Caries and Its Association with Infant Feeding and Oral Health-related Behavior in 18-month and 3-year-old Japanese Children

The primary aim of this study was to determine the prevalence of dental caries and its association with infant feeding and oral health-related behavior in Japanese children between the ages of 18 months and 3 years. A total of 387 infants were initially examined at the age of 18 months (or 19 months in some cases) and then again at 3 years (or at 3 years 1 month in some cases). The primary objective was to identify factors contributing to the prevalence of caries in children aged 18 months. The secondary objective was to follow up children with no caries at the age of 18 months to seek potential correlations between background factors and the increment of caries by the age of 3 years. In an adjusted multivariate logistic regression model, children who continued breastfeeding were approximately 7 times more likely to have dental caries at 18 months of age than those who did not. Infants brought in for an oral examination and consultation at around 12 months of age were less likely to develop dental caries at 18 months of age than those who were not. Multivariate logistic regression analysis revealed that infants who did not receive a dental check-up at 12 months of age showed a significantly higher incidence of dental caries at 3 years of age. The present results suggest that prolonged breastfeeding is a risk factor for early childhood caries at 18 months of age, and that infants in whom a regular oral care program is implemented from the age of 12 months are less likely to develop early childhood caries at 18 months or 3 years.

Development of Jaw and Deciduous Teeth in Japanese Children -Comparing Size of Crown and Alveolar Area between Today and 40 Years Ago

The purpose of the present study was to investigate change in the size of the jaw and deciduous teeth in Japanese children over the past 40 years by performing measurements on plaster models of the dental arch obtained from children born between 2007 and 2009 (2000s group) and children born between 1968 and 1974 (70s) group. A total of 61 children were enrolled in the 2000s group, comprising 25 boys (average age, 4 years 5 months) and 36 girls (average age, 4 years 4 months), and 93 children in the 70s group, comprising 45 boys (4 years 6 months) and 48 girls (4 years 4 months). The mesiodistal width of the crown, dental arch width, dental arch length, dental arch height, and available arch length in these groups were measured using a 3D measurement system and the sums of the mesiodistal width of the crown and tooth size-arch length discrepancies calculated. The results of the two groups were statistically compared and the following conclusions reached: the size of deciduous teeth has not changed statistically over the last 40 years; the size of the dental arch has decreased in boys (p<0.01), while remaining approximately the same in girls; and the tooth size-arch length discrepancy has decreased, especially in boys (p<0.01). These results indicate that the interdental spaces of the deciduous dentition have decreased, increasing the risk of crowding in Japanese children.

Unstable rocker shoes promote recovery from marathon-induced muscle damage in novice runners

We recently reported that wearing unstable rocker shoes (Masai Barefoot Technology: MBT) may enhance recovery from marathon race-induced fatigue. However, this earlier study only utilized a questionnaire. In this study, we evaluated MBT utilizing objective physiological measures of recovery from marathon-induced muscle damages. Twenty-five university student novice runners were divided into two groups. After running a full marathon, one group wore MBT shoes (MBT group), and the control group (CON) wore ordinary shoes daily for 1 week following the race. We measured maximal isometric joint torque, muscle hardness (real time tissue elastography of the strain ratio) in the lower limb muscles before, immediately after, and 1, 3, and 8 days following the marathon. We calculated the magnitude of recovery by observing the difference in each value between the first measurement and the latter measurements. Results showed that isometric torques in knee flexion recovered at the first day after the race in the MBT group while it did not recover even at the eighth day in the CON group. Muscle hardness in the gastrocnemius and vastus lateralis showed enhanced recovery in the MBT group in comparison with the CON group. Also for muscle hardness in the tibialis anterior and biceps femoris, the timing of recovery was delayed in the CON group. In conclusion, wearing MBT shoes enhanced recovery in lower leg and thigh muscles from muscle damage induced by marathon running.

Alveolar Growth in Japanese Infants : A Comparison between Now and 40 Years ago

To investigate differences in alveolar growth during the primary dentition period among different age groups, dental arch width, length, and height were measured in 93 dental arch plaster models obtained from 4-year-olds born between 1968 and 1974, 88 from 5-year-olds born between 1968 and 1974 (70s group), 61 from 4-year-olds born between 2007 and 2009, and 56 from 5-year-olds born between 2006 and 2008 (2000s group). A comparison was also performed to determine whether there was any difference in change between 4 and 5 years of age. The results showed age- and sex-dependent differences in growth patterns in primary dental arch width, length, and height. The amount of change was greater in the 2000s group than in the 70s group, suggesting that yearly growth between 4 and 5 years of age has increased over the last 40 years.

Longitudinal investigation of relationship between developmental changes in sagittal occlusion and caries in lower first permanent molars

The aim of the present study was to investigate the relationship between developmental changes in sagittal occlusion and the presence of caries on the occlusal surface of the lower first permanent molars. Dental casts were taken from 60 children at 2-monthly dental examinations after the emergence of the lower first molars through to when they reached 22 years of age. Data on the state of the occlusal surfaces of 120 lower first permanent molars were collected from these examinations and each occlusal surface classified into one of the following two categories: (1) sound, or (2) caries (filled). Sagittal occlusion of the first permanent molars was classified as Angle Class I, II, or III at each developmental stage. The data were analyzed to assess the relationship between changes in the occlusal characteristics and the presence of caries (fillings) in the lower first permanent molars. Of a total of 120 lower first permanent molars, 36 (30.0%) were filled by the end of the study period. Occlusal caries attacks occurred most commonly between 24 and 72 months after emergence of first permanent molars. New occlusal caries continued to occur thereafter, however, even though the teeth had already erupted for as long as 14 and 16 years. A Class II occlusal relationships in the lower permanent molars throughout the study period showed a significantly stronger correlation with caries than when it changed from Class II to Class I. With a Class II occlusal relationship, the percentage of teeth with fillings showed a continual increase, even though those teeth had already been erupted for between 10 and 16 years by the end of the study. These results suggest that occlusal sealing is still indicated for 3 or more years after eruption when the lower first permanent molars occlude in a Class II relationship as their risk for caries remains relatively high.

Effects of different combinations of fused primary teeth on eruption of the permanent successors

PURPOSE

The fusion of primary teeth may be associated with the absence of 1 of the 2 permanent successors. Moreover, even if both successors erupt, developmental disturbances such as microdontia or delayed tooth formation may occur. The purpose of this study was to elucidate the effects of different combinations of fused primary teeth on the eruption of permanent successors.

METHODS

One hundred ninety-seven children with 247 fused primary teeth were examined. Combinations of primary teeth involved in the fusion were identified, and the effects of these different combinations on the presence, morphology, and eruption of the permanent successors were determined.

RESULTS

Three types of fusion in the primary teeth were identified: (1) between the maxillary central and lateral incisors (UCI/LI); (2) between the mandibular central and lateral incisors (LCI/LI); and (3) between the mandibular lateral incisor and canine (LLI/C). The results revealed an absence of the successional lateral incisor in 65% of UCI/LI cases and 74% of LLI/C cases, whereas only 16% of LCI/LI cases resulted in a missing successor.

CONCLUSIONS

Fused primary teeth are highly correlated with the absence of permanent teeth, and the prevalence depends on the combination of fused primary teeth.

Structure and expression of integrated hepatitis B virus genes in an HBs antigen producing human cell line (huGK-14)

A human continuous cell line (huGK-14) within a lineage of passaged cultures was investigated in the mode of integration and expression of hepatitis B virus (HBV) genes. HBV DNA was integrated in eight different sites of the cellular DNA, in each of which HBV genome was rearranged, fragmented, and/or partly deleted. Complete HBV genome that may lead to production of infectious virus particles was not detected in the cells nor in the culture medium. Clones of cDNA containing a complete coding frame for small HBs antigen protein (type adr) were obtained from mRNA of the cells. The cells were stable over the period of six months of cultivation and more than 60 population doublings in the mode of HBV integration and HBs mRNA expression.These results provide substantial evidence for the absence of an ability for the integrated DNA to create an infectious product in the cell; for the stable production of HBs mRNA from the cells, and suggest the usefulness of this cell line as a substrate for HBV vaccine production.

Glial fibrillary acidic protein mutations in adult-onset Alexander disease: clinical features observed in 12 Japanese patients

OBJECTIVE

To clarify the clinical manifestations of adult-onset Alexander disease (AOAD) in Japanese patients with glial fibrillary acidic protein (GFAP) gene mutations.

METHODS AND MATERIALS

  Twelve patients of AOAD with GFAP mutations detected in our centre were examined for neurological and magnetic resonance imaging (MRI) findings.

RESULTS

  Major symptoms were pyramidal and bulbar signs. In addition, three patients presented abnormal behaviour and/or memory disturbance. Two of the three patients also had Parkinsonism and had been diagnosed with fronto-temporal dementia or progressive supranuclear palsy until GFAP mutations were detected. Abnormalities of the medulla oblongata and cervical spinal cord were observed on MRI in all patients.

CONCLUSIONS

  Patients presenting with pyramidal and/or bulbar signs with abnormalities of the medulla oblongata and cervical spinal cord on MRI should be considered for GFAP analysis as this is the typical presentation of AOAD. Abnormal behaviour and cognitive disorders including deterioration of memory were rare symptoms but could be an obstacle to diagnosing Alexander disease.

Longitudinal study on influence of prolonged non-nutritive sucking habits on dental caries in Japanese children from 1.5 to 3 years of age

The purpose of the present study was to investigate the relationship between infant sucking habits and the prevalence of caries in Japanese preschool children.The study was designed as a prospective, longitudinal study starting with 592 children aged 18 months. Information on sucking habits and patterns of feeding was collected from parents in the form of a questionnaire. Children who continued breastor bottle-feeding at 18 months of age were eliminated prior to the evaluations. The children were divided into 3 groups according to their sucking habits at 18 months of age: Group 1: children with a finger-sucking habit (n=151); Group 2: children who used a pacifier (n=45) and Group 3: children with no oral habit (n=205). Clinical examinations were carried out by one of the authors.Mean dft and prevalence of caries were not statistically significant among the 3 groups at 18 months of age. However, only 10.6% of the children in Group 1 exhibited caries at 36 months of age, compared with 17.1% in Group 3 and 24.4% in Group 2. Group 1 children showed the smallest mean dft at 0.30 among the 3 groups at 36 months of age, and those in Group 2 showed 1.18; the difference was statistically significant (p<0.01).The results suggest that children with a finger-sucking habit are more likely to be free of caries by the age of 3. However, use of pacifier at 18 months of age is a potential risk factor for the development of dental caries in children.

The relation between tooth shape ratio and incisor arrangement in Japanese children

To investigate whether the relationship between tooth shape ratio and incisor arrangement proposed by Peck et al. in 1972 was applicable to Japanese children, we compared two groups, one with normal permanent dentition and another with crowded permanent dentition, using chronologically constructed plaster dentition models. Tooth shape ratio was obtained by dividing the incisor mesio-distal width by the labio-lingual width and then multiplying the result by 100. The results revealed a significant difference in the coronal mesio-distal diameter of the incisors between the two groups, but the other items showed no significant differences, suggesting no clear relationship between tooth shape ratio and incisor arrangement. That was, our results suggest that there is no clear relationship between tooth shape ratio of the mandibular incisors and arrangement of the permanent incisors in Japanese children.

Longitudinal Study of Prolonged Breast- or Bottle-feeding on Dental Caries in Japanese Children

The aim of this investigation was to study the effects of prolonged breast- or bottle-feeding on dental caries in Japanese infants. This longitudinal study was conducted by means of a questionnaire and clinical examination of 592 children at 18 months, 2 years and 3 years of age. The children were divided into three groups: 1) children still being breast-fed at 18 months of age (n=42); 2) children still being bottle-fed at 18 months of age (n=45); and 3) children weaned off of breast- or bottle-feeding and with no nonnutritive-sucking habits at 18 months of age (n=205). Results showed that breast-feeding at 18 months of age produced many significant differences to the control children, including a higher prevalence of caries and higher number of dft. However, no significant differences were observed between bottle-fed and control children. In conclusion, our results suggest that prolonged breast-feeding at an early age before primary dentition has fully erupted is a risk factor for dental caries. Therefore, breast-fed children need to be monitored more closely, and aggressive methods of preventive care need to be instituted. It is also important to identify factors related to dental caries among breastfed children as soon as possible, and develop effective preventive programs.

Characteristics of Breast-fed Children with Nursing Caries

The aim of this study was to investigate the characteristics and risk factors of prolonged breast-feeding in children. A total of 105 children aged 18 months were screened for ongoing breast-feeding at a public health center. Of these, 105 children were selected for a more comprehensive examination, involving investigation of dietary, tooth-brushing habits and oral hygiene. The children were examined again, and initial and manifest caries were recorded at 24 months of age. As a result, 20 (19.0%) of the 105 children had caries at 24 months of age. Logistic regression analysis revealed an association between caries and bedtime breast-feeding (p=0.003). Oral hygiene at 18 months of age was also correlated with caries (p=0.015). It was concluded that reducing the frequency of feeding, early establishment of good oral hygiene habits and also regular visits to the dentist are essential in preventing nursing caries in prolonged breast-fed children.

Effects of nonnutritive sucking habits on occlusal characteristics in the mixed dentition

PURPOSE

Little is known about the extent to which nonnutritive sucking habits contribute to malocclusion in the mixed dentition. The purpose of this study was to report on the relationship between certain occlusal traits in the mixed dentition and longitudinal sucking behaviors.

METHODS

Dental examinations were conducted on 630 children in the mixed dentition who participated in a large, ongoing longitudinal study. Five hundred eighty consented to impressions, and 524 adequate study models were obtained. Of these, 444 also had adequate longitudinal nonnutritive sucking data obtained via mailed questionnaires to parents at 3- to 6-month intervals from birth to 8 years. Sucking behaviors were grouped by predominant type and duration. Study models were hand articulated using wax bites to evaluate the occlusion for the presence of open bite, crossbite, molar relationship, and excessive overjet. Bivariate statistical analyses related presence of these malocclusions to sucking duration and type.

RESULTS

Fifty-five percent of the children had malocclusions (anterior open bite, posterior crossbite, bilateral Class II molar relationship, or overjet >4 mm). Class II molar relationship was most common (30%). Overall, anterior open bite and posterior crossbite was associated with habits of 36 months or more. Sustained pacifier habits, including those of 24 to 47 months, were associated with anterior open bite and Class II molar relationships, while digit habits were associated with anterior open bite when sustained for 60 months or longer.

CONCLUSIONS

Malocclusions are quite prevalent in the mixed dentition, and anterior open bite and posterior crossbite may be preventable by modifying nonnutritive sucking behaviors.

Tooth size-arch length relationships in the deciduous dentition: a comparison between contemporary and historical samples

In a recent study, it was reported that maxillary and mandibular arch lengths were significantly shorter in a sample of contemporary children in the deciduous dentition compared with a historical sample from about 50 years earlier. The purpose of this study was to describe secular changes that might have occurred in tooth sizes and tooth size-arch length relationships in the same cohorts of contemporary and historical North American white children in the deciduous dentition. The 2 samples were similar in terms of geographic location, racial and ethnic backgrounds, and socioeconomic status. Both samples were restricted to white children with a normal overjet (<4 mm) and a normal anteroposterior molar relationship, no anterior open bite, and no crossbite. In addition, subjects were excluded if any permanent teeth were erupted. Measurements of mesiodistal tooth sizes and arch lengths of maxillary and mandibular arches were made, and tooth size-arch length discrepancies (TSALD) were determined. The results indicated that tooth sizes were generally similar in the 2 cohorts but slightly larger in contemporary children. Crowding, as measured by TSALD, was found to be common in the mandibular arch for contemporary children in the deciduous dentition of both boys and girls. Moreover, crowding was much more common and severe in contemporary children compared with children in the historical cohort. Further research is needed to determine whether the increase in mandibular crowding in the deciduous dentition will continue to be observed in the mixed and permanent dentitions and to further establish these possible secular trends.

Interdental spacing and caries in the primary dentition

PURPOSE

This study assessed the relationship between interdental spacing patterns and caries experience in the primary dentition.

METHODS

Caries examinations were conducted amoung 356 children 4 to 6 years of age. At the time of the examinations, alginate impressions were obtained and poured in yellow stone. From the stone casts, each interdental area was categorized as: (1) space > 1 mm, (2) space < 1 mm, (3) no space, teeth in contact, or (4) no space, teeth overlapped. These categories were collapsed into presence or absence of space for each interdental site, and counted for each individual. Analyses assessed the relationships between interdental spacing and caries experience with separate analyses for anterior spacing, posterior spacing and total spacing.

RESULTS

Children with more total interdental spaces had less decay experience and less untreated decay than children with fewer interdental spaces, and children with more molar spacing had less molar decay experience; however, these relationships were weak. Correlation analyses demonstrated significant relationships between number of decayed surfaces and total number of interdental spaces (r=-0.11, P=.04) and number of molar sites with interdental spaces (r=-0.13, P=.02). Multivariate analyses revealed the total number of interproximal spaces to be weakly associated with interproximal caries experience, but that fluoride exposure was a much stronger predictor.

CONCLUSIONS

Absence of interdental spaces is weakly associated with greater decay experience in the primary dentition.

Tooth wear patterns in the deciduous dentition

Tooth wear is common in the deciduous dentition. A recent study suggests that tooth wear in the deciduous dentition is related to subsequent tooth wear in adults, so that early identification of factors related to tooth wear could be of long-term benefit. The purposes of this study were to describe patterns of tooth wear in the deciduous dentition and to relate tooth wear to occlusal characteristics and longitudinal dietary patterns. Data were collected as part of a longitudinal study of a cohort of children recruited at birth from Iowa hospitals. Stone casts were obtained in the deciduous dentition stage, and 355 children, 4 to 5 years old, met the selection criteria. Tooth wear was categorized for each tooth as none, mild, moderate, or severe, and related to occlusal characteristics and longitudinal data on fruit juice and soft drink consumption. All children exhibited some tooth wear on at least 1 tooth, and nearly 16% of them had at least 1 tooth with severe wear. Tooth wear was generally more severe in the maxillary arch and the anterior teeth. Severe tooth wear on the molars was significantly related to posterior crossbites, but severe tooth wear on the incisors was related to Class III canine relationships. There were no statistically significant relationships between tooth wear and soft drink or fruit juice consumption. Based on our results, we concluded that mild tooth wear is universal in the deciduous dentition, but only a few occlusal factors are related to severe tooth wear. Tooth wear was not related to any dietary patterns we investigated.

Effects of oral habits' duration on dental characteristics in the primary dentition

BACKGROUND

Studies dating to the 1870s have demonstrated that long-term nonnutritive sucking habits may lead to occlusal abnormalities, including open bite and posterior crossbite. However, little is known as to whether habits of shorter durations have lasting effects.

METHODS

The authors collected longitudinal data on nonnutritive sucking among children through a series of questionnaires regularly completed by parents. Researchers examined the children at ages 4 to 5 years and obtained study models. The models were measured for dental arch parameters (including arch width, arch length and arch depth) and assessed for overjet, overbite and posterior crossbite. The authors compared the dental arch and occlusal conditions among groups of children with nonnutritive sucking habits of different durations.

RESULTS

Children with nonnutritive sucking habits that continued to 48 months of age or beyond demonstrated many significant differences from children with habits of shorter durations: narrower maxillary arch widths, greater overjet and greater prevalence of open bite and posterior crossbite. In addition, compared with those who ceased their habit by 12 months of age, those with habits at 36 months of age had significantly greater mandibular canine arch widths, maxillary canine arch depths and overjet, while those with habits at 24 months and 36 months had significantly smaller palatal depths. Prevalence of anterior open bite, posterior crossbite and excessive overjet (> 4 millimeters) increased with duration of habits.

CONCLUSIONS

While continuous nonnutritive sucking habits of 48 months or longer produced the greatest changes in dental arch and occlusal characteristics, children with shorter sucking durations also had detectable differences from those with minimal habit durations.

CLINICAL IMPLICATIONS

It may be prudent to revisit suggestions that sucking habits continued to as late as 5 to 8 years of age are of little concern.

The fusion of three primary incisors: report of case

The occurrence of a fusion of three primary incisors is rare. A two-year-old Japanese girl was brought to the pediatric dental outpatient clinic, Tokyo Dental College, to receive a caries-prevention treatment. The fused tooth consisted of the maxillary primary central incisors and right maxillary lateral incisor. Primary left lateral incisor erupted normally and the other primary teeth were erupted. The radicular pulp chambers were fused into one for three fourths of the length from the apex, and only one root. The hair and skin of the patient appeared normal and no systemic abnormality or congenital disease was noted in the medical history of the patient and her family. The occurrence of a three-tooth fusion, and no supernumerary tooth was confirmed.

The horizontally impacted maxillary canine situated in a labial position

Surgical management of unerupted teeth depends upon a thorough understanding of anatomic, physiologic and pathologic factors. Attention has been given to problems of eruption in the maxillary anterior region. It is a region where a variety of anomalies occur. Since the maxillary anterior region influences appearance so greatly, early detection of difficulties and careful planning and treatment can be extremely beneficial to patients. The purpose of this case report is to present a case of maxillary permanent canine impaction in a horizontal displacement that developed after loss of the deciduous canine to chronic apical periodontitis, and incomplete root resorption of the deciduous canine.

Caries development in children from 1.5 to 3 years of age: a longitudinal study

This study was designed as a prospective clinical caries prevalence study starting with children at 1.5 years of age. The subjects were 374 children who were born between 1989 and 1991. All subjects visited a public health center in Kunitachi-city, Tokyo, at 1.5 years, 2 years, and 3 years of age. All the children and parents have followed preventive dental care guidance. Dental caries were always examined by one of the authors. The caries prevalences at 1.5 years, 2 years, and 3 years of age were 6.1%, 14.7%, and 31.8%, respectively. The mean dft at 3 years of age in children who developed caries before 2 years of age was significantly greater than that in children caries free at 2 years of age. The findings from the current study showed that children who develop caries before 2 years of age are at greater risk for dental caries.

Occlusal migration of the maxillary first primary molars subsequent to the loss of antagonists

The purpose of this study was to observe the vertical changes in unopposed maxillary first primary molars longitudinally. The subjects of this study were 17 children whose lower first primary molars had to be extracted. Space closure were prevented by crown-loop space maintainers for all these children. Plaster casts were made every 4 months for 16 to 24 months after the extraction. These series of casts were standardized, and vertical changes of the maxillary first primary molars against the occlusal plane were measured using a micro-reader. The mean changes indicated that maxillary first primary molars without intercuspidation tend to drift toward the extraction space. On the control side with antagonists, the maxillary first molars seemed to move reversed to apical throughout the observation period. Accordingly, the results of this study showed new trends after the premature loss of primary molars. The vertical changes toward extraction space varied from -0.40 mm to 1.43 mm at the 16 months after extraction. Mean changes were small, but there were some individual differences in reaction, giving negative values. However, we should always be concerned about loss of arch length and also occlusal drift of unopposed teeth, because the vertical changes were greater than 1 mm at 16 months after extraction in some cases.

Prevalence of congenital dental anomalies of the deciduous dentition in Japanese children

We examined the prevalence of anomalies in deciduous dentition in 2,733 Japanese three-year-old children. The results showed that fused teeth occurs in 4.10%, congenital missing teeth in 2.38%, enamel hypoplasia in 1.50%, peg-shaped teeth in 0.55%, palatal cusps in upper deciduous incisors in 0.37%, supernumerary teeth in 0.07%, and color anomalies in 0.07%. Sixty-nine boys and 43 girls had fused teeth, percentages of 4.88 and 3.26, respectively. This difference was significant. All the fused teeth were located in the anterior region and were more frequent in the mandibular than in the maxillary arch. In the mandibular arch, 50 cases involved the lateral incisor and canine; the central incisor and lateral incisor were fused in 48 instances. There were 30 boys (2.12%) and 35 girls (2.65%) with congenitally missing deciduous teeth. This difference was not significant. Unilateral missing teeth were more frequently observed than bilateral missing ones. The lower lateral deciduous incisor was the most frequently missing tooth. The prevalences of fused teeth and congenital missing teeth were significantly higher in this study than in studies of American and Scandinavian children. These two anomalies are tending to increase in frequency in Japan.

Promotion of cell growth and macromolecular synthesis in HeLa cells by insulin and low density lipoprotein: analyses at an early stage after change to K(+)-depleted medium

Stimulations of cell growth and macromolecular synthesis of HeLa cells by insulin and low density lipoprotein (LDL) were studied in relation to the effect of intracellular K+. After replacement of the culture medium by a chemically defined medium (K-CDM), addition of insulin plus LDL stimulated their growth. Protein synthesis was fast for the first 18 hrs. and then slowed to a constant rate with or without these agents. DNA synthesis began to increase from 15 hrs., attaining a maximum at 18 hrs. After change from K-CDM to CDM containing RbCl (Rb-CDM), Rb+ replaced about 80% of the intracellular K+ in 2 hrs. Cell growth in Rb-CDM was very slow but was markedly enhanced by insulin plus LDL. No initially rapid protein synthesis was observed. DNA synthesis decreased with time, but addition of insulin plus LDL resulted in transient increase. Thus, the initial rapid protein synthesis in K-CDM may be a prerequisite for inducing DNA synthesis that stimulates subsequent cell growth. In Rb-CDM, insulin plus LDL stimulated cell growth by increasing DNA synthesis without changing the synthesis of bulk protein, implying that they induced synthesis of growth-related proteins.

Structural organization of the gene encoding apolipoprotein A-II in an amyloidotic strain of senescence-accelerated mouse

An inherited polymorphism occurring in the murine apolipoprotein A-II (ApoA-II) transcript seems to be related to the senile amyloidosis which occurs in accelerated-senescence-prone mice (SAM-P). Such being the case, we have determined the entire nucleotide (nt) sequence of the apoA-II gene. The length of the gene is about 1.3 kb and it is interrupted by three introns and the four exons aligned perfectly with the previously sequenced elements of an apoA-II cDNA. Two-nt substitutions [Pro-5(CCA)----Gln(CAG)] in the SAM-P genome were identified in the third exon, hence, we could use a restriction fragment length polymorphism to detect the apoA-II molecular type. Several possible regulatory signals were identified (i) in the 5'-flanking region, including CAAT and TATA boxes, the viral enhancer-like sequence, and the consensus sequences of estrogen response element, and (ii) in the 3'-flanking region, including sequences conserved in the immunoglobulin enhancer, glucocorticoid and estrogen response elements, and a B1 repetitive sequence.

Structural analysis of phospho-D-mannan-protein complexes isolated from yeast and mold form cells of Candida albicans NIH A-207 serotype A strain

The immunochemical properties between phospho-D-mannan-protein complexes of yeast (Y) and mycelial (M) forms of Candida albicans NIH A-207 (serotype A) strain were compared. Hydrolysis of the Y-form complex gave a mixture of beta-(1----2)-linked D-mannooligosaccharides consisting mainly of tri- and tetra-ose, whereas the M-form complex gave preponderantly D-mannose. The antiserum against Y-form cells exhibited a lower reactivity with the M-form than with the Y-form complex, whereas the antiserum to M-form cells could not distinguish significantly between both complexes. Moreover, these acid-modified complexes showed lower antibody-precipitating effect than each corresponding intact complex against antisera of Y- and M-form cells. Digestion of the acid-modified Y- and M-form complexes with the Arthrobacter GJM-1 strain alpha-D-mannosidase yielded 35- and 40-% degradation products, respectively. Acetolysis of each modified complex under mild conditions gave the same D-mannohexaose, beta-D-Manp-(1----2)-beta-D-Manp-(1----2)-alpha-D-Manp -(1----2)-alpha-D-Manp- (1----2)-alpha-D-Manp-(1----2)-D-Man. Because the complexes of Y- and M-form cells of C. albicans NIH B-792 (serotype B) strain did not give any hexaose fraction containing beta-(1----2) linkages, the presence of this hexaose can be regarded as one of the dominant characteristics of the serotype-A specificity of C. albicans spp.

Metabolism of senile amyloid precursor and amyloidogenesis. Age-related acceleration of apolipoprotein A-II clearance in the senescence accelerated mouse

Serum clearance kinetics of murine senile amyloid-related high-density lipoprotein (HDL) apoprotein A-II (apo A-II) was examined in the senescence-accelerated mouse, prone (SAM-P/1) and resistant (SAM-R/1), with 125I-HDL purified from both strains. In SAM-R/1, with 125I-HDL purified from both strains. In SAM-R/1, the serum half-life of apo A-II was not altered with increasing age and was practically identical to that of apo A-I. In 2-month old SAM-P/1, the serum half-life of both apo A-I and apo A-II was generally the same as observed in SAM-R/1. However, at age 6 and 12 months, in SAM-P/1, the serum half-life of apo A-II decreased significantly and was less than that of apo A-I. These age-related changes in apo A-II clearance kinetics were observed regardless of the HDL donor. The authors also examined the tissue distribution of injected apo A-II, using 125I-apo A-II reconstituted HDL, and found that several organs trapped more 125I radioactivity in old SAM-P/1 than in young mice. This evidence strongly suggests that age-related changes in the metabolic environment of apo A-II might affect senile amyloidogenesis in SAM-P/1.

Structural study of phosphomannan-protein complex of Citeromyces matritensis containing beta-1,2 linkage. Application of partial acid degradation and acetolysis techniques under mild conditions

The phosphomannan-protein complex of Citeromyces matritensis IFO 0651 strain was investigated for its chemical structure by a sequential degradation procedure, partial acid degradation followed by acetolysis under mild conditions. Upon treatment with 10 mM HCl at 100 degrees C for 1 h, this complex released mannotriose and mannotetraose consisting solely of 1,2-linked beta-D-mannopyranosyl residues, ca. 20% on weight basis of the parent complex. The acid-degraded complex was then subjected to acetolysis using an acetolysis medium of low sulfuric acid concentration, a 100:100:1 (v/v) mixture of acetic anhydride, acetic acid, and sulfuric acid at 40 degrees C for 36 h. A phosphate-containing manno-oligosaccharide fraction eluted in the void-volume region of a Bio-Gel P-2 column was found to consist of Manp beta 1----2Manp beta 1----2Manp alpha 1----2Man to which 1 mol of phosphate group was attached, while a manno-oligosaccharide fraction eluted in the diffusable region was a mixture of Manp beta 1----2Manp beta 1----2Manp beta 1----2Manp alpha 1----2Man, Manp beta 1----2Manp beta 1----2Manp alpha 1----2Man, Manp beta 1----2Manp alpha 1----2Man, Manp alpha 1----2Man, and mannose in the molar ratio of 0.08:0.33:0.19:0.32:1.00. Therefore, the structural analysis of the polysaccharide moiety of a beta-1,2 linkage-containing phosphomannan-protein complex of fungal origin can be achieved by means of a sequential degradation procedure, partial acid degradation followed by acetolysis under mild conditions.

A molecular-pathologic approach to murine senile amyloidosis. Serum precursor-apolipoprotein A-II variant (Pro5----Gln) presents only in the senile amyloidosis-prone SAM-P/1 and SAM-P/2 mice

Murine apolipoprotein (apo) A-II is a serum precursor of murine senile amyloid protein. We determined the primary structures of apo A-II in accelerated senescence-prone mice (SAM-P) characterized by a high frequency of age-associated systemic amyloidosis and accelerated senescence-resistance mice (SAM-R) in which senile amyloidosis occurred with a low incidence. Apo-A-II variant (Pro5----Gln) was found to be present only in the serum of SAM-P and not in that of SAM-R or other random bred slc:ICR mice. The apo A-II variant in the serum of SAM-P is identical to the murine senile amyloid fibril protein (ASSAM) derived from amyloid-deposited tissues of SAM-P. These findings proved that apo A-II deposits in tissues without degradation and this mutation (Pro5----Gln) probably have significant effects on the structure and function of apo A-II and would play a critical role in murine senile amyloidogenesis.

Age-related changes in bone mass in the senescence-accelerated mouse (SAM). SAM-R/3 and SAM-P/6 as new murine models for senile osteoporosis

Age-related changes of the femoral bone mass in several strains of the senescence-accelerated mouse (SAM) were investigated. Microdensitometrically, all strains exhibited essentially the same patterns of age changes, that is, bone mass corrected by the diameter of the shaft reached the peak value when the mice were 4 or 5 months of age and then fell linearly with age up to over 20 months of age. Two strains, SAM-R/3 and SAM-P/6, which originated from the same ancestry on pedigree, had a significantly lower peak bone mass than other strains (SAM-R/1, SAM-R/2, SAM-P/1, and SAM-P/2). On the other hand, the strains with a low peak bone mass had the same rate of decrease as other strains. Mineral and collagen contents per dry weight of bone showed little difference among the strains. Histologic studies of tibia, femur, and lumbar spine revealed that the osteopenia was not due to osteomalacia but, rather, to osteoporosis. The elderly mice in these two strains were prone to fracture, thus should be important models for study of senile osteoporosis seen clinically.

The single proline-glutamine substitution at position 5 enhances the potency of amyloid fibril formation of murine apo A-II

The primary structure of murine apolipoprotein A-II (apo A-II) has been determined. Apo A-II consists of a single polypeptide chain of 78 amino acid residues, of which the amino-terminus is pyrrolidone carboxylic acid. Except for residues 5 and 38, the amino acid sequence is identical to that of murine senile amyloid protein (ASSAM), which has a common antigenicity with apo A-II. Substitution of glutamine (ASSAM) for proline (apo A-II) at position 5 is distinct and may possibly be related to murine senile amyloid-ogenesis.

Effects of nystatin on intracellular contents and membrane transport of alkali cations, and cell volume in HeLa cells

Nystatin (50 micrograms/ml) had strong influence on the intracellular contents and membrane transports of monovalent ions and water in HeLa cells. The nystatin-induced changes in the intracellular ion content and cell volume were inhibited by sucrose, and Donnan and osmotic equilibria were attained. Using cells under conditions for these equilibria, the concentrations of intracellular impermeant solutes, their mean valence, the differences of their intra- and extracellular osmotic concentrations, and the circumferential tension of the cell membrane were determined. Stimulation by nystatin of the influx of one cation species, e.g. Rb, was inhibited by another cation species, e.g. Na. The stimulatory effect of nystatin on cation fluxes was reversible within 1 hr after ionophore addition, and after 1-hr treatment the intracellular contents of Na and K became proportional to their extracellular concentrations, provided that the sum of these concentrations was constant (300 mM). Similar proportionality was also observed in the presence of choline, provided that the choline concentration was less than those of the alkali cations. The implications of these results in relation to the osmotic properties of cultured cells, and the experimental regulation of alkali cations in the cells, are discussed.

Purification and characterization of a senile amyloid-related antigenic substance (apoSASSAM) from mouse serum. apoSASSAM is an apoA-II apolipoprotein of mouse high density lipoproteins

Two putative serum precursors which cross-react with antiserum against murine senile amyloid protein (ASSAM) were isolated from the high density lipoprotein (HDL) of normal mouse serum. Apolipoproteins designated "apoSASSAM-1" and "apoSASSAM-2" have the same molecular weight as tissue amyloid fibril protein. ApoSASSAM-1 and apoSASSAM-2 migrate to an intermediate position between apoA-I and apoC on alkaline-urea polyacrylamide gel electrophoresis and are present mainly in HDL apoproteins and to a slight extent in very low density lipoprotein apoproteins when compared to apoC. ApoSASSAM-1 and apoSASSAM-2 are polymorphic; there are two apparent isoproteins of apoSASSAM-1 with isoelectric points of 4.72 and 4.79 and two major isoproteins of apo-SASSAM-2. Subunit bands of ASSAM separated by alkaline-urea polyacrylamide gel electrophoresis and that migrated to the same positions as apoSASSAM-1 and apoSASSAM-2 were labeled by anti-apoSASSAM-1 antiserum. The amino acid compositions of apoSASSAM-1 and apoSASSAM-2 were much the same and closely resembled those of ASSAM and mouse apoA-II. Sequence analysis of apoSASSAM and ASSAM revealed a blocked amino terminus. ApoSASSAM is considered to be a mouse apoA-II and probably transforms to amyloid fibril "ASSAM" in tissues through a process yet to be clarified.

High homology is present in the primary structures between murine senile amyloid protein (ASSAM) and human apolipoprotein A-II

The primary structure of a murine senile amyloid protein (ASSAM) was determined. The protein consists of a single polypeptide chain of 78 amino acid residues. The amino-terminus is blocked with pyrrolidone-carboxylic acid. The sequence differs from that of the known murine amyloid A protein and is highly homologous to human apolipoprotein (apo) A-II. The result indicates that the putative precursor of the senile amyloid protein is apo A-II in mice.

Kinetic mechanism of Na+, K+, Cl--cotransport as studied by Rb+ influx into HeLa cells: effects of extracellular monovalent ions

Ouabain-insensitive, furosemide-sensitive Rb+ influx (JRb) into HeLa cells was examined as functions of the extracellular Rb+, Na+ and Cl- concentrations. Rate equations and kinetic parameters, including the apparent maximum JRb, the apparent values of Km for the three ions and the apparent Ki for K+, were derived. Results suggested that one unit molecule of this transport system has one Na+, one K+ and two Cl- sites with different affinities, one of the Cl- sites related with binding of Na+, and the other with binding of K+(Rb+). A 1:1 stoichiometry was demonstrated between ouabain-insensitive, furosemide-sensitive influxes of 22Na+ and Rb+, and a 1:2 stoichiometry between those of Rb+ and 36Cl-. The influx of either one of these ions was inhibited in the absence of any one of the other two ions. Monovalent anions such as nitrate, acetate, thiocyanate and lactate as substitutes for Cl- inhibited ouabain-insensitive Rb+ influx, whereas sulfamate and probably also gluconate did not inhibit JRb. From the present results, a general model and a specialized cotransport model were proposed: In HeLa cells, one Na+ and one Cl- bind concurrently to their sites and then one K+(Rb+) and another Cl- bind concurrently. After completion of ion bindings Na+, K+(Rb+) and Cl- in a ratio of 1:1:2 show synchronous transmembrane movements.

Morphologic demonstration of cytoplasmic ASSAM-related antigenic substance (CASSAM) by an immunoperoxidase technique

Murine senile amyloid protein identified in the senescence-accelerated mouse (SAM) was called ASSAM, and the ASSAM-related antigenic substance was detected in the cytoplasm of hepatocytes, columnar epithelia of the small intestine, and epithelia of the proximal convoluted tubules of the kidney, with the use of an immunoperoxidase method. This substance, called CASSAM (cytoplasmic ASSAM-related antigenic substance), did not stain positively with Congo red nor fibril structure, as determined under an electron microscope. As the ASSAM (senile amyloid) deposition increased with advancing age, CASSAM observed in hepatocytes and columnar epithelia decreased both in SAM-P and SAM-R strains. In the liver of the SAM-P strain in particular, the incidence and intensity in deposition of ASSAM increased rapidly from 5 months of age; on the other hand, CASSAM observed in the hepatocytes decreased rapidly at about the same time. Cycloheximide-treated animals showed a significantly low concentration of SASSAM (serum ASSAM-related antigenic substance) and also a low incidence and intensity of CASSAM observed in the cytoplasm of the hepatocytes and epithelia of the small intestine. In colchicine-treated animals, SASSAM concentration was slightly lower, and the severity of CASSAM observed in the cytoplasm was slightly higher, in the liver and kidney, as compared with control values. CASSAM is assumed to be synthesized in the cytoplasm of the cell and to be secreted alone or in the lipoprotein form into the serum. This CASSAM or lipoprotein including CASSAM is perhaps a constituent of SASSAM (CASSAM is assumed to include apoSASSAM) and the hepatocytes and intestinal mucosal epithelia are possible production sites of apoSASSAM.

Chronic food restriction modulates the advance of senescence in the senescence accelerated mouse (SAM)

The effects of chronic food restriction on grading scores of senescence, deposition of senile amyloid (ASSAM), mean life span and 10th decile were investigated by using animal models for accelerated senescence (SAM-P/1) and for normal aging (SAM-R/1). The experimental groups consisted of control (ad libitum fed), 80% (fed 80% of control intake), and 60% (fed 60% of control intake) groups. The grading score of SAM-P/1 mice was significantly improved in the 60% group, but not in the 80% group, compared to the control group. The grading score of SAM-R/1 mice, however, was significantly less than that in the control group in both the 60 and 80% groups. In SAM-P/1 mice liver, skin and testis, the severity of senile amyloid deposition was significantly less with 40% food restriction (60% group) than in the control group. A restriction of 20% (80% group) had no influence on amyloid deposition. A definite tendency to prolong mean life span (24.3%) and 10th decile (65.9%, mean life span of the last 10th of survivors of a group) was observed in the 60% group of SAM-P/1 mice, but the changes were not statistically significant. In the 80% group of SAM-P/1 mice and also in either restriction group of SAM-R/1 mice, however, such a tendency was not evident. These results indicate that 40% food restriction modulates the advance of senescence in these mice.

Age-related changes of serum apoprotein SASSAM, apoprotein A-I and low-density lipoprotein levels in senescence accelerated mouse (SAM)

Age-related changes of serum concentration of apo SASSAM, an apoprotein of high density lipoprotein (HDL) which cross-reacts with antiserum against murine senile amyloid fibril protein (ASSAM) were estimated in senescence accelerated mouse (SAM-P) and in senescence resistant series (SAM-R), as a control, using a single radial immunodiffusion technique. Serum concentrations of apo A-I, a major apoprotein of HDL, and low density lipoprotein (LDL) were also measured. In SAM-P (SAM-P/1 and SAM-P/2) with a high incidence of senile systemic amyloidosis, we observed age-associated decreases in serum apo SASSAM levels. The concentrations of apo SASSAM at 16 months of age were below 40% of the concentration at 2 months of age, regardless of the sex. In contrast with SAM-P, we observed no age-associated decrease of serum apo SASSAM levels in SAM-R (SAM-R/1 and SAM-R/2) with a low incidence of amyloidosis. Serum apo SASSAM concentration was higher in SAM-R/1 than in any other strain of mice observed. Serum apo A-I concentration was highly and significantly correlated with the serum concentration of apo SASSAM and decreased with advancing age in SAM-P but not in SAM-R. Age-related changes of LDL were not observed in any strain, but the concentration was lower in the females. In old SAM-P (16 months' old), the concentration of apo SASSAM decreased to one-third of that in the young SAM-P (4 months' old) and the serum concentrations of albumin and total protein did not decrease, compared with those in the young mice. All these findings taken together suggest that abnormality of metabolism in apo SASSAM, putative precursor of ASSAM, might occur in SAM-P.