Chronic low level physical activity as a determinant of high density lipoprotein cholesterol and subfractions

Physical activity has been associated with reduced risk of coronary heart disease. A mechanism for the reduced risk may be through increased high density lipoprotein cholesterol (HDL-C) and subfractions, in particular HDL2-C. Research associated with increased physical activity investigating HLD-C have assessed the effects of intense aerobic activity. The current research evaluated the relationship between low intensity, long duration activity to HDL-C and subfractions in 35 active postal carriers. Measurements of physical activity via the Large Scale Integrated monitor and reported miles walked, and lipoproteins were assessed at 3-month intervals over a 1-year period. Reported miles walked/day (5.3) was significantly correlated with HLD2-C (r = 0.50, P = 0.003) and approached significance for HDL-C (r = 0.29, P = 0.06). The Large Scale Integrated measures were correlated with HDL-C (r = 0.44, P = 0.008) and HDL2-C (r = 0.44, P = 0.007). Controlling for either age, alcohol consumption, body mass index, or leisure time activity did not reduce the relationship between reported miles walked or Large Scale Integrated readings and HDL2-C, suggesting that the increased HDL-C was the result of long duration, low intensity physical activity.     

Distribution and prevalence of Octomyomermis troglodytis (Nematoda: Mermithidae), a parasite of the western tree hole mosquito, Aedes sierrensis

Octomyomermis troglodytis was found infecting Aedes sierrensis larvae in 14.5% of 165 tree holes sampled between 1982 and 1986. Mermithid infections were detected in tree hole waters that ranged in pH from 6.5 to 9.3 and electrical conductivities between 0.10 and 5.11 mmhos/cm. Third and fourth instar larvae were most frequently infected, and most immatures that succumbed to infections died while in the fourth instar. Most hosts contained only one nematode. Infected adults were obtained from emergence traps over tree holes, from field-collected immatures reared in the laboratory, and from mosquito collections from sentinel humans. Octomyomermis troglodytis escaped from adults into water vials in the laboratory, suggesting that infected adult mosquitoes serve as dispersal agents for this parasite.     

Use of split-liver allografts does not impair pediatric recipient growth.

The use of split-liver (SL) allografts continues to be an excellent option for many pediatric recipients. Patient and graft survival with this graft type are comparable to patient and graft survival with whole organ grafts. Quality-of-life issues, specifically growth, for SL recipients have not been compared to those of recipients of more conventional whole-organ recipients. Pediatric recipients of SL and whole allografts at 2 institutions were identified. Height, z score, and delta z score were calculated for all recipients for each year after transplant. Between 1995 and 2004, 201 pediatric liver transplants were analyzed. Data were collected on 39 split-graft recipients and 36 whole-size recipients. Only subjects 3 years or younger were included in the study. Growth retardation was present in all recipients at transplant. Height z score post split and whole-size transplant were not statistically different at 1- (P = 0.65), 2- (P = 0.13), and 3-year (P = 0.32) anniversaries, respectively. Catch-up growth was present only in recipients of split grafts. In conclusion, the use of split grafts as opposed to whole-size grafts revealed no significant differences in terms of linear growth. Our report indicates that split-liver transplantation does not impair recipient growth.     

Electrophysiological correlates of presynaptic alpha 2-receptor-mediated inhibition of norepinephrine release at locus coeruleus synapses in dentate gyrus

Despite an abundance of evidence that presynaptic alpha 2-adrenergic receptors mediate inhibitory control of the release of norepinephrine (NE) from the terminals of locus coeruleus (LC) neurons, few studies have demonstrated the physiological significance of this "autoreceptor"-mediated inhibition on NE-mediated synaptic activity within the mammalian brain. This question was addressed by examining the effects of systemic administration of alpha 2-adrenergic agonists and antagonists on the ability of LC stimulation to augment the population spike recorded in the dentate gyrus in response to activation of the perforant path (PP). Extracellular field potentials were recorded in the cell body and dendritic layer of dentate gyrus following single shocks of the entorhinal cortex in halothane-anesthetized rats. Stimulation of the ipsilateral LC 35 msec prior to PP activation produced a short-term enhancement of the population spike amplitude recorded in the cell layer but did not significantly alter dendritic potentials. The effects of LC stimulation were blocked by administration of the beta-adrenergic antagonist propranolol but not the alpha 2-antagonist idazoxan and were abolished by pretreatment of animals with the catecholamine neurotoxin 6-hydroxydopamine. Administration of clonidine reversibly abolished the enhancement produced by LC conditioning. The effect of clonidine was dose dependent and was blocked by administration of idazoxan, which restored the LC potentiative effect. Conditioning stimulation of LC noradrenergic axons in the dorsal bundle also potentiated the PP-evoked population spike, and this effect was equally sensitive to the depressant action of clonidine. In comparison, clonidine, in the range of dosages tested, did not significantly affect the potentials evoked in the dendritic or cell layer by presentations of unconditioned PP test stimuli. We interpret these data to provide evidence for a functional impairment of LC-mediated physiological action on postsynaptic target cells as a result of presynaptic alpha 2-autoreceptor-mediated feedback inhibition of NE release.     

Toxicity but not arthritogenicity of Mycoplasma arthritidis for mice associates with the haplotype expressed at the major histocompatibility complex.

The use of inbred and congenic mouse strains established that toxicity and death induced by Mycoplasma arthritidis associates with the haplotype expressed at the murine major histocompatibility complex. Mice bearing H-2k and H-2d are susceptible, whereas those bearing H-2b are much more resistant. Mice susceptible to toxicity exhibited massive peritoneal adhesions and a decreased ability to clear organisms from the peripheral circulation. However, the severity of acute arthritis developing over a 3-month period was not statistically related to the haplotype expressed at the major histocompatibility complex. Lymphocyte activation in vitro by a soluble T-cell mitogen is also dependent on a similar haplotype expression.     

Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.      

Severe, late-onset graft-versus-host disease in a liver transplant recipient documented by chimerism analysis

A 52-year-old liver transplant recipient presented 8 months after transplantation with oral thrush, then 3 days later with oral ulcers and a diffuse rash, and 5 days later with an acutely reduced white blood cell count, rash, fever, and diarrhea. Bone marrow biopsy revealed severe aplasia. Although graft-versus-host disease (GVHD) was considered, the late onset of these symptoms was felt to render this etiology unlikely because GVHD usually occurs 2 to 6 weeks after transplantation. All potentially myelosuppressive medications were discontinued, and the patient was treated with high doses of hematopoietic growth factors. Because his symptoms continued, chimerism analysis was performed, which indicated that 96% of the peripheral blood mononuclear cells were of liver-donor origin. Ultimately, the patient underwent an allogeneic peripheral blood hematopoietic progenitor cell transplant from a human leukocyte antigen-identical brother, but he died 5 days after transplantation of overwhelming Candida kruseii infection. To our knowledge, this is the first chimerism-analysis-documented case of severe acute GVHD presenting so late after liver transplantation. It is of note that the patient had no known risks for GVHD in that he was relatively young and shared only one major human leukocyte antigen with his donor. Consideration should be given to GVHD as a cause of bone marrow aplasia at any time after organ transplantation. Storage of cell pellets from all transplant recipients and donors is highly recommended to facilitate the diagnostic evaluation.     

Oxidative killing of Aspergillus fumigatus proceeds by parallel myeloperoxidase-dependent and -independent pathways.

The relative importance of several oxygen intermediates in fungicidal action against opsonized Aspergillus fumigatus conidia was investigated with monocytes from normal volunteers and patients with either chronic granulomatous disease or myeloperoxidase (MPO) deficiency. Results from experiments in which catalase, taurine, mannitol, or glucose-glucose oxidase were added to these phagocytes indicated that the MPO-hydrogen peroxide-halide system and an MPO-independent oxidative system exerted comparable conidiacidal activity. These findings offer a plausible explanation for the susceptibility of patients with chronic granulomatous disease to invasive Aspergillus infections; their phagocytes fail to generate hydrogen peroxide, a substrate necessary for both systems. Patients with MPO deficiency are not known to be predisposed to invasive aspergillosis, suggesting that an MPO-independent oxidative system may provide an alternative mechanism for the oxidative killing of Aspergillus spp.