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Biomedical subjects

G Berger

Publications and source records attributed to G Berger.

At least 127 records · Page 7Linked to original sources
PubMed1994

Non-explosive blast injury of the ear.

Non-explosive blast injury of the ear refers to the otological trauma caused by a blow to the ear that seals the external auditory meatus. It results in a sudden increase of air pressure within the ear canal that strikes the tympanic membrane. The present study portrays the various aspects of middle and inner ear damage in 91 patients resulting from an assault we entitled a 'non-explosive blast injury' to the ear. Sixty cases were caused by a slap or a fist, 13 patients suffered sport accidents, mostly in ball games, and 18 patients were injured during swimming and water sports activities. The common symptoms were hearing loss, earache, tinnitus, vertigo and otorrhoea. All 91 patients presented with acute perforations of their eardrums. The mean conductive hearing loss was 11.2 dB. A high tone sensorineural hearing loss was detected in only 20 per cent of the patients. A spontaneous closure of the perforation with a conservative management approach was observed in 94.8 per cent of the patients. Healing of the perforation was always associated with closure of the air-bone gap, while the results of the sensorineural hearing loss recovery were less favourable.

Adolescent↗
PubMed1994

Ultrastructural localization of the small GTP-binding protein Rap1 in human platelets and megakaryocytes.

Several functions have been proposed for Rap1B in human platelets, including the regulation of phospholipase (PL) C gamma and Ca2+ ATPase. However, its localization is largely unknown. In the present study we have investigated the subcellular distribution of Rap1 by immunocytochemical techniques using affinity purified polyclonal antibodies raised against residues 121-137 common to the 95% homologous Rap1A and Rap1B proteins. By immunofluorescence, a positive labelling was obtained on intact resting platelets and was abolished after adsorption of the antibodies with the control peptide. Immunoelectron microscopy was then used to further define the subcellular localization of Rap1B in platelets and megakaryocytes (MK). In resting cells, immunolabelling for Rap1B was associated with the plasma membrane, mostly at its inner face, and lined the membrane of the open canalicular system (OCS). Some labelling was also found outlining the alpha-granules, identified as such by a double labelling with an anti-GPIIb-IIIa. On thrombasthenic platelets the same localization was observed. When platelets were stimulated by thrombin, immunolabelling for Rap1B was redistributed to the zones of fusion of the granules with the OCS, and to the plasma membrane with a higher concentration on pseudopods. Human MK expressed Rap1 and the staining revealed the association of the protein with the demarcation membranes and alpha-granules. This study presents a first approach to the localization of a small GTP binding-protein Rap1B in whole platelets and MK, and shows its association with both the plasma and OCS membranes, as well as with the alpha-granule membranes.

Adenosine Diphosphate↗
PubMed1994

Possible role of adenoid mast cells in the pathogenesis of secretory otitis media.

The distribution of mast cells in the adenoidectomy specimens of 76 children with enlarged adenoids was studied. Forty of the patients had secretory otitis media; the remaining 36 had normally aerated middle ears. The mast cells were identified on the basis of the metachromatic staining of their cytoplasmic granules with toluidine blue. Patients with secretory otitis media had a twofold increase of their mast cell population compared to those without middle ear disease. Statistical analysis confirmed that the difference between the two groups is significant (p = .0001). The results of the study are consistent with the previous finding of increased histamine concentration in adenoids of children with secretory otitis media and lend support to the adenoid mediator release hypothesis, whereby the adenoid mast cells degranulate and release histamine and other inflammatory mediators that induce eustachian tube insufficiency and otitis media with effusion.

Adenoidectomy↗
PubMed1994

Ultrasound attenuation imaging in the os calcis: an improved method.

A complete assessment of the broadband ultrasonic attenuation (BUA) distribution within the os calcis was made using an ultrasonic mechanical scanning device with focused transducers. Measurements were performed on 12 os calces removed from fresh female cadavers. We present the first images of BUA of the os calcis. Reasonably high quality images were obtained compared to computed tomography. The resolution provided by the focused transducers is approximately 4 or 5 mm in the focal zone. Compared to dual energy X-ray absorptiometry (DEXA) or quantitative computed tomography, ultrasound imaging of the os calcis offers the possibility of controlling the placement, size and shape of the region of interest and to use multiple measurement sites. DEXA was used systematically to measure the bone mineral density (BMD) of the os calces. A highly significant correlation between BMD and BUA was found (r = 0.97 p < 0.001).

Absorptiometry, Photon↗
PubMed1994

Bone characterization with ultrasound: state of the art and new proposal.

Ultrasound transmission measurement through the os calcis is an emerging technique and a promising clinical tool for early assessment of osteoporosis. In this paper we first present a short discussion on the physical meaning of ultrasound velocity and attenuation, the methods of measurements and the potential contribution of ultrasound compared to photon absorptiometry. After analysing the various results in vivo published up to now we shall present some new perspectives of ultrasonic bone characterization: broadband ultrasonic attenuation imaging (BUAI) and pulse-echo measurement.

Absorptiometry, Photon↗
PubMed1994

Deciphering the molecular genetics of congenital heart disease.

Congenital heart diseases are starting to benefit from the major advances provided by the advent of molecular biology methods. It is now possible to identify genes which are responsible for congenital heart diseases. The gene responsible for supravalvular aortic stenosis--an autosomal dominant trait--was cloned last year. It is the elastin gene. DiGeorge and Shprintzen syndromes, conotruncal anomaly face and some cardiac malformations have a common cause: a deletion of the 22q11 region resulting in a monosomy. Although the region of deletion is large, it is possible that monosomy of only one gene results in these conditions. Studies are underway to evaluate the impact of this new genetic factor on the incidence of congenital heart malformations. Studies on familial bundle branch block, and lateralization defect with midline anomalies are soon going to show a chromosomal region with the gene defect. Discovering the genes and their protein products which are implied in the cardiac morphogenesis will definitively change our understanding of these cardiac malformations.

Abnormalities, Multiple↗
PubMed1993

Ultrastructural demonstration of CD36 in the alpha-granule membrane of human platelets and megakaryocytes.

CD36 (glycoprotein [GP] IV) is a membrane GP of 88 kD found on monocytes, endothelial cells, and platelets. It may serve as a receptor for collagen and is also able to bind thrombospondin (TSP), because a monoclonal antibody to CD36 inhibits TSP binding to thrombin-stimulated platelets. In the following study, we investigated the subcellular distribution of CD36 within normal resting platelets, thrombin-stimulated platelets, and in cultured megakaryocytes (MK) by an immunogold staining technique and electron microscopy. We used an affinity-purified monospecific polyclonal antibody showing a single major band of precipitation at 88 kD via immunoblot analysis. In normal platelets, ultrastructural observation detected immunolabeling for CD36, homogeneously distributed along the platelet plasma membrane and in the luminal side of the open canalicular system (OCS). Moreover, some labeling was found around the alpha-granules along the inner face of their limiting membrane. An average of 70% of granules were labeled. The granule-associated pool of CD36 was estimated at approximately 25% of the total cell content. To exclude the possibility of a cross-reaction with GPIIb-IIIa, platelets from a patient with type I Glanzmann's thrombasthenia (which completely lack GPIIb-IIIa) were studied and showed a similar subcellular distribution of CD36, including alpha-granule membrane labeling. In activated platelets, CD36 was shown to be redistributed to the OCS and pseudopods of the plasma membrane. Platelets from a patient with the Gray platelet syndrome expressed CD36 on their plasma membrane, and some immunolabeling was also found within small abnormal alpha-granules. In cultured MK, CD36 immunolabeling was detected in the Golgi saccules, associated vesicles, immature alpha-granules, and demarcation membranes. In conclusion, this study shows the existence of a significant intragranular pool of CD36 in platelets that may play a critical role in the surface expression of alpha-granule TSP during platelet activation.

Adult↗
PubMed1993

Eustachian tube submucosal glands in normal and pathological temporal bones.

Histological data concerning the structure and the topographical distribution of the eustachian tube submucosal glands is presented in 94 serially-sectioned temporal bones with and without otitis media. The vast majority of the tubal glands are located adjacent to the nasopharynx in the pharyngeal and midportion regions. Mixed glands which contain equal amounts of mucoid and serous elements are found in all age groups, in most specimens, either with or without otitis media. Furthermore, the glandular tissue, along these two medial regions of the tube, does not disclose significant quantitative differences between normal and inflamed specimens. Temporal bones without otitis media harbour few glands in the lateral four regions of the tube, while those with otitis media show a moderate increase of gland formation which is more noticeable in the pretympanum than in the regions around the isthmus (pre-isthmus, isthmus and post-isthmus regions). It is apparent that chronic inflammatory conditions like simple chronic otitis media and secretory otitis media are more often accompanied by gland formation, along the lateral four regions of the tube than acute otitis media.

Acute Disease↗
PubMed1993

Assessment of echography as a monitoring technique for cryosurgery.

One of the principal difficulties encountered in cryosurgery is to know the extent and depth of the frozen tissue boundary during the freezing process and the extent of the cryonecrosis in the postfreezing period. These problems have to be solved for cryosurgery to be a controlled therapeutic method and to avoid injuries to tissues adjacent to the tumor. The aim of this study was to evaluate echographic possibilities in monitoring the freezing process during cryotherapy in dermatology. In this paper, we describe the first experimental results of ultrasound monitoring of the freezing process with a 15 MHz transducer on pig skin in vitro. We show that it is possible to easily detect the depth boundary of the frozen region. Conventional linear filtering of the echographic signals can be very useful for SNR enhancement in the detection of a target signal drowned in speckle noise. Measurement of the kinetics of the freeze-thaw cycle (thickness of the frozen region versus time) is also measurable, which is of major importance as it allows the exact adjustment of the freezing time as a function the extent of tumor depth. Cryotherapy monitoring by ultrasound, added to the new diagnostic possibilities of high frequency ultrasound transducers, makes it an interesting controlled therapeutic method in such clinical fields as dermatology.

Animals↗
PubMed1993

Peritonsillar abscess as a cause of transient velopharyngeal insufficiency.

"Hot potato voice" is a characteristic sign of peritonsillar abscess and peritonsillitis. Our findings show that the hot potato voice is the result of an underlying transient velopharyngeal insufficiency combined with muffled oral resonance. The hot potato voice should be distinguished from the muffled oral voice which can be occasionally encountered in cases of severe tonsillitis. The velopharyngeal insufficiency is the result of transient dysfunction of the palatal muscles on the affected side. Transient negative middle-ear pressure indicating eustachian tube dysfunction was found in few of the patients in whom concomitant sinusitis was also present. The clinical, nasendoscopic, and radiologic findings are analyzed and discussed. We believe that this phenomenon is valuable as a research tool for the investigation of the anatomy and physiology of the velopharyngeal valve.

Acoustic Impedance Tests↗
PubMed1993

[Neurovascular ultrasound diagnosis].

Continuous-wave Doppler sonography of the carotid and vertebral arteries is a screening method. A subtle examination of these arteries is possible by duplex scanning and color-coded duplex scanning. For the examination of the intracranial vascular system, transcranial Doppler sonography and transcranial color-coded real-time sonography with various function tests are available. Advantages, accuracy and pitfalls are discussed.

Blood Flow Velocity↗
PubMed1993

[Are there prognostic parameters for predicting the success of regional chemotherapy in nonresectable liver metastases of colorectal cancer?].

When compared with systemic therapy, hepatic arterial chemotherapy significantly increases the response rate for hepatic metastases from colorectal carcinomas. However, only 2 studies showed a significant prolongation of survival. In our study on 54 patients tumor related characteristics and the response to regional chemotherapy were correlated to the success of the treatment. In a linear discriminant analysis the response to regional chemotherapy was the main prognostic factor for the 1-year survival, rate, followed by positive lymph nodes in the Lig. hepatoduodenale. The other pretherapeutic factors such as liver involvement and CEA rate were of less importance.

Adult↗
PubMed1993

[Chemoembolization of liver tumors (VX-2) using lyophilized Spherex].

Chemoembolisation is a new promising approach. Until now no standardized procedures exist for the production of the embolisate-cytostatics mixture. A main technical problem when doing chemoembolisation is the proof of the complete peripheral vascular occlusion. By using lyophilized Spherex and cytostatics, diluted in x-ray contrast media, frozen pictures can be obtained and the complete proof of the embolisation is possible. Therefore the conventional x-ray examination can be used to monitor the embolisation treatment instead of the much more sophisticated DSA technique.

Animals↗
PubMed1992

Liver tumors: follow-up with P-31 MR spectroscopy after local chemotherapy and chemoembolization.

The authors examined and quantified the changes observed in the phosphorus-31 magnetic resonance (MR) spectra of liver tumors after chemotherapy and chemoembolization to investigate the suitability of P-31 MR spectroscopy for follow-up. A 1.5-T unit was used before and at specific times during therapy to obtain spectra of liver tumors in 10 patients with liver metastases from colorectal carcinoma and two patients with hepatocellular carcinoma. A marked increase in inorganic phosphate and a decrease in the alpha- and beta-nucleotide phosphate portions of the spectra were observed during the first few hours after local chemotherapy or chemoembolization. Later, the phosphomonoester signals increased markedly and the phosphodiester signals decreased slightly. The effects of successful chemoembolization or local chemotherapy become apparent in the P-31 MR spectrum during the first few hours after the start of therapy. The results demonstrate that P-31 MR spectroscopy is a suitable method for follow-up. However, long-term studies are needed to determine whether it also yields prognostic information.

Carcinoma, Hepatocellular↗
PubMed1992

[Oncocytic presentation of a primary epithelioid leiomyosarcoma of the liver].

We report an epithelioid leiomyosarcoma of the liver with oncocytic differentiation. Initially misdiagnosed as an oncocytic endocrine tumor, analysis of the whole liver after transplantation permits rectification of the diagnosis. This observation outlines the fact that oncocytic differentiation is not restricted to epithelial cells but can also be encountered in cells of mesenchymal lineage.

Humans↗
PubMed1991

[Therapeutic protocols in the treatment of liver metastases].

The liver is the main site for metastatic spread from many cancer, particularly those of the colorectum. Surgical treatment of liver metastases is nowadays a safety therapeutical approach, which has been improved by the development of modern imaging procedures, clear indications and standardized surgical techniques. In carefully selected patients the 5-year survival ranges between 30-40%. Unfortunately only 20% of the patients with liver metastases are candidates for this potentially curative therapy. Palliative modalities remain for the majority of patients with unresectable metastases limited to the liver. Although various types of intrahepatic arterial chemotherapy, sometimes in combination with whole liver irradiation or embolization shows a higher response rate than systemic chemotherapy no significant impact on survival time has been proven. One of the main unsolved problem is the extrahepatic spread. For getting better results--median survival of responders ranges between 18 to 24 months versus 8 months of non-responders--a more exact selection is needed.

Antineoplastic Agents↗
PubMed1990

Induction by different thioredoxins of ATPase activity in coupling factor 1 from spinach chloroplasts.

ATPase activity of the coupling factor 1, CF1, isolated from spinach chloroplasts, was enhanced by reduction with dithiothreitol. Reduced thioredoxins from spinach chloroplasts, Escherichia coli and human lymphocytes replaced dithiothreitol as reductant and activator of the ATPase. CF1 must be in an oxidized activated state to be further activated by reduced thioredoxin. This state was obtained either by heating CF1 or removing the inhibitory intrinsic epsilon subunit from CF1. Efficiency and primary structure of the different thioredoxins were compared. The progressive addition of KCl during ATPase activation by reduced thioredoxin increases then decreases this process. We proposed that three basic amino acids corresponding to arginine 73 and lysines 82 and 96 in Escherichia coli thioredoxin play an important role in the anchorage of the thioredoxin to the negatively charged surface of the CF1 and are involved in the dual effect of KCl. The variations in the screening effect of the negative charges of the CF1 surface by K+ ions can indeed explain the changes in the anchorage of these 3 basic amino acids with concomitant variation in ATPase activity. Human thioredoxin must be 10 times more concentrated than Escherichia coli or spinach chloroplast thioredoxin to exhibit the same activation effect on the ATPase. This fact was related to the properties of a sequence equivalent to the part from amino acid 59 to 72 in Escherichia coli thioredoxin. This part which joins the two lobes of the thioredoxin is more hydrophilic and more negatively charged in human thioredoxin than in Escherichia coli or spinach chloroplast thioredoxin. Although ATPase activation was obtained at a very low concentration of the reduced spinach chloroplast thioredoxin, the thioredoxin formed only a loose complex with CF1.

Amino Acid Sequence↗