Vesicular storage of glycine in glutamatergic terminals in mouse hippocampus.

Glycine acts as a neuromodulator to regions rich in glutamatergic synapses, such as the forebrain. However, recent evidences for synaptic release of glycine in hippocampal cultured neurons and synaptosomes argue for the existence of functional glycinergic synapses in the hippocampus. It is well established that GABA and glycine act in concert at inhibitory synapses, while the existence of synapses which utilize both glutamate and glycine is less common. The purpose of the present study was to investigate the distribution of glycine and its role in hippocampal neurotransmission. Using immunohistochemistry, we demonstrate that vesicular glycine is preferentially stored in glutamatergic, rather than GABAergic presynaptic terminals. Using the sniffer patch technique, we found that glycine could be released upon presynaptic activity. Furthermore, using whole-cell patch-clamp recordings, we show for the first time the presence of a postsynaptic strychnine-sensitive chloride current in response to presynaptic stimulation. The small amplitude of this current is likely due to the paucity of postsynaptic glycine receptors rather than a low level of glycine release. Taken together, our results suggest that glycine is stored in glutamatergic presynaptic terminals. It is likely that the major role of glycine that is released from presynaptic terminals is to modulate N-methyl-d-aspartate receptor function but may also play a role in decreasing neuronal excitability by opposing glutamatergic neurotransmission in pathological states such as epilepsy or ischemia.

[The sympatho-adrenergic stress reaction in ear surgery using various anesthesia technics]. / Die sympathoadrenerge Stressreaktion bei Ohroperationen unter verschiedenen Anästhesietechniken.

The aim of the present study was to investigate the effects of various anaesthetic procedures on the endocrine stress responses during ear microsurgical operations. Simple mastoidectomies, radical mastoidectomies and tympano plastics were carried out in 49 patients under the following randomised anaesthetic procedures: Group 1 halothane anaesthesia and retroauricular infiltration anaesthesia with lidocaine and ornipressin (n = 14), Group 2 fentanyl anaesthesia and retroauricular anaesthesia with lidocaine and ornipressin (n = 10), Group 3 fentanyl anaesthesia and retroauricular infiltration anaesthesia with lidocaine and epinephrine (n = 14), and Group 4 retroauricular infiltration anaesthesia with prilocaine and epinephrine (n = 14). The plasma levels of epinephrine, norepinephrine, glucose, lactate and free glycerol were measured in addition to mean arterial pressure (MAP) and heart rate (HR) immediately before anaesthesia, 10 minutes after skin incision, 10 minutes after having started bone drilling, at the end of the operation and 3 hours after operation. All data were subjected to covariance analysis including the age factor. Plasma catecholamine concentrations remained within the normal range during the investigation in patients subjected to general anaesthesia (Groups 1-3). Plasma catecholamines (epinephrine and norepinephrine) increased significantly in Group 4 (retroauricular infiltration anaesthesia). There were no group variabilities with regard to MAP and HR. The plasma levels of epinephrine and norepinephrine demonstrate a direct response to stress followed by a secondary change in glucose, lactate and free glycerol. The beneficial effect of general anaesthesia is documented by normal plasma levels of epinephrine and norepinephrine throughout the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Plasma concentrations of lidocaine and prilocaine following infiltration anesthesia in otorhinolaryngologic surgery]. / Plasmakonzentrationen von Lidocain und Prilocain nach Infiltrationsanästhesien bei Operationen im Hals-Nasen-Ohren-Bereich.

UNLABELLED: Infiltration anaesthesia is still relevant for the surgical treatment of patients in otorhinolaryngology. The injection of local anaesthetics in well vascularised areas constantly causes the danger of high plasma concentrations of local anaesthetics combined with undesirable side effects. In our study we tried to determine the development of plasma concentrations of local anaesthetics in patients scheduled for routine tonsillectomies and tympanoplasty. MATERIALS AND METHODS: In 45 patients the development of plasma concentrations was measured immediately after the injection at short intervals; the samples were obtained between 1 minute and 60 minutes after the first injection. Group 1: Lidocaine 0.5% with epinephrine (1:200,000) 15-20 ml for tonsillectomy (n = 18). Group 2: Lidocaine 0.5% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). Group 3: Prilocaine 1% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). For tactical reasons infiltration anaesthesia for the patients of group 2 was - in addition to general anaesthesia - applied by the otorhinolaryngologist, whereas the patients of groups 1 and 3 were operated exclusively under local anaesthesia. RESULTS: Within the first minute after the initial injection plasma concentrations of the local anesthetic increased close to toxic threshold levels that are associated with undesirable systemic side effects. In the patients of group 1, who underwent tonsillectomy, plasma concentrations of 4-7 micrograms/ml were found during the first minute. The highest average values always appeared within the first five minutes: group 1 2.07 micrograms/ml, group 2: 0.45 micrograms/ml, and group 3: 1.15 micrograms/ml. DISCUSSION: With infiltration anaesthesia in well vascularised areas it may happen that there are--mainly in the early stage--high plasma concentrations of the applied substances, although the total dose was below the known maximum. Despite careful technique (repeated aspiration test in two levels) at least partial intravascular injections are apparently not always avoidable according to the pharmacokinetic data. Our results demonstrate that in addition to a safe peripheral venous line and prophylactic oxygen therapy, intraoperative monitoring of blood pressure, heart rate, electrocardiogram and verbal patient monitoring is of advantage in this group of patients. In our opinion the "standby function" of an anaesthesiologist can avoid severe complications.

[Effect of nitrous oxide inhalation anesthesia on sero-mucous secretions of the tympanum]. / Der Einfluss der Lachgas-Inhalationsnarkose auf das Sero-Muko-Tympanon.

It is known that nitrous oxide anaesthesia results in an increase of the middle ear pressure. The aim of this project was to find out, if an increase of the middle ear pressure due to high concentration of nitrous oxide could lead to evacuation of the seromucoid secretion through the Eustachian tube. In 37 children (64 ears) scheduled for myringotomy, tympanograms were performed immediately before and during anaesthesia, the middle ear fluid was confirmed by myringotomy and, if any, sucked out. Both the comparison of the tympanograms prior and during the anaesthesia and the results of myringotomy led to a conclusion, that, in general, nitrous oxide anaesthesia induces no evacuation of middle ear fluid via the Eustachian tube.

[Kimura' disease with localization at the neck (author's transl)]. / Kimurasche Krankheit mit Lokalisation am Hals.

This disease is discussed in the past mostly in the dermatological literature, the ENT specialist is little aware of its existence. The condition is characterized by subcutaneous, painless nodules occurring most frequently in the region of the ear, parotid gland, cheek and lateral neck. The lesion must be differentiated from disease of the lymph nodes, especially malignant tumours. The pathologic diagnosis is based upon a hyperplasia of angiolymphatic tissue and marked blood eosinophilia. The prognosis appears to be favourable. A case is presented together with the clinical picture and histopathological findings. The differential diagnosis and treatment are discussed.

Ossicular reconstruction in the absence of stapedial crura.

The reconstruction of the ossicular chain when the stapes crura are absent presents a difficult problem in achieving satisfactory functional results in the treatment of chronic oitis media by tympanoplasty. When the malleus handle is present, the cases have been treated mostly by repositioning part of an incus or a piece of cartilage between the malleus handle and the mobile footplate. The problem becomes more difficult in tympanoplastic management of old radical cavities with no ossicules apart from the stapes footplate. Apart of repositioning a part of incus or a cartilage strut between the fascial graft and the footplate, the author has tried, in the management of these cases during the last 3 years, a new "umbrella type" of prosthesis made entirely of tragal cartilage. This prosthesis enables a good resting surface for the new tympanic membrane and the hearing improvement seems to be greater than that resulting from other types of ossicular reconstruction.