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Biomedical subjects

T Cross

Publications and source records attributed to T Cross.

At least 19 recordsLinked to original sources
PubMed2001

MFO induction in fish by filtrates from chlorine dioxide bleaching of wood pulp.

Spent bleaching liquors from pulp bleached with chlorine dioxide were assessed for their potency to induce hepatic mixed function oxygenase enzymes (MFO) in rainbow trout, as indicated by activity of ethoxyresorufin-o-deethyase (EROD). Filtrates were collected from two kraft mills in Central Canada to assess the potency of filtrates from hardwood and softwood bleaching. All mill-scale bleaching filtrates induced MFO activity, and filtrates from softwood pulp bleaching appeared more potent than filtrates from hardwood bleaching. Filtrates from the final bleaching stage were most potent, and filtrates from the first stage were the least potent. In laboratory bench-scale bleaching experiments, pulp from softwood and hardwood kraft mills in Eastern Canada was bleached via an industry-standard 5-stage chlorine dioxide bleaching sequence. The filtrates were collected and used in fish bioassays to assess EROD-inducing potency. Potency of bench-scale filtrates varied depending on wood furnish (i.e. softwood vs. hardwood) and the bleaching stage, with all bench-scale filtrates being much weaker EROD inducers than mill-scale filtrates. Recycled paper mill washwater is a possible source of compounds causing increased potency of the mill-scale filtrates.

Animals↗
PubMed2000

PKC-delta is an apoptotic lamin kinase.

Protein kinase C-delta is activated during apoptosis, following proteolytic cleavage by caspase 3. Furthermore, overexpression of the catalytic kinase fragment of PKC-delta induces the nuclear phenotype associated with apoptosis, though the molecular basis of this effect has not been determined. In these studies we have examined the role of PKC-delta in the disassembly of the nuclear lamina at apoptosis. The nuclear lamina is disassembled during mitosis and apoptosis and mitotic disassembly involves hyperphosphorylation of lamin proteins by mitotic lamin kinases. During apoptosis, lamin proteins are degraded by caspase 6 and the contribution made by phosphorylation has not been proven. We show here that protein kinase C-delta co-localized with lamin B during apoptosis and activation of PKC-delta by caspase 3 was concomitant with lamin B phosphorylation and proteolysis. Inhibition of PKC-delta delayed lamin proteolysis, even in the presence of active caspase 6, whilst inhibitors of mitotic lamin kinases were without effect. In addition recombinant human PKC-delta was able to phosphorylate lamin B in vitro suggesting that its actions are direct and not via an intermediary kinase. We propose that PKC-delta is an apoptotic lamin kinase and that efficient lamina disassembly at apoptosis requires both lamin hyperphosphorylation and caspase mediated proteolysis.

Acetophenones↗
PubMed2000

Impact of facial paralysis on patients with acoustic neuroma.

OBJECTIVE: To assess the psychological distress, the ways of coping with that stress, and the self-esteem of patients with facial paralysis after acoustic neuroma surgery. Possible predictors and associations between these measures were also explored. STUDY DESIGN: Four validated questionnaires were completed by patients with facial paralysis after acoustic neuroma surgery: 1) the Derriford Appearance Scale (DAS) to measure psychological distress, 2) the COPE questionnaire to measure how patients cope with facial paralysis, 3) the Personal Report questionnaire to measure the self-esteem of patients, and 4) the Facial Paralysis Questionnaire (FPQ) to measure the severity of facial paralysis. PATIENTS: One hundred three patients with facial paralysis after surgical removal of acoustic tumors. RESULTS: Distress spanned a wide range in these patients. There was no statistically significant association between the level of distress and the grade of facial paralysis or between time since operation and levels of distress. Women had higher levels of distress (P = .02) and a significant negative correlation was found between levels of distress and age (r = -0.28, P = .005). High levels of distress were associated with low levels of self-esteem, as shown by the significant negative correlation between level of distress and self-esteem (r = -0.59, P = .01). A significant correlation between distress and maladaptive coping (r = 0.31, P = .002) was also found. Stepwise multiple regression of the distress scores revealed that self-esteem was the most important contributing factor (standardized coefficient beta -0.60, P = .0001), followed by age (beta -0.24, P = .006) and sex (beta -0.21, P = .04). This model explained 44% of the distress variance. CONCLUSION: Clinicians must be aware of the distress felt by some patients experiencing facial palsy after acoustic neuroma surgery and that the level of distress may not be related to the clinical grade of the facial nerve paralysis. People with low self-esteem, young people, and women suffer from more distress due to the facial palsy. Clinicians should thoroughly counsel patients before and after surgery and should implement measures that increase patients' self-esteem and decrease their distress, especially in these high-risk groups.

Adaptation, Psychological↗
PubMed1999

Fairness and health care decision making: testing the group value model of procedural justice.

Considerable research has supported the notion that procedural justice is important to individuals independent of outcome considerations. Tyler and his associates (Lind and Tyler, 1988; Lind and Earley 1992; Tyler, 1989) proposed that this is so because procedural justice serves a group value function. In the present research, we explore aspects of this group value formulation in a real life health care context. Specifically, we assessed the relationship between individuals' appraisals of procedural justice following health care treatment decisions as well ass (i) expectations for different consequences to self; (ii) estimates of how they were viewed by the health care authorities; (iii) attributions about the reasons for their treatment; and (iv) ratings of emotional reactions. Results confirmed many components of the relational, group value model of procedural justice (Lind and Tyler, 1988; Lind and Earley, 1992; Tyler, 1989). Specifically, respondents who felt that they had been treated fairly expected that their status and their relationship with the health care decision maker and others in their health care group would improve; perceived that the health care decision maker would rate them positively on a variety of personality dimensions; felt that the health care decision maker's interactions with them revealed quite a lot about the decision-maker's personality characteristics; and indicated increased levels of pride and pleasure as well as lower levels of anger as a result of their treatment. Results were discussed from several frameworks including Markus and Kitayama's (1991) concept of independent and the interdependent self.

Decision Making↗
PubMed1997

High-resolution polypeptide structure in a lamellar phase lipid environment from solid state NMR derived orientational constraints.

BACKGROUND: Solid-state nuclear magnetic resonance (NMR) spectroscopy provides novel structural constraints from uniformly aligned samples. These orientational constraints orient specific atomic sites with respect to the magnetic field direction and the unique molecular axis of alignment. Solid-state NMR is uniquely and ideally suited for providing such structural constraints on polypeptides and proteins in a lamellar phase lipid environment. Membrane protein structure represents a great challenge for structural biologists; a new approach for characterizing high resolution three-dimensional structure in such an environment is needed. RESULTS: The optimal use of orientational constraints for defining three-dimensional structures is demonstrated with the elucidation of the gramicidin A channel structure at high resolution. Initial structures are refined against both the experimental constraints and the CHARMM energy using a novel simulated-annealing protocol to define torsion angle solutions with an error bar of approximately +/- 5 degrees. CONCLUSIONS: This analysis results in the determination of a high-resolution, time averaged structure of gramicidin A obtained in a lipid bilayer environment above the gel-to-liquid crystalline phase transition temperature. It is demonstrated that solid-state NMR can be used to establish polypeptide, and potentially protein, structures in such an environment. Furthermore, this high-resolution structure is demonstrated to provide new insights into polypeptide function. For the gramicidin A channel the roles of the indole groups that facilitate ion transport and details of the cation solvation environment provided by the amide oxygens are characterized.

Amino Acid Sequence↗
PubMed1997

Impact of level III verification on trauma admissions and transfer: comparisons of two rural hospitals.

PURPOSE: To study the impact of Level III verification and other changes in rural hospitals on trauma delivery and to examine factors affecting transfer to a Level I trauma center. SETTING: Two rural Kentucky hospitals and a Level I trauma center. METHOD OF REVIEW: Concurrent review of all trauma patients in 1988 and re-review of the same parameters in 1995. FINDINGS: In 1988, both hospitals had similar management practices in trauma care. A significant number of patients were transferred for (a) patient choice, (b) serious and/or multiple trauma, (c) specialty care in non-life threatening situations, and (d) to exclude a potentially serious problem seen on radiologic evaluation (usually questionable cervical spine or widened mediastinum). Both hospitals had major changes in trauma delivery. One hospital received Level III verification, and the other had changes that lessened the general surgeon's involvement with initial evaluation and treatment. A re-review in 1995 disclosed major changes at both institutions. Transfers to exclude radiologic abnormalities had virtually disappeared. The Level III status had increased the surgical involvement in that hospital; there was actually an increase in patients transferred to the Level I hospital and an increase in patient acuity. More operations were performed locally, and the care was more efficiently delivered. The other hospital had a large increase in transfers and decreased admissions locally as general surgical involvement decreased. CONCLUSIONS: The factors related to patient transfer for trauma care are complex and require careful elucidation to improve care. The development of a Level III trauma service appeared to increase the number of seriously injured patients treated in the rural hospital and the efficiency of the care delivered.

Concurrent Review↗
PubMed1996

PCR amplification of a polymorphic minisatellite VNTR locus in whiting (Merlangius merlangus L.).

An approach has been developed for the screening of allelic variation of minisatellite DNA loci that substantially reduces the time and hazards involved. Primers were designed for a minisatellite region isolated from a gadoid fish species (Merlangius merlangus L.), enabling amplification by polymerase chain reaction, so that differences in the number of minisatellite repeat units (allelic variability) were detectable by ethidium bromide fluorescence (over UV light) following separation by agarose gel electrophoresis. This amplifiable minisatellite variable number tandem repeat region, the first non-primate marker of its kind can be used successfully with DNA extracted by a rapid Chelex protocol. From a sample of 97 individuals, 24 alleles were resolved (750-2200 kb) and heterozygosity was estimated at 0.94.

Alleles↗
PubMed1979

Taxonomic and serologic studies on Micropolyspora faeni and Micropolyspora strains from soil bearing the specific epithet rectivirgula.

The results of serological studies on six strains of Micropolyspora faeni from hay, sputum and plant debris, and five strains of Mip. rectivirgula from soil indicated no significant differences between the two species. Antisera raised in rabbits against purified antigens of the type strains were used to compare the 11 strains by immunoelectrophoresis. The detailed antigenic composition of the type strains was also determined by two-dimensional immunoelectrophoresis against specific rabbit antisera and pooled serum samples from patients suffering from farmer's lung. Cross-reacting antigens were identified by intermediate gel immunoelectrophoresis. The close similarity of the two species was confirmed by the results of 60 morphological physiological and biochemical tests applied to the 11 strains. We consider that the strains belong to a single species and propose that the specific epithet faeni be conserved for the taxon.

Antigens, Bacterial↗