Prognostic value of left ventricular ventricular dyssynchrony in left bundle branch block patients

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with left bundle branch block (LBBB) patterns on the electrocardiogram include a heterogeneous group of patients with different prognosis and some of them with or without left ventricular mechanical dyssynchrony (LVMD). LVMD obtained by gated technetium 99m single photon emission computed tomography (SPECT) imaging could be an early tool to detect myocardial damage, identifying a high risk group.

Purpose

The aim of this study was to assess the prognostic value of LVMD in LBBB patients.

Methods

Five hundred and eighty consecutive patients with LBBB were referred for gated SPECT from August 2011 to June 2019. Phase analysis parameters Standard deviation (SD) and histogram bandwidth (HB) were obtained in rest gated SPECT imaging. LVMD was defined as the upper limit of the highest normal for phase analysis results in our control patients mean values plus two standard deviations (SD ≥ 21° or HB ≥ 67°). Follow up was performed by telephone contact or medical history review. Hard endpoint was all-cause death. Event-free survival curves were obtained. Univariate and multivariate regression analysis were performed.

Results

LVMD was observed in 254 (44%) patients. Compared to non LVMD patients had: similar age (67.68 ± 11.01 vs. 67.2 ± 10.3 y; p NS), more male (75.2% vs 39.6%), more hypertension (75.2% vs. 66.8%), more diabetes (22.8% vs. 13%) and more smoking history (31.9% vs. 23.7%) all p <0.05. A total of 495 patients completed the follow up (mean 29.8 ± 25.8 months). Fourteen patients died (2.8%), 12 had LVMD. Fig 1 shows Kaplan-Meier curve of event-free survival in relation to LVMD. Variables associated with all-cause death in the univariate analysis were: Score Rest Summed ≥ 4 (p 0.02), LV ejection fraction ≤ 35% (p < 0.01), diabetes (p 0.03) and LVMD (p <0.01). The absence of LVMD was a predictor of the lower risk of all-cause death in the multivariate analysis (adjusted hazard ratio: 0.13, 95% confidence interval: 0.03- 0.56; p < 0.01).

Conclusion

In our population of patients with LBBB, the absence of LVMD assessed by gated SPECT imaging identifies patients with lower risk of hard adverse events.

0427 Bicuculine Increased the Cataplexy in the Male Taiep Rats: An Animal Model of Narcolepsy with an Inherent Tubulopathy

Introduction

Narcolepsy is a hypersomnolence that is characterized by sleep fragmentation, sleep paralysis, hypnagogic hallucinations and cataplexy that is characterized by atonia induced by strong emotions. The amygdala is the trigger for cataplexy through GABAergic mechanisms. Taiep is a myelin mutant with TUBB4A tubulopathy which showed spontaneous episodes of atonia or induced by manipulations from the tail or the thorax. EEG recordings during immobility episodes (IE′s) had a cerebral cortex desynchronized associated to theta rhythm in the hippocampus. The aim of this sturdy was to analyze the effects of bicuculine administration on IE′s and sleep-wake pattern on adult male taiep rats.

Methods

We used 6 taiep male rats at 9 months of age. The subjects (Ss) lived in individual acrylic cages with water and food pellets available ad libitum, under a 12:12 light-dark cycle (lights on at 0700), with controlled temperature and humidity recording room. All Ss were implanted to record EEG, EMG and EOG to characterize EI′s. We evaluated a basal 24 h EEG recording and then after bicuculine i.p. administration of 0.5, 1 y 1.5 mg/Kg every 48h. We measured the number, mean duration and latency to the first IE′s.

Results

The duration of IE′s increased 527% with 1 mg/Kg and reach 700% with 1.5 mg/Kg of bicuculine (P<0.01) with respect to saline-treated control group. Importantly, the frequency of IEs did not differ among the groups and did not affect the number of awake, slow wave or rapid eye movements sleep phases.

Conclusion

Bicuculine, a specific GABA antagonist, modify the duration of IES but not their frequency supporting a role of GABAergic mechanism on IE′s. It is relevant because sodium oxybate, an indirect GABA agonist, reduced cataplexy and improved sleep quality on narcoleptic patients.

Support

CONACYT grants 243333 and 243247 to CC and JRE, respectively and from VIEP-BUAP 2019 to CA in Neuroendocrinología BUAP-CA-288.

0428 Taiep Rats Had Normal Levels of Orexin Neurons in the Lateral Hypothalamus But Their Cataplexy Attacks are Sensible to Specific Orexin B Agonist

Introduction

Narcolepsy is characterized by sleep fragmentation, sleep paralysis, hypnagogic hallucinations and cataplexy. The cataplexy is a sudden loss of muscle tone triggered by emotions in humans, as well as in animal models. It is stablished that most of the patients had a significant decrease of orexin neurons in the lateral hypothalamus. Taiep rats had a mutation in tubulin TUBB4A and suffer immobility episodes (IE′s) that had a desynchronized activity in the cortex associated with theta rhythm in the hippocampus similar to narcolepsy patients. The aim of this study was to analyze the effects of central administration of an orexin B agonist and determination by immunohistochemistry of the number of orexin neurons on adult male taiep rats.

Methods

We used 14 male taiep rats of 9 months of age. The subjects (Ss) lived 3-4 in acrylic cages with water and food pellets ad libitum, under a 12:12 light-dark cycle (lights on at 0700), whit-controlled temperature and humidity in the recording room. All Ss were implanted to record EEG, EMG and EOG to characterize immobility episodes (IE′s) in a control 8 h recording and after i.c.v. administration of [Ala 11, D-Leu 15]-orexin B with 1, 3 and 10 nmol/1 μL. We measured the number, mean duration and latency to the first IE′s.

Results

The administration of [Ala 11, D-Leu 15]-orexin B significantly reduced the number of IE′s (P<0.01), from 4.28 ± 1.5 IE′s to just 0.25 ± 0.17 with 10 nmol/1 μL dose, but did not change the amount of awakening, slow wave or rapid eye movement sleep. Importantly, the number or orexins neurons were similar between taiep and Sprague-Dawley rats.

Conclusion

The myelin mutant taiep rats is a model of narcolepsy with cataplexy with normal number of orexin neurons in the lateral hypothalamus. Additionally, a specific orexin B agonist reduced IE′s without any effect the sleep pattern. This could be useful for the design of new treatments.

Support

CONACYT grants 243333 and 243247 to CC and JRE, respectively. Grants from VIEP-BUAP 2019 and CA in Neuroendocrinología BUAP-CA-288.

HIV-related tuberculosis: mortality risk in persons without vs. with culture-confirmed disease

BACKGROUND

Tuberculosis (TB) diagnosis in human immunodeficiency virus (HIV) positive persons is difficult, particularly in resource-limited settings. The relationship between TB culture status and mortality in HIV-positive persons treated for TB is unclear.

METHODS

We evaluated HIV-positive adults treated for TB at or after their first HIV clinic visit in Argentina, Brazil, Chile, Honduras, Mexico or Peru from 2000 to 2015. Anti-tuberculosis treatment included 2 months of isoniazid, rifampicin (RMP)/rifabutin (RBT), pyrazinamide ± ethambutol, followed by continuation phase treatment with isoniazid + RMP/RBT.

RESULTS

Of 759 TB-HIV patients, 238 (31%) were culture-negative, 228 (30%) had unknown culture status or did not undergo culture and 293 (39%) were culture-positive. The median CD4 at TB diagnosis was 96 (interquartile range 40-228); 636 (84%) received concurrent antiretroviral therapy (ART) and anti-tuberculosis treatment. There were 123 (16%) deaths: 90/466 (19%) with TB culture-negative, unknown or not performed vs. 33/293 (11%) who were TB culture-positive (P = 0.005). In Kaplan-Meier analysis, mortality in TB patients without culture-confirmed disease was higher (P = 0.002). In a Cox model adjusted for age, sex, CD4, ART timing, disease site and stratified by study site, mortality in persons without culture-confirmed TB was not significantly increased compared to those with culture-positive TB (hazard ratio 1.39, 95%CI 0.89-2.16, P = 0.15).

CONCLUSION

Most HIV-positive patients treated for TB did not have culture-confirmed TB, and mortality tended to be higher in patients without culture-confirmed disease, although the association was not statistically different after adjusting for other variables. Accurate TB diagnosis in HIV-positive persons is crucial.

Myeloperoxidase inhibition in mice alters atherosclerotic lesion composition

Myeloperoxidase (MPO) is a highly abundant protein within the neutrophil that is associated with lipoprotein oxidation, and increased plasma MPO levels are correlated with poor prognosis after myocardial infarct. Thus, MPO inhibitors have been developed for the treatment of heart failure and acute coronary syndrome in humans. 2-(6-(5-Chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide PF-06282999 is a recently described selective small molecule mechanism-based inactivator of MPO. Here, utilizing PF-06282999, we investigated the role of MPO to regulate atherosclerotic lesion formation and composition in the Ldlr^-/- mouse model of atherosclerosis. Though MPO inhibition did not affect lesion area in Ldlr^-/- mice fed a Western diet, reduced necrotic core area was observed in aortic root sections after MPO inhibitor treatment. MPO inhibition did not alter macrophage content in and leukocyte homing to atherosclerotic plaques. To assess non-invasive monitoring of plaque inflammation, [¹⁸F]-Fluoro-deoxy-glucose (FDG) was administered to Ldlr^-/- mice with established atherosclerosis that had been treated with clinically relevant doses of PF-06282999, and reduced FDG signal was observed in animals treated with a dose of PF-06282999 that corresponded with reduced necrotic core area. These data suggest that MPO inhibition does not alter atherosclerotic plaque area or leukocyte homing, but rather alters the inflammatory tone of atherosclerotic lesions; thus, MPO inhibition could have utility to promote atherosclerotic lesion stabilization and prevent atherosclerotic plaque rupture.

2-Aminopyridine-Based Mitogen-Activated Protein Kinase Kinase Kinase Kinase 4 (MAP4K4) Inhibitors: Assessment of Mechanism-Based Safety

Studies have linked the serine-threonine kinase MAP4K4 to the regulation of a number of biological processes and/or diseases, including diabetes, cancer, inflammation, and angiogenesis. With a majority of the members of our lead series (e.g., 1) suffering from time-dependent inhibition (TDI) of CYP3A4, we sought design avenues that would eliminate this risk. One such approach arose from the observation that carboxylic acid-based intermediates employed in our discovery efforts retained high MAP4K4 inhibitory potency and were devoid of the TDI risk. The medicinal chemistry effort that led to the discovery of this central nervous system-impaired inhibitor together with its preclinical safety profile is described.

Magnetic behaviour of bimetallic layered phases M'0.2Mn0.8PS3·0.25 H2O (M' = ZnII, CuII, NiII, CoII)

In this work the magnetic properties of bimetallic phases M'_0.2Mn_0.8PS₃·0.25H₂O (M' = Co^II, Ni^II, Cu^II or Zn^II) have been explored and compared with those of the pristine phase MnPS₃. Magnetic susceptibility, high field magnetization and electron paramagnetic resonance (EPR) studies reveal that the transition temperature between the antiferromagnetic and paramagnetic order for the pristine phase is shifted to lower values in the bimetallic phases. From magnetization measurements the critical field of the spin-flop transition is found to be dependent on the nature of the added secondary transition metal ion. EPR spectra of all compounds in the temperature range of 8-300 K present a single resonance line shape. Temperature dependence of the EPR parameters, like line width, g values and double integrated area (I_DIN), are obtained from the spectra and present a scenario compatible with the magnetization results. The temperature dependence of the first derivative of the product (I_DINT) shows two maxima for all samples, with exception of the Co^II phase, indicating two critical temperatures, while these critical temperatures could not be clearly determined by dc susceptibility.

Outcomes of HIV-positive patients with cryptococcal meningitis in the Americas

BACKGROUND

Cryptococcal meningitis (CM) is associated with substantial mortality in HIV-infected patients. Optimal timing of antiretroviral therapy (ART) in persons with CM represents a clinical challenge, and the burden of CM in Latin America has not been well described. Studies suggest that early ART initiation is associated with higher mortality, but data from the Americas are scarce.

METHODS

HIV-infected adults in care between 1985-2014 at participating sites in the Latin America (the Caribbean, Central and South America network (CCASAnet)) and the Vanderbilt Comprehensive Care Clinic (VCCC) and who had CM were included. Survival probabilities were estimated. Risk of death when initiating ART within the first 2 weeks after CM diagnosis versus initiating between 2-8 weeks was assessed using dynamic marginal structural models adjusting for site, age, sex, year of CM, CD4 count, and route of HIV transmission.

FINDINGS

340 patients were included (Argentina 58, Brazil 138, Chile 28, Honduras 27, Mexico 34, VCCC 55) and 142 (42%) died during the observation period. Among 151 patients with CM prior to ART 56 (37%) patients died compared to 86 (45%) of 189 with CM after ART initiation (p=0.14). Patients diagnosed with CM after ART had a higher risk of death (p=0.03, log-rank test). The probability of survival was not statistically different between patients who started ART within 2 weeks of CM (7/24, 29%) vs. those initiating between 2-8 weeks (14/53, 26%) (p=0.96), potentially due to lack of power.

INTERPRETATION

In this large Latin-American cohort, patients with CM had very high mortality rates, especially those diagnosed after ART initiation. This study reflects the overwhelming burden of CM in HIV-infected patients in Latin America.

Myeloperoxidase Inhibition Improves Ventricular Function and Remodeling After Experimental Myocardial Infarction

•

The inflammatory enzyme MPO is a potential therapeutic target in cardiovascular diseases.

•

PF-1355 is an orally bioavailable mechanism-based inhibitor of MPO enzymatic activity. PF-1355 treatment successfully inhibited MPO in mouse models of myocardial infarction and ischemia reperfusion injury.

•

Short duration oral drug treatment for 7 days attenuated inflammation and cardiac dilation during early infarct healing. However, MPO-containing cells persisted beyond 7 days.

•

Prolonged 21-day treatment improved ejection fraction (∼44%) and decreased end-diastolic volume (∼53%) and left ventricular mass (∼33%) compared with untreated control subjects.

•

Better therapeutic effect was also achieved when treatment was started early (at 1 h) after the initial ischemic insult.

PF-1355 is an oral myeloperoxidase (MPO) inhibitor that successfully decreased elevated MPO activity in mouse myocardial infarction models. Short duration PF-1355 treatment for 7 days decreased the number of inflammatory cells and attenuated left ventricular dilation. Cardiac function and remodeling improved when treatment was increased to 21 days. Better therapeutic effect was further achieved with early compared with delayed treatment initiation (1 h vs. 24 h after infarction). In conclusion, PF-1355 treatment protected a mouse heart from acute and chronic effects of MI, and this study paves the way for future translational studies investigating this class of drugs in cardiovascular diseases.

Endothelial protein kinase MAP4K4 promotes vascular inflammation and atherosclerosis

Signalling pathways that control endothelial cell (EC) permeability, leukocyte adhesion and inflammation are pivotal for atherosclerosis initiation and progression. Here we demonstrate that the Sterile-20-like mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4), which has been implicated in inflammation, is abundantly expressed in ECs and in atherosclerotic plaques from mice and humans. On the basis of endothelial-specific MAP4K4 gene silencing and gene ablation experiments in Apoe(-/-) mice, we show that MAP4K4 in ECs markedly promotes Western diet-induced aortic macrophage accumulation and atherosclerotic plaque development. Treatment of Apoe(-/-) and Ldlr(-/-) mice with a selective small-molecule MAP4K4 inhibitor also markedly reduces atherosclerotic lesion area. MAP4K4 silencing in cultured ECs attenuates cell surface adhesion molecule expression while reducing nuclear localization and activity of NFκB, which is critical for promoting EC activation and atherosclerosis. Taken together, these results reveal that MAP4K4 is a key signalling node that promotes immune cell recruitment in atherosclerosis.

Discovery of an in Vivo Tool to Establish Proof-of-Concept for MAP4K4-Based Antidiabetic Treatment

Recent studies in adipose tissue, pancreas, muscle, and macrophages suggest that MAP4K4, a serine/threonine protein kinase may be a viable target for antidiabetic drugs. As part of the evaluation of MAP4K4 as a novel antidiabetic target, a tool compound, 16 (PF-6260933) and a lead 17 possessing excellent kinome selectivity and suitable properties were delivered to establish proof of concept in vivo. The medicinal chemistry effort that led to the discovery of these lead compounds is described herein together with in vivo pharmacokinetic properties and activity in a model of insulin resistance.

Methicillin-resistant Staphylococcus aureus infections among healthy full-term newborns

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged in the community, causing disease among healthy people lacking traditional risk factors for MRSA infection. This article describes an outbreak of MRSA among healthy full-term newborns.

DESIGN

Cases were identified and corresponding medical information collected. Telephone interviews were conducted with mothers of cases and surveillance cultures from mothers and newborns were performed. MRSA isolates were genotyped.

SETTING

Hospital in Chicago, Illinois, USA.

PARTICIPANTS

Newborns, their mothers and hospital healthcare workers.

INTERVENTION

Nursery infection control practices were enhanced. The MRSA-colonised healthcare workers received intranasal mupirocin.

MAIN OUTCOME

Within 4-23 days of birth, 11 newborns were identified with pustules, vesicles or blisters located on the head, groin, perineum, ears, legs, chin and trunk. All received antimicrobials and recovered without incident.

RESULTS

None of 432 peripartum women, one of 399 newborns, and two of 135 healthcare workers were nasal MRSA carriers. Available isolates from six patients, two healthcare workers, and one from an MRSA-colonised newborn were similar by pulsed-field gel electrophoresis. Other than contact with the hospital, no common exposures of MRSA transmission were identified.

CONCLUSIONS

MRSA strains that initially emerged in the community are now causing disease in healthcare settings. Providers should be aware that MRSA can cause skin infections among healthy newborns. Adherence to standard infection control practices is important to prevent transmission of MRSA in nurseries.

Cytomegalovirus Infections in Cardiac Transplant Patients: An Experience at a Clinical Hospital, University of Chile

BACKGROUND

Since cytomegalovirus (CMV) infects between 20% and 50% of heart transplant patients, we reviewed our experience in 7 cases of this infection.

METHODS

A prospective analysis of CMV infection was performed in heart transplant patients who received cyclosporine, azathioprine, or mycophenolate mofetil, and prednisone. An elevated creatinine de novo was managed with antibody induction.

RESULTS

Between August 2001 and December 2005, we performed 22 heart transplants and 1 heart plus kidney transplant. Twenty-two patients were positive for CMV before transplantation. One patient died early because of graft failure. Immunosuppression included cyclosporine and prednisone (100%), azathioprine (52%), or mycophenolate (47%). Two recipients were induced with thymoglobulin and 13 with Daclizumab, while 8 did not receive any antibody. Nineteen patients received prophylaxis for CMV. Seven patients (30%) showed CMV infection, 6 of whom had received prophylaxis. Symptoms started at an average of 107 days posttransplantation in patients with prophylaxis. Three patients had gastritis, 2 pneumonia, and 1 colitis. One patient had concomitant lung aspergillosis. The two patients who received ATG developed CMV infections; 3 of the 12 with Daclizumab; and 2 who did not receive antibody. Of the CMV-infected subjects, 5 were on azathioprine and 2 on mycophenolate. All patients were treated with gancyclovir. The 1 patient with concomitant aspergillosis died.

CONCLUSIONS

The incidence of infection by CMV was 30%. Prophylaxis seemed to delay infection. Daclizumab induction did not increase the risk for CMV.

Ewes increase their intake when offered a choice of herbage species at pasture

In stall-feeding conditions, food diversity has been shown to increase an animal's motivation to eat and its level of food intake. This effect has also been suggested, but not demonstrated, for free-grazing animals. In free-grazing conditions, however, animals may have to search for the preferred plant species and this may reduce their intake rate. Moreover, the management of diverse swards faces a risk of overgrazing the preferred species and undergrazing the less preferred species, leading to resource degradation. We investigated the effect of food diversity on foraging behaviour and intake in grazing sheep, in interaction with the type of diversity (conterminal monoculturesv. mixtures) and management (two monocultures offered simultaneouslyv. successively over time). Five treatments were compared with five groups of five dry INRA 401 ewes for five periods, using a Latin-square design: LOL=grazing a monoculture ofLolium perenne cv.Herbie (L); FES=grazing a monoculture ofFestuca arundinacea cv.Florine (F); STRIPS=grazing conterminal monocultures of L and F, 0·5:0·5 by ground area, with animals having a free choice between both species; TIME=grazing L from 16:00 to 09:00 h and F from 09:00 to 16:00 h; MIX=grazing an intermeshed mixture of L and F. Sward height was maintained at 9 cm. Each period comprised a 5-day adaptation subperiod followed by a 5-day measurement subperiod. Dietary choices and intake were measured usingn-alkanes, and grazing time was assessed using the Ethosys®recording system. Intake rate was calculated as the ratio of intake to grazing time. Intake in the monoculture treatments were higher than predictions made for housed animals given similar foragesad libitum, demonstrating that sward conditions were favourable for the expression of voluntary intake in all treatments. Intake was higher in LOL than in FES, this result being consistent with predictions for stall-feeding conditions. There was no difference in diet composition, foraging behaviour and intake between the bispecific treatments (STRIPS, TIME and MIX). Intake was higher in the bispecific treatments than in LOL (1666v. 1492 g digestible organic matter per day,P<0·001). Grazing time was higher in STRIPS and MIX than in LOL (420 and 430 min respectivelyv. 366 min,P<0·01). Dry ewes increase their intake when offered a choice of herbage species at pasture, this being mediated via an increase in grazing time rather than an increase in intake rate. There was no interaction with type of diversity or type of management.

Influence of the intensity, level and phase of spinal cord injury on the proliferation of T cells and T-cell-dependent antibody reactions in rats

STUDY DESIGN

Three independent experiments in a rat model of contusive spinal cord (SC) injury were performed. Two studied the alterations induced by SC injury on some immunological aspects of the T-cell response. The third one evaluated the motor recovery of rats with low-thoracic injuries.

OBJECTIVE

To examine the effect of level, intensity and phase of SC injury on T-cell proliferation and T-cell-dependent antibody response.

SETTING

Neuroimmunology Department, UIMEN, IMSS-CAMINA Research Center.

METHODS

Lymphocyte proliferation and hemagglutination assays were performed. Animals were injured either moderately or severely at T1 or T12 SC segments. Analysis of peripheral T-cell proliferation in response to mitogens and to myelin basic protein (MBP), as well as of antibody production against a T-dependent antigen, was performed at acute, subacute and chronic phases.

RESULTS

A significant decrease of both response to mitogens and antibody production was found especially during the acute phase and in animals with severe and high (T1)-level injury. Animals with low (T12) and moderate contusions recovered to control levels at the chronic phase. An autoimmune reaction against MBP was observed only in animals with severe contusion at low level.

CONCLUSIONS

The intensity, level and phase of SC injury differentially alter the function of T cells. These results will allow a better interpretation of studies directed to elucidate the role of T lymphocytes in various processes developed after SC injury.

Sodium vitamin C cotransporter SVCT2 is expressed in hypothalamic glial cells

Kinetic analysis of vitamin C uptake demonstrated that different specialized cells take up ascorbic acid through sodium-vitamin C cotransporters. Recently, two different isoforms of sodium-vitamin C cotransporters (SVCT1/SLC23A1 and SVCT2/SLC23A2) have been cloned. SVCT2 was detected mainly in choroidal plexus cells and neurons; however, there is no evidence of SVCT2 expression in glial and endothelial cells of the brain. Certain brain locations, including the hippocampus and hypothalamus, consistently show higher ascorbic acid values compared with other structures within the central nervous system. However, molecular and kinetic analysis addressing the expression of SVCT transporters in cells isolated from these specific areas of the brain had not been done. The hypothalamic glial cells, or tanycytes, are specialized ependymal cells that bridge the cerebrospinal fluid with different neurons of the region. Our hypothesis postulates that SVCT2 is expressed selectively in tanycytes, where it is involved in the uptake of the reduced form of vitamin C (ascorbic acid), thereby concentrating this vitamin in the hypothalamic area. In situ hybridization and optic and ultrastructural immunocytochemistry showed that the transporter SVCT2 is highly expressed in the apical membranes of mouse hypothalamic tanycytes. A newly developed primary culture of mouse hypothalamic tanycytes was used to confirm the expression and function of the SVCT2 isoform in these cells. The results demonstrate that tanycytes express a high-affinity transporter for vitamin C. Thus, the vitamin C uptake mechanisms present in the hypothalamic glial cells may perform a neuroprotective role concentrating vitamin C in this specific area of the brain.

Residual behavioral and neuroanatomical effects of short-term chronic ethanol consumption in rats

The residual effects of short-term chronic ethanol consumption were investigated in rats maintained on an ethanol liquid diet for 26 consecutive days (mean intake = 16.1 g/kg/day). Animals were assessed for spontaneous motor activity (12 days post-ethanol), spatial working memory (17 days post-ethanol), spatial reference memory (184 days post-ethanol), and retention of passive avoidance (201 days post-ethanol). Measurements of brain weights and cortical thickness vertices within the dorsomedial and ventrolateral cortex of eight coronal planes were determined 260 days post-ethanol. Two-dimensional cell profile densities within six coronal planes and within CA1 region of the hippocampus were also obtained, along with the total volumetric measurement of the hippocampus proper. Results indicated between group differences when subjects were assessed on working memory with ethanol-treated animals exhibiting longer escape latencies in a Morris water maze, an effect partially attributed to the perseverance of ethanol-treated animals in exhibiting thigmotaxicity. No other ethanol-related behavioral impairment was noted. Neuroanatomically, ethanol-treated rats had thinner cortical mantles (6.3% and 6.6% reductions) within the frontoparietal cortex and had lower two-dimensional cell profile densities within the most caudal cortical region studied. Interestingly, control animals with thicker cortical mantles tended to perform better on the working memory task, whereas the opposite was true for ethanol-treated subjects. These data led to the conclusion that chronic ethanol consumption of a relatively short duration produces working memory impairments, albeit mild, that are partially related to an inability to abandon ineffectual behavioral strategies, and also produces neuroanatomical alterations within the cortex.

Circumsporozoite protein is required for development of malaria sporozoites in mosquitoes

Malaria parasites undergo a sporogonic cycle in the mosquito vector. Sporozoites, the form of the parasite injected into the host during a bloodmeal, develop inside oocysts in the insect midgut, then migrate to and eventually invade the salivary glands. The circumsporozoite protein (CS), one of the major proteins synthesized by salivary gland sporozoites, is a surface-associated molecule which is important in sporozoite infectivity to the host. Here, by gene targeting, we created Plasmodium berghei lines in which the single-copy CS gene was disrupted. The CS(-) and wild-type parasites produced similar numbers of oocysts of comparable size in the mosquito midgut. In the CS(-) oocysts, however, sporozoite formation was profoundly inhibited. CS therefore appears to have a pleiotropic role and to be vital for malaria parasites in both the vector and the host: in mosquitoes, CS is essential for sporozoite development within oocysts, and in the vertebrate host it promotes sporozoite attachment to hepatocytes.

Effects of a whole-body resistive training regimen in the elderly

Twenty active elderly subjects (mean age = 66.4 years, range 51-81) participated in a 12-week weight-training program to determine the possibility of increasing muscular strength and lean body weight. The training utilized variable resistance weight machines which trained the major muscle groups. The male subjects (n = 11) experienced an average increase of 66.1% (SD = 19.39, p < 0.00001) in total maximum weight lifted while the females (n = 9) showed an average increase of 72.2% (SD = 33.44, p < 0.001). Lean body weight, which was calculated by skinfold measurements for each group did increase, but was not statistically significant (males p < 0.11, females p < 0.18). The study demonstrated the positive effects a weight-training regimen can have on an elderly population.

[Diagnosis of gastroesophageal reflux by radioisotopic techniques]

We evaluated 148 patients (mean age 45 years) with clinically evident gastroesophageal reflux. A radioisotopic test with 99mTc sulphur-colloid was performed in all; endoscopy in 146, biopsy in 24, acid reflux test and manometric evaluation in 141 and radiologic studies in 85. Sensitivity of the different techniques was: radioisotopes 92%, radiology 87%, acid reflux test 84%; endoscopy 63% and manometric studies 61%. Severity of reflux and esophagitis was adequately predicted from radioisotopic evaluation. We conclude that this radioisotopic test is highly reliable for the diagnosis of gastroesophageal reflux.

Allergenic cross-reactivity among pollens of Urticaceae

Common antigenic determinants have been observed between Parietaria and Urtica dioica pollen. The four Parietaria pollens selected (P. judaica, P. officinalis, P. lusitanica and P. mauritanica) are shown to possess a high allergenic homology. IgE-binding structures, homologous to the P. judaica main allergenic polypeptide (Pj10), were found in the other species by immunodetection. Monoclonal antibodies specific to the Pj10 polypeptide recognized proteins from the four Parietaria pollens. Skin prick test and RAST inhibition yielded results that also indicated a high allergenic cross-reactivity among these pollens, with homologous peptides bearing common antigenic and allergenic determinants. On the other hand, U. dioica pollen showed only a slight allergenic similarity to Parietaria. The potential allergenic activity of these pollens is discussed.