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Biomedical subjects

R Jones

Publications and source records attributed to R Jones.

At least 1,009 records · Page 56Linked to original sources
PubMed1976

Effects of marijuana extract and tetrahydrocannabinol on electroencephalographic sleep patterns.

Marijuana extract, given in daily doses containing 70 to 210 mg delta-9-tetrahydrocannabinol (THC), induced effects on sleep that were virtually identical to those produced by the same doses of relatively pure (96%) THC. Both drugs reduced eye movements density with some tolerance developing to this effect. Stage 4 tendend to increase with drug administration. Abrupt withdrawal led to extremely high densities of eye movement, increased rapid eye movement (REM) durations, and a sharp but transient fall in stage 4 to baseline levels. These effects may be useful in the elucidation of the pharmacology of sleep. The effects on sleep of THC administration (but not withdrawal) closely resemble those induced by lithium. For this reason, we suggest further studies of THC in affective disorders. Evidence available thus far suggests that THC produces dysphoric symptoms in unipolar but not in bipolar depressed patients; these differences in response may prove of diagnostic value. An adequate therapeutic trial of THC in bipolar depressed patients has not yet been carried out.

Administration, Oral↗
PubMed1976

Identification of glycoproteins in goblet cells of epidermis and gill of plaice (Pleuronectes platessa L.), flounder (Platichthys flesus (L.)) and rainbow trout (Salmo gairdneri Richardson).

A quantitative analysis has been made of the glycoproteins present in the goblet cells of the epidermis, gill filaments and gill lamellae of three species of teleost fish. The glycoproteins have been identified by a combination of techniques, including the use of the enzyme sialidase followed by Alcian Blue staining, at PH 2.6 or 1.0, in combination with periodic acid-Schiff. The selected fish were representative of species living in marine, freshwater and estuarine environments. The range of glycoproteins identified in these fish was similar to that found in mammalian tissue in that both neutral and acid glycoproteins were present, the latter included both sialomucins sensitive and resistant to sialidase, and sulphomucin. A single goblet cell contained either neutral or acid glycoproteins alone or in combination. Only the epidermis of the plaice and rainbow trout contained uniform cell populations producing acid glycoproteins, the former sulphomucin and the latter mainly sialomucin. At each site in the flounder and in the gill epithelia of the plaice and rainbow trout, the goblet cell population was mixed, with cells producing each type of glycoprotein. The number of goblet cells producing each type of glycoprotein varied at each tissue site.

Alcian Blue↗
PubMed1976

Echocardiographic evaluation of tricuspid valve endocarditis: an M mode and two dimensional study.

Standard M mode echocardiography and a new real time two dimensional echocardiographic imaging system were utilized to follow the progressive anatomic destruction of the tricuspid valve in a patient with bacterial endocarditis. The initial two dimensional echocardiographic study revealed large vegetative masses attached to severely prolapsing tricuspid leaflets. Serial studies demonstrated eventual disruption of the chordal attachments of the anterior tricuspid leaflet resulting in frank leaflet flail. This technique was seen to complement both M mode echocardiography and cardiac angiography by providing spatial information concerning serial changes in the disordered tricuspid valve. Such findings call attention to the relative roles of various diagnostic measures, including M mode and two dimensional echocardiography, in assessing the specific anatomic and functional performance of a diseased tricuspid valve.

Adult↗
PubMed1976

Surgical aspects of airway management in infants and children.

The surgical management of the upper airway in infants and children varies in many important details from the principles of airway management usually applied to adults. Recent technical adaptations and innovations have improved our ability to deal with upper airway obstruction effectively. Advances in respiratory support for sick infants have saved thousands of lives and at the same time produced a new spectrum of airway problems which must be dealt with effectively. The surgeon who takes on such problems should be specially trained and dedicated to the unique requirements of infants and children.

Adolescent↗
PubMed1976

Conservatism as a determinant of sexual experiences.

An examination of the relationship of conservatism to reports of sexual experiences and reasons for nonparticipation was conducted using 64 male and 50 female introductory psychology students. Conservatism was found to be inversely related to the frequency and variety of sexual behaviors. High conservative subjects gave the reason that it was morally wrong more often than any other reason for not engaging in coital activities and more intimate forms of petting. Results were in accord with previous research and were interpreted as supporting the notion that the fear of loss of control of one's impulses and hence the basis for conservative attitudes are determinants of sexual experiences.

Attitude↗
PubMed1976

Automated electro-oculography.

Automation of the EOG has the chief advantage that the clinician is relieved of the normal complexities and the time demands of this test. He needs only to be concerned with the interpretation of the final outcome for diagnosis. The expense of this method, relative to the standard techniques, must be assessed according to the circumstances of the clinical setting. At present it certainly cannot be justified in the private clinical practice due to its low level of utilization. However, in a college or large clinic, where a general purpose minicomputer is available, automated control of the EOG test may be the most economical in terms of the additional expenditures required for equipment and manpower.

Diagnosis, Computer-Assisted↗
PubMed1975

Spin-labelled phosphofructokinase. A simple and direct approach to the study of allosteric equilibria under near-physiological conditions.

Rabbit muscle phosphofructokinase, spin-labelled at its most reactive thiol group, has an electron spin resonance spectrum which is very sensitive to the binding of substrates and allosteric effectors. The spectral changes have been interpreted in terms of a concerted allosteric transition between two conformational states with non-exclusive binding of effectors. On this basis MgATP, fructose 6-phosphate plus ATP, and NH+4ions behave as potent positive effectors, inorganic phosphate, sulphate, AMP, fructose 6-phosphate and fructose 1,6-bisphosphate are less potent activators, and free ATP and H+ions are negative effectors, in agreement with the kinetic behaviour, but citrate behaves anomalously. In addition, the allosteric equilibrium can be displaced towards the inhibited state by selectively modifying two further thiol groups. Strong positive cooperativity occurs under suitable conditions with ATP, metal-ATP and fructose 6-phosphate. Biphasic changes of conformation, attributed to binding at the catalytic and inhibitory sites, have been observed in titrations with ATP. The differentiation of the two ATP binding sites arises in the presence of fructose 6-phosphate because of a distinct concerted effect on conformation between the two substrates at the active site. A similar effect occurs between ATP and citrate. Other heterotropic effects are more consistent with simple models; phosphates favour the binding, and reduce the cooperativity, of fructose 6-phosphate and metal-ATP, whereas excess ATP and H+ ions antagonise the binding and increase the cooperativity of fructose 6-phosphate. The observations are related to existing kinetic and binding studies where possible. Anomalous features of the behaviour suggest that the model should be regarded only as a first approximation.

Adenosine Triphosphate↗
PubMed1975

Antibody--hapten interactions in solution.

This paper reports the initial progress in a research programme to identify and obtain the relative orientations, in solution, of the amino acid residues that constitute the combining site of the myeloma protein MOPC 315. This protein has a molecular mass of 150,000, but enzymic digestion yields the Fv fragment of molecular mass 25,000 which still has the combining site intact, as judged by the affinity for dinitrophenyl haptens. Analysis of the e.s.r. spectra of a series of dinitrophenyl spin labelled haptens has allowed the dimensions, rigidity and polarity profile of the combining site to be determined. The combining site is a cleft of overall dimensions 1.1 nm x 0.9 nm x 0.6 nm which has considerable structural rigidity. One of these spin labels has also been used to perturb the n.m.r. spectrum of the Fv and using difference spectroscopy the 270 MHz proton n.m.r. spectrum of the amino acid residues in and around the combining site has been obtained. This spectrum contains only the equivalent of about 30 aromatic and 21 aliphatic protons. Comparison of this difference spectrum with that obtained using a diamagnetic analogue suggests that any conformational changes on hapten binding are mainly localized to the combining site. By the use of (n.m.r.) difference spectroscopy the protons of the three histidine residues in the Fv are observed to titrate with pH and have pKa values of about 8.1, 6.9 and 6.1. The histidine resonances with pKa values 6.9 and 6.1 alter slightly in the presence of haptens and also appear in the spin label difference spectrum, and must therefore be in or near to the combining site. These are assigned to His 102H and His 97L. The existence of lanthanide binding sites on the Fv, necessary for the mapping studies, has been demonstrated by measurements of Gd III water relaxation rates in Fv solutions and also by the changes in the Fv tryptophan fluorescence on addition of Gd III. At pH 5.5 there is one tight binding site for the lanthanides (KD approximately 80 muM) but in the presence of hapten this is weakened 10-20 fold with a reciprocal effect on the hapten binding. Measurements of the Gd III quenching of the e.s.r. spectrum of a spin labelled hapten bound to Fv indicate that the lanthanide site is ca. 1.5 nm from the nitroxide moiety.

Amino Acids↗
PubMed1975

An electrophysiological examination of the changes in skeletal muscle fibres in response to degenerating nerve tissue.

Endplate free areas of the emebrane of soleus and extensor digitorum longus muscles of the rat, covered fpor 3 days by a piece of nerve from the brachial region, become locally sensitive to ACh applied iontophoretically. Mean ACh sensitivity is increased at this site in the extensor muscle from 0 in areas not covered by the nerve to 6.27 mV/nanocoulombs (nC) +/- 1.28 (S.E.), in the area under the nerve and in soleus from 0.12 mV/nC +/- 0.05 (S.E.) to 24.2 mV/nC +/- 4.6 (S.E.). Increase in sensitivity is accompained by a decrease of resting membrane potential. Mean values are (unaffected areas) 75.0 mV +/- 0.55 (S.E.) to (affected area) 65.0 mV +/- 0.56 (S.E.) in soleus and (unaffected areas) 76.3 mV +/- 0.61 (S.E.) to (affected area) 67.0 mV +/- 0.55 (S.E.) in extensor digitorum longus. These changes are local in individual fibres. Changes in ACh sensitivity and resting membrane potential in the area covered by the nerve are temporary, and after 6 days no sign of increase in sensitivity and drop in membrane potential were observed. The piece of nerve loses its potential to induce AHh sensitivity when it is heated to 98 degrees C for 5 min or soaked for 2 h in distilled water.

Acetylcholine↗
PubMed1975

Inhibition of cell division and the development of denervation hypersensitivity in skeletal muscle.

1. It was found that in 3 day denervated soleus and EDL muscles nuclear division takes place. This can be stopped by administration of either 5-fluoro-uracil or vincristine. 2. The increased sensitivity to acetylcholine following denervation developed at a time when rapid cell division takes place. Both 5-fluoro-uracil and vincristine prevent the development of denervation hypersensitivity both in soleus and EDL muscles. 3. Muscle injury causes some cell division locally, but some phagocytic cells that infiltrate the damaged muscle appear to be blood-borne as their appearance within the muscle is not entirely prevented by either 5-fluoro-uracil or vincristine. Correspondingly the development of increased sensitivity that follows muscle injury is only partly prevented by administration of cytotoxic drugs. 4. It is suggested that the presence of dividing cells is causally related to the development of denervation hypersensitivity.

Acetylcholine↗
PubMed1975

Effects of high dosage delta-9-tetrahydrocannabinol on sleep patterns in man.

Electroencephalographic readings and eye movement were recorded in experienced marijuana users under placebo and tetrahydrocannabinol (THC). Four subjects were studied for 3 baseline nights, 3 nights under initial dosage of 70 mg/day, the last 3 nights of a 2-wk period of 210 mg/day, and the first 3 nights of withdrawal. Three other subjects were studied only during the latter 2 conditions. Administration of THC significantly reduced eye movement activity during sleep with rapid eye movements (REM) and, to a lesser extent, the duration of REM itself. Withdrawal led to increases above baseline in both measures but the "rebound" effect was greater for eye movement. Stage 4 sleep tended to increase on drug, but this effect was not statistically significant. On withdrawal, stage 4 sleep decreased significantly; this change was marked only on the first withdrawal night. The functional or biological significance of these changes is unclear. Nevertheless, these are the most marked effects of THC on brain electrical activity demonstrated thus far. Since its pattern of effects on sleep appears unique to THC, this drug may prove to be a valuable tool in the elucidation of the pharmacology of sleep. Possible relations between effects on sleep pattern and on behavior are discussed.

Adult↗
PubMed1975

Histochemical identification of glycoproteins in pig bronchial epithelium: (a) normal and (b) hypertrophied from enzootic pneumonia.

The glycoproteins in the normal pig bronchial gland are identified by the combined Alcian Blue (AB)-periodic acid Schiff (PAS) technique, with the use of sialidase digestion and AB staining either at pH 2-6 or at pH 1-0. In enzootic pneumonia (produced experimentally by infection with Mycoplasma hyorhinis) the bronchial gland hypertrophies, mucous and serous cells both increase, in number and size; hence the total glycoprotein content of the gland increases. The distribution of glycoproteins in the hypertrophied gland differs from that in the normal. Quantitative analysis of the mucous cells shows that in the hypertrophied gland the acid glycoprotein is increased relative to the neutral. There is also a relative change in the amounts of sialidase-sensitive sialomucin and sulphomucin; both are significantly increased at the expense of the sialidase-resistant sialomucin. Qualitative analysis of the serous cells shows that in the normal gland most of the glycoprotein is neutral and that the small amount of acid glycoprotein is sialidase-resistant sialomucin. In the hypertrophied gland there is relatively more acid glycoprotein which is either sialidase-resistant sialomucin or sulphomucin; in addition, in pigs with enzootic pneumonia there is an increase in the height of the bronchial epithelium and a depletion in both goblet cell number and glycoprotein content, which latter has more neutral glycoprotein and less acid glycoprotein.

Animals↗