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Biomedical subjects

T Rahko

Publications and source records attributed to T Rahko.

At least 19 recordsLinked to original sources
PubMed2000

Reduction of carbon tetrachloride-induced hepatotoxic effects by oral administration of betaine in male Han-Wistar rats: a morphometric histological study.

Eighty-five male Han-Wistar rats were arranged into three groups: CCl4-exposed rats, CCl4 + betaine-exposed rats, and control rats. To see the effect of betaine alone, five rats of the control and of the CCl4 + betaine groups were sacrificed after 7 days, before exposure to CCl4. After that, two of the groups (the CCl4 and CCl4 + betaine groups) were exposed to CCl4 (1 ml/kg per day subcutaneously [SC] for 4 consecutive days), and one of the groups (control group) was given olive oil (1 ml/kg per day SC for 4 consecutive days). At the start of the study (day 0), day 1, day 2, day 3, day 4, and 3 days after the last CCl4 and olive oil injections (day 7), samples of five rats per group were sacrificed, and the livers were taken for chemical analyses and histological examination. Oral betaine, after the acclimation period of a week, increased the number of mitochondria but not mitochondria size (day 0), compared with the case in control rats. Exposure to CCl4 resulted in centrilobular hepatic steatosis, and the administration of betaine significantly reduced this. Morphometric analyses also revealed that the addition of betaine increased the volume density of rough endoplasmic reticulum (RER) in the perinuclear areas of liver cell cytoplasm (day 7). Additionally, the administration of betaine prevented the reduction of Golgi complexes and mitochondrial figures in the cytoplasm observed after the exposures to CCl4. Also, the volume density of mitochondria was smallest in the CCl4-group, but the difference was not statistically significant. The results indicate that oral betaine either improves recovery or reduces the toxic effects of CCl4 on cell organelles in liver cells of male Han-Wistar rats.

Administration, Oral↗
PubMed1999

Diagnostic value of tympanometry in infants in clinical practice.

One hundred and twenty-one visits of 58 infants (2-11 months of age) were evaluated in the Finnish Otitis Media Vaccine Trial. Infants were examined with tympanometry (Grason-Stadler GSI 38 Autotymp) and pneumatic otoscopy by one study doctor. Diagnosis of otitis media was verified by myringotomy in 74% of cases. Tympanometry was technically successful in 94% of ears. The success rate was statistically significantly higher (P < 0.05) among infants less than 7 months of age than those above 7 months. The sensitivity of tympanometry (type B) to detect ears with middle ear fluid was 0.70 and the specificity 0.98 with a positive predictive value of 0.93 and negative predictive value of 0.94. The sensitivity was somewhat lower in the younger age group (0.61); specificity and positive and negative predictive values were good in both age groups. The high success rate and high negative and positive predictive values of tympanometry make it a useful aid for assuring the correct diagnosis of otitis media in infants in routine clinical practice.

Acoustic Impedance Tests↗
PubMed1998

Betaine reduces hepatic lipidosis induced by carbon tetrachloride in Sprague-Dawley rats.

Carbon tetrachloride-injected rats were given liquid diets with and without betaine for 7 d. Hepatic lipidosis was induced by 4 daily injections of carbon tetrachloride (CCl4). Animals were killed and their livers and blood taken for analysis of betaine, S-adenosylmethionine (SAM), betaine homocysteine methyltransferase (BHMT), triglyceride, alanine aminotransferase and aspartate aminotransferase. Liver samples were also processed and stained for histological examination. Supplemental betaine reduced triglyceride in the liver and centrilobular hepatic lipidosis induced by the CCl4 injections. In both the control and experimental groups receiving betaine, liver betaine, BHMT and SAM were significantly higher than in their respective groups not receiving betaine. This study provides evidence that betaine protects the liver against CCl4-induced lipidosis and may be a useful therapeutic and prophylactic agent in ameliorating the harmful effects of CCl4.

Administration, Oral↗
PubMed1997

A new analysis method for the evaluation of transient evoked otoacoustic emissions.

An analysis system with the Matlab 4.2 system with a filter bank is presented that provides graphically created 2D and 3D views of responses in the frequency, time and amplitude coordinates. Smoothed spectral and noise responses are presented. The start end and maximum TEOAE amplitude latencies are presented graphically and calculated numerically. The fast Fourier transformation (FFT), filter bank and wavelet transforms were developed and compared for the TEOAE analysis purposes.

Acoustic Stimulation↗
PubMed1997

Comparison of carbogen inhalation and intravenous heparin infusion therapies in idiopathic sudden sensorineural hearing loss.

The effect of carbogen (5% carbon dioxide and 95% oxygen) inhalation and intravenous heparin on sudden sensorineural hearing loss was compared. Forty-four patients received the former, 43 the latter treatment, respectively. The patients were unselected patients of the clinic. The PTA (0.5-2.0 kHz) at the pretreatment stage was 62 dB in the heparin and 55 dB in the carbogen group. One month later the corresponding figures were 34 and 32 dB, the difference being statistically not significant. Thus neither of these methods proved superior in the treatment of sudden sensorineural hearing loss.

Administration, Inhalation↗
PubMed1997

Tinnitus treatment by transcutaneous nerve stimulation (TNS).

Twenty-six patients were treated with transcutaneous nervous stimulation (TNS) for tinnitus. Except for 3 normal hearing patients, all had cochlear hearing losses. Tinnitus disappeared in none, but diminished in 7 cases against 3 in 24 nontreated controls. In the controls there were no reliefs in low-frequency tinnitus cases. One of these 7, who reported benefit initially, used the TNS system for several months. It seems that TNS is not as good as expected, but probably in cases where the tinnitus frequency is low and it disappears with TNS totally, the patients may use it.

Audiometry↗
PubMed1995

Diet-induced residual formation in pigs.

Six piglets, aged 4 weeks (weaning) at the beginning of the experiment, were fed a diet lacking antioxidants (vitamin E and selenium) and enriched with oxidated cod liver oil (the peroxide value of which was 112.54 meqv/kg). Four of the experimental pigs were killed for necropsy at the age of 2 months and the remaining two pigs at the age of 3 months. Two piglets from the same litter served as controls. Myodegeneration of the skeletal muscles was induced in the experimental group. The livers were pale and mottled. Light microscopy revealed degenerative alterations in the heart and skeletal muscle and infiltrations by lipidic substances. The ultrastructure of some lipidic droplets was analogous to those of ceroid and lipofuscin. Peroxisomes were frequent in degenerating hepatocytes. In order to elucidate the lysosomal involvement in the residual formation, light and electron microscopical immunocytochemistry using copper-zinc superoxide dismutase (CuZnSOD), was applied. Probably zinc was recruited into the antioxidant protection concluding upon the increased erythrocyte superoxide dismutase (E-SOD) activity.

Aging↗
PubMed1995

Hearing and acute otitis media in 13-year-old children.

Air and bone conduction thresholds of 330 unselected urban 13-year-old children with a known history of otitis were measured under ideal conditions, using standard clinical audiometry. In the subgroups of children with different numbers (0, 1-2, 3-7, > or = 8) of attacks of acute otitis media (AOM) in their history, the mean air conduction thresholds varied from 0.2 to 11.5 dB at different frequencies in different AOM subgroups. Air conduction pure tone averages (PTA, mean threshold at 0.5, 1 and 2 kHz) > 20 dB were not found in any of the ears. The mean bone conduction thresholds varied from -0.0 to 1.8 dB, depending on the subgroup and frequency (0.25 to 4.0 kHz) studied. Bone conduction PTAs > 10 dB were measured in 5 (0.8%) ears. Single bone conduction thresholds > 10 dB were found at different frequencies in 3 to 15 (0.5 to 2.3%) of the ears, and thresholds > 20 dB in only 2 ears (0.3%). The mean thresholds and number of ears with decreased hearing were distributed equally between different AOM subgroups, except that some air conduction high frequency losses were more frequent in children with > or = 8 attacks of AOM. We conclude that childhood AOM, even if it occurs frequently, seems not to have a significant harmful long-term effect on hearing.

Acute Disease↗
PubMed1994

Diet-induced lipofuscin and ceroid formation in growing pigs.

Seven piglets, aged 2 weeks at the beginning of the experiment, were fed a diet lacking antioxidants (vitamin E and selenium) and enriched with thermally oxidated cod liver oil (the peroxide value of which was 310 meqv/kg). From one month before to 4 weeks after farrowing (weaning) the sow also received the experimental diet. One pig died at 9 days of age, due to degeneration of the parenchymal tissues. The oxidative stress produced was aggravated in four of the seven remaining pigs by giving them an injection of iron-dextran (300 mg) one day before the animals were killed for necropsy at the age of 2 months. The three other piglets were given an injection of a control saline solution. The nutritional myodegeneration produced ('white muscle disease') was characterized by a pale, yellowish colour and translucence of skeletal muscle, with degeneration, including swelling of the muscle fibres and slackening of the fibrillar pattern. The arrangement of nuclei in chains indicated repair. Ultrastructurally, skeletal muscle showed vacuolization of the sarcoplasmic reticulum, irregularities in the mitochondria and focal dissolution of myofibrils. The sarcoplasmic reticulum displayed condensation and lamellar formations. Hyaline degeneration of the heart muscle occurred both in iron-treated and control pigs, and in six animals a yellowish pigment resembling lipofuscin and ceroid was observed. Ultrastructurally, the ceroid deposits appeared as myelin-like figures. The livers were pale and brittle, four with centrilobular degeneration. By light microscopy, lipidosis was distinguished in four and ceroid accumulations in three pigs. Thiobarbituric-acid-reactive substances, creatine kinase activity and iron increased significantly in the serum as a result of the injection of iron-dextran.

Animal Feed↗
PubMed1991

TCDD decreases rapidly and persistently serum melatonin concentration without morphologically affecting the pineal gland in TCDD-resistant Han/Wistar rats.

The highly toxic environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was recently reported to decrease serum melatonin levels throughout the circadian cycle in the most TCDD-susceptible strain of rat, Long-Evans. To find out whether this effect is related to the mechanism of acute lethality of TCDD, serum melatonin levels were measured at the nocturnal peak phase in the most TCDD-resistant rat strain variant, Han/Wistar rats, 6 hr to 28 days after TCDD exposure. The same dose as used in the previous study, 50 micrograms/kg, decreased serum melatonin levels to approximately half the control values by the first day after the treatment. Melatonin concentrations remained at this reduced level over the whole observation period. In an auxiliary experiment, Han/Wistar rats were dosed with 1000 micrograms/kg TCDD and killed on day 3. Neither light nor electron microscopic examination of their pineal glands revealed any alteration attributable to TCDD treatment. These findings might indicate that the reduction of serum melatonin levels in the rat by TCDD is not related to its lethal effect and is not due to a direct damage of the pineal gland.

Animals↗
PubMed1990

Low- and high-frequency hearing in patients with Menière's disease.

We determined the pure-tone hearing thresholds of 25 patients with unilateral active Menière's disease using standard clinical audiometry, high-frequency audiometry (10-18 kHz), and low-frequency audiometry (20-80 Hz). In addition to hearing loss at the conventional frequencies, all of the affected ears showed deterioration of the thresholds at both low- and high-frequency areas as compared with the reference ears. The degree of hearing loss at these frequencies correlated to the degree of the hearing loss at the conventional frequencies, where it was greatest at 0.5-1 kHz. Our findings suggest that in Menière's disease the whole cochlear sensory area is affected, and that the damage caused by Menière's disease advances simultaneously in all parts of the cochlea.

Audiometry↗
PubMed1989

Pure-tone hearing thresholds in otologically healthy 5-year-old children in Finland.

We measured the pure-tone air and bone conduction hearing of 359 randomly selected otologically normal urban preschool children in Finland at the average age of 5.2 years. Children with otoscopically verified middle ear pathology or abnormal impedance audiometry were not included in this sample. The mean air conduction thresholds varied from 16.6 dB at 0.125 kHz to 6.6 dB at 2 kHz, and the mean bone conduction thresholds from 6.0 dB at 0.25 kHz to 0.7 dB at 4 kHz. The pure-tone average (of air conduction thresholds at 0.5, 1 and 2 kHz) of all the ears was 7.6 dB. The distribution of single air conduction hearing thresholds at the frequencies from 0.25 kHz to 4 kHz showed that 66%-75% were at the 5-10 dB level.

Auditory Threshold↗
PubMed1989

Evaluation of the hearing loss associated with cis-platinum treatment by high-frequency audiometry.

The effect of cis-platinum treatment on the hearing of 23 ovarian cancer patients was evaluated using standard and high-frequency audiometry. Twenty-two percent of the patients developed a hearing loss of at least 15 db, 13% in the range 125-8000 Hz and 9% only in the high-frequency area above 8 kHz. However, due to the high-frequency hearing loss (presbyacusis) in older patients high-frequency audiometry was often unobtainable. Hearing screening using standard pure-tone audiometry is recommended for cis-platinum patients as a routine procedure.

Adult↗
PubMed1989

Hearing and hearing loss in 5-year-old children. Pure-tone thresholds and the effect of acute otitis media.

Air and bone conduction pure-tone thresholds of 420 unselected urban children were measured with standard clinical audiometry. The mean of air conduction pure-tone averages (average threshold at 0.5, 1 and 2 kHz) was 8.6 dB HL in girls and 8.3 dB HL in boys. In only 5 ears (0.6%), was this average greater than or equal to 35 dB HL. The threshold greater than or equal to 35 dB HL at 4 kHz was found in 1.4% of the ears and at 8 kHz in 4.1%. The bone conduction threshold greater than 20 dB HL at any of the frequencies from 0.5 to 4 kHz was very rare, and only once, at 4 kHz, was it greater than 35 dB HL. Earlier attacks of acute otitis media seemed to have only a marginal long-term effect on air conduction hearing, and an almost negligible effect on bone conduction hearing.

Acute Disease↗
PubMed1989

Pancreatic enzyme supplementation in normal and exocrine pancreatic insufficient pigs.

The effect of pancreatic enzyme preparation (Combizyme Forte granulate) on the growth rate of normal, sham-operated and pancreatic duct ligated growing pigs was studied in 2 trials. In the first trial 6 normal Yorkshire pigs were fed a pancreatic enzyme supplement and 6 other pigs from the same litter were fed without supplementation. The growth rate over a period of 4 weeks was not significantly greater in the supplemented group. In a second trial exocrine pancreatic insufficiency, without diabetic symptoms, was produced in 12 pigs (aged 1.5 months and weighing 14 kgs) by ligation of the main pancreatic duct. The growth rates over a period of 20 days after surgery were 240 g, 454 g and 483 g/day in ligated pigs, in ligated pigs supplemented with pancreatic enzyme and in sham-operated control pigs, respectively. The difference between the ligated groups was significant (p less than 0.01) indicating the efficiency of the pancreatic enzyme therapy.

Amylases↗
PubMed1988

The prevalence of handicapping hearing loss in a middle-aged population in Finland.

Screening audiometry was performed during the years 1973-1978 in a total of 11,744 subjects aged 35-50 years. The incidence of those persons having a mean hearing threshold of 30 dB or more at 0.5-2 kHz or of 50 dB or more at 2 kHz varied from 0.3% to 2.7% in males of different age subgroups. The results for females were about two-thirds of those for males. Overall, 1.5% of the Finnish population aged 35-54 years were found to be candidates for hearing rehabilitation.

Adult↗
PubMed1988

High frequency audiometry in facial paralysis.

High frequency (10-21 kHz) hearing thresholds were measured in 54 patients with Bell's palsy. In 25 (46%) of the patients the high frequency hearing was worse in the affected side, and in 16 (30%) better. The differences in the mean threshold between the two ears varied from 17.1 to 3.8 dB, being statistically significant at half of the frequencies measured. The findings support the idea that facial palsy is one manifestation of a lesion which extends beyond the VIIth cranial nerve.

Audiometry↗