Depletion of blood-borne macrophages does not reduce demyelination in mice infected with a neurotropic coronavirus

Mice infected with the neurotropic coronavirus mouse hepatitis virus strain JHM (MHV-JHM) develop a chronic demyelinating disease with symptoms of hindlimb paralysis. Histological examination of the brains and spinal cords of these animals reveals the presence of large numbers of activated macrophages/microglia. In two other experimental models of demyelination, experimental allergic encephalomyelitis and Theiler's murine encephalomyelitis virus-induced demyelination, depletion of hematogenous macrophages abrogates the demyelinating process. In both of these diseases, early events in the demyelinating process are inhibited by macrophage depletion. From these studies, it was not possible to determine whether infiltrating macrophages were required for late steps in the process, such as myelin removal. In this study, we show that when macrophages are depleted with either unmodified or mannosylated liposomes encapsulating dichloromethylene diphosphate, the amount of demyelination detected in MHV-infected mice is not affected. At a time when these cells were completely depleted from the liver, approximately equivalent numbers of macrophages were present in the spinal cords of control and drug-treated animals. These results suggest that blood-borne macrophages are not required for MHV-induced demyelination and also suggest that other cells, such as perivascular macrophages or microglia, perform the function of these cells in the presence of drug.

[Effects of castor oil-diet on the synthesis of prostaglandin E2 in pregnant rats]

OBJECTIVE

To determine effects of castor oil-diet on the synthesis of prostaglandin E2(PGE2) and explore the mechanism of labor induced by castor oil-diet in pregnant rats.

METHODS

Pregnant rats were gavaged castor oil-diet in 18 and 19 days of gestation. At the time of death, blood of portal and peripheral veins, intestinal mucosa, amnion, amniotic cells and placenta were collected, and the tissues were cultured in the presence of ricinoleic acid or indomethacin. The concentrations of PGE2 in the media or blood were measured by RIA methods.

RESULTS

The PGE2 levels in the portal vein increased, while the PGE2 levels in peripheral blood had no changes significantly, the PGE2 levels in the tissues of the intestinal mucosa, placenta, amnion and amniotic cells were increased significantly; Ricinoleic acid stimulated the synthesis of PGE2 in the above tissues in vitro, which had the positive correlations with the dose of ricinoleic acid and its lasting time. Indomethacin inhibited the synthesis of PGE2 in-vitro.

CONCLUSION

The increased synthesis of PGE2 in the intrauterine tissues is a key of the initiation of labor induced by castor oil-diet, and ricinoleic acid in castor oil-diet might be the active component which induced the initiator of labor.

[The diagnostic value of high field MRI for choroidal melanoma]

OBJECTIVE

To clarify the characteristic magnetic resonance imaging (MRI) features of choroidal melanomas by the high field MRI to improve the accuracy of diagnosis and localization and to differentiate choroidal melanomas from other choroidal lesions.

METHODS

12 patients with choroidal melanomas were examined by GE 1.5T magnet and heat coil, fat suppression technique and GD-DPTA as contrast agent were also used. Ten patients underwent operations and the histopathologic diagnosis was confirmed.

RESULTS

The melanomas of the 12 patients had relatively high signals on T(1) weighted image and relatively low signals on T(2) weighted image. This is because of the paramagnetic properties of melanin. The melanomas with melanin can produce stable free radicals, both T(1) and T(2) relaxation times are shortened, with this we can differentiate melanomas from other choroidal lesions.

CONCLUSION

Sagittal, coronal, axial and oblique scanning with small feild of view for the orbit by MRI can be made to show the exact position of melanomas and differentiate them from other choroidal lesions.

[A study of correlation between essential hypertension and HLA-DQA1 alleles]

OBJECTIVE

To analyse the hereditary susceptibility by genotyping of HLA-DQA1 alleles in essential hypertensives.

METHODS

The allelic types of HLA-DQA1 were detected by PCR-SSP technic in 52 cases of essential hypertensives and 86 normal individuals as the control.

RESULTS

The frequency of HLA-DQA1*0302 allele in hypertensive group was markedly higher than that in normal control group (17.9572 vs 3.5531), but the frequency of HLA-DQA1*0103 allele in normal group was higher than that in hypertensive group.

CONCLUSION

HLA-DQA1*0302 may be a correlative gene of essential hypertension, whereas HLA-DQA1*0103 may be a defence gene of hypertension.

[Effect of castor oil-diet on the initiation of labor of pregnant rat]

OBJECTIVE

This study was designed to explor the effect of castor oil-diet, on the intiation of labor of preganant rat and determine what the active component of castor oil-diet was.

METHODS

The time of the intiation of labor and course of delivery were observed by gavaged rats castor oil-diet at 18, 19 and 20 days of gestation. The compositions of fat acid of castor oil-diet and castor oil were analyzed by HPLC.

RESULTS

The castor oil-diet could induce the initiation of labor and shorte the course of the delivery in pregnant rats. Ricinoleic acid was the active component of castor oil-diet in this study.

CONCLUSIONS

Pregnant rats by gavaged castor oil-diet could serve as the animal model for induction of labor. Ricinoleic acid is likely the chief component to the induction of labor.

Immunohistochemical localization of tissue plasminogen activator in vascular endothelium of stroke-prone regions of the rat brain

OBJECTIVE

Tissue plasminogen activator (tPA), a major regulator of fibrinolysis, is present in cerebrovascular endothelium. We have suggested that local regulation of tPA synthesis and release in brain microcirculation could be important determinants of the degree of damage after cerebral ischemia. In this study, the normal distribution of tPA antigen was determined in several stroke-prone regions in the rat brain often used to study the pathophysiological consequences of cerebral ischemia.

METHODS

Immunohistochemistry and Western blot analysis were performed using an antibody that detects free tPA antigen and tPA complexed to its rapid inhibitor, plasminogen activator inhibitor-1 (PAI-1). Staining for von Willebrand factor, a brain endothelial cell marker, served as a positive control.

RESULTS

Relative to von Willebrand factor, 8.6, 13, 11.4, and 20.4% of vessels in the parietal cortex, frontal cortex, striatum, and hippocampus, respectively, were tPA-positive. The majority of tPA-positive vessels (58-75%) were classified as precapillary arterioles and postcapillary venules (7-20 microm), whereas capillaries (4-7 microm) and small arterioles and venules (20-40 microm) accounted for 11 to 22% and 11 to 19%, respectively, of tPA-positive vessels. Western blot analysis of brain microvascular proteins confirmed the presence of free tPA (67 kDa) and a stronger band representing tPA-PAI-1 complexes.

CONCLUSION

The tPA-containing cerebrovascular endothelium is distributed mainly in smaller vessels. In addition to the free pool of tPA, a large portion of tPA is complexed to PAI-1 and is therefore functionally inactive. The size of the free tPA cerebrovascular pool may be regulated by PAI-1, which in turn could suppress fibrinolysis in the cerebral microcirculation.

Immunohistochemical localization of redox factor-1 (Ref-1) in Alzheimer's hippocampus

Redox factor-1 (Ref-1) is a dual-function protein involved in both DNA repair and transcriptional regulation. Ref-1 is modulated by cerebral ischemia and other oxidative stressors, and also regulates the DNA-binding activities of transcription factors implicated in Alzheimer's disease (AD)-related neurodegeneration. The present study examined Ref-1 expression in the AD hippocampus by immunohistochemistry. Although Ref-1 immunostaining was relatively low in control brain sections, senile plaques and other plaque-like structures in the AD brain were Ref-1-positive. Cells with increased Ref-1 immunoreactivity were also observed in regions of neuronal injury. These results suggest that Ref-1 might contribute to senile plaque formation, and that overexpression of Ref-1 in injured neurons may be part of a response to oxidative stress and an attempt to repair damaged DNA in AD.

[Antenatal diagnosis of albinism fetuses by fetalscopy]

OBJECTIVE

To popularize the clinical utility of fetalscopy in antenatal diagnosis of albinism fetuses.

METHODS

Fetalscopy examination was carried out in 85 high-risk pregnancy women, during 17 to 26 gestational weeks. Guided by the ultrasonography, the fetalscopy was inserted into the aminotic sac. Albinism fetuses was diagnosed by the color of the fetal hair.

RESULTS

Fetalscopy were succeed in 79 of 85 high-risk women (93%). 63 fetuses were diagnosed as normal, 16 fetuses was diagnosed of albinism. There were 2 false-positive cases at 17 weeks of gestation due to mistaking wooly hair for hair.

CONCLUSION

Fetalscopy is a quick, accurate, safe method in antenatal diagnosis of heredity diseases, such as albinism.

[Early postoperative intraperitoneal perfusion chemotherapy for advanced colorectal cancer]

OBJECTIVE

To study the effect of early postoperative intraperitoneal perfusion chemotherapy (IPPC) on the prevention of peritoneal recurrence and liver metastasis in patients with advanced colorectal cancer.

METHODS

From 1990 through 1997, 102 patients with advanced colorectal cancer were admitted. The tumor invaded the intestinal serosa with elevated CEA in the peritoneal fluid. Fifty-four of the 102 patients, beginning from the operation day, were given IPPC, once per day for 6 days, with warm(43-45 degrees C) sterile double distilled water containing 1 g 5-Fu and 10 mg MMC. The other 48 patients, as control, received 1 g 5-Fu and 8 mg MMC by i.v. infusion, once per day for 6 days. In addition, oral tegafur was given to all patients with a total dose of 40 g.

RESULTS

In patients treated with IPPC, peritoneal recurrence developed in 2 patients, liver metastasis in 2 patients whereas 12 cases had peritoneal recurrence and 6 had liver metastasis in patients treated by i.v. infusion. No complication developed in any of the treated patients.

CONCLUSION

IPPC is effective in preventing tumor recurrence in the peritoneal cavity and metastasis to the liver in patients with advanced colorectal cancer. The treatment procedure is simple and safe.

Mutational analysis of histidine residues in the rabbit Na+/dicarboxylate co-transporter NaDC-1

Succinate transport by the rabbit Na+/dicarboxylate co-transporter, NaDC-1, expressed in Xenopus oocytes was inhibited by the histidyl-selective reagent diethyl pyrocarbonate (DEPC). Therefore the role of histidine residues in the function of NaDC-1 was examined by site-directed mutagenesis. All 11 histidine residues in NaDC-1 were converted to alanine, but only mutant H106A exhibited a decrease in succinate transport. Additional mutations of NaDC-1 at position 106 showed that aspartic acid and asparagine, but not arginine, can substitute for histidine. Examination of succinate and citrate kinetics of H106A revealed a decrease in Vmax with no change in Km. Cell surface biotinylation experiments showed that the transport activity of all four mutants at position 106 was correlated with the amount of cell surface expression, suggesting a role of His-106 in membrane expression rather than function. Two of the histidine mutants, H153A and H569A, exhibited insensitivity to inhibition by DEPC, indicating that these residues are involved in binding DEPC. Neither of these residues is required for transport activity; thus DEPC probably inhibits NaDC-1 function by hindrance of the mobility of the carrier. We conclude that histidine residues are not critical for transport function in NaDC-1, although His-106 might be involved in determining protein expression or stability in the membrane.

The substrate recognition domain in the Na+/dicarboxylate and Na+/sulfate cotransporters is located in the carboxy-terminal portion of the protein

The Na+/dicarboxylate cotransporter, NaDC-1, and the Na+/sulfate cotransporter, NaSi-1, share 43% sequence identity, but they exhibit no overlap in substrate specificity. A functional chimera, SiDC-4, was prepared from NaDC-1 and NaSi-1 by homologous recombination and expressed in Xenopus oocytes. SiDC-4 contains putative transmembrane domains 1-4 of NaSi-1 (amino acids 1-139) and putative transmembrane domains 5-11 of NaDC-1 (amino acids 141-593). SiDC-4 retains the substrate specificity of NaDC-1, which suggests that the substrate recognition domain is found in the carboxy-terminal portion of the protein, past amino acid 141. However, residues that affect substrate affinity and inhibition by furosemide and flufenamate are found in the amino terminal third of the protein. The cation binding properties of SiDC-4, including a stimulation of transport by lithium, differed from both parental transporters, suggesting that cation binding is determined by interactions between the amino- and carboxy-terminal portions of the protein. We conclude that the substrate recognition site of NaDC-1 and NaSi-1 is found in the carboxy-terminal portion of the protein, past amino acid 141, but residues in the amino terminus can affect substrate affinity, inhibitor sensitivity, and cation selectivity.

[Early diagnosis of nasopharyngeal carcinoma using recombinant antigens expressed in bacteria]

An enzyme-linked immunosorbent assay(ELISA) was developed by using recombinant purified early antigens, EA-D and EA-R to detect IgA antibodies in sera from nasopharyngeal carcinoma(NPC) patients. 30 sera from NPC patients and 49 sera from normal persons were detected by the developed ELISA. The serum positive rate and antibody titer were compared with immunoenzymatic method(IE) on slide with Raji cells mears. ELISA is more sensitive and specific. The serum positive rate of NPC patients was increased from 70% by IE to 100% by ELISA and 77% of the serum antibody titer reached > or = 1:200. The results show that the expressed recombinant p138 and p54 antigens are effective for detection of EA/IgA antibody in sera from NPC patients and ELISA will be a sensitive, specific and convenient method for early diagnosis of NPC.

[The transfection and morphological changes of human embryonic nasopharyngeal epithelia infected by Epstein-Barr virus cooperated with promoter in vitro and in vivo]

In order to detect the ability of EBV on transfecting and transforming human nasopharyngeal epithelia(HNE) isolated from human embryo, the HNE was cultured in vitro and then transplanted into nude mice. HNEs were treated by EBV, EBV + TPA and TPA in vitro, respectively. The mice transplanted with HNE tissues were injected subdermally by EBV, EBV + TPA and distilled water several times, respectively. The morphological changes indicated that EBV induced not only enhancement of foci and N/C ratio in cultured HNE which are important characteristics of malignant transformation, but also carcinogenesis of transplanted HNE, all of the carcinoma were EBV positive. TPA seems to increase EBV transfection rate (EBV PCR positive rate) in vitro, especially in the early stage. TPA alone did not exert effect on malignant transformation Cooperating with TPA, EBV induced early invasive carcinoma in vivo.

[Rapid prenatal diagnosis of Down's syndrome in the first trimester of pregnancy by fluorescence in situ hybridization]

OBJECTIVE

To assess whether fluorescence in situ hybridization (FISH) with chromosome 21, specific DNA probe is applicable as a prenatal diagnostic tool for Down's syndrome.

METHOD

We used FISH with chromosome 21 specific probe on 30 uncultured chorionic villi cell samples to detect the Down's fetus, and we also performed the conventional chromosome analysis of chorion cells from parallel samples.

RESULTS

In samples with disomic karyotype, an average of 1 percent (0-5 percent) of the nuclei had three hybridization signals. By contrast, in the samples of trisomy 21 fetus, an average of 86 percent (78-91 percent) of the nuclei displayed three signals.

CONCLUSION

FISH can provide a rapid and accurate method for the first trimester prenatal diagnosis of Down's syndrome.

Residues essential for catalysis and stability of the active site of Escherichia coli adenylosuccinate synthetase as revealed by directed mutation and kinetics

Examined here by directed mutation, circular dichroism spectroscopy, and kinetics are the relationships of five residues, Asp13, Glu14, Lys16, His41, and Arg131, to the catalytic function and structural organization of adenylosuccinate synthetase from Escherichia coli. The D13A mutant has no measurable activity. Mutants E14A and H41N exhibit 1% of the activity of the wild-type enzyme and 2-7-fold increases in the Km of substrates. The mutant K16Q has 34% of the activity of wild-type enzyme and Km values for substrates virtually unchanged from those of the wild-type system. Mutation of Arg131 to leucine caused only a 4-fold increase in the Km for aspartate relative to the wild-type enzyme. The dramatic effects of the D13A, E14A, and H41N mutations on kcat are consistent with the putative roles assigned to Asp13 (catalytic base), His41 (catalytic acid), and Glu14 (structural organization of the active site). The modest effect of the R131L mutation on the binding of aspartate is also in harmony with recent crystallographic investigations, which suggests that Arg131 stabilizes the conformation of the loop that binds the beta-carboxylate of aspartate. The modest effect of the K16Q mutation, however, contrasts with significant changes brought about by the mutation of the corresponding lysines in the P-loop of other GTP- and ATP-binding proteins. Crystallographic structures place Lys16 in a position of direct interaction with the gamma-phosphate of GTP. Furthermore, lysine is present at corresponding positions in all known sequences of adenylosuccinate synthetase. We suggest that along with a modest role in stabilizing the transition state of the phosphotransfer reaction, Lys16 may stabilize the enzyme structurally. In addition, the modest loss of catalytic activity of the K16Q mutant may confer such a selective disadvantage to E. coli that this seemingly innocuous mutation is not tolerated in nature.

Isolation of the gene encoding lamp-1, a lysosomal membrane protein, by differential screening in an animal model of status epilepticus

The present study employed differential library screening to identify genes associated with kainic acid (KA)-mediated selective neuronal death. One of the isolated clones was lamp-1, which encodes a major lysosomal membrane protein that is also present in the cell membrane. Following systemic KA treatment, lamp-1 was induced in vulnerable hippocampal and other limbic regions. This effect was blocked by cycloheximide (CHX) pre-treatment. Northern blot analysis also demonstrated the presence of lamp-1 transcripts in non-neural tissues. These findings suggest a novel role for lysosomal membrane proteins as markers of selective neuronal vulnerability.

Induction of tumor suppressor p53 and DNA fragmentation in organotypic hippocampal cultures following excitotoxin treatment

The p53 tumor suppressor gene encodes a cell cycle regulatory protein that is induced by DNA damage and has been implicated in apoptosis. To investigate whether excitotoxic cell death due to kainic acid (KA) and cell death due to N-methyl-D-aspartate (NMDA) share similar molecular mechanisms, we studied p53 expression and DNA fragmentation in organotypic hippocampal slice cultures following excitotoxin treatment. Cellular analyses showed that both p53 induction and DNA fragmentation occurred only in injured neurons following exposure to either excitotoxin. The temporal profiles of these changes demonstrated that p53 induction preceded DNA fragmentation. The extent of regional alterations in p53 expression and DNA fragmentation correlated with drug-related toxicity (i.e., NMDA > KA). These results support the hypothesis that p53 is a marker of neuronal death in the CNS and suggest the possibility that excitotoxin-mediated neuronal death may occur through a p53-dependent pathway.

Chronic nicotine treatment enhances focal ischemic brain injury and depletes free pool of brain microvascular tissue plasminogen activator in rats

Effects of nicotine treatment (4.5 mg/kg of nicotine-free base/day administered s.c. by osmotic minipumps for 14 days) on focal ischemic stroke and expression of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) in cerebral microvessels were studied in rats in vivo using a reversible (1 h) middle cerebral artery occlusion model. Plasma levels of nicotine and its major metabolite cotinine after 14 days of treatment were 88 and 364 ng/ml, respectively. Nicotine treatment resulted in 35-40% (p < 0.001) decrease in the blood flow in the periphery of the ischemic core during reperfusion, an increase in the neurologic score of 2.6-fold (p < 0.01), and 36% (p < 0.05) and 121% (p < 0.01) increases in the injury and edema volume in the pallium, respectively. A free pool of brain microvascular t-PA antigen was completely depleted by nicotine, while the expression of the PAI-1 antigen and/or PAI-1-t-PA complexes remained unchanged. The relative abundance of cerebromicrovascular t-PA mRNA transcript versus beta-actin mRNA transcript did not change with nicotine. It is concluded that chronic nicotine treatment impairs the restoration of blood flow, worsens the neurologic outcome, and enhances brain injury following an ischemic insult. These nicotine effects are associated with depletion of brain microvascular t-PA antigen.

Characterization of the rabbit renal Na(+)-dicarboxylate cotransporter using antifusion protein antibodies

Polyclonal antibodies were prepared against the rabbit renal Na(+)-dicarboxylate cotransporter, NaDC-1. The antibodies were raised in chickens against a fusion protein consisting of a 60-amino acid peptide from NaDC-1 and glutathione S-transferase. These antibodies specifically recognized the fusion protein in Western blots and could immunoprecipitate the full-length NaDC-1 after in vitro translation. The antifusion protein antibodies specifically recognized a protein of 63 kDa in rabbit renal brush-border membrane vesicles (BBMV), similar to the predicted mass of 66 kDa. Two proteins of 57 and 115 kDa were recognized in rabbit intestinal brush-border membranes. A protein of 66 kDa was recognized in Xenopus oocytes injected with NaDC-1 cRNA. Enzymatic deglycosylation of rabbit renal BBMV resulted in a decrease in mass by 11 kDa, consistent with N-glycosylation at a single site. Site-directed mutagenesis of the two consensus sequences for N-glycosylation in the NaDC-1 cDNA showed that Asn-576, located near the COOH-terminal, is glycosylated. The nonglycosylated mutant of NaDC-1 exhibited 50% of wild-type succinate transport activity when expressed in Xenopus oocytes, suggesting that glycosylation is not essential for function. The revised secondary structure model of NaDC-1 contains 11 putative transmembrane domains and an extracellular glycosylated COOH-terminal.

Functional differences between rabbit and human Na(+)-dicarboxylate cotransporters, NaDC-1 and hNaDC-1

The rabbit and human Na(+)-dicarboxylate cotransporters, NaDC-1 and hNaDC-1, were expressed in Xenopus oocytes, and the transport of succinate, citrate, and glutarate was compared. Both transporters had similar affinities for succinate and glutarate, with Michaelis-Menten constant (K(m)) values of approximately 0.5- 0.8 mM (succinate) and 6-7 mM (glutarate), verifying that they are low-affinity sodium-dependent dicarboxylate transporters. The two transporters differed in their handling of citrate. At pH 7.5, the K(m) value for citrate was 0.9 mM in the rabbit NaDC-1 and 7 mM in the human hNaDC-1. However, the human transporter was more sensitive to pH than the rabbit. At pH 5.5, the K(m) value for citrate decreased to 1.2 mM in hNaDC-1 and decreased to 0.3 mM in the rabbit transporter. Both transporters had Hill coefficients between 1.6 and 2.1, suggesting that multiple sodium ions are coupled to the transport of divalent anions. However, the human transporter, hNaDC-1, had a lower apparent affinity for sodium (KNa, 78 mM) than the rabbit transporter (KNa, 41 mM). In addition, the human hNaDC-1 was relatively insensitive to inhibition by lithium, furosemide, and flufenamate compared with the rabbit NaDC-1. The differences between the human and rabbit transporters may account for observed differences in renal handling of citrate between species.

Anterograde, transneuronal transport of herpes simplex virus type 1 strain H129 in the murine visual system

Herpes simplex virus (HSV) undergoes retrograde and anterograde axonal transport as it establishes latency and later intermittently reactivates. Most strains of HSV show preferential retrograde transport within the central nervous system (CNS), however. Previous experiments suggest that an exception to this is HSV type 1 (HSV-1) strain H129, since this virus appears to spread primarily in the CNS via anterograde, transneuronal movement. The objective of the present study was to test how specifically this virus spreads in the visual system, a system with well-described neuronal connections. In the present study, the pattern of viral spread was examined following inoculation into the murine vitreous body. Virus was initially detected in the retina and optic tract. Virus then appeared in all known primary targets of the retina, including those in the thalamus (e.g., lateral geniculate complex), hypothalamus (suprachiasmatic nucleus), and superior colliculus (superficial layers). In previous studies, many strains of HSV were shown to infect these structures, even though they spread predominantly in a retrograde direction. However, the H129 strain was unique in then spreading, via anterograde transport, to the primary visual cortex (layer 4 of area 17) via thalamocortical connections. At later times after infection, specific labeling was also detected in other cortical and subcortical areas known to receive projections from the visual cortex. No labeling was ever detected in the contralateral retina, which is consistent with a lack of retrograde spread of HSV-1 strain H129. These results demonstrate the specific anterograde movement of this virus from the retina to subcortical and cortical regions, with no clear evidence for retrograde spread. HSV-1 strain H129 should be generally useful for tracing sensory pathways and may provide the basis for designing a virus vector capable of delivering genetic material via anterograde pathways within the CNS.

Antenatal diagnosis and management of Dandy-Walker syndrome

The Dandy-Walker syndrome (DWS) can be accurately diagnosed in utero by sonographic demonstration of characteristic morphologic changes of the fetus, which includes hydrocephalus, incomplete cerebellar vermis and a posterior fossa cyst. We present a case of Dandy-Walker syndrome diagnosed antenatally. The associated anomalies are reviewed, and the value of antenatal diagnosis is discussed.

Brain capillary tissue plasminogen activator in a diabetes stroke model

BACKGROUND AND PURPOSE

Tissue plasminogen activator (TPA) is normally expressed in rat brain capillaries. This study examines the expression of TPA in brain capillaries of diabetic rats in relation to focal ischemic brain injury.

METHODS

Diabetes type 1 was induced by streptozotocin for 7 days. Acute hyperglycemia was induced by 50% dextrose. Expression of TPA in brain capillaries was determined by Western blot and reverse transcription-polymerase chain reaction analyses. Focal stroke was produced by 1 hour of reversible middle cerebral artery occlusion. Physiological variables and cerebral blood flow were monitored during occlusion and within 1 hour of reperfusion. Neurological and neuropathologic examinations were performed after 24 hours of reperfusion.

RESULTS

All rats developed comparable hyperglycemia (approximately 15 mmol/L). A complete depletion of TPA protein and 6.5-fold decrease in TPA mRNA were found in brain capillaries of diabetic rats, in contrast to normal TPA capillary levels in hyperglycemic rats. The blood flow in the periphery of the ischemic core was significantly reduced during reperfusion by 52% to 62% (P<.001) in diabetic rats and by 23% to 25% (P<.05) in hyperglycemic rats. The neurological score was worsened by 3.2-fold (P<.0003) by diabetes and by 24% by hyperglycemia only. Significant 41% (P<.007) and 29% (P<.05) increases in infarct volume and 163% (P<.007) and 60% increases in edema volume were found in diabetic rats relative to control and hyperglycemic rats, respectively.

CONCLUSIONS

Diabetes type 1, but not acute hyperglycemia, produces downregulation of TPA in rat brain capillaries. This TPA reduction is associated with impaired restoration of blood flow after an ischemic insult, poor neurological outcome, and enhanced ischemic brain injury.

Cordocentesis: a useful method for prenatal diagnosis

OBJECTIVE

To evaluate the efficacy and safety of cordocentesis for prenatal diagnosis of various fetal diseases.

PATIENTS AND METHODS

Fetal blood sampling was performed in 30 pregnancies from gestational week 19 to 36 for various prenatal diagnoses. We used Aloka SSD-650 real-time ultrasound scanner with 3.5 mHz curvilinear transducer during the procedure. A regular 22-gauge spinal needle was used for fetal blood sampling.

RESULTS

Twenty-five cordocentesis were successful at the first attempt. A second attempt of cordocentesis succeeded in three cases. In the remaining two cases, intrahepatic vein sampling and cardiocentesis were employed respectively. The duration of procedure was shorter than 15 minutes in 25 cases. 1-6 ml of fetal blood was obtained from each case. Fetal blood was diluted with amniotic fluid in four samples. Maternal blood contamination never happened. No lethal complication occurred in our series.

CONCLUSION

It is believed that cordocentesis is a safe and useful method for prenatal diagnosis, and intrahepatic vein sampling is an alternative choice when cordocentesis has failed.

[Cordocentesis for prenatal diagnosis of fetal diseases]

For the purpose of prenatal diagnosis, 30 fetal blood samplings were performed in 30 pregnant women from 19 to 36 gestational weeks. The samples were taken with a 22-gauge needle guided by ultrasound. Twenty-five cordocenteses were succeeded at the first attempt. A second attempt was needed in other 5 cases. The duration of procedure was less than 15 minutes in 83.3% cases. 1-6 ml fetal blood was obtained for each case. No lethal complication occured in our series. It is believed that cordocentesis could be a useful tool for prenatal diagnosis, and the intrahepatic-vein sampling is a preferable alternative choice if cordocentesis fails.

Nuclear accumulation of p53 protein following kainic acid-induced seizures

The p53 tumor suppressor gene has been implicated in apoptotic cell death. The present study was conducted to investigate whether expression of p53 protein is increased in association with kainic acid-induced neuronal apoptosis. Adult male Sprague-Dawley rats were treated systemically with the glutamate analog kainic acid, and sacrificed either 4 or 30 h after the onset of seizure activity. Immunohistochemistry was performed on paraffin-embedded sections using an anti-p53 polyclonal antibody. At both time points, increased p53 immuno-reactivity was observed predominantly in the nucleus of apoptotic neurons. These findings lend additional support to the hypothesis that p53 is a marker of neuronal apoptosis in the CNS, and suggest that nuclear accumulation of p53 protein may be an important mediator of neuronal death.

Activation of astrocytes in the spinal cord of mice chronically infected with a neurotropic coronavirus

Mice infected with the neurotropic JHM strain of mouse hepatitis virus (MHV-JHM) develop a demyelinating encephalomyelitis several weeks after infection. Astrogliosis and infiltration of inflammatory cells are prominent findings in the brains and spinal cords of infected mice. In this report, astrocytes in infected spinal cords were analyzed for expression of three pleiotropic cytokines, TNF-alpha, IL-1 beta, and IL-6; Type 2 nitric oxide synthase (iNOS); and MHC class I and II antigen. The data show that all three cytokines and iNOS are expressed by astrocytes in chronically infected spinal cords. These activated astrocytes are localized to areas of virus infection and demyelination, although most of the astrocytes expressing these proteins are not MHV-infected. MHC class I and II antigen can be detected in these spinal cords as well, but not in cells with the typical morphology of astrocytes. TNF-alpha, IL-6, and iNOS are also evident in the brains of mice with MHV-induced acute encephalitis, but in marked contrast to the results obtained with the chronically infected mice, most of the cells expressing these cytokines or iNOS had the morphology of macrophages or other mononuclear cells and very few appeared to be astrocytes. Additionally, astrocytes and, most likely, oligodendrocytes are infected in the spinal cords of mice with chronic demyelination. These results are consistent with a role for both viral infection of glial cells and high localized levels of proinflammatory cytokines and nitric oxide in the demyelinating process in mice infected with MHV-JHM. They also show that analogously to the human demyelinating disease, multiple sclerosis, astrocytes are a major cellular source for these cytokines in mice with chronic, but not acute disease.

Expression of tissue plasminogen activator in cerebral capillaries: possible fibrinolytic function of the blood-brain barrier

Previous work has shown that tissue plasminogen activator (tPA) is a key enzyme in the control of fibrinolysis within the vascular system. The sources of brain tPA and the mechanisms by which tPA secretion and production occur within cerebral microcirculation are not well established. In this study, expression of tPA was investigated in cerebral capillaries and capillary-depleted brain isolated from cortices of 4- to 5-week-old rats and guinea pigs. In both species, a single tPA band of M(r) 67,000 was detected in cerebral capillaries by Western blot analysis. The tPA signal was absent from capillary-depleted brain. These results were corroborated at the messenger ribonucleic acid level. Reverse transcription-polymerase chain reaction analysis revealed the presence of tPA complementary deoxyribonucleic acid in samples derived from cerebral microvessels and demonstrated very low or undetectable tPA expression in capillary-depleted brain. Immunohistochemical analysis confirmed tPA localization in endothelial cells of brain capillaries. We conclude that microvascular endothelium, i.e., the blood-brain barrier, may have a role in promoting plasmin-dependent fibrinolysis in brain microcirculation. Delineation of the molecular mechanisms of blood-brain barrier-mediated fibrinolysis will likely contribute to future stroke prevention efforts.

[Effect of severing trigeminal nerve on intraocular pressure and pupil in rabbits]

Changes of intraocular pressure (IOP) and pupil were observed through severing trigeminal nerve (TN), and the possible effect on TN on regulation of IOP was investigated in 5 rabbits. When TN was severed, the mean IOP at the same side was sharply and significantly elevated, being almost 2-fold of that before the procedure (P < 0.01). After the procedure, the mean elevated IOP decreased rapidly. The mean IOP at the end of the procedure was 0.28kPa higher than that before the procedure, and the IOP difference between pre- and post-procedure was not significant (P > 0.05). There was no significant difference in the comparison between the mean IOP after the procedure for 2 weeks and that before the procedure (P > 0.05). On the other hand, the mean diameter of pupils during and at the end of the procedure was significantly decreased (P < 0.01), when compared with that before the procedure, and afterward it gradually recovered. The above findings show that the rapid and significant reactions of IOP and pupil during the procedure are possibly affected by the actions of some neuropeptides in the TN5 suggesting that TN, participate in the regulation of IOP.

[Rapid detection of numerical aberrations of chromosomes in the first trimester of pregnancy by using fluorescence in situ hybridization (FISH)]

Fluorescence in situ hybridization (FISH) has been applied for rapid prenatal diagnosis of common numerical aberrations of chromosomes. We used FISH with chromosome 13, 18 and 21 specific probes on 528 uncultured mesenchymal chorionic villi cell samples to detect the chromosomal abnormalities, and we also performed the conventional chromosome analysis of cultured cells from parallel samples. The results showed, in samples disomic with respect to the probed chromosomes, and average of 1 percent (range 0-18 percent) had three hybridization signals. By contrast, in the samples trisomic or triploidic for the probed chromosomes, an average of 70 percent (52-84 percent) (chromosome 13), 73 percent (68-84 percent) (chromosome 18), and 76 percent (54-90 percent) (chromosome 21, including one case of mosaic trisomy 21) of the nuclei displayed three signals. The whole test took about 24 hours. We concluded that FISH can provide a rapid and accurate method for the first trimester prenatal idetification of selected numerical aberrations of chromosomes.

Anterograde tracing of trigeminal afferent pathways from the murine tooth pulp to cortex using herpes simplex virus type 1

Due to its predominantly nociceptive innervation, viral tracing from the tooth pulp provides a potential means for tracing central pain pathways. The neural pathways from the tooth pulp to cortex were determined using in situ hybridization to detect the anterograde transneuronal spread of herpes simplex virus type 1 strain H129 following inoculation into the murine mandibular incisor pulp. Virus first appeared in the brain at day 3 in the dorsomedial region of all three subnuclei of the spinal trigeminal nucleus and the principal sensory nucleus. By days 5-6 virus had spread to the contralateral medial nucleus of the medial geniculate complex, posterior thalamus, and ventroposteromedial thalamus. At days 7-8 virus was detected in laminae IV and Va of the primary somatosensory cortex and lamina IV of the secondary somatosensory cortex in regions previously shown to receive input from the lower jaw. Several mice also showed infection of laminae II/III of the ipsilateral dysgranular insular cortex, along with labeling for virus in the ipsilateral external lateral parabrachial nucleus, posterior thalamus, and posterior basolateral amygdala. Our results are highly consistent with previous tracing and electrophysiological studies utilizing the tooth pulp and with studies implicating the infected structures in nociception. Viral spread appeared to define two separate afferent systems with infection of structures which have been implicated in the sensory-discriminative aspects of pain, such as the ventroposteromedial thalamus and somatosensory cortex, as well as in the dysgranular insular cortex and related subcortical nuclei which may have a role in the affective-motivational aspects of pain.

Spread of a neurotropic coronavirus to spinal cord white matter via neurons and astrocytes

Mouse hepatitis virus strain JHM (MHV-JHM) causes a chronic encephalomyelitis in susceptible mice, with histological evidence of demyelination in the spinal cord. After intranasal inoculation, virus spreads retrogradely to several brain structures along neuroanatomic projections to the main olfactory bulb. In the absence of experimental intervention, mice become moribund before the spinal cord is infected. In this study, infusions of anti-MHV neutralizing monoclonal antibodies were administered to protect mice from the MHV-JHM-induced acute encephalitis and to allow survival until virus spread to the spinal cord. Under these conditions, virus was observed to enter specific layers (primarily laminae V to VII) in the gray matter of the upper spinal cord, consistent with transneuronal spread. While the brain structures which are the sources for virus spread to the spinal cord cannot be determined with certainty, the ventral reticular nucleus is likely to be important since it is consistently and extensively labeled in all mice and receives projections from subsequently infected areas of the spinal cord. After initial entry into the gray matter, virus rapidly spread to the white matter of the spinal cord. During the early stages of this process, extensive infection of astrocytes was noted, suggesting that cell-to-cell spread via these glial cells is an important part of this process. Reports from other laboratories using cultured cells strongly suggested that astrocytes serve as important regulators of oligodendrocyte function and, by extrapolation, have a major role in vivo in the processes of both demyelination and remyelination. Thus, our results not only outline the probable pathway used by MHV-JHM to infect the white matter of the spinal cord but also, with the assumption that infection of astrocytes leads to subsequent dysfunction, raise the possibility that infection of these cells contributes to the demyelinating process.

[Chemical compositions of Podocarpus imbricatus]

Twelve components were isolated from Podocar pus imbricatus, of which ten were identified as imbricatafiavone A (1), imbricataflavone B (2), robustaflavone (3), robustaflavone-7"-methyl ether (4), podocarpusflavone A (5), sandaracopimaric acid (6), beta-sitosterol (7), p-hydroxybenzoic acid (8), n-C34H69OH (9) and 10-nonacosanone (10). 4, 5, 8, 9 and 10 are obtained from the species for the first time.

Spread of MHV-JHM from nasal cavity to white matter of spinal cord. Transneuronal movement and involvement of astrocytes

C57B1/6 mice infected intranasally with mouse hepatitis virus, strain JHM (MHV-JHM) develop hindlimb paralysis with histological evidence of demyelination several weeks after inoculation. Virus must spread from the site of inoculation, the nasal cavity, to the site of disease, the white matter of the spinal cord. It has been shown previously that after intranasal inoculation, virus enters the brain via the olfactory nerve and spreads to infect many of its neuroanatomic connections within the central nervous system (CNS). In this report, it is shown that virus infecting the spinal cord is first detected in the gray matter, with spread occurring to the white matter soon thereafter. Astrocytes are heavily infected during the process of spread from the gray to the white matter of the spinal cord. Since astrocytes are in intimate contact with neuronal synapses and are themselves connected via gap junctions, these results suggest that astrocytes may be a conduit for the spread of virus in these mice. Astrocytes provide factors for the proliferation and survival of oligodendrocytes, and widespread infection of these cells might contribute to the demyelinating process eventually observed in these mice. Additionally, since virus first appears at specific locations in the spinal cord, it should be possible to determine the source of the virus infecting the cord. While the results are not definitive, the data are most consistent with virus spreading from the ventral reticular formation to the gray matter of the cervical spinal cord.

Effect of retinoic acid and interferon alpha on granulocyte-macrophage colony forming cells in chronic myeloid leukemia: increased inhibition by all-trans- and 13-cis-retinoic acids in advanced stage disease

Granulocyte-macrophage colony forming units (CFU-GM) from patients with advanced stage chronic myelogenous leukemia (CML), i.e. in blastic crisis (BC) or accelerated phase (AP), were inhibited by all-trans-retinoic acid (tRA) approximately 1000-fold more potently than those from chronic phase (CP) CML patients (median IC50 = 10(-9) M tRA for six CML-AP/BC cases vs > 10(-6) M tRA for seven CML-CP cases). A similar activity pattern was observed for the stereoisomer 13-cis-RA (cRA). There was no apparent correlation of CFU-GM retinoid sensitivity with cloning efficiency or other colony characteristics. Interferon alpha-2a (INF alpha) alone strongly inhibited CFU-GM growth in all four CML-AP/BC cases (IC50 < or = 250 IU/ml) and three out of seven CML-CP cases (IC50 < or = 500 IU/ml), but there was little or no interactive effect between various concentrations of tRA and INF alpha (50 IU/ml) on CFU-GM from either CML-AP/BC or CML-CP cases. These results suggest that CML-AP/BC CFU-GM have some intrinsic molecular alteration(s) which markedly enhances their responsiveness to tRA and cRA, which may be clinically exploitable.

Replacement of Asp333 with Asn by site-directed mutagenesis changes the substrate specificity of Escherichia coli adenylosuccinate synthetase from guanosine 5'-triphosphate to xanthosine 5'-triphosphate

The aspartate residue of the (N/T)KXD concensus sequence for GTP-binding proteins is present in the eight available sequences of adenylosuccinate synthetase. Reported here is a comprehensive analysis of the substrate specificity of mutant enzymes, where the conserved Asp333 of the synthetase from Escherichia coli is changed to asparagine, glutamate, and glutamine by site-directed mutagenesis. The mutants D333N, D333E, and D333Q generally show decreased kcat values and increased Km values for GTP. The decreased values of kcat exhibited by the mutants indicate that the interactions between Asp333 and the guanine are relayed by some mechanism to the catalytic residues around the gamma-phosphate of GTP, and that the energy provided by the interaction between Asp333 and the guanine moiety of GTP is utilized for rearrangement of the catalytic residues. The three mutants each have higher affinity for xanthosine 5'-triphosphate (XTP) and ITP than does the wild-type enzyme. In fact, the D333N mutant uses XTP more effectively than the wild-type enzyme employs GTP as a substrate. The side-chain of Asp333 forms hydrogen bonds with the N-1 and the exocyclic amino group of the guanine base of GTP. In the D333N mutant, this interaction is probably replaced by hydrogen bonds between the amide side chain of Asn333 and N-1 and the 2-oxo group of XTP. The D333Q mutant can use UTP as a substrate more effectively than the wild-type enzyme. The longer side chain of glutamine at residue 333 favors pyrimidine nucleotides over the purine nucleotides, GTP, XTP, and ITP. These results demonstrate that Asp333 in the (N/T)KXD consensus sequence of adenylosuccinate synthetase from E. coli is a determinant for GTP-specificity.

p53 induction is associated with neuronal damage in the central nervous system

The p53 tumor-suppressor gene encodes a growth-regulatory protein that has been implicated in programmed cell death. To investigate the possible role of p53 in neuronal death, we studied p53 expression associated with excitotoxicity in the adult rat brain. Within hours of systemic administration of the glutamate analogue kainic acid, p53 mRNA levels were increased in neurons exhibiting morphological features of damage within kainate-vulnerable brain regions. A similar distribution was found for neurons exhibiting DNA damage as evidenced by in situ end-labeling of fragmented DNA. Pretreatment with the protein synthesis inhibitor cycloheximide prevented both kainate-mediated p53 induction and neuronal damage. The distinctive pattern of excitotoxin-mediated p53 expression suggests that p53 induction is a marker of irreversible injury in postmitotic cells of the central nervous system and could have functional significance in determining selective neuronal vulnerability.

Evidence for a GABAergic interface between cortical afferents and brainstem projection neurons in the rat central extended amygdala

The synaptic circuitry of the intrinsic GABAergic system of the central extended amygdala (CEA) in relation to efferent neurons and cortical afferents was examined in the present study. Neurons in the CEA projecting to the dorsal vagal complex and the parabrachial complex were identified by the retrograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP). Postembedding GABA-immunocytochemistry revealed that GABA-immunoreactive (GABA-IR) terminals formed largely symmetrical synaptic contacts with the perikarya and proximal dendritic processes of almost all WGA-HRP-labeled neurons in the CEA. To determine the relationship between cortical afferents and CEA GABAergic neurons, WGA-HRP was used to anterogradely label afferents from the insular cortex in combination with postembedding immunogold detection of GABA. Cortical afferents formed asymmetrical synaptic contacts predominantly on small dendrites and dendritic spines. Many of the dendrites postsynaptic to cortical terminals in the central nucleus were immunoreactive for GABA although only relatively few spines were GABA-IR. Combining pre-embedding GAD-immunocytochemistry with cortical lesions resulted in approximately 40% of degenerating terminals of insular cortical origin in the central nucleus in contact with small, GAD-IR dendrites and spines. The present results demonstrate that the neurons providing the major CEA outputs to the brainstem receive an extensive GABAergic innervation, strongly supporting our proposal that CEA efferent neurons are under strong tonic inhibition by intrinsic GABAergic neurons. Further, our finding that the major cortical input to the central nucleus preferentially innervates intrinsic GABAergic neurons suggests that these neurons in the CEA may serve as an interface between the principal inputs and outputs of this forebrain region.

[A study on the transcriptional expression of oncogenes in human primary brain tumors]

The c-myc, L-myc, N-myc, Ha-ras, c-fos, and v-erbB oncogenes were used as probes to detect the total RNA of 5 cases of normal human brain tissues and 29 cases of brain tumor tissues by RNA dot hybridization analysis. The results showed that the increasing expressions of cerbB and c-fos were the highest, being 88.2% and 82.4%, respectively, the next was c-myc with an increased expression of 46.1%; the increasing expressions of L-myc (29.3%) and N-myc (31.6%) were observed in a few samples only. There was no significant difference of Ha-ras gene expression between normal brain and brain tumor. In addition, we observed the increasing expression of more than one oncogene in one sample. These results suggest that c-erbB and c-fos oncogenes may play an important role in the pathogenesis of human primary brain tumors, and that multiple genetic changes are implicated in genesis of human brain tumors.

Intrinsic GABAergic neurons in the rat central extended amygdala

The present study examined the distribution, morphology, and connections of gamma-aminobutyric acid-immunoreactive (GABA-IR) neurons in the three principal components of the central extended amygdala: the central amygdaloid nucleus, the bed nucleus of the stria terminalis (BNST) and the sublenticular substantia innominata. In the central nucleus, large numbers of GABA-IR neurons were identified in the lateral, lateral capsular, and ventral subdivisions, though in the medial subdivision, GABA-IR neurons were only present at very caudal levels. Combined immunocytochemistry-Golgi impregnation revealed that GABA-IR neurons in the lateral central nucleus were medium-sized spiny neurons that were morphologically similar to GABAergic neurons in the striatum. Injections of horseradish peroxidase into the bed nucleus of the stria terminalis labeled a major proportion of the GABA-IR neurons in the central nucleus. In the bed nucleus, the majority of GABA-IR neurons were located in the anterolateral subdivision, ventral part of the posterolateral subdivision and the parastrial subdivision. GABA-IR neurons in the anterolateral bed nucleus were of the typical medium-sized spiny type. Injections of horseradish peroxidase into the central nucleus labeled a few GABA-IR neurons in the posterior part of the anterolateral bed nucleus. GABA-IR neurons were identified in the sublenticular substantia innominata and medial shell of the nucleus accumbens and contributed to the continuum of GABA-IR extending from the central nucleus to the bed nucleus. Injections of horseradish peroxidase (HRP) into the central nucleus, but not the BNST, labeled a few GABA-IR neurons in the substantia innominata. The data point to GABA-IR neurons being a characteristic feature of the central extended amygdala and that GABA-IR neurons participate in the long intrinsic connections linking the major components of this structure. Since lesions of the stria terminalis and basolateral amygdaloid nucleus failed to deplete GABA-IR terminals in the central nucleus, the role of GABA in local and short intrinsic connections in the central extended amygdala is discussed. Further, physiological findings implicating the intrinsic GABAergic system of the central extended amygdala in the tonic inhibition of brainstem efferents are reviewed.

Selective suppression by bunazosin of alpha-adrenergic agonist evoked elevation of intraocular pressure in sympathectomized rabbit eyes

PURPOSE

To determine whether there is alpha 1-adrenergic receptor heterogeneity associated with the regulation of intraocular pressure (IOP) and mydriasis in rabbits, the authors tested the hypothesis by characterizing the ability of the selective alpha 1-adrenergic antagonist, bunazosin, to block the ocular hypertensive and mydriatic responses to alpha 1-adrenoceptor stimulation by either norepinephrine (NE) or phenylephrine (PE).

METHODS

The effects of topical application of bunazosin on IOP and pupillary diameter were measured in unilateral superior cervical ganglionectomized (SCGX) rabbits after exposure to either NE or PE.

RESULTS

Bunazosin (0.1%) alone only lowered the IOP in the normal eye and did not elicit a pupillary response on either side. NE (0.01-1.0%) by itself caused a concentration-dependent rise in IOP on both sides, but mydriasis did not occur on the normal side. In SCGX eyes, the sensitivity of the IOP response to NE increased tenfold over that measured on the normal side. Unlike on the normal side, concentration-dependent mydriatic responses occurred with 0.1 and 1% NE. After pretreatment with bunazosin (0.1%), neither NE (0.1%) nor PE (0.1%) evoked a rise in IOP. However, the mydriatic response to either one of these agonists in the SCGX eyes was less affected. By contrast, pretreatment with the alpha 2-adrenergic antagonist, 0.5% yohimbine, did not change the IOP increase elicited by 0.1% NE.

CONCLUSIONS

These results suggest that the alpha 1-adrenergic receptors that regulate IOP and pupillary diameter are different from one another in the rabbit.

Detection of point mutations of the phenylalanine hydroxylase gene and prenatal diagnosis of phenylketonuria

The known mutant alleles of the human phenylalanine hydroxylase (PAN) gene were analyzed in 25 phenylketonuria (PKU) families from North China by using polymerase chain reaction and allele-specific oligonucleotide dot blot hybridization techniques. The results showed that the six mutations analyzed accounted for 62% of all PKU genes. The three most frequent mutations were R243Q, R413P and Y204C. Seven prenatal gene diagnoses were carried out in 6 PKU families and were confirmed after birth or by examination of aborted materials.

[Effect of trigeminal denervation on rabbit corneal epithelium]

To investigate the effects of trigeminal denervation on the corneal epithelium, left postganglionic trigeminal neurotomy via intracranial approach was performed in 22 rabbits. Among 16 rabbits survived successfully, 13 denervated eyes (81%) showed corneal epithelial abnormalities that included 4 epithelial defects and 9 epithelial opacities. The remaining 3 eyes were normal. Histological examination showed many atrophic epithelial cells and the thinning of the corneal epithelial layer in the denervated eyes with corneal opacities. There was no abnormality in corneal stroma or endothelium. The ratio of epithelial to total corneal thickness calculated by a computer-assisted image analyzer was 6.5 +/- 2.1 (%) in control eyes and 3.8 +/- 1.9 (%) in the denervated eyes, the two values being significantly statistically different (p less than 0.001).

[Effects of insulin on expression of oncogenes in CWE mouse brain]

By RNA dot blot hybridization, we observed the expression of c-myc, c-fos, Ha-ras and erbB genes in normal brain of CWE mouse after the injection of insulin. Transcription of the c-myc and c-fos genes is greatly increased, which peaks approximately 2 h after insulin stimulation, decreases in 6 h and returns to the initial levels within 48 h. The alteration in Ha-ras transcription appears more complex; its expression decreases first but increases subsequently. We also detected the expression of erbB gene which decreases after the injection of insulin. The results suggest that c-myc, c-fos, Ha-ras and erbB might be directly involved in growth control. Their protein products might play a role in intracellular signal transduction.

[The expression of oncogenes in the development of human brain]

Seven oncogenes (c-myc, L-myc, N-myc, v-erbB, c-fos, Ha-ras and mos) were used as the probe to detect the total RNA of every part (cerebellum, temporal folium, frontal folium and occipital folium) in human brain from 2 cases of 6 mon fetus and the total RNA in fetal development (4 mon, 5 mon, 6 mon, 7 mon, and newborn) of human brain tissue by RNA dot hybridization analysis. The results showed that most oncogenes were expressed at high level in cerebellum and occipital folium of 6 mon fetus and at low level in temporal folium; there was similar expression of c-myc, L-myc and N-myc in fetal development of human brain tissue, and the highest level was in the 5 mon fetal brain. There was no expression of erbB gene in normal human brain. The high level expression of Ha-ras and c-fos genes was in the middle and later stages of fetal development. These results suggested that c-myc, L-myc, N-myc, erbB, Ha-ras, c-fos and mos genes might play an important role in the fetal development of human brain.

[A review on the chemical constituents of Annona plants]

The paper reviews the progress in the research on Annona plants, including the structure of chemical constituents, spectroscopic characteristics and physiological activities. A new kind of anticancer constituent is also introduced.