Alteration in glutathione level during carcinogenesis of hamster buccal pouch mucosa

This study examined the level of glutathione (GSH)--a tripeptide that may have an important role in detoxification of carcinogens--in the hamster buccal pouch mucosa (HBPM) by a 12-week regimen of tri-weekly topical application of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil. GSH was quantified periodically and shown to be doubled in carcinogen-treated vs. control pouch mucosa. In the tumors that developed, the level of GSH was three times that of the controls. Previous studies showed that gamma-glutamyl transpeptidase (GGT), one of the enzymes that may be responsible for the detoxification of carcinogens, was increased in the hamster mucosa pre-neoplastic foci, but decreased with the formation of overt neoplasia. GGT and GSH are intimately related, since GGT is the only enzyme that can cleave the intact GSH molecule. The increase in both GSH and GGT levels may be responsible for the increased resistance of the pre-neoplastic pouch epithelium to the toxic effects of the carcinogen.

Identification and characterization of the Poa p IX group of basic allergens of Kentucky bluegrass pollen

We reported previously the primary structure of three full-length cDNA clones that encode a new group of IgE-binding proteins of Kentucky bluegrass (KBG) pollen, designated as Poa p IX. In the present study we have further characterized the cloned Poa p IX proteins, identified the corresponding proteins in KBG pollen extract, and determined their antigenic relationships with other known grass pollen allergens. A recombinant IgE-binding polypeptide rKBG7.2 that represents the C-terminal fragment, conserved in Poa p IX proteins, appeared to contain epitopes unique to these proteins and served as an immunosorbent for the isolation of the corresponding human IgE antibodies. On two-dimensional PAGE blots these IgE antibodies bound selectively to five distinct KBG pollen proteins with molecular mass 28 to 34 kDa and isoelectric point greater than 9.5. These proteins differ in size and charge from known allergens, but are very similar to those of the recombinant Poa p IX proteins. The rKBG3.1, which represents the N-terminal region of the Poa p IX clone KBG31, as well as the corresponding natural allergens were shown to possess epitopes that crossreact with the acidic group V allergens of Timothy. Comparison of amino acid sequences of recombinant Poa p IX proteins with those of Lol p I isoallergens revealed no significant sequence similarities. In contrast, partial homology was demonstrated between the N-terminal sequences of these proteins and the Phl p V proteins. Our results confirm that the Poa p IX clones represent a distinct and major group of allergens of KBG pollen, and demonstrate structural similarities and antigenic cross-reactivities among different groups of allergenic proteins in grass pollens.

Effect of R(-)2,5-dimethoxy-4-methylamphetamine on uterine and umbilical blood flow in conscious pregnant sheep

Pregnant sheep and their fetuses were instrumented between 110 to 120 days of gestation (term, 145 days) for monitoring maternal and fetal arterial blood pressure, heart rate and blood flow in the maternal uterine and fetal intra-abdominal umbilical arteries. The administration of 2,5-dimethoxy-4-methylamphetamine (DOM, a 5-HT2 agonist) i.v. to the ewe in doses ranging from 1 to 20 micrograms/kg of ewe body weight produced dose-dependent decreases in the blood flow of the uterine and umbilical arteries. This was accompanied by an increase in the arterial blood pressure of the mother and fetus and a decrease in the fetal heart rate. DOM significantly increased the vascular resistance to blood flow in the uterine and umbilical arteries. The maximal increase in the vascular resistance of the uterine and umbilical arteries was 19.6- and 2.6-fold, respectively. Ketanserin, a 5-HT2 antagonist (1 mg/kg), administrated 30 min prior to DOM significantly inhibited the reduction in blood flow in the uterine and umbilical arteries to DOM and blocked the increased vascular resistance in these vessels. The inhibitory effects of ketanserin on the responses to DOM in the uterine and umbilical arteries were surmountable. Our results indicate that DOM is a potent constrictor of the uterine and umbilical vasculature which may lead to fetal distress as evidenced by a decrease in fetal heart rate and arterial blood PO2. 5-HT2 receptor stimulation by DOM may be involved in these effects since they were blocked by ketanserin.

[The growth and morphological characteristics of human and rabbit corneal endothelium in tissue culture]

In in-vitro culture, we have found that corneal endothelial cells exhibited membranous growth character in tissue culture. The cells were polygonal in shape. When human corneal endothelium grew in single layer, we found the phenomenon of amitosis. Scanning electronmicroscopy showed the microvilli of endothelial cells in vitro were more than in vivo. Transmission electronmicroscopy demonstrated a lot of intercellular desmosome and many fibrillar structures accumulated into bundles, curly-hair-like in shape and distributed reticularly around the nucleus. The cells were rich in organelles. We have also discussed the regenerative ability and some biological characteristics of corneal endothelium. It may be suggested that human corneal endothelia exhibit the proliferative ability in some condition. However, their proliferative form remains to be further studied.

[Mechanism of multiresistant Salmonella typhi]

From November 1988 to June 1989, 142 strains of S. typhi were isolated from patients of typhoid fever in Qingpu County, Shanghai These strains were highly sensitive to ceftazidime, ceftriaxone, ofloxacin and enoxacin, the sensitive rates to chloramphenicol, co-trimoxazole and ampicillin being from 67% to 83%. Of these 142 strains, twenty-two were multiresistant strains, being resistant to chloramphenicol, co-trimoxazole, ampicillin, cefazolin, gentamicin, piperacillin and tetracycline. Beta-lactamase production was the possible mechanism of resistance of S.typhi to beta-lactam antibiotics. Plasmid analysis by agarose gel electrophoresis showed that a plasmid band of 98Md was found in all multiresistant strains as well as the conjugates, while in sensitive strains, no plasmid band was found. The 98Md large plasmid seemed to be closely related to the multiresistance of S.typhi. Phage typing of S.typhi strains in Qingpu area revealed that M1 was the most prevalent type and A, E1, D2 etc followed in order of frequency. M1 type seemed to be closely related to the resistance to chloramphenicol, co-trimoxazole and ampicillin.

The T-cell repertoire is not dictated by self antigens alone

The influence of genetic and environmental factors on the functional cytotoxic T cell (CTL) allorepertoire was studied by comparing the CTL precursor frequencies against the same HLA alloantigens in 116 sibling pairs. A significantly different precursor frequency was found in 68%, 61% and 59% of siblings sharing 0, 1 and 2 HLA haplotypes, respectively. These data show that, although HLA is important in determining the T-cell repertoire, this is hardly reflected in the allorepertoire. Even 50% of the monozygotic twin pairs showed a significant disparity in their CTL allorepertoire, indicating that environmental factors play a role as well. The non-inherited maternal HLA antigens could be identified as one of the environmental factors shaping the CTL allorepertoire.

[Effects of apolipoproteins AI, CI, CII, CIII and E on the binding of 125I-labeled apoE-deficient HDL3 to rat liver plasma membranes]

Effects of purified human apolipoproteins AI, CI, CII, CIII-1, Cs and E on the binding of 125I-labeled apo E-deficient HDL3 to isolated rat liver plasma membranes were investigated. Unlabeled apo AI, CI, CII, CIII-1 and apo Cs, but not apo E, could effectively inhibit 125I-labeled HDL3 binding to liver membranes, apoCIII-1, was the strongest among the apoC subclasses and the inhibition curve of apoCIII-1 was similar to that of apo AI. This result indicates that apo C, especially apo CIII, may be another specific ligand of HDL receptor, and it plays an important role in regulation of HDL receptor activity in liver.

1291 cases of cholelithiasis treated with electric shock on otoacupoints

Since 1985, the authors began to use electric shock on otoacupoints of varying electric resistance for the treatment of cholelithiasis. The instrument used was the Channel Therapeutic Instrument made in China, and the otoacupoints of varying electric resistance were Sympathetic, Pancreas--Gall Bladder, Stomach, Liver, Sanjiao, Endocrine, and Ermigen. In the 1291 cases treated, the total effective rate was 99.69%, the rate of calculus excretion was 91.32%, and the rate of total excretion was 19.51%. The composition of the calculi was cholesterol crystals (31.25%), bilirubin crystals (28.17%), and mixed crystals (40.58%). The largest calculus excreted was an extrahepatic biliary duct calculus of 1.75 cm X 1.5 cm; the largest number of calculi excreted was 152 cholecystic stones 0.3 cm X 0.5 cm in size. In 100 random cases, the biliary system was shown to manifest vigorous dilations and constrictions under Ultrasonic B-scan when the relevant otoacupoints were stimulated with electric shock. Among the 78 control cases, no cholecystic stones were excreted, inspite of the Magnesium Sulfate, Folium Cassiae and fatty meals administered to many cases with constipation.

Characterization of alpha-adrenoceptors mediating contraction in isolated ovine umbilical vein

Responses to alpha-adrenoceptor agonists were studied in isolated umbilical vessels obtained from fetal lambs within 2 weeks of term (term = 145 days). Norepinephrine produced concentration-dependent contractions of the umbilical vein, but not in the umbilical artery. The contraction elicited by norepinephrine in the umbilical vein was not potentiated by cocaine (10(-5) M). Epinephrine also produced contractions of the umbilical vein with a potency similar to that of norepinephrine. Phenylephrine was less potent than norepinephrine while clonidine and xylazine were inactive in producing contractions of the umbilical vein. The dissociation constant (KA) of norepinephrine in the umbilical vein was 172 +/- 41 nM. There was little, if any, alpha-adrenoceptor reserve in the umbilical vein. Contraction produced to norepinephrine in the umbilical vein was effectively blocked by prazosin and phentolamine. Yohimbine was 500 times less potent than prazosin in blocking norepinephrine-induced contraction in the umbilical vein. Idazoxan only minimally antagonized the contractions elicited to norepinephrine. We conclude that alpha 1-adrenoceptors are present and mediate vasoconstriction in the ovine umbilical vein and that alpha 2-adrenoceptors are not present in this tissue.

HLA associations with Hashimoto's thyroiditis

There is disagreement over the HLA-DR associations of Hashimoto's (goitrous) thyroiditis. We have studied 86 English Caucasian patients with this condition whose DR types were determined by restriction fragment polymorphism analysis. HLA-DR3 was significantly more frequent in these patients than in 100 controls (chi 2 = 7.09; P less than 0.01). The relative risk was 2.23 and aetiological fraction 0.29. HLA-DPB and DQB alleles were analysed in a proportion of these subjects by enzymatic DNA amplification and oligonucleotide probing. The only significant finding was an excess of HLA-DQw2 (in linkage disequilibrium with DR3) in the Hashimoto group (chi 2 = 7.43, P less than 0.007). These results do not support a difference between goitrous and atrophic thyroiditis based on respective associations with HLA-DR5 and DR3, but confirm a recent study in which HLA-DR3 was associated with Hashimoto's thyroiditis. However, it is possible that genes telomeric to DR3 may be involved in determining which type of thyroiditis a patient with autoimmune hypothyroidism develops.

Activation of human neutrophils by Mycobacterium tuberculosis-derived sulfolipid-1

The principal sulfatide of a group of acidic lipids from virulent Mycobacterium tuberculosis, sulfolipid-1 (SL-1), stimulates neutrophil superoxide (O2-) generation and, at lower concentrations, primes neutrophil response to several other metabolic agonists including FMLP, and PMA. These responses to SL-1 were examined in relation to diacylglycerol (DAG) generation, Ca2+ availability and activation of guanine nucleotide binding proteins to clarify the signal transduction pathways involved. Pertussis toxin inhibited the ability of SL-1 to both stimulate neutrophils directly and to prime neutrophils for subsequent responses induced by PMA, suggesting a role for one or more guanine nucleotide regulating proteins in both responses. SL-1 induced a rise in neutrophil DAG levels. DAG generation was inhibited by pretreatment of cells with pertussis toxin. Depletion of extracellular Ca2+ ablated O2- release induced by stimulatory levels of SL-1 but did not inhibit the priming effect induced by substimulatory concentrations of the lipid. Investigation of the activation of the neutrophil NADPH oxidase in a cell-free system revealed that the SL-1-priming effect was associated with translocation of the soluble cytosolic factors required for activation of the enzyme. Cytosolic factor translocation was not observed in pertussis toxin pretreated cells. Our results provide evidence for the role of a guanine nucleotide binding protein in both priming and direct activation of neutrophils by SL-1. This G protein regulates both SL-1-induced DAG generation and cytosolic cofactor translocation involved in neutrophil activation and priming. The multiplicity of effects of SL-1 on signal transduction pathways leading to phagocyte activation and priming may exert a profound influence on the pathogenicity of M. tuberculosis.

Activation of human neutrophils by Mycobacterium tuberculosis-derived sulfolipid-1

The principal sulfatide of a group of acidic lipids from virulent Mycobacterium tuberculosis, sulfolipid-1 (SL-1), stimulates neutrophil superoxide (O2-) generation and, at lower concentrations, primes neutrophil response to several other metabolic agonists including FMLP, and PMA. These responses to SL-1 were examined in relation to diacylglycerol (DAG) generation, Ca2+ availability and activation of guanine nucleotide binding proteins to clarify the signal transduction pathways involved. Pertussis toxin inhibited the ability of SL-1 to both stimulate neutrophils directly and to prime neutrophils for subsequent responses induced by PMA, suggesting a role for one or more guanine nucleotide regulating proteins in both responses. SL-1 induced a rise in neutrophil DAG levels. DAG generation was inhibited by pretreatment of cells with pertussis toxin. Depletion of extracellular Ca2+ ablated O2- release induced by stimulatory levels of SL-1 but did not inhibit the priming effect induced by substimulatory concentrations of the lipid. Investigation of the activation of the neutrophil NADPH oxidase in a cell-free system revealed that the SL-1-priming effect was associated with translocation of the soluble cytosolic factors required for activation of the enzyme. Cytosolic factor translocation was not observed in pertussis toxin pretreated cells. Our results provide evidence for the role of a guanine nucleotide binding protein in both priming and direct activation of neutrophils by SL-1. This G protein regulates both SL-1-induced DAG generation and cytosolic cofactor translocation involved in neutrophil activation and priming. The multiplicity of effects of SL-1 on signal transduction pathways leading to phagocyte activation and priming may exert a profound influence on the pathogenicity of M. tuberculosis.

Ion-implanted Nd:MgO:LiNbO(3) planar waveguide laser

Laser oscillation in an ion-implanted planar Nd:MgO:LiNbO(3) waveguide is demonstrated for the first time to our knowledge. Details of the waveguide structure, spectroscopic properties, photorefractive effects, and laser performance are given. A simple calculation of the absorbed power threshold gives ~8 mW, in fair agreement with the experimental value of ~17 mW.

Comparison of the humoral and cytotoxic T-lymphocyte response to individual HLA class I alloantigens in highly immunized patients

In order to investigate the correlation between activation of cytotoxic T-lymphocyte precursor (CTLp) and the formation of antibodies to alloantigens, we studied 21 highly sensitized patients waiting for a kidney transplantation. Both antibody reactivity and CTLp frequencies of these patients were determined against 88 individual HLA class I alloantigens. A high or low CTLp frequency against a certain HLA-A or -B alloantigen was not correlated with the presence or absence of the antibodies to that antigen. Mismatched antigens, towards which the patient had not formed antibodies, can induce either a higher or a lower frequency of CTLp compared to mismatches towards which the patients had formed antibodies. The possible implications of this lack of correlation between the T- and B-cell allorepertoires with regard to donor selection for (highly immunized) patients is discussed.

[Microwave processing method of semen Armeniacae Amarum]

This paper reports the microwave processing method of Semen Armeniacae Amarum (Prunus armeniaca var. ansu). The experimental results showed that amygdalase was completely inactivated and the contents of amygdaloside were not reduced at all. The time and temperature of the processing method have also been studied.

5-HT2 receptor-stimulated calcium influx in ovine uterine artery in late pregnancy

The effects of 5-hydroxytryptamine (5-HT) and 2,5-dimethoxy-4-methyl-amphetamine (DOM) on the Ca2+ influx in the ovine uterine artery in late pregnancy have been studied by measuring 45Ca2+ uptake. Both 5-HT and DOM (2.5 x 10(-8) M to 2.5 x 10(-5) M) induced concentration-dependent rises in 45Ca2+ uptake in the ovine uterine artery, from a basal level of 30.5 +/- 3.5 muMoles/kg wet tissue to peak levels of 91.1 +/- 9.2 and 84.2 +/- 8.1 muMoles/kg wet tissue, respectively. The Ca2+ influx evoked by 5-HT and DOM was inhibited by ketanserin in a concentration-dependent manner. Methiothepin (2.5 x 10(-7) M) also inhibited 5-HT-induced (2.5 x 10(-6) M) Ca2+ influx by 86%. No antagonism was found with 2.5 x 10(-6) M of 3-tropanyl-3,5-dichlorobenzoate (MDL 72222). The contraction elicited to 5-HT (10(-6) M) and DOM (10(-6) M) was blocked by D600 (10(-6) M) which also blocked the contraction produced to KCl (9 x 10(-2) M). Amrinone (10(-5) M) had no inhibitory effect on these contractions. In accord with the results of the contraction study, D600 (2.5 x 10(-6) M) blocked the Ca2+ influx stimulated by 5-HT (2.5 x 10(-6) M) and amrinone (2.5 x 10(-5) M) failed to inhibit 5-HT-induced Ca2+ influx. Nifedipine (2.5 x 10(-6) M) did not antagonize the influx of Ca2+ induced by 5-HT. Sodium nitroprusside inhibited the 5-HT-induced Ca2+ influx, indicating that at least part of its inhibitory effect on the vasoconstriction evolved by 5-HT is due to the inhibition of the influx of Ca2+.

Anoxic block of GABAergic IPSPs

In rat hippocampal slices GABAergic IPSPs are very rapidly suppressed by anoxia (in less than 2 min). Both early (GABAA) and late (GABAB) components are affected. After reoxygenation, the IPSPs recover, but only slowly and not always completely. Iontophoretic applications of GABA or baclofen indicated no major depression of responses during anoxia. It is therefore unlikely that the anoxic suppression of IPSPs is caused by desensitizations of GABA receptors. A more probable explanation is a failure of GABAergic neurons to release GABA from inhibitory nerve terminals.

[Chlamydia trachomatis immunotypes in trachoma epidemic areas of north China]

The distribution of various immunotypes of C. trachomatis in epidemic areas of North China was studied by the micro-immunofluorescence (Micro-IF) test of tears and sera from 104 patients with trachoma. IgG antibody to C. trachomatis was positive in 64 cases, and the immunotypes were type B (78.1%) and type C (21.9%). The TE-55 strain determined as type I in 1966 was confirmed to be type C. The Micro-IF test that quantitated antichlamydial IgG antibody in tears was compared with ELISA in the detection of C. trachomatis in 59 individuals. The sensitivity and specificity of the Micro-IF test were 91.5% and 100% respectively.

Involvement of 5-HT1A activity in the discriminative stimulus effects of imipramine

Pigeons were trained to discriminate the tricyclic antidepressant imipramine (3.0 or 5.6 mg/kg) from saline. The selective 5-HT1A agonist 8-OH-DPAT (0.03-1.0 mg/kg) resulted in dose-dependent increases in responding on the key correlated with imipramine administration. Doses of 8-OH-DPAT from 0.3 to 1.0 mg/kg substituted completely for imipramine. NAN-190 (0.3-3.0 mg/kg), a putative 5-HT1A antagonist with affinity for both 5-HT1A and alpha 1 receptors, blocked the discriminative stimulus effects of imipramine and resulted in saline-key responding. The discriminative stimulus effects of imipramine were also blocked by administration of the alpha 1-adrenoceptor antagonist prazosin, suggesting a dual mediation of imipramine through both 5-HT1A and alpha 1-adrenoreceptor systems. Although antidepressants have not been used frequently as stimuli in drug discrimination studies, it may be possible to arrive at a more complete understanding of their neurochemical and behavioral effects using this procedure.

Effects of 5-hydroxytryptamine on cat spinal motoneurons

The effects of 5-hydroxytryptamine (5-HT) on spinal motoneurons were examined in pentobarbital-anaesthetized cats and in nonanaesthetized decerebrate cats by intracellular recording and extracellular iontophoresis of 5-HT. 5-HT first induced a depolarization and then a long-lasting hyperpolarization (up to 60 min) with unchanged input resistance. The slow hyperpolarization was prevented by the 5-HT antagonists ketanserin (5-HT2), methysergide, and spiperone (5-HT1,2) and mimicked by the agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (5-HT2). The post-spike after hyperpolarization was enhanced after application of 5-HT. A depolarization was induce by the 5-HT agonists (+/-)-8-hydroxy-(2)-(di-n-propylamino)tetralin (5-HT1A) and 1-(2-methoxyphenyl)piperazine (5-HT1). Possible mechanisms for the 5-HT-induced hyperpolarization and its intracellular medication are discussed. The present data suggest multiple effects of 5-HT on cat spinal motoneurons.

[Effects of schizandrol A on monoamine neurotransmitters in the central nervous system]

Schizandrol A (2',3',4',1",2",3"-hexamethoxy-6, 7-dimethyl-1,2,3,4-dibenzo-1,3-cyclooctadien-6-ol) is one of the effective components in the dried fruit of Schizandra chinensis Bail. Previous studies have found that schizandrol A exerts inhibitory effects on the central nervous system (CNS). For the purpose of elucidating the mechanism of inhibition, the concentrations of monoamine neurotransmitters and their metabolites in rat brain and the effects of schizandrol A on some receptors were determined by the ion-pairing reversed-phase liquid chromatography with electrochemical detection method and competitive binding assay. In the neurotransmitter studies, significant elevations of dopamine and its metabolite DOPAC (in striatum) and DA (in hypothalamus) were observed after i.p. administration of 50 mg/kg or 100 mg/kg of schizandrol A. But the receptor binding experiments showed that schizandrol A had no affinity for dopamine D1 and D2 receptors. Serotonin receptors and alpha 1-,alpha 2-adrenergic receptors, and it did not affect the binding of dopamine to dopamine D1 or D2 receptors. These results indicate that the inhibition exerted by schizandrol A on the CNS may be related to the dopamine system, and the increase of dopamine turnover has nothing to do with dopamine receptors. The concentrations of the norepinephrine metabolite MHPG and the serotonin metabolite 5-HIAA showed changes in rat striatum and hypothalamus after schizandrol A treatment, but norepinephrine and serotonin levels were unaffected.

Helper virus-dependent replication, nucleotide sequence and genome organization of the satellite virus of maize white line mosaic virus

Virus like particles (17 nm in diameter) associated with maize white line mosaic virus (MWLMV) were shown to be a satellite virus of MWLMV (SV-MWLMV) on the basis of the following properties: (1) The SV-MWLMV was dependent upon the presence of MWLMV for replication in maize, while the latter virus could replicate independently of the SV particles. (2) No nucleotide sequence homology was detected between the SV-MWLMV and MWLMV, using complementary DNA probes prepared to the two RNAs, in a Northern blot hybridization analysis. (3) The RNA of the SV-MWLMV translated in vitro to produce a protein of the same Mr (24,000) as that found associated with the SV particles. This protein could be immunoprecipitated with an antiserum to the SV particles. And (4), there was no serological relationship between the coat proteins of MWLMV and the SV-MWLMV. The complete nucleotide sequence of the SV-MWLMV RNA (1168 nucleotides) was determined. The SV-MWLMV RNA contains a single open reading frame encoding a polypeptide of Mr 23,961. Computer analysis revealed no significant homology between SV-MWLMV RNA and any other viral or satellite RNAs. However, the putative SV-MWLMV capsid protein is predicted to share some structural features with the capsid protein of the satellite virus of panicum mosaic virus.

Nucleotide sequence analysis of three cDNAs coding for Poa p IX isoallergens of Kentucky bluegrass pollen

Grass pollen allergens are one of the major causes of type I allergic reactions (allergic rhinoconjunctivitis, allergic bronchial asthma, and hayfever) in temperate climates afflicting 15-20% of a genetically predisposed population. Workers have found considerable physico- and immunochemical heterogeneity within the grass pollen allergens which has made them difficult to purify for both therapeutic uses and further biochemical study. We recently reported the construction of a cDNA library in lambda gt11 using mRNA extracted from dehydrated Kentucky bluegrass (KBG, Poa pratensis). Here, we present the nucleotide and deduced amino acid sequences for three KBG pollen allergen cDNA clones, KBG 41, 60, and 31, which were isolated from the above library using a pool of six sera from grass pollen allergic patients. These clones exhibit an exceptionally high degree of sequence similarity to one another, only minor similarity to other known allergens, and no homologies to other known proteins or genes. The predicted molecular mass for the cloned proteins range from 28.3 to 37.8 kDa with pI values of 9.6-10.2. All three clones appear to possess leader peptides and lack asparagine sequons required for N-glycosylation. Therefore, the molecular mass of the post-translationally modified proteins were calculated to be 28.4-34.9 kDa, which is consistent with the size of the polypeptides revealed in Western blots of pollen proteins using an antiserum to a recombinant peptide encoded by the partial cDNA clone KBG 8.3. Northern blotting analysis indicates that expression of the genes corresponding to these clones is confined to pollen tissue. The results suggest that the clones code for a group of proteins that represent a new and previously uncharacterized group of grass pollen isoallergens, which have been hereby designated as Poa p IX.

[Gelatin matrix for corneal epithelial cell cultures]

A simple and convenient gelatin matrix was prepared for epithelial cell cultures. Addition of fibronectin, laminin or fibrinogen enhanced the attachment and growth of corneal epithelial cells in vitro.

Accurate control of contrast on microcomputer displays

Off-the-shelf microcomputers can now display arbitrary 8-bit images, but accurate control of these images requires dealing with several undesirable properties of real digital to analog converters (DACs) and analog video monitors. The limitations of DACs and video monitors are presented in the form of a model for their calibration and use in vision experiments. Low contrasts can be accurately rendered by summing a small accurate a.c. signal and a large less-accurate d.c. signal (Watson et al., 1986; Behavior Research, Method, Instrument and Computers, 18, 587-594). Exploiting that idea, this note presents an easy-to-build passive resistor network, a video attenuator, that combines the outputs of three 8-bit DACs to render low contrasts with 12-bit accuracy at the display. Measurements confirm the 12-bit accuracy.

Amplitude change with click rate in human brainstem auditory-evoked responses

The effect of click rate on wave amplitude of human brainstem auditory-evoked response (BAER) was examined at repetition rates of 10, 30, 50, 70 and 90 Hz in 80 healthy children aged 1 month to 6 years and in 21 adults. As repetition rate was increased from 10 to 90 Hz at 70 dB HL, the amplitudes in different age groups decreased by 33-45% (0.109-179 microV) for wave I and 25-41% (0.055-0.145 microV) for wave V. The older the children, the larger the absolute decrements of wave amplitudes with increasing repetition rate, but the relative decrements or reduction rates of wave amplitudes exhibited no systematically age-related differences. The V/I amplitude ratio tended to increase with increasing repetition rate in most age groups, suggesting that the amplitude of wave I is affected by the repetition rate slightly more than that of wave V. The patterns of the changes in wave amplitudes with repetition rate at lower intensity levels were essentially similar.

Optical implementation of a second-order neural network

An optical implementation of a single-layer, second-order neural network is presented. The quadratic products are obtained by passing the optical beam twice through the input ferroelectric liquid-crystal (FLC) spatial light modulator (SLM), with the interconnection weights being implemented by a further two-dimensional 128 x 128 FLC SLM. The machine successfully associates eight randomly chosen pattern-target pairs (dimensions 16 and 4, respectively) and can learn the parity association. Translation invariance is also demonstrated. Results from a computer model indicate that input SLM contrast ratios of 4:1 and electronic noise of 10% of the maximum output can be tolerated.

Allergenic and antigenic cross-reactivities of group IX grass pollen allergens

The allergenic and antigenic cross-reactivities between a major recombinant Poa pratensis (Poa p) IX allergen, rKBG8.3, and its corresponding proteins of different grass pollens were examined. Immunoblotting of the proteins of thirteen different grass pollens using anti-rKBG8.3 antibodies indicated that Poa p IX-like proteins are present in ten other grass pollens, albeit in variable amounts and polymorphic forms. These proteins ranged in size from 20 to 88 kDa in different grass pollens. The percent relative binding determined for each grass pollen extract using allergic human sera showed a significant correlation (r = 0.891) with that of anti-rKBG8.3 antiserum. Moreover, there was a strong association (r = 0.901) between the Kentucky bluegrass extract and rKBG8.3 with respect to their inhibition of the binding of human IgE antibodies to allergens in grass pollen extracts. Taken together, these results suggest that the allergenic and antigenic epitopes of the Poa p IX-related proteins in some but not all grass pollens are similar in structure and specificities. It is concluded that the group IX allergens constitute a major family of homologous proteins in several grass pollens.

Simultaneous comparison of pre- and post-microanastomotic hemodynamic profiles using a Tandem Doppler Probe

The use of High-Frequency Pulsed Doppler Ultrasound (HFPDU) for evaluation of microvascular hemodynamics is well established. Due to technical limitations of existing probes, quantitation of anastomotic stenoses and detailed waveform analyses are difficult to perform and impractical for clinical use. We present a new Tandem Doppler Probe (TDP) for simple and accurate study of blood flow in vessels smaller than 1 mm in diameter. Its unique ability to compare the pre- and post-anastomotic waveforms simultaneously allows for quantitative detection of anastomotic narrowing of as little as 5%, as well as identification of subtle pathologic anastomotic waveform changes not seen with single probes. Such early and precise delineation of anastomotic problems in the operating room can provide an invaluable, objective assessment of the technical adequacy of the anastomoses as well as an important baseline for later post-operative monitoring of free-tissue transfers with implantable Doppler devices.

A new technique for microvascular sleeve anastomosis

This study describes our experience using an improved technique for microsurgical sleeve anastomosis of arteries. Modifications of previously described techniques include utilization of a sidecut and placement of the two stitches within separate vertical planes. In 40 arteries, we attained a patency rate of 97.5%. Histology, in vivo observation, and flow study using high-frequency pulsed ultrasound Doppler at 2 hr to 8 weeks demonstrate that the sidecut sleeve anastomosis shows patency and flow characteristics similar to those of standard end-to-end anastomosis, but with a dramatic decrease in operative time.

The hypoxic stress on erythrocytes associated with superoxide formation

Superoxide is produced during the autoxidation of hemoglobin. Autoxidation of hemoglobin is, however, facilitated under hypoxic conditions where hemoglobin is only partially oxygenated. We have recently found that the erythrocyte superoxide dismutase does not fully react with the additional superoxide produced under hypoxic conditions. A leakage of superoxide from the erythrocyte is thus detected, resulting in a potential source for oxyradical damage to tissues. Detailed studies on intact erythrocytes as a function of oxygen pressure have now been performed. These studies further delineate the hypoxic stress on erythrocytes and the mechanism for the leakage of superoxide. By centrifugation of samples under various oxygen pressures it was possible to show an enhanced rate of lysis at reduced oxygen pressures with a maximum rate in the region of 25 mm Hg. At much lower pressures where the hemoglobin is mostly deoxygenated the rate of lysis was dramatically decreased with almost no lysis detected even after three days. Lysis is shown to be associated with superoxide membrane damage. The formation of superoxide which does not react with endogenous SOD reaches a maximum value at much lower pressures where most of the hemoglobin is deoxygenated. It is suggested that the leakage at low pressure is associated with the formation of superoxide by oxidation of hemoglobin associated with the membrane.

A gamma-carboxyglutamic acid (gamma) variant (gamma 6D, gamma 7D) of human activated protein C displays greatly reduced activity as an anticoagulant

Site-specific mutagenesis has been employed to alter the cDNA of human protein C (PC), such that the gamma-carboxyglutamic acid (gamma) pair at positions 6 and 7 of the recombinant (r) protein would be changed to aspartic acid residues. This variant, [gamma 6D, gamma 7D]r-PC, and its wild-type (wt) counterpart have been expressed in human kidney 293 cells. After purification, forms of wtr-PC that were fully gamma-carboxylated and beta-hydroxylated and of [gamma 6D, gamma 7D]r-PC that lacked only the two altered gamma-residues at amino acid sequence positions 6 and 7 were obtained. Subsequent to its conversion to activated PC (APC), [gamma 6D, gamma 7D]r-APC displayed a greatly reduced activity in the activated partial thromboplastin time of PC-deficient plasma, as compared to wtr-APC and human plasma APC. In addition, the activity of [gamma 6D, gamma 7D]r-APC toward inactivation of purified human factor VIII was reduced to less than 5% of that of wtr-APC and human plasma APC. These results, with the first reported mutations at gamma-residues of PC produced by recombinant DNA technology, indicate that the paired gamma-residues at positions 6 and 7, which are highly conserved in all vitamin K dependent coagulation proteins, are very important to generation of fully functional APC. Additional results demonstrate further that lack of gamma-carboxylation at positions 6 and 7 of PC does not substantially affect this same processing reaction at other relevant glutamic acid residues.

The effect of individual HLA-A and -B mismatches on the generation of cytotoxic T lymphocyte precursors

In order to study the correlation between HLA mismatches and the cytotoxic T lymphocyte precursor frequency, we used a limiting dilution analysis to determine the CTLp frequencies against individual mismatched HLA-A and -B alloantigens in 21 patients waiting for a renal transplant. Altogether, thirty-three mismatched HLA-A antigens and 55 HLA-B antigens were tested. The CTLp frequencies against mismatches of HLA-B locus antigens were found to be significantly higher than those against HLA-A antigens (P less than 0.002). This may explain why matching for HLA-B antigens is more important for a good renal allograft survival than matching for HLA-A antigens.

Post-translational modification of a monocyte-specific chemoattractant synthesized by glioma, osteosarcoma, and vascular smooth muscle cells

Chemotaxis is an important step in monocyte recruitment in inflammation, wound healing, and tumor growth. We reported previously that monocyte chemotactic activity secreted by malignant cells and normal smooth muscle cells is associated with a protein or family of proteins that are related to the monocyte-specific smooth muscle cell-derived chemotactic factor (SMC-CF) (Graves, D. T., Jiang, Y. L., Williamson, M. J., and Valente, A. J. (1989) Science 245, 1490-1493). Similar monocyte chemotactic proteins (MCP-1) produced by U-105MG human glioma cells have also been identified (Yoshimura, T., Robinson, E. A., Tanaka, S., Appella, E., Kuratsu, J., and Leonard, E. J. (1989) J. Exp. Med. 169, 1449-1459). We now report that the MCP-1 gene is expressed in MG-63 human osteosarcoma and vascular smooth muscle cells and that SMC-CF antiserum specifically immunoprecipitates proteins synthesized by U-105MG glioma cells. Experiments were undertaken to elucidate the processing pathway of MCP-1/SMC-CF-like proteins in each of these cell types. These experiments demonstrate that larger MCP-1/SMC-CF-like proteins are derived from a Mr = 9000 precursor. Post-translational modification involves the addition of O-linked carbohydrates and sialic acid residues. Differences in carbohydrate processing account for the heterogeneity in MCP-1/SMC-CF-like proteins produced by different cell types. Secretion of these proteins occurs rapidly following processing events in the endoplasmic reticulum-Golgi compartment.

[Establishment of standard strains of serotypes (groups) of Streptococcus pneumoniae in China]

Streptococcus pneumoniae is an important human pathogen which is responsible for life-threatening infections such as pneumonia, bacteremia and meningitis as well as for less severe but highly prevalent diseases such as otitis media and sinusitis. The number of serogroups (types) of Streptococcus pneumoniae found in the world is total 46 groups or 83 types according to typing system of Statens Serum Institute, Copenhagen, Denmark. The standard strains established in our lab of 42 groups or 67 types distributed in 17 different regions in China. The significance of this study is that two of the new serotypes (10C, 16A) are first reported in the literature in which the microbes were the agents causing pneumococcal infections. Our standard strains also include some serotypes on rare occasions such as 19C and 22A and 33C which have been found only in Asia. Our findings not only increase the total number of known types of pneumococci from 83 to 85, but also indicate that China has made progress in the field of pneumococcal research. It is the first time to report establishing a series of standard strains of pneumococci involving many serotypes (groups) in China. The work is necessary as a preliminary for pneumococcal disease prevention and treatment. The standard strains listed here with providing the resource of strain and scientific basis for developing vaccine and biological products.

Relation between plasma atrial natriuretic peptide (ANP) and glomerular ANP receptors in 5/6 nephrectomized rats

Chronic renal failure (CRF) was induced in male wistar rats (Group I) by 5/6 nephrectomy and the sham-operated ones served as control (Group II). The results showed that in Group I, plasma atrial natriuretic peptide (ANP) levels increased progressively as the Scr was elevated. Plasma R-A rose simultaneously compared to the normal (P less than 0.001). At the 20th week after operation, urine volume and Na decreased significantly (P less than 0.05). The number of glomerular receptors decreased markedly at the 12th week (P less than 0.05) and 20th week (P less than 0.01). Our data suggest that in 5/6 nephrectomized rats, the elevation of plasma ANP level might be partly caused by the damage of glomerular ANP receptors, and the elevated plasma ANP could not play its role in diuresis, natriuresis, blood pressure depression and R-A inhibition as a result of the damage of kidney ANP receptors.

Whole-cell patch study of GABAergic inhibition in CA1 neurons of immature rat hippocampal slices

Inhibitory processes mediated by gamma-aminobutyric acid (GABA) were studied in immature rat hippocampal slices using the whole-cell patch clamp technique. Orthodromically evoked hyperpolarizing inhibitory postsynaptic potentials (IPSPs) were observed in CA1 neurons of postnatal 2-5 (P2-5) and 7-13 (P7-13) day old rats under conditions of low internal [Cl-]. In the whole-cell voltage-clamp mode, applications of GABA evoked outwards currents which reversed at -55 mV and -62 mV in P2-5 and P7-13 CA1 neurons, respectively, with comparable reversal potential for the IPSPs for each age. An increase in internal [Cl-] caused a depolarizing shift of the GABA reversal potential which followed the Nernst equation. In both groups of neurons, the IPSPs and GABA currents were blocked with the bath applications of bicuculline (10 microM) and picrotoxin (100 microM). We conclude that the GABAA-mediated inhibitory synaptic process exists in P2-5 CA1 neurons and hypothesize that the absence of such IPSPs noted in previous studies of immature CA1 neurons was likely due to higher internal [Cl-] in the more immature neurons.

Potential of hypertonic medium treatment for embryo micromanipulation: II. Assessment of nuclear transplantation methodology, isolation, subzona insertion, and electrofusion of blastomeres to intact or functionally enucleated oocytes in rabbits

The objective of this research was to study efficiency of embryo development following transfer of blastomeres into the perivitelline space of oocytes. Single blastomeres from 8-, 16-, and 32-cell embryos were obtained following mucin coat and zona pellucida removal by combined treatments with pronase and acidic phosphate-buffered saline (PBS, pH = 2.5). Blastomeres were separated by pipetting with a fire-polished micropipette following incubation in Ca+(+)-free PBS for 15 min at 39 degrees C. This procedure resulted in over 97% blastomere separation. For ease of blastomere insertion, oocytes were placed in droplets of 0.5 M sucrose in PBS (SPBS) during micromanipulation. To functionally enucleate oocytes some were stained with Hoechst 33342 DNA stain and irradiated. A single 8- or 16-cell blastomere was aspirated into an injection pipette (35 microns or 25 microns at the tip, respectively) and inserted into the perivitelline space of an irradiated or non-irradiated oocyte, but not fused with the oocyte. This micromanipulation procedure did not affect development of individual blastomeres into blastocysts or trophectoderm vesicles when compared with cultured control single blastomeres (P greater than .05). When the inserted blastomere was induced to fuse with an intact non-irradiated oocyte under an electric field, 56-57% were fused and 39-45% of the fused and activated oocytes developed to morulae or blastocysts. When an inserted blastomere (from 8-32-cell embryos) was induced to fuse with a functionally enucleated oocyte treated by Hoechst 33342 staining, followed by washing and UV-light irradiation, 63-66% of them were fused, but only 15-22% developed to the morula or blastocyst stage. This research demonstrated that the use of hypertonic medium treated oocytes greatly improved the ease and success rate of blastomere subzona insertion, but the value of functionally enucleated oocytes as recipient cells for nuclear transfer requires further investigation.