180. Impact of a two-step diagnostic bundle on hospital-onset Clostridioides difficile infection rates and treatment across a large health system

Background

Distinguishing true Clostridioides difficile Infection (CDI) from colonization is a challenge, with nearly 20% of hospitalized adults being carriers of C. difficile. Polymerase chain reaction (PCR) testing alone is not able to distinguish colonization from infection, leading to over-diagnosis and unnecessary treatment. Despite interventions including pre-approval by antimicrobial stewardship programs (ASP), reportable hospital-onset CDI (HO-CDI) rates across our health system remained high. In 2021, we implemented a C. difficile PCR with reflex toxin enzyme immunoassay (EIA) testing strategy to improve diagnostic accuracy and treatment outcomes. The purpose of this study was to evaluate the impact of this two-step testing algorithm bundled with education, ASP support and order set changes on HO-CDI rates and C. difficile treatment across our health system.

Methods

PCR with EIA testing algorithm was implemented between May and August 2021 across seven hospitals within the Northwestern Medicine Health System. Multifaceted education was delivered to leadership and clinicians in person and electronically to. ASP performed daily diagnostic prospective audit and management support. Clinical decision support (CDS) was incorporated into order sets to promote diagnostic stewardship (Table 1, Figure 1). Standardization of analyst-developed tracking reports allowed for longitudinal monitoring across the system and at each facility, including unit- and patient-level data. Figure 1

Antibiotic Stewardship Attitudes and Beliefs Among Frontline Staff Nurses: Impact of Virtual Education

Background: Nurses are vital healthcare team members and are often underutilised in antimicrobial stewardship (AS) activities. Several nursing responsibilities, such as taking allergy history and obtaining cultures, already overlap with AS activities. Nurses can play a crucial role in promoting AS in resource-limited settings. This study was conducted to assess frontline staff nurses’ baseline attitudes and beliefs towards AS, and see if a virtual education campaign consisting of newsletters and tip sheets would affect those attitudes and beliefs. Methods: An online survey (pre-survey) was conducted of all in-patient nurses employed in the authors’ hospital on their attitudes and beliefs regarding AS. The survey consisted of 24 questions divided into three domains: demographic and practice information, nursing roles, and beliefs and attitudes towards AS programmes (ASP). After obtaining the results of the pre-survey, the authors started distributing monthly newsletters on various AS topics via email and posting them on a resource page. Topics included how to obtain an accurate allergy history, how to use microbiology results to help guide decisions, and stop therapy in cases of colonisation. The authors also distributed the same survey as a follow-up 6-month survey (post-survey) in March 2021 to gauge the impact of their virtual education efforts. Results: In total, 109 nurses working in the adult in-patient setting of the authors’ institution completed the pre-survey in September 2020, and 64 nurses completed the post-survey in March 2021. Overall, most nurses had a positive attitude towards AS tasks, and over 90% of those who responded in the pre-survey and post-survey agreed with the statement that nurses are antibiotic stewards, thought it was important or very important to obtain appropriate cultures, and understood the relationship between Clostridioides difficile and antibiotics. Most pre-survey respondents listed knowledge gaps in microbiology (47 out of 64 [86%]) and antibiotics (53 out of 64 [84%]) as well as scope of practice concerns (48 out of 64 [75%]) as barriers to nurse participation. The virtual education helped raise the familiarity with the ASP and more nurses in the post-survey said they were familiar with the stewardship programme compared with the pre-survey (48.4% versus 23.2%; p=0.001). Conclusions: This study showed that most nurses consider themselves antibiotic stewards and want to participate in AS activities; however, barriers to nursing involvement, such as lack of knowledge, scope of practice concerns, and time constraints, persist. Virtual education may be an option to increase nursing awareness and participation on ASPs in resource-limited settings.

Relationship Between the Skin Surface Temperature Changes During Sprint Interval Testing Protocol and the Aerobic Capacity in Well-Trained Cyclists

The study investigated whether changes in body surface temperature in a sprint interval testing protocol (SITP) correlated with aerobic capacity in cyclists. The study involved 21 well-trained cyclists. Maximal aerobic power and maximal oxygen uptake relative to lean body mass (LBM-P(max) and LBM-VO(2max), respectively) were determined by incremental exercise testing on a cycle ergometer. SITP was administered 48 hours later and involved four 30-s maximal sprints interspersed with 90-s active recovery. Body surface temperature was recorded at the temple and arm and the delta difference between baseline temperature and temperature measured immediately after the first sprint (DeltaTt(1) and DeltaTa(1), respectively) and 80 seconds after the fourth sprint (DeltaTt(4) and DeltaTa(4)), respectively) was calculated. Significant correlations were found between DeltaTt4 and LBM-Pmax and LBM-VO(2max) (r=0.63 and r=0.75, respectively) with no significant change in DeltaTa(1) or DeltaTa(4). Body surface temperature, measured at the temple region, can be used to indirectly assess aerobic capacity during maximal sprint exercise.

Time of VO(2)max plateau and post-exercise oxygen consumption during incremental exercise testing in young mountain bike and road cyclists

The purpose of this study was to compare markers of glycolytic metabolism in response to the Wingate test and the incremental test in road and mountain bike cyclists, who not different performance level and aerobic capacity. All cyclists executed the Wingate test and incremental test on a cycle ergometer. Maximal power and average power were determined during the Wingate test. During the incremental test the load was increased by 50 W every 3 min, until volitional exhaustion and maximal aerobic power (APmax), maximal oxygen uptake (VO2max), and time of VO(2)max plateau (Tplateau) were determined. Post-exercise measures of oxygen uptake (VO(2)post), carbon dioxide excretion, (VCO(2)post), and the ratio between VCO(2)/VO(2) (RERpost) were collected for 3 min immediately after incremental test completion. Arterialized capillary blood was drawn to measure lactate (La-) and hydrogen (H+) ion concentrations in 3 min after each test. The data demonstrated significant differences between mountain bike and road cyclists for Tplateau, VO(2)post, VCO(2)post, La- which was higher-, and RERpost which was lower-, in mountain bike cyclists compare with road cyclists. No differences were observed between mountain bike and road cyclists for APmax, VO(2)max, H(+) and parameters measured in the Wingate test. Increased time of VO2max plateau concomitant to larger post-exercise La- and VO(2) values suggests greater anaerobic contribution during incremental testing efforts by mountain bike cyclists compared with road cyclists.

Effects of Left Ventricular Assist Device Support on End-Organ Function in Patients With Heart Failure: Comparison of Pulsatile- and Continuous-Flow Support in a Single-Center Experience

BACKGROUND

Limited data exist about the effects of continuous-flow versus pulsatile-flow left ventricular assist devices (LVADs) on end-organ function. We hypothesized that a pulsatile Polvad MEV (PM) would result in outcomes similar to those of similarly ill patients implanted with a continuous-flow LVAD (Heartware [HW] or Heartmate II [HMII]). We aimed to compare renal, hepatic, and hematologic functions in the 1st 30 days of support.

METHODS

We retrospectively reviewed patients with 24 PM (21 M, 3 F; group P) and 15 HW and 5 HMII (20 M, 0 F); group C LVAD implantations from April 2007 to February 2014. Creatinine, bilirubin, aspartate (AST) and alanine (ALT) transaminases, hematocrit, platelet count, international normalized ratio (INR), and activated partial thromboplastin time (APTT) parameters were analyzed before implantation and during 30 days of support. Demographic parameters were similar.

RESULTS

No significant differences were found between the groups regarding baseline renal, hepatic, or hematologic function. Baseline INR and APTT were significantly higher in group P. Levels of creatinine were similar between groups. They increased from baseline to postoperative day (POD) 1 and then decreased. Bilirubin levels were insignificantly higher in group P. Transaminases were significantly higher in group P (AST in PODs 3-6, ALT in PODs 3-7). INR values were significantly higher at baseline and in POD 0. APTT values were insignificantly higher in group P.

CONCLUSIONS

The use of LVAD improved renal and hepatic function in our series. Patients in group P had more decreased hepatic function and presented slower regeneration.

Comparison of Mechanical Circulatory Support by the Use of Pulsatile Left Ventricular Assist Devices Polvad MEV and Continuous Flow Heart Ware and Heart Mate II in a Single-Center Experience

BACKGROUND

Mechanical circulatory support is increasingly used in patients with heart failure as a bridge to transplant or recovery. Results of use the Polish POLVAD MEV pulsatile circulatory support system and its comparison with novel devices never was done. We compared the course of patients with left ventricular circulatory support (left ventricular assist device [LVAD]) supported by POLVAD MEV or continuous flow devices Heart Mate II (HM II) and Heart Ware (HW) in single-center cohort.

METHODS

We retrospectively reviewed 44 patients who underwent Polvad Mev (group P; n = 24 [21M/3F]) or HW or HM II (group C; n = 20 [20M/0F]) implantation between April 2007 and February 2014. Patients were in INTERMACS 1 (6 in group P and 1 in group C) or 2. Preimplant demographics, and perioperative and postoperative clinical outcomes were reviewed between groups. We analyzed baseline signs of heart failure, comorbidities, complications, and the 30- and 90-day results.

RESULTS

Among the groups, age, gender, weight, and cause of heart failure were comparable. Patients in group C suffered more frequently from hypercholesterolemia preoperatively. Patients in group P had more pulmonary complications (7 vs 0) after LVAD implantation and stay longer on intensive care unit than patients in group C (17.61 ± 16.96 vs 9.56 ± 9.42; P = .047). After exclusion, INTERMACS 1 patients it was not significant (14.8 ± 10.8 vs 9.8 ± 9.6 days; P = .065), the 30- and 90-day mortality was comparable.

CONCLUSIONS

Implantation of pulsatile POLVAD MEV and continuous flow devices as LVAD support provides comparable results. A greater number of complications in group P can cause increased mortality over a longer observation period.

The relationship between concentrations of vitamin D-binding protein (DBP) in serum and colostrum of mares and in serum of their foals in the neonatal period

Vitamin D-binding protein (DBP) participates in the actin scavenger system, it is a carrier of vitamin D and its derivatives, it manifests the capacity to bind mainly monounsaturated and saturated fatty acids, it binds to the surface of several cells and enhances chemotactic activity of C5a of the complement. The present study was aimed at answering the question whether serum DBP level in mares is related to levels of this protein in colostrum and in serum of its progeny. For this purpose, sera from 77 mares, colostra from 72 mares and sera from 69 Thoroughbred foals were collected. Mother's age, number of deliveries experienced in the past, month of delivery, feeding of foals with colostra were recorded. Blood of the foals was sampled from the umbilical vein during delivery (0h) and 36-48 h after delivery from the external jugular vein, colostra of the mares were obtained after delivery and blood of the mares was sampled 36-48 h after delivery. Concentration of DBP was estimated by a self-designed ELISA. In the present study, DBP concentrations in newborn's serum were found independent of their concentrations in mother's serum, her age and number of parities experienced in the past. Colostrum DBP level was found to be lower than that in the mare's serum and was not correlated to the concentration of this protein in mare's serum. There was no effect of colostrum feeding on DBP level in the foal serum. These results indicate that serum DBP concentration in newborn foals depends on factors which act directly on the foal. Because of the lack of correlation between plasma and colostrum concentrations of DBP, it can be assumed that DBP is synthesised in the mammary gland and/or specific transport mechanisms exist in the mammary gland.

Soluble selectin profiles associated with severe trauma

Severe trauma acts as a trigger for the complex cascade of postinjury events leading to the release of different mediators and the development of generalized inflammation. Selectins are a family of adhesion proteins that are responsible for the adherence of polymorphonuclear neutrophils to the endothelium. This interaction plays an important role in the development of severe complications after multiple trauma. The aim of the present study is to follow the sequential alterations in circulating selectin levels after severe injury and to evaluate the clinical significance of these mediators in monitoring prognosis and outcome. Thirty four severely traumatized patients were entered into the study. Serum sE-selectin, plasma sP-selectin and sL-selectin concentrations were measured and an APACHE II score was calculated on admission to the intensive care unit and during the subsequent 5 days. The patients were divided into survivors and nonsurvivors. Initial soluble P- and E-selectin concentrations were significantly elevated in all trauma patients. The highest values of these adhesion molecules were measured in all the observed days in patients with poor prognosis and outcome. In survivors we found a systematic decrease in the sP-selectin concentrations. On admission, the sL-selectin concentrations in all trauma patients were decreased. There were stable, very low values in nonsurvivors and a slow increase in circulating L-selectin in patients who survived. The pattern of soluble selectins in patients with severe trauma is characterized by increased levels of P- and E-selectin and a decreased concentration of L-selectin. These findings suggest a widespread microvascular endothelial activation on injury in the early posttraumatic period, which may be associated with increased neutrophil-endothelial adhesion, neutrophil extravasation and migration. We suppose that these parameters of endothelial cell activation/injury may be useful as another early prognostic factor in severe trauma.

Fine-needle aspiration cytology of hemangiopericytoma: report of two cases

The fine-needle aspiration biopsy (FNAB) findings in two cases of hemangiopericytoma (HP), arising in the parotid gland and on the inner chest wall, respectively, are reported. Smear preparations in each case showed cytologic features of an undifferentiated spindle-cell neoplasm, whereas a core needle biopsy specimen of the chest wall mass showed a spindle-cell tumor with a "staghorn-like" arrangement of endothelium-lined vascular channels. Immunostains performed on this core biopsy, and on the surgical resection specimens in both cases, showed positive staining of tumor cells for vimentin and CD34, with negative staining for a variety of smooth muscle, epithelial, neural, and neuroendocrine markers. Electron microscopy performed in one case further supported the diagnosis of HP. With adequate sampling and appropriate use of ancillary studies, a diagnosis of HP can be reliably suggested on the basis of FNAB and core biopsy of a soft-tissue mass.

Steam sterilizable probes for dissolved oxygen measurement. Reprinted from Biotechnology and Bioengineering, Vol. VI, Issue 4, Pages 457-468 (1964)

Steam-sterilizable membrane probes for monitoring the dissolved oxygen level in fermentors, or the oxygen content of gas streams, are described. The probes have a silver cathode, a lead anode, and an acetate buffer as an electrolyte. The membrane is Teflon. The current output of the probes in the absence of oxygen is negligible.

Fulminant parvovirus infection following erythropoietin treatment in a patient with acquired immunodeficiency syndrome

We report the case of a 41-year-old black man with acquired immunodeficiency syndrome who developed a severe chronic anemia due to parvovirus infection. Bone marrow biopsy revealed erythroid aplasia. The infectious nature of the anemia was not recognized, and the patient was treated with erythropoietin. The patient's reticulocyte response was inadequate, however, and he remained anemic. A second bone marrow biopsy showed erythroid hyperplasia and prominent intranuclear parvovirus inclusions within erythroid progenitors. Erythropoietin was discontinued and was followed by a course of intravenous immunoglobulin, which resulted in rapid correction of anemia. To our knowledge, this is the first reported case of fulminant human parvovirus infection exacerbated by erythropoietin administration and documented by sequential bone marrow histologic examination. This case illustrates the critical importance of considering parvovirus in the etiology of chronic anemia with erythroid aplasia in immunocompromised patients.

MULTICLUSTAL: a systematic method for surveying Clustal W alignment parameters

MULTICLUSTAL is a Perl script designed to automate the process of alignment parameter choice for Clustal W with the goal of generating high quality multiple sequence alignments.

Cloning and characterization of a new subtype of thyrotropin-releasing hormone receptors

A new subfamily member of thyrotropin releasing hormone (TRH) receptor gene, TRHR2, was isolated from rat brain cDNAs. The deduced amino acid sequence of TRHR2 is 51 % identical to that of rat TRH receptor gene which was reported previously. Northern blot analysis with TRHR2 probe revealed brain-specific expression of a 9.5 kb mRNA. In a binding experiment using the TRHR2-expressing COS cells, specific binding of TRH to TRHR2 was observed with Kd value of 9 nM which was equivalent to the Kd value (= 13 nM) of TRH binding to the TRH receptor previously reported. The active metabolite of TRH, histidyl-proline diketopiperazine, or cyclo(His-Pro), showed no specific binding activity. These results suggest that TRHR2 is a novel subtype of TRH receptor.

Purification and characterization of a kinase-associated, myofibrillar smooth muscle myosin light chain phosphatase possessing a calmodulin-targeting subunit

A myofibrillar form of smooth muscle myosin light chain phosphatase (MLCPase) was purified from turkey gizzard myofibrils, and it was found to be closely associated with the myosin light chain kinase (MLCKase). For this reason we have named this phosphatase the kinase- and myosin-associated protein phosphatase (KAMPPase). Subunits of the KAMPPase could be identified during the first ion exchange chromatography step. After further purification on calmodulin (CaM) and on thiophosphorylated regulatory myosin light chain affinity columns we obtained either a homogenous preparation of a 37-kDa catalytic (PC) subunit or a mixture of the PC subunit and variable amounts of a 67-kDa targeting (PT) subunit. The PT subunit bound the PC subunit to CaM affinity columns in a Ca2+-independent manner; thus, elution of the subunits required only high salt concentration. Specificity of interaction between these subunits was shown by the following observations: 1) activity of isolated PC subunit, but not of the PTC holoenzyme, was stimulated 10-20-fold after preincubation with 5-50 microM of CoCl2; 2) the pH activity profile of the PC subunit was modified by the PT subunit (the specific activity of the PTC holoenzyme was higher at neutral pH and lower at alkaline pH); and 3) affinity of the holoenzyme for unphosphorylated myosin was 3-fold higher, and for phosphorylated myosin it was 2-fold lower, in comparison with that of the purified PC subunit. KAMPPase was inhibited by okadaic acid (Ki = 250 nM), microcystin-LR (50 nM) and calyculin A (1.5 microM) but not by arachidonic acid or the heat-stable inhibitor (I-2), which suggested that this is a type PP1 or PP2A protein phosphatase.

Purification and characterization of a smooth muscle myosin light chain kinase-phosphatase complex

We show that a myofibrillar form of smooth muscle myosin light chain phosphatase (MLCPase) forms a multienzyme complex with myosin light chain kinase (MLCKase). The stability of the complex was indicated by the copurification of MLCKase and MLCPase activities through multiple steps that included myofibril preparation, gel filtration chromatography, cation (SP-Sepharose BB) and anion (Q-Sepharose FF) exchange chromatography, and affinity purification on calmodulin and on thiophosphorylated regulatory light chain columns. In addition, the purified complex eluted as a single peak from a final gel filtration column in the presence of calmodulin (CaM). Because a similar MLCPase is present in varying amounts in standard preparations of both MLCKase and myosin filaments, we have named it a kinase- and myosin-associated protein phosphatase (KAMPPase). The KAMPPase multienzyme complex was composed of a 37-kDa catalytic (PC) subunit, a 67-kDa targeting (PT) subunit, and MLCKase with or without CaM. The approximate molar ratio of the PC and PT subunits was 1:2 with a variable and usually higher molar content of MLCKase. The targeting role of the PT subunit was directly demonstrated in binding experiments in which the PT subunit bound to both the kinase and to CaM. Its binding to CaM was, however, Ca2+-independent. MLCKase and the PT subunit potentiated activity of the PC subunit when intact myosin was used as the substrate. These data indicated that there is a Ca2+-independent interaction among the MLCPase, MLCKase, and CaM that are involved in the regulation of phosphatase activity.

The GABAB receptor antagonist CGP 36,742 and the nootropic oxiracetam facilitate the formation of long-term memory

The memory-enhancing effects of a single treatment with the GABAB antagonist CGP 36,742 (10 mg/kg) or the nootropic agent oxiracetam (100 mg/kg) given immediately after a learning experience ('post-trial') remain detectable for at least 4 months thereafter. This indicates that in all probability these substances facilitate the formation of the long-term memory trace.

The memory-facilitating effects of the competitive NMDA-receptor antagonist CGP 37849 are steroid-sensitive, whereas its memory-impairing effects are not

The retention performance of mice in a passive-avoidance task was facilitated by low doses (0.3 mg/kg) of the competitive NMDA-receptor blocker CGP 37849, but impaired by high doses (30 mg/kg). The facilitatory effect was selectively suppressed by elevation of the plasma levels of aldosterone or corticosterone, or by blockade of steroid biosynthesis or the mineralocorticoid receptors. The impairment of memory, on the other hand, was not steroid sensitive. Accordingly, the data are in line with the hypothesis that drug induced memory facilitation is dependent on steroid sensitive processes.

Experimental Studies and Theoretical Predictions for the H + D2 rarr > HD + D Reaction

The H + H(2) exchange reaction constitutes an excellent benchmark with which to test dynamical theories against experiments. The H + D(2) (vibrational quantum number v = 0, rotational quantum number j = 0) reaction has been studied in crossed molecular beams at a collision energy of 1.28 electron volts, with the use of the technique of Rydberg atom time-of-flight spectroscopy. The experimental resolution achieved permits the determination of fully rovibrational state-resolved differential cross sections. The high-resolution data allow a detailed assessment of the applicability and quality of quasi-classical trajectory (QCT) and quantum mechanical (QM) calculations. The experimental results are in excellent agreement with the QM results and in slightly worse agreement with the QCT results. This theoretical reproduction of the experimental data was achieved without explicit consideration of geometric phase effects.

Delayed emergence of effects of memory-enhancing drugs: implications for the dynamics of long-term memory

Many theories of memory postulate that processing of information outlasts the learning situation and involves several different physiological substrates. If such physiologically distinct mechanisms or stages of memory do in fact exist, they should be differentially affected by particular experimental manipulations. Accordingly, a selective improvement of the processes underlying short-term memory should be detectable only while the information is encoded in the short-term mode, and a selective influence on long-term memory should be detectable only from the moment when memory is based on the long-term trace. Our comparative study of the time course of the effects of the cholinergic agonist arecoline, the gamma-aminobutyric acid type B receptor antagonist CGP 36742, the angiotensin-converting enzyme inhibitor captopril, and the nootropic oxiracetam, four substances with completely different primary sites of action, show that the memory-enhancing effects consistently come into evidence no sooner than 16-24 h after the learning trial. On the one hand, this finding suggests that all these substances act by way of the same type of mechanism; on the other hand, it demonstrates that the substrate modulated by the compounds forms the basis of memory only after 16-24 h. From the observation that animals also show clear signs of retention during the first 16 h--i.e., before the effects of the substances are measurable--it can be inferred that retention during this time is mediated by other mechanisms that are not influenced by any of the substances.

Inner-city pharmacies: can they meet the OBRA '90 mandates?

Visits were made to 21 pharmacies in two poor Chicago neighborhoods as one component of the University of Illinois at Chicago's commitment to help improve health care delivery, ensure that pharmacy services are not overlooked in local health reform efforts, and understand the implications of the Omnibus Budget Reconciliation Act of 1990 (OBRA '90). Pharmacists report that Medicaid reimbursement policies result in: (1) prescribing patterns that have no consistent therapeutic or economic rationale; (2) dispensing of expensive drugs, some of which are then sold on the street or to other pharmacies; and (3) dispensing of unnecessary and often expensive legend drugs when other legend drugs and generics or over-the-counter products would perform just as well. On the positive side, 76% of the pharmacies possess computerized patient-profile systems, and 72% maintain background information on their prescribers. These results suggest that OBRA '90's mandates should contribute toward improving the Medicaid program, but that implementation is likely to be difficult and uneven.

Urethral stricture repair: results in 179 patients

From 1977 till April 1990 169 operative reconstructions of urethral strictures were carried out in this clinic. 49 patients with a short stricture (less than 2 cm) underwent excision and end to end anastomosis. In 18 patients with a long stricture (2-6 cm) one stage urethroplasty with a transverse distal penile or preputial island of skin flap was used. 102 patients with extensive or otherwise problematic strictures were subjected to two-stage mesh skin graft urethroplasty. In 10 patients with a short stricture we have recently implanted a new urethral stent in the strictured area after visual urethrotomy. During a long-time follow-up a good anatomical and functional result was achieved in all but 2 patients who underwent an excision and end to end anastomosis. In the island flap urethroplasty group a restricture occurred in one patient, and mesh graft urethroplasty was successful in all but 3 patients. In the urethral stent patients the primary results are excellent.

CGS 5649 B, a new compound, reverses age-related cognitive dysfunctions in rats

CGS 5649 B improves the learning performance of aged rats in a one-way active-avoidance situation. If, under reversed conditions, treated aged rats are also tested for passive avoidance, they show "place learning," which our findings have demonstrated to be typical of young rats. The effects of the substance are not confined to these experimental models nor are they species specific: it also facilitates passive avoidance in mice and social learning in rats. The compound is effective if administered before or immediately after the learning trial.

Pretreatment with aldosterone or corticosterone blocks the memory-enhancing effects of nimodipine, captopril, CGP 37,849, and strychnine in mice

Oral pretreatment with aldosterone or corticosterone blocked the memory-enhancing effects of the calcium antagonist nimodipine, the ACE inhibitor captopril, the NMDA blocker CGP 37,849, and the glycine antagonist strychnine in a passive-avoidance test in mice. The memory-disturbing effects of phenobarbitone, diazepam, CGP 37,849 and scopolamine were not influenced by the hormonal pretreatment. These findings could indicate the involvement of a steroid-sensitive mechanism in drug-induced improvement of memory. In the light of clinical observations showing elevated cortisol levels in Alzheimer patients, the results might also explain why only a limited number of these patients respond to therapy with memory enhancers.

How long does 'memory consolidation' take? New compounds can improve retention performance, even if administered up to 24 hours after the learning experience

The 'nootropics' are a new class of psychoactive substances that improve learning and memory. Their almost exclusive effect on memory may indicate that they act on processes specifically involved in information storage. When administered after the learning trial, these substances improve subsequent retention performance in mice, even if an interval of 8 h has elapsed between learning and treatment. CGS 5649B, a highly active new substance, is effective even after an interval of 24 h. Although consonant with the 'consolidation' hypothesis, the results may challenge prevailing notions about the formation of memory traces.

Purification and some properties of Pseudomonas fluorescens lipase

Lipase (triacylglycerol lipase, EC 3.1.1.3) has been purified from Pseudomonas fluorescens wild strain by chromatography on DEAE-cellulose and octyl-Sepharose CL-4B. The yield was 21% and the specific activity of the purified enzyme 4780 U/mg protein. It showed a Mr of about 45 x 10(4) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme is active over a wide pH range and at 50-55 degrees C.

The Epstein-Barr virus BZLF1 gene product activates the human immunodeficiency virus type 1 5' long terminal repeat

The Epstein-Barr virus immediate-early gene product BZLF1 transactivates the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR). The BZLF1 gene product caused an 18-fold increase in beta-galactosidase activity from an HIV-1 LTR lacZ expression vector, whereas the HIV-1 transactivator tat caused a 44-fold increase in beta-galactosidase activity. When cells were transfected with both BZLF1 (pEBV-Z) and tat (pTAT3) expression vectors, as well as HIV-1 LTR lacZ plasmid (pLRON), a 214-fold increase in beta-galactosidase activity was observed. This result suggests a synergistic effect of BZLF1 and tat on HIV-1 LTR-directed lacZ gene expression. Analysis of quantitative BZLF1 and tat requirements for maximal HIV-1 LTR activation indicates that BZLF1 does not reduce the amount of tat required for maximal LTR activation, as would be expected if the BZLF1 synergistic effect was due to increased tat gene expression. Thus, coordinate effects of BZLF1 and tat on the HIV-1 LTR or its transcript are probably responsible for synergistic HIV-1 LTR activation.

Protein: creatinine and trypsin inhibitor: creatinine ratios in the urine of marathon runners

We measured changes in the protein: creatinine and trypsin inhibitor: creatinine ratios in the urine of six male marathon runners. Samples of urine were collected before the run, immediately after the run and in 6-h collections for 2 days. We found the greatest increase in the protein: creatinine ratio (2.6 times greater) in urine collected immediately after the run and the greatest increase in the trypsin inhibitor: creatinine ratio in urine samples collected 6-12 and 12-18 h after the run (2 and 3 times greater, respectively). This suggests the existence of different mechanisms for these two physiological processes. The later increase in the trypsin inhibitor: creatinine ratio was perhaps, due to a state of short-lived inflamation and shock after severe physical effort.

Involvement of a steroidal component in the mechanism of action of piracetam-like nootropics

Since adrenalectomy abolishes the memory-enhancing effects of piracetam and its derivatives, oxiracetam, aniracetam and pramiracetam, the question arises whether endogenous steroids play a role in their mechanism of action. We show that inhibition of steroid biosynthesis by aminoglutethimide and blockade of the aldosterone receptors by epoxymexrenone completely suppress the memory-improving effects of the nootropics. These results indicate that steroids, or, more precisely, activities mediated by the aldosterone receptors, might be involved in the mechanism of action of this class of nootropics. Blockade of aldosterone receptors, however, does not block the effects of cholinomimetics on memory, indicating the involvement of another mechanism of action.

The memory-enhancing effects of the piracetam-like nootropics are dependent on experimental parameters

The effects of the nootropic agent piracetam and its congeners oxiracetam, pramiracetam and aniracetam on the retention performance of mice in a passive-avoidance situation are dependent on the intensity of the foot-shock applied. This phenomenon is observed upon both pre-trial and post-trial drug administration.

Insights into Theiler's virus neurovirulence based on a genomic comparison of the neurovirulent GDVII and less virulent BeAn strains

Theiler's murine encephalomyelitis viruses (TMEV) are naturally occurring enteric pathogens of mice which can be divided into two subgroups based primarily on their neurovirulence after intracerebral inoculation: the highly virulent GDVII group and the less virulent TO strains. To begin to elucidate the molecular basis of neurovirulence of the two TMEV subgroups, we have cloned and sequenced the entire 8105 nucleotide RNA genome of the highly virulent GDVII virus and compared it to the less virulent BeAn 8386 virus (D. C. Pevear, M. Calenoff, E. Rozhon, and H. L. Lipton (1987) J. Virol. 61, 1507-1516). The viruses are 90.4% identical at the nucleotide level. The highest level of nucleotide identity is in the 5' and 3' noncoding regions of the RNAs (95.5 and 99.2%, respectively): regions believed to be important for control of viral RNA synthesis, initiation of translation, encapsidation, and virion uncoating. The 2303 amino acid polyproteins of BeAn and GDVII viruses are 95.7% identical at the amino acid level (99 of 2303 residues differed). Thirty-nine of these amino acid differences occur in the three surface coat proteins, VP1 (20 differences), VP2 (10 differences), and VP3 (9 differences), while the remainder of the changes are distributed throughout the polyprotein. Although these levels of identity are too low to determine where neurovirulence maps based solely on nucleotide sequence analysis, having the complete sequence will facilitate construction of recombinant BeAn-GDVII viruses to be used for this purpose.

Effects of anxiety on storage and retrieval processes in short-term memory

The effects of anxiety on storage and retrieval processes in short-term memory were investigated. 8-word units of high and low encodability were tested under conditions of free and prompted recall using strong or weak cues. Results during both test periods showed superior recall under conditions of strong cueing, high encodability, and low anxiety. An interpretation localizing the effects of anxiety in trace formation or storage phases was favored over a retrieval interpretation.