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Biomedical subjects

D L Rimoin

Publications and source records attributed to D L Rimoin.

At least 109 records · Page 6Linked to original sources
PubMed1989

Odontoid hypoplasia with vertebral cervical subluxation and ventriculomegaly in metatropic dysplasia.

Our experience with 12 patients with metatropic dysplasia has demonstrated two important and treatable complications: odontoid hypoplasia with subluxation of the first and second cervical vertebrae, and ventriculomegaly. Hypoplasia and lack of ossification of the odontoid process were noted in all cases. Subluxation of these two vertebrae was demonstrated in all six patients who had lateral flexion-extension radiographs; three had subluxation even in a neutral position, and sudden odontoid dislocation developed in another after a simple fall. Four individuals have had surgical fusion of the cervical vertebrae; one child died suddenly, 1 week before scheduled surgery. In the three patients in whom computed tomography scans of the head were obtained, enlarged ventricles were found; one had symptomatic increased intracranial pressure and required a shunt. We recommend that odontoid hypoplasia be evaluated in all patients with metatropic dysplasia. If subluxation is proved, atlantoaxial fusion should be performed before damage to the cervical part of the spinal cord results. Serial head circumference measurements and evaluation for hydrocephalus are also recommended.

Adolescent↗
PubMed1989

Diastrophic dysplasia: evidence against a defect of type II collagen.

A description of an abnormal segment-long-spacing crystallite (SLS) pattern has been reported for type II collagen from patients with diastrophic dysplasia (Stanescu et al., 1982 a), a disorder that is characterized by large collagen fibrils in the cartilage matrix. The abnormal SLS consisted of an altered electron density between bands 42 and 45, which was interpreted as an abnormality in the type II collagen molecule. It was suggested that the type II collagen is abnormal in diastrophic dysplasia. We have examined SLS of type II collagen from two patients with diastrophic dysplasia and found the SLS patterns to be identical with that of control type II SLS in almost all micrographs. In a few micrographs of diastrophic SLS, crystallites exhibiting the pattern reported by Stanescu et al. were seen. However, the abnormally patterned crystallites always consisted of dimers that were overlapped at the COOH ends in such a way that an electron dense band of one crystallite was positioned between bands 42 and 45 of the second crystallite, apparently creating the abnormal pattern. The abnormal SLS pattern seen in these cases of diastrophic dysplasia appears to be the result of overlapping crystallites and may not be the result of an intrinsic abnormality of type II collagen. We have constructed histograms of the collagen fibril diameters in diastrophic cartilage. While they are larger than normal collagen fibrils, this by itself does not indicate an abnormality of type II collagen. We have shown that large fibrils such as these can be obtained from normal type II collagen when the structure of the cartilage is disrupted by extraction with guanidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Diseases, Developmental↗
PubMed1989

Quantitative histology of cartilage cell columns in the human costochondral junction: findings in newborn and pediatric subjects.

The mean number of cells per cartilage column and the proportion of hypertrophic and proliferative chondrocytes per column were determined in the costochondral junction in a population of normal subjects including 10 fetal-newborns and 15 subjects aged 0.3-16 y of age. Both the mean number of cells per column and the proportion of proliferative cells per column were significantly greater in the fetal-newborn population compared to the pediatric population (12.6 +/- 1.0 versus 8.4 +/- 0.4, p less than 0.001 and 39.6 +/- 6.9 versus 24.4 +/- 2.5, p = 0.025, respectively) (mean +/- sem [n]). The number of cells per column bore a significant negative relationship to subject age (r = -0.52, p = 0.007). Significant positive correlations were found between the mean number of cells per column and age-specific growth velocity both in males (length-height velocity = [(6.3) (mean number of cells) - 44.1], r = 0.72, p = 0.02) and in females (length-height velocity = [(3.4 (mean number of cells) - 14.4], r = 0.77, p = 0.006). These data will provide normative values against which abnormalities characteristic of the skeletal dysplasias can be compared.

Adolescent↗
PubMed1989

Type II collagen defects in the chondrodysplasias. I. Spondyloepiphyseal dysplasias.

The spondyloepiphyseal dysplasias (SEDs) and spondyloepimetaphyseal dysplasias (SEMDs) are a heterogeneous group of skeletal dysplasias (dwarfing disorders) characterized by abnormal epiphyses, with and without varying degrees of metaphyseal irregularities, flattened vertebral bodies, and myopia. To better define the underlying cause of these disorders, we have analyzed the collagens from costal cartilage from several of these patients, using SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance liquid chromatography (HPLC) of intact chains and cyanogen bromide (CNBr) peptides and amino acid analysis. In almost all of the patients in this study group, the type II collagen exhibited a slower electrophoretic mobility when compared with that in normal controls. The mobility of many, but not all, of the CNBr peptides was also retarded. Peptides near the amino terminus were almost always altered, while the mobility of peptides close to the carboxyl terminus were normal in all but the severely affected cases. Analysis of the CNBr peptides on an HPLC sieving column confirmed that the electrophoretically abnormal peptides were of a higher molecular weight than were control peptides. Amino acid analysis indicated that the abnormal collagens have a higher ratio of hydroxylysine to lysine than does control collagen, suggesting that overmodification may be involved in the altered mobility. Our results are consistent with a defect in the collagen helix that results in overmodification of the molecule from that point toward the amino terminus. We propose that some forms of SED and SEMD are associated with abnormalities in type II collagen that results in delayed helix formation and consequent overmodification of the collagen. Cases of SED fit onto a continuous spectrum of clinical severity that correlates positively with both the extent of alteration and the proximity of the defect to the carboxyl terminus.

Adolescent↗
PubMed1988

A new autosomal recessive lethal chondrodystrophy with congenital hydrops.

Two sibs, the offspring of consanguineous parents, presented with severe short-limb dwarfism and distinct chondro-osseous, radiologic, and histologic appearance. The first sib presented at 30 wk with severe hydrops following fetal death; the second was detected by ultrasonography at 20 wk. Radiologic abnormalities included an unusual "moth-eaten" appearance of the markedly short long bones, bizzare ectopic ossification centers, and marked platyspondyly with unusual ossification centers. Marked extramedullary erythropoiesis was present in both fetuses, and chondro-osseous histology was characterized by marked disorganization of tissue with interspersed masses of cartilage, bone, and mesenchymal tissue. These sibs appear to have a distinct previously unreported autosomal recessive skeletal dysplasia, which can present as hydrops fetalis.

Adult↗
PubMed1988

Achondroplasia with ankylosing spondylitis.

A 41-year-old-white man with achondroplasia has been followed intermittently since age 27. During this time, he has complained of neck and back pain with limited mobility in both. Other problems have included temporomandibular joint pain, dysuria without apparent urinary tract infection iritis, anemia, and an elevated gamma globulin fraction. Recently he returned to the clinic complaining of rigidity of the entire spine. Radiographs showed complete fusion of the sacroiliac joints and fusion of the cervical vertebral bodies and apophyseal joints, consistent with ankylosing spondylitis. He was found to be HLA B-27 positive. This case illustrates the importance of considering other diseases whenever atypical orthopedic problems arise in patients with a bone dysplasia.

Achondroplasia↗
PubMed1988

Metaphyseal chondrodysplasia, Schmid type. Clinical and radiographic delineation with a review of the literature.

Analysis of 20 cases of metaphyseal chondrodysplasia, Schmid type as well as a review of the world literature reveals a specific autosomal dominant disorder that was often over-diagnosed in the past, sometimes resulting in incorrect genetic counselling. Significant radiologic features include an enlarged capital femoral epiphysis in early childhood, coxa vara, greater involvement of the distal femoral metaphysis than the proximal, anterior rib changes and a normal spine. Chondroosseous morphology is not specific. Presentation in nonfamilial cases is no earlier than the second year of life.

Child↗
PubMed1988

Achondrogenesis type I: delineation of further heterogeneity and identification of two distinct subgroups.

Achondrogenesis has traditionally been divided into type I (Parenti-Fraccaro) and type II (Langer-Saldino). We studied the clinical, radiologic, and morphologic features of 17 cases previously diagnosed as achondrogenesis type I to define whether there is even further heterogeneity. On radiographic analysis, two distinct groups of patients were defined based on the presence or absence of rib fractures and ossification of the vertebral pedicles, ischium, and fibula. Two distinct chondroosseous morphologic patterns were observed that directly correlated with the radiographic grouping. One group had round vacuolated chondrocytes with inclusion bodies; the other had collagenous rings around the chondrocytes. We conclude that achondrogenesis type I (Parenti-Fraccaro) consists of two distinct disorders: type IA, which corresponds to the cases originally published by Houston et al. and Harris et al., and type IB, which corresponds to the case originally published by Fraccaro. Analysis of Parenti's case suggests the diagnosis of achondrogenesis type II. All three types of achondrogenesis appear to be inherited as autosomal recessive traits.

Enchondromatosis↗
PubMed1988

Alkaline and acid phosphatase demonstration in human bone and cartilage: effects of fixation interval and methacrylate embedments.

Human bone and cartilage specimens were evaluated for acid and alkaline phosphatase localization following varying fixation periods for fresh or frozen tissue. Formalin fixations of up to 183 hr were followed by embedment in methyl methacrylate; frozen tissue was examined either without fixation or following fixation for up to 1 hr and subsequent glycol or methyl methacrylate embedding. The humeral epiphysis of a young patient with osteogenic sarcoma showed optimum acid and alkaline phosphatase localization following fixation for periods up to 15 hr and embedding in methyl methacrylate. Frozen costochondral junction from a newborn with osteogenesis imperfecta type II showed optimum acid and alkaline phosphatase localization following 30 min fixation in formalin and embedding in methyl methacrylate or after 5 min fixation and embedding in glycol methacrylate.

Acid Phosphatase↗