Design of a test system for fast time response fibre optic oxygen sensors.

A test system has been developed that can be used to calibrate and determine the time response, linearity and temperature sensitivity of a fibre optic oxygen sensor. The simple system obviates the need for precision gas standards and the requirement to generate a true square wave step response, which is seldom achievable. The sensor is mounted in a small chamber containing air or a known fraction of oxygen. By means of a computer-controlled switch, the absolute pressure within the chamber can be changed rapidly to a new steady state value. The partial pressure of oxygen changes in direct proportion to the absolute pressure, and so the accuracy and linearity and response time of the PO(2) calibration are limited only by those of the absolute pressure sensor. The temperature sensitivity of a commercial sensor and a means of correction are also described.

Cell wall-deficient bacteria as a cause of infections: a review of the clinical significance.

Cell wall-deficient bacteria (CWDB) are pleomorphic bacterial forms. These atypical organisms may occur naturally or they can be induced in the laboratory. Their presence has been known about for over a century, but a definite link to clinical disease outcomes has not been demonstrated. A number of case reports and laboratory studies suggest some disease associations, however. Considerable controversy surrounds the true relevance of CWDB to disease; there is a widespread belief that they may represent a response by the walled organism to adverse extracellular conditions like antibiotic pressure. This review looks at studies published between 1934 and 2003, which were identified by Dialog DataStar using the key words 'cell wall deficient bacteria and clinical significance and infections' and by further scanning the reference list at the end of the papers retrieved. We conclude that the evidence for the clinical significance of CWDB in disease is not compelling.

Facilitated communication: the effects of facilitator knowledge and level of assistance on output.

Investigated facilitated communication with 10 adults with autism, and specifically examined the effects of facilitator influence and level of assistance as a function of facilitator knowledge of experimental stimuli. Six men and four women with autism served as subjects, ranging in age from 14 years to 51 years of age. Each subject had 6 experimental sessions, 2 with no help, 2 with partial assistance, and 2 with full assistance. Within each session, the facilitator had knowledge of the experimental stimuli in one half of the trials. Results revealed no cases of correct responding independent of facilitator knowledge of correct answers. Additionally, facilitator control was apparent in numerous cases in which typed output matched stimuli to which the facilitator, not the subject, had been exposed. Results suggest that clinical and educational use of the procedure should be curtailed pending further experimental investigation.

Genetic, immunologic and biotransformation studies of patients on procainamide.

This report represents follow-up observations of a unique long-term study of patients on procainamide (PA) for various cardiac arrhythmias. Serologic and clinical evaluations associated with drug-related autoimmunity were assessed and patients were characterized for factors postulated to influence susceptibility to autoimmunity, including acetylator phenotype, oxidative metabolism of PA, HLA class profile, and production of interleukin-1 (IL-1) and tumor necrosis factor (TNF). Fifty-two percent had IgM and 70% IgG antibodies to total histones; 67% had IgG antibodies to histone H2A/H2B. Patients were equally divided between fast and slow acetylators. N-oxidative metabolism of PA was indicated by the presence of urinary nitroprocainamide, which correlated with elevated titers of antihistone antibodies. There was a significant incidence of the DQw7 split of DQw3 in PA patients when compared to controls, and the frequency of antibodies to total histones and H2A/H2B was significantly increased in the DQw7 patients. C4A*QO and C4B*QO alleles were more frequent in the PA patients than in controls. IL-1 and TNF production was not different in patients compared to controls. These data suggest that certain genetic factors may serve as markers for PA-related autoimmunity.

Disparity in HLA-DR typing and mixed lymphocyte culture reactivity.

Prospective HLA-DR matching has been shown to enhance renal graft survival. It has also been demonstrated that the major stimuli in the one-way mixed lymphocyte culture reaction (MLR) are the DR rather than DQ class II histocompatibility antigens. A two antigen DR match between the potential recipient and donor is usually associated with a negative MLR. The findings of two family studies are reported in which HLA-DR identity between the potential recipient and donors did not correlate with the MLR reactivity. These findings further strengthen the need for performing the MLR in conjunction with DR/DQ typing since splits have been described for some of the DR antigens which may not be detected using the currently available commercial typing trays.

The influence of signal loss on the comparison between computer analyses of the fetal heart rate in labour using pulsed Doppler ultrasound (with autocorrelation) and simultaneous scalp electrocardiogram.

A comparison between the computer analyses of records of the fetal heart rate (FHR) obtained simultaneously by pulsed doppler ultrasound with autocorrelation and by fetal scalp electrocardiogram (ECG) in labour showed no statistical differences when signal loss was less than 2%. Increasing signal loss, due to maternal movement, correlated significantly with greater differences between ultrasound and ECG values for mean FHR variation (r = 0.58, p less than 0.005). With higher signal loss (average 15.6%) the mean FHR variation measured by ultrasound was significantly lower than that measured by ECG (T = 3.83, p less than 0.005) but this reduction was not of clinical significance.

Teaching life skills to adults disabled by autism.

The acquisition of life skills is a high priority for adults disabled by autism who are living in community-based residential programs. A training program was implemented and evaluated that consisted of analyzing life skills into component steps and providing increasing levels of assistance according to a predetermined schedule. Five adults who were severely disabled by autism and who lived in group homes in the community served as participants. All five adults showed progress in targeted life skills, and four of the five achieved independence on their targeted skills. The usefulness of this training model in community-based residential programs is discussed.

[Clinical course and pathomechanisms of chronic granulomatosis]. / Klinik und Pathomechanismen der chronischen Granulomatose.

Chronic granulomatous disease (CGD) is characterized by frequent uncontrollable infections which often lead to death in early childhood. The first clinical signs may be confined to the skin and manifest themselves as abscesses, pyoderma, eczema or draining sinuses. Frequently, lymph nodes, spleen, lungs or liver are also involved. The basic defect is a failure of leukocytes to kill certain bacteria or fungi. The exact biochemical defect is however not yet known. The diagnosis of CGD is based on the clinical picture and on a defect of the granulocytes, as proven by bactericidal, NBT-reduction or chemiluminescence tests. In most and possibly in all of the cases, the disease is X-linked, and the CGD-gene has been regionally assigned to the X-chromosome. The existence of a second type of CGD with autosomal recessive inheritance has been assumed by several authors. In order to improve the prognosis of CGD, it is essential that the disease is diagnosed as early as possible so that prompt treatment can be given.

Development of methods for quantitative analysis of the fetal heart rate.

A description is given of the development of methods for the quantitative analysis of measurements of the fetal heart rate, uterine pressure and fetal movements, with data collection, reduction and analysis via a digital cassette off-line, or on-line. The on-line system consists of a small microprocessor, which reduces and digitizes the data, and which passes it for display and analysis to a larger microprocessor (NASCOM Z80). Analysis on-line offers the opportunity of interaction to optimise record quality and to compare at once sequential records on the same patient.

PRESC: an interactive program for radiation therapy prescriptions.

An interactive program for prescribing radiotherapy treatments has been developed with the aim of improving radiation dose accuracy by preventing mistakes in quantitative data handling and calculations. The program also aims to decrease the time required to prescribe treatments and check the calculations. The interactive dialogue closely follows present, manual methods of prescription. The program provides a comprehensive choice of treatment options which either individually or in combination cover all the treatments carried out on the Cobalt units for which the program was designed. Each of the treatment options has been highly optimized to reduce the amount of data entered and for ease of use. The program allows changes to the prescription at time of entry and during the treatment course. The treatment sheet and patient record resulting from the interactive dialogue are discussed and compared with the existing system. The modular program structure is described and some of the results from use of the program are discussed. Possible future improvements are outlined.

A microcomputer system for prescription, calculation, verification and recording of radiotherapy treatments.

The design of a microcomputer system for the reduction of mistakes in radiotherapy is described. The system covers prescription entry, prescription and treatment calculations, and verification and recording of the treatment set-up. A telecobalt unit was interfaced to the system and in the first 12 months 400 patients have been prescribed and 5000 treatment fields verified. The prescription is entered by the medical officer using an interactive program and this prescription provides the reference for verifying the treatment set-up. The program allows amendments to the prescription to be made easily during the treatment course. The treatment parameters verified are field size, wedge and treatment time. The system uses bar-codes for patient and field identification. A reduction in the number of mistakes has been achieved and future developments are discussed.

Barium oxalate as a selective solid reagent for the absorption of sulphur trioxide.

Barium and calcium oxalate monohydrates have been shown to be more suitable absorbents for sulphur trioxide than either anhydrous or hydrated oxalic acid. All four compounds are selective absorbents for the trioxide and do not absorb sulphur dioxide. Similarly all are elective absorbents for sulphuric acid aerosol, although the calcium salt may be decarboxylated under these conditions. Lead oxalate and formate may be suitable for the absorption of SO(3) and H(2)S, and SO(3), H(2)S and SO(2) respectively.

Ambient air contamination in a dental outpatient theatre.

The extent of air contamination by halothane in an operating session was correlated with the number of patients, the total usage of halothane, refilling a vaporizer and the number of hyperventilating patients per session. Trichloroethylene content of theatre air correlated only with total usage and refilling a vaporizer. A very strong personal association (P smaller than 0.001) was found between the anaesthetist and the extent of air contamination with halothane. The association was weaker (0.05 less than P less than 0.1) for trichloroethylene. The median ambient air contamination with halothane in the vicinity of the faces of anaesthetists and dental surgeons was between six and nine times greater than the median air contamination at the fixed sampling sites (P smaller than 0.005).

Titrimetric determination of microgram amounts of bismuth after precipitation as Bi[Cr(SCN)(6)] followed by thiocyanate amplification.

Bismuth (10-100 mug) is precipitated as Bi[Cr(SCN)(6)]. After filtration, the precipitate is treated with bicarbonate solution, and the thiocyanate dissolved is oxidized by iodine in alkaline medium to sulphate. After acidification, the excess of iodine is extracted into chloroform, and the iodide in the aqueous solution is amplified by bromine oxidation and subsequent treatment with more iodide. The titrimetric procedure provides 228 iodine atoms for each original bismuth ion. Only Hg(2+)(2), Hg(2+) and AsO(3-)(4) interfere seriously.

Keratinizing dermatoses. Combined data from four centers on short-term topical treatment with tretinoin.

In four medical centers, 40 patients with keratinizing dermatoses were treated with topical tretinoin (vitamin A acid) 0.1% cream and salicylic acid 2% cream in a short-term, double-blind study. Tretinoin was the more effective treatment for several of the keratinizing dermatoses with the exception of palmar-plantar hyperkeratosis, for which it was not effective in the concentration and method of application used. The most striking clinical responses occurred in patients with lamellar ichthyosis and ichthyosis vulgaris. Local adverse reactions-chiefly pruritus, erythema, burning, excoriation, and irritation-were not severe and could be controlled by modification of the treatment regimen.