Restraining factors affecting setting expansion of phosphate-bonded investments

Abstract — The effects of several factors on the setting expansion of a phosphate-bonded investment used in a steel casting ring were studied. The results show that the setting expansion under the conditions analyzed can be characterized only as a most unreliable means to partly compensate for the solid thermal contraction of casting alloys in a precision-requiring technique.     

Pathogenesis of a Bisdiamine-Induced Malformation Complex in Rat Resembling DiGeorge Syndrome

Abstract Administration of the antispermatogenic agent bis-diamine (N, N'-bis-(dichloroacetyl)-1, 8-octamethylenediamine) to pregnant rats produced a malformation complex resembling DiGeorge syndrome in man. The malformations consisted of hypoplasia or aplasia of the thymus, persistent truncus arteriosus, tetralogy of Fallot, aberrant subclavian artery and other cardiovascular anomalies, as well as hypoplasia of the parathyroid gland, thyroid gland, and the spleen. The malformation complex appeared with a high incidence when the drug was administered on day 9.5 or day 10 of gestation.
Since the connective tissues of the thymus, aorticopulmonary septum, smooth muscles of the media of the aortic arch artery, and connective tissues of the parathyroid and the thyroid glands, are of neural crest origin, and since the time of their migration is around day 10 of gestation, we postulate that the action of bis-diamine might be involution of the migration of the neural crest cells and of its pathways.
We further suggest from the findings of persistent atrioventricular canal and hypoplasia of the spleen, that the drug must have also affected the growth of mesenchymal cells, which originate from the endocardial epithelial cells.     

Management of colorectal polyps in children

Forty-two patients each with a colorectal polyp have been treated in our hospital over the past 10 years. In twenty-two cases the polyps were noted in the rectum, nine in the sigmoid colon, seven in the descending colon and four in the transverse colon. Each patient had only one polyp. Hematochezia was the main symptom in 29 patients, prolapse of the polyp from the anus in 10, abdominal pain due to intussusception in two and no symptoms were observed in one. Auto-amputation of the polyp was considered to have occurred in five patients. Twelve rectal polyps were resected from a transanal operation, and another 25 polyps were removed endoscopically with electric cautery. We have had no experience of endoscopic complications such as bleeding or perforation. A histological examination revealed an adenoma in one patient. Other polyps were non-neoplastic and were classified as juvenile, inflammatory and hyperplastic in 30, two and four patients, respectively. There have been no recurrences of polyps to date.     

A long-term suppression by α-interferon of Philadelphia chromosome in children with chronic myelogenous leukemia

An 8 year old girl with adult type Philadelphia (Ph¹)-positive chronic myelogenous leukemia received natural α-interferon therapy in the chronic phase. Complete suppression of the Ph¹ clone of bone marrow cells was achieved after 1 month of therapy, which was determined by disappearance of rearranged breakpoint cluster region (BCR) gene in Southern blot analysis. Complete hematological remission was also attained following 2 months of therapy. Both the suppression and the hematological remission have been sustained for 24 months with α-interferon. in spite of the detection of the chimeric BCR/ABL mRNA in her bone marrow by polymerase chain reaction assay 12 months after therapy.     

Clinical observation of 14 cases of childhood polyarteritis nodosa in Japan

An epidemiological survey of childhood polyarteritis nodosa was conducted at 1290 hospitals followed by a secondary survey of hospitals that had therapeutic experience with the disease. Fourteen cases obtained from these surveys were studied clinically. The male-female ratio was 4:3. The mean age at onset was 10.6 years. To established the diagnosis, skin biopsy was performed in 43%, retrograde aortography in 21%, and kidney biopsy in 14% of cases. Non-specific symptoms such as fever (86%), skin eruption (50%), arthritis (50%), myalgia (50%), abdominal pain (43%) and hypertension (36%) were often noted as clinical findings at the initial visit. Throughout the clinical course, symptoms considered to be caused by local angiopathy, including interrupted blood circulation, were frequently noted. On blood tests, no specific findings other than acute inflammatory reaction were observed. Steroid preparations were used for treatment in all cases but one, and about half of them are presently free from steroids. Immunosuppressants were administered in 10 cases. As for prognosis, all patients are alive, but untoward sequelae were noted in 36% of cases. The results of the present survey reinforced the difficulty of establishing a final differential diagnosis because specific findings were scarce for this disease, as stated in previous reports. Establishing a method for early diagnosis by gathering and analyzing more data in detail will be necessary in the future.     

Arrhythmias in Centenarians

Background: Many studies have shown an increase in the prevalence of arrhythmias with advancing age. However, little is known about arrhythmias in centenarians. Method and Results: Thirty-two Japanese centenarians aged 100–106 years (14 males, 18 females) were studied. All of them had 12-lead EGGs, and 22 also had 24-hour ambulatory monitoring. As controls, 89 healthy Japanese elderly from the same geographic area underwent 12-lead ECG. Their mean age was 75 ± 6 years with a range of 63–93 years, and there were 28 males and 61 females. Twenty-three of them also had Holter ECGs. On the 12-lead ECG, the heart rate was slightly, but significantly, higher in the centenarians (76.8 ± 12.7 beats/min) than that in the elderly subjects (74.9 ± 5.9 beats/min, P < 0.005). PQ and QT_C were significantly longer in the centenarians (174 ± 29 and 439 ± 33 msec, respectively) compared with the elderly subjects (158 ± 23 and 417 ± 31 msec, P < 0.005 and P < 0.001, respectively). Supraventricular premature beats (SVPBs) were observed in 31% of the centenarians and in 4% of the elderly subjects (P < 0.001). First- and second-degree AV block was recorded in 25% of the centenarians and 1% of the elderly subjects (P < 0.001). Right bundle branch block was found in 19% of the centenarians and 7% of the elderly subjects (P < 0.05). There were no differences in the frequency of ventricular premature beats (VPBs) or QRS voltage. On the Holter ECG, there were no significant differences in average heart rate, maximum heart rate, minimum heart rate, or the longest RR interval. A subgroup of centenarians had frequent SVPBs. However, none of them had > 1,000 VPBs/day as opposed to four elderly subjects (P < 0.01). Atrial fibrillation was not observed in any records of the centenarians despite the presence of frequent SVPBs. Conclusion: These data suggest that conduction disturbances of the AV nodal—His-Purkinje system and frequent SVPBs are common in centenarians, whereas very frequent VPBs and atrial fibrillation seem less common.     

Response of skin blood volume, velocity and flow to local warming in newborns, measured by laser Doppler flowmetry

BACKGROUND: In order to know the response of the skin microcirculation to local warming, we determined changes in the skin blood volume (Vol), velocity (Vel) and flow (F) by using a new laser Doppler device on newborns. METHODS: The study subjects were 39 infants whose gestational age was 34.1 +/- 2.8 weeks and birth weight was 2189 +/- 572 g. The study was performed from 8 h postnatally to 28 postnatal days. We measured skin blood volume, velocity and flow at 36 degrees C (Vol36, Vel36, F36), and each value at 5 min (Vol44-5, Vel44-5, F44-5) and 10 min (Vol44-10, Vel44-10, F44-10) after local warming was applied at 44 degrees C and the response curve of each parameter was obtained. Subsequently, serial changes in the response of skin microcirculation to local warming were investigated in nine very low birth weight (VLBW) infants (28.3 +/- 0.9 weeks, 1150 +/- 148 g) and 12 low birth weight (LBW) infants (32.8 +/- 1.3 weeks, 1971 +/- 292 g). The F36, the increment rate of blood volume (delta Vol) and the increment rate of blood velocity (delta Vel) were obtained within 24 h, from day 1 to day 7 and from day 8 to day 30 in both VLBW and LBW infants and from day 31 to day 60 and at more than 61 days in VLBW infants. The F36, delta Vol and delta Vel were compared during the study periods in VLBW and LBW infants. All results were expressed as mean +/- SD. RESULTS: The results showed that F36/F44-10 and F44-5/F44-10, Vol36/Vol44-10 and Vol44-5/Vol44-10, Vel36/Vel44-10 and Vel44-5/Vel44-10 were 0.25 +/- 0.09 and 0.74 +/- 0.17, 0.58 +/- 0.14 and 0.94 +/- 0.08, 0.42 +/- 0.12 and 0.79 +/- 0.15, respectively. Different modes of delivery did not have a significant effect on this response. The F36 in VLBW infants was high during the early neonatal period and gradually decreased with postnatal age. The delta Vol was low in VLBW infants during the neonatal period and gradually increased. The F36 in VLBW1-7 was significantly higher than in LBW1-7 (P < 0.01) and full-term controls (P < 0.001). The delta Vol in VLBW1-7 was 0.26 +/- 0.23, which is significantly lower than in LBW1-7 (0.57 +/- 0.17, P < 0.001) and full-term controls (0.77 +/- 0.21, P < 0.001). The delta Vel in VLBW1-7 and LBW1-7 was significantly higher than in controls (P < 0.05). CONCLUSIONS: The skin blood flow increased continuously when local warming was applied at 44 degrees C. This high blood flow and limited potential of vasodilatation are the characteristics of the skin microcirculation in VLBW infants during the neonatal period.     

IMMUNOHISTOCHEMICAL STUDY OF OVEREXPRESSION OF FIBROBLAST GROWTH FACTOR-1 (FGF-1), FGF-2, AND FGF RECEPTOR-1 IN HUMAN MALIGNANT SALIVARY GLAND TUMOURS

Fibroblast growth factor-1 (FGF-1) and FGF-2 are broad spectrum mitogens. The expression of FGF-1, FGF-2, and their receptor, FGF receptor-1 (FGFR-1), was examined in malignant salivary gland tumours and normal salivary glands, using immunohistochemical methods. In seven cases of adenoid cystic carcinoma (ACC), both duct-like cells and modified myoepithelial cells were apparently immunopositive for FGF-1, FGF-2, and FGFR-1. In five cases of mucoepidermoid carcinoma (MC), all three types of tumour cells including epidermoid cells, mucous cells, and intermediate cells expressed immunoreactive FGF-1, FGF-2, and FGFR-1. In these malignant salivary gland tumours, increased expression of FGFR-1 correlated with the intensity of both FGF-1 and FGF-2 immunoreactivity. In contrast to malignant salivary gland tumours, eight cases of normal salivary gland showed negative immunostaining for FGF-1, FGF-2, and FGFR-1 while four cases were weakly immunoreactive for FGF and its receptor. These results demonstrate that malignant salivary gland tumours overexpress FGF-1, FGF-2, and FGFR-1 compared with normal salivary glands and suggest that these growth factors may play an important role in facilitating neoplastic progression in human salivary glands.     

Effect of Alcoholic and Low-pH Soft Drinks on Fluoride Release from Compomer

Purpose: The purpose of this study was to evaluate the amount of fluoride released from compomer restorative materials after immersion in various media. Materials and Methods: In this test, four materials were used: three compomers (Dyract, Dentsply, Konstanz, Germany; Compoglass, Vivadent, Schaan, Principality of Liechtenstein; and Xeno, Sankins, Tochigi, Japan) and one resin‐modified glass ionomer cement (Fuji II LC, GC, Tokyo, Japan). There were four test solutions: one alcoholic (whiskey), two low‐pH drinks (Coca‐Cola, orange juice), and one deionized water. Over a period of 60 days, the tested specimens were immersed in the test solution for 3 hours every day, then kept in deionized water. The fluoride released was detected by using a fluoride ion selective electrode connected to a microprocessor ion analyzer. The fluoride ion concentration (ppm) of the test solutions and deionized water was recorded after 1, 2, 3, 4, 7, 30, and 60 days. Electron probe microanalysis was used for surface analysis of the fluoride released. Results: When immersed in low‐pH soft drinks, compomer showed a significantly higher fluoride release than when immersed in deionized water (p <.0001). For specimens immersed in Coca‐Cola, the fluoride release levels (pg/cm², mean ± SD) at 1, 7, and 60 days for Dyract (91.6 ± 1.8, 39.3 ± 3.1, 10.5 ± 0.9), Compoglass (129.5 ± 0.9, 66.5 ± 2.7, 19.0 ± 0.3), Fuji II LC (147.0 ± 4.2, 50.8 ± 3.1, 27.6 ± 3.0), and Xeno (73.6 ± 3.2, 27.3 ± 2.1, 6.6 ± 0.6) demonstrated the trend of significantly lower releases with time in water solution. Over a 60‐day period, materials immersed in 100% orange juice released the highest amount of fluoride, which could be attributable to the erosive effect of the medium. Materials immersed in deionized water released the least amount of fluoride. Among the tested compomers, Compoglass released the most fluoride. CLINICAL SIGNIFICANCE The results of this study indicate that, at low pH, compomer restorative materials tend to release more fluoride.