Increased myofibroblast contractile sensitivity in paraquat pretreated rat lung tissue

In numerous tissues, contractility to certain characteristic agents is associated with cells other than muscle, e.g. actin-containing so-called myofibroblasts. Such cells are present in pulmonary interstitium of several mammalian species but their contractility has only been demonstrated from the proliferation of myofibroblasts in fibrotic lung tissues. This study has been done to evaluate such responses in normal tissues in contrast with fibrotic lungs and it was necessary to take account also of smooth muscle reactivity. Distinctive agonists: mepyramine and sodium tungstate characterised myofibroblast mediated contractility, in contrast with acetylcholine and barium chloride as specific smooth muscle stimulants. Histology and immunohistochemistry were used to evaluate the pharmacological results more precisely.

Large clonal expansions of human virus-specific memory cytotoxic T lymphocytes within the CD57+ CD28- CD8+ T-cell population

The proportion of human peripheral blood CD8+ T cells that are CD57+ CD28- is low at birth but increases with age and in individuals infected with human cytomegalovirus (HCMV) or human immunodeficiency virus (HIV). These CD57+ CD28- CD8+ T cells contain large oligoclonal T-cell expansions whose antigen specificity is unknown. We identified clonal expansions of virus-specific memory cytotoxic T-lymphocyte precursors (CTLp) in both healthy carriers of HCMV and in asymptomatic HIV-infected subjects. In each subject, from the T-cell receptor (TCR) beta-chain hypervariable sequence of each immunodominant CTL clone, we designed complementary oligonucleotide probes to quantify the size and phenotypic segregation of individual virus-specific CTL clones in highly purified populations of peripheral blood CD8+ T cells. We found large clonal expansions of virus-specific CTL clonotypes in CD57+ CD28- CD8+ T cells. Using limiting dilution analysis, we found functional peptide-specific CTLp at high frequency in CD57+ CD28- cells. Thus, memory CTL specific for persistent viruses account for many oligoclonal expansions within CD57+ CD28- CD8+ T cells.

Pathological missense mutations of neural cell adhesion molecule L1 affect homophilic and heterophilic binding activities

Mutations in the gene for neural cell adhesion molecule L1 (L1CAM) result in a debilitating X-linked congenital disorder of brain development. At the neuronal cell surface L1 may interact with a variety of different molecules including itself and two other CAMs of the immunoglobulin superfamily, axonin-1 and F11. However, whether all of these interactions are relevant to normal or abnormal development has not been determined. Over one-third of patient mutations are single amino acid changes distributed across 10 extracellular L1 domains. We have studied the effects of 12 missense mutations on binding to L1, axonin-1 and F11 and shown for the first time that whereas many mutations affect all three interactions, others affect homophilic or heterophilic binding alone. Patient pathology is therefore due to different types of L1 malfunction. The nature and functional consequence of mutation is also reflected in the severity of the resultant phenotype with structural mutations likely to affect more than one binding activity and result in early mortality. Moreover, the data indicate that several extracellular domains of L1 are required for homophilic and heterophilic interactions.

Simulated bone metastases: a case study of two patients with breast cancer

Two case studies are used to discuss topical issues current in follow-up management of patients with early stage breast cancer. These issues include the role of screening and diagnostic bone scintigraphy and patient self-advocacy in clinical management.

Human virus-specific CD8+ CTL clones revert from CD45ROhigh to CD45RAhigh in vivo: CD45RAhighCD8+ T cells comprise both naive and memory cells

It has been generally believed that human CD8+ memory cells are principally found within the CD45ROhigh population. There are high frequencies of CD8+ memory CTL specific for the human CMV tegument phosphoprotein pp65 in PBMC of long-term virus carriers; the large population of memory CTL specific for a given pp65 peptide contains individual CTL clones that have greatly expanded. In this study, we found high frequencies of pp65 peptide-specific memory CTL precursors in the CD45ROhighCD45RA- population, but also appreciable frequencies in the CD45RAhigh subpopulation. Because the majority of CD8+ T cells in PBMC are CD45RAhigh, more of the total pp65-specific memory CTL pool is within the CD45RAhigh than in the CD45ROhigh compartment. Using clonotypic oligonucleotide probes to quantify the size of individual pp65-specific CTL clones in vivo, we found the CD45RAhigh population contributed 6- to 10-fold more than the CD45ROhigh population to the total virus-specific clone size in CD8+ cells. During primary CMV infection, an individual virus-specific CTL clone was initially CD45ROhigh, but after resolution of infection this clone was detected in both the CD45ROhigh and the CD45RAhigh populations. We conclude that CD45RA+ human CD8+ T cells do not solely comprise naive cells, but contain a very significant proportion of memory cells, which can revert from the CD45ROhigh to CD45RAhigh phenotype in vivo.

Comparison of gait with and without shoes in children

Full body gait analysis was used to determine if differences exist in kinematic, kinetic, and temporal-spatial data with and without shoes in able-bodied children. The greatest difference noted between conditions was an increase in stride length with shoes. Minimal changes were seen in kinematics and kinetics with the addition of shoes. Due to the very tight standard deviations of the data, these minimal changes in the magnitude of the curves resulted in statistically significant differences, yet these changes do not appear to be clinically significant. It is believed that this study establishes that barefoot gait analysis is sufficient for most clinical studies, and an additional assessment undertaken while wearing shoes is not necessary.

Application of remedy studies to the development of a soil washing pilot plant that uses mineral processing technology: a practical experience

Soil washing employing mineral processing technology to treat radionuclide-contaminated soils has been examined as a remedy alternative to the exclusive excavation, transportation, and disposal of the soil. Successful application depends on a thorough remedy study, employing a systematic tiered approach that is efficient, self-limiting, and cost effective. The study includes: (1) site and soil characterization to determine the basic mineral and physical properties of both the soil and contaminants and to identify their relative associations; (2) treatment studies to evaluate the performance of process units for contaminant separation; (3) conceptual process design to develop a treatment pilot plant; and (4) engineering design to construct, test, and optimize the actual full-scale plant. A pilot plant using soil washing technology for the treatment of radium-contaminated soil was developed, tested, and demonstrated. The plant used particle-size separation to produced a remediated product that represented approximately 50% of the contaminated soil. Subsequently, it was modified for more effective performance and application to soil with alternate characteristics; it awaits further testing. The economic analysis of soil washing using the pilot plant as a model indicates that a remedy plan based on mineral processing technology is very competitive with the traditional alternative employing excavation, transportation, and disposal exclusively, even when disposal costs are modest or when recovery of remediated soil during treatment is low. This paper reviews the tiered approach as it applies to mineral processing technology to treat radionuclide-contaminated soils and a pilot plant developed to test the soil washing process.

Effects of six weeks of chronic ethanol administration on the behavioral outcome of rats after lateral fluid percussion brain injury

This study examined the effects of 6 weeks of chronic ethanol administration on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were given either an ethanol liquid diet (ethanol diet-groups) or a pair-fed isocaloric sucrose control diet (control diet groups) for 6 weeks. After 6 weeks, the ethanol diet was discontinued for the ethanol diet rats and they were then given the control sucrose diet for 2 days. During those 2 days, the rats were trained to perform a beam-walking task and subjected to either lateral FP brain injury of low to moderate severity (1.8 atm) or to sham operation. In both the control diet and the ethanol diet groups, lateral FP brain injury caused beam-walking impairment on days 1 and 2 and spatial learning disability on days 7 and 8 after brain injury. There were no significant differences in beam-walking performance and spatial learning disability between brain injured animals from the control and ethanol diet groups. However, a trend towards greater behavioral deficits was observed in brain injured animals in the ethanol diet group. Histologic analysis of both diet groups after behavioral assessment revealed comparable ipsilateral cortical damage and observable CA3 neuronal loss in the ipsilateral hippocampus. These results only suggest that chronic ethanol administration, longer than six weeks of administration, may worsen behavioral outcome following lateral FP brain injury. For more significant behavioral and/or morphological change to occur, we would suggest that the duration of chronic ethanol administration must be increased.

Evaluating undergraduate preclinical operative skill; use of a glance and grade marking system

OBJECTIVES

The purpose of the study was to evaluate the intra- and inter-examiner variability of a panel of examiners using a 'glance and grade' marking system when assessing Class II preparations.

METHODS

The examination panel consisted of five university staff with varying clinical and teaching experience. The panel assessed 75 disto-occlusal preparations suitable for restoration with dental amalgam prepared in extracted human premolar teeth. The majority of the preparations were cut by undergraduates in their preclinical year of study and the remainder by an experienced staff member. The panel were blind to the identity of each operator.

RESULTS

The study revealed a high degree of both intra- and inter-examiner variability, with some preparations being given a pass on one occasion and a fail on another and vice-versa. In addition, some of the panel, perhaps assuming that the practical exercise had been prepared entirely by undergraduates, were reluctant to award good grades.

CONCLUSIONS

The study has highlighted the need for better staff training and a more comprehensive system of assessing preclinical skills.

Effects of six weeks of chronic ethanol administration on lactic acid accumulation and high energy phosphate levels after experimental brain injury in rats

The effects of 6 weeks of chronic ethanol administration on the lateral fluid percussion (FP) brain injury-induced regional accumulation of lactate and on the levels of total high-energy phosphates were examined in rats. In both the chronic ethanol diet (ethanol diet) and pair-fed isocaloric sucrose control diet (control diet) groups, tissue concentrations of lactate were elevated in the cortices and hippocampi of both the ipsilateral and contralateral hemispheres at 5 min after brain injury. In both diet groups, concentrations of lactate were elevated only in the injured left cortex and the ipsilateral hippocampus at 20 min after FP brain injury. No significant differences were found in the levels of lactate in the cortices and hippocampi of sham animals and brain-injured animals between the ethanol and control diet groups at 5 min and 20 min after injury. In the ethanol and control diet groups, tissue concentrations of total high-energy phosphates (ATP + PCr) were not affected in the cortices and hippocampi at 5 min and 20 min after lateral FP brain injury. No significant differences were found in the levels of total high-energy phosphates in the cortices and hippocampi of the sham and brain-injured animals between the ethanol and control diet groups at 5 min and 20 min after injury. Histologic studies revealed a similar extent of damage in the cortex and in the CA3 region of the ipsilateral hippocampus in both diet groups at 14 days after lateral FP brain injury. These findings suggest that 6 weeks of chronic ethanol administration does not alter brain injury-induced accumulation of lactate, levels of total high energy phosphates, and extent of morphological damage.

Carboplatin dosing based on measurement of renal function--experience at the Peter MacCallum Cancer Institute

BACKGROUND

Carboplatin is used in treating many types of cancer. Because renal excretion is the major variable determining the pharmacokinetics of this drug, a dosing formula based on glomerular filtration rate (GFR) has been proposed and is being increasingly used in carboplatin dosing. This method of dosing is critically dependent on accurate measurement of GFR.

AIMS

To report the experience at a single major oncology centre of carboplatin dosing based on GFR, and comparisons of different methods of measuring renal function for use in this dosing method.

METHODS

An initial group of patients (n = 24) was studied where GFR was measured by Cr51EDTA clearance and compared to Tc99mDTPA clearance, measured 24 hour urine creatinine clearance and the Cockcroft and Gault formula. The carboplatin area under the plasma concentration versus time curve (AUC) was calculated using total platinum measured in a single blood sample assayed by flameless atomic absorption spectrophotometry. A subsequent patient group (n = 16) was then studied using Tc99mDTPA clearance to measure GFR.

RESULTS

Carboplatin dosing using Cr51EDTA clearance to measure GFR was accurate (< 25% difference between planned and measured AUC) in 87% of samples. Estimation of renal function using the Cockcroft and Gault formula correlated with Cr51EDTA clearance only in patients with GFR < 100 mL/minute. The measured 24 hour urine creatinine clearance did not correlate with Cr51EDTA clearance. Using Tc99mDTPA clearance to measure GFR, carboplatin dosing was accurate in 81% of samples. Across a GFR range of 42-239 mL/minute, the Cr51EDTA and Tc99mDTPA clearance were closely correlated (r = 0.98, slope of regression line = 1.02).

CONCLUSIONS

Carboplatin dosing using a pharmacological formula based on GFR produces accurate targeting of the carboplatin AUC. Tc99mDTPA clearance can be used to measure GFR instead of Cr51EDTA clearance, which is both more convenient and has potential cost savings. Estimates of renal function using the Cockcroft and Gault formula or measured 24 hour creatinine clearance are insufficiently accurate to use for carboplatin dosing.

Temporal and spatial characterization of neuronal injury following lateral fluid-percussion brain injury in the rat

The pattern of neuronal injury following lateral fluid-percussion (FP) brain injury in the rat was systematically characterized at sequential time points to identify selectively vulnerable regions and to determine the temporal contribution of primary and delayed neuropathological events. Male Sprague-Dawley rats (n = 28) were killed 10 min, 2 h, 12 h, 24 h, 4 days, and 7 days following a lateral FP brain injury of moderate severity (2.2 atm), or 24 h after a sham injury. Brain sections were stained and analyzed using Nissl, acid fuchsin, and silver staining methods to identify regions with injured neurons or with visible lesions. Extensive numbers of acid fuchsin or silver-stained neurons were observed as early as 10 min after the FP brain injury in regions extending from the caudate/putamen to the pons. The frequency of injured neurons was greatest in the ipsilateral cortex, hippocampus, and thalamus, and a visible loss of Nissl-stained neurons was observed in these regions beginning at 12 h after the FP brain injury. Acid fuchsin-stained neurons were restricted to the same brain regions for all of the survival periods and gradually decreased in numbers between 24 h and 7 days after injury. These findings suggest that lateral FP brain injury in the rat produces a combination of focal cortical contusion and diffuse subcortical neuronal injury, which is present within minutes of the impact, progresses to a loss of neurons by 12 h, and does not markedly expand into other brain regions with survival periods up to 7 days. Furthermore, the acute onset and rapid evolution of the neuronal injury process may have important implications when considering a window of opportunity for pharmacological intervention.

Trial-to-trial variability of corticospinal volleys in human subjects

The trial-to-trial variability of the different components of corticospinal volleys evoked by transcranial electrical stimulation of the motor cortex using a constant stimulus intensity was measured from epidural recordings during surgery to correct scoliosis. The recordings were made when there was no operative interference, and blood pressure, temperature, ventilation and anaesthetic regimen were stable. A simple D wave with a single negative peak of 10-30 microV amplitude was recorded in 4 patients. It varied little in amplitude (S.D.s < 8% for 100 consecutive single responses). In 4 patients the stimulus was adjusted to produce a complex D wave with 3 components, the earliest 2 of which arise from subcortical/brain-stem sites. The variability of amplitude of these components was high (S.D.s of 13-50%), but the variability of latency was low (S.D.s of 2-3%). Eighteen I waves were recorded in 6 of the subjects. Their variability from trial to trial was similar to that of the components of the complex D wave. It is argued that there would be greater trial-to-trial variability of the corticospinal volley in the awake state, particularly when the stimulus was magnetic rather than electrical. Explanations for changes in the compound muscle action potential produced by transcranial stimulation, electrical or magnetic, must take into account that a constant stimulus does not evoke an identical descending volley.

Kinetics of thymocyte subset development and selection revealed by cyclosporin A treatment

Cyclosporin A (CsA) inhibits the development of mature thymocytes from their CD4+ CD8+ precursors, but may allow autoreactive cells to mature. Using 3-color flow cytometry, we have followed the progressive development of thymocytes, including potentially autoreactive cells, during CsA treatment. Numbers of CD4+ CD8+ CD3high thymocytes dropped immediately, suggesting that the generation of these mature thymocyte precursors, normally dependent upon positive selection, was inhibited by CsA. Numbers of CD4+ CD8- thymocytes also declined rapidly, but CD4 - CD8+ thymocytes were unaffected for 2 days, suggesting that the mature single-positive subsets are not symmetrically derived from a common GsA-sensitive precursor. An exceptional subset of CD8 SP thymocytes, expressing CD45RA, did not respond to CsA for about 10 days, indicating that they are distantly derived from a CsA-sensitive precursor. Apoptosis of TCR-V beta 3 + thymocytes caused by Mtv-6, quantified according to the down-regulation of CD4 and CD8 on immature thymocytes, was partially inhibited by CsA, to maximal effect within 24 hours. This did not, however, facilitate their development into mature thymocytes.

Transcranial electrical stimulation of the motor cortex in man: further evidence for the site of activation

1. The motor cortex was stimulated electrically (vertex anode; cathode 6 cm lateral) in neurologically normal subjects undergoing surgery for scoliosis, and the evoked corticospinal volleys were recorded from the spinal cord using epidural electrodes. 2. Stimuli > 330 V produced a complex D-wave volley containing three separate peaks, with high-threshold components, 0.8 ms (D2) and 1.6 ms (D3), in advance of the lowest-threshold component (D1). As stimuli increased up to 1500 V, D3 replaced the later components completely, but there was no further latency 'jump'. 3. Brainstem stimulation using electrodes over each mastoid process produced a descending volley that had the same latencies as D3. At threshold, stimulation of the brainstem or spinal cord attenuated the D wave evoked by simultaneous cortical stimulation. 4. It is concluded that transcranial electrical stimulation of the motor cortex at high intensities can access corticospinal neurones at the pyramidal decussation, and that stimulation of the brainstem (and the spinal cord) preferentially accesses corticospinal axons. At threshold, motor cortex stimulation probably activates corticospinal neurones at or near the cerebral cortex.

v-mos-transformed cells fail to enter quiescence but growth arrest in G1 following serum withdrawal

The product of the mos protooncogene normally functions in the induction of meiosis and regulation of cell-cycle progression in oocytes. Here we have investigated the cell-cycle progression of NIH3T3 cells transformed by the v-mos gene. Flow cytometric analysis showed that logarithmically growing v-mos-transformed cells do not differ from their nontransformed counterparts in the distribution of cells in the G1, S, and G2/M phases. Likewise, after serum withdrawal for 48 h, both normal and v-mos-transformed NIH3T3 cells have essentially ceased proliferation, as analyzed by flow cytometry, [3H]thymidine and BrdU incorporation into newly synthesized DNA, and mitotic indexes. However, while the normal NIH3T3 cells are arrested in a quiescent state, the v-mos-transformed cells are arrested in early to mid G1, prior to the point where cells require certain amino acids for proliferation (V point). In agreement with these different arrest points, the v-mos-transformed cells enter S phase following serum stimulation within about 8 h, without the additional 4- to 6-h lag period characteristically displayed by the parental NIH3T3 cells. In addition, we show a lack of expression of a growth arrest-specific gene product, gas1, in the serum-arrested v-mos-transformed cells. These data demonstrated that v-mos-transformed cells display growth characteristics that differ fundamentally from those of normal cells or cells transformed by overexpression of myc [1]. Our results suggest that the v-mos oncoprotein transforms cells, at least in part, by preventing exit from the cell cycle into quiescence.

An approach to ventricular efficiency by use of carbon 11-labeled acetate and positron emission tomography

BACKGROUND

Positron emission tomography-derived 11C-labeled acetate kinetics have been shown to reflect myocardial oxidative metabolism. The objective of the study was to use this metabolic imaging technique in combination with an evaluation of left ventricular work as an index of ventricular mechanical efficiency.

METHODS AND RESULTS

The effects of ventricular ejection fraction and loading on this index were studied quantitatively in a canine experimental model. There was a curvilinear relationship between efficiency and the end-diastolic volume per unit mass (r = 0.84), which appeared to integrate the main determinants of left ventricular mechanical performance successfully and allowed the detection of a decreased ventricular efficiency in acute experimental heart failure.

CONCLUSIONS

This approach appears to have the potential to assess the energetic working point of the ventricle in clinical heart disease and follow the effects of therapy. The data demonstrate the feasibility of an estimate of ventricular efficiency that relies on noninvasive data-acquisition techniques.

The selection of antibodies for targeted therapy of small-cell lung cancer (SCLC) using a human tumour spheroid model to compare the uptake of cluster 1 and cluster w4 antibodies

Spheroids of a small-cell lung cancer (SCLC) cell line POC were used to evaluate the uptake and penetration of two antibodies recognising different SCLC antigens. Spheroids approximately 300-400 microns in diameter were incubated with 1 microgram ml-1 125I-labelled NY.3D11, an antibody which reacts with the cluster 1 group antigen (neural cell adhesion molecule; NCAM) and [125I]SWA11, which binds to the cluster w4 antigen. The rate of uptake of both antibodies was similar; an initially rapid phase was seen during the first 8 h and maximum uptake occurred by 24 h. The mean uptake per spheroid at 24 h was 0.97 ng for [125I]NY.3D11 and 0.45 ng for [125I]SWA11. An objective measurement of antibody penetration into spheroids was developed using a computerised image analysis of immunostained sections of spheroids. The concentration of antibody and incubation times were varied. Both antibodies penetrated the spheroids to a depth of 50 microns after 30 min. This increased to about 100 microns after 4 h incubation with 1 or 100 micrograms ml-1 SWA11. The results with 1 microgram ml-1 NY.3D11 were similar, but in the presence of 100 micrograms ml-1 NY.3D11 penetration into the spheroid was deep and diffuse. These results demonstrate a major concentration-dependent difference in the uptake and penetration of cluster 1 and cluster w4 antibodies in this spheroid model and they have implications for the selection of antibodies for targeted therapy of SCLC.