Search PubMed⌕ Search

Biomedical subjects

J G Ferguson

Publications and source records attributed to J G Ferguson.

At least 19 recordsLinked to original sources
PubMed1992

Life tables for clinical scientists.

The life-table, or Cutler-Ederer, method of survival analysis is a simple and efficient means of estimating the probability that the first instance of an event will occur in a given period of time in studies complicated by incomplete patient follow-up. This discussion is designed to acquaint the nonstatistician with the general concepts, assumptions, advantages, and disadvantages of life-table analysis. The arcane nature of the calculations frustrates attempts at simplification. A glossary of statistical terms and sample calculations are provided for interested readers.

Humans↗
PubMed1991

Incremental prognostic accuracy of clinical, radionuclide and hemodynamic data in acute myocardial infarction.

A logical sequence of testing in evaluating prognosis early in acute myocardial infarction (AMI) would be to use clinical data first, then add noninvasive data and finally add invasive data. The incremental prognostic information concerning 1-year survival obtained from such a sequence in 107 patients with AMI was studied using logistic regression and receiver-operating characteristic curves. Cardiac mortality was 24% at 1 year. Clinical data obtained soon after admission (prior myocardial infarction, heart rate, blood pressure, age) were 78 +/- 5% accurate in the prediction of 1-year survival. The addition of radionuclide-estimated left ventricular ejection fraction or invasive hemodynamic data to the clinical model at this time improved prognostic accuracy to 84 +/- 5% (p = 0.05) and 87 +/- 4% (p = 0.007), respectively. The further addition of invasive data to the model containing clinical and left ventricular ejection fraction data provided a further increment in prognostic accuracy to 89 +/- 4%, whereas no significant increase in accuracy was seen on addition of left ventricular ejection fraction to the model containing clinical and invasive data. It is concluded that clinical data provide important prognostic information concerning late survival early in the course of AMI. This may be improved by the logical application of noninvasive and invasive studies at this time.

Adult↗
PubMed1989

Limitations of a conventional logistic regression model based on left ventricular ejection fraction in predicting coronary events after myocardial infarction.

The clinical utility of conventional logistic regression models based on left ventricular ejection fraction (LVEF) for the prediction of cardiac events (death or recurrent infarction) was assessed in 646 postinfarction patients undergoing radionuclide ventriculography at rest and during exercise. The discriminant power of 2 different models (LVEF at rest alone vs LVEF at rest plus LVEF at peak exercise) was quantified in terms of the area under receiver-operating characteristic curves based on knowledge of patient outcome in the year after testing and the logistic probability of that outcome. Although LVEF at rest provided a significant amount of prognostic information (receiver-operating characteristic curve area = 62 +/- 4%, p less than 0.001), several limitations were observed: (1) powerful predictors of risk were uncommon (32% of patients with an LVEF at rest less than 0.20 had a cardiac event, but only 3% of the population had such extreme values); (2) the accuracy of predictions for high risk patients was less than for low risk patients (28 vs 98%, p less than 0.001); (3) addition of exercise LVEF to the model did not improve the accuracy of prediction (receiver-operating characteristic curve area = 68 +/- 4%, p = 0.11); and (4) predictions for individual patients were very imprecise (the 95% confidence interval of percent risk for an LVEF at rest of 0.20 [11 to 36%] overlapped that for an LVEF at rest of 0.60 [0 to 14%]).(ABSTRACT TRUNCATED AT 250 WORDS)

Death, Sudden↗
PubMed1979

A cytologic aid to diagnosing congenital glaucoma.

Using the Giemsa and Papanicolaou staining methods, the authors studied the superficial corneal epithelium of 17 glaucoma patients and 25 normal patients. Smears of the normal patients exhibited a high frequency of precornified cells and a paucity of cornified cells with pyknotic nuclei. Smears of the glaucomatous patients illustrated striking tinctorial changes; these changes were so pronounced that examination of a single section strongly suggested a diagnosis of glaucoma. A case report is presented in which a preliminary diagnosis of congenital glaucoma was disproved by these staining techniques.

Adolescent↗
PubMed1978

Tibiotarsal arthrodesis in a Moufflon sheep.

Restraint of a mature Moufflon sheep resulted in severe fracture and luxation of a previously osteoarthritic tibiotarsal joint. Arthrodesis was accomplished by means of internal pin fixation and an external fiberglass cast. After 3 months of hospitalization, the ram was returned to the original flock. Competition for dominance within the flock resulted in physical trauma to the ram. Seven months after surgery, the ram sustained a fractured ulna and died from exposure.

Animals↗
PubMed1978

Hospital counseling in Khartoum: a study of factors affecting contraceptive acceptance after abortion.

This study examines the impact of contraceptive counseling on 3 263 women hospitalized in Khartoum for treatment of incomplete abortion. The analysis which focused on education and parity/child desire, revealed that the counseling program produced contraceptive acceptance among 47.0% of those followed up. In spite of the counseling efforts, half of the women in this study did not accept contraception following the abortion-regardless of education or parity/child desire. It is difficult to determine why 50% of those who had recently undergone an incomplete abortion were willing to put themselves at risk again. Apparently, future efforts to increase the impact of counseling programs must also examine patients' motivation to accept (or not to accept) contraception.

Abortion, Incomplete↗
PubMed1977

Trabeculectomy.

During a one-year period, 31 trabeculectomies were done in 25 patients. Of these procedures, 27 (87%) were done for chronic open angle glaucoma, three (10%) for congenital glaucoma, and one for chronic open angle glaucoma in an aphakic patient. Our overall success rate was 87%. Complications were few: only two of 31 flat anterior chambers persisted postoperatively. Visual acuity dropped significantly (two lines on the Snellen visual acuity chart) in only one patient.

Adolescent↗
PubMed1977

A cytologic aid in the diagnosis of congenital glaucoma.

The superficial corneal epithelium of 17 patients with glaucoma varying in age from nine days to 16 years and 25 normal individuals varying from nine months to 16 years were studied comparing findings using the Giemsa and Papanicolaou staining methods. The normal individuals exhibited a high frequency of precornified cells and a paucity of cornified cells with pyknotic nuclei. Smears of 16 of the 17 patients with glaucoma stained by the Papanicolaou method illustrated striking tinctorial changes. In a 9-day-old patient with glaucoma there were occasional normal cells, but many others varied greatly both in shape and size. In addition, highly cornified, deep orange, Papanicolaou stained cells with pyknotic nuclei were noted. These changes were so pronounced that examination of a single section strongly suggested a diagnosis of glaucoma. Cells in the older patients (6 to 16 years) frequntly exhibited a high degree of cornification, extensive cell fragmentation, darkly stained pyknotic nuclei, and areas of ghost cells. The cytologic characteristics of stained corneal epithelium cells were a demonstrable aid in the early diagnosis of glaucoma.

Adolescent↗
PubMed1976

Penetrating keratoplasty: a computer analysis.

A computer analysis of 87 penetrating kertoplasties done in a uniform manner by a single surgeon revealed the following: 1. On a statistical basis small grafts (7.0 mm) provided better visual acuity than larger grafts (8.0 mm). 2. On a statistical basis small grafts will be clearer postoperatively than larger grafts. 3. On a statistical basis the age of the donor is not related to either graft clarity or visual acuity.

Adolescent↗