The relationship of scoring systems and mortality in the surgical intensive care unit

To determine the relationship between severity of illness and mortality, therapeutic intervention score (TISS) and acute physiology score (APS) were determined on admission to the Surgical Intensive Care Unit (SICU). Patients were divided into survivors and nonsurvivors and differences were compared by chi-square analysis. The 1524 patients admitted to the SICU during a 12-month period had a mean TISS of 3.03 and a mean APS of 13. The average length of stay (LOS) was 3.75 days. Of the 1524 patients, 97 (6.4%) died. The number of nonsurvivors increased with higher TISS and APS scores (P less than 0.001). There were no deaths in the TISS Category 1 patients or in the APS 0-5 group. Mortality rates dramatically increased with APS greater than 20 (P less than 0.001). There were 1286 patients with APS less than 20, and 24 (2%) of these patients died, whereas 73 (31%) of 238 patients with APS greater than 20 died. Nonsurvivors had a mean TISS of 3.6, mean APS of 27, and LOS of 4.88 days, all of which totals were higher than the survivors' totals. In this study population, risk of death was one in three if the APS was greater than 20. These data indicate that TISS and APS scores are effective means of assessing mortality risk in SICU patients.     

Bridges and barriers to recovery: Clinical observations from an opiate recovery project

Clinical issues are described in opiate addicts attempting to taper off methadone maintenance, and techniques are suggested to help this patient population. The observations were generated in an experimental “Tapering Network” project, in which opiate addicts on methadone maintenance had the opportunity to receive individual and group counseling, relapse prevention training, self-help groups, and other services. Vignettes illustrate clinical problems with intimacy and social isolation, identity as a former addict, and a “post methadone syndrome” characterized by vulnerability, dramatic swings in mood, and disordered thinking for a period of up to six months after detoxification. To counteract these barriers to recovery, a program model is suggested that uses curricula available in the emerging literature on treatment of substance abuse. These techniques can provide bridges to recovery.     

Inconsistencies in paranoid functioning, premorbid adjustment, and chronicity: question of diagnostic criteria

Despite the widely held belief that paranoid behavior is associated with good premorbid adjustment, low chronicity, and high current functioning in psychiatric inpatients, inconsistencies in the literature suggest that supportive evidence may be an artifact of the measurement model commonly used to index paranoid status. In a sample of 497 nonorganic inpatients selected from 19 treatment units, paranoid behavior, when measured by a dimensional/cumulative model, was not found to indicate higher functioning and associated relationships, but simply to reflect a narrower class of problem behavior. Only when paranoid status was defined using a traditional model based on the predominance of the defining class of behavior did paranoid subjects demonstrate better premorbid adjustment, lower chronicity, and higher levels of functioning than nonparanoid subjects. Serious problems exist in the use of information obtained from traditional predominance/class models for either theoretical or practical purposes.     

Damage mechanics and load failure of fiber-reinforced composite fixed partial dentures

OBJECTIVES: Damage mechanics has been defined as the study of the initiation (initial failure) and accumulation of damage to and including rupture (final failure). This study was designed to evaluate the effect of increasing fiber-reinforced composite (FRC) substructure within a standardized fixed partial denture (FPD) model on the failure performance, in terms of damage mechanics. METHODS: The two FRC restorative systems, Targis/Vectris (TV) (Ivoclar Vivadent) and EverStick (ES) (Stick Tech with Gradia, GC Corp.), were used to restore the molar FPD model (1.5 mm axial and 2.0 mm occlusal reduction). Templates were used to standardize substructure designs with 0, 18, 43, and 66% cross-sectional FRC volume fraction (V(FRC)) of fiber substructure. Specimens (n = 5) were homogenized at 29 points and stored for 1 week at 37 degrees C in distilled water. Specimens were luted with calcium hydroxide, then statically loaded until failure. Initial failure (IF), final failure (FF) and the mode of failure were recorded. RESULTS: The lowest mean load to initial failure was 530 N (TV 18%) and the highest was 1208 N (ES 66%). Linear regression analysis calculated the Pearson's correlation coefficient (r) for the interactions between V(FRC) and IF (ES: r = 0.7879, TV: r = 0.6184), V(FRC) and FF (ES: r = 0.912, TV: r = 0.8152), and between IF and FF (ES: r = 0.892, TV: r = 0.7237). Unreinforced specimens universally fractured instantaneously. SIGNIFICANCE: The highest loads to initial and final failure were yielded by specimens with the highest cross-sectional V(FRC).     

1 alpha,25-dihydroxyvitamin D3-induced increments in hepatocyte cytosolic calcium and lysophosphatidylinositol: inhibition by pertussis toxin and 1 beta,25-dihydroxyvitamin D3

1 alpha,25-Dihydroxyvitamin D3 rapidly increases cytosolic calcium and alters membrane phospholipid metabolism in hepatocytes. To define the causal relationship between these events, we examined the effects of 1 alpha,25-dihydroxyvitamin D3 on 32P-labeled lysophosphatidylinositol levels and cytosolic calcium as affected by pertussis toxin and 1 beta,25-dihydroxyvitamin D3, the biologically inactive analog. 32P-labeled lysophosphatidylinositol was determined by two-dimensional thin-layer chromatography. Cytosolic calcium was measured in cells loaded with quin-2AM. Within 5 min, 1 alpha,25-dihydroxyvitamin D3 increased hepatocyte cytosolic calcium by 31% (p less than 0.05) and 32P-labeled lysophosphatidylinositol by 38% (p less than 0.05). Pertussis toxin inhibited the hormone-induced rise in cytosolic calcium but not the increase in 32P-labeled lysophosphatidylinositol. Exposure to exogenous lysophosphatidylinositol for 5 min increased cytosolic calcium by 40% (p less than 0.05), an effect that was also inhibited by pertussis toxin. 1 beta,25-Dihydroxyvitamin D3 had no effect on either hepatocyte cytosolic calcium or 32P-labeled lysophosphatidylinositol but prevented the 1 alpha,25-dihydroxyvitamin D3-induced increments. The results suggest that a G protein sensitive to pertussis toxin is required for the transduction of the lysophosphatidylinositol signal but not the generation of the signal. The ability of 1 beta,25-dihydroxyvitamin D3 to inhibit the 1 alpha,25-dihydroxyvitamin D3-induced changes in phospholipids suggests that the epimer may compete with 1 alpha,25-dihydroxyvitamin D3 for an initiating receptor.     

In vitro inhibition of lymphocyte proliferation by Pseudomonas aeruginosa phenazine pigments.

Human lymphocyte proliferation is inhibited in vitro in the presence of killed Pseudomonas aeruginosa or cell-free P. aeruginosa culture supernatants. A comparison of culture supernatants obtained under similar conditions from Staphylococcus aureus, Escherichia coli, P. aeruginosa, and Pseudomonas cepacia strains demonstrated that all P. aeruginosa supernatants were strongly inhibitory, whereas supernatants from other bacteria were mildly inhibitory or not inhibitory at all. These P. aeruginosa inhibitors prevent proliferative responses of resting cells upon mitogen activation and decrease [3H]thymidine uptake when added to human lymphocytes undergoing active proliferation in culture. The inhibitory effect is reversible and not due to cytotoxicity. Most of the inhibitory activity present in crude supernatants was detected in ultrafiltrates of molecular weights below 2,000. Purified P. aeruginosa pyocyanine, a low-molecular-weight phenazine pigment present in culture supernatant, was strongly inhibitory for lymphocyte proliferation. Extraction of pyocyanine and phenazine pigments from inhibitory P. aeruginosa supernatants eliminated their inhibitory activity. Inhibitors were recovered from reverse-phase chromatographic cartridges by both chloroform and methanol elution, indicating that pyocyanine and other phenazine pigments present in P. aeruginosa supernatants are responsible for the inhibition of lymphocyte proliferation. In addition to the identification of phenazine pigments as lymphocyte proliferation inhibitors, several criteria ruled out major contributions of P. aeruginosa polysaccharide, exotoxin A, and proteases to this phenomenon. P. aeruginosa strains selected for very low protease production or for very low exotoxin A production produced supernatants as inhibitory for lymphocyte proliferation as supernatants obtained from clinical P. aeruginosa isolates. Purified P. aeruginosa lipopolysaccharide and protease preparations failed to induce reversible lymphocyte proliferation inhibition. Finally, heat inactivation of P. aeruginosa supernatants at 100 degrees C for 60 min inactivates exotoxin A and proteases but produced only a moderate decrease of the inhibitory activity for lymphocyte proliferation.     

The effects of human ankle muscle vibration on posture and balance during adaptive locomotion

This study investigated the contribution of ankle muscle proprioception to the control of dynamic stability and lower limb kinematics during adaptive locomotion, by using mechanical vibration to alter the muscle spindle output of individuals' stance limbs. It was hypothesised that muscle length information from the ankle of the stance limb provides information describing location as well as acceleration of the centre of mass (COM) with respect to the support foot during the swing phase of locomotion. Our prediction, based on this hypothesis was that ankle muscle vibration would cause changes to the position and acceleration of the COM and/or compensatory postural responses. Vibrators were attached to both the stance limb ankle plantarflexors (at the Achilles tendon) and the opposing dorsiflexor muscle group (over tibialis anterior). Participants were required to walk along a 9-m travel path and step over any obstacles placed in their way. There were three task conditions: (1) an obstacle (15 cm in height) was positioned at the midpoint of the walkway prior to the start of the trial, (2) the same obstacle was triggered to appear unexpectedly one step in front of the participant at the walkway midpoint and (3) the subjects' walking path remained clear. The participants' starting position was manipulated so that the first step over the obstacle (when present) was always performed with their right leg. For each obstacle condition participants experienced the following vibration conditions: no vibration, vibration of the left leg calf muscles or vibration of the anterior compartment muscles of the lower left leg. Vibration began one step before the obstacle at left leg heel contact and continued for 1 s. Vibrating the ankle muscles of the stance limb during the step over an obstacle resulted in significant changes to COM behaviour [measured as displacement, acceleration and position with respect to the centre of pressure (COP)] in both the medial/lateral (M/L) and anterior/posterior planes. There were also significant task-specific changes in stepping behaviour associated with COM control (measured as peak M/L acceleration, M/L foot displacement and COP position under the stance foot during the step over the obstacle). The results provide strong evidence that the primary endings of ankle muscle spindles play a significant role in the control of posture and balance during the swing phase of locomotion by providing information describing the movement of the body's COM with respect to the support foot. Our results also provide supporting evidence for the proposal that there are context-dependent changes in muscle spindle sensitivity during human locomotion.