Nitrogen mustard up-regulates Bcl-2 and GSH and increases NTP and PCr in HT-29 colon cancer cells

We hypothesized that unexplained increases in nucleoside triphosphates (NTP) observed by 31P magnetic resonance spectroscopy (MRS) after treatment of tumours by DNA-damaging agents were related to chemotherapy-induced up-regulation of the bcl-2 gene and DNA damage prevention and repair processes. To test this hypothesis, we treated HT-29 cells with 10(-4) M nitrogen mustard (HN2) and performed sequential perchloric acid extractions in replicate over 0-18 h. By reference to an internal standard (methylene diphosphonic acid), absolute changes in 31P-detectable high-energy phosphates in these extracts were determined and correlated with changes in bcl-2 protein levels, cell viability, cell cycle, apoptosis and total cellular glutathione (GSH) (an important defence against DNA damage from alkylating agents). After HN2 administration, bcl-2 protein levels in the HT-29 cell line rose at 2 h. Cell viability declined to 25% within 18 h, but apoptosis measured using fluorescence techniques remained in the 1-4% range. Increased cell division was noted at 4 h. Two high-energy interconvertible phosphates, NTP (P < or = 0.006) and phosphocreatine (PCr) (P < or = 0.0002), increased at 2 h concurrently with increased levels of bcl-2 protein and glutathione. This study demonstrates that bcl-2 and glutathione are up-regulated by HN2 and links this to a previously unexplained 31P MRS phenomenon: increased NTP after chemotherapy.     

An examination of the distinction between nouns and verbs: associations with two different kinds of motion

Four experiments provide evidence that people are biased to associate particular types of motion with nouns and different types of motion with verbs. Novel nouns and verbs were related to two types of motion: (1) path, or the direction of motion of one character with respect to the other character, and (2) movement orientation, or the direction a character was facing as it moved. Subjects associated verbs more strongly with path than with movement orientation. In contrast, they associated nouns more strongly with movement orientation than with path. Movement orientation was associated with both object categories and verbs, inconsistent with a complete division of labor between these two types of categories. These results are consistent, however, with the notion that people are biased to associate verbs with relations between objects, whereas they are biased to associate object categories with motions defined with respect to the object carrying out those motions.     

Identification of a new splice form of the EDA1 gene permits detection of nearly all X-linked hypohidrotic ectodermal dysplasia mutations

X-linked hypohidrotic ectodermal dysplasia (XLHED), the most common of the ectodermal dysplasias, results in the abnormal development of teeth, hair, and eccrine sweat glands. The gene responsible for this disorder, EDA1, was identified by isolation of a single cDNA that was predicted to encode a 135-amino-acid protein. Mutations in this splice form were detected in <10% of families with XLHED. The subsequent cloning of the murine homologue of the EDA1 gene (Tabby [Ta]) allowed us to identify a second putative isoform of the EDA1 protein (isoform II) in humans. This EDA1 cDNA is predicted to encode a 391-residue protein, of which 256 amino acids are encoded by the new exons. The putative protein is 94% identical to the Ta protein and includes a collagen-like domain with 19 repeats of a Gly-X-Y motif in the presumptive extracellular domain. The genomic structure of the EDA1 gene was established, and the complete sequence of the seven new exons was determined in 18 XLHED-affected males. Putative mutations, including 12 missense, one nonsense, and four deletion mutations, were identified in approximately 95% of the families. The results suggest that EDA1 isoform II plays a critical role in tooth, hair, and sweat gland morphogenesis, whereas the biological significance of isoform I remains unclear. Identification of mutations in nearly all of the XLHED families studied suggests that direct molecular diagnosis of the disorder is feasible. Direct diagnosis will allow carrier detection in families with a single affected male and will assist in distinguishing XLHED from the rarer, clinically indistinguishable, autosomal recessive form of the disorder.     

Augmented expression of glomerular basement membrane specific type IV collagen isoforms (alpha3-alpha5) in experimental membranous nephropathy

The swelling, erosion and solvent front penetration properties of mini-matrices containing xanthan (X), locust bean (LB) and karaya (K) gums were examined, analysed and related to the overall in vitro release kinetics of diclofenac sodium, used as a model drug. Mini-matrices were produced with drug:gum ratios of 1:1 as well as formulations of drug and X in combinations of 2:1, 2:3 and 1:2. The rank order of decreasing swelling index (SI) in both axial and radial dimensions was X?K?LB and each gum showed almost Fickian swelling behaviour. The solvent front penetration rates were consistent with the rates of swelling. However, the order of decreasing drug release and erosion rates was LB>X>K and all formulations demonstrated anomalous (non-Fickian) drug release kinetics. Therefore Fickian drug diffusion and polymer erosion were both occurring simultaneously. The dominant mechanism depended on the nature and content of the gum, as well as the stage in the dissolution time period. There was a loss of matrix integrity in formulations containing a high drug:gum ratio.     

The chemorepulsive activity of the axonal guidance signal semaphorin D requires dimerization

The axonal guidance signal semaphorin D is a member of a large family of proteins characterized by the presence of a highly conserved semaphorin domain of about 500 amino acids. The vertebrate semaphorins can be divided into four different classes that contain both secreted and membrane-bound proteins. Here we show that class III (SemD) and class IV semaphorins (SemB) form homodimers linked by intermolecular disulfide bridges. In addition to the 95-kDa form of SemD (SemD(95k)), proteolytic processing of SemD creates a 65-kDa isoform (SemD(65k)) that lacks the 33-kDa carboxyl-terminal domain. Although SemD(95k) formed dimers, the removal of the carboxyl-terminal domain resulted in the dissociation of SemD homodimers to monomeric SemD(65k). Mutation of cysteine 723, one of four conserved cysteine residues in the 33-kDa fragment, revealed its requirement both for the dimerization of SemD and its chemorepulsive activity. We suggest that dimerization is a general feature of sema- phorins which depends on class-specific sequences and is important for their function.     

Dual origins of Finns revealed by Y chromosome haplotype variation

The objective of this study was to determine effects of photoperiod and age on the circulating concentrations of LH, testosterone (T), thyroxine (T4), and semen production in male turkeys. Male turkeys from 10 or 12 wk of age were maintained under either a long-day (LD) photoperiod of 16L:8D up to 35 wk (LL), or a short-day (SD) photoperiod of 6L:18D to 29 wk and then an LD photoperiod of 16L:8D up to 35 wk of age (SL). Plasma concentrations of both LH and T increased by 17 or 18 wk of age under both photoperiods, but higher levels were attained in the LL group prior to 29 wk of age. Both LH and T levels increased significantly within days in the SL group after the group was switched to LD at 29 wk of age. Higher levels of T4 were present in the LL group prior to sexual maturation. No differences were observed in T4 concentration between lighting treatments after sexual maturation. The LL group first produced semen at 20-22 wk of age, which was about 1 wk earlier than first semen production in the SL group. A significantly larger volume of semen was produced in the LL group at most ages. No further increase in semen production was observed in the first 6 wk after the SL group was switched to the LD photoperiod at 29 wk of age. Pulsatile patterns of LH and T were characterized by serial blood sampling at 13, 23, and 35 wk of age under both the LL and SL photoperiods. The baseline levels of both LH and T in male turkeys were influenced by age and photoperiod. However, pulse characteristics (numbers, duration, and amplitude) of LH did not change with age or lighting treatment, while pulse characteristics of T did change with age. We conclude that exposing male turkeys to an LD photoperiod from 10 or 12 wk of age advanced the age of sexual maturation and induced earlier increased concentrations of LH and T.     

Effects of postural change on aspiration in head and neck surgical patients

This study was designed to define the effects of postural change on liquid aspiration during videofluorographic examination of oropharyngeal swallow in head and neck surgical patients. Thirty-two patients were given two swallows of five different amounts of liquid barium as tolerated. When aspiration occurred, the patient's head and/or body position was changed, new posture being determined by the swallowing disorder identified as the cause of the aspiration. Postural techniques were successful in eliminating aspiration on at least one volume of liquid in 81% of these patients. Patients in all surgical groups were able to use postures with equal success. A variety of positions were used in each type of surgical patient, indicating that these patients exhibited a variety of swallowing problems. Results emphasize the importance of introducing postural techniques during the radiographic study of oropharyngeal swallow to facilitate safe oral intake of liquids.