Pleiotrophin, the angiogenic and mitogenic growth factor: levels in serum and synovial fluid in rheumatoid arthritis and osteoarthritis : And correlation with clinical, laboratory and radiological indices.

BACKGROUND: Few studies have reported a possible involvement of pleiotrophin (PTN) in the pathophysiology of osteoarthritis (OA) and very little is known about its role in rheumatoid arthritis (RA). This study is to measure PTN in the sera and synovial fluids in RA and OA and to assess its relation to activity, functional class and radiological staging. SUBJECTS AND METHODS: Serum and synovial fluid samples were collected from 35 RA patients and 40 knee OA patients and serum samples were withdrawn from 20 healthy controls. Demographic, clinical and serological data were prospectively assessed. Functional and radiographic grades were also assessed. Serum and synovial fluid PTN levels were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no statistical significant differences (p > 0.05) on comparing the mean PTN level in sera of RA, OA patients and healthy controls. However the mean synovial fluid level of PTN in both patient groups was significantly higher than mean serum level (p < 0.001). Significant correlations between the serum PTN level and both morning stiffness duration (p = 0.008) and mHAQ score (p = 0.039) were only observed in RA patients. CONCLUSION: Our results point to a possible important role of PTN in RA and OA. We firstly report a serological pattern of PTN in the sera and synovial fluids of RA patients. However its implementation as a disease marker or a potential target therapy in both diseases awaits larger studies and further investigations.

Association of anthropometric qualities with vertical jump performance in elite male volleyball players.

AIM: The objective of this study was to examine the association between physical and anthropometric profiles and vertical jump performance in elite volleyball players. METHODS: Thirty-three elite male volleyball players (21±1 y, 76.9±5.2 kg, 186.5±5 cm) were studied. Several anthropometric measurements (body mass, stature, body mass index, lower limb length and sitting height) together with jumping height anaerobic power of counter movement jump with arm swing (CMJarm) were obtained from all subjects. Forward stepwise multiple linear regression analysis was performed to determine if any of the anthropometric parameters were predictive of CMJarm. RESULTS: Anaerobic power was significantly higher (P≤0.05) in the tallest players relative to their shorter counterparts. A significant relationship was observed between CMJarm and lower limb length (r2=0.69; P<0.001) and between the lower limb length and anaerobic power obtained with CMJarm (r2=0.57; P<0.01). While significantly correlated (P≤0.05) with CMJarm performance, stature, lower limb length/stature and sitting height/stature ratios were not significant (P>0.05) predictors of CMJarm performance. CONCLUSION: This study demonstrates that lower limb length is correlated with CMJarm in elite male volleyball players. The players with longer lower limbs have the better vertical jump performances and their anaerobic power is higher. These results could be of importance for trained athletes in sports relying on jumping performance, such as basketball, handball or volleyball. Thus, the measurement of anthropometric characteristics, such as stature and lower limb length may assist coaches in the early phases of talent identification in volleyball.

Aerobic training programs and glycemic control in diabetic children in relation to exercise frequency.

AIM: The aim of this study was to assess the effect of an aerobic training on glycemic control and lipid profile in diabetic children. METHODS: Thirty-three children with type 1 diabetes mellitus (T1DM) were equally divided in three groups. The control group (CG) did not perform any training intervention during the period of the investigation and the subjects were instructed to continue with their daily lifestyle patterns. The second group (G1) and the third group (G2) completed a six-month aerobic training programs. During the period of the investigation, G1 participated in one daily session (~60 min) of aerobic exercise twice weekly, while G2 performed in the form of daily session four times a week (~60 min). HbA1c and lipid profile were measured before training intervention, then after three and six months. RESULTS: The three-month periods was without significant changes of HbA1c in the two groups but significantly increased high-density lipoprotein cholesterol (HDL-C) in G1 (P<0.05). In G2, an increase of HDL-C was accompanied by a decrease of serum triglyceride (TG) (P<0.05). After six months, only HDL-C and TG levels were significantly lower in G1 (P<0.01), while in G2 HDL-C increased (68.8±5.7 mg/dL vs. 56.7 ±7.2 mg/dL; P<0.01), low-density lipoprotein cholesterol (LDL-C) (69.2±8.5 mg/dL vs. 81.6±11.8 mg/dL; P<0.01), TG concentrations decreased (60.7±6.9 mg/dL vs. 77.4±9.3 mg/dL; P<0.01) and HbA1c was significantly lower (6.8±1.1% vs. 8.2±1.5%; P<0.05), comparatively to those before training. CONCLUSION: However, the six-month periods showed that children exercising more than two times weekly significantly improved HbA1c and lipid profile. These results must encourage children with T1DM to regularly practice sporty activities for long periods.

Fabrication of tetraethylenepentamine functionalized alginate beads for adsorptive removal of Cr (VI) from aqueous solutions.

In this study, an innovative adsorbent based on tetraethylenepentamine (TEPA) functionalized alginate (Alg) beads (TEPA-Alg) was developed for the adsorptive removal of Cr (VI) from aqueous solutions. Chemical modification of alginate surface was carried out using p-benzoquinone (PBQ) as a coupling agent followed by functionalization with TEPA. The prepared functionalized beads were characterized using FTIR, TGA, SEM, and XPS tools. Results showed that the ion exchange capacity (IEC) significantly increased from 6.34 to 10.32 meq g-1 with increasing TEPA concentration up to 0.05 M. Furthermore, removal (%) of Cr (VI) increased gradually from 38 to 86% with rising TEPA concentration from 0.0125 M to 0.05 M. While only 22% was recorded using native alginate beads. The gained equilibrium data were fitted to Langmuir isotherm model with maximum adsorption capacity ~ 77 mg/g and the adsorption kinetics were well-expressed by pseudo-first-order model. Reusability studies showed good adsorption properties after 5 consecutive cycles. Results achieved by this study imply that the prepared functionalized TEPA-Alg beads could be efficiently utilized for the removing Cr (VI) ions from their aqueous solutions.

Fabrication of a novel low-cost superoleophilic nonanyl chitosan-poly (butyl acrylate) grafted copolymer for the adsorptive removal of crude oil spills.

A novel superoleophilic-hydrophobic nonanyl chitosan-poly (butyl acrylate) grafted copolymer was fabricated as a low-cost oil-adsorbent. Chitosan (CS) was coupled with a hydrophobic nonanal (N) to form nonanyl chitosan (NCS) schiff base, and followed by grafting with butyl acrylate monomers (ButA). The grafted copolymer was characterized by FTIR, TGA and SEM tools. The grafting percent was augmented and reached 88.5% with increasing ButA concentration up to 156 mM. Moreover, measurements of contact angle proved the superoleophilic character of NCS-g-poly (ButA) copolymer with an oil-contact angle 31°. Factors affecting the removal process such as contact time, oil type, oil dose, adsorbent dose, temperature and agitation speed were optimized. An increment in the oil removal (%) was observed with increasing the oil viscosity in the order of gasoil < mobil-1 oil < light crude oil < heavy crude oil. Besides, the adsorption process followed the pseudo-second order model and the equilibrium data were sufficiently fitted with the Langmuir model with a maximum adsorption capacity 108.79 g/g at 25 °C. Thermodynamic parameters computed from Van't Hoff plot confirmed the process to be exothermic, favorable and spontaneous. The results nominate the superoleophilic adsorbent as a potential oil- adsorbent for petroleum oil spills removal.

Heparin-binding EGF-like growth factor modulation by antiprogestin and CG in the baboon (Papio anubis).

The objectives of this study were to determine whether antiprogestin therapy or the infusion of human CG to mimic blastocyst transit in the baboon alters heparin-binding EGF-like growth factor expression during the window of implantation. During the menstrual cycle, heparin-binding EGF-like growth factor protein accumulation in the glandular epithelium was low in the proliferative phase and increased to maximal expression on d 5 and 10 postovulation. Stromal cells accumulated high levels of heparin-binding EGF-like growth factor in the proliferative phase, which decreased by d 5 postovulation. These transitional changes in both cell types were delayed when cycling baboons were treated with the antiprogestin ZK 137.316 during the luteal phase. The treatment with human CG had no effect on expression of heparin-binding EGF-like growth factor when compared with cycling baboons on d 10 postovulation and was comparable with that observed on d 18 and 22 of pregnancy. However, the superimposition of the antiprogestin with the human CG treatment also decreased expression in the epithelial cells. In summary, heparin-binding EGF-like growth factor accumulation in the epithelial glands is under the influence of progesterone and does not seem to be influenced by the paracrine secretion of trophoblast CG.

Multiple roles for heparin-binding epidermal growth factor-like growth factor are suggested by its cell-specific expression during the human endometrial cycle and early placentation.

Embryonic expression of the epidermal growth factor (EGF) receptor as well as embryonic and steroid-dependent uterine secretion of its ligand, heparin-binding EGF-like growth factor (HB-EGF), are temporally associated with the period of blastocyst implantation. We examined the temporal cell type-specific expression of HB-EGF in human endometrium during the menstrual cycle by immunohistochemistry and in situ hybridization. Early first trimester implantation sites were also examined to determine HB-EGF protein levels in decidual and fetal tissues. In the endometrial stroma, HB-EGF protein expression increased markedly during the late proliferative phase and then decreased in the early secretory phase. By contrast, luminal and glandular epithelial cells as well as blood vessel endothelium accumulated the protein between midcycle and cycle day 20, with peak expression observed during the period of uterine receptivity for implantation. HB-EGF expression decreased dramatically at the end of the cycle, before menses. Spatiotemporal expression of HB-EGF messenger ribonucleic acid demonstrated a similar pattern. During early pregnancy, HB-EGF immunostaining was noted in the decidua and in both villous and extravillous trophoblast populations. These findings suggest that HB-EGF promotes implantation and trophoblast invasion through paracrine and autocrine signaling as cells penetrate the stroma and displace the arteriole endothelium.

The epidemiology of schistosomiasis in Egypt: Assiut governorate.

In the Assiut, Egypt Epidemiology 1, 2, 3 investigation, a sample of 14,204 persons in 10 villages, 31 ezbas (satellite communities), and 2,286 households was drawn from a rural population of 1,598,607. Parasitologic examination of urine and stool were made for Schistosoma haematobium and S. mansoni, and physical and ultrasound examinations were made on a 20% subsample. The overall estimated prevalence of S. haematobium was 5.2 +/- 0.5 (+/- SE). This varied considerably by village and ezba, ranging from 1.5% to 20.9%, with ezbas having a slightly higher overall prevalence than villages. The overall estimated geometric mean egg count was 6.6 +/- 0.5 eggs per 10 ml of urine and was consistently low throughout the communities. Infection with S. haematobium was associated with age (peak prevalence of 10.6 +/- 1.5% in 15-19-year-old age group) males, children playing in the canals, a history of blood in the urine, and reagent strip positivity for hematuria and proteinuria. The prevalence of either hepatomegaly or splenomegaly detected by physical examination was low (4.0% and 1.5%, respectively). The prevalence of hepatomegaly determined by ultrasonography was substantially higher, 24.1%. The prevalence of periportal fibrosis (PPF) was 12.0%, but grade II or III PPF was present in less than 1%. Ultrasonography-determined hepatomegaly, in both the midclavicular line and the midsternal line, increased by age to more than 30%. Periportal fibrosis was more common in the age groups in which infection rates were the highest. At the village and ezba level of analysis, the prevalence of hepatomegaly, splenomegaly, and PPF tended to be higher in communities having the highest prevalence of infection with S. haematobium.

Action of babycurus-toxin 1 from the east African scorpion Babycurus centrurimorphus on the isolated cockroach giant axon.

A toxin named babycurus-toxin 1 (mol. wt 8191), from telson extracts of the scorpion Babycurus centrurimorphus, was found to depolarize the cockroach giant axon. It progressively blocked the evoked action potentials after a short period of limited repetitive activity and after 30 min of toxin action it became impossible to evoke responses to current stimulations. Voltage-clamp experiments on the sodium current indicated that the toxin in micromolar concentrations progressively decreased the transient inward peak sodium current, but also slowed the activation phase of this sodium current and maintained an inward current during the voltage pulses, which deactivated slowly. The toxin also induced in the insect axon a slowly activating-deactivating component of the sodium current. This suggests that the toxin modifies both activation and inactivation mechanisms of sodium channels. Thus there is some similarity in the electrophysiological effects between BcTx1 and the beta-toxins active on mammals.

Phlyctenular eye disease in association with Hymenolepis nana in Egypt.

It had been previously noticed that infection with parasites was common in children suffering from phlyctenulosis. In the present study the stools of 471 patients suffering from phlyctenular disease were examined and it was found that 62.6% of them had Hymenolepis nana ova in their stools as compared with 10.8% of the controls. All patients had Hymenolipis nana immune sera. Many of these patients had abdominal symptoms. Hymenolepis nana is a cestode parasite discovered by Bilharz in Cairo in 1851. Infections with it have the same age incidence and geographical distribution as phlyctenular eye disease. It has a tissue stage responsible for a state of hypersensitivity which is thought to be responsible for the phlyctenules.

[Computer-aided segmentation, form analysis and classification of 2975 breast microcalcifications using 7-fold microfocus magnification mammography]. / Computerassistierte Segmentierung und Formanalyse von 2975 mammären Mikroverkalkungen mit Hilfe der 7fachen Vergrösserungspräparateradiographie.

PURPOSE: To classify mammary microcalcifications for the prediction of malignancy by using computer-aided analysis of morphometric characteristics. MATERIALS AND METHODS: Seven-fold microfocus magnification radiography (direct magnification) was performed on 2975 paraffin embedded microcalcifications. After digitization of the radiographic films and segmentation of the microcalcifications, the morphometric characteristics, such as circumference, surface and polar transformation with determination of the greatest and smallest radius, were measured. Using the classification and regression tree (CART) statistical analysis program, the calcifications were classified by computer on the basis of the morphometric characteristics and the known histological result. RESULTS: Benign conditions were essentially represented by small round calcifications with a greatest radius of < or = 114.2 microm, a smallest radius of > 18.5 microm and a circumference of < or = 462.3 microm. Using > 70 % microcalcifications classified in a patient by the computer as "malignant," CART increases the frequency of malignant conditions, with the diagnostic separation between benign and malignant at an Az value (surface below the ROC curve) of 0.7863. CONCLUSION: A computer-assisted classification of individual microcalcifications on the basis of morphometric characteristics can supplement the information for a computer assisted mammographic diagnosis (CAD).

Exogenous oxytocin dilates the cervix in ewes.

Cervical anatomy in ewes usually prevents nonsurgical, intrauterine AI and transcervical embryo transfer (ET), which limits their commercial use in sheep. This study was conducted to determine whether oxytocin would dilate the cervix in ewes and permit passage of a stainless steel rod into the uterus. In Exp. 1, at 44 and 52 h after removal of progestogenated pessaries, ewes were injected i.v. with 0 (saline), 200, 400, or 600 USP units of oxytocin. Immediately before and after treatments, stainless steel rods were used to evaluate cervical dilation and determine whether the uterus could be entered. A rod could not be passed through the cervix and into the uterus in any of the saline-treated ewes. All doses of oxytocin given at 44 and 52 h after pessary removal dilated the cervix and permitted easy passage of a rod into the uterus. At both 44 and 52 h, a stainless steel rod was passed into the uterus in 33 of 43 (77%) of the oxytocin-treated ewes. In 93% (40/43) of these ewes, a rod could be passed into the uterus during either the 44-h or during the 52-h attempt. In Exp. 2, on d 9 after pessary removal, ewes were injected i.v. with oxytocin (400 USP units) at 6 or 12 h after i.v. estradiol-17 beta (0, 100, or 200 micrograms). Cervical dilation was evaluated as in Exp. 1. Dose of estradiol x time of oxytocin affected (P less than .01) the proportion of ewes in which a rod could be passed transcervically into the uterus.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental infections with Fasciola in snails, mice and rabbits.

Experimental infection trails of Lymnaea (cailliaudi) natalensis snails with miracidia of Fasciola hepatica revealed neither cercariae nor larval stages shed. Infection of white mice with metacercariae from field-collected snails proved to be negative for Fasciola eggs and immature juveniles or adults after 84 days post infection. The infection of eight rabbits (Oryctolagus cuniculus) has succeeded; two rabbits were infected, with a very low infection rate. Faeces of rabbits were negative for eggs. The worm burden was one and three worms from 40 fed metacercariae. The obtained fluke measures 23 mm in length by 4 mm in width. The tegument is covered with sharp-ending spines. The uterus contains few eggs. The intrauterine eggs measured 158 microm x 80 microm. According to the morphological characters of these flukes, they belong to F. gigantica.

Ideal intraspinal implantation site for the repair of ventral root avulsion after brachial plexus injury in humans. A preliminary anatomical study.

The advances made to date in root reimplantation for avulsion of the brachial plexus are modest considering that there are only reports from ten patients in the literature. However, the results are promising and should be applauded. The problem with reimplantation, in addition to the difficult surgical exposure, is to determine the ideal intraspinal implantation site for the graft. Given the non-permissive substrate properties of the CNS white matter, the outcome of grafts elsewhere in the spinal cord need to be evaluated. An inappropriate implantation site might explain the still modest recovery in this challenging group of patients. Consequently the microscopic anatomy of the cervical spinal cord segments C5 to T1 was studied. The aims were to 1--determine the relationships between the ventral gray horn and the ventrolateral sulcus of the spinal cord, and 2--analyse the location and course of the motoneuron fibres passing through the white matter to reach the ventral root. On the basis of the present findings it is proposed that reimplantation of nerve grafts or rootlets should be performed directly through the ventral root exit zone in contact with the ventromedial region of the ventral gray horn at a depth of 2 mm, rather than into the white matter of the lateral aspect of the cord. Initially we used a posterior approach with total facetectomies. An anterior approach is now evaluated for current use.

[Anti-insect scorpion toxins: historical account, activities and prospects]. / Les toxines anti-insectes de scorpions: historique, modes d'action et perspectives.

Some toxins from scorpion venoms, much more toxic to insects than to other animal classes, possess high affinity to Na+ channels. These anti-insect scorpion toxins have been divided into: 1) alpha toxins which lack strict selectivity for insects, do not compete with following groups of anti-insect toxins, resemble other alpha scorpion toxins by their structure and their ability, as alpha anemone toxins, to prolong insect axonal action potential durations through a drastic slowing down of the Na+ current inactivation, 2) excitatory insect selective scorpion toxins which induce in blowfly larvae an immediate fast paralysis; in isolated cockroach axons, they depolarize and induce a sustained repetitive activity of short (normal) action potentials through a shift of Na+ activation mechanism towards more negative potentials and some decrease of inactivation at these potential values, 3) depressant insect selective neurotoxins which cause a slow progressive flaccid paralysis of larvae, depolarize insect axons and reduce or even suppress evoked action potentials; resting depolarizations which are antagonized by a post-application of TTX, are due to the opening of sodium channels at very negative potential values and to the suppression of their inactivation mechanism. The decrease of the maximal Na+ conductance following flaccid toxin action may be understood if toxin-modified channels opened at very negative potentials values remain open (or re-open) for much longer times than in control conditions and pass by substate less conductant states. Anti-insect scorpion toxins become of major interest into insect neurophysiology and also into insect pest control, due to their specific target sites and to the recent constructions of insecticidal baculovirus expressions of several of these toxins.

Alpha-scorpion toxins binding on rat brain and insect sodium channels reveal divergent allosteric modulations by brevetoxin and veratridine.

At least six topologically separated neurotoxin receptor sites have been identified on sodium channels that reveal strong allosteric interactions among them. We have studied the allosteric modulation induced by veratridine, binding to receptor site 2, and brevetoxin PbTx-1, occupying receptor site 5, on the binding of alpha-scorpion toxins at receptor site 3, on three different neuronal sodium channels: rat brain, locust, and cockroach synaptosomes. We used 125I-AaH II, the most active alpha-scorpion toxin on vertebrates, and 125I-Lqh alpha IT, shown to have high activity on insects, as specific probes for receptor site 3 in rat brain and insect sodium channels. Our results reveal that brevetoxin PbTx-1 generates three types of effects at receptor site 3:1) negative allosteric modulation in rat brain sodium channels, 2) positive modulation in locust sodium channels, and 3) no effect on cockroach sodium channel. However, PbTx-1 activates sodium channels in cockroach axon similarly to its activity in other preparation. Veratridine positively modulates both rat brain and locust sodium channels but had no effect on alpha-toxin binding in cockroach. The dramatic differences in allosteric modulations in each sodium channel subtype suggest structural differences in receptor sites for PbTx-1 and/or at the coupling regions with alpha-scorpion toxin receptor sites in the different sodium channels, which can be detected by combined application of specific channel modifiers and may elucidate the dynamic gating activity and the mechanism of allosteric interactions among various neurotoxin receptors.

In vitro folding and functional analysis of an anti-insect selective scorpion depressant neurotoxin produced in Escherichia coli.

The selective toxicity of depressant scorpion neurotoxins to insects is useful in studying insect sodium channel gating and has an applied potential. In order to establish a genetic system enabling a structure-activity approach, the functional expression of such polypeptides is required. By engineering the cDNA encoding the depressant scorpion neurotoxin, LahIT2, behind the T7 promoter, large amounts of recombinant insoluble and nonactive toxin were obtained in Escherichia coli. Following denaturation and reduction, the recombinant protein, constructed with an additional N-terminal methionine residue, was subjected to renaturation. Optimal conditions for reconstitution of a functional toxin, having a dominant fold over many other possible isoforms, were established. The recombinant active toxin was purified by RP-HPLC and characterized. Toxicity (ED50) to insects, binding affinity (IC50) to an insect receptor site, and electrophysiological effect on an insect axonal preparation were found to be similar to those of the native toxin. Substitution of the C-terminal glycine by a Gly-Lys-Lys triplet did not abolish folding but affected toxicity (3.5-fold decrease) of LqhIT2. Apparently, this efficient bacterial expression system (500 micrograms HPLC-purified toxin/1 liter E. coli culture) provides the means for studying structure/ activity relationship and the molecular basis for the phylogenetic selectivity of scorpion depressant neurotoxins.

Application of neural networks to the real-time diagnosis of acute toxoplasmic infection in immunocompetent patients.

Neural networks constitute a relatively new, radically different approach to the interpretation and recognition of subtle diagnostic patterns in multivariate data. In this study the use of neural networks with a single serum sample for rapid real-time recognition of recent toxoplasmic infection was investigated. A neural-network model was implemented on the basis of data obtained by four serological methods--dye test, indirect fluorescence assay, indirect hemagglutination assay, and IgM immunosorbent agglutination assay--and was "trained" to extract features of acute infection by application to an analysis of 65 immunocompetent patients, 10 of whom were in fact acutely infected. The trained model correctly classified all 10 cases of acute infection. On its application to 61 additional infected patients, this method correctly identified seven cases as potentially acute. Our study shows that neural networks can discern diagnostic patterns from variables that individually have limited utility in the diagnosis of acute toxoplasmosis.

Maurotoxin and the Kv1.1 channel: voltage-dependent binding upon enantiomerization of the scorpion toxin disulfide bridge Cys31-Cys34.

Maurotoxin (MTX) is a 34-amino acid polypeptide cross-linked by four disulfide bridges that has been isolated from the venom of the scorpion Scorpio maurus palmatus and characterized. Maurotoxin competed with radiolabeled apamin and kaliotoxin for binding to rat brain synaptosomes and blocked K+ currents from Kv1 channel subtypes expressed in Xenopus oocytes. Structural characterization of the synthetic toxin identified half-cystine pairings at Cys3-Cys24, Cys9-Cys29, Cys13-Cys19 and Cys31-Cys34 This disulfide bridge pattern is unique among known scorpion toxins, particularly the existence of a C-terminal '14-membered disulfide ring' (i.e. cyclic domain 31-34), We therefore studied structure-activity relationships by investigating the structure and pharmacological properties of synthetic MTX peptides either modified at the C-terminus ¿i.e. MTX(1-29), [Abu31,34]-MTX and [Cys31,34, Tyr32]D-MTX) or mimicking the cyclic C-terminal domain [i.e. MTX(31-34)]. Unexpectedly, the absence of a disulfide bridge Cys31-Cys34 in [Abu 31,34]-MTX and MTX(1-29) resulted in MTX-unrelated half-cystine pairings of the three remaining disulfide bridges for the two analogs, which is likely to be responsible for their inactivity against Kv1 channel subtypes. Cyclic MTX(31-34) was also biologically inactive. [Cys31,34, Tyr32]D-MTX, which had a 'native', MTX-related, disulfide bridge organization, but a D-residue-induced reorientation of the C-terminal disulfide bridge, was potent at blocking the Kv1.1 channel. This peptide-induced Kv1.1 blockage was voltage-dependent (a property not observed for MTX), maximal in the low depolarization range and associated with on-rate changes in ligand binding. Thus, the cyclic C-terminal domain of MTX seems to be crucial for recognition of Kv1.3, and to a lesser extent, Kv1.2 channels and it may contribute to the stabilization and strength of the interaction between the toxin and the Kv1.1 channel.

A recombinant insect-specific alpha-toxin of Buthus occitanus tunetanus scorpion confers protection against homologous mammal toxins.

We have constructed a cDNA library from venom glands of the scorpion Buthus occitanus tunetanus and cloned a DNA sequence that encodes an alpha-toxin. This clone was efficiently expressed in Escherichia coli as a fusion protein with two Ig-binding (Z) domains of protein A from Staphylococcus aureus. After CNBr treatment of the fusion protein and HPLC purification, we obtained approximately 1 mg recombinant apha-toxin/l bacterial culture. The toxin, called Bot XIV, displays no toxicity towards mammals but is active towards insects as shown by its paralytic activity against Blatella germanica cockroach and by electrophysiological studies on Periplaneta americana cockroaches. The Bot XIV protein fused to two Z domains is highly immunogenic in mice and induces production of antisera that specifically recognize and neutralize highly toxic components that had been injected into mice. This fusion protein could be very useful for development of potent protective antisera against scorpion venoms.