[Atraumatic restorative treatment fillings and fissure sealants in permanent teeth--a 2-year study]

OBJECTIVE

To study the feasibility of providing Atraumatic Restorative Treatment (ART) in schools and in rural areas in China, and to evaluate the acceptance and effectiveness of the treatment.

METHODS

The study was conducted among 272 grade one students chosen from four different secondary schools in Deyang of Sichuan Province, China. The mean age of the subjects was 12.5 years. 107 boys and 165 girls were found at the baseline examination to have teeth that were suitable for receiving ART fillings or sealants. The treatments were performed within a month using the glass ionomer Ketac-Molar manufactured by ESPE. Evaluation was carried out at 3 months, one year and two years after treatment.

RESULTS

ART fillings were placed in 295 permanent teeth, and the 1-year and 2-year success rates were 95.7% and 91.1% respectively. ART sealants were placed in another 191 permanent teeth, and the 3-month, 1-year and 2-year success rates were 95.2%, 89.1% and 78.8% respectively. The incidence of recurrent caries was very low after two years, which were 2.1% and 0.6% for the fillings and sealants respectively. ART was accepted by the majority of the students.

CONCLUSION

ART is a simple, acceptable technique, and is suitable for widespread adoption in China.

[A randomized controlled clinical study of sparfloxacin versus ofloxacin in the treatment of bacterial infections]

OBJECTIVE

To evaluate the efficacy and safety of sparfloxacin in the treatment of bacterial infections.

METHODS

A randomized controlled multi-centre clinical trial was conducted. Ofloxacin used as the control drug. A total of 212 patients entered the study, with 106 in the sparfloxacin group and the remaining 106 in the ofloxacin group. Both compounds were given by oral administration.

RESULTS

The cure rate of sparfloxacin and ofloxacin was 74.5% and 69.8% respectively and the overall efficacy rate was 91.5% and 88.7% respectively. The bacterial clearance rate was 90.7% in the sparfloxacin group and 90.8% in the ofloxacin group. The adverse drug reaction rate of sparfloxacin and ofloxacin was 9.43% and 8.49% respectively. There was no statistical significant difference between the two groups for the above results. The results of in vitro activity of sparfloxacin as compared with other 5 antibacterial agents showed that sparfloxacin had good activity against many Gram-negative organisms and was similar to those of ofloxacin. The activity against Gram-positive organisms (MIC(90) <or= 0.25 mg/L) was generally higher than that of ofloxacin.

CONCLUSION

Sparfloxacin is a highly effective and safe broad-spectrum antibacterial agent for the treatment of bacterial infections. It is also effective in the treatment of infections caused by Gram-positive organisms.

[The origin of calcitonin gene-related peptide (CGRP) in burned skin of rats]

OBJECTIVE

To investigate the origin of calcitonin gene related-peptide (CGRP) in skin burn wound.

METHODS

Immunohistochemistry technique was used to determine change in distributive density in CGRP-containing nerve fibers in the wound, wound margin, remote intact skin of rats during the first 96 hours postburn.

RESULTS

It was shown that the distributive density of CGRP-containing nerve fibers in all areas decreased at 15 min postburn, but the density recovered earlier in wound margins compared to other sites. In addition, CGRP immunoreactive positive cells, which emigrated from blood vessel in dermis underneath the wound and wound margin, were related to CGRP-containing nerve fibers at 12 hours. Stronger staining intensity to CGRP was observed in those cells and they disintegrated and released CGRP immunoreactive materials into the dermis at 24 hours. Thereafter, those cells disappeared.

CONCLUSION

CGRP not only is released from cutaneous nerve, but also is synthesized and released by immune cells in response to burns.

A cluster of microvillous inclusion disease in the Navajo population

We report 4 unrelated patients with characteristic microscopic findings of microvillous inclusion disease (MID) with early-onset phenotype. All 4 patients came from the Navajo reservation in northern Arizona. A literature search revealed a fifth unrelated Navajo child with MID. The unusually high incidence in this population indicates that a founder effect might be responsible for an increased frequency of this rare genetic disorder in the Navajo. It is recommended that all Navajo infants presenting with severe diarrhea during early infancy undergo investigation for MID.

Flow cytometric analysis for enterotoxin exposed on Clostridium perfringens spores

Flow cytometric method (FCM) with fluorescent-labeled anti-CPE antibody was applied to develop a rapid, specific, and convenient method to detect enterotoxin (CPE) exposed on the surface of spores of Clostridium perfringens. The results obtained indicate that FCM can specifically detect CPE exposed on C. perfringens spores for a short time. Thus, FCM is found to be a rapid, specific, and convenient assay method for detection of CPE exposed on C. perfringens spores, suggesting that it will be hopefully useful to diagnose food poisoning caused by C. perfringens.

The caries-inhibiting effect of a fluoride drop program: a 3-year study on Chinese kindergarten children

OBJECTIVE

To evaluate the caries-inhibiting effect of a fluoride drops program in two kindergartens in Chengdu, Sichuan Province, a fluoride-deficient area.

METHODS

For 3 years, participating children ingested in school 0.25 mg fluoride daily, in the form of drops for 2 to 3-year-olds and 0.5 mg for children age 3 years and older. These systemic fluoride supplements were made available for over 180 days each year and they were distributed by teachers who maintained attendance records. Annual examinations were conducted for 176 2-year-olds who had used the supplements in the kindergartens and 148 control children. After 3 years, 128 test and 112 control children remained in the study.

RESULTS

The results demonstrated a marked reduction in dental caries in the control group: test children had 2.21 decayed, missing, or filled teeth (DMFT)-versus 4.32 in the control group, a reduction rate of 48.84%. The mean DMFT increments over the 3-year period were 1.76 and 3.92, respectively. Over a 1- to 3-year period of supplement use, the group provided with the fluoride drops had consistently lower caries prevalence than the control group. The differences were statistically significant.

CONCLUSIONS

This treatment regimen demonstrated an effective caries-inhibiting effect.

LMP-1, a LIM-domain protein, mediates BMP-6 effects on bone formation

Glucocorticoids can promote osteoblast differentiation from fetal calvarial cells and bone marrow stromal cells. We recently reported that glucocorticoid specifically induced bone morphogenetic protein-6 (BMP-6), a glycoprotein signaling molecule that is a multifunctional regulator of vertebrate development. In the present study, we used fetal rat secondary calvarial cultures to determine genes induced during early osteoblast differentiation as initiated by glucocorticoid treatment. Glucocorticoid, and subsequently BMP-6, was found to induce a novel rat intracellular protein, LIM mineralization protein-1 (LMP-1), that in turn resulted in synthesis of one or more soluble factors that could induce de novo bone formation. Blocking expression of LMP-1 using antisense oligonucleotide prevented osteoblast differentiation in vitro. Overexpression of LMP-1 using a mammalian expression vector was sufficient to initiate de novo bone nodule formation in vitro and in sc implants in vivo. These data demonstrate that LMP-1 is an essential positive regulator of the osteoblast differentiation program as well as an important intermediate step in the BMP-6 signaling pathway.

Effects of MK-801 on vicarious trial-and-error and reversal of olfactory discrimination learning in weanling rats

The effects of dizocilpine maleate (MK-801) on vicarious trial-and-error (VTE), and on simultaneous olfactory discrimination learning and its reversal, were observed in weanling rats. The term VTE was used by Tolman (The determiners of behavior at a choice point. Psychol. Rev. 1938;46:318-336), who described it as conflict-like behavior at a choice-point in simultaneous discrimination learning. It takes the form of head movements from one stimulus to the other, and has recently been proposed by Amsel (Hippocampal function in the rat: cognitive mapping or vicarious trial-and-error? Hippocampus, 1993;3:251-256) as related to hippocampal, nonspatial function during this learning. Weanling male rats received systemic MK-801 either 30 min before the onset of olfactory discrimination training and its reversal, or only before its reversal. The MK-801-treated animals needed significantly more sessions to acquire the discrimination and showed significantly fewer VTEs in the acquisition phase of learning. Impaired reversal learning was shown only when MK-801 was administered during the reversal-learning phase, itself, and not when it was administered throughout both phases.

Identification of Lys-403 in the PI-SceI homing endonuclease as part of a symmetric catalytic center

Superposition of the PI-SceI and I-CreI homing endonuclease three-dimensional x-ray structures indicates general similarity between the I-CreI homodimer and the PI-SceI endonuclease domain. Saddle-shaped structures are present in each protein that are proposed to bind DNA. At the putative endonucleolytic active sites, the superposition reveals that two lysine (Lys-301 and Lys-403 in PI-SceI and Lys-98 and Lys-98' in I-CreI) and two aspartic acid residues (Asp-218 and Asp-326 in PI-SceI and Asp-20 and Asp-20' in I-CreI) are related by 2-fold symmetry. The critical role of Lys-301, Asp-218, and Asp-326 in the PI-SceI reaction pathway was reported previously. Here, we demonstrate the significance of the active-site symmetry by showing that alanine substitution at Lys-403 reduces cleavage activity by greater than 50-fold but has little effect on the DNA binding activity of the mutant enzyme. Substitution of Lys-403 with arginine, which maintains the positive charge, has only a modest effect on activity. Interestingly, even though the Lys-301 and Lys-403 residues display pseudosymmetry, PI-SceI mutant proteins with substitutions at these positions have different behaviors. The presence of similar basic and acidic residues in many LAGLIDADG homing endonucleases suggests that these enzymes use a common reaction mechanism to cleave double-stranded DNA.

Sciatic nerve blockade in infant, adolescent, and adult rats: a comparison of ropivacaine with bupivacaine

BACKGROUND

Ropivacaine is a newly introduced local anesthetic. No data are available regarding its safety, efficacy, or sensory-selectivity in children. The sciatic block duration and systemic toxicity of bupivacaine and ropivacaine were compared among infant, adolescent, and adult rats.

METHODS

Infant, adolescent, and adult rats received blocks with ropivacaine or bupivacaine. Nociceptive, proprioceptive, and motor blockade were assessed. Systemic effects (contralateral leg analgesia, seizures, respiratory distress, apnea) were quantified. Plasma local anesthetic concentrations were measured at terminal apnea.

RESULTS

Nerve blockade for a given absolute dose lasted longer in infants than in older rats for both drugs. Block duration from ropivacaine generally was the same as or slightly shorter than bupivacaine. There was no difference in sensory-selectivity between the drugs. Doses required to induce all systemic toxicity indices were inversely related to age (e.g., the lethal dose in 50% of animals [LD50] of ropivacaine in infants is 155 mg/kg; in adults it is 54 mg/kg). All indices of toxicity occurred at higher doses per kilogram for ropivacaine than bupivacaine, at all ages (e.g., the LD50 of bupivacaine in infants is 92 mg/kg; in adults it is 30 mg/kg). Plasma concentrations at terminal apnea were higher for ropivacaine than for bupivacaine at all ages, and were higher in infants than in older rats.

CONCLUSIONS

Ropivacaine resembles bupivacaine in its local anesthetic effects but has a greater margin of safety. For a given absolute dose, sciatic blockade in infant rats lasts longer than in adolescents or adults. Although the doses (in milligrams per kilogram) causing toxicity were much higher in infants than in adults, this probably does not correspond to a wider therapeutic index.

Common molecular pathways in skeletal morphogenesis and repair

The formation of bone is a continual process in vertebrate development, initiated during fetal development and persisting in adulthood in the form of remodeling and repair. The remarkable capacity of skeletal tissues to regenerate has led to the hypothesis that the molecular signaling pathways regulating skeletogenesis are shared during fetal development and adult wound healing. A number of key regulatory pathways that are required for endochondral ossification during fetal development are described, and their reintroduction in fracture repair demonstrated. Secreted proteins such as Sonic and Indian hedgehog exert their effect on pattern formation and chondrogenesis in the appendicular skeleton, partly through regulation of molecules such as bone morphogenic proteins (Bmps) and parathyroid hormone-related peptide (PTHrP). Once chondrocytes have matured and hypertrophied, they undergo apoptosis and are replaced by bone; the transcription factor Cbfal plays a critical role in this process of chondrocyte differentiation and ossification. Analyses of the expression patterns of these genes during fracture healing strongly suggest that they play equivalent roles in adult wound repair. Knowledge acquired through the study of fetal skeletogenesis will undoubtedly contribute to an understanding of fracture repair, and subsequently guide the development of biologically based therapeutic interventions.

Long-term efficacy of recombinant interferon alpha 2a in the treatment of chronic hepatitis C: a randomized prospective study comparing two dose schedules in Chinese patients

OBJECTIVE

To compare the long-term efficacy of a dose of 3 million units (MU) of r-IFN alpha 2a (IFN-alpha 2a) three times a week (t.i.w.) for 6 months with a starting dose 6 MU for 3 months and subsequent reduction to 3 MU t.i.w for further 3 months.

METHODS

Sixty-eight serological and histological chronic hepatitis C patients with elevated serum alanine aminotransferase (ALT) were enrolled and randomized into two groups. Sixty-three patients were completed with full course of treatment. Five patients were withdrawn from trial (2 due to personal reasons and 3 due to adverse drug reactions during treatment). Thirty patients received 6 MU IFN-alpha 2a t.i.w., 3 months followed by 3 MU t.i.w. for another 3 months (Group A). Thirty-three patients received 3 MU IFN-alpha 2a t.i.w. for 6 months (Group B).

RESULTS

The sex, age, baseline serum bilirubin, ALT and aspartate aminotransferase (AST) levels were matched in both groups. At the end of the 6th month, the complete and partial response rates in Group A were 60.0% and 16.7% respectively, and the clearance of serum HCV-RNA was 53.3%. In Group B, the complete and partial response rates were 72.7% and 6.1% respectively, and the clearance of HCV-RNA was 61.3%. The patients were followed up for 6, 12, and 18 months after stopping treatment. In Group A, the rates of complete normalization of ALT and clearance of serum HCV-RNA at 24 months were 50.0% and 60.0% respectively. In Group B, the rates of normalization of ALT and clearance of HCV-RNA at 24 months were 54.4% and 41.9% respectively. The efficacy between the two groups showed no statistically significant difference. The response rates of treatment were similar to those in the patients with HCV genotype 1b and 2a. Six patients (10.8% of the study population) developed neutralization antibodies to IFN-alpha 2a during treatment, and four of them were responded to the treatment. Adverse drug reactions (ADR), were common, but most of them were tolerable, and the incidence of ADR was in both groups, but the severity was higher in Group A.

CONCLUSIONS

IFN-alpha 2a is effective in the treatment of Chinese patients with chronic hepatitis C. The sustained response rates and adverse drug reactions among two dose schedule groups are similar.

Topical tamoxifen--a potential therapeutic regime in treating excessive dermal scarring?

Abnormal dermal scarring which affects a large number of people is aesthetically disfiguring and can be functionally disabling. Existing medical and surgical strategies to prevent or to treat scars are frequently disappointing and more effective therapies are needed. Tamoxifen, which has been used extensively in the treatment of breast cancer over the last 20 years has recently been shown to inhibit the proliferation of fibroblasts cultured from keloid biopsies. Successful treatment of retroperitoneal fibrosis and desmoid tumours with tamoxifen has also been reported. We have investigated the potential of tamoxifen as an inhibitor of wound contraction, using fibroblast-populated collagen lattices as an in vitro model. From these studies we postulate that tamoxifen may have potential clinical significance in the treatment of abnormal scarring. Normal adult human skin fibroblasts were embedded within type I collagen, then medium either with or without addition of tamoxifen was added to the collagen lattices. Lattice diameters were measured at intervals to assess the influence of tamoxifen on the lattice contraction. The reversibility of the inhibitory effect of tamoxifen on lattice contraction was investigated by 'washing out the tamoxifen' at different time-points. To visualise changes in the morphology of fibroblasts MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] was added to the lattices. Tamoxifen at 1 and 5 microM had no significant influence on lattice contraction but higher concentrations of 50 and 100 microM completely inhibited contraction. At intermediate concentrations from 10 to 20 microM the degree of lattice contraction was dose-dependent. The reversibility of the inhibition was both dose- and time-dependent. Both the inhibition of contraction and the reversibility of inhibition appeared to correlate with changes in fibroblast morphology. The dose- and time-dependent inhibition of contraction by fibroblasts suggests that tamoxifen could be investigated as a novel potential therapeutic agent in treating abnormal dermal scarring.

Inhibition of hGrb10 binding to the insulin receptor by functional domain-mediated oligomerization

hGrb10 is a newly identified Src homology 2 (SH2) and pleckstrin homology (PH) domain-containing protein that binds to autophosphorylated receptor tyrosine kinases, including the insulin and insulin-like growth factor receptors. To identify potential downstream proteins that interact with hGrb10, we screened a yeast two-hybrid cDNA library using the full-length hGrb10gamma as bait. A fragment of hGrb10, which included the IPS (insert between the PH and SH2 domain) and the SH2 domains, was found to bind with high affinity to the full-length protein. The interaction between the IPS/SH2 domain and the full-length hGrb10 was further confirmed by in vitro glutathione S-transferase fusion protein binding studies. Gel filtration assays showed that hGrb10 underwent tetramerization in mammalian cells. The interaction involved at least two functional domains, the IPS/SH2 region and the PH domain, both of which interacted with the NH2-terminal amino acid sequence of hGrb10gamma (hGrb10gamma DeltaC, residues 4-414). Competition studies showed that hGrb10gamma DeltaC inhibited the binding of hGrb10 to the tyrosine-phosphorylated insulin receptor, suggesting that this region may play a regulatory role in hGrb10/insulin receptor interaction. We present a model for hGrb10 tetramerization and its potential role in receptor tyrosine kinase signal transduction.

Alleviation of x-irradiation-based deficit in memory-based learning by D-amphetamine: suggestions for attention deficit-hyperactivity disorder

Selective exposure to x-irradiation during infancy, from postnatal days (PND) 2-11 in the rat, results in severe hippocampal granule cell hypoplasia. Preweanling (PND 17-18) rats, which suffer such hippocampal granule-cell agenesis, show deficits in patterned single alternation (PSA), a form of memory-based learning. Deficits in short-term memory along with increased arousal have been suggested as characteristic of children diagnosed with attention deficit-hyperactivity disorder (ADHD). We report here on the ameliorating effects of D-amphetamine, a drug commonly used in the treatment of ADHD, before Ritalin, on PSA, after infantile (PND 2-15) exposure to x-irradiation. After i.p. injections of 0.3 mg/kg D-amphetamine, the onset and magnitude of the PSA memory-based discrimination in the x-irradiated preweanling rats was restored to about the level of controls. These results, showing alleviation of x-irradiation-related deficits in short-term memory by D-amphetamine injections, along with our earlier and present results, showing substantial deficits after x-irradiation alone, encourage the hypothesis that hippocampal granule-cell hypoplasia, which would occur in humans prenatally and is Altman's model of "minimal brain dysfunction" [Altman, J. (1986) in Learning Disabilities and Prenatal Risk, ed. Lewis, M. (Univ. of Illinois Press, Urbana), pp. 241-304], may be a factor in at least some forms of ADHD and may provide a basis for an animal model of the disease.

Dermal oedema assessed by high frequency ultrasound in venous leg ulcers

Oedema is considered a key pathogenic factor in the development of venous leg ulcers. The purpose of this study was to determine the localization of oedema in legs with ulcers. Twelve patients with 13 venous leg ulcers (one bilateral), with a duration of 7-18 months, were examined by high-frequency B-mode ultrasound scanner. This was performed at three sites in the leg (low, middle and upper sites of the lower leg). In the same group of patients, the legs without ulcers were used as controls. The echogenicity and the thickness of the whole dermis were quantified by digital image analysis; the echogenicities of the upper (papillary) and lower portions of the dermis were measured. In the upper site no significant difference was found between the legs with ulcers and controls. In the middle and low sites of legs with ulcers, the dermal echogenicities were 34% and 64% (P < 0.01) less than those in controls, and the dermal thicknesses were 0.4 mm and 0.8 mm (P < 0.01) thicker than those in controls, respectively. This indicated intradermal oedema existing in the lower part (gaiter area) of the legs with ulcers. The ratios of low echogenic pixels in the upper and lower portions of the dermis, in the middle and low sites of legs with ulcers, were 0.5 and 0.9 (P < 0.05 and P < 0.01), respectively, higher than those in controls, suggesting the papillary dermis as a preferential site of oedema formation. The present study demonstrates that in the low sites of legs with ulcers, a marked increase in oedema was seen in the papillary dermis. This may add to the understanding of the origin of leg ulcers in the gaiter area of the leg.

[The inhibitory effect of antisense phosphorothioate c-myc oligodeoxynucleotide on intimal hyperplasia in rat abdominal aortae after injury with a balloon catheter]

OBJECTIVE

To evaluate the effect of Antisense phosphorothioate c-myc oligodeoxynucleotide (ODN) on intimal hyperplasia in rat abdominal aortae induced by endothenial-denuded injury with a balloon catheter.

METHODS

Antisense c-myc ODN was applied to the adventitia of injured abdominal aortae in rat introduced by pluronic gel releasing system and lipofectin delivery system. The animals were feeded with routine diet. Three weeks after intervention, the animals were killed and defined segments of arteries were sectioned and the histological sections were stained with elastic fiber staining. The cross-section of the artery was examined microscopically and the image was digitalized by image analysis system. The intima/media(I/M) area and I/M thickness ratios were calculated and analyzed statistically among groups.

RESULTS

The intimal hyperplasia in antisense c-myc ODN-treated rats was inhibited significantly, demonstrated by microscopically and I/M area and thichness ratios, as compared with that treated with sense c-myc ODN and mismatch c-myc ODN. The larger dose of antisense c-myc ODN, the more obvious the suppression of intimal hyperplasia.

CONCLUSION

The results suggest antisense c-myc ODN significantly suppressed the intimal hyperplasia in injured rat aortae in a sequence-specific fashion and dose-dependent manner. The investigation provides the basis for the early clinical trials assessing the therapeutic potential of antisense c-myc approach for the prevention of restenosis after angioplasty.

DNA vaccines encoding full-length or truncated Neu induce protective immunity against Neu-expressing mammary tumors

We generated DNA expression vectors encoding the full-length neu cDNA (designated pNeuN), the neu extracellular domain (pNeuE), or the neu extracellular and transmembrane domains (pNeuTM). The 293 cells transfected with pNeuN or pNeuTM expressed the neu extracellular domain on the surface membrane, whereas 293 cells transfected with pNeuE secreted the extracellular domain of neu into the culture supernatant. We examined whether i.m. injection of either of these plasmids could induce protective immunity in FVB/N mice against the adoptive transfer of Tgl-1 cells, a neu-expressing tumor cell line generated from a mouse mammary tumor that spontaneously arose in a FVB/N neu-transgenic mouse. The i.m. injection of pNeuTM or pNeuE, and to a lesser extent pNeuN, induced protective immunity against a subsequent challenge with Tgl-1 cells in FVB/N mice. In addition, the coinjection of a plasmid encoding interleukin-2 (designated pIL-2) augmented the efficacy of each of the pNeu plasmids for inducing protective immunity. The plasmid pNeuTM seemed to be the most effective for inducing anti-neu antibodies. However, the generation of detectable anti-neu antibodies in response to any one of these pNeu plasmids was not enhanced by coinjection of pIL-2 and was not required for protective immunity against Tgl-1 cells. These studies demonstrate that DNA expression vectors encoding soluble or membrane-bound forms of neu lacking the cytoplasmic kinase domain can be effective in inducing protective antitumor immunity.

[Analysis of chemical components from Pheretima]

The total fat, total nitrogens, free amino acids, inorganic elements of Pheretima have been determined. It will provide scientific evidence for the establishment of quality standards of pheretima.

The C. reinhardtii CF1 with the mutation betaT168S has high ATPase activity

We have generated the mutation T168S in the beta subunit of the chloroplast ATP synthase complex of Chlamydomonas reinhardtii by site directed mutagenesis and chloroplast transformation. CF1 and the alpha3beta3gamma complex of this mutant strain were isolated and their enzymatic activities were characterized and compared to those of the corresponding wild type complexes. Without activation the mutant CF1 exhibits MgATPase activity with at least 10 times higher rates than the wild type enzyme. The MgATPase activity could be stimulated to some extent by methanol, but less by ethanol and octylglucoside. The alpha3beta3gamma complex had an even higher MgATPase activity, which was only slightly enhanced by ethanol or methanol. The ATPase activities of the mutant complexes, like those of the wild type complexes, displayed a sharp concentration optimum for Mg2+. Free ADP inhibited neither the mutant nor the wild type ATPase significantly. Azide, which strongly inhibited the ATPase activity of the wild type enzyme, inhibited the mutant enzyme only at an about 30 times higher concentration suggesting that the mutation T168S prevents trapping of a tightly bound MgADP by a catalytic site that regulates chloroplast ATPase activity. The mutant cells grew photoautotrophically at a growth rate of about 50%. Similar to the wild type the cells survived on minimal medium in the dark. Under heterotrophic conditions with acetate as energy and carbon source the mutant cells grew much faster than the wild type cells, but the chlorophyll content per cell decreased dramatically.

An evaluation of linear model analysis techniques for processing images of microcirculation activity

Sequences of images of the cortical surface can be processed to reveal information about the cortical microcirculation, regional cerebral blood flow (rCBF), and changes induced by neuronal activity. This study examined the use of different analysis methodologies on intrinsic optical images taken from rat sensory motor cortex and testes. Generalized linear model (GLM) analysis was used and compared with standard signal processing methods including principal component analysis. The GLM method has been used by Friston et al. (1994, Hum. Brain Map., 1: 214-220) in the analysis of functional magnetic resonance imagery to identify regions of focal activity. We investigated the use of this method to analyze video image data of the modulation of rCBF from rat cortex. The results revealed spatiotemporal variations in rCBF in response to stimulation within local regions of cortex. The advantage of the GLM method is that it augments ordinary signal processing methods with an estimate of statistical reliability. The use of different wavelengths of illumination reveals spatial structures with different temporal relationships. In image time series data collected under green and red illumination a phase difference was found in the low frequency approximately 0.1 Hz vasomotion oscillation. This phase difference occurred in data from both cortex and testes. A possible explanation of these differences is that the spectral absorption characteristics of the tissue reflect changes in the volume proportions of the different hemoglobin derivatives in interacting with the modulation of the volume of blood. It is suggested that the combination of these effects produces the phase differences we detect.

The gene for severe combined immunodeficiency disease in Athabascan-speaking Native Americans is located on chromosome 10p

Severe combined immunodeficiency disease (SCID) consists of a group of heterogeneous genetic disorders. The most severe phenotype, T-B- SCID, is inherited as an autosomal recessive trait and is characterized by a profound deficiency of both T cell and B cell immunity. There is a uniquely high frequency of T-B- SCID among Athabascan-speaking Native Americans (A-SCID). To localize the A-SCID gene, we conducted a genomewide search, using linkage analysis of approximately 300 microsatellite markers in 14 affected Athabascan-speaking Native American families. We obtained conclusive evidence for linkage of the A-SCID locus to markers on chromosome 10p. The maximum pairwise LOD scores 4.53 and 4.60 were obtained from two adjacent markers, D10S191 and D10S1653, respectively, at a recombination fraction of straight theta=.00. Recombination events placed the gene in an interval of approximately 6.5 cM flanked by D10S1664 and D10S674. Multipoint analysis positioned the gene for the A-SCID phenotype between D10S191 and D10S1653, with a peak LOD score of 5.10 at D10S191. Strong linkage disequilibrium was found in five linked markers spanning approximately 6.5 cM in the candidate region, suggesting a founder effect with an ancestral mutation that occurred sometime before 1300 A.D.

Expression and cellular location of endothelin-1 mRNA in rat liver following endotoxemia

OBJECTIVE

To study the effect of endotoxin on the alteration of the transcription, expression and cellular location of endothelin-1 (ET-1) mRNA in the hepatic tissue.

METHODS

Wistar rats were divided into control and endotoxic group. The rats in the control group were injected with saline, and those in the endotoxic group with endotoxin at a dose of 10 mg.kg-1 body wt. ET-1 hepatic homogenate was assayed by radioimmunoassay at 3, 6, 9, 12 and 24 h after endotoxin administration. Dot blot was used to identify and quantify ET-1 mRNA of the hepatic tissue. Hybridization of ET-1 of the hepatic tissue was proceeded at 3, 6, 12 and 24 h after endotoxin administration.

RESULTS

ET-1 concentrations and the level of ET-1 mRNA increased rapidly and reached the peak at 6 h, and remained high at 24 h after endotoxin administration. By in situ hybridization, ET-1 mRNA was found in hepatic sinusoids, endothelial cells of portal vein and kupffer cells.

CONCLUSIONS

Endotoxin may be the principal stimulating factor for expression of ET-1 mRNA in hepatic tissue. Endotoxin may affect transcription and translation level of ET-1, leading to increase of the synthesis and release of ET-1. The hepatic vascular endothelial cells, hepatic sinusoids and Kupffer cells all synthesize and release ET-1.

[Efficacy of a triclosan/copolymer dentifrice in the control of plaque and gingivitis: a six-month study in China]

A total of one hundred fifty three healthy male and female adults were entered into a six month, double-blind clinical study designed to evaluate the effect of a dentifrice containing 0.3% triclosan and 2.0% PVM/MA copolymer in a 0.243% sodium fluoride/silica base, relative to a 0.243% sodium fluoride silica base control dentifrice on supragingival plaque accumulation and gingivitis. Plaque and gingivitis were scored after 3 and 6 months' use of the assigned dentifrice. At the end of the study, the dentifrice containing triclosan/copolymer demonstrated an average reduction, relative to the control dentifrice of 16.1% in plaque accumulation and 24.3% in gingivitis. Both were statistically significant(P < 0.001). It was concluded that the twice-daily use of the triclosan/copolymer containing dentifrice resulted in a significant reduction in plaque formation and a significant improvement in gingival health. No side-effects were observed.