Epstein-Barr virus-specific cytotoxic T lymphocytes as probes of HLA polymorphism. Heterogeneity of T cell-restricting determinants associated with the serologically defined HLA-A2 antigen.

Epstein-Barr (EB) virus-specific effector T cell lines were established from nine virus-immune donors positive for the serologically defined HLA-A2 antigen; of these, four lines contained a demonstrable A2-restricted cytotoxic component. When these four effector populations were each tested on the same panel of EB virus-transformed lines from 20 HLA-A2-positive individuals, 16 of the target cell lines were consistently killed at levels above 25% of the relevant autologous cell lysis. Cytotoxicity appeared to be mediated through a restricting determinant associated with the 'common A2' antigen that these lines shared; indeed the lysis could be specifically blocked by high concentrations of an HLA-A2-specific monoclonal antibody. In contrast, 4 out of 20 target cell lines were not killed by HLA-A2-restricted effector cells, even though they did express the serologically defined A2 antigen and were found in other tests to be susceptible to EB virus-specific cytolysis restricted through other HLA-A or -B antigens on their surface. These results suggest that EB virus-specific cytotoxic T cells can distinguish between serologically identical HLA-A2 molecules via the heterogeneity of their T cell-restricting determinants. Data from one of the effector cell populations further suggested that a serologically defined cross-reaction between the otherwise distinct HLA-A2 and -Bw57 antigens might also be reflected in a cross-reactivity of T cell-restricting determinants.

Cross-reactivity of self-HLA-restricted Epstein-Barr virus-specific cytotoxic T lymphocytes for allo-HLA determinants.

Epstein-Barr (EB) virus-specific cytotoxic T cells, prepared from virus-immune donors by reactivation in vitro and maintained thereafter as IL-2-dependent T cell lines, have been tested against large panels of EB virus-transformed lymphoblastoid cell lines of known HLA type. Whilst the pattern of lysis of the majority of targets was always consistent with HLA-A and HLA-B antigen restriction of effector function, in several cases it was noticed that certain HLA-mismatched targets were also reproducibly lysed. When this "anomalous" lysis was investigated in detail, it was found to be directed against allodeterminants on class I HLA antigens; thus, mitogen-stimulated as well as EB virus-transformed lymphoblasts from the relevant target cell donors were sensitive to the killing, and in each case the lysis could be specifically blocked by monoclonal antibodies to class I HLA antigens. In one example the target for this alloreactive lysis could be identified as a single serologically defined antigen, HLA-Bw57, while in another example lysis was directed against a "public" epitope common to HLA-Bw35, -Bw62, and a subset of -B12 antigens. Both cold target inhibition experiments and limiting dilution analysis strongly suggested that this alloreactive lysis was being mediated by the same effector T cells that recognize EB viral antigens in the context of self-HLA. This is the first demonstration in man that alloreactive responses can be derived from within the antigen-specific, self MHC-restricted T cell repertoire.

Morphological transformation in vitro of human fibroblasts by Epstein-Barr virus: preliminary observations.

Human embryo fibroblasts have undergone morphological transformation in vitro after infection by Epstein-Barr virus. The fibroblasts were maintained in suspension during exposure to the virus, and further treatment with inactivated Sendai virus increased the transformation rate. The transformed cells were large and polygonal and grew in discrete, heaped up, foci.

Individual tumors of multifocal EB virus-induced malignant lymphomas in tamarins arise from different B-cell clones.

Cotton-top tamarins were inoculated with sufficient Epstein-Barr virus to induce multiple tumors in each animal within 14 to 21 days. The tumors consisted of large-cell lymphomas that contained multiple copies of the Epstein-Barr virus genome and generated Epstein-Barr virus-carrying cell lines showing no detectable consistent chromosomal abnormality. Hybridization of tumor DNA with immunoglobulin gene probes revealed that each lymphoma was oligo- or monoclonal in origin and that individual tumors from the same animal arose from different B-cell clones. Thus the virus induced multiple transformation events in tamarins in vivo to cause malignant tumors resembling the Epstein-Barr virus-associated lymphomas of patients with organ transplants.

Implications of a vaccine for the prevention of Epstein-Barr virus infection: ethical and logistic considerations.

Reasons are given for considering that there is sufficiently substantial indirect and circumstantial evidence linking Epstein-Barr (EB) virus to African Burkitt's lymphoma (BL) and nasopharyngeal carcinoma to call for a dynamic new approach to establish a causal role for the virus in these human cancers. It would seem that the only way to do this would be to develop a vaccine, vaccinate a population at risk in a high-tumor-incidence area, and subsequently follow the population for a consequential decrease in tumor incidence. Recent developments in the control of animal herpesvirus-induced malignant tumors by vaccines free of viral nucleic acid make it possible to envisage that a similar vaccine could be developed against EB virus without undue difficulty. Experiments showing the tumor-inducing ability of EB virus in South American subhuman primates have provided an in vivo laboratory system in which to test the safety and efficacy of the vaccine. Trial of the vaccine in human populations could be carried out by testing its ability to protect those at risk from primary EB virus infection accompanied by infectious mononucleosis. Although in world terms BL is not a major health problem, nevertheless African BL provides uniquely favorable conditions in which to test for a causative role for EB virus: high incidence areas are known, the peak tumor incidence is at the age of 5 or 6, and the effects of vaccination on tumor incidence could be assessed within a decade. Should a carcinogenic role for EB virus be demonstrated in African BL, a much longer term program would be called for to extend the vaccine control of infection to areas where EB virus is implicated in the induction of nasopharyngeal carcinoma. Although a high incidence of this tumor is confined to populations of Southern Chinese origin, the very large numbers of such people and the frequency of the tumor among them make this a substantial world health problem and, therefore, worth the cost and effort necessary to develop a vaccine giving life-long immunity and to conduct a program that will take more than a generation to give positive results.

Congenital failure of automatic control of ventilation, gastrointestinal motility and heart rate.

A new congenital syndrome characterized by the simultaneous failure of control of ventilation (Ondine's curse) and intestinal motility (Hirschsprung's disease) is reported in three infants, all of whom died in the first few months of life; two were siblings. Detailed studies in one also revealed markedly decreased esophageal motility and abnormal control of heart rate. In one infant, minute ventilation was lower in quiet than in REM sleep and lower in both states of sleep than in wakefulness. Although the mean inspiratory flow was decreased in quiet sleep, the hypoventilation resulted primarily from a decrease in respiratory frequency. Intravenous doxapram increased ventilation but did not reverse respiratory failure. Aminophyllin, progesterone, physostigmine and chlorpromazine did not change ventilation significantly; imipramine resulted in a significant decrease. Both long and short-term variability of the heart rate were markedly decreased when compared with the normal infant. Although neuropathologic studies postmorten did not reveal an anatomic defect, we postulate that a developmental abnormality in serotonergic neurons is responsible for this new syndrome.

Cardiac rhythm during temporal lobe seizures.

We studied the neuroanatomic correlates of ictal tachycardia in 27 seizures from five patients with unilateral temporal lobe epilepsy being evaluated with bilateral temporal lobe depth electrodes and orbitofrontal subdural electrodes. There were 11 complex partial seizures, three simple partial seizures, and 13 subclinical seizures. For all seizures, heart rate (HR) increased in a graded fashion as new cortical regions anywhere in the brain were recruited into the seizure. HR plateaued at the new level despite EEG frequency changes until the next region became involved. Increases in HR did not correlate with increased duration of seizures but rather with volume of brain involved. Restricted amygdaloid seizure activity was generally insufficient to alter HR. We conclude that the amygdala has a limited role in modulating HR during seizures, and ictal tachycardia depends principally on the volume of cerebral structures recruited into a seizure.

Large-scale purification of Epstein-Barr virus membrane antigen gp340 with a monoclonal antibody immunoabsorbent.

A purification method has been elaborated to isolate Epstein-Barr (EB) virus membrane antigen, gp340, in milligram amounts. The gp340 was prepared from detergent extracts of B95-8 cells by affinity chromatography with a monoclonal antibody immunoabsorbent. Bound material was eluted and the eluate, consisting of 50% gp340, was then fractionated by gel filtration. The final gp340 product was antigenically active and 95% pure. The purification method was found to be rapid and reproducible with no loss of the ability of the immunoabsorbent to retain gp340 after repeated elution. The procedure provides suitable material to permit the detailed structural analysis of gp340 necessary for both vaccine design and for the investigation of the role of gp340 in immunity to EB virus infection.

Munchausen syndrome by proxy: considerations in diagnosis and confirmation by video surveillance.

Munchausen syndrome by proxy is a form of abuse in which the child suffers from a factitious illness induced by a parent. A case report of an 18-month-old boy who suffered from intractable diarrhea because of the surreptitious administration of laxatives by his mother is presented. The evolution of this case is discussed, as are the legal and ethical considerations in the diagnosis of Munchausen syndrome by proxy.

Selective reactivation of Epstein-Barr virus-specific cytotoxic T cells by stimulation in vitro with allogeneic virus-transformed HLA-homozygous typing cells.

Epstein-Barr (EB) virus-specific cytotoxic T-cell preparations, produced by stimulation in vitro of peripheral blood lymphocytes with the autologous virus-transformed cell line, are HLA-A and B antigen-restricted and, with some donors, show preferential restriction through one or two of the four relevant antigens of the donor's HLA type. It has now been demonstrated that such EB virus-specific cytotoxic T cells may also be reactivated by stimulation with allogeneic virus-transformed cells provided that there is no mismatch of the HLA-A and B antigens between the responder and stimulator cell donors. In particular, virus-transformed cell lines from HLA-homozygous donors HLA-A and B antigen-matched to one of the haplotypes of an HLA-heterozygous responder were shown to reactivate selectively only those EB virus-specific cytotoxic T cells restricted through the HLA-A and B antigens present on the allogeneic stimulating cells. In addition to confirming the polyclonal nature of the HLA-restricted EB virus-specific cytotoxic T-cell response, this new experimental procedure has allowed the production, and subsequent expansion as cell lines dependent upon T-cell growth factor, of those effector cells restricted through the "nonpreferred" HLA antigens that are poorly represented in the response induced by stimulation with autologous virus-transformed cells.

A highly sensitive enzyme-linked immunosorbent assay to quantitate antibodies to Epstein-Barr virus membrane antigen gp340.

An enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of antibodies to Epstein-Barr (EB) virus membrane antigen (MA) glycoprotein, gp340, in tamarins. The assay was found to be a thousand-fold more sensitive than conventional indirect immunofluorescence tests and consequently it was possible to follow accurately the sequential production of specific antibodies to gp340 by tamarins during a course of immunization.

A culture method giving substantial yields of normal nasopharyngeal epithelial cells for work with Epstein-Barr virus.

A culture method, utilising a feeder layer of lethally irradiated 3T3 fibroblasts and medium supplemented with hydrocortisone, cholera toxin, and epidermal growth factor, has been elaborated for the in vitro growth of normal human nasopharyngeal epithelial cells. This method allowed the cells to be grown in vitro for periods of up to 146 days, very considerably longer than in previously reported studies, and ensured that the cultures remained largely free from contaminating human fibroblasts. It was found possible to subculture the nasopharyngeal epithelial cells through numerous passages both by dispersing monolayers into single cell suspensions and by transferring coverslip monolayers of the cells to individual Petri dishes. By combining these two methods, at least 50 replicate epithelial cultures could be produced from each tissue sample, thus providing for the first time cultured nasopharyngeal epithelial cells in quantities suitable for extensive experiments with Epstein-Barr virus.

Quantification of an Epstein-Barr virus-associated membrane antigen component.

A method is described for the preparation of a 125I-labelled membrane antigen (MA) component (gp340) from B95-8 cell membranes using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Good yields of antigenic material were obtained when renaturation of the [125I]gp340 was carried out by removal of SDS in the presence of urea and subsequent removal of the urea. The availability of purified, radiolabelled gp340 has provided the essential basis for the development of a radioimmunoassay which, for the first time, permits quantification of this antigen. The assay has been used to demonstrate that cell membrane MA is a better source of gp340 for large-scale work than is the Epstein-Barr virus envelope and to measure the increase in expression of gp340 following treatment of cells with 12-O-tetradecanoyl-phorbol-13-acetate (TPA).

QTc interval prolongation associated with citalopram overdose: a case report and literature review.

Citalopram is a member of the selective serotonin reuptake inhibitor class of antidepressants. In 1998, citalopram was approved by the US Food and Drug Administration for the treatment of major depression. Like the other selective serotonin reuptake inhibitors, citalopram enjoys a relatively benign side effect profile compared with the tricyclic antidepressants and the monoamine oxidase inhibitors. However, citalopram has been associated with electrocardiographic changes and seizures at doses greater than 600 mg per day. Fatalities have occurred with citalopram-only overdoses. We report the case of a healthy 21-year-old woman who developed QTc interval prolongation after ingestion of approximately 400 mg citalopram. We discuss the cardiac effects of citalopram, review previous cases of citalopram overdose, and discuss treatment recommendations.

Reflections on Epstein-Barr virus: some recently resolved old uncertainties.

The change over recent decades in perceptions of the role of viruses in human cancer-causation is illustrated by the reception given to the discovery of Epstein-Barr virus (EBV) in 1964 compared to that of Kaposi's sarcoma herpesvirus (KSHV or HHV-8) in 1994. Very new data on EBV-like agents in New World monkeys is considered in relation to the antiquity of the association of proto-EBV with early anthropoids. Although the finding that individuals without B lymphocytes do not seem to be infected with EBV appears to have resolved the controversy regarding the permissive cell type producing infectious virus in the oropharynx, the presence of EBV in certain squamous and other epithelial cells raises continuing problems which are discussed. Among many recent successes of molecular biology applied to EBV, new information from such investigations on the genetic defect in X-linked lymphoproliferative syndrome now explains the cause of the disastrous pathological changes underlying the disease.Finally, current progress with vaccines against EBV is reviewed.

Cavernous angioma presenting as atypical facial and head pain.

Recurrent headache is a common pediatric problem. As the differential diagnosis of headache is extensive, physicians rely on the mode of presentation to focus any investigation. A report of an adolescent in whom atypical facial and head pain caused by a preexisting cerebellar cavernous angioma is presented. Facial pain and headache resolved following excision of the tumor.

Inhibition of rat mammary tumorigenesis by voluntary exercise.

In this study, the anti-promoting effect of voluntary (wheel) exercise on 7, 12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumorigenesis was investigated. All rats were fed high fat diets (23% of calories as fat) to mimice the typical western diet. Two doses of DMBA were used to determine if the antipromoting effects of exercise were dependent on the strength of the initiating agent. In addition, tumor estrogen receptors were assayed to determined whether exercise, through an estrogen-suppressing mechanism, selects for estrogen receptor-negative tumors. Female Sprague-Dawley rats were fed a semi-purified 23% fat (corn oil) diet (AIN-76A) and, on day 50 of age administered DMBA by gavage at 5 or 10 mg/rat. Rats were then randomized into 4 groups (n = 30) as follows: 1) low DMBA/sedentary; 2) low DMBA/exercise; 3) high DMBA/-sedentary; and 4) high DMBA/exercise. Active rats were placed in wheel-cage units, which allowed voluntary access to an activity wheel for 133 (low DMBA) and 77 (high DMBA) days, respectively, Sedentary rats were placed in conventional cages. Both active groups exhibited significantly lower total tumor numbers than their sedentary controls: 75 vs 102 (low DMBA) (p < 0.05) and 90 vs 160 (high DMBA) (p < 0.001). Compared to sedentary controls, latency was significantly lengthened in the low but not the high DMBA active groups; multiplicity, in contrast, was significantly decreased in the high, but not the low DMBA exercised group. Exercise had no effect on overall tumor incidence. When segregated into exercise tertiles, total tumor active compared to the least active tertile, particularly in the high DMBA group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma of the large bowel and colitis in captive cotton-top tamarins Saguinus o. oedipus.

The gross and microscopic appearance of large bowel adenocarcinoma in two young adult, captive-born cotton-top tamarins is described. A retrospective examination of sections of colons from other animals that had died in the colony revealed a high incidence of chronic colitis. The adenocarcinomas, which resembled those reported from colonies of this species in the U.S.A., are thought to be the first seen in Great Britain.

Memories of childhood sexual abuse: a survey of young adults.

OBJECTIVE: To explore the prevalence of, characteristics of, and factors associated with forgetting of childhood sexual abuse memories in a large non-clinical sample (N = 1712). METHOD: Using an anonymous survey, we asked respondents about (a) the nature and severity of their childhood abuse; (b) the continuity of their abuse memories; and (c) their experiences with others suggesting to them that they might have been abused. RESULTS: A substantial minority of victims in our sample reported having temporarily forgotten their childhood sexual abuse. Forgetting was largely unassociated with victim or abuse characteristics. Compared to individuals who always remembered their abuse, however, individuals who temporarily forgot were more likely to report that someone had suggested to them that they might have experienced abuse. Those who received such suggestions were particularly likely to suspect that they may have experienced childhood sexual abuse that they do not yet remember. CONCLUSION: Forgetting may be less common than implied by earlier estimates from clinical samples, yet it is not uncommon. Also, a sizable minority of the population is wondering whether they have experienced unremembered abuse, and these suspicions are linked to having encountered suggestions from others. We discuss the implications of these findings for understanding the phenomenon sometimes labeled repression.

Factors influencing population growth of a colony of cotton-top tamarins.

43% of full-term births in a colony of Saguinus oedipus oedipus occurred during April and May. Interbirth interval was usually 12 months in females which reared live young and 7 months in those whose young died perinatally. 81% of all full-term births were of twins, the rest were singles. High mortality among neonates was seen with a group of bought-in animals which had been taken from their parents at an early age without participating in the rearing of siblings, and was attributable to parental incompetence. Colony management aiming to ensure that animals gain experience in caring for young before breeding is described. Mortality among all animals older than 7 days was very low. Marginal protein deficiency may have been involved in a chronic diarrhoea and weight loss syndrome seen in some animals. They recovered after addition of hard-boiled egg to the diet.