A method for obtaining a pure population of t6/t6 mouse embryos prior to developmental arrest

Developmental delay, as the result of ovariectomy, causes mouse blastocyst embryos obtained from +/t6 inter se matings to separate into two distinct populations when placed into outgrowth medium. One population remains as free floating embryos for a significantly longer period of time than the other population. Based upon their phenotypic expression following attachment and outgrowth, the former population was considered to be composed entirely of t6/t6 embryos and the latter, to be composed of +/+ and +/t6 embryos (Nadijcka et al., '81). In the present study, two-dimensional gel electrophoresis identified the embryos which were delayed in attachment as t6/t6 embryos since they synthesize only p63/6.9a, a product of the Tcp-1a locus which is unique to t-haplotypes. The early attaching embryos, assumed to be +/+ and +/t6, synthesize both p63/6.9a and b. The p63/6.9b protein is coded for by Tcp-1b on the wild-type homologous chromosome. Control +/+ blastocyst embryos synthesize only p63/6.9b. The data show that t6/t6 embryos can be identified prior to their lethal period and, thus, subjected to comparative studies to determine the cause of their lethality. Developmental delay is the first method established to enable one to unambiguously identify t6/t6 embryos prior to developmental arrest.

[Preliminary study on soilless cultivation techniques of Panax quinquefolium L]

Our experiment has shown 1. Vermiculite with sand (volume 1:1) is a good substrate of soil for American Ginseng. The yield and contents of ginsenoside of American ginseng in this soilless substrate are a little higher than those in ordinary soil. 2. This kind of substrate can be used continuously with fewer occurrences of insect pest and plant diseases and contributes significantly to the reduction of production cost.

Preliminary clinical trials of a computer-based cardiac arrest alarm

The use of a high reliability cardiac arrest alarm utilising the continuously monitored values of patient heart rate and mean arterial blood pressure is described, based on a sample of 167 patients monitored for a total of 5116 h. The analogue heart rate and mean blood pressure signals are sampled at 1 s intervals, and a smoothing algorithm is applied to each of the resulting series which rejects artefacts, and identifies slope and step changes in each. Certain combinations of events in the 2 series, occurring within a preset time window, determine whether a cardiac arrest alarm or warning signal should be activated by the system. A total of 30 acute events occurring in 14 patients during the course of the study were each identified within 10 s. No cardiac arrest event was misdiagnosed by the algorithm during the period of the study. The algorithm also generates warnings which may have predictive value, and which will be the subject of further research. A final false alarm rate of about 1/200 h of monitoring was observed in adults (1/50 h in children), with evidence that these rates could be substantially improved.

[Effects of concentration and ratio of N, P and K on seedlings of Panax quinquefolium L]

Results of the orthogonal experiment of N, P and K are as follows: (1) The highest growth rate occurs in treatment 4 (N100ppm, P25ppm, K250ppm) and other features are also good. So this treatment can be used in hydroponics of seedling of P. quinquefolium. (2) The influences of N, P and K concentration on the contents of ginsenosides in different parts of seedling are different. The content of ginsenosides in aerial part is 14.72-16.72%, higher than 3.24-4.00% in root.

Thrombolysis using liposomal-encapsulated streptokinase: an in vitro study

The clot-lysing ability of streptokinase (SK) was examined using membrane-bound thrombi. Encapsulation of SK in large unilamellar phospholipid vesicles (liposomes) resulted in entrapping approximately 30% of its original activity. Measurements of streptokinase activity for liposomal-encapsulated streptokinase (LESK) indicated little loss of activity or leakage in Tris-buffered saline over a 24-hr period at temperatures of 4 and 23 degrees C. However, incubation of free SK and LESK in platelet-poor plasma (PPP) at 37 degrees C resulted in a decrease of SK activity. The retention of SK activity in LESK was considerably higher than that of unentrapped SK. Clot-dissolving time (CDT) was measured by monitoring the pressure drop during slow filtration in plasma through membrane-bound thrombi. The results indicated that both LESK and free SK were able to activate the fibrinolytic system. Without prior incubation in PPP at 37 degrees C, the CDT of a SK and PPP mixture (SK/PPP) was 10.7 +/- 1.9 min (n = 12), while that of a LESK and PPP mixture (LESK/PPP) was 12.4 +/- 1.7 min (n = 12). The CDT-detected clot-lysing abilities of both SK and LESK were diminished by incubation in PPP, but to different extents. After 15- and 30-min incubations, the CDT of SK/PPP increased significantly to 15.5 +/- 1.5 and 24.1 +/- 2.4 min (n = 5, P less than 0.05), respectively. In contrast, the CDT of LESK/PPP increased to 13.3 +/- 0.8 min (n = 5) after 15 min of incubation and to 16.0 +/- 1.1 min (n = 5, P less than 0.05) after a 30-min incubation. These results suggest that entrapment of SK in liposomes preserves the thrombolytic potential of the plasminogen activator by limiting its exposure to the components of the plasma.

Direct identification of Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare from amplified primary cultures in BACTEC media using DNA probes

DNA probes (Gen-Probe, San Diego, Calif.) directed at the Mycobacterium tuberculosis complex and Mycobacterium avium-M. intracellulare complex were used to identify acid-fast bacilli directly from specimens grown in BACTEC 12B bottles (Becton Dickinson and Co., Towson, Md.). Clinical specimens were inoculated directly or after decontamination into a BACTEC 12B bottle, Middlebrook 7H11 agar, and Lowenstein-Jensen medium. Conventional media were incubated at 37 degrees C in 5% CO2 and examined weekly for 6 weeks. Identification of isolates grown on conventional media by standard biochemicals, morphology, and growth characteristics served as the reference method for identification. BACTEC bottles were incubated at 37 degrees C, and a growth index was taken twice a week. When a growth index of greater than or equal to 100 was reached, 1 ml of BACTEC 12B medium was put into each of three microfuge tubes which were centrifuged for 15 min at 15,000 x g. Pellets were used in hybridization reactions with an M. tuberculosis complex probe, an M. avium probe, and an M. intracellulare probe. The results of the hybridizations of the three probes with the same sample were compared, and the highest percent hybridization was divided by the average of the lower hybridization values. If this value, the derived patient ratio (DPR), was greater than or equal to 3, then the specimen was considered positive for the organism giving the highest percent hybridization. Of the 1,988 specimens cultured, the results of conventional tests for the 190 conventional culture-positive specimens were 64 M. tuberculosis, 61 M. avium, 14 M. intracellulare, 30 other Mycobacterium spp., and 25 non-acid-fast bacilli. There were four cultures that each contained two different Mycobacterium spp. Directly probing the BACTEC 12B sediment, at DPR of >/= 3 the M. tuberculosis probe identified 83% (53 of 64) of M. tuberculosis isolates, the M. avium probe identified 92% (56 of 61) M. avium isolates, and the M. intracellulare probe identified 86% (12 of 14) of M. intracellulare isolates. There were no false-positive results at this DPR level. The false-negative results from probing the sediment from the BACTEC 12B bottle could not solely be attributed to the number of organisms present, the growth index, or antimicrobial therapy.

Ca2+-dependent structural changes in bovine blood coagulation factor Va and its subunits

The calcium dependence of the structures of bovine blood coagulation factor Va and its subunits (Vh and Vl) has been examined spectroscopically in order to characterize the conformational changes which accompany the binding of Ca2+ to Vh and Vl to form factor Va. The far-UV CD spectra of the isolated subunits indicate that the secondary structures of both Vh and Vl are predominantly beta-sheet (greater than 45%), with little alpha-helix content (less than 15%). No change in the far-UV CD spectrum was observed when factor Va was formed by the addition of Ca2+ to an equimolar mixture of Vl and Vh. Hence, no detectable change in secondary structure occurs during the formation of factor Va. In contrast, the addition of Ca2+ to an equimolar mixture of Vh and Vl caused a small (2%) increase in the total intrinsic fluorescence intensity and a blue shift in the emission spectrum that resulted from a tertiary structural change and/or the association of nonpolar surfaces at the subunit interface. This fluorescence change correlated closely with the appearance of functional factor Va, since the rate of the spectral change was the same as the rate of recovery of cofactor activity, and since both were half-maximal near 50 microM Ca2+. This fluorescence change required both subunits, was reversed by the addition of EDTA, and was observed only with metal ions that can substitute for Ca2+ in reconstituting factor Va activity from Vh and Vl (Mn2+ and Tb3+; not Mg2+). When a sample containing ANS (8-anilino-1-naphthalenesulfonate) and an equimolar mixture of calcium-free Vh and Vl was titrated with Ca2+, the ANS emission intensity decreased by about 30%, most likely because the association of Vl and Vh caused nonpolar regions at the subunit-subunit interface to become inaccessible for ANS binding. The calcium dependence of this spectral change yielded a Kd of 51 +/- 2 microM, and the rate of the decrease in ANS fluorescence occurred at nearly the same rate as the recovery of factor Va activity. Thus, both intrinsic and extrinsic fluorescence data, as well as other data, indicate that the calcium binding site in factor Va has an apparent Kd of 50 microM under our conditions and that the calcium-mediated binding between Vl and Vh involves hydrophobic interactions between the subunits.(ABSTRACT TRUNCATED AT 400 WORDS)

A microcomputer implementation of status and alarm algorithms in a cardiac surgical intensive care unit

Algorithms have been developed for monitoring the cardiovascular status of patients on their return to an intensive care unit after cardiac surgery and also for giving an immediate alarm of a critical deterioration in this status. The two systems for implementing these algorithms were initially developed on Z80 based microprocessor systems and preliminary clinical trials based on the resulting instruments proved encouraging. For further clinical trials of the algorithms the systems have been integrated and implemented on a BBC microcomputer with a 6502 second processor. The development and structure of the programs for implementing the algorithms are described, together with the program input and output facilities and diagnostic techniques used to analyse the information output from the program.

Synthesis and biological activity of highly potent octapeptide analogs of somatostatin

In the search for selective and long-acting analogs of somatostatin, nearly 200 compounds were synthesized by solid-phase methods, purified, and tested biologically. Among these octapeptides, some contained N-terminal (Formula: see text) were 177 times and 113 times more potent, respectively, than somatostatin in tests for inhibition of growth hormone release. These two octapeptides containing tyrosine and valine in positions 3 and 6, respectively, were more active and more selective than their Phe-3 and Thr-6 counterparts, D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-NH2 and D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Trp-NH2. D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2 was also about 6 times more potent than its L-Trp-4 diastereoisomer. The analogs D-Phe-Cys-Tyr-Lys-Val-Cys-Thr-NH2 and D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2 showed a prolonged duration of action and were able to inhibit growth hormone release for at least 3 hr. Analogs of both Phe-3/Thr-6 and Tyr-3/Val-6 classes also suppressed the release of insulin and glucagon in rats and pentagastrin-induced secretion of gastric acid in dogs, but their potencies in these tests were much smaller than the growth-hormone-release inhibitory activity. Some of these analogs possessed antitumor activities as shown by the inhibition of growth of animal models of prostate, mammary, and ductal pancreatic tumors.

Establishment of three human liver carcinoma cell lines and some of their biological characteristics in vitro

Three cell lines derived from liver carcinoma specimens of two male and one female operated patients have been successfully established in vitro and designated by the names of BEL-7402, BEL-7404 and BEL-7405. In the course of the establishment (from the 2nd transfer onwards) studies were made to characterize them. The doubling time of cell population was found to be 20--26 hr. They formed tumor nodules upon heterologous transplantation. They appeared as epithelial-like cells in morphology and showed, in addition to desmosomes, the presence of cytoplasmic tonofibrills which were typical of epithelial cells by electron microscopy. The ultrastructural features were different from normal human liver cells, but similar to clinical hepatoma cells. They had hypotriploid chromosone number with one abnormally long acrocentric chromosome present in all 3 cell lines and additional small acrocentric chromosome and chromosome fragment in BEL-7405 line of cells. AFP were detected intracellularly by the indirect immunofluorescent method. LDH isoenzyme showed a pattern different from that of human adult liver, but similar to those of embryonic liver and clinical hepatoma with the increase of the percentage of LDH-1 (H-type) at the expanse of LDH-5 (M-type), i.e. with a higher H/M ratio. The results suggest the 3 lines of liver carcinoma cells as rapidly growing and not well differentiated epithelial-like malignant cells.