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Biomedical subjects

D A Johnson

Publications and source records attributed to D A Johnson.

At least 343 records · Page 19Linked to original sources
PubMed1981

Oral versus depot medication in schizophrenia.

More recent experience and research may well have modified the original claims and expectations of the advantages of depot injections over oral medication, and these observations are almost certainly valid. However, for long-term maintenance therapy there remain certain clear advantages which have been outlined, and in the circumstances of normal clinical practice, with all its variations, these advantages would seem to be overwhelming. In the absence of any specific disadvantages, it is fair to conclude that even if the two methods of administration lead to no pharmacological differences, clinically, depot injections remain the better treatment in long-term maintenance therapy. It represents an organised management of the patient, his illness and his treatment far beyond the simple administration of a drug.

Administration, Oral↗
PubMed1981

Depressions in schizophrenia: some observations on prevalence, etiology, and treatment.

The results suggest that not only is depression a common symptom or syndrome in all stages of schizophrenia, but it is common even in the absence of treatment. However, there are a number of reasons for thinking that a proportion of patients on drugs may well suffer from drug related depressions, possibly 7.5-12.5 per cent. A difference in the effect upon mood, in the acute schizophrenic state, between flupenthixol and fluphenazine, has already been suggested (Johnson & Malik (1975)). Current research (Johnson (1976, 1979)) suggests that regular neuroleptic maintenance therapy is necessary for many years, certainly for more than four years following the most recent relapse. It is therefore of particular importance to concern ourselves with all potential side-effects such as extrapyramidal symptoms, weight gain (Johnson & Breen (1979)) an tardive dyskinesia (Gibson (1978)), and to keep the patients on personalised dose regimes which can frequently be reduced with time, particularly over the first two years of treatment (Johnson (1975, 1977)). WE must equally be on our guard against unnecessary polypharmacy which ultimately increases the risks for an already greatly disadvantaged patient.

Antidepressive Agents↗
PubMed1981

Post-natal reduction of neural unit size in the rabbit ciliary ganglion.

We have studied the innervation of adult and neonatal ciliary ganglia in the rabbit to determine the average number of ganglion cells innervated by each preganglionic neurone at different stages of development. 1. The adult ciliary ganglion comprises about 380 ganglion cells which are innervated by about forty preganglionic neurones. 2. Ciliary ganglion cells in adult rabbits are on average innervated by 2.2 different axons; in contrast, neonatal ganglion cells are on average innervated by 4.6 different axons. The transition to the adult pattern of innervation occurs gradually during the first few post-natal weeks. 3. The numbers of ganglion cells and preganglionic neurones do not change appreciably after birth. Accordingly, the loss of some innervation to individual neurones during post-natal development indicates that each preganglionic axon innervates progressively fewer ciliary ganglion cells. 4. The number of synaptic boutons found in ganglia at birth, however, is less than the number of synaptic boutons found in adult ganglia. 5. We conclude that synaptic connexions in this ganglion age gradually rearranged in early post-natal life such that each preganglionic neurone focuses an increasing number of synaptic contacts on a progressively smaller subset of the ganglion cell population.

Aging↗
PubMed1981

Drug-induced psychiatric disorders.

This article is a review of the principal drug-induced psychiatric symptoms that are likely to be encountered in daily clinical practice as a result of drug abuse, overdoses or side effects of drugs prescribed for treatment. Many categories of medication have the potential to produce psychiatric symptoms, but antitubercular drugs, hypotensive agents and steroids have the highest incidence in clinical practice. Additionally, the problems of alcohol are all too frequently overlooked. The variety and frequency of secondary psychiatric symptoms which may be drug-related emphasise the importance of a careful consideration of all drugs taken by a patient with psychiatric complaints, to determine causal association with symptoms.

Alcoholic Intoxication↗
PubMed1981

Immune responsiveness of HRS/J mice to syngeneic lymphoma cells.

HRS/J, hr/hr and hr/+ mice were evaluated for their ability to resist challenge with a syngeneic tumor, HTU, and for their ability to mount a protective immune response when immunized in vivo with inactivated HTU cells previous to challenge with viable tumors. The heterozygous (hr/+) mice responded more strongly than the homozygous (hr/hr) mice. This response was characterized by the presence of an enhanced ability of spleen cells from immunized mice to form blasts in vitro when incubated with purified murine leukemia viruses (MuLV). We conclude that the in vivo response of HRS/J mice against this tumor is directed, in part, against MuLV antigens expressed on the tumor cells and that the relatively weak response of hr/hr spleen cells to these antigens may be mechanistically linked to their tumor susceptibility.

Aging↗
PubMed1980

(+/-)-trans-2-(Aminomethyl)cyclobutanecarboxylic acid hydrochloride: a rigid analogue of gamma-aminobutyric acid.

The (+/-) title compound was prepared to evaluate prior observations that certain gamma-aminobutyric acid (gamma Abu) congeners in the transoid disposition demonstrate gamma Abu receptor binding activity. It was prepared by a multistep sequence from (+/-)-methyl trans-2-(hydroxymethyl)cyclobutanecarboxylate. In a sodium-independent binding assay, the specific binding of (+/-)-1 to synaptic membranes from rat brain tissue was 1/14 500 that of gamma Abu.

Animals↗
PubMed1980

The release of acetylcholine from post-ganglionic cell bodies in response to depolarization.

1. Acetylcholine (Ach) release from parasympathetic ganglia cell somata was investigated in denervated avian ciliary ganglia. Three days after the input to the ganglion (the oculomotor nerve) was sectioned, all presynaptic nerve terminals had degenerated. 2. Denervated ganglia were shown to contain endogenous ACh and to be capable of synthesizing [3H]ACh from [3H]choline added to the incubation medium. 3. In response to depolarization induced by incubation in 50 mM-[K+]o, denervated ganglia released [3H]ACh into bath effluents in amounts approximately 15% of the non-denervated contralateral control. This release was shown to be Ca2+ dependent in both intact and denervated ganglia. 4. Antidromic electrical stimulation of ciliary nerves also elicited [3H]ACh release. Nicotine (1 microgram/microliter.) depolarized denervated ciliary ganglion cells and evoked release of the transmitter and this release was antagonized by curare. 5. It is concluded that the ganglionic cell bodies sysnthesized ACh and released the transmitter in response to K+ depolarization, antidromic stimulation and cholinergic agonists, despite the lack of morphological specializations usually associated with stimulus-induced release of neurotransmitter. The evidence suggests the existence of a mechanism of transmitter release which is Ca2+ dependent, probably from a cytoplasmic pool and therefore distinct from the usual vesicular release at the nerve terminal.

Acetylcholine↗
PubMed1980

Leukemogenesis, immune responsiveness, and murine leukemia virus expression in congenic AKR/J mice differing at H-2.

In this study we examined the leukemia incidence, ectropic and xenotropic murine leukemia virus expression, and immune responsiveness of congenic AKR/J mice differing at the H locus. Congenic AKR.L-H-2b/1 mice, bearing the H-2b haplotype derived from C57L/J, were found to have a significant delay in time of death due to leukemia relative to that of AKR/J (H-2k) mice. The expression of ecotropic murine leukemia virus was found to be identical in both strains. The expression of xenotropic murine leukemia virus did vary, however, with the AKR.L-H-2b/1 mice showing a significantly reduced level of virus expression relative to AKR/J mice. In addition to these observations, we found that the AKR.L-H-2b/1 mice have an enhanced blastogenic responsiveness to phytohemagglutinin and to specific antigen to which they had previously been sensitized. Concomitant enhanced antibody response was not found. We suggest that the stronger cellular response, relative to AKR/J, may contribute to the delay in leukemia onset and to reduced xenotropic virus expression observed with the congenic mice.

Animals↗
PubMed1980

Tn2301, a transposon construct carrying the entire transfer region of the F plasmid.

The largest R . BamHI fragment of the plasmid F, which carries the entire F conjugation system, has been cloned into the single R . BamHI site of the ampicillin (Ap) resistance transposon TN1. pDS1106 (ColE1 mob::Tn1) was the vector plasmid, and the resultant conjugative plasmid, pED830, was characterized both genetically and by restriction enzyme analysis. The transposon construct, denoted Tn2301, was transposable at frequencies similar to Tn1 to small nonconjugative plasmids or to the Escherichia coli host chromosome. In the former case, Apr conjugative plasmids were obtained, whereas in the latter case, Hfr strains resulted. Representative Hfr strains were characterized by quantitative and interrupted mating experiments. Extension of this technique for Hfvr formation should aid chromosome mapping both in E. coli and in other bacterial genera.

Ampicillin↗
PubMed1980

Ozone inactivation of human alpha 1-proteinase inhibitor.

Ozone decreased the trypsin, chymotrypsin, and elastase inhibitory activities of human alpha 1-proteinase inhibitor (alpha 1-PI) both in plasma and in solutions of the pure inhibitor. The total loss of porcine elastase inhibitory activity required 18 mol of ozone/mol of pure alpha 1-PI and approximately 850 mol of ozone/mol of alpha 1-PI in plasma. A corresponding loss of the ability to inhibit human leukocyte elastase was observed. Inactivated alpha 1-PI contains four residues of methionine sulfoxide, in addition to oxidized tyrosine and tryptophan. Electrophoretic analysis demonstrated that the ozone-inactivated alpha 1-PI did not form normal complexes witrh serine proteinases. These findings suggest that the inhalation of ozone could inactivate alpha 1-PI on the airspace side of the lung to create a localized alpha 1-PI deficiency, which might contribute to the development of emphysema.

Amino Acids↗
PubMed1980

Effectiveness of a mailed reminder on the immunization levels of infants at high risk of failure to complete immunizations.

The Ohio Department of Health initiated a program of mailing an immunization reminder to the mothers of six-month-old children predicted to be at high risk of failure to receive vaccinations based on birth certificate information. The evaluation results indicated a 50% gain in immunizations amongst children whose parents received the letter when compared with those not receiving the letter.

Evaluation Studies as Topic↗