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Biomedical subjects

B Lacey

Publications and source records attributed to B Lacey.

13 recordsLinked to original sources
PubMed2002

Effects of maternal tobacco smoking, sleeping position, and sleep state on arousal in healthy term infants.

OBJECTIVES: To investigate whether a history of maternal tobacco smoking affected the maturation of arousal responses and whether sleeping position and infant age alters these relations. DESIGN: Healthy term infants (13 born to mothers who did not smoke and 11 to mothers who smoked during pregnancy) were studied using daytime polysomnography on three occasions: (a) two to three weeks after birth, (b) two to three months after birth, and (c) five to six months after birth. Multiple measurements of arousal threshold in response to air jet stimulation were made in both active sleep (AS) and quiet sleep (QS) when infants slept both prone and supine. RESULTS: Maternal smoking significantly elevated arousal threshold in QS when infants slept supine at 2-3 months of age (p<0.05). Infants of smoking mothers also had fewer spontaneous arousals from QS at 2-3 months in both prone (p<0.05) and supine (p<0.001) sleeping positions. In infants of non-smoking mothers, arousal thresholds were elevated in the prone position in AS at 2-3 months (p<0.01) and QS at 2-3 weeks (p<0.05) and 2-3 months (p<0.001). CONCLUSIONS: Maternal tobacco smoking significantly impairs both stimulus induced and spontaneous arousal from QS when infants sleep in the supine position, at the age when the incidence of sudden infant death syndrome is highest.

Arousal↗
PubMed2001

Monitoring clinical research: report of one hospital's experience.

Monitoring of research by research ethics boards has been recommended by various organizations that fund clinical studies and by other groups. However, little evidence has been reported on the processes, costs and outcomes of these activities, information that would be helpful to guide the boards in their current work and future policies. We report here 3 years of monitoring experience by the research ethics board of a 313-bed university-affiliated community hospital. Activities newly implemented at the beginning of the study period included the use of recruitment logs, audits of completed consent forms and interviews with research subjects. Over the study period, we monitored 33 protocols, through 188 consent form audits and interviews with 17 research subjects. In addition, 26 of 34 research investigators and collaborators responded to a survey about the monitoring. In general, the investigators were supportive of monitoring activities, but most were not willing to contribute financially. The types of monitoring we conducted are feasible and may be suitable (or could be adapted) for use in other institutions.

Clinical Protocols↗
PubMed2001

Regional changes in kynurenic acid, quinolinic acid, and glial fibrillary acidic protein concentrations in the fetal sheep brain after experimentally induced placental insufficiency.

OBJECTIVE: This study was undertaken to examine the effects of chronic embolization of the umbilical circulation during late gestation on regional concentrations of quinolinic acid and kynurenic acid (neuroactive products of tryptophan catabolism) and of the astrocyte-associated glial fibrillary acidic protein in the fetal brain. STUDY DESIGN: Pregnant ewes bearing fetuses with long-term catheter placement were treated daily with injections of either saline solution (n = 4; control group) or mucopolysaccharide microspheres (n = 5; embolized group) into the umbilical circulation through a femoral artery catheter between 120 and 140 days' gestation. The fetuses in the embolized group received sufficient microspheres each day to reduce and maintain the femoral arterial PO2 at < or =12 mm Hg. Autopsies were performed at 140 days' gestation to obtain the fetal brain for chemical analysis. RESULTS: Umbilical embolization resulted in nonacidemic hypoxia and hypoglycemia at 140 days' gestation. Quinolinic acid concentrations in the embolized group were significantly increased in the medulla, pons, midbrain, hypothalamus, and hippocampus, whereas kynurenic acid concentrations in the embolized group were reduced in the hippocampus and hypothalamus. There were significant reductions in glial fibrillary acidic protein contents in the occipitoparietal cortex, hippocampus, and pons in the embolized group. CONCLUSION: Placental compromise during late pregnancy had effects on kynurenine metabolism and astrocyte function in some regions of the fetal sheep brain. We suggest that these changes increase the vulnerability of the brain to asphyxial injury during late gestation and the perinatal period.

Animals↗
PubMed2001

The prone sleeping position impairs arousability in term infants.

OBJECTIVE: To investigate whether the prone sleeping position impaired arousal from sleep in healthy infants and whether this impairment was related to cardiorespiratory variables, temperature, or age. STUDY DESIGN: Healthy term infants (n = 24) were studied with daytime polysomnography on 3 occasions: 2 to 3 weeks after birth, 2 to 3 months after birth, and 5 to 6 months after birth. Multiple measurements of arousal threshold (cm H(2)O) in response to air-jet stimulation applied alternately to the nares were made in both active sleep and quiet sleep when infants slept both prone and supine. RESULTS: Arousal thresholds were significantly higher in both active sleep and quiet sleep when infants slept prone at 2 to 3 weeks and 2 to 3 months, but not at 5 to 6 months. These increases were independent of any sleep position-related change in either rectal or abdominal skin temperature, respiratory rate, oxygen saturation, or heart rate. CONCLUSIONS: The prone position significantly impairs arousal from both active sleep and quiet sleep in healthy term infants. This impairment in arousability occurred with no clinically significant changes in cardiorespiratory variables or body temperature. Decreased arousability from sleep in the prone position provides an important insight into its role as a risk factor for sudden infant death syndrome.

Arousal↗
PubMed1999

Distensible venous malformations of the orbit: clinical and hemodynamic features and a new technique of management.

OBJECTIVE: To investigate distensible venous malformations of the orbit (DVMO) as part of a spectrum of orbital vascular malformations, including some that involved periorbital skin, extraorbital sites (central nervous system or nasal sinuses), or combinations of these. The authors also investigated the effectiveness of a new technique of management for selected cases. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Thirty patients had distensible venous anomalies, of which four were combined distensible venous-lymphatic vascular malformations. Distensible lesions were defined as those showing clinical or radiographic expansion with Valsalva maneuver or when the head was placed in a dependent position. These lesions were then classified as superficial (anterior to the equator of the globe), deep (posterior to the globe's equator), combined (deep and superficial), or complex (with intracranial or major extraorbital involvement). INTERVENTION: Surgery was performed on 15 patients (50%), mainly for pain or for cosmetic indications. Six patients underwent this new technique, which involved intraoperative direct venography with control of outflow via pressure at the superior or inferior orbital fissure. The venous malformation was then embolized (by use of cyanoacrylate glue) and excised. RESULTS: The mean age at presentation was 28.2 years (range, 8 months to 75 years). Sixty-six percent of cases involved the left orbit. Superior and medial orbital involvement was most common. Three cases (10%) were classified as superficial, and 13 (43%) as deep. Six patients (20%) had combined superficial and deep components. Eight (27%) had major extraorbital involvement (4 intracranial, 2 facial, and 2 paranasal sinus). Direct venography demonstrated complex multichannel anomalies draining to various sites, including the face and pterygopalatine fossa, without necessarily having a direct connection to the major orbital venous circulation. CONCLUSIONS: Distensible venous malformations of the orbit are part of a spectrum of developmental venous malformations that may be localized to the orbit or involve it as part of a more extensive lesion. The authors describe their clinical and radiologic features and report a new technique of management for selected cases. This method of vascular isolation and embolization of lesions may greatly facilitate excision.

Adolescent↗
PubMed1999

Kynurenic acid in brain and cerebrospinal fluid of fetal, newborn, and adult sheep and effects of placental embolization.

Concentrations of the endogenous glutamate receptor antagonist kynurenic acid (KA) were measured in various brain regions and in cisternal cerebrospinal fluid of fetal, newborn, and adult sheep. KA concentrations were significantly higher in the fetal brain and cerebrospinal fluid at 90 and 140 d gestation compared with postnatal ages. In fetuses of 132-139 d gestation, KA concentrations in cerebrospinal fluid collected by drainage from an indwelling cisternal catheter increased significantly after infusion of the organic acid transport inhibitor probenecid (100 or 200 mg/kg, i.v.) indicating active transport of KA out of the fetal brain. In fetuses in which the umbilical circulation had been chronically restricted from 120 to 140 d gestation by partial embolization of the placenta, plasma concentrations of the KA precursor kynurenine were significantly lower than in control fetuses, and KA concentrations in the hypothalamus and hippocampus were significantly reduced; other brain regions were not affected. These results indicate that the production of KA is higher in the fetal brain compared with the newborn and adult brain. Because KA diminishes the risk of excitotoxic neuronal damage under hypoxic-ischemic conditions, the high levels of KA in the brain before birth may have a neuroprotective function. The decrease of KA concentrations in the hypothalamus and hippocampus after umbilical embolization suggests that, after chronic hypoxia in utero, these regions of the brain may become more vulnerable to subsequent episodes of acute hypoxia or ischemia encountered in late gestation or during parturition.

Animals↗
PubMed1987

Partnership in care.

The Alberta Child Health Passport was developed to provide parents and health professionals with a shared record of the child's health, growth, development, immunization and contacts with health services. A structured evaluation of the passport, and survey of the views of mothers and community nurses using it was carried out. The need for such a record was confirmed by those questioned. Responses also helped to identify sections of the booklet that are particularly useful and those which might be modified or removed. The passport is seen as having considerable advantages in improving the relationship between health professionals and clients.

Alberta↗
PubMed1977

Assessment of the agglutination test for tuberculosis.

A new whole cell agglutination test for active tuberculosis, for which encouraging results have recently been reported, has been carried out on the serum of 112 subjects. The results have been disappointing; the test had no predictive value in the diagnosis of active tuberculosis.

Agglutination Tests↗
PubMedDate not supplied

Nonthyroid causes of extraocular muscle disease.

Extraocular muscle involvement in orbital disease is most frequently seen as a feature of thyroid orbitopathy (Graves' disease). However, a wide range of other conditions may alter the size, shape, and function of these muscles, with characteristic clinical manifestations or abnormalities visible on orbital imaging. The differential diagnosis of muscle disease can be narrowed by careful analysis of clinical features and ancillary tests. Imaging facilitates recognition in many cases, but in some instances, accurate diagnosis requires biopsy. This review highlights the differential diagnoses for diseases of extraocular muscles based on the clinical and investigative records of 103 patients at our institution combined with data from the world literature. We found that the most common nonthyroid causes of muscle disease were inflammatory, vascular, and neoplastic processes (in decreasing order of frequency). Emphasis is placed on investigations that provide a logical approach to, and appropriate management of, disease of the extraocular muscles.

Amyloidosis↗