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Biomedical subjects

D M Armstrong

Publications and source records attributed to D M Armstrong.

At least 145 records · Page 8Linked to original sources
PubMed1977

Renal function after warm ischaemia. II. Marked protective effect of intravenous inosine given prior to 60, 90 and 120 min of warm ischaemia.

Rats were given 10 or 20 mg of inosine dissolved in 1 ml of 0.9% saline, or a control solution of 1 ml of 0.9% saline, intravenously 10 or 20 min before induction of left renal warm ischemia for 60 min. Further groups of rats were treated with 20 mg inosine or with saline alone 20 min before longer periods of warm ischeamia of 90 and 120 min duration. All animals had immediate contralateral nephrectomy. In all inosine-treated groups the mean plasma creatinine was lower than in their respective control groups and these differences were statistically highly significant.

Animals↗
PubMed1976

Enhanced preservation of the ischaemic kidney with inosine.

The function of rat kidneys subjected to 60 minutes of warm ischaemia at body-temperature was notably protected by the prior administration of the purine nucleoside inosine as a 40 mg/ml solution maintained at 37 degrees C. With direct intrarenal arterial perfusion of the kidney at the onset of ischaemia or with intraperitoneal (i.p.) injection 40 minutes before ischaemia, the plasma-creatinine at 24 hours was significantly lower (P less than 0-001) than that of untreated 60-minute-ischaemia controls and not significantly different from that of non-ischaemic unilateral-nephrectomy controls. Intravenous inosine 20 minutes beforehand also afforded significant (P less than 0-01) protection. 7-day survival was 100% in 30 inosine-pretreated rats and 65% in 45 rats with all other types of pre-treatment (P less than 0-001). Although i.p. adenosine was better (P less than 0-05) than no treatment, i.p. inosine was better (P less than 0-02) than i.p. adenosine. Allopurinol, phenoxybenzamine, A.T.P., or cyclic A.M.P. caused no improvement over controls. Kidneys perfused with inosine maintained higher purine-nucleotide levels during ischaemia and rapidly resynthesised A.T.P. when blood-flow was restored in vivo.

Adenosine↗
PubMed1976

Treatment of advanced malignancy with CCNU (NSC 79037): a phase II cooperative study with long-term follow up.

CCNU (1-[2-chloroethyl]-3-cyclohexyl-1-nitrosourea, NSC-79037) was used to treat advanced malignancies in 329 evaluable patients. The treatment dosage was 130 mg/m2 for patients with adequate bone marrow reserve and 100 mg/m2 for those with compromised bone marrow. Oral treatment was repeated at 6-week intervals unless hematologic toxicity intervened. There were four complete responses: two in ovarian cancer, one with small cell carcinoma of the lung, and one with melanoma. Tumor response greater than 50% reduction in tumor size occurred in 39 patients (11.9%) while stable disease (no change or decrease or increase of less than 50% in tumor size) was noted in 152 patients (46.2%). Tumor progression occurred in 130 cases. Melanomas and ovarian and lung cancers had the highest response rates. Bone marrow depression was the major side effect of treatment; there was a significant positive correlation between the severity of leukopenia and thrombocytopenia and tumor response to treatment.

Humans↗
PubMed1975

Systemic chemotherapy of advanced head and neck malignancies.

Several Phase II chemotherapy protocols were evaluated in patients with advanced malignancies; 158 were evaluable head and neck cases. The protocols were as follows: five-drug combination (COMFP), four-drug (COMF), (CCNU, Adriamycin, DTIC, and cytosine arabinoside. Insufficient numbers and data were received to adequately evaluate Yoshi 864, 5 Azacytidine, porfiromycin, BCNU, and Azaserine. Significant responses to therapy were noted in the four and five-drug combinations in which 30-44% of the patients had 50% or greater regression, with an average duration of 2.2 months. Adriamycin and CCNU demonstrated lesser antitumor effects, while DTIC and cytosine arabinoside did not demonstrate significant antitumor activity in the head and neck areas. Usual toxicity consisted largely of nausea and vomiting, leukopenia, and thrombocytopenia. Alopecia was not pronouced in Adriamycin-treated patients. It appears that combination chemotherapy had a higher response rate compared to single agents used in the different cooperative protocols.

Adenocarcinoma↗
PubMed1975

Effects of afferent volleys from the limbs on the discharge patterns of interpositus neurones in cats anaesthetized with alpha-chloralose.

1. In cats anaesthetized with alpha-chloralose, micro-electrodes have been used to record the discharge patterns of single neurones in the region of the nucleus interpositus. 2. Almost all cells tested could be antidromically invaded following electrical stimulation of the contralateral red nucleus, showing that they were cerebellar efferent neurones. 3. A little over half of the interpositus neurones were spontaneously active, usually at rates of less than 20 impulses/sec. 4. About 40% of the cells had no spontaneous activity, although they gave brisk responses to electrical stimulation of cutaneous nerves. Such silent units were encountered most frequently in the earlier stages of an experiment, but a number were found more than 15 hr after the beginning of an experiment. 5. Stimulation of cutaneous and mixed nerves of the fore and hind limbs provoked impulse discharges of the cells and also produced phases of deceleration of the resting discharge of spontaneously firing cells. 6. The typical response of an interpositus neurone consisted of a short latency (6-35 msec) discharge, usually separated from a long latency (50-500 msec) discharge by a period of inhibition or return to the resting discharge rate. The two phases of excitation appeared to be independently generated, since in a number of cells one phase appeared without the other. In addition, the later phase of excitation was abolished in all cells tested by a small dose of pentobarbitone which produced very little effect on the earlier phase. The long latency response was quantitatively much greater, sometimes consisting of 50 or more impulses in a response which lasted several hundred msec, but was very variable from one trial to another. 7. The long latency discharge and sometimes the preceding inhibition could readily be mimicked by single shock stimulation of the region of the contralateral inferior olive. Short latency discharges were, however, rarely evoked by olivary stimulation. 8. It is suggested that the short latency responses of the interpositus neurones were a result of synaptic excitation via cerebellar afferents, while the ensuing inhibition was a result of post-synaptic inhibition resulting from the Purkinje cell excitation due to the afferent volleys. It is suggested that the long latency excitation is due to the afferent volleys. It is suggested that the long latency excitation is due at least in part to disinhibition resulting from long pauses in Purkinje cell firing following their activation by climbing fibre afferents. 9. The possibility that these long latency responses have a physiological significance in relation to locomotion is discussed.

Action Potentials↗