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Biomedical subjects

R T Jones

Publications and source records attributed to R T Jones.

At least 289 records · Page 16Linked to original sources
PubMed1977

On the tryptic peptides from hemoglobin chains of six carnivores.

The amino acid compositions of the tryptic peptides of the following carnivore hemoglobin chains have been determined: gray fox (Urocyon cineroargenteus); raccoon (Procyon lotor); polar bear (Thalarctos maritimus); coati mundi (Nasua nasua) beta chain; coati mundi (Nasua narica) two beta chains; cat (Felis catus) alpha chain; and lion (Pantbera leo) beta chain. These provide a basis for future sequencing of these hemoglobins and construction of an evolutionary tree. The specific results are summarized in the following article (Stenzel and Brimhall, 1977).

Amino Acid Sequence↗
PubMed1977

Prolonged delta-9-tetrahydrocannabinol ingestion. Effects of sympathomimetic amines and autonomic blockades.

In order to evaluate the possible effects of delta-9-tetrahydrocannabinol (THC) on autonomic nervous system function, cardiovascular responses to intravenous isoproterenol, phenylephrine, atropine, and propranolol were compared in hospitalized volunteers before and after 14 days of THC ingestion. There was no significant alteration in responses to isoproterenol or phenylephrine, although in one subject the pressor effect of phenylephrine was considerably augmented by THC. Heart rates after parasympathetic (atropine) blockade and after combined parasympathetic and sympathetic (propranolol) blockade were significantly greater during THC ingestion. These and other data presented are consistent with the picture of reduced sympathetic and enhanced parasympathetic activity described in animals on THC. During THC ingestion, atropine had a pronounced pressor effect, which might represent a clinically significant drug interaction.

Adult↗
PubMed1977

Effects of delta-9-tetrahydrocannabinol on drug distribution and metabolism. Antipyrine, pentobarbital, and ethanol.

Delta-9-tetrahydrocannabinol (THC) has been reported to inhibit drug metabolism in animals. Twenty-two hospitalized healthy volunteer subjects received THC, 60 to 180 mg/day in divided doses for 14 days. Body weight increased and plasma proteins decreased in all subjects, which is consistent with previously reported plasma volume expansion. Total bilirubin was significantly lower, while other liver function tests remained normal. A within-subject comparison of the pharmacokinetics of antipyrine, pentobarbital, or ethanol given before, during, and after THC was performed. Antipyrine plasma half-life increased during THC in 5 of 6 subjects--mean, 7.9 hr +/- 3.3 (SD) to 9.6 +/- 3.8. Pentobarbital half-life increased in 7 of 8 subjects--mean, 16.9 hr +/- 2.0 to 20.8 +/- 4.2. Blood ethanol disappearance rate decreased in 7 of 8 subjects from a mean of 0.26 mg/100 ml/min +/- 0.05 to 0.23 +/- 0.07. The effect of THC on disappearance rate of these drugs appeared to be due to a combination of: (1) increased distribution volume, due in part to expansion of extracellular fluid volume noted during THC ingestion, and (2) diminished metabolic clearance. THC also delayed absorption of pentobarbital and ethanol in several subjects. This is consistent with THC effects of slowing intestinal motility in animals. The effects of THC on absorption and drug elimination must be considered in evaluating interactions with other drugs.

Absorption↗
PubMed1977

Correlation of structure and active transport in the teleost nephron.

In the present study we have extended our investigations concerning the correlation between ultrastructure and active transport in the isolated flounder nephron. The composition of the fish nephron is defined in ultrastructural terms and its behavior when incubated in vitro under short term and long term culture conditions is described. Using the in vitro system originally described by Forster, a variety of inhibitors and conditions which modify cell structure and function were tested. Ultrastructure was correlated with chlorphenol red dye transport. In general, conditions altering active transport also markedly altered cellular ultrastructure. The principal alterations consisted of membrane changes involving various organelles--most importantly the plasma membrane and the mitochondria. Conditions associated with irreversible cell injury could be rapidly produced by interference either with mitochondrial ATP synthesis or with the integrity of the plasma membrane. Both of these rapidly lead to irreversible events which are preceded by reversible structural changes. Organelle changes progress in a rather well-defined sequence of reversible and irreversible stages which are defined. One difference between the two types of interactions is the presence of intramitochondrial calcification which does not occur with direct modification of the mitochondrial electron transport system. The concept of utilizing long term explant organ cultures of fish nephrons for environmental studies is introduced.

4-Chloromercuribenzenesulfonate↗
PubMed1977

Pupil size after use of marijuana and alcohol.

In an experiment using ten subjects, marijuana produced a dose-related constriction of the pupil at low photopic light levels; alcohol produced no effect on pupil size. The two drugs in combination produced no change in pupil size.

Adult↗
PubMed1977

Carcinogenesis in the pancreas. I. Long-term explant culture of human and bovine pancreatic ducts.

Bovine and human pancreatic ductal explants were maintained in long-term culture. Bovine ducts were cultured for 85 days, whereas human ducts have been cultured for up to 60 days. The explants all maintained good ultrastructural preservation for these periods and also incorporated radioactive precursors into protein, RNA, and DNA. Uncultured ducts, which were fixed for electron micrsoscopic study, demonstrated classical signs of reversible cell injury (dilated endoplasmic reticulum and swollen mitochondria), and cultured explants did not. However, the cultured tissues did show sublethal alterations such as the formation of numerous autophagic vacuoles and residual bodies and the accumulation of large lipid droplets. This study demonstrated the feasibility of maintaining pancreatic ducts in long-term explant culture, which enables them to be used in experimental studies involving chemical carcinogens and in structural and functional studies.

Animals↗
PubMed1977

Simplified complete medium for the growth of Neisseria gonorrhoeae.

A complete medium for the growth of Neisseria gonorrhoeae has been developed, using the same basic ingredients contained in commercial media but with fewer supplements. Based on a comparison of plating efficiencies, this medium (designated TTU Complete Medium) supported the growth of laboratory strains of N. gonorrhoeae equal to that obtained on commercial GC agar base medium supplemented with Iso VitaleX. It was also equivalent to the commercial medium in supporting the growth of 67 clinical isolates and 6 auxotypes of N. gonorrhoeae when tested by the streak plate method. Based on turbidity measurements and viable plate counts, the liquid equivalent of TTU Complete Medium supported maximal growth yields of N. gonorrhoeae. The toxicity of different brands of agar appeared to be a major factor in preventing the growth of N. gonorrhoeae strains on solid media. The addition of starch neutralized the toxicity of some types of agar but not of others.

Agar↗
PubMed1977

Effects of Gaseous CO2 and bicarbonate on the growth of Neisseria gonorrhoeae.

The quantitative and qualitative growth response of Neisseria gonorrhoeae strains was assessed under the following conditions: incubation in a candle jar (approximately 2.5% ambient CO2) on medium without bicarbonate, incubation in air on medium without bicarbonate, incubation in air on medium with bicarbonate, and incubation in air in a sealed jar on medium with bicarbonate. Incubation in the presence of ambient CO2 (candle jar) resulted in the highest plating efficiencies for the three laboratory strains 9, 62, and 2686. The addition of NaHCO3 to the medium enhanced the growth response in air of all three strains, particularly if incubation was carried out in a closed environment (sealed jar). The qualitative growth response of 34 clinical isolates and laboratory strains was assessed under the same conditions of incubation after the plating of an inoculum containing approximately 2 X 10(6) bacteria. The strains were divided into different classes based on their growth responses. About 40% of the strains grew as well on bicarbonate-containing medium incubated in air in sealed jars as they did on medium without bicarbonate incubated in a candle jar. Ten percent of the strains showed only slight growth on bicarbonate containing medium incubated in sealed jars and appeared to have an almost obligate requirement for ambient CO2. Twenty percent of the strains apparently had partially lost their requirement for gaseous C02 and showed slight growth in air on medium without bicarbonate and slight to moderate growth in air on medium containing NaHCO3. The remaining 30% seemed to have completely lost their requirement for gaseous C02 and/or the bicarbonate anion and grew almost as well in air on medium without bicarbonate as they did in either ambient C02 (candle jar) or on medium containing bicarbonate incubated in a sealed jar. These results suggest that N. gonorrhoeae strains may vary widely in their requirements for CO2 and/or the HCO3-anion. Incubation in the presence of ambient CO2 tends to maximize the growth response on solid medium of those strains, which require it for growth. The presence of ambient CO2 is particularly important if growth is to be obtained after the plating of small inocula. Medium conatining 0.1% NaHCO3, if incubated in a closed environment (sealed jar), apperas to be equivalent to medium without bicarbonate incubated in ambient CO2 in supporting the growth of some but not all strains of N. gonorrhoeae.

Air↗
PubMed1977

alpha-chain sequence of newt haemoglobin (Taricha granulosa).

The amino acid sequence of the alpha-chain of the major haemoglobin of a newt, T. granulosa, has been determined. The chain is 142 residues long and has an extra methionine at its N-terminus when compared with human alpha-chain. Most of the tryptic peptides were sequenced by a combination of the subtractive Edman method and by deduction from the compositions of overlapping fragments produced by various enzymic treatments. The sequence of two 'core' regions was obtained by automatic sequencing of large peptides produced by trypsin cleavage at arginine residues only after blockage of lysine residues by citraconylation; by cleavage between aspartic acid and proline residues with 70% formic acid, and by cyanogen bromide cleavage at methionine residues. The sequence of T. granulosa alpha-chain is compared with those of representative species from the other classes of vertebrates. The differences in alpha-chain between the classes of vertebrates are compared with the differences in this protein between an equal number of orders of mammals. This comparison allows us to conclude that the major functional and conformational features of alpha-chain have been conserved since the divergence of the classes of jawed vertebrates.

Amino Acid Sequence↗
PubMed1977

Brief reports influence of "mentally retarded" label on teachers' nonverbal behavior toward preschool children.

Teachers (N = 12) were assigned to either an experimental (labeled) or control (nonlabeled) child. All children were, in fact, nonhandicapped and had no diagnosis or record of mental retardation. After reading a description (labeled or nonlabeled) of their child's developmental status, each teacher read their child a story. The results indicated that teachers were more immediate (i.e., showed less social distance) to children bearing the "mentally retarded" label. Implications of this finding were discussed.

Behavior↗
PubMed1976

Hemoglobin Vancouver [alpha2beta2(73)(E17) Asp replaced by Tyr]: its structure and function.

Hemoglobin Vancouver is a new abnormal hemoglobin with an amino acid substitution of the normal aspartyl residue 73 of the beta chain by a tyrosyl residue. It was discovered in a man of Chinese descent in association with beta thalassemia. It was subsequently detected in a sister in association with normal Hb A. The oxygen affinity of the abnormal hemoglobin is decreased but its subunit interaction is normal. The Bohr effect may be slightly increased. This is the fourth abnormal hemoglobin to be found with a substitution at beta73. The others are Hb C-Harlem (alpha2beta2 6Glu replaced by Val and 73 Asp replaced by Asn), Hb Korle-Bu (alpha2beta2 73Asp replaced by Asn), and Hb Mobile (alpha2beta2 73Asp replaced by Val). Although Hb Mobile was found in the present studies to have a decreased affinity for oxygen, Hbs C-Harlem and Korle-Bu have been reported to be normal. These observations of functional differences for variants of beta73 added to earlier observations of the role of the normal beta73 residue to the aggregation of sickle deoxyhemoglobin indicate that this position of the molecule may be important in intra as well as intermolecular interactions.

Amino Acid Sequence↗
PubMed1976

Effects of practice on marijuana-induced changes in reaction time.

The effect of smoked marijuana on performance of complex reaction time (RT) tasks was studied in two groups receiving different amounts of practice. Group M-P had no undrugged practice on the task before performing during marijuana intoxication for four consecutive daily sessions. On the fifth test day they performed while non-intoxicated. Group P-M performed the task on four consecutive test days while non-intoxicated, then smoked marijuana on session 5. Significant RT slowing was found on session 1 for group M-P (performing during marijuana intoxication without prior practice). Performance of this group improved rapidly and by the end of session 2 was not different from undrugged performance. Group P-M (receiving four sessions of undrugged practice before marijuana intoxication) showed no RT slowing while intoxicated. Reaction time performance may involve two phases: an early, attention-demanding phase which is sensitive to drug effects and a later, "automatic", phase which results from practice and is more resistant to drug effects. Pulse rate, salivary flow and subjective responses were recorded before and after smoking. These physiological and subjective measures showed only slight reduction in the acute effects of the drug over the four days of repeated usage.

Adult↗
PubMed1976

Phytohemagglutinin-induced lymphocyte transformation in humans receiving delta9-tetrahydrocannabinol.

Eight otherwise healthy male chronic marijuana smokers were hospitalized for a period of 30 days. Initially they received placebo, then a sustained dose of 210 milligrams of delta9-tetrahydrocannabinol (delta9-THC) per day for 18 days, followed by placebo. Lymphocyte responses to phytohemagglutinin were examined during each of these periods. Neither the daily ingestion of marijuana extract containing 210 milligrams of delta9-THC for 18 days nor the history of chronic marijuana smoking had a depressive effect on the lymphocyte responses of these subjects to phytohemagglutinin.

Adult↗