CD34+ human marrow cells that express low levels of Kit protein are enriched for long-term marrow-engrafting cells

Using in utero transplantation into fetal sheep, we examined the capability of human bone marrow CD34+ cells fractionated based on Kit protein expression to provide long-term in vivo engraftment. Twelve hundred to 5,000 CD34+ Kit-, CD34+ Kit(low), and CD34+ Kit(high) cells were injected into a total of 14 preimmune fetal sheep recipients using the amniotic bubble technique. Six fetuses were killed in utero 1.5 months after bone marrow cell transplantation. Two fetuses receiving CD34+ Kit(low) cells showed signs of engraftment according to analysis of CD45+ cells in their bone marrow cells and karyotype studies of the colonies grown in methylcellulose culture. In contrast, two fetuses receiving CD34+ Kit(high) cells and two fetuses receiving CD34+ Kit- cells failed to show evidence of significant engraftment. Two fetuses were absorbed. A total of six fetuses receiving different cell populations were allowed to proceed to term, and the newborn sheep were serially examined for the presence of chimerism. Again, only the two sheep receiving CD34+ Kit(low) cells exhibited signs of engraftment upon serial examination. Earlier in studies of murine hematopoiesis, we have shown stage-specific changes in Kit expression by the progenitors. The studies of human cells reported here are in agreement with observations in mice, and indicate that human hematopoietic stem cells are enriched in the Kit(low) population.     

Dummies and the sudden infant death syndrome

The association between dummy use and sudden infant death syndrome (SIDS) was investigated in 485 deaths due to SIDS in the postneonatal age group and compared with 1800 control infants. Parental interviews were completed in 87% of subjects. The prevalence of dummy use in New Zealand is low and varies within New Zealand. Dummy use in the two week period before death was less in cases of SIDS than in the last two weeks for controls (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.57 to 1.02). Use of a dummy in the last sleep for cases of SIDS or in the nominated sleep for controls was significantly less in cases than controls (OR 0.44, 95% CI 0.26 to 0.73). The OR changed very little after controlling for a wide range of potential confounders. It is concluded that dummy use may protect against SIDS, but this observation needs to be repeated before dummies can be recommended for this purpose. If dummy sucking is protective then it is one of several factors that may explain the higher mortality from SIDS in New Zealand than in other countries, and may also explain in part the regional variation within New Zealand.     

Gender and the sudden infant death syndrome

Abstract A nationwide case-control study compared the prevalence and magnitude of risk factors for sudden infant death syndrome (SIDS) in male and female infants. The risk factors of SIDS and their magnitude for males and females are very similar. After adjustment for potential confounders male infants had a 1.42-fold (95% CI = 1.04, 1.94) increased risk of SIDS compared with females. Risk factors identified in most epidemiological studies are not the reason for the increased SIDS mortality seen in male infants.     

Redox-Active Mn Porphyrin-based Potent SOD Mimic,MnTnBuOE-2-PyP<Superscript>5+</Superscript>, Enhances Carbenoxolone-Mediated TRAIL-Induced Apoptosis in Glioblastoma Multiforme

Glioblastoma multiforme is the most malignant tumor of the brain and is challenging to treat due to its highly invasive nature and heterogeneity. Malignant brain tumor displays high metabolic activity which perturbs its redox environment and in turn translates to high oxidative stress. Thus, pushing the oxidative stress level to achieve the maximum tolerable threshold that induces cell death is a potential strategy for cancer therapy. Previously, we have shown that gap junction inhibitor, carbenoxolone (CBX), is capable of enhancing tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) -induced apoptosis in glioma cells. Since CBX is known to induce oxidative stress, we hypothesized that the addition of another potent mediator of oxidative stress, powerful SOD mimic MnTnBuOE-2-PyP⁵⁺ (MnBuOE), could further enhance TRAIL-driven therapeutic efficacy in glioma cells. Our results showed that combining TRAIL + CBX with MnBuOE significantly enhances cell death of glioma cell lines and this enhancement could be further potentiated by CBX pretreatment. MnBuOE-driven cytotoxicity is due to its ability to take advantage of oxidative stress imposed by CBX + TRAIL system, and enhance it in the presence of endogenous reductants, ascorbate and thiol, thereby producing cytotoxic H₂O₂, and in turn inducing death of glioma cells but not normal astrocytes. Most importantly, combination treatment significantly reduces viability of TRAIL-resistant Asian patient-derived glioma cells, thus demonstrating the potential clinical use of our therapeutic system. It was reported that H₂O₂ is involved in membrane depolarization-based sensitization of cancer cells toward TRAIL. MnBuOE is entering Clinical Trials as a normal brain radioprotector in glioma patients at Duke University increasing Clinical relevance of our studies.     

Further evidence for an imprinted gene for neonatal diabetes localised to chromosome 6q22-q23

Transient neonatal diabetes mellitus (TNDM) is a rare form of childhood diabetes which usually resolves in the first 6 months of life but which predisposes to type 2 diabetes of adult onset. We recently reported paternal uniparental isodisomy of chromosome 6 (UPD6) in two children with TNDM and proposed that there may be an imprinted gene important in the aetiology of diabetes on chromosome 6. We now describe two unrelated families which independently suggest that the gene is imprinted, is paternally expressed and maps to 6q22-q23. One family has a duplication while the other, with familial TNDM, shows linkage to a marker in this region.      

Circulating Inflammatory Mediators in Patients with Fever: Predicting Bloodstream Infection

The systemic host response to microbial infection involves clinical signs and symptoms of infection, including fever and elevated white blood cell (WBC) counts. In addition, inflammatory mediators are released, including activated complement product C3a, interleukin 6 (IL-6), and the acute-phase reactant secretory phospholipase A₂ (sPLA₂). To compare the value of the latter with the former in predicting (the degree of) microbial infection at the bedside, we determined clinical variables and took blood samples daily for 3 consecutive days in 300 patients with a new fever (>38.0°C rectally or >38.3°C axillary). Microbiological culture results for 7 days after inclusion were collected. Patients were divided into clinical and microbial categories: those without and with a clinical focus of infection and those with negative cultures, with positive local cultures or specific stains for fungal (n = 13) or tuberculous infections (n = 1), and with positive blood cultures, including one patient with malaria parasitemia. The area under the curve (AUC) of the receiver operating characteristic (ROC) for prediction of positive cultures was 0.60 (P < 0.005) for peak temperature and 0.59 (P < 0.01) for peak WBC count, 0.60 (P < 0.005) for peak C3a, 0.63 (P < 0.001) for peak IL-6, and 0.61 (P < 0.001) for peak sPLA₂. The AUC under the ROC curve for prediction of positive blood cultures was 0.68 (P < 0.001) for peak temperature and 0.56 for peak WBC count (P < 0.05). The AUC for peak C3a was 0.69, that for peak IL-6 was 0.70, and that for sPLA₂ was 0.67 (for all, P < 0.001). The degree of microbial invasion is thus a major determinant of the clinical and inflammatory host response in patients with fever. Moreover, circulating inflammatory mediators such as C3a and IL-6 may help to predict positive blood cultures, together with clinical signs and symptoms of the host response to microbial infection, even before culture results are available. This may help in the designing of entry criteria for therapeutic intervention studies.     

BGC20-1531, a novel,potent and selective prostanoid EP4 receptor antagonist: a putative new treatment for migraine headache

Background and purpose:

Prostanoid EP₄ receptor antagonists may have therapeutic utility in the treatment of migraine since EP₄ receptors have been shown to be involved in prostaglandin (PG)E₂-induced cerebral vascular dilatation, which may be an important contributor to migraine pain. This study reports the pharmacological characterization of BGC20-1531, a novel EP₄ receptor antagonist.

Experimental approach:

BGC20-1531 was characterized in radioligand binding and in vitro functional assays employing recombinant and native EP₄ receptors. Changes in canine carotid haemodynamics were used to assess the pharmacodynamic profile of BGC20-1531 in vivo.

Key results:

BGC20-1531 exhibited high affinity at recombinant human EP₄ receptors expressed in cell lines (pK_B 7.6) and native EP₄ receptors in human cerebral and meningeal artery (pK_B 7.6–7.8) but showed no appreciable affinity at a wide range of other receptors (including other prostanoid receptors), channels, transporters and enzymes (pKi < 5). BGC20-1531 competitively antagonized PGE₂-induced vasodilatation of human middle cerebral (pK_B 7.8) and meningeal (pK_B 7.6) arteries in vitro, but had no effect on responses induced by PGE₂ on coronary, pulmonary or renal arteries in vitro. BGC20-1531 (1–10 mg·kg⁻¹ i.v.) caused a dose-dependent antagonism of the PGE₂-induced increase in canine carotid blood flow in vivo.

Conclusions and implications:

BGC20-1531 is a potent and selective antagonist at EP₄ receptors in vitro and in vivo, with the potential to alleviate the symptoms of migraine that result from cerebral vasodilatation. BGC20-1531 is currently in clinical development for the treatment of migraine headache.     

Cyclic AMP-mediated chloride secretion is induced by prostaglandin F2α in human isolated colon

Background and purpose:

Prostaglandin F_2α (PGF_2α) is implicated in the pathogenesis of inflammatory bowel disease and colorectal cancer. This study investigates the effects of PGF_2α on electrophysiological parameters in isolated human colonic mucosa.

Experimental approach:

Ion transport was measured as changes in short-circuit current across human colonic epithelia mounted in Ussing chambers. Colonic crypts were isolated by calcium chelation and cyclic adenosine monophosphate (cAMP) was measured by ELISA.

Key Results:

PGF_2α stimulated chloride secretion in a concentration-dependent manner with an EC₅₀ of 130 nM. The PGF_2α induced increase in chloride secretion was inhibited by AL8810 (10 µM), a specific PGF_2α receptor antagonist. In addition, PGF_2α (1 µM) significantly increased levels of cAMP in isolated colonic crypts.

Conclusions and implications:

PGF_2α stimulated chloride secretion in samples of human colon in vitro through a previously unrecognizd cAMP-mediated mechanism. These findings have implications for inflammatory states.     

Effect of tuberculin skin testing on a Mycobacterium tuberculosis-specific interferon-gamma assay.

Recently, interferon-gamma release assays (IGRA) for specific diagnosis of Mycobacterium tuberculosis infection have become available. In recent UK tuberculosis (TB) guidelines, it has been advised to screen for latent M. tuberculosis infection using the tuberculin skin test (TST), followed by IGRA if the TST is positive. Since TST can boost immune responses to tuberculin, the present authors evaluated whether TST administration affects the result of QuantiFERON-TB Gold in-tube (QFT-GIT), a whole blood-based IGRA. QFT-GIT was performed on the day of TST administration and the day of reading in 15 TST-negative subjects, 46 TST-positive subjects with recent or remote exposure to M. tuberculosis and five cured TB patients. No systematic boosting of QFT-GIT responses from negative to positive was observed. Only in a few TST-positive persons did TST enhance pre-existing QFT-GIT responses. Screening for latent Mycobacterium tuberculosis infection using tuberculin skin testing followed by interferon-gamma release assays on the day of reading is a reliable approach, as the specificity of QuantiFERON-TB Gold in-tube is not affected by prior tuberculin skin test administration.     

SIDS, illness, and acute medical care. New Zealand Cot Death Study Group

One component of the Back to Sleep campaign to reduce the risk of sudden infant death syndrome (SIDS) is the recommendation that parents seek medical attention if their infant is unwell. The aim of this study was to investigate of SIDS could in part be explained by sick infants not getting appropriate medical care. Data on symptoms of illness and on acute medical contacts made for infants dying from SIDS (n = 390) within two weeks of their death were compared with those from a randomly selected group of control infants (n = 1592). SIDS cases had more severe illness than controls (odds ratio (OR) = 3.43; 95% confidence interval (CI) = 1.69 to 5.38), and were more likely to have seen a general practitioner (OR = 1.37; 95% CI = 1.09 to 1.73) or attended hospital (OR = 3.43, 95% CI = 1.09 to 1.73). Only 1.3% of all SIDS cases had symptoms suggesting severe illness and had not seen a general practitioner. A lack of medical contacts in the two weeks before death does not contribute to the risk of SIDS.