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Biomedical subjects

S Saso

Publications and source records attributed to S Saso.

At least 19 recordsLinked to original sources

[A case of complete mediastinal goiter located in the retrotracheal region: review on reported cases from 1986 to 1997 in Japan].

A 66-year-old man was admitted to our hospital as a result of an abnormal shadow which was observed on his chest X-ray. A chest CT scan and chest MRI revealed an upper mediastinal tumor. The tumor was located in the retrotracheal region and resected completely following a thoracotomy. Histological examination of the tumor revealed follicular adenoma of the thyroid gland. Complete mediastinal goiter is a relatively rare lesion, with only 59 cases (including our case) in Japan prior to 1997. Only two cases were reviewed, in which the tumors were located in the retrotracheal region, out of the 59 cases in Japan.

Adenoma↗

[Influence of age on long-term memory].

Memory for past public events having occurred between 1950-1989 was examined in Japanese subjects with average education aged forty to seventy-nine years. We compiled a public events test battery consisting of 80 multiple-choice questions regarding events, persons, or places that were prominent in the news during the four decades 1950 to 1989. With increasing age, performances of a public event test declined equivalently each decade. The effect of both age and decade was significant by three-way analysis of variance. The interaction term (age x decade) was not significant, which indicates that performance on questions relating to each decade was affected about equally by age. Performance on this test was clearly age-dependent across the time period sampled. Considering the results obtained in this study, we could conclude that aging influences very old memories as well as recent memories.

Adult↗

The auditory evoked middle-latency responses (MLRs): their normative variation and generators.

Auditory evoked middle-latency responses (MLRs) to clicks were recorded in 68 normal adults (ages from 21 to 59 year-old) at 16 scalp locations, all referred to a balanced non-cephalic reference. Both Na and Pa components were clearly demonstrated in all the subjects studied through the digital high-pass filtering. Both Na and Pa components were distributed dominantly over the frontal area in all subjects. The amplitudes of Na and Pa were significantly higher with binaural stimulation than with a monaural stimulation, and the existence of binaural interaction was also suggested. Binaural effect was more prominent in Pa than in Na component. When the data recorded from F3 and F4 electrodes were compared, most of F3/F4 amplitude ratios of Na and Pa were included between 0.7 and 1.5. The F3/F4 ratio should be useful indices for the diagnosis of excessive laterality. We also demonstrated gradual phase shifts of Na and Pa between the frontal and temporo-occipital area in about one-third of the records. This phenomenon strongly suggests that both Na and Pa components are derived from complex generators.

Acoustic Stimulation↗

Kynurenine pathway abnormalities in Parkinson's disease.

We measured metabolites of tyrosine and tryptophan (TRP) in the frontal cortex, putamen (PT), and pars compacta of the substantia nigra (SN) of control and Parkinson's disease (PD) brain tissues. Dopamine concentrations were significantly decreased in the PT and SN of PD tissue, regardless of L-dopa therapy. However, 3-O-methyldopa (3OMD) concentration showed a significant increase in each region of the PD group treated with L-dopa (PD[+]) as compared with both the control group and the PD group without L-dopa therapy (PD[-]). Therefore, 3OMD concentration appears to be a reliable marker of L-dopa therapy. Serotonin concentration was lower in each region of the PD groups than in the control group. Although the magnitude of decrease was greater in the PD(+) group, there was no statistical significance between the two PD groups. The same patterns of decrease were present in kynurenine (KYN) and kynurenic acid (KYA) concentrations, but the molar ratios of TRP to KYN and KYN to KYA were unchanged among three groups. In contrast, 3-hydroxykynurenine (3OHKY) concentration was increased in the PT PD(-) group and in three regions of the PD(+) group. Since the KYN pathway leads to formation of nicotinamide-adenine dinucleotide (NADH), the present results may be a further indication of a defect in NADH:ubiquinone oxidoreductase (complex I) in mitochondria in PD.

Aged↗

Acute effect of manidipine on renal blood flow measured by pulsed-Doppler flowmeter in normal subjects.

The purpose of this study was to examine the effect of manidipine hydrochloride, a new calcium antagonist, on renal blood flow in healthy subjects, using the newly developed pulsed-Doppler flowmeter with colored flow imager and digital computer analyzer. Results in previous studies differed because the para-aminohippurate clearance method measures the average not real-time value. Sixteen healthy volunteers (n = 7, manidipine 20 mg; n = 9, placebo control) participated in the study. Before and 1 h after drug administration, pulsed-Doppler measurements were carried out by transabdominal approach with patients in the supine position. Manidipine hydrochloride increased renal blood flow significantly compared with placebo (13.8 +/- 4.7% vs. 6.1 +/- 5.6%; p < 0.05). There was a significant (p < 0.005) between group difference in the reduction in systolic blood pressure (-14.8 +/- 1.6 mmHg manidipine; -3.0 +/- 2.1 mmHg placebo). These data suggest that manidipine hydrochloride has a vasodilating effect on renal arterioles and a beneficial effect on the kidneys of hypertensive patients. Further, the pulsed-Doppler flowmeter may become a very useful tool for noninvasive measurement of renal blood flow.

Adult↗

Unilateral spatial neglect in visual and tactile modalities.

The purpose of this study was to investigate whether a unilateral spatial neglect phenomenon occurs in the tactile modality in the absence of visual information. Ten patients with clinically confirmed visual spatial neglect and 10 normal controls bisected lines visually, or by touch when blindfolded. In visual presentation, the rightward deviation of the subjective midline was significantly more prominent in patients with visual spatial neglect than in normal controls. However, in the tactile tasks, there was no significant difference between the patient group and controls. From these results it was concluded that visual input may play an important role in the occurrence of the unilateral spatial neglect phenomenon.

Adult↗

Auditory sound agnosia without aphasia following a right temporal lobe lesion.

A 55-year-old right-handed man showed inability to recognize the meaning of non-verbal sounds without impairment of language comprehension after a cerebrovascular accident. His auditory acuity was intact and no other sign of agnosia, apraxia or aphasia was detectable. His errors on a test of sound recognition were acoustic rather than semantic. Brain CT scan showed a small lesion in the posterior part of the right temporal lobe. This case suggests that auditory sound agnosia without language disorder can ensure a lesion confined to the right hemisphere, and that the deficit is discriminative rather than associative in nature.

Agnosia↗

Effects of hand and spatial conditions on visual line bisection.

This study examined the effects of hand and spatial conditions on a visual line bisection task with normal right-handers and proposed a normal range of deviation for this task in middle and advanced age. Twenty-four normal dextrals in their fifties and sixties performed a visual line bisection task using either the left or right hand under three spatial conditions: at the midline and in the left and right hemispaces. Our results revealed that performance was significantly affected by the hand used but not spatial conditions: Left hand performance was significantly further leftward than right hand performance. There was no significant interaction between the hand and spatial conditions. The mean deviation of the right hand was 2.2% of the half line length to the right of the true center. The possibility of left unilateral spatial neglect should be considered if a patient bisects a line with a deviation greater than 10% of the half line length to the right.

Aged↗

Cognitive impairment in Parkinson's disease assessed by visuomotor performance system and P300 potential.

Motor impairment, clinically defined as bradykinesia has been considered as resulting only from motor system problems. Combined analysis of cognitive function and dynamic characteristics was studied in 20 patients with Parkinson's disease by a simple aiming task on visuomotor performance system. The dynamic characteristics in a Parkinson's disease patient was evaluated by two parameters: decreased amplitude of the voluntary movement (= low gain constant) and delayed initiation of voluntary movement (= long reaction time). The visual event-related potential elicited in a target detection paradigm (P300 component) was recorded in 12 patients with Parkinson's disease. P300 latency was significantly prolonged in the patient group than in the normal control group (p less than 0.05). P300 has been shown to be intimately related to the cognitive process in the human brain and might well serve as a tool to monitor and evaluate the cognitive state in a clinical situation. The main cause of cognitive involvement in Parkinson's disease may include coexisting dementia and defective motivation. This type of cognitive disturbance may also serve partly as a cause of bradykinesia.

Adult↗

The combination therapy with bromocriptine and cyproheptadine in patients with acromegaly.

The therapeutic efficacy of the combination of cyproheptadine and bromocriptine was studied in 15 patients with active acromegaly showing incomplete GH suppression in response to bromocriptine therapy alone. The mean basal plasma GH was 31.3 +/- 5.5 micrograms/L, and it decreased to 19.0 +/- 3.9 micrograms/L during the single bromocriptine therapy (10 to 20 mg for 2 to 21 months). When cyproheptadine (12 to 16 mg for 8 to 52 months) was added to bromocriptine therapy, plasma GH decreased further (9.4 +/- 3.0 micrograms/L: vs pretreatment, P less than 0.001; vs bromocriptine treatment, P less than 0.005), and GH normalization was obtained in 8 patients. The plasma somatomedin-C levels in these 8 patients (0.3-1.8 U/ml) were within the normal range during the combination therapy. Plasma GH responses to TRH or GHRH were markedly suppressed in 6 patients during the combination therapy compared to pretreatment or during bromocriptine treatment. In addition, a clear reduction in the tumor size was observed in 4 of 7 previously untreated patients during the combination therapy. In conclusion, cyproheptadine has therapeutic efficacy in acromegalic patients who showed incomplete GH suppression in response to treatment with bromocriptine alone. Following the cyproheptadine and bromocriptine combination therapy tumor shrinkage was observed in some patients.

Acromegaly↗

Effects of chronically administered atrial natriuretic factor in aldosterone-infused hypertensive rats.

To assess the pathophysiological role of atrial natriuretic factors in mineralocorticoid hypertension, we studied the effects of chronic infusion of synthetic atrial natriuretic factor on blood pressure and sodium-water excretion in rats with aldosterone salt-induced hypertension. Administration of synthetic atrial natriuretic factor (150 micrograms/kg/day) to rats made hypertensive by 7-day infusion of aldosterone (100 micrograms/kg/day) and sodium loading with 1% NaCl as drinking water returned the blood pressure to control levels, and the antihypertensive effect was not associated with any changes in urine volume and urinary sodium excretion. These results indicate that atrial natriuretic factors may be involved in the regulation of blood pressure in mineralocorticoid hypertension, independent of the renal effects of these substances.

Aldosterone↗

Carpal tunnel syndrome in patients on long-term hemodialysis.

Sixteen cases with carpal tunnel syndrome (CTS) were reported out of 412 patients on long-term hemodialysis due to chronic renal failure. Clinical symptoms included numbness in the area innervated by the median nerve in 100% of symptomatic hands and pain in the wrist and hand in 81%. This pain usually became severer at night and during hemodialysis. Muscle atrophy was noted in 41% of the hands. Nerve conduction studies revealed prolonged distal sensory latency, slowed sensory nerve conduction velocity across the wrist and normal distal motor latency in 18%, prolonged distal motor latency in 51% and no response in motor or sensory stimulation in 31%. Evidence of denervation on electromyography was seen in 36% of the hands. Patients were conservatively treated avoiding daily activities precipitating the condition with volar wrist splint only at night in 18% and in 90% with steroid hormone injection in the carpal tunnel. Median nerve release was performed in 18% of the hands. Amyloid deposit was demonstrated in 3 of 4 operated hands. Although the relation between long-term hemodialysis and the occurrence of the amyloid deposition in the carpal tunnel has not been established, the present data along with other recent reports strongly indicate that amyloid deposit in the carpal tunnel on hemodialysis patients could be one of the most possible cause of CTS.

Action Potentials↗

[Centro-median thalamotomy for central pain following stroke --its effectiveness and limits].

Centro-median thalamotomy was performed on 18 patients with central pain caused by cerebrovascular disease. Fourteen were males and four were females. Clinical diagnoses were thalamic pain in 17 cases including cheiro-orale syndrome in one case and phantom limb pain in one case. CT scans were performed on six recent cases. Four cases had a small low density sera in the thalamus. The other two cases had no remarkable findings. The target was 7.5-11.0 nm posterior to the middle point of the intercommissural line, 1.0 mm below-2.0 mm above that line and 5.5-10.0 mm from the midline. Unilateral lesion was made on 15 cases. Postoperatively, five cases had almost completely relief of pain and four cases had partial improvement. The duration of pain relief was, however, less than two months in four cases, and between three and seven months in four cases. One case had a pain free period for seven months. But, then, severe dysesthesia appeared. Six cases had no pain relief by unilateral lesion. Two cases had no pain relief by bilateral lesions. In the remaining case, unilateral lesion was effective for six months. Then lesion of opposite side was made, but the result was unsatisfactory. The durations from the onset of apoplectic attack to the occurrence of pain were between four months and three years in ten effective cases, and within three months in six among eight failed cases. Many surgical and medical treatments have been attempted for central pain. However, ideal method is still not appeared. Centro-median thalamotomy was effective for 56% of the patients with central pain. But in most of the cases, the duration of pain relief is about a half year at the longest. And may be, this is the limit of effectiveness of centro-median thalamotomy for central pain.

Adult↗