Search PubMed⌕ Search

Biomedical subjects

T R Knapp

Publications and source records attributed to T R Knapp.

At least 37 records · Page 2Linked to original sources
PubMed1989

Age, cohort, and time-period confounds in aging research.

1. Cross-sectional studies of age-related changes or developmental patterns contain the inherent confound of age and cohort. 2. Longitudinal studies of age-related changes or developmental patterns contain the inherent confound of age and time-period. 3. Many complex research designs and decision rules have been developed in an attempt to disentangle these confounds. These designs and decision rules are only useful if their assumptions are met. 4. It is important to logically determine when the age, cohort, and time-period confounds discussed in this article are important to resolve in a nursing study and when the confounds do not directly relate to the clinical or theoretical merit of a study.

Aged↗
PubMed1988

Gonadal steroid modulation of basal and vasoactive intestinal polypeptide-stimulated prolactin release by turkey anterior pituitary cells.

Porcine vasoactive intestinal polypeptide (VIP; 10(-9) to 10(-7) M) was a potent stimulator of prolactin (PRL) release by anterior pituitary cells from immature and laying turkey hens. Basal and VIP-induced PRL release of cells from laying hens were diminished (P less than 0.05) when the cells were cultured for 48 hr in the presence of charcoal-stripped laying hen serum, but not when the cells were cultured in the presence of whole laying hen serum. This change in VIP-induced PRL release was not evident when cells were derived from immature hens. Basal PRL release by cells from laying hens was not altered by the presence of estradiol (E2; 10(-12) to 10(-5) M), although such release was generally enhanced in cultures of cells from immature hens containing E2. The presence of E2 enhanced (P less than 0.05) the magnitude of the VIP-induced PRL release by cultures of cells from laying hens and diminished (P less than 0.05) the magnitude of this release in cultures of cells from immature hens. Cells from immature and laying hens exposed to progesterone (P4; 10(-5) M) for 96 hr exhibited enhanced basal PRL release, though lower P4 concentrations had no effect. Utilizing cells from laying hens, P4 exposure for 24 hr resulted in diminished (P less than 0.05) VIP-induced PRL release, while P4 exposure for 96 hr resulted in markedly enhanced (P less than 0.05) VIP-induced PRL release. Basal PRL release was generally not altered by the presence of testosterone (T). The VIP-induced PRL release by cells derived from immature and laying hens was diminished (P less than 0.05) by the presence of T. Prolactin release in the turkey is likely modulated by gonadal steroids acting directly on the cells of the anterior pituitary.

Animals↗
PubMed1988

Nurses' attitudes toward conventional and automated vital signs measurement methods.

The acceptance and assimilation of new medical technologies into the health-care arena is a complex process involving financial, humanistic, and clinical considerations. This experimental research compared nurses' attitudes regarding the clinical acceptability of conventional methods of measuring vital signs with their attitudes toward a new, automated method, using the IVAC Model 4000 Vital-Check. Two studies were conducted, at different university-affiliated hospitals, involving different nursing-care-delivery models. The 102 nurses who participated in the studies generally favored the automated method with respect to provider convenience, patient acceptance, and the opportunity to simultaneously perform other nursing assessments. Conventional techniques were preferred for patients on isolation precautions and in some very specific clinical situations such as those requiring detection of abnormalities in the heart rhythm. Interviews of patients were also conducted at both sites and their comments supplemented and supported the quantitative findings for the nurses. Patients seemed to adapt very well to the new technology. They were particularly interested in being better able to monitor their own measurements with the automated process.

Attitude of Health Personnel↗
PubMed1987

Gonadal steroid-mediated alteration of luteinizing hormone secretion by anterior pituitary cells of young turkeys.

The magnitude of luteinizing hormone (LH) release during a 3-hr test incubation was diminished (P less than 0.05) when anterior pituitary cells from young turkeys were cultured for 24 to 120 hr. This trend was evident with basal LH release and with LH release induced by luteinizing hormone-releasing hormone (LH-RH) or hypothalamic extract. Anterior pituitary cells were cultured with various concentrations (10(-14) to 10(-6) M) of estradiol (E2), progesterone (P4), or testosterone (T) for 24 hr and then exposed to LH-RH or control medium for 3 hr, still in the presence of steroids. Basal LH release was potentiated (P less than 0.05) when cells were cultured with 10(-8) or 10(-6) M T, but not with E2 or P4. When cells were cultured with E2, LH release in the presence of 10(-8) M LH-RH was enhanced (P less than 0.05) in a dose-dependent fashion. LH-RH mediated LH release was also enhanced (P less than 0.05) when cells were cultured with 10(-8) M P4 or 10(-6) M T. Gonadal steroids can act directly on the anterior pituitary of the young domestic turkey to modulate LH release, with T enhancing basal LH release and E2 potentiating LH-RH-mediated LH release.

Animals↗
PubMed1986

Methodological issues in the measurement of children's pain.

This paper focuses on some of the major issues surrounding the measurement of children's pain, particularly as they relate to problems of definition, level of measurement, dimensionality, reliability, and validity. The authors briefly describe some of the tools used with children and point out some of the problems that have resulted from the lack of well-tested, thoroughly validated instruments for children. As a common experience of hospitalized children, pediatric pain is creating concern within the health care community. The authors recommend that more attention be paid to the measurement issues surrounding this clinical phenomenon.

Child↗
PubMed1985

The augmentation of soft tissue with injectable collagen.

Clinical experience has demonstrated the value of injectable collagen in treating small soft-tissue defects. Among the lesions that respond best to injectable collagen therapy are nasolabial and glabellar lines as well as areas of atrophy and soft scars. This material is a useful adjunct to surgical procedures and can correct contour irregularities that may follow rhinoplasty or rhytidectomy. The safety of injectable collagen has also been well demonstrated. The nature and incidence of treatment reactions (less than 3 per cent) remains unchanged since the close of clinical trials. Reactions have been localized, and although some have been cosmetically undesirable, none has been health-threatening. All ultimately resolve without therapeutic intervention. Immunologic studies have confirmed the benign nature and specificity of reactions to injectable collagen. The importance of proper injection technique cannot be overstated. Immediately upon injection, tissue blanching followed by whealing and overcorrection should be evident. These indicate the desired superficial placement of the material. The overcorrection helps to compensate for the loss of carrier saline, and it quickly dissipates. When properly injected, injectable collagen can be used safely and effectively to correct an array of soft-tissue contour irregularities.

Antigens↗
PubMed1977

Pathologic scar formation. Morphologic and biochemical correlates.

Morphologic and biochemical analyses were performed to compare normal skin and mature scars to hypertrophic scar and keloid. Correlation of morphologic findings with biochemical profiles of the skin and scar samples proved feasible and enlightening. Scanning electron microscopy (SEM) was used to characterize the architectural arrangement of collagen fibers in skin and scars. Cultured fibroblasts from each specimen were also examined with the SEM. A biochemical profile of each tissue specimen was constructed, characterizing the collagen component of the specimen by sequential molecular sieve and ion exchange chromatography to determine a) the degree of intermolecular crosslinking, b) amino acid analysis, and c) levels of lysyl oxidase activity. Results indicate that collagen fibers and fiber bundles display a decreasing level of organization as the clinical degree of scar abnormality increases, and this structural gradient correlates with the gradient of intermolecular crosslinking in the same tissue--normal skin and mature scar being highly crosslinked, hypertrophic and keloid successively less so. Surprisingly, the level of the crosslinking enzyme lysyl oxidase is normal or elevated in hypertrophic scar and keloid despite the relative lack of crosslinking. Amino acid content was uniform for all specimens. Scanning electron microscopy examination of cultured fibroblasts from the tissue specimens demonstrated three phenotypically distinctive fibroblasts whose numerical and volumetric proportions correlated with the tissue of origin.

Amino Acids↗
PubMed1977

Injectable collagen for soft tissue augmentation.

Collagen from allogenic and xenogeneic sources has been made soluble by controlled proteolytic digestion. The monomeric, telopeptide-poor collagen so prepared forms a cohesive mass when warmed to body temperature (upon injection), creating a structural basis for new soft connective tissue. We have treated 28 patients with human and/or bovine collagen injections for the correction of soft tissue contour defects, and we have followed them for 3 to 18 months. In most instances, there has been lasting and substantial correction of the defects treated. The complications have been few and transient.

Acne Keloid↗
PubMedDate not supplied

Validity, reliability, and neither.

Some studies of measuring instruments are validity studies. Others are reliability studies. Still others, such as the investigation of the stability of a construct and the correlation between the scores on two different levels of the same test, are neither. Authors of test manuals and of journal articles dealing with certain tests should label them accordingly as substantive studies, not methodological investigations.

Humans↗
PubMedDate not supplied

Sex, age, height, and weight as predictors of selected physiologic outcomes.

The purpose of this study was to determine the extent to which sex, age, height, and weight predict selected physiologic outcomes, namely, forced expiratory volume in one second (FEV1), hemoglobin concentration, food intake, serum glucose concentration, total serum cholesterol concentration, and cancer-related weight change. Secondary analysis was performed on four datasets with sample sizes ranging from 60 to 8,489. FEV1 (R2 = .56), hemoglobin (R2 = .40), food intake (R2 = .25), glucose (R2 = .24), cholesterol (R2 = .21 and .15), and cancer-related weight change (R2 = .16 and .06) were predictable to varying extents. Moreover, the use of sex, age, height, and weight as covariates and in sample size determination was shown to be relevant when testing the effects of interventions or other variables on these physiologic outcomes.

Adolescent↗