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Biomedical subjects

S Hattori

Publications and source records attributed to S Hattori.

At least 19 recordsLinked to original sources

An abnormal fibrinogen Fukuoka II (Gly-B beta 15-->Cys) characterized by defective fibrin lateral association and mixed disulfide formation.

A dysfibrinogenemia was attributable to a single amino acid substitution from glycine to cysteine at residue 15 of the B beta chain in a fibrinogen molecule designated as fibrinogen Fukuoka II. The fibrinogen Fukuoka II showed prolonged thrombin and reptilase times and impaired fibrinopeptide B release by thrombin, resulting in abolition of fibrin monomer repolymerization under physiological conditions. Repolymerization of the des-(B beta 1-42)-fibrin monomers, however, was not distinguished from the normal pattern of des-(B beta 1-42)-fibrin monomers, suggesting that no other abnormality existed in fibrinogen Fukuoka II. Although an additional cysteine was substituted at residue 15 of the B beta chain, fibrinogen Fukuoka II had no free sulfhydryl group within the molecule. Instead, fibrinogen Fukuoka II formed a disulfide bond with cysteine, albumin, another mutated B beta chain within the same molecule, or intermolecular dimeric fibrinogen Fukuoka II. The mutation in fibrinogen Fukuoka II was the same as that in fibrinogen Ise published previously (Yoshida, N., Wada, H., Morita, K., Hirata, H., Matsuda, M., Yamazumi, K., Asakura, S., and Shirakawa, S. (1991) Blood 77, 1958-1963). Fibrinogen Ise, however, has been described as having prolonged thrombin time but normal reptilase time. Reasons for the discrepancy were not clear. Analysis of the B beta 1-42 fragment showed that fibrinogen was heterogeneous at position 31 of the B beta chain with respect to proline or hydroxyproline.

Amino Acid Sequence

Requirement of Saccharomyces cerevisiae Ras for completion of mitosis.

In the yeast Saccharomyces cerevisiae, Ras regulates adenylate cyclase, which is essential for progression through the G1 phase of the cell cycle. However, even when the adenosine 3',5'-monophosphate (cAMP) pathway was bypassed, the double disruption of RAS1 and RAS2 resulted in defects in growth at both low and high temperatures. Furthermore, the simultaneous disruption of RAS1, RAS2, and the RAS-related gene RSR1 was lethal at any temperature. The triple-disrupted cells were arrested late in the mitotic (M) phase, which was accompanied by an accumulation of cells with divided chromosomes and sustained histone H1 kinase activity. The lethality of the triple disruption was suppressed by the multicopies of CDC5, CDC15, DBF2, SPO12, and TEM1, all of which function in the completion of the M phase. Mammalian ras also suppressed the lethality, which suggests that a similar signaling pathway exists in higher eukaryotes. These results demonstrate that S. cerevisiae Ras functions in the completion of the M phase in a manner independent of the Ras-cAMP pathway.

Adenylyl Cyclases

Induction of neurite outgrowth by MAP kinase in PC12 cells.

Treatment of PC12 cells with nerve growth factor (NGF) results in neural differentiation of the cells, inducing neurite outgrowth. Ras protein has been shown to play an essential role in this process. To examine whether or not the MAP kinase (MAPK) cascade mediates the NGF- and Ras-induced neural differentiation process, we injected PC12 cells with constitutive active forms of each components of the MAPK cascade. When a moderately active mutant of Xenopus MAPK kinase (S222E-MAPKK) in which Ser 222 was changed into glutamic acid was injected, the neurite outgrowth of PC12 cells occurred to some extent. Injection of an N-terminal truncated STE11 protein (delta N-STE11), a constitutively active form of STE11 which is a yeast MAPKK kinase, induced neurite outgrowth in PC12 cells. Furthermore, injection of thiophosphorylated MAPK, but not purified active MAPK, into PC12 cells resulted in neurite outgrowth. Thiophosphorylated MAPK was resistant to protein phosphatase 2A treatment, while purified active MAPK was inactivated by this treatment. All these results have suggested that sustained activation of MAPK is sufficient for PC12 cell differentiation. In accord with this, the delta N-STE11- or S222E- MAPKK-induced neurite outgrowth was inhibited by coinjection of CL-100 protein, a dual-specificity phosphatase that is capable of inactivating MAPK.

Animals

Accelerated evolution in the protein-coding regions is universal in crotalinae snake venom gland phospholipase A2 isozyme genes.

The nucleotide sequences of four genes encoding Trimeresurus gramineus (green habu snake, crotalinae) venom gland phospholipase A2 (PLA2; phosphatidylcholine 2-acylhydrolase, EC 3.1.1.4) isozymes were compared internally and externally with those of six genes encoding Trimeresurus flavoviridis (habu snake, crotalinae) venom gland PLA2 isozymes. The numbers of nucleotide substitutions per site (KN) for the noncoding regions including introns were one-third to one-eighth of the numbers of nucleotide substitutions per synonymous site (KS) for the protein-coding regions of exons, indicating that the noncoding regions are much more conserved than the protein-coding regions. The KN values for the introns were found to be nearly equivalent to those of introns of T. gramineus and T. flavoviridis TATA box-binding protein genes, which are assumed to be a general (nonvenomous) gene. Thus, it is evident that the introns of venom gland PLA2 isozyme genes have evolved at a similar rate to those of nonvenomous genes. The numbers of nucleotide substitutions per nonsynonymous site (KA) were close to or larger than the KS values for the protein-coding regions in venom gland PLA2 isozyme genes. All of the data combined reveal that Darwinian-type accelerated evolution has universally occurred only in the protein-coding regions of crotalinae snake venom PLA2 isozyme genes.

Amino Acid Sequence

A constitutive effector region on the C-terminal side of switch I of the Ras protein.

The "switch I" region (Asp30-Asp38) of the Ras protein takes remarkably different conformations between the GDP- and GTP-bound forms and coincides with the so-called "effector region." As for a region on the C-terminal side of switch I, the V45E and G48C mutants of Ras failed to promote neurite outgrowth of PC12 cells (Fujita-Yoshigaki, J., Shirouzu, M., Koide, H., Nishimura, S., and Yokoyama, S. (1991) FEBS Lett. 294, 187-190). In the present study, we performed alanine-scanning mutagenesis within the region Lys42-Ile55 of Ras and found that the K42A, I46A, G48A, E49A, and L53A mutations significantly reduced the neurite-inducing activity. This is an effector region by definition, but its conformation is known to be unaffected by GDP-->GTP exchange. So, this region is referred to as a "constitutive" effector (Ec) region, distinguished from switch I, a "switch" effector (Es) region. The Ec region mutants exhibiting no neurite-inducing activity were found to be correlatably unable to activate mitogen-activated protein (MAP) kinase in PC12 cells. Therefore, the Ec region is essential for the MAP kinase activation in PC12 cells, whereas mutations in this region only negligibly affect the binding of Ras to Raf-1 (Shirouzu, M., Koide, H., Fujita-Yoshigaki, J., Oshio, H., Toyama, Y., Yamasaki, K., Fuhrman, S. A., Villafranca, E., Kaziro, Y., and Yokoyama, S. (1994) Oncogene 9, 2153-2157).

Animals

Structures of genes encoding TATA box-binding proteins from Trimeresurus gramineus and T. flavoviridis snakes.

A cDNA encoding the Trimeresurus gramineus (Tg; green habu snake) TATA-box-binding protein (TgTBP) was cloned and sequenced. The cDNA encodes a 33-kDa protein with an extensive sequence similarity to those derived from other organisms, except for the N-terminal domain. Genes encoding TgTBP and Trimeresurus flavoviridis (Tf; habu snake) TBP (TfTBP) were isolated using a TgTBP cDNA and their nt sequences were determined. They are the first TBP genes entirely sequenced in higher animals. Both genes span over 15 kb and are constructed from eight exons and seven introns. Comparison of the loci of introns on the aligned amino-acid sequences of TBP from six organisms (Tg, Tf, mouse, Arabidopsis thaliana, Schizosaccharomyces pombe and Acanthamoeba castellanii) indicated that there are three highly conserved loci in the C-terminal domain.

Amino Acid Sequence

[The synergistic effect of interferon-gamma on the induction of nitric oxide synthase by lipopolysaccharide in vascular smooth muscle].

Bacterial lipopolysaccharide (LPS) and other immunostimulants induce an isoform of nitric oxide synthase (iNOS) in vascular smooth muscle (VSM) which produces large quantities of nitric oxide (NO) and profound vasodilation. This process has been implicated as the cause of gram-negative septic shock. It has been demonstrated that interferon-gamma (IFN) markedly potentiates cytokine-induced NO synthesis in various cell types. However, little is known about the mechanism of this enhancing effect of IFN. The present study was undertaken to investigate the effect of IFN on LPS-induced NO synthesis and iNOS mRNA expression in VSM and the possibility of nuclear factor kB (NFkB) involvement in the effect of IFN. LPS-induced NO synthesis is markedly potentiated by IFN in VSM. Expression of iNOS mRNA in VSM costimulated with IFN and LPS was greatly increased compared to that induced by LPS alone. IFN did not alter the lifetime of iNOS mRNA. LPS stimulated translocation into the nuclei of NFkB which is believed to play an important role in the induction of iNOS, but IFN did not enhance NFkB activation by LPS. These results suggest that the enhancing effect of IFN is due to the increased transcription of the iNOS gene rather than a decreased degradation of iNOS mRNA and that the NFkB activation pathway is not involved in this effect of IFN.

Amino Acid Oxidoreductases

The herbal medicine sho-saiko-to induces nitric oxide synthase in rat hepatocytes.

We have examined the effects of the herbal medicine sho-saiko-to (SST) on nitric oxide (NO) biosynthesis in rat hepatocytes by measuring the stable end-product nitrite and the mRNA of inducible NO synthase (iNOS). Interferon-gamma (IFN) by itself failed to induce NO synthesis (IFN: 1-1,000 u/ml). SST also did not elicit NO synthesis at concentrations up to 300 micrograms/ml when administered alone, but dose-dependently induced NO production in the presence of IFN. Whereas SST or IFN induced barely detectable levels of iNOS mRNA when administered alone, a combination of SST and IFN markedly induced iNOS mRNA in the cells. SST also modestly increased NO synthesis caused by interleukin-1 or bacterial lipopolysaccharide as a single agent, or in combination with IFN. On the other hand, SST had no effects on the NO synthesis produced by iNOS which were already induced. Thus, we found that SST stimulates cultured hepatocytes to produce NO by inducing iNOS gene expression under appropriate conditions. The capability of SST to induce NO biosynthesis might be related to the therapeutic efficacy of SST on the liver diseases.

Amino Acid Oxidoreductases

Effects of calcium channel antagonists on the induction of nitric oxide synthase in cultured cells by immunostimulants.

We investigated whether calcium channel antagonists would alter the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) alone or in combination with interferon-gamma (IFN gamma) in cultured J774 macrophages, rat vascular smooth muscle cells, rat renal mesangial cells, and rat cardiac myocytes. The induction of NO synthesis was determined by measuring nitrite, the stable end-product. The dihydropyridine calcium channel antagonists, nifedipine, manidipine, nitrendipine, benidipine, barnidipine, perdipine, and nilvadipine all reduced the LPS-induced nitrite production in a dose-dependent manner, each with a differing half-maximal inhibitory concentration, in cultured J774 macrophages. Nifedipine also inhibited nitrite production in vascular smooth muscle cells, mesangial cells, and cardiac myocytes. The half-maximal inhibitory concentrations of nifedipine were ranked as follows: smooth muscle cells < mesangial cells < cardiac myocytes. Diltiazem, at nontoxic concentrations, had no effect on the nitrite formation in the three cell types. Verapamil markedly increased the formation of nitrite in cardiac myocytes in response to LPS and IFN gamma, but not in vascular smooth muscle or mesangial cells. Exposure of cardiac myocytes to LPS and IFN gamma caused the expression of NO synthase mRNA that was significantly increased by verapamil. Thus, certain calcium channel antagonists modulate NO synthesis by altering the induction of NO synthase.

Adjuvants, Immunologic

Expression and characterization of the zeta 1 subunit of the N-methyl-D-aspartate (NMDA) receptor channel in a baculovirus system.

Using a baculovirus expression vector system, the zeta 1 subunit of the mouse N-methyl-D-aspartate (NMDA) receptor channel was expressed in Spodoptera frugiperda insect cells. The peptide corresponding to the C-terminus of the zeta 1 subunit was synthesized by using the multiple antigen peptide (MAP) system, and an antibody to the synthetic peptide was produced. Immunoblotting using the newly developed antibody revealed the major 122-kDa and the minor 104-kDa protein bands. The effect of tunicamycin on the immunoblots and [35S]methionine/[35S]cysteine metabolic radiolabeling suggested that the two bands corresponded to glycosylated and non-N-glycosylated forms, respectively. Membranes prepared from insect cells infected with the recombinant virus had the binding activity of antagonist ligand 5,7-[3-3H]dichlorokynurenate (DCKA) of a glycine recognition domain of the receptor. Both immunofluorescence labeling and the [3H]DCKA binding assays also showed a greater level of expression (Bmax = 51 pmol/mg protein) in the insect cells. The ligand binding characteristics of the receptors expressed in insect cells suggested that the single zeta 1 subunit protein has glycine antagonist binding properties comparable to those of the native NMDA receptor channels. The lack of DCKA-binding activity of the non-N-glycosylated NMDA receptor expressed in the presence of tunicamycin suggested that N-linked oligosaccharide is essentially required for expression of a functional receptor in insect cells. This is the first report describing the importance of N-glycosylation for the acquisition of ligand binding to NMDA receptor channel subunit protein.

Animals

Splicing mutations in the COL4A5 gene in Alport's syndrome: different mRNA expression between leukocytes and fibroblasts.

The COL4A5 gene from 40 patients with Alport's syndrome was examined using single-strand conformation substitution at the acceptor site (-2) of intron 50 and a G-to-C substitution at the donor site (+1) of intron 47, respectively. The transcript in peripheral leukocytes from the former had a 10-nucleotide deletion. This shortened transcript was derived from abnormal splicing in a cryptic acceptor site within exon 51. This could be translated into a protein with an alteration of three amino acids followed by premature termination, which eliminated 23 amino acids from the carboxyl end. Gene tracking revealed that the mother and a brother carried the mutant allele. In the latter, the transcript in leukocytes was normal, but that in cultured skin fibroblasts showed skipping of exon 47, the result being that 71 amino acids were absent. Glomerular basement membrane from the patient did not react with the anti-alpha 5(IV) antibody. His maternal grandmother, mother, and a sister, all with abnormal urinalysis, carried the mutant allele. Thus, the appearance of exons of the COL4A5 gene in leukocytes may differ from that in fibroblasts. If kidney mRNA is not available, mRNAs from cultured skin fibroblasts, in addition to leukocytes, can be used for gene analysis in subjects with Alport's syndrome.

Adolescent

N-linked glycosylation of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)-selective glutamate receptor channel alpha 2 subunit is essential for the acquisition of ligand-binding activity.

The N-linked glycosylation of the alpha 2 subunit of the mouse alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)-selective glutamate receptor (GluR) channel was characterized. The receptor subunit protein has five putative N-glycosylation sites. The recombinant receptor proteins were identified by [35S]methionine/[35S]cysteine metabolic labeling, western blot analysis, immunocytochemical detection, and [3H]AMPA binding experiments when expressed in insect Spodoptera frugiperda cells using a baculovirus system. The effect of tunicamycin on the metabolic labeling and immunoblots suggested that the two products, a major protein species of approximately 102 kDa and a minor species of approximately 98 kDa, correspond to glycosylated and unglycosylated forms, respectively, which was also supported by the enzymic deglycosylation experiments. Immunofluorescence staining of tunicamycin-treated cells expressing only the unglycosylated form differed little from that of tunicamycin-nontreated cells expressing both glycosylated and unglycosylated forms. The lack of AMPA-binding activity of the unglycosylated form expressed in the presence of tunicamycin suggested that N-glycosylation is required, directly or indirectly, for functional expression in insect cells for ligand binding. These results demonstrate that occupancy of at least one N-glycosylation site is required for the formation and maintenance of the GluR alpha 2 subunit protein in an active conformation for ligand binding. Possible roles of N-glycosylation of GluR alpha 2 subunit protein are discussed.

Animals

The effect of pentoxifylline on acid-induced alveolar epithelial injury.

BACKGROUND: Acid instillation into one lung is known to cause an increase in the permeability of the endothelium to protein in both the instilled and the contralateral lungs. Activated neutrophils are believed to be involved in causing this increased permeability. Pentoxifylline, a drug used in clinical practice, has multiple effects on neutrophils, including inhibition of phagocytosis, degranulation, and superoxide generation. This study investigated whether pretreatment with pentoxifylline would protect the alveolar epithelium or lung endothelium from injury. METHODS: The effect of acid instillation into one lung of anesthetized rabbits using several quantitative parameters was investigated. The quantification of the bidirectional movement of the alveolar (125I-albumin) and the circulating protein tracers (131I-albumin) was used as a measurement of the permeabilities of the lung epithelium and the lung endothelium in the acid-instilled lung. Bronchoalveolar lavage and measurement of the entry of the circulating protein tracer were used to assess the permeabilities of these barriers in the noninstilled lung. RESULTS: The instillation of HCl (pH 1.25, 1.2 ml/kg) into the right lung resulted in an increase in the protein permeability of the right lung's alveolar epithelium and endothelium as well as an increase in the permeability to protein of the left lung's endothelium. Pentoxifylline pretreatment attenuated the increase in the endothelial permeability of both lungs by 50% and restored the PaO2/FIO2 to normal in the pretreated animals exposed to acid injury. CONCLUSIONS: Acid aspiration causes a dramatic increase in the alveolar epithelial permeability of the acid-instilled lung, but the permeability of the alveolar epithelium of the contralateral lung remains normal. In contrast, unilateral acid instillation causes an increase in the permeability of the endothelium of both lungs. The increase in endothelial permeability can be attenuated by pretreatment with pentoxifylline administration, and this leads to restoration of normal gas exchange.

Animals

A low protein diet increases 4-nitrophenol-UDPglucuronosyltransferase but decreases chloramphenicol-UDPglucuronosyltransferase activity and mRNA level in livers of rats treated with polychorinated biphenyls.

We have examined the effects of dietary level of protein (5% or 30% in casein) on enzyme activities and mRNA levels of two xenobiotic-inducible UDPglucuronosyltransferase (UDPGT) enzymes, such as chloramphenicol-UDPGT (CP-UDPGT) and 4-nitrophenol-UDPGT (4NP-UDPGT), in the livers of rats treated or not treated with polychlorinated biphenyls (PCB). In animals fed 5% casein and not treated with PCB, CP-UDPGT activity tended to be lower than in rats fed 30% casein. In contrast, 4NP-UDPGT activity was higher in rats fed 5% casein. In rats treated with PCB, the activities of both enzymes were increased. CP-UDPGT mRNA level was higher (1.4-fold) in rats fed 30% dietary casein than in those fed 5% casein. In contrast, 4NP-UDPGT mRNA level was higher (2.8-fold) in rats fed 5% casein than in those fed 30% casein. These changes in mRNA levels paralleled those in the activities of the two enzymes. The data indicate that the dietary protein is an important factor controlling the expression of hepatic xenobiotic-inducible UDPGT genes and modulates the capacity of the liver to metabolize foreign compounds.

Animals

Pentamethyl-hydroxychromane, vitamin E derivative, inhibits induction of nitric oxide synthase by bacterial lipopolysaccharide.

Vitamin E, a lipophilic antioxidant, has effectively inhibited the activation of cytokine-induced nuclear factor kB (NFkB). Since NFkB plays a critical role in the induction of an isoform of nitric oxide synthase (iNOS) gene by lipopolysaccharide (LPS), we investigated the effect of a vitamin E derivative, pentamethyl-hydroxychromane (PMC), which is an extremely potent inhibitor of NFkB activation, on the induction of nitric oxide (NO) synthesis and iNOS mRNA by LPS. PMC inhibited the LPS-stimulated induction of NO production in a concentration-dependent fashion in cultured J774 macrophages and rat vascular smooth muscle cells without evidence of cytotoxicity. However, the addition of PMC to J774 macrophages after the induction of iNOS did not inhibit NO production. Treatment of J774 macrophages with LPS resulted in a significant expression of iNOS mRNA, which was profoundly reduced by PMC. Data suggest that PMC inhibits the induction of iNOS by preventing iNOS gene expression through inhibition of NFkB activation.

Amino Acid Oxidoreductases

Vesnarinone inhibits induction of nitric oxide synthase in J774 macrophages and rat cardiac myocytes in culture.

OBJECTIVE: We investigated whether vesnarinone alters the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) or in combination with interferon-gamma in cultured J774 macrophages and rat cardiac myocytes. METHODS: The induction of NO synthesis was determined by measuring the stable end-product nitrite. The cytotoxic effect of vesnarinone was assessed by measuring cell respiration. Any change in mRNA levels for NO synthase (NOS) was determined by RT-PCR. RESULTS: Stimulation by LPS or in combination with interferon-gamma increased the accumulation of nitrite in the supernatant of J774 macrophages or cardiac myocytes. NOS induction accounted for this accumulation of nitrite, as dexamethasone, NG-methyl-L-arginine, and cycloheximide each reduced the production of nitrite in both types of cells. Vesnarinone produced a significant decline in the cumulative production of nitrite in both types of cells without evidence of cytotoxicity. However, the addition of vesnarinone after induction of NOS did not inhibit nitrite production. Treatment with LPS or in combination with interferon-gamma led to a significant expression of NOS mRNA in both types of cells that was significantly reduced by vesnarinone. CONCLUSIONS: Vesnarinone inhibited NO synthesis by inhibiting the induction of NOS in J774 macrophages and cardiac myocytes. This drug may exert a beneficial effect in patients with heart failure, in part, by attenuating the production of NO.

Animals

Distribution of lectin binding in the testes of the musk shrew, Suncus murinus.

Distribution of lectin binding in the testis of the musk shrew, Suncus murinus, was investigated by light and transmission electron microscopy. Not only spermatogenic cells but also Sertoli cells bound some lectins. Canavalia ensiformis agglutinin (Con A) and wheat germ agglutinin (WGA, Triticum vulgaris), indicating the presence of D-mannose and N-acetyl-D-glucosamine respectively, showed an intense reaction in the acrosomal region of early to late spermatids. Ricinus communis agglutinin I (RCA-I), peanut agglutinin (PNA, Arachis hypogaea), Bauhinia purpurea agglutinin (BPA), soybean agglutinin (SBA, Glycine max), revealing the presence of D-galactose and/or N-acetyl-D-galactosamine, bound to the acrosomal region from Golgi to acrosome-phase spermatids and abruptly decreased in intensity in maturation-phase spermatids. GS-II, indicating the presence of N-acetyl-D-glucosamine, gave an intense reaction only in the acrosome of acrosome-phase spermatids. These findings demonstrate that the appearance/disappearance of some glycoconjugates in the spermatid acrosome occurs in the musk shrew during acrosomal formation. Additionally, RCA-I, PNA and BPA revealed a strong reaction in the cytoplasm of Sertoli cells. The reaction that was observed in the intramembranous region of Sertoli cell cytoplasm at the electron microscope level appeared from stages VIII to XIII but not from stages I to VII. This finding suggests that glycoconjugates containing D-galactose may change stage-dependently in the musk shrew Sertoli cell.

Acrosome

[The relation between delivery method and prognosis for very low birth weight infants].

To further understand the relationship between perinatal factors and prognosis (neonatal and infantile death and major handicaps), we retrospectively studied 128 singletons weighing less than 1,500g (very low birth weight; VLBW) infants, without maternal complications, IUGR or major congenital anomalies. The gestational age (mean +/- SD) at delivery and the birth weight (mean +/- SD) of subjects were 27.1 +/- 2.0 weeks and 1,041.1 +/- 264.1g, respectively. The results of the current study were as follows: 1) Malpresentation, low Apgar score (APS) and Respiratory distress syndrome (RDS) were observed more frequently in non-intact survivors than in intact survivors with statistical significance. Although the occurrence of fetal distress was correlated with low pH in the umbilical artery, no significant correlation was evident between the prognosis and either of the two above mentioned factors. The intact survivors had a significantly high frequency of PROM despite no correlation with signs of infection (WBC, CRP). 2) As to delivery methods in terms of prognosis, a cephalic-vaginal group had the best prognosis and a breech-vaginal group had the worst, with statistical significance. A higher frequency of poor prognosis for infants was found in a malpresentation group with cesarean delivery and cervical dilation of more than 4cm. Thus, vaginal delivery is a possible option in case of cephalic VLBW infants.

Delivery, Obstetric