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At least 19 recordsLinked to original sources
PubMed1976

The connective tissue coverings of leech peripheral nerves: anatomical evidence for the absence of cerebrospinal fluid in the leech.

The central nervous system of Hirudo medicinalis is contained within a blood vessel, the ventral longitudinal sinus, but the nervous system is separated from the blood by the visceral endothelium. The visceral endothelium possesses many pinocytotic vesicles and basal infoldings and thus appears active whereas the parietal endothelium appears inactive. The junction between the visceral and parietal endothelia is abrupt. Peripheral nerves in this animal, as in vertebrates, are covered by endoneurium, perineurium, and epineurium. The endoneurium is continous with the fibrous tissue of the segmental ganglia. The perineurium, consisting of a single layer of flattened cells that surrounds the peripheral nerve like a sleeve, is not continuous with the endothelium of the ventral sinus, but is separated from it by 5-10 microns. Therefore, at the point where the peripheral nerve joins the segmental ganglion, the extracellular spaces of the central nervous system, the peripheral nervous system, and the body wall are all confluent. Thus, there are only two compartments of the extracellular space in the leech: the blood, which is enclosed by the endothelia of the coelomic sinuses, and the extracellular fluid of the body, which includes the extracellular fluid of the nervous system. There seems to be no equivalent of cerebrospinal fluid in the gnathobdellid leech.

Animals↗
PubMed1992

Aeromonas hydrophila infections following use of medicinal leeches in replantation and flap surgery.

Aeromonas hydrophila infections are a recognized complication of postoperative leech application, and can occur with measurable frequency in populations of patients treated with leeches. We review 11 previously reported leech-related Aeromonas infections and analyze seven unreported cases. These infections range from minor wound complications to extensive tissue loss and sepsis. Often, these infections followed leech application to tissue with questionable arterial perfusion. Onset of clinical infection in these patients ranged from within 24 hours of leech application to 10 days or more after leech application. Late infections may represent bacterial invasion from colonized necrotic tissue. Based on these observations, we recommend that leech applications be restricted to tissue with arterial perfusion to minimize contamination of necrotic tissue. We also recommend that patients treated with leeches receive antibiotics effective against Aeromonas hydrophila before leech application. Patients treated with leeches and discharged with eschars or open wounds might benefit from oral antibiotic therapy until wound closure. These precautions may minimize or eliminate this complication of leech use.

Adolescent↗
PubMed1991

Serotonin in the leech central nervous system: anatomical correlates and behavioral effects.

1. Serotonin is sequestered by a limited population of identified neurons in the 32 ganglia of the leech nervous system. A major fraction of the serotonin in each ganglion is contained in the paired Retzius cells, colossal effector neurons whose size varies longitudinally. The 5 other classes of identified serotonin-containing neurons, one effector cell and 4 interneurons, are approximately twice as numerous in anterior as in posterior ganglia. 2. We dissected 6 longitudinal samples from the ventral nerve cords of hungry Hirudo medicinalis, and measured their serotonin content using high pressure liquid chromatography with electrochemical detection. A consistent neurochemical pattern emerged in which segmental ganglia 2-4 had the highest quantity of serotonin: 18.51 pmol per ganglion. The anterior cerebral ganglion contained 14.78 pmol, and the content of the 4 posterior samples, segmental ganglia 7-10, 12-15, 17-20 and the caudal ganglion, decreased continuously from 16.35, 15.08, 10.75 to 2.51 pmol per ganglion, respectively. Morphometric analyses indicated that this pattern of ganglionic serotonin correlated primarily with longitudinal variations in the number of serotonin neurons per ganglion and secondarily with volume of the Retzius cells. Retzius cell volume correlated highly with the mass of their innervated body segments both of which are largest in mid-body domains. 3. Serotonin expresses leech feeding, and its ganglionic levels are a potentially useful index of behavioral state. We measured serotonin in the ganglionic samples from hungry and satiated leeches. The samples from recently fed animals contained 28% less serotonin than those from hungry ones. The amounts of serotonin in the cerebral and all the segmental samples from satiated leeches were significantly lower than equivalent samples of hungry animals. A similar pattern of depletion was seen in leeches which fed for a prolonged period (90 to 120 min) rather than the normal period of 30 min. 4. The effects of ingestion on serotonin-containing neurons was examined with the glyoxylic acid-induced histochemical fluorescence. The levels of fluorescence in all serotonin neurons in fed leeches were consistently lower than those in equivalent neurons in hungry animals, corroborating the ganglionic decrease in serotonin in satiated leeches. 5. To examine effects of body wall distension on serotonin levels, hungry leeches were fed to satiation, and half of them were relaxed by removing their distending blood meals. After 6 weeks, ganglionic serotonin in leeches with relaxed bodies was 21% higher than in those with distended bodies. 6. Ingestive behavior depletes serotonin from leech neurons and body wall distension appears to interfere with its synthesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Leeches: controlled trial in venous compromised rat epigastric flaps.

Leeches were studied for their efficacy to improve survival of venous compromised rat skin flaps. In 22 rats, bilateral epigastric island flaps were created and subjected to 6 h of venous occlusion. One flap in each animal was randomised to leech treatment, while the contralateral flap served as its own control. Flap survival, leech feeding time, weight gained by the leech and bleeding time from leech bites were measured. The area of flap survival was significantly increased in leech treated flaps compared to contralateral controls (n = 22 pairs, p = 0.03; Wilcoxon signed rank test). Weight gained in the feeding leech averaged 1.3 +/- 0.2 g (n = 18). Leech feeding time was 107 +/- 13 min (n = 18). Bleeding time from each leech bite averaged 79 +/- 12 min (n = 18). Hence, the extent of flap necrosis resulting from venous impairment can be partly diminished by leech treatment until definitive surgical venous revascularisation.

Animals↗
PubMed1991

Leech therapy: when once is not enough.

Venous congestion is a constant threat in the survival of free flaps, pedicled flaps, tissue replantations and traumatized tissue. Leech therapy has proved effective in salvaging much of these compromised tissues. To be effective, leeches must be both readily available and hungry, requirements not always easily met. Our investigation seeks to establish a means to return sated leeches to their previous unfed, hungry state for reuse. Sated leeches were purged of their blood meals by placement in 3% hypertonic saline or by gentle finger pressure, then exposed to serotonin 0 microM (control), 10 microM, 30 microM or 90 microM for 20 min. Subsequent rebiting/refeeding was observed and analysed. Leeches bathed in serotonin rebit or reattached at nearly four times the rate of unexposed leeches; 30% vs 8% respectively. Biting, however, is not refeeding. Overall, 41 leeches were treated with serotonin with four (10%) refeeding. Those that refed consumed a significantly smaller blood meal than the initial feeding; 50% +/- 47% SD vs 348% +/- 143% SD of original body weight. None of the control group refed. As a method for routinely reusing leeches, serotonin bathing cannot be recommended. In the immediate postoperative period with the sudden emergence of venous congestion requiring leech therapy, but with an inadequate number available, this 20% [corrected] refeed rate after 10 microM serotonin exposure could potentially determine the success or failure of the flap/replantation until fresh leeches are made available.

Animals↗
PubMed1992

The use of leeches for treatment of venous congestion of the nipple following breast surgery.

The medicinal leech, Hirudo medicinalis, played a central role in the evolution of medieval and folk medicine. Today, for the first time in history, the leech actually has a real and valuable purpose in medicine as a useful adjunct for the plastic surgeon: It provides relief of venous congestion. For over 2000 years, leeches were needlessly applied for a multitude of maladies as an adjunct to blood-letting. Their use in Europe peaked between 1830 and 1850, however, shortages led to a subsequent decline in leech application. Today there is a real clinical use for leeches which had led to a resurgence in their use in plastic surgery. Plastic surgeons use leeches in microsurgery to salvage congested flaps, whose viability is uncertain due to venous congestion. We present our experience with two patients where leeches were used to treat isolated venous engorgement of the nipple following breast surgery. Leech therapy is painless, well tolerated, and does not result in significant scarring. Prompt initiation of treatment is mandatory and produces dramatic resolution of venous congestion.

Adult↗
PubMed1992

Postprandial Aeromonas hydrophila cultures and antibiotic levels of enteric aspirates from medicinal leeches applied to patients receiving antibiotics.

Increasing use of medicinal leeches has been accompanied by increasing numbers of reports of Aeromonas hydrophila infections after leech application on or near damaged tissue. We examined the enteric contents of postprandial leeches after their application to patients receiving antibiotics. We found measurable levels of antibiotic in the leech enteric contents, and in leeches applied to patients receiving an antibiotic effective against Aeromonas hydrophila, there was a significant decrease in positive Aeromonas enteric cultures. Suppression of leech enteric bacteria by antibiotic administration to the patient may be an effective strategy to prevent invasive infection by Aeromonas hydrophila as well as bacterial colonization of devitalized tissue that could be the source of late infection. Clinical studies will be required to clarify whether suppression of leech enteric flora results in a decrease in infections associated with leech use.

Aeromonas hydrophila↗
PubMed1990

Leech therapy and bleeding wound techniques to relieve venous congestion.

Temporary restoration of capillary skin blood flow can be established by using leeches or by the creation of a dermal wound and the promotion of continued bleeding from the wound site in a flap with venous occlusion. An increasing restoration of capillary flow occurred with initial application of the leech and tended to exceed other techniques of restoring flow. However, all techniques of exsanguination, including leech therapy, restored very low perfusion over a two-hour course of therapy for a volume of tissue simulating a distal finger replant. The temporary increase in flap perfusion with a single leech application was greatest during the feeding activity of the leech and tapered off after the leech was satiated, to approximate flows achieved with local heparin injection and a punch wound.

Animals↗
PubMed1988

Use of leeches in plastic and reconstructive surgery: a review.

Leeches possess properties that make them uniquely able to assist with venous compromised tissue. Their saliva contains an anticoagulant and a histamine-like vasodilator that promote local bleeding, a local anesthetic, and hyaluronidase that promotes the local spread of the other leech salivary secretions into the wound/bite. In addition, active pharyngeal peristalsis further promotes the egress of venous blood. Resurgence in the use of leeches has been stimulated by Upton in the United States and Mahaffey in Europe. Currently, leeches are used at many microsurgical centers to provide critical venous outflow for compromised tissue replantations and transfers that might otherwise be unsalvageable. As the use of leeches becomes more widespread, knowledge of leech biology and physiology is important. This review reports on Hirudo medicinalis, the species used most often medically in Europe and the United States.

Animals↗
PubMed1988

Attachment to an endogenous laminin-like protein initiates sprouting by leech neurons.

Leech neurons in culture sprout rapidly when attached to extracts from connective tissue surrounding the nervous system. Laminin-like molecules that promote sprouting have now been isolated from this extracellular matrix. Two mAbs have been prepared that react on immunoblots with a approximately equal to 220- and a approximately equal to 340-kD polypeptide, respectively. These antibodies have been used to purify molecules with cross-shaped structures in the electron microscope. The molecules, of approximately equal to 10(3) kD on nonreducing SDS gels, have subunits of approximately equal to 340, 220, and 160-180 kD. Attachment to the laminin-like molecules was sufficient to initiate sprouting by single isolated leech neurons in defined medium. This demonstrates directly a function for a laminin-related invertebrate protein. The mAbs directed against the approximately equal to 220-kD chains of the laminin-like leech molecule labeled basement membrane extracellular matrix in leech ganglia and nerves. A polyclonal antiserum against the approximately equal to 220-kD polypeptide inhibited neurite outgrowth. Vertebrate laminin did not mediate the sprouting of leech neurons; similarly, the leech molecule was an inert substrate for vertebrate neurons. Although some traits of structure, function, and distribution are conserved between vertebrate laminin and the invertebrate molecule, our results suggest that the functional domains differ.

Animals↗
PubMed1991

Extracellular matrix molecules in development and regeneration of the leech CNS.

As neurons grow to their targets their processes elongate, branch and form specialized endings into which are inserted appropriate ion channels. Our aim has been to analyse the role of the extracellular matrix molecules laminin and tenascin in inducing growth and in determining the form and physiological properties of growing neurites. A preparation in which development and regeneration can be followed at the cellular and molecular level in the animal and in tissue culture is the central nervous system (CNS) of the leech. In leech extracellular matrix (ECM) both laminin and tenascin are present; the molecules are structurally similar but not identical to their vertebrate counterparts. Tenascin extracted from leech ECM shows a typical hexabrachial structure whereas laminin shows a typical cruciform structure in rotary shadowed preparations. Leech laminin purified by means of a monoclonal antibody is a molecule of about 1000 kDa, with a polypeptide composition of 340, 200, 180 and 160 kDa. Substrates that contain tenascin or laminin produce rapid and reliable outgrowth of neurites by identified cells. A remarkable finding is that the outgrowth pattern produced by an individual neuron depends in part on its identity, in part on the substrate upon which it is placed. For example, a Retzius cell grows in a quite different configuration and far more rapidly on laminin substrate than does another type of neuron containing the same transmitter (serotonin); and the pattern of outgrowth of the Retzius cell is different on laminin and on the plant lectin Con A (concanavalin A). Thus Con A induces the growth of processes that are shorter, thicker, more curved and contain fewer calcium channels than those grown on laminin. To determine whether laminin can also influence neurite outgrowth in the animal, immunocytological techniques have been used to follow its distribution in the extracellular matrix of normal, developing and regenerating leech CNS. In adult leeches neuronal processes in the CNS are not in contact with laminin which is confined to the surrounding extracellular matrix. In embryos however, laminin staining appears between ganglionic primordia along the pathways that neurons will follow. Similarly, after injury to the adult CNS, laminin accumulates at the very sites at which sprouting and regeneration begin. How the laminin becomes redistributed to appear in the region of injury has not yet been established. Together these findings suggest a key role for laminin and for other extracellular matrix molecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Saxitoxin differentiates between two types of Na+-dependent potentials in the Retzius cell of hirudinid leeches.

The effects of tetrodotoxin (TTX) and saxitoxin (STX) on the action potentials recorded in Ca2+-free solution in the absence of Ca2+ and K+ currents were investigated in the Retzius cell of three hirudinid leech species (Hirudo medicinalis, Macrobdella decora and Poecilobdella granulosa) and in the glossiphoniid leech Haementeria ghilianii. In the four leech species, stimulation of the Retzius cell in the presence of 25 mmol l-1 tetraethylammonium chloride (TEA), 3 mmol l-1 4-aminopyridine (4-AP) and 2mmol l-1 Mn2+ evoked prolonged action potentials consisting of an initial fast-rising spike followed by a plateau lasting several hundreds of milliseconds. The amplitude and duration of both components of action potentials recorded under these conditions were dependent on [Na+]o. In the hirudinid leeches the initial spike was unaffected by TTX and STX whereas the plateau was selectively blocked by micromolar concentration of STX. In Haementeria both the initial spike and the subsequent plateau were sensitive to nanomolar concentrations of STX and TTX with an estimated ED50 of approximately 20 nmol l-1 for inhibition of Vmax of the fast spike. The results suggest that there are two types of ionic currents mediating the two distinct components of Na+-dependent action potentials in the Retzius cell: (1) a fast-inactivating one, presumably underlying the normal spike which is TTX- and STX-resistant in hirudinid leeches but sensitive to both agents in Haementeria and (2) a low-threshold, prolonged current which underlies the plateau recorded from these cells in the absence of Ca2+ and K+ currents and which is selectively blocked by STX in hirudinid leeches but sensitive to both STX and TTX in Haementeria. It is likely that the variable kinetic and pharmacological properties that characterize the various Na+ potentials in these identified homologous neurones may be of functional significance and result from differences in the molecular structure of their Na+ channels.

4-Aminopyridine↗
PubMed1989

[Epistaxis caused by leeches].

Among the conditions which can cause epistaxis are intranasal or nasopharyngeal foreign bodies. A living foreign body, or parasite, in the nose or nasopharynx is rare in western countries, but in other parts of the world is a fairly common cause of epistaxis. In the past 5 years 17 cases of epistaxis due to infestation with leeches were treated in our 2 departments. In 14 patients, 9-27 years old, the complaint was of recurrent episodes of mild epistaxis and blood-spitting several days before admission. 3 patients were admitted hemorrhaging profusely from the nose and mouth. Examination showed a green-brown mass protruding from the nasopharynx behind the soft palate, which is every case was a blood-engorged leech. Treatment consisted of removing the leech by applying a forceps to the middle of the leech's body and giving a quick pull. Bleeding ceased immediately after removal of the leech. All the patients had drunk water from brooks, streams or fresh water lakes. Therefore, in areas in which leeches are present only boiled or filtered water should be drunk.

Adolescent↗
PubMed1989

Sustained bleeding after a leech bite in the apparent absence of hirudin.

The bite of the medicinal leech bleeds for many hours. For decades it has been assumed that the remarkably prolonged bleeding time of a leech bite wound is due to hirudin, a specific anti-thrombin secreted by the leech during feeding. By measuring haematological parameters of blood oozing from a leech bite wound on 15 different occasions in 7 human volunteers, we demonstrate that the hirudin-sensitive coagulation parameters, including thrombin-induced platelet aggregation, are prolonged for only 15 min, after which they return to normal. This suggests that excess hirudin secreted by the leech is washed out during this period. However, bleeding from the leech bite wound persists for a mean of 10 h. Platelets in smears of exuding blood show no evidence of spontaneous aggregation, but in vitro platelet aggregation can be induced by exogenous collagen at any time. In view of sustained bleeding in the apparent absence of hirudin, attention is focussed onto an unsuspected factor or factors which may better explain the prolonged bleeding phenomenon.

Animals↗
PubMed1989

Quantitative fluorimetric effects of leeching on a replanted ear.

Leeching is used to relieve venous congestion in microscopically replanted tissues. A quantitative description of the effects of leech application on tissue perfusion has not been reported. We report a case of an ear replantation in which venous congestion was consistently improved with leeching. In four instances, quantitative fluorimetry, which indicated impaired circulation and prompted leech application, showed restoration of normal circulation patterns following leech application. The fluorometric studies suggested that arterial inflow improved and venous congestion was relieved.

Adult↗
PubMed1992

Differential effects of serotonin depletion on sensitization and dishabituation in the leech, Hirudo medicinalis.

The goal of these experiments was to test the hypothesis that serotonin (5-HT) is involved in facilitation of the shortening reflex in the leech Hirudo medicinalis. For this reason, we have used the toxin 5-hydroxytryptamine (5,7-DHT) to deplete serotonin from the nervous systems of intact leeches and have assessed the effect on early facilitation, dishabituation, and sensitization of the touch-elicited shortening reflex using behavioral procedures previously developed in our lab (Boulis and Sahley, 1988). We find that 5,7-DHT lesions completely attenuate early facilitation and sensitization but only reduce dishabituation of the touch-elicited shortening reflex. Histological analyses of the ganglia from these leeches using glyoxilic acid staining procedures revealed an absence of staining in the Retzius cell of experimental leeches. All other serotonin-containing neurons showed glyoxilic acid staining comparable to that observed in the control leeches.

5,7-Dihydroxytryptamine↗