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Biomedical subjects

S K Shukla

Publications and source records attributed to S K Shukla.

At least 37 records · Page 2Linked to original sources
PubMed1994

An activity gel assay for the detection of DNA helicases and nucleases from cell-free extracts.

An activity gel assay was developed for the detection of DNA helicases in crude extracts. The assay was based on the ability of DNA helicases to unwind radioactive fragments from single-stranded M13 circles that were immobilized in an SDS polyacrylamide gel. The displaced radioactive strands were detected by blotting them to a filter and visualizing the resulting bands by autoradiography. Experiments with purified proteins demonstrated that DNA helicases, endonucleases and exonucleases could produce activity bands. A one-dimensional gel assay was sufficiently sensitive to allow detection of DNA helicase I, DNA helicase II, DNA helicase IV, the RecQ helicase as well as 3 unidentified putative DNA helicases in crude extracts of Escherichia coli. Exonuclease and endonuclease activities from crude extracts could be distinguished from DNA helicase activities by their ATP-independence and from each other by their band morphologies.

Base Sequence↗
PubMed1993

Diagnostic significance of T I < T III and TV1 > TV6 signs in ischaemic heart disease.

One hundred seventy patients with ischaemic heart disease (IHD) and 141 healthy controls were evaluated to assess the diagnostic significance of T I < T III and TV1 > TV6 as compared to widening of QRS-T angle. Number of cases with abnormal widening of QRS-T angle was significantly higher (P < .001) in frontal and horizontal planes in the IHD group. T I < T III sign has 61.2% sensitivity, 74.5% specificity and 25.5% false positivity in diagnosis of IHD. Along with abnormal QRS-T angle widening it gave a specificity of 95.5% but a false positivity of 35% and a low sensitivity index (35.3%). TV1 > TV6 sign has sensitivity, specificity and false positivity of 72.9% 84.4% and 15.6% respectively. Combining it with abnormally wide QRS-T angle did not materially improve these indices. Combining T I < T III and TV1 > TV6 signs gives a sensitivity of 49.4%, specificity of 95% and false positivity of 5% in IHD. This is a good diagnostic index and can be assessed at a quick glance without cumbersome estimation of QRS-T angle.

Electrocardiography↗
PubMed1993

[The effect of ethylenediaminetetramethylenephosphonate on the biodistribution of tumor-seeking radionuclides].

It is well known that after application of radioactive complexes for tumour diagnosis or therapy, such as 67Ga-citrate or radiolanthanide complexes (167Tm- or 169Yb-nitrilotriacetate, -citrate, -alpha-hydroxyisobutyrate, 90Y-citrate, etc.) activity is accumulated not only in the tumour but also in other organs, above all liver and bone. This is the main obstacle to their medical use. Recently published results encouraged us to use ethylenediaminetetramethylene phosphonate (EDTMP) for the reduction of extratumoural liver activity. The results show that even small amounts of EDTMP (1-2 mg/kg BW) reduce the activity deposition in the liver by about one order of magnitude. EDTMP provoked elimination of activity from tumour, skeleton and other tissues but not to the same extent as from the liver. Tumor/liver activity ratios > 5 are achievable in this manner.

Animals↗
PubMed1993

[The effect of bone-seeking metal salts on the biodistribution of tumor-seeking heavy metal complexes].

This work attempted to overcome the problem of unwanted bone radioactivity after injection of tumour-affine heavy-metal compounds (prototype 169Yb-citrate) by pre-application of stable yttrium- and calcium-compounds into tumour-bearing mice in doses of 1 mg metal/kg body weight. The pre-application of stable yttrium and calcium resulted in a smaller bone radioactivity. The most favourable results were achieved by injecting the metal salts simultaneously at or within 5 h before the 169Yb-citrate. On the other hand a strong radioactivity increase in the RES (liver and spleen) by a factor of 2 to 4 was observed after yttrium-preapplication.

Animals↗
PubMed1993

[Long term biokinetics of 169Yb following injection as citrate, hydroxyethylethylenediaminetetraacetate and nitrilotriacetate].

169Yb complexes with known biokinetics in tumour-bearing mice up to 48 h p.i. were injected into healthy mice to study the radionuclide biodistribution in various organs and tissues for 672 h after injection, in order to obtain reliable biokinetic data in an animal model, not affected by tumour-growth, as a basis for the calculation of biological half-life and dose distribution. The results demonstrated the existence of at least two components with different biological half-lives in the organs and tissues investigated. The effective half-lives of these components decreased with increasing stability of the complexes administered. The effective half-life of the fast component was a few hours and that of the slow one between about 200 and 800 h.

Animals↗
PubMed1992

[The effect of Ca-diethylenetriamine pentaacetate on the bio-behavior of tumor-affine metal complexes].

The complexon CaDTPA was injected into tumour-bearing mice in concentrations of 0.05, 0.1, 0.3, and 0.6 mole/l (pH:6) 30 min after the 169Yb-injection. 100 microliters of a 0.3 M CaDTPA solution were injected at different time points (simultaneously, 2, 5, 10, 20, 30, 40 and 50 min, 1, 1.25, 1.5, 2.5 and 10 h) after 169Yb-citrate injection. The animals were killed 24 h after radionuclide administration. A strong radioactivity decrease was observable 24 h p.i. not only in blood, liver, spleen, muscle and bone but also in the tumour if CaDTPA was administered within the first 2 h after ytterbium injection. Thereafter no change in radioactivity could be achieved by DTPA. A time phase in which the Yb could be eliminated from the tissues by means of DTPA (time intervals < 2 h) was distinguishable from a time phase in which it was not attainable for DTPA (time intervals > 5 h). This indicates that the incorporation of Yb into the cells is completed after 5 h and that the metals are intracellularly bound, probably to the lysosomes. Improvements of the scintigraphic tumour detection cannot be expected from the use of complexons.

Animals↗
PubMed1990

Capillary zone electrophoresis in pharmaceutical analysis.

The paper presents a brief characterization of capillary zone electrophoresis, a modern analytical separation method with high expediency for practical applications, especially in pharmaceutical analysis. Basic theoretical considerations are presented and discussed to explain the effects of the operational parameters upon the separation efficiency and resolution of species. Descriptions of simple instrumentation and of the analytical procedure itself are given. Experimental examples are given of the separation of mixtures of pharmaceutically important compounds and of the effects of operational parameters, especially pH of BGE and voltage applied. Lastly, the practical application of CZE for analysis of isoxsuprine in commercial preparations is shown.

Electrophoresis↗
PubMed1989

Dermatitis artefacta.

Dermatitis artefacta is an uncommonly encountered condition. This paper presents a case report of two such rare patients. The symptomatology and history of fourteen and sixteen year old males with dermatitis artefacta are described. Possible psychophysiological aetiology of the cases is discussed.

Adolescent↗
PubMed1979

Uptake of 67Ga-6-mercaptopurines in Morris hepatoma-3924 A.

67Ga-chloro-6-mercaptopurine and 67Ga-citrato-6-mercaptopurine complexes have been prepared and their distribution in Morris-hepatoma-3924 A-bearing rats studied. The tumour affinity of the gallium-67 compounds varies in the order: 67Ga-chloro-6-mercaptopurine greater than 67Ga-citrato-6-mercaptopurine greater than 67Ga-citrate greater than 67Ga-chloride.

Animals↗