A strategy for trauma debriefing after railway suicides

Following an increase in the incidence of railway suicide from an average of four events a year up to 1989 to 12 in 1990 an initiative was developed between the District Department of Clinical and Community Psychology, Exeter Health Authority and British Rail, Western Region. Traincrew leaders and management had become increasingly aware of the severity of the short- and long-term effects on drivers of experiencing a suicide. Although a management strategy had been developed over time to deal with what had been a rare phenomenon it was clear that such a dramatic increase in suicides warranted a more professional approach to debriefing and trauma counselling. This paper describes the strategies adopted by psychologists in developing an understanding of the stresses of experiencing suicides and other major incidents. The outcome of small group sessions with affected drivers is outlined. An account of the strategy developed through workshops with traincrew leaders is detailed and a three-stage debriefing (shock, search, adjustment) and follow-up protocol is discussed. This process is proposed for adoption as normal procedure following suicides or similar traumas for drivers and line managers.

MHC class II antigen processing: biology of invariant chain

The invariant chain (Ii) has been shown to play a critical role in the assembly, intracellular transport and function of MHC class II molecules. Recent studies suggest that these distinct activities can in many cases be attributed to distinct isoforms of Ii or to specific regions within it. Thus, regulation of Ii synthesis, post-transcriptional events, and post-translational modification has the potential to dramatically modulate immune responses.

Analysis of intracerebral hematoma shapes by numerical computer simulation using the finite element method

The distortion and stress distribution in the brain caused by putaminal hemorrhage were estimated by computer stimulation using the finite element method (FEM). The two-dimensional model of a single cerebral hemisphere contained cortex, white matter, caudate nucleus, lenticular nucleus, thalamus, falx, and lateral ventricle. Five types of intracerebral hemorrhage were modeled at different locations in the lenticular nucleus. The models generated putaminal hematomas of various shapes influenced by the location of the bleeding points. Hematomas caused deformation of the brain, collapse of the lateral ventricle, and destruction of the internal capsule. The stress distribution revealed various patterns influenced by the site of bleeding. The stress in the area of the internal capsule corresponded to the extent of destruction of the internal capsule. This study suggests that FEM modeling of putaminal hemorrhage can provide a useful simulation.

Preoperative assessment of skin colonization and antibiotic effectiveness in total knee arthroplasty

A bacteriologic screening procedure was performed to preoperatively assess the skin flora of 152 total knee arthroplasty patients and to determine the appropriate prophylactic antibiotic and skin-cleansing technique. Staphylococcus epidermidis resistant to standard prophylactic antibiotics was present in 4.6% of patients, whereas 44% of the patients had Staphylococcus aureus, which is poorly eradicated by standard cleansing techniques. Preoperative assessment of skin colonization has demonstrated that standard preoperative antibiotics and skin-cleansing techniques will not completely eradicate all pathogenic skin bacteria in every case. Preoperative screening effectively identifies bacterial skin flora and allows for the modification of antibiotic selection and preoperative cleansing to eradicate resistant bacterial organisms and thereby decrease the risk of postoperative prosthetic infections.

Interaction of primitive human myeloid and lymphoid progenitors with the marrow microenvironment

Primitive human hematopoietic progenitors containing a high proportion of long-term culture-initiating cells (LTCICs) are found in the 34+DR- fraction of bone marrow mononuclear cells (BMMNCs). These progenitors adhere selectively to the 33/66-kD binding domain of fibronectin and to the FN-CHII binding site, unlike more committed progenitors, which adhere less selectively to fibronectin components. These differences in adhesion to stromal components may explain selective homing and release of progenitors at varying levels of differentiation from the marrow compartment. In additional studies, we demonstrate that cultivation of primitive progenitors in a stroma noncontact long-term culture allows both differentiation of primitive progenitors and conservation of LTCICs. These observations (1) demonstrate that expansion of primitive progenitors does not require stromal contact, (2) shed light on the regulatory role of stroma in myeloid differentiation, and (3) suggest strategies for both ex vivo myeloid progenitor expansion and retrovirus gene insertion. Finally, we demonstrate that a natural killer cell population can be derived from primitive hematopoietic progenitors in a modified long-term culture model. Our findings suggest an important role for marrow stroma in lymphoid differentiation from primitive progenitors and in expression of CD2, a lymphoid marker ordinarily associated with passage of T-lymphocyte progenitors through the thymus.

Production and purification of fumonisins from a stirred jar fermenter

The production, isolation and purification of fumonisins from 10 litre liquid cultures are described. Measurements of sucrose, fructose and glucose consumption, oxygen demand, dry weight increase, CO2, and fumonisin production were taken every 48 hours. The specific productivity of fumonisins was found to be similar to that reported for corn cultures but purification was much simpler, yielding an 89% recovery. The method developed for the purification of fumonisins from liquid culture was also applied to a corn culture, resulting in a 70.1% recovery.

Chloride channel block phase advances the single-unit activity rhythm in the SCN

The mammalian suprachiasmatic nuclei (SCN) contain a circadian pacemaker that exhibits a 24 h rhythm in single-unit activity in vivo and in vitro. Chloride channel block by a saturating concentration of picrotoxin at either CT6 or CT15 produces large phase advances in the SCN single-unit activity rhythm in vitro. These phase advances are not affected by simultaneous blockade of voltage-sensitive sodium and calcium channels by TTX and magnesium. Thus, the effects of picrotoxin appear to be mediated by direct blockade of the chloride channel, rather than subsequent membrane depolarization. GABA-A receptor-mediated chloride flux may be part of the mechanism of circadian timekeeping.

Pharmacokinetic fate and pathological effects of 14C-fumonisin B1 in laying hens

Presence of fumonisin B1 (FB1), a major metabolite of Fusarium moniliforme, in corn is of great concern to both human and animal health because of its wide range of toxicity. The pharmacokinetics of FB1 was studied in laying hens following oral and intravenous administration of 14C-labelled FB1. After iv dosing (2.0 mg = 23.68 kBq/kg bw) plasma radioactivity underwent a very rapid bi-exponential decline (t1/2 alpha = 2.5 +/- 0.3 min; t1/2 beta = 48.8 +/- 11.2 min) with negligible levels measured after 4-6 hr. Mean value for the apparent volume of distribution at steady state (Vdss) was 18.27 ml/kg, apparent volume of central compartment (Vd beta) was 82.20 ml/kg and plasma clearance was 1.18 ml/min/kg. At 24 hr post-dosing only trace residues were present in liver, kidney, and cecum. When dosed by the oral route (2.0 mg = 47.36 kBq/kg bw), systemic absorption of fumonisin appeared to be poor (F = 0.71 +/- 0.5%) with peak plasma concentrations of only 40-145 dpm/ml (equivalent to 28-103 ng FB1 and/or metabolites per ml) between 1.5 and 2.5 hr. At 24 hr post-dosing only trace amounts were present in crop, liver, kidney, small intestine, and cecum. In both orally and iv dosed birds almost all (97.7 +/- 3.73%) of the radioactivity was recovered in excreta by the end of the 24 hr experiment period and no residues were found in eggs laid during the 24 hr post-dosing period.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of dose, dose-rate and particle fragmentation on cataract induction by energetic iron ions

Because activities in space necessarily involve chronic exposure to a heterogeneous charged particle radiation field it is important to assess the influence of dose-rate and the possible modulating role of heavy particle fragmentation on biological systems. Using the well-studied cataract model, mice were exposed to plateau 600 MeV/amu 56Fe ions either as acute or fractionated exposures at total doses of 5 - 504 cGy. Additional groups of mice received 20, 360 and 504 cGy behind 50 mm of polyethylene, which simulates body shielding. The reference radiation consisted of 60Co gamma radiation. The animals were examined by slit lamp biomicroscopy over their three year life spans. In accordance with our previous observations with heavy particles, the cataractogenic potential of the 600 MeV/amu 56Fe ions was greater than for low-LET radiation and increased with decreasing dose relative to gamma-rays. Fractionation of a given dose of 56Fe ions did not reduce the cataractogenicity of the radiation compared to the acute regimen. Fragmentation of the beam in the polyethylene did not alter the cataractotoxicity of the ions, either when administered singly or in fractions.

Strength training increases resting metabolic rate and norepinephrine levels in healthy 50- to 65-yr-old men

Resting metabolic rate (RMR) decreases with age, largely because of an age-related decline in fat-free mass (FFM). We hypothesized that a strength-training program capable of eliciting increases in FFM would also increase RMR in older individuals. To test this hypothesis, RMR, body composition, and plasma concentrations of certain hormones known to affect RMR were measured before and after a 16-wk heavy-resistance strength-training program in 13 healthy men 50-65 yr of age. Average strength levels, assessed by the three-repetition maximum test, increased 40% with training (P < 0.001). Body weight did not change, but body fat decreased (25.6 +/- 1.5 vs. 23.7 +/- 1.7%; P < 0.001) and FFM increased (60.6 +/- 2.2 vs. 62.2 +/- 2.1 kg; P < 0.01). RMR, measured by indirect calorimetry, increased 7.7% with strength training (6,449 +/- 217 vs. 6,998 +/- 226 kJ/24 h; P < 0.01). This increase remained significant even when RMR was expressed per kilogram of FFM. Strength training increased arterialized plasma norepinephrine levels 36% (1.1 +/- 0.1 vs. 1.5 +/- 0.1 nmol/l; P < 0.01) but did not change fasting glucose, insulin, or thyroid hormone levels. These results indicate that a heavy-resistance strength-training program increases RMR in healthy older men, perhaps by increasing FFM and sympathetic nervous system activity.

The impact of hepatitis C virus infection on renal allograft recipients

A second generation hepatitis C virus recombinant immunoblot assay (RIBA) was used to screen stored perioperative serum from 641 renal allograft recipients. One hundred and nine (17%) were anti-HCV positive at the time of transplant. RIBA positivity was found to be an independent predictor of post-transplant liver disease in a logistic regression model (P < 0.05). Moreover, RIBA positive patients were at greater risk for infectious events (P = 0.03) and rejection episodes (P = 0.002). The cumulative dose of antilymphoblast globulin administered as induction therapy was an independent predictor of post-transplant liver disease in a dose response relationship. Qualitative PCR showed that 74% of the perioperative RIBA positive patients had detectable HCV RNA in a current serum sample. Further, quantitative HCV RNA analysis with a competitive template PCR and HCV strain identification by restriction fragment length polymorphism demonstrated a large range of HCV RNA copies/ml of serum and three different HCV strains (BK, Hutch and HCV-1). Neither quantity of HCV RNA nor strain type correlated with abnormal transaminases post-transplant. As yet, there has not been an effect of anti-HCV status on actuarial patient and graft survival. This study suggests that anti-HCV is not a contraindication to renal transplantation; however, we would recommend that the pre-transplant evaluation of the anti-HCV positive patient include a liver biopsy to properly stage the disease. Close post-transplant follow-up is required in view of the increased risk for infection and rejection.

Effect of cyclosporine A on serum tumor necrosis factor alpha in new-onset type I (insulin-dependent) diabetes mellitus

Because the etiology of insulin-dependent diabetes mellitus (IDDM) is thought to be autoimmune, several clinical trials have utilized immunosuppression to treat newly diagnosed diabetic patients. In the University of Miami trial, cyclosporine A (CyA) was used to treat one group (n = 10), while the other received placebo (n = 13). During the 1-year study, islet beta-cell function was better preserved in the CyA group compared to the placebo group, based on the response (C-peptide production) to a physiologic stimulus (meal challenge). Specifically, when measured by regression analysis, the slope defining the rate of decline of beta-cell function was significantly lower for the CyA-treated group (p < 0.05). Cytokine levels were analyzed retrospectively from frozen (-70 degrees C) stored sera from both groups. At time 0, tumor necrosis factor alpha (TNF alpha) levels were similar in the CyA (40.1 +/- 14.2 pg/mL) and placebo group (38.5 +/- 12.1 pg/mL) of IDDM subjects (normal 32.0 +/- 5.0 pg/mL). At 1 month, the level of TNF alpha in the CyA group was significantly lower than that observed in the placebo group (22.3 +/- 7.2 versus 53.3 +/- 8.9 pg/mL (P < .05). TNF alpha levels subsequently fell in the placebo group and were not significantly different between placebo and CyA groups. Soluble interleukin 2 receptor (IL-2R) levels in IDDM patients were significantly higher than in normal subjects at diagnosis of IDDM. For the next 6 months, these levels fell consistently in both the CyA and placebo groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute subdural haematoma secondary to ruptured intracranial aneurysm: diagnosis and management

Acute subdural haematoma secondary to a ruptured intracranial aneurysm may lead to coma or sudden death. We describe five cases encountered in our department over the last 3 years emphasizing the differential diagnosis and approaches to management.

Role of intracranial pressure monitoring in severely head-injured patients without signs of intracranial hypertension on initial computerized tomography

Previous studies have suggested that only a small proportion (< 15%) of comatose head-injured patients whose initial computerized tomography (CT) scan was normal or did not show a mass lesion, midline shift, or abnormal basal cisterns develop intracranial hypertension. The aim of the present study was to re-examine this finding against a background of more intensive monitoring and data acquisition. Eight severely head-injured patients with a Glasgow Coma Scale score of 8 or less, whose admission CT scan did not show a mass lesion, midline shift, or effaced basal cisterns, underwent minute-to-minute recordings of arterial blood pressure, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) derived from blood pressure minus ICP. Intracranial hypertension (ICP > or = 20 mm Hg lasting longer than 5 minutes) was recorded in seven of the eight patients; in five cases the rise was pronounced in terms of both magnitude (ICP > or = 30 mm Hg) and duration. Reduced CPP (< or = 60 mm Hg lasting longer than 5 minutes) was recorded in five patients. Severely head-injured (comatose) patients whose initial CT scan is normal or does not show a mass lesion, midline shift, or abnormal cisterns nevertheless remain at substantial risk of developing significant secondary cerebral insults due to elevated ICP and reduced CPP. The authors recommend continuous ICP and blood pressure monitoring with derivation of CPP in all comatose head-injured patients.

Ground-based simulations of galactic cosmic ray fragmentation and transport

Since mean free paths for nuclear fragmentation are of the order of the ranges of primary Galactic Cosmic Ray (GCR) nuclei, determination of the radiation field produced by successive fragmentations of nuclei in material and tissue is essential to accurate assessment of GCR radiation risk to humans on long-duration missions outside the geomagnetosphere. We describe some recent measurements made at the Bevalac of heavy ion transport through materials, with representative results and examples of how they may be applied to aspects of the space radiation problem, including efforts to devise analytical tools for predicting biological effects and for designing spacecraft shielding.

Substitution of the amino acid at position 102 with polar and aromatic residues influences substrate specificity of lactate dehydrogenase

The Gln residue at amino acid position 102 of Bacillus stearothermophilus lactate dehydrogenase was replaced with Ser, Thr, Tyr, or Phe to investigate the effect on substrate recognition. The Q102S and Q102T mutant enzymes were found to have a broader range of substrate specificity (measured by kcat/Km) than the wild-type enzyme. However, it is evident that either Ser or Thr at position 102 are of a size able to accommodate a wide variety of substrates in the active site and substrate specificity appears to rely largely on size discrimination in these mutants. The Q102F and Q102Y mutant enzymes have low catalytic efficiency and do not show this relaxed substrate specificity. However, their activities are restored by the presence of an aromatic substrate. All of the enzymes have a very low catalytic efficiency with branched chain aliphatic substrates.

Management and long-term outcome following subarachnoid haemorrhage and intracranial aneurysm surgery in elderly patients: an audit of 199 consecutive cases

To address the question of managing subarachnoid haemorrhage (SAH) in the older patient, the management and outcome of 199 consecutive patients aged > or = 60 years with a confirmed diagnosis of subarachnoid haemorrhage (n = 186) or an unruptured intracranial aneurysm (n = 13) were reviewed. In seven patients, the cause of the SAH was an arterio-venous malformation and these were excluded from further analysis. Angiography was performed in 141 patients with a complication rate of 2.1%. Angiography was not performed in 51 patients and, in this cohort, the in-patient mortality rate was 68.6% and only 27.5% had a favourable outcome at discharge. Operation was not performed in 21 patients with demonstrated aneurysms for a variety of reasons. In this group, the in-patient mortality rate was 47.6% and 38.1% had a favourable outcome at discharge. Eighty-one patients in good neurological grade underwent surgery for a ruptured aneurysm and six patients underwent surgery for a symptomatic unruptured aneurysm. The surgical mortality was 1.1% and a favourable outcome at discharge was achieved in 83.9% of patients. Thirty-three patients were angiographic negative and there was a favourable outcome in 97% of this group. The management mortality in these selected patients admitted to the Department of Clinical Neurosciences was 24.4% and a favourable outcome was recorded in 66.2% of patients. Long-term follow-up (median 40 months, range 3-120 months) was obtained in 97% of discharged patients. The probability of survival at 60 months for patients in good condition at discharge was 0.826 (95% confidence interval 0.722-0.894).(ABSTRACT TRUNCATED AT 250 WORDS)

Crystallization and preliminary X-ray analysis of leukemia inhibitory factor

Leukemia inhibitory factor (LIF) is a polyfunctional molecule with significant and diverse biological activities. LIF is a glycoprotein secreted by a number of different cell types in vitro. It is induced in fibroblasts, lymphocytes, monocytes and astrocytes by various inducers such as serum, TNF, interleukin-IP and EGF. Due to extensive and variable glycosylation the molecular weight can range from 38 to 67 kDA. The biological functions of LIF are mediated through a receptor and a signal transducer, gp130, which is also used by factors like interleukin-6 (IL-6), cilliary neurotropic factor (CNTF), and oncostatin M (OSM). Here, we report the crystallization of the non-glycosylated human-like LIF expressed in E. coli. The present crystals diffract to 2.0 A using synchrotron radiation. They belong to the monoclinic space group C2, and the cell dimensions are a = 61.5 A, b = 45.3 A, c = 77.7 A and beta = 112.3 degrees.

Enhanced antigen presentation in the absence of the invariant chain endosomal localization signal

The cytosolic tail of the major histocompatibility complex class II-associated invariant chain (Ii) molecule is thought to contain the endosomal localization signal that directs and/or retains newly synthesized class II within the endosomal antigen processing compartment. To determine the role of this signal in class II transport and antigen presentation we have generated class II-positive L cell transfectants that coexpress wild type or truncated forms of Ii. Deletion of the endosomal localization signal from Ii results in rapid transport of class II-Ii complexes to the cell surface. Once at the cell surface, the complex is efficiently internalized, Ii is degraded, and class II free of Ii is recycled back to the plasma membrane. Interestingly, the truncated form of Ii is still able to increase the efficiency of antigen presentation to T cells. These data suggest that the ability of Ii to enhance antigen presentation is not limited to Golgi apparatus-endosomal sorting and raise the possibility that endocytosed class II can form immunogenic complexes with newly processed antigen.