Mechanism of slowing of mucociliary transport induced by SO2 exposure

Responses of nasal mucociliary transport mechanisms to exposure to 6 ppm SO₂ were studied in chickens in vivo. This model takes advantage of the natural cleft palate which exposes the mucociliated base of the nasal septum. Exposure to 6 ppm SO₂ decreased the mucociliary transport rate along the base of the nasal septum. The minimum force required to move an iron particle along this area of mucous membrane by use of a magnetic field in vivo increased significantly after SO₂ exposure, while the minimum force required to move an iron particle on a pool of mucus collected from the same chicken and tested in vitro showed no change after SO₂ exposure. The elastic recoil distance of mucus was measured both in vivo and in vitro. The in vivo recoil distance decreased significantly after SO₂ exposure, while SO₂ exposure did not change recoil distance in vitro. It is proposed that exposure of chickens to SO₂ results in the formation of multiple points of adhesion of strands of mucus between the acinar gland cells and the emergent extracellular mucus or adhesion of a mucous blanket to the cilia, causing mucociliary transport to be retarded or static.     

The reflex effect of changes in renal perfusion on hindlimb vascular resistance in anaesthetized rabbits

This study was designed to characterise the response of the hindlimb vasculature to reduced renal perfusion in the anaesthetized rabbit and to elucidate whether the stimulus was dependent upon reduced renal perfusion pressure (RPP) or blood flow (RBF). Acute decreases in renal perfusion resulted in rapid and reversible increases in femoral perfusion (FPP). This vascular response was completely abolished following renal denervation indicating that the afferent component of the reflex is neurally mediated. Acute hindlimb responses to changes in renal perfusion pressure were present whether the limb was perfused with homologous blood or cross-perfused with blood from a donor rabbit, demonstrating that the efferent component of the response is also neurally mediated. There was a 28-s latency for initiation of the hindlimb vasoconstriction, which is consistent with recent evidence for renal autocoid stimulation of the afferent renal nerve receptors. Decreasing RPP indirectly, by altering flow, resulted in a hindlimb vasoconstriction below approximately 55 mm Hg (7.3 kPa) RPP or 15 ml/ min RBF. However, decreasing RPP by directly reducing pressure in graded steps resulted in increases in FPP, which reflected the changes in renal flow; thus during the autoregulatory phase, where flow did not change as pressure fell, FPP also remained stable. The results of these protocols suggest that a neurally mediated hindlimb vascular reflex is stimulated by decreased renal flow rather than pressure.     

Retinoic acid is required for endodermal pouch morphogenesis and not for pharyngeal endoderm specification.

Because tissues from all three germ layers contribute to the pharyngeal arches, it is not surprising that all major signaling pathways are involved in their development. We focus on the role of retinoic acid (RA) signaling because it has been recognized for quite some time that alterations in this pathway lead to craniofacial malformations. Several studies exist that describe phenotypes observed upon RA perturbations in pharyngeal arch development; however, these studies did not address whether RA plays multiple roles at distinct time points during development. Here, we report the resulting phenotypes in the hindbrain, the neural crest-derived tissues, and the pharyngeal endoderm when RA synthesis is disrupted during zebrafish gastrulation and pharyngeal arch morphogenesis. Our results demonstrate that RA is required for the post-gastrulation morphogenesis and segmentation of endodermal pouches, and that loss of RA does not affect the length of the pharyngeal ectoderm or medial endoderm along the anterior-posterior axis. We also provide evidence that RA is not required for the specification of pharyngeal pouch endoderm and that the pharyngeal endoderm consists of at least two different cell populations, of which the pouch endoderm is sensitive to RA and the more medial pharyngeal endoderm is not. These results demonstrate that the developmental processes underlying pharyngeal arch defects differ depending on when RA signaling is disturbed during development.     

The droopy shoulder syndrome

We found that patients with thoracic outlet syndrome have: (1) low-set, "droopy" shoulders and long swan neck; (2) pain in the neck, shoulder, chest, arms, or hands; (3) aggravation of symptoms by downward traction and relief by propping up the arms; (4) occurrence in women; (5) absence of abnormal vascular, neurologic, and electrical findings; (6) a Tinel's sign over the brachial plexus; and (7) T-2 vertebra visible above the shoulders on lateral cervical spine films. In our experience, droopy shoulder syndrome has accounted for most cases of thoracic outlet syndrome but is largely unrecognized by physicians. Recognition of this syndrome should lead to a better understanding of the underlying pathophysiology and prevent unnecessary surgery.     

Interpretation of transference in the psychotherapy of adolescents and young adults

There is considerable controversy in the literature surrounding the role of interpretation of transference in the expressive psychotherapy of adolescents and young adults. The authors contend that interpretation of transference is often underutilized in the psychotherapy of adolescents and that many treatments could be enriched by its inclusion. It is argued that interpretation of the transference in the immediate "here and now" of the therapeutic encounter should take precedence over genetic transference interpretation, which attempts to link current attitudes toward the therapist to archaic attitudes toward the parents. Six guidelines founded on a developmental perspective are described for exploring transference themes in this age group. While interpretation of transference is neither a panacea nor uniquely mutative with adolescents and young adults, the authors believe it has an important role to play in expressive psychotherapy if used judiciously and with foresight.     

Effect of the tenure dentin bonding system on leakage of light-activated liners

This study investigated the effect of the Tenure dentin bonding system on the sealing properties of four light-activated liners. Dentinal slot preparations were made in extracted human molars and "restored" with Cavalite, TimeLine, VLC Dycal, and Zionomer liners. Samples were immersed in 0.05 percent crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned, and examined with an optical microscope. Our results indicated that the Tenure dentin bonding system reduced dye penetration around each of the light-activated liners tested. The Tenure/VLC Dycal system provided a more effective seal than the other liners.     

Assessment of changes in psychomotor performance of elderly subjects

1. The repeatability of a computerised psychomotor test battery on a day-to-day and week-to-week basis was assessed by determining its test-retest reliability and variations in group-means and intraindividual psychomotor performance scores of elderly people. 2. Psychomotor performance was assessed in 50 well-screened elderly subjects (21 males, 29 females; mean age 70.4 +/- 5.0 (s.d.) years) on 5 consecutive days and over 4 weeks in standardised test conditions. 3. The psychomotor test battery consisted of computerised versions of symbol digit substitution test (SDST), continuous attention test (CAT), choice reaction time (CRT), critical flicker fusion test (CFFT), cognitive flexibility test (FLEX), paired word association test (PWAT) and inspection time (INSP). 4. Main outcome measures were test-retest reliability, group variability and intraindividual variability. 5. There was no significant variation in group-means for all components of the test battery over 5 days or 4 weeks on two way analysis of variance. The intraindividual coefficient of variation was low for SDST, CRT, CFFT, FLEX, PWAT and INSP during the period of assessment. Test retest reliability was greater than 0.8 for SDST, CAT, CRT and PWAT. 6. Tests in the Automated Psychomotor Test Battery are reliable and repeatable measures of psychomotor performance on a day-to-day and week-to-week basis.     

Effect of d-amphetamine on prepulse inhibition of the startle reflex in humans

Rationale: Prepulse inhibition of the startle reflex (PPI) is attenuated in animals after administration of d-amphetamine and other drugs that stimulate mesolimbic dopamine activity. Objective: The aim of the present study was to evaluate the effects of d-amphetamine (20 mg) on a variety of psychophysiological and subjective measures, including PPI, in humans. Method: Thirty-six participants (18 women) participated in a double-blind, placebo controlled, repeated measures study. In one session, participants received d-amphetamine (20 mg) orally, and in the other session, participants received an identical appearing placebo. Participants were assessed at 60, 90, and 120 min after ingestion with a 5-min block of startle trials (six control trials and six prepulse trials) followed by subjective measures of stimulation and mood. Results: d-Amphetamine increased subjective measures of stimulation and euphoria, attenuated PPI, and increased heart rate, relative to placebo treatment. Conclusions: The effect of d-amphetamine on the subjective measures was substantial and consistent over time, while the effect on PPI was only observed at 90 min after ingestion, and the effect on heart rate was limited to 90 and 120 min after ingestion. Received: 22 June 1998/Final version: 23 November 1998     

The characterization of biological features in dedifferentiated liposarcomas by means of principal components and discriminant analyses of 25 computer-generated variables from Feulgen-stained nuclei and histological slides

Several groups of lipomatous tumors are not yet clearly characterized on the biological level. In order to attempt to classify the dedifferentiated liposarcomas with respect to other types of malignant liposarcomas, 80 adipose tumors were submitted to the combination of two computer-assisted methodologies. These two methodologies consisted of i) the determination of 25 variables, and ii) the analysis of the diagnostic information contributed by these 25 variables by means of two complementary techniques, i.e. principal components and discriminant analyses. The 25 variables were computed by means of image cytometry on Feulgen-stained nuclei and histological slides, quantitatively describing distinct biological characteristics relating to morphonuclear (chromatin pattern) features (14 variables), nuclear DNA content distribution (9 variables), and tissue architecture pattern (2 variables). The 80 adipose tumors included 21 typical lipomas, 7 atypical lipomas (defined as extremity adipose tumors with a histopathological pattern of well-differentiated liposarcomas), 16 retroperitoneal and 5 non-retroperitoneal abdominal well-differentiated liposarcomas, 9 dedifferentiated liposarcomas, 8 myxoid (intermediate-grade tumor) and 14 pleomorphic (high-grade tumor) liposarcomas. The data strongly suggest that the dedifferentiated liposarcomas exhibit biological characteristics which are distinct from those of low- and high-grade liposarcomas, but similar to those of intermediate ones. The results also show that typical and atypical lipomas are two distinct biological entities. In contrast, the atypical lipomas and the well-differentiated retroperitoneal and non-retroperitoneal liposarcomas exhibited a high number of similar biological characteristics. Computer-assisted methods contribute valuable information to characterize lipomatous tumor biology.