Inactivation of the N-CAM gene in mice results in size reduction of the olfactory bulb and deficits in spatial learning

Neural-cell adhesion molecules (N-CAMs) are members of the immunoglobulin superfamily mediating homo- and heterophilic cell-cell interactions. N-CAM exists in various isoforms which are generated by alternative splicing. During embryonic development, N-CAMs are expressed in derivatives of all three germ layers, whereas in the adult animal they are predominantly present in neural tissue. Processes like neurulation, axonal outgrowth, histogenesis of the retina and development of the olfactory system are correlated with the regulated expression of N-CAMs. We show here that N-CAM-deficient mice generated by gene targeting appear healthy and fertile, but adult mutants show a 10% reduction in overall brain weight and a 36% decline in size of the olfactory bulb. N-CAM deficiency coincides with almost total loss of protein-bound alpha-(2,8)-linked polysialic acid, a carbohydrate structure thought to be correlated with neural development and plasticity. The animals showed deficits in spatial learning when tested in the Morris water maze, whereas activity and motor abilities appeared normal.

11beta-hydroxysteroid dehydrogenase type 1 knockout mice show attenuated glucocorticoid-inducible responses and resist hyperglycemia on obesity or stress

Glucocorticoid hormones, acting via nuclear receptors, regulate many metabolic processes, including hepatic gluconeogenesis. It recently has been recognized that intracellular glucocorticoid concentrations are determined not only by plasma hormone levels, but also by intracellular 11beta-hydroxysteroid dehydrogenases (11beta-HSDs), which interconvert active corticosterone (cortisol in humans) and inert 11-dehydrocorticosterone (cortisone in humans). 11beta-HSD type 2, a dehydrogenase, thus excludes glucocorticoids from otherwise nonselective mineralocorticoid receptors in the kidney. Recent data suggest the type 1 isozyme (11beta-HSD-1) may function as an 11beta-reductase, regenerating active glucocorticoids from circulating inert 11-keto forms in specific tissues, notably the liver. To examine the importance of this enzyme isoform in vivo, mice were produced with targeted disruption of the 11beta-HSD-1 gene. These mice were unable to convert inert 11-dehydrocorticosterone to corticosterone in vivo. Despite compensatory adrenal hyperplasia and increased adrenal secretion of corticosterone, on starvation homozygous mutants had attenuated activation of the key hepatic gluconeogenic enzymes glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, presumably, because of relative intrahepatic glucocorticoid deficiency. The 11beta-HSD-1 -/- mice were found to resist hyperglycamia provoked by obesity or stress. Attenuation of hepatic 11beta-HSD-1 may provide a novel approach to the regulation of gluconeogenesis.

Insulin-regulatable tissues express a unique insulin-sensitive glucose transport protein

At least three different glucose transport systems exist in mammalian cells. These are: (1) the constitutively active, facilitative carrier characteristic of human erythrocytes, Hep G2 (ref. 2) cells and rat brain; (2) the Na-dependent active transporter of kidney and small intestine; and (3) the facilitative carrier of rat liver (B. Thorens and H. F. Lodish, personal communication). A fourth possible glucose transport system is the insulin-dependent carrier that may be specific to muscle and adipose tissue. This transporter resides primarily in an intracellular compartment in resting cells from where it translocates to the cell surface upon cellular insulin exposure. This raises the question of whether hormonal regulation of glucose transport is conferred by virtue of a tissue-specific signalling mechanism or a tissue-specific glucose transporter. Here we present data supporting the latter concept based upon a monoclonal antibody against the fat cell glucose transporter that identifies a unique, insulin-regulatable glucose transport protein in muscle and adipose tissue.

A prospective assessment of mortality in chronic spinal cord injury

STUDY DESIGN

Prospective mortality study.

OBJECTIVE

To assess the relationship between comorbid medical conditions and other health-related factors to mortality in chronic spinal cord injury (SCI).

SETTING

Boston, MA, USA.

METHODS

Between 1994 and 2000, 361 males >/=1 year after injury completed a respiratory health questionnaire and underwent pulmonary function testing. Cause-specific mortality was assessed over a median of 55.6 months (range 0.33-74.4 months) through 12/31/2000 using the National Death Index.

RESULTS

At entry, mean (+/-SD) age was 50.6+/-15.0 years (range 23-87) and years since injury was 17.5+/-12.8 years (range 1.0-56.5). Mortality was elevated (observed/expected deaths=37/25.1; SMR=1.47; 95% CI=1.04-2.03) compared to US rates. Risk factors for death were diabetes (RR=2.62; 95% CI=1.19-5.77), heart disease (RR=3.66; 95% CI=1.77-7.78), reduced pulmonary function, and smoking. The most common underlying and contributing causes of death were diseases of the circulatory system (ICD-9 390-459) in 40%, and of the respiratory system in 24% (ICD-9 460-519).

CONCLUSIONS

These results suggest that much of the excess mortality in chronic SCI is related to potentially treatable factors. Recognition and treatment of cardiovascular disease, diabetes, and lung disease, together with smoking cessation may substantially reduce mortality in chronic SCI.

Postmortem evidence of structural brain changes in schizophrenia. Differences in brain weight, temporal horn area, and parahippocampal gyrus compared with affective disorder

The brains of 232 patients with a case-note diagnosis of schizophrenia or affective disorder who died in one mental hospital over a period of 22 years were weighed, and were assessed in a coronal section at the level of the interventricular foramina. From this sample were eliminated the brains of patients whose illnesses did not meet the Washington University criteria for a diagnosis of definite schizophrenia or primary affective disorder and those brains that showed significant histopathologic evidence of Alzheimer's-type change or cerebrovascular disease. This left a sample of 41 patients with schizophrenia and 29 patients with affective disorder. With age, sex, and year of birth controlled for, the brains of the patients with schizophrenia were 6% lighter, had lateral ventricles that were larger in the anterior (by 19%), and particularly in the temporal, (by 97%) horn cross section, and had significantly thinner parahippocampal cortices (by 11%). The findings provide postmortem confirmation of reports of ventricular enlargement in radiological studies and suggest that such enlargement is associated with tissue loss in the temporal lobe. The changes in schizophrenia were of a lesser degree than those seen in a sample of brains of patients with Alzheimer's-type dementia and Huntington's chorea.

Schizophrenia as an anomaly of development of cerebral asymmetry. A postmortem study and a proposal concerning the genetic basis of the disease

Schizophrenia is associated with structural changes (eg, a mild degree of ventricular enlargement) in the brain, although whether these precede onset of illness or progress with episodes is not established. In a postmortem study, we find that ventricular enlargement affects the posterior and particularly the temporal horn of the lateral cerebral ventricle. By comparison with controls and with patients suffering from Alzheimer-type dementia (in which there is also temporal horn enlargement), the change is highly significantly selective to the left hemisphere. This deviation was not accompanied by an increase in glial cell number (examined chemically by assay of diazepam-binding inhibitor immunoreactivity and microscopically by density of staining with the Holzer technique). The findings are consistent with the view that schizophrenia is a disorder of the genetic mechanisms that control the development of cerebral asymmetry.

Hand-held thoracic sonography for detecting post-traumatic pneumothoraces: the Extended Focused Assessment with Sonography for Trauma (EFAST)

BACKGROUND

Thoracic ultrasound (EFAST) has shown promise in inferring the presence of post-traumatic pneumothoraces (PTXs) and may have a particular value in identifying occult pneumothoraces (OPTXs) missed by the AP supine chest radiograph (CXR). However, the diagnostic utility of hand-held US has not been previously evaluated in this role.

METHODS

Thoracic US examinations were performed during the initial resuscitation of injured patients at a provincial trauma referral center. A high frequency linear transducer and a 2.4 kg US attached to a video-recorder were used. Real-time EFAST examinations for PTXs were blindly compared with the subsequent results of CXRs, a composite standard (CXR, chest and abdominal CT scans, clinical course, and invasive interventions), and a CT gold standard (CT only). Charts were reviewed for in-hospital outcomes and follow-up.

RESULTS

There were 225 eligible patients (207 blunt, 18 penetrating); 17 were excluded from the US examination because of battery failure or a lost probe. Sixty-five (65) PTXs were detected in 52 patients (22% of patients), 41 (63%) being occult to CXR in 33 patients (14.2% whole population, 24.6% of those with a CT). The US and CXR agreed in 186 (89.4%) of patients, EFAST was better in 16 (7.7%), and CXR better in 6 (2.9%). Compared with the composite standard, the sensitivity of EFAST was 58.9% with a likelihood ratio of a positive test (LR+) of 69.7 and a specificity of 99.1%. Comparing EFAST directly to CXR, by looking at each of 266 lung fields with the benefit of the CT gold standard, the EFAST showed higher sensitivity over CXR (48.8% versus 20.9%). Both exams had a very high specificity (99.6% and 98.7%), and very predictive LR+ (46.7 and 36.3).

CONCLUSION

EFAST has comparable specificity to CXR but is more sensitive for the detection of OPTXs after trauma. Positive EFAST findings should be addressed either clinically or with CT depending on hemodynamic stability. CT should be used if detection of all PTXs is desired.

Cloning of a bcl-2 homologue by interaction with adenovirus E1B 19K

A number of DNA viruses carry apoptosis-inhibiting genes which enable the virus to escape from the host response. The adenovirus E1B 19K protein can inhibit apoptosis induced by E1A, tumour-necrosis factor-alpha, FAS antigen and nerve growth factor deprivation. The molecular basis of this inhibition remains poorly understood, but the fact that protection is seen in the absence of other viral proteins suggests that E1B 19K targets cellular proteins. We report here the identification of three cellular proteins that bind E1B 19K. One of these is a new member of the bcl-2 family, which we have called bak (for bcl-2 homologous antagonist/killer). This protein, which is expressed in a wide variety of cell types, binds to E1B 19K and to the Bcl-2 homologue Bcl-XL (ref. 17) in yeast. In addition, overexpression of bak in sympathetic neurons deprived of nerve growth factor accelerates apoptosis and blocks the protective effect of co-injected E1B 19K.

Influence of parameters on the heterogeneous photocatalytic degradation of pesticides and phenolic contaminants in wastewater: a short review

In recent years, the application of heterogeneous photocatalytic water purification processes has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible-light spectrum. This paper aims to review and summarize the recent works on the titanium dioxide (TiO(2)) photocatalytic oxidation of pesticides and phenolic compounds, predominant in storm and wastewater effluents. The effects of various operating parameters on the photocatalytic degradation of pesticides and phenols are discussed. Results reported here suggest that the photocatalytic degradation of organic compounds depends on the type and composition of the photocatalyst and, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, catalyst application mode, and calcination temperature in the water environment. A substantial amount of research has focused on the enhancement of TiO(2) photocatalysis by modification with metal, non-metal and ion doping. Recent developments in TiO(2) photocatalysis for the degradation of various pesticides and phenols are also highlighted in this review. It is evident from the literature survey that photocatalysis has good potential to remove a variety of organic pollutants. However, there is still a need to determine the practical utility of this technique on a commercial scale.

Carpal tunnel release. A prospective, randomized assessment of open and endoscopic methods

To define the role of two-portal endoscopic carpal-tunnel release as a method for the treatment of compression of the median nerve at the wrist, a prospective, randomized, multicenter study was performed on 169 hands in 145 patients. Either open or endoscopic carpal-tunnel release was performed in all of the patients who had clinical signs and symptoms consistent with carpal tunnel syndrome, had not responded to or had refused non-operative management, and had had electrodiagnostic studies consistent with carpal tunnel syndrome. Follow-up evaluations were performed at twenty-one, forty-two, and eighty-four days. At the end of the follow-up period, both the open and endoscopic methods had resulted in high levels of achievement of the primary outcomes (relief of pain and paresthesias). The numbness and paresthesias were relieved in eighty (98 per cent) of eighty-two hands in the open-release group compared with seventy-seven (99 per cent) of seventy-eight hands in the endoscopic-release group. This parameter was not recorded for three hands in the open-release group or six hands in the endoscopic-release group. The satisfaction of the patients with the procedure, graded on a scale of 0 to 100 per cent, averaged 84 per cent in the open-release group compared with 89 per cent in the group that had had endoscopic release. We found no significant differences between the two groups with regard to the secondary quantitative-outcome measurements, including two-point discrimination, postoperative interstitial-pressure data for the carpal canal, Semmes-Weinstein monofilament testing, and motor strength. The open technique resulted in more tenderness of the scar than did the endoscopic method. Thirty-two (39 per cent) of eighty-two hands in the open-release group and fifty (64 per cent) of seventy-eight hands in the endoscopic-release group were not tender at eighty-four days. This parameter was not recorded for three hands in the open-release group and six hands in the endoscopic-release group. The open method also resulted in a longer interval until the patient could return to work (median, twenty-eight days, compared with fourteen days for the open-release and endoscopic-release groups). Four complications occurred in the endoscopic carpal-tunnel release group: one partial transection of the superficial palmar arch, one digital-nerve contusion, one ulnar-nerve neuropraxia, and one wound hematoma.(ABSTRACT TRUNCATED AT 400 WORDS)

A review of methods for the detection of pathogenic microorganisms

The testing and rapid detection of pathogenic organisms is a crucial protocol in the prevention and identification of crises related to health, safety and wellbeing. Pathogen detection has become one of the most challenging aspects in the food and water industries, because of the rapid spread of waterborne and foodborne diseases in the community and at significant costs. With the prospect of inevitable population growth, and an influx of tourism to certain water bodies testing will become a requirement to control and prevent possible outbreaks of potentially fatal illnesses. The legislation is already particularly rigorous in the food industry, where failure to detect pathogenic materials represents a catastrophic event, particularly for the elderly, very young or immune-compromised population types. In spite of the need and requirement for rapid analytical testing, conventional and standard bacterial detection assays may take up to seven days to yield a result. Given the advent of new technologies, biosensors, chemical knowledge and miniaturisation of instrumentation this timescale is not acceptable. This review presents an opportunity to fill a knowledge gap for an extremely important research area; discussing the main techniques, biology, chemistry, miniaturisation, sensing and the emerging state-of-the-art research and developments for detection of pathogens in food, water, blood and faecal samples.

Cigarette smoking, major depression, and other psychiatric disorders among adolescents

OBJECTIVE

To examine cross-sectionally and prospectively relationships of cigarette smoking with major depressive disorder (MDD), controlling for comorbidity in a community sample of adolescents.

METHOD

A representative sample of 1,709 adolescents (aged 14 through 18 years) was assessed by using semistructured diagnostic interviews on two occasions, approximately 1 year apart. Logistic regression analyses were used to examine cross-sectionally and prospectively the relationships between smoking and each psychiatric disorder, while statistically controlling for the other disorders.

RESULTS

Cross-sectional analyses revealed significant relationships of drug abuse/dependence and disruptive behavior disorders with adolescent smoking, even after the co-occurrence of all other disorders was controlled. Prospectively, smoking was found to increase the risk of developing an episode of MDD and drug abuse/dependence, after adjusting for other disorders. Finally, only lifetime prevalence of MDD remained a significant predictor of smoking onset, after controlling for other disorders. Gender did not moderate any of the relationships between psychopathology and smoking.

CONCLUSIONS

The results suggest important relationships between cigarette smoking and psychiatric disorders among adolescents, particularly with regard to MDD, drug abuse/dependence, and disruptive behavior disorders. These findings have important clinical implications, both for psychiatric care and for smoking prevention and cessation efforts with adolescents.

Trauma care regionalization: a process-outcome evaluation

BACKGROUND

Regionalization of trauma care services in our region was initiated in 1993 with the designation of four tertiary trauma centers. The process continued in 1995 with the implementation of patient triage and transfer protocols. Since 1995, the network of trauma care has been expanded with the designation of 33 secondary, 30 primary, and 32 stabilization trauma centers. In addition, during this period emergency medical personnel have been trained to assess and triage trauma victims within minimal prehospital time. The objective of the present study was to evaluate the impact of trauma care regionalization on the mortality of major trauma patients.

METHODS

This was a prospective study in which patients were entered at the time of injury and were followed to discharge from the acute-care hospital. The patients were identified from the Quebec Trauma Registry, a review of the records of acute-care hospitals that treat trauma, and records of the emergency medical services in the region. The study sample consisted of all patients fulfilling the criteria of a major trauma, defined as death, or Injury Severity Score (ISS) > 12, or Pre-Hospital Index > 3, or two or more injuries with Abbreviated Injury Scale scores > 2, or hospital stay of more than 3 days. Data collection took place between April 1, 1993, and March 31, 1998. During this period, four distinct phases of trauma care regionalization were defined: pre-regionalization (phase 0), initiation (phase I), intermediate (phase II), and advanced (phase III).

RESULTS

A total of 12,208 patients were entered into the study cohort, and they were approximately evenly distributed over the 6 years of the study. During the study period, there was a decline in the mean age of patients from 54 to 46 years, whereas the male/female ratio remained constant at 2:1. There was also an increase in the mean ISS, from 25.5 to 27.5. The proportion of patients injured in motor vehicle collisions increased from less than 45% to more than 50% (p < 0.001). The mortality rate during the phases of regionalization were: phase 0, 52%; phase I, 32%; phase II, 19%; and phase III, 18%. These differences were clinically important and statistically significant (p < 0.0001). Stratified analysis showed a significant decline in mortality among patients with ISS between 12 and 49. The change in mortality for patients with fatal injuries (ISS > or = 50) was not significant. During the study period, the mean prehospital time decreased significantly, from 62 to 44 minutes. The mean time to admission after arrival at the hospital decreased from 151 to 128 minutes (p < 0.001). The latter decrease was primarily attributable to changes at the tertiary centers. The proportion of patients with ISS between 12 and 24 and between 25 and 49 who were treated at tertiary centers increased from 56 to 82% and from 36 to 84%, respectively (p < 0.001). Compared with the secondary and primary centers, throughout the course of the study the mortality rate in the secondary and tertiary centers showed a consistent decline (p < 0.001). In addition, the mortality rate in the tertiary centers remained consistently lower (p < 0.001). The results of multivariate analyses showed that after adjusting for injury severity and patient age, the primary factors contributing to the reduced mortality were treatment at a tertiary center, reduced prehospital time, and direct transport from the scene to tertiary centers.

CONCLUSION

This study produced empirical evidence that the integration of trauma care services into a regionalized system reduces mortality. The results showed that tertiary trauma centers and reduced prehospital times are the essential components of an efficient trauma care system.

Pathologic findings from the National Surgical Adjuvant Breast Project (protocol 6). II. Relation of local breast recurrence to multicentricity

One hundred ten local breast recurrences were observed in 1108 pathologically evaluable patients enrolled in NSABP protocol 6 who were treated by lumpectomy and followed for 5 to 95 months (average, 39 months). Eighty-six percent and 95% of all local breast recurrences were noted within 4 and 5 years, respectively, following lumpectomy. Life table analysis revealed their incidence to be 24% for those not and 6% for those receiving lumpectomy and breast irradiation. One hundred four (95%) of the breast recurrences involved the mammary parenchyma and the remaining 6 (5%) involved the skin and/or nipple only. Eleven (10%) of the former were noninvasive. The most common (86%) presentation of breast recurrence appeared to be a localized mass within or close to the quadrant of the index cancer. In 14% the recurrence not only involved the same quadrant, but was more diffuse within the breast extending to remote areas as well. This type was characterized pathologically by marked intralymphatic extension as well as involvement of the overlying skin and/or nipple after the fashion of so-called inflammatory or occult inflammatory breast cancer. The recurrences noted in the skin and/or nipple only were also pathologically characterized by intralymphatic involvement at these sites in the majority of instances. These two forms of breast recurrences appear to reflect the localized growth of highly aggressive invasive breast cancers. The concordance of histologic types and grades of the index and recurrent cancers implies that such events represent growth of overlooked tumor, a deficiency attendant with lumpectomy due to the extreme multifocal nature (not multicentricity) of some breast cancers and/or inadequacies in evaluating the lines of resection of lumpectomy specimens. Sources of error in regard to this latter are identified and guidelines for the examination of such specimens, as well as the assessment of margins, are presented. The observation that local breast recurrences noted following lumpectomy occurred within or close to the same quadrant as the index cancer, despite the presence of multicentric noninvasive cancers in 10% of the patients treated by total mastectomy, minimizes the biological and clinical significance of multicentric foci of cancer present in some breast cancers. Cancer measuring greater than or equal to 2.0 cm, having high histologic and nuclear grades, or intralymphatic extension, were found to have a statistically significant association with local breast recurrence in all patients following lumpectomy. A converse relationship was noted with tubular and scar cancers of types 1 and 4.(ABSTRACT TRUNCATED AT 400 WORDS)

The glycoprotein encoded by the X-linked chronic granulomatous disease locus is a component of the neutrophil cytochrome b complex

The bacteriocidal capacity of phagocytic cells is impaired in X-linked chronic granulomatous disease (X-CGD), a disorder characterized by the absence of functional plasma-membrane-associated NADPH oxidase. The components of this oxidase system, their correspondence with specific genetic loci, and the primary protein defect in X-CGD remain incompletely defined. We recently reported cloning of the putative X-CGD gene on the basis of DNA linkage. To identify the predicted protein in vivo, antibodies were raised to a synthetic peptide derived from the complementary DNA sequence and to a fusion protein produced in Escherichia coli. In Western blots antisera detect a neutrophil protein of relative molecular mass in 90,000 (90K) that is absent in X-CGD patients. Antisera also react with the larger component of cytochrome b recently purified from neutrophil plasma membranes as a complex of glycosylated 90K and non-glycosylated 22K polypeptides. Based on our identification of the X-CGD protein in vivo, we propose that one of its critical roles is to interact with the 22K species to form a functional cytochrome b complex.

Tensional homeostasis in dermal fibroblasts: mechanical responses to mechanical loading in three-dimensional substrates

Many soft connective tissues are under endogenous tension, and their resident cells generate considerable contractile forces on the extracellular matrix. The present work was aimed to determine quantitatively how fibroblasts, grown within three-dimensional collagen lattices, respond mechanically to precisely defined tensional loads. Forces generated in response to changes in applied load were measured using a tensional culture force monitor. In a number of variant systems, resident cells consistently reacted to modify the endogenous matrix tension in the opposite direction to externally applied loads. That is, increased external loading was followed immediately by a reduction in cell-mediated contraction whilst decreased external loading elicited increased contraction. Responses were cell-mediated and not a result of material properties of the matrices. This is the first detailed characterisation of a tensional homeostatic response in cells. The maintained force, after 8 h in culture, was typically around 40-60 dynes/million cells). Maintenance of an active tensional homeostasis has widespread implications for cells in culture and for whole tissue function.

A death-domain-containing receptor that mediates apoptosis

The cell-killing effects of the cytokines TNF-alpha and FasL are mediated by the distinct cell-surface receptors TNFR1, TNFR2 and Fas (also known as CD95/APO-1), which are all members of a receptor superfamily that is important for regulating cell survival. The cytoplasmic regions of TNFR1 and Fas contain a conserved 'death' domain which is an essential component of the signal pathway that triggers apoptosis and activation of the transcription factor NF-kappaB (refs 5,6). Here we report the isolation of a 54K receptor that is a new member of the TNFR superfamily, using the death domain of TNFR1 in a yeast two-hybrid system. This protein, WSL-1, is most similar to TNFR1 itself, particularly in the death-domain region. The gene wsl-1 is capable of inducing apoptosis when transfected into 3T3 and 293 cells, and can also activate NF-kappaB in 293 cells. Like TNFR1, WSL-1 will homodimerize in yeast. WSL-1 also interacts specifically with the TNFR1-associated molecule TRADD. The tissue distribution is very restricted and significantly different from that of Fas and TNFR1.

Short- and long-term survival and function of unilateral intrastriatal dopaminergic grafts in Parkinson's disease

Six patients with Parkinson's disease were followed for 10 to 72 months after human embryonic mesencephalic tissue from four to seven donors was grafted unilaterally into the putamen (4 patients) or putamen plus caudate (2 patients). After 8 to 12 months, positron emission tomography showed a 68% increase of 6-L-[18F]-fluorodopa uptake in the grafted putamen, no change in the grafted caudate, and minor decreases in nongrafted striatal regions. There was therapeutically valuable improvement in 4 patients, but only modest changes in the other 2, both of whom developed atypical features. Patient 4 was without L-dopa from 32 months and had normal fluorodopa uptake in the grafted putamen at 72 months. Overall, the L-dopa dose was reduced by a mean of 10 and 20%, "off" time was reduced by 34 and 44%, and the "off" phase Unified Parkinson's Disease Rating Scale motor score by 18 and 26%, and the duration of the response to a single L-dopa dose increased by 45 and 58% during the first and second years after surgery, respectively. Rigidity and hypokinesia improved bilaterally, but mainly contralateral to the implant. No consistent changes in dyskinesias were observed. We conclude that transplantation of embryonic mesencephalic tissue leads to highly reproducible survival of dopaminergic neurons, inducing clinically valuable improvements in most recipients.

A role for methylation of the hMLH1 promoter in loss of hMLH1 expression and drug resistance in ovarian cancer

Experimental evidence from several sources has identified a link between mismatch repair deficiency and cytotoxic drug resistance. Selection for cisplatin resistance in the human ovarian cancer cell line A2780, results in loss of expression of the mismatch repair protein hMLH1 in most (90%) of the resultant cisplatin-resistant cell lines. Here we demonstrate that the cisplatin sensitive parental cell line displays methylation of the promoter of only one hMLH1 allele, but that the resistant cell lines all exhibit hyper-methylation of the promoters of both hMLH1 alleles. Full methylation of all sites tested was found to be invariably associated with loss of hMLH1 expression, whereas a partial increase in methylation appears compatible with either loss or maintenance of expression. In addition treatment of two of the resistant cell lines with 5-azacytidine, a known inhibitor of methylation, results in re-expression of hMLH1. Clonogenic assays demonstrate that the 5-azacytidine treated cells show increased sensitivity to cisplatin. Furthermore, 12.5% (3/ 24) of ovarian tumours show hypermethylation of the hMLH1 promoter. Expression of hMLH1 is absent in the tumours that are hypermethylated, while all the unmethylated tumours still express the protein. This analysis suggests that methylation of the hMLH1 promoter may be a common mechanism for loss of hMLH1 expression, and possibly for cisplatin-resistance, in ovarian cancer.

Effect of precise mechanical loading on fibroblast populated collagen lattices: morphological changes

The contraction of a collagen lattice by resident fibroblasts causes strains to be developed within that lattice. These strains can be increased or decreased by altering the aspect ratio (ratio of length/width/thickness) of the fibroblast populated collagen lattice, as the cross-sectional area resisting the strain is changed and by the application of an external load. The fibroblasts align themselves with the direction of the maximum principle strain; in effect, these cells are "hiding" from the perceived strain. The direction of the maximum principle strain can be predetermined by the use of a computational finite element analysis. Using the tensioning-Culture Force Monitor to apply pre-determined loading patterns of known repeatable magnitudes, as calculated by the finite element analysis, we have succeeded in aligning fibroblasts into a deliberate predicted orientation. This study has shown that the resident fibroblast population will respond to changes in strain resulting from the most subtle of mechanical loads. This may be an important mechanism in development and repair of connective tissue.

Direct transport to tertiary trauma centers versus transfer from lower level facilities: impact on mortality and morbidity among patients with major trauma

BACKGROUND

The purpose of the study was to compare the outcome of severely injured patients who were transported directly to a Level I, tertiary trauma center with those who were transferred after being first transported to less specialized hospitals.

METHODS

The data were based on all patients treated at three tertiary trauma centers in Quebec between April 1, 1993, and December 31, 1995. There were 1,608 patients (37%) transferred and 2,756 patients (63%) transported directly.

RESULTS

The mean age of the patients was approximately 45 years, and more than 60% were males. The predominant mechanisms of injury were falls and motor vehicle crashes. The transfer and direct transport groups were similar with respect to age, gender, and mechanism of injury. Body regions injured were also similar with the exception of head or neck injuries (transfer, 56%; direct, 28%; p < 0.0001). The mean Injury Severity Score was 14, the mean Pre-Hospital Index score was 5.5, and the mean Revised Trauma Score was 7.5. The two groups were similar with respect to these injury severity measures. The primary outcome of interest was mortality described as overall death rate, death rate in the emergency room, and death rate after admission. Other outcomes studied were hospital length of stay and duration of treatment in an intensive care unit. When compared with the direct transport group, transferred patients were at increased risk for overall mortality (transfer, 8.9%; direct, 4.8%; odds ratio, 1.96; 95% confidence interval (CI) = 1.53-2.50), emergency room mortality (transfer, 3.4%; direct, 1.2%; odds ratio, 2.96; 95% CI = 1.90-4.6), and mortality after admission (transfer, 5.5%; direct, 3.6%; odds ratio, 1.57; 95% CI = 1.17-2.11). All of these differences were statistically significant (p < 0.003). Stratified and multiple logistic regression analysis did not alter these results and failed to identify a patient subgroup for which transfer was associated with a reduced risk of mortality. After adjusting for patient age, Injury Severity Score, and presence of injuries to the head or neck and extremities, transferred patients stayed significantly longer in the hospital and the intensive care unit as indicated by the mean length of stay (transfer, 16.0 days; direct, 13.2 days; p = 0.02) and the mean intensive care unit stay (transfer, 2.0 days; direct, 0.95 days; p = 0.001).

CONCLUSION

The results of this study have shown that transportation of severely injured patients from the scene directly to Level I trauma centers is associated with a reduction in mortality and morbidity. Further studies are required for the evaluation of transport protocols for rural trauma. Economic and cost-effectiveness considerations of patient triage are also essential.