The loss of GluR2(3) immunoreactivity precedes neurofibrillary tangle formation in the entorhinal cortex and hippocampus of Alzheimer brains

Double-immunolabeling techniques were employed to examine the distribution of GluR2(3) subunits and markers of early cytoskeletal changes (mab MC1) within the entorhinal cortex (EC) and hippocampus of cases with varying degrees of Alzheimer disease (AD) pathology (stages I-VI by Braak and Braak). In addition near-adjacent tissue sections were double-immunolabeled using antibodies against GluR2(3) and a marker of normal neuronal cytoskeleton (MAP2). In those cases classified as stages I-II, most layer II neurons of the EC and pyramidal neurons in the CA1/subiculum were double-labeled with GluR2(3) and MAP2. An occasional MC1-labeled cell was observed, yet in no instance were these neurons double-labeled with GluR2(3). In cases with moderate AD pathology (stages III-IV), layer II of the EC and CA1/subiculum were characterized by a substantial loss of GluR2(3)-labeled neurons, while many were still immunoreactive to MAP2. Notably, the loss of GluR2(3) immunolabeling was accompanied by an increasing number of MC1-positive neurons. In no instance were GluR2(3) and MC1 co-localized within the same neuron. In cases with severe AD pathology (stages V-VI), the EC and CA1/subiculum were almost completely devoid of GluR2(3)-positive neurons. MAP2-labeled neurons also were reduced in number. In contrast, both regions contained an abundance of MC1-positive cells. That GluR2(3) and MC1 are not observed in the same neuron, together with the observation that the number of GluR2(3)-labeled neurons decreases as the number of MC1-positive cells increases, suggest that a loss of GluR2(3) immunolabeling precedes the appearance of MC1 immunolabeling.

Isolation of subpopulations of high density lipoproteins: three particle species containing apoE and two species devoid of apoE that have affinity for heparin

We have isolated and partially characterized five populations of lipoproteins from the pool of immunoisolated apoA-I-containing lipoproteins obtained from normal human plasma. The first three populations, each containing apoA-I and apoE, were isolated completely by sequential, selected affinity immunosorption against apoA-I and apoE. The lipoproteins isolated by this strategy fall into three morphologic groups; there are discs (LP-AI-E(1)), small spherical lipoproteins (LP-AI-E(2)), and large spherical lipoproteins (LP-AI-E(3)). The LP-AI-E(2) species was sufficiently abundant for detailed characterization. They have slightly larger diameters, and contain more lipid than the bulk of apoA-I-containing lipoproteins and they contain apoA-II:E heterodimers and apoE homodimers. Core lipids are enriched in triglyceride relative to cholesteryl esters. These lipoproteins compete with LDL equally, on a protein mass basis, for binding to human fibroblasts. After removal of apoE-containing lipoproteins from the pool of apoA-I-containing lipoproteins, we discovered two additional subpopulations of lipoproteins that bind to heparin. These lipoproteins, devoid of apoE, occur as populations of small, (LP-AI-HB(1)), and large, spherical lipoproteins, (LP-AI-HB(2). The heparin-binding lipoproteins were separated by gel permeation chromatography. The LP-AI-HB(1) population was of sufficient quantity for detailed study. These lipoproteins also had larger diameters than the bulk of HDL but their core lipids were enriched in cholesteryl esters rather than triglycerides. Three proteins associated with these lipoproteins were found to bind to heparin-Sepharose in the absence of lipid. The approximate molecular weights of these proteins are 40, 70, and 90 kDa. The 70 kDa molecule was found to be the SP 40,40 protein (apoJ).

Autologous hapten-modified melanoma vaccine as postsurgical adjuvant treatment after resection of nodal metastases

PURPOSE

To determine whether treatment with an autologous whole-cell vaccine modified with the hapten dinitrophenyl (DNP vaccine) is an effective postsurgical adjuvant treatment for melanoma patients with clinically evident nodal metastases.

PATIENTS AND METHODS

Eligible patients had regional nodal metastases that were large enough (> or = 3 cm diameter) to prepare vaccine. Following standard lymphadenectomy, patients were treated with DNP vaccine on a monthly or weekly schedule.

RESULTS

Of 62 patients with metastasis in a single lymph node bed (stage III), 36 are alive after a median follow-up time of 55 months (range, 29 to 76); the projected 5-year relapse-free and overall survival rates are 45% and 58%, respectively. Of 15 patients with metastases in two nodal sites, five are alive with a median follow-up time of 73 months. An unexpected finding was the significantly better survival of older patients; the projected 5-year survival of patients greater than 50 versus < or = 50 years was 71% and 47%, respectively (P = .011, log-rank test). The development of a positive delayed-type hypersensitivity (DTH) response to unmodified autologous melanoma cells was associated with significantly longer 5-year survival (71% v 49%; P = .031). Finally, the median survival time from date of first recurrence was significantly longer for patients whose subcutaneous recurrence exhibited an inflammatory response (> 19.4 v 5.9 months; P < .001).

CONCLUSION

Postsurgical adjuvant therapy with autologous DNP-modified vaccine appears to produce survival rates that are markedly higher than have been reported with surgery alone. Moreover, this approach has some intriguing immunobiologic features that might provide insights into the human tumor-host relationship.

Melanoma of unknown primary site: presentation, treatment, and prognosis--a single institution study. University of Pennsylvania Pigmented Lesion Study Group

BACKGROUND

A retrospective analysis of 40 patients diagnosed with melanoma of unknown primary site (MUP) was undertaken to analyze the etiology and clinical behavior of this presentation.

METHODS

The patient records were located by a computer search of the Pigmented Lesion Clinic data base at the University of Pennsylvania. With the Cox proportional hazards model, the survival of the MUP patients with lymph node presentation was compared with that of patients with lymph node disease and a known concurrent primary melanoma.

RESULTS

Sixty-five percent of the patients presented with lymph node metastasis only, 28% presented with visceral lesions, and 8% presented with subcutaneous nodules. The prevalence of dysplastic nevi was 22.5%. The overall 4-year survival rate for the 40 MUP patients was 55% +/- 9%. The 4-year survival (57% +/- 12%) of patients with lymph node presentation was compared with that of patients presenting with lymph node disease and a known concurrent primary melanoma (19 +/- 6%). Survival was significantly different between the groups (P = 0.008). This survival difference remained significant (P = 0.02) even after adjustments for number of positive lymph nodes, year of diagnosis, and age at diagnosis.

CONCLUSIONS

This analysis revealed that MUP patients with lymph node metastasis survived significantly longer than patients diagnosed with lymph node metastasis concurrent with a known cutaneous primary melanoma. The prevalence of dysplastic nevi in the MUP patient series was intermediate between that reported among primary melanoma patients and that reported among population controls, suggesting the likelihood of a primary cutaneous origin for the metastatic melanoma.

Oxygen transport with oscillations of inspired oxygen concentration

A theoretical model predicts that forced inspiratory oxygen concentration oscillations can be used to recover cardiorespiratory data and elicit information about the oxygen transport system (Hahn, 1996). The effects of hypoxia on the penetration of these generated oxygen oscillations into arterial and venous blood were explored in dogs exposed to a graded severity of hypoxia. Continuously recorded sinusoidal oxygen oscillations in the respired partial pressure, blood tension and mixed-venous saturation show that the transmission of forced oxygen oscillations from the lungs to the arterial blood depends on the mean arterial saturation. When mean inspired oxygen is high enough to fully saturate arterial haemoglobin, an inspired oscillation can only be transmitted in the blood as an oscillation in oxygen tension. However, in the presence of arterial hypoxaemia, oscillations in both the oxygen saturation and partial pressure of arterial blood are observed. Under these conditions, the oxygen saturation and partial pressure oscillations are also transmitted to mixed-venous blood. Our data illustrates that the link between the arterial and mixed-venous oscillations is non-linear and dependent on the sigmoidal binding relationship between oxygen and haemoglobin.

Extraordinary conservation of cysteines among homologous Chironomus silk proteins sp185 and sp220

Aquatic larvae of the midge, Chironomus tentans, synthesize a 185-kDa silk protein (sp185) with the cysteine-containing motif Cys-X-Cys-X-Cys (where X is any residue) every 20-28 residues. We report here the cloning and full-length sequence of cDNAs encoding homologous silk proteins from Chironomus pallidivittatus (sp185) and Chironomus thummi (sp220). Deduced amino acid sequences reveal proteins of nearly identical mass composed of 72 blocks of 20-28 residues, 61% of which can be described by the motif X5-8-Cys-X5-(Trp/Phe/Tyr)-X4-Cys-X-Cys-X-Cys. Spatial arrangement of these residues is preserved more than surrounding sequences. cDNA clones enabled us to map the genes on polytene chromosomes and identify for the first time the homolog of the Camptochironomus Balbiani ring 3 locus in Chironomus thummi. The apparent molecular weight difference between these proteins (185 vs 220 kDa) is not attributable to primary structure and may be due to differential N-linked glycosylation. DNA distances and codon substitutions indicate that the C. tentans and C. pallidivittatus genes are more related to each other than either is to C. thummi; however, substitution rates for the 5'- and 3'-halves of these genes are different. Blockwise sequence comparisons suggest intragenic variation in that some regions evolved slower or faster than the mean and may have been subjected to different selective pressures.

Proliferation index as a predictor of prognosis in malignant gliomas of childhood

BACKGROUND

The prognosis for children with high grade gliomas remains somewhat unpredictable because histologic features alone provide an imperfect assessment of the biologic behavior of a given lesion. Whereas some patients experience prolonged disease control after surgery and adjuvant therapy, others with lesions that appear comparable exhibit rapid disease progression and death.

METHODS

Because proliferative activity may provide a potential correlate of biologic aggressiveness, the authors examined the relationship between MIB-1 labeling index and outcome in a series of 29 archival pediatric malignant nonbrainstem gliomas from patients treated consecutively at the study institution between 1975 and 1992, in which clinical, histologic, diagnostic, and therapeutic parameters were previously defined. Three patients who died perioperatively were excluded from outcome analyses. All tumors were rereviewed by two neuropathologists and classified as Grade 3 or 4 lesions based on contemporary guidelines.

RESULTS

Among the specimens from the 26 patients who survived the perioperative period, a striking difference in outcome was apparent between tumors with MIB-1 indices < 12 (n = 10) and those with indices > 12 (n = 16). Median progression free survival was >48 months in the low MIB-1 group compared with only 6 months in the high MIB-1 group (P = 0.014, rank-sum test). Median overall survival was >48 months in the low MIB-1 group compared with only 16 months in the high MIB-1 group (P = 0.012). MIB-1 index remained associated with survival after taking into account the effect of resection extent, which also correlated strongly with outcome in this cohort. Although MIB-1 index was associated with histopathologic grade (Grade 3: 11.9 +/- 9.7 vs. Grade 4: 27.3 +/- 19.0; P = 0.015, Fisher's exact test), it proved to be a much stronger predictor of outcome than histology.

CONCLUSIONS

MIB-1 index may supplement routine histologic classification as a means for improving the accuracy of predicting the biologic behavior of childhood malignant gliomas and may provide a basis for stratifying patients in future malignant glioma studies and refining therapeutic decision-making.

Controlled pilot study of rapid amphotericin B infusions

This pilot study compared the toxicity of a one hour with a four hour amphotericin B infusion in children. There were more severe chills in the former group on the first day of infusion, and more hypotension in the latter group over the study duration.

The relationship between TP53 mutations and overexpression of p53 and prognosis in malignant gliomas of childhood

The prognosis for children with high-grade gliomas remains somewhat unpredictable. Although prolonged disease control is sometimes achieved after surgery, radiotherapy, and chemotherapy, most patients exhibit rapid disease progression. Because p53-dependent apoptosis mechanisms are involved in the cytotoxic effects of irradiation and chemotherapy, we questioned whether p53 status might be associated with outcome in childhood malignant gliomas. Therefore, we examined p53 status, both immunohistochemically and by direct sequencing of exons 5-8, in a series of 29 archival pediatric malignant non-brainstem gliomas treated consecutively at our institution between 1975 and 1992. Eighteen tumors had dense p53 staining in the majority of cells, although only 11 had mutations of the p53 gene (TP53). On univariate analysis, there was a significant association between p53 overexpression and a shorter progression-free survival (PFS) and overall survival (OS; P = 0.019 and 0.013, respectively; rank sum test). In addition, there was a significant association between TP53 mutations and a poorer PFS (P = 0.04), and a strong trend toward a shorter OS among patients with TP53 mutations (P = 0.06). Median PFS and OS for patients with TP53-mutated tumors were 6 months and 16 months, respectively, and for those with p53 overexpression 5.5 months and 14 months, respectively, versus 16 months and 25 months, respectively, for those without TP53 mutations and 25 months and >4 years, respectively, for those without p53 overexpression. The percentage of patients in this series with TP53 mutations (37.9%) was substantially higher than in previous studies of childhood gliomas and comparable to the frequency of mutations noted in adult gliomas. However, both TP53 mutation and p53 overexpression were significantly less frequent in tumors from children younger than 4 than from older children (P = 0.02 and 0.01, respectively). These results indicate that p53 mutation and expression status may be associated with prognosis in childhood malignant gliomas, and thus may provide a basis for stratifying patients biologically in future malignant glioma studies.

A model of diffuse traumatic brain injury in the immature rat

Diffuse cerebral swelling after severe traumatic brain injury (TBI) develops more commonly in children than adults; however, models of diffuse brain injury in immature animals are lacking. The authors developed a new model of diffuse severe TBI in immature rats by modifying a recently described closed head injury model for adult rats. A total of 105 Sprague-Dawley immature rats (17 days old; average weight 38.5 +/- 5.46 g) were subjected to head impact using variable weights (0 g (sham), 75 g, 100 g, or 125 g) delivered from a height of 2 m onto a metal disk cemented to the intact cranium. Mortality, physiological and neurological parameters (from early reflex recovery to escape), and early histopathological changes were assessed. During the acute period after severe injury (SI) (100 g delivered from a height of 2 m; 50 rats), apnea was frequently observed and the mortality rate was 38%. Neurological recovery was complete in the sham-injured animals (11 rats) by 4.1 +/- 0.23 minutes (mean +/- standard error of the mean), but was delayed in both moderately injured (MI) (75 g/2 m; 11 rats) (14.97 +/- 3.99 minutes) and SI (20.57 +/- 1.31 minutes (p < 0.05)) rats. In the first 24 hours, the sham-injured animals were more active than the injured ones as reflected by a greater net weight gain: 2.9 +/- 1.0 g, 1.2 +/- 1.6 g, and -0.6 +/- 2.1 g in sham-injured, MI, and SI animals, respectively. Immediately after injury, transient hypertension (lasting < 15 seconds) was followed by hypotension (lasting < 3 minutes) and loss of temperature regulation. Both injuries also induced apnea (0.75 +/- 0.7 minutes and 1.27 +/- 0.53 minutes in MI and SI groups, respectively), which either resolved or deteriorated to death. Intubation and assisted ventilation in animals with SI for 9.57 +/- 3.27 minutes in the peritrauma period eliminated mortality (p < 0.05, intubated vs. nonintubated). Histologically, after SI, there was diffuse edema throughout the corpus callosum below the region of injury and in the thalami. Other injuries included neuronal death in the deep nuclei, bilateral disruption of CA3, diffuse subarachnoid hemorrhage, and, in some, ventriculomegaly. Following a diffuse TBI in immature rats, SI produced a mortality rate, neurological deficit, and histological changes similar to those previously reported for an injury resulting from a 450-g weight dropped from 2 m in adult rats. A graded insult was achieved by maintaining the height of the weight drop but varying the weights. Weight loss, acute physiological instability, and acute neurological deficits were also indicative of an SI. Mortality was eliminated when ventilatory support was used during the peritrauma period. This model should be useful in studying the response of the immature rat to diffuse severe TBI.

Case of the month. May 1996--hydrocephalus in a 9 month old infant

A 9 month old infant presented with hydrocephalus. MRI studies revealed a large cystic space with a nodule that was bright on T-1 weighted images and dark on T-2 weighted images. It was bright with contrast enhancement. The surgical specimen was noted to be dark black. Microscopic examination revealed a benign papillary tumor consistent with a choroid plexus papilloma which was heavily pigmented with melanin. Immunohisto-chemical stains were consistent with a choroid plexus papilloma, but they also showed many epithelial cells to be positive for HMB-45. Ultrastructural studies demonstrated melanosomes and pre-melanosomes in cells with well-delineated basal lamina. This is the first case to demonstrate melanosomes in a benign choroid plexus papilloma. Previously reported cases of pigmented lesions of the choroid plexus either contained neuromelanin in the benign examples or melanosomes in two cases of choroid plexus carcinomas.

A meningeal cyst of the thoracic spine presenting as prolonged paresis after ankle injury: case report

A case of a thoracic meningeal cyst causing right lower extremity weakness in a fifteen-year-old girl is presented. The diagnosis was delayed due to a history of ankle injury which was initially used to explain her symptoms. The authors explain the difficulty in diagnosing intraspinal meningeal cysts and stress the importance of surgical excision before spinal cord injury progresses.

Measurement of respiratory parameters by using inspired oxygen sinusoidal forcing signals

A companion paper (C. E. W. Hahn. J. Appl. Physiol 81: 985-997, 1996) described a continuous-flow gas-exchange mathematical model, which predicted that forced inspired oxygen sinusoids could be used to measure respiratory parameters rapidly, in place of the inert gas argon. We therefore made simultaneous measurements of dead space volume (VD) and alveolar volume (VA) in an animal model, using argon and oxygen inspired gas concentration sinusoid forcing signals, and then compared the results. Our data confirmed the model prediction that the attenuations of the oxygen and argon sinusoid perturbations are identical in the alveolar gas space, even though there is a net uptake of oxygen by the body. Our results show that the calculated values of VD and VA, obtained by using inspired oxygen forcing signals, were independent of both the mean fractional inspired oxygen concentration (FIO2; range 0.18-0.80% vol/vol) and the oxygen forcing signal amplitude (range +/- 2-6% vol/vol). In these studies, oxygen forcing signals, with forcing periods between 1 and 2 min, were able to measure controlled changes in instrument dead space to within 16 ml and also measure positive end-expiratory pressure-induced changes in VA. Under hyperoxic conditions, intravascular oxygen sensors confirmed that the sinusoidal PO2 signal passed into the arterial blood but not into the mixed-venous blood. However, the sinusoid perturbation PO2 signal did pass into the mixed-venous blood when the mean FIO2 was mildly hypoxic (FIO2 = 0.18% vol/vol). These data show that oxygen can be used instead of argon to measure airways dead space and VA.

Unusual case of inflammatory spinal epidural mass (Castleman syndrome)

Castleman syndrome (giant lymph node hyperplasia) is a rare, heterogeneous lymphoproliferative disorder of unknown etiology and pathogenesis. Most cases occur as mediastinal masses, although extrathoracic involvement including nodal and extranodal locations have been reported. The localized variants (solitary lesions) respond well to surgical excision. We report a 10-year-old boy who presented with headache, intermittent fever, and progressive weakness of his legs. MRI imaging showed an enhancing epidural mass with impingement on the spinal cord at the C6-T2 level. Other laboratory abnormalities included anemia, hypergammaglobulinemia, increased erythrocyte sedimentation rate, and cerebrospinal fluid pleocytosis with slightly increased cerebrospinal protein. The mass was partially resected and the histopathology showed lymphoplasmocytic infiltration compatible with Castleman syndrome. There was no evidence of malignancy. Castleman syndrome is the most likely diagnosis in the presence of the associated systemic findings, although the epidural site for lymphoplasmocytic inflammation is atypical.

Immunohistochemical staining of fixed tissue using antigen retrieval and a thermal cycler

The use of monoclonal antibodies to identify antigens in perfused fixed tissue is currently very challenging. Recently, many antigen retrieval methods have been described that require heating the tissue on slides using a microwave oven. Here, we describe a protocol for antigen retrieval that uses a commercially available solution called Citra and a DNA thermal cycler to heat the tissue sections. This method (i) allows for precise control of the temperature and time (unlike the microwave oven), (ii) uses very small quantities of the antigen retrieval solution, (iii) stains either free-floating sections or sections mounted on slides and (iv) achieves uniform staining throughout the tissue. In the paraformaldehyde-perfused fixed rat cerebellum, the monoclonal antibody glial fibrillary acidic protein conveys the clarity of the Bergmann and stellate glia in the strata. Scanning confocal images through the center of the tissue demonstrates the depth of antibody penetration achieved using this method. Finally, using a monoclonal antibody against the simian virus 40 (SV40) T antigen allowed positive, unequivocal identification of a grafted cell line, immortalized using SV40 T protein, thus demonstrating the true value of this method in an experimental paradigm.

Expression of tyrosine hydroxylase in an immortalized human fetal astrocyte cell line; in vitro characterization and engraftment into the rodent striatum

The use of primary human fetal tissue in the treatment of neurodegenerative disorders, while promising, faces several difficult technical and ethical issues. An alternative approach that would obviate these problems would be to use immortalized cell lines of human fetal central nervous system origin. An immortalized human fetal astrocyte cell line (SVG) has been established (45) and herein we describe the in vitro and in vivo characteristics of this cell line which suggest that it may be a useful vehicle for neural transplantation. The SVG cell line is vimentin, GFAP, Thy 1.1 and MHC class I positive, and negative for neurofilament and neuron specific enolase, consistent with its glial origin. To determine whether the cell line could be used as a drug delivery system, a cDNA expression vector for tyrosine hydroxylase was constructed (phTH/Neo) and stably expressed in the SVG cells for over 18 months as demonstrated by immunohistochemistry and Western blotting of the stable transfectants. HPLC analysis of the supernatant from these cells, termed SVG-TH, consistently found 4-6 pmol/ml/min of l-dopa produced with the addition of BH4 to the media. Furthermore, in cocultivation experiments with hNT neurons, PC-12 cells and primary rat fetal mesencephalic tissue, both the SVG and SVG-TH cells demonstrated neurotrophic potential, suggesting that they constituitively express factors with neuroregenerative potential. To determine the viability of these cells in vivo, SVG-TH cells were grafted into the striatum of Sprague-Dawley rats and followed over time. A panel of antibodies was used to unequivocally differentiate the engrafted cells from the host parenchyma, including antibodies to: SV40 large T antigen (expressed in the SVG-TH cells), human and rat MHC class 1, vimentin, GFAP, and tyrosine hydroxylase. While the graft was easily identified with the first week, over the course of a four week period of time the engrafted cells decreased in number. Concomittantly, rat CD4 and CD8 expression in the vicinity of the graft increased, consistent with xenograft rejection. When the SVG-TH cells were grafted to the lesioned striatum of a 6-hydroxydopamine lesioned rats, rotational behavior of the rat decreased as much as 80% initially, then slowly returned to baseline over the next four weeks, parallelling graft rejection. Thus, the SVG-TH cells can induce a functional recovery in an animal model of Parkinson's disease, however as a xenograft, the SVG cells are recognized by the immune system.

Expression of Tyrosine Hydroxylase in an Immortalized Human Fetal Astrocyte Cell Line; in Vitro Characterization and Engraftment into the Rodent Striatum

The use of primary human fetal tissue in the treatment of neurodegenerative disorders, while promising, faces several difficult technical and ethical issues. An alternative approach that would obviate these problems would be to use immortalized cell lines of human fetal central nervous system origin. An immortalized human fetal astrocyte cell line (SVG) has been established (45) and herein we describe the in vitro and in vivo characteristics of this cell line which suggest that it may be a useful vehicle for neural transplantation. The SVG cell line is vimentin, GFAP, Thy 1.1 and MHC class I positive, and negative for neurofilament and neuron specific enolase, consistent with its glial origin. To determine whether the cell line could be used as a drug delivery system, a cDNA expression vector for tyrosine hydroxylase was constructed (phTH/Neo) and stably expressed in the SVG cells for over 18 months as demonstrated by immunohistochemistry and Western blotting of the stable transfectants. HPLC analysis of the supernatant from these cells, termed SVG-TH, consistently found 4-6 pmol/ml/min of 1-dopa produced with the addition of BH4to the media. Furthermore, in cocultivation experiments with hNT neurons, PC-12 cells and primary rat fetal mesencephalic tissue, both the SVG and SVG-TH cells demonstrated neurotrophic potential, suggesting that they constituitively express factors with neuroregenerative potential. To determine the viability of these cells in vivo, SVG-TH cells were grafted into the striatum of Sprague-Dawley rats and followed over time. A panel of antibodies was used to unequivocally differentiate the engrafted cells from the host parenchyma, including antibodies to: SV40 large T antigen (expressed in the SVG-TH cells), human and rat MHC class 1, vimentin, GFAP, and tyrosine hydroxylase. While the graft was easily identified with the first week, over the course of a four week period of time the engrafted cells decreased in number. Concomittantly, rat CD4 and CD8 expression in the vicinity of the graft increased, consistent with xenograft rejection. When the SVG-TH cells were grafted to the lesioned striatum of a 6-hydroxydopamine lesioned rats, rotational behavior of the rat decreased as much as 80% initially, then slowly returned to baseline over the next four weeks, parallelling graft rejection. Thus, the SVG-TH cells can induce a functional recovery in an animal model of Parkinson's disease, however as a xenograft, the SVG cells are recognized by the immune system.

Effects of hypothermia on traumatic brain injury in immature rats

Hypothermia is beneficial in adult models of traumatic brain injury (TBI), but it has not been evaluated in an immature animal model. We hypothesized that brief hypothermia applied after TBI would reduce cerebral edema and lesion volume in immature rats. Male Wistar rats (3-4 weeks of age, 90-140 g) were anesthetized, intubated, mechanically ventilated, and subjected to TBI by weight drop onto the exposed right parietal cortex. Hypothermic rats were then cooled to a brain temperature of 32.0 +/- 0.5 degrees C for 4 h, and control rats were maintained at a brain temperature of 37.0 +/- 0.5 degrees C. Cerebral edema (wet - dry weight method) was assessed at 5 days. At 4 h, a reduction of percent brain water in the traumatized hemisphere was observed in hypothermic versus normothermic rats (81.75 +/- 0.60 vs. 82.53 +/- 0.67%; p<0.05), but by 24 h posttrauma, the groups were similar (p = 0.82). Total lesion volume (47.2 +/- 8.5 vs. 44.4 +/- 10.0 mm3; p = 0.51) and necrotic volume (20.2 +/- 6.3 vs. 20.0 +/- 7.9 mm3; p = 0.95) were similar in the hypothermic and normothermic groups. We conclude that in this model, a transient (4-h) application of moderate (32 degrees C) hypothermia reduces the cerebral edema characteristically seen in immature rats at 4 h, but this reduction is not sustained at 24 h. Attenuating or delaying the development of cerebral edema could have important therapeutic relevance after TBI. Transient hypothermia, however, did not reduce lesion volume at 5 days posttrauma.

A novel function for apolipoprotein B: lipoprotein synthesis in the yolk sac is critical for maternal-fetal lipid transport in mice

Apolipoprotein (apo) B, the principal structural component necessary for the synthesis and secretion of triglyceride-rich lipoproteins by the intestine and liver, is highly expressed in the yolk sac visceral endoderm of mammals, although its function in this tissue has been hitherto unclear. Disruption of the apoB gene in mice results in embryonic lethality (approximately 9.5 - 10.5 d). Here we demonstrate that apoB is normally expressed at early time points in embryonic development in yolk sac visceral endodermal cells, and that this expression is associated with the synthesis and secretion of apoB-containing lipoproteins. The lack of apoB in the visceral endoderm resulted in an accumulation of intracellular lipid droplets, an absence of lipoproteins from the secretory pathway, and reduced concentrations of cholesterol and alpha-tocopherol in tissues of apoB-/- embryos. Visceral endoderm of apoB+/- embryos exhibited an intermediate phenotype. Our results suggest that apoB plays an essential role in the transport of lipid nutrients to the developing mouse embryo via the yolk sac-mediated synthesis and secretion of apoB-containing lipoproteins.

A unique case of long-term survival in a male patient with malignant melanoma of the distal urethra

Primary malignant melanoma of the urethra in male patients is a rare entity, noted to have a dismal prognosis in recent reviews. No case of long-term disease-free survival in patients with primary malignant melanoma has been previously reported. We report the first such case, and review briefly the factors that could have contributed to our patient's long-term survival. We also illustrate the precursor lesion present six years prior to diagnosis.

A comparison of four patient immobilization devices in the treatment of prostate cancer patients with three dimensional conformal radiotherapy

PURPOSE

To determine the variability of patient positioning during three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer treated with no immobilization or one of four immunobilization devices, and to determine the effects of patient body habitus and pelvic circumference on patient movement with each individual inmobilization technique.

METHODS AND MATERIALS

To see whether our immobilization techniques have improved day-to-day patient movement, a retrospective analysis was carried out. A total of 62 patients treated at one facility on a single machine with 3D-CRT via a four-field box technique (anterior-posterior and opposed laterals) in the supine position with either no immobilization or one of four immobilization devices. Five groups of patients were compared: (a) group 1-no immobilization; (b) group 2-alpha cradle from the waist to upper thigh; (c) group 3-alpha cradle from waist to below the knees; (d) group 4-styrofoam leg immobilizer (below knees); and (e) group 5-aquaplast cast encompassing the entire abdomen and pelvis to midthigh with alpha cradle immobilization to their lower legs and feet. Prior to starting radiotherapy, portal films of all four treatment fields were obtained 1 day before treatment. Subsequently, portal films were then obtained at least once a week. Portal films were compared with the simulation films and appropriate changes were made and verified on the next day prior to treatment. A deviation of greater than 0.5 cm or greater was considered to be clincally significant in our analysis. We studied the difference among the types of immobilization and no immobilization by looking at the frequency of movements (overall, and on each of the three axes) that a patient had during the course of his treatment. Using a logistic regression model, the probability of overall and individual directional movement for each group was obtained. In addition, the effects of patient body habitus and pelvic circumference on movement were analyzed.

RESULTS

The maximum deviation was 2 cm and the median deviation was 1.2 cm. For each patient, the probability of movement ranged from 0 to 76%, with a mean of 39%. There was no significant difference seen in overall movement with any of the immobilzation devices compared to no immobilization, but there was less vertical (9 vs. 18%; p = 0.03) and AP (6 vs. 15%; p = 0.14) movement with the aquaplast than any other group. However, when examining the lateral direction, the aquaplast had significantly more movement (32 vs. 9%; p < 0.001). When accounting for body habitus and pelvic circumference, no immobilization device was effective in reducing movement in obese patients or in patients with pelvic circumference greater than 105 cm. The aquaplast group had a significantly increased amount of lateral movement with obesity (42 vs. 23%; p < 0.05), and with pelvic circumference >105 cm (33 vs. 29%; p < 0.05).

CONCLUSIONS

There was no significant reduction in overall patient movement noted with any of the immobilization devices compared to no immobilization. The aquaplast group had reduced vertical and AP movement of greater than 0.5 cm. There was significantly more lateral movement with aquaplast appreciated in obese patients or patients with pelvic circumferences greater than 105 cm. The aquaplast immobilization appears to be useful in reducing movement in two very clinicaly important dimensions (AP and vertical). Despite our findings, other immobilization may still be useful especially in the treatment of nonobese patients. It is clear that the optimal immobilization technique and patient positioning are yet to be determined.

A genetic model for absent chylomicron formation: mice producing apolipoprotein B in the liver, but not in the intestine

The formation of chylomicrons by the intestine is important for the absorption of dietary fats and fat-soluble vitamins (e.g., retinol, alpha-tocopherol). Apo B plays an essential structural role in the formation of chylomicrons in the intestine as well as the VLDL in the liver. We have developed genetically modified mice that express apo B in the liver but not in the intestine. By electron microscopy, the enterocytes of these mice lacked nascent chylomicrons in the endoplasmic reticulum and Golgi apparatus. Because these mice could not form chylomicrons, the intestinal villus enterocytes were massively engorged with fat, which was contained in cytosolic lipid droplets. These mice absorbed D-xylose normally, but there was virtually no absorption of retinol palmitate or cholesterol. The levels of alpha-tocopherol in the plasma were extremely low. Of note, the absence of chylomicron synthesis in the intestine did not appear to have a significant effect on the plasma levels of the apo B-containing lipoproteins produced by the liver. The mice lacking intestinal apo B expression represent the first genetic model of defective absorption of fats and fat-soluble vitamins and provide a useful animal model for studying nutrition and lipoprotein metabolism.