Oxidative metabolism in cultured fibroblasts derived from sporadic Alzheimer's disease (AD) patients

Fibroblasts from Alzheimer's disease (AD) patients displayed decreased cytochrome c oxidase (complex IV) activity (P < 0.05). The basal oxygen consumption rate (QO2) and the response to an uncoupler of oxidative phosphorylation did not differ between AD and control fibroblasts. The QO2 of AD fibroblasts was more susceptible (P < 0.05) to inhibition by azide in the range 0.5-5 mM. The basal intracellular pH (pHi) in AD fibroblasts was significantly more acidic than in control ones. The results support the hypothesis that subtle dysfunctions of oxidative energy-producing processes are present in fibroblasts from sporadic AD patients. The alterations observed scantly influence the fibroblasts functioning even in stressful conditions; however in tissues, such as the brain, that rely heavily on oxidative metabolism for their function, similar alterations may trigger molecular mechanisms leading to cell damage.

Inhibition of murine leukaemia virus retrotranscription by the intracellular expression of a phage-derived anti-reverse transcriptase antibody fragment

The intracellular targeting of recombinant antibodies is an experimental strategy to interfere with the function of selected molecules that is being utilized in a variety of different systems for research and medical applications. Since recombinant antibodies are increasingly being derived from phage display libraries, we have exploited phage technology to isolate, from a large combinatorial library, human antibody fragments directed against human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). We describe in this paper the in vitro and in vivo properties of a neutralizing anti-RT antibody fragment. We demonstrate that the heavy chain domain (VH-CH1) of the phage-derived antibody is able to inhibit the retroviral enzyme, in that it neutralizes the RNA-dependent DNA polymerase activity of HIV-1 RT. The VH-CH1 antibody fragment also neutralizes the activity of RT of drug-resistant HIV-1 mutants as well as that of murine retrovirus RT. To confirm the broad reactivity of the synthetic antibody fragment, we have assessed the ability of the intracellularly expressed VH-CH1 protein to interfere with murine retroviral infection. To this end, we developed an in vivo selection procedure based on the antibody-mediated resistance to a cytotoxic retrovirus and used this selection procedure to rescue, from a heterogeneous population, cells expressing the VH-CH1 antibody fragment. We finally demonstrate that the intracellular expression of the recombinant heavy chain antibody fragment leads to an efficient inhibition of viral retrotranscription by murine-based retrovirus.

Rescue of a neutralizing anti-viral antibody fragment from an intracellular polyclonal repertoire expressed in mammalian cells

The intracellular expression of recombinant antibodies in mammalian cells is an experimental strategy to inhibit in vivo the function of selected molecules. However, one limitation of this technology is represented by the unpredictable behaviour of antibodies, under conditions of intracellular expression. For this reason, it would be desirable to exploit intracellular expression of antibodies to select or rescue more efficient ones from a polyclonal mixture. In this work we have successfully explored this possibility by rescuing a neutralizing anti-viral antibody fragment from an intracellularly expressed anti-reverse transcriptase polyclonal repertoire.

Posttransplantation cutaneous B-cell lymphoma with monoclonal Epstein-Barr virus infection, responding to acyclovir and reduction in immunosuppression

Posttransplantation lymphoproliferative disorders (PTLDs) represent an important complication of solid organ transplantation. The main causative factor of PTLDs seems to be the intensity and type of immunosuppressive therapy and the frequent occurrence of Epstein-Barr virus infection. PTLDs that are disseminated at diagnosis or present late after transplantation generally share an unfavorable prognosis and are unlikely to regress in response to reduction in immunosuppressive therapy. We describe a case of cutaneous B-cell lymphoma occurring 4 years after heart transplantation in which molecular analysis revealed a monoclonal pattern of Epstein-Barr virus infection and immunoglobulin gene rearrangement. In spite of its monoclonal nature and late occurrence, the lymphomatous lesions regressed completely after antiviral treatment and a reduction in immunosuppressive therapy.

NGF antibodies impair long-term depression at the mossy fibre-CA3 synapse in the developing hippocampus

Nerve growth factor (NGF) and other neurotrophins are proteins involved in neuronal survival and differentiation. Much experimental evidence is now drawing attention into a role of neurotrophins in activity-dependent synaptic plasticity processes. We now show that slices from rats chronically deprived of NGF, by intraventricular injection of alpha D11 hybridoma cells, which produce monoclonal antibodies against NGF, display a reduced probability of induction of long-term depression at the mossy fibre-CA3 synapse.

An integrated vector system for the eukaryotic expression of antibodies or their fragments after selection from phage display libraries

Phage display is now an established method to select antibody fragments specific for a wide range of diverse antigens. In particular, isolation of human monoclonal antibodies has become a reality and for most purposes bacterial expression of the selected recombinant antibody fragments is sufficient. However, there are some cases where the expression of complete human immunoglobulin in mammalian cells is, if not essential, at least desirable. For this reason we have designed and constructed a set of mammalian expression vectors which permit facile and rapid cloning of antibody genes for both transient and stable expression in mammalian cells. Immunoglobulin genes may be cloned into these expression vectors as V regions or as Fabs for expression as either complete antibodies or as Fab fragments, using restriction sites which are rare in human V genes. All the important elements in the vectors--promoter, leader sequence, constant domains and selectable markers--are flanked by unique restriction sites, allowing simple substitution of elements. The vectors have been evaluated using the variable regions from the neutralizing anti-nerve growth factor (NGF) antibody, alphaD11, and the V regions from 2E10, a scFv selected from a scFv phagemid library.

Targeting vectors for intracellular immunisation

We define intracellular immunization as the inhibition or inactivation of the function of a molecule by the ectopic intracellular expression of antibody binding domains which recognise the molecule. Such recombinant antibodies can be directed to different compartments of eukaryotic cells by means of previously defined targeting signals, thus permiting the study of any molecule in any cellular compartment for which an antibody is available. For this purpose, we have created a set of vectors based on the VHExpress vector described [Persic, L., Roberts, A., Wilton, J., Cattaneo, A., Bradbury, A. and Hoogenboom, H.R. (1997) An integrated vector system for the eukaryotic expression of antibodies or their fragments after selection from phage display libraries. Gene 187, 000-000], which has been modified to express scFvs (single chain fragments) linked to specific targeting signals. These permit the localisation of scFvs to different intracellular compartments: the endoplasmic reticulum (scFvE-er), the nucleus (scFvE-nuclear), the mitochondria (scFvE-mit), the cytoplasm (scFvE-cyto), and as secreted proteins (scFvE-sec). The function of these vectors has been assessed by the immunofluorescence of COS cells transiently transfected with constructs containing the alphaD11 scFv.

Fibrogenic cytokines in vulvar lichen sclerosus. An immunohistochemical study

OBJECTIVE

To evaluate the expression of fibrogenic cytokines in lichen sclerosus (LS) infiltrate as compared with lichen planus (LP) infiltrate.

STUDY DESIGN

Eight cases of vulvar LS (early stage, n = 3; well developed or old, n = 5) and 4 of vulvar LP were studied. Monoclonal antibodies directed against some of the major fibrogenic cytokines (IL-4, TGF-beta, IL-6) and against IFN-gamma, which inhibits collagen synthesis, were used per the alkaline phosphatase/anti-alkaline phosphatase technique on frozen sections.

RESULTS

Staining for IL-4 revealed higher expression of fibrogenic cytokines (more than 50% infiltrating cells) in the LS infiltrate, mainly in early lesions, than in LP. Conversely, staining for IFN-gamma in LS was poor (less than 10% infiltrating cells), while strong positivity (more than 60% infiltrating cells) was found in LP. Staining for TGF-beta, a mediator of fibrosis in scleroderma, was similar in both LS and LP dermis.

CONCLUSION

This study showed the immunohistochemical expression of fibrogenic cytokines in vulvar LS, with a different pattern as compared to that of LP. It is conceivable that dermal infiltrating cells actively participate, via cytokine production, in the pathogenesis of fibrosis in LS.

Neurotrophin-3 promotes the survival of oligodendrocyte precursors in embryonic hippocampal cultures under chemically defined conditions

embryonic rat hippocampal cells were cultured in basal medium with or without addition of the neurotrophin NT-3. After culturing in these extreme conditions, the effects of NT-3 on the neuronal and on the glial components were assessed. Neurons survived even in the absence of NT-3 but failed to reach terminal differentiation. On the other hand, NT-3 promoted the survival but not the proliferation and/or the differentiation of oligodendrocytes precursors present in the same culture, an effect that was reversed by the addition of neutralizing antibodies against NT-3. Type I or II astrocytes were not affected by NT-3. These results reinforce the role for NT-3 in oligodendrocyte lineage development and allow to dissect the roles of this neurotrophin in survival and in proliferation/differentiation of oligodendrocytes.

A critical period in the sensitivity of basal forebrain cholinergic neurones to NGF deprivation

Cholinergic neurones of basal forebrain (BF) express receptors for nerve growth factor (NGF) and are sensitive to NGF. In many CNS structures, including the BF region, the expression of NGF and its receptors is developmentally regulated. To test whether BF neurones depend on NGF during restricted time windows of postnatal development, we antagonized endogenous NGF by implanting, in the lateral ventricle of the rat, hybridoma cells producing blocking antibodies specific for NGF. Implants were performed at postnatal day 2 (P2), P8 and P15. BF cholinergic neurones were drastically reduced in number only when endogenous NGF was antagonized during the first postnatal week. We conclude that BF cholinergic neurones are sensitive to NGF deprivation only during early postnatal development.

Subcellular localisation of neurotrophins and neurotrophin receptors: implications for synaptic plasticity

A growing body of recent evidence indicate that neurotrophins can act as mediators of neuronal plasticity. In the context of a more detailed, comprehensive understanding of the function of neurotrophins it is essential to characterize where neurotrophins are synthesised and stored and from where they are released. Here we present evidence that the mRNAs for NGF, trkB and BDNF but not trkA are localised in the dendrites of rat neurons, thus implying that neurotrophins and their receptors can be synthesised at locations close to their sites of function, with particular regard to the dendritic synapses. The significance of this finding and its possible implications for synaptic plasticity are discussed within the theoretical framework of the synapse-specific control of individual synapses of a given neuron.

The performance of SAPS II in a cohort of patients admitted to 99 Italian ICUs: results from GiViTI. Gruppo Italiano per la Valutazione degli interventi in Terapia Intensiva

OBJECTIVE

To assess the validity of SAPS II (new Simplified Acute Physiology Score) in a cohort of patients admitted to a large sample of Italian intensive care units (ICU).

DESIGN AND SETTING

The ability of the SAPS II scoring system to predict the probability of hospital mortality was assessed with calibration and discrimination measures obtained using published coefficients. A new logistic regression equation was then developed and further formal calibration and discrimination measures were estimated for the customized model.

PATIENTS

From the 2202 consecutive patients recruited during a 1-month period in 99 ICUs, a total of 1393 patients were included in this validation study.

RESULTS

When the parameters based on the standard model were applied, the expected probability of mortality did not fit those actually observed in the cohort (p < 0.001), although it showed satisfactory discrimination (area under the receiver operating characteristic curve = 0.80). Such lack of fit yields an overall under prediction of mortality (observed/expected ratio = 1.14) that reflects a uniform pattern across a preselected set of subgroups. Customization allowed new mortality estimates to be calculated, with satisfactory calibration (p = 0.82) and a more uniform pattern across subgroups.

CONCLUSIONS

SAPS II maintained its validity in an independent sample of patients recruited in a large network of Italian ICUs only after appropriate adaptation (first-level customization). Whether the determinants of this relatively poor performance are related to differences in unmeasured case-mix, methods of application, or quality of care delivered is a matter for discussion that cannot be solved with the data presently available. However, these findings suggest that caution is warranted before implementing the standard SAPS II scoring system parameters outside formal research projects.

Human recombinant antibody fragments neutralizing human immunodeficiency virus type 1 reverse transcriptase provide an experimental basis for the structural classification of the DNA polymerase family

We describe in this paper the binding and biochemical properties of two human antibody fragments directed against the human immunodeficiency virus type 1 reverse transcriptase (RT). These fragments were isolated from a synthetic combinatorial library of human Fab antibody fragments displayed on the surface of filamentous phage. The antibody fragments were selected by using recombinant heterodimeric human immunodeficiency virus type 1 RT purified from insect cells as a solid-phase selector. This procedure led to the isolation of two antibody fragments that completely neutralize the RNA-dependent DNA polymerase activity of RT at nanomolar concentrations. Both antibody fragments bind only to the enzymatically active form of the RT. The inhibitory activity of the anti-RT antibody fragments is competitive with respect to the template primer. The antibody fragments also neutralize the activities of RTs from avian and murine retroviruses and of DNA polymerases of prokaryotic origin as well as human DNA polymerase alpha. Thus, the antibody fragments selected and characterized in this study appear to recognize a structural fold that is common to the different DNA polymerases and necessary for their activity. The results provide an immunological experimental basis for a purely structural and evolutionary classification of the polymerase family.

[Principles of the clinical evaluation of the vulvar region]

The clinical examination of the vulva, using an articulated method, should form part of the routine gynecological examination thus enabling both the correct diagnosis and treatment of numerous alterations and the prevention and early diagnosis of VIN and invasive neoplasias. A correct evaluation should include basic anamnestic data, a list of symptoms localised in the vulva region, a careful inspection and palpation. The successive aim is to identify the main clinical aspects of the lesion which can be summarized as changes of colour, presence of swellings on surface and loss of substance. The critical evaluation of lesions should allow critical evaluation of lesions should allow the gynecologist to formulate a diagnosis to propose to the pathologist. In this way the collaboration between clinician and pathologist can contribute to progress in the diagnosis and treatment of vulvar diseases.

Dexamethasone adjunctive therapy for bacterial meningitis in children: a retrospective study in Brazil

The clinical records of 87 children with bacterial meningitis treated with antibiotics (group 1) and of 92 treated with antibiotics plus dexamethasone (group 2), admitted to the Instituto Materno Infantil de Pernambuco, Recife, Brazil over 2 consecutive years (1991 and 1992), were analysed. There were no significant differences between treatment groups regarding characteristics on admission except that group 1 were younger. The overall case fatality rate was 19%, with 14% in group 2 and 24% in group 1 (p = 0.09). Rate of discharge without sequelae was 70% in the steroid-treated children and 56% in children treated with antibiotics alone (p = 0.07). Among children aged 6-59 months, those treated with dexamethasone compared with those treated with antibiotics alone had a better case fatality rate (11% vs 25%; p = 0.05) and a better rate of discharge without sequelae (73% vs 52%; p = 0.02). Among the cases with a CSF culture positive for Haemophilus influenzae, 77% were discharged without sequelae in group 2 compared with 51% in group 1 (p = 0.03). The addition of dexamethasone to standard antibiotic treatment improves the outcome of children between 6 and 59 months of age admitted to hospital with a diagnosis of bacterial meningitis.

[Evaluation of activity in intensive care. A comparison of administrative and epidemiologic data]

This paper reports on results of a formal comparison of data excerpted from 3 different data sources regarding patients cared for in Italian Intensive Care Units (ICU) in 1992. The analysis was carried out in order to assess whether the administrative data routinely collected for reimbursement and policy issues are valid when compared with data from epidemiologic studies. First, using data from the Central Service for Health Planning (SCPS) a general description of the whole national scenario is shown. All the Italian data from 265 Italian hospitals having at least one ICU were analyzed. In these hospitals there were 2,357 ICU beds (4.3 beds/1000 inhabitants, with large regional variability). About 100,000 cases were identified (1% of all the hospital admissions received ICU care at some moment during the stay), with an overall hospital mortality rate of 17%. This estimate was largely different from those obtained from GiViTI data base (5100 patients from a national sample of 114 ICUs), where mortality rates were always higher (25 and 30%, for ICU and hospital mortality). Second, a more detailed analyses and comparison was carried out in the subsample of cases admitted in the Hospitals of the Regione Lombardia. In this case, beside the data from SCPS (No = 20580) and from GiViTI (No = 1121), the Regional data-base formed by all the discharge from 41 hospitals having at least one ICU were available (NO = 16674), allowing a formal comparison between estimates obtained from 3 different sources. In this sub-sample, although administrative data showed a good capability and satisfactory accuracy to describe the volume and socio-demographic and clinical characteristics of the cases when compared with GiViTI estimates, still a systematic underestimate of the overall ICU and hospital mortality was present. Moreover, an unexpected high rate of cases were apparently discharged alive from ICU (16.5 versus 32.6% in GiViTI). Tentative explanations and implications of these phenomena are discussed in the text. Finally, in the Lombardia sub-sample a formal description of the case-mix using the Diagnosis Related Group (DRG) system was carried out in order to identify strengths and limitations of this approach when adopted in the ICU setting. Overall, when data are analyzed according to the kind of Major Diagnostic Category (MDC), 75% of all cases were concentrated in 5 alone, with very peculiar concentration in some specific categories. For example, 45% of all the hospital admissions related to the multiple trauma were actually admitted in the ICU setting. At DRG level, fifty of the 493 DRGs available explained 65% of all the cases, showing an unexpected capability of this system to detect the ICU case-mix. The most represented surgical DRG was the number 107 (Coronary Arterial Bypass Graft, without catheterization) and the corresponding medical was the 28 (Cerebro Vascular Accident, excluding TIA).

Testosterone maintenance therapy. Effects on vulvar lichen sclerosus treated with clobetasol propionate

OBJECTIVE

To evaluate the possible effects of topical testosterone as maintenance therapy after clobetasol propionate treatment.

STUDY DESIGN

Thirty-two patients with biopsy-proven vulvar lichen sclerosus (LS), after 24 weeks of treatment with 0.05% clobetasol propionate cream, were randomly distributed into two groups of 16 each and treated for a further length of time (24 weeks) with testosterone 2% ointment or a cream-based preparation (placebo). The patients were examined before and after treatment for symptoms, gross aspects and histologic features.

RESULTS

With clobetasol propionate all patients had a marked improvement (P < .001) in both clinical and histologic parameters. After clobetasol propionate therapy, the 16 testosterone-treated patients had significant worsening of their symptoms (P < .05%) and no evident changes in gross aspects (P = NS). The placebo-treated group had good symptomatic control of their disease, with no significant changes in symptoms or gross aspects (P = NS).

CONCLUSION

After the good results obtained with clobetasol propionate, treatment with testosterone appeared to have a negative effect, while a regularly provided emollient cream was useful in symptom control.

Squamous cell carcinoma arising in vulval lichen sclerosus: a longitudinal cohort study

Histological changes of lichen sclerosus (LS)--a chronic inflammatory disease--are frequently found in association with squamous cell carcinoma (SCC) of the vulva, suggesting that women with this disorder are at increased risk. However, follow-up studies have been less convincing, showing that the vast majority of these patients do not go on to develop cancer. In this study, a series of 211 women affected by histologically demonstrated vulval LS were treated with topical therapy (testosterone, clobetasol) and followed prospectively by repetitive vulval examination. Three patients developed SCC of the vulva (two invasive, one in situ) at the sites affected by LS during an average follow-up period of 1 year and 8 months. Compared with the reference population, the number of cases of invasive SCC detected significantly exceeded the number estimated to occur in a comparable age-matched group. The standardized incidence rate of vulval SCC in the LS cohort was 317 (95% CI 35.7-1146.2). Cumulative risk was 14.8% (0.06% in the general female population), with a relative risk of 246.6. In conclusion, these data support the view that LS is a precursor of SCC, although characterized by slight tendency to evolve to carcinoma. Medical treatment of LS, although useful in the control of severity of disease, did not seem to be able to prevent the evolution to malignancy.

Fetal heart screening in low-risk pregnancies

The aim of this study was to assess whether a screening program for fetal cardiac malformations is justified in a low-risk population, and which factors influence its accuracy. The fetal heart was evaluated in 7024 pregnant women at 20-22 weeks, and evaluation was repeated at a more advanced gestational age in 9% of cases. Cardiological follow-up was continued postnatally until 2 years of age. The overall prevalence of cardiac anomaly was 0.93%. The incidences of major and minor defects were 0.44% and 0.48%, respectively. There were 23 true positives (0.33%): in 20 cases, the diagnosis was made in the second trimester, and 13 women (65%) chose termination of pregnancy. Seventeen of the 20 cases identified in the second trimester were serious malformations. There were 42 false negatives (0.60%). Of these, 12 had signs of cardiac dysfunction at birth or within the 1st month of life, and three of them died as a result of their cardiac anomaly. There were eight false positives (0.11%), all of a minor type. Six abnormal karyotypes, out of a total of 21 performed in the true-positive group (28.5%), were found. In addition, five of the 42 newborns in the false-negative group had trisomy 21. The overall sensitivity was 35.4%, and 61.3% for major defects. The accuracy in two distinct periods was estimated because the level of experience of the operators was different: sensitivity was 45.2% in period 1 (1986-88) (77.8% for major defects) and 26.5% in period 2 (1989-92) (52.9% for major defects). We conclude that a fetal heart screening program in the obstetric population is justified. It defines a high-risk group for karyotyping, allows planning of delivery in a tertiary center or the choice of terminating the pregnancy for the parents and appears to have a positive cost-benefit ratio. A crucial factor is the level of training and experience of the operators, who need specific teaching support.

Production of type-1 and type-2 cytokines by peripheral blood mononuclear cells of psoriatic patients

We investigated the function of peripheral blood mononuclear cells (PBMC) in 16 patients with active psoriasis, in 15 patients with static psoriasis and in 27 healthy volunteers, by examining in vitro proliferation and antigen- and mitogen-stimulated production of interleukin-2 (IL-2) and IL-4. Plasma levels of the neuropeptide substance P were also determined. Defective alloantigen (ALLO)- and phytohaemagglutinin (PHA)-stimulated IL-2 production was detected in 42% and in 45% of psoriatic patients, respectively. The number of defective IL-2 responders was higher in static (60%) than in active (25%) psoriasis. The reduction of IL-2 responses in the former group was associated with an increase of IL-4 production. Thus PBMC of 66% of patients with static psoriasis but none of the patients with active psoriasis produced elevated amounts of PHA-stimulated IL-4. Variations of plasma substance P levels followed the same pattern of IL-4, being higher in static than in active psoriasis. These observations suggest a co-ordinated action of IL-4 and substance P as modulators of the clinical course of psoriasis. Our data show a possible correlation between the clinical evolution of psoriasis and the production of type-1 and type-2 cytokines, suggesting that the former may have a prominent role in the activation of psoriasis, while the latter may play a protective role.

Redox state of single chain Fv fragments targeted to the endoplasmic reticulum, cytosol and mitochondria

In this paper we have engineered the targeting of ScFv fragments to mitochondria and demonstrated that this can occur efficiently. This extends the range of subcellular compartments where antibody domains can be targeted in order to interfere with the action of the corresponding antigen. Moreover, we have compared the redox state of ScFv fragments targeted to the secretory compartment, the cytosol and the mitochondria, and demonstrated that cysteine residues in ScFv targeted to the secretory compartments and to the mitochondria are oxidized. On the contrary, cytosolic antibody domains are expressed in a reduced state, which is probably the reason for their lower expression levels. These pitfalls, however, do not prevent their successful utilization for intracellular immunization.

Quick purification of recombinant human truncated tau proteins for immunoanalysis

A simple and rapid purification method is described which exploits the heat stability of human tau (tau) protein to prepare truncated forms of this protein derived from bacteria. Bacterial cells expressing tau fragments were pelleted, resuspended in phosphate buffered saline and boiled for 5 min. After centrifugation the supernatant containing thermostable tau was filtered (0.45 microns) and used for immunoanalysis with monoclonal antibodies. The purified tau fragments exhibited identical antigenic properties as fragments isolated by a conventional procedure, based on ion exchange chromatography on phosphocellulose. In contrast to the conventional approach, our method is less complicated, cheaper and significantly reduces the time required for isolation of the recombinant tau fragments.

Massive vulvar edema in ovarian hyperstimulation syndrome. A case report

BACKGROUND

Bilateral vulvar edema associated with severe ovarian hyperstimulation syndrome is described for the first time.

CASE

A 28-year-old woman underwent gonadotropin-releasing hormone analogue and gonadotropin treatment for in vitro fertilization and embryo transfer. On day 18 of the cycle, the patient reported mild abdominal discomfort that became severe during the following four days. One the 22nd day of the cycle, bilateral ovarian enlargement and ascites were present. The vulva showed massive edema and fissures. Ovarian hyperstimulation syndrome (OHSS) therapy consisted of human albumin, lactated Ringer's solution and heparin. The vulvar edema was treated with topical hydrocortisone ointment, ice packs and topical gentamycin twice a day. After one week of treatment, the vulva was normal.

CONCLUSION

We think that the vulvar edema in this case was the result of decreased oncotic pressure and increased hydrostatic pressure, as occur during OHSS.

Neuroantibodies: ectopic expression of a recombinant anti-substance P antibody in the central nervous system of transgenic mice

Recombinant antibodies are efficiently secreted by cells of the nervous system. Thus, their local expression in the CNS of transgenic mice could be used to perturb the function of the corresponding antigen. As a first application of this approach, we have generated transgenic mice that express antibodies against the neuropeptide substance P, under the transcriptional control of the promoter of the neuronal gene vgf. The transgenic antibodies are expressed in a tissue-specific and developmentally regulated manner and are effective in competing with the endogenous substance P, as demonstrated by a marked inhibition of neurogenic inflammation and by motor deficits. This phenotypic knockout approach may provide a complementary alternative to gene knockout by homologous recombination.

The use of phage display in neurobiology

Phage display is a new technique that is used extensively in molecular biology to study protein-protein interaction, receptor- and antibody-binding sites, to produce monoclonal antibodies against diverse antigens, some of which are too well conserved for the production of monoclonal antibodies by traditional means, and to improve or modify the affinity of proteins for their binding partners. This technique could have many applications in neurobiology. This review describes the background to the technique, and illustrates a number of possible uses in neurobiology, ranging from the production of antibodies to non-immunogenic proteins and to those that are available as cloned DNA sequences only, to the detailed study of receptor-ligand interaction using either ligands, their receptors or neutralizing antibodies.

Idiopathic vulvodynia. Clinical evaluation of the pain threshold with acetic acid solutions

Idiopathic vulvodynia is vulvar discomfort in which a diagnosis has not yet been established. As in other idiopathic pain syndromes, the involvement of primary afferent fibers (PAFs) has been postulated as playing a role in the pathogenesis and maintenance of idiopathic vulvodynia. Capsaicin induces the release of substance P (SP) by PAFs, producing vasodilation and increasing vascular permeability (neurogenic inflammation). Likewise, it has been shown that acid solutions can stimulate PAFs with the release of SP. To evaluate the pain threshold in women with idiopathic vulvodynia, 10 patients with vulvar pain but without significant vulvar physical changes and 10 asymptomatic controls received topically applied acetic acid solutions with increasing hydrogenionic concentrations (pH 3, 2.5, 2, 1.5, 1.2). Results related to pain threshold and pain time monitoring and intensity were analyzed with Fisher's exact and Wilcoxon's tests, respectively. Our data suggest that in idiopathic vulvodynia the pain threshold for acid solutions is decreased, probably in relation to increased sensitivity of PAFs involved in the transduction of painful signals.

Neurofilament-negative neurones exhibit HVA Ca2+ currents with faster inactivation kinetics

The whole cell configuration of the patch clamp technique was used to study the biophysical and pharmacological properties of voltage activated Ca2+ channel currents on hippocampal neurones cultured in the presence or absence of foetal calf serum. In the presence of serum cells were intensively immunostained with neurofilament (NF) antibodies. In the absence of serum, cells were non-immunoreactive; they were identified as neurones by their ability to generate action potentials. NF negative cells still expressed both high (HVA) and low (LVA) voltage activated Ca2+ channels. However, in comparison to NF positive neurones, HVA Ca2+ currents present in NF negative neurones had a faster inactivation kinetics.

Identifying a putative common binding site shared by substance P receptor and an anti-substance P monoclonal antibody

Substance P G-protein coupled receptor and the antigen recognition site of a monoclonal antibody raised against substance P share a stretch of five contiguous identical amino acids. This observation prompted us to build an atomic model of both the receptor and the antibody and to analyse their common features. In particular, we report here that a pocket of similar size and composition is present in both proteins, strongly suggesting a similarity in the mode of binding of both macromolecules to substance P. From the analysis of our models, the available data on the mode of binding of the antibody to substance P and recent data on substance P receptor mutants, we concluded that the pocket is very likely to be involved in binding of the C-terminal 'message sequence' of the tachykinin. This allowed us to suggest specific site-directed mutants of the receptor which should shed some light on the mechanism of peptide recognition by G-protein coupled receptors.

Evaluation and retraining of adults' cognitive impairment: which role for virtual reality technology?

Immersive virtual reality (IVR) is a technology already developed to assist cognitive psychologists and therapists in their clinical work with brain-damaged patients. The rationale, the software and the hardware of the first application (ARCANA 1) based on affordable technology are discussed here, in order to provide a concrete example of what the authors think may be the role of IVR as a clinical tool. Although prospects are exciting, extensive research is needed to validate this new approach and reveal its limitations and advantages.

Epiphyte size and taxonomy as biological indicators of ecological and toxicological factors in Lake Saint-François (Québec)

To assess the potential of the epiphyton community for monitoring spatial and temporal variations in the environmental quality of freshwater ecosystems, this paper describes the response of epiphytons to ecological and toxicological factors in Lake Saint-François, a fluvial lake of the St. Lawrence River (Québec). First, community descriptions and biotic indices based on size structure and on taxonomic composition were compared to test if size could usefully describe epiphyton response to environmental factors. Secondly, the relative contribution of ecological and toxicological variables in explaining the variation observed in epiphyton was quantified. A size-based approach classified the sites similarly to taxonomic analysis, but a larger portion of variance in size could be explained indicating a stronger relationship with environmental factors. Among both taxonomy and size-based biotic indices, the slope of the normalized size spectra performed best in terms of total explained variance. There were strong interactions between toxicological and ecological variables. These interactions should be considered in the planning and interpretation of biomonitoring studies. In such surveys, samples should be collected at sites with similar ecological characteristics: for example, the same macrophyte type and sediment texture. Interpretation of the data should consider the possible covariance of toxicological and ecological variables.

Nerve growth factor (NGF) uptake and transport following injection in the developing rat visual cortex

Recent investigations have shown that cortical nerve growth factor (NGF) infusions during the critical period inhibit ocular-dominance plasticity in the binocular portion of the rat visual cortex. The mechanisms underlying the effects of NGF on visual cortical plasticity are still unclear. To investigate whether during normal development intracortical and/or extracortical cells possess uptake/transport mechanisms for the neurotrophin, we injected 125I-NGF into the occipital cortex of rats at different postnatal ages. Within the cortex, only a few labelled cells were observed. These cells were confined to the vicinity of the injection site and their number depended on the animal's age at the time of injection. Labelled cells were absent at postnatal day (PD) 10 but could be detected between PD 14 and PD 18. They then decreased in number over the following period and were not detected in adult animals. Outside the cortex, neurons of the lateral geniculate nucleus (LGN) were not observed to take up and retrogradely transport NGF at any age after birth. In contrast, retrogradely labelled neurons were found in the basal forebrain. Labelled cells were first observed here at PD 14 and then increased in number until reaching the adult pattern. Our results show that intrinsic and extrinsic neurons are labelled following intracortical injections of iodinated NGF. In both neuronal populations, the uptake and transport of NGF is present over a period corresponding to the critical period for visual cortical plasticity. These findings suggest that NGF may play a role, both intra and extracortically, in plasticity phenomena.

Antibodies to nerve growth factor (NGF) prolong the sensitive period for monocular deprivation in the rat

Neural plasticity in the visual cortex, as tested by changes in its functional organization induced by monocular deprivation (MD), is present only during a restricted period of postnatal development (critical period). To investigate whether this process of synapse strengthening depends upon NGF, we antagonized endogenous NGF during the critical period by implanting anti-NGF producing cells. Anti-NGF treated and control rats were monocularly deprived after the end of the critical period. In anti-NGF treated but not in control rats MD was still effective. We conclude that antagonism of endogenous NGF prolongs the critical period, possibly by delaying the process of synapse consolidation in the visual cortex.

The use of the RACE method to clone hybridoma cDNA when V region primers fail

The technique of V region PCR to clone antibody V regions from hybridomas has been extensively used. However, in addition to, or even instead of, cloning the V regions with the desired specificity, myeloma cell derived V regions, V regions which are the result of non-productive rearrangements, and also V regions which are productive but which do not recognise the antigen of interest, may be isolated. In this paper we describe a comparison of the use of V region PCR and a modification of the RACE technique to clone the V region of the anti-NGF hybridoma, alpha D11. This hybridoma has heavy and light chain V regions which are refractory to amplification with V region primers, but which are easily amplified using RACE, a PCR based procedure which is independent of the variability within the V regions.

Intracellular immunization with cytosolic recombinant antibodies

We report the application of a strategy to inactivate cellular proteins in vertebrate cells based on the intracellular expression of immunoglobulin genes. We have selected, in this instance, the p21 protein, encoded by the ras proto-oncogene, as a target protein. The variable regions of the neutralizing anti-p21ras monoclonal antibody Y13-259 were cloned in vectors for the expression of either the whole antibody molecule or its single-chain Fv fragment (ScFv) derivative. In order to target the recombinant antibodies to the cytosol, their hydrophobic leader sequence for secretion was mutated or deleted. When these proteins are expressed in the cytosol of Xenopus laevis oocytes they colocalize with the endogenous p21ras protein in the cytoplasmic face of the oocyte plasma membrane, and they markedly inhibit the H1 kinase activity induced by insulin. Moreover, cytosolic anti-p21ras ScFv fragments block the ensuing meiotic maturation. Thus the intracellular expression of both whole antibodies and antibody domains can be used to block a biological function.

Low-affinity nerve growth factor receptor is expressed during testicular morphogenesis and in germ cells at specific stages of spermatogenesis

Nerve growth factor (NGF) is essential for neuronal development and differentiation. Recent reports have shown that its low-affinity receptor (LNGFR) is expressed and developmentally regulated in a broad range of embryonic and adult tissues outside the nervous system, although the functions of the receptor in such tissues remain unknown. Recently, NGF and LNGFR have been detected in adult mouse, rat, and human testis. The results of the present work demonstrate that LNGFR is expressed much before the onset of spermatogenesis in both mouse and rat testis. In situ hybridization shows that the mRNA for LNGFR is expressed in the peritubular cells of the embryonic mouse testis. Immunohistochemical analysis of the rat testis shows LNGFR-expressing cells to be scattered in the intertubular compartment in the embryonic testis, and to become organized in a cellular layer that surrounds myoid cells of the seminiferous tubules during postnatal development. Furthermore, in peripuberal and adult mouse and rat testis we have identified the expression of an abundant and shorter mRNA of 3.2 kb that cross hybridizes to the low-affinity NGF receptor transcript (3.7 kb). This shorter mRNA species, which appears at the beginning of spermatogenesis in the adult, has been identified by in situ hybridization and by Northern blot with RNA isolated from homogeneous populations of meiotic germ cells to be expressed by pachytene spermatocytes and round spermatids. Our results suggest a complex developmental role for LNGFR during testicular morphogenesis and identify the expression, at specific stages of spermatogenesis, of a new germ cell-specific transcript homologous to the receptor RNA.

Vulvar lichen sclerosus. Immunohistologic evaluation before and after therapy

In 20 women with vulvar lichen sclerosus (LS) we analyzed the immunohistologic features of the dermal lymphoid infiltrate and the number of epidermal CD1a+ cells (Langerhans cells). Activated (HLA-Dr+) T cells, associated with CD1a+ accessory cells, were found in the dermis in all cases. The number of CD1a+ epidermal cells was increased, and the cells expressed strong HLA-DR+ staining. These findings suggest activation of the skin immune system in vulvar LS lesions. Conventional 2% testosterone therapy failed to modify the immunohistologic features. Clobetasol, 0.05%, application seemed more effective in down-regulating the skin's immune system activation profile.

Current role of vaccination in preventing acute respiratory infections in children in developing countries

Acute respiratory infections (ARI) cause more than four million childhood deaths each year in developing countries. In addition to standard case management, vaccines have a great potential for reducing these deaths. Immunization against measles and pertussis, already reaching more than 70% of infants in developing countries, contributes to the prevention of more than one million childhood deaths. New conjugate vaccines against Haemophilus influenzae type b, if shown to be effective against pneumonia in developing countries, could reduce acute lower respiratory infection (ALRI) deaths by 4%. A further 10% reduction could be obtained by the availability of an effective conjugate vaccine against Streptococcus pneumoniae. A safe vaccine against respiratory syncytial virus could also prevent 10% of ALRI deaths. The potential role of other bacterial and viral vaccines needs to be clarified.

Monoclonal antibodies to nerve growth factor affect the postnatal development of the visual system

Exogenous supply of nerve growth factor (NGF) prevents the effects of monocular deprivation. This suggests that visual afferents may be competing for an endogenous neurotrophic factor, related to NGF, whose production by postsynaptic cells depends on the activity of afferent fibers. To test the hypothesis that endogenous NGF may play a role in the functional and anatomical development of the rat geniculo cortical system, the physiological action of NGF in the rat visual system was antagonized by using two independent monoclonal antibodies which neutralize NGF (alpha D11 and 4C8). To provide a continuous supply of antibodies during the period of visual cortical plasticity, alpha D11 or 4C8 antibody-producing hybridoma cells were implanted in the lateral ventricle of rats at postnatal day 15. This resulted in dramatic alterations of two of the most important parameters characterizing the functional development of the visual system, namely, visual acuity and binocularity of cortical neurons and in shrinkage of cells in the lateral geniculate nucleus. This demonstrates that the action of endogenous NGF is necessary for the normal functional and anatomical development of the geniculocortical system.

Intracellular expression of anti-p21ras single chain Fv fragments inhibits meiotic maturation of xenopus oocytes

The recombinant variable regions of the monoclonal antibody Y13-259, directed against the p21ras protein, have been engineered for expression as intracellular single chain Fv fragments. The activity of the plasmid was confirmed by in vitro and in vivo translation of mRNA showing that the intracellularly expressed single chain fragments are stably and efficiently expressed as cytosolic proteins. The expression of the anti-p21ras single chain antibodies in the cytoplasm of Xenopus laevis oocytes leads to the inhibition of the insulin-induced meiotic maturation. This finding represents the first successful application of the strategy of intracellular antibodies to block a complex biological process in the cytosol of vertebrate cells.

Transgenic plants expressing a functional single-chain Fv antibody are specifically protected from virus attack

Expression of viral genes in transgenic plants is a very effective tool for attenuating plant viral infection. Nevertheless, the lack of generality and risk issues related to the expression of viral genes in plants might limit the exploitation of this strategy. Expression in plants of antibodies against essential viral proteins could provide an alternative approach to engineer viral resistance. Recently, expression of complete or engineered antibodies has been successfully achieved in plants. The engineered single-chain Fv antibody scFv (refs 10, 11) is particularly suitable for expression in plants because of its small size and the lack of assembly requirements. Here we present evidence that constitutive expression in transgenic plants of a scFv antibody, directed against the plant icosahedral tombusvirus artichoke mottled crinkle virus, causes reduction of infection incidence and delay in symptom development.

Use of living columns to select specific phage antibodies

Here we demonstrate that it is possible to confront two recombinant microorganisms in order to select one using the other. We have shown that an epitope derived from p21ras expressed within the outer membrane protein, LamB, can be recognized both by the monoclonal antibody Y13-259, as well as the single chain Fv fragment derived from it. This specificity, which is maintained when the Y13-259 single chain Fv is expressed as a fusion protein with the phage fd gene 3 protein, has allowed us to use the living column of LamB-ras to purify Y13-259 phage from a background of non-binding phage, even at dilutions as high as 10 phage in 10(10) irrelevant phage.

[Extra-mammary Paget's disease. An HPV-correlated neoplasia?]

Eight cases of Paget's disease of the vulva and anogenital region are presented. Seven cases presented intraepithelial lesions and only one showed superficial intraepidermal diffusion. The average age of the patients in our series was 58.8 years. In all cases histochemical and immunohistochemical reactions were positive, except for the CEA reaction (only one case was positive). Specimens from our series were tested for presence of HPV 6, 11, 16, 18, 31, 33, 35 by in situ DNA hybridization. All cases were negative. Paget's disease, at the moment, is the only tumor of the low female genital tract non HPV-associated. Recurrences are very frequent even many years after radical surgery treatment.