Involvement of antioxidant enzymes in multiple-drug resistance in a human T-lymphoblastic leukemia-cell line which over-expresses p-glycoprotein

We have compared the specific activities of Cu/Zn superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in a vinblastine sensitive human T-lymphoblastic cell line (CCRF-CEM) and its multiple drug resistant (MDR) counterpart cell line (CEM/VLB100), which over-expresses P-glycoprotein (PGP). We have found that the specific activity Cu/Zn SOD was consistently 38% increased in CEM/VLB100 cells compared with CCRF-CEM cells. In contrast, the activities of CAT and GSH-Px were similar in the two cell lines. These results suggest that MDR in CEM/VLB100 is a complicated phenotype which not only involves a PGP mechanism, but also a SOD protection mechanism against drug-mediated O2.- cytotoxicity.

Expression of IGF-II/Man-6-P receptors on rat, rabbit, and human colon epithelial cells

Previous experiments from this laboratory have established the presence of receptors for insulin and insulin-like growth factor I (IGF-I) on apical membranes prepared from rabbit colon epithelial cells; however, no receptors for multiplication-stimulating activity (MSA), the rat peptide hormone equivalent of human IGF-II, were found in this tissue. In the current studies, radioligand binding assays, covalent cross-linking experiments, and immunoblot analyses using a polyclonal rabbit antiserum that recognizes the IGF-II/mannose 6-phosphate (Man-6-P) receptor, all confirmed the presence of IGF-II/Man-6-P receptors on membranes prepared from rat and human colon epithelial cells. Exposure of rat colon epithelial cell membrane fractions to 5 mM Man-6-P before incubation with 125I-labeled IGF-II increased radioligand binding. Immunoblot analysis indicated that IGF-II/Man-6-P receptors were present in both unfractionated rat colon membranes and fractions enriched with apical membranes. Rabbit and human colon epithelial cells displayed a different pattern of receptor distribution than rat colon epithelial cells, with more insulin receptors but relatively few IGF-II/Man-6-P receptors. Immunohistochemical studies using a rabbit polyclonal antiserum confirmed that IGF-II/Man-6-P receptors were present on both the apical and the basolateral surfaces of colon epithelial cells.

Effect of sulfhydryl reagents on spectrin states on the erythrocyte membrane

The unique properties of erythrocytes are largely determined by its fibrillar network under the plasma membrane. Spectrin, one major component of the membrane skeleton, has been suggested to play a central role in this process. To understand the mechanism underlying this process, the effect of the sulfhydryl groups of erythrocyte membrane on spectrin structure and function was studied. By using non-denaturing gel analysis, dithiothreitol was found to protect spectrin in its tetramer state. In contrast, iodoacetamide and N-ethylmaleimide enhanced conversion of the spectrin tetramer to dimer and decreased its binding to the membrane. Moreover, when the membrane was treated with cadmium, the tetramer was converted to the dimer on the membrane, while zinc had no effect. Hemolysis experiments showed that cadmium could lyse erythrocytes in vitro. These results indicated that preservation of the spectrin tetramer or even higher oligomer states, by the sulfhydryl groups may be important to the membrane integrity and the intact cell functions.

Effects of intermediate metabolites of 37 xenobiotics on the catalytic activities of reconstituted cytochrome P-450IIB1 and P-450IA1 enzyme systems

Direct effects of intermediate metabolites of 37 different xenobiotics on the catalytic activities of both reconstituted cytochrome P-450IIB1 and P-450IA1 enzyme systems were studied by determination of NADPH oxidation at various intervals after initiation of the reaction. The results showed that cytochrome P-450IIB1 isozyme was much more likely than cytochrome P-450IA1 isozyme to be attacked by the reactive intermediates formed by some xenobiotics with smaller molecular weight and lose its catalytic activities. These xenobiotics were carbon tetrachloride, chloroform, carbon disulfide, benzene, parathion, methylparathion, methyldursban and dimethylnitrosamine. In contrast, however, steadily increasing metabolic activities were observed towards benzo(a)pyrene, 3-methylcholanthrene and polychlorinated biphenyls in reconstituted cytochrome P-450IA1 enzyme system as the reaction time prolonged within 4 min. The method discussed in this paper could be used as a simple and convenient way to observe directly the autocatalytic destruction of P-450 enzymes by some chemical agents.

High field proton NMR investigations of the metabolic profiles of multidrug-sensitive and -resistant leukaemic cell lines: evidence for diminished taurine levels in multidrug-resistant cells

High field proton (1H) nuclear magnetic resonance (NMR) spectroscopy has for the first time been employed to investigate and compare the metabolic profiles of vinblastine-sensitive and -resistant T-lymphoid leukaemic cell lines (CCRF-CEM and CEM/VLB100 respectively) and evidence is presented for a significantly lower taurine content in the CEM/VLB100 resistant subline when expressed relative to that of its drug-sensitive parental counterpart. These data suggest differences in the nature and relative involvements of taurine biosynthetic pathways between the two cell lines, a phenomenon that may be related to their differing sensitivities towards chemotherapeutic agents such as adriamycin which promote the generation of cytotoxic reactive oxygen species (ROS) in vivo. However, the 1H NMR data obtained provided no evidence for an increased metabolic consumption of hypotaurine (a metabolic precursor of taurine with powerful .OH radical scavenging properties) in CCRF-CEM cells since differences observed in the hypotaurine: taurine concentration ratio between the drug-sensitive and -resistant cell lines were not statistically significant. Furthermore, hypotaurine is unlikely to compete with alternative endogenous .OH radical scavengers present such as lactate since its level in either of the two cell lines investigated (ca. 6.0 x 10(-8) mol./10(8) cells) is insufficient for it to act as an antioxidant in this context. The biochemical and therapeutic significance of these results are discussed.

A mutation generating a stop codon in the alpha-L-fucosidase gene of a fucosidosis patient

Fucosidosis is an autosomal recessive, lysosomal storage disease featured by deficient activity of alpha-L-fucosidase. Lymphoid cell lines from a fucosidosis patient (JT) and a healthy individual (control) contained alpha-L-fucosidase mRNA of the same size, 2.3 Kb, as determined by Northern blot analysis. cDNA was prepared from alpha-L-fucosidase mRNA of JT and control cells and each cDNA was amplified by the polymerase chain reaction. Direct DNA sequencing of the amplified products revealed a single mutation in JT, a G1141-->T transition. This changed the codon (GAA) for Glu-375 to a stop codon (UAA). Amplification and sequencing of the area containing the G1141-->T transition in genomic DNA of JT and control cells demonstrated that the mutation was homozygous in JT. Analysis of cDNA and genomic DNA derived from lymphoid cells of mother JT revealed her to be heterozygous (G and T) at position 1141. The G1141-->T mutation is probably responsible for disease in JT.

Identification of a genetically distinct subspecies of Mycobacterium kansasii

To assess the usefulness of a specific DNA probe for Mycobacterium kansasii, 105 isolates from Australia, Belgium, Japan, South Africa, and Switzerland were collected and analyzed. Twenty of these isolates were probe negative, of which 18 were from Belgium and Switzerland. Analysis of all isolates by Southern blot hybridization indicated a lack of variability among probe-positive isolates, while probe-negative isolates were clearly distinct and showed greater diversity. Sequence analysis of the 250 nucleotides at the 5' end of the 16S rRNA gene revealed that 19 of the 20 probe-negative isolates had a sequence different from that of M. kansasii. A total of five nucleotide differences were present in a cluster consisting of two nucleotide deletions and three nucleotide substitutions. These results suggest the existence of a genetic subspecies of M. kansasii.

[Cytological observation on culture of embryo in vitro of Tripterygium hypoglaucum (level.) Hutch]

This paper for the first time reports the embryo culture in vitro of Tripterygium hypoglaucum. Callus, adventitious roots and adventitious protuberances were induced from the cultured embryos in vitro. Multi-buds at the excised embryo tip were also observed at the same time. Cytohistological examination showed (1) callus was histologically easy to be induced to form adventitious roots; (2) callus on the cotyledons was originated from the epidemical and subepidemical cells of the cotyledons, and the adventitious roots were originated from the disperse meristematic tissue or vascular tissue in the callus obtained from cultured excised embryos.

Identification of the promoter region of the Escherichia coli major cold shock gene, cspA

The major cold shock protein of Escherichia coli, CS7.4, is produced at a level of 13% of total protein synthesis upon a temperature shift from 37 to 10 degrees C. The transcription of its gene (cspA) was found to be tightly regulated and induced only at low temperature. In addition, the cspA mRNA was extremely unstable at 37 degrees C, so that CS7.4 production was hardly detected when the culture temperature was shifted from 15 degrees C to 37 degrees C. The transcription initiation site (+1) was identified. In vivo footprinting demonstrated that the region from bases -35 to -73 was protected from chemical modification, and gel mobility shift analysis showed that a cold-shocked cell extract contained a factor(s) specifically bound to the fragment containing the sequence between bases -63 and -92. This factor was synthesized de novo only at low temperature, and its synthesis was inhibited by chloramphenicol. Possible functions of this factor are discussed.

Localization and retention in vitro of fluorescently labeled aortic baroreceptor terminals on neurons from the nucleus tractus solitarius

The anterograde fluorescent tracer DiA was used to visualize baroreceptor fibers and synaptic terminals both in living and fixed tissue. Baroreceptor fibers labeled with DiA terminated as a dense synaptic field in the medial nucleus tractus solitarius (NTS), making synaptic contact on the soma, as well as processes of neurons that they innervated. A similar distribution and morphology was observed in baroreceptor fibers and terminals labeled with horseradish peroxidase. DiA also identified baroreceptor terminals and the neurons receiving these synaptic contacts in vitro. NTS neurons were dissociated from their surrounding tissue and identified by attached baroreceptor terminals that retained the fluorescent dye. These results will enable us to study the electrophysiological properties of dispersed neurons that receive identified baroreceptor synaptic terminals.

Gadolinium and mechanotransduction of rat aortic baroreceptors

The cellular mechanisms enabling baroreceptors to transduce wall distortion into axonal discharge are unknown but might involve stretch-activated ion channels. Gadolinium (Gd3+, 10 microM) blocks stretch-activated channels in several preparations. Here we tested Gd3+ effects on discharge responses of 15 single-fiber baroreceptors in vitro. We simultaneously measured discharge, pressure, and aortic diameter at Gd3+ concentrations from 0.001 to 400 microM. High levels of Gd3+ added to a bicarbonate-buffered perfusate (Krebs) slightly shifted the pressure-discharge relation (less than 4 mmHg, n = 3, P = 0.01) without affecting slope or discharge frequency at threshold. Gd3+ in Krebs variably altered the pressure-diameter relation. Because 500 microM Gd3+ produced visible precipitate in Krebs, we tested Gd3+ in a simpler perfusate using N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES). Gd3+ in HEPES (n = 10) induced minor, but statistically significant, average increases in threshold (less than +5-7%) and no changes in gain. However, prolonged HEPES exposure alone (n = 2) produced similar shifts. Electron microscopy verified that Gd3+ diffused from the lumen to reach extracellular locations near baroreceptor endings. We conclude that 1) HEPES perfusate alone reversibly depresses baroreceptor discharge and 2) Gd3+ has no direct effects on baroreceptors. Thus it appears that aortic baroreceptor mechanotransduction must utilize a different class of stretch-activated ion channels.

The accuracy of catheter-tip pressure transducers for the measurement of intrauterine pressure in labour

OBJECTIVE

To assess the reliability of intrauterine pressure measurements in labour with transducer tipped catheters.

DESIGN

Prospective clinical study.

SETTING

Delivery ward, National University Hospital, Singapore.

SUBJECTS

20 women admitted in early labour were randomly allocated to two groups.

INTERVENTIONS

Women in the first group had two catheters that had been tied together introduced transcervically into the same amniotic fluid pocket. The second group had two catheters introduced in different directions so that each catheter tip was in a different pocket of amniotic fluid.

MAIN OUTCOME MEASURE

The contraction to contraction pressure difference recorded by the two catheters in the same uterus. In addition, the cumulative uterine active pressure generated by one catheter was compared with that of the other.

RESULTS

There were differences in peak pressure of up to 4-5.3 kPa (30-40 mmHg) during some contractions. The difference in pressure recordings between the two catheters could not be explained by effects of loculation of amniotic fluid. However, the pressures recorded were not systematically higher in one catheter than in the other. Cumulative uterine activity was very similar when assessed by each catheter in the same uterus.

CONCLUSION

Intrauterine pressure measurements using transducer tipped catheters provide reliable information on the cumulative pressure wherever the catheter tip was sited in the uterus, but there are variations in pressures recorded during individual contractions.

Comparative study of 99mTc-HM-PAO SPECT brain imaging, EEG and CT scanning in epileptic patients during the interictal period

Forty patients with epilepsy in the interictal period were studied with 99mTc (HM-PAO) SPECT brain imaging, EEG and CT scanning. Four cases of generalized epilepsy had normal findings on EEG, SPECT imaging and CT scanning. Two cases of childhood benign partial seizures had abnormal EEG, but the SPECT brain imagings were normal. Regional hypoperfusions of various extents were found in 20 of the 34 patients with complex partial seizures. Among the 34 patients, 17 had abnormal EEG and 8 had abnormal CT scans. A good topographic concordance between regional HM-PAO hypofixation and EEG foci was found (39.1%). Localization of the lesion by SPECT imaging and CT scan was coincident in 5 cases (27.8%). The correlation between these three examination methods is discussed.

Smooth muscle tone and rapid resetting of rat aortic baroreceptors

Changes in conditioning mean arterial pressure (cMAP) selectively alter the set point of arterial baroreceptors and baroreflexes without affecting gain. Changes in smooth muscle tone at constant cMAPs shift the pressure-discharge curves of aortic baroreceptors in a similar manner. Using an in vitro preparation of the rat aortic arch, we tested whether near maximal changes in smooth muscle tone affect rapid resetting in single regularly discharging aortic baroreceptors. Discharge, pressure, and aortic diameter were simultaneously measured. By using vasoactive drugs (phenylephrine, angiotensin II, Bay K 8644, and nitroprusside), rapid resetting to cMAP changes was tested during different smooth muscle tone conditions (control, constricted, and dilated). Baroreceptor discharge-response curves were periodically assessed with slow ramps of increasing pressure at each of three different cMAP levels (10-15 minutes each). Rapid resetting relations were constructed for pressure threshold (Pth) and diameter threshold (Dth) plotted against cMAP and conditioning diameter (cD), respectively. Vasoconstriction decreased Pth in all baroreceptors (n = 13, p less than 0.05). Baroreceptor resetting ability as indicated by the slopes of the resetting relations (pressure- or diameter-resetting ratios, delta Pth/delta cMAP or delta Dth/delta cD, respectively) was unaffected by large increases in smooth muscle tone (p greater than 0.12). Vasoconstriction, however, offset the pressure-resetting relation, shifting the linear relation in a parallel manner to higher Pth values. In contrast, Dth values during vasoconstriction were not offset but instead fell along a single diameter-resetting relation coincident with the control relation for each baroreceptor. This last result suggests that acute alteration of vessel mechanics by vasoconstriction does not alter the basic rapid resetting process.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucagon administration to the rat via eye drops

Systemic absorption of glucagon from eye drops containing an emulsant caused an elevation in blood D-glucose concentrations in anesthetized rats. Glucagon (0.03 mg) delivered to the eye in buffered saline had no significant hyperglycemic action. However, delivery of glucagon in eye drops containing 0.25% saponin caused a rapid, dose-dependent increase in blood D-glucose values. Maximal absorption was observed 20 minutes after eye drop administration and values returned to baseline after 60 minutes. Immunoreactive glucagon levels measured 20 minutes after administration of eye drops containing saponin plus glucagon were increased by 2.4-fold compared to basal values. Glucagon administration via eye drops was ineffective when 0.5% Brij78 or BL-9 was substituted for saponin. These results demonstrate that in the rat, systemic absorption of glucagon delivered in eye drops is possible, but the choice of an emulsant may be critical.

FAB Assembly and Enrichment in a Monovalent Phage Display System

We have developed a system that allows the expression of a single copy of an antibody Fab molecule on the surface of the filamentous bacteriophage M13 and demonstrate the utility of this system for enrichment of specific "Fab phage". A "humanized" version of antibody 4D5 (h4D5) directed against the extracellular domain of the HER2 (neu) receptor, was used as prototype to assess the assembly of Fab molecules on the phage and to determine the power of the enrichment system. The h4D5 Fab phage showed specific binding to the extracellular domain of the receptor and exhibited an affinity for its antigen virtually identical to the Fab itself. By virtue of its antigen binding, the h4D5 Fab phage could be sorted from a million-fold excess of non-cognate Fab phage in only two rounds of sorting. Further experiments demonstrated that the h4D5 Fab phage could be preferentially enriched from mixtures of variant Fab phages that had lower affinities for the HER2 receptor.

Reliability of intrauterine pressure measurements

The reliability of intrauterine pressure measurements was studied by placing two catheters in the same uterus in women in labor. Nineteen parturients were studied, five with two Intran I catheters in different pockets of amniotic fluid, five with two Intran II catheters in different pockets, and nine with two Intran II catheters in the same pocket of amniotic fluid. Among 1429 contractions studied, the catheters showed differences of pressure of less than 5 mmHg in 86% of contractions and of less than 10 mmHg in 94%. When cumulative uterine activity was calculated for each labor, the difference in the total active pressures shown by the two catheters was less than 5% in 17 cases and 5% or more in two cases. These differences are unlikely to be of any importance in the management of labor.

Systemic absorption of insulin delivered topically to the rat eye

Insulin administration in eye drops containing 1% saponin caused a rapid and reproducible reduction in blood levels of D-glucose in anesthetized rats; insulin eye drops lacking saponin were ineffective. Systemic insulin absorption also was observed when Brij 78 or BL-9 was substituted for saponin in eye drops containing insulin. Nonanesthetized rats displayed lower initial D-glucose levels than anesthetized rats, and little hypoglycemic response to insulin eye drops could be observed, suggesting that counter-regulatory hormones could effectively counterbalance the influence of exogenous insulin on glycemic control. Streptozotocin-diabetic rats displayed elevated blood D-glucose values (greater than 400 mg/dl), and these values were decreased to 100-200 mg/dl after the administration of insulin in eye drop solutions containing saponin. The site of insulin absorption appears to be the nasolacrimal drainage system of the rat because administration of a solution containing insulin plus saponin directly into the punctum caused a rapid, significant decrease in blood D-glucose levels. The observation that insulin could be absorbed from the rat eye is consistent with the possibility that insulin eye drops containing an absorption-enhancing surfactant agent could be of potential benefit in the treatment of diabetes mellitus in humans.

[Quality of Chinese drug Halloysitum rubrum]

X-ray diffraction was used in analysing the constituents of Halloysitum rubrum. The results show that its composition is quite complicated and its colours are mainly due to the content of Fe.

Autoantibodies to serum proteins in women with recurrent spontaneous abortion: subsequent pregnancy outcome

Sera from 130 first trimester pregnant women were tested for their serum antibody level against a naturally occurring serum antigen purified from non-pregnancy sera. IgG and IgM antibody level was measured using enzyme linked immunosorbent assay. Results indicate that patients with multiple abortion (n = 26) have significantly (p = 0.0029) lower level of IgG antibody and significantly (p = 0.0001) higher level of IgM antibodies against the serum antigen as compared to the patients with successful pregnancies with no history of miscarriage (n = 63). Western blot analysis identified the serum antigen recognized by the IgM antibody as a 24 kDa molecular mass component. These IgG and IgM antibodies may play an important role in the outcome of pregnancy.

Immunologic characterization of a recombinant Kentucky bluegrass (Poa pratensis) allergenic peptide

A recombinant peptide of Kentucky bluegrass (KBG) pollen was synthesized as a fusion protein (FP) in Escherichia coli by recombinant DNA procedures and was compared with its natural counterparts with respect to its allergenic properties. The FP was demonstrated to bind to the IgE antibodies (Abs) of greater than or equal to 95% of 55 individual sera examined. A positive correlation (r = 0.90) was observed between the levels of IgE Abs corresponding to the FP and the grass-pollen extract(s). With sera of five allergic patients, the IgE binding of three different protein preparations were compared, namely, KBG pollen proteins, 27 to 35 kd gel-purified pollen proteins, and the FP. Results indicated that about 50% of the total IgE binding of KBG pollen proteins was due to the IgE Abs specific to FP. Comparison of the above protein preparations with respect to their abilities to specifically stimulate murine popliteal lymph node cells in vitro indicated that the total pollen proteins stimulated the highest proliferation of lymph node cells. Interestingly, the FP supported higher proliferation of lymph node cells than the gel-purified proteins. Collectively, these results suggest that the recombinant peptide constitutes a major allergenic constituent of grass pollens and may be of diagnostic and therapeutic value.

Uterine activity in dysfunctional labour and target uterine activity to be aimed with oxytocin titration

Uterine activity was quantified using a transducer tipped intrauterine catheter in 75 nulliparous women with dysfunctional labour. The active contraction area profiles in these women were below the median levels reported for those who had normal progress of labour from our institution. When uterine activity was augmented with oxytocin, 90.7% progressed in labour and delivered vaginally. Six patients (8%) showed poor progress despite good uterine activity and had to be delivered by caesarean section (CS) for failure to progress and signs of cephalopelvic disproportion. The pre- and post-augmentation uterine activity were similar in those who delivered vaginally or by CS and was not helpful in identifying those who had cephalopelvic disproportion. Of the 75 women who had slow progress of labour, 50 had a contraction frequency of less than 1 in 3 min whilst 25 had a minimum frequency of 1 in 3 min or more. All except one in the latter group delivered vaginally when oxytocin was titrated to achieve a contraction frequency of 1 in 2 to 2 1/2 min which were clinically judged to be adequate based on a duration greater than 40 sec. Oxytocin should be titrated to achieve a target contraction frequency of 1 in 2 to 2 1/2 min lasting greater than 40 sec to achieve good obstetric outcome in those with dysfunctional labour.

An SfiI restriction map of the Bacillus subtilis 168 genome

A restriction map of 24 SfiI (GGCCN4/NGGCC) restriction fragments has been constructed for the Bacillus subtilis genome. The combined sizes of the fragments indicate a genome size of approx. 4.2 Mb. The SfiI fragments range in size from 7-730 kb. Genetic markers have been located on 19 of the SfiI fragments, and 69 genetic markers have been assigned to the SfiI restriction map.

[The absorption of Fe, Zn, Cu in siwu, sijunzi, and Liuwei dihuang decoction by small intestine in rats]

In this study the absorption of Fe, Zn and Cu in decoctions of siwu decoction, sijunzi decoction and liuwei dihuang decoction by the small intestine in anesthetized rats was observed. The experimental results showed that the absorption of Cu and Fe from siwu decoction was much higher than that from other decoctions which might be related to the hematopoietic function of Cu and Fe rich in the decoction.

High-level expression in Escherichia coli and rapid purification of phosphatidylinositol-specific phospholipase C from Bacillus cereus and Bacillus thuringiensis

The construction of four vectors for high-level expression in Escherichia coli of the phosphatidylinositol-specific phospholipase C from Bacillus cereus or Bacillus thuringiensis is described. In all constructs the coding sequence for the mature phospholipase is precisely fused to the E. coli heat-stable enterotoxin II signal sequence for targeting of the protein to the periplasm. In one set of plasmids expression of the B. cereus or B. thuringiensis enzyme is under control of the E. coli alkaline phosphatase promoter, while in a second set of plasmids expression is under control of a lac-tac-tac triple tandem promoter. A simple and rapid procedure for complete purification of the phospholipase C overproduced in E. coli, involving isolation of the periplasmic proteins by osmotic shock followed by a single column chromatography step, is described. The largest quantity of purified enzyme, 40-60 mg per liter culture, is obtained with the plasmid expressing the B. cereus enzyme under control of the lac-tac-tac promoter. Lower quantities are obtained with the plasmids containing the alkaline phosphatase promoter (15-20 and 4-6 mg/liter for the B. cereus and B. thuringiensis enzymes, respectively) and with the plasmid expressing the B. thuringiensis phospholipase under control of the lac-tac-tac promoter (15-20 mg/liter). A comparison of the functional properties of the recombinant phospholipases with the native enzymes isolated from B. cereus or B. thuringiensis culture supernatant shows that they are identical with respect to their catalytic functions, viz., cleavage of phosphatidylinositol and cleavage of the glycosyl-phosphatidylinositol membrane anchor of bovine erythrocyte acetylcholinesterase.

The possible role of poroelasticity in the apparent viscoelastic behavior of passive cardiac muscle

This paper investigates the contribution of extracellular fluid flow to the apparent viscoelastic behavior of passive cardiac muscle. The muscle is modeled as an incompressible, isotropic, poroelastic solid saturated by an incompressible viscous fluid. Based on Biot's linear and nonlinear consolidation theories, solutions are presented for general time-dependent uniaxial loading of unconfined cylindrical muscle specimens. The nonlinear analysis includes the effects of large strain, material nonlinearity, and strain-dependent permeability. The computed results show that, for axial stretch ratios greater than 1.1, the changing permeability and the loading rate strongly affect the total stress relaxation and the short-time relaxation rate. Comparisons of theoretical and published experimental results show that extracellular fluid flow can account for several observed biomechanical features of passive myocardium, including the insensitivity of stress-strain curves to loading rate and of stress-relaxation curves to the amount of stretch. Theoretical hysteresis loops, however, are too small. Thus, both poroelastic and tissue viscoelastic effects must be considered in studies of passive cardiac muscle.

[Contents and solubilties of several elements in siwu decoction and liuwei dihuang decoction]

In this paper the contents and solubilities of copper, zinc, iron, calcium and magnesium in Siwu decoction and Liuwei Dihuang Decoction were studied. The results showed that there was a big difference in the solubilities of the elements among the crude drugs, and the increased solubilities of some elements in the simple recipe and compound prescription were an important factor for the effect of these decoctions. The increased solubilities of some elements might be one of the advantages for the compound prescription.

Medication compliance, antidepressant blood levels, and side effects in Southeast Asian patients

A study of medication compliance, side effects, and clinical change with the use of antidepressants in 32 Southeast Asian refugee patients seen at an urban mental health center is reported. Patients met criteria for either major depressive episode, posttraumatic stress disorder, or both. Only five of the 32 patients who stated that they were taking their medications regularly had antidepressant blood levels in the therapeutic range. Another 10 patients had subtherapeutic levels and the remaining 17 had undetectable blood levels. Patients with therapeutic blood levels had fewer side effects (p = 0.049) than patients with undetectable blood levels. Blood levels tended (p = 0.070) to be correlated with clinical improvement. The authors discuss cultural attitudes of Southeast Asian refugee patients toward medication use and side effects that appear to influence medication compliance.

The promoter of the glucoamylase-encoding gene of Aspergillus niger functions in Ustilago maydis

Promoter sequences from the Aspergillus niger glucoamylase-encoding gene (glaA) were linked to the bacterial hygromycin (Hy) phosphotransferase-encoding gene (hph) and this chimeric marker was used to select Hy-resistant (HyR) Ustilago maydis transformants. This is an example of an Ascomycete promoter functioning in a Basidiomycete. HyR transformants varied with respect to copy number of integrated vector, mitotic stability, and tolerance to Hy. Only 216 bp of glaA promoter sequence is required for expression in U. maydis but this promoter is not induced by starch as it is in Aspergillus spp. The transcriptional start points are the same in U. maydis and A. niger.

Cocaine inhibits baroreflex control of blood pressure by actions at arterial baroreceptors

Blood pressure and heart rate often increase during cocaine intoxication, but the mechanisms of these cardiovascular responses are poorly understood. The most often suggested theories are central nervous system mechanisms involving the blockade of neuronal transmitter uptake. Cocaine also has potent local anesthetic properties, and in this study we tested the possible role of peripheral actions of cocaine at baroreceptor afferents. Single fiber baroreceptors were recorded using an in vitro preparation of the rat aortic arch. Diameter, pressure, and baroreceptor discharge were recorded. Cocaine perfused through the lumen of the aortic arch at a suprathreshold pressure reduced baroreceptor discharge within 90 s of entering the lumen of the aorta. Slow ramps of pressure elicited complete pressure- and diameter-discharge curves every 5 min. Beginning at about 1 microM, cocaine inhibited baroreceptor function; threshold increased, the maximum discharge decreased, and at 100 microM cocaine, all discharge ceased. The vasodilator nitroprusside or the alpha 1-adrenoreceptor antagonist prazosin did not affect baroreceptor responses to cocaine. In in vivo tests in rabbits, cocaine that perfused through a vascularly isolated carotid sinus reduced the slope of the baroreflex relationship between carotid sinus pressure and systemic mean arterial pressure. Significant depression of baroreceptor function was found at concentrations similar to the plasma cocaine levels measured in clinical studies. The local anesthetic properties of cocaine may be involved in baroreceptor effects. Our studies suggest a possible contributing role of a new site of action of cocaine outside the central nervous system. Compromise of baroreceptor reflexes could facilitate the development of serious cardiovascular complications associated with cocaine abuse.

Angiotensin II and bradykinin stimulate phosphoinositide breakdown in intact rat kidney glomeruli but not in proximal tubules: glomerular response modulated by phorbol ester

We have investigated the effect of angiotensin II, bradykinin, insulin and insulin-like growth factor I on phosphoinositide turnover in intact rat glomeruli and tubules. Angiotensin II produced a dose-dependent increase in inositol monophosphate formation with an IC50 of 10(-7)M, when added to isolated rat glomeruli. Angiotensin II-stimulated inositol phosphates formation was inhibited by the angiotensin receptor antagonist [Sar-Leu8]angiotensin II, indicating that the above response was mediated through activation of an angiotensin receptor in intact glomeruli. Besides angiotensin, in intact glomeruli, only bradykinin stimulated a phosphoinositide response, while in intact proximal tubules, none of the agonists tested produced an activation of the inositol phosphate formation. Angiotensin II- and bradykinin-stimulated inositol phosphate accumulation in intact glomeruli was inhibited by phorbol myristate acetate, an activator of protein kinase C.

[Enhancement of absorption of tetramethylpyrazine by synthetic borneol]

Sprague-Dawley rats were given ig tetramethylpyrazine phosphate (TMP) 5 mg/kg with or without previous borneol 5 mg/kg. The plasma TMP concentrations were analysed by GC method, and the data were treated by NONLIN program. The Cmax were 931 and 562 ng/ml, respectively, (P less than 0.01); while the AUC were 68,849 and 37,174, respectively, (P less than 0.05). It is suggested that the borneol enhances the absorption of the TMP but not in elimination.

Depression and posttraumatic stress disorder in Southeast Asian refugees

The authors report on 404 Southeast Asian refugees seen at a community clinic. Approximately three-quarters of these patients met DSM-III criteria for major depressive episode, and 14% had posttraumatic stress disorder. Complaints of pain and sleep disturbances were the predominant presenting symptoms. Most of the men were married, but more than 40% of the women were widowed. Between 15% and 30% of the patients reported specific traumatic experiences either in their homeland or during their escape. Widowhood and such traumatic experiences were positively correlated with more symptoms of depression and anxiety.

Augmentation of labour: does oxytocin titration to achieve preset active contraction area values produce better obstetric outcome?

The value of quantifying active contraction area to guide oxytocin titration in augmentation of labour was investigated by a randomised trial. Sixty-eight nulliparae with slow progress of labour had oxytocin titrated to achieve preset "optimal" active contraction area or "optimal" frequency of contractions in a randomised manner. There was no difference in maternal characteristics of age and height, pre-augmentation period of observed labour or cervical dilatation at the onset of augmentation between the 2 groups. The maximum dose of oxytocin, post-augmentation period and the number of operative deliveries were similar. There was no difference in the mean birth weight of neonates, or in the number of neonates who had low Apgar score or acidotic cord arterial blood pH. Our results suggest that there may be no advantage in oxytocin titration to achieve preset "optimal" active contraction area compared with "optimal" frequency of uterine contractions in nulliparae with slow progress of labour.

Receptors for insulin and insulin-like growth factor-I in the human adrenal gland

Human adrenal glands contain high-affinity receptors for insulin and insulin-like growth factor I (IGF-I). Comparative studies with rat, hamster and human adrenal membranes confirmed that IGF-I receptors are most abundant in rat and hamster adrenals, whereas insulin and IGF-I receptors are present in equivalent numbers in human adrenal glands. Covalent crosslinking studies revealed that the human adrenal gland IGF-I receptor binding subunit migrated on dodecyl sulfate polyacrylamide gels with Mr = 135,000, which is identical to the migration of IGF-I receptor binding subunits isolated from other tissues. Autoradiography of frozen human adrenal slices incubated with [125I]insulin showed prominent, displaceable binding of this radioligand to the zona reticularis, zona glomerulosa, vasculature and medulla; in contrast, [125I]IGF-I binding to human adrenal tissue was most prominent in the zona reticularis and negligible in the medullary region.

Arterial baroreceptor resetting: contributions of chronic and acute processes

1. Pressure threshold (Pth) and suprathreshold pressure sensitivity (Sth) are important measures of the pressure-discharge characteristics of arterial baroreceptors. An in vitro preparation of the rat aortic arch-aortic nerve has been used to assess the influence of extracellular ion concentration, distensibility, smooth muscle activation and rapid resetting on single fibre baroreceptor discharge. 2. Changes in extracellular cations alter Pth and Sth in a reciprocal manner, suggesting that these two properties share common excitatory mechanisms probably at the level of membrane ion conductance channels. 3. During normal development and ageing in normotensive rats, Pth and blood pressure are fairly constant even during periods of greatly changing aortic distensibility. Sth increases progressively to maturity and then decreases somewhat with advanced age. 4. During hypertension, changes in distensibility in spontaneously hypertensive rats do not account for changes in Pth and Sth. 5. The capacity of arterial baroreceptors to rapidly reset during acute changes in the conditioning mean arterial pressure is not altered by chronic resetting, decreases in distensibility or by differences in the initial Pth or Sth of individual baroreceptors. 6. Within the maximal physiological or pathophysiological range, the prevailing or conditioning mean arterial pressure appears to be the most potent modulator of arterial baroreceptor discharge.

[Differences in length and weight growth patterns between urban and rural infants]

Mixed longitudinal data of length and weight growth from 595 rural and 337 urban infants were analysed. Count models were fitted to the means of length and weight in different ages, sexes and feedings separately. The curve fitting to the data was rather satisfactory. Comparison of model parameters between urban and rural infants suggested that rural infants had a higher length level at birth but lower accelerative growth afterwards than urban ones, which was even more obvious in breast-fed infants. The difference in birth weight between them was not significant; and the urban infants had a faster linear growth velocity than rural ones. These results might be caused by the fact that food supplementing in urban infants was significantly earlier and better than in rural ones.

Carcinoid tumor of the testicle

Carcinoid tumors commonly are found in the gastrointestinal tract; they rarely are found in the testicle. An illustrative case is presented and the entity discussed. Variables regarding prognosis are reviewed.

Interaction among unitary spike trains: implications for whole nerve measurements

Interaction among action potential trains was examined in electroneurograms (ENGs) from filaments containing several fibers. In an in vitro preparation, increasing aortic pressure generated trains of action potentials (spikes) from regularly discharging aortic baroreceptors. Multifiber records were electronically sorted, and spikes from each separate baroreceptor were identified. "True" discharge rates, measured as the instantaneous frequency of the sorted records, were compared with the results of three quantitation approaches commonly used for multifiber or whole nerve activity in mass ENGs: "spike" counts per unit time, ENG voltage integration, and normalizations of counts or integration. Even in ENGs containing only two active baroreceptors, numerous interactions of the two spike trains occurred. Of 33 paired recordings (66 baroreceptors), 77.3% of the individual baroreceptors had spike trains that could not be clearly discriminated because of interactions with signals from other baroreceptors. Virtually all baroreceptors (96.3%) in nine three-fiber ENGs (27 baroreceptors) showed evidence of missed spikes. Corrected or true spike rates were always greater than activity rates measured by simple counting. Similarity of discharge frequencies in the different baroreceptors was the most important determinant of the rate of voltage signal interaction. Simple count or integration methods underestimated slopes of pressure-response curves and peak activity values by 20-40% compared with sorted instantaneous frequency. Not all coincidence of action potentials in the ENG resulted in simple additions of peak voltages. We conclude that simple counting and integrative techniques substantially underestimate multifiber nerve activity and such quantitation techniques should be used cautiously, particularly in experimental comparisons across groups of animals.(ABSTRACT TRUNCATED AT 250 WORDS)

[A study on traditional processing methods using drug juice]

The traditional processing with drug juice has a long history, rich contents, rigid regularities and a variety of method. It is one of the important processing methods in Chinese medicine. To systematize and make better use of the traditional methods of processing drug juices, this paper has conducted an investigation from such angles as historical background, approximate rules of composing and clinical application.

Interaction between mitochondria and the nucleus

The interaction between the mitochondrial and the nuclear genome is in part mediated by proteins (and possibly also RNAs) which are encoded in the nucleus and imported into mitochondria. We are beginning to understand how proteins can penetrate across both mitochondrial membranes and how some of these proteins can regulate the expression of specific mitochondrial genes.

Import of proteins into yeast mitochondria: the purified matrix processing protease contains two subunits which are encoded by the nuclear MAS1 and MAS2 genes

We have purified the metalloprotease which is localized in the soluble matrix space of Saccharomyces cerevisiae mitochondria and cleaves the amino-terminal matrix-targeting sequences from imported mitochondrial precursor proteins. The enzyme consists of two loosely associated non-identical subunits of mol. wt 48,000 and 51,000, respectively. Attempts to separate the two subunits from each other caused loss of activity. The smaller subunit had been identified as the product of the nuclear MAS1 gene (Witte et al., 1988). The larger subunit is now identified as the product of the nuclear MAS2 gene.