Bereavement and remarriage for older adults

The purpose of this study was to assess differences in bereavement outcomes between surviving spouses aged 50 and over who remarried within 4-5 years and those who did not. Fifteen bereaved respondents out of 192 in a longitudinal prospective study who later remarried were compared with 15 other matched nonremarried respondents. Analyses of sociodemographic data, standardized measures of depression, life-satisfaction, resolution of grief, and self-perceived ratings of coping, stress, self-esteem, health and social support were performed with correlated t-tests. Statistically significant differences indicated that over time, the remarried subjects displayed more positive outcomes.     

An Inbred Epilepsy-Prone Substrain of BALB/c Mice Shows Absence of the Corpus Callosum, an Abnormal Projection to the Basal Forebrain, and Bilateral Projections to the Thalamus

BALB/c mice lack a corpus callosum in about 11% of the population.Two inbred substrains of BALB/c mice, epilepsy-prone (EP) andepilepsy-resistant (ER), have been examined to determine whetherthese substrains differ in regard to corpus callosum morphology.Further, this study addressed the issue of whether misroutedcortical axons form an aberrant pathway instead of the corpuscallosum. Initial studies that examined fresh brain tissue ofadult animals revealed normal corpora callosa in all ER micebut deficient or absent corpora callosa in all EP mice. Subsequently,Dil crystals were placed in the motor cortices of aldehyde-fixedbrains of 2-week-old animals to investigate cortical projectionsin both inbred substrains of mice. Fluorescent microscopy revealedthat all of the ER animals had normal corpora callosa, whereasall EP animals exhibited either reduced corpora callosa (partiallycallosal) or an absence (acallosal) of this structure. Bothacallosal and partially callosal EP mice displayed an extensive,aberrant projection to the basal forebrain as well as bilateralprojections to midline and intralaminar thalamic nuclei. Thefibers projecting to the basal forebrain arose from the cortex,coursed toward the midline before turning ventrally along themidline, and appeared to terminate in the medial septal nucleusand the nucleus of the diagonal band. ER animals lacked thisaberrant cortical projection to the basal forebrain. Electronmicroscopic results obtained from EP mice indicated that labeledaxons in this aberrant pathway formed axosomatic, axodendritic,and axospinous synapses with the neurons in the medial septal/diagonalband complex. The function of the aberrant projection to thebasal forebrain remains unknown but it may provide an abnormalexcitatory input to a region that provides cholinergic and GABAergicinput to the cerebral cortex and hippocampus. The additionalprojections to midline and contralateral intralaminar thalamicnuclei in EP mice may function to intensify the synchronizationof bilateral discharges.     

Comparison of ultrasonic cleaning schemes: a pilot study.

OBJECTIVE: Ultrasonic cleaning is an effective method for cleaning dental instruments prior to sterilisation. However, there are few studies that directly compare precleaning and ultrasonic cleaning solutions. This study evaluated the efficacy of different ultrasonic cleaning schemes. METHOD AND MATERIALS: Twenty representative dental instruments, five of which were soiled with a mixture of blood and hydroxyapatite, were used in a series of cleaning runs. Cleaning employed a presoaking agent, ultrasonic cleaning, or a combination of both. Two presoaking agents (Non-ionic Ultrasonic Cleaning Solution and ProEZ Foaming Enzymatic Spray) plus five ultrasonic cleaners (UltraDose, General Purpose Cleaner, Co-enzyme Concentrate, Enzol Enzymatic Detergent, and Non-ionic Ultrasonic Cleaning Solution) were compared, with tap water serving as a control. There were two cleaning times: seven and 15 minutes. After rinsing, the working ends of the instruments underwent scrubbing for 20 seconds using a dental polishing brush held in a haemostat. After scrubbing, the brush and instrument were placed in a tube containing sterile saline. Vortexing of the tube lasted 30 seconds. Testing for the post-cleaning presence of blood involved Hemastix dipsticks. These sticks measure minute amounts of blood in urine and can detect as few as 35 red blood cells per ml. Comparisons of colour change were made to a standard scale followed by assignment of numeric values. RESULTS: Tap water was the poorest cleaning solution, while UltraDose was the most effective. Blood removal improved when cleaning time was increased from seven to 15 minutes. The combined effect of a presoak immersion followed by ultrasonic cleaning was the most effective cleaning scheme overall. Cleaning by either ultrasound or presoaking only was less effective. Some instruments were more difficult to clean than others. CONCLUSION: Within the constraints of the small number of test runs performed, it was concluded that application of a presoak agent before ultrasonic cleaning produced the most effective instrument-cleaning regimen.     

Asymptomatic metachronous metastatic renal cell adenocarcinoma to the gallbladder

Summary A case of asymptomatic metachronous metastatic unilateral renal cell adenocarcinoma to the gallbladder detected five years after resection of the primary renal neoplasm is reported here. The lesion was diagnosed by contrast enhancement of a gallbladder mass on abdominal computerized tomography scan and by color Doppler sonographic study of the gallbladder, both of which demonstrated the vascular supply to the intraluminal gallbladder mass. The biological behavior of renal cell adenocarcinoma is reviewed. Guidelines for the evaluation of intraluminal gallbladder masses are suggested.     

Reperfused myocardial infarctions on T1- and susceptibility-enhanced MRI: Evidence for loss of compartmentalization of contrast media

The purpose of this study was to characterize the contrast caused by a susceptibility MRI contrast agents, on spin echo T₂-weighted imaging of reperfused myocardial infarction. Our interest in this model focused on the expected requirement that such agents be compartmentalized in the tissue to cause signal loss on spin echo images, a condition which may not be present in reperfused infarcted myocardium. Accordingly, nine rats were subjected to 2 h of left coronary artery occlusion followed by 3 ± 0.5 h of reperfusion prior to administration of contrast media. Three sets of MR images were acquired: (a) baseline axial images at the midventricle, both T₁-weighted (TR/TE = 300/20) and T₂-weighted (TR/TE = 1500/60); (b) T₁-weighted images after administering a T₁-enhancing agent, Gd-DTPA-BMA (0.2 mmol/kg), to document that contrast media is delivered to the reperfused infarction; and (c) T₂-weighted images after administering the susceptibility agent, Dy-DTPA-BMA (1.0 mmol/kg). Gadolinium-enhanced T₁ images depicted reperfused infarction as regions with greatly enhanced signal intensity compared with unin-farcted myocardium, indicating that contrast agent was delivered to the infarcted zone. Dysprosium-enhanced T₁ images depicted the injury as a region of persistent signal intensity relative to depletion of signal in normal myocardium, consistent with failure of the contrast agent to cause signal loss. Similar infarction sizes were observed for unenhanced T₂-weighted images (33 ± 5%), gadolinium-enhanced T₁ weighted images (36 ± 5%) and postmortem staining (30 ± 6%); strong correlations (r > 0.9) were noted in comparisons of these data. Dysprosium-enhanced images exhibited a smaller region of differential signal presumed to be infarction (20 ± 5%, P < 0.05) and weak correlations (r < 0.75) with the other measurements. We conclude that the smaller infarction depicted on dysprosium-enhanced images is a subregion of the true infarction in which myocardial necrosis is sufficiently advanced that the agent is homogeneously distributed throughout all tissue compartments, preventing T₂*-dependent phase loss on spin echo images.     

Use of long catheters for multipatient anesthetic monitoring at high respiratory frequencies

Anesthetic gases from several patients can be monitored simultaneously with a centrally located mass spectrometer. Such monitoring requires catheters from patient to spectrometer that are several meters long. Scamman (J Clin Monit 1988;4:227–229) found that when the respiratory frequency is high, as with infants, the CO₂ signal from the patient is unacceptably distorted during passage down the catheter. This is due to Taylor dispersion of the input signal. An outline of the theory of Taylor dispersion is given. The equations describe the interaction between the velocity distribution (which, in laminar flow, is parabolic) and the radial diffusion of CO₂. This interaction keeps a tracer signal together in a pulse, as it moves down the tube with themean velocity, spreading somewhat as it proceeds. How much does an initially sharp signal become blurred? The spread of such a signal when it reaches the detector, measured in time, can be expressed in various ways. Measurement is complicated, however, by the fact that the gas pressure may fall by as much as a factor of 10 along the line. The resultant expansion and acceleration of the gas cannot be ignored. A full treatment of this complication is given elsewhere, but the following simple equation is described: {ie237-1} Typically, the spread time is up to a quarter of a second for catheters of 50 m, such as used by Scamman. This is comparable with the period of CO₂ rise and fall for infants and explains the serious distortion in wave form that Scamman found. Some distortion can be eliminated by reducing R to 0.1 or less, but the extent of this improvement is small. Ideally, for fast-breathing patients, the catheter length should be reduced to 20 m or less, if possible.