The role of endoscopy in bovine internal medicine - A review of current indication fields

Endoscopy in bovine internal medicine has come a long way from the first profound research papers in the 1980s to its present-day use. This paper reviews the progress in the 2000s and identifies the main application fields for diagnostic and therapeutic use. Inclusion criteria for scientific papers and reports encompassed focus on endoscopic examination techniques in cattle in the field of internal medicine and publication in a peer reviewed journal (case report/review/original research paper/short communication). Only papers written in English or German language were considered. Studies on laparoscopy, theloscopy, and bronchoscopy show that endoscopic approaches often enable more rapid and accurate diagnosis and treatment options for single diseased animals as well as on a herd level. Oesophagoscopy, rumenoscopy, cystoscopy and thoracoscopy have also been increasingly studied and proven to be safe and effective tools with some limitations in diagnosing and/or treating various diseases in cattle. Scientific approaches explored the epidural space in cattle and comparison of different endoscope systems lead to recommendations for sinuscopy. Yet, this narrative literature review clearly shows that unlike in human medicine, where endoscopy as a minimally invasive technique is used for countless routine procedures every day, there is still some catching up to do in bovine medicine even though the potential of endoscopy in this field has been documented.

Llamas and alpacas in Europe: Endoparasites of the digestive tract and their pharmacotherapeutic control

There are distinctive specifications for veterinary medical care of South American camelids (SACs), namely, llamas, alpacas, vicunas and guanacos. Camelids are classified as food-producing animals, but as veterinary medicinal products are often only licensed for domestic food-producing species such as horses, goats, sheep and cattle, treatment of SACs generally requires off-label use of drugs. Endoparasitism is a major health concern in camelids and can result in severe clinical diseases and economic losses. There is still a lack of work on the pharmacokinetics, safety and efficacy for most antiparasitic drugs used in SACs. Even when choosing an appropriate route of administration, several aspects must be considered such as the fact that pour-on formulations are largely ineffective in camelids due to the unique features of llama and alpaca skin and hair that result in extremely low drug bioavailability. This review focuses on the main endoparasites of the digestive tract in llamas and alpacas in Europe and pharmacotherapeutic options based on current knowledge.

Use of endoscopy for examination of the sacral epidural space in standing cattle

OBJECTIVE

To develop an epiduroscopic technique for use in standing cattle and describe the endoscopically visible anatomic structures of the epidural space in the sacrococcygeal area.

ANIMALS

6 healthy nonlactating, nonpregnant cows (mean +/- SD age, 60 +/- 18.5 months; mean weight, 599.7 +/- 63.87 kg) and 3 bovine cadavers.

PROCEDURES

Cadavers were used to allow familiarization with the equipment and refinement of the technique. Following these experiences, procedures were performed in live animals. Each cow was restrained in a stock. After sedation with xylazine (0.03 mg/kg, IV), 2% lidocaine hydrochloride (0.25 mg/kg) was injected epidurally in the first intercoccygeal or the sacrococcygeal intervertebral space. By use of an introducer set (guidewire and dilation trocar and shaft), a flexible endoscope (length, 75 cm; diameter, 2.3 mm) was inserted through the dilation shaft into the epidural space. To obtain an optimal view, small amounts of air were insufflated into the epidural space through the working channel of the endoscope via a syringe with special filter.

RESULTS

Anatomic structures of the epidural space that were viewed by means of the endoscopic procedure included blood vessels, connective tissue, fat, nerves, and the spinal dura mater. No adverse events were detected during epiduroscopy, and it was tolerated well by all 6 cows.

CONCLUSIONS AND CLINICAL RELEVANCE

In ruminants, epidural structures can be viewed via endoscopy. Such epiduroscopic procedures may be useful in anatomic studies as well as for the diagnosis of disease or therapeutic interventions in ruminants.

Hypoxia-induced gene expression occurs solely through the action of hypoxia-inducible factor 1alpha (HIF-1alpha): role of cytoplasmic trapping of HIF-2alpha

The hypoxia-inducible factors 1alpha (HIF-1alpha) and 2alpha (HIF-2alpha) have extensive structural homology and have been identified as key transcription factors responsible for gene expression in response to hypoxia. They play critical roles not only in normal development, but also in tumor progression. Here we report on the differential regulation of protein expression and transcriptional activity of HIF-1alpha and -2alpha by hypoxia in immortalized mouse embryo fibroblasts (MEFs). We show that oxygen-dependent protein degradation is restricted to HIF-1alpha, as HIF-2alpha protein is detected in MEFs regardless of oxygenation and is localized primarily to the cytoplasm. Endogenous HIF-2alpha remained transcriptionally inactive under hypoxic conditions; however, ectopically overexpressed HIF-2alpha translocated into the nucleus and could stimulate expression of hypoxia-inducible genes. We show that the factor inhibiting HIF-1 can selectively inhibit the transcriptional activity of HIF-1alpha but has no effect on HIF-2alpha-mediated transcription in MEFs. We propose that HIF-2alpha is not a redundant transcription factor of HIF-1alpha for hypoxia-induced gene expression and show evidence that there is a cell type-specific modulator(s) that enables selective activation of HIF-1alpha but not HIF-2alpha in response to low-oxygen stress.

Requirement for p38alpha in erythropoietin expression: a role for stress kinases in erythropoiesis

Activity of the p38alpha MAP kinase is stimulated by various stresses and hematopoietic growth factors. A role for p38alpha in mouse development and physiology was investigated by targeted disruption of the p38alpha locus. Whereas some p38alpha(-/-) embryos die between embryonic days 11.5 and 12.5, those that develop past this stage have normal morphology but are anemic owing to failed definitive erythropoiesis, caused by diminished erythropoietin (Epo) gene expression. As p38alpha-deficient hematopoietic stem cells reconstitute lethally irradiated hosts, p38alpha function is not required downstream of Epo receptor. Inhibition of p38 activity also interferes with stabilization of Epo mRNA in human hepatoma cells undergoing hypoxic stress. The p38alpha MAP kinase plays a critical role linking developmental and stress-induced erythropoiesis through regulation of Epo expression.