Bilateral occlusion of the internal carotid arteries. Presenting symptoms in 74 patients and a prospective study of 34 medically treated patients

The presenting characteristics of 74 patients with atherosclerotic occlusion of both internal carotid arteries are described. All had suffered either ischaemic hemisphere infarcts (80%) and/or transient ischaemic attacks (80%) involving one (78%) or both (22%) carotid territories. In addition, 10 subjects (14%) incurred recurrent vertebrobasilar or presyncopal episodes, many of which appeared secondary to haemodynamic insufficiency. The incidence of risk factors and concomitant vascular disease was high; 93% gave a history of heavy smoking. Thirty-four subjects were treated conservatively and followed prospectively for a mean of 42 months. Eighteen patients (53%) suffered further cerebrovascular events, an ischaemic event rate of 15% per patient per year. These were isolated transient ischaemic attacks (TIAs) in 7 and stroke in 11 patients. The latter suffered a total of 15 strokes during the follow-up period of 42 months; the annual stroke rate was 13% per patient year. Patients who had presented with ischaemic events involving more than one carotid territory were significantly more prone to subsequent cerebral infarction than those in whom symptoms had been confined to one territory (P less than 0.05). None of the 5 patients with haemodynamic TIAs who were managed conservatively developed a stroke during the follow-up period and their symptoms remitted spontaneously. Deaths per year amounted to 8%. Twenty-four patients (71%) survived, of whom half were either symptom-free or minimally disabled. In this group of preselected patients, which excludes those with severe deficits at presentation, bilateral occlusion of the carotid arteries may be a condition compatible with useful existence.

Actions of a progestogen on human breast cancer cells: mechanisms of growth stimulation and inhibition

Medroxyprogesterone acetate (MPA) reduced the proliferation of MCF-7 cells with a maximal response at 100 nM. A subline ('M' cells) resistant to this action remained responsive to antioestrogen but showed a poor response to dexamethasone (DEX). Experiments with mixtures of MPA and DEX showed that MPA acts on wild-type MCF-7 cells through a glucocorticoid as well as a progestogen mechanism. The growth of 'M' cells was stimulated by MPA at 100 nM or greater and the drug increased polyamine concentrations in 'wild-type' as well as 'M' cells. It is suggested that both progestogen and glucocorticoid receptors may mediate the effects of high-dose MPA therapy in breast cancer. The possible stimulation of the growth of some cell types by MPA requires further investigation.

Protracted severe immune dysregulation induced by cardiopulmonary bypass: a predisposing etiologic factor in blood transfusion-related AIDS?

A large percentage of patients with blood transfusion related AIDS received their transfusion during cardiac surgery requiring cardiopulmonary bypass. We hypothesized that the procedure of cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery might be associated with severe immune dysregulation and hence predispose this group in particular to the acquisition of blood transfusion transmitted AIDS. T-cell subset enumeration and their ratio (T4/T8) and T-cell function (local GVH reaction) were serially studied before, during, and 1 and 6 days after surgery in 15 patients undergoing cardiac surgery requiring CPB, in 10 patients undergoing cancer resections (CA), and 11 patients without cancer undergoing elective, non-cardiac general surgical procedures (GEN). Compared to the preoperative values, a significant decline (p less than 0.002) in T4/T8 ratios occurred during CPB (1.63 +/- 0.80 vs 2.55 +/- 0.95), during CA (1.26 +/- 0.71 vs 1.81 +/- 0.72), and during GEN procedures (1.18 +/- 0.59 vs 1.64 +/- 0.68). T4, T8, and T4/T8 ratios returned to preoperative values in both the CA and GEN groups by the first postoperative day; in contrast, T4/T8 ratios remained significantly depressed (p less than 0.05) in CPB patients on the first and also on the sixth postoperative days when compared to preoperative values. This sustained depression in T4/T8 ratios is attributable to a significant increase in the proportion of T8 (suppressor cell) subset in the CPB patients which persisted through the sixth postoperative day. In contrast, in CA and GEN, the proportion of T8 subset returned to the preoperative level by the sixth postoperative day.(ABSTRACT TRUNCATED AT 250 WORDS)

The inhibition of commitment of mouse erythroleukemia cells by steroids involves a glucocorticoid-receptor mediated process(es) acting at the nuclear level

Dexamethasone has been shown to inhibit dimethylsulfoxide (DMSO)-induced differentiation of mouse erythroleukemia (or Friend) cells by blocking commitment to terminal erythroid maturation. In this study, we confirmed previous reports indicating the presence of glucocorticoid receptors in murine erythroleukemia cells and examined the mechanism(s) by which steroids block commitment. Untreated murine erythroleukemia cells contain dexamethasone receptors which decrease in number during DMSO-induced cell differentiation. When steroids of different classes (estrogenic, androgenic, glucocorticoid) were tested for inhibition of commitment and for displacement of [3H]dexamethasone from its receptors in DMSO-treated cells, we observed that the glucocorticoids dexamethasone, prednisolone and hydrocortisone, all blocked commitment and substantially displaced [3H]dexamethasone. In contrast, steroids other than glucocorticoids failed to inhibit commitment or displace [3H]dexamethasone. Analysis of kinetics of dexamethasone binding to chromatin revealed that dexamethasone binds to the nucleus via the receptor and preferentially interacts with active chromatin. Inhibition of commitment by dexamethasone persisted in cells released from this agent and reincubated with DMSO in the presence of another glucocorticoid of similar affinity to steroid receptors; inhibition of commitment, however, was not obtained when cells removed from dexamethasone were incubated in the presence of beta-estradiol, progesterone and testosterone. These data indicate that inhibition of commitment of mouse erythroleukemia cells by steroids is associated with binding to glucocorticoid receptors and may involve interactions of steroids and their receptors with regions of chromatin.

Bilateral occlusion of the trunk of the middle cerebral artery. Results of an international randomized trial. The EC/IC Bypass Study Group

Bilateral occlusion of the middle cerebral artery (MCA) trunk theoretically should be a very severe condition, but its actual prognosis has never been studied. Nine of 1,377 patients (7 Asians, 1 Black, 1 Caucasian) from the Cooperative Study of Extracranial/Intracranial Arterial Anastomosis were found to have atherosclerotic bilateral occlusion of the middle cerebral artery (MCA) trunk before entering the trial. Three presented with a stroke followed by a contralateral stroke, two experienced a unilateral stroke, two had a unilateral stroke preceded by ipsilateral TIAs, one had a unilateral stroke preceded by TIAs on both sides and one experienced isolated unilateral TIAs. Retrograde filling to the distal MCA was universally present. During follow-up (mean: 45 months), only one (non-operated) patient had further cerebrovascular events, and ultimately a fatal stroke. One additional patient died of sepsis and one had a silent myocardial infarct. All survivors resumed their previous activities. This study shows that in bilateral MCA trunk occlusion, the long-term prognosis is reasonable in the patients who do not present with a devastating stroke.

Sciatic nerve palsy complicating umbilical arterial catheterization

A term newborn infant developed a right sciatic nerve palsy after ischaemic necrosis of the gluteal region following umbilical arterial catheterization. The nerve lesion was believed to be caused by entrapment and compression by scar tissue. Recovery was slow and remained incomplete up to 6 months of age.

Prevention of anthracycline-induced cytotoxicity in hemopoietic cells by hemin

Anthracyclines such as Adriamycin (ADR) and daunomycin markedly inhibit cell growth in vivo and in vitro. These studies demonstrate that 30 microM hemin, which induces hemoglobin synthesis in human and murine erythroleukemia cells in culture, markedly decreases the cytotoxicity of ADR in a variety of hemopoietic cell lines (K562, HEL-1, MEL-745, HL-60, and U937) and in erythroid burst-forming cells from normal human marrow. Hemin failed to protect four of the five nonhemopoietic cell lines tested, including MCF-, breast adenocarcinoma cells, C-205 colon carcinoma cells, mouse 3T3 fibroblasts, and mouse kidney VERO cells. Hemin did protect human neuroblastoma IMP-32 cells from ADR cytotoxicity; however, this nonhemopoietic cell line undergoes dendrite formation in response to hemin induction. Cytofluorographic analysis of cellular ADR content and labeling studies with [3H]daunomycin demonstrated that hemin decreases the intracellular accumulation of these anthracyclines by more than 50% in K562 erythroleukemia cells. These studies indicate that small doses of hemin prevent intracellular accumulation of anthracyclines and thereby markedly reduce anthracycline toxicity to cells. Since this protective effect is observed preferentially with hemopoietic cells, it is possible that this finding could be exploited to protect the bone marrow from the cytotoxic action of anthracyclines during therapy for nonhemopoietic tumors.

Hormonal therapies for breast cancer: can progestogens stimulate growth?

The human breast cancer cell line, MCF-7, displays many of the properties of breast tumours in vivo and, in particular, shows similar responses to hormones. Medroxyprogesterone acetate significantly inhibited cell proliferation, but, following continued treatment, this effect was lost and further exposure to the drug stimulated cell proliferation and increased polyamine content while tamoxifen inhibited growth. Prolonged administration of progestogens may thus have adverse effects and should be assessed critically.

Relationship of mitochondrial membrane potential to hemoglobin synthesis during Friend cell maturation

Previous studies have shown that exposure to imidazole dissociates hemoglobin synthesis from other aspects of cell maturation in dimethylsulfoxide (DMSO)-treated mouse erythroleukemia (MEL) cells. In the present study, we have found that imidazole causes hyperpolarization of the mitochondrial membrane in MEL cells exposed to DMSO, in contrast to the depolarization observed with DMSO alone. Like the defect in hemoglobin synthesis, membrane hyperpolarization is reversible upon removal of imidazole and incubation of cells with DMSO alone. These correlations suggest that alterations in the electrostatic properties of the mitochondrial membrane, due directly or indirectly to the effects of imidazole, interfere with heme synthesis but not with other aspects of the maturation process in these developing erythroid cells.

Analysis of commitment of human leukemia HL-60 cells to terminal granulocytic maturation

Analysis of commitment of human promyelocytic leukemia HL-60 cells to terminal granulocytic maturation induced by dimethyl sulfoxide (DMSO) or retinoic acid (RA) was accomplished using biochemical measurements and a plasma clot clonal assay system that permits a high plating efficiency of 40 to 60%. Commitment to granulocytic maturation occurs very rapidly. When cells are exposed to these inducers for only 8 to 18 h, an interval much shorter than a single generation time, and are then subcultured in inducer-free plasma clots, they demonstrate a decrease in proliferative capacity and form colonies composed of mature nitroblue tetrazolium (NBT)-positive cells along with occasional colonies containing both NBT-positive and NBT-negative cells; in both types of colony, the NBT-positive cells are widely dispersed. Undifferentiated HL-60 cells give rise to compact NBT-negative colonies of large size without cell migration. HL-60 cell differentiation induced by either DMSO or RA is associated with a progressive decline in both DNA and RNA synthesis; this includes transcriptional inactivation of ribosomal DNA sequences. In contrast to DMSO, which induces development primarily of metamyelocytes, RA treatment leads to the accumulation of more mature band and segmented neutrophils; sequential exposure of cells pretreated with DMSO to RA alone fails to cause rapid appearance of segmented neutrophils. From these studies, we conclude that HL-60 cells become very rapidly committed to terminal maturation and that DMSO and RA appear to induce granulocytic maturation via two different mechanisms.

Normal function of CR1 on affected erythrocytes of patients with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia in which affected erythrocytes (E) are abnormally sensitive to lysis by autologous complement. Affected E from patients with PNH (PNH-E) are deficient in an E membrane regulatory protein of complement, decay-accelerating factor (DAF). Because a functional defect in a second membrane regulatory protein of complement, CR1 (C3b receptor), has also been hypothesized, severely affected PNH-E (type III PNH-E) were tested for abnormalities in CR1 by four methods. E from two patients with 100% type III PNH-E had 3201 and 6783 sites per cell for binding of 125I-labeled rabbit polyclonal F(ab')2 anti-CR1. These values fall within the normal range of CR1 antigenic sites per cell (1267 to 7915, mean = 5,014 +/- 155 SEM) established by assaying the E from 113 healthy donors. The Ka of CR1 on type III PNH-E for 125I-labeled C3b dimer was 2.06 X 10(7) M-1, and the Ka values for the binding of the same ligand to the E from two healthy individuals were 2.45 X 10(7) M-1 and 1.58 X 10(7) M-1. In an assay designed to measure the capacity of human E (Eh) to accelerate the decay of the classical C3 convertase deposited on 1 X 10(7) bystander sheep E (EAC1gp,4bh,2agp), the half-life (t 1/2) of this convertase was diminished from 18.1 min (range 15.2 to 22.9) to 8.1 min (range 7.4 to 8.5) by the addition of 1 X 10(7) normal Eh, to 6.2 min by 100% type III PNH-E, and to 7.5 min by Eh pretreated with an IgG fraction of human antiserum directed against the D antigen of the Rh system. In contrast, Eh (t 1/2 = 7.4) pretreated with a saturating dose of F(ab')2 anti-CR1, and CR1-deficient Eh (less than 10 CR1 molecules/E) from a patient with systemic lupus erythematosus, showed a loss of convertase decay-accelerating capacity to t 1/2 = 11.6 and t 1/2 = 12.4, respectively. Type III PNH-E pretreated with anti-CR1 demonstrated a total loss of their decay-accelerating capacity (t 1/2 = 19.9). In an assay of I cofactor activity, soluble C3b was rapidly converted to iC3b by purified I plus Eh or type III PNH-E, whereas CR1-deficient Eh exhibited less than 5% the I cofactor activity of normal Eh.(ABSTRACT TRUNCATED AT 400 WORDS)

Normal function of CR1 on affected erythrocytes of patients with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia in which affected erythrocytes (E) are abnormally sensitive to lysis by autologous complement. Affected E from patients with PNH (PNH-E) are deficient in an E membrane regulatory protein of complement, decay-accelerating factor (DAF). Because a functional defect in a second membrane regulatory protein of complement, CR1 (C3b receptor), has also been hypothesized, severely affected PNH-E (type III PNH-E) were tested for abnormalities in CR1 by four methods. E from two patients with 100% type III PNH-E had 3201 and 6783 sites per cell for binding of 125I-labeled rabbit polyclonal F(ab')2 anti-CR1. These values fall within the normal range of CR1 antigenic sites per cell (1267 to 7915, mean = 5,014 +/- 155 SEM) established by assaying the E from 113 healthy donors. The Ka of CR1 on type III PNH-E for 125I-labeled C3b dimer was 2.06 X 10(7) M-1, and the Ka values for the binding of the same ligand to the E from two healthy individuals were 2.45 X 10(7) M-1 and 1.58 X 10(7) M-1. In an assay designed to measure the capacity of human E (Eh) to accelerate the decay of the classical C3 convertase deposited on 1 X 10(7) bystander sheep E (EAC1gp,4bh,2agp), the half-life (t 1/2) of this convertase was diminished from 18.1 min (range 15.2 to 22.9) to 8.1 min (range 7.4 to 8.5) by the addition of 1 X 10(7) normal Eh, to 6.2 min by 100% type III PNH-E, and to 7.5 min by Eh pretreated with an IgG fraction of human antiserum directed against the D antigen of the Rh system. In contrast, Eh (t 1/2 = 7.4) pretreated with a saturating dose of F(ab')2 anti-CR1, and CR1-deficient Eh (less than 10 CR1 molecules/E) from a patient with systemic lupus erythematosus, showed a loss of convertase decay-accelerating capacity to t 1/2 = 11.6 and t 1/2 = 12.4, respectively. Type III PNH-E pretreated with anti-CR1 demonstrated a total loss of their decay-accelerating capacity (t 1/2 = 19.9). In an assay of I cofactor activity, soluble C3b was rapidly converted to iC3b by purified I plus Eh or type III PNH-E, whereas CR1-deficient Eh exhibited less than 5% the I cofactor activity of normal Eh.(ABSTRACT TRUNCATED AT 400 WORDS)

Molecular and cellular mechanisms of leukemic hemopoietic cell differentiation: an analysis of the Friend system

Murine erythroleukemia (MEL or Friend) cells grown in culture and induced to differentiate into cells resembling orthochromatic normoblasts provide a suitable system for uncovering molecular and cellular mechanisms of hemopoiesis and for understanding globin gene regulation. Inducer-treated cells undergo an irreversible commitment to maturation and accumulate large amounts of hemoglobin. Clonal analysis of commitment of individual cells combined with biochemical measurements has revealed that MEL cell differentiation is a highly coordinated set of events (program) leading to the differentiated erythroid state. The developmental program of MEL cells consists of early and late processes. The early events appear to be membrane-mediated processes which operate independently of each other and lead to commitment to terminal maturation and hemoglobin synthesis. Inducer-treated cells express an ability to remember ("memory response") previous exposure to inducer and to continue their differentiation after discontinuous exposure to inducer; expression of "memory response" occurs early in differentiation and affects both the initiation of commitment and accumulation of globin mRNA in a similar manner in inducer-treated cells. Commitment to maturation appears to be the central process responsible for determining the pattern of gene expression, limitation of proliferative activity and nuclear condensation. Commitment, however, can occur independently of hemoglobin synthesis. Although initiation of commitment is associated with early membrane-mediated events (e.g., ion-transport), maintenance and completion of maturation erythroid state is a result of a number of cellular processes. These processes are discussed in relation to the molecular and cellular mechanisms of initiation and completion of MEL cell differentiation. The role of the MEL system as a model for studying mouse and human globin gene regulation is presented.

Monoclonal antibodies to immunodeterminants of lipoteichoic acids

Murine hybrid cell lines producing monoclonal antibodies directed against determinants present on lipoteichoic acids were generated. Hapten inhibition studies showed that one group of monoclonal antibodies was inhibited by deacylated cardiolipin, and the second group was inhibited by kojibiose. Thus, antibodies directed against the polyglycerophosphate chain, which is common to the lipoteichoic acids of many gram-positive species, and against the streptococcal group D antigen were obtained.

Chronic immune stimulation by sperm alloantigens. Support for the hypothesis that spermatozoa induce immune dysregulation in homosexual males

Putative, sperm-induced allogeneic immunization was correlated with immune dysregulation in a study of 30 asymptomatic, monogamously paired homosexual males. Evidence for allogeneic immunization existed among 19 of 26 homosexual males who were anal sperm recipients. No evidence for any form of alloimmunization was found in four exclusive sperm donors. Immune dysregulation in the form of a reduced effector/suppressor T-cell ratio (Te/Ts less than 1.0) was exclusively documented in eight anal-sperm-recipient homosexual males, five of whom also manifested evidence for allogeneic immunization. In three of those, immune dysregulation was further manifested by functional T-cell deficiency in the form of a subnormal (less than 50 cu mm) local graft-v-host reaction. Similar evidence for alloimmunization was associated with a reduced Te/Ts ratio (0.85) in the female of a heterosexual couple who routinely practiced anal intercourse. Based on these findings, we suggest that chronic, repeated exposure to sperm during anal intercourse results in a high frequency of allogeneic immunization and may play an important role in the development of acquired immune dysregulation among homosexual males.

Hyperdense renal masses: a CT manifestation of hemorrhagic renal cysts

Eleven patients with sharply circumscribed round to ovoid renal cysts measuring 70-90 H on CT are reported. The cysts were hyperdense on unenhanced scans, measuring 30-60 H greater than the adjacent parenchyma, and either hypodense, isodense, or hyperdense on enhanced scans. Four patients had polycystic kidney disease; of the other 7 patients, the cysts were cortical in 6 and parapelvic in 1. Eight patients had a solitary cyst and 3 had multiple cysts. Sonography demonstrated internal echoes and/or lack of increased through-transmission in 6 patients. Pathological analysis was available in 6 cases and indicated a benign, hemorrhagic renal cyst. This hyperdense CT appearance is characteristic of some hemorrhagic renal cysts, though differentiation between benign and malignant cysts requires cyst puncture and/or surgery.

Dissociation of iron transport and heme biosynthesis from commitment to terminal maturation of murine erythroleukemia cells

Treatment of murine erythroleukemia (MEL) cells with imidazole in the presence of dimethyl sulfoxide (Me2SO) has been shown to dissociate hemoglobin accumulation from commitment to terminal maturation. To explore the mechanism(s) of this effect, we studied iron transport and heme and hemoglobin synthesis in Me2SO-induced MEL cells that were then exposed to imidazole. Imidazole treatment (i) causes moderate inhibition of 125I-labeled transferrin binding to both control and Me2SO-treated MEL cells; (ii) markedly suppresses Me2SO-induced activation of iron uptake into MEL cells; (iii) markedly decreases the incorporation of iron into ferritin; and (iv) abolishes heme biosynthesis from [2-14C]glycine and hemoglobin accumulation in Me2SO-treated cells. Imidazole treatment does not inhibit other aspects of cellular maturation; cells treated with Me2SO in the presence or absence of imidazole exhibit similar changes in proliferative activity and protein synthesis and, as shown previously, in cell morphology. Inhibition of hemoglobin accumulation in MEL cells is reversible on withdrawal of imidazole but is not altered by exogenous hemin. These data indicate that commitment to terminal maturation is regulated independently from the systems for iron transport and heme biosynthesis during early phases of erythroid cell differentiation.

Dexamethasone-sensitive and -insensitive responses during in vitro differentiation of Friend erythroleukemia cells

We have investigated the mechanism(s) by which dexamethasone inhibit DMSO-induced Friend erythroleukemia cell differentiation in vitro. In particular, we examined the effects of dexamethasone on (a) the early events of differentiation such as cell volume alterations and 'memory response' and (b) the onset of biochemical events associated with terminal erythroid cell differentiation. By analysing kinetics of commitment of Friend cells to terminal erythroid differentiation on a clonal basis, we have observed that dexamethasone inhibited the completion of the latent period (time elapsed prior to commitment) and impaired "memory" (ability to inducer-treated cells to continue differentiation after a discontinuous exposure to inducer). Treatment of Friend cells with dexamethasone did not prevent the occurrence of DMSO-induced alterations in cell volume. However, dexamethasone treatment prevented a series of biochemical events associated with terminal Friend cell differentiation. These include the decrease in the rate of both cytoplasmic and nuclear RNA synthesis as well as the induction of cytidine deaminase activity and hemoglobin synthesis. These data indicate that the dexamethasone-sensitive process(es) operate during the early stages of Friend cell differentiation and that they are responsible for the inhibition of terminal erythroid maturation. These dexamethasone-sensitive processes, however, appear to be different from those regulating cell volume alterations during the early steps of DMSO-induced Friend cell differentiation.

Objective evaluation of local xenogeneic graft-versus-host reaction by computerized radioisotope imaging (CRI)

The local xenogeneic graft-versus-host reaction (GVHR) assay has been used clinically to evaluate cellular immune competence and experimentally to monitor the immunomodulatory effects of several drugs. By employing a computerized radioisotope imaging (CRI) technique, we were able to perform the assay with smaller numbers of mononuclear cells (MNC) and to rid it entirely of any bias. Measuring the local GVHR by CRI compares well with the conventional measurement of the volume (correlation coefficient r = 0.619; P less than 0.001). A clear-cut distinction was documented between normal donors and cancer patients (P less than 0.001) when 10 X 10(6) or more MNC were used in the assay. This is an improvement over the previous, conventional testing of local GVHR which required injection of 20 X 10(6) MNC in order to achieve a similar resolution. The indications for the presence of immune competence have therefore been redefined using the local GVHR index as determined by CRI according to the scale of MNC injected. Thus, immunocompetence is considered present if the CRI index is greater than or equal to 1.2 for 10 X 10(6) MNC, greater than or equal to 2.0 for 15 X 10(6) MNC and greater than or equal to 2.6 for 20 X 10(6) MNC.