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Biomedical subjects

E Laurikainen

Publications and source records attributed to E Laurikainen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Digital fluoroscopy before and after laser uvulopalatopharyngoplasty in obstructive sleep apnea. Importance of pharyngeal collapsibility and hyoid bone position.

PURPOSE: To study the changes in pharyngeal behavior after laser uvulopalatopharyhgoplasty (LUPPP). MATERIAL AND METHODS: The dynamic changes in the upper airway size were evaluated with digital fluoroscopy in 24 patients with obstructive sleep apnea (OSA) before and after LUPPP and in 16 normal controls, while they were awake and breathing normally. Cephalometric measurements were also made. The patients were classified into the categories of good and poor responders by means of a static-charge-sensitive bed. RESULTS: Following LUPPP, collapsibility at the velopharyngeal level was within the normal range m 15 of 17 good responders, but only in 2 of 7 poor responders (p = 0.0086). The minimum airway size at the same level showed a similar trend. In 3 of 7 poor responders the hyoid bone was positioned more caudally than in the good responders (p = 0.017). CONCLUSION: Digital fluoroscopy provides information on the change in upper airway behavior after LUPPP.

Adult↗
PubMed1997

Sudden deafness: a comparison of anticoagulant therapy and carbogen inhalation therapy.

Sudden deafness (SD) is a sudden or rapidly progressive, partial or complete, typically unilateral sensorineural hearing impairment that has no known specific etiologic factor. This study was designed to compare, in a group of 168 consecutive patients with SD, the effect of anticoagulant therapy and carbogen inhalation therapy. Special attention was paid to the shape of the audiogram relative to the clinical outcome and the treatment modality. We found that the configuration of the audiogram of SD patients is prognostic of the outcome, and that patients with a low-frequency-sloping hearing impairment have a better prognosis compared to the patients with a high-sloping loss. Anticoagulant treatment was most effective in low-sloping hearing losses, while carbogen inhalation may be more effective for patients with high-sloping hearing losses.

Administration, Inhalation↗
PubMed1997

The mechanism and site of action of lidocaine hydrochloride in guinea pig inner ear.

Lidocaine was applied to the round window (RW) in order to localize its site of action in the cochlea. Cochlear microphonic (CM), summating potential (SP), and compound action potential (CAP) input/output functions were measured to a 16 kHz tone burst to assess the functional changes of the cochlea. In separate experiments, the effect of lidocaine on the whole cell current of isolated outer hair cells (OHC) was studied. A dose of 2 microliters of 40 mM lidocaine in saline solution, when applied to the RW, caused a small change in all measured variables, indicating a passage of the drug through the RW membrane to sites of action. However, 160 mM of lidocaine further decreased CM, SP, and CAP by a total of 40% from the control. A partial recovery occurred for CM during the 30 min follow-up period. CAP and SP continued to decline. In isolated OHCs, lidocaine decreased the whole cell current in a dose-dependent fashion. The KD for lidocaine effect on OHCs was 7 mM. Our in vivo results indicate that lidocaine affects OHCs and reduces CM, causing a subsequent reduction in SP and CAP. The increased effect of lidocaine on CAP and SP, while CM is recovering, suggests an additional specific effect of lidocaine on the cochlear nerve and/or on inner hair cells. Considering that lidocaine alters OHC current (in isolated hair cells) and that lidocaine does not affect endocochlear potential [Laurikainen et al. Acta Otolaryngol (Stockh) 1991: 112: 800-9], the observed CM changes are most likely due to an in vivo effect on OHCs. Thus, the early effect of lidocaine on the cochlea appears to be due to a significant change in organ of Corti function, rather than to direct anesthesia of the cochlear nerve. Later, an independent effect of the drug may occur on neural tissues in the inner ear.

Animals↗
PubMed1997

Blood flow-independent accumulation of cisplatin in the guinea pig cochlea.

Considerable interindividual variability in the ototoxic effect of cisplatin has become the unpredictable dose-limiting factor in its use as curative as well as palliative therapy. The drug accumulates in highly vascular areas in the cochlea, causing dose-related hair cell loss. The purpose of this study was to assess blood flow-dependent aspects of cisplatin absorption in the cochlea in order to better understand factors that may influence cisplatin-induced ototoxicity. The effect of reduced cochlear blood flow on the ototoxic action of cisplatin was studied in guinea pigs. Before cisplatin administration the cochlear vasculature in each animal was unilaterally pre-constricted, by the application of 2% epinephrine to the round window. A 20-30% reduction in cochlear blood flow, assessed by laser Doppler flowmetry, was maintained before and after intravenous infusion of 0.1% cisplatin. Cisplatin infusion affected cochlear blood flow but not vessel conductivity. The cochlear blood flow decrease, maintained by local epinephrine application to the round window during cisplatin infusion, did not alter the cisplatin-induced hearing loss. In addition, the concentration of free cisplatin in scala tympani perilymph did not differ between epinephrine-treated and non-treated ears. Our results indicate that cisplatin transport into the cochlea is not an energy-dependent process in the lateral wall vasculature.

Animals↗
PubMed1997

Non-specific effect of beettahistine on cochlear electrophysiology in guinea pig.

Beettahistine hydrochloride (BH) is reported to be beneficial in the treatment of certain type of vestibulo-cochlear disorders. Experimentally is shown that BH inhibits vestibular firing rate and improves cochlear blood flow by dilatating the larger feeding vessels. Both these effects are weak, and hardly can explain the clinical benefits reported for the drug. We investigated the effect of BH on the organ of Corti electrophysiology in vivo. Two microliters of 1, 2, 5 and 10% saline solutions of BH was applied (in increasing order) to the round window (RW) membrane in an anesthetized guinea pig (n = 5). Summating potential (SP), action potential (AP), and cochlear microphonics (CM) were recorded at 16 kHz frequency using RW Ag wire electrode. The repeated applications of BH with increasing concentrations produced a dose-dependent threshold shift in CAP. The I/O function for 20, 30, 40, 50, 60, 70, and 80 dB at 16 kHz indicated that there was a saturation before complete blockade of the responsiveness in all measured parameters. SP and CM changes nearly followed CAP changes. The changes recover during 2 hours follow-up period. Our findings indicate that BH affects the organ of Corti electrophysiology. That the drug effect saturates before a complete blockade suggests non-specific effect of BH on the organ of Corti structures and cochlear nerve.

Animals↗
PubMed1997

Radiotherapy enhanced ototoxicity of cisplatin in children.

We reviewed and re-examined 31 children (6 months-14 years at the time of diagnosis), who had been treated for a neoplasm in Turku University Central Hospital between 1989 and 1994. The children were divided into 3 groups according to the site of the neoplasm and the type of therapy. Group I included 13 children, operated on for an intracranial tumor and received postoperative radio- and cisplatin-based chemotherapy. Group II included 14 children operated on for intracranial tumors and treated with radiotherapy, but not given chemotherapy. Group III included 4 children suffering from extracranial malignancies and they had received chemotherapy including cisplatin. The children in Group I had significantly worse hearing thresholds in the middle- and high-frequency range than children in Groups II and III. In a precise analysis of the different factors, no single dose of cisplatin, inner ear irradiation dose or totally to the central nervous system (CNS) received irradiation dose correlated to the detected hearing loss. However, multiple linear correlation analyses suggest a combined effect of radiotherapy plus cisplatin resulting in a high frequency hearing loss. This is in accordance with earlier random case reports, and supports the idea that radiotherapy should be considered cautiously in children treated with cisplatin for intracranial malignancies.

Adolescent↗
PubMed1997

The effect of laser-uvulopalatopharyngoplasty on the nasal and nasopharyngeal volume measured with acoustic rhinometry.

Nasal breathing is considered as an important factor in sleep apnea and snoring, and nasal obstruction can lead to an increased respiratory resistance and to inflammatory reactions in the nasal mucosa. Uvulopalatopharyngoplasty is an effective treatment for sleep apnea and snoring. Different operation techniques with minor variations have been introduced during the last few years. Uvulopalatopharyngoplasty with laser technique (LUPPP) has made it possible to perform the operation in local anesthesia. Acoustic rhinometry is a new method for the evaluation of the nasal cavities and the nasopharynx. We measured the volume of nasal cavities and nasopharynx of 29 patients using acoustic rhinometry before and 6 months after the LUPPP operation. There was a tendency to a better nasal patency in the turbinate area, but no change was found in the nasopharyngeal volume. Acoustic rhinometry is a useful tool for measuring the turbinate area, and this part of the nasal cavities seems to be influenced by the LUPPP operation, maybe due to a better ventilation or reduction of the inflammation of the nose. However, technical and methodological improvements are needed before reliable measurements are achieved from the nasopharynx area.

Acoustics↗
PubMed1996

Upper airway size and collapsibility in snorers: evaluation with digital fluoroscopy.

This study addressed the question of whether there are any differences in the size and collapsibility of the upper airway measured by digital fluoroscopy, between snorers and controls whilst they were awake and breathing normally; and whether there are any correlations between these measurements and other clinical data. The dynamic changes of the upper airway size were evaluated using digital fluoroscopy in 33 patients and 16 normal controls. The measurements were compared with findings in an overnight sleep study, including a static-charge-sensitive bed (SCSB) and oximeter recordings. The minimum anteroposterior dimension at the velopharyngeal level was smaller in patients with partial upper airway obstruction than in controls (p<0.005); patients with complete obstruction did not differ from the controls. The velopharyngeal airways were also more collapsible in patients with severe partial obstruction (p<0.01) than in controls. At the oropharyngeal and hypopharyngeal levels, the dimensions and the collapsibilities were similar in patients and controls. The velopharyngeal collapsibility correlated with body mass index (p<O.001), whereas the airway size did not. The velopharyngeal collapsibility was more pronounced in patients with frequent episodes of arterial oxyhaemoglobin desaturation during sleep. Velopharyngeal collapsibility associated with high body mass index was the important determinant of nocturnal breathing disturbances. Digital fluoroscopy displays the dynamic changes of the upper airways throughout the respiratory cycle.

Adult↗
PubMed1995

Hydrops-induced changes in cochlear blood flow.

Laser Doppler flowmetry was used to assess cochlear blood flow (CBF) in the hydropic ear in four experiments. 1) The increase in CBF elicited by local electrical stimulation of the cochlea in the hydropic ear was compared to that observed in normal controls. The magnitude of the evoked CBF change was reduced by approximately 30% in the hydropic ear compared to the normal ear. 2) The reduction in CBF evoked by direct electrical stimulation of the superior cervical ganglion was reduced by approximately one third in the hydropic ear compared to a normal ear. 3) Rhythmic (flux motion or vasomotion) variations in CBF, observed in association with lower blood pressure and thought to extend the autoregulatory range in an organ system, were reduced or eliminated in the hydropic ear. 4) The autoregulatory response to a decreased perfusion pressure, produced by decreased cardiac output, was clearly reduced relative to control in the hydropic ear. These findings represent the first report of significant CBF changes with hydrops. They are consistent with reports of increased sensitivity of the hydropic ear to trauma and stress and may be relevant considerations in the treatment of hydrops in humans.

Animals↗
PubMed1994

A critical look at the treatment of maxillary sinusitis with long-term draining tubes.

Long-term draining tubes (LTD) have become a common treatment in complicated and prolonged forms of maxillary sinus empyema. Since not all patients show good recovery with this treatment we used sinus-manometry, mathematical calculations, and scanning electron microscopy (SEM) to critically analyze 6 cases with a prolonged history of the disease. Five out of the 6 patients recovered quickly after removal of the LTDs, normally performed sinus punctures, and an appropriate antibacterial treatment. One patient underwent functional endoscopic sinus surgery. Two of the 6 patients had uncommon bacterial cultures (Pseudomonas mirabilis, Klebsiella oxytoga) in their sinus secreta. Two of the removed LTDs were examined with SEM. The porous polyethylene was shown to have absorbed bacterial plague which, besides narrowing the lumen, can cause recurrent infections. In 5 other patients, the draining pressure (DP) was 0.9 +/- 0.16(M +/- SD) kg/cm2, as measured during irrigation with a No. 2 Lichtwitz needle (1.8 mm, i.d). Mathematical calculation using the Hagen-Boisseouille equation indicated that with our LTDs (0.7 mm, i.d.) the DP needs to be 40 times greater than the DP when using an ordinary Lichtwitz needle to get equal flushing capacity. We recommend i) LTD treatment of maxillary sinus empyema be closely followed up ii) that, in prolonged cases, the LTDs should be removed and the sinuses repeatedly irrigated with an ordinary needle or antrostomy, and iii) that a more suitable tubing material and insertion system (to allow a larger radius of the tube) be developed.

Adolescent↗
PubMed1993

Substance P increases cochlear blood flow without changing cochlear electrophysiology in rats.

Carotid artery infusions of substance P yielded reductions in systemic blood pressure and elevations in cochlear blood flow (CoBF), measured via laser Doppler flowmeter, with no alterations in cochlear action potentials or cochlear microphonics in Wistar-Kyoto rats. Additionally, direct micro-infusions of substance P into the anterior inferior cerebellar artery, which contributes to the local vascular perfusion of the cochlea, yielded elevations in CoBF with no changes in systemic blood pressure. Pretreatment with a specific substance P receptor antagonist, ([D-Pro2,D-Trp7,9]SP) via the carotid artery or the anterior inferior cerebellar artery, diminished subsequent substance P-induced vascular responses. These results suggest that endogenous substance P, like other vasoactive peptides, may interact with a substance P-specific receptor population in the cochlea and may therefore participate in the ongoing regulation of CoBF. These findings also support the premise that vasodilatory hormones, along with vasoconstrictive agents, may be involved in the autoregulation of CoBF.

Action Potentials↗
PubMed1993

Effects of stellate ganglion stimulation on bilateral cochlear blood flow.

The effect of intraneural electrical stimulation of the stellate ganglion (SG) on bilateral cochlear blood flow (CBF) was investigated with laser-Doppler flowmetry. The SG of 15 anesthetized guinea pigs was exposed by a novel surgical approach and stimulated with a specially designed intraneural bipolar platinum-iridium electrode. Bilateral CBF was continuously monitored. Stimulation of 0.25 mA caused a detectable increase of the systemic blood pressure (BP) and a bilateral decrease of the cochlear vascular conductance (R, defined as the ratio CBF/BP). A stimulus of 0.5 mA elicited a statistically significant ipsilateral CBF (CBFi) decrease of 3.6% +/- 5.1% from the baseline and a contralateral CBF (CBFc) decrease of 3.1% +/- 5.5%. That no statistical difference was found between CBFi and CBFc indicates that a unilateral sympathetic stimulation of the SG can cause equal bilateral responses. These responses were accompanied by a significantly increased BP (8.7% +/- 5.2% of baseline) and consequently a greatly decreased R (12.2% +/- 6.5%) of the ipsilateral cochlea. Bilateral sections of the cervical sympathetic trunk below the level of the superior cervical ganglion did not alter the evoked changes in CBF, BP, and R. It is concluded that SG stimulation can decrease the conductivity of the cochlear vessels or the supplying vessels of the cochlea. Additionally, the SG nerve fibers that cause these effects do not pass through the superior cervical ganglion.

Animals↗
PubMed1993

Effects of electrical stimulation of the superior cervical ganglion on cochlear blood flow in guinea pig.

It has been proposed that cochlear blood flow (CBF) is controlled in part by the sympathetic nervous system. In the present study the effect of electrical stimulation of the superior cervical ganglion (SCG) on CBF in guinea pigs was investigated using laser Doppler flowmetry (LDF). Animals were anesthetized with diazepam and fentanyl and the SCG was exposed. A custom-designed bipolar cuff electrode was fixed around the ganglion and 1 ms biphasic current pulses were injected at 0.15 mA to 1.5 mA, 6 Hz. Bilateral CBF was monitored, while the ganglion was stimulated for 3 or 5 min before and after the ascending sympathetic trunk and nerve branches from SCG were sectioned. Electrical stimulation of 0.5 mA caused the ipsilateral CBF (CBFi) to decrease 11.7% +/- 1.3 from the baseline (BL), while the contralateral CBF (CBFc) increased slightly due to the change in systemic blood pressure (BP). A linear relation was observed between the level of current stimulation and evoked reduction in CBF. Cervical sympathetic trunk section (between the SCG and the middle cervical ganglion) did not influence the pattern or the amplitude of CBF change in response to electrical stimulation of SCG. Sectioning the efferent fibers of the medial inferior and medial superior branch of the SCG only minimally reduced the amplitude of the CBF decrease evoked by electrical stimulation. However, sectioning the superior lateral branch abolished this decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Muscle pathology in idiopathic cricopharyngeal dysphagia. Enzyme histochemical and electron microscopic findings.

The structural changes in the cricopharyngeal muscle (CM) were examined ultrastructurally and by enzyme histochemistry in five patients suffering from idiopathic cricopharyngeal dysphagia (ICD). Diagnosis was established by fiberoptic esophagoscopy, esophageal manometry and cineradiography. Cricopharyngeal myotomy was performed with marked improvement in all patients. Intraoperatively, a biopsy was taken from the CM. Additionally, all patients underwent neurological examination for possible generalized muscle disease, and a biopsy was taken from a limb muscle. CM from nine cadavers without known history of dysphagia served as control. The control samples disclosed structural changes which were considered to be pathological in other skeletal muscles, and required that the criteria for CM pathology we modified accordingly. In three patients changes in CM histology suggested specific pathogenesis: one patient had evidence for a generalized myositis but was only symptomatic for dysphagia. Another patient had muscle fiber atrophy and slight inflammation in her CM, possibly due to alcohol abuse. The third patient had loss of CM fibers with replacement by connective tissue enough to cause functional disturbances. In two patients no cause for dysphagia was found in either immunohistochemistry or electron microscopic studies. These results demonstrate the special structural features of the CM and indicate that ICD can have multiple etiologies.

Adenosine Triphosphatases↗
PubMed1992

Experimental basis for lidocaine therapy in cochlear disorders.

In order to further our basic understanding of the effects of lidocaine hydrochloride in the inner ear, cochlear potentials and blood flow (CBF) were assessed after intravenous (i.v.), anterior inferior cerebellar artery (AICA), and local round window (RW) lidocaine administrations in guinea pigs and rats. Lidocaine RW applications produced a dose dependent decrease in compound action potentials (CAP) and cochlear microphonics (CM). The sensitivity changes were more pronounced at high frequencies. These findings suggest that lidocaine has specific pharmacological action in the inner ear other than simple anesthesia of the auditory nerve. The basal turn endocochlear potentials (EP) were not altered by topical lidocaine, implicating altered organ of Corti function following local application of lidocaine. RW applications of lidocaine had no effect on CBF or systemic blood pressure (BP). I.v. infusions caused substantial reductions in BP. In the case of systemic infusions the percent changes in CBF were equal to and accountable by the BP changes. The microinfusions (50 mg/ml, 100 nl/min) through AICA produced a 30%, long lasting increase in CBF. However, neither systemic lidocaine nor AICA infusions had an effect on CAP or CM. These findings indicate that systemically given lidocaine may not cross the blood-cochlear barrier and that the cochlear electrophysiological effects due to lidocaine when given locally are partly mediated by direct influence on cochlear hair cell function; they also suggest that lidocaine-induced interference with active ion transport in the lateral wall or an influence on CBF are not contributing factors.

Action Potentials↗
PubMed1992

Peripheral facial palsy caused by Borrelia burgdorferi and viruses in south-western Finland.

In a prospective study from 1983 through 1984, 77 patients (31 men and 46 women with a mean age of 47 +/- 20 years) with peripheral facial palsy of primarily unknown etiology were investigated. Only 2 patients with acute otitis media received antibiotics. Serology of the patients was investigated on days 1 and 14. IgG and IgM antibodies against herpes simplex, varicella-zoster and cytomegalovirus were determined by enzyme immunoassay, and against Epstein-Barr virus by immunofluorescence. In a retrospective analysis, IgM, IgA and IgG antibodies against Borrelia burgdorferi were determined by enzyme immunoassay. Borreliosis was diagnosed in 5 patients and varicella-zoster infection in 7. There was no statistically significant difference in recovery time between the different groups. Follow-up time for the patients with borreliosis was over 5 years. Neither meningeal symptoms nor polyneuropathy was observed in the patients with borreliosis even in the absence of antibiotic therapy.

Adult↗