The effect of hyperbaric oxygen on irradiated oral tissues: transmucosal oxygen tension measurements

PURPOSE

This study measured the effect of hyperbaric oxygen (HBO) treatment on transmucosal oxygen tension in irradiated human oral mucosa.

PATIENTS AND METHODS

Ten patients received 30 dives of HBO as part of their treatment for mandibular osteoradionecrosis. A noninvasive, nonheated oxygen electrode was used to measure the tissue surface transmucosal oxygen tension directly on the attached gingiva. Measurements were done before, during, and after HBO treatment. The normal level of gingival surface transmucosal oxygen tension was measured in five healthy volunteers.

RESULTS

During HBO treatment, the transmucosal oxygen tension increased significantly after five dives of HBO (P < .05). After 30 dives, the increases were from a mean of 50% to a mean of 86% of the transmucosal oxygen tension of normal healthy gingiva.

CONCLUSION

An increase in the transmucosal oxygen tension is based on neo-angiogenesis. Patients with subischemic tissues, such as the study population with postirradiation mucosal and osseous necrosis, therefore may benefit from treatment with HBO.

Principles and applications of flow injection analysis in biosensors

In practical applications biosensors are often forced to operate under less than optimal conditions. Because of their construction, and the physical processes and chemical reactions involved in their operation, compromise conditions are frequently required to synchronize all events taking place. Therefore, and in order to implement functions such as periodic calibration, conditioning and possible regeneration of the biosensor, and, very importantly, to yield the freedom to select the optimum detection means, it is advantageous to use these devices in a flow-through mode, particularly by employing the flow injection (FI) approach. The capacity of FI, as offering itself as a complementary facility to augment the performance of biosensors, and in many cases as an attractive alternative, is demonstrated by reference to selected examples, comprising assays based on enzymatic procedures with optical and thermal detection procedures, and via description of a recently introduced technique for immunoassays, termed flow injection renewable surface immunoassays, which promises to entail powerful potentials and to yield compatible or better economy of operation than existing approaches.

Determination of minute amounts of ATP by flow injection analysis using enzyme amplification reactions and fluorescence detection

A flow-injection system for assay of trace levels of ATP is described that incorporates a small column reactor containing co-immobilized hexokinase, pyruvate kinase and glucose-6-phosphate dehydrogenase. In the presence of appropriate cofactors, ATP is by the synergistic operation of the enzymes repeatedly recycled, resulting in substrate amplification. The ultimately generated NADH is measured fluorometrically. By this approach, where the enzymatic degradation step and the detection step are completely separated, it is possible to operate them individually under optimal conditions. The amplification factor is directly proportional to the residence time of the sample zone within the enzyme reactor, which time might be manipulated by altering the flow-rate and in the extreme by performing stopped-flow experiments. Amplification factors between 15 and 1000 were obtained, but it was found that increased amplifications did not lead to significantly lower detection limits; thus, it appears that a practical lower limit of detection is of the order of 1-5 nM. An investigation of this paradoxical feature, and a possible explanation for it, is given.

Technology assessment in a user perspective--experiences with drug technology

Drugs have a central place among medical technologies, and medical technology assessment can learn from the established regulation of drug technology. This article outlines how users' experiences are not part of the basis on which decisions are made today, although this knowledge is imperative for identifying the problems that are not uncovered or foreseen by today's drug assessments. Further, users' interests might not be part of assessments that are based on the controlled clinical trial. A framework for drug technology assessments based on a user perspective is suggested.

Spectrophotometric flow injection determination of trace amounts of thiocyanate based on its reaction with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and dichromate: assay of the thiocyanate level in saliva from smokers and non-smokers

A simple and very sensitive spectrophotometric flow injection (FI) procedure for the determination of trace amounts of thiocyanate is described. The proposed method is based on the reaction between thiocyanate and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol, which, in 2 mol dm-3 acidic media in the presence of a strong oxidizing agent, produces an intensely coloured product. Several oxidants are potentially applicable, but it is shown that dichromate is preferable. As the reaction product formed is unstable and the signal inherently is recorded on a high background level, it is demonstrated that FI constitutes an ideal method in order to monitor reproducibly and repeatedly the kinetically transient signal that is obtained. Based on optimization by a factorial experimental design, the detection limit of the procedure was found to be 3.5 mumol dm-3, and the standard deviation between samples was 0.16 mumol dm-3. No significant interferences were observed; a 1000-fold excess of cyanide could readily be tolerated within the experimental error. With a sample volume of 50 microliters being injected, the sampling frequency was 60 samples h-1. The system was tested with saliva samples from non-smokers and smokers, and the results show that it is possible to distinguish between these two categories of individuals. As an added benefit, the detection limit of the analytical procedure allows the samples to be diluted 100-fold, so that centrifugation for 5 min is the only preliminary sample preparation that is necessary.

Development, use and evaluation of drugs: the dominating technology in the health care system

The article presents various perspectives of drug technology and health care policy in Denmark. Drugs dominate as the most widely used treatment technology in the health care system and the use of drugs is steadily increasing. The pharmaceutical industry's development of drugs is based on an economic estimate of developments, expenditures, marketing costs and the anticipated share of the market. Controlled clinical trials have become the main form of documentation required by the health authorities. This method is insufficient to evaluate the (side) effects of the drugs when in actual use. Drugs fit perfectly the technical perception of disease, a perception which prevails in the pharmaceutical industry, medical science and in the treatment of disease. This perception believes that a disease is due to an attack or dysfunction in the biological-mechanical conditions of the individual. Drugs offer a standard solution to health problems independent of the individuals' social life. Thus drugs become a tool which function in agreement with the disintegrated and achievement-orientated approach to disease as it is organized today. In general the statements in this article are not limited to special Danish circumstances but are valid for other countries as well [1, 2]. (Norris R. Pills, Pesticides & Profits. North River Press, 1982; Braithwaite J. Corporate Crime in the Pharmaceutical Industry. Routledge & Kegan Paul, London, 1984) The empirical data in this article derive from Denmark, however.

The active medicine user

The purpose of the study is to analyse medicine behaviour seen from the user's point of view. The study intends to generate ideas to specify topics of problems and to try out a combination of qualitative research methods. The practitioners and four asthmatic patients attached to a health centre in Billund, Denmark, were interviewed. The patients kept a diary based on topics, the notes of which were elaborated by weekly telephone interviews. In a final interview all participants evaluated the course of the study. The combination of qualitative methods has been very suitable to provide the perspective of the user. The results of the study question the ideal picture of the patient as a passive user of medicine. The main trends show that: the users develop different strategies to evaluate medication therapy; it has negative consequences to the patient when medication is changed regardless of patient experience; the therapy improves when the doctor draws on the experience of the patient. The study contributes to the present, sparse knowledge about the consciously acting user of medicine and indicates the importance of incorporating the user's experience and life situation in the health care system's handling of health problems.

Number and type of psychotropic drugs on the Scandinavian market in 1950-1977

This article describes the number and types of psychotropic drugs on the market in Denmark, Finland, Norway, and Sweden from 1950-1977. The total number of drugs on the market in each country depended greatly on how psychotropic drugs were defined, but trends with time and differences between the countries were less affected by this definition. The number of drugs was highest in Finland and lowest in Norway. In all countries, the number of drugs increased from 1950 to the mid-1960s, most abruptly in Finland. They then quickly decreased in Finland and Sweden, but remained fairly constant in Denmark and Norway. The number of different active substances was much smaller than the number of drugs, and the differences between the countries were also smaller. The proportions of combination and hidden psychotropic drugs in relation to all psychotropics were considerable in Finland and Sweden, and the varying numbers of combination drugs contributed greatly to the wide differences in the number of drugs. From the medical point of view, far too many drugs were on the market in that period.

Hydroxychloroquine sulphate in prevention of deep venous thrombosis following fracture of the hip, pelvis, or thoracolumbar spine

One hundred and fifty-three patients, forty-eight to ninety-seven years old, were included in a double-blind placebo-controlled investigation of the usefulness of hydroxychloroquine sulphate for the prevention of deep venous thrombosis in patients with fractures of the hip, pelvis, or thoracolumbar spine. The results indicated that this drug can reduce the number of thrombeombolic complications significantly (p less than 0.005), a finding that corresponds to the results obtained with other drugs such as coumarin derivatives or dextran 70.

Intra-arterial infusion of prostaglandin E1 in normal subjects and patients with peripheral arterial disease

Acute vasodilatation was produced by infusion of prostaglandin E1 (PGE1) in the femoral artery in 6 patients with occlusive arterial disease of the legs and in 3 normal subjects. The effect on blood flow and on blood pressure was measured at different segments of the leg with the strain gauge technique, isotope clearance technique, and photoelectric technique. Skin temperature was measured at different levels by using thermocouples. The blood pressure on the legs decreased at all segments during vasodilatation as well in patients as in controls. The blood flow increased in all segments in normal controls. In patients the blood flow increased proximally in the legs. Distally, however, no increase could be demonstrated. As a good effect of PGE1, on ischaemic rest pains has been reported, mechanisms other than vasodilatation should probably be considered.