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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↗
PubMed1988

Ultrastructural study of synovial membrane from the antebrachiocarpal joint of calves.

The synovial intima from the antebrachiocarpal joint of 4-month-old calves was between 1 and 3 cells in thickness and did not have a basal lamina. Numerous areas of the intimal matrix were in direct contact with the joint lumen. The synovial membrane was comprised mainly of A-type synoviocytes usually located adjacent to the joint lumen. These cells were characterized by numerous filopodia (or lamellipodia), large, empty-appearing vacuoles, numerous lysosomes, large vacuoles containing granular material separated from the vacuolar membrane by a radiolucent band, and coated micropinocytotic vesicles. Smooth micropinocytotic vesicles were seen only rarely in these cells. In contrast, B-type cells had few filopodia, numerous smooth micropinocytotic vesicles, few coated micropinocytotic vesicles, a well-developed Golgi apparatus and rough endoplasmic reticulum, mitochondria that were longer and had a denser matrix than that of A cell mitochondria, and surprisingly, only few maturing or fully formed secretory granules. A distinct intermediate (C or AB) type synoviocyte could not be unequivocally identified. Desmosome-like structures were present between synoviocytes, although it was considered questionable if these were true intercellular junctions. No other junctions were present.

Animals↗
PubMed1986

Logistic analysis of risk factors in acute retinopathy of prematurity.

In a prospective study of 328 high-risk neonates, we used computer-assisted logistic regression of 47 potential risk factors to study acute retinopathy of prematurity. Only four factors were significant in the logistic regression equation: ventilator hours, xanthine administration, birthweight, and maternal bleeding. Xanthine administration was identified as a new independent and significant (P less than .0001) predictor of acute retinopathy of prematurity.

Female↗
PubMed1986

Corneal epithelial cells produce thromboxane in response to interleukin 1 (IL-1).

Synthesis of thromboxane, a product of arachidonic acid formed via the cyclooxygenase pathway, was studied in rabbit corneal epithelial cells (SIRC cell line) under resting conditions and under the influence of interleukin 1 (IL-1). IL-1 potentiated the production of thromboxane 3-10-fold in a dose-dependent manner. This finding assumes added significance in view of the previous observations that the same cells are capable of producing IL-1. Thus, the corneal epithelial cells may be viewed in this context as an autocrine cell producing two biologically active substances which can serve as mediators of inflammation, one of which can augment the production of the other.

Animals↗
PubMed1985

Special considerations in bovine orthopedics and lameness.

This article discusses the features that make bovine orthopedics a unique area. Changes in methodology and design of internal fixation devices are considered, particularly as they differ in application to the different age and weight categories. Pediatric and economic considerations and the importance of client communications are reviewed in detail.

Age Factors↗
PubMed1985

Principles and application of internal fixation in cattle.

The principles of bone healing and vascular and periosteal responses are considered in relation to different methods of fracture fixation and complications. Advantages and disadvantages of the available internal fixation devices are reviewed for the fractures that most commonly occur in the different age groups.

Animals↗
PubMed1985

Alternatives to amputation.

Amputation of the digit of valuable animals is an inappropriate technique for resolving the serious infective processes that involve the important structures of the distal interphalangeal region. Surgeons should be able to recognize the early clinical signs and radiographic indications of three distinct, but interrelated, phenomena--the septic joint, the retroarticular abscess, and the complication of tenovaginitis. Tenovaginitis depends on either the septic joint or retroarticular abscess for its etiology. In any of these complications, the effective treatment will be based on the removal of diseased tissue and on irrigation with drainage of the area, followed by the elimination of mechanical forces or movement in the affected region.

Abscess↗
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↗