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Biomedical subjects

D Giacherio

Publications and source records attributed to D Giacherio.

11 recordsLinked to original sources
PubMed1989

Treatment of Wilson's disease with zinc. V. Changes in serum levels of lipase, amylase, and alkaline phosphatase in patients with Wilson's disease.

We noted a frequent increase in the serum enzymes amylase, lipase, and alkaline phosphatase in patients with Wilson's disease who are receiving zinc acetate therapy (25 or 50 mg elemental zinc three times daily). Typically, values are normal before the initiation of zinc therapy, increase to slightly above normal after a few weeks of therapy, and stabilize at the high normal range after approximately a year of treatment. Very large dosages of zinc (800 mg/day) produce even further elevation of serum lipase and amylase without the symptoms of pancreatitis. Pancreatic pathologic studies of a zinc-treated rat model receiving dosages equivalent to up to 25 times the effective dosage in a human being, which is based on milligrams of zinc per kilogram of body weight, reveal that no lesions are induced by zinc treatment in the pancreas. We interpret these findings to indicate that extended maintenance therapy with zinc does not pose a risk of pancreatic damage in patients with Wilson's disease.

Adolescent↗
PubMed1986

A high performance liquid chromatographic assay for tocainide with alternate application for the determination of lidocaine, procainamide, and N-acetylprocainamide.

We describe a simple, isocratic high-performance liquid chromatographic method for measuring the oral antiarrhythmic agent tocainide in serum. The extraction requires 200 microliters of serum, is performed on a reverse-phase column, and utilizes the drug mepivacaine as the internal standard. This analytical method can also be used to assay procainamide, n-acetylprocainamide, or lidocaine with minor modifications to either the extraction protocol or the wavelength used to monitor column eluant.

Acecainide↗
PubMed1986

Liquid-chromatographic analysis for cyclosporine with use of a microbore column and small sample volume.

This liquid-chromatographic assay requires 0.2 to 0.5 mL of whole blood, avoids the use of diethyl ether, and consumes only 10 to 20% of the solvents used in prior methods. Sample preparation involves an acidic extraction with methyl-t-butyl ether, performed in a 13 X 100 mm disposable glass tube, then a short second extraction of the organic phase with sodium hydroxide. After evaporation of the methyl-t-butyl ether, chromatography is performed on an "Astec" 2.0-mm (i.d.) octyl column. We compared results by this procedure with those by use of earlier larger-scale extractions and their respective 4.6-mm (i.d.) columns; analytical recoveries of cyclosporins A and D were comparable with previous findings and results for patients' specimens were equivalent, but the microbore columns provided greatly increased resolution and sensitivity.

Chromatography, Liquid↗
PubMed1984

Simultaneous determination of penicillin and cephalosporin antibiotics in serum by gradient liquid chromatography.

We describe a "high-performance" liquid-chromatographic method for simultaneously measuring various penicillin and cephalosporin antibiotics. After extraction from serum, which in general is quantitative, the drugs are separated by use of a "Bondapak phenyl" column and a gradient mobile phase. For these drugs retention times depend on the pH of the mobile phase; we present retention times under selected pH conditions.

Anti-Bacterial Agents↗
PubMed1980

A specific DNA unwinding activity associated with SV40 large T antigen.

The incubation of highly purified large T antigen with relaxed, circular SV40 DNA in the presence of topoisomerase I (nicking closing enzyme) resulted in the introduction of negative superhelical turns in the DNA. ATP was not required for this reaction. A similar introduction of superhelical turns could also be obtained when a recombinant plasmid DNA (Y182), which contains sequences from both SV40 DNA and pBR322, was used. However, no effect was observed when relaxed pBR322 DNA, which does not contain SV40 DNA sequences, was incubated with T antigen in the presence of topoisomerase. These results are consistent with the hypothesis that large T antigen can recognize and unwind specific sequences on SV40 DNA.

Antigens, Neoplasm↗
PubMed1979

A poly(dT)-stimulated ATPase activity associated with simian virus 40 large T antigen.

Highly purified SV40 large T antigen exhibits an ATPase activity which can be stimulated approximately 7-fold by the DNA homopolymer poly(dT). The poly(dT)-stimulated enzyme can hydrolyze various ribonucleotide and deoxyribonucleotide triphosphates, with ATP and dATP serving as the best substrates. Purified large T antigen hydrolyzes ATP to ADP and Pi, with a maximum specific activity of 13.5 mumol of inorganic phosphate released per h per mg of protein. Of the various natural and synthetic polynucleotides tested, poly(dT) was by far the best activator. Long chain poly(dT) molecules are much more effective activators than are short chain length oligo(dT) molecules. The highly purified large T antigen contains no detectable protein kinase activity.

Adenosine Triphosphatases↗
PubMed1979

Single strand DNA binding of simian virus 40 tumor antigen.

Simian virus 40 T antigen binds to both single and double strand DNA. The single and double strand DNA binding activity of crude T antigen preparations was evaluated by chromatography of the antigen on DNA-cellulose columns. Crude T antigen was retained on both native and denatured DNA-cellulos columns and was eluted from both columns under similar conditions. The interaction of highly purified T antigen with single and double strand DNA was evaluated by competition experiments using a DNA filter binding assay. These experiments showed that T antigen binds preferentially to single strand calf thymus DNA by more than an order of magnitude when compared to double strand calf thymus DNA.

Antigens, Neoplasm↗
PubMedDate not supplied

False-positive results with chemically modified anti-D do not indicate a need to use a separate, immunologically inert Rh control reagent.

Thirteen of 1450 (0.9%) Rh-negative samples submitted for pretransfusion or prenatal testing gave weak false-positive reactions in immediate-spin (IS) tests with chemically modified anti-D (CM-D). Only seven reacted in control tests with anti-A and/or -B. The other six samples could have been considered Rh positive; however, such a conclusion is inappropriate, since stronger (greater than or equal to 3+) reactions are expected in IS tests with CM-D and the vast majority of true Rh-positive blood samples. Moreover, three of the six false-positive CM-D reactions associated with negative control tests were from patients previously found to be Rh negative. The other three samples gave 1+ to 2+ reactions with CM-D and did not react with anti-A and/or -B; these erroneous CM-D reactions were recognized by confirmatory tests with high-protein anti-D and Rh control reagents that were performed because previous typing results were not on file. Such confirmation, as well as careful grading and proper interpretation of serologic reactions, serves to prevent erroneous Rh typing without the use of a separate, immunologically inert Rh control reagent.

Blood Grouping and Crossmatching↗