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Biomedical subjects

V Walker

Publications and source records attributed to V Walker.

At least 19 recordsLinked to original sources
PubMed1995

Health-related quality of life in patients with major depression who are treated with moclobemide.

A total of 651 depressed patients completed self-administered health-related quality-of-life (HRQOL) questionnaires during treatment with moclobemide in order to evaluate whether general and psychopathology-specific HRQOL questionnaires could detect changes in depressed patients receiving treatment. Patients were treated with moclobemide on an outpatient basis over an 8-week period; questionnaires were completed at weeks 0, 2, 4, and 8. At each assessment, patients completed one of two HRQOL questionnaires: namely, the General Health Questionnaire (GHQ), a psychopathology-specific HRQOL questionnaire, or the Short-Form 36 (SF-36), a general HRQOL instrument. Physicians were randomized to one of the two HRQOL questionnaires for all of their patients. Because the French version of the SF-36 was not available in the public domain, the patients of all Francophone physicians completed the GHQ, whereas the patients enrolled by Anglophone physicians completed either the SF-36 or the GHQ. The GHQ provides an overall score that measures the emotional dimensions of HRQOL, whereas the SF-36 provides scores in the following eight domains: physical functioning (PF), physical role functioning (PRF), emotional role functioning (ERF), social functioning (SF), bodily pain (BP), mental health (MH), vitality (VT), and general health perceptions (GHP). The GHQ and seven domains of the SF-36 detected a statistically significant linear trend (improvement) over time (p < 0.05). The change in the BP domain of the SF-36 was not statistically significant (p = 0.29).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Effects of birth asphyxia on urinary organic acid excretion.

Using capillary gas chromatography-mass spectrometry, the effects of birth asphyxia on the urinary organic acid profile of term babies was investigated. Random urine samples were collected on days 1 and 8 from 19 babies with fetal distress, 19 with moderate birth asphyxia and 12 with severe asphyxia causing encephalopathy. Controls were 27 well neonates. Statistically significant abnormalities were found only for the severely asphyxiated group: increased concentrations of lactic, pyruvic, 3-hydroxybutyric, 4-hydroxyphenyllactic and 4-hydroxy-3-methoxymandelic acids, and excretion of four abnormal metabolites, 2-hydroxybutyric, 2-oxoisocaproic, 2-hydroxyisovaleric and 2-oxo-3-methylvaleric acids. Six other babies had increased lactic acid excretion, associated in four with transient 'jitterness' or hypotonia. Organic acid studies may help to grade the severity of perinatal asphyxia in the outcome or intervention studies.

3-Hydroxybutyric Acid↗
PubMed1991

Eicosanoid production by brain tumours in vivo--evidence for intracranial compartmentation.

Brain tumours produce prostaglandins in vitro; their in vivo production has been studied by determining the levels of prostaglandin F2 alpha, prostaglandin E2, 6-ketoprostaglandin F1 alpha and thromboxane B2 in tumour cyst fluid and ventricular CSF taken from 21 patients with a variety of intracranial tumours. The levels were high in tumour cyst fluid but there was no overall increase in ventricular CSF. Hence, brain tumours do not produce a consistent pattern of abnormality of eicosanoid concentrations in the ventricular CSF that would be useful for diagnosis. If brain tumours produce excess quantities of these prostaglandins in vivo as they do in vitro, these prostaglandins may be rapidly cleared by the cerebral microvasculature unless compartmentalized within a tumour cyst.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Association of hypovolemia after subarachnoid hemorrhage with computed tomographic scan evidence of raised intracranial pressure.

Hypovolemic patients are more likely to suffer delayed cerebral ischemia and infarction after a subarachnoid hemorrhage (SAH). Prompt recognition and correction of hypovolemia may improve the outcome. We have identified computed tomographic (CT) scan findings that increase the probability of a patient presenting with hypovolemia soon after an SAH. The plasma volume (PV) of 25 patients admitted within 96 hours of an SAH was measured using radioiodinated serum albumin. The normal PVs were measured in an outpatient setting 6 months later or predicted from their total body water. Nine patients (36%) were found to be hypovolemic, defined as a fall in PV exceeding 10% of the normal PV (mean fall, 18 +/- 2%). Sixteen patients were normovolemic or hypervolemic (mean PV, +9 +/- 2%). The basal cisterns were compressed or obliterated on the CT scans of all hypovolemic patients compared with 12.5% of normovolemic patients (chi-square, 14.52; P less than 0.01). The probabilities of a patient being hypovolemic if the CT scan indicated raised intracranial pressure were high: hydrocephalus, P = 0.80; compression of the basal cisterns, P = 0.82; and compression of the basal cisterns associated with intracerebral hematoma or midline shift, P = 1.00. Patients with an SAH and radiological evidence of raised intracranial pressure should be considered at particular risk for systemic hypovolemia.

Adult↗
PubMed1991

When disaster strikes. The concerns of staff nurses.

1. This study determined how involvement with an earthquake affected patient care delivery and ascertained what nurses need to continue providing safe and efficient care in future disasters. 2. Although 60% of the staff had experienced a previous disaster, the literature described that learned coping does not automatically "transfer" to present loss experiences. 3. Providing staff with debriefing sessions and other support groups is helpful in the post-trauma period. At all levels, there is a need to communicate concerns and to be involved in disaster drills and other disaster preparedness sessions.

Adaptation, Psychological↗
PubMed1990

Combined epidural and general anesthesia for abdominal aortic surgery.

The hypothesis that combined epidural and light general anesthesia for infrarenal abdominal aortic surgery is associated with a more stable intraoperative course and less postoperative morbidity than general anesthesia alone was tested. The authors compared intraoperative hemodynamic variables and postoperative morbidity between a group with combined epidural and general anesthesia (n = 30) and a group with general anesthesia (n = 19). Patients who had combined epidural and general anesthesia were given epidural bupivacaine intraoperatively and epidural morphine postoperatively. After cross-clamping of the aorta, cardiac index and pulmonary capillary wedge pressure did not change in the group with combined epidural and general anesthesia, whereas cardiac index decreased (mean change, 0.30 L/min/m2; P = 0.0006) and pulmonary capillary wedge pressure increased (mean change, 1 mm Hg; P = 0.007) in the group with general anesthesia. After unclamping, cardiac index increased in both groups (mean change, 0.26 L/min/m2, P = 0.002, and 0.30 L/min/m2, P = 0.001, respectively). Postoperatively, the necessity for ventilatory support and the incidence of respiratory failure were lower in the combined epidural and general anesthesia group than in the general anesthesia group (P = 0.0002 and P = 0.018, respectively). In addition, vasodilator therapy was required less frequently in the group with combined epidural and general anesthesia (P = 0.002). Duration of intensive care unit stay was shorter in the combined epidural and general anesthesia group (2.7 days v 3.8 days, P = 0.003). These data indicate that for infrarenal abdominal aortic surgery, combined epidural and general anesthesia is associated with more stable intraoperative hemodynamics and significantly less postoperative morbidity than general anesthesia alone.

Adult↗
PubMed1990

Effect of hydrocephalus on prostaglandins and thromboxane B2 in ventricular cerebrospinal fluid.

The concentrations of prostaglandin F2 alpha, prostaglandin E2, 6-ketoprostaglandin F1 alpha (prostacyclin metabolite), and thromboxane B2 were assayed in ventricular cerebrospinal fluid obtained from 28 patients with hydrocephalus (17 obstructive, 11 communicating). Seven patients received dexamethasone or hydrocortisone on the day of sampling. No patient received nonsteroidal anti-inflammatory compounds for 48 hours before sampling. The median values did not differ significantly between the two types of hydrocephalus or from the concentrations in lumbar cerebrospinal fluid obtained from patients without intracranial pathology during lumbar myelography for possible lumbar disc disease. Hence, there is no evidence that eicosanoids accumulate in the ventricles in hydrocephalus, and it is unlikely that they have a significant role in its symptomatology.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Metabolism of intravenous phenylalanine by babies born before 33 weeks of gestation.

Random urine samples collected weekly from 22 infants of 25-32 weeks of gestation were analyzed by capillary gas chromatography-mass spectrometry to define the normal organic acid profile. Increased excretion of phenolic acid derivatives of phenylalanine and tyrosine was found in 21 samples from 13 babies during established parenteral nutrition. Compared with 53 samples collected during milk feeding, phenyllactic acid, 4-hydroxy-3-methoxyphenyllactic acid, and N-acetyltyrosine were excreted significantly more often and 4-hydroxyphenyllactic and 4-hydroxyphenylpyruvic acids at significantly higher concentrations. The mean daily intake of phenylalanine (197 mg/kg) was significantly higher and that of tyrosine (22 mg/kg) significantly lower during parenteral nutrition. Three cyclohexanediol isomers were identified which might have derived from phenylalanine or one of its metabolites.

Chemical Phenomena↗
PubMed1990

Urinary excretion of cyclohexanediol, a metabolite of the solvent cyclohexanone, by infants in a special care unit.

Using gas chromatography-mass spectrometry, we investigated the urinary excretion of organic acids of 278 newborn babies in a special care unit to obtain reference data and monitor metabolism. In 101 of 584 urine samples analyzed, we found isomers of cyclohexanediol. trans-1,2-Cyclohexanediol was always most abundant, with small amounts of 1,3- and 1,4-cyclohexanediol and, sometimes, traces of cis-1,2-cyclohexanediol. Glucuronide conjugates were not detected. The probable source was the solvent cyclohexanone, which was found as a contaminant of intravenous dextrose and the parenteral feeding solution, and was also leached into the infusion fluids from the administration set. We recovered 0.89 mg (range 0.74-0.98 mg, n = 5) of cyclohexanone from 150 mL of dextrose pumped through the infusion apparatus over 24 h, the normal rate for a 1-kg premature baby. Although this is well below toxic doses reported for mature animals, more data are needed for the newborn, particularly preterm infants who have a decreased capacity for glucuronide conjugation.

Cyclohexanes↗
PubMed1989

3-Methylisoxazol-5-one, an artefact from acetoacetic acid formed during urinary organic acid analysis.

During the analysis of urine for organic acids for suspected metabolic disorders by solvent extraction, derivatisation and capillary gas chromatography, unaccountably large lactic acid peaks were observed in some samples containing large amounts of acetoacetic acid. Electron impact mass spectrometry showed that this was due to two unknown compounds coeluting with lactic acid. These were found to be two trimethylsilyl derivatives of 3-methylisoxazol-5-one, produced from acetoacetic acid during oximation with hydroxylamine hydrochloride, by a cyclisation reaction. Awareness of the formation of this previously unreported artefact is important to laboratories employing a similar profiling procedure.

Acetoacetates↗
PubMed1989

Urinary excretion of 2,3-butanediol and acetoin by babies on a special care unit.

2,3-Butanediol was detected by capillary gas chromatography in 45 urine samples from 20 babies on a special care unit, 17 of whom were premature. The meso form of the diol predominated and in 21 samples was the only diastereoisomer present. Acetoin was found in 20 of the samples. It was never detected in the absence of 2,3-butanediol. 2,3-Butanediol was not detectable in more than trace amounts in urine from 66 other babies on the unit. The most likely origin of these compounds was from bacterial fermentation of pyruvate in the gut. Their presence may be explained by abnormal gut colonisation with acetoin-producing microorganisms, an abundant supply of nutrient lactose in the colon and increased intestinal permeability. It is further evidence of the magnitude of intestinal carbohydrate fermentation in preterm babies. 2,3-Butanediol could prove a useful biochemical marker for abnormal colonisation of neonates on special care units.

Acetoin↗