Stability and proteolytic domains of Nef protein from human immunodeficiency virus (HIV) type 1

Proteolytic experiments in conjunction with 1H-NMR spectroscopy show that the Nef (negative factor) protein from human immunodeficiency virus type 1 probably consists of two main domains, the N-terminal anchor domain at amino acid positions 2-65 and the C-terminal core domain at positions 66-206. The N-terminal domain is likely to be located at the surface of the protein, while the C-terminal domain has a compactly folded core and is stable in the absence of the anchor domain. It is conceivable that the core domain represents a functional domain of the Nef protein, activated after the removal of the membrane anchor by the human-immunodeficiency-virus protease or cellular proteases. Nef is stable at pH 5-12 and denatures at 317-322 K. The Nef protein remains in its native conformation in dimethyl-sulfoxide/water mixtures up to 35% (by vol.), and in acetonitrile/water up to 14% (by vol.). Nef refolds spontaneously after denaturation with urea or guanidinium hydrochloride. The 1H-NMR parameters and pKa values of five of the nine histidine residues and one of the seven tyrosine residues were determined and were found in four cases to be typical for residues which are not located in the interior of the protein.

VIP36, a novel component of glycolipid rafts and exocytic carrier vesicles in epithelial cells

In simple epithelial cells, apical and basolateral proteins and lipids in transit to the cell surface are sorted in the trans-Golgi network. We have recently isolated detergent-insoluble complexes from Madin-Darby canine kidney cells that are enriched in glycosphingolipids, apical cargo and a subset of the proteins of the exocytic carrier vesicles. The vesicular proteins are thought to be involved in protein sorting and include VIP21-caveolin. The vesicular protein VIP36 (36 kDa vesicular integral membrane protein) has been purified from a CHAPS-insoluble residue and a cDNA encoding VIP36 has been isolated. The N-terminal 31 kDa luminal/exoplasmic domain of the encoded protein shows homology to leguminous plant lectins. The transiently expressed protein is localized to the Golgi apparatus, endosomal and vesicular structures and the plasma membrane, as predicted for a protein involved in transport between the Golgi and the cell surface. It is diffusely localized on the plasma membrane but can be redistributed by antibody modulation into caveolae and clathrin-coated pits. We speculate that VIP36 binds to sugar residues of glycosphingolipids and/or glycosylphosphatidyl-inositol anchors and might provide a link between the extracellular/luminal face of glycolipid rafts and the cytoplasmic protein segregation machinery.

Dose-response study of N,N-dimethyltryptamine in humans. II. Subjective effects and preliminary results of a new rating scale

BACKGROUND

Validation of animal models of hallucinogenic drugs' subjective effects requires human data. Previous human studies used varied groups of subjects and assessment methods. Rating scales for hallucinogen effects emphasized psychodynamic principles or the drugs' dysphoric properties. We describe the subjective effects of graded doses of N,N-dimethyltryptamine (DMT), an endogenous hallucinogen and drug of abuse, in a group of experienced hallucinogen users. We also present preliminary data from a new rating scale for these effects.

METHODS

Twelve highly motivated volunteers received two doses (0.04 and 0.4 mg/kg) of intravenous (IV) dimethyltryptamine fumarate "nonblind," before entering a double-blind, saline placebo-controlled, randomized study using four doses of IV DMT. Subjects were carefully interviewed after resolution of drug effects, providing thorough and systematic descriptions of DMT's effects. They also were administered a new instrument, the Hallucinogen Rating Scale (HRS). The HRS was drafted from interviews obtained from an independent sample of 19 experienced DMT users, and modified during early stages of the study.

RESULTS

Psychological effects of IV DMT began almost immediately after administration, peaked at 90 to 120 seconds, and were almost completely resolved by 30 minutes. This time course paralleled DMT blood levels previously described. Hallucinogenic effects were seen after 0.2 and 0.4 mg/kg of dimethyltryptamine fumarate, and included a rapidly moving, brightly colored visual display of images. Auditory effects were less common. "Loss of control," associated with a brief, but overwhelming "rush," led to a dissociated state, where euphoria alternated or coexisted with anxiety. These effects completely replaced subjects' previously ongoing mental experience and were more vivid and compelling than dreams or waking awareness. Lower doses, 0.1 and 0.05 mg/kg, were primarily affective and somaesthetic, while 0.1 mg/kg elicited the least desirable effects. Clustering of HRS items, using either a clinical, mental status method or principal components factor analysis provided better resolution of dose effects than did the biological variables described previously.

CONCLUSIONS

These clinical and preliminary quantitative data provide bases for further psychopharmacologic characterization of DMT's properties in humans. They also may be used to compare the effects of other agents affecting relevant brain receptors in volunteer and psychiatric populations.

Purification and properties of the squalene-hopene cyclase from Rhodopseudomonas palustris, a purple non-sulfur bacterium producing hopanoids and tetrahymanol

The squalene-hopene cyclase of the hopanoid- and tetrahymanol-producing Rhodopseudomonas palustris was released from the isolated membranes by CHAPS and purified to homogeneity by successive chromatography on DEAE Sephacel, Octyl Sepharose, and Blue Sepharose. The enzyme has a molecular weight of 70 kDa as determined by SDS-PAGE and an isoelectric point at about pH 5.0. The enzyme activity has a maximum at 30 degrees C and at pH 6.5. No production of tetrahymanol could be demonstrated by using either crude or purified cyclase preparations.

A novel peptide in the AKH/RPCH family isolated from the corpora cardiaca of the Emperor dragonfly, Anax imperator

Using a heterologous (in locusts and cockroaches) and a homologous bioassay, we have isolated the neuropeptide pGlu-Val-Asn-Phe-Ser-Pro-Ser-Trp-NH2 from extracts of corpora cardiaca of the Emperor dragonfly, Anax imperator. The sequence elucidation was achieved by Edman degradation of the deblocked peptide and by electrospray mass spectrometry. Low concentrations of the synthetic peptide injected into the Emperor dragonfly increased the hemolymph lipid concentration, suggesting a possible role of the peptide in lipid homeostasis during flight. Therefore, it is named Ani-AKH, Anax imperator adipokinetic hormone.

Psychosomatic syndromes, somatization and somatoform disorders

A psychosomatic syndrome is defined as a syndrome in which psychological processes play a substantial role in the etiology of the illness in some of the patients. The main conclusions on the extent of the biological and psychosocial contributions to several psychosomatic syndromes are presented and the relationship of these syndromes to somatization and somatoform disorders is discussed. The syndromes summarized include fibromyalgia, chronic fatigue, motility disorders of the esophagus, nonulcer dyspepsia, irritable bowel syndrome, urethral syndrome, behaviors causing disturbances of physiology, and some defined pain syndromes. The findings suggest that the extent of the biological and psychosocial contributions vary among these syndromes as well as among individuals with the same syndrome. In some syndromes the extent and nature of the biological contribution has not been established with certainty. There is evidence to suggest that many of the phenomena of the somatoform disorders are caused by clustering of psychosomatic syndromes or their incomplete or atypical manifestations and a low sensation threshold. The results of the controlled studies of various methods of psychotherapy and drug treatments of the psychosomatic syndromes are listed; these studies have practical implications because the adoption of these methods is likely to enhance the efficacy of the treatment of somatoform disorders.

Imagery rehearsal treatment of chronic nightmares: with a thirty month follow-up

Nightmare frequency and self-rated distress were assessed retrospectively in two groups of chronic nightmare sufferers 30 months after treatment. In the initial phase, the image group (N = 9) learned a cognitive-behavioral technique (imagery rehearsal) for the treatment of nightmares. They were taught in one group session to: (1) record a nightmare; (2) change it (usually to something positive); and (3) rehearse the new images daily. The record group (N = 10) recorded nightmares during the first month only and learned imagery rehearsal subsequent to 3-month follow-up measurements. At 3 months and at 30 months, both groups had significantly fewer nightmares, but only the rehearsal group had less total distress. The results support the theory that nightmares are a primary sleep disorder rather than a symptom of an underlying psychiatric problem.

Staging: a neglected dimension in psychiatric classification

The staging method, whereby a disorder is characterized according to seriousness, extension and features, has achieved wide currency in medicine but is currently neglected in psychiatry. Studies addressing or related to the issue of staging in schizophrenia, unipolar depression, bipolar disorder and panic disorder are discussed. The phenomenological development of these mental disorders may be categorized according to stages.

Annexin II is a major component of fusogenic endosomal vesicles

We have used an in vitro assay to follow the proteins transferred from a donor to an acceptor upon fusion of early endosomes. The acceptor was a purified early endosomal fraction immunoisolated on beads and the donor was a metabolically-labeled early endosomal fraction in suspension. In the assay, both fractions were mixed in the presence of unlabeled cytosol, and then the beads were retrieved and washed. The donor proteins transferred to the acceptor were identified by two-dimensional gel electrophoresis and autoradiography. Approximately 50 major proteins were transferred and this transfer fulfilled all criteria established for endosome fusion in vitro. However, only a small subset of proteins was efficiently transferred, if donor endosomes were briefly sonicated to generate small (0.1 micron diam) vesicles before the assay. These include two acidic membrane proteins, and three alkaline peripheral proteins exposed on the cytoplasmic face of the membrane. Partial sequencing and Western blotting indicated that one of the latter components is annexin II, a protein known to mediate membrane-membrane interactions. Immunogold labeling of cryosections confirmed that annexin II is present on early endosomes in vivo. These data demonstrate that annexin II, together with the other four proteins we have identified, is a major component of fusogenic endosomal vesicles, suggesting that these proteins are involved in the binding and/or fusion process.

Comorbidity in panic disorder: II. Chronology of appearance and pathogenic comorbidity

Ages of onset and the sequence of appearance of panic disorder (PD) and comorbid conditions were determined in a sample of 54 patients with the principal DSM-III-R diagnosis of PD. The onset of PD was earlier in patients with moderate to severe agoraphobia (AG) than in panic patients without AG. Patients with alcohol abuse and drug abuse before the onset of PD also had a tendency to develop PD earlier, which suggests that these conditions might have specifically predisposed to PD. All comorbid disorders, except for major depression, were more likely to precede the onset of PD so that, more often than not, PD appeared as a chronologically secondary condition. However, it was found that only for primary substance abuse such a temporal relationship might denote etiologic relatedness to PD, because of the reduced temporal distance between the onset of primary substance abuse and secondary PD.

Comparison of primary and secondary panic disorder: a preliminary report

We examined the onsets of comorbid psychiatric disorders in patients with panic disorder (PD) (N = 54). In 42 patients (77.8%), PD was preceded by another psychiatric condition (secondary PD group), while in 12 patients (22.2%), PD occurred first or was the only diagnosed mental disorder (primary PD group). Patients with primary and secondary PD did not differ with respect to demographic variables, mean ages of onset of PD, mean duration of PD, number of patients with a personality disorder, and number of patients with different DSM-III-R subtypes of PD. Except for the anger and sleep scales of the Hopkins Symptom Checklist 90, patients with primary PD had significantly less self-rated psychopathology; they also displayed less extensive phobic avoidance, and had a lower rate of current psychiatric comorbidity. These findings are discussed in light of the value of the concepts of comorbidity and primary/secondary dichotomy.

The phenomenology of panic attacks in panic disorder with and without agoraphobia

The frequency of symptoms during panic attacks and anticipation of the panic consequences were compared in patients with the subtypes of panic disorder (PD). Patients with moderate and severe agoraphobic avoidance reported that they had experienced more symptoms than patients with an uncomplicated PD (without agoraphobia [AG]); they also experienced almost all of the symptoms more frequently, with the difference being significant for a quarter of the examined panic symptoms. Panic patients with moderate and severe AG were also significantly more concerned about the loss of control and social and physical consequences of panic attacks. Taken together, these findings suggest that the severity of panic attacks, defined as the number of panic symptoms, along with a variety of anticipatory fears about the consequences of the attacks may contribute to the development of AG in panic patients.

A tryptophan-substituted member of the AKH/RPCH family isolated from a stick insect corpus cardiacum

A neuropeptide, Cam-HrTH-I, has been isolated from the corpus cardiacum of the Indian stick insect Carausius morosus. The peptide causes hyperlipaemia in Locusta migratoria and hypertrehalosaemia in Periplaneta americana and is related to the previously isolated Cam-HrTH-II (pGlu-Leu-Thr-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2) by substitution, apparently by a hexose, on the Trp residue. This appears to be the first example of such substitution on a Trp residue.

Purification, characterization and structure of protein phosphatase 1 from the cilia of Paramecium tetraurelia

A type 1 serine/threonine protein phosphatase (PP1) which is mostly localized in the excitable ciliary membranes from the protozoan Paramecium, was purified to homogeneity. Approximately 4 micrograms enzyme of 37 kDa was isolated from 100 l axenic culture. The enzymic properties were characterized using phosphorylase a from rabbit skeletal muscle as a substrate and several known effectors of mammalian PP1. The protozoan PP1 was enzymically indistinguishable from its mammalian congener. The amino acid sequence of the Paramecium PP1 was deduced from its cDNA. The full-length clone was obtained in several steps starting with a pair of degenerate primers made according to the two most conserved peptides of rabbit PP1 and PP2A. The gene encodes a protein of 36,392 Da. The identity of the cloned gene and the isolated ciliary PP1 was unequivocally established by microsequencing of four tryptic and cyanogen-bromide peptides which were generated from the purified protein. Paramecium PP1 shows 75% amino-acid-sequence identity with rabbit PP1 alpha. Areas of major differences are the C-termini and N-termini and a sequence between residues 219-242.

The beneficial effects of one treatment session and recording of nightmares on chronic nightmare sufferers

Twenty subjects with chronic nightmares for 17.2 years mean duration were randomly divided into two groups: Rehearsal and Recording. At inception, subjects in both groups were instructed to write down their nightmares for one month. The Recording group received no other intervention. Rehearsal subjects received a single treatment group session teaching an imagery rehearsal technique to reduce nightmare frequency. At inception and three months follow-up, both groups were compared for nightmare frequency and for self-rated distress with scales (Symptom Checklist and Symptom Questionnaire) measuring anxiety, depression, hostility, somatization and total distress. Nightmare frequency decreased significantly in both groups: Rehearsal group-7.2 per month to 2.0 per month (72% reduction) (p < 0.006); Recording group-9.4 per month to 5.0 per month (47% reduction) (p < 0.02). There were no statistically significant differences in the nightmare frequency reductions between groups. All anxiety, depression, somatization, hostility and total distress scores decreased substantially in the Rehearsal group. Most changes were significant. Changes in the Recording group were inconsistent and not significant. Two brief case histories are presented.

Interactions of rab5 with cytosolic proteins

Rab proteins, one of the subfamilies of ras-like small GTP-binding proteins, are attached to cellular compartments or transport vesicles and may determine the specificity of fusion between these compartments and vesicles. It has been proposed that they alternate between a membrane-bound and a cytosolic state during their functional cycle. We have used a photo-crosslinking approach to identify their cytosolic interaction partners. In vitro synthesized rab5 was cross-linked in the presence of ATP mainly to three cytosolic proteins of 52, 65, and 85 kDa. Sucrose density gradient centrifugation of the cross-linked products suggested that they were part of a 10-14 S complex. Furthermore, rab5 was cross-linked to these and additional cytosolic proteins of 42, 48, and 160 kDa in the absence of ATP. Unexpectedly, upon ATP depletion of the cytosol cross-linked and noncross-linked rab5 was found in a sedimentable high molecular weight structure. Other members of the rab subfamily, but not N-ras, also sedimented under these conditions. Electrophoretic and electron microscopic analysis of the pelleted material revealed that it contained actin filament bundles and intermediate filaments. Our data suggest that cytosolic rab proteins interact with several proteins in a 10-14 S complex, and that the rab proteins may interact directly or indirectly via this complex with the cytoskeleton.

VIP21, a 21-kD membrane protein is an integral component of trans-Golgi-network-derived transport vesicles

In simple epithelial cells, apical and basolateral proteins are sorted into separate vesicular carriers before delivery to the appropriate plasma membrane domains. To dissect the putative sorting machinery, we have solubilized Golgi-derived transport vesicles with the detergent CHAPS and shown that an apical marker, influenza haemagglutinin (HA), formed a large complex together with several integral membrane proteins. Remarkably, a similar set of CHAPS-insoluble proteins was found after solubilization of a total cellular membrane fraction. This allowed the cloning of a cDNA encoding one protein of this complex, VIP21 (Vesicular Integral-membrane Protein of 21 kD). The transiently expressed protein appeared on the Golgi-apparatus, the plasma membrane and vesicular structures. We propose that VIP21 is a component of the molecular machinery of vesicular transport.