Transferrin and iron contribute to the lipolytic effect of serum in isolated adipocytes

Previous reports have demonstrated that normal serum can increase the rate of adipocyte lipolysis in vitro. However, the nature of the lipolytic activity has remained obscure. We have investigated the lipolytic activity of human serum using isolated rat adipocytes. Human serum resulted in a dose-dependent stimulation of lipolysis (glycerol release) in adipocytes, with a half-maximal effective dose of 0.05% serum and with maximal stimulation with 1% serum. The effect of serum on glycerol release was rapid (within 30 min), and the effect was reversible. Partial purification of this lipolytic activity using gel filtration and ion-exchange chromatography demonstrates that a protein of approximately 80 kDa contributes to the lipolytic activity. Human transferrin mimicked the activity of partially purified serum, resulting in a maximal 50% increase in basal lipolysis. In addition, ferrous sulfate heptahydrate induced a biphasic increase in the rate of lipolysis, with a maximal increase of 50% at approximately 0.6 microg/ml iron. Inhibitors of protein kinase A (H89) and mitogen-activated protein kinase (PD98059) did not block the effect of serum on lipolysis, whereas the free radical scavenger N-acetyl-l-cysteine completely inhibited the effect. These findings suggest that the stimulatory effect of serum on lipolysis is in part mediated by iron, probably through a prooxidant mechanism.     

A novel solution for the notorious long-leg cylinder cast

Although the long-leg cylinder cast is an effective means of immobilization, it is prone to distal migration which commonly results in skin compromise. Described here is a simple technique that involves using adhesive tape as a suspension mechanism. This technique is clinically effective, has a low complication rate and requires only a small diversion from standard practice.     

Paraspinal nerve sheath tumors

Spinal tumors compose a vast heterogeneous group of neoplasms that are classified by origin into vertebral column, spinal canal, or paraspinal region tumors. Tumors with both intraspinal (intracanalicular) and paraspinal (extracanalicular) components that communicate via an intravertebral foramen are defined as "dumbbell tumors." This article focuses on the characteristics of a few types of paraspinal tumors, with special emphasis on the management of nerve sheath dumbbell tumors.     

Antipolymer antibodies in Danish women with silicone breast implants

OBJECTIVE: To use a new immunologic assay to evaluate antipolymer antibody (APA) levels among women with silicone breast implants (SBIs). METHODS: Women (n = 186) were identified through Danish population-based registers and categorized into six groups defined by prior breast surgery (silicone breast implantation/breast reduction/no breast surgery) and by the presence or absence of a prior hospital diagnosis of soft-tissue rheumatism (muscular rheumatism, ICD-8 codes 717.90 and 717.99). The women underwent blood tests, including an APA test, a clinical examination, and an interview focusing on rheumatic complaints. Blood samples were tested blindly. The severity of rheumatic symptoms/signs was scored from 1 (none) to 5 (severe) based on the clinical examination and interview. RESULTS: Women with SBIs did not have higher levels of APA than women without SBIs. The majority of women with SBIs had mild rheumatic complaints, and the severity of their symptoms was not related to APA levels. Among women who had previously been hospitalized because of soft-tissue rheumatism, there were more fibromyalgia cases, and their symptoms were more severe compared with those women without prior soft-tissue rheumatism; however, APA levels were not higher among these women. There was a significant difference in APA measurements resulting from between-kit variation (p less 0.01). CONCLUSIONS: Our data did not demonstrate higher APA levels among women with SBIs compared with controls. The large variation observed between the individual plates in the APA test should be evaluated in future studies.     

Latent Human Papillomavirus infection is comparable in the larynx and trachea

Recurrent respiratory papillomas are benign airway tumors caused by Human Papillomaviruses (HPVs) types 6 and 11. The disease is characterized by multiple recurrences of papillomas following surgical removal, caused by activation of latent HPV DNA. Most patients have laryngeal disease, while only a small subset has tracheal involvement. We have asked whether the lower frequency of tracheal papillomas was due to reduced prevalence of latent/subclinical tracheal HPV infection or reduced likelihood of activation to clinically apparent disease. A total of 121 biopsies of clinically normal laryngeal and tracheal tissues from 61 patients with laryngeal papillomas were analyzed for HPV DNA by polymerase chain reaction, confirmed by Southern blot hybridization. Patients were followed for 3-18 years (mean = 5.5 +/- 4.4), with only one developing subsequent tracheal disease. There was no significant difference in prevalence of latent HPV DNA between larynx and trachea, analyzing either those patients with a single biopsy or those with more than one biopsy of larynx, trachea, or both. There was also no significant difference between tracheal latency with HPV 6 and HPV 11. We conclude that HPV infects tracheal mucosa and is maintained as a latent infection in the trachea as efficiently as in the larynx. Therefore, we propose that the low frequency of tracheal disease reflects a lower frequency of HPV activation, and postulate that cellular factors that differ between the stratified squamous epithelium of the larynx and the ciliated pseudo-stratified columnar epithelium of the trachea contribute to this difference.     

Reduced penetrance of craniofacial anomalies as a function of deletion size and genetic background in a chromosome engineered partial mouse model for Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is a multiple congenital anomaly/mental retardation syndrome associated with del(17)(p11.2p11.2). The phenotype is variable even in patients with deletions of the same size. RAI1 has been recently suggested as a major gene for majority of the SMS phenotypes, but its role in the full spectrum of the phenotype remains unclear. Df(11)17/+ mice contain a heterozygous deletion in the mouse region syntenic to the SMS common deletion, and exhibit craniofacial abnormalities, seizures and marked obesity, partially reproducing the SMS phenotype. To further study the genetic basis for the phenotype, we constructed three lines of mice with smaller deletions [Df(11)17-1, Df(11)17-2 and Df(11)17-3] using retrovirus-mediated chromosome engineering to create nested deletions. Both craniofacial abnormalities and obesity have been observed, but the penetrance of the craniofacial phenotype was markedly reduced when compared with Df(11)17/+ mice. Overt seizures were not observed. Phenotypic variation has been observed in mice with the same deletion size in the same and in different genetic backgrounds, which may reflect the variation documented in the patients. These results indicate that the smaller deletions contain the gene(s), most likely Rai1, causing craniofacial abnormalities and obesity. However, genes or regulatory elements in the larger deletion, which are not located in the smaller deletions, as well as genes located elsewhere, also influence penetrance and expressivity of the phenotype. Our mouse models refined the genomic region important for a portion of the SMS phenotype and provided a basis for further molecular analysis of genes associated with SMS.     

The role of growth hormone in the pathogenesis of diabetic kidney disease

At present, diabetic kidney disease affects about 15-20% of all Type 1 diabetic patients and 20-40% of all patients with Type 2 diabetes. Preclinical research performed over the past decade has suggested growth hormone (GH) and insulin-like growth factors (IGFs) to be involved in the pathogenesis of diabetic kidney disease. Data obtained in knock-out (KO) mice with GH receptor (GHR)/GH binding protein (GHBP) gene-disruption have shown that these animals are protected against diabetes-induced renal changes. Further, diabetic mice treated with either a longacting somatostatin analogue or a specific GHR antagonist (GHRA) showed normalization of the diabetes-associated renal hypertrophy and glomerular enlargement and most importantly also a lowering effect on the diabetes-induced rise in urinary albumin excretion (UAE), a marker of renal damage. Based on these experimental data future studies are warranted to characterize the clinical potential of GH-inhibitors (e.g. GHRAs) as drugs for the treatment of diabetic renal complications.