Biomedical subjects
L Morrow
Publications and source records attributed to L Morrow.
Hemodynamic effects of noninvasive bilevel positive airway pressure on patients with chronic congestive heart failure with systolic dysfunction.
BACKGROUND AND STUDY OBJECTIVES: Noninvasive positive airway pressure may play a significant role in treating patients with congestive heart failure (CHF). We tested our hypothesis that noninvasive bilevel positive airway pressure improves left ventricular performance in patients with chronic CHF secondary to severe systolic dysfunction. OBJECTIVES: To determine the cardiac performance of patients using bilevel positive airway pressure, and to describe the hemodynamic effects of bilevel positive airway pressure and its use as a therapeutic adjunct in these patients. DESIGN: Prospective, cohort, nonrandomized study. SETTING: Outpatient medicine clinic. PATIENTS: Fourteen patients (9 men and 5 women) with stable chronic CHF with left ventricular ejection fraction < or =35%; mean age was 60.6 years (range, 43 to 87 years). INTERVENTIONS: Bilevel positive airway pressure via nasal mask at an inspiratory pressure of 5 cm H(2)O and an expiratory pressure of 3 cm H(2)O on spontaneous mode at room air for 1 h. MEASUREMENTS AND RESULTS: Myocardial performance and changes were measured using clinical and echocardiographic parameters. Baseline clinical and echocardiographic parameters were compared with the same parameters after 1 h of bilevel positive airway pressure. Statistically significant (p<0.05, Wilcoxon matched pair signed-rank test) decreases were noted in these mean values: systolic BP from 136.21 to 124.14 mm Hg (p = 0.008), heart rate from 85.07 to 74.71 beats/min (p = 0.002), respiratory rate from 23.07 to 15.43 breaths/min (p = 0.001), and systemic vascular resistance from 1671. 46 to 1236.27 dyne. s. cm(3) (p = 0.001). Statistically significant increases were noted in these mean values: cardiac output from 5.09 to 6.37 L/min (p = 0.004), ejection fraction from 28.71% to 34.36% (p = 0.001), and end-diastolic volume from 224.36 to 246.21 mL (p = 0.045). CONCLUSION: Bilevel positive airway pressure has excellent potential for improving left ventricular performance of patients with chronic CHF secondary to severe systolic dysfunction.
Building-associated pulmonary disease from exposure to Stachybotrys chartarum and Aspergillus versicolor.
The authors present an outbreak of disease associated with exposure to Stachybotrys chartarum and Aspergillus species. A courthouse and two associated office buildings had generated discomfort among employees for two years since initial occupancy. Multiple interventions had been unsuccessful An initial evaluation of 14 individuals identified three with potential asthma and three with symptoms consistent with interstitial lung disease. A clinical screening protocol to identify individuals who should be removed from work identified three likely and seven possible cases of building-related asthma. Detailed environmental and engineering assessments of the building identified major problems in mechanical system design, building construction, and operational strategies leading to excess moisture and elevated relative humidities. Moisture-damaged interior surfaces in both buildings were contaminated with S. chartarum, A. versicolor, and Penicillium species. Aspergillus species, especially A. versicolor, at concentrations of 10(1) to 10(4)/m3 dominated the indoor air under normal operating conditions. Bulk samples also revealed large quantities of Stachybotrys. A questionnaire survey of the three case and two control buildings documented between three- and 15-fold increases in symptoms. A nested case-control study suggested emphysematous-like disease in individuals meeting questionnaire definitions for cases. Replication of analysis strategies used in similar previous investigations suggested an association between worsening symptoms and decreased diffusing capacity of the lung. Performance on neuropsychological measures was similar for both cases and controls, although workers with symptoms reported increased levels of current but not past psychiatric symptomatology. Chemical analyses demonstrated the presence of satratoxins G and H. Cytotoxic laboratory analyses demonstrated the presence of agents with biological effectiveness in bulk materials. No association was seen between IgE or IgG antibodies and the presence of disease. This outbreak represents a likely human response to inhaled fungal toxins in indoor environments. Moisture indoors represents a public health issue currently inadequately addressed by building, health, or housing codes.
Single-use, disposable, presterilized light-activation probe: the future?
OBJECTIVE: The purpose of this study was to compare a single-use, disposable, presterilized light activation probe with an equivalent autoclavable probe. Light output, heat generation, and depth of cure were investigated. METHOD AND MATERIALS: Ten disposable and two reusable probe tips were tested. Three maximum light output readings for each tip were recorded with a radiometer. Heat generation at the probe tip was recorded, at 30-second intervals over a five-minute period, with a thermocouple probe placed under a 3-mm-thick glass slide. After light-activated "compomer" was placed in a sectional two-piece stainless steel mold and cured, depth of cure was evaluated using the scrape technique. RESULTS: With respect to light output and depth of cure, there were no statistically significant differences between probe types, but the disposable probe generated significantly less heat. CONCLUSION: The disposable probe performed clinically as well as an autoclavable counterpart with respect to light output, heat generation, and depth of cure.
Effects of blood lead levels on cognitive function of older women.
Elevated blood lead concentrations are known to have detrimental effects on neuropsychological function in both children and occupational cohorts of men and women. Although it is generally accepted that lead exposure at low levels is more dangerous for infants and children than for adults, the issue of the lowest level of exposure at which lead causes deleterious health effects in adults is yet to be solved. There is no available data on the role of lead exposure in cognitive dysfunction in nonoccupational cohorts of older persons. In the current study, we examined the cross-sectional relationship between blood lead levels and a variety of measures of neuropsychological function in a large cohort of elderly women recruited at both urban and rural sites. This study of elderly women demonstrates that blood lead levels as low as 8 micrograms/dl were significantly associated with poorer cognitive function as measured by certain neuropsychological tests. Even a slight decrement in cognition would have a large public health impact due to the large number of elderly at risk.
Late-life spinal cord injury and aging with a long term injury: characteristics of two emerging populations.
Modern care of patients with spinal cord injury is leading to greater numbers of individuals surviving into old age and the emergence of a cohort that has sustained injury at an advanced age. The clinical characteristics of either group of patients has not been well characterized. Analyses from the Aging with a Long-Term Disability Research Program database, which is enriched by the presence of a high quality Spinal Cord Injury Service, revealed a population of 510 recently assessed individuals with a mean age of 50 years, ranging from 16 to 84 years. Twenty-three percent of the patients were at least 65 years of age. Spinal cord injuries were usually the result of automobile accidents in individuals injured younger than 50 years of age and falls in individuals injured when older than 50 years of age. Patients surviving late life injury are much more likely to have incomplete injuries predominantly affecting the cervical spine. A number of conditions were found to be more prevalent in older patients. These included carpal tunnel syndrome, chronic obstructive pulmonary disease, myocardial infarction, diabetes, kidney stones, pressure ulcers and hypertension. The development of diabetes, kidney stones and perhaps pressure ulcers was directly related to aging with SCI, but not just to aging alone. The better functional outcomes in late life spinal cord injury may be secondary to selective survival. The excess morbidity associated with late life spinal cord injury has significance for future planning of healthcare needs for the spinal cord injured patient.
Evaluation of chronic neurological sequelae after acute pesticide exposure using SPECT brain scans.
A case in which SPECT brain imaging was used in the diagnosis and treatment of chronic effects from acute acetylcholinesterase inhibitor poisoning is presented. The patient was exposed to an insecticide mixture containing phosphorothiate, pyrethrin, piperonyl butoxide, and petroleum distillates, which produced symptoms consistent with acute acetylcholinesterase inhibitor poisoning as well as an upper respiratory tract irritant. Delayed sequelae of gross neurologic symptoms followed, that is, coarse tremor, intermittent hemiballistic movements of the right arm and leg, flaccid muscular tone, fasciculations of muscle groups, muscle cramps, and sensory disturbances. A brain single-photon emission computerized tomography (SPECT) scan was performed 34 mo postexposure, revealing significantly decreased blood flow to the left temporal lobe and to the right and left basal ganglia. The patient's paresthesias were treated with phenytoin, which resulted in worsening of her movement disorder. A trial of amantadine and selegiline (Deprenyl) resulted in a dramatic reduction in dysfunctional movements and ataxia. Post amantadine and selegiline therapy, brain SPECT images revealed significantly improved blood flow with minimally decreased blood flow to the right and left basal ganglia. The use of SPECT scan techniques helped to elucidate objective chronic central nervous system effects subsequent to an acute insecticide exposure and also assisted in the evaluation of the effectiveness of therapeutic intervention.
Three-dimensional brain metabolic imaging in patients with toxic encephalopathy.
Thirty-three workers, ages 24 to 63, developed clinical toxic encephalopathy after exposure to neurotoxins and were studied by SPECT brain scans. Five were exposed to pesticides, 13 were acutely exposed to mixtures of solvents, 8 were chronically exposed to mixtures of hazardous wastes that contained organic solvents, 2 were acutely exposed to phosgene and other toxins, and 5 had exposures to hydrogen sulfide. Twenty-nine had neuropsychological testing and all had a medical history and physical. Of the workers who had a clinical diagnosis of toxic encephalopathy, 31 (93.9%) had abnormal SPECT brain scans with the most frequent areas of abnormality being temporal lobes (67.7%), frontal lobes (61.3%), basal ganglia (45.2%), thalamus (29.0%), parietal lobes (12.9%), motorstrip (9.68%), cerebral hemisphere (6.45%), occipital lobes (3.23%), and caudate nucleus (3.23%). Twenty-three out of 29 (79.3%) neuropsychological evaluations were abnormal. Other modalities when performed included the following percentages of abnormals: NCV, 33.3%; CPT sensory nerve testing, 91.3%; vestibular function testing, 71.4%; olfactory testing, 89.2%; sleep EEG analysis, 85.7%; EEG, 8.33%; CT, 7.14%; and MRI brain scans, 28.6%. The complex of symptoms seen in toxic encephalopathy implies dysfunction involving several CNS regions. This series of patients adds to the previous experience of brain metabolic imaging and demonstrates that certain areas of the brain are typically affected despite differences in toxin structure, that these lesions can be globally defined by SPECT/PET brain scans, that these lesion correlate well with clinical and neuropsychological testing, and that such testing is a useful adjunct to previous methods. EEG and structural brain imaging such as CT and MRI are observed to have poor sensitivity in this type of patient. Additional metabolic imaging studies need to be done to explore dose, time, and specific toxin effects as well as mechanisms of toxicity and olfactory migration.
Mechanism of connective tissue techniques. I. The effect of dye concentration and staining time on anionic dye procedures.
Anionic dye connective tissue procedures were performed by staining for 5 min and 24 h with (a) 0.00018 M and 0.0018 M solutions of 28 dyes, and 0.018 M solutions of 21 dyes in saturated picric acid (SPA), and (b) 0.0018 M and 0.018 M solutions of 20 dyes in 1% (w/v) phosphomolybdic acid (PMA). The staining obtained with dyes in SPA was classified as selective (no cytoplasmic staining), moderately selective (traces of cytoplasmic staining) and non-selective (all other staining patterns). The staining of collagen and cytoplasm with dyes in PMA was separately classified on a scale of 1-5 (1 = no staining, 5 = maximum staining). The selectivity of the staining obtained with SPA with solutions of dyes at concentrations of 0.00018 M and 0.0018 M, and both staining times, was correlated (p < 0.001) with an empirical sulphonic acid constant (SAC) defined as the (number of dye sulphonic acid groups/dye molecular weight) x 10(3). Correlation with molecular weight was poor and was significant only when staining was performed with 0.00018 M dye solutions for 24 h. The dyes were divisible into three groups: group 1 (selectivity independent, or almost independent of staining time), group 2 (selective to moderately selective when staining was performed for 5 min), and group 3 (non-selective). The SAC of the group 1 dyes differed significantly from those of the group 2 and 3 dyes. Selectivity was essentially lost at dye concentrations of 0.018 M. The staining with acidic dyes (no amines or substituted amines) in PMA differed significantly (p < 0.001) from that obtained with amphoteric dyes (containing basic substituents).(ABSTRACT TRUNCATED AT 250 WORDS)
When one body can save another.
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'Repetition strain injury': an Australian epidemic of upper limb pain.
An analysis is provided of a recent Australian epidemic of an upper limb regional pain syndrome known as 'repetition strain injury' (RSI). 'RSI' was originally attributed to occupational over-use of the upper limb and biomechanical and ergonomic solutions were sought. More sceptical commentators argued that 'RSI' was an epidemic form of hysteria. More recently, a consensus has emerged that the epidemic is attributable to a combination of factors: a change in the perception of endemic symptoms of upper limb pain; the iatrogenic effects of the term 'RSI' and the methods used to manage it; and complications of the medico-legal process in which many sufferers became entangled.
Luteinizing-hormone-releasing hormone agonist treatment in patients with previously failed folliculogenesis during in vitro fertilization therapy.
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Contributions of in vitro fertilization to knowledge of the reproductive endocrinology of the menstrual cycle.
The administration of ovarian stimulants to endocrine-normal women in IVF programmes gives the clinical endocrinologist an opportunity to modify natural folliculogenesis. Use of antioestrogens and/or gonadotrophins at the correct time has demonstrated that follicular atresia can be prevented and that multiple pregnancy-potent haploid ova can be obtained. Scrutiny of spontaneous menstrual cycles in patients who show unsatisfactory IVF responses has identified two new syndromes, premature follicle selection and occult ovarian failure, in these patients. The incidence of these disorders in fertile women is still unclear. Early results suggest that endocrine manipulations may overcome premature follicle selection and induce codominant folliculogenesis. Inhibin is a recently characterized ovarian protein which is increased in peripheral blood during IVF treatment. Results from IVF cycles suggest that plasma inhibin may be a new index of follicular function. Other potential indices of ovarian function, such as the luteal protein relaxin, may also develop from the application of basic research to IVF and advance knowledge of the human ovarian and menstrual cycles.
Low level lead exposure and neuropsychological functioning in blue collar males.
To examine the interrelationships between normal aging, occupational lead exposure, and cognitive functioning, a comprehensive battery of neuropsychological tests was administered to 288 randomly-selected lead-exposed workers and 181 demographically-similar nonexposed controls. Contrary to previous reports, those workers with current blood-lead levels in the low to moderate range (less than 50 micrograms/dl) were found to perform as well as controls on measures of learning, memory, attention, visuospatial ability, and general intelligence. They differed from controls only on one measure of psychomotor speed and manual dexterity, the Grooved Pegboard Test, and these between-group differences were restricted to the older lead workers. It is likely that these results are secondary to lead-mediated neuromuscular damage. There is little support for the view that older adults with current blood lead levels in the low to moderate range are at risk for developing significant CNS dysfunction, even though they may have had a past history of excessively high blood lead levels.
Visuospatial impairment in Parkinson's disease. Role of perceptual and motor factors.
We investigated the role of perceptual and motor factors in visuospatial impairment in 30 patients with Parkinson's disease (PD) and 30 matched controls. All subjects were administered visuospatial tests, which included "visuoperceptual" tasks, requiring minimal motor responses, and "visuomotor" tasks. The performance of patients with PD was considerably impaired on several tasks from both groups, and this impairment was not related to depression or intellectual impairment. Patients in stage 3 of the disease tended to show the greatest impairment. Those in stage 1 (unilateral symptoms), however, tended to show more impairment than those in stage 2.
Visuoperceptual and visuomotor abilities and locus of lesion.
Possible differential effects of laterality and caudality of cerebral lesions on simple visuoperceptual and visuomotor skills were examined. As expected, the right hemisphere lesion group was significantly more impaired than the left hemisphere lesion group. The effects of the caudality of lesion, however, yielded interesting results. While the right posterior group was worse than the right anterior lesion group, as expected, the left posterior lesion group was better than the left anterior lesion group. Our findings points to a possibility that the left hemisphere, especially the anterior region, might not be as silent in processing simple visual stimuli as has been accepted.
Classroom-based approaches to developing social competence among hearing-impaired youth.
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