Cortical vasodilatation produced by vasoactive intestinal polypeptide (VIP) and by physiological stimuli in the cat

In chloralose-urethanized cats, vasoactive intestinal peptide (VIP), applied by superfusion in steady-state concentration (10(-10)-10(-6) M) onto cortical vessels in situ resulted in a rapid concentration-dependent vasodilatation in vessels that were mildly constricted by prostaglandin F2 alpha (PGF2 alpha) (5 X 10(-5) M) or hypocarbia (PaCO2 = 26). The maximum dilatation produced by VIP (10(-6) M) was about 60% over baseline in pial arteries and 40% in pial veins. Blockade of local neuronal activity with tetrodotoxin (TTX) (10(-5) M) had no effect on the VIP-evoked dilation of pial vessels. Activation of the cortex by either direct electrical stimulation or indirectly by stimulation of the mesencephalic reticular formation (MRF) resulted in a rapid dilatation of pial arterioles and venules. The vasodilatory effects of VIP and of cortical activation via direct cortical stimulation were not blocked by phentolamine (10(-4) M), propranolol (10(-4) M), atropine (10(-4) M), or naloxone (10(-4) M), indicating that the stimulated vasodilatation was not mediated by adrenergic, cholinergic, or opiate receptors. The dilatory effects of MRF, but not direct cortical stimulation, were not blocked by TTX. VIP antiserum (1:25) preincubated in cortical cups had no effect on resting vessel diameter, but resulted in a significant, though subtotal, reduction in the vasodilatation elicited by direct cortical and MRF stimulation. Normal rabbit sera or VIP antiserum preincubated with saturating amounts of VIP were ineffective. In similar experiments, pial arteriolar and venular dilation evoked by hypercarbia was not attenuated by cortically applied VIP antisera. These observations suggest that pial dilation evoked by local increases in neuronal activity may be mediated in part by the local release of VIP from intrinsic neurons. Such a substrate would define a close obligatory coupling between local neuronal activation and local perfusion, such that nutritive flow could be enhanced prior to the onset of any metabolic deficit.

Structure and origins of the HZ2-feline sarcoma virus

The HZ2-feline sarcoma virus (HZ2-FeSV) is a replication-defective acute transforming feline retrovirus with oncogene homology to Abelson murine leukemia virus (A-MuLV) (P. Besmer, W.D. Hardy,Jr., E. E. Zuckerman, P. J. Bergold, L. Lederman, and H. W. Snyder, Jr. (1983) Nature (London) 303, 825-828). In contrast to A-MuLV which was isolated from a hematopoietic tumor, the HZ2-FeSV derives from a multicentric fibrosarcoma. We have molecularly cloned the HZ2-FeSV provirus from mink HZ2-FeSV nonproducer cells. The molecularly cloned HZ2-FeSV provirus is biologically active upon transfection of NIH 3T3 indicator cells. The genetic structure of the HZ2-FeSV provirus was determined by EM heteroduplex and Southern blot analysis. The HZ2-FeSV has a 6.8 kb-viral genome with the structure: 5' delta gag-abl-delta pol-delta env 3'. The abl insert, which is 1.4 kb, is located 1.9 kb from the 5' end and 3.5 kb from the 3' end of the viral genome. The 5' 1.9 kb in the HZ2-FeSV are colinear with 5' FeLV sequences, and the 3' 3.5 kb are colinear with 3' FeLV sequences, with the exception of a 0.85-kb deletion in the env gene. HZ2-FeSV v-abl and A-MuLV v-abl share 1.2 kb of abl sequences which are known to specify the protein kinase domain of the abl gene product and are necessary for fibroblast transformation in vitro. The DNA from several tumor tissues of cat 3590 from which the HZ2-FeSV was obtained was found to contain several HZ2-FeSV-related proviruses including the HZ2-FeSV. The variant HZ2-FeSVs have indistinguishable 5' gag-abl sequences; however, they differ in 3' sequences which likely do not include any abl sequences. The DNAs from fibrosarcomas obtained by inoculation of kittens with tumor extract were found to contain variant HZ2-FeSV proviruses as well. Taken together these results indicate a role for the HZ2-FeSVs in sarcomagenesis.

Isolation of temperature-sensitive tyrosine kinase mutants of v-abl oncogene by screening with antibodies for phosphotyrosine

Temperature-sensitive protein-tyrosine kinase (EC 2.7.1.112) mutants of the oncogene v-abl have been obtained by a direct screening of kinase mutants in bacteria. The v-abl oncogene was expressed in Escherichia coli as a trpE/v-abl fusion protein from the trp promoter. The expression plasmid was mutagenized in vitro and then transfected into E. coli. Bacteria that produced defective tyrosine kinases were distinguished from those producing wild-type v-abl kinases by hybridization with antibodies specific for phosphotyrosine. Two independent mutations that generated temperature-sensitive tyrosine kinases were found to be located in a 12-amino acid region in the tyrosine kinase domain of the v-abl-encoded protein. These mutant v-abl oncogenes displayed temperature-sensitive transforming activity when expressed in NIH 3T3 cells. Cells transformed by these temperature-sensitive tyrosine kinase mutants could be shifted between the transformed and untransformed states by changing their growth temperature. These results confirmed the crucial role of tyrosine kinase activity in the v-abl-mediated oncogenesis.

Detection of phosphotyrosine-containing proteins in polyomavirus middle tumor antigen-transformed cells after treatment with a phosphotyrosine phosphatase inhibitor

Cells transformed with the middle tumor antigen (mT) of polyomavirus were treated with sodium orthovanadate (Na3VO4), an inhibitor of phosphotyrosine phosphatases, to enhance for the detection of cellular proteins which are phosphorylated on tyrosine. Na3VO4 treatment of mT-transformed rat F1-11 cells resulted in a 16-fold elevation in the level of phosphotyrosine associated with total cellular proteins. Parental F1-11 cells displayed only a twofold increase in phosphotyrosine following Na3VO4 treatment. The abundance of phosphotyrosine in Na3VO4-treated mT-transformed F1-11 cells was twofold higher than in untreated Rous sarcoma virus (RSV)-transformed F1-11 cells and 3.5-fold lower than in Na3VO4-treated RSV-transformed F1-11 cells. Tyrosine phosphorylation of many cellular proteins, including p36, the major substrate of the RSV pp60v-src protein, was detected in Na3VO4-treated mT-transformed F1-11 cells at levels comparable to those observed in RSV-transformed cells. Some of the major protein species recognized by antiphosphotyrosine antibodies in Na3VO4-treated mT-transformed cells displayed electrophoretic mobilities similar to those detected in RSV-transformed F1-11 cells. Tyrosine phosphorylation of p36 was also detected in fibroblasts infected with polyomavirus. There was no detectable difference in the kinase activity of pp60c-src:mT extracted from untreated and Na3VO4-treated mT-transformed cells; however, Na3VO4 treatment of F1-11 and mT-transformed F1-11 cells was shown to inhibit the activity of phosphotyrosine phosphatases in a crude assay of total cellular activity with pp60v-src as the substrate. Thus, Na3VO4 treatment may allow the detection of phosphotyrosine-containing proteins in mT-transformed cells by preventing the turnover of phosphate on substrates phosphorylated by activated cellular protein-tyrosine kinases associated with mT. These results suggest that tyrosine phosphorylation of cellular proteins may be involved in the events that are responsible for mT-induced cellular transformation.

Correlation between hepatic hepatitis B core antigen and serum hepatitis B virus-DNA levels in patients with chronic hepatitis B virus infections in Taiwan

Paired liver biopsy specimens and serum samples from 76 patients with chronic hepatitis B virus (HBV) infection were taken for staining of hepatitis B core antigen (HBcAg) by immunoperoxidase and testing of HBV-DNA by a spot hybridization technique, respectively. Thirty-two tissue specimens showed positive staining for HBcAg in their hepatocytes. The two patients with diffuse HBcAg expression in liver tissue also had high serum concentrations of HBV-DNA (greater than 10 pg/10 microL). Among 30 patients with focal HBcAg distribution, 28 patients (93.3%) had measurable levels of serum HBV-DNA and 17 patients (60.7%) had high levels of serum HBV-DNA. Of 44 patients without hepatic HBcAg expression, only 12 patients (27.3%) had detectable serum HBV-DNA, and most patients (93.1% [11/12]) had low concentrations (less than 10 pg/10 microL). Nineteen patients had superimposed hepatitis D virus infection, and, of these, three patients (15.8%) had detectable serum HBV-DNA in low concentrations, while one of the three patients had stainable HBcAg in his hepatocytes with focal distribution. Two of the three patients with hepatitis A virus superinfection who had focal HBcAg expression in their liver tissue had serum HBV-DNA levels that were high during the acute phase of hepatitis A virus infection, and in one patient his serum HBV-DNA levels further increased from 10 pg/10 microL to 40 pg/10 microL during the recovery phase. Thus, measurement of serum HBV-DNA levels in patients with chronic HBV infection correlated well with their hepatic HBcAg expression, and both represent the precise status of HBV replication.

Hepatitis D virus (delta agent) superinfection in an endemic area of hepatitis B infection: immunopathologic and serologic findings

In 86 Chinese patients with histologically proven hepatitis B surface antigen (HBsAg) positive chronic hepatitis and serum alanine aminotransferase levels exceeding 200 U/l, antibody to hepatitis D antigen (HDAg) was detected more frequently in sera from hepatitis B e antigen (HBeAg) negative patients (11/35, 31.4%) than in HBeAg positive (4/51, 7.8%) patients (p less than 0.02). 10 liver biopsy specimens (76.9%) from 13 chronic hepatitis B patients with superimposed hepatitis D virus (HDV) infection, showed positive staining for HDAg in their hepatocytes. Neither HBsAg nor hepatitis B core antigen (HBcAg) was found in the liver in 12/13 patients with superimposed HDV infection. However, in liver biopsy specimens from 42 patients without HDV superinfection, HBsAg was stained positively in 41 patients (97.6%), and HBcAg in 24 patients (47.1%). Using dot blot hybridization technique, serum hepatitis B virus (HBV) DNA was detected in 62.1% (41/66) of patients without HDV superinfection, while it was detected only in 10.0% (1/10) of patients who had HDV superinfection. It is concluded that HDV superinfection plays a significant role in Taiwan in HBeAg negative chronic hepatitis B patients with clinical "exacerbation". The data show clear evidence of HDV interfering with the replication of HBV.

Retrograde axonal transport of true blue dye by the peripheral autonomic nerves in canine nasal mucosa

In this study we employed retrograde axonal transport of (E)-2,2'-vinylendi-benzofuran-5-carboxamidin-diaceturate+ ++ or true blue (TB) to study the peripheral autonomic innervation of the canine nasal mucosa. After injection of TB into the nasal mucosa, labeled neurons were found in the ipsilateral sphenopalatine ganglion (SPG) and the superior cervical ganglion (SCG). There were no labeled neurons in the middle cervical or stellate ganglia. This indicated that the origin of the postganglionic sympathetic fibers of the nasal mucosa was only from the ipsilateral SCG. When TB was injected into the nasal mucosa of dogs following a caudal or ethmoidal neurectomy, labeled neurons could still be found in the SPG and SCG. When TB was injected into the nasal mucosa of dogs following ethmoidal and vidian neurectomies or with maxillary neurectomy added, some labeled neurons could still be found in both the ipsilateral SPG and SCG. These results support the concept that another pathway--perhaps perivascular--exists for postganglionic sympathetic fibers other than the vidian and ethmoidal nerves. Labeled neurons were still observed in SPG when TB was applied to the canine nasal mucosa following neurectomy of either the ethmoidal or the caudal nasal nerve. However, retrograde labeled neurons could not be found in SPG following simultaneous neurectomies of the ethmoidal and caudal nasal nerves. These results show that the postganglionic parasympathetic fibers originating in the SPG travel along the ethmoidal and caudal nasal nerves.

Protein tyrosine phosphorylation in the cell cycle of BALB/c 3T3 fibroblasts

Cell cycle-dependent regulation of protein tyrosine phosphorylation in normal BALB/c 3T3 fibroblasts was examined by immunoblotting with a high-affinity antibody specific for phosphotyrosine. At least 15 different tyrosine-phosphorylated proteins are found in normal 3T3 cells. The level of tyrosine phosphorylation is higher in growing cells than in quiescent cells. However, a prominent tyrosine-phosphorylated protein of Mr 150,000 is present in quiescent cells, and its level is inversely proportional to the growth rate of these fibroblasts. Stimulation of quiescent cells with serum causes a major, yet transient, increase in tyrosine phosphorylation. The immediate tyrosine phosphorylation reactions in response to serum stimulation are independent of protein synthesis, but tyrosine phosphorylation reactions occurring later in the G1 phase of the cell cycle are inhibited by cycloheximide. Thus, tyrosine phosphorylation of proteins in normal 3T3 cells occurs predominantly at the G0 to G1 transition of the cell cycle. Maintenance of steady-state tyrosine phosphorylation is dependent on the presence of serum, but at least one tyrosine phosphorylation reaction occurs in the absence of cell growth.

Hepatitis B and D virus infection among drug abusers in Taiwan

Approximately 15 to 20% of the general population in Taiwan are chronic hepatitis B surface antigen (HBsAg) carriers. However, the incidence of hepatitis D virus (HDV) infection is low (5-8%) in patients with HBsAg-positive chronic liver diseases in this area. To evaluate the prevalence of hepatitis B virus (HBV) and HDV infection among drug abusers in Taiwan, serum samples were collected from 152 drug abusers at the Taipei Municipal Anti-Narcotic Institute and test for HBV and HDV markers. Of these, 24 (15.8%) were HBsAg positive, and only 15 (9.9%) were seronegative for all HBV markers. Of the 115 intravenous drug abusers, serum antibody to hepatitis D antigen (anti-HD) was positive in 78.9% of 19 persons who were HBsAg positive, and in 7.5% of 80 persons who were positive for antibody to HBsAg (anti-HBs). Anti-HD was not detected in the sera from all 37 nonintravenous drug abusers regardless of the status of their HBV markers. Also, none of 63 asymptomatic HBsAg carrier pregnant women or 23 patients with acute type B viral hepatitis had measurable anti-HD in their sera. Thus, the high frequency of HDV detected among Chinese HBsAg carrier intravenous drug abusers in Taiwan is similar to that reported in Western countries.

Effects of H2-receptor antagonists on the rat liver after partial hepatectomy or carbon tetrachloride-induced hepatic injury

A total of 512 male rats were used to investigate the effects of H2-receptor antagonists on the liver after two-thirds hepatectomy or after carbon tetrachloride (CCl4)-induced hepatic injury. The serum aminotransferase levels in hepatectomy rats were significantly elevated as compared with those of rats with the sham operation 1 and 2 days after the operation. However, there were no differences in the serum aminotransferase levels and liver regeneration rates among the groups of hepatectomy rats who were treated with saline, cimetidine, or ranitidine. The injections of cimetidine or ranitidine did not induce a significant increase in serum amino-transferase levels or increase the severity of liver cell necrosis in CCl4-treated rats, as compared with the CCl4-treated rats who received saline injection. Thus, our data indicate that H2-receptor antagonists do not inhibit liver regeneration in rats after two-thirds hepatectomy or exert a detrimental effect on the liver cell necrosis in rats after CCl4-induced hepatic injury.

Effects of eight-week treatment with histamine H2-antagonists or an antacid on plasma levels of histamine and serotonin in duodenal ulcer patients

The effects of 8-week treatment with oral histamine H2-antagonists (ranitidine or cimetidine) or an antacid on plasma levels of histamine and serotonin were studied in duodenal ulcer patients. Histamine H2-antagonists significantly elevated plasma histamine levels, however, they markedly decreased serotonin concentrations by the 4th week of treatment. Antacid treatment similarly increased histamine levels without significantly affecting blood serotonin. It is concluded that changes in intragastric or intraduodenal acidity affect histamine release, as reflected by increased blood levels; serotonin secretion could be influenced by blocking histamine H2-receptors, possibly those located mainly in the gastrointestinal tract.

Surface structure recognized for covalent modification of the aspartate receptor in chemotaxis

The aspartate receptor involved in chemotaxis is modified by methyl esterification at four distinct glutamate residues during the adaptive response of this receptor. To explain the high degree of specificity of this modification, it has been proposed that the methyltransferase recognizes the sequence Glu-Glu-Xaa-Xaa-Ala-Ser/Thr in an alpha-helical conformation and methylates the second glutamate in this sequence. This hypothesis is strengthened here by localized mutagenesis studies. By reversing the alanine-threonine sequence to threonine-alanine at the principal site of methylation, Glu-309, a factor of 4 decrease in reactivity was achieved. Thus, the rate of methylation of this site is sensitive to the reversal of two residues of similar structure. These residues are somewhat distant in sequence from the glutamate that is modified but are adjacent in space if an alpha-helical structure is present. The other sites of modification, Glu-295, Glu-302, and Glu-491, are slightly increased in reactivity in the mutant. The 4-fold change in reactivity of the major site of methylation obtained with a relatively subtle change supports the recognition sequence hypothesis, including its structural implications. It is noted, in addition, that chemotaxis of bacteria expressing the mutant receptor does not seem to be greatly altered. This might be explained by the observation that the overall methylation levels of the mutant and wild-type receptors are similar.

Kinetics of receptor modification. The multiply methylated aspartate receptors involved in bacterial chemotaxis

A method for determining the extent of methyl esterification of each of the four potential sites on the aspartate receptors involved in chemotaxis in Escherichia coli and Salmonella typhimurium is presented. In this procedure, radioactive methyl esters are incorporated into the receptors, the receptors are cleaved by trypsin and the V8 protease from Staphylococcus aureus, and the four fragments containing sites of methylation are separated by high performance liquid chromatography. Using this technique, we find that the rate of methyl esterification increases at all four sites after stimulation with the "attractant" aspartate, suggesting that all four sites of modification are involved in adaptation to aspartate. We also find that the rate of methyl esterification at each site is correlated with the homology between the protein sequence at that site and the "consensus" sequence, Glu-Glu-X-X-Ala-Thr/Ser.

The influence of partial hepatectomy and carbon tetrachloride on rat stomachs

Carbon tetrachloride (CCl4) injection, but not partial hepatectomy, significantly increased gastric acid secretion and ulceration in rats. Both procedures did not influence serum IgG levels, but markedly elevated serum alanine and aspartate aminotransferase activities. It appears that short-term liver injury produced by CCl4, but not hepatectomy, adversely affects rat stomachs.

Prevention of maternal-infant hepatitis B virus transmission by immunization: the role of serum hepatitis B virus DNA

Sera from 108 HBsAg carrier mothers at delivery and their respective offspring at birth and at 6 months of age were examined for hepatitis B virus DNA by the dot-blot hybridization technique. Hepatitis B virus DNA was detected in 83% of 88 carrier mothers who were HBeAg positive, and in 10% of 20 carrier mothers who were HBeAg negative. All five infants born to HBeAg-positive carrier mothers with hepatitis B virus DNA levels over 80 pg per 10 microliters of serum were infected by hepatitis B virus, in spite of receiving hepatitis B immunization. All 17 infants without hepatitis B immunization who were born to HBeAg and hepatitis B virus DNA-positive carrier mothers developed hepatitis B virus infection. Of 56 infants born to HBeAg and hepatitis B virus DNA-positive carrier mothers and who had received hepatitis B immunization, a higher hepatitis B virus infection rate was found in a group of infants whose sera hepatitis B virus DNA were positive (15/16, 93.8%) than in infants whose sera were negative (17/40, 42.5%) at birth (p less than 0.0005). These data suggest that the assay for hepatitis B virus DNA in sera of HBsAg carrier mothers at delivery or their infants at birth will predict the efficacy of hepatitis B immunization for prevention of maternal-infant hepatitis B virus transmission.

Controlled trial of vasopressin plus nitroglycerin vs. vasopressin alone in the treatment of bleeding esophageal varices

Thirty-nine patients admitted during a 16-month period for acute bleeding from varices confirmed by emergency endoscopy were randomized to receive either continuous intravenous infusions of vasopressin alone (0.66 units per min) (Group I: 19 patients) or vasopressin plus sublingual nitroglycerin (0.6 mg every 30 min for 6 hr) (Group II: 20 patients). The two groups of patients were similar in the type and severity of their cirrhosis. Bleeding was controlled initially in 47% (9/19) of the patients in Group I and 55% (11/20) of the patients in Group II after 6 hr of infusion (not statistically significant). Complete control of bleeding during 24 hr of infusion was achieved in only 4 of 19 patients in Group I (21%) but in 9 of 20 in Group II (45%). This difference is not statistically significant. The total number of patients with complications during infusions were significantly different statistically in the vasopressin and vasopressin-nitroglycerin groups, respectively (17/19 vs. 7/20, p less than 0.001). Major complications requiring immediate cessation of infusions were observed in 6 of 19 of the patients in Group I (32%) and in 2 of 20 in Group II (10%) (p less than 0.05). Mortality (58% in Group I, 55% in Group II) and transfusion requirements were similar in the two groups. This study shows that the addition of sublingual nitroglycerin to intravenous vasopressin does not alter the efficacy of vasopressin alone in controlling hemorrhage from esophageal varices, but it does significantly reduce the complications.

Glomerulonephritis in ankylosing spondylitis

There have been a few reports suggesting the association between glomerulonephritis (GN) and ankylosing spondylitis (AS). The reported glomerulonephritides include IgA nephropathy, mesangial proliferative GN and membranous nephropathy. From January 1983, through December 1984, we observed 5 cases of GN among 116 cases of definite AS. Three of them were IgA nephropathy. The other two were mesangial proliferative GN, with IgM deposit in one case and isolated C3 deposit in another. Microscopic hematuria was observed in all of them. The renal function and 24-hour urine protein excretion were all within normal limits. Serum IgA level increased in all but the case of mesangial proliferative GN with IgM deposit. All except one had the antigen of HLA-B27. Serum IgA level was determined in 78 cases (86 estimations) of AS. The mean value was 399.6 +/- 15.0 mg/dl (mean +/- SE) (normal range: 100-350 mg/dl). Fifty-four of them (63%) had a value higher than 350 mg/dl. The interrelationship of AS and IgA nephropathy was discussed.

Neurotransmitter modulation of VIP release from cat cerebral cortex

The cortical release of vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) in vivo was examined by superfusion of the pial surface of the cerebral cortex of the cat. The modulation of cortical VIP release by several neurotransmitters [gamma-aminobutyric acid (GABA), opioids, norepinephrine, acetylcholine, and glutamate] normally present in the cerebral cortex was studied by administering respective agonists and antagonists for their receptors. Although GABA and opiate agonists did not influence the resting release of VIP-LI, GABA antagonists (picrotoxin and bicuculline) and opiate antagonists (naloxone and naltrexone) significantly elevated the resting release. The evoked release from cortex of VIP-LI (by electrical stimulation of the cortex or mesencephalic reticular formation) was suppressed by GABA and mu- but not delta-, kappa-, or sigma-opioid receptor agonists. Glutamate and kainic acid increased the resting release of VIP-LI from the cerebral cortex. Noradrenergic (alpha 2 but not alpha 1) displayed an inhibitory effect on the evoked release of cortical VIP-LI release. Resting VIP-LI release was enhanced by cholinergic agents (carbachol). The facilitatory effects of mesencephalic reticular formation stimulation on VIP-LI release were demonstrated by atropine. These observations suggest characteristic interactions reflecting the circuitry modulating the activity of cortical VIP-releasing neurons.

Isolation of antibodies for phosphotyrosine by immunization with a v-abl oncogene-encoded protein

Immunization of rabbits with a tyrosine-phosphorylated v-abl protein resulted in the production of antibodies for the v-abl protein and for phosphotyrosine. The antiphosphotyrosine antibodies could be purified by affinity chromatography with O-phosphotyramine coupled to Sepharose. These antibodies detected a variety of tyrosine-phosphorylated proteins, including receptors for peptide growth factors. The usefulness of these antibodies was demonstrated by the detection of previously unidentified tyrosine-phosphorylated proteins in v-src-, v-abl-, and v-erbB-transformed cell lines.

Immunoprophylaxis of infection with hepatitis B virus in infants born to hepatitis B surface antigen-positive carrier mothers

Infants born to carrier mothers positive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) received 5 micrograms of hepatitis B virus (HBV) vaccine on four occasions. Group 1 received vaccine only, group 2 received vaccine plus hepatitis B immune globulin (HBIG) at birth, and group 3 received vaccine plus HBIG at birth and at one month. Infants born to HBeAg-positive mothers (group 4) received a reduced dose of vaccine (2.5 micrograms) on three occasions as well as HBIG at birth. As compared with 78.4% of the control group (infants whose parents refused vaccination) who became chronic HBV carriers at the age of 14 months, the protective efficacy rate of vaccination was 75.3% in group 1,85.5% in group 2,89.7% in group 3, and 87.2% in group 4. HBV vaccine (5 micrograms) was also given to infants born to HBsAg-positive, HBeAg-negative mothers on four on four occasions. The antibody response to HBsAg in vaccine recipients was 12% after the first dose, 44% after the second dose, and 75% and 100% at six months and 1.5 years of age, respectively.

Combined passive and active immunization for interruption of perinatal transmission of hepatitis B virus in Taiwan

We attempted a clinical trial to interrupt transmission of hepatitis B virus (HBV) infection from hepatitis B surface antigen (HBsAg) positive and hepatitis Be antigen (HBsAg) positive mothers to their infants in Taiwan. Screening of 5,595 pregnant women revealed that 856 (15.3%) were HBsAg positive. Three hundred and sixty-one (42.2%) of the HBsAg positive pregnant women were HBeAg positive. Infants born to HBsAg and HBeAg positive mothers were randomized into 3 groups to receive the HBV vaccine alone or combined with hepatitis B immune globulin (HBIG). HGV vaccine was given at 2, 6, and 10 weeks after birth. Group I received HBV vaccine alone while Group II received HBV vaccine in combination with HBIG at birth and group III received HBV vaccine plus HBIG at birth and again at one month old. Group IV constituted the control group when their parents refused vaccination. At 6 months of age, the HBV carrier rate was 23.7% (9/38) in Group I, 11.1% (4/36) in Group II, and 5.3% (2/38) in Group III infants. Compared with 90% of infants who became HBV carriers in the control group (Group IV), the efficacy of HBV vaccination in preventing HBV infection among these high risk infants at the 6th month was 73.7% in Group I, 87.7% in Group II, and 94.1% in Group III. The antibody to HBsAg (anti-HBs) positivity rate in sera of Group I, II, III infants at 6 months of age was 79.0%, 88.9% and 94.7%, respectively. These initial results indicate that combined passive and active immunization is efficacious in interrupting perinatal transmission of HBV infection.

Studies on the in vivo release of vasoactive intestinal polypeptide (VIP) from the cerebral cortex: effects of cortical, brainstem and somatic stimuli

The release of vasoactive intestinal polypeptide (VIP) from the surface of the sensorimotor (parietal) cortex of anesthetized cats was measured by radioimmunoassay (RIA) procedures. Two types of anesthetics were examined (chloralose-urethane and halothane). Increasing the dose or concentration of anesthetics produced a suppression of electrocortical activity and resulted in a reduction in the resting release of VIP from cerebral cortex. The mean rate of resting release of endogenous VIP in cats anesthetized with chloralose-urethane was 16.8 +/- 4.6 fmol/30 min/cm2 cortex. Although there were differences in the basal levels of VIP-like immunoreactivity (VIP-LI) among different animals, the baseline levels of VIP-LI varied little during the initial period of 6-7 h period of anesthesia with chloralose-urethane (40 and 300 mg/kg). Examination of representative electrocorticography which corresponded with the superfusion period revealed an association between stable levels and a relatively invariant pattern of electrical activity. All experimental manipulations were carried out during the period of stable release. The rate of release was increased by focal, unilateral stimulation of the cerebral cortex both ipsilateral and contralateral to the side of stimulation (3.2 +/- 1.1 and 1.4 +/- 0.5 times the resting release, respectively). Bilateral stimulation of the mesencephalic reticular formation (MRF) produced a frequency-dependent increase in cortical VIP release over the range of 60-100 Hz. Bilateral electrical stimulation of sciatic nerves at intensities that recruit A delta and C fibers failed to consistently increase the release of VIP-LI from the cortex in chloralose-urethane anesthetized cats but did evoke a significant increase of cortical VIP output in cats anesthetized with 1.5 and 1% halothane. Removal of calcium ions from the superfusing fluid and substitution of cobalt (a calcium channel blocker) or EDTA (a calcium chelating agent) for calcium ions did not affect the resting release of endogenous VIP, but attenuated the increase in VIP release normally evoked by electrical stimulation of the cortical surface or MRF. Tetrodotoxin (TTX), which blocks sodium channels and thus blocks the propagation of nerve impulses, did not influence the resting release of VIP. TTX, at concentrations that prevent the increase in VIP release evoked by veratridine, greatly enhanced the surface-stimulated release but abolished the increase in VIP release evoked by MRF stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Localization of tyrosine kinase-coding region in v-abl oncogene by the expression of v-abl-encoded proteins in bacteria

A series of plasmids containing different segments of the v-abl oncogene have been constructed to express different portions of the v-abl protein in bacteria. The tyrosine kinase activity of these proteins was determined by an in vitro assay employing histones or angiotensin II as substrates for the v-abl-encoded tyrosine kinase. These experiments show that the 5'-1.2 kilobases of v-abl is necessary and sufficient to produce an active tyrosine kinase which is functional as a monomeric soluble protein. The kinase-coding region corresponds to the minimal region of v-abl required for the transformation of fibroblasts. The kinase-coding region also coincides with the conserved protein sequences which are found in other tyrosine kinases. A compact domain of the v-abl protein including this kinase-coding region can accumulate to high levels in bacteria. The C-terminal region of the v-abl protein is not needed for the kinase activity and is rapidly degraded in bacteria.

Studies on RNA ligase activity in the brain and liver cells of mouse

RNA ligase in eukaryotic mammalian cells was studied by using mouse brain and liver cell extracts as enzyme sources and Oligo A as substrates. RNA ligase activity was determined by measuring the formation of alkaline phosphate-resistant product from 5'-32P-terminated Oligoribonucleotides. Under appropriate conditions, the activity of this enzyme in brain and liver cells may vary between 16-49 mU/ml. The joining way between donor and acceptor is 5'-P----3'-OH. Further studies were carried out by using synthetic UpCpU and 32pNp as substrates and crude enzyme preparations from extracts of cell nuclei of brain and liver as enzyme sources. RNA ligase activity was examined by homochromatography and autoradiography. A clear joining product was demonstrated and then isolated from the reaction mixture by DEAE-Sephadex A25 column chromatography. The eluted fractions were identified by DEAE-cellulose thin layer chromatography. The joining product was hydrolyzed either with KOH or with alkaline phosphatase, the autoradiographic spot of the product disappeared. In this case the joining way between donor and acceptor is 3'-P----5'-OH instead of 5'P----3'-OH. All this indicated that in extracts of mouse brain and liver cells most probably exists some other kind of RNA ligase, which differs from the T4 RNA ligase in the joining way.

A v-sis oncogene protein produced in bacteria competes for platelet-derived growth factor binding to its receptor

The oncogene of simian sarcoma virus, v-sis, encodes a protein which is homologous to human platelet-derived growth factor (PDGF). This v-sis-encoded protein was expressed in bacteria using an inducible promotor of lambda phage. Soluble extracts from these bacteria contained a substance which competed with 125I-PDGF for PDGF receptor sites in fibroblast membranes. The receptor competition activity was correlated with the presence of the v-sis-encoded protein as assessed by genetic and immunochemical criteria. These results directly demonstrate that the v-sis oncogene product is functionally related to PDGF.