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Biomedical subjects

D Cannon

Publications and source records attributed to D Cannon.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effects of increased cardiac output on pulmonary blood flow distribution during lobar ventilation hypoxia and collapse.

Electromagnetic flow probes were placed around the pulmonary artery and left lower lobe artery in anaesthetized open-chest dogs in order to measure possible changes in the ratio of lobar-to-total pulmonary blood flow (Ql/Qt) in response to changes in cardiac output produced by the opening of arterio-venous fistulae or fluid loading. Ventilation of the lobe with 7% oxygen or lobar collapse reduced Ql/Qt by 35% and 42%, respectively, but there were no significant changes in Ql/Qt in response to increases in Qt of 29-133%. It is concluded that the changes in Qt, pulmonary vascular pressures and mixed venous PO2 within the range studied did not influence Ql/Qt.

Animals↗
PubMed1986

Effect of lignocaine and nitrous oxide on hypoxic pulmonary vasoconstriction in the dog constant-flow perfused left lower lobe preparation.

The effects of lignocaine hydrochloride on hypoxic pulmonary vasoconstriction in the presence and absence of nitrous oxide were examined during constant-flow perfusion of the left lower lobe. Lignocaine had no effect on lobar pulmonary vascular resistance during lobar ventilation with oxygen or 7% oxygen in nitrogen. The substitution of nitrous oxide for nitrogen diminished the hypoxic vasoconstrictor response, whilst the subsequent infusion of lignocaine during 7% oxygen in nitrous oxide increased the response to a value which was not significantly different from that produced by 7% oxygen in nitrogen alone.

Animals↗
PubMed1986

Reversal of nitrous oxide-induced depression of hypoxic pulmonary vasoconstriction by lignocaine hydrochloride during collapse and ventilation hypoxia of the left lower lobe.

The blood flow to the left lower lobe (QL), and total (QT) pulmonary blood flow, were measured in 10 open-chest dogs using electromagnetic flowmeters. Ventilation of the left lower lobe with 7% oxygen in nitrogen produced a greater reduction in QL/QT (41%) than lobar ventilation with 7% oxygen in nitrous oxide (33%). Lobar collapse reduced QL/QT by 65%, but there was no change in QL/QT when 50% nitrous oxide was administered to the right lung. The i.v. infusion of lignocaine hydrochloride during ventilation of the lobe with 7% oxygen in nitrogen produced no change in QL/QT. However, lignocaine infusion during lobar ventilation with 7% oxygen in nitrous oxide produced a further reduction in QL/QT to a value which was not significantly different from that observed during ventilation with 7% oxygen in nitrogen. Lignocaine had no effect on QL/QT during lobar collapse whether the right lung was ventilated with 50% oxygen in nitrogen or 50% oxygen in nitrous oxide. It is concluded that lignocaine reverses the depression of hypoxic pulmonary vasoconstriction produced by lobar ventilation with nitrous oxide.

Animals↗
PubMed1985

Immunoreactive substance P and LH-RH content in median eminence and pituitary gland during proestrus, oestrus, lactation and after anterior hypothalamic deafferentation.

Substance P (SP) and luteinizing hormone releasing hormone (LH-RH) content were measured by radioimmunoassay in median eminence of female rats, SP only in rats pituitary after decapitation on the day of oestrus (E), on the first and second day of dioestrus (D1 and D2), on the day of proestrus (P) and in "constant oestrus" (AD) caused by anterior hypothalamic deafferentation and in lactation (L). During four days of oestrus cycle the highest SP and LH-RH content of median eminence was found in dioestrus. Both during cyclic oestrus and "constant oestrus", SP and LH-RH were significantly lower than on the second day of dioestrus. These results may suggest the reciprocal functional relation of both hypothalamic peptides in the mechanism of the control of gonadotropin release. The highest LH-RH concentration of the median eminence was found in the animals on the 11th to 15th day of lactation, while the SP content in the median eminence of these animals is not significantly different from those of the remaining groups except the value for dioestrus (D2) rats. The SP content in pituitary of lactating rats was significantly higher than those of rats during cyclic or "constant oestrus".

Animals↗
PubMed1984

Delayed reaction to the Dacron buttress used in urethropexy.

Eleven patients developed a delayed reaction to the Dacron buttress used in Stamey urethropexy. The reaction was characterized by pain, dyspareunia, vaginal discharge and/or bleeding, induration of the abdominal incision, vaginal granulation tissue and draining abdominal or vaginal sinus tracts. This complication occurred in 5% of the 163 patients we treated with the Stamey procedure for stress urinary incontinence. Treatment consisted of removal of the nylon suture and Dacron buttress. None of the 11 patients developed recurrent incontinence. The subjective cure rate for stress urinary incontinence was 92% using the Stamey procedure.

Adult↗
PubMed1982

Immunoreactive substance P content in median eminence and pituitary gland during oestrus, dioestrus and after anterior hypothalamic deafferentation.

The aim of the present study was to find a relation between the Substance P (SP) content in the median eminence and the pituitary gland in rats and hypothalamic regulaton of the oestrus cycle. SP content was measured by radioimmunoassay in female rat pituitary and median eminence during oestrus, dioestrus and after anterior hypothalamic deafferentation. SP content in rat's pituitary did not vary significantly among individual groups of animals. The greatest average SP content in rat's median eminence was found in dioestrus. Both during cyclic and constant oestrus resulting from anterior hypothalamic deafferentation SP content in median eminence was lower than in dioestrus. This fact indicates the possibility of SP involvement in the control of cyclic LH-RH release from hypothalamus.

Animals↗
PubMed1982

Nonoperative treatment of the acute tear-drop fracture of the cervical spine.

The tear-drop fracture is a severe injury to the cervical spine often associated with severe cord damage. Previous authors have reported high rates of instability after nonoperative treatment of this injury and have recommended early surgical fusion. During the period from January 1978 to December 1979, ten patients with acute tear-drop fractures were treated nonoperatively. Only one required surgical fusion because of latent instability. Contrary to previous reports, adequate stability of the cervical spine was achieved nonoperatively when the spinal canal had been adequately realigned by a closed method of treatment.

Adult↗
PubMed1980

Substance P in ovarian carcinoid.

A high content of substance P (124 ng/g wet tissue) was demonstrated by radioimmunoassay in lymph node metastases in a patient with bilateral ovarian carcinoid tumours. The plasma substance P level was elevated but urinary 5-hydroxyindoleacetic acid (5-HIAA) was low. It is suggested that, in some carcinoid patients, an elevated plasma substance P level may help diagnosis and follow-up when urinary 5-HIAA is normal.

Adult↗
PubMed1979

Substance P plasma levels in pregnancy and in various clinical disorders.

Using radioimmunoassay, immunoreactive SP (iSP) has been measured in the plasma of 162 hospital patients with various disorders and in the plasma of 67 pregnant women. In pregnancy, iSP was undetectable in 40% women as compared to 12% in other hospital patients. The mean iSP plasma level in pregnancy was 37.8 +/- 4.6 (SEM) as compared to 77.1 +/- 4.9 (SEM) pg/ml in other hospital patients. The results support earlier observations based on bioassay, suggesting that the blood of pregnant women contains higher concentrations of a SP-inactivating factor. Of the hospital patients, elevated levels of iSP were found in patients with chronic leukaemia, in one patient with a basaloid carcinoma of the anus, and in one patient with toxic liver damage and pancreatic insufficiency. No correlation was found between thyroid function and iSP plasma levels. ISP plasma levels in various gastrointestinal disorders were similar to those found in normal subjects.

Cystic Fibrosis↗
PubMed1979

A cholecystokinin-like peptide in crude substance P from human and bovine brain.

The subfractions of crude substance P (SP), Fa, Fb, and Fc, were assayed for SP-like activity (SP-LA) and cholecystokinin octapeptide-like activity (CCK-8-LA) using radioimmunoassays (RIAs) and bioassays. Crude SP preparations from total human and bovine brains, cortex, and subcortex (amygdala, substantia nigra) contain CCK-8-LA as well as SP-LA. Most of SP-LA was contained in Fb, whereas most of CCK-8-LA was in Fc. Fa gave ambiguous results. Pharmacological results previously obtained with Fc may reflect the activity of CCK-like peptide(s).

Animals↗
PubMed1978

Crude substance P from brain contains a cholecystokinin-like peptide.

The subfractions Fa, Fb, and Fc of crude substance P (SP) preparations made from human and bovine brains were analysed for SP and the COOH-terminal octapeptide of cholecystokinin (CCK-8). The methods were specific radioimmunoassays (RIAs) for SP and CCK-8, and bioassays on isolated organs of the guinea pig: the ileum, the gallbladder and the field-stimulated vas deferens. 1. In bioassays of synthetic peptides the vas deferens reacted specifically to SP and the gallbladder to CCK-8. 2. RIAs and bioassays revealed unequivocally that most of SP-like activity was present in Fb, while Fc contained mainly CCK-8-like activity. Varying results were obtained with Fa. 3. The pharmacologically active principle of Fc is CCK-8 or a closely related peptide. Earlier results concerning the pharmacological and neurochemical properties of Fc must be ascribed to this peptide.

Animals↗