Targeted breakage of a human chromosome mediated by cloned human telomeric DNA.

Novel approaches to the structural and functional analysis of mammalian chromosomes would be possible if the gross structure of the chromosomes in living cells could be engineered. Controlled modifications can be engineered by conventional targeting techniques based on homologous recombination. Large but uncontrolled modifications can be made by the integration of cloned human telomeric DNA. We describe here the combined use of gene targeting and telomere-mediated chromosome breakage to generate a defined truncation of a human chromosome. Telomeric DNA was targeted to the 6-16 gene on the short arm of chromosome 1 in a human cell line. Molecular and cytogenetic analyses showed that, of eight targeted clones that were isolated, one clone had the predicted truncation of chromosome 1.

Very-low-dose streptozotocin induces diabetes in insulin promoter-mB7-1 transgenic mice.

Transgenic mice that express mouse B7-1 (mB7-1, recently designated CD80) on their pancreatic beta-cells maintain normal islet architecture, have normal pancreatic insulin content, and only rarely spontaneously develop insulitis and diabetes. Nevertheless, these mice display an extreme sensitivity to streptozotocin (STZ)-induced diabetes. Female mice were administered two STZ doses intraperitoneally, 20 and 40 mg/kg body wt, each for five consecutive days. Nontransgenic but otherwise syngeneic mice responded to the STZ with a moderate diminution in pancreatic insulin content but not with persistent glycosuria. In striking contrast, STZ administered to transgenic mice resulted in a severe diminution of pancreatic insulin content and in diabetes. Notably, the lower STZ dose resulted in diabetes only after a prolonged (26- to 100-day) latency. STZ-induced diabetes appears to be T-cell dependent, since treatment with T-cell-depleting (and in particular CD8+ subset-depleting) antibodies ameliorated the response. Anti-mB7-1 monoclonal antibody administration also prevented STZ-induced diabetes. Thus, unmasked mB7-1 is a required component in the pathway resulting in beta-cell killing. Immunohistological analysis revealed that early after STZ administration, both mB7-1 transgenic and nontransgenic mice developed insulitis. While this insulitis resolved in the nontransgenic mice, the islet-infiltrating CD4+ and CD8+ T-cells in the transgenic mice were associated with complete beta-cell destruction. These data suggest that STZ-induced diabetes in mB7-1 transgenic mice is an immune-mediated process with distinct potential advantages over existing insulin-dependent diabetes models.

T helper lymphocyte depression in early human pregnancy.

Peripheral blood lymphocyte subclasses were determined in 60 women with normal pregnancies, 20 from each trimester, and in 20 controls using automated flow cytofluorimetry. The cells were stained with the monoclonal antibodies OKT3, OKT4 and OKT8 to stain total T cells, T helper and T suppressor-cytotoxic lymphocytes, respectively. A polyvalent rabbit anti-human Ig serum was used to stain B lymphocytes. Absolute numbers of T lymphocytes were significantly reduced in both the first and second trimesters. This was due to a significant decrease in T helper lymphocytes and a smaller, statistically not significant, reduction in the number of T suppressor lymphocytes. There was no significant change in lymphocyte subclasses during the third trimester. Total lymphocyte numbers were normal throughout pregnancy.

Empathy with a rape victim: the role of similarity of experience.

The purpose of this study was to replicate and extend a prior investigation (Barnett, Tetreault, Esper, & Bristow, 1986) in order to clarify the role of similarity of experience in women's empathy with a rape victim. Women who were identified as having been raped rated themselves as more empathic with, and more similar to, a rape victim patient presented on videotape than did nonrape control subjects who had been matched on level of dispositional empathy. However, no difference was found between the two subject groups in their responses to a videotaped patient whose personal problems were unrelated to the experience of rape. In addition, subjects generally rated the rape victim patient as less emotionally stable than the patient whose personal problems were unrelated to rape. Alternative interpretations of the major finding of this study are discussed.

Influence of the reason for the other's affect on preschoolers' empathic response.

Forty-six preschoolers were individually presented four slide-sequence stories in which the main character performed acts that resulted in the character displaying happiness (in two stories) or sadness (in two stories). Within each happy and sad story pair, one story portrayed the main character as having an "acceptable" reason for his or her affect (e.g., the character was happy after finding a friend to play with) and one story portrayed the character as having an "unacceptable" reason for his or her affect (e.g., the character was happy after transgressing against another child). Affective and evaluative responses to the main characters in the four stories were assessed. The preschoolers generally empathized more with (and evaluated more favorably) a story character whose affect was associated with the performance of an acceptable rather than an unacceptable act.

The relation of distressful childhood experiences and empathy in college undergraduates.

We assessed the relation between the empathic responsiveness of young adults and the relative frequency and intensity of distressful events they experienced as children. Undergraduate subjects (N = 111; 56 men and 55 women) were led to believe that they were participating in two separate studies. In the first study, students completed the Distress Experiences in Childhood questionnaire, a filler task, and a slightly abbreviated version of the Mehrabian and Epstein (1972) empathy measure. In the second study, students watched an emotion-laden videotape of a patient (actually an actress) in a therapy session and subsequently completed an emotional-response questionnaire adapted from Batson, O'Quin, Fultz, Vanderplas, and Isen (1983). Students who rated their distressful childhood experiences as highly distressing scored higher on both measures of empathy than did students who rated their experiences as relatively less distressing. In contrast, the number of distressful childhood experiences reported was generally unrelated to empathy scores.

Factors affecting children's adolescents', and young adults' perceptions of parental discipline.

A total of 663 second graders, sixth graders, high school students, and college undergraduates were shown three videotapes depicting a mother's or father's reaction to a daughter or son who had treated peers unkindly. Although the participants generally favored induction over power assertion and love withdrawal, their perceptions of the particular discipline techniques were found to be influenced by their gender and age, as well as the genders of the child-transgressor and parent-disciplinarian. In addition, the evaluation of a given discipline technique (and, among the older participants, the reported intention of using this technique with their own son or daughter in the future) was found to be related to participants' reports of the extent to which their own parents had used the same technique.

Factors affecting reactions to a rape victim.

We examined the influence of the sex of the subject reacting to the rape victim, the type of rape (stranger vs. acquaintance), the location of the rape (inside vs. outside the victim's home), and the victim's attribution concerning the cause of the rape, on undergraduates' reactions to a rape victim. American undergraduates (264 women, 230 men) read a Rape Crisis Center Intake Form, watched a videotape of a rape victim (an actress) describing her psychological and behavioral reactions to the rape, and completed three questionnaires assessing their reactions to the victim. Women were more supportive of the rape victim than were men, and the stranger rape evoked more chance and characterological attributions than did the acquaintance rape. A rape outside the home evoked more chance attributions than did an "inside" rape. The rape victim was rated as having been more traumatized by the experience if she made any causal attribution than if she made no attribution at all.

Correlates of reminiscence activity among elderly individuals.

The purpose of this study was to examine several psychological characteristics and life experiences that may be related to aspects of reminiscence activity among elderly individuals. Seventy elderly individuals completed a reminiscence questionnaire assessing 1) the extent to which reminiscence is motivated by a desire to enhance self understanding, 2) reminiscence affect, and 3) the preferred social modality of reminiscence. The respondents also completed questionnaires assessing existential vacuum, extraversion, and the recent experience of various life events. Existential vacuum was positively associated with a tendency to engage in reminiscence in an effort to enhance self understanding as well as a negative bias in reminiscence affect. Extra-version was found to be positively related to a preference for interpersonal reminiscence. Specific life experiences (e.g., death of a spouse, retirement) were also related to reminiscence activity. The present results provide support for the notion that aspects of reminiscence activity are associated with individual differences in specific psychological and situational variables.

Adolescents' evaluations of Peers' motives for helping.

Four groups of high-school students (N=92) were each informed about a pair of helpers, either male or female, who independently helped a sameor opposite-sex peer. Within each pair of same-sex helpers, one was presented as having helped for empathic reasons and the other was presented as having helped for nonempathic reasons. The adolescents' ratings of the helpers indicated that they generally favored empathically motivated helping in both male and female peers. However, a female helper who did not express sensitivity and emotional responsiveness to the feelings of the needy other in her prosocial moral reasoning tended to be judged more harshly by the adolescents than did a male helper who failed to express such sentiments.

T lymphocyte subset abnormalities and HLA antigens in scleroderma (systemic sclerosis).

Studies of T lymphocyte subsets were carried out in a group of 50 scleroderma patients, of whom 46 were also HLA phenotyped. The total lymphocyte count was depressed in 22 patients, and CD4 (helper cells) numbers were normal. CD8 (suppressor-cytotoxic) cells were reduced in 27 patients, and the CD4/CD8 number ratio increased above normal in three additional patients, resulting in 30 patients being classified as CD8-deficient. In the 46 patients HLA phenotyped, DRw8 was significantly increased in the entire patient group, but when the patients were subdivided into CD8-deficient (n = 29) and CD8-normal (n = 17), the increase in DRw8 was confined to the CD8-deficient patients. B18 was also increased in patients with limited sclerosis, while DR4 and DRw53 were significantly decreased and DR5 significantly increased in patients with more extensive skin sclerosis. These findings suggest that scleroderma is a heterogeneous condition and that this heterogeneity is reflected in different HLA profiles in patients subtyped according to their clinical profile and subpopulations of T cells.

Lymphocyte subclasses in pregnancy induced hypertension.

Peripheral blood lymphocyte subclasses were studied by flow cytofluorimetry and monoclonal antibodies in 21 women with Pregnancy Induced Hypertension (PIH), 20 healthy women in their third trimester of pregnancy and in 20 nulliparous, nonpregnant women. The cells were stained with the monoclonal antibodies OKT3, OKT4 and OKT8 to define total T cells, T helper cells (Th) and T suppressor-cytotoxic cells (Ts/c) respectively. B lymphocytes were defined by their surface immunoglobulin. Absolute numbers of total T cells and Ts/c cells were significantly decreased (p less than 0.05) in patients with PIH compared to either control group. The proportion of B lymphocytes was significantly (p less than 0.01) increased and absolute numbers were marginally increased. These findings reflect an immune disturbance which may be of prime importance in the pathogenesis of this disease.

Dissecting the centromere of the human Y chromosome with cloned telomeric DNA.

We have used telomeric DNA to break the human Y chromosome within the centromeric array of alphoid satellite DNA and have created two derivative chromosomes; one consists of the short arm and 140 kb of alphoid DNA, the other consists of the long arm and 480 kb of alphoid DNA. Both segregate accurately at mitosis. It is known that there is no large scale sequence duplication around the alphoid DNA and so the simplest interpretation of our results is that the sequence responsible for accurate segregation is the alphoid DNA itself. Although the long arm acrocentric derivative segregates accurately it lags with respect to the other chromosomes in about 10% of anaphase cells and thus additional sequences may be required for orderly segregation. The short arm acrocentric chromosome is probably no larger than 12 Mb in size and thus our results also demonstrate that chromosomes of this size are capable of accurate segregation.

Altered blood lymphocyte subclasses in patients with ulcerative colitis.

Peripheral blood lymphocytes were studied by flow cytofluorimetry and monoclonal antibody techniques in 107 patients with ulcerative colitis and in 20 healthy controls of similar ages. Total T, T helper (TH), and T cytotoxic/suppressor (TC/S) lymphocytes were defined by the monoclonal antibodies OKT3, OKT4 and OKT8, respectively, while B lymphocytes were defined by surface immunoglobulin. Patients had a significantly (P less than 0.05) lower proportion of TC/S lymphocytes than the controls, and patients with quiescent disease had a reduced proportion of B lymphocytes compared to controls and those with active disease. Patients with marked mucosal dysplasia had a significantly (P less than 0.025) lower proportion of TH lymphocytes and a higher (P less than 0.01) proportion of B lymphocytes than those without dysplasia. There were no significant associations between lymphocyte levels and any other clinicopathological features assessed.

Telomere directed fragmentation of mammalian chromosomes.

Cloned human telomeric DNA can integrate into mammalian chromosomes and seed the formation of new telomeres. This process occurs efficiently in three established human cell lines and in a mouse embryonic stem cell line. The newly seeded telomeres appear to be healed by telomerase. The seeding of new telomeres by cloned telomeric DNA is either undetectable or very inefficient in non-tumourigenic mouse or human somatic cell lines. The cytogenetic consequences of the seeding of new telomeres include large chromosome truncations but most of the telomere seeding events occur close to the pre-existing ends of natural chromosomes.

Changes in lymphocyte status and responsiveness in pregnancy detected by a fluorescent cell probe.

Lymphocyte reactivity assessed by a fluorescent lipophilic probe test of responsiveness to concanavalin A (con A) was shown to differ from normal in early pregnancy. The difference was most marked in multiparas. Abnormal reactivity was detected in the earliest pregnancy examined (5 weeks' gestation) and up to about the 20th week; after 20 weeks, reactivity was normal in all of the multiparas and most of the nulliparas studied. However, in pregnancy induced hypertension (PIH), a disorder of late pregnancy, the same responsiveness as in early pregnancy was found. When unstimulated lymphocytes were examined, abnormal reactivity associated with increased fluorescence was observed in early pregnancy and in PIH, compared with normal late pregnancy, reflecting alteration in lymphocyte membrane phospholipids. It is postulated that pregnancy is associated with sequential change in immunity, disturbance of which may result in immunologically-determined obstetric morbidity.