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At least 667 records · Page 37Linked to original sources
PubMed1975

[The blocking action of snake venom polypeptides on the cholinergic mechanisms of leech dorsal muscle].

The blocking action of alpha-polypeptides from the venoms of elapid snakes (Bungarus multicinctus and Naja naja siamensis) was studied on leech dorsal muscle. It was shown that these neurotoxins failed to inhibit the responses to mononitrogen cholinomimetics (acetylcholine, nicotine, carbamylcholine, etc.). The capacity of neurotoxins to inhibit the responses to the bisquaternary cholinommimetics depended upon the length of the molecule. The neurotoxins were active against the "shorter" cholinomimetics, such as decamethonium, and bischolinic esters of malonic, succinic and glutaric acids. The "longer" cholinomimetics (bischolinic esters of adipinic, pimelic, suberic, azelaic, sebacic acids retained their full activity after the treatment of leech dorsal muscle by neurotoxins. Possible explanations of the selective action of neurotoxins are discussed.

Acetylcholine↗
PubMed2002

[Relationship between population dynamic of freshwater leech Whitmania laevis and chemical factors of water].

The population size of freshwater leech Whitmania laevis had been observed every month in Guangzhou kaleyard slot from 1994 to 1998, and ten chemical factors of water were measured. The relationship between the population dynamic of W. laevis and chemical factors was studied by stepwise regression analysis method. The results showed that the population size dynamic of W. laevis was different every year. The maximum of population size appeared in April, May, and June, and the total population size of three months was accounted for 57.14-71.18% of whole year. The major chemical factors that effected on the annual population size were different every year, and the factors included pH value, PO(4)3-, Na+, Ca2+, and Mg2+. Fe3+ was the chief chemical factor effecting on population size during the 5 years observation. The behavior of leech W. laevis was also described in this paper.

Animals↗
PubMed2001

[Study of protective effect of leech, radix Salviae miltiorrhizae and its composite recipe on vascular endothelial cells in rats with blood stasis syndrome].

OBJECTIVE: To study the protective effect for Chinese medicine of promoting blood circulation and removing blood stasis (PBCRBS) on vascular endothelial cells (VEC) in rats, aiming at further research on the mechanism of blood stasis syndrome and PBCRBS. METHOD: Establishing a model of blood stasis with endothelial damage by means of giving rats an injection of adrenalin and making it swim in ice-cold water, then measuring the number of circulating endothelial cells (CEC) in whole blood and rheology. Moreover observing the change of the above indexes after the rats have taken Leech, Radix salviae miltrorrhizae (RSM) and its composite recipe for 5 days or 10 days. RESULT: It could increase the number of CEC accompanied by whole blood viscosity, fibrinogen and hematocrit in rats with blood stasis. But for groups taking Chinese medicine, the number of CEC was decreased distinctively and blood rheology was improved. CONCLUSION: The rat with blood stasis syndrome suffered from obvious injury of VEC. The Leech, RSM and its composite recipe could protect VEC.

Animals↗
PubMed2003

Imaging reveals synaptic targets of a swim-terminating neuron in the leech CNS.

In the leech, the command-like neuron called cell Tr2 is known to stop swimming, but the connections from cell Tr2 to the swim central pattern generator have not been identified. We used fluorescence resonance energy transfer voltage-sensitive dyes to identify three neurons that are synaptic targets of cell Tr2. We then used electrophysiological techniques to show that these connections are monosynaptic, chemical, and excitatory. Two of the novel targets, cell 256 and cell 54, terminate swimming when stimulated. These neurons are likely to mediate swim cessation caused by cell Tr2 activity, and thus play the role of intermediate control cells in the leech CNS.

Animals↗
PubMed1992

An inhibitor of collagen-stimulated platelet activation from the salivary glands of the Haementeria officinalis leech. II. Cloning of the cDNA and expression.

Salivary glands of the leech Haementeria officinalis contain a protein, leech antiplatelet protein (LAPP), that specifically blocks collagen-mediated platelet aggregation (Connolly, T. M., Jacobs, J. W., and Condra, C. (1992) J. Biol. Chem. 267, 6893-6898). Degenerate oligonucleotides whose sequences were derived from two short peptides from V8 digests of the native LAPP were used as primers to generate a polymerase chain reaction (PCR) product which contains the cDNA region coding for the sequence between these two peptides. Using this PCR product as a hybridization probe, phage containing cDNA clones were isolated containing the entire deduced amino acid sequence for LAPP. Computer analysis of the amino acid sequence predicts a peptidase cleavage site between a 21-residue pre-peptide and a mature protein of 126 amino acids. A DNA insert to express the predicted mature LAPP protein was generated by PCR amplification using phage-derived cDNA clones as a substrate. This insert encoded a fusion protein with the leader sequence of the yeast alpha mating factor and the mature LAPP cDNA. These PCR products were cloned into the yeast expression vector pKH4 alpha 2. A KEX 2 Lys-Arg endopeptidase cleavage site was placed NH2-terminal to the predicted mature protein. This vector transfected into the yeast Saccharomyces cerevisiae directs expression of a secreted mature protein at levels up to 200 mg of LAPP/liter of culture medium. The recombinant protein was comparable to native LAPP in its electrophoretic mobility, its reactivity with anti-LAPP antisera, and its biological activity including inhibition of collagen-stimulated platelet aggregation and the adhesion of platelets to collagen. Availability of significant quantities of recombinant LAPP opens the way to further biochemical structure/function studies and to studies on the effects of an inhibitor of collagen-stimulated platelet aggregation in vivo.

Amino Acid Sequence↗
PubMed2005

Leech therapy: a history.

Bloodletting is an ancient procedure that was utilized for curing the ills of man. This article traces the use of leeches for bloodletting therapy from ancient Greek times to the Chapin Harris era in the 1840s to modern day usage by plastic surgeons. The leech is described as both a parasite and a therapeutic agent. The techniques used by both medicine and dentistry are historically documented.

Europe↗
PubMedDate not supplied

Nasal leech--a rare cause of severe anemia.

Spontaneous epistaxis, nasal trauma and foreign bodies are common causes of nasal bleed in children. Epistaxis and haematemesis due to leeches have been reported in literature. Here we present a rare case of severe anemia caused by a single leech infestation of nasal cavity that required blood transfusion.

Anemia↗
PubMed1991

A mannose-specific recognition mediates the defasciculation of axons in the leech CNS.

We are studying a mannose-specific recognition mediating the projection of axons in the synaptic neuropil of the embryonic leech CNS. A functional class of neurons, the sensory afferents, can be distinguished by a mannose-containing epitope that is asparagine-linked to a 130 kDa surface protein and is reactive with the monoclonal antibody Lan3-2. Sensory afferents project as a tightly fasciculated bundle through peripheral nerves but, upon arriving in the CNS, defasciculate into the synaptic neuropil. This defasciculation allows the previously bundled sensory afferents to form an arborization in the synaptic neuropil. Three lines of experimental evidence indicate that the defasciculation is mediated by the sensory afferent's mannose-containing Lan3-2 epitope. The defasciculation is inhibited (1) by blocking the Lan3-2 epitope with Lan3-2 Fab fragments, (2) by cleaving the asparagine-linked carbohydrate moieties from surface proteins with the glycosidase N-glycanase, and (3) by competing for a putative mannose-binding protein with the neoglycoprotein mannose-BSA [albumin, p-aminophenyl alpha-D-mannopyranoside (26 mol monosaccharide/mol albumin)]. In addition to inhibiting the defasciculation, the three perturbation reagents also elicited the refasciculation of axons that had defasciculated prior to their application. These three different experimental approaches provide strong evidence that carbohydrate recognition regulates the projections of sensory afferents in the leech synaptic neuropil. Carbohydrate interactions therefore can play a major role in regulating the neuronal architecture in the CNS.

Amidohydrolases↗
PubMed1991

Origin of segmental identity in the development of the leech nervous system.

The leech embryo develops its segmental body plan by means of a stereotyped cell lineage. Each hemilateral segment arises from a small set of embryonic blast cells via a comparable sequence of formative cell divisions, and for the most part, lineally homologous cells manifest similar patterns of differentiation in the various hemisegments. Nonetheless, some identified central neurons undergo segment-specific or laterally asymmetric patterns of neuropeptide expression and/or cell death. Certain aspects of this regional diversification result from competitive cell interactions which occur at the level of the postmitotic neuron. However, the neuron's segmental identity is lineally determined, being inherited from its blast cell progenitor over several intervening rounds of mitosis. To learn more about the molecular basis of this phenomenon, we have isolated and begun to characterize leech homeobox genes which are related to the genes that govern segmental identity in other organisms.

Amino Acid Sequence↗
PubMed2000

[Leeches (Hirudinea: Piscicolidae and Glossiphonidae) infecting lake fish in the Ukiel, Warniak and Wulpińskie. Preliminary study].

The aim of the study was to determine leeches found on the lake fishes. From the lake Ukiel, 213 roaches (R. rutilus) and from the lake Wulpińskie 202 were examined between Nov. 1988 and Dec. 1999. From the Warniak 258 roaches and 9 tenches (Tinca tinca) were examined between May 1998 and Nov. 1999. Warniak on roach (R. rutilus) 4 Piscicola geometra and Hemiclepis marginata on the fish body were found, tench (Tinca tinca) P. geometra were found on gills. Ukiel on roach Piscicola pojmanskae on gills were found. Wulpińskie on roach P. pojmanskae and Piscicola sp. as well as 2 Caspiobdella fadejewi on gills were found. Prevalence and intensity of fish infection with leeches was low in all lakes. C. fadejewi and P. pojmanskae are the first recorded on the lake fishes. Further investigations are necessary since they can result in informations concerning inhabitation of new microhabitants with P. geometra gills.

Animals↗
PubMed1991

Development of serotonin-induced ion currents in identified embryonic Retzius cells from the medicinal leech (Hirudo medicinalis).

Retzius cells and the cutaneous baroreceptive P-cells of adult medicinal leeches (Hirudo medicinalis) respond to 5-HT by Cl- as well as by monovalent cation conductances (Drapeau et al., 1989). However, chemical synaptic connections between Retzius cells (Liu and Nicholls, 1989) as well as Retzius cells and P-cells in culture (Drapeau and Sanchez-Armass, 1988) are mediated by postsynaptic Cl- currents in response to 5-HT release from the presynaptic cell. It was the aim of the present study to find out whether the response, which has been shown to be involved in synaptic transmission or whether the cation current, which has so far only been observed upon extrasynaptic 5-HT application, dominates during embryogenesis. Currents induced by transmitter application with a fast perfusion system were measured with a single-electrode voltage clamp and patch pipettes in whole-cell configuration. Control experiments, performed on Retzius cells from adult leeches after 1 d in culture, showed Cl- currents in response to 5-HT application in all cells investigated. Ninety percent of the cells tested showed additional 5-HT-elicited Na+, K+, or both currents. However, the conductance of cation currents amounted only to 10% of the Cl- currents. Embryonic Retzius cells were identified in dissociated cultures by their violet-blue fluorescence acquired by preincubation of intact ganglia or embryos in culture medium containing the autofluorescent 5-HT analog 5,7-dihydroxytryptamine. The first responses to 5-HT were measured at embryonic day 10 (E10), after voltage-activated Ca2+ and Na+ currents had already developed. 5-HT application induced exclusively Cl- currents until E16. This suggests that the receptor-channel complex, which also mediates synaptic responses, is expressed first in measurable quantities. Hence, there is currently no indication that extrasynaptic receptors dominate in immature cells in this preparation.

Animals↗
PubMed1991

The segmentation of the leech nervous system is prefigured by myogenic cells at the embryonic midline expressing a muscle-specific matrix protein.

In the leech, adult muscle cells and embryonic mesodermal/myogenic cells express the cell-type-specific Laz 10-1 epitope on extracellular matrix-associated proteins. Using this muscle-specific epitope as a marker, we found the following correlations between the development of identifiable myogenic cells at the embryonic midline and the segmentation of the leech CNS into 32 reiterative ganglia. (1) During the production of mesodermal and ectodermal stem cells, cell bodies of midline myogenic cells create 32 anterior-posterior intervals along the midline of the embryonic germinal plate. The mesoblasts then rearrange themselves into 32 somites whose spacing follows the intervals between the midline myogenic cell bodies. (2) Bilateral segmental zones of myogenic differentiation originate in juxtaposition to the midline myogenic cells. (3) The first two types of muscle precursors develop from midline and adjacent bilateral myogenic cells; they are the precursors of the CNS muscles and of three groups of ventral blood sinus muscles. These two types of muscle precursors demarcate the boundaries of the territory within which neuroblasts proliferate and coalesce into segmental hemiganglionic primordia: Cell bodies of muscle precursors, like cornerstones, demarcate the anterior and posterior borders of the hemiganglionic primordia; their longitudinal processes surround the expanding hemiganglionic primordia on the medial, lateral, dorsal, and ventral aspect. The contours of muscle precursors and midline myogenic cells are sharply delineated by immunohistochemical staining of the Laz 10-1 epitopes. In contrast, undifferentiated mesoblasts are surrounded by diffuse layers of stained epitopes, which are expressed at fluctuating levels. Because elevated levels of this matrix epitope are associated with mesodermal/myogenic cells undergoing morphogenetic rearrangements, it may participate in the molecular mechanisms underlying the segmentation of the nervous system.

Animals↗
PubMed1991

Normally unused positional cues guide ectopic afferents in the leech CNS.

Central projections from peripheral sensory neurons segregate into distinct, ventrally positioned longitudinal tracts within the segmental ganglia of the leech Hirudo medicinalis. As documented here, there is an additional tract in the neuropils of the fifth and sixth body ganglia, located at the lateral margin and formed by afferent axons (the "sex afferents") originating from sensory neurons located in the male and female genitalia. Ablation of the genitalia results in the complete absence of this additional tract. We asked (1) whether segmental differences exist in the distribution of pathway cues available to the sex afferents, and (2) whether central pathway selection by these axons is specific. We transplanted the primordia of the male genitalia to several ectopic positions posterior to the sixth body segment and labeled the ectopic sex afferents in order to examine their paths in the CNS. In about 50% of the experimental animals, afferent axons originating in the transplanted tissue segregated into a distinct lateral fiber bundle within the neuropil of a nearby ganglion, in a position corresponding to their normal one in the sex ganglia. The sex afferents therefore find their normal pathways even in the ganglia of inappropriate segments, although these pathways are not used by any other afferents in these ganglia. We propose, therefore, that the positional cues employed by afferent axons to select appropriate pathways in the ganglionic neuropil are expressed in all segments of the leech CNS, regardless of whether such cues are normally used by afferent axons in each segment.

Afferent Pathways↗
PubMed1991

Internalization of gap junctions between neuron and glial cell and formation of annular lamellar bodies in Chinese leech Whitmania pigra.

This paper reveals the formation of annular lamellar body (ALB) in the ganglion of leech by means of in situ fixation and the lanthanum nitrate tracer technique. This formation involves both wrapping and internalization of the gap junctions between glial processes themselves, as well as between neuron and glial process. The results indicate that there is probably an active process of internalization of membrane structures involving gap junctions between neuron and glial cell in the central nervous system in leech. The functions of ALB are discussed.

Animals↗
PubMed1991

Leech--an unusual cause of (laryngo-tracheal) obstruction.

A case of acute laryngo-tracheal obstruction in a 12-year old boy is presented. A live leech was removed from the larynx under general anaesthesia. A high index of suspicion of leeches as foreign bodies in children with acute onset of respiratory distress associated with hemoptysis and early surgical intervention is emphasized.

Airway Obstruction↗
PubMed1990

Interactions between adjacent ganglia bring about the bilaterally alternating differentiation of RAS and CAS neurons in the leech nerve cord.

Antibodies to small cardioactive peptide (SCP) label a segmentally iterated subset of cells in the leech nerve cord, including the previously identified alternating SCP (AS) neurons. Unlike the majority of leech neurons, these cells are asymmetrically distributed in the adult nerve cord. Moreover, each AS neuron shows a strong tendency to lie on alternate right and left sides in successive ganglia. Previous work has shown that these unpaired neurons arise from bilaterally paired embryonic homologues, only 1 of which takes on the mature immunoreactive phenotype. The 2 AS homologues within a ganglion compete for this fate, in that either the right or the left homologue will become a mature AS neuron with a high degree of reliability if its contralateral homologue is ablated during embryogenesis. In this paper, we demonstrate the existence of interactions between neurons in adjacent ganglia that could account for the alternation of sides observed during normal development. The unilateral ablation of a single AS homologue neuron forced its contralateral homologue to take on the mature AS fate, and this consistently biased the side of AS development in adjacent, unlesioned ganglia both anterior and posterior to the lesion. One of the AS neurons, the caudal alternating SCP (CAS) cell, was injected with Lucifer yellow in adult nerve cords and was shown to have a large primary axon that extends into more anterior ganglia, as well as other, finer axons that are variable in number and arrangement. If the interganglionic interaction of AS neuron homologues is mediated by their primary axons, signals of developmental import must be transmitted both anterogradely and retrogradely along the axon's length. The present results indicate that the development of individual AS neurons is influenced by homologous cells located in the same and neighboring ganglia and suggest that the final, multisegmental patterning of the AS neuron distribution is not predetermined, but rather, arises as an emergent property of the cell interactions that occur during nervous system differentiation.

Animals↗
PubMed1985

FMRF-amide-like substances in the leech. I. Immunocytochemical localization.

FMRF-amide-like immunoreactivity (FLI) was localized to approximately 50 neurons in each segmental ganglion of the medicinal leech using immunocytochemical techniques. Although most of these neurons were iterated in each segmental ganglion, some were more restricted in their segmental distribution. The head and tail ganglia likewise contained numerous FMRF-amide-like immunoreactive cells. In addition to cell bodies, many nerve processes and varicosities were also immunoreactive throughout the ganglion. All labeling of FLI was blocked by preabsorption of the anti-FMRF-amide antiserum with synthetic FMRF-amide. Using a combination of Lucifer Yellow cellular injection and indirect immunofluorescence techniques, we identified several of the neurons possessing FLI. Identified neurons included excitatory motor neurons (HE, RPE, LPE, AE, and L), the HA modulatory neuron, interneuron cell 204, and cells of unknown function (AP). The processes of HE motor neurons and HA modulatory neurons which innervate the heart tubes were also immunoreactive. These results indicate a role for FMRF-amide-like substances as neurochemical signals in the leech.

Animals↗
PubMed1989

[Effects of death of a single neuron on the functional organization of the neuronal ensemble in the leech].

The reaction of leech nervous system after elimination of individual mechanosensory neuron by intracellular Pronase injection were studied. In the motor neurons connected with killed cells at 14-90th days after the operation there were the changes of the resting membrane potential and amplitude of postsynaptic potentials developed by the stimulation of mechanosensory neuron. It is suggested that the leech nervous system serves as the dynamic formation depending on changes of neuronal ensemble structure.

Animals↗