Transferrin subtypes in 11 south China minority populations

Transferrin subtypes were determined by isoelectric focussing (IEF) in a total of 2,121 individuals from 11 South China minority populations. The C1, C2 and DCHI alleles were present in all the populations; B alleles were lacking, C4 was found in 3 populations and C3 in 6. C2 and C4 allele frequencies are notable in these minority groups. The frequency of the C2 allele was higher (0.25-0.38) than that of Han Chinese (0.18-0.25). In Bai the C2 frequency was as high as 0.38. The C4 allele was present at a low frequency (less than 0.01), which suggests that this allele probably existed in the ancestral Mongoloid population at a low frequency and increased in frequency in Amerindians due to genetic drift or other factors.

Irreversible inactivation of diacylglycerol kinase-II requires a mediator

Cytosolic diacylglycerol kinase was irreversibly inactivated by 5'-AMP since the enzyme remained less active after the removal of 5'-AMP by P-10 gel chromatography. The inactivation was time-dependent, suggesting the involvement of a covalent bond modification. A reconstitution experiment detected a rat brain cytosolic mediator for the effect of 5'-AMP. A protein kinase rich fraction prepared from rat liver was also capable of restoring the sensitivity of diacylglycerol kinase-II to 5'-AMP. We propose that 5'-AMP-activated protein kinase is the mediator which inactivates diacylglycerol kinase-II, possibly by phosphorylation.

Magnetic fields associated with anoxic depolarization in anesthetized rats

We have performed simultaneous measurements of the DC-magnetoencephalogram (DC-MEG) and DC-electrocorticogram (DC-ECoG) in rats (n = 6) subjected to 90 s of reversible anoxia. The onset of major shifts of electric and magnetic signals occurred at 52 +/- 18 (S.D.) and 68 +/- 14 (S.D.), respectively, and reached a peak at 83 +/- 27 and 102 +/- 19 (S.D.) s, respectively, after termination of mechanical ventilation. DC-ECoG signal deflections were always associated with DC-MEG deflections. The time of onset and peak signals in both DC-MEG and DC-ECoG changes caused by asphyxia were highly correlated (r + 0.83, 0.94; P less than 0.05, 0.001; respectively). Our observations suggest that the non-invasive technique of DC-MEG is reliable and may provide insight into the mechanisms of anoxic cerebral depolarization.

[Determination of the partial mean transit time with "convenient calculation" in young children]

A "convenient calculation" of MTTp = 0.1 FVC/2 Vp was derived from the principle of Jordanoglou to measure the partial mean transit time (MTTp). It was used to calculate the MTTp from the maximal expiratory flow volume (MEFV) curve of 342 healthy young children. The multiple regression equations were built with age, height and FVC as independent variables. The result showed that the MTTp of all children were elongated with the decay of lung volume with a similar rule as in the old, middle-aged and young people. No regular changes of MTTp in age groups were noticed. The regression equations showed that the MTTp of boys were positively correlated with FVC; while those of girls were negatively correlated with age; besides, MTT20-30% and MTT70-80% were positively correlated with FVC. The age and FVC just had the opposite effects so that little regular changes of MTTp occurred in the age groups.

Enhancer-binding activity of the tal-1 oncoprotein in association with the E47/E12 helix-loop-helix proteins

Almost 30% of patients with T-cell acute lymphoblastic leukemia (T-ALL) bear structural alterations of tal-1, a presumptive proto-oncogene that encodes sequences homologous to the helix-loop-helix (HLH) DNA-binding and dimerization domain. Analysis of the tal-1 gene product reveals that its HLH domain mediates protein-protein interactions with either of the ubiquitously expressed HLH proteins E47 and E12. The resultant tal-1/E47 and tal-1/E12 heterodimers specifically recognize the E-box DNA sequence motif found in eucaryotic transcriptional enhancers. Hence, the tal-1 protein shares biochemical properties with other tissue-specific HLH proteins that control cell type determination during myogenesis (e.g., MyoD1) and neurogenesis (e.g., achaete-scute). The data suggest that HLH heterodimers involving tal-1 may function in vivo as transcriptional regulatory factors that influence cell type determination during hematopoietic development.

Bispecific monoclonal antibodies directed to CD16 and to a tumor-associated antigen induce target-cell lysis by resting NK cells and by a subset of NK clones

CD16 surface antigens represent activatory molecules in CD3-16+ NK cells. In order to target NK cells against relatively NK-resistant ovarian carcinomas, we used an anti-CD16 monoclonal antibody (MAb) (VD4), together with an anti-ovarian carcinoma-associated antigen (MOV19), to construct biMAbs. To this end, hybrid hybridomas were generated by fusing a TK-deficient VD4 hybridoma mutant with a HGPRT-deficient MOV19 hybrid. Supernatants from hybrid hybridomas that had been selected in HAT medium were screened for their ability to induce a CD3-16+ NK clone to lyse an MOV19+ ovarian carcinoma cell line in a 4-hr 51Cr-release assay. The NMB.45 hybrid hybridoma secreted a biMAb which triggered lysis of MOV19+ but not of MOV19- target cells. Some degree of target cell lysis was also observed with MOV19 MAb (due to ADCC mechanisms), while the VD4 MAb was ineffective. HPLC fractionation of MAbs secreted by the hybrid hybridoma made it possible to identify 4 different peaks, one of which appeared to contain functional biMAb molecules. HPLC-purified biMAb (100 ng/ml) induced resting PBL to lyse the "NK-resistant" IGROVI ovarian carcinoma cell line. Fresh MOV19+ tumor cells were also lysed, although with lower efficiency. When IL-2-activated lymphocytes were used as a source of effectors, biMAb caused only minor increases in the IL-2-induced cytolytic activity. Further analyses of the effect of biMAb were performed at the clonal level. Among CD3-16+ NK cell clones, a clear enhancing effect could be observed only in GL183+ but not in GL183- clones. In CD3+ cytotoxic clones a triggering effect could be detected in one out of 4 TCR gamma/delta+ clones but not in TCR alpha/beta+ clones.

Regulation of chylomicron remnant uptake in the human hepatoma cell-line Hep G2. Role of the low-density lipoprotein receptor

Uptake and degradation of chylomicron remnants by the human hepatoma cell line Hep G2 was studied. Mesenteric lymph was collected from rats and injected into hepatectomized rats to obtain chylomicron remnants. This remnant preparation was taken up and catabolized by Hep G2 cells. The uptake process was dependent on cell growth and was regulated by compactin (a HMG-CoA reductase inhibitor) which suppresses cholesterol synthesis and by mevalonolactone, which enhances cholesterol synthesis. A monoclonal anti LDL receptor antibody blocked binding of chylomicron remnants to Hep G2 cells to a degree, which was comparable to but generally lower than the suppression of low-density lipoprotein binding. The results thus indicate that in Hep G2 cells, chylomicron remnant uptake is regulated, similarly to low-density lipoprotein uptake and that a significant part of the remnant uptake is mediated through the LDL receptor.

Neomycin inhibits the phosphatidylinositol monophosphate and phosphatidylinositol bisphosphate stimulation of plasma membrane ATPase activity

The inositol phospholipids, phosphatidylinositol monophosphate (PIP) and phosphatidylinositol bisphosphate (PIP(2)), have been shown to increase the vanadate-sensitive ATPase activity of plant plasma membranes (AR Memon, Q Chen, WF Boss [1989] Biochem Biophys Res Commun 162: 1295-1301). In this paper, we show the effect of various concentrations of phosphatidyinositol, PIP, and PIP(2) on the plasma membrane vanadate-sensitive ATPase activity. PIP and PIP(2) at concentrations of 10 nanomoles per 30 microgram membrane protein per milliliter of reaction mixture caused a twofold and 1.8-fold increase in the ATPase activity, respectively. The effect of these negatively charged phospholipids on the ATPase activity was inhibited by adding the positively charged aminoglycoside, neomycin. Neomycin did not affect the endogenous plasma membrane ATPase activity in the absence of exogenous lipids.

Analysis of conserved domains identifies a unique structural feature of a chloroplast heat shock protein

A low molecular weight heat shock protein which localizes to chloroplasts has been identified in several plant species. This protein belongs to a eukaryotic superfamily of small HSPs, all of which contain a conserved carboxyl-terminal domain. To investigate further the structure of this HSP, we isolated and sequenced cDNA clones for the chloroplast LMW HSPs from Petunia hybrida and Arabidopsis thaliana. The cloning of chloroplast HSPs from these two species enabled us to compare the amino acid sequences of this protein from plant species (petunia, Arabidopsis, pea, soybean and maize) that represent evolutionarily divergent taxonomic subclasses. Three conserved regions were identified, which are designated as regions I, II and III. Regions I and II are also shared by cytoplasmic LMW HSPs and therefore are likely to have functional roles common to all eukaryotic LMW HSPs. In contrast, consensus region III is not found in other LMW HSPs. Secondary structure analysis predicts that this region forms an amphipathic alpha-helix with high conservation of methionine residues on the hydrophobic face and 100% conservation of residues on the hydrophilic face. This structure is similar to three helices, termed "methionine bristles", which are found in a methionine-rich domain of a 54 kDa protein component of signal recognition particle (SRP54). The conservation of regions I and II among LMW cytoplasmic and chloroplast HSPs suggests that these HSPs perform related functions in different cellular compartments. However, identification of the methionine bristle domain suggests that chloroplast HSPs also have unique functions or substrates within the special environment of the chloroplast or other plastids.

The relationship between hepatic low-density lipoprotein receptor activity and serum cholesterol level in the human fetus

We found that the binding of 125I-low-density lipoprotein to fetal liver low-density lipoprotein receptor rose progressively with the increase in fetal age. During this period, total cholesterol and low-density lipoprotein-cholesterol levels in fetal serum declined significantly. The correlation coefficients between fetal age and concentration of serum total cholesterol and low-density lipoprotein cholesterol were -0.80 (p less than 0.001) and -0.77 (p less than 0.001), respectively. A significant inverse correlation also existed between the liver low-density lipoprotein receptor activity and the serum total cholesterol (r = -0.96, p less than 0.001) and low-density lipoprotein cholesterol (r = -0.95, p less than 0.001) but not high-density lipoprotein cholesterol. It is suggested that the low-density lipoprotein receptors in human fetal liver may play a key role in the regulation of the serum cholesterol levels during gestation.

[Effects of SC1001-sodium on hippocampal kindled seizures by coriaria lactone in rabbits]

Healthy rabbits weighing 1.7-2.4 kg were used. According to Sawyer's atlas the stainless steel cannula and recording electrode were implanted into the left hippocampus of each animal. The kindling experiments were started one week after the surgical operation. For kindling, all animals received injection of 2 microliters of diluted solution containing 0.55 or 0.32 microgram of coriaria lactone (CL) every second day, through the single stainless steel cannula previously implanted in the hippocampus. Hippocampal EEG of all the animals was recorded by telemetric method and the behavior of them was observed at the same time. Eighteen fully kindled rabbits were separated into three groups. The SC1001 Na group of six rabbits was treated with SC1001 Na (100 mg/kg, i.m.), the PB Na group (six rabbits) received phenobarbital Na (30 mg/kg, i.m.), and the control group of six was treated with placebo (normal saline, i.m., in the same volume as that of the SC1001 Na injection); injections were administered once a day for two courses of treatment (one course of treatment was 1 week). The results of the experiment indicated that SC1001 Na (100 mg/kg) had certain effects on hippocampal kindled seizures induced by CL, but its curative effects were not more notable than those of PB Na (30 mg/kg).

Histopathological, cytogenetic, and molecular characterization of renal cortical tumors

We used cytogenetic and restriction fragment length polymorphism (RFLP) analysis methods to define genetic alterations and also correlate the changes with histopathology in renal cortical tumors. The study series is comprised of 50 renal tumors in 4 histological categories: (a) clear cell, nonpapillary, renal cell carcinoma (RCC) (n = 32); (b) nonclear cell, nonpapillary RCC (n = 10); (c) papillary RCC (n = 3); and (d) oncocytic tumors (n = 5). Successful karyotypes were obtained from 28 tumors (56%), of which 17 (61%) were abnormal. Abnormalities of chromosome 3p were seen in 9 tumors, which included unbalanced translocations and terminal or interstitial deletions. Abnormalities of chromosome 5 were identified in 11 tumors, 8 of which were due to unbalanced translocations between 3p and 5q, resulting in an extra copy for the region 5q22----ter. In addition, trisomy or tetrasomy of chromosome 17 was seen in 6 (5 with normal chromosome 3 and one with 3p deletion), trisomy or more copies of chromosome 7 in 8 (4 with 3p deletion, 2 with trisomy or tetrasomy 17, and 2 with trisomy alone), and trisomy 12 in 3 (all with trisomy 17) tumors. Furthermore, relative deficiency of chromosome 17p was seen in 3 (all with deletion 3p) and chromosome 18 in 4 (all with deletion 3p) tumors. RFLP analysis with four chromosome 3 specific probes detected 3p deletions in 19 tumors with the most common breakpoint located between 3p14-21. The 19 3p deletions detected by RFLP included tumors that also showed rearrangement of 3p by cytogenetics (n = 4) and those that showed normal karyotypes (n = 3) in addition to cytogenetic failures (n = 12). Deletions of 17p were seen in 5 of 31 informative cases. Thus, deletions of 3p were seen in a total of 24 tumors by cytogenetic and/or RFLP analysis, 21 of which were clear cell, nonpapillary RCC, whereas 3 had a minor clear-cell component. Oncocytic and nonclear, nonpapillary tumors, on the other hand, did not demonstrate 3p deletions by either technique, whereas trisomy 17 was seen in 3 of the 3 papillary tumors. The loss of alleles from chromosome 17p and 18 and an increased dosage of gene or genes on chromosomes 5q and 7 as seen in high-stage tumors of various histological subtypes may be associated with progression of disease.

Inhibition of iodoacetamide and t-butylhydroperoxide toxicity in LLC-PK1 cells by antioxidants: a role for lipid peroxidation in alkylation induced cytotoxicity

Previously we reported that thiol depletion and lipid peroxidation were associated with the cytotoxicity of nephrotoxic cysteine S-conjugates, a group of toxins which kill LLC-PK1 cells after metabolic activation and covalent binding. To determine if this is a general mechanism of cytotoxicity in these cells, we compared the effect of antioxidants, an iron chelator, and a thiol reducing agent on the toxicity of an alkylating agent, iodoacetamide (IDAM), and an organic peroxidant, t-butylhydroperoxide (TBHP). IDAM or TBHP toxicity was concentration (0.01 to 1.0 mM) and time (1 to 6 h) dependent. Both toxins caused lipid peroxidation which occurred prior to cell death as determined by leakage of lactate dehydrogenase (LDH). The alkylating agent IDAM bound to cellular macromolecules and depleted cellular non-protein thiols almost completely by 1 h, while LDH release occurred first at 2 to 3 h. The toxicity of IDAM and TBHP was inhibited by the antioxidants DPPD, BHA, BHQ, PGA, and BHT and the iron chelator deferoxamine. However, DPPD blocked TBHP- and IDAM-induced lipid peroxidation and toxicity without affecting binding and depletion of cellular nonprotein thiols. Furthermore, the thiol reducing agent dithiothreitol was able to block lipid peroxidation and toxicity. Therefore it is possible that with an alkylating agent, depletion of cellular nonprotein thiols cooperates with covalent binding and contributes to lipid peroxidation and cell death. There appear to be common elements in the toxicity of alkylating agents and organic peroxidants in LLC-PK1 cells.

Induction of synaptic development in cultured muscle cells by basic fibroblast growth factor

The role of basic fibroblast growth factor (bFGF) in signaling the development of the neuromuscular junction was examined. Beads coated with bFGF induced the formation of acetylcholine receptor (AChR) clusters in cultured Xenopus myotomal muscle cells. Tyrphostin, a tyrosine kinase inhibitor, abolished AChR clustering induced by bFGF beads, suggesting a role of tyrosine kinase activation in AChR clustering. Using specific antibodies, we demonstrated the presence of both bFGF and its receptor in the myotomal muscle in vivo during the period of neuromuscular connection. However, similar tissue from older animals with mature neuromuscular junctions showed an apparently truncated form of the bFGF receptor. These data suggest that bFGF may play a role in signaling synaptogenesis in skeletal muscle.

[Effect of pulsed electromagnetic field on orthodontic tooth movement through transmission electromicroscopy]

This experiment is to observe the effect of pulsed electromagnetic field (PEMF) on orthodontic tooth movement of guinea pigs through transmission electron microscope (TEM). 14-days observations indicate that PEMF could accelerate the rate of orthodontic tooth movement as a result of the increase in quantity of active cell without changing the ultrastructures of cells and have no unfavorable effects on periodontal tissues.

The mechanism of cysteine conjugate cytotoxicity in renal epithelial cells. Covalent binding leads to thiol depletion and lipid peroxidation

Nephrotoxic cysteine conjugates kill cells after they are metabolized by the enzyme cysteine conjugate beta-lyase to reactive fragments which bind to cellular macromolecules. We have investigated the cellular events which occur after the binding and lead ultimately to cell death in renal epithelial cells. Using S-(1,2-dichlorovinyl)-L-cysteine (DCVC) as a model conjugate, we found that the phenolic antioxidants N,N'-diphenyl-p-phenylenediamine (DPPD), butylated hydroxyanisole, butylated hydroxytoluene, propyl galate, and butylated hydroxyquinone, and the iron chelator deferoxamine inhibited the cytotoxicity significantly. Among the five antioxidants, DPPD was most potent. DPPD blocked DCVC toxicity over an extended time period, and the rescued cells remained functional as measured by protein synthetic activity. DPPD was able to block the toxicity of two other toxic cysteine conjugates S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine and S-(1,1,2,2-tetrafluoroethyl)-L-cysteine. In addition to LLC-PK1 cells, DPPD also protected freshly isolated rat kidney epithelial cells in suspension and in primary culture. In suspension cells, DPPD was effective at low doses of DCVC (25-50 microM) but not at high concentrations (250-500 microM). DPPD inhibition was not due to an inactivation of beta-lyase or a decrease in the binding of [35S]DCVC metabolites to cellular macromolecules and occurred at a step after the activation of the toxins. During DCVC treatment, lipid peroxidation products were detectable prior to cell death. DPPD blocked lipid peroxidation over the whole time course. Depletion of nonprotein thiols also occurred prior to cell death. DPPD did not prevent the loss of nonprotein thiols. However, the sulfhydryl-reducing agent DTT blocked lipid peroxidation and toxicity at a step after the activation of DCVC. Therefore, it appears that cysteine conjugates kill renal epithelial cells by a combination of covalent binding, depletion of nonprotein thiols, and lipid peroxidation.

Short-term treatment with cell wall degrading enzymes increases the activity of the inositol phospholipid kinases and the vanadate-sensitive ATPase of carrot cells

Treating carrot (Daucus carota L.) suspension culture cells with a mixture of cell wall degrading enzymes, Driselase, resulted in an increase in the percentage of [(3)H]phosphatidylinositol bisphosphate. Analysis of the lipid kinase activities in the isolated plasma membranes after whole cell treatment indicated that treatment with Driselase (2% weight/volume; the equivalent of 340 units per milliliter of hemicellulase and 400 units per milliliter of cellulase activity) or treatment with hemicellulase (31.7% weight/volume, 20.7 units per milliliter) resulted in an increase in the inositol phospholipid kinase activity. However, treatment with cellulase alone had no effect at 0.5% (weight/volume, 17.2 units per milliliter) or inhibited the kinase activity at 1% (weight/volume, 34.4 units per milliliter). The active stimulus in Driselase was heat sensitive. The plasma membrane vanadate-sensitive ATPase activity also increased when the cells were treated with Driselase. A time course study indicated that both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase responded to as little as 5 seconds of treatment with 2% Driselase. However, at the lowest concentration of Driselase (0.04%, weight/volume) that resulted in an increase in inositol phospholipid kinase activity, the ATPase activity was not affected. Because inositol phospholipids have been shown to activate the vanadate-sensitive ATPase from plants (AR Memon, Q Chen, WF Boss [1989] Biochem Biophys Res Commun 162: 1295-1301), a stimulus-response pathway involving both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase activity is discussed.

[Microsurgery to treat lesions in or near the eyeball wall]

Four sub-retinal cysticerci and 12 cases of nonmagnetic intraocular foreign bodies near the eyeball wall were first localized with indirect ophthalmoscopy and then removed successfully under surgical microscopy. Three layers, ie white sclera, black supra-choroid pigment and light brown choroidal tissue with white vascular pattern were encountered before reaching the sub-retinal larval. The ischemic appearance of the choroid probably was caused by compression of the larval underneath it. Intraocular foreign bodies usually appeared in the wound accompanied by liquified vitreous as soon as the incision was made. If intraocular inflammation exist, foreign body can be found within the pus or dense exudates.

Coding sequences of the tal-1 gene are disrupted by chromosome translocation in human T cell leukemia

The tal-1 proto-oncogene encodes a helix-loop-helix DNA-binding protein that has been implicated in the formation of T cell acute lymphoblastic leukemia (T-ALL). Patients with T-ALL harbor structural rearrangements of tal-1 that result from either local DNA deletion or t(1;14)(p34;q11) chromosome translocation. By analyzing t(1;14)(p34;q11) chromosomes from a series of patients, we have now identified a discrete region of tal-1 wherein most of the translocation breakpoints occur. Moreover, mapping of tal-1 genomic DNA revealed that coding exons are situated on both sides of the t(1;14)(p34;q11) major breakpoint region. Hence, the translocated allele of tal-1 is truncated in a manner that reduces its amino acid coding potential.

Chronic metabolic measurements of normal brain tissue response to photodynamic therapy

The metabolic response of normal rat brain to photodynamic therapy (PDT) was studied over a 1 week interval using in vivo 31P-NMR spectroscopy. Rats injected with 12.5 mg/kg Photofrin II were submitted to brain photoactivation 48 h after drug administration with either 140 or 70 J/cm2 light (630 +/- 1 nm) from an Argon dye laser. Control studies, animals not given drug or light, animals submitted only to brain illumination without drug, and animals given drug but no light, were also performed. The data revealed a transient metabolic degradation; a decrease in the ratio of beta-nucleotriphosphate to inorganic phosphate (P less than 0.001) at 24 h after PDT treatment was followed by a return to pretreatment spectral values. Brain tissue alkalosis was also noted, with significant (P less than 0.05) differences in brain tissue pH detected at 72 h post treatment between 70 J/cm2 PDT vs control studies and at 1 week post treatment between 140 J/cm2 vs 70 J/cm2, 140 J/cm2 vs no light-no drug and 140 J/cm2 vs drug only. The data suggest that there is no difinitive metabolic marker from 31P-NMR spectroscopy that can identify necrotic brain tissue caused by PDT. Phosphorus-31 NMR data are also presented which suggest that PDT damage to brain is not solely the result of microvascular occlusion causing ischemic necrosis.

Arachidonic acid absorption in human jejunum in organ culture: effects of ethanol

Human jejunal tissue obtained by peroral biopsy was cultured in control medium and in medium containing 100 mmol l-1 ethanol. Subsequently, the incorporation and metabolism of [3H]-arachidonic and [14C]-linoleic acid were evaluated. Of the two fatty acids a significantly higher amount of [3H]-arachidonic acid was incorporated into phospholipids and more [14C]-linoleic acid was incorporated into triacylglycerols. This preferential distribution of the labelled fatty acids was not affected by ethanol, but when ethanol was present in the tissue culture medium, there was a significant decrease in the incorporation of both fatty acids into tissue phospholipids. The study thus shows that ethanol in moderate concentrations can affect human jejunal absorption and metabolism of polyenoic fatty acids, contributing to a decrease in the amount of eicosanoid precursors available in jejunal tissue.

Site-specific recombination of the tal-1 gene is a common occurrence in human T cell leukemia

The tal-1 gene is altered as a consequence of the t(1;14) (p32;q11) chromosome translocation observed in 3% of patients with T cell acute lymphoblastic leukemia (T-ALL). tal-1 encodes a helix-loop-helix (HLH) domain, a DNA binding and dimerization motif found in a number of proteins involved in cell growth and differentiation. We now report that an additional 25% of T-ALL patients bear tal-1 gene rearrangements that are not detected by karyotype analysis. These rearrangements result from a precise 90 kb deletion (designated tald) that arises independently in different patients by site-specific DNA recombination. Since the deletion junctions resemble the coding joints of assembled immunoglobulin genes, tald rearrangements are likely to be mediated by aberrant activity of the immunoglobulin recombinase. Moreover, t(1;14)(p32;q11) translocations and tald rearrangements disrupt the coding potential of tal-1 in an equivalent manner, and thereby generate a common genetic lesion shared by a significant proportion of T-ALL patients.

[A kindling model of epilepsy induced by intraperitoneal injection of coriaria lactone in rats]

Fifty adult male Sprague-Dawley rats were divided into five groups. Intraperitoneal injections of various doses of coriaria lactone (CL, 0.75, 1.25, 1.75, and 2.0 mg/kg) and normal saline were given respectively per 2 days. The behavior of the rats was observed and the ECoG was recorded by telemetric method. The results of experiments show that a kindling model of epilepsy can be established by intraperitoneal injection of CL in rats. This chronic experimental model is of value for application because it is easily established and the rate of being kindled is relatively high, but the mortality is low, and the kindling effect can last well. The model can avert the pathological change caused by artificial injury to brain, so it is advantageous to the research on neurochemistry and ultrastructure. In our experimental condition, it is optimal to select 1.25 mg/kg or 1.75 mg/kg as the dosage of CL for establishing kindling model.

Indirect inactivation of rat brain cytosolic diacylglycerol kinase by nucleoside-5'-monophosphate

Cytosolic diacylglycerol kinase was inhibited drastically by nucleoside monophosphate. The inhibition was relatively specific for adenosine-5'-monophosphate (5'-AMP), although uridine-5'-monophosphate was also effective. The effect of 5'-AMP on diacylglycerol kinase appeared to be indirect since the degree of inhibition lessened with the dilution of the cytosol and the more purified enzyme failed to respond to 5'-AMP. A 5'-AMP-dependent mediator is proposed to be involved in the inactivation of diacylglycerol kinase.

Accumulation, stability, and localization of a major chloroplast heat-shock protein

Diverse higher plant species synthesize low molecular weight (LMW) heat shock proteins (HSPs) which localize to chloroplasts. These proteins are homologous to LMW HSPs found in the cytoplasm of all eukaryotes, a class of HSPs whose molecular mode of action is not understood. To obtain basic information concerning the role of chloroplast HSPs, we examined the accumulation, stability, tissue specificity, and intra-chloroplast localization of HSP21, the major LMW chloroplast HSP in pea. Intact pea plants were subjected to heat stress conditions which would be encountered in the natural environment and HSP21 mRNA and protein levels were measured in leaves and roots. HSP21 was not detected in leaves or roots before stress, but the mature, 21-kD protein accumulated in direct proportion to temperature and HSP21 mRNA levels in both tissues. All of the HSP21 in leaves was localized to chloroplasts; there was no evidence for its transport into other organelles. In chloroplast fractionation experiments, greater than 80% of HSP21 was recovered in the soluble chloroplast protein fraction. The half-life of HSP21 at control temperatures was 52 +/- 12 h, suggesting the protein's function is critical during recovery as well as during stress. We hypothesize that HSP21 functions in a catalytic fashion in both photosynthetic and nonphotosynthetic plastids.

A protein homologous to the Torpedo postsynaptic 58K protein is present at the myotendinous junction

The 58K protein is a peripheral membrane protein enriched in the acetylcholine receptor (AChR)-rich postsynaptic membrane of Torpedo electric organ. Because of its coexistence with AChRs in the postsynaptic membrane in both electrocytes and skeletal muscle, it is thought to be involved in the formation and maintenance of AChR clusters. Using an mAb against the 58K protein of Torpedo electric organ, we have identified a single protein band in SDS-PAGE analysis of Xenopus myotomal muscle with an apparent molecular mass of 48 kD. With this antibody, the distribution of this protein was examined in the myotomal muscle fibers with immunofluorescence techniques. We found that the 48K protein is concentrated at the myotendinous junctions (MTJs) of these muscle fibers. The MTJ is also enriched in talin and vinculin. By double labeling muscle fibers with antibodies against talin and the 48K protein, these two proteins were found to colocalize at the membrane invaginations of the MTJ. In cultured myotomal muscle cells, the 48K protein and talin are also colocalized at sites of membrane-myofibril interaction. The 48K protein is, however, not found at focal adhesion sites in nonmuscle cells, which are enriched in talin. These data suggest that the 48K protein is specifically involved in the interaction of myofibrillar actin filaments with the plasma membrane at the MTJ. In addition to the MTJ localization, 48K protein is also present at AChR clusters both in vivo and in vitro. Thus, this protein is shared by both the MTJ and the neuromuscular junction.

Effects of human pancreatic lipase-colipase and carboxyl ester lipase on eicosapentaenoic and arachidonic acid ester bonds of triacylglycerols rich in fish oil fatty acids

Fish oil chylomicrons, obtained from mesenteric duct chyle of rats fed [3H]20:5 and [14C]20:4 or [3H]20:5 and [14C]18:2 in a fish oil emulsion, were incubated with human pancreatic lipase-colipase, human carboxyl ester lipase (CEL) and human duodenal contents. With duodenal contents, the triacylglycerols labelled with [3H]20:5 and [14C]20:4 were rapidly converted to free fatty acids (FFA) and monoacylglycerols. Also during incubation with lipase-colipase the [3H]- and [14C]triacylglycerols disappeared completely and at equal rates, but in this case much [3H]20:5 and [14C]20:4 accumulated in diacylglycerols. When CEL was also added, the rate of disappearance of [3H]- and [14C]triacylglycerols increased and the radioactivity of diacylglycerols decreased markedly. During incubation of chylomicrons labelled with [3H]20:5 and [14C]18:2 with lipase-colipase, the rates of hydrolysis of [3H]- and [14C]triacylglycerols were similar, but more [3H]20:5 than [14C]18:2 accumulated in diacylglycerols. The accumulation of [3H]diacylglycerol was reduced by adding CEL. Also when fatty acids were analyzed by gas chromatography, 20:5 was enriched in remaining triacylglycerol and in diacylglycerol after incubation with lipase-colipase alone. The data thus indicate that both lipase-colipase and CEL participate in the hydrolysis of 20:5 and 20:4 ester bonds of dietary triacylglycerol.

[Bioelectric potentials of bone in experimental fracture healing]

A specific electric potential gradient exists on the surface of long bone and the electric gradient changes after fracture. The electric potentials at the fracture site were measured and it was shown to change most actively during the early healing phase, and thereafter reached the normal level gradually. When soft tissue was damaged, certain potential changes occurred. But this change was different from that in the fracture site, indicating that the tissue has "biological window" effect of electrization.

[Electron microscopic observation of the effects of Rhodiola kirilowii (Regel.) Maxim. in preventing damage of the rat viscera by a hypoxic high altitude environment]

This paper has shown that the pathologic damages done to rat's viscera due to hypoxic environment of altitude can be reduced significantly by oral administrations of Shengmaiyin, Danshen-Chuanxiong mixture and Rhodiola kirilowii. Shengmaiyin that maintains interior substances in the plate layer bodies proves more effective than Danshen-Chuanxiong mixture, while the latter excels in preventing capillary contraction, thus improving blood circulation. Rhodiola kirilowii has the effects of both Shengmaiyin and Danshen-Chuanxiong mixtures.

[Measurement and clinical application of MEFV and PEFV curves in young children]

Previous studies of children's ventilatory functions revealed that a history of pediatric respiratory illness could cause an adult airway to be highly susceptible to the adverse effects of a variety of bronchial stimulants and infectious agents and easy to develop obstructive airway diseases in adult life. Ten indexes of ventilatory function were measured with MEFV and PEFV curves in 333 normal young children aged between 3 and 6, and 15 sick children of bronchopneumonitis in the same age range. Multiple regression equations of different indexes of normal children were set up. The measured values of various indexes of the sick children were much lower than the correspondent predicted values calculated from multiple regression equations, especially VT, VmaxFRC and VmaxFRC/FRC (P less than 0.05). The results suggest that the measurement of PEFV is a convenient and sensitive method to test children's ventilatory function.

The tal gene undergoes chromosome translocation in T cell leukemia and potentially encodes a helix-loop-helix protein

We have analyzed t(1;14)(p32;q11) chromosome translocations from two patients with T cell acute lymphocytic leukemia. The chromosome 1 breakpoints of these patients lie within a kilobasepair of each other, and thus define a genetic locus (designated tal) involved in T cell oncogenesis. Moreover, we have identified sequences within tal that potentially encode an amphipathic helix-loop-helix motif, a DNA-binding domain found in a variety of proteins that control cell growth and differentiation. The homology domain of tal is especially related to that of lyl-1, a gene on chromosome 19 that has also been implicated in T cell oncogenesis. Hence, tal and lyl-1 encode a distinct family of helix-loop-helix proteins involved in the malignant development of lymphocytes.

[Mitochondrial encephalomyopathy. Report of a case]

A typical case of mitochondrial encephalomyopathy with lactic acidemia and stroke-like episodes (MELAS) was reported. The main clinical manifestations consisted of short stature, psychomotor deterioration, sensorineural deafness, and hemiparesis. The laboratory findings disclosed abnormal lactic acid tolerance abnormal EEG, VEP, AEP, SEP, and MCV. The CT scan showed multiple intracerebral infarcts, basal ganglia calcifications, and cerebral atrophy. A muscle biopsy was performed. The frozen sections with modified gomori trichrome stain revealed ragged-red-fiber which reacted strongly positive in NADH-TR stain. The electron microscopy revealed subsarcolemmal aggregation of mitochondria of various sizes with paracrystalline inclusions, abnormally arranged cristae, and osmiophilic dense-bodies in their matrices.

Normal brain tissue response to photodynamic therapy: histology, vascular permeability and specific gravity

The response of photodynamic therapy on normal brain was investigated in 140 Fisher rats. The rats were injected i.p. with Photofrin II (12.5 mg/kg) and 48 h later the dural area over the frontal cortex was photoactivated with red light (630 +/- 1 nm) from an argon dye laser. Treatment was performed with optical energy densities of 140 and 70 J/cm2. Histopathology, vascular permeability and specific gravity measurements were conducted on different populations of rats at 4 h, 24 h, 72 h and 1 week after photodynamic therapy (PDT). Histopathology revealed similar gross and microscopic pathology associated with light energies of 70 and 140 J/cm2 after all time points. A large cerebral infarct approximately the size of the brain surface area treated, evolved 24 h following treatment. Evans blue extravasation indicated a small area of vascular permeability evident as early as 4 h following PDT treatment at both energy levels, with increasing permeability evident at later time points. Specific gravity measurements taken on a representative area of the lesion indicated a significant (P less than 0.01) amount of edema present at 24 h post treatment with a gradual reduction approaching control values over the time period of 1 week. The data indicate a significant amount of damage to normal brain from low PDT treatment doses.

Quantitative benedict test using bicinchoninic acid

Cupric ion (Cu2+), in complex form, functions as a selective oxidizing agent for a variety of compounds in the qualitative Benedict test. Cupric ion is reduced to cuprous ion (Cu+) in the reaction. We found that the cuprous ion formed in this type of redox reaction could be detected and quantified using 2,2'-bicinchoninic acid. This reagent produced an intense purple complex with cuprous ion. The color development in this modified Benedict test was dependent on pH, temperature, and time. The reaction is insensitive to ethanol and sodium dodecyl sulfate. This improved method of the Benedict test has enhanced sensitivity and makes the quantitation of compounds possible. This method should be useful for studies of Benedict-positive compounds which are available only in small amounts.

Hydrolysis of triacylglycerol arachidonic and linoleic acid ester bonds by human pancreatic lipase and carboxyl ester lipase

The hydrolysis of polyenoic fatty acid ester bonds with pure human colipase-dependent lipase, with carboxyl ester lipase (CEL) and with these enzymes in combination was studied, using [3H]arachidonic- and [14C]linoleic acid-labelled rat chylomicrons as a model substrate. During the hydrolysis with colipase-dependent lipase, the amount of 3H appearing in 1,2-X-diacylglycerol (DG) markedly exceeded that of 14C. When CEL was added in addition this [3H]DG was efficiently hydrolyzed. CEL alone hydrolyzed the triacylglycerol (TG) at a low rate. The hydrolysis pattern with human duodenal content was similar to that seen with colipase-dependent lipase and CEL in combination. Increasing the concentration of taurodeoxycholate (TDC) and taurocholate (TC) or of TDC alone stimulated the hydrolysis of [3H]- and [14C]TG, but increased the accumulation of labelled DG that could act as substrate for CEL. It is suggested that very-long-chain polyenoic fatty acids of DG formed during the action of the colipase-dependent lipase on TG containing these fatty acids may be a physiological substrate for CEL.

Molecular cloning and expression of Bacillus thuringiensis subsp. galleriae insecticidal crystal protein genes in Escherichia coli

The location of the toxin gene of B. thuringiensis subsp. galleriae (H5ab) on the Mr-130Md plasmid is determined by molecular cloning. Double digestion fragments (BamHI and SalI) and PstI restriction fragments as well, from the 130 Md plasmid, of B. thuringiensis subsp. galleriae, are ligated with the cloning vector pAT 153 respectively and transformed into E. coli strain HB 101. Out of 208 transformants, three colonies (FG2, FG9, FG19) give positive hybridization reaction using the HD-1 delta-endotoxin gene as a probe. They are presumed to contain the delta-endotoxin gene of B. thuringiensis subsp. galleriae. Western blot assays indicate that Mr-130 kDal and 68 kDal, crystal proteins produced by clone FG2 react with anticrystal protein antibody. The protein extracts of clone FG2 are lethal to Ostrinia furnacalis (Guenee). This is the first report with regard to the cloning and expression of the B. thuringiensis subsp. galleriae (H5ab) delta-endotoxin gene.