Sapporo-like human caliciviruses are genetically and antigenically diverse

The Sapporo-like human caliciviruses (HuCVs) comprise one of three genogroups of HuCVs associated with acute gastroenteritis. Phylogenetic analysis has shown that Sapporo-like HuCVs are related more closely to animal caliciviruses than to other known HuCVs. We produced 3.2 kb cDNA fragments from the 3' end to three Sapporo-like HuCVs that were associated with acute gastroenteritis in children (Houston/86, Houston/90, and London/92). Sequence analysis of the 3.2 kb cDNAs showed that two of the three viruses had a genomic organization similar to that of other Sapporo-like strains and the third strain (London/92) lacked an open reading frame overlapping the 5' end of the capsid gene. Alignment of the capsid sequences of these three strains showed 44-78% amino acid identity among the three strains. Phylogenetic analysis of the aligned sequences indicated the three strains are related but each belongs to a distinct genetic cluster. The genetic differences are associated with antigenic differences in that an enzyme immune assay (EIA) specific for the prototype Sapporo/82 strain detected the Houston/86 strain, but not the Houston/90 and London/92 strains. In vitro transcription and translation of viral cDNA containing the predicted capsid gene of Houston/90 resulted in a protein of 63 K, which is immunoprecipitated by sera from children infected with the strain. Genetically and antigenically distinct strains in the Sapporo-like HuCVs have not been described previously and the occurrence of such diverse strains in the same community likely increases the importance of these strains as a cause of illness in children.

[Determination of triptolide in extract from leigongteng (Tripterygium Wilfordii Hook. F.) by RP-HPLC]

A reversed-phase liquid chromatographic method has been developed and validated for the analysis of triptolide in extract from Leigongteng (Tripterygium Wilfordii Hook. F.). The drugs were eluted with petroleum-ethyl acetate on a neutral alumina cartridge and then measured by HPLC using a Hypersil C18 column and acetonitrile-water (40:60, V/V) mobile phase. Triptolide was quantified by ultraviolet absorbance at 210 nm. The method proved to be linear in the range of 0.25-4.00 mg/L with a regression coefficient of 0.9997. The lower limit of detection of triptolide was 0.1 mg/L. Intra-day and inter-day coefficients of variation of assay for triptolide were 1.9%-6.5% (n = 5) and 2.7%-7.8% (n = 5), respectively. The recoveries of the method were 89.8%-92.0%.

[Yishen huanshuai recipe retard progression of chronic renal failure]

OBJECTIVE

To investigate the effect of Yishen Huanshuai recipe (YSHSR) on the progression of chronic renal failure (CRF).

METHODS

Forty-six patients with CRF were divided into two groups: group A (self-controlled group, n = 18), whose treatment was subdivided into two stages. During the first stage, the patients treated with low protein diet and controlling blood pressure, while in the second stage, YSHSR was given. Group B(n = 28), whose treatment plan was similar with that of group A in second stage. The rate of progression of CRF was estimated by slope of the creatinine reciporcal (dl/mg) with time (month).

RESULTS

Mean slope of the creatinine reciprocal with time from the group A during the first stage was -0.0104 +/- 0.0021, while during the second stage, it was -0.0034 +/- 0.0018. There was significant difference between them (P < 0.05). Mean slope from the group B was -0.0047 +/- 0.0020. There was also significant difference between that from the group B and that from the group A during the first stage (P < 0.05).

CONCLUSIONS

Low protein and controlling blood pressure plus YSHSR therapy could markedly retard the rate of progression of CRF.

[Determination of felodipine concentration in human plasma by GC-ECD and study of its pharmacokinetics]

A rapid, accurate and sensitive gas chromatographic method using electron-capture detector (GC-ECD) was developed for the determination of felodipine concentration in human plasma. Nimodipine was used as internal standard. The plasma samples were extracted using a mixture of ethyl ether and n-hexane (2:1) to give mean recoveries of 97.3% of felodipine. The extracts were separated by a 5% SE-30 glass packed column (2 m x 3 mm). The detection limits for felodipine was 0.25 ng.ml-1. The precisions (RSD%, n = 5) of within-day and day-to-day were less than 5.09% and 8.62%, respectively. The pharmacokinetic parameters of felodipine in ten men were investigated by this method. The concentration-time curve was fitted to a two-compartment model. Its main pharmacokinetic parameters were: T1/2 alpha = 0.76 h, T1/2 beta = 16.09 h, Cmax = 4.78 ng.ml-1, Tmax = 2.01 h, AUC = 45.2 h.ng.ml-1.

Pathogen transmission in child care settings studied by using a cauliflower virus DNA as a surrogate marker

Two regions of cauliflower mosaic virus DNA were designed as markers to study pathogen transmission in a child care home (CCH) and child care center (CCC) and in homes of CCC children. The DNA markers were stable for 1 month in the environment. The DNA markers were introduced into the environment through sensitized objects, and spread in the environment was traced by detection of the markers with polymerase chain reaction. The DNA markers spread rapidly in both the CCH and CCC after introduction and spread more rapidly in the toddler room than in the infant room of the CCC. Hand touching of contaminated areas was the major factor leading to spread of the markers. Hand washing and surface wiping decreased spread of the markers. The markers spread minimally from room to room in the CCC but were detected in the children's homes after introduction of markers in the CCC.

Left-ventricle boundary detection from nuclear medicine images

We present here a new algorithm for segmentation of nuclear medicine images to detect the left-ventricle (LV) boundary. In this article, other image segmentation techniques, such as edge detection and region growing, are also compared and evaluated. In the edge detection approach, we explored the relationship between the LV boundary characteristics in nuclear medicine images and their radial orientations: we observed that no single brightness function (eg, maximum of first or second derivative) is sufficient to identify the boundary in every direction. In the region growing approach, several criteria, including intensity change, gradient magnitude change, gradient direction change, and running mean differences, were tested. We found that none of these criteria alone was sufficient to successfully detect the LV boundary. Then we proposed a simple but successful region growing method--Contour-Modified Region Growing (CMRG). CMRG is an easy-to-use, robust, and rapid image segmentation procedure. Based on our experiments, this method seems to perform quite well in comparison to other automated methods that we have tested because of its ability to handle the problems of both low signal-to-noise ratios (SNR) as well as low image contrast without any assumptions about the shape of the left ventricle.

Alveolar bone loss one year following ovariectomy in sheep

There is little information concerning the incidence of alveolar bone loss in estrogen-deficient women. Ovariectomized sheep are valid models for study of the effects of estrogen deficiency on bone metabolism. The objective of this study was to compare alveolar bone loss in control (C) and ovariectomized sheep (OVX) at 3 and 12 months following surgery. OVX animals had decreased serum levels of 17-beta-estradiol and increased serum levels of osteocalcin, IL-6, and urinary levels of deoxypyridinoline which, taken together, suggest development of osteoporosis. The mean probing depths and percentage of sites with pocket depths 4 to 6 mm and > 6 mm were significantly greater in OVX than C at each time period and in OVX were significantly greater at 12 months that at 3 months. Gingival tissue interleukin-6 (IL-6) levels (but not the number of IL-6(+) cells) were elevated adjacent to deep periodontal pockets; however, there was no significant elevation of levels of the proinflammatory cytokines IL-1 beta and IL-8 within gingiva. Taken together, the data suggest a systemic contribution for progression of periodontal disease associated with estrogen deficiency. This may involve upregulation of systemic IL-6 synthesis and transfer to gingiva in serum, resulting in enhanced IL-6 accumulation within the gingival tissues or reduced bone density allowing for a greater amount of alveolar bone loss.

High accuracy, wide range, rotation angle measurement by the use of two parallel interference patterns

Based on the idea of measuring small rotation angles with a parallel interference pattern (PIP), a method is developed to measure large rotation angles accurately. Two parallel PIP's that have different periods are used to measure a rotation angle of an object. The measurement made with a small-period PIP provides a high accuracy, and the measurement made with a large-period PIP provides a wide range. An accurate measurement for wide-range angles is made by combining the two measured values. The accuracy of the phase detection is determined by the periods of two PIP's. Rotation angles from approximately -30 to 30 arc min can be measured with an accuracy of 0.2 arc sec. Analytical results are supported by experimental results.

Supercoil-induced extrusion of a regulatory DNA hairpin

Bacteriophage N4 virion RNA polymerase (N4 vRNAP) promoters contain inverted repeats, which form a 5- to 7-base-pair stem, 3-base loop hairpin that is required for vRNAP recognition. We show that, contrary to certain theoretical predictions, hairpin extrusion can occur at physiological superhelical densities in a Mg2+-dependent manner. Specific sequences on the template strand are required for hairpin extrusion. These sequences define stable DNA hairpins that are relatively unreactive to single strand-specific probes. In addition, a specific stable hairpin-inducing sequence can regulate transcription in vivo. Thus, a DNA structure, in its natural environment, is involved in transcriptional regulation.

Manifestation of Behcet's disease in the digestive tract

OBJECTIVE

To study the manifestations of Behcet's disease (BD) in the digestive tract and its differential diagnosis from common inflammatory bowel diseases.

METHODS

The symptoms and endoscopic, X-ray's or surgical characteristics of 24 cases of Behcet's disease with digestive tract manifestations were analysed.

RESULTS

The lesions mainly occurred in tileocecum, and frequently led to hemorrhage that required surgery. The recurrent rate was as high as 77.7%.

CONCLUSION

Importance should be attached to early diagnosis of BD of the digestive tract to prevent serious complications.

Clinical significance of serum 7S collagen and type VI collagen levels for the diagnosis of hepatic fibrosis

OBJECTIVE

To measure serum 7S collagen (7S-C) and type VI collagen (VI-C) levels by radioimmunoassay (RIA) in Chinese patients with various liver disorders and in CCl4-treated SD rats, and to investigate the significance of the elevated levels of serum 7S-C and VI-C.

METHODS

Serum 7S-C and VI-C levels were measured in 40 healthy control subjects, 168 patients with various liver disorders and non-hepatic diseases, and 52 CCl4-treated SD rats by using RIA which was developed in our hospital.

RESULTS

Serum 7S-C and VI-C were significantly elevated in patients with chronic active hepatitis (CAH), liver cirrhosis (LC), hepatic cellular carcinoma (HCC) (P < 0.01 respectively), chronic persistent hepatitis (CPH), and some with non-hepatic diseases (P < 0.05). Serum 7S-C, serum laminin and hyaluronic acid were well correlated. Serum 7S-C and VI-C were not closely correlated. Both collagens were correlated with serum albumin/globulin ratio, aminotransferase and total bilirubin, not with alkaline phosphatase. In CCl4-treated SD rats, serum 7S collagen and type VI collagen levels were correlated with the degree of hepatic fibrosis.

CONCLUSIONS

Serum 7S collagen and type VI collagen are useful markers for diagnosing liver fibrosis. And the combined measurement of IV-C, VI-C and other markers of connective tissue metabolism or biochemical data seems to provide additional information to predict progressive hepatic fibrosis.

Expression of the spinach betaine aldehyde dehydrogenase (BADH) gene in transgenic tobacco plants

Plasmid pLS9 contains a 1.5-kb of spinach cDNA including its complete open reading frame. The 1.5-kb BADH cDNA was cut from pLS9 using restriction enzyme and was inserted into the expression cassette of plasmid pYH between the CaMV 35S promoter and polyA signal sequence. The 35S-BADH cDNA-polyA fragment of pYH was cloned into a polylinker cloning site of the binary vector pBin19. The resulting plasmid pBinBADH-S was transferred to Agrobacterium tumefacies LBA4404. The tobacco plants were transformed with strain LBA4404 containing pBinBADH-S, and more than ninety kanamycin-resistant transformants were selected. Polymerase chain reaction (PCR) detection showed that more than 60% of the transformed tobacco plants contained the foreign BADH gene. The Western blot analysis, BADH enzymatic assay, specific stain for BADH activity, and the test for salt tolerance showed that BADH gene was normally expressed in the transgenic tobacco plants. The BADH enzymes also presented in chloroplasts and cytosol of the transgenic plants. The transgenic tobacco plants having strong expression of BADH gene had strong ability to tolerate high salt stress.

[Effect of xiaopiling granules on the treatment of gastric precancerous changes as detected by image analyzer and electronic microscope]

Therapeutic effect of Xiaopiling Granules on gastric precancerous changes was observed, using image analyzer and electronic microscope. The result indicated that the Granules could efficiently eliminate gastric mucositis, nourish gastric mucosa, soften or restrain dysplasia, ameliorate structure atypism and cell atypism of dysplasia, promote elimination of dysplasia and efficiently ameliorate the ultrastructure of gastric precancerous changes.

Measurement of two-dimensional small rotation angles by using orthogonal parallel interference patterns

Based on measuring one-dimensional small rotation angles by using a parallel interference pattern (PIP), a method for measuring two-dimensional (2D) small rotation angles by using two different PIP's that are orthogonal to each other is proposed. We simultaneously measure the 2D small rotation angles Δθ and Δφ by detecting the phases of the orthogonal PIP's reflected by an object at two detection points. A sensitivity of 4.9 mrad/arcsec and a spatial resolution of 1.5 × 1.5 mm(2) are achieved in the measurement. Theoretical analysis and experimental results show that error ε(1) in the measurement of Δφ is almost equal to -0.01Δθ and error ε(2) in the measurement of Δθ is almost equal to -0.01Δφ. For small rotation angles of less than a few tens of arcseconds, the random errors whose standard deviations are 0.6 arcsec are dominant.

Conformational flexibility and crystallization of tandemly linked type III modules of human fibronectin

Fibronectin is a large cell adhesion molecule that is composed of several functional domains. The cell-binding domain that binds to cell surface integrins consists of repeated homologous type III modules. In this study, recombinant fragments from the cell-binding domain of human fibronectin that participate in a newly characterized fibronectin-fibronectin interaction with FNIII1 were crystallized. In each case, the crystals had more than one fibronectin fragment in the asymmetric unit. Crystals of FNIII10-11 grew in the space group C2 with a = 117.1 A, b = 38.6 A, c = 80.6 A, beta = 97.2 degrees, and two molecules in the asymmetric unit. These crystals diffracted to 2.5 A resolution. Fragment FNIII8-11 and a shorter fragment, FNIII8-10, crystallized in hexagonal space groups with large unit cells and two to four molecules per asymmetric unit. Even very large crystals of these fragments did not diffract beyond 4 A. The crystal packing for this collection of fibronectin fragments suggests conformational flexibility between linked type III modules. The functional relevance of this flexibility for elongated versus compact models of the cell-binding domain of fibronectin is discussed.

[Expression of CDKN2 gene product in human bronchogenic carcinoma]

OBJECTIVE

To examine the expression of P16 protein in bronchogenic carcinoma and normal tissue adjacent to carcinoma and to determine the relationship between the gene and bronchogenic carcinoma.

METHOD

Using a rabbit polyclonal antibody against P16 (N-20), the expression of P16 protein was studied immunohistochemically on formalin fixed, paraffin embedded sections.

RESULTS

The cytoplasmic P16 protein was mainly present in normal bronchial epithelium (93.8%), serous gland (92.6%) and alveolar epithelium (71.4%), the expression levels of P16 were significantly lower in carcinoma tissues (61.9%) when compared to levels in their normal counterparts (P < 0.01). Among tumors, squamous cell carcinomas and small cell carcinomas exhibited lower P16 expression levels compared with adenocarcinomas (P < 0.01). The expression levels of P16 were lower in poorly-differentiated adenocarcinomas compared with those in well-differentiated adenocarcinomas (P < 0.05).

CONCLUSIONS

The results suggested that CDKN2 gene was a tumor suppressor gene, the inactivation of which were involved in the carcinogenesis of bronchogenic carcinoma and implicated in tumor differentiation.

Analysis of the N-glycosylation of the serum glycoproteins defined by Con A, PHA-E, RCA1 and WGA in Chinese patients with gastrointestinal diseases

Glycoproteins from tumor cells isolated by Con A, PHA-E and RCA1, were coupled to horse radish peroxidase and then used as reporters to evaluate the oligosaccharides change on serum glycoproteins in digestive tract diseases and individual healthy persons. A value 2 standard deviation above the mean of the healthy person group was considered positive. The results indicated that the positive rates of the oligosaccharides bound with Con A, PHA-E and RCA1 were 51% (61/119), 70.6% (84/119), and 76.4% (91/119) in patients with gastric cancer; 53.3% (16/30), 46.7% (14/30) and 66.7% (20/30) in esophageal cancers; 28.5% (15/49), 49.0% (24/49) and 46.9% (23/49) in colorectal cancer; 78.1% (25/32), 81.3% (26/32) and 31.3% (10/32) in gallbladder tumors; 60.4% (29/48), 54.1% (26/48) and 39.5% (19/48) in hepatocellular cancer. The positive rates among the patients with benign diseases were also found to be 12.7% (16/126), 15.5% (20/126) and 26.2% (33/126). However, the expression of the oligosaccharide moieties recognized by WGA on the glycoprotein bound with Con A, was significantly lower in the serum of patients with tumors than in those with benign disease and in healthy individuals (P < 0.01, P < 0.01).

E. coli SSB activates N4 virion RNA polymerase promoters by stabilizing a DNA hairpin required for promoter recognition

Bacteriophage N4 virion RNA polymerase transcription of double-stranded promoter-containing DNAs requires supercoiled template and E. coli single-stranded DNA-binding protein (EcoSSB); other single-stranded DNA-binding proteins cannot substitute. The DNA determinants of virion RNA polymerase binding at the promoter comprise a small template-strand hairpin. The requirement for EcoSSB is surprising, since single-stranded DNA-binding proteins destabilize hairpin structures. DNA footprinting of EcoSSB on wild-type and mutant promoters indicates that EcoSSB stabilizes the template-strand hairpin owing to the hairpin-loop sequences. Other single-stranded DNA-binding proteins destabilize the promoter hairpin, explaining the specificity of EcoSSB activation. We conclude that EcoSSB activates transcription by providing the appropriate DNA structure for polymerase binding. The existence of small hairpins stable to single-stranded protein binding suggests a novel mechanism that provides structural determinants for specific recognition in single-stranded DNA transactions by an otherwise nonspecific DNA-binding protein.

[Expression of oncogene and anti-oncogene in mouse lung cancer induced by coal-burning smoke]

Previous epidemiology studies have shown association between coal burning and human lung cancer. To confirm relationship of coal burning to lung cancer formation and progression the expression of p53 and c-myc in 13 mouse lung cancer induced by coal-burning smoke and 5 mouse lung tissue control was studied by DNA-RNA in situ hybridization (ISH). Nine of 13 specimens showed c-myc overexpression but it occurred only 1 in 9 in the adjacent tissue. There was overexpression of p53 mRNA in all 13 lung cancer and 5 adjacent tissues. None in the controls was expression of p53 and c-myc detected. When compared to controls, there was significant higher expression of c-myc gene (P = 0.002) and p53 gene (P = 0.0001). The results confirm that overexpression of p53 and c-myc are common molecular events of lung cancer by coal-burning smoke and provide further evidence that smoke from coal burning is a causative agent of lung cancer.

Intracellular calcium reaches different levels of elevation in hyperactivated and acrosome-reacted hamster sperm

Calcium plays a role in sperm motility hyperactivation and the acrosome reaction, but the relationship between cytoplasmic calcium (Ca2+in) levels in the two states was heretofore unknown. The Ca2+ indicator indo-1 was used to detect Ca2+in in moving hamster sperm in two sets of experiments. In the first experiment, activated, hyperactivated, and zona pellucida-induced acrosome-reacted/hyperactivated sperm were analyzed at the time of peak of activity for each state. In the second experiment, sperm in all states were analyzed at one time point. In both sets, mean Ca2+in in the acrosomal region, postacrosomal region, and flagellar midpiece was greater in hyperactivated sperm than in activated sperm, and in acrosome-reacted/hyperactivated sperm than in unreacted/hyperactivated sperm (P < 0.001). Ca2+in had increased to a greater extent in the midpiece than in the head in hyperactivated sperm, while the reverse was true for acrosome-reacted sperm. Oscillations at the frequency of the flagellar beat cycle were detected chiefly in the proximal flagellar midpiece of acrosome-reacted sperm, as they had been previously reported to occur in activated and hyperactivated sperm. Thus, Ca2+in may be maintained at two different elevated levels in sperm, and continues to oscillate after the acrosome reaction.

Development of an ELISA to detect MX virus, a human calicivirus in the snow Mountain agent genogroup

MX virus is a Snow Mountain agent (SMA) genogroup human calicivirus (HuCV) identified in a Mexican child with diarrhoea. An ELISA using hyperimmune antisera to the recombinant MX virus (rMX) capsid was developed to detect SMA genogroup HuCVs in stool specimens. The rMX ELISA detected the prototype MX virus, SMA, and Hawaii agent (HA), but not Norwalk virus (NV) or Sapporo virus. Twenty-three diarrhoea stool specimens from children attending day care centres in Norfolk, Virginia, were positive by the rMX ELISA and results were confirmed by reverse transcription-polymerase chain reaction (RT-PCR). Eight of 20 diarrhoea stool specimens from children in the United Kingdom previously shown to contain small round structured viruses (SRSVs) or HuCVs by electron microscopy were also positive by the rMX ELISA and RT-PCR. Sequence analysis of the RT-PCR products showed that all the rMX ELISA-positive viruses belong to the SMA genogroup. These data also showed that the SMA genogroup can be further divided into two subgroups: subgroup 1 includes prototypes SMA and HA, and subgroup 2 includes MX virus, minireovirus, Oth-25 and Bristol virus.

[T antigen test of sputum--a new simple method for the screening of lung cancer]

The sputum specimens from 116 healthy persons and 216 cases of benign and malignant lung diseases were detected for T antigen using a strip test by enzyme galactose oxidase-Schiff sequence. The result shows that 165 cases of the 182 patients with lung cancer, confirmed by cytology and histology, had positive results, whereas 22/116 (19.0%) of healthy controls were positive. So the sensitivity was 90.7% and the specificity was 81.0%. In 28 cases of patients whose cytology of sputa showed various degrees of dysplasia, 21 were found T antigen positive, of which 15 patients were identified to be lung cancer in the follow-up study. In addition, three cases of early lung cancer in this study were also positive, suggesting that T antigen was expressed at an earlier stage in the malignant process. The study has indicated that T antigen test of sputum is a sensitive method for the diagnosis of lung cancer. It may also be a promising approach for the massive screening of lung cancer in terms of its rapidity, economy and simplicity.

Measurement of small rotation angles by using a parallel interference pattern

We propose a method for measuring rotation angles by using a parallel interference pattern. At two points on a parallel interference pattern reflected by an object, we detect phase changes in the reflected parallel interference pattern caused by rotations of the object. A high sensitivity, or a high ratio of the phase change to the rotation angle, 17 mrad/arcsec, can be achieved by determining the positions of two detection points. A high spatial resolution of ~0.5 mm is also obtained. We analyze the measurement error caused by the alignment of the parallel interference pattern and a random measurement error caused by the phase detection. The theoretical analyses and the experimental results make the characteristics of the method clear and show that the method has an accuracy of 0.2 arcsec for small rotation angles.

[Effects of three kinds of decoction on histopathology of gastric mucosa, gastric pH and the content of bile acid in experimental chronic gastritis in rats]

Experimental chronic gastritis (ECG) models were established in rats by inserting a spring into pyloric canal as well as feeding sodium deoxycholate. An experiment was undertaken to observe the therapeutic effects of three formulas of traditional Chinese medicine "Shipitong", "Ganpingyangwei" and "Weile". The experimental results show that all of the three decoctions can reduce gastric pH and bile acid of the ECG rats and make gastric mucosal histomorphology of these rats change markedly.

[Effects of 3 kinds of decoction on serum gastrin, gastrin cell density and the content of PGE2 of gastric antral mucosa in experimental chronic gastritis in rats]

Experimental chronic gastritis (ECG) models were established in rats by inserting a spring into pyloric canal as well as feeding sodium deoxycholate. An experiment was undertaken to observe the therapeutic effects of three formulas of traditional Chinese medicine "Shipitong" (SPT), "Ganpingyangwei" (GPYW) and "Weile" (WL). The experimental results show that all of the three decoctions can make serum gastrin, gastrin cell density and amount of antral mucosal PGE2 of the ECG rats return to normal levels.

Field potential mapping of neurons in the lumbar spinal cord activated following stimulation of the mesencephalic locomotor region

The spinal neurons involved in the control of locomotion in mammals have not been identified, and a major step that is necessary for this purpose is to determine where these cells are likely to be located. The principal objective of this study was to localize lumbar spinal interneurons activated by stimulation of the mesencephalic locomotor region (MLR) of the cat. For this purpose, extracellular recordings of MLR-evoked cord dorsum and intraspinal field potentials were obtained from the lumbosacral enlargement during fictive locomotion in the precollicular-postmammillary decerebrate cat preparation. Potentials recorded from the dorsal surface of the cord between the third lumbar (L3) and first sacral (S1) segments typically showed four short-latency positive waves (P1-P4). These P-waves were largest between the L4-L6 segments. The amplitude of the P2-4 waves increased with the appearance of locomotion and displayed rhythmic modulation during the locomotor step cycle. Microelectrode recordings from the L4-L7 spinal segments during fictive locomotion revealed the presence of both positive and negative short-latency MLR-evoked intraspinal field potentials, and were used to construct isopotential maps of the evoked potentials. Positive field potentials were observed throughout the dorsal horn of the L4-L7 spinal segments with the largest amplitude potentials occurring in laminae III-VI. Negative field potentials were found in laminae VI-X of the lumbar cord. The shortest latency negative field potentials were observed in lamina VII and at the border between laminae VI and VII and were considered to be evoked monosynaptically from the arrival of the descending volley. Short-latency mono- and disynaptic negative field potentials were also observed in lamina VIII. Longer latency, tri- and polysynaptic field potentials were observed in laminae VII and VIII. Many of the longer latency negative waves observed in laminae VII and VIII followed shorter latency negative potentials recorded from the same location. Laminae VII and VIII negative field potentials were largest in the L5-6 and L4-5 spinal segments, respectively. Negative field potentials were also evoked in the motor nuclei of the L4-7 spinal segments. The segmental latencies for these potentials indicate that they were evoked di- and trisynaptically.(ABSTRACT TRUNCATED AT 400 WORDS)

Cleavage of an amide bond by a ribozyme

A variant form of a group I ribozyme, optimized by in vitro evolution for its ability to catalyze magnesium-dependent phosphoester transfer reactions involving DNA substrates, also catalyzes the cleavage of an unactivated alkyl amide when that linkage is presented in the context of an oligodeoxynucleotide analog. Substrates containing an amide bond that joins either two DNA oligos, or a DNA oligo and a short peptide, are cleaved in a magnesium-dependent fashion to generate the expected products. The first-order rate constant, kcat, is 0.1 x 10(-5) min-1 to 1 x 10(-5) min-1 for the DNA-flanked substrates, which corresponds to a rate acceleration of more than 10(3) as compared with the uncatalyzed reaction.

[Effect of xiaopiling granules on muscular histochemistry of gastric precancerous changes in rats]

The effect of Xiaopiling Granules on muscular histochemistry of gastric precancerous changes in rats was observed quantitatively. The activity of SDH and M-ATPase as well as the content of muscular glycogen in model groups were found significantly lower than those of the normal groups (p < 0.01), and in this decrease Xiaopiling Granules had markedly played a preventive and therapeutic role.

The lipids of slugs and snails: evolution, diet and biosynthesis

There is a considerable gap in current knowledge of the lipid composition of snails and slugs, both of which belong to the phylum Mollusca. We have therefore analyzed the sterol and fatty acid compositions of three species of slugs and three species of snails. The sterols of slugs included eight different sterols: cholesterol contributed 76-85% of the total sterols, brassicasterol accounted for 4-13%; other sterols we identified were lathosterol, 24-methylene cholesterol, campesterol, stigmasterol, sitosterol and sitostanol. In contrast, snails contained two additional sterols, desmosterol and cholestanol. Of the polyunsaturated fatty acids in slugs, linoleic (18:2n-6) and arachidonic acids (20:4n-6) were the major n-6 fatty acids, while linoleic (18:3n-3) and eicosapentaenoic acids (20:5n-3) were the predominant n-3 fatty acids. Docosahexaenoic acid (22:6n-3), the end product in the n-3 fatty acid synthetic pathway and an important membrane fatty acid of mammals, fish and birds, was absent in both slugs and snails. However, the analogous product of n-6 fatty acid synthesis, 22:5n-6, was found in both snails and slugs. This raises speculation about preference for n-6 fatty acid synthesis in these species. Our data show the unique sterol and fatty acid compositions of slugs and snails, as well as similarities and differences in sterol composition between the two. The results between the two land mollusks are contrasted with those of marine mollusks, such as oysters, clams and scallops.

Experimental study of a bow-tie-shaped optical fiber ring resonator with two 2 × 2 fiber couplers

An experimental study of a bow-tie-shaped double-coupler fiber ring resonator is presented. Multiple resonances of the transmitted output intensity and the splitting of the main resonance dip or peak have been observed. The experimental results are discussed and compared with theoretical results. The observed output property suggests the possible applications of the resonator as periodic Butterworth-like, narrow-band passing, and blocking filters.

Initial characterization of an antineoplastic, polysaccharide-rich extract of Mycobacterium bovis BCG, Tice substrain

A purified hot-water extract from Mycobacterium bovis (BCG vaccine) has been found to have significant antitumor activity against a murine sarcoma in vivo, but not in vitro, suggesting that the active compound is behaving as an immunostimulant. The material, termed PS1, has an average molecular weight of 22.4 kDa, is freely soluble in water, but has low solubility in acetone or ethanol, and is remarkably heat-stable, as is the parent BCG vaccine in terms of high-dose antitumor activity. PS1 contains at least 50% carbohydrate, consisting mainly of glucose, galactose and mannose, and about 10% lipid that may correspond to phosphatidylinositol. It shares chemical and biological properties with an arabinomannan isolated from M. tuberculosis, but it contains only trace quantities of lipoarabinomannan (LAM). Crossed immunoelectrophoresis indicated that PS1 contains the mycobacterial antigen 89, but only a single, non-migrating precipitin arc appeared on immunoelectrophoresis against a standard anti-BCG serum. PS1 appears to be non-toxic in mice up to a dose of 5 mg/kg, while as little as 70 micrograms/kg is sufficient to inhibit tumor formation significantly.

Optical-fiber double-loop resonator with a nonplanar 3 × 3 fiber coupler

We present for the first time to our knowledge a new and simple single-mode optical-fiber double-loop resonator. The double-loop resonator consists of two fiber loops constructed from a nonplanar 3 × 3 directional fiber coupler and two fiber delay lines. When the lengths of the fiber loops are different, additional periodic-resonance notches appear. The depths and the positions of these notches depend on the difference between the phase changes, and the coupling of the two fiber loops. This double-loop resonator can be used as a spectral filter and a sensor.

Intracellular calcium increases with hyperactivation in intact, moving hamster sperm and oscillates with the flagellar beat cycle

At some time before fertilization, mammalian sperm undergo a change in movement pattern, termed hyperactivation. There is evidence that hyperactivation offers an advantage to sperm for detaching from the oviductal mucosa, for penetrating viscoelastic substances in the oviduct, and for penetrating the zona pellucida. Hyperactivation is known to require extracellular calcium, but little else is known about the mechanisms by which calcium affects sperm movement. The calcium-sensitive fluorescent dye indo-1 was used to follow intracellular calcium levels ([Ca2+]i) in individual moving sperm. Sperm were loaded with 10 microM of the acetoxymethyl ester form of the dye and then rinsed. The dye was excited at 340 nm by using a filtered xenon stroboscope, and images at the 405-nm and 490-nm excitation maxima were simultaneously digitized at 30 per sec for 2.1 sec. [Ca2+]i was significantly higher in the acrosomal and postacrosomal regions of the head and in the flagellar midpiece (the principal piece could not be measured) in hyperactivated than in nonhyperactivated sperm (P < 0.0001). [Ca2+]i oscillations were detected in the proximal half of the midpiece that were identical in frequency to the flagellar-beat-cycle frequency in 12 of 17 hyperactivated sperm (median, 3.5 Hz). Rapid [Ca2+]i oscillations were also detected in the acrosomal and postacrosomal regions, as well as in the distal midpiece. Oscillations were not eliminated by dampening the flagellar bending with methyl cellulose. The [Ca2+]i oscillations detected in sperm are significantly more rapid than oscillations detected in other cell types.

The effects of intrathecal administration of excitatory amino acid agonists and antagonists on the initiation of locomotion in the adult cat

Development of pharmacological strategies for the control of locomotion in patients with spinal cord injury or disease requires an understanding of the neuroactive substances involved in the activation of the spinal cord neural systems for the control of locomotion. Studies using the in vitro preparations of the lamprey, frog embryo, and newborn rat indicate that excitatory amino acids (EAAs) are involved in the initiation of locomotion. The present study determines whether spinal EAA receptors play a role in locomotion in an in vivo, adult mammalian preparation. Experiments were performed on precollicular, postmammillary decerebrate cats, some of which were spinalized at the 13th thoracic segment. Cannulas for drug infusions were positioned intrathecally in the lumbar region of the spinal cord. A ligature around the spinal cord at the level of the 13th thoracic segment prevented rostral diffusion of the drugs. Locomotion was monitored with electromyograms in treadmill locomotion experiments and electroneurograms in fictive locomotion experiments. Intrathecal infusion of either the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid or the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione blocked hindlimb treadmill and fictive locomotion induced by electrical stimulation of the mesencephalic locomotor region (MLR) of the midbrain. Intrathecal administration of NMDA elicited hindlimb fictive locomotion in resting animals similar to that evoked by electrical stimulation of the MLR. At lower concentrations, NMDA evoked either independent bursting activity in the various nerves or loosely organized rhythmicity showing little reciprocity between antagonists. In contrast, administration of the EAA uptake blocker dihydrokainic acid (DHK) evoked intermittent periods of bursting activity characterized by a variable duration and a high degree of reciprocity between flexors and extensors. Given together at low concentrations, NMDA and DHK produced a well-coordinated locomotor pattern. Kainate and quisqualate were ineffective in producing fictive locomotion. These results are consistent with the suggestion that EAAs play a role in the initiation of mammalian locomotion. Furthermore, the results are consistent with those obtained from the neonatal rat in vitro preparations.

Life security of the elderly: rural population control

"This article will examine the life security among the elderly in rural China and its impact on the population control in those areas." Data are from a fertility survey conducted in five rural villages in 1990.

[Effects of 3 Chinese medical prescriptions on alkaline reflux gastritis in rats]

The experimental alkaline reflux gastritis in rats was established after 9 weeks of anastomosis between stomach and jejunum. The experiment shows that xiangsha liujunzi decoction, xiaochaihu decoction and dahuang gancao decoction all help to inhibit edema, hyperamia and extravasted blood, as well as depress inflammatory infiltration and hyperplasia. The number of intestinal metaplasia in the group treated with xiangsha liujunzi decoction is decreased. All the three prescriptions are not able to lower the contents of bile acid in the stomach.

[Regulation of purine biosynthesis. I. Isolation of add:: MudJ (lacZ, Kanr) insertions and genetic mapping]

Report here is the isolation of adenosine deaminase deficient mutants and genetic mapping. Engineering transposon MudJ (lacZ, Kanr) was used for mutagenesis and six add:: MudJ were obtained among 20,000 Kanr transductants. Adenosine deaminase activity of these mutants were assayed and all are negative. Cotransduction analysis of add::MudJ indicated that add is 70% linked to pmi(31') and 37% linked to zxx1900::Tn10d-tet insertion which is 10% linked to purR(30'). Three points cross showed that add is located between pmi and Tn10d-tet insertion. Therefore the gene order is purR-zxx1900::Tn10d-tet-add-pmi.

Hyperactivation enhances mouse sperm capacity for penetrating viscoelastic media

A movement pattern known as hyperactivation has been observed among sperm recovered from the periovulatory oviduct of several species. In culture medium, hyperactivated sperm swim in a pattern that is far less progressive than that of freshly ejaculated sperm. In the oviduct, sperm encounter highly viscoelastic substances, such as mucus and the cumulus matrix. We have previously reported that hyperactivated hamster sperm become more progressive in vitro when the viscosity of medium is increased. In the present study, we tested the effect of increasing the viscosity and viscoelasticity of the medium on the swimming progressiveness of mouse sperm. Caudal epididymal sperm were incubated in a medium that produced hyperactivated motility in 60 min. Swimming velocities of sperm incubated for 60 min were compared with those of fresh sperm after addition of one of the following to culture medium: solutions of 1.8% methylcellulose (high viscosity), 1.8% long chain polyacrylamide (high viscoelasticity), or culture medium alone (low viscosity). In culture medium, hyperactivated sperm had significantly lower mean straight-line velocities than fresh sperm (p = 0.004); this difference disappeared in methylcellulose (p = 0.085) and was reversed in polyacrylamide (p = 0.004). This and other velocity measurements indicated that hyperactivated mouse sperm penetrate viscoelastic media more efficiently than fresh sperm and therefore may be more efficient at penetrating oviductal mucus and cumulus matrix in vivo.

[Effect of sodium valproate on bicuculline-induced epileptiform activity in rat hippocampal slices in vitro]

Experiments were conducted on the rat hippocampal slices in vitro with the superfusion of bicuculline (Bcl, 10 mumol/L) and stimulation of Schaffer collaterals by single pulse to produce epileptiform activity of the pyramidal cells in CA1 area. In these experiments the effect of constant microinjection of sodium valproate onto the surface of slice on the epileptiform activity was studied. The results showed that the valproate, in concentration of 20, 30, 50 and 100 mmol/L, inhibited the Bcl-induced epileptiform activity in a manner of dose-dependence. It was deduced that the inhibition of epileptiform activity by the valproate is possibly related to the recovery of and increase in the inhibition mediated by GABAergic neurons and may be also to the non-synaptic mechanism of the valproate in rat hippocampus.

Differential theophylline inhibition of alkaline phosphatase and 5'-nucleotidase of bovine milk fat globule membranes

1. The effects of theophylline (1,3-dimethylxanthine) on alkaline phosphatase and 5'-nucleotidase activities of bovine milk fat globule membranes (MFGM) were examined. 2. Theophylline inhibited MFGM alkaline phosphatase in a concentration-dependent manner with 50% inhibition produced by 99 +/- 28 microM theophylline. 3. The 5'-nucleotidase activity was resistant to theophylline inhibition with 50% inhibition produced by 33.9 +/- 3.1 mM theophylline. 4. Theophylline was an uncompetitive inhibitor of MFGM alkaline phosphatase with a Ki of 126 +/- 15 microM. 5. The extent of theophylline inhibition of alkaline phosphatase activity was independent of the substrate utilized in the assay. 6. The effect of theophylline on bovine MFGM alkaline phosphatase was similar to theophylline effects on other mammalian alkaline phosphatases of liver/bone isoenzyme origin.