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PubMed2003

Parietal bone agenesis and associated multiple congenital anomalies.

Congenital defects of the calvaria in general and the parietal bones in particular are rare diseases. The latter are of three kinds: 1) cranioschisis, 2) craniodysostosis, and 3) foramina parietalia permagna (FPP). Here, we describe an exceptional anomaly, namely, complete absence of one parietal bone and dysplasia of the other. Agenesis has been reported twice before in the literature. In these cases, the calvarial defect was the only congenital anomaly. In contrast, the patient described in this article exhibited many other congenital deformities, namely, iris coloboma, facial dysmorphism, a large ventricular septal defect of the heart, and a horseshoe kidney. Some of these deformities are associated with neural crest development. Chromosomal analysis was normal in both blood and fibroblasts, and fluorescent in situ hybridization analysis failed to demonstrate a 22q11 deletion as seen in DiGeorge syndrome, a neural crest-related disease complex. Since 2000, the third group of congenital defects of the parietal bones, FPP, has been associated with mutations of the MSX-2 gene. In our case, a genetic analysis of this gene was performed, but no mutations or deletions of MSX-2 were detected.

Abnormalities, Multiple↗
PubMed1995

Subperiosteal implantation of octacalcium phosphate (OCP) stimulates both chondrogenesis and osteogenesis in the tibia, but only osteogenesis in the parietal bone of a rat.

BACKGROUND: It is not known whether long bones and calvaria have distinct biological characteristics. Octacalcium phosphate (OCP), which is a precursor phase of the hydroxyapatite, has been reported to stimulate bone formation if implanted in the subperiosteal region of mouse calvaria. The present study was designed to investigate how the long bone and the calvarium respond to OCP implantation and to compare their biological characteristics. METHODS: The synthetic OCP was implanted into the subperiosteal region of rat tibiae and parietal bones being mixed with bovine type I collagen treated by pepsin (Atelocollagen). The biological response was examined histologically and immunohistochemically for collagen matrix phenotypes of types I and II to identify bone and cartilage formation. RESULTS: Both chondrogenesis and osteogenesis were initiated in the tibia 1 week after implantation of OCP and most of the cartilage was replaced by bone at week 2. However, the parietal bone did not show osteogenesis responding to OCP implantation until week 3, and no cartilage formation was associated with the osteogenesis. CONCLUSIONS: The present study demonstrated the distinct characteristics of biological response to OCP implantation between the long bone and the calvarium in terms of whether or not cartilage formation is involved in the stimulated osteogenesis by OCP, and in terms of timing of the stimulated chondrogenesis and/or osteogenesis, i.e., the parietal bone takes more time to respond to OCP implantation than the tibia.

Animals↗
PubMed2000

Histomorphometry of parietal bones versus age and race.

Surgeons are used to obtaining bone grafts of calvaria, which are abundant and available. The outer table of the parietal bone can be split, usually at the level of the diploic interstice, with an osteotome. Inadvertently violating the inner table and the dura leads some surgeons to avoid using the outer table in the elderly. Sullivan and Smith measured the thickness of the outer tables, diploe, and inner table of 37 cadavers (average age, 59 years) and found each layer to be well preserved distinctly. However, they suggested that calvaria become brittle in patients older than 50 years of age. The current authors hypothesized that diploic composition is not changed, even in the elderly. The thickest part of the parietal bone of 49 Koreans and 30 whites were acquired, and undecalcified slides were made. Via light microscopy, using the National Institutes of Health image, the following measurements were made: the thickness of the parietal bone (PT), outer table (OT), diploe (DT), and inner table (IT); trabecular bone volume percent (TBV); trabecular thickness (TT); and trabecular separation (TS). There was no significant difference in the thickness of the OT, DT, and IT of the PT, TBV, TT, and TS among different ages. The PTs of women were thicker than men's. The PTs of whites were significantly thicker than Koreans'. This study disclosed that the DT is not different among varying age groups and is not sclerosed in the persons older than 80 years, and the OT of these individuals is not brittle. Thus, surgeons do not need to hesitate when taking the OT of the PT in older patients. However, the selection of the site is attentive to PT. The thickest posteromedial part of the PT is favorable and safe as a donor.

Adolescent↗
PubMed1994

Synthetic peptide containing Arg-Gly-Asp inhibits bone formation and resorption in a mineralizing organ culture system of fetal rat parietal bones.

The role of integrins, cell surface receptors involved in cell adhesion to the matrix, was studied in a mineralizing organ culture system. Integrin-mediated cell attachment to matrix proteins has been shown to depend partially on the amino acid sequence Arg-Gly-Asp (RGD), present in the extracellular matrix proteins. Therefore, the effect of RGD peptides on bone formation and resorption was studied in the mineralizing organ culture system derived from 18 day fetal rat parietal bones. Addition of 0.1-50 microM GRGDSPK to bones cultured for 4 days inhibited mineralization in a dose-dependent manner as determined by measuring calcium content and % bone/unit area of tissue. A maximal decrease in calcium content and % bone/unit area of 32.5 and 42.9%, respectively, was found with 50 microM GRGDSPK. With 10 and 50 microM GRGDSPK, bone morphology was dramatically altered, with a disruption of osteoblast and mineralized matrix organization. To assess the effect of the peptides on bone resorption, fetal bones were prelabeled in vivo with 45Ca and resorption was stimulated in vitro with parathyroid hormone in the presence or absence of the peptide. A significant decrease in 45Ca release was found with 10 and 50 microM GRGDSPK. Osteoclast number was also significantly decreased on the bone surface. The peptide was not cytotoxic, since no effect on DNA content, dry weight, or collagen synthesis was found. GRADSP, a control peptide, had no significant effect on mineralization, resorption, or other parameters of bone growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Effect of 1,25-dihydroxyvitamin D3 on prostaglandin E2 production in cultured mouse parietal bones.

1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] was tested for its effects on prostaglandin E2 (PGE2) production and bone resorption in cultured mouse parietal bones. We found that at 24 h 1,25-(OH)2D3 increased 45Ca release but did not affect PGE2 production. However, at 48 h 1,25-(OH)2D3 produced a dose-related increase in PGE2 production. PGE2 production was increased with 1,25-(OH)2D3 at 10(-10)-10(-8) M, and 45Ca release was increased with 1,25-(OH)2D3 at 10(-11)-10(-8) M. The effects of 1,25-(OH)2D3 on PGE2 production persisted in the presence of cortisol (10(-8) M), and the effects were greater in the presence of arachidonic acid (10(-5) M) or fetal bovine serum (10%). Human interleukin-1 alpha (IL-1, 1 ng/ml) and bovine parathyroid hormone-(1-34) (PTH, 10 ng/ml) increased PGE2 production earlier and to a greater extent than 1,25-(OH)2D3. The PGE2 response to IL-1 and PTH was not affected by 1,25-(OH)2D3 at 24 h, but at 48 h 1,25-(OH)2D3 (10(-8) M) increased the PGE2 response to both IL-1 and PTH. The stimulation of 45Ca release at 48 h by high concentrations of 1,25-(OH)2D3, PTH, or IL-1 was similar, and there was no evidence for an additive effect. To test for an effect of 1,25-(OH)2D3 on endogenous IL-1 production, experiments were performed in the presence of an IL-1 receptor antagonist (IL-1Ra, 1000 ng/ml), which has been found to block selectively IL-1 effects on bone resorption and PG production.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Monostotic fibrous dysplasia in the parietal bone: a case report].

In this paper a case of monostotic fibrous dysplasia in the left parietal bone is described. This 51-year-old female was admitted to our hospital for a head injury on January 12, 1983, and a flat, painless hump (7 X 7cm) was incidentally found in the left parietal region. Plain x-ray film of the skull showed a multicystic lesion with slightly sclerotic margin in the left parietal bone, and outward bulging of the outer table without destruction of the inner table in tangential view. CT scan at the level of bone window clearly demonstrated the same abnormality and intradiploic mass separated by some bony septums. Angiography revealed no positive findings, but RI bone scan (99m Tc) showed an abnormal uptake in this lesion. On February 1, 1983, operation was performed to verify the nature of the lesion and for relief of the left-sided headache. Post operative course was uneventful. Histological findings of this mass were of inactive fibrous dysplasia with fibrous tissue replacing the normal bone and surrounded by island or scorlled edge of bones. Monostotic fibrous dysplasia in the cranial vault is rare. It is often possible to make diagnosis in this disease on the clinical course, plain x-ray film and CT scan showing cystic findings and outer table bulging, and RI scan demonstrating abnormal uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Contusions↗
PubMed1989

In vitro mineralization of fetal rat parietal bones in defined serum-free medium: effect of beta-glycerol phosphate.

We have developed a bone organ culture system that mineralizes in vitro. Fetal rat parietal bones (20 days old) were cultured in a chemically defined serum-free medium containing physiological 3 mM phosphate. During 5 days in culture, calcium content increased from 26 to 55 micrograms and dry weight increased from 137 to 194 micrograms. After 2 days in vivo, the calcium content of the parietal bone showed a comparable increase to 49 micrograms and dry weight increased to 183 micrograms. During culture, the mineralized bone area in thick sections increased from 11 to 23%, which paralleled the doubling in calcium content. Fluorescent calcein labeling during the 5 day culture period demonstrated that calcification occurs in an ordered pattern. Protein synthesis was assessed by measuring incorporation of [3H]proline into collagenase-digestible protein (CDP) and noncollagen protein (NCP). The percentage collagen synthesis decreased from 17.5% at 0 time to 5.0% at 2 days and then increased to 9.4% at 5 days of culture. Varying the inorganic phosphate concentration in the medium or adding beta-glycerol phosphate was found to affect mineralization. After 5 days in culture, bones treated with 1 mM phosphate exhibited a large region of unmineralized osteoid with only a 23% increase in calcium content compared with 112% in control (3 mM phosphate) bones and a 28% increase in dry weight compared with a 40% increase in control. Treatment for 5 days with 6 mM phosphate or 1, 3, or 10 mM beta-glycerol phosphate had no significant effect on dry weight compared to control bones. However, bone calcium content increased significantly from 55 +/- 5 micrograms in control cultures to 105 +/- 7 with 6 mM phosphate, 74 +/- 6 with 3 mM beta-glycerol phosphate, and 75 +/- 5 micrograms with 10 mM beta-glycerol phosphate. Calcified area measured by histomorphometry was also significantly greater than in control bones, but this was mainly due to ectopic calcification in the periosteum, representing from 23 to 74% of the total increase in calcified matrix in bones cultured with 6 mM phosphate or 1-10 mM beta-glycerol phosphate. Ultrastructural analysis demonstrated that ectopic calcification was associated with cell death and debris. Therefore, calcification with beta-glycerol phosphate and high concentrations of inorganic phosphate differed from mineralization in vivo or in bones cultured with a physiologically concentration of phosphate.

Calcium↗
PubMed2006

[Suspected non-accidental trauma in children: pseudofracture of the parietal bone].

We reported the case of a three month old child who was suspected of abuse syndrome because of a possible parietal bone fracture during radiographic investigation. At autopsy, the parietal bone abnormalities were not fractures, but proved to be unossified membranous strips. A review of the literature about normal variants of parietal suture on roentgenograms was made to avoid the diagnosis of non-accidental trauma in children, especially in live children where autopsy cannot be made.

Child Abuse↗
PubMed1988

[Benign osteoblastoma of the parietal bones].

Benign osteoblastoma accounts for less than 1% of the primary bone tumors and the calvarial lesion is extremely rare. There are only 12 reported cases in the literature as far as we could collect. We have presented a case of benign osteoblastoma originated from the parietal bone. This 9-year-old boy struck his head on the parietal region and noticed the bulging at the same site. A month later he visited to Fukuoka University Hospital because of persistent bulging of the same site. Neurological examinations were normal. Plain skull roentgenogram on Towne view showed radiolucent area in the midline of parietal bones with irregular margins and in tangential view the outer table revealed thinning and expanding. Coronal CT scan demonstrated same abnormality and intact inner table. The tumor was located within the dipole in the bilateral parietal bones and was removed by a simple curettage. The microscopic feature showed numerous osteoblasts, osteoblastic rimming and many multinucleated giant cells. These indicated a typical benign osteoblastoma. He has been doing well one year after the operation without any evidence of recurrence.

Child↗
PubMed1987

Parietal bone markers of intrauterine growth disturbance.

Old and new data on the size of the human parietal bone are presented. Attention is drawn to zonal changes in the configuration of the bones, particularly in fetuses and newborn babies, that almost certainly indicate phasic variations in the growth rate of the baby, and it is suggested that the estimation of the size of the bone where these abnormal zones occur may be a guide as to the intrauterine age of the child when the alteration in growth occurred. Parietal bone size could also be a help in describing local and general skeletal dysplasias.

Embryonic and Fetal Development↗
PubMedDate not supplied

[A rare case of chondromyxoid fibroma of the parietal bone].

The authors present a very rare case of the chondromyxoid fibroma (CMF) of the parietal bone. This is an uncommon chondroid tumour which constitutes less than 1% of primary bone tumours and which is usually localised in the metaphysis of the long bones, often in the knee region. There are 23 cases of cranial localisation of the chondromyxoid fibroma reported in several papers, 14 cases involved the cranial base and 9 the calvaria. A different ossification process of the skull-base and calvaria is probably responsible for this distribution. In our case we found the focal, lytic lesion in the parietal bone and fibro-greasy tumour mass. The dura was spared. The tumour was removed totally. Curettage of these kind of lesions should be avoided because it may lead to tumour recurrence. Histologically this tumour may cause problems in a differential diagnosis with other chondroid tumours like chondrosarcoma or chondroblastoma.

Adult↗
PubMed1991

A unique case of congenital bilateral absence of parietal bones in a neonate.

The remains of an unidentified female neonate were discovered in a field in central Missouri. Examination revealed bilateral absence of the parietal bones. A search of the literature describing similar defects suggests that the present case represents a unique condition, described here for the first time.

Female↗
PubMed2003

Statin collagen grafts used to repair defects in the parietal bone of rabbits.

We compared the amount of new bone produced by statin collagen grafts with that produced by collagen grafts. Fifteen bone defects were created in the parietal bone of nine New Zealand White rabbits. In the experimental group, five defects were grafted with simvastatin dissolved in water for injection mixed with absorbable collagen sponge. In the control groups, five defects were grafted with water for injection mixed with absorbable collagen sponge alone (active control) and five were left empty (passive control). Animals were killed on day 14 and the defects were prepared for histological assessment. Serial sections were cut across the whole defect. Quantitative analysis of new bone formation was made on 100 sections using image analysis. A total of 308% more new bone was present in defects grafted with statin collagen grafts than those grafted with collagen grafts alone (P<0.0001). No bone was formed in the passive control group. In conclusion, statin collagen grafts were osteoinductive and can be used as a material for bone grafts.

Animals↗
PubMed2005

Chondromyxoid fibroma of the parietal bone.

We report the case of an 11-year old girl who presented with an intracranial chondromyxoid fibroma arising from parietal bone. Chondromyxoid fibroma is a benign cartilaginous neoplasm, which can be easily mistaken for chondrosarcoma, especially in small biopsies. It is more common in long bones and is least common in cranial bones. Published work describes about 33 cases occurring in cranial bones with almost equal incidence in the bones of the base of the skull and cranial vault. To our knowledge, this is the second case of chondromyxoid fibroma reported to occur in parietal bone and is the first case reported in an English-language journal. We present this case for its rare anatomical, clinical, radiological and histological presentations.

Child↗