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P Franz

Publications and source records attributed to P Franz.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Malignant transformation of a peripheral nerve sheath tumor in the area of the paranasal sinuses].

BACKGROUND: Distinguishing schwannoma from neurofibroma of the paranasal sinuses can be difficult. PATIENTS: We present the rare case of malignant peripheral nerve sheath tumor of the frontoethmoid complex that occurred in a patient who had suffered from schwannoma at the same site 7 years before. The tumor was examined clinically, histologically, and immunohistochemically. RESULTS: Although complete surgical excision of the primary tumor should have been an apparently adequate management for benign schwannoma, the tumor recurred and even metastasized into the brain. The tumor was resistant to aggressive surgical therapy combined with adjuvant irradiation and gamma knife therapy. The results of histological examinations identified schwannian features of the primary tumor and clearly outlined differentiation to solitary neurofibroma. CONCLUSIONS: Considering that schwannomas can be predominantly benign with foci of malignant areas and that there are reported cases of malignant transformation of benign schwannomas, the present consensus in management of small and low-grade malignant schwannomas is complete surgical excision with negative margins. The therapy of choice for high-grade malignant schwannomas is aggressive surgical resection, with wide tumor free margins, combined with adjuvant irradiation and chemotherapy.

Aged↗
PubMed1996

Localization of nitric oxide synthase I and III in the cochlea.

Nitric oxide synthase (NOS) isoforms I and III were localized in the guinea pig cochlea by indirect immunohistochemistry using frozen sections and paraffin sections. NOS I staining was observed in the cytoplasm of outer hair cells, in nerve cell somata and fibers of the spiral ganglion, and in axonal profiles of the spiral lamina next to the base of inner hair cells. In addition, lining cells of the inner sulcus and limbus, and cells of the spiral ligament stained for NOS I but vascular walls remained unstained. NOS III reactivity was seen in the cytoplasm of outer and inner hair cell, in lining cells of the limbus, and on the endolymphatic surface of marginal cells. Staining for NOS III of spiral ganglion perikarya showed varying intensity. Endothelial cells of cochlear glomeruli reacted for NOS III. NOS III in vascular endothelial cells implies regulatory effects of nitric oxide (NO) on vascular wall tonus and cochlear blood supply. NOS I in cochlear neurons indicates these cells as possible sources for NO during neuronal activity. Activated neurons may provide NO that adjusts cochlear perfusion to neuronal activity. Finally, NO that is liberated from hair cells or afferent synaptic terminals may act as an inhibitor on N-methyl-D-aspartate (NMDA) receptors (negative feed-back inhibition).

Animals↗
PubMed1994

[Color-coded duplex sonography of the parotid gland in Sjögren's syndrome].

27 patients with confirmed Sjögren's syndrome were examined prospectively by means of colour coded duplex sonography and pulsed Doppler sonography in order to determine blood flow in the parotid gland in this condition. Organ perfusion was divided semi-quantitatively into 4 groups: grade 0 (no intraglandular perfusion recognised) to grade 3 (numerous intra-glandular flow signals). Low perfusion values (grade 0 or grade 1) were found in normals and this was also observed in 13 patients (48%). 6 patients (22%) showed moderate increase (grade 2), and 8 patients (30%) showed gross increase (grade 3) in glandular perfusion. The increase in perfusion correlated with the severity of the sono-morphological glandular changes, such as reduced echogenicity, increased size and heterogeneous structure. Increased perfusion was associated with intra-glandular flow velocity as measured by Doppler sonography; maximal systolic flow velocity was significantly higher in patients with markedly increased perfusion than in normals.

Adult↗
PubMed1994

[Imaging in parotid tumors: US versus MRT].

27 patients, clinically suspected of having parotid tumours, were examined prospectively by sonography (high frequency linear array) and MRI (1.5 T, T1- and T2-weighted SE sequences before, and T1-weighted SE sequences after contrast). In 23 patients, 25 intraglandular tumours were demonstrated (two were multicentric); they consisted of 6 malignant parotid tumours, 11 pleomorphic adenomas, 7 cystadenolymphomas and one oncocytic adenoma. 4 patients had extraglandular tumours. All tumours were demonstrated by either method, but two extraglandular tumours were incorrectly diagnosed by sonography as being intraglandular and 8 tumours (28%) were not completely delineated by sonography. MRI localised the tumours correctly in all cases and demonstrated all lesions accurately, independent of their position or size. In summary, sonography appears suitable as the primary imaging method in the investigation of parotid tumours but in case of large, parapharyngeal or malignant tumours, MRI is clearly superior to sonography.

Adolescent↗
PubMed1994

The microvasculature of the larynx: a scanning electron microscopic study.

In ten adult guinea pigs, the microvascular architecture of the larynx was evaluated using microvascular corrosion casts and scanning electron microscopy. The vocal cords were provided with a subepithelial capillary network. The capillaries, freely anastomosing with each other, were supplied and drained via strongly undulating arteries and veins. The undulation of the latter vessels may explain their adaptability to volume changes of the larynx during phonation. The vasculature of the internal perichondrium of the thyroid cartilage was interrupted at the anterior commissure where an avascular zone was present at the origin of the vocal cords. This avascular area is common to both guinea pigs and humans and may explain the particular mode of tumor spreading, i.e., that the tumors remain unilateral for a long time. The rich vascular supply of the laryngeal mucosa prevents the organ from ischemic complications during surgical procedures. Our results show that the guinea pig may serve as a model for study of laryngeal disorders.

Animals↗
PubMed1994

[Non-neoplastic changes in the salivary glands].

Non-neoplastic disorders of the salivary glands are divided into the following groups: malformations, salivary gland cysts, sialadenosis, sialolithiasis, sialadenitis, HIV-associated salivary gland disease, oncocytosis and necrotizing sialometaplasia (salivary gland infarction). Clinically, an etiological classification of sialadenitis is mandatory. Sialadenosis is distinguishable from sialadenitis by its clinical, radiological, and morphological characteristics. Non-neoplastic cysts make up about 6% of diseases of the salivary glands. Mucoceles represent the majority of these cysts (75%). HIV-associated salivary gland disease includes lymphoepithelial lesions and cysts involving the salivary gland tissue and/or intraglandular lymph nodes, and Sjögren's syndrome-like conditions, diffuse interstitial lymphocytosis syndrome, and other reported lesions of the major salivary glands. The diagnosis, differential diagnosis, symptoms and treatment of different non-neoplastic salivary gland disorders are discussed.

Diagnosis, Differential↗
PubMed1994

[Salivary gland tumors. Clinical aspects and therapy].

Salivary gland tumors are rare. One-fifth are malignant. The parotid is the gland most often affected, particularly in adenomas. Adenomas and carcinomas are tumors that occur in adulthood; angiomas are the tumors that occur most frequently in childhood. Other than their localization, salivary gland tumors have few specific signs. In the clinical examination the locoregional and functional presentation is evaluated. Imaging studies refine or correct the clinical diagnosis, primarily by visualizing the deeper planes. Morphological diagnosis in benign lesions depends on resection results; in malignant lesions additional intraoperative frozen section is needed, and in questionable cases incisional biopsy. Fine-needle aspiration cytology may provide valuable knowledge when planning therapy. Limited parotid tumors are resected by lateral or subtotal parotidectomy. Carcinomas are resected as needed, with neck dissection added in case of lymph-node involvement. Small adenoid cystic carcinomas can be treated curatively by very wide resection. Aggressive and extensive tumors are irradiated postoperatively. Malignancies not operated upon are irradiated primarily. Facial nerve paralysis can be rehabilitated by different nerve repair or static surgical techniques.

Adult↗
PubMed1993

The cochlear glomeruli in the modiolus of the guinea pig.

The cochlear glomeruli were studied in guinea pigs using scanning electron microscopy of vascular corrosion casts and transmission electron microscopy of tissue sections. Two types of coiled vessels forming the cochlear glomeruli were found in the bony wall of the modiolus. First, upper glomeruli were seen situated in the bony wall next to the scala vestibuli; second, lower glomeruli were located in the osseous spiral lamina just above the spiral ganglion. Upper glomeruli gave rise to radiating arterioles which supplied capillaries of the stria the spiral lamina and limbus. Unlike the main supplying arteries, smooth muscle cells were not present in the walls of the arterioles forming the glomeruli and a peculiar layer of lamellar pericytes was found. The arterioles were strikingly longer than their parent vessels and no autonomic nerves were found in close spatial relationship. Hence, these findings indicate that the cochlear glomeruli serve as efficient devices for reducing cochlear blood pressure.

Animals↗
PubMed1993

[The sonography of laryngeal cysts].

To evaluate the sonographic appearance of laryngeal cysts, ultrasound examinations of 7 patients were evaluated retrospectively. The ultrasound studies were correlated with endoscopic findings. In two cases, the diagnosis was confirmed histologically, and in 4 patients, a CT examination was additionally performed. The endolaryngeal space could be well seen if the thyroid cartilage was not calcified (n = 6), whereas in one patient, the endolaryngeal part of the cyst could not be seen because of complete calcification of the thyroid cartilage. The laryngeal cysts presented as unechoic (n = 4) or hypoechoic (n = 3) masses, which demonstrated smooth margins in all cases and ranged in size from 6 to 38 mm. In three cases, the cyst was located in the endolaryngeal space, and in 4 cases, it extended cranial of the thyroid cartilage into the pre-epiglottic space. All cysts were closely related to the inner surface of the thyroid cartilage, from which they were delineated by a thin hyperechoic band in all cases.

Adult↗
PubMed1993

Fine structure of the tendon of the human stapedius muscle: comparison of normals and clinically otosclerotic patients.

The tendon of the human stapedius muscle was studied in normal post mortem material and in clinical otosclerotic patients, using light and electron microscopy. Cross section profiles of collagen fibrils were measured in various regions of the tendon and the amount of elastin was estimated. The normal stapedius tendon consisted of three concentrically arranged portions: A cylindrical central part, a tube-like mid-portion, and a cortical layer. The central part was made up of collagen fibrils with only a few elastic fibers, the mid-portion contained collagen fibrils together with significantly more elastic material, while the cortical layer, again, showed a smaller amount of elastic fibers. Mean diameters of collagen fibrils in the central part of the tendon were 65.12 +/- 11.89 nm, in the intermediate layer 41.00 +/- 9.63 nm, and in the cortical layer 70.28 +/- 19.58 nm. Stapedius tendons from clinically otosclerotic patients, though showing the same construction, were characterized by significantly altered collagen fibrillar diameters (Mann-Whitney U-test). In the central part, mean diameters were reduced to 61.05 +/- 14.70 nm, in the mid-portion increased to 50.90 +/- 10.08 nm, and in the cortical layer reduced to 61.09 +/- 8.49 nm. The changes of collagen cross section profiles estimated for the entire tendon were significant as well: 59.68 +/- 18.74 nm in controls versus 57.82 +/- 12.53 nm in otosclerotic patients. Elastin content in the mid-portion of control stapedius tendons increased with age (13% at 35 years of age to 35% at 70 years of age).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Prostaglandin synthesis by the lateral cochlear wall under streptomycin influence.

The synthesis of 4 prostaglandins (PGs), PGD2, PGE2, PGF2 alpha and PGI2, detected as 6keto PGF1 alpha in the guinea pig lateral cochlear wall (LW) was investigated under streptomycin treatment. Animals underwent daily injections of the antibiotic at dosages of 20, 100 and 200 mg/kg body weight. Prostaglandins were detected 1, 5 and 10 days after drug administration using radioimmunoassay. Under aminoglycoside administration a general reduction of PG-synthesis was evident, which was highest for PGI2. Already after 5 days of treatment the PGI2-synthesis was decreased down to 50% under the lowest drug dosage. The highest antibiotic dosage induced an abrupt decline of PGI2 synthesis, down to 26%, in animals with the longest duration of treatment. The significant synthesis reduction of PGI2 was followed by PGE2. The reduction of PG-synthesis seems to be influenced rather by duration than dosage of drug administration. The decreased synthesis of PGs under streptomycin treatment is interpreted as an inhibition of cell membrane phospholipids, the phosphoinositides. This assumption becomes plausible since the phospholipids represent endogenous precursors of the PG-synthesis.

Animals↗
PubMed1991

The vascularization of the digestive tract studied by scanning electron microscopy with special emphasis on the teeth, esophagus, stomach, small and large intestine, pancreas, and liver.

The periodontal vessels in adult rats show a ladderlike pattern; in guinea pigs molars, by contrast, they present a honey-comb pattern. The vascular architecture in human teeth seems to be similar to that of rabbits. In guinea pigs, rats, rabbits and humans esophagus circumferential vessels give off perforating vessels. In human esophagus the number and diameter of the vessels in the submucous venous plexus decrease from proximal to distal. In the stomach the subepithelial capillary network shows a honey-comb pattern reflecting the arrangement of the gastric pits. A local portal system between the gastric glands and the surface mucosal cells for the transport of HCO3- ions has been suggested. In the small intestine of humans and rabbits the existence of a dual blood supply of the villus has meanwhile been established. It consists of pericryptal capillaries for the lower portion of the villus (tuft pattern) and a direct arterial supply up to the villus tip (fountain pattern). The colonic microvasculature closely resembles that of the stomach. In the pancreas the insulo-acinar portal system is physiologically significant in that it connects the venules draining the islets with the acini. Venous sphincters in the vascular system of the exocrine pancreas of the rat are of particular functional importance. The hepatic sinusoids are supplied both by the hepatic artery and the branches of the portal vein. The peribiliary plexus is supplied by the afferent vessels of the hepatic artery, the efferent vessels drain the plexus either into the sinusoids or into the lobular vein.

Animals↗
PubMed1991

Sphincters in the rat pulmonary veins. Comparison of scanning electron and transmission electron microscopic studies.

The microvasculature of the rat lung was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of vascular corrosion casts and tissue sections. Particular emphasis was placed on postcapillary venules, pulmonary venules and small pulmonary veins (small interlobular veins). Casts of lung capillaries appeared inconspicuous with smooth surface. On the casts of pulmonary venules and small pulmonary veins, by contrast, series of narrow annular constrictions, present at regular distances of 20-25 microns, were seen. These constrictions may be drastic, narrowing down the caliber of the vessel up to 50%. In the constrictions the marks of circularly running tubular structures were seen and were interpreted as being caused by circular bands of smooth muscle cells. Tissue sections of the corresponding vascular wall showed the presence of single or grouped smooth muscle cells which regularly formed myoendothelial junctions. These smooth muscle cells are interpreted as sphincters, responsible for the constrictions seen on cast preparations. Axon terminals were not found in spatial relationship to these sphincters. It is suggested that the described venous sphincters are governed by blood-borne and/or endothelium-derived substances and may significantly influence the blood flow.

Animals↗
PubMed1991

Microvascularization of the pleura in rats and guinea pigs.

The microvascularization of the visceral and parietal pleura was studied in rats and guinea pigs using vascular corrosion casts and scanning electron microscopy. The visceral pleura was shown to be devoid of a vascular bed of its own. The capillary meshwork observed on the surface of the lung belongs to the pulmonary parenchyma. The parietal pleura, by contrast, possesses its own capillary network with an appropriate arterial supply and a venous drainage. The parietal pleural capillaries cover the costal regions completely, whereas the intercostal spaces are only provided by interspersed small patches of capillaries. That the feeding arteries of the parietal pleura are connected to the systemic circulatory system, supports the well-known fact that the parietal pleura is the main site for production of pleural fluid.

Animals↗
PubMed1990

Mandibular and molar vascularization in guinea pigs. Scanning electron microscopic study of corrosion casts.

The vascularization of the mandible, molar teeth, and periodontal ligament of adult male and female albino guinea pigs (Cavia porcellus) was studied by scanning electron microscopy of vascular corrosion casts. Main routes of mandibular blood supply and drainage are shown, and the intrinsic vascular patterns of the mandible, the molars, and the periodontal ligament are described. Results are compared to findings in man and in other mammals.

Animals↗
PubMed1990

Arcade-like anastomoses between the posterior intercostal arteries in man.

The intercostal arteries of 12 nonpreserved human bodies were investigated: in 8 specimens they were injected with Latex for anatomical preparation, 4 specimens were radiographed after injection of Angiographin. Arcade-shaped anastomoses were consistently found to be present between neighboring intercostal arteries IV-VIII; frequently, inconstant arcade-like communications were seen as far down as the 11th intercostal artery. The superior and inferior ends of each arcade were equidistant from the aorta as were the right and left arcades. Communications on the right side were stronger than those on the left.

Aged↗