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PubMed2001

Peripheral arterial responses to treadmill exercise among healthy subjects and atherosclerotic patients.

UNLABELLED: BACKGROUND-Peripheral cutaneous vascular beds, such as the fingertips, contain a high concentration of arteriovenous anastomoses, richly innervated by a-adrenergic nerve fibers, to control heat regulation. Nevertheless, for a variety of technical reasons, finger blood flow responses to exercise have not been well studied in health and disease. Hence, we compared finger pulse-wave amplitude (PWA) responses to exercise among 50 normal volunteers and 57 patients with atherosclerotic coronary artery disease (CAD) using a robust, modified form of volume plethysmography. METHODS AND RESULTS: PWA was quantified for each minute of exercise as a ratio relative to baseline. Exercise PWA responses were compared with clinical, hemodynamic, ECG, and myocardial single photon emission computed tomography parameters. Among normal subjects, 38 (76%) manifested vasodilation throughout exercise and 12 (24%) manifested initial vasodilation followed by vasoconstriction at high heart rate thresholds. None manifested vasoconstriction throughout exercise. By contrast, 20 CAD patients (35%) manifested progressive vasoconstriction from the onset of exercise, and 10 others (18%) manifested vasoconstriction at low heart rate thresholds (P < 0.001 versus normals) after initial vasodilation with exercise. Patients exhibiting vasodilation versus vasoconstriction during exercise had similar clinical and exercise profiles, except for a greater use of ACE inhibitors and a greater level of achieved metabolic equivalents among the former (P<0.05 for both). CONCLUSIONS: Half of our CAD patients manifested diminution in PWA that was consistent with peripheral arterial vasoconstriction during the early phases of treadmill exercise. Such paradoxical vasoconstrictive responses were not observed in normal subjects and, therefore, they may represent generalized vascular pathology secondary to atherosclerosis.

Adult↗

PubMed1982

Immunological aspects of psoriasis: V. T. cell subsets and suppressor cell functions regulating immune responses in peripheral blood.

T cell subsets bearing Fc-receptors for either IgG (TG) or IgM (TM), and suppressor cell activity of peripheral blood mononuclear cells on in vitro lymphoproliferative responses were studied in patients with untreated psoriasis. The proportions of TG and TM cells were unmodified in 15 patients compared to 15 control subjects studied in parallel experiments. The concanavalin A-induced suppressor cell activity, as well as the spontaneous suppressor cell function of in vitro short-lived adherent cells, were in the normal range for 7 out of 8 psoriatic patients investigated. The data argue against the possibility that a generalized suppressor cell defect occurs in psoriasis.

Adolescent↗

PubMed1993

Effects of vitamin E and selenium on immune responses of peripheral blood, colostrum, and milk leukocytes of sows.

This study was designed to assess how dietary vitamin E (E) and (or) selenium (Se) concentrations affect immune responses of gestating and peripartum sows. Multiparous sows (24), assigned to one of four groups at breeding, were fed ensiled, shelled corn-soybean meal-based diets without supplemental E or Se (-E-Se), with .3 mg of Se/kg (-E+Se), with 60 IU of E/kg (+E-Se), or with both supplemental E and Se (+E+Se) during gestation and to d 4 of lactation. Blood was obtained on 0, 30, 60, and 90 d of gestation and at parturition for serum E and Se assays. Lymphocytes and polymorphonuclear cells (PMN) were isolated from the blood, colostrum, and 4-d milk samples for immune studies. Compared with the control (+E+Se) diet, the -E-Se diet reduced (P < .05) the serum tocopherol and Se concentrations, the mitogenic responses of lymphocytes of peripheral blood (PBL) and colostrum (CL), the phagocytic activity of blood and colostral PMN, and the microbicidal activity of blood, colostral, and milk PMN. The -E+Se diet reduced (P < .05) the serum tocopherol concentrations, the mitogenic responses of PBL and CL, and the phagocytic activity of PBL. The +E-Se diet reduced (P < .05) serum Se concentrations and the phagocytic activity of PMN. The data indicated that E restriction depressed PBL and PMN immune functions, whereas Se restriction depressed mainly PMN function.

Animals↗

PubMed1999

Enhanced total peripheral vascular responsiveness in hypertension accords with the amplifier hypothesis.

BACKGROUND: Increases in vascular resistance (or the reciprocal, vascular conductance) in response to constrictor drugs are amplified (or attenuated) in the hindquarter vascular bed of hypertensive rats and rabbits. However, such changes have not been observed for the total peripheral circulation. OBJECTIVE: To assess whether the vascular amplifier applies to the total peripheral circulation in conscious hypertensive rabbits. METHODS: Rabbits were implanted with a flow probe for measuring cardiac output, a left atrial catheter for infusing dilator (adenosine) and constrictor (methoxamine) drugs, and ear artery and vein catheters for measuring mean arterial pressure (MAP) and for giving ganglion blockade. Data from full dose-total peripheral resistance (TPR) or total peripheral conductance (TPC) response curves to adenosine and methoxamine were combined into a logistic function extending from near full dilatation to near maximum constriction. RESULTS: Changes in MAP induced by methoxamine and adenosine were markedly greater in the 'wrap' rabbits (those with renal cellophane wrapping) compared with the sham animals. In the 'wrap' rabbits, the slopes and ranges of the adenosine-TPR response curve and the methoxamine-TPC response curve were 200% and 60%, respectively, of sham values. These data show that TPR changes are amplified, and TPC changes attenuated, to dilator and constrictor stimuli. The relationship between dose-average vascular radius (r; based on Poiseuille's law) over the full range of vascular tone showed that r was narrower in hypertension, but, in contrast to TPR, the degree of narrowing was almost the same between maximum dilatation and constriction. CONCLUSION: The total peripheral circulation in experimental hypertension is a TPR amplifier, or TPC attenuator, in the rabbit, consistent with well-established data in the major vascular beds.

Adenosine↗

PubMed1983

Rapid pituitary and peripheral tissue responses to intravenous L-triiodothyronine in hypothyroidism.

Acute cardiovascular, renal, pulmonary, metabolic, and pituitary responses to therapy of hypothyroidism with 25 micrograms iv T3 (group I G-I, n = 11) or 50 micrograms iv T3 (group II, G-II, n = 10)/day for 1 week have been studied. Serum T3 levels were acutely normalized in both groups with the mean basal serum T3 levels (X +/- SE) after 7 days, 98 +/- 10 micrograms/dl and 229 +/- 19 ng/dl, respectively. Myocardial performance, noninvasively assessed by the pulse wave arrival time (QKd) and the phonocardiographic systolic time interval ratio was significantly altered after 1 day of therapy (QKd for G-I = -10 +/- 4 msec, P less than 0.05; and for G-II = -18 +/- 14 msec, P less than 0.01). After 7 treatment days, both the mean QKd (203 +/- 7 msec, P less than 0.001) and phonocardiographic systolic time interval ratio (0.41 +/- 0.02, P less than 0.01) were within the normal range in G-II. Abnormal pretreatment renal excretion of an oral water load (G-I, 65 +/- 6%; and G-II, 57 +/- 6%) was also reversed after 1 week (G-I, 84 +/- 5%, P less than 0.05; and G-II, 89 +/- 5%, P less than 0.01). Patients with blunted hypercapnic (n = 6) and hypoxic (n = 4) ventilatory drives were improved in both groups after 6 days. The mean basal metabolic rate, serum cholesterol, and serum creatine phosphokinase were altered by the week of therapy in a dose-response manner, and were in the normal range in G-II. Pituitary TSH secretion was promptly suppressed in both groups. Two hours after the first T3 dose, the mean serum TSH for G-I and G-II decreased to 85% (P less than 0.02) and 70% (P less than 0.001) of their respective pretreatment values. After 7 days of therapy, the mean basal TSH levels had declined to 75% (P less than 0.001) and 5% (P less than 0.001%) of pretreatment, respectively. In comparison with previous observations of responses to 100 micrograms/day iv T4 for 1 week, the 25 micrograms dose T3 was equivalent in terms of changes in basal serum T3 and peripheral (nonpituitary) tissue responses, but less effective than T4 in lowering serum TSH. Based on these parameters, 50 micrograms/day iv T3 was the most effective of the three regimens within this time frame. The implications of these observations in the clinical management of severe complicated myxedema are discussed.

Adult↗

PubMed1992

Responses of peripheral blood cells to acute insulin-induced hypoglycaemia in humans: effect of alpha-adrenergic blockade.

Acute hypoglycaemia provokes rapid changes in peripheral blood cell counts. To examine possible adrenergic mechanisms modulating these changes, counts of peripheral blood cells including lymphocytes, granulocytes and red cells were measured in response to acute hypoglycaemia in a group of six normal subjects in control conditions (study 1), and during alpha-adrenergic blockade with phentolamine (study 2). In study 1 hypoglycaemia provoked a biphasic white cell response, with an early rise in lymphocyte count and a later rise in granulocyte count. The red cell count increased modestly following hypoglycaemia. During alpha-adrenergic blockade, the rise in total white cell count was diminished, with the rise in the lymphocyte count being greatly obtunded. The rise in the granulocyte count was unchanged. The increment of the red cell count during acute hypoglycaemia was abolished. These findings suggest that the increments of peripheral lymphocyte and red cell counts in response to acute insulin-induced hypoglycaemia are mediated via alpha-adrenoreceptors.

Acute Disease↗

PubMed1997

Opioid modulation of attention-related responses: peripheral-to-central progression and development of mu influence as learning occurs.

Endogenous opioids modulate attention-related bradycardiac responses evoked by novel stimuli and Pavlovian conditioned signals, and these effects are distinct from those of endogenous opioids on memory. We investigated the role of peripheral opioid receptors in modulating attention and Pavlovian learning, in rabbits tested for bradycardiac orienting responses to novel tones, and for Pavlovian conditioning and extinction of cardiac discrimination. Pretraining, IV treatment with the opiate antagonist naloxone-HCl (0.1-0.5 mg/kg) facilitated initial development of Pavlovian conditioned discrimination and delayed its later extinction, compared to saline vehicle, as previously observed. Pretraining treatment with its peripherally acting analog, quaternary naloxone-methiodide (1.29-6.47 mg/kg), also promoted initial development, but not extinction, of discrimination, and it reduced the magnitude of bradycardiac orienting responses and of tachycardiac unconditioned responses. Treatment with the selective mu-antagonist peptide CTOP (10-30 microg/kg) facilitated conditioned responses and reduced unconditioned responses, somewhat later during training, but it did not reliably affect extinction or orienting responses. These results confirm an important role of peripheral opioids in regulating attentional and associative functions involved in orienting and the earliest stage of Pavlovian learning, prior to development of central opioid regulation of later associative, hedonic and mnemonic functions. These findings also suggest that cardiovascular opioid receptors might mediate peripheral opioid influences on attention and early association formation, via modulation of cardiac responses to stimuli and autonomic sensory feedback to the brain.

Animals↗

PubMed1983

Effect of factors other than pathologic status on responsiveness of peripheral blood mononuclear cells from patients with chronic periodontitis.

Studies were designed to assess factors other than pathologic status of the cell donor which affect the blastogenic responsiveness in vitro of peripheral blood mononuclear cells (PBMs) from normal donors and patients with periodontitis. Cultures were established and activated using phytohemagglutinin-P (PHA) or homogenates of Actinomyces viscosus (AVIS), a gram-positive plaque microorganism, and Fusobacterium nucleatum (FUSO), a gram-negative plaque microorganism. Activation was assessed by measuring the incorporation of labeled precursor into DNA. The effects of incubation time, vessel shape, cell concentration, prostaglandin E2 and indomethacin on blastogenic responsiveness were studied. Blastogenic responsiveness became maximal after 5 to 8 days' activation with the bacterial substances, and after 3 days' activation with PHA. Radioactivity incorporated by cultures in microtest wells with flat, round and conical bottoms was 5.9, 7.8 and 10.6 X 10(3) cpm, respectively. Cultures of cells from all of the patients and normal subjects were activated by PHA, AVIS and FUSO, and cell concentration was a major determinant of the magnitude of the blastogenic response. Responsiveness of cultures from all patients and control subjects activated with AVIS and FUSO was inhibited significantly by prostaglandin E-2 (PGE2) at a concentration of 10 microM. Inhibition was generally 50% or greater. Indomethacin, an inhibitor of prostaglandin production, at a concentration of 0.5 micrograms/ml significantly enhanced responsiveness of AVIS- and FUSO-activated cultures from control donors and patients, indicating that prostaglandins are produced endogenously, and that they affect cell responsiveness. The effect of PGE2 and indomethacin on PHA-activated cultures was more variable and, where present, of a lesser magnitude than that observed for cultures activated with bacterial homogenates. In most cultures the effects were not statistically significant. Our data show that in studies of lymphocyte activation, the incubation time, culture-vessel shape, cell concentration and presence of endogenous inhibitors need to be taken into account.

Adult↗

PubMed1999

Aerobic exercise training can reverse age-related peripheral circulatory changes in healthy older men.

BACKGROUND: The age-related decline in maximal oxygen consumption is attenuated by habitual aerobic exercise. However, the relative effects of training on central and peripheral responses to exercise in older subjects are not known. The present study assessed the contribution of central and peripheral responses to the age-associated decline in peak oxygen consumption and compared the effect of exercise training in healthy older and younger subjects. METHODS AND RESULTS: Ten older and 13 younger men underwent invasive measurement of central and peripheral cardiovascular responses during an upright, staged cycle exercise test before and after a 3-month period of exercise training with cycle ergometry. At baseline, cardiac output and AV oxygen difference during exercise were significantly lower in older subjects. With training, the older and younger groups increased maximal oxygen consumption by 17.8% and 20.2%, respectively. Peak cardiac output was unchanged in both groups. Systemic AV oxygen difference increased 14.4% in the older group and 14.3% in the younger group and accounted for changes in peak oxygen consumption. Peak leg blood flow increased by 50% in older subjects, whereas the younger group showed no significant change. There was no change in peak leg oxygen extraction in the older group, but in the younger group, leg AV oxygen difference increased by 15.4%. CONCLUSIONS: These findings suggest that the age-related decline in maximal oxygen consumption results from a reversible deconditioning effect on the distribution of cardiac output to exercising muscle and an age-related reduction in cardiac output reserve.

Adult↗

PubMed1995

The adaptive response of peripheral blood lymphocytes to low doses of mutagenic agents in patients with ataxia telangiectasia.

The inducible ability of adaptive response by low doses of gamma rays or bleomycin was studied in peripheral blood lymphocytes of healthy donors and in ataxia telangiectasia patients. An adaptive response was found in the lymphocytes of healthy donors pretreated with either gamma rays or bleomycin, however in individuals heterozygous for ataxia only bleomycin was effective. In the two ataxia telangiectasia homozygotes tested no adaptive response was found either after low-dose gamma rays or after bleomycin. The preliminary results indicate that the adaptive response might be influenced by various factors.

Adaptation, Physiological↗

PubMed1997

Peripheral vasoconstrictor responses to sympathetic activation in diabetic patients: relationship with rheological disorders.

The sympathetic nervous system regulates peripheral blood flow. This study investigated sympathetic vascular control in diabetic patients by measuring cutaneous blood flow (CBF) with a laser Doppler device at rest and during three sympathetic activation tests: deep-breathing, changing positions from sitting to standing, and using the Valsalva maneuver. The influence of various factors, particularly rheological changes, was also assessed. Forty-two type II diabetes mellitus (non-insulin-dependent [NIDDM]) patients and 14 control subjects were studied. The mean value and standard deviation (SD) of basal CBF at rest were not significantly different in the two groups. In 12 NIDDM patients, the SD was less than the lowest limit found in the controls. During the three tests, the reduction in CBF and its downward slope were lower in NIDDM patients than in controls, with the greatest difference occurring during the deep-breathing test. During this test, the downward slope of CBF was less than the lowest control level in 14 NIDDM patients. The log SD of basal CBF correlated with the decrease in CBF during the sitting-to-standing and Valsalva tests in control subjects and during all three tests in NIDDM patients. In NIDDM patients, log mean basal CBF correlated negatively with the log erythrocyte filtration index ([FI] an index of rigidity) and positively with hemoglobin A1c (HbA1c). The log downward slope of CBF during the deep-breathing test correlated negatively with log erythrocyte Fl. The log downward slope of CBF during the sitting-to-standing and Valsalva tests correlated positively with total cholesterol and triglycerides, respectively. Basal CBF and the CBF response to these tests did not correlate with retinopathy, nephropathy, peripheral neuropathy, or heart rate variations during these tests. This study suggests that CBF assessment by laser Doppler flowmetry affords an attractive noninvasive way to investigate sympathetic nervous function in diabetic patients. The amplitude of changes in basal CBF and the decrease in CBF during the deep-breathing test show that this is a simple and sensitive procedure for detecting sympathetic nerve dysfunction. Moreover, theological blood properties and metabolic factors seem to strongly influence resting CBF and vasomotor reflexes.

Adult↗

PubMed2001

Effect of interleukin-1 receptor antagonist on concanavalin A response of peripheral blood mononuclear cells from newborn calves.

The coexistence of interleukin (IL)-1beta with IL-1 receptor antagonist (ra) in bovine colostrum and the possibility of simultaneous transfer of these cytokines to neonates via colostrum have been demonstrated. In the present study, we investigated the effect of IL-1ra on the mitogenic response of calf peripheral blood mononuclear cells (PBMC) stimulated by concanavalin A (ConA), which was mediated by IL-1. Pretreatment of PBMC with recombinant bovine (rb) IL-1ra alone significantly suppressed the proliferation of ConA-stimulated cells. However, in the presence of rbIL-1beta, the suppressive activity of rbIL-1ra was counteracted. These results suggest that coexistence of IL-1ra with IL-1 in colostrum may have no effect on the activation of the neonatal immune system by IL-1beta.

Animals↗

PubMed1992

Bovine virus diarrhoea virus induces in vitro a proliferative response of peripheral blood mononuclear cells from cattle immunized by infection.

The ability of bovine peripheral blood mononuclear cells (PBMC) to mount a proliferative response to bovine virus diarrhoea virus (BVDV) in vitro was examined. After culturing PBMC in the presence of a non-cytopathic strain of BVDV for 6 days, the magnitude of PBMC proliferation was measured as incorporation of radiolabelled thymidine, present during the last 18 h. Live, but not heat-inactivated, BVDV evoked a proliferative response of PBMC obtained from cattle seropositive to the virus. However, PBMC from seronegative or persistently BVDV-infected animals were not stimulated by BVDV. The presence of live BVDV did not alter the proliferative response of PBMC to stimulation with concanavalin A.

Animals↗

PubMed1999

Effect of vitamin C and E in modulating peripheral vascular response to local cold stimulus in man at high altitude.

At high altitude (HA), cold stress is aggravated by hypoxia, perhaps due to the increased formation of free radicals which trigger oxidative stress. This may be one of the contributing factors for adverse effects including disturbances in microcirculation and capillary permeability resulting in decreased peripheral blood flow. This leads to altered cold-induced-vasodilatation (CIVD) response on exposure to HA. The present study was conducted on 40 male volunteers (4 groups of 10 each) to evaluate the utility of supplementation of vitamin C (500 mg/d)and vitamin E (400 mg/d) singly, as well as in combination, in modulating peripheral vascular response by assessing CIVD response under local cold stimulus both at Delhi (200 m) and at HA (3,700 m). On exposure to 3,700 m, decreased CIVD response was observed in all the groups. The responses were better in vitamin supplemented groups, in general, as compared to the placebo group. The best CIVD response was seen in the vitamin C (singly)-treated group. Administration of vitamin C and E together did not result in any additional benefit. Facilitation of CIVD response due to supplementation of vitamin C may be attributed to its (a) antioxidant effect, and (b) major physiological functions of increased metabolism and thermogenic properties, facilitation of collagen synthesis, restoration of intercellular substances and better maintenance of the rheological status of the blood. Hence, vitamin C is effective for improving peripheral blood flow and thereby reduces the incidence of cold injuries during acclimatization or outdoor duties at HA.

Adaptation, Physiological↗

PubMed1984

Inferior colliculus single unit responses to peripheral electrical stimulation in normal and congenitally deaf mice.

We have investigated the single unit response in the inferior colliculus of the mouse to electrical pulse stimulation at the auditory periphery. The experimental animals were deafness mutant mice (dn/dn), which have hereditary congenital peripheral pathology. The control animals were normal littermates (+/dn). Monopolar electrical pulses were applied either to the modiolus or the round window and the evoked single unit activity was recorded in the contralateral inferior colliculus (IC). Two types of single unit response were observed: a single-spike response, and a multiple-spike response. There was a predominance of the former in the control animals and of the latter in the mutants. For both modes of stimulation the group mean threshold of response was lower in mutants compared to controls, whilst the maximum number of evoked spikes per 50 presentations was higher in mutants than control animals. The mutant response pattern was similar to that seen in animals with experimentally induced auditory deprivation. The suitability of the deafness mutant as a model for the investigation of coding strategies for cochlear implants is discussed.

Animals↗

PubMed1984

Drinking and renal responses to peripherally administered osmotic stimuli in the pigeon (Columbia livia).

Pigeons drank copiously in response to intravenous (I.V.) infusion of approximately equi-osmolar hypertonic solutions of NaCl (0.5 M), sucrose (1.0 M) or mannitol (1.0 M). I.V. infusions of hypertonic glucose (1.0 M) or urea (1.0 M) were less effective in causing drinking. The calculated percentage change in plasma osmolality at the onset of drinking was similar for the three hypertonic solutions, NaCl, sucrose and mannitol, irrespective of the concentration of the solution infused. A greater volume of water was drunk in response to I.V. infusion of 7 ml of 1.0 M-sucrose than in response to a similar volume of 1.0 M-NaCl or mannitol. This appeared to be in response to the large diuresis caused by sucrose infusions. Excretion of the osmotic load was more rapid following I.V. hypertonic sucrose and mannitol than following hypertonic NaCl, glucose or urea in the 10 h of the experiment. In anaesthetized pigeons, I.V. infusion of hypertonic NaCl (0.5 M), sucrose (1.0 M) or urea (1.0 M) caused similar increases in plasma osmolality. The haematocrit was significantly reduced after NaCl or sucrose but not after urea. Plasma Na+ concentration was significantly increased after NaCl, and decreased after sucrose, whereas urea produced little change. Following I.V. hypertonic NaCl or urea, the Na+ concentration of the cerebrospinal fluid (c.s.f.) was increased and its flow reduced compared with isotonic NaCl infusions. Hypertonic sucrose stopped the flow of c.s.f. almost completely during the course of the experiment. These experiments suggest that the drinking and renal responses of pigeons following osmotic stimuli are similar to those of mammals and that they appear to retain Na+.

Animals↗

PubMed2004

Interleukin (IL)-6, but not IL-1, induction in the brain downstream of cyclooxygenase-2 is essential for the induction of febrile response against peripheral IL-1alpha.

IL-1 is an endogenous pyrogen produced upon inflammation or infection. Previously, we showed that, upon injection with turpentine, IL-1 is induced in the brain in association with the development of fever. The role of endogenous IL-1 in the brain and the signaling cascade to activate thermosensitive neurons, however, remain to be elucidated. In this report, febrile response was analyzed after peripheral injection of IL-1alpha. We found that a normal febrile response was induced even in IL-1alpha/beta-deficient mice, indicating that production of IL-1 in the brain is not necessarily required for the response. In contrast, IL-6-deficient mice did not exhibit a febrile response. Cyclooxygenase (Cox)-2 expression in the brain was strongly induced 1.5 h after injection of IL-1alpha, whereas IL-6 expression was observed 3 h after the injection. Cox-2 expression in the brain was not influenced by IL-6 deficiency, whereas indomethacin, an inhibitor of cyclooxygenases, completely inhibited induction of IL-6. These observations suggest a mechanism of IL-1-induced febrile response in which IL-1 in the blood activates Cox-2, with the resulting prostaglandin E(2) inducing IL-6 in the brain, leading to the development of fever.

Animals↗

PubMed1979

Concurrent responses of peripheral blood and splenic mononuclear cells to antigenic and mitogenic stimulation in human hepatosplenic schistosomiasis.

Lymphocyte reactivity and its control was assessed in human hepatosplenic schistosomiasis, a disease in which host hypersensitivity may contribute to long-term morbidity. Antigen- and mitogen-induced incorporation of [3H]thymidine was evaluated in peripheral blood and splenic mononuclear cells of 15 patients at the time of splenectomy. The response to phytohemagglutinin (PHA) was depressed in the peripheral blood of 42% and in the spleen cells of 70% of these patients. Significant stimulation was noted, however, upon culture of blood with soluble schistosome egg antigen (SEA) in 80% and of spleen cells in 100% of the patients whose respective responses to PHA were depressed. The contribution of adherent cells to the overall response of mononuclear cells was evaluated by depletion techniques. A significant and specific decrease in the response of the resulting thymus-derived (T) lymphocyte-enriched splenic mononuclear cells to SEA was noted. These studies suggest preferential preservation of the response of circulating and splenic lymphocytes to SEA despite impairment of PHA reactivity in human hepatosplenic schistosomiasis, which may be causally related to the advanced disease of this group of patients. Moreover, activity of helper adherent cells was consistently restricted to the splenic T-lymphocyte response induced by the specific antigen SEA.

Adolescent↗