Physician-patient-companion communication and decision-making: a systematic review of triadic medical consultations.

OBJECTIVE: To systematically review quantitative and qualitative studies exploring physician-adult patient-adult companion (triadic) communication and/or decision-making within all medical encounters. METHODS: Studies were identified via database searches and reference lists. One author assessed eligibility of studies, verified by two co-authors. Data were extracted by one author and cross-checked for accuracy. Two authors assessed the quality of included articles using standardized criteria. RESULTS: Of the 8409 titles identified, 52 studies were included. Summary statements and tables were developed for each of five identified themes. Results indicated companions regularly attended consultations, were frequently perceived as helpful, and assumed a variety of roles. However, their involvement often raised challenges. Patients with increased need were more often accompanied. Some companion behaviours were felt to be more helpful (e.g. informational support) and less helpful (e.g. dominating/demanding behaviours), and preferences for involvement varied widely. CONCLUSION: Triadic communication in medical encounters can be helpful but challenging. Based on analysis of included studies, preliminary strategies for health professionals are proposed. PRACTICE IMPLICATIONS: Preliminary strategies for health professionals include (i) encourage/involve companions, (ii) highlight helpful companion behaviours, (iii) clarify and agree upon role preferences of patient/companions. Future studies should develop and evaluate specific strategies for optimizing triadic consultations.

Comparative spontaneous Raman spectroscopy of crystals for Raman lasers.

A comparison of the spectroscopic parameters of Raman-active vibronic modes in various crystalline materials with a view to the use of these crystals for stimulated Raman scattering (SRS) is presented. It includes data on the Raman frequency shift, linewidth, integral, and peak Raman scattering cross sections. For steady-state SRS the highest Raman gain coefficient has been proved to be in barium nitrate and sodium nitrate crystals; for transient SRS it is expected to be in lithium niobate and tungstate crystals. Barium tungstate and strontium tungstate are proposed as new highly efficient Raman materials for both SRS cases.

Mechanisms of biliary stone fragmentation using the Ho:YAG laser.

We have investigated the fragmentation of gallstones using the pulsed Ho:YAG laser, comparing it to lithotripsy using the visible pulsed-dye laser. We find that the physical mechanisms of stone fragmentation appear to be quite different in the two cases. Using high-speed photography, measurement of acoustic transients, time-resolved optical emission spectroscopy, and direct microscopic observation, we have analyzed the interaction of the Ho:YAG laser with both water and gallstones. We propose a new model in which fragmentation begins with absorption of the laser light by the stone surface. This is followed by melting and ejection of stone material, which is then swept away by the vapor bubble formed by the absorption of the Ho:YAG laser light by water. This model is in excellent agreement with our experimental observations, and differs substantially from the model developed by Teng et al. for laser lithotripsy using the visible pulsed-dye laser.

Comparison of holmium and flashlamp pumped dye lasers for use in lithotripsy of biliary calculi.

The characteristics of laser lithotripsy of biliary calculi are compared for a flashlamp pumped dye laser (lambda = 640 nm) and a Cr:Tm:Ho-YAG laser (lambda = 2.1 microns). Data on fragmentation efficiency with respect to laser power and pulse repetition rate are presented for different types of stones. It is shown that both lasers can produce effective stone fragmentation. The laser power required for efficient fragmentation characteristics is significantly less for the visible wavelength laser. However, the problems associated with damage to the fiber tips of the delivery system during operation were found to be less with the near infrared wavelength. The laser power for efficient fragmentation with the dye laser varies significantly for different types of stones while the power for efficient fragmentation with the holmium laser is the same for all stones.

Pump wavelength tuning of a near-infrared optical parametric oscillator.

Optical parametric conversion in a potassium titanyl phosphate crystal with a tunable alexandrite laser was investigated as a function of pump wavelengths in the 700-800-nm region. Threshold energies and slope efficiencies for a doubly resonant oscillator configuration were measured for pump wavelengths of 744, 766, and 780 nm. Phase-matching conditions and a theoretical analysis using Sellmeier's equations provide good agreement with experimentally measured values of signal and idler wavelengths as a function of the pump wavelengths.

Lase-induced grating measurements of energy migration in Tm,Ho:YAG.

We report what is to our knowledge the first direct measurement of spatial energy migration among the Tm(3+) ions in a Tm,Ho:YAG crystal at room temperature. Four-wave mixing techniques were used to establish and probe transient laser-induced population gratings in the Tm(3+) ions. The grating decay rate was measured as a function of the grating spacing. The results show the presence of spatial energy migration among the Tm(3+) ions, and the diffusion coefficient of this process was measured to be 4 x 10(-7) cm(2) s(-1) for a sample containing 8.3 x 10(20) cm(-3) Tm(3+) ions.

Dispersion effects in four-wave mixing measurements of ions in solids.

We have performed nondegenerate four-wave mixing measurements on Cr(3+) ions in three crystals: BeAl(2)O(4), Gd(3)Sc(2)Ga(3)O(12), and LaMgAl(11)O(19). Two laser beams of the same frequency were used to resonantly pump one of the absorption bands of Cr(3+), and probe beams with three different wavelengths ranging from 442 to 1064 nm were used to generate a signal from the laser-induced population grating. The observed four-wave mixing signal strength was found to increase as the wavelength of the probe beam was decreased. A model was utilized to explain these results based on the change in polarizability of the Cr(3+) ions when they are in the metastable state versus the ground state, and it was found that the dispersion effects can be described by a single-oscillator model with the lowest-energy charge-transfer transition of Cr(3+) making the dominant contribution to the signal.

Optical applications of laser-induced gratings in Eu doped glasses.

Laser-induced changes in the refractive index are used to create superimposed transient population gratings and permanent structural gratings in Eu(3+) doped silicate and phosphate glasses. Potential uses for these laser-induced gratings (LIGs) are investigated. First, the structural gratings are shown to be permanent at room temperature and their use as a holographic storage medium is discussed. Second, a permanent LIG of this type is used to demultiplex multifrequency laser beams, demonstrating its use as a tunable line filter. Third, the transient LIG is used to modulate the amplitude of a laser beam which is passed through the sample and scatters off the permanent LIG. This results in information being transferred from one beam to another beam. It was found that thermal lensing plays an important role in the formation of this type of permanent LIG and a procedure for determining the tilt angle of the fringes of the LIG is discussed.

Index-of-refraction change in optically pumped solid-state laser materials.

Degenerate four-wave mixing measurements were made on several Nd(3+)-doped laser materials by resonantly pumping the Nd(3+) ions. The dominant contribution to the signal under these conditions is associated with the difference in polarizabilities of the Nd(3+) ions in the metastable state versus the ground state. Absolute measurements of the signal strengths imply a laser-induced polarizability change of the order of 0.01-0.05 A(3). The results indicate that, for the case of a single-shot laser amplifier system, the beam distortion induced by this population induced change in the refractive index is comparable with the distortion arising from thermal effects.

Faculty and house staff members as role models.

In the fall of 1986 approximately 100 faculty members, community physicians, house staff members, and students associated with Indiana University School of Medicine participated in a conference on "Teachers as Role Models: The Impact on the Learning Process." Small-group discussions allowed the participants to define and discuss the impact of role-modeling in medical education. It was anticipated by the organizers that after the conference the participants would be more cognizant of their influence as role models and would be motivated to become better role models and support good role-modeling. A synopsis of the conference indicates that the participants identified both the positive and negative impact of role-modeling and concluded that medical educational programs should use positive role-modeling as a teaching tool to instill within students the desire to gain new knowledge and to apply that knowledge as medical professionals.

Evaluation of materials for tunable vibronic lasers.

A comparison is made of the use of three techniques for determining the effects of stimulated emission on the spectra of solid-statevibronic laser materials: peak single-pass gain, fluorescence band narrowing, and lifetime shortening. Each of these was used to obtain the pump energy density and population inversion at threshold, the stimulated emission cross section, and the gain coefficient for two potential vibronic laser materials. The difficulty and accuracy of each technique is discussed. Lifetime shortening is the easiest experimental measurement to make. These results were analyzed by using numerical techniques to solve the coupled set of rate equations describing the concentration of photons and population of excited states of ions in an optically pumped material under delta-function pulsed excitation. The solutions predict an effective shortening of the fluorescence lifetime at high excitation levels with a distinct threshold where stimulated emission processes become important. The observed band narrowing for the same type of pumping conditions is shown to be consistent with the theoretical predictions of the model developed by McCumber.

Identification of Gln8-GnRH and His5,Trp7,Tyr8-GnRH in the hypothalamus and extrahypothalamic brain of the ostrich (Struthio camelus).

Gonadotropin-releasing hormone (GnRH) molecular forms were studied in extracts of ostrich hypothalamus and extrahypothalamic brain using high performance liquid chromatography, radioimmunoassay with region-specific antisera and assessment of luteinizing hormone (LH)-releasing activity using chicken dispersed pituitary cells. Two molecular forms of GnRH with chromatographic, immunological and biological properties identical to those of Gln8-GnRH and His5,Trp7,Tyr8-GnRH were demonstrated in both the hypothalamic and extrahypothalamic brain extracts. A greater proportion of His5,Trp7,Tyr8-GnRH was present in the hypothalamus than in extrahypothalamic brain. It is likely that these two forms of GnRH are present in all bird species, since the chicken and the ostrich have evolved separately.

Identification of diverse molecular forms of GnRH in reptile brain.

Gonadotropin-releasing hormone (GnRH) molecular forms in the brains of three reptiles, Alligator mississippiensis (alligator), Calcides ocellatus tiligugu (skink) and Podarcis s. sicula (lizard) were characterized by high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera, and by assessment of luteinizing (LH)-releasing activity in chicken dispersed pituitary cells. In alligator brain two GnRHs had identical properties to the two known forms of chicken hypothalamic GnRH (Gln8-GnRH and His5,Trp7,Tyr8-GnRH) in their elution on two reverse phase HPLC systems, cross-reaction with region-specific GnRH antisera, and ability to release LH. In skink brain, one immunoreactive and bioactive GnRH form, which eluted in the same position as His5,Trp7,Tyr8-GnRH on reverse phase HPLC, was identified. Three bioactive and immunoreactive GnRHs were detected in lizard brain. One form had similar properties to salmon brain GnRH (Trp7,Leu8-GnRH). The other two GnRH-like peptides are novel forms. One of these forms eluted in the same position as Gln8-GnRH on HPLC but had different immunological properties, while the third form was a rather hydrophobic species which appeared to be modified in the middle region of the molecule.

Diverse molecular forms of gonadotropin-releasing hormone in an elasmobranch and a teleost fish.

Immunoreactive and biologically active gonadotropin-releasing hormones (GnRHs) in dogfish (Poroderma africanum) and teleost (Coris julis) brain extracts were studied by high-performance liquid chromatography (HPLC), radioimmunoassay with region-specific antisera, and assessment of luteinizing hormone (LH)-releasing activity in a chicken dispersed pituitary cell bioassay. In dogfish brain extract, seven GnRH molecular forms with LH-releasing activity were demonstrated. Three of these forms coeluted with synthetic mammalian GnRH; His5,Trp7,Tyr8-GnRH; and Trp7,Leu8-GnRH on HPLC. The peaks coincident with His5,Trp7,Tyr8-GnRH and Trp7,Leu8-GnRH had immunological and biological properties identical to those of the synthetic peptides. However, the molecular form coeluting with mammalian GnRH had immunological and biological properties different from those of mammalian GnRH and is thus a novel molecular variant of GnRH. The four remaining forms are also novel GnRHs or structurally unrelated peptides with LH-releasing activity. Dogfish systemic blood contained immunoreactive GnRH. In teleost brain extract, three biologically active GnRH forms with LH-releasing activity were present. The major peak of GnRH immunoreactivity coeluted with Trp7,Leu8-GnRH, and a second immunoreactive form coeluted with His5,Trp7,Tyr8-GnRH. The third biologically active peak is a novel, early-eluting molecular variant of GnRH or a structurally unrelated peptide with LH-releasing activity.

Observation of erasable holographic gratings at room temperature in Eu(3+)-doped glasses.

The characteristics of four-wave mixing signals were studied in Eu(3+)-doped glasses. When the Eu(3+) ions were resonantly excited, two types of laser-induced grating were formed: a transient population grating associated with the excited Eu(3+) ions and a holographic grating, which was permanent at room temperature but could be erased either thermally or optically.

[Trp7,Leu8]LH-RH in reptilian brain.

Luteinizing hormone-releasing hormone (LH-RH) immunoreactive peptides in acetic acid extracts of lizard (Cordylis nigra) brain were studied by high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera. Four different LH-RH immunoreactive peptides were detected. The major form co-eluted with salmon brain LH-RH, [Trp7,Leu8]LH-RH, in a cation exchange and three reverse phase HPLC systems which were specifically designed to separate a range of LH-RH analogues. The interaction of this major LH-RH immunoreactive peptide with a number of antisera directed against different regions of mammalian, chicken and salmon LH-RH was similar to the relative interaction of [Trp7,Leu8]LH-RH with these antisera. These data strongly indicate that the major form of lizard brain LH-RH is identical to salmon brain LH-RH [( Trp7,Leu8]LH-RH). The three additional molecular forms of immunoreactive LH-RH in lizard brain appear to differ from mammalian LH-RH in the middle to C-terminal region of the molecule.

Stimulated emission and tunable gain from Rh(2+) ions in RbCaF(3) crystals.

Stimulated emission was detected in RbCaF(3):Rh(2+) crystals through the observation of power-dependent shortening of the fluorescence lifetime and narrowing of the emission band with a distinct threshold. In addition, single-pass gain was observed to be tunable between about 700 and 720 nm.