Mice deficient in interleukin-1 converting enzyme are resistant to neonatal hypoxic-ischemic brain damage

Interleukin-1 (IL-1) converting enzyme (ICE) is a cysteine protease that cleaves inactive pro-IL-1beta to active IL-1beta. The pro-inflammatory cytokine IL-1beta is implicated as a mediator of hypoxic-ischemic (HI) brain injury, both in experimental models and in humans. ICE is a member of a family of ICE-like proteases (caspases) that mediate apoptotic cell death in diverse tissues. The authors hypothesized that in neonatal mice with a homozygous deletion of ICE (ICE-KO) the severity of brain injury elicited by a focal cerebral HI insult would be reduced, relative to wild-type mice. Paired litters of 9- to 10-day-old ICE-KO and wild-type mice underwent right carotid ligation, followed by 70 or 120 minutes of exposure to 10% O2. In this neonatal model of transient focal cerebral ischemia followed by reperfusion, the duration of hypoxia exposure determines the duration of cerebral ischemia and the severity of tissue damage. Outcome was evaluated 5 or 21 days after lesioning; severity of injury was quantified by morphometric estimation of bilateral cortical, striatal, and dorsal hippocampal volumes. In animals that underwent the moderate HI insult (70-minute hypoxia), damage was attenuated in ICE-KO mice, when evaluated at 5 or 21 days post-lesioning. In contrast, in mice that underwent the more severe HI insult (120-minute hypoxia), injury severity was the same in both groups. Reductions in intra-HI CBF, measured by laser Doppler flow-metry, and intra- and post-HI temperatures did not differ between groups. These results show that ICE activity contributes to the progression of neonatal HI brain injury in this model. Whether these deleterious effects are mediated by pro-inflammatory actions of IL-1beta and/or by pro-apoptotic mechanisms is an important question for future studies.

Natural infection of a homozygous delta24 CCR5 red-capped mangabey with an R2b-tropic simian immunodeficiency virus

A homozygous 24-bp deletion (Delta24) was found in the CC chemokine receptor 5 (CCR5) of 11 out of 15 red-capped mangabeys (RCMs), Cercocebus torquatus torquatus, both in Africa and in an American zoo. The CCR5 Delta24 defect encompassed eight amino acids in frame in the fourth transmembrane region. Unexpectedly, RCM-009, one of 11 homozygotes (Delta24CCR5/ Delta24CCR5), was found to be naturally infected with a divergent simian immunodeficiency virus (SIV) strain, which was not R5-tropic, but used CCR2b (R2b) as its major coreceptor. SIVrcmGab1 was the only R2b-tropic SIV among other divergent SIVs tested. Cells transfected with the Delta24 CCR5 did not support entry of R5-tropic SIVmac, SIVcpz, SIVmne, HIV-2, or HIV-1, and were also inactive in signal transduction mediated by beta-chemokines. At 86.6%, the Delta24 allelic frequency was significantly higher than that of the 32-bp deletion found in humans. The Delta24 frequency was 4.1% in 34 sooty mangabeys (SMs), a geographically isolated subspecies that was naturally infected with R5-tropic SIV. Finding identical deletions in two mangabey subspecies separated for 10,000 years or more dates the Delta24 CCR5 deletion as ancient. However, the source of the selective pressure for the high rate of CCR5 deletion in RCMs remains to be determined. The high allelic frequency of the Delta24 CCR5 in RCMs, in comparison to that of SMs, suggests that R2b-tropism may have been acquired by SIVrcm, as an adaptation to CCR5 genetic defects appeared in its host.

The amino terminus of human CCR5 is required for its function as a receptor for diverse human and simian immunodeficiency virus envelope glycoproteins

The chemokine receptor CCR5 plays a key role in the CD4-dependent entry of human and simian immunodeficiency viruses into target cells. We have mapped the interaction sites on CCR5 for a number of novel anti-CCR5 monoclonal antibodies and have used these to study the role of the CCR5 N-terminal ectodomain in viral entry and to demonstrate differential CCR5 epitope expression on different cell types. Deletions of the CCR5 amino terminal domain or substitution with equivalent regions from other chemokine receptors did not affect cell surface expression or reactivity with loop-specific antibodies, suggesting that the loop regions remained conformationally intact. Exchanges of the amino terminal segment of CCR5 with the equivalent domains of CCR1, CCR2, and CXCR4 did not significantly affect infection with virus pseudotyped with envelope glycoproteins (Envs) from HIV-2 and SIV, but substitution with the CXCR4 sequence abrogated entry mediated by Env from HIV-1. In contrast, deletion of the amino terminus abrogated CCR5 receptor activity for all viral Envs examined. These data indicate that the amino terminus of CCR5 has an essential role in entry mediated by diverse viral Envs but that the sequence requirements are more relaxed for the HIV-2 and SIV Envs compared to the HIV-1 Env examined. This suggests that different viral Envs make distinct and specific interactions with the amino terminus of CCR5. Viral Env utilization of CCR5 expressed on 293-T cells does not always correlate with the cellular tropism of the virus, and one possible explanation is that Env-accessible interaction sites on CCR5 differ on different cell types. We therefore analyzed binding of several anti-CCR5 monoclonal antibodies to cell lines and primary cells that express this chemokine receptor and found that whereas all antibodies bound to CCR5-transfected 293T cells, several did not bind to PBMC. The results suggest that CCR5 undergoes cell type specific structural modifications which may affect interaction with different HIV and SIV envelope glycoproteins.

Low-level laser irradiation facilitates fibronectin and collagen type I turnover during tooth movement in rats

The aim of this study was to investigate the effects of low-level laser (LLL) irradiation on the turnover of fibronectin and collagen type I in periodontal tissue during tooth movement in rats by immunohistochemistry. Thirty male Sprague-Dawley rats aged 15 weeks were assigned to either an experimental group (n = 15) that underwent LLL irradiation during tooth movement, or a control group (n = 15). In the experimental group, the gallium-aluminum-arsenide (Ga-Al-As) diode LLL (wavelength 808 nm; output 96 mW) was used to irradiate three areas on both the palatal side and the labial side of the maxillary incisor. The radiation was administered by the contact method for 10 s at 0.83 J/cm(2) energy dose, once a day for 7 days. Total energy dose over the complete schedule was 34.86 J/cm(2). The animals were killed on days 1, 3, 7, 14 and 21. There was no difference between the two groups in the amount of tooth movement. The immunohistochemistry results showed that the expression of fibronectin and collagen type I in the experimental group had significantly increased from day 1, with a more even distribution than in the control group, and that this difference was maintained until the end of the experiment. These results suggest that LLL irradiation facilitates the reorganization of the connective tissues during tooth movement in rats.

Tumour-derived Dilp8/INSL3 induces cancer anorexia by regulating feeding neuropeptides via Lgr3/8 in the brain

In patients with advanced-stage cancer, cancer-associated anorexia affects treatment success and patient survival. However, the underlying mechanism is poorly understood. Here, we show that Dilp8, a Drosophila homologue of mammalian insulin-like 3 peptide (INSL3), is secreted from tumour tissues and induces anorexia through the Lgr3 receptor in the brain. Activated Dilp8-Lgr3 signalling upregulated anorexigenic nucleobinding 1 (NUCB1) and downregulated orexigenic short neuropeptide F (sNPF) and NPF expression in the brain. In the cancer condition, the protein expression of Lgr3 and NUCB1 was significantly upregulated in neurons expressing sNPF and NPF. INSL3 levels were increased in tumour-implanted mice and INSL3-treated mouse hypothalamic cells showed Nucb2 upregulation and Npy downregulation. Food consumption was significantly reduced in intracerebrospinal INSL3-injected mice. In patients with pancreatic cancer, higher serum INSL3 levels increased anorexia. These results indicate that tumour-derived Dilp8/INSL3 induces cancer anorexia by regulating feeding hormones through the Lgr3/Lgr8 receptor in Drosophila and mammals.

Prevalence of the enteroaggregative Escherichia coli heat-stable enterotoxin 1 gene and its relationship with fimbrial and enterotoxin genes in E. coli isolated from diarrheic piglets

A total of 720 Escherichia coli strains isolated from diarrheic piglets on 756 swine farms were screened for the presence of the enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1) gene by polymerase chain reaction (PCR). Escherichia coli strains that carried EAST1 genes were also tested by PCR for the presence of 4 fimbriae (F4, F5, F6, F41), 2 heat-stable enterotoxins (STa and STb), and 1 heat-labile enterotoxin (LT) gene. One hundred sixty-four (22.7%) of the 720 E. coli isolates carried genes for EAST1. Of these 164 isolates, 62 (37.8%) carried EAST1 genes only, 11 (6.7%) carried genes for at least 1 of the fimbrial adhesins, 51 (31.1%) carried genes for at least 1 of the enterotoxins, and 40 (23.8%) carried genes for at least 1 of the fimbrial adhesins and enterotoxins. Forty-six percent of strains that carried EAST1 genes carried STa genes, and 16% of strains that carried EAST1 genes carried F4. The isolation rate of enterotoxigenic E. coli strains carrying genes for EAST1 gene was 63%. The 6 major genotypes observed in this study (in decreasing order) were EAST1+, EAST1+STa+, EAST1+STa+STb+, EAST1+STa+F5+, EAST1+STa+F4+, and EAST1+STb+F4+. EAST1 is widely prevalent among diarrheagenic strains of E. coli and may represent an important virulence determinant in the pathogenesis of enteric colibacillosis of preweaned pigs.

Detection and localization of Mycoplasma hyopneumoniae DNA in lungs from naturally infected pigs by in situ hybridization using a digoxigenin-labeled probe

Mycoplasma hyopneumoniae DNA was detected in 20 naturally infected pigs by in situ hybridization using a nonradioactive digoxigenin-labeled DNA probe. A 520-base-pair DNA probe targeting a reiterative sequence of the M. hyopneumoniae genome was generated by the polymerase chain reaction. All 20 pigs infected with M. hyopneumoniae had distinct and positive hybridization signals without background staining. A strong hybridization signal was detected mainly in the luminal surface of bronchial and bronchiolar lining epithelial cells, whereas no hybridization signal was seen in the cytoplasm of bronchial and bronchiolar lining epithelial cells. When hybridization signal was detected in the luminal surface of bronchial and bronchiolar lining epithelial cells, a given bronchus or bronchiole had peribronchiolar lymphoid hyperplastic tissues. Hybridization signals were not seen in the peribronchiolar lymphoid hyperplastic tissues. A less intense signal was detected in the interstitial and alveolar macrophages randomly scattered in the thickened alveolar septa and spaces. Hybridization signal was rarely detected in the type I pneumocytes. The in situ hybridization technique developed in this study was useful for detection of M. hyopneumoniae nucleic acids in tissues taken from naturally infected piglets and may be a valuable technique for studying the pathogenesis of M. hyopneumoniae infection.

Expression of inflammatory cytokines in pigs experimentally infected with Mycoplasma hyopneumoniae

The expression of interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha) and IL-6 were studied over a period of 35 days in the lungs of pigs experimentally infected with Mycoplasma hyopneumoniae, by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), morphometric analysis and in-situ hybridization. Fifteen colostrum-deprived pigs aged 14 days were inoculated intranasally with M. hyopneumoniae. IL-1, TNF-alpha and IL-6 were detected by RT-PCR in the lungs of the infected pigs from 7 days post-inoculation (dpi) onwards, but not in the uninfected control pigs. Concurrent expression of all three cytokines was always observed, in association with lung lesions. Inflammatory cytokine-positive cells were detected in the lungs at 7 dpi, their number increasing at 21dpi, and decreasing thereafter. The results suggest that such cytokines play a role in mediating and regulating inflammation in M. hyopneumoniae infection.

Distribution of tachykinin-related neuropeptide in the developing central nervous system of the moth spodoptera litura

Neuropeptides with similarities to vertebrate tachykinins, designated tachykinin-related peptides (TRPs), have been identified in several insect species. In this investigation we have utilized an antiserum raised to one of the locust TRPs, locustatachykinin-I (LomTK-I), to determine the distribution pattern of LomTK-like immunoreactive (LTKLI) neurons in the developing nervous system of the moth Spodoptera litura. A number of LTKLI neurons could be followed from the larval to the adult nervous system: a set of median neurosecretory cells (MNCs) in the brain, a pair of brain descending neurons and a few sets on neurons in the ventral nerve cord. The distribution of LTKLI neurons in the adult brain is very similar to that seen in other insect species with prominent arborizations in the central body, antennal lobes, mushroom body calyces, optic lobe neuropils and other distinct neuropil areas in the protocerebrum and tritocerebrum. A new finding is the presence of LTKLI neurosecretory cells with axon terminals in the anterior aorta and corpora cardiaca, suggesting for the first time a neurohormonal role of tachykinin-related peptide(s) in insects. During postembryonic development the number of LTKLI neurons in the ventral nerve cord decreases somewhat, whereas the number increases in the brain. Thus the functional roles of TRPs may change to some extent during development.

Hydrogen peroxide triggers the expression of Fas/FasL in astrocytoma cell lines and augments apoptosis

Fas expression increases in perinecrotic areas of glioblastoma. In this study the up-regulation of Fas/FasL by oxidative stress was shown. H(2)O(2) exposure increased Fas expression in two astrocytoma cell lines and cells became sensitive to agonistic anti-Fas antibody. FasL was up-regulated in astrocytoma cells. Apoptosis of Molt-4 cells was augmented by astrocytoma cells pretreated with H(2)O(2). Our findings suggest up-regulation of Fas in astrocytoma cells may lead them to be sensitive to apoptosis when cells are in oxidative stress. Whereas, the up-regulation of FasL may render astrocytoma cells cytotoxic to neighboring brain tissues and infiltrating immune cells.

In-situ hybridization for the detection of inflammatory cytokines (IL-1, TNF-alpha and IL-6) in pigs naturally infected with Actinobacillus pleuropneumoniae

The detection and distribution of interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha) and IL-6 were studied, by in-situ hybridization with a non-radioactive digoxigenin-labelled probe, in formalin-fixed paraffin wax- embedded lung tissue from 10 pigs naturally infected with Actinobacillus pleuropneumoniae. A strong hybridization signal for IL-1, TNF-alpha and IL-6 was detected in "streaming" degenerate alveolar leucocytes (the so-called "oat cells") bordering zones of coagulative necrosis, and a less intense signal was seen in the dense zone of degenerate cells in granulation tissue surrounding the necrotic areas. IL-1 expression was also prominent in scattered endothelial cells bordering zones of coagulative necrosis. Simultaneous expression of all three cytokines was always associated with pleuropneumonic lung lesions. Expression of inflammatory cytokines was minimal in non-lesional lung tissue of the infected pigs and in normal lung from control pigs. The results suggest that these cytokines play a crucial role in mediating and regulating inflammation through cells of several types in A. pleuropneumoniae infection. 1999 Harcourt Publishers Ltd.

Prevalence of genotypes for fimbriae and enterotoxins and of O serogroups in Escherichia coli isolated from diarrheic piglets in Korea

Polymerase chain reaction for 4 fimbriae (F4, F5, F6, F41), 2 heat-stable enterotoxins (STa, STb), and 1 heat-labile enterotoxin (LT) were performed on 400 Escherichia coli isolates to determine their genotype prevalence among enterotoxigenic E. coli isolates from preweaned pigs with diarrhea in the Republic of Korea. A total of 200 of the 400 E. coli isolates were also selected for characterization of the O serogroup. Of these 200 isolates, serogroup could be determined in 139 (69.5%) but not in 61 isolates (30.5%). Isolates of serogroup O101 were the most common, followed in descending order by 08, 020, 0162, 0141, and 0149. Ninety-seven (24.3%) of the 400 E. coli isolates carried genes for at least 1 of the entertoxins or fimbrial adhesins. Of these 97 isolates, 27 carried genes for at least 1 of the fimbrial adhesins and entertoxins. Sixty-six percent of the isolates that carried fimbrial adhesin genes carried genes for at least 1 of the enterotoxins, and 71% of the isolates that carried enterotoxin genes carried genes for at least 1 of the fimbrial adhesins. Genes for the F6 fimbriae were detected in 6% of the E. coli isolates, and F4+, F41+, and F5+ genes were detected in 4.3%, 3.3%, and 2% of the isolates, respectively. Genes for STa, STb, and LT were detected in 10%, 8.5%, and 4.3% of the isolates, respectively. The 6 major genotypes observed in this study (in decreasing order) were F6+, STb+, F41+, STa+STb+, F6+STa+, and STa+.

Injection of skeletal muscle-derived cells into the penis improves erectile function

We investigated the effect of intrapenile injection of muscle-derived cells (MDC) on the erectile function in rats with bilateral cavernous nerve injury. Rat MDC were harvested and transduced with a retrovirus expressing the lacZ gene. Hanks' balanced salt solution (HBSS) (20 microl) or MDC (1 x 10(6) cells/side) were injected in each corpora cavernosa immediately before bilateral cavernous nerve transection. Intracavernous pressures (ICP) were measured 2 or 4 weeks after surgery with electrical stimulation of the pelvic nerves. Mean maximal ICP of sham group was significantly lower than that of control group both at 2 and 4 weeks after surgery. When MDC were injected into the penis, ICP improved over the sham-injected group at both 2 and 4 weeks after surgery. Percent area of PGP 9.5 staining was significantly greater in MDC-injected penis than in sham-injected at 2 and 4 weeks. Penile MDC injection can facilitate recovery of injured penile innervation and improve erectile function.

Chronologic Localization ofMycoplasma hyopneumoniaein Experimentally Infected Pigs

The chronologic localization of Mycoplasma hyopneumoniae was examined by in situ hybridization in experimentally infected pigs for a period of 35 days after intratracheal inoculation. M. hyopneumoniae DNA was detected in bronchial and bronchiolar epithelial cells from infected pigs at 7, 14, 21, and 28 days postinoculation (DPI) and in alveolar and interstitial macrophages and type I pneumocytes from infected pigs at 14, 21, 28, and 35 DPI. Strong hybridization signals for M. hyopneumoniae were detected mainly at the luminal surface of bronchial and bronchiolar lining epithelial cells. When a hybridization signal was detected at the luminal surface of bronchial and bronchiolar lining epithelial cells, a given bronchus or bronchiole also exhibited peribronchiolar lymphoid cuffing. These observations suggested that the presence of M. hyopneumoniae in different tissues could be due to a difference in the duration of the infection.

p38 mitogen-activated protein kinase modulates expression of tumor necrosis factor-related apoptosis-inducing ligand induced by interferon-gamma in fetal brain astrocytes

This study describes the involvement of the p38 mitogen-activated protein kinase (MAPK) during interferon-gamma (IFN-gamma) signaling in fetal brain astrocytes. In some pathological conditions of brain, p38 MAPK transduces stress-related signals, increases expression of proinflammatory cytokines, and induces cellular damage or apoptosis. In astrocytes, the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) expression level was increased by IFN-gamma. AG490, a JAK inhibitor, blocked TRAIL expression induced by IFN-gamma. SB203580, a specific p38alpha and p38beta2 MAPK inhibitor, decreased the TRAIL expression induced by IFN-gamma. The phosphorylation of the Ser727 site of STAT1, but not the Tyr701 site, was inhibited by SB203580. These results suggest that p38 MAPK modulates STAT1 phosphorylation in IFN-gamma signaling in fetal brain astrocytes.

Genotypic prevalence of the fimbrial adhesins (F4, F5, F6, F41 and F18) and toxins (LT, STa, STb and STx2e) in Escherichia coli isolated from postweaning pigs with diarrhoea or oedema disease in Korea

A PCR was used to determine the genotypic prevalence of five fimbrial adhesins (F4, F5, F6, F41 and F18), two heat-stable enterotoxins (STa and STb), the heat-labile enterotoxin (LT), and the shiga toxin 2e (Stx2e) in 230 isolates of Escherichia coli from postweaning pigs with diarrhoea or oedema disease. Ninety-four (40.9 per cent) of the isolates carried genes for at least one of the fimbrial adhesins or toxins. Genes for the F18 fimbrial adhesin were detected in 18.3 per cent, and genes for F4, F6, F5 and F41 were detected in 10.0 per cent, 4.3 per cent, 1.7 per cent and 0.8 per cent of the isolates, respectively. Genes for STa, STb and LT were detected in 25.7 per cent, 15.2 per cent and 8.7 per cent of the isolates, respectively. Genes for Stx2e were detected in 36 (15.6 per cent) of the isolates, and among them 24 also contained the gene for F18ab and four also contained the gene for F18ac.

Survey of knowledge, attitudes and practices for tuberculosis among general practitioners

SETTING

Representative sample survey of knowledge, attitudes and practices (KAP) for tuberculosis among private general practitioners (GPs) in 1993 in Korea,

OBJECTIVE

To investigate the KAP of general practitioners on the prevention and treatment of tuberculosis.

DESIGN

Questionnaire surveys were performed for 923 private general practitioners through 29 health centres.

RESULTS

49% of GPs considered that the Korean tuberculosis situation is not serious. 54% were worried about infection from patients. 47% answered that BCG vaccination causes untoward reactions with no or limited effectiveness. 47% considered the National Tuberculosis Programme (NTP) unfavourably. Over 50% did not consider sputum examination essential in case finding/diagnosis, and 75% in monitoring of treatment response. For initial treatment of active tuberculosis, only 11% were prescribing the current Korean NTP's six-month standard regimen. 73% were giving currently non-recommendable regimens, and 16% unacceptably bad regimens. However, this situation could be improved, as 80% of GPs expressed the wish to acquire knowledge.

CONCLUSION

Many misunderstandings were found in the field of transmission, BCG vaccination and the performance of the NTP; sputum examinations were considerably neglected in case finding/diagnosis and treatment monitoring. As for treatment, 89% were giving either non-recommendable regimens or bad regimens.

Diarrhoea in nursing piglets associated with coccidiosis: prevalence, microscopic lesions and coexisting microorganisms

A retrospective study was made of natural infections with Isospora suis in nursing piglets, recorded from April 1994 to May 1997, to determine the prevalence, microscopical lesions and other microorganisms associated with coccidiosis. One hundred and five (17.3 per cent) of the 605 nursing piglets submitted from 304 pig farms were diagnosed positive for coccidiosis. The affected piglets were from seven to 20 days old, with a mean age of 11.1 days. Coccidiosis occurred in each year but the incidence peaked in July (15 cases, 14.3 per cent), September (15 cases, 14.3 per cent), October (16 cases, 15.2 per cent) and November (18 cases, 17.1 per cent) and was lowest in May (no cases), August (two cases, 1.9 per cent) and June (four cases, 3.8 per cent). Histopathologically, villous atrophy resulting from the necrosis and sloughing of epithelial cells was a prominent feature of infection with I suis. In 49.5 per cent of the nursing piglets, other enteropathogens were identified, Escherichia coli (47.6 per cent) and transmissible gastroenteritis virus (3.8 per cent) being the most commonly diagnosed. Forty-five of 50 E coli isolates associated with coccidiosis tested negative by polymerase chain reaction for enterotoxigenic virulence factors, such as fimbriae and enterotoxins.

Three-dimensional magnetic resonance-based morphometrics and ventricular dysmorphology in schizophrenia

BACKGROUND

Recent methodological refinements in magnetic resonance (MR) imaging have led to brain averaging and morphometric approaches that are sensitive to subtle anatomical distinctions in schizophrenia.

METHODS

Using a novel morphometric technique for surface analysis, 48 selected landmarks of the rendered ventricular system were extracted and compared between the ventricles of 20 patients with schizophrenia and 20 normal subjects.

RESULTS

There was no significant difference in ventricular shape between groups, but significant (p = .015) and highly localized shape deformity was detected at the foramen of Monro and at the proximal temporal horn of the lateral ventricle of male (but not female) patients relative to controls.

CONCLUSIONS

Three-dimensional MR-based morphometrics complements established volumetric approaches and can detect minute shape deformities that may be associated with schizophrenia.

Evidence for an in vivo role of insulin-like growth factor-binding protein-1 and -2 as inhibitors of collagen gene expression in vitamin C-deficient and fasted guinea pigs

Acutely scorbutic and fasted (vitamin C-supplemented) guinea pigs exhibit decreased collagen gene expression associated with weight loss. We recently demonstrated that circulating insulin-like growth factor-binding protein-1 and -2 (IGFBP-1 and -2) are induced in these deficiencies, and that removal of IGFBP-1 and -2 from serum of such animals by specific antibodies reverses inhibition of cellular IGF-I-dependent functions, including collagen and DNA synthesis. Here we investigated the kinetics of induction of IGFBP-1 and -2 relative to suppression of collagen gene expression. Guinea pigs were fasted for 10-96 h, with 3-24% weight loss, or received an ascorbate-free diet for up to 4 weeks, with 5-28% weight loss during the third and fourth weeks (phase II of scurvy). In both deficiencies, there was noncoordinate regulation of collagen mRNA expression in tissues. Type I collagen mRNA concentrations in skin decreased rapidly after 5-10% weight loss and reached about 10% of normal levels, whereas in bone, there was a later, and not as extensive, decrease. The concentration of cartilage type II collagen mRNA decreased rapidly initially, but then remained at 40-50% of normal. Circulating IGF-I concentrations remained normal during the period when collagen gene expression was initially suppressed, although there was a later decrease. In contrast, mRNAs for IGFBP-1 and -2 and the circulating proteins were induced before or concomitantly with the suppression of collagen gene expression. The ability of fasted or scorbutic guinea pig sera to inhibit IGF-I action in cells increased in parallel with IGFBP activity ([125I]IGF-I binding), which, in turn, mainly reflected the concentration of IGFBP-1 in sera. Serum insulin may be the primary regulator of the IGFBPs. Its levels were decreased to 10-13% of normal when weight loss commenced, whereas cortisol levels, although increased, did not correlate with the induction of IGFBPs. The overall results taken together with our recent findings from cell culture experiments are compatible with circulating IGFBP-1 and -2 acting as inhibitors of collagen gene expression by blocking IGF-I action during fasting and phase II of vitamin C deficiency.

Racial and Ethnic Disparities in the Pediatric Hodgkin Lymphoma Population

BACKGROUND

Little is known about the association between race/ethnicity and survival in pediatric Hodgkin lymphoma (HL) patients. In a state-wide pediatric cohort diagnosed with HL, we assessed demographic, disease, and treatment characteristics associated with overall survival (OS). We then attempted to validate these findings and assess disease-specific survival (DSS) in a national Surveillance, Epidemiology, and End Results (SEER) cohort.

PROCEDURE

HL patients of 0.1-21 years diagnosed from 1981 to 2010 were evaluated using the Florida Cancer Data System (FCDS). Kaplan-Meier curves estimated OS from 5 to 25 years based on race/ethnicity, treatment, decade of diagnosis, and sex. Multivariate Cox proportional hazard regressions tested independent factors associated with differences in OS. These methods were replicated in the SEER with additional assessment of DSS.

RESULTS

A total of 1,778 patients were identified in the FCDS and 6,027 in the SEER. Median diagnosis age was 17 years in both cohorts. In the FCDS, Blacks had worse OS than Whites and Hispanics at 25 years (33% vs. 49.2% vs. 44.7%, respectively; P = 0.0005), and Black race was associated with inferior OS on multivariate regression (hazard ratio [HR]: 1.81, P = 0.0003). In the SEER, Blacks had inferior OS (Blacks 74.2% vs. Whites 82% vs. Hispanics 82%; P = 0.0005) and DSS (85.7% vs. 90.8% vs. 88.1%, respectively; P = 0.0002) at 25 years. Hispanic males had inferior DSS compared to White males (84.8% vs. 90.6%; P = 0.0478), and Hispanic race was a predictor for inferior DSS on multivariate analysis (HR: 1.238; P < 0.0001).

CONCLUSIONS

Racial/ethnic disparities persist in the pediatric HL population despite modern treatment; underlying causes of these disparities are complex and need further examination.

Structural domains of IS10 transposase and reconstitution of transposition activity from proteolytic fragments lacking an interdomain linker

All of the DNA cleavage and strand transfer events required for transposition of insertion sequence IS10 are carried out by a 46-kDa IS10-encoded transposase protein. Limited proteolysis demonstrates that transposase has two principal structural domains, a 28-kDa N-terminal domain (N alpha beta; aa 1-246) and a 17-kDa C-terminal domain (C; aa 256-402). The two domains are connected by a 1-kDa proteolytic-sensitive linker region (aa 247-255). The N-terminal domain N alpha beta can be further subdivided into domains N alpha and N beta by a weaker protease-sensitive site located 6 kDa (53 aa) from the N terminus. The N beta and N alpha beta fragments are capable of nonspecific DNA binding as determined by Southwestern blot analysis. None of the fragments alone is capable of carrying out the first step of transposition, assembly of a synaptic complex containing a pair of transposon ends. Remarkably, complete transposition activity can be reconstituted by mixing fragment N alpha beta and fragment C, with or without the intervening linker region. We infer that the structural integrity of transposase during the transitions involved in the chemical steps of the transposition reaction is maintained independent of the linker, presumably by direct contacts between and among the principal domains. Reconstitution of activity in the absence of the linker region is puzzling, however, because mutations that block strand transfer or affect insertion specificity alter linker region residues. Additional reconstitution experiments demonstrate that the N alpha region is dispensable for formation of a synaptic complex but is required for complexes to undergo cleavage.

Differentiation and characteristics of undifferentiated mesenchymal stem cells originating from adult premolar periodontal ligaments

Objective

The purpose of this study was to investigate the isolation and characterization of multipotent human periodontal ligament (PDL) stem cells and to assess their ability to differentiate into bone, cartilage, and adipose tissue.

Methods

PDL stem cells were isolated from 7 extracted human premolar teeth. Human PDL cells were expanded in culture, stained using anti-CD29, -CD34, -CD44, and -STRO-1 antibodies, and sorted by fluorescent activated cell sorting (FACS). Gingival fibroblasts (GFs) served as a positive control. PDL stem cells and GFs were cultured using standard conditions conducive for osteogenic, chondrogenic, or adipogenic differentiation.

Results

An average of 152.8 ± 27.6 colony-forming units was present at day 7 in cultures of PDL stem cells. At day 4, PDL stem cells exhibited a significant increase in proliferation (p < 0.05), reaching nearly double the proliferation rate of GFs. About 5.6 ± 4.5% of cells in human PDL tissues were strongly STRO-1-positive. In osteogenic cultures, calcium nodules were observed by day 21 in PDL stem cells, which showed more intense calcium staining than GF cultures. In adipogenic cultures, both cell populations showed positive Oil Red O staining by day 21. Additionally, in chondrogenic cultures, PDL stem cells expressed collagen type II by day 21.

Conclusions

The PDL contains multipotent stem cells that have the potential to differentiate into osteoblasts, chondrocytes, and adipocytes. This adult PDL stem cell population can be utilized as potential sources of PDL in tissue engineering applications.