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Biomedical subjects

R T Jones

Publications and source records attributed to R T Jones.

At least 199 records · Page 11Linked to original sources
PubMed1983

Characterization of bovine pancreatic ductal cells isolated by a perfusion-digestion technique.

Bovine pancreatic ductal cells isolated by perfusing an enzyme solution into the lumen of the main duct were obtained as sheets of cells. Morphologic features of these cells were those of pancreatic ductal epithelial cells. These cells also contained alcian blue/periodic acid-Schiff positive material and bound lectins, and they stained for keratin in the same manner as intact ductal epithelium. In culture, the plating efficiency was high (13.6%) as determined by DNA content before and after 24 h plating, perhaps due to the gentle isolation technique and the isolation of sheets of cells rather than a single cell. Cell doubling time was 34.4 h in Eagle's minimal essential medium with 10% heat inactivated fetal bovine serum and antibodies, and over 95% of the cells incorporated [3H]thymidine during a 6 h labeling period after 4 d in primary culture. Isolated cells grew best in medium CMRL 1066 with 10% heat inactivated fetal bovine serum as determined by measuring DNA content.

Animals↗
PubMed1983

Studies on Alternaria allergens. IV. Biologic activity of a purified Alternaria fraction (Alt-I).

We have previously isolated a purified Alternaria fraction (Alt-I) by means of immunochemical (RAST) assays to document allergenicity. In the present study we investigated the allergenicity of Alt-I by in vivo and in vitro biologic tests in a selected group of 16 nonimmunized Alternaria-sensitive patients, all of whom had positive skin tests to crude Alternaria extract; a control group of eight nonallergic individuals was also studied. Intradermal skin-test titration endpoints to Alt-I ranged from 60 pg/ml to 60 ng/ml in the Alternaria-sensitive patients. Alt-I induced greater than 30% in vitro leukocyte histamine in all Alternaria-sensitive patients at submicrogram concentrations. Alt-I did not produce positive skin tests or induce significant leukocyte histamine release in nonallergic individuals. In 14 of 16 Alternaria-sensitive patients bronchoprovocation testing produced greater than 20% fall in forced expiratory volume in one second at Alt-I test concentrations of 0.6 to 60 micrograms/ml. In a separate prospective study of 100 unselected individuals, concordant skin-test reactions were noted to crude Alternaria extract and Alt-I in 96 instances. These results confirm that the Alt-I fraction is a biologically active, major allergenic component of crude Alternaria extract.

Adolescent↗
PubMed1983

Failure of naloxone to reverse apomorphine effects in humans.

Twelve male volunteers given apomorphine (20 micrograms/kg/hr) for 40 min by i.v. infusion had significant changes in growth hormone, prolactin, vasopressin, pulse rate, sedation and nausea. Naloxone, (20 mg i.v.) or placebo given in a double-blind manner 10 min before the end of the apomorphine infusion as a concealed bolus did not alter the effects of apomorphine. Vasopressin rise correlated significantly with nausea intensity. We conclude that acute opiate receptor blockade does not reverse most apomorphine effects.

Adolescent↗
PubMed1983

Smoking cessation in patients with cardiopulmonary disease: an initial study.

Thirty-five smokers, all with current, long-standing, cardiovascular or pulmonary disease, were randomly assigned to either health motivation treatment, or to aversive smoking. The former included self-management skills, a film model, verbal commitment, and discussion of the costs and benefits of smoking and abstinence. The latter included normally paced (every 30 sec.) aversive smoking, relaxation training, role playing high risk situations, and discussion of maladaptive thought patterns. Strong differences between the conditions in abstinence rate and reduction from baseline did not emerge; however, the data generally favored the health motivation condition both in attrition rates and in outcome immediately posttreatment and at six month follow-up. Negative mood states were found to be related to minimal reduction in smoking; and consistent mood dysphoria at pre and posttreatment predicted relapse at three month follow-up.

Affect↗
PubMed1983

How a cigarette is smoked determines blood nicotine levels.

Indirect evidence suggests that smoking low-tar and nicotine cigarettes does not necessarily reduce exposure to these substances. Puff volume, duration and number, interpuff interval, and volume and duration of inhalation were measured while 11 subjects smoked two or four tobacco cigarettes. Nicotine blood levels and breath CO were measured before and after smoking. The machine-determined nicotine yields of the cigarettes correlated (r = 0.52) with the increase in nicotine blood levels after smoking but, when individual differences in smoking behavior were taken into account along with the nicotine yield, there was a stronger correlation with nicotine blood levels (r = 0.84 to 0.93).

Breath Tests↗
PubMed1983

Cotinine disposition and effects.

Cotinine is the major metabolite of nicotine in man. We studied cotinine disposition kinetics in 28 healthy habitual cigarette smokers. Eight subjects received cotinine fumarate, 4 micrograms base/kg/min IV for 60 min. Mean (+/- SD) metabolic clearance was 60 +/- 12 ml/min and mean renal clearance was 12 +/- 5 ml/min, averaging 17% of total clearance. Steady-state volume of distribution was slightly greater than body weight (mean 88 +/- 17 l). Terminal t 1/2 averaged 15.8 +/- 4.0 hr in these eight subjects and 19.7 +/- 6.5 hr in another 12 subjects who abstained from smoking for 3 days. The effect of urinary acidification and alkalinization on renal clearance of cotinine during cigarette smoking was studied in another group of eight subjects. Compared with baseline (mean urinary pH 5.8, renal clearance 12.3 +/- 5.9 ml/min), renal clearance was increased about 50% by urinary acidification (pH 4.4, clearance 18.6 +/- 10 ml/min), but it was not affected by alkalinization (pH 6.7, clearance 14.0 +/- 10.4 ml/min). Infusion of cotinine to blood concentrations seen in moderately heavy smokers had no effect on heart rate, blood pressure, or skin temperature, measures that are sensitive to effects of nicotine. No spontaneous subjective effects were reported. We conclude that, at levels to which cigarette smokers are generally exposed, cotinine exerts no cardiovascular activity and weak, if any, psychologic activity.

Adult↗
PubMed1983

Cannabis and health.

The effects of cannabis on health are not easy to summarize. What little is known for certain and what can be inferred from an enormous but incomplete and imperfect literature is that cannabis under certain conditions is harmful to health. Given the breadth and complexity of the issues, this very selective review only considers health-related consequences where there was consensus by two independent scientific review groups.

Abnormalities, Drug-Induced↗
PubMed1983

Hb S Mobile: a new genetic combination.

The genetic combination of Hb Mobile (beta 73 Asp replaced by Val) and Hb S (beta 6 Glu replaced by Val) was found in a healthy black man whose hemolysate resembles that of Hb S electrophoretically. His mother and sister have Hb AS; the father and brother have Hb A Mobile. No clinical nor hematologic abnormalities were detected in any member of the family. A slightly decreased oxygen affinity associated with Hb Mobile appears to have no clinical significance. Simple methods of differentiating Hb Mobile S from the electrophoretically similar but clinically severe Hb SD Los Angeles are described.

Adolescent↗
PubMed1983

Oxygen equilibrium studies of Hb Willamette alpha 2 beta (2)51(D2)Pro leads to Arg.

The homotropic and heterotropic effects of isolated Hb Willamette were studied using an automatic recording oxygen equilibrium analyzer. The results indicate that Hb Willamette displays normal intrinsic oxygen binding in the stripped condition. An apparent decrease of the Bohr effect is explained by the decrease of allosteric effects in this abnormal hemoglobin. Furthermore, the lack of clinical manifestations in the original patient is consistent with the red cell oxygen equilibrium studies.

Chlorides↗
PubMed1983

The pathophysiology of septic shock: responses to different doses of live Escherichia coli injection in rats.

Responses to different doses of Escherichia coli (E coli; 0-18) injection were studied from the pathological standpoint. Various amounts of live E coli were intravenously injected through the tail vein (group A: 2.7-3.3 X 10(9); B: 1.7-2.0 X 10(9); C: 1.2-1.5 X 10(9); D: 0.3-0.5 X 10(9) organisms/100 g of body weight). All rats from group A died within 6 h; 14 out of 15 rats from group D survived. Hypothermia was commonly seen in the lethal groups (groups A, B, and C) prior to death, and hyperthermia was observed only in groups C and D. Leukopenia was seen in all groups and remained in the lethal groups, whereas in group D, leukocytosis following leukopenia was observed at 12 and 24 h. Light microscopic studies were performed in the lethal groups, showing the following differences among the three lethal groups; a dose-related depletion of white pulp of the spleen, cortical hemorrhage of the adrenal glands (only in groups A and B), foci of bacterial colonies in the heart and small intestine with aggregated leucocytes (only in group C); focal liver necrosis was found in group C, but not in group A. Tubular necrosis and cast formation were also predominant in the kidneys of group C animals. The above findings indicate that the milder, lethal group shows more severe morphological changes in all organs except the spleen and adrenal glands, and suggest that sudden death from bacteremia may involve a depleted host defense.

Adrenal Glands↗
PubMed1983

Evidence for dopamine-containing renal nerves.

The existence of the specific renal DA1 postsynaptic receptor for dopamine (DA) has prompted the search for a counterpart dopaminergic innervation. In the canine kidney there is an increased proportion of DA as a percentage of norepinephrine (NE), and both NE and DA are lost after chronic denervation. In the rat and dog, renal stimulation increases the net secretion of both NE and DA; renal denervation eliminates NE but only partially reduces DA secretion. Histological techniques have identified DA-containing neuronal elements in the kidney. Thus there is growing evidence for a prejunctional dopaminergic counterpart to the DA1 receptor.

Animals↗
PubMed1983

Methods for transport and long-term maintenance of spiny dogfish sharks.

Spiny dogfish shark (Squalus acanthias) embryos were transported from Maine to the Maryland laboratory where they were maintained for 20 months. During this maintenance period, these sharks progressed from a yolk-sac stage to feeding stage. Animals were maintained at 10 degrees C in artificial seawater containing penicillin and streptomycin and were fed frozen brine shrimp and krill. The ease with which these animals could be maintained in the laboratory for an extended period of time greatly enhanced their usefulness as an experimental animal in a variety of studies.

Animal Husbandry↗
PubMed1983

Effect of hypothermia on survival time and ECG in rats with acute blood loss.

The effects of hypothermia on survival time and ECGs were investigated in hemorrhagic-shocked rats. Acute blood loss corresponding to LD84 was achieved within 1 min through cannulation of the carotid artery. Immediately following the hemorrhagic episode, extracorporeal cooling was performed by placing the animals, with ice packs attached to their lateral sides, in a cold water bath. Rewarming was achieved by removing the ice packs and resetting the temperature of the water bath to 37 degrees C. With this system, the survival time of the hemorrhagic rats was lengthened from 40 to 60 min without rewarming and to 123 min with rewarming. ECGs showed sinus bradycardia, prolonged PR and QRS intervals, AV block, and finally ventricular fibrillation in both the control and hemorrhagic groups during extracorporeal cooling. During rewarming, the above ECG changes returned to normal in the control group as did body temperature. In contrast, animals in the hemorrhagic group did not survive. Body temperature in this group began to rise toward normal, and above ECG changes showed slight but not complete improvement. It is concluded that extracorporeal cooling can lengthen the survival time of hemorrhagic-shocked rats and that recovery of the disturbed conduction system is a prerequisite for survival from severe hypothermia.

Acute Disease↗
PubMed1982

Presynaptic plasma membranes and synaptic vesicles of cholinergic nerve endings demonstrated by means of specific antisera.

Antisera were raised to cholinergic presynaptic plasma membranes and synaptic vesicles isolated from the electric organ of Torpedo marmorata and tested by immunochemical and immunohistochemical methods. The antisera responded to many antigens not specific to nerve endings, but it was possible to eliminate these antibodies by means of simple absorption procedures with fractions containing the unwanted antigens. After absorption, staining of thin sections of electric organ by immunofluorescence was limited to the region of nerve endings in the tissue. The remaining antibodies responded in the case of the plasma membrane antisera predominantly to a 33,000 molecular-weight polypeptide and a chloroform/methanol-soluble antigen. In cross reactivity studies it was found that this antiserum not only stains cholinergic nerve endings in Torpedo but also those in mammalian tissue. The antigen responsible for the cross reactivity is restricted to the chloroform/methanol-soluble material. The vesicle antiserum labels cholinergic nerve endings in mammalian tissue as well; the relevant antigen in this case is different from the one described above and is likely to be a glycosaminoglycan. The antisera provide valuable markers for cholinergic nerve terminals. In addition, the vesicle antiserum may now be used to study axonal transport and the life cycle of this organelle in the cholinergic neurone.

Animals↗
PubMed1982

Immunohistochemical localization of a synaptic-vesicle antigen in a cholinergic neuron under conditions of stimulation and rest.

An antiserum against a specific component (a glycosamino glycan) of the cholinergic synaptic-vesicle of Torpedo marmorata has been used to investigate the localization of the component in the cell body, its movement within the electromotor axon and its fate within the nerve terminal upon electrical stimulation. After immunofluorescent staining, spots are observed throughout the cytoplasm of the lobe perikarya, although they are concentrated in the region of the axon hillock. Ligation of the electromotor nerves leading from the lobe to electric organ produces a proximal build-up of material which stains readily with the antivesicle antiserum, indicating that the vesicle antigen is transported from the cell body to the nerve terminal. A marked increase in indirect immunofluorescent staining of the electric organ is observed in the nerve ending upon electrical stimulation. We interpret this result as fusion of the vesicles with the presynaptic plasma membrane and exteriorization of the vesicle antigen to the extracellular space, thereby facilitating its staining. After recovery of the system the fluorescence declines, a result that is consistent with the reinternalization of the vesicle antigen into the core of reformed vesicles. The results support a mechanism whereby vesicles recycle within the nerve terminal and transmitter is released by exocytosis.

Animals↗