Spinal cord injury (SCI) is frequently companied by necrosis and apoptosis of oligodendrocytes (OLs), which contributes to demyelination of myelinated nerve fibers and their electrophysiological defects. This pathological demyelination often results in sensory or motor deficits. Here, we first focus on the microenvironment changes after SCI that cause OLs' death, then discuss the major mechanism of endogenous oligodendrocytogenesis and axonal remyelination, and finally summarize current therapies targeting OLs protection and replacement.
Animals ; Apoptosis ; physiology ; Cell Death ; physiology ; Humans ; Necrosis ; pathology ; Nerve Fibers, Myelinated ; pathology ; Nerve Regeneration ; physiology ; Oligodendroglia ; pathology ; Spinal Cord ; physiopathology ; Spinal Cord Injuries ; pathology ; physiopathology ; therapy

BACKGROUNDMethylmalonic acidemia (MMA) is a multifactorial autosomal recessive inborn error of organic acid metabolism, often presenting with neurological symptoms. As neurological disorders are often related to white matter injury, diffusion tensor imaging (DTI) is an excellent tool for assessment of white matter injury and possibly for diagnosing this disorder.

METHODSWe retrospectively analyzed DTI images of 12 patients with MMA (7 males, 5 females, age range: 7 - 12 months, mean age: 9.25 +/- 1.70 months) with negative MRI findings. And another 12 age-matched and gender-matched infants were enrolled as control subjects. Fractional anisotropy (FA) of different white matter tracts of the brain was measured in both groups.

RESULTSFor patients with negative MRI findings, compared with healthy infants, a statistically significant reduction in DTI FA value of the frontal white matter, temporal white matter, and occipital white matter was observed (P < 0.01).

CONCLUSIONSIn addition to conventional T1W and T2W MR Image, Brain DTI presents a useful, sensitive and complementary tool for the assessment of brain damage in patients with MMA.

Amino Acid Metabolism, Inborn Errors ; blood ; pathology ; Anisotropy ; Brain ; pathology ; Diffusion Magnetic Resonance Imaging ; methods ; Female ; Humans ; Infant ; Male ; Methylmalonic Acid ; blood ; Nerve Fibers, Myelinated ; pathology

OBJECTIVETo evaluate diffusion tensor tractography (DTT) of white matter in prognosis of acute lacunar infarctions.

METHODSTwenty-eight patients of pyramidal tract strokes at the acute phase (<3 days) with a marked motor defect were examined. Lesions were identified on diffusion weighted imaging and isotropic imaging of DTI, and infarctions and the tract were shown on the DTT images simultaneously. The anatomic location and pattern of the lesions were visualized on DTT, with regard of the corticospinal tract (CST), all patients were divided into three clinical subgroups: in Group 1 infarction lesions were close to CST, in Group 2 CST was partial involved, in Group 3 lesions centered in the pyramidal tract. Subsequently, they were compared with the National Institutes of Health Stroke Scale (NIHSS) scores at acute phase (<3 days), early chronic phase (8 approximately 14 days), and outcome(30 approximately 60 days).

RESULTNIHSS scores of Group 1(12/28) were not different with those of Group 2 (11/28) at the acute phase (U=-1.430, P>0.05), and NIHSS scores in Group 2 were significantly lower than those of Group 3(5/28) (U= -2.676, P <0.01). In the outcome, NIHSS scores of Group 1 were significantly lower than those of Group 2 (U= -2.501, P<0.05), NIHSS scores of Group 2 were significantly lower than those of Group 3 (U= -2.948, P<0.01). Among these three groups,Group 1 all had good recovery, Group 2 also had good recovery but sometimes with some mild motor disfunction, and Group 3 always had marked defect and minor improvement. Both rADC value and rFA value were induced in the acute lacunar infarctions.

CONCLUSIONDTT is helpful in prognestic valuation of acute lacunar infarction by providing visualized stereo localization of CST and infarction lesions.

Brain ; pathology ; Brain Infarction ; diagnosis ; pathology ; Diffusion Magnetic Resonance Imaging ; methods ; Female ; Humans ; Imaging, Three-Dimensional ; methods ; Male ; Middle Aged ; Nerve Fibers, Myelinated ; pathology ; Prognosis

Hereditary sensory and autonomic neuropathies (HSAN) are disorders of hereditary neuropathy mainly affecting sensation and also accompanying autonomic nervous system dysfunction. They are divided into five subtypes based on inheritance pattern and clinical manifestation. Among HSAN, type II is characterized by autosomal recessive inheritance, presentation at later stage of life, slow progression and mainly sensation abnormalities. The main pathology of the peripheral nerve is the absence of myelinated nerve fibers. Type IV is very rare disorder and only a few cases have been reported. It is characterized by autosomal recessive inheritance, presentation at birth as failure to thrive, retarded motor development, unexplained pyrexia and rapidly progressive and severe clinical course. The main pathology of the peripheral nerve is a loss of unmyelinated and small myelinated nerve fibers. We report two cases of type IV and one case of type II especially focusing on ultrastructural findings, which are characteristic of and diagnostic for HSAN.
Autonomic Nervous System ; Failure to Thrive ; Fever ; Hereditary Sensory and Autonomic Neuropathies* ; Inheritance Patterns ; Nerve Fibers, Myelinated ; Parturition ; Pathology ; Peripheral Nerves ; Sensation ; Wills

Mild traumatic brain injury (mTBI) is a common type of brain disorders among young adults. The dysfunction of the brain is often exacerbated due to diffuse axonal injury (DAI) which based on the injury of white matter fibers and axons. Since mild and moderate brain injury or DAI are diffuse and subtle, conventional CT and MRI are difficult to make a positive diagnosis. Recent clinical study indicated that functional magnetic resonance imaging has a high detection rate in the diagnosis of acute mild and moderate brain injury, especially the diffusion tensor imaging (DTI) and 1H-magnetic resonance spectroscopy (1H-MRS). This paper has reviewed the principles and characteristics of DTI and 1H-MRS, and recent research in the clinical and animal experiments on brain injury.
Animals ; Axons/pathology* ; Brain/pathology* ; Brain Concussion/pathology* ; Brain Injuries/pathology* ; Diagnosis, Differential ; Diffuse Axonal Injury/pathology* ; Diffusion Tensor Imaging ; Humans ; Magnetic Resonance Spectroscopy/methods* ; Nerve Fibers, Myelinated/pathology* ; Severity of Illness Index

It is very common that increased carotid intima media thickness (CIMT) and carotid plaque coexist in a single subject in elderly patients with white matter lesions (WMLs). In this study we investigated whether the coexistence of increased CIMT and carotid plaque is more strongly associated with the presence and extent of WMLs than either alone. All patients were classified into 1 of the following 4 groups: without either increased CIMT (I) or carotid plaque (P): I(-)P(-); with only increased CIMT: I(+)P(-); with only carotid plaque: I(-)P(+); and with both increased CIMT and carotid plaque: I(+)P(+). The presence and severity of periventricular WMLs (PWMLs) and deep WMLs (DWMLs) were assessed and the prevalence of MRI findings by the Cochran-Armitage trend test was calculated. The characteristics of subjects showed that the percentages of patients with increased CIMT and carotid plaque in the DWMLs group and the PWMLs group were significantly higher than those without WMLs group. Both DWMLs and PWMLs were strongly associated with age, carotid plaque and CIMT. Furthermore, the Cochran-Armitage trend test indicated that the prevalence of MRI findings of PWMLs and DWMLs increased in the order of I(-)P(-)< I(+)P(-)< I(-)P(+)< I(+)P(+) (P<0.0001). For the patients with DWMLs, the grades of both I(+)P(-) and I(+)P(+) were increased significantly compared to I(-)P(-) (P<0.0025, P<0.05, respectively) without such a difference found in patients with PWMLs. Our results suggested that the coexistence of increased CIMT and carotid plaque is most closely associated with WMLs, and that increased CIMT is associated with the severity of DWMLs, whereas carotid plaque is related to the presence of WMLs.
Aged ; Aged, 80 and over ; Brain ; pathology ; Carotid Intima-Media Thickness ; statistics & numerical data ; Carotid Stenosis ; diagnostic imaging ; pathology ; Female ; Humans ; Male ; Nerve Fibers, Myelinated ; pathology ; Reproducibility of Results ; Sensitivity and Specificity ; Statistics as Topic

We reviewed dinical, histological and ultrastructural findings of 124 cases of sural nerve biopsy specimens to delineate the trends of peripheral nerve diseases in our institute. Eighty-one were men and 43 were women. We categorized them into five groups: specific diagnosis (66 cases, 53.2%), axonal degeneration type (47 cases, 37.9%), demyelinating type (4 cases, 3.2%), mixed axonal degeneration-demyelinating type (6 cases, 4.8%) and normal (1 case, 0.9%). Cases with specific diagnosis included 21 inflammatory demyelinating polyneuropathy (15 chronic inflammatory demyelinating polyradiculoneuropathy, 6 Guillain-Barre disease), 13 hereditary motor and sensory neuropathy (7 Charcot-Marie-Tooth type I, 6 Charcot-Marie-Tooth type II), 10 vasculitis, 6 toxic neuropathy, 4 leprosy, 3 diabetic neuropathy, 2 alcoholic neuropathy, 1 Fabry's disease and other specific diseases (5 cases). In our cases, the proportion of specific diagnoses was higher, while the proportion of demyelinating peripheral neuropathies and normal were lower than those of Western series. The results of this study indicate that 1) a dose clinicopathologic correlation is important to make a precise diagnosis of peripheral nerve biopsy, 2) Biopsy under strict indication may reduce unnecessary histologic examination, 3) There is no difference in disease pattern of peripheral neuropathy between Western people and Koreans.
Adult ; Biopsy ; Charcot-Marie-Tooth Disease/pathology ; Demyelinating Diseases/pathology ; Fabry Disease/pathology ; Female ; Hereditary Motor and Sensory Neuropathies/pathology ; Human ; Korea ; Leprosy/pathology ; Male ; Microscopy, Electron ; Nerve Fibers, Myelinated/pathology ; Peripheral Nerves/ultrastructure ; Peripheral Nerves/pathology ; Peripheral Nervous System Diseases/pathology* ; Peripheral Nervous System Diseases/microbiology ; Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/pathology ; Sural Nerve/ultrastructure ; Sural Nerve/pathology*

OBJECTIVETo explore the pharmacodynamic and pathological mechanism of eucommia ulmoides oliv in improving erectile function.

METHODSThirty male diabetic rats were randomly divided into three groups: group A (n = 10, escipient group), group B (n = 10, sildenafil group), group C (n = 10, eucommia ulmoides oliv group) and group D (n = 10, the normal control group). After gavage for four weeks, the catching behaviors of all rats were observed, and ultrastructure of myelinated nerve fibers in penile tissue was examined by transmission electron microscope. The expression of neuronal nitric oxide synthase (nNOS) in penile tissues was examined by two steps immunohistochemistry method.

RESULTSCompared with group A, catching frequency of the rats in group C was notably increased (P < 0.05) and the expression of nNOS in penile tissue was significantly (P < 0.001). The examination by transmission electron microscope showed that in the rats' penile tissue of group A, myelinated nerve fibers were irregularly arranged and partially degenerated, and myelin sheaths lamella were splited and exhibited vacuoles or network forms. In group C, there were regular arrangements of myelinated nerve fibers, in which the formation of lamella was clear.

CONCLUSIONBy remitting the impairement of myelinated nerve fibers and enhancing the expression of nNOS in penile tissue, eucommia ulmoides oliv can improve erectile function of diabetic rats.

Animals ; Behavior, Animal ; drug effects ; Diabetes Mellitus, Experimental ; pathology ; physiopathology ; Drugs, Chinese Herbal ; pharmacology ; Eucommiaceae ; Female ; Immunohistochemistry ; Male ; Microscopy, Electron, Transmission ; Nerve Fibers, Myelinated ; ultrastructure ; Nitric Oxide Synthase ; metabolism ; Penis ; drug effects ; enzymology ; innervation ; Random Allocation ; Rats ; Rats, Sprague-Dawley