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Biomedical subjects

P Collier

Publications and source records attributed to P Collier.

31 records · Page 2Linked to original sources
PubMed1987

Reoperation for polytetrafluoroethylene bypass failure: the importance of distal outflow site and operative technique in determining outcome.

Of 724 bypasses with polytetrafluoroethylene grafts performed for critical ischemia during a 6-year period, 165 (23%) failed and necessitated reoperation for continued limb salvage. Forty-three failures occurred in 199 femoral-above-knee-popliteal bypasses (F-AKP), 33 failures in 177 femoral-below-knee-popliteal bypasses (F-BKP), 52 failures in 182 femorodistal bypasses (F-D), 28 failures in 85 axillofemoral bypasses (Ax-F), and nine failures in 81 femorofemoral bypasses (F-F). Our reoperative approach consisted of dissection of the distal anastomosis, longitudinal incision in the hood of the graft directly over the anastomosis, and proximal graft thrombectomy. Intimal hyperplasia was treated by patch angioplasty, proximal or distal progression of atherosclerosis was treated by a graft extension, and thrombectomy alone was performed when no cause of graft failure was identified. More recently, a totally new bypass was constructed in 27 cases of F-BKP or F-D failures. Reoperations featuring graft salvage for failed extra-anatomic and F-AKP bypasses yielded 3-year patency rates from the time of first reoperation of 71% and 52%, respectively, whereas for F-BKP and F-D reoperations, 3-year patency rates were 13% and 15%, respectively, at 3 years. However, totally new grafts to a different outflow artery in these settings had 3-year patency rates of 48% and 39%. These data support the aggressive use of reoperation with graft salvage when F-AKP or extra-anatomic graft failure reproduces critical ischemia. Conversely, a new bypass to a virginal outflow site, preferably with autologous vein, should be performed when a polytetrafluoroethylene F-BKP or F-D bypass fails.

Adult↗
PubMed1982

Health behaviors of women.

This article has reviewed both historical and current perspectives on women's health and illness behaviors. It has considered the existing risks to optimal health as well as the potential changes which may occur as women's roles and lifestyles continue to change. Jenkins' model was used to provide a framework for examining the sequence of events which frequently comprise a health behavior, and interventions were offered for the various categories of need--information, motivation, and specific skills to enhance action. Health care providers need to be facilitators of positive health in women but must encourage the female client to determine her own goals and behaviors. The nursing role can include assessing health and illness behaviors, assisting the client with development of manageable health goals, offering specific intervention strategies, and providing ongoing monitoring and support as the woman moves toward her desired goal. As nurses become more knowledgeable about preventive care for women of today, especially in regard to their unique needs and behaviors, perhaps positive health action may be encouraged not only for the prevention of disease but also for the joy of being healthy.

Attitude to Health↗
PubMed1981

Regional distribution of myelin basic protein in the central nervous system of quaking, jimpy, and normal mice during development and aging.

Myelin basic protein (MBP) was quantified using a RIA technique in the spinal cord, cerebellum, diencephalon plus brainstem region and cerebral hemispheres of two dysmyelinating murine mutants, quaking (qk) and jimpy (jp) mice. Comparison was made with normal control values. The whole life-span has been investigated: ie, ages ranging from 0 to 26 days for the jp, O to one year for the qk, and prenatal stage to three years for the control animals. Assays in the mutants at early ages were rendered feasible by the use of marker genes, which has allowed the diagnosis of the mutation at birth, 12 days before the expression of their typical tremor phenotype. Special care was given to the period of early myelinogenesis in order to clarify the dysynchrony between the various parts of the central nervous system. In normal mice, MBP was already detected in the brain of 19-day-old embryos. During development, rapid accumulation of MBP first occurred in the spinal cord then in the diencephalon, the brainstem, the cerebellum, and finally in the cerebral hemispheres. In the 25-day-old jimpy mutant, levels of MBP were found dramatically decreased, never exceeding 6% of the normal controls in any of the areas investigated. The situation for the quaking mouse was quite different. This mutant could be investigated up to one year old. At that age, a high discrepancy was observed between the values found in the brain and in the spinal cord (respectively, 10% and 35%) compared to normal controls. In both mutants, not only were the levels of MBP decreased, but also its appearance during development was delayed. Nevertheless, in both mutants the caudo-rostral timing of myelination as assayed by MBP levels was maintained. Furthermore, the later myelination occurred, the stronger weas the deficit in MBP. Interestingly, in the quaking mutant, the specific plasticity of the spinal cord was exemplified by its ability to reduce constantly, even at an advanced age, its initial deficit of MBP.

Aging↗
PubMed1980

Accumulation of GFA, the monomeric precursor of the gliofilaments, during development in normal mice and dysmyelinating mutants.

Astrocytic reactivity during the myelination period in the mouse was studied with immunochemical method, ie, quantitative determination of the soluble pool of the GFA protein. There is normally a maximum content at the time of early myelinogenesis in any structure; then the GFA level decreases and finally keeps constant for a long period during the adult life. This evolutive pattern is also observed in the dysmyelinating mutant quaking, with a permanent shift toward higher values especially in areas of earlier maturation. In the jimpy mutant, practically devoid of myelin, the increase of GFA occurs but does not stop until death, at 25 days postnatal. This study points out 1) the capacity of astrocytes to synthesize surprisingly high amounts of soluble GFA at periods of intense metabolic activity, and 2) the reactivity of astrocytes in relation to the degree of deficiency of the myelinating oligodendrocytes.

Animals↗
PubMed1980

The application of statistical moment theory to the evaluation of in vivo dissolution time and absorption time.

Moments analysis has been applied to the calculation of mean (in vivo) dissolution time (MDT) and mean absorption time (MAT) from plasma level of drug versus time data. Methods for accurately estimating the MDT under varying conditions, limitations of the methods, and interpretation of the data are presented. The importance of accurate estimates of the terminal rate constant (lambda 2) and the drug concentration at the time of withdrawing the final plasma sample (Cz) is emphasized in connection with extrapolation to t = affinity. The appropriate use of a logarithmic trapezoidal equation for calculating the area under the moments curve (AUMC) is shown to increase the accuracy of estimating MDT.

Absorption↗
PubMed1979

GFA and S 100 protein levels as an index for malignancy in human gliomas and neurinomas.

Human glia-specific proteins S 100 and GFA were quantitated by use of a rocket immunoelectrophoresis technique with monospecific antisera. No relation was found between the S 100 protein content of an astrocytoma and its degree of neoplasia. However, the lower the GFA protein content of the astrocytoma, the more malignant it was. Similarly, the more malignant a neurinoma was, the lower was its S 100 protein content. Therefore, the levels of these proteins might be used as indexes of neoplastic dedifferentiation.

Astrocytoma↗
PubMedDate not supplied

Growth kinetics of Escherichia coli and expression of a recombinant protein and its isoforms under heat shock conditions.

Preinduction culture conditions were found to have significant impact on the expression and post-translational modification of a recombinant human protein in Escherichia coli under heat shock conditions (30 to 42 degrees C shift). Higher preinduction growth rates (micrograms) favored better cell viability, greater cell mass yields, and increased cloned gene expression during induction. Formation of recombinant protein isoforms (those containing N epsilon-modified lysine residues) exhibited an increasing trend with increasing micrograms. The different extents of post-translational modifications were suspected to be linked to the different concentrations of certain heat shock protein chaperones resulting from different micrograms. In view of the extensive involvement of E. coli heat shock proteins in cellular activities-including the synthesis, processing, modification, and degradation of proteins-at elevated temperatures, it is believed that micrograms dictated the cellular resources available for synthesizing the heat shock proteins required for cell survival, which in turn determined the ability of the cells to respond to the heat shock. With a higher micrograms both the synthesis of host proteins (as indicated by cell growth and survival) and the cloned gene expression were enhanced. The results demonstrate that there exists an intermediate micrograms for optimum production of the unmodified foreign protein in a heat shock environment. More importantly, they also illustrate the feasibility of improving the recombinant protein homogeneity in fermentation, thereby facilitating downstream processing.

Bioreactors↗
PubMedDate not supplied

Failure of topical vegetable oils to prevent essential fatty acid deficiency in a critically ill patient receiving long-term parenteral nutrition.

This case report describes the failure of topical vegetable oils containing esters of linoleic acid to prevent essential fatty acid deficiency in a critically ill patient with trauma. A 40-year-old black man injured in a motor vehicle accident developed essential fatty acid deficiency after being maintained on long-term, fat-free parenteral nutrition plus topical vegetable oil application because of the presence of severe hypertriglyceridemia. Biochemical evidence of this deficiency included a decrease in serum linoleic, a-linolenic, and arachidonic acid levels with a corresponding increase in oleic and palmitoleic acid levels. Cutaneous manifestations consistent with this syndrome were also present. After 3 weeks of daily topical treatments with vegetable oils rich in linoleic acid, biochemical abnormalities of deficiency were still evident. Over the following 2 1/2 months, 4% to 22% of the total caloric intake was delivered as intravenous fat in addition to continued topical administration of vegetable oil. Only after supplementation with intravenous fat did the patient demonstrate clinical and biochemical signs of improvement. The results show that cutaneous administration of vegetable oils as the sole source of linoleic acid may be unable to prevent or treat essential fatty acid deficiency in a critically ill surgical patient.

Administration, Cutaneous↗