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Biomedical subjects

S E Calvano

Publications and source records attributed to S E Calvano.

At least 55 records · Page 3Linked to original sources
PubMed1990

Pathophysiologic glucocorticoid elevations promote bacterial translocation after thermal injury.

Thermal injury results in transient elevations of plasma glucocorticoids and promotes translocation of bacteria from the gut to the mesenteric lymph nodes (MLN) in rats. Translocated organisms are quickly cleared following uncomplicated thermal injury. However, subsequent burn wound infection, in temporal association with sustained pathophysiologic elevations of plasma corticosterone, results in the continued presence of enteric bacteria in the MLN. To study the role of sustained pathophysiologic steroid elevations in the mediation of this prolonged bacterial translocation, Wistar rats were randomly placed in groups receiving one of the following: (i) a 30% total body surface area scald injury with placement of a subcutaneous corticosterone pellet, (ii) a 30% total body surface area scald and a sham pellet implantation, (iii) a sham burn and a corticosterone pellet implantation, or (iv) a sham burn and a sham pellet implantation. The animals were sacrificed on days 1 and 4 after injury, and cultures of the MLN, as well as the liver and spleen, were taken. Implantation of corticosterone pellets resulted in sustained elevations of plasma corticosterone compared with controls not receiving corticosterone pellets, similar to results seen in association with injury and infection. These pathophysiologic elevations were associated with the prolonged presence of organisms in the MLN (90% of burned rats with implanted corticosterone pellets versus 25% of rats with uncomplicated burns on postburn day 4; P less than 0.01), but only in the presence of burn injury. Pathophysiologic glucocorticoid elevations did not lead to progression of translocation to the viscera or blood. Thus, the pathophysiologic glucocorticoid response contributes to the translocation of enteric bacteria and their prolonged presence in the MLN after systemic injury.

Animals↗
PubMed1990

The acute splanchnic and peripheral tissue metabolic response to endotoxin in humans.

The in vivo alterations in organ-specific substrate processing and endogenous mediator production induced by endotoxin were investigated in healthy volunteers. An endotoxin bolus (20 U/kg) produced increased energy expenditure, hyperglycemia, hypoaminoacidemia, and an increase in circulating free fatty acids. These changes included increased peripheral lactate and free fatty acid output, along with increased peripheral uptake of glucose. Coordinately, there were increased splanchnic uptake of oxygen, lactate, amino acids, and free fatty acids, and increased splanchnic glucose output. There were no changes in circulating glucagon, or insulin and transient changes in epinephrine and cortisol were insufficient to explain the metabolic changes. Plasma cachectin levels peaked 90 min after the endotoxin infusion, and hepatic venous (HV) cachectin levels (peak 250 +/- 50 pg/ml) were consistently higher than arterial levels (peak 130 +/- 30 pg/ml, P less than 0.05 vs. HV). No interleukin 1 alpha or 1 beta was detected in the circulation. Circulating interleukin 6, measured by B.9 hybridoma proliferation, peaked 2 h after the endotoxin challenge (arterial, 16 +/- 2 U/ml; HV, 21 +/- 3 U/ml). The net cachectin efflux (approximately 7 micrograms) from the splanchnic organs demonstrates that these tissues are a major site for production of this cytokine. Hence, splanchnic tissues are likely influenced in a paracrine fashion by regional cachectin production and may also serve as a significant source for systemic appearance of this cytokine.

Adult↗
PubMed1990

Serum cachectin/tumor necrosis factor in critically ill patients with burns correlates with infection and mortality.

Serum cachectin/tumor necrosis factor (TNF), a cytokine implicated in the pathogenesis of septic shock, may appear in the circulation during serious infection, but the frequency of detection of elevated serum levels during protracted critical burn injury is unknown. Serial serum samples taken from 43 critically ill patients with burns with and without sepsis were analyzed for TNF using an enzyme-linked immunosorbent assay (ELISA). TNF was detectable (greater than 34 picograms per milliliter) at one or more time points in 69 per cent of the patients with sepsis versus 33 per cent of those without sepsis, in 71 per cent of the patients who died versus only 31 per cent of the survivors and in only one healthy normal control patient (n = 21). The frequency of the appearance of TNF correlated with both infection and mortality rate. Moreover, all three patients with TNF levels greater than 540 picograms per milliliter died. Neither the size of the burn nor injury from inhalation correlated with detection of TNF. A subset of 16 patients was studied longitudinally from admission until resolution of injury and these data demonstrate that TNF appears transiently and repetitively in the circulation of patients during infection and protracted critical burn injury. Also, serum cortisol levels were significantly higher during sepsis and death in the absence of serum TNF, compared with sepsis and death with detectable cachectin, suggesting that cortisol may interact with the production or detection of this cytokine during ongoing infection and lethal injury. In this study, we have demonstrated that serum TNF is detectable with greater frequency and in higher concentration in patients with sepsis and in those who ultimately succumb to the burn injury, that serum TNF appears transiently and repetitively in the circulation during injury and that higher serum cortisol levels are correlated with the absence of serum TNF during sepsis and lethal injury.

Burns↗
PubMed1989

Cachectin/tumor necrosis factor production by fetal and newborn rat hepatic macrophages.

The capacity of fetal and newborn hepatic macrophages to produce cachectin/tumor necrosis factor (TNF) has not been previously examined. The role that TNF plays in newborn infection is also unknown. In the present report, fetal and newborn rat hepatic macrophages have been maintained in short-term tissue culture, and are shown to produce TNF in response to in-vitro endotoxin stimulation. Cells obtained are morphologically and antigenically consistent with macrophages, and are depleted of accessory cells and lymphocytes. In response to increasing doses of endotoxin, fetal and newborn hepatic macrophages produce TNF, and this production is suppressed fully by pretreatment with dexamethasone. The results demonstrate that fetal and newborn hepatic macrophages possess the capability to produce TNF in vitro. We propose that TNF may play a role in the response of the fetus and newborn to bacterial infection.

Animals↗
PubMed1989

Changes in lymphocyte number and phenotype in seven lymphoid compartments after thermal injury.

Thermal injury is associated with dysfunction of host defense systems. The present study used flow cytometric immunofluorescence analyses to investigate changes in number and phenotype of lymphocytes in seven different lymphoid compartments at 2, 6, 12, 24, 48, and 60 days after 50% total body-surface area thermal injury in the rat. Relative to sham-injured control rats, at postburn day 2, significant lymphopenia was observed in the peripheral blood along with depletion of lymphocytes from the spleen and thymus. By day 6 after injury, lymphocytes in the bone marrow and cervical lymph nodes decreased significantly while numbers in the spleen and thymus remained depressed. Splenic and cervical node lymphocyte numbers normalized by day 12, the bone marrow and thymus numbers still were significantly lower than control, and a 6.5-fold increase in number of lymphocytes was observed in the nodes draining the burn wound, pooled axillary, brachial, inguinal, and lumbar lymph nodes. At day 24 after injury, the thymus and bone marrow virtually were depleted of lymphocytes, the mesenteric lymph nodes manifested a significant decrease, and lymphocytes in the nodes draining the burn wound continued to increase in number. This same pattern was maintained on day 48, but numbers of lymphocytes in the mesenteric nodes normalized. At day 60 after injury, lymphocyte numbers in all tissues were normalized, but the spleen and nodes draining the burn wound where increased numbers compared to control persisted. Cell-surface phenotyping was performed on all lymphoid tissues at all time intervals to determine the percentages of lymphocytes comprising the following subsets: Ia+ cells (B cells and activated T cells), T cells, T-Helper/Inducer cells (T-H/I), and T-Suppressor/Cytotoxic (T-S/C) cells. Although changes in lymphocyte subset percentages were complex, they could be divided grossly into two phases. First, all compartments showed significant phenotypic changes in the first six days after burn. With the exception of the nodes draining the burn wound and the blood, this was followed by a return towards normal on day 12. The second phase then ensued with significant phenotypic changes again occurring in most tissues from days 24 to 60 after injury. These studies demonstrate that burn injury results in dramatic alterations in lymphocyte numbers and subset percentages in different lymphoid compartments. Immune alterations observed following thermal injury may be due, in part, to a redistribution of the cellular elements responsible for generation of the immune response.

Animals↗
PubMed1989

Peripheral blood leukocyte kinetics following in vivo lipopolysaccharide (LPS) administration to normal human subjects. Influence of elicited hormones and cytokines.

Lipopolysaccharide (LPS, endotoxin) administration to human subjects elicits significant elevations in plasma cachectin/TNF, epinephrine, and cortisol. This study examined the temporal relationship between changes in blood leukocyte subsets and plasma mediators following endotoxin administration to normal human subjects. A five-minute intravenous infusion of purified LPS (20 units/kg Escherichia coli) was administered to 12 healthy volunteers. Blood samples were obtained at varying intervals after infusion and analyzed for differential cell counts and lymphocyte subsets (CD2, CD3, CD4, CD8, CD20, and HLA-DR) by flow microfluorimetry, and also assayed for plasma cachectin/TNF, epinephrine, and cortisol. Plasma cachectin/TNF was significantly elevated at 75 and 90 minutes after infusion with a peak concentration of 261 +/- 115 pg/ml noted 75 minutes after infusion. A significant plasma epinephrine elevation of 181 +/- 75 pg/ml was demonstrated one hour after infusion, while significant elevations in plasma cortisol were noted from one to five hours after infusion with a peak level of 34 +/- 3 micrograms/dl three hours after infusion. A profound monocytopenia (p less than 0.01) was noted one hour after infusion. Temporally associated with the rise in plasma cortisol was a reversal of the early granulocytopenia to a significant granulocytosis (p less than 0.01 versus preinfusion mean), whereas a marked lymphocytopenia (p less than 0.01) was observed from one to six hours after infusion. During the period of hypercortisolemia, CD2, CD3, and CD4 lymphocyte percentages were decreased (p less than 0.01) while CD20 and HLA-DR lymphocyte percentages were increased (p less than 0.01). There was a small percentage decrease in CD8 lymphocytes from one to 24 hours after infusion (p less than 0.01), although relative to the one-hour nadir, there was a significant rise in the percentage during the time of elevated plasma cortisol concentrations. A six-hour infusion of epinephrine (30 ng/kg/min) administered to six healthy volunteers resulted in a monocytosis (p less than 0.05) and granulocytosis (p less than 0.01) without a change in lymphocyte number or lymphocyte subset percentage. Previous reports have shown that in vivo corticosteroid infusion causes a prominent granulocytosis, monocytopenia, and lymphocytopenia with a decrease in the percentages of CD3 and CD4 lymphocytes. The peripheral blood leukocyte dynamics documented in the current study are similar to patterns observed following in vivo corticosteroid administration. This study suggests that the acute adrenocortical response to endotoxemia primarily mediates the subsequent changes in leukocyte subsets.

Adult↗
PubMed1988

The decrease in peripheral blood CD4+ T cells following thermal injury in humans can be accounted for by a concomitant decrease in suppressor-inducer CD4+ T cells as assessed using anti-CD45R.

Using single- and two-color fluorescence flow cytometry, 10 thermally injured human subjects were assessed over time for both percentages and absolute numbers of lymphocytes comprising peripheral blood lymphocyte subpopulations. The CD3+ lymphocyte percentage decreased significantly in the early postburn period, and this decrease could be accounted for entirely by a concomitant decrease in the CD4+ lymphocyte percentage. Further, the decline in CD4+ percentage was due to a specific decrease in the suppressor-inducer subset of CD4 as defined using anti-CD45R. No change in the helper-effector subset of CD4 was noted. The percentage of CD8+ lymphocytes did not change significantly at any time postburn nor did subsets of CD8 as defined using anti-CD11. Numerical changes in lymphocyte subsets were dominated by a general lymphopenia occurring on Day 4 following injury. However, suppressor-inducer (CD4+/CD45R+) T cells also decreased significantly on postburn Day 1. These results further elucidate phenotypic changes in immunoregulatory subsets following major injury and suggest a possible basis for depressed autologous mixed lymphocyte responsiveness of burn patient T cells, one of the functional immunologic defects associated with severe injury.

Adult↗
PubMed1988

Monoclonal antibodies directed at human T lymphocyte activation antigens cross react with concanavalin A-stimulated canine and baboon peripheral blood lymphocytes.

A panel of 10 monoclonal antibodies directed at activation antigens on human T lymphocytes were tested for cross reactivity with canine and baboon resting and ConA stimulated peripheral blood lymphocytes. Monoclonal antibodies anti-OKT19, anti-OKT-21, and anti-OKT22 labeled a high percentage of both resting and stimulated canine and baboon cells. Anti-OKT24 labeled activated but not resting baboon lymphocytes and did not label canine lymphocytes. Anti-HLA-DR labeled a small percentage of resting baboon lymphocytes (presumably B cells) and a high percentage of activated baboon and resting and activated canine lymphocytes. Anti-OKT14, anti-OKT20, and anti-OKT23 did not label canine or baboon lymphocytes. Anti-OKT9 did not label baboon lymphocytes, but labeled a low percentage of lymphocytes in one dog. Anti-TAC labeled activated but not resting canine and baboon cells.

Animals↗
PubMed1988

Granulocyte contamination of Ficoll-Hypaque preparations of mononuclear cells following thermal injury may lead to substantial overestimation of lymphocyte recovery.

During ongoing flow cytometric studies of burned patient blood leukocytes, it was noted frequently that large numbers of granulocytes were present along with the mononuclear cells at the plasma/Ficoll-Hypaque (F-H) interface following centrifugation over F-H. Since differential WBC counts are not routinely performed on F-H interface cells, it is possible that many previous immunologic studies of burned patients have greatly overestimated numbers of lymphocytes recovered. The present study sought to quantify the extent to which granulocyte contamination of F-H separated cells occurs following burn injury. Blood from 15 thermally injured patients (7-55% total body surface area burn) was studied serially at 24 hr, 48 hr, and weekly thereafter through 6 weeks postburn (PB). Controls were age-matched normals (No. of control bloods = 59). Three-part differential cell counts (lymphocytes, monocytes, and granulocytes) were performed on both F-H interface cells and RBC-lysed whole blood. Counts were performed by light scatter analysis on a flow cytometer. Except at 48 hr, at every time studied through 4 weeks PB, there was significant contamination of F-H interface cells with granulocytes. At 24 hr PB, 41 +/- 9% of the interface cells were granulocytes while at 4 weeks, PB 24 +/- 8% of the interface cells were granulocytes. The data did not support the interpretation that this increase in F-H interface granulocytes was simply reflective of the granulocytosis commonly observed after burn. Thus artificial generation of granulocytosis by addition of extra normal leukocytes to normal blood resulted in complete separation of granulocytes from mononuclear cells following centrifugation over F-H.(ABSTRACT TRUNCATED AT 250 WORDS)

Burns↗
PubMed1988

Glucocorticoid regulation of enkephalins in cultured rat adrenal medulla.

The effect of dexamethasone on enkephalin-containing (EC) peptide levels and preproenkephalin mRNA levels was determined in adrenal medullary explants (glands) from sham and hypophysectomized (hypox) rats. Culture for 4 days in serum-free medium without dexamethasone resulted in a 13- and 4-fold increase in EC peptide levels in sham and hypox glands, respectively. The addition of dexamethasone (10(-5) M) produced a 20- to 26-fold increase in EC peptides in sham and hypox glands. In serum free medium, hypox glands showed a concentration dependent increase in EC peptides with the ED50 for dexamethasone equal to 5.7 x 10(-7) M. Since the glucocorticoid antagonist RU486 partially blocked the rise in EC peptides in sham glands, it appears that the increase in EC peptides in sham glands in the absence of dexamethasone is a result of a higher concentration of endogenous corticosterone in sham compared to hypox glands. Dexamethasone resulted in a 6-fold increase in preproenkephalin mRNA in hypox glands cultured for 2 days. This increase was approximately proportional to the increase in EC peptides seen at 4 days. In serum free medium progesterone, testosterone, and deoxycorticosterone failed to increase EC peptides in hypox glands. These results indicate that glucocorticoid treatment is required for maximal proenkephalin gene expression and EC peptide biosynthesis in cultured glands.

Adrenal Medulla↗
PubMed1987

Regulation of rat adrenal medullary enkephalins by glucocorticoids.

Opioid peptides and their precursors of the proenkephalin family are found in the chromaffin cells of the rat adrenal medulla in low quantities. However, if the gland is denervated, there is a 10 to 20-fold increase in enkephalin-containing (EC) peptides consisting mostly of the precursor proenkephalin. The denervation-induced rise in medullary EC peptides is blocked by hypophysectomy, and partially reinstated by corticosterone, dexamethasone or ACTH treatment. In the intact rat, intermediate doses of corticosterone or dexamethasone reduce the denervation-induced increase in EC peptides, while a high dose of dexamethasone restores this response. These results indicate that glucocorticoids exert a permissive effect in vivo on the denervation-induced stimulation of EC peptide biosynthesis.

Adrenal Medulla↗
PubMed1987

Investigation of cross-reactivity between commercially available antibodies directed against human, mouse, and rat lymphocyte surface antigens and surface markers on canine cells.

Using automated flow cytometry, 23 commercially available antibodies (all but one of them monoclonal) raised against surface antigens of specific populations of human, rat, and mouse lymphocytes were tested for cross-reactivity to peripheral blood lymphocytes from five clinically healthy adult dogs. Of all the antibodies tested, only the polyclonal anti-asialo GM1 directed against mouse NK cells, and the monoclonal antibodies anti-HLA-DR directed against the human class II antigen and anti-B1, a human pan B cell marker, consistently labeled subpopulations of canine lymphocytes.

Animals↗
PubMed1987

Comparison of numerical and phenotypic leukocyte changes during constant hydrocortisone infusion in normal humans with those in thermally injured patients.

Twenty-four to 48 hours after thermal injury, percentages and number of T X mu or T4 lymphocytes decrease with little or no change in T X gamma or T8 cells. Additionally, the plasma hydrocortisone level is extremely elevated. Since administration of hydrocortisone to normal humans also produces a specific decrease in T X mu or T4 lymphocytes, it was hypothesized that burn induced elevations of hydrocortisone were responsible for the decrease in T X mu/T4 cells. In this study, normal humans were administered constant infusions of hydrocortisone for six hours, such that plasma levels were increased to an extent that mimics those 24 to 48 hours after thermal injury. Before, during and after infusion, percentages and numbers of lymphocytes, monocytes, granulocytes and T3, T4, T8, T11, HLA-DR and Leu7 lymphocytes were quantified by flow cytometry. Results were compared with those for patients with burns. The plasma hydrocortisone level rose to 49.0 micrograms per deciliter during infusion, similar to the mean of 47.5 micrograms per deciliter for patients with burns. Infused volunteers showed significant lymphopenia, monocytopenia and granulocytosis. Additionally, there were significant decreases in percentages of T3, T4 and T11 lymphocytes, no significant changes in percentages of T8 or HLA-DR and an increase in percentages of Leu7+ cells. These changes in lymphocyte subsets mimicked those of burn patients. Numbers of T3, T4 and T11 cells significantly decreased during hydrocortisone infusion while numbers of T8, HLA-DR and Leu7 lymphocytes did not change. Burn patients showed decreased numbers of T3 and T4 cells, but this T3/T4 lymphopenia was not as great as during hydrocortisone infusion. These results support the hypothesis that elevation of hydrocortisone is responsible for the lymphocyte phenotypic changes that occur in the early postburn period.

Adult↗
PubMed1984

Autologous and allogeneic mixed-lymphocyte responses following thermal injury in man: the immunomodulatory effects of interleukin 1, interleukin 2, and a prostaglandin inhibitor, WY-18251.

A group of 30 burn patients with 36-87% total body surface area (TBSA) burns was studied at 24-48 hr postburn. These included studies of (1) autologous and allogeneic mixed-lymphocyte reactions (MLR); (2) the immunoregulatory influence of mitomycin C-treated T cells, non-T cells, and unfractionated peripheral blood lymphocytes (PBL) on allogeneic MLR; and (3) correlation between the proportions of T-cell subsets defined with monoclonal antibodies (OKT4 and OKT8) and autologous MLR. Studies concerning adherent cell production of thromboxane, prostaglandin E2, and prostaglandin F2a and the immunomodulatory effects of Interleukin 1 (IL-1), Interleukin 2 (IL-2), and a prostaglandin inhibitor, WY-18251, on autologous MLR are presented. The autologous mixed-lymphocyte reaction was depressed in 60% of the burn patients tested. This depressed response correlated closely to the extent of third-degree injury (P less than 0.025) and to TBSA injury greater than 60% (P less than 0.025). A linear correlation was observed between the depression in autologous MLR and a decrease in both the percentage of OKT4+ T cells and the OKT4+/OKT8+ ratio. The response of T cells from burn patients in allogeneic MLR was normal. Age, sex, TBSA of the burn, and size of second-degree burn did not correlate with the abnormalities observed in MLR. Mitomycin C-treated mononuclear cells, purified T cells, or non-T cells from burned patients did not demonstrate any suppressive influence on MLR in normals. Monocyte number and arachidonic acid metabolism were investigated. In addition to increased numbers of monocytes following thermal injury, adherent cells produced increased quantities of thromboxane, prostaglandin E2, and prostaglandin F2a. The effects of Interleukin 1, Interleukin 2, and a prostaglandin inhibitor, WY-18251, were studied in autologous MLR (AMLR) of burned and normal patients. Interleukin 1 and WY-18251 did not induce any significant changes in proliferation in burned patients or normal controls. When compared to cultures without exogenous IL-2, an increase in AMLR was observed following the addition of IL-2 to burn patient cultures at Day 6 and Day 7 of culture. Although the addition of IL-2 did increase proliferation in AMLR of normal controls at Day 6 and Day 7, the enhancement observed for the burn patient cultures represented a restoration to the level of normal control cultures without IL-2. A dose-dependent increase in AMLR was observed in T cells isolated from normal and burned patients in the presence of purified Interleukin 2.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

Analysis of the mitogenic effects of toxic shock toxin on human peripheral blood mononuclear cells in vitro.

It has been shown previously that the staphylococcal enterotoxins A and B are T-cell mitogens and also cause inhibition of murine plaque-forming cells generated in vitro. Similarly, toxic shock toxin, a 24,000-MW protein produced by toxic shock-associated strains of Staphylococcus aureus, is mitogenic and inhibits the generation of both murine and rabbit plaque-forming cells. In this study, an analysis of the T-cell response to toxic shock toxin was performed. Human peripheral blood mononuclear cells responded to toxic shock toxin over a broad dosage range (1 ng/ml to 5 micrograms/ml) with maximum proliferation at day 4 (96 hr) of culture. Heat treatment (100 degrees C for 60 min) of toxic shock toxin attenuated its mitogenic effects by only a small amount, and this attenuation could be reversed with increasing concentration of the toxin. By cytofluorography, both untreated and toxic shock toxin-treated small lymphocytes manifested normal percentages of OKT3+, OKT11+, OKT4+, OKT8+, HLA/DR+, and Leu-7+ cells. However, toxic shock toxin-induced blasts were 99% OKT11+ and expressed the receptor for interleukin 2 (89%-100% TAC+). Approximately 85% of the blasts were OKT4+, and 25% of the blasts were OKT8+. Proliferation of purified, double-rosetted T cells was enhanced monotonically by the addition of irradiated "non-T" cells. Irradiated, monocyte-enriched non-T cells were 2.5 times more potent than unfractionated non-T cells in producing quantitatively similar proliferation by toxic shock toxin-stimulated, autologous T cells. In addition, preincubation of non-T cells for 24 hr with toxic shock toxin, followed by extensive washing and irradiation, induced substantial proliferation by unexposed, autologous T cells. These data show that toxic shock toxin is mitogenic for T cells and requires accessory cells for maximal activity. Further, this substance appears to induce both a subset of OKT4+ (Class II MHC-restricted) and OKT8+ (Class I MHC-restricted) blasts.

Antigen-Presenting Cells↗
PubMed1984

Circadian fluctuations in plasma corticosterone, corticosterone-binding activity and total protein in male rats: possible disruption by serial blood sampling.

Male rats were bled serially every 6 h for 48 consecutive hours. Plasma so obtained was assayed for corticosterone (B), corticosterone-binding activity (CBA) and total plasma protein (TPP). Although the averaged data indicated a significant circadian rhythm in plasma B, inspection of the circadian changes in individual animals showed that 40% had irregular or aberrant patterns of plasma B. Additionally, circadian fluctuations in plasma CBA were approximately 3-fold lower in magnitude than previously reported, and there was no significant circadian change in TPP. Running wheel activity during the 48 h blood sampling period decreased by over 50% indicating that the serial sampling procedure caused disruption of the activity cycle. However, the majority of wheel-running activity occurred during the dark portion of the day-night cycle. Because circadian fluctuations in plasma proteins, including corticosteroid binding globulin (CBG), may be directly related to changes in locomotor activity, it is suggested that the attenuation of circadian changes in CBA and TPP were due to disruption of the daily cycle of locomotor activity. The abnormal circadian patterns in plasma B observed in some animals also may have been caused by disruption of the activity cycle in spite of the fact that the rats did not appear to be stressed as evidenced by concentrations of plasma B that were well within the normal range.

Animals↗
PubMed1984

Flow cytometric analysis of lymphocyte subpopulations after thermal injury in human beings.

Several theories have been advanced in an effort to explain immunologic suppression after thermal injury, that is monocyte production of immunoregulatory prostaglandins, activation of suppressor cells, production of suppressive serum factors and alteration in helper cell function. In the current study, cytofluorometric analysis was performed on peripheral blood mononuclear cells isolated from 30 severely burned individuals using a FACS IV cell sorter. Fluorescein labeled monoclonal antibodies were used to phenotype total T cells (OKT3+), helper cells (OKT-4+), suppressor cells (OKT-8+), monocytes (antimono.2+) and B cells (anti-Ia+). After burn injury, the most striking phenotypic alterations observed were a marked decrease in the number and percentage of total OKT3+ T cells and OKT4+ helper cells. No significant increases were observed in the OKT8+ suppressor cell subpopulation. Monocytes exhibited a transitory increase during the first 48 hours postburn which returned to normal by postburn day 7. The percentage of Ia+ cells were either normal or decreased in number during the course of the injury. An OKT-4 to OKT-8 ratio of less than 1.00 at 24 to 48 hours postburn may represent a reliable predictive index for death by sepsis. These data suggest that the syndrome of burn induced immunologic suppression may be better described as a "burn induced immunodeficiency syndrome," that is characterized by decreased numbers or function of Interleukin-2 producing helper cells, or both.

Adult↗