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Biomedical subjects

H Iro

Publications and source records attributed to H Iro.

At least 109 records · Page 6Linked to original sources
PubMed1996

In vitro effects of high-energy pulsed ultrasound on human squamous cell carcinoma cells.

Human squamous cell carcinoma cells cloned from the hypopharynx (FaDu) and oral cavity (SCC-4) were exposed to high-energy pulsed ultrasound (HEPUS) in vitro to evaluate the effects of various physical parameters on cell viability. Such included the number of pulses, voltage applied, pulse repetition rate and cell density. The experimental piezoelectric ultrasound transducer used in the experiments generated pulses with a high negative pressure amplitude. By varying the repetition frequency from 0.6 to 8 Hz, cell viability was found to be least when pulse repetition was approximately 1 Hz. An increase in transducer voltage resulted in a linear decrease in cell viability. The cell survival rate dropped exponentially as a function of the number of pulses applied, reaching 4.2% after 2000 pulses. The cell survival rate exhibited no significant dependence on cell density when cells ranged from 1 to 3.5 x 10(6) cells ml-1. Data obtained with trypan blue dye exclusion were confirmed by measurements of intracellular lactate dehydrogenase released into an extracellular fluid supernatant. By applying HEPUS to tumor cells, almost complete destruction of the cells could be achieved in vitro. The degree of cell destruction achieved depended significantly on the number of pulses administered, the pulse repetition rate and the transducer voltage applied.

Carcinoma, Squamous Cell↗
PubMed1996

[Color Doppler ultrasound studies of benign and malignant lymph nodes].

Color-coded duplex sonography is being increasingly used in the head and neck as another method for diagnosis of such disorders as stenosis of arteries or veins or hemangiomas. A possible additional advantage of testing is the ability to differentiate benign from malignant tumors. Since the underlying cause of a suspicious lesion is most important for treatment strategies, we investigated histologically-proven benign and malignant cervical lymph nodes for determining the value of color-coded duplex sonography. In the present study, 135 patients (45 women and 90 men; ages 30-63 years) with palpable cervical lymph nodes were examined with both ultrasound and color-coded duplex sonography. Afterwards, lymph nodes were removed by open biopsies or neck dissections. The histological results were then compared to perfusion velocities and pulsation indices from the color-coded duplex sonography. However, no significant differences were found between the benign and malignant nodes. When comparing perfusion and color, each group was seen to be non-homogeneous and no typical distribution of vascularization was demonstrable. Findings showed that color-coded duplex sonography is currently not an accurate indicator of lymph node pathology.

Adult↗
PubMed1996

Biophysical effects of high-energy pulsed ultrasound on human cells.

Human benign and malignant cells of different human origin (pancreas, liver, kidney, pharynx, tongue, lip) were exposed to high-energy pulsed ultrasound (HEPUS) in vitro to evaluate the effects of various physical parameters and sonication conditions on cell viability. This included the number of pulses, focal pressure, pulse repetition rate, pulse shape, cell suspension volume, water level of the basin and cell density. Cell viability was found to depend significantly on the number of pulses (exponential), the focal pressure (linear) and the pulse repetition rate (minimum at 1 Hz). Other parameters showed no marked influence. Furthermore, electron microscopy revealed intracellular damage, and proliferation rates of cells surviving sonication were normal after HEPUS exposure. The experimental piezoelectric ultrasound transducer used in the experiments generated oscillating bipolar pulses with high negative pressure amplitudes. Measurements were made of the pulse shape and ultrasonic field of the experimental device and of a conventional lithotripter for comparison.

Biopsy↗
PubMed1996

[Current status of minimally invasive treatment methods in sialolithiasis].

Newly available minimally invasive methods have changed established treatment of human sialolithiasis during the past several years. After basic in vitro and in vivo investigations, two systems of shockwave treatment proved to be useful for clinical application: extracorporeal shockwave lithotripsy (piezoelectric system) and intracorporeal laser lithotripsy (using a rhodamine-6G dye laser). Following our clinical experiences with these methods a differential scheme for managing sialolithiasis is recommended depending on localization of the calculi and their maximal diameters. Submandibular stones are best treated by extra-corporeal lithotripsy if the stone is located in intraglandular parts or in the gland hilum. Stones of the hilum can also be treated by laser lithotripsy. In the distal parts and near the duct orifice, papillotomy and stone extraction should be tried independent of the stone size. If the stone is located in the intraglandular parts of the duct system or in the hilum and its diameter is over 12 mm, submandibulectomy is necessary. Calculi of the parotid gland should only be treated by extracorporeal lithotripsy, regardless of size and location.

Endoscopes↗
PubMed1995

[Asbestos dust-induced laryngeal carcinoma--a new occupational disease? Current scientific knowledge and social health regulations].

According to the current regulations pertaining to occupational diseases lung cancer and mesothelioma can be compensated as asbestos-related malignomas under certain circumstances. For several years there has been controversial discussion as to whether laryngeal carcinomas can also be caused by occupational asbestos exposure and should therefore be added to the list of occupational diseases. Critical evaluation of the available scientific knowledge with the scope of currently applicable regulations does not warrant adding asbestos-related laryngeal carcinomas to the list of occupational diseases at present. Further investigations are urgently necessary and may possibly bring new insights.

Aged↗
PubMed1995

[Pneumatic intracorporeal lithotripsy of salivary calculi. In vitro and animal experiment studies].

BACKGROUND: The effort to use minimally invasive strategies in the treatment of human sialolithiasis in principle seems to allow the clinical application of pneumatic lithotripsy because of the small diameters of the probes involved. While this kind of therapy is already used successfully in urology, we investigated the method during in vitro and animal experiments. MATERIALS AND METHODS: The treatment of stones and tissue utilized the pneumatic lithotripter "Lithoclast". This system works with ballistic energy and is similar to a biologic "pneumatic hammer". Thirty salivary calculi were treated with pneumatic lithotripsy. Four submandibular salivary glands and their ducts were removed intraoperatively and were exposed to the pneumatic probes. Moreover, in two cases a salivary concretion was also implanted prior to pneumatic lithotripsy. In two rabbits the ducts of the parotid glands were ligated for 2 weeks. On the basis of the in vitro experiments, concretions were placed in two of the four salivary ducts. Following this, the pneumatic probes were inserted along the ducts and lithotripsy was completed. RESULTS: All of the 30 salivary calculi were reduced to sizes smaller than 1.5 mm in diameter. No macroscopic or microscopic damage was detectable while the probe was in a duct. However, in both cases with implanted calculi retropulsion of fragments occurred consequent perforation of the ducts. After application of ballistic pulses along the duct, small periductal hematoma without any perforation were detected macroscopically. Microscopically, only small bleeding was observed along the submucosa and partial loss of epithelium was found. In contrast, the pulse application to the implanted concretions lead to destruction of the calculi with perforation of the ducts as well as hemorrhage in the surrounding tissue. CONCLUSIONS: The method of pneumatic lithotripsy used in the present study resulted in sufficient destruction of salivary calculi. In vitro and in vivo lithotripsy of duct implanted calculi led to perforation of the salivary duct in all cases. Because of these results, the clinical use of this technique to treat human sialolithiasis appears to be not justified.

Animals↗
PubMed1995

[Color Doppler ultrasound studies of parotid tumors].

BACKGROUND: Color-coded duplex sonography is being increasingly used in the head and neck as another method of diagnosis of, for example, stenosis of arteries or veins or of hemangioma. Moreover, it is of greatest interest in having the ability to differentiate benign from malignant tumors. Since the underlying type of tumor is directly responsible for the (operative) treatment recommended we have investigated histologically proven benign and malignant parotid tumors. PATIENTS: Thirty-six patients (20 women, 16 men, ages 32-66 years) with parotid tumors of unknown histology were examined by means of ultrasound and color-coded duplex sonography. Afterwards, tumors were treated by complete parotidectomy. Histological results were compared postoperatively to the data from the color-coded duplex sonography. MATERIALS AND METHODS: Ultrasound B sonography. All patients were examined with a "Sonoline SI-450" (Siemens), using a 7.5 MHz transducer. Color-coded sonography. The color-coded duplex sonograph used was the Quantum 2000 (Siemens). All investigations were carried out with a 7.5 MHz transducer. Criteria of color-coded duplex sonography. Criteria of the investigation were the qualitative range of color distribution as an indication of vascularization and measurement of perfusion velocity--as far as possible--with mean pulsatility indices. The mean pulsatility index represented peripheral resistance and was proportional to it. All data were collected from three areas in the center of the tumor and tumor margins, respectively. Tumors selected were 17 histologically proven pleomorphic adenomas, 15 adenolymphomas and 4 adenoid cystic carcinomas. RESULTS. In comparing perfusion velocity and mean pulsatility indices, no significant difference was detected between pleomorphic adenomas and adenolymphomas. A loss of perfusion and color was seen in both tumor types, although it occurred more often in the adenolymphomas. These cystic areas in most cases had already been clearly detected with normal B-scan sonography. In two of the four malignancies there were no obvious differences to the benign tumors. In the other two cases of malignancy a pronounced vasularization was detected and, therefore, an extended distribution of color. This finding together with decreased perfusion velocity and low mean pulsatility indices indicated low peripheral resistance. CONCLUSIONS: At this point it is not possible routinely to utilize color-coded duplex sonography as an accurate indicator of underlying pathology of parotid neoplasms. A differentiation among different types of benign tumors is not possible using the technique, nor can malignancies be recognized definitively by this method.

Adenolymphoma↗
PubMed1995

[Severe oropharyngeal angioedema caused by ACE inhibitor. A case report].

Inhibitors of angiotensin converting enzyme (ACE) are suspected of inducing angioedemas in up to 0.2% of all patients. These angioedemas are mainly localized in the upper airways and therefore can cause severe airway obstruction and even death due to suffocation. We report the case of a 64-year-old man, who underwent emergency tracheotomy because of severe angioedema of the larynx, which was refractory to pharmacological treatment. We conclude that patients with ACE inhibitor-induced angioedemas should be observed by monitoring in an intensive care unit to ensure the possibility of early intubation, because conventional antiallergic-antiedematous therapy by histamine-receptor antagonists and corticosteroids is an insufficient, unreliable form of therapy in severe cases. Especially otolaryngologists should know about this uncommon potentially life-threatening side-effect of ACE inhibitors.

Angioedema↗
PubMed1995

[Imaging superficial skin tumors of the ENT area. High frequency ultrasound in comparison with computerized tomography and magnetic resonance tomography].

In order to improve the preoperative diagnosis of superficial skin tumors in the head and neck, 32 patients with 42 basal cell carcinomas, squamous cell carcinomas and malignant melanomas were investigated using different imaging techniques. All patients were examined preoperatively with high-frequency ultrasound (HFU), computed tomography (CT) and magnetic resonance imaging (MRI). New high-frequency ultrasonic scanners (15- and 20-MHz) having an axial resolution of 50-90 microns permit visualization of dermal and cartilaginous structures with an anatomical accuracy to a range of 15 mm in tissue. Exact measurement of the skin tumors and their relation to adjacent structures was feasible. Histologically different tumors could be discriminated by their echo-structure in 80% of the cases. CT and MRI provided additional information when the tumor extension perpendicular to the skin exceeded 15 mm. If tumor extension was less than 15 mm, CT and MRI were inferior to high-frequency ultrasound in the diagnosis of superficial skin tumors and did not provide any additional information. The experience reported has shown that high-frequency ultrasound is a valuable tool for preoperative evaluation of superficial skin tumors in terms of tumor extension and possible invasion of functionally and esthetically important adjacent structures. This knowledge can support preoperative planning of possible resections as well as reconstruction and may help to obtain an appropriate informed consent.

Adult↗
PubMed1995

[Pneumolabyrinth. Radiologic sign of perilymph fistula].

Post-traumatic cochleo-vestibular symptoms can be caused by peri-lymph fistulas, although these cannot be proven preoperatively in most cases by direct clinical examination. A rare case of a traumatic burst fracture of the promotory wall with a consequent perilymph fistula is presented. A preoperative computed tomographic finding of air in the basal turn of the cochlea and superior semicircular canal (pneumolabyrinth) is a reliable sign of perilymph fistula and justifies operative exploration for closure of the fistula. High-resolution computer tomographic imaging of the petrous bones in patients with post-traumatic cochleo-vestibular disturbances is mandatory.

Adult↗
PubMed1994

Multivariate analysis of prognostic parameters using interstitial thermoradiotherapy (IHT-IRT): tumor and treatment variables predict outcome.

PURPOSE: From January 1986 to October 1991, 90 patients with localized tumors were treated in a Phase I/II trial using low-dose 192Ir brachytherapy (IRT) plus interstitial 915 MHz microwave (MW) hyperthermia (IHT) and external beam radiotherapy (ERT). Tumors were classified as locally advanced primary (class 1: 27), recurrent (class 2: 40), metastatic (class 3: 10) and persistent (class 4: 13) lesions. The treatment sites included tumors of the head and neck (62), pelvis (26), and others (2). The mean cuboidal tumor volume was 63 cm3 (range: 8-288 cm3). Most recurrent and metastatic lesions (48) had received prior treatment including ERT. METHODS AND MATERIALS: The treatment protocol prescribed two heating sessions (each 60 min) at 41-44 degrees C before and after IRT. One hundred sixty-one IHT sessions were evaluated. Invasive thermal data were recorded at an average of 18 sites throughout the implant volume. Several thermal variables were analyzed (e.g., averaged parameters: Tmaxav, Tmean, Tminav; index parameters: T10, T50, T90). The study was evaluated with a minimum follow up (FU) of one year. Median follow-up was 19 months. RESULTS: At 3 months FU, a complete response (CR) was observed in 59 of 90 (66%) patients. At 12 months FU, local control (LC) was achieved in 54 of 84 (64%) evaluable patients. Ten patients developed a local and 14 a regional recurrence (REC) after achieving a CR and/or LC. At last FU, a total of 31 (34%) patients were still alive and 28 (31%) patients had relapse-free survival. For all 90 patients, the median overall survival was 20 months and the median relapse-free survival was 17 months. Overall and relapse-free survival was significantly longer for primary and persistent lesions as compared to recurrent and metastatic lesions (p = 0.002; p < 0.001). Totally 22 (24%) patients experienced acute or subacute side-effects (Grade 1: 12 patients; Grade 2: eight patients; Grade 3: two patients). CONCLUSION: Univariate logistic regression analysis revealed significant dependencies of CR, LC and REC upon tumor parameters as well as radiation and thermal parameters. The overall and relapse free survival was associated with tumor and radiation parameters. The multivariate analysis revealed two independent predictors of CR: tumor volume and minimum tumor temperature variables. We conclude, that IHT-IRT is a safe and effective treatment. The results provide important implications for planning HT-RT studies and for defining quality assurance (QA) criteria and thermal performance standards in HT studies.

Adolescent↗