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Biomedical subjects

J Ryan

Publications and source records attributed to J Ryan.

At least 91 records · Page 5Linked to original sources

What goes wrong at a disaster or major incident?

From a receiving hospital's perspective a major incident is 'an accident about to happen'. The potential for chaos is present at every phase. This short paper describes in a chronological fashion the common traps and pitfalls and how to avoid them.

Crisis Intervention↗

Straddle injuries--is current practice safe?

Genital injuries may be markers of sexual abuse and child protection issues should be considered when case present. This study evaluates the quality of history taking and the physical examination of children who present with straddle injuries to an accident and emergency department. A retrospective analysis of the accident and emergency case notes of children who presented over a 12-month period with straddle injuries was undertaken. A scoring system of risk factors was devised to help identify children at risk of sexual abuse and applied to the case notes. The results showed that the documentation of injuries was inadequate in the majority of cases, increasing the risk that cases of sexual abuse may be missed. Core questions which aid in the selection of children who require further evaluation have previously been identified. Utilizing the information from our findings we have devised a protocol for the assessment of children with straddle injuries which includes an action plan for the management of such cases.

Child↗

A controlled trial of an educational program to prevent low back injuries.

BACKGROUND: Low back injuries are common and costly, accounting for 15 to 25 percent of injuries covered by workers' compensation and 30 to 40 percent of the payments made under that program. The high costs of injury, the lack of effective treatment. and the evidence that there are behavioral risk factors have led to widespread use of employee education programs that teach safe lifting and handling. The effectiveness of those programs, however, has received little rigorous evaluation. METHODS: We evaluated an educational program designed to prevent low back injury in a randomized, controlled trial involving about 4000 postal workers. The program, similar to that in wide use in so-called back schools, was taught by experienced physical therapists. Work units of workers and supervisors were trained in a two-session back school (three hours of training), followed by three to four reinforcement sessions over the succeeding few years. Injured subjects (from both the intervention and the control groups) were randomized a second time to receive either training or no training after their return to work. RESULTS: Physical therapists trained 2534 postal workers and 134 supervisors. Over 5.5 years of follow-up, 360 workers reported low back injuries, for a rate of 21.2 injuries per 1000 worker-years of risk. The median time off from work per injury was 14 days (range, 0 to 1717); the median cost was $204 (range, zero to $190,380). After their return to work, 75 workers were injured again. Our comparison of the intervention and control groups found that the education program did not reduce the rate of low back injury, the median cost per injury, the time off from work per injury, the rate of related musculoskeletal injuries, or the rate of repeated injury after return to work; only the subjects' knowledge of safe behavior was increased by the training. CONCLUSIONS: A large-scale, randomized, controlled trial of an educational program to prevent work-associated low back injury found no long-term benefits associated with training.

Adolescent↗

In differentiated CD4+ T cells, interleukin 4 production is cytokine-autonomous, whereas interferon gamma production is cytokine-dependent.

CD4+ T cells from T cell receptor transgenic mice that have been vigorously primed to be interleukin (IL)-4 producers (T(H2) cells) are capable of producing IL-4 even if restimulated in the absence of IL-4 and in the presence of IL-12. T cells vigorously primed in the absence of IL-4 (T(H1) cells) fail to produce IL-4 even if restimulated under conditions that would cause a naive T cell to produce IL-4. In contrast, interferon gamma (IFN-gamma) production is highly cytokine-regulated. T cells primed in the presence of IL-4 develop into IFN-gamma producers if IFN-gamma is included in the priming culture and if the cells are challenged in the presence of IL-12, presumably reflecting the role of IFN-gamma in inducing responsiveness to IL-12. Cells primed in the absence of IL-4 become highly responsive to IL-12 if IFN-gamma is included in the priming culture, and these cells are excellent IFN-gamma producers upon challenge; IL-12 considerably enhances their production of IFN-gamma. If cells are primed in the absence of IL-4 and IFN-gamma, they show very weak responsiveness to IL-12 as determined by STAT-4 activation. However, these cells acquire IL-12 responsiveness if cultured with IFN-gamma for a period as short as 4 hr. Thereafter, they produce large amounts of IFN-gamma upon challenge with antigen in the presence of IL-12. These results indicate that in primed CD4+ T cells, IL-4 production is largely cytokine-autonomous, whereas IFN-gamma production is highly cytokine-regulated.

Animals↗

L-arginine prevents cyclosporin A-induced pulmonary vascular dysfunction.

BACKGROUND: Cyclosporin A is known to alter endothelium-dependent responses to different agonists. Few data are available concerning the effect of cyclosporin A on the pulmonary vascular bed. METHODS: The endothelium-dependent responses to acetylcholine (20 micrograms), bradykinin (5 micrograms), and substance P (5 micrograms) were investigated in a dog model of left lung autoperfusion at constant flow. RESULTS: The vasodilator response to bradykinin and substance P was significantly decreased with cyclosporin A (20 mg) administration. The average decreases in pulmonary arterial pressure with bradykinin were 5.4 +/- 1.5 mm Hg and 2.4 +/- 0.4 mm Hg before and after cyclosporin A administration, respectively (p = 0.04). The average decreases in pulmonary arterial pressure with substance P were 4.4 +/- 1.0 mm Hg and 1.8 +/- 0.5 mm Hg before and after cyclosporin A administration, respectively (p = 0.04). The responses to acetylcholine and the endothelium-independent relaxing agent nitroglycerin were not significantly affected by cyclosporin A. The effects of cyclosporin A on endothelium-dependent responses to bradykinin and substance P were overcome by the administration of L-arginine (200 mg/kg intravenously). The decreased response to bradykinin and substance P after cyclosporin A administration was not significantly affected by indomethacin, a cyclooxygenase inhibitor. The pulmonary angiotensin-converting enzyme activity was also measured using [3H]benzoyl-phenylalanyl-glycyl-proline, an inactive angiotensin-converting enzyme substrate. There was an average [3H]benzoyl-phenylalanyl-glycyl-proline hydrolysis of 54% +/- 2% and 55% +/- 2% before and after cyclosporin A administration, respectively (not significant). CONCLUSIONS: The present study suggests that cyclosporin A selectively decreases endothelium-dependent responses to bradykinin and substance P without affecting the cyclic guanosine monophosphate-dependent pathway in the canine pulmonary vascular bed. The decreased endothelium-dependent responses to bradykinin and substance P are not related to increased angiotensin-converting enzyme activity. The toxic effect of cyclosporin A on endothelium-dependent responses is reversible by the administration of L-arginine, a source of substrate for nitric oxide.

Acetylcholine↗

Bilateral locked posterior shoulder dislocation in a footballer.

Posterior dislocation of the shoulder is an uncommon injury, accounting for between 2% and 4% of all shoulder dislocations. It occurs most frequently in patients following convulsions or direct anterior force to the shoulder. It is a particularly uncommon injury in sport. This paper reports an unusual case of bilateal locked posteriorly dislocated shoulders in a previously healthy young man who fell while playing football.

Adult↗

How good are doctors at estimating children's weight?

OBJECTIVE: (1) To see whether children are weighted before drugs are prescribed in an accident and emergency (A&E) department; (2) to assess how safe it is for doctors to guess children's weight if they prescribe "by eye". METHODS: An audit of 100 sets of notes was performed to see if children were weighed before drugs were prescribed. A&E senior house officers were asked to estimate the weight of 75 children aged 12 years and under. RESULTS: Children were weighed before prescribing in only two out of 100 cases. The mean difference between the actual and estimated weights was -0.21 (not significantly different from zero: P = 0.40); 95% of the estimates were within two standard deviations of the mean difference. The percentage difference between the actual and estimated weight varied between overestimates of 300% and underestimates of nearly 100%. CONCLUSIONS: The average guess of doctors as a group was approximately correct. However, there was a wide range of estimates for individuals. If the child's weight is guessed, the doctor could risk under- or overprescribing analgesia, sedation, or intravenous fluids. Given the wide range of estimates, actual weights are required for accurate prescribing. Prescribing on an age basis may be acceptable for drugs such as paracetamol or amoxycillin, but it is imperative to prescribe on a mg/kg basis for opiates, sedatives, and intravenous fluids because of the large variation in weight that can occur for a single age.

Body Weight↗

Lipopolysaccharide induces cell shrinkage in rabbit ventricular cardiac myocytes.

The effects of 10 ng/ml of lipopolysaccharide (LPS) on cell volume were examined in rabbit left ventricular myocytes. The myocytes were isolated with depyrogenated digestive enzymes (< 0.7 ng/ml of LPS) to minimize tolerance. Myocyte cross-sectional area (CSA) did not change after 1 h of LPS. However after 8 h, the CSA decreased to 0.93 +/- 0.01 (SE) of the baseline CSA (time = 0) in 19 LPS-exposed myocytes compared with 1.00 +/- 0.01 in 13 control myocytes (P = 0.0015). LPS-induced cell shrinkage was completely blocked by coincubation with 1 mM N-monomethyl-L-arginine, indicating a nitric oxide-mediated mechanism. Cardiac guanosine 3',5'-cyclic monophosphate (cGMP) did not change after 1 h but increased 6 h after LPS (548 +/- 31 vs. 312 +/- 20 fmol/mg protein in control cells; P < 0.05). After 8 h, bumetanide (10 microM for 30 min), a Na+/K+/2Cl- cotransport inhibitor, decreased the CSA in 15 control myocytes to 0.92 +/- 0.02 of the baseline CSA. However, in 19 myocytes with a CSA of 0.93 +/- 0.01 of baseline after 8 h of LPS, the addition of bumetanide caused no additional cell shrinkage. We conclude that low levels of LPS increase cardiac cGMP to inhibit Na+/K+/2Cl- cotransport, causing significant cell shrinkage in cardiac myocytes.

Animals↗

Alcohol consumption and blood pressure in recently hospitalised patients.

One-thousand-four-hundred-and-fifty-three patients admitted to a teaching hospital, haemodynamically stable and not severely ill nor in significant pain, were interviewed within 48 h of admission and demographic data and a detailed drinking history were obtained. Supine blood pressures (BP) were recorded on the day following admission. The mean age of the population was 60.5 +/- 19.9 years (range 16-99 years) and the mean reported alcohol consumption was 67.8 +/- 273 g/week (range 0-6125 g/ week). Thirty-six percent of patients were currently receiving antihypertensive drug therapy. On multivariant analysis, reported alcohol intake was not significantly related to systolic BP (beta = 0.000, p = 0.902) or diastolic BP (beta = 0.028, p = 0.281). Age (beta = 0.331, p = 0.0001) and body weight (beta = 0.121, p = 0.0002) were significant independent predictors of systolic BP, and body weight was a significant independent predictor of diastolic blood pressure (beta = 0.207, p < 0.0001). A relationship between alcohol consumption and blood pressure was not apparent in this population of patients following admission to hospital. A positive association between alcohol consumption and blood pressure may not be a universal finding and may be contributed to by a "white coat" effect.

Adolescent↗

Enhanced ABC costing for hospitals: directed expense costing.

Space limitations do not allow a complete discussion of all the topics and many of the obvious questions that the preceding brief introduction to directed expense costing probably raised in the reader's mind. These include how errors in accounting practices like posting expenses to the wrong period are handled; and how the system automatically adjusts costs for expenses benefiting several periods but posted to the acquisition month. As was mentioned above, underlying this overtly simple costing method are a number of sophisticated and sometimes complex processes that are hidden from the normal user and designed to automatically protect the integrity and accuracy of the costing process. From a user's viewpoint, the system is straightforward, understandable, and easy to use and audit. From a software development perspective, it is not quite that effortless. By using a system that is understood by all users at all levels, these users can now communicate with each other in a new and effective way. This new communication channel only occurs after each user is satisfied as to the overall costing quality achieved by the process. However, not all managers or physicians are always happy that the institution is using this "understandable" cost accounting system. During one of the weekly meetings of a hospital's administrative council, complaints from several powerful department heads concerning the impact that the use of cost data was having on them were brought up for discussion. In defending the continued use of the system, one vice president stated to the group that cost accounting does not get any easier than this, or any less expensive, or any more accurate. The directed expense process works and works very well. Our department heads and physicians will have to come to grips with the accountably it provides us to assess their value to the hospital.

Accounting↗

Benzodiazepine prescribing in a Sydney teaching hospital.

OBJECTIVES: To determine the pattern of benzodiazepine prescribing in hospital and at discharge in relation to prior benzodiazepine therapy. DESIGN: Patient interview within 48 hours of admission to determine benzodiazepine, alcohol and other psychotropic drug use before admission and review of medical records after discharge to document drugs prescribed in hospital and at discharge. SETTING: Tertiary teaching hospital, January to August 1995. RESULTS: 1453 patients (mean age, 60 [SD, 19] years; 52.7% female) were interviewed; 277 patients (19.1%) were taking benzodiazepines regularly (one or more doses per week) before admission. Of these, 28.5% did not have benzodiazepine therapy continued while in hospital and 63.9% did not receive benzodiazepines at the time of discharge. Of the remaining 1176 patients (those not previously taking benzodiazepines), 277 (23.6%) were prescribed them for the first time in hospital and 5.3% received benzodiazepines at the time of discharge. Older age, female sex, marital status (single, divorced or widowed) and the use of antidepressants and Schedule 8 narcotic analgesics were all statistically significant predictors of benzodiazepine use before admission, but alcohol consumption was not. CONCLUSIONS: A substantial number of patients do not have their benzodiazepine therapy continued in hospital and at the time of discharge, and are thus at risk of developing benzodiazepine withdrawal syndromes, including delirium. A small but clinically significant number of patients who do not usually take benzodiazepines receive them at the time of discharge and may be at risk of becoming long term users.

Anti-Anxiety Agents↗

Photodynamic therapy (PDT) of the ciliary body with silicon naphthalocyanine (SINc) in rabbits.

BACKGROUND AND OBJECTIVE: To investigate silicone naphthalocyanine (SINc; 0.5 mg/kg) for photodynamic therapy (PDT) of the ciliary body in pigmented rabbits. STUDY DESIGN/MATERIALS AND METHODS: SINc was dissolved in canola oil by heating, emulsified with Tween-80, and given by ear vein. Pharmacokinetics were studied in frozen sections by fluorescence microscopy using a CCD camera-based, low light detection system with digital image processing at 1 hr and 24 hr (12 rabbits, 24 eyes total). A Ti:Sapphire laser delivered light at 770 nm by contact fiberoptic (1,000 microns; 80 mW/cm2;20,40 and 80 J/cm2). Controls (5 rabbits), received laser light at 770 nm without SINc. For comparison, eyes received continuous wave Nd:YAG laser by fiberoptic contact (0.8-1.2 J). RESULTS: Localization studies showed intravascular distribution shifting to a ciliary body distribution at 24 hr. PDT at 1 hr and 24 hr postinjection showed a more selective destruction of the ciliary body at 24 hr. Ciliary processes treated at 24 hr showed infarction and marked edema with sparing of iris. Tissue thermal damage was minimal in PDT controls. Eyes treated with the Nd:YAG laser exhibited full-thickness thermal necrosis of iris, ciliary processes, and a fibrinous iridocyclitis. In contrast, eyes treated by PDT were quiet with thrombosis of superficial blood vessels. CONCLUSION: Tissue photon penetration is good at 770 nm and thermal effects from the exciting laser alone were minimal. The ciliary processes of pigmented rabbits exhibit a selective retention of SINc and on that basis can be selectively destroyed with a minimum on thermal damage to nontarget tissues.

Aluminum Oxide↗

Smooth muscle-derived nitric oxide is elevated in isolated forearm veins in human alcoholic cirrhosis.

1. Cirrhosis is often complicated by disturbances in the systemic circulation. We have previously demonstrated decreased vascular responses to vasoconstrictors in forearm resistance arteries in subjects with alcoholic cirrhosis. In the current study we investigate the role of the potent endogenous vasodilator nitric oxide in the peripheral circulation of these patients. 2. Ten patients with alcoholic cirrhosis (Pugh grade A) and 10 age-matched control subjects were studied. The effect of blockade of nitric oxide synthesis was studied both in vivo in forearm resistance arteries using forearm venous occlusion plethysmography and in vitro in veins isolated from the forearm. The role of endothelium-derived nitric oxide was studied in vivo using the endothelium-dependent vasodilator acetylcholine. 3. Mean arterial pressure and forearm basal flow in vivo were similar in the two groups. The constrictor response (percentage decrease in forearm blood flow) to noradrenaline (100 ng/min) was 26% smaller in patients with cirrhosis (31.65 +/- 2.64%) than in control subjects (42.75 +/- 3.87%, P = 0.037). Constrictor responses to the nitric oxide synthase inhibitor NG-monomethyl-L-arginine were not different in the two groups. Dilator responses to acetylcholine were significantly attenuated in cirrhotic patients compared with control subjects. 4. To investigate the role of smooth muscle-derived nitric oxide in vitro, all veins were stripped of their endothelium. Responses to noradrenaline were significantly diminished in veins isolated from patients with cirrhosis compared with control subjects. Incubation with the nitric oxide synthase inhibitor N omega-nitro-L-arginine had no effect on responses to noradrenaline in veins from control subjects but significantly enhanced the maximal response to noradrenaline by 23.95% (range 3.77-100%, P = 0.043) in veins from patients with cirrhosis. 5. Responses to noradrenaline were attenuated in vivo in forearm resistance arteries in patients with alcoholic cirrhosis. This impairment was also apparent in forearm isolated veins, stripped of the endothelium. Our data exclude a major role for endothelium-derived nitric oxide but highlight a possible role for smooth muscle-derived nitric oxide.

Acetylcholine↗

Cigarette smoking at hire as a predictor of employment outcome.

We have reported that cigarette smoking at the time of hire is associated with elevated rates of accidents, injuries, absence, discipline, and firing among US postal workers. We followed this cohort of 2537 for a second year to assess whether these associations would change with time in a workplace with active smoking cessation programs. Smokers' elevated risks for accidents, injuries, and discipline decreased after the first year. Risk for involuntary turnover was slightly higher in the 2-year analysis. The elevation in the rate of absence for smokers remained comparable in both periods. Although it is possible that the decline in the relative risk of accidents, injuries, and discipline may reflect changes in smoking status, we were unable to obtain follow-up data on smoking status to test this hypothesis.

Absenteeism↗

Validation of the combined olfactory test.

A new test of olfactory function, the combined olfactory test, has been designed to assess odours easily recognizable by the test population. The test consists of an odour recognition test of nine odours, where an odour in a bottle is chosen from a list of four possible odours in a forced choice manner. This is followed by a threshold test using a series of three-fold dilutions of 1-butanol. The mean of the two scores is the combined olfactory score. The test was subjected to a validation study. It was performed on 133 participants with a normal sense of smell and a normal rhinological examination and on 94 participants who said that they did not have a sense of smell. There was a highly significant difference between the combined olfactory score in the normal and 'anosmic' groups (P < 0.001). This significant difference was the same between the two groups for the threshold and odour recognition arms of the test. There was a highly significant difference (P < 0.001) between the two subgroups of 'completely anosmic' and 'almost anosmic' participants, indicating that the test could grade the degree of olfactory dysfunction.

Adult↗