Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations.

Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs) and parthenogenic ESCs (pESCs) are derived from the embryo proper while embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and germ-line stem cells (GSC) are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs) isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs), have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential.

Management of gestational gigantomastia.

BACKGROUND: Gigantomastia of pregnancy is a rare, severely debilitating condition characterized by massive enlargement of breasts and resulting in tissue necrosis, ulceration, infection, and, occasionally, hemorrhage. Typically, resolution of breast hypertrophy to near prepregnancy size occurs in the postpartum period. Treatment is controversial. METHODS: The authors present a patient with gestational gigantomastia for whom nonoperative management failed and who subsequently required bilateral mastectomies. In addition, the authors performed a comprehensive review of reported cases and generated a treatment algorithm. RESULTS: The patient tolerated the mastectomies well and went on to deliver a healthy child. Postpartum delayed breast reconstruction with tissue expansion and implant placement yielded good results. The literature review demonstrates that medical management has successfully avoided surgery during gestation in 39 percent of cases since 1968. However, 35 percent of patients eventually underwent breast reduction (12 percent) or mastectomy (88 percent) during pregnancy. Spontaneous or elective termination of the pregnancy accounted for 30 percent of outcomes. Patients who underwent breast reduction and then became pregnant had a 100 percent (four of four patients) chance of recurrence. Two women had mastectomy and subsequent pregnancies. One woman developed multiple small areas of recurrence that were surgically excised. The other woman had two additional pregnancies with no recurrence of symptoms. CONCLUSIONS: Medical therapies to manage gestational gigantomastia are inconsistent in outcome. Since some patients respond, these therapies are worth trying. However, if the patient and/or fetus are experiencing significant morbidity, then surgical intervention is warranted. Breast reduction or mastectomy with delayed reconstruction is the preferred procedure. If the mother is considering future pregnancies, mastectomy offers the lowest risk of recurrence.

A sequential double labeling technique for studying changes in motoneuronal projections to muscle following nerve injury and reinnervation.

The purpose of this study was to develop an anatomical technique that could directly demonstrate the motoneuron projections to the muscle both before injury and again following reinnervation. Investigation focused on the identification of a long-term retrograde fluorescent tracer that would label original motoneurons and persist long enough for reinnervating motoneurons to become labeled by a second fluorescent tracer. True Blue (TB) was evaluated as a potential long-term tracer, Fluoro-ruby (FR) and Fluoro-emerald (FE) were tested as potential short-term tracers in 45 adult Sprague-Dawley rats. In the initial phase of the study, TB was injected into the tibialis anterior (TA) muscle in 16 rats and sacrificed 1 week to 6 months later, to study its persistence. During the second stage, a short-term tracer was injected into the TA muscles bilaterally in 15 rats with survival time ranging from 4 to 28 days. Sequential double labeling was subsequently performed using the combination of TB and FR in 14 rats. The number and brightness of TB cells did not change over 6 months time, a period sufficient for complete reinnervation. FR and FE showed maximum labeling of motoneurons at 1 week after tracer application. In the double labeling study, we could easily distinguish double-labeled cells from those labeled only by TB or FR. These results suggest that sequential double labeling of TB and FR is a valuable method for long-term muscle reinnervation studies.