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PubMedDate not supplied

[Basic principles and characteristics of transcutaneous "reflective" oximetry].

The papers considers the main methods of mathematical description of light-biological tissue interactions in the context of problems of transcutaneous reflective oximetry. Provides a review of the most significant studies which have been recently performed in this field. By using them as an example, the paper analyzes the most serious problems arising in designing reflective oximeters and the main ways to solve them. The paper also discusses the advantages of the reflective oximeter and prospects for their development.

Blood Gas Monitoring, Transcutaneous↗

PubMedDate not supplied

The benefits of a reflective model of nursing.

The concept of reflective practice is proving popular among practising nurses. This paper describes a way of using reflection in practice. It also describes how reflective principles were used to underpin the development of a model to guide nurses' work. The difference between this approach and the traditional use of theoretical models is outlined and its value for guiding practice is discussed. A second article next month will look at the model in practice in more detail.

Humans↗

PubMed1997

Reflection of an experience!

Reflection has become an everyday word in the nursing press and literature, but what does it mean exactly to us as nurse practitioners, and how can we actually use it to good effect in our everyday working practice? Much of the literature available on reflection is both complex and abstract. The aims of this article are to give an insight into the topic through reviewing the literature and then presenting a personal example of 'reflection of an experience'.

Humans↗

PubMed1997

Nurses' perceptions of reflective practice.

Reflective practice has become an accepted part of nursing development. The authors of this article asked clinicians and managers in their trust how they thought reflective practice may be enhanced. The study has enabled the trust to develop reflective practice in a number of ways which may benefit clinicians, managers and patients.

Attitude of Health Personnel↗

PubMed1976

The right pleuromediastinal reflection in children.

The authors review the anatomy of the pleural reflection of the right lung against the middle mediastinum in childhood. In 505 consecutive normal frontal radiographs of children, from birth to sixteen years, this pleural reflection (also known as the pleuro-esophageal line) was visible in 83%. The entire reflection from thoracic inlet to diaphragm was clearly seen in 13%, chiefly in upright, deep-inspiration, well penetrated radiographs. It is a radiographic landmark in the middle mediastinum, particularly well seen in childhood, and its use in assessment of mass lesions, cardiomegaly and lung collapse is described.

Adolescent↗

PubMed1998

Determination of age in dogs and cats by use of changes in lens reflections and transparency.

OBJECTIVE: To develop and test a noninvasive technique for determining age in dogs and cats on the basis of changes in lens reflections and transparency. ANIMALS: 85 dogs representing 5 breeds and 73 domestic shorthair cats. PROCEDURE: While examining dilated eyes in a darkened room, using a penlight, 2 experienced examiners who were blinded to actual age of animals individually measured the diameter of reflections from the anterior (La) and posterior (Lb) surfaces of the lens and scored lens transparency (Ltr) from 1 (clear) to 5 (severe opacity). Models were developed to predict age on the basis of these measurements. RESULTS: Aging models developed for dogs and cats were as follows: Age(dogs) = 2.197 - 0.070 x (La) + 1.361 x (Lb) + 1.193 x (Ltr) and Age(cats) = 1.988 + 1.024 x (La) + 2.220 x (Lb) + 1.019 x (Ltr), where age was expressed in years, and La and Lb were in millimeters. All variables, except La in dogs, contributed significantly to accuracy of the models. Correlation between predicted and actual ages, as measured by Pearson's product-moment correlation coefficient, was significant in both species (P < 0.0001). Significant differences were not found between examiners or between the first and second evaluations by the same examiner. CONCLUSIONS AND CLINICAL RELEVANCE: A noninvasive technique based on evaluation of lens reflections and transparency can provide clinically useful predictions of age in mature dogs and cats. This technique could be an important tool for veterinarians or humane shelters in determining differential diagnoses and assessing longevity and adoptability of mature animals of unknown age.

Aging↗

PubMed1995

[Evaluation of ultraviolet radiation reflectance for human skin].

In a group of 20 males aged 19-20 years ultraviolet radiation reflectance of different wavelength (250-400 nm) from skin surface was measured. It was found that the reflectance increased monotonically with the decrease of wavelength. The reflectance values were compared with the coefficient of relative spectral biological effectiveness and significance of both values for evaluation of human exposure to ultraviolet radiation was discussed.

Adult↗

PubMed1998

Effect of flow on hydraulic conductivity and reflection coefficient of rabbit mesentery.

OBJECTIVE: To measure the hydraulic conductivity and reflection coefficient for albumin, as defined by the Starling equation, in rabbit mesentery. METHODS: A section of rabbit mesentery was fixed between two chambers filled with lactated Ringer solution. Flow (Q) of Ringer solution was measured across the mesentery at driving pressures (delta P) between 1 and 6 cm H2O. Hydraulic conductivity was proportional to the slope of the Q-delta P curve. At constant delta P (approximately -2, -4, or -6 cm H2O), flow was measured at three different albumin concentration differences (0.5, 1, and 1.5 g/dl). Unstirred layer effects were minimized by magnetic stirrers. Reflection coefficient was the negative of the slope of the Q-delta pi curve divided by the slope of the Q-delta P curve, where delta pi was the albumin osmotic pressure difference. Hydraulic conductivity was measured before and after testicular hyaluronidase was added to the Ringer solution. RESULTS: There was no significant difference in conductivity per unit area (Lp) for the three different driving pressures. Hyaluronidase increased hydraulic conductivity significantly (p < 0.01) by 72 +/- 56%, indicating that hyaluronan and other glycosaminoglycans contributed to tissue fluid resistance. Reflection coefficient (sigma) increased from 0.02 to 0.14 as flow increased eightfold. CONCLUSIONS: The results suggest that the mesentery tissue provides little restriction to the passage of albumin. The increase in conductivity in the presence of hyaluronidase indicates that tissue hyaluronan and other glycosaminoglycans provide fluid resistance to bulk flow.

Albumins↗

PubMedDate not supplied

Reflection on a patient receiving high frequency oscillatory therapy.

This reflection on practice is written by two members of a primary nurse team at the Chelsea and Westminster intensive care unit (ICU)/nursing development unit (NDU). Johns's (1993) tool for structured guided reflection was used to reflect on the care of an ICU patient given by her primary and associate nurse. The issues highlighted include: The importance of knowing your patient through a primary nursing approach. Collaboration between the primary nursing team and the anaesthetists. Negotiation between the patient, her family and the primary nursing team. Empowerment of the patient to express her view.

Aged↗

PubMed2026

Final-year nursing students' clinical practice experiences: a reflection study.

OBJECTIVES: This study aimed to explore the most impactful clinical practice experiences of final-year nursing students and the future-oriented actions developed in response to these experiences. METHODS: A retrospective descriptive qualitative design was used. Following reflection training in the internship practice course, 134 final-year nursing students were asked to describe the experience that affected them most during clinical practice. A total of 123 written reflections were analyzed using content analysis. RESULTS: Three themes emerged: near-miss events, incivility behaviors, and positive preceptoring roles. Negative experiences were mainly related to patients, relatives, and nurses and often led students to feel fear and inadequacy. Students reported action plans focused on effective communication, safe patient care, and becoming positive role models. CONCLUSIONS: These findings highlight the importance of supportive clinical learning environments and positive professional socialization during the transition from student to nurse. IMPLICATIONS FOR INTERNATIONAL AUDIENCE: Nursing students worldwide may encounter incivility and near-miss events during clinical practice, potentially adversely affecting their learning experiences and professional development.

Humans↗

PubMed1985

Circular polarizers enhance visibility of endothelium in specular reflection biomicroscopy.

A simple and inexpensive technique for enhancing the visibility of corneal endothelial cells in specular reflection biomicroscopy involves the insertion of a circular polarizer in front of the patient's eye, intersecting both the incident and reflected light beams. This filter significantly reduces the glare from the epithelium and enables more comfortable and clearer viewing of the endothelial cells.

Cornea↗

PubMed1989

Colorectal neodymium-YAG photoablative therapy. Comparing applications and complications on both sides of the peritoneal reflection.

Laser photoablative therapy has seen wide application in the esophagus, stomach, and rectum. Its use in the supraperitoneal colon has been less extensive because of fear of complications. One hundred fifteen patients who presented during a four-year period and underwent neodymium-YAG laser treatment on both sides of the peritoneal reflection (rectum, 47 patients; colon, 68 patients) were reviewed. The various lesions treated with laser therapy included 32 malignant tumors that presented with bleeding or obstruction, 44 large broad-based villous adenomas, six carcinoid tumors, and 33 patients with arteriovenous malformations or radiation proctitis who presented with acute hemorrhage or chronic blood loss. Overall treatment efficiency was 83% in the rectal group vs 87% in the colonic group. There was no significant difference in complication frequency or severity between the two groups, even though 45% of the colonic lesions were located in the thin-walled cecum. There was no laser-related mortality in this series. Laser photoablative therapy is safe and effective treatment for a wide variety of colorectal lesions. In experienced hands, it can be used on either side of the peritoneal reflection with equal efficiency and no increased risk of complications.

Adenoma↗

PubMed2003

Association of funding and conclusions in randomized drug trials: a reflection of treatment effect or adverse events?

CONTEXT: Previous studies indicate that industry-sponsored trials tend to draw proindustry conclusions. OBJECTIVE: To explore whether the association between funding and conclusions in randomized drug trials reflects treatment effects or adverse events. DESIGN: Observational study of 370 randomized drug trials included in meta-analyses from Cochrane reviews selected from the Cochrane Library, May 2001. From a random sample of 167 Cochrane reviews, 25 contained eligible meta-analyses (assessed a binary outcome; pooled at least 5 full-paper trials of which at least 1 reported adequate and 1 reported inadequate allocation concealment). The primary binary outcome from each meta-analysis was considered the primary outcome for all trials included in each meta-analysis. The association between funding and conclusions was analyzed by logistic regression with adjustment for treatment effect, adverse events, and additional confounding factors (methodological quality, control intervention, sample size, publication year, and place of publication). MAIN OUTCOME MEASURE: Conclusions in trials, classified into whether the experimental drug was recommended as the treatment of choice or not. RESULTS: The experimental drug was recommended as treatment of choice in 16% of trials funded by nonprofit organizations, 30% of trials not reporting funding, 35% of trials funded by both nonprofit and for-profit organizations, and 51% of trials funded by for-profit organizations (P<.001; chi2 test). Logistic regression analyses indicated that funding, treatment effect, and double blinding were the only significant predictors of conclusions. Adjusted analyses showed that trials funded by for-profit organizations were significantly more likely to recommend the experimental drug as treatment of choice (odds ratio, 5.3; 95% confidence interval, 2.0-14.4) compared with trials funded by nonprofit organizations. This association did not appear to reflect treatment effect or adverse events. CONCLUSIONS: Conclusions in trials funded by for-profit organizations may be more positive due to biased interpretation of trial results. Readers should carefully evaluate whether conclusions in randomized trials are supported by data.

Bias↗

PubMed2000

Reflection contrast microscopy (RCM): a forgotten technique?

Reflection contrast microscopy (RCM), which utilizes the optical phenomena caused by oblique epi-illumination in combination with a specific optical apparatus, provides an approach for exploring biological phenomena in greater detail. The lack of stray reflection makes it superior to other microscopes. It bridges light and electron microscopic capabilities by allowing the analysis of ultrathin sections beyond the usual light microscopic magnification. By using consecutive image analysis, quantitation can be achieved. The wide range of applications of RCM can be combined with most microscopical techniques, so extending the spectrum of information that can be gathered. Twenty-five years after the development of RCM, there is still scope for its application in modern cell biology.

Animals↗

PubMedDate not supplied

Binding of the soluble, truncated form of an Fc receptor (mouse Fc gamma RII) to membrane-bound IgG as measured by total internal reflection fluorescence microscopy.

Total internal reflection fluorescence microscopy has been used to investigate the binding of the soluble extracellular domain of mouse Fc gamma RII (sFc gamma RII) to an anti-trinitrophenyl monoclonal mouse IgG2b (GK14.1) specifically bound to substrate-supported planar membranes composed of dipalmitoylphosphatidylcholine (DPPC) and trinitrophenylaminocaproyldipalmitoylphosphatidylethanolamine (TNP-cap-DPPE). The equilibrium dissociation constants for sFc gamma RII at GK14.1-coated TNP-cap-DPPE/DPPC planar membranes containing 0.5-25 mol% TNP-cap-DPPE were approximately 1 microM. Total internal reflection with fluorescence photobleaching recovery was used to examine the dissociation kinetics. The fluorescence recovery curves were better described as a sum of two exponentials rather than by one exponential; the rates and fractional recoveries were approximately 1 s-1 (65%) and approximately 0.1 s-1 (35%). The similarity between the values of these equilibrium and kinetic parameters to those previously measured for the binding of IgG in solution to intact mouse Fc gamma RII reconstituted into planar membranes suggests that conformational changes which may occur when IgG is constrained to a membrane surface do not significantly affect the equilibrium or kinetics of IgG-mouse Fc gamma RII binding. The stoichiometry of sFc gamma RII-GK14.1 binding was 1:4, indicating that a significant fraction of the membrane-bound antibodies were not accessible for receptor binding. Possible mechanisms that might underlay the observed heterogeneity in sFc gamma RII-IgG binding kinetics are discussed.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2000

Time-lapse confocal reflection microscopy of collagen fibrillogenesis and extracellular matrix assembly in vitro.

The development of the next generation of biomaterials for restoration of tissues and organs (i.e., tissue engineering) requires a better understanding of the extracellular matrix (ECM) and its interaction with cells. Extracellular matrix is a macromolecular assembly of natural biopolymers including collagens, glycosaminoglycans (GAGs), proteoglycans (PGs), and glycoproteins. Interestingly, several ECM components have the ability to form three-dimensional (3D), supramolecular matrices (scaffolds) in vitro by a process of self-directed polymerization, "self-assembly". It has been shown previously that 3D matrices with distinct architectural and biological properties can be formed from either purified type I collagen or a complex mixture of interstitial ECM components derived from intestinal submucosa. Unfortunately, many of the imaging and analysis techniques available to study these matrices either are unable to provide insight into 3D preparations or demand efforts that are often prohibitory to observations of living, dynamic systems. This is the first report on the use of reflection imaging at rapid time intervals combined with laser-scanning confocal microscopy for analysis of structural properties and kinetics of collagen and ECM assembly in 3D. We compared time-lapse confocal reflection microscopy (TL-CRM) with a well-established spectrophotometric method for determining the self-assembly properties of both purified type I collagen and soluble interstitial ECM. While both TL-CRM and spectrophotometric techniques provided insight into the kinetics of the polymerization process, only TL-CRM allowed qualitative and quantitative evaluation of the structural parameters (e.g., fibril diameter) and 3D organization (e.g., fibril density) of component fibrils over time. Matrices formed from the complex mixture of soluble interstitial ECM components showed an increased rate of assembly, decreased opacity, decreased fibril diameter, and increased fibril density compared to that of purified type I collagen. These results suggested that the PG/GAG components of soluble interstitial ECM were affecting the polymerization of the component collagens. Therefore, the effects of purified and complex mixtures of PG/GAG components on the assembly properties of type I collagen and interstitial ECM were evaluated. The data confirmed that the presence of PG/GAG components altered the kinetics and the 3D fibril morphology of assembled matrices. In summary, TL-CRM was demonstrated to be a new and useful technique for analysis of the 3D assembly properties of collagen and other natural biopolymers which requires no specimen fixation and/or staining.

Animals↗

PubMed1979

The effectiveness of the psychodramatic double method, the reflection method, and lecturing in the training of empathy.

Studied the effectiveness of the psychodramatic Double method, the Reflection method, and the Lecture method in improving empathic ability. Sixty-four high school sophomores were assigned randomly to four groups of 16 Ss, 8 males and 8 females, each. Three groups received one of the three training methods and the fourth served as no-training control. The Ss' level of empathy, before and after the training, was measured by a modified version of the Accurate Empathic Scale. The results showed that all three training methods produced significant improvements compared with the control group. The effect of the Double method was significantly greater than that of the other two methods. The Reflection method ranked second, yet was not significantly better than the Lecture method. Females scored higher than males both before and after the training, but there was no significant sex and training method interaction effect.

Adolescent↗

PubMed2001

Low-level determination of polymorph composition in physical mixtures by near-infrared reflectance spectroscopy.

Near-infrared reflectance spectroscopy (NIRS) was employed to quantify sulfathiazole (STZ) forms I and III in binary physical mixtures in which one form was the dominant component. Physical mixtures of the polymorph pair were made by weight, ranging from 0 to 5% STZ form I mixed with STZ form III, and near-infrared spectra of the powder samples contained in glass vials were obtained over the wavelength region of 1100 to 2500 nm. A calibration plot was constructed by plotting STZ form I weight percent against a ratio of second-derivative values of log (1/R') (where R' is the relative reflectance) versus wavelength. The coefficients of determination, R(2), were > 0.9983 and standard errors were low for these calibration models. The instrument reproducibility, method error, and limits of detection (LOD) and quantification (LOQ) of the method were assessed. The LOD and LOQ were determined from the standard deviation of the response of the 0% analyte sample (0% STZ form I containing 100% STZ form III). The LOQ was subsequently validated with independently prepared samples. The results show that polymorphs can be quantified in binary physical mixtures in the 0.3% polymorph composition range. These studies indicate that NIRS is a precise and accurate quantitative tool for determination of polymorphs in the solid state, is comparable to other characterization techniques, and is more convenient to use than many other methods.

Calibration↗