Comparison of immune responses in mice after transfusions from single or multiple H-2 donors.
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Animals↗
Biomedical subjects
S Joseph
Publications and source records attributed to S Joseph.
Differential effects of the diacylglycerol kinase inhibitor R59022 on thrombin versus collagen-induced human platelet secretion.
R59022 is an inhibitor of the enzyme 1,2-diacylglycerol (DAG) kinase, which, by inhibiting the conversion of DAG to phosphatidic acid, causes an increase in endogenous DAG levels and the activity of the DAG-dependent enzyme protein kinase C. This property of the drug was utilized in the present study to assess the role of DAG, i.e., its relative importance as a potentiatory versus inhibitory mediator, in agonist-induced platelet activation. The phosphorylation of the 40-47-kDa protein by protein kinase C was monitored as an indicator of endogenous DAG levels and correlated with other agonist-induced platelet responses such as platelet aggregation, 5-hydroxytryptamine (5HT) secretion and arachidonate release, the agonists used being those that induce DAG formation, e.g., thrombin and collagen. Pretreatment of platelets with R59022 before agonist addition resulted in the potentiation of 5HT secretion as well as 45 kDa protein phosphorylation induced by thrombin and the DAG analogue, 1,2-dioctanoylglycerol (DiC8). However, collagen-induced 5HT secretion was significantly inhibited (70%) in the presence of R59022, which also had strong inhibitory effects on aggregation induced by collagen, as well as by thrombin and DiC8. The inhibition of collagen-induced secretion by R59022 was in contrast to the potentiatory effects of DiC8 on the same, suggesting that even although DAG acts as a potentiatory signal in this system, the inhibitory effects of R59022 on collagen-induced aggregation can mask any effects of endogenous DAG. This inhibitory effect of R59022 on agonist-induced platelet aggregation makes it unsuitable as a tool in studying the role of DAG in platelet activation induced by agonists such as collagen as well as the 'weak' agonists (ADP, adrenaline and platelet-activating factor), where aggregation mediates other responses such as arachidonate release and secretion. Furthermore, potentiatory effects of R59022 on 5HT secretion induced by phorbol 12-myristate 13-acetate and ionomycin, which are effects unlikely to be related to inhibition of DAG kinase was observed, and these effects further underline the non-specificity in the actions of R59022 and its limitations as a tool in studying platelet stimulus-response coupling.
Arachidonic Acid↗
Production in vitro of antibodies directed against alloantigen-specific recognition sites on T cells and on lymphocytotoxic HLA antibodies.
We have examined the mechanism of immunological unresponsiveness in a recipient (P.S.) with a long-term functioning renal allograft. P.S., whose HLA type is A1, A30; B14, B18; DR1, w8; DRw52; DQw1 and in whose serum we had earlier demonstrated the presence of antiidiotypic antibodies, received a kidney from a cadaver donor of HLA type A1, A10, B8 in March, 1970. Peripheral blood B lymphocytes from the patient were transformed with Epstein-Barr virus (EBV), and by the cluster-picking technique a B cell line was propagated with continuous production of antibodies. Antiidiotypic antibodies with two distinct biological functions were demonstrable; one specifically inhibiting the lymphocytotoxic activity of anti-HLA-B8, B5, and DR3 reference typing sera, and the other specifically inhibiting proliferative responses in MLC of the recipient's lymphocytes and of third party cells sharing B14, DR1, DQw1 with the patient against stimulator cells carrying B8, DR3 antigens. Immunodepletion experiments demonstrated that the inhibitory activity was associated with the IgM fraction. Absorption experiments suggested that different antibodies may be responsible for the inhibition of lymphocytotoxic activity of anti-HLA sera and of the proliferative responses in MLC. Antiidiotypic antibodies have been postulated to be important in maintaining allograft tolerance in vivo, thereby enhancing renal allograft survival. The availability of such antibodies in large quantities, produced in vitro, could provide antisera for the immunochemical characterization of specific idiotypic receptors on immunoglobulins and T lymphocytes.
Antibody Specificity↗
Nitrous oxide analgesia: partial antagonism by naloxone and total reversal after periaqueductal gray lesions in the rat.
Analgesia induced by nitrous oxide was examined using radiant heat tail flick and electrical evoked foot flick tests in rats. Rats exposed to 80 and 60% nitrous oxide expressed statistically significant elevations of percent analgesia (% MPE) compared to air exposed rats. Rats exposed to 30% nitrous oxide showed no significant difference in percent analgesia. Pretreatment with naloxone (10 mg/kg s.c.) produced a significant decrease in %MPE and an increase in variance of response after exposures to 80% nitrous oxide in a double blind study. Kainic acid lesions of the ventral and caudal periaqueductal grey (PAG) reversed analgesia produced by 80% nitrous oxide in a crossover blink study compared to saline lesions. In conclusion, this evidence suggests that the caudal-PAG-raphe mangus-dorsal horn pain inhibition pathway is in part involved in the analgesia induced by nitrous oxide.
Analgesics↗
1,2-Dioctanoylglycerol but not 1-oleoyl-2-acetylglycerol inhibits agonist-induced platelet responses. Dependence of effects on extent of 45-kDa protein phosphorylation and agonist type.
1. The effect of the membrane-permeable diacylglycerol analogues, 1,2-dioctanoylglycerol (Oco2Gro) and 1-oleoyl-2-acetyl-glycerol (OleAcGro) on agonist-induced platelet activation processes were compared with those of the phorbol ester, phorbol 12-myristate 13-acetate (PMA), using appropriately labelled washed human platelets. 2. Pre-treatment (10-300 s) with Oco2Gro (15-60 microM) or PMA (16 nM) before addition of thrombin (0.2 U/ml) or, addition of these agents 10-20 s after thrombin, resulted in a significant reduction (20-80%) in the extent of thrombin-induced intracellular Ca2+ ([Ca2+]i) mobilisation and arachidonate/thromboxane B2 release. OleAcGro (62-125 microM) had no effect on thrombin-induced [Ca2+]i elevations but had a slight (15%) inhibitory effect on thrombin-induced arachidonate release with a 5-min pre-incubation. Addition of Oco2Gro, PMA or OleAcGro on their own caused no rise in [Ca2+]i levels or arachidonate release. 3. Collagen (20 micrograms/ml) induced substantial arachidonate release without a detectable rise in [Ca2+]i. Pretreatment (10-300 s) with Oco2Gro (15-60 microM), PMA (16 nM) or OleAcGro (62 microM) before collagen addition or addition of these agents 30-60 s after collagen addition resulted in a significant potentiation of arachidonate release (1.2--2-fold over control), even though thromboxane B2 formation in response to collagen was inhibited in the presence of Oco2Gro or PMA. 4. Both Oco2Gro and PMA had dual effects on 5-hydroxytryptamine secretion induced by thrombin or collagen. Short pre-incubations (less than 2 min) with these agents caused a potentiation of sub-maximal agonist-induced secretion, while not affecting secretion induced by maximal agonist concentrations. With longer pre-incubation times (5-15 min) however, a significant reduction in the level of agonist-induced secretion in the presence of Oco2Gro or PMA was observed. Inhibition of secretion was also observed in platelets treated with indomethacin (10 microM), suggesting that inhibition of thromboxane B2 formation alone does not account for inhibition of 5-hydroxytryptamine secretion. OleAcGro had no inhibitory effects on agonist-induced secretion even though it potentiated it (with less than 2-min incubations) at sub-maximal agonist concentrations. 5. Time courses of phosphorylation of a 45-kDa protein, a marker of protein kinase C activation, in 32P-labelled platelets showed that while Oco2Gro (60 microM) and PMA (16 nM) caused a 4--5-fold increase in 32P-labelling of this protein over a 5-min incubation period, OleAcGro (62-125 microM) caused a 1.5-fold increase in labelling which was only maintained for a 10--30-s period.(ABSTRACT TRUNCATED AT 400 WORDS)
Blood Platelets↗
Effect of the polyamine-spermine on agonist-induced human platelet activation--specific inhibition of "aggregation-independent" events induced by thrombin, but not by collagen, thromboxane mimetic, phorbol ester or calcium ionophore.
Spermine, a naturally occurring polyamine, has previously been described as an inhibitor of purified phospholipase C and protein kinase C in cell-free systems. The present study examines the effect of spermine on platelet aggregation, dense-granule secretion and thromboxane (Tx) B2 synthesis induced by a variety of agonists, which cause the activation of one or both enzymes to different extents. These studies revealed that, while spermine (10 mM) inhibited platelet aggregation in response to all the agonists examined, [14C]-5-hydroxytryptamine (5HT) release and TxB2 synthesis induced by thrombin (0.2 U/ml) and collagen (10-40 micrograms/ml) alone, were inhibited by spermine, the percentage inhibition being greater than 90% for both responses with thrombin, 30% for 5HT release and 80% for TxB2 synthesis with collagen. The inhibition of collagen-induced [14C]-5HT secretion by spermine was due entirely to the inhibition of aggregation-dependent TxA2 synthesis as addition of a sub-threshold concentration of U46619, which induced no secretion on its own, totally restored collagen-induced [14C]-5HT secretion to the levels seen in the absence of spermine. Moreover, collagen-induced TxB2 formation in unstirred platelets, which occurred independently of aggregation was not significantly affected by spermine (10 mM). However, the inhibition of maximal thrombin-induced [14C]-5HT secretion and TxB2 synthesis, which are both aggregation-independent phenomena, could be attributed to the inhibition of thrombin-induced diacylglycerol formation and intracellular calcium mobilization, which were both inhibited by 80% in the presence of spermine.(ABSTRACT TRUNCATED AT 250 WORDS)
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
Effect of phorbol 12-myristate 13-acetate (PMA) on agonist-induced arachidonate release and 5-hydroxytryptamine secretion in human platelets. Dependence of effects on agonist type and time of incubation with PMA.
We have previously demonstrated synergistic potentiation of secretion by phorbol 12-myristate 13-acetate (PMA) and platelet agonists such as thrombin and the thromboxane mimetic, U46619, with short (less than 2 min) pre-incubations of PMA, despite inhibition of agonist-induced [Ca2+]i mobilization and arachidonate/thromboxane release. In this study, the effect of PMA on 5-hydroxytryptamine secretion in relation to arachidonate/thromboxane B2 release induced by collagen as well as the 'weak agonists', ADP, adrenaline and platelet-activating factor (PAF), was investigated using human platelet-rich plasma. Short incubations (10-30 s) with PMA (400 nM) before agonist addition caused an inhibition (60-100%) of 5-hydroxy[14C]tryptamine secretion and thromboxane B2 formation in response to maximally effective doses of ADP (10 microM), adrenaline (10 microM) and PAF (0.5 microM) but potentiated collagen-induced 5-hydroxy[14C]tryptamine secretion and [3H]arachidonate/thromboxane release. However, a longer pre-incubation with PMA (5 min) caused a significant reduction (20-50%) in the extent of collagen-induced 5-hydroxy[14C]tryptamine secretion and thromboxane B2 formation as seen earlier with thrombin, although collagen-induced [3]arachidonate release was still unaffected. Pretreatment of platelets with the cyclo-oxygenase inhibitor, indomethacin (10 microM), abolished 5-hydroxy[14C]tryptamine secretion in response to the weak agonists and reduced collagen (2.5-10 micrograms/ml) -induced secretion by 50-90%, depending on the collagen concentration. Addition of PMA (400 nM) 10 s before these agonists in indomethacin-treated platelets resulted in synergistic interactions between agonist and PMA leading to enhanced 5-hydroxy[14C]tryptamine secretion, although this was notably less than the synergism observed previously between thrombin and PMA or U46619 and PMA. The results suggest that the effect of short incubations with PMA on 5-hydroxytryptamine secretion induced by 'thromboxane-dependent' agonists, such as those examined in this study, is determined by the effect on agonist-induced thromboxane synthesis. However, when endogenous thromboxane synthesis is blocked, weak agonists as well as collagen can synergize with PMA at potentiating 5-hydroxytryptamine secretion, albeit to a weaker extent than thrombin or U46619. The results also suggest that PMA has differential effects on arachidonate release induced by collagen and thrombin.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
Dexamethasone suppression test in schizophrenic patients: report from India.
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Dexamethasone↗
MLC-inhibiting serum in mice after transfusion with 3 M KCl-extracted soluble antigen.
Balb/c (H-2d) mice were transfused weekly with 3 M KCl-extracted soluble antigen prepared from splenocytes of C3H/HeJ (C3H)(H-3k) mice. One week after each transfusion, spleen and serum samples were collected from transfused mice and pooled. The serum was absorbed with erythrocytes and spleen cells from C3H mice and heat inactivated. Spleen cells from transfused mice were tested for proliferative responses in mixed lymphocyte culture (MLC) against stimulator cells from the antigen donor C3H or from third party SJL (H-2s) mice. The proliferative responses of lymphocytes from soluble-antigen-transfused Balb/c mice to stimulator cells from C3H and SJL mice were not suppressed. Furthermore, suppressor cells could not be demonstrated in spleens of transfused mice in in vitro coculture experiments. The MLC inhibition test was utilized to investigate the presence of MLC-inhibiting serum from transfused mice. The results demonstrate that serum capable of inhibiting responses of Balb/c mice were induced after three weekly injections of soluble antigen and that this inhibition in MLC was specific for the stimulator cells from the antigen donor C3H mice. These findings differ from our studies using whole blood transfusions where (1) MLC inhibiting antibodies developed in Balb/c mice after only one transfusion of C3H whole blood, and (2) serum from blood transfused mice achieve greater inhibition than soluble-antigen-induced serum. These results suggest that although soluble antigen is capable of inducing MLC inhibiting serum, the kinetics of this induction may be different from transfusion with whole blood.
Animals↗
Suppressor cells and anti-idiotypic antibodies in mice transfused with 3M KCl-extracted soluble antigen.
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Animals↗
Anti-idiotypic antibodies and suppressor cells in patients receiving pretransplant donor-specific blood transfusions.
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Blood Transfusion↗
The blood transfusion effect: characterization of T cell alloantigen-specific receptors by sera from transfused mice.
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Animals↗
Synergistic potentiation of 5-hydroxytryptamine secretion by platelet agonists and phorbol myristate acetate despite inhibition of agonist-induced arachidonate/thromboxane and beta-thromboglobulin release and Ca2+ mobilization by phorbol myristate acetate.
Previous studies have demonstrated an inhibition of agonist-induced inositol phospholipid breakdown and intracellular Ca2+ ([Ca2+]i) mobilization by phorbol esters in platelets. In this study, we have examined the effect of phorbol 12-myristate 13-acetate (PMA) on agonist-induced granule secretion and correlated it with agonist-induced [Ca2+]i mobilization, arachidonate and thromboxane (Tx) release in human platelets. With increasing times of incubation with PMA (10 s-5 min), the rise in [Ca2+]i induced by thrombin and the TxA2 mimetic, U46619, was increasingly inhibited (90-100% with 5 min incubation) and, correlating with this, thrombin-induced [3H]arachidonate, TxB2 and beta-thromboglobulin (beta TG) release were also inhibited. In addition, the conversion of exogenously added arachidonate to TxB2 was inhibited (50-80%) by a 10 s-5 min pretreatment with PMA. However, secretion of 5-hydroxy[14C]tryptamine (5HT) induced by thrombin or U46619 was not inhibited by 10 s-2 min incubations with PMA and, on the contrary, with low agonist concentrations, was potentiated by PMA in the absence of a significant rise in [Ca2+]i or endogenous Tx formation, to levels significantly greater than or equal to the sum of that obtained when agonist and PMA were added separately. With longer times of incubation with PMA (5 min), these synergistic effects became less pronounced as inhibitory effects of PMA on agonist-induced [14C]5HT secretion became apparent. The results indicate that, while PMA may cause an inhibition of agonist-induced [Ca2+]i mobilization resulting in an inhibition of agonist-induced arachidonate, TxB2 and beta TG release, its effects on agonist-induced 5HT secretion may be complicated by [Ca2+]i-independent synergistic effects of agonist and PMA.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
MLC-inhibiting antibodies in mice after blood transfusions.
Balb/c (H-2d) mice were transfused weekly with 0.1 ml of whole blood from C3H/HeJ (C3H) (H-2k) mice. One and two weeks after each transfusion, mice were bled and the sera were collected and pooled. Serum samples from transfused mice were absorbed with erythrocytes and spleen cells from C3H mice, and then heat-inactivated. The presence of antiidiotypic antibodies in these sera was investigated using the mixed lymphocyte culture (MLC) inhibition test, in which spleen cells from normal Balb/c mice were tested for proliferative responses to x-irradiated C3H stimulator cells in the presence of sera from transfused mice. Sera obtained from transfused mice caused significant inhibition of responses in MLC. This inhibition in MLC was specific for stimulator cells from the blood donor (C3H), and little or no inhibition was observed with stimulator cells from third-party SJL mice. In addition, the inhibitory effect in MLC was specific for responder cells from the recipient Balb/c mice and no inhibition was observed with responder cells from blood donor C3H mice. These results suggest that blood transfusions induce antiidiotypic antibodies that can block the T cell antigen-specific receptors and cause inhibition of responses of the recipient mice to blood donor alloantigens in MLC. Thus in this strain combination, disparate for the entire H-2 region, antiidiotypic antibodies developed after 1 blood transfusion. These findings are in contrast to our earlier published results in which antiidiotypic antibodies developed after 3 transfusions in recipient-blood donor combination incompatible for the K and I regions. These data suggest that the development of antiidiotypic antibodies may be related to the level of histoincompatibility at the H-2 complex between recipient and the blood donor.
Animals↗
Induction of antiidiotypic antibodies by blood transfusions. Characterization of T cell alloantigen-specific receptors by sera from transfused mice.
Balb/c (H-2d) mice were transfused weekly with 0.1 ml of whole blood from C3H (H-2k) mice. One week after 3 blood transfusions (BT), the mice were bled and the sera collected and pooled. The 3BT serum was absorbed twice with C3H lymphocytes and IgG isolated by ion-exchange chromatography. Balb/c anti-C3H, Balb/c anti-Balb/c, and Balb/c anti-SJL (H-2s) lymphocytes were generated in the mixed lymphocyte cultures and metabolically labeled with 35S-methionine. Cell lysates were prepared from labeled lymphocytes and precleared by absorption with normal mouse serum. Immunoprecipitation was carried out by 3BT-IgG and NMS-IgG. 3BT-IgG specifically precipitated 7 molecules (30K, 60K, 72K, 86K, 92K, 97K, 145K) from Balb/c anti-C3H lymphocytes. In contrast, 3BT-IgG did not precipitate these molecules from Balb/c anti-Balb/c or from Balb/c anti-SJL lymphocytes. The data suggest that BT induces antibodies directed against the blood donor alloantigen-specific receptors on recipient's T lymphocytes.
Animals↗
Positive and negative subtypes of schizophrenia. A study from India.
Ninety-eight schizophrenic patients were studied to examine the concept of positive and negative subtyping. Using a cross-sectional phenomenological approach, the relationship of this subtyping with six definitions of schizophrenia was also investigated. The study provides support for this subtyping. Principal components analysis of the data and correlational structure of positive and negative symptom complexes lend further support to this notion.
Adult↗
Lactobezoar in a low-birth-weight neonate.
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Bezoars↗
Physiological acclimatization to heat after a spell of cold conditioning in tropical subjects.
The effects of brief spells of cold conditioning on heat acclimatized tropical subjects on the decay and reacclimatization status to heat were evaluated on 12 Indian male infantry soldiers in the cooler months at Delhi. After 8 d of heat acclimatization in a climatic chamber maintained at 45 degrees C dry bulb (Tdb) and 30% relative humidity (rh), the subjects were conditioned to cold for 21 d by exposing them to a temperature of 10 degrees C daily for 4 h. During the cold conditioning phase the subjects had no access to either heat exposure or strenuous work. The cold conditioning was followed by reacclimatization to heat. Significant loss in heat acclimatization status was observed, both in terms of exercise oral temperature and heart rate. The loss in status after 1 d reinduction to heat acclimatization was in the range of 45-56%. However, within 3 d all of the subjects once again regained the full acclimatization status. The cold conditioning did not alter the sweat output during the reinduction to heat phase.
Acclimatization↗