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Biomedical subjects

C R Morris

Publications and source records attributed to C R Morris.

At least 73 records · Page 4Linked to original sources
PubMed1981

Image distortion in rotational panoramic radiography. III. Inclined objects.

Mathematical calculations have been performed to analyse how accurately the angle between objects, inclined in space, is reproduced on panoramic films. A marked tolerance against angle distortion was found. Angular measurements may be performed on correctly exposed panoramic films, and the values obtained are satisfactorily accurate for most clinical purposes.

Mathematics↗
PubMed1981

Image distortion in rotational panoramic radiography. IV. Object morphology; outer contours.

On films exposed with rotational panoramic radiography, distortion effects are often apparent. The distortion of the outer contour of three-dimensional model objects jas been analysed mathematically. The applied mathematical expressions for coordinate transformation between object and film were confirmed experimentally. The distortion of the outer contour is dependent on the basic form of the object; the more rounded the object is, the less marked is the distortion. It is concluded that for practical clinical purposes the correctly exposed panoramic film is reliable when the form of rounded objects is assessed.

Mathematics↗
PubMed1981

Image distortion in rotational panoramic radiography. I. General considerations.

The projection system in rotational panoramic radiography is complex in the respect that there are two projections of the object working simultaneously, one in the horizontal and one in the vertical dimension, giving rise to distortion of three-dimensional objects in the image. A mathematical method is presented for transforming data from three-dimensional objects to image data. This method may be used when analysing different distortion effects inherent in panoramic films.

Mathematics↗
PubMed1980

Panoramic radiographic survey of dentists participating in ADA health screening programs: 1976, 1977, and 1978.

Results of the panoramic examination of dentists participating in the health evaluation program of the ADA annual sessions held at Las Vegas (1976), Miami Beach (1977), and Anaheim (1978) were reported and compared as accurately as possible with the results of the panoramic examinations of dentists taking part in the health evaluation programs of the ADA annual sessions in 1964, 1966, and 1968. The panoramic radiograph continues to serve as a diagnostic aid in dental health evaluation programs. Only general impressions may be drawn from surveys of this nature for various reasons: the inability to follow up each case with a clinical examination; the lack of correlation of findings between examiners; and the use of different criteria each year. Generally, dentists examined in the health evaluation programs in 1976, 1977, and 1978 were in good dental health.

Adult↗
PubMed1980

A blueprint for hospitalwide quality assurance.

Hospital medical staffs currently are faced with the task of writing a quality assurance plan that will meet the requirements of JCAH's new standard for integrating quality assurance activities on a hospitalwide basis. The following article details the essential components of a written quality assurance plan and the special procedural requirements that must be spelled out in the written statement.

Medical Staff, Hospital↗
PubMed1980

Estimating creatinine clearance in children: comparison of three methods.

Three methods of estimating creatinine clearance (Clcr) in children were compared in pediatric patients ranging in age from 1 to 16 years. Sixty-eight measured Clcr determinations, normalized to ml/min/1.73 sq m of body surface area, were performed on 58 patients. Estimated Clcr values were calculated using the methods of Schwartz et al. (Method I), Shull et al. (Method II), and Rudd et al. (Method III), and each method was correlated with the measured creatinine clearance. Mean prediction error (estimated Clcr minus measured Clcr) also was compared for the methods to assess the relative prediction accuracy. Measured and estimated Clcr values correlated well (Method I, r = 0.90; Method II, r = 0.85; Method III, r = 0.80; p less than 0.0001). Mean prediction errors for Methods I and III (4.1 and -2.8 ml/min/1.73 sq m, respectively) were not significantly different; however, both methods were significantly more accurate (p less than 0.01) than Method II (mean prediction error: -17.4 ml/min/1.73 sq m). In this study, Method I, which was based on height and serum creatinine, was found to have the greatest accuracy and simplicity and to be the most clinically useful method of the three methods. The applicability of the three methods to pediatric patients with severe renal disease is uncertain.

Adolescent↗
PubMed1979

Improvement of pulse-mode photographic images in MDS computer systems.

Users of scintigraphic computer systems manufactured by Medical Data Systems (MDS) frequently experience textured distortion of oscilloscope images when scans are produced by Z-axis modulation. The source of this malfunction has been identified and a way to eliminate the problem is described. The modification is simple and inexpensive. The availability of Z-axis modulation significantly enhances the capabilities of MDS systems.

Computers↗
PubMed1978

The patient's greatest hazard.

To reduce the patient's hazard in the dental office, the dentist must take a medical history, perform a limited medical examination, order and interpret laboratory tests when indicated, initiate medical consultation when necessary, and evaluate the data obtained in order to make appropriate treatment modifications for high risk patients. The current status of health which our population enjoys must not be confused with a status of robustness. An apparently well patient may be in great jeopardy while you are delivering the most skillful dental care unless adequate precautions are taken.

Blood Coagulation Disorders↗
PubMed1977

Antileukemic properties of combinations of radiation and malonato(1,2-diaminocyclohexane) platinum(ii) (NSC-224964).

Mean survival times were increased an average of 23, 53 and 61%, when 10, 15, and 20 mg/kg, respectively, of the organoplatinum congener, malonato(1,2-diaminocyclohexane) platinum(II)(NSC-224964), was given as the only treatment modality to BDF1 mice bearing 1-day-old L1210 leukemia. When a single dose of 10 mg/kg was combined with either 300 or 100 R on day 1 only, the anticipated response (ILS = 30 and 38%, respectively) based on the additive effects of the single modalities was surpassed by 26 and 21%, respectively (i.e. extent of therapeutic synergism). When divided doses of radiation (200 R/day x 3 days) were combined with 15 or 20 mg/kg of NSC-224964, survival times were enhanced an average of 15% (extent of synergism) greater than would be expected if these modalities were acting through an additive process(es).

Animals↗
PubMed1976

The effects of single administration of an antitumor platinum compound on ornithine decarboxylase activity in certain tissues of mice bearing L1210 leukemia.

A single dose of cis-dichloro(dipyridine)platinum(II) (cis-PPC), when given to BDF1 mice bearing 1-day-old L1210 leukemia, suppressed the increase of spleen and liver ornithine decarboxylase (ODC) activity which occurs concomitantly with development of the leukemia. The inhibition of ODC, the rate-limiting enzyme in polyamine synthesis, appeared to correlate with the prolonged chemotherapeutic efficacy of a single dose of the platinum complex. These observations suggest an additional mechanism by which platinum complexes express their antitumor actions and, in addition, support the view that polyamine synthesis and excretion patterns can be used as predictors of chemotherapeutic response.

Animals↗