Efficient lymphocyte migration across high endothelial venules of mouse Peyer's patches requires overlapping expression of L-selectin and beta7 integrin

Lymphocyte migration into lymphoid organs is regulated by adhesion molecules including L-selectin and the beta7 integrins. L-selectin and alpha4beta7 are predominantly hypothesized to direct the selective migration of lymphocytes to peripheral lymph nodes and the gut-associated lymphoid tissues, respectively. To further characterize interactions between L-selectin and beta7 integrins during lymphocyte recirculation, mice deficient in both receptors (L-selectin/beta7 integrin-/-) were generated. The simultaneous loss of L-selectin and beta7 integrin expression prevented the majority of lymphocytes (>95% inhibition) from attaching to high endothelial venules (HEV) of Peyer's patches and other lymphoid tissues during in vitro binding assays. Moreover, the inability to bind HEV eliminated the vast majority of L-selectin/beta7 integrin-/- lymphocyte migration into Peyer's patches during short-term and long-term in vivo migration assays (>99% inhibition,p < 0.01). The lack of lymphocyte migration into Peyer's patches correlated directly with the dramatically reduced size and cellularity (99% reduced) of this tissue in L-selectin/beta7 integrin-/- mice. High numbers of injected L-selectin/beta7 integrin-/- lymphocytes remaining in the blood of wild-type mice correlated with markedly increased numbers of circulating lymphocytes in L-selectin/beta7 integrin-/- mice. Loss of either L-selectin or the beta7 integrins alone resulted in significant but incomplete inhibition of Peyer's patch migration. Collectively, the phenotype of L-selectin/beta7 integrin-/- mice demonstrates that these two receptors primarily interact along the same adhesion pathway that is required for the vast majority of lymphocyte migration into Peyer's patches.

An increase in apparent affinity for sucrose of mung bean sucrose synthase is caused by in vitro phosphorylation or directed mutagenesis of Ser11

A mutational analysis of mung bean (Vigna radiata Wilczek) sucrose synthase was performed by site-directed mutagenesis of the recombinant protein expressed in Escherichia coli, in which two different acidic amino acid residues (Asp or Glu) were introduced at Ser11 (S11D, S11E). Only the wild-type enzyme (Ser11) was phosphorylated in vitro by a Ca(2+)-dependent protein kinase from soybean root nodules, suggesting that this is the specific target residue in mung bean sucrose synthase. The apparent affinity for sucrose was increased in this phosphorylated enzyme and also in the S11D and S11E mutant enzymes, although the affinities for UDP-glucose and fructose were similar in the wild-type, phosphorylated wild-type, and mutant enzymes. These results suggest that a monoanionic (1-) side chain at position 11 mimics the Ser11-P2- residue to bind and cleave sucrose for the synthesis of UDP-glucose. Since the S11E mutant enzyme showed the lowest K(m) (sucrose) and the highest catalytic efficiency of the recombinant proteins, the enzymic properties of this S11E mutant were further characterized. The results showed that replacement of Ser11 with Glu11 modestly protected the sucrose synthesis activity against phenolic glycosides and altered the enzyme nucleotide specificity. We postulate that the introduction of negative charge at Ser11 is possibly involved in the enzymatic perturbation of sucrose synthase.

In vivo and in vitro studies on the antitumor activities of MCP (Malva crispa L. Powder)

Four short-term in vivo and in vitro tests were used to further confirm the antitumor activities of MCP, a vegetable powder, prepared from Malva crispa L. (i) In the H22 hepatoma-transplanting test, MCP had antitumor action, but MCP residue did not show such action; 5-FU appeared to have more potent antitumor activities and more harmful effects than MCP. (ii) In the micronucleus (MN) test, MCP significantly decreased MN frequency. (iii) In the cancer cell culture systems, the MCP fat-soluble extract revealed inhibitory effects on the growth and proliferation of the human hepatoma and the gastric cancer cells in a dose-response manner. (iv) In the colony formation test, MCP also altered the morphology of human gastric cancer cells. It was suggested that MCP could be consumed not only by healthy subjects for cancer prevention but also by patients with cancer as supplementary treatment in combination with anticarcinogenic drug such as 5-FU, cyclophosphamide (CP).

[The relationship between protein synthesis of Sindbis virus and host cytoskeletons]

In our experiments, protein synthesis of host cells were inhibited quickly at the early stage of infection by Sindbis virus. Polysome and mRNA of host cell fell off from cytoskeletons, whereas virus RNA bound up. We also found it was via 3'-terminal that virus RNA bound with cytoskeleton. After studying on the virus nonstructural proteins, we found the synthesis and processing of virus protein in vitro were far slowly than in vivo, and most of proteins were premature. So, the cytoskeletons may play an important role there. After treated with colchicine and cytochalasin B, the microtubule and microfilament were destroyed. However, the synthesis and processing of nonstructural proteins of Sindbis virus didn't change much, while the structural proteins were inhibited largely. These results showed the differences of dependence of the synthesis of the two kinds of proteins on cytoskeletons. Microtubule and microfilament may be more important to the synthesis of structural proteins than to that of the nonstructural proteins.

The 3' breakpoint of the yunnanese (Agammadeltabeta)0-thalassemia deletion lies in an L1 family sequence: implications for the mechanism of deletion and the reactivation of the Ggamma-globin gene

We have cloned the junction region of the previously characterized Yunnanese (Agammadeltabeta)0-thalassemia deletion and the normal DNA region surrounding its 3' breakpoint. The sequence of 1138 bp of the 3'-flanking region and 555 bp of the normal region surrounding the 3' breakpoint was determined. The 5' breakpoint of the deletion is positioned between 116 and 117 bp upstream of the Agamma-globin gene, and the 3' breakpoint at 34 bp downstream of the BglII site that lies approximately 12.7 kb upstream of the 3' deletion breakpoint of Chinese (Agammadeltabeta)0-thalassemia. There is no significant homology between the normal DNAs flanking the 5' and 3' breakpoints, except 2-bp (TG) identity and two pairs of short direct repeats at the deletion junction. The 3' breakpoint is within an L1 family sequence that normally occurs about 66 kb downstream of the beta-globin gene in 11p15. This L1 element is partially in reversed orientation at the 5' side and is therefore, presumably, an inactive element. This type of junction indicates illegitimate DNA breakage and end-joining involving the L1 sequence. Similar to many other deletions in the beta-globin locus, the Yunnanese (Agammadeltabeta)0-thalassemia deletion lacks a sequence characteristic of defined recombination factors near the deletion junction, suggesting that chromatin configuration and other locus-specific features are important. Computer-aided analysis revealed that several transcriptional factors could bind to putative motifs present in the 3'-flanking sequence. It is possible that binding features of the distal L1 element are required to generate a suitable chromatin configuration for the recombination event in Yunnanese (Agammadeltabeta)0-thalassemia. This may also be related to the reactivation of the Ggamma-globin gene in adults with the Yunnanese (Agammadeltabeta)0-thalassemia mutation.

Hypoxia induced by Na2S2O4 increases [Na+]i in mouse glomus cells, an effect depressed by cobalt. Experiments with Na+-selective microelectrodes and voltage-clamping

The intracellular sodium concentration ([Na+]i) and resting potential (Em) of cultured mouse glomus cells (clustered and isolated) were simultaneously measured with intracellular Na+-sensitive and conventional, KCl-filled, microelectrodes. Results obtained in clustered and isolated cells were similar. During normoxia (PO2 122 Torr), [Na+]i was 12-13 mM corresponding to a Na+ equilibrium potential (ENa) of about 58 mV. Em was about -42 mV. Hypoxia, induced by Na2S2O4 1 mM (PO2 10 Torr), depolarized the cells by about 20 mV, [Na+]i increased by 21 mM and ENa dropped to about 35 mV. One millimolar of CoCl2 depressed, or blocked, the effects of Na2S2O4 on [Na+]i but did not affect hypoxic depolarization. Voltage-clamping at -70 mV, while delivering pulses of different amplitudes, produced only small (about 10 pA) and slow TTX-insensitive inward currents. Fast and large (TTX-sensitive) inward currents were not detected. The cell conductance (measured with voltage ramps) was less than 1 nS. It was not affected by hypoxia but was depressed by cobalt. Voltage ramps elicited small inward currents in control and hypoxic solutions that were much smaller than those induced by barium (presumably enhancing calcium currents). Also, normoxic and hypoxic currents had lower thresholds and their troughs were at more negative voltages than in the presence of Ba2+. All currents were blocked by 1 mM CoCl2 suggesting that, at this concentration, cobalt exerted a nonspecific effect on glomus membrane channels. Hypoxia induced a large [Na+]i increase (presumably through inflow), but very small voltage-gated inward currents. Thus, Na+ increases (inflow) probably occurred by disturbing a Na+/K+ exchange mechanism and not by activation of voltage-gated channels.

Intrinsic differences in L-selectin expression levels affect T and B lymphocyte subset-specific recirculation pathways

Lymphocyte migration into lymphoid organs is regulated by tissue-specific adhesion molecules such as L-selectin and the alpha4beta7 integrin. Whether L-selectin also regulates lymphocyte subset-specific migration into specific lymphoid tissues was examined in this study by comparing the migration of CD4+ T cells, CD8+ T cells, and B cells from L-selectin-deficient and wild-type mice. T cells were the predominant lymphocyte subset entering PLN, MLN, Peyer's patches, and spleen during short term (1-h) migration assays. However, both B cell and CD4+ and CD8+ T cell entries into PLN, MLN, and Peyer's patches were dramatically impaired (73-98%) by loss of L-selectin. Lymphocyte expression of alpha4beta7 integrin did not compensate for the loss of L-selectin, since both B and T cells predominantly migrated into the spleen in the absence of L-selectin. The more efficient migration of T cells into peripheral lymphoid tissues relative to that of B cells was partly explained by the finding that T cells expressed L-selectin at 50 to 100% higher levels than B cells. In addition, a 50% reduction in L-selectin expression by lymphocytes from hemizygous L-selectin(+/-) mice resulted in a 50 to 70% decrease in short term lymphocyte migration into peripheral lymphoid tissues relative to that of wild-type lymphocytes. Thus, the differential migration of T and B lymphocyte subsets to lymphoid tissues is regulated in part by subset-specific differences in L-selectin expression levels.

8-(N,N-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate reduced [Ca2+]i elevation induced by histamine, serotonin, and glutamate in cultured calf basilar artery smooth muscle cells

AIM

To study the effects of 8-(N,N-diethylamino)-n-octyl-3,4,5- trimethoxybenzoate (TMB-8) on intracellular free calcium ([Ca2+]i) in cultured calf basilar artery smooth muscle cells.

METHODS

[Ca2+]i was examined by a system of measurement of AR-CM-MIC, using Fura 2-AM as a fluorescent indicator.

RESULTS

In the presence of extracellular Ca2+ 1.3 mmol.L-1, histamine (His), serotonin (5-HT), and sodium glutamate (Glu) markedly increased the [Ca2+]i which was attenuated by TMB-8. In Ca2+ free Hanks' solution containing egtazic acid 0.1 mmol.L-1, TMB-8 not only reduced the resting [Ca2+]i, but also inhibited the elevation of [Ca2+]i evoked by His and 5-HT.

CONCLUSION

TMB-8 reduced the resting [Ca2+]i and attenuated His-, 5-HT-, and Glu-induced increases of [Ca2+]i in basilar artery smooth muscle cells.

Sprint training attenuates myocyte hypertrophy and improves Ca2+ homeostasis in postinfarction myocytes

Myocytes isolated from rat hearts 3 wk after myocardial infarction (MI) had decreased Na+/Ca2+ exchange currents (I Na/Ca; 3 Na+ out:1 Ca2+ in) and sarcoplasmic reticulum (SR)-releasable Ca2+ contents. These defects in Ca2+ regulation may contribute to abnormal contractility in MI myocytes. Because exercise training elicits positive adaptations in cardiac contractile function and myocardial Ca2+ regulation, the present study examined whether 6-8 wk of high-intensity sprint training (HIST) would ameliorate some of the cellular maladaptations observed in post-MI rats with limited exercise activity (Sed). In MI rats, HIST did not affect citrate synthase activities of plantaris muscles but significantly increased the percentage of cardiac alpha-myosin heavy chain (MHC) isoforms (57.2 +/- 1.9 vs. 49.3 +/- 3.5 in MI-HIST vs. MI-Sed, respectively; P < or = 0.05). At the single myocyte level, HIST attenuated cellular hypertrophy observed post-MI, as evidenced by reductions in cell lengths (112 +/- 4 vs. 130 +/- 5 micrograms in MI-HIST vs. MI-Sed, respectively; P < or = 0.005) and cell capacitances (212 +/- 8 vs. 242 +/- 9 pF in MI-HIST vs. MI-Sed, respectively; P < or = 0.015). Reverse I Na/Ca was significantly lower (P < or = 0.0001) in myocytes from MI-Sed rats compared with those from rats that were sham operated and sedentary. HIST significantly increased reverse I Na/Ca (P < or = 0.05) without affecting the amount of Na+/Ca2+ exchangers (detected by immunoblotting) in MI myocytes. SR-releasable Ca2+ content, as estimated by integrating forward I Na/Ca during caffeine-induced SR Ca2+ release, was also significantly increased (P < or = 0.02) by HIST in MI myocytes. We conclude that the enhanced cardiac output and stroke volume in post-MI rats subjected to HIST are mediated, at least in part, by reversal of cellular maladaptations post-MI.

Specific expression in mouse mesoderm- and neural crest-derived tissues of a human PDGFRA promoter/lacZ transgene

The platelet-derived growth factor alpha-receptor (PDGFR-alpha) displays a lineage-specific expression pattern in the mouse embryo and is required for normal development of mesoderm and cephalic neural crest derivatives. The purpose of the present study was to demonstrate the in vivo promoter function of genomic DNA fragments representing the 5'-flanking part of the human PDGFRA gene. 2.2, 0.9 and 0.4 kb PDGFRA promoter fragments, ligated to a lacZ reporter gene, were microinjected into fertilized mouse eggs and transgenic mouse lines were established. The expression patterns were basically similar in the 2.2 and 0.9 kb lines and overlapped grossly the endogenous Pdgfra gene expression pattern. The transgenic line with the highest expression level was chosen for detailed analysis. Expression was, as expected, mainly confined to tissues of mesodermal and neural crest origin. No expression was found in epithelial tissues of endo- or ectodermal origin. The promoter fragments were also active in neuroepithelium and in certain neuronal cell types that did not faithfully express PDGFR-alpha mRNA, while they failed to specify reporter expression in PDGFR-alpha expressing O-2A progenitor cells and other glial elements of the central nervous system. Thus, the isolated human PDGFRA promoter contains most but not all of the regulatory elements that are necessary to establish tissue specific gene expression during development.

[8-(N,N-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate(TMB-8) reduced the elevation of [Ca2+]i induced by BHQ, NE and KCl in cultured single smooth muscle cells of the calf basilar artery]

The effect of 8-(N, N-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate (TMB-8) on the elevation of [Ca2+]i induced by 2, 5-di (tert-butyl)-1, 4-benzohydroquinone (BHQ), norepinephrine (NE), KCl in cultured single smooth muscle cells of the calf basilar artery was studied by a system of measurement of AR-CM-MIC, using Fura-2/AM as a fluoresent indicator. In the presence of extracellular Ca2+ 1.3 mmol.L-1, the resting [Ca2+]i was not changed by TMB-8 (10, 30 and 100 mumol.L-1), but the elevation of [Ca2+]i induced by BHQ, NE and KCl were reduced by TMB-8 (30 mumol.L-1) significantly. In Ca2+ free Hank's solution containing EGTA 0.1 mmol.L-1, the resting [Ca2+]i was markedly reduced by TMB-8 (10, 30 and 100 mumol.L-1), and the increase of [Ca2+]i evoked by BHQ and NE was blocked completely by TMB-8 (30 mumol.L-1). The result suggested that TMB-8 inhibited the Ca2+ release from intracellular stores or increased the up-take of Ca2+ into sarcoplasmic reticulum and the inhibition of Ca(2+)-influx from extracellular site may be an indirect machanism.

[Effect of TMB-8 on the increase of intracellular free Ca2+ induced by NE and BHQ in dissociated single rat brain cell]

The inhibitory effect and mechanism of 8-(N, N'-diethylamino) octyl 3, 4, 5-trimethoxybenzoate hydrochloride (TMB-8) on the elevation of single intracellular free Ca2+ concentration ([Ca2+]i) induced by High K+, Norepinephrine(NE) and 2, 5-Di(tert-butyl)-1, 4-benzohydroquinone (BHQ) in dissociated single rat brain cells were studied. The changes of [Ca2+]i were reflected by the fluorescent indicator, Fura-2/AM, employed. In the absence of extracellular Ca2+, Ca-free Hank's solution, preincubation with TMB-8 (10, 30 mumol.L-1) for 20 min significantly decreased the resting [Ca2+]i from 79 +/- 13 nmol.L-1 to 65 +/- 11 and 61 +/- 6 nmol.L-1, respectively. [Ca2+]i were markedly increased by NE and BHQ and reduced significantly to control level by TMB-8. On the other hand, when the cells were incubated in Hank's solution containing Ca2+ 1.3 mmol.L-1, TMB-8(30, 100 mumol.L-1) suppressed the increase of [Ca2+]i induced by NE (0.0001-0.1 mumol.L-1). TMB-8 showed no significant effect on [Ca2+]i elevation induced by KCl and BHQ in Hank's solution containing Ca2+ 1.3 mmol.L-1. These results indicate that TMB-8 reduced [Ca2+]i via increase of the sarcoplasmic reticulum (SR) sequestration, which blocked the release of intracellular store from the SR. However, the inhibitory effect of TMB-8 on Ca-influx from extracellular medium seems to be an indirect action from the saturation of SR with calcium.

Phosphoenolpyruvate carboxylase protein kinase from soybean root nodules: partial purification, characterization, and up/down-regulation by photosynthate supply from the shoots

Phosphoenolpyruvate carboxylase (PEPC) kinase was partially purified about 3000-fold from soybean root nodules by a fast-protein liquid chromatography protocol. This protein-serine kinase has an apparent native molecular mass of about 30,000 as estimated by size-exclusion chromatography. Following electrophoresis of this partially purified PEPC-kinase preparation in a denaturing gel containing dephospho maize leaf PEPC as substrate, the in situ renaturation and assay of protein kinase activity revealed two, PEPC-dependent kinase polypeptides with molecular masses of about 32 and 37 kDa. The approximately 32-kDa polypeptide was significantly more active than the approximately 37-kDa catalytic subunit. The activity of this partially purified PEPC kinase, and a less purified sample, was Ca2+-insensitive. This protein kinase preparation was able to phosphorylate purified PEPCs from soybean nodules, maize leaves, and a sorghum recombinant C4 PEPC. In contrast, this PEPC kinase was unable to phosphorylate a phosphorylation-site mutant form of sorghum C4 PEPC (S8Y), two other soybean nodule phosphoproteins [nodulin-26 and nodulin-100 (sucrose synthase)], bovine serum albumin, and histone III-S. Following in vitro phosphorylation of purified dephospho soybean nodule PEPC from stem-girdled plants by the partially purified nodule PEPC kinase, the former's activity and sensitivity to L-malate inhibition increased and decreased, respectively. Notably, the Ca2+-independent PEPC kinase activity in nodules from illuminated plants was markedly greater than that in nodules harvested from plants subjected to stem girdling or prolonged darkness. Furthermore, the kinase activity in nodules was controlled reversibly by illumination and extended darkness pretreatments of the parent plants, suggesting that photosynthate supply from the shoots is likely responsible for these striking changes in PEPC kinase activity observed in planta in the legume nodule.

Seryl-phosphorylation of soybean nodule sucrose synthase (nodulin-100) by a Ca2+-dependent protein kinase

Sucrose synthase (SS; EC 2.4.1.13) was radiolabeled in situ by incubating detached soybean nodules with 32Pi. Phosphoamino acid analysis indicated that SS was phosphorylated on a serine residue(s). In-vitro phosphorylation of purified nodule SS by desalted nodule extracts was Ca2+-dependent. This SS-kinase was partially purified (approximately 2200-fold) from nodules harvested from illuminated plants. The molecular mass of the SS-kinase was about 55,000 on a Superdex 75 size-exclusion column or in a denaturing autophosphorylation gel. With either purified nodule SS or Syntide 2 as substrate, exogenous calmodulin and phosphatidylserine showed little or no effect on the in-vitro activity of this partially purified protein kinase. However, its activity was inhibited by W-7. The purified nodule SS-kinase (or CDPK) phosphorylated nodule PEP carboxylase (PEPC; EC 4.1.1.31) in the presence of Ca2+. In contrast, a partially purified nodule PEPC-kinase preparation was incapable of phosphorylating nodule SS. Unlike nodule PEPC [Zhang et al. (1995) Plant Physiol. 108, 1561-1568], the phosphorylation state of SS is not likely modulated in planta by photosynthate supply from the shoots.

Modulation of calcium channels in human erythroblasts by erythropoietin

Erythropoietin (Epo) induces a dose-dependent increase in intracellular free Ca2+ ([Ca2+]i) in human erythroblasts, which is dependent on extracellular Ca2+ and blocked by high doses of nifedipine or Ni2+. In addition, pretreatment of human erythroblasts with mouse antihuman erythropoietin receptor antibody but not mouse immunopure IgG blocked the Epo-induced [Ca2+]i increase, indicating the specificity of the Ca2+ response to Epo stimulation. In this study, the erythropoietin-regulated calcium channel was identified by single channel recordings. Use of conventional whole cell patch-clamp failed to detect Epo-induced whole cell Ca2+ current. To minimize washout of cytosolic constituents, we next used nystatin perforated patch, but did not find any Epo-induced whole cell Ca2+ current. Using Ba2+ (30 mmol/L) as charge carrier in cell-attached patches, we detected single channels with unitary conductance of 3.2 pS, reversal potential of +72 mV, and whose unitary current (at +10 mV) increased monotonically with increasing Ba2+ concentrations. Channel open probability did not appreciably change over the voltage range (-50 to +30 mV) tested. Epo (2 U/mL) increased both mean open time (from 4.27 +/- 0.75 to 11.15 +/- 1.80 ms) and open probability (from 0.26 +/- 0.06 to 2.56 +/- 0.59%) of this Ba(2+)-permeable channel. Our data strongly support the conclusion that the Epo-induced [Ca2+]i increase in human erythroblasts is mediated via Ca2+ entry through a voltage-independent Ca2+ channel.

[Urinary tract infections in patients with diabetes mellitus and related factors]

We investigated the results of urine culture between the mid-urine and the bladder puncture urine in 30 cases of diabetes millitus. The results showed that female elderly NIDDM and the patients with diabetic retionopathy, nephropathy and neuropathy had higher incidence of urinary infections. When the leukocyte count in routine urine examination was more than 10 increases/HP, the incidence of urinary infection was higher. The urine culture with bladder puncture was more reliable than midurine. In addition, the nuring care for prevention of the urinary infection in diabetes was dicussed.

Na+/Ca2+ exchange currents and SR Ca2+ contents in postinfarction myocytes

Myocytes isolated from rat hearts 3 wk after myocardial infarction (MI) had lower peak cytosolic free Ca2+ concentration ([Ca2+]i) and reduced maximal extent of cell shortening during contraction, but Ca2+ entry via L-type Ca2+ channels was normal. In the current study using whole cell patch-clamp technique, reverse Na+/Ca2+ exchange current (INa/Ca; 3 Na+ out:1 Ca2+ in) was measured in myocytes in which Na+, K+, and Ca2+ currents were blocked or minimized. Steady-state outward currents measured under these conditions increased with depolarization or with elevation of extracellular Ca2+ concentration ([Ca2+]o) from 1.8 to 5.0 mM, but were inhibited by 5 mM Ni2+ or by reduction of [Ca2+]i to near zero. In addition, reduction of cytosolic free Na+ concentration or of [Ca2+]i also decreased the amplitude of the outward current. These characteristics indicate the outward current was INa/Ca operating in reverse mode. Reverse INa/Ca was significantly lower in MI myocytes, especially at more positive voltages. In addition, sarcoplasmic reticulum (SR)-releasable Ca2+ content as estimated by integrating forward INa/Ca during caffeine-induced SR Ca2+ release was also significantly lower in MI myocytes. Depressed Na+/Ca2+ exchange activity may contribute to abnormal [Ca2+]i dynamics in MI myocytes.

HIV-specific cellular and humoral immune responses in primary HIV infection

Primary human immunodeficiency virus (HIV) infection is characterized by a high-titer viremia that declines precipitously within weeks, most likely as a result of host immune responses. Peripheral blood mononuclear cells (PBMCs) and plasma of four recently HIV-infected individuals were examined to assess the humoral and cellular immune responses potentially involved in early suppression of viral replication. Neutralizing antibodies against autologous viral isolates were low or undetectable in three subjects studied. Cellular cytotoxicity was assayed using Epstein-Barr virus (EBV)-transformed B lymphoblastoid cell lines (B-LCLs) infected with recombinant vaccinia that express HIV-1 proteins. HIV envelope-specific cytotoxicity, which was not mediated by CD8+ cells nor human leukocyte antigen (HLA) class I restricted, developed in PBMCs of all four subjects early after primary infection, but was not correlated with declines in viremia. Gag-specific cytotoxic T lymphocyte (CTL) activity was observed in freshly isolated PBMCs of two subjects, and HIV-specific CTL cell lines were cultured from PBMCs of three subjects shortly after HIV infection. Antibody-dependent cellular cytotoxicity (ADCC) developed early in all four subjects, and was temporally correlated with declines in viremia in two subjects in whom viral load was well characterized. These data suggest that both CTL responses and ADCC may be critical to control of viral replication in acute HIV infection.

Human seminal plasma inhibits brain nitric oxide synthase activity

Nitric oxide is a chemical messenger which functions as a neurotransmitter or as a cytotoxic agent. Nitric oxide synthase (NOS) has been isolated from various mammalian reproductive tissues. The presence or absence of NOS in spermatozoa has not yet been reported. We therefore tested human and murine spermatozoa for NOS activity by measuring the conversion of arginine to citrulline. No activity was found either in human or in murine spermatozoa. Human native semen and human seminal plasma exerted an inhibition on brain NOS activity, as assayed on rat brain cytosolic fractions. This inhibitory effect was dependent on the amount of protein present in the human seminal plasma. No inhibitory effect was observed when homogenates of washed spermatozoa were tested. The human seminal plasma did not affect the Michaelis constant (Km) of NOS for L-arginine (endogenous NOS substrate) whereas the maximal velocity (Vmax) was reduced, suggesting that it contains a non-competitive inhibitor of brain NOS. This inhibitory component was virtually insensitive to heat; a 10 min treatment to 95 degrees C only slightly reduced its ability to inhibit brain NOS. The physiological relevance of our observations remains to be elucidated. Human seminal plasma may exert an inhibition of nitric oxide synthesis on cells other than spermatozoa or on cells from the male or female genital tract, modulating directly or indirectly (via modulation of reactive oxygen species formation) the functional state of the spermatozoa.

[Clinical study on treatment of chemo- or radiotherapy induced leukopenia with fuzheng compound]

The therapeutic effect of Fuzhen Compound, a Chinese herbal medicine, on leukocyte count in 59 patients with cancer of advanced stage after chemo-or radiotherapy were observed. Among 41 cases with leukopenia before treatment, leukocyte of 37 cases were normalized after treatment, the count pre-and post-treatment were (2.8 +/- 0.6) x 10(9)/L and (5.9 +/- 1.4) x 10(9)/L respectively (P < 0.01). In 18 patients with normal leukocyte count before treatment, the counts of 17 cases were still kept in normal after treatment. The time for leukcoyte recovering was 8.0 days in average, while that of 23 patients did not take Fuzhen Compound was 20.6 +/- 1.8 days. The results indicated that the Fuzhen Compound could alleviate the inhibition of chemo-or radiotherapy on hemopoietic function of bone marrow and has leukocytogenic effect.

Calcium currents in postinfarction rat cardiac myocytes

Myocytes isolated from rat hearts that have suffered 35% myocardial infarction (MI) 3 wk prior have lower peak cytosolic Ca2+ concentration ([Ca2+]i) during contraction compared with Sham myocytes, a difference that is amplified by isoproterenol or high extracellular Ca2+ concentration ([Ca2+]o). To evaluate whether reduced [Ca2+]i in MI myocytes is due to decreased Ca2+ entry, we measured [3H]PN-200-110 [dihydropyridine (DHP)] binding and whole cell Ca2+ current (ICa). DHP binding decreased in both sarcolemmal vesicles and intact myocytes from hearts 3 wk after MI. In contrast, ICa was not different between Sham and MI myocytes incubated at 1.8 mM [Ca2+]o. At 5.0 mM [Ca2+]o, ICa increased similarly in Sham and MI myocytes. Steady-state voltage dependence of activation and inactivation were similar between Sham and MI myocytes, as were the fast- and slow-inactivation time constants. Isoproterenol (1 microM) significantly increased ICa in Sham but not in MI myocytes. Forskolin (10 microM) dibutyryl adenosine 3',5'-cyclic monophosphate (5 mM) significantly increased ICa in MI myocytes; the magnitude of ICa increase was similar to that observed in Sham myocytes. We conclude that 1) decreased systolic [Ca2+]i in MI myocytes was not due to reduced Ca2+ entry via L-type Ca2+ channels; 2) discrepancy between DHP binding (decrease) and ICa (no change) results may be explained by higher channel availability and/or increased long-opening modes (mode 2) in MI myocytes; 3) reduction in isoproterenol-induced [Ca2+]i increase in MI myocytes was partly due to decreased ICa, resulting in less Ca2+ release from sarcoplasmic reticulum; 4) the adenylate cyclase-protein kinase A signal-transduction pathway functioned normally in MI myocytes; and 5) decreased beta-adrenergic responsiveness in MI myocytes was likely due to altered coupling by G proteins.

HIV-regulated diphtheria toxin A chain gene confers long-term protection against HIV type 1 infection in the human promonocytic cell line U937

Gene therapy approaches have recently been investigated for the treatment of acquired immunodeficiency syndrome (AIDS), both in preclinical and clinical studies, because more traditional antiviral agents have proven to be of limited effectiveness. We have previously shown that long-term protection against both laboratory and clinical isolates of human immunodeficiency virus type 1 (HIV-1) was conferred by HIV-regulated diphtheria toxin A (DT-A) chain in a human T cell line. Because the monocyte/macrophage cell is an important reservoir for HIV-1 in infected individuals, we sought here to determine whether HIV-regulated DT-A would also be effective in the promonocytic cell line U937. We report here that long-term protection, conferred by HIV-regulated DT-A, was observed in U937 cells, but that protection was dependent on the stock of HIV IIIB used for challenge. HIV production was measured by p24 assays, polymerase chain reaction (PCR) for HIV vif, gag, and reverse transcriptase (RT) sequences, and cocultivation with peripheral blood mononuclear cells (PBMCs). Complete protection was seen in DT-A-transduced cells with a stock of IIIB propagated on H9 cells and titered on peripheral blood mononuclear cells (PBMCs), while protection in these same cells with a second stock of IIIB, propagated and titered on H9 cells, was only partial and dose dependent.

[The prevention and treatment of oral cavity ulcer and infection of patients with oral cavity malignant cancer after chemotherapy]

44 oral cavity malignant cancer patients who underwent operation and chemotherapy are taken as the Experiment Group,using a mixture liquid of Calcii Folinas and Gentamycin to rinse out the mouth.48 patients using single drug gargle as the Comparison Group,The comparison between the two gargles' effects on oral ulcer and infection shows that the incidence of oral ulcer in the Comparison Group(P<0.05),and there is a significant difference.The oral infection incidence is lower too (P>0.05).There is no statistical difference.The expeiment suggests that gargling with mixture liquid is superior to using single drug liquid.

[Ca2+]i transients in hypertensive and postinfarction myocytes

Changes in intracellular calcium concentration ([Ca2+]i) in paced fura 2-loaded myocytes isolated from Sham, renovascular hypertensive (Hyp), and myocardial-infarcted (MI) rats were examined. Compared with controls, Hyp myocytes paced at physiological rates had similar systolic but elevated diastolic [Ca2+]i. By contrast, systolic [Ca2+]i was significantly lower and diastolic [Ca2+]i higher in MI myocytes. The different patterns of alterations in [Ca2+]i dynamics in Hyp and MI myocytes may partly explain predominantly diastolic dysfunction in hypertensive hearts and systolic dysfunction in hearts surviving MI. In the presence of 1 microM isoproterenol, both Hyp and MI myocytes had much lower systolic [Ca2+]i when compared with their respective controls. Isoproterenol restored the elevated diastolic [Ca2+]i in Hyp myocytes toward normal but had no effect on the intrinsic differences in diastolic [Ca2+]i between Sham and MI myocytes. The observation that isoproterenol lowers diastolic [Ca2+]i in Hyp myocytes toward normal may provide a cellular mechanism for the lack of efficacy of beta-adrenergic blockers to improve diastolic compliance in patients with hypertensive hypertrophic cardiomyopathy.

Plant regeneration from rice (Oryza sativa L.) embryogenic suspension cells cryopreserved by vitrification

Rice cells were precultured for 10 d in medium containing 60 g/L sucrose and subsequently for 1 d in medium supplemented with 0. 4 M sorbitol. After loading with 25%PVS2 at 22°C for 10 min and dehydration in 100%PVS2 at 0°C for 7. 5 min,they were plunged into liquid nitrogen directly. Survival was 45. 0 ±5.1% (based on the reduction of triphenyl tetrazolium chloride)following warming and unloading. For regrowth, cells were plated on semi-solid medium replenished with 40%(w/v) starch for 2d prior to reculture. Cell suspensions were reestablished and plants were regenerated from recovered cells. Twenty eight plants set seeds in the greenhouse.

Effects of hypoxia on the intracellular K+ of clustered and isolated glomus cells of mice and rats

Carotid bodies of rats and mice were used to measure the intracellular potassium activity, ai(K), of clustered and isolated glomus cells normally oxygenated (pO2 102-139 Torr), and during hypoxia (pO2 2-82 Torr) induced by Na-dithionite. ai(K) was measured with intracellular ion-selective microelectrodes, and the resting potential (EM) with KCl-filled micropipettes. Under normoxia, the ai(K) of clustered cells in both species was higher than that of isolated cells. This resulted in more negative potassium equilibrium potentials (EK's). There was no correlation between ai(K) and EM in clustered cells, but this correlation was significant in isolated cells. Hypoxia significantly decreased ai(K) in clustered and single mouse cells, and in clustered rat cells, although its effects on single rat cells were variable. ai(K) decreases were accompanied by cell depolarization and positive shifts in EK. During hypoxia, there were significant correlations between ai(K) and EM in all cells. It is suggested that ai(K) did not influence the EM of clustered cells under normoxia because of interference by K+ pumping mechanisms toward glomus cells from surrounding sustentacular processes. This hindrance is not present when glomus cells are isolated. During hypoxia K+ pumping from sustentacular cells is disrupted, allowing the EM of clustered glomus cells to follow their ai(K) and behave like isolated cells. The different effects of hypoxia on isolated rat and mouse cells may be due to activation of different types of glomus cells.

[An experimental investigation on preventive measures of skin ulcers induced by extravascular mitomycin C]

In order to make an investigation on skin ulcer induced by Mitomycin C extravasation, the preventive measures were undergone by the following ex-periment. A subcutaneous ulcerative model induced by 0.1mg Mitomycin C (MMC) extravasation in the leg of BALA/C mice was established. On the model subject, 8 pharmacologic adjuvants or physical modulation were adopted. It is preferential to choose local injection with 0.1 ml 99% dimethyl sulfoxide (DMSO), or with additional smearing DMSO on the affected skin. 10 days later, the ulcerative areas with DMSO treatment were significantly decreased in contrast with 0.1 ml 0.9% NaCI treatment (P < 0.001). The other preferential treatment were in turn by the injection of 0.1 ml 5% NaHCO3 (P < 0.001); 0.1 ml 1% procainamidi hydrochloridum (including 0.4% dexame-thasonum) (P < 0.001) or smearing with 0.1 ml 90% DMSO (including 10% Vit E) (P < 0.01). Delayed application of DMSO after MMC extravasation 30 min had been proven the limited effects on the prevention of ulcer (P < 0.05). Neither cooling of skin or local injection of sodium thiosulfate reduced MMC ulceration (P > 0.05). The mechanisms of prevention of MMC extravascular ulcer by DMSO or 5% NaHCO3 were briefly discussed.

Factors predicting outcome in 215 consecutive thawed embryo replacements

This retrospective study was undertaken to determine which factors were associated with outcome in thawed embryo replacement cycles. The number of embryos replaced and the response to exogenous ovarian stimulation in the original IVF cycle were significantly associated with the conception rate.

[Immunoelectron microscopic studies on the process of tumor cytolysis mediated by lymphokine activated NK cells]

The second fraction (F2) cells isolated from PBL by discontinuous Percoll density gradient centrifugation were used as the enriched natural killer (NK) cells. After being incubated with rIL2, the activated F2 cells (F2 LAK) acquired the cytolytic ability upon NK resistant tumor cell lines. In F2 LAK, about 45% of the cells were CD16+, therefore F2 LAK were used as the enriched CD16+LAK cells (or lymphokine activated NK cells). The cytolysis process of lung adenocarcinoma LTEPa-2 or K562 tumor cells mediated by CD16+LAK cells were investigated with colloidal gold labelled Ab via scanning and transmission immunoelectron microscopy. The results showed that the CD16+LAK cells extended their protrusions deep into the target cells. Crypts of various diameter and depth were observed on the surface of the target cells with membrane injury at the bottom of the crypts. It was found that the cytoplasmic granules and vacuoles of CD16+LAK cells were concentrated in the area close to the E-T conjugated side, and sometimes the granules were found within the LAK protrusions. The attacked target cells died by apoptosis and necrosis. This study provided direct evidence that lymphokine activated NK cells are effectors of LAK cells.

[The change in dynamics of cell proliferation cycle by passive smoking in fetal rabbit]

An animal model of IUGR was induced in rabbit by passive smoking. The dynamics of cell proliferation cycle in fetal brain, liver and placenta was analysed by flow cytometry. The results showed that the ratio of cell number in phase G0+G1 to the total number of cells in all phases was increased, while the cell number in phase S+G2M to the total cell number of all phases was decreased. It means that the proliferation of fetal cell and placenta was inhibited significantly. The actual inhibition was occurred in the phase of transformation from phase G1 to S.

[Assay of plasma amino acid concentration in maternal and growth-retarded fetuses caused by passive smoking in rabbits]

Rabbits were exposed to cigarette smoking in: (1) Group A: everyday exposure in the whole period of pregnancy (n = 9); (2) Group B: everyday exposure in the late half period of pregnancy (n = 7); (3) Group C: non-smoking (n = 7). The results showed that the fetal rabbits in group A had combined symmetric and asymmetric IUGR, Group B asymmetric IUGR. The maternal plasma total amino acid concentration in both experimental groups is not different significantly to that of the control group. All the essential amino acid concentrations were lower, some of the nonessential amino acid were lower and some were higher than that of the control group. The fetus in both experimental groups had significantly lower plasma concentrations of total amino acid and most of the essential and nonessential amino acids when compared with that of the control group. This was mainly because of a reduction of the branched chain amino acids lysine, phenylalanine, methionine, isoleucine, leucine, valine, serine, glutamine, alanine, tyrosine and histidine. Fetal plasma amino acid concentrations decreased more significantly than that of the maternal's and most of fetal/maternal amino acid concentration ratios in both experimental group were lower than that of the control group.

[The application of frozen homogenic brephobone in surgical treatment of chronic periapical periodontitis]

Clinical effectiveness of frozen homogenic brephobone as a filling material in the treatment in the treatment of chronic periapical periodontitis was evaluated.42 patents with chronic periapical periodontitis,periapical,cyst and periapical granuloma were observed.After apical curettage was performed,22 cases were filled with frozen homogenic brephobone and other cases were close bone cavity with traditional treatment.All these cases were then covered with periodontal packing agent.Radiograph and clinical observation were made respectively at 2 week,1 month,3 month,6 month and 12 month recall visit following the surgery.It was found that the way of filling with frozen homogenic brephobone is more advantageous than the traditional way.

Comparative studies on the inhibitory effects of calcium antagonists on cytosolic Ca2+ levels increased by high-potassium or glutamate in cultured rat cerebellar granule cells

The inhibitory effects of calcium antagonists on high-potassium or glutamate (Glu) enhanced intracellular calcium ion ([Ca2+]i) levels were studied in cultured cerebellar granule cells. Dosages between 0.5 and 10 microM of flunarizine, nicardipine, SM6586 and SM12565 reduced the rise in [Ca2+]i induced by 50 mM KCl in a dose-dependent manner, although diltiazem, verapamil and nifedipine showed less effects on such [Ca2+]i increases. SM6586, SM12565 and flunarizine at dosages below 10 microM each reduced the magnitude of the [Ca2+]i increase induced by 25 microM Glu, but the other examined calcium antagonists were less effective. These results suggest the dissimilar efficacy of calcium antagonists on the inhibition of [Ca2+]i levels increased by high-potassium and Glu.

Live computerized videomicroscopy of cerebral microvessels in brain slices

A model system for studying cerebral microvasculature is presented in which submerged in vitro brain slices are examined by computerized videomicroscopy. Brain slices are superfused continuously with artificial cerebrospinal fluid, while blood vessels are monitored using a transmission light microscope with water immersion objectives. The responses to well-characterized vasoactive compounds indicate that basic physiological characteristics are maintained in this preparation. This model system represents a simple and rapid technique for studying cerebrovascular responses under conditions in which vessels are surrounded by their normal cellular microenvironment. An additional advantage of this technique is the ability to perform simultaneous electrophysiological recordings in identified neurons. This will facilitate the study of interactions between neuronal and vascular elements and may help elucidate mechanisms underlying the local regulation of cerebral microvasculature.

[Changes in serum folic acid and vitamin B12 levels in liver cirrhosis and its clinical significance]

The levels of serum folic acid and vitamin B12 were determined in 40 cases of liver cirrhosis with radioimmunoassay. It was shown that in 87.5% of the patients folic acid level was lower than that of a control group and in 67.5% serum vitamin B12 level was higher than that of the control group (P less than 0.05). The correlation between liver cirrhosis and dysbolism of folic acid and vitamin B12 and the megaloblastic changes and clinical significance were discussed.

Human T lymphotropic virus types I- and II-specific antibody-dependent cellular cytotoxicity: strain specificity and epitope mapping

Antibody-dependent cellular cytotoxicity (ADCC) against human T lymphotropic virus (HTLV) types I and II was investigated using sera obtained from infected individuals or from rabbits immunized with HTLV-I or -II envelope peptides. Target cells included an HTLV-I-transformed cell line (C91/PL), an HTLV-II-transformed cell line (729pH6neo), and Epstein Barr virus (EBV)-transformed B lymphocytes expressing HTLV-I or -II env or gag gene products after infection with vaccinia/HTLV recombinants. ADCC activity was directed at HTLV-I and -II envelope glycoproteins but not against core (gag) components. In contrast to the human immunodeficiency virus system, significant cross-reactivity between HTLV-I- and -II-directed ADCC activity was observed. Epitope mapping studies using sera from rabbits that had been immunized with HTLV-I or -II envelope peptides suggested that the critical epitopes for ADCC activity are located primarily in hydrophilic regions of the exterior (gp46) part of the envelope glycoprotein.

Delineation of type-specific regions on the envelope glycoproteins of human T cell leukemia viruses

Two different approaches were used to map the type-specific regions on human T cell leukemia virus (HTLV) envelope glycoproteins. 1) Antibody reactivities of polymerase chain reaction-confirmed HTLV-I or HTLV-II carriers' sera were analyzed by Western blot assay with seven recombinant proteins containing different regions of HTLV-I or HTLV-II envelope proteins. 2) Rabbit antibodies elicited by nine HTLV-I Env synthetic peptides were used to react with the native HTLV envelope glycoproteins in an antibody-dependent cellular cytotoxicity (ADCC) assay. The results of the Western blot analysis showed that RP-B2, which contains amino acid residues 166 to 213 from HTLV-II exterior glycoprotein, was specifically reactive with 90.6% (48 of 53) of the HTLV-II carriers' sera but not with any of the HTLV-I carriers' serum (0 of 71). In contrast, RP-B, which contains amino acid residues 166 to 229 from HTLV-I exterior glycoprotein, was reactive with 85.1% (114 of 134) of the HTLV-I carriers' sera but not with any HTLV-II carrier serum (0 of 62). Furthermore, anti-HTLV-I Env synthetic peptide antibody-mediated ADCC identified several distinguishing HTLV-I ADCC epitopes in the middle region (amino acid residues 177 to 257) of the HTLV-I exterior glycoprotein. Therefore, HTLV type-specific epitopes reside mainly in a 69-amino acid sequence bounded by two cysteine residues (amino acids 157 and 225 for HTLV-I and 153 and 221 for HTLV-II), in the middle region of the exterior envelope glycoproteins.

Delineation of type-specific regions on the envelope glycoproteins of human T cell leukemia viruses

Two different approaches were used to map the type-specific regions on human T cell leukemia virus (HTLV) envelope glycoproteins. 1) Antibody reactivities of polymerase chain reaction-confirmed HTLV-I or HTLV-II carriers' sera were analyzed by Western blot assay with seven recombinant proteins containing different regions of HTLV-I or HTLV-II envelope proteins. 2) Rabbit antibodies elicited by nine HTLV-I Env synthetic peptides were used to react with the native HTLV envelope glycoproteins in an antibody-dependent cellular cytotoxicity (ADCC) assay. The results of the Western blot analysis showed that RP-B2, which contains amino acid residues 166 to 213 from HTLV-II exterior glycoprotein, was specifically reactive with 90.6% (48 of 53) of the HTLV-II carriers' sera but not with any of the HTLV-I carriers' serum (0 of 71). In contrast, RP-B, which contains amino acid residues 166 to 229 from HTLV-I exterior glycoprotein, was reactive with 85.1% (114 of 134) of the HTLV-I carriers' sera but not with any HTLV-II carrier serum (0 of 62). Furthermore, anti-HTLV-I Env synthetic peptide antibody-mediated ADCC identified several distinguishing HTLV-I ADCC epitopes in the middle region (amino acid residues 177 to 257) of the HTLV-I exterior glycoprotein. Therefore, HTLV type-specific epitopes reside mainly in a 69-amino acid sequence bounded by two cysteine residues (amino acids 157 and 225 for HTLV-I and 153 and 221 for HTLV-II), in the middle region of the exterior envelope glycoproteins.

[Observations of neurobehavior in lead exposed workers]

A neurobehavioral test of lead-exposed workers and the correlations between test scores and certain biochemical indices was made. The results showed that the scores of digit span, mental arithmetic, block design, digit symbol, Santa-Ana dexterity, Benton visual retention and pursuit aiming of lead-exposed workers tests were significantly lower than those of control groups. The scores of Santa-Ana dexterity, block design and digit span tests of lead-exposed workers were highly negatively correlated with levels of ZPP in blood.

Damaging role of neutrophil elastase in the elastic fiber and basement membrane in human emphysematous lung

The immunolocalization of human neutrophil elastase (HNE) in the alveolar interstitium of 6 patients with emphysema was investigated by immunochemical electron microscopy. The results showed that HNE is localized in the azurophil granules of neutrophils, and extracellularly on the elastic fibers of alveolar interstitium and basement membranes of epithelium and endothelium. The damage of elastic fibers and basement membranes could be observed. The HNE level of the alveolar interstitium was obviously elevated and closely related to the severity of emphysematous lesions as shown by measuring the mean linear intercept (MLI) in 4 emphysematous lungs with chronic bronchitis (r = 0.84). This suggests that HNE might play an important role in the pathogenesis of emphysema. Although enlarged airspace and increased MLI data were observed in 2 patients, one with asthma and the other, an elderly patient, without lung diseases, the HNE level of alveolar interstitium is much less than that of the other 4 chronic obstructive pulmonary disease patients. This implies that the mechanism of the the airspace enlargement occurring in the 2 patients may be different from that of others. These findings support the hypothesis of elastase-antielastase imbalance on the pathogenesis of pulmonary emphysema.

[A pathological study of finished-cement pneumoconiosis: report of 3 autopsy cases]

Three autopsy cases exposed only to finished-cement dusts were studied. Pathologic changes relevant to cement dusts in the lungs were similar, including distribution of numerous dust macules and focal emphysema formed in the parenchyma of lungs. Additionally, "cement bodies" were obtained in the dust macules. By means of electron diapensive X-ray analysis (EDXA), EDXA-SEM (scanning electron microscopy) and X-ray diffraction, the elements of dust foci and digested concentrates of the lungs were measured, and the morphology of dust granules was studied. Results indicated that the elements of intrapulmonary dusts were just the same as those of finished-cement dusts. Therefore, the pulmonary lesions obtained were considered to be induced by finished-cement dusts.

Effects of oral ciclosporin on acute and chronic murine cytomegalovirus infection

Mice fed a basal diet which contained 0.018% ciclosporin (CsA) achieved immunosuppressive blood levels of 1,400-2,200 ng/ml. Observations for 84 days of mice placed on this diet and infected at the same time with murine cytomegalovirus (MCMV) showed elevated virus titers and more widespread infection of various organs. An enhancing effect on acute MCMV infection measured by virus titers in the spleen 5 days after infection was evident only after 14 days of prior CsA ingestion. In groups of mice which were already infected with virus for 14 or 21 days, 14 days of CsA ingestion was needed before enhanced MCMV titers were noted in organs tested. Pretreatment with CsA of donor mice, which provided MCMV-specific immune spleen cells in passive protective experiments, eliminated the protective effect of transferred cells for recipient mice challenged with MCMV. These results suggest that CsA enhanced virus titers and helped maintain chronic persistent infection in certain organs by affecting the development or function of immune cells. Regardless of whether CsA was given before or after virus infection, about 2 weeks of CsA administration was required before elevation of virus titer was observed.