydrate side chain at Asn 126 in epitope A. All the isolates differed from the reference strain A/Port Chalmers/1/73 by the loss of the oligosaccharide at Asn 81. The field strain A/Dresden/3/71 possessed only 5 oligosaccharides in HA1. These results suggest that changes in glycosylation are an important mechanism in the structural variation underlying antigenic drift of HA.

Antigenic Variation↗
PubMed1994

Sister chromatid differentiation in 5-bromo-2'-deoxyuridine-substituted chromosomes: a study with DNA-specific ligands and monoclonal antibody to histone H2B.

Human and Chinese hamster chromosomes were obtained from cells grown in the presence of 5-bromodeoxyuridine (BrdU) for (a) one replicative round, (b) two replicative rounds, (c) one replicative round followed by another round in thymidine and (d) the last period of synthetic phase. Untreated chromosomes and chromosomes treated with UV radiation after previous staining with 33258 Hoechst as photosensitizer were studied in order to investigate the mechanism(s) responsible for BrdU-induced sister chromatid differentiation (SCD). Metaphases were prepared by (1) standard methanol-acetic acid fixative for subsequent investigation with Giemsa or DNA-specific dyes such as ethidium bromide, acridine orange and monoclonal antibodies to double- or single-stranded DNA; (2) the procedure for observation under phase-contrast or electron microscopy; and (3) the cytospin method for subsequent immunoreaction with a monoclonal antibody to histone H2B. Our data exclude the possibility that the presence/absence of BrdU in the template strand might affect chromatin organization and thus resistance, while confirming that UV-induced DNA alteration is not sufficient, by itself, to explain SCD mechanism(s). That molecules other than DNA play a role in explaining SCD production is indicated by the fact that BrdU incorporation induces alterations in DNA-histone H2B interactions which, in turn, seem to produce structural variations in chromatin, possibly at the level of condensation, as monitored by phase-contrast and electron microscopy.

Animals↗
PubMed1989

Differences in chromosome A arrangement between Drosophila madeirensis and Drosophila subobscura.

The proximal half of the A (= X) chromosome of D. madeirensis has a gene arrangement very similar to the A1 or A6 inversions found in D. subobscura. Polytene chromosome analysis of hybrids between D. madeirensis and strains of D. subobscura homozygous for such inversions shows, however, that D. madeirensis has a gene arrangement different from any known for D. subobscura. These results provide evidence for a greater differentiation of the X chromosome in these species than has previously been described; it seems that the X chromosome is the only one that has undergone structural variation during the speciation process.

Animals↗
PubMed1981

Ureido-ethyl-imidazolines active against autochtonous diethylnitrosamine-induced epidermoid, papillary and adenocarcinomatous tumors of the respiratory tract of Syrian hamsters and against human bronchogenic carcinomas in nu/nu mice.

The detection of a new class of tumor inhibiting substances is described. Employing a chemical reaction discovered several years ago, a series of imidazolinylureas were prepared. It was found that some compounds of this group were active against diethylnitrosamine (DENA)-induced tumours in hamsters. CGP 15720 A (1-[2-[2-(4-pyridyl)-2-imidazoline-1-yl]-ethyl]-3-(4-carboxy-phenyl)urea. Xb), the most active compound at present, was developed through a series of structural variations. CGP 15720 A inhibits significantly in oral or parenteral treatment with well tolerated doses (10-30 mg/kg) the progressive growth of autochthonous, DENA-induced papillary, epidermoid and adenocarcinomatous tumors of the respiratory system in Syrian hamsters and prolongs significantly the survival. The substance also inhibits significantly the growth of 2 poorly differentiated human epidermoid or anaplastic bronchogenic carcinomas in nu/nu Balb/c mice and prolongs the mean survival time. In these mice, the substance is also active against the rodent ascites tumors Ehrlich carcinoma, CrSa 180 and Yoshida Sa AH 66, although it is only marginally active or inactive against these tumors in normal mice or rats.-In the therapeutic trials, hamsters tolerated the highest dose administered for 4 weeks, 1000 mg/kg p.o., without signs or symptoms of toxicity.

Animals↗
PubMed1987

The mediastinum in sagittal sectioning. Anatomy and magnetic resonance imaging (MRI).

Ten volunteers with a normal mediastinum were investigated by magnetic resonance using a 0.5 Tesla CGR imager with a supraconducting magnet. The reconstruction matrix consisted of a 256 X 256 grating for a field of the order of 420 mm, with a spatial resolution of 1.6 X 1.6 mm2. The sections, balanced in T1, were performed in synchronization with the ECG. The successive sagittal sections were correlated with sagittal sections made on a single embalmed frozen subject. The MRI and anatomic sections were made at 5 mm intervals and located in relation to the median sagittal plane of the mediastinum. Examples of structural variations, malformations or tumours studied in sagittal sections, and taken from investigation of over 170 patients, demonstrate the importance of this investigational technique.

Electrocardiography↗
PubMed1996

Wild chromosomal variants in Aspergillus nidulans.

Pulsed-field gel electrophoresis and a chromosome-specific cosmid DNA library were used to determine the karyotypes of wild-type Aspergillus nidulans isolates from around the world. Overall, little structural variation was found, with a few major exceptions. One isolate possessed a non-essential B-chromosome of about 1.0 million base pairs (mb). Another isolate had undergone a non-reciprocal translocation of about 1.6 mb of chromosome VI onto chromosome VIII. Other than these chromosomal differences, these isolates appeared phenotypically normal. To analyze its effects on meiosis, the translocation isolate was outcrossed with another wild-type derivative that had a normal electrophoretic karyotype. This cross produced a range of phenotypes, including duplicated progeny that had a barren phenotype similar to that described for Neurospora partial disomics. The duplication was somewhat vegetatively unstable. This is the first association of sterility with chromosomal duplication in A. nidulans.

Aspergillus nidulans↗
PubMed1995

Side-chain oxysterol regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity.

Side-chain oxysterols are known to be potent inhibitors of 3-hydroxy-3-methylglutaryl CoA reductase, a key regulatory enzyme in the biosynthesis of sterols. Structural variations in the side-chain oxysterols influence enzyme inhibition. Under certain conditions, biological systems have been induced to produce side-chain oxysterols, adding support to the hypothesis that oxysterols may be natural regulators of sterol biosynthesis in the intact cell. Specific inhibition of sterol biosynthesis is of interest as it may prove useful in the prevention or reversal of various cardiovascular disease states, as well as in the control of normal and abnormal cell growth.

Animals↗
PubMed1992

Functional capacity of Fc gamma receptor III (CD16) on human neutrophils.

Receptors for the Fc region of immunoglobulin G (IgG) are a structurally diverse group of molecules. Within the three Fc gamma R families (Fc gamma RI, Fc gamma RII and Fc gamma RIII), the presence of distinct genes and alternative splicing variants leads to a variety of receptor isoforms that are most strikingly different in the transmembrane and intracellular regions. An obvious example of structural variation in the transmembrane and cytoplasmic domains is observed in the Fc gamma RIII family. Fc gamma RIIIB, which is nearly identical to Fc gamma RIIIA in the extracellular domains, lacks both transmembrane and cytoplasmic protein domains and is anchored to the cell through a glycosyl phosphatidylinositol anchor. Analysis of Fc gamma RIII function presents a considerable challenge in understanding the role of different Fc gamma R receptors in polymorphonuclear neutrophil (PMN) function. While one hypothesis for the role of Fc gamma RIII in Fc gamma R-dependent PMN effector functions is that Fc gamma RIII serves as a binding molecule which focuses the IgG ligand for more efficient recognition and intracellular signaling by Fc gamma RII, recent observations from a number of laboratories suggest that Fc gamma RIII on PMN can transduce signals across the membrane independent of ligand-dependent engagement of Fc gamma RII. We will review these data and present recent data which suggest that the role of Fc gamma RIII extends beyond direct initiation of functions to a more complex role of synergistic receptor interactions. These findings will be reviewed in the context of the experimental approaches that have been used to examine the roles of Fc gamma RII and Fc gamma RIII on PMN function.

Antibodies, Monoclonal↗
PubMed1996

MRI of anatomical variants of the wrist in women.

In the analysis of magnetic resonance (MR) images of the wrist joint, some structural variations may lead to misinterpretation. Our aim was to search for different anatomical variants and their MR characteristics on axial images. Two groups of patients with rheumatoid arthritis (thirty one) and carpal tunnel syndrome (sixty two), and a group of asymptomatic controls (fifty four) underwent bilateral MR axial wrist imaging from the metacarpal bases to the distal radiocarpal joint. The imaging techniques included spin echo (SE), turbo spin echo (TSE) and fast field echo (FFE) sequences, using 3 mm-slice thickness. Different anatomical variants including hypoplasia of the hamulus or hook of the hamate bone (4 cases), anomalous muscles (lumbricals) inside the carpal tunnel (2 cases), unusual location (5 cases) and double branching of the median nerve (14 cases), and aberrant median artery (one case) were detected. These variants, if unfamiliar to MR readers, may be misinterpreted as pathological features.

Adolescent↗
PubMed2000

[Oxcarbazepine (Trileptal). An effective and well tolerated new drug as first choice in treatment of focal seizures].

Oxcarbazepin (OXC; 10,11-dihydro-10-oxo-5H-dibenz-[b,f]azepin-5-carboxamid, trade name Trileptal) is a new antiepileptic drug for treatment of mono- and adjunctive therapy of partial seizures with or without secondary generalization for adults and children above 6 years of age. It was developed through structural variation of carbamazepine. Extensive postmarketing use includes more than 200,000 patient years. The mechanism of action mainly involves blockage of sodium currents. The recommended daily starting dose of oxcarbazepin for both mono- and adjunctive treatment is 8-10 mg/kg (600 mg/day for adults) in two doses and can be titrated according to clinical benefit up to 2400 mg/day. Oxcarbazepin undergoes reductive metabolism at its keto moiety to form MHD, which is glucuronidated and excreted in the urine, with minimal involvement of the hepatic cytochrome P450-dependent enzymes. Thus, OXC has limited drug interactions and does not require slow titration, allowing for better tolerability. Oxcarbazepin compares favorably to presently available new anticonvulsants of the second generation for two reasons: it is available immediately for both mono- and adjunctive therapy in adults and children, and extensive postmarketing experience from many countries is already available. In addition, OXC has been thoroughly tested in an unusually large clinical development program and been shown to be similarly effective as standard antiepileptic drugs.

Adult↗