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Biomedical subjects

A R Burdi

Publications and source records attributed to A R Burdi.

At least 37 records · Page 2Linked to original sources
PubMed1983

Growth and development of human adipose tissue during early gestation.

805 normal-for-age human embryos and fetuses were used to study early prenatal fat development. The investigation included observations on stages of fat morphogenesis at the light microscopic level and computerized image analyses of fat lobule size and number. The buccal fat pad was selected as a model system for the analyses. Fat tissue differentiates between the 14th and the 16th weeks: there are five morphogenic phases in adipose tissue formation, strongly associated with the formation of blood vessels. Fat lobules are the earliest structures to be identified before typical vacuolated fat cells appear. Concerning fat lobule size and number, we show that after the 23rd week the total number of fat lobules remains approximately constant, while from the 23rd to 29th week the growth of adipose tissue is determined mainly by an increase in size of the lobules. These results suggest that the 14th through the 23rd week is a sensitive period in fat lobule development, and that disturbances of normal adipogenesis during this period may play a role in the etiology of obesity in later life.

Adipose Tissue↗
PubMed1981

Comment on the prune belly syndrome: a 11-week fetus with megacystis.

An 11-week human fetus with megacystis, prostatic dysgenesis, and lateral displacement of the abdominal muscles is described. We suggest that a subtle outflow obstruction of the very early bladder may give rise to both bladder dilation and bladder wall dysgenesis. The bladder dilation may produce abdominal muscle dysplasia or atrophy and almost certainly produces dilation of the prostatic urethra. The dilation of the prostatic urethra disrupts the formation of the prostate.

Abdominal Muscles↗
PubMed1981

Adjacency effects in developmental correlations among tooth organs in human fetuses.

This study explores whether the "distance gradient" model shown for embryonic development and postnatal tooth growth is also characteristic of the fetal period. Histologic data and ratings from 26 human fetuses show that, unlike the embryonic and postnatal periods, changes occurring in two tooth germs are significantly alike, regardless of the number of intervening teeth.

Fetus↗
PubMed1981

Congenital alar field defects: clinical and embryological observations.

Congenital malformations of the nasal ala may occur as isolated unilateral nasal alar defects or as part of more severe facial clefting syndromes. The embryologic significance of the isolated alar deformity seems separate from other craniofacial deformities and justified comment. Clinical examples of isolated nasal alar malformations are correlated with a study of 60 human embryos ranging from seven to 10 weeks gestation. These studies indicate that the nasal and alar developmental fields each have a separate critical time during which cells are most susceptible to altered development.

Female↗
PubMed1979

Crown size-arch space relationships during human prenatal dental development.

As shown in composite reconstructions made from optically-projected measurements of 10mu frontal maxillofacial sections of 20 histologically normal fetuses and embryos in the 70-255 mm CRL range, individual differences in relative tooth size and interdental spacing are evident by 10.5-11 weeks of gestation, and age-corrected crown-size correlations (r=0.40) approximate those in postnatal life. Despite an eight-fold increase in crown dimensions, interdental spacing remains approximately constant after 150 mm CRL, suggesting that the tooth organs or the periodontal membranes are able to maintain spacing, into the third trimester.

Dental Arch↗
PubMed1978

Prenatal growth patterns of the human mandible and masseter muscle complex.

Since experimental and clinical evidence supports some role of musculature in determining the form and size of facial bones during the active periods of growth after birth, this study addresses the same basic relationships between muscle and bone during the periods of active growth before birth. The relationship between the masseter muscle and the mandible, including its ramal and body components, was chosen as the model for study in nineteen human fetuses (ages 16 to 36 weeks). Cross-sectional cephalometric data indicated that, although increases in the size of the muscle and mandible were linearly related to increasing age, the ramal portion of the mandible was more closely related to changes in the masseter muscle than to changes in the mandibular body. Moreover, it appears that reorientation of the muscle anteriorly and downward precedes a similar reorientation of the ramus, with the combination of both fetal events leading to the typical relationships of the two structures expected after birth. Although this study does not get to cause-and-effect relationships, and although the fetal specimens cannot be monitored longitudinally over time, the parallelisms between our prenatal findings and those reported for postnatal periods certainly lend further support to the observation that many aspects of morphogenesis and growth are continual processes spanning the periods on either side of birth.

Body Height↗
PubMed1976

Prenatal origin of brachymesophalangia-5.

As shown in 91 embryos and fetuses in the 41-235 mm crownrump length, brachymesophalangia-5 may be identified in prenatal time. Although the ratios involving different combinations of length of mid-5 relative to other segments yield different frequencies of BMP-5, the short middle segment of the little finger is already associated with clinodactyly and developmental eccentricity as early as the ninth week of prenatal development.

Female↗
PubMed1976

Prenatal origins of carpal fusions.

As shown in 138 embryos and fetuses in the 40-285 mm crown-rump length range, carpal and carpal-metacarpal "fusions" arise from incomplete separation of the cartilaginous precursors rather than from failure of initiation, thus accounting for the "fusions" seen in postnatal radiographs and the grooves that are evident enough in adult fusions. Radiographs selected from over 20,000 apparently normal individuals provide postnatal counterparts for the prenatal examples shown in histological sections.

Carpal Bones↗
PubMed1976

Warfarin-associated embryopathy in a 17-week-old abortus.

Histological and anthropometric studies were made of the hands and face of a 17-week-old (postmenstrual) human fetus that was exposed to warfarin throughout gestation. The fetus had marked nasal hypoplasia and the facial cartilages contained discrete foci of abnormal cartilage. When compared with age-matched control fetuses hand pattern profile analysis showed that the brachydactyly was due to shortening of the terminal phalanges. Histologically chondrogenesis was disordered in the carpals and phalanges, with the most deviant development occurring at the distal ends of the terminal phalanges. In none of the areas of abnormal cartilage was there evidence of hemorrhage or hemosiderin deposition. It is our contention that warfarin is teratogenic in human beings and that its teratogenicity is not due to focal hemorrhage.

Abnormalities, Drug-Induced↗
PubMed1976

Congenital bipartite scaphoid--fact or fiction?

Whether there is such a condition as congenital bipartite scaphoid has long been debated. Five cases that fulfill the established criteria are presented, supplemented by a review of roentgenograms of 17,439 hands in which no case of bipartite scaphoid was detected. Serial sections of 196 fetal hands also failed to reveal any evidence of bipartite development of the scaphoid. We concluded that bipartite scaphoid is of traumatic origin and should be treated accordingly.

Accidents, Occupational↗
PubMed1975

Early prenatal attainment of adult metacarpal-phalangeal rankings and proportions.

As shown in 56 human embryos and fetuses between 15 and 104 mm in crown-rump length, "adult" metacarpal-phalangeal length rankings are attained by the seventh intrauterine week and near-adult bone-to-bone ratios or proportions by the theirteenth week. Micrometric measurements of optically-projected histological hand sections show relative elongation of the distals between the 15-29 mm and 30-44 mm crown-rump range, and relative reduction to radiogrammetrically-determined adult proportions by the 90-104 mm CRL.

Anthropology, Physical↗
PubMed1975

Mandibular precedence in the prenatal development of four permanent teeth.

As shown in 62 pairs of dental opponents from 32 grossly normal human fetuses in the 75-378 mm crown-rump range, mandibular precedence is the rule for 11, 12, C and M1, a trend in agreement with mandibular precedence for deciduous teeth through dm1 and in the gingival emergence of the same permanent teeth during postnatal development.

Humans↗