Postweaning Iron Deficiency in Male Rats Leads to Long-Term Hyperactivity and Decreased Reelin Gene Expression in the Nucleus Accumbens

BACKGROUND

Epidemiological research indicates that iron deficiency (ID) in infancy correlates with long-term cognitive impairment and behavioral disturbances, despite therapy. However, the mechanisms underlying these effects are unknown.

OBJECTIVE

We investigated how ID affected postweaning behavior and monoamine concentration in rat brains to determine whether ID during the juvenile period affected gene expression and synapse formation in the prefrontal cortex (PFC) and nucleus accumbens (NAcc).

METHODS

Fischer 344/Jcl postweaning male rats aged 21-39 d were fed low-iron diets (0.35 mg/kg iron; ID group) or standard AIN-93 G diets [3.5 mg/kg iron; control (CN) group]. After day 39, all rats were fed the iron-adequate diet. The locomotor activity was evaluated by the open field and elevated plus maze tests at 8 and 12 wk of age. Monoamine concentrations in the brain were analyzed using HPLC at 9 and 13 wk of age. Comprehensive gene expression analysis was performed in the PFC and NAcc at 13 wk of age. Finally, we investigated synaptic density in the PFC and NAcc by synaptophysin immunostaining.

RESULTS

Behavioral tests revealed a significant reduction of the age-related decline in the total distance traveled in ID rats compared with CN rats (P < 0.05), indicating that ID affected hyperactivity, which persisted into adulthood (13 wk of age). At this age, reelin (Reln) mRNA expression (adjusted P < 0.01) decreased and synaptic density (P < 0.01) increased in the NAcc in the ID group. Regarding the mesolimbic pathway, homovanillic acid concentration increased in the NAcc, whereas the dopamine concentration decreased in the ventral midbrain.

CONCLUSIONS

Our results suggest that ID during the postweaning period in male rats, despite complete iron repletion following ID, led to long-term hyperactivity via monoamine disturbance in the brain and an alteration in the synaptic plasticity accompanied by downregulation of Reln expression in the NAcc.

X-linked Charcot-Marie-Tooth disease type 5 with recurrent weakness after febrile illness

X-linked Charcot-Marie-Tooth disease type 5 (CMTX5) is an X-linked disorder characterized by early-onset sensorineural hearing impairment, peripheral neuropathy, and progressive optic atrophy. It is caused by a loss-of-function mutation in the phosphoribosyl pyrophosphate synthetase 1 gene (PRPS1), which encodes isoform I of phosphoribosyl pyrophosphate synthetase (PRS-I). A decreased activity leads to nonsyndromic sensorineural deafness (DFN2), CMTX5, and Arts syndrome depending upon residual PRS-I activity. Clinical and neurophysiological features of pediatric CMTX5 are poorly defined. We report two male siblings with peripheral neuropathy and prelingual sensorineural hearing loss who carried a novel c.319A>G (p.Ile107Val) PRPS1 missense mutation. They exhibited recurrent episodes of transient proximal muscle weakness, showing Gowers' sign and waddling gait after suffering from febrile illness. This transient weakness has not been previously reported in CMTX5. A patient with Arts syndrome was reported to have transient proximal weakness after febrile illness. The transient weakness presenting in both CMTX5 and Arts syndrome suggests an overlap of signs and a continuous spectrum of PRS-I hypoactivity disease. Children presenting with transient neurological signs should be evaluated for peripheral neuropathy and consider genetic analysis for PRPS1.

Remitted epilepsy with dysembryoplastic neuroepithelial tumor involving the thalamus

Dysembryoplastic neuroepithelial tumors (DNT) are benign hamartomatous tumors characterized by intractable epilepsy and common localization in the supratentorial cortex, but thalamic involvement in DNT is extremely rare. A 2-year 4-month-old boy presented with intractable epilepsy due to a tumorous lesion in the frontal lobe expanding to the thalamus. Under chronic intracranial electrocorticography guidance, partial lesionectomy with adjacent cortical resection was performed, and the lesion was pathologically diagnosed as DNT, complex form. Subsequently, the seizures completely disappeared without any neurological deficits despite the presence of full residual thalamic lesions. The epileptogenicity of DNT is closely associated with various clinicopathological factors, and the thalamic contribution to the seizure activity remains unclear. Due to the essential epileptogenic characteristics of DNT, the residual thalamic lesions and associated clinical features should be strictly observed in the future in the present case.

[Electroencephalographic characteristics in patients with febrile status epilepticus]

OBJECTIVE

This study was undertaken to investigate the electroencephalographic (EEG) characteristics in patients with febrile status epilepticus.

METHODS

Medical records and EEG findings were retrospectively examined in 14 patients with febrile status epilepticus, who were transferred to the Shiga University Hospital between November, 2009 and March, 2012.

RESULTS

Mean time to the initial EEG examination from the cessation of febrile status epilepticus was 3.4 hours. δ waves were seen in 9 of 11 patients during awake or forced awake state, and these slow waves disappeared on or after the 2nd day. Slow waves were predominantly detected in the occipital and frontal leads in 4 and 2 patients, respectively, while diffuse slowing was seen in 4 patients. Spindle/hump waves were observed in 10 of 11 patients, but not detected in the 3 patients because only awake recordings were available.

CONCLUSIONS

EEGs in the postictal state of febrile status epilepticus show slow waves, but improve early, then normal EEG sleep pattern such spindle/hump waves are commonly recognized thereafter.

Transient congenital hypothyroidism caused by biallelic mutations of the dual oxidase 2 gene in Japanese patients detected by a neonatal screening program

CONTEXT

Mutations in dual oxidase (DUOX2) have been proposed as a cause of congenital hypothyroidism. Previous reports suggest that biallelic mutations of DUOX2 cause permanent congenital hypothyroidism and that monoallelic mutations cause transient congenital hypothyroidism.

OBJECTIVE

To clarify the inheritance of hypothyroidism, we looked at the DUOX2 gene in patients with transient congenital hypothyroidism.

DESIGN

DUOX2, thyroid peroxidase, Na+/I- symporter and dual oxidase maturation factor 2 genes were analyzed in eight patients with transient congenital hypothyroidism, using the PCR-amplified direct sequencing method.

PATIENTS

The eight patients were found by a neonatal screening program. Six of these patients belonged to two independent families; the other two were unrelated. Their serum TSH values varied from 24.8-233.0 mU/liter. Six of the eight patients had a low serum freeT4 level (0.19-0.84 ng/dl). Seven of the eight patients were treated with thyroid hormone replacement therapy, which ceased to be necessary by 9 yr of age.

RESULTS

Eight novel mutations were detected in the DUOX2 gene. Four patients in one family were compound heterozygous for p.L479SfsX2 and p.K628RfsX10. Two patients in a second family were compound heterozygous for p.K530X and p.[E876K;L1067S]. The two remaining unrelated patients were also compound heterozygous, for p.H678R/p.L1067S and p.A649E/p.R885Q, respectively.

CONCLUSION

All eight patients had biallelic mutations in the DUOX2 gene. We find that loss of DUOX2 activity results in transient congenital hypothyroidism and that transient congenital hypothyroidism caused by DUOX2 mutations is inherited as an autosomal recessive trait.

Nosocomial outbreak of genetically related IMP-1 β-lactamase-producing Klebsiella pneumoniae in a general hospital in Japan

Gram-negative bacteria with acquired metallo-beta-lactamase (MBL) resistance are being increasingly described worldwide. Here we report the first case of an outbreak by a cluster of genetically related strains of Klebsiella pneumoniae producing the IMP-1 MBL. Six isolates of K. pneumoniae with a ceftazidime minimum inhibitory concentration >/=64 microg/mL were collected between February 2003 and June 2004 in Hanyu General Hospital, Saitama, Japan. These isolates were analysed to establish the mechanism of resistance. The zone of inhibition of these isolates using ceftazidime or imipenem disks on Mueller-Hinton agar containing dipicolinic acid was much larger than on Mueller-Hinton agar without dipicolinic acid. Polymerase chain reaction and DNA sequencing confirmed that the isolates contained bla(IMP-1) as well as intI1 as a class I integrase gene. Pulsed-field gel electrophoresis was performed, showing that five of the six isolates were related. This outbreak was controlled by restrained and careful use of antibiotics as well as strict hygiene practices.