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Biomedical subjects

R Woods

Publications and source records attributed to R Woods.

At least 19 recordsLinked to original sources
PubMed1996

Brain metabolism patterns are sensitive to attentional effort associated with a tone recognition task.

Using positron emission tomography with the tracer 18-fluoro-D-deoxyglucose, we assessed regional cerebral glucose utilization patterns (rCMRglu) associated with three performance levels in a forced choice, tone recognition task. Four normal subjects responded with one hand when they heard a high-frequency tone (1500 Hz), and with the other hand when they recognized a low-frequency tone (750 Hz). The EASY (EAS) condition accuracy average was 96%, the INTERMEDIATE level accuracy averaged 89%, and the DIFFICULT (DIF) recognition task accuracy average was 77%. Statistical parametric mapping (SPM94) analysis revealed that the DIF minus EAS contrast is associated with a marked metabolic elevation in the right middle and inferior temporal gyri and the gyrus fusiformis. The EAS minus DIF contrast revealed greater rCMRglu in the right medial geniculate body. Enhanced activity in right temporal lobe structures may reflect a role in auditory memory and "image" visualization. The medial geniculate enhancement may reflect tone frequency assessment.

Adult↗
PubMed1996

Use of the respiratory stimulant doxapram in southern elephant seals (Mirounga leonina).

The use of doxapram to stimulate breathing was examined in southern elephant seals chemically restrained with ketamine and xylazine. Animals which were breathing spontaneously received doxapram (approximately 0.5, 1, 2, or 4 mg/kg) or saline into the extradural intravertebral vein. Doxapram caused a dose-dependent increase in the depth and rate of respiration which began within one minute, peaked after two minutes and lasted for up to five minutes. A dose of 2 mg/kg appeared to be safe and effective for the stimulation of respiration, while 4 mg/kg caused arousal and shaking. Doxapram (2 mg/kg) was tested on 14 occasions in animals which had developed apnoea during chemical restraint. Doxapram had no effect when administered into the extradural intravertebral vein and appeared to be of more benefit when administered directly into the lungs via an endotracheal tube, but it was not effective in all cases. There was evidence to suggest that the endotracheal tube prevented some of the animals from breathing. The effect of intubation and endotracheal doxapram administration was therefore examined in 19 apnoeic and 31 spontaneously breathing seals. Intubation induced apnoea in animals at low levels of chemical restraint and endotracheal doxapram was unreliable for the stimulation of breathing.

Animals↗
PubMed1996

Chemical restraint of southern elephant seals (Mirounga Leonina); use of medetomidine, ketamine and atipamezole and comparison with other cyclohexamine-based combinations.

A study was conducted to assess the effectiveness of the alpha-2 agonist medetomidine for sedation of pre-moulting, mature female southern elephant seals (Mirounga leonina). Two animals were sedated with a single intramuscular dose of medetomidine (0.013 and 0.027 mg kg-1). A further two groups of five animals received medetomidine (0.017 mg kg-1) combined with ketamine (1.90 mg kg-1) and, 20 min later, either saline or the alpha-2 antagonist atipamezole (0.04 mg kg-1) intravenously. Medetomidine alone did not give sufficient restraint to permit intravenous access. The response appeared to be similar to previous findings with ketamine and xylazine. Administration of atipamezole had little effect upon the level and timecourse of restraint. Ketamine and medetomidine seem to offer few advantages over ketamine and xylazine or other cyclohexamine-drug combinations for routine chemical restraint of southern elephant seals.

Anesthetics, Dissociative↗
PubMed1996

Anal pathology in patients with Crohn's disease.

BACKGROUND: A distinctive feature of patients suffering from Crohn's disease is a predisposition to develop a variety of anal complications. The aetiology of such conditions is unclear, and the reported incidence of anal involvement in Crohn's disease varies party due to the various criteria used for classification. This study aims to review the management of patients with symptomatic anal pathology associated with Crohn's disease at St Vincent's Hospital, Melbourne. METHODS: A database of 306 patients with Crohn's disease referred to the department between January 1978 and October 1994 was reviewed to identify those patients with symptomatic anal disease. The anal pathology was recorded and classified. Demographic data and the clinical and surgery history of the patient were recorded. RESULTS: Of the 306 patients with Crohn's disease, 129 (42.4%) were identified as having symptomatic anal pathology. Patients were likely to present with anal symptoms after they had been diagnosed as having intestinal Crohn's disease (46.1%). The commonest presentations were perianal abscess (29.5%), anal fissure (27.6%), and low anal fistula (26.7%). A minority of patients presented with high/complex anal fistulae (3.8%), or recto-vaginal fistulae (5.2%). Five per cent of patients had Crohn's disease localized to the anal area. The pattern of intestinal disease in the remaining patients was small bowel 21.1%. small bowel and colon 31.9%, and colon 43.0%. A total of 244 local anal and surgical procedures were performed on these patients; the commonest of these were drainage of an abscess (38.5%), examination under anaesthetic (29.1%), and laying open of a low anal fistula (22.5%). Following surgical treatment, the recurrence rate for perianal abscesses was 13%, and for low anal fistulae 6%. CONCLUSIONS: The majority of patients with Crohn's disease who develop anal pathology have an excellent prognosis. A minority of patients develop complex anal complex anal fistulae and these remain a therapeutic challenge.

Adult↗
PubMed1995

A placental clock controlling the length of human pregnancy.

We report the existence of a 'placental clock', which is active from an early stage in human pregnancy and determines the length of gestation and the timing of parturition and delivery. Using a prospective, longitudinal cohort study of 485 pregnant women we have demonstrated that placental secretion of corticotropin-releasing hormone (CRH) is a marker of this process and that measurement of the maternal plasma CRH concentration as early as 16-20 weeks of gestation identifies groups of women who are destined to experience normal term, preterm or post-term delivery. Further, we report that the exponential rise in maternal plasma CRH concentrations with advancing pregnancy is associated with a concomitant fall in concentrations of the specific CRH binding protein in late pregnancy, leading to a rapid increase in circulating levels of bioavailable CRH at a time that coincides with the onset of parturition, suggesting that CRH may act directly as a trigger for parturition in humans.

Biological Clocks↗
PubMed1995

Crohn's disease: a colon and rectal department experience.

This study reviewed a series of patients with Crohn's disease managed by surgeons of the Department of Colon and Rectal Surgery, St Vincent's Hospital, Melbourne, since 1978. There were 306 patients: 171 males and 135 females. The mean age at diagnosis was 33.4 years (ranger 11-93). The distribution of the disease was small bowel 32.3%, small bowel and colon 26.5%, colon 39.9%, and anal disease alone 1.6%. A total of 416 abdominal operations were performed on 204 patients. The commonest indications for surgery were failed medical therapy (21.9%), small bowel obstruction (15.9%), enteric fistula (10.1%), and intra-abdominal abscess (10.1%). The most frequently performed procedures were ileocolic resection with anastomosis (28.8%), small bowel resection (9.4%), and total colectomy and ileostomy (7.0%). Postoperative complications included anastomotic leaks in 4.0%, intra-abdominal abscess formation in 3.6%, and enterocutaneous fistulae developed in 6%. Three patients died during the review period. During follow up (mean 84.4), 30% of patients developed recurrence requiring further surgery at a mean of 72.7 months postoperatively. The most frequent site for a recurrence was the pre-anastomotic terminal ileum (61.7%). In conclusion, the majority of patients with Crohn's disease will require resectional surgery at some stage. This can be performed with a low mortality and morbidity, and a recurrence rate of around 5% per year.

Adolescent↗
PubMed1995

Antagonism of some cyclohexamine-based drug combinations used for chemical restraint of southern elephant seals (Mirounga leonina).

This study examined the use of 4 antagonists of chemical restraint in mature female southern elephant seals (Mirounga leonina) that were restrained with ketamine and diazepam, ketamine and xylazine, or tiletamine and zolazepam. The antagonists were: 4-aminopyridine, yohimbine, doxapram and sarmazenil. The effects of the antagonists on the animal's time to first movement forward and recovery, heart rate, respiratory rate and venous blood gas and pH values, and level of chemical restraint were recorded. Sarmazenil (1.0 mg/kg) and doxapram (5.0 mg/kg) partially antagonised 50:1 ketamine: diazepam (ketamine = 3.0 mg/kg, diazepam = 0.06 mg/kg) and tiletamine and zolazepam (tiletamine = 0.5 mg/kg, zolazepam = 0.5 mg/kg). However, the rapid recovery after low doses of anaesthetics means that antagonism is usually unnecessary, and it may increase the likelihood of shaking. Routine antagonism of ketamine and xylazine (ketamine = 3.0 mg/kg, xylazine = 0.5 mg/kg) is more useful given its usually delayed recovery time and potential for thermoregulatory problems. For this purpose yohimbine (0.06 mg/kg) offered advantages over doxapram in giving a smoother recovery with less aggression. 4-aminopyridine (0.2 mg/kg) prolonged chemical restraint by 100:1 ketamine:diazepam (ketamine = 3.0 mg/kg, diazepam = 0.03 mg/kg) and ketamine and xylazine, and should be contraindicated. Doxapram (5.0 mg/kg) was the most useful general antagonist for all groups of drugs but shaking was seen and a lower dose is recommended.

4-Aminopyridine↗
PubMed1995

Tuberculosis in a wild Australian fur seal (Arctocephalus pusillus doriferus) from Tasmania.

Tuberculosis was found in a wild, mature male Australian fur seal (Arctocephalus pusillus doriferus) at Hobart, Tasmania on 8 March 1992. We observed fibrogranulomatous and pyogranulomatous lesions in the lung, pleura, lymph nodes and spleen. The SDS/PAGE profile of this Tasmanian isolate was similar to other seal strains; however, differences were detected using pTBN12 and insertion sequence IS6110 probes.

Animals↗
PubMed1994

Use of midazolam, pethidine, ketamine and thiopentone for the restraint of southern elephant seals (Mirounga leonina).

Thirty-two pre-moulting female southern elephant seals (Mirounga leonina) were heavily sedated with midazolam (0.04 mg/kg) combined with pethidine (4 mg/kg). This combination made it possible to give the seals intravenous injections and was rapidly antagonised by naloxone. After sedation with midazolam and pethidine, 2 to 3 mg/kg intravenous thiopentone or ketamine induced light immobilisation for approximately five minutes and allowed the animals to be intubated. Prolonged deep levels of restraint were achieved after sedation with midazolam and pethidine by repeated intravenous doses of approximately 1.5 mg ketamine/kg at 10 minute intervals, to maintain restraint for 60 minutes.

Animals↗
PubMed1994

Mapping motor representations with positron emission tomography.

Brain activity was mapped in normal subjects during passive observation of the movements of an 'alien' hand and while imagining grasping objects with their own hand. None of the tasks required actual movement. Shifting from one mental task to the other greatly changed the pattern of brain activation. During observation of hand movements, activation was mainly found in visual cortical areas, but also in subcortical areas involved in motor behaviour, such as the basal ganglia and the cerebellum. During motor imagery, cortical and subcortical areas related to motor preparation and programming were strongly activated. These data support the notion that motor learning during observation of movements and mental practice involves rehearsal of neural pathways related to cognitive stages of motor control.

Adult↗
PubMed1993

A prospective randomised study of local versus general anaesthesia for cataract surgery.

One hundred and sixty-nine patients (aged 65-98 years) were randomised to receive either local or general anaesthesia for cataract surgery. Cognitive function was assessed using a battery of psychometric tests performed pre-operatively, and at 24 h, 2 weeks and 3 months postoperatively. Oxygen saturation, blood pressure and heart rate were monitored and the results recorded throughout the anaesthetic and immediate recovery period. In the general anaesthetic group, 19% of patients experienced at least one episode of oxygen desaturation during the procedure compared with none in the local anaesthetic group. Pulse rate and blood pressure were stable in the local anaesthetic group compared with the general anaesthetic group where marked fluctuations were noted; 61% of patients in the general anaesthetic group experienced falls in systolic blood pressure greater than 30% of the pre-induction value. No evidence of long-term postoperative cognitive dysfunction was detected and there was no significant difference between the performances of the two groups.

Aged↗
PubMed1993

Oral herpes remission and fluoride pulsing. Case reports.

Based on evidence from observation of some twenty cases, there would appear to be a relationship between the incidence and severity of herpes simplex attacks and the ingestion of daily fluoride in the form of tablet supplementation. Although only anecdotal at present, the cases presented seem to indicate that children who had previously suffered from recurrent herpes entered into a period of partial or complete remission when receiving daily fluoride tablet supplementation. Further observations are needed to confirm this relationship.

Adult↗
PubMed1991

Bacon's chicken.

Explore the source record for details and available documents.

Food Preservation↗
PubMed1991

Intravaginal prostaglandin E2 gel and cardiovascular changes in hypertensive pregnancies.

Prostaglandin E2 (PGE2) and its analogues may be potent vasodilators, and intravaginal PGE2 is known to be absorbed rapidly into the maternal circulation. This study investigated any cardiovascular effects from intravaginal PGE2 on 42 hypertensive pregnant women requiring preinduction cervical ripening. Declines in maternal diastolic, systolic, and mean arterial pressures were apparent during the first half hour. This trend was mild, was reversible without treatment, and did not influence the fetal heart rate baseline or patterns. Fear of clinically significant changes should not be a concern, but monitoring during the first hour is recommended.

Administration, Intravaginal↗