Conservation of the WD-repeat, microtubule-binding protein, EMAP, in sea urchins, humans, and the nematode C. elegans.

The echinoderm microtubule-associated protein (EMAP) is the most abundant microtubule-binding protein in the first cleavage mitotic apparatus in sea urchin embryos. The first goal of this study was to determine whether there is sufficient EMAP in the egg and embryo to modify microtubule dynamics during the early cleavages divisions and whether EMAP functions at a specific time or place in the embryo. To accomplish this goal, we examined the relative abundance, tissue distribution, and temporal pattern of EMAP expression during embryonic development. The second goal of this study was to identify important functional domains within the EMAP coding sequence. A conserved sequence might reveal a potential microtubule-binding domain. We cloned, sequenced and compared overlapping EMAP cDNAs from two different sea urchin species that diverged approximately 80 million years ago, and compared these with cDNA sequences from a vertebrate and nematode species. From quantitative immunoblots, we determined the EMAP concentration in eggs to be 4 microM. The steady-state levels of EMAP mRNA and protein accumulated during development, and all three germ layers expressed EMAP. During the early stages of development, EMAP and tubulin were both abundant in the ectoderm, mesoderm and endoderm. However, during late gastrulation and the formation of the early pluteus larvae, EMAP was enriched in the mesoderm, while tubulin staining was most abundant in the archenteron. These results indicate that EMAP may have tissue-specific functions in the late stage embryo. To identify conserved functional domains, we compared the predicted amino acid sequence encoded by Strongylocentrotus purpuratus and Lytechinus variegatus EMAP cDNAs, and determined that these two sea urchin EMAPs were 95% conserved and shared an identical domain organization. A parsimonious analysis of these sea urchin protein sequences, as well as human and C. elegans EMAP sequences was used to construct a gene tree. Together these results suggest that EMAP is an important microtubule protein required at all developmental stages of sea urchins, and whose cellular function may be conserved amongst metazoans.

Trauma and the development of borderline personality disorder.

Prolonged and severe trauma, particularly trauma that occurs early in the life cycle, tends to result in a chronic inability to modulate emotions. When this occurs, people can mobilize a range of behaviors that are best understood as attempts at self-soothing. Some of these attempts include clinging and indiscriminate relationships with others in which old traumas are re-enacted over time, as well as more self-directed behaviors such as self-mutilation, eating disorders, and substance abuse. Usually, these behaviors will coexist. Patients with complicated trauma histories often repetitively attempt suicide or engage in chronic self-destructive behavior, and need to address issues of childhood trauma, neglect, and abandonment, both in the past and as re-experienced in current relationships. When treating these patients, therapists must anticipate that painful affects related to interpersonal safety, anger, and emotional needs may give rise to dissociative episodes, which may, in turn, be accompanied by increased self-destructive behavior. The therapy must clarify how current stresses are experienced as a return of past traumas and how small disruptions in present relationships are seen as a repetition of prior abandonment. As part of this, it is essential that the therapist provide validation and support, and avoid participating in a re-enactment of the trauma. Fear needs to be tamed in order for people to be able to think and be conscious of current needs. This bodily response of fear can be mitigated by safety of attachments, security of meaning schemes, and by a body whose reactions to environmental stress can be predicted and controlled. One of the great mysteries of the processing of traumatic experience is that as long as the trauma is experienced as speechless terror, the body continues to keep score and react to conditioned stimuli as a return of the trauma. When the mind is able to create symbolic representations of these past experiences, however, there often seems to be a taming of terror, a desomatization of experience. As Ducey and van der Kolk found in the Rorschachs of Vietnam veterans, patients were unresponsive to outside influences (good or bad) as long as they remained in a state of psychic numbing. Faced with intrusions of past trauma in their current emotional life, patients' initial sense of being overwhelmed was mastered only when a link between past trauma and current perceptions became understood.(ABSTRACT TRUNCATED AT 400 WORDS)

The history of trauma in psychiatry.

The accidental separation of PTSD and the dissociative disorders, based on the unfortunate fact that the PTSD and the dissociative disorder workgroups of the DSM-III never met to compare data, and the lack of knowledge within the workgroups of existing research connecting these disorders, will continue in the DSM-IV. That separation, however, is slowly being eroded by a solid body of research that shows that these conditions rarely occur independently. Thus, contemporary research is beginning to show that the original concept of "hysteria," formulated 150 years ago to capture a group of patients who have complex psychological and somatic problems and whose problems often elude intervention from the medical and psychological professions, is alive and well among patients on the verge of the twenty-first century. Although the DSM process has attempted to create cleaner diagnostic categories, 100 years of research on traumatized patients consistently shows that these patients defy easy classification, and that they seem to have symptoms that represent somatic, social, symbolic, and intrapsychic adaptations to having experienced overwhelming terror. Thus, what the DSM split when it abolished hysteria as a diagnosis, has once again been found to constitute a syndrome, a conglomeration of symptoms, first defined by Briquet and Janet more than 100 years ago, which is the result of severe and prolonged interpersonal abuse, usually starting in childhood. One hundred years of research has shown us that patients often cannot remember and, instead, re-enact their dramas. The professions ministering to these patients have had similar problems with remembering the past, and thrice in this century have forgotten the hard-earned lessons from our patients. It is not likely that these amnesias and dissociations will be a thing of the past; they are likely to continue as long as physicians and psychologists are faced, helplessly, with man's inhumanity to man.

Bombesin affects feeding independent of a gastric mechanism or site of action.

Peripherally administered bombesin has been demonstrated to inhibit food intake in a variety of species. Although the behavioral actions of bombesin are well characterized, neither the site of action nor mechanism through which bombesin affects feeding has been demonstrated. To test the hypothesis that bombesin's feeding effects are through a gastric inhibitory mechanism or a gastric site of action we examined the potential relationship between the inhibition of gastric emptying and the inhibition of intake produced across a dose range of bombesin and compared the relative potency of bombesin analogues for inhibiting feeding with their affinity for gastric bombesin receptors. Comparisons of the inhibitions of gastric emptying and feeding produced by 2, 4, 8, or 16 micrograms/kg of bombesin revealed no relationship, and, in fact, no gastric inhibitory action was evident. The feeding inhibitory actions of dose ranges (100 pmol-100 nmol) of litorin, ranatensin, acetylated gastrin-releasing peptide-(20-27) [AcGRP-(20-27)] and bombesin-(8-14) fragment were assessed and compared with bombesin. These compounds inhibited feeding with a relative potency of bombesin greater than AcGRP-(20-27) greater than ranatensin greater than litorin greater than bombesin-(8-14). This rank order of potency differed from the relative affinity of these compounds for gastric bombesin receptors for which all of these compounds except bombesin-(8-14) have a greater affinity than does bombesin. The results of these two experiments suggest that bombesin's satiety actions are not mediated by a gastric inhibitory mechanism or through a gastric site of action.

Pylorectomy reduces the satiety action of cholecystokinin.

Rat gastric cholecystokinin (CCK) receptors are localized to the circular muscle layer of the pyloric sphincter, and a role for these receptors in the mediation of CCK satiety has been proposed. To directly assess the contribution of this receptor population in CCK satiety, the area of the pyloric sphincter containing these receptors was surgically removed, and the behavioral responses to CCK were compared pre- and postpylorectomy. The presence of CCK receptors in the gastroduodenal junction was assessed by either in vitro CCK receptor autoradiography or in vitro contractile response to CCK. The results depended on the time after pylorectomy during which testing occurred. Two to 3 wk after pylorectomy rats demonstrated a significant attenuation of CCK satiety such that while the response to 1 and 2 micrograms/kg was intact, any additional inhibition by 4 and 8 micrograms/kg was eliminated. At this time, no evidence of CCK receptors around the gastroduodenal junction was found. In contrast, 2-3 mo after pylorectomy, the normal dose-response inhibition to CCK was intact. Evidence for the presence of CCK binding sites at the gastroduodenal junction was found by both autoradiography and physiological assessment. These results indicate a role for pyloric CCK receptors in the mediation of CCK satiety.

Distribution of bombesin binding sites in the rat gastrointestinal tract.

In an attempt to identify potential target sites for the satiety action of bombesin (BN), the distribution and pharmacological specificity of bombesin binding sites were examined in the rat gastrointestinal tract by in vitro autoradiography utilizing (125I-Tyr4) bombesin. Specific BN binding was localized to the circular muscle level of the gastric fundus and antrum, submucosal layer of the small intestine and longitudinal and circular muscle and submucosal layers of the colon. Pharmacological studies indicated that gastrin releasing peptide (GRP), Ac-GRP20-27 and BN-like compounds, litorin and ranatensin, inhibited the binding of (125I-Tyr4)BN with high affinity while compounds which lacked COOH-terminal homology with BN demonstrated a low affinity for BN binding sites. The wide distribution of BN binding sites in the gastrointestinal tract provides a number of potential sites for the mediation of the satiety action of BN.

Transport of cholecystokinin (CCK) binding sites in subdiaphragmatic vagal branches.

In order to evaluate vagal cholecystokinin (CCK) binding sites as potential target sites for the satiety actions of CCK, their presence, axonal flow and pharmacological specificity in subdiaphragmatic vagal branches were examined by autoradiography utilizing 125I-Bolton Hunter CCK-33. Specific CCK binding and axonal transport were found in vagal trunks and all abdominal vagal branches. Binding was inhibited by unlabelled CCK-8, but not by desulfated CCK-8. The pharmacological specificity and transport of CCK binding sites to subdiaphragmatic branches indicate a potential role in mediating CCK's satiety effect.