Cyclin D1 provides a link between development and oncogenesis in the retina and breast

Mice lacking cyclin D1 have been generated by gene targeting in embryonic stem cells. Cyclin D1-deficient animals develop to term but show reduced body size, reduced viability, and symptoms of neurological impairment. Their retinas display a striking reduction in cell number due to proliferative failure during embryonic development. In situ hybridization studies of normal mouse embryos revealed an extremely high level of cyclin D1 in the retina, suggesting a special dependence of this tissue on cyclin D1. In adult mutant females, the breast epithelial compartment fails to undergo the massive proliferative changes associated with pregnancy despite normal levels of ovarian steroid hormones. Thus, steroid-induced proliferation of mammary epithelium during pregnancy may be driven through cyclin D1.

Cyclin D2 is an FSH-responsive gene involved in gonadal cell proliferation and oncogenesis

THE D-type cyclins (D1, D2 and D3) are critical governors of the cell-cycle clock apparatus during the G1 phase of the mammalian cell cycle. These three D-type cyclins are expressed in overlapping, apparently redundant fashion in the proliferating tissues. To investigate why mammalian cells need three distinct D-type cyclins, we have generated mice bearing a disrupted cyclin D2 gene by using gene targeting in embryonic stem cells. Cyclin D2-deficient females are sterile owing to the inability of ovarian granulosa cells to proliferate normally in response to follicle-stimulating hormone (FSH), whereas mutant males display hypoplastic testes. In ovarian granulosa cells, cyclin D2 is specifically induced by FSH via a cyclic-AMP-dependent pathway, indicating that expression of the various D-type cyclins is under control of distinct intracellular signalling pathways. The hypoplasia seen in cyclin D2(-/-) ovaries and testes prompted us to examine human cancers deriving from corresponding tissues. We find that some human ovarian and testicular tumours contain high levels of cyclin D2 messenger RNA.

Deletion of integrin alpha 1 by homologous recombination permits normal murine development but gives rise to a specific deficit in cell adhesion

Integrin alpha 1 is a receptor for laminin and collagen which is expressed widely and dynamically in embryogenesis and has been implicated in various developmental processes including establishment of the placenta and formation of the central and peripheral nervous system. In the adult it is the sole collagen receptor in smooth muscle and liver and is thought to be important for the stability of these tissues. We have generated a null allele of the alpha 1 gene in the germline of mice by homologous recombination in embryonic stem cells. Mice homozygous for the mutation are viable and fertile and have no overt phenotype, demonstrating that the molecule is not required for development. Embryonic fibroblasts derived from mutant animals are unable to spread on or migrate into substrata of collagen IV and are deficient in spreading on and migrating into laminin. Further in vitro analysis of cell spreading and migration suggests that alpha 1 beta 1 is not required for binding to collagen I and implicates a third receptor, possibly integrin alpha 3 beta 1, in collagen I binding.

Regulation of inflammation by collagen-binding integrins alpha1beta1 and alpha2beta1 in models of hypersensitivity and arthritis

Adhesive interactions play an important role in inflammation by promoting leukocyte attachment and extravasation from the vasculature into the peripheral tissues. However, the importance of adhesion molecules within the extracellular matrix-rich environment of peripheral tissues, in which cells must migrate and be activated, has not been well explored. We investigated the role of the major collagen-binding integrins, alpha1beta1 and alpha2beta1, in several in vivo models of inflammation. mAb's against murine alpha1 and alpha2 were found to significantly inhibit effector phase inflammatory responses in animal models of delayed-type hypersensitivity (DTH), contact hypersensitivity (CHS), and arthritis. Mice that were alpha1-deficient also showed decreased inflammatory responses in the CHS and arthritis models when compared with wild-type mice. Decreased leukocyte infiltration and edema formation accompanied inhibition of antigen-specific models of inflammation, as nonspecific inflammation induced by croton oil was not inhibited. This study demonstrates the importance in vivo of alpha1beta1 and alpha2beta1, the collagen-binding integrins, in inflammatory diseases. The study also extends the role of integrins in inflammation beyond leukocyte attachment and extravasation at the vascular endothelial interface, revealing the extracellular matrix environment of peripheral tissues as a new point of intervention for adhesion-based therapies.

Sensitivity to emotional expressions and situations in organic patients

While numerous lines of investigation indicate the pivotal role of the right hemisphere in the apprehension and processing of emotional information, the specific contributions of facial recognition, other visual-spatial capacities, and a general understanding of emotionally-toned situations remains to be delineated. To secure information on the contributions of these various factors, matched groups of brain-damaged patients were required in a series of tests to match with one another faces of the same individual, facial expressions, pictorial versions of emotional situations, and linguistic versions of emotional situations. While patients with left-hemisphere damage evinced special difficulty with linguistically-presented stimuli, patients with right hemisphere damage exhibited an across-the-board reduction in emotional sensitivity, one not restricted to stimuli presented in the visual modality. In addition, right hemisphere patients also displayed a selective tendency to group together emotions of an opposite polarity (positively-toned with negatively-toned emotions). These results suggest that, in addition to its general importance in a range of emotional tasks, the right hemisphere is crucial for an appreciation of the structural relations which obtain among various emotions.

Comprehension of humorous and nonhumorous materials by left and right brain-damaged patients

Right hemisphere-damaged (RHD) and left hemisphere-damaged (LHD) aphasic patients were tested on a nonverbal cartoon completion task that included a humorous (Joke) and a nonhumorous (Story) condition. In both conditions, RHD patients performed worse than LHD patients. More importantly, the qualitative difference between the errors produced by the two groups suggests that right and left hemisphere brain damage impairs different components of narrative ability. RHD patients showed a preserved sensitivity to the surprise element of humor, and a diminished ability to establish coherence. Conversely, LHD patients, when they erred, showed an impaired sensitivity to the surprise element of humor, and a preserved ability to establish coherence by integrating content across parts of a narrative. These results suggest that the observed humor comprehension deficits of RHD patients result specifically from right hemisphere disease and not from brain damage irrespective of locus. The performances of the RHD and LHD patients groups together support a separation of narrative ability from the traditional aspects of language ability typically disrupted in aphasia.

Comprehension and appreciation of humorous material following brain damage

The effects of brain damage on cognitive and affective status have been assessed separately; however, a dearth of information exists about the interaction of these facets in the brain-damaged patient. Because appreciation of humour involves both cognitive and affective dimensions, an investigation of response to humorous materials should yield information relevant to this issue. In addition, a study of response to humour in aphasic patients can reveal the extent to which appreciation of humour is dependent upon an intact language system. Accordingly a test of humour, in which an individual chose the "funniest" of four cartoons, was administered to a population of brain-damaged and control patients. Ability to detect the most humorous cartoon was impaired in all brain-damaged patients, more in severe than in mild aphasics, but there was no significant difference between patients with left and right hemisphere lesions in their overall performance on the test. A different order of difficulty across items, and a different profile of "mirth" responses to the items did, however, correlate with site of lesion. Right hemisphere patients tended either to laugh throughout or, more frequently, not at all; they often confabulated answers to made impossible inferences; and they performed better on items with captions. Their cognitive reactions appeared "dissociated" from their affective responses. In contrast left hemisphere patients performed better on the captionless items and behaved in a manner which more closely approximated normal subjects in their humorous reactions, their order of item difficulty, and their explanations. All brain-damaged patients found it relatively easier to locate the humorous cartoons when the members of a set differed appreciably from one another. These results provide information about the altered cognitive and affective states of brain-damaged patients, the impairment of cognitive operations in aphasic patients, and the respective "life-spaces" of left and right hemisphere injured patients.

Appreciation of metaphoric alternative word meanings by left and right brain-damaged patients

Appreciation of metaphoric and nonmetaphoric alternative word meanings was assessed in 19 aphasic, left (LHD) and 15 non-aphasic, right (RHD) hemisphere brain-damaged stroke patients. With the one exception in the aphasic group, all patients were male. In an unspeeded sorting task, subjects responded on the basis of less frequent, alternative meanings of polysemous target words. Targets were either polysemous adjectives (e.g. "warm") having metaphoric alternative meanings (loving) or polysemous nouns (e.g., "pen") having non-metaphoric alternative meanings (writing implement, cage). Both patient groups performed worse overall than a group of nonbrain-damaged control subjects. Relative to the RHD patients, LHD patients showed a spared appreciation of metaphoric alternative meanings. In addition, LHD, but not RHD, patients performed better on metaphoric adjective trials when there was high similarity between a word's dominant and (metaphoric) alternative meaning. The results suggest a pervasive insensitivity of RHD patients to alternative interpretations of linguistic units, and a special role for the intact right hemisphere in lexical-semantic processes related to metaphor comprehension.

Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients

Verbal humor deficits were investigated in right-hemisphere-damaged patients. It was hypothesized that the appreciation of jokes presupposes two elements: sensitivity to the surprise element entailed in the punch line of a joke and apprehension of the coherence which results when the punch line has been integrated with the body of the joke. The possible dissociation between these elements was tested by asking subjects to select from four alternatives the appropriate ending to a joke. Right-hemisphere patients exhibited a selective attraction to endings which contained an element of surprise but which were not otherwise coherent with the body of the joke. This finding suggests that right-hemisphere patients have difficulty in integrating content across parts of a narrative and confirms the psychological reality of the proposed distinction between the surprise and coherence elements of humor processing.

Integrin alpha1beta1 and transforming growth factor-beta1 play distinct roles in alport glomerular pathogenesis and serve as dual targets for metabolic therapy

Alport syndrome is a genetic disorder resulting from mutations in type IV collagen genes. The defect results in pathological changes in kidney glomerular and inner-ear basement membranes. In the kidney, progressive glomerulonephritis culminates in tubulointerstitial fibrosis and death. Using gene knockout-mouse models, we demonstrate that two different pathways, one mediated by transforming growth factor (TGF)-beta1 and the other by integrin alpha1beta1, affect Alport glomerular pathogenesis in distinct ways. In Alport mice that are also null for integrin alpha1 expression, expansion of the mesangial matrix and podocyte foot process effacement are attenuated. The novel observation of nonnative laminin isoforms (laminin-2 and/or laminin-4) accumulating in the glomerular basement membrane of Alport mice is markedly reduced in the double knockouts. The second pathway, mediated by TGF-beta1, was blocked using a soluble fusion protein comprising the extracellular domain of the TGF-beta1 type II receptor. This inhibitor prevents focal thickening of the glomerular basement membrane, but does not prevent effacement of the podocyte foot processes. If both integrin alpha1beta1 and TGF-beta1 pathways are functionally inhibited, glomerular foot process and glomerular basement membrane morphology are primarily restored and renal function is markedly improved. These data suggest that integrin alpha1beta1 and TGF-beta1 may provide useful targets for a dual therapy aimed at slowing disease progression in Alport glomerulonephritis.

Scavenging of reactive oxygen species by melatonin

The direct effects of the neurohormone melatonin on reactive oxygen species (ROS) were investigated. Melatonin was found to inhibit DMPO-O-2 formation in a dose-dependent manner. At the level of 1. 7+/-0.07 mM, melatonin caused 50% inhibition of EPR signal intensity of DMPO-O-2 during the reaction of xanthine and xanthine oxidase. The reaction rate constant of melatonin with O2- was found to be 1.25+/-0.07x103 M-1 s-1. However, melatonin (up to 1.2 mM) did not exhibit significant effect toward OH radical, produced by the Fenton reaction. In addition, we found no evidence for the formation of the melatonin indolyl cation radical that presumably precedes conversion of melatonin to its stable N1-acetyl-N2-5-methoxykynuramine (AMK) metabolite following sequential reactions of melatonin with O2- and OH. On the other hand, melatonin was capable of scavenging H2O2 in a dose-dependent manner with an IC50=0.5+/-0.02 mM. The reaction rate constant of melatonin with H2O2 was found to be 2.52+/-0.19x105 M-1 s-1. Furthermore, melatonin was also found to inhibit 1O2-dependent 2,2,6,6-tetramethylpiperidine oxide (TEMPO) radical formation during rose bengal photodynamic reaction. The results suggest that melatonin's antioxidant properties, in part, may involve a direct effect on scavenging of ROS.

Efficacy of everolimus (RAD001) in patients with advanced NSCLC previously treated with chemotherapy alone or with chemotherapy and EGFR inhibitors

BACKGROUND

Treatment options are scarce in pretreated advanced non-small-cell lung cancer (NSCLC) patients. RAD001, an oral inhibitor of the mammalian target of rapamycin (mTOR), has shown phase I efficacy in NSCLC.

METHODS

Stage IIIb or IV NSCLC patients, with two or fewer prior chemotherapy regimens, one platinum based (stratum 1) or both chemotherapy and epidermal growth factor receptor tyrosine kinase inhibitors (stratum 2), received RAD001 10 mg/day until progression or unacceptable toxicity. Primary objective was overall response rate (ORR). Analyses of markers associated with the mTOR pathway were carried out on archival tumor from a subgroup using immunohistochemistry (IHC) and direct mutation sequencing.

RESULTS

Eighty-five patients were enrolled, 42 in stratum 1 and 43 in stratum. ORR was 4.7% (7.1% stratum 1; 2.3% stratum 2). Overall disease control rate was 47.1%. Median progression-free survivals (PFSs) were 2.6 (stratum 1) and 2.7 months (stratum 2). Common > or =grade 3 events were fatigue, dyspnea, stomatitis, anemia, and thrombocytopenia. Pneumonitis, probably or possibly related, mainly grade 1/2, occurred in 25%. Cox regression analysis of IHC scores found that only phospho AKT (pAKT) was a significant independent predictor of worse PFS.

CONCLUSIONS

RAD001 10 mg/day was well tolerated, showing modest clinical activity in pretreated NSCLC. Evaluation of RAD001 plus standard therapy for metastatic NSCLC continues.

Absence of integrin alpha1beta1 in the mouse causes loss of feedback regulation of collagen synthesis in normal and wounded dermis

Integrin alpha1beta1 is a collagen receptor predominantly found in mesenchymal tissues. Mice lacking this receptor are viable. We have previously suggested that alpha1beta1 might participate in the down-regulation of collagen gene expression observed in cells suspended inside collagen gels. The results presented here demonstrate that integrin alpha1beta1 acts as a feedback regulator of collagen synthesis both in vitro and in vivo. Firstly, alpha1 null animals show a higher rate of collagen synthesis in the dermis in vivo. Secondly, fibroblasts derived from alpha1 null cutaneous wounds show a reduced sensitivity to collagen gel induced downregulation of collagen mRNA synthesis, as compared to their wild-type counterparts. An increase in collagenase synthesis is also seen in the alpha1 null dermis and in collagen gel suspended fibroblasts. While dermal thickness is normal in the alpha1 null animals, an increase is seen in skin thickness of alpha1 null but not alpha1 heterozygote animals on a background of collagenase resistant collagen. Increased expression of both collagen and collagenase mRNA are seen in experimental granulation tissue in alpha1 null animals, but their ultimate accumulation of collagen is normal, probably due to non alpha1 dependent paracrine regulators of collagen turnover.

A study of confabulation

Confabulation consequent to organic amnesia is a well-described clinical finding. A number of plausible theories of confabulation have been proposed, but the various claims and counterclaims have not been systematically tested. A standardized test battery that included four different kinds of questions plus measures of suggestibility and the tendency to utilize external cues was administered to ten amnesic patients who demonstrated varying degrees of confabulation. One additional patient, whose clinical condition changed dramatically during his hospital course, received the battery on a number of occasions. Differences among patients were found in overall performance, degree of confabulation, and ability to use cues. Hypothesized relationships between confabulation and suggestibility, degree of memory disorder, and degree of disorientation were not confirmed. However, confabulation proved to be strongly related to the inability to withhold answers, to monitor one's own responses and to provide verbal self-corrections. These results suggest a tentative model of the process of confabulation as well as a number of useful clinical signs indicationg recovery from amnesia.

Effect of antioxidant protection by p-coumaric acid on low-density lipoprotein cholesterol oxidation

Mechanisms in which p-coumaric acid (CA) acts as an antioxidant are not well understood. This study investigated whether CA can act as a direct scavenger of reactive oxygen species (ROS) and whether it minimizes the oxidation of low-density lipoprotein (LDL). Rats were administered CA in drinking water at low or high doses for 10, 21, and 30 days (uptakes were 29 and 317 mg/day, respectively). Blood levels of 8-epiprostaglandin F(2alpha) were monitored as a marker of LDL oxidation. Oral administration of CA (317 mg/day) for 30 days significantly inhibited LDL oxidation. CA also reduced LDL cholesterol levels in serum but had no effect on levels of high-density lipoprotein cholesterol. In vitro studies that used electron spin resonance in combination with spin trapping techniques were used to determine the ability of CA to scavenge ROS and alter LDL oxidation. CA effectively scavenged.OH in a dose-dependent manner. IC(50) and maximum velocity for CA scavenging of.OH were 4. 72 microM and 1.2 microM/s, respectively, with a rate constant of 1. 8 x 10(11) M(-1). s(-1). Our studies suggest that the antioxidant properties of CA may involve the direct scavenging of ROS such as.OH.

Reduplicative paramnesia

A striking behavioral abnormality is described in three individuals who had severe head trauma. At a point when general mnestic capabilities had returned to a near normal level, the patients persistently relocated the hospital at another geographical site, even in the face of compelling counter-evidence. The strong parallels in the etiology and course of the three cases justify the positing of a syndrome, here termed reduplicative paramnesia. A neuropsychologic analysis of the disorder stresses the cognitive operations entailed in geographical localization and confabulation. Clinical-pathologic considerations underline the role of right hemisphere and frontal lobe structures in the syndrome.

Zfx mutation results in small animal size and reduced germ cell number in male and female mice

The zinc-finger proteins ZFX and ZFY, encoded by genes on the mammalian X and Y chromosomes, have been speculated to function in sex differentiation, spermatogenesis, and Turner syndrome. We derived Zfx mutant mice by targeted mutagenesis. Mutant mice (both males and females) were smaller, less viable, and had fewer germ cells than wild-type mice, features also found in human females with an XO karyotype (Turner syndrome). Mutant XY animals were fully masculinized, with testes and male genitalia, and were fertile, but sperm counts were reduced by one half. Homozygous mutant XX animals were fully feminized, with ovaries and female genitalia, but showed a shortage of oocytes resulting in diminished fertility and shortened reproductive lifespan, as in premature ovarian failure in humans. The number of primordial germ cells was reduced in both XX and XY mutant animals at embryonic day 11.5, prior to gonadal sex differentiation. Zfx mutant animals exhibited a growth deficit evident at embryonic day 12.5, which persisted throughout postnatal life and was not complemented by the Zfy genes. These phenotypes provide the first direct evidence for a role of Zfx in growth and reproductive development.

Sensitivity to lexical denotation and connotation in brain-damaged patients: a double dissociation?

Sets of words can be grouped in terms of their denotation (cold and warm both refer literally to temperature) or in terms of their connotation (cold and warm connote remoteness and intimacy, respectively). To assess whether these two facets of meaning are dissociable, unilaterally left- and right-hemisphere-damaged patients were presented with word triads and asked to group together the two words that were closest in meaning. Right-hemisphere-damaged patients showed a preserved sensitivity to denotation, and a selective insensitivity to connotative facets of meanings. In contrast, left-hemisphere-damaged patients exhibited a preserved sensitivity to connotation as well as a selective insensitivity to denotative aspects of meanings. Inasmuch as normal control subjects displayed a flexible sensitivity to both denotative and connotative aspects of meaning, the results suggest that unilateral brain damage selectively curtails use of one or the other major aspect of word meaning.

Smad6 functions as an intracellular antagonist of some TGF-beta family members during Xenopus embryogenesis

BACKGROUND

Bone morphogenetic proteins (BMPs) transmit signals via the intracellular protein Smad1, which is phosphorylated by ligand bound receptors, translocates to the nucleus, and functions to activate BMP target genes. Recently, a subclass of Smad proteins has been shown to inhibit, rather than transduce, BMP signalling, either by binding to the intracellular domain of BMP receptors, thereby preventing phosphorylation-mediated activation of Smad1, or by binding directly to Smad1, thereby inhibiting its ability to activate gene transcription.

RESULTS

We have identified a Xenopus Smad (Smad6) that is 52% identical to mammalian Smad6, an inhibitory Smad. The spatial pattern of expression of Smad6 changes dynamically during embryogenesis and is similar to that of BMP-4 at the tailbud stage. Overexpression of Smad6 in Xenopus embryos phenocopies the effect of blocking BMP-4 signalling, leading to dorsalization of mesoderm and neuralization of ectoderm. Xenopus Smad6 completely blocks the activity of exogenous BMP-4, and, unlike human Smad6, partially blocks the activity of activin, in a mesoderm induction assay. We also find that Smad6 protein accumulates at the membrane in some cells but is partially or completely restricted to nuclei of most overexpressing cells.

CONCLUSIONS

We have identified an inhibitory Xenopus Smad, Smad6, that functions as an intracellular antagonist of activin and BMP-4 signalling. Our finding that Smad6 protein is partially or completely restricted to nuclei of most overexpressing cells suggests that it may employ a novel or additional mechanism of action to antagonize TGF-beta family signalling other than that reported for other inhibitory Smads.

The case against the case against group studies

We challenge the position that only the analysis of single patients can allow us to infer normal function from impaired performance. We claim that the focus on group vs. single case studies is unprofitable and that a more useful question is how best to form abstractions of relevance to cognitive theory. In this context, we consider issues concerning the category of "agrammatism."