Biomedical subjects
Publications and source records attributed to P Donovan.
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99mTc-labeled myocardial perfusion agents are excreted through the hepatobiliary system and can be used in the evaluation of the duodenogastric reflux that occurs during routine cardiac imaging. The resultant gastric activity can overlap the inferior wall of the left ventricle (LV) and can thus mimic reverse redistribution of the LV inferior wall on dual-isotope SPECT. We report a case of significant gastric activity, which leads to abnormally low LV ejection fraction and akinesis of the LV wall in addition to the appearance of reverse redistribution. This case report illustrates that care should be taken in the performance and interpretation of (99m)Tc-tetrofosmin SPECT in the presence of duodenal reflux. This condition could be mistaken for reverse redistribution in the inferior wall of the LV with concomitant underestimation of the LV and regional wall motion.
Stem cell factor (SCF) is expressed as an integral membrane growth factor that may be differentially processed to produce predominantly soluble (S) (SCF(248)) or membrane-associated (MA) (SCF(220)) protein. A critical role for membrane presentation of SCF in the hematopoietic microenvironment (HM) has been suggested from the phenotype of the Steel-dickie (Sl(d)) mice, which lack MA SCF, and by studies performed in our laboratory (and by others) using long-term bone marrow cultures and transgenic mice expressing different SCF isoforms. Steel(17H) (Sl(17H)) is an SCF mutant that demonstrates melanocyte defects and sterility in males but not in females. The Sl(17H) allele contains a intronic mutation resulting in the substitution of 36 amino acids (aa's) in the SCF cytoplasmic domain with 28 novel aa's. This mutation, which affects virtually the entire cytoplasmic domain of SCF, could be expected to alter membrane SCF presentation. To investigate this possibility, we examined the biochemical and biologic properties of the Sl(17H)-encoded protein and its impact in vivo and in vitro on hematopoiesis and on c-Kit signaling. We demonstrate that compound heterozygous Sl/Sl(17H) mice manifest multiple hematopoietic abnormalities in vivo, including red blood cell deficiency, bone marrow hypoplasia, and defective thymopoiesis. In vitro, both S and MA Sl(17H) isoforms of SCF exhibit reduced cell surface expression on stromal cells and diminished biological activity in comparison to wild-type (wt) SCF isoforms. These alterations in presentation and biological activity are associated with a significant reduction in the proliferation of an SCF-responsive erythroid progenitor cell line and in the activation of phosphatidylinositol 3-Kinase/Akt and mitogen-activated protein-Kinase signaling pathways. In vivo, transgene expression of the membrane-restricted (MR) (SCF(X9/D3)) SCF in Sl/Sl(17H) mutants results in a significant improvement in peripheral red blood cell counts in comparison to Sl/Sl(17H) mice.
Two of the major cognitive theories of depression, the theory of Beck [Beck, A. T. (1967). Depression: clinical, experimental and theoretical aspects. New York: Harper & Row. and Beck, A. T. (1987) Cognitive models of depression. Journal of Cognitive Psychotherapy: an International Quarterly, 1, 5-37] and the hopelessness theory [Abramson, Metalsky, & Alloy, (1989) Hopelessness depression: a theory-based subtype of depression. Psychological Review, 96, 358-372], include the hypothesis that particular negative cognitive styles increase individuals' likelihood of developing episodes of depression, in particular, a cognitively mediated subtype of depression, when they encounter negative life events. The Temple-Wisconsin Cognitive Vulnerability to Depression (CVD) project is a two-site, prospective longitudinal study designed to test this cognitive vulnerability hypothesis, as well as the other etiological hypotheses of Beck's and the hopelessness theories of depression. In this article, based on CVD project findings to date, we review evidence that the hypothesized depressogenic cognitive styles do indeed confer vulnerability for clinically significant depressive disorders and suicidality. In addition, we present evidence regarding moderators of these depressogenic cognitive styles, the information processing and personality correlates of these styles and the possible developmental antecedents of these styles. We end with a consideration of future research directions and the clinical implications of cognitive vulnerability to depression.
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The objective of this study was to determine whether a split-thickness skin graft can be implanted deep to the skin and whether it can be expanded. We also wanted to find out whether this implanted and expanded split-thickness skin graft can be used as a new source of skin grafts and as a pedicle flap. A tissue expander mounted on a Dacron sheet backing was specially designed for this experiment. Six female Hanford minipigs weighing 20 to 25 kg were operated on in three stages. In stage one, a split-thickness skin graft 0.03 in thick was harvested from the back, placed dermal side out over the expander, and sutured to the Dacron backing. The expander with the overlying split-thickness skin graft was then implanted deep to the panniculus carnosus muscle. Daily expansion was started 2 weeks after implantation to obtain a total volume of 1300 to 2500 cc. In the second stage, performed 4 to 6 weeks after implantation, the skin over the expander was elevated superficial to the panniculus carnosus muscle as a ventrally based flap, and the panniculus carnosus muscle was next elevated as a dorsally based flap lined on its deep surface with the implanted/expanded skin. Full-thickness skin grafts obtained from this implanted/expanded skin and from normal skin were transplanted to two 3 x 3 cm skin defects. The panniculus carnosus muscle implanted/expanded skin flap was then turned 180 degrees and sutured to a dorsally created skin defect. In the third stage, 4 weeks later, we noted the quality, texture, and appearance and obtained punch biopsies from normal skin, normal skin graft, implanted/expanded skin graft, and panniculus carnosus muscle implanted/expanded flap for histopathologic examination. All skin grafts "took" well, survived implantation, and were expanded successfully. The initial surface area of implanted split-thickness skin graft showed a net increase of 8 to 193 percent (mean percentage net increase 90 percent). This implanted/expanded skin also was retransplanted successfully to a skin defect. In all six minipigs, a skin-lined panniculus carnosus muscle implanted/expanded skin flap was constructed and survived transfer to an adjacent skin defect. The smallest flap of panniculus carnosus muscle implanted/expanded skin measured 10 x 12 cm and the largest 12 x 28 cm (mean surface area 228 cm2).
The course planning team at Southampton University College of Midwifery wanted to offer a diploma course which reflected the realities of midwifery education in the clinical setting. For this a curriculum model--The Wave--was developed. The Wave is not a static model, but reflects the changes a midwifery curriculum must absorb in context and circumstances. Allocation of students to clinical areas is linked with course content, allowing direct application of theory to practice and practice to theory.
OBJECTIVE: To improve the quality and accessibility of psychiatric service in the primary care setting. DESIGN: Under the liaison-attachment model, a senior psychiatry trainee provided psychiatric consultations part-time in general practice over an 18-month period. Patients regarded by the participating doctors as having significant psychiatric problems were referred to the trainee for consultation. SETTING: Four group general practices, involving 18 doctors, took part in the scheme. PARTICIPANTS: During the study 172 patients with a wide spectrum of diagnoses were assessed. Near the end of the 18-month period the participating general practitioners provided their evaluations of the scheme. INTERVENTION: In almost all cases standard treatment was provided in the primary care setting and administered by either a general practitioner, the trainee or both working collaboratively together. OUTCOME MEASURES: The general practitioners evaluated the results of the consultations and the effect of the service on their referral patterns. They also rated the overall impact of the scheme on their own knowledge and skills, the quality of care, and its accessibility. RESULTS: The quality of outcome, if known, was regarded as satisfactory in 88% of cases. The reported frequency of referrals to psychiatrists in private practice dropped significantly. The participating doctors perceived improvements in their own abilities to deal with psychiatric problems and regarded the quality and accessibility of psychiatric care to be enhanced by the scheme. CONCLUSIONS: The psychiatric liaison-attachment model, developed in Britain, is applicable and effective in the Australian primary care setting.
We have characterized the mouse Mos proto-oncogene product, pp39Mos, in murine fibroblasts. When expressed in NIH3T3 cells under the influence of the long terminal repeat regulatory element from Moloney murine sarcoma virus [NIH(pTS-1) cells], the Mos protein was present in low levels and had a half-life of about 30 min. In extracts from NIH(pTS-1) cells, we detected additional forms of Mos protein that apparently arose from internal initiation codons (p24Mos and p29Mos) or from upstream non-AUG initiation codons (p42Mos and p44Mos). The Mos protein was found to exist in these cells as a phosphoprotein, pp39Mos, and, when immunoprecipitated with an antiserum specific for the Mos N-terminus [anti-Mos(6-24)], had autophosphorylating kinase activity. We found that anti-Mos(6-24) also detected non-Mos protein kinase activity and non-Mos phosphoproteins in addition to p39Mos. We present evidence, on both the RNA and protein levels, that non-transformed mouse 3T3 cells do not express endogenous Mos.
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