Comparison of cone beam CT scans with enhanced photostimulated phosphor plate images in the detection of root fracture of endodontically treated teeth.

OBJECTIVES: Two-dimensional intraoral radiography is the most common tool for diagnosing root fractures (RFs). Cone beam CT (CBCT) is widely used to depict RFs in endodontically treated teeth. Beam hardening and other artefacts caused by gutta percha may result in an incorrect diagnosis when using CBCT only. A comparison of two CBCT machines with photostimulated phosphor (PSP) plate images enhanced with the equalization tool was carried out to detect RFs in endodontically treated teeth. METHODS: 66 roots were collected, decoronated and treated endodontically using the same technique with gutta percha. 33 of these roots were randomly selected and fractured; the 2 root fragments were glued together with 1 layer of methyl methacrylate and placed randomly in 8 prepared beef rib fragments. Large fields of view (FOVs) were acquired with one CBCT unit and small FOVs with the second CBCT unit. Periapical radiographs (using intraoral PSP plates) were also acquired. A contrast enhancement tool was used when evaluating the PSP plate images. RESULTS: Small FOV images had significantly higher accuracy (area under the receiver operating characteristic curve) and sensitivity in detecting RFs than PSP plates and large FOV images. The specificity of the enhanced PSP images was higher than, although not significantly higher than, the small FOV images and was significantly higher than the large FOV images. CONCLUSIONS: CBCT small FOVs should be acquired for depicting RFs of endodontically treated teeth. Images obtained using PSP plates had the lowest rate of false-positive results and their use can save the patient a radiation dose.

Evaluation of a cone beam CT artefact reduction algorithm.

OBJECTIVES: An algorithm and software to reduce metal artefact has been developed recently and is available in the Picasso Master 3D® (VATECH, Hwaseong, Republic of Korea), which under visual assessment produces better quality images than were obtainable previously. The objective of this in vitro study was to investigate whether the metal artefact reduction (MAR) algorithm of the Picasso Master 3D machine reduced the incidence of metal artefacts and increased the contrast-to-noise ratio (CNR) while maintaining the same gray value when there was no metallic body present within the scanned volume. METHODS: 20 scans with a range of 50-90 kVp were acquired, of which 10 had a metallic bead inserted within a phantom. The images obtained were analysed using public domain software (ImageJ; NIH Image, Bethesda, MD). Area histograms were used to evaluate the mean gray level variation of the epoxy resin-based substitute (ERBS) block and a control area. The CNR was calculated. RESULTS: The MAR algorithm increased the CNR when the metallic bead was present; it enhanced the ERBS gray level independently of the presence of the metallic bead. The image quality also improved as peak tube potential was increased. CONCLUSION: Improved quality of images and regaining of the control gray values of a phantom were achieved when the MAR algorithm was used in the presence of a metallic bead.

Metal artefact reduction with cone beam CT: an in vitro study.

BACKGROUND: Metal in a patient's mouth has been shown to cause artefacts that can interfere with the diagnostic quality of cone beam CT. Recently, a manufacturer has made an algorithm and software available which reduces metal streak artefact (Picasso Master 3D® machine; Vatech, Hwaseong, Republic of Korea). OBJECTIVES: The purpose of this investigation was to determine whether or not the metal artefact reduction algorithm was effective and enhanced the contrast-to-noise ratio. METHODS: A phantom was constructed incorporating three metallic beads and three epoxy resin-based bone substitutes to simulate bone next to metal. The phantom was placed in the centre of the field of view and at the periphery. 10 data sets were acquired at 50-90 kVp. The images obtained were analysed using a public domain software ImageJ (NIH Image, Bethesda, MD). Profile lines were used to evaluate grey level changes and area histograms were used to evaluate contrast. The contrast-to-noise ratio was calculated. RESULTS: The metal artefact reduction option reduced grey value variation and increased the contrast-to-noise ratio. The grey value varied least when the phantom was in the middle of the volume and the metal artefact reduction was activated. The image quality improved as the peak kilovoltage increased. CONCLUSION: Better images of a phantom were obtained when the metal artefact reduction algorithm was used.

Glycemic control and implant stabilization in type 2 diabetes mellitus.

Diabetes mellitus is considered a relative contra-indication for implant therapy. However, the effect of glycemic level on implant integration in persons with diabetes remains poorly understood. The hypothesis of this research was that poor glycemic control is directly related to short-term-impairment implant stabilization. This prospective clinical study evaluated 10 non-diabetic individuals (12 implants) and 20 persons with type 2 diabetes (30 implants). Glycated hemoglobin (HbA1c) levels ranged from 4.7-12.6%. Implant stability was assessed by resonance frequency analysis over 4 months following placement. Minimum stability levels were observed 2-6 weeks following placement for all 42 implants. Persons with HbA1c > or = 8.1% had a greater maximum decrease in stability from baseline and required a longer time for healing, as indicated by return of stability level to baseline. This study demonstrates alterations in implant stability consistent with impaired implant integration for persons with type 2 diabetes mellitus in direct relation to hyperglycemic conditions.

Rodent model for investigating the effects of estrogen on bone and muscle relationship during growth.

It has been reported that in humans from about 11-12 years of age, bone mass begins to increase faster in girls than in boys with the same muscle mass, and by 14-15 years of age, bone mass per unit mass of muscle was found to be significantly higher in girls than in boys. Because around 15 years is the beginning of reproductive age in women, it was suggested that estrogen was involved in the higher bone mass in women during puberty. The present study was undertaken to determine if bone mass per unit muscle mass is higher in female than in male Sprague Dawley (SD) rats during growth, as has been reported in humans during growth and consequently, whether these SD rats are suitable for studying the musculoskeletal effects of estrogen, as may occur in humans during growth. L-4 vertebra of female and male SD rats aged 1-6 months were studied using peripheral quantitative computed tomography (pQCT). Muscle cross-sectional area was measured as a surrogate for muscle mass and bone mineral content (BMC) was measured as a surrogate for bone mass. From 1 to 6 months of age, total BMC, cortical BMC, and cancellous BMC increased faster in females than in males with similar muscle area, and at 3 and 6 months of age, the above vertebral indices of bone mass were significantly higher in female than in male rats. Since one of the main differences between female and male rats is the level of serum estrogen, the higher bone mass per unit muscle area seen at the L-4 vertebra in these female SD rats is similar to what has been reported in humans during puberty when serum estrogen level is high in females. The findings from this study indicate that female and male SD rats aged 1-6 months can be used as appropriate model for studying the effects of serum estrogen on the skeletal response of voluntary muscle forces, as has been reported in humans during growth.

Atherosclerosis in youth.

BACKGROUND: Coronary heart disease (CHD) and the related diseases due to atherosclerosis continue to be major public health problems in the industrialized countries and are likely to become serious problems in the developing countries. Treatment of end stage disease has improved, and risk factor modification has succeeded in reducing risk among adults. However, the age at which to begin risk factor control for long-range primary prevention is controversial. METHODS: A multicenter cooperative study, Pathobiological Determinants of Atheroscle-rosis in Youth (PDAY), was organized in 1985 to examine the relationship of the risk factors for adult CHD to preclinical atherosclerotic lesions in youth. Fourteen participating centers collected arteries, blood, other tissue, and data from 3,000 persons 15-34 years of age who died from external causes and were autopsied in forensic laboratories. Central laboratories evaluated atherosclerosis in the aorta and coronary arteries, measured lipoproteins and thio-cyanate (for smoking) in serum, glycohemo-globin in red blood cells (for blood glucose), thickness of small renal arteries (for hypertension), and body mass index (for obesity). The data were analyzed to determine the progression of atherosclerosis with age in both sexes and the association of the risk factors with atherosclerotic lesions. RESULTS: Raised lesions of the coronary arteries, the advanced lesions of atherosclerosis that lead directly to CHD, are associated positively with non-HDL cholesterol concentration, hypertension, obesity (in men), and blood glucose concentration; and inversely, with HDL cholesterol concentration. Smoking affects predominantly the abdominal aorta. CONCLUSIONS: These results suggest that long-range prevention of CHD should begin in adolescence or at least in young adulthood with control of the major established risk factors for adult CHD.

Spontaneous hepatocellular carcinoma is reduced in transgenic mice overexpressing human O6- methylguanine-DNA methyltransferase.

O(6)-methylguanine (O(6)mG) is a potent mutagenic and procarcinogenic DNA lesion. Organisms have evolved with a DNA repair mechanism that largely ameliorates the deleterious effects of O(6)mG through a direct reversal mechanism by a protein termed O(6)-methylguanine-DNA methyltransferase (MGMT). However, the contribution of O(6)mG to carcinogenesis, in the absence of known exposure to agents that produce it, has not been defined. Nontransgenic C3HeB male mice have a high frequency of spontaneous liver tumors. Transgenic CeHeB/FeJ mice expressing human MGMT (hMGMT) were generated that had elevated hepatic MGMT activity. The spontaneous development of hepatocellular carcinoma was significantly reduced in those mice expressing hMGMT compared with nontransgenic C3HeB/FeJ male mice. No differences were detected in spontaneous mutant frequencies in lacI transgenes in mice carrying hMGMT compared with that without hMGMT but the proportion of GC to AT transition mutations was lower in the transgenic mice carrying hMGMT as well as lacI. Tumors that arose in C3HeB/FeJ transgenic mice were largely deficient in hMGMT protein as determined by immunohistochemistry with a monoclonal antibody directed against hMGMT. Together these data indicate that spontaneous O(6)mG lesions induced hepatocellular carcinogenesis in C3HeB/FeJ male mice. These transgenic mice represent a rare example of reduced spontaneous carcinogenesis.

Male rodent model of age-related bone loss in men.

Osteoporosis is a common occurrence in aging men. There is currently no appropriate animal model for studying age-related bone loss in men. To determine whether male Sprague-Dawley (SD) rats experience bone loss with aging and whether this rodent model is appropriate for studying age-related bone loss in men, SD rats aged 1-27 months were examined at the L-4 vertebra, the left femoral neck, and the left proximal tibia using peripheral quantitative computed tomography (pQCT) densitometry. In the L-4 vertebra of the male SD rats, cortical bone mineral content (BMC), cortical bone mineral density (BMD), and cortical bone thickness (Ct.Th) increased to a maximum at about 4 months of age and then plateaued. Vertebral cortical BMC began to decrease after about 13 months and vertebral Ct.Th began to decrease after about 9 months. By 27 months of age, vertebral cortical BMC decreased by 26.1% (p < 0.0001) and vertebral Ct.Th decreased by 31% (p < 0.0001). Vertebral cancellous BMC and vertebral cancellous BMD increased to a maximum at about 3 months of age and then declined progressively with aging after a short plateau. From 3 to 27 months of age, vertebral cancellous BMC and vertebral cancellous BMD had decreased linearly by 35.4% (p < 0.0001) and 49.4% (p < 0.0001), respectively. Both vertebral periosteal and vertebral endocortical perimeters of the L-4 vertebra of the rats increased with aging. From 9 to 27 months of age, the percent increase of vertebral endocortical perimeter (19.8%, p < 0.0001) was higher than that of vertebral periosteal perimeter (7.4%, p < 0.0001). This process was associated with a decrease with aging in vertebral Ct.Th. In addition, cancellous bone in the femoral neck and the proximal tibia began to be lost at 9 months of age and, by 27 months of age, cancellous BMC and cancellous BMD decreased by 59.7% (p < 0.0001) and 58.4% (p < 0.0001), respectively, in the femoral neck and by 72.2% (p < 0.0001) and 71.4% (p < 0.0001), respectively, in the proximal tibia. To gain further insight into the effects of aging on cancellous bone in the L-4 vertebra, histomorphometry was done on the L-4 vertebral body of animals aged 3, 6, 9, 18, and 24 months after pQCT densitometry. From 3 months of age and thereafter, cancellous bone volume (BV/TV) decreased progressively and, by 24 months, there was a decrease of 35.7% (p < 0.0001). In the L-4 vertebra, single- and double-labeled surfaces, mineral apposition rate (MAR), and bone formation rate (BFR/BS) decreased with aging. In conclusion, age-related bone loss in male SD rats started mostly from 9 months of age when bone growth had been completed. Aging male SD rats experience bone loss comparable to that seen in men. Thus, male SD rats represent an appropriate animal model of age-related bone loss in men. We recommend using male SD rats that are 9 months old as the starting age for age-related bone loss. We also suggest using the L-4 vertebra and femoral neck as the clinically relevant bone sites for determining the cause of the loss of bone, and how and whether therapeutic agents could modulate age-related bone loss in men.

Effects of nonlipid risk factors on atherosclerosis in youth with a favorable lipoprotein profile.

BACKGROUND: The strong association between coronary heart disease and dyslipoproteinemia has often overshadowed the effects of the nonlipid risk factors-smoking, hypertension, obesity, and diabetes and impaired glucose tolerance-and even led to questioning the importance of these risk factors in the presence of a favorable lipoprotein profile. METHODS AND RESULTS: A cooperative multicenter study, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY), examined the relation of the nonlipid risk factors to atherosclerosis in 629 men and 227 women 15 to 34 years of age who died of external causes and who had a favorable lipoprotein profile (non-HDL cholesterol <4.14 mmol/L [<160 mg/dL] and HDL cholesterol >/=0.91 mmol/L [>/=35 mg/dL]). In the abdominal aorta, smokers had more extensive fatty streaks and raised lesions than nonsmokers, and hypertensive blacks had more raised lesions than normotensive blacks. In the right coronary artery, hypertensive blacks had more raised lesions than normotensive blacks, obese men (body mass index >/=30 kg/m(2)) had more extensive fatty streaks and raised lesions than nonobese men, and individuals with impaired glucose intolerance had more extensive fatty streaks. Obese men had more severe lesions (American Heart Association grade 2 through 5) of the left anterior descending coronary artery. CONCLUSIONS: These substantial effects of the nonlipid risk factors on the extent and severity of coronary and aortic atherosclerosis, even in the presence of a favorable lipoprotein profile, support the need to control all cardiovascular risk factors.

Mixed spermatogenic germ cell nuclear extracts exhibit high base excision repair activity.

Spermatogenic cells exhibit a lower spontaneous mutation frequency than somatic tissues in a lacI transgene and many base excision repair (BER) genes display the highest observed level of expression in the testis. In this study, uracil-DNA glycosylase-initiated BER activity was measured in nuclear extracts prepared from tissues obtained from each of three mouse strains. Extracts from mixed spermatogenic germ cells displayed the greatest activity followed by liver then brain for all three strains, and the activity for a given tissue was consistent among the three strains. Levels of various BER proteins were examined by western blot analyses and found to be consistent with activity levels. Nuclear extracts prepared from purified Sertoli cells, a somatic component of the seminiferous epithelium, exhibited significantly lower activity than mixed spermatogenic cell-type nuclear extracts, thereby suggesting that the high BER activity observed in mixed germ cell nuclear extracts was not a characteristic of all testicular cell types. Nuclear extracts from thymocytes and small intestines were assayed to assess activity in a mitotically active cell type and tissue. Overall, the order of tissues/cells exhibiting the greatest to lowest activity was mixed germ cells > Sertoli cells > thymocytes > small intestine > liver > brain.

Suicide by firearms: a 15-year experience.

A retrospective review of 1704 cases of suicide involving firearms investigated by the Bexar County Medical Examiner's office between 1984 and 1998 was performed. The age distribution was similar in male and female victims, and the type of weapon was not associated with age. Approximately 78% of the victims used a handgun (87% of female and 76% of male victims). In 4.0% of head wound cases, the site of the entrance wound was the back of the head. Thus, this report refutes the common belief that all gunshot wounds to the back of the head represent homicides. In 1.9% of the cases, the wounds were inflicted at intermediate range. With handguns, the right temple was the most common site, but with rifles and shotguns, the most common site was the mouth.

Health span and life span in transgenic mice with modulated DNA repair.

One way to better understand the contribution of DNA repair, DNA damage, and mutagenesis in aging would be to enhance DNA repair activity, lower DNA damage, and lower mutagenesis. Because the repair protein O6-methylguanine-DNA methyltransferase (MGMT) acts alone and stoichiometrically, the human MGMT (hMGMT) cDNA was selected to test the feasibility of enhancing DNA repair activity in transgenic mice. MGMT activity is largely responsible for ameliorating the deleterious effects of O6-methylguanine (O6mG) lesions in DNA in a direct reversal mechanism. A transgene was constructed consisting of a portion of the human transferrin (TF) promoter and hMGMT cDNA such that hMGMT is expressed in transgenic mouse brain and liver. Expression of hMGMT was associated with a significant reduction in the occurrence of an age-related hepatocellular carcinoma in male mice at 15 months of age. Longitudinal and cross-sectional studies were initiated to determine whether the reduced incidence of hepatocellular carcinoma would impact median or maximum life span. The cross-sectional study performed on 15-month-old male animals confirmed the reduced occurrence of spontaneous hepatocellular carcinoma. At 30 months of age, however, the occurrence of hepatocellular carcinoma in at least one transgenic line was similar to that for nontransgenic animals. The longitudinal study is ongoing; however, at present no significant differences in life span have been detected. Tissues expressing the MGMT transgene also displayed greater resistance to alkylation-induced tumor formation. These results suggest that transgenes can be used to direct enhanced DNA repair gene expression and that enhanced expression can protect animals from certain spontaneous and induced tumors.

Origin of atherosclerosis in childhood and adolescence.

Atherosclerosis begins in childhood as deposits of cholesterol and its esters, referred to as fatty streaks, in the intima of large muscular arteries. In some persons and at certain arterial sites, more lipid accumulates and is covered by a fibromuscular cap to form a fibrous plaque. Further changes in fibrous plaques render them vulnerable to rupture, an event that precipitates occlusive thrombosis and clinically manifest disease (sudden cardiac death, myocardial infarction, stroke, or peripheral arterial disease). In adults, elevated non-HDL-cholesterol concentrations, low HDL-cholesterol concentrations, hypertension, smoking, diabetes, and obesity are associated with advanced atherosclerotic lesions and increased risk of clinically manifest atherosclerotic disease. Control of these risk factors is the major strategy for preventing atherosclerotic disease. To determine whether these risk factors also are associated with early atherosclerosis in young persons, we examined arteries and tissue from approximately 3000 autopsied persons aged 15-34 y who died of accidental injury, homicide, or suicide. The extent of both fatty streaks and raised lesions (fibrous plaques and other advanced lesions) in the right coronary artery and in the abdominal aorta was associated positively with non-HDL-cholesterol concentration, hypertension, impaired glucose tolerance, and obesity and associated negatively with HDL-cholesterol concentration. Atherosclerosis of the abdominal aorta also was associated positively with smoking. These observations indicate that long-range prevention of atherosclerosis and its sequelae by control of the risk factors for adult coronary artery disease should begin in adolescence and young adulthood.

Associations of coronary heart disease risk factors with the intermediate lesion of atherosclerosis in youth. The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.

The raised fatty streak (fatty plaque) is the gross term for the lesion intermediate between the juvenile (flat) fatty streak and the raised lesion of atherosclerosis. We measured the percentage of intimal surface involved with flat fatty streaks, raised fatty streaks, and raised lesions in the aortas and right coronary arteries of 2876 autopsied persons aged 15 through 34 years who died of external causes. Raised fatty streaks were present in the abdominal aortas of approximately 20% of 15- to 19-year-old subjects, and this percentage increased to approximately 40% for 30- to 34-year-old subjects. Raised fatty streaks were present in the right coronary arteries of approximately 10% of 15- to 19-year-old subjects, and this percentage increased to approximately 30% for 30- to 34-year-old subjects. The percent intimal surface involved with raised fatty streaks increased with age in both arteries and was associated with high non-high density lipoprotein (HDL) and low HDL cholesterol concentrations in the abdominal aorta and right coronary artery, with hypertension in the abdominal aorta, with obesity in the right coronary artery of men, and with impaired glucose tolerance in the right coronary artery. Associations of risk factors with raised fatty streaks became evident in subjects in their late teens, whereas associations of risk factors with raised lesions became evident in subjects aged >25 years. These results are consistent with the putative transitional role of raised fatty streaks and show that coronary heart disease risk factors accelerate atherogenesis in the second decade of life. Thus, long-range prevention of atherosclerosis should begin in childhood or adolescence.

Association of Coronary Heart Disease Risk Factors with microscopic qualities of coronary atherosclerosis in youth.

BACKGROUND: This study examined whether atherosclerosis in young people is associated with the risk factors for clinical coronary heart disease (CHD). Methods and Results-Histological sections of left anterior descending coronary arteries (LADs) from 760 autopsied 15- to 34-year-old victims of accidents, homicides, and suicides were graded according to the American Heart Association (AHA) system and computerized morphometry. Risk factors (dyslipoproteinemia, smoking, hypertension, obesity, impaired glucose tolerance) were assessed by postmortem measurements. Approximately 2% of 15- to 19-year-old men and 20% of 30- to 34-year-old men had AHA grade 4 or 5 (advanced) lesions. No 15- to 19-year-old women had grade 4 or 5 lesions; 8% of 30- to 34-year-old women had such lesions. Approximately 19% of 30- to 34-year-old men and 8% of 30- to 34-year-old women had atherosclerotic stenosis > or =40% in the LAD. AHA grade 2 or 3 lesions (fatty streaks), grade 4 or 5 lesions, and stenosis > or =40% were associated with non-HDL cholesterol > or =4.14 mmol/L (160 mg/dL). AHA grade 2 or 3 lesions were associated with HDL cholesterol <0.91 mmol/L (35 mg/dL) and smoking. AHA grade 4 or 5 lesions were associated with obesity (body mass index > or =30 kg/m(2)) and hypertension (mean arterial pressure > or =110 mm Hg). CONCLUSIONS: -Young Americans have a high prevalence of advanced atherosclerotic coronary artery plaques with qualities indicating vulnerability to rupture. Early atherosclerosis is influenced by the risk factors for clinical CHD. Long-range prevention of CHD must begin in adolescence or young adulthood.

Effects of coronary heart disease risk factors on atherosclerosis of selected regions of the aorta and right coronary artery. PDAY Research Group. Pathobiological Determinants of Atherosclerosis in Youth.

We examined topographic distributions of atherosclerosis and their relation to risk factors for adult coronary heart disease in right coronary arteries and abdominal aortas of more than 2000 autopsied persons 15 through 34 years of age. We digitized images of Sudan IV-stained fatty streaks and of manually outlined raised lesions and computed the percent surface area involved by each lesion in each of 6 regions of each artery. In abdominal aortas of 15- to 24-year-old persons, fatty streaks involve an elongated oval area on the dorsolateral intimal surface and another oval area in the middle third of the ventral surface. Raised lesions in 25- to 34-year-old persons involve an oval area in the distal third of the dorsolateral intimal surface. In other areas of the abdominal aortas of older persons, fatty streaks occur but raised lesions are rare. In the right coronary arteries of 15- to 24-year-old persons, fatty streaks are most frequent on the myocardial aspect of the first 2 cm. Raised lesions follow a similar pattern in 25- to 34-year-old persons. High non-HDL cholesterol and low HDL cholesterol concentrations are associated with more extensive fatty streaks and raised lesions in all regions of both arteries. Smoking is associated with more extensive fatty streaks and raised lesions of the abdominal aorta, particularly in the dorsolateral region of the distal third of the abdominal aorta. Hypertension is not associated with fatty streaks in whites or blacks but is associated with more extensive raised lesions in blacks. Risk factor effects on arterial regions that are vulnerable to lesions are approximately 25% greater than risk factor effects assessed over entire arterial segments. These risk factor effects on vulnerable sites emphasize the need for risk factor control during adolescence and young adulthood to prevent or delay the progression of atherosclerosis.

Spontaneous repositioning of pathologically migrated teeth.

BACKGROUND: There is limited clinical evidence that pathologically migrated teeth may reposition themselves after conventional periodontal treatment. The current research was carried out to determine the frequency of spontaneous repositioning of pathologically migrated teeth after routine periodontal therapy, and to study the relation between the severity of migration and the degree of repositioning following treatment. METHODS: Sixteen patients with moderate to severe periodontal disease and presenting 33 diastema sites secondary to pathologic migration participated in this study. After conventional periodontal treatment had been performed, reactive repositioning was assessed by measuring the space between pathologically migrated teeth and adjacent teeth on study models obtained at baseline, re-evaluation at 6 weeks after scaling and root planing, and 4 months after surgery. RESULTS: After scaling and root planing only, 48.5% of all sites exhibited some degree of repositioning with 36.4% of all sites closing completely. After surgery (6 months after baseline observations), 69.7% of all sites exhibited some degree of repositioning with 51.5% of all sites closing completely. When only small to moderate diastemata were considered (<1 mm), 77.8% of sites closed completely. CONCLUSIONS: The findings of this study support the hypothesis that spontaneous repositioning after conventional periodontal treatment is likely, particularly when only light to moderate degrees of pathologic migration are considered. We hypothesize that this spontaneous movement is due to wound contraction during healing.

Prevalence and extent of atherosclerosis in adolescents and young adults: implications for prevention from the Pathobiological Determinants of Atherosclerosis in Youth Study.

CONTEXT: Atherosclerosis, the underlying cause of coronary heart disease, has been shown to be present even in young adults. OBJECTIVE: To document the extent and severity of atherosclerosis in adolescents and young adults in the United States. DESIGN AND SETTING: The Pathobiological Determinants of Atherosclerosis in Youth Study, a multi-institutional autopsy study conducted in US medical centers. Subjects A total of 2876 study subjects, between 15 and 34 years old, black and white, men and women, who died of external causes and underwent autopsy between June 1, 1987, and August 31, 1994. MAIN OUTCOME MEASURES: Extent, prevalence, and topography of atherosclerotic lesions. RESULTS: Intimal lesions appeared in all the aortas and more than half of the right coronary arteries of the youngest age group (15-19 years) and increased in prevalence and extent with age through the oldest age group (30-34 years). Fatty streaks were more extensive in black subjects than in white subjects, but raised lesions did not differ between blacks and whites. Raised lesions in the aortas of women and men were similar, but raised lesions in the right coronary arteries of women were less than those of men. The prevalence of total lesions was lower in the right coronary artery than in the aorta, but the proportion of raised lesions among total lesions was higher in the right coronary artery than in the aorta. CONCLUSIONS: Atherosclerosis begins in youth. Fatty streaks and clinically significant raised lesions increase rapidly in prevalence and extent during the 15- to 34-year age span. Primary prevention of atherosclerosis, as contrasted with primary prevention of clinically manifest atherosclerotic disease, must begin in childhood or adolescence.

Lipid and apolipoprotein predictors of atherosclerosis in youth: apolipoprotein concentrations do not materially improve prediction of arterial lesions in PDAY subjects. The PDAY Research Group.

We compared serum lipid and apolipoprotein predictors of atherosclerosis in cases from the multicenter study, Pathobiological Determinants of Atherosclerosis in Youth (PDAY). The lipid measures included HDL cholesterol (HDL-C) and non-HDL-C, and the apolipoprotein measures included concentrations of apoA1, apoB, and Lp(a), and sizes of the apo(a) proteins. We tested whether the apolipoprotein measures predicted atherosclerotic lesions as well as the more traditional lipid measures. We estimated extent of lesions as fatty streaks or raised lesions (fibrous plaques, complicated or calcified lesions) in 3 sites: thoracic aorta, abdominal aorta, and right coronary artery. Neither apoA1 nor apoB measures were as strongly or consistently correlated with extent of lesions as the corresponding lipid measure (HDL-C and non-HDL-C, respectively). Beyond the basic model that included sex, age, race, smoking status, hypertension, and the lipid measures, apoA1 and apoB added only an average 1.3% increased explanatory ability to the model, whereas HDL-C plus non-HDL-C added an average 2.5%. The results suggest that the traditional lipid measures are more useful than apolipoprotein measures for detecting young persons at high risk of precocious atherosclerosis. Because of large racial differences, the two Lp(a)-related measures, Lp(a) concentrations and apo(a) size, were evaluated in blacks and whites separately. Under these circumstances, neither of the Lp(a)-related measures was strongly or consistently correlated with extent of lesions.

Determinants of atherosclerosis in the young. Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.

A multicenter cooperative study, Pathobiological Determinants of Atherosclerosis in Youth, examined the relation of the risk factors for adult coronary artery disease to atherosclerosis in nearly 3,000 persons, aged 15-34 years, who died from accidents, homicides, and suicides and were autopsied in forensic laboratories. Very-low-density lipoprotein (VLDL) plus low-density lipoprotein (LDL) cholesterol levels were positively, and high-density lipoprotein (HDL) cholesterol levels were negatively, associated with both fatty streaks and raised lesions in the aorta and right coronary artery, particularly after age 25. Elevated glycohemoglobin levels were associated with raised lesions throughout the 15-34-year age span. Body mass index was associated with both fatty streaks and raised lesions of the right coronary artery in men but not in women. Smoking was associated with a 3-fold increase in raised lesions of the abdominal aorta in the 25-34-year age group. Women lagged after men in the extent of raised lesions in the right coronary artery by about 5 years, but the effects of risk factors in women, except for adiposity, were similar to those in men. The risk factors for adult coronary artery disease accelerate atherogenesis in the teenage years and their effects are amplified in young adulthood, 20-30 years before coronary artery disease becomes clinically manifest. Long-range prevention of adult coronary artery disease will require control of the risk factors early in life.