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Biomedical subjects

R S Kahan

Publications and source records attributed to R S Kahan.

13 recordsLinked to original sources
PubMed2000

Reliability of radiographic observations recorded on a proforma measured using inter- and intra-observer variation: a preliminary study.

AIM: The aim of this preliminary study was to test the reliability of radiographic evaluation of features of endodontic interest using a newly devised data collection system. METHODOLOGY: Twelve endodontic MSc postgraduate students and one specialist endodontist examined sample radiographs derived from a random selection of 42 patients seen previously on an Endodontic New Patient Clinic (EDI). Each student examined a random selection of 8-9 roots on periapical radiographs of single- and multirooted teeth, with and without previous root canal therapy and 3-4 dental panoramic tomograms (DPTs). A total of 100 roots were examined. A proforma was used to record observations on 67 radiographic features using predefined criteria. Intra-observer agreement was tested by asking the students to re-examine the radiographs. The principle investigator and the specialist endodontist examined the same radiographs and devised a Gold Standard using the same criteria. This was compared with the student assessments to determine inter-observer variation. The postgraduates then attended a revision session on the use of the form. Each student subsequently examined 8-9 different roots from the pool of radiographs. A further assessment of inter-observer variation was made by comparing these observations with the Gold Standard. RESULTS: Of the 67 radiographic features, only 25 had sufficient response to allow statistical analysis. Kappa values for intra- and inter-observer variation were estimated. These varied depending on the particular radiographic feature being assessed. Fifteen out of 25 intra-observer recordings showed 'good' or 'very good' Kappa agreement, but only three out of 25 inter-observer observations achieved 'good' or 'very good' values. Inter-observer variation was improved following the revision session with 16 out of 25 observations achieving 'good' or 'very good' Kappa agreement. CONCLUSIONS: Modification to the proforma, the criteria used, and training for radiographic assessment were considered necessary to improve the accuracy and reproducibility of the observations entered.

Data Collection↗
PubMed1996

Evaluation of a pulse oximeter and customized probe for pulp vitality testing.

Current routine methods for assessment of pulp vitality rely on stimulation of A-delta nerve fibers and give no direct indication of blood flow within the pulp. Recent papers have suggested that pulse oximeters may be used to diagnose pulp vitality by detection of blood flow. In this study, an optimized pulse oximeter probe for teeth was designed, built and tested using the Biox 3740 Oximeter (Ohmeda, Louisville, CO). Following preliminary in vitro tests, the probe was tested clinically. Pulse waveforms from maxillary and mandibular anterior teeth were noted. Simultaneous readings from the subjects' finger were used as controls. Pulse wave readings from the teeth were found to be synchronous with the finger probe, but not consistently. It was easier to maintain continuous readings from mandibular incisors than from maxillary incisors. The average percentage synchronization with the pulse was 28.95% for maxillary incisors and 50.28% for mandibular incisors. This difference was significant (p = 0.05). The overall accuracy of the commercial instrument was disappointing, and in its present form it was not considered to have clinical value.

Artifacts↗
PubMed1995

Intentional replantation: a case study.

Intentional replantation (IR) involves the extraction, extra-oral endodontic treatment and replantation of a tooth. Its use dates back over 1000 years, but it is rarely considered by the modern dental practitioner. This paper describes the treatment of a patient using this technique, and discusses its relative advantages and disadvantages.

Adult↗
PubMed1987

Diabetes graphic aids used in counseling improve patient compliance.

This study found that a group of patients with diabetes counseled by a dietitian who used graphic teaching aids complied with health care advice better than did a control group advised by the same counselor without the use of graphic teaching aids. Both groups consisted of private patients in an Illinois clinic referred to the dietitian by their physicians. Group A, whose members received counseling with graphic aids (such items as models and charts of the eye, kidneys, arteries, nerve fibers, fat, and glucose levels), included six female and nine male patients with diabetes. Of them, six were insulin-dependent and nine were not. Group B, whose members received counseling without graphic aids, comprised six female and 7 male patients with diabetes. Of them, five were insulin-dependent, and eight were not. All were seen over a 90-day period. Compliance was assessed in six areas: (a) regular keeping of appointments, (b) decreasing fat consumption, (c) eating meals at regular intervals, (d) controlling portion size, (e) blood-glucose monitoring by patients with insulin-dependent diabetes, and (f) weight-loss by patients with noninsulin-dependent diabetes. Members of Group A, who received counseling accompanied by graphic aids, registered the highest rates of compliance in all six areas.

Adolescent↗
PubMed1977

Necrolytic migratory erythema. Distinctive dermatosis of the glucagonoma syndrome.

Glucagon-secreting tumors of the pancreatic islets (glucagonomas) produce a distinctive syndrome in which weight loss, diabetes mellitus, anemia,and prominent mucocutaneous findings occur. The cutaneous component-necrolytic migratory erythema--may be polymorphous, but most commonly manifests as erosions and crusts of the groin, perineum, buttocks, distal part of the extremities, and central area of the face. Alternatively, scaly papules and plaques may predominate in these areas. The eruption may resemble such dermatoses as pemphigus foliaceus, acrodermatitis enteropathica, chronic mucocutaneous candidiasis, psoriasis, and severe seborrheic dermatitis. Two patients with chronic, previously undiagnosed dermatoses had necrolytic migratory erythemia, which led to the discovery of glucagonomas present in each. In one patient surgical resection of the tumor resulted in total clearing of the rash within 48 hours. Awareness of this distinctive entity may lead to early diagnosis and, possibly, cure.

Adenoma, Islet Cell↗
PubMed1975

The effect of legalized abortion on morbidity resulting from criminal abortion.

In order to examine the effect of legalized abortion on the complications of criminal abortion, a surveillance system was established at a large urban hospital in Atlanta, Georgia. Between 1969 and 1973, legally induced abortions at this hospital increased logarithmically from 8 to 498 per quarter year. The number of women admitting to attempts at illegal abortion decreased significantly, but the decline began only after three years of increasing numbers of legal abortions. A slight decrease in the number of septic "spontaneous" abortions also occurred. Making legal abortion services available can result in a decrease in morbidity associated with illegal abortions, but the availability of legal abortion must be sufficiently broad to obviate having to resort to criminal means.

Abortion, Illegal↗
PubMed1969

Ethylene-controlled Induction of Phenylalanine Ammonia-lyase in Citrus Fruit Peel.

l-Phenylalanine ammonia-lyase (PAL) activity is low in the external layers (flavedo) of intact mature grapefruit peel. Flavedo discs evince upon incubation increasing PAL activity and ethylene production. Light has no effect in enhancing PAL activity in discs. Exogenous ethylene stimulates PAL activity in the flavedo of intact mature grapefruits (half maximum stimulation at 15 ppm); such activity rapidly decreases when fruit is removed from the ethylene containing atmosphere. Carbon dioxide inhibits both ethylene production and PAL activity of discs; exogenous ethylene only partly relieves PAL inhibition. Cycloheximide inhibits both PAL activity and ethylene production by flavedo discs. The same concentration of cycloheximide also inhibits PAL activity of discs in the presence of exogenous ethylene. Protein synthesis seems therefore to be needed at both levels of ethylene evolution and enhancement of PAL activity.

Journal Article↗