Purification and expansion of human Schwann cells in vitro.

The ability to culture cells from the human nervous system provides new insight into the pathophysiology of neurological diseases and could be crucial to the development of gene replacement therapies and neural transplantation. We report that the proliferation of human Schwann cells isolated from paediatric and adult nerves is sustained in vitro by recombinant glial growth factor. Agents that increase intracellular cyclic cAMP were also mitogenic towards Schwann cells but suppress growth of contaminating fibroblasts. As the lifespan of highly enriched cultures can be extended for up to twelve population doublings, large numbers of cells can be generated from nerve biopsies.

Nasopharyngeal profile and velopharyngeal valve mechanism.

Proper management of velopharyngeal insufficiency requires an understanding of normal velopharyngeal anatomy and function. The present cephalometric study correlates the nasopharyngeal profile at rest with velopharyngeal function as observed by nasendoscopy and fluorographic and videofluoroscopic studies. Fifty-two normal individuals and 23 patients with insufficient velopharyngeal valves were examined. A correlation was found between nasopharyngeal profiles at rest and the closure patterns of the velopharyngeal valve. It was found that when existent, Passavant's ridge is subsequently formed where thick soft tissue corresponding to the superior constrictor muscle is found beneath the mucosa of the posterior pharyngeal wall at rest. Our conclusion is that Passavant's ridge is formed by the superior constrictor. The present study represents additional confirmation that differences in velopharyngeal closure patterns are the result of differences in anatomy. A biomechanical model of velopharyngeal valving is presented based on individual spatial muscular orientation and the hierarchical recruitment of the velopharyngeal muscles. This recruitment is progressive and is dependent on the effort required to achieve tighter velopharyngeal sealing.

The otolaryngologist and the patient with velocardiofacial syndrome.

Velocardiofacial syndrome is the most common syndrome associated with clefting of the secondary palate. The endoscopically diagnosed occult submucous cleft palate is the most common palate anomaly associated with this syndrome. Patients with velocardiofacial syndrome present a special challenge to the otolaryngologist, who must be familiar with the diagnostic and therapeutic aspects of this syndrome. We report the findings in 21 patients with velocardiofacial syndrome. Only 11 (52%) had the typical manifestations, and others had only partial phenotype. Adenoidectomy must be avoided in these patients, since undiagnosed occult and overt submucous cleft palate are the most common cause of velopharyngeal insufficiency after adenoidectomy. Three patients had aberrant carotid arteries. This anomaly must be excluded by nasoscopy and computed tomographic scanning before pharyngeal flap surgery is considered in these patients. Criteria for exclusion of high-risk patients from adenoidectomy are presented and discussed.

Evaluation of new diagnostic imaging technologies.

New imaging technologies have to be evaluated for safety and for utility taking into account the uniqueness of the biological feature examined, the quality of the anatomical visualization, and accuracy of diagnosis. Comparative studies establish whether the new technology complements or replaces older methods, and what contribution it makes to therapeutic strategies. Historically, there were three phases: that of the great lone innovators, from whose efforts new techniques diffused; that of the large cooperative studies by academic clinicians and, recently, with the advent of MRI (magnetic resonance imaging), the phase of publicly appointed assessors, such as the FDA (Food and Drug Administration, USA). The methods of the latter two are detailed and critically compared. Evaluation in the clinical setting is more comprehensive. Therapeutic benefit, and not just image quality, has to be the ultimate consideration.

Primary CT diagnosis of gastrointestinal masses.

Four cases of gastrointestinal masses (3 tumorous and 1 inflammatory) diagnosed primarily by CT, are presented. It is stressed that the radiologist should be familiar with the CT appearance of these conditions. It is recommended that in most cases barium studies and endoscopy should follow. Case 4 is unique because it represents the rare possibility of CT diagnosis of a tumor of the bowel where barium studies and endoscopy may have failed.

The cholecystectomy sonographic pseudolesion.

A frequent right upper quadrant postcholecystectomy pseudolesion is described together with the features which distinguish it from true lesions of the region.

CT diagnosis of left atrial thrombus undiagnosed by echocardiography.

Although effectiveness of CT scan in the diagnosis of intracardiac masses is considered limited by heart pulsations, it may be effective in diagnosis of lesions not detected by echocardiography. This report presents a case where a large left atrial thrombus which was undiagnosed by 2D echocardiogram was diagnosed by CT scan.

CT findings in chronic post-thrombotic obstruction of the inferior vena cava.

Four patients suffering from chronic post-thrombotic inferior vena caval obstruction were examined by CT scan. The CT appearance of the various venous collateral channels is presented. Other findings observed were bulky seminal vesicles and bilateral compressed bladder. Two unique findings for this entity were observed: 1) the disappearance of the long-since thrombosed IVC, or as we refer to it, the "lonely aorta" sign; and 2) absence of the posterior low-density area of the liver on the unenhanced cuts, representing the hepatic segment of the IVC. This noninvasive method facilitates differentiation among chronic post-thrombotic occlusion of the IVC, acute thrombosis, tumor thrombosis, and occlusion by tumor compression.

Retrograde flow in the left gonadal vein at abdominal angiography: an anatomo-physiological review and clinical assessment.

Retrograde flow in the left gonadal vein may be visualized in the venous phase of aortography or renal arteriography. In none of 13 cases was this due to a mass lesion at the renal hilum. Although the Valsalva maneuver may cause this flow reversal in some, in most cases it is due to anatomical structures or variants compressing the renal vein. These are detailed. Left gonadal vein reflux incidentally detected on the aortogram may thus indicate impaired left renal venous drainage and its consequences. There are also clinical and urographic constellations which merit aortography to detect left gonadal vein reflux for their elucidation.

Inspiration chest radiography by lateral recumbency.

In lateral recumbency the uppermost lung is in a state of relative inspiratory apnoae. This physiological phenomenon may be exploited to obtain inspiratory chest films in children and uncooperative adults and as an improvement on the sitting film of patients unable to stand. It also tests to some extent the pulmonary compliance and the mobility of the diaphragm.

Early angiography in the management of post-renal biopsy hematuria.

A case is reported in which the value of early angiography in the management of post-renal biopsy hematuria is exemplified. The decision of whether treatment should be conservative or surgical is based on the precise anatomical delineation of the cause of hematuria and the chances of spontaneous remission. When necessary an operation guided by the angiogram can be limited to partial resection of the lesion-bearing region.

Intrapetrous epidermoid deforming the pantopaque cisternogram.

Pantopaque cisternography is now an established procedure for the diagnosis of mass lesions arising in, or extending into the cerebellopontine angle. Non-filling of the internal auditory canal, even if of normal dimensions, is, with rare exceptions, diagnostic of an intracanalicular acoustic neurinoma. A case is reported of an intrapetrous epidermoid excavating the internal ear, but not widening the meatus, which prevented filling of the canal at cisternography.

A new symdrome of left vocal cord paresis and esophageal diverticulum due to mediastinal fibrosis.

The association of left vocal cord paresis with an esophageal diverticulum pointing to the left at the aorto-bronchial level constitutes a syndrome resulting from mediastinal fibrosis in that region. Demonstration of this type of diverticulum in a case of unexplained left cord paresis establishes mediastinal fibrosis as its cause.