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At least 127 records · Page 7Linked to original sources
PubMed1997

Ocular leech infestation in a child.

PURPOSE: To describe a patient with manifestations of ocular leech infestation. METHOD: Case report. RESULTS: The ocular foreign body was identified as a leech, Limnatis nilotica, by parasitologic examination. The leech was extracted, and the patient began using topical antibiotic and cycloplegic agents. By the third day after extraction, the patient had no obvious symptoms or signs, except for a limited subconjunctival hemorrhage, and no epithelial defect on the cornea was observed. CONCLUSIONS: Ocular leech infestation should be considered in patients with a history of swimming in streams and lakes. Attention should also be given to ocular leech infestation in the differential diagnosis of ocular trauma with iris prolapse.

Administration, Topical↗
PubMed1997

The leech excitatory peptide, a member of the GGNG peptide family: isolation and comparison with the earthworm GGNG peptides.

A member of the GGNG peptide family was isolated from Hirudo nipponia (leech). GGNG peptides had only been isolated previously from earthworms. The C-terminus structure of the leech peptide, LEP (leech excitatory peptide), was -Gly-Gly-Asn-amide, while that of the earthworm peptides, EEP (earthworm excitatory peptide), was -Gly-Gly-Asn-Gly. LEP exerted 1000-fold more potent activities on leech gut than did EEP-2. On the other hand, EEP-2 was 1000-fold more potent than LEP on the crop-gizzard of the earthworm. Analog peptides of LEP and EEP-2 were synthesized, and the myoactive potency of each analog on the leech and earthworm tissues was compared.

Amino Acid Sequence↗
PubMed1999

Postingestive chemosensation and feeding by leeches.

Distinct chemical cues acting on chemosensory structures on the dorsal lip of bloodsucking leeches activate the entire complement of appetitive and ingestive feeding behaviors. However, it is not known whether the maintenance of ingestion depends on continuous stimulation of these peripheral chemosensors. Leeches of the species Hirudo medicinalis and Macrobdella decora were fed for 2 min on an artificial blood solution containing 150 mM NaCl/1 mM arginine before switching the feeding solution to various experimental mixtures. Leeches did not start to feed on, but continued to ingest solutions in which equiosmolar KCl or lysine substituted for NaCl or arginine, respectively, until sated. In contrast, they rejected water and dropped off the feeding apparatus within 30 s of the exchange. Leeches also detached from the feeding tube when quinine, denatonium, or caffeine were added to the NaCl/arginine solution during an ongoing feeding bout. The duration of ingestion following the switch correlated inversely with the concentration of the drugs (0.1-10 mM). Superfusion of the dorsal lip with high concentrations of the bitter chemicals, while feeding was in progress, had no effect on the duration of ingestion. However, injections of the bitter substances directly into the gut, during a feeding bout, abruptly stopped ingestion. The results suggest that while leeches continue to sample their food once ingestion has begun, secondary chemosensory mechanisms situated downstream from the dorsal lip may be involved in the maintenance of ingestion and the rapid postingestive rejection of noxious foods.

Animals↗
PubMed1994

Serotonin depletion inhibits feeding in carnivorous leeches (Haemopis).

The effect of reserpine on the serotonin content of the central nervous system and the feeding behavior of the carnivorous leech Haemopis marmorata was investigated. Leeches were hand-fed to satiation by presentation of pieces of chicken liver held in forceps for three meals at 4-day intervals prior to and 1 week following three consecutive injections of 100 micrograms reserpine in the crop. A group matched by weight and preinjection food intake was injected with the vehicle in a blind experimental design. Histochemical and chemical determinations showed that reserpine effectively depleted the serotonin content of the animal's central nervous system. Furthermore, the food intake of reserpine-treated animals was significantly less than that of the sham-injected group. However, the depleted animals continued to ingest approximately 40% of the amount consumed during the preinjection period. These results show that reserpine successfully depleted the serotonin in the carnivorous leech H. marmorata and decreased the food intake of this leech species. They suggest that feeding behavior in Haemopis is partially but not exclusively dependent on serotonin and that, in contrast to the sanguivorous leeches, additional factors may be necessary for its regulation.

Animals↗
PubMed2003

Comparing a mechanical device with medicinal leeches for treating venous congestion.

OBJECTIVE: To compare mechanical device therapy to medicinal leech therapy for treating venous congestion. STUDY DESIGN: Fasciocutaneous flaps of 9 x 7-cm (porcine model, n = 11) were elevated and the associated veins clamped for 15 hours. Device-treated flaps (n = 6) were treated with up to 3 devices/flap. Leech-treated flaps (n = 5) were treated with 75 leeches/flap (5 leeches/hour). Treatment evaluation parameters included: blood volume removed, skin color, surface perfusion, tissue oxygen tension, and endpoint histology. RESULTS: No significant differences were seen in blood volume removed, surface perfusion, and oxygen tension. However, significant differences were seen in skin color change over time. Histological assessment showed mild congestion in 5/5 leech-treated flaps and 2/6 device-treated flaps. CONCLUSION: Device therapy was comparable to leech therapy for decongesting a 9 x 7-cm flap over a 15-hour period. However, digital images and significant differences in skin color change over time demonstrate that device therapy promotes more global decongestion versus leech therapy.

Animals↗
PubMed1989

The emergency management of a medicinal leech bite.

Leeches have been used as a medicinal remedy for years untold. Recently, there appears to have been a resurgence in the use of the medicinal leech, Hirudo medicinalis. Presented is the case of a patient who called the emergency department for advice concerning the management of a bleeding leech bite. We discuss briefly the pharmacologically active salivary contents of the leech and an approach to the emergency therapy of a medicinal leech bite.

Animals↗
PubMed1998

Identification and characterization of a myomodulin-like peptide in the leech.

A novel myomodulin-like peptide, GMGALRLamide, has been purified and sequenced from extracts of 1000 medicinal leech nerve cords. Synthetic leech myomodulin-like peptide blocked the specific staining pattern of leech ganglia by the antiserum against Aplysia myomodulin A PMGMLRLamide. Moreover, the synthetic leech myomodulin-like peptide GMGALRLamide showed identical neuronal modulation effect on the giant leech Retzius cell compare to that by the synthetic Aplysia myomodulin A PMGMLRLamide.

Amino Acid Sequence↗
PubMed1996

The role of the leech in medical therapeutics.

Leeching is considered by many to be a discredited medical relic of the past. This view is not justified, since leeches still play an important part in modern medicine, as in microsurgery and in the treatment of patients with post-phlebitic syndrome. Hirudin, the potent thrombin inhibitor of leech saliva, has been cloned and is used in the treatment of cardiological and hematological disorders. In our search for other antihemostatic factors in Hirudo medicinalis saliva, we found inhibitors of platelet aggregation induced by thrombin, collagen, adenosine 5'-diphosphate, epinephrine, platelet-activating factor and arachidonic acid. We purified apyrase (adenosine 5'-triphosphate diphosphohydrolase), which is a non-specific inhibitor of platelet aggregation by virtue of its action on adenosine 5'-diphosphate. We isolated and characterized the platelet-activating factor antagonist and also identified and recovered an inhibitor of coagulation factor Xa from leech saliva. This report summarizes our findings and those of other investigators, as well as the experience of one of us (A.E.) in leech therapy.

Animals↗
PubMed1999

Cloning, characterisation and expression of the alpha-tubulin genes of the leech, Hirudo medicinalis.

We have isolated two alpha-tubulin cDNAs from the leech, Hirudo medicinalis. Both encode putative proteins of 451 amino-acids which differ from each other at only two positions. Southern blotting suggests that there are only two alpha-tubulin genes in the leech. The genes contain two introns and, because of the extremely high homology of the nucleotide sequence from the second intron to the end of the genes, we have inferred that a gene conversion event about 9.5 million years ago has homogenised the Hirudo alpha-tubulin sequences. Using in situ hybridisation to tissue sections, we have shown that the two genes are probably expressed in all neurons of the leech ganglia and that their spatial distribution remains unchanged during neuronal regeneration. The deduced amino-acid sequences of the leech alpha-tubulins show that they have greatest similarity to those from a platyhelminth, echiuran and mollusc with rather less to arthropod alpha-tubulins. The protein sequences of the leech alpha-tubulins have been compared with representatives of those from across all phyla to determine if any specific feature labels certain isotypes of tubulin for neuronal expression.

Amino Acid Sequence↗
PubMed1990

Experimental observations on the specificity of Apatemon (Australapatemon) minor (Yamaguti 1933) (Digenea: Strigeidae) toward leech (Hirudinea) second intermediate hosts.

The infectivity of Apatemon (Australapatemon) minor cercariae to 7 species of freshwater leech was examined under laboratory conditions. The leech species exposed to infection were; Erpobdella octoculata, Helobdella stagnalis, Glossiphonia heteroclita, Glossiphonia complanata, Hemiclepsis marginata, Piscicola geometra, and Theromyzon tessulatum. Five species were capable of acting as second intermediate hosts. Despite this broad specificity only Erpobdella octoculata and Helobdella stagnalis could be considered to show a high degree of compatibility with the parasite. In these 2 leech species more than 38% of the cercariae successfully penetrated and established metacercarial cyst infections. The leeches Piscicola geometra and Theromyzon tessulatum did not become infected. Close parallels were found between the species order of host utilization determined experimentally and that revealed by a range of field surveys in Britain, Eastern Europe and Russia. This suggests that the order of second intermediate host utilization in the natural environment has, at least in part, a physiological basis. The degree to which different leeches are utilized as hosts may relate to the opportunity which they afford for transmission of A. minor to wildfowl definitive hosts.

Animals↗
PubMed1994

Intestinal flora of the medicinal leech Hirudinaria manillensis.

Medicinal leeches are widely used to treat venous congestion in microvascular surgery. Aeromonas hydrophila infection, following application of the leech species Hirudo medicinalis, is a recognized complication. Administration of antibiotics directed at Aeromonas has been successful in minimizing complications of infection from this organism. A different leech species, Hirudinaria manillensis, has recently been introduced for microsurgical use. A study of the enteric content of 30 of these leeches showed that Aeromonas hydrophila was isolated in only 20 percent of animals, while the majority of remaining positive cultures were single and mixed gram-negative rods. All organisms isolated were sensitive to current recommended coverage for Aeromonas hydrophila. This study suggests that the enteric flora of different leech species may be variable and should be carefully characterized, to direct appropriate prophylactic therapy prior to release of new species for clinical use.

Aeromonas↗
PubMed1988

Influence of substrate on the distribution of calcium channels in identified leech neurons in culture.

The Retzius neuron from the leech, growing in culture on the plant lectin concanavalin A as substrate, produces broad flat growth cones and thick bundles of processes. The same cell extends fine straight processes with numerous branches when grown on a laminin-like substrate extracted from leech central nervous system extracellular matrix, referred to as "leech laminin extract." Cells growing on these two different substrates also show marked differences in the pattern of Ca2+ entry following evoked impulses, as detected optically by local changes in absorbance of the Ca2+-sensitive dye arsenazo III. Ca2+ enters the soma and initial segment of Retzius cells grown on both substrates. However, detectable Ca2+ entry only occurs into the processes of cells growing on leech laminin but not of those growing on concanavalin A. Optical recordings of changes in membrane potential made with the voltage-sensitive dye RH 155 taken from cells growing on either substrate indicate that a depolarization initiated in the soma spreads to the most distant processes with little or no distortion in amplitude or time course. This implies that all voltage-sensitive Ca2+ channels in the cell membrane are equally activated by depolarizing stimuli. Therefore, the fact that impulses evoke Ca2+ entry into processes of Retzius cells grown on leech laminin extract but not of cells grown on concanavalin A shows that the nature of the growth substrate can affect the number and distribution of their functional Ca2+ channels.

Animals↗
PubMed2000

Clinical and scientific considerations in leech therapy for the management of acute venous congestion: an updated review.

Any surgical intervention that involves the manipulation of veins, large or small, carries the risk of acute venous congestion. Venous congestion is the product of an imbalance between arterial inflow and venous outflow, and results in the stasis of blood in the tissues that are normally drained by the affected veins. The resultant lack of tissue perfusion causes hypoxia, acidosis, and arterial thrombi formation, which can potentially progress to tissue necrosis and wet gangrene. In the past several decades, the use of leeches (Hirudo medicinalis) has been rediscovered as an effective method of relieving acute venous congestion. This updated review of leech therapy focuses on the use of medicinal leeches in a variety of clinical conditions characterized by acute venous congestion, and points out the experimental use of leeches in other pathological entities. A discussion of the recent scientific findings that explain the possible mechanisms of action of leech therapy is also provided.

Animals↗
PubMed1991

The use of medicinal leeches in microsurgery.

Medicinal leeches have been used to treat a variety of ailments for thousands of years. During the past decade the leech has become valuable for salvaging surgically uncorrectable venous insufficiency which is occasionally encountered after microsurgical free flap and replantation procedures. Leech anatomy and physiology are reviewed. Indications and the technique for application of medicinal leeches is discussed, as well as potential complications of leeching.

Amputation, Traumatic↗
PubMed1991

The use of leeches in distal digital replantation.

Over the past 18 years we have operated on 50 patients who had sustained distal amputation of fingers. Their average age was 30 years (range 2-72 years). Replantation of radial digits on the right hand was most common and the thumb was involved in nearly half the cases in our series. Out of the 50 cases we were able to repair both arteries in 35 patients and only one artery in the other 15. Regarding veins, two were anastomosed in 12, only one in 23 and none in 15 because of the severity of the contusion or the very distal site of replantation. Although early arterial thrombosis usually leaves no solution other than reoperation, venous complications can be relieved by ancillary methods such as leeches which we first used in 1976. We encountered a venous problem in 16 (32%) out of the 50 cases. In three cases a venous anastomosis had been performed, but in 13 others it proved impossible. If congestion was mild, paraungeal or pulpar incision provided some relief because of repeated topical application of heparin and systemic heparinization. If congestion was severe, leeches were used on average for 6 days at a frequency of four to six leeches a day. All cases where leeches were used could be salvaged. One can assess through this sequence that the use of leeches in distal digital replantation has improved the survival rate by 26%.

Adolescent↗
PubMed1998

Leech therapy in the management of acute venous congestion of an infant's lower limb.

We report the successful use of leech therapy in the postsurgical management of an infant with acute venous congestion of an entire lower limb. Two days of constant leech therapy, followed by 5 days of intermittent application, decongested the affected tissues. There were no complications related to the leech therapy, and mild cutaneous hyperpigmentation was the only long-term complication of the acute venous congestion. The volume of the affected tissue may limit the success of leech therapy in cases of acute venous congestion in the limbs of adults. Nevertheless, the use of leeches to manage acute venous congestion of large portions of infants' bodies should be considered when surgical therapies are not feasible.

Acute Disease↗
PubMed1988

Identification of molecules in leech extracellular matrix that promote neurite outgrowth.

The molecular composition of the substrate is of critical importance for neurite extension by isolated identified leech nerve cells in culture. One substrate upon which rapid growth occurs in defined medium is a cell-free extract of extracellular matrix (ECM) that surrounds the leech central nervous system (CNS). Here we report the co-purification of neurite-promoting activity with a laminin-like molecule. High molecular mass proteins from leech ECM purified by gel filtration exhibited increased specific activity for promoting neurite outgrowth. The most active fractions contained three major polypeptide bands of ca. 340, 250 and 220 kDa. Electron microscopy of rotary-shadowed samples showed three macromolecules, one of which had a cross-shaped structure similar to vertebrate laminin. A second six-armed molecule resembled vertebrate tenascin and a third rod-like molecule resembled vertebrate collagen type IV. The most active fractions contained a protein of ca. 1 MDa on non-reducing gels with disulphide-linked subunits of ca. 220 and 340 kDa, with cross-shaped laminin-like molecules. We conclude that a laminin-like molecule represents a major neurite promoting component present in leech ECM. The experiments represent a first step in determining the location of leech laminin within the CNS and assessing its role in neurite outgrowth during development and regeneration.

Animals↗
PubMed1991

Ornatins: potent glycoprotein IIb-IIIa antagonists and platelet aggregation inhibitors from the leech Placobdella ornata.

The purification and characterization of six isoforms of ornatin, potent glycoprotein IIb-IIIa (GP IIb-IIIa) antagonists and platelet aggregation inhibitors are described. These isoforms were purified from whole leech homogenates of the leech Placobdella ornata, a North American leech commonly known as the turtle leech, by trichloroacetic acid precipitation, Sephadex G-50 size exclusion chromatography, GP IIb-IIIa affinity chromatography, and C18 reverse-phase HPLC. Each of the five completely sequenced isoforms, which range from 41 to 52 residues in length, contains the Arg-Gly-Asp (RGD) sequence, a common recognition sequence in adhesion proteins, as well as 6 cysteine residues; the positions of both of these features are conserved in the primary sequences. The amino acid sequences of ornatin isoforms B, C, D, and E are highly conserved, whereas ornatin A2 and A3 are less similar and lack 9 residues at the N-terminus. The ornatins are approximately 40% identical with decorsin, a GP IIb-IIIa antagonist isolated from the leech Macrobdella decora [Seymour, J. L., Henzel, W. J., Nevins, B., Stults, J. T. & Lazarus, R. A. (1990) J. Biol. Chem. 265, 10143-10147]; furthermore, the RGD sequence and 5 out of 6 cysteine residues are maintained in the same relative positions in both decorsin and ornatin. The ornatin isoforms do not exhibit significant similarity to any members of the snake-venom-derived family of GP IIb-IIIa antagonists [Dennis, M. S., Henzel, W. J., Pitti, R. M., Lipari, M. T., Napier, M. A., Deisher, T. A., Bunting, S. & Lazarus, R. A. (1990) Proc. Natl Acad. Sci. USA 87, 2471-2475] except in the RGD region of these proteins. The ornatin isoforms inhibit the binding of GP IIb-IIIa to immobilized fibrinogen with IC50 values ranging over 2.9-5.3 nM; ornatin isoforms A2, C, and E inhibit ADP-induced human platelet aggregation with IC50 values of about 130, 280, and 440 nM, respectively.

Amino Acid Sequence↗