Immunocytoprotection after reperfusion with Kv1.3 inhibitors has an extended treatment window for ischemic stroke

Introduction: Mechanical thrombectomy has improved treatment options and outcomes for acute ischemic stroke with large artery occlusion. However, as the time window of endovascular thrombectomy is extended there is an increasing need to develop immunocytoprotective therapies that can reduce inflammation in the penumbra and prevent reperfusion injury. We previously demonstrated, that by reducing neuroinflammation, KV1.3 inhibitors can improve outcomes not only in young male rodents but also in female and aged animals. To further explore the therapeutic potential of KV1.3 inhibitors for stroke therapy, we here directly compared a peptidic and a small molecule KV1.3 blocker and asked whether KV1.3 inhibition would still be beneficial when started at 72 hours after reperfusion. Methods: Transient middle cerebral artery occlusion (tMCAO, 90-min) was induced in male Wistar rats and neurological deficit assessed daily. On day-8 infarction was determined by T2-weighted MRI and inflammatory marker expression in the brain by quantitative PCR. Potential interactions with tissue plasminogen activator (tPA) were evaluated in-vitro with a chromogenic assay. Results: In a direct comparison with administration started at 2 hours after reperfusion, the small molecule PAP-1 significantly improved outcomes on day-8, while the peptide ShK-223 failed to reduce infarction and neurological deficits despite reducing inflammatory marker expression. PAP-1 still provided benefits when started 72 hours after reperfusion. PAP-1 does not reduce the proteolytic activity of tPA. Discussion: Our studies suggest that KV1.3 inhibition for immunocytoprotection after ischemic stroke has a wide therapeutic window for salvaging the inflammatory penumbra and requires brain-penetrant small molecules.

Repurposing the KCa3.1 Blocker Senicapoc for Ischemic Stroke

Senicapoc, a small molecule inhibitor of the calcium-activated potassium channel KCa3.1, was safe and well-tolerated in clinical trials for sickle cell anemia. We previously reported proof-of-concept data suggesting that both pharmacological inhibition and genetic deletion of KCa3.1 reduces infarction and improves neurologic recovery in rodents by attenuating neuroinflammation. Here we evaluated the potential of repurposing senicapoc for ischemic stroke. In cultured microglia, senicapoc inhibited KCa3.1 currents with an IC50 of 7 nM, reduced Ca2+ signaling induced by the purinergic agonist ATP, suppressed expression of pro-inflammatory cytokines and enzymes (iNOS and COX-2), and prevented induction of the inflammasome component NLRP3. When transient middle cerebral artery occlusion (tMCAO, 60 min) was induced in male C57BL/6 J mice, twice daily administration of senicapoc at 10 and 40 mg/kg starting 12 h after reperfusion dose-dependently reduced infarct area determined by T2-weighted magnetic resonance imaging (MRI) and improved neurological deficit on day 8. Ultra-high-performance liquid chromatography/mass spectrometry analysis of total and free brain concentrations demonstrated sufficient KCa3.1 target engagement. Senicapoc treatment significantly reduced microglia/macrophage and T cell infiltration and activation and attenuated neuronal death. A different treatment paradigm with senicapoc started at 3 h and MRI on day 3 and day 8 revealed that senicapoc reduces secondary infarct growth and suppresses expression of inflammation markers, including T cell cytokines in the brain. Lastly, we demonstrated that senicapoc does not impair the proteolytic activity of tissue plasminogen activator (tPA) in vitro. We suggest that senicapoc could be repurposed as an adjunctive immunocytoprotective agent for combination with reperfusion therapy for ischemic stroke.

Abstract WP219: Repurposing The K Ca 3.1 Inhibitor Senicapoc For Treatment Of Acute Ischemic Stroke

Background: Acute ischemic stroke (AIS) is a leading cause of death and long-term disability. Both microglia (MG) and infiltrating macrophages (MP) are critical effector cell types in ischemic brain injury and recovery. K Ca 3.1 is a calcium-activated potassium channel that is upregulated in reactive MG and MP. Studies using either genetic deletion or pharmacological inhibition of K Ca 3.1 demonstrated that this channel is critical for pro-inflammatory activation of MG/MP as well as exacerbation of stroke pathophysiology. Senicapoc (ICA-17043) is a K Ca 3.1-specific inhibitor that has been used in human clinical trials for non-neurological indications (sickle cell anemia, asthma) and was proven safe. Here we evaluate the potential for repurposing senicapoc for AIS.

Methods: Young adult male and female mice underwent 60 min middle cerebral artery occlusion (MCAO)/reperfusion. MCAO was monitored by laser doppler. Senicapoc’s pharmacokinetic (PK) profile was determined using high performance liquid chromatography - mass spectroscopy. Drug levels in plasma and brain were quantified at multiple time points post administration. Effects of senicapoc on post-stroke release of cytokines/chemokines was determined by multiplex ELISA. Inflammatory infiltrates were quantified with flow cytometry. Efficacy studies included: (i) infarct volume (MRI T2), white matter integrity (DTI) and longitudinal neurobehavioral outcomes (NBO). In-vitro chromogenic assay was used to assess senicapoc’s effect on proteolytic activity of tissue plasminogen activator (tPA).

Results: Administration of senicapoc (40 mg/kg, i.p.) twice daily for seven days starting 12 h after MCAO resulted in ~55% reduction in infarct volume with corresponding improvements in NBO. Free senicapoc levels in brain ranged from 20 - 200 nM in stroked mice at 1, 4 & 12 hours following administration. All values exceeded senicapoc’s IC 50 (11 nM) for K Ca 3.1. Senicapoc, at up to 5 μM, had no effect on tPA’s proteolytic activity.

Conclusions: We provide proof-of-concept data that senicapoc, administered in an extended temporal window, can markedly reduce infarct volume and improve NBO in a mouse model of AIS. Senicapoc demonstrated favorable PK and CNS penetration. It did not interfere with tPA.

The seizure-inducing plastic explosive RDX inhibits the α1β2γ2 GABAA receptor

Objective

Royal demolition explosive (RDX) can induce seizures in wildlife and humans following release into the environment or after voluntary consumption. During the Vietnam War, RDX intoxication was the most common cause of generalized seizures in US service personnel, and in some sections of the armed forces, eating of RDX has continued as “a dare” to this day. After its mechanism of action was long unknown, RDX was recently shown to be a GABA_A receptor antagonist. We here determined the GABA_A receptor subtype‐selectivity of RDX and mapped its functional binding site.

Methods

We used whole‐cell patch‐clamp to determine the potency of RDX on 10 recombinantly expressed GABA_A receptors and mapped the RDX binding site using a combination of Rosetta molecular modeling and site‐directed mutagenesis.

Results

RDX was found to reversibly inhibit the α1β2γ2 GABA_A receptor with an IC₅₀ of 23 μmol/L (95% CI 15.1–33.3 μmol/L), whereas α4 and α6 containing GABA_A receptor combinations were 4–10‐fold less sensitive. RDX is binding to the noncompetitive antagonist (NCA) site in the pore. In a molecular model based on the cryo‐EM structure of the resting state of the α1β2γ2 receptor, RDX forms two hydrogen bonds with the threonines at the T6’ ring and makes hydrophobic interactions with the valine and alanine in 2′ position of the α1 or β2 subunits.

Interpretation

Our findings characterize the mechanism of action of RDX at the atomistic level and suggest that RDX‐induced seizures should be susceptible to treatment with GABA_A modulating drugs such as benzodiazepines, barbiturates, propofol, or neurosteroids.

An in vivo Cell-Based Delivery Platform for Zinc Finger Artificial Transcription Factors in Pre-clinical Animal Models

Zinc finger (ZF), transcription activator-like effectors (TALE), and CRISPR/Cas9 therapies to regulate gene expression are becoming viable strategies to treat genetic disorders, although effective in vivo delivery systems for these proteins remain a major translational hurdle. We describe the use of a mesenchymal stem/stromal cell (MSC)-based delivery system for the secretion of a ZF protein (ZF-MSC) in transgenic mouse models and young rhesus monkeys. Secreted ZF protein from mouse ZF-MSC was detectable within the hippocampus 1 week following intracranial or cisterna magna (CM) injection. Secreted ZF activated the imprinted paternal Ube3a in a transgenic reporter mouse and ameliorated motor deficits in a Ube3a deletion Angelman Syndrome (AS) mouse. Intrathecally administered autologous rhesus MSCs were well-tolerated for 3 weeks following administration and secreted ZF protein was detectable within the cerebrospinal fluid (CSF), midbrain, and spinal cord. This approach is less invasive when compared to direct intracranial injection which requires a surgical procedure.

Identification of the Functional Binding Site for the Convulsant Tetramethylenedisulfotetramine in the Pore of the α 2 β 3 γ 2 GABAA Receptor

Tetramethylenedisulfotetramine (TETS) is a so-called "caged" convulsant that is responsible for thousands of accidental and malicious poisonings. Similar to the widely used GABA receptor type A (GABA_A) antagonist picrotoxinin, TETS has been proposed to bind to the noncompetitive antagonist (NCA) site in the pore of the receptor channel. However, the TETS binding site has never been experimentally mapped, and we here set out to gain atomistic level insights into how TETS inhibits the human α ₂ β ₃ γ ₂ GABA_A receptor. Using the Rosetta molecular modeling suite, we generated three homology models of the α ₂ β ₃ γ ₂ receptor in the open, desensitized, and closed/resting state. Three different ligand-docking algorithms (RosettaLigand, Glide, and Swissdock) identified two possible TETS binding sites in the channel pore. Using a combination of site-directed mutagenesis, electrophysiology, and modeling to probe both sites, we demonstrate that TETS binds at the T6' ring in the closed/resting-state model, in which it shows perfect space complementarity and forms hydrogen bonds or makes hydrophobic interactions with all five pore-lining threonine residues of the pentameric receptor. Mutating T6' in either the α ₂ or β ₃ subunit reduces the IC₅₀ of TETS by ∼700-fold in whole-cell patch-clamp experiments. TETS is thus interacting at the NCA site in the pore of the GABA_A receptor at a location that is overlapping but not identical to the picrotoxinin binding site. SIGNIFICANCE STATEMENT: Our study identifies the binding site of the highly toxic convulsant tetramethylenedisulfotetramine (TETS), which is classified as a threat agent by the World Health Organization. Using a combination of homology protein modeling, ligand docking, site-directed mutagenesis, and electrophysiology, we show that TETS is binding in the pore of the α₂β₃γ₂ GABA receptor type A receptor at the so-called T6' ring, wherein five threonine residues line the permeation pathway of the pentameric receptor channel.

Translational outcomes in a full gene deletion of ubiquitin protein ligase E3A rat model of Angelman syndrome

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by developmental delay, impaired communication, motor deficits and ataxia, intellectual disabilities, microcephaly, and seizures. The genetic cause of AS is the loss of expression of UBE3A (ubiquitin protein ligase E6-AP) in the brain, typically due to a deletion of the maternal 15q11-q13 region. Previous studies have been performed using a mouse model with a deletion of a single exon of Ube3a. Since three splice variants of Ube3a exist, this has led to a lack of consistent reports and the theory that perhaps not all mouse studies were assessing the effects of an absence of all functional UBE3A. Herein, we report the generation and functional characterization of a novel model of Angelman syndrome by deleting the entire Ube3a gene in the rat. We validated that this resulted in the first comprehensive gene deletion rodent model. Ultrasonic vocalizations from newborn Ube3am-/p+ were reduced in the maternal inherited deletion group with no observable change in the Ube3am+/p- paternal transmission cohort. We also discovered Ube3am-/p+ exhibited delayed reflex development, motor deficits in rearing and fine motor skills, aberrant social communication, and impaired touchscreen learning and memory in young adults. These behavioral deficits were large in effect size and easily apparent in the larger rodent species. Low social communication was detected using a playback task that is unique to rats. Structural imaging illustrated decreased brain volume in Ube3am-/p+ and a variety of intriguing neuroanatomical phenotypes while Ube3am+/p- did not exhibit altered neuroanatomy. Our report identifies, for the first time, unique AS relevant functional phenotypes and anatomical markers as preclinical outcomes to test various strategies for gene and molecular therapies in AS.

Adverse Childhood Experiences and Health and Wellness Outcomes among Black Men Who Have Sex with Men

Black men who have sex with men (BMSM) are a population at the intersection of two minority statuses-racial minority and sexual minority. Membership in either group, compared to white or heterosexual group membership, may increase one's risk of negative childhood and adult experiences. Baseline data from an HIV intervention efficacy trial (the Black Men Evolving Study) were used to explore the prevalence of adverse childhood experiences (ACEs) among 536 BMSM and associations between ACEs and adult mental and physical health outcomes. Overall, the prevalence of ACEs was high among this sample of BMSM with almost 90% experiencing at least one ACE. Findings revealed that ACE score was significantly associated with adult mental health (AOR = 1.21, 95% CI [1.12, 1.30]), but not with adult physical health. All ACEs were significantly associated with mental health, but only physical neglect and household substance abuse were significantly associated with physical health (AOR = 1.69, 95% CI [1.02, 2.74] and AOR = 1.57, 95% CI [1.03, 2.40], respectively). The findings support the need for interventions targeting improved adult health outcomes, particularly for minority groups, to consider the impact of early adversity on health and wellness.

The effect of time-of-day dosing on the pharmacokinetics and pharmacodynamics of dexlansoprazole MR: evidence for dosing flexibility with a Dual Delayed Release proton pump inhibitor

BACKGROUND

Dexlansoprazole MR is a Dual Delayed Release proton pump inhibitor formulated to extend the duration of acid suppression.

AIM

To evaluate the pharmacokinetics and pharmacodynamics of dexlansoprazole MR dosed before 4 different meal times.

METHODS

In this randomized, open-label, four-way crossover study, 48 healthy subjects received dexlansoprazole MR 60 mg once daily 30 min before breakfast, lunch, dinner or an evening snack. Pharmacokinetics of dexlansoprazole MR and intragastric pH were assessed over a 24-h postdose interval on day 5 for each regimen.

RESULTS

Absorption was delayed when dexlansoprazole MR was administered before each regimen relative to breakfast; however, systemic exposures of dexlansoprazole at all regimens were bioequivalent. There were no statistically significant differences in mean 24-h intragastric pH between dosing before dinner or an evening snack vs. breakfast; however, there was a small (0.2), but statistically significant difference between lunch and breakfast. There was a statistically significant difference of 7 percentage points in the percentage of time intragastric pH was >4 for the snack regimen relative to the breakfast regimen, but there were no statistically significant differences between lunch or dinner compared with breakfast.

CONCLUSION

Dexlansoprazole MR provides comparable acid control when administered at different times of the day.

Clinical trial: the effect and timing of food on the pharmacokinetics and pharmacodynamics of dexlansoprazole MR, a novel Dual Delayed Release formulation of a proton pump inhibitor--evidence for dosing flexibility

BACKGROUND

Dexlansoprazole MR is a proton pump inhibitor with a Dual Delayed Release (DDR) formulation designed to prolong the dexlansoprazole plasma concentration-time profile. The presence of food or time of dosing relative to food may affect dexlansoprazole absorption.

AIMS

To evaluate the effect of food on the pharmacokinetics (PK) and pharmacodynamics (PD) of dexlansoprazole following oral administration of dexlansoprazole MR.

METHODS

In this open-label, single-dose, randomized, 4-way crossover study, 48 healthy subjects received placebo (day 1) and dexlansoprazole MR 90 mg (day 3) after fasting, 5 or 30 min before a high-fat breakfast, or 30 min after a high-fat breakfast. Intragastric pH (days 1 and 3) and PK (day 3) of dexlansoprazole were assessed over a 24-h interval after each dose.

RESULTS

Following administration of dexlansoprazole MR under fasted/fed conditions, mean dexlansoprazole plasma concentration-time profiles generally exhibited two distinct peaks, resulting from the DDR formulation. Increases in dexlansoprazole maximum plasma concentration (12-31%) and area under the plasma concentration-time curve (9-21%) were observed with the fed regimens; however, differences in intragastric pH were not considered clinically relevant.

CONCLUSION

Dexlansoprazole MR can be administered without regard to food or the timing of food in most patients.

Identification of Transcripts Involved in Resistance Responses to Leaf Spot Disease Caused by Cercosporidium personatum in Peanut (Arachis hypogaea)

ABSTRACT Late leaf spot disease caused by Cercosporidium personatum is one of the most destructive foliar diseases of peanut (Arachis hypogaea) worldwide. The objective of this research was to identify resistance genes in response to leaf spot disease using microarray and real-time polymerase chain reaction (PCR). To identify transcripts involved in disease resistance, we studied the gene expression profiles in two peanut genotypes, resistant or susceptible to leaf spot disease, using cDNA microarray containing 384 unigenes selected from two expressed sequenced tag (EST) cDNA libraries challenged by abiotic and biotic stresses. A total of 112 spots representing 56 genes in several functional categories were detected as up-regulated genes (log(2) ratio > 1). Seventeen of the top 20 genes, each matching gene with known function in GenBank, were selected for validation of their expression levels using real-time PCR. The two peanut genotypes were also used to study the functional analysis of these genes and the possible link of these genes to the disease resistance trait. Microarray technology and real-time PCR were used for comparison of gene expression. The selected genes identified by microarray analysis were validated by real-time PCR. These genes were more greatly expressed in the resistant genotype as a result of response to the challenge of C. personatum than in the susceptible genotype. Further investigations are needed to characterize each of these genes in disease resistance. Gene probes could then be developed for application in breeding programs for marker-assisted selection.

Mapping microbial biodiversity

We report the development of a prototype database that "maps" microbial diversity in the context of the geochemical and geological environment and geographic location. When it is fully implemented, scientists will be able to conduct database searches, construct maps containing the information of interest, download files, and enter data over the Internet.

Should all infertile males undergo urologic evaluation before assisted reproductive technologies? Two cases of testicular cancer presenting with infertility

OBJECTIVE

To report two cases of testicular cancer in patients presenting with infertility.

DESIGN

Case reports.

SETTING

University-affiliated urology practice.

PATIENT(S)

Two men presenting with infertility.

INTERVENTION(S)

Complete history and physical, hormonal assays, semen analysis, scrotal ultrasound, radical orchiectomy.

MAIN OUTCOME MEASURE(S)

Testicular pathology specimens.

RESULT(S)

Testicular cancer was diagnosed in two men sent to a urology clinic for infertility treatment.

CONCLUSION(S)

A thorough evaluation should be completed in all males in couples presenting with infertility.

Effects of ochratoxin A on cytotoxicity and cell differentiation in cultured rat embryonic cells

In the present study, the effects of ochratoxin A (OTA) on cytotoxicity, cell differentiation, and other cell functions in the embryonic midbrain cells, which are dopaminergic, were compared to those in the limb bud cells, which are nondopaminergic, to assess the selectivity of OTA central action. Twelve-day rat embryo midbrain and limb bud cells were cultured in Dulbecco's modified Eagle's medium nutrient and Ham's F12 (1:1) mix ture containing 10% Nuserum for 96 h in the presence of various concentrations of OTA. OTA signicfiantly reduced the levels of protein, DNA and glutathione, and [H]thymidine incorporation into DNA in both embryonic midbrain and limb bud cells in a similar concentration-dependent manner. The IC50 values for cytotoxicity measured by neutral red uptake were 1.10 microM in the midbrain cells and 1.05 microM in the limb bud cells. The IC50 values of cell differentiation were 1.10 microM in the midbrain cells and 1.0 microM in the limb bud cells. The addition of exogenous glutathione (32.5 microM) did not change the OTA-induced fall in protein and DNA levels, or the IC50 values of cytotoxicity and differentiation in the midbrain and limb bud cells. Data show that OTA does not appear to exert a selective toxic dopaminergic cell action and that OTA-induced cytotoxicity and inhibition of cell differentiation were not prevented by exogenous glutathione.

In vitro metabolism of the HIV-1 protease inhibitor ABT-378: species comparison and metabolite identification

HIV protease inhibitor ABT-378 (ABT-378) was metabolized very extensively and rapidly by liver microsomes from mouse, rat, dog, monkey, and humans. The rates of NADPH-dependent metabolism of ABT-378 ranged from 2.39 to 9.80 nmol.mg microsomal protein-1.min-1, with monkey liver microsomes exhibiting the highest rates of metabolism. ABT-378 was metabolized to 12 metabolites (M-1 to M-12), which were characterized by mass and NMR spectroscopy. The metabolite profile of ABT-378 in liver microsomes from all five species was similar, except that the mouse liver microsomes did not form M-9, a minor secondary metabolite. The predominant site of metabolism was the cyclic urea moiety of ABT-378. In all five species, the major metabolites were M-1 (4-oxo-ABT-378) and M-3 and M-4 (4-hydroxy-ABT-378). Metabolite M-2 (6-hydroxy-ABT-378) was formed by rodents at a faster rate than by dog, monkey, and human liver microsomes. Metabolites M-5 to M-8 were identified as monohydroxylated derivatives of ABT-378. Metabolites M-9 and M-10 were identified as hydroxylated products of M-1. Metabolites M-11 and M-12 were identified as dihydroxylated derivatives of ABT-378. The metabolite profile in human hepatocytes and liver slices was similar to that of human liver microsomes. The results of the current study indicate that ABT-378 is highly susceptible to oxidative metabolism in vitro, and possibly in vivo, in humans.

Effects of severe hypoxemia on mesenteric blood flow in neonatal piglets

BACKGROUND

The purpose of this work was to determine the effects of hypoxemia on systemic hemodynamic variables and regional conduit arterial blood flows in neonatal piglets.

MATERIALS AND METHODS

Using transit time blood flow probes, cardiac output and cranial mesenteric artery blood flow were monitored in groups of prematurely delivered (90% of term gestational age) and 2-week-old piglets prior to, during, and after exposure to a 30-min hypoxic (FIO2 = 0.12) challenge.

RESULTS

The documented alterations in systemic mean arterial pressure and cardiac output pressure during hypoxia and reoxygenation were consistent with the maturational age of the animals. In response to hypoxia, all animals demonstrated significant reductions in mesenteric blood flow, with returns to baseline levels during the 30-min reoxygenation phase. In still other prematurely delivered piglets, nutrient mesenteric arterial blood flows were measured using in vivo videomicroscopy. The marked hypoxemia-induced decline in mucosal blood flow was reversed by reoxygenation.

CONCLUSIONS

The physiologic mechanisms responsible for neonatal mesenteric vasoactive responsiveness are present in conduit and in nutrient vessels well prior to birth and can be activated by a significant perturbation. These observations are germane insofar as they provide a stable, age-matched acute animal model to study neonatal intestinal ischemic diseases, including necrotizing enterocolitis.

Neither dopamine nor dobutamine corrects mesenteric blood flow depression caused by positive end-expiratory pressure in a rat model of acute lung injury

OBJECTIVE

To determine if either dopamine or dobutamine would counteract the deleterious effect that positive end-expiratory pressure (PEEP) has on cardiac output and mesenteric blood flow in a rat model of acute lung injury.

DESIGN

Prospective, randomized, controlled trial in a clinically relevant model of acute lung injury.

SETTING

Microcirculation research laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

The animals were anesthetized with pentobarbital (30 mg/kg) by intraperitoneal injection. They underwent tracheostomy, jugular and femoral vein cannulation, femoral artery cannulation, carotid artery thermistor placement, and bowel preparation for in vivo video microscopy. Acute lung injury was created by administering 0.1 N hydrochloric acid (1 mL/kg) via the tracheostomy. Dopamine or dobutamine (2.5 or 12.5 microg/kg/min), followed by two intravenous fluid boluses, was administered to rats ventilated with 5, 10, 15, and 20 cm H2O of PEEP.

MEASUREMENTS AND MAIN RESULTS

Mean arterial pressure, thermodilution cardiac output, mesenteric arteriolar diameter, and red blood cell velocity were measured and mesenteric blood flow was calculated. Cardiac output was depressed in rats exposed to 20 cm H2O of PEEP by 32+/-2%. The corresponding values for cardiac output depression at 20 cm H2O of PEEP in rats receiving 2.5 and 12.5 microg/kg/min of dopamine and 2.5 and 12.5 microg/kg/min of dobutamine were 31+/-1%, 21+/-1%, 29+/-0%, and 24+/-2%, respectively. Mesenteric blood flow was depressed in rats ventilated with 20 cm H2O of PEEP by 74+/-3%, while the corresponding values in rats exposed to 20 cm H2O of PEEP and receiving 2.5 or 12.5 microg/kg/min of dopamine or 2.5 or 12.5 microg/kg/min of dobutamine were 86+/-3%, 77+/-3%, 73+/-3%, and 66+/-3%, respectively. Fluid boluses did not correct the deficits in cardiac output or mesenteric blood flow caused by the combination of acute lung injury and PEEP.

CONCLUSIONS

The higher doses of dopamine and dobutamine partially, but insignificantly, corrected the cardiac output depression caused by PEEP in a model of acute lung injury. Neither dose of dopamine nor dobutamine was able to improve PEEP-induced mesenteric blood flow depression.

Polypharmacy: a case report and new protocol for management

BACKGROUND

Polypharmacy is an important issue in primary care, yet few data are available concerning its prevalence, complications, and management in clinical medicine. The following case illustrates the clinical perils of polypharmacy and serves as a point for critical discussion.

METHODS

MEDLINE was searched, using the key word "polypharmacy," from 1994 to the present. A case report of polypharmacy is described, and a novel protocol for the management of polypharmacy is proposed.

RESULTS

Polypharmacy can lead to unnecessary expense, wasted time, and embarrassment on the part of the patient and confusion and mismanagement on the part of the physician. The literature reveals controversy surrounding the definition of polypharmacy and reflects the considerable morbidity and expense associated with polypharmacy. Finally, the SAIL protocol shows that physicians need to keep in mind simplicity, adverse effects, indications, and a precise list of all medications to manage appropriately a patient's drug regimen.

CONCLUSIONS

Polypharmacy is associated with morbidity and iatrogenic complications. The SAIL protocol can be a useful tool in the management of this entity. More research needs to be done on the prevalence, complications, and management of polypharmacy.

Vitamin A, visual pigments, and visual receptors in Drosophila

The fly visual system has served for decades as a model for receptor spectral multiplicity and vitamin A utilization. A diverse armamentarium of structural techniques has dovetailed with convenient electrophysiology, photochemistry, genetics, and molecular biology in Drosophila to facilitate recent progress, which is reviewed here. New data are also presented. Ultrastructure of retinula cells of carotenoid-deprived flies shows that organelles associated with protein biosynthesis, i.e., rough endoplasmic reticulum and Golgi apparatus, are present, while organelles associated with rhabdomere turnover, i.e., multivesicular bodies (MVBs), are rare. Ultrastructure and morphometry suggest that retinoic acid-rearing stimulates membrane export and rhabdomere buildup, even though functional rhodopsin is missing. Confocal microscopy suggests that RH4, one of the ultraviolet rhodopsins, may reside in the previously-described pale fluorescent R7 cells with RH3 in the yellow fluorescent R7 cells.

Hepatic uptake of choline in rat liver basolateral and canalicular membrane vesicle preparations

Choline, an endogenous quaternary ammonium ion, is transported into the liver by both saturable and nonsaturable processes. The objective of the present investigation was to determine the driving force(s) for uptake of choline in rat liver basolateral membrane (blLPM) and canalicular membrane (cLPM) vesicles. Choline is transported into an osmotically sensitive intravesicular space in both blLPM and cLPM. Uptake of [3H]choline into both blLPM and cLPM exhibited temperature dependence (0 degree C vs. 37 degrees C). A valinomycin-induced inside-negative K+ diffusion potential significantly stimulated initial uptake of [3H]choline in both vesicles. Choline uptake in blLPM and cLPM was not stimulated in the presence of an inwardly directed sodium gradient or an outwardly directed H+ gradient, and ATP did not enhance choline uptake in cLPM. Choline itself and structurally similar derivatives, such as hemicholinium-3 and succinylcholine, inhibited [3H]choline uptake 11 to 92% (at 10-fold higher concentrations) in blLPM and cLPM. Other cations, including N1-methylnicotinamide, thiamine and d-tubocurarine, and cardioglycosides did not inhibit choline transport in either vesicle preparation. In addition, [3H]choline uptake into both blLPM and cLPM was enhanced when vesicles were preloaded with nonradiolabeled choline (trans-stimulation). Kinetic studies indicated that choline was transported into blLPM by both saturable and passive processes and into cLPM predominantly by a saturable process. These results suggest that the transport of choline is likely mediated by a potential-sensitive conductive pathway in both blLPM and cLPM. The electrogenic pathway in cLPM may play a role in the reabsorption of choline from bile.

Control of Drosophila opsin gene expression by carotenoids and retinoic acid: northern and western analyses

In the fly, thorough retinoid deprivation is possible, to optimize investigation of the effects of vitamin A metabolites and retinoic acid (RA) on visual development. Retinoids had been found to control fly opsin gene transcription, though this finding was contested. Northern blots on Drosophila heads showed that mRNA of Rh1 (the predominant rhodopsin) was high in vitamin A replete controls, very low in deprived flies, and increased upon feeding carrot juice to deprived flies as early as 1 hr. Expression of the ribosomal protein 49 [rp49] gene (the control) was equal both in deprivation and in replacement. Recovery of Rh1 protein upon such carotenoid replacement followed, barely detectable on Western blots at 4 hr but conspicuous by 8 hr. Alternative chromophore deprivation with yeast-glucose food yielded flies with opsin mRNA on Northerns but not rhodopsin, as demonstrated by Western blots, spectrophotometry and the electroretinogram (ERG). Rh1's mRNA but not Rh1 protein resulted from rearing flies from egg to adult on the otherwise deprivational medium supplemented with RA or beef brain-heart infusion. By comparing results from these different media it was concluded that: [1] deprivation and replacement affect opsin gene transcription; and [2] contradictory conclusions were from chromophore deprivation which does not eliminate all retinoid dependent factors which could affect the opsin promoter. Preliminary evidence shows that carotenoid deprivation decreases two proteins relevant to visual function: [1] phospholipase C (PLC); and [2] Drosophila retinoid binding protein (DRBP).

Visualization of iontophoretic transport paths in cultured and animal skin models

Physiological structures associated with iontophoretic paths in hairless mouse skin and two cultured skin models ("EpiDerm" by Mattek, Corp., and "SKIN2" by Advanced Tissue Sciences, Inc.) are reported. Visualization of ionic paths at current densities between 20 and 100 microA/ cm2 is accomplished by the counterdirectional transport of Fe(CN)6(4-) and Fe3+, resulting in the controlled precipitation of colloidal Prussian blue, Fe4[Fe(CN)6]3, at sites of high ionic conductivity. Examination of the Fe4[Fe(CN)6]3-stained tissues using optical microscopy allows unequivocal assignment of iontophoretic paths to physiological structures in the stratum corneum. Deposition of Fe4[Fe(CN)6]3 occurs exclusively at hair follicles in hairless mouse skin, indicating that these appendages provide highly conductive porous paths during iontophoresis. In contrast, the counterdirectional transport of Fe(CN)6(4-) and Fe3+ across cultured skin models, which lack appendages, results in the deposition of Fe4-[Fe(CN)6]3 along the boundaries of corneocytes. This observation suggests that paracellular iontophoretic transport through lipid bilayer regions is the predominant transport path in the absence of low-resistance pores.

Comparison of eight microcomputer dietary analysis programs with the USDA Nutrient Data Base for Standard Reference

OBJECTIVE

To compare the general operating features and nutrient databases of eight microcomputer dietary analysis programs.

DESIGN

A 3-day food record with 73 food items was entered into each program by the authors. The general operating features of the program were summarized and evaluated. The nutrient database was evaluated by comparing the nutrient analysis output with the 1993 US Department of Agriculture (USDA) Nutrient Data Base for Standard Reference (NDB), full version, release 10, for microcomputers.

RESULTS

The programs varied in cost, number of foods and nutrients in the database, use of non-USDA data, and inputting of data for missing values. We also found differences in the quality of user manuals and help screens, ease of food entry and averaging of 3-day nutrient intake, speed of analyzing and printing results, quality and number of print/export options, and overall ease of learning and using the program. All but one of the programs were within 15% of the USDA NDB for energy, protein, total fat, and total carbohydrates. However, there was some difference in the number of other nutrients and food components varying more than 15% from the USDA NDB. These differences occurred because of variations in the number of food items included in each programs' database and the number of missing nutrient values in the database.

APPLICATIONS

Our results demonstrate the importance of carefully choosing a microcomputer dietary analysis program that is suitable to the user's specific and predetermined needs.

In vitro metabolism of terfenadine by a purified recombinant fusion protein containing cytochrome P4503A4 and NADPH-P450 reductase. Comparison to human liver microsomes and precision-cut liver tissue slices

The metabolism of terfenadine was studied with a cDNA-expressed/purified recombinant fusion protein containing human liver microsomal cytochrome P4503A4 (CYP3A4) linked to rat NADPH-P450 reductase (rF450[mHum3A4/mRatOR]L1) and was compared with that observed in the presence of human liver microsomes and precision-cut human liver tissue slices. In all three cases, [3H]terfenadine was metabolized to at least three major metabolites. LC/MS (electrospray) analysis confirmed that these metabolites were alpha, alpha-diphenyl-4-piperidinomethanol (M5), t-butyl hydroxy terfenadine (M4), and t-butyl carboxy terfenadine (M3), although the level of M5 detected in the presence of fusion protein was greater than that found with microsomes or tissue slices. Two additional metabolites, M1 (microsomes and tissue slices) and M2 (fusion protein), were also detected, but remain uncharacterized. Consumption of parent drug (microsomes: KM = 9.58 +/- 2.79 microM, Vmax = 801 +/- 78.3 pmol/min/nmol CYP; fusion protein: KM = 14.1 +/- 1.13 microM, Vmax = 1670 +/- 170 pmol/min/nmol CYP) and t-butyl hydroxylation to M4 (microsomes: KM = 12.9 +/-3.74 microM, Vmax = 643 +/- 62.5 pmol/min/nmol CYP, ; fusion protein: KM = 30.0 +/- 2.55 microM, Vmax = 1050 +/- 141 pmol/min/nmol CYP) obeyed Michaelis-Menten kinetics over the terfenadine concentration range of 1-200 microM. Ketoconazole, a well-documented CYP3A inhibitor, effectively inhibited terfenadine metabolism in all three models. The conversion of M4 to M3, studied with human liver microsomes and fusion protein, was NADPH-dependent and inhibited by ketoconazole. It is concluded that cDNA-expressed CYP3A4, in the form of a NADPH-P450 reductase-linked fusion protein, may also serve as a model for studying the metabolism of terfenadine in vitro and many other drugs.

Disaggregation in population forecasting: do we need it? And how to do it simply

"We have described a method for reducing the dimensionality of the forecasting problem by parsimoniously modeling the evolution over time of the age schedules of vital rates. This method steers a middle course between forecasting aggregates and forecasting individual age specific rates: we reduce the problem to forecasting a single parameter for fertility and another one for mortality. We have described a number of refinements and extensions of those basic methods, which preserve their underlying structure and simplicity. In particular, we show how one can fit the model more simply, incorporate lower bounds to the forecasts of rates, disaggregate by sex or race, and prepare integrated forecasts of rates for a collection of regions. We also discuss alternate approaches to forecasting the estimated indices of fertility and mortality, including state-space methods. These many versions of the basic method have yielded remarkably similar results." (SUMMARY IN FRE)

Stochastic population forecasts for the United States: beyond high, medium, and low

"This article presents and implements a new method for making stochastic population forecasts that provide consistent probability intervals. We blend mathematical demography and statistical time series methods to estimate stochastic models of fertility and mortality based on U.S. data back to 1900 and then use the theory of random-matrix products to forecast various demographic measures and their associated probability intervals to the year 2065. Our expected total population sizes agree quite closely with the Census medium projections, and our 95 percent probability intervals are close to the Census high and low scenarios. But Census intervals in 2065 for ages 65+ are nearly three times as broad as ours, and for 85+ are nearly twice as broad. In contrast, our intervals for the total dependency and youth dependency ratios are more than twice as broad as theirs, and our ratio for the elderly dependency ratio is 12 times as great as theirs. These items have major implications for policy, and these contrasting indications of uncertainty clearly show the limitations of the conventional scenario-based methods."

[Modeling and projecting mortality in Chile]

"In a recent paper, Lee and Carter developed a new method for analyzing and forecasting time series of age specific mortality, and applied it to the U.S. population. In this paper, we extend that method to deal with various problems of incomplete data common in Third World populations, and then apply the method to forecast mortality in Chile." (SUMMARY IN ENG)

Fertility decline in Prussia: estimating influences on supply, demand, and degree of control

Change in marital fertility in 407 Prussian Kreise from 1875 to 1910 is modeled to depend on the gap between the number of desired surviving births, N*, divided by child survival, s, and the number that would be born under natural marital fertility, M, given the age at marriage. Some fraction of this gap is averted, depending on the propensity to avert unwanted births, D. Although none of these components is observed directly, we can estimate each indirectly under strong assumptions. Decline in N*/s accounts for twice as much of the decline in fertility as does an increase in D. Natural fertility rose during the period. Unwanted births increased slightly, despite a tripling of births averted. The most important causes of decline in N* were increases in female labor supply, real income, and health workers. A rising level of education is the most important cause of increasing propensity to avert births. Demand-side changes were important causes of the transition, but changes in readiness to contracept also were important, as was the interaction of the two.

Famine, revolt, and the dynastic cycle: population dynamics in historic China

"Historians have long noticed that population declines in ancient China often coincided with dynasty changes, and that most of these declines were the result of internecine wars which, in turn, were often initiated by famine or density pressure. Since the interactions between density pressure, internecine wars, and dynasty changes cannot be explained by the traditional age-specific density-dependent population structure, we propose to use a bandit/peasant/ruler occupation-specific population model to interpret the dynamic socio-economic transitions of ancient Chinese population, and provide econometric support to our model. We also highlight the rich dynamics of the composition of human population, a factor which was often neglected in previous research on general populations."

Visual laser ablation of the prostate: clinical experience in 108 patients

Visual laser ablation of the prostate was performed on 108 patients (ages 44 to 84 years) as an outpatient procedure from May 1992 to October 1992. Preoperatively, the patients underwent digital rectal examinations, determination of prostate specific antigen levels and transrectal ultrasound guided biopsies when necessary to rule out the presence of prostate cancer. The Urolase laser fiber delivery system was used to transmit laser energy from a neodymium: YAG generator. For the 97 patients with preoperative and postoperative American Urological Association symptom index testing, scores decreased by an average of 12.59 (p < 0.001). For the 75 patients with preoperative and postoperative uroflow rates an average increase of 4.92 ml. per second (p < 0.001) was noted following the procedure. Only 3 patients required hospitalization for an average of 1.33 days. No patient required a blood transfusion. There have been no fluid or electrolyte abnormalities following visual laser ablation of the prostate. There have been no recognizable urethral strictures, deaths or postoperative sepsis. Only 3 patients experienced retrograde ejaculation. We found visual laser ablation of the prostate to be a cost-effective and less morbid alternative to traditional transurethral resection of the prostate.

Modeling and forecasting U.S. sex differentials in mortality

"This paper examines differentials in observed and forecasted sex-specific life expectancies and longevity in the United States from 1900 to 2065. Mortality models are developed and used to generate long-run forecasts, with confidence intervals that extend recent work by Lee and Carter (1992). These results are compared for forecast accuracy with univariate naive forecasts of life expectancies and those prepared by the Actuary of the Social Security Administration."

Stochastic demographic forecasting

"This paper describes a particular approach to stochastic population forecasting, which is implemented for the U.S.A. through 2065. Statistical time series methods are combined with demographic models to produce plausible long run forecasts of vital rates, with probability distributions. The resulting mortality forecasts imply gains in future life expectancy that are roughly twice as large as those forecast by the Office of the Social Security Actuary.... Resulting stochastic forecasts of the elderly population, elderly dependency ratios, and payroll tax rates for health, education and pensions are presented."

Comparison of six microcomputer dietary analysis systems with the USDA Nutrient Data Base for Standard Reference

We compared the general operating features and nutrient databases of six microcomputer dietary analysis systems. A 3-day food record with 73 food items was entered into each program; nutrient averages were compared with the US Department of Agriculture Nutrient Data Base for Standard Reference (USDA NDB), full version, release 9, for microcomputers. The six programs were found to vary widely in cost, number of foods and nutrients in the database, use of non-USDA data and imputation of data for missing values, number of print/export options, time to analyze the 3-day food record, and overall ease of use. Although all of the microcomputer dietary analysis systems were within 7% of the USDA NDB for energy, protein, total fat, and total carbohydrates, the proportion of other nutrients varying more than 15% from the USDA NDB varied considerably between programs. Variance among programs for 3-day food record nutrient values occurred because of differences in the number of food items included in the database (leading to varying degrees of substitution), the recency of the nutrient data (whether or not the most recent USDA releases had been incorporated), and the number of missing values (the degree to which non-USDA sources or estimated calculations were used to fill in the blanks from the USDA standard). Our results demonstrate that it is important for each dietitian to carefully choose a microcomputer dietary analysis system that is suitable to specific and predetermined needs.

Submucosal ureteral calculi: a new entity?

We describe 3 patients with ureteral calculi who failed multiple extracorporeal shock wave lithotripsy treatments and whose stones could not be visualized by ureteroscopy despite radiological confirmation. We contend that these ureteral stones migrated submucosally and are refractory to the aforementioned treatment modalities. Each patient had a common presenting complaint of intermittent flank pain 5 years in duration, leading us to believe that long-standing stone impaction is a prerequisite for this entity. Our experience is reviewed.

Stereoselective synthesis of the diunsaturated metabolites of valproic acid

Two diene metabolites of valproic acid (VPA), (E)-2-n-propyl-2,4-pentadienoic acid and (E)-2-(1'-propenyl)-(E)-2-pentenoic acid, were stereoselectively synthesized. Mesylate elimination in the final step to produce the unsaturation at position 2 was stereospecific for the (E)-configuration in the case of 2. Gas chromatography-mass spectroscopy and NMR were used to confirm the configuration of each diene including the minor isomers, (Z)-2-n-propyl-2,4-pentadienoic acid and (Z)-2-(1'-propenyl)-(E)-2-pentenoic acid. Analysis of the dienes, as PFB derivatives by negative chemical ionization GC-MS from a serum extract of a patient on VPA therapy, revealed the presence of four peaks that in order of elution correspond to 9, 18, 1, and 2.

U.S. births and limit cycle models

Lee's (1974) formal demographic feedback models summarize the implications for births and age-structure of neo-Malthusian theories of baby booms such as those of Easterlin. For some parameter values, such models imply sustained cycles, so-called "limit cycles", in births. Frauenthal and Swick recently reestimated a continuous-age version of Lee's basic cohort model with U.S. series and, contrary to Lee's original findings, concluded that "limit cycles oscillations have been occurring in U.S. births." This article disputes their conclusion, ascribing it to an inconsistency in detrending procedures. Furthermore, it corrects Lee's original conclusion by showing that his alternative period labor-force feedback model, estimated from U.S. series, leads to cycles of implausibly long period. This article thus reopens the question of whether any feedback model could account for the observed cycles in U.S. births.

Induced population growth and induced technological progress: their interaction in the accelerating stage

"A simple model of Malthusian population growth combined with population-induced technological progress generates accelerating growth. The model may be relevant for a first stage of growth in which natural resource limitations can be overcome through technological progress; it is not applicable to a later stage in which resource constraints are more resistant. Parameter values are roughly inferred from historical experience." (SUMMARY IN FRE)

Population dynamics of humans and other animals

Human population dynamics, at least until the past century, have probably been governed by homeostasis and in this resembled those of other animals. Because human population homeostasis was probably substantially weaker than among large mammals, its operation has been less obvious. Nonetheless, the empirical evidence for advanced agriculturalists is compelling. Unlike animals, the human population has tended toward equilibria that have been tending upward at an accelerating rate. The acceleration might reflect long-run positive feedback between density and technological progress, as Boserup has suggested. Because homeostasis was weak, its role in shorter run historical explantation is limited; its force was gentle and easily overwhelmed by other particular influences. Malthusian oscillation, in the sense of distinctive medium-run dynamics arising from homeostasis, probably did not occur. And because homeostasis was weak, density dependence can in principle explain only a minute proportion of the annual variation in population growth rates. Yet homeostasis plays an essential role in demographic theory. Without it, we are incapable of explaining population size and change over time except by recounting a mindless chronology of events back to the beginning of humanity--whenever that was. Without it, we cannot explain the response of population growth to economic growth. Without it, we cannot explain recovery from catastrophe or the rapid natural increase in many frontier regions. Without it, we cannot properly analyze the influence of climatic variation and other partially density-independent factors. Our basic understanding of human history requires a grasp of what homeostasis can explain and what it cannot. A homeostatic approach to population dynamics also leads to questions about the roles of reproductive norms and institutions, not just whether they encourage high or low fertility, but whether they make natural increase responsive to resource abundance. And if they do, whether they strike the balance of population and the means of subsistence at a relatively prosperous or impoverished level. Such considerations may contribute to an understanding of broad preindustrial differences among the regions of the world in densities, average levels of vital rates, and living standards--which was very much how Malthus viewed the matter. Ordinary homeostatic tendencies essentially vanish in the course of economic development, and they were probably all but gone from much of Europe by the end of the 19th century.(ABSTRACT TRUNCATED AT 400 WORDS)

Scrotal fat necrosis

A case of scrotal fat necrosis is presented. The clinical presentation usually is characteristic and the condition can be managed nonoperatively.

Necrobiotic xanthogranuloma of the eyelid

Necrobiotic xanthogranuloma with paraproteinemia is characterized by multiple nodules or plaques that involve the periorbital area along with other parts of the body. A dysproteinemia due to an IgG paraprotein is associated with the condition; low serum complement, cryoglobulinemia, leukopenia, and hyperlipemia are also sometimes seen. Multiple myeloma is present in some cases. Two cases of necrobiotic xanthogranuloma with IgG monoclonal gammopathy were seen. Both initially had ocular symptoms and in the second case, the ocular manifestations have dominated the clinical picture. Histologically, these granulomas are characterized by collagen necrobiosis and by the presence of many foamy histiocytes and Touton giant cells. Because necrobiotic xanthogranuloma with monoclonal gammopathy frequently has prominent manifestations in the orbital region, may result in dysfunction of the eyelids or extraocular muscles, and is associated with potentially life-threatening systemic conditions, its recognition by the ophthalmologist is important.

Laser surgery in the medically compromised patient

Dermatology has entered a new dimension with the introduction of the laser. There are expanding clinical indications for laser excision. The CO2 laser in the cutting mode can incise tissue as sharply as finely honed steel, yet its photocoagulative properties allow rapid sealing of blood vessels and lymphatics. The physician can thereby perform in a relatively bloodless surgical field. Minimal adjacent normal tissue is injured, there is less local postoperative edema, and fewer postoperative analgesics are required. Since there is no need to use epinephrine as a local vasoconstrictive agent and there is no need to use electrocoagulation for control of hemorrhage, CO2 laser excision presents less risk to the medically compromised patient. The CO2 laser may also diminish the risk of seeding or spreading neoplastic cells in the perioperative field.

Target fertility, contraception, and aggregate rates: toward a formal synthesis

This paper develops a stock adjustment model relating total expected births to conventional aggregate fertility rated for married women over 25. Each year, cohorts bear about 20 percent of their additional expected births. Aggregate U.S. rates have been consistent with expectations as expressed in surveys between 1955 and 1975; indeed, total expected births may be inferred from aggregate fertility behavior. A peculiar empirical finding is that the additional expected fertility of nonterminators has not changed since 1955, despite the dramatic decline in total expected and actual fertility. The model leads to a dynamic expression for the duration pattern of current and cumulative fertility and for the proportion of couples who have terminated childbearing. The model is also used to analyze the effects of changing contraceptive failure rates on fertility patterns. For example, a decline in "timing" failure rates increases duration-specific fertility five years later.

Effect of probenecid on penetration of oxacillin into fibrin clots in vitro

Probenecid significantly enhanced the in vitro penetration of oxacillin into fibrin clots suspended in rabbit serum or normal saline.