Angiography and magnetic resonance imaging of aortic dissection

This review article describes and illustrates the role of angiography and magnetic resonance imaging in the evaluation of aortic dissection. Clinical findings, complications, classification, and treatment of dissection are reviewed as well.     

The use of thromboprophylaxis in total hip replacement surgery: are the attitudes of orthopaedic surgeons changing?

We conducted a survey of all 926 active members of the British Orthopaedic Association using a postal questionnaire to find out their current attitude to thromboprophylaxis in total hip replacement surgery. Previous surveys have been performed, and with all the recent literature on the subject we wanted to see if the attitude of British orthopaedic surgeons has changed. There were 676 replies, a response rate of 73%. Fifty-five replies were excluded, those from surgeons who had retired from practice or whose practice did not include total hip replacement surgery. Of the remaining 621 surgeons, 466 (75%) use some method of thromboprophylaxis, with 367 (59%) routinely using prophylactic pharmacological agents and 99 (16%) using mechanical methods of thromboprophylaxis. Twenty-five per cent (155) of surgeons used no routine method of thromboprophylaxis. Eight-six per cent (534) of surgeons used a pharmacological method of prophylaxis in those patients thought to have a high risk of developing a deep vein thrombosis (DVT) (eg previous DVT, cardiovascular disease, obesity). Thirty-two different methods of thromboprophylaxis were used. Low molecular weight heparin is now being used by 19% of surgeons routinely and by 25% of surgeons in high risk cases, whereas 3 years ago it was not used at all. Our survey shows that although there is still a great reluctance for British orthopaedic surgeons to use pharmacological agents routinely in thromboprophylaxis. Amongst those that do, low molecular weight heparin is being increasingly used. More surgeons may want to use low molecular weight heparin routinely, but in some hospitals it is not currently available.     

The epidemiology of severe injuries to children in northern Manhattan: methods and incidence rates

The epidemiology of injury incidence in inner-city children has not previously been described. This study presents the methods used and the incidence rates found for severe injury (causing hospitalisation or death) in a population of 89,000 children under age 17 years in northern Manhattan, a largely poor area of New York City. The average annual incidence rate (measured from 1983 to 1987) for severe injuries to children under 17 was 846/100,000 a year. The vast majority (79%) were classified as unintentional. Nine per cent were due to assault, 3% were self-inflicted and in an additional 9% the intention was unclear. Classified by cause, the highest incidence (per 100,000/year) was found for falls (218), vehicle-related (141, primarily pedestrian), ingestion (119) and burns (110). Guns caused 3% of the injuries (27). The death rate from injury was 18.7/100,000, 36% of which was due to homicide. In an additional 28%, intentional injury was suspected. The suicide rate was 0.4/100,000. The leading causes of injury death included guns and burns (both 2.7/100,000). Compared with childhood injury rates in predominantly rural and suburban populations, the rates reported here for northern Manhattan are higher for overall injury incidence (fatal and non-fatal) and for homicide, but lower for injury mortality not due to homicide.     

Complex Genetic Disease: Can Genetic Strategies in Alzheimer's Disease and New Genetic Mechanisms Be Applied to Epilepsy?

Summary: Strategies used in molecular genetics have changed modern neurology. The gene or genes responsible for several major neurologic diseases have now been identified using "reverse" or positional genetics. Unexpected new genetic mechanisms have been discovered in human neurologic diseases, including (a) identical mutations of the prion protein gene in Creutzfeldt-Jakob disease and fatal familial insomnia with the phenotypic expression directed by an accompanying polymorphism; (b) stable duplications of chromosome 17 in Charcot-Marie-Tooth disease (type 1 A) that involve many genes, only one of which appears to cause neuropathy; and (c) highly variable, dynamic mutations in myotonic dystrophy, fragile X syndrome, and Kennedy's syndrome that modulate variable expressivity in multiple tissues. There is growing recognition that neurologic diseases are often complex genetic diseases with multifactorial rather than simple modes of inheritance. For example, genetic association/linkage strategies have interacted with biochemistry and immunopathology studies to produce new insights into the disease mechanism of late-onset Alzheimer's disease. The role of apolipoprotein E in late-onset Alzheimer's disease is an example of how new analytical techniques of genetic disease can be applied to dissect multiple genes. Similar research strategies are suggested for the study of epilepsy as a complex disease.     

Alcohol and Platelet Function

Epidemiological studies have shown that moderate consumption of alcoholic beverages is inversely related to the incidence of the complications of coronary artery disease. The protective effect of ethanol may be partially attributable to an inhibitory effect of ethanol on platelets. This article summarizes the experimental observations that ethanol inhibits platelet responses to specific physiological agonists. In alcoholics, various platelet defects have been observed, but these may be influenced by metabolic factors rather than the presence of ethanol alone. The acute effects of ethanol on platelet functions both in vivo and ex vivo will be reviewed. Evidence will be presented demonstrating that ethanol added acutely in vitro inhibits phospholipase A₂ in stimulated platelets. The interaction of ethanol with other signal transduction pathways will also be discussed.