PURPOSE: Current sonographic technology has enhanced imaging. This study analyzes the sonographic findings in a large series of patients with pancreatic ductal adenocarcinoma. METHODS: The sonograms of 62 patients with pathologically confirmed pancreatic ductal adenocarcinoma were retrospectively analyzed. RESULTS: Tumors were an average of 4.5 x 3.5 cm in cross section. The largest lesion was 14.0 x 9.0 cm, and the smallest was 1.8 x 1.1 cm. Forty-three tumors (69%) were located in the head of the pancreas, 1 (2%) at the junction of the head and body, and 16 (26%) in the body or tail; 2 lesions (3%) were diffuse. Tumors were ovoid or spherical in 37 patients (60%) and irregular in 25 (40%). Forty tumors (65%) markedly deformed the shape of the gland. Six lesions (10%) caused no glandular contour abnormality and were visualized only because tumor echogenicity differed from that of the normal pancreas. Thirty-four tumors (55%) were homogeneously hypoechoic compared with the normal pancreas, 2 (3%) were homogeneously hyperechoic, 1 (2%) was isoechoic, and 25 (40%) had heterogeneous echotextures. Many of the heterogeneous tumors were predominantly hypoechoic with areas of varied echogenicity. Calcifications were noted in 4 patients (6%) and small intratumoral cystic areas in 9 patients (15%). Postobstructive pseudocysts were found in 4 patients (6%). Color Doppler flow information was available for 19 patients; internal flow was detected in only 1 tumor (5%). Vascular occlusion was found in 3 patients and circumferential vascular encasement in 8; the tumors in these patients were unresectable. Tumors were noted to touch vessels in another 6 patients. CONCLUSIONS: Current sonographic equipment allows the demonstration of new findings in pancreatic carcinoma. Color Doppler sonography can define tumor involvement of blood vessels and potentially affect clinical staging and treatment decisions.

Blood Flow Velocity↗

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A model for individual supervision in a general hospital.

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Hospitals, General↗

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Preparation and applications of peptide-oligonucleotide conjugates.

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Amino Acid Sequence↗

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Preparation of oligonucleotide-peptide conjugates.

A procedure for preparing oligonucleotide-peptide conjugates is presented. It is based on appending a maleimide group to the oligonucleotide for selective coupling to the thiol side chain of a cysteine residue in the peptide. A convenient chromatographic purification procedure, based on Fmoc-on/Fmoc-off, is described.

Amino Acid Sequence↗

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Protected thiol-polyethylene glycol: a new activated polymer for reversible protein modification.

Monomethoxypolyethylene glycol (mPEG) of average molecular weight 5000 was transformed in a series of synthetic steps to a new activated form of PEG, a stable thiol-protected intermediary, for reaction with cysteine residues in proteins under mild conditions to produce PEG--protein conjugates as possible candidates for therapeutics. The modified protein has PEG polymer molecules attached to the backbone by the newly formed disulfide bonds, which are readily cleaved to regenerate the native protein under mild reducing conditions. The model protein papain, which has seven cysteine residues including a lone cysteine in its active site, was modified through the free available thiol. The resulting PEG--papain was characterized by matrix-assisted laser desorption mass spectrometry, SDS-PAGE, and high performance gel filtration chromatography. The major modified PEG--papain variant was demonstrated to be 5000 Da larger than the unreacted papain.

Chromatography, Gel↗

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Preparation of vitamin B6-conjugated peptides at the amino terminus and of vitamin B6-peptide-oligonucleotide conjugates.

A series of N-(4'-pyridoxyl)peptides has been made by standard Fmoc chemistry and a solid-phase coupling procedure. The last Fmoc group of the peptide was removed on the synthesizer, and the free amino group was then condensed with pyridoxal. The Schiff base formed was selectively reduced using sodium cyanoborohydride. The product was cleaved from the resin using a standard procedure. No deleterious effects were found when using the protected amino acids Fmoc-L-Ala, Fmoc-L-Arg(Pmc), Fmoc-L-Asp(OtBu), Fmoc-L-His(Trt), Fmoc-L-Ser(tBu), Fmoc-L-Thr(tBu), and Fmoc-L-Cys(Trt) for peptide synthesis. A vitamin B6-peptide-oligonucleotide conjugate could be synthesized using a cysteinyl peptide and a suitably activated oligonucleotide.

Amino Acid Sequence↗

PubMedDate not supplied

Synthesis of oligoarginine-oligonucleotide conjugates and oligoarginine-bridged oligonucleotide pairs.

Conjugates consisting of oligoarginine peptides linked to oligodeoxynucleotides have been synthesized, including a new type of conjugate, in which a pair of oligonucleotides is bridged by a cationic peptide. Two different 9-mer oligonucleotides were conjugated to the terminal cysteine residues of the peptide series H-Cys-(Arg)n-Cys-NH2 (n = 3, 5, 7). Different thiol protecting groups were utilized on the amino- and carboxy-terminal cysteine residues of the peptide to allow selective attachment to the 3'- or 5'-terminus of each specific oligonucleotide. The conjugates containing oligoarginine peptides were purified by anion-exchange chromatography, and their structures were confirmed by polyacrylamide gel electrophoresis and amino acid analysis.

Amino Acid Sequence↗

PubMedDate not supplied

Dual-specificity interaction of HIV-1 TAR RNA with Tat peptide-oligonucleotide conjugates.

An oligonucleotide-peptide conjugate, having dual binding capability for a designated RNA, was designed. The peptide portion of the conjugate interacts with a folded domain in the RNA, whereas the oligonucleotide portion hybridizes with a nearby single-stranded region in the RNA. The dual specificity was proven in a model HIV-1 TAR RNA system using an RNase H cleavage assay to assess antisense binding to this RNA. The peptide portion of the conjugate was shown to confer increased specificity on the oligonucleotide.

Amino Acid Sequence↗