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Biomedical subjects

J Taboury

Publications and source records attributed to J Taboury.

At least 19 recordsLinked to original sources
PubMed1996

[Non-vascular retroperitoneal emergencies].

Acute renal disease, in the absence of trauma, consist of acute renal obstruction, renal infection or a combination of the two. The diagnosis of acute renal colic is usually performed with ultrasound or excretory urography whereas parenchymal involvement in renal infection is best demonstrated on computed tomography images. The aim of radiologic investigations is to look for complications in order to guide the treatment, particularly percutaneous procedures. Other less common acute renal diseases include renal vein thrombosis optimally analyzed with contrast injection to demonstrate renal function, and spontaneous renal hemorrhage, which implies careful renal assessment looking for a small tumor. Acute psoas compartment diseases include hematomas and abscesses. Computed tomography is the best diagnostic tool and the examination of choice for the follow-up lesions and to guide percutaneous drainage.

Acute Disease↗
PubMed1996

[Imaging of symptomatic giant hemangioma].

A case of symptomatic giant hemangioma of the liver with fever, anemia, and increased erythrocyte sedimentation rate is reported. Spontaneous hyperdense areas at CT, and high signal-intensity areas at T1-weighted MR images were demonstrated within the hemangioma. Marked hemorrhagic zones demonstrated at pathologic examination may explain these uncommon clinical and imaging features.

Adult↗
PubMed1995

[Ultrasonography of the tendons of the rotator cuffs of the shoulder].

After a short review of the use of ultrasonography to study shoulder rotator tendons, the technique of the investigation is described, as well as the main landmarks, findings indicative of complete rotator cuff tear, and limitations of ultrasonography in this indication. A number of issues concerning the preoperative workup are discussed. Results in a prospective study of 100 patients are reported. Findings upon ultrasonography, arthrography, and surgical exploration in these patients are analyzed comparatively. Sensitivity and specificity of ultrasonography for the diagnosis of complete rotator cuff tear (RCT) were 95% and 100%, respectively. These data show that ultrasonography is a reliable investigation for confirming, detecting, and evaluating RCT, although extensive experience with the technique is required.

Arthrography↗
PubMed1992

[Ultrasonography of the shoulder: diagnosis of rupture of tendons of the rotator muscles].

After a short historical review of the use of ultrasonography to study shoulder rotator tendons, the technique of the investigation is described, as well as the main landmarks, findings indicative of complete rotator cuff tear, and limitations of ultrasonography in this indication. A number of issues concerning the preoperative workup are discussed. Results in a prospective study of 24 patients are reported. Findings upon ultrasonography, arthrography, and surgical exploration in these patients are analyzed comparatively. Sensitivity and specificity of ultrasonography for the diagnosis of complete rotator cuff tear (RCT) were 95% and 100%, respectively. These data show that ultrasonography is a reliable investigation for confirming, detecting, and evaluating RCT, although extensive experience with the technique is required.

Arthrography↗
PubMed1986

NMR, CD and IR spectroscopies of a tridecanucleotide containing a no-base residue: coexistence of B and Z conformations.

The synthesis of the tridecadeoxynucleotide d(CGm5CGCGxACATGT), where x is the 1-cyano-2-deoxy-beta-D-erythropentofuranose, is described. The NMR, IR, CD studies at various salt concentrations and temperatures of this oligomer show that the B and Z conformations are simultaneously present in the same short DNA fragment. A single apurinic residue is sufficient for the coexistence of the B and Z helices on this oligomer.

Base Sequence↗
PubMed1984

1H NMR and circular dichroism studies of the B and Z conformations of the self-complementary deoxyhexanucleotide d(m5C-G-C-G-m5-C-G): mechanism of the Z-B-coil transitions.

The double-helical conformations of d(m5-C-G-C-G-m5-C-G) in aqueous solution were studied by circular dichroism and 1H NMR spectroscopy. In 0.1 M NaCl, only the B form is detected whereas the Z form is strongly predominant in 3 M NaCl. In the presence of 2 M NaCl, two resonance signals corresponding to the B and Z duplexes were observed for each proton below 50 degrees C, indicating a slow exchange between B and Z. However, the B-Z exchange becomes intermediate or fast in the 55-80 degrees C temperature interval. By contrast the exchange between B helix and single-stranded (or coil) forms is much faster for the same temperature conditions. The Z form is only detectable when the coil form is practically absent. With decreasing temperature the B form decreases in favor of the Z form. From proton line-width measurements under various experimental conditions, it was also shown that Z exchanges only with B, while the latter also exchanges with the single-stranded form (S): Z in equilibrium B in equilibrium S. The enthalpy value is about 8 +/- 1 kcal/mol for the B-Z transition and about 40 +/- 2 kcal/mol for the B-S dissociation (2 M NaCl solution). The activation energy is about 47 +/- 2 kcal/mol for the Z----B and 39 +/- 2 kcal/mol for the B----Z reaction. Very good agreement between the experimental results and computed data (based on the above kinetic reaction model) was found for the B, Z, and coil proportions. The B-Z transition of methylated d(C-G)n oligomers is only possible when the Watson-Crick hydrogen bonds between the CG base pairs are firmly maintained; otherwise, the transformation from B to Z would not occur, and B-S dissociation would take place instead.

Circular Dichroism↗
PubMed1984

B,Z conformations and mechanism of the Z-B-coil transitions of the self-complementary deoxy-hexanucleotide d(C-G-m5C-G-C-G) by 1H-NMR and CD spectroscopy.

The helical structures of d(C-G-m5C-G-C-G) were studied in aqueous solution at various salt concentrations and temperatures by CD and 1H-NMR spectroscopy. At room temperature only the B form is observed in 0.1 M NaCl whereas the B and Z forms are simultaneously present in 1.8 M NaCl. At high salt concentration (4 M NaCl) the Z form is largely predominant (greater than 95%). The Z form proton resonances were assigned by using the polarisation transfer method (between B and Z at 1.8 M NaCl) and by proton-proton decoupling (at high salt concentration). The Z-B-Coil transitions were studied as a function of temperature with the 1.8 M NaCl solution. At high temperature (95 degrees C) only the coil form (S) is present. Below 55 degrees C the coil proportion is negligible, and the B-Z exchange is slow. The disappearance of the coil gives rise at first to the B form and on lowering the temperature the Z proportion increases to the detriment of the B form. Proton linewidth, relaxation and polarisation transfer studies confirm the conclusion in the previous report on d(m5C-G-C-G-m5C-G) (Tran-Dinh et al Biochemistry 1984 in the press) that Z exchanges only with B whereas the latter also exchanges with S,Z in equilibrium B in equilibrium S. The present data show that even at high salt concentration where only the Z form of d(C-G-m5C-G-C-G) is observed the Z-S transition also passes through the B form as an intermediate stage. The B-Z transition takes place when the Watson-Crick hydrogen bonds are firmly maintained and is greatly favoured when there are three hydrogen bonds between the base-pairs.

Circular Dichroism↗
PubMed1984

Z-form induction in DNA by carcinogenic nickel compounds: an optical spectroscopy study.

The B----Z conformational transition of double-stranded poly(dG-dC) induced by various nickel salts (chloride, sulfate, subsulfide, carbonate) has been studied by ultraviolet absorption and circular dichroism. The spectra of the nickel compounds, both free and complexed with DNA, have been obtained in the visible and near infrared regions. In all cases the nickel adopts the hexacoordinated ionic form [Ni(H2O6]2+ and induces the B----Z transition of the nucleic acid at submillimolar concentrations (typically 0.4 mM). The addition to the poly(dG-dC)-poly(dG-dC) of an antitumoral drug, pentaziridinocyclodiphosphathiazene (SOAz), inhibits the B----Z transition even at a ten-fold higher nickel concentration (4 mM). Possible implications for carcinogenesis are discussed.

Antineoplastic Agents↗