Constitutively Elevated Blood Serotonin Is Associated with Bone Loss and Type 2 Diabetes in Rats

Reduced peripheral serotonin (5HT) in mice lacking tryptophan hydroxylase (TPH1), the rate limiting enzyme for 5HT synthesis, was reported to be anabolic to the skeleton. However, in other studies TPH1 deletion either had no bone effect or an age dependent inhibition of osteoclastic bone resorption. The role of 5HT in bone therefore remains poorly understood. To address this issue, we used selective breeding to create rat sublines with constitutively high (high-5HT) and low (low-5HT) platelet 5HT level (PSL) and platelet 5HT uptake (PSU). High-5HT rats had decreased bone volume due to increased bone turnover characterized by increased bone formation and mineral apposition rate, increased osteoclast number and serum C-telopeptide level. Daily oral administration of the TPH1 inhibitor (LX1032) for 6 weeks reduced PSL and increased the trabecular bone volume and trabecular number of the spine and femur in high-5HT rats. High-5HT animals also developed a type 2 diabetes (T2D) phenotype with increased: plasma insulin, glucose, hemoglobin A1c, body weight, visceral fat, β-cell pancreatic islets size, serum cholesterol, and decreased muscle strength. Serum calcium accretion mediated by parathyroid hormone slightly increased, whereas treatment with 1,25(OH)₂D₃ decreased PSL. Insulin reduction was paralleled by a drop in PSL in high-5HT rats. In vitro, insulin and 5HT synergistically up-regulated osteoblast differentiation isolated from high-5HT rats, whereas TPH1 inhibition decreased the number of bone marrow-derived osteoclasts. These results suggest that constitutively elevated PSL is associated with bone loss and T2D via a homeostatic interplay between the peripheral 5HT, bone and insulin.     

Metabolism of Nicotinamide Adenine Dinucleotide in Human and Bovine Strains of Mycobacterium tuberculosis

A marked difference was found to exist between the nicotinamide adenine dinucleotide (NAD) glycohydrolase activity of human strains of Mycobacterium tuberculosis as compared with bovine strains. Human strains had from 6- to 20-fold higher NAD glycohydrolase activity than bovine strains. This finding explains the accumulation of free nicotinic acid in the culture medium by human strains and not by bovine strains. The biosynthetic intermediates nicotinic acid mononucleotide and deamido-NAD were not degraded by either human or bovine strains of M. tuberculosis; hence these nucleotides do not represent a source of the nicotinic acid accumulated by the human strains.     

Membranes of EBV-carrying virus nonproducer cells inhibit leukocyte migration of EBV-seropositive but not seronegative donors

We have previously shown that the leukocytes of healthy EBV-seropositive (but not seronegative) donors respond with migration inhibition (LMI) when confronted with extracts of EBV-carrying (but not EBV negative) cells. In the present study, we have examined whether this EBV-specific LMI response is capable of detecting a membrane antigen on the surface of EBV-carrying virus nonproducer cells. Crude membranes from EBV-genome carrying and EBV-negative cell lines were used as antigen. Contamination with the EBV-determined nuclear antigen (EBNA) was ruled out. Membranes from EBV-genome carrying nonproducer cells inhibited the migration of leukocytes from healthy seropositive donors, whereas membranes from EBV-negative lines had no such effect. Seronegative donors did not show any LMI. The clear difference between the EBV-negative Ramos line and its EBV-converted sublines was particularly conclusive in showing that the membrane component is determined or induced by the viral genome.     

Alpha-lipoic acid affects the oxidative stress in various brain structures in mice with methionine and choline deficiency

Deficiency in methionine or choline can induce oxidative stress in various organs such as liver, kidney, heart, and brain. This study was to examine the effects of alpha-lipoic acid (LA) on oxidative stress induced by methionine and choline deficiency (MCD) in several brain structures. Male mice C57BL/6 (n = 28) were divided into four groups: (1) control – continuously fed with standard chow; (2) LA – fed with standard chow and receiving LA; (3) MCD2 – fed with MCD diet for two weeks, and (4) MCD2+LA – fed with MCD diet for two weeks and receiving LA (100 mg/kg/day intraperitonealy [i.p.]). Brain tissue (cortex, hypothalamus, striatum and hippocampus) was taken for determination of oxidative stress parameters. MCD diet induced a significant increase in malondialdehyde and NOx concentration in all brain regions, while LA restored their content to normal values. Similar to this, in MCD2 group, activity of total SOD, MnSOD, and Cu/ZnSOD was reduced by MCD diet, while LA treatment improved their activities in all brain structures. Besides, in MCD2 group a decrease in catalase activity in cortex and GSH content in hypothalamus was evident, while LA treatment induced an increase in catalase activity in cortex and striatum and GSH content in hypothalamus. LA treatment can significantly reduce lipid peroxidation and nitrosative stress, caused by MCD diet, in all brain regions by restoring antioxidant enzymes activities, predominantly total SOD, MnSOD, and Cu/ZnSOD, and to a lesser extent by modulating catalase activity and GSH content. LA supplementation may be used in order to prevent brain oxidative injury induced by methionine and choline deficiency.     

Prevalence of chlamydial genital infection and associated risk factors in adolescent females at an urban reproductive health care center in Croatia

The study was undertaken to determine the prevalence of chlamydial genital infection in sexually active, urban adolescent females 15-19 years; to identify behavioral, demographic, and clinical factors associated with chlamydial infections; and to develop criteria for potential screening strategies. 500 adolescent women, median age 17.7 years, who visited gynecological outpatient clinic in Children's Hospital Zagreb for different reasons were enrolled in this study. Gynecological exam, colposcopy, detection of chlamydial infection by the rapid direct immunoassay of endocervical swab (Clearview Chlamydia-Unipath), endocervical cytological examination--Papanicolaou smear, and questionnaire to obtain demographic, social, behavioral and presence of symptoms data were performed. Positive Chlamydia trachomatis test were found in 16.4% of participants, cytologic cervical abnormalities--cervical intraepithelial neoplasia (CIN I-CIN III) were found in 25.2% and cytological signs of Human papilloma virus were found in 11.4%. Stepwise multivariate logistic regression analysis identified five factors associated with infection: the age of menarche < or =13 years, > or =4 lifetime sexual partners, non-use of contraception (rare or never), cervical friability, and abnormal Papanicolaou test. Urban adolescent sexually active women are at high risk for chlamydial infection and other sexually transmitted diseases including HIV infection. Association between chlamydial genital infection and risk-taking sexual and contraceptive behavior was found. Routine Chlamydia trachomatis testing for this population is recommended as well as implementation of school based sexual health education because of their risk-taking sexual behavior.     

RETRACTED ARTICLE: Age-dependent Increase in Desmosterol Restores DRM Formation and Membrane-related Functions in Cholesterol-free DHCR24−/− Mice

Cholesterol is a prominent modulator of the integrity and functional activity of physiological membranes and the most abundant sterol in the mammalian brain. DHCR24-knock-out mice lack cholesterol and accumulate desmosterol with age. Here we demonstrate that brain cholesterol deficiency in 3-week-old DHCR24^−/− mice was associated with altered membrane composition including disrupted detergent-resistant membrane domain (DRM) structure. Furthermore, membrane-related functions differed extensively in the brains of these mice, resulting in lower plasmin activity, decreased β-secretase activity and diminished Aβ generation. Age-dependent accumulation and integration of desmosterol in brain membranes of 16-week-old DHCR24^−/− mice led to the formation of desmosterol-containing DRMs and rescued the observed membrane-related functional deficits. Our data provide evidence that an alternate sterol, desmosterol, can facilitate processes that are normally cholesterol-dependent including formation of DRMs from mouse brain extracts, membrane receptor ligand binding and activation, and regulation of membrane protein proteolytic activity. These data indicate that desmosterol can replace cholesterol in membrane-related functions in the DHCR24^−/− mouse. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. An erratum to this article can be found at     

Laryngeal inflammatory myofibroblastic tumor in a man: a case report

Inflammatory myofibroblastic tumor (IMT) is a pseudosarcomatous lesion occurring in soft tissue and organs. It is known under a wide number of terms, such as inflammatory pseudotumor, plasma cell granuloma, pseudosarcomatous myofibroblastic proliferation. IMT is most commonly located in the lung, while laryngeal location is rarely described. Due to its biology it can be misdiagnosed as a malignant tumor. We present a case of IMT of larynx, recognized in time and treated with laser ablation. Our case demonstrates the importance of timely IMT recognition in order to avoid overtreatment. This diagnosis should also alert clinicians to close follow-up of these patients.     

Acute skin sun damage in children and its consequences in adults

Children spend more time outdoors than adults and there is compelling evidence that childhood is a particularly vulnerable time for the photocarcinogenic effects of the sun. The negative effects of solar radiation are accumulated during the entire lifetime; however 80% of total lifetime sun exposure is taking place before the age of 18 years. Child skin is more sensitive than adult skin because natural defense mechanisms are not fully developed. A short exposure to midday sun will result in sunburns. Epidemiologic studies show a higher incidence of malignant melanoma in persons with a history of sunburns during childhood and adolescence. Sun exposure among infants and pre-school children is largely dependent on the discretion of adult care providers. Sun protective habits of mothers may predict the level of sun exposure in children. It is very important to transfer the knowledge and positive habits of proper sun protection to children. The purpose of sun-safety behavior is not to avoid outdoor activities, but rather to protect the skin from detrimental sun effects. Proper sun protection of children includes protection from excessive sun exposure, sunburns and other forms of skin damage caused by sun, which may lead to the future development of skin cancers. This paper reviews acute skin reactivity to sun in childhood and adolescence that causes damage in skin structure and function and produces undesirable chronic changes in adults.     

"Halo nevi" and UV radiation

Halo nevi, also termed Sutton nevi, are defined as benign melanocytic nevi that are surrounded by an area of depigmentation resembling a halo. Halo nevi are common in children and young adults, with a mean age at onset of 15 years. The incidence in the population is estimated to be approximately 1%. Affected individuals frequently have multiple lesions which are usually localized on the back. A familial tendency for halo nevi has been reported. The etiology of halo nevi is unknown. It is an autoimmune response and T lymphocytes are considered to play a key role in the progressive destruction of nevus cells. Halo nevi may be associated with autoimmune disorders such as vitiligo, Hashimoto thyroiditis, alopecia areata, celiac disease, atopic dermatitis and others. It has been proved that halo nevi are detected after an intense sun exposure especially after sunburns. The etiology of halo nevi, association with malignant melanoma and the role of sun exposure in the development of halo nevi are discussed.     

Purification of the Epstein-Barr virus-determined nuclear antigen from Epstein-Barr virus-transformed human lymphoid cell lines.

The Epstein-Barr virus-determined nuclear antigen (EBNA) was purified from extracts of the human lymphoid cell lines Raji, Namalwa, and B95-8/MLD by two different methods. In the first approach, the apparently native antigen was purified 1,200-fold by a four-step procedure involving DNA-cellulose chromatography, blue dexptran-agarose chromatography, hydroxyapatite chromatography, and gel filtration, employing complement fixation as the assay procedure. Such EBNA preparations specifically inhibited the anticomplement immunofluorescence test for EBNA and bound to methanol/acetic acid-fixed metaphase chromosomes. The purified antigen, which has a molecular weight of 170,000 to 200,000, yielded a single protein band of molecular weight about 48,000 by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. These data indicate that native EBNA has a tetrameric structure. In the second purification method, EBNA-containing cell extracts containing radioactively labeled proteins were incubated with anti-EBNA-positive sera, and antigen-antibody complexes were adsorbed to matrix-bound staphylococcal protein A. The bound proteins were then released with an SDS-containing buffer, and denatured EBNA was separated from antibody chains by SDS-polyacrylamide gel electrophoresis and visualized by fluorography. The denatured EBNA obtained in radiochemically pure form by this procedure has a molecular weight of about 48,000, so both methods yield an EBNA monomer of the same size.