[Occlusion with interrupted titanium clips for ruptured bullae under video-assisted thoracoscopic surgery]

Spontaneous pneumothorax is a common disease and as many as 20% of these patients should be operated because of a recurrent pneumothorax, persistent air leak, or failure to completely reexpand the lung. From January 1993 until March 1994, on the basis of experiment, we performed video-assisted thoracoscopic surgery (VATS) intervention and talc pleurodesis on 8 patients with spontaneous pneumothorax caused by ruptured bullae, and designed a new procedure of occluding the bullae with interruptured titanium clips. This procedure has some advantages of complete occlusion of lung tissue at the base of the bulla, minimal loss of lung tissue, effectively preventing leakage and recurrent pneumothoraces, and enough capacity of anti-tension while the lung expands. Also Authors have advocated giving a negative pressure suction to opsilateral lumen of the Carlen's tube interbation to visualize adequately the intrathoracic structures, while selective lung ventilation is performed. This method keeps hemodynamic stability and is performed more easily and safely than that of positive pressure insufflation is done. Postoperatively, complete lung expansion was obtained in all patients. There were no perioperative complications related to VATS, and no recurrences to date. These early results with thoracoscopic management of spontaneous pneumothorax caused by ruptured bullae have encouraging.

Observation of coherent reaction dynamics in heme proteins

Femtosecond laser pulses, resonant with Soret band of the nitric oxide complex of myoglobin (MbNO), were used to probe coherent, low-frequency nuclear motion of the heme group after photolysis. Distinct oscillations with periods of 430 and 150 femtoseconds were observed and are attributed to heme doming and iron-histidine motion, respectively. These results verify that the nuclear motion of the heme is strongly coupled to the ligand binding reaction and demonstrate that such motion is not determined by overdamped (diffusive) dynamics. The relative phases and frequencies of the nuclear motion of the photoproduct suggest that the coherence arises from impulsive electronic forces associated with the spin-state change of the heme iron atom and the depopulation of its dz2 orbital during the bond-breaking event.

Interaction of c-Myc with the pRb-related protein p107 results in inhibition of c-Myc-mediated transactivation

The product of the c-myc proto-oncogene, c-Myc, is a sequence-specific DNA binding protein with an N-terminal transactivation domain and a C-terminal DNA binding domain. Several lines of evidence indicate that c-Myc activity is essential for normal cell cycle progression. Since the abundance of c-Myc during the cell cycle is constant, c-Myc's activity may be regulated at a post-translational level. We have shown previously that the N-terminus of c-Myc can form a specific complex with the product of the retinoblastoma gene, pRb, in vitro. These data suggested a model in which pRb, or pRb-related proteins, regulate c-Myc activity through direct binding. We show here that the pRb-related protein p107, but not pRb itself, forms a specific complex with the N-terminal transactivation domain of c-Myc in vivo. Binding of p107 to c-Myc causes a significant inhibition of c-Myc transactivation. Expression of c-Myc releases cells from a p107-induced growth arrest, but not from pRb-induced growth arrest. Our data suggest that p107 can control c-Myc activity through direct binding to the transactivation domain and that c-Myc is a target for p107-mediated growth suppression.

Application of the external perichondrium of the ala of the thyroid cartilage of the nondiseased side in laryngeal surgery

Since 1976, in our department, the external perichondrium of the ala of the thyroid cartilage of the nondiseased side has been successfully applied in repairing endolaryngeal defects and reconstructing the laryngeal wall in 22 cases. The postoperative result was good in the most cases.

The endogenous vascular elastase that governs development and progression of monocrotaline-induced pulmonary hypertension in rats is a novel enzyme related to the serine proteinase adipsin

We showed previously a cause and effect relationship between increased activity of an endogenous vascular elastase (EVE) and experimentally induced pulmonary hypertension in rats. We now report the isolation and characterization of EVE. Degenerate oligonucleotides synthesized to homologous sequences in serine elastases were used in a PCR with rat pulmonary artery (PA) cDNA. The PCR product hybridized to a 1.2-kb mRNA and the intensity of hybridization was threefold increased in RNA from rat hypertensive PA at a timepoint when EVE activity was increased. The PCR product was used to screen a cDNA library and sequences obtained encoded rat adipsin. We then used immunoaffinity to purify EVE. An antibody to the elastin-binding protein was used to remove this competitor of elastase from the PA extract and the elastolytic activity increased 100-fold. The enzyme was purified using an antibody that recognizes NH2-terminal sequences of serine proteinases and the eluate was further purified using an antibody raised against recombinant adipsin. A single band at 20 kD immunoreactive with the adipsin antibody was resolved as an active enzyme on an elastin substrate gel. Immunogold labeling with an antibody to an adipsin peptide sequence localized EVE to PA smooth muscle cells. This is the first isolation of EVE; it appears to be a novel enzyme related to the serine proteinase adipsin originally found in adipose tissue.

The solution structure of the r(gcg)d(TATACCC):d(GGGTATACGC) Okazaki fragment contains two distinct duplex morphologies connected by a junction

Okazaki fragments are important intermediates in DNA replication. Chimeric duplexes that are structurally equivalent to Okazaki fragments also occur during reverse transcription of RNA retroviruses. Such duplexes consist of an RNA-DNA chimeric strand base-paired to a pure DNA strand; hence they have a hybrid duplex "left half" covalently linked to a "right half" that is pure DNA. We have determined the solution structure of the synthetic Okazaki fragment r(gcg)d(TATACCC):d(GGGTATACGC) by means of two-dimensional NMR, restrained molecular dynamics and full relaxation matrix simulation of the two-dimensional nuclear Overhauser effect spectra at various mixing times. The large negative x-displacement and large positive inclination in the hybrid section of the duplex are structural characteristics similar to those found in pure hybrid duplexes. However, the DNA sugar puckers and the width and depth of the minor groove in the pure DNA section are more like B-form DNA, especially beyond the junction. Thus, this Okazaki fragment duplex assumes a conformation in solution that is a chimeric mixture of hybrid-form (H-form) and B-form structures and the overall molecule cannot be classified as either an A-form or a B-form duplex. The co-existence of these two different conformations in a single duplex gives rise to a structural discontinuity with a bend of approximately 18.1 (+/- 0.4) degrees at the junction between the hybrid and DNA segments that may be important for reverse transcriptase binding and RNase H cleavage of such molecules. Despite the fact that the solution structure is quite different from the all A-form structure reported recently for the exact same molecule in the crystalline state, a surprising number of local helical parameters were found to be quite similar to those reported for the crystal structure.

The relationship of dietary animal protein and electrolytes to blood pressure: a study on three Chinese populations

The relationship of diet to blood pressure was studied in a total of 705 men and women aged 40-59 from three Chinese population samples having different mean blood pressure and dietary sodium and animal protein intake. Two groups were farmers from Shanxi in northern China, and Guangxi in southern China, and the third were fishermen from Zhejiang, eastern China. Three 24-hour dietary recalls were done for each participant. Serum and overnight urine amino acids were measured in random subsamples. Determination of electrolytes in three 24-hour urine specimens was done in an additional sample of 59 men in each population. Results of multiple or stepwise regression showed: 1) in the pooled group, individual intake of sodium was positively associated with systolic blood pressure; 2) when stratifying by median calcium intake, a positive association of dietary sodium or sodium/potassium was found only in the group with calcium intake lower than the median; 3) daily intake of animal protein, urinary sulphate and certain serum and urine amino acids formed from protein metabolism, were inversely associated with blood pressure.

Membrane association of phospholipase C encoded by the norpA gene of Drosophila melanogaster

Severe mutations within the norpA gene of Drosophila abolish the photoreceptor potential and render the fly blind by deleting phospholipase C, an essential component of the phototransduction pathway. To study the membrane association of phospholipase C, we have utilized biochemical assays of phospholipase C activity, which predominant measurable phospholipase C activity in head homogenates has been shown to be encoded by norpA, as well as antisera generated against the major gene product of norpA to examine its subcellular distribution before and during phototransduction. We find that both phospholipase C activity and the norpA protein are predominantly associated with membrane fractions in heads of both light- and dark-adapted flies. Moreover, phospholipase C activity as well as norpA protein can be easily extracted from membrane preparations of light- or dark-adapted flies using high salt, indicating that the norpA protein is peripherally localized on the membrane. These data suggest that the norpA encoded phospholipase C of Drosophila is a permanent peripheral membrane protein. If this is indeed the case, then it would mean that the reversible redistribution of phospholipase C from the cytosol to the membrane, as observed in epidermal growth factor receptor stimulation of mammalian phospholipase C gamma, is not a universal mechanism utilized by all types of phosphatidylinositol-specific phospholipase C.

Serum-induced vascular smooth muscle cell elastolytic activity through tyrosine kinase intracellular signalling

In previous studies, we related increased elastolytic activity in pulmonary arteries (PA) with endothelial injury to the later development of PA hypertension in rats. As the mechanism causing the increased PA elastase was unknown, we hypothesized that serum factors which are accessible to vascular smooth muscle cells (SMC) following endothelial injury stimulate their elastolytic activity. To test this, we developed an in vitro assay in which we added [3H]-elastin to cultured vascular SMC after 24 h serum starvation and monitored elastolysis following a further 24 h incubation with fetal bovine serum (FBS). We observed that serum induced increased elastolytic activity in both PA and aorta-derived SMC but not in endothelial cells or SMC with low basal levels of elastolytic activity. Maximum stimulation of SMC elastolytic activity occurred with a concentration as low as 1% FBS and despite elastase inhibitors in serum, suggesting that the activity is confined to the immediate pericellular region where enzyme concentration is high. Serum-stimulated elastolytic activity was not reproduced by growth factors or cytokines known to be associated with vascular disease or to induce release of elastases in other cells. The serum inducing elastolytic activity was heat and acid labile. It was associated with increased elastin adhesion to the 67 kD elastin binding protein on SMC surfaces and was prevented by tyrosine kinase inhibitors but not protein kinase C or A inhibitors. Our studies therefore suggest a mechanism whereby serum induction of SMC elastase requires signalling through the elastin binding protein and activation of tyrosine kinase.

Reversal of terminal differentiation mediated by p107 in Rb-/- muscle cells

The terminal differentiation of mammalian muscle cells requires the tumor suppressor retinoblastoma protein (Rb). Unlike their wild-type counterparts, multinucleated myotubes from mouse cells deficient in Rb (Rb-/-) were induced by serum to re-enter the cell cycle. Development of the myogenic phenotype in Rb-/- cells correlated with increased expression of p107, which interacted with myogenic transcription factors. Serum-induced cell cycle reentry, on the other hand, correlated with decreased p107 expression. Thus, although p107 could substitute for Rb as a cofactor for differentiation, it could not maintain the terminally differentiated state in Rb-/- myotubes.

Structure and expression of the human slow twitch skeletal muscle troponin I gene

The contractile protein troponin I is encoded by a multigene family whose members are expressed differentially in various classes of muscle fibers. In vertebrates, the "slow" isoform of troponin I is expressed during early heart and skeletal muscle development but is restricted to slow twitch skeletal muscle in the adult. This diverse expression pattern offers an opportunity to study the regulation of a single gene within different developmental contexts. To initiate such studies, we have cloned the gene encoding the human slow twitch skeletal muscle isoform of troponin I and have identified 5'-flanking sequences required for its expression in skeletal muscle cells. The slow troponin I gene spans 12.5 kilobases and is divided into nine exons. In contrast to many muscle-specific genes, the troponin I promoter does not contain consensus CCAAT or TATA elements. Moreover, the sequence from -9 to +11 resembles an "initiator element" previously shown to direct transcription of some tissue-specific genes lacking TATA boxes (Smale, S. T., and Baltimore, D. (1989) Cell 57, 103-113; Brand, N. J., Petkovich, M., and Chambon, P. (1990) Nucleic Acids Res. 18, 6799-6806; Weis, L., and Reinberg, D. (1992) FASEB J. 6, 3300-3309). A transcriptional fusion construct, comprising 4.2 kilobases of troponin I 5'-flanking DNA linked to the bacterial chloramphenicol acetyl-transferase gene, exhibited cell type-specific and developmentally regulated expression. A muscle-specific enhancer regulated slow troponin I promoter activity.

Sequencing of a cDNA encoding the human fast-twitch skeletal muscle isoform of troponin I

A cDNA encoding the human fast-twitch skeletal muscle isoform of troponin I (TnIfast) has been sequenced. This cDNA is 701 base pairs in length, and encodes a protein of 182 amino acids. TnIfast is the last of the three known human TnI isoforms to be sequenced. Comparison of the deduced human TnIfast protein sequence with a variety of troponin I isoforms from other species has revealed a high degree of cross-species sequence conservation between TnIfast proteins.

Posttranscriptional effector domains in the Rev proteins of feline immunodeficiency virus and equine infectious anemia virus

By systematically dissecting the Rev proteins of feline immunodeficiency virus (FIV) and equine infectious anemia virus (EIAV), we have identified within each a short peptide that is functionally interchangeable with the effector domains found in Rev-like proteins from other retroviruses. The active sequences from FIV and EIAV differ in several respects from other known effectors and may represent a distinct class of effector domain.

Quantitative structural comparisons of heme protein crystals and solutions using resonance Raman spectroscopy

Resonance Raman difference spectra have been used to compare crystal and solution samples of metmyoglobin (metMb), deoxymyoglobin (deoxyMb), and cytochrome P450. At pH 6.0, the frequency shifts of the heme core size sensitive bands v2, v3, and v4 were determined to be less than 0.3, 1.0, and 0.3 cm-1, respectively, for metMb and to be less than 1.0, 1.0, and 0.3 cm-1, respectively, for deoxyMb. This shows that the heme core size differences between the crystal and solution conformations are less than 0.002 A for metMb and less than 0.003 A for deoxyMb. These results disagree with a recent extended X-ray absorption fine structure study [Zhang, K., Chance, B., Reddy, K. S., Ayene, I., Stern, E. A., & Bunker, G. (1991) Biochemistry 30, 9116-9120] which claims that a 0.05-A difference exists in the average iron-ligand distance between the crystalline and solution forms of metMb at pH 6.5. At pH 8.5, metMb solution samples change gradually from a predominantly high-spin to a predominantly low-spin species as the ammonium sulfate concentration is increased to the level found in the crystal mother liquor. No Raman frequency shifts are found between the crystal and solution forms of metMb at pH 8.5 when the ammonium sulfate concentrations are equal. On the other hand, for deoxyMb, we find a significant alteration in the 220/240-cm-1 line shape and relative intensities, suggesting that some histidine-heme perturbation takes place upon crystallization.(ABSTRACT TRUNCATED AT 250 WORDS)

[Gastric mucosal blood flow and blood viscosity in patients with diabetes]

For the study of the microcirculatory disturbance of the digestive tract in patients with diabetes, 41 cases with non-insulin dependent diabetes mellitus (NIDDM) were selected (mean age 53.9 Yrs., 22 male/19 female). Of these patients 9 were without complication, and 32 with complications. Gastric mucosal blood flow (GMBF) was determined at 14 points of laser and greater curvature, anterior and posterior wall of antrum, angle and corpus of stomach, pylorus and anterior wall of duodenum with laser Doppler flowmetry (PF2). Results showed that the mean value of the 14 points of GMBF in 41 patients with NIDDM was 2.81 +/- 0.15(V, mean +/- s mean), which was significantly lower than that of 11 normal subjects (4.77 +/- 0.29V, P < 0.001). The mean GMBF of 8 cases of NIDDM without gastric disease was 2.92 +/- 0.28V, which was also lower than that of normal control (61.2% of normal value, P < 0.001). The GMBF in 27 cases of diagnosed chronic superficial gastritis (CSG 2.79 +/- 0.15V) was lower than the GMBF of 63 CSG patients without NIDDM (3.23 +/- 0.12V, P < 0.05). The viscosity of blood and plasma was determined with NAAKE viscometer in 26 patients with NIDDM. It was found that the blood viscosity was significantly higher than that of the normal control, and the plasma viscosity was also increased but without statistic significance. Results showed that the GMBF of NIDDM was significantly lower than that of the normal subjects or CSG patients without diabetes. It implied that the visceral microcirculatory disturbance also involved the digestive system leading to the GMBF decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue-specific expression of phospholipase C encoded by the norpA gene of Drosophila melanogaster

Mutations in the norpA gene of Drosophila melanogaster severely affect the light-evoked photoreceptor potential with strong mutations rendering the fly blind. Molecular cloning of the norpA gene revealed that it encodes phosphatidylinositol-specific phospholipase C, which enzymes play a pivotal role in one of the largest classes of signaling pathways known. We have used Northern analysis, Western blots, phospholipase C activity assays, and immunohistochemical staining of tissues to examine the tissue-specific expression of the norpA gene and found that it is expressed in a variety of tissues besides the eye. Hybridization of norpA cRNA probe to blots of poly(A+) RNA reveals that the gene encodes at least four transcripts: a 7.5-kilobase (kb) transcript that is expressed in eye and 6.5-, 5.5-, and 5.0-kb transcripts that are expressed in adult body or early stages of development. Antiserum generated against the major gene product of norpA recognizes a 130-kDa protein that is abundant in eyes but severely reduced or absent in norpA mutants, a result which is consistent with previous conclusions that the norpA gene encodes an essential component of the visual system. However, the norpA antiserum also recognizes a 130-kDa protein in adult legs, thorax, and male abdomen, but not female abdomen. These localizations are supported by results of phospholipase C activity assays which show that the norpA mutation reduces phospholipase C activity in each of the tissues in which norpA protein can be detected. Furthermore, immunohistochemical staining of tissue sections with the norpA antiserum demonstrates that the norpA protein is abundant in the retina and ocelli and is present to a lesser extent in the brain and thoracic nervous system. Since some of the above mentioned tissues that express norpA (such as thorax, legs, and abdomen) have no known photoreceptor tissue, we conclude that the norpA gene product is also likely to have a role in signaling pathways other than phototransduction.

Tissue tolerance to pelvic intraarterial chemoembolization with cisplatin-lipiodol suspension

Tissue tolerance to pelvic intraarterial chemoembolization with cisplatin-lipiodol suspension was studied in rabbits. Cisplatin (3 mg/kg) was used with different doses of lipiodol (0.0, 0.1, 0.2, and 0.3 ml/kg). Cisplatin-lipiodol suspension was injected into the umbilical artery through a long polyethylene catheter. Local tissue concentration of platinum was increased with lipiodol, while that in the liver, heart, and kidneys was reduced. Tissue retention of platinum was linearly related to the dosage of lipiodol. With a single dose of 0.2 ml/kg lipiodol, only slight degeneration and sparse hemorrhage were observed without necrosis.

Inhibition of cell proliferation by p107, a relative of the retinoblastoma protein

The cellular protein p107 shares many structural and biochemical features with the retinoblastoma gene product, pRB. We have isolated a full-length cDNA for human p107 and have used this clone to study the function of p107. We show that, like pRB, p107 is a potent inhibitor of E2F-mediated trans-activation, and overexpression of p107 can inhibit proliferation in certain cell types, arresting sensitive cells in G1. Several experiments, however, showed that growth inhibition by pRB and p107 did not occur through the same mechanism. First, in the cervical carcinoma cell line C33A, p107 was able to block cell proliferation, whereas pRB could not, even though both proteins were potent inhibitors of E2F-mediated transcription in this cell line. Second, growth arrest by pRB and p107 was rescued differentially by various cell cycle regulators. Third, some mutants of p107 that cannot associate with adenovirus E1A were still able to inhibit cell proliferation, whereas analogous mutants in pRB are known to be unable to block cell growth. Together, these results suggest a biological role of p107 that is related, but not identical, to that of pRB.

[Distribution of the intermediate filaments in rat Sertoli cells: an electron microscopic study]

The distribution of intermediate filaments (IFs) in the Sertoli cells of rat testis was studied under a transmission electron microscope. The results showed that IFs in Sertoli cells were centrally arranged around the nucleus in a criss-cross manner. From the perinuclear region the IFs had widespread extensions and were connected with the following structures: 1) with the mitochondria, Golgi apparatus, endoplasmic reticulum and other subcellular structures; 2) with the desmosome-like and hemi-desmosome-like junctions with adjacent Sertoli and spermatogenic cells; 3) with the microfilaments (MFs) in the ectoplasmic specialization (ES) surrounding the head of elongated stage I-V; spermatids; 4) with the MFs in ES between adjacent Sertoli cells. In conclusion, IFs form a delicate intracellular network in Sertoli cell with its center in the perinuclear region and stretching and connecting with many subcellular structures in the cytoplasm and cell membrane.

A developmentally regulated program restricting insolubilization of elastin and formation of laminae in the fetal lamb ductus arteriosus

BACKGROUND

The ductus arteriosus (DA) is a fetal vessel in which the elastic laminae fail to assemble normally in late gestation. This feature is associated with the development of intimal cushions, structures that partially occlude the DA lumen and assure that the vessel will close completely when it constricts postnatally.

EXPERIMENTAL DESIGN

We studied the fetal lamb DA at two different gestational time-points, 100 days before, and 138 days coincident with intimal cushion formation (term = 145 days) to establish the ultrastructural basis for the 'disassembly' of elastic laminae apparent on light microscopy and to determine further whether the mechanism was due to increased elastolytic activity, decreased synthesis of tropoelastin, or impaired insolubilization of tropoelastin.

RESULTS

Morphometric ultrastructural analyses of tissue from the 138-day gestation fetal lambs revealed that the volume density of elastin in the DA vessel wall was only 40% of that in the aorta (Ao) and 50% of that in the pulmonary artery (PA). Moreover, only 16% of the elastin present contributed to the formation of laminae when compared to 80% in the Ao and 50% in the PA. Despite the morphologic appearance of 'fragmented' elastin, there was no evidence of increased elastolytic activity in the DA at either gestational time-point as judged by solubilization of a [3H] elastin substrate. The reduced elastin apparent was morphologically accompanied by an increase in soluble (tropo) elastin in DA compared with Ao and PA, as measured by enzyme linked immunosorbent assay, in tissue from both 100- and 138-day gestation lambs. Lack of differences in tropoelastin mRNA levels when comparing the 3 vessels suggested that the enzyme linked immunosorbent assay measurements reflected increased DA tropoelastin accumulation owing to lack of insolubilization rather than an increase in synthesis. Reduced insolubilization of newly synthesized elastin was evident in the DA compared with the Ao at 100 days gestation and in the DA compared with both Ao and PA at 138 days gestation in association with reduced desmosine levels.

CONCLUSIONS

The mechanism of the decrease in tropoelastin insolubilization was unrelated to lysyl oxidase activity in the tissue and represents a unique developmental program.

[Typing on 5'-terminal noncoding region of hepatitis C virus genome with restrict endonuclease]

We reported typing of the 5'-terminal noncoding region of HepCV genome in 219 patients with hepatitis C using restrict endonuclease. These patients came from different areas of China. The infective percentage of HCV type II was 83%, type III 14%, and mixed type II and III (II/III) 2%. It is indicated that type III and II/III. The constituent rate of HCV subgenome type in different areas was not significantly different.

Aging changes in the beta-endorphin neuronal system in the preoptic area of the C57BL/6J mouse: ultrastructural analysis

In hypothalami of aging rodents, beta-endorphin (beta-EP) neuron number and content are reduced. The objectives of this study were: first, to analyze ultrastructurally the population of neuronal elements in a selected region of the preoptic area (POA) in young and old mice; second, to study the beta-EP neuronal system in the same region to determine whether or not this population remains stable with age. Vibratome sections from the most caudal POA through the diagonal band of Broca were examined by light microscopy and immunocytochemistry in mature, cycling (5-6 months old) and old, acyclic, disease-free (24-26 months old) mice. A subset of beta-EP-like perikarya and associated structures was observed in the periventricular POA. When this subregion was examined at the ultrastructural level, there was a significant decrease in the number of recipient dendrites [3.78 +/- 0.04 SEM/micron 2 young vs. 0.82 +/- 0.03/micron 2 old; p < 0.007, analysis of variance (ANOVA)], but a significant increase in the number of nonmyelinated axons (20.0 +/- 2.6/micron 2 young vs. 26.8 +/- 0.7/micron 2 old; p < 0.05). Immunolabeled terminals that contained a synapse comprised 2.56 +/- 0.08% of all terminals with synapses in young mice but only 0.34 +/- 0.04% in old ones when corrected for surface area examined (p < 0.03). A significant age-related loss was also observed in the nonmyelinated beta-EP-labeled axon population (1.50 +/- 0.10% young vs. 0.40 +/- 0.01% old; p < 0.009, ANOVA). We conclude that there are critical changes in the microenvironment of the POA in old, noncycling female mice that are likely to affect neuron function.

Synthesis and cytotoxic evaluation of some 6-arylidene-2-(alpha-hydroxyamino-alpha-arylmethyl)cyclohexanone oximes and related compounds

Reaction of 2,6-bis-(phenylmethylene)cyclohexanone (1) with a 4-molar excess of hydroxylamine hydrochloride and sodium acetate to produce the corresponding oxime 2 gave rise to 2-(alpha-hydroxyamino-alpha-phenylmethyl)-6-phenylmethylenecyclohexan one oxime (5a), whose structure was deduced from high-resolution proton nuclear magnetic resonance spectroscopy and confirmed by X-ray analysis. Compound 2 was eventually prepared from 1 with hydroxylamine per se and not with a mixture of hydroxylamine hydrochloride and sodium acetate. Ten analogues of 5a, namely 5b-5k, were prepared and evaluated for cytotoxicity. Six of the 11 compounds in series 5, as well as 1, showed activity in the 240-950 microM range against murine mammary EMT6 cells. Series 5 was also examined for cytotoxicity in an in vitro screen conducted by the National Cancer Institute with approximately 54 cell lines, and four compounds demonstrated selective toxicity toward various groups of tumors.

Albumin in the cornea is oxidized by hydrogen peroxide

The action of hydrogen peroxide on soluble proteins of the rat cornea has been evaluated. Two major corneal proteins are found to be oxidized by 10 mM hydrogen peroxide. Protein sequence and antibody recognition has shown one of the proteins to be albumin. Treatment of pure rat or human albumin with hydrogen peroxide oxidizes the protein and decreases its affinity for its antibody. Because albumin is a major protein in the cornea, its ready oxidation suggests that a role for albumin in this tissue may be to act as a native antioxidant, scavenging hydrogen peroxide and thus preventing more extensive damage by this toxin. These data are relevant to the evaluation of the safety of contact lens disinfectants containing hydrogen peroxide and suggest that further study of the action of this oxidant is warranted.

Functional organization of enhancer (ENII) of hepatitis B virus

A new enhancer ENII, located in the X open reading frame and immediately upstream of the core gene promoter, has recently been identified in the genome of hepatitis B virus. We have studied the functional constituents of this new enhancer in different cell lines. ENII can be divided into two functional elements, A and B, corresponding to two major binding sequences for nuclear protein factors. Element A alone gave very low activity; however, it was a modulatory element important for cell-type specificity. Element B was shown to be the basic functional element of ENII, which retained about 70% of the enhancer activity of the complete ENII in HepG2 cells. Element B can be further dissected into three subunits, B1, B2, and B3, which act synergistically. A 52-bp sequence is identified as the core sequences of element B. A model for the mechanism of ENII function is proposed.

Bactericidal activity of peroxynitrite

Peroxynitrite is a strong oxidant formed by macrophages and potentially by other cells that produce nitric oxide and superoxide. Peroxynitrite was highly bactericidal, killing Escherichia coli in direct proportion to its concentration with an LD50 of 250 microM at 37 degrees C in potassium phosphate, pH 7.4. The apparent bactericidal activity of a given concentration peroxynitrite at acidic pH was less than that at neutral and alkaline pH. However, after taking the rapid pH-dependent decomposition of peroxynitrite into account, the rate of the killing was not significantly different at pH 5 compared to pH 7.4. Metal chelators did not decrease peroxynitrite-mediated killing, indicating that exogenous transition metals were not required for toxicity. The hydroxyl radical scavengers mannitol, ethanol, and benzoate did not significantly affect toxicity while dimethyl sulfoxide enhanced peroxynitrite-mediated killing. Dimethyl sulfoxide is a more efficient hydroxyl radical scavenger than the other three scavengers and increased the formation of nitrogen dioxide from peroxynitrite. In the presence of 100 mM dimethyl sulfoxide, 60.0 +/- 0.3 microM nitrogen dioxide was formed from 250 microM peroxynitrite as compared to 2.0 +/- 0.1 microM in buffer alone. Thus, formation of nitrogen dioxide may have enhanced the toxicity of peroxynitrite decomposing in the presence of dimethyl sulfoxide.

Peroxynitrite formation from macrophage-derived nitric oxide

Peroxynitrite formation by rat alveolar macrophages activated with phorbol 12-myristate 13-acetate was assayed by the Cu,Zn superoxide dismutase-catalyzed nitration of 4-hydroxyphenylacetate. The inhibitor of nitric oxide synthesis N-methyl-L-arginine prevented the Cu,Zn superoxide dismutase-catalyzed nitration of 4-hydroxyphenylacetate by stimulated macrophages, while Cu-depleted Zn superoxide dismutase did not catalyze the formation of 3-nitro-4-hydroxyphenylacetate either in vitro or in the presence of activated macrophages. The rate of phenolic nitration by activated macrophages was 9 +/- 2 pmol x 10(6) cells-1 x min-1 (mean +/- STD). Only 8% of synthetic peroxynitrite was trapped by superoxide dismutase, which suggested that the rate of peroxynitrite formation may have been as high as 0.11 nmol x 10(6) cells-1 x min-1. This upper estimate was consistent with N-methyl-L-arginine increasing the amount of superoxide detected with cytochrome c by 0.12 nmol x 10(6) cells-1 x min-1. The rate of nitrite and nitrate accumulation was 0.10 +/- 0.001 nmol x 10(6) cells-1 x min-1, suggesting that the majority of nitric oxide produced by activated macrophages may have been converted to peroxynitrite. The formation of a relatively long lived, strong oxidant from the reaction of nitric oxide and superoxide in activated macrophages may contribute to inflammatory cell-mediated tissue injury.

Kinetics of superoxide dismutase- and iron-catalyzed nitration of phenolics by peroxynitrite

Superoxide dismutase and Fe3+EDTA catalyzed the nitration by peroxynitrite (ONOO-) of a wide range of phenolics including tyrosine in proteins. Nitration was not mediated by a free radical mechanism because hydroxyl radical scavengers did not reduce either superoxide dismutase or Fe3+EDTA-catalyzed nitration and nitrogen dioxide was not a significant product from either catalyst. Rather, metal ions appear to catalyze the heterolytic cleavage of peroxynitrite to form a nitronium-like species (NO2+). The calculated energy for separating peroxynitrous acid into hydroxide ion and nitronium ion is 13 kcal.mol-1 at pH 7.0. Fe3+EDTA catalyzed nitration with an activation energy of 12 kcal.mol-1 at a rate of 5700 M-1.s-1 at 37 degrees C and pH 7.5. The reaction rate of peroxynitrite with bovine Cu,Zn superoxide dismutase was 10(5) M-1.s-1 at low superoxide dismutase concentrations, but the rate of nitration became independent of superoxide dismutase concentration above 10 microM with only 9% of added peroxynitrite yielding nitrophenol. We propose that peroxynitrite anion is more stable in the cis conformation, whereas only a higher energy species in the trans conformation can fit in the active site of Cu,Zn superoxide dismutase. At high superoxide dismutase concentrations, phenolic nitration may be limited by the rate of isomerization from the cis to trans conformations of peroxynitrite as well as by competing pathways for peroxynitrite decomposition. In contrast, Fe3+EDTA appears to react directly with the cis anion, resulting in greater nitration yields.

Peroxynitrite-mediated tyrosine nitration catalyzed by superoxide dismutase

Peroxynitrite (ONOO-), the reaction product of superoxide (O2-) and nitric oxide (NO), may be a major cytotoxic agent produced during inflammation, sepsis, and ischemia/reperfusion. Bovine Cu,Zn superoxide dismutase reacted with peroxynitrite to form a stable yellow protein-bound adduct identified as nitrotyrosine. The uv-visible spectrum of the peroxynitrite-modified superoxide dismutase was highly pH dependent, exhibiting a peak at 438 nm at alkaline pH that shifts to 356 nm at acidic pH. An equivalent uv-visible spectrum was obtained by Cu,Zn superoxide dismutase treated with tetranitromethane. The Raman spectrum of authentic nitrotyrosine was contained in the spectrum of peroxynitrite-modified Cu,Zn superoxide dismutase. The reaction was specific for peroxynitrite because no significant amounts of nitrotyrosine were formed with nitric oxide (NO), nitrogen dioxide (NO2), nitrite (NO2-), or nitrate (NO3-). Removal of the copper from the Cu,Zn superoxide dismutase prevented formation of nitrotyrosine by peroxynitrite. The mechanism appears to involve peroxynitrite initially reacting with the active site copper to form an intermediate with the reactivity of nitronium ion (NO2+), which then nitrates tyrosine on a second molecule of superoxide dismutase. In the absence of exogenous phenolics, the rate of nitration of tyrosine followed second-order kinetics with respect to Cu,Zn superoxide dismutase concentration, proceeding at a rate of 1.0 +/- 0.1 M-1.s-1. Peroxynitrite-mediated nitration of tyrosine was also observed with the Mn and Fe superoxide dismutases as well as other copper-containing proteins.

The Escherichia coli rna gene encoding RNase I: sequence and unusual promoter structure

A clone containing the Escherichia coli rna gene encoding the nonspecific endoribonuclease, RNase I, was isolated and sequenced. The sequence of the 1070-nucleotide (nt) fragment agreed completely with that of a rna clone recently reported by Meador and Kennell [Gene 95 (1990) 1-7]. The transcription start point (tsp) of rna was identified using primer extension analysis, and its promoter sequence was established by comparison of RNase I expression levels in various deletion mutants. Our results indicate that the rna promoter is highly unusual. Its -35 region shows a poor match to the consensus sequence, and moreover, it is located within a stem-loop structure that apparently is a Rho-independent transcription termination site for an upstream gene.

Clinical and experimental studies on tong yu ling in the treatment of diabetic hyperlipemia

72 diabetes mellitus patients (70 cases non-insulin-dependent) were treated routinely with D860. After one month, cases with persisting hyperglycemia and hyperlipemia were randomly divided into Group A to be treated with D860 plus Tong Yu Ling (TYL), and Group B to continue treatment with D860 alone, while Group C, comprising cases with persisting hyperlipemia only, were treated with TYL alone. Therapeutic results showed that of the total 50 cases of Group A and C, 26 were markedly improved, 14 improved, and 10 cases ineffective. The antihyperlipemic effect was pronounced in Group A, where the blood cholesterol, beta-lipoprotein and triglyceride showed remarkable decline, less pronounced in Group C, and insignificant in Group B. Experiments in rat models of non-insulin-dependent diabetes demonstrated that TYL was markedly effective in treating hyperlipemia.

Human erythrocyte protein 4.2: isoform expression, differential splicing, and chromosomal assignment

Human protein 4.2 (P4.2) is a major membrane skeletal protein in erythrocytes. Individuals with P4.2 deficiency exhibit spherocytosis and experience various degrees of hemolytic anemia, suggesting a role for this protein in maintaining stability and integrity of the membrane. Molecular cloning of P4.2 cDNAs showed that P4.2 is a transglutaminaselike molecule in erythrocytes but lacks the essential cysteine for cross-linking activity. Two cDNA isoforms have been identified from a human reticulocyte cDNA library, with the long isoform containing a 90-base pair (bp) in-frame insertion encoding an extra 30 amino acids near the N-terminus. Characterization of the P4.2 gene suggests differential splicing as the mechanism for generating these two cDNA isoforms. The donor site for the short isoform (P4.2S) agrees better with the consensus than the donor site for the long isoform (P4.2L) does. Expression of P4.2L was detected by a long-isoform-specific antibody raised against a peptide within the 30-amino acid insert. Western blot analyses showed P4.2L to be a minor membrane skeletal protein in human erythrocytes with an apparent molecular weight (mol wt) of approximately 3 Kd larger than the major protein 4.2, P4.2S. By in situ hybridization of a full-length 2.4-kilobase (kb) cDNA to human metaphase chromosomes, the gene for P4.2 was mapped to bands q15-q21 of chromosome 15, and it is not linked to the gene for coagulation factor XIIIa (plasma transglutaminase, TGase).