Using gated technetium-99m-sestamibi SPECT to characterize fixed myocardial defects as infarct or artifact

Perfusion-scan fixed defects may result from soft tissue attenuation, decreasing test specificity for coronary disease and myocardial infarction (MI). Gated 99mTc-sestamibi SPECT may help differentiate MI from artifact since fixed defects with decreased function (wall motion and thickening) probably represent MI, whereas attenuation artifacts either have normal function or at least do not demonstrate markedly reduced function. METHODS: Ungated resting and gated stress 99mTc-sestamibi SPECT was performed in 551 consecutive patients referred for evaluation of coronary disease. From resting and summed gated stress images, 180 patients (33%) were identified with isolated fixed defects. Function of the defects was assessed subjectively from gated stress images and results were correlated with clinical (history and/or ECG Q-waves) evidence of MI. RESULTS: Of 102 patients with fixed defects and clinical MI, 98 (96%) had abnormal defect function. Of 78 patients with no clinical MI, 18 (23%) had decreased function of the defect, possibly indicating silent MI. In 60 of the 78 patients (77%) with no clinical MI, defect function was normal. Because most (91%) of fixed defects with normal systolic function occurred in women with anterior fixed defects (48%) or men with inferior fixed defects (43%), these were most likely attenuation artifacts. By reclassifying patients with fixed defects and normal function as normal, patients with unexplained fixed defects (no clinical MI) decreased from 14% to 3%. CONCLUSION: Gating provides a valuable adjunct to 99mTc-sestamibi SPECT in characterizing fixed defects and potentially improving test specificity.     

Congenital abnormalities associated with limb deficiency defects: a population study based on cases from the Hungarian Congenital Malformation Registry (1975-1984)

Limb deficiency defects (LD) occurring among 1,575,904 births in Hungary during 1975-1984 were reviewed. The overall birth prevalence of LD was 1 in 1,816. This paper discusses the nature and distribution of the limb and other defects in the 275 (32%) children who had structural malformations in other systems. Two main forms of classification were used: morphologic and causal. Additional malformations were most commonly seen in infants with amelia, rudimentary limb (RL), radial/tibial (RT), intercalary or central axis (CA) LD and rarely in those with terminal transverse (TT) or ulnar/fibular (UF) defects. Upper limbs (81%) were involved significantly more often than lower limbs (42%) and there were more right-sided defects (83% vs. 71%) due to an excess of right arm involvement especially with radial ray and split hand anomalies. Single limb involvement was relatively common with amelia (88%), UF (82%), RT (50%), and TT (50%) defects. With other LD, multimelic involvement was more characteristic. This was usually symmetric with intercalary and RL defects but asymmetric with CA anomalies and digital deficiencies (DD). From a causal perspective, 17% of cases had genetic disorders, 52% had recognized associations, anomalies, sequences, environmental causes or patterns of unknown origin, and 31% had unknown patterns of malformations. The commonest entities were amnion disruption sequence (16% of cases) and VACTERL association (8%). Both of these disorders showed unusual temporal distribution. As anticipated, patterns of malformations differed with the type of LD. Amelia and digital amputations were often seen with body wall defects, atypical anencephaly or encephalocele, and cleft lip reflecting amnion disruption. Rudimentary limb was seen with anencephaly, omphalocele, renal agenesis, aberrant genitalia, and imperforate anus, reflecting defects of blastogenesis including the cloacal exstrophy and caudal regression sequences and Schisis association. Radial/tibial defects were associated with different patterns depending on whether the limb defects were unilateral or bilateral. Unilateral defects occurred with anomalies suggesting VACTERL association or the facio-auriculo-vertebral anomaly, while bilateral defects occurred more often in genetic or potentially genetic disorders including VACTERL with hydrocephalus. Central axis defects showed three main patterns of association: one reflecting the ectrodactyly-ectodermal dysplasia-clefting syndrome; one with tongue anomalies representing a variant of oro-mandibular-limb (Hanhart) anomaly, and the last with hydronephrosis indicating a group of "acro-renal" syndromes. Strong associations with other anomalies were not seen in the groups with TT, UF, or intercalary defects.     

Maternal cell-free viremia in the natural history of perinatal HIV-1 transmission: a meta-analysis

In different animal investigations Pyrost demonstrated osteoconductive and osteostimulative effects. In ectopic tissues and especially in conditions of low osteogenetic potency, the combination of Pyrost and autogenic bone marrow effects bone formation. In a clinical prospective study, Pyrost was implanted in 1117 cases in the following indications: Donor site defects after bone transplantation, bone defects after tumor resection, revision of THA, acetabuloplasty, fracture treatment, pseudarthrosis and lengthening osteotomy, spondylodesis. In 87.3% the regeneration of the bone defects was complete, in 8% a partial regeneration was found. Excessive bone formation took place in 2.7%, insufficient regeneration in 2.0% in cases of instability or infection. According to the clinical results Pyrost is a suitable bone substitute in small bone defects and it is a valuable completion to the autogenic bone graft in large defects. In disadvantageous bone bed Pyrost has to be augmented with bone marrow and in large segmental defects the combination with autogenic bone grafts is recommendable. Presupposition for the application of bone substitutes like Pyrost in large defects is a sufficient primary stability of the bone bed. The application in infected tissue is not favorable.     

Prevalence of morphologic defects in spermatozoa from beef bulls

OBJECTIVE: To determine the overall prevalence of morphologic defects in spermatozoa from beef bulls and to determine whether prevalence varies with the age of the bull. DESIGN: Cross-sectional observational study. ANIMALS: 2,497 beef bulls that were evaluated for breeding soundness in 1994 by 29 practicing veterinarians in a 5-state geographic region. PROCEDURE: Slides of spermatozoa from each bull were made and submitted by practicing veterinarians for morphologic evaluation. One hundred spermatozoa per slide were examined, and each was classified as having 1 of 9 morphologic defects or as normal. RESULTS: 63% of bulls evaluated were 10 to 12 months old, and 20% were 13 to 18 months old. A mean of 70.6% of spermatozoa was classified as normal. Most common defects were proximal droplets (8.4%), distal midpiece reflexes (6.7%), separated heads (5.5%), and distal droplets (3.8%). Other defects were seen < 2% of the time. Bulls 10 to 12 months of age had a higher prevalence of proximal and distal droplet defects than older bulls. CLINICAL IMPLICATIONS: Practitioners conducting breeding soundness evaluations in beef bulls must be aware of common spermatozoal defects. Bulls that are evaluated at a young age will have more defects than older bulls and should be reevaluated, particularly for those defects for which prevalence decreases with age.     

Prospective evaluation of viable myocardium by quantitative dipyridamole-thallium-201 scintigraphy and radionuclide ventriculography

Improvement of myocardial function is a major goal of coronary revascularization. Considerable interest remains in the preoperative identification of viable myocardium. We examined 26 consecutive patients with left ventricular dysfunction undergoing coronary artery bypass grafting. Serial dipyridamole-thallium imaging and radionuclide ventriculography was performed preoperatively and postoperatively. The relationship between preoperative and postoperative thallium perfusion and segmental wall motion was analyzed. The mean preoperative ejection fraction was 32 +/- 9 (21 to 51%) and increased to 41 +/- 12 (17 to 67%) postoperatively (p > 0.01). Seventy-seven percent of patients improved their global ejection fraction postoperatively by > 5%. Thallium perfusion improved postoperatively in 84% of reversible defects vs 63% of partially reversible defects and 35% of fixed defects. Segments with either reversible or partially reversible thallium defects showed an improved postoperative wall motion in 71% and 68%, respectively. Postoperative wall motion improved in 43% of fixed defects. Overall, 67% of hypokinetic segments showed improved postoperative wall motion while only 29% of akinetic or dyskinetic segments improved postoperatively. Preoperative thallium redistribution coupled with preserved wall motion was predictive of improvement in wall motion was predictive of improvement in wall motion postoperatively and indirectly indicates myocardial viability. However, 43% of fixed defects also showed improved postoperative wall motion. A significant improvement in global ejection fraction was found and could be predicted by a linear regression analysis utilizing clinical and thallium parameters.     

Impact of prenatal diagnosis and elective termination on the prevalence of selected birth defects in Hawaii

This study examined the effect of prenatal diagnosis and elective termination on the prevalence of neural tube defects, oral clefts, abdominal wall defects, and chromosomal anomalies in Hawaii by using actively ascertained surveillance data collected between 1987 and 1996 by the Hawaii Birth Defects Program. Because the Program has nearly universal access to prenatal diagnostic information and to follow-up data on elective terminations, Hawaii is an ideal setting in which to study their effects on prevalence rates of birth defects. Except for oral clefts, a large proportion of the defects studied were prenatally diagnosed: anencephaly (87%), spina bifida (62%), encephalocele (83%), cleft palate (0%), cleft lip with or without cleft palate (14%), omphalocele (60%), gastroschisis (76%), Down syndrome (43%), trisomy 18 (61 %), and trisomy 13 (40%). The effect of elective terminations on the birth prevalence rates for most of these birth defects was significant. Including electively terminated cases in the calculations of birth prevalence rates increased the rates by more than 50% for five of the 10 birth defects studied.     

Experimental study of the reaction pp-->pp pi 0 in the energy range 600-900 MeV

To compare regional thallium-201 SPECT redistribution patterns with rubidium-82 PET, we studied 81 patients with both imaging modalities. Sixty patients had significant coronary artery disease. All patients underwent PET imaging after dipyridamole infusion, while SPECT imaging was performed after exercise stress (38 patients) and dipyridamole (43 patients). Sixty-eight percent of patients with prior infarct had fixed defects on SPECT, compared to 39% with PET. Sixty-one percent of patients with prior infarct had PET perfusion defects which exhibited 'reflow' or normal rubidium-82 tracer uptake (p < 0.05 vs. SPECT). Similar results were seen in patients without prior infarct (26% fixed defects on SPECT vs. 12% for PET, p < 0.05). Regional analysis showed that 57% of fixed SPECT defects corresponded to PET defects with reflow or normal rubidium-82 uptake, while 78% of 'fixed' PET defects corresponded to fixed SPECT defects. PET reflow and normal rubidium-82 uptake in sites of fixed thallium-201 SPECT perfusion defects suggest that imaging modalities employing separate tracer injections at rest and after stress, such as rubidium-82 PET, may be more specific in the assessment of myocardial viability, especially in patients with prior myocardial infarction.     

Trends and patterns of mortality associated with birth defects and genetic diseases in the United States, 1979-1992: an analysis of multiple-cause mortality data

Contemporary information on the trends and patterns of mortality associated with birth defects and genetic diseases is lacking in the United States. To study these trends and patterns, we used the Multiple-Cause Mortality Files of the National Center for Health Statistics. From 1979 through 1992, 320,208 deaths in the United States were associated with birth defects and genetic diseases. The age-adjusted mortality rates for people with birth defects declined from about 8.2/100,000 in 1979 to about 6.7/100,000 in 1992, and the mortality rates for people with genetic diseases increased from 2.2/100,000 in 1979 to 2.5/100,000 in 1992. The mortality rate was higher among men than among women and higher among blacks than among whites or other races for both birth defect- and genetic disease-associated deaths. The rate among infants with birth defects was more than 25 times higher than that among other age groups. About half of the children whose deaths were associated with birth defects had cardiovascular system defects, 15% had central nervous system defects, and 12% had chromosomal defects. For deaths associated with genetic diseases, hereditary neurologic or storage disorders were the most common genetic diseases (38%), followed by metabolic disorders (21%), sickle cell and thalassemia (12%). The decline in the rate of mortality from birth defects in the United States probably reflects improvements in medical and surgical care and other factors. Most of the mortality associated with birth defects remains in the pediatric age group (less than 15 years old). The upward trend we detected for the deaths with genetic diseases was most likely related to improved recognition and reporting of some genetic diseases rather than to the increased prevalence.     

Epidemiologic characteristics of conotruncal heart defects in California, 1987-1988

In this population-based case-control study, we explored the association of selected parental and infant characteristics from the birth certificates of children with conotruncal heart defects. We compared 252 cases to a random sample of 5,000 nonmalformed infants from a cohort of 341,839 California live births for 1987-1988. The prevalence of conotruncal defects was 0.732 per 1,000 total births. A decreased risk (OR = 0.55, 95% CI0.33-0.89) for delivering infants with conotruncal defects was found among mothers born in Mexico compared to mothers born in California. An increased risk was observed for Native American mothers compared to non-Hispanic whites (OR = 2.6, 95% CI 1.1-6.0). We also compared risks associated with the individual diagnoses that comprise the group of conotruncal defects. Only minor differences in risk estimates between the anatomic diagnoses were observed, lending support to the methodologic approach of using conotruncal defects as a single category of heart defects in etiologic investigations.     

Anal sphincter defects. Correlation between endoanal ultrasound and surgery

OBJECTIVE: This study was performed to (1) correlate and sphincter defects, identified by endoanal ultrasound with operative findings, and (2) define the appearance of such sphincter defects as seen at operation. SUMMARY BACKGROUND DATA: Endoanal ultrasonography is a minimally invasive method of imaging the anal sphincter complex and enables identification of anal sphincter defects. Little is known about the accuracy and limitations of endoanal ultrasound in identifying such defects. Furthermore, there are no data about the appearances of these endosonic sphincter defects as seen at operation. METHODS: Forty-four patients (40 women; age range, 26 to 80 years; mean age, 56 years) with fecal incontinence, undergoing pelvic floor repair, were investigated by endoanal ultrasound before operation. Endosonic findings were correlated with the appearances of external anal sphincter, internal anal sphincter, and intersphincteric space, at operation. Diagnosis of the site and type of defect was made by macroscopic appearances. Uncertainty about the type of sphincter defect was resolved by obtaining muscle biopsies for histology. RESULTS: All external sphincter defects seen by endoanal ultrasound (n = 23) were confirmed at operation. Twenty-one of 22 internal sphincter defects identified by endosonography also were confirmed at operation. In ten patients with a neuropathic anal sphincter complex, the morphology was normal on endosonography, and this was confirmed at operation. (Sensitivity and specificity of 100% for external anal sphincter; 100% and 95.5%, respectively, for internal and sphincter) CONCLUSIONS: These data show that endoanal ultrasound is an accurate method of identifying anal sphincter defects.     

Accuracy and feasibility of contrast echocardiography for detection of perfusion defects in routine practice: comparison with wall motion and technetium-99m sestamibi single-photon emission computed tomography. The Nycomed NC100100 Investigators

OBJECTIVES: We sought to assess the feasibility and accuracy of myocardial contrast echocardiography (MCE) using standard imaging approaches for the detection of perfusion defects in patients who had a myocardial infarction (MI). BACKGROUND: Myocardial contrast echocardiography may be more versatile than perfusion scintigraphy for identifying the presence and extent of perfusion defects after MI. However, its reliability in routine practice is unclear. METHODS: Fundamental or harmonic MCE was performed with continuous or triggered imaging in 203 patients with a previous MI using bolus doses of a perfluorocarbon-filled contrast agent (NC100100). All patients underwent single-photon emission computed tomography (SPECT) after the injection of technetium-99m (Tc-99m) sestamibi at rest. Quantitative and semiquantitative SPECT, wall motion and digitized echocardiographic data were interpreted independently. The accuracy of MCE was assessed for detection of segments and patients with moderate and severe sestamibi-SPECT defects, as well as for detection of patients with extensive perfusion defects (>12% of left ventricle). RESULTS: In segments with diagnostic MCE, the segmental sensitivity ranged from 14% to 65%, and the specificity varied from 78% to 95%, depending on the dose of contrast agent. Using both segment- and patient-based analysis, the greatest accuracy and proportion of interpretable images were obtained using harmonic imaging in the triggered mode. For the detection of extensive defects, the sensitivity varied from 13% to 48%, with specificity from 63% to 100%. Harmonic imaging remained the most accurate approach. Time since MI and SPECT defect location and intensity were all determinants of the MCE response. The extent of defects on MCE was less than the extent of either abnormal wall motion or SPECT abnormalities. The combination of wall motion and MCE assessment gave the best balance of sensitivity (46% to 55%) and specificity (82% to 83%). CONCLUSIONS: Although MCE is specific, it has limited sensitivity for detection of moderate or severe perfusion defects, and it underestimates the extent of SPECT defects. The best results are obtained by integration with wall motion. More sophisticated methods of acquisition and interpretation are needed to enhance the feasibility of this technique in routine practice.     

Diabetes in primary open-angle glaucoma patients with inferior visual field defects

We reviewed the charts of 144 randomly selected patients with primary open-angle glaucoma who had Aulhorn's stage 1, 2, or 3 visual field defects to investigate whether primary open-angle glaucoma patients with predominantly inferior visual field defects had a higher prevalence of diabetes mellitus than primary open-angle glaucoma patients without such visual field defects. Of the 59 patients with mainly inferior visual field defects in one or both eyes, 19 (32%) had diabetes mellitus, while 11 of 85 (13%) patients without such defects had diabetes mellitus. This difference was statistically significant (P = 0.0096). These results suggest that primary open-angle glaucoma patients with predominantly inferior visual field defects in one or both eyes are more likely to have diabetes and that such patients with no known history of diabetes may benefit from glucose tolerance testing to detect occult impaired glucose tolerance or diabetes mellitus.     

Prediction of outcome of patients with life-threatening ventricular arrhythmias treated with automatic implantable cardioverter-defibrillators using SPECT perfusion imaging

BACKGROUND: In the present study, we examined the predictors of outcome of 103 patients with coronary artery disease and left ventricular dysfunction who had life-threatening ventricular arrhythmias and were treated with implantable cardioverter-defibrillators with the use of single-photon emission computed tomography (SPECT). METHODS AND RESULTS: During a mean follow-up of 29 months, there were 29 cardiac deaths. In comparison with patients who died, survivors had less diabetes mellitus (45% versus 19%, P < .007), higher left ventricular ejection fraction (23 +/- 9% versus 27 +/- 11%, P = .04), and fewer perfusion defects as determined with stress SPECT (15 +/- 5 versus 12 +/- 5, P < .004). Most of the perfusion defects were fixed, indicative of scarring; the extent of reversible defects did not differ (2 +/- 3 in survivors and 3 +/- 4 in nonsurvivors). Multivariate Cox survival analysis identified the number of fixed defects as the only independent predictor of death (chi 2 = 10, P = .002). There were six deaths among 42 patients (14%) with < 8 fixed defects compared with 23 deaths among 61 patients (38%) with > or = 8 defects (P = .005). The 4-year survival was better in patients with < 8 segmental fixed defects than in those with > or = 8 fixed defects (80% versus 36%) (chi 2 = 8, P = .005). CONCLUSIONS: The myocardial perfusion pattern is an important determinant of outcome in patients with life-threatening ventricular arrhythmias who are treated with a implantable cardioverter-defibrillator. The extent of scarring separates patients into high- and low-risk groups with a 2.7-fold difference in death rate.     

Epidemiology and risk factors of wedge-shaped defects in a Swiss population

The purpose of this study was to determine the prevalence of wedge-shaped abrasion defects in the teeth of an adult Swiss population. 980 letters explaining the study were sent to randomly selected subjects. 391 persons (40%) belonging to two age groups (26-30 and 46-50 years) were checked for frequency and severity of wedge-shaped lesions on all buccal tooth surfaces. Furthermore patients were asked about dietary and prophylactic habits as well as other factors possibly relevant to this study. The frequency of severe wedge-shaped defects was 19.1% in the younger, and 47.2% in the older age group, with a mean of 3 affected teeth per person (pooled age group). On average, 34.8% of all patients suffered from tooth hypersensitivity. 84.6% of the examinees with wedge-shaped defects complained of hypersensitivity at these sites. It is concluded that wedge-shaped defects cause considerable problems to more than one third of the population, and that such lesions are often combined with hypersensitivity of affected teeth.     

65Mn钢冷轧起皮缺陷分析与控制

对65Mn钢在轧制过程中起皮缺陷部位进行扫描电镜、金相检验等分析,确定其产生原因。结果表明:铸坯中裂纹是导致长条断续状冷轧起皮缺陷产生的主要原因;气泡和针孔缺陷是导致点状冷轧起皮缺陷产生的主要原因。主要通过优化连铸生产工艺,降低铸坯中裂纹、气泡和针孔缺陷的发生,最终使长条断续状起皮缺陷从1.7%降低到0.04%,点状起皮缺陷得到完全控制,使产品质量得到用户认可。     

冷轧板表面夹杂缺陷成因及控制

针对首钢京唐冷轧板出现的表面夹杂缺陷,在对冷轧板取样电镜分析的基础上,得出铸坯浇铸过程保护渣卷渣以及铸坯中的Al2O3夹杂物是冷轧板条痕缺陷产生的主要原因。通过采取延长RH脱氧合金化后的纯循环时间、采用自动液面控制、取消抖棒操作、选用合适的下渣模式、提高保护浇注效果及提高保护渣黏度等技术措施后,冷轧板的夹杂缺陷得到了有效控制,因夹杂缺陷引起的协议品率由0.83%降至0.30%左右。     

Recurrence risks in offspring of adults with major heart defects: results from first cohort of British collaborative study

BACKGROUND: Congenital heart defects are generally assumed to have a multifactorial aetiology. We have tested this hypothesis by studying adults with heart defects and their families. METHODS: We identified 1094 patients who survived surgery for major cardiac defects before 1970. We chose individuals with disturbance of situs or segmental connection, with atrioventricular septal defect or with tetralogy of Fallot. After exclusion and non-participation, 727 individuals were traced. Each was visited by an investigator and completed a detailed questionnaire. If possible, all "normal" offspring were examined by a paediatric cardiologist. FINDINGS: The 727 individuals had 393 live offspring. There were 71 miscarriages and five terminated pregnancies. Overall, we found recurrent heart defects in 16 liveborn offspring--a recurrence risk of 4.1%. This result differed significantly from sibling risk (2.1%; p=0.021). More congenital heart defects occurred in the offspring of affected women than in those of affected men (p=0.047); when all malformations (cardiac and non-cardiac) in the offspring were taken into account the excess was more significant (p=0.032). We found an excess of miscarriages in the offspring of affected women (p=0.001). In tetralogy of Fallot, heart defects occurred in seven (3.1%) of 223 offspring, 12 (2.2%) of 539 siblings, five (0.3%) of 1575 second-degree relatives, and eight (0.3%) of 2728 third-degree relatives. INTERPRETATION: Our findings do not support a polygenic basis for all heart defects. Atrioventricular septal defect seems to be a single-gene defect and tetralogy of Fallot a polygenic disorder with a small number of interacting genes. Our data suggest that isolated transposition of the great arteries is a sporadic defect.     

Treatment of deep and shallow intrabony defects. A multicenter randomized controlled clinical trial

This prospective multicenter intra-individual randomized controlled clinical trial was designed to compare the efficacy of guided tissue regeneration (GTR) with bioresorbable barrier membranes versus access flap surgery, in intrabony defects. 2 similar defects were selected in each of 23 patients and randomly assigned to 1 of the 2 treatments. Surgery consisted of an identical procedure except for the omission of the barrier membrane in the flap control sites. At 1-year, probing pocket depth reductions were 4.3+/-2.3 mm in GTR treated sites and 3.0+/-1.5 mm in the flap control sites (p=0.02, paired t-test). Clinical attachment level (CAL) gains were 3.0+/-1.7 mm in the GTR sites and 1.6+/-1.8 mm in the control sites (p=0.009, paired t-test). A subset analysis, performed according to the initial depth of the intrabony component of the defects (INFRA), indicated that in shallow defects (INFRA < or =3 mm) treated with the access flap alone, CAL gains were 1+/-1.5 mm, while in deep ones (INFRA > or =4 mm) they were consistently greater (1.9+/-1.9 mm). The % CAL gains, calculated as the % of the baseline intrabony component depth, however, were almost identical in the 2 subpopulations (45.8+/-64.7% in shallow and 43.8+/-37.6% in deep defects). Similarly, in the GTR sites, linear CAL gains were greater in deep (3.7+/-1.7 mm) than in shallow defects (2.2+/-1.3 mm), but no differences were observed in terms of % CAL gains (76.7+/-27.7% and 75.8+/-45%, respectively). The frequency distribution of CAL changes expressed as %s of the baseline INFRA indicates that most of the sites treated with GTR (73% in shallow and 92% in deep defects) gained 50% or more CAL. Furthermore, many defects (64% of shallow and 33% of deep defects) reached 100% of CAL gain. The present study demonstrated that: (i) GTR with bioresorbable barrier membranes resulted in a significant added benefit in comparison with access flap alone; (ii) the linear amounts of CAL gains were greater in deep than in shallow defects; (iii) CAL gains expressed as %s of the baseline depths of the intrabony component, were similar in shallow and deep defects; (iii) the regenerative procedure tested in the present study resulted in CAL gains equal to the depth of the intrabony component of the defect in some, but not in most of the instances.     

Prevalence and types of birth defects in Ontario swine determined by mail survey

Preweaning mortality in piglets constitutes a major loss to the swine industry. Congenital defects account for a small but significant proportion of these losses. To implement appropriate strategies to reduce such losses, it is necessary to identify the specific causes and their relative importance. Consequently, a mail survey of swine production in Ontario was carried out to determine the prevalence and types of birth defects. Statistical comparisons of the prevalence of overall defects were made between accurate and estimate records, breeds (cross vs. purebred), size of operation (number of sows) and geographic location. The mean litter size of 11 pigs born per sow was not significantly different for those with accurate versus estimate records, but the difference in the prevalence of defective pigs (live and dead) was significant (accurate 3.1% vs. estimate 4.1%). Splayleg (spraddleleg) was the most common defect. The next four defects for both groups were belly rupture, other rupture, ridglings and other, but not in the same ranking. Purebred and small farm operations (< 25 sows) had a significantly higher prevalence of birth defects for estimated data only. Geographic location had no effect. Further work is required to determine whether recording prevalence of birth defects in Ontario swine will provide a useful monitor of environmental stress. The study provides a baseline for the prevalence and type of defects in Ontario swine.     

Dual stimulatory and inhibitory effects of fluorine-substitution on mutagenicity: an extension of the enamine epoxide theory for activation of the quinoline nucleus

OBJECTIVE: The incidence and distribution of enamel defects among patients with celiac disease were examined. STUDY DESIGN: The oral cavity was explored in 137 patients with celiac disease (mean age 16.2 years; age range 5 to 68 years) and in 52 control patients (mean age 19.8 years; age range 5 to 64 years). Permanent dentition enamel defects were recorded, along with their number and locations. The decayed, missing, and filled teeth index rates were also established, and an investigation was made of the human leukocyte antigens among the patients with celiac disease. The results obtained were analyzed with the chi-squared test, statistical significance being regarded for p < or = 0.05. RESULTS: Enamel defects were observed in 72 (52.5%) of the patients with celiac disease (52 patients had systematic defects) and in 22 (42.3%) of the control patients (9 patients had systematic defects). Systematic defects were significantly more common in the celiac disease group. In the patients with celiac disease, 72.2% were symmetrical, compared with 40.9% of the defects in the control patients. The incisors were the most frequently affected teeth, the extent of involvement being significantly greater in the celiac disease group. In patients with celiac disease, DR7, DR3, and DQ2 were the most commonly observed human leukocyte antigens. The mean decayed, missing, and filled teeth index rates were 4.8 and 6.2 in the celiac disease group and the control group, respectively. CONCLUSIONS: Enamel defects are common among patients with celiac disease. They tend to be bilateral and symmetrical, and they are chronologically distributed. The lesions affect mainly the incisors and the molars. Patients with such characteristics should be evaluated for possible celiac disease.