[Concentrations and size distributions of aerosols in middle summer of Chengdu]

Statistical concentrations and size distributions of aerosols in middle summer of Chengdu city were measured by using optical scattering method. The influence of climate and its daily change affects on the concentration and distribution were analysed. The results showed: many of the distributions agreed with the Junge distribution; the peak concentration appeared near the noon; the relative humidity had strong influence on concentration; the clean-up effect of rain fall was evident. The measured results are useful for evaluating the environmental sanitation of the city.

Use of EPR oximetry with India ink to measure the pO2 in the liver in vivo in mice

The partial pressure of oxygen (pO2) of the liver in vivo in unanesthetized mice was determined using electron paramagnetic resonance (EPR) oximetry with India ink. The EPR spectra were obtained using a low-frequency (1.2 GHz) EPR spectrometer with a loop gap cavity resonator. The line width of the India ink used in this experiment was reversibly broadened by oxygen and was particularly sensitive to pO2 below 30 torr. After the administration of India ink into the tail vein, the India ink particles were taken up mainly by Kupffer cells in the liver and in part by phagocytes in the spleen. The pO2 measured in the normal liver was about 14 torr and was constant for the 2-week experimental period. The pO2 decreased when measured at 1, 2, and 6 days after treatment with hepatotoxin (carbon tetrachloride (CCl4)); within 2 weeks, it returned almost to the initial level. Measurements by EPR at sacrifice of controls and CCl4-treated mice indicated that more than 90% of the India ink went to the liver; the spleen contained 4.7% of total amount in control mice and 8.8% in CCl4-treated mice when measured 2 weeks after the treatment. These data indicate the usefulness of India ink for measuring the pO2 of the liver in vivo and that the pO2 in the Kupffer cells is decreased when the liver is damaged by CCl4.

The melanotropic peptide, [Nle4,D-Phe7] alpha-MSH, stimulates human melanoma tyrosinase activity and inhibits cell proliferation

Seventeen human melanoma cell (HMC) lines, both melanotic and amelanotic, were incubated in the continuous presence of a potent melanotropic peptide hormone analog, [Nle4,D-Phe7] alpha-MSH, for 72 hr with daily changes of medium. Only one cell line (HD, melanotic) consistently responded to the hormone analog by increased tyrosinase activity. Three (one melanotic, two amelanotic) of the HMC lines also failed to respond to the peptide by either increased or decreased enzyme activity when incubated continuously in the presence of the peptide for longer periods of time (6,15,27,43 days). The HD cell line, however, again responded with increasingly enhanced basal enzyme activity the longer the cells were incubated in the presence of the melanotropin. One amelanotic cell line (C8161) responded with enhanced enzyme activity when grown to confluency in the continuous presence of the peptide. Basal tyrosinase activity of the C8161 cell line may have increased as cell density in the flasks increased. These results suggest that under conditions of increased cell number, phenotypic expression of tyrosinase activity in so called "amelanotic" (tyrosinase-negative) cells is increased and can be enhanced further by stimulation with a melanotropic peptide. Under conditions of increased cell number, the presence of [Nle4,D-Phe7] alpha-MSH caused morphological differentiation (shape change); the cells became enlarged and very dendritic. The number of cells in monolayer (surface of the flask) and in the medium were drastically reduced in both melanotic and "amelanotic" cell lines incubated with [Nle4,D-Phe7] alpha-MSH. The data support other published reports that melanotropic peptides inhibit human melanoma cell growth (proliferation) in vitro, most likely through a cytostatic mechanism. [Nle4,D-Phe7] alpha-MSH also exhibited a prolonged (residual) inhibitory action on HD cell proliferation. In other words, inhibition of cell growth (proliferation) of the HMCs was evident even several days after removal of the melanotropic peptide from the incubation medium.

[Comparative study on pharmacological effects of various species of Pueraria]

Through comparative studies on the acute toxicity of four species of Pueraria, it was found that the toxicity of P. peduncularis was the highest, followed by P. lobata and P. omeiensis, and that of P. thomsonii was the lowest. The inhibitory effects of P. lobata, P. omeiensis and puerarin on the fever induced by 2,4-dinitrophenol in rats were very fast and significant, maintaining for about 8 hours, while the effect of P. thomsonii is relatively weak. As for influence upon the degrees of myocardiac ischemia induced by pituitrin, P. omeiensis appeared to be the most potent, and P. thomsonii the least one, while P. lobata and puerarin were intermediate between the above two. Summarily, the antipyretic and anti-myocardiac ischemia effects of P. lobata and P. omeiensis are stronger than those of P. thomsonii, and puerarin is one of their effective components.

Nonsusceptibility of the Honey Bee, Apis mellifera (Hymenoptera: Apidae), to Steinernematid and Heterorhabditid Nematodes

We exposed honey bee workers and brood to four entomopathogenic nematode species under conditions normally encountered in the hive by spraying nematodes onto combs. Mortality of adult bees exposed to any of the nematode species was less than 10%, and there was no evidence of nematode infection when dead adults were dissected. To assess the impact of nematodes on brood, we used smaller-size honey combs placed in the second story (super) of a hive and large brood combs placed in the main section of the hive. Our results were inconsistent between these two experimental designs. The smaller honey combs sprayed with Steinernema carpocapsae contained the largest number of uncapped ceils, those sprayed with Heterorhabditis baeteriophora or S. riobravis contained an intermediate number of uncapped cells, and control combs and those sprayed with S. glaseri contained the fewest nmnber of uncapped cells. Large combs sprayed with S. riobravis contained more uncapped ceils than controls or those sprayed with S. carpocapsae, although the differences were not significant. Our results do not support the hypothesis that high-temperature-tolerant species of nematodes are necessarily more infective to honey bees.

Assessment of cerebral pO2 by EPR oximetry in rodents: effects of anesthesia, ischemia, and breathing gas

This report describes experiments designed to assess and illustrate the effectiveness of a new method for the measurement of cerebral interstitial pO2 in conscious rodents. It is based on the use of low frequency electron paramagnetic resonance (EPR) spectroscopy with lithium phthalocyanine as the oxygen sensitive probe. Magnetic resonance imaging was used to document placement of the probe in the brain, and to assess potential cerebral changes associated with the placement. The technique provided accurate and reproducible measurements of localized pO2 in the brains of conscious rodents under a variety of physiological conditions and for time periods of at least 2 weeks. Using this approach we quantitated the depressing effects on cerebral pO2 of three representative anesthetics, isoflurane, ketamine/xylazine, and sodium pentobarbital. The effects of changing the content of oxygen in the breathing gas was investigated and found to change the cerebral pO2. In experiments with gerbils, crystals of lithium phthalocyanine were implanted in each side of the brain and using a one-dimensional magnetic field gradient, simultaneous measurement of pO2 values from normal and ischemic (ischemia induced by unilateral ligation of a carotid artery) hemispheres of the brain were obtained. These results demonstrate that EPR oximetry with lithium phthalocyanine is a versatile and useful method in the measurement of cerebral pO2 under various physiological and pathophysiological conditions.

Mild hyperthermia can induce adaptation to cytogenetic damage caused by subsequent X irradiation

Many low-level environmental agents are able to induce an increased resistance to subsequent mutagenic effects induced by ionizing radiation. In this paper, an induced cytogenetic adaptation to radiation in human lymphocytes was studied with mild hyperthermia as the adaptive treatment and compared with that induced by low-dose radiation. We found that this adaptation could be induced not only in PHA-stimulated human lymphocytes (at 14, 38 and 42 h after addition of PHA), but also in unstimulated G0-phase cells (before addition of PHA) by mild hyperthermia (41 degrees C for 1 h) as well as 50 mGy X rays. When the two adaptive treatments were combined, no additive effects on the magnitude of the adaptation induced were observed, suggesting that low-dose radiation and hyperthermia may share one mechanism of induction of adaptation to cytogenetic damage. Some mechanisms which may be involved in the induction of adaptation to cytogenetic damage by low-dose radiation are discussed and compared with the effects of mild hyperthermia in inducing thermotolerance and radioresistance.

Regions of the JAK2 tyrosine kinase required for coupling to the growth hormone receptor

Growth hormone (GH) treatment of cells promotes activation of JAK2, a GH receptor (GHR)-associated tyrosine kinase. We now explore JAK2 regions required for GHR-induced signaling. Wild-type (WT) JAK2 and JAK2 molecules with deletions of the amino terminus (JAK2ATD), carboxyl terminus (JAK2CTD), or kinase-like domain (JAK2PKD) were each transiently coexpressed in COS-7 cells with the rabbit GHR. The following responses were assayed: GH-induced transactivation of a luciferase reporter governed by a c-fos enhancer element; GH-induced shift in the molecular mass of a cotransfected epitope-tagged extracellular signal-regulated kinase molecule; and GH-induced antiphosphotyrosine immunoprecipitability of the transfected JAK2 form. In each assay, WTJAK2 and JAK2PKD allowed GH-induced signaling, whereas JAK2ATD and JAK2CTD did not. Anti-GHR serum coimmunoprecipitated WTJAK2, JAK2PKD, and JAK2CTD, but not JAK2ATD. Finally, a chimera in which the JAK2 kinase domain replaced the GHR cytoplasmic domain signaled GH-induced transactivation. We conclude: 1) kinase-like domain deletion eliminates neither physical nor functional interaction between JAK2 and the GHR; 2) kinase domain deletion eliminates functional but not physical coupling of JAK2 to the GHR; 3) interaction with the GHR appears dependent on the NH2-terminal one-fifth of JAK2; and 4) a GH-responsive signaling unit can include as little as the GHR external and transmembrane domains and the JAK2 kinase domain.

Randomized case-controlled trial of oral low-dose acyclovir for prevention of virus infections in recipients of renal allografts

A randomized case-controlled trial of oral low-dose acyclovir (600-800 mg per day) has been conducted for the prevention of virus infections in 66 recipients of renal allografts since 1990. In comparison with the untreated controls, acyclovir could prevent herpes virus simplex (HSV), reduce morbidity of pneumonia from 10 cases (30%) to 3 cases (9%) (P < 0.05) and lower CMV-IgM positive rate from 30% to 12%. Serum Cr and BUN in acyclovir group were lower than those in control group. These results strongly suggested that oral administration low-dose acyclovir could prevent virus infections after renal transplantation.

Detection of short-lived free radicals by low-frequency electron paramagnetic resonance spin trapping in whole living animals

We report the direct observation of sulfur trioxide anion free radical (SO3.-) from the body of live mice by using a low-frequency (1.2 GHz, L-band) EPR spin trapping method. Intraperitoneal injection of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) (15 mmol/kg) used as trapping agent was followed by sequential iv injections of sodium sulfate (2-5 mmol/kg) and sodium dichromate (0.3 mmol/kg). The mouse was placed in an L-band loop gap resonator. The observed spectra consisted of two superposed components: DMPO/SO3.- (alpha N = 14.0, alpha H = 16.0) and Cr(V) (g = 1.9798). The time course for the generation and reduction of DMPO/SO3.- was followed. The signal intensity reached a maximum at about 7 min. In vitro experiments carried out at 9.15 GHz confirmed the production of SO3.- under the conditions used for in vivo studies; the hyperfine splittings of DMPO/SO3.- produced in the in vitro experiments were the same as those produced in the in vivo studies. The production of SO.-3 is supported by oxygen uptake studies, which show that the prior addition of 300 mM DMPO inhibits oxygen consumption by SO3.-.

Metaphase and interphase fluorescence in situ hybridization mapping of the rice genome with bacterial artificial chromosomes

Fluorescence in situ hybridization (FISH) is a powerful tool for physical mapping in human and other mammalian species. However, application of the FISH technique has been limited in plant species, especially for mapping single- or low-copy DNA sequences, due to inconsistent signal production in plant chromosome preparations. Here we demonstrate that bacterial artificial chromosome (BAC) clones can be mapped readily on rice (Oryza sativa L.) chromosomes by FISH. Repetitive DNA sequences in BAC clones can be suppressed efficiently by using rice genomic DNA as a competitor in the hybridization mixture. BAC clones as small as 40 kb were successfully mapped. To demonstrate the application of the FISH technique in physical mapping of plant genomes, both anonymous BAC clones and clones closely linked to a rice bacterial blight-resistance locus, Xa21, were chosen for analysis. The physical location of Xa21 and the relationships among the linked clones were established, thus demonstrating the utility of FISH in plant genome analysis.

Direct preparation and meiotic analysis of human semen

A meiotic study of human semen specimens was carried out in 60 cases. Among them, 20 were normal controls, 20 suffered from infertility, and 20 had a history of recurrent spontaneous abortions. Of the cases of infertility and abortion, 50% were found to have numerical and/or structural chromosomal aberrations in spite of the normal blood karyotype. It is suggested that chromosomal aberrations may be the cause of sterility and abortion. The success rate of semen chromosome G-banding in the infertility, abortion and control groups was 70%, 55% and 25% respectively. The semen samples of three cases of heterozygous carriers with reciprocal chromosomal translocation were also studied. The ring quadrivalents were identified in all cases. The results may explain the recurrent abortions in these patients.

Role of changes in renal hemodynamics and P-450 metabolites of arachidonic acid in the reversal of one-kidney, one clip hypertension

OBJECTIVE

To examine the role of changes in renal hemodynamics and P-450 metabolites of arachidonic acid in the reversal of one-kidney, one clip (1-K,1C) hypertension in rats.

DESIGN

The stimulus for the release of an antihypertensive lipid from the kidney is not known. This study examined whether cortical or papillary blood flow is altered after removal of the clip from the renal artery of 1-K,1C hypertensive rats, and the effects of blockade of the renal metabolism of arachidonic acid by P-450 with 17-octadecynoic acid (17-ODYA) on the fall in blood pressure.

METHODS

Cortical and medullary blood flows were measured using laser-Doppler flowmetry. 17-ODYA (33 nmol/min) was infused directly into the renal artery to examine the effect of inhibition of renal P-450 activity on reversal of 1-K,1C hypertension. The renal metabolism of arachidonic acid in control and in 1-K,1C hypertensive rats was assessed by incubating microsomes with [14C]-arachidonic acid, the metabolites formed being measured using reverse-phase high-performance liquid chromatography. The antihypertensive effects of these P-450 metabolites of arachidonic acid were compared with those of medullipin I after intravenous administration in conscious spontaneously hypertensive rats (SHR).

RESULTS

Cortical and papillary blood flow increased significantly and arterial pressure fell after unclipping the renal artery in the 1-K,1C hypertensive rats. 17-ODYA prevented the fall in blood pressure after unclipping. The production of epoxy- and dihydroxy-eicosatrienoic acids was elevated in microsomes prepared from the renal cortex of the 1-K,1C hypertensive rats. However, intravenous administration of these metabolites did not mimic the effect of medullipin I to lower arterial pressure in SHR.

CONCLUSION

Elevations in renal cortical or papillary blood flow, or both, may stimulate the release of a P-450-derived antihypertensive lipid from the kidney after unclipping of the renal artery in 1-K,1C hypertensive rats. However, it is unlikely that this substance is a P-450 metabolite of arachidonic acid.

Clinical measurement of mucosal wave velocity using simultaneous photoglottography and laryngostroboscopy

Simultaneous glottal transillumination or photoglottography (PGG), electroglottography (EGG), and video laryngostroboscopy were used to measure the traveling wave velocity of the vibrating vocal folds during phonation in human subjects. The duration of travel was calibrated from the PGG signal, while the displacement of the upper and lower lips of the vibrating vocal folds was calibrated from parallel laser beams projected onto the vocal folds. The mucosal wave velocity varied with the portion of the glottal cycle. The amplitude of displacement correlated positively with the intensity of phonation and negatively with the fundamental frequency and was decreased for breathy and pressed phonation modes. The velocity of the opening phase segment of the PGG signal directly correlated with the top lip displacement of the vibrating vocal fold, and bottom lip displacement correlated with the closing phase of the PGG signal. Therefore, with suitable calibration, the effects of mucosal lateral displacement may be measured from a PGG signal. Simultaneous measures of PGG, EGG, and stroboscopy provide a three-dimensional representation of glottal vibration that can be numerically analyzed.

[Acute effect of milrinone on pulmonary hemodynamics in patients with hypoxic pulmonary hypertension]

Milrinone is a phosphodiesterase inhibitor that has vasorelaxant activity. The authors studied its effect on pulmonary haemodynamics in 12 patients with hypoxic pulmonary hypertension. After treatment with milrinone, mean pulmonary arterial pressure (from 4.61 +/- 1.41 kPa to 3.36 +/- 1.20 kPa, 1kPa = 7.5mmHg) and pulmonary vascular resistance (from 557.56 +/- 167.70 dyne.sec.cm-5 to 392.60 +/- 133. 81 dyne.sec.cm-5) decreased (P < 0.05), while cardiac output increased (from 5.11 +/- 1.62 L/min to 5.62 +/- 1.66 L/min) (P > 0.05). The systemic blood pressure (from 11.50 +/- 1.63 kPa to 10.71 +/- 1.83 kPa) and systemic vascular resistance (from 1476.64 +/- 531.52 dyne.sec.cm-5 to 1,236.49 +/- 410.18 dyne.sec.cm-5) also decreased (P > 0.05). but there was no change in arterial oxygen saturation (SaO2). The incidence of side effects were low, 4 patients developed tackycardia, and 2 patients developed ventricular premature beats. It is therefore, shown that milrinone is a potent pulmonary vasodilator.

An analysis of the effects of eddy currents on L-band EPR spectra

Recently, impressive results have been obtained with EPR studies of living animals and perfused organs using low-frequency EPR. In many instances in such studies, however, there are apparent distortions of the spectra. The shapes of these spectra and theoretical considerations indicate that these effects are due to eddy currents in the moderately conductive biological materials. Therefore the effects of eddy currents produced in biological samples under typical conditions being employed for in vivo EPR studies have been systematically studied in order to determine the extent of these effects and to develop methods for compensating for these effects. The presence of eddy currents was found to decrease the Q factor and distort the shapes of the EPR spectra. The distortion of the spectra led to linewidth broadening, changes in peak heights, and shifts of the apparent center of the lines. These effects could be corrected instrumentally, but this was effective only when signals have a high S/N. The use of appropriate computer simulations, based on linear combinations of the expected absorption and dispersion signals, can effectively correct for the effects of eddy currents and provide accurate data on the parameters of EPR spectra that are needed for most or all of the analyses used in biological studies of animals and tissues at low frequencies.

[Surgical treatment of carcinoma of low rectum]

1230 cases of low rectal cancer were treated surgically from 1954 through 1990 with a resectability rate of 79.92% and a curative resectability rate of 63.98%. Among curative resections, abdomino-perineal excision accounted for 71.16% and sphincter-saving resection for 28.84%. Before 1980, 19.19% cases were treated with SSR and since 1980 it was raisen to 41.04%. In comparison of the results of group before 1980 with those since 1980, the mortality rate of curative resection was 1.56% and 0.99% respectively. The 5-year survival rate of curative resection (life table method) was 58.96% +/- 2.87% in APR and 80.39% +/- 5.06% in SSR before 1980, and 71.65% +/- 3.28% in APR and 83.82% +/- 3.46% since 1980. The local recurrence after curative resection was 13.57% in APR and 12.33% in SSR. The data showed that in properly selected cases, the outcome was better in SSR than in APR either in survival or in quality of life. The feasibility and reasonality of the SSR and the rules for selecting the operative procedures in low rectal cancer were discussed in detail.

Protein kinase A and hedgehog signaling in Drosophila limb development

The Drosophila hedgehog (hh) gene encodes a secreted protein involved in organizing growth and patterning in many developmental processes. Hh appears to act by inducing the localized expression of at least two other signaling molecules, decapentaplegic (dpp) and wingless (wg), which then govern cell proliferation and patterning in surrounding tissue. Here, we demonstrate that cyclic AMP (cAMP)-dependent protein kinase A (PKA) is essential during limb development to prevent inappropriate dpp and wg expression. We also show that a constitutively active form of PKA can prevent inappropriate dpp and wg expression, but does not interfere with their normal induction by hh. We propose that the basal activity of PKA imposes a block on the transcription of dpp and wg and that hh exerts its organizing influence by alleviating this block.

In vivo oximetry using EPR and India ink

Recent advances in electron paramagnetic resonance (EPR) oximetry have established the use of the particulate materials fusinite and lithium phthalocyanine (LiPc) as probes for measurement of oxygen tensions in tissues in vivo with a sensitivity and accuracy that is relevant for studying pathophysiological processes. India ink, another potentially very useful new probe for EPR oximetry, shares the critical properties of fusinite and LiPc and has the additional advantage of already having been widely used clinically with no apparent toxicity. The line width is particularly sensitive to changes in oxygen tension of less than 30 mmHg; in this range the line broadening/unit of pO2 is much greater than that of fusinite and LiPc. Over the range of biological conditions that can occur in vivo, the response of the EPR spectrum of India ink to pO2 is independent of pH, oxidants, reductants, and the nature of the medium. In this paper we describe the relevant properties of India ink and its use to measure pO2 in vivo in experimental animals and a human subject.

Low-frequency EPR study of chromium(V) formation from chromium(VI) in living plants

The reduction of Cr(VI) by green algae and higher plants was investigated using a low-frequency EPR spectrometer equipped with an extended loop gap resonator. Incubation of algae (Spirogyra and Mougeotia) with Cr(VI) generated both Cr(V) and Cr(III). The maximum Cr(V) signal was observed in about 10 minutes. Incubation of Cr(VI) with oat, soybean, and garlic generated Cr(V). The maximum Cr(V) peak appeared after more than 10 hours of incubation, and Cr(V) was located predominantly in the roots. The Cr(V) peak exhibited hyperfine splittings of about 0.79 gauss, typical of the Cr(V) complexes with diol-containing molecules. The results suggest that the reduction of Cr(VI) to lower oxidation states by living plants may provide a detoxification pathway for Cr(VI) in ecological systems. The results also indicate that low-frequency EPR may be used to investigate the metabolism of paramagnetic metal ions in intact plants.