Inhibition of pig aortic smooth muscle cell DNA synthesis by selective type III and type IV cyclic AMP phosphodiesterase inhibitors.

Foetal calf serum (FCS) and platelet-derived growth factor (PDGF)-stimulated incorporation of [3H]thymidine into pig aortic smooth muscle cell (ASMC) DNA was decreased by agents that either stimulated the synthesis (forskolin) or inhibited the breakdown (3-isobutyl-1-methylxanthine, IBMX) of cAMP. FCS-stimulated incorporation of [3H]thymidine into DNA was also reduced by selective inhibitors of cAMP-specific phosphodiesterase (PDE IV) (Ro-20-1724, rolipram) and cGMP-inhibited cAMP PDE (PDE III) (SK&F 94836). IBMX, Ro-20-1724, rolipram and SK&F 94836 enhanced forskolin inhibition of DNA synthesis. Alone, rolipram was a relatively weak inhibitor of FCS-induced ASMC DNA synthesis (IC25 greater than 20 microM); however, in the presence of a threshold concentration of SK&F 94836 (20 microM), the potency of rolipram increased (IC25 = 4 microM), suggesting synergy in the actions of PDE III and PDE IV inhibitors. SK&F 94836 and rolipram elicited 30% and 37%, respectively, reductions in FCS-induced ASMC proliferation and potentiated the inhibitory actions of forskolin. PDE III and PDE IV inhibitors alone, exerted minimal effects on ASMC cAMP levels after a short term (10 min) or long-term (2 or 24 hr) exposure, but enhanced forskolin-induced accumulation of cAMP. ASMC spontaneously released cAMP into the extracellular medium, a process that was increased by forskolin. PDE III and PDE IV inhibitors had no effect alone on cAMP extrusion but enhanced the effect of forskolin. Exposure of ASMC to forskolin or SK&F 94836 for 15 min increased the activity ratio (AR) of cAMP-dependent protein kinase from 0.05 to 0.17 and 0.23, respectively. Ro-20-1724, alone, did not affect cAMP-dependent protein kinase but enhanced the stimulatory effect of forskolin (AR = 0.37) and SK&F 94836 (AR = 0.27). Agents that increased cGMP synthesis (glycerol trinitrate, atrial natriuretic factor) or decreased its hydrolysis by selectively inhibiting cGMP-specific PDE (PDE V) (zaprinast) exerted no effects on FCS- or PDGF-stimulated [3H]thymidine incorporation into DNA either alone or in combination. The cytosolic fraction of pig ASMC contained four cyclic nucleotide PDEs which were categorized as PDE V, Ca2+/calmodulin-stimulated PDE (PDE I), PDE III and PDE IV. PDE I and III activities were also associated with the particulate fraction. The results demonstrate that inhibitors of PDEs III and IV alone or in combination with forskolin, reduce ASMC DNA synthesis and proliferation, through an action likely to involve elevation of intracellular cAMP. In contrast, inhibition of cGMP hydrolysing PDE subtypes (I and V) exerted no effect on DNA synthesis in this cell type.     

Child pedestrian injury 1978-87.

OBJECTS: to report the incidence of child pedestrian injury in New Zealand and review prevention strategies. METHODS: examination of National Health Statistics Centre mortality and public hospital morbidity data from 1978-87. RESULTS: over the ten year period, there was an annual average of 30 deaths (3.6/100,000 per year) and 411 hospitalisations (49.4/100,000 per year) for child pedestrian injury. There has been no significant reduction in the fatality or hospital morbidity rate over this time. Pedestrian fatality rates are highest for boys and for children in the youngest age groups. Hospitalisation rates are over 2.5 times higher for Maori children than for nonMaori children. CONCLUSIONS: child pedestrian injury is an important public health problem in New Zealand for which there are few established prevention strategies. Controlled studies aimed at the identification of modifiable environmental factors are required.     

DNA flow-cytometric analysis in colorectal cancer: A comparison of metastasizing and non-metastasizing tumours

The most common cause of death in patients with colorectal cancer is metastatic liver disease. In order to identify patients at a high risk of developing hepatic secondaries from colorectal cancers, DNA content was measured in metastasizing colorectal primaries (Group I, n= 32) as well as in their subsequently resected liver secondaries and in sections of non-metastasizing colorectal cancers (Group II, n= 25). A modified interpretation system involving both a DNA index and percentage of cycling cells (those in S and G2 + M phases) was developed. DNA content was measured in paraffin-embedded sections by flow cytometry using internal controls (human peripheral blood mononuclear cells) and non-malignant tissue controls (19 patients with diverticular disease). In Group I there were significantly more tumours with both abnormal ploidy (aneuploid or abnormal tetraploid peak) and > 15% cycling cells compared with Group II (Chi-squared; P= 0.034). The combination of abnormal ploidy and > 15% cycling cells was superior to Dukes’ classification for identifying metastasizing tumours (Logistic Regression; P= 0.047). However, it was not possible to discriminate between the two groups using either DNA ploidy or the percentage of cycling cells alone. The metastasizing colorectal cancers exhibited similar DNA ploidy characteristics and had a similar percentage of cycling cells compared with their liver metastases. These results suggest that tumour DNA ploidy plus the percentage of cycling cells may predict the development of liver metastases and thus survival in patients with colorectal cancer.     

Variability of house-dust-mite allergen levels within carpets

Sensitization and exposure to house-dust-mite allergens is an important cause of asthma. Standardized, reliable, and reproducible methods for measuring exposure are essential for the assessment of the relationship between exposure, sensitization, and asthma. This study investigated the variability of the house-dust-mite allergen Der p 1 concentration in reservoir dust collected within whole carpets in living rooms and bedrooms. The carpets of nine bedrooms and 11 living rooms were sampled. Each room was divided into 1 m² areas measured from wall to wall where the carpet was accessible. Reservoir dust samples were collected by vacuuming each 1 m² area for 2 min. Der p 1 was assayed by a two-site monoclonal-antibody-based immunometric ELISA. Der p 1 was detectable in the carpets of nine bedrooms and six of the 11 living rooms. Within these 15 rooms, there was a wide range of Der p 1 levels. The smallest range of allergen within single room was 0.9 μg Der p 1/g dust (0.2 and 1.1 ng/g; 5.5-fold difference), and the largest was 149.2 μg Der p 1/g dust (0.8 and 150 μg/g; 192-fold difference). The mean range of allergen levels in the living rooms was 11.5 jig Der p 1/g of dust, and the mean coefficient of variation of these rooms was 80.2%. illustrating the huge variation of mite allergen levels within each room. The variation within bedrooms was also large, with a mean coefficient of variation value of 88.7%. The coefficient of variation was significantly lower around soft furnishings or beds (57%) than in the rest the room (89.3%), with the mean difference being 32% (95% CI 27ndash;63%; P=0.04). In conclusion, this study has shown that there is a great variation of Der p 1 levels between areas within a room. No consistent pattern of distribution of mite allergen within a room was found. Der p 1 levels in areas around soft furnishings and beds varied less than the levels in the rest of room.     

ATRX encodes a novel member of the SNF2 family of proteins: mutations point to a common mechanism underlying the ATR-X syndrome

It was shown recently that mutations of the ATRX gene give rise to a severe, X-linked form of syndromal mental retardation associated with alpha thalassaemia (ATR-X syndrome). In this study, we have characterised the full-length cDNA and predicted structure of the ATRX protein. Comparative analysis shows that it is an entirely new member of the SNF2 subgroup of a superfamily of proteins with similar ATPase and helicase domains. ATRX probably acts as a regulator of gene expression. Definition of its genomic structure enabled us to identify four novel splicing defects by screening 52 affected individuals. Correlation between these and previously identified mutations with variations in the ATR-X phenotype provides insights into the pathophysiology of this disease and the normal role of the ATRX protein in vivo.      

A retrospective study of the effects of the Lymphapress pump on lymphedema in a pediatric population.

We studied the effects of the Lymphapress pump (LP; Global Medical Imports, Digby, NS, Canada) retrospectively on 16 children with primary or secondary lymphedema of the upper or lower extremities by measuring the volume and circumference of the limbs before and after treatment. We reviewed medical charts for data on age, sex, length of disease process, grade of lymphedema, frequency and duration of treatment, and pump pressures used. We recorded changes in limb size before and after pumping in terms of the mean percentage difference between the affected and unaffected limb at both time points to allow for growth of the child and the extremity. On volumetric measures, thirteen (93%) of the subjects showed a clinical trend towards sustained maintenance or reduction in size of the lymphedematous limb(s). The reduction in the pump pressure at start of the treatment to that required to maintain the size of the limb was statistically significant (p = 0.0036). Fourteen (88%) of the subjects had no complications directly attributable to the pump, whereas two had complications that were probably unrelated to LP. Overall, there was a clinical trend towards reduction or maintenance of the lymphedematous limb size in children using LP without notable adverse sequelae.     

Adenocarcinoma in Childhood Barrett's Esophagus: Case Documentation and the Need for Surveillance in Children

A 17-yr-old boy underwent esophagectomy for multifocal high-grade dysplasia and adenocarcinoma complicating Barrett's esophagus (BE). He is believed to be the first child or young adult to have prolonged healthy survival following resection of esophageal adenocarcinoma. Dysplasia in a short retained segment of his Barrett's mucosa appears to have regressed with acid-suppressing therapy. Of nine other reported cases of adenocarcinoma in young people 11-25 yr of age, all died. All had progressive dysphagia and an esophageal mass at presentation, unlike our patient who had only histologic evidence of cancer at presentation. This was found only after repeated and extensive biopsy of the esophagus. We conclude that adenocarcinoma does occur under age 25 yr as a complication of BE arising in childhood, and it may be curable if diagnosed early. Endoscopic surveillance with multiple stepwise biopsies, beginning at age 10 yr, is suggested in those few children who have BE with specialized mucosa and goblet cells.     

Interventionelle Therapieverfahren bei akuter nekrotisierender Pankreatitis

The clinical course of acute pancreatitis is variable. Severe pancreatitis is observed in up to 20% of cases and is associated with high mortality rates of up to 40%. The most serious complication is the infection of the (peri-)pancreatic necroses. The therapeutic goal is debridement of the infected material. Whereas surgical methods still represent the gold standard, minimally invasive interventional approaches are gaining importance. This article reviews the different interventional procedures, particularly percutaneous, CT-guided drainage and necrosectomy. Furthermore, an overview of published studies about interventional therapy in patients with acute necrotizing pancreatitis is given.