July 17, 2001 98 9306 -9311 Abstract Myostatin is a transforming growth factor-β family member that acts as a negative regulator of skeletal muscle mass. To identify possible myostatin inhibitors that may have applications for promoting muscle growth, we investigated the regulation of myostatin signaling. The purified C-terminal myostatin dimer was capable of binding the activin type II receptors, Act RIIB and, to a lesser extent, Act RIIA. Binding of myostatin to Act RIIB could be inhibited by the activin-binding protein follistatin and, at higher concentrations, by the myostatin propeptide. Independent transgenic mouse lines for each construct exhibited dramatic increases in muscle mass comparable to those seen in myostatin knockout mice.

Review Article The underappreciated role of muscle in health and disease1⫺3 ABSTRACT Muscle plays a central role in whole-body protein metabolism by serving as the principal reservoir for amino acids to maintain protein synthesis in vital tissues and organs in the absence of amino acid absorption from the gut and by providing hepatic gluconeogenic precursors. Whereas the precise in vivo energetics of muscle protein turnover are uncertain, a conservative estimate can be made on the basis of muscle protein synthesis. If there is a preexisting deficiency of muscle mass before trauma, the acute loss of muscle mass and function may push an individual over a threshold that makes recovery of normal function unlikely to ever occur. Protein intake above the currently recommended EAR of 0.66 mg kgҀ1 dҀ1 stimulates the FSR of muscle protein, and muscle FSR has been shown to be positively correlated with strength.

A study of 1004 patients with gastrointestinal smooth-muscle tumours has found that tumour location, size, mitotic index (MI) and patient age each carry independent prognostic value. There was a significant difference in site-specific survival, with 10-year survival varying between 50% and 70%. MI was found to be highly site-dependent, and the significance of the index was particularly stark when comparing survival curves for stomach and small bowel tumours. While the study found that tumour location, size, MI and age are useful in predicting patient prognosis, better methods are still needed to accurately predict clinical course.

In addition to the granular cell tumors there have been described some tumors which seem to partake of the characteristics of both smooth and striated muscle cells and others in which it seems impossible to decide whether they are smooth or striated muscle cell tumors. Most of the granular celt tumors and the heart rhabdomyomas are benign, while all of the other striated muscle cell tumors are either definitely or potentially malignant. Since Case 78 had two apparently independent tumors in the thigh and axilla and Case ioo tumors in both arms, the distribution of I23 tumors from the I2I cases will be recorded. In four months he was dead. 462 Volume 123 RHABDOMYOSARCOMA OF MUSCLES Number 8 Microscopic: The tumor is made up of masses of large cells of extremely varied shape, including occasional strap forms with nuclei in tandem, and more giant cells with several nuclei near the center of the cell and vacuoles in the cytoplasm.

Tumors of especially rapid growth, and young, wellgrown fowls of the variety in which the tumor originally occurred, namely, the barred Plymouth Rock, were used throughout. TUMORS RESULTING FROM A FILTRATE. The tumors which result from the injection of a cell-free filtrate take much longer to appear. 401 of a bit of tumor tissue one millimeter in diameter may give rise in the course of a week to a growing nodule I. 5 centimeters broad; whereas, following the injection of a filtrate, not the slightest trace of tumor is palpable for from ten days to three weeks. P a r t of a tumor in the left breast, resulting from the injection of the filtrate of experiment IV. T h e muscle fibres are largely invaded and replaced by tumor cells.

There occur tumors composed of capillary blood vessels with one or more layers of rounded cells arranged about them, which cannot be called glomus tumors because they lack the organoid features of those encapsulated complex neoplasms, yet differ from simple capillary hemangiomata because of the presence of their perivascular cells. Where recent growth has occurred, the capillaries are simple enldothelial tubes supported by reticulin fibers, but where the tumor is older, the endothelia are surrounded by thick compacted collagen sheaths of a hyaline aspect in ordinary stains and the tumor cells are outside of these. The vascular aspect of the tumor is clearly shown in the liver metastasis, which is composed of many endothelial tubes surrounded by rounded cells so closely placed that the tumor cells of one unit often touch those of its neighbors. One should be very certain that the growth is basically vascular and not a tumor whose cells are nourished by a rich vascular network such as one sees in many tumors of endocrine organs, in some Ewing tumors of bone marrow, and elsewhere.

C. Microscopic Organization Before I discuss the organization of vessels in the tumor microcirculation, it is worthwhile to review the most commonly accepted terminology of blood vessels in an "Ideal" normal II. Vascular Morphology of Tumors: Structure, Organization, and Volume of Tumor Vascular Compartment The literature on the vascular morphology of human and animal tumors has been reviewed recently by Warren and Shubik. A. Methods The methodologies used to obtain tumor vascular parameters have included: standard histological examination of tumors using light or electron microscopy; examination of tumor tissue injected with agents which are retained by blood vessels; examination of the cast of the tumor vasculature made using a polymer or other substances; gross or microscopic radiography and angioradiography with or without the use of vasoactive agents; and intravital observation of tumor microcirculation with or without contrast agents. Some studies show that the fractional vascular volume of tumors remains fairly constant during growth, suggesting an increase in the number of blood vessels with low blood flow, while others show that the fractional vascular volume decreases as a tumor grows, in agreement with the observation that tumor blood flow rate per unit tumor weight decreases as a tumor grows. E Measured in superficial layer of tumor weighing 1-17 g. Mean interstitial fluid pressure in the center of tumor -16 mm Hg. " 30'C. which are numerically dominant in a tumor, and increased interstitial fluid pressure may reduce extravasation of fluid and solute molecules in tumors; and cause flow stasis and hypoxia in tumors.

The article discusses the history and evolution of the concept of painful subcutaneous tubercle, which is characterized by severe paroxysmal pain. The article notes that while neuromyoarterial glomus was initially thought to be the sole cause of this condition, there are other lesions that may also be labeled as painful subcutaneous tubercles. The author goes on to trace the history of cases of leiomyomas, which are now recognized as a form of painful subcutaneous tubercles. The article highlights the growing interest in these tumors, particularly in the United States, and underscores the need for further research into their diagnosis and treatment. Overall, the article provides a comprehensive overview of the history and evolution of the study of painful subcutaneous tubercles and their various forms.

The text discusses the hyperplasia of adjacent bone in endotheliomas, a type of meningeal tumor. It highlights the lack of understanding among medical professionals about the relationship between the tumor and bone hyperostosis. The author argues against the belief that the bone growth causes the tumor and presents data from their clinic to support their view. The article challenges the established understanding of endotheliomas and raises the need for further research. The text provides insightful information about a specific aspect of a medical condition and emphasizes the importance of continued examination and discussion among medical professionals.

In skeletal muscle, both systems are under FoxO regulation and their excessive activation induces severe muscle loss. Efficient inhibition of autophagy in skeletal muscles was confirmed by suppression of LC3 lipidation and accumulation of p62 and LC3 proteins in extracts of adult fast and slow muscles. We used two models of muscle atrophy, fasting and denervation, and we compared Atg7 null muscles with controls. Denervation Aggravates Morphological Abnormalities and Muscle Loss in Atg7−/− Muscles Quantification of muscle loss after 2 weeks from denervation.