Pathophysiology of cleft lip muscles following the initial surgical repair.

Muscle biopsy specimens taken from the upper lip and perialar area during the time of secondary lip revision and studied by histochemical techniques demonstrate persistent connective-tissue and muscle abnormalities even at a distance from the cleft margins. Some of these changes are consistent with surgically induced denervation-reinnervation of muscle groups in the surgical field. Increased amounts of connective tissue also were found, most likely secondary to the original deformity and the subsequent surgical procedures. Both these changes may be important factors in subsequent abnormal growth and development of the underlying midfacial structures. This study also demonstrated the resolution of previously noted mitochondrial abnormalities found in the primary cleft lip patient.

Pathophysiology of cleft lip muscle.

Although attention has been focused for decades on the correction of cleft lip deformities, our knowledge about the etiology of such deformities has remained presumptive. Sixty-six muscle biopsy specimens from cleft lip infants were obtained at the time of primary closure. Histochemical stains, histographic analysis, and electron microscopy were performed. A nonneurogenic muscle atrophy was seen that varied in severity, with muscle fibers near the cleft being the most atrophic and disorganized. Muscle fibers stained with the modified Gomori trichrome technique also demonstrated "ragged red" fibers typical of a mitochondrial myopathy. Electron microscopy confirmed large accumulations of mitochondria distorting the fibrils. These mitochondria also were increased in size and densely packed with cristae. This study thus demonstrates that the muscles in cleft lip deformities are not normal. Instead, they reflect either myopathy in the facial mesenchymal mitochondrion or at least a delay in maturation. We hypothesize that some of the morphologic deformities associated with cleft lip may cause a failure of mesenchymal reinforcement of the facial processes at a critical time in development.

Effect of retinoids on the proliferation, morphology and expression of glial fibrillary acidic protein of an anaplastic astrocytoma cell line.

We studied the effect of retinoids on the growth and differentiation of a cell line (U 343 MG-A) derived from a human malignant astrocytoma. Cultures treated with all-trans or 13-cis retinoic acid showed a dose-dependent inhibition of proliferation and a marked reduction in the mean cell number at the plateau phase of growth (3.5 x 10(6) vs. 1 x 10(7) cells/25 cm2) compared with untreated cultures. At confluence, cells treated with all-trans or 13-cis retinoic acid were contact-inhibited, whereas control cultures showed crowding, piling, and overgrowth. All-trans retinol or retinyl acetate did not inhibit growth. Astrocytoma cultures treated with all-trans retinoic acid (10(-6) M) for 5 days were modestly growth-inhibited but by day 16 had the same numbers of cells as controls; cultures that received all-trans retinoic acid for 9 days were markedly growth-inhibited for 7 days after the drug was removed. All-trans and 13-cis retinoic acid (10(-6) M) prevented the EDTA-induced cell detachment seen in control cultures. Strongly adherent all-trans retinoic-acid-treated astrocytoma cells grew at a slower rate than did readily detached all-trans retinoic-acid-treated or control cells. Cell spreading, an increased cytoplasmic:nuclear ratio, and greater numbers of broadly bipolar cells, some bearing thin cytoplasmic processes, were seen in cultures treated with 10(-6) M all-trans or 13-cis retinoic acid. Small tightly packed cuboidal cells and large broadly bipolar cells were seen in astrocytoma cultures from which all-trans retinoic acid was removed on days 5 and 9. Indirect immunofluorescence revealed more intense staining with antiserum to glial fibrillary acidic protein in cultures treated with 10(-6) M all-trans retinoic acid than in control cultures; electron-microscope examination of similarly treated cultures revealed more abundant 8-10 nm intermediate filaments than in control cultures. An enzyme-linked immunosorbent assay showed that all-trans or 13-cis retinoic acid caused a dose-dependent increase in the quantity of glial fibrillary acidic protein in the astrocytoma cells.

Proliferative characteristics of intracranial and spinal tumors of developmental origin.

The proliferative potential of 17 intracranial and spinal tumors (six craniopharyngiomas, four chordomas, three mature teratomas, one immature teratoma, one embryonal carcinoma, one choriocarcinoma, and one dermoid tumor) was assessed. The patients received a 30-minute to 60-minute infusion of bromodeoxyuridine (BUdR) (200 mg/m2 intravenously [IV]) at the time of surgery but before a biopsy of the tumor was performed, to label cells in the DNA synthesis phase. The labeling index (LI) was calculated by determining the percentage of BUdR-labeled cells. The mean LI of the squamous epithelial elements of mature teratomas, craniopharyngiomas, and the dermoid tumor were 3.1 +/- 1.2%, 1.9 +/- 0.9%, and 2.9 +/- 1.9%, respectively. As in normal epithelium, the labeled cells were located in the basal layer. These results and the clinical findings suggest that the proliferation kinetics of these tumors are similar to those of normal skin and differ from those of rapidly growing malignant neoplasms. The other tissue elements (i.e., respiratory epithelium and cartilage) also demonstrated "organized" proliferation patterns similar to those of the corresponding normal tissues. An immature teratoma, an embryonal carcinoma, and a choriocarcinoma each had a high LI (24.6 +/- 5.3%, 32.3 +/- 3.8%, and 17.0 +/- 4.6%, respectively), and no organized pattern of proliferation was observed. In contrast, the mean LI of the four chordomas varied from 1.5% to 5.8%, and there was an even larger variation in the LI of different areas in individual tumors (from less than 1% to 7.5%). This finding suggests that even "slow-growing" chordomas sometimes can be locally aggressive and show a high incidence of recurrence, regardless of morphologic similarities.

High energy phosphate metabolism in experimental permanent focal cerebral ischemia: an in vivo 31P magnetic resonance spectroscopy study.

Relative levels of phosphate metabolites in the brain were examined in vivo by 31P magnetic resonance spectroscopy (MRS) in 50 Sprague-Dawley rats before, during, and after induction of focal permanent cerebral ischemia. After acquisition of baseline spectra, rats were subjected to injury within the core of the MR spectrometer, and 31P spectra were collected for 60 min after injury: in 7 rats, permanent, acute focal cerebral ischemia was induced (ischemia group); in 6 rats, mild hypoxia (FiO2 14%) was induced at the time of the ischemic insult and was maintained for 20 min (ischemia-hypoxia group); in 6 rats, mild hypoxia (FiO2 14%) only was induced for 20 min (hypoxia group). Control studies were performed in 25 rats. Cerebral intracellular pH, calculated from the chemical shift of inorganic phosphate (Pi), decreased immediately after injury in the ischemia and ischemia-hypoxia groups. The first 31P spectrum obtained after injury was characterized by an increase in Pi and a decrease in phosphocreatine (PCr) in the ischemia and ischemia-hypoxia groups; these changes in spectra were significantly greater in the ischemia-hypoxia group. No significant changes in adenosine triphosphate (ATP) were found in either group. Within 60 min of occlusion, 31P spectra returned toward baseline spectra in both ischemia-hypoxia and ischemia groups. No significant changes were seen in spectra of rats subjected to hypoxia alone. These results confirm that 31P MRS is a sensitive measure of early changes of high energy metabolites in focal cerebral ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Foci of MRI signal (pseudo lesions) anterior to the frontal horns: histologic correlations of a normal finding.

Review of all normal magnetic resonance (MR) scans performed over a 12-month period consistently revealed punctate areas of high signal intensity on T2-weighted images in the white matter just anterior and lateral to both frontal horns. Normal anatomic specimens were examined with attention to specific characteristics of this region. Three unique features typify the brain tissues that correspond to the foci of high signal. First, this region of the brain is notable for its loose network of axons with low myelin content. Second, pathologic scrutiny revealed an entity called "ependymitis granularis," which represents patchy loss of the ependyma in the frontal horns with astrocytic gliosis. Third, flow of interstitial fluid within this region of the brain tends to converge at the dorsal-lateral angle of the frontal horns. All these factors contribute to increased water content locally, which results in foci of high signal intensity anterior to the frontal horns in all normal MR scans.

Characterization of normal human brain cultures. Evidence for the outgrowth of leptomeningeal cells.

To establish the histogenetic identity of the predominant cell type in monolayer cultures of normal human adult brain, eight brain specimens were placed into culture and characterized according to cell kinetics, karyotype, antigenic expression, and ultrastructural features. The protein profiles of both the cell layer and the medium were analyzed in selected cultures using sodium dodecyl sulfate polyacrylamide gel electrophoresis and diethylaminoethyl cellulose chromatography. All cultures displayed a limited life span in vitro; marked contact inhibition at confluence; a normal karyotype; an intracytoplasmic and extracellular glycoprotein profile consisting of fibronectin, procollagen type III, laminin, and collagen type IV; specialized intercellular junctions; and interstitial collagen chain synthesis. All of these features were identified in our previous study of human leptomeningeal cultures. The results of immunocytochemical staining for glial fibrillary acidic protein were negative in all cultures of normal human brain, except in early passages in two cultures, which lost the glial cell marker during subsequent passages; immunostains for vimentin were positive in all cells in all cultures. These results support the hypothesis that, in this study, cultures derived from normal human brain are not of glial origin. Our findings also suggest that glial cells are less well-suited to monolayer growth under our culture conditions than are other cell types in enzyme-dissociated brain tissue placed in culture, especially leptomeningeal cells. The identification of leptomeningeal cells as the predominant cell type in normal human brain cultures may prove useful in attempts to foster the growth of human glial cells by culturing brain samples under conditions that prohibit the growth of leptomeningeal cells. Under such conditions, astrocytes, oligodendroglia, and ependymal cells could be isolated with greater ease and cultured separately. These purified cultures of different glial cell types would then provide a more relevant in vitro model for studying human neurological diseases.

An unusual spinal meningioma in a child: case report.

Meningiomas seldom occur in children, and spinal meningioma in a child is rare. We report the case of a boy, 3 years and 5 months of age, who had an unusual atypical meningioma involving the subarachnoid space from T-2 to the cauda equina. To our knowledge, no similar case has been reported previously.