Stability of hippocampal subfield volumes after trauma and relationship to development of PTSD symptoms.

BACKGROUND: The hippocampus plays a central role in post-traumatic stress disorder (PTSD) pathogenesis, and the majority of neuroimaging research on PTSD has studied the hippocampus in its entirety. Although extensive literature demonstrates changes in hippocampal volume are associated with PTSD, fewer studies have probed the relationship between symptoms and the hippocampus' functionally and structurally distinct subfields. We utilized data from a longitudinal study examining post-trauma outcomes to determine whether hippocampal subfield volumes change post-trauma and whether specific subfields are significantly associated with, or prospectively related to, PTSD symptom severity. As a secondary aim, we leveraged our unique study design sample to also investigate reliability of hippocampal subfield volumes using both cross-sectional and longitudinal pipelines available in FreeSurfer v6.0. METHODS: Two-hundred and fifteen traumatically injured individuals were recruited from an urban Emergency Department. Two-weeks post-injury, participants underwent two consecutive days of neuroimaging (time 1: T1, and time 2: T2) with magnetic resonance imaging (MRI) and completed self-report assessments. Six-months later (time 3: T3), participants underwent an additional scan and were administered a structured interview assessing PTSD symptoms. First, we calculated reliability of hippocampal measurements at T1 and T2 (automatically segmented with FreeSurfer v6.0). We then examined the prospective (T1 subfields) and cross-sectional (T3 subfields) relationship between volumes and PTSD. Finally, we tested whether change in subfield volumes between T1 and T3 explained PTSD symptom variability. RESULTS: After controlling for sex, age, and total brain volume, none of the subfield volumes (T1) were prospectively related to T3 PTSD symptoms nor were subfield volumes (T3) associated with current PTSD symptoms (T3). Tl - T2 reliability of all hippocampal subfields ranged from good to excellent (intraclass correlation coefficient (ICC) values > 0.83), with poorer reliability in the hippocampal fissure. CONCLUSION: Our study was a novel examination of the prospective relationship between hippocampal subfield volumes in relation to PTSD in a large trauma-exposed urban sample. There was no significant relationship between subfield volumes and PTSD symptoms, however, we confirmed FreeSurfer v6.0 hippocampal subfield segmentation is reliable when applied to a traumatically-injured sample, using both cross-sectional and longitudinal analysis pipelines. Although hippocampal subfield volumes may be an important marker of individual variability in PTSD, findings are likely conditional on the timing of the measurements (e.g. acute or chronic post-trauma periods) and analysis strategy (e.g. cross-sectional or prospective).

Lipopolysacchride-treated mammary carcinomas secrete proinflammatory chemokines and exhibit reduced growth rates in vivo, but not in vitro.

Toll-like receptors (TLR) are pattern recognition receptors that play a pivotal role in the initiation of immune responses. Here we report that the murine mammary carcinoma 4T1 constitutively expressed genes encoding TLR2, 3, 4 and 5. Moreover, treatment of the 4T1 cell line with peptidoglycan (PGN), polyinosinic-polycytidylic acid (Poly(I:C)) or lipopolysaccharide (LPS), agonists for TLR2, 3 or 4 respectively, induced nuclear translocation of NFkappaB and secretion of CCL2, CCL5 and CXCL1 in a dose dependent manner. Although treating the tumor cells with the TLR agonists did not modulate growth or viability of the tumor cells in vitro, 4T1 exhibited a decreased growth rate in vivo following treatment with LPS that was dependent upon the presence of CD8(+) T cells. Analysis of 3 additional murine mammary carcinomas revealed that they also secreted CCL2, CCL5 and CXCL1 in response to TLR agonist treatment, and LPS treated 168 and SM1 tumors exhibited decreased growth rates in vivo, but not in vitro. These data indicated that 4 out of 4 murine mammary carcinomas secreted proinflammatory chemokines following treatment with TLR agonists, and 3 out of 4 of the mammary carcinomas responded to LPS treatment in a manner that decreased tumor growth in vivo.

Complete nucleotide sequence of the 27-kilobase virulence related locus (vrl) of Dichelobacter nodosus: evidence for extrachromosomal origin.

The vrl locus is preferentially associated with virulent isolates of the ovine footrot pathogen, Dichelobacter nodosus. The complete nucleotide sequence of this 27.1-kb region has now been determined. The data reveal that the locus has a G+C content much higher than the rest of the D. nodosus chromosome and contains 22 open reading frames (ORFs) encoding products including a putative adenine-specific methylase, two potential DEAH ATP-dependent helicases, and two products with sequence similarity to a bacteriophage resistance system. These ORFs are all in the same orientation, and most are either overlapping or separated by only a few nucleotides, suggesting that they comprise an operon and are translationally coupled. Expression vector studies have led to the identification of proteins that correspond to many of these ORFs. These data, in combination with evidence of insertion of vrl into the 3' end of an ssrA gene, are consistent with the hypothesis that the vrl locus was derived from the insertion of a bacteriophage or plasmid into the D. nodosus genome.

Probing the structure of the nicotinic acetylcholine receptor with the hydrophobic photoreactive probes [125I]TID-BE and [125I]TIDPC/16.

The hydrophobic photoreactive compound 3-trifluoromethyl-3-(m-[125I]iodophenyl) diazirine ([125I]TID) has revealed important structural information about the pore of the ion channel and lipid-protein interface of the nicotinic acetylcholine receptor (AChR). To further characterize the structure of the AChR, we have mapped the sites of photoincorporation of a benzoic acid ester analogue of TID ([125I]TID-BE) and a phospholipid analogue ([125I]TIDPC/16). For each photoreactive probe, labeled sites were identified by amino-terminal sequencing of purified tryptic fragments of individual receptor subunits. [125I]TID-BE reacted with alphaCys-412, alphaMet-415, and alphaCys-418 in the M4 segment of the alpha-subunit and gammaCys-451 and gammaSer-460 in gammaM4. In the M1 segment of the alpha- and beta-subunits, [125I]TID-BE labeled alphaPhe-227, alphaLeu-228, and betaLeu-234, betaAla-235, respectively. The labeling pattern in the M1 and M4 segments indicate that TID and TID-BE interact with the AChR lipid-protein interface in a similar fashion, revealing the same lipid-exposed face of each transmembrane segment. In contrast to TID, there was, however, no detectable incorporation of [125I]TID-BE into the channel lining betaM2 segment when the AChR was labeled in the resting state conformation. In the presence of agonist (desensitized state), [125I]TID-BE reacted with betaLeu-257, betaVal-261, and beta-Leu-264 in betaM2; a labeling pattern which indicates that, in comparison to TID, the binding loci for TID-BE is located closer to the extracellular end of the channel. For [125I]TIDPC/16, receptor labeling was insensitive to the presence of agonist and the sites of incorporation mapped to the confines of the transmembrane segments alphaM4, alphaM1, and gammaM4, validating previous results found with small lipophilic probes.

Chloramphenicol resistance in Clostridium difficile is encoded on Tn4453 transposons that are closely related to Tn4451 from Clostridium perfringens.

The chloramphenicol resistance gene catD from Clostridium difficile was shown to be encoded on the transposons Tn4453a and Tn4453b, which were structurally and functionally related to Tn4451 from Clostridium perfringens. Tn4453a and Tn4453b excised precisely from recombinant plasmids, generating a circular form, as is the case for Tn4451. Evidence that this process is mediated by Tn4453-encoded tnpX genes was obtained from experiments which showed that in trans these genes complemented a Tn4451tnpX delta 1 mutation for excision. Nucleotide sequencing showed that the joint of the circular form generated by the excision of Tn4453a and Tn4453b was similar to that from Tn4451. These results suggest that the Tn4453-encoded TnpX proteins bind to similar DNA target sequences and function in a manner comparable to that of TnpX from Tn4453. Furthermore, it has been shown that Tn4453a and Tn4453b can be transferred to suitable recipient cells by RP4 and therefore are mobilizable transposons. It is concluded that, like Tn4451, they must encode a functional tnpZ gene and a target oriT or RSA site. The finding that related transposable elements are present in C. difficile and C. perfringens has implications for the evolution and dissemination of antibiotic resistance genes and the mobile elements on which they are found within the clostridia.

Delineation of the virulence-related locus (vrl) of Dichelobacter nodosus.

Dichelobacter nodosus is the primary pathogen implicated in ovine footrot. In this paper we have delineated a 27 kb locus, termed the virulence-related locus (vrl), that was essentially specific for virulent D. nodosus isolates. The precise ends of this locus were mapped and the sequences of the junction regions from the virulent strain A198 were compared to corresponding sequences from the benign isolate C305. The left end of the vrl locus was located in a sequence similar to that of the small stable 10Sa RNA molecule of Escherichia coli, next to a phage-attachment-site-like sequence, which indicated that the vrl locus might have arisen by the integration of a phage. However, no attachment-like sequence could be found at the right end of the vrl locus. In the chromosome of the benign strain the sequences bordering vrl were not contiguous but were separated by about 3 kb. It was concluded that the divergence of the benign and virulent strains at this locus was a multi-step process. Several potential ORFs were identified at the junction regions but only one ORF, encoding a 126 kDa protein, was expressed in a T7 expression system in E. coli.

Comparative sequence analysis of the catB gene from Clostridium butyricum.

Sequence analysis of the Clostridium butyricum chloramphenicol acetyltransferase (CAT) gene, catB, showed that it encoded a CAT monomer of 219 amino acids with a molecular weight of 26,114. Comparison of the deduced amino acid sequence of the CATB monomer to those of sixteen other CATs showed that it was most closely related to the CATQ monomer from Clostridium perfringens.

Assessment of non-palpable mammographic abnormalities: comparison between screening and symptomatic clinics.

A retrospective study found that a breast screening clinic generated fewer localization biopsies for non-palpable mammographic abnormalities than a symptomatic clinic (3.36 versus 9.89 per 1000 mammograms, respectively) and that a greater proportion of such biopsies were malignant. This study determined the reason for this difference. There were 108 of 304 (35.5 per cent) and 17 of 130 (13.1 per cent) carcinomas in women attending the screening and breast clinics respectively (relative risk 2.72 (95 per cent confidence interval 1.70-4.34)). This difference was regardless of age. The characteristics of the mammographic abnormality, the Wolfe pattern, a family history of breast carcinoma, parity and age at first pregnancy were similar in both groups. Women attending the screening clinic were referred for localization biopsy after assessment by clinicians and radiologists at a joint clinic; there was no joint assessment for patients attending the breast clinic. The same staff attended both clinics, although the proportion of time spent at each varied. This study suggests that all women with a non-palpable mammographic abnormality should be reviewed at a joint assessment clinic before localization biopsy is recommended.

Comparative pathology of breast cancer in a randomised trial of screening.

In the Edinburgh Randomised Breast Screening Project (EBSP) to December 1988 there were 500 cancers in the study population invited to screening and 340 cancers identified in the control population. The size and negative lymph node status characteristics of invasive cancers from the two populations were significantly different (P less than 0.05). The cancers detected by screening were predominantly 'early stage', with 16% noninvasive (PTIS) and 42% invasive stage I (pT1 node negative), whereas cancers were frequently 'late stage' (more than pT2) and inoperable in nonattenders (44%) and controls (36%). Grouped according to customary size ranges of invasive cancers, the proportion of cases lymph node positive differed in those screen detected compared with controls, but the benefit in favour of screen detection was not constant. In comparisons of cancers detected at prevalence and incidence screens, as a test of conformity with screening theory, no significant differences were apparent according to size and lymph node status, yet the characteristics of histological type of cancer discriminated significantly (P less than 0.05). When these same histological characteristics were used to compare survival, the capacity to separate invasive cancers into two groups having good and poor survival probabilities was evident, with a significant improvement for the screen detected poor survival group compared with controls (P less than 0.05).

Edinburgh trial of screening for breast cancer: mortality at seven years.

Between 1979 and 1981, 45,130 women in Edinburgh aged 45-64 were entered into a randomised trial of breast cancer screening by mammography and clinical examination. The initial attendance rate was 61% but this varied according to age and socioeconomic status and decreased over succeeding years. The cancer detection rate was 6.2 per 1000 women attending at the first visit; the rate fell to around 3 per 1000 in the years when mammography was routinely repeated and to around 1 per 1000 at the intervening visits with clinical examination alone as the screening method. After 7 years of follow-up the mortality reduction achieved was 17% (relative risk = 0.83, 95% CI 0.58-1.18), which was not statistically significant, even when corrected for socioeconomic status. In women aged 50 years and over a mortality reduction of 20% was achieved.

An enriched set of features of nuclear cataract identified by multidimensional scaling.

Development of an improved system for visual classification of cataracts requires a three-step procedure: first, to identify the full range of visible features of cataracts; second, to develop and test scales for the visual assessment of each feature; and third, to establish the epidemiological or clinical validity of each scale for cataract classification. This paper focuses on the first step, applying a powerful psychometric technique for identifying the visible features of nuclear cataracts. New visual features of nuclear cataract were identified using the psychometric procedure of multidimensional scaling (MDS). Each of 5 observers independently examined pairings of slitlamp photographs of 24 cases of pure nuclear cataract, making two different ratings of dissimilarity of each of the 276 possible pairs. The two dissimilarity ratings were, first, of nuclear color and, second, of nuclear structure. MDS analysis of the dissimilarity ratings of nuclear color revealed two major visual features underlying the judgments: one a combination of hue and saturation, and the other brightness. Analysis of the ratings of nuclear structure identified a total of nine features: one distinguishing between immature and mature cataracts, four describing features of the immature cataracts (aspect ratio, background haze, clarity of the embryonal nucleus, and clarity of the outer nuclear shell), and four describing features of the mature cataracts (opalescence, aspect ratio, color of the nucleus, and symmetry). We conclude that there are many more systematic distinctions to be made in the appearance of nuclear cataracts than are now recognized in clinical practice.

Use of risk factors to allocate schedules for breast cancer screening.

In an effort to reduce the cost of breast cancer screening several studies have explored the possibility of using risk factors to select a high-risk group of women and then restrict screening to that group. The results of these studies have been almost entirely negative and so it is not possible at present to classify any woman as at such low risk that she need not be screened. Nevertheless it is well known that some groups of women can be identified as being at higher risk than the general population. In this study it is assumed that each woman will be offered one screen at which risk factor information will be collected. The usual screening policy is then one of uniform intervention in which the interval to the next screen is the same for all women: the interval that is currently recommended in the UK is three years. An alternative is a risk strategy in which the time to the next screen depends on the woman's risk status; thus the total number of screens available to the population are distributed according to risk status. Using data from the Edinburgh randomised trial of breast cancer screening these policies have been compared. It is estimated that the proportion of cases detected by screening in the three years following the completion of the initial screening round could be raised from 60% to 67% by adopting a risk strategy. Lead time benefits are also quantified as are the comparisons for an established screening programme.

Risk factors for breast cancer with applications to selection for the prevalence screen.

There have been many studies of individual risk factors for breast cancer; most of the factors concerned may be broadly grouped into demographic and dietary, reproductive history, endocrine related, family history of breast cancer, and previous history of breast disease. Some of these studies have examined the combined effect of these factors. The present case-control study does this in the context of a randomised controlled trial of breast cancer screening. The relative risks that we have obtained are, in general, of similar magnitude to those in other reports. The relevance of the results to a screening programme is discussed.

Comparative pathology of prevalent and incident cancers detected by breast screening. Edinburgh Breast Screening Project.

In the Edinburgh Breast Screening Project 210 cancers were detected from commencement in 1979 up to December, 1984. By this time the full initial cohort had completed at least 3 visits and a proportion had attended for up to 5 visits, so pathological characteristics for prevalent and incident cancers could be compared. The main differences are in distribution of histological type of cancer, detection of occult invasive disease, and lymph-node positivity among incident tumours. Only the first of these was statistically significant. This evaluation shows that cancer detection by screening in Edinburgh conforms with screening theory, in which detection of good prognosis tumours is favoured at the prevalence screens, and faster growing, aggressive tumours are found at the incidence screens. Qualitative histopathology may provide a better measure than standard quantitative judgments of size and lymph node status to compare the varieties of cancer detected by screening programmes and to understand the biology of the disease.

Speech quality evaluation using "phoneme-specific" sentences.

A new approach is described for the design of speech materials used in subjective speech quality evaluation. Speech sounds are classified by their acoustic properties, and sentences are composed so as to concentrate all sounds with similar properties within one sentence. As a test of the method, subjective quality data were collected, using both a rank ordering and a rating task, from a set of 12 linear predictive vocoders, whose parameters were chosen so as to equate their bit rates at 2600 bps. The results show that the method can reliably reveal small differences in quality, and also yields information that can be of diagnostic help in determining the causes of quality degradation by a particular vocoder. A set of phoneme-specific sentences is appended.

The Edinburgh randomised trial of screening for breast cancer: description of method.

Edinburgh was selected as one of the centres in the UK Seven-year Trial of Breast Screening of women aged 45-65 which began in 1979. Subsequently, our study was extended to a randomised trial with its own control population within the city. Half the practices were randomly allocated for screening, giving a cluster sampling of women. The total number in the trial is 65,000. Women with previously diagnosed breast cancer are excluded. Women allocated for screening are invited to the clinic and screened according to the procedures specified in the U.K. protocol, having clinical examination every year and mammography on alternate years. The two modalities of screening are assessed independently and the role of nurses is being evaluated. Breast cancer incidence is monitored by pathology register and the local cancer registry office and deaths from the General Register office. Long-term follow-up will be obtained through flagging at NHS Central Register. To determine the value of screening, standard statistical methods will be used to compare breast cancer mortality rates in the whole of the screening population with that of the controls. This trial has a power of 83% of detecting a reduction in mortality of 35% after 7 years of follow-up and a power of 95% of detecting a similar reduction at 10 years (alpha = 0.05, one-sided test).

Is periodicity detection central?

What periodicity is perceived when two different segments of noise, E and F, are alternated dichotically between the ears (Left: EFEFE..; Right FEFEF..)? Earlier work has suggested that for nonfusible signals, preliminary auditory processing is performed separately for the two ears before the results are combined. If so, the perceived period should correspond to the combined lengths of the two segments, since this is the signal that iterates in one ear EF. But if periodicity is detected centrally, the perceived period should be equal to the length of one of the alternated segments (E, F), since each segment presented to one ear is immediately repeated in the other. Subjects compared an alternated sequence with two dichotic iterated sequences. (Left: CCC...; Right: DDD...) in an AXB paradigm, and segment duration was varied between 25 and 400 ms. In one comparison sequence, the iterated segments were equal in duration to the alternated segments (C = D = E = F), and in the other they were twice as long (C = D = E + F). The results show that periodicity is detected separately for the two ears at the shorter durations (nonfusible signals), but becomes central when the segments become long enough for structure to be heard within each segment (i.e, longer than 140-200 ms).

Better spectrograms from children's speech. A research note.

A major problem in the spectrographic analysis of children's speech is the poor resolution of formants, which is the result of the widely spaced harmonics of the high fundamental frequency. An attempt has been made to bypass this problem by exciting a child's vocal tract with an artificial larynx, using a fundamental frequency appropriate to a man. This method has promise for tracking formants in children's speech.