Temporal evolution of focal cerebral ischemia in the rat assessed by T2-weighted and diffusion-weighted magnetic resonance imaging.

The present study was undertaken to characterize the formation of ischemic brain edema using diffusion-weighted and T2-weighted magnetic resonance imaging in a rat model of focal ischemia. The extent of edema formation was measured from multislice diffusion-weighted and T2-weighted spin-echo images acquired at various times after ischemia. The spin-spin relaxation time (T2) and the apparent diffusion coefficient in normal and ischemic tissue were also determined. The results show that on the diffusion-weighted images the lesion was clearly visible at 30 minutes after ischemia, while on the T2-weighted images it became increasingly evident after 2-3 hours. On both types of images the hyperintense area increased in size over the first 48 hours. After 1 week the hyperintensity on the diffusion-weighted images rapidly disappeared and evolved as a hypointense lesion in the chronic phase. These results confirm the high sensitivity of diffusion-weighted MRI for the detection of early ischemia. The temporal course of the edema observed on T2W-images is in agreement with the reported increase of total water content occurring in this model. The increase of the lesion observed on the diffusion-weighted images during the first 2 days points to an aggravation of cytotoxic edema that parallels the changes in free water shown by the T2-weighted images. It is shown that the highly elevated T2's of the infarcted area several days after ischemia can substantially contaminate the diffusion-weighted images.


Topography of occipital EEG-reduction upon visual stimulation.

Visual stimuli were designed to drive a high proportion of the neurons in restricted parts of the human visual cortex. These stimuli were used to examine changes in the ongoing EEG during visual stimulation. The topographic organization of these changes was studied. It was found that the EEG from those parts of the cortex that are exposed to the stimulus is strongly reduced in amplitude. This stimulus dependency is indicative that cortical processing results itself in a reduction of the ongoing EEG, presumably due to desynchronization of neurons. The method shows that ongoing EEG can be used for functional mapping of cortical areas and is therefore valuable in situations where stimulus locked activity can not be measured.


Individual somatotopy of primary sensorimotor cortex revealed by intermodal matching of MEG, PET, and MRI.

A method for comparing estimated magnetoencephalographic (MEG) dipole localizations with regional cerebral blood flow (rCBF) activation areas is presented. This approach utilizes individual intermodal matching of MEG data, of rCBF measurements with [15O]-butanol and positron emission tomography (PET), and of anatomical information obtained from magnetic resonance (MR) images. The MEG data and the rCBF measurements were recorded in a healthy subject during right-sided simple voluntary movements of the foot, thumb, index finger, and mouth. High resolution 3D-FLASH MR images of the brain consisting of 128 contiguous sagittal slices of 1.17-mm thickness were used. MEG/MR integration was performed by superimposing the 3D head coordinate system constructed during the MEG measurement onto the MR image data using identical anatomical landmarks as references. PET/MR integration was achieved by a phantom-validated iterative front-to-back-projection algorithm resulting in one integrated MEG/PET/MR image. The estimated dipole locations followed the somatotopic organisation of the task-specific rCBF increases as evident from PET, although they did not match point-to-point. Our results demonstrate that intermodal matching of MEG, PET and MR data provides a tool for relating estimated neuromagnetic field locations to task-specific rCBF changes in individual subjects. Our method offers the perspective of refined dipole modelling.


Effect of the signal-to-noise ratio on the quality of linear estimation reconstructions of distributed current sources.

Currently, linear estimation reconstruction is the only feasible method for extracting information about spatially distributed current sources from measurements of neural magnetic fields. We present the results of a systematic study of the effect of the signal-to-noise ratio on the imaging quality of one such algorithm in over-as well as undetermined circumstances. In particular, we will discuss the necessary trade-off between the contradictory goals of a minimum norm of the reconstructed current density distribution and of a minimal deviation of the reconstructed fields from the measured fields. As an example, we show the reconstruction of a simple arrangement of two nearly parallel dipoles in two different depths inside a spherical volume conductor, discussing the differences between the computer simulation without noise and simulation with a realistic noise level.


Confidence limits for the parameter estimation in the dipole localization method on the basis of spatial correlation of background EEG.

A new residual function in the inverse problem of equivalent dipole localization methods is proposed which is based on the spatial correlation of the background EEG. This residual has the advantage that it allows the calculation of confidence limits for dipole model parameters. The method was applied to VEP data, and it was studied how the localization precision depends on the recording time of the EEG. It was found that the tangential position of an equivalent dipole can be located at 99% confidence in a region of the order 7 x 7mm for a head radius of 10cm, while the 99% confidence interval of the depth estimate is approximately 1cm, with a recording time of 20 minutes. It was also observed that an EEG recording time of more than 10-15 minutes is needed to obtain stable localization precision estimates.


Optical imaging of architecture and function in the living brain sheds new light on cortical mechanisms underlying visual perception.

Long standing questions related to brain mechanisms underlying perception can finally be resolved by direct visualization of the architecture and function of mammalian cortex. This advance has been accomplished with the aid of two optical imaging techniques with which one can literally see how the brain functions. The upbringing of this technology required a multi-disciplinary approach integrating brain research with organic chemistry, spectroscopy, biophysics, computer sciences, optics and image processing. Beyond the technological ramifications, recent research shed new light on cortical mechanisms underlying sensory perception. Clinical applications of this technology for precise mapping of the cortical surface of patients during neurosurgery have begun. Below is a brief summary of our own research and a description of the technical specifications of the two optical imaging techniques. Like every technique, optical imaging also suffers from severe limitations. Here we mostly emphasize some of its advantages relative to all alternative imaging techniques currently in use. The limitations are critically discussed in our recent reviews. For a series of other reviews, see Cohen (1989).


Temperature topography of the brain cortex: thermoencephaloscopy.

Thermoencephaloscopy (TES) - a new method of functional imaging of the cerebral cortex by its infrared radiation was advanced and developed since 1984. Improved thermovision and image processing techniques allow 2D, contact-free, dynamic and non-invasive recording of background and evoked cortical activity through an unopened skull. Activated (heated) and deactivated (cooled) zones of the cerebral cortex are revealed. The temporal resolution of TES is 40 msec (25 maps/sec), the spatial resolution is up to 70 x 70 microns/pixel. The diameter of the smallest recordable active region of the cortex is 200-300 microns. The minimal time needed for a session used for averaging of 4-9 responses varied from 40 sec up to 18 min. TES allows to detect the position, size and sequence of operation of precisely located specific cortical zones, and to measure their dynamics before, during and after sensory and direct cortical stimulation, motor acts and conditioning (associative learning). TES-effects were recorded in rats, rabbits, cats, monkeys and humans. Waves were found spreading over the cortex with a speed of up to 30 mm/sec along trajectories specific for the sensory modality and the site of stimulation. Some pathological processes in the brain are detectable by TES: experimental tumours and epileptic foci. There are many sources for local heating: neural activity, local metabolism of units, local cerebral blood flow and thermoconductivity in the activated zones of the cortex. Thermoencephaloscopy is a dynamic, non-invasive, contact-free method with a relatively high temporal and spatial resolution and sensitivity. It can be a useful tool in basic neuroscience and medicine.


Electrical impedance tomography (EIT) of brain function.

Electrical impedance tomography (EIT) is a recently developed technique which enables the internal impedance of an object to be imaged non-invasively. Images are at present reconstructed from measurements made at 51 kHz with a ring of sixteen electrodes placed around the subject. A minimum data set is acquired in 40 msec, and an image can be reconstructed in about 5 sec. The technique is rapid, safe, portable and inexpensive, and so is ideal for non-invasive continuous imaging at the bedside. It cannot be used at present to image changes in the brain with scalp electrodes, as the relative resistance of the skull is too great. It should be possible to use it in the near future with a ring of subdural electrodes to produce images of brain regions undergoing anoxic depolarization in conditions such as epilepsy or stroke. It may be possible to use it in the future to image impedance changes related either to blood flow or depolarization during functional activity. Images of depolarization could be produced with a temporal resolution of milliseconds and would form a substantial advance in neuroscience methodology.


Magnetoencephalography: a tool for functional brain imaging.

At present, one of the most promising windows to the functional organization of the human brain is magnetoencephalography (MEG). By mapping the magnetic field distribution outside the head the sites of neural events can be located with an accuracy of a few millimeters and the temporal evolution of the activation can be traced with a millisecond resolution. This paper reviews some forward field calculation approaches suitable for the interpretation of the brain's electromagnetic signals. Inverse modelling with multiple dipoles is described in detail. An example of the analysis of the somatosensory evoked-responses illustrates the potential of multiple signal classification (MUSIC) algorithm in finding optimal dipole positions.


Fibroblastic regulation of osteoblast function by prostaglandins.

The effects of osteogenic inhibitory factors secreted by human periodontal ligament fibroblasts were studied in rat bone marrow stromal cell cultures. Serum-free conditioned medium from cultures of fibroblasts strongly depressed formation of mineralized tissue by bone marrow cell cultures. The inhibitory activity was reduced by treatment of fibroblast cultures with indomethacin or by pretreatment of conditioned medium with specific antibodies to prostaglandins (PGs) E2 and F2 alpha. Passage of conditioned medium over octadecyl columns enriched PGs four-fold and significantly increased inhibitory activity. Inhibition of mineralization was replicated by treatment of bone-cell cultures with PGs B2, D2, E2, F2 alpha and I2 at concentrations of 350 ng/ml to 350 pg/ml. All combinations of these agents were inhibitory but PGE2 and PGF2 alpha exhibited the greatest inhibition at low concentrations (350 pg/ml). These experiments indicate that fibroblasts secrete PGs which can inhibit bone formation, and this may be one mechanism whereby fibroblasts can modulate osteogenesis at the interfaces of soft and mineralizing connective tissues.


Analysis of the glucose transporter content of islet cell lines: implications for glucose-stimulated insulin release.

Glucose transport across the plasma membrane of mammalian cells is mediated by a family of homologous proteins. Each glucose transporter isoform has a specific tissue distribution which relates to that tissue's demand for glucose. The beta-cells of pancreatic islets are known to express a distinct glucose transporter isoform, termed GLUT 2, which has a high Km for glucose. In this study, we examined the glucose transporter content of normal rat islets and three beta cell lines, beta-TC, HIT and RIN cells. We show that at the protein level, GLUT 2 is the only detectable transporter isoform in normal islets, and that all three cell lines also express detectable GLUT 2. In contrast, all three cell lines expressed high levels of GLUT 1, but this isoform was not detected in normal islets. Neither the native islets nor any of the cell lines expressed GLUT 3. The insulin-responsive glucose transporter GLUT 4 was detected at very low levels in beta-TC cells; to our knowledge, this is the only non-muscle or adipose cell line which expresses this isoform. We propose that the elevated level of GLUT 1 expression, together with a reduced expression of the high Km transporter GLUT 2, may account for the characteristic aberrant patterns of glucose-stimulated insulin release in cell lines derived from beta-cells.


Serum and growth factors stimulate ribosomal RNA processing in Syrian hamster embryo cells: divergence of this signalling pathway from immediate-early gene expression.

Growth factor stimulation of cells results in multiple intracellular biochemical changes including increases in calcium levels, phosphatidylinositol turnover, protein phosphorylation, immediate-early gene transcription and intracellular pH alterations. We report here that serum and growth factor stimulation of Syrian hamster embryo (SHE)-derived cell lines increases the ribosomal RNA (rRNA) processing rates. In addition, in several transformed SHE cell lines, the immediate-early response of fos/actin transcription could be separated from the immediate-early rRNA processing response. These results indicate that in these cell lines a mutation(s) which uncouples these responses has occurred. This is the first report describing (i) rRNA processing as an immediate-early effect following growth factor stimulation and (ii) the identification of a mutation(s) which can uncouple two immediate-early signalling responses.


Ins(1,4,5)P3 induces Ca2+ release from brain microsomes loaded either by the Ca2+ ATPase or by the Na+/Ca2+ exchanger.

In this study we investigated the release of Ca2+ in brain microsomes after Ca2+ loading by the Ca(2+)-ATPase or by the Na+/Ca2+ exchanger. The results show that in microsomes loaded with Ca2+ by the Ca(2+)-ATPase, Ins(1,4,5)P3 (5 microM) released 21 +/- 2% of the total Ca2+ accumulated, and that in the microsomes loaded with Ca2+ by the Na+/Ca2+ exchanger, Ins(1,4,5)P3 released 28 +/- 3% of the total Ca2+ accumulated. These results suggest that receptors of Ins(1,4,5)P3 may be co-localized with the Na+/Ca2+ exchanger in the endoplasmic reticulum membrane or that there are Ins(1,4,5)P3 receptors in the plasma membrane where the Na+/Ca2+ exchanger is normally present, or both. We also found that Ins(1,4,5)P3 inhibited the Ca(2+)-ATPase by 33.7%, but that it had no significant effect on the Na+/Ca2+ exchanger.


A negative resistance region underlies the triggering property of membrane potential in human T-lymphocytes.

Steady-state current-voltage relationships (SSCVRs) of the plasma membrane of human T-lymphocytes were studied at the physiological temperature of 37 degrees C by using the whole-cell patch-clamp technique. SSCVRs displayed a characteristic N-like shape with a negative resistance region (NRR) in a voltage range of -45 to -35 mV. The majority of cells assayed revealed SSCVR patterns crossing the V-axis at three points (in mV): V1 = -55 to -45, V2 = -40 to -35, V3 = -30 to -10. SSCVRs of T-cells activated by phytohaemagglutinin (48-96 h) also displayed NRR, but crossed the V-axis at one point only (V1 = -55 to -60 mV). It implies the possibility of two stable levels of membrane potential (V1 and V3) for the resting T-cells, but only one (V1) for activated T-cells. These data thus account for the triggering property of T-cell membrane potential previously reported. The NRR can be explained on the basis of the Hodgkin-Huxley type n4j model of K+ channel kinetics. According to the model the possibility for a membrane to have one or two stable levels of membrane potential depends on the ratio of selective K+ conductance to non-selective leaky conductance (Gk/G(leak)). The steady-state level of K+ conductance in resting T-lymphocytes proved to be sensitive to Ca2+. Buffering Ca2+ ions from either external or internal solution resulted in an appreciable increase in K+ conductance. The possibility for membrane potential to have two stable levels of membrane potential in connection with the Ca2+ dependence of K+ conductance was supposed to be important for Ca(2+)-signalling during T-cell activation.


Activation of phospholipase C by different effectors in rat placental cells.

The present communication documents the accumulation of inositol phosphates in rat placental cells by fluoride as well as by vanadate. These findings suggest the existence of the phosphoinositide pathway and its modulation by a G-protein. A concomitant action of fluoride on phosphoinositide breakdown was also observed. As is often the case in intact cells from different organs, protein kinase C exerts a feedback regulatory control on this signalling system. Gonadotropin-releasing hormone (GnRH) also stimulated the accumulation of inositol phosphates in cultured cells but no effect could be detected in freshly isolated cells. Therefore, the phosphoinositide pathway seems to be involved in the mechanism of action of GnRH in rat placental cells.


G-protein-coupled A1 adenosine receptors in coated vesicles of mammalian brain: characterization by radioligand binding and photoaffinity labelling.

A1 adenosine receptors in coated vesicles have been characterized by radioligand binding and photoaffinity labelling. Saturation experiments with the antagonist 8-cyclopentyl-1,3-[3H]dipropyl-xanthine ([3H]DPCPX) gave a Kd value of 0.7 nM and a Bmax value of 82 +/- 13 fmol/mg protein. For the highly A1-selective agonist 2-chloro-N6-[3H]cyclopentyladenosine ([3H]CCPA) a Kd value of 1.7 nM and a Bmax value of 72 +/- 29 fmol/mg protein was estimated. Competition of agonists for [3H]DPCPX binding gave a pharmacological profile with R-N6-phenylisopropyladenosine (R-PIA) > CCPA > S-PIA > 5'-N-ethylcarboxamidoadenosine (NECA), which is identical to brain membranes. The competition curves were best fitted according to a two-site model, suggesting the existence of two affinity states. GTP shifted the competition curve for CCPA to the right and only one affinity state similar to the low affinity state in the absence of GTP was detected. The photoreactive agonist 2-azido-N6-125I-p-hydroxyphenylisopropyladenosine ([125I]AHPIA) specifically labelled a single protein with an apparent molecular weight of 35,000 in coated vesicles, which is identical to A1 receptors labelled in brain membranes. Therefore, coated vesicles contain A1 adenosine receptors with similar binding characteristics as membrane-bound receptors, including GTP-sensitive high-affinity agonist binding. Photoaffinity labelling data suggest that A1 receptors in these vesicles are not a processed receptor form. These results confirm that A1 receptors in coated vesicles are coupled to a G-protein, and it appears that the A1 receptor systems in coated vesicles and in plasma membranes are identical.


'Cross-talk' between phospholipase C and adenylyl cyclase involves regulation of G-protein levels in GH3 rat pituitary cells.

We have investigated the possibility that adenylyl cyclase (AC) activity and membrane protein levels of the alpha-subunits of the stimulatory and inhibitory G-proteins of AC (Gs alpha and G(i)-2 alpha) in cultured prolactin-producing rat pituitary adenoma cells (GH3 cells) are modulated by phospholipase C (PLC)-generated second messengers. Pretreatment of cells (6-48 h) with ionomycin (1 microM) or 1-oleoyl-2-acetylglycerol (OAG; 1 microM) showed that ionomycin regulated Gs alpha levels in a time-dependent, biphasic manner; a two-fold increase followed a 40% initial reduction, while OAG lowered Gs alpha levels by more than 50% at all time-points. G(i)-2 alpha levels remained unchanged by both pretreatments. OAG, but not ionomycin, increased basal AC activity without increasing enzyme protein levels. Alterations in AC responsiveness to peptide hormones (e.g. thyroliberin and vasoactive intestinal peptide) correlated to membrane Gs protein alpha-subunit content. These results demonstrate the involvement of G-protein translation regulation as one mechanism of 'cross-talk' between the PLC- and AC-dependent signalling pathways.


Characterization of endogenous substrates for novel-type protein kinase C as well as conventional-type protein kinase C in primary cultured mouse epidermal cells.

In primary cultured mouse epidermal cells, phorbol 12-myristate 13-acetate (PMA), which activates protein kinase C (PKC), induced changes in the phosphorylation levels of 10 proteins, termed KP-1 to -10, in two-dimensional PAGE. Seven of these proteins were phosphorylated and three were dephosphorylated. Similar changes were induced by other PKC activators, but not by inactive phorbol ester. Among these substrate proteins, phosphorylation of three proteins, i.e. KP-1 (pI 4.7/23,000 M(r)), KP-2 (pI 4.7/20,700 M(r)) and KP-10 (pI 4.7/25,500 M(r)) was markedly enhanced by PMA and inhibited by a potent PKC inhibitor staurosporine. In vitro phosphorylation studies and phosphoamino acid analysis, using these proteins as substrate and PKC preparations obtained from epidermal cell lysate, revealed that KP-1 and -2 were directly phosphorylated by Ca(2+)-, phospholipid-dependent protein kinase (conventional-type PKC; cPKC), but not by Ca(2+)-independent, phospholipid-dependent protein kinase (novel-type PKC; nPKC). On the other hand, KP-10 was mainly phosphorylated by nPKC in intact epidermal cells. These results indicate that cPKC and nPKC in epidermal cells have different substrate specificity for endogenous proteins and may induce different signal transduction.


Activation of solubilized G-proteins by muscarinic acetylcholine receptors.

Binding of GTP and its analogue, guanosine 5'-O-[gamma-thio]triphosphate (GTP[S]) to G-proteins, and release of GTP[S] from G-proteins are stimulated by muscarinic acetylcholine (mACh) receptors in intact cardiac membranes. Upon solubilization of receptors and G-proteins by membrane extraction with the detergent, 3-[(cholamidopropyl)dimethylammonio]-1-propanesulphonate, followed by sucrose density gradient centrifugation, agonist-liganded mACh receptors stimulated binding of GTP[S] and hydrolysis of GTP by G-proteins with similar requirements as in intact membranes. One soluble agonist-activated mACh receptor induced binding of GTP[S] to several (about seven) soluble G-proteins. In contrast to intact membranes, however, agonist activation of mACh receptors did not induce release of GTP[S] from solubilized G-proteins. The data presented indicate that mACh receptors can interact with and efficiently activate G-proteins even in solution, whereas the possible interaction of receptors with GTP[S]-liganded G-proteins observed in intact membranes is lost upon solubilization of these components.


Activation of phospholipase D by endothelin-1 and other pharmacological agents in rabbit iris sphincter smooth muscle.

The stimulation of phospholipase D (PLD) activity by endothelin-1 (ET1) was investigated in rabbit iris sphincter prelabelled with [3H]myristic acid. In the presence of 0.5% ethanol, ET1 caused a time- and dose-dependent increase in the production of [3H]phosphatidylethanol ([3H]PEt). Within 30 s the peptide increased PEt formation by 30% and after 5 min increased it by 140%. The EC50 value for ET1-stimulated PEt formation was found to be 30 nM. This value is appreciably lower than the EC50 we previously obtained for ET1-induced inositol trisphosphate production (45 nM), but considerably higher than that for arachidonic acid release (1 nM). PEt formation was significantly stimulated by prostaglandin F20, phorbol 12,13-dibutyrate (PDBu), chloroform, A23187 and A1F4-, but it was not affected by carbachol or the platelet-activating factor. PDBu-stimulated PEt formation was blocked by staurosporine and it was not potentiated by A23187. Staurosporine had no effect on ET1-stimulated PEt formation. Our data indicate that ET1 stimulation of PLD occurs independently of protein kinase C activation, phospholipase C activation and intracellular Ca2+ mobilization, and phospholipase A2 activation. In this tissue the ET1 receptor is probably coupled to the three phospholipases through several G-proteins, and this appears to be species and receptor type specific.


A gating 31P NMR method triggered by pulses for cardiac pacing.

A new gating NMR technique triggered by pulses for the cardiac pacing of isolated, perfused rat heart is described. This technique is suitable for obtaining spectra at the same positions over the cardiac cycle with the same RF pulse repetition time and with constant heart rate. Accordingly, each recovered magnetization level at these positions during the cycle can be kept constant. It also allows a qualitative analysis of the myocardial energy level during the cycle under the condition of the same or different cardiac workload (rate pressure product, HR x LVP). This method was used to observe cyclical changes in the concentration of adenosine triphosphate (ATP), phosphocreatine (PCr), P(i), and in pH during the cardiac cycle, and confirmed that the levels of ATP and PCr showed reversible decreases, and P(i) showed an antiphasic increase at the peak systole. On the other hand, no significant changes in pH were noted during the cardiac cycle. This pacing-gated technique is an improvement over other gated NMR techniques triggered by the blood pressure or by ECG traces.


Absolute quantification of 31P liver metabolites in rat using an external reference and a surface spoiling magnetic field gradient.

A simple method for measuring absolute concentrations of 31P metabolites in rat liver using an external reference is described. It neutralizes systematic errors due to conductive losses by calibration of the matching capacitor and selects liver signals via an electrically driven, surface spoiling magnetic field gradient. The technique avoids the chemical shift problems associated with linear field gradient localization methods at 4.7 T and allows combination with the double standard method for absolute metabolite concentration determination. Application of the method to the in vivo measurement of the absolute concentrations of ATP and P(i) in eight rat livers yields results that are in good agreement with literature values. Absolute phosphomonoester concentrations were also obtained, but no literature data were available.


First principles of fast spin echo.

Fast spin echo (FSE), a variant of the rapid acquisition with refocused echoes pulse sequence, is now being widely considered as an alternative to conventional spin echo for proton density and T2-weighted imaging. Although the medical experience with this sequence is relatively limited, relevant aspects of the technique have been well understood in the context of spectroscopic applications for many years. This article attempts to portray the subject in an appropriate historical context. Such a viewpoint promotes a deeper understanding of the artifacts, determinants of contrast, and future evolution of FSE. Hopefully, this may not only be of benefit in the design of optimal clinical imaging protocols for current state of the art but may also be of use in fashioning the criteria by which new developments in this field may be judged.


Magnetic resonance evaluation of stroke.

Stroke is not a specific disease but is, instead, a symptom complex reflecting destruction of brain tissue by cerebrovascular disease. Several different specific diseases are included in the "stroke" category, including intra- and extracerebral hemorrhage as well as ischemic infarction. These different types of stroke have major differences regarding etiology, management, and prognosis. The goal of stroke imaging is to diagnose the type of stroke at clinical presentation, allowing prompt and appropriate management. Magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), and magnetic resonance spectroscopy (MRS) provide powerful noninvasive means to evaluate the pathologic and metabolic changes that occur in acute stroke. These techniques allow the early detection of stroke and greatly increase the ability to determine the etiology of the stroke. One or more of these methods will surely become a standard means of evaluating acute stroke. The information provided, combined with new stroke therapies, should result in improved patient outcome.


An assessment of 31P MRS as a method of measuring pH in rat tumours.

The contribution of extracellular components to the measurement of pHMRS of a variety of rat tumours (nitrosomethyl urea induced mammary tumours, GH3 prolactinomas, Hepatoma 9618a, UA hepatomas and Walker sarcomas) has been assessed. Acid extractable P(i) was between 2.6 and 12.5 mumol/G wet wt depending on tumour type, and of this 53 +/- 4.8% (mean +/- SEM) was MRS-visible. The P(i) content of tumour exudate was 2-3 mM, of interstitial fluid (sampled from a micropore chamber incorporated within a tumour) 1.7 mM, and of blood plasma 1.95 mM. The mean extracellular volumes of the tumours, measured by distribution of 3H2O and [14C]inulin, were 49-55% depending on tumour type and were at least twice that found in normal liver. Calculations suggested that for most tumours with an extracellular volume not exceeding 55%, at least 65% of the P(i)(MRS) signal was derived from intracellular P(i), and thus that pH(MRS) is a measure of pHi. For each tumour type, pHMRS was measured both in 'pulse-acquire' mode at 1.9 T which may include signals from surrounding tissue, and in localized mode at 4.7 T where the signal came uniquely from tumour tissue. The steady state pHMRS was either neutral or on the alkaline side of neutrality (pH range 7.04-7.37). Raised lactate content and decreased buffering capacity (compared to normal tissues) accompanied these neutral to alkaline pH values.(ABSTRACT TRUNCATED AT 250 WORDS)


Chemical exchange in tissue extracts revisited: bicarbonate and deuterium isotope effects on 31P resonances of phosphoethanolamine and phosphocreatine.

It is not sufficiently appreciated that chemical exchange can markedly affect the appearance of 31P tissue extract NMR spectra. In addition to the commonly recognized 31P chemical shift effects of divalent metal cation (e.g. Mg2+) binding upon ATP resonances, multiple resonances for phosphoethanolamine (PE) and phosphocreatine (PCr) are observed under certain conditions of pH, temperature, and D2O and bicarbonate concentrations. In the presence of bicarbonate ion (commonly used to neutralize acidic extractions) carbamate formation causes a second 31P resonance for PE to appear. This effect has been described previously for 13C and 1H amino acid resonances in tissue extracts [Sherry et al. J. Magn. Reson. 89, 391-398 (1990)]. The observation of a splitting of the PCr 31P resonance in aqueous solutions containing D2O has been recently ascribed to proton scalar coupling but was described earlier in an underappreciated report [Kupriyanov et al. Biochem. Biophys. Res. Comm. 114, 1117-1125 (1983)] as due to a deuterium isotope effect. These effects, carbamate formation and deuterium isotope shift, are verified herein to cause marked shifts in PE and PCr 31P resonances. The dependence upon experimental parameters is explored.


Comparison of pH measurements made using 31P NMR and a fibreoptic pH meter.

The objective of this study was to compare pH measurements made in biological samples using 31P NMR (pHNMR) with those made with a novel, dye-based fibreoptic pH measurement system (pHF), which is compatible with use in electromagnetic fields without field perturbation. Using protein-free model solutions, pHNMR was calibrated against pHF, giving a correlation coefficient of 0.969 and a mean difference (+/- SD) between pHNMR and pHF of 0.037 +/- 0.054 over the pH range 6.8-7.7. Further calibration of pHNMR with pHF was carried out for human red blood lysates and then pHNMR was compared with pHF for whole, packed red blood cells over the pH range 7.0-7.8. Values for pHNMR, the intracellular pH, were consistently lower than for pHF, the extracellular pH, by a mean (+/- SD) of 0.15 +/- 0.02 units. A close correlation of extracellular pHNMR with pHF was demonstrated for a blood sample exhibiting two P(i) peaks, over the pH range 7.03-7.71. We conclude that concurrent use of NMR and the fibreoptic pH meter provides a reliable method of simultaneous measurement of intracellular and extracellular pH in biological systems.


A new high sensitivity 19F probe for labeling cysteine groups of proteins.

A novel iodoacetamide label 4-perfluoro-tert-butyl-phenyliodoacetamide (PFP) containing nine fluorine atoms in equivalent positions has been synthesized. It provides a homogeneous 19F NMR resonance line which can be detected with high sensitivity when coupled to proteins. As an example, the sulfhydryl groups of actin have been labeled with PFP; < 100 nmol of this medium sized protein (corresponding to 2.5 mL of a 40 microM solution) can be detected easily in a single scan at 470 MHz.


Learning disabilities: community nutrition.

Nutrition for people with learning disabilities living in the community is an aspect of care that should not be taken for granted. From clients who live virtually independently to those living in fully staffed homes, there is much to be gained from a thorough assessment of their eating patterns. This article reviews the most common nutritional problems such clients face and discusses ways of overcoming them.


A nurse practitioner rheumatology clinic.

The author describes the background to the establishment of nurse practitioner clinics at Leeds General Infirmary, which combine the skills of nurses with medical input to provide care for rheumatology patients. The model used is based on patient knowledge, and the author stresses that one of the primary functions of the nurse practitioner is that of educator. She also highlights the importance of research within the nurse practitioner role and concludes that nurses can deliver high quality care from nurse-led rheumatology clinics.


Occupational health. Manual handling: proposed regulations.

Injuries associated with manual handling operations account for most workplace injuries reported to the Health and Safety Executive and local authorities. In the health care services, they account for almost 50 per cent of all injuries reported under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RlDDOR) of 1985 (1). This article examines how proposed legislation may be applied to make the industry safer, drawing on work being carried out by some health authorities and organisations such as the Back Pain Association and WING (The Work-Injured Nurses Group of the Royal College of Nursing). The author draws on EC directives, and on consultative documents on the proposed regulations issued by the Health and Safety Executive (2), as well as draft guidance issued by the Working Party of the Health and Safety Commission's Health Services Advisory Committee (1).


The influence of pigmentation and illumination on the perception of erythema.

The visual assessment of erythema induced by ultraviolet radiation (UVR) involves a comparison of the irradiated site with surrounding nonirradiated skin. By viewing the skin through plastic filters of varying shades of brown to simulate different degrees of pigmentation and under either incandescent or fluorescent lighting, we were able to examine the influence of pigmentation and illumination on the perception of erythema. Illuminating the skin with either light source at the same illuminance did not affect the determination of the minimal erythema dose (MED). Likewise, the range of pigmentation that may occur in Caucasian skin had little or no effect on the perception of the MED compared with white, untanned skin. However, when the skin was viewed through dark brown filters that approximate the absorbance of Negro skin, erythema was only perceived at sites that had been irradiated with more than about twice the MED.


A comparison of the ultraviolet B-induced erythemal response of back and buttock skin.

Thirty-six subjects (dermatology patients and normal volunteers) were phototested on back and buttock skin to determine their erythemal response to a geometrically increasing series of doses of ultraviolet B (UVB) radiation. The minimal erythema doses (MED) were recorded at 24 h post-irradiation and dose-response curves were constructed. A significant difference in MED was found between the 2 sites, with a higher value for buttock skin (median 38 mJ/cm2) than for the back (median 25 mJ/cm2). The slopes of response for the 2 sites were, however, found to be comparable, and there was no correlation between the slope of dose response and sun-reactive skin type at either site. Buttock skin, representing the constitutional skin colour, may provide a useful site for phototesting, especially in otherwise tanned individuals, providing that full dose-response curves are analysed.


The effect of topical L-selenomethionine on minimal erythema dose of ultraviolet irradiation in humans.

The purpose of this study was to determine whether topical L-selenomethionine reduces the degree of acute damage to the skin (i.e., sunburn) induced by ultraviolet (UV) irradiation in humans. Eight women volunteers were treated for 2 weeks first with lotion vehicle then with topical L-selenomethionine for two weeks at each of three concentrations (0.002%, 0.02%, and 0.05%). At the end of each 2-week treatment period, the minimal erythema dose (MED) of UV irradiation was measured using a Multiport Solar Ultraviolet Simulator. It was found that topical L-selenomethionine was effective in protecting against acute UV damage to the skin. A response curve demonstrated that increasing concentrations of topical L-selenomethionine gave increasing MED, with a plateau of maximal protection attained at a concentration between 0.02% and 0.05%. Although previous studies in rats and mice demonstrated percutaneous absorption of selenium after application of L-selenomethionine, in the concentrations used here, the topical L-selenomethionine did not result in increased levels of selenium in the blood plasma of the patients tested.


In vitro kinetics of 8-methoxypsoralen penetration into human lymphoid cells.

Extracorporeal photochemotherapy (ECPC) requires ex vivo UVA irradiation of blood lymphocytes during the time of the theoretical peak 8-methoxsalen (8-MOP) concentration. The aims of this study were to determine the mechanism of cellular uptake of 8-MOP, its possible saturation and the time needed to reach maximal concentration (Tmax) in lymphoid cells. 8-MOP was measured by liquid chromatography in the supernatant of lymphoid cell suspensions incubated with a known amount of 8-MOP. The kinetics of cellular uptake were determined and showed that equilibrium had already been reached after 2 min and remained constant for at least 60 min. The uptake was independent of temperature (4, 25 and 37 degrees C) and was proportional to the 8-MOP concentration in the supernatant. This indicated that 8-MOP penetrated into lymphoid cells by passive diffusion, rather than by active transport or facilitated diffusion, and was thus a non-saturable process. In addition, intracellular metabolism was negligible. These findings demonstrated that the plasma and lymphocytic Tmax were reached simultaneously and statistical analysis showed them to be significantly correlated, thereby validating the standard ECPC protocol for drug ingestion and lymphocyte irradiation.


Demonstration of olaquindox phototoxicity in vitro.

Olaquindox is an oral anti-bacterial agent used as an additive to animal food. It is known to cause photosensitization in pig breeders, probably due to a photoallergic mechanism. Also, olaquindox was found to be phototoxic in animal experiments. We have evaluated the phototoxic properties of olaquindox in vitro with a photohemolysis test using different light sources. Irradiation with a source rich in ultraviolet A (UVA) and, to a lesser degree, with a lamp emitting mainly visible light induced photohemolysis, which depended on the concentration of olaquindox and the radiation dose. Exposure to radiation rich in UVB caused no olaquindox-dependent hemolysis. The absorption spectrum of olaquindox changed prominently after irradiation, indicating photodegradation of the compound.


Colorimetric assessment of the effects of azelaic acid on light-induced skin pigmentation.

A 20% azelaic acid (AZA) cream is currently used as a therapeutic agent in the treatment of acne vulgaris. Therefore, this product is intended to be applied on frequently or continuously sun-exposed skin. In certain disorders of hyperpigmentation, AZA has been reported to have a depigmenting effect as well, while showing no significant activity on normal skin. It has been suggested that AZA selectively inhibits hyperactive or malignant melanocytes. Knowing that light-stimulated melanocytes are in a state of hyperactivity, it seemed worthwhile to investigate AZA activity on light-induced skin pigmentation. This study aimed to assess the activity of 20% AZA cream on light-induced skin pigmentation in 10 subjects. There were 5 test zones, all located on the middle of the back: 2 were treated with AZA cream, 2 others with the vehicle and 1 was left untreated. Each product was applied twice daily, 5 days a week, for 4 weeks on one zone, and for 5 weeks on the other. In the middle of the fourth week, the tested zones were exposed to ultraviolet B (UVB) + UVA + visible light, with a total of 3 times the minimal erythema dose distributed progressively over 3 consecutive days. Seven and 10 days after the last irradiation, the induced photopigmentation was assessed by colorimetric and visual means. Compared with its vehicle, the AZA cream had neither a depigmenting effect nor a preventive effect on the light-acquired skin pigmentation. Moreover, interrupting or continuing the AZA treatment after skin irradiation had no influence on the resulting pigmentation.


Trend analysis of solar ultraviolet exposure of the Austrian population caused by holiday patterns since 1969.

Over the last few decades, a steady increase in the incidence of skin cancer has been observed. Solar ultraviolet (UV) exposure is undoubtedly one of the primary causes, and of these, holiday patterns are an intrinsic component. To assess solar UV exposure for this trend analysis, changes in holiday patterns were investigated. For Austrians, a preponderance of holidays are spent at the Mediterranean Sea. These holidays represent not only a potentially high UV exposure because of location but also because sun-intensive activities are preferred. The analysis shows an increase in solar UV exposure from all holidays of 1.6% per year. About 22% of the population spends holidays at the Mediterranean Sea, and UV exposure of the total population from these holidays has increased annually by about 3.3%. Because of the latency period, it is not possible to draw conclusions from the increase in UV exposure and the temporal trends in skin cancer. A longer time series would be necessary to do this. A direct comparison of data from other countries reporting increases in skin cancer does not seem appropriate, as levels of UV exposure vary greatly and such factors as genetic susceptibility are involved.


Photosensitivity induced by quinidine sulfate: experimental reproduction of skin lesions.

A case of quinidine sulfate-induced photodermatitis is reported. The photosensitive reaction to quinidine sulfate was reproducible in the photopatch test and after oral intake plus ultraviolet A (UVA) irradiation. Eczematous dermatitis was provoked after intradermal injection of in vitro UVA-irradiated quinidine sulfate only in the presence of patient's serum. The clinical picture and histology suggest an allergic reaction. The photobinding of quinidine sulfate to a potential carrier protein in skin or serum seems to be of crucial importance for this type of photodermatitis. Quinidine sulfate is frequently used as an antiarrhythmic drug. Its potential as a photosensitizer should always be considered.


Comparison of the antipsoriatic efficacy of heliotherapy and ultraviolet B: a cross-over study.

Ten psoriasis patients who underwent a 4-week heliotherapy period in the Canary Islands were treated with ultraviolet B (UVB) phototherapy at relapse, 2-24 months later. In both settings, psoriasis improvement was monitored using a psoriasis severity index (PSI), and UV exposure was recorded with polysulphone films. In the 8 patients that could be evaluated, a median healing rate of 94% was recorded in the heliotherapy period, with a median cumulative UV dose of 46 erythemal units (EU). In the UVB phototherapy, a median improvement rate of 86% was found after a median cumulative UV dose of 112 EU. It is concluded that, on an erythemal UV dose basis, heliotherapy was more effective than UVB phototherapy in treating psoriasis.


Enoxacin-induced photosensitivity: study of two cases.

Enoxacin is a second-generation quinolone derivative recently introduced in Spain. Its activity comes through the inhibition of bacterial DNA-gyrase and it has a good antibacterial capacity against a broad spectrum of gram-positive and gram-negative bacteria. It is presumed to be less toxic than the rest of the quinolones and its use is increasing, specially to treat infections of the urogenital tract. Cases of photosensitivity to enoxacin have been very rarely reported. We describe 2 patients with photosensitivity reactions due to this drug.


The mouse Enhancer trap locus 1 (Etl-1): a novel mammalian gene related to Drosophila and yeast transcriptional regulator genes.

A novel mouse gene, Enhancer trap locus 1 (Etl-1), was identified in close proximity to a lacZ enhancer trap integration in the mouse genome showing a specific beta-galactosidase staining pattern during development. In situ analysis revealed a widespread but not ubiquitous expression of Etl-1 throughout development with particularly high levels in the central nervous system and epithelial cells. The amino acid sequence of the Etl-1 protein deduced from the cDNA shows strong similarity, over a stretch of 500 amino acids, to the Drosophila brahma protein involved in the regulation of homeotic genes and to the yeast transcriptional activator protein SNF2/SWI2 as well as to the RAD54 protein and the recently described helicase-related yeast proteins STH1 and MOT1. Etl-1 is the first mammalian member of this group of proteins that are implicated in gene regulation and/or influencing chromatin structure. The homology to the regulatory proteins SNF2/SWI2 and brahma and the expression pattern during embryogenesis suggest that Etl-1 protein might be involved in gene regulating pathways during mouse development.


Transient and recurrent expression of the Egr-1 gene in epithelial and mesenchymal cells during tooth morphogenesis suggests involvement in tissue interactions and in determination of cell fate.

We have analyzed the expression of early growth response gene (Egr-1) by mRNA in situ hybridization during mouse embryonic tooth development and in experimental recombinations of dental epithelium and mesenchyme. Egr-1 was transiently and recurrently expressed both in epithelial and mesenchymal cells starting from day 13 of gestation and up to 4 days after birth. The expression correlated with developmental transition points of dental mesenchymal and epithelial cells suggesting a role for Egr-1 in sequential determination and differentiation of cells. In recombination cultures of early dental epithelium and mesenchyme Egr-1 RNA was localized at the epithelial-mesenchymal interface in mesenchymal cells, and in two cases also in epithelial cells. These data indicate that Egr-1 expression may be regulated by epithelial-mesenchymal interactions when they are specific enough to initiate differentiation. We have also analyzed by in situ hybridization whether Wilms' tumour-1 gene (wt-1) is expressed in the developing tooth as it was proposed on the bases of in vitro studies that it may inhibit Egr-1 expression. No wt-1 expression was detected at any stage of tooth development showing that wt-1 is not obligatory for regulation of Egr-1 expression.


Nuclear transport and phosphorylation of the RNA binding Xenopus zinc finger protein XFG 5-1.

XFG 5-1 is a Krüppel-type Xenopus zinc finger protein with specific RNA homopolymer binding activity in vitro. In the oocyte, the protein is distributed between nucleus and cytoplasm; the nuclear fraction, not the cytoplasm, contains phosphorylated isoform(s) of XFG 5-1. In vitro phosphorylation by use of oocyte/egg extracts or purified casein kinase II is specific to the amino-terminal portion of the protein. The carboxy-terminal zinc finger domain contains a signal sufficient for nuclear transport. Overexpression of either full length XFG 5-1 or of the carboxy-terminal portion alone, which maintains RNA binding and nuclear import activities, was achieved in Xenopus embryos by mRNA injection. This treatment did not result in impaired regulation of development, suggesting that XFG 5-1 functions in a way distinct from the mode of action exemplified in the Drosophila zinc finger protein Krüppel.


Characterization, specificity, and IgV gene usage of anti-lymphocyte monoclonal antibodies from perinatal mice.

Previous studies have shown that CD5+ B cells predominate during development of the immune system and frequently secrete self-reactive antibodies, some of which appear to influence the development of the adult B cell repertoire. In addition, we now show that a high frequency of perinatally derived antibodies react with lymphocytes. Hybridomas derived from perinatal liver and splenic B cells and from spleens of adult BALB/c and C57BL/6 mice were screened by immunofluorescence on thymocytes. Anti-lymphocyte antibodies, all of the IgM isotype, were detected at a high frequency from perinatal fusions, but none were obtained from adult mice. These anti-lymphocyte mAbs were heterogeneous because they stained different subsets of peripheral T and B lymphocytes. Although the antigens recognized by these mAbs were heterogeneous with respect to their sensitivity to a variety of enzymes, 13 of the 19 mAbs recognized epitopes which were modulated by phosphatidylinositol-phospholipase C treatment. Inhibition experiments suggested that six of these 13 mAbs shared the same molecular specificity, and that they recognized the same T cell subset (62% of CD4+ and 98% of CD8+ cells). Furthermore, three of these mAbs immunoprecipitated the same 100 kDa protein from thymocytes (70 kDa in reducing conditions). The related molecular specificity of some anti-lymphocyte mAbs was also reflected by their restricted V gene usage. Three of the five mAbs specific for the 100 kDa protein used very similar or identical germline SM7 VH genes. In addition to using the same germline D and JH genes, they also exhibited identical VH-D-JH joins, despite originating from distinct fusions. Analysis of light chains also showed some restriction by preferential use of germline V kappa 4 and J kappa 5 genes. Together, these results suggest that the restricted antibody repertoire characteristic of mouse fetal and neonatal B cells is also reflected in the production of anti-lymphocyte antibodies. These B cells appear consistently in early development, use germline V genes, and express a characteristic VH-D-JH join.


Patterns of responsiveness of T cell lines and thymocytes reveal waves of specific activity in the post-natal murine thymus.

Antibody binding of CD3, CD4, or CD8 molecules can induce cytoplasmic calcium mobilization in T lymphocytes, usually interpreted as indicating signal transduction. Using such assays, in a CD4+ CD8+ thymocyte line and its single positive progeny we have identified characteristic patterns of responsiveness that are reproducible in vivo in a subpopulation of newborn 'double positive' thymocytes but virtually absent in adult thymuses. In particular, these cells appear to be high responders to the binding of anti-CD3 F(ab)'2 fragments. We have followed the presence of such highly responsive thymocytes in the perinatal period and the first 15 days of life. Intriguingly, these cells populate the newborn thymus in three distinct waves. Such patterns of responsiveness may define early 'selectable' thymocytes.


Polyreactive IgM antibodies generated from autoimmune mice and selected for histone-binding activity.

A panel of histone-reactive IgM mAbs was obtained from mice belonging to various spontaneously autoimmune strains. Most of these antibodies were polyreactive, i.e. they showed binding to other cationic antigens (poly-L-lysine, lysozyme, cytochrome c) or to cytoskeletal proteins (actin, myosin, vimentin). The variable regions of these antibodies were encoded by V genes and gene segments belonging to various families. Their H chain third hypervariable regions were unusual in that the D segments were read in all three possible reading frames in contrast to most conventional antibodies and other polyreactive antibodies obtained from normal mice.


Reconstitution of the intermediate-affinity interleukin-2 receptor by cell fusion.

Although IL-2 receptor beta chain (IL-2R beta) expressed in various lymphoid cell lines binds IL-2 with an intermediate affinity, IL-2R beta expressed in fibroblasts is unable to bind IL-2, suggesting that IL-2R beta is on its own not sufficient for generating the intermediate-affinity receptor and that lymphoid-specific regulatory control may be operated to allow IL-2R beta to bind IL-2. In the present study, we observed that human IL-2R beta expressed in a mouse myeloma X63-Ag8.653 (X63) by cDNA transfection did not bind IL-2, while the same IL-2R beta expressed in an IL-6-dependent mouse B cell hybridoma F12-28, which was obtained by cell fusion between X63 and lipopolysaccharide (LPS)-induced lymphoblasts, bound IL-2 with the intermediate affinity. Interestingly, when the human IL-2R beta cDNA-transfected X63 clone, which by itself manifests no IL-2 binding, was fused with LPS-induced lymphoblasts, the resultant hybridomas manifested intermediate-affinity IL-2 binding. The IL-2 binding was specifically inhibited by addition of antihuman IL-2R beta mAb (Mik-beta 1) but not by mAb against mouse IL-2R subunits, indicating that human IL-2R beta was responsible for the IL-2 binding, i.e. non-functional human IL-2R beta in X63 was converted to competent IL-2R beta by complementation with a mouse spleen cell-derived factor(s) through the cell fusion. Cross-linking experiments with [125I]IL-2 revealed the presence of a 61 kDa protein other than IL-2R beta in cells expressing the intermediate-affinity IL-2R.(ABSTRACT TRUNCATED AT 250 WORDS)


The appearance and role of gamma delta T cells in the peritoneal cavity and liver during primary infection with Listeria monocytogenes in rats.

We have previously reported that gamma delta T cells play important roles in protection during the early stage of infection with Listeria monocytogenes in mice. To generalize the protective roles of gamma delta T cells in listerial infection to different species, we examined the appearance of gamma delta T cells during infection with L. monocytogenes in Fisher F344 rats. The numbers of bacteria in the peritoneal cavity and liver increased to a maximum level on day 3 and then decreased to an undetectable level by day 10 after an intraperitoneal infection with a sublethal dose (1 x 10(8)) of viable L. monocytogenes in rats. CD3+ alpha beta- T cells in the peritoneal cavity and liver began to increase on day 3, reached a maximum level on day 6, and thereafter decreased gradually by day 10 after infection. Northern blot analysis confirmed that the CD3+ alpha beta- T cells expressed TCR delta and gamma gene messages. In vivo treatment with anti-TCR alpha beta mAb, which suppressed most of the alpha beta T cells in the periphery and impaired resistance during the late stage of listerial infection, did not affect the host defense by day 6 after infection. A significantly increased number of gamma delta T cells was detected in the peritoneal cavity of the TCR alpha beta-suppressed rats on day 6 after infection. These results suggest that the early appearing gamma delta T cells may contribute to the host defense at a relatively early stage during listeriosis in rats.


T cell activation and thymic tolerance induction require different adhesion intensities of the CD8 co-receptor.

Activation of mature lymphocytes requires in addition to the TCR contact with the corresponding antigen the binding of the CD8 or CD4 co-receptors to MHC class I or class II proteins respectively. To investigate the contribution of the CD8-class I interaction to the elimination of autoreactive T cells during negative selection in the thymus we generated two types of transgenic mice. One set expressed a modified Kb molecule which contained a human HLA-A2 alpha 3 domain, thereby missing the binding residues for the murine CD8 molecules. The second set of mice expressed an anti-Kb specific TCR. Both lines were crossed and in the resulting double transgenic mice the development of Kb-reactive T cells was followed with an anti-clonotypic antibody. Surprisingly, efficient clonal deletion in the thymus was still observed, although the reduced CD8-class I adhesion abrogated effector functions in vivo and in vitro. These results imply that even T cells with intermediate affinity for self are negatively selected in the thymus despite the fact that they are not able to react against self antigens in the periphery. Thus a safety window is created which decreases the risk of autoaggression.


Delineation of chicken thymocytes by CD3-TCR complex, CD4 and CD8 antigen expression reveals phylogenically conserved and novel thymocyte subsets.

To further define the relationship between thymocyte subsets and their developmental sequence, multi-parameter flow cytometry was used to determine the distribution of the CD3-TCR complex and the accessory molecules CD4 and CD8 on chicken thymocytes. As in mammals, adult thymocytes could be subdivided into CD3-, CD3lo, and CD3hi staining populations. CD4 and CD8 distribution on such populations revealed the presence of CD3-CD4+CD8- and CD3-CD4-CD8+ thymocytes, putative precursors to CD4+CD8+ cells, detectable in the adult and at high frequency during ontogeny. Of particular interest was the existence of CD3lo expression on CD4+CD8- and CD4-CD8+, and in some instances, on CD4-CD8- thymocytes. Such phenotypes are not easily detectable in the mammalian thymus but were readily observed in both adult and embryonic chicken thymus from 16 days of embryogenesis. Further analysis of the TCR lineage of these CD3lo cells revealed that they were essentially all of the alpha beta TCR type. Mature CD3hi thymocytes were found within the CD4+CD8+ and CD4+CD8- and CD4-CD8+ subsets. Both alpha beta and gamma delta TCR lineage thymocytes were detected within all CD4- and CD8-defined subsets, thus identifying novel thymocyte subsets in the chicken thymus, namely alpha beta TCR+CD4-CD8- and gamma delta TCR+ CD4+CD8- cells. Hence, this analysis of chicken thymocytes, while confirming the phylogenically conserved nature of the thymus, has revealed novel T cell subsets, providing further insight into the complexity of mainstream thymocyte maturation pathways.


T cell-specific protein-DNA interactions occurring at the CD4 locus: identification of possible transcriptional control elements of the murine CD4 gene.

The cis-acting transcriptional control elements of the murine CD4 gene were investigated within 75 kb of chromatin associated with the CD4 locus. DNase I hypersensitive (DH) sites were identified in several T and non-T cell lines, and in freshly isolated thymocytes. A total of 22 DH sites were found, seven of which are present only in T cells expressing CD4 or CD8. The T cell-specific DH sites are located in four regions: (i) 5' of the first exon of CD4, (ii) in the first intron, (iii) near the second and third exons, and (iv) 3' of the CD4 gene. Some of these sites inversely correlate to the CD4 expression at defined stages of T cell development, suggesting a role for these sites in repression of this gene. The T cell-specific DH sites were subcloned and analyzed for protein-DNA interactions using the electrophoretic mobility shift assay. All T cell-specific DH sites analyzed appear to be a consequence of T cell-specific protein-DNA interactions. We have also identified the nuclear matrix attachment regions (MARs) and repetitive elements associated with the CD4 gene. Two nuclear MARs, separated by a region of highly repetitive DNA, are located 5' of the gene. Another region of highly repetitive DNA exists within the third intron. We discuss the implications of our results for the developmental regulation of CD4 expression.


Positive selection of V beta 2+ CD8+ T cells.

T cells bearing V beta 4, V beta 6, V beta 10, V beta 14, and V beta 17a are positively selected by MHC class I and/or class II molecules with poorly elucidated mechanisms. In this paper levels of V beta 2+ CD4+ and V beta 2+ CD8+ T cells from 33 inbred, five F1 hybrid, and 48 [(C58 x DBA/2)F1 x DBA/2] backcross mice have been examined. The results show that (i) V beta 2+ CD8+ T cells are positively selected by MHC class I H-2k molecules, (ii) this positive selection might be mediated by a non-H-2 ligand(s) in association with the Kk molecule, and (iii) inbred strains of mice, so far examined, do not have endogenous superantigens for deletion of V beta 2+ T cells.


Treatment of spinal deformity in myelomeningocele: a retrospective study in four hospitals.

Correction of spinal deformities in patients with myelomeningoceles (mmc) is notoriously complicated. To identify the deformity, frequency, gravity and complications of treatment a retrospective study was carried out on 61 patients from four hospitals. 45 patients had neurological defect above L3 and were wheelchair-bound. The indications for surgery were progressive disturbance in sitting balance, pain and pressure sores. Two types of spinal deformity were identified; scoliosis (often thoraco-lumbar or double major curves) and kyphosis (usually angular and lumbar). The mean age at operation was 12 years 8 months (2y 6m-19y 7m). Several operative procedures were used; posterior, anterior and circumferential fusion, and resection of the kyphosis. 52 solid fusions were achieved with variable correction at the cost of many complications such as excessive blood loss (2), post-operative pressure sores (15), failure of instrumentation (15), deep infection (11), and death following a CSF leak (1). 4 patients died from unrelated causes. Only 16 patients had no complications. The type and severity of scoliosis and kyphosis, operative technique, results and complications were correlated to identify the risks and define the optimal surgical technique for each type of spinal deformity in mmc.


Growth and the tethered cord syndrome.

We investigated the role of growth in relation to the tethered cord syndrome. By investigation of the growth curve in relation to the operation date we could not establish a period of increased growth preceding the operation date. Thus the operation date was not related to periods of increased length growth. Overstretching with microtraumata of the myelum may be a more important factor.


Factors affecting the school placement of children with spina bifida.

Integrating children with disabilities into mainstream schools has been an active policy in Britain since the 1981 Education Act. 26 children with spina bifida, 13 of whom were educated in mainstream schools, and 13 in special schools were assessed to clarify the relative importance of the following factors 1) IQ, 2) Mobility, 3) Hand function, 4) Bladder and bowel function, and 5) Behaviour. A marked difference was found between those attending mainstream and special schools. 11/13 of the former attained scores within the normal range as compared to only 2/13 of the latter. Neither mobility nor hand function alone were found to influence school placement and a marked correlation was found between the two. Whilst those educated in special schools had more marked problems, all children functioned poorly compared with the norms for able-bodied peers. Neither bladder nor bowel incontinence hindered attendance at mainstream school, but faecal soiling was considered the more serious problem. The frequency of behavioural problems showed a similar distribution amongst the two groups. Comments from parents highlighted their reservations about both special and mainstream schooling which indicates the policy for integration needs considerably more commitment from Government and Education Authorities in order to succeed.


Delayed amnesia and disorientation after electroconvulsive treatment.

Memory-related effects of electroconvulsive therapy (ECT) are known to appear immediately after the treatment. The case of a 39-year-old woman who underwent a course of ECT because of a recurrent major depressive disorder is described. After a symptom-free period of 48 hours, transient amnesia developed. Her condition appeared to be associated with the electroconvulsive therapy, thereby raising questions about its pathogenicity and management.


The addition of intravenous caffeine during an amobarbital interview.

Although the amobarbital interview is an effective means of temporarily relieving catatonic mutism, some catatonic patients simply fall asleep during an amobarbital interview. We are examining the feasibility of administering intravenous caffeine benzoate during an amobarbital interview to prevent patients from falling asleep. This paper describes an open trial of the administration of 500 mg caffeine benzoate during amobarbital interviews with ten patients. The procedure was well tolerated, but further studies are needed to determine whether or not caffeine is an advantage over amobarbital alone.


[Frontal lobe hypoactivity in schizophrenia: change in perspective].

Many attempts to isolate a dysfunctional site in the brain of schizophrenic patients have converged in a neuropathological conception of the disease based on frontal lobe hypoactivity. Recent data from studies using cytoarchitectony, computerized tomographic scans, cerebral regional blood flow, smooth pursuit eye movements and neuropsychological assessments are discussed. Current data on the hypofrontality hypothesis in schizophrenia seem to suggest an associationist rather than a localisationist perspective of the disorder.


Age, alcoholism and depression are associated with low levels of urinary melatonin.

Two normal control populations, separated by 8,000 miles and 24 degrees of latitude, had similar six-month mean values for overnight urinary melatonin concentrations. These values were significantly higher than six-month values for depressed subjects and abstinent alcoholic subjects, while the means for the two clinical populations were similar. Age and urinary melatonin concentration in the control and clinical populations were inversely related, but the slopes of the linear regression equations were ten times steeper for the control populations than for the clinical populations. Differences in age and sex distributions accounted for some of the differences in values between controls and the clinical populations, although controls still differed from the clinical populations, even after sex and age were factored out. The disparate slopes for age and melatonin concentrations may contribute to some of the conflicting findings of studies comparing populations of different ages. The total melatonin content in the samples from alcoholic subjects, but not the depressed subjects, was lower than that for controls. The difference in the urinary melatonin concentration between the controls and the two patient groups was not accounted for by difference in duration of urine collection period, hours of sleep or body weight.


Psychological factors, immunologic activation, and disease activity in rheumatoid arthritis.

The purpose of this study was to use structural equation modeling techniques to examine potential interrelationships among psychological factors, immunologic activation, and disease activity in rheumatoid arthritis (RA). The subjects were 80 male patients with a diagnosis of classic or definite RA. Measures included the Beck Depression Inventory, the Arthritis Helplessness Index, and the Arthritis Impact Measurement Scales (AIMS) pain score. Joint counts and immunophenotypic analyses of peripheral blood lymphocytes also were collected. Path analysis showed that percentage of HLA-DR+ cells in the peripheral blood and helplessness were related to join count. In addition, joint count had an effect upon depression. Depression had an effect upon pain, but there was no reciprocal effect of pain upon depression. This study describes a preliminary path model of interrelationships among psychological factors, immunologic activation, and disease activity in RA.


One-year evaluation of cognitive-behavioral intervention in osteoarthritis.

We compared a cognitive-behavior modification and a traditional education intervention for adults with osteoarthritis (OA). Forty OA patients were randomly assigned to one of two groups: cognitive-behavior modification or didactic lectures. During ten weekly sessions, the cognitive-behavior group learned methods for coping with pain and the disabilities associated with OA. The traditional education group experienced a series of lectures from health care professionals. Prior to the interventions and following 2, 6, and 12 months, patients in both groups were evaluated with a general Quality of Well-being (QWB) scale, the Arthritis Impact Measurement Scales (AIMS), the Beck Depression Inventory (BDI), and other measures. Although there were some differences between the two groups at 2-month follow-up, by the end of 1 year, physical and psychological functioning did not differ significantly between the two groups. In comparison to baseline, both groups demonstrated initial changes on QWB, depression, and the pain component of the AIMS. Improvements in depression remained through the 1-year follow-up. Multiple regression analysis demonstrated that the mobility and physical activity aspects of the AIMS were significant long-term predictors of outcome (1 year) for general quality-of-life measures. One-year outcomes for depression were significantly predicted from scores on social support and mobility measures from the AIMS. We conclude that cognitive-behavior modification and education produce similar effects on long-term physical and psychological functioning in OA patients.


Cardiovascular functional disorder in primary fibromyalgia: a noninvasive study in 17 young men.

Cardiovascular functional stability was studied in 17 young men (20-year-old conscripts) with the symptoms of primary fibromyalgia (PF). They were compared to 20 medical students of the same age. The subjects underwent an orthostatic test, deep breathing test, Valsalva maneuver, and a handgrip test. They were evaluated by an autoanamnestic questionnaire on vegetative symptoms and laboratory tests on blood chemistry. The heart rate of the PF group after 8 min of active standing was 32 +/- 15 beats/min greater than at supine rest. The corresponding figure for the controls was 23 +/- 7 beats/min (p = 0.001). Twelve conscripts with PF (71%) presented sympathicotonic cardiovascular reaction on the orthostatic test (p < 0.001). Four of these sympathicotonic conscripts and two other conscripts (total 35%) had an abnormal high index of dystonic symptoms (p = 0.01). The results suggest that young men with symptoms of PF have not only cardiovascular dystonic symptoms but also increased sympathetic nervous reactivity of the cardiovascular system.


A comparison of pain perceptions in women with fibromyalgia and rheumatoid arthritis: relationship to depression and pain extent.

Two studies were conducted to characterize the pain of fibromyalgia syndrome (FMS); to compare it to rheumatoid arthritis (RA) pain; and to examine the relationships between depression, pain extent, and pain description. Two methods of administering the McGill Pain Questionnaire (MPQ) were used. When the MPQ was administered in the standard manner, FMS pain could not be distinguished from RA pain. When participants were allowed to select as many words from an adapted MPQ as they wished, significant differences in word choice emerged. Depression and pain extent were major predictors of group differences in the evaluation of pain. However, depression scores contributed only 50% of the explanation for the differences in pain extent, with group membership contributing the other 50%. These findings suggest that the character and extent of pain in FMS are at least partially due to peripheral sensory components and not simply centrally controlled pain amplification secondary to depression.


Randomized, controlled trial of compression gloves in rheumatoid arthritis.

A randomized, controlled trial was conducted to determine efficacy of the Isotoner and the Futuro compression gloves in 39 patients with hand synovitis secondary to rheumatoid arthritis. After 7 days of nighttime treatment, both brands of gloves were found to decrease subjective symptoms of pain and stiffness (p < 0.05). In addition, swelling of the proximal interphalangeal joints decreased, while range of motion, rate of finger motion, and grip strength all increased (p < 0.05). Compression gloves should be used with caution in patients with bilateral carpal tunnel syndrome, because 12 of 13 such patients experienced worsening of their symptoms following one nighttime wearing of compression gloves. While both gloves were found to be efficacious in improving the signs and symptoms of hand synovitis, neither glove was found to be superior to the other. Patient preferences related to glove composition and fit may ultimately determine which glove to prescribe.


[Detection of HBV-DNA in peripheral blood mononuclear cells of anti-HIV-positive patients and its relation to other serological markers of HBV].

HBV infection has been investigated in 47 anti-human HIV positive patients in relation to a similar group of 33 anti-HIV negative patients. Serological HBV markers were found in 87% of anti-HIV positive patients. The difference in markers of viral replication (HBeAg, HBV-DNA) was not statistically significant between the two groups. It has been suggested that HBV infection of peripheral blood mononuclear cells could be a cofactor implicated in the development of immunodeficiency due to HIV. For this reason we have investigated the presence of HBV-DNA in peripheral blood mononuclear cells by in situ hybridization. Although its detection was more frequent in anti-HIV positive patients than in anti-HIV negative ones (p < 0.05), it was not related to clinical state of immunodeficiency. With regard to serological HBV markers, HBV-DNA was detected in peripheral blood mononuclear cells from antiHBc w/o antiHBs patients. This fact means the virus may persist in this cells after recovery and suggest they could serve as additional reservoirs of HBV. These cells, that contain the HBV genome, could be implicated in the perpetuation, reactivation of the infection and in its transmission.


[Microbiology and conservative surgery of serious infections of the diabetic foot].

Between June of 1987 and August 1988 we evaluated 31 diabetic patients hospitalized for severe foot infections to determine the etiologic agents, the value of the bacteriologic samples obtained, the benefits of conservative surgery and variable predictors of a major amputation. Sixteen patients suffered from necrosis, 16 osteomyelitis, 14 ulcers, 5 cellulitis, and/or abscesses and 22 had vascular compromise. Samples were taken from these infections excluding necrotic material. We isolate 76 microorganisms (2.4/pt), 57% Gram-positive cocci (predominantly S. aureus and enterococci), and 43% Gram-negative bacilli. Anaerobes were not isolated probably secondary to the exclusion of necrotic samples. There was high incidence of skin and soft tissue sampling (79%) bone (13/16) and surgical curettage (11/11). In 9 patients the correlation of soft tissue sampling and bone sampling was assessed with a positive correlation with respect to Gram-positive cocci. Twenty-one patients required conservative surgeries of the foot (9 underwent revascularization), 67% of which avoided a mayor amputation. However no significant variables predictive of a major amputation were detected in this study. In summary, the conservative surgery allowed to 2 out of 3 patients to preserve the foot.


[1st Spanish epidemic of plasmid resistance to 3d generation cephalosporins: the implication of SHV-2].

The first spanish outbreak of bacterial strains showing resistance to third generation cephalosporins and due to the presence of the extended spectrum beta-lactamase SHV-2 is reported. This outbreak was observed in Madrid during the years 1988-1990 and involved the San Carlos University Hospital with the same type of isolates at the Ramón y Cajal University Hospital. The screening for extended-spectrum beta-lactamases was performed by the double-disk synergy test. Analytical isoelectric focusing and susceptibility tests were performed in all the strains showing a presumptive extended-spectrum beta-lactamase. Fifty-nine strains belonging to four bacterial species (Klebsiella pneumoniae, 61%; Serratia marcescens, 31%; Klebsiella oxytoca, 5%, and Escherichia coli, 3%) showed a beta-lactamase of point isoelectric 7.6; the susceptibility tests demonstrated more resistance to cefotaxime and ceftriaxone than to ceftazidime and aztreonam. The biochemical, kinetic and isoelectrofocusing parameters demonstrated the presence of a SHV-2 enzyme. The blind application of NCCLS breakpoints would lead to false "susceptibility" results in over 40% of the cases.


[Human babesiosis. Study of vectors].

Babesiosis in an entity transmitted by tick bite presented in our medium producing high morbidity and mortality in immunodepressed patients. The prevalence of ticks infected with bovine Babesias was studied in a sample of 104 ticks collected from cattle for alimentation in the Sierra of the Autonomous Community of La Rioja. 3.84% of the ticks studied (3.3% of 89 Ixodes ricinus and 6.6% of 15 Dermacentor marginatus) presented Babesias in the hemolymph by Giemsa staining. A sizable degree of parasitization by bovine Babesia was found in the ticks of the medium studied. Given the possibility of parasitization by these parasites, babesiosis must be included in the differential diagnosis of the febrile hemolytic conditions seen in our environment.


[Hybridization using a digoxigenin-labeled probe for the detection of hepatitis delta virus].

The presence of hepatitis delta virus was investigated in liver biopsies by in situ cyto-hybridization with a probe labelled with digoxigenin. The techniques developed included extraction of plasmid DNA by lysis by alkali, electroelution, electrophoresis in agarose gel and digoxigenin labelling, and the application in liver tissue. Viral RNA was detected in 6 of the 10 patients, and the reactivity was exclusively restricted to the nucleolus of the hepatocytes. This method reveals as a sensitive and quick diagnostic procedure, which allows to study the intensity of the infection as well as the serological state of the patient.


[Myopathy and zidovudine].

The aim of this study was to evaluate the frequency of appearance of myopathy in a group of patients treated with zidovudine. A prospective study of 37 patients with positive serology for HIV treated over 180 days with zidovudine was carried out with evaluation of the clinical history, physical examination and analytical data. The initial mean value of creatine kinase of 76.4 U/l and 83.3 U/l following 6 months of treatment was not statistically significant. Of the 37 patients, 2 (5.4%) showed no variations in CK values, while in 4 (10.8%) there was a decrease and in 30 (81%) an increase. There was an elevation in 11 of the 15 patients (73%) who received doses equal to or lower than 90 g, 11 out of 13 (84.6%) of those who received between 90 and 145 g and 8 out of 8 (100%) of those having received doses higher than 145 g. This increase was minimum in 27 cases (92%) and important with final values of pathologic CK in 3 (8%). Two patients (5.4%) developed clinical manifestations. Not only the frequency and range of creatine kinase elevation but also the appearance of clinical manifestations in this study are lower than those found in the literature, probably because of the relation with the use of lower doses of zidovudine. These results do not demonstrate any relation with sex, age, risk group for the immunodeficiency status.


[IgG against A60 antigen and the tuberculin test in healthy individuals and tubercular patients].

Study of the relation between the antibodies against the A60 antigen and the tuberculin test. An indirect ELISA for detecting serum antibodies (IgG) against the antigen A60 and tuberculin test, has been applied to 20 patients with pulmonary tuberculosis, and 52 healthy persons without tuberculous history. For the all people (healthy and patients) both techniques have had almost identical results in 76.4%. In the healthy people the ELISA A60 and tuberculin test positive results were: 20.7% and 26.9%, respectively. For the patients group this results were: 85% and 80%. These results were statistically significant (p = 0.0001). In the healthy people the antibodies response against A60 antigen has a direct relationship with the results of the tuberculin test. The combined use of ELISA A60 and the tuberculin test improve their separate results.


[Endocarditis caused by Brucella melitensis on a mitral valve prosthesis presenting as an ischemic cerebrovascular accident].

A new case of endocarditis by Brucella melitensis on a mitral valve prosthesis in a 15 year old patient, whose first manifestation was an ischemic cerebrovascular accident is reported. The patient presented with daily fever only two months later. Medical treatment alone was not sufficient to avoid valvular failure and substitution of the prosthesis was required. The clinical manifestations and complications of this infrequent condition is discussed. Treatment, which often requires the combination of surgery and antibiotics administered over a prolonged period, is highly recommended.


[Fasciola hepatica infestation. Biopathology and new diagnostic and therapeutic aspects].

We present here 6 patients with Fasciola hepatica infection, all from rural origin, and with the risk factors of eating wild watercress. The more common symptoms were: fever (83%), abdominal pain (100%), weight loss (83%) and generalized myalgia and joint pain (67%). All patients presented with an absolute eosinophil count above 1,000 cell/mm3. The diagnosis was established in five cases by means of serologic techniques (haemagglutination) and with direct visualization of adult worms while surgery in one case. A CT abdominal scan was performed in five patients, revealing specific lesions of tissue infiltration in four of them. Praziquantel was used in four patients, achieving clinical cure in three cases. In two patients, bithionol was used, with clinical cure in both cases. We review also some newer diagnostic and therapeutic approaches to this parasitic disease.


[Nosocomial fungemia caused by Candida parapsilosis].

We review 27 episodes of nosocomial fungemia due to Candida parapsilosis over a 6 year period, compared to a control group of 27 episodes of nosocomial fungemia due to Candida albicans. During the study period, C. parapsilosis accounts for 23% of all yeast isolated from blood-cultures. Fungemia due to C. parapsilosis was more frequently seen in males (23/4). More than half of the cases (15/27) presented in the postoperative period. In 89% of cases the patients were under total parenteral nutrition and 81% had received broad-spectrum antibiotics. In 41% of cases, the source of the fungemia was unknown, and in another 41% of cases was related to an iv line infection. Direct attributable mortality to C. parapsilosis infection was 11%. When compared to the control group, nosocomial fungemia due to C. parapsilosis occurs in patient with more prolonged courses of total parenteral nutrition, and also was related with less frequent development of septic shock and lower attributable mortality.


[Features of Vibrio cholerae 0:1 El Tor, Inaba serotype, isolated during the cholera epidemic in Cartagena (Colombia)].

Cholera is an infectious transmissible disease characterized by the development of secretory diarrhea and that presents in epidemic and endemic forms. In Latin-America we are currently seen what could be the eight pandemic in cholera history, due to Vibrio cholerae 0:1 El Tor, Inaba serotype, infection. In the present preliminary study we analyze 300 patients with a clinical picture suggesting cholerae. In 250 cases, Vibrio cholerae 0:1 strains were isolated. The identification was made using mainly the following test and procedures: 1) growth in TCBS (saccharose fermentation), 2) Reactivity with sodium desoxycholate, 3) Oxidase-cytochrome test and 4) agglutination with polyvalent antisera. All isolated Vibrio cholerae strains 0:1 were sensitive to tetracycline, trimethoprim-sulfamethoxazole, norfloxacin, ciprofloxacin and gentamicin, but were resistant to ampicillin. This report summarizes the main features of Vibrio cholerae 0:1 El Tor, Inaba serotype, isolated in Colombian cholera epidemic.


[Prognostic value of plasma levels of fibronectin in septic shock].

The aim of the study was to assess possible changes in fibronectin serum levels in patients with septic shock and to analyze its usefulness as prognosis marker in this kind of shock. Fibronectin serum levels were determined in 20 patients with septic shock at 1, 3, 6, 12, 24 and 72 hours after the diagnosis was made. Serum level of fibronectin drops between 6 and 24 hours after shock starts, reaching its lower value around hour 12. The level recovered after 24 hours in those cases with good clinical evolution, but not in patients with bad outcomes. The analysis of fibronectin plasma level is a good prognostic marker for predicting survival in patients with septic shock.


[The suicide phenomenon and fermentative metabolic activity in strains of the Aeromonas group isolated from feces].

We study the "suicide" phenomena as well as metabolic pathways of mixed acids (methyl red test, MR) and butylene glycol (Voges-Proskauer, VP), in 107 strains belonging to mesophilic Aeromonas group, isolated from stools. The strains have been identified as A. hydrophila, 28 cases (26.1%), A. sobria 26 cases (24.3%) and A. caviae 53 cases (49.6%). All A. caviae strains behave homogeneously as F+, RM+ and VP-, independently of temperature (30 or 37 degrees C). A. hydrophila strains only showed their trend to "suicide" at 37 degrees C, being this behavior linked to RM test positivity. At 30 degrees C all strains were NS and RM-, keeping always positive the VP test (both temperatures). In A. sobria we have recorded changes in their behavior related to the temperature of incubation. At 37 degrees C, 57.7% were NS, whereas at 30 degrees C, 69.2% showed the same phenotype. The metabolic activity had remained stable, therefore F+ strains were VP and RM+, and NS strains were VP+ and RM-. It seems that FS is a phenotypic behavior of this bacterial group species and temperature-dependent, and also is related to a fermentative metabolic activity modulation of each of them.


[Multi-resistant strains of Salmonella typhi in Spain].

Most Salmonella typhi isolated in Spain are susceptible to antibiotics commonly used in its treatment as chloramphenicol, ampicillin and cotrimoxazole. Three multiresistant strains have been isolated from different patients the last two years. Two phage type M1, biotype xylose tetrationate + strains were isolated from blood of two patients in Bembibre (León). One phage type E1a biotype xylose + tetrationate reductase + strain was isolated from blood and faeces of one patient in Barcelona. All strains harboured a 79 Mdal plasmid responsible for multiresistance, chloramphenicol acetyl transferase production and conjugative.


[Fungemia caused by Rhodotorula mucilaginosa in relation to total parenteral nutrition].

Fungal infections are nowadays more common in clinical practice. The most frequently isolated fungi are Candida and Cryptococcus. Infection due to Rhodotorula mucilaginosa is very uncommon. We describe here our experience with R. mucilaginosa fungemia, with emphasis on total parenteral nutrition related episodes. A retrospective review identified 3 patients with R. mucilaginosa, and predisposing conditions, clinical features, treatment used and outcome were analyzed. The case definition includes the repeated isolation of R. mucilaginosa in several blood-cultures and/or the isolation of R. mucilaginosa in one single blood culture together with its isolation in any other site. Three patients were identified. In all of them there are some defects in immune response (skin anergy in two, immunosuppressive therapy in the remaining patient), had an iv line placed, under antibiotic therapy and total parenteral nutrition. All factors could have been related to the development of R. mucilaginosa infection. Although its pathogenic role is controversial, in two or our patients R. mucilaginosa infections correlates well with clinical signs and symptoms of invasive infections (fever, hemodynamic changes). The treatment is still not clear.


Toxic colitis: diagnosis and management.

Toxic colitis, a serious complication of ulcerative colitis and Crohn's disease, may be life threatening. Early diagnosis and ensuing intensive medical therapy may control the disease process. Lack of rapid response to medical therapy necessitates surgical intervention. Subtotal colectomy and ileostomy is the operative procedure of choice. This allows resolution of the disease process and does not destroy the options for restorative operation at a later date.


Children with ostomies: parents helping parents.

Thousands of ostomies are performed on children every year to treat a variety of acquired conditions and congenital anomalies. The parents of children with ostomies are faced with the challenge of successfully living with and managing their child's ostomy. These families need practical information and support, both from the professional community and from parents who have shared the responsibility of a child with an ostomy. A parental support network has been developed throughout the country to address some of the needs of these families. This article provides current information about the status of these networks: what they have to offer and how they can be accessed. These groups, which continue to evolve, demonstrate a trend within this unique population. The parents of a child with an ostomy no longer need to feel alone in their experience.


Self-image changes with time in the cancer patient with a colostomy after operation.

Persons undergoing colostomy surgery face body mutilation and some loss of body function, which in turn causes their concept of self to change. Although nurses use physical and behavioral indicators as bases for assessment, planning, and evaluation of nursing intervention, only minimal empiric data is available on the physical and behavioral indicators of self-concept changes (e.g., lack of participation in self-care, depression, anxiety, fear of social rejection) among these patients. This study is a beginning in the description of the self-concept changes with time of the patient with a colostomy. The purpose of this study was twofold: (1) to begin the description of the postoperative behavioral indicators of cancer patients with colostomies according to Erikson's stages of trust and autonomy at 4 and 12 weeks after operation; and (2) to measure several indexes of psychosocial discomfort anticipated by patients before colostomy operations and them measurements with measurements of psychosocial discomfort at 4 and 12 weeks after operation. The study design incorporated three serial assessments. Each consenting subject was interviewed once before the operation and twice after (at 4 and 12 weeks). The study sample consisted of 12 subjects who had colostomy operations for cancer. Ages ranged from 41 to 74 years, with a mean age of 59.4 years. Results show an increase in trust, from a mean of 203.6 at 4 weeks to a mean of 221.7 at 12 weeks. Autonomy scores decreased, from 146.2 at 4 weeks to 143.9 at 12 weeks. Psychosocial discomfort decreased from 25.7 before to 22.1 4 weeks after and 8.0 12 weeks for operation.(ABSTRACT TRUNCATED AT 250 WORDS)


[Stationary kinetics of the function of multienzyme membrane sensors with electrochemical enzyme regeneration].

A theoretical analysis of the functioning of membrane biosensors based on consecutive polyenzymatic transformations of the substrate and detectable by indicator electrodes with electrochemical regeneration of the enzyme active sites, has been carried out. Correlations between the substrate concentration, diffusion-catalytic characteristics of the coating components, and rate of the indicator reaction on the one hand, and the level of the steady-state response of the polyenzymatic biosensors, on the other, have been determined for relatively low values of the polyenzymatic layer thickness. Various regimens of functioning of bienzymatic electrodes have been considered.


[Effective diameter of pores in rat liver mitochondria inner membrane and selectivity of transport of monovalent cations with a submicromolar concentration of Ca2+ ions or A23187 and EDTA].

Studies of swelling of rat liver mitochondria in isoosmotic solutions of nonelectrolytes in the presence of respiration inhibitors revealed that submicromolar concentrations of Ca2+ increase the diameter of pores in the inner mitochondrial membrane--from 5.5-6.0 A (10(-8) M Ca2+) up to 7.5 A (3 x 10(-7) M Ca2+) and 8.0-8.5 A (6 x 10(-7) M Ca2+); these increases are prevented by cyclosporin A. The inner mitochondrial membrane with an effective pore diameter of 7.5 A is readily permeable for potassium but not for sodium ions, although with an increase in the effective pore diameter up to 8.0-8.5 A the selectivity of the K(+)-Na+ channel decreases. A conclusion is drawn that in the presence of submicromolar concentrations of Ca2+ the conductivity of the cyclosporin-sensitive pore for monovalent cations increases in the following order: K > Na > Li.


[Detection of left-helical segments in eukaryotic DNA].

The method of DNA binding to nitrocellulose filters was applied to DNA isolated from mouse liver and Ehrlich ascite carcinoma (EAC), calf thymus, and lymphocytes from patients with chronic lymphoid leukemia. In those and phage PM2 DNA the increase in the DNA binding to the filters with a rise in NaCl concentration from 0.5 up to 4.5 M was sigmoidal being suggestive of a conformational transition. No such activity was found in the case of phage lambda or single-stranded DNA. The binding decreased dramatically after mild cleavage of DNA with DNAase I or treatment with phospholipase C or Eco RI and Hin PI restrictases. Incubation of DNA with ethidium bromide led to decrease in the amount of bound DNA. This effect was enhanced with a rise in the dye concentration. The isotherms of ethidium bromide binding to eukaryotic DNA obtained in Scatchard plots by optic titration had a component with a positive slope at low values of r. Bivalent ions (Mg2+, Zn2+) shifting the equilibrium towards the Z-form increased the proportion of macromolecules retained on the filters at NaCl concentrations of 1-3 M. Local changes in the helix conformation were studied with the help of chemical probes: diethylpyrocarbonate (guanine Z-DNA) and osmium-pyridine reagent (pyrimidines of boundary B-Z sites). These probes incorporation into samples of liver DNA, EAC, and lymphocytes resulted in chemical modification of all these samples. Modification of DNA by osmium-pyridine reagent led to inhibition of subsequent restriction by Eco RI restrictase. The data obtained are suggestive of the presence of Z-regions in the B-helix of eukaryotic DNA. A topological model of Z-site stabilization in small superhelical loops of DNA fixed by protein or lipoprotein molecules is proposed.


Pressure ulcers: developing a program of care.

The treatment of pressure ulcers has evolved from dry to moist healing techniques. Institutions must therefore develop a method to advance their clinical practices. Such a major change requires a systematic implementation of a comprehensive wound management program. The steps necessary in this program development include review of the current literature, review of current practice, standardization of treatment, assessment of product availability, standardization of documentation, in-service training of staff, and evaluation of program success.