[Observation of chromosome aberration and micronucleus formation in peripheral blood lymphocytes among cigarette smokers]

Using two interrelated observation indices--chromosomal aberration and micronucleus analysis in peripheral blood lymphocytes to reflect damages of genetic material, were used to observe the status of genetic material damage in male smokers at the same time. The results showed that there were significant increases in hyperpolid cell rate, chromatid and chromosome aberration rates, total aberant cell rate and frequency of micronucleated cells as well as micronucleus in smoking group when compared to non-smoking group. This findings showed that cigarette smoking is one of the important mutagenic factors which caused damage to human genetic materials.

Effect of acidosis on contraction, intracellular pH, and calcium in the newborn and adult rabbit aorta

This study investigated the effect of acidosis on intracellular pH (pHi), intracellular calcium concentration ([Ca]i), and vascular contraction in the aorta of the newborn and adult rabbit. Isometric tension, pHi, and [Ca]i were measured in an isolated ring preparation. After the vascular contraction was induced with 50mM KC1, the effect of respiratory acidosis produced by elevation of PCO2 was studied. Respiratory acidosis caused a transient depression followed by a recovery of contractile tension. The decrease in developed tension was greater in the newborn than in the adult. The decrease in pHi during acidosis was similar in the two age groups. [Ca]i increased during acidosis and the increase was greater in the newborn than in the adult. These data show that the vasorelaxant effect of acidosis in the newborn aorta is greater than that in the adult aorta. The greater vasodilation in the newborn cannot be explained by the difference in pHi or [Ca]i.

[Study of the effects of pulse magnetic fields on hemorrheology of human body]

The results show that middle shear specific viscosity and reductive viscosity (P<0.05), low shear specific viscosity and reductive viscosity of whole blood (P<0.01) decreased significantly in experimental group after 9-day of pulse magnetic fields, comparing with control group, high shear specific viscosity, low shear reductive viscosity (P<0.05) and middle and low shear specific viscosity (P<0.01) of whole blood in experimental group were lower after exposed than before exposed to pulse magnetic fields. The results suggest that the pulse magnetic fields may reduce specific and reductive viscosity of whole blood in human body.

Developmental changes in the contractile system of the mesenteric small artery of rabbit

This study investigated developmental changes in the contractile system of the mesenteric small arteries of the rabbit. Arteries about 1 mm in length and 100-250 microns in internal diameter were dissected out from the mesenteric bed of the fetus (29 d of gestation), newborn (3-5 d old), and adult rabbit. Vascular contraction was induced by high KCl concentration, and contractile force was measured using a tension transducer. The sensitivity of vascular contraction to high KCl was similar in the three age groups. To determine the role of Ca influx across the sarcolemma in vascular contraction, the vasorelaxant effect of diltiazem was studied in the artery precontracted with high KCl concentration. The vasorelaxant effect of diltiazem in the fetus and newborn was less than in the adult. To estimate the size of the intracellular Ca pool, caffeine-induced and noradrenaline-induced contraction were measured in the Ca- and Na-free solution. In the fetus and newborn, both the caffeine-induced contraction and noradrenaline-induced contraction were greater than in the adult. The ultrastructural study showed that the endoplasmic reticulum was abundant in the fetus and newborn, and it was scarce in the adult. These data indicate that the dependency of vascular contraction on Ca influx across the sarcolemma increases and the intracellular Ca store decreases with development in the mesenteric resistance arteries.

H-ras transfection of the rat kidney cell line NRK-52E results in increased induction of c-fos, c-jun and hsp70 following sulofenur treatment

The effect of the antineoplastic drug sulofenur on the induction of the immediate-early genes (IEG) c-fos and c-jun and the stress gene hsp70 was compared in the rat kidney epithelial-like cell line NRK-52E and a derivative H-ras-transfected (H/1.2NRK-52E) cell line. Fold induction for each gene after sulofenur (500 microM) treatment was greater in H/1.2NRK-52E. The maximum increases for NRK-2E and H/1.2NRK-52E were as follows: c-fos, approximately 10-fold and approximately 18-fold; c-jun, approximately 2.5-fold and approximately 3.6-fold; hsp70, approximately 13-fold and approximately 30-fold. In cells loaded with EGTA/AM or treated in low or no Ca2+ HBSS, c-fos induction was reduced similarly in both cell types. However, inhibition of protein kinases with staurosporin and calphostin C reduced c-fos by 80% in NRK-52E but by only 10-20% in H/1.2NRK.52E. These results indicate that sulofenur-induced IEG elevation is Ca(2+)-dependent and that the requirement for protein kinase C activation is bypassed in H-ras-transfected cells.

Effect of acidosis on contraction, intracellular pH and calcium in the rabbit mesenteric small artery

The purpose of the present study was to determine the effect of various types of acidosis on vessel diameter, intracellular pH (pHi), and calcium concentration ([Ca2+]i) in a cannulated preparation of the mesenteric arteriole of the rabbit. The effect of acidosis on vessel contraction was also studied in the wire-mounted preparation. In the cannulated preparation, pre-contracted by noradrenaline, hypercapnia caused vasoconstriction and increases in [Ca2+]i. In the wire-mounted preparation pre-contracted by either noradrenaline or high KCl, hypercapnia caused a transient vasoconstriction. In contrast, in the cannulated preparation pre-contracted by high KCl, hypercapnia caused a transient vasorelaxation and decreases in [Ca2+]i. Intracellular acidosis, induced by a NH4Cl prepulse, caused vasoconstriction and increases in [Ca2+]i even in the cannulated preparation pre-contracted by high KCl. The decrease in pHi during hypercapnia was similar to that observed after NH4Cl withdrawal. These data suggest that: (1) the effect of acidosis on vascular tone and [Ca2+]i is different depending upon the type of preparation and the mode of pre-activation, and (2) [Ca2+]i may, at least partly, regulate vascular contraction and relaxation during acidosis.

A clinical study on severe hydroa vacciniforme

OBJECTIVE

To describe a severe type of hydroa vacciniforme (HV) in order to provide basis for treatment and prevention of this disease.

METHODS

Nine cases of HV were collected in our outpatient department, and clinical and laboratory examinations were performed.

RESULTS

All the cases had erythemas, papules, bullae, erosions or ulcers on exposed sites, with recurrences, gradually resulting in deformation. Five patients suffered from hand deformation manifesting rigidity, flexor tetanus, or malposition of the first, second and third interphalangeal joints of hands. Two of the above mentioned patients manifested partial bone absorption of fingers. Five patients showed partial defect of auricle. Two patients showed saddle nose, and partial absorption of nasal cartilage. One patient displayed cicatricial contracture of lower lip, with incisor extrusion. Four patients showed opacity of cornea. Through laboratory examinations, porphyrinopathies were excluded. Phototests showed increased sensitivity to ultraviolet-A radiation (UVA).

CONCLUSIONS

Based on the clinical features and laboratory examinations, these patients were diagnosed as having severe HV. It is believed that this condition belongs to a disease spectrum induced by ultraviolet light. Our analysis suggests that for children with severe type of HV, preventive measures and therapeutic agents should be taken as soon as possible in order to avoid deterioration of the disease and malformations.

Characterization and localization of adrenal nicotinic acetylcholine receptors: evidence that mAb35-nicotinic receptors are the principal receptors mediating adrenal catecholamine secretion

Adrenal chromaffin cells contain at least two subtypes of nicotinic acetylcholine receptors (nAChRs). These studies were designed to identify and characterize the subtype of nAChR mediating adrenal catecholamine release using the monoclonal antibody mAb35, which recognizes the alpha-subunit of muscle nAChRs and cross-reacts with some neuronal nAChRs. Immunocytochemical studies demonstrated that mAb35 interacts with specific sites on cultured chromaffin cells. Pretreatment with mAb35 reduced nAChR-stimulated catecholamine release (IC50 of approximately 10nM). mAb35 had no effects on release stimulated through non-nAChR mechanisms. Unlike agonist-induced nAChR desensitization, the mAb35-induced reduction in nAChR-mediated secretion developed slowly. Although not immediately reversible, nAChR-stimulated release recovered after mAB35 removal. However, unlike recovery from agonist pretreatment, recovery from mAb35 pretreatment was relatively slow and was par tially blocked by vinblastine. Hybridization of adrenal chromaffin RNA with a rat alpha3 cDNA revealed two strong bands and two fainter bands: two higher-molecular-weight bands, 6.9 and 8.5 kb; a strong band of 3.2 kb; and a lower amount of 2.3kb RNA. With recovery of nAChR function after agonist or mAb35 treatment, no significant effects on alpha 3 subunit mRNA levels were seen. In summary, these studies demonstrate the presence of mAb35-nAChRs on adrenal chromaffin cells and provide evidence that these receptors represent the major population that regulates secretory events in adrenal chromaffin cells.

Rearrangement-enhancing element upstream of the mouse immunoglobulin kappa chain J cluster

Transcriptional regulatory elements have been shown to be necessary but not sufficient for the developmental regulation of immunoglobulin gene rearrangement in mouse precursor B cells. In the chicken lambda light chain locus, additional elements in the V-J intervening sequence are involved in negative and positive regulation of rearrangement. Here, mutation of the mouse homolog of a chicken element, located in the V(K)-J(K) intervening sequence upstream of the J(K) cluster, was shown to significantly decrease rearrangement. This cis-acting recombination-enhancing element affects the rearrangement process without being involved in regulating transcription.

[Inferior mesocaval shunt]

The results of inferior mesenteric vein-inferior vena cava shunt coupled with splenectomy and gastroesophageal devascularization in 16 patients with cirrhotic portal hypertention were reviewed. The mean diameter of the shunt stoma was 6.46 +/- 0.78 mm, and the portal pressure decreased from 4.25 +/- 0.54 kPa to 3.39 +/- 0.41 kPa. Variceal bleeding stopped in all 16 patients with no severe postoperative complications. This procedure should preserve satisfactory portal perfusion to the liver, and technically is easier than other shunt procedures.

Phospholipase D is activated by G protein and not by calcium ions in vascular smooth muscle

We assessed the sensitivity of phospholipase D (PLD) activity in vascular smooth muscle to cytosolic Ca2+ by increasing cytosolic Ca2+ levels independently of agonist stimulation. When rat tail artery was preloaded with the Ca2+ indicator fluo 3 pentaacetoxymethyl ester, the addition of high extracellular K+, caffeine, or norepinephrine rapidly enhanced cytosolic Ca2+ levels. Neither increased extracellular K+ nor caffeine addition increased phosphatidylethanol production, indicating that cytosolic Ca2+ elevation alone did not stimulate PLD. In contrast, norepinephrine stimulated phosphatidylethanol production in this tissue. In strips of tail artery permeabilized with alpha-toxin and incubated in solutions containing free Ca2+ concentrations observed during physiological stimulation (pCa 6.4), PLD was not stimulated, whereas incubation with guanosine 5'-O-(3-thiotriphosphate) at pCa 7.0 activated this enzyme. Aluminum fluoride (AlF4-) stimulated PLD, and this activity was insensitive to pertussis toxin after stimulation by either norepinephrine or AlF4-. These results indicate that PLD in vascular smooth muscle is activated by norepinephrine via stimulation of a pertussis toxin-insensitive G protein and not via an increase in intracellular Ca2+ levels.

Requirement of mammalian DNA polymerase-beta in base-excision repair

Synthesis of DNA by DNA polymerase-beta is distributive on single-stranded DNA templates, but short DNA gaps with a 5' PO4 in the gap are filled processively to completion. In vitro studies have suggested a role of beta-polymerase in different types of DNA repair. However, the significance of these studies to the in vivo role of beta-polymerase has remained unclear. Because genetic studies are essential for determining the physiological role of a gene, we established embryonic fibroblast cell lines homozygous for a deletion mutation in the gene encoding DNA polymerase-beta. Extracts from these cell lines were found to be defective in uracil-initiated base-excision repair. The beta-polymerase-deleted cells are normal in viability and growth characteristics, although they exhibit increased sensitivity to monofunctional DNA-alkylating agents, but not to other DNA-damaging agents. Both the deficiency in base-excision repair and hypersensitivity to DNA-alkylating agents are rescued following stable transfection with a wild-type beta-polymerase minitransgene. These studies demonstrate that beta-polymerase functions specifically in base-excision repair in vivo.

Utilizing OODB schema modeling for vocabulary management

Comprehension of complex controlled vocabularies is often difficult. We present a method, facilitated by an object-oriented database, for depicting such a vocabulary (the Medical Entities Dictionary (MED) from the Columbia-Presbyterian Medical Center) in a schematic way which uses a sparse inheritance network of area classes. The resulting Object Oriented Health Vocabulary repository (OOHVR) allows visualization of the 43,000 MED concepts as 90 area classes. This view has provided valuable information to those responsible with maintaining the MED. As a result, the MED organization has been improved and some previously-unrecognized errors and inconsistencies have been removed. We believe that this schematic approach allows improved comprehension of the gestalt of large controlled medical vocabulary.

Increase of the expression of midecamycin 4"-hydroxyl propionyltransferase gene (mpt) by a promoter-like fragment from the midecamycin producing strain

The promoter region of the midecamycin 4"-hydroxyl propionyltransferase gene (mpt) gene was reconstructed by PCR, and ligated with a fragment from the midecamycin producing strain (Streptomyces mycarofaciens var. 68) which contained fairly strong promoter activity (PLF). Recombinant plasmids pCHFPE2 (promoter region of mpt was reconstructed by combining the PLF in the upstream of its own promoter) and pCHFPE3 (the promoter of mpt was replaced by PLF) were obtained. The extent of expression of mpt was measured according to the amount of propionylspiramycin bioconverted from exogenous spiramycin by transformants of S. lividans TK24 containing pCHFPE2 and pCHFPE3. The results showed that the PLF could increase the expression of mpt in S. lividans TK24 up to 89.02% and 58.53%, respectively, and also enhance the expression in the industrial spiramycin producing strain S. spiramyceticus to a great extent.

Experimental study on the early efficacy of excimer laser with adjunctive balloon angioplasty in dog's femoral artery

The effect of domestically-manufactured excimer laser with adjunctive balloon angioplasty in achieving revascularization and reduction of residual stenosis was assessed. 20 femoral arteries with thrombosis and occlusion from 12 dogs were subject to angiography. At first excimer laser angioplasty was done followed by balloon angioplasty. The diameter and residual stenosis of revascularized vessel were measured. The result showed that 17 out of 20 vessels (85%) were revascularized. The diameter of revascularized vessel by excimer laser were 1.22 +/- 0.14 mm, while residual stenoses were 54% +/- 5%. After adjunctive balloon angioplasty the diameter and residual stenoses were 2.04 +/- 0.16 mm and 20% +/- 7% respectively (P < 0.05 and P < 0.01). Complication in form of vasoperforation occurred in 3/20 vessels (15%). It is concluded that China- manufactured excimer laser angioplasty is effective when used for revascularization. While the reduction of narrowing and residual stenoses was enhanced after adjunction of balloon angioplasty. This method can be employed in treating peripheral occlusive disease effectively and safely.

Towards more practical average bounds on supervised learning

In this paper, we describe a method which enables us to study the average generalization performance of learning directly via hypothesis testing inequalities. The resulting theory provides a unified viewpoint of average-case learning curves of concept learning and regression in realistic learning problems not necessarily within the Bayesian framework. The advantages of the theory are that it alleviates the practical pessimism frequently claimed for the results of the Vapnik-Chervonenkis (VC) theory and its alike, and provides general insights into generalization. Besides, the bounds on learning curves are directly related to the number of adjustable system weights. Although the theory is based on an approximation assumption, and cannot apply to the worst-case learning setting, the precondition of the assumption is mild, and the approximation itself is only a sufficient condition for the validity of the theory. We illustrate the results with numerical simulations, and apply the theory to examining the generalization ability of combination of neural networks.

[Structure analysis of a DNA fragment containing strong promoter activity from Streptomyces mycarofaciens 1748]

A HindIII-HindIII 2.0kb DNA fragment containing promoter activity has been cloned from medicamycin producing strain (S. mycarofaciens 1748), using promoter -probe plasmid vector pIJ486. Transformants of recombinant plasmid p4H2 containing this fragment were resistant to Km in the level above 500 micrograms/ml in MM medium. The result of subcloning deletion analysis indicated that different part of deletion of this fragment would show various extent of effect on the promoter activity. A rather complicated transcriptional regulatory mechanism was suggested. DNA sequence analysis revealed that this fragment consisted of 1984 nucleotides with 47.7% of G+C content. No typical ORF of Streptomyces gene was found. Certain regions showed some homologies with promoters of Streptomyces genes. In 520-570bp region, a sequence similar to the upstream activator sequence (UAS) of E.coli tRNA was discovered. This implied that a possible "enhancer" element was involved in Streptomyces gene transcription.

Dielectric study of the cooperative order-disorder transition in aqueous solutions of schizophyllan, a triple-helical polysaccharide

Schizophyllan exists in aqueous solution as a triple helix, which is intact at room temperature. Its aqueous solution forms some ordered structure at low temperatures but undergoes a sharp transition to a disordered structure as the temperature is raised. The transition temperature Tc is about 7 and 18 degrees C for H2O and D2O solutions, respectively. This transition was followed by time-domain reflectometry to investigate dynamic aspects of the transition. In addition to a major peak around 10 GHz, the dielectric dispersion curve of a 20 wt % schizophyllan in D2O exhibited a small peak around 100 MHz below Tc and around 10 MHz above Tc. The major peak is due to bulk water, whereas the 100 MHz peak is assigned to "bound" or "structured" water, and that around 10 MHz to side-chain glucose residues. However, unlike usual bound water reported for biopolymer solutions, this "structured" water disappears abruptly when the temperature becomes close to Tc without accompanying a conformational transition of the main chain. The above assignment is consistent with the structure of the ordered phase derived from previous static data that it consists of side-chain glucose residues along with nearby water molecules surrounding the helix core that are interacting with each other loosely through hydrogen bonds, and spreads radially only a layer of one or two water molecules but a long distance along the helix axis.

[Fetal fibronectin diagnosis of premature rupture of the amniotic membranes]

OBJECTIVE

To determine whether fetal fibronectin is a sensitive test for the detection of premature rupture of the amniotic membranes.

METHODS

Fetal fibronectin by ABC immunoblotting methods were measured in samples of cervicovaginal secretion from 80 cases with ruptured amniotic membranes (study group) and 50 cases of term pregnancy (control group A). Plasma fetal fibronectin were examined in 30 cases of normal pregnancy (control group B).

RESULTS

The detection rate of fetal fibronectin in the women with ruptured membranes was 95.0%, While 6% in normal pregnancy.

CONCLUSIONS

Fetal fibronectin is a sensitive test for detection of present of amniotic fluid. It can be used for diagnosis of ruptured amniotic membranes.

A phage display system for studying the sequence determinants of protein folding

We have developed a phage display system that provides a means to select variants of the IgG binding domain of peptostreptococcal protein L that fold from large combinatorial libraries. The premise underlying the selection scheme is that binding of protein L to IgG requires that the protein be properly folded. Using a combination of molecular biological and biophysical methods, we show that this assumption is valid. First, the phage selection procedure strongly selects against a point mutation in protein L that disrupts folding but is not in the IgG binding interface. Second, variants recovered from a library in which the first third of protein L was randomized are properly folded. The degree of sequence variation in the selected population is striking: the variants have as many as nine substitutions in the 14 residues that were mutagenized. The approach provides a selection for "foldedness" that is potentially applicable to any small binding protein.

Experimental study on the model of coronary artery thrombosis in dog

We have developed a model of coronary artery thrombosis in dog by using the method stimulating coronary adventitia with direct current. The results have shown that the thrombi are similar to human artery thrombi in composition and the model of coronary artery thrombosis is satisfactory and the time of forming thrombosis is shorter than that by other methods.

[Some biochemical indexes in white rabbit's blood affected by acute high intensity microwave]

Irradiation of white rabbits by 10, 50, 100 and 200 mW/cm2 microwave respectively can cause the disorder of protein metabolism, the abnormality of blood sugar, and the change of the activity of serum alpha-hydroxybutyrate dehydrogenase, lactate dehydrogenase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, acid phosphatase ect. These changes can be used as indexes in the evaluation of the effect of acute high intensity microwave exposure. The effect on the organism mainly depends on the intensity of exposure provided the dose of microwave remains the same.

[The effect of sodium prasterone sulfate on lactation]

To study the relationship between sodium prasterone sulfate and lactation, blood samples were collected from 120 cases. Sixty cases were in study group (at different periods: during the 3rd trimester, and 1st, 3rd day postpartum) including 30 cases using 100mg sodium prasterone sulfate, 30 cases (using 200mg sodium prasterone sulfate), 60 cases were in control group. The serum levels of estradiol (E2), prolactin (PRL) and plasma levels of oxytocin (OT) were measured by radioimmunoassay, and the production of breast milk was observed. The results showed no statistically significant difference of serum E2, PRL and plasma OT between (sodium prasterone sulfate) study groups and control groups, and the production of breast milk indicated also no significant difference between the 2 groups. The conclusion is that low-dose sodium prasterone sulfate (200mg/day, 600mg/week) did not affect the production of breast milk.

Transcriptional repression of fibronectin gene expression in v-src transformation

V-src-dependent and -independent alterations in the steady-state content, rates of synthesis, and turnover of fibronectin protein and mRNA were identified using rat fibroblasts which are temperature sensitive for p60v-src activity. Activation of p60v-src caused a fivefold reduction in the rate of fibronectin biosynthesis. The v-src-dependent decrease in fibronectin biosynthesis resulted from a similar reduction in the steady-state content of fibronectin mRNA. This change was reversible and required more than 24 h, implying an indirect effect of p60v-src on fibronectin gene expression. The rate of fibronectin mRNA turnover and pattern of alternative splicing were unchanged following p60v-src activation, indicating that these regulatory steps are insensitive to v-src transformation. A v-src-specific reduction of at least threefold was measured for the rate of fibronectin gene transcription, and gene transfer studies using fibronectin promoter-CAT reporter genes indicated that transcriptional repression occurs at the level of initiation. When p60v-src was inactive, CAT reporter genes controlled by 4.9 or 3.2 kb of the rat fibronectin promoter exhibited relatively increased CAT activity (approximately twofold) compared to another CAT reporter construction controlled by only 880 bp of the fibronectin promoter. In contrast, CAT activity was relatively reduced (approximately twofold) for the reporter constructions containing 4.9 or 3.2 kb of the promoter when p60v-src was active. These findings indicate that the distal portion of the fibronectin promoter contains a v-src-sensitive element(s) which mediates a decrease in the rate of fibronectin transcription initiation by negative control.

Biogenic amine flux mediated by cloned transporters stably expressed in cultured cell lines: amphetamine specificity for inhibition and efflux

LLC-PK1 cells have been stably transfected with cDNAs encoding the human norepinephrine transporter (NET), rat dopamine transporter (DAT), and rat serotonin transporter. Using these cell lines, the specificity of each transporter toward agents that inhibit substrate influx and stimulate substrate efflux across the plasma membrane was examined. With 1-methyl-4-phenylpyridinium as a substrate for DAT and NET and serotonin as a substrate for the serotonin transporter, each transporter demonstrated a distinct pattern of inhibition by a panel of amphetamine derivatives and analogs, including amphetamine, methamphetamine (also known as "ecstasy"), p-chloroamphetamine, 3,4-methylenedioxymethamphetamine, methylphenidate (ritalin), and 5-methoxy-6-methyl-2-aminoindan. For each cell line expressing a single biogenic amine transporter, efflux of the accumulated substrate was stimulated by amphetamine derivatives, and this efflux was blocked by mazindol, an inhibitor of all three transporters. Of the amphetamine derivatives tested, some caused efflux at concentrations similar to those that inhibited transport. Other derivatives were much less effective at stimulating efflux than at inhibiting uptake. Methylphenidate caused little or no efflux, although it blocked uptake mediated by both NET and DAT. Other inhibitors of transport, such as cocaine, mazindol, citalopram, and nisoxetine, failed to stimulate efflux from these cells at concentrations that inhibited influx. The results suggest that potency toward individual plasma membrane biogenic amine transporters and the ability to release accumulated amine substrates are independent properties of each amphetamine derivative.

Population-Growth Potential of Epiphyas-Postvittana, the Lightbrown Apple Moth (Lepidoptera, Tortricidae) in Relation to Diet, Temperature and Climate

Life-history parameters and developmental rates of Epiphyas postvittana were determined for four natural food plants and Shorey's diet at each of six temperatures. The rate of development of larvae and the life-history parameters were influenced by both temperature and diet. The highest r(m) value was given by populations feeding on Plantago lanceolata, followed by those on Shorey's diet and Rumex crispus, all at 25 . 2 degrees C, then by Malus pumila at 19 . 9 degrees C and Trifolium repense at 25 . 2 degrees C. Zero population growth occurred at 7 . 1 and 30 . 7 degrees C. A life-table study of five geographical strains of the moth under non-variable conditions (constant temperature and artificial diet) showed that finite rate of increase (lambda) was significantly correlated with climatic features of habitats, viz. mean annual Values of temperature, rainfall and relative humidity. Peak values of lambda occurred at cooler temperatures, moderate levels of habitat moisture and high altitudes (500-1000 m); the Canberra population gave the highest value (lambda = 1 . 157), followed by Armidale (lambda = 1 . 152), Melbourne (lambda = 1 . 141), Mildura (lambda = 1 . 135) and Auckland (lambda = 1 . 118). Higher performance of E. postvittana on herbaceous plants than on woody plants suggests that it primarily evolved as a feeder on herbaceous plants.

[Insulin resistance and pregnancy induced hypertension]

Plasma glucose and serum insulin in oral glucose tolerance test (OGTT) were measured in 40 patients with pregnancy induced hypertension (PIH) and 30 normal pregnancies. Compared with the controls, serum insulin concentration, plasma glucose and their area under the curve (AUC) increased in 15 patient with severe PIH, in 0.5, 1, 2, 3 hours postload (P < 0.05) of OGTT. The relationship between diastolic blood pressure and integrated area under the curve for serum insulin concentration (r = 0.35, P < 0.05) were observed in 15 patients with severe PIH. The results indicated that patients with severe PIH are insulin resistant and hyperinsulinemic after an oral glucose load.

Cre-loxP-mediated gene replacement: a mouse strain producing humanized antibodies

BACKGROUND

The bacteriophage-derived Cre-loxP recombination system operates efficiently in mammalian cells. This system is particularly useful in gene-targeting experiments in the mouse, and has already been used to generate 'clean' deletions of target genes in the germ line, as well as to inactivate target genes in a conditional manner (based on regulated expression of the Cre recombinase). In principle, Cre-loxP-mediated recombination should also allow gene replacement, and thus the introduction of virtually any kind of mutation into the genome.

RESULTS

We used the Cre-loxP system, in mouse embryonic stem cells, to replace the mouse gene C gamma 1, which encodes the constant region of the heavy chain of IgG1 antibodies, with its human counterpart. The mutation was transmitted through the mouse germ line, and the resulting mutant mice were crossed with mice expressing kappa light chains with a human, instead of a mouse, constant region. Mice homozygous for both mutations produce humanized, kappa-chain-bearing IgG1 antibodies at the same level and efficiency as wild-type mice produce murine IgG1 antibodies. These animals should enable the ex vivo production of humanized, chimeric monoclonal antibodies specific for any antigen to which the mouse can respond.

CONCLUSIONS

Cre-loxP-mediated gene replacement is a simple and efficient general method of targeted mutagenesis in the mouse.

Deletion of a DNA polymerase beta gene segment in T cells using cell type-specific gene targeting

Deletion of the promoter and the first exon of the DNA polymerase beta gene (pol beta) in the mouse germ line results in a lethal phenotype. With the use of the bacteriophage-derived, site-specific recombinase Cre in a transgenic approach, the same mutation can be selectively introduced into a particular cellular compartment-in this case, T cells. The impact of the mutation on those cells can then be analyzed because the mutant animals are viable.

Comparison of the effects of antimitotic drugs on alpha-tubulin mRNA, microtubules and nicotinic receptor-mediated catecholamine secretion in adrenal chromaffin cells in culture

1. Four hour treatments of adrenal chromaffin cells with colchicine (10, 100 microM and 1 mM), tubulozole (10 microM) or podophyllotoxin (100 microM) decreases alpha-tubulin mRNA content. Vinblastine (10 microM) and taxol (10 microM), however, do not decrease alpha-tubulin mRNA content. 2. Immunocytochemical techniques demonstrate that 4 hr treatments with all of the antimitotic drugs (colchicine, podophyllotoxin, taxol, tubulozole and vinblastine) produce abnormal microtubule arrays. 3. The effects of 4 hr treatments with the antimitotic drugs on adrenal catecholamine secretion are all qualitatively the same; each drug selectively inhibits adrenal nicotinic acetylcholine receptor-stimulated catecholamine release, while having no inhibitory actions on release stimulated through noncholinergic mechanisms. 4. These studies demonstrate that autoregulation of tubulin synthesis occurs in cultured adrenal chromaffin cells. 5. All of the antimitotic drugs selectively inhibit nicotinic receptor-mediated adrenal catecholamine release under treatment conditions that affect adrenal microtubules. These results support the possibility that the actions of the antimitotic drugs on adrenal nicotinic receptors may involve microtubules.

[Changes in blood oxytocin levels in cases of pregnancy induced hypertension]

Serial measurements of plasma oxytocin concentration were done by radioimmunoassay in 38 cases of pregnancy induced hypertension (PIH) and 38 cases of normal pregnancy (NP). The results showed that there was no obvious difference in the plasma oxytocin concentration between patients with early PIH and NP, but a higher concentration in cases with PIH at term pregnancy than that in NP and a significantly higher level in intrapartum women with PIH. The results also indicated a much higher oxytocin concentration in cases of moderate and severe PIH as compared to that of NP. An obviously higher level of plasma oxytocin was found in severe PIH than in mild PIH. Based on this study we suggest that the clinical use of oxytocin in cases with PIH should be different from that in NP.

Human norepinephrine transporter. Biosynthetic studies using a site-directed polyclonal antibody

Antibodies have been raised against synthetic peptides derived from the predicted primary sequence of the human cocaine- and antidepressant-sensitive norepinephrine (NE) transporter (NET). One antibody (N430), raised and purified against a putative intracellular human norepinephrine transporter (hNET) epitope, detects hNET expression in a stably transfected cell line (LLC-NET) by indirect immunofluorescence only in the presence of detergent, while no immunoreactivity is observed in either the parental cells (LLC-PK1) or in LLC-NET cells incubated with preimmune sera or peptide absorbed antibody. N430 immunoblots of LLC-NET cell extracts reveal two major immunoreactive hNET species in these cells, migrating at 80 and 54 kDa, respectively. Pulse-chase N430 immunoprecipitation studies confirm that the 54-kDa species is a transient, glycosylated intermediate of a longer lived, more highly glycosylated protein with an apparent M(r) of 80,000. In contrast, a 54-kDa species is the primary hNET product in vaccinia virus T7-infected HeLa cells, transiently transfected with hNET cDNA. PNGase F digestion of extracts prepared from LLC-NET- and hNET-transfected HeLa cells convert all immunoreactive species to a 46-kDa form, equivalent to that observed following incubation of whole cells with the glycosylation inhibitor tunicamycin. As transiently transfected HeLa and stable LLC-NET cells exhibit a pharmacologically similar NE transport activity, it appears likely that the additional glycosylation evident in the stable line does not contribute significantly to antagonist sensitivity. On the other hand, NE transport and antagonist ([125I]RTI-55) binding assays on whole LLC-NET cells treated with tunicamycin reveal a pronounced reduction in NE transport activity and hNET membrane density paralleled by an inability of NET proteins to replenish the higher M(r) hNET pool. These findings suggest an obligate role for N-linked glycosylation in hNET biosynthetic maturation, stability, and functional expression. In summary, N430 antibody is a useful tool for the visualization and characterization of hNET gene products and has permitted the first direct evaluation of biosynthetic steps leading to functional catecholamine transporter expression.

Gene targeting and its application to the study of B-cell development

The use of gene targeting technology for the study of gene functions in vivo continues to expand. The application of this technology as well as further improvements in the technology itself enable us to examine the influence of various genetic elements and gene products on B-lymphocyte development and function.

Stable expression of biogenic amine transporters reveals differences in inhibitor sensitivity, kinetics, and ion dependence

We have constructed stable cell lines expressing transporters for dopamine (DA), norepinephrine (NE), and serotonin (5-HT) by transfection with cloned cDNAs. The parental LLC-PK1 cell does not express any of these neurotransmitter transporters. Therefore, monoamine transport activities in each of these cell lines are due to the transfected DNA only, allowing comparison in the same background. Drug inhibition profiles for each cell line are distinct and as expected for each transporter. LLC-NET and LLC-DAT cells transported both NE and DA and both cell types exhibited a lower KM for DA transport than for NE transport. Analysis of Vmax data for LLC-NET cells suggests that substrate is bound to the NE transporter during the rate-limiting step(s) in transport. The cocaine analog 2-beta-carbomethoxy-3 beta-(4-[125I]iodophenyl)tropane binds to each cell type, and is displaced by transport substrate in each case. Binding and transport measurements on parallel cell cultures allowed estimation of turnover numbers for norepinephrine, dopamine, and serotonin transporters. All three transporters require external Na+ and Cl-. The Na+ concentration dependence suggests that a single Na+ ion is involved in transport catalyzed by norepinephrine and serotonin transporters while more than one Na+ ion participate in transport mediated by the dopamine transporter.

Generation of a mouse strain that produces immunoglobulin kappa chains with human constant regions

Humanized antibodies are highly efficient as immunotherapeutic reagents and have many advantages over rodent antibodies. A mouse strain was generated by gene targeting to replace the mouse kappa light chain constant (C) region gene with the human C kappa gene. Mice homozygous for the replacement mutation (C kappa R) produced normal concentrations of serum antibodies, most of which carry chimeric kappa light chains, and mounted normal immune responses to hapten-protein conjugates. This technology provides a feasible option for the generation of high-affinity humanized antibodies by means of the powerful somatic hypermutation-selection mechanism.

(+)Naloxone potentiates the inotropic effect of epinephrine in the isolated dog heart

Naloxone potentiates the inotropic effect of circulating catecholamines in the isolated canine heart. The stereospecificity of this response was evaluated with the aid of the less active (+)enantiomer of naloxone. The more common (-)isomer of naloxone increased the contractile response to epinephrine only at the higher dose tested (4 mg). This effect of naloxone was not observed at a tenfold lower dose (0.4 mg), indicating a very narrow dose-response range. (+)Naloxone was effective at the lower dose and was, therefore, equal to or better than (-)naloxone in potentiating the inotropic effect of epinephrine. When introduced afterward, (-)naloxone did not add to the effect of (+)naloxone. These data suggest that naloxone modifies cellular responsiveness to catecholamines through a nontraditional opiate receptor, through a nonopiate receptor, or through a nonreceptor mechanism.

Independent control of immunoglobulin switch recombination at individual switch regions evidenced through Cre-loxP-mediated gene targeting

We have employed a method based on the Cre-loxP recombination system of bacteriophage P1 to generate a mouse strain in which the JH segments and the intron enhancer in the IgH locus are deleted. By analysis of immunoglobulin isotype switch recombination in heterozygous mutant B cells activated by lipopolysaccharide plus interleukin-4, we show that, on the mutant chromosome, switch recombination at the mu gene switch region is strongly suppressed, whereas the switch region of the gamma 1 gene is efficiently rearranged. These data demonstrate an independent control of switch recombination at individual switch regions and suggest that, in the process of switch recombination, the alignment of the recombining strands occurs independently of and probably after the introduction of double-strand breaks into the switch regions involved.

Mechanisms of oxygen-induced contraction of ductus arteriosus isolated from the fetal rabbit

The present study was designed to investigate the effect of O2 on intracellular Ca concentration ([Ca]i) in the ductus arteriosus and the mechanisms for O2-induced ductal contraction. The force of isometric contraction of the ring of the ductus arteriosus isolated from fetal rabbits at 30 days of gestation (term, 31 days) was measured. The ductus arteriosus was loaded with fura 2, a calcium-sensitive dye, and [Ca]i was determined from the ratio of fluorescence intensity at 340 and 380 nm excitation wavelengths. The ductus arteriosus was initially superfused with hypoxic control solutions and contraction was induced by application of oxygenated solutions. The O2-induced contraction of the ductus arteriosus was associated with increases in [Ca]i and was eliminated in the absence of extracellular calcium. An increase in [K]o from 5 to 50 mM, which causes membrane depolarization, induced ductal contraction. The calcium channel blockers verapamil, diltiazem, and nickel caused a similar inhibition of O2-induced contraction as well as KCl-induced contraction. The role of intracellular calcium stores in O2-induced ductal contraction was examined using ryanodine, an inhibitor of calcium uptake and release from the sarcoplasmic reticulum. The inhibition of O2-induced contraction by ryanodine was minimal. Infusion of glibenclamide, an inhibitor for opening the ATP-sensitive potassium channel, caused contraction of the ductus arteriosus in the hypoxic solution. Cromakalim, an opener of ATP-sensitive potassium channels, completely relaxed the contraction induced by O2. These data suggest that O2 increases [Ca]i and causes contraction in the ductus arteriosus. Application of O2 may change from anaerobic to aerobic metabolism and depolarize membrane potential by closing the ATP-sensitive potassium channel, which in turn increases calcium influx via the voltage-dependent calcium channel. Mechanisms other than the ATP-sensitive potassium channel may also be involved in the O2-induced contraction and remain to be studied.

Anti-inflammatory oleanane triterpenes from Tripterygium wilfordii cell suspension cultures by fungal elicitation

Treatment of cell suspension cultures of Tripterygium wilfordii with an autoclaved Botrytis sp. homogenate rapidly increased the synthesis of a family of oleanane and friedelane triterpenes, including the antiinflammatory oleanane triterpene 3β,22α-dihydroxyolean-12-en-29-oic acid. This compound exceeded 30 mg · l(-1) in 13 day elicitations with 12 l bioreactors, in contrast to control levels of less than 5 mg · l(-1). Cell cultures treated with the fungal elicitor provided higher triterpene yields in less time than cultures in a diterpene production medium or whole plants. Elicited production has been developed for commercial application in light of the successful treatment of rheumatoid arthritis with Tripterygium extracts.

Immunoglobulin heavy and light chain genes rearrange independently at early stages of B cell development

The compartment of mouse B cell progenitors can be resolved into five developmentally related fractions by multicolor flow cytometry. Using this system and employing mutant mice in which the membrane exon of the mu chain, the lambda 5 gene, or the JH locus was inactivated by gene targeting, we found that expression of the pre-B cell receptor complex is necessary for the transition from the large CD43+ to the small CD43- pre-B cell stage. We report the occurrence of immunoglobulin heavy and light chain gene rearrangement at the stage of large B cell precursors. We show that neither the pre-B cell receptor complex nor any gene rearrangement in the heavy chain locus is required for the induction of kappa light chain gene rearrangement in early B cell progenitors.

HCO3(-)-dependent intracellular pH regulation in the premature myocardium

This study investigated developmental changes in Na(+)-H+ exchange and HCO3(-)-Cl- exchange activities in newborn and adult rabbit hearts. pHi was measured using the fluorescent dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein in isolated myocytes. Myocardial mechanical function was measured in the isolated ventricular preparation. Intracellular acidosis with normal pHo was induced by an NH4Cl (10 mM) prepulse technique. Upon removal of NH4Cl, pHi fell transiently and then recovered toward the control level. In the HCO3-/CO2-buffered solution, the rate of recovery of pHi in the newborn was greater than in the adult. In the HCO3-/CO2-buffered solution, 5-(N-ethyl-N-isopropyl)amiloride (EIPA), an inhibitor of Na(+)-H+ exchange, inhibited the recovery of pHi completely in the adult. In the newborn, however, significant recovery of pHi was observed in the presence of EIPA. In the presence of both EIPA and 4-acetamido-4'-isothiocyanatostilbene-2',2'-disulfonic acid (SITS), an inhibitor of HCO3(-)-Cl- exchange, the recovery of pHi was not observed in the two age groups. In the HEPES-buffered solution that did not contain HCO3-/CO2, the rate of recovery of pHi after NH4Cl removal was similar in the two age groups. In the HEPES-buffered solution, the recovery of pHi was completely inhibited by EIPA in the two age groups. In the presence of EIPA in the HCO3-/CO2-buffered solution, contractile function decreased during acidosis after NH4Cl removal and did not recover in the adult. In the newborn, significant recovery of contractile function was observed after NH4Cl removal in the presence of EIPA. The recovery of mechanical function observed in the presence of EIPA in the newborn was inhibited by SITS. These data suggest that, although there is no developmental change in the Na(+)-H+ exchange activity, HCO3(-)-Cl- exchange is more active in the premature myocardium. The presence of the HCO3(-)-Cl- exchanger is important in maintaining myocardial contractile function during acidosis, especially when Na(+)-H+ exchange is inhibited and may partly explain the greater resistance of the premature myocardium to acidosis.

Norepinephrine stimulates the direct breakdown of phosphatidyl inositol in rat tail artery

When segments of rat tail artery were labeled with [3H]inositol and then stimulated with norepinephrine (NE), the inositol phosphates produced were primarily IP and IP2, together with a small but significant amount of Ins(1,4,5)P3 and a very small amount of Ins(1,3,4,5)P4. It has been unclear in many studies whether or not the relatively large levels of IP and IP2 produced in [3H]inositol-labeled tissue represent indirect products of phosphatidyl inositol(4,5)bis phosphate breakdown (through Ins(1,4,5)P3) or direct products of phosphatidyl inositol 4 monophosphate and phosphatidyl inositol breakdown. In order to answer this question tail artery segments were prelabeled with [3H]inositol and then permeabilized with beta escin and stimulated with norepinephrine and GTP gamma S, so that increases in IP, IP2, and Ins(1,4,5)P3 were still observed. If these permeable segments were stimulated with agonist in the presence of compounds known to inhibit Ins(1,4,5)P3 5-phosphatase, such as glucose 6P, (2,3)diphosphoglycerate, or Ins(1,4,5)P3, the levels of labeled Ins(1,4,5)P3 and labeled IP2 were increased, while the level of stimulated labeled IP was unchanged. This indicated that some of the IP2 and IP formed in these cells was produced from PIP2 but that some of these compounds might be formed from PIP or PI. When the isomers of inositol monophosphate, Ins 1P and Ins 4P, were separated by HPLC, it was shown that after prelabeled tail artery was stimulated by norepinephrine for periods of 1-2 min, the predominant isomer formed was Ins 4P, indicating either PIP2 or PIP as the source. However, after 5-20 min stimulation, both Ins 1P and Ins 4P were formed in equal amounts, suggesting that during sustained stimulation of smooth muscle PI itself was broken down directly. Therefore it appears that within 1-2 min of norepinephrine addition to vascular smooth muscle the bulk of the IP and IP2 produced are derived from PIP2 via IP3, while after 20 min of norepinephrine treatment much of the IP comes directly from PI. This suggests that the regulation of PLC in this tissue is more complicated than has been previously believed.

Dynorphin, naloxone, and overflow of norepinephrine during cardiac nerve stimulation in dogs

The effects of dynorphin-(1-9) and naloxone on norepinephrine (NE) overflow and myocardial contractility were determined during left cardiac nerve stimulation in the anesthetized dog. Stimulation-induced increases in NE overflow from the left ventricle were monitored during control conditions, during infusion of dynorphin-(1-9), during dynorphin plus naloxone, and after naloxone alone. Four electrical stimulations were applied for 1 min at 20-min intervals. Repeated left cardiac nerve stimulations (control group) reduced stimulated NE overflow 50-60% by 1 h. If stimulations were only conducted at 0 and 1 h, the decline in NE overflow was not observed. Intracoronary dynorphin (2 nmol.min-1.kg-1, 20 min) lowered the stimulation-induced increase in NE overflow further and reduced first time derivative of left ventricular pressure (dP/dt) and myocardial O2 consumption responses. Naloxone (100 micrograms/kg) prevented all of the dynorphin-mediated effects. When given alone, naloxone increased both NE overflow and left ventricular dP/dt during stimulation and prevented or significantly delayed the gradual decline in overflow observed in stimulated controls. A postjunctional effect of dynorphin was evaluated by comparing contractile responses to the intracoronary infusion of NE before and during dynorphin. Dynorphin did not alter contractile function at rest or during NE infusion. In summary, dynorphin-(1-9) depresses nerve stimulation-induced, cardiac NE overflow, and myocardial contractility in a naloxone-reversible fashion. Alone, naloxone appears to regulate stimulated NE overflow through a qualitatively different mechanism. Endogenous opioids may normally moderate myocardial function during cardiac nerve stimulation by regulating junctional NE concentrations through a combination of effects on NE release and/or its subsequent reuptake.

Norepinephrine-induced phosphatidylcholine hydrolysis by phospholipases D and C in rat tail artery

Rat tail arterial segments were incubated with [3H]choline to selectively label endogenous phosphatidylcholine. Norepinephrine (NE; 10(-5) M) addition for periods of 10 s to 30 min significantly increased the concentration of extracellular phosphatidylcholine metabolites, [3H]choline, and [3H]phosphocholine. The release of [3H]choline and [3H]phosphocholine from the segments was NE dose dependent (10(-6)-10(-3) M). NE also increased the formation of [3H]phosphatidylethanol in [3H]myristate-labeled tail artery in the presence of ethanol, characteristic of phospholipase D activity. NE-induced phosphatidylcholine hydrolysis was blocked by pretreatment with prazosin (10(-5) M) and was unchanged by pretreatment with propranolol (10(-5) M). 4 beta-phorbol 12,13-dibutyrate (PDBu, 10(-6) M) stimulated the release of [3H]choline, which was inhibited by pretreatment with staurosporine (10(-5) M). The stimulatory effect of NE on phosphatidylcholine metabolism was not altered by either pretreatment with staurosporine (10(-5) M) or calcium-free buffer. In summary, we have demonstrated NE-stimulated phosphatidylcholine hydrolysis by phospholipase D and C in intact vascular smooth muscle. This effect of NE was dose dependent and was mediated through the alpha 1-adrenergic receptor. Norepinephrine and PDBu stimulated phosphatidylcholine hydrolysis through different mechanism(s), and the stimulatory effect of NE did not seem to require protein kinase C and calcium influx.