Long-term therapy of chronic delta hepatitis with peginterferon alfa.

BACKGROUND: Chronic delta hepatitis virus (HDV) infection rapidly progresses to cirrhosis. Treatment with peginterferon for up to 2 years is often without durable response. AIM: To examine the efficacy and safety of long-term peginterferon in achieving a durable response. METHODS: Treatment was initiated with 180 µg/week of peginterferon alfa-2a with titration to a maximal tolerable dose, for up to 5 years. Liver biopsies and hepatic venous pressure gradients (HVPG) were evaluated at baseline, 1, 3 and 5 years. The primary endpoint was histological improvement or loss of serum HDV and HBsAg at 3 years. RESULTS: Thirteen patients were treated for a median of 140 weeks (6-260) with an average peginterferon dose of 180 µg/week (90-270). At baseline, most had advanced disease (median Ishak fibrosis = 3) with portal hypertension (HVPG = 10.2 ± 6 mmHg). Five of 13 patients (39%) achieved the primary endpoint, with three seroconverting for HBsAg after 24, 37 and 202 weeks of treatment. Histological inflammation improved after 1 year, (median HAI: 10 vs. 7, P = 0.01) with persistence in 4/5 patients at 3 years (median HAI: 7.5). Greatest improvements occurred in the first year. Baseline bilirubin and HBsAg levels were significantly lower in virological responders than nonresponders. After 12 weeks, virological responders had a significant decline in HBsAg (1.5 log10 IU/mL, P = 0.05). CONCLUSION: Despite increased doses and duration of therapy, treatment of chronic HDV with peginterferon remains unsatisfactory. Quantitative measures of HBsAg may be an important biomarker of early response to peginterferon therapy in chronic delta hepatitis virus infection.

The natural history of acute hepatitis C: clinical presentation, laboratory findings and treatment outcomes.

BACKGROUND: Acute hepatitis C has variable modes of presentation and frequently results in chronic infection. Its optimal management has yet to be defined. AIM: To establish natural history and complications of treatment of acute hepatitis C. METHODS: Data from all patients presenting with acute hepatitis C to the National Institutes of Health between 1994 and 2007 were reviewed. RESULTS: Twenty-five patients were identified. Symptoms were reported by 80% and jaundice by 40%. Aminotransferase levels and hepatitis C virus (HCV) RNA levels fluctuated greatly; 18% of patients were intermittently negative for HCV RNA. Five patients recovered spontaneously whereas 20 developed chronicity or received interferon-based therapy during the acute phase. Among 15 patients treated during the acute phase with peginterferon with or without ribavirin for 24 weeks, all became HCV RNA negative within 4-8 weeks, and all except two (HIV-positive) achieved a sustained virological response. Side effects (particularly psychiatric) were common and limited treatment in 30%. CONCLUSIONS: Among 25 patients with acute HCV infection, fluctuating illness was common and spontaneous recovery occurred in only 20%. Anti-viral treatment with a 24-week course of peginterferon and ribavirin was highly effective, but marked by frequent and severe side effects.

The art and practice of systems biology in medicine: mapping patterns of relationships.

Systems biology has developed in recent years from a technology-driven enterprise to a new strategic tool in Life Sciences, particularly for innovative drug discovery and drug development. Combining the ultimate in systems phenotyping with in-depth investigations of biomolecular mechanisms will enable a revolution in our understanding of disease pathology and will advance translational medicine, combination therapies, integrative medicine, and personalized medicine. A prerequisite for deriving the benefits of such a systems approach is a reliable and well-validated bioanalytical platform across complementary measurement modalities, especially transcriptomics, proteomics, and metabolomics, that operates in concert with a megavariate integrative biostatistical/bioinformatics platform. The applicable bioanalytical methodologies must undergo an intense development trajectory to reach an optimal level of reliable performance and quantitative reproducibility in daily practice. Moreover, to generate such enabling systems information, it is essential to design experiments based on an understanding of the complexity and statistical characteristics of the large data sets created. Novel insights into biology and system science can be obtained by evaluating the molecular connectivity within a system through correlation networks, by monitoring the dynamics of a system, or by measuring the system responses to perturbations such as drug administration or challenge tests. In addition, cross-compartment communication and control/feed-back mechanisms can be studied via correlation network analyses. All these data analyses depend critically upon the generation of high-quality bioanalytical platform data sets. The emphasis of this paper is on the characteristics of a bioanalytical platform that we have developed to generate such data sets. The broad applicability of Systems Biology in pharmaceutical research and development is discussed with examples in disease biomarker research, in pharmacology using system response monitoring, and in cross-compartment system toxicology assessment.

Solution-phase, parallel synthesis and pharmacological evaluation of acylguanidine derivatives as potential sodium channel blockers.

Solution-phase synthesis of various acylguanidine derivatives and the evaluation of a small library of compounds as potential sodium channel blockers are described.

Identification and characterization of a potential ischemia-selective N-methyl-D-aspartate (NMDA) receptor ion-channel blocker, CNS 5788.

The identification and characterization of a potentially ischemia-selective and orally-active sulfoxide based NMDA ion-channel blocker showing good neuroprotective activity, (R)-(+)-N-(2-chloro-5-methylthiophenyl)-N'-(3-methylsulfinylphenyl)-N'-methylguanidine (CNS 5788), is described.

Malnutrition: trials and triumphs.

Severe malnutrition is uncommon but often fatal, particularly in very young infants or when oedema is present. Another major contributor to mortality is undiagnosed infection. Three pilot studies have recently been performed in severely malnourished patients in therapeutic feeding centres in sub-Saharan Africa. In each, a practical management problem was addressed and a potential solution tested. Three conclusions were reached: young breastfeeding infants were best managed using a supplemented suckling technique; routine antibiotics from admission reduced mortality; and in adults with oedematous malnutrition, therapeutic diets with a lower-than-usual protein:energy ratio were effective in reducing mortality and permitting catch-up weight gain.

Design, synthesis, and pharmacological evaluation of conformationally constrained analogues of N,N'-diaryl- and N-aryl-N-aralkylguanidines as potent inhibitors of neuronal Na+ channels.

In the present investigation, the rationale for the design, synthesis, and biological evaluation of potent inhibitors of neuronal Na+ channels is described. N,N'-diaryl- and N-aryl-N-aralkylguanidine templates were locked in conformations mimicking the permissible conformations of the flexible diarylguanidinium ion (AS+, AA+, SS+). The resulting set of constrained guanidines termed "lockamers" (cyclophane, quinazoline, aminopyrimidazolines, aminoimidazolines, azocino- and tetrahydroquinolinocarboximidamides) was examined for neuronal Na+ channel blockade properties. Inhibition of [14C]guanidinium ion influx in CHO cells expressing type IIA Na+ channels showed that the aminopyrimidazoline 9b and aminoimidazoline 9d, compounds proposed to lock the N,N'-diarylguanidinium in an SS+ conformation, were the most potent Na+ channel blockers with IC50's of 0.06 microM, a value 17 times lower than that of the parent flexible compound 18d. The rest of the restricted analogues with 4-p-alkyl substituents retained potency with IC50 values ranging between 0.46 and 2.9 microM. Evaluation in a synaptosomal 45Ca2+ influx assay showed that 9b did not exhibit high selectivity for neuronal Na+ vs Ca2+ channels. The retention of significant neuronal Na+ blockade in all types of semirigid conformers gives evidence for a multiple mode of binding in this class of compounds and can possibly be attributed to a poor structural specificity of the site(s) of action. Compound 9b was also found to be the most active compound in vivo based on the high level of inhibition of seizures exhibited in the DBA/2 mouse model. The pKa value of 9b indicates that 9b binds to the channel in its protonated form, and log D vs pH measurements suggest that ion-pair partitioning contributes to membrane transport. This compound stands out as an interesting lead for further development of neurotherapeutic agents.

In vitro neuroprotection by substituted guanidines with varying affinities for the N-methyl-D-aspartate receptor ionophore and for sigma sites.

Radioligand binding techniques were used to determine the affinity of a series of substituted guanidine derivatives for 1) the binding site within the ion channel of the N-methyl-D-aspartate (NMDA) receptor, as defined by displacement of MK-801 ([3H]dizocilpine) and 2) sigma sites as defined by displacement of [3H]N,N'-di-(o-tolyl)guanidine. The goal was to find ligands with high affinity and selectivity for the NMDA receptor ion-channel site. The neuroprotective activity of these compounds was assessed by their ability to protect cortical neurons from injury caused by a 5-min exposure to 500 microM glutamate in vitro. Release of lactate dehydrogenase into the culture medium by damaged neurons was used as an index of neuronal injury. The 14 compounds tested had IC50 values ranging from 37.3 nM to 12.7 microM for the NMDA receptor ion-channel site and from 8.3 nM to 7.25 microM for sigma sites. Affinity for the ion-channel site was improved by unsymmetrical substitutions on the guanidine moiety. All compounds in the series protected cortical neurons against glutamate toxicity, with EC50 values (concentration affording 50% protection) ranging from 0.38 to 28.25 microM. The neuroprotective effect of each compound was positively correlated with its ion-channel site affinity (r = 0.94); no correlation between neuroprotective efficacy and sigma site binding affinity was found (r V -0.13) establishing clearly that neuroprotection in this assay was linked to NMDA antagonist properties.

Synthesis and structure-activity studies of N,N'-diarylguanidine derivatives. N-(1-naphthyl)-N'-(3-ethylphenyl)-N'-methylguanidine: a new, selective noncompetitive NMDA receptor antagonist.

Diarylguanidines, acting as NMDA receptor ion channel site ligands, represent a new class of potential neuroprotective drugs. Several diarylguanidines structurally related to N,N'-di-o-tolylguanidine (DTG), a known selective sigma receptor ligand, were synthesized and evaluated in in vitro radioligand displacement assays, with rat or guinea pig brain membrane homogenates, using the NMDA receptor ion channel site specific radioligand [3H]-(+)-5(S)-methyl-10(R),11-dihydro-5H-dibenzo[a,d]cyclohepten-5 ,10- imine (MK-801, 3), and the sigma receptor-specific radioligand [3H]-di-o-tolylguanidine (DTG, 5). This paper presents the structure-activity relationships leading to novel tri- and tetrasubstituted guanidines, which exhibit high selectivity for NMDA receptor ion channel sites and weak or negligible affinity for sigma receptors. The in vitro binding results from symmetrically substituted diphenylguanidines indicated that compounds having ortho or meta substituents (with respect to the position of the guanidine nitrogen) on the phenyl rings showed greater affinity for the NMDA receptor ion channel site compared with para-substituted derivatives. Among the group of ring substituents studied for symmetrical diarylguanidines, an isopropyl group was preferred at the ortho position and an ethyl group was preferred at the meta position. Several unsymmetrical guanidines containing a naphthalene ring on one nitrogen atom and an ortho- or a meta-substituted phenyl ring on the second nitrogen atom, e.g., N-1-naphthyl-N'-(3-ethylphenyl)guanidine (36), showed a 3-5-fold increase in affinity for the NMDA receptor ion channel site and no change in sigma receptor affinity compared to the respective symmetrical counterparts. Additional small substituents on the guanidine nitrogen atoms bearing the aryl rings resulted in tri- and tetrasubstituted guanidine derivatives which retained affinity for NMDA receptor ion channel sites but exhibited a significant reduction in their affinities for sigma receptors. For example, N-1-naphthyl-N'-(3-ethylphenyl)-N'-methylguanidine (40) showed high affinity for the NMDA receptor ion channel site (IC50 = 36 nM vs [3H]-3) and low affinity for sigma receptors (IC50 = 2540 nM vs [3H]-5). Selectivity for the NMDA receptor ion channel sites over sigma receptors appears to be dependent upon the structure of the additional substituents on the guanidine nitrogen atoms bearing the aryl groups. Methyl and ethyl substituents are most preferred in the tri- and tetrasubstituted diarylguanidines. The trisubstituted guanidine, N-1-naphthyl-N'-(3-ethylphenyl)-N'-methylguanidine (40) and its close analogues showed good in vivo neuroprotection and are potential neuroprotective drug candidates for the treatment of stroke and other neurodegenerative disorders.

An approach to the creation of multimedia textbooks for radiology instruction.

We developed a standardized approach for creating computerized multimedia textbooks based on four principles: (1) multimedia textbooks should resemble printed books, (2) the creation of multimedia textbooks should be relatively inexpensive, (3) multimedia textbooks should be completely digital, and (4) the construction of multimedia textbooks should be simple. To facilitate this approach, an inexpensive, user-friendly multimedia authoring tool called The Annotator was used. The Annotator, a Hypercard-based program that runs on any Macintosh computer, helps authors rapidly create sophisticated radiologic multimedia textbooks. This program provides a textbooklike shell that can be filled with digitized media (video clips, audio clips, images, and text). This approach, which is applicable to any multimedia hardware platform, allows the authorship of multimedia textbooks that can be easily transported to any future multimedia platform.

The instructional effectiveness of a radiology multimedia textbook (HyperLung) versus a standard lecture.

RATIONALE AND OBJECTIVES: Information overload is a significant problem for the modern radiologist. This prospective study compares the instructional effectiveness of a multimedia textbook (HyperLung) with a lecture. HyperLung is a radiologic multimedia textbook about imaging diffuse lung disease created using a multimedia authoring tool, the Annotator (the University of Iowa Second Look Computing, Iowa City, IA), on the Apple Macintosh computer (Apple Computer, Cupertino, CA). METHODS: Forty-nine staff physicians and residents in the Department of Radiology were randomized to receive instruction either by HyperLung or by a lecture. The instructional content was the same in both groups, and both groups were tested before and after instruction. The actual time spent in each instructional situation was recorded. RESULTS: The instructional effectiveness of the multimedia textbook and lecture was equal. The instructional efficiency of HyperLung was only 60% of the lecture. Users of the multimedia textbook found it enjoyable and straightforward to use. CONCLUSIONS: Multimedia textbooks have a promising future in radiology education.

10,5-(Iminomethano)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene and derivatives. Potent PCP receptor ligands.

IDDC (3, 10,5-(iminomethano)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene++ +) and a series of substituted derivatives were synthesized and evaluated in vitro for their ability to displace tritiated MK-801 ([3H]-2) from its specific binding site in guinea pig brain homogenate. Substitution at the 3-position of 3 with bromine, chlorine, and fluorine led to increased binding affinity. In contrast, substitution of donor groups at the 3-position gave decreased binding affinities, as did all substitutions at the 7-position and on nitrogen. Where racemic mixtures were resolved, the (+)-optical antipodes were more active than their enantiomers or racemates. The most active ligand found in this study was (+)-13e (IC50 = 15.5 +/- 4.5 nM). The affinity of (+)-13e for the PCP receptor makes it among the most potent ligands known. In vitro neuroprotection was demonstrated by 3, (+)-3, and (+)-6 (N-Me-IDDC) against glutamate-induced cell death in rat hippocampal cells.

Effects of a novel NMDA antagonist on experimental stroke rapidly and quantitatively assessed by diffusion-weighted MRI.

We employed diffusion-weighted MRI (DWI) to identify regions of focal brain ischemia during the first 3 hours after permanent occlusion of the middle cerebral artery in rats. Using DWI as early as 30 minutes after the onset of ischemia, it was possible to identify the areas of brain destined to progress to infarction over the next 24 hours in untreated animals, as demonstrated by postmortem evaluation. DWI studies revealed the cerebroprotective effects of a noncompetitive N-methyl-D-aspartate receptor antagonist, CNS 1102, administered 15 minutes postocclusion, both on the cortical and caudoputaminal regions during the initial 3 hours of ischemia. Although the treatment effect lessened over the next 21 hours in a few animals with lower plasma drug levels at 3 hours, postmortem studies demonstrated a 66% reduction in the total volume of infarcted tissue with the treatment and confirmed the DWI results. T2-weighted MRI obtained at similar times revealed little or no abnormality. These results suggest that DWI provides a sensitive in vivo measure of focal cerebral ischemic injury and can assess the beneficial effects of cytoprotective therapy. DWI may be useful in the early evaluation of human stroke patients and in monitoring the effects of cerebroprotective therapies in the clinical setting.

New CNS-specific calcium antagonists.

Ischemic insults to the brain in stroke or traumatic brain injury produce excessive release of glutamate from depolarized nerve terminals. This excessive glutamate release in turn stimulates massive calcium entry into nerve cells, activating a biochemical cascade that results in cell death. A major pathway of calcium entry into depolarized nerve cells is through voltage-sensitive, high threshold calcium channels. A large fraction of this calcium entry is mediated through "R-type" calcium channels, channels resistant to blockage by dihydropyridine calcium antagonists such as nimodipine. A newly discovered compound derived from spider venom, CNS 2103, antagonizes both R-type channels and dihydropyridine-sensitive ("L-type") calcium channels. This broad spectrum of action, coupled with selectivity for calcium channels over other classes of voltage-sensitive and ligand-gated ion channels, makes CNS 2103 an interesting lead for development of drugs to treat ischemic brain injury. Activation of presynaptic ("N-type") calcium channels in nerve terminals is a primary cause of excessive neurotransmitter release in brain ischemia. Prevention of glutamate release by blockade of N-type channels in glutamatergic nerve terminals may, at an early stage in the pathophysiological cascade, abort the process leading to nerve cell death. Cambridge NeuroScience has developed a novel rapid kinetic approach for monitoring glutamate release from brain nerve terminals in vitro, and this has led to CNS 1145, a substituted guanidine that selectively blocks a kinetic component of calcium-dependent glutamate release mediated by persistent depolarization. Additional evidence suggests that CNS 1145 antagonizes presynaptic N-type calcium channels, and this may account at least in part for its ability to block glutamate release.

Ruptured hepatic adenoma. A spectrum of presentation and treatment.

Six cases of ruptured hepatic adenoma treated in our medical center were reviewed with attention directed toward presenting symptomatology and methods of treatment. These patients, five women who were long-term users of oral contraceptives and one man who had never taken steroid medication, presented with right upper quadrant abdominal pain of variable degree and duration. The cardiovascular status of these patients was also variable, ranging from a normal blood pressure, which allowed an orderly workup, and planned resection of the tumor to hypovolemic shock requiring emergency laparotomy for control of hemorrhage. The extent of surgery depended on the location and the number of adenomas, with the goal being to resect the adenoma and control hemorrhage while preserving as much normal liver parenchyma as possible. The treatment of choice in this disease is resection of the tumor with a margin of normal liver parenchyma. In those cases in which that is not practical, resectional debridement has proven to be an effective alternative.

Synthesis and characterization of a series of diarylguanidines that are noncompetitive N-methyl-D-aspartate receptor antagonists with neuroprotective properties.

Four diarylguanidine derivatives were synthesized. These compounds were found to displace, at submicromolar concentrations, 3H-labeled 1-[1-(2-thienyl)cyclohexyl]piperidine and (+)-[3H]MK-801 from phencyclidine receptors in brain membrane preparations. In electrophysiological experiments the diarylguanidines blocked N-methyl-D-aspartate (NMDA)-activated ion channels. These diarylguanidines also protected rat hippocampal neurons in vitro from glutamate-induced cell death. Our results show that some diarylguanidines are noncompetitive antagonists of NMDA receptor-mediated responses and have the neuroprotective property that is commonly associated with blockers of the NMDA receptor-gated cation channel. Diarylguanidines are structurally unrelated to known blockers of NMDA channels and, therefore, represent a new compound series for the development of neuroprotective agents with therapeutic value in patients suffering from stroke, from brain or spinal cord trauma, from hypoglycemia, and possibly from brain ischemia due to heart attack.

Conductance states activated by glycine and GABA in rat cultured spinal neurones.

The conductance properties of single Cl- channels activated by glycine and gamma-aminobutyric acid (GABA) were examined in rat spinal cord neurones grown in cell culture. The majority (85%) of spinal neurones were sensitive to both glycine and GABA as were most (83%) outside-out patches tested. Glycine and GABA activated multiple conductance state Cl- channels with linear current-voltage properties when the chloride activities of the solutions bathing both sides of the membrane were similar. Glycine activated six distinct conductance states with conductances of 14, 20, 30, 43, 64 and 93 pS, whereas GABA activated five states with conductances of 13, 20, 29, 39 and 71 pS. The 30 and 43 pS states and the 20 and 29 pS states were observed most frequently with glycine and GABA, respectively. As the values of the glycine- and GABA-activated conductance states form a geometric progression when arranged in ascending order, we concluded that the channels do not consist of a cluster of identical pores. Additional conductance states (50 and 100 pS) were activated by glycine occasionally. The similarity between the conductances of the states activated by the two transmitters is consistent with the proposal that they both activate the same type of Cl- channel.