A lipid droplet-specific capsule is present in rat adrenal cells: evidence from a monoclonal antibody.

We have used a monoclonal antibody, A2, to study the structure and function on the lipid droplet capsule in steroidogenic adrenal cells. This antibody reacts with a 160-kD protein found in the rat adrenal cortex. Immunofluorescence microscopy shows a dominant rim pattern, which surrounds individual lipid droplets and is distinct from the filamentous vimentin staining.

Identification of a series of 3-(benzyloxy)-1-azabicyclo[2.2.2]octane human NK1 antagonists.

The synthesis and in vitro and in vivo evaluation of a series of 3-(benzyloxy)-1-azabicyclo-[2.2.2]octane NK1 antagonists are described.

GM1 and NGF synergism on choline acetyltransferase and choline uptake in aged brain.

In the brain of aged rats high affinity choline uptake (HAChU) of the striatum, hippocampus, and frontal cortex is lower than in young rats, while choline acetyltransferase (ChAT) activity is lower in striatum and frontal cortex. Infusion into the lateral cerebral ventricle with nerve growth factor (NGF) enhances the low values of these cholinergic markers in a dose- and region-dependent manner. GM1 ganglioside infused into the lateral ventricle, at a dose that is ineffective alone, together with NGF synergistically enhances the effect of NGF on ChAT and HAChU activities in the brain of aged animals.

MR findings in methanol intoxication.

We report the MR and CT findings with pathologic correlation in a case of severe methanol intoxication. There was bilateral hemorrhagic necrosis of the putamen and caudate nuclei and, in addition, extensive subcortical necrosis and symmetric bilateral necrosis of the pontine tegmentum and optic nerves, which may indicate poor prognosis.

Hepatic involvement in mastocytosis: clinicopathologic correlations in 41 cases.

Mastocytosis is a disease of mast cell hyperplasia that may involve several organ systems, including liver. Between 1988 and 1991, we conducted a retrospective-prospective study of 41 patients with mastocytosis and found 61% had evidence of liver disease. Hepatomegaly was detected in 24%, splenomegaly in 41%, and elevated serum alkaline phosphatase, serum aminotransaminases, 5'nucleotidase, or gamma-glutamyltranspeptidase (GGTP) in 54% of the patients.

Substance P (NK1)- and neurokinin A (NK2)-receptor gene expression in inflammatory airway diseases.

The tachykinin neuropeptides substance P and neurokinin (NK) A have been postulated to participate in the inflammatory reaction in airways of smokers and asthmatics. We have examined the hypothesis that the expression of one or more of the three cloned tachykinin receptors (NK1, NK2, and NK3) is increased in inflammatory airway disorders, which could result in augmentation of the effect of released tachykinin neuropeptides. NK1 receptor and NK2 receptor but not NK3-receptor mRNA were detected by ribonuclease protection assay in RNA from both cartilaginous and membranous bronchi and subpleural lung.

Identification of residues involved in ligand binding to the neurokinin-2 receptor.

Several residues of the human neurokinin-2 receptor have been identified to be critical for the binding of peptide agonists and non-peptide antagonists. Amino acid substitutions in the first and second extracellular segments and the second transmembrane segment led to substantial reduction in peptide affinity without affecting the affinity of antagonist SR48968. These effects are identical to those observed for homologous residues in the neurokinin-1 receptor, suggesting that these three regions are involved in high-affinity peptide binding to both receptor subtypes.

Molecular characterization of a common binding site for small molecules within the transmembrane domain of G-protein coupled receptors.

The cloning of over 100 members of the superfamily of G-protein coupled receptors has resulted in the identification and characterization of novel targets for therapeutic intervention. In addition, mutagenesis studies aimed at understanding the nature of the molecular interactions of these receptors with peptides and small molecules have led to advancements in the ability to synthesize novel therapeutic agents with high affinity and specificity for these receptors. These experiments have shown that there is a common binding site for small molecules within the transmembrane domain of G-protein coupled receptors regardless of the nature of the endogenous, physiologically relevant receptor agonist.

Increased synovial expression of transforming growth factor (TGF)-beta receptor endoglin and TGF-beta 1 in rheumatoid arthritis: possible interactions in the pathogenesis of the disease.

The ingress of inflammatory cells into the rheumatoid (RA) synovial tissue (ST) plays a role in the pathogenesis of this disease. Transforming growth factor beta (TGF-beta) may play a role in this process. We have investigated the distribution of endoglin, a newly described receptor for TGF-beta 1 and -beta 3, in RA compared to osteoarthritis (OA) or normal ST.

Increased synovial expression of the adhesion molecules CD66a, CD66b, and CD31 in rheumatoid and osteoarthritis.

Leukocyte-endothelial interaction mediated by adhesion molecules may play a role in the ingress of inflammatory cells into the rheumatoid (RA) synovial tissue (ST). A number of these molecules have been shown to be up-regulated in the inflamed compared to normal ST. We studied the distribution of two members of the CD66 carcinoembryonic antigen adhesion molecule family, as well as that of CD31, an antigen structurally related to CD66, on various cell types in the RA compared to osteoarthritic (OA) and normal ST.

High dose intravitreal ganciclovir for CMV retinitis: a shelf life and cost comparison study.

Background: It was previously found that high dose intravitreal ganciclovir provided superior treatment of cytomegalovirus retinitis compared with intravenous treatment. This study examined the stability and solubility of the ganciclovir solution to determine the shelf life of prepared solution, and compared the cost of intravitreal with intravenous therapy.

Methods: For the solubility studies high performance liquid chromatography was used to determine the ganciclovir concentration in various solutions.

Mutational analysis of neurokinin receptor function.

The interactions of the NK1 receptor with peptide agonists or nonpeptide antagonists have been investigated by site-directed mutagenesis and computer modeling. At least 10 residues in the extracellular and transmembrane regions of the receptor are required for the binding of many peptide agonists. The C-terminal amide of peptide agonists is likely to be bound near Asn-85.

The family of G-protein-coupled receptors.

The family of G-protein-coupled receptors can be defined by their similar structural and functional characteristics. Although their primary sequences are quite diverse, these proteins share several common structural features that reflect their common mechanism of action. Mutagenesis and biophysical analysis of several of these receptors indicate that small molecule agonists and antagonists bind to a hydrophobic pocket buried in the transmembrane core of the receptor.

Systemic administration of GM1 ganglioside increases choline acetyltransferase activity in the brain of aged rats.

In the brain of aged rats (22-24 months old) choline acetyltransferase (ChAT) activity in striatum and frontal cortex is lower than in young rats (4-5 months old). In contrast, ChAT activity in the hippocampus is similar in the two groups. Treating old animals with GM1 ganglioside, 30 mg/kg ip, for 30 or 45 days enhances ChAT activity in the striatum and frontal cortex, but has no effect on activity in the hippocampus.

Synthesis and biological evaluation of NK1 antagonists derived from L-tryptophan.

The 3,5-bis(trifluoromethyl)benzyl ester of N-acetyl-L-tryptophan (3), which was derived from the screening lead N-ethyl-L-tryptophan benzyl ester, has been used as a starting point to identify high-affinity substance P receptor antagonists with improved in vivo activity. Altering the ester moiety to an amide or ether led to a substantial loss in binding affinity, but conversion to a ketone provided compounds with affinity comparable to the equivalent esters. A homochiral synthesis of the key intermediate amino ketone 15 was developed which allows its preparation on a large scale.

Raising the dose of interferon does not improve the response in chronic hepatitis C.

We report results of dose escalation to 5 or 6 million units (MU) three times weekly (t.i.w.

Magnetic resonance features in carbon monoxide poisoning.

The authors describe unusual magnetic resonance findings due to carbon monoxide poisoning in a 34-year-old woman. With T2-weighted imaging, increased signal intensity was observed bilaterally in the putamen and the caudate nucleus. Lesions of high signal intensity in the globus pallidus, which have been previously reported, were also observed.

Characterization of a fluorescent substance P analog.

We describe the development and characterization of substance P labeled at Lys3 with fluorescein ([fluorescein Lys3]SP) as a fluorescent probe for the neurokinin 1 (NK1) receptor. [fluorescein Lys3]SP is an agonist at the human NK1 receptor, with an affinity for both the high-affinity and low-affinity binding states of the receptor approximately 6-fold lower than that of substance P. Binding of the probe to the human NK1 receptor expressed in Sf9 insect cells was observed directly by monitoring either a decrease in fluorescence intensity or an increase in anisotropy of the [fluorescein Lys3]SP.

The physical state of the negative strand of hepatitis C virus RNA in serum of patients with chronic hepatitis C.

Negative strands of the hepatitis C virus (HCV) genome (a positive-stranded RNA virus) have been found in a nuclease-resistant form in the serum of patients with HCV infections. We determined whether a complete negative-strand copy is present in the serum, whether the negative strand is particle-associated, and finally, whether it is virion-associated and encapsidated like the positive (genomic) strand. Isopyknic sucrose and cesium chloride density ultracentrifugation followed by a strand-specific reverse transcription-polymerase chain reaction on the collected fractions was performed to determine whether both positive and negative strands were associated with similar particles.

Therapy of chronic hepatitis B with a 6-month course of ribavirin.

Ribavirin is a nucleoside analogue with broad spectrum antiviral activity that has been shown to inhibit viral replication in the woodchuck model of hepatitis B virus infection. We studied the effect of ribavirin on viral replication in 18 patients with chronic hepatitis B who were positive for hepatitis B e antigen. Patients were randomized to receive a 24-week course of oral ribavirin at a dose of either 800, 1000, or 1200 mg/kg per day.

Short-term prednisone therapy affects aminotransferase activity and hepatitis C virus RNA levels in chronic hepatitis C.

Background/aims: The effects of corticosteroids on chronic hepatitis B have provided insight into the mechanism of liver cell injury caused by hepatitis B. In this study, this model was applied to investigate the effects of prednisone on alanine aminotransferase (ALT) and hepatitis C virus (HCV) RNA levels in chronic hepatitis C.

Methods: Ten patients with chronic hepatitis C who had increased levels of ALT and HCV RNA detectable in serum were given a 7-week course of a tapering dose of prednisone.

High levels of viral replication during acute hepatitis B infection predict progression to chronicity.

To assess the pattern of development of serologic markers during acute hepatitis B, levels of HBsAg, HBeAg, and hepatitis B virus (HBV) DNA were assayed in stored serum samples obtained sequentially from 12 subjects infected with HBV during experimental studies conducted in the 1950s. Six patients developed acute self-limited hepatitis, three developed chronic hepatitis, and three had an asymptomatic infection without HBsAg. HBsAg was the first serologic marker detected (mean = 52 days after exposure), followed by HBeAg (62 days) and HBV DNA (72 days).

Interaction of glutamine 165 in the fourth transmembrane segment of the human neurokinin-1 receptor with quinuclidine antagonists.

Substance P binds to and activates the neurokinin-1 receptor with high affinity, thereby modulating several neuronal pathways including pain transmission and neurogenic inflammation. Several high affinity non-peptide antagonists have recently been described. To elucidate the molecular interactions specific for binding to the neurokinin-1 receptor, site-directed mutagenesis has been utilized to identify amino acid residues that interact directly with antagonists.

Production of angiogenic activity by human monocytes requires an L-arginine/nitric oxide-synthase-dependent effector mechanism.

Human monocytes (M phi) require stimulation with substances such as bacterial endotoxin [LPS (lipopolysaccharide)] to produce angiogenic activity. In this study, we report that stimulation of M phi with LPS (5 micrograms/ml) in the absence of L-arginine greatly reduced their production of angiogenic activity, as assessed in vivo in rat corneas and in vitro by chemotaxis of human umbilical vein endothelial cells (HU-VECs). D-Arginine did not substitute for L-arginine in the production of angiogenic activity.