The effect of noradrenaline on the end-plate potential in twitch fibres of the frog

1. The action of noradrenaline in increasing the amplitude of the end-plate potential (e.p.p.) has been studied in magnesium-blocked frog skeletal muscle.2. Noradrenaline (10(-5)M) increased the e.p.p. by about 20% without causing any comparable change in the amplitude of the miniature end-plate potentials (m.e.p.p.s). It was concluded that noradrenaline acts by potentiating the release of acetylcholine by the nerve impulse, rather than by increasing the sensitivity of the end-plate.3. In support of this, it was found that the increase in e.p.p. amplitude was associated with a reduction in the variability of successive e.p.p.s, as is to be expected if the quantal content of the e.p.p. became larger. Further, noradrenaline was without effect on the response to iontophoretically-applied acetylcholine, although it potentiated depolarizations elicited by acetylcholine applied for much longer periods in the bathing fluid.4. Noradrenaline increased the frequency of occurrence of m.e.p.p.s, and unusually large m.e.p.p.s. were occasionally observed.     

Angiogenic response induced by acellular aortic matrix in vivo

In this study, we investigated the angiogenic response induced by acellular aortic matrices implanted in vivo onto the chick embryo chorioallantoic membrane (CAM), a useful model for such investigation. Results showed that acellular matrices were able to induce a strong angiogenic response comparable to that of fibroblast growth factor 2 (FGF-2), a well-known angiogenic cytokine. The angiogenic response was further increased when exogenous FGF-2 or transforming growth factor beta 1 (TGF-beta1) were added to the matrices and inhibited by the addition of an anti-FGF-2 or anti-TGF-beta1 antibodies. The response may be considered dependent on a direct angiogenic effect exerted by the matrices and in part also by the presence of FGF-2 and TGF-beta1 in the acellular matrices.     

Extraskeletal Osteosarcoma with Unusual Ultrastructural Features

A case of extraskeletal osteosarcoma was observed in the thigh of a 33-year-old male patient. Ultrastructurally the tumor was characterized by the presence of a particular dense type of cell, the nucleus of which showed a characteristic combination of features: large amounts of condensed mar-ginated chromatin, prominent perichromatin granules, vermicellar bodies, and undulating microtubules. The tumor also contained intermediate-type cells with a more typical osteoblastic appearance, and more blastic cells. All three cell types contained varying amounts of dilated rough endoplasmic reticulum with prominent inclusions of crystalline material showing a hexagonal or banded pattern, indicating that the cells represent different stages of maturation rather than genuinely different types of cells. Dense cells showing the same characteristic combination of nuclear features have been described once before in a case of parosteal osteosarcoma. Our results indicate that these cells are a particular form of osteogenic cell. The presence of undulating microtubules and vermicellar bodies suggest a possible association with the presence of virus and/or increased levels of interferon.     

Estimation of genetic risk for type 1 diabetes

The most important gene loci defining risk of type 1 diabetes mellitus (T1DM) are located within the HLA gene region. HLA-DQ molecules are of primary importance but HLA-DR gene products modify the risk conferred by HLA-DQ. The risk associated with an HLA genotype is defined by the particular combination of susceptible and protective alleles. The highest risk is associated with a combination of two different risk haplotypes (7% risk to develop T1DM in Finland) whereas protective genotypes covering 69% of population have a risk of less than 0.2%). The complicated analysis of HLA genotypes is simplified by strong linkage disequilibrium between HLA-DRB1, -DQA1 and -DQB1 loci. In many cases one can deduce the alleles of other loci based on determination of the alleles in one locus. Differences between various populations in the frequency of marker alleles and in the linkages between them has to be taken into account. We have developed PCR based typing methods that utilize blood spot samples, microtiter plate format and lanthanide labeled oligonucleotide probes to define HLA-DQ and -DR alleles relevant for T1DM risk. Typing is run stepwise so that after initial HLA-DQB1 typing only those samples will be further analyzed in which -DQA1 or -DRB1 typing is informative and expected to contribute to the risk estimation. This method has been used to screen more than 50,000 newborn infants in Finland over a time period of 6 years, and it has been able to identify most children who have developed T1D during the follow-up period. The efficiency of the procedure has also been tested in Finnish and Greek populations.     

Immunohistochemical localization of nNOS in the skin and nerve fibers of the earthworm Lumbricus terrestris L. (Annelida Oligochaeta)

The epidermis of the earthworm Lumbricus terrestris is a multifunctional tissue. It is composed of supporting, mucous, neuroendocrine-like, sensory and basal cells. NO is considered to be a molecule that regulates numerous functional activities (also in non-neuronal cells) in vertebrates. In the earthworm epidermis, we found neuronal NO synthase immunopositivity in orthochromatic and metachromatic mucous cells, neuroendocrine-like cells and in epidermal and subepidermal nerve fibers and striated muscle fibers. It is suggested that NO has a multitude of biological actions, affecting functional activities of the epidermis such as tissue homeostasis, control of secretion, proliferation, respiration, defense, water-salt balance, as well as regulation of tonus in vascular and striated muscles.     

Classical Noonan syndrome is not associated with deletions of 22q11

Deletions of 22qll cause DiGeorge sequence (DGS), velo-cardio-facial syndrome (VCFS), conotruncal anomaly face syndrome, and some isolated conotruncal heart anomalies. Demonstration of a 22qll deletion in a patient with manifestations of DGS and Noonan syndrome (NS) has raised the question of whether NS is another of the chromosome 22 microdeletion syndromes. This prompted us to evaluate a cohort of patients with NS for evidence of 22qll deletions. Five of 6 NS propositi studied in our laboratory with marker N25 (D22S75) did not have a 22qll deletion. A 2-month-old infant with several findings suggestive of NS did have a 22qll deletion, suggesting that a small number of 22qll deletion propositi may present with a NS-like picture. However, most cases of NS must have another cause. © 1995 Wiley-Liss, Inc.     

Infant gaze, head, face and self-touch at 4 months differentiate secure vs. avoidant attachment at 1 year: a microanalytic approach

The study attempted to distinguish avoidant vs. secure infants at 1 year from 4-month infant behavior only, during a face-to-face play interaction with the mother. Thirty-five 4-month-old infants were coded second by second for infant gaze, head orientation, facial expression and self-touch/mouthing behavior. Mother behavior was not coded. At 1 year, 27 of these infants were classified as secure (B), and 8 as avoidant (A) attachment in the Ainsworth Strange Situation. Compared with the B infant, the future A infant spent less time paying 'focused' visual attention (a look of a minimum 2 seconds duration) to the mother's face. Only if the A infant engaged in self-touch/mouthing behavior did its focused visual attention match that of the B. Markovian t to t+1 transition matrices then showed that both for future A and for future B infants, focused visual attention on the mother constrained the movements of the head to within 60 degrees from center vis-à-vis, defining head/gaze co-ordination within an attentional-interpersonal space. However, infant maintenance of head/gaze co-ordination was associated with self-touch/mouthing behavior for the A infant but not the B. Positive affect was associated with a disruption of head/gaze co-ordination for the A but not the B. Whereas the B had more variable facial behavior, potentially providing more facial signaling for the mother, the A had more variable tactile/mouthing behavior, changing patterns of self-soothing more often. Thus, infants classified as A vs. B at 12 months showed different behavioral patterns in face-to-face play with their mothers as early as 4 months.     

Interleukin-7-engineered mesenchymal cells: in vitro effects on naive T-cell population.

T-cell homeostasis is regulated by several molecules; among these, interleukin (IL)-7 plays an essential role in the survival and homeostatic proliferation of peripheral naive T cells. In a previous study, we investigated whether human mesenchymal stromal cells (MSCs) could be engineered with the IL-7 gene to produce functional level of this cytokine. In the present study, we analyzed the impact of different quantities of IL-7 produced by MSCs on the survival and proliferation of a negative immunoselected naive (CD3(+)/CD45RA(+)) T-cell population. Co-cultivation of peripheral naive T cells with MSCs producing low (16 pg/mL) or high (1000 pg/mL) IL-7 levels or in the presence of exogenous IL-7 (0.01 ng/mL and 100 ng/mL) maintained the CD3(+)/CD45RA(+) naive T-cell phenotype. Chemokine receptor CCR7(+) expression was also maintained among this T-cell population. Naive T-cell molecular characteristics were maintained as assessed by the Vbeta spectratyping complexity score, which showed the maintenance of a broad T-cell repertoire. No Th1 or Th2 differentiation was observed, as assessed by interferon-gamma or IL-4 accumulation. In contrast, only MSCs producing high amounts of IL-7 caused increased activation (CD25 31.2% +/- 12% vs 10% +/- 3.5%; P < .05), proliferation (CD71 17.8+/-7% vs 9.3%+/-3, P < .05), apoptosis (assessed by annexin V: 18.6% +/- 5% vs 14.9% +/- 2.6%; P > .05), and the phase S cell cycle (15% vs 6.9%, P > .05). Exogenous IL-7 exhibited no significant effect. In conclusion, we demonstrated that IL-7 produced by MSCs has a dose-independent effect on naive T-cell survival while exerting a dose-dependent effect on activation/proliferation. Due to the continuous production of IL-7 by engineered cells, our system is more efficacious than exogenous IL-7.     

Fryns syndrome without diaphragmatic hernia?

We report on a child with Fryns syndrome including lung hypoplasia, characteristic facial appearance, cleft palate, cardiac anomaly, distal limb abnormalities, absent nipples, bicornuate uterus and early death. In contrast to most patients with Fryns syndrome, diaphragmatic hernia was absent in our patient. However, the diaphragm was reduced to a fibrous web with reduced muscular component.     

Limb-body wall complex: 4 new cases illustrating the importance of examining placenta and umbilical cord

Limb-body wall complex (LBWC) is a rare, sporadic, congenital defect defined as a combination of at least two of three characteristics: 1. limb defects, 2. anterior body wall defects, and 3. exencephaly or encephalocoele with/without facial clefts. Three pathogenic mechanisms have been proposed: early amnion rupture, vascular disruption and embryonic dysgenesis. In this study we carried out the pathological evaluation of four fetuses with LBWC and their placentas. None of the cases had craniofacial defects. Three fetuses showed an abdominal wall defect with eventration of abdominal organs, cloacal exstrophy, absent external genitalia, abnormal internal genitalia, scoliosis and lower limb defects. One fetus showed failure of closure of both thoracic and abdominal walls with ectopia cordis, evisceration of left lung and abdominal organs, severe reduction defect of left arm, but normal colon, anus, bladder, genitalia and lower limbs. All cases had a short, malformed umbilical cord, incompletely covered by amnion. The umbilical vessels were embedded in an amniotic sheet which connected the skin margin of the anterior body wall defect to the placenta. These anomalies suggest an abnormal body stalk development as a pathogenic mechanism for LBWC. Prenatally, the abnormal fetoplacental attachment can be detected ultrasonographically by the end of the first gestational trimester. Postnatally, the examination of placenta, umbilical cord and membranes is crucial in confirming the diagnosis of LBWC.