Dialysis-associated dementia.

Two patients from an Australian Dialysis Centre developed a progressive neurological disorder with features similar to those recently discribed as the snydrome of Dementia Dialytica. These two patients are reported here and this newly recognised syndrome reviewed.


Assessment of cardiovascular side effects of therapeutic doses of tricyclic anti-depressant drugs.

An assessment of the side effects of therapeutic doses of tricyclic anti-depressant drugs was attempted in 32 patients with depressive illness. The patients studied had no evidence of clinical heart disease or hypertension and were not receiving any other drugs. Moderate increase in heart rate and mild prolongation of atrioventricular conduction occurred. No significant effect on the corrected QT interval or blood pressure was found. There was no correlation between the increased heart rate, prolongation of the atrioventricular conduction time (PR interval) and plasma nortriptyline levels measured in 20 out of 32 patients.


The relationship of red cell membrane lipid content to red cell morphology and survival in patients with liver disease.

The relationship of red blood cell (RBC) membrane lipid content to RBC morphology and survival was studied in patients with liver diseases. An increase in RBC cholesterol and phospholipid was detected in most patients with hepatocellular disease or cholestatic jaundice but the alteration in RBC lipid content did not correlate with RBC survival. The main abnormality of RBC morphology observed was the presence of macrocytes and target cells. In a small proportion of patients (approximately 3%) with severe hepatocellular disease, significant numbers of severely deformed ("spur") cells were seen. In these patients haemolysis was moderately severe and the RBC lipid profile showed increased membrane cholesterol without a concomitant increase in phospholipids. It is concluded that only in patients with "spur" cell anaemia do the morphological alterations lead to premature removal of cells from the circulation. The cause of the shortened RBC survival in jaundiced patients without "spur" cells remains to be determined.


The significance of HL-A W27 in ankylosing spondylitis and Reiter's syndrome with three family studies.

So as to test the diagnostic significance of tissue typing in an Australian population the HL-A antigens of forty-seven patients with Ankylosing Sondylitis and six patients with Reiter's Syndrome were compared with those found in three hundred and six controls.  Since HL-A W27 was found in 92% of the patients with Ankylosing Spondylitis and all patients with Reiter's Syndrome it is concluded that these diagnoses should be questioned if this antigen cannot be demonstrated.  In three family studies it was apparent that Ankylosing Spondylitis only occurred in those who had inherited HL-A W27 so that the absence of the antigen may help to identify those family members who will not develop the disease.  Notwithstanding the association demonstrated the data argue against a close and simple linkage between the antigen and these diseases.


The floppy mitral valve syndrome--a review of fourteen patients requiring valve surgery.

The correlation of clinical features with the operative findings in 14 patients with a floppy mitral valve is discussed.  The clinical course is typified by rapidly progressive disability.  An abrupt deterioration was present in five of our subjects and this may be due to  rupture of chordae tendinea or stretching of the valve apparatus.  The redundancy of the anterior cusp in 13 of our series may explain the absence of mid systolic clicks in all except one patient.  The diagnosis of prolapse can be difficult to make prior to surgery because the prolapsed cusp may be masked by the regurgitant contrast medium.  Hypokinesis and prominent inflow sacculation of the left ventricular inflow tract suggest an associated myocardial abnormality.  Calcium was present in one valve and thus mitral valve calcification does not exclude the possibility of a floppy valve in patients with mitral regurgitation.


Reduction of platelet/fibrin deposition in haemodialysers by aspirin administration.

Aspirin, a drug known to inhibit the platelet release reaction, was evaluated for its potential in reducing platelet/fibrin deposition in hollow fibre dialysers.  Twelve patients with endstage renal failure were given the drug under controlled conditions while being treated by regular maintenance haemodialysis.  After base-line data were collected during a mean number of 11.7 dialysers per study, observations were repeated for a mean of 9.3 dialysers, during which time each patient took 600 mg of aspirin by mouth every morning.  Thrombus deposition, measured by volume loss of the blood compartment of the dialyser fibre bundle, was significantly reduced (P less than 0.05) during aspirin administration in six of the 12 studies.  The mean volume loss of the fibre bundle in these six studies (responders) was 25% per dialysis during the control period, and 13% with aspirin; in the other six studies (non-responders), the mean values were 8% and 6% respectively.  Aspirin prolonged the bleeding time in all patients, and significantly (p less than 0.05) impaired platelet aggregation in both responders and non-responders.


Nutrition in the Australian aborginines--effects of the fortification of white flour.

The nutritional status of 66 part Aborginines was re-examined in 1974--with particular reference to blood levels of haemoglobin and vitamins--after white bread fortified with iron and the vitamins B1 and PP (niacin) had been available for six and half months to the population of Bourke, New South Wales.  The results found in 1971 and 1974 are compared.  A significant improvement from deficient to acceptable blood levels of vitamins B1 and B6 was found in 44% and 52% of the subjects respectively.  This attributed to the comsumption of fortified bread since the levels of the other vitamins had remained either unchanged or worsened.  The biochemical improvement in vitamin B6 is attributed to the sparing effect of vitamin PP on vitamin B6 requirement because the conversion of tryptophan to niacin is impaired in vitamin B6 deficiency.  Iron deficiency anaemia in children had decreased by 50% but this could have been due to many other factors besides the iron which had been added to the bread.  Clinically there was a marked decrease in angular stomatitis and skin xerosis which could be related to the biochemical improvement of the two B-vitamins and a decrease in active trachoma and suppurative otitis media probably due to intensive treatment received since 1971.  The results of this study and the extent of biochemical vitamin B1 and B6 deficiency found in other groups, indicate that fortification of bread may be of benefit to the community as a whole.


The prevalence of chronic gastritis in patients with gastric ulcer.

Multiple gastric biopsies were performed with a duodenofiberscope in 58 Chinese subjects.  All 58 cases had a gastric ulcer crater, demonstrated by endoscopy, or barium meal, or both.  Histological sections of the gastric biopsies showed chronic atrophic gastritis in 12 (20.6%), chronic gastritis in 31 (53.4%), and acute-on-chronic gastritis in 11 (19%).  Only two cases or 3.4% had normal gastric mucosa, while 54 cases or 93% had some form of chronic gastritis, on the gastric biopsy.  The gastritis was associated with intestinal metaplasia in 16 cases (27.6%), while two cases had histological evidence of gastric atypia.  No significant difference was found in the mean basal and peak acid outputs among the three groups of gastric ulcer cases with chronic atrophic gastritis, chronic gastritis, and acute-on-chronic gastritis.  The high frequency of chronic gastritis (93%) occurring in patients with gastric ulcer in the present series suggests that chronic gastritis may be an important aetiological factor in the pathogenesis of gastric ulceration.


Effect of stasis on intestinal enzyme activities.

Activities of the small intestinal mucosal enzymes lactase, sucrase, maltase, alkaline phosphatase and N-acetyl-beta-glucosaminidase were studied in rats with surgically-induced upper intestinal stasis and in control animals. The first four are brush border enzymes, the latter a lysosomal enzyme. There was a reduction in the activities of all enzymes in the operated animals. The change lining was significant and most marked in mucosa the blind loop and gut distal to it; areas in which there is gross bacterial overgrowth and excessive levels of intraluminal deconjugated bile salts. The significance of these findings in relation to malabsorption consequent on bacterial contamination of the upper gut is uncertain and requires further study.


Phenytoin sensitivity in a case of phenytoin-associated Hodgkin's disease.

The case of a patient who developed Hodgkin's disease three years after commencement of therapy with phenytoin is presented.  Humoral and cellular immunological capacity were significantly depressed.  Phenytoin caused a striking increase in DNA synthesis when lymphocytes were culture in the presence of this drug, in contrast to significant inhibition in the lymphocytes of control subjects.  These findings are consistent with the hypothesis that both chronic antigenic stimulation and immunosuppression by phenytoin and involved in the induction of lymphoma.


Emphysema in Papua New Guinea--a pathological study.

The authors examined 47 lungs obtained at post mortem in Papua New Gunea.  These were inflated with formalin, fixed under pressure, sliced and examined for emphysema using a "point-counting" method.  There was no emphysema before the age of 30 years.  The pathological types encountered were similar to those in the United Kingdom.  In patients over 50 years of age there appeared to be little difference between the amount of emphysema present in Paua New Guinea and in the United Kingdom.  Enviromental air pollution seemed to be relatively unimportant in the pathogenesis.  Repeated lower respiratory tract infections may be more important.  Emphysema appeared to be more prevalent in lowland than highland dwellers.  The findings of this pathological study supported the clinical and epidemiological studies carried out concurrently, but independently by others.


A case of Hageman factor deficiency with myeloid leukaemia.

The co-existence of blastic transformation of chronic myeloid leukaemia and an isolated deficiency of coagulation factor XII (Hageman Factor), is reported.  In the absence of any evidence of factor XII deficiency in the patient's siblings and children, it is uncertain if this represents an acquired factor XII deficiency due to myeloid leukaemia, or the coincidental occurrence of myeloid leukaemia with this autosomal recessive condition.


Mycobacterium ulcerans in Australia.

The epidemiology of 39 case reports of infection with Mycobacterium ulcerans published during the past 25 years in Australia is presented.  A review is made of the laboratory findings of the strains found in Australia and of the contribution of Australian workers to the description, treatment and prevention of this disfiguring disease.


IgA-associated glomerulonephritis.

Mesangial IgA depostiiton was detected by routine fluorescent microscopy of 19 cases of glomerulonephritis.  Twelve patients had a variable degree of diffuse mesangial proliferative glomerulonephritis.  The heterogeneous histological findings in the other seven patients show that mesangial IgA deposition alone does not have diagnostic specificity.  However, when interpretation of the mesangial IgA deposition is complemented by clinical and histological information, a group of patients with the characteristic combined features can be distinguished.


The effect of impairment of renal function and dialysis on the serum and urine levels of clindamycin.

A single 150 mg oral dose of clindamycin was given to three healthy volunteers and 13 patients with varying degrees of renal functional impairment.  The mean peak serum levels in the two groups were 2.55 +/- 0.92 mug/ml and 3.39 +/- 0.68 mug/ml respectively.  In all patients the levels greatly exceeded the minimum inhibitory concentration for sensitive pathogens.  The serum half-life was extremely variable in patients with renal failure and bore no relationship to the glomerular filtration rate.  In the normal subjects 11.9% of the administered dose was excreted in the urine but in severe renal failure less than 1% of the bioactivity was detected in the urine in 24 hours.  The drug was not removed by haemodialysis.  In patients with mild to moderate impairment of renal function no dosage adjustment of clindamycin is necessary.  However, in those with severe renal failure some modification to dosage would be prudent and this should be monitored by measuring serum levels of the antibiotic.


A study of serum and myocardial digitoxin concentrations in man during cardiac arrest.

In 22 digitalized (of a total of 39) patients studied at random by radioimmunoassay during cardiac arrest, the mean serum digoxin concentration was 2.6 (+/- 1.86, range 0.6-8.2) ng/ml, significantly higher (P less than 0.001) than the "eudigitalized" concentration (1.3 +/- 0.52, range 0.5-2.3 ng/ml) determined under carefully standardized conditions in a non-toxic population.  Half of the arrest patients had serum digoxin levels in the toxic range (2.4 ng/ml or above), mainly due to significant renal failure (mean serum creatinine concentration 2.9 +/- 2.66 v. 1 +/- 0.26 mg/dl for non-toxic subjects, P less than 0.001), partly due to a higher mean daily digoxin dose (0.40 v 0.31 mg/day, P less than 0.05) and frequently associated with potent diuretic therapy (73 v 54%).  A smaller fraction of digitalized patients survived, both short- (27%) and long-term (14%), than did non-digitalized subjects (35% and 26%, respectively).  The mean myocardial digoxin concentration was 150 (+/- 63.3, range 52-252) ng/g with an average myocardial/serum ratio of 62.5 (range 38-91).  There were significant positive correlations between the serum digoxin and left-ventricular myocardial digoxin concentration (r=0.8107, P less than 0.01) or serum creatinine concentration (r=0.4637, P less than 0.001).


The effect of multiphasic biochemical screening on the diagnosis of primary hyperparathyroidism.

Experience of primary hyperparathyroidism (PHPT) at the Royal Brisbane Hospital was reviewed to determine the effect of multiphasic biochemical screening, introduced during 1970, on the rate of diagnosis of this disease.  In the period 1959-1970, there were 28 proved cases and, in the period 1971-1974, 41 cases, an increase from 2.5 to 11.7 cases per annum.  The main factor contributing to this increase was the inclusion of plasma calcium in the multiphasic screening programme, together with correction of the plasma calcium for the total protein concentration in the same blood sample.


The effect of carbenoxolone sodium on the plasma 11 hydroxycorticoid levels in chronic gastric ulceration.

The mineralcorticoid effects of carbenoxolone sodium are well established and seem related to the ulcer healing of the drug.  In the present study the plasma 11 hydroxycorticoid responses were assessed in 12 patients undergoing treatment with carbenoxolone for chronic gastric ulceration.  After treatment with carbenoxolone for one month the plasma 11 hydroxycoticoid levels rose significantly, suppression by dexamethosone was less marked and the normal diurnal periodicity was abolished.  Carbenoxolone therapy influences the results of tests designed to assess the function of the pituitaryadrenal axis and may lead to sub-clinical adrenocortical hyperfunction.


Bood vitamin levels in children with gastroenteritis.

Clinical evaluation and estimation of blood levels of vitamins A, E, C, B1, B2, B6 and of total carotenoids were carried out in 52 consecutive children admitted to the Royal Alexandra Hospital for Children in Sydney during the winter epidemic of diarrhoea.  The children included 37 Europeans and 15 Aboriginals, who were previously apparently healthy.  Of these, 19 Europeans and ten Abororigines were studied also after recovery.  The anthropometric, clinical, microbiological and biochemical data for each child is presented.  Vitamin treatment, duration of symptoms, severity of diarrhoea, stool microbiology and the role of secondary malabsorption as a main cause of the depressed plasma vitamin levels found is discussed.


A family study of coeliac disease.

Studies by Thompson, 1 Carter et al, 2 MacDonald et al. and McCrae 4 have all shown a high familial frequency of coeliac disease (CD).  The diagnostic criteria differed in each study; in Thompson's patients the diagnosis was based on clinical or historical data alone; in Carter's study response to a gluten-free diet was required, while in MacDonald's and McCrae's studies the diagnostic criteria included the demonstration of the lesion of CD by small bowel biopsy.  In MacDonald's study some asymptomatic cases were discovered and a few of these had normal fat balance results.  No hereditary pattern emerged from these studies though MacDonald postulated a dominant gene with variable penetrance while McCrae suggested that susceptibility to CD is inhereited multifactorially and that enviromental factors other than dietary gluten are of aetiological importance.  Hoffman et al. 5, on the other hand, have described discordance for CD in identical twins.


Detection of synovial cysts by transmission-emission scintigrams following intra-articular 169Yb-DTPA.

A new simple and safe technique for the detection of synovial cysts is described.  This investigation employs combined transmission-emission scintigraphy following intra-articular injection of 169Yb-DTPA.  Twenty-two joints were investigated in 18 patients.  A high degree of correlation was found between clinical findings and the results of this investigation.  The major advantages of this method are low local radiation to synovial linings, adequate visualisation of periarticular soft tissue, and small volumes required for intra-articular injection.


Spirometric standards from 387 healthy New Zealand children.

Vital capacity and forced expiratory volume in 1 s were measured in 387 healthy European and 16 non-European children aged from five to 11 years.  These measurements were correlated with height, sitting height, arm span, weight, lean weight and age in various combinations.  Suitable linear regression equations are presented from which these lung volumes may be predicted with confidence limits down to approximately +/- 400 ml and +/- 200 ml respectively.


Leukemias induced by 1-butyl- and 1-propyl-1-nitrosoureas in the rat.

The leukemogenic effect of 1-propyl- and 1-butyl-1-nitrosourea (PNU and BNU) was studied in Donryu and Sprague-Dawley rats, which received the chemical in their drinking water. BNU produced leukemia in 42 out of 46 (91%) of the Donryu rats, and the majority of the induced leukemia were myeloblastic type. In the Sprague-Dawley rats, the incidence of leukemia was 70% (47/67), of which 37%(13/35) were myelocytic leukemia, although the development of myeloblastic leukemia was still predominant (54%, 19/35). The leukemogenic activity of PNU was slightly lower than that of BNU; it produced leukemia in 64% (61/95) of the Donryu rats. The predominant type of induced leukemia was myelocytic leukemia (59%, 36/61). Therefore, it was demonstrated through the series of experiments using BNU and PNU that the strength of leukemogenic activity has a close relationship to the types of leukemia induced in animals. Both BNU and PNU, however, provide excellent disease models of myelogeneous leukemia in the human being.


Increased virus budding from Friend erythroleukemic cells treated with dimethyl sulfoxide, dimethyl formamide, and/or bromodeoxyuridine in vitro.

Chronically infected Friend leukemia cells (FLC), grown in the presence of dimethyl sulfoxide (DMSO) (2%, v/v), dimethyl formamide (DMF) (1% v/v), or bromodeoxyuridine (BrdU) (3 or 20 mug/ml) for 4 or 7 days, were examined under the electron microscope. It was found that at the 4th day all three compounds induced comparable increases in the number of budding viruses (3 to 5 times that of the control). At the 7th day, the number had remained relatively constant in the BrdU-treated cells in contrast to the cells of the DMSO- or DMF-treated cultures, which showed a further increase of budding viruses. The greatest increase was seen when BrdU was added in combination with either DMSO or DMF, and this was reflected in the apparent increase in the number of extracellular viruses seen in cell pellets. Scanning electron microscopy on whole FLC mounts provided a rapid means of counting budding viruses and a good correlation was obtained between these counts and those made on thin sections by transmission electron microscopy. Attempts to quantitate the number of released viruses in controls and treated cultures after 4 days of growth revealed a 5- to 10-fold increase per cell in the samples treated with a combination of BrdU and either DMSO or DMF. Thymidine failed to prevent the increase of budding viruses induced by BrdU treatment. The number of budding viruses found after treatment with 3 mug/ml BrdU in the presence of 12 mug/ml thymidine was at a level comparable to that found after the individual BrdU treatment Finally, although FLC always contained varying amounts of intracisternal particles, their number, as compared to the paired controls, always decreased after BrdU treatment.


Attempts to transform murine hemopoietic cells by Rauscher leukemia virus.

Primary Rauscher leukemia virus (RLV)-induced myeloid leukemias can produce many small clones in agar in the absence of a factor needed for the proliferation of normal myeloid cells. It seems that leukemic cells can more efficiently utilize the small amount of colony-stimulating factor (CSF) that is produced by them. At optimal stimulation by exogenous CSF, leukemic cells exhibit a poorer rate of proliferation than normal bone marrow cells. Hemopoietic cells can replicate the virus after infection in vitro. In some experiments, infection of normal bone marrow cells leads to the production of some cells with the same growth pattern as cells from primary leukemias.


Transformation of cells in human bone tumor cultures.

Two cell lines from tumors of 16 patients with osteosarcoma and two cell lines from 5 patients with giant cell tumor of bone showed conversion of cell type after 2 to 13 months in culture. Transformed cells of epithelial like morphology appeared in small focal areas and rapidly overgrew nontransformed cells. These cells were characterized by rapid growth, loss of contact inhibition, and growth in soft agar. Attempts to demonstrate virus(es) by electron microscopy, treatment with chemicals, or by inoculation of human cell lines were thus far unsuccessful. Antigens not present in parental cultures were observed in the transformed cells by fixed immunofluorescence test with sera of 13 and 20 osteosarcoma patients and 3 of 8 patients with giant cell tumor of bone. Absorption of positive sera with transformed cells of either osteosarcoma or giant cell tumor removed the reaction but not with absorption with heterophile material or mycoplasma. Presence of group-specific-like antigen (gs-3) in the transformed cells (but not in parent cultures) was shown by immunofluorescence. Fluids of transformed cultures contained heavy RNA similar to that of oncornaviruses. These findings suggest the presence of viral information in some human bone tumors.


Growth and responsiveness of human granulocytic leukemic cells in vitro.

Cells from patients with acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) can be grown and their properties analyzed in agar gel cultures. Levels of the glycoprotein regulator colony stimulating factor (CSF) were found to be elevated in 19-66% of plasmas tested from patients with various types of granulocytic leukemia, and the growth of AML and CML cells in vitro was observed to be dependent on, and responsive to, stimulation by CSF-containing material. In both diseases, the leukemic cells appear to be in a responsive state with respect to normal growth regulators, and potentially alterations in regulator levels may therefore be able to achieve sustained arrest of the growth of leukemic populations.


Proliferation and maturation of human leukemia cells in liquid culture.

Bone marrow from patients with acute myelogenous leukemia (AML), acute myelomonocytic leukemia (AMML), chronic myelogenous leukemia (CML), preleukemia, and from healthy volunteers was cultured using a recently developed liquid diffusion technique. Differential and viable cell counts and 3H-thymidine labeling indices were performed at intervals up to 30 days. Differentiation was assessed morphologically by light and electron microscopy, histochemically, and by functional tests for phagocytosis and the presence of surface receptors for IgG. Colony-stimulating activity (CSA) was assayed against normal human bone marrow by the agar colony technique. In acute leukemia cultures, viable cell counts usually fell within the normal range. However, most AML cells failed to demonstrate significant maturation in vitro, and did not produce detectable CSA. In AMML cultures, maturation was defective but some differentiated macrophages were observed and the cells produced high concentrations of CSA. Preleukemic cultures demonstrated normal growth but maturation was impaired as evidenced by a high percentage of immature cells during the first 7 days. CML cultures showed abnormally high growth capacity resulting in viable cell counts 2-3 times normal. In the chronic phase of CML, maturation was qualitatively normal and the cells produced CSA. With the onset of blast transformation, maturation became abnormal but growth remained high. These studies support a concept of AML as a primary defect in cellular maturation and of CML as a primary abnormality of proliferation. The production of CSA by neoplastic cells relates to the degree of monocyte-macrophage differentiation within the leukemic population. Human preleukemia is characterized by a failure of normal maturation in vitro.


Identification and characterization: cell membrane antigens associated with the blast phase of human adult leukemia.

Cell membrane antigens which produce delayed skin reactions and are associated with the blast phase of human acute leukemia have been identified and characterized. When patients are in remission, these proteins are not present on their white blood cells. The blast antigens associated with acute lymphatic leukemia (ALL) are also present on early human fetal thymus cells. Blast antigens from acute myelocytic leukemia (AML) appear to have a different structure and are not associated with fetal antigens. The isolation away from blocking factors of purified, solubilized proteins from the leukemic blast cell membranes now permits the possibility of testing to see whether or not such specific antigens will be useful in diagnosis and in immuno-chemotherapy of leukemia.


Immunotherapy for acute myelogenous leukemia.

One hundred and seven untreated patients with acute myelogenous leukemia (AML) were admitted to St. Bartholomew's Hospital between the 10th October 1970 and the 31st January 1973. Before receiving drugs to induce remission they were allocated alternatively into 2 groups to decide their remission treatment, a group to receive chemotherapy alone and a group to receive the same chemotherapy with immunotherapy. The patients were then given induction chemotherapy and 45 of them attained complete remission. All patients in remission then received chemotherapy consisting of 5 days treatment every 28 days. Patients receiving immunotherapy were also given multiple weekly intradermal injections of irradiated stored AML cells and Glaxo BCG using a Heaf gun. There were 19 patients in the group which received only chemotherapy during remission; 7 of these patients remain alive (median survival after attaining remission--303 days) and only 5 are still in their first remission (median remission length 188 days). Twenty three patients were allocated to receive immunotherapy during remission in addition to chemotherapy and 16 remain alive (median 545 days) and 8 are in their first remission (median 312 days). The difference in survival of the 2 groups is significant with a sigma value of 0.003.


[N,N-dimethyltryptamine: first comparative results. Preliminary communication].

On 7 male subjects (VP) the effect of 1.0--1.2 mg/kg N,N-dimethyltryptamine (DMT) s.c. on the acoustic evoked potentials (AEP) was studied; in 3 subjects simultaneously with the scalp EEG. The AEP were reduced 10 min after the application of DMT and returned at the 55th min. The on-off effect was diminished at the same time. Nevertheless, the VP recognized every click and tone and understood every word. d-LSD 25 (100 mug p.o.) showed no effect on AEP. The maximum of the psychopathological phenomena of DMT was shown about the 15th min. The maximum of the AEP suppressing effect was observed at the 30th min and coincided with the extrapyramidal signs of DMT effect. In cats (2 mg/kg DMT i.v.) AEP reacted in the same way. 2 mg/kg serotonin (5-HT) i.v. did not change the AEP in cats. I.v. DMT application 23 min later reduced the AEP only for a short period. It is discussed whether the antagonistic mechanism on peripheral substrates of 5-HT and DMT might be possible also on central synapses. In that case DMT might suppress inhibitory effects of 5-HT on receptors of the area postrema and---via feed-back---stimulate neurons of the ascending reticular system (hallucinogenic effects). The extinction of AEP and the reduction of on-off effect might be interpreted as a restoration of 5-HT effect with overcompensation and, therefore, with strong inhibitory interaction.


Inhibition of normal human in vitro colony forming cells by cells from leukaemic patients.

Co-culture in agar of normal bone marrow cells from different individuals gave granulocyte macrophage colony counts that were expected from counts made when the marrows were cultured separately. Co-culture of normal marrow with normal peripheral blood leucocytes (which did not themselves give rise to colonies) caused inhibition of colony growth only when the ratio of peripheral blood to bone marrow cells was of the order of 4 : 1. Peripheral blood or bone marrow cells from 7 of 9 patients with acute myelomonocytic leukaemia, which did not give rise to colonies, caused a marked reduction in the number of colonies obtained from normal marrow cells when cultured with them. This inhibitory effect of leukaemic cells was found when ratios of leukaemic to normal cells were as low as 1 : 4. Additional evidence that the inhibition of normal colony formation was related to the leukaemic process was obtained from follow-up studies on one of the patients whose cells lost the capacity to inhibit normal colony formation during remission and became inhibitory again on relapse.


Agglutination of peripheral blood lymphocytes from cancer patients and not from healthy controls, with the F2A1 histone fraction.

A simple, rapid histone agglutination test (HAT) is described. It consists of incubation in microplates or in microtubes of blood lymphocytes isolated from cancer patients and patients with non-malignant diseases with microquantities of histone fraction F2A1. Positive reaction is shown by massive agglutination of lymphocytes of the patients tested (126 subjects): this test was positive in 76% of cases. All controls (59 subjects) were negative.


The metastatic patterns of osteosarcoma.

The paper presents a detailed comparison of the anatomical distribution and frequency of clinically evident metastases in 152 cases of osteosarcoma, and autopsy findings in 43 cases. The behaviour of long bone tumours is contrasted with those arising elsewhere, which tend to metastasize less widely because of early death from effects of the primary tumour. In both clinical and autopsy series long bone tumours produced lung metastases (LM) in over 90% of patients dying with metastases, but the terminal frequency of extra-pulmonary metastases (EPM) rises from a clinical level of 33% to 83% at autopsy. There was little difference between tumours of the major long bones in the frequency of either LM or EPM, but EPM from the humerus tended to be fewer and sited above the diaphragm and from the femur below it. EPM most often involved other bones, notably vertebrae and pelvis. Not more than 10% of tumours invaded regional lymph nodes but terminally a quarter of the long bone tumours had metastasized to heart and abdomen. The infrequency of metastases in muscle was confirmed. The median time for LM was 5-6 months after starting treatment, for EPM 9-10. months. First metastases after 24 months were infrequent, especially in children. With delay in the appearance of metastases, whether LM or EPM, post-metastatic survival lengthened. Neither age, sex nor mode of treatment of the primary notably affected metastatic frequency, although recurrences were much more numerous when radiotherapy, even with high dosage, was the definitive treatment. Local recurrence usually appeared within 6-8 months and was shown to lead to increased frequency of osseous metastases. It is suggested that terminal dissemination may often be tertiary but not always from a pulmonary secondary.


Reactivation of scabies rash by methotrexate.

A 13-year-old female was on maintenance therapy for acute lymphoblastic leukemia. On three occasions she received methotrexate orally and each time this was associated with reactivation of scabies rash. The mechanisms for this phenomenon are discussed.


Biochemical studies in early infantile autism.

In four series of studies on schizophrenic patients and normals we found that all the schizophrenics eliminated N, N-dimethyltryptamines in their urine while none of the normals did so. Similarly, with early infantile autism (Studies I and II) and normal controls, this separation between patiens and normals still held. But ten parents of the five autistic children positive for bufotenin revealed that one or both parents, i.e.,  seven of ten were positive. The Psychiatric Assessment Interview, the Minnesota Multiphasic Personality Index, and the Rorschach indicated no significant evidence of psychopathology. Thus, individuals who revealed no psychopathology could still be positive for bufotenin. In studies III and V, 1 of 13 normals and 13 of 27 normals were positive, respectively. Study IV showed that 6 of 18 autistic children were positive for bufotenin.


Cytogenetic studies in a patient with acute granulocytic leukemia of seven and one-half years duration.

During a 7 1/2-yr period we monitored a chromosomally aberrant cell line in a woman with acute granulocytic leukemia (AGL) whose disease followed a rather unusual course. Her initial remission induced with 6-mercaptopurine (6-MP) and prednisone was maintained for 52 mo with biweekly doses of methotrexate (MTX) given orally. Because signs of liver dysfunction occurred, maintenance therapy was stopped. After 15 mo without chemotherapy, she suffered her first relapse (5 yr 7 mo after the initial diagnosis). A second remission, again induced with 6-MP and prednisone, was maintained for 1 yr, after which a second relapse occurred. Another remission lasting for only 4 mo was followed by a relapse of the leukemic process which led to her death. Cytogenetic studies of marrow cells and peripheral blood at the time of her initial diagnosis showed abnormal stem lines with characteristic chromosome markers. A small percentage of malignant cells bearing these markers persisted in her marrow during the years of her prolonged remission. At the time of her first relapse, 75% of her marrow cells had the marker karyotype, and at the time of her death (7 1/2 yr after the leukemia was diagnosed) all analyzable marrow metaphases had the characteristic chromosome changes.


Chromosomes and causation of human cancer and leukemia. XVI. Banding studies of chronic myelocytic leukemia, including five unusual Ph11 translocations.

Forty-two Ph1-positive cases of chronic myelocytic leukemia (CML) were examined with chromosomal banding techniques. Thirty-seven of these cases had the "standard" type of Ph1 translocation between chromosomes No. 9 and No. 22 [t(9;22)(q34;q11)] in the Ph1-positive marrow cells; 5 cases had unusual types of Ph1 translocation. Of the 37 cases, 21 had additional numerical and/or structural chromosomal changes, 2 had a missing Y chromosome, and 1 had an extra Ph1 in the Ph1-positive cells. In the 5 cases with unusual types of Ph1 translocation, chromosomes No. 2, No. 9 No. 10, and No. 13 were involved. The clinical picture in these 5 patients did not differ materially from that of the other Ph1-positive patients with CML, probably indicating that the recipient chromosome, with which the translocation from No. 22 takes place, does not play a crucial role in the course of the CML. In the 21 cases with abnormal karyotypes, nonrandom chromosomal changes were observed. Most of the changes were related to events occurring at the centromeric region. The prognosis of cases with only an extra No. 8 or Ph1 appears to be better than that for cases with an iso-17q [I(17a)] chromosome or other extra chromosomes. The presence of the Ph1 (delected No. 22) in every case points to the essentiality of this karyotypic findings in the diagnosis of CML and possibly in the genesis of the disease.


Combination chemotherapy for children with acute lymphocytic leukemia who fail to respond to standard remission-induction therapy.

Short courses of cytosine arabinoside (Ara-C), cyclophosphamide, and L-asparaginase were given to seven children with newly diagnosed acute lymphocytic leukemia, who had failed to remit on standard remission induction therapy. These 4-day courses of Ara-C and cyclophophamide followed by 4 days of L-asparaginase were repeated at 3- to 4-week intervals for two or four courses. Complete remission occurred in six patients. The median duration of remission was 94+ days, on various maintenance regimens. The most serious side effect was neutropenia. This combination of these three drugs appears to be effective remission-induction therapy for children with ALL with unfavorable prognostic features.


Adriamycin in the treatment of childhood acute leukemia. A Southwest Oncology Group study.

Sixty-six children with acute leukemia, in advanced stages of their disease and resistant to conventional chemotherapy, received adriamycin for remssion induction. Seventeen of 46 (37%) evaluable children with acute lymphocytic leukemia achieved a complete remission, and 5 (11%) achieved a partial remission. Two of 12 evaluable children with acute myelogenous leukemia achieved a complete remission, while an additional 3 achieved a partial remission. Two children with erythroleukemia also achieved a complete remission. Previous therapy with daunorubicin did not affect the response rate. The main toxicities observed with adriamycin were myelosuppression, fever, nausea and vomiting, stomatitis, alopecia, and cardiac toxicity (ST segment changes and arrhythmias).


Fine structure of a radiation-induced osteogenic sarcoma.

An osteogenic sarcoma arose in the right orbit of a 7-year-old boy some 5 years after the right orbit had been treated by four courses of radiotherapy (total dose approximately 13,000 rads) for a multicentric retinoblastoma. Death occurred 6 months after the orbital tumor was first detected. Study of the orbital tumor by electron microscopy revealed a cell population of varied morphology in which two main types were identified. In one group, the cells were large with radiolucent cytoplasm, which contained long branching segments of rough endoplasmic reticulum. In the second group, the cells were smaller with irregular nuclei and an electron-dense cytoplasm, which contained short segments of dilated rough endoplasmic reticulum and numerous mitochondria. The first group of cells closely resembled osteoblasts, while the second group had some features of osteoclasts or their percursors. The branching processes of the tumor cells were separated by an amorphous ground substance, which contained collagen-like fibrils and hydroxyapatite crystals. Crystal deposition was in some instances in close relation to extracellular membrane-bound vesicles.


Proliferative fasciitis.

The clinical and pathologic features of 53 cases of proliferative fasciitis, a pseudosarcomatous process involving fascia and interlobular fibrous septa of the subcutaneous fat, were reviewed. In the reviewed material, the lesion affected adults exclusively, with a high incidence in patients older than 40 years (median 54 years). It involved most commonly the upper and lower extremities, and microscopically was characterized by a diffuse infiltrative fibroblastic growth intimately associated with multifocal proliferation of large basophilic cells, closely resembling ganglion cells--a microscopic picture akin to proliferative myositis. In 16 of the 53 cases, the lesion had been initially confused with sarcoma because of its rapid growth and its bizarre histologic features. Although the term "proliferative fasciitis" has been used in the past as a symptom for nodular fasciitis, it is suggested that it be limited to the lesion under discussion, in order to emphasize its close relationship to proliferative myositis. Followup information revealed a benign clinical course. Therefore, despite its rapid growth and bizarre microscopic appearance, the lesion is adequately treated by local excision, and there is no indication for radical surgery.


Effect of mouth rinsing and toothbrushing with fluoride solutions on caries among Norwegian schoolchildren.

The caries experience and the plaque and gingival conditions of 14-year-old children participating in fortnightly fluoride (0.2 % NaF) mouth rinsing (88 subjects) were compared with observations in children performing supervised toothbrushing with a fluoride (0.5 % NaF) solution 4-5 times per year (n = 90). Most of the children, 84 and 90% respectively, had participated in these programs for the previous 6 years. Caries was assessed only on radiographs. The mean number of decayed surfaces was 5.8 (s.d. = 4.1, n = 88) and 5.4 (s.d. = 4.1, n = 90). The mean numbers of decayed and filled surfaces were 19.3 +/- 9.2 and 27.9 +/- 10.2 for subjects with rinsing or brushing. This significant difference could not be ascribed to sex, social class, years of residence in the towns, number of dentists performing the previous treatments, toothbrushing habits, use of fluorides at home, or amount of plaque. All children had gingivitis. There were no differences in the mean number of Plaque Index score 2 or the number of Gingival Index score 2 between the children with the different preventive programs. The girls' oral hygiene was better than the boys', but the gingival conditions were the same. Sex, social class, and toothbrushing techniques tended to have a slight influence on the amount of plaque.


Dental status and treatment needs among institutionalized mentally subnormal persons in Norway.

Dental status and treatment needs were studied in a random sample comprising 353 mentally subnormal persons. The sample was drawn to represent institutionalized mentally subnormal persons in Norway aged 5-45. The overall dental health was poor, primarily due to inadequate and fragmentary treatment facilities. Whereas the dental condition of children below 15 years of age was acceptable, as measured by the DMFT index, tooth loss increased rapidly with advancing age. Nearly every second dentulous person needed some conservation, and every tenth needed extraction of one or more teeth. One-third of the patients needed treatment requiring general anesthesia. It was concluded that a new system for the investigation of treatment requirements should be developed. This system must be based on diagnostic and social criteria, and should serve as a guideline for the plannning and delivery of dental services to the various subgroups of mentally subnormal persons.


The influence of examination of the assessment of the intra-examiner error by using the plaque and gingival index systems.

The plaque situation on 48 surfaces in 31 children 13 years of age was assessed. A re-examination within 2 hours indicated a significant increase in the number of O Plaque Index scores. Following paired comparison of each of the 48 areas, 22 % of the surfaces were found to have changed score. Significantly more scores indicating improvement of the plaque situation were found at the second examination. A re-examination of plaque on consecutive days in a similar group of children showed no significant changes. Re-examination of the gingival conditions within 2 hours indicated a significant increase in the number of scores of 2 and this was confirmed by the paired comparison on the 48 surfaces. The findings indicate systematic errors rather than intra-examiner inconsistency.


A field biopsy method for fluoride determinations in human surface enamel.

An enamel biopsy method was developed that is especially intended for use under primitive clinical conditions in field studies. Three successive enamel layers, each of 1 mum or less, were etched off the same delimited area of 3 mm2 by means of perchloric acid, using a microsampler with disposable tips. The biopsy technique was applicable to the vestibular surface of almost all teeth, causing no perceptible damage to the enamel surface. Based on cumulated data from the successive enamel layers, curves were drawn from which F levels at various depths in the outer 3 mum of the enamel could be interpolated. F levels in surface enamel of maxillary first premolars in 40 12-13-year-old children in a locale with 0.5 mg F/l in the drinking water were found to be 3,800, 2,400 and 2,000 parts/10(6) in three successive enamel layers of 0.6, 1.0 and 1.1 mum, respectively, demonstrating a decrease in F concentration of about 1,800 parts/10(6) within this depth interval. Identical F concentrations were found in bilateral premolars.


Some epidemiologic evidence on the etiology of caries.

While laboratory research has identified multiple causal factors in dental caries, few epidemiologic studies have been conducted on large representative populations that have utilized enough variables to test the current models of causation. Data from a large, representative study were available to the authors for secondary analysis. The epidemiology of dental caries as presented in the study indicates that the caries patterns in a free-living population were consistent with an infectious and nutrition model of causality. The genetic explanation, while represented in the data, was not as consistent with the findings as the infectious and nutritional explanations.


A longitudinal study of dental health in Swedish children aged 3-5 years.

This paper presents data concerning caries, gingivitis, interdental spacing, occlusion and oral habits obtained in a longitudinal investigation of 177 children at the ages of 3, 4 and 5 years. It was found that between 3 and 5 years of age, deft increased from 2.01 to 4.05 and defs from 2.69 to 5.98. The occlusal surfaces of the primary second molars and the occlusal and distal surfaces of the primary first molars were the ones most often affected. The mean Gingival Index decreased from 3 to 5 years (P less than 0.05) and also the number of children with a score of 2 from 4 to 5 years (P less than 0.05). The sagittal and transversal relationship between the jaws remained unchanged in most of the children, while the vertical relationship varied with changes in sucking habits. Dummy sucking was initially more than three times as common as finger sucking, but decreased markedly with increasing age. The children with the habit of finger sucking tended to keep this habit. Nocturnal grinding of the teeth was reported by the parents of 13 % of the children. Dental treatment was needed by 61 % at the age of 3, by 71 % at the age of 4 and by 68 % at the age of 5, as they had caries and/or gingivitis with a gingival score of 2. Futhermor, there was a need for orthodontic supervision including treatment. Caries prophylactic treatment was necessary in all age groups.


Dental caries in schoolchildren in some Danish communities with and without school dental service.

The purpose of the investigation was to compare the caries prevalence (DMF-T) among 762 7th grade children, of whom one-half had never received school dental care. The children were grouped according to social status in order to see if there was any difference in the caries prevalence between the social groups. The caries prevalence in children both with and without school dental service was high, 9.5 DMF-T and 10.5 DMF-T. The prevalence of untreated caries and secondary caries was lowest in the group with school dental service.


A method for defining the level of periodontal treatment need in a population of 15-year-old schoolchildren.

In a public dental service with scarce resources, the presence of gingivitis in teenage children cannot necessarily be considered as indicating treatment need. However, it is suggested that early bone loss may be an important indication for treatment in teenage children and the aim of the present study was to determine whether the presence of early bone loss in 622 15-year-old children assessed by the measurement of loss of attachment could be predicted from more readily identifiable factors such as gingival bleeding or subgingival calculus. However, such screening tests will make errors by including "healthy subjects" or excluding "diseased "subjects. The acceptable balance of these two kinds of error is a public health decision, a decision which may be affected by a number of variables, including the public's and profession's attitudes to the disease, the effectiveness of available treatments and the resources available.


[The surface of ceramics covered bridges].

The gingival surfaces of bridge bodies and routinely baked ceramic samples were examined under the microscope with top illumination, the scanning electron miscroscope, and by means of a surface testing device (caliper). The findings correspond more or less to the results found by other authors. Furthermore they confirm the clinically well-founded suspicion that the dull glow, which is preferred for esthetical reasons, does not provide a desirable surface quality. Therefore it is requested that the mucosal surfaces of the bridge bodies be glazed. The defective spots in the ceramic surface frequently found in the transitional area to the metal give rise to the recommendation that these regions should not be brought into contact with the gingiva and that the transitional zone between bridge body and bridge abutment should be prepared in line with hygienical considerations.


[Is the testing for changes in shape of denture base materials meaningful].

The results obtained in measurements of the dimensional behavior of U-shaped specimens correspond to the dimensional behavior of dentures. Part of the dimensional changes found in U-shaped specimens are not observed to the same extent in dentures, but produce interior tension in the denture. The bigger the dimensional changes in the U-shaped specimen, the bigger the dimensional changes in the denture or the tensions in its interior. Thus, the results of the measurements of U-shaped specimens demonstrate the behavior of a clinically used denture. Corresponding guidelines for testing purposes are proposed.


[Mechanical-dynamic properties of prosthesis plastics].

Comparative studies on the mechanic and molecular properties of heat- and self-curing polymers (PMMA) showed the following results: 1. The glass-transition temperature of heat- and self-curing polymers clearly shows measurable differences also as a function of their storage conditions. However, this is hardly of any clinical or practical significance. 2. The modulus of elasticity values of heat and self-curing polymers are not significantly different in the range of the usually applied temperatures. However, water-uptake considerably reduces the rigidity. 3. Overloading or fatigue failures do not show any clear differences in morphological characteristics. The practical influence of smaller long-term inflation strength of self-curing polymers has not yet been sufficiently proven. 4. Heat and self-curing polymers are identical as basic materials for dentures from the point of view of material technology.


[Reaction heat of elastomer casting materials. Preliminary report].

Cross-linking of elastomeric impression materials is an exothermic process. In addition to the frictional heat produced during mixing, the reaction heat may increase the temperature by several degrees Centigrade in thermically isolated samples.


[Methods and results of dental and prosthetic care following mandibular hemignathectomy].

By inserting auxiliary prosthetical means (anchored dental replacement with splinting elements) functional failures can be reduced. By using molding surfaces in the one-piece model cast denture the displaced mandibular stump is repositioned and the occlusal relationship between upper and lower teeth reconstructed largely without periodontal damage to the residual dentition.


[Evaluation and wearing habits of complete dentures--results from a patient questionnaire].

In a questionnaire answered by 578 patients with new total dentures the personal attitude of the patient to his dental replacement was tested. Ninety per cent of the patients considered their dentures to be good or satisfactory, while 10 per cent were not satisfied. In addition, findings regarding the length of time for and manner in which dentures are being worn as well as denture care and expectations concerning prosthetical treatment are reported.


[The functional loading capacity of total prostheses].

In 63 patients the loading capacity of total dentures was measured. The tests started with the day of insertion and covered up to 200 days. During this period of time changes in the loading capacity as a function of the measuring point were recorded and evaluated. The tests showed that with the exception of the incisors, the loading capacity is bigger after 200 days than when the denture is inserted and that the existence of denture sores and the base surface influence these values. However, patients' age and sex as well as the length of time for which an already existing denture had been worn do not seem to have any influence.


[Remounting of complete dentures].

A remounting method in which after polymerization, total dentures together with the original models are replaced into the articulator and are ground in there, does not produce the accuracy we are aiming at when determining the intermaxillary relation by means of registration with a central pin. On the patient it was demonstrated that grinding-in after intraoral registration of the finished mandibular and maxillary total dentures by means of the central pin registration, interlocking, and placement into the articulator produces more accurate results.


[Clinical results of the functional bite analysis. II. Co-determining factors for the therapeutic results].

In the present study the influences of type and duration of complaints, findings, therapeutic method, duration of therapy and patient cooperation on the prognosis of temporo-mandibular joint disorders were analyzed. The elimination of occlusal interferences may be regarded as causal therapy in the large majority of temporo-mandibular joint disorders. In these cases a very good and long-term rate of success may be achieved by the method of selectively grinding-in the teeth according to A. Lauritzen.


[Traumatic injury of a permanent tooth by forceps delivery (presentation of a case)].

A case of malformation of an upper central permanent incisor is described. From the history, it is assumed that the isolated malformation of the affected tooth, No. 21, may be due to indirect consequences of a birth trauma (forceps delivery). The problems of developing malformations connected with this case are discussed generally and specifically for a single tooth.


[Elementary electromyographic analysis and motion patterns of the myoglossus muscle].

In five fully dentulous and one edentulous patient, the m. myloglossus was examined by means of concentric needle electrodes and implanted wire electrodes. It was not possible to achieve absolute inertia with the conductors. The individual potentials of motoric units are bi- and triphasic. The duration was 3 to 5 msec, and the amplitude was 200 to 800 muvolt. The portion of polyphasic potentials is about 5%. With moderate innervation the discharge frequency is 2 to 8/sec. With maximum innervation, interference activity is observed. Kinetic studies showed that the m.myloglossus acts as typical antagonist in lateral tongue movements and as synergist when raising tongue and throat. From these findings conclusions may be drawn with regard to prosthetics.


[Percentual loss of active desmodontioum in horizontal tooth resorption].

Radicular surfaces connected with the bone by the periodontal membrane were measured by means of a galvanic method. The investigation showed that the surface reduction as a function of the length of the root cannot be compared with the surface reduction of a cone, since at least in the coronal quarter of the root, the percent decrease in surface is linear, especially in the case of teeth with several roots. The clinical significance of this investigation becomes evident when evaluating the bone destruction visible in a radiogram related to loading capacity. In the author's investigation an average loss of 60% was found.


[Evaluation of a teaching program as caries and periodontal prophylaxis].

Evaluation of the teaching program on caries and periodontal prophylaxis for students in the first preclinical semester in the dental school shows that after four evaluation steps with a total of 159 pro-bands the final test was answered to more than 80%, that it may be expected that about 65% of the knowledge is memorized after one and a half years, and that teaching a patient how to clean his teeth may be regarded as promising with the students having behaved correctly with regard to more than 70% of the most important criteria. Since the training program is independently worked through by the students, in addition to the other lectures, the continuing program may be based on the above mentioned values.


[Apex and periapical periodontium of teeth with endodontic-endosseal pin fixation].

Teeth with endodontic-endosteal pin fixation were observed for several years and radiolucencies that could be interpreted as chronic inflammation, were found in the periapical region of these teeth. The cause is sought in the iatrogenic noxa of the originally applied method. It is recommended to expose the apex of teeth to be provided with endodontic-endosteal pin fixation and to shorten the apex by grinding off 2-3 mm.


[Endodontic-endosseal fixation and capping pin].

For improving the endodontic-endosteal fixation method, an endodontic-endosteal fixing and capping pin was developed after six years of experience. Its form and adaptability to the widened root canal permits succesful fixation via the canal in a single session with only little technical means. At the same time the pin with its cap enables permanent anchorage of the crown.


[Management of the edentulous mandible with plate implants and prosthetic solution].

With exact indications and selection of patients, improvements may be achieved by implants especially in patients of specific professional groups. Blade implants with one or two posts are used, they are connected with each other by means of bars fastened by screws. The denture itself is fixed to the bars by means of a bolt.


[Clinical studies on fissure sealants of the Bis-GMA type].

In this study the effects of two fissure sealants were tested clinically, 50 teeth were sealed with Nuva Seal and 54 teeth with Epoxy-Lite 9075. Follow-ups were performed over a period of 15 months. In chi2 tests, a highly significant reduction in caries or restriction of caries was found in the sealed teeth as compared to the teeth of the control group.


[The damage caused by caustic acids during sealing of the dental enamel].

The chemical etching of enamel required for adhesion of sealant layers on the dental surfaces means that the enamel structure is weakened, especially due to the fact that after application of the sealant the cauterized layers are no longer in a remineralization equilibrium with the dental environment. The reactions on which cauterization is based are critically discussed. Newly developed synthetics are mentioned whose application as a sealant renders previous cauterization of the enamel by acids superfluous.


[The use of energy in casting and the viscosity of zinc oxide-eugenol pastes].

The recorded diagrams give information on the viscosity (consistency) at any given time. The force data indicate the difference in the viscosity (consistency). The line in the graph reflects the setting behavior. A flow test should be included in the specification of impression materials. The consistency test provided for in the ADA specification does not have any clinical significance, neither have changes in the load.


[Occlusal interferences in children (result of a study on 12 to 16 year olds].

Occlusal interferences entail painful muscular changes from the static as well as dynamic viewpoint. On the basis of this hypothesis, the causes for occlusal interferences were to be detected by means of clinical findings and model findings. In accordance with an earlier study by the author, the following main causes were found in 212 juveniles (98 without and 114 with orthodontic treatment) in the age of 12 to 15 years: occlusal interferences are dut to premature contacts and lacking disclusion. The juveniles were classified according to the type, causes, and consequences of their occlusal interferences. 178 juveniles had occlusal interferences and 34 had physiological occlusions.


[Radiation exposure of the dentist].

The radiation dosis per person undergoing dental treatment measured at the trunk is rather considerable, though not alarming. However, the number of people whose hands has been exposed to radiation as well as the individual extent of exposure were unexpectedly high. The radiation dosis measured at the hands was about 100 times bigger than the radiation dosis determined at the trunk for the whole body. Although these results may be very impressive, it should be borne in mind that the data on which the investigation was based date from 1967/68 and may no longer be fully applicable to the present situation. Whether and to what extent this assumption is justified ought to found out by control studies regarding radiation dosis per person and Röpak programs which are presently being started and whose results will be discussed in this journal.


[Objective radiological stereophotogrammetry in dentistry].

By means of objective radiological stereo-photogrammetry of two extraoral stereoscopic radiograms, the location of dislocated impacted teeth was determined preoperatively in a model. During operation it was possible to find the teeth at the computed position.


A survey of air and population lead levels in selected American communities.

The concentration of lead in the ambient atmosphere was determined at 59 sampling sites in eight American communities during the period 1968-71. Nineteen sampling sites had existed in a similar survey in 1961-62. At 14 of these sites the lead-in-air value was found to be higher in the current study than in 1961-62. The observed annual mean atmospheric concentration of lead varied from 0.14 mug/m3 (Los Alamos) to 4.55 mug/m3 (Downtown Los Angeles). Higher lead values were associated with urbanization. The concentration of lead in the blood of specific well-defined populations was determined. Such populations lived in geographic proximity to specific air sampling sites. In the three metropolitan areas from which both urban and suburban population groups had been obtained, the mean blood lead levels were significantly higher in the former. In two of the three areas the blood lead level was higher in urban smokers and non-smokers than in the corresponding suburban populations, classified by smoking habits. At each location the concentration of lead in the blood of smokers was greater than that in the blood of non-smokers. The magnitude of the observed urban-suburban difference (for populations comparable in smoking habits) ranged from 0.9 mug/100 gms to 4.5 mug/100 gms. It is probable that these observations partially reflect lead absorption from ambient atmospheres differing in lead concentration. There was no significant concordance between the ranking by site of mean air lead levels and that of the mean blood lead levels prevalent in the related populations. The observation that urban levels of blood lead and higher than suburban levels, but that air concentrations of lead are not clearly reflected in blood lead levels on a general national basis, suggests that factors other than the atmospheric lead level are of relatively greater importance in determining the blood lead levels in population groups. No relationship was established between age of participant and the blood lead level. In husband-wife pairs, presumably exposed to similar diets and atmospheres, the males had significantly higher blood lead levels than did the females. This difference could not be attributed to smoking habits or to hematocrit levels. The possibility that the difference was due to dissimilar quantities of foods in the respective diets of men and women was not examined. Studies of dietary lead levels showed them to be generally lower than commonly reported in the literature, 100 mug/day being a closer approximation in the population studies than the widely quoted 300 mug/day.


Tracer studies of ingestion of dust by urban children.

It has been known for many years that the eating of leaded paint is the prime cause of lead poisoning and elevated blood leads of children living in deteriorated housing. Recently, there has been speculation that children may eat dirt and dust contaminated with lead exhausted from cars and that this amount of ingested lead is sufficient to contribute significantly to the childhood lead problem. This study used a naturally occurring radioactive tracer (lead-210) to determine the relative amounts of dust and other lead-containing materials (e.g., paint) eaten by young children. This tracer is present in very low concentrations in paint and in significantly higher concentrations in fallout dust. Stable lead and lead-210 were analyzed in fecal material from 8 children suspected of having elevated body burdens of lead and 10 children living in good housing where lead poisoning is not a problem. The normal children averaged 4 micrograms lead per gram dry feces, with a range of 2 to 7. Of the eight children suspected of having elevated lead body burdens, two had fecal lead values within the normal range. However, the remaining six were 4 to 400 times higher. Despite these differences in fecal lead between the two groups, the groups were essentially identical in the lead-210 content of their feces. The "elevated" children averaged 0.040 picocurie lead-210 per gram dry feces, while the normal group averaged 0.044. The results provide sound evidence that these children suspected of elevated lead body burden were not ingesting dust or air-suspended particulate.


Biologic effects of airborne particulate lead on continuously exposed rats and rhesus monkeys.

The biological effects of airborne particulate lead were studied in rats and rhesus monkeys (Macaca mulatta) exposed nearly continuously (22 hours per day) at a concentration of 21.5 mug Pb/cubic meter of air. The year-long exposure elicited an increase in the concentration of lead in the blood to 28 mug/100 ml in the rats and 17 mug/100 ml in the monkeys. Levels of lead in control animals were about 5 mug/100 and 4 mug/100 ml, respectively, in the rats and monkeys. The elevated blood-lead levels reached a maximum during the first few months of exposure and did not increase significantly after that time. Elevated concentrations of lead were also detected in lung, liver, kidney and bone of both species. While concentrations of lead were nearly always less than 1 mug/g in control animals, they rose to 2-3 mug/g in soft tissues of exposed animals and up to 6 mug/g in bone. Differences between lead levels in animals exposed six months or twelve months were very small. The concentration of lead decreased in the soft tissues of animals removed from the chamber after one year's exposure but remained elevated in bone. The activity of the enzyme delta-amino-levulinic acid dehydrase (ALAD) in circulating erythrocytes was inhibited about 70% in rats exposed to the airborne lead. No reduction of the enzyme activity occurred in brain or liver tissue of either the rats or monkeys. Normal levels of ALAD in erythrocytes of the monkeys were too low to permit meaningful measurements. In spite of the reduced ALAD activity in rat erythrocytes, there was no concomitant alteration in the excretion of heme precursors. In all other respects, there appeared to be no deleterious effects on the animals from exposure to the airborne particulate lead. No changes were detected in serum chemistry or hematology nor were there any gross, microscopic or ultrastructural pathologic changes observed.


Clinical studies on men continuously exposed to airborne particulate lead.

Two experiments were conducted to determine the effects of low-level exposure to airborne lead particulates on humans. Male volunteers were exposed 23 hours per day for about 18 weeks to either 10.9 mug Pb/m3 or 3.2 mug Pb/m3 of air. The particulate matter consisted primarily of sub-micron sized particles of alpha lead dioxide. During exposure to 10.9 mug Pb/m3, the mean blood-lead level of the men increased to 37 mug/100 ml while the level in controls remained at about 15 mug/100 ml. Exposure to 3.2 mug Pb/m3 elicited an increase in blood-lead to about 27 mug/100 ml. In both cases, the blood-lead levels appeared to plateau after about three months of exposure and subsequent to that, no further increases were observed. About two months after the men left the exposure chamber, their blood-leads returned to near normal levels. Although urinary excretion of lead was always within the limits usually considered normal, there was a definite increase in urinary lead in the men exposed to 10.9 mug Pb/m3 and a somewhat smaller increase in the men exposed to 3.2 mug Pb/m3. The activity of delta-aminolevulinic acid dehydrase was reduced by about 50% in the erythrocytes of men exposed to 10.9 mug Pb/m3, but returned to normal after exposure was terminated. Practically no changes in the activity of the enzyme were noted in the men exposed to 3.2 mug Pb/m3. Exposure to either level of particulate lead did not cause measurable changes in the excretion of heme precursors nor were there any alterations of serum chemistry or hematology profiles in any of the men.


In vitro effect of lead in blood on the determination of delta-aminolevulinic acid dehydrase.

Whole blood, as withdrawn, from lead-exposed dogs was added in varying proportions, to whole blood, as withdrawn, from normal (non-exposed) dogs. The resultant red cell ALADP activities and lead concentrations of the mixtures were then determined. It was found that the resultant ALAD activities could be predicted on the basis of simple dilution of the blood with normal ALAD activity by the blood with severely reduced ALAD activity. The observed values for ALAD of the mixtures related to resultant lead concentration according to the equation: Y = a+ bx, rather than to the equation log y = a+ bx as reportedly observed for samples of blood from lead-exposed humans, and from lead-fed dogs. There was no evidence that the ALAD activity contributed by the portion of normal blood in the mixture was affected by the lead contributed by the blood from the lead exposed dog. This is considered as evidence that the reduction in red cell ALAD activity observed in lead-exposed dogs is not an in vitro artifact inherent in the method used to determined ALAD activity...


An epidemiologic approach to community air lead exposure using personal air samplers.

Accurate information on the relationship between blood lead and air lead is essential to any consideration of the possible effect of air lead on the body burden. Past studies of occupationally exposed workers have established that such a relationship exists at high levels of air lead exposure. No such information has been available for subjects exposed to the low air lead levels representative of present-day community exposure. Past studies in this area have suffered from inadequate information on actual lead exposure at the air lead levels of concern. Researchers have has to rely on air lead data obtained from stationary samp;ing stations. Because wide variations can exist betwween locations within a city such information could not be assumed to represent the exposure of any individual subject. At lbest they can be considered only approximations of actual exposures. The Naational Research Council recognized the deficiencies of past studies in their report "Airborne lead in perspective" and recommended that "more precise studies are needed of the relation between atmospheric lead in the urban environment and the concentration of lead in the blood, perphaps by the use of personal monitors". This paper describes the study which was undertaken to evaluate the effect of air lead exposure as measured with personal air sampling devices on indices of lead absorption such as blood lead, urine lead, DALA and ALAD activity...


Structural rearrangements associated with the Ph1 chromosome in chronic granulocytic leukaemia.

Four cases of C.G.L. in which banding of the Ph1 chromosome was performed were found to have variation from the usual 9/22 translocation pattern. All 4 cases showed a rearrangement involving at least 3 chromosomes, 2 of which were a9 and a22. One of these cases had in addition an XYY karyotype in the bone marrow.


Missing Y chromosome in juvenile chronic myelogenous leukemia.

A child with Ph1-negative juvenile chronic myelogenous leukemia (CML) is presented. The only chromosomal abnormality in hematopoietic tissues consisted of an absent Y chromosome. While a missing Y chromosome in adult patients with CML may be associated with a better prognosis, the clinical course in our patient was as malignant as that usually observed in other children with Ph1-negative juvenile CML.


Intermittent chemotherapy and immunotherapy with BCG in remission maintenance of children with acute lymphocytic leukemia: effects upon immunological function.

Twelve children with acute lymphocytic leukemia who had been in complete remission on continuous chemotherapy for at least 12 months, were treated with intermittent courses of chemotherapy alternating with BCG inoculation during the drug-free intervals. Measurements were made of leukocyte populations in blood and bone marrow leukemic blastogenic responses of blood lymphoid cells to phytohemmagglutinin and soluble leukemic blast cell membrane antigen. Antibody titers to a soluble leukemic blast-cell membrane-derived antigen were determined. Comparison was made with similar measurements during a second phase of intermittent chemotherapy without BCG inoculation (phase II). Two children showed bone-marrow relapse and two developed central nervous system leukemia during the study. Rises in blood and bone-marrow lymphoid cell numbers were found during both phases of the study. Blastogenic responses to phytohemagglutinin, depressed at the start of the study following at least 12 months of continuous chemotherapy, rose during intermittent chemotherapy and BCG and remained within normal ranges during phase II. Antibody titers and blastogenic responses to leukemia blast-cell membrane antigens increased in eight of twelve and six of seven children respectively during the BCG phase and were maintained during phase II. Only one child showed further increases in phase II. The combination of BCG and intermittent chemotherapy may increase leukemia-associated immunity in some patients with acute lymphocytic leukemia in remission. The separate contributions of either BCG or intermittent chemotherapy in producing this effect cannot be determined by this study.


Distinctive banded marker chromosomes of human tumor cell lines.

Nine human tumor cell lines (five breast carcinomas and four sarcomas) have been studied and each revealed groups of distinctive banded marker chromosomes which can serve to identify them and aid in monitoring cell line specificity. This was possible neither by conventional karyology in terms of numbers and morphology of chromosomes nor by glucose-6-phosphate-dehydrogenase mobility which was type B for all cultures. The significance of the clonal nature of the cell lines is discussed.


Effect of human lysozyme (muramidase) on potassium handling by the perfused rat kidney. A mechanism for renal damage in human monocytic leukaemia.

Purified human lysozyme (muramidase) stimulated potassium excretion by the isolated perfused rat kidney. Lysozyme is filtered and reabsorbed, without a tubular maximum. Over 90% of lysozyme filtered is retained within the kidney; 50% was recovered by enzymic assay and histologically localized to the proximal tubular cells. Hypokalaemia seen in some patients with myelomonocytic leukaemia may be directly attributed to an elevated circulating lysozyme level.


Influence of occlusal adjustment by grinding on gingivitis and mobility of traumatized teeth.

The effect on marginal inflammation and tooth mobility of occlusal adjustment by grinding was investigated in 43 occlusally traumatized teeth in 29 subjects with gingivitis and marginal periodontitis. The material consisted of 4 groups with tooth mobility of varying degrees of severity, and bone destruction. In all groups increased tooth mobility decreased subsequent to occlusal adjustment. The latter was without effect on the sulcus fluid flow rate or gingivitis scores in either gingivitis or periodontitis patients.


Periodontal treatment of multirooted teeth. Results after 5 years.

This paper describes: (1) a system for classification and treatment of furcation involvements, and (2) a 5-year post-operative evaluation of 100 patients treated for periodontal breakdown in the bi/tri-function areas. The results of this study demonstrate that it is possible to arrest further destruction within the root furcation area. The successful treatment of the multirooted teeth was probably the consequence of: (1) the quasi total elimination of plaque retention areas from the bi/tri-furcation area, and (2) meticulous oral hygiene by the patients.


Effect of chlorhexidine on dental plaque formation under periodontal pack.

In a first experiment, no appreciable differences in plaque formation under periodontal packs were observed in subjects rinsing with and without 0.2% chlorhexidine digluconate. In a second experiment, one gram periodontal packs were coated with 15 to 20 mg of chlorhexidine dihydrochloride powder prior to application and allowed to remain in situ for 4 days. Significantly less plaque formed under periodontal packs with chlorhexidine powder than with control packs. Chlorhexidine dihydrochloride powder may be recommended under periodontal packs for reduction of microbial plaque.


Effect of chlorhexidine on gingival wound healing in the dog. A histometric study.

Wound healing after gingivectomy was studied in five 1-year-old dogs (Beagles). During a preparatory period of 4 months, the teeth of the dogs were brushed twice a day using a toothbrush and dentifrice. At the end of this period, all gingival units appeared healthy. All mechanical tooth cleaning procedures were then terminated. Following a period a 2 weeks without oral hygiene, six gingival units, taken bilaterally from the maxillary first molar and posterior premolar areas, were subjected to standardized gingivectomies. Subsequently, the biopsied areas of the left half of the jaws were treated twice a day with a 0.2% aqueous solution of chlorhexidine digluconate for 42 days, while corresponding areas of the right jaws were given saline treatment. Tissue specimens were obtained after healing periods of 42, 28, 14, 7, 4 and 2 days. They were then immediately placed in a Karnovsky fixative, and afterwards decalcified in EDTA. The rate of tissue regeneration and degree of inflammatory cell infiltration were evaluated with histometric methods. It was found that while gingival wounds treated with saline regenerated with extensive inflammatory reactions, corresponding chlorhexidine-treated wounds healed with only minor signs of inflammation.


Common medical emergencies: a dilemma in dental education.

A four-week hospital-based program offers a comprehensive course for dental students in the evaluation and management of medical emergencies. The program first emphasizes medical evaluation with the taking of accurate, comprehensive patient histories and the performance of physical examinations; information about supportive care, including intravenous techniques and airway maintenance, is given. The diagnostic signs and treatment of common medical emergencies, as taught in the program, are described.


Carotid system arteritis: an overlooked and misdiagnosed syndrome.

Because of the broadened scope of dental practice, a thorough knowledge and understanding of head and neck pain is necessary to diagnose adequately and to treat the patient properly. The complexities of disease related to head and neck pain may mislead and confuse the diagnostician. Carotid system arteritis may be easily overlooked in everyday practice. Diseases with similar symptoms must be considered before rendering treatment. Although the mortality rate of arteritis is extremely low, the condition merits immediate recognition and treatment for relief of pain. The need to include head and neck arteritis in the differential diagnosis of orofacial-neck pain has been discussed and a treatment regimen with use of corticosteroids has been suggested.


Composition and structure of dental enamel: elemental composition and crystalline structure of dental enamel as they relate to its solubility.

The same elements, 21 in number, were found in both acid-resistant and acid-susceptible enamel specimens by ion microprobe analyses. However, there were differences in the concentrations of 14 elements between groups. Of the 16 trace elements found in enamel, the concentrations of K, F, and Na in parts per million were the greatest. Enamel surface analyses showed V and Zn were more concentrated in acid-resistant specimens by factors of 7.4 and 6.1 respectively, followed by nine other elements, the last molybdenum, that were just slightly more prevalent in acid-resistant enamel. Four elements were equally concentrated in both groups of samples, and only one trace element, B, was more abundant in the acid-susceptible samples by a factor of ten. Ca and P were predominantly more abundant in acid-resistant speciems, and C, H, and O were more concentrated in acid-susceptible samples. The enamel substance in acid-resistant and acid-susceptible groups was found to be similar by these methods. --Ion microprobe: the same elements were detected in both groups. Four trace elements (titanium, lead, Cl, and lithium) were equally abundant in the two groups. --Electron diffraction: the crystal structure type was the same in both groups of samples. --Infrared absorption: the crystalline substance showed the same spectra in both groups. The enamel substance in the two groups of specimens was found to be dissimilar by these methods. --Ion microprobe: the concentrations of 11 trace elements as well as Ca and P were greater in acid-resistant enamel. The concentrations of C, H, O, and B were greater in acid-susceptible enamel. --X-ray diffraction: crystallites in the acid-resistant specimens were larger by a factor of more than two. Enamel solubility appears not to be related to atomic species but associated with one, some, or all elements quantitatively and also with its physical form (crystallite size and probably density).


Treatment of temporomandibular joint syndrome with biofeedback training.

Treatment of temporomandibular joint syndrome by the use of biofeedback training involves two stages. First, the patient is made aware of the level of tension in the masseter muscle and, second, he is taught to reduce the level of tension. In those individuals whose pain most likely is associated with high muscle tension, this treatment method is apparently successful. The successful treatment of a patient with a history of long-term TMJ pain is described.


Prevalence and localization of Streptococcus mutans in infants and children.

The prevalence and localization of Streptococcus mutans in the oral cavities of 92 children was investigated. The ages of the children ranged from newborns to 5 years. The edentulous newborns and infants with only their deciduous incisors did not harbor S mutans on the mucous membranes or the smooth surfaces of the incisors. As the number of erupted deciduous teeth increased, there was a gradual increase in the isolation of the organism. The greatest isolation frequency of S mutans, 46.3%, occurred in those children with a complete deciduous dentition and contact between the deciduous molars. The interproximal areas where there was molar contact were the most frequent sites of early colonization of S mutans.


Status report on silver amalgam. Council on Dental Materials and Devices.

This report discusses the current status of amalgam. The new alloy systems have been reviewed in relation to their advantages, disadvantages, and clinical use. Values for the physical properties of amalgam have increased tremendously in the past 50 years and relatively recent changes in alloy composition, size, and shape of particles can produce clinically observable improvements in restorations, particularly with respect to marginal integrity. New alloys that are now available or are very close to being introduced on the market should be investigated and observed by practitioners. However, it should be recognized that correct alloy manipulation of currently available alloys probably has more influence on the longevity of restorations than the type of alloy selected.


Observations on the epidemiology of Rift Valley fever in Kenya.

The epizootic range of Rift Valley fever in Kenya is defined from the results of virus isolations during epizootics, and form an extensive serological survey of cattle which were exposed during an epizootic. A study of the sera from a wide range of wild bovidae sampled immediately after the epizootic, showed that they did not act as reservoir or amplifying hosts for RVF. Virus isolation attempts from a variety of rodents proved negative. Rift Valley fever did not persist between epizootics by producing symptomless abortions in cattle in areas within its epizootic range. A sentinel herd sampled annually after an epizootic in 1968 revealed not one single seroconversion from 1969 to 1974. Certain forest and forest edge situations were postulated as enzootic for Rift Valley fever, and a small percentage of seroconversions were detected in cattle in these areas, born four years after the last epizootic. This has been the only evidence for the persistence of the virus in Kenya since 1968, and may be a part of the interepizootic maintenance cycle for Rift Valley fever in Kenya, which otherwise remains unknown.


Observations on the epidemiology of ephemeral fever in Kenya.

Ephemeral fever antibody was found in domestic cattle in Kenya across a wide range of ecological zones, from highland forests and grasslands to desert and semidesert thorn scrub. Antibody was found in several species of game animals, notably waterbuck and buffalo, where over 50% of the samples showed antibody to EF. Evidence was obtained to show that the virus had been cycling in these wild ruminant populations between epizootics in domestic cattle.


The differential transmissibility of Myxoma virus strains of differing virulence grades by the rabbit flea Spilopsyllus cuniculi (Dale).

Laboratory studies showed that few rabbit fleas (Spilopsyllus cuniculi (Dale)) transmitted myxomatosis after removal from wild rabbits (Oryctolagus cuniculus (L) that had been infected for fever than 10-12 days, irrespective of the virulence of the myxoma virus strain involved. Rabbits infected with fully virulent (Grade I) strains died within 10-15 days and few fleas from these hosts became infective; averaging all the samples takem. 12% of the fleas were infective. Also, few fleas acquired infectivity on individual rabbits which covered from infection with attenuated strains; the mean was 8% infective. Rabbits which died between 17 and 44 days after infection had higher proportions of infective fleas at all sampling times; the mean was 42% infective. Male and female fleas transmitted virus with equal efficiency. For rabbits infected with any of the attenuated virus strains the mean percentage of infective fleas was inversely related to the survival time of the host. Rabbits infected with moderately attenuated strains (Grades IIIA and IIIB) had, on average, the highest proportion of infective fleas; hence such strains have a selective advantage and have become predominant under natural conditions in Britain. The changes that might occur if there is an increase in host resistance to myxomatosis are discussed.


Multiple skin testing of Kenyan schoolchildren with a series of new tuberculins.

This study on Kenyan schoolchildren aims to elucidate the effect of contact with environmental mycobacteria on the development of specific delayed hypersensitivity. A series of 12 skin test reagents was employed; eleven of them were prepared from extracts of living mycobacteria and the last was the P.P.D. RT 23. Eight of the new tuberculins were prepared from mycobacteria recovered from the East African environment. A total of 8641 tests were carried out on 4320 children between the ages of 6 and 17 years in four townships. Two of these townships were in fertile agricultural areas and two were in the desert. Just over 80% of the children had received BCG immunization The results obtained showed that increasing age, geographical locality and BCG immunization all had a profound effect, and socioeconomic background had some effect, on the pattern of reactivity to the various reagents. The rationale behind the use of the series of new tuberculins and the results obtained with them are discussed in relation to the interacting effects of the factors complicating these results.


[Studies on the effects of dental amalgam upon the fertilization and early development of sea urchin eggs (Hemicentrotus pulcherrimus) (author's transl)].

Silver-tin amalgam that has been used as a filling material in routine dental clinic contains a large amount of mercury and the cytotoxity of metal mercury may hazard to patients. There have been a number of papers reporting that the dental amalgam has not any toxic action to living cells in animal experiments in vivo. However, the mechanism of cytotoxic action and effects of these metals for tissues and cells were not reported so far. In the present experiments, the analysis of the cytotoxic action of silver-tin alloys and their amalgam in vitro cytological experiments with fertilized eggs and developing embryos of sea urchin, Hemicentrotus pulcherrimus, were examined. When the silver-tin alloy powder was incubated in normal sea water medium there are non or weak cytotoxic reaction upon fertilized eggs and early embryos of sea urchin. Metal mercury in the medium effects remarkable cytotoxic action upon the development of early embryos; the cleavage and early development were delayed and all of the embryos show deformity. Immediately after the alloy powder was triturated with mercury, it shows strong cytotoxic action as the metal mercury was incubated, however, the cytotoxic action decreased and almost disappeared in 5 hours after trituration. The mechanism of cytotoxic action and the adequacy of clinical application of the amalgam were discussed.


[Elastic modulus of dental porcelains by dynamic method (author's transl)].

Using an equipment with sensitive vibretor-controller oscillater of elactrostatic drive system, we sought for the difference between elastic modulus of various kinds of dental porcelain and elastic modulus by firing method. We examined the relation between temperature of firing and elastic modulus as well. The obtained results are as follows: 1). Elastic modulus of low fusing porcelain of enamel color was 4.32 times 10(11) dyn/cm2 by air firing 3.95 approximately 4.63 times 10(11) dyn/cm2 by vacuum firing. Low fusing of porcelain of dentin color and the one of enamel color had the same elastic modulus. 2). Elastic modulas of high fusing porcelain of enamel color was 3.58 times 10(11) dyn/cm2 by air firing, 3.41 approximately 3.64 times 10(11) dyn/cm2 by vacuum firing. High fusing porcelain of dentin color and the one of enamel color were of the same elastic modulus. 3). Porcelain of opaque color for metal bond was 3.22 times 10(11) dyn/cm2 by air firing 3.97 approximately 4.22 times 10(11) dyn/cm2 by vacuum firing. When dentin color was added to opaque color elastic modulus was low (3.90 times 10(11) dyn/cm2). 4). Alumina porcelain of opaque color was 5.42 times 10(11) dyn/cm2 by air firing, 6.50 approximately 6.80 times 10(11) dyn/cm2 by vacuum firing. When dentin color was added to opaque color elastic modulus was very low (3.90 times 10(11) dyn/cm2). 5). Elastic modulus to various kinds porcelain changes according to temprature of fusing. And the highest elastic modulus is at the temperature which is 50 approximately 100 degrees C lower than final firing temperature.


[Study on the age-hardenable silver alloy (3 rd report). III. On the ageing process of dental Ag-Pd-Cu-Au alloy (author's transl)].

The precipitation hardening process of a dental silver base alloy, Ag-28 Pd-10 Cu-12 wt % Au, was studied by means of X-ray diffraction, hardness measurement and metallographic observations. After solution treatment at 900 degrees C for 30 min, specimens were subjected to anisothermal annealing at the rate of 1 degrees C/min. PdCu ordered phase and alpha2 solid solution (Ag rich phase) precipitated hetelogeneously at the grain boundaries and then grew up into each grain. Drastic increase in hardness was recognized with the spread of nodular region. Electron microscopic observation of these precipitates showed very fine lamellar structure. It is concluded that the age hardening of this alloy could be attributed to this grain boundary precipitation and the softening at the overaged stage to the second grain boundary reaction which produced very coarse lamellar structure.


[Studies on the dental gold-alloys (13). Precipitation hardening in gold-cobalt alloys (author's transl)].

The precipitation of cobalt from gold-rich solid solution was studied about Au-Co binary alloys containing less than 5 wt.% cobalt by correlating the results of metallographic observation and micro-hardness measurement to electrical resistivity measurements. The hardness curves of the alloys showed to hardness peaks after isothermal ageing below a certain temperature. It was considered that the first peak was due to formation of G. P. zone which was confirmed by reversion phenomenon. The second peak was due to growing of metastable cobalt rich precipitate. The maximum hardness obtained by ageing was higher in Au-5 wt.% Co alloy than in Au-1 wt.% Co alloy. Difference in growing mechanism of metastable precipitate was deduced from the kinetics data and the values of time exponent obtained by Johnson-Mehl equation.


[Studies on the dental gold-alloys (14). Effect of platinum addition on the AuCu-transformation by means of x-ray diffraction analysis (author's transl)].

X-ray diffraction studies were carried out so as to investigate the effects of 0.33-6.90 at. % additions of platinum on the ordering process of AuCu alloy. The stable existing temperature range of AuCu I was extended to higher temperature by the addition of platinum to stoichiometric gold-copper alloy, the ordering rate in these alloys were slower than that of binary AuCu. Changes in diffraction patterns showed a different sequence in ordering process at higher and lower temperature range. Orthorhombic AuCu II was only found in the alloy containing 0.33 at.% Pt at around 410 degrees C.


[Studies on the dental methacrylic resins (part 4). Flow properties and curing times of the pour methacrylic resins (author's transl)].

Flow properties and curing times of the pour resins consisted of polymethyl methacrylate and methyl methacrylate were investigated by the viscosity and the temperature measurements. The polymers with various article sizes and molecular weights and the monomer with 0.005 per cent hydroquinone were used the pour resins respectively. The initiator system of benzoyl peroxide--N, N-dimethyl-p-toluidine was used for the polymerization. The results were as follows: 1) The viscosities of the pour resins were increased with the time elapsed. That was for reasons of physical phenomenon, that is, dissolution of polymer into monomer. The logarithmic viscosities increased linearly in proportion to the time elapsed. 2) The viscosities of the pour resins were increased by the reduction of the particle size of the polymer and by the increase of the molecular weight of the polymer. 3) The curing times of the pour resins were reduced by the increase of the concentrations of benzoyl peroxide and N, N-dimethyl-p-toluidine, and by the reduction of the particle size and the molecular weight of the polymer respectively.


[A study on the cytotoxic action of gold-copper alloy by means of tissue culture (author's transl)].

Nine kinds of gold-copper alloy containing copper of various contents, such as 91% Au-9% Cu, 83% Au-17% Cu, 75% Au-25% Cu, 58% Au-42% Cu, 50% Au-50% Cu, 25% Au-75% Cu, 20% Au-80% Cu, 15% Au-85% Cu, 10% Au-90% Cu and two pure metals of copper and gold, were used to analyse cytotoxic action of gold-copper alloy. A cytotoxicity of these alloys and metals was observed by replicate culture using L-strain cells. The results obtained, were as follows; When the range of copper content was from 0 to 42%, the alloys showed no cytotoxic reaction. There was, however, strong cytotoxic action in the gold-copper alloys containing copper of 50% or more.