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Factors affecting risks of congenital malformations. II. Effect of maternal diabetes on congenital malformations.

The effect of maternal diabetes on the risk of congenital malformations was investigated in 23,695 pregnancies of white mothers, inclucing 339 patients of the Joslin Clinic, and in 24,742 pregnancies of Negro mothers, drawn from the prospective Collaborative Perinatal Project. Of these, 372 mothers had gestational diabetes and 567 had overt diabetes (before and during pregnancy). Pregnancy outcomes studied included stillbirths and live births. Among core women (excluding the Joslin Clinic cases), the frequencies of diabetic pregnancies were 1.31% and 1.18% for white and Negro mothers, respectively; in both groups, approximately two thirds of these pregnancies had gestational diabetes. There was no increase in malformation risk in the pregnancies of mothers with gestational diabetes over that of nondiabetic mothers in either racial group. However, the risk of malformation for white mothers with overt diabetes was double that of nondiabetic mothers for both major and minor categories of malformations. The incidences of major and minor types of malformations in the pregnancies of white mothers with overt diabetes were 17.94% and 10.94%, respectively, compared to the corresponding incidences of 8.34% and 6.25% for the white nondiabetic group. In Negro mothers with overt diabetes, a smaller increase of risk was seen only in major malformations; the incidences were 13.64% and 8.45% for the diabetic and nondiabetic groups, respectively. The increased risks for malformations were distributed generally throughout the organ systems. Multiple malformations occurred more frequently in the overt diabetic than in the nondiabetic group, suggesting that maternal diabetes must act adversely an an early stage of fetal development. Two cases with the caudal regression syndrome were observed in children of diabetic mothers, whereas none was found among births from nondiabetic mothers. Insulin (or analog) therapy of diabetes neither decreased nor increased the risk of malformation in the fetus. However, duration of diabetes had a significant effect on the malformation risk: the longer the mother had the disease, the higher was the incidence of malformations in the fetus. Paternal diabetes did not contribute to increase in risk. These observations suggest that maternal diabetes per se, through its adverse effects on maternal metabolism, is the responsible factor for the increase of malformations in the offspring.

Central Nervous System

Factors affecting risks of congenital malformations. I. Analysis of epidemiologic factors in congenital malformations. Report from the Collaborative Perinatal Project.

An analysis was made of over 30 demographic, biologic and medical variables in relation to risks of congenital malformations which occurred in the Collaborative Perinatal Project. The study population consisted of 46,689 single and multiple live births and fetal deaths about whom complete information was available on all study variables. Included in the analysis were 5 general malformation categories, 27 specific major, and 7 specific minor malformations. Several new associations were detected between epidemiologic factors and risks of specific malformations while other previously reported associations were confirmed by the present investigation. The analysis of general categories of malformations showed that multiple births had a higher frequency of major malformations than single births; whenever sex differences in incidence were noted, males, with few exceptions, had an excess of malformations over females; and maternal diabetes during pregnancy was associated with increased risk of major malformations in the fetus. Among specific findings of possible etiologic significance were that the risk for microcephaly was associated with infrequent prenatal visits and the presence of maternal hyperthyroidism; and unusually low weight gain and infrequent prenatal visits were associated with increased risk for lung hypoplasia. There was no significant effect of inbreeding of the fetus or mother on the risks of general or specific types of malformations. Anencephaly was more frequent among white than among Negro infants, whereas no difference in incidence was noted in spina bifida between the two racial groups. This finding points to an inconsistency in the hypothesis of common etiology for these malformations. Whites were also found to have significantly higher incidences over Negroes of pyloric stenosis, congenital dislocation of the hip, micrognathia, and pectus excavatum, while Negroes have higher incidences of metatarsus varus and inguinal hernia.

Cataract

Congenital cystic malformation of the lung. A form of congenital bronchiolar ("adenomatoid") malformation.

Of 41 cases of cystic lungs in children, 21 were found by microscopy to be due to congenital cystic malformation. In most of the remainder, chronic inflammation and fibrosis precluded differentiation from postinflammatory pneumatocele. A few were intermediate between cystic malformation and congenital lobar emphysema. The cystic malformations were 17 surgical and four necropsy specimens, and two thirds of the patients were under 1 year old. The condition was unilobar, and the cysts were thin-walled, up to 8 cm in diameter, multiple or multilocular, and microscopically resembled proliferated, dilated bronchioles communicating with alveoli. There was a wide range of size, shape, and number of cysts, and no sharp demarcation from adenomatoid malformation in stillborn infants. Thus, bronchiolar malformations fall into two overlapping clinicopathologic groups: (1) adenomatoid malformation in edematous stillborn and premature infants with perdominantly solid lobes showing more epithelial proliferation and immature terminal airways and (2) cystic malformation in term infants and children with predominantly cystic lobes and interspresed mature alveoli.

Bronchi

Ocular malformations in human fetuses with external malformations.

Sixty undamaged human fetuses with various nonocular external malformations were selected randomly from a large number of fetuses collected by the Department of Anatomy Faculty of Medicine, Kyoto University, and examined macroscopically and stereomicroscopically for ocular and other external and internal malformations. Eighteen fetuses (30 percent) showed ocular malformations of the following types: approximated eyes (two cases), approximated eyes plus microncornea (one case), microphthalmia (eight cases), microcornea (three cases), corneal opacity (one case), transparent sclera (two cases), and antimongoloid obliquity of the palpebral fissure (one case). In addition, asymmetric insertion sites of the recti muscles, regarded as a minor deviation, were found in 12 cases (20.0 percent). Of the fetuses with malformations in the central nervous system 37.5 per cent showed ocular malformations. No specific causes of ocular malformations could be confirmed in the present study. However, drugs such as hormones, sedatives and antipyretics in the early stage of pregnancy, systemic diseases such as influenza, and dysplasia or dysfunction of the ovary or uterus might be related to the production of some ocular and other malformations.

Abnormalities, Multiple

Electrocardiographical investigations of normal and malformed embryo and foetus hearts in humans, mammals, and avians. Electrocardiographical investigations of the experimentally malformed heart of the chick foetus.

The experimental technique was based on the injection of a 0.5 % Janus green B solution into the embryonic pharynx through a branchial slit, at the age of three days. This method of chemical endocauterization of the pharynx was elaborated by B. Menkes. Our experimental method produces a necrotizing intoxication of an extracardiac region (the region of the branchial arches) and cardiovascular malformations similar to those observed in human pathology have been obtained. This experimental group consisted of chick foetuses of 9 -- 11 days; their interventricular septation is normally fulfilled at the end of the 8th day of incubation. 342 foetuses with or without cardiovascular malformations have been examined by electrocardiography and 678 electrocardiographs have been recorded. Normal electrocardiographs of chick embryos were similar to those recorded in mammal and human embryos. The probability of a cardiovascular malformation could be assumed by direct electrocardiography in a proportion of 80 -- 85% while indirect electrocardiography could allow the diagnosis in a proportion of only 60 %. There are no pathognomonic electrocardiographs for a certain type of malformation, but the grouping of certain alteration of the electrical recording can suggest the existence of a cardiovascular malformation. Electrocardiographs recorded with experimentally malformed hearts recall the patterns of human foetal pathology.

Animals

Induced and genetic mouse middle ear ossicular malformations: a model for human malformative ossicular diseases and a tool for clarifying their normal ontogenesis.

Oral administration of 13-cis retinoic acid (RA) to pregnant mice on the 9th gestation day provokes important malformations of the middle ear ossicles, associated with a general kind of craniofacial dysmorphogenesis evoking the human mandibulofacial dysostosis. The malleus, incus and stapes are affected. The malleus exhibits a handle separated from its head and keeping a persistant relationship with the tubotympanic recess. The stapes makes no contact with the otic capsule. The malformation pattern is visible early as shown by the appearance of an abnormally curved Meckel's cartilage at day 12, followed by the development of atypically shaped ossicular anlagen. The mouse "far" (first arch malformation) mutation is responsible for minor ossicular abnormalities which disrupts the normal relationships between the stapes, Reichert's cartilage and stapedial muscle. The administration of RA to pregnant mice and the comparison with a genetically induced malformation (the mutation far) provides some interesting information about the postulated mechanisms of human middle ear dysmorphogenesis, as well as precious data about the features of normal ossicular primordia formation. The comparison of these features with human middle ear abnormalities as revealed by medical imaging sheds light on human malformation patterns and provides a better understanding of normal and abnormal radiologic ossicular aspects.

Abnormalities, Drug-Induced

Improved ascertainment of cardiovascular malformations in infants with Down's syndrome, Atlanta, 1968 through 1989. Implications for the interpretation of increasing rates of cardiovascular malformations in surveillance systems.

Several birth defects surveillance systems have shown an upward trend in the birth prevalence of several congenital cardiovascular malformations. Improvements in clinical ascertainment have been suggested as an explanation for this increase. For several decades, 40-50% of infants with Down's syndrome have been reported to have cardiac defects associated with the unbalanced genotype. Therefore, secular changes in the frequency of ascertained cardiovascular malformations among infants with Down's syndrome in surveillance systems could shed light on improvements in the ascertainment of these defects. The authors examined changes in the frequency of ascertained cardiovascular malformations among 532 cases of Down's syndrome recorded in the Metropolitan Atlanta Congenital Defects Program from 1968 through 1989. Overall, 33% of the cases have reported cardiovascular malformations. However, the frequency of these defects in Down's syndrome infants increased dramatically from about 20% in the early 1970s to more than 50% in the late 1980s (p = 0.0001). This upward trend was seen for all major categories of cardiac defects and persisted after the cases were stratified by race, sex, maternal age, hospital of birth, birth weight, and gestational age. These results show improvement in the ascertainment of cardiovascular malformations among Down's syndrome infants in a surveillance population. They are also consistent with the hypothesis that the increasing rates of cardiac defects are related, at least in part, to improved ascertainment of these defects in the population.

Down Syndrome

Frequent coexistence of ocular malformations in externally malformed human fetuses.

60 undamaged human fetuses with some types of external malformations were taken from the human embryo and fetus collection at the Department of Anatomy, Kyoto University. They were examined macroscopically and stereo-microscopically for ocular and other external and internal malformations. 18 cases, that is 30% of the group, showed ocular malformations of the following type: approximated eyes (2 cases), approximated eyes + microcornea (1), microphthalmia (8), microcornea (3), corneal opacity (1), transparent sclera (2), antimongoloid obliquity of the palpebral fissure (1). In addition, asymmetric insertion site of the recti muscle(s) which can be regarded as a minor deviation, was found in 10 cases (16.7%). Other types of malformations were found simultaneously in a variety of organ systems and regions. No particular maternal factors were suggested to be related to such coexisting ocular malformations.

Abnormalities, Multiple

Split cord malformation: Part I: A unified theory of embryogenesis for double spinal cord malformations.

Much confusion still exists concerning the pathological definitions and clinical significance of double spinal cord malformations. Traditional terms used to describe the two main forms of these rare malformations, diastematomyelia and diplomyelia, add to the confusion by their inconsistent usage, ambiguities, and implications of their dissimilar embryogenesis. Based on the detailed radiographic and surgical findings of 39 cases of double cord malformations and the autopsy data on two other cases, this study endorses a new classification for double cord malformations and proposes a unified theory of embryogenesis for all their variant forms and features. The new classification recommends the term split cord malformation (SCM) for all double spinal cords. A Type I SCM consists of two hemicords, each contained within its own dural tube and separated by a dura-sheathed rigid osseocartilaginous median septum. A Type II SCM consists of two hemicords housed in a single dural tube separated by a nonrigid, fibrous median septum. These two essential features necessary for typing, the state of the dural tube and the nature of the median septum, do not ever overlap between the two main forms and can always be demonstrated by imaging studies so that accurate preoperative typing is always possible. All other associated structures in SCM such as paramedian nerve roots, myelomeningoceles manqué, and centromedian vascular structures frequently do overlap between types and are not reliable typing criteria. The unified theory of embryogenesis proposes that all variant types of SCMs have a common embryogenetic mechanism. Basic to this mechanism is the formation of adhesions between ecto- and endoderm, leading to an accessory neurenteric canal around which condenses an endomesenchymal tract that bisects the developing notochord and causes formation of two hemineural plates. The altered state of the emerging split neural tube and the subsequent ontogenetic fates of the constituent components of the endomesenchymal tract ultimately determine the configuration and orientation of the hemicords, the nature of the median septum, the coexistence of various vascular, lipomatous, neural, and fibrous oddities within the median cleft, the high association with open myelodysplastic and cutaneous lesions, and the seemingly unlikely relationship with fore and midgut anomalies. The multiple facets of this theory are presented in increasing complexity against the background of known embryological facts and theories; the validity of each facet is tested by comparing structures and phenomena predicted by the facet with actual radiographic, surgical, and histopathological findings of these 41 cases of SCM.

Adolescent

Median facial malformations and their implications for brain malformations.

For purposes of identifying craniofacial syndromes which predict brain malformations the face can be regarded as developing from 2 sources. The median and paramedian structures derive from the embryonic segment of the face, termed the frontonasal prominence. The lateral structures of the face derive from the branchial arches. Certain patterns of median plane facial anomalies predict a severe brain malformation, while other patterns, although producing equally grotesque facial malformations, bear little association with a malformed brain. Orbital hypotelorism may occur in a variety of syndromes with microcephaly. When combined in typical patterns with other median plane facial defects, the patient almost certainly has holoprosencephaly, and has a poor prognosis for useful psychomotor development and survival. To the current knowledge of the author, every patient with orbital hypotelorism and total aplasia of the intermaxillary segment has a severely malformed brain. These patients, with only a rare exception, make no useful psychomotor progress and die in infancy. Orbital hypertelorism implies an increased risk of a neurologically abnormal patient, but neither the mental deficiency nor the prognosis for survival are as poor as in hypotelorism. When hypertelorism is combined with certain median plane facial anomalies the patient has the median cleft face syndrome and most likely has normal mentality, or only mild retardation, and has a normal prognosis for survival.

Abnormalities, Multiple

Dealing with suspicions of malformation frequency increase. Experience with the Swedish register of congenital malformations.

Strategies in dealing with data obtained from malformation monitoring based on experiences with the Swedish monitoring systems, operating since 1965 (Register of Congenital Malformations) and 1973 (Medical Birth Register) are discussed. The importance of checking data that have sounded an alarm is stressed. Experience has shown that false alarms due to artefacts, such as changed diagnostic routines, changed reporting or registration of malformations, or random fluctuations, comprise most suspected changes in incidence. If a true increase in malformation frequency or a local cluster is observed, a hint of possible aetiological factors can be obtained from studies of maternal age distribution, seasonal viriation, geographical distribution, etc. The last step of the analysis consists of a case-control or a cohort study, aimed at revealing a specific teratogen. The importance of locating limited research resources to well-defined problems using high quality data is stressed.

Abnormalities, Drug-Induced

Comparison of the clinical presentation of symptomatic arteriovenous malformations (angiographically visualized) and occult vascular malformations.

The authors compared the clinical presentations of angiographically apparent arteriovenous malformations (AVMs) and angiographically occult vascular malformations (AOVMs) of the brain in 188 consecutive patients treated when computed tomography and magnetic resonance were available. There were 133 patients (70.7%) with AVMs and 55 patients (29.2%) with AOVMs. AOVMs tended to occur more frequently in male patients and in the posterior fossa and to present earlier clinically than AVMs, but differences were not significant. One distinctive feature was the greater size of AVMs, as compared with AOVMs. Presentation by hemorrhage occurred in 64.3% of the patients with AVMs and in 61.8% of those with AOVMs. Malformations of both types located in the posterior fossa presented with hemorrhage more frequently (84.2% of AVMs and 78.5% of AOVMs) than similar lesions lying above the tentorium (60.8% of AVMs and 56% of AOVMs). Bleeding was more severe in patients with AVMs than in those with AOVMs, as indicated by the higher mortality associated with hemorrhage (7.5 vs. 3.6% of the cases) and the more frequent and marked decrease in the level of consciousness observed at admission (34 vs. 16.2% of drowsy or comatose patients). Brain hematomas caused by AVMs were on average bigger than those caused by AOVMs (58.8 and 20% of large hematomas, respectively), and intraventricular and subarachnoid hemorrhages were also more common and profuse in patients with AVMs. However, AOVMs bled subsequently more times than AVMs (61.7 vs. 15.6%), before they were diagnosed and treated, leading to a higher nonoperative morbidity (16.3 vs. 13.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Limitations of the OPCS congenital malformation notification system illustrated by examination of congenital malformations of the cardiovascular system in districts within the Trent Region.

Data are presented from OPCS notification statistics and other sources on rates of congenital cardiovascular malformations in the Trent Health Region and in its constituent Districts. While Trent in general, and some of its districts in particular, show high notification rates, other data sources suggest that the underlying malformation rate may not be raised compared with that seen nationally. Reasons for this discrepancy are discussed and the OPCS notification system is compared with that in Scotland.

Heart Defects, Congenital

Cardiovascular malformations associated with congenital anomalies of the urinary system. Observations in a series of 453 infants and children with urinary system malformations.

Thirty-four (8%) of 453 infants and children with urinary system malformations had cardiovascular malformations. Cardiac defects were seen frequently in Potter syndrome, unilateral renal agenesis, and horseshoe kidney. The most frequently encountered types of heart defects were ventricular septal defect (33%), endocardial cushion defect (15%), tetralogy of Fallot (12%), and patent ductus arteriosus (12%).

Abnormalities, Multiple

Studies of malformation syndromes of man XXXIX: a craniosynostosis-craniofacial dysostosis syndrome with mental retardation and other malformations: "craniofacial dyssynostosis".

We report clinical findings in 2 sisters and 5 sporadic cases with a "new" type of craniosynostosis/craniofacial dysostosis and shortness of stature. Premature closure of lambdoid sutures and posterior part of sagittal suture causes a posteriorly narrow, dolichocephalic skull with small, flat or bulging occiput and protuberance of the forehead; disturbance of the growth of basal skull structures leads to craniofacial dysostosis and (secondary) anomalies of the face. In one patient the coronal suture was also involved. One of the patients had a congenital heart defect. Four untreated patients had mental retardation; 3 had craniosynostectomy with more or less normal psychomotor development afterwards. Some patients had hydrocephalus and 1 had a brain malformation (agenesis of the corpus callosum with presumed interventricular lipoma). The observation of sisters with the same condition suggests autosomal recessive inheritance. This etiologic hypothesis is supported by the fact that 4 of 7 patients are of Spanish, Mexican, or Puerto Rican ancestry; this population probably has a rather high gene frequency and the trait should be relatively common in areas occupied by this population and their descendents. The condition has been designated craniofacial dyssynostosis.

Abnormalities, Multiple

[Double malformation discovered during investigations for hypertension; single pelvic kidney and occipitovertebral joint malformation (author's transl)].

A young Portuges eman with a spastic gait was found to have a kidney lying below the bladder. This was the only kidney present and its blood supply was derived from a renal artery which was also the only one present. This renal abnormality was associated with a major malformation of the occipitovertebral joint (occipitalization of the atlas, total occipito-atlanto-odontoid dissociation above the line of the digastric). The possible relationship between these two affections is discussed.

Abnormalities, Multiple