[Screening of strain producing extracellular penicillin acylase]

Ninety-eight strains having extracellular penicillin acylase activity were derived from soil samples by colour-developing method. 10 strains of them possess higher activity of penicillin acylase. All of those are found to be Bacillus megaterium. The optimum condition of enzyme production was investigated with the strain No. 46 which is from No. 247 by single colony isolation. The productivity of penicillin acylase in the optimum condition have been enhanced 2.5 times more than that in the screening condition. The mutant strain, Bacillus megaterium UL-81, which penicillin acylase activity reached the level of 723u/100ml of broth was obtained from No. 46 by treatment with physical and chemical factors. The penicillin acylase activity of UL-81 can reach 820u/100 ml in 500L fermentor. The mutant strain differed from parent strain in the morphology of colony, the size of cells, the effect of concentration and the addition time of phenylacetic acid on the production of penicillin acylase.

[Biotransformation of zearalenone]

The conversion of Zearalenone by some strains of microorganisms was investigated. When the selective strains of Rhodotorula sp., Arthrobacter sp., Saccharomyces sp., and Candida sp. were incubated by shaking or standing at 28 degrees C for 72 h with an alcoholic solution of Zearalenone as the substrate at a concentration of 2-10 mg/ml ethanol (50-100 micrograms/ml medium), it was readily converted to give Zearalenols, consisting either mainly of the alpha-isomer (e.g. 96% in case of Rhodotorula sp. and 84% in case of Arthrobacter sp. as determined by HPLC) or beta-isomer (e.g. 91% and 92% in Saccharomyces sp. and Candida sp., respectively). The structure of the product was confirmed by 13C-NMR, MS and HPLC.

Transitional mucosa at anastomosis. A cause of local tumor recurrence in patients with rectal cancer after anterior resection

Transitional mucosa adjacent to colorectal cancers is essentially characterized by an excess of sialomucins at the expense of the normally predominant sulphomucins in epithelial cells lining the intestinal crypts which presents the early stage of oncogenic transformation of colorectal epithelium. The presence or absence of sialomucins at the resection margins was studied histochemically using the high iron diamine-alcian blue(HID-AB) stain in 64 rectal cancer patients in Dukes' B stage who underwent curative anterior resection. The correlation was revealed between the presence of sialomucins at the resection margins and subsequent development of local tumour recurrence. Fourteen of 27 patients (51.9%) with sialomucins predominant pattern at either resection margin developed local recurrence compared with 4 of 37 patients (10.8%) with sulphomucins predominant pattern (P less than 0.001). It is suggested that determination of the transitional mucosa around anastomosis in patients treated for the rectal carcinoma by anterior resection appears to identify those with a higher risk of local recurrence.

Taurine and niacin offer a novel therapeutic modality in prevention of chemically-induced pulmonary fibrosis in hamsters

The bleomycin (BL)-hamster model of interstitial pulmonary fibrosis (IPF) is generally associated with increased lung lipid peroxidation, measured as malondialdehyde equivalent (MDAE), calcium and collagen content; and superoxide dismutase (SOD), prolyl hydroxylase (PH) and poly(ADP-ribose) polymerase activities. We found that combined treatment with taurine in drinking water (1%) and niacin IP (250 mg/kg) daily, significantly decreased the BL-induced increases in lung MDAE and calcium content, and SOD, PH and poly(ADP-ribose) polymerase activities. This treatment almost completely ameliorated the BL-induced increases in the lung collagen accumulation as well. Findings of a similar nature were also demonstrated when taurine (2.5%) and niacin (2.5%) were supplemented in the diet of hamsters used in the same BL model of IPF. The diet supplemented with taurine (2.5%), niacin (2.5%), or taurine (2.5%) + niacin (2.5%) also reduced AD-induced increases in lung collagen accumulation, phospholipids, MDAE and SOD activity. It was concluded that diet supplemented with taurine and/or niacin would completely or partially ameliorate chemically-induced pulmonary fibrosis.

Raman spectroscopic analysis of mo/si multilayers

Raman spectra are reported from MoSi2 polycrystalline powder and soft x-ray Mo/Si multilayers. The sharp lines at 323 and 438 cm-1 are all due to crystalline MoSi2. These lines in the powder sample intensify with annealing. The Raman spectra of as-deposited multilayers shows a broad asymmetric peak, highest at about 480 cm-1. We attribute this to α-Si which is highly disordered. In contrast to α-Si in semiconductor/semiconductor and semiconductor/dielectric multilayers, in the Mo/Si samples the Raman signal can vanish after modest heating. This provides evidence that the composition of the silicon component of the multilayer changes even with 200°C annealing. Further annealing also produces the signature for crystalline MoSi2 in the multilayer samples. This is the first report of the characterization of Mo/Si soft x-ray multilayers by Raman spectroscopy, and it indicates that Raman spectroscopy may be an effective technique for characterizing these soft x-ray multilayers and may be useful in studying their interfaces.

Properties of spontaneous inward currents recorded in smooth muscle cells isolated from the rabbit portal vein

1. Characteristics of spontaneous transient inward currents (STICs) which produced membrane depolarization were analysed with the perforated patch technique in single smooth muscle cells isolated from the rabbit portal vein. 2. In K(+)-free solutions the amplitude of STICs was linearly related to membrane potential and the reversal potential (Er) was -3.0 +/- 0.9 mV. Replacement of external NaCl with NaI shifted Er to -40.0 +/- 1.0 mV. Substitution of external NaCl by NaSCN also moved Er to negative values but replacement of sodium with Tris and choline did not change Er. It is concluded that STICs are generated by an increase in chloride conductance. 3. STICs were abolished or reduced by the chloride channel antagonists anthracene-9-carboxylic acid (1 mM) and 4-acetamido-4'-isothiocyanato-2,2'- stilbene-disulphonic acid (2 mM). 4. STICs were blocked by noradrenaline and caffeine which deplete intracellular calcium stores. This effect was reversible and this result indicates that the primary trigger for STICs is calcium released from intracellular stores and therefore STICs are calcium-activated chloride currents (ICl(Ca)). 5. Removal of calcium from the bathing solution abolished STICs in six out of seven cells but STICs persisted in Ca(2+)-free solution in one cell. When STICs were abolished in Ca(2+)-free external solution the size of the internal calcium store, as estimated from the noradrenaline-induced ICl(Ca), was not altered. It appears that an influx of calcium is usually necessary for STICs to be observed. 6. The frequency and amplitude of STICs were not altered by the voltage-dependent calcium channel antagonist cadmium (1 mM). However, in some quiescent cells influx of calcium through voltage-dependent channels did activate STICs. 7. It was concluded that in isolated portal vein cells STICs represent a Ca(2+)-activated chloride current which leads to spontaneous depolarization of the membrane and may play an important physiological or pathophysiological role to produce smooth muscle contraction.

Photodynamic therapy with chlorins for diffuse malignant mesothelioma: initial clinical results

Four patients underwent intraoperative photodynamic therapy after surgery with meso-tetra-(hydroxyphenyl)-chlorin (mTHPC-PDT) for diffuse malignant mesothelioma. Preliminary procedures were performed in two patients in order to establish the efficacy of mTHPC-PDT and to optimise its tumoricidal effect. The tumoricidal effect was related to the mTHPC dose, light dose and the time interval between sensitation and activation. 0.3 mg kg-1 mTHPC activated after 48 h with 10 Joules cm-2 of non-thermal laser light at 650 nm resulted in a 10 mm deep tumour infarction, due to tumour vessel necrosis and thrombosis. The mTHPC tissue concentration was up to 14 times higher in the tumour than in normal tissues. Skin photosensitivity was mild, dose dependent and occurred 3 to 10 days after administration of mTHPC. According to the results obtained, intraoperative mTHPC-PDT was performed following pleuropneumonectomy in two, pleurectomy and lobectomy in one and pleurectomy in one patient. Ten Joules cm-2 were delivered to the diaphragm and the costophrenic sulcus and 5 Joules cm-2 to the remaining thoracic cavity. The postoperative course was marked by loss of appetite, fluid retention, hypoproteinemia and severe chest pain. One patient succumbed from aspiration pneumonia. The remaining patients developed no neural or vascular alterations and no bronchial stump insufficiency during follow-up. mTHPC-PDT following surgical tumour resection deserves further evaluation in good risk patients with diffuse malignant mesothelioma.

[The influence of sodium ferulate on hypotensive effect and urinary excretion of TXB2 after captopril in essential hypertensive patients]

In the present study, the influence of sodium ferulate (SF) on hypotensive effect and urinary excretion of TXB2 after captopril (CAP) was observed in 44 patients with essential hypertension. A single oral dose of CAP (50 mg) decreased mean arterial pressure (MAP) from 16.25 +/- 0.85 to 13.65 +/- 1.14 kPa, n = 28, (P less than 0.01), and increased urinary TXB2 excretion significantly from 119.12 +/- 57.12 to 183.32 +/- 78.61 pg/min, n = 16, (P less than 0.05). The administration of SF 300 mg/d for one day did not affect the MAP. CAP in combination with SF induced a decrease both in MAP from 16.33 +/- 1.14 to 13.83 +/- 1.77 kPa, n = 16, (P less than 0.01) and urinary TXB2 excretion from 155.89 +/- 69.64 to 133.43 +/- 60.01 pg/min, n = 16, (P greater than 0.05) though the latter was not so significant. Compared with the administration of CAP alone, the combination of CAP and SF induced stronger hypotensive effect (P less than 0.05) and the increased urinary TXB2 excretion could be inhibited by SF, but the inhibition to angiotensin converting enzyme was the same. These results suggested that the increased urinary TXB2 excretion by CAP can be inhibited and the hypotensive effect of CAP is potentiated by SF in essential hypertensive patients.

[Clinical significance of length of rectal margins. Difference between intraoperation and fixation with formalin]

The minimal safe margin of resection is often considered 2-3 cm distal to a rectal tumour. However this margin length can change greatly depending on the time when it is measured. The change of the rectal length was observed in 6 persons during and after resection and in the specimen fixed with formalin. The rectal segment was longer after resection and shorter when fixed with formalin than its original in vivo length. A close correlation of the length of the rectum was found between intraoperation and postresection or fixation with formalin. So, the actual length of distal margin of anterior resection varied dramatically depending upon the time and method by which the margin was determined. Clinicopathological data from different groups were comparable with the linear correlation established in this study.

[Study on determination of ammonia-nitrogen in water by ammonia gas sensor electrode]

A method for the determination of NH3-N content in water by ammonia gas sensor electrode was studied systematically. Good results were obtained by adding acid to water samples until pH less than 2 for storage and adding EDTA to prevent metal ions from interference. Recoveries varied in the range of 90-104%, and the coefficients of variation less than or equal to 3.4%. The measurement range was 10(-1)-10(-4)micrograms/ml, and the detection limit 0.13 micrograms/ml. The reliability of the method was confirmed by comparison with Nesslerization (P greater than 0.5). This method is simple, rapid, accurate and can directly be applied to the determination of the content of ammonia-nitrogen in colored and turbid water samples.

Antagonistic effects of dihydropyridines and verapamil on CaCl2 and 5-HT-evoked contraction in porcine coronary artery

In porcine coronary arterial strips, the antagonistic effects of nifedipine (Nif), nimodipine (Nim), nicardipine (Nic), felodipine (Fel), and verapamil (Ver) to CaCl2-evoked contraction in Ca(2+)-free, K(+)-depolarized solution were greater than that to 5-HT. The order of potency (pD2') was Nif (9.1) greater than Fel (8.4) greater than Nim (7.9) greater than Nic (7.8) greater than Ver (7.2) to CaCl2 and Nif (8.3) greater than Nim (7.5) greater than Fel (6.8) greater than Ver (5.6) greater than Nic (5.3) to 5-HT. Ver inhibited 2 components of 5-HT-evoked contraction in Ca(2+)-free solution, but Fel inhibited only extracellular Ca(2+)-dependent contraction, suggesting that their action modes are different.

Identification of tyrosine 67 in bovine brain myelin basic protein as a specific phosphorylation site for thymus p56lck

The protein-tyrosine kinase p56lck exhibits a restricted substrate specificity in vitro but can efficiently phosphorylate bovine myelin basic protein (MBP). Results obtained from both peptide mapping and fast atom bombardment mass spectrometry indicate that tyrosine 67 in the sequence -Thr-Thr-His-Tyr67-Gly-Ser-Leu-Pro-Gln-Lys- in bovine MBP is the specific phosphorylation site. p56lck does not phosphorylate the acidic, cytoplasmic domain of erythrocyte band 3. In contrast, p40, another protein-tyrosine kinase purified from bovine thymus that readily phosphorylates band 3, does not phosphorylate MBP. Therefore, MBP and band 3 may prove to be useful substrates for distinguishing between various tyrosine kinases on the basis of substrate specificity. In addition, identification of the recognition sequence in MBP for p56lck may contribute to an understanding of the structural features of physiological substrates for this kinase.

Modulation of noradrenaline-induced membrane currents by papaverine in rabbit vascular smooth muscle cells

1. The modulation of noradrenaline-induced membrane currents by papaverine was studied with the nystatin whole-cell technique in freshly isolated rabbit ear artery and portal vein cells. 2. At a holding potential of -50 mV (in potassium-free conditions), papaverine inhibited the Ca(2+)-activated inward chloride current ICl(Ca) evoked by ionophoretic application of noradrenaline in rabbit portal vein cells in a concentration-dependent (10(-5)-10(-4) M) manner. 3. With potassium-containing solutions (at 0 mV) 10(-4) M-papaverine reversibly abolished the Ca(2+)-activated outward potassium current IK(Ca) induced by noradrenaline in both protal vein and ear artery cells. Occasionally, 10(-4) M-papaverine itself activated IK(Ca) before it abolished the response to noradrenaline. 4. Higher concentrations of papaverine (up to 10(-3) M) always evoked both ICl(Ca) and IK(Ca) at -50 and 0 mV respectively, before it abolished these responses to noradrenaline in both ear artery and portal vein cells. In the presence of 10(-3) M-papaverine higher doses of noradrenaline evoked the non-selective cation current in some portal vein cells. 5. In the presence of 10(-2) M-caffeine, which elicited both IK(Ca) and ICl(Ca), papaverine (10(-3) M) failed to activate either current and 10(-3) M-papaverine reduced the caffeine-induced IK(Ca) by 94%. In contrast, IK(Ca) induced by the calcium ionophore ionomycin was unaffected by papaverine. In Ca(2+)-free, 1 mM-EGTA external solutions, 10(-3) M-papaverine still induced IK(Ca) and blocked the response to noradrenaline. 6. The alpha 1-adrenoceptor antagonist prazosin (5 x 10(-8) M) completely blocked the noradrenaline-induced IK(Ca) but currents evoked by papaverine (10(-3) M) were unaffected by prazosin. 7. It was concluded that papaverine modulated noradrenaline-induced membrane currents in vascular smooth muscle cells by releasing and depleting caffeine-sensitive intracellular Ca2+ stores.

[An analysis of incidence mortality and survival rates of lung cancer in Beijing]

In the past 30 years the lung cancer incidence rate in the countries all over the world has been on increase. A population-based cancer registry has been set up since 1976 in Beijing. The epidemiological features of lung cancer in Beijing during 1977-1986 were analysed. The data collected show that the lung cancer incidence and mortality ranked first among cancers at all sites and had been on increase from year to year. The annual average crude incidence rate of cancer was 31.3/100000 in male during 1982-1984, the world standard rate was 33.0/100000. Incidence due to lung cancer accounted for 20.3% of all male cancer cases. The crude incidence rate was 22.8/100000. Incidence due to lung cancer accounted for 16.1% among all female cancer cases. The sex ratio of the world standard incidence rates was 1.56. The lung cancer is one of the lesser prevised cancer and the five year relative survival rate is 6.5% for both sexes in 1982-1983. The lung cancer mortality rate in Beijing urban area is compared with other countries in the world, and it is found that the female mortality rate of lung cancer in Beijing is the highest.

Combined detection of phenotype and Y chromosome by immunoenzyme labelling and in situ hybridisation on peripheral lymphocytes

A novel staining method for simultaneously determining the immunophenotype and sex of peripheral lymphocytes is described. Cell surface markers on lymphocytes are identified using specific monoclonal antibodies located by a peroxidase anti-peroxidase staining technique (PAP). Lymphocytes are subsequently hybridised with a biotinylated Y chromosome-specific sequence probe and this is located by avidin-biotin-alkaline phosphatase staining. Following the two staining steps the preparation is examined and in the same field lymphocytes show brown peroxidase staining of cell surface markers and red staining of the Y chromosome. The application of this combined staining technique provides a convenient method for studying the development of different cell lineages following sex-mismatched bone-marrow transplantation and for the identification of chimeric situations. The method has been shown to be sensitive and reproducible.

Noradrenaline-evoked cation conductance recorded with the nystatin whole-cell method in rabbit portal vein cells

1. Noradrenaline-evoked currents were studied with the perforated patch technique (nystatin in the patch pipette) in freshly dispersed rabbit portal vein cells. 2. With potassium-containing solutions noradrenaline produced an inward current at -50 mV and an outward current (IK(Ca] at 0 mV. In potassium-free conditions noradrenaline elicited two distinct membrane currents which could be differentiated according to their sensitivity to the presence of caffeine in the bathing solution. One current was blocked whereas the second response was unaffected by caffeine. 3. The reversal potential (Er = -2.0 mV) of the caffeine-sensitive current was altered when external chloride was replaced with more permeant anions but Er was not changed when external sodium was replaced by Tris. Therefore the caffeine-sensitive current appears to be a calcium-activated chloride current (ICl(Ca]. 4. Er (+6.0 mV) of the caffeine-insensitive current was not altered by anion substitution but was changed when external sodium was replaced by Tris and barium ions. Thus the caffeine-insensitive conductance is a non-selective cation current (Icat). 5. When external NaCl was replaced by BaCl2, Er was shifted to more positive potentials which suggests that the cation conductance is more permeable to barium than to sodium. Icat was not affected by 10(-6) M-nifedipine. 6. The steady-state current-voltage relationship was linear between -50 and +50 mV for ICl(Ca) but the cation conductance mechanism displayed pronounced inward rectification and little outward current flowed across the membrane at positive potentials. 7. Caffeine (which releases calcium from internal stores) and the calcium ionophore ionomycin, which are expected to increase intracellular calcium concentration, evoked ICl(Ca) but not Icat. Thus ICl(Ca) but not Icat can be activated directly by an increase in intracellular calcium concentration. 8. When calcium was removed from the bathing solution the amplitude of Icat was not altered at early times in Ca(2+)-free conditions but was abolished after 10 min. Icat was readily activated by noradrenaline in the presence of ionomycin, which inactivated ICl(Ca). A permissive role for calcium in the generation of Icat is suggested. 9. The times between the application of noradrenaline and the onset of the chloride and cationic conductances were similar (0.75 and 0.9 s respectively). In contrast the rise time (3.9 s) and half-decay time (11 s) of Icat were much longer than the corresponding values of ICl(Ca) (respectively 1.9 and 2 s). In high-barium solution noradrenaline sometimes evoked a response that lasted for up to 10 min.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of central RAS on one-kidney Grollman hypertension in rats and its mechanism

The effect of central renin-angiotensin system (RAS) on one-kidney Grollman hypertension during the maintaining phase and its mechanism were investigated in rats. The arterial blood pressure (ABP) and the content of angiotensin II (A II) and norepinephrine (NE) in brain regions was measured respectively. 4 weeks after operation the ABP was elevated significantly, and it sustained at high level 8 weeks post-operatively. However, ABP in the control group underwent no significant changes at the same period. The A II and the NE content in the brain regions of the operated group were significantly higher than in those of the age-matched control group. During the maintaining phase of hypertension captopril (150 micrograms/10 microliters) was injected into the lateral cerebroventricle at 0.5 h, 1.0 h and 1.5 h respectively, and ABP and content of A II and NE were determined at the corresponding time. The results showed that the above three parameters decreased consistently at 0.5 h and 1.0 h, and increased gradually at 1.5 h, suggesting that the central RAS might play an important role in the maintaining phase of one-kidney Grollman hypertension in rats.