Altered renal immune complexes deposition in female BWF1 lupus mice following Plasmodium chabaudi infection

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease that has a mysterious relationship with malaria infection. The current study was designated to compare between the effect of the live and the gamma irradiated Plasmodium chabaudi infection on BWF1 lupus murine model. A total of 30 female BWF1 mice were randomly divided into three groups (10 mice/group) as follows: group (I) lupus group (lupus non infected); group (II) live malaria infected group (lupus + live malaria infection); and group (III) irradiated malaria-infected group (lupus + gamma irradiated malaria infection). Live P. chabaudi infection was accompanied with a decrease in survival rate and food consumption in comparison to the control group of mice while gamma irradiated P. chabaudi -infection was unable to do this effect. Additionally, live P. chabaudi infection was accompanied with an increased level of proteinuria and increased rate of immune complexes deposition in kidney. Moreover, infection with live, but not gamma-irradiated P. chabaudi was accompanied with an increase in nitric oxide (NO), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) levels in plasma of lupus mice. The levels of both total cholesterol and triglycerides in plasma of lupus mice after live P. chabaudi infection were obviously decreased in comparison to the control group. On the other hand, gamma-irradiated P. chabaudi infection resembled the control group. Our data revealed that infection of lupus mice with live but not gamma-irradiated P. chabaudi has several histological and biochemical effects.     

Speciation and Species Separation in Hordeum L. (Poaceae) Resolved by Discontinuous Molecular Markers1

Abstract: Amplified fragment length polymorphisms (AFLPs) were used to evaluate the capacity of discontinuous markers to reveal genetic structure within Hordeum , a challenging higher plant genus from the standpoint of natural systematics. Phylogenies of 63 accessions encompassing nine species from four Hordeum sections were inferred from polymorphisms scored at 600 loci. Phylogenies based on sequences from the nuclear internal transcribed spacer (ITS) region were constructed for comparison, but revealed severe sampling errors inherent to single genes. Although superior by virtue of providing genome-wide estimates of genetic similarity, the adoption of AFLPs in infrageneric studies requires caution. Comigrating AFLP bands studied here could be divided on the basis of band intensity variation into two types that are □ 100 % identical and < 40 % identical in DNA sequence, respectively, in infrageneric comparisons. Thus, the careful selection of AFLP bands to be analyzed bears heavily upon their phylogenetic utility. Within the H. murinum complex, which encompasses three morphologically distinct subspecies, AFLP data from 37 accessions reveal unexpected genetic differentiation between H. murinum, glaucum populations to the east and west of Alexandria (Egypt), suggesting the presence of allopatric speciation in the wake of human settlement.     

Effects of NREM sleep on dynamic within-breath changes in upper airway patency in humans

Morrell, M. J., and M. S. Badr. Effects of NREM sleepon dynamic within-breath changes in upper airway patency in humans. J. Appl. Physiol. 84(1): 190-199, 1998.The purpose of our study was to compare inspiratory- andexpiratory-related changes in retropalatal cross-sectional area (CSA)during wakefulness to those during non-rapid-eye-movement (NREM) sleep.We studied 18 subjects in whom the severity of sleep-disorderedbreathing varied. Relative changes in CSA were visualized by usingfiber-optic endoscopy. For each breath analyzed (wakefulnessn = 4-13; sleepn = 7-16), the CSA was measuredat fixed points within inspiration and expiration (0, 25, 50, and 100%of the inspiratory and expiratory duration); these measurements wereexpressed as a percentage of the CSA that occurred at the start ofinspiration. During wakefulness, there was a statistically significantincrease in the retropalatal CSA (compared with the start ofinspiration) only during early expiration (group mean: expiration, 0% = 112.6 ± 3.2 (SE) %; 25% = 122.8 ± 6.2%; 50% = 110.6 ± 3.8%). In contrast, during sleep, significant changes in CSA occurredduring both inspiration and expiration (group mean: inspiration, 25% = 75.3 ± 6.0%; 50% = 66.7 ± 7.7%; 75% = 64.6 ± 8.1%;expiration, 0% = 126.8 ± 11.8%; 25% = 125.3 ± 6.9%). Theexpiratory-related increase in CSA was followed by narrowing such thatat end expiration the caliber of the airway was returned to thatoccurring at the beginning of inspiration (group mean at end expiration = 98.6 ± 3.1%). The largest changes in CSA occurred in thesubjects with an increased body mass index (BMI). We conclude that,during NREM sleep, significant changes in CSA occur during bothinspiration and expiration and that the magnitude of these changes issignificantly influenced by BMI.

     

Selective inhibition of hepatic peroxisomal fatty acid beta-oxidation by enoximone.

Although beta-oxidation of fatty acids occurs in both peroxisomes and mitochondria, beta-oxidizing enzymes in these organelles have distinct differences in their specifity and sensitivity to inhibitors. In this study, the effects of the phosphodiesterase inhibitor enoximone on hepatic peroxisomal and mitochondrial beta-oxidation were investigated. In liver homogenates from control rats, cyanide-insensitive peroxisomal beta-oxidation of palmitoyl-CoA was inhibited progressively by increasing concentrations of enoximone. Similar results were obtained in liver homogenates from rats pretreated with the known peroxisomal proliferator diethylhexylphthalate. In contrast, mitochondrial beta-oxidation of palmitoyl-CoA was not inhibited by enoximone. These data show that enoximone selectively inhibits basal as well as induced peroxisomal, but not mitochondrial, beta-oxidation of the CoA thioester of long-chain fatty acids. The availability of specific inhibitors of peroxisomal beta-oxidation should prove useful in elucidating regulatory mechanisms operative in this pathway in normal as well as in proliferated peroxisomes.     

Molecular cloning and functional expression of rat leukotriene A4 hydrolase using the polymerase chain reaction.

We isolated a cDNA encoding rat leukotriene A4 (LTA4) hydrolase from mesangial cells by the polymerase chain reaction according to the human amino acid sequence. The deduced amino acid sequence shows that rat LTA4 hydrolase is a 609 amino acid protein with an Mr 69 kDa. Comparison of human LTA4 hydrolase revealed 93% homology, and include zinc-binding motifs of aminopeptidases. COS-7 cells transfected with the cDNA revealed substantial LTA4 hydrolase activity, and their activities were abolished by preincubation with captopril, representing the first reported cDNA expression of recombinant enzyme in mammalian cells. RNA blot analysis indicated that LTA4 hydrolase was expressed in glomerular endothelial, epithelial and mesangial cells.     

Daily variations in colchicine-induced apoptosis in duodenal crypts

Apoptotic cell death can be induced by several agents, among them colchicine, a microtubule disrupting-drug that affects continuously renewing cell populations, such as the intestinal crypt enterocytes. The objectives of this investigation were (1) to confirm in vivo colchicines-inductive effect and (2) to determine the existence of 24 h variations in the crypt enterocytes apoptotic indices. The study was done on C3H/S male adult mice housed under standardized conditions. Starting at midnight until the end of a circadian period, subgroups of mice were sacrificed after having been injected with colchicine or saline i.p. 4h beforehand. Duodenal samples were processed for hematoxylin-eosin staining and TUNEL technique. In order to score the number of apoptosis, the longitudinal sections of the crypts were divided into three regions comprised, respectively, of tiers 1-4, 5-12, and 13-20, proceeding from the bottom to the top of the crypt. Values of each lot were expressed as mean +/- SEM. A highly significant statistical difference in apoptotic indices was found for colchicine-treated animals. The 24 h curve for colchicine-induced apoptosis displayed qualitative and quantitative differences compared to other inducer agents. Highest apoptotic indices were found in the deepest crypt regions. Daily variations were observed in all the crypt sectors of the colchicine-treated animals and in tiers 5-12 of the saline controls. The present work demonstrates that the colchicine cytotoxicity due to its apoptotic-inducing effect depends on the dosing time during the 24 h in this mouse strain.     

Preliminary evaluation of non-native rainbow trout (Oncorhynchus mykiss) impact on the Cederberg ghost frog (Heleophryne depressa) in South Africa’s Cape Fold Ecoregion

We evaluated the impact of non-native rainbow trout Oncorhynchus mykiss on a population of endemic Cedarberg ghost frog Heleophryne depressa in the upper Krom River (Olifants-Doring River Catchment, Cape Fold Ecoregion). We compared H. depressa abundance (using kick-sampling and underwater video analysis) and environmental conditions between sites above and below a waterfall that marks the upper distribution limit of O. mykiss. Heleophryne depressa abundance was significantly greater above the waterfall than that below it, and, because there was no significant difference in measured environmental variables, O. mykiss presence is identified as the most likely explanation for the observed decrease in H. depressa abundance.     

Long-term facilitation in obstructive sleep apnea patients during NREM sleep.

Repetitive hypoxia followed by persistently increased ventilatory motor output is referred to as long-term facilitation (LTF). LTF is activated during sleep after repetitive hypoxia in snorers. We hypothesized that LTF is activated in obstructive sleep apnea (OSA) patients. Eleven subjects with OSA (apnea/hypopnea index = 43.6 +/- 18.7/h) were included. Every subject had a baseline polysomnographic study on the appropriate continuous positive airway pressure (CPAP). CPAP was retitrated to eliminate apnea/hypopnea but to maintain inspiratory flow limitation (sham night). Each subject was studied on 2 separate nights. These two studies are separated by 1 mo of optimal nasal CPAP treatment for a minimum of 4-6 h/night. The device was capable of covert pressure monitoring. During night 1 (N1), study subjects used nasal CPAP at suboptimal pressure to have significant air flow limitation (>60% breaths) without apneas/hypopneas. After stable sleep was reached, we induced brief isocapnic hypoxia [inspired O(2) fraction (FI(O(2))) = 8%] (3 min) followed by 5 min of room air. This sequence was repeated 10 times. Measurements were obtained during control, hypoxia, and at 5, 20, and 40 min of recovery for ventilation, timing (n = 11), and supraglottic pressure (n = 6). Upper airway resistance (Rua) was calculated at peak inspiratory flow. During the recovery period, there was no change in minute ventilation (99 +/- 8% of control), despite decreased Rua to 58 +/- 24% of control (P < 0.05). There was a reduction in the ratio of inspiratory time to total time for a breath (duty cycle) (0.5 to 0.45, P < 0.05) but no effect on inspiratory time. During night 2 (N2), the protocol of N1 was repeated. N2 revealed no changes compared with N1 during the recovery period. In conclusion, 1) reduced Rua in the recovery period indicates LTF of upper airway dilators; 2) lack of hyperpnea in the recovery period suggests that thoracic pump muscles do not demonstrate LTF; 3) we speculate that LTF may temporarily stabilize respiration in OSA patients after repeated apneas/hypopneas; and 4) nasal CPAP did not alter the ability of OSA patients to elicit LTF at the thoracic pump muscle.