Hyperlipidaemia in patients with Down's syndrome.

Plasma lipid levels were measured in 20 mongoloid and 16 non-mongoloid mentally retarded subjects. Significant elevations of plasma triglyceride levels were found in patients with Down's syndrome compared with mentally retarded controls. However, no significant difference was found in plasma cholesterol, phospholipid and free fatty acid levels between the mongoloids and control subjects.

Effects of rat ventral and dorsal hippocampus temporal inactivation on delayed alternation task.

To determine the involvement of the hippocampal regions in a operant-type delayed alternation task of short delay or long delay, microinjections of muscimol into the hippocampus were used for temporal inactivation during the behavioral test in each rat. Dorsal hippocampal inactivation impaired the correct ratio of long delay. Ventral hippocampal inactivation showed no changes in the correct ratio, however, it increased the tendency of perseveration in long delay. These findings suggest hippocampus has regional differentiation in delayed alternation task.

Effects of rat medial prefrontal cortex temporal inactivation on a delayed alternation task.

To determine the involvement of the medial prefrontal cortex (mPFC) in operant-type delayed alternation, microinjections of muscimol into the mPFC were used for temporal inactivation during behavioral tests in rats. The temporal mPFC inactivation showed effects related to both dorsal (decreased delay-dependent correct ratio, indicating working memory-related deficits) and ventral hippocampus inactivation (increased tendency to repeat errors) reported in our recent paper, without motor or sensory effects. These findings suggest that the mPFC integrates information from different hippocampal regions during a delayed alternation task.

Magnetic resonance imaging and clinical findings examined in adulthood-studies on three adults with Rett syndrome.

PURPOSE: To clarify magnetic resonance imaging (MRI) findings in three adult patients with Rett syndrome who had been diagnosed with mental retardation and autism. METHOD: Clinical and MRI findings in three adult cases with Rett syndrome were studied. Ages (in years) in three adult cases with Rett Syndrome were 46 in Case 1, 35 in Case 2 and 20 in Case 3. They were able to walk and their convulsions were well controlled. RESULTS: MRI findings in all patients showed mild cerebral atrophy, especially in the frontal and temporal lobes and two of the cases also had mild cerebellar atrophy. One case also showed a narrowing of the brainstem and thinning of the corpus callosum. CONCLUSIONS: These results indicate that abnormalities in MRI imaging, in cases where there is narrowing of the brainstem and thinning of the corpus callosum, may be due to congenital hypoplasia. It was also seen that cerebellar atrophy became more distinct in older cases.

Vomiting attack with ACTH and ADH discharge improves startle epilepsy.

A 15-year-old boy with sequelae of perinatal asphyxia experienced intractable startle-induced epileptic seizures, which were transiently suppressed with episodic vomiting. His vomiting was associated with adrenocorticotropin and antidiuretic hormone discharge, and the alteration of urinary catecholamine excretion, which might modulate epileptic seizures. Because startle-induced epileptic seizures are resistant to conventional antiepileptic therapy, this case is informative for the treatment of startle epilepsy.

Electrophysiological brainstem dysfunction in a child with Leigh disease.

We evaluated brainstem dysfunction in a girl with Leigh disease. Neuroradiological and neurophysiological tests included brain magnetic resonance imaging, [123I]IMP single-photon emission computed tomography (SPECT), auditory brainstem responses (ABRs), short-latency somatosensory evoked potentials (SSEPs), electrically elicited blink reflexes (BRs) and all night polysomnography (PSG). The basal ganglia and midbrain contained areas of low accumulation on [123I]IMP SPECT images. Serial analysis of ABRs and SSEPs showed progressive disturbances of the brainstem wave components. The R2 components of the BRs were impaired. All night PSG revealed disturbances in both the tonic and phasic components of REM sleep. These findings suggested the multimodality tests in combination with neuroradiologic examinations are useful for assessing brainstem dysfunction in patients with Leigh disease.

[A case of multiple pterygium syndrome (Escobar) with horseshoe kidney].

We report a 25-year-old male with multiple pterygium syndrome (Escobar) complicated with a horseshoe kidney. He had clinical characteristics of Escobar syndrome, including palpebral ptosis, auricular anomalies, pterygia with contracture of the elbow and knee joints, syndactyly and polydactyly of the feet, and growth failure. Renal scintigraphy and abdominal MRI and CT demonstrated a horseshoe kidney, which was thought to be an incidental association. He had no auditory brainstem response, but he could respond to sounds of low-frequency and the voices of familiar persons. Neither brain MRI and CT nor SPECT demonstrated any abnormalities. Further neurophysiological and neuroradiological studies are necessary to elucidate neurological deficits in this syndrome.

Differences in paired-pulse facilitation and long-term potentiation between dorsal and ventral CA1 regions in anesthetized rats.

To clarify hippocampal regional differences in synaptic plasticity, paired-pulse facilitation (PPF, a form of short-term plasticity), long-term potentiation (LTP, a form of long-term plasticity), and their interactions were studied in the dorsal and ventral hippocampal CA1 regions of anesthetized rats. Baseline PPF and post-LTP PPF experiments were conducted at interstimulus intervals (ISIs) of 20-320 ms. A general protocol (100 Hz, 1 s) and a stronger protocol (250-Hz pulse series) were applied for LTP induction. PPF were observed in both regions; however, the degree was lower and the range of ISIs was narrower in the ventral region compared with the dorsal region. The degree of ventral LTP was lower than that of the dorsal LTP. The interaction between PPF and LTP was observed in both regions (PPF change correlated inversely with degree of baseline PPF). However, this was also different in each region. Dorsal PPF increased or decreased; in contrast, ventral PPF of short ISIs after LTP only decreased. These regional differences in short-term and long-term synaptic plasticity may explain a consequence of different afferent inputs and information processing.

Renal impairment in urate excretion in patients with Down's syndrome.

Uric acid and creatinine clearance studies were performed in nine subjects with Down's syndrome and in eight mentally retarded controls. The urate clearance was significantly decreased in subjects with Down's syndrome compared with controls. Their mean creatinine clearances were also significantly lower than the controls. No significant differences were shown in erythrocyte lactate dehydrogenase activity, in blood lactate and in blood beta-hydroxybutyrate levels between 20 subjects with Down's syndrome and 16 controls. Glomerular dysfunction would seem to contribute to hyperuricemia in Down's syndrome.

Association of increased numbers of peripheral blood double-negative T-lymphocytes with elevated serum IgG levels in severely handicapped children.

CD3+4-8- double negative cells in peripheral blood lymphocytes were examined in 21 severely handicapped children divided into two groups according to serum IgG level. All children were bedridden and were taking multiple anticonvulsants and there were no apparent clinical differences between these two groups. Serum levels of IgG correlated well with percentages of CD3+4-8- double negative lymphocytes in patients of both groups. In comparisons between the two groups, the high IgG group had higher counts of CD3+4-8- double negative lymphocytes in peripheral blood than the normal IgG group. Two distinct types of double negative cells were identified in the patients with high IgG: one had T-cell antigen receptors of gamma delta heterodimers, the other had receptors of alpha beta chains on their surface. As double negative T-cells are reported to have an important role in defence against bacterial infections, the increased numbers of CD3+4-8- T-cells of both phenotypes in the high IgG patients may reflect exposure to repetitive bacterial stimuli or persistent subclinical infection which in many cases, may be undetectable clinically. Moreover, the hyperimmune states shown by the high serum IgG of these patients may result from the appearance of these unique lymphocytes because they are reported to have a helper function for IgG synthesis in vitro. Taken together, the increased numbers of double negative cells in patients with high IgG may reflect activated defence mechanisms and the development of hyperimmune status.

Synthesis and concentration of 5-phosphoribosyl-1-pyrophosphate in erythrocytes from patients with Down's syndrome.

Plasma urate levels and erythrocyte glucose-6-phosphate dehydrogenase activity were not significantly different in patients with Down's syndrome when compared with control subjects with mental retardation. No significant difference was found in 5-phosphoribosyl-1-pyrophosphate (PRPP) concentration and synthesis of PRPP in erythrocytes from glucose between subjects with Down's syndrome and controls. The purine metabolism of Down's syndrome is discussed.

Abnormal serum immunoglobulin levels in Down's syndrome patients.

Serum immunoglobulin levels were measured in 20 patients with Down's syndrome and 16 mentally retarded cerebral palsy control patients. Significant elevation of IgG and IgD levels were found in the Down's syndrome as compared with the control patients. Serum IgD level in Down's syndrome individuals significantly decreased with increasing age. Serum IgA level was significantly elevated in older Down's syndrome patients but showed no change in younger Down's syndrome patients. Serum IgM and IgE levels were slightly elevated in Down's syndrome patients, but these differences were not significant. The elevated immunoglobulin levels in Down's syndrome individuals seem to be a response to increased frequency of infection.

Serum lymphocytotoxins and lymphocyte responses to mitogens of Down syndrome person.

Lymphocyte responses to phytohemagglutinin P (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) and incidence of serum lymphocytotoxins in 20 Down syndrome persons were investigated. There was no change in lymphocyte blastogenesis to mitogens in younger Down syndrome individuals (less than 30 years of age) as compared to control persons. The lymphocytes of Down syndrome subjects over 30 years of age showed significantly decreased responses to PHA, Con A, and PWM. Results suggest that with increasing age, Down syndrome persons seem to have an impairment in lymphocyte function. Serum lymphocytotoxins that were not related to age occurred in 4 of the Down syndrome subjects (20 percent). There was no correlation between the presence of lymphocytotoxins and lymphocyte blastogenesis in these subjects.