Circulating microRNAs Are Associated With Metabolic Markers in Adolescents With Hepatosteatosis

BACKGROUND

Altered hepatic microRNA (miRNA) expression may play a role in the development of insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD). Circulating miRNAs could mirror the liver metabolism.

OBJECTIVE

This study aimed to assess the relationship between serum miRNA profile in children with obesity, IR, and NAFLD.

METHODS

Adolescents with obesity (n = 31) were stratified based on insulin resistance and NAFLD status. One-hundred seventy-nine miRNAs were determined in the serum by quantitative RT-PCR. Differentially expressed miRNAs were compared between groups, and log-transformed levels correlated with metabolic markers and intrahepatic triglyceride.

RESULTS

Serum miR-21-5p, -22-3p, -150-5p, and -155-5p levels were higher in children with IR and NAFLD, and their expression levels correlated with hepatic fat and serum triglyceride. In patients with NAFLD, miR-155-5p correlated with ALT (r = 0.68, p<0.01) and AST (r = 0.64, p<0.01) and miR-21-5p and -22-3p levels correlated with plasma adiponectin (r = -0.71 and r = -0.75, respectively, p<0.05) and fibroblast growth factor-21 (r = -0.73 and r = -0.89, respectively, p<0.01). miR-27-3a level was higher in children without IR and NAFLD.

CONCLUSIONS

Several miRNAs are differentially expressed in children with IR and NAFLD. Determining their mechanistic roles may provide newer diagnostic tools and therapeutic targets for pediatric NAFLD.

Partner bereavement and risk of psoriasis and atopic eczema: cohort studies in the U.K. and Denmark

BACKGROUND

Stress is commonly cited as a risk factor for psoriasis and atopic eczema, but such evidence is limited.

OBJECTIVES

To investigate the association between partner bereavement (an extreme life stressor) and psoriasis or atopic eczema.

METHODS

We conducted cohort studies using data from the U.K. Clinical Practice Research Datalink (1997-2017) and Danish nationwide registries (1997-2016). The exposed cohort was partners who experienced partner bereavement. The comparison cohort was up to 10 nonbereaved partners, matched to each bereaved partner by age, sex, county of residence (Denmark) and general practice (U.K.). Outcomes were the first recorded diagnosis of psoriasis or atopic eczema. We estimated hazard ratios (HRs) and confidence intervals (CIs) using a stratified Cox proportional hazards model in both settings, which were then pooled in a meta-analysis.

RESULTS

The pooled adjusted HR for the association between bereavement and psoriasis was 1·01 (95% CI 0·98-1·04) across the entire follow-up. Similar results were found in other shorter follow-up periods. Pooled adjusted HRs for the association between bereavement and atopic eczema were 0·97 (95% CI 0·84-1·12) across the entire follow-up, 1·09 (95% CI 0·86-1·38) within 0-30 days, 1·18 (95% CI 1·04-1·35) within 0-90 days, 1·14 (95% CI 1·06-1·22) within 0-365 days and 1·07 (95% CI 1·02-1·12) within 0-1095 days.

CONCLUSIONS

We found a modest increase in the risk of atopic eczema within 3 years following bereavement, which peaked in the first 3 months. Acute stress may play a role in triggering onset of new atopic eczema or relapse of atopic eczema previously in remission. We observed no evidence for increased long-term risk of psoriasis and atopic eczema following bereavement.

Fibroblast Growth Factor-21 to Adiponectin Ratio: A Potential Biomarker to Monitor Liver Fat in Children With Obesity

Background: There is a pressing need for effective and non-invasive biomarkers to track intrahepatic triglyceride (IHTG) in children at-risk for non-alcoholic fatty liver disease (NAFLD), as standard-of-care reference tools, liver biopsy and magnetic resonance imaging (MRI), are impractical to monitor the course disease. Objective: We aimed to examine the association between serum fibroblast growth factor (FGF)-21 to adiponectin ratio (FAR) and IHTG as assessed by MRI in children with obesity. Methods: Serum FGF21 and adiponectin levels and IHTG were measured at two time points (baseline, 6 months) in obese children enrolled in a clinical weight loss program. The association between percent change in FAR and IHTG at final visit was examined using a multiple linear regression model. Results: At baseline, FAR was higher in the subjects with NAFLD (n = 23, 35.8 ± 41.9 pg/ng) than without NAFLD (n = 35, 19.8 ± 13.7 pg/ng; p = 0.042). Forty-eight subjects completed both visits and were divided into IHTG loss (≥1% reduction than baseline), no change (within ±1% change), and gain (≥1% increase than baseline) groups. At 6 months, the percent change in FAR was different among the three groups (p = 0.005). Multiple linear regression showed a positive relationship between percent change in FAR and the final liver fat percent in sex and pubertal stage-similar subjects with NAFLD at baseline (slope coefficient 6.18, 95% CI 1.90-10.47, P = 0.007), but not in those without NAFLD. Conclusions: Higher value in percent increase in FAR is positively associated with higher level of IHTG percent value at 6 months in children with baseline NAFLD. FAR could be a potential biomarker to monitor the changes in IHTG in children with NAFLD.

Emerging and reemerging infectious diseases of nonhuman primates in the laboratory setting

Despite numerous advances in the diagnosis and control of infectious diseases of nonhuman primates in the laboratory setting, a number of infectious agents continue to plague colonies. Some, such as measles virus and Mycobacterium tuberculosis, cause sporadic outbreaks despite well-established biosecurity protocols, whereas others, such as retroperitoneal fibromatosis-associated herpesvirus, have only recently been discovered, often as a result of immunosuppressive experimental manipulation. Owing to the unique social housing requirements of nonhuman primates, importation of foreign-bred animals, and lack of antemortem diagnostic assays for many new diseases, elimination of these agents is often difficult or impractical. Recognition of these diseases is therefore essential because of their confounding effects on experimental data, impact on colony health, and potential for zoonotic transmission. This review summarizes the relevant pathology and pathogenesis of emerging and reemerging infectious diseases of laboratory nonhuman primates.

Experimental infection of serotine bats (Eptesicus serotinus) with European bat lyssavirus type 1a

The serotine bat (Eptesicus serotinus) accounts for the vast majority of bat rabies cases in Europe and is considered the main reservoir for European bat lyssavirus type 1 (EBLV-1, genotype 5). However, so far the disease has not been investigated in its native host under experimental conditions. To assess viral virulence, dissemination and probable means of transmission, captive bats were infected experimentally with an EBLV-1a virus isolated from a naturally infected conspecific from Germany. Twenty-nine wild caught bats were divided into five groups and inoculated by intracranial (i.c.), intramuscular (i.m.) or subcutaneous (s.c.) injection or by intranasal (i.n.) inoculation to mimic the various potential routes of infection. One group of bats was maintained as uninfected controls. Mortality was highest in the i.c.-infected animals, followed by the s.c. and i.m. groups. Incubation periods varied from 7 to 26 days depending on the route of infection. Rabies did not develop in the i.n. group or in the negative-control group. None of the infected bats seroconverted. Viral antigen was detected in more than 50% of the taste buds of an i.c.-infected animal. Shedding of viable virus was measured by virus isolation in cell culture for one bat from the s.c. group at 13 and 14 days post-inoculation, i.e. 7 days before death. In conclusion, it is postulated that s.c. inoculation, in nature caused by bites, may be an efficient way of transmitting EBLV-1 among free-living serotine bats.

Detection of high levels of European bat lyssavirus type-1 viral RNA in the thyroid gland of experimentally-infected Eptesicus fuscus bats

Two common bat lyssavirus species have been identified in many European countries: European bat lyssavirus type-1 and -2 (EBLV-1 and EBLV-2). Only limited knowledge on the susceptibility of the natural EBLV-hosts, insectivorous bats, to lyssavirus infection is available. Our study was undertaken to evaluate the susceptibility and pathology associated with an EBLV-1 infection in Eptesicus fuscus following different routes of virus inoculation including intracranial (n = 6), intramuscular (n = 14), oral (n = 7) and intranasal (n = 7). Blood and saliva samples were collected from all bats on a monthly basis. Four bats inoculated intracranially developed rabies with a mean of 11 days to death, whilst seven bats inoculated intramuscularly developed rabies, with an extended incubation period prior to death. We did not observe any mortality in the oral (p.o.) or intranasal (i.n.) groups and both groups had detectable levels of virus neutralizing antibodies (data not shown). Virus shedding was demonstrated in the saliva by virus isolation and the detection of viral RNA in ill bats, particularly immediately prior to the development of disease. In addition, the presence of virus and viral RNA was detected in the thyroid gland in bats challenged experimentally with EBLV-1, which exceeded that detected in all other extra-neural tissue. The significance of detecting EBLV-1 in the thyroid gland of rabid bats is not well understood. We speculate that the infection of the thyroid gland may cause subacute thyroiditis, a transient form of thyroiditis causing hyperthyroidism, resulting in changes in adrenocortical activity that could lead to hormonal dysfunction, thereby distinguishing the clinical presentation of rabies in the rabid host.

Normative nerve conductions in the tail of rhesus macaques (Macaca mulatta)

BACKGROUND

The aim of this study was to test the feasibility of using the tail of Macaca mulatta for neurophysiological testing of the peripheral nervous system.

METHODS

Motor and sensory nerve conduction studies (NCS) of the tail were obtained by surface stimulation and recording. The technique utilized was novel. Unlike other NCS obtained from other peripheral nerves, this technique did not require any special neurophysiological expertise.

RESULTS

The latency of the motor and sensory response was 2.5 +/- 0.71 and 1.1 +/- 0.27 ms respectively. The amplitude of the motor and sensory response was 8.1 +/- 5.1 mV and 14.6 +/- 9.4 microV respectively. Similar to human beings, there was a statistically significant relationship between age and motor amplitude, motor latency and sensory latency.

CONCLUSIONS

Based on our results, a relatively simple, reproducible neurophysiological monitoring technique of the peripheral nervous system is possible.

Induction of apoptosis in skeletal tissues: phosphate-mediated chick chondrocyte apoptosis is calcium dependent

In an earlier study, we have shown that Pi induced apoptosis of terminally differentiated hypertrophic chondrocytes. To ascertain whether Ca2+ modulates Pi-induced cell death, we asked the following two questions: First, can we prevent Pi-induced apoptosis by removing Ca2+ from the culture medium; alternatively, can we potentiate cell death by increasing the Ca2+ concentration? Second, can we inhibit chondrocyte apoptosis by blocking Pi transport? We also explored the mechanism of apoptosis by evaluating mitochondrial activity and reactive oxygen species (ROS) generation in cells treated with the ion pair. We noted that EDTA and EGTA blocked Pi-induced apoptosis in a dose-dependent manner. While high levels of Ca2+ alone had little effect on chondrocyte viability, the cation enhanced Pi-dependent cell death and greatly increased Pi uptake. When Pi transport was blocked, there was complete inhibition of cell killing. The process of cell death was characterized by mitochondrial hyperpolarization; two hours following apoptogen treatment, there was a significant decrease in the mitochondrial membrane potential. Coincident with the changes in mitochondrial function, there was an increase in intracellular Ca2+ that was maintained throughout the experimental period. A raised Ca2+ signal was observed in blebs at the cell membrane. Finally, we noted that, 75 minutes after treatment with the ion pair, there was a six-fold elevation in ROS levels. This increase declined to baseline values after three hours. Based on these observations, we suggest that, at the cartilage mineralization front, an elevation in local environmental Ca2+ and Pi concentrations modulates oxidative metabolism, and triggers apoptosis of terminally differentiated chondrocytes.

Acetylation of p53 activates transcription through recruitment of coactivators/histone acetyltransferases

Cellular DNA damage causes stabilization and activation of the tumor suppressor and transcription factor p53, in part by promoting multiple covalent modifications of the p53 protein, including acetylation. We investigated the importance of acetylation in p53 function and the mechanism by which acetylation influences p53 activity. Acetylation site substitutions reduced p53-dependent transcriptional induction and G1 cell cycle arrest. Chromatin immunoprecipitation analysis of the endogenous p21 promoter showed increased association of p53, coactivators (CBP and TRRAP), and acetylated histones following cell irradiation. Results with acetylation-defective p53 demonstrate that the critical function of acetylation is not to increase the DNA binding affinity of p53 but rather to promote coactivator recruitment and histone acetylation. Therefore, we propose that an acetylation cascade consisting of p53 acetylation-dependent recruitment of coactivators/HATs is crucial for p53 function.

Phosphate-induced chondrocyte apoptosis is linked to nitric oxide generation

An elevation in inorganic phosphate (P(i)) concentration activates epiphyseal chondrocyte apoptosis. To determine the mechanism of apoptosis, tibial chondrocytes were treated with P(i), and nitrate/nitrite (NO/NO) levels were determined. P(i) induced a threefold increase in the NO/NO concentration; inhibitors of nitric oxide (NO) synthase activity and P(i) transport significantly reduced NO/NO levels and prevented cell death. Furthermore, a dose-dependent increase in cell death was observed after exposure of chondrocytes to S-nitrosoglutathione. P(i) increased caspase 3 activity 2.7-fold. Both caspase 1 and caspase 3 inhibitors protected chondrocytes from P(i)-induced apoptosis. P(i) caused a significant decrease in the mitochondrial membrane potential, while NO synthase inhibitors maintained mitochondrial function. While P(i) caused thiol depletion, inhibition of P(i) uptake or NO generation served to maintain glutathione levels. The results suggest that NO serves to mediate key metabolic events linked to P(i)-dependent chondrocyte apoptosis.

Matrix regulation of skeletal cell apoptosis. Role of calcium and phosphate ions

Previously, we noted that inorganic phosphate (P(i)), a major component of bone extracellular matrix, induced osteoblast apoptosis (Meleti, Z., Shapiro, I. M., and Adams, C. S. (2000) Bone (NY) 27, 359-366). Since Ca(2+) along with P(i) is released from bone during the resorption process, we advanced the hypothesis that Ca(2+) modulates P(i)-mediated osteoblast apoptosis. To test this hypothesis, osteoblasts were incubated with both ions, and cell death was determined. We noted that a modest increase in the medium Ca(2+) concentrations ([Ca(2+)](e)) of 0.1-1 mm caused a profound and rapid enhancement in P(i)-dependent death of cultured osteoblasts. An elevation in [Ca(2+)](e) alone had no effect on osteoblast viability, whereas Ca(2+) channel blockers failed to inhibit killing of ion pair-treated cells. These results indicated that P(i)-mediated cell death is not dependent on a sustained increase in the cytosolic Ca(2+) concentration. Terminal dUTP nick-end labeling analysis and measurement of caspase-3 activity of the ion pair-treated cells suggested that death was apoptotic. Apoptosis was confirmed using caspase-3 and endonuclease inhibitors. The mitochondrial membrane potential and cytosolic Ca(2+) status of the treated cells were evaluated. After incubation with [Ca(2+) ](e) and P(i), a decrease in mitochondrial fluorescence was noted, suggesting that the ions decreased the mitochondrial transmembrane potential. Subsequent to the fall in mitochondrial membrane potential, there was a transient elevation in the cytosolic Ca(2+) concentration. Results of the study suggest that the ion pair conspire at the level of the plasma membrane to induce intracellular changes that result in loss of mitochondrial function. The subsequent increase in the cytosolic Ca(2+) concentration may trigger downstream events that transduce osteoblast apoptosis.

Phosphate ions mediate chondrocyte apoptosis through a plasma membrane transporter mechanism

In a previous investigation we showed that phosphate ions (Pi) induced apoptosis of terminally differentiated hypertrophic chondrocytes. To explore the mechanism by which Pi induces cell death, we asked the following two questions. First, can we prevent Pi-induced apoptosis by inhibiting plasma membrane Na-Pi cotransport? Second, which specific Na-Pi transporters are expressed in chondrocytes and are they developmentally regulated? Terminally differentiated hypertrophic chondrocytes were isolated from chick tibial cartilage and cell death was measured in the presence of 3-7 mmol/L Pi. To ascertain whether apoptosis was linked to a rise in cellular Pi loading, we examined the effect of phosphonoformic acid (PFA), a competitive inhibitor of Na-Pi cotransport on Pi-induced apoptosis in chondrocytes. We found that 1 mmol/L PFA blocked anion-induced cell death and prevented an increase in the cell Pi content. In a parallel study, we determined that the bisphosphonate, alendronate, also protected chondrocytes from death, albeit at a lower concentration than PFA. Using a DNA end-labeling procedure, we showed that the Pi-treated cells were apoptotic and, as might be predicted, the presence of PFA blocked induction of the death sequence. Next, we examined the expression of two Pi transporters in relation to chondrocyte maturation and anion treatment. We noted that there was expression of the constitutive transporter, Glvr-1, and a type II cotransporter in chick growth plate cells. Although these transport systems are active in terminally differentiated cells, it is probable that the initiation of apoptosis may require the induction of other Pi-transport systems. It is concluded that, at the mineralization front, cell death is linked directly to the elevation in environmental anion concentration and the concomitant rise in intracellular Pi levels.

Attempts to establish experimental Cyclospora cayetanensis infection in laboratory animals

Attempts were made to develop an animal model for Cyclospora cayetanensis to identify a practical laboratory host for studying human cyclosporiasis. Oocysts collected from stool of infected humans in the United States, Haiti, Guatemala, Peru, and Nepal were held in potassium dichromate solution to allow development of sporozoites. The following animal types were inoculated: 9 strains of mice, including adult and neonatal immunocompetent and immune-deficient inbred and outbred strains, rats, sandrats, chickens, ducks, rabbits, jirds, hamsters, ferrets, pigs, dogs, owl monkeys, rhesus monkeys, and cynomolgus monkeys. Most animals were inoculated by gavage, although some of the primates were fed oocysts on food items. The animals were examined for signs of infection, particularly diarrhea, and stool samples were examined for 4-6 wk after inoculation. None of the animals developed patent infections or signs of infection. We conclude that none of the animals tested is susceptible to infection with C. cayetanensis.

Extracellular phosphate ions cause apoptosis of terminally differentiated epiphyseal chondrocytes

Epiphyseal chondrocytes end their life cycle through apoptosis. While this event provides a mechanism for the removal of terminally differentiated cells from cartilage, agents that promote this physiological process have not been defined. To address this issue, using a cell culture technique that models events that take place in the growth plate, we asked the following questions: Can agents that promote chondrocyte maturation and cartilage mineralization serve as specific triggers for cell death? Are chondrocytes susceptible to apoptogens at a singular developmental stage? Treatment of embryonic tibial chondrocytes with inorganic phosphate (Pi) induced death in a dose- and time-dependent manner. Within 48 hr, 3 mM Pi increased chondrocyte death by 30%; lower concentrations of Pi induced death after 48 hr. To ascertain if death was due to apoptosis, we evaluated Pi-induced death by a number of different methods and compared the results to those induced by the apoptogen, staurosporine. Analysis of the death process indicated that cartilage cells shared many of the common biological features of the apoptotic process. Thus, there was DNA fragmentation, terminal deoxynucleotidyl transferase (TUNEL) labeling, an increase in cells in the sub-G1 fraction of the cell cycle, and morphological evidence of apoptosis. To explore the specificity of the Pi effect, the experiment was repeated using embryonic sternal cephalic and caudal chondrocytes, cells that are at an earlier developmental stage than the terminally differentiated tibial cells. We noted that these cells remained vital despite a major increase in the medium Pi content. Results of this study suggest that Pi is a stage-specific inducer of apoptosis in maturing chondrocytes and that this role may be linked to chondrocyte maturation and mineralization of the extracellular matrix.

Chondrocyte death is linked to development of a mitochondrial membrane permeability transition in the growth plate

In the companion article, we reported that the local phosphate (Pi) concentration triggers apoptosis in epiphyseal chondrocytes. The goal of the current investigation was to evaluate the apoptotic process in relationship to the energy status of cells in the growth plate. For these studies, we used sections of the adolescent growth plate, as well as cells isolated from the tissue. We found that there was a maturation-dependent loss of mitochondrial function in growth plate chondrocytes and these cells generated energy by glycolysis. Since treatment with the uncoupler 2,4-dinitrophenol as well as the site-specific inhibitors antimycin A and rotenone failed to elicit a further increase in the activity of the glycolytic pathway, we concluded that oxidative metabolism was minimum in these cells. Flow cytometric studies of growth plate cells and confocal microscopy of growth plate sections using the mitochondrial probes Rh123 and DiOC6(3) provided unequivocal evidence that there was loss of mitochondrial membrane potential in hypertrophic cells. Furthermore, the intrinsic fluorescence of the flavoprotein lipoamide dehydrogenase complex of the electron transport chain revealed that the mitochondria were in an oxidized state. Finally, we assessed Bcl-2 expression in these cells. Although immunohistochemical and Western blot analysis showed that the chick cells contained a low level of the anti-apoptotic protein Bcl-2, reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that transcripts were present in chondrocytes. Based on these observations, we suggest that terminally differentiated chondrocytes undergo a maturation-dependent loss of mitochondrial function. In concert with the low expression of Bcl-2, they become sensitive to signals for programmed cell death. We hypothesize that Pi triggers apoptosis in these energy-compromised cells by promoting a mitochondrial membrane transition, thereby inducing the death process.

Transmission and serial propagation of Enterocytozoon bieneusi from humans and Rhesus macaques in gnotobiotic piglets

For over a decade Enterocytozoon bieneusi infections in people with AIDS have been linked with chronic diarrhea and wasting. The slow scientific progress in treating these infections is attributed to the inability of investigators to cultivate the parasite, which has also precluded evaluation of effective therapies. We report here successful serial transmissions of E. bieneusi from patients with AIDS and from macaques with AIDS to immunosuppressed gnotobiotic piglets. One infected piglet was still excreting spores at necropsy 50 days after an oral challenge. Spores in feces were detected microscopically by trichrome stain and by PCR and within enterocytes by in situ hybridization and immunohistochemistry. E. bieneusi infection induced no symptoms. The development of an animal model for E. bieneusi will open up new opportunities for investigating this parasite.

Activation of sodium transport and intracellular sodium lowering by the neuroleptic drug chlorpromazine

Chlorpromazine (CPZ), a commonly used antipsychotic drug, at high concentration was found to reduce significantly the sodium content of both rat (Rattus norvegicus) and toad (Bufo marinus) liver cells. This reduction in intracellular sodium was demonstrated using 22Na+ flux and measurement of cell sodium content. The results suggest that the sodium-lowering effect of CPZ stemmed from a stimulation of sodium transport rather than from an inhibition of sodium influx (i.e., sodium channels), cell damage, or Na+:Na+ exchange. CPZ was found to interfere with the binding of ouabain to the sodium pump, although a simple reduction in sodium pump inhibition did not account for the sodium-lowering effect. CPZ was able to negate the effects of monensin, a sodium ionophore, suggesting a substantial capacity to activate sodium transport. The intracellular sodium-lowering action of CPZ through the activation of sodium transport represents a new property previously undescribed for this drug.

Development and application of genetic probes for detection of Enterocytozoon bieneusi in formalin-fixed stools and in intestinal biopsy specimens from infected patients

The microsporidium Enterocytozoon bieneusi is closely linked to wasting and diarrhea in a high proportion of individuals with AIDS. However, its relative contribution to disease is uncertain because diagnosis until recently depended on procedures involving endoscopy. A sensitive PCR technique which amplifies a fragment of the small-subunit rRNA gene of E. bieneusi from formalin-fixed stool samples was developed. Of 80 formalin-fixed stool samples collected from 74 Zimbabweans and 6 U.S. patients who were human immunodeficiency virus positive, 50% tested positive for E. bieneusi by PCR, whereas 24% tested positive for E. bieneusi by light microscopy of trichrome-stained fecal smears. In addition, we describe an in situ hybridization technique which detected and identified E. bieneusi as the causative agent in all six intestinal biopsy specimens tested. Both the PCR and in situ hybridization procedures are sensitive diagnostic tools which will complement currently available techniques and enable the differentiation of E. bieneusi from other microsporidia to be made.

Radiographic evaluation of the soap man mummy

This article describes how mobile radiography was used to examine a mummified cadaver exhumed in 1875 and stored in the Smithsonian Museum. Radiographs revealed artifacts imbedded in the cadaver, indicating 1824 as the earliest possible interment. Through radiographic assessment of the skeleton, researchers were able to approximate the individual's age at death. In addition, evidence of pathology, possibly ideopathic skeletal hyperostosis, suggested the individual may have been employed in manual labor. The radiographs, when compared to x-rays of another cadaver exhumed at the same time and place, refuted information in museum records.

Transmission and establishment of a persistent infection of Enterocytozoon bieneusi, derived from a human with AIDS, in simian immunodeficiency virus-infected rhesus monkeys

Enterocytozoon bieneusi is closely linked with chronic diarrhea and wasting in AIDS. Although reported >10 years ago, little is known about the infection and the disease it induces in humans. Duodenal E. bieneusi spores from an AIDS patient were orally transmitted to 2 simian immunodeficiency virus-infected rhesus monkeys. Both animals began shedding spores within a week of inoculation, as confirmed by microscopy and polymerase chain reaction, and continued until euthanatized 7 and 8 months later. E. bieneusi infection in the gut was sparse, either because of moderate numbers of circulating CD4 cells or because monkeys are less susceptible than humans to this infection. This is apparently the first documented transmission of E. bieneusi infection between hosts.

Induction of apoptosis in human T-cells by organomercuric compounds: a flow cytometric analysis

Although several lines of investigation demonstrate that many heavy metals are cytotoxic to host defense cells, the mechanism of killing is poorly understood. The major focus of this investigation was to determine if organic mercuric compounds kill human lymphocytes by inducing the cells to undergo apoptosis and to evaluate possible flow cytometric systems for assessing cell death. T-cells were exposed to 0.6-5 microM MeHgCl, EtHgCl, or PhHgCl for up to 24 hr and then analyzed by flow cytometry. Mercury-treated cells exhibited increased Hoechst 33258 and 33342 fluorescence while maintaining their ability to exclude the vital stain 7-AAD. Furthermore, T-cells exposed to mercury exhibited changes in light scatter patterns that included decreased forward light scatter and increased side scatter. The light scatter and fluorescent changes were consistent with changes that cells display during apoptosis. To further evaluate cell death and to distinguish between apoptosis and necrosis, merocyanine 540 staining and annexin V binding to the plasma membrane as well as DNA fragmentation were assessed. Mercury-treated cells exhibited increased merocyanine 540 fluorescence and annexin V binding along with changes in nuclear morphology consistent with the notion of apoptosis. Conventional agarose gel electrophoresis failed to demonstrate low-molecular-weight DNA bands; however, when probed by flow cytometry using both nick translation and a modified TUNEL assay, patterns consistent with nuclear fragmentation were evident. We noted that the percentage of T-cells undergoing apoptosis was dependent upon the amount of serum present in the medium; as serum concentrations were increased from 0 to 10%, cell death declined. Apoptosis (33%) was observed within 1 hr of exposure to MeHgCl; maximum cell death (67%) occurred after 24 hr exposure. Induction of apoptosis was dependent on the mercury concentration and independent of the hydrophobicity of the mercury ligand. Finally, we assessed mercury-dependent apoptosis in activated T-cells. When treated with mitogen, mercury failed to induce apoptosis in these cells. Indeed, there was no evidence of either apoptosis nor necrosis in these populations. It was concluded that the activation process prevented development of a metabolic state that was required for induction of apoptogenic genes.

Vasoactive intestinal polypeptide and neuropeptide Y act indirectly to increase neurite outgrowth of dissociated dorsal root ganglion cells

Recent studies suggest that rearrangement of synaptic circuitry of primary afferent neurons in the spinal cord may contribute, in part, to hyperalgesia that is often associated with peripheral nerve injury. This study of cultured adult rat dorsal root ganglion cells examined whether vasoactive intestinal polypeptide and neuropeptide Y, which are up-regulated in sensory neurons following nerve transection, possibly contribute to the morphological alterations induced by nerve injury. Neurite outgrowth of dissociated dorsal root ganglion cells was examined two weeks following either sciatic nerve transection or intrathecal administration of test agents via osmotic pumps. Dissociated cells taken from rats with transected sciatic nerve or following intrathecal administration of either vasoactive intestinal polypeptide or neuropeptide Y had a significant increase in the percentage of cells with neurites as compared to dorsal root ganglion cells taken from normal animals. Intrathecal administration, into rats with nerve lesion, of the vasoactive intestinal polypeptide and neuropeptide Y antagonists, vasoactive intestinal polypeptide(10-28) and alpha-trinositol, respectively, significantly attenuated the nerve injury-induced increase in neurite outgrowth. Vasoactive intestinal polypeptide and neuropeptide Y had no influence on neurite outgrowth when applied to normal dissociated dorsal root ganglion cells, however, when added to cells co-cultured with spinal cord explants, both peptides significantly increased the percentage of cells with neurites. K252a, a protein kinase inhibitor, attenuated the trophic action of neuropeptide Y, but not that of vasoactive intestinal polypeptide. The action of vasoactive intestinal polypeptide on neurite outgrowth was attenuated by the protein kinase A inhibitor, the Rp-isomer of adenosine-3',5'-cyclic monophosphorothioate. The results suggest that the peptides may contribute, indirectly, to the nerve injury-induced increase in neurite outgrowth of sensory neurons via separate spinally-derived neurotrophic factors and the study provides further insight into the possible mechanisms underlying hyperalgesia associated with nerve injury.

Increased neurite outgrowth of cultured rat dorsal root ganglion cells following transection or inhibition of axonal transport of the sciatic nerve

Dissociated dorsal root ganglion cells (DRGs), taken from rats 2 weeks after sciatic nerve transection, have an increase in the percentage of cells with neurites compared to DRGs taken from normal animals. This study examines the possible factors that may contribute to the nerve injury-induced increase in neuritogenesis. Topical application of the local anaesthetic, bupivicaine, either to the nerve trunk prior to transection or to the proximal nerve stump for 2 weeks had no effect on the increased neurite outgrowth induced by nerve transection. Neurite outgrowth was also not influenced by administration of either nerve growth factor (NGF) via the femoral artery into normal rats or anti-NGF antiserum to the proximal nerve stump. Inhibition of axonal transport by topical application of vinblastine, however, induced a significant increase in neurite outgrowth compared to untreated controls. In addition, vinblastine-treated animals also develop hyperalgesia to mechanical stimulation and transganglionic labelling of sensory neurons with choleragenoid-horseradish peroxidase shows that the area of termination of myelinated sensory neurons in the spinal cord expands into lamina II. The results suggest that nerve injury-induced increase in neurite outgrowth is not dependent on NGF nor nerve impulses generated at the site of injury and supports the view that the absence of an inhibitory factor(s), that in normal animals may regulate neuronal outgrowth.

Evaluating a nebuliser service to improve patient care

This article describes the results of a postal questionnaire completed by 32 adults with home nebuliser equipment. The author found that patients had a limited understanding of the care and maintenance their equipment required. She puts forward a number of recommendations, including the provision of information for patients to control their problems.

Children with asthma in schools: an opportunity for "healthy alliances" between health and education authorities

Head teachers of all primary and secondary schools in County Durham were surveyed during 1994 to investigate school policy and management of children with asthma. Results indicate a need and opportunity to improve asthma care for children at school through healthy alliances between the health and education authorities.

Raised temperature reduces the incidence of diabetes in the NOD mouse

An association between the incidence of childhood Type 1 (insulin-dependent) diabetes mellitus and the average yearly temperature in different countries has been reported, the incidence being higher in countries with a lower mean temperature. We have studied the effect of environmental temperature on the incidence of diabetes in an animal model of Type 1 diabetes, the non-obese diabetic (NOD) mouse. Female NOD mice were divided at weaning, with one group placed at a higher temperature (mean 23.7 +/- 1.7 degrees C) and the other at a lower temperature (21.0 +/- 1.8 degrees C). At 20 weeks of age 6 of 16 mice at lower temperature and 1 of 17 mice at higher temperature had developed diabetes (p less than 0.02); at 30 weeks 10 of 16 and 5 of 17 mice had developed diabetes (p less than 0.05). Non-diabetic animals in the low temperature group had a higher food intake than those in the high temperature group between 13-15 weeks of age (28.0 +/- 1.2 g/week vs 24.8 +/- 0.7 g/week, p less than 0.05). In a parallel experiment, histological examination showed that there were similar degrees of insulitis in the high and low temperature groups at seven weeks of age. We conclude that environmental temperature can affect the incidence of diabetes in the NOD mouse and that this may be related to alterations in food intake.