Spontaneous production of interleukin 3 by T lymphocytes from autoimmune MRL/MP-lpr/lpr mice

MRL/MP-lpr/lpr (MRL/lpr) mice develop a lupus-like autoimmune disease and a massive generalized lymphadenopathy associated with proliferation of nonmalignant Thy-1⁺ Lyt-1⁺ cells. The mechanism(s) leading to outgrowth of these cells is unknown. We report here that Thy-1⁺, Lyt-1⁺, Lyt-2^? lymphocytes from spleens of MRL/lpr mice, but not from several strains of normal mice, spontaneously secrete IL3. The presence of IL3 is shown by: (a) the ability of the supernatants from unstimulated spleen cells of MRL/lpr (MRL/lpr SUP) to support growth of IL3 but not IL2 addicted cells and (b) the growth-promoting activity in MRL/lpr SUP was absorbed with IL3-dependent cells but not with IL2-dependent cells. Spontaneous release of IL3 was detected in supernatants from spleen cells of 6-week-old MRL/lpr mice and the titers of IL3 activity increased with age. Nylon wool-enriched cells from spleens of MRL/lpr mice proliferated in response to purified IL3 and IL3 secreted by MRL/lpr T cells, in a manner similar to nylon wool-passed cells from normal mice. The cells responding to both sources of IL3 were Thy-1⁺, Lyt-1⁺, Lyt-2^?. Thus, Thy-1⁺, Lyt-1⁺,2^? cells from spleen of MRL/lpr mice spontaneously secrete IL3 and respond normally to this lymphokine. Four Thy-1⁺, Lyt-1⁺,2^? cell lines derived from unstimulated spleen cells of MRL/lpr mice were established in culture with IL3. These IL3-sensitive T cell lines help syngeneic and H-2-compatible normal small “resting” B cells to mature into plasma cells secreting predominantly IgG₁, IgG₂ and IgA. Taken together, these data and previous findings that T cells from MRL/lpr mice have an impaired production of and response to IL2, strongly suggest that abnormal production of IL3 may account for the outgrowth of Thy-1⁺, Lyt-1⁺,2^? cells in the MRL/lpr mouse. Finally, a mechanism linking abnormal production of IL3 and B cell hyperactivity in these animals is proposed.     

Activity of aphids associated with lettuce and broccoli in Spain and their efficiency as vectors of Lettuce mosaic virus

This research sought to identify the aphid virus vector species associated with lettuce and broccoli crops in Spain, and to determine their population dynamics and ability to transmit Lettuce mosaic virus (LMV). Green tile traps and Moericke yellow water-pan traps were used to monitor aphid flights during the spring and autumn growing seasons of 2001. Aphid species feeding on lettuce were counted weekly. The transmission efficiencies of LMV were determined for the aphid species caught most frequently. The Moericke traps generally caught more aphid species than the tile trap, but the latter was the most suitable to estimate flight activity of species involved in virus spread. Spring aphid catches indicated that the main aphid species landing on lettuce in the regions of Madrid and Murcia was Hyperomyzus lactucae, but Brachycaudus helichrysi was also abundant in both regions. In broccoli in the Navarra region, the most abundant species in spring were Aphis fabae, B. helichrysi and H. lactucae. In autumn-sown crops, the main species landing on lettuce in the Madrid region were Hyadaphis coriandri and Aphis spiraecola. In Murcia, A. spiraecola and Myzus persicae were the most abundant, while in Navarra, Therioaphis trifolii, and various Aphis spp. were the most numerous landing on broccoli. The main aphid species colonising lettuce was Nasonovia ribisnigri, but other less abundant colonising species were Aulacorthum solani and Macrosiphum euphorbiae. The most efficient vectors of LMV were M. persicae, Aphis gossypii and M. euphorbiae, while A. fabae and H. lactucae transmitted with low efficiency, and Rhopalosiphum padi and N. ribisnigri did not transmit. Occurrence of LMV epidemics in central Spain in relation to aphid flights and the role of weeds as virus reservoirs is discussed.     

Evidence for species differences in 'peripheral' benzodiazepine receptors: an autoradiographic study

The presence, density and distribution of 'peripheral' benzodiazepine (BZ)-binding sites was investigated by autoradiography in the brains of rats, mice, guinea pigs and cats and in some areas of the dog and monkey brains, using [3H]Ro 5-4864 as a ligand. Marked interspecies differences were found in the distribution and densities of these sites. Rats and mice presented a low density of binding uniformly distributed throughout the brain with high densities concentrated in the ependyma, choroid plexus and olfactory nerve layer of the olfactory bulb. In contrast, guinea pig and cat brains presented relatively high concentrations of peripheral BZ binding sites throughout the grey matter ependyma and choroid plexus, but low in the olfactory bulb. Monkey and dog brains presented low densities of peripheral BZ binding sites, including the choroid plexus.     

Autoradiographic localization of muscarinic cholinergic receptors in visual areas of cat brain: variations in sensitivity of N-[3H]methylscopolamine binding sites to carbachol and pirenzepine

The distribution of muscarinic acetylcholine receptors (MChRs) was studied in visual areas of cat brain using in vitro quantitative autoradiography with 1 nM N-[3H]methylscopolamine ([3H]NMS) as a radioligand. The highest density of [3H]NMS binding was observed in lamina A of the lateral geniculate nucleus (LGN) and in layer II/III of the visual cortex. The lowest binding was seen in the stratum griseum intermediale of the superior colliculus (SC). The comparison of inhibition of [3H]NMS binding by 100 microM carbachol and 300 nM pirenzepine showed that the SC and LGN contain predominantly M2 sites. M1 sites constitute the main population of MChRs in the cortical areas studied.     

Identification of 26 new constitutional RB1 gene mutations in Spanish, Colombian, and Cuban retinoblastoma patients

Constitutional mutations in the RB1 gene predispose to retinoblastoma development. Hence genetic screening of retinoblastoma patients and relatives is important for genetic counseling purposes. In addition, RB1 gene mutation studies may help decipher the molecular mechanisms leading to tumors with different degrees of penetrance or expressivity. In the course of genetically screening of 107 hereditary and non-hereditary retinoblastoma patients (11 familiar bilateral, 4 familiar unilateral, 49 sporadic bilateral and 43 sporadic unilateral) and kindred from Spain, Colombia and Cuba, using direct PCR sequencing, we observed 45 distinct mutations and four RB1 deletions in 53 patients (9 familiar bilateral, 2 familiar unilateral, 31 sporadic bilateral and 11 sporadic unilateral). Most of these mutations (26/45, 57%) have not been reported before. In 32 patients, the predisposing mutations correspond to nonsense (mainly CpG transitions) and small insertions or deletions whose expected outcome is a truncated Rb protein that lacks the functional pockets and tail. Five single aminoacid replacements and seventeen mutations affecting splicing sites were also observed in retinoblastoma patients. Two of these sixteen mutations are of unclear pathogenic nature.     

Die Kossa-Färbung als Hilfsmittel bei der histologischen Diagnose von Coxsackievirus-Erkrankungen in der Routineuntersuchung

Zusammenfassung Für die histologische Diagnostik der mit Coxsackievirus infizierten Mäuse stellt die Kossa-Färbung eine wesentliche Erleichterung dar, da sie bereits bei den kleinsten degenerativen Alterationen deutliche Reaktionen ergibt.     

Severe hypoxia decreases oxygen uptake relative to intensity during submaximal graded exercise

Summary The effect of severe acute hypoxia (fractional concentration of inspired oxygen equalled 0.104) was studied in nine male subjects performing an incremental exercise test. For power outputs over 125 W, all the subjects in a state of hypoxia showed a decrease in oxygen consumption ( O₂) relative to exercise intensity compared with normoxia (P < 0.05). This would suggest an increased anaerobic metabolism as an energy source during hypoxic exercise. During submaximal exercise, for a given O₂, higher blood lactate concentrations were found in hypoxia than in normoxia (P < 0.05). In consequence, the onset of blood lactate accumulation (OBLA) was shifted to a lower O₂ ( O₂ 1.77 l·min^–1 in hypoxia vs 3.10 l·min^–1 in normoxia). Lactate concentration increases relative to minute ventilation ( _E) responses were significantly higher during hypoxia than in normoxia (P < 0.05). At OBLA, _E during hypoxia was 25% lower than in the normoxic test. This study would suggest that in hypoxia subjects are able to use an increased anaerobic metabolism to maintain exercise performance.     

Diet Quality of Elite Australian Athletes Evaluated Using the Athlete Diet Index

While athletes’ nutrient intakes have been widely reported, few studies have assessed the diet quality of athletes. This is the first study to evaluate the diet quality of athletes using the purpose-built Athlete Diet Index (ADI). A convenience sample of 165 elite athletes from Australian sporting institutions completed the ADI online, with subsequent automated results provided to their respective accredited sports dietitians (ASDs). At the completion of athlete participation, ASDs (n = 12) responded to a range of survey items using a Likert scale (i.e., 1 = strongly agree to 5 = strongly disagree) to determine the suitability of the ADI in practice. Differences in ADI scores for demographics and sport-specific variables were investigated using independent t-tests, analysis of variance (ANOVA) and Bonferroni multiple comparisons. Spearman’s rank correlation was used to assess the association between total scores and demographics. The mean total ADI score was 91.4 ± 12.2 (range 53–117, out of a possible 125). While there was no difference in total scores based on demographics or sport-specific variables; team sport athletes scored higher than individual sport athletes (92.7 vs. 88.5, p < 0.05). Athletes training fewer hours (i.e., 0–11 h/week) scored higher on Dietary Habits sub-scores compared with athletes training more hours (≥12 h/week; p < 0.05), suggesting that athletes who train longer may be at risk of a compromised dietary pattern or less than optimal nutrition practices that support training. Most (75%) ASDs surveyed strongly agreed with the perceived utility of the ADI for screening athletes and identifying areas for nutrition support, confirming its suitability for use in practice.