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Biomedical subjects

M Gordon

Publications and source records attributed to M Gordon.

At least 505 records · Page 28Linked to original sources
PubMed1967

Studies on bile acids: The microquantitative separation of cellular bile acids by gas-liquid chromatography.

1. A method is described for the quantitative isolation of bile acids from cellular material. Homogenates of rat liver are freeze-dried and extracted exhaustively with 95% (v/v) ethanol containing 0.1% (v/v) of aq. ammonia (sp.gr. 0.88) and purified by anion-exchange chromatography on Amberlyst A-26. 2. The extracted bile acid conjugates are subjected to either of two hydrolytic procedures, one involving chemical and the other enzymic agents. A unique feature in this study is the introduction of an enzyme, a clostridial peptide-bond hydrolase, for the rapid cleavage of bile acid conjugates, replacing the classical drastic chemical hydrolysis with strong alkali. 3. After hydrolysis, free bile acids are methylated and converted into their trifluoroacetates for final determination by gas-liquid chromatography on a triple component column, FS-1265-SE30-NGS. 4. For the purpose of identification of peaks, bile acid methyl esters are converted into their trimethylsilyl ethers by allowing the methyl esters to react with a new and potent silyl donor, bis(trimethylsilyl)acetamide. 5. The technique affords us a means of studying the metabolism of bile acids at the cellular and subcellular levels in tissues.

Journal Article↗
PubMed1966

Differential inhibitory effects of actinomycin D among strains of poliovirus.

Schaffer, Frederick L. (University of California, Berkeley), and Marjorie Gordon. Differential inhibitory effects of actinomycin D among strains of poliovirus. J. Bacteriol. 91:2309-2316. 1966.-Actinomycin D exerted a differential effect on the ability of strains of poliovirus to replicate in HeLa cells. LSc-2ab was studied as an example of a strain markedly inhibited by actinomycin; MEF(1) served as a control strain with minimal inhibition. The effect was noted at an actinomycin concentration of 0.1 mug/ml, but 2.5 mug/ml was used for most studies. Variability in the effect was attributed, in part, to physiological factors. Actinomycin was effective when present during the first 2 hr of LSc infection, but had little effect if present at later times. It did not block adsorption or initiation of ecilpse. It did block synthesis of ribonucleic acid in LSc-infected cells. Several possible modes of action are discussed, the most attractive being that actinomycin blocks synthesis of some cell component, the concentration of which is more critical for replication of some poliovirus strains than others.

Adsorption↗
PubMedDate not supplied

Risk factors favoring the development of glaucomatous visual field loss in ocular hypertension.

Multivariate studies have identified elevated IOP, optic disc abnormality, increasing age, and a family history of glaucoma as risk factors for the development of glaucomatous visual field loss. Further studies are required to validate these findings and to identify additional risk factors. Eventually it may be possible to develop an equation capable of predicting accurately the risk of glaucoma developing in a given individual with ocular hypertension. If a reliable estimate of risk were available, rational decisions concerning the institution of therapy could be made.

Age Factors↗
PubMedDate not supplied

Effects of 6-hydroxydopamine on shock-elicited aggression, emotionality and maternal behavior in female rats.

Tests of emotionality and shock-elicited aggression, which have revealed consistent changes in behavior in male rats given 6-hydroxydopamine (6-OHDA), were administered to female rats intraventricularly injected with 250 mug of 6-OHDA to determine whether aspects of the 6-OHDA syndrome are shared by female and male rats. The results confirmed that female rats become hyperemotional as well as hyperaggressive after 6-OHDA, as do males. Using the hypothesis that the behavioral effects of 6-OHDA lesions of catecholamine neurons result from a general reduction in threshold to aversive stimuli, it was predicted that arbitrarily selected stimuli having aversive components should enhance the behavior normally elicited by these stimuli. Stimuli selected for testing were those that normally elicit maternal defensive aggression and maternal retrieval. Both of these behaviors were found to be enhanced in 6-OHDA treated female rats, thus supporting the prediction. These findings were interpreted as inconsistent with the hypothesis that norepinephrine chemically codes specific behaviors, particularly aggressive behavior.

Aggression↗
PubMedDate not supplied

Influence of tidal volume, respiratory rate, and supplemental oxygen flow on delivered oxygen fraction using a mouth to mask ventilation device.

We examined the influence of the following parameters in determining the FiO2 delivered to a pediatric lung model using the mouth-to-mask method of resuscitation: rate of ventilation, inspiratory tidal volumes, and supplemental oxygen flow. With a ventilator rate of 20/min and tidal volumes (Vt) < or = 100 mL, an FiO2 of approximately .50 was observed with a supplemental oxygen flow of 5 L/min. Increasing the supplemental oxygen flow to 15 L/m did not appreciably increase the FiO2 (FiO2 = .53 versus FiO2 = .60, respectively), but did cause a significant and unintended increase in Vt. Similar results were noted with a ventilator rate of 12/min and Vt < or = 100 mL (FiO2 = .68 versus FiO2 = .73, respectively). We also observed a potentially hazardous situation involving the positioning of the supplemental oxygen port that might result in high inspiratory pressures (stacking of breaths) to the pediatric patient. We believe additional testing is warranted prior to widespread use of this device in children.

Child↗
PubMedDate not supplied

Intrahippocampal LPS injections reduce Abeta load in APP+PS1 transgenic mice.

Multiple lines of evidence indicate that inflammatory processes are involved in the pathogenesis of Alzheimer's disease. Lipopolysaccharide (LPS) is widely used to induce inflammation in experimental systems. Consequently we injected LPS or saline intrahippocampally in 11 and 16 months old APP+PS1 transgenic mice to induce brain inflammation, then used immunocytochemistry to examine amyloid pathology 7 days later. As expected, LPS activated microglia as indicated by a significant increase in the area covered by major histocompatibility complex-II (MHC-II) immunostaining in the mice injected with LPS compared to the saline injected. Simultaneously, Abeta immunostaining showed an unexpected reduction of the Abeta load in the mice injected with LPS compared to the saline injected. This effect of LPS on the Abeta load in APP+PS1 mice strengthens the hypothesis that moderate amounts of microglial activation may be beneficial in Alzheimer's disease, by increasing the clearance of Abeta.

Amyloid beta-Peptides↗
PubMedDate not supplied

Acute arterial occlusions of the small vessels of the hand and forearm: treatment with regional urokinase therapy.

PURPOSE: Arterial occlusions of the small vessels of the forearm and hand may have the same consequences as arterial occlusions in the distal lower extremity. There is limited reported experience with the regional thrombolytic therapy in this setting. The authors reviewed their experience with thrombolytic therapy in acute and subacute arterial occlusions of the distal upper extremity to further clarify its role. MATERIALS AND METHODS: Twelve patients with acute or subacute arterial occlusions of the forearm and hand who had ischemic digits and were treated with regional urokinase infusion were identified retrospectively. Their medical and radiology records were reviewed. RESULTS: All 12 patients demonstrated angiographic improvement and 11 patients demonstrated clinical improvement after treatment. Tissue necrosis in four patients led to partial amputation of one digit in two patients and three digits in two patients. Three of these patients had category III ischemia at presentation. The level of resulting amputation was altered in all but one patient. Vasospasm was noted frequently but responded to vasodilators. No significant complications occurred. CONCLUSIONS: When therapeutic alternatives are limited to anticoagulation and expectant amputation, regional urokinase infusion can optimize distal runoff, obviate or improve the options for distal surgical bypass, and limit tissue loss.

Acute Disease↗