Aircraft noise exposure and body mass index among female participants in two Nurses' Health Study prospective cohorts living around 90 airports in the United States

OBJECTIVE

Aircraft noise exposure is linked to cardiovascular disease risk. One understudied candidate pathway is obesity. This study investigates the association between aircraft noise and obesity among female participants in two prospective Nurses' Health Study (NHS and NHSII) cohorts.

METHODS

Aircraft day-night average sound levels (DNL) were estimated at participant residential addresses from modeled 1 dB (dB) noise contours above 44 dB for 90 United States (U.S.) airports in 5-year intervals 1995-2010. Biennial surveys (1994-2017) provided information on body mass index (BMI; dichotomized, categorical) and other individual characteristics. Change in BMI from age 18 (BMI18; tertiles) was also calculated. Aircraft noise exposures were dichotomized (45, 55 dB), categorized (<45, 45-54, ≥55 dB) or continuous for exposure ≥45 dB. Multivariable multinomial logistic regression using generalized estimating equations were adjusted for individual characteristics and neighborhood socioeconomic status, greenness, population density, and environmental noise. Effect modification was assessed by U.S. Census region, climate boundary, airline hub type, hearing loss, and smoking status.

RESULTS

At baseline, the 74,848 female participants averaged 50.1 years old, with 83.0%, 14.8%, and 2.2% exposed to <45, 45-54, and ≥55 dB of aircraft noise, respectively. In fully adjusted models, exposure ≥55 dB was associated with 11% higher odds (95% confidence interval [95%CI]: -1%, 24%) of BMIs ≥30.0, and 15% higher odds (95%CI: 3%, 29%) of membership in the highest tertile of BMI18 (ΔBMI 6.7 to 71.6). Less-pronounced associations were observed for the 2nd tertile of BMI18 (ΔBMI 2.9 to 6.6) and BMI 25.0-29.9 as well as exposures ≥45 versus <45 dB. There was evidence of DNL-BMI trends (ptrends ≤ 0.02). Stronger associations were observed among participants living in the West, arid climate areas, and among former smokers.

DISCUSSION

In two nationwide cohorts of female nurses, higher aircraft noise exposure was associated with higher BMI, adding evidence to an aircraft noise-obesity-disease pathway.

Associations between long-term aircraft noise exposure, cardiovascular disease, and mortality in US cohorts of female nurses

There is limited research examining aircraft noise and cardiovascular disease (CVD) risk. The objective of this study was to investigate associations of aircraft noise with CVD among two US cohorts, the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII).

Methods

Between 1994 and 2014, we followed 57,306 NHS and 60,058 NHSII participants surrounding 90 airports. Aircraft noise was modeled above 44 A-weighted decibels (dB(A)) and linked to geocoded addresses. Based on exposure distributions, we dichotomized exposures at 50 dB(A) and tested sensitivity of this cut-point by analyzing aircraft noise as categories (<45, 45-49, 50-54, ≥55) and continuously. We fit cohort-specific Cox proportional hazards models to estimate relationships between time-varying day-night average sound level (DNL) and CVD incidence and CVD and all-cause mortality, adjusting for fixed and time-varying individual- and area-level covariates. Results were pooled using random effects meta-analysis.

Results

Over 20 years of follow-up, there were 4529 CVD cases and 14,930 deaths. Approximately 7% (n = 317) of CVD cases were exposed to DNL ≥50 dB(A). In pooled analyses comparing ≥50 with <50 dB(A), the adjusted hazard ratio for CVD incidence was 1.00 (95% confidence interval: 0.89, 1.12). The corresponding adjusted hazard ratio for all-cause mortality was 1.02 (95% confidence interval: 0.96, 1.09). Patterns were similar for CVD mortality in NHS yet underpowered.

Conclusions

Among participants in the NHS and NHSII prospective cohorts who generally experience low exposure to aircraft noise, we did not find adverse associations of aircraft noise with CVD incidence, CVD mortality, or all-cause mortality.

Gold Standard Cholera Diagnostics Are Tarnished by Lytic Bacteriophage and Antibiotics

A fundamental, clinical, and scientific concern is how lytic bacteriophage, as well as antibiotics, impact diagnostic positivity. Cholera was chosen as a model disease to investigate this important question, because cholera outbreaks enable large enrollment, field methods are well established, and the predatory relationship between lytic bacteriophage and the etiologic agent Vibrio cholerae share commonalities across bacterial taxa. Patients with diarrheal disease were enrolled at two remote hospitals in Bangladesh. Diagnostic performance was assessed as a function of lytic bacteriophage detection and exposure to the first-line antibiotic azithromycin, detected in stool samples by mass spectrometry. Among diarrheal samples positive by nanoliter quantitative PCR (qPCR) for V. cholerae (n = 78/849), the odds that a rapid diagnostic test (RDT) or qPCR was positive was reduced by 89% (odds ratio [OR], 0.108; 95% confidence interval [CI], 0.002 to 0.872) and 87% (OR, 0.130; 95% CI, 0.022 to 0.649), respectively, when lytic bacteriophage were detected. The odds that an RDT or qPCR was positive was reduced by more than 99% (OR, 0.00; 95% CI, 0.00 to 0.28) and 89% (OR, 0.11; 95% CI, 0.03 to 0.44), respectively, when azithromycin was detected. Analysis of additional samples from South Sudan found similar phage effects on RDTs; antibiotics were not assayed. Cholera burden estimates may improve by accommodating for the negative effects of lytic bacteriophage and antibiotic exposure on diagnostic positivity. One accommodation is using bacteriophage detection as a proxy for pathogen detection. These findings have relevance for other diagnostic settings where bacterial pathogens are vulnerable to lytic bacteriophage predation.

Horizontal and vertical distribution of sea lice larvae (Lepeophtheirus salmonis) in and around salmon farms in the Bay of Fundy, Canada

The sea louse, Lepeophtheirus salmonis, is parasitic to salmonid species in the Northern Hemisphere and has become a widespread biological and economic problem for the salmon farming industry. A better understanding is needed of their spatial distribution and early life history to disrupt the life cycle of the sea louse. In this study, sea lice larval densities within salmon farms, between salmon farms and reference sites, and at various depths were quantified using both plankton pumps and plankton nets. Farm sites exhibited significantly higher densities than reference sites; however, these densities dropped an order of magnitude at a distance of 100 m from the cages. The majority of the larvae captured in the study were nauplii (93%), and densities ranged from 0 to 10 larvae/m³ . Free-swimming sea lice larvae were found to exhibit a diel cycle where nauplii larvae were in deeper waters (10-17 m) during the day and in surface waters (1-6 m) during the night. The results of this study suggest that the early life-history stages of sea lice originate from and may remain close to active salmon farms, creating a self-sustaining population.

Emerging technologies to measure neighborhood conditions in public health: implications for interventions and next steps

Adverse neighborhood conditions play an important role beyond individual characteristics. There is increasing interest in identifying specific characteristics of the social and built environments adversely affecting health outcomes. Most research has assessed aspects of such exposures via self-reported instruments or census data. Potential threats in the local environment may be subject to short-term changes that can only be measured with more nimble technology. The advent of new technologies may offer new opportunities to obtain geospatial data about neighborhoods that may circumvent the limitations of traditional data sources. This overview describes the utility, validity and reliability of selected emerging technologies to measure neighborhood conditions for public health applications. It also describes next steps for future research and opportunities for interventions. The paper presents an overview of the literature on measurement of the built and social environment in public health (Google Street View, webcams, crowdsourcing, remote sensing, social media, unmanned aerial vehicles, and lifespace) and location-based interventions. Emerging technologies such as Google Street View, social media, drones, webcams, and crowdsourcing may serve as effective and inexpensive tools to measure the ever-changing environment. Georeferenced social media responses may help identify where to target intervention activities, but also to passively evaluate their effectiveness. Future studies should measure exposure across key time points during the life-course as part of the exposome paradigm and integrate various types of data sources to measure environmental contexts. By harnessing these technologies, public health research can not only monitor populations and the environment, but intervene using novel strategies to improve the public health.

In vitro evaluation of prestorage pooled leukoreduced whole blood-derived platelets stored for up to 7 days

BACKGROUND

Advantages to storing whole blood-derived platelets (PLTs) as a pool for 7 days would include operational efficiencies and facilitation of bacterial testing and pathogen inactivation. The in vitro quality of pre-storage pooled PLTs stored for up to 7 days was assessed.

STUDY DESIGN AND METHODS

Leukoreduced PLTs were pooled before storage (5 units/pool) and stored for either 5 or 7 days. Samples were collected at the time of pooling and either on Day 5 (n=16-29) or on Day 7 (n=4-30) and tested for biochemical and activation markers and morphology and/or shape change. Control PLTs were stored individually for 5 or 7 days and then tested as indicated above.

RESULTS

The mean PLT counts (x10(9)/L) were similar: control PLTs, 1344 (464 SD); and prestorage pooled PLTs, 1327 (220 SD; p=0.93). On Day 5, the pH value was significantly lower (p<or=0.0001) for the prestorage pooled PLTs. Lactate and partial pressure of O2 (pO2) were significantly higher (p<or=0.003). On Day 7 of storage, significant differences were noted with pH, pCO2, and hypotonic shock all being lower with the prestorage pooled product, whereas pO2, lactate, and morphology scores were higher (p values all <0.03). Although significant differences were found, the magnitude of the difference would not be expected to impact on transfusion outcomes.

CONCLUSION

These results suggest that prestorage pooled PLTs can be stored for up to 7 days; however, studies are needed to ensure that the clinical benefit of PLTs stored as a pool is not inferior to those stored individually.

Assessing the effectiveness of whole blood-derived platelets stored as a pool: a randomized block noninferiority trial

BACKGROUND

Prestorage pooling of whole blood-derived platelets (PLTs) would simplify bacterial detection. This study evaluated the in vivo effect of the prestorage pooling of PLTs stored for up to 5 days, by assessing the corrected count increment (CCI) 18 to 24 hours after transfusion of the product.

STUDY DESIGN AND METHODS

A randomized block noninferiority design was used. Eligible patients had chemotherapy-induced thrombocytopenia and were considered likely to need at least six PLT transfusions. For every block of two transfusion events, one consisted of PLTs stored individually and then pooled before transfusion, and the other was a product pooled before storage. The primary outcome was categorized as a successful (>4.5) or unsuccessful (<or=4.5) 18- to 24-hour posttransfusion CCI analyzed with a matched pair score test. A mixed-effect linear model estimated the mean difference in CCI between the two types of storage.

RESULTS

Twenty-three eligible patients received a total of 189 PLT transfusions. The median number of PLT transfusions was 7 (range, 0-27). Eighty-five complete transfusion pairs were used in the primary analysis. The proportions of transfusions leading to a CCI of greater than 4.5 was identical for both routine and PLTs pooled before storage (45/85=52.9%; relative risk, 1.00; lower limit of the one-sided 95% confidence interval [CI], 0.83). The estimate of the mean difference in CCI between pooled and routine storage (pooled-routine) was -0.45 (95% CI, -2.23 to 1.33; p=0.63).

CONCLUSION

These results provide evidence that storage of PLTs as a pool for up to 5 days results in posttransfusion CCIs that are not inferior to PLTs stored individually.

Hybridization and bond-orbital components in site-specific X-ray photoelectron spectra of rutile TiO2

We have determined the Ti and O components of the rutile TiO2 valence band using the method of site-specific x-ray photoelectron spectroscopy. Comparisons with calculations based on pseudopotentials within the local density approximation reveal the hybridization of the Ti 3d, 4s, and 4p states, and the O 2s and 2p states on each site. These chemical effects are observed due to the large differences between the angular-momentum dependent matrix elements of the photoelectron process.

Sustained release of silver from periodontal wafers for treatment of periodontitis

Periodontal wafers intended to treat the underlying infections in patients with periodontitis have been developed. The wafers consist of poly(lactic-co-glycolic acid) as a primary bioerodible polymeric component, poly(ethylene glycol) as a plasticizer and encapsulation aid, and silver nitrate as the antimicrobial agent. The wafers are capable of sustained in vitro release of bioactive silver for at least 4 weeks. The wafers exhibit silver release that follows erosion kinetics, confirming a bulk erosion/release mechanism. In clinical evaluation, sustained release of silver at bactericidal levels for at least 21 days is observed. Staining of hard and soft tissues due to the released silver is minimal and reversible.

A comparison of prestorage WBC-reduced whole-blood-derived platelets and bedside-filtered whole-blood-derived platelets in autologous progenitor cell transplant

BACKGROUND

Prestorage WBC-reduced platelet concentrates (PCs) can be manufactured from platelet-rich plasma (PRP) by in-line filtration of PRP. There are few published data on the clinical use of these products, as compared to bedside-filtered pools of standard PCs (S-PCs) manufactured from PRP.

STUDY DESIGN AND METHODS

A prospective, randomized trial was conducted in autologous progenitor cell transplant patients requiring platelet transfusions with each patient as his or her own control who was given a pool of 5 units of WBC-reduced PCs and a pool of 6 units of S-PCs within a 3-hour period. The pools were characterized before transfusion for platelet and WBC content, P-selectin expression, and IL-8. The patients were monitored with platelet counts and vital signs and observed for reactions. Data were analyzed using Mann-Whitney U tests.

RESULTS

Thirty-three transfusions were administered to 13 patients. Median platelet content in the WBC-reduced PC pools was lower than that in the S-PC pools (3.3 vs. 4.0 x 10(11), p<0.01). Median WBC content was 4 to 5 log less in the WBC-reduced PC pools (2.5 x 10(4) vs. 4.6 x 10(8), p<0.01). Median IL-8 levels (pg/mL) were lower in the WBC-reduced PC pools (2 vs. 36, p<0.01). No differences were observed in CCI, but the median absolute increase after transfusion of the S-PC pools was higher (25 vs. 19 x 10(9)/L, p<0.01), which reflected the larger size of the S-PC pools. No overall differences in vital signs were recorded. Two reactions were observed, both in temporal association with the transfusion of pools of S-PCs.

CONCLUSIONS

A pool consisting of 5 units of WBC-reduced PCs gave a median platelet increment of 19 x 10(9) per L in these thrombocytopenic patients and has a median WBC content 1 to 2 log below the accepted threshold for primary alloimmunization or CMV transmission.

Direct measurement of valence-charge asymmetry by x-ray standing waves

By monitoring valence-photoelectron emission under condition of strong x-ray Bragg reflection, we have determined that a majority of GaAs valence charge resides on the anion sites of this heteropolar crystal, in quantitative agreement with the GaAs bond polarity as calculated from the Hartree-Fock term values. In contrast, the valence-charge distribution in Ge is found to be symmetric. In both cases, the valence emission is found to be closely coupled to the atomic cores.

Role of protein kinase C in ethanol-induced activation of adenylyl cyclase

Ethanol is known to enhance the activity of adenylyl cyclase (AC) in a number of cells and tissues. Recent work has suggested that the various isoforms of AC show differential sensitivity to ethanol, with Type VII AC being most sensitive. However, the mechanism of action of ethanol is unclear. In the present work, we investigated the effect of ethanol on AC activity in the human erythroleukemia (HEL) cell line, platelets, and AC VII-transfected HEK 293 cells. The HEL cells contain abundant amounts of mRNA for Type VII AC. We found that both ethanol and phorbol dibutyrate (PDBu) treatment enhanced agonist (prostaglandin E1; PGE1)-stimulated AC activity in HEL cells, as well as in platelets and HEK 293 cells transfected with AC VII. Inhibitors of protein kinase C (PKC) blocked the stimulatory effects of both ethanol and PDBu. However, the effects of ethanol and PDBu on AC activity were additive, suggesting that the mechanisms of action of ethanol and PDBu were not identical. Furthermore, a 30-min exposure of HEL cells to ethanol attenuated (desensitized) the ability of ethanol, but not PDBu, to enhance agonist-activated AC activity. On the other hand, a 30-min pretreatment with PDBu attenuated the AC response to the phorbol ester, but not to ethanol; but, after a 20 hr preincubation with phorbol ester, the ability of both PDBu and ethanol to enhance prostaglandin E1-stimulated AC activity was completely eliminated. Finally, pretreatment of HEL cells with pertussis toxin blocked the effect of PDBu, but not ethanol, on AC activity. The results support the involvement of phorbol ester-sensitive PKC(s) in ethanol's enhancement of agonist-activated activity of AC in HEL cells, but suggest that the mechanism of ethanol's action is different from that of PDBu. The findings with pertussis toxin suggest that PDBu activation of PKC(s) may affect AC activity through phosphorylation of a G1 protein, whereas ethanol may act by promoting phosphorylation of a different substrate (e.g., AC VII).

Fluorescence methods to assess multidrug resistance in individual cells

PURPOSE

Microscopic methods to measure the activity of drug extrusion systems important in multidrug resistance in individual cells were developed.

METHODS

Multidrug-resistant (MDR) and parental lines of hamster CHO and pituitary GH3 cells were incubated with the acetoxymethylester (AM) forms of several fluorescent calcium-sensing dyes, fura2, indo1 and fluo3. The AM forms of these compounds are hydrolyzed by intracellular esterases and then trapped in cells, and the AM forms of the dyes are excellent substrates for P-glycoprotein (Pgp).

RESULTS

The fluorescent free acid forms of fura2, indol and fluo3 did not accumulate in MDR lines unless a chemosensitizer such as cyclosporin A, R(+)verapamil, quinidine, or progesterone was included during loading to prevent the cells from extruding the AM forms of the dyes before they could be hydrolyzed. Cyclosporin A increased the fluorescence due to intracellularly trapped fura2 free acid from 8- to 20-fold and was maximally effective at < 5 microM. Fluorescence microscopy was employed to measure fura2 free acid accumulation by parental and MDR cell lines using excitation at the Ca2+-insensitive wavelength. When MDR cells were incubated with rhodamine 123 and fura2/AM, no fluorescence was detectable. Cellular fluorescence was dramatically increased by inclusion of cyclosporin A, quinidine, progesterone, or R(+)verapamil. There was no measurable decline in the fura2 free acid fluorescence in 1 h while the fluorescence due to rhodamine 123 diminished rapidly in cells overexpressing Pgp.

CONCLUSIONS

These fluorescence methods detect drug-extruding activity in individual cells and therefore have the potential to provide complementary information to studies quantifying protein or mRNA levels of Pgp or other efflux pumps. In addition, they provide a rapid and quantifiable method for screening multidrug resistance reversing agents.

Characterization of the calcium response to thyrotropin-releasing hormone in lactotrophs and GH cells

Thyrotropin-releasing hormone (TRH) acts via a G-protein-coupled receptor on lactotrophs to increase the intracellular free calcium ion concentration, [Ca(2+)](i). The [Ca(2+)](i) response depends on both TRH concentration and the duration of TRH exposure. An initial, short-lived [Ca(2+)](i) spike results from release of Ca(2+) from intracellular stores, whereas a later sustained [Ca(2+)](i) increase, often characterized by [Ca(2+)](i) oscillations, results from an influx of extracellular Ca(2+) through both voltage-gated and non-voltage-gated, store-operated Ca(2+) channels. The initial spike phase predominates at high doses of TRH, whereas the plateau phase predominates at low doses. The mechanisms underlying the complex [Ca(2+)](i) response to TRH are discussed.

Continuous gastric suctioning decreases measured esophageal temperature during general anesthesia

OBJECTIVE

This study sought to determine whether continuous gastric suctioning influences esophageal temperature measurements.

METHODS

This study evaluated 21 patients scheduled for extremity or lower abdominal surgery. After induction of general endotracheal anesthesia, an orogastric tube, and esophageal and nasopharyngeal temperature probes were placed in functional positions. Baseline esophageal (Tes) and nasopharyngeal (Tnas) temperatures were recorded and the orogastric tube was placed on continuous suction. After the first 11 patients (Group I) were studied, 10 additional patients (Group II) were studied with more frequent data collection to improve the time resolution of temperature changes. Temperatures were recorded for patients in Group I at 2 and 10 min with suctioning and 10 min after cessation of suctioning. In Group II, temperatures were recorded at 1, 2, 5 and 10 min with suctioning and 10 min after cessation of suctioning. Analysis of data was performed using repeated measures analysis of variance and paired t-tests with the Bonferroni correction.

RESULTS

In Group I, Tes decreased significantly from 35.9 +/- 0.2 degrees C (mean +/- SE) to 35.1 +/- 0.4 degrees C at 2 min and 34.8 +/- 0.3 degrees C at 10 min of suctioning (p < 0.01). Ten minutes after cessation of suctioning, Tes was not significantly different from the baseline measurement. Tnas did not change significantly over the 20 min observation period. In Group II, Tes continually decreased from 36.2 +/- 0.1 degrees C to 34.8 +/- 0.3 degrees C after 10 min of suctioning (p < 0.006) and returned to near baseline 10 min after cessation of suctioning. There was no significant change in Tnas over the 20 min observation period.

CONCLUSION

We conclude that continuous gastric suctioning decreases esophageal temperature measurements. This phenomenon should be recognized as an artifactual change in esophageal temperature and not a reflection of core temperature.

Visualization of the thyrotropin-releasing hormone receptor and its ligand during endocytosis and recycling

Endocytosis and recycling of both thyrotropin-releasing hormone (TRH) and its G-protein-coupled receptor were visualized by conventional and confocal fluorescence microscopy in pituitary cells using a rhodamine-labeled TRH analog (Rhod-TRH) and indirect immunofluorescent staining of cells stably transfected with an epitope-tagged TRH receptor (TRHR). The epitope-tagged TRHR was confined to the cell surface prior to agonist treatment. Both Rhod-TRH and TRHR were also localized on the plasma membrane after agonist binding at 0 degrees C. Ligand binding at 37 degrees C resulted in rapid endocytosis, and both Rhod-TRH and the epitope-tagged TRHR appeared in cytoplasmic vesicles within 5 min. Fluorescently labeled TRH and transferrin colocalized in the same endocytotic vesicles, and internalization of Rhod-TRH and TRHR was inhibited by hypertonic medium, suggesting that endocytosis occurred by a clathrin-dependent mechanism. Internalized TRHRs returned to the membrane within 20 min after removal of TRH, and cycloheximide did not block receptor recycling. A mutant TRHR truncated at Cys335 signaled but did not internalize Rhod-TRH, confirming the importance of the carboxyl terminus of the TRHR in receptor-mediated endocytosis. Thus, the TRH-TRHR complex is endocytosed via clathrin-coated vesicles and the receptor is recycled to the plasma membrane.

Thyrotropin-releasing hormone activates Ca2+ efflux. Evidence suggesting that a plasma membrane Ca2+ pump is an effector for a G-protein-coupled Ca(2+)-mobilizing receptor

These studies characterize the mechanisms involved in terminating the initial Ca2+ transient stimulated by thyrotropin-releasing hormone (TRH). When TRH was added to GH3 pituitary cells that had been treated with thapsigargin to block any agonist-stimulated increase in [Ca2+]i, TRH caused a decrease in [Ca2+]i. The Ca2+ clearing response was seen in pituitary GH3 cells and in nonexcitable HEK 293 cells transfected with TRH receptor cDNA, was evident at basal or elevated [Ca2+]i, and was mediated by the TRH receptor. The Ca2+ clearing response to TRH was not prevented by thapsigargin, Ca2+ ionophores, nimodipine, or replacement of extracellular Na+ but was inhibited by La3+. La3+ also increased the duration of the TRH-evoked [Ca2+]i transient. TRH-stimulated Ca2+ extrusion was directly demonstrated using extracellular fluo-3 free acid. TRH produced a 5-20-fold increase in Ca2+ efflux that was independent of extracellular Na+ and inhibited by vanadate. TRH stimulation of Ca2+ efflux was not reproduced by phorbol esters or inhibited by down-regulation of protein kinase C or staurosporine. The results suggest that agonist-activated Ca2+ efflux may be a universal component of an agonist-activated Ca2+ response and further suggest that a plasma membrane Ca2+ pump may be an effector for G-protein-coupled receptors linked to Ca2+ mobilization.

Characteristics of white cell-reduced red cells stored in tri-(2-ethylhexyl)trimellitate plastic

BACKGROUND

Standard blood storage containers contain extractable plasticizers that accumulate in blood during storage and are an unintended transfusion product. However, extractable plasticizers have a protective effect on the red cell membrane and improve red cell storage variables. Prestorage white cell reduction also improves selected red cell storage variables.

STUDY DESIGN AND METHODS

The study evaluated whether the beneficial effect of prestorage white cell reduction would offset the negative effect of the absence of extractable plasticizer in red cells stored in AS-3 for 42 days at 4 degrees C. Filtered red cells stored in polyvinylchloride containers with the nonextracting plasticizer, tri-(2-ethylhexyl)trimellitate (TEHTM), were compared to unfiltered red cells stored in polyvinylchloride containers with the extractable plasticizer di-(2-ethylhexyl)phthalate (DEHP).

RESULTS

Poststorage supernatant potassium and red cell osmotic fragility were significantly higher in white cell-reduced TEHTM units than in unfiltered DEHP units. The mean 24-hour recovery of the filtered TEHTM red cells was significantly lower than that of the unfiltered DEHP red cells (69.1 +/- 7.4% vs. 77.1 +/- 5.1%, p < 0.05, n = 8).

CONCLUSION

These data demonstrate that white cell reduction before 42-day storage in TEHTM containers with currently approved preservatives does not yield an acceptable red cell component.

Characteristics of the Ca2+ spike and oscillations induced by different doses of thyrotropin-releasing hormone (TRH) in individual pituitary cells and nonexcitable cells transfected with TRH receptor complementary deoxyribonucleic acid

The Ca2+ response of individual cells to TRH was investigated in excitable pituitary GH3 and in nonexcitable Hela cells transfected with the TRH receptor complementary DNA (HelaR cells). GH3 cells typically responded to 1 microM TRH with an immediate transient [Ca2+]i spike (mean peak [Ca2+]i = 1.5 microM) followed by a period of inactivity of approximately 100 sec long and then a secondary increase in [Ca2+]i with oscillations. At 10-100 nM TRH, the initial [Ca2+]i spike was more prolonged and immediately followed by a sustained elevation of [Ca2+]i. At 0.5-1 nM TRH, there was a variable lag before any response; the initial [Ca2+]i spike was absent or small, but the sustained phase was still present. The second phase of elevated [Ca2+]i, which could be eliminated with nimodipine or chelation of extracellular Ca2+, gave a bell-shaped TRH dose response curve. The effect of TRH on Ca2+ oscillations depended both on TRH concentration and the basal oscillation frequency. HelaR cells responded to 1 microM TRH with a rapid [Ca2+]i spike, and at less than or equal to 10 nM TRH, up to 50% of HelaR cells displayed agonist-induced sinusoidal [Ca2+]i oscillations independent of extracellular Ca2+. TRH never caused a sustained elevation of [Ca2+]i in HelaR cells. For GH3 and HelaR cells, the peak [Ca2+]i response increased with TRH concentration up to 1 microM. In contrast, the duration of the initial [Ca2+]i spike was shorter at higher TRH concentrations, decreasing from 16 to 6.3 s (GH3) or 92 to 35 s (HelaR) between 0.5 nM and 1 microM TRH. This shortening of the spike duration was caused by rapid clearing of cytoplasmic Ca2+ that depended primarily on agonist concentration. In summary, TRH stimulates a complex [Ca2+]i response pattern dependent upon both the agonist concentration and cell context. The initial burst of Ca2+ is cleared in part by agonist dependent Ca2+ clearing.

Inhibition of L-type calcium-channel activity by thapsigargin and 2,5-t-butylhydroquinone, but not by cyclopiazonic acid

Thapsigargin (TG), 2,5-t-butylhydroquinone (tBHQ) and cyclopiazonic acid (CPA) all inhibit the initial Ca(2+)-response to thyrotropin-releasing hormone (TRH) by depleting intracellular Ca2+ pools sensitive to inositol 1,4,5-trisphosphate (IP3). Treatment of GH3 pituitary cells for 30 min with 5 nM TG, 500 nM tBHQ or 50 nM CPA completely eliminated the TRH-induced spike in intracellular free Ca2+ ([Ca2+]i). Higher concentrations of TG and tBHQ, but not CPA, were also found to inhibit strongly the activity of L-type calcium channels, as measured by the increase in [Ca2+]i or 45Ca2+ influx stimulated by depolarization. TG and tBHQ blocked high-K(+)-stimulated 45Ca2+ uptake, with IC50 values of 10 and 1 microM respectively. Maximal inhibition of L-channel activity was achieved 15-30 min after drug addition. Inhibition by tBHQ was reversible, whereas inhibition by TG was not. TG and CPA did not affect spontaneous [Ca2+]i oscillations when tested at concentrations adequate to deplete the IP3-sensitive Ca2+ pool. However, 20 microM TG and 10 microM tBHQ blocked [Ca2+]i oscillations completely. The effect of drugs on calcium currents was measured directly by using the patch-clamp technique. When added to the external bath, 10 microM CPA caused a sustained increase in the calcium-channel current amplitude over 8 min, 10 microM tBHQ caused a progressive inhibition, and 10 microM TG caused an enhancement followed by a sustained block of the calcium current over 8 min. In summary, CPA depletes IP3-sensitive Ca2+ stores and does not inhibit voltage-operated calcium channels. At sufficiently low concentrations, TG depletes IP3-sensitive stores without inhibiting L-channel activity, but, for tBHQ, inhibition of calcium channels occurs at concentrations close to those needed to block agonist mobilization of intracellular Ca2+.

Regulation of L-type voltage-gated calcium channels by epidermal growth factor

GH3 rat pituitary cells have L-type voltage-gated calcium channels, and both the rate of uptake of 45Ca2+ and the concentration of intracellular free calcium ion ([Ca2+]i) are increased by depolarization with high potassium. Cells incubated for several days with 10 nM epidermal growth factor (EGF) responded to depolarization with a 30-65% smaller increase in 45Ca2+ uptake than untreated cells. The inhibitory response to EGF developed slowly, with a maximal effect requiring 24-48 h. EGF exerted a half-maximal reduction in depolarization-stimulated 45Ca2+ uptake at 0.1 nM and a maximal effect at 1-10 nM. 45Ca2+ uptake was reduced by EGF at strongly depolarized potentials (added K+, > 25 mM) with or without the calcium channel agonist BAY K8644. [Ca2+]i was measured using fura-2 before and after depolarization in control cells and cells incubated for 48 h with 10 nM EGF. EGF-treated cells responded to the addition of 30-50 mM KCl with a smaller increase in [Ca2+]i than control cells. Digital fluorescence imaging of individual fura-2-loaded cells confirmed that the average [Ca2+]i response to depolarization was lower in cells that had been incubated with EGF for 36 h. EGF treatment increased the amount of PRL secreted basally, but inhibited the acute PRL secretory response to depolarization with 50 mM KCl and 1 microM BAY K8644 from 2.6- to 1.5-fold. The results indicate that EGF reduces the activity of voltage-gated dihydropyridine-sensitive calcium channels on pituitary cells, and that this reduction in L-channel activity is accompanied by a smaller secretory response to depolarization.

Measurement of intracellular cadmium with fluorescent dyes. Further evidence for the role of calcium channels in cadmium uptake

Cellular uptake of Cd2+ has been monitored using intracellularly trapped dyes, Fura 2 and Quin 2, which bind Cd2+ with extremely high affinity, and digital fluorescence imaging has been used to visualize intracellular free Cd2+. The excitation spectrum of the Cd2+ complex of Fura 2 is similar to that of the Ca2+ complex, whereas Cd2+ displaces Ca2+ from Quin 2 and reduces fluorescence. Fluorescence of Fura 2-loaded cells increased when 50 microM extracellular Cd2+ was added and fluorescence of Quin 2-loaded cells decreased. Cd2+ uptake by GH3 pituitary cells, which occurs in part via voltage-sensitive L-type calcium channels, was increased by BAY K8644 and depolarization and decreased by nimodipine. When Fura 2 and Quin 2 were used to measure Cd2+ uptake by glial C6 cells, which have no L-channel activity, high K+ and BAY K8644 did not change the apparent rate of Cd2+ uptake. GH3 and C6 cells were incubated with Cd2+ for 24 h and loaded with Fura 2, and fluorescence was measured before and after addition of tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN), a membrane permeant chelator with extremely high affinity for metals. TPEN had little effect on fluorescence of Fura 2-loaded GH3 and C6 cells not exposed to Cd2+ but decreased fluorescence of cells that had been incubated with 1-10 microM Cd2+. Fluorescence ratio imaging of Fura 2-loaded cells was used to image intracellular free Cd2+ for both GH3 and C6 cells. Cd2+ uptake over 30-180 min could be followed by the increase in 340/380 fluorescence ratio and the increase in fluorescence ratio was reversed within 5 min by TPEN. The results provide further evidence for the importance of voltage-gated calcium channels to Cd2+ uptake of certain cells.

Improved post-transfusion quality of density separated AS-3 red cells after extended storage

A centrifugal method of red cell density separation was utilized for unit processing in these studies to determine the quality of the lighter fraction (neocytes) after storage for up to 42 d and to evaluate whether the heavier fraction (gerocytes) deteriorated more rapidly than neocytes during storage. Each unit was passed through a Leukotrap filter to remove white cells prior to density separation. Red cell recovery and survival were evaluated using double label technetium-99m with either chromium-51 or nonradioisotopic chromium which permitted concurrent paired analysis. In vivo neocyte red cell recovery, as tested on the same 11 donors on days 1, 7 and 42 of storage, was effectively unchanged. Recovery and survival half-life (that is, the number of days after transfusion at which half of the cells infused remain in the circulation) of 42 d stored gerocytes were significantly lower than similarly stored neocytes (75.5 +/- 7.2% and 20.1 +/- 6.5 d for gerocytes versus 84.4 +/- 4.9% and 39.0 +/- 9.0 d for neocytes). One-day stored neocytes showed a 16.5% increase in red cell availability over the combined average for 42 d stored neocytes and gerocytes. Statistically, while there were significantly higher ATP, 2,3-DPG, and lactate levels pre-storage by paired t-test for neocytes compared to gerocytes, by day 42 there were no significant differences detected between the two red cell fractions by any of the in vitro variables measured. These studies suggest that this simple separation technique for leucocyte-poor red cell units provides a neocyte population with improved viability and the potential for increased transfusion intervals in chronically transfused patients.

Prestorage removal of Yersinia enterocolitica from red cells with white cell-reduction filters

Prestorage removal of phagocytic white cells (WBCs) may increase the survivability of contaminating bacteria in units of stored red cells. Fourteen units of whole blood were inoculated with 65 colony-forming units per mL of Yersinia enterocolitica (serotype O:3) and processed into AS-3-preserved red cells. Five red cell units were filtered with a prototype third-generation filter and five red cell units with a second generation filter. WBC reduction was performed on the day of collection. Four red cell units were not filtered. Three noninoculated whole blood units served as negative controls; two were filtered (one with each type of WBC-reduction filter) and one remained unfiltered. All red cell units were then stored at 4 degrees C for 42 days. One of the five filtered red cell units (20%) in each filter group supported growth of Y. enterocolitica. In contrast, 4 (100%) of 4 unfiltered inoculated red cell units had growth (p = 0.04). Overall, 2 (20%) of 10 units of WBC-reduced red cells supported the growth of Y. enterocolitica, as compared to 100 percent of unfiltered red cell units after inoculation (p = 0.015). Bacterial contamination was not detected in any of the three noninoculated units. It can be concluded that prestorage WBC filtration significantly reduces the potential for growth of Y. enterocolitica in red cells stored at 4 degrees C for 42 days.

Characterization of multidrug-resistant pituitary tumor cells

These studies were designed to investigate the role of P-glycoprotein in an endocrine cell line. Drug-resistant pituitary cells were obtained by growing GH4C1 cells in the presence of increasing concentrations of colchicine. Cells resistant to colchicine at 0.4 micrograms/ml, termed GH4C1/RC.4, exhibited the multidrug-resistance phenotype, as the LD50 values for colchicine, puromycin, actinomycin D, and doxorubicin were between 8 and 30 times greater than the corresponding values for the parental GH4C1 cells. Verapamil at 10 microM increased the sensitivity of GH4C1/RC.4 cells to colchicine, puromycin, and actinomycin D, almost completely reversing the drug resistance. Flow cytometry and fluorescence microscopy were used to demonstrate that GH4C1/RC.4 cells retained less rhodamine 123 than GH4C1 cells, and that the rate of efflux of rhodamine 123 was much faster for GH4C1/RC.4 cells. Immunocytochemical staining with a monoclonal antibody, C219, to the 170-kilodalton P-glycoprotein showed directly that GH4C1/RC.4 cells overexpress P-glycoprotein. We used drug-resistant pituitary cells to assess the possible role of P-glycoprotein in uptake and efflux of several hormones. At equilibrium, GH4C1 and GH4C1/RC.4 cells bound similar amounts of [125I]L-triiodothyronine and [125I]L-thyroxine, and verapamil did not alter either equilibrium binding or thyroid hormone efflux kinetics. Multidrug-resistant GH4C1/RC.4 cells retained less [3H]hydrocortisone than parental GH4C1 cells at equilibrium, and verapamil increased the equilibrium concentration of [3H]hydrocortisone 3.6-fold. The effect of verapamil was due to its ability to reverse multidrug resistance, since two other chemosensitizers, quinidine and vinblastine, increased [3H]hydrocortisone retention as effectively as verapamil but another calcium channel blocker, nifedipine, had no effect. The drug-resistant GH4C1/RC.4 line synthesized more GH (290%) and much less PRL (5%) than the parent. Hydrocortisone stimulated GH synthesis and inhibited PRL similarly in GH4C1 and GH4C1/RC.4 cells. The results show that the GH4C1/RC.4 line is multidrug-resistant and overexpresses the 170-kilodalton P-glycoprotein and suggest that the P-glycoprotein pump contributes to hydrocortisone kinetics.

Visual identification of bacterially contaminated red cells

There have been increasing numbers of reports of transfusion-acquired Yersinia enterocolitica bacteremia (including several fatal cases). Fifteen units of whole blood were inoculated with various concentrations of Y. enterocolitica serotype 0:3 and processed into AS-3 preserved red cells (RBCs). Consistent growth of the organism was found at inoculum concentrations greater than or equal to 10 colony-forming units per mL. In all 13 units of RBCs that supported the growth of Y. enterocolitica, a darkening in color (due to hemolysis and a decrease in pO2) was observed in the bag. The attached sample segments, which were sealed from the main unit, remained sterile and did not darken. This color change was apparent in all the contaminated units by Day 35, which was 1.5 to 2 weeks after the bacteria were first detected in cultures of the blood. Hence, by comparison of the color of the segment tubing with that of the unit itself, units grossly contaminated with Y. enterocolitica can be identified prior to transfusion. Moreover, review of photographs on file at the Centers for Disease Control revealed this dramatic color change in 2 units of blood that caused transfusion-transmitted sepsis (Enterobacter agglomerans and an unidentified gram-negative bacillus, not Yersinia sp.), which demonstrated that the color change was not limited to Y. enterocolitica. This method of visual identification of contaminated units of blood could decrease the incidence of posttransfusion bacterial sepsis.

Randomized comparison of routine vs highly selective use of Doppler ultrasound and biophysical scoring to investigate high risk pregnancies

OBJECTIVE

To compare routine versus highly selective use of Doppler ultrasound and biophysical scoring in higher risk pregnancy.

DESIGN

A pragmatic randomized trial.

SETTING

St James's University Hospital, Leeds.

SUBJECTS

500 pregnant women at high risk of intrauterine growth retardation or still birth.

INTERVENTIONS

Regular monitoring with biophysical profile assessment and Doppler velocity waveform recording in umbilical and uteroplacental arteries. Results immediately available to clinicians.

MAIN OUTCOME MEASURES

Gestational age at delivery, obstetric intervention rates and short-term neonatal morbidity.

RESULTS

Risk factors were distributed very evenly between the 250 patients in the study and control groups respectively. A total of 902 biophysical profile and Doppler assessments were done in the 250 study group patients and only in 12 patients in the control group. In the study group, absent end-diastolic flow was found in only 2.7% of all 902 measurements. A persistently abnormal biophysical score was always associated with absence of end-diastolic flow. The mean gestational age at induction of labour was statistically and clinically similar in the two groups and there was no overall statistically significant difference in intervention rates between the two groups. There was a statistically significant lower frequency of depressed 5-min Apgar scores in the study group. Serious neonatal morbidity was also statistically significantly more common in the control group than in the study group.

CONCLUSIONS

The use of Doppler ultrasound in higher risk pregnancies does not lead to an increase in iatrogenic preterm delivery. The total rate of positive tests on Doppler ultrasound is very low and persistently abnormal biophysical scores are unlikely to be found in patients where umbilical end-diastolic blood flow is present. Surrogate measures for fetal damage seem to be improved when clinicians have access to Doppler ultrasound assessments.

Preparation of white cell-depleted red cells for 42-day storage using an integral in-line filter

A new blood pack system for the preparation of white cell-depleted red cells was studied. The system is a modified additive-solution quadruple-unit blood pack that incorporates a cellulose-acetate fiber depth filter in-line between the AS-3 additive bag and the CP2D collection bag. Mean +/- SD white cell removal from 156 units processed under standard production conditions was 97.7 +/- 2.7 percent; residual white cells were 1.1 +/- 1.0 x 10(8) per unit. Red cell loss was 10.0 +/- 1.0 percent (n = 43). Mean platelet removal was 80.9 percent from units from which platelet concentrates were not prepared (n = 47). Microaggregates did not form during storage, and hemolysis of filtered red cells was lower than that of unfiltered controls. Filtered AS-3 red cells stored for 42 days had a 51Cr survival of 80.1 +/- 5.7 percent (mean +/- SD) as compared with 78.9 +/- 6.2 percent for unfiltered controls (n = 17). This in-line filter system provides white cell-depleted, microaggregate-free red cells that can be stored for 42 days.

Beneficial effect of brief pre-transfusion incubation of platelets at 37 degrees C

The effects of brief warming of stored platelet concentrates were assessed in 15 children undergoing transfusion for stable thrombocytopenia due to chemotherapy (n = 13) or aplastic anaemia. Half of a pool of platelet concentrates stored at 22 degrees C was incubated at 37 degrees C for 1 hour and the other half at room temperature. Each patient received one bag of warmed and one of unwarmed cells transfused in random order 2 h apart. Platelet warming improved transfusion efficacy, as assessed on the basis of corrected platelet count increments (CCIs) and platelet morphology. Compared with unwarmed bags, warmed bags had a higher morphology score (p = 0.0001) and a higher CCI (adjusted for the transfusion order) at 1 h (n = 11; p = 0.014) and at 2 h (n = 15, p = 0.006) post transfusion. Thus, with platelets stored at room temperature bags warmed before transfusion to 37 degrees C for 1 h provide a larger number of circulating platelets after transfusion than do unwarmed bags.

Extended survival of neocytes produced by a new system

Red cells (RBCs) prepared by a new system using centrifugation to produce neocyte enrichment were studied in two laboratories. The system used a blood bag with a geometric configuration such that younger, less dense cells could be separated from older, denser cells. Phthalate ester density gradient curves determined that neocyte enrichment was 81.3 percent in one laboratory and 82 percent in the other. RBC viability was studied by 51Cr autologous transfusion in normal volunteer donors. A randomized, paired design was used in which each donor was transfused once each with neocytes and with RBCs of all ages. The mean control half-life was 34.8 +/- 5.4 days in one laboratory and 34.0 +/- 3.6 days in the other. The mean half-life of the neocyte-enriched RBCs was 45.2 +/- 8.2 days in one laboratory and 45.1 +/- 4.4 days in the other. This represented a more than 30 percent increase in half-life for the neocyte-enriched RBCs, a significant difference. This new system, a two-bag set that costs +15, allows the simple, efficient separation of neocyte-enriched RBCs that would have a longer half-life and could reduce the transfusion requirement in patients receiving chronic transfusion therapy.

Posttransfusion survival of red cells frozen for 8 weeks after 42-day liquid storage in AS-3

Current standards recommend that red cells (RBCs) should be frozen within 6 days of donation. There are situations, however, in which it is desirable to freeze RBCs that are older than 6 days, such as for the salvage of rare or autologous units. To determine the therapeutic efficacy of RBCs frozen after prolonged liquid storage, standard units were drawn from nine normal donors and stored at 4 degrees C for 42 days in a nutrient-additive solution, AS-3. 51CrRBC survival assays were performed (24-hour survival: 78.2 +/- 12.4%; n = 8) and the units were frozen at -80 degrees C in glycerol for 8 weeks. After deglycerolization, the mean RBC recovery was 81.0 +/- 4.1 percent and the mean 24-hour 51Cr survival was 78.0 +/- 9.1 percent. The index of therapeutic effectiveness (ITE) was determined by multiplying the postdeglycerolization 24-hour 51Cr survival by the mean RBC recovery (63.3 +/- 9.2). ITE values greater than 60 percent (75% 51Cr survival x 80% RBC recovery) were considered acceptable. Mean adenosine triphosphate levels declined from an initial 3.81 +/- 0.56 micromol per g of hemoglobin to 2.33 +/- 0.55 micromol per g after frozen storage. These findings show that an acceptable percentage of RBCs survives frozen storage after maximum liquid storage (mean ITE greater than 60%). If necessary, RBCs stored in AS-3 can be frozen at any time before 42 days.

Ascorbate-2-phosphate in red cell preservation. Clinical trials and active components

A red cell additive solution (AS-005) containing ascorbate-2-phosphate (AsP) to maintain 2,3-diphosphoglycerate, plus adenine, phosphate, and mannitol to retain viability and reduce hemolysis, was evaluated by human clinical trials. A crossover design was used with another additive solution (Nutricel AS-3, Cutter Laboratories) serving as the control for each donor. Each additive solution was evaluated at 35 and 42 days of storage. There was no significant difference between the red cell viability of the two storage solutions at either time period. Split-bag, AS-005 in vitro studies at two temperatures (2.5 and 5.5 degrees C), both within the range of 1 to 6 degrees C approved by the American Association of Blood Banks and the Food and Drug Administration, resulted in dramatically different in vitro parameters, including a threefold difference in 2,3-diphosphoglycerate (2,3-DPG), a fivefold difference in glucose, and significant differences in pH and adenosine triphosphate. High-pressure liquid chromatography data confirmed the preliminary report that 1 to 2 percent (wt/wt) oxalate was present in preparations of AsP. In vitro storage data confirmed that oxalate is the active component of AsP that preserves 2,3-DPG during storage.

Five-week red cell storage with preservation of 2,3 DPG

The 2,3 diphosphoglycerate (2,3 DPG) content of red cells stored in current anticoagulant-preservative products decreases rapidly after the first few days of storage, and by 3 weeks the red cells are essentially depleted of 2,3 DPG. Because ascorbic acid and ascorbate-2-phosphate (A-2-P) are effective in maintaining erythrocyte 2,3 DPG during liquid preservation, ascorbate was stabilized through autoclaving and subsequent storage by adding it as the trisodium salt of A-2-P to a phosphate-adenine-saline solution at a pH of 8.5 to 9.0. Red cell concentrates prepared from blood drawn into citrate-phosphate-double-dextrose were supplemented with the A-2-P additive solution (AS-4) and studied in vitro and in vivo. Mean 2,3 DPG values for 22 units were 147.6, 113.5, and 82.3 percent of initial value after storage for 3, 4, and 5 weeks, respectively. Maintenance of 2,3 DPG was at the expense of adenosine triphosphate (ATP), which fell to as low as 22.2 percent of initial value after 5 weeks. Despite the low ATP values, the 24 hour 51Cr-labeled red cell recoveries averaged 80.8 and 74.1 percent after 4 and 5 weeks of storage, respectively. The AS-4 system provides a red cell product with acceptable viability and improved oxygen off-loading function.

Effects of AS-3 nutrient-additive solution on 42 and 49 days of storage of red cells

Storage of red blood cells in a nutrient-additive solution, AS-3 (Nutricel, Cutter Biological, Berkeley, CA), was evaluated after 42 and 49 days of storage by in vitro measurements of hemolysis, adenosine triphosphate (ATP) levels, glucose levels and other constituents, and in vivo study of 24-hour survival of autologous, reinfused red cells labeled with 51Cr with and without 125I human serum albumin. Two laboratories conducted the studies independently. After 42 days of storage, hemolysis was within an acceptable range (0.72 +/- 0.4% and 1 +/- 0.2%), ATP decreased to 61 percent and 56 percent in the two laboratories, and 24-hour survivals were 85.1 +/- 8.3 percent for single-label cells in one laboratory and 82.8 +/- 10 percent (single-label cells) and 84.1 +/- 13.1 percent (double-label cells) in the second laboratory. Thus, results for single- and double-label cells were similar. After 49 days of storage, ATP fell to 45 and 46 percent in the two laboratories. Twenty-four-hour recovery fell to 69.4 +/- 7.4 percent with single-label cells and to 68.2 +/- 6.7 percent with double-label cells in one laboratory. In the other laboratory, a paired study comparing AS-3 with the already approved AS-1 solution (Adsol; Fenwal Laboratories, Deerfield, IL) showed nearly identical 24-hour survivals of 71.9 +/- 8.8 percent in Nutricel and 71.8 +/- 6.5 percent in Adsol. These studies demonstrate the excellent viability of the new solution after 42 days of study. At 49 days of study, viability decreased significantly and was comparable in the two nutrient-additive solutions studied. The value of paired comparison study is demonstrated by the latter results.

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.

pH changes caused by bacterial growth in contaminated platelet concentrates

While platelet concentrates are stored at room temperature, lactic and other acids are produced and the pH decreases as the buffering capacity of the plasma is exhausted. Platelet viability will be compromised if the pH decreases to pH 6.0 and below. Similarly, a pH decrease can be produced also by bacterial contamination if the organisms produce acid as an end product. Thus the determination of pH could serve as a sensitive indicator of bacterial contamination. This hypothesis was tested by us by inoculating known organisms into platelet concentrations. It was found that the pH may decrease, may remain unchanged, or, in a few cases, even increase. Visual signs of contamination could be observed but not consistently enough to be entirely dependable. Therefore, this method does not appear to detect bacterial contamination reliably in platelet concentrates.

Preservation of red cell antigens during storage of blood with different anticoagulants

A major concern when storing blood is that the antigens of the red cells will lose some of their reactivity in vitro. As part of a study of blood stored in newer anticoagulants, we tested the persistence of the ABO, Rh, Lewis, and P antigens. Blood was stored for 21 to 35 days in several anticoagulant-preservative systems, such as citrate-phosphate-dextrose and several additive solutions, while using bags of polyvinyl chloride plasticized with di(2-ethyl hexyl) phthalate or tri (2-ethyl hexyl) trimellitate. No significant loss of antigenicity occurred in the ABO and Rh systems, but antigens in the Lewis and P systems lost some reactivity during storage.

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.

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.

The surgeon, genetics, and cancer control: the Cancer Family Syndrome

A family manifesting the Cancer Family Syndrome has been evaluated extensively from the medical and genetic standpoint. Findings of excess occurrence of carcinoma of the colon and endometrium, multiple primary cancer, early age of onset, and autosomal dominant mode of genetic transmission mandate a program of increased surveillance and cancer education. Prophylactic surgical implications are provided for certain of these enormously high cancer risk patients.