Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LEECHES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed1999

Microsurgical replantation of a partial ear, with leech therapy.

Ear reconstruction is very difficult to perform and often results in a devastating deformity. The use of microsurgical replantation techniques has allowed very favorable aesthetic results. The authors report a case of partial ear replantation without venous repair with the use of medicinal leeches to decompress the acute venous congestion that occurred during postoperative care. Medicinal leech therapy can be very useful in partial ear replantation in cases with no venous repair.

Adult↗
PubMed2001

Development of a clinically useful mechanical leech device that promotes flap survival in an animal model of venous-congested skin flaps.

The authors describe the design and testing of a mechanical leech device that has shown greater efficacy in alleviating venous congestion and promoting skin flap survival than previously described clinical therapies. Abdominal skin flaps (3 x 6 cm) were raised on Sprague-Dawley rats and were subjected to two ischemic events that simulated clinical venous congestion. The animals received two treatments with the device prototype during 7-day experiment (N = 9). Flap perfusion was monitored with a scanning laser Doppler imager (LDI) and was normalized to adjacent skin perfusion. Photographic images of flaps at 7 days were assessed for areas of nonnecrotic tissue, and LDI data consisted of perfusion measurements at nine time points during the 7-day experiment. The device prototype was able to promote an average survival area in the flap of 60.0 +/- 3.5%, which was not only a significant (p < 0.05) increase over previously published control groups (8.0 +/- 5.0%) that did not receive any treatment, but was a significant increase over the same treatment schedule with clinically used leeches (34.6 +/- 7.3%). At 7 days, LDI data showed flap perfusion to be 65.6 +/- 7% of adjacent skin perfusion, a significant increase over this level at the end of the second ischemic event (21 +/- 1%; p < 0.05). These results suggest that this device could be used clinically to alleviate venous congestion and to promote flap survival. The device could also be useful for prophylactic treatments and to minimize treatment delays because its long shelf-life permits immediate availability when a treatment decision is made.

Animals↗
PubMed1997

Reduction of plasma clot stability by a novel factor XIIIa inhibitor from the Giant Amazon Leech, Haementeria ghilianii.

The blood-sucking leech, Haementeria ghilianii, has evolved a number of agents that attenuate haemostasis. Recently we have isolated a potent inhibitor of factor XIIIa, tridegin, in the salivary glands which is almost certainly involved in feeding. Addition of purified natural tridegin to plasma, prior to clotting with thrombin, results in clots that deform more readily as adjudged by the greatly reduced development of the storage modulus on application of a shear force. The increase in the storage modulus in developing plasma clots is a slow process and continues for many hours. The effect of tridegin is particularly great when the clots are permitted to age in this way, demonstrating the role of factor XIIIa in the process. The IC50 for this inhibition is 138 ng/ml. Clots formed in the presence of tridegin are also lysed more rapidly in vitro by the leech's own fibrinolytic enzyme, hementin (time for 50% lysis, 16.0 +/- 0.8 h versus 22.3 +/- 2.0 h, P < 0.05). The synergy with which these agents act together may provide lessons for therapy of thrombosis in man.

Animals↗
PubMed1992

Kainate/glutamate-induced changes in intracellular calcium and pH in leech glial cells.

Kainate evokes a non-desensitizing membrane depolarization in neuropile glial cells of the leech Hirudo medicinalis. We measured membrane potential and intracellular pH, pH(i), using double-barrelled pH-sensitive microelectrodes, and intracellular calcium, Ca2+i, using the change in fluorescence ratio of intracellularly injected fura-2, in these glial cells in situ. 20-50 microM kainate produced a depolarization of 18-28 mV and a decrease of pH(i) by 0.27 +/- 0.07 pH units. Ca2+i increased by 306 +/- 128 nM upon kainate, which could be inhibited by the non-NMDA antagonist CNQX. Glutamate (0.1 mM) also produced a fall in pH(i) and a rise in Ca2+i, which were however, much smaller. Quisqualate and N-methyl-D-aspartate had only small or no effects on membrane potential, pH(i) or Ca2+i. It is concluded that leech neuropile glial cells have a kainate-type glutamate receptor, which mediate significant transients of intracellular H+ and Ca2+.

Animals↗
PubMed1995

Replantation of the avulsed pinna: 100 percent survival with a single arterial anastomosis and substitution of leeches for a venous anastomosis.

We have presented an alternative form of management for the difficult ear replant in which conventional venous outflow cannot be reestablished. Early and aggressive medicinal leeching provided an excellent means of venous decompression until neovascularization had taken place. The primary use of leeches in such small composite replants may be superior to the time-consuming and technically difficult exercise of trying to find and anastomose suitable veins. In selected patients this technique may allow successful replantation of the amputated ear, thereby providing a superior aesthetic result to most forms of secondary reconstruction.

Adolescent↗
PubMed1990

Medicinal leeches: once again at the forefront of medicine.

Medical grade leeches have recently been used in the management of acute problems relative to venous congestion in patients with traumatic injuries and surgical problems. Specific cases, especially in the realm of reconstructive microsurgery, have demonstrated the effectiveness and application of leech therapy. Specific contraindications include arterial insufficiency from either anatomic or mechanical obstruction. We present five illustrative cases of successful therapeutic intervention.

Acute Disease↗
PubMed1994

Membrane properties of microglial cells isolated from the leech central nervous system.

Membrane potentials and channel properties of microglial cells isolated from the leech central nervous system and maintained in culture on different substrates were investigated by using the patch-clamp technique. As expected, microglia on concanavalin A (con-A) were round and stationary, whereas those on extract of extracellular matrix (ECM) were spindle shaped and mobile. The mean membrane capacitance was 9 +/- 1 pF (s.e., n = 46), and the input resistance ranged from 0.135 G omega to 21 G omega with a mean of 4.2 +/- 1.6 G omega (n = 19). On-cell patches exhibited no single-channel activity. Voltage-dependent Na+, K+ and Ca2+ currents typical of neurons were absent. Currents evoked in response to voltage ramps from -100 mV to +100 mV or to steps of 4 s duration reversed in sign at or near 0 mV and exhibited single-channel activity of increasing amplitude for incrementally larger positive and negative voltage steps. No differences between the membrane properties of microglial cells on con-A and on ECM were evident. Currents were increased in fluid in which Na+ was substituted with K+, and were decreased when Na+ was substituted with N-methyl-D-glucamine. Varying external [Cl-] was without effect, as was addition to the fluid of 100 microM anthracene-9-carboxylate, a Cl- channel blocker. Together these characteristics indicated a cation channel. Bath application of 100 microM serotonin reversibly increased both inward and outward currents as well as single-channel activity. It is concluded that cultured microglial cells isolated from the adult leech have high membrane resistance and cation channel activity influenced by serotonin.

Animals↗
PubMedDate not supplied

Serotonin depletion does not prevent intrinsic sensitization in the leech.

Intrinsic sensitization is a form of behavioral facilitation that is distinct from the extrinsic sensitization normally studied. To examine whether intrinsic and extrinsic sensitization are mediated by different physiological processes, the effects of 5,7-dihydroxytryptamine-induced serotonin (5-HT) depletion on intrinsic sensitization of the leech whole-body shortening response were observed. Previous experiments have shown that 5-HT depletion disrupts dishabituation and extrinsic sensitization of this behavior in the leech. Intrinsic sensitization was observed in preparations from both control and 5-HT-depleted animals, indicating that this form of behavioral facilitation was not affected by 5-HT depletion. The differences in the effects of 5-HT depletion on intrinsic versus extrinsic sensitization suggest that there are distinct neurophysiological processes mediating these two forms of behavioral facilitation. In addition, 5-HT depletion appeared to disrupt a putative extrinsic form of habituation of the shortening reflex. These data support the hypothesis that both intrinsic and extrinsic processes of neuromodulation mediate habituation and sensitization.

Analysis of Variance↗
PubMed1976

Modification and regeneration of synaptic connections in cultured leech ganglia.

Segmental ganglia of the central nervous system of the leech were maintained in culture medium outside the animal for several weeks in order to study the properties of synapses and regeneration by identified sensory and motor nerve cells. A variety of preparations were used, including single ganglia, chains of ganglia and ganglia connected to the areas of skin and muscle that they normally innervate in the animal. (1) For up to 10 weeks after removal from the animal, resting and action potentials recorded from sensory and motor neurons resembled those seen in normal ganglia. The same individual cell in a cultured ganglion could be recorded from with intracellular electrodes on a second occasion after an interval of a few days. (2) Sensory cells, identified as touch, pressure or nociceptive according to their morphology and electrical properties, continued to respond selectively to stimuli of the appropriate modality applied to their receptive fields in the skin; action potentials in motor cells caused contractions in the appropriate muscles. Culture of ganglia for more than 3 weeks caused the disappearance of synaptic potentials and a loss of transparency in ganglia. (3) Certain chemically mediated synaptic interactions between sensory and motor nerve cells became markedly changed in cultured ganglia. These changes appeared over the first 3 weeks and consisted of abnormally large excitatory and inhibitory synaptic potentials. The changes in synaptic transmission observed in culture were in many respects similar to those occurring in ganglia maintained within an animal after lesions have been made in the nervous system (Jansen et al. 1974). (4) The morphological appearances of sensory cells were compared in cultured and normal ganglia after injection of horseradish peroxidase. In cultured ganglia, the branching pattern appeared normal, but varicosities became more conspicuous. (5) When connectives linking cultured ganglia were crushed or cut, regeneration occurred. By 7 days, impulses propagated through the regenerated fibers and evoked synaptic potentials on cells within the next ganglion. The course taken by regenerating axons was observed in cells injected with horseradish peroxidase. The results again resembled those seen in animals with similar lesions. (6) The cultured ganglia provide preparations in which it is possible to analyze the mechanisms that underlie long-term changes similar to those seen in the leech central nervous system in situ.

Animals↗
PubMed2001

The structure of leech anti-platelet protein, an inhibitor of haemostasis.

Leech anti-platelet protein (LAPP) from the leech Haementeria officinalis is a collagen-binding protein that inhibits the collagen-mediated adhesion of blood platelets. The crystal structure of recombinant LAPP has been determined using single isomorphous replacement with anomalous scattering combined with solvent flattening and threefold molecular averaging. The model of LAPP has been refined to 2.2 A resolution (R factor 21.5%; free R factor 24.0%). LAPP contains an 89-residue C-terminal domain consisting of a central six-stranded antiparallel beta-sheet flanked on one side by an alpha-helix and on the other side by two extended loops with little secondary structure. A 36-residue N-terminal region is not visible in the electron-density map. This region is rich in glycine and lacks hydrophobic residues. It probably does not have a compact globular fold, but instead has an extended conformation and is flexible. The crystal packing suggests that LAPP may form tightly interacting dimers. The fold of the C-terminal domain of LAPP closely resembles that of the N-domain of hepatocyte growth factor (HGF), which classifies LAPP as a PAN domain. However, no significant sequence homology exists between LAPP and other PAN domains. Common structural features between LAPP and the HGF N-domain include two disulfide bonds that link the alpha-helix to the central region of the protein and five residues with a conserved hydrophobic nature that are located in the core of the domain. These conserved structural features may be an important determinant of the PAN-domain type of fold.

Amino Acid Sequence↗
PubMed2004

Social group size, potential sperm competition and reproductive investment in a hermaphroditic leech, Helobdella papillornata (Euhirudinea: Glossiphoniidae).

Social group size may affect the potential for sperm competition, and this in turn may favour ontogenetic adjustments in testicular mass according to the likely requirements for sperm and spermatophore production. In a number of comparative analyses of testis mass among vertebrate species that differ in mating system or social organization, increasing potential for sperm competition is associated with larger testis size. Intraspecific phenotypic plasticity should be able to produce the same pattern if social group size is heterogenous and reflects differing degrees of average sperm competition, but this intraspecific effect is less well studied. We tested the effect of social groups on both male and female investment in the simultaneously hermaphroditic leech, Helobdella papillornata. Leeches were placed in groups of one, two, four or eight. Sexual investment at the onset of reproductive maturity was quantified as the total testisac volume for male function and total egg volume for female function. We found that testisac volume (statistically adjusted for body size) showed a significant increase with increasing group size. Total egg volume (also adjusted for body size) was unaffected by group size. Our findings indicate adaptive developmental plasticity in male gonad investment in response to the potential for sperm competition.

Animals↗
PubMed1992

Ovohemerythrin, a major 14-kDa yolk protein distinct from vitellogenin in leech.

A 14-kDa protein was identified as a major component of mature oocytes of the leech Theromyzon tessulatum. This protein was, like vitellin, detected in the content of yolk granules and was purified by gel-permeation and ion-exchange chromatography. The yolk protein corresponded to an iron-binding protein which exists in a monomeric unglycosylated form and had no similarities to vitellin. However, a strong resemblance between this protein and sipunculid hemerythrin, a non-heme iron-binding protein, was observed on the basis of its characteristics including molecular mass, iron content, ultraviolet/visible spectrum, amino acid composition and N-terminal sequence. These similarities with hemerythrin and the accumulation of the protein in the oocyte justify the name ovohemerythrin given to the molecule. A coelomic-fluid protein immunologically related to ovohemerythrin was detected in vitellogenic animals. The protein was purified with the chromatographic procedure used to isolate ovohemerythrin from oocytes and was found to be similar to the oocyte protein. This circulating ovohemerythrin was present in large amounts in the coelomic fluid while gametogenesis is in progress, i.e. after the third and last blood meal of the animal (stage 3), except at the time of oocyte enlargement when its concentration decreases dramatically. However, in contrast to vitellogenin, which is detected specifically in the coelomic fluid of leeches at stage 3, circulating ovohemerythrin is also observed after the first (stage 1) and second (stage 2) blood meal. This observation suggests a more complex function for ovohemerythrin than being merely a yolk nutrient for the embryo.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of hirustasin, an antistasin-type serine-proteinase inhibitor from the medical leech Hirudo medicinalis.

Antistasin, a potent inhibitor of the blood coagulation factor Xa, is the prototype of a novel family of serine-proteinase inhibitors. We have now isolated, sequenced and characterized an antistasin-type inhibitor from the medical leech Hirudo medicinalis. Hirustasin (Hirudo antistasin) was purified to apparent homogeneity by cation-exchange and affinity chromatography. Amino acid sequencing of the 55 amino acid protein (M(r) 5866) revealed that hirustasin is the only antistasin-type protein known to consist of one domain only; 27% and 32% sequence identity was found to the first and second domains of antistasin, respectively, and a nearly exact conservation of the spacing of the ten cysteine residues. Hirustasin is the first inhibitor of tissue kallikrein identified in leeches, and is also a tight-binding inhibitor of trypsin, chymotrypsin and neutrophil cathepsin G. However, despite the high similarity to antistasin, particularly in the vicinity of the putative reactive-site peptide bond, hirustasin neither inhibits blood coagulation in vitro nor amidolytic activity of isolated factor Xa. Thus, structural elements other than the reactive site sequence significantly influence the specificity of antistasin-type proteinase inhibitors.

Amino Acid Sequence↗
PubMed1995

Isolation of a neuropeptide-degrading endopeptidase from the leech Theromyzon tessulatum.

Extracts of head parts prepared from the leech Theromyzon tessulatum hydrolyse the Gly3-Phe4 bond of synthetic [D-Ala2, Leu5]enkephalin and the Gly-His bond of benzoyl-Gly-His-Leu. The metabolism of benzoyl-Gly-His-Leu was completely inhibited by captopril, consistent with an angiotensin-converting enzyme activity. Such an enzyme has recently been isolated from T. tessulatum. However, the enkephalin hydrolysis by captopril (100 microM) was inhibited to a maximum of 70%. The residual activity hydrolyzing enkephalin was inhibited by phosphoramidon, consistent with the presence of endopeptidase-24.11, a mammalian enzyme implicated in the metabolism of neuropeptides. This enzyme was isolated using four steps of purification including gel-permeation and anion-exchange chromatographies followed by reverse-phase HPLC. This neuropeptide endopeptidase (of approximate molecular mass 45 kDa) hydrolyses, at pH 7 and 37 degrees C, both the Gly3-Phe4 bond of synthetic [D-Ala2, Leu5]enkephalin and the Phe8-His9 bond of angiotensin I. Cleavage of [D-Ala2, Leu5]enkephalin yields, respectively, the Tyr-D-Ala-Gly and Phe-Leu peptides with a specific activity of 29 nmol Tyr-D-Ala-Gly.min-1.mg protein-1 (Km 95 microM). The hydrolysis of angiotensin I yields angiotensin II and the dipeptide His-Leu with a specific activity of 1.2 nmol angiotensin min-1.mg protein-1 (Km 330 microM). The metabolism of these peptides was totally inhibited by phosphoramidon. This study therefore provides biochemical evidence for neuropeptide-degrading endopeptidases in leeches.

Amino Acid Sequence↗
PubMed1997

Amino-acid-sequence determination and biological activity of cytin, a naturally occurring specific chymotrypsin inhibitor from the leech Theromyzon tessulatum.

We purified a chymotrypsin inhibitor, designated cytin, from the rhynchobdellid leech Theromyzon tessulatum. This 7.4-kDa peptide was purified to apparent homogeneity by gel-permeation and anion-exchange chromatographies, followed by reverse-phase HPLC. The structure of cytin was determined by reduction, S-beta-pyridilethylation, automated Edman degradation, and electrospray mass spectrometry. Cytin is formed by the association of two protein chains, which are linked by a disulfide bridge. Chain A consists of 43 and chain B of 22 amino acid residues. Chain B exhibits 40-63% sequence similarity with the N-terminal sequences of subtilisin/chymotrypsin inhibitors isolated from barley seeds. Cytin inhibited chymotrypsin (Ki 600 pM) and weakly inhibited trypsin (Ki 350 nM). This chymotrypsin inhibitor, in contrast to others isolated from leeches, does not inhibit elastase or cathepsin G. Furthermore, cytin (10 microM) significantly diminishes the level of human granulocyte and monocyte activation induced by lipopolysaccharide (1 U/ml) in a manner similar to that of aprotinin. These data indicate that this chymotrypsin inhibitor may be biomedically significant.

Amino Acid Sequence↗
PubMed1993

Intracellular chloride activity and the effect of 5-hydroxytryptamine on the chloride conductance of leech Retzius neurons.

Intracellular Cl- activity (aCli) and 5-hydroxytryptamine (5-HT)-induced membrane currents of Retzius neurons in the central nervous system of the medicinal leech were measured using Cl- sensitive microelectrodes and a two-microelectrode voltage-clamp technique. At the membrane of Retzius neurons Cl- ions were not passively distributed. Under different conditions the chloride equilibrium potential (ECl, -60.1 mV for isotonic saline and -57.8 mV for a hypertonic saline) was negative with respect to the membrane potential (Em, -55 +/- 3.8 and -47 +/- 3.4 mV respectively). The endogenous neurohormone 5-HT always polarized the membrane of Retzius neurons in the direction of ECl. When voltage-clamping the membrane of Retzius neurons near the resting potential both in situ and in primary culture, application of 5-HT produced an outward current (I5-HT) and an increase in membrane conductance. Current-voltage relationships for I5-HT showed a slight outward rectification and reversal potentials of -61.6 +/- 3.1 mV in situ and -66 +/- 3.1 mV in primary culture, both values being comparable to the ECl of Retzius neurons as measured in situ. The results indicate that 5-HT increases the Cl- conductance of Retzius neurons, thereby hyperpolarizing the cell membrane and affecting both the excitability of the neuron and 5-HT release from it. This could affect the feeding and swimming behaviour of the leech.

Animals↗
PubMed2001

Leeching as initial treatment in a cat with polycythaemia vera.

Polycythaemia vera was diagnosed in a three-year-old domestic shorthaired cat referred because of seizures and a high packed cell volume (PCV). Laboratory examination revealed severe erythrocytosis (PCV 79 per cent). Diagnosis was reached by excluding causes for relative and secondary absolute polycythaemia. As phlebotomy proved impossible for initial treatment due to hyperviscosity, four leeches were used to suck blood and the PCV was consequently reduced to 64 per cent. A further 24 hours later, when bleeding at the sites of sucking had stopped, the PCV was 56 per cent. Long-term management of the condition was achieved with hydroxyurea (100 mg/cat once daily) and intermittent phlebotomy. Initial treatment using leeches in cases of polycythaemia vera is a simple, non-invasive, well tolerated and effective method where phlebotomy is not possible.

Animals↗