The distribution of nerve fibres immunoreactive for vasoactive intestinal peptide, calcitonin gene-related peptide, substance P and dopamine beta-hydroxylase in the normal equine larynx

The autonomic innervation of the mammalian respiratory system is complex, and involves a wide variety of peptide and non-peptide neurotransmitters which will have an important role in normal laryngeal function and the response to disease. This innervation has been partially described in the horse airway and lung, but there is no information on the equine larynx. This paper describes the expression and distribution of nerve fibres immunoreactive for vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), substance P (SP) and the adrenergic enzymatic marker dopamine beta-hydroxylase (DBetaH) in the mucosa of the equine larynx. The overall relative density of nerve fibres immunoreactive for the different antigens was VIP>CGRP>SP>DBetaH. There were differences in the distribution of nerve fibre types, although each antigen was found in nerve fibres adjacent to blood vessels and mucous glands. VIP -like immunoreactivity (VIP -Li) was particularly extensive in association with mucous glands. SP - and CGRP -like immunoreactivity (SP -Li, CGRP -Li) were also seen close to the epithelium, with occasional nerve fibres coursing beneath and between the epithelial cells. Fragments of SP -Li and CGRP -Li fibres were also present in large nerve fibre bundles and ganglionic cell clusters, but not in the neurons themselves. The density of nerve fibres immunoreactive for DBetaH was very low and restricted to blood vessels and mucous glands. There was marked variation in the density of nerve fibres at the different sites, with the greatest density, particularly for VIP, over the arytenoid cartilage. Immunoreactive nerve fibres were less plentiful over the epiglottis, and the density of all types of nerve fibres was low over the cricoid cartilage. Overall VIP -Li nerve fibres were the most plentiful.     

Investigation and management of a cluster of cases of equine retained fetal membranes in Highland ponies

Four at-risk Highland ponies on the same premises all retained their fetal membranes in the same breeding season. The ponies were treated with a combination of oxytocin, infusion and distension of the allantochorionic sac with fluid, gentle traction in one case, and supportive therapy. The possible causes of the condition were investigated with clinicopathological tests and analyses of the herbage for its species composition and fungal contamination. No obvious possible causative abnormalities were identified apart from a low total serum calcium level in one case. No fescue grass was found and no pathogenic fungi were detected.     

Urea as a measure of dilution of equine synovial fluid

This paper tests the hypothesis that serum and synovial urea concentrations are similar and that urea concentration can be used as an accurate marker for synovial fluid dilution in normal equine joints. Serum and synovial fluid urea concentrations were compared in 42 horses and were equivalent for individual horses (P<0.0001). Mean +/- s.e. serum concentration was 6.1+/-0.552 mmol/l and synovial concentration 6.0+/-0.459 mmol/l. The normal range for synovial urea concentration was determined as 2.5-7.7 mmol/l. The synovial urea concentration from different synovial structures in individual horses were compared and were equivalent (P = 0.002). Known dilutions of synovial fluid with saline were made. The actual and expected synovial urea concentrations were compared and were equivalent (P<0.001). An accurate method of calculating synovial fluid dilution has been determined.     

Bovine saccocystosis: patholgic features of naturally occurring infection with Sarcocystis cruzi.

Naturally occurring bovine sarcocystosis caused death and illness in eight dairy heifers. Clinical disease was characterized by cachexia, peripheral lymph node enlargement, and anemia. Increased amounts of serum enzymes and anti-Sarcocystis antibody titers were present in affected animal. Macroscopic findings in two heifers at necropsy included emaciation and serous atrophy. Necropsied heifers (No. 1 and 2) contained different developmental stages of Sarcocystis cruzi; each stage was characterized by specific histopathologic findings. Heifer 1 had vascular endothelial schizonts in various soft tissues, with mild mononuclear cell infiltration, alveolar capillary fibrinous thrombi, and multifocal splenic necrosis. Heifer 2 had developing young S cruzi cysts, in myofibrils of cardiac and skeletal muscles, with a concurrent multifocal degenerative myositis. Marked lymphoid hyperplasia occurred in both heifers.     

Rapid fluctuations in sea level recorded at huon peninsula during the penultimate deglaciation

About 140,000 years ago, the breakup of large continental ice sheets initiated the Last Interglacial period. Sea level rose and peaked around 135,000 years ago about 14 meters below present levels. A record of Last Interglacial sea levels between 116,000 years to 136, 000 years ago is preserved at reef VII of the uplifted coral terraces of Huon Peninsula in Papua New Guinea. However, corals from a cave situated about 90 meters below the crest of reef VII are 130, 000 +/- 2000 years old and appear to have grown in conditions that were 6 degreesC cooler than those at present. These observations imply a drop in sea level of 60 to 80 meters. After 130,000 years, sea level began rising again in response to the major insolation maximum at 126,000 to 128,000 years ago. The early (about 140,000 years ago) start of the penultimate deglaciation, well before the peak in insolation, is consistent with the Devils Hole chronology.     

Coral record of equatorial sea-surface temperatures during the penultimate deglaciation at huon peninsula

Uplifted coral terraces at Huon Peninsula, Papua New Guinea, preserve a record of sea level, sea-surface temperature, and salinity from the penultimate deglaciation. Remnants have been found of a shallow-water reef that formed during a pause, similar to the Younger Dryas, in the penultimate deglaciation at 130,000 +/- 2000 years ago, when sea level was 60 to 80 meters lower than it is today. Porites coral, which grew during this period, has oxygen isotopic values and strontium/calcium ratios that indicate that sea-surface temperatures were much cooler (22 degrees +/- 2 degreesC) than either Last Interglacial or present-day tropical temperatures (29 degrees +/- 1 degreesC). These observations provide further evidence for a major cooling of the equatorial western Pacific followed by an extremely rapid rise in sea level during the latter stages of Termination II.     

A method of assessing auditory and brainstem function in horses

Brainstem auditory evoked potential (BAEP) waveforms were recorded as a means of objectively evaluating auditory and brainstem function in horses. BAEP recordings were readily and repeatably recorded from horses, under minimal restraint, using signal averaging equipment. Clearly identified BAEP waveforms were obtained with compression clicks of 30-100 dB (HHL) at 10 Hz applied in the external auditory meatus of one ear and masking white noise (10 dB lower) in the other ear. Vertex positive (upwards) waveforms I through V were obtained with an active, subdermal electrode over the ipsilateral and contralateral zygomatic processes of the temporal bones and the reference electrode over the vertex. Recording sweep duration was 10 ms, amplifier sensitivity 10 microV/division, display gain x 10 and low and high amplifier filters set at 200 Hz to 2 kHz. Such recordings can be useful in evaluation of all clinical cases suspected of showing degrees of deafness, vestibular disease or brainstem disease, and in monitoring the progress of such cases.