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Biomedical subjects

C Maxwell

Publications and source records attributed to C Maxwell.

At least 37 records · Page 2Linked to original sources
PubMed1987

Clinical trials in hypertension: some general thoughts and some particular controversies.

A common fallacy in the analysis of clinical trials is described. Correlating the differences between pairs of random numbers and the first of them produces a correlation coefficient of 0.71 with a regression equation of y = -4.5 + X. Misuses of correlation and regression in hypertension and hypolipidaemic trials are described and advice given. The author also puts on record his objection to the pedantry that surrounds the use of the analysis by intentions-to-treat method. Patients who go into such an analysis may include those who never received a single dose of the treatment to which they were randomized, those who started it but were later switched to the other treatment though still analysed in their original group, patients who could be regarded as having died from obviously nontreatment causes by any sensible and reasonable doctor, and patients later found even to have suffered the wrong illness.

Antihypertensive Agents↗
PubMed1987

The clinical and immunologic responses of normal human volunteers to low dose hookworm (Necator americanus) infection.

Five normal human volunteers were exposed to approximately 50 infective larvae of Necator americanus and were observed for the development of clinical signs or symptoms and for changes in blood eosinophil levels, IgG antibody titers, total and parasite-specific IgE, and lymphocyte blastogenic responses for 6-10 weeks. Bronchoalveolar lavage was performed on four subjects prior to infection and at times when larval migration through the pulmonary tree was likely. Eggs were demonstrated in the stools of four volunteers who remained untreated for more than 6 weeks; one volunteer had to be treated at day 40 because of severe gastrointestinal symptoms. All others also complained of abdominal pain and flatulence between days 35-40. All volunteers developed marked blood eosinophilia which peaked between days 38-64 and ranged from 1,350-3,828 eosinophils/mm3. Small increases in total and parasite-specific IgE and IgG were noted in some volunteers. One volunteer showed a significant lymphocyte blastogenic response. With the exception of mucosal erythema, bronchoalveolar lavage results were unremarkable. Our data indicate that a single small inoculum of hookworm larvae is capable of producing significant transient gastrointestinal morbidity and marked blood eosinophilia but does not induce other prominent T cell- and B cell-dependent immune responses.

Adult↗
PubMed1985

Assimilation of cholesterol by Lactobacillus acidophilus.

Considerable variation was found among strains of Lactobacillus acidophilus isolated from the fecal flora of pigs with regard to the ability to grow well in the presence of bile and to assimilate cholesterol from a laboratory growth medium. The uptake of cholesterol occurred only when the culture(s) was growing in the presence of bile under anaerobic conditions. Consumption of L. acidophilus RP32, which was selected for its ability to grow well in the presence of bile and to assimilate cholesterol from the laboratory medium, significantly inhibited increases in serum cholesterol levels of pigs (P less than 0.05) fed a high-cholesterol diet. Consumption of L. acidophilus P47, which was selected for its ability to grow in the presence of bile and lack of ability to remove cholesterol from the growth medium, failed to have a similar effect. This indicates that certain strains of L. acidophilus act directly on cholesterol in the gastrointestinal tract, and thus may be beneficial in reducing serum cholesterol levels.

Anaerobiosis↗
PubMed1984

An arterial blood gas interpretation program for hand-held computers.

Because of its portability, the hand-held computer can be easily used at the bedside to perform mathematical computations and assist with patient care decision making. This paper describes applications software for arterial blood gas interpretation with the hand-held computer. From the arterial blood gas values entered, the program calculates the arterial/alveolar PO2 ratio (a/A PO2), provides an interpretation of oxygenation, a/A PO2, ventilation, and acid-base status, and makes suggestions for therapy. This program can be used for the individualized bedside teaching of students and others with limited experience in arterial blood gas interpretation.

Blood Gas Analysis↗
PubMed1983

A spirometry/interpretation program for hand-held computers.

The recent introduction of the hand-held computer has provided an important new tool for the medical team. The device is inexpensive, portable, and operator-programmable in BASIC. We describe software for a spirometry program with computer-generated interpretation as an example of numerical calculation and logical decision making.

Computers↗
PubMed1982

Hospital organizational response to the nuclear accident at Three Mile Island: implications for future-oriented disaster planning.

The 1979 nuclear accident at Three Mile Island (TMI) near Harrisburg, Pennsylvania, caused severe organizational problems for neighboring health care institutions. Dauphin County, just north of TMI, contained four hospitals ranging in distance from 9.5 to 13.5 miles from the stricken plant. Crash plans put into effect within 48 hours of the initial incident successfully reduced hospital census to below 50 per cent of capacity, but retained bedridden and critically ill patients within the risk-zone. No plans existed for area-wide evacuation of hospitalized patients. Future-oriented disaster planning should include resource files of host institution bed capacity and transportation capabilities for the crash evacuation of hospitalized patients during non-traditional disasters.

Disaster Planning↗
PubMed1981

Clinical trials, reviews, and the Journal of Negative Results.

1 Eighteen our of twenty non-significant placebo controlled trials are shown to have trends favouring imipramine and are consistent with a further ten significant at 0.05. 2 The problems of falsely positive and falsely negative results are discussed. A plea is made to medical journal editors to publish 'negative' or null difference trials by title only; rather than not at all.

Clinical Trials as Topic↗
PubMed1980

The use of an inexpensive, general purpose microcomputer in quantitative cytochemistry.

A 32K Commodore Pet microcomputer has been interfaced with two Vickers microdensitometers. This system allows for the simultaneous logging of data from two densitometers being operated independently of each other. Software for the statistical analysis of data generated by the densitometers, and for use with the cytochemical bioassay of hormones, is described. The densitometer/Pet system is relatively cheap, reliable, and readily adaptable to other applications.

Computers↗
PubMed1978

Sensitivity and accuracy of the visual analogue scale: a psycho-physical classroom experiment.

1 Twenty-seven intelligent volunteers took part in a classroom experiment on two occasions to assess subjectively, ordinally related volumes of sound (offered in random sequence), using the visual analogue scale. 2 It was simple to use and largely acceptable. Big differences were significant by parametric tests but small ones were sometimes significant only with ordinal ones. Within-subject comparisons were more accurate and more sensitive than those between-subjects. The t-test was very robust. 3 Five out of 49 results were erroneously significant; they remained so no matter how the data were handled. It was concluded that this was due to a shift in either perception, cognition or scoring between the two sessions. 4 Arcsine transformations made little difference. The mechanism of these is fully discussed. A conversion to proportional scores resulted in very much improved sensitivity. 5 It is recommended that authors using the visual analogue scale: have valid reason in their own setting for using a transformation; present the distribution, or at least the medians and ranges of their raw scores; also use a simple but different measure so as to demonstrate internal consistency between them.

Adult↗
PubMed1978

A novel adaptation of the information game for the development of a new drug.

Medical advisers in the pharmaceutical industry have an important function and place in the development and evaluation of new drugs. Although mainly involved in the human and clinical investigations, it is essential that they have the background knowledge and experience to evaluate the results of pre-clinical studies and to apply these safely and effectively to the clinical situation. It is rare nowadays for a medical adviser to obtain direct experience in all areas of drug research due to its complexity. Simulation exercises are a means of obtaining this experience without suffering the results of a wrong decision. An adaptation of the Information Game proved to be a useful and acceptable means of illustrating the decisions that need to be made in a drug development programme and at the same time provided experience in coping with the various problems that might arise in such a programme. The training objectives of the game should be clearly defined at the outset in order to concentrate on the parts of the game that really matter and cover the maximum number of teaching opportunities.

Decision Making↗