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Biomedical subjects

A Kraszewski

Publications and source records attributed to A Kraszewski.

At least 37 records · Page 2Linked to original sources
PubMed1985

Energy deposition in a model of man in the near field.

The spatial distribution of the specific absorption rate (SAR) was measured in a full-scale model of man using implantable electric field probes. The model was exposed in the near-field of linear and aperture antennas at 350 MHz. Effects of the wave polarization, antenna position and antenna gain on the SAR distribution and the average SAR in the whole-body and body parts are reported.

Humans↗
PubMed1982

Dielectric properties of animal tissues in vivo at radio and microwave frequencies: comparison between species.

An improved and modified technique with an open-ended coaxial-line sensor was used for measurement of the dielectric properties of animal tissues in vivo. The permittivity of skeletal muscle, brain cortex, spleen and liver of live cats and rats was measured at frequencies between 0.1 and 10 GHz. The results were compared with various published data on in vivo permittivity of the same and other species. The differences between the properties of the same tissue for various animals are very small. The tissues properties at frequencies above 1 GHz correlate well with the water content. Practically all water in the skeletal muscle is in the free form, while in other tissues both free and bound water are present.

Animals↗
PubMed1981

Expression in Escherichia coli of a chemically synthesized gene for a "mini-C" analog of human proinsulin.

A gene has been constructed which codes for an analog of human proinsulin in which the normal 35-amino acid connecting peptide is replaced by a "mini-C" peptide of six amino acids (Arg-Arg-Gly-Ser-Lys-Arg). The gene, composed of oligonucleotide fragments synthesized by the triester method, was cloned and expressed as a beta-galactosidase hybrid protein. The proinsulin analog was separated from beta-galactosidase by cyanogen bromide cleavage and purified. Controlled disulfide exchange in the S-sulfonate of the analog generated a molecule having high-pressure liquid chromatography (HPLC) and radioimmunoassay (RIA) behavior consistent with a proinsulin-like structure.

Amino Acid Sequence↗
PubMed1980

The case of sulfonation in the chemical synthesis of oligonucleotides.

The sulfonation of nucleosidic component, a side reaction during phosphotriester bond formation, as a function of the reactivity of the condensing agents and the kind of substituents in the starting phosphodiester is discussed. It was found that in the coupling reaction of nucleoside alkyl phosphodiesters, the degree of sulfonation of the nucleosidic component was very high; while under the same conditions when the aryl group was present in the corresponding phosphodiester, this side reaction practically did not occur.

Arylsulfonates↗
PubMed1980

Prospective double-blind trial of synthetic steroid (Org OD 14) for preventing postmenopausal osteoporosis.

A double-blind trial of Org OD 14, a synthetic steroid with an unusual endocrine profile, was conducted on 100 postmenopausal women; of these, 63 completed two years' treatment (33 Org OD 14; 30 placebo). A dose of 2.5 mg/day successfully prevented bone loss over two years, whereas a significant reduction in bone mineral content occurred in women taking placebo, the rate being comparable to that in earlier studies (p less than 0.01). At the dosage used (2.5 mg/day) Org OD 14 also significantly reduced the severity of menopausal complaints (flushing, sweating, etc). Vabra aspiration curettage in 20 cases 6-18 months after starting active treatment showed no evidence of endometrial hyperplasia, though weak proliferation of the endometrium was seen in three. Org OD 14 may provide a new approach to hormonal prevention of bone loss in postmenopausal women without inducing appreciable endometrial stimulation; the potential value of Org OD 14 in osteoporosis and other post-climacteric complaints warrants further investigation.

Bone Resorption↗
PubMed1980

Further studies on oligoribonucleotide synthesis.

Recent results concerning the synthesis of oligoribonucleotides via the phosphotriester method, such as functionalization of ribonucleosides, new phosphorylating agents, 5'-O-sulfonylation and chromatography on Sephadex LH-20 for monitoring the removal of internucleotide phosphotriester groups, are presented. To show that efficiency of a new approach to the synthesis of oligoribonucleotides the pentamer /Up/4U was obtained.

Esters↗
PubMed1979

Bone loss during oestriol therapy in postmenopausal women.

In contrast to all other oestrogens examined thus far oestriol hemisuccinate (12 mg/day) did not prevent bone loss in 28 postmenopausal women. The average bone loss, however, was somewhat less than expected from placebo studies, while the bone loss achieved by a group taking 4-6 mg/day was equal to that achieved by previous placebo groups. To be an effective agent for prevention of post-menopausal osteoporosis oestriol would have to be prescribed in daily doses considerably in excess of 12 mg.

Adult↗
PubMed1979

Expression in Escherichia coli of chemically synthesized genes for human insulin.

Synthetic genes for human insulin A and B chains were cloned separately in plasmid pBR322. The cloned synthetic genes were then fused to an Escherichia coli beta-galactosidase gene to provide efficient transcription and translation and a stable precursor protein. The insulin peptides were cleaved from beta-galactosidase, detected by radioimmunoassay, and purified. Complete purification of the A chain and partial purification of the B chain were achieved. These products were mixed, reduced, and reoxidized. The presence of insulin was detected by radioimmunoassay.

Amino Acids↗
PubMed1978

Bone response to termination of oestrogen treatment.

Forty-three oophorectomised patients were reviewed 8 years after their initial attendance at a research clinic investigating the aetiology and prevention of postmenopausal osteoporosis. Fifteen patients who had been treated with an oestrogen did not lose a significant amount of bone during the 8 years of therapy. Patients in the placebo-treated control group initially had bone loss of 2.6% per annum, which later fell to an average of 0.75% per annum. Fourteen patients who had been treated with oestrogen for the first 4 years lost no bone, but on withdrawal of oestrogen their bone mineral content fell over the next 4 years at an average rate of 2.5% per annum. 8 years after their initial attendance there was no significant difference between this group and patients who had received placebo for the full 8 years. The result of this study indicates that long-term prevention of bone loss by oestrogens has important medical, social, economic implications.

Bone and Bones↗