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Biomedical subjects

A McFarlane

Publications and source records attributed to A McFarlane.

At least 19 recordsLinked to original sources
PubMed1998

Psychiatric disorder and disability in a rural community.

This study examined the relationship between psychiatric disorder and disability in a rural community and the use of formal and informal services in the management of such disabilities. It was found that of the 26% of the surveyed population who obtained a positive current psychiatric diagnosis, 48.3% had required assistance in managing at least one activity of daily living. The majority of those seeking assistance in managing these functional problems did so from family and friends rather than from formal agencies. Psychiatric disorder was found to lead to disability as frequently as did physical disorder, with almost 50% of those who had experienced mental health problems reporting that they were currently unable to carry out at least one activity of daily living. The finding that assistance was sought primarily from family and friends raises important questions about the nature of psychiatric disorder as a public health problem.

Activities of Daily Living↗
PubMed1998

Fluid abnormalities occur in the chronically cannulated mid-gestation but not late gestation ovine fetus.

Hydrops fetalis, with or without oligo- or polyhydramnios, is associated with very high fetal mortality. In many cases the causes are unknown. Chronically cannulated ovine fetuses have been used as animal models to study the regulation of fetal fluid balance. This study reports that the mid-gestation ovine fetus (70 +/- 1 d of gestation; term = 145-150 d) is susceptible to the development of fetal abnormalities (excess allantoic fluid--hydrallantois, with or without hydrops and hydranencephaly), when blood vessels in the neck are cannulated. Cannulation of one carotid artery and one jugular vein, or cannulation of a single jugular vein resulted in 5 out of 12 fetuses having abnormalities 1 wk later. In contrast, six fetuses at 115 d of gestation that had both carotids and one jugular vein ligated cranially and cannulated, developed hydranencephaly but no hydrops or hydrallantois. In the mid-gestation fetus hydrallantois [760 +/- 140 mL (n = 5) versus 104 +/- 23 mL (n = 7 controls), p < 0.001] occurred without alterations in the plasma concentrations of ACTH, cortisol, atrial natriuretic peptide, or aldosterone, as well as without anemia. Although the causes of the fluid abnormalities were not resolved, it is important to note the developmental differences in vulnerability.

Adrenocorticotropic Hormone↗
PubMed1997

The phenomenology of traumatic reactions to psychotic illness.

This study investigated whether a psychotic illness was associated with posttraumatic stress disorder (PTSD) symptomatology in 45 subjects recovering from hospitalization for a psychotic episode. Previous studies have suggested that the experience of psychosis and hospitalization is distressing and that PTSD may be a useful paradigm for the psychological response. Subjects were given questionnaires to evaluate PTSD symptoms, anxiety symptoms, and distress and intrusive memories associated with aspects of treatment and psychosis. Treatment, especially experiences involving a loss of control such as detention, and psychotic symptoms, particularly persecutory delusions, passivity phenomena, and visual hallucinations, were perceived as highly distressing. Twenty-two subjects (52%) met the criteria for a postpsychotic PTSD, with implications for recognition and management of secondary morbidity related to psychosis.

Adaptation, Psychological↗
PubMed1996

Experimental hydranencephaly in the ovine fetus.

Hydranencephaly is defined as the replacement of a previously normal brain, in whole or in part, by membranous fluid-filled sacs. The etiology is not well understood, and the time course of development is unknown. Fifteen ovine fetuses were chronically cannulated and had both carotid arteries ligated at 100 days of gestation (term is 145-150 days). They were killed at 1 (n = 4), 2 (n = 6) and 4 (n = 5) weeks post-surgery, and the findings compared with those of 25 age-matched controls. By 2 weeks post-surgery the entire cerebral hemispheres and diencephalon had been replaced by fluid closely resembling cerebrospinal fluid. The choroid plexus, pituitary and brain stem remained outwardly normal, but the cerebellum showed signs of damage. Fetuses maintained normal values for blood gases and hematocrit up to 4 weeks post-surgery, and grew normally. Light microscopy of the brain stem showed significant losses of cell populations in the medulla by 4 weeks. Vascular casting and acute blood flow studies in an additional group of fetuses showed that the entire brain was perfused via the vertebral-occipital anastomosis immediately after acute bilateral carotid clamping, but that the blood flow rate was insufficient to maintain adequate oxygen delivery.

Animals↗
PubMed1996

Dissociation, somatization, and affect dysregulation: the complexity of adaptation of trauma.

OBJECTIVE: A century of clinical research has noted a range of trauma-related psychological problems that are not captured in the DSM-IV framework of posttraumatic stress disorder (PTSD). This study investigated the relationships between exposure to extreme stress, the emergence of PTSD, and symptoms traditionally associated with "hysteria," which can be understood as problems with stimulus discrimination, self-regulation, and cognitive integration of experience. METHOD: The DSM-IV field trial for PTSD studied 395 traumatized treatment-seeking subjects and 125 non-treatment-seeking subjects who had also been exposed to traumatic experiences. Data on age at onset, the nature of the trauma, PTSD, dissociation, somatization, and affect dysregulation were collected. RESULTS: PTSD, dissociation, somatization, and affect dysregulation were highly interrelated. The subjects meeting the criteria for lifetime (but not current) PTSD scored significantly lower on these disorders than those with current PTSD, but significantly higher than those who never had PTSD. Subjects who developed PTSD after interpersonal trauma as adults had significantly fewer symptoms than those with childhood trauma, but significantly more than victims of disasters. CONCLUSIONS: PTSD, dissociation, somatization, and affect dysregulation represent a spectrum of adaptations to trauma. They often occur together, but traumatized individuals may suffer from various combinations of symptoms over time. In treating these patients, it is critical to attend to the relative contributions of loss of stimulus discrimination, self-regulation, and cognitive integration of experience to overall impairment and provide systematic treatment that addresses both unbidden intrusive recollections and these other symptoms associated with having been overwhelmed by exposure to traumatic experiences.

Adaptation, Psychological↗
PubMed1995

Cortisol feedback in adrenalectomized adult sheep.

These experiments tested the sensitivity of cortisol feedback on adrenocorticotropic hormone (ACTH) secretion in adult sheep. In series I, five bilaterally adrenalectomized (ADX) adult sheep were maintained on "low" (125 micrograms/h) or "high" (500 micrograms/h) intravenous cortisol replacement, and dose-response curves were obtained with corticotropin-releasing factor (CRF) and arginine vasopressin (AVP). CRF caused incremental increases in plasma ACTH at the low but not the high dose of cortisol. AVP was similarly ineffective in stimulating ACTH at the high dose of cortisol. However, in series II, where ADX animals were again maintained on low or high cortisol infusions, a combined infusion of CRF and AVP was able to stimulate a robust ACTH response during both steroid replacement regimens. These studies demonstrate that the pituitary represents a major site of steroid feedback in the sheep, with a relatively small increase in the concentration of cortisol, within the normal unstressed physiological range, being able to inhibit ACTH secretion in response to exogenous CRF and AVP. However, under these conditions, inhibition of ACTH release can be overcome by the combined action of CRF and AVP. Further studies in series III, concerned with the nature of glucocorticoid inhibition of AVP release, demonstrate that whereas exposure to maximal cortisol levels (5,000 micrograms/h) completely abolishes the ACTH response to severe hemorrhage (15 ml/kg over 15 min), AVP release is maintained, suggesting that the system controlling AVP release during hemorrhagic stress is less sensitive to the negative influences of glucocorticoids than is the system controlling ACTH release.

Adrenalectomy↗
PubMed1995

Corticotropin-releasing factor alone, but not arginine vasopressin alone, stimulates the release of adrenocorticotropin in the conscious intact sheep.

These studies compared the relative potencies of CRF and arginine vasopressin (AVP) as ACTH secretagogues in the sheep. Dose-response curves to CRF (10, 25, 50, and 100 micrograms/h) and AVP (0.3, 1.0, 3.0, and 10.0 micrograms/h) were obtained in five adult sheep, with arterial blood samples taken for CRF, AVP, ACTH, and cortisol measurements to determine the pituitary-adrenal response. It was found that the first dose of CRF increased plasma CRF levels to 444 +/- 79 pg/ml. ACTH levels rose significantly from 28 +/- 5 to 186 +/- 46 pg/ml, with a concurrent rise in cortisol levels from 7 +/- 3 to 44 +/- 9 ng/ml. Although plasma ACTH and cortisol levels remained elevated, higher doses of CRF failed to produce further increases. AVP, at all of the doses studied, did not produce an increase in ACTH levels, although cortisol levels rose significantly by the second dose. In a second series of experiments, animals received a continuous infusion of CRF (10 micrograms/h) alone or in combination with graded doses of AVP (0.3, 1.0, 3.0, and 10.0 micrograms/h for 60 min each). It was found that AVP at the highest dose was able to potentiate the ACTH response to CRF. Lower doses of AVP, which did not stimulate a further increase in ACTH levels were, however, associated with a significant rise in cortisol levels. In conclusion, it was found that although CRF alone was a potent stimulator of ACTH secretion, AVP at the doses studied was not able to elicit an ACTH response in the conscious intact sheep. However, a dose of AVP that was not stimulatory in itself was able to augment the ACTH response to CRF.

Adrenocorticotropic Hormone↗
PubMed1994

Effect of maternal glucocorticoid treatment on fetal fluids in sheep at 0.4 gestation.

Treatment of nine pregnant Merino ewes (64.0 +/- 0.4 days of gestation) with dexamethasone (D; 0.76 mg/h for 48 h) resulted in significant alterations in fetal fluids compared with eight saline-infused control animals (S; 63.0 +/- 0.9 days). There was a substantial increase in allantoic fluid volume (177 +/- 18 ml, D vs. 31 +/- 6, S) but no change in amniotic fluid volume (248 +/- 12 ml, D; 305 +/- 24, S). For allantoic fluid there was a significant decrease in osmolality (213 +/- 4 mosmol/kg water, D; 230 +/- 5, S) and alterations in composition. Amniotic fluid osmolality was unchanged (292 +/- 2 mosmol/kg water, D; 293 +/- 1, S), but amniotic fluid composition was affected. In four fetuses in which bladder and amniotic cannulas were inserted at gestational age 68-75 days, fetal urine flow rate increased from a mean of 4.1 +/- 1.1 to 13.8 +/- 2.6 ml/h after 24 h and 11.8 +/- 3.0 ml/h at 48 h for a similar maternal D infusion, whereas no such increase occurred in four control fetuses. All the fetal urine voided during a 3.5- to 4-h infusion of 51Cr-labeled EDTA into the fetal bladder was directed to the allantois. The results suggest that the increase in allantoic fluid volume resulted from increased fetal urine output into the allantoic compartment, although the composition of the excess allantoic fluid differed substantially from that of fetal urine. There was a greater incidence of abnormal cotyledons in the D-infused ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantoin↗
PubMed1993

Abnormalities of foetal fluids in sheep: two case reports.

Two cases of abnormal accumulation of foetal fluids in sheep are described. In the first case, a ewe, at 64 days of pregnancy, had 2 sacs of fluid, one at each of the tips of the pregnant and non-pregnant horns. Neither sac contained a foetus. The composition of the fluids differed from those of the amniotic and allantoic fluids associated with a single foetus. The composition resembled that of foetal plasma. We conclude that the 2 sacs were amniotic sacs from conceptuses that had been resorbed, and that at this early (0.4) stage of pregnancy, amniotic fluid can accumulate in the absence of a viable foetus. The second case was a rare case of hydrallantois in a ewe at 100 days of pregnancy. The volume of allantoic fluid (1800 mL) was more than 10 times normal. The composition was normal, except for high chloride and calcium concentrations and a very low creatinine concentration. The foetus and the volume and composition of the amniotic fluid were normal. The hydrallantois might have occurred as a result of some alteration in function of the allantoic membrane, perhaps as a result of altered hormonal status of the ewe.

Allantois↗
PubMed1986

How does dietary lipid lower blood alcohol concentrations?

To determine the mechanism, whereby food lowers blood alcohol concentrations, gastric emptying and blood alcohol profiles were measured in six healthy male volunteers after they had drunk a 200 ml solution of vodka and orange juice containing 0.5 g/kg alcohol. Subjects were studied on two separate occasions during infusion of isosmotic solutions of either Intralipid or saline into the ileum via an intestinal tube. Gastric emptying was significantly delayed by ileal infusion of fat emulsion and the peak blood alcohol concentration was significantly depressed. Similar effects were observed in three subjects when the solutions were infused into the duodenum. These results suggest that the reduction in alcohol absorption by food does not depend on the physical relationship between the alcohol and the food or between the food and the absorbing epithelium, but is probably caused by a delay in the delivery of alcohol to the small intestine, from where it is rapidly absorbed.

Adult↗
PubMed1985

Interpretation of the breath hydrogen profile obtained after ingesting a solid meal containing unabsorbable carbohydrate.

The extent to which monitoring breath hydrogen excretion provides information concerning the entry of the residues of a solid test meal into the colon was investigated in 89 normal subjects, and 11 patients with the irritable bowel syndrome. The profile of breath hydrogen concentration showed an early peak, that occurred soon after ingesting the test meal in 89% subjects. This was followed by a later more prolonged rise in breath hydrogen concentration. The early peak occurred well before a radioactive marker, incorporated in the test meal, reached the caecum and the data suggest it was predominantly caused by the emptying of the remnants of the previous meal from the ileum into the colon. This hypothesis was supported by direct measurements of the rate of delivery of ileostomy effluent in 12 subjects with terminal ileostomies. Fermentation of carbohydrate in the mouth may, however, contribute to the initial peak, but this contribution may be avoided by collecting gas samples from the nares. The secondary rise in breath hydrogen excretion was closely correlated with the arrival of the radioactive marker in the caecum (r = 0.91), p less than 0.001), though the time, at which the secondary peak of breath hydrogen excretion occurred was poorly correlated with the time that all the radioactive test meal had entered the colon. When lactulose was infused directly into the colon, as little as 0.5 g produced a discernible hydrogen response, which occurred within two minutes of the infusion. Increasing the rate of colonic infusion of a 50 ml solution of 10% lactulose from 0.02 to 0.15 g/min in five subjects significantly increased the breath hydrogen concentration. At infusion rates below 0.075 g lactulose/minute, the peak breath hydrogen response preceded the end ot the infusion, while at higher rates of infusion, the peak hydrogen response occurred after the end of the infusion. Although these results confirmed that monitoring breath hydrogen concentration usefully signalled the time taken for a meal containing unabsorbed carbohydrate to reach the colon, it did not reliably indicate the time when all of the meal had entered the colon. Finally, the use of the maximum increase in breath hydrogen concentration as an index of the degree of carbohydrate malabsorption assumes uniform rates of entry into the colon.

Absorption↗
PubMed1984

Methodological standards in studies evaluating the dexamethasone suppression test.

The dexamethasone suppression test (DST) has been used for several years to assist in the diagnosis of melancholia. However, recent studies have cast doubt upon the diagnostic efficacy of the test. Twenty of the original studies that assessed this application of the DST were reviewed using six methodological criteria considered essential for the evaluation of a diagnostic test. None of the papers complied with all the criteria and only seven of the papers satisfied more than three criteria. These findings suggest that methodological problems might account for discrepancies between the original claims made for the test and the current status of the test.

Depressive Disorder↗
PubMed1984

Effect of infusion of nutrient solutions into the ileum on gastrointestinal transit and plasma levels of neurotensin and enteroglucagon.

The small bowel transit time of 100 ml of lactulose solution infused at the ligament of Treitz was measured by breath hydrogen excretion in paired studies carried out in 43 healthy volunteers during infusion (1.2 ml/min) of equal volumes (100 ml) of isotonic solutions of either fat emulsion (Intralipid, Prosparol, or Calogen), protein hydrolysate, glucose, or saline into either the jejunum (90 cm from the teeth), ileum (205 cm from the teeth), or colon (350 or 400 cm from the teeth). Ileal infusion of Intralipid or protein hydrolysate resulted in significant delays in small bowel transit time (125 +/- 21 min and 71 +/- 11 min, respectively) compared with infusion of saline (50 +/- 3 min; p less than 0.02 and p less than 0.05). These delays were not associated with any significant alteration in plasma levels of neurotensin or enteroglucagon. Small bowel transit time was unaffected by infusion of nutrients into the colon or jejunum, although jejunal infusion of Intralipid increased the plasma levels of enteroglucagon and neurotensin (p less than 0.01 and p less than 0.02, respectively) after the start of lactulose infusion. In a separate series of paired experiments, infusion of Intralipid into the ileum in 5 volunteers significantly delayed the transit of a solid test meal labeled with 25 microCi of 99mTc-sulfur colloid through both the stomach and small intestine. These data support the existence of a mechanism whereby the presence of unabsorbed food in the ileum may enhance absorption by delaying the passage of food through the small intestine.

Adult↗