Evidence for a Time Constant in Rate of Speech under Delayed Auditory Feedback

This experiment investigates an apparent discrepancy in experimental measurements of the effect of texture predictability upon reading disruption under delayed auditory feedback (DAF). By measuring relative DAF decrement in three different ways, it is shown that the previous findings can be related; Fillenbaum's hypothesis of increased disruption by DAF with an increase in predictability of the material is rejected, less disruption being obtained after practice on a particular passage. Almost identical ratios of DAF rate divided by normal rate are found irrespective of the type of reading material and stage in practice. This has not been reported previously and suggests that behaviour under DAF may be related to behaviour under normal conditions by a multiplicative constant. These results are also consistent with the notion of limited channel capacity and the partitioning of attention between two sources of information.

Apoptotic cells protect mice from autoimmune inflammation by the induction of regulatory B cells

The maintenance of immune tolerance to apoptotic cells (AC) within an inflammatory milieu is vital to prevent autoimmunity. To investigate this, we administered syngeneic AC i.v. into mice carrying a cohort of ovalbumin (OVA)-specific transgenic T cells (DO11.10) along with OVA peptide and complete Freund's adjuvant, observing a dramatic increase in OVA-specific IL-10 secretion. Activated splenic B cells responded directly to AC, increasing secretion of IL-10, and this programming by AC was key to inducing T cell-derived IL-10. We went on to ask whether AC are able to modulate the course of autoimmune-mediated, chronic inflammation. AC given up to 1 month before the clinical onset of collagen-induced arthritis protected mice from severe joint inflammation and bone destruction. Antigen-specific CD4(+) T cells again secreted significantly more IL-10, associated with a reduced titer of pathogenic anti-collagen II antibodies. Inhibition of IL-10 in vivo reversed the beneficial effects of AC. Passive transfer of B cells from AC-treated mice provided significant protection from arthritis. These data demonstrate that AC exert a profound influence on an adaptive immune response through the generation of CD19(+) regulatory B cells, which in turn are able to influence the cytokine profile of antigen-specific effector T cells.

A tissue engineering approach to meniscus regeneration in a sheep model

OBJECTIVE

Regeneration of the meniscal tissue occurs to a limited extent, and the loss of meniscal tissue leads to osteoarthritis. A new biomaterial consisting of hyaluronic acid and polycaprolactone was used as a meniscus substitute in sheep to evaluate the properties of the implant material with regard to size, biomechanical stability, tissue ingrowth, and integration.

METHODS

Eight sheep (right stifle joints) were treated with three total and three partial meniscus replacements while two meniscectomies served as empty controls. The animals were euthanized after 6 weeks. The specimens were assessed by gross inspection and histology, and compared with the nonoperated left joints.

RESULTS

The surgical technique was found to be feasible. The implants remained in position, did not tear, and showed excellent tissue ingrowth to the capsule. Tissue integration was also observed between the original meniscus and the implant. However, graft compression and extrusion occurred. The histological investigation revealed tissue formation, cellular infiltration and vascularization. Cartilage degeneration was more severe in the operated joints.

CONCLUSION

The present study shows promising results concerning the qualities of this biomaterial with regard to implantation technique, stability and tissue ingrowth.

The early response to major trauma and intramedullary nailing

The stress response to trauma is the summation of the physiological response to the injury (the 'first hit') and by the response to any on-going physiological disturbance or subsequent trauma surgery (the 'second hit'). Our animal model was developed in order to allow the study of each of these components of the stress response to major trauma. High-energy, comminuted fracture of the long bones and severe soft-tissue injuries in this model resulted in a significant tropotropic (depressor) cardiovascular response, transcardiac embolism of medullary contents and activation of the coagulation system. Subsequent stabilisation of the fractures using intramedullary nails did not significantly exacerbate any of these responses.

Osteoarthritis cartilage histopathology: grading and staging

OBJECTIVE

Current osteoarthritis (OA) histopathology assessment methods have difficulties in their utility for early disease, as well as their reproducibility and validity. Our objective was to devise a more useful method to assess OA histopathology that would have wide application for clinical and experimental OA assessment and would become recognized as the standard method.

DESIGN

An OARSI Working Group deliberated on principles, standards and features for an OA cartilage pathology assessment system. Using current knowledge of the pathophysiology of OA morphologic features, a proposed system was presented at OARSI 2000. Subsequently, this was widely circulated for comments amongst experts in OA pathology.

RESULTS

An OA cartilage pathology assessment system based on six grades, which reflect depth of the lesion and four stages reflecting extent of OA over the joint surface was developed.

CONCLUSIONS

The OARSI cartilage OA histopathology grading system appears consistent and simple to apply. Further studies are required to confirm the system's utility.

Expression of parathyroid hormone-related protein and its receptor in bone metastases from prostate cancer

Studies of breast cancer suggest that parathyroid hormone-related protein (PTHrP) is important in the development of bone metastases. To determine whether PTHrP expression is important in prostate cancer metastasis, immunohistochemistry and in situ hybridization were used to assess the expression of PTHrP and its receptor in primary prostate cancer and bone metastases from both prostate and non-prostate cancers. PTHrP was expressed in more prostate primary tumours than bone metastases (p=0.003, Fisher's exact test). All bone metastases from non-prostate cancers expressed PTHrP. In contrast, PTHrP receptor was expressed in all bone metastases, but in only 19% of primary prostate tumours (p=0.001). The receptor to PTHrP was found to be highly expressed in bone metastases from prostate and other primaries, whereas PTHrP protein was found to have lower expression in the bone metastases than in the primary tumours. In conclusion, the expression of the receptor to PTHrP is increased in bone metastases from prostate cancer and may play an important role in their formation.

Extracellular matrix proteins protect small cell lung cancer cells against apoptosis: a mechanism for small cell lung cancer growth and drug resistance in vivo

Resistance to chemotherapy is a principal problem in the treatment of small cell lung cancer (SCLC). We show here that SCLC is surrounded by an extensive stroma of extracellular matrix (ECM) at both primary and metastatic sites. Adhesion of SCLC cells to ECM enhances tumorigenicity and confers resistance to chemotherapeutic agents as a result of beta1 integrin-stimulated tyrosine kinase activation suppressing chemotherapy-induced apoptosis. SCLC may create a specialized microenvironment, and the survival of cells bound to ECM could explain the partial responses and local recurrence of SCLC often seen clinically after chemotherapy. Strategies based on blocking beta1 integrin-mediated survival signals may represent a new therapeutic approach to improve the response to chemotherapy in SCLC.

Evaluation of Japanese quail as a model system for avian transgenesis using avian leukosis viruses

Vertical transmission of avian leukosis viruses (ALV) can occur genetically through the germline for both male and female chickens but only nongenetically or congenitally through the female. We had previously shown that tolerantly ALV-infected males, from ALV injection into fertile chicken eggs at day of set, can transmit proviral DNA to their progeny through the germline. An attempt was made to repeat this successful retroviral germline insertion technique of chickens in Japanese quail. After an initial difficulty of infecting quail chicks in ovo at day of set with high titer nonpathogenic recombinant and pathogenic ALV, adequate numbers of tolerantly ALV-infected quail were produced by injecting ALV-infected chicken embryo fibroblasts (CEF) at day of set. Tolerantly ALV-infected male and female quail were then mated to nonviremic quail and vertical transmission of ALV to progeny chicks was determined by analyzing blood for viral antigens and proviral DNA using standard techniques. Vertical transmission of ALV was only detected in the progeny of viremic females. Thus, little or no germline transmission of ALV to progeny occurred from viremic males. Tolerantly ALV-infected males and females from congenital ALV infection, which should infect the embryo and presumably the primordial germ cells (PGC) earlier than egg injection, were mated to nonviremic quails. Vertical transmission of ALV to progeny chicks was analyzed as before. Again, vertical transmission of ALV was only detected in the progeny of viremic females. We conclude that Japanese quail will not be useful in avian transgenic studies involving ALV retroviral vectors.

Avian leukemias and lymphomas: interplay between retroviruses and herpesviruses

Avian leukemias and lymphomas are caused primarily by retroviruses and herpesviruses. The protooncogenes activated by avian retroviral insertions in B & T-cell lymphomas will be summarized, with discussion on a new common insertion site, bravo, associated with RAV-O LTR insertion. Two novel interactions between avian retroviruses and Marek's disease herpesvirus (MDV) will be described: one involves direct interactions between putative viral oncoproteins and the other integrative recombination between these two viruses.

Dobutamine stress echocardiography predicts cardiac events in heart transplant patients

BACKGROUND

Cardiac transplantation is an accepted treatment modality for end-stage heart failure. Coronary artery disease remains a major cause of mortality in the long term after heart transplantation. Despite the high prevalence of coronary artery disease in heart transplant recipients, currently used noninvasive tests as well as invasive tests are highly unreliable in predicting prognosis. We sought to test the hypothesis that the abnormalities induced by dobutamine stress echocardiography (DSE) may be of prognostic value in predicting acute cardiac events and mortality in heart transplant patients.

METHODS AND RESULTS

We prospectively studied 86 survivors of orthotopic heart transplantation and followed them for a mean period of 2 years after the DSE. The patients' median age was 51 +/- 10 years, and mean duration since transplant was 57.7 +/- 29 months (range, 3 to 120 months, mean +/- SD). DSE was performed by a standard protocol (dobutamine 5, 10, 20, 30, and 40 micrograms.kg-1.min-1 at 5-minute stages). DSE was defined as positive for development of new or worsening regional wall motion abnormality or failure of augmentation. Nine patients were excluded from analysis (5 because of acute allograft rejection and 4 because of poor acoustic window). Thus, data from 77 patients were analyzed. Fifty-seven of 77 (74%) had positive DSE. After 24 months of follow-up, 19 of 57 patients with abnormal DSE (33%) experienced 22 major cardiac events. In contrast, no event occurred in patients with normal DSE. Of the 19 with cardiac events, there were 7 episodes of heart failure (including 3 deaths), 4 had unstable angina, and 5 died of cardiac causes. Three patients had myocardial infarction, and 3 others died of noncardiac causes. Among the variables examined, the baseline left ventricular ejection fraction was lower (44 +/- 3.8 versus 51 +/- 1.4) and peak wall motion score index was higher (2.01 +/- 0.4 versus 1.44 +/- 0.4) in the patients group with cardiac events than in those without events.

CONCLUSIONS

These results suggest that DSE has significant value in predicting prognosis in post-heart transplant patients. Further studies are needed to define the role of DSE as a routine test for predicting prognosis in cardiac transplant recipients.

Noninvasive detection of transplant coronary artery disease by dobutamine stress echocardiography

Coronary artery disease has emerged as the leading cause of late morbidity and mortality in heart transplant recipients. The incidence of allograft coronary artery disease has been reported to be as high as 40% to 50% by 5 years. Coronary angiography remains the standard approach for surveillance of coronary artery disease in this patient population. However, the detection and surveillance of allograft coronary disease by noninvasive methods remains a challenge. The purpose of this study was to determine the value of dobutamine stress echocardiography as a noninvasive screening test to rule out the presence of anatomically significant allograft coronary artery disease and to assess its prognostic power. Dobutamine stress echocardiography was carried out according to a standard protocol in which dobutamine was infused at 5, 10, 20, 30, and 40 micrograms/kg/min intravenously at 5-minute stages with 12-lead electrocardiogram and blood pressure monitoring. Left ventricular wall motion was analyzed at baseline and at peak dobutamine dose. Mean age (+/- standard error of the mean) of the study population was 50.5 +/- 1.5 years, and mean duration (+/- standard error of the mean) since transplantation was 57 +/- 5 months. The sensitivity, specificity, and positive and negative predictive accuracy of dobutamine stress echocardiography were 95%, 55%, 69%, and 92%, respectively. In the 12-month follow-up study 12 patients with abnormal dobutamine stress echocardiographic findings had 15 major cardiac events whereas no event occurred in patients with normal dobutamine stress echocardiograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrioventricular fistula: an unusual complication of endomyocardial biopsy in a heart transplant recipient

Endomyocardial biopsy remains the primary method for diagnosis of cardiac allograft rejection. Generally, endomyocardial biopsy is considered a relatively safe procedure in heart transplant recipients. Complications that have been reported are related to catheter insertion and include carotid arterial puncture, prolonged bleeding, vasovagal reaction, ventricular tachyarrhythmias, and transient conduction abnormalities. Serious complications such as right ventricular perforation with cardiac tamponade may also occur. Most complications are usually without significant long-term sequelae. This report describes an unusual case of atrioventricular fistula between the right atrium and left ventricle that occurred during a routine endomyocardial biopsy in a heart transplant recipient. Sudden hemodynamic compromise developed in this patient soon after heart biopsy associated with hemodynamic picture of high-output heart failure. Right heart catheterization, including oximetry, peripheral venous contrast echocardiography, color flow Doppler studies, and transesophageal echocardiography confirmed the diagnosis of fistulous communication between the right atrium and left ventricle, most likely through the membranous interventricular septum. Conservative medical management resulted in striking clinical improvement within 48 hours commensurate with spontaneous closure of the right atrium-to-left ventricle fistula documented by hemodynamic and echocardiographic studies.

The expression of mouse tyrosinase in chick cells in vitro and in vivo when controlled by a constitutive promoter

Virally introduced mouse tyrosinase expression was checked both in vitro and in vivo in chicken cells and tissues. The results indicate that a constitutive promoter is able to express mouse tyrosinase in a variety of cells and tissues both in vitro and in vivo. Tyrosinase expression is marked by pigment production in situ, which is visible at macroscopic as well as microscopic levels without the use of substrates. It is concluded that tyrosinase can be a valuable marker for tracking gene insertion since it is spontaneously expressed. The expression of tyrosinase in some cells and tissues has a detrimental effect, however, and should be controlled by tissue-specific promoters.

Suicidal intent, hopelessness and depression in a parasuicide population: the influence of social desirability and elapsed time

This paper reports the first British study to assess the construct validity of Beck's Hopelessness Scale (HS) and the Beck Depression Inventory (BDI). On the basis of interviews with 50 economically active parasuicide patients, it was confirmed that hopelessness accounts for the relationship between depression and suicidal intent. Moreover, it was shown that social desirability neither confounds the relationship between hopelessness and suicidal intent, nor has any predictive power in explaining variation in suicidal intent. On the other hand, the interval ('elapsed time') between the commencement of the parasuicidal act and of the research interview was significantly and positively correlated with suicidal intent, and elapsed time was a significant predictor of the total score on Beck's Suicidal Intent Scale. Two explanations for this finding are proposed: the first is based on the possibility that elapsed time is an indirect or proxy measure of medical seriousness; the second derives from the likely impact of prolonged hospital stay on the patient's interpretation or understanding of his/her behaviour. Researchers are advised to take into account the moderating effect of elapsed time when designing studies which examine psychological processes in parasuicide.

Five-year reliability of self-reported alcohol consumption

Reliability of alcohol consumption reported on a self-administered questionnaire was examined in 73 gynecologic outpatients. The questionnaire included quantity-frequency questions on current beverage-specific alcohol use (wine, beer and liquor). The questions were replicated 5 years later for both the earlier period and for current drinking patterns. Results indicated that, in general, original and retrospective data were highly correlated. Only recall of wine, the least frequently drunk beverage, was more highly correlated with current than with original consumption. Frequency of drinking was typically recalled better than quantity per occasion. Beverage-specific absolute alcohol per day (AA) was less reliable than total AA. Retrospective AA values accounted for 86% of the variability in original scores. The heaviest drinkers, however, tended to report disproportionately greater alcohol intake in retrospect. Thus, almost twice as many heavy drinkers were identified on the basis of their retrospective reports compared to those identified by their original reports. Results from this study suggest that considerable confidence can be placed in retrospective reports of total alcohol consumption by nonalcoholic women over a relatively long-term interval and that heavy drinking may be reported more accurately retrospectively than currently.

Nasal histamine and heparin in chronic rhinitis

Histamine and heparin, both free and cellular, were assayed in the nasal mucosa of 11 atopic and 15 nonatopic patients undergoing turbinectomy for chronic rhinitis. There was no significant difference between the free and cellular histamine levels of the atopic and nonatopic patients. There was also no significant difference between the free heparin levels of atopic and nonatopic patients. Mean cellular heparin was, however, significantly greater in the nonatopic group. This finding, together with the results of mast cell counting, suggests either that in atopic patients heparin stores are already depleted prior to turbinectomy, or that in nonatopic individuals nasal mast cells contain an excess of heparin in nonreleasable stores.

Flexible medullary nailing of tibial shaft fractures

Fifty-two tibial shaft fractures in 50 patients were treated with flexible medullary nails (Ender type). In 32 cases the fracture was closed and in the remaining 28 cases the fracture was open. Forty-eight of the 52 fractures united in an average time of 16.8 weeks and there were no cases of deep infection or osteomyelitis. Nonunion in four patients required a secondary procedure to obtain union. Flexible medullary nailing is an excellent method for fixation of tibial shaft fractures because it combines the benefits of closed nailing and functional bracing while minimizing the disadvantages of each. Three-point fixation within the medullary canal maintains length alignment and avoids rotational problems. Nailing is done by closed methods without reaming. The technique allows early weight-bearing in a patellar tendon bearing cast or functional brace. Dynamic controlled motion at the fracture site leads to early callus formation which is biomechanically and biologically favorable. The procedure is relatively easy to perform, short in duration, and requires little specialized equipment. Flexible medullary nailing is an alternative treatment modality for selected open and closed displaced tibial shaft fractures.

Humoral immune response to herpes simplex virus type 2 glycoproteins in patients receiving a glycoprotein subunit vaccine

Serial serum specimens from 22 herpes simplex virus (HSV)-seronegative recipients of an HSV type 2 (HSV-2) glycoprotein subunit vaccine were analyzed by radioimmunoprecipitation and polyacrylamide gel electrophoresis for the development of antibodies to HSV-2 gB, gD, and g80, a complex of gC and gE. Volunteers received 50 (n = 12) or 100 micrograms (n = 10) of vaccine at days 0, 28, and 140; sera were drawn weekly for 8 weeks and again at days 140, 147, and 365. Among seronegative volunteers, antibody to gB was detected 2 weeks after the first dose, while antibodies to g80 and gD were detected after the second dose (day 35). Antibodies to nonglycosylated HSV-specific proteins were not detected. A dose-response effect between recipients of 50- and 100-micrograms doses was observed in the proportion of vaccine recipients seroconverting to g80 and in the proportion of recipients retaining antibodies to both gD and g80 over time. Diminishing complement-independent neutralizing antibody titers occurred after the second dose and were associated with loss or reduction of detectable antibody to gD. Volunteers who were seropositive for HSV-1-specific antibody (n = 11) were also enrolled in the trial and received 50-micrograms doses of vaccine. Vaccination resulted in conversion to HSV-2 complement-independent neutralizing antibody specificity or indeterminant specificity in 10 of 11 volunteers. These shifts were accompanied by changes in the radioimmunoprecipitation and polyacrylamide gel electrophoresis profile. These changes, which were apparent by 14 days after the first vaccine dose, included de novo appearance or increased levels of antibody to g80 and increased levels of antibody to gD and gB. These studies document the immunogenicity of solubilized glycoproteins gB, gD, gC, and, possibly, gE in humans.

Herpes simplex virus type-2 glycoprotein-subunit vaccine: tolerance and humoral and cellular responses in humans

Twenty-three subjects were administered three doses of inactivated herpes simplex virus (HSV) type 2 (HSV-2) glycoprotein-subunit vaccine, with doses 2 and 3 being given four and 22 weeks after dose 1. Both HSV-neutralizing antibody and antibody effective in antibody-dependent cell-mediated cytotoxicity were detected in serum samples of 12 of the 13 initially seronegative subjects by week 8. The geometric mean titers of both antibody types decreased between weeks 8 and 22 but increased one week after dose 3. HSV-neutralizing antibody remained detectable in serum samples of seven of the 10 initially seronegative subjects assayed seven months after dose 3. Cell-mediated immunity was detected by lymphocyte transformation responses to HSV-2 after vaccine administration in 12 of the 13 initially seronegative subjects. Unlike humoral antibody, which waned over time, in vitro cell-mediated immune responses remained stable over the seven-month follow-up period after dose 3. This HSV-2-subunit vaccine is well tolerated and elicits both humoral and cell-mediated immune responses to HSV.

Private medical insurance in New Zealand: issues of membership and growth

Questions concerning ownership of private medical insurance were included in a recent Department of Statistics' survey of a random sample of almost 7000 New Zealanders. The results indicated that 35% of those surveyed owned private medical insurance and such ownership was significantly related to various social, demographic and health related variables. The findings are discussed in terms of the possibilities for growth of private medical insurance and the implications of such growth for both the public and the private health care sectors.

Necrotizing pancreatitis in renal transplant patients

Acute necrotizing pancreatitis developed in 5 of 405 patients who underwent renal transplantation. All five patients were taking immunosuppressive medication (azathioprine and steroids). Three patients also received rabbit antithymus serum. Alcohol ingestion or cholelithiasis did not play any causative role in the pancreatitis, which began between 7 days and 13 months after renal transplantation. The delay from the time of admission for pancreatitis to surgical exploration was a mean of 17 days. Operative findings included pancreatic necrosis, hemorrhage and abscess formation. All five patients died of the complications of necrotizing pancreatitis--persistent sepsis, respiratory and renal failure, upper gastrointestinal bleeding and disseminated intravascular coagulation. This review demonstrates that prolonged conservative therapy in renal transplant patients with necrotizing pancreatitis is associated with high mortality. The authors believe that earlier surgical intervention will lead to increased survival.

Shadowing at one and at two ears

The assumption that speech shadowing commandeers all the subject's capacity was tested in two ways: by manipulating the linguistic parameters of the non-attended message, and by superimposing a task of repeating the second message whenever possible while shadowing the first message. Eight subjects shadowed prose or random words (130 words per min). Non-attended messages of either type were also presented as forward, or reversed speech. With reversed speech, percentage shadowing scores for random words were less than prose (P < 0.001). Random word shadowing was further adversely affected with non-attended, forward speech, there being a significant interaction (P < 0.001) between shadowed message type and intelligibility of the non-attended message. Subjects repeated more words shadowing both messages than one alone (P < 0.001), despite the switching which this entailed, and shadowing scores were related to the redundancy of both message combinations.

Two studies on the process of negative modification

The properties of words with negative affix are investigated in two studies. The first analyzed a subset of qualifier adjectives elicited from three age groups. A significant age differential was found for the proportion of words with negative prefix to the number of negatively evaluated words generated; this could not be simply explained by the "Pollyanna hypothesis." In a second study, alternative words of similar meaning were elicited for 80 words: 20 personality-descriptive adjectives, two versions of their negative modification, and antonyms for the 20 words. A measure of informational uncertainty was calculated for each of the four word types across subjects. Significant effects for words with a negative affix result, which are distinct from that obtained with negatively evaluated antonyms. Comment on these findings makes reference to linguistic work on negation while pointing out that, in the context of other experimental studies, this behavior may be subsumed under a more general cognitive process. The observations open up to experimental investigation the subject of the negative prefix and the generative process which probably underlies it.