Iwo Jima: 50th anniversary surprise

Retained metal fragments frequently are visualized in x-ray examinations of wounded combat veterans. Retained projectiles (bullets) are seen less often because of surgical removal.     

Dental caries in 5-, 7-, 9- and 11-year-old schoolchildren during a 9-year dental health campaign in The Hague

Abstract In the autumn of 1969, 1972, 1975 and 1978 clinical and radiographic dental examinations were carried out on about 800 children in The Hague of kindergartens, and 2nd, 4th and 6th grades of elementary schools. The aim of this investigation was to assess what changes, if any, in dental health may have taken place as a result of the campaign ‘Haagse Aktie’, based on dietary and dental health education. In the 5-, 7- and 9-year-old children no differences in dental health were found between 1969 and 1972. The first considerable improvement was found in 1975, especially in children from high social levels. In 1978 the children showed an even better dental health, compared with 1975. In the 5-year-old children the average dsmfs was 6.8. The average D3MFS in children of 7, 9 and 11 years of age in 1978 was 1.8, 3.9 and 8.2. At all socioeconomic levels the improvement of dental health was due to a considerable increase in the percentage of caries free children between 1975 and 1978; 27.6%, 51.8%, 21.2% and 7.4%, respectively, of the 5-, 7-, 9- and 11-year-old children were caries free in 1978, compared with 10.0%, 14.2%, 3.1 % and 0.9% in 1975. However, the reason for the reduction in caries is not known: it can only be the subject of speculation.     

Tooth discoloration induced by dental materials

Tooth discoloration after endodontic treatment is frequently attributed to drugs and filling materials. In this in vitro study the staining potential of various dental materials was investigated by means of a visual method to determine tooth color. Extracted human premolars were prepared, and the following materials were introduced into the pulp cavities: Cavit, Durelon, Dycal, Fletcher's cement, IRM, AH26-silver free, gutta-percha, Duo Percha, Fuji ionomer, and zinc phosphate cement. Before the materials were applied, the original tooth color was assessed on the external buccal tooth surfaces. Further color determinations were undertaken at regular intervals for 6 months after the materials were introduced. Durelon, Fuji ionomer, Fletcher's cement, and zinc phosphate cement did not induce measurable tooth discoloration. Cavit, Dycal, gutta-percha, and IRM caused a mild stain. For the teeth filled with AH26-silver free and Duo Percha, a moderate discoloration was recorded.     

Carcinoma of the breast: detection with MR imaging versus xeromammography

Detectability of breast cancer with magnetic resonance (MR) imaging versus xeromammography was quantitatively compared. MR images were obtained of breasts of 120 women who underwent xeromammography. T1 values were determined for masses larger than 2 cm. Cancer was histologically confirmed in 39 breasts and was considered excluded from 81 due to results of biopsy, cyst aspiration, or sonography or absence of change in xeromammographic findings over time. Images were blindly interpreted by three observers, and results were expressed as receiver operating characteristic curves. Detectability of breast cancer was substantially better with xeromammography than with MR imaging for all observers (P less than .03, 10(-6), and .001). On MR images, spiculation of a mass, distorted architecture, skin thickening, and nipple or skin retraction were specific but relatively insensitive indicators of cancer. Masses with smooth, distinct margins and signal intensity greater than that of fat on T2-weighted images were always benign. Other findings and T1 values were not diagnostically useful. The authors conclude that xeromammography is superior to MR imaging in detection of breast cancer.     

Experimental periodontal disease in rats induced by plaque-forming microorganisms

Three different capsule or extracellular slime producing microorganisms: Rothia, Neisseria and Bacterionema were tested in SPF Osborne-Mendel rats for their ability to stimulate plaque formation and their effect on the gingiva. Gingival inflammation in the rats was evaluated in histological sections of buccal gingivae.
All three the test strains were found to stimulate plaque formation. The high plaque score in the inoculated groups of rats was found to be attended by an increase in the area of infiltrated gingival tissue.     

Effects of High Intensity Training by Heart Rate or Power in Recreational Cyclists

Technological advances in interval training for cyclists have led to the development of both heart rate (HR) monitors and powermeters (PM). Despite the growing popularity of PM use, the superiority of PM-based training has not been established. The aim of the present study was to investigate the relative effectiveness of HR-based versus PM-based interval training on 20 km time trial (20km TT), lactate threshold (LT) power, and peak aerobic capacity (VO₂max) in recreational cyclists. Participants (n =20; M age=33.9, SD =13) completed a baseline 20km TT to establish their VO₂max and LT and were then randomly assigned to either HR-determined or PM-determined training sessions. Over a period of up to 5 weeks participants completed 7.2 (± 1.1) interval training sessions at their specific LT for their respective interval training method. Repeated measures analyses of variances (ANOVAs) showed that both HR-based and PM-based training groups significantly improved their LT power (F(1,16) = 28., p < 0.01, eta² = 0.63) and 20km TT time (F(1,16) = 4.92, p = 0.04, eta² = 0.24) at posttest, showing a 17 watt increase (9.8%) and a near 3-and-a-half minute improvement (7.8%) in 20km TT completion time. There were no significant group (HR vs. PM) x time (baseline vs. posttest) interactions for 20km TT completion time, LT power, or VO₂max ratings. Our results coincide with the literature supporting the effectiveness of interval training for endurance athletes. Furthermore, our findings indicate that there is no empirical evidence for the superiority of any single type of device in the implementation of interval training. This study indicates that there are no noticeable advantages to using PM to increase performance in the average recreational cyclist, suggesting that low cost HR monitor are equally capable as training devices.

Key points

• Interval training improves performance for recreational cyclists as measure by changes in lactate threshold watts and 20km time trial time
• No evidence of superiority of either heart monitor training and power meter training
• Low cost heart rate monitors are equally capable as training devices

Key words: Power, hear rate, training     

Expression of a kinase-deficient IGF-I-R suppresses tumorigenicity of rhabdomyosarcoma cells constitutively expressing a wild type IGF-I-R

Previous results have shown that the insulin-like growth factor type I receptor (IGF-I-R) plays a critical role in the control of rhabdomyosarcoma (RMS) growth. The purpose of this study was to investigate whether a mutated IGF-I-R, when expressed in RMS cells, may interfere with the function of the endogenous wild-type IGF-I-R. We also examined whether the expression of a mutated IGF-I-R may induce phenotypic changes in RMS cells. We used here the mutated IGF-I-R with a lysine to arginine residue 1003 substitution, called IGF-I-KR, which carries a mutation in the ATP-binding domain of the intracellular β subunit, while the extracellular, ligand binding α subunit remains unchanged. We observed that the expression of this mutated IGF-I-KR markedly decreased the response of RMS cells to stimulation with IGF-I. While stimulation with IGF-I increases the autophosphorylation of IGF-I-R in the parent cells, stimulation with IGF-I failed to produce a comparable increase in autophosphorylation in the cells expressing the mutated IGF-I-KR. We also observed a decreased plating efficiency of cells expressing the mutated IGF-I-KR. Consistently, a decrease of RMS growth in vivo was observed in an animal model. Our data suggest that the IGF/IGF-I-R signaling pathway may be inhibited by expressing a mutated IGF-I-KR and that such a mutant gene could be utilized in developing novel therapeutic strategies to suppress RMS growth. Int. J. Cancer 76:223–227, 1998. Published 1998 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.