Single-channel properties of cloned cGMP-activated channels from retinal rods

Single-channel properties of a cloned channel activated by cyclic GMP have been analysed. The mRNA encoding for the channel was injected into oocytes of Xenopus laevis and the current flowing through a single ionic channel activated by cGMP was studied in excised patches under voltage-clamp conditions. The ionic channel activated by cGMP had a single-channel conductance of 32 +/- 2 pS at +120 mV and 25 +/- 4 pS at -120 mV, and its conductance was not significantly affected by increasing the cGMP concentration from 20 microM to 200 microM. The single-channel currents in the presence of NH+4, Na+, K+, Li+ and Rb+ in the medium bathing the cytoplasmic side of the membrane at +140 mV were 5.3, 4.7, 3.8, 1.3 and 0.8 pA, respectively. The single-channel current in the presence of Cs+ was less than 0.5 pA. Ca2+ and Mg2+ (both 0.5 mM) in the presence of 100 microM cGMP did not appreciably affect the channel activity at membrane potentials more negative than -80 mV, whereas at +100 mV they reduced the single-channel conductance by about threefold. The ionic selectivity and the blockage by divalent cations of the native channel found in amphibian rods and in the cloned channel from bovine rods are quite similar. However, the cloned channel has well-resolved openings, especially at positive membrane voltages, whereas the native channel is characterized by a continuous flickering between the open and closed state.

Cloning and expression of an anti-nerve growth factor (NGF) antibody for studies using the neuroantibody approach

1. The neuroantibody approach, based on the expression of selected monoclonal antibodies by cells of the nervous system, has recently been described (Cattaneo and Neuberger, 1987; Piccioli et al., 1991). In order to apply this experimental strategy to study the role of nerve growth factor (NGF) in the central nervous system (CNS), we exploited the monoclonal antibody (mAb), alpha D11, which neutralizes very efficiently the biological activity of NGF, both in vitro and in vivo (Cattaneo et al., 1988). 2. The alpha D11 antibody chains were cloned and expressed in COS cells as rat/human chimaeric proteins. The cloned antibody was shown to display all the properties of the parental alpha D11 antibody, including its ability to neutralize NGF biological activity. 3. This will allow us to engineer the expression of recombinant alpha D11 antibodies in the CNS, to study the role of NGF in the developing and adult nervous system. This approach can be extended to other neurotrophic factors for which neutralizing monoclonal antibodies are available.

Hematologic values of fetal blood obtained by means of cordocentesis

Fetal blood values were evaluated from 541 cordocenteses. Simple regressions were used to find a correlation between blood values and gestational age. We found a linear increase in hemoglobin concentration and hematocrit throughout gestation; a linear decrease of the mean corpuscular volume with the gestation was evidenced as a regular decrease in mean corpuscular hemoglobin. Lastly, the mean corpuscular hemoglobin concentration was constant during the gestation; a linear increase of the platelet count and the nucleated cells was also evidenced. We suggest that each fetal medicine unit should have its own reference ranges. It will permit to accurately diagnose fetal infection, fetal anemia, or any fetal disease where alterations of hematopoiesis have been described.

Expression of TRK-T1 oncogene induces differentiation of PC12 cells

The TRK-T1 oncogene, isolated from a human thyroid carcinoma, represents a rearranged form of the high affinity nerve growth factor (NGF) receptor encoded by the NTRK1 gene; it is created by an intrachromosomal rearrangement fusing the NTRK1 tyrosine kinase domain to the 5' portion of the TPR gene. We have investigated the effect of the TRK-T1 oncogene in PC12 cells, a model system for studying neuronal differentiation and the mechanism of action of NGF. Here, we report that, in PC12 cells, the TRK-T1 oncogene has a differentiating effect that resembles that of NGF and requires the phosphorylation of the oncoprotein. Our results are consistent with the hypothesis that TRK-T1, as well as the original TRK oncogene, induces PC12 differentiation by mimicking the action of NGF bound to its receptor.

MRI and cognitive patterns in relapsing-remitting multiple sclerosis

We studied the relationships between magnetic resonance imaging (MRI) and the Luria-Nebraska Neuropsychological Battery (LNNB) in 64 patients with relapsing-remitting multiple sclerosis (MS). MRI films were scored according to arbitrary descriptive criteria designed to emphasize patterns of alterations. Five groups were created: group 1 and 2 had typical discrete white matter lesions, group 3 had confluent lesions, group 4 had large discrete lesions and group 5 had only few small lesions. In addition, groups 2 and 3 had evidence of parenchymal atrophy. Groups 2 and 3 were the most impaired on the LNNB, but none of these patients was actually demented. Groups 1 and 5 were globally intact in spite of very different mean age and MRI pattern. Group 4 was composed of younger subjects with a shorter disease duration; they showed mild loss of attentive and abstracting abilities. We suggest that since their MRI was showing greater signs of local biological activity their mental deficits may be a transitory condition capable of two distinct outcomes: a favorable one as in groups 1 and 5, and a slowly progressive one associated with loss of brain tissue as in groups 2 and 3.

Clinical and histologic effects of topical treatments of vulval lichen sclerosus. A critical evaluation

A randomized study was conducted on 79 patients with vulval lichen sclerosus who were treated for three months with four topical drugs including testosterone (2%), progesterone (2%), clobetasol propionate (.05%) and a cream based preparation. To evaluate the efficacy of the treatments, patients were examined before and after therapy for symptoms, gross appearance of the lesions and histopathologic features. Patients treated with clobetasol had a better response than responses recorded in the other groups. Remission of symptoms occurred in 75% of patients treated with clobetasol compared to 20% treated with testosterone, 10% treated with progesterone and 10% treated with a cream based preparation. The clobetasol group was the only group with gross changes and histologic evaluations before and after treatment, that showed a highly significant difference (P < .001). In a condition characterized by epidermal atrophy, we observed a significant reduction in epidermal atrophy after treatment. This study suggests that clobetasol propionate (.05%) (a very potent topical steroid) is the therapy of choice in vulval lichen sclerosus.

[Solitary perforated diverticulum of the right colon. Five cases]

Solitary perforated diverticulum of the right colon is a very uncommon acute disease in emergency surgery, and usually a preoperative diagnosis of acute appendicitis is performed. Five cases of solitary perforated diverticulum of the right colon are presented. Preoperative diagnostic difficulties as well as surgical procedures are discussed.

[Clobetasol vs. testosterone in the treatment of lichen sclerosus of the vulvar region]

The paper describes a study carried out in 40 patients affected by lichen sclerosus (LS) of the vulva. The mean age of patients was 60.9 years (range 27-83) and 31 were in menopause. Patients were divided randomly into two groups of 20. The symptoms (itching, burning, pain, dyspareunia), clinical aspects (atrophy, hyperkeratosis, sclerosis) and histological alterations (atrophy of the epithelium, edema, inflammatory infiltrate, fibrosis) were quantified in each patient by a score. The mean scores relating to the three parameters examined were then calculated for each group. One group was treated with testosterone propionate 2% and the other with a strong synthetic corticosteroid, clobetasol dipropionate 0.05%. After 24 weeks of treatment patients were again evaluated in relation to clinical (symptoms and clinical aspects) and histological parameters, following the procedure used before the start of treatment. The mean scores obtained were then compared with those before the start of treatment. Statistical analyses were performed using Student's t-test. Testosterone was found to be effective in relation to symptoms but no significant change was observed in relation to clinical aspects and histological alterations. It also caused major secondary effects which led to the suspension of treatment in one patient. Clobetasol was shown to be highly effective both in relation to symptoms and in terms of clinical aspects and histological alterations, and did not cause any noteworthy collateral effects, especially contact dermatitis. In the context of the objective parameters examined in this study, sclerosis and hyperkeratosis were easily modified by corticosteroid treatment in comparison to atrophy, especially in those patients with a longer duration of disease.(ABSTRACT TRUNCATED AT 250 WORDS)

A recombinant cell line expressing a form of the Y13-259 anti-p21ras antibody which binds protein A and may be produced as ascites

We have recently reported the molecular cloning of the immunoglobulin genes encoding the variable regions of the rat anti-p21ras antibody, Y13-259. These genes were reassembled into expression vectors supplying DNA sequences encoding human gamma 1 and kappa constant domains, as well as the leader sequence for antibody secretion, thus yielding Hu-Y13-259, a secretory anti-p21ras antibody containing human constant regions. We now report the creation of a recombinant cell line, NS0/Hu-Y13-259/B6, secreting high levels of the Hu-Y13-259 Ig. The antigen specificity of this recombinant antibody was demonstrated to be identical to that of the parental Y13-259, i.e. the amino acid sequence 60-76 of the p21ras protein. Unlike the parental cell line, the recombinant cells could be grown as ascites in mice, allowing the production of large quantities of the protein A-binding Hu-Y13-259 antibody.

Plasma alpha-melanocyte-stimulating hormone, beta-endorphin, met-enkephalin, and natural killer cell activity in vitiligo

BACKGROUND

The immune system is important in the pathogenesis of vitiligo, and emotional stress has precipitated vitiligo in some patients. Opioid peptides, beta-endorphin, met-enkephalin, and alpha-melanocyte-stimulating hormone (MSH) act as immunomodulators, and their secretion increases during periods of stress.

OBJECTIVE

To see whether these three neuropeptides might be related to vitiligo itself or to some alterations of the immune system in patients with vitiligo, we compared circadian variations in their plasma concentrations and natural killer cell activity of peripheral blood lymphocytes in 14 patients with vitiligo with those of 12 healthy subjects.

METHODS

Plasma concentrations of neurohormones were evaluated by radioimmunoassay (immunoradiometric assay for beta-endorphin). Natural killer cell activity (NKCA) was assayed against K562 cells by 51Cr release technique. Data were compared by the Student t test and analyzed by cosinor analysis.

RESULTS

The NKCA in vitiligo patients was higher than in controls but had similar circadian rhythm. alpha-MSH had no circadian rhythm in controls or in patients; plasma alpha-MSH levels were the same. Daily met-enkephalin and beta-endorphin oscillations in patients were no longer circadian. beta-Endorphin plasma levels in stable vitiligo were higher than in controls. There were no differences between patients with active vitiligo and normal subjects. Met-enkephalin plasma levels were generally higher in vitiligo patients, especially in the one with active vitiligo, than in controls.

CONCLUSION

In vitiligo there are aberrations in neuropeptide, beta-endorphin, and met-enkephalin secretion. The plasma met-enkephalin level is positively correlated with the aggressiveness of the disease.

'Phytoantibodies': a general vector for the expression of immunoglobulin domains in transgenic plants

Sequences encoding the immunoglobulin heavy-chain variable (VH) domains were engineered in a new general purpose vector to transform plants via Agrobacterium. The expression of an isolated VH domain (IVD) after introduction into the plant genome has been monitored by northern, western and immunohistochemical analysis. Immunoblotting showed that the polypeptide was stably expressed and accounted for up to 1% of the soluble protein fraction. It is therefore proposed that single immunoglobulin domains of suitable specificity expressed in plants may constitute an effective system to inhibit the activity of molecules involved in plant pathology or plant development.

Neuroantibodies: molecular cloning of a monoclonal antibody against substance P for expression in the central nervous system

We present a strategy to study functional and/or developmental processes occurring in the nervous system, as well as in other systems, of mice. This strategy is based on the local expression of specific monoclonal antibodies (mAbs) by cells of the nervous system. As an application of this strategy, we report the cloning of the anti-substance P rat mAb NC1/34HL. Functional substance P-binding antibodies were reconstituted from the cloned variable domains by using vectors for expression in myeloma cells. With these and other vectors a general system for the cloning and expression of mAbs under a series of promoters (of the rat VGF8a gene, the neurofilament light-chain gene, and the methallothionein gene) has been created. The activity of these plasmids was confirmed by expressing the recombinant NC1/34HL mAb in GH3 pituitary cells, PC12 pheochromocytoma cells, and COS cells. DNA from the described constructs can be used to target the expression of the NC1/34HL mAb to the central nervous system of transgenic mice. This procedure will allow us to perturb substance P activity in a controlled way in order to dissect its multiple roles.

Immunohistologic evaluation of the effect of cyclosporine treatment on the lichen planus immune infiltrate

We have investigated immunohistologically the cutaneous immune infiltrate in the lesions of five patients with severe, extensive lichen planus of recent onset before and after 15 days of oral, low-dose cyclosporine therapy (3 mg/kg/day). Before therapy, we observed an abnormal bandlike cellular infiltrate localized in the papillary dermis, composed mostly of CD3+ cells, with a prevalence of CD4+ cells. Infiltrating lymphocytes showed markers of activation (HLA-DR antigens and interleukin 2 receptor), and there were many Langerhans (CD1+) cells in the dermal infiltrate. After 15 days of cyclosporine therapy, we observed a dramatic decrease in the total number of T cells and a corresponding decrease in interleukin 2 receptor-positive activated CD25+ cells and in antigen-presenting cells (CD1+ and CD14b+). These changes were concurrent with clinical improvement. Our results are compatible with the hypothesis that the inhibition of CD4 T cells by cyclosporine might explain the drug's therapeutic action and that the interaction between antigen-presenting cells and CD4 T cells is important in the pathogenesis of lichen planus.

Lichen sclerosus and squamous hyperplasia of the vulva. A clinical study of medical treatment

One hundred thirty-eight cases of nonneoplastic epithelial disorders of the vulva treated with medical therapy from 1984 to 1988 were evaluated at the University of Florence, Florence, Italy. The 67 cases of lichen sclerosus were treated with testosterone propionate or progesterone ointment for 32 weeks. The 31 cases of squamous hyperplasia were treated with corticosteroid ointment for 16 weeks. The 40 patients with lichen sclerosus associated with squamous hyperplasia were treated with corticosteroid ointment for 12 weeks and then with testosterone propionate ointment for another 20. To evaluate the efficacy of the treatments, the patients were examined before and after therapy. The evaluation took into account the symptoms and gross appearance of the lesions, which were given a score of 1-3. Considering all the cases evaluated, a total regression of symptoms occurred in 82 patients (59.4%), while a partial regression occurred in 37 (26.8%). Furthermore, there was a total regression of gross changes in 68 cases (49.3%) and a partial one in 43 (31.1%). The best results were obtained with squamous hyperplasia, which lichen sclerosus, alone or associated with squamous hyperplasia, yielded less successful results.

Immunohistochemical evidence of skin immune system involvement in vulvar lichen sclerosus et atrophicus

Biopsies taken from vulvar lesions in 12 women affected by vulvar lichen sclerosus et atrophicus (LSA) have been processed for immunohistological study. Activated (HLA-Dr+) T cells, associated with CD1a+ accessory cells, were found in the dermis in all cases, with architectural patterns varying in relation to the histological phase (early, well developed, old) of the lesion. Interestingly, the number of epidermal CD1a+ Langerhans cells (LCs) was increased in all cases, without any correlation with the amount of the dermal infiltrate and with the histological phase of the lesions. In fact, also in old lesions the number of epidermal CD1a+ LCs was increased, and the sparse dermal lymphoid cells showed a persistent HLA-Dr antigen expression. These data, indicating the persistent activation of epidermal antigen-presenting cells and lymphoid cells in all the evolutive phases of vulvar LSA, suggest a possible involvement of the skin immune system in the pathogenesis of LSA.

Intracellular immunization. Cloning and intracellular expression of a monoclonal antibody to the p21ras protein

Following the demonstration that intracellular expression of antibodies ('intracellular immunization') may be utilized to engineer new traits in mammalian cells, we undertook experiments to perturb the function of p21ras proteins, by engineering the intracellular expression of the anti-p21ras antibody Y13-259. The variable regions of this antibody have been cloned and, after verifying their antigen binding activity, expressed in general purpose vectors for the intracellular expression of antibodies. The results confirmed that the cloned antibody has been efficiently expressed both in the secretory and the intracellular forms. Thus, intracellular immunization of mammalian cells against p21ras, or any other antigen for which a monoclonal antibody is available, can now be performed.

Immunohistological evaluation of basal cell carcinoma immunoinfiltrate during intralesional treatment with alpha 2-interferon

We investigated the peritumoral and intratumoral immune infiltrate in 6 basal cell carcinomas (BCCs) treated with recombinant alpha 2b-interferon. Each BCC was injected intralesionally three times a week for 3 weeks with 1.5 x 10(6) IU of interferon per injection (total dose 13.5 x 10(6) IU). The immunohistological study was done before the start of interferon therapy and 15 days afterwards, using a series of monoclonal antibodies and an immunocytochemical technique. Before therapy the infiltrate consisted mainly of CD3+ (T) cells, with prevalence of CD4+ (helper/inducer) T cells. The percentage of T cells expressing interleukin-2 receptor (CD25+ cells) was higher in the tumor nests than in the peritumoral infiltrate (20% and 11% respectively). CD1+ (Langerhans) cells and CD14b+ cells (monocytes/macrophages) were present in the peritumoral infiltrate in all cases (9% +/- 5% and 14% +/- 7% respectively). Very few CD56+ (natural killer), CD15+ (granulocytes) and CD20+ (B) cells were observed in the peritumoral infiltrate and none at all in tumor nests. After 15 days of interferon therapy, we observed an increase in peritumoral and intratumoral CD4+ cells. There was a decrease in the number of CD25+ cells and of CD1+ cells in the peritumoral infiltrate. The number of intratumoral CD25+ increased. No variations were seen in CD14b, CD15, CD20, and CD56 positive cells. Eight weeks after completion of therapy, two BCCs were cleared and the remaining four showed clinical and histological improvement. These results may indicate a direct effect of interferon against BCC; in addition the immunohistological findings suggest that intralesional interferon enhances T cell mediated immune response, especially in tumor nests.(ABSTRACT TRUNCATED AT 250 WORDS)

T cell subpopulations in vitiligo: a chronobiologic study

The circadian rhythms of helper (CD4) and suppressor (CD8) T cells from the peripheral blood of 12 vitiligo patients (seven with active disease, five with static) and 12 healthy control subjects were studied. Patients with active vitiligo had a lower percentage of CD4+ cells than did control subjects at 0000 hours and at 0600 and 1200 hours; there were no differences between these values in patients with static vitiligo and those in control subjects. The percentage of CD8+ cells were lower at 1200 and 1800 hours in both active and static vitiligo patients than in control subjects. Cosinor analysis of the CD4+ cells showed a circadian rhythm in static vitiligo, whereas the rhythmicity was lost in active vitiligo. CD8+ cells did not show any circadian rhythm in either active or static vitiligo. Our data show more striking aberrations for T cell subtypes in active vitiligo than in static vitiligo. They suggest that cell-mediated immunity may play a role in the pathogenesis of the disease.

Expression and targeting of intracellular antibodies in mammalian cells

Genes encoding the heavy and light chains of a hapten-specific IgM antibody were modified by site-directed mutagenesis to destroy the hydrophobic leader sequences and allow expression in the cytoplasm of non-lymphoid cells. The in situ assembly of the mutant heavy and light chains was tested in transfected cell lines by immunofluorescence using anti-idiotypic antibodies. A positive diffuse cytoplasmic staining was observed. This demonstrated that the antibody polypeptide chains could assemble in the cell cytoplasm and led us to ask whether antibodies could be further targeted to the nucleus. Mutations were therefore made in which the leader sequence of the light chain was replaced by the nuclear localization signal of the SV40 large T antigen. Transfectants in which the heavy chain lacking the hydrophobic leader was expressed together with a light chain carrying the nuclear localization signal were selected and a nuclear distribution of the assembled antibody was found. Thus, it should prove possible to target a specific antibody to the cell nucleus with the aim of interfering with the function of a nuclear antigen.

Effectiveness of cyclosporine treatment in severe psoriasis: a clinical and immunologic study

The effectiveness of low doses of cyclosporine (3 to 5 mg/kg/day) for short-term treatment in 13 patients with severe psoriasis was studied. The psoriasis cleared in 12 of 13 patients within 3 to 4 weeks of treatment, and there was appreciable improvement in the thirteenth patient. No major side effects were observed: two patients showed biochemical evidence of slight transient renal dysfunction and three others had cutaneous infections (two viral and one mycotic). An immunohistologic study showed that the psoriatic plaques contained an infiltrate composed mainly of activated helper T lymphocytes. After 15 days of cyclosporine treatment, CD4+ cells were significantly fewer in the epidermis and dermis, and Langerhans cells were more regularly distributed in the epidermis. Our studies of neutrophil chemotaxis showed that it is not significantly influenced by cyclosporine in vitro but is decreased in vivo.

Enzymes of human cervical mucus: a comparative study on fertile and infertile mucus and on the endocervical epithelium

We report a comparative study on protein and enzyme content of human periovulatory cervical mucus and endocervical epithelium. The salient results of our investigation are summarized in the following three points: 1) The method of taking of cervical mucus samples may markedly affect the results of protein and enzyme assays. It is warmly advisable to collect mucus samples from the endocervical canal. 2) Cervical mucus from women diagnosed as having cervical-factor infertility is oligoproteic and lacks some enzyme activities always present in normal cases. 3) Human cervical mucus and endocervical epithelium are very similar as for the enzyme distribution, but show quite different LDH-isoenzyme patterns. In the latter tissue, the H subunits constitute about 77 per cent of the whole LDH, suggesting that this enzyme here is functioning to produce pyruvate rather than lactate.

The mode of action of nerve growth factor in PC12 cells

This review deals with the mechanism of nerve growth factor action. In view of the many and diversified effects of this growth factor, and since it could utilize different mechanism(s) in distinct types of cells, we have confined our analysis to the best characterized and more extensively studied target, the clonal cell line PC12. When exposed to NGF in vitro, these neoplastic cells recapitulate the last major steps of neuronal differentiation, i.e., the commitment to become a neuron and the acquisition of the neuronal phenotype. This is characterized by electrically excitable neurites, a display of a highly organized cytoskeleton, and the specific chemical and molecular neuronal properties. These effects are elicited upon the interaction of NGF with a receptor whose gene has been cloned and whose kinetic properties are now relatively well characterized. It is not yet clear, on the contrary, if and which of the several potential second messengers (cAMP, Ca, or phosphoinositides) that undergo marked fluctuations following NGF binding, transduce and amplify the NGF message. Among both the early and late effects of NGF is the modulation of expression of several genes. Some of the products of these genes are mainly restricted to nerve cells and others appear to play a crucial role in regulating the proper assembly of cytoskeletal elements. It is hypothesized that this complex array of chemical, molecular, and ultrastructural changes is triggered by NGF, not through activation of a single pathway, but more likely via combinatorial processes whereby several intracellular signals interplay before the irreversible commitment of becoming a neuron is undertaken.

Three distinct types of monoclonal antibodies after long-term immunization of rats with mouse nerve growth factor

This article reports the results of a systematic investigation of the different types of antibodies produced in the course of a long-term immunization of rats with mouse nerve growth factor (NGF). We have characterized three types of monoclonal antibodies, namely: (1) antibodies that bind to NGF and inhibit its binding to target cells and its biological activity in culture (type A); (2) antibodies that bind to and precipitate NGF but do not inhibit its binding to target cells or its biological activity (type B); (3) antibodies that fail to recognize NGF itself, but inhibit nonetheless its binding to target cells (type C). These antibodies bind to an antigen present on NGF target cells and not on rat fibroblasts lacking NGF receptor. They appear thus to be antiidiotypic antibodies directed against the NGF receptor, developed as a consequence of the long-term immunization with NGF.

Polymeric immunoglobulin M is secreted by transfectants of non-lymphoid cells in the absence of immunoglobulin J chain

Plasmids were constructed in which expression of genes encoding the heavy and light chains of a hapten-specific IgM antibody is under control of a heat shock promoter. Glioma, phaeochromocytoma and other non-lymphoid cell lines transfected with the plasmids were able to process and secrete immunoglobulin following heat induction. The glioma transfectants were studied in detail and were shown to secrete polymeric IgM in a yield similar to that obtained with a plasmacytoma. However, the glioma IgM was not associated with J chain and was largely composed of pentamers and hexamers. Thus, neither J chain nor other lymphoid-specific proteins are required for assembly and secretion of polymeric IgM although the absence of J chain may encourage hexamer formation.

[Acute poisoning caused by methemoglobinemia-inducing substances. 6 cases]

Six patients were admitted to intensive care in Lodi Hospital with acute poisoning by substances causing methemoglobinaemia. They were treated with antidotes, purifying substances, blood exchange and symptomatic intensive care. The patients were observed 1-3 hours after ingestion of the poison. Three patients (50%) died. This is in line with reports in the literature given the severity of the poisoning. Three patients recovered completely and without sequelae. The importance of early diagnosis with particular attention to anamnestic data and the peculiar clinical symptoms of this syndrome is emphasised as essential for the prompt treatment required. A new classification for the causes of methemoglobinaemia based on pathogenetic criteria is proposed.

A functional domain on the alpha-latrotoxin molecule, distinct from the binding site, involved in catecholamine secretion from PC12 cells: identification with monoclonal antibodies

Seven monoclonal antibodies (mAbs) have been produced against alpha-latrotoxin (alpha-Latx), the toxin component of black widow spider venom that stimulates release of neurotransmitters from PC12 cells. These mAbs were characterized by an enzyme-linked immunosorbent assay and by neutralization analysis of the secretagogue properties of the toxin. The production of a panel of mAbs, possibly directed against different epitopes of alpha-Latx, provides a useful set of reagents to dissect the molecular regions of the toxin having different functions and to describe steps of its mode of action in responsive cells. Attention was focused on one of these mAbs (4C4.1), which inhibits in a dose-dependent fashion both toxin-stimulated and crude venom stimulated dopamine release from PC12 cells, prevents toxin-induced 45Ca2+ accumulation in PC12, alters toxin-dependent phosphoinositide breakdown, and prevents toxin-induced channel formation in artificial lipid bilayers. Since, within certain experimental conditions, mAb 4C4.1 is able to recognize the toxin bound to cells, we conclude that its effects were not a consequence of a direct interference with binding. On the basis of kinetic analysis of mAb interference on toxin action, expressed as accumulation of inositol phosphates and transmitter secretion, we suggest that the described effects result primarily from the blockade of an event immediately successive to binding and central for the full expression of toxin action. The availability of mAb 4C4.1 now makes possible the molecular characterization of the toxin moiety responsible for such an event.

Changes in enzyme levels in human cervical mucus during the menstrual cycle

Cervical mucus is a complex secretion produced by the endocervical epithelium. A comparative analysis of 30 enzymes was carried out on 15 women during their periovulatory period (days 10 to 16 of the menstrual cycle). Nine different enzymes were always found to be present in the cervical mucus. Changes in enzymatic activity were further studied in two of the women, one with a normal (27-day) and the other with a short (20-day) menstrual cycle. The data were compared with those for the same enzymes in the saliva of these two women. Each woman's ovulation time was determined through hormone measurements in urine and blood, as well as by recording basal body temperature and by Billing's method. Our results indicate that a maximum peak occurs for several enzymes during the periovulatory period.

Synthesis and content of a DNA-binding protein with lactic dehydrogenase activity are reduced by nerve growth factor in the neoplastic cell line PC12

We have previously demonstrated that synthesis of a 34 kD protein having specific, high affinity for single-stranded DNA (34kD-ssb protein), is markedly inhibited by nerve growth factor (NGF) in the neoplastic clonal cell line PC12. We report here that total content as well as mRNA for this protein are progressively reduced in PC12 cells undergoing mitotic arrest and morphological differentiation induced by NGF. It is also shown that binding of the 34K-ssb protein to ssDNA is fully inhibited by NADH but not by NAD+ or by several other nucleotides. Enzymatic tests on the possible NADH/NAD+-dependent dehydrogenase activity of the 34K-ssb protein have demonstrated that it has lactic dehydrogenase activity (LDH) with a specific activity comparable to that of rabbit muscle. Furthermore, the 34K-ssb protein has the same peptide mapping as LDH purified from rat muscle. Antibodies directed against the 34K-ssb protein cross-react with the rabbit muscle enzyme and, vice versa, antibodies raised against rabbit LDH cross-react with the 34K-ssb protein. It is concluded that the 34K-ssb protein is identifiable with the type M of LDH, although possible differences in primary structure of the two proteins may have escaped the present studies. We hypothesize that interaction of the PC12 lactic dehydrogenase with ssDNA occurs also in vivo, as indicated by the findings reported in the accompanying paper, and may be modulated by the cellular content of NADH which, in turn, is related to energy metabolism.

Nuclear localization of a lactic dehydrogenase with single-stranded DNA-binding properties

In the preceding article [1] we identified the 34 kD single-stranded DNA-binding (ssb) protein, whose synthesis is inhibited in PC12 cells concomitantly with nerve growth factor (NGF)-induced mitotic arrest, with the enzyme lactic dehydrogenase (LDH-ssb protein). Localization studies performed with antibodies raised against the LDH-ssb protein demonstrate the presence of a pool of this protein in the nucleus of several cell types. The nuclear association of this protein is sensitive to DNase treatment of the cells and quantitative electron microscopy confirms that the LDH-ssb protein is located close to chromatin structures. These results point to a possible involvement of the LDH-ssb protein in some nuclear function(s).

Some molecular features of human cervical mucus

1) The time preservation effect of the enzymatic activities present in human cervical mucus has been studied. 2) In order to protect the enzymatic activities of the mucus from bacterial impurities, the enzymes studied were assayed in presence of NaN3. 3) The effect of an acid pH likes present in the vagina was also studied: a low pH exerts a marked inhibition on mucus enzymes. 4) the use of nonionic detergents for mucus solubilization does not produce a marked increase of the enzymatic activities studied. 5) A NADP-dependent malate dehydrogenase in peri- and post-ovulatory period has been identified. 6) The presence in mucus of at least four lactate dehydrogenase isoenzymes has been demonstrated and their absolute values determined.

Nerve growth factor inhibits the synthesis of a single-stranded DNA binding protein in pheochromocytoma cells (clone PC12)

Arrest of mitosis and neurite outgrowth induced by nerve growth factor (NGF) in rat pheochromocytoma cells (clone PC12) is accompanied by a progressive inhibition of the synthesis of a protein that binds to single-stranded but not to double-stranded DNA. Time course experiments show that this inhibition is already apparent after a 2-day incubation with NGF and is maximum (85-95%) upon achievement of complete PC12 cell differentiation. Inhibition of the synthesis of this single-stranded DNA binding protein after 48 hr of incubation with NGF is potentiated by concomitant treatment of PC12 cells with antimitotic drugs acting at different levels of DNA replication. Purification on a preparative scale of this protein and analysis of its major physicochemical properties show that: (i) it constitutes 0.5% of total soluble proteins of naive PC12 cells; (ii) its molecular weight measured by NaDodSO4/PAGE is Mr 34,000 (sucrose gradient centrifugation under nondenaturing conditions yields a sedimentation coefficient s20,w of 8.1 S, indicating that the native protein is an oligomer); (iii) amino acid analysis demonstrates a preponderance of acidic over basic residues, while electrofocusing experiments show that it has an isoelectric point around 8.0; (iv) approximately 15% of the protein is phosphorylated in vivo. It is postulated that control of the synthesis of this protein is connected with activation of a differentiative program triggered by NGF in the PC12 neoplastic cell line at some step(s) of DNA activity.

Acute urinary retention: a rare onset sign of ovarian cystic teratoma

A rare case of sudden urinary retention due to a mature cystic teratoma of the left ovary in a previously asymptomatic adolescent girl is reported.

[Transabdominal echotomography in the staging of tumors of the bladder]

Transabdominal wall ultrasonography in the study of the bladder tumours is a simple and athraumatic method. In this prospective study the ultrasonographic patterns considered allow the differentiation among three principal classes: I group: superficial tumours with intact bladder wall; II group: invading tumours with the disappearance of the bladder wall behind the tumour (it is not possible to differentiate a superficial muscle involvement to a deeper invasion); III group: tumours with extra-vesical extension. The ultrasonic stage grouping has been compared with pathological staging, in a series of 46 patients (1981-1982). The I group (superficial tumours), corresponding to Pis-P1 pathological stage, and the III group, corresponding to P4, have a good accuracy (85% and 87,5%). In the II group, corresponding to P2-P3, the accuracy is less (72%) and it is not possible to differentiate between the two pathological stages. Transabdominal wall ultrasonography should be the first investigation in the preoperatory staging of bladder tumours.