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Biomedical subjects

R C Sutherland

Publications and source records attributed to R C Sutherland.

17 recordsLinked to original sources
PubMed1992

Statement: occupational therapy services in work practice.

Occupational therapy practitioners focus on the individual's ability to participate in productive occupations throughout their life span. Through prevention, assessment, and intervention strategies, occupational therapy practitioners often collaborate with other members of the health care team and assist persons to optimize their ability to engage in purposeful occupation while facilitating a safe and successful entry into or return to work.

Accidents, Occupational↗
PubMed1988

Oxytocin release evoked by electrical stimulation of the medial forebrain in the rat: analysis of stimulus parameters and supraoptic neuronal activity.

The role of the medial forebrain area (vertical limb of the diagonal band, medial septum and medial nucleus accumbens) in the control of oxytocin secretion in lactating rats was investigated. Electrical stimulation of the medial forebrain evoked a reproducible rise in intramammary pressure, equivalent to that caused by i.v. injection of 1 mU oxytocin. No pressor effect accompanied this response. Radioimmunoassay of plasma samples showed that stimulation caused a significant rise in the concentration of circulating oxytocin. The effects of changing the parameters of stimulation to the medial forebrain were compared with those evoked by stimulation of the neural stalk. The optimal frequency for stimulation of the forebrain was found to be four-fold lower (10-20 Hz) than that for stimulation of the neural stalk (50 Hz). During continuous prolonged stimulation of the forebrain (20 Hz; 2 min) only a single transient response was obtained, whereas a protracted response was obtained as a result of prolonged stimulation of the stalk. Recordings were made from antidromically identified neurosecretory cells in the supraoptic nucleus. Electrophysiological responses to electrical stimulation of the medial forebrain were characterized by two main features. (1) Single-pulse stimulation produced only a small excitation (one or two action potentials), while high-frequency trains produced a profound facilitation of this response, with each pulse evoking short-duration 'bursting' behaviour in the supraoptic neurons. (2) During long trains of stimulation this frequency-dependent facilitation declined and could only be renewed after a period of rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1987

Prolonged electrical stimulation of the nipples evokes intermittent milk ejection in the anaesthetised lactating rat.

Intermittent and continuous electrical stimulation of the nipples elicited milk-ejection responses in the lactating rat. The responses occurred intermittently, with similar amplitudes and periodicity as those seen in suckled rats. The responses were always associated with synchronization of the electroencephalogram (EEG), but some rats with synchronized EEG activity did not milk eject during stimulation. Since continuous stimulation also resulted in intermittent milk ejection it seems unlikely that the periodicity of the reflex in suckled rats depends upon changes in the intensity of sensory stimulation. The techniques of nipple stimulation may be a useful method with which to study neural pathways and other phenomena such as gating involved in oxytocin release and milk ejection. The success of the technique depends on a variety of factors such as parameters of the stimulation and state of anaesthesia.

Anesthesia↗
PubMed1986

Composite lymphoma.

A case of composite lymphoma in a young female is described. The patient was found to have lymphocyte-predominant Hodgkin's disease at presentation, but subsequent staging laparotomy revealed coexistent but distinct Hodgkin's disease and diffuse large cell lymphoma in the spleen. Possible explanations for this rare occurrence are discussed, and the literature is reviewed.

Adult↗
PubMed1986

Changing characteristics of the milk-ejection reflex during pregnancy, lactation and after weaning in the rat.

The pattern of reflex milk ejection during suckling was investigated in anaesthetized Wistar rats at various stages of pregnancy, lactation and after weaning. Milk-ejection responses were measured using intramammary pressure recordings, and the amount of oxytocin released was estimated from log dose-response lines compiled from the mammary responses to exogenous oxytocin. The number of rats showing intramammary pressure responses to oxytocin increased on Day 22 of pregnancy (the day of parturition) and decreased at 8 days after weaning. The dose-response lines from pregnant animals were shallow, but steepened and shifted to the left during lactation and after weaning. Reflex milk-ejection responses during suckling were detectable in primigravid animals, indicating that birth of the litter and previous suckling experience are unnecessary for the immediate functioning of the reflex. Reflex milk-ejection responses improved during early lactation (such that the frequency and the amount of oxytocin released at each response were maximal at Day 10 of lactation), and subsequently declined in late lactation. Although the frequency of responses in animals 2 and 4 days after weaning was similar to that in late lactating animals, the amount of oxytocin released at each response had risen again to mid-lactation values. In animals undergoing a second pregnancy and lactation the pattern of change in the milk-ejection responses was similar to that of primiparous animals.

Animals↗
PubMed1985

Effects of water deprivation and deamino [8-D-arginine] vasopressin on [14C]2-deoxyglucose uptake by the hypothalamo-hypophysial system in mice with hereditary nephrogenic diabetes insipidus.

The effects of water deprivation and the injection of deamino [8-D-arginine] vasopressin (dDAVP) on the metabolic activity of the hypothalamo-neurohypophysial neurones of mice with inherited nephrogenic diabetes insipidus (DI +/+ Severe) have been investigated by quantitative autoradiography using the [14C]2-deoxyglucose (2-DG) technique. The relative metabolic activities (rma) of the paraventricular nuclei (PVN) and pars nervosa (PN) in severely diabetic mice were not significantly different from the rma of the PVN and PN in Non-severe or Normal mice, but the rma of the pars distalis (PD) was greater in the Severe mice than in the other two strains. Water deprivation (4-5 h) significantly increased the rma of the PVN and PN in Severe mice compared with those in Non-severe mice that had been similarly deprived of water. The increased rma of the PVN and PN produced by water deprivation in Severe mice was not reduced to normal by injection of dDAVP. The injection of dDAVP alone had no effect on the rma of the PVN or PN, but dDAVP injection alone, water deprivation alone, or both treatments combined decreased the rma of the PD in Severe mice. Neither the supraoptic nuclei (SON) nor any of the other 19 brain areas studied were affected, in terms of rma, by either water deprivation, injection of dDAVP, or both.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Rhabdomyosarcoma in a patient treated for metastatic germ cell tumour of the testis containing teratoma--a case report.

A patient who developed a rhabdomyosarcoma following apparently successful chemotherapy for metastatic germ cell testicular carcinoma is presented. This newly recognized association may be seen particularly in patients whose initial germ cell malignancy contains immature teratoma. Possible reasons for this are discussed. The findings in this patient suggest that re-biopsy of recurrent disease be undertaken wherever possible, particularly where immature teratoma was a feature of the initial histopathology. A proportion of relapsing patients as described may not in fact have recurrent germ cell malignancy, but may have developed high grade, and often chemoresistant sarcomas. These second tumours appear to have an extremely poor prognosis, unless amenable to complete surgical resection.

Adult↗
PubMed1985

Reappraisal of the influence of mammary distension on the frequency of milk ejection in the rat.

Experiments were performed to reinvestigate the importance of mammary engorgement for activation of the milk-ejection reflex in the rat. Reflex milk ejection (measured by intramammary pressure recordings during a 2-h suckling test under anaesthesia) was compared in rats with engorged mammary glands (15-h separation from the pups, followed by sham-removal of milk) and in rats with drained mammary glands (15-h separation, followed by milk removal using a foster litter and exogenous oxytocin). In experiment 1, multiple small (2 mu.) doses of oxytocin were used for milk removal: these were effective in emptying the mammary glands and caused no subsequent impairment or change in sensitivity of the mammary response to oxytocin. Using this draining procedure, no significant differences were observed in either the number or relative amplitude of the milk ejections, or the occurrence of pup stretch reactions between engorged and drained rats. Similar results were seen in experiment 2, where an identical draining protocol was used, but the rats were pretreated with propranolol before the suckling test. In experiment 3, large (250 mu.) oxytocin doses were used for milk removal, as in previous studies. Again mammary draining had no effect on milk ejection in a subsequent suckling test (with propranolol pretreatment). However, the number of stretch reactions shown by the pups was significantly (P less than 0.001) reduced from 8.6 +/- 1.4/2 h to 1.9 +/- 0.6/2 h. This effect probably related to long-term impairment of the oxytocin response of the mammary glands following the draining procedure, and could not be attributed to the draining per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Effect of mating on the metabolic activity of the brain and pituitary gland assessed by [14C]2-deoxyglucose in a reflex ovulator, the vole (Microtus agrestis).

The neural pathways involved in reflex ovulation in the vole (Microtus agrestis) have been investigated with the [14C]2-deoxyglucose (2-DG) method. Female voles were injected i.p. with 2-DG and either not mated, sham-mated (mounted by males by vagina was taped) or mated for a period of 45 min after the injection, after which the animals were decapitated. The brain was processed for autoradiography and the relative metabolic activities (rma) of selected areas of the brain and pituitary gland were determined. The plasma separated from trunk blood was assayed for the concentration of luteinizing hormone (LH). The lordosis quotients (LQ) were (mean +/- S.E.M.) 81 +/- 8 (n = 5) in mated compared with 47 +/- 8 (n = 5) in sham-mated voles. The rma of the midbrain central grey (CG) and reticular formation (RF) were significantly greater in mated and sham-mated voles compared with the values in unmated voles. There were no other between-group differences in the rma of the other 28 areas of the brain or pituitary gland studied in spite of the fact the plasma LH concentration in mated voles was 36.9 +/- 9.6 ng NIH-LH-S18/ml compared with undetectable (less than 2.5 ng/ml) values in all the sham-mated and unmated animals. These results show that in the vole increased metabolic activity of the CG and RF is associated with lordosis, but that the reflex release of LH is not accompanied by any significant change in the metabolic activity of the brain or the pituitary gland.

Animals↗
PubMed1984

Pulmonary hypertension complicating hepatocellular carcinoma.

A case of primary liver cell carcinoma is presented in which tumor emboli to the pulmonary microvasculature resulted in pulmonary hypertension, documented by clinical, radiologic, electrocardiographic, and cardiac catheter studies. Emboli arose from tumor invading the portal vein and passed via a patent splenorenal shunt to the systemic venous and pulmonary arterial microvasculature. Despite a prolonged clinical course (20 mo) there was no radiologic evidence of pulmonary metastases and, histologically, tumor emboli were seen to undergo organization and recanalization.

Autopsy↗
PubMed1983

The milk ejection pathway in brain studied with the 2-deoxyglucose method.

The neural pathways involved in the milk ejection reflex have been studied with the aid of the 2-deoxyglucose (2DG) method. All the experiments were carried out on Wistar female rats, 9-11 days post-partum, which had been separated from their pups (except for one) overnight. The effect of suckling on the relative metabolic activity (RMA) of the brain was studied in conscious rats and in rats anaesthetized with urethane. Control animals were similarly treated but were not suckled. In addition, the effect of mammary nerve stimulation on RMA was studied in animals anaesthetized with urethane; sham-operated animals served as controls for this group. Suckling (minimum of 10 pups) in conscious animals had no apparent effect on the RMA of any of the brain areas measured. However, in anaesthetized rats, suckling produced a significant increase in the RMA of the paraventricular and supraoptic nuclei (PVN and SON), but had no effect on the RMA of any other brain area or the pituitary gland. Stimulation of the mammary nerve, with a stimulus that causes milk ejection and an increase in prolactin release, produced a significant increase in the RMA of the PVN, SON, the pars distalis and pars nervosa and the spinothalamic tract, and a significant decrease in the ventromedial and mediodorsal nuclei of the thalamus, the zona incerta, the red nucleus and the ventral nucleus of the lateral lemniscus. These results show that suckling significantly increases the metabolic activity of afferent terminals in the PVN and SON. Activation of the cell bodies of the PVN and SON, as assessed by increased RMA of the pituitary gland, could be evoked by the more intense stimulus of mammary nerve stimulation. The ascending pathway from the mammary nerve involves the spinothalamic tract but could not be traced beyond the midbrain. The lack of effect of suckling in conscious animals may have been due to the inhibitory influence of stress mediated by forebrain structures.

Animals↗
PubMed1983

Water deprivation results in increased 2-deoxyglucose uptake by paraventricular neurones as well as pars nervosa in Wistar and Brattleboro rats.

The [14C]2-deoxyglucose (2-DG) technique has been used in conjunction with quantitative autoradiography to determine the metabolic activity of the neurones of the hypothalamo-neurohypophysial system. Water deprivation (4 days) in Wistar rats led to a more than two-fold increase in the metabolic activity of the pars nervosa (PN), and a significant increase in the metabolic activity of paraventricular (PVN) but not supraoptic (SON) neurones. The PN in homozygous Brattleboro rats was significantly more active than that in hydrated Wistar and Piebald Virol Glaxo (PVG) rats; as in Wistar rats, activity of the PN and PVN was significantly increased by 12-15 h water deprivation. The administration of desamino-D-arginine vasopressin (dDAVP) to Brattleboro rats significantly reduced the activity of the PN to that seen in hydrated Wistar and PVG rats. This reduction in activity was accompanied by a significant reduction in plasma osmolality. These results show that (1) in contrast to studies in which the osmotic stimulus was a salt load, water deprivation leads to a significant increase in 2-DG uptake by the perikarya as well as the terminals of neurohypophysial neurones; (2) increased activity of the neurohypophysial neurones occurs even when there is a genetic deficiency of vasopressin and the activity can be increased further by an osmotic stimulus, and (3) the activity of the neurohypophysial neurones can be significantly reduced by the administration of dDAVP.

Animals↗
PubMed1983

Bilateral renal oncocytomas: a case report.

We report on a man with bilateral multiple renal oncocytomas who had enlarged kidneys, and presented with loin pain and gross hematuria. A provisional diagnosis of multiple renal oncocytomas was made after renal angiography demonstrated the characteristic appearance of this tumor. The diagnosis was confirmed with histology of an open renal biopsy specimen. This case is unique in that the lesions were multiple and bilateral. The patient had impaired renal function and, hence, the necessity for conservative management once the histological diagnosis had been established. Since in previously reported cases oncocytomas have been removed completely our case provides an opportunity to observe the natural history of the disease.

Adenoma↗
PubMed1975

Endotoxin from Fusobacterium necrophorum of bovine hepatic abscess origin.

The endotoxic activity of Fusobacterium necrophorum bov 5 was investigated. The supernatant (S) fluid and cell wall (CW) preparation, obtained after differential centrifugation of the ruptured cell mass, were lethal for mice. The toxicity of the S fluid was stable during prolonged storage, treatment with formalin, and heating for 15 minutes at 80, 100, and 121 C, but was destroyed by alkaline hydrolysis with 0.25 N NaOH. The toxic factor was found in a high molecular weight (MW) fraction after gel filtration. The properties exhibited by the toxic S fluid resembled those of endotoxic lipopolysaccharide (LPS). Extracted and partially purified LPS (endotoxin) from F necrophorum bov 5 demonstrated a mouse median lethal dose (mouse LD50) of 16.8 mg/kg of body weight. The toxic LPS material, a high molecular weight moiety as estimated by gel filtration, was resistant to ribonuclease (RNase), deoxyribonuclease (DNase), and pronase treatment. A positive Shwartzman reaction (median skin lesion dose (SLD50) equal to 3.32 mug/kg of body weight) and biphasic fever response (minimal dose required to produce a fever index of 40 sq cm which falls on the linear portion of dose-response curve (FL40) equal to 0.41 mug/kg of body weight) further indicated the toxin was endotoxin in nature. The LPS from F necrophorum bov 5 was less toxic than Salmonella typhimurium LPS; but had considerable toxicity for experimental animals. The toxic activity of the partially purified F necrophorum bov 5 endotoxin was separated into 2 fraction regions by diethylaminoethyl (DEAE)-cellulose chromatography. The data provide evidence for the production of a potent endotoxin, possibly composed of more than one toxic component, which may be released upon cell disruption.

Animals↗