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Biomedical subjects

A Mo

Publications and source records attributed to A Mo.

At least 19 recordsLinked to original sources
PubMed2002

Estrogen and "exercise" have a synergistic effect in preventing bone loss in the lumbar vertebra and femoral neck of the ovariectomized rat.

This study was designed to study the individual or combined effects of estrogen and bipedal stance "exercise" on the lumbar vertebral body (LVB) and femoral neck (FN). At 6 months of age, six rats were sacrificed as baseline controls and all the others were either bilateral sham-ovariectomized or ovariectomized (OVX). Groups of OVX rats were housed in normal height cage (NC, 28 cm) or raised height cages (RC, 33 cm) and received biweekly s.c. injections of 10 microg/kg 17 beta estradiol (E2) or vehicle for 4 and 8 weeks. Histomorphometric measurements were performed on the undecalcified mid-transverse sections of the 4th LVB and FN. Ovariectomy alone induced cancellous bone loss by 21% and 39% in the LVB and FN, respectively; intracortical porosity area of the FN increased by 108% while total bone area did not change significantly because of the periosteal expansion following OVX. E2 alone partially prevented cancellous bone loss in the LVB and FN and prevented increased intracortical porosity area in the FN by reducing eroded surface and activation frequency. RC alone partially prevented the decrease of cancellous bone in the LVB and FN by reducing the bone-eroded surface but increased wall width. E2 plus RC completely preserved cancellous bone by having an additive effect on reducing eroded surface and activation frequency. RC helped to partially prevent decreased periosteal bone formation after estrogen administration. In conclusion, apart from inducing cancellous bone loss in the LVB and FN, OVX also increased intracortical remodeling in the FN. Estrogen prevented the overall activation of remodeling space induced by OVX. Apart from having similar effects as estrogen on remodeling space, RC induced positive bone balance within each remodeling unit. Combination treatment increased total bone mass beyond that of sham-control level by having an additive effect on lowering bone remodeling and increasing wall in both the LVB and FN.

Animals↗
PubMed2002

Bipedal stance exercise and prostaglandin E2 (PGE2) and its synergistic effect in increasing bone mass and in lowering the PGE2 dose required to prevent ovariectomized-induced cancellous bone loss in aged rats.

Previous reports have shown that bone loss was partially prevented by bipedal stance "exercise" following ovariectomy (ovx), and it was well documented that prostaglandin E2 (PGE(2)) had an anabolic effect on the rat skeleton. The aim of this study was to determine whether lower doses of PGE(2) could prevent ovx-induced cancellous bone loss with the combination of bipedal stance exercise. Seventy-eight 10-month-old female Sprague-Dawley rats were either ovariectomized or sham-operated on day 0 and then treated with PGE(2) (0, 0.3, or 1 mg/kg per day) and/or housed in normal height cages (NC, 28 cm) or raised cages (RC, 33 cm) for 8 weeks. Bone histomorphometry was performed on the double-fluorescent-labeled proximal tibial metaphysis. In sham rats, 1 mg/kg PGE(2) + RC had synergistic effects in increasing trabecular bone area, width, and number by stimulating mineral apposition rate and bone formation rate. As expected, ovx induced cancellous bone loss, accompanied by elevated activation frequency. Without RC, PGE(2) monotherapy prevented ovx-induced bone loss at the 1 mg/kg per day dose, whereas this prevention effect was observed at the 0.3 mg/kg per day dose when combined with RC. Similar to their effects in sham rats, PGE(2) and RC had synergistic effects in augmenting cancellous bone mass and architecture and maintaining the elevated bone formation but depressing bone resorption and activation frequency. We conclude that bipedal stance exercise lowers the PGE(2) dose required to prevent ovx-induced cancellous bone loss in the proximal tibial metaphysis in aged rats.

Animals↗
PubMed2001

[A two-years clinical observation of all-ceramic restorations using Vita In-Ceram glass-infiltrated ceramic].

OBJECTIVE: This paper observed the clinical effect of Vita In-Ceram glass-infiltrated ceramic restorations. METHOD: A total of 194 restorations (124 maxillary and 70 mandibular prostheses) made with Vita In-Ceram glass-infiltrated ceramic were examined in 45 patients. There were 165 anterior tooth crowns, 21 posterior tooth crowns, and 8 FPDs. Surface, color, anatomic form, and marginal integrity of restorations were assessed at 3 months, 6 months, 1 year and 2 years after cementation with the California Dental Association (CDA) quality assessment evaluation system. RESULTS: It showed that the marginal fitness, color stability and strength of crowns were considered to be satisfactory. Only 0.01% (two crowns) were not acceptable. Two FPDs were not acceptable at 6-month visit, however, the anterior FPDs were considered to be satisfactory. CONCLUSION: It is possible to constructexcellent all-ceramic prostheses with the Vita In-Ceram glass-infiltrated ceramic system.

Ceramics↗
PubMed2001

[A study on the bond interface between low-fusing dental porcelain and pure titanium].

OBJECTIVE: To evaluate the bond interface between low fusing dental porcelain and pure titanium by observing the topography and detecting the ionic diffusion in the interface area. METHODS: The low fusing-porcelain La-porcelain produced by the authors or Vita Titankeramik porcelain was fused to the surfaces of pure titanium. The topography of the interface between pure titanium and porcelain, and the structure of experimental materials were observed with SEM. The state of ionic diffusion in the interface area was investigated with EPMA. RESULTS: Excellent permeation and diffusion of La-porcelain were observed on the surfaces of pure titanium. The diffusion of ions of stannum and silicon was discovered in the interface area. The microstructure of La-porcelain to pure titanium bond interface was finer than that of Vita Titankeramik porcelain. CONCLUSION: Excellent bond can be produced in the interface between La-porcelain and pure titanium. The bonding mechanism may involve mechanical bond and chemical bond. The ionic diffusion of stannum plays an important role in the bonding of porcelain to pure titanium.

Dental Alloys↗
PubMed2001

[The influences of crystallized compositions in the porcelain on bonding strength of titanium to porcelain].

OBJECTIVE: Sufficient porcelain-titanium bond is a vital factor determining the clinical performance of titanium-porcelain restorations. The purpose of this study was to investigate the effects of self-preparation La-porcelain composition on the porcelain-titanium bonding strength and to compare with the Vita Titankeramik. METHODS: The present study examines 5 different recipes of porcelain by weight%: SiO2, 12%-17%; LaO2, 7%-10%; Al2O3, 9%-14%; B2O3, 23%-31%; CaO, 6%-8%; K2O, 2%-3%; SrO, 2%-4%; Na2O, 1%-3%; SnO2, 8%-10%; ZrO2, 3%-5%; TiO2, 6%-8%. Specimens were tested in push type shear with a universal testing machine. Scanning electron microscopy (SEM) and electron probe microanalyzer (EPMA) were employed to reveal the microstructures and diffusion of elements in the interfacial regions between the porcelain coating and titanium to the bond strength when fired at 800 degrees C. RESULTS: The ratios of crystallized compositions had significant influences on the porcelain-titanium bond strength (P < 0.05). La-porcelain had the highest shear bond strength (37.76 MPa). The shear bond strength of the Vita Titankeramik to titanium was 20.18 MPa. The results of SEM revealed integrity of porcelain-titanium joints in La-porcelain and a greater amount of porosity in the interface of Vita Titankeramik to titanium. EPMA analysis demonstrated the aggregation of Si and Sn in the interfacial regions and their diffusion into the titanium. CONCLUSION: Chemical compositions of porcelain and ratios of crystallized compositions play the important role in the titanium porcelain bond. La-porcelain had the highest shear bond strength and good porcelain-titanium joints. La-porcelain is a new-style low fusing porcelain/titanium system.

Crystallization↗
PubMed1991

Complex segregation analysis of autism.

A complex segregation analysis of autism in 185 Utah families was carried out using the mixed model. The 209 affected individuals in these families represent nearly complete ascertainment of the autistic cases born in Utah between 1965 and 1984. The sibling recurrence risk for autism was 4.5% (95% confidence limits 2.8%-6.2%). Likelihoods were maximized for major-gene models, a polygenic model, a sibling-effect model, and a mixed model consisting of major-gene and shared-sibling effects. The analysis provided no evidence for major-locus inheritance of autism. Subdivision of the sample according to the probands' IQ levels showed that sibling recurrence risk did not vary consistently with IQ level. A segregation analysis of families in which the proband had an IQ less than 50 also failed to provide evidence for a major locus. However, because of the etiologic heterogeneity of this disorder, genetic analysis of other meaningful subsets of families could prove informative.

Autistic Disorder↗
PubMed1990

The UCLA-University of Utah epidemiologic survey of autism: genealogical analysis of familial aggregation.

To assess familial aggregation of autism, 86 autistic subjects were linked to the Utah Genealogical Database. Kinship coefficients were estimated for all possible pairs of autistic subjects and then averaged. Fifty replicate sets of matched control subjects (86 members in each set) were drawn randomly from the database, and the average kinship coefficient was computed for all possible pairs of individuals in each set. The average kinship coefficient for the autistic subjects was approximately 1/1,000, while the average kinship coefficients for the 50 control groups ranged from 4/100,000 to 1.6./10,000. These results indicate a strong tendency for autism to cluster in families. When kinship was analyzed by specific degrees of relationship, it was shown that the familial aggregation of autism is confined exclusively to sib pairs and does not extend to more remote degrees of relationship. This finding indicates that a single-gene model is unlikely to account for most cases of autism.

Autistic Disorder↗
PubMed1990

The UCLA-University of Utah epidemiologic survey of autism: the etiologic role of rare diseases.

Twelve rare diseases known to cause CNS pathology were found in 26 (11%) of 233 autistic probands identified during a recent epidemiologic survey of Utah. These 26 probands had significantly lower mean IQs than the remaining patients (43 versus 60) but similar sex distribution and prevalence of abnormal EEGs and seizures. The rarity and diversity of these 12 diseases make it highly unlikely that they randomly occurred with autism. Their presence in this epidemiologic survey is the most compelling evidence to date to support the hypothesis that different diseases producing different types of CNS pathology can play an etiologic role in autism.

Adult↗
PubMed1990

The UCLA-University of Utah epidemiologic survey of autism: prenatal, perinatal, and postnatal factors.

In a recent epidemiologic survey conducted in Utah, 241 autistic patients (DSM-III criteria) were found. Medical records of 233 autistics were surveyed for the presence of 36 potentially pathologic prenatal, perinatal, and postnatal factors. These results were compared with those of an identical survey of 62 of their nonautistic siblings, with the results of four previously published surveys, and with normative data. No potentially pathologic factor or group of factors occurred significantly more frequently among the autistic patients. Also, previous observations of significant differences in the occurrence of certain factors in the histories single vs multiple siblings with autism were not confirmed, with the exception of increased viral-type illness during gestation in single-incidence cases. Thus, the etiology of the brain pathology that characteristically disrupts normal development and produces the syndrome of autism remains obscure. Other data from the epidemiologic survey, however, suggest that the role of genetic factors needs to be explored further.

Apgar Score↗
PubMed1989

The UCLA-University of Utah epidemiologic survey of autism: prevalence.

The authors conducted an epidemiologic survey in Utah using a four-level ascertainment system, blind current diagnostic assessments, and DSM-III criteria. Of 483 individuals ascertained, 241 were diagnosed as having autism. The best estimate for the prevalence rate was 4 per 10,000 population. Autism was not associated with parental education, occupation, racial origin, or religion. Sixty-six percent of the autistic subjects scored below 70 on standardized IQ tests, and females scored proportionately lower than males. Twenty (9.7%) of 207 families had more than one autistic sibling, which supports the authors' previous finding that there may be a familial subtype of autism.

Adolescent↗
PubMed1989

Psychometric assessment of first-degree relatives of 62 autistic probands in Utah.

The Wechsler Intelligence Scales, Wide Range Achievement Test, and the Shipley-Hartford Test were administered to 122 parents and 153 siblings of 62 autistic probands in Utah. Scores were distributed as expected within the published normative ranges for each scale. Parents' scores correlated with those of their nonautistic children, but neither parents' nor siblings' scores correlated with the IQ level of the autistic probands. These results do not confirm prior reports from England and the United States of a high rate of cognitive and learning problems in the siblings of autistic individuals, nor the aggregation of such problems in the siblings of probands with high or low levels of cognitive function.

Achievement↗
PubMed1989

The UCLA-University of Utah epidemiologic survey of autism: recurrence risk estimates and genetic counseling.

The authors recently reported, in this journal, an epidemiologic survey of autism in Utah. Twenty (9.7%) of the 207 families ascertained had more than one autistic child. Analyses of these data revealed that autism is 215 times more frequent among the siblings of autistic patients than in the general population. The overall recurrence risk estimate (the chance that each sibling born after an autistic child will develop autism) is 8.6%. If the first autistic child is a male the recurrence risk estimate is 7%, and if a female 14.5%. These new recurrence risk estimates should be made available to all individuals who have autistic children and are interested in family planning.

Autistic Disorder↗
PubMed1985

Concordance for the syndrome of autism in 40 pairs of afflicted twins.

The UCLA Registry for Genetic Studies in Autism was established in 1980 to test the hypothesis that genetic factors may be etiologically significant in subsets of patients. To date 61 pairs of twins have enrolled and 40 meet research diagnostic criteria for autism. The authors found a concordance for autism in these 40 pairs of 95.7% in the monozygotic twins (22 of 23) and 23.5% in the dizygotic twins (four of 17).

Adolescent↗
PubMed1985

Evidence for autosomal recessive inheritance in 46 families with multiple incidences of autism.

The authors ascertained 46 families with multiple incidences of autism (41 with two and five with three autistic probands). Classical segregation analyses revealed a maximum likelihood estimate of the segregation ratio of p = 0.19 +/- 0.07. This is not significantly less than 0.25, the expected value for autosomal recessive inheritance. However, it is significantly less than 0.50, the expected value for autosomal dominant inheritance. The polygenic threshold model was tested and rejected over a full range of values of heritability and ascertainment probability for these families. These results are most consistent with the hypothesis of autosomal recessive inheritance in this subset of 46 families with multiple incidences of autism.

Adolescent↗
PubMed1980

Relationship between plasma pH and pancreatic HCO3- secretion at different intravenous secretin infusion rates.

The relationship between pancreatic HCO3- secretion and plasma pH during acute systemic acid-base changes was investigated in 6 anesthetized, artificially ventilated pigs (20-25 kg) at 2 different, i.v. secretion infusion rates. At 0.45 C.U./kg b. wt. h-1 secretin infusion and plasma pH 7.40 +/- 0.01 pancreatic HCO3- secretion averaged 61+/- 12 mumol/min. Stepwise lowering of plasma pH through i.v. infusion of HCl and CO2 administration to inspired air proportionately reduced secretion rate; estimated zero HCO3- secretion occurring at plasma pH 7.01. Subsequent i.v. secretin infusion at 2.70 C.U./kg b. wt. h-1 increased HCO3- secretion to 249 +/- 42 mumol/min at plasma pH 7.33 + 0.04; stepwise lowering of plasma pH proportionately reduced HCO3- secretion to estimated zero at plasma pH 6.71. A reduction of plasma pH by 0.1 pH unit reduced HCO3- secretion during low and high rate of i.v. secretin infusion by 18 +/- 3 mumol/min and 35 +/- 8 mumol/min, respectively. Secretin infusion rate did not affect pancreatic chloride excretion. These findings support the view that secretin increases HCO3- secretion, and hence proton transport to the interstitial fluid, by augmenting the proton motive force developed by HCO3- secreting cells.

Animals↗
PubMed1980

Influence of click sound pressure direction on brain stem responses in children.

Brain stem auditory responses were evoked by stimulation with condensation (C) and rarefaction (R) clicks separately. The latencies of the first five waves of the response were compared in response to the two sound pressure directions. Responses to R clicks were significantly shorter than responses to C clicks for wave 4, in the absence of consistent response differences in the other waves.

Acoustic Stimulation↗