Armando Rosales

Retina-derived microglial cells induce photoreceptor cell death in vitro

In animals with retinal degeneration, the presence of activated microglial cells in the outer retina during the early stages of injury suggests that they may be involved in the ensuing photoreceptor cell death. In the following study, we investigated the effects of rat retina-derived microglial cells on a photoreceptor cell line (661w) using cell culture techniques. The difficulty of obtaining pure populations of photoreceptor cells necessitated our use of the 661w photoreceptor cells generated from retinas of transgenic mice. 661w Cells were incubated for 24-48 h in basal medium or basal medium conditioned by activated microglial cells (MGCM) or Müller cells (MCCM), and tested for cell death using lactate dehydrogenase (LDH) assay. The induction of apoptosis in the 661w cells by MGCM was investigated using Terminal deoxynucleotidyl Transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) and DNA laddering. Treatment of 661w cells with MGCM for 48 h resulted in approximately 73% of cells dead as compared with 19-20% of cells grown in either basal medium or MCCM. Serum supplementation or pretreatment with heat did not abolish the cytotoxicity of MGCM. More TUNEL-positive cells were observed in MGCM-treated cultures as compared with those in basal medium. Bands in multiples of approximately 180 bp formed DNA ladders in MGCM-treated but not in basal medium-treated samples. Our study shows that microglial cells release soluble product(s) that induce degeneration of cultured photoreceptor cells. Moreover, the mechanism of microglia-induced photoreceptor cell death may involve apoptosis similar to that observed in animals with retinal degeneration.

3D‐model of adult cardiac stem cells promotes cardiac differentiation and resistance to oxidative stress

The regenerative inadequacy of the injured myocardium leads to adverse remodeling, cardiac dysfunction, and heart disease. Stem cell‐replacement of damaged myocardium faces major challenges such as inappropriate differentiation, cellular uncoupling, scar formation, and accelerated apoptosis of transplanted cells. These challenges can be met by engineering an in vitro system for delivering stem cells capable of cardiac differentiation, tissue integration, and resistance to oxidative stress. In this study, we describe the formation of three‐dimensional (3D) cell aggregates (“cardiospheres”) by putative stem cells isolated from adult dog myocardium using poly‐L‐ornithine. De novo formation of cardiospheres in growth factor‐containing medium occurred over a period of 2–3 weeks, but accelerated to 2–3 days when seeded on poly‐L‐ornithine. Older cardiospheres developed foci of “beating” cells upon co‐culture with rat neonatal cardiomyocytes. Cardiospheres contained cells that exhibited characteristics of undifferentiated cells; differentiating cardiomyocytes with organized contractile machinery; and vascular cells capable of forming “vessel‐like” networks. They exhibited strong resistance to elevated concentrations of hydrogen peroxide in culture and survived subcutaneous injections without undergoing neoplastic transformation up to 3 weeks post‐transplantation. These findings suggest that cardiospheres are potentially useful for delivering functional stem cells to the damaged heart. J. Cell. Biochem. 105: 612–623, 2008.

Bilateral symmetrical supernumerary heads of biceps brachii with rare pectoralis major insertion

AbstractDuring a routine dissection of a 51-year-old Caucasian male cadaver, bilateral symmetrical supernumerary heads (SH) of the biceps brachii muscles with insertion into the pectoralis major (PM) muscles were discovered. Multiple case reports have documented supernumerary heads for the biceps brachii; however, none have shown bilateral insertion into the pectoralis major. This study describes a previously undocumented variation of the SH that has potential for clinical impact. Healthcare providers could be confounded by patients presenting with shoulder pain or muscle tears as a result of the anomaly. Furthermore, MRI studies on patients with possible shoulder muscle tears could reveal unexpected results. Such cases would warrant consideration of SH anomaly and treatment should be adjusted accordingly. The significant bulk and angle of the SH insertion on the PM we observed changes force vectors which would have an unknown effect in performance, surgical interventions and pain syndromes. A second biceps brachii anomaly was observed on the left brachium in addition to the bilateral SH. We postulate that these variants provide the potential for clinical complications regarding muscular injury to these aforementioned muscle groups.

A Cadaveric Study on the Surface Projection of the Dorsal Scapular Nerve

Background: Dorsal scapular nerve (DSN) syndrome is often associated by dull or aching pain along the medial border of the scapula that can radiate to the lateral aspect of the upper limb. The primary cause of this syndrome is due to the impingement or entrapment of this nerve at the middle scalene muscle. The purpose of this study is to identify the surface projection of the DSN relative to the middle scalene muscle by using the transverse plane of the laryngeal prominence and the posterior border of the sternocleidomastoid (SCM) muscle as reference points along with approximating the nerves location using thumb interphalangeal joint (IPJ) width. Methods: The surface location of the DSN was examined in 10 embalmed adult cadavers. The posterior border of the SCM muscle was palpated and outlined along with the transverse plane of the laryngeal prominence. A resin dye was injected at a distance of 2.08 cm (~ 1 thumb IPJ width) medial to the intersection of the posterior border of the SCM and the transverse plane of the laryngeal prominence. Dissections were performed to reveal and record the location of the dye. The distance between the location of the dye to the DSN was also measured. Results: The overall accuracy of the injection study revealed that the scalene muscles were consistently located. Specifically, 50% of the injections were found at the middle scalene muscle, 20% was between the anterior and middle scalene muscles, 10% at the anterior scalene muscle, 10% between the middle and posterior scalene muscles, and 10% was located at the posterior scalene muscle. Conclusion: This investigation will provide clinicians a useful and convenient method to determine the surface projection of the DSN at its entrapment site for the purpose of diagnosis and therapeutic treatment.