Vasoactive intestinal peptide. Link between electrical activity and glia-mediated neurotrophism

Vasoactive intestinal peptide has neurotrophic and neuroprotective properties that influence the survival of activity-dependent neurons in the central nervous system. Investigations of the mechanism of this neurotrophic peptide indicated that these actions are contingent on interactions with astroglia. The complex mixture of neurotrophic mediators released from astroglia include cytokines, a protease inhibitor, and activity-dependent neurotrophic factor, a protein with apparent structural similarities to hsp60. Investigations of ADNF resulted in the discovery of active peptides of extraordinary potency and broad neuroprotective properties. These studies indicate that a nine-amino acid core peptide of ADNF had significantly greater neuroprotective properties in comparison to the parent growth factor and these advantages identify ADNF-9 as an attractive lead compound for drug development.

Evaluation of the susceptibility of Coccidioides immitis to lufenuron, a chitin synthase inhibitor

The activity of the chitin synthase inhibitor lufenuron was evaluated in vitro using the spherule-endospore (SE) phase of Coccidioides immitis. The lufenuron was also used to treat mice infected with C. immitis by the respiratory route. In vitro, lufenuron had no effect upon fungal cell growth. Two formulations of lufenuron were evaluated in vivo. Neither the oral nor the injectable lufenuron extended the survival of mice infected with C. immitis when compared with placebo-treated mice.

Locomotor activity causes a rapid up-regulation of vasoactive intestinal peptide in the rat hippocampus

Vasoactive intestinal peptide (VIP) expression is restricted to interneurons in the hippocampus of normal adult rats. However, 3-6 hours after a 60-minute walk in an activity wheel, VIP was transiently expressed in most pyramidal and granular neurons of the hippocampus. Locomotion was also associated with a dramatic increase in VIP immunoreactivity in the motor cortex, primarily in bipolar cells. Reverse transcriptase-polymerase chain reaction analysis indicated that VIP mRNA increases transiently by more than twofold, before the increases in peptide immunoreactivity in both the hippocampus and motor cortex. By comparison, another marker of inhibitory interneurons, glutamate decarboxylase, did not change its expression pattern after locomotion. The calcium binding protein, calbindin-D28K, normally expressed in interneurons, was now found also in glial cells of the hippocampus and motor cortex. Another marker of enhanced electrical activity, the immediate early gene, c-Fos, was expressed in pyramidal and granular neurons at 3 hours but not at 6 hours after locomotion. These results suggest that mapping of peptide expression in the brain of a docile, inactive rat may not reflect the real distribution and functions of a peptide in an active animal.

A rheumatoid factor specific mimotope identified by a peptide display library

We screened a 10 amino acid peptide display library in filamentous phage with B'20, a monoclonal high affinity IgM rheumatoid factor (RF) expressing the VkIIIa-dependent 4C9 idiotype. Using direct and indirect selection techniques, 12 B'20 reactive peptides were identified, 9 of which belonged to one of two motifs. Binding of B'20 to phage-bearing peptides was inhibited by both IgG and 4C9 antiidiotype. Synthetic peptides corresponding to the two motifs inhibited the Fc binding of a low avidity IgA B'20 construct. Purified IgM from 6/8 RF-positive RA patients and 8/11 monoclonal RFs with VkIII-encoded light chains bound to the phage, whereas none of the four monoclonal RFs with VkI or VkII encoded light chains bound. Phage binding appeared to be RF specific. Three 4C9 positive/RF negative cell lines from RA patients did not bind to phage nor did three B'20 mutants that had lost RF specificity, whereas two mutants that retained RF specificity also retained phage binding. We propose that there is a common epitope(s) recognized by VkIII encoded RFs that is mimicked by the structure of these peptides. Such mimotopes might be exploited to design novel agents that interfere with autoantibody binding.

Duration of apnoea with two different intubating doses of remifentanil

We have studied the apnoea time after induction with two successful drug intubating regimes, both containing remifentanil. Group 1 (n = 20); propofol 2 mg kg-1 and remifentanil 2 micrograms kg-1 and group 2 (n = 20); propofol 2 mg kg-1, remifentanil 1 microgram kg-1 and lignocaine 1 mg kg-1. Intubation was possible in all 40 patients, and regarded as acceptable in 90% and 85% of patients, respectively. The median time to the return of spontaneous respiration was 487 s in group 1 and 270 s in group 2 (P < 0.05). Median end-tidal CO2 concentration at the time of the first spontaneous respiration was 7.37 kPa in group 1 and 6.3 kPa in group 2 (P < 0.05). Both groups had a decrease in heart rate after induction, but this failed to reach either clinical or statistical significance, and no patient required atropine. Similarly, there was a decrease in arterial pressure after induction in both groups (P < 0.05), but this was not deemed to be clinically significant. Only two patients in each group required ephedrine 6 mg before arterial pressure was restored to within 25% of the base-line. Intubating conditions were similar in both groups, but group 2 provided a significantly shorter apnoea time.

An aggressive form of polyarticular arthritis in a man with CD154 mutation (X-linked hyper-IgM syndrome)

Hyper-IgM syndrome (HIM) is a rare immunodeficiency disorder that has been associated with the development of symptoms and clinical features characteristic of rheumatoid arthritis (RA). We describe a patient with HIM and severe erosive arthritis with prominent nodules in the absence of detectable serum rheumatoid factor. Because HIM results from defects in either T cell CD154 (CD40 ligand) expression or abnormal CD40 signaling, the molecular basis of the patient's disease was analyzed. Activated CD4+ T cells failed to express surface CD154 protein, and molecular analysis of CD154 complementary DNA revealed a nucleotide transversion resulting in the nonconservative amino acid substitution G-D at amino acid 257. This case indicates that defective CD154-dependent CD40 signaling can be associated with susceptibility to a severe inflammatory arthritis that has both similarities to and differences from idiopathic RA.

Mapping the active site in vasoactive intestinal peptide to a core of four amino acids: neuroprotective drug design

The understanding of the molecular mechanisms leading to peptide action entails the identification of a core active site. The major 28-aa neuropeptide, vasoactive intestinal peptide (VIP), provides neuroprotection. A lipophilic derivative with a stearyl moiety at the N-terminal and norleucine residue replacing the Met-17 was 100-fold more potent than VIP in promoting neuronal survival, acting at femtomolar-picomolar concentration. To identify the active site in VIP, over 50 related fragments containing an N-terminal stearic acid attachment and an amidated C terminus were designed, synthesized, and tested for neuroprotective properties. Stearyl-Lys-Lys-Tyr-Leu-NH2 (derived from the C terminus of VIP and the related peptide, pituitary adenylate cyclase activating peptide) captured the neurotrophic effects offered by the entire 28-aa parent lipophilic derivative and protected against beta-amyloid toxicity in vitro. Furthermore, the 4-aa lipophilic peptide recognized VIP-binding sites and enhanced choline acetyltransferase activity as well as cognitive functions in Alzheimer's disease-related in vivo models. Biodistribution studies following intranasal administration of radiolabeled peptide demonstrated intact peptide in the brain 30 min after administration. Thus, lipophilic peptide fragments offer bioavailability and stability, providing lead compounds for drug design against neurodegenerative diseases.

Synovial non-Hodgkin's lymphoma in a human immunodeficiency virus infected patient

We describe a case of articular non-Hodgkin's lymphoma (NHL) with malignant lymphoma cells observed in synovial fluid. Bone involvement in NHL is common, but an English language Medline search revealed only 14 reported cases of synovial NHL. Although NHL is a well recognized complication of human immunodeficiency virus (HIV) infection, this is the first report of synovial NHL in an HIV infected patient.

Complete sequence of a novel protein containing a femtomolar-activity-dependent neuroprotective peptide

The vulnerability of neurons and the irreversibility of loss make discoveries of neuroprotective compounds fundamentally important. Here, the complete coding sequence of a novel protein (828 amino acids, pI 5.99), derived from mouse neuroglial cells, is revealed. The sequence contained (1) a neuroprotective peptide, NAPVSIPQ, sharing structural and immunological homologies with the previously reported, activity-dependent neurotrophic factor; (2) a glutaredoxin active site; and (3) a zinc binding domain. Gene expression was enriched in the mouse hippocampus and cerebellum and augmented in the presence of the neuropeptide vasoactive intestinal peptide, in cerebral cortical astrocytes. In mixed neuron-astrocyte cultures, NAPVSIPQ provided neuroprotection at subfemtomolar concentrations against toxicity associated with tetrodotoxin (electrical blockade), the beta-amyloid peptide (the Alzheimer's disease neurotoxin), N-methyl-D-aspartate (excitotoxicity), and the human immunodeficiency virus envelope protein. Daily NAPVSIPQ injections to newborn apolipoprotein E-deficient mice accelerated the acquisition of developmental reflexes and prevented short-term memory deficits. Comparative studies suggested that NAPVSIPQ was more efficacious than other neuroprotective peptides in the apolipoprotein E-deficiency model. A potential basis for rational drug design against neurodegeneration is suggested with NAPVSIPQ as a lead compound. The relative enrichment of the novel mRNA transcripts in the brain and the increases found in the presence of vasoactive intestinal peptide, an established neuroprotective substance, imply a role for the cloned protein in neuronal function.

Mutational analysis of amino acid residues involved in argininosuccinate lyase activity in duck delta II crystallin

Delta-crystallins are the major structural eye lens proteins of most birds and reptiles and are direct homologues of the urea cycle enzyme argininosuccinate lyase. There are two isoforms of delta-crystallin, delta Iota and delta IotaIota, but only delta IotaIota crystallin exhibits argininosuccinate lyase (ASL) activity. At the onset of this study, the structure of argininosuccinate lyase/delta IotaIota crystallin with bound inhibitor or substrate analogue was not available. Biochemical and X-ray crystallographic studies had suggested that H162 may function as the catalytic base in the argininosuccinate lyase/delta IotaIota crystallin reaction mechanism, either directly or indirectly through the activation of a water molecule. The identity of the catalytic acid was unknown. In this study, the argininosuccinate substrate was modeled into the active site of duck delta IotaIota crystallin, using the coordinates of an inhibitor-bound Escherichia coli fumarase C structure to orient the fumarate moiety of the substrate. The model served as a means of identifying active site residues which are positioned to potentially participate in substrate binding and/or catalysis. On the basis of the results of the modeling, site-directed mutagenesis was performed on several amino acids, and the kinetic and thermodynamic properties of each mutant were determined. Kinetic studies reveal that five residues, R115, N116, T161, S283, and E296, are essential for catalytic activity. Determination of the free energy of unfolding/refolding of wild-type and mutant delta II crystallins revealed that all constructs exhibit similar thermodynamic stabilities. During the course of this work, the structure of an inactive delta IotaIota crystallin mutant with bound substrate was solved [Vallee et al. (1999) Biochemistry 38, 2425-2434], which has allowed the kinetic data to be interpreted on a structural basis.

Increased serum stromelysin-1 levels in systemic lupus erythematosus: lack of correlation with disease activity

OBJECTIVE

In view of evidence that stromelysin-1 and collagenase-1 are involved in tissue injury in inflammatory joint diseases, we sought to determine whether matrix metalloproteinases (MMP) are implicated in the pathophysiology of systemic lupus erythematosus (SLE).

METHODS

Seventy-three patients with SLE and 39 healthy subjects were evaluated. Serum levels of MMP and tissue inhibitor of metalloproteinases were measured.

RESULTS

Serum stromelysin-1 levels were significantly increased in patients with SLE (416+/-252 ng/ml) compared to healthy subjects (125+/-93 ng/ml). No correlation between serial measurements of stromelysin-1 and disease activity in SLE patients was noted. Serum collagenase-1, gelatinase A, and TIMP-1 levels were not increased in SLE.

CONCLUSION

Serum concentrations of stromelysin-1 are increased in SLE, but the levels do not correlate with disease activity.

VIP neurotrophism in the central nervous system: multiple effectors and identification of a femtomolar-acting neuroprotective peptide

Vasoactive intestinal peptide has neurotrophic and growth-regulating properties. As in the case of many neurotrophic molecules, VIP also has neuroprotective properties, including the prevention of cell death associated with excitotoxicity (NMDA), beta-amyloid peptide, and gp120, the neurotoxic envelope protein from the human immunodeficiency virus. The neurotrophic and neuroprotective properties are mediated in part through the action of glial-derived substances released by VIP. These substance include cytokines, protease nexin I, and ADNF, a novel neuroprotective protein with structural similarities to heat-shock protein 60. Antiserum against ADNF produced neuronal cell death and an increase in apoptotic neurons in cell culture. A 14 amino acid peptide (ADNF-14) derived from ADNF has been discovered that mimics the survival-promoting action of the parent protein. These studies support the conclusion that VIP, PACAP, and associated molecules are both important regulators of neurodevelopment and strong candidates for therapeutic development for the treatment of neurodegenerative disease.

Potential barriers to the removal of Norplant among family planning clinic patients

OBJECTIVES

This study examined the prevalence and effects of potential barriers to removal of levonorgestrel implants (Norplant) among low-income women.

METHODS

A sample of 687 women who received Norplant at hospital-based family planning clinics were interviewed before Norplant insertion and 6 months after Norplant insertion (or at Norplant removal if removal occurred earlier). Those who continued to use Norplant were reinterviewed at 2 years or at removal.

RESULTS

In a multivariate analysis, only 1 of the 4 potential barriers--cost--significantly impeded Norplant discontinuation.

CONCLUSIONS

Family planning clinics need to make clear that they follow a policy of Norplant removal on demand, regardless of the patient's ability to pay.

Assessment of intubating conditions in adults after induction with propofol and varying doses of remifentanil

We have assessed intubating conditions in three groups of 60 ASA I or II patients after induction of anaesthesia with propofol 2 mg kg-1 and remifentanil 0.5, 1.0 or 2.0 micrograms kg-1. Tracheal intubation was graded according to ease of laryn-goscopy, position of the vocal cords, coughing, jaw relaxation and movement of the limbs. Intubation was successful in 80%, 90% and 100% of patients after remifentanil 0.5, 1.0 or 2.0 micrograms kg-1, respectively. Overall intubating conditions were regarded as acceptable in 20%, 50% and 80% of patients, respectively. All three groups had a decrease in arterial pressure after induction but there was no difference between groups. The decrease in arterial pressure was not regarded as clinically significant. Intubating conditions were best after induction with remifentanil 2 micrograms kg and propofol 2 mg kg-1.

Rheumatoid factor specificity of a VH3-encoded antibody is dependent on the heavy chain CDR3 region and is independent of protein A binding

Rheumatoid factors (RF) recognize conformational determinants located within the Fc portion of IgG. By analyzing a panel of monoclonal rheumatoid arthritis (RA)-derived RFs, we previously demonstrated that the somatically generated light chain complementarity-determining region 3 (CDR3) contributes to RF specificity. We have now generated a panel of heavy chain mutants of the B'20 Ab, a high affinity RA-derived IgM RF. B'20 also binds avidly to protein A and weakly to ssDNA and tetanus toxoid. B9601, a RF negative Ab that is highly homologous to B'20 but does not bind any of the Ags tested, and RC1, a low affinity polyreactive RF, were used to generate heavy chain mutants with framework (FR) and CDR switches. The mutated heavy chains were cotransfected into a myeloma cell line with the germline counterpart of the B'20 light chain, and the expressed Ig tested for antigenic specificity. We show that both RF specificity and polyreactivity of B'20 is dependent on its unique heavy chain CDR3 region. Replacement with a B9601 CDR3 shortened to the same length as the B'20 CDR3, and with only 5 amino acid differences, did not restore Fc binding. Conversely, absence of protein A binding of B9601 is due to the presence of a serine residue at position 82a in the B9601 heavy chain FR3 region. Together, our data suggest that Ig gene recombination events can generate B cells with autoantibody specificities in the preimmune repertoire. Abnormal release, activation, expansion, or mutation of such cells might all contribute to the generation of a high titer RF response in patients with RA.

The identification of secreted heat shock 60 -like protein from rat glial cells and a human neuroblastoma cell line

The intracellular stress-induced proteins provide protection against toxic insults. Here, a 60,000-Da heat shock 60 (hsp60)-like protein was detected, with five different antibodies, in conditioned media derived from rat cortical astrocytes and a human neuroblastoma cell line. Extracellular neuroblastoma hsp60-like immunoreactivity was increased 3-fold in the presence of the neuropeptide vasoactive intestinal peptide (VIP) and was augmented 2-fold after temperature elevation. Intracellular hsp60 immunoreactivity was reduced 2-3-fold in the presence of VIP; this reduction was attenuated in the presence of brefeldin A, an inhibitor of protein secretion. In contrast, the activity of lactate dehydrogenase (LDH), an intracellular marker, did not change in the presence of VIP. Essentially no extracellular LDH activity was detected, indicating no cellular damage. A novel aspect for stress proteins having extracellular protective roles is suggested.

Oral tolerization to adenoviral proteins permits repeated adenovirus-mediated gene therapy in rats with pre-existing immunity to adenoviruses

Exposure to wild-type adenoviruses is common in humans and results in immune response against adenoviruses. The pre-existing antibodies and a strong secondary humoral and cellular immune response would interfere with gene transfer using recombinant adenoviral vectors. To test whether the secondary immune response can be abrogated by oral tolerization to adenoviral antigens, we immunized bilirubin-UDP-glucuronosyltransferase (BUGT)-deficient jaundiced Gunn rats with a recombinant adenovirus (5 x 10(9) pfu/rat) expressing the human UDP-glucouronosyltransferase (BUGT1) gene (Ad-hBUGT). Transgene expression was shown by reduction of mean serum bilirubin levels from 7.0 mg/dL to 2.3 mg/dL in 14 days, which then increased gradually to pretreatment levels in 6 weeks. All recipients developed antibodies (1:2[10]) and cytotoxic lymphocytes against the adenovirus. For oral tolerization, we administered to the immunized rats protein extracts of a recombinant adenovirus type 5 (1-1.5 mg/day) via duodenostomy tubes 10 to 40 days after the initial virus injection; control rats received bovine serum albumin. In rats fed adenoviral proteins and the BSA-fed controls, the antibody titers decreased to 1:2(7) and 1:2(9), respectively, in 70 days. Lymphocytes from the tolerized rats expressed TGF-beta1 upon exposure to antigen-presenting cells primed with adenoviral antigens, whereas IFN-gamma expression was undetectable. In contrast, lymphocytes from the BSA-treated control rats expressed IFN-gamma but not transforming growth factor beta1 (TGF-beta1). Seventy days after the first injection in the orally tolerized rats, but not in the controls, a second Ad-hBUGT injection caused human BUGT1 expression again, reducing serum bilirubin levels to those observed after the first injection. In the tolerized rats, serum antibody titers and anti-adenoviral cytotoxic lymphocyte activities continued to decline despite the second injection, whereas the antibody levels were boosted in the non-tolerized group. This results show that by preventing the secondary booster response, oral tolerization permits repeated adenovirus-directed gene transfer despite the presence of a residual antibody titer from a previous adenoviral exposure.

Cytokine gene therapy or infusion as treatment for solid human cancer

In the induction of tissue-directed immune responses, cytokines tend to be released within the affected tissues. We used two strategies to expose tumor tissues to continuous high levels of cytokines: First, a vaccinia interleukin (IL)2 recombinant was injected directly intratumorally 3-weekly at 10(7) pfus/dose in six patients with the solid tumor malignant mesothelioma (MM). No virus excretion was detectable. At each cycle vaccinia-IL-2 mRNA (SQ [semi-quantitative] reverse transcription polymerase chain reaction) was maximal 24-72 h following injection reduced at 8 days and faded by 21 days. No tumor regression occurred. Second, based on the success of granulocyte macrophage colony-stimulating factor (GM-CSF) in gene transfer experiments, we conducted a study using continuous intratumoral GM-CSF infusion in eight patients with MM using a portable pump at doses of 10 micro/cg/24 h over 8 weeks. Systemic neutrophil agglutination and local catheter-related difficulties occurred. Two patients demonstrated tumor necrosis, one of whom had a marked progressive mononuclear cell infiltration of the tumor associated with a partial response (>50% reduction in tumor area). Murine studies using our MM model in CBA and BALB/C mice have demonstrated that B7-1 and allo-class I transfections induce strong tumor-specific cytotoxic T lymphocyte responses: GM-CSF, IL-12, and IL-2 induced mixed nonspecific plus specific responses, whereas B7-2 and class II transfections were not effective. We conclude that increased intratumoral cytokine concentrations can be generated using both gene transfer and cytokine infusion approaches; however, both have their limitations and, at this stage, have not produced dramatic antitumor effects in humans.

Protection against developmental deficiencies by a lipophilic VIP analogue

Stearyl-Nle-VIP (SNV) is a novel agonist of vasoactive intestinal peptide (VIP) exhibiting a 100-fold greater potency than the parent molecule and specificity for a receptor associated with neuronal survival. Here, the developmental and protective effects of SNV were investigated in vivo using two models of developmental retardation, hypoxia and cholinergic blockade. In both cases chronic administration of SNV during development provided protective effects. Water maze experiments on the weaned animals have demonstrated a prophylactic action for SNV and enhancement of spatial memory in animals exposed to a cholinotoxin. SNV may act by providing neuroprotection, thereby improving cognitive functions. This work is dedicated to Prof. R.J. Wurtman whose inspiration and leadership in the field of neuroscience and cognition is beyond comparison.

Activity-dependent neurotrophic factor: structure-activity relationships of femtomolar-acting peptides

Activity-dependent neurotrophic factor (ADNF) is a glia-derived protein that is neuroprotective at femtomolar concentrations. A 14-amino acid peptide of ADNF (ADNF-14) has been reported that protects cultured neurons from multiple neurotoxins. Structure-activity relationships of peptides related to ADNF-14 now have been determined. A 9-amino acid core peptide (ADNF-9) has been identified that has greater potency and a broader effective concentration range (10(-16) to 10(-13) M) than ADNF or ADNF-14 in preventing cell death associated with tetrodotoxin treatment of cerebral cortical cultures. Deletions or conservative amino acid substitutions to ADNF-9 resulted in reduced potency, narrower effective concentration range and/or decreased efficacy. Removal of the N-terminal serine or the COOH-terminal isoleucine-proline-alanine from ADNF-9 produced a significant reduction in survival-promoting activity. Comparative studies of ADNF-9 action in mixed (glia plus neurons) vs. glia-depleted neuronal cultures indicated that ADNF-9 can act directly on neurons, although the potency of the peptide was 10,000-fold greater in mixed cultures. Kinetic studies showed that exposure to ADNF-9 for only 2 hr was sufficient to produce a 4-day protection against the cell-killing action of tetrodotoxin. Treatment with bafilomycin A1 (an inhibitor of receptor-mediated endocytosis) for 2 hr prevented the ADNF- and ADNF-9-mediated neuroprotection. ADNF-9, like ADNF-14, was neuroprotective against N-methyl-D-aspartate and the beta-amyloid peptide (amino acids 25-35), and had a much broader range of effective concentrations than ADNF-14. These studies identify ADNF-9 as an attractive lead compound for the development of therapeutic agents against neurodegenerative diseases.

Depressive symptoms and Norplant contraceptive implants

Women enrolled in a multicenter prospective study were evaluated to identify any possible relationship between depressive symptoms and the use of contraceptive implants. Women choosing Norplant implants (n = 910) were evaluated before starting this contraceptive and were reinterviewed at 6 months and 2 years. Women who continued the method had lower depressive symptom scores before initiating Norplant implants than did the women who discontinued the method or who were lost to follow up. Among the continuing Norplant implant users, the mean scores were similar before starting Norplant and at 6 months (7.9 vs 7.7). The strongest overall predictor of the depressive symptom score was relationship satisfaction. At 24 months, the subgroup of continuing users with decreased relationship satisfaction had an increase in depressive symptom score, but those with stable or improved relationships had stable depressive symptom scores. The subjects with the highest (i.e., worst) scores at enrollment demonstrated improved scores during follow-up. These results are reassuring for women who are concerned that Norplant use may adversely affect their mood.

Depressive symptoms and Depo-Provera

Women enrolled in a multicenter prospective study were evaluated to identify any possible relationship between depressive symptoms and the use of contraceptives. Women choosing Depo-Provera (n = 495) were evaluated before starting these contraceptives and were reinterviewed 1 year later. Women who continued the method had lower depressive symptom scores at baseline than did the women who discontinued the method or who were lost to follow-up. Among the continuing Depo-Provera users, the depressive symptom scores improved slightly at 1 year (7.4 vs 6.7). Those subjects with the highest (i.e., worst) scores at enrollment demonstrated improved scores at follow-up.