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Biomedical subjects

M Gordon

Publications and source records attributed to M Gordon.

At least 307 records · Page 17Linked to original sources
PubMed1986

New issues in agricultural spraying in Israel.

Food and fiber production on relatively small, irrigated plots with high-yielding potential makes the agricultural aircraft a vital tool in Israel's modern agriculture. Extensive preventive measures are carried out to minimize chemical drift and to dispose of chemical wastes. The Civil Aviation Authority is concerned with both pilot fatigue and exposure to toxic chemicals and thus the legal limits of flight time and the medical monitoring methods are enforced. With the introduction of new pesticides, such as the pyrethroids, new medical monitoring methods must be developed. The tables show amounts and kinds of chemicals used on cotton since 1978 and the percentages of various insecticides used on cotton in 1979, 1981, and 1984. Since pyrethroids are of low, short-term mammalian toxicity, can we continue to apply them in increasing amounts without monitoring exposure? Past experience has taught us to treat any pesticide with caution. A method for monitoring exposure to pyrethroids should be introduced.

Aerospace Medicine↗
PubMed1986

Serum and peritoneal fluid proteins in women with and without endometriosis.

We examined the proteins in serum and peritoneal fluid of women with endometriosis (and of healthy controls) for evidence of an autoimmune response that might account for their impaired fertility. No antibodies against endometrial glycoproteins or against "progestin dependent endometrial protein" (PEP) were found in any serum or peritoneal fluid sample. Levels of PEP were not different in serum from women with moderate to severe endometriosis (n = 6), with mild endometriosis (n = 21), or from disease-free cycling controls (n = 19). PEP levels in peritoneal fluid from mild endometriosis and from controls did not differ but were elevated ten times in fluid obtained in the secretory phase from women with moderate to severe disease. This suggests that PEP levels in peritoneal fluid reflect the extent of ectopic endometrial growth. The salient finding was a heretofore undescribed protein (mol wt 70,000) in secretory phase peritoneal fluid samples (18/20) and its absence during the proliferative phase (0/35).

Ascitic Fluid↗
PubMed1986

Differential diagnosis of weakness--a common geriatric symptom.

Weakness can result from diuretics causing azotemia and hypokalemia, whereas psychotropic drugs are often implicated as a cause of impaired emotional and physical drive. Peripheral neuropathy may lead to weakness of limbs. In the elderly, common causes include diabetes mellitus and alcoholism.

Aged↗
PubMed1985

Transposon-like properties of the major, long repetitive sequence family in the genome of Physarum polycephalum.

A family of long, highly-repetitive sequences, referred to previously as ;HpaII-repeats', dominates the genome of the eukaryotic slime mould Physarum polycephalum. These sequences are found exclusively in scrambled clusters. They account for about one-half of the total complement of repetitive DNA in Physarum, and represent the major sequence component found in hypermethylated, 20-50 kb segments of Physarum genomic DNA that fail to be cleaved using the restriction endonuclease HpaII. The structure of this abundant repetitive element was investigated by analysing cloned segments derived from the hypermethylated genomic DNA compartment. We show that the ;HpaII-repeat' forms part of a larger repetitive DNA structure, approximately 8.6 kb in length, with several structural features in common with recognised eukaryotic transposable genetic elements. Scrambled clusters of the sequence probably arise as a result of transposition-like events, during which the element preferentially recombines in either orientation with target sites located in other copies of the same repeated sequence. The target sites for transposition/recombination are not related in sequence but in all cases studied they are potentially capable of promoting the formation of small ;cruciforms' or ;Z-DNA' structures which might be recognised during the recombination process.

Journal Article↗
PubMed1985

Two modes of amber codon read-through in vitro.

Read-through translation of bacteriophage R17 amB2 coat cistron carrying an amber mutation at the seventh codon was studied in vitro using the crude cell extract (S30) derived from an Escherichia coli nonsuppressor strain. Despite the presence of termination factors as well as ribosome-releasing factor (RRF) which prevent the read-through translation [M. Ryoji, J. W. Karpen, and A. Kaji (1981) J. Biol. Chem. 256, 5798-5801], synthesis of coat-like protein still persists at a low level in this system. Characterization of this protein by peptide fingerprinting and amino acid sequencing was performed to reexamine the generally accepted notion that it is produced by amino acid misinsertion to the amber mutation codon. The results indicated, however, that the major population of this coat-like protein is produced as a result of reinitiation of translation from the eighth codon. Read-through by amino acid misinsertion in this system becomes predominant only when the Mg2+ concentration is higher than 16 mM.

Cell-Free System↗
PubMed1985

Practice-based data set for a nursing information system.

It has been argued that nursing practice components are not sufficiently clarified to develop specifications for a nursing data set within an NIS. The purpose of this paper was to examine this assumption. Conclusions were drawn that both philosophically and conceptually, the components of practice are clear. In addition, a sufficient taxonomy for the content and structure of a data set is available. A draft of 17 items, categories, definitions, and rationale for inclusion is presented. Validity and reliability of the specified item-categories is discussed. As in any profession, work on the precision of patient descriptors and therapeutic interventions is ongoing. This work is greatly enhanced if a data set is computerized and the content and organization is consistent with practice components. Large-scale studies of item-categories can further refine the structure and organization of a nursing data set.

Computers↗
PubMed1985

Composite-veneered amalgam restorations.

A procedure is described for the construction of composite resin veneers for large amalgam restorations. The resulting restoration combines the physical qualities of amalgam with the esthetic benefits of composite resins. Among the 14 restorations that have been studied for 2 years, none failed mechanically and minor surface discolorations have been satisfactorily corrected by polishing.

Bicuspid↗
PubMed1985

The protective effect of prazosin on the ischaemic and reperfused myocardium.

Experiments were undertaken to establish whether prazosin prevents isolated hearts from gaining excess Ca2+ during post-ischaemic reperfusion, to determine whether this effect is dose-dependent, if it is accompanied by a change in the energy-rich phosphate reserves, and whether prazosin is effective when added only upon reperfusion. Isolated, spontaneously beating rat hearts were used. The ischaemic episodes ranged from 15 to 60 min, and prazosin (0.01 to 10 micro mol/1) was added both before inducing ischaemia and upon reperfusion. When 0.01 to 1 micro mol/1 prazosin was present before and after the ischaemic episode the reperfusion-induced gain in Ca2+ was attenuated, but not abolished. Pretreatment with 0.01 to 1 micro mol/1 prazosin slowed the ischaemic-induced rise in resting tension, enhanced mechanical recovery after 30 but not 60 min ischaemia, and exerted a dose-dependent slowing effect on the ischaemia-induced depletion of ATP and CP, with 1 micro mol/1 being the optimal dose. Adding 0.01 to 1 micro mol/1 prazosin at the time of reperfusion neither prevented excess Ca2+ accumulation upon reperfusion nor did it exert an energy-sparing effect. 5 to 10 micro mol/1 prazosin did not attenuate the reperfusion-induced gain in Ca2+, irrespective of whether it was added before or only at the time of reperfusion. These results show that the dose-response curve for the inhibitory effect of prazosin on Ca2+ overload is complex, and that adding prazosin coincident with the reperfusion of isolated ischaemic hearts does not attenuate Ca2+ gain.

Adenosine Triphosphate↗
PubMed1985

HTLV-III env gene products synthesized in E. coli are recognized by antibodies present in the sera of AIDS patients.

The envelope gene of HTLV-III, the retrovirus directly linked to AIDS, encodes a protein of 856 amino acids. Our sequence analysis of the cloned HTLV-III (HXB-3) env gene and its comparison with other isolates reveal significant divergence, especially in the external portion of this protein. A large segment of the env gene (1800 bp) was inserted into the expression vector pEV-vrf3, and a corresponding 68 kd protein, which encompasses both the extracellular and the membrane-associated regions of the native protein, was produced in E. coli. Several smaller polypeptides, which appear to be internal initiation products, were also produced. All 50 AIDS patient sera obtained from different locations in the United States specifically recognized the bacterially synthesized envelope proteins, as judged by Western blots. This suggests that these proteins will be useful for the diagnosis of HTLV-III infection and possibly as a vaccine against AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1985

The effect of C3H mouse mammary tumour on the levels of serum and urine analytes in vivo.

A study of C3H mice implanted with mammary tumours has shown that the levels of serum total protein, alanine transaminase and alkaline phosphatase are all lower than those found in normal mice, while aspartate transaminase is higher. Serum urea values were similar to normal levels, but creatinine was lower in males and higher in females. In the male mice, urine protein and urine N-acetyl-beta-D-glucosaminidase (NAG) activity were lower than in normal mice. Comparisons were made with age and sex matched controls which was found to be important for alkaline phosphatase, as this was shown to decrease with increasing age of the mice over the period from 10-30 weeks of age. The analyte values found in this study provide useful base-line data for assessing biochemical toxicity of cancer chemotherapy agents. It has been shown that some of these values can vary with age, or can be different if tumour-bearing mice are used instead of normal mice.

Acetylglucosaminidase↗
PubMed1985

Specific attachment of Agrobacterium tumefaciens to bamboo cells in suspension cultures.

Agrobacterium tumefaciens was tested for its ability to attach to tissue culture cells of bamboo, a monocotyledonous plant. Phase-contrast microscopy and kinetic experiments with radiolabeled bacteria showed that attachment to bamboo cells was indistinguishable from attachment to cells of dicotyledonous plants. Bacterial mutants defective in attachment to dicotyledonous plants showed similar behavior with bamboo, and extensive washing of the bamboo cells had no effect on the number of bacteria which attached.

Adhesiveness↗
PubMed1985

Limited-host-range plasmid of Agrobacterium tumefaciens: molecular and genetic analyses of transferred DNA.

A tumor-inducing (Ti) plasmid from a strain of Agrobacterium tumefaciens that induces tumors on only a limited range of plants was characterized and compared with the Ti plasmids from strains that induce tumors on a wide range of plants. Whereas all wide-host-range Ti plasmids characterized to date contain closely linked oncogenic loci within a single transferred DNA (T-DNA) region, homology to these loci is divided into two widely separated T-DNA regions on the limited-host-range plasmid. These two plasmid regions, TA-DNA and TB-DNA, are separated by approximately 25 kilobases of DNA which is not maintained in the tumor. The TA-DNA region resembles a deleted form of the wide-host-range TL-DNA and contains a region homologous to the cytokinin biosynthetic gene. However, a region homologous to the two auxin biosynthetic loci of the wide-host-range plasmid mapped within the TB-DNA region. These latter genes play an important role in tumor formation because mutations in these loci result in a loss of virulence on Nicotiana plants. Furthermore, the TB-DNA region alone conferred tumorigenicity onto strains with an intact set of vir genes. Our results suggest that factors within both the T-DNA and the vir regions contribute to the expression of host range in Agrobacterium species. There was a tremendous variation among plants in susceptibility to tumor formation by various A. tumefaciens strains. This variation occurred not only among different plant species, but also among different varieties of plants within the same genus.

DNA, Bacterial↗
PubMed1985

Effects of asbestos on the random migration of rabbit alveolar macrophages.

The toxicity of sized and characterized chrysotile, crocidolite, and amosite preparations obtained from Dr. K. R. Spurny have been evaluated using alveolar macrophage (AM) migration inhibition assays and viability tests. These results have been compared with asbestos samples obtained from the National Institute of Environmental Health Sciences (NIEHS). These latter samples are designated chrysotile A (RT), crocidolite (RT), and amosite (RT). In addition, filter-isolated preparations of chrysotile A (RT) that consisted mainly of large nonphagocytosable fibers were also tested. Chrysotile (Spurny) and sonicated chrysotile A (RT) produced 50% migration inhibition at about 115 micrograms/mL. Spurny crocidolite produced 50% migration inhibition at about 340 micrograms/mL, whereas RT crocidolite produced 50% migration inhibition at about 230 micrograms/mL. RT amosite caused 50% migration inhibition at about 180 micrograms/mL, whereas Spurny amosite was inactive up to 500 micrograms/mL. The large nonphagocytosable chrysotile A (RT) fibers produced 50% migration inhibition at about 66 micrograms/mL. This indicates that fibers can be toxic for AM through extracellular membrane contact. In general the results from the viability studies paralleled the migration inhibition observations. None of the asbestos preparations induced a burst in the hexose monophosphate shunt of BCG-immune AM at 1 mg/mL. BCG-immune AM were more susceptible to cell death than normal AM when incubated with chrysotile A (RT), amosite (RT) and zymosan. Migration inhibition induced by asbestos fibers probably reflects toxicity of the asbestos preparations and could play an important role in blocking normal alveolar clearance of inhaled particles.

Animals↗