The effect of selective brain cooling on intracerebral temperature during craniotomy.

In this study we investigated the effect of topical application of cool irrigation fluid on brain tissue temperature during craniotomy. Eight patients were given a standard general anaesthetic for craniotomy. Distal oesophageal and nasopharyngeal temperatures were measured continuously and systemic normothermia was maintained. A sterile needle temperature probe was inserted 18 mm into the cerebrum to measure brain temperature. Brain temperatures were recorded for five minutes while the brain was irrigated with 1000 ml of normal saline at a temperature of 30 degrees C. Measurement continued until the brain temperature returned to baseline. The mean maximum decrease in cerebralparenchymal temperaturefollowing irrigation was 1.6 +/- 0.5 degrees C (P<0.01). The average time to return to baseline temperature after cessation of irrigation was 5.3 +/- 1.5 minutes. Cooling the brain has a marked protective effect after brain injury, but systemic hypothermia can produce significant harmful effects. This study demonstrates that the use of cool irrigation fluid during neurosurgery is a simple and effective method of cooling the brain whilst minimizing the use of systemic hypothermia.

Combating the 'safe' cigarette: ethical, public health issues and regulatory proposals.

Regulatory authorities have advised smokers who would not or could not quit smoking to switch to lower tar cigarettes. Smoking such cigarettes was seen as a means of reducing the harm caused by smoking, but not as offering a 'safe' smoking option. Correspondingly manufacturers have been required to place tar and nicotine information on packet labels and/or advertisements. This paper explores the possibility that the conventional format for conveying tar and nicotine information could be responsible for the belief, held by a significant proportion of smokers, that some brands of lower tar cigarettes are absolutely 'safe'. To deal with this situation it is suggested that changes should be made to health warnings, and tar and nicotine communications. Proposed changes to the latter are evaluated in terms of their ethical and public health implications. The authors conclude that brand specific warnings and a classification of cigarettes as either 'Very Dangerous' or 'Dangerous', is best suited to reconciling consumer needs for information with the public health objectives of reducing the harm caused by smoking.

Acute myelogenous leukemia (FAB AML-M1) in the setting of HIV infection and G-CSF therapy: a case report and review of the literature.

Although hematologic dysplasia is common in HIV disease, evolution to AML is unusual. We report a case of AML in a patient with stage-C3 AIDS who had been previously treated with granulocyte colony-stimulating factor (G-CSF). This 41-year-old black man presented with pancytopenia (Hg 8.6 g/dl, Hct 24.3%, platelets 16,000/mm3, WBC 0.6 x 10(3)/mm3) and hemoptysis. His peripheral smear manifested 19% blasts. His bone marrow biopsy was hypocellular (20%) with greater than 90% blasts, which were positive for myeloperoxidase and Sudan black B. The blasts were negative for nonspecific esterase. Immunophenotypic analysis by flow cytometry showed the majority of cells to be of myeloid lineage, expressing CD13, and CD45 at low intensity. In addition, there was aberrant expression of CD2 and no expression of CD14 or CD4. The diagnosis of AML-FAB-M1 was made. The patient refused chemotherapy. Of the rare cases of AML in HIV patients previously reported in the literature, the majority were of the monocytic or myelomonocytic subtype. This case is of special interest because of prior G-CSF therapy. In this setting, the relationship between HIV, G-CSF, and subsequent AML is controversial.

Subjects and accomplices: regulation and the ethics of cigarette advertising.

In debates on the regulation of cigarette advertising, opposition to regulation is based on a perceived threat to individual autonomy and choice. Advocates of regulation have sought to combat such arguments by focusing on the unique characteristics of tobacco: the absence of a "safe" level of consumption; that the habit is often acquired by children or young persons; that smokers are unaware of the extent of the risks involved; and that smoking is "addictive." The authors discuss the implications of these characteristics for regulation and the difficulties with such arguments. The focus on characteristics of the product means that little attention is given to the implications of the content and techniques of advertising. The dominant forms of cigarette advertising involve the communication of little product information and the use of persuasive mechanisms of which the consumer is either unaware or not fully aware. The authors explore the implications of such advertising strategies for regulation and public policy.

Primary meningeal glioma.

A 59 yr old man presented with headaches and was shown to have a posterior fossa tumor arising from the inferior surface of the tentorium cerebelli. At operation the tumor was discrete from the cerebellum and was thought to be a meningioma. Pathological examination showed the tumor had features similar to those of a meningioma. It consisted of interlacing bundles of spindle cells with a considerable amount of connective tissue. Some mitoses were present. The tumor cells, however, showed abundant staining for glial fibrillary acidic protein indicating their astrocytic nature. The tumor was diagnosed as astrocytoma Grade 2. The tumor 'recurred' 4 mths later and a second surgical removal was attempted. Pathological examination showed features similar to those in the first operative specimen but this time invasion of the cerebellum was present. Deep x-ray treatment (D.X.R.T.) did not alter the tumor growth which proved fatal 7 mths after presentation. The differential diagnosis of an apparently meningeal-based tumor includes the rare entity of primary meningeal glioma. The case is presented as an example of this rare entity which both clinically and pathologically may be mistaken for a meningioma. The prognosis of intracranial solitary primary leptomeningeal gliomas is variable with recurrence and survival being months to years.

Ethical and practical implications of the human genome initiative for family medicine.

Major advances in predictive genetic testing resulting from the Human Genome Initiative could change significantly the routine practice of family medicine. Family physicians should be aware that increased genetic information may affect patients' abilities to acquire and maintain insurance and employment and that interested parties will have incentives to seek this information. The social consequences of genetic information, as well as increased health promotion efforts, may raise problems of informed consent and confidentiality. In addition to their ethical implications, these developments will also affect the practice of family physicians in practical ways such as record keeping. We discuss cases that illustrate the potential impact of these emerging technologies on the practice of family medicine.

Insurance and genetic testing: where are we now?

Basic research will spur development of genetic tests that are capable of presymptomatic prediction of disease, disability, and premature death in presently asymptomatic individuals. Concerns have been expressed about potential harms related to the use of genetic test results, especially loss of confidentiality, eugenics, and discrimination. Existing laws and administrative policies may not be sufficient to assure that genetic information is used fairly. To provide factual information and conceptual principles upon which sound social policy can be based, the Human Genome Initiative established an Ethical, Legal, and Social Issues Program. Among the first areas to be identified as a priority for study was insurance. This paper provides a review of life, health, and disability insurance systems, including basic principles, risk classification, and market and regulatory issues, and examines the potential impact of genetic information on the insurance industry.

Thoracic intramedullary haematoma as a complication of warfarin: case report and literature review.

Spontaneous intraspinal haematomas due to anticoagulants are uncommon, and usually extradural or subdural. Intramedullary haematomas are particularly rare, and only two case reports were found in the literature. We report a case of a thoracic intramedullary haemorrhage in a 61 year old man who had been commenced on warfarin 1 month previously, following aortic valve replacement. The literature is reviewed and reversal of warfarin effects, imaging and recommendations for treatment are discussed.

Hypotensive effect of mannitol administered rapidly.

Mannitol is an osmotic diuretic commonly used to reduce intracranial pressure. While various side-effects, including hyperosmolar states, precipitate reduction in intracranial pressure, rebound phenomenon and hypervolaemia have been described, hypotension due to rapid administration has not been widely recognised.

Laboratory model ecosystem studies of the degradation and fate of radiolabeled tri-, tetra-, and pentachlorobiphenyl compared with DDE.

Radiolabeled tri-, tetra-, and pentachlorobiphenyls (PCB) and DDE were studied in a laboratory model ecosystem for degradation pathways, and biomagnification in alga, snail, mosquito, and fish. Trichlorobiphenyl was degraded in all the organisms of the model ecosystem much more rapidly than tetrachloro- and pentachlorobiphenyl. Pentachlorobiphenyl was approximately as persistent as DDE. There was a linear relationship between lipid/water partition and ecological magnification and between water solubility and ecological magnification. No evidence of conversion of DDE to PCB was detected.