[Characteristics of peripheral blood leukocyte differential counts in patients with COVID-19]

To investigate the early changes of peripheral blood leukocyte differential counts in patients with COVID-19. Ten patients with COVID-19 and 30 patients with other viral pneumonia (non-COVID-19) admitted to Shanghai Jiao Tong University Affiliated Sixth People's Hospital and Jinshan Branch Hospital from January 22 to February 17, 2020 were enrolled in this study. The differential counts of white blood cells were analyzed. Patients in COVID-19 group showed relatively lower absolute white blood cell (WBC) count 4.95(3.90,6.03)×10(9)/L, lymphocyte absolute count 1.20(0.98,1.50)×10(9)/L and eosinophil absolute count 0.01(0.01,0.01)×10(9)/L. Leukopenia developed in two patients(2/10), lymphocytopenia also in two patients(2/10). Seven over ten patients presented with eosinophil cytopenia. In non-COVID-19 group, absolute WBC count was 8.20 (6.78,9.03) ×10(9)/L (P<0.001), lymphocyte absolute count 1.75(1.20,2.53)×10(9)/L(P=0.036), eosinophil absolute count 0.02(0.01,0.03)×10(9)/L(P=0.05). Lymphocytopenia occurred in (16.7%) patients, eosinophil cytopenia in 16.7% patients too. In conclusion, leukopenia, lymphocytopenia and eosinophil cytopenia are more common in COVID-19 patients than those in non- COVID-19 patients.

[Expression profiles of long non-coding RNAs in human liver cell line LO2 with stable expression of hepatitis B x gene]

OBJECTIVE

To investigate the differential expression profiles of long non-coding RNAs (lncRNAs) in human liver cell line LO2 with stable expression of hepatitis B x (HBx) gene, and to screen out the lncRNAs which play an important role in HBV-related liver cancer.

METHODS

The lncRNA microarray was used to establish the differential expression profiles of lncRNAs, and the methods such as scatter plots and cluster analysis were used to obtain the HBx-related lncRNAs with differential expression. The qRT-PCR was used to verify some lncRNAs with differential expression. The t-test was used to compare the expression of lncRNAs between the two microarray groups, and hierarchical cluster analysis was used for the original data of lncRNAs with differential expression.

RESULTS

Compared with the control group transfected with blank plasmids (L02/pcDNA3.0), LO2/HBx cells had 323 lncRNAs with > 2-fold upregulation and 421 lncRNAs whose expression was reduced by more than 50% (P < 0.05). The results of qRT-PCR verified 4 upregulated lncRNAs (TCONS_00006195, ENST00000557524, NR_037597, and ENST00000539975) and 3 downregulated lncRNAs (ENST00000508424, ENST00000447433, and uc001lva.4), which were consistent with the results of microassay.

CONCLUSION

HBx-related lncRNAs are successfully screened out, which lays a foundation for further investigation of the role of lncRNAs in the pathogenesis of liver cancer.

Stability and chaotification of vibration isolation floating raft systems with time-delayed feedback control

This paper presents a systematic study on the stability of a two-dimensional vibration isolation floating raft system with a time-delayed feedback control. Based on the generalized Sturm criterion, the critical control gain for the delay-independent stability region and critical time delays for the stability switches are derived. The critical conditions can provide a theoretical guidance of chaotification design for line spectra reduction. Numerical simulations verify the correctness of the approach. Bifurcation analyses reveal that chaotification is more likely to occur in unstable region defined by these critical conditions, and the stiffness of the floating raft and mass ratio are the sensitive parameters to reduce critical control gain.

Toluidine blue-mediated photodynamic therapy of oral wound infections in rats

The purpose of this study was to examine the effect of toluidine blue (TB)-mediated photodynamic therapy (PDT) on oral wound infections in rats. The study called for a combination treatment of a 1mg/ml solution of TB with a red light at three intensity settings of 12 J/cm(2), 24 J/cm(2) and 48 J/cm(2). In the group that was given the highest light dose of 48 J/cm(2), an average kill rate of approximately 97% was achieved. A lesser killing effect was achieved in the group that was subjected to the lowest light dose of 12 J/cm(2), where an average of approximately 25% of the bacteria survived. After PDT, the lesions were allowed to develop, and the peak size of the lesions was larger in the control group than in the test groups, especially for the 48 J/cm(2) group. We also observed that in the 24 J/cm(2) and 48 J/cm(2) groups the lesions were of significantly smaller size. Our study demonstrated that combined TB-PDT therapy can successfully treat oral wound infections in rats. These promising results recommend the use of this treatment as a possible alternative to topical anti-microbials in future clinical applications.

Congenital nasal pyriform aperture stenosis with semilobar holoprosencephaly

We describe a child who has congenital nasal pyriform aperture stenosis with single maxillary central incisor, holoprosencephaly and central diabetes insipidus without any apparent anterior pituitary dysfunction. Conservative management of the congenital nasal pyriform aperture stenosis is adopted and management of diabetes insipidus is described. A literature review is undertaken.

Hepatotoxicity and persistent renal insufficiency after repeated supratherapeutic paracetamol ingestion in a Chinese boy

Paracetamol has always been regarded as a useful and safe drug. The risk of toxicity with repeated supratherapeutic paracetamol is an underrecognised condition. We report on a 12-month-old boy who presented with hepatotoxicity, disseminated intravascular coagulation and persistent renal insufficiency 4 days after repeated ingestion of a supratherapeutic dosage of paracetamol. To the best of our knowledge, this is the first reported case of paediatric chronic paracetamol poisoning among the Chinese population. In addition, persistent renal insufficiency has not been a previously reported feature of chronic paracetamol poisoning. We propose that renal damage is the result of the synergistic effect of hypoperfusion and paracetamol overdose.

Decreased tissue plasminogen activator and increased plasminogen activator inhibitors and increased activator protein-1 and specific promoter 1 are associated with inhibition of invasion in human A375 melanoma deprived of tyrosine and phenylalanine

We previously found that dietary tyrosine (Tyr) and phenylalanine (Phe) restriction significantly decreased the metastatic phenotype of the pigmented murine B16BL6 melanoma in vivo and decreased the in vitro invasion of these cells. Here we report that invasion and chemoinvasion through GFR Matrigel of the human amelanotic A375 melanoma also is significantly inhibited by Tyr and Phe deprivation in vitro. Deprivation of these two amino acids decreased the secretion and protein expression of tissue-type plasminogen activator (tPA) while expression and secretion of plasminogen activator inhibitor (PAI-1 and PAI-2) were increased. Moreover, nuclear extracts of Tyr- and Phe-deprived cells exhibited increased binding of the transcription factors, activator protein-1 (AP-1) and specific promoter-1 (Sp1), to consensus oligonucleotides as determined by electrophoretic mobility shift assay. Nuclear binding activity to the oligonucleotide consensus sequence for AP-1 was inhibited by antibody against c-Fos and more effectively inhibited by an antibody against c-Jun. We conclude that decreased invasion and chemoinvasion of A375 melanoma cells deprived of Tyr and Phe are related to decreased secretion of tPA and increased secretion of PAIs. Increased AP-1 and Sp1 binding implicates these transcription factors in the regulation of PAI expression.

Inhibition of B16BL6 melanoma invasion by tyrosine and phenylalanine deprivation is associated with decreased secretion of plasminogen activators and increased plasminogen activator inhibitors

We previously found that dietary tyrosine (Tyr) and phenylalanine (Phe) limitation significantly decreased the metastatic phenotype of B16BL6 melanoma cells in vivo and decreased the in vitro invasion of these cells. To more specifically characterize the effects of Tyr and Phe deprivation we examined the three steps involved in invasion: attachment to host cells and components, elaboration of proteases that degrade basement membranes, and migration of invading tumor cells. Here we report that B16BL6 melanoma cell invasion through growth factor reduced (GFR) Matrigel is significantly decreased by Tyr and Phe deprivation. Tyr and Phe deprivation in vitro decreased the attachment of B16BL6 melanoma cells to GFR Matrigel, heparin sulfate proteoglycans (HSPG), neonatal murine epidermal (NME) cells and the extracellular matrix (ECM) from these cells. These cells also exhibited a decrease in chemotactic response to fetal bovine serum (FBS). Deprivation of these two amino acids decreased the secretion of urokinase plasminogen activator (uPA) and tissue plasminogen activator (tPA) while plasminogen activator inhibitor (PAI)-1 and -2 were increased in these cells. These observations suggest that Tyr and Phe deprivation decreases the in vitro chemotactic and invasive ability of B16BL6 melanoma cells by decreasing attachment and secreted PA activity and by increasing secreted PAIs in these cells.

Histopathological examination of chemo-sympathectomy in cats

In recent decades, there has been an increase in both the number of sympathectomy techniques, as well as the surgical findings of sympathetic anatomy. Currently the advanced technique of C-arm guided percutaneous thoracic chemo-sympathectomy is widely used for the treatment of palmar hyperhidrosis. However, a better understanding of chemical agents in sympathectomy is required. In this study, chemo-sympathectomy was performed in cats, using alcohol, glycerol and various concentrations of phenol, to determine the chronic neurotoxic effects of these chemical agents on the stellate ganglia. The stellate ganglia of 24 cats were exposed under endotracheal general anesthesia, then injected with about 0.02 ml of absolute alcohol, glycerol and phenol (10%, 25%, 50%, and 75% concentration) solutions, respectively. The stellate ganglia were taken for histological examination three weeks after the chemical injection. The results showed that the degenerative changes in the cytoplasm and nucleus of ganglionic cells and intercellular tissue were moderate and relatively moderate after the injection of alcohol and glycerol, respectively. Meanwhile, the stellate ganglia revealed mild, relatively moderate, serious and extremely serious degeneration after injection of 10%, 25%, 50%, and 75% phenol, respectively. In conclusion, we recommend a high concentration of phenol, in the least volume, as a chemical agent for clinical injection in the upper thoracic sympathetic ganglion.

Focal adhesion kinase-dependent apoptosis of melanoma induced by tyrosine and phenylalanine deficiency

We found previously that restriction of tyrosine (Tyr) and phenylalanine (Phe) inhibited growth and metastasis of B16BL6 murine melanoma and arrested these cells in the G0-G1 phase of the cell cycle. Here, we report that deprivation of these two amino acids in vitro induces apoptosis in B16BL6 and in human A375 melanoma cells but not in nontransformed, neonatal murine epidermal cells or human infant foreskin fibroblasts. Four days after deprivation of Tyr and Phe in vitro, 37% of B16BL6 and 51% of A375 melanoma cells were undergoing apoptosis. Apoptosis was not associated with elevation in intracellular calcium or alteration in p53 or c-myc protein expression. Expression and Tyr phosphorylation of focal adhesion kinase (FAK) were inhibited in both melanoma cell lines by deprivation of Tyr and Phe but not by deprivation of glutamine or serum. Tyr phosphorylation of FAK in Tyr- and Phe-deprived melanoma cells was enhanced within 30 min of refeeding with complete DMEM. FAK protein expression recovered within 60 min, and cell viability recovered within 24 h. Genistein, a tyrosine kinase inhibitor that specifically inhibits Tyr phosphorylation of FAK, did not induce apoptosis in A375 melanoma cells at a concentration of 50 microM. Genistein prevented the recovery of cell viability upon refeeding with Tyr and Phe to previously deprived A375 melanoma cells. These data collectively indicate that apoptosis induced by Tyr and Phe deprivation is FAK-dependent.

Influence of tyrosine and phenylalanine limitation of cytotoxicity of chimeric TGF-alpha toxins on B16BL6 murine melanoma in vitro

Previous research in animals supports the use of tyrosine and phenylalanine (Tyr-Phe) restriction as an adjuvant to the treatment of cancer. In this regard, dietary restriction of Tyr-Phe specifically inhibits the growth of B16BL6 melanoma tumors, dramatically suppresses spontaneous hematogenous metastasis, and modulates the sensitivity of these tumor cells to growth factors. Two chimeric toxins, HB-TGF alpha-PE4EKDEL and TGF alpha-PE4EKDEL, were examined for their toxicity against the B16BL6 melanoma cell line, and the ability of Tyr-Phe limitation to modulate the potential of these toxins was examined. Tyr-Phe limitation significantly enhanced the cytotoxic effects of HB-TGF alpha-PE4EKDEL approximately 10-fold toward B16BL6 melanoma, and free heparin diminished the cytotoxicity of HB-TGF alpha-PE4EKDEL. Although TGF alpha-PE4EKDEL is cytotoxic to this cell line, Tyr-Phe limitation did not effect the cytotoxicity of this toxin. Tyr-Phe limitation inhibited the synthesis and secretion of heparin-binding proteins but did not alter the expression of surface heparan sulfate proteoglycans. These data suggest that cell surface heparan sulfate proteoglycan is a target for binding and execution of the cytotoxicity of HB-TGF alpha-PE4EKDEL and that augmentation of cytotoxicity by Tyr-Phe limitation is due to the inhibition of heparin-binding protein production.

Tyrosine and phenylalanine restriction induces G0/G1 cell cycle arrest in murine melanoma in vitro and in vivo

Tyr-Phe and Met limitation in vitro inhibited cell proliferation and proliferating cell nuclear antigen (PCNA) expression to a greater extent than serum limitation. Tyr-Phe and serum limitation arrested cells in the G0/G1 phase; Met limitation blocked cells in the G0/G1 and S phases. Tyr-Phe limitation progressively decreased cyclin D1 expression to 30% of control within four days and did not affect expression of cyclin D3 or cyclin-dependent kinase (CDK2, CDK4, and CDK5) expression, Met limitation decreased cyclin D3 expression to 25% of control and CDK2 expression to 32% of control by Day 4 and did not affect expression of cyclin D1, CDK4, and CDK5. Serum limitation inhibited cyclin D1 and cyclin D3 expression to 24% of control after four days and did not effect CDK expression. Expression of two CDK inhibitors, p21WAF1/Cip1 and p27Kip1, was not changed by amino acid or serum limitation. Dietary restriction of Tyr-Phe in mice bearing subcutaneous B16BL6 melanoma tumors decreased tumor growth rate compared with mice fed a normal diet. Tumors from Tyr-Phe-restricted mice exhibited decreased PCNA expression, G0/G1 phase cell cycle arrest, and reduced cyclin D1 expression. These data indicate that decreased tumor growth in vivo associated with dietary restriction of Tyr and Phe is cell cycle specific.

Evaluation of laser and radiofrequency induced dorsal root entry zone lesion for pain control in rats

BACKGROUND

Dorsal root entry zone (DREZ) lesions have been believed to be effective for control of intractable pain. These lesions are usually made using radiofrequency (RF) technique. Theoretically, laser can provide very fast, precise, reproducible and easy control of photothermal effect, possibly achieving better pain control than RF. The objective here was to learn more about the effect of pain control among the RF, carbon dioxide (CO2) laser and potassium titanyl phosphate (KTP) laser in rats.

METHODS

The adult rat was anesthetized and the dorsal spinal cord from C5 to T1 was exposed under a microscope. The DREZ lesions were created in each group of eight including sham, RF thermocoagulation, CO2 laser and KTP laser. The latency of pain withdrawal in the fore-paw by a hot-plate test was recorded before the DREZ lesions and three weeks afterward.

RESULTS

The data showed that RF, CO2 and KTP laser could significantly reduce pain in rats (p < 0.05, one-way ANOVA and Dunnett's test). Latencies of pain withdrawal in the fore-paw by the hot-plate test before, and three weeks after, DREZ lesions were 13.9 +/- 1.4 sec and 65.2 +/- 4.9 sec in the RF group, 15.9 +/- 1.4 sec and 59.0 +/- 5.9 sec in the CO2 laser group, and 14.1 +/- 0.9 sec and 64.8 +/- 5.7 sec in the KTP group, respectively.

CONCLUSIONS

The density of opioid receptor in DREZ lesions cord showed no significant change three weeks after operation in the sham and CO2 laser groups. It was concluded that DREZ lesions caused by RF, CO2 laser and KTP laser can achieve pain control significantly in the rats. The effect of KTP laser was close to RF, followed by CO2 laser.

Expression and subcellular distribution of basic fibroblast growth factor are regulated during migration of endothelial cells

Migration of endothelial cells is involved in normal and pathological angiogenesis and in re-endothelialization after vascular injury or rupture of atherosclerotic plaques. Several types of endothelial cells are known to synthesize basic fibroblast growth factor (bFGF); in some of these, migration is increased by exogenous bFGF and inhibited by anti-bFGF antibodies. Using immunocytochemical techniques and RNase protection analysis, we studied endothelial cells from bovine coronary arteries and veins as well as from adrenal microvessels. We found that bFGF mRNA and peptide were present in confluent endothelial cells and were upregulated during migration stimulated by removal of some cells from the monolayer. During migration, extracellular matrix stores of bFGF were depleted, and bFGF immunoreactivity began to accumulate in the cytoplasm of endothelial cells between 2 and 6 hours. After migration had begun, but before the initiation of DNA synthesis, bFGF immunoreactivity increased in the nuclei and nucleoli. Exogenous bFGF stimulated endothelial migration, and antibodies to bFGF markedly inhibited migration, suggesting that an intracrine function of nuclear bFGF is not sufficient for cell migration. In all three types of endothelial cells studied, bFGF was identified as an endogenous regulator, but not as the sole regulator, or migration. Moreover, bFGF expression and subcellular localization were found to be regulated during endothelial cell migration.

Smooth muscle cell abundance and fibroblast growth factors in coronary lesions of patients with nonfatal unstable angina. A clue to the mechanism of transformation from the stable to the unstable clinical state

BACKGROUND

The mechanisms responsible for the transformation of stable angina to unstable angina, a major cause of morbidity and mortality, are commonly believed to be plaque rupture and thrombosis. We determined whether additional mechanisms are operative by analyzing the histopathology and immuno-histopathology of coronary plaques retrieved by directional atherectomy of patients with unstable angina in whom no intraluminal thrombus was demonstrated by angiography.

METHODS AND RESULTS

The histological findings of atherectomy specimens from 34 patients with unstable angina were compared with those of 24 patients with postangioplasty restenosis, whose lesions are known to be composed of smooth muscle cells (SMCs), and 10 patients with stable angina, whose lesions contain relatively few SMCs. We also studied the expression of acidic and basic fibroblast growth factors (aFGF and bFGF), whose role in the vascular response to injury has been established. Specimens from unstable angina resembled those from postangioplasty restenosis in regard to SMC abundance (scale, 0 to 3; 1.4 +/- 0.9 versus 1.7 +/- 0.9; P = NS), and both differed from those of stable angina. Thrombus and/or hemorrhage occurred in only 34% of patients with unstable angina (compared with 8% of restenosis patients and in none of stable angina patients). Active lesions (defined as lesions (defined as lesions containing one or more of the following: thrombus, hemorrhage, abundant and disorganized SMCs in the presence of loose connective tissue, or inflammatory infiltrate) were observed in 56% of the unstable angina patients and in 50% of the restenosis patients but in none of the stable angina patients. The expression of aFGF and bFGF was detected in 80% to 100% of unstable angina (n = 11) and restenosis (n = 10) specimens but in only 1 of 5 stable angina specimens.

CONCLUSIONS

Microscopic evidence of thrombosis and plaque rupture occurred in only one third of unstable angina patients, selected because they had no angiographic evidence of intracoronary thrombus. Moreover, their lesions resembled those of restenosis patients in regard to SMC abundance, lesion activity, and the expression of aFGF and bFGF. Our findings therefore suggest that an alternative mechanism to plaque rupture and thrombus formation may be operative in the precipitation of unstable angina; namely, in a subset of patients, SMC proliferation may lead to gradual plaque expansion and thereby to lumenal narrowing and unstable angina. Our data also suggest a role for aFGF and bFGF in this process.

Cytotoxic effects of vascular smooth muscle cells of the chimeric toxin, heparin binding TGF alpha-Pseudomonas exotoxin

OBJECTIVE

Smooth muscle cell proliferation appears to be very important in restenosis after angioplasty. A chimeric toxin created by genetically fusing the gene encoding TGF alpha (targets the EGF receptor) to the gene encoding Pseudomonas exotoxin (PE) preferentially kills rapidly proliferating smooth muscle cells. Recently, a heparin binding EGF-like growth factor (HB-EGF) has been identified. The HB domain enhances the mitogenic activity for smooth muscle cells. The purpose of this study was to design a new chimeric toxin, having both heparin binding and EGF receptor binding function, and to determine whether it is more cytotoxic to smooth muscle cells.

METHODS

By recombinant DNA techniques, a new chimeric toxin, HB-TGF alpha-PE4EKDEL, was synthesised. Cytotoxic assays were performed by assessing the capacity to inhibit protein synthesis of rat vascular smooth muscle cells.

RESULTS

The toxin preferentially killed rapidly proliferating smooth muscle cells (p < 0.025). The HB domain increased the cytotoxicity of the molecule when compared to the other chimeric toxins tested against smooth muscle cells. The cytotoxic effect of the new molecule was significantly decreased by exogenously added heparin (p < 0.05).

CONCLUSIONS

The presence of a heparin binding domain increases the smooth muscle cell cytotoxicity of the TGF alpha fusion toxin, perhaps because HB-TGF alpha-PE4EKDEL functions as a molecule with two ligands. It will be important to determine whether the greater smooth muscle cell cytotoxicity that exists in vitro will facilitate the specific targeting and killing of rapidly proliferating cells in vivo.

Heparin-binding transforming growth factor alpha-Pseudomonas exotoxin A. A heparan sulfate-modulated recombinant toxin cytotoxic to cancer cells and proliferating smooth muscle cells

TGF alpha-PE40, a recombinant toxin in which transforming growth factor alpha (TGF alpha) is fused to a mutant form of Pseudomonas exotoxin, is selectively cytotoxic to cells bearing epidermal growth factor (EGF) receptors. Heparin binding EGF-like growth factor is a potent mitogen for smooth muscle cells capable of binding to both the EGF receptor and to immobilized heparin (Higashiyama, S., Abraham, J., Miller, J., Fiddes, J., and Klagsbrun, M. (1991) Science 251, 936-938). To study the effect of the heparin-binding domain in a chimeric toxin targeted to the EGF receptor, we fused the DNA sequence corresponding to the putative NH2-terminal heparin-binding (HB) domain of HB-EGF to chimeric toxins composed of TGF alpha and two different recombinant forms of Pseudomonas exotoxin (PE). One of these is a truncated form of PE devoid of the binding domain (TGF alpha-PE38); another is a mutant form of full-length toxin containing inactivating mutations in the binding domain and an altered carboxyl terminus (TGF alpha-PE4EKDEL). The resulting chimeric toxins HB-TGF alpha-PE38 and HB-TGF alpha-PE4EKDEL were expressed in Escherichia coli as inclusion bodies, refolded, and purified by heparin affinity chromatography. Both of the toxins were eluted from heparin at 0.8 M NaCl, in contrast to their respective TGF alpha toxins which were eluted at 0.15 M. Binding studies on A431 cells showed that the HB-TGF alpha toxins bound to the EGF receptor with an affinity similar to that of the TGF alpha toxins. However, cell killing studies on a panel of malignant cell lines showed that cytotoxicity was strongly affected by the presence of the HB domain. Cell lines expressing high numbers of EGF receptors such as A431 and KB were less sensitive to toxins containing the HB domain. Cells with low number of EGF receptors had similar responses to both types of toxins (MCF-7 and LNCaP) or were more sensitive to the toxin with the added HB domain (HEP-G2). HB-TGF alpha-PE4EKDEL was over 10-fold more cytotoxic against proliferating vascular smooth muscle cells (VSMC) than to quiescent VSMC. Moreover, HB-TGF alpha-PE4EKDEL was 6-fold more potent than TGF alpha-PE4EKDEL to proliferating VSMC. Competition studies with EGF and/or heparin showed that heparin blocks the cytotoxicity of HB-TGF toxins and the inhibitory action of heparin is stronger in cells expressing lower number of EGF receptors.(ABSTRACT TRUNCATED AT 400 WORDS)

Localization of basic fibroblast growth factor in bovine endothelial cells: immunohistochemical and biochemical studies

To gain insight into the mechanisms of synthesis, storage, and release of basic fibroblast growth factor (bFGF), we studied the immunohistochemical localization of bFGF in bovine coronary artery, coronary sinus, and adrenal capillary endothelial cells grown in culture. Light and electron microscopic immunohistochemical studies were performed using the ABC immunoperoxidase method on p-formaldehyde-fixed cells. Five different anti-bFGF antibodies gave similar results in all cell types. In subconfluent cells, immunoreactivity was noted in the nuclear chromatin, nucleoli, cytosol, cytoplasmic vesicles (some of which appeared to fuse with the plasma membrane), and extracellular matrix. No reaction was found in endoplasmic reticulum or Golgi zones. Confluent cells demonstrated less immunoreactivity in the nuclei and cytosol but more in the extracellular matrix. Some cells of senescent morphology showed only cytoplasmic staining; however, no cells were found with only nuclear staining. Biochemical studies showed that three forms of bFGF (18, 24, and 26 kDa) were present in endothelial cells and varied with different culture conditions. Protection analysis indicated that bFGF mRNA is less abundant in postconfluent cells than in subconfluent cells. These data suggest that subconfluent cells synthesize bFGF and transport it into the nucleus and exocytotic vesicles, while confluent cells synthesize little bFGF but store it in extracellular matrix, cytoplasmic vesicles, and nuclei.

Inhibitory effects of antisense oligodeoxynucleotides targeting c-myc mRNA on smooth muscle cell proliferation and migration

Smooth muscle cell (SMC) proliferation and migration play pivotal roles in restenosis following angioplasty. c-myc is an immediate early response gene induced by various mitogens, and several lines of evidence derived from experiments using transformed or hematopoietic cell lines, or transgenic mice, suggest its protein product plays a role in numerous signaling transduction pathways, including those modulating cell division. We therefore reasoned that a strategy employing oligodeoxynucleotides (ODNs) complementary to c-myc mRNA (antisense ODNs) might be potent inhibitors of SMC proliferation and, perhaps, of SMC migration. To evaluate this concept, we tested several antisense ODNs targeted to c-myc mRNA (15- or 18-mer ODNs complementary to different c-myc mRNA sequences) by introducing them individually into the medium of cultured rat aortic SMCs. Phosphoroamidate-modified ODNs were employed to retard degradation. Antisense ODNs inhibited, in a concentration-dependent manner, SMC proliferation and SMC migration. Maximal inhibitory effect was 50% for proliferation and > 90% for migration. These effects were associated with decreased SMC expression of c-myc-encoded protein by Western immunoblotting and immunocytochemical staining. ODNs with the same nucleotides but a scrambled sequence caused no effect. These results indicate that the c-myc gene product is involved in the signal transduction pathways mediating SMC proliferation and migration in the in vitro model we employed. The results also suggest a potential role of antisense strategies designed to inhibit c-myc expression for the prevention of coronary restenosis.

Enterogenous cyst of the fourth ventricle: case report

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

In vitro effects of a recombinant toxin targeted to the fibroblast growth factor receptor on rat vascular smooth muscle and endothelial cells

The dominant mechanism responsible for restenosis after angioplasty is believed to be the activation of medial smooth muscle cells (SMCs), leading to their proliferation, migration to the subintima, and further proliferation. To develop novel strategies that might inhibit or prevent restenosis, we previously used a chimeric toxin composed of transforming growth factor-alpha (which targets the epidermal growth factor receptor) and mutated Pseudomonas exotoxin to preferentially recognize and kill rapidly proliferating, versus quiescent, vascular SMCs. We have recently cloned and expressed a recombinant gene encoding Pseudomonas exotoxin with a mutated (nonfunctional) cell recognition domain fused with the ligand acidic fibroblast growth factor, termed aFGF-PE66(4Glu)KDEL; thus, this recombinant toxin targets the fibroblast growth factor receptor. In the present study, we evaluated the relative effects of this chimeric toxin on quiescent versus rapidly proliferating vascular SMCs and also determined whether aFGF-PE66(4Glu)KDEL exerted different effects on SMCs versus endothelial cells. Rapidly proliferating SMCs (grown in 10% fetal bovine serum) were very sensitive to the cytotoxic effects of aFGF-PE66(4Glu)KDEL, whereas cytotoxicity was significantly less when the SMCs were in a quiescent state (grown in medium supplemented with 0.5% fetal bovine serum). The chimeric toxin was also significantly less cytotoxic against endothelial cells. Competition studies using excess acidic fibroblast growth factor indicated that the cytotoxic effects are specifically mediated by the fibroblast growth factor receptor. Thus, the present studies suggest a potentially expanded role of recombinant toxin therapy in restenosis: multiple receptors can be targeted, and cytotoxic effects, at least in vitro, can be preferentially directed to rapidly proliferating vascular SMCs, with relative sparing of vascular endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidic fibroblast growth factor in the developing rat embryo

Compared to basic fibroblast growth factor (bFGF), a widely distributed, broad spectrum mitogen and mesoderm inducer, acidic fibroblast growth factor (aFGF) is reported to have an essentially neural distribution and to be undetectable in the early embryo. In the present investigation, we used immunoblotting and immunochemistry to assess the cellular and tissue distributions of aFGF and bFGF in 11-20-d rat embryos. Immunoblotting of crude and heparin-bound embryo extracts revealed faint bands at the expected 17-18-kD and predominant bands at an apparent molecular mass of 26 to 28-kD (despite reducing conditions) using multiple specific antibodies for aFGF and bFGF. Pretreatment with 8 M urea yielded 18-20-kD aFGF and bFGF and some 24-26-kD bFGF. Immunoreactivity for both aFGF and bFGF was positive and similar in the cytoplasm, nuclei, and extracellular matrix of cells of neuroectodermal and mesodermal origin, while it was negative in endoderm-derived cells. The distribution of immunoreactive aFGF and bFGF also showed changes during development that were associated with the process of cellular and tissue differentiation. For example, intensity and extent of immunoreactivity for both peptides progressively increased in the middle layer of the spinal cord with increasing differentiation of the neural cells. The immunostaining patterns were very similar for aFGF and bFGF for each organ and at each stage. In conclusion, high molecular mass forms of immunoreactive aFGF and bFGF are present in the rat embryo. Acidic FGF and bFGF are both widely distributed in tissues of neuroectodermal and mesodermal origin, and their distribution was very similar.

Cytotoxic effects of a recombinant chimeric toxin on rapidly proliferating vascular smooth muscle cells

BACKGROUND

Restenosis after percutaneous transluminal coronary angioplasty is associated with activation of medial smooth muscle cells (SMCs); they proliferate, migrate to the subintima, and narrow the vessel lumen. Cancer cells often express more cell surface receptors than do normal cells. This has allowed tumor cells to be specifically targeted using cytotoxic agents. We have examined whether a similar concept can be applied to rapidly proliferating but nontransformed SMCs. Pseudomonas exotoxin (PE; MW, 66 kDa) is a potent toxin that kills cells by inhibiting protein synthesis; its toxicity is diminished when its cell recognition domain is deleted to produce a 40-kDa protein (PE40).

METHODS AND RESULTS

A complementary DNA encoding transforming growth factor alpha (TGF alpha) was ligated to that encoding PE40 and the chimeric toxin TGF alpha-PE40, which is cytotoxic to cancer cells displaying epidermal growth factor (EGF) receptors, was expressed in Escherichia coli. The ability of this toxin to kill proliferating SMCs was tested. When cells were seeded at low density (2,500 cells/cm2) and grown in medium supplemented with 10% fetal bovine serum, they were found to be rapidly proliferating; these cells were very sensitive to the cytotoxic effects of TGF alpha-PE40 (ID50, 4.0 +/- 0.17 ng/ml). In contrast, cytotoxicity was 30-fold less (ID50, 125 +/- 23 ng/ml; p less than 0.0004) when cells were in a quiescent state (grown in medium supplemented with 0.5% fetal bovine serum).

CONCLUSIONS

Competition studies using excess EGF indicated that the cytotoxic effects of TGF alpha-PE40 are specifically mediated by the EGF receptor. EGF receptor binding analysis demonstrated that rapidly proliferating SMCs display 10-fold more EGF receptors than do quiescent SMCs in vitro. Thus, a chimeric toxin targeted toward the EGF receptor can selectively kill rapidly proliferating SMCs. Whether this toxin or other chimeric toxins directed against other cell surface receptors will effectively inhibit SMCs proliferating in vivo or be useful in preventing restenosis remains to be determined.

Immunohistochemical localization of basic and acidic fibroblast growth factors in the developing rat heart

BACKGROUND

We used biochemical and immunohistochemical techniques to investigate the expression and distribution of immunoreactive basic and acidic fibroblast growth factors (bFGF and aFGF, respectively) in the hearts of rat embryos (11-20 days of gestation) and of postnatal rats (1-35 days after birth). Our purpose was to assess the relation between the cellular distribution of these growth factors and histogenetic and morphogenetic events in the developing heart.

METHODS AND RESULTS

Western-blot analysis of heparin-bound material from neonatal heart extracts identified a single band with a molecular weight of approximately 18 kD for both bFGF and aFGF. Five antibodies for bFGF and three for aFGF showed superimposable distribution of immunoreactive bFGF and aFGF in the heart at each stage examined. At the cellular level, these peptides were localized in the cytoplasm and extracellular matrix. In the myocytes, immunostaining was positive throughout the embryonic and neonatal periods. In the majority of the mesenchymal cells of the cushions and endothelial cells of endocardium and vessels, staining was also positive. In the smooth muscle cells of the aorta, other large arteries, and coronary arteries, immunostaining was intensely positive at early stages of development but became faint or negative with increasing cell differentiation.

CONCLUSIONS

The wide distribution of immunoreactive bFGF and aFGF that we identified in the developing rat heart suggests that these growth factors play an important role in heart cytodifferentiation and morphogenesis. Their superimposable distribution may reflect functional interaction. The progressive changes in their distribution suggest a changing role for these peptides during organogenesis.