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PubMed1974

Transcription of DNA from the 70S RNA of Rous sarcoma virus. I. Identification of a specific 4S RNA which serves as primer.

The enzymatic transcription of DNA from the 70S RNA of Rous sarcoma virus (RSV) is initiated on the 3' terminus of a molecule of 4S RNA which is hydrogen bonded to the viral genome. We labeled this primer with radioactive deoxynucleotides, and demonstrated that its release from 70S RNA by thermal denaturation was accompanied by a reduction in the template activity of the viral RNA. Two-dimensional electrophoresis in polyacrylamide gels separated the 4S RNAs associated with the 70S RNA of RSV into approximately eight fractions, each of which appeared to contain a discrete species of tRNA. The RNA in one of these fractions served as the principal primer for initiation of DNA synthesis by both detergent-disrupted virions of RSV and purified RNA-directed DNA polymerase with RSV 70S RNA as template.

Avian Sarcoma Viruses↗

PubMed2004

Effect of irbesartan versus atenolol on left ventricular mass and voltage: results of the CardioVascular Irbesartan Project.

Regression of hypertensive left ventricular hypertrophy (LVH) is associated with improved prognosis. The aim of this trial was to compare the effects of irbesartan versus atenolol on LVH in subjects with essential hypertension. Because electrocardiographic and echocardiographic parameters of LVH carry disparate prognostic information, both methods were applied in this trial. In the randomized, double-blind, multicenter trial CardioVascular Irbesartan Project, 240 patients with essential hypertension were treated with irbesartan or atenolol for 18 months. Voltage criteria used for LVH were Sokolow index, Cornell index, Cornell voltage x QRS duration product and Lewis index. In parallel, left ventricular mass (LVM) was determined by 2-dimensional guided M-mode echocardiography. After 6 and 18 months, reductions of LVM and voltage criteria for LVH were only found in subjects treated with irbesartan. However, a reduction of LVM was only detectable in subjects within the highest quartile of baseline LVM but not overall. In contrast, reductions of voltage criteria for LVH were detectable after 6 and 18 months even within commonly used normal limits. In conclusion, treatment of hypertension with irbesartan resulted in a significant reduction in the voltage criteria for LVH, although an effect on LVM was only seen in subjects with high baseline LVM. In contrast, atenolol did not lead to reductions in electrocardiographic or echocardiographic parameters of LVH. Because voltage criteria for LVH have been shown to predict cardiovascular outcome independently from LVM, we suggest that both methods should be used to accurately assess the benefits of antihypertensive treatment.

Adrenergic beta-Antagonists↗

PubMed1988

The DSM-III-R personality disorders: an overview.

The revision of DSM-III (DSM-III-R) includes substantial changes in the axis II personality disorders. The authors present and critically review these revisions and suggest directions for further research. The issues discussed include the multiaxial system, the use of a categorical rather than a dimensional format, the change from monothetic to polythetic criteria sets, the reduction in overlap among criteria sets, the decrease in the amount of unnecessary inferential clinical judgment required to make diagnoses, and the addition of two new personality disorders in an appendix. The criteria sets for many of the DSM-III personality disorders were also substantially revised in DSM-III-R. Changes in each of these are discussed in turn.

Humans↗

PubMed2004

Inhibition of matrix metalloproteinase-9 reduces in vitro invasion and angiogenesis in human microvascular endothelial cells.

The expression of matrix metalloproteinases (MMPs), particularly MMP-9, is significantly increased during tumor progression and is thought to play a major role in mediating angiogenic process. Since microvasculature plays an important role in controlling tumor growth, we investigated the effects of MMP-9 inhibition on endothelial cell migration and tube formation, two determinants of angiogenesis. Adenoviral-mediated MMP-9 downregulation inhibited endothelial cell migration in cell wounding and spheroid migration assays. To determine the effects of MMP-9 reduction in glioblastoma/endothelial co-cultures, we used a three-dimensional co-culture assay of glioblastoma spheroids and endothelial spheroids. Untreated controls showed invasion of both cell populations into each other whereas treatment of the co-cultures with adenoviral antisense MMP-9 particles resulted in reduced invasion. Next, inhibition of MMP-9 by adenoviral vectors in endothelial cells was assessed for in vitro capillary-like structure formation either by co-culture with glioblastoma cells or exposure to glioblastoma-conditioned medium. Addition of conditioned medium from human glioblastoma cells to endothelial cells treated with antisense MMP-9 adenoviral vectors or co-cultures of glioblastoma cell lines with MMP-9-reduced endothelial cells resulted in reduced capillary-like tube formation demonstrating the key role of MMP-9 in endothelial cell network organization. Examination of in vitro capillary-like tube structure formation using Matrigel showed a significant decrease in MMP-9 downregulated endothelial cells as compared to controls. In conclusion, the inhibition of MMP-9 is required for inhibition of endothelial cell migration and tube formation and is likely to be of importance in cerebral angiogenesis for therapeutic targets.

Adenoviridae↗

PubMed1988

Biosynthesis and secretion of laminin and laminin-associated glycoproteins by nonmalignant and malignant human keratinocytes: comparison of cell lines from primary and secondary tumors in the same patient.

Laminin biosynthesis was compared in four pairs of human squamous cell carcinoma cultures derived from primary and recurrent or metastatic tumors in four patients with cancer of the larynx and hypopharynx to determine if changes in laminin production accompany tumor progression. Laminin profiles of the malignant cells were compared with laminin biosynthesized by nonmalignant human keratinocytes. Pulse-chase biosynthetic labeling of the cultures with [35S]methionine established that all of the squamous carcinoma cell lines synthesize immunoreactive A (Mr 400,000), B1 (Mr 205,000), and B2 (Mr 200,000) laminin subunits; assemble them to form the intact laminin molecule (Mr 950,000); and secrete a portion of the laminin they produce into the culture media. One aspect of laminin expression unique to keratinocytes, both malignant and nonmalignant, was the occurrence of three additional glycoprotein forms (Mr 195,000, 170,000, and 160,000) in the laminin immunoprecipitates. In contrast to the laminin subunits, these glycoproteins were not immunoreactive with the anti-laminin antiserum on Western blots. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis without and with reduction of disulfide bonds revealed that the laminin immunoprecipitates contained a family of oligomeric molecules. These ranged in apparent molecular weight from 370,000 to 950,000 and were composed of laminin subunits and the glycoprotein forms linked by interchain disulfide bonds. The malignant keratinocyte cell lines from different patients were distinguishable in terms of the array of laminin and glycoprotein forms displayed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the rate of [35S]methionine incorporation into laminin during the pulse-labeling, the fraction of [35S]methionine-labeled laminin secreted into the medium during the chase incubation, and the absolute amount of laminin secreted into the culture medium as determined by enzyme-linked immunosorbent assay. However, cell lines established from primary and metastatic or recurrent cancer in the same patient were indistinguishable in their profile of laminin biosynthesis and secretion. In comparison to primary cultures of nonmalignant foreskin basal keratinocytes, the malignant cells secreted into the culture medium a larger fraction of the laminin that they produce. This is an indication that the malignant keratinocytes in culture deposited a less stable basal lamina-like extracellular matrix than their malignant counterparts. The diminished integrity of the basal lamina matrix may be an important factor in the invasive growth of human epithelial cancer.

Carcinoma, Squamous Cell↗

PubMed1993

[The transcatheter closure of the persistent ductus arteriosus in an adult].

Transcatheter closure of a patent ductus arteriosus was successfully performed in a symptomatic 48-year-old man. Pulmonary to systemic flow ratio was of 2.8:1 and ductus arteriosus closure was carried out percutaneously, using a 17 mm. Rashkind umbrella. One month later, the patient presented a significant clinical improvement and there also was a reduction of the left ventricle dilatation, objectively assessed by two-dimensional echocardiography.

Aortography↗

PubMed1996

[Structure of O-specific polysaccharide from Proteus mirabilis O10, containing a new component of O-antigens--L-altruronic acid].

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Proteus mirabilis O10 and studied after full acid hydrolysis and carboxyl reduction by 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear 1H,13C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY). It was found that the polysaccharide contains 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-galacturonic acid, and L-altruronic acid, and the following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: [sequence: see text]

Carbohydrate Conformation↗

PubMed1980

Double one-dimensional electrophoresis of human serum transferrin: a new high-resolution screening method for genetically determined variation.

With one-dimensional electrophoresis or electrofocusing the selective demonstration of proteins and their genetically determined variants from complex compositions like the physiological body fluids often is possible only with specific staining techniques or immunofixation. By the method described here samples are separated by PAG electrophoresis and a selected detail of the electropherogram is further resolved by PAG electrofocusing. The resulting pattern of bands after a usual protein stain can easily be interpreted due to the reduction of the number of bands. Informative bands hidden in a one-dimensional pherogram by overlapping with one or more other bands can be selectively visualized by the one-dimensional combination of two electrophoretic methods. With the double one-dimensional technique several hundred samples can be analyzed per person day. Thus the application in electrophoretic screening studies appears to be of special interest. The method is demonstrated by using the polymorphism of human serum transferrin as an example. A new variant of Tf-C with a high incidence in the German population is demonstrated.

Adult↗

PubMedDate not supplied

Traumatic atlanto-occipital luxation in a dog: associated hypoglossal nerve deficits and use of 3-dimensional computed tomography.

OBJECTIVE: To present a detailed description of a dog with atlanto-occipital (A-O) luxation, including results of the neurologic examination, diagnostic imaging, and treatment by closed reduction. STUDY DESIGN: Clinical case report. SAMPLE POPULATION: One adult intact male German shepherd dog. RESULTS: Neurologic signs included nonambulatory tetraparesis and neck pain. An apparent hypoglossal nerve deficit was consistent with a lesion at the peripheral part of the nerve in the region of the craniocervical junction. Radiographic examination revealed a left-sided luxation of the A-O joint, and fractures were excluded with the aid of computed tomography (CT). Closed reduction of the luxated articulation resulted in a stable A-O joint, and complete neurologic recovery occurred within 4 weeks. CONCLUSIONS: Hypoglossal nerve deficits may be associated with A-O luxation. CLINICAL RELEVANCE: Closed reduction of a unilateral, traumatic luxation of the A-O joint is a therapeutic option in dogs. CT imaging, especially 3-dimensional reconstruction, was considered helpful in excluding fractures as well as defining treatment options.

Animals↗

PubMed1997

[Acromio-humeral distance and acromial shape in 3-dimensional computerized tomography reconstruction. Side comparison in supraspinatus outlet syndrome].

Mechanical irritations of the supraspinatus tendon due to a reduction of the subacromial space are considered to be a potential cause of supraspinatus outlet syndrome. The aim of the current study was, therefore, to provide a method of improved measurement of the acromiohumeral distance and the evaluation of the acromial shape. In seven patients aged 50-60 years with unilateral supraspinatus outlet syndrome, imaging with standardized, high-resolution computed tomography (CT) was performed in order to demonstrate the acromion and the subacromial space three-dimensionally. The acromiohumeral distance was measured in three reconstructed frontal sections, and the two sides of each patient were directly compared. The acromial shape was compared with the classification of Bigliani as derived from conventional radiography. Whereas the Constant Score was found to be significantly reduced in the diseased shoulders (p < 0.01), the acromiohumeral distance was not significantly lower in three standardized frontal sections. In five cases the classification of the acromial form from the conventional radiograph was confirmed by 3D CT, whereas in two cases it was shown to be different. Our results suggest that primary or secondary changes of the acromial form can be more accurately evaluated with 3D CT than with conventional radiography. A direct comparison of the two sides in patients with supraspinatus syndrome does not suggest a reduction of acromiohumeral distance in the diseased shoulder.

Female↗

PubMed2001

[Radiosurgery of cerebral arteriovenous malformations: target definition strategy].

BACKGROUND AND PURPOSE: Description and critical review of our procedure of definition of the target of irradiation of a cerebral arteriovenous malformations. PATIENTS: and method. Fixation of the stereotactic frame, performing of stereotactic angiography and CT scanner were described, and the target including nidus and venous collectors of the a cerebral arteriovenous malformations defined. CONCLUSION: The use of several three-dimensional imaging techniques can improve and simplify the method of delineating target with a reduction of radio-induced complications.

Cerebral Angiography↗

PubMed1977

A two-dimensional thin layer chromatographic procedure for the sequential analysis of oligonucleotides employing tritium post-labeling.

Two dimensional PEI-cellulose thin layer chromatography can resolve sequentially degraded oligonucleotide fragments of tRNA. This technique entails the sequential degradation of the oligonucleotide with snake venom phosphodiesterase in the presence of bacterial alkaline phosphatase, and periodate oxidation followed by tritiated sodium borohydride reduction of the 3' terminal nucleoside. Subsequently the tritiated oligonucleotide fragments were resolved by two dimensional PEI-cellulose TLC. The results of these experiments indicate that, in some cases, the complete nucleotide sequence of a large oligonucleotide fragment may be determined by interpretation of the observed mobility shifts, thereby eliminiating the need for additional analysis of the oligonucleotide. In addition, the use of two-dimensional rather than one-dimensional resolution of the tritium labeled fragments allows for a complete separation of any interfering background spots from the sequentially degraded oligonucleotides. This procedure was applied to the complete nucleotide sequence analysis of several ribonuclease T1Val and ribonuclease A digestion products from human placenta tRNA.

Base Sequence↗

PubMed2001

Three-dimensional finite element analysis of stress in the periodontal ligament of the maxillary first molar with simulated bone loss.

The purpose of the study was to use the finite element method to simulate the effect of alveolar bone loss on orthodontically induced stress in the periodontal ligament of the maxillary first molar. A 3-dimensional finite element model of a tooth with different levels of bone height was constructed to estimate the reduction in force and the increase in moment to force (M/F) ratio necessary to obtain evenly distributed stress in the periodontal ligament of a tooth with horizontal bone loss. The 3-dimensional finite model comprised a maxillary first molar, the periodontal ligament, and alveolar bone and consisted of 3097 nodes and 2521 elements. An anterior force of 300 g was applied at the center of the buccal crown surfaces of teeth with normal bone height and with bone loss that ranged from 2.0 to 6.0 mm. The results showed that force magnitude required lowering from 80% (2-mm bone loss) and gradually to 37% (6-mm bone loss) of the initial load applied to the tooth without bone loss. The countertipping moment (gram-millimeters) to force (gram) ratio should increase from 9 (no bone loss) to nearly 13 (6-mm bone loss) to maintain the same range of stress in the periodontal ligament as was obtained without bone loss. A linear relationship was observed between the amount of bone loss, the desired reduction in force magnitude, and the increase in M/F ratio. The results of this study indicate that a combination of force reduction and increased M/F ratio is required to achieve uniform stress in the periodontal ligament of a tooth with bone loss.

Alveolar Bone Loss↗

PubMed2004

Hearing thresholds during Gz acceleration with masking noise.

BACKGROUND: Future fighter aircraft will include three-dimensional sound signals as part of the human-machine interface. The reduction in cerebral vascular flow associated with maneuvering acceleration (+Gz) may affect a pilot's ability to perceive and interpret such aural cues. We hypothesized that vascular deprivation along the cochlea produced by +Gz would raise hearing thresholds either globally or specifically at 1000 Hz. METHODS: We compared hearing thresholds for pure tones at 250, 1000, 6000 and 10,000 Hz during exposure to +1 Gz vs. +4 Gz. Experiments were conducted with steady noise input to the earphones to mask centrifuge noise. RESULTS: Paradoxically the hearing threshold was slightly yet significantly reduced for 1000 Hz (53 dB at 1 G vs. 47 dB at 4 G) while remaining unchanged at other frequencies. DISCUSSION: Audition did not change at +4 Gz, contradicting our hypothesis. We infer that the change at 1000 Hz is not a central effect, but instead represents a disturbance of middle ear transmission mechanisms. The absence of any general hearing loss at +4 Gz favors the possibility of using complex sounds such as three-dimensional sound in aeronautical human-machine interfaces during acceleration.

Acceleration↗

PubMed1998

High-density recording and topographic analysis of the auditory oddball event-related potential in patients with schizophrenia.

BACKGROUND: Prior research has shown reductions of the N1, N2, and P300 auditory event-related potential (ERP) components in schizophrenic patients. Most studies have shown a greater P300 reduction in left versus right temporal leads in schizophrenic patients. These studies were done with sparse electrode arrays, covering restricted areas of the head, thus providing an incomplete representation of the topographic field distribution. METHODS: We used a 64-channel montage to acquire auditory oddball ERPs from 24 schizophrenic patients and 24 controls subjects. The N1, P2, N2, P300, and N2 difference (N2d) amplitudes and latencies were tested for group and laterality differences. Component topographies were mapped onto a three-dimensional head model to display the group differences. RESULTS: The schizophrenic group showed reduction of the N1 component, perhaps reflecting reduced arousal or vigilance, but no N1 topographic difference. An N2d was not apparent in the schizophrenic patients, perhaps reflecting severe disruption in neural systems of stimulus categorization. In the patients, the P300 was smaller over the left temporal lobe sites than the right. CONCLUSIONS: The increased ERP spatial sampling allowed a more complete representation of the dipolar nature of the P300, which showed field contours consistent with neural sources in the posterior superior temporal plane.

Adult↗

PubMed1999

Manometric analysis of anal sphincter damage after ileal pouch-anal anastomosis.

A constant reduction in anal sphincter pressure follows an ileoanal pouch procedure for ulcerative colitis and familiar adenomatous polyposis. We analyzed whether this reduction is more likely due to neurogenic damage or to direct sphincter trauma. Three-dimensional vector volume manometry was performed in 75 patients prior to the ileoanal pouch procedure and 3 months thereafter. Resting pressure was significantly reduced from 83.5 +/- 24.4 to 58.1 +/- 18.0 mmHg and squeezing pressure from 204.7 +/- 63.3 to 173.4 +/- 50.6 mmHg. Moreover, significant vector volume reductions were recorded postoperatively, and the asymmetry index increased significantly (resting: 11.5 +/- 4.1% to 18.4 +/- 7.4%; squeezing: 9.6 +/- 3.1 to 13.0 +/- 6.7%). Functional anal sphincter length at the high-pressure zone remained unchanged. Thus, there was no local damage to proximal or distal anal sphincter segments, which suggests that the postoperative impairment of sphincter function is secondary to neurogenic rather than morphological damage.

Adenomatous Polyposis Coli↗

PubMed2004

Conceptual and numerical model of uranium(VI) reductive immobilization in fractured subsurface sediments.

A conceptual model and numerical simulations of bacterial U(VI) reduction in fractured subsurface sediments were developed to assess the potential feasibility of biomineralization at the fracture/matrix interface as a mechanism for immobilization of uranium in structured subsurface media. The model envisions flow of anaerobic groundwater, with or without acetate as an electron donor for stimulation of U(VI) reduction by dissimilatory metal-reducing bacteria (DMRB), within mobile macropores along a one-dimensional flow path. As the groundwater moves along the flow path, U(VI) trapped in the immobile mesopore and micropore domains (the sediment matrix) becomes desorbed and transferred to the mobile macropores (fractures) via a first-order exchange mechanism. By allowing bacterial U(VI) reduction to occur in the mesopore domain (assumed to account for 12% of total sediment pore volume) according to experimentally-determined kinetic parameters and an assumed DMRB abundance of 10(7) cells per cm3 bulk sediment (equivalent to 4 mg of cells per dm3 bulk sediment), the concentration of U(VI) in the macropore domain was reduced ca. 10-fold compared to that predicted in the absence of mesopore DMRB activity after a 6-month simulation period. The results suggest that input of soluble electron donors over a period of years could lead to a major redistribution of uranium in fractured subsurface sediments, converting potentially mobile sorbed U(VI) to an insoluble reduced phase (i.e. uraninite) in the mesopore domain that is expected to be permanently immobile under sustained anaerobic conditions.

Adsorption↗

PubMed1996

Three-dimensional structure of meso-diaminopimelic acid dehydrogenase from Corynebacterium glutamicum.

Diaminopimelate dehydrogenase catalyzes the NADPH-dependent reduction of ammonia and L-2-amino-6-ketopimelate to form meso-diaminopimelate, the direct precursor of L-lysine in the bacterial lysine biosynthetic pathway. Since mammals lack this metabolic pathway inhibitors of enzymes in this pathway may be useful as antibiotics or herbicides. Diaminopimelate dehydrogenase catalyzes the only oxidative deamination of an amino acid of D configuration and must additionally distinguish between two chiral amino acid centers on the same symmetric substrate. The Corynebacterium glutamicum enzyme has been cloned, expressed in Escherichia coli, and purified to homogeneity using standard biochemical procedures [Reddy, S. G., Scapin, G., & Blanchard, J. S. (1996) Proteins: Structure, Funct. Genet. 25, 514-516]. The three-dimensional structure of the binary complex of diaminopimelate dehydrogenase with NADP+ has been solved using multiple isomorphous replacement procedures and noncrystallographic symmetry averaging. The resulting model has been refined against 2.2 A diffraction data to a conventional crystallographic R-factor of 17.0%. Diaminopimelate dehydrogenase is a homodimer of structurally not identical subunits. Each subunit is composed of three domains. The N-terminal domain contains a modified dinucleotide binding domain, or Rossman fold (six central beta-strands in a 213456 topology surrounded by five alpha-helices). The second domain contains two alpha-helices and three beta-strands. This domain is referred to as the dimerization domain, since it is involved in forming the monomer--monomer interface of the dimer. The third or C-terminal domain is composed of six beta-strands and five alpha-helices. The relative position of the N- and C-terminal domain in the two monomers is different, defining an open and a closed conformation that may represent the enzyme's binding and active state, respectively. In both monomers the nucleotide is bound in an extended conformation across the C-terminal portion of the beta-sheet of the Rossman fold, with its C4 facing the C-terminal domain. In the closed conformer two molecules of acetate have been refined in this region, and we postulate that they define the DAP binding site. The structure of diaminopimelate dehydrogenase shows interesting similarities to the structure of glutamate dehydrogenase [Baker, P. J., Britton, K. L., Rice, D. W., Rob, A., & Stillmann, T.J. (1992a) J. Mol. Biol. 228, 662-671] and leucine dehydrogenase [Baker, P.J., Turnbull, A.P., Sedelnikova, S.E., Stillman, T. J., & Rice, D. W. (1995) Structure 3, 693-705] and also resembles the structure of dihydrodipicolinate reductase [Scapin, G., Blanchard, J. S., & Sacchettini, J. C. (1995) Biochemistry 34, 3502-3512], the enzyme immediately preceding it in the diaminopimelic acid/lysine biosynthetic pathway.

Amino Acid Oxidoreductases↗