Long-term nonpassaged EGF-responsive neural precursor cells are stem cells

We have screened lines of nonpassaged epidermal growth factor-responsive neurospheres from embryonic striatum and brainstem. They have been maintained in defined medium with epidermal growth factor over a period of 2 years and remained in an undifferentiated state to this date. Since isolation from the brain 2 years ago, these nonpassaged epidermal growth factor responsive neurospheres have shown active proliferation and self-renewal capacity. When subplated on a poly-D-lysine coated surface, they resumed differentiation within 24 hours. The differentiation process of the nonpassaged epidermal growth factor responsive neurosphere appeared to recapitulate the neural development in the brain. Many cells migrated, extending radial processes while expressing nestin and S100 in the early 7-day subplating culture. They continued to differentiate into major neural types in 14-day subplating culture, including fibrous and cytoplasmic astrocytes, oligodendrocytes, and serotonin, gamma-aminobutyric acid, and a small number of tyrosine hydroxylase-positive neurons. The nonpassaged epidermal growth factor-responsive neurospheres in many ways resemble hemopoietic cells. Both are proliferative, possess the potential of indefinite self-renewal, yet multipotent, and are capable of resuming the differential pathway. The nonpassaged epidermal growth factor responsive neurospheres meet the criteria of stem cells and have been found to be a useful model to study the development in vitro.

Constructing a new nigrostriatal pathway in the Parkinsonian model with bridged neural transplantation in substantia nigra

The physical repair and restoration of a completely damaged pathway in the brain has not been achieved previously. In a previous study, using excitatory amino acid bridging and fetal neural transplantation, we demonstrated that a bridged mesencephalic transplant in the substantia nigra generated an artificial nerve pathway that reinnervated the striatum of 6-hydroxydopamine (6-OHDA)-lesioned rats. In the current study, we report that a bridged mesencephalic transplant can anatomically, neurochemically, and functionally reinstate the 6-OHDA-eradicated nigro-striatal pathway. An excitatory amino acid, kainic acid, laid down in a track during the transplant generated a trophic environment that effectively guided the robust growth of transplanted neuronal fibers in a bundle to innervate the distal striatum. Growth occurred at the remarkable speed of approximately 200 microm/d. Two separate and distinct types of dopamine (DA) innervation from the transplant have been achieved for the first time: (1) DA innervation of the striatum, and (2) DA innervation of the pars reticularis of the substantia nigra. In addition, neuronal tracing revealed that reciprocal connections were achieved. The grafted DA neurons in the SNr innervated the host's striatum, whereas the host's striatal neurons, in turn, innervated the graft within 3-8 weeks. Electrochemical volt- ammetry recording revealed the restoration of DA release and clearance in a broad striatal area associated with the DA reinnervation. Furthermore, the amphetamine-induced rotation was attenuated, which indicates that the artificial pathways were motor functional. This study provides additional evidences that our bridged transplantation technique is a potential means for the repair of a completely damaged neuronal pathway.

Morphological Differentiation of Astroglial Progenitor Cells from Egf-Responsive Neurospheres in Response to Fetal Calf Serum, Basic Fibroblast Growth Factor, and Retinol

Procurement of multipotential neuroglial stem cells is possible with the addition of epidermal growth factor (EGF). Stem cells will differentiate into neurons and glia upon the removal of EGF from the culture medium. We have previously characterized the neuronal differentiation of stem cells derived from long-term cultured nonpassage neurospheres. In the current study, we (1) characterize the morphological differentiation of the astroglial progenitor cell from 3-mo-old neurospheres, (2) examine whether the astroglial progenitor cells from neurospheres of different brain areas exhibit different differentiation responses to the same exogenous signals, and (3) test the effects of basic fibroblast growth factor (bFGF) and retinol on differentiation. Cerebral cortex, striatum, and mesencephalon cells were obtained from Embryonic Day 14 (E-14) rat fetuses and were dissociated for the procurement of neurospheres in chemically defined medium supplemented with EGF. After 3 mo in culture, the neurospheres, derived from each of the three brain areas, were subcultured into three groups on chamber slides: (1) basal medium, (2) the basal medium plus 20 ng/mL bFGF, and (3) the basal medium plus 10 μM retinol. Phenotypic expression of astroglial cells was examined after 14 days subculture. Our findings indicate that the 3-mo-old cultured nonpassage neurospheres contained numerous multipotential stem cells that stained positive with nestin, and that environmental factors played an important role in influencing the differentiation of astroglial progenitor cells. As detected by glial fibrillary acid protein (GFAP), astroglial progenitor cells turned into protoplasmic astrocytes in the FCS-containing basal medium, fibrous astrocytes in the presence of bFGF, and spindle-shaped astrocytes in the presence of retinol. There were no noticeable differences in differentiation among astroglial progenitor cells of the various brain region-derived neurospheres in any of the three medium conditions. Peculiar varicosity-and growth cone-like structures on the long slender GFAP-positive processes suggest that neuroblasts and glioblast may share common morphologies, features, or common progenitor cells during initial differentiation in vitro.

Isovolemic hemodilution normalizes the prolonged passage of red cells and plasma through cerebral microvessels in the partially ischemic forebrain of rats

The objective of this study was to determine whether hemodilution could normalize the mean transit times of red blood cells (Tr) and plasma (Tp) through cerebral microvessels in a partially ischemic brain. Wistar-Kyoto (WKY) rats, aged 30-40 weeks, were divided randomly into three groups. The first group was the nonocclusion, nonhemodilution (NN) normal control group. The second group was the occlusion, nonhemodilution (ON) group, in which animals were treated with bilateral carotid artery ligation. The third group was the occlusion-hemodilution (OH) group, in which animals were treated with bilateral common carotid artery ligation and, then, isovolemic hemodilution by replacing blood with the same volume of 3% modified fluid gelatin. Local cerebral blood flow (lCBF) and microvascular volumes of red blood cells (Vr) and plasma (Vp) in 14 brain structures were measured using 14C-iodoantipyrine, iron-55 labeled red blood cells, and 14C-inulin, respectively. The amount of oxygen delivered to local brain structures (OD), cerebral microvascular blood volume (Vb), mean transit time of blood (Tb), Tr, and Tp through cerebral microvessels were calculated from the data. Two hours after carotid artery ligation, lCBF decreased by approximately 38% in forebrain structures, 22% in rostral hindbrain areas, and 8% in the caudal hindbrain (29% for all 14 structures). The decreases in ODs were parallel with those of lCBFs, at 33, 17, and 2% in the three regions, respectively (24% for all structures). In contrast, Vb increased by 68, 37, and 16% in the three regions, respectively (48% for all structures). Tr and Tp were markedly prolonged (180% for Tr and 154% for Tp) in the forebrain regions, moderately (91% for Tr and 73% for Tp) in the rostral hindbrain, and mildly (60% for Tr and 13% for Tp) in the caudal hindbrain, with a mean increase of 136% for Tr and 111% for Tp in all structures. When data in the OH and NN groups were compared, lCBF values tended to be slightly higher and Vb values were significantly higher (p < 0.05) in the OH group. ODs in the eight forebrain structures were all significantly less (p < 0.05) in the OH group than the NN group. Tr and Tp values in the forebrain were similar between the OH and the NN groups. In conclusion, occlusion of the bilateral common carotid arteries in WKY rats causes partial forebrain ischemia, in which both Tr and Tp are prolonged. These prolongations of Tr and Tp can be normalized by isovolemic hemodilution. However, the ischemic forebrain remains hypoxic after hemodilution.

Pineal ganglioglioma with premature thelarche. Report of a case and review of the literature

We report a case of a 6-year-old girl with a ganglioglioma in the pineal region presenting with a rare clinical picture of premature thelarche. Intracranial gangliogliomas are rare, especially in the pineal region. Their character, origin, treatment, and prognosis remain controversial. The pathophysiology of precocious puberty associated with pineal ganglioglioma is discussed.

Hemodilution accelerates the passage of plasma (not red cells) through cerebral microvessels in rats

BACKGROUND AND PURPOSE

Hemodilution lowers the total circulatory red cell mass and blood viscosity and thereby may alter the time of passage of red cells and plasma through cerebral microvessels. This study was designed to clarify this question.

METHODS

Adult Wistar-Kyoto rats, aged approximately 32 weeks, were divided into hemodilution and control groups. Local cerebral blood flow and microvascular red cell and plasma volumes in 14 brain structures were measured with the use of [14C]iodoantipyrine, 55Fe-labeled red cells, and [14C]inulin, respectively.

RESULTS

In the control group, the hematocrit in cerebral microvessels ranged from 0.29 to 0.45 with a mean of 0.36, which was 71% of the systemic hematocrit (0.51). The mean transit times of blood, red cells, and plasma through microvessels were 0.62 to 1.77 seconds (mean, 0.92 second), 0.44 to 1.15 seconds (mean, 0.65 second), and 0.78 to 2.5 seconds (mean, 1.25 seconds), respectively. In the hemodilution group, the mean hematocrit in microvessels was 0.28, which was 89% of the systemic hematocrit (0.32). Local cerebral blood flow was approximately 59% higher (P < .01) than that of the control animals. The rate of oxygen delivered to the brain was slightly increased (9%) after hemodilution. Blood volume in cerebral microvessels was similar to that of the control group. Mean transit time of blood was 0.62 second (68% of the control), transit time of red cells was 0.53 second (85% of the control), and transit time of plasma was 0.67 second (54% of the control).

CONCLUSIONS

These findings indicate that isovolemic hemodilution accelerates the plasma (not red cell) flow velocity in cerebral microvessels.

Excitochemical-induced trophic bridging directs axonal growth of transplanted neurons to distal target

Brain grafts directly placed in their target regions often lack proper connections and normal regulation. When brain grafts are placed in their ontogenetic normal area, the axonal outgrowth of grafts to distal target regions is a major obstacle. We previously demonstrated that directional axonal growth of grafts can be facilitated by laminin. In this study we demonstrated that excitochemicals induced trophic environment can be strategically used as a bridge to guide transplanted neurons to innervate a distal target of millimeter distance, and has a unique effect on fiber expansion in the target region. To distinguish dopamine (DA) growth from that of transplants, 6-hydroxydopamine was unilaterally injected into medial forebrain bundle to remove dopamine innervation to the striatum. Ibotenic acid (IB), kainic acid (KA), or phosphate buffer (vehicle) were microinjected through a glass-pipet to make a 7 mm long tract between the substantia nigra and the striatum in Sprague-Dawley rats. Gestational 14-15 days brainstem slurry was transplanted either in the same or a separate tract into nigra at the bottom of the bridge. All transplants survived with abundant serotonin (5-HT) and DA neurons. Traceable DA fibers formed distinct bundles from grafts along the length of IB/KA tracts. Upon arrival at their major target regions, fibers from bundles were capable of leaving the tracts, and reinnervating the DA-vacated striatum. The 5-HT fibers formed bundles similar to DA fibers but left the tract earlier upon arrival at their major target the globus pallidus and when arriving at the striatum and cortex. Fibers from grafts with vehicle tracts grew randomly and not into the tract. These results indicate that the trophic effects of chemical lesioning serves as a remarkably effective axonal guidance for more than one type of fetal neuron to innervate distal brain regions. This method has great potential in directing fibers in many transplant models.

A simple method for diagnosing traumatic occlusion of the vertebral artery at the craniovertebral junction

STUDY DESIGN

A simple method, thin-slice contrast-enhanced computed tomographic (CT) scan, was evaluated as a first-line rapid screening procedure for diagnosing traumatic occlusion of the vertebral artery at the craniovertebral junction.

OBJECTIVES

This procedure was performed in patients suffering from injuries of the high cervical spine or the craniovertebral junction. Vertebral angiography was undertaken after this procedure to confirm the diagnosis.

SUMMARY OF BACKGROUND DATA

Well-enhanced vertebral arteries can be demonstrated clearly in normal subjects by using this method. Occlusion of the vertebral artery produces delayed contrast enhancement of the proximal artery and abrupt interruption of its course.

METHODS

Thin-slice CT scan was performed from the atlas to the occipital condyles after an intravenous injection of angiograffin. The plane of the CT scan was aligned in a parallel manner to the upper margin of the atlas. The CT scanning was repeated until the contrast enhancement of the vertebral arteries became faint.

RESULTS

Occlusion of the unilateral vertebral artery was successfully diagnosed in a patient with Jefferson's fracture by using the present technique. A subsequent vertebral angiography confirmed the diagnosis.

CONCLUSIONS

The present technique should be performed as a routine screening procedure in patients suffering from injuries to the craniovertebral junction.

Combined treatment with nicardipine, phenobarbital, and methylprednisolone ameliorates vasogenic brain edema

Free radicals formed around the edematous areas of the brain can cause lipoperoxidation of the cellular membrane, followed by calcium influx into the cell through calcium channels. These secondary insults may aggravate vasogenic brain edema. Since phenobarbital is a free radical scavenger, methylprednisolone has an antilipoperoxidation effect; and nicardipine is a calcium channel blocker, we hypothesized that combined treatment with phenobarbital, methylprednisolone, and nicardipine would be beneficial in vasogenic brain edema. This hypothesis was tested in Sprague-Dawley rats with a transdural cold-injury on the right parietal cortex. The animals were randomly divided into two groups. Animals in the treatment group were injected intraperitoneally with phenobarbital (4 mg/kg), methylprednisolone (50 mg/kg), and nicardipine (10 micrograms/kg) at 5 min and 8 hours after the cold-injury. The control animals were injected with saline. These animals were sacrificed 24 hours after the injury. The extent of brain edema was assessed by measuring the water content, the inulin distribution volume, and the distribution area of Evans blue in the brain. Our results showed that the water content of the edematous hemisphere was similar in the control and the treatment groups. However, Evans blue distribution area and inulin distribution volume of the treatment group were less than those of the control group by 12% and 31%, respectively. In conclusion, the combined treatment with phenobarbital, methylprednisolone and nicardipine is beneficial in vasogenic brain edema.

Transdural cortical stabbing facilitates the drainage of edema fluid out of cold-injured brain

Recent experimental results indicate that cerebral glia lining and glia limitans may be barriers for plasma protein extravasated from injured cerebral microvessels flowing into the adjacent subarachnoid space. Therefore, it has been hypothesized that a transdural cortical stabbing which opens both the pia lining and glia limitans may facilitate drainage of edema fluid into the subarachnoid space and minimize brain edema. This hypothesis was tested in Sprague-Dawley rats with a transdural cold-injury on the right parietal cortex. The animals were sacrificed 24 hours later. One hour before being sacrificed 0.6 ml of 2% Evans blue was intravenously injected to determining the Evans blue distribution area. For measuring the inulin retention volume in the brain, 14C-inulin (10 microCi) in 1 ml of saline was injected intravenously at 10 min before sacrifice. The extent of brain edema was assessed by measuring the water content, the inulin retention volume, and the distribution area of Evans blue in the brain. Our results showed that the transdural cortical stabbing did not alter the water content of the cerebral hemisphere with cold lesion. However, it did effectively diminish the inulin retention volume by 26% as well as the distribution area of Evans blue by 22% in the cerebral hemisphere with cold lesion. In conclusion, a transdural cortical stabbing on the injured cortex may be beneficial for vasogenic brain edema.

Enterogenous cyst of the fourth ventricle: case report

The authors present an intracranial enterogenous cyst of the fourth ventricle in a Chinese woman having symptoms of headache, dizziness and vertigo for approximately six months. A computerized tomography study of the brain disclosed a low density lesion within the fourth ventricle. A cystic tumor was completely removed and a histopathological examination diagnosed it is an enterogenous cyst; a rare lesion. During the post-operative follow-up, her symptoms gradually resolved and she was free of complaints within two years.