Safety and acceptability of intravaginal rings releasing estradiol and progesterone

OBJECTIVE

This study aimed to evaluate the safety and acceptability of two fixed-dose 28-day vaginal ring formulations of 17β-estradiol (E2) and progesterone (P4) to treat vasomotor symptoms (VMS) and the genitourinary syndrome of menopause.

DESIGN

DARE HRT1-001 was the first-in-woman study of 28-day exposure to two 28-day intravaginal rings (IVRs) designed to release 80 µg/day E2 + 4 mg/day P4 (IVR1) or 160 µg/day E2 + 8 mg/day P4 (IVR2) compared with oral E2 1 mg/day + oral P4 100 mg/day. To assess safety, participants completed a daily diary to record treatment emergent adverse events (TEAEs). To determine acceptability, at the end of treatment IVR users completed a questionnaire assessing tolerability and usability.

RESULTS

Enrolled women (n = 34) were randomized to use IVR1 (n = 10), IVR2 (n = 12) or oral (n = 12). Thirty-one participants (IVR1 = 10, IVR2 = 10, oral = 11) completed the study. The TEAE profile of those in the IVR groups were similar to the referent oral regimen. TEAEs related to the study product were more common with IVR2 use. Endometrial biopsies were not performed unless endometrial thickness was >4 mm or for clinically significant postmenopausal bleeding. One IVR1 participant had an endometrial stripe increase from 4 mm at screening to 8 mm at the end of treatment. The biopsy indicated no evidence of plasma cells or endometritis and no evidence of atypia, hyperplasia or malignancy. Two other endometrial biopsies were performed for postmenopausal bleeding with similar findings. There were no clinically meaningful laboratory or vital sign abnormalities or trends identified in observed values or changes from baseline. Pelvic speculum examination identified no clinically significant abnormalities in any participant at any visit. Tolerability and usability data demonstrated that both IVRs were generally highly acceptable.

CONCLUSIONS

Both IVR1 and IVR2 were safe and well tolerated in healthy postmenopausal women. TEAE profiles were comparable to the referent oral regimen.

Factors associated with registered nurses' academic performance in advanced practice nursing preparatory education: A retrospective cohort study

AIM

To explore factors associated with academic performance in the Master of Nursing programme.

BACKGROUND

Advanced practice nursing preparatory education generally involves completion of the Master of Nursing programme. While prior clinical experiences and on-the-job training are believed to underpin the preparation for such education, studies have suggested only weak or no associations between nurses' academic success in graduate schools and their clinical experiences.

METHODS

A retrospective cohort study was conducted in the nursing department of a university in Singapore. Academic and demographic data were extracted in February 2020 from a shared repository of anonymised teaching and learning data. R was used to select and merge data tables into a usable format for subsequent analysis. Students enrolled between 2010 and 2017 were included for the analysis (n = 246).

RESULTS

Age was statistically significantly associated with overall cumulative academic performance (p < 0.001). Younger students on average academically outperformed older students. Unmarried students were associated with better cumulative academic performance in the Clinical Practicum 2 module (p = 0.018).

CONCLUSION

Younger students have historically outperformed their older counterparts in the Master of Nursing programme. There is a need to reassess the requirement of five years of clinical experience as an admission criterion for the Master of Nursing programme in Singapore.

IMPLICATIONS FOR NURSING POLICY

There is a need to re-evaluate the admission criteria to better engage and retain younger nurses interested in advanced nursing practice. Nursing educators and leaders can partner with academics to develop advanced practice-specific education for pre-master nurses with the aptitude and interest in pursuing this track.

Replicated Adsorption Technique used to Resolve ALX148 Interference in the Immunohematology Reference Laboratory

Introduction/Objective

Increased expression of CD47 by cancer cells inhibits macrophages' phagocytic activity through CD47-SIRPα interactions, allowing evasion of the innate immune system. Several drugs on the market have been developed to target this interaction, including monoclonal therapeutics and fusion proteins. ALX148 is a genetically engineered SIRPα fusion protein with an inactivated Fc portion. CD47 is expressed highly on red blood cells (RBC), resulting in strong interference in pre-transfusion compatibility testing of patients receiving ALX148. Consequently, trial patients are at increased risk of transfusion-related adverse events or delay of needed transfusion. Few resolutions of ALX148 interference to assess underlying alloantibody development have been reported. One such examiniation demonstrated x6 linear papain-treated RBC adsorptions removed ALX148 interference. This study aimed to replicate these findings.

Methods/Case Report

Three patients receiving combination ALX148 (dose 6.57-20mg/mL) and Azacitidine therapy with broad-reactive RBC antibody reactivity were selected. High volume alloadsorptions (8:1 RBC:plasma) were performed with papain-treated rr (ccdee) RBCs. Adsorptions were incubated at 37C for 10 minutes. Polyethylene glycol (PEG) was utilized in test tube indirect antiglobulin testing (IAT).

Results (if a Case Study enter NA)

Initial reactivity strength was 3-4+ at PEG-IAT and saline-IAT with a three-cell screening RBC reagent. Alloadsorbed plasma was non-reactive at IAT with a three-cell screening RBC reagent enhanced by PEG. Drug interference was removed following three times high volume papain-treated alloadsorption.

Conclusion

Cancer immunotherapies have transformed the standard of care in oncology. Despite the evident clinical success, the medical laboratory has been challenged with adapting to cancer drug therapies capable of causing interference in routine laboratory testing. Clinical trials of ALX148 are associated with interference in pre-transfusion compatibility testing. The use of extended phenotype matching for RBC transfusion can be utilized but incurs additional time and resources. These results suggest high volume linear papain RBC alloadsorptions may be incorporated into antibody resolution for patients receiving ALX148.

Periplasmic production of pernisine in Escherichia coli and determinants for its high thermostability

Pernisine is a subtilisin-like serine proteinase secreted by the hyperthermophilic archaeon Aeropyrum pernix. The significant properties of this proteinase are remarkable stability and ability to degrade the infectious prion proteins. Here we show the production of pernisine in the periplasm of Escherichia coli. This strategy prevented the aggregation of pernisine in the cytoplasm and increased the purity of the isolated pernisine. The thermostability of this recombinant pernisine was significantly increased compared with previous studies. In addition, several truncated pernisine variants were constructed and expressed in E. coli to identify the minimally active domain. The catalytic domain of pernisine consists of the αẞα structurally similar core flanked by the N-terminal and C-terminal outer regions. The deletion of the C-terminal α helix did not affect the pernisine activity at 90 °C. However, the complete deletion of the C-terminal outer region resulted in loss of proteolytic activity. The pernisine variant, in which the N-terminal outer region was deleted, had a reduced activity at 90 °C. These results underline the importance of the Ca²⁺ binding sites predicted in these outer regions for stability and activity of pernisine. KEY POINTS: • Aggregation of produced pernisine was prevented by translocation into periplasm. • Thermostability of mature pernisine was increased. • The outer regions of the catalytic core are required for pernisine thermostability.

Ultrarare variants drive substantial cis heritability of human gene expression

The vast majority of human mutations have minor allele frequencies under 1%, with the plurality observed only once (that is, 'singletons'). While Mendelian diseases are predominantly caused by rare alleles, their cumulative contribution to complex phenotypes is largely unknown. We develop and rigorously validate an approach to jointly estimate the contribution of all alleles, including singletons, to phenotypic variation. We apply our approach to transcriptional regulation, an intermediate between genetic variation and complex disease. Using whole-genome DNA and lymphoblastoid cell line RNA sequencing data from 360 European individuals, we conservatively estimate that singletons contribute approximately 25% of cis heritability across genes (dwarfing the contributions of other frequencies). The majority (approximately 76%) of singleton heritability derives from ultrarare variants absent from thousands of additional samples. We develop an inference procedure to demonstrate that our results are consistent with pervasive purifying selection shaping the regulatory architecture of most human genes.

Low intensity conduction states in FeS2: implications for absorption, open-circuit voltage and surface recombination

Pyrite (FeS2), being a promising material for future solar technologies, has so far exhibited in experiments an open-circuit voltage (OCV) of around 0.2 V, which is much lower than the frequently quoted 'accepted' value for the fundamental bandgap of ∼0.95 eV. Absorption experiments show large subgap absorption, commonly attributed to defects or structural disorder. However, computations using density functional theory with a semi-local functional predict that the bottom of the conduction band consists of a very low intensity sulfur p-band that may be easily overlooked in experiments because of the high intensity onset that appears 0.5 eV higher in energy. The intensity of absorption into the sulfur p-band is found to be of the same magnitude as contributions from defects and disorder. Our findings suggest the need to re-examine the value of the fundamental bandgap of pyrite presently in use in the literature. If the contribution from the p-band has so far been overlooked, the substantially lowered bandgap would partly explain the discrepancy with the OCV. Furthermore, we show that more states appear on the surface within the low energy sulfur p-band, which suggests a mechanism of thermalization into those states that would further prevent extracting electrons at higher energy levels through the surface. Finally, we speculate on whether misidentified states at the conduction band onset may be present in other materials.

Bacterial curli protein promotes the conversion of PAP248-286 into the amyloid SEVI: cross-seeding of dissimilar amyloid sequences

Fragments of prostatic acid phosphatase (PAP248-286) in human semen dramatically increase HIV infection efficiency by increasing virus adhesion to target cells. PAP248-286 only enhances HIV infection in the form of amyloid aggregates termed SEVI (Semen Enhancer of Viral Infection), however monomeric PAP248-286 aggregates very slowly in isolation. It has therefore been suggested that SEVI fiber formation in vivo may be promoted by exogenous factors. We show here that a bacterially-produced extracellular amyloid (curli or Csg) acts as a catalytic agent for SEVI formation from PAP248-286 at low concentrations in vitro, producing fibers that retain the ability to enhance HIV (Human Immunodeficiency Virus) infection. Kinetic analysis of the cross-seeding effect shows an unusual pattern. Cross-seeding PAP248-286 with curli only moderately affects the nucleation rate while significantly enhancing the growth of fibers from existing nuclei. This pattern is in contrast to most previous observations of cross-seeding, which show cross-seeding partially bypasses the nucleation step but has little effect on fiber elongation. Seeding other amyloidogenic proteins (IAPP (islet amyloid polypeptide) and Aβ1-40) with curli showed varied results. Curli cross-seeding decreased the lag-time of IAPP amyloid formation but strongly inhibited IAPP elongation. Curli cross-seeding exerted a complicated concentration dependent effect on Aβ1-40 fibrillogenesis kinetics. Combined, these results suggest that the interaction of amyloidogenic proteins with preformed fibers of a different type can take a variety of forms and is not limited to epitaxial nucleation between proteins of similar sequence. The ability of curli fibers to interact with proteins of dissimilar sequences suggests cross-seeding may be a more general phenomenon than previously supposed.

Alternative pathways of human islet amyloid polypeptide aggregation distinguished by (19)f nuclear magnetic resonance-detected kinetics of monomer consumption

Amyloid formation, a complex process involving many intermediate states, is proposed to be the driving force for amyloid-related toxicity in common degenerative diseases. Unfortunately, the details of this process have been obscured by the limitations in the methods that can follow this reaction in real time. We show that alternative pathways of aggregation can be distinguished by using (19)F nuclear magnetic resonance (NMR) to monitor monomer consumption along with complementary measurements of fibrillogenesis. The utility of this technique is demonstrated by tracking amyloid formation in the diabetes-related islet amyloid polypeptide (IAPP). Using this technique, we show IAPP fibrillizes without an appreciable buildup of nonfibrillar intermediates, in contrast to the well-studied Aβ and α-synuclein proteins. To further develop the usage of (19)F NMR, we have tracked the influence of the polyphenolic amyloid inhibitor epigallocatechin gallate (EGCG) on the aggregation pathway. Polyphenols have been shown to strongly inhibit amyloid formation in many systems. However, spectroscopic measurements of amyloid inhibition by these compounds can be severely compromised by background signals and competitive binding with extrinsic probes. Using (19)F NMR, we show that thioflavin T strongly competes with EGCG for binding sites on IAPP fibers. By comparing the rates of monomer consumption and fiber formation, we are able to show that EGCG stabilizes nonfibrillar large aggregates during fibrillogenesis.

Site specific interaction of the polyphenol EGCG with the SEVI amyloid precursor peptide PAP(248-286)

Recently, a 39 amino acid peptide fragment from prostatic acid phosphatase has been isolated from seminal fluid that can enhance infectivity of the HIV virus by up to 4-5 orders of magnitude. PAP(248-286) is effective in enhancing HIV infectivity only when it is aggregated into amyloid fibers termed SEVI. The polyphenol EGCG (epigallocatechin-3-gallate) has been shown to disrupt both SEVI formation and HIV promotion by SEVI, but the mechanism by which it accomplishes this task is unknown. Here, we show that EGCG interacts specifically with the side chains of monomeric PAP(248-286) in two regions (K251-R257 and N269-I277) of primarily charged residues, particularly lysine. The specificity of interaction to these two sites is contrary to previous studies on the interaction of EGCG with other amyloidogenic proteins, which showed the nonspecific interaction of EGCG with exposed backbone sites of unfolded amyloidogenic proteins. This interaction is specific to EGCG as the related gallocatechin (GC) molecule, which shows greatly decreased antiamyloid activity, exhibits minimal interaction with monomeric PAP(248-286). The EGCG binding was shown to occur in two steps, with the initial formation of a weakly bound complex followed by a pH dependent formation of a tightly bound complex. Experiments in which the lysine residues of PAP(248-286) have been chemically modified suggest the tightly bound complex is created by Schiff-base formation with lysine residues. The results of this study could aid in the development of small molecule inhibitors of SEVI and other amyloid proteins.

Biphasic effects of insulin on islet amyloid polypeptide membrane disruption

Type II diabetes, in its late stages, is often associated with the formation of extracellular islet amyloid deposits composed of islet amyloid polypeptide (IAPP or amylin). IAPP is stored before secretion at millimolar concentrations within secretory granules inside the β-cells. Of interest, at these same concentrations in vitro, IAPP rapidly aggregates and forms fibrils, yet within secretory granules of healthy individuals, IAPP does not fibrillize. Insulin is also stored within the secretory granules before secretion, and has been shown in vitro to inhibit IAPP fibril formation. Because of insulin's inhibitory effect on IAPP fibrillization, it has been suggested that insulin may also inhibit IAPP-mediated permeabilization of the β-cell plasma membrane in vivo. We show that although insulin is effective at preventing fiber-dependent membrane disruption, it is not effective at stopping the initial phase of membrane disruption before fibrillogenesis, and does not prevent the formation of small IAPP oligomers on the membrane. These results suggest that insulin has a more complicated role in inhibiting IAPP fibrillogenesis, and that other factors, such as the low pH of the secretory granule, may also play a role.

Role of zinc in human islet amyloid polypeptide aggregation

Human Islet Amyloid Polypeptide (hIAPP) is a highly amyloidogenic protein found in islet cells of patients with type II diabetes. Because hIAPP is highly toxic to beta-cells under certain conditions, it has been proposed that hIAPP is linked to the loss of beta-cells and insulin secretion in type II diabetics. One of the interesting questions surrounding this peptide is how the toxic and aggregation prone hIAPP peptide can be maintained in a safe state at the high concentrations that are found in the secretory granule where it is stored. We show here zinc, which is found at millimolar concentrations in the secretory granule, significantly inhibits hIAPP amyloid fibrillogenesis at concentrations similar to those found in the extracellular environment. Zinc has a dual effect on hIAPP fibrillogenesis: it increases the lag-time for fiber formation and decreases the rate of addition of hIAPP to existing fibers at lower concentrations, while having the opposite effect at higher concentrations. Experiments at an acidic pH which partially neutralizes the change in charge upon zinc binding show inhibition is largely due to an electrostatic effect at His18. High-resolution structures of hIAPP determined from NMR experiments confirm zinc binding to His18 and indicate zinc induces localized disruption of the secondary structure of IAPP in the vicinity of His18 of a putative helical intermediate of IAPP. The inhibition of the formation of aggregated and toxic forms of hIAPP by zinc provides a possible mechanism between the recent discovery of linkage between deleterious mutations in the SLC30A8 zinc transporter, which transports zinc into the secretory granule, and type II diabetes.

Utilization of Serine-Derivatized Gadonanotubes as Magnetic Nanoprobes for Intracellular Labeling of MCF-7 Human Breast Cancer Cell

The use of contrast agent enhances the image and gives a more accurate diagnosis by magnetic resonance imaging (MRI). However, safety of the patients with renal dysfunction raised the concern of increase in use. Comparing to the current clinical contrast agent gadopentetate dimeglumine (Gd-DTPA or Magnevist®), gadolinium-filled ultra-short carbon nanotubes (GNs) showed superior relaxivity. At different magnetic fields, GN increased relaxivity by 40-, 4.6- and 1.6-fold at magnetic fields of 1.5, 7 and 9.4T, respectively. More importantly, GN showed the ability in internalization that Gd-DTPA lacks. GN entered MCF-7 human breast cancer cells and allowed imaging of the cells by MRI. Detectable amount of gadolinium was found only in GN-treated MCF-7 cells by ICP-OES analysis. MRI of the kidney and liver showed GN was more dispersed suggesting that GN may be able to enter the interstitial space while Gd-DTPA was remained in the vasculature. Taken together, we found GN may be developed as a better contrast agent for MRI.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5005.

Three-dimensional structure and orientation of rat islet amyloid polypeptide protein in a membrane environment by solution NMR spectroscopy

Islet amyloid polypeptide (IAPP or amylin) is a 37-residue peptide hormone associated with glucose metabolism that is cosecreted with insulin by beta-cells in the pancreas. Since human IAPP is a highly amyloidogenic peptide, it has been suggested that the formation of IAPP amyloid fibers is responsible for the death of beta-cells during the early stages of type II diabetes. It has been hypothesized that transient membrane-bound alpha-helical structures of human IAPP are precursors to the formation of these amyloid deposits. On the other hand, rat IAPP forms transient alpha-helical structures but does not progress further to form amyloid fibrils. To understand the nature of this intermediate state and the difference in toxicity between the rat and human versions of IAPP, we have solved the high-resolution structure of rat IAPP in the membrane-mimicking detergent micelles composed of dodecylphosphocholine. The structure is characterized by a helical region spanning the residues A5 to S23 and a disordered C-terminus. A distortion in the helix is seen at R18 and S19 that may be involved in receptor binding. Paramagnetic quenching NMR experiments indicate that rat IAPP is bound on the surface of the micelle, in agreement with other nontoxic forms of IAPP. A comparison to the detergent-bound structures of other IAPP variants indicates that the N-terminal region may play a crucial role in the self-association and toxicity of IAPP by controlling access to the putative dimerization interface on the hydrophobic face of the amphipathic helix.

A single mutation in the nonamyloidogenic region of islet amyloid polypeptide greatly reduces toxicity

Islet amyloid polypeptide (IAPP or amylin) is a 37-residue peptide secreted with insulin by beta-cells in the islets of Langerhans. The aggregation of the peptide into either amyloid fibers or small soluble oligomers has been implicated in the death of beta-cells during type 2 diabetes through disruption of the cellular membrane. The actual form of the peptide responsible for beta-cell death has been a subject of controversy. Previous research has indicated that the N-terminal region of the peptide (residues 1-19) is primarily responsible for the membrane-disrupting effect of the hIAPP peptide and induces membrane disruption to a similar extent as the full-length peptide without forming amyloid fibers when bound to the membrane. The rat version of the peptide, which is both noncytotoxic and nonamyloidogenic, differs from the human peptide by only one amino acid residue: Arg18 in the rat version while His18 in the human version. To elucidate the effect of this difference, we have measured in this study the effects of the rat and human versions of IAPP(1-19) on islet cells and model membranes. Fluorescence microscopy shows a rapid increase in intracellular calcium levels of islet cells after the addition of hIAPP(1-19), indicating disruption of the cellular membrane, while the rat version of the IAPP(1-19) peptide is significantly less effective. Circular dichroism experiments and dye leakage assays on model liposomes show that rIAPP(1-19) is deficient in binding to and disrupting lipid membranes at low but not at high peptide to lipid ratios, indicating that the ability of rIAPP(1-19) to form small aggregates necessary for membrane binding and disruption is significantly less than hIAPP(1-19). At pH 6.0, where H18 is likely to be protonated, hIAPP(1-19) resembles rIAPP(1-19) in its ability to cause membrane disruption. Differential scanning calorimetry suggests a different mode of binding to the membrane for rIAPP(1-19) compared to hIAPP(1-19). Human IAPP(1-19) has a minimal effect on the phase transition of lipid vesicles, suggesting a membrane orientation of the peptide in which the mobility of the acyl chains of the membrane is relatively unaffected. Rat IAPP(1-19), however, has a strong effect on the phase transition of lipid vesicles at low concentrations, suggesting that the peptide does not easily insert into the membrane after binding to the surface. Our results indicate that the modulation of the peptide orientation in the membrane by His18 plays a key role in the toxicity of nonamyloidogenic forms of hIAPP.

A preliminary operational classification system for nonmutagenic modes of action for carcinogenesis

This article proposes a system of categories for nonmutagenic modes of action for carcinogenesis. The classification is of modes of action rather than individual carcinogens, because the same compound can affect carcinogenesis in more than one way. Basically, we categorize modes of action as: (1) co-initiation (facilitating the original mutagenic changes in stem and progenitor cells that start the cancer process) (e.g. induction of activating enzymes for other carcinogens); (2) promotion (enhancing the relative growth vs differentiation/death of initiated clones (e.g. inhibition of growth-suppressing cell-cell communication); (3) progression (enhancing the growth, malignancy, or spread of already developed tumors) (e.g. suppression of immune surveillance, hormonally mediated growth stimulation for tumors with appropriate receptors by estrogens); and (4) multiphase (e.g., "epigenetic" silencing of tumor suppressor genes). A priori, agents that act at relatively early stages in the process are expected to manifest greater relative susceptibility in early life, whereas agents that act via later stage modes will tend to show greater susceptibility for exposures later in life.

Quantitation of T-cell neogenesis in vivo after allogeneic bone marrow transplantation in adults

Following myeloablative therapy, it is unknown to what extent age-dependent thymic involution limits the generation of new T cells with a diverse repertoire. Normal T-cell receptor gene rearrangement in T-cell progenitors results in the generation of T-cell receptor rearrangement excision circles (TRECs). In this study, a quantitative assay for TRECs was used to measure T-cell neogenesis in adult patients with leukemia who received myeloablative therapy followed by transplantation of allogeneic hematopoietic stem cells. Although phenotypically mature T cells had recovered by 1 to 2 months after bone marrow transplantation (BMT), TREC levels remained low for 3 months after BMT. T-cell neogenesis became evident by 6 months, and normal levels of adult thymic function were restored at 6 to 12 months after BMT. Subsequent leukemia relapse in some patients was associated with reduced TREC levels, but infusion of mature donor CD4(+) T cells resulted in rapid restoration of thymic function. These studies demonstrate that T-cell neogenesis contributes to immune reconstitution in adult patients and suggest that thymic function can be manipulated in vivo. (Blood. 2001;98:1116-1121)

A method for the quantitative assessment of platelet-induced clot retraction and clot strength in fresh and stored platelets

BACKGROUND AND OBJECTIVES

The changes that occur in platelets as they undergo storage have been documented by aggregometry as well as by flow cytometry. However, one of the most essential platelet functions, the induction of clot retraction, has not been quantitatively assessed in stored platelets. We describe two potentially useful methods, platelet-induced clot retraction and clot strength, to assess effect of storage of platelets in blood banks or of platelet preparations subjected to freezing or freeze-drying. These methods have previously been developed for bedside monitoring of patients receiving c7E3 (Reopro(R)).

MATERIALS AND METHODS

Platelet-induced clot retraction (PICR) and clot strength were measured with the Hemodyne and Thromboelastograph, respectively. Paired Study: Fresh platelet concentrates (n = 3) were obtained from leukapheresis donors and divided into two equal units; one unit was tested within 4 h of collection and the other stored for 5 days at 22 degrees C in a platelet incubator and tested. Unpaired Study: Fresh platelet concentrates (n = 15) were obtained from leukapheresis donors and tested within 4 h of collection and compared to outdated platelets (n = 30; random or single donor) that had been stored for 5 days at 22 degrees C in a platelet incubator. Alternative Preservation Methods: Lyophilized platelets, platelets chilled to 4 degrees C, platelets frozen at -70 degrees C in 5% dimethyl sulfoxide (DMSO) or in the absence of a cryoprotectant.

RESULTS

Paired Study: Stored platelets demonstrated an increase in PICR; the difference was not significant (p = 0.55). There was no difference in clot strength between fresh and outdated platelets (p = 0.90). Unpaired Study: When compared to fresh platelets, stored platelets demonstrated a 2-fold higher PICR (p = 0.0011). On the other hand, there was no difference in the time to onset of PICR (p = 0.08) and there was no difference in clot strength between fresh and outdated platelets (p = 0.14). Alternate Preservation Methods: In contrast, PICR and clot strength were reduced in platelets frozen at -70 degrees C in 5% DMSO and absent in lyophilized platelets, in platelets frozen at -70 degrees C in the absence of cryoprotectants or stored at 4 degrees C.

CONCLUSION

The data indicate that the ability of platelets to induce clot retraction and to enhance clot strength is not altered by storage, despite functional abnormalities in aggregation and agglutination. These data suggest that quantitative measurements of PICR and clot strength may be simple, useful tools for assessing the function of stored platelet concentrates, platelets that have undergone freezing or exposure to alternative buffers and for evaluating platelet functions relevant to PICR.

Improved branching ratio measurement for the decay K(0)(L) --> &mgr;(+)&mgr;(-)

We report results from Experiment 871, performed at the BNL AGS, of a measurement of the branching ratio K(0)(L)-->&mgr;(+)&mgr;(-) with respect to the CP-violating mode K(0)(L)-->pi(+)pi(-). This experiment detected over 6200 candidate &mgr;(+)&mgr;(-) events, a factor of 6 more than that seen in all previous measurements combined. The resulting branching ratio gamma(K(0)(L)-->&mgr;(+)&mgr;(-))/gamma(K(0)(L)-->pi(+)pi(-)) = (3. 474+/-0.057)x10(-6) leads to a branching fraction B(K(0)(L)-->&mgr;(+)&mgr;(-)) = (7.18+/-0.17)x10(-9), which is consistent with the current world average, and reduces the uncertainty in this decay mode by a factor of 3.

Phase variation of HpuAB and HmbR, two distinct haemoglobin receptors of Neisseria meningitidis DNM2

We have previously described HpuAB, a two-component receptor that mediates binding to haemoglobin (Hb), haemoglobin-haptoglobin (Hb-Hp) and apo-haptoglobin (Hp). In this communication, we constructed non-polar mutations in the hpuA and hpuB loci to examine the individual roles of HpuA and HpuB. Our results indicate that both HpuA and HpuB are required for the acquisition of Fe from Hb and Hb-Hp. We isolated Hb utilization-positive (Hb+) variants of our Hb utilization-negative (Hb-) hpu mutants at a frequency of 10(-3) and demonstrated that the Hb+ phenotype resulted from the expression of a second Hb receptor, HmbR. Expression of HmbR in DNM2 was found to be controlled by translational frameshifting involving a polyguanine (G) tract located within the hmbR locus. The hpuA locus also contains a poly(G) tract, which suggested that meningococci could phase vary each Hb receptor independently by slip-strand mispairing in the poly(G) tracts found in hpuA and hmbR. Thus, we isolated a naturally occurring Hb- variant of DNM2, designated DNM2 Hb-, which did not express either HpuAB or HmbR. Hb+ variants of DNM2Hb- were selected and examined for HpuAB and HmbR expression. In each instance, acquisition of HpuAB or HmbR expression was correlated with phase variation in the poly(G) tract of each Hb receptor.

Transport of intact porphyrin by HpuAB, the hemoglobin-haptoglobin utilization system of Neisseria meningitidis

The meningococcal hemA gene was cloned and used to construct a porphyrin biosynthesis mutant. An analysis of the hemA mutant indicated that meningococci can transport intact porphyrin from heme (Hm), hemoglobin (Hb), and Hb-haptoglobin (Hp). By constructing a HemA- HpuAB- double mutant, we demonstrated that HpuAB is required for the transport of porphyrin from Hb and Hb-Hp.

Increased living donor volunteer rates with a formal recipient family education program

We have generally encouraged living donation among our kidney recipients. However, an examination of our clinical practice revealed inconsistencies in the depth and content of information transmitted to kidney recipient families regarding living donation. We therefore initiated a structured education program, including an educational video, to ensure that all recipient families would receive a similar exposure to a standard block of information. After the program had been functioning for over a year, we compared the living donor (LD) volunteer rates between the 3-year period before (BEFORE) and the 18 months after (AFTER) initiation of the formal education program. There were 1,363 patients registered on our kidney transplantation waiting list during the 54-month study period (757 white [56%] and 580 black [43%]). We found that 33.4% of the kidney transplant candidates in the period BEFORE the LD education program had at least one potential LD tissue typed, compared with 39.4% in the period AFTER starting the program (P = 0.03). The increase in the proportion of patients with potential donors was greatest among the black (P < 0.05) and elderly (P < 0.01) registrants, which were the groups with the lowest volunteer rates before the program began. Among the registrants with at least one potential donor, the percentage of registrants who ultimately received an LD transplant was highly correlated with the number of donors (R = 0.98). The rate of LD kidney transplantation was significantly higher (P = 0.02) for the patients referred in the period AFTER initiation of the LD education program compared with the period BEFORE the program. The 1- and 3-year graft survival rates for the 170 LD transplants performed in these patients were 96.9% and 93.2%, respectively. These were significantly better than the corresponding 83.9% and 71.4% rates for the 341 kidney transplants from cadaver donors in these registrants (P < 0.001). Black recipients of LD transplants had graft survival rates comparable to whites; the 3-year graft survival rate for LD transplants was 93.9% in whites and 90.6% in blacks (P = NS). We conclude that living kidney donor volunteer rates can be improved by a formal family education program, especially for subgroups of patients with low volunteer rates. A substantial benefit is derived by black patients, who generally experience low graft survival rates with cadaver-donor kidneys. A local formal LD education program is a useful adjunct to national organ donation campaigns.

Structure of the promoter and genomic organization of the human beta'-adaptin gene (BAM22) from chromosome 22q12

Adaptins are major structural components of heterotetrameric protein complexes called adaptors, which are essential in intracellular receptor transport via clathrin-coated vesicles. beta-adaptins constitute one of three known classes (alpha, beta, gamma) of adaptins, including beta and beta' subtypes. We previously cloned the human beta'-adaptin gene (BAM22) (GDB symbol, ADTB1) from chromosome 22q12 and proposed its involvement in the development of meningiomas. Here we describe the genomic organization of this gene, which consists of 22 exons spanning over approximately 100 kb. We also report results from point mutation screening of 7 randomly chosen exons analyzed in 110 sporadic meningiomas. As part of the genomic characterization of the BAM22 locus, we sequenced 40 kb covering exons 1-4 and 12 kb upstream from the start of gene transcription. Analysis of the sequence suggests that the BAM22 gene has a CG-rich promoter.

Rodenticide-induced coagulopathy in a young child. A case of Munchausen syndrome by proxy

PURPOSE

To present the diagnosis and management of superwarfarin ingestion, a cause of serious and prolonged coagulopathy.

METHODS

Specific identification of the anticoagulant was made by high-pressure liquid chromatography.

RESULTS

A 24 month-old child developed bruises and a prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT) after receiving multiple doses of brodifacoum, a superwarfarin rodenticide. The coagulopathy was treated successfully with large doses of parenteral and oral vitamin K1; fresh frozen plasma was administered as a precautionary measure on two occasions. After the first 10 days of the child's hospitalization, the mother was identified as the source of brodifacoum, exemplifying the behavior described as Munchausen syndrome by proxy. Oral vitamin K1 was initiated and continued in an outpatient setting with tapering doses over nine months, using the PT as a guide for therapy.

CONCLUSIONS

This report emphasizes the necessity of recognizing rodenticide poisoning and investigating its source. Frequent monitoring of the PT is essential to prevent hemorrhagic complications due to repeat exposure, inadequate vitamin K1 therapy, or noncompliance.

G-6-PD Walter Reed: possible insight into "structural" NADP in G-6-PD

A new G-6-PD variant, G-6-PD Walter Reed, causing hereditary nonspherocytic hemolytic anemia is characterized. This variant is unusual in that its stability requires the presence of high concentrations of NADP, while its Km for NADP is normal. This finding is consistent with the suggestion that G-6-PD has two separate binding sites, a high affinity "structural" site and a lower affinity catalytic site. The mutation in G-6-PD Walter Reed, like that of the previously described variant, G-6-PD Torrance, may be due to a mutation of the "structural" site for NADP.

Psychological issues in the care of critically-ill respirator patients: differential perceptions of patients, relatives, and staff

Using questionnaire rating scales, 21 ventilator patients, 17 family members, and 31 members of the medical staff who cared for the patients indicated their perceptions of the ventilator care situation with particular attention given to factors that may be sources of psychological stress for respirator patients. As expected, patients who reported problems in communicating with staff and family due to inability to talk and, in some cases, to write while on the respirator also reported strong feelings or negative emotions, e.g., anger, frustration, fear. The perceptions of staff, patients, and family differed significantly concerning problematic aspects of the respirator care situation. These results have implications for future research dealing with psychological issues of patients in critical care settings