A general synthetic approach for obtaining cationic and anionic inorganic nanoparticles via encapsulation in amphiphilic copolymers.

A series of amphiphilic copolymers with variable charge densities on their backbone is synthesized. Positively charged N,N,N-trimethylammonium-2-ethyl methacrylate iodide or negatively charged 2-(methacryloyloxy)ethylphosphonic acid and lauryl methacrylate are used as building blocks. When wrapped around hydrophobically capped inorganic nanoparticles (NPs), the latter are able to disperse in aqueous solutions. Using this method, positively as well as negatively charged colloidal NPs can be synthesized in a reliable way. The method presented herein allows the charge on the NPs to be adjusted to different negative and positive values by using polymers with a variable ratio of charged monomers and lauryl methacrylate. Virtually all kinds of hydrophobic inorganic NPs could be coated with these amphiphilic polymers. The coating procedure is demonstrated for Au particles as well as for CdSe/ZnS quantum dots. To date, wrapping amphiphilic polymers around NPs has led only to anionic NPs. The polymers synthesized in this work allow for positively charged NPs with a high colloidal stability.

Differential expression of alternative Acyl-CoA binding protein (ACBP) transcripts in an inducible human preadipocyte cell line.

Understanding the function of fat metabolism during differentiation of human preadipocytes to fully developed fat tissue has been the aim of various studies in the past decades. Due to the lack of suitable human cell culture lines, experimental research predominantly focused on rodent models and nonhuman cell culture systems. Here, we demonstrate that a human preadipocyte cell line SGBS is well suited to examine differential expression of the Acyl-CoA binding protein (ACBP) during adipogenesis. The Acbp gene expresses various alternative high- and low-abundant transcript variants encoding ACBP protein isoforms, which play a central role in fat metabolism. Whereas the low-abundant transcript Acbp-1G is downregulated during SGBS adipogenesis, the high-abundant and well established transcripts Acbp-1A (1) and -1B are moderately (2-4-fold) upregulated. In contrast, the alternative high-abundant transcript Acbp-1C is strongly (29-fold) upregulated at mRNA and protein level indicating that particularly ACBP-1C functions in lipogenic processes during fat cell differentiation in humans.

Pseudo-dynamic contact surface areas: estimation of apolar bonding.

A new Monte Carlo based algorithm has been written for the computation of pseudo-dynamic contact surface areas. The linear correlation of this contact area with solute transfer free energies (water leads to organic liquid) is established for apolar amino acid side chains. The slope of these linear plots, deltaGosp, is a unitary free energy which has potential use in the estimation of apolar bond free energies in proteins. The magnitude of deltaGosp is dependent upon the nature of the organic solvent involved in the transfer process, varying from 86 to 130 cal/A2. Analogues linear correlations with the same range of deltaGosp values are observed for inhibitors of protein-catalyzed reactions.

The 'knotting' problem in proteins. Loop penetration.

The 'knotting' problem in proteins is redefined in terms of the more general concept of loop penetration. Disulfide-containing proteins are represented as linear graphs, and it is proposed that proteins with nonplanar graph representations display loop penetrations in their three-dimensional structure. With this argument, it is shown that the occurrence of loop penetration in disulfide-containing proteins is approximately that expected based on the random pairing of sulfhydryl groups. It is argued that loop penetration is not as rare as currently held.

Catalytic activity of Ntau-carboxymethylhistidine-12 ribonuclease: pH dependence.

The pH-dependence of RNAase A and of Ntau-carboxymethylhistidine-12-RNAase (ribonucleate 3'-pyrimidino-oligonucleotidohydrolase) catalysis was studied. Apparent acid dissociation constants were obtained by least squares analysis of the kinetics data. These dissociation constants were compared with pKa values of model imidazole compounds, and with pKa values of histidine residues 12 and 119 on the protein. The shapes of the kcat versus pH profiles for RNAase A and its carboxymethyl derivative are very similar, from which it is concluded that the mechanism of catalysis is closely similar in the two proteins. Apparent pKa values obtained from the kinetic data are higher for the carboxymethylated protein than for RNAase A, as are the pKa values of residues 12 and 119. The similar shifts are consistent with the conclusions that both these residues are functionally significant in native and modified enzyme, and that an unblocked tau-nitrogen on histidine-12 is not essential for activity. From the enzyme's catalytic dependence on pH, and the NMR determined pKa values we propose that histidine 12 and 119 function catalytically in their basic and acidic forms respectively.

Long range electron transfer along an alpha-helix.

The many observations of long range electron transfer in proteins raises the question of whether a protein's structure can influence the rate or path of such transfers, and if so, then how. To answer these questions requires information on which of the various structural elements composing proteins support long range electron transfer. In this report, we present evidence for long range electron transfer along the alpha-helix of a synthetic leucine zipper dimer. We also present electron transfer rate data obtained with other helical peptides.

Long range electron transfer between tyrosine and tryptophan in hen egg-white lysozyme.

The azide, dibromide and dichloride radicals oxidize one or more tryptophan side chains in hen egg-white lysozyme. The indolyl radical produced in this second-order 1-electron oxidation subsequently oxidizes a tyrosine side chain to the phenoxy radical in an intramolecular reaction with a rate constant of 130 +/- 10 s-1 at pH 7, 25 degrees C. The final indolyl and phenoxy equilibrium mixture then decays with a t1/2 approximately 2 s. The faster intramolecular reaction exhibits a pH dependence; on decreasing the pH from 9 the first-order rate constant increases to a maximum near pH 5.4 and then declines as the pH is lowered further. In contrast, the first-order rate constant for the intramolecular electron transfer between the tyrosine and tryptophan of the peptide trpH-pro-tyrOH remains unchanged between approx. pH 11 and 6.5 and then increases as the pH is lowered further. This difference in the observed pH dependence suggests that changes in structure or ionization state influence the protein electron transfer rate. We also discuss the radiation inactivation of lysozyme in light of these observations.

Carbamazepine compared with lithium in the treatment of mania.

Fifty-two hospitalized manic patients were randomized to treatment with either carbamazepine or lithium carbonate after a 2-week drug withdrawal period. All of the probands were tertiary referrals with a high proportion of failures of previous lithium and other treatment. Weekly ratings of manic, depressive, and psychotic symptoms were obtained for 8 weeks, and responders were followed up for up to 2 years. One third of patients responded favorably. Double-blind assessments revealed no statistically reliable differences between the two treatment groups. Patients receiving carbamazepine were somewhat more manageable than patients treated with lithium early in the study, whereas lithium-treated patients remained longer in the follow-up phase. However, numbers of long-term survivors were too small to be conclusive. This study adds to the growing body of evidence that acutely manic patients respond as well to carbamazepine as to lithium. However, monotherapy with either drug is not sufficient for the majority of manic patients who are referred for tertiary care.

Electroconvulsive treatment compared with lithium in the management of manic states.

Thirty-four hospitalized manic patients were randomized to treatment with either lithium carbonate or an average series of nine bilateral electroconvulsive treatments (ECTs), followed by maintenance with lithium carbonate. Weekly ratings of manic, depressive, and psychotic symptoms were obtained for eight weeks, and patients were followed up monthly for up to two years. Ratings by nonblind and blind observers indicated that the patients who underwent ECT improved more during the first eight weeks than did patients who were treated with lithium carbonate. This was especially true of patients with mixed symptoms of mania and depression and/or extreme manic behavior. Clinical ratings after eight weeks showed no significant differences between the lithium carbonate- and ECT-treated patients. Likewise, the two groups had comparable rates of relapse, recurrence, and rehospitalization during the follow-up period.

Electroencephalographic findings in relation to diagnostic constructs in psychiatry.

A group of 759 patients with final DSM-I and -II diagnoses of schizophrenia was identified among a cohort of 1494 adults who were hospitalized between 1965 and 1972. Admission EEG recordings were done in each patient during waking, activation procedures, drowsiness, and sleep. All cases were reclassified according to the Feighner et al. criteria, and relationships between the EEG, reassigned diagnosis, and outcome were examined. One-third of the schizophrenics were rediagnosed as having affective, organic, or other disorders. EEG abnormalities predicted diagnostic change and relatively favorable prognosis. Mean alpha frequencies were slower in schizophrenics than in patients with other DSM I-II disorders, and less in patients with Feighner et al. diagnoses of schizophrenia than in some rediagnosed categories. In 1980-82, matched samples from the original cohort with affective, schizophrenic, and mixed Feighner et al. diagnoses were followed and evaluated blindly with the SADS-L. RDC follow-up diagnoses were significantly correlated with the index EEG findings in terms of higher alpha average frequencies proportional to the amount of affective psychopathology. A subgroup of high functioning individuals within the RDC schizophrenic category was identified with affective symptomatology early in the course of illness, normal EEGs, and high alpha average frequencies. Patients with a consistent diagnosis of schizophrenia according to the three nosologic systems were shown to function better in some areas if the index EEG was abnormal. Discriminant function analysis established that DSM-I and -II categories possessed the greatest long-term predictive accuracy which was enhanced by the EEG diagnosis and alpha average to a level of more than 50%. The Feighner et al. and RDC diagnostic systems were not as relevant for prediction of long-term follow-up status.

Manic symptoms: an indication for bilateral ECT.

As a follow-up to pilot observations that six manic patients who failed to respond to unilateral electroconvulsive therapy (ECT) recovered rapidly when switched to bilateral treatment, a retrospective study was conducted. Twenty-five patients who responded after switchover from unilateral to bilateral ECT, 25 age- and sex-matched controls, and 25 concurrent controls who responded to right unilateral ECT alone were evaluated. Demographic variables and DSM-III diagnosis did not discriminate between the groups, nor were they different in terms of electroencephalographic (EEG) findings, neuropsychological test results, numbers of ECT, and duration of seizure discharges. Standard assessments of psychopathology performed by independent psychiatrists showed no differences in ratings of psychosis or depressive phenomena. However, scales assessing manic symptoms showed highly significant differences with many more features of unrestrained behavior, elevated mood, hurried speech, and other typical features of mania in the patients who were switched from unilateral to bilateral ECT. Although there were no differences in prescribed drugs, the use of prn medications for sleep was greater in the experimental-switched patients than in controls. Patients who responded to unilateral ECT alone exhibited virtually no manic features, whereas those who demonstrated these characteristics failed to respond to unilateral ECT but benefited when switched to bilateral treatment.

Trazodone, a new antidepressant: efficacy and safety in endogenous depression.

The effectiveness of trazodone was assessed over a 4-week period under double-blind conditions. Twenty-eight inpatients with a diagnosis of endogenous depression received either trazodone, imipramine, or placebo. Trazodone was significantly better than placebo and frequently better than imipramine according to analyses of the results of the Hamilton Psychiatric Scale for Depression, severity of illness and clinical global improvement ratings, and the Global Ward Behavior Scale. Significant improvement was evident in the trazodone group by the end of the first week of therapy, particularly in those symptoms associated with depression and accompanying anxiety. There were fewer side effects with trazodone than with imipramine.

Clinical and quantitative EEG studies of mania.

BACKGROUND: Earlier EEG studies reported essentially normal findings during acute manic episodes but some atypical EEG characteristics and distinctions between familial and sporadic cases were described. Recently quantitative EEG (qEEG) studies differentiating mania from schizophrenia and depression have been published. METHODS: Clinical EEGs were obtained in 202 patients hospitalized for acute mania. EEGs were repeated in 75 patients rehospitalized for subsequent manic attacks. Quantitative EEGs were recorded in 37 patients who were able to cooperate after drug washout and again on completion of randomly assigned pharmacotherapy. RESULTS: Normal EEGs were obtained in most patients. Moderately abnormal EEGs in 16% were significantly associated with absent family histories of affective disorder. Left sided abnormalities were more common than right. "Small sharp spikes" and "microsleep" were encountered in 17% and 10% respectively of patients who drowsed. EEG findings during subsequent episodes did not suggest increasing CNS vulnerability. qEEGs showed significant differences between each of the therapeutic agents compared-lithium, carbamazepine, and lithium combined with carbamazepine, haloperidol or risperidone. Nonresponders at baseline had significantly more diffuse theta activity than responders. During pharmacotherapy nonresponders had higher amplitudes in the left temporoparietal areas. LIMITATION: Clinical EEG findings confirmed previous reports but did not contain original observations. Applications of qEEG were limited by requirements for patient cooperation.

Topographic EEG studies of mania.

QEEG findings from 39 hospitalized manic patients were accomplished after a drug free period and following pharmacotherapy with lithium or carbamazepine alone or lithium combined with carbamazepine, haloperidol or risperidone. A subsample of 10 drug-free manic patients was compared with normal controls, which revealed lower qEEG amplitudes in the left anterior and midtemporal regions in the patients. Comparisons of drug therapies showed increased delta amplitudes and total power with lithium compared with carbamazepine. Increased fast frequencies were observed in the lithium and carbamazepine plus lithium groups compared with carbamazepine alone. Comparisons of the three drug combination groups revealed increased alpha and beta 1 amplitudes, most with risperidone and least with carbamazepine. Anterior delta and beta 2 amplitudes and interhemispheric coherence were increased directly proportional to plasma lithium levels. Nonresponders to treatment were identified at baseline by increased generalized theta amplitudes. After treatment, the nonresponders had higher amplitudes in the left temporal areas. Numerous qEEG associations with individual ratings of manic symptoms were found, more at baseline than after treatment. In general levels of psychopathology were negatively correlated with qEEG amplitudes. The qEEG findings appear to implicate dominant temporal lobe dysfunctions in mania.

Nonendemic pemphigus foliaceus presenting as fatal bullous exfoliative erythroderma.

Pemphigus foliaceus is a cutaneous autoimmune blistering disease that is characterized by lower morbidity and mortality than those observed in pemphigus vulgaris or paraneoplastic pemphigus. However, erythrodermic forms of the endemic variant of pemphigus foliaceus have been associated with a higher mortality. We report a case of nonendemic pemphigus foliaceus that presented as fatal bullous exfoliative erythroderma, and thus, we will emphasize the inclusion of this entity in the differential diagnosis and the use of skin direct immunofluorescence in the evaluation of patients with erythroderma.

[Silicone molding compounds and latex gloves. The effect of latex gloves on addition and condensation silicones]. / Silikonabformmassen und Latexhandschuhe. Der Einfluss von Latexhandschuhen auf Additions- und Kondensationssilikone.

Inhibited setting of addition silicones has been observed using latex gloves in the dental office. Therefore four addition silicones as well as four condensation silicones were mixed with seven latex gloves with different properties (sterility, powder, accelerator, inner layer). The masses were mixed with bare hands as a control and--additionally--with powdered hands. Condensation silicones stayed unaffected when put together in exact amounts, while some addition silicones showed nearly complete inhibition. Mixing the condensation silicones under the conditions of daily practice--one spoon of body plus a distinct amount of catalyst-resulted in hardness differences compared to using the exact dose. Nevertheless the resulting impressions were of satisfying quality. The powder-component (Bio-sorb, Surgikos) leads to an accelerated setting. The general dental practitioner/dental hygienist have to consider these aspects while choosing gloves and silicone putties for taking impressions.