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Biomedical subjects

A Goswami

Publications and source records attributed to A Goswami.

101 records · Page 6Linked to original sources
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Consciousness and biological order: toward a quantum theory of life and its evolution.

Biological order is discussed within the context of the idealist interpretation of quantum mechanics. A quantum mechanism is proposed for quantum speciation and for quantum evolution, in general. It is shown that an extension of neo-Darwinism to include quantum evolution via a quantum mechanism can resolve some of the recent controversies that have rattled evolution theory. It is pointed out that the quantum approach has the further benefit of giving a straightforward insight into the nature of life itself. Experimental support for some aspects of the theory is discussed.

Biological Evolution↗
PubMedDate not supplied

Is there conscious choice in directed mutation, phenocopies, and related phenomena? An answer based on quantum measurement theory.

In a previous article (Goswami, 1997), it was suggested that an application of quantum measurement theory under the auspices of a monistic idealist ontology (that consciousness is the ground of being) can solve many difficult problems of neo-Darwinism, e.g., alternating rapid creativity and homeostasis observed in evolution and the directionality, origin, and nature of life. In this article, we propose an epigenetic quantum mechanism to explain the connection of developmental processes and evolution, as has been evidenced in such controversial phenomena as directed mutation and phenocopies.

Animals↗
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Antineoplastic agents, 88. Pimelea prostrata.

The aerial portion of Pimelea prostrata (Thymelaeaceae) collected in New Zealand was evaluated as a source of substances that inhibit growth of the murine P-388 lymphocytic leukemia (PS). Simplexin (1) and Pimelea factor P2 (2) were found to strongly inhibit growth (ED50 5 X 10(-3) and 8 X 10(-4) micrograms/ml, respectively) of the PS in vitro cell line. The cyclic orthoester (2) was also found to inhibit growth (T/C 132 at 20 micrograms/kg) of the PS in vivo system. Detailed 1H-nmr (at 400 MHz) and 13C-nmr studies combined with fast atom bombardment mass spectral evidence were employed to confirm the structural assignments.

Animals↗
PubMedDate not supplied

Antineoplastic agents, 99. Amaryllis belladonna.

Amaryllis belladonna bulbs were examined for constituents inhibitory against the murine P-388 lymphocytic leukemia (PS system). Two in vitro active alkaloids, acetylcaranine (2; 9PS ED50 0.23 microgram/ml) and ambelline (3; 9PS ED50 1.6 micrograms/ml), were isolated accompanied by undulatine. However, the non-chiral anhydrolycorinium chloride (5) was found to be the principal antineoplastic (3 PS, 64-69% life extension at dose levels 10 to 20 mg/kg in vivo, ED50 1.4 micrograms/ml in vitro) component. Quaternary chloride 5 has not been located previously among plant or animal biosynthetic products.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

Antineoplastic agents, 103. The isolation and structure of hypoestestatins 1 and 2 from the East African Hypoëstes verticillaris.

The East African shrub Hypoëstes verticillaris representing a heretofore chemically unexplored. Acanthaceae genus has been found to contain two new cell growth inhibitory (murine P-388 lymphocytic leukemia) phenanthroindolizidine alkaloids termed hypoestestatin 1 (1a) and hypoestestatin 2 (1b). Both substances were found to markedly inhibit growth of the murine P-388 cell line (ED50 = 10(-5) micrograms/ml). The structures of hypoestestatins 1 and 2 were assigned primarily on the basis of results from extensive spectral studies.

Alkaloids↗
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Leurosine biotransformations: an unusual ring-fission reaction catalyzed by peroxidase.

The dimeric Vinca alkaloid leurosine undergoes an unusual fission of the piperidine ring of the Iboga substructure when reacted with horseradish peroxidase and hydrogen peroxide. A preparative-scale oxidation of leurosine provided 15'-hydroxycatharinine, which was identified by infrared and proton and carbon-13 NMR spectroscopies and high-resolution mass spectrometry. A proposed pathway for the formation of 15'-hydroxycatharinine involves radical and iminium intermediates and cleavages of a putative diol. The enzymatic transformation product is 3 orders of magnitude less active than leurosine or vinblastine in vitro, in inhibiting the polymerization of tubulin.

Animals↗
PubMedDate not supplied

Effect of sampling frequency on EMG power spectral characteristics.

During digitization of surface EMG, the signal is converted by an Analog-to-Digital (A/D) convertor at a specific sampling rate. This sampling rate should be selected cautiously because a high rate may include noise signals and a low rate may lead to errors. The present study was undertaken to show the effect of sampling rate on EMG power spectrum. The study was carried out on nine subjects and EMG record was done from deltoid muscle at sampling rates of 4, 6, 8 and 10 KHz during maximal voluntary contraction. Biopotential coupler with a response range of 5 Hz to 2 KHz was used during recording of the EMG signal which was processed later by Fast Fourier Transform software. The study showed a linear relationship between the sampling rate and the mean power frequency (MPF). But there was no distinct effect of sampling rate on mean and root mean square (RMS) of the digitized signal.

Adolescent↗