Regulation of encephalitogenic T cells with recombinant TCR ligands

We have previously described recombinant MHC class II beta1 and alpha1 domains loaded with free antigenic peptides with potent inhibitory activity on encephalitogenic T cells. We have now produced single-chain constructs in which the peptide Ag is genetically encoded within the same exon as the linked beta1 and alpha1 domains, overcoming the problem of displacement of peptide Ag from the peptide binding cleft. We here describe clinical effects of recombinant TCR ligands (RTLs) comprised of the rat RT1.B beta1alpha1 domains covalently linked to the 72-89 peptide of guinea pig myelin basic protein (RTL-201), to the corresponding 72-89 peptide from rat myelin basic protein (RTL-200), or to cardiac myosin peptide CM-2 (RTL-203). Only RTL-201 possessed the ability to prevent and treat active or passive experimental autoimmune encephalomyelitis. Amelioration of experimental autoimmune encephalomyelitis was associated with a selective inhibition of proliferation response and cytokine production by Ag-stimulated lymph node T cells and a drastic reduction in the number of encephalitogenic and recruited inflammatory cells infiltrating the CNS. The exquisitely selective inhibition could be observed between molecules that differ by a single methyl group (the single amino acid residue difference between RTL-200 (threonine) and RTL-201 (serine) at position 80 of the myelin basic protein peptide). These novel RTLs provide a platform for developing potent and selective human diagnostic and therapeutic agents for treatment of autoimmune disease.

Induction of Th1 response by dendritic cells pulsed with autologous melanoma apoptotic bodies

BACKGROUND

We hypothesize that dendritic cells (DCs) can process antigens from autologous melanoma apoptotic bodies (MABs) and induce effector T cells in melanoma patients.

MATERIALS AND METHODS

Peripheral blood mononuclear cells were obtained from three stage IV melanoma patients and adherent cells were cultured in complete medium (CM) containing GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 7 days. Autologous MABs from melanoma cells following actinomycin D treatment (0.5 microgram/ml) for 24 hours, were added to 72 hour DC culture. Autologous effector T cells were cultured in CM containing 60 IU/ml of IL-2 and were stimulated by MAB-pulsed DCs three times at a weekly interval. Effector T cells were harvested at the end of third cycle of DC stimulation.

RESULTS

Using ELISPOT, IFN-gamma production by effector T cells stimulated by MAB-pulsed DCs was significantly higher than that by T cells without DC stimulation. Microscopy demonstrated phagocytosis of MABs by DCs.

CONCLUSIONS

MAB-pulsed DCs are capable of stimulating Th1-directed autologous effector T cells. Pulsing DCs with autologous MABs may be a novel approach in future DC-based immunotherapeutic trials.

Correlation of genetic instability with mismatch repair protein expression and p53 mutations in non-small cell lung cancer

To examine the etiological association of genetic instability in lung tumorigenesis, we investigated the frequency of microsatellite instability (MI) of eight dinucleotide repeat markers in 68 patients with non-small cell lung cancer. Twenty-eight patients (41.2%) evidenced instability in multiple tested microsatellite markers ranging from 3-7 and were defined as MI-positive patients. MI occurred more frequently in patients suffering from squamous cell lung carcinoma (P = 0.004). We examined the association between MI and expression of hMLH1 mismatch repair protein by immunohistochemical analysis of hMLH1 protein in paraffin-embedded tumors from 64 patients. Twenty MI-positive patients (76.9%) had no expression of hMLH1 protein. The data showed that MI was associated with altered hMLH1 expression (P = 0.03). To examine the role of genetic instability in the previous identified small intragenic deletion of the p53 gene, we explored the association between MI and p53 gene mutations. All patients, except one, containing small intragenic deletion in p53 gene showed MI (P = 0.018). In addition, we found that MI was not associated with the prognosis. Our data suggest that MI plays a significant role in non-small cell lung cancer tumorigenesis in Taiwan and that MI is associated with the altered expression of hMLH1 mismatch repair protein. In addition, MI may be involved in frequent small intragenic deletions of p53 gene.

Adenovirus-mediated p14(ARF) gene transfer in human mesothelioma cells

BACKGROUND

The p14(ARF) protein encoded by the INK4a/ARF locus promotes degradation of the MDM2 protein and thus prevents the MDM2-mediated inhibition of p53. Homozygous deletion of the INK4a/ARF locus is common in human mesothelioma and may result in the loss of p14(ARF) and the inactivation of p53. We designed this study to evaluate the biologic and potential therapeutic roles of p14(ARF) expression in mesothelioma cells.

METHODS AND RESULTS

We constructed Adp14, an adenoviral vector carrying human p14(ARF) complementary DNA, and used it to transfect human mesothelioma cell lines H28, H513, H2052, and MSTO-211H. Overexpression of p14(ARF) led to increased amounts of p53 and the p21(WAF) proteins and dephosphorylation of the retinoblastoma protein. The growth rate of mesothelioma cells was inhibited markedly by infection with Adp14 compared with mock infection or infection with a control adenovirus vector, AdCtrl. Overexpression of p14(ARF) induced G(1)-phase cell cycle arrest and apoptotic cell death. Cytotoxicity assays showed that Adp14 had a statistically significantly (P =.002) greater effect on colon cancer (HCT116) cell lines containing two copies of the wild-type p53 gene than on p53-null cells, suggesting that functional p53 is a critical determinant of p14(ARF)-mediated cytotoxicity.

CONCLUSIONS

The transfection of p14(ARF) into mesothelioma cells led to the overexpression of p14(ARF), which resulted in G(1)-phase arrest and apoptotic cell death. These results suggest that this gene therapy-based approach may be of use in the treatment of mesothelioma.

Gamma Knife radiosurgery for functioning pituitary adenomas

Stereotactic radiosurgery has been an important treatment modality in the treatment of pituitary adenomas. However, it has the disadvantage of a delayed effect on hormonal normalization compared with microsurgical resection of functioning pituitary adenomas. To define the efficacy of radiosurgery in the treatment of functioning pituitary adenomas, 37 cases with a mean follow-up duration of 26.9 months were analyzed. There were 18 prolactinomas, 11 cases with acromegaly, and 8 cases with Cushing s disease. The mean maximum dose was 54.8 Gy. The tumor margin was encompassed within the 50 to 90% isodose. The level of serum prolactin, growth hormone, and 24-hour urine free cortisol were evaluated for hormonal follow-up according to the relevant endocrinopathy. There was 35.1% hormonal normalization and an 81.8% decline in hormone levels to below 50% of the preoperative value (hormonal response). Hormonal normalization was obtained in 13 patients (mean latency = 22 months). A hormonal response was seen in 30 patients (mean latency = 7.6 months). The maximum dose and tumor volume included in the prescription isodose were significantly correlated with the latency period from radiosurgery to hormonal normalization. These results suggest that early hormonal normalization can best be achieved by a high maximum dose (at least 55 Gy) and broad coverage of the target tumor volume within the prescription dose thereby increasing the integral dose.

The effects of stereotactic radiosurgery on secondary facial pain

Twenty-seven patients with tumor-related secondary facial pain were treated by stereotactic radiosurgical procedures between November 1991 and October 1998. They had 14 meningiomas, 11 schwannomas (one trigeminal, 10 vestibular), one nasopharyngeal cancer and one chordoma. The mean maximum dose administered was 26.4 Gy (range 16 to 35 Gy) and the margin of the tumor was encompassed within the 45 to 90% isodose. The patients were analyzed based on their pain relief with a mean follow-up duration of 32.1 months. In 24 patients (85.7%), there was initial pain improvement after radiosurgery, but half had recurrent pain. A pain response was obtained in 12 cases (pain response rate = 42.9%), five were pain free and seven had pain reduction. On the follow-up MRI, a decrease in tumor volume of more than 20% of the preoperative volume occurred in 14 of 25 cases. The mean time interval to initial pain improvement (10.3 months) and pain response (5.7 months) were shorter than for a decrease in tumor volume (18.6 months). Tumor-related secondary facial pain was less responsive to stereotactic radiosurgery than idiopathic trigeminal neuralgia. It would seem that the mechanism of pain relief in radiosurgery is not only trigeminal root decompression secondary to tumor volume reduction, but also other mechanisms involving inactivation of abnormal electrical transmission may be involved.

[Effect of ascorbic acid on chemiluminescence of cells cultivated in various concentration of oxygen]

OBJECTIVE

To investigate the effect of Vitamin C (Vit. C) on the stimulated chemiluminescence of rabbit's pulmonary alveolus macrophage (AM) cultivated in various concentration of oxygen.

METHOD

The AMs from rabbits were cultured in a thermostat in which luminescence from cells can be examined, then air with various concentrations of oxygen were continuously led in the device and the AM's stimulated chemiluminescence by PMA (phorbol myristate acetate) was measured with a chemiluminometer.

RESULT

In the air with 0.5% O2, AM's survival rate and luminescence level were only 50% or 45% of the values before the exposure, and were reducing progressively with increasing dose of Vit. C in the culture medium. To increase the concentration of oxygen in the air was advantageous in enhancing cell's vitality and it can partly counteract the decrease of AM's stimulated chemiluminescence level by adding Vit. C into the culture medium.

CONCLUSION

Oxygen in the air is important for cultivated cell's luminescence and survival, and it could lead to grave damage to the cultivated AMs when there is high concentration of Vit. C in the culture medium.

Role of calcium/calmodulin-dependent protein kinases in expression of Fos protein in the nucleus tractus solitarii after sustained hypertension

We investigated the role of calcium/calmodulin-dependent protein kinases in the phosphorylation of cyclic AMP response element binding protein and subsequent induction of c-fos gene elicited by sustained hypertension in neurons of the nucleus tractus solitarii of anesthetized rats. Activation of glutamate receptors in the nucleus tractus solitarii significantly increased the number of neurons that were immunoreactive to phosphorylated cyclic AMP response element binding protein and Fos protein. Microinjection bilaterally into the nucleus tractus solitarii of the calcium/calmodulin-dependent protein kinase inhibitor, 1-[N,O-bis(5-isoquinolinesulfonyl-N-methyl-L-tyrosyl]-4-phenylpiperazine , appreciably blunted such an increase. This inhibitor also attenuated the augmented immunoreactivity for phosphorylated cyclic AMP response element binding protein or Fos protein in the same nucleus induced by sustained hypertension. These results were comparable to those observed after blockade of either N-methyl-D-aspartate or non-N-methyl-D-aspartate ionotropic glutamate receptors in the nucleus tractus solitarii. Reverse transcription-polymerase chain reaction further indicated that the calcium/calmodulin-dependent protein kinase blocker attenuated the expression of Fos protein induced by sustained hypertension in the nucleus tractus solitarii by suppressing the transcription of c-fos messenger RNA. The present results suggest that activation of calcium/calmodulin-dependent protein kinases may represent an important step in the cascade of intracellular events that leads to phosphorylation of cyclic AMP response element binding protein and subsequent induction of c-fos gene after activation of ionotropic glutamate receptors by baroceptive signals in the nucleus tractus solitarii.

Design, engineering and production of functional single-chain T cell receptor ligands

Major histocompatibility complex (MHC) class II molecules are membrane-anchored heterodimers on the surface of antigen presenting cells (APCs) that bind the T cell receptor, initiating a cascade of interactions that results in antigen-specific activation of clonal populations of T cells. The peptide binding/T cell recognition domains of rat MHC class II (alpha-1 and beta-1 domains) were expressed as a single exon for structural and functional characterization. These recombinant single-chain T cell receptor ligands (termed 'beta1alpha1' molecules) of approximately 200 amino acid residues were designed using the structural backbone of MHC class II molecules as template, and have been produced in Escherichia coli with and without N-terminal extensions containing antigenic peptides. Structural characterization using circular dichroism predicted that these molecules retained the antiparallel beta-sheet platform and antiparallel alpha-helices observed in the native MHC class II heterodimer. The proteins exhibited a cooperative two-state thermal folding-unfolding transition. Beta1alpha1 molecules with a covalently linked MBP-72-89 peptide showed increased stability to thermal unfolding relative to the empty beta1alpha1 molecules. This new class of small soluble polypeptide provides a template for designing and refining human homologues useful in detecting and regulating pathogenic T cells.

Characterization of dendritic cells generated from peripheral blood of patients with malignant melanoma

Dendritic cells (DCs) are professional antigen presenting cells. Two x 10(7) peripheral blood mononuclear cells (PBMCs) from each of 6 melanoma patients and 4 normal donors were incubated in 6-well plates. The adherent cells were cultured in GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 10 days. Anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-class I monoclonal antibodies and supernatant from two melanoma cell lines were incubated with DCs before responder T cells were added in mixed lymphocyte reaction (MLR). The mean yields of DCs were 3.6 x 10(5) and 9.3 x 10(5) for donor and the melanoma patients respectively. MLR was inhibited by anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-Class I and supernatant of melanoma cultures. The characteristics of DCs generated from melanoma patients were comparable to those from donors. DC function was inhibited by soluble factors in melanoma cultures. Further studies are warranted to characterize these inhibitory factors.

Vesicular monoamine transporter-2 and aromatic L-amino acid decarboxylase enhance dopamine delivery after L-3, 4-dihydroxyphenylalanine administration in Parkinsonian rats

Medical therapy in Parkinson's disease (PD) is limited by the short-duration response and development of dyskinesia that result from chronic L-3,4-dihydroxyphenylalanine (L-DOPA) therapy. These problems occur partly because the loss of dopamine storage sites leads to erratic dopamine delivery. Vesicular monoamine transporter-2 (VMAT-2) plays a critical role in dopamine storage by packaging dopamine into synaptic vesicles and regulating sustained release of dopamine. To restore the capacity to produce and store dopamine in parkinsonian rats, primary skin fibroblast cells (PF) were genetically modified with aromatic L-amino acid decarboxylase (AADC) and VMAT-2 genes. After incubation with L-DOPA in culture, the doubly transduced fibroblast cells (PFVMAA) produced and stored dopamine at a much higher level than the cells with either gene alone. PFVMAA cells in culture released dopamine gradually in a constitutive manner. Genetically modified fibroblast cells were grafted in parkinsonian rat striata, and L-DOPA was systemically administered. Higher dopamine levels were sustained for a longer duration in rats grafted with PFVMAA cells than in those grafted with either control cells or cells with AADC alone. These findings underscore the importance of dopamine storage capacity in determining the efficacy of L-DOPA therapy and illustrate a novel method of gene therapy combined with precursor administration to overcome the major obstacles of PD treatment.

Biochemical and anatomical characterization of forepaw adjusting steps in rat models of Parkinson's disease: studies on medial forebrain bundle and striatal lesions

Deficits in forepaw adjusting steps in rats have been proposed as a non-drug-induced model of the akinesia associated with Parkinson's disease. The present study examined the relationship between contralateral forepaw adjusting steps and dopamine depletion after medial forebrain bundle lesions with 6-hydroxydopamine. Depletion of striatal dopamine by >80% resulted in dramatic reductions in the ability of rats to make adjusting steps, but rats with < 80% dopamine depletion had no detectable deficit. The deficit in forepaw adjusting steps was evident by three days after lesions and did not recover for up to 13 weeks. Compared to apomorphine-induced rotation, the deficit in adjusting steps was evident at milder dopamine depletion. Discrete striatal lesions were also utilized to localize the striatal subregions that mediate forepaw adjusting steps. Forepaw adjusting steps were reduced after lesions of dorsolateral, ventrolateral or ventrocentral striatum, but not after lesions of dorsomedial, dorsocentral or ventromedial striatum. The reductions in adjusting steps after the discrete striatal lesions were not as severe as after medial forebrain bundle lesions. Furthermore, none of the discrete striatal lesions resulted in rotation after apomorphine administration, although a few resulted in increase in amphetamine-induced rotation. Administration of L-3,4-dihydroxyphenylalanine partially reversed the reductions of forepaw adjusting steps in both sets of lesion experiments. Together, these results suggest that forepaw adjusting step deficits in the rat provide a good model for the akinesia of Parkinson's disease both in medial forebrain bundle and striatal lesions, and would be a useful tool for investigating the efficacy of various therapeutic strategies.

Catastrophic progression of the disassembly of a modular acetabular component

Disassembly of a metal-backed modular acetabular component used for total hip arthroplasty is becoming more common. If the acetabular disassembly is detected early, the revision procedures are relatively simple. In the case of long-term sustained disassembly, however, there are more complicated problems, and more difficult revision procedures are needed. We report a case of long-term sustained disassembly of a modular acetabular component in order to alert orthopaedic surgeons of the catastrophic progression to more severe complications, such as the loosening of the metal-acetabular component and severe acetabular osteolysis.

Microbial invasion of the amniotic cavity with Ureaplasma urealyticum is associated with a robust host response in fetal, amniotic, and maternal compartments

OBJECTIVE

Ureaplasma urealyticum is the microorganism most frequently isolated from the amniotic fluid of women with preterm labor and preterm premature rupture of the membranes, yet the significance of amniotic fluid infection exclusively caused by this microorganism is unclear. This study was conducted to examine the presence and intensity of the inflammatory response in the fetal, amniotic, and maternal compartments in patients with preterm premature rupture of membranes and amniotic fluid infection with U urealyticum.

STUDY DESIGN

One hundred twenty patients with preterm premature rupture of the membranes who delivered preterm neonates (gestational age </=36 weeks) within 5 days of amniocentesis were included. Amniotic fluid was cultured for aerobic and anaerobic bacterias and mycoplasmas. The intensity of the inflammatory response was evaluated by amniotic fluid concentrations of interleukin-6, tumor necrosis factor-alpha, interleukin-1beta, amniotic fluid white blood cell count, histologic chorioamnionitis, and interleukin-6 concentrations of umbilical cord plasma at birth. Cytokines were measured by sensitive and specific immunoassays.

RESULTS

The prevalence of a positive amniotic fluid culture in which the only microbial isolate was U urealyticum was 21% (25/120) and that of positive cultures with other or mixed microorganisms was 9% (11/120). Intrauterine inflammatory response was significantly more intense in patients with positive amniotic fluid cultures limited to U urealyticum than in those with a negative culture (median and range of amniotic fluid interleukin-6, 13.4 [0.7-115.2] ng/mL vs 0.9 [0.001-137.2] ng/mL; median and range of amniotic fluid tumor necrosis factor-alpha, 85.5 [0.9-1600] pg/mL vs 2.4 [0-1142] pg/mL; median and range of amniotic fluid interleukin-1beta, 274.0 [0.3->80,000] pg/mL vs 3.4 [0-1449] pg/mL; median and range of amniotic fluid white blood cell count, 306 [0-19,764] cells/mm3 vs 3 [0-7956] cells/mm3; median and range of cord interleukin-6, 20.0 [2. 3-1199.6] pg/mL vs 6.7 [0-5550] pg/mL; histologic chorioamnionitis, 100% [22/22] vs 42% [30/72]; P <.01 for each) but was similar to values of patients with a positive amniotic fluid culture for other bacteria or mixed microorganisms.

CONCLUSION

Patients with preterm premature rupture of membranes and microbial invasion of the amniotic cavity with U urealyticum are associated with a robust host inflammatory response in the fetal, amniotic, and maternal compartments.

Digital quantification of the enzyme-linked immunospot (ELISPOT)

Enzyme-linked immunospot (ELISPOT) is a sensitive technique for the detection of cytokines released by immune cells. The technique is well established and correlates closely with the enzyme-linked immunosorbent assay (ELISA) technique. Here, we introduce an integrated imaging-analysis system to quantitate the spots formed by the ELISPOT assay. The spots can be easily counted when the background is clear and the spots are few. However, when the number of spots increases to > 100, this task becomes challenging and time-consuming. To minimize time and standardize the counting procedure, we have used a digital camera linked to a computer system for reading the plates. In general, the computer is able to count more spots and has a smaller standard deviation when compared with the manual microscopic count. This integrated system is commercially available, and we believe that this method is objective, time-saving and consistent in routine ELISPOT assay counting, especially when numerous spots are present.

Microvascular decompression and percutaneous rhizotomy in trigeminal neuralgia

We analyzed 417 patients with trigeminal neuralgia who underwent microvascular decompression (MVD; n = 146) or percutaneous procedures, i.e. radiofrequency rhizotomy (RFR; n = 235) and glycerol rhizotomy (GR; n = 36) between March 1973 and December 1996. MVD and RFR showed the highest rates of initial pain relief (MVD 96.5%; RFR 92.3%; GR 82.8%). RFR and GR had 5.1 and 3.3% rates of facial dysesthesia, respectively, and MVD had the lowest rate (0.3%). Among 9 cases (8.6%) with recurrences after MVD, 8 cases underwent RFR and all of them obtained good long-term results (7.2 years on average). We concluded that MVD is the treatment of choice for tolerant younger patients and should be recommended for patients who desire no sensory deficit. We also determined that radiofrequency rhizotomy is the procedure of choice for patients in whom MVD failed.

Isolation of Ureaplasma urealyticum from the amniotic cavity and adverse outcome in preterm labor

OBJECTIVE

To determine the relationship between the presence of Ureaplasma urealyticum in the amniotic cavity and adverse maternal and perinatal outcome in women with preterm labor.

METHODS

Amniocentesis was performed in 181 patients with preterm labor and intact membranes. Amniotic fluid (AF) was cultured for aerobic and anaerobic bacteria and mycoplasmas. Patients were divided into three groups according to the results of AF culture: those with negative AF cultures (n=160), those with positive AF cultures and in whom the only microbial isolate was U urealyticum (n=11), and those with positive cultures for non-ureaplasmas or mixed microorganisms (n=10). Survival techniques were used for analysis.

RESULTS

The prevalence of positive AF cultures in which the only microbial isolate was Uurealyticum was 6.1% (11 of 181), and of positive cultures with non-ureaplasmas or mixed microorganisms was 5.5% (10 of 181). The amniocentesis-to-delivery interval was significantly shorter in patients with positive cultures limited to U urealyticum than in those with negative cultures (median 7 [range 0.1-149] hours versus median 264 [0.1-2659] hours, P < .001). Preterm delivery within 48 hours, 72 hours, and 7 days was more frequent in patients with U urealyticum in the AF than in those with sterile AF (48 hour: 91% versus 33%; 72 hour: 91% versus 36%; 7 days: 100% versus 45%, P < .001 for each). Patients with positive AF cultures limited to U urealyticum had a significantly higher rate of adverse perinatal outcome than those with negative culture. Adverse outcomes included low gestational age at birth, low birth weight, histologic chorioamnionitis, significant neonatal morbidity, and perinatal death.

CONCLUSION

Microbial invasion of the amniotic cavity with U urealyticum is a risk factor for impending preterm delivery and adverse perinatal outcome.

Regulation of renin secretion through reversible phosphorylation of myosin by myosin light chain kinase and protein phosphatase type 1

Possible involvement of reversible phosphorylation and dephosphorylation of myosin light chain (MLC) by myosin light chain kinase (MLCK) and protein phosphatases (PPases), respectively, in the Ca++-calmodulin-dependent inhibition of renin secretion was investigated with the use of putative MLCK inhibitor ML-7 [1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine] and PPase type1 (PPase-1) and type 2A (PPase-2A) inhibitor calyculin A. ML-7 (1 x 10(-)6 to 3 x 10(-)5 M) increased renin secretion in vitro from rat renal cortical slices under "resting" conditions in a concentration-dependent manner with maximal 2.5-fold stimulation. Furthermore, Ca++-induced inhibition of renin secretion in depolarizing K+-rich Krebs-Ringer bicarbonate not only was prevented completely but also reversed by ML-7 in a concentration-dependent and reversible manner. On the other hand, calyculin A (3 x 10(-)6 M) blocked both effects of ML-7 on stimulation and reversal of renin secretion independently of intracellular Ca++ concentrations. Such antagonistic effects of ML-7 and calyculin A on renin secretion most likely resulted from their respective effects on the level of MLC phosphorylation: ML-7 stimulates renin secretion by decreasing phosphorylation of MLC through its inhibition of MLCK, whereas calyculin A inhibits secretion by increasing phosphorylation of MLC through its inhibition of PPase-1. By inference from these results, MLC may be the target protein involved in regulation of the renin secretory process by Ca++: Ca++-calmodulin phosphorylates MLC via activating MLCK and thereby inhibits renin secretion, whereas dephosphorylation of phosphorylated MLC by PPase-1 reverses the inhibited secretion. We therefore conclude that reversible phosphorylation of MLC may be an important biochemical step determining the rate of renin secretion from the juxtaglomerular cell.

Volume changes following gamma knife radiosurgery of intracranial tumors

BACKGROUND

The primary goal of radiosurgery for brain tumors is the prevention of further growth. The purpose of this article is to evaluate temporal changes of tumor volume after Gamma Knife radiosurgery on intracranial tumors.

METHOD

Some 137 patients with 148 intracranial tumors who were treated with Gamma Knife radiosurgery and underwent radiological follow-up were reviewed. The tumors with high radiosensitivities to conventional external radiation were excluded.

RESULT

The median radiological follow-up period was 12 months (range 1.5-38 months). Volume decreased after radiosurgery in 15 of 45 meningiomas; 10 of 37 schwannomas; 6 of 21 pituitary adenomas; 4 of 15 benign gliomas, including both of 2 subependymal giant cell astrocytomas; and 2 of 8 malignant gliomas. Some 87% of meningiomas and 60% of schwannomas whose volume had decreased began to shrink within 12 months and after 12 months, respectively. Transitory increase in volume preceded shrinkage in 16.2% of schwannomas, 13.3% of benign gliomas, 4.8% of pituitary adenomas, and 2.2% of meningiomas. Marked shrinkage occurred in 17 of 19 metastatic tumors and in all 3 neurocytomas shortly after radiosurgery. Of eight malignant gliomas, five began to grow 2-14 months (median = 5 months) after radiosurgery.

CONCLUSION

Several points should be considered carefully while following up on patients after radiosurgery: the possibility of transient volume increase, tumor-specific volume change patterns, and the tumor-specific goals of radiosurgery.

Dendritic translocation of RC3/neurogranin mRNA in normal aging, Alzheimer disease and fronto-temporal dementia

RC3/neurogranin is a postsynaptic protein kinase C (PKC)-/calmodulin-binding substrate implicated in long-term potentiation (LTP) forms of synaptic plasticity. Our previous digoxigenin in situ hybridization (DIG-ISH) studies detected RC3 mRNA in apical dendrites and cell bodies of neurons in the rat cerebral cortex and hippocampus. This observation suggested that RC3 mRNA is selectively translocated to dendrites, where it may be translated locally in response to synaptic activity. To test this hypothesis further, we isolated a full-length cDNA clone of the homologous human RC3 mRNA from a human cortex lambda GT11 library, determined its nucleotide and predicted amino acid sequences, and performed mRNA expression studies in cerebral cortex from normal human patients and from patients with Alzheimer disease (AD) and fronto-temporal dementia (FTD). The human cDNA clone detects a single approximately 1.3 kb mRNA whose nucleotide sequence is 73% similar to the rat nucleotide sequence and 96% similar to its amino acid sequence. DIG-ISH studies detect robust staining of RC3 mRNA in cell bodies of numerous neurons throughout Layers II-VI and in both apical and basal dendrites of pyramidal neurons in human neocortex (temporal/frontal). We conclude that dendritic targeting of RC3 mRNA is conserved in human brain. In AD neocortex tissue, there is little or no evidence for RC3 mRNA translocation to dendrites, while in FTD neocortex, targeting of RC3 mRNA to apical dendrites is preserved. Comparative studies in AD and FTD point to the potential importance of synapse integrity and the dendritic cytoskeleton in RC3 mRNA targeting in the human neocortex.

Prostaglandin G/H synthase-2 (cyclooxygenase-2) mRNA expression is decreased in Alzheimer's disease

Recent evidence suggests that the use of nonsteroidal anti-inflammatory drugs (NSAIDS) is beneficial for therapy or prevention of Alzheimer's disease (AD). The major anti-inflammatory action of NSAIDS is to inhibit prostaglandin G/H synthase-2 (PGHS-2), the first committed enzymatic step for prostaglandin biosynthesis. We have previously shown that PGHS-2 message is induced by Interleukin-1 beta and other inflammatory mediators in primary cultures of rodent astrocytes. To determine whether similar elevations of PGHS-2 occur as part of the gliosis in AD, we quantified PGHS-2 mRNA levels in control and AD brain by Northern hybridization analysis. To our surprise we found that PGHS-2 mRNA levels were reduced threefold in AD neocortex relative to control brain tissue. In contrast, levels were not reduced in putamen, an area that is relatively spared in AD. To localize PGHS-2 mRNA production in control and AD brain, sections of neocortex and hippocampus were hybridized with a 35S-labeled riboprobe for human PGHS-2 followed by immunocytochemistry with antibodies against neuron specific enolase (NSE) or glial fibrillary acidic protein (GFAP). Our findings indicate that PGHS-2 message is primarily localized to cells that stain for NSE rather than GFAP. Furthermore, in the three cases we examined, PGHS-2 hybridization per neuron appeared to be reduced in AD. Thus, the decrease we observe in overall PGSH-2 mRNA levels is likely to reflect both the known decline in numbers of neurons in AD as well as a lowered capacity for neuronal synthesis of PGHS-2, perhaps due to dysfunction or a loss of synaptic input.

Inhibition of renin secretion by Ca2+ through activation of myosin light chain kinase

This study sought to identify specific enzyme(s) involved in the biochemical cascade of inhibition of renin secretion through Ca(2+)-calmodulin mediation with the use of inhibitors of protein kinase and phosphatases. Inhibition of renin secretion mediated by Ca(2+)-calmodulin was induced by incubating rat renal cortical slices in K(+)-rich depolarizing medium, producing > 50% inhibition. This inhibition was completely blocked by the calmodulin antagonist calmidazolium. The inhibitor of protein kinase with broad specificity, K-252a, blocked the inhibition of renin secretion. Neither KN-62, a specific inhibitor of Ca(2+)-calmodulin-dependent protein kinase II (CaMK II), nor specific inhibitors of protein phosphatase 2B (PP2B), cyclosporin A and FK-506, blocked the inhibition. On the other hand, all four known inhibitors specific for myosin light chain kinase (MLCK), with different chemical structures and mechanisms of inhibition (ML-9, ML-7, KT-5926 and wortmannin), almost completely protected renin secretion against the inhibition by Ca2+. In particular, ML-9 reversively protected > 77% secretion against the inhibition both in K(+)-rich medium alone and in combination with the calcium ionophore A-23187 in a concentration-dependent manner. Together, these findings from our present study provide the first evidence, albeit indirect in nature, for the possibility that activation of Ca(2+)-calmodulin-dependent MLCK at the downstream of Ca2+ influx into juxtaglomerular (JG) cells leads to phosphorylation of 20-kDa regulatory myosin light chain (MLC20). Through interaction with actin, the phosphorylated MLC20 may play an important role in the inhibitory stimulus-secretion coupling of renin.

Interleukin-1 beta induces prostaglandin G/H synthase-2 (cyclooxygenase-2) in primary murine astrocyte cultures

Activation of glial cells and the consequent release of cytokines, proteins, and other intercellular signaling molecules is a well-recognized phenomenon in brain injury and neurodegenerative disease. We and others have previously described an inducible prostaglandin G/H synthase, known as PGHS-2 or cyclooxygenase-2, that is up-regulated in many cell systems by cytokines and growth factors and down-regulated by glucocorticoid hormones. In cultured mouse astrocytes we observed increased production of prostaglandin E2 (PGE2) after stimulation with either interleukin-1 beta (IL-1 beta) or the protein kinase C activator phorbol 12-myristate 13-acetate (TPA). This increase in PGE2 content was blocked by pretreatment with dexamethasone and correlated with increases in cyclooxygenase activity measured at 4 h. Northern blots revealed concomitant increases in PGHS-2 mRNA levels that peaked at 2 h and were dependent on the dosage of IL-1 beta. Dexamethasone inhibited this induction of PGHS-2 mRNA by IL-1 beta. TPA, basic fibroblast growth factor, and the proinflammatory factors tumor necrosis factor alpha and lipopolysaccharide, but not interleukin-6, also stimulated PGHS-2 mRNA expression. Relative to IL-1 beta, the greater increases in PGE2 production and cyclooxygenase activity caused by TPA correlated with a greater induction of PGHS-2 mRNA. Furthermore NS-398, a specific inhibitor of cyclooxygenase-2, blocked > 80% of the cyclooxygenase activity in TPA-treated astrocytes. These findings indicate that increased expression of PGHS-2 contributes to prostaglandin production in cultured astrocytes exposed to cytokines and other factors.