Two-dimensional, M-mode and left atrial velocity echocardiographic measurements in healthy Norwegian-Swedish Coldblooded Trotters.

INTRODUCTION: The Norwegian-Swedish Coldblooded Trotter (NSCT) is an important breed in Norwegian and Swedish harness racing. In spite of this, little is known about its cardiac measurements and factors that may influence these. The aims of this study were to establish reference intervals (RI) for a series of conventional echocardiographic variables, primarily of the left heart, in NSCTs in race training and to evaluate any effects age, gender, estimated body weight (EBW), number of starts and racing performance may have on these. ANIMALS: Sixty-three apparently healthy NSCTs in race training. METHODS: Observational study, convenience sampling. All horses were examined unsedated in their normal stabling environment. Auscultatory and echocardiographic examinations were performed. Means, standard deviations, medians and confidence intervals of the RI limits were used to summarize the data. The relationship between selected echocardiographic variables and age, gender, EBW, racing performance and number of starts were explored using linear regression analyses. RESULTS: Reference intervals were determined for routinely used echocardiographic variables. Data for left atrial velocity were also obtained. Increasing age, number of starts and money earned significantly increased all cardiac measurements. Males had significantly higher ventricular measurements than females. Great vessel measurements increased with increasing EBW. Horses with faster recorded racing times had generally significantly increased cardiac measurements. Clinically insignificant valvular regurgitation was a common finding, particularly at the tricuspid and pulmonary valves. CONCLUSIONS: The RIs described and the factors that may affect these will assist clinicians in interpreting echocardiograms of NSCTs with suspected cardiac disease or poor performance.

The pharmacokinetics of dexmedetomidine administered as a constant rate infusion in horses.

Dexmedetomidine, the most selective α2-adrenoceptor agonist in clinical use, is increasingly being used in both conscious and anaesthetized horses; however, the pharmacokinetics and sedative effects of this drug administered alone as an infusion are not previously described in horses. Seven horses received an infusion of 8 µg dexmedetomidine/kg/h for 150 min, venous blood samples were collected, and dexmedetomidine concentrations were assayed using liquid chromatography-mass spectrometry (LC/MS) and analyzed using noncompartmental pharmacokinetic analysis. Sedation was scored as the distance from the lower lip of the horse to the ground measured in centimetre. The harmonic mean (SD) plasma elimination half-life (Lambda z half-life) for dexmedetomidine was 20.9 (5.1) min, clearance (Cl) was 0.3 (0.20) L/min/kg, and volume of distribution at steady-state (Vdss ) was 13.7 (7.9) L/kg. There was a considerable individual variation in the concentration of dexmedetomidine vs. time profile. The level of sedation covaried with the plasma concentration of dexmedetomidine. This implies that for clinical use of dexmedetomidine constant rate infusion in conscious horses, infusion rates can be easily adjusted to effect, and this is preferable to an infusion at a predetermined value.

Antinociceptive effects of three escalating dexmedetomidine and lignocaine constant rate infusions in conscious horses.

Dexmedetomidine and lignocaine IV are used clinically to provide analgesia in horses. The aims of this study were to investigate the antinociceptive effects, plasma concentrations and sedative effects of 2, 4 and 6 µg/kg/h dexmedetomidine IV, with a bolus of 0.96 µg/kg preceding each continuous rate infusion (CRI), and 20, 40 and 60 µg/kg/min lignocaine IV, with a bolus of 550 µg/kg preceding each CRI, in 10 Swiss Warmblood horses. Electrically elicited nociceptive withdrawal reflexes were evaluated by deltoid muscle electromyography. Nociceptive threshold and tolerance were determined by electromyography and behaviour following single and repeated stimulation. Plasma concentrations of drugs were determined by liquid chromatography and mass spectrometry. Sedation was scored on a visual analogue scale. Dexmedetomidine increased nociceptive threshold to single and repeated stimulation for all CRIs, except at 2 µg/kg/h, where no increase in single stimulation nociceptive threshold was observed. Dexmedetomidine increased nociceptive tolerance to single and repeated stimulation at all CRIs. There was large individual variability in dexmedetomidine plasma concentrations and levels of sedation; the median plasma concentration providing antinociceptive effects to all recorded parameters was 0.15 ng/mL, with a range from <0.02 ng/mL (below the lower limit of quantification) to 0.25 ng/mL. Lignocaine increased nociceptive threshold and tolerance to single and repeated stimulation at CRIs of 40 and 60 µg/kg/min, corresponding to plasma lignocaine concentrations >600 ng/mL. Only nociceptive tolerance to repeated stimulation increased at 20 µg/kg/min lignocaine. Lignocaine at 40 µg/kg/min and dexmedetomidine at 4 µg/kg/h were the lowest CRIs resulting in consistent antinociception. Lignocaine did not induce significant sedation.

Effect of poll flexion and dynamic laryngeal collapse on tracheal pressure in Norwegian Coldblooded Trotter racehorses.

REASON FOR PERFORMING STUDY: Dynamic laryngeal collapse (DLC) associated with poll flexion is a newly diagnosed upper respiratory tract obstructive disorder that causes poor racing performance. OBJECTIVES: To determine if Norwegian Coldblooded Trotters (NCTs) affected with DLC associated with poll flexion differ from normal, elite NCTs based on simple airway mechanics measurements. METHODS: Five normal elite NCTs and 6 NCTs diagnosed previously with DLC underwent treadmill videoendoscopy while tracheal pressures were measured continuously. Alternating head positions were used such that horses were exercised with free head carriage and induced poll flexion at heart rates >200 beats/min. RESULTS: Peak inspiratory tracheal pressures were significantly more negative for horses with DLC compared to the elite horses. This difference was only significant during the exercise phases when the poll region was flexed, P = 0.0015. Head position significantly affected peak inspiratory pressure for both elite and affected horses, P < 0.0001. CONCLUSIONS AND CLINICAL RELEVANCE: Induced poll flexion significantly affected peak inspiratory pressure (PIP) in all horses; however, PIPs were significantly more negative in those affected with DLC. Based upon the tracheal pressure measurements recorded in this study, DLC in NCTs is a severe obstructive upper respiratory tract disorder that is induced by poll flexion.

Leucocytoclastic vasculitis associated with Staphylococcus intermedius in the pastern of a horse.

A pregnant quarterhorse mare became acutely lame as a result of severe swelling of its right hind leg, thought to have been caused by a fracture or a muscle tear. Diagnostic procedures ruled out a traumatic musculoskeletal cause and a physical examination revealed chronic pastern dermatitis ('scratches'/'grease heel'). Histopathological evaluation of biopsy samples from the right hind leg was consistent with a leucocytoclastic vasculitis, and culture yielded Staphylococcus intermedius. The treatment and infectious causes of pastern dermatitis are discussed.

Relationship between urinary albumin and albumin/creatinine ratio during normal pregnancy and pre-eclampsia.

Pre-eclampsia is a serious complication of pregnancy and it is important to detect the condition as early as possible. Albuminuria is an important symptom of pre-eclampsia and repeated urine analyses to screen for the condition are part of the standard antenatal care. The purpose of this study was to investigate whether measurement of the urine albumin/creatinine ratio in spot samples could be a complement to the dipstick method and could reduce the need for 24-h urine collections. Urine samples were collected for 24 h in weeks 12, 24 and 36 of pregnancy from both normotensive women and women who developed hypertension or who had pregnancy-induced hypertension (PIH) when they entered the study. The 24-h albumin excretion was significantly correlated to the albumin/creatinine ratio in all measurements (Pearson correlation coefficient). In week 12, the values were: n = 44, r = 0.964, p < 0.001 (normotensive group) and in the PIH group: n = 8, r = 0.789, p < 0.05. In week 24, the correlation values were r = 1.0 and p < 0.001 in both the normotensive group (n = 41) and in the PIH group (n = 11). In week 36 the correlation values were r = 0.791 and p < 0.001 in the normotensive group (n = 39) and r = 1.0 and p < 0.001 in the PIH group (n = 16). Microalbuminuria was defined as urine albumin excretion higher than 30 mg/24 h and this corresponded to an albumin/creatinine ratio of 2.9. Microalbuminuria was found in three persons in the PIH group and in two persons in the normotensive group. Overt albuminuria (> 300 mg/24 h) was found in one of the 46 normotensive women (2%) and in 3 of the 19 PIH women (16%). In all these women the high albumin values had been detected by using the albumin/creatinine ratio method. In conclusion, it has been found that the albumin excretion in urine correlates significantly to the albumin/creatinine ratio during pregnancy. The urinary albumin/creatinine ratio appears to be a good alternative to the dipstick method and to 24-h urine collections.

Structural analysis of the lipopolysaccharide oligosaccharide epitopes expressed by Haemophilus influenzae strain RM.118-26.

The structure of the lipopolysaccharide of Haemophilus influenzae mutant strain, RM.118-26, was investigated. Electrospray ionization-mass spectrometry on intact lipopolysaccharide, O-deacylated lipopolysaccharide and core oligosaccharides obtained from lipopolysaccharide after mild acid hydrolysis provided information on the composition and relative abundance of the glycoforms. Oligosaccharide samples were studied in detail using high-field NMR techniques. The structure of the major glycoform containing phosphocholine is identical to the Hex2 glycoform described for H. influenzae RM.118-28 [Risberg, A., Schweda, E.K.H. & Jansson, P.-E. (1997) Eur. J. Biochem. 243, 701-707]. A second major glycoform, containing three hexose residues (Hex3), in which a lactose unit, beta-D-Galp-(1-->4)-beta-D-Glcp, is attached at the O-2 position of the terminal heptose of the inner core element, L-alpha-D-Hepp-(1-->2)-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-( 1-->4)-]- L-alpha-D-Hepp-(1-->5)-alpha-Kdo, carries no phosphocholine. Instead this lipopolysaccharide glycoform is partly (40%) substituted by an O-acetyl group linked to the 6-position of the glucose residue in the lactose unit and has the following structure:

Structural analysis of the lipopolysaccharide oligosaccharide epitopes expressed by a capsule-deficient strain of Haemophilus influenzae Rd.

Structural elucidation of the lipopolysaccharide (LPS) of Haemophilus influenzae, strain Rd, a capsule-deficient type d strain, has been achieved by using high-field NMR techniques and electrospray ionization-mass spectrometry (ESI-MS) on delipidated LPS and core oligosaccharide samples. It was found that this organism expresses heterogeneous populations of LPS of which the oligosaccharide (OS) epitopes are subject to phase variation. ESI-MS of O-deacylated LPS revealed a series of related structures differing in the number of hexose residues linked to a conserved inner-core element, L-alpha-D-Hepp-(1-->2)-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp- (1-->4)-]- L-alpha-D-Hepp-(1-->5)-alpha-Kdo, and the degree of phosphorylation. The structures of the major LPS glycoforms containing three (two Glc and one Gal), four (two Glc and two Gal) and five (two Glc, two Gal and one GalNAc) hexoses were substituted by both phosphocholine (PCho) and phosphoethanolamine (PEtn) and were determined in detail. In the major glycoform, Hex3, a lactose unit, beta-D-Galp-(1-->4)-beta-D-Glcp, is attached at the O-2 position of the terminal heptose of the inner-core element. The Hex4 glycoform contains the PK epitope, alpha-D-Galp-(1-->4)-beta-D-Galp-(1-->4)-beta-D-Glcp while in the Hex5 glycoform, this OS is elongated by the addition of a terminal beta-D-GalpNAc residue, giving the P antigen, beta-D-GalpNAc-(1-->3)-alpha-D-Galp-(1-->4)-beta-D-Galp-(1-->4)-D-Glc p. The fully extended LPS glycoform (Hex5) has the following structure. [see text] The structural data provide the first definitive evidence demonstrating the expression of a globotetraose OS epitope, the P antigen, in LPS of H. influenzae. It is noteworthy that the molecular environment in which PCho units are found differs from that observed in an Rd- derived mutant strain (RM.118-28) [Risberg, A., Schweda, E. K. H. & Jansson, P-E. (1997) Eur. J. Biochem. 243, 701-707].

Structural studies of the cell-envelope oligosaccharide from the lipopolysaccharide of Haemophilus influenzae strain RM.118-28.

The structure of the oligosaccharide part of the Haemophilus influenzae RM.118-28 lipopolysaccharide (LPS) has been investigated. The oligosaccharide was obtained from the LPS by mild acid hydrolysis followed by gel-permeation chromatography, and was studied by methylation analysis, NMR spectroscopy and mass spectrometry. The structure of the major compound, which is a hexasaccharide, is proposed as follows. [formula: see text] In the structure, Kdo is 3-deoxy-D-manno-octulosonic acid, PEtn is phosphoethanolamine, PCho is phosphocholine and L,D-Hep is L-glycero-D-manno-heptose. Electrospray-ionization mass spectrometry on O-deacylated LPS obtained after treatment with anhydrous hydrazine gave evidence for the presence of two minor compounds, which show additional substitution of the main structure with phosphate and PEtn, respectively. These substitutions have not been localized.

Electrophonic hearing and cochlear implants.

It has been difficult to explain the good speech understanding obtained by some cochlear implant patients fitted with a single-channel electrode and analog transmissions of the speech signal (Vienna/3M implant). It has also been difficult to explain the variation in results reported by different groups using the same implant. One hypothesis asserts that the above differences can be explained by the observation that electric stimulation with an implanted electrode might result in two different auditory sensations, the first resulting from the stimulation of the remaining hair cells (electrophonic component) and the second from the electric stimulation of the auditory nerve (electro-neural component). The two sensations are very different. As a result of different definitions of total deafness (functional or threshold definition), patients with remaining hair cells are operated on by some groups, but not by other groups. Some published results from different studies are discussed with reference to the above hypothesis and the possible consequences for the selection of the patients, the use of extra- or intracochlear electrodes, and the selection of the speech coding strategy are discussed.

A case material with post lingual severe hearing loss and communication handicap.

The analyses have given some general clues to the therapeutic handling of these patient categories: 1. The A and B groups can be labelled "hearing" with clearly useful residual hearing. 2. The patients in the C group, as a rule, are utilizing very little from acoustic speech stimulation, mostly the prosodic information. Several patients in this group are possible implant candidates, and it is reasonable to expect that (with a suitable stimulus device and a suitable application of this) the patients could get an additional support during speech reading, so that they function as the B group. Tactile devices are also an alternative or a supplement for this group, and a pilot study on six patients is in progress in the department in cooperation with the Department of Speech Communication at the Royal Institute of Technology. 3. The patients within the A and B groups will in the first place be offered additional functional training programmes (prosodic training, audio-visual training and possibly vibration training) and, as an ultimate alternative a social activation in group therapy may be considered. Some patients in these groups might also be candidates in the future for an extra cochlear implant.

Rehabilitative procedures in sensorineural hearing loss. Studies on the routine used.

The effect of different treatment programs in audiological rehabilitation was evaluated. The speech intensity at which subjects with high frequency hearing loss correctly perceived 50% of the key words in sentences was measured in quiet and in noise, with and without a hearing aid and with and without simultaneous speech reading. No statistically significant difference in audiovisual speech perception ability was found between subjects receiving no training, subjects receiving a 6-hour information course, or a 3-week intensive training in auditory and audiovisual speech perception. Large differences in the degree of hearing aid usage was found, however, between the three treatment groups. An analysis of the individual results from the speech test used showed that some subjects improved with the use of a hearing aid, whilst others deteriorated. The degree of hearing aid usage was considerably influenced by the measured effect of the hearing aid treatment. Our findings stress the need for an objective test by which to measure the effect of hearing aid fitting. As a result of the reported study a series of experiments have been started with the aim of obtaining a better understanding of the audiovisual speech perception process. These studies are based on an information-processing model for speech perception. Particular attention is devoted to the importance of the prosodic information in the auditory speech signal.

Sleep apnea syndrome caused by acromegalia and the treatment with a reduction plasty of the tongue. Case report.

Obstructive sleep apnea syndrome was every likely caused by an enlarged tongue in a 60-year-old man with acromegalia. The diagnosis was confirmed by polygraphic sleep recordings and by roentgenologic examination. The patient was treated with a tongue-reduction plasty which gave him good subjective relief and better sleep. A whole night polygraphic sleep recording showed a couple of hours of normal sleep without apneas or arousals. The last part of the night was, however, still disturbed by several apneas with concomitant arousals.

Sleep apnea syndrome--an alternative treatment to tracheostomy.

Two patients with obstructive sleep apnea syndrome had polygraphic recordings demonstrated upper airway obstruction and sleep with extremely short sleep latency, severely disturbed nightsleep resulting in sleep deprivation, and excessive daytime sleepiness. Radiological investigation showed the upper airway obstruction to be caused by the tongue falling back occluding the pharynx. Nasopharyngeal intubation relieved the symptoms. The patients were trained to perform this treatment themselves every night, demonstrating that this treatment is an attractive alternative to the conventional tracheotomy.

Normal sleep pattern analyzed statistically and studied by color "dormograms".

Polygraphic sleep recordings were made from 46 healthy adult volunteers during 159 nights and evaluated visually. Sleep stages for each 30 sec epoch were entered into a computer data base from which plots of individual nights, as well as color "dormograms" and/or statistical parameters for a set of nights, could be produced. The total mean dormogram in which all the nights were synchronized at sleep onset revealed a dominant sleep pattern, which was found to be very stable even for subgroups. Synchronizing at the beginning of the second REM period allowed the pattern for the last half of the nights to appear more clearly. A large number of different sleep parameters were calculated for each night and statistically analyzed. On the basis of these results a normal "mean" sleep pattern could be reconstructed and related to other studies of normal sleep patterns.

Requirements on speech processing hearing aids for the profoundly deaf, some preliminary remarks.

Many severely hard of hearing and profoundly deaf persons seem to get very little help from an ordinary hearing aid. This observation has prompted the development of tactile speech processing aids. These aids should however only be used if it can be shown that the subject has no useful residual hearing. In the case of a profound hearing loss the audiogram might in some cases show tactile sensations in the ear. To get a better estimation of the remaining auditory capacity experiments have been made with frequency discrimination measurements, and with speech tests consisting of rhyming word pairs. Results from these different tests are summarized in relation to an audiogram classification system. Two tactile speech processing aids are described. Evaluation studies with these aids show positive results but these results must be compared with the results that can be obtained with ordinary hearing aids and different types of auditory speech processing hearing aids. The possibility to use extreme auditory recording must also be studied. In this case the transmitted signal is not speech-like and it is possible that this limits their usefulness. Experiments with this type of aids might however give valuable information about how the human perceptual systems process signals derived from the original speech signal.

Evaulation of the effect of fosazepam (a new benzodiazepine), nitrazepam and placebo on sleep patterns in normal subjects.

The nocturnal sleep of eight healthy young volunteers was studied after placebo, Fosazepam 100 mg and Nitrazepam 10 mg. Overall results were very similar after the two drugs. During drug periods there was less of sleep Stages I, III + IV and REM, compensated by an increase in Stage II. The decrease in SWS (III + IV) persisted during the withdrawal periods. There was also an increase in Stage I during Fosazepam withdrawal, whereas the percentage of other sleep stages returned to normal. Sleep quality was reported to be slightly better and morning drowsiness, as well as hangover effects, were said to be less pronounced after Fosazepam than after Nitrazepam.