Effects of L-dopa on expression of prolactin and synaptotagmin IV in 17-estradiol-induced prolactinomas of ovariectomized hemiparkinsonian rats

Parkinson's disease (PD) is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. Dopamine precursor L-dopa is used as the first-line treatment for PD. Evidence suggests neuroprotective effects of estrogens in PD. Since both E2 and L-dopa act as regulators of prolactin secretion from the pituitary gland, we investigated their effect on the expression of prolactin (PRL) in prolactinomas that developed in ovariectomized hemiparkinsonian rats treated with 17b-estradiol (E2). We also investigated the effect of E2 and L-dopa on the expression of synaptotagmin IV (Syt IV), an immediate early gene whose product is abundant in the pituitary gland and was found to be highly co-expressed with PRL in lactotrophs (> 90%). The hemiparkinsonian rat model was obtained by unilateral lesioning of dopaminergic nigrostriatal neurons. Rats received silastic tubing implants with E2 and were treated with L-dopa. ELISA and immunohistochemistry were used to assess the serum concentrations of PRL and E2 and expression of PRL and SytIV in the tissue of adenohypophysis, respectively. We found that high levels of serum 17b-estradiol were associated with the upregulation of Syt IV and PRL in PRL-ir cells, while treatment with L-dopa decreased the size of prolactinomas and downregulated Syt IV but had no effect on PRL expression or serum concentrations.

Common Challenges and Solutions Associated with the Preparation of Silicone-Injected Human Head and Neck Vessels for Anatomical Study

Neuroanatomy laboratory training is crucial for the education of neurosurgery residents and medical students. Since the brain is a complex and three-dimensional structure, it is challenging to understand the anatomical relationship of the cortex, internal structures, arteries, and veins without appropriate adjuncts. Several injection agents—including the inks/dyes, latex, polyester, acrylic resins, phenol, polyethylene glycol, and phenoxyethanol—have been explored. Colored silicon injection protocols for the head and neck vessels’ perfusion have greatly aided the study of neuroanatomy and surgical planning. This report presents a colored silicone injection method in detail, and also highlights the technical shortcomings of the standard techniques and workarounds for common challenges during 35 human cadaveric head injections. The human cadaveric head preparation and the coloring of the head vessels are divided into decapitation, tissue fixation with 10% formalin, the placement of the Silastic tubing into the parent vessels, the cleaning of the vessels from clots, and the injection of the colored silicone into the vessels. We describe the technical details of the preparation, injection, and preservation of cadaveric heads, and outline common challenges during colored silicone injection, which include the dislocation of the Silastic tubing during the injection, the injection of the wrong or inappropriate colored silicone into the vessel, intracranial vessel perforation, the incomplete silicone casting of the vessel, and silicone leakage from small vessels in the neck. Solutions to these common challenges are provided. Ethyl alcohol fixed, colored human heads provided the long-term preservation of tissue, and improve the sample consistency and preservation for the teaching of neuroanatomy and surgical technique.

Androgen sensitivity of prostate epithelium is enhanced by postnatal androgen receptor inactivation

Postnatal inactivation of epithelial androgen receptor (AR) in prostate epithelial AR knockout (PEARKO) mice results in hindered differentiation but enhanced proliferation of epithelial cells. As this resembles the precancerous proliferative atrophy of human prostates with undifferentiated but intensively replicating epithelial cells, we utilized the PEARKO mice to characterize the epithelial response to castration-induced involution with a focus on identifying the potential role of stromal AR and responsiveness of the androgen-deprived epithelia to the aromatizable androgen testosterone (T) or its nonaromatizable metabolite dihydrotestosterone (DHT). PEARKO and littermate control mice were orchidectomized at 8 wk of age and treated 2 wk later with subdermal implantation of 1-cm Silastic tubing filled with T or DHT for a week. Following castration, the prostatic involution and epithelial apoptosis did not significantly differ between control (intact AR) and PEARKO (only stromal AR) males, demonstrating that prostate epithelial involution following castration is mediated primarily via stromal AR-dependent apoptotic signals. Androgen replacement (T/DHT) for 7 days induced significant growth and epithelial proliferation in all prostate lobes in both control and PEARKO, but full regrowth was observed only in controls treated with T. In PEARKO, prostate androgen (T and DHT) treatment induced significant epithelial cell “shedding” into the lumen, with T treatment resulting in acinar disorganization, cyst formation, and aberrant epithelial structures, described as a “gland within a gland.” These data suggest that epithelial AR inactivation during postnatal prostate development sensitizes prostate epithelial cells to paracrine signaling mediated by stromal AR activity leading to indirectly androgen-induced epithelial hyperproliferation and formation of epithelial hyperplastic cysts by aromatizable androgens.

Characterization and Biocompatibility Studies of Layer-by-Layer Self-Assembled Humic Acid/Fe3+ Films

A semipermeable and non-inflammatory membrane is a prerequisite for the development of an implantable biosensor for continuous pain free monitoring of glucose levels in vivo. Humic acids (HAs) have been reported to have therapeutically relevant characteristics such as antiviral and anti-inflammatory.[1] This encouraged us to investigate the in vivo compatibility of HAs based multilayered films as a potential membrane material for implantable glucose sensors. Electrostatic layer-by-layer self-assembly technique of HAs with oppositely charged ferric ions was utilized to grow these films. Quartz Crystal Microbalance (QCM) and ellipsometric studies have shown repeatable, stepwise increase in mass and in film thickness during self-assembly. The growth of these assemblies exhibited strong dependence on pH and ionic strength of HAs solution and was correlated with the degree of ionization of carboxyl groups and the neutralization induced surface spreading. HAs films used in the biocompatibility study were very well tolerated by the tissue and no difference with silastic tubing, used as control, could be observed. All types of samples, including the controls, induced similar long-term tissue reaction showing almost no inflammation and a light to moderate fibrosis with some blood vessels present.

Parotid duct laceration repair in two horses : case report

Repair of parotid duct lacerations in 2 horses is described using intraluminal silastic tubing as a stent. The duct was lacerated traumatically at the facial vessel notch (incisura vasorum facialium) in the 1st horse, and iatrogenically after removal of an intraluminal sialolith after development of infection within the duct in the 2nd horse. In both cases, a silastic tube was passed retrograde into the duct via the salivary papilla, past the wound until the end lay rostroventral to the parotid salivary gland. The severed salivary ducts and the wounds were sutured. The external portion of the silastic tube was sutured to the skin and the tube left in place. Recovery in the 1st case was uneventful. In the 2nd case a salivary duct/cutaneous fistula formed at a wound distant from the sutured wound, which healed spontaneously. This technique differs from a similar described technique in that the stent tube exits the oral cavity and is attached to the outer skin surface.