Biomedical subjects

C M Ryan

Publications and source records attributed to C M Ryan.

At least 73 records · Page 4Linked to original sources

PubMed1993

Gut macromolecular permeability in pancreatitis correlates with severity of disease in rats.

BACKGROUND: Increased intestinal macromolecular permeability could allow absorption of substances from the bowel into the systemic circulation and contribute to multiple organ system failure. METHODS: Mild, intermediate, and severe grades of pancreatitis were induced in rats using intravenous caerulein and intraductal glycodeoxycholic acid. [14C]polyethylene glycol (molecular weight, 3350 daltons; 1.1 microCi/142 mg) was instilled into the distal duodenum. At 24 hours, the animals were killed, ascitic fluid was collected for trypsinogen activation peptide measurement, and pancreatic specimens were collected and scored for based on the degree of necrosis, inflammation, and hemorrhage. RESULTS: Gut permeability to polyethylene glycol 3350 (PEG 3350) was increased in animals with early experimental pancreatitis (5.4% +/- 1.2%, n = 20) when compared with control animals (1.8% +/- 0.2%; n = 6) (P = 0.0005). Furthermore, intestinal macromolecular permeability to PEG 3350 correlated with severity of disease as predicted by the method of induction of pancreatitis (P = 0.0003), the histological findings (P = 0.0002), and total ascitic trypsinogen activation peptides content (P = 0.029). CONCLUSIONS: Increased gut permeability in experimental pancreatitis can be correlated with pancreatitis severity.

Animals↗

PubMed1993

Acute adrenal insufficiency in the burn intensive care unit.

Acute adrenal insufficiency may underlie a confusing, stormy, intensive care unit course after a burn. The aetiology is most likely to be adrenal haemorrhage despite the absence of a coagulopathy. This report describes two patients who were diagnosed antemortem and successfully treated with replacement therapy. The aetiology, presentation, diagnosis and treatment of acute adrenal insufficiency in the intensive care unit is reviewed.

Acute Disease↗

PubMed1993

Effects of insulin-dependent diabetes on learning and memory efficiency in adults.

Previous work with elderly adults with maturity-onset non-insulin-dependent diabetes has demonstrated the presence of significant learning and memory deficits which are correlated with the degree of chronic hyperglycemia. This study was conducted to examine learning and memory processes in a group of 82 younger adults (mean age = 33.4 years) with a long history (mean duration = 26.2 years) of childhood-onset insulin-dependent diabetes. Contrary to expectation, diabetic subjects performed as well as a group of 82 age- and SES-matched nondiabetic control subjects on all measures of learning and memory. On the other hand, they performed significantly worse on measures of psychomotor efficiency, with degree of chronic hyperglycemia being the best predictor of psychomotor slowing. These findings, together with earlier studies of elderly diabetic patients, suggest that specific neural systems within the aging brain may be differentially sensitive to the "toxic" effects of chronic hyperglycemia.

Adult↗

PubMed1993

Flavobacterial sepsis in massively burned pediatric patients.

An experience with wound sepsis due to Flavobacterium meningosepticum in two pediatric burn patients is described. This organism, which is typically found in water and soil, generally has low pathogenicity but may become clinically important in immunocompromised hosts. It is typically resistant to antibiotics prescribed for infections caused by aerobic, gram-negative bacteria. When flavobacteria are suspected as pathogens, initial therapy should begin with ciprofloxacin, trimethoprim-sulfamethoxazole, or clindamycin.

Adolescent↗

PubMed1993

Isolation and long-term culture of human hepatocytes.

Pressure-controlled perfusion of specimens of surgical hepatic resection produced improved yields of human hepatocytes for studies of long-term cultures. The effect of an extracellular matrix configuration on albumin secretion was evaluated by culture on a single layer of collagen or between double layers of collagen gel with Dulbecco's modified Eagle and Williams E media. Hepatocytes from 12 patients were maintained for more than 30 days, and in five of 12 experiments cells were cultured beyond 2 months. In the double gels the cells demonstrated typical polygonal liver cell morphology and higher albumin secretion (p < 0.01) up to 65 days; in contrast, in the single gels cells spread horizontally, and albumin secretion declined rapidly within 3 weeks. A comparison of media formulations showed that maximum albumin secretion occurred 5 days later but was maintained significantly longer with Dulbecco's medium (p < 0.01). The simple addition of a second layer of gelled collagen forming a collagen sandwich significantly stabilizes and supports the long-term culture of human hepatocytes.

Albumins↗

PubMed1992

A participatory workplace health and safety training program for ethylene oxide.

The Occupational Safety and Health Administration (OSHA) has regulated ethylene oxide (EtO) on the basis of its acute toxicity and its potential carcinogenic and reproductive effects since 1971. OSHA's 1984 EtO standard and its 1988 revisions focused new attention on health and safety training and other preventive measures. An EtO health and safety training program for hospital sterilization workers was developed by the staff of an independent occupational and environmental health clinic. Participatory and empowerment training methods were central to the approach. Also included were hands-on, demonstration, interactive presentation, and other methods. An EtO Health and Safety Training Manual was developed based on the training experiences. This paper presents the challenges, benefits, and limitations of incorporating participatory and empowerment approaches in the design, implementation, and evaluation of EtO health and safety training.

Central Supply, Hospital↗

PubMed1992

Separation and quantitation of polyethylene glycols 400 and 3350 from human urine by high-performance liquid chromatography.

Polyethylene glycol 3350 (PEG 3350) is useful as an orally administered probe to measure in vivo intestinal permeability to macromolecules. Previous methods to detect polyethylene glycol (PEG) excreted in the urine have been hampered by inherent inaccuracies associated with liquid-liquid extraction and turbidimetric analysis. For accurate quantitation by previous methods, radioactive labels were required. This paper describes a method to separate and quantitate PEG 3350 and PEG 400 in human urine that is independent of radioactive labels and is accurate in clinical practice. The method uses sized regenerated cellulose membranes and mixed ion-exchange resin for sample preparation and high-performance liquid chromatography with refractive index detection for analysis. The 24-h excretion for normal individuals after an oral dose of 40 g of PEG 3350 and 5 g of PEG 400 was 0.12 +/- 0.04% of the original dose of PEG 3350 and 26.3 +/- 5.1% of the original dose of PEG 400.

Adult↗

PubMed1992

Dysfunctional buildings or dysfunctional people: an examination of the sick building syndrome and allied disorders.

As Bauer et al. (1992) have indicated, psychological variables may play a prominent role in workplace-related disorders, like sick building syndrome. To place their work in a broader context, a spectrum of workplace disorders is described that encompasses sick building syndrome, building-related illness, neurotoxic disorders, and mass psychogenic illness. For each disorder, the authors identify both the building- (or exposure-) related variables and the psychological variables believed to trigger or maintain the unique pattern of somatic and neuropsychiatric symptoms. Strategies to aid in diagnostically differentiating the four syndromes are also discussed.

Air Pollution, Indoor↗

PubMed1992

Increased gut permeability early after burns correlates with the extent of burn injury.

OBJECTIVE: To determine if increased gut permeability within 48 hrs after burn injury correlates with the extent of injury, before sepsis and pulmonary disorders have complicated the clinical course. DESIGN: Nonrandomized, controlled study. PATIENTS: Consecutive patients admitted with burn injuries on > 20% of body surface area. INTERVENTIONS: Intestinal absorption and renal excretion of polyethylene glycol 3350 was used as the macromolecule to determine gut permeability; polyethylene glycol 400 intestinal absorption was used as an internal control for abnormal motility and malabsorption. Polyethylene glycol 3350 (40 g) and polyethylene glycol 400 (5 g) were administered enterally. MEASUREMENTS AND MAIN RESULTS: Gut permeability was significantly increased early after the injury. The patients excreted 0.56 +/- 0.34% (n = 11) of polyethylene glycol 3350, compared with the amount (0.12 +/- 0.04%) (p < .05) previously reported in normal volunteers. There was no significant difference in the excretion of polyethylene glycol 400 in the patients (27.0 +/- 4.6%, n = 11) vs. the normal volunteers previously reported (26.3 +/- 5.1%, n = 12), suggesting normal intestinal motility and absorption. The percentage of excretion of polyethylene glycol 3350 correlated with the percentage body surface burned; patients with smaller injuries excreted 0.32 +/- 0.17% (n = 6), which was greater than normal and less than those values from patients with larger injuries, 0.84 +/- 0.25% (n = 5) (p < .001 by Turkey test). CONCLUSIONS: Using our newly developed method to separate and quantify polyethylene glycols in urine, gut permeability was found to be increased early after burn injury, which confirms a previous study using lactulose as the permeability probe. Furthermore, this increased gut permeability to polyethylene glycol 3350 correlated with the extent of the burn injury.

Adult↗

PubMed1992

Psychomotor slowing is associated with distal symmetrical polyneuropathy in adults with diabetes mellitus.

To test the hypothesis that diabetes mellitus is associated with cognitive dysfunction, a battery of neuropsychological tests was administered to 75 diabetic adults and an equal number of demographically similar nondiabetic control subjects. Compared with control subjects, diabetic subjects performed significantly more poorly on measures of psychomotor efficiency and spatial information processing. In contrast, no between-group differences appeared on measures of verbal intelligence, learning, memory, problem solving, or simple motor speed. Results from multiple regression analyses showed that clinically significant distal symmetrical polyneuropathy was strongly associated with psychomotor slowing, whereas, glycosylated hemoglobin values were weakly associated with both psychomotor slowing and spatial processing. No other biomedical variables predicted cognitive test performance. These neurobehavioral data are consistent with the hypothesis that a "central neuropathy" may be associated, at least in part, with chronic hyperglycemia.

Adult↗

PubMed1991

Learning and memory function in men with untreated blood pressure elevation.

Learning and memory processes were compared in 20 men with untreated blood pressure elevation and 20 normotensive control subjects matched for age, education, and average alcohol consumption. Subjects were identified from a larger sample of 469 factory workers who had participated in an epidemiologic investigation. Three measures (e.g., Symbol-Digit Learning Test [Ryan & Butters, 1980] and Visual Reproductions-Immediate and Delayed Recall [Wechsler, 1945] ) from a previously administered test battery were chosen for comparison on the basis of statistical power calculations. Results indicate that relative to normotensive control subjects, men with elevated blood pressure performed more poorly on all three tests. These results are independent of other known influences on neuropsychological performance and are likely a consequence of elevated blood pressure.

Adult↗

PubMed1991

Neuropsychological correlates of hypertension: review and methodologic considerations.

Essential hypertension is a chronic disorder having many potential physical and behavioral sequelae. This article evaluates the impact of hypertension on neuropsychological test performance. First, cross-sectional and longitudinal studies that examine the neuropsychological correlates of hypertension are reviewed. In general, hypertensives are found to perform more poorly than normotensives, particularly on tests of memory, attention, and abstract reasoning, and less consistently on tests of perception, constructional ability, mental flexibility, and psychomotor speed. Next, the influence of variables that may moderate relationships between hypertension and neuropsychological performance--such as age, education, and medication usage--are examined. Finally, potential mechanisms, both physiological and psychological, underlying associations between hypertension and neuropsychological performance are discussed.

Brain↗

PubMed1991

Risk factors associated with persistence of neuropsychological deficits in persons with organic solvent exposure.

This study examined neuropsychological prognosis following organic solvent exposure. Twenty-seven persons with evidence of "mild toxic encephalopathy" were evaluated on two separate occasions with a standard neuropsychological test battery and the Minnesota Multiphasic Personality Inventory. Ratings by experienced clinicians revealed that 50% of exposed persons had improved neuropsychological performance at the second evaluation. The other 50% were rated as having no change or a decline in neuropsychological tests scores. While the majority of persons in the good-outcome group were working at the time of the follow-up evaluation, none of the persons in the poor-outcome group was actively employed. Persons rated as having shown no improvement were significantly more likely to have had a peak exposure--an episode in which they were briefly exposed to a larger than normal amount of solvent. In addition, persons in the poor outcome group reported higher levels of psychological distress, both initially and at the follow-up evaluation. Results from this study suggest that the presence of certain risk factors, namely a peak exposure and psychological distress, may be particularly detrimental for long-term neuropsychological outcome in persons with a history of organic solvent exposure.

Adult↗

PubMed1990

Mild hypoglycemia associated with deterioration of mental efficiency in children with insulin-dependent diabetes mellitus.

To assess the effects of mild hypoglycemia on cognitive functioning in diabetic children, we used an insulin glucose clamp technique to induce and maintain a hypoglycemic state. Eleven patients, 11 to 18 years of age, completed a series of cognitive tests during a baseline euglycemic state (100 mg/dl (5.5 mmol/L] and repeated those measures at the beginning and end of a hypoglycemic plateau (55 to 65 mg/dl (3.1 to 3.6 mmol/L], and again at restoration of euglycemia. At plasma glucose levels of 60 to 65 mg/dl (3.3 to 3.6 mmol/L), a significant decline in mental efficiency was found. This was most apparent on measures of mental "flexibility" (Trial Making Test) and on measures that required planning and decision making, attention to detail, and rapid responding. Moreover, complete recovery of cognitive function was not contemporaneous with restoration of euglycemia, particularly on those tests requiring rapid responding and decision making (choice reaction time). Not all subjects showed evidence of cognitive impairment during hypoglycemia. The very high degree of intersubject variability suggests that, in addition to plasma glucose values, unknown physiologic variables are responsible for triggering cognitive impairments in school-aged youngsters with diabetes during an episode of mild hypoglycemia.

Adolescent↗

PubMed1990

Alterations in cognitive and psychological functioning after organic solvent exposure.

Exposure to organic solvents has been linked repeatedly to alterations in both personality and cognitive functioning. To assess the nature and extent of these changes more thoroughly, 32 workers with a history of exposure to mixtures of organic solvents and 32 age- and education-matched blue-collar workers with no history of exposure were assessed with a comprehensive battery of neuropsychological tests. Although both groups were comparable on measures of general intelligence, significant differences were found in virtually all other cognitive domains tested (Learning and Memory, Visuospatial, Attention and Mental Flexibility, Psychomotor Speed). In addition, Minnesota Multiphasic Personality Inventories of exposed workers indicated clinically significant levels of depression, anxiety, somatic concerns and disturbances in thinking. The reported psychological distress was unrelated to degree of cognitive deficit. Finally, several exposure-related variables were associated with poorer performance on tests of memory and visuospatial ability.

Adult↗

PubMed1990

Memory disturbances following chronic, low-level carbon monoxide exposure.

Neuropsychiatric sequelae are a common feature of acute carbon-monoxide (CO) poisoning-particularly when the patient has experienced an episode of CO-induced unconsciousness. In this case report, we present neuropsychological test data demonstrating the presence of mild cognitive impairments following a chronic (3-year) history of low-level CO exposure that never produced loss of consciousness. Deficits were limited to concentration and memory; performance on measures of general intelligence, visuospatial functioning, and speed and dexterity were well within the normal range.

Journal Article↗

PubMed1989

Effectiveness of triazolam, diazepam, and placebo as preanesthetic medications.

Eighty-three ASA Physical Status 1-2 patients were orally premedicated with triazolam (0.125, 0.25, or 0.5 mg), diazepam (5, 10, or 15 mg), or placebo to evaluate the effectiveness of these drugs and doses in reducing preoperative anxiety, providing sedation, and producing amnesia. The drug treatments were administered in a randomized, double-blind manner. The results obtained with each drug (dose) group were compared against those of the placebo group as a control. Changes in anxiety at 60 min after drug administration were evaluated: 1) by a trained anesthesia nurse clinician using an analog scale, 2) by the patient using the same analog scale, and 3) by the patient with the Multiple Affect Adjective Check List (MAACL). Changes in sedation at 60 min were also evaluated by the patient and nurse clinician using an analog scale. Amnesia was assessed by postoperative recall of picture cards shown to the patient 1 h after receiving preanesthetic medication. There were no significant differences between any drug (dose) and placebo for changes in patient-evaluated anxiety or sedation on the analog scale. With the other measures of anxiety, only triazolam (0.5 mg) reduced anxiety more than did placebo on both the patient (MAACL) and the nurse (analog) scales. With the nurse (analog) measure of sedation, only the highest doses of triazolam and diazepam were more sedating than placebo. Triazolam (0.5 mg) was the only drug dose that produced significant amnesia. The authors conclude that drug effects on anxiety, sedation, or amnesia that are statistically significant versus placebo effect are seen at only the highest doses of triazolam (0.5 mg) and diazepam (15 mg).

Adult↗

PubMed1989

A distinct pattern of personality disturbance following exposure to mixtures of organic solvents.

To assess systematically the pattern of psychologic distress in chemically exposed workers complaining of personality changes, we administered the Minnesota Multiphasic Personality Inventory to 22 men with a history of exposure to mixtures of organic solvents. Results indicated clinically significant profile elevations in more than 90% of the exposed workers. Moreover, a consistent response profile was noted, indicating a high rate of somatic disturbances, anxiety, depression, social isolation, and fear of losing control. In addition, those workers with the longest exposure duration had the highest elevations on the scale measuring disturbances of thinking, social alienation, poor concentration, and anxiety. Comparisons between these subjects and a group of former prisoners of war with posttraumatic stress disorder revealed strikingly similar clinical profiles. We present a case history that illustrates the nature of this psychologic disturbance.

Adult↗