Restriction enzyme SnaBI is sensitive to methylation of cytosine within its recognition sequence

Images

The characterization of IBF as a new selective dopamine D-2 receptor imaging agent

The in vivo and in vitro studies of a new iodinated benzamide analog, [125I]IBF,5-iodo-7-N-[(1-ethyl-2-pyrrolidinyl)methyl]carboxamido-2,3- dihydrobenzofuran as a potential central nervous system (CNS) D-2 dopamine receptor imaging agent were investigated. In vivo biodistribution of IBF in rat indicated that this agent concentrated in the striatum region and displayed a remarkably high target-to-nontarget ratio (striatum/cerebellum = 48 at 120 min post-injection). The in vitro binding studies suggested that IBF binds selectively to D-2 dopamine receptors with high affinity and low nonspecific binding (Kd = 0.106 +/- 0.015 nM, Bmax = 448 +/- 18.2 fmole/mg protein). Ex vivo autoradiography results in rats further confirmed the high uptake and retention of this agent in the basal ganglia region. The planar images of monkey brains (lateral view of the head) after i.v. injection of [123I]IBF clearly demonstrated that D-2 dopamine receptors can be visualized. With the excellent in vivo stability to deiodination and high target-to-nontarget ratio, [123I]IBF may be useful as a CNS D-2 dopamine receptor imaging agent for single photon emission computed tomography (SPECT) in humans.

Interactions of tazobactam and clavulanate with inducibly- and constitutively-expressed Class I beta-lactamases

Clavulanate and tazobactam (YTR 830) were tested as inhibitors and inducers of the AmpC-type Class I beta-lactamases of Pseudomonas aeruginosa, Enterobacter cloacae, Citrobacter freundii, Serratia marcescens, Morganella morganii and the Ic beta-lactamase of Proteus vulgaris. Both clavulanate and tazobactam inhibited the Pr. vulgaris Class Ic beta-lactamase and potentiated ticarcillin and piperacillin against beta-lactamase derepressed variants of this species. Tazobactam, but not clavulanate, also had some ability to inhibit the AmpC Class I enzymes of M. morganii, C. freundii, Ps. aeruginosa, E. cloacae and S. marcescens. The piperacillin + tazobactam combination, unlike ticarcillin + clavulanate, showed some degree of synergy against most derepressed strains of these species. This behaviour partly depended upon the greater inhibitory activity of tazobactam for the enzymes, but also on piperacillin being easier to potentiate than ticarcillin. The synergy between piperacillin and tazobactam was greatest for M. morganii and C. freundii, least for Ps. aeruginosa and E. cloacae. Unfortunately, it is in the last two species that these enzymes pose the greatest resistance threat. Tazobactam caused little or no antagonism of piperacillin against beta-lactamase inducible species, whereas clavulanate antagonized ticarcillin against beta-lactamase inducible strains of E. cloacae and M. morganii (not other species). The antagonism of ticarcillin was attributable to beta-lactamase induction. The lack of antagonism with the tazobactam+piperacillin combination was related to tazobactam being a weaker inducer than clavulanate, not to piperacillin being less susceptible to antagonism than ticarcillin.

[Changes in RBC Ca2(+)-ATPase activity and red-cell calcium concentration during dialysis in patients with uremia]

The changes of RBC Ca2(+)-ATPase activity and red cell calcium concentration during dialysis were observed in 19 patients with uremia. The results showed that in 12 patients treated by haemodialysis the RBC Ca2(+)-ATPase activity was lowered an average of 35 U than that in the controls (P less than 0.001); whereas red cell calcium was increased about 5 times (P less than 0.001). After a four-hour haemodialysis, the Ca2(+)-ATPase activity increased 20 U (P less than 0.05); and red cell calcium decreased 45 mumol/L cells (P less than 0.05). In 7 patients treated by CAPD the RBC Ca2(+)-ATPase activity was reduced to 60% of that in the controls (P less than 0.001); and red cell calcium was about 5 times as high as that in the controls (P less than 0.001). After one month of CAPD, the Ca2(+)-ATPase activity increased only 10 U (P greater than 0.05); but red cell calcium decreased 66 mumol/L cells (P less than 0.01).

Purification of an acrosomal antigen recognized by a monoclonal antibody and antifertility effects of isoimmune serum

A highly conserved acrosomal antigen reactive to a monoclonal antibody (HS-63), generated against human sperm, was purified to homogeneity with a combination of conventional procedures and immunoaffinity chromatography using a soluble extract of mouse and rabbit testes. The molecular weight of the purified antigen was 42-50 kD when analysed by sodium dodecylsulphate polyacrylamide gel electrophoresis. The high specificity of the purified antigen to monoclonal antibody HS-63 was shown by indirect immunofluorescent inhibition assay, enzyme-linked immunosorbent assay, Western blot analysis and radioimmunosorbent assay. The purified antigen was used for isoimmunization of mice and rabbits. Following successive immunizations, antisera of high titres were raised and reacted specifically with antigen on the sperm acrosome and in testes of several mammalian species, but not with somatic tissues. These isoimmune sera exhibited strong inhibition on mouse in-vitro fertilization and human sperm penetration of zona-free hamster eggs. The results of this study suggest that the sperm-specific acrosomal antigen reacting with HS-63 could be a good candidate for the development of immunocontraceptive vaccines in humans and in other animals.

Laser-assisted reconstructive vascular surgery

To clarify the efficacy of laser-assisted reconstructive vascular surgery (LARVS) for patients with severe symptoms of peripheral arterial occlusive disease, 118 ischemic legs of 104 patients were retrospectively analyzed (argon:89 and YAG:29 lasers). Of those 118 legs, 26 (22%) had tissue loss, 60 (51%) had rest pain, and 32 (27%) had incapacitating intermittent claudication. The LARVS was adequate in 60 of 118 (51%) and inadequate in 58 of 118 (49%). With argon:89 and Nd:YAG:29 lasers, respectively, 41 of 89 (46%) and 19 of 29 (66%) were adequate. In the superficial femoral artery (SFA) and popliteal artery (PA), the LARVS was adequate in 31 of 43 (72%) in segmental occlusion and in one of 31 (3%) in total-length occlusion (p less than 0.001). In segmental occlusion of the SFA, however, argon:89 and Nd:YAG:29 lasers were adequate in four of 12 (33%) and in 10 of 12 (83%), respectively (p less than 0.05). The legs in which laser was used in more than one artery (eight of eight) or in occluded grafts (proximal SFA to distal PA; three of 18) required amputation within 30 days. A follow-up study demonstrated patency in 31 of 34 (91%) 1-24 months later with the argon:89 laser and in 15 of 16 (94%) 1-6 months later with the Nd:YAG:29 laser. This study indicates that LARVS was adequate in segmental occlusions, particularly in SFA and PA lesions; however, total-length occlusions and combination arterial lesions were not appropriate for the currently available laser systems. Laser application should not be performed if a guidewire passes through the lesion, since these lesions may be more appropriately treated with balloon angioplasty.

[Clonidine stimulates central nervous alpha 2 adrenoceptors not mediating Ca2+ channels]

Seven renal hypertensive (2 kidneys--2 clipped) and 8 normotensive conscious dogs were given icv clonidine. After the medication the mean arterial blood pressure (MAP) were lowered and the heart rate (HR) and plasma norepinephrine (NE) were decreased. The magnitude of the decrease of MAP was greater than normotensive dogs; while no differences of decrease of NE was found. Nicardipine (10 micrograms/kg) icv caused significant increases of MAP and HR in both hypertensive and normotensive groups. The decrease of MAP induced by clonidine was not changed by the pretreatment of nicardipine icv in both groups. It is thus concluded that clonidine stimulates central nervous alpha adrenoceptors not mediating Ca2+ channels.

[The relation between pathologic factors of esophagus cancer and prognosis of its sufferers: application of Cox's model]

Yanting and Langzhong counties in Sichuan Province are among the areas with highest esophagus cancer mortality in China. We collected 218 patients who received only surgery from 1972-1981 in Yanting Cancer Research Institute and had followed up till 1986. The data includes the survival time, age, cancer size and some other pathological factors, 11 in total. By using the self-compiled software SURVIVAL, we found 5 factors affected the prognosis of esophagus cancer sufferers significantly, i.e. age, cancer size, invasion depth, pattern of growth and fibrous encapsulation. The model is lambda(t,X) = lambda 0(t) exp (.0264 x2 + .165 1x4 + .639 7x8 + .353 2x9 - .753 9x11). We can estimate lambda 0(t) either parametrically or nonparametrically. For example, using the Weibull full-parametric model, the estimation is: lambda 0(t) = .0008133 t0.2716 with the full--parametric model, the survival function for different Prognosis Index I(X) can be estimated conveniently. Here I(X) = .026 4x2 + .165 1x4 + .639 7x8 + .353 2x9 - .753.9x11. Because of the use of the compiled BASIC program with Chinese explanation, the SURVIVAL is convenient to use and the speed is 4-5 times greater than explained BASIC.

Rapid effects of the flavonoid EMD 21388 on serum thyroid hormone binding and thyrotropin regulation in the rat

Naturally occurring and synthetic flavonoids are potent inhibitors of thyroid hormone 5'-deiodination and binding to human serum transthyretin (TTR) in vitro. We now describe the inhibitory effect of the most potent flavonoid, 3-methyl-4',6-dihydroxy-3',5'-dibromo-flavone (EMD 21388), on the serum protein binding of T4 and T3 and subsequent alterations of pituitary-thyroid function in the rat. Eight to 10 mumol/liter EMD 21388 added to pooled rat serum completely displaced [125I]T4 or [125I]T3 binding from TTR, the major thyroid hormone-binding protein in the rat, and markedly increased the percentages of free T4 and T3, measured by equilibrium dialysis. One to 4 h after the ip administration of 2 mumol EMD 21388/100 g BW to euthyroid rats, [125I]T4 and [125I]T3 binding to TTR decreased, serum T4 and T3 concentrations decreased, and the percentages of free T4 and free T3 increased. No changes were observed in the free T4 and free T3 concentrations. Serum TSH concentrations decreased at 1 h and were very low thereafter. EMD 21388 administration did not affect the elevated serum TSH concentrations in hypothyroid rats, strongly suggesting that the flavonoid does not directly affect TSH secretion. No changes were observed in hepatic type I 5'-deiodinase in euthyroid rats and pituitary type I and type II 5'-deiodinase in euthyroid and hypothyroid rats after EMD 21388 administration. We conclude that the ip administration of EMD 21388 to euthyroid rats inhibits T4 and T3 binding to TTR, with subsequent increases in the percentages of free T4 and free T3 and decreased serum T4 and T3 concentrations. The decrease in the serum TSH concentration was possibly due to transcient increases in the serum free T4 and/or free T3 concentrations, resulting in increased pituitary thyroid hormone content.

Interactions of FCE 22101 with class I beta-lactamases

Hyperproduction of chromosomal Class I beta-lactamase causes resistance to newer cephalosporins in Enterobacter cloacae, Citrobacter freundii, Serratia spp. and indole-positive Proteeae. We examined the interactions of FCE 22101 with these enzymes, measuring (i) antibiotic lability to pure enzyme, (ii) inducing power and (iii) activity against beta-lactamase-inducible strains and their -depressed and -basal mutants. Turnover numbers of FCE 22101 were between 0.7 and 1.5 molecules hydrolysed/min/enzyme molecule, compared with ranges of 0.5-40 for cefotaxime (950 for the Proteus vulgaris cephalosporinase) and 4400-22,000 for cephaloridine. FCE 22101 induced enzyme synthesis strongly below the MIC and antagonized labile weak inducers such as cefotaxime and mezlocillin. Like imipenem, but unlike newer cephalosporins, FCE 22101 had equal activity against inducible strains and derepressed mutants, and did not significantly select derepressed mutants from inducible populations. beta-Lactamase basal mutants of E. cloacae and C. freundii were four- to eight-fold more sensitive than inducible and derepressed organisms whereas beta-lactamase-basal, -inducible and -derepressed Proteeae and Serratia spp. were equally sensitive. This difference reflected the larger amounts of enzyme produced by the E. cloacae and C. freundii strains, rather than kinetic differences in enzyme activity.

Spatial properties of disparity pooling in human stereo vision

The spatial limits of disparity averaging were investigated using Julesz random dot stereograms with two different depth planes. Such stimuli could be perceived as two separate surfaces, one of which was seen through the transparent veil of the other, but under some conditions the depth of information provided by the two surfaces was pooled and the resulting surface was seen at the average of the local disparities. Two types of model are considered for disparity averaging. In the first, disparity averaging occurs as a consequence of attraction/repulsion effects in the disparity domain or as an interpolation process working on a dense depth map of the image. In the second, disparity averaging is seen as a consequence of monocular spatial filtering of the left and right eye images prior to binocular combination.

Nuptial and childbearing customs of the ethnic minorities in China

The current nuptial customs of the ethnic minorities in China are examined. "Although monogamous marriage has now been adopted by all but a few ethnic communities, variations still exist between different nationalities in the specific forms of marriage and range of intermarriage owing to the uneven nature of historical development. Such variations are shaped by various factors of the given locality and given time such as the socioeconomy, religion, culture and education, and exert direct influence on the childbearing behavior and reproduction of the ethnic population."

Prevention of invasive bacterial diseases by immunization with polysaccharide-protein conjugates

Covalent binding of CPS to T cell-dependent carrier proteins to form conjugates can be done by clinically acceptable methods. As a component of a conjugate, two immunologic properties of CPS are changed: 1) their immunogenicity is increased and; 2) reinjection induces a booster response in the young (T cell-dependence). Serum antibodies induced by the CPS alone, or as a component of a conjugate, are qualitatively similar: the difference between antibodies elicited by the CPS or the conjugate is quantitative. A clinical trial with a Hib-DT conjugate showed that conjugates could confer immunity in an age group not protected by the CPS alone. (table; see text) Induction of serum CPS antibodies confers protection against capsulated bacteria in the bloodstream: their role in the interaction of these pathogens on the mucous membranes has not been characterized. Preliminary in vitro experiments suggest that secretory antibodies to non-capsular structures may also exert protective immunity.

DNA gyrase binds to the family of prokaryotic repetitive extragenic palindromic sequences

A family of repetitive extragenic palindromic (REP) sequences is composed of hundreds of copies distributed throughout the chromosome. Their palindromic nature and conservation suggested that they are specifically recognized by a protein(s). We have identified DNA gyrase [DNA topoisomerase (ATP-hydrolysing), EC 5.99.1.3] as one of the REP-binding proteins. Gyrase has at least a 10-fold higher affinity for DNA containing REP sequences than for DNA not containing REP sequences. Binding effectiveness correlates directly with the number of REP sequences in the DNA. DNase I footprinting shows that gyrase protects 205 base pairs on a REP-containing DNA fragment enclosing the REP sequences. In agreement with the above results, a comparison of the REP consensus sequence with the sequence of previously identified pBR322 "strong" gyrase cleavage sites reveals a high degree of homology. Because REP sequences are numerous and found throughout the genome, we suggest they have physiological functions mediated through their interaction with gyrase, such as being sites of action for the maintenance of DNA supercoiling. In addition, we speculate that these interactions may be of a structural nature, such as involvement in the higher-order structure of the bacterial chromosome.

A new DNA immune adsorbent for hemoperfusion in SLE therapy: a clinical trial

This investigation studied the preparation and clinical trial of DNA immunoadsorbent for hemoperfusion in systemic lupus erythematosus (SLE) therapy. DNA was complexed with blue tetrazolium (BT), then mixed with collodion, and finally adsorbed on macroporous spherical polymeric adsorbent. The percentage of DNA thus immobilized was 98-98.5%, and no release was detected during hemoperfusion. A patient with severe SLE was treated with the above adsorbent in hemoperfusion. The patient was in coma, with high anti-DNA antibody and abnormal immune complex levels, which fell sharply from 56.34% to 0.8% after 2.5 h of whole-blood hemo perfusion. There were no major clinical complications, and 2 weeks later, her proteinuria level became normal and immune complex levels were sustained. She was then discharged from the hospital and has been in good health for more than 1 year.

Experimental study of morphological changes after gastroplasty

Twelve rabbits were sacrificed one and three days, one, two, four and eight weeks after horizontal gastroplasty in order to investigate morphological changes after operation. Histology of the proximal pouch of the stomach showed various degrees of mucosal damage and a close relationship between its severity and high pH of the pouch. This suggested the usefulness of pH measurement of the gastric juice in the proximal pouch as an indicator of mucosal damage after gastroplasty.

Activity of temocillin and other penicillins against beta-lactamase-inducible and -stably derepressed enterobacteria

MICs of temocillin, carbenicillin, ticarcillin, mezlocillin, piperacillin and ampicillin were determined for mutant series of Enterobacter cloacae, Citrobacter freundii, Proteus vulgaris, Morganella morganii and Serratia marcescens with inducible, stably derepressed or basal expression of chromosomal Class I beta-lactamases. Ampicillin was inactive (MIC greater than 256 mg/l) both against beta-lactamase-inducible organisms (except C. freundii) and their stably derepressed mutants, whereas basal mutants were sensitive (MIC 2-8 mg/l). Carbenicillin, ticarcillin, mezlocillin, piperacillin (and ampicillin for C. freundii) were active against both inducible and basal organisms (MIC less than 16 mg/l), but inactive against the derepressed mutants (MICs usually greater than 64 mg/l). Temocillin inhibited all the organisms, including the stably derepressed mutants, at 16 mg/l. Derepressed S. marcescens, M. morganii and Pr. vulgaris were as susceptible as the inducible strains and basal mutants. MICs of temocillin for derepressed mutants of E. cloacae and C. freundii were 4-16 fold above those for their inducible parent strains, but remained within the clinical range.