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Biomedical subjects

J M Ryan

Publications and source records attributed to J M Ryan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Analysis of several phenolic compounds with potential antioxidant properties in grape extracts and wines by high-performance liquid chromatography-photodiode array detection without sample preparation.

A RP-HPLC method that allows the separation of several types of phenolic compounds present in grapes and wines by direct injection of samples, using a binary gradient with solvents free of salts and photodiode array detection is described. Results show that more than 15 different phenolic molecules with antioxidant properties (flavan-3-ols, anthocyanins, cinnamic acid derivatives, flavonol derivatives and trans-resveratrol) may be separated in a single run by direct injection of red wine. The method is also valuable for the analysis of these compounds in white wine and in skins, seeds and pulp extracts of red and white grapes.

Antioxidants↗
PubMed2000

White coat effect of alcohol.

Numerous studies have shown a relationship between alcohol intake and elevated clinic blood pressures (BP). However, there have been few studies on the relationship between alcohol consumption and 24-h ambulatory BP monitoring. This study aimed to determine the relationship between alcohol intake, clinic BP, and 24-h ambulatory BP recordings to determine to what extent a white coat effect may contribute to the relationship between alcohol consumption and BP. Clinical BP and 24-h ambulatory BP were measured in 121 male volunteers aged 50.6 +/- 9.8 years (range, 30-70 years) who consumed between 0 and 2050 g of alcohol per week (mean, 394 +/- 342 g; median, 385 g/week). Supine clinical systolic BP (SBP) was significantly related to alcohol intake (beta = 0.242; P = .007). Alcohol consumption was not related to 24-h mean SBP or diastolic BP (DBP), daytime SBP or DBP, or nighttime SBP or DBP (daytime SBP: beta = 0.02, P = .802). Alcohol intake was significantly related to the difference between clinic SBP and mean daytime SBP (beta = 0.260, P = .004). Twenty-four-hour mean heart rate (HR), daytime mean and nighttime mean HR were strongly associated with alcohol intake (24-h HR: beta = 0.455, P < .001). These results suggest that the association between alcohol consumption and elevated BP is contributed to by a significant white coat effect and that excessive alcohol consumption may be a significant factor in explaining differences between clinic and ambulatory BP measurements.

Adult↗
PubMed2000

Conversion of indwelling chest port catheters to tunneled central venous catheters.

PURPOSE: To determine the safety and efficacy of the conversion of subcutaneous chest wall infusion ports to tunneled central venous catheters. MATERIALS AND METHODS: During a period of 34 months, 67 patients were referred for conversion of indwelling subcutaneous chest wall ports to tunneled central venous catheters as part of a bone marrow transplant protocol. Six patients were deemed unacceptable for conversion and the remaining 61 underwent successful conversion. All patients had functioning surgically placed single-lumen (n = 50) or double-lumen (n = 11) chest ports, which were removed to maintain the original venous access sites for placement of a tunneled central venous catheter, incorporating the chest wall pocket for tunneling, in 46 patients (75%). A new tunnel was created in the other 15 patients. There were no immediate complications and all patients were followed until catheter removal or patient demise with the catheter in place. RESULTS: 57 of 61 (93%) catheters were used without evidence of infection for 23-164 days (mean, 57 d) after placement. Two (3%) were removed (both at 26 days) because of persistent neutropenic fever without physical signs or laboratory evidence of catheter infection, and two (3%) were removed (at 11 and 77 days) because of proven catheter infection, yielding an overall infection rate of 1.2 per 1,000 catheter days. Two catheters required exchange and two required stripping because of decreased function, resulting in an overall catheter-related complication rate of 2.4 per 1,000 catheter days. CONCLUSIONS: Indwelling subcutaneous chest wall infusion ports can be safely converted to tunneled central venous catheters, even in an immunocompromised patient population, with a low risk of complications such as infection.

Adult↗
PubMed2000

Pharmacologic approach to aggression in neuropsychiatric disorders.

Aggressive behavior has been associated with numerous neurologic conditions including traumatic brain injury, mental retardation, developmental disorders, Huntington disease, and several dementias. Preclinical and human studies suggest that dysfunction of neural systems involving the brainstem, hypothalamus, amygdala, or prefrontal cortex can give rise to aggression. Several neurochemicals are felt to be relevant to modulation of aggression, including serotonin, dopamine, norepinephrine, GABA, acetylcholine, and androgens. Pharmacologic intervention studies have targeted these systems but have been limited by inconsistent definitions of aggression and a relative paucity of controlled trials. This article briefly reviews studies of neural systems and medication trials relevant to aggression and propose a clinical approach to treatment of patients manifesting aggressive behavior.

Aggression↗
PubMed2000

Creating a DIN to tackle drug-related deaths in the community.

Brighton and Hove has one of the highest rates of drug-related deaths in the UK. The deceased commonly have had contact with a number of organizations isolated from each other. The aim of this study was to explore aspects of drug addiction in Brighton as the first stage in the creation of a local Drug addiction Intervention Network (DIN) and to make recommendations about improving the effectiveness of medical contacts so that modifiable risk factors could be addressed appropriately and consistently. The coroner's records of the drug-related deaths in 1998 for Brighton and Hove were cross-referenced with computerized records of the Accident & Emergency department of the local hospital and the police station. Of the 36 drug misusers who died during the year, most were male, mean age 34 years. Alcohol was a common comorbid finding. Seventy-eight per cent were known to the A&E department and 62% had been arrested locally during 1997 or 1998. Such retrospective data can only give limited information. We, therefore, performed a prospective survey. It was carried out by the forensic medical examiner (FME) in 1997-1998, interviewing 41 arrestees to give a profile of the criminally involved drug misusers. With the information obtained, the A&E doctors and FMEs were able to review the medical advice given and establish a protocol for the transfer of severely intoxicated arrestees.

Journal Article↗
PubMed2000

Brain attack!--How good is the early management of subarachnoid haemorrhage in accident and emergency departments? South Thames A&E Specialty Sub Committee Audit Group.

OBJECTIVES: The aim of this study was to assess the characteristics and audit the management of patients for whom a diagnosis of subarachnoid haemorrhage was made and who were admitted to a neurosurgical centre from an accident and emergency (A&E) department. The objective was to use the results to make recommendations for improving care in this group of patients. METHODS: Four neurosurgical centres in the South Thames Region provided lists of patients admitted with a diagnosis of subarachnoid haemorrhage during 1997. The medical records and computed tomography of 162 patient episodes from 20 A&E departments were reviewed. The speed of presentation, the provisional diagnosis and the referral patterns were examined. Patient records were audited to investigate what proportion were treated according to established guidelines while in the A&E departments. RESULTS: 63.7% of patients presented to A&E within six hours of ictus and 81.1% within three days. Some 49.2% of patients were seen by a doctor within 30 minutes and 74.7% within one hour. Computed tomography was performed on 18.8% within two hours and only 66.3% within six hours of arrival at the A&E department. Eighteen per cent were treated with nimodipine, 26% with intravenous fluids and 32% were given analgesia before leaving the department. Delays occurred in obtaining computed tomography. CONCLUSIONS: The management of patients who present to A&E departments with subarachnoid haemorrhage is suboptimal. Improved awareness of the disorder, management by senior A&E staff and clear care pathways could help with management.

Emergency Service, Hospital↗
PubMed2000

Drug related deaths in the community: a preventive role for accident and emergency departments?

Reducing drug related deaths has been identified as a priority by the British government. This study examined the link between drug related deaths in the community and prior contact with local accident and emergency (A&E) services. Most drug related deaths were found among male opioid users in their early 30s who had previously attended the local A&E department. It is suggested that A&E departments have a vital part to play, not only in the acute management but also in the prevention of drug related deaths in the community. Models for primary prevention, liaison and ongoing referral are discussed.

Adult↗
PubMed1999

Abdominal injuries and sport.

Serious abdominal injuries resulting from sport are rare. The potential for misdiagnosis is significant and the consequences may be serious. Patients with abdominal pain should be taken very seriously and investigated with appropriate diagnostic equipment. Sporting bodies have a responsibility to address safety within a particular sport and to change the rules where necessary as injury patterns are identified.

Abdominal Injuries↗
PubMed1999

Incorporation of an (125)I-labeled hexa-iodinated diglyceride analog into low-density lipoprotein and high specific uptake by cells of cervical carcinoma cell lines.

The feasibility of using low-density lipoprotein (LDL) to deliver cytotoxic drugs to tumor cells has been explored since the 1980s, when cells of a number of cancer cell lines were found to have higher LDL receptor activity than normal cells. Such differential uptake between tumor and normal cells may provide a unique opportunity to use LDL as a tumor-specific carrier of radiopharmaceuticals for the clinical management of cancer. In this study, an (125)I-labeled hexa-iodinated diglyceride analog, 1, 3-dihydroxypropan-2-one 1,3-diiopanoate (DPIP), was synthesized and incorporated into LDL using a fusion technique. It was found that approximately 500 [(125)I] DPIP molecules were incorporated into each LDL particle. Cells of three human cervical tumor cell lines, HeLa, SiHa and C-33A, were used to examine the cellular uptake of the [(125)I]DPIP-LDL conjugate. It was shown that the [(125)I]DPIP-LDL conjugate was specifically bound to and taken up by cervical tumor cells through an LDL receptor-mediated endocytosis pathway. The results suggest that LDL may be a selective carrier for delivering hydrophobic radiopharmaceuticals to cancer cells and particularly for the diagnosis of cervical tumors.

Binding Sites↗
PubMed1998

Radiographic detection of achalasia: diagnostic accuracy of videofluoroscopy.

AIMS: To retrospectively evaluate the accuracy of videofluoroscopy in the diagnosis of achalasia. MATERIALS AND METHODS: Videofluoroscopic studies of the oesophagus of 53 patients (25 males, 28 females; mean age, 49 years) with manometrically revealed diagnosis of achalasia were retrospectively evaluated. The videofluoroscopic examinations had been carried out with one swallow of low-density barium suspension in the erect and up to three swallows in the prone oblique position. Videofluoroscopically, a diagnosis of achalasia was made in 31 of the patients (58%) with manometrically proven achalasia, of whom only nine had oesophageal dilatation. Non-specific oesophageal motor abnormalities were diagnosed radiographically in 18 patients (34%) and a normal motility in four patients (8%). CONCLUSION: Videofluoroscopy is a valuable and sensitive technique for the detection of disordered oesophageal motility in achalasia.

Barium Sulfate↗
PubMed1998

Implementation of a two-tier trauma response.

OBJECTIVE: To apply a triage tool to patients on their arrival in the emergency department and determine the efficacy and safety of a two-tier trauma response. DESIGN: Descriptive prospective audit. SETTING: Principal urban referral hospital that provides a major trauma service. MATERIALS AND METHODS: The triage tool designated a major trauma or stable trauma response. A major trauma designation mobilised a multidisciplinary team and a stable trauma designation an expedited evaluation by emergency department staff. Chi-square test and Mann-Whitney U test were used to compare major and stable trauma designations. Triage accuracy was evaluated using outcome variables. MAIN RESULTS: 78% of 58 major trauma responses and 30% of 180 stable trauma responses were admitted. The median injury severity score (and interquartile range) of admitted patients was 9.0 (5.0-19.5) for major responses and 5.0 (2.0-9.0) for stable responses. The triage tool had a sensitivity of 65%, specificity of 87%, accuracy (appropriate triage rate) of 82%, undertriage rate of 8% and overtriage rate of 10%. CONCLUSION: The triage tool adequately distinguished between patients with and without major trauma. Undertriaged patients had timely and appropriate referral for definitive surgical care and had no adverse outcomes.

Adolescent↗
PubMed1998

COMPTEL measurements of the omnidirectional high-energy neutron flux in near-earth orbit.

On four occasions, twice in 1991 (near solar maximum) and twice in 1994 (near solar minimum), one COMPTEL D1 detector module was used as an omnidirectional detector to measure the high-energy (> 12.8 MeV) neutron flux near an altitude of 450 km. The D1 modules are cylindrical, with radius 13.8 cm and depth 8 cm, and are filled with liquid scintillator (NE213A). The combined flux measurements can be fit reasonably well by a product of the Mt. Washington neutron monitor rate, a linear function in the spacecraft geocenter zenith angle, and an exponential function of the vertical geomagnetic cutoff rigidity in which the coefficient of the rigidity is a linear function of the neutron monitor rate. When pointed at the nadir, the flux is consistent with that expected from the atmospheric neutron albedo alone. When pointed at the zenith the flux is reduced by a factor of about 0.54. Thus the production of secondary neutrons in the massive (16000 kg) Compton Gamma-Ray Observatory spacecraft is negligible. Rather, the mass of the spacecraft provides shielding from the earth albedo.

Astronomy↗