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Biomedical subjects

S Murphy

Publications and source records attributed to S Murphy.

At least 577 records · Page 32Linked to original sources
PubMedDate not supplied

Extension of platelet concentrate storage.

Extension of the storage time of platelet concentrates in a satellite bag which is part of a new blood bag system was studied by reinfusing autologous 51Cr-labeled platelets into normal volunteers, and measuring postinfusion platelet counts and bleeding times in patients requiring platelet transfusions. This satellite bag, made of polyvinylchloride plasticized with a new agent, was found to protect platelet concentrates against fall of pH better than other containers studied. This protection was felt to be due to the greater gas permeability of the new plastic. Mean in vivo recovery and half-life (greater than 31% and 3.3 days, respectively) of autologous reinfused platelets were satisfactory following 5 days of storage. Following 7 days of storage, mean recovery was 41 percent and half-life was 2.8 days. Peripheral platelet count increments in patients following platelet transfusions with concentrates stored 4 to 7 days in the new plastic were comparable to increments following transfusion of platelets stored 2 to 3 days in the other plastics studied. Bleeding times shortened in three of four patients receiving platelet concentrates stored from 4 to 6 days in the new plastic. Platelet concentrates stored in the new bag at 20 to 24 degrees C with flat-bed or elliptical agitation could be transfused for up to 5 days following phlebotomy with acceptable clinical results. The new plastic container is promising for storage of platelet concentrates for up to 7 days. Due to the higher pH of 50-ml platelet concentrates stored in bags made with the new plastic, the concentrates were superior at any storage interval to those stored in bags made of the other plastics studied.

Blood Coagulation Tests↗
PubMedDate not supplied

In vitro function and in vivo viability of stored platelet concentrates. Effect of a secondary plasticizer component of PVC storage bags.

Previous studies have shown that CL-2399 (Cutter) and PL-130 (Fenwal) polyvinyl chloride (PVC) plastic bags are unsatisfactory for storage of platelet concentrates (PC) at 22 degrees C. In an effort to explain the effects of plastic bags, the chemical make-up of CL-2399 and PL-130 PVC films was determined and compared with that of P1-146 (Fenwal) PVC, which is satisfactory for PC storage at 22 degrees C. The only significant difference between the three materials was the incorporation of tetrahydrofurfuryl oleate (THFO) as a secondary plasticizer in CL-2399 and PL-130. The response of platelets to aggregating agents, uptake of serotonin, recovery from hyptonic stress, and serotonin release during storage following storage in a modified CL-2399 plastic prepared without THFO and designated CL-3000 (Cutter) was equivalent to PL-146 and far superior to CL-2399. In vivo studies in two laboratories of platelets stored in CL-3000 bags showed satisfactory recovery (56 +/- 4.2% and 46.7 +/- 2.7%) and survival (6.4 +/- 0.4 days and 7.4 +/- 0.6 days). From these studies we conclude that the THFO secondary plasticizer component of PL-130 and CL-2399 is the cause of the poor platelet viability of platelets stored in these plastic bags. The mechanism of impairment is not known. The causative agent(s) may be degradation products of THFO (formed during manufacture of the PVC film) that are leached from the plastic into PC during storage.

Blood Platelets↗
PubMedDate not supplied

Stability of plasma fibrinogen during storage of platelet concentrates at 22 degrees C.

Platelet concentrates (PC) are stored for up to 5 days at 22 degrees C prior to infusion. Since considerable suspending plasma is infused with the platelets, we examined the integrity of plasma fibrinogen from stored PC. The concentration of fibrinogen after storage was normal. After purification, fibrinogen from stored PC had normal thrombin time and rate of polymerization of fibrin monomer, and after reduction, its A alpha, B beta, and gamma chains had normal mobility on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Assays of plasma from stored PC for fibrinogen-fibrin degradation products were negative. When 125I-fibrinogen was added to PC prior to storage and supernatant plasma was filtered in a sepharose 4B column after storage, radioactivity eluted in a single, symmetrical peak with no evidence for formation of low or high molecular weight material. These results make it unlikely that thrombin, plasmin, or other proteolytic activity is generated during storage. The levels of factors V and VIII fell to 40 to 65 percent of control values while the activities of factors IX, X, and XI did not change significantly during storage. We conclude that suspending plasma fibrinogen and other coagulation factors are remarkably stable during PC storage. They should be of value during the support of patients with massive hemorrhage.

Blood Coagulation Tests↗
PubMedDate not supplied

Paired comparison of the in vivo and in vitro results of storage of platelet concentrates in two containers.

Both in vitro and in vivo methods are used to test the validity of techniques for storing platelet concentrates for transfusion. In this study, the characteristics of platelet concentrates stored for 5 days at 22 degrees C in two different containers were evaluated by paired comparison using two in vitro measurements and two in vivo measurements. On two occasions, 10 normal subjects donated concentrates that were stored in containers of either the CLX system or the PL-146 system. The first plastic used was chosen at random. If necessary, a concentrate platelet count was reduced to 1,200,000 per microliters by addition of plasma to avoid pH fall. Mean recoveries were 48.2 +/- 10.6 percent (mean +/- 1 SD) and 42.4 +/- 7.8 percent for platelets stored in containers of the CLX and PL-146 systems, respectively. Similarly, survivals (T 1/2 in days) were 3.4 +/- 0.8 and 3.0 +/- 0.7, respectively. Since a paired design was used, the superiority of the CLX system was demonstrable with a one-tailed paired t test. If a paired design had not been used, a pooled t test would have been appropriate and the differences would not have been significant. This result emphasizes the value of the paired design. Furthermore, two in vitro measurements that reflect platelet morphology, dispersion of the size distribution and extent of shape change with adenosine diphosphate, were superior for platelets stored in CLX containers as well, suggesting a relationship between these measurements and in vivo viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMedDate not supplied

Extended storage of platelets in a new plastic container. II. In vivo response to infusion of platelets stored for 5 days.

A new blood container material (PL 1240 plastic) made of polyvinyl chloride containing a tri(2-ethylhexyl) trimellitate plasticizer was evaluated in three laboratories. When platelet concentrates (50-60 ml) were stored on a variety of agitators for 7 days at 22 +/- 2 degrees C, poststorage pH (mean +/- SD) ranged from 7.29 +/- 0.05 (6 rpm elliptical rotator) to 6.87 +/- 0.8 (70 cycles per minute flatbed agitator). The platelet counts ranged from 1.51 +/- 0.12 to 0.95 +/- 0.36 X 10(6) per microliter. Morphology scores and hypotonic shock response values of platelets stored 7 days in PL 1240 plastic containers were better than those noted following 3-day storage of control platelets in PL 146 plastic containers. The percent discharge of lactic dehydrogenase from platelets stored 7 days in PL 1240 plastic containers for 3 days (p less than 0.05). Mean platelet recoveries of 44 +/- 15 percent (n = 11; 111Indium) and 39 +/- 8 percent (n = 29; 51Chromium) were seen when autologous platelets were infused following 5-day storage in PL 1240 plastic bags. Platelet half-lives of 3.6 +/- 0.4 (n = 9) 4.1 +/- 0.4 (n = 20) days were reported in the two laboratories which used 51Cr labeling, while survival values of 7.0 +/- 1.0, 2.8 +/- 0.8, and 5.4 +/- 1.9 days were seen when data from the 111Indium studies (n = 11) were analyzed using linear, exponential, and multiple hit programs, respectively. Platelets stored for 5 days also were administered to 13 thrombocytopenic oncology patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMedDate not supplied

Extension of platelet concentrate storage to 7 days in second-generation bags.

Platelet concentrates stored for 7 days in 50 ml of plasma in both thin film and enlarged variations of the standard 5-day CLX plastic bags were evaluated for pH maintenance and in vivo viability by two laboratories working independently. 51Cr-labeled platelets were reinfused into normal volunteers at the end of storage and recovery and half-life calculated. The pH was maintained well; less than 10 percent of units fell below 6.0 at 7 days. Mean 7-day recovery for both laboratories was 43.6 +/- 11.6 percent in the thin-film bag and 45.4 +/- 8.52 percent in the enlarged bag, compared with 43.6 +/- 8.8 percent at 5 days in the 5-day plastic licensed bag. After 7 days storage the half-life was 3.6 +/- 0.9 days in the thin-film bag and 3.7 +/- 0.6 days in the enlarged bag, compared with 3.6 +/- 0.5 days in the previously licensed CLX plastic bag after 5 days. Thus, platelet viability was maintained well at 7 days of storage in both of the container variations that allowed increased gas exchange.

Blood Platelets↗
PubMedDate not supplied

Plasma free fatty acid metabolism during storage of platelet concentrates for transfusion.

New containers allow storage of platelet concentrates (PC) at 22 degrees C for up to 7 days, during which glycolytic and oxidative metabolism is vigorous. Recent evidence suggests that 85 percent of adenosine triphosphate regeneration is based on oxidative metabolism and that substrates other than glucose may be used. Because platelets can oxidize free fatty acids (FFA) as a possible source of energy during storage, the authors studied their availability, distribution, and turnover. Plasma FFA concentration was unchanged after 1 day of PC storage but significantly increased on Days 3, 5, and 7. Platelet-free plasma (PFP) stored under the same conditions as PC demonstrated a progressive increase in FFA, suggesting that some of the FFA accumulating in PC were derived from plasma rather than platelets. Indeed, during PC storage, plasma triglycerides decreased significantly, suggesting that they are a possible source of the increased levels of FFA found on Day 3 and thereafter. Thus, PC have a plasma FFA pool available continuously for oxidation during storage. Studies with radiolabeled palmitate suggested that FFA oxidation by platelets occurs during storage. The current findings show that plasma FFA could be a significant substrate for oxidative metabolism during storage of PC and that the oxidized FFA are replenished at least in part from plasma. These results may allow platelet storage to be improved, particularly in synthetic media.

Blood Preservation↗
PubMedDate not supplied

"Living with the dirty secret": problems of disclosure for methadone maintenance clients.

This article focuses on the management of stigma by methadone maintenance patients. It explores (1) the consequences of this persistent stigma, which necessitates the need for secrecy, (2) the adaptations made in order to successfully "pass as normal," and (3) the contexts in which methadone-maintained individuals decide to disclose their stigmatized status. The data reported and analyzed were gathered between 1980 and 1989 during a series of studies funded by the National Institute on Drug Abuse. The three studies--"Women on Methadone," "Getting Off Methadone," and "Alameda County Methadone Study"--utilized qualitative, in-depth interviews and ethnographic sampling techniques, primarily chain referral sampling. After ten years of interviewing women and men in various stages of their methadone maintenance careers, recurring themes emerged, one of which was that being a methadone patient is a marginal identity; not quite junkie, not quite conventional. Clients' efforts to manage this stigmatized identity were often shrouded in anguish and secrecy. Methadone patients were in a kind of identity limbo; a holding pattern between two extremely different social worlds. They were trying to effect an identity transformation; however, in many circumstances they were still associated with and defined by their "dirty secret."

Adult↗
PubMedDate not supplied

Women who use cocaine too much: smoking crack vs. snorting cocaine.

Monique (an African-American 19-year-old) and Becky (a white 21-year-old) were interviewed as part of a NIDA-funded study of women and cocaine. Although they were not necessarily typical, they do illustrate some of the differences among women who use cocaine. Despite the fact that they were close in age and both used cocaine, their scenarios and outcomes were very different, as one was a white middle-class woman and the other was an underclass woman of Color. The argument presented in this article is that it is not simply substance use that frames the experiences of women who use cocaine too much, but the social class mediated by gender and race. Through these life histories, the lives of these women are examined prior to cocaine use. Then the differential processes of initiation into and continuation of cocaine are described and analyzed, followed by a discussion of their lives after cocaine use.

Adult↗
PubMedDate not supplied

Walking the tightrope: balancing health and drug use.

This article stems from a study on San Francisco drug users and their health care experiences. Two hundred thirty-eight study participants were administered depth interviews and questionnaires to reveal a variety of health concerns and health behaviors. For these analyses, which focused on health practices and risky behaviors, the sample was divided into two groups: marijuana users, and other drug users (including methamphetamine, cocaine, heroin, and crack). The findings indicate that drug users behave similarly to the general population regarding health practices, such as eating regularly, sleeping regularly, taking vitamins, and exercising. One finding of interest was the high-risk sexual behaviors of the young, educated marijuana users. A majority of participants demonstrated strong concerns for their health and well-being, and further encouragement on this front is advised. Future research and directions for interventions are recommended.

Adult↗
PubMedDate not supplied

Temporal neocorticectomy in management of intractable epilepsy: long-term outcome and predictive factors.

We report the results of a long-term follow-up study of 50 patients who underwent removal of temporal neocortex with preservation of deeper limbic structures as surgical therapy for intractable temporal lobe epilepsy. The follow-up period ranged from 3 to 15 years. Preoperative EEG investigations were based on interictal discharges alone. Three factors were predictive of a good outcome: (a) A clear unilateral anterior-midtemporal focus (p less than 0.01), (b) stereotypical onset of temporal lobe seizure (p less than 0.005), and (c) greater volume of tissue removed at operation (p less than 0.05). Overall results showed that 62% of patients experienced an outcome of "cure" or "almost cure," as classified according to a modified version of Crandall's criteria (Crandall's I and II). Those who experienced a significant reduction in seizures but who continued to have intractable epilepsy (Crandall's III) were not considered to have had a good result. Overall outcome compares favorably with other that of centers using different surgical approaches and indicates that neocorticectomy is a suitable procedure in a highly selected population even when limited resources are available.

Adaptation, Psychological↗