Photonic emitter manipulation to sample nanoscale topography

We demonstrate that photonic emitter manipulation can be used to image the nanoscale topography of a fluorescently labeled layer in confocal imaging. We exploit the fact that a metallic probe manipulates a fluorophore's photonic environment, and thereby its fluorescent lifetime, in a strongly distance-dependent manner. To image surface topography, a metallic probe that is not in contact with the surface is rasterscanned over a fluorescently labeled sample. The axial position of the probe is kept constant. At each lateral probe position, the fluorescence decay is recorded and analyzed to obtain probe - sample distances and hence, the topography of the sample. We present images resolving a microfabricated step of 14 nm in topography, with the probe positioned at different axial positions.

Predictors of nonresponse to fluid restriction in hyponatraemia due to the syndrome of inappropriate antidiuresis

BACKGROUND

Fluid restriction (FR), the first-line treatment for hyponatraemia due to the syndrome of inappropriate antidiuresis (SIAD), often does not lead to successful correction of hyponatraemia. Therefore, predictive markers of treatment response are desirable. We evaluated routinely measured serum (s) and urine (u) parameters, s-copeptin and s-mid-regional pro-atrial natriuretic peptide (s-MR-proANP), as possible predictors of FR response.

METHODS

In this prospective observational study, we included patients with profound hyponatraemia (s-sodium <125 mmol L^-1 ) due to SIAD. Patients were classified as FR responders (increase in s-sodium concentration of >3 mmol L^-1 within 24 h) or nonresponders (increase of ≤3 mmol L^-1 within 24 h). Initial laboratory parameters were compared between groups with logistic regression analysis.

RESULTS

Of 106 SIAD patients analysed, 82 underwent treatment with FR; 48 (59%) patients showed a successful response to FR and 34 (41%) were considered nonresponders. High levels of u-sodium and u-osmolality were significantly associated with nonresponse to FR [odds ratio (OR) 15.0, 95% confidence interval (CI) 2.4-95.8, P = 0.004 and OR 34.8, 95% CI 1.2-1038.8, P = 0.041, respectively). The association of u-sodium and nonresponse remained significant also after adjustment for diuretic use. Lower levels of s-MR-proANP were associated with nonresponse (OR 0.03, 95% CI 0.003-0.3, P = 0.004), whereas s-copeptin was not significantly associated with response to FR.

CONCLUSION

Easily measured laboratory parameters, especially u-sodium, correlate with therapeutic response and identify patients most likely to fail to respond to FR. Measurement of these parameters may facilitate early treatment choice in patients with SIAD.

Microcantilever based distance control between a probe and a surface

We demonstrate a method to control the distance between a custom probe and a sample on a μm to nm scale. The method relies on the closed-loop feedback on the angular deflection of an in-contact AFM microcantilever. High performance in stability and accuracy is achieved in this method by taking advantage of the small mechanical feedback path between surface and probe. We describe how internal error sources that find their origin in the microcantilever and feedback can be minimized to achieve an accurate and precise control up to 3 nm. In particular, we investigated how hysteresis effects in the feedback caused by friction forces between tip and substrate can be minimized. By applying a short calibration procedure, distance control from contact to several micrometers probe-sample distance can be obtained with an absolute nanometer-scale accuracy. The method presented is compatible with any probe that can be fixed on a microcantilever chip and can be easily built into existing AFM systems.

[Drug-drug interactions with HIV treatments]

We develop a differential diagnosis and diagnostic approach to a possible drug-drug interaction between a cART based on boosted atazanavir and newly given drugs. History taking should not only encompass prescribed but also over-the-counter medication. Exchange of information between attending physicians as to therapeutic changes, documented side effects and adherence, therapeutic drug monitoring of cART and evaluation by pharmacologist in complex situations are the diagnostic tools at hand.

Method to deterministically study photonic nanostructures in different experimental instruments

We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the nanostructure is made during the fabrication of the structure. These maps are made using a series of micrographs with successively decreasing magnifications. The graphs reveal intrinsic and characteristic geometric features that can subsequently be used in different setups to act as markers. As an illustration, we probe surface cavities with radii of 65 nm on a silica opal photonic crystal with various setups: a focused ion beam workstation; a scanning electron microscope (SEM); a wide field optical microscope and a confocal microscope. We use cross-correlation techniques to recover a small area imaged with the SEM in a large area photographed with the optical microscope, which provides a possible avenue to automatic searching. We show how both structural and optical reflectivity data can be obtained from one and the same nanostructure. Since our approach does not use artificial grids or markers, it is of particular interest for samples whose structure is not known a priori, like samples created solely by self-assembly. In addition, our method is not restricted to conducting samples.

Combining decision support and image processing: a PROforma model

This paper addresses two important problems in medical image interpretation:(1) integration of numeric and symbolic information, (2) access to external sources of medical knowledge. We have developed a prototype in which image processing algorithms are combined with symbolic representations for reasoning, decision making and task management in an integrated, platform-independent system for the differential diagnosis of abnormalities in mammograms. The prototype is based on PROforma, a generic technology for building decision support systems based on clinical guidelines. The PROforma language defines a set of tasks, one of which, the enquiry, is used as means of interaction with the outside world. However, the current enquiry model has proved to be too limited for our purposes. In this paper we outline a more general model, which can be used as an interface between symbolic functions and image or other signal data.

Thymus medulla consisting of epithelial islets each derived from a single progenitor

The thymus is organized into medullary and cortical zones that support distinct stages of T-cell development. The formation of medulla and cortex compartments is thought to occur through invagination of an endodermal epithelial sheet into an ectodermal one at the third pharyngeal pouch and cleft, respectively. Epithelial stem/progenitor cells have been proposed to be involved in thymus development, but evidence for their existence has been elusive. We have constructed chimaeric mice by injecting embryonic stem (ES) cells into blastocysts using ES cells and blastocysts differing in their major histocompatibility complex (MHC) type. Here we show that the MHC class-II-positive medullary epithelium in these chimaeras is composed of cell clusters, most of which derive from either embryonic stem cell or blastocyst, but not mixed, origin. Thus, the medulla comprises individual epithelial 'islets' each arising from a single progenitor. One thymic lobe has about 300 medullary areas that originate from as few as 900 progenitors. Islet formation can be recapitulated after implantation of 'reaggregated fetal thymic organs' into mice, which shows that medullary 'stem' cells retain their potential until at least day 16.5 in fetal development. Thus, medulla-cortex compartmentalization is established by formation of medullary islets from single progenitors.

Low dose streptozotocin-induced diabetes in rat insulin promoter-mCD80-transgenic mice is T cell autoantigen-specific and CD28 dependent

Although transgenic mice expressing murine B7-1 (mCD80) on their pancreatic beta cells under the rat insulin-1 promoter (RIP-mCD80(+) mice) rarely develop spontaneous beta cell destruction and diabetes, we have previously reported the transgene-dependent induction of profound insulitis and lethal diabetes following multiple low dose injections of the beta cell toxin streptozotocin (MLDS) in RIP-mCD80(+) mice. Here, we have further characterized this MLDS-induced diabetes model using the RIP-mCD80(+) mice and now demonstrate that disease is critically dependent on T cell signaling via CD28. Thus, although naive RIP-mCD80(+) and nontransgenic littermates have comparable gross beta cell mass, and immediately following MLDS induction the mice display similar degrees of insulitis and decrements in the beta cell mass, only transgenic mice continued to destroy their beta cells and develop insulin-dependent diabetes mellitus. Strikingly, MLDS-induced diabetes was completely prevented in CD28-deficient mice (RIP-mCD80(+)CD28(-/-)) due to abrogation of leukocytes infiltrating their pancreatic islets. We further characterized MLDS-induced diabetes in the RIP-mCD80(+) mice by demonstrating that the MLDS-induced lymphocytic islet infiltrate contained a substantial frequency of autoantigen-specific, IFN-gamma-secreting, CD8(+) T cells. We conclude that MLDS-induced beta cell destruction and subsequent insulin-dependent diabetes mellitus in RIP-mCD80(+) mice is T cell-mediated as it involves both Ag-specific recognition of self-target molecules in the inflamed pancreatic islet (signal 1) and is CD28 costimulation dependent (signal 2).

Toddler drowning in domestic swimming pools

AIMS

To identify how toddlers who drowned gained access to private swimming pools; to recommend preventive strategies to reduce the incidence of toddler drowning and near drowning.

METHOD

The study reviewed critically all completed investigations into the drowning deaths of toddlers aged 1-4 years reported to the state coroner (n=33) as a result of unintentional submersion incidents in domestic swimming pools in Victoria, Australia, from 1 January 1992 to 31 December 1997.

RESULTS

There was a predominance of 1 year olds, and boys. Forty six per cent of the children drowned in the three summer months. The majority of pools were in-ground; most were located on the child's home property. Over half the pools lacked fencing of any kind; of those that did have fences, only three appear to have met Australian standards.

CONCLUSIONS

More than half of the children studied drowned in unfenced pools and spas. In not one case did a child gain unaided access to a pool fitted with a fully functional gate and fence that met the Australian standard. Where children gained access to fenced pools, the majority did so via faulty or inadequate gates, or through gates that were propped open. This finding highlights the need for pool owners to install Australian standard approved fences and gates, and to maintain existing fences and gates regularly. Door locks and supervision were inadequate primary prevention strategies.

Quantification of microglial late reaction to stereotactic irradiation of the rat brain using computer-aided image analysis

The role of microglial cells in the late delayed reaction following radiotherapy of brain tumors has not been elucidated. To investigate the late delayed response of microglial cells to radiation, we stereotactically irradiated spherical treatment volumes in the right frontal lobe of rat brains. Doses of 20, 30, 40, and 50 Gy were used in combination with two different collimators. The response of microglial cells at 10 and 19 months after irradiation was determined with Anti-CD 11 b/c (Ox 42) as an immunohistochemical marker. For evaluation of immunostaining, we developed a method using computer-aided image analysis in which the ratio of the area of stained cells to that of nonstained brain tissue is calculated. In addition, quantification of Ox-42+ cells per microscopic field was performed. Animals treated with 30 Gy or more had significantly increased total areas of staining at both time points studied. In contrast, the number of stained cells at 10 months increased significantly only in animals treated with 30 or 40 Gy. Likewise, at 19 months, this number increased significantly only in animals treated with 40 Gy or more. These results indicate that computer-aided determination of the area of stained cells is more sensitive than the counting of stained cells. We have demonstrated that microglial cells respond to stereotactic irradiation in a dose-dependent fashion. The image analysis we employed for this purpose is a systematic method to evaluate immunohistochemical staining.

Regional tumor oxygenation and measurement of dynamic changes

We recently described a novel approach to measuring regional tumor oxygen tension using (19)F pulse burst saturation recovery (PBSR) nuclear magnetic resonance (NMR) echo planar imaging (EPI) relaxometry of hexafluorobenzene. We now compare oxygen tension measurements in a group of size-matched R3327-AT1 Dunning prostate rat tumors made using this new method with those using a traditional polarographic method: the Eppendorf histograph. Similar oxygen tension distributions were found using the two methods, and both techniques showed that tumors with volume greater than 3.5 cm(3) were significantly (P < 0.0001) less well oxygenated than smaller tumors (volume less than 2 cm(3)). Using the (19)F EPI approach, we also examined the response to respiratory challenge. Increasing the concentration of inspired oxygen from 33% to 100% O(2) produced a significant increase (P < 0.0001) in tumor oxygenation for a group of small tumors. In contrast, no change was observed in the mean pO(2) for a group of large tumors. Consideration of individual tumor regions irrespective of tumor size showed a strong correlation between the maximum pO(2) observed when breathing 100% O(2) compared with mean baseline pO(2). These results further demonstrate the usefulness of (19)F EPI to assess changes in regional tumor oxygenation.

Cutting edge: anti-CD1 monoclonal antibody treatment reverses the production patterns of TGF-beta 2 and Th1 cytokines and ameliorates listeriosis in mice

Protection against intracellular bacteria by T cells is regulated by Ag-presenting molecules, which comprise classical MHC class I molecules, MHC class II molecules, and nonclassical MHC class Ib molecules. The role of CD1 molecules, which are structurally similar to classical MHC class I gene products, but less polymorphic, is not understood so far. We show that CD1 surface expression increased on APC in Listeria-infected mice. The in vivo treatment with anti-CD1 mAb reduced TGF-beta 2 levels and concomitantly increased secretion of the proinflammatory cytokine TNF, the Th1 cell promoting cytokine IL-12, and the Th1 cell cytokine IFN-gamma at the onset of listerial infection. These findings point to a regulatory role of CD1-reactive cells in the immune response against listeriosis.

Bioavailability of soilborne lead in adults, by stable isotope dilution

Using stable isotope dilution, we determined the bioavailability of soilborne lead (Pb) in human adult volunteers. Soil from a residential yard at a mining-impacted federal Superfund site that had negligible amounts of other priority pollutants was dried and screened through a 25-micron mesh sieve. The < 250-micron fraction, which likely represents that ingested via hand-to-mouth activity, was then sterilized by exposure to radiation. Ten replicate samples yielded a mean (SD) soil Pb concentration of 2924 +/- 36 ppm, and a mean 206Pb/207Pb ratio of 1.1083 +/- 0.0002, indicating remarkable soil homogeneity. Six adults with 206Pb/207Pb ratios of > 1.190 were admitted to the clinical research center and fasted overnight prior to dosing with 250 micrograms Pb/70 kg bw (i.e., 85.5 mg soil/70 kg) in a gelatin capsule. Blood for Pb and 206Pb/207Pb ratios was obtained at 14 time points through 30 hr. Results of the isotopic analyses from these subjects indicate that on average 26.2% +/- 8.1 of the administered dose was absorbed. Six additional subjects were subsequently studied but ingested soil immediately after a standardized breakfast. Bioavailability in this group was only 2.52% +/- 1.7. Collectively, this study provides the first experimental estimates of soil Pb absorption in humans, and should allow for more precise estimates of health risks due to Pb-contaminated soil.

Lethal tuberculosis in interleukin-6-deficient mutant mice

Tuberculosis is a chronic infectious disease which causes major health problems globally. Acquired resistance is mediated by T lymphocytes and executed by activated macrophages. In vitro studies have emphasized the importance of macrophage activation for mycobacterial growth inhibition. In vivo, the protective host response is focused on granulomatous lesions in which Mycobacterium tuberculosis is contained. A cellular immune response of the T helper 1 (Th1) type is considered central for control of tuberculosis. Using interleukin-6 (IL-6)-deficient mice, we here demonstrate a crucial role of this pluripotent cytokine in protection against M. tuberculosis but not against Mycobacterium bovis BCG. Infection with M. tuberculosis was lethal for the IL-6-deficient mice at inocula that were still controlled by IL-6-competent mice. Spleen cells from M. tuberculosis-infected IL-6-/- mouse mutants produced elevated levels of IL-4 and reduced levels of gamma interferon compared to the control levels. Cytofluorometric analyses of spleen cells from M. tuberculosis-infected mice revealed more-profound alterations in T-cell ratios in IL-6-/- mice than in control mice. We assume that IL-6 contributes to host resistance by its proinflammatory activity and by its influence on cytokine secretion.

IL-4 neutralization or TNF-alpha treatment ameliorate disease by an intracellular pathogen in IFN-gamma receptor-deficient mice

Successful control of infectious disease depends on aquisition of an appropriate protective immune response. IFN-gamma, first produced by NK cells and then by Th1 cells, is central to acquired resistance against intracellular bacteria, including Listeria monocytogenes. In contrast, IL-4 is not generated to a measurable degree. Here we show that IL-4 is produced during listeriosis by IFN-gamma receptor gene disruption (IFN-gammaR(-/-)) mutant mice. Production of TNF was diminished, whereas IL-12 production was virtually unchanged in these mutants. Neutralization of IL-4 with anti-IL-4 mAb, as well as TNF-alpha reconstitution with rTNF-alpha, ameliorated listeriosis. These findings demonstrate the detrimental effects of IL-4 in listeriosis independent of IFN-gamma down-regulation and document the far-reaching consequences of a single cytokine deficiency on other cytokines. In cases where the primary gene defect cannot be restored, precise identification of secondary effects will promote rational immunotherapy based on neutralization or reconstitution of secondary immune deviations.

IL-4 neutralization or TNF-alpha treatment ameliorate disease by an intracellular pathogen in IFN-gamma receptor-deficient mice

Successful control of infectious disease depends on aquisition of an appropriate protective immune response. IFN-gamma, first produced by NK cells and then by Th1 cells, is central to acquired resistance against intracellular bacteria, including Listeria monocytogenes. In contrast, IL-4 is not generated to a measurable degree. Here we show that IL-4 is produced during listeriosis by IFN-gamma receptor gene disruption (IFN-gammaR(-/-)) mutant mice. Production of TNF was diminished, whereas IL-12 production was virtually unchanged in these mutants. Neutralization of IL-4 with anti-IL-4 mAb, as well as TNF-alpha reconstitution with rTNF-alpha, ameliorated listeriosis. These findings demonstrate the detrimental effects of IL-4 in listeriosis independent of IFN-gamma down-regulation and document the far-reaching consequences of a single cytokine deficiency on other cytokines. In cases where the primary gene defect cannot be restored, precise identification of secondary effects will promote rational immunotherapy based on neutralization or reconstitution of secondary immune deviations.

Control of natural killer cell-mediated innate resistance against the intracellular pathogen Listeria monocytogenes by gamma/delta T lymphocytes

Listeria monocytogenes is an intracellular bacterium which causes an acute infectious disease in mice. Initial host resistance depends on innate immunity mediated primarily by natural killer (NK) cells followed by specific alpha/beta T cells, which are central to acquired specific immunity. Gamma/delta T lymphocytes seem to provide a link between the innate and the specific immune response. All these lymphocyte populations produce gamma interferon (IFN-gamma), which, because of its macrophage-activating potential, is central to antibacterial protection. IFN-gamma from NK cells not only contributes to early host resistance but also promotes development of protective T-cell responses of helper T type 1 (Th1) type. Here, we show that innate resistance and early IFN-gamma production in listeriosis are markedly impaired in T-cell receptor (TCR)-delta-/- but not TCR-beta-/- gene disruption mutant mice. By two-color cytofluorimetry, we demonstrate that NK cells rather than gamma/delta T lymphocytes are the major cellular source of IFN-gamma in immunocompetent mice and that IFN-gamma production by NK cells is impaired in the TCR-delta-/- mutants. Probably, reduced tumor necrosis factor production in listeria-infected TCR-delta-/- mutants contributed to impaired NK cell activation. Our data reveal a novel function of gamma/delta T cells as regulators of innate resistance against sublethal infection with an intracellular pathogen.

Protective role of gamma/delta T cells and alpha/beta T cells in tuberculosis

Tuberculosis is a chronic infectious disease which causes major health problems globally. Although acquired resistance crucially depends on alpha/beta lymphocytes, circumstantial evidence suggests that, in addition, gamma/delta T lymphocytes contribute to protection against tuberculosis. We have studied Mycobacterium tuberculosis infection in TcR-delta-/- or TcR-beta-/- gene deletion mutants which completely lack gamma/delta T cells or alpha/beta T cells, respectively. Low inocula of M. tuberculosis led to death of TcR-beta-/- mice and transient disease exacerbation in TcR-delta-/- mutants. Infection with higher inocula caused rapid death of TcR-delta-/- mice. The development of and bacterial containment in granulomatous lesions was markedly impaired in TcR-beta-/-, and less severely affected in TcR-delta-/- mutants. Mycobacteria-induced IFN-gamma production by spleen cells in vitro was almost abolished in TcR-beta-/- and virtually unaffected in TcR-delta-/- mice. Our data confirm the crucial role of alpha/beta T cells in protection against established tuberculosis and formally prove a protective role of gamma/delta T cells in early tuberculosis.

Control of thymus-independent intestinal intraepithelial lymphocytes by beta 2-microglobulin

Murine intestinal intraepithelial lymphocytes (i-IEL) comprise thymus-dependent cells such as T cell receptor (TcR) alpha/beta CD8 alpha/beta+ i-IEL, as well as thymus-independent ones such as TcR alpha/beta CD8 alpha/alpha+ and TcR gamma/delta CD8 alpha/alpha+ i-IEL. Whilst the development of the CD8 alpha/beta expressing i-IEL is strictly contingent on major histocompatibility complex (MHC) class I surface expression, that of CD8 alpha/alpha i-IEL appears largely MHC class I independent. We have used beta 2-microglobulin (beta 2m)-/- mutant mice lacking surface-expressed MHC class I and TcR alpha/beta CD8 alpha/beta+ i-IEL to analyze the potential impact of MHC class I on regional activation of thymus-independent i-IEL. To analyze the role of TcR gamma/delta i-IEL in regional cell interactions, these mice were treated with the anti-TcR gamma/delta mAb, GL3. Whilst numbers of TcR alpha/beta CD8 alpha/alpha i-IEL were markedly reduced in beta 2m-/- mice, those of TcR gamma/delta i-IEL were elevated. Administration of GL3 in vivo caused TcR down-modulation and functional inactivation of TcR gamma/delta i-IEL in beta 2m+/- mice. In contrast, TcR expression and functional activities of TcR gamma/delta i-IEL from beta 2m-/- mice were not impaired by GL3 treatment. The TcR alpha/beta CD8 beta- i-IEL from beta 2m-/- mice were expanded and functionally activated as a consequence of TcR gamma/delta engagement. The TcR gamma/delta i-IEL and TcR alpha/beta CD8 alpha/alpha+ i-IEL from athymic nu/nu mice which express MHC class I, but lack TcR alpha/beta CD8 alpha/beta+ i-IEL, responded to TcR gamma/delta engagement as those from the beta 2m+/- controls. In addition, the TcR gamma/delta i-IEL from TcR beta-/- and TCR beta+/- mutants were equally affected by GL3. We conclude that the absence of beta 2m renders TcR gamma/delta i-IEL resistant to TcR-mediated inactivation and promotes activation of TcR alpha/beta CD8 beta- i-IEL. The activation of TcR gamma/delta i-IEL seems to be directly controlled by beta 2m/MHC class I expression and independent from TcR alpha/beta CD8 beta+ i-IEL. Regulation of self-reactive thymus-independent i-IEL through beta 2m/ MHC class I may contribute to control of autoreactive immune responses in the intestine.

The role of caregiver social networks in Alzheimer's disease

Although the theoretical importance of social networks in alleviating caregivers' mental distress when a family member has Alzheimer's disease is well-established, empirical support has been less definitive. For 58 patient-spouse caregiver dyads, we used an array of network variables within a causal model of stress. We found that: caregiver networks are associated with severity of illness but not duration; increased illness severity was associated with network members assuming new roles; social networks had indirect effects but no direct or buffering effects on caregiver psychological distress; religious attendance had direct and indirect effects on caregiver psychological distress. These findings point to the important, but complex, role that social networks play in affecting caregivers. However, because of its cross-sectional nature and the relatively small sample size, this study will require replication on larger samples using longitudinal analyses.

Baseline silent cerebral infarction in the Asymptomatic Carotid Atherosclerosis Study

BACKGROUND AND PURPOSE

In a group of patients with high-grade asymptomatic carotid artery stenosis, we prospectively determined the prevalence and radiological characteristics of clinically asymptomatic brain infarction evident on computed tomography. Risk factors and extent of carotid disease were also determined.

METHODS

Patients randomized into the Asymptomatic Carotid Atherosclerosis Study (ACAS) underwent a neurological history, a detailed stroke/transient ischemic attack questionnaire, and a detailed neurological examination. Computed tomography scans were examined by standardized criteria developed as part of a quality-control program supervised by a neuroradiologist. The presence, location, and size of all cerebral infarctions evident by computed tomography were determined.

RESULTS

Among 1132 patients, 848 had no history of stroke or transient ischemic attack. One hundred twenty-six patients (15%) had a silent infarct; 95 (11%) had one, 24 (3%) had two, and 7 (1%) had three or more infarcts. The infarct size was small and deep for 117 patients (72%), less than one-half lobe for 45 (28%), and one-half to less than one lobe for 1 (0.5%). The silent infarcts were evenly distributed ipsilaterally and contralaterally to the study artery but were significantly more frequent in the right hemisphere (P < .05). Factors associated with silent infarction were abnormal gait (P < .001), abnormal deep tendon reflexes or plantar responses (P = .038), but not degree of carotid stenosis. Silent infarction was less frequent among this totally asymptomatic cohort (15%) compared with those with transient ischemic attacks (34/139, 25%; P < .001).

CONCLUSIONS

Silent infarction in the setting of asymptomatic carotid stenosis is not uncommon, but silent infarctions are rarely sizable. The clinical significance of silent cerebral infarction in patients with asymptomatic carotid artery stenosis has yet to be established.

Crosstalk between alpha/beta T cells and gamma/delta T cells in vivo: activation of alpha/beta T-cell responses after gamma/delta T-cell modulation with the monoclonal antibody GL3

Although gamma/delta T cells express numerous in vitro functions similar to alpha/beta T cells, little is known about their biological functioning in vivo. Furthermore, it is unclear whether alpha/beta T cells and gamma/delta T cells act independently or in a coordinated way. In the present study, gamma/delta T cells were modulated in vivo by i.p. injection of the anti-gamma/delta T-cell receptor (TCR) monoclonal antibody GL3. GL3 administration caused disappearance of the gamma/delta TCR in spleen and lymph node cells and the gamma/delta TCR was reexpressed after in vitro cultivation for a few days. When cultured in vitro for 4 days, in the absence of foreign antigens, spleen and lymph node alpha/beta T cells from GL3-modulated mice showed vigorous proliferative responses. CD4 T lymphocytes from GL3-modulated mice produced interleukin 2, and CD8 T cells developed into cytolytic T lymphocytes in vitro capable of lysing syngeneic and allogeneic targets. Treatment with heat-inactivated GL3 or with normal hamster immunoglobulin did not cause any of these effects. These findings suggest that the anti-gamma/delta TCR monoclonal antibody GL3 modulates gamma/delta T cells in vivo and that this modulation has profound effects on alpha/beta T-cell reactivity. Hence, the data suggest a role for gamma/delta T cells in the regulation of alpha/beta T-cell activation in vivo.

Blood pressure during the first minutes of focal cerebral ischemia

STUDY OBJECTIVE

To determine whether blood pressure declines spontaneously during the first minutes and hours of focal cerebral ischemia.

DESIGN

Multiple blood pressure measurements as part of an urgent stroke therapy trial (treatment within 90 minutes of stroke onset).

SETTING

Thirteen hospitals in three metropolitan communities.

PARTICIPANTS

Sixty-nine patients (mean age, 65 +/- 9 years) with acute ischemic stroke who were participants in a phase I urgent stroke therapy trial of recombinant tissue plasminogen activator.

MAIN OUTCOME MEASURE

Blood pressures recorded at the scene of stroke by life-squad personnel, in the emergency department, and in the ICU.

RESULTS

The mean time from stroke onset to the time of first blood pressure measurement was 19 +/- 13 minutes. Twenty-four of the 69 patients in the urgent stroke therapy trial had an initial systolic blood pressure of at least 160 mm Hg. Of these, 23 had a significant decline in systolic and diastolic blood pressure during the first 90 minutes after the onset of stroke (mean change in systolic pressure, -29 +/- 22 mm Hg, P < .001; mean change in diastolic pressure, -10 +/- 14 mm Hg, P < .01). No patients received antihypertensive therapy during the time in which the decline in blood pressure was noted.

CONCLUSION

Mildly or moderately elevated blood pressure frequently declines spontaneously during the first minutes and hours of focal cerebral ischemia and generally does not require urgent pharmacologic treatment.

[Soluble interleukin 2 receptor as activity parameter in serum of systemic and discoid lupus erythematosus]

The evaluation of disease activity in systemic lupus erythematosus (SLE) is important for selection of the appropriate therapeutic regimen. In addition to the clinical picture, various laboratory parameters are taken into account. However, no validated criteria for the evaluation of the disease activity in SLE have yet been established. Recently, serum levels of soluble interleukin-2 receptor (sIL-2R) have been proposed as a potential parameter for disease activity in SLE. However, the studies reported on this subject so far have focused mainly on certain subsets of the disease, and the evaluation of the disease activity was based on a very limited number of parameters. In the present study, we determined serum levels of sIL-2R in 23 patients with SLE and 30 patients with discoid LE (DLE). Evaluation of disease activity in SLE was based on a comprehensive scale which considered numerous clinical signs and laboratory parameters. In SLE, serum levels of sIL-2R showed a better correlation with disease activity than all the other parameters investigated, including proteinuria, erythrocyte sedimentation rate, serum globulin concentration, titre of antibodies against double-stranded DNA, serum albumin concentration, serum complement levels and white blood cell count. For the first time, we report on elevated serum levels of sIL-2R in DLE, which also correlated with disease activity.

[Clarity in general practice]

A random sample of 224 consultations and interviews was analyzed, regarding the structuring and sequences in each consultation. Most space in the unbiased doctor's descriptions took anamnesis, followed by therapy, investigation, followed by physical examination and, least, diagnosis. Urban doctors kept the classic scheme of succeeding anamnesis, investigation, diagnosis and therapy more often than their rural colleagues. Explanations to patients were more frequently done by country doctors. The words doctors used to indicate communication are listed. The term of resonance phase in consultation is discussed. To achieve clarity in the consultation is important for doctor's stress prophylaxis.

Stereotaxic implantation of autologous adrenal medulla into caudate nucleus in four patients with parkinsonism. One-year follow-up

Four patients with levodopa-responsive parkinsonism (aged 26, 35, 45, and 49 years) received autologous adrenal medullary implants into or near the left caudate nucleus by stereotaxic implantation after flank adrenalectomy. All patients had an immediate response to implantation lasting several days, during which parkinsonian signs and symptoms decreased. This period was followed by a gradual reappearance of symptoms in all but one patient. This patient had had a dramatic increase in "on" time without dyskinesias and a decrease in the severity and duration of "off" time. He died of multifocal glioblastoma 1 year after transplantation. Autopsy revealed no surviving adrenal cells. In one case, the stereotaxic implantation missed the basal ganglia, resulting in the placement of the adrenal medullary tissue into the medial thalamus and near the third ventricle; the patient did not improve. In the other two cases, a modest but definite increase in "on" time without dyskinesia and a reduction in the severity and duration of "off" time has been observed. The role of autologous adrenal medullary transplantation in patients with parkinsonism remains to be determined. Patients with a family history of cerebral malignancy may be at increased risk for the development of transplant-induced malignancy.

Lead exposure from lead crystal

In a study of the elution of lead (Pb) from crystal decanters and glasses, port containing 89 micrograms Pb/l was placed in decanters and the Pb content of the wine rose steadily to 3518 micrograms/l after 4 months. Wines and spirits stored in crystal decanters for a long time contained Pb at concentrations up to 21,530 micrograms/l. In a short-term experiment white wine eluted small amounts of Pb from crystal glasses within minutes.

[Coincidence of hypertensive changes of the eye fundus and regulation disorders of peripheral microcirculation: I--Skin]

In cases of arterial hypertension, funduscopy is an established method of estimating systemic vascular lesions. In this study the relation between the extent of retinal vascular changes and dynamic processes in the microcirculation of the skin was investigated by nailfold capillaroscopy in 88 patients. With increasing vascular changes a progressive loss of vasodilator reserve and transcutaneous partial pressure was observed (no morphologic changes--fundus hypertonicus II--fundus hypertonicus III). It thus appears possible to evaluate the functional state of the macro- and microcirculation by funduscopy.

The hyperlipidemia of the nephrotic syndrome

Lipid abnormalities in patients with the nephrotic syndrome have long been recognized. However, the significance of these lipid abnormalities, the mechanisms producing them, and their potential treatment have all been a cause of debate. Recent data have helped clarify each of these areas of controversy. Studies of the lipoprotein abnormalities of patients with the uncomplicated nephrotic syndrome have shown that many will have elevated levels of total and low-density lipoprotein cholesterol, whereas only a few will have elevated levels of high-density lipoprotein cholesterol. If these lipid abnormalities have the same significance in this population as in other populations studied, then some patients with unremitting nephrotic syndrome will be at high risk for cardiovascular disease. The elevated cholesterol levels noted in the nephrotic syndrome are caused primarily by enhanced hepatic synthesis, with lesser contributions by decreased clearance and altered enzyme activities. The signal for enhanced hepatic lipogenesis may relate to changes in plasma albumin concentration, plasma oncotic pressure, a local effect of viscosity at the hepatic sinusoidal level, or a loss of urinary proteins or other liporegulatory substances. Recently, a number of short-term studies in nephrotic patients have documented the safety and efficacy of lipid-lowering drugs such as the bile acid-binding resins, probucol, and the HMGCoA (hydroxymethylglutaryl coenzyme A) reductase inhibitors.

Cognitive training in academically deficient ADDH boys receiving stimulant medication

This study evaluated the effectiveness of a 16-week intensive cognitive training program in stimulant-treated, academically deficient ADDH boys. Cognitive training focused exclusively on academic skills and tasks, and included attack strategy training as well as self-monitoring and self-reinforcement of problem-solving behaviors and response accuracy. Control groups included remedial tutoring plus medication, and medication alone. Despite the scope of the program, the results provided no support for the notion that academically based cognitive training ameliorates the performance and achievement of academically deficient ADDH youngsters. Further, this intervention did not enhance self-esteem or attributional perceptions of academic functioning. There was poor agreement between teacher ratings of academic competence and test score changes. The lack of concordance between measures, and the scarcity of academically deficient ADDH children are discussed.

Heat resistance, immunological and quantitative changes of neutrophil alkaline phosphatase in trisomy 21 pregnancies

Neutrophil alkaline phosphatase (NAP) was analysed in 25 pregnant women with trisomy 21 foetuses whose chromosomal aberration was recognized by cytogenetic study after amniocentesis. Enzyme investigation was performed at 20-22 weeks of gestation using cytochemical and biochemical techniques. Twenty-nine women at the same stage of normal pregnancies were selected as controls. In parallel, each mother was karyotyped. Ten subjects from each series underwent biochemical and immunological investigation: measurement of enzyme levels, thermostability study and immunological tests with alkaline phosphatase isoenzyme antibodies. NAP from pregnant women with trisomy 21 foetuses was characterized by: (1) a lower rate of enzyme activity, (2) a large amount of heat-stable enzyme (T = 56 degrees C for biochemical assays, T = 85 degrees C for cytochemical tests), and (3) a marked loss of liver antigenicity. These findings suggest the presence in trisomy 21 pregnancies of a non-specific alkaline phosphatase isoenzyme which appears as an "enzyme marker" in maternal circulating neutrophils.

An enzymatic marker in mothers of trisomy 21 children: neutrophil alkaline phosphatase

Neutrophil alkaline phosphatase (NAP) from 12 mothers of normal children was investigated and the results compared to those of 7 mothers with trisomy 21 offsprings, in an attempt to determine a parental molecular change in this chromosomal abnormality. The biochemical properties of the enzyme were analyzed by the procedures of isoenzyme characterization, i.e. enzyme assays, thermostability, inhibition patterns and slab gel electrophoresis. Immunological properties were determined on 5 samples from normal mothers and on the same sample number of mothers with affected children. In these latter NAP showed characteristics that were to some extent different from the ones of normal controls. The following changes were observed: highly significant loading of membrane and nucleus pellets in NAP activity, poor effect of inhibitors on thermostable component and immunodepletion measured by a significant decrease of the normal affinity for antiliver and antiplacental alkaline phosphatase antisera. These findings are discussed in the light of our knowledge of alkaline phosphatase isoenzymes.

Treatment of the hyperlipidemia of the nephrotic syndrome: a controlled trial

The hyperlipidemia of the nephrotic syndrome is often associated with elevated total and low-density lipoprotein (LDL) cholesterol levels and low or normal high-density lipoprotein (HDL) cholesterol levels. This pattern of hyperlipidemia has been associated with an increased risk of accelerated atherosclerosis in other populations. Despite extensive studies of diet and drug therapy in other populations, few such therapeutic studies exist in patients with the nephrotic syndrome. To investigate the effect of diet and lipid-lowering drugs on the lipoprotein-lipid profile of patients with unremitting nephrotic syndrome and marked hyperlipidemia, we conducted a controlled trial using two such drugs: colestipol and probucol. Colestipol lowered the mean total fasting plasma cholesterol of seven patients from 397 +/- 27 to 317 +/- 37 mg/dL, a 20.2% decrease, and lowered the LDL cholesterol from 398 +/- 28 to 203 +/- 18 mg/dL, a 31.9% decrease. It did not affect the HDL cholesterol level, and thus lowered the LDL-to-HDL cholesterol ratio. Probucol lowered the mean total cholesterol from 439 +/- 72 to 339 +/- 60 mg/dL, a 22.6% decrease, and the LDL cholesterol from 282 +/- 43 to 215 +/- 26 mg/dL, a 23.8% decrease. Although the HDL cholesterol was lowered from 49 +/- 9 to 43 +/- 7 mg/dL by probucol, a 12.2% decrease, the LDL-to-HDL cholesterol ratio still declined. Both drugs were well tolerated and proved safe in this short-term trial. Antihyperlipidemic therapy may well be indicated in certain patients with unremitting nephrotic syndrome.

Comparative investigation of the microcirculation in patients with hypertension and healthy adults

A total of 51 patients with arterial hypertension, 29 of which have renal dysfunction, were examined with regard to patient history, clinically, laboratory analysis and capillary microscopy. Compared to healthy adult patients with hypertension demonstrated a significant increase in the number of capillaries per millimeter of epidermis, while at the same time showing a significantly decreased erythrocyte column diameter. This observation was more pronounced the greater the degree of retinal vascular alteration (fundus hypertonicus). The duration of reactive hyperemia in response to three minutes of ischemia with a spygmonometer cuff was considerably shortened in patients with hypertension. Here as well, an increasing degree of retinal vascular alteration correlated with a decrease in reactive hyperemia to the point of no response at all. The blood fluidity of patients with arterial hypertension was significantly limited. The plasma viscosity as well as the erythrocyte aggregation were significantly elevated. Patients suffering from additional kidney dysfunction had even higher viscosities. There also appeared to be a correlation to the degree of fundus hypertonicus in which the plasma viscosity increased in relation to an increasing degree of retinal vascular alteration.

[Primary management of newborn infants with respiratory failure due to a congenital defect of the diaphragm]

The authors report on 36 premature and term infants with congenital defects of the diaphragm, including 17 patients who developed a severe respiratory insufficiency either immediately after birth or during the first 30 minutes of life. The overall mortality rate was 64%; the results of treatment were marked by a particularly high mortality rate among the patients with early respiratory insufficiency: out of 17 patients, 12 died. The evaluation of the courses confirmed that adequate preoperative primary care is of major prognostic importance in patients with early respiratory insufficiency. On the basis of personal experience the authors have formulated the following recommendations for improving diagnosis and therapy at this stage of care: greater use of sonography examination methods for antepartal diagnosis of congenital defects of the diaphragm, making it possible to treat the corresponding high-risk pregnancies at an early stage in clinics equipped for neonatologic and pediatric surgical treatment; early intubation respiration with a ventilation technique which does not overstrain the patient, in newborns with abnormal respiration and suspected congenital defects of the diaphragm; the great diagnostic importance of plain radiographs of the thorax and abdomen; neonatologic and intensive medical stabilization treatment in patients with severely suppressed metabolism prior to the anesthesiologic and surgical stress of closure of the diaphragm defect.

Recognition of vesicular lipoproteins by the apolipoprotein B,E receptor of cultured fibroblasts

Vesicular lipoproteins (e.g., lipoprotein-X) are found in plasma in cholestasis or following infusion of Intralipid or phospholipid. To investigate the metabolism of vesicular lipoproteins, we isolated them from the plasma of subjects with cholestasis or following chronic or single Intralipid infusion. Cholestasis and chronic Intralipid therapy were found to be associated with elevated plasma concentrations of apoE, as determined by radioimmunoassay. Vesicular lipoproteins purified from each of the three types of plasma contained apoE, as well as other proteins. In cholestasis, in which levels of apoE were up to five times normal, a major portion of the plasma apoE was on vesicular lipoproteins. Normalized for apoE content, all preparations of vesicular lipoproteins displaced 125I-labeled LDL from apoB,E receptors of cultured fibroblasts identically. This displacement was inhibited by monoclonal antibodies that block receptor binding of apoE. Vesicular lipoproteins containing 125I-labeled apoE were internalized and degraded by fibroblasts. Different preparations caused small losses or gains of cellular cholesterol, with appropriate stimulation or suppression of apoB,E receptors. Thus, vesicular lipoproteins contain apoE, and apoE mediates their interaction with the apoB,E receptor. Our results suggest that the catabolism of cholesterol-rich vesicular lipoproteins, formed during cholestasis or following infusions of Intralipid or phospholipid, may be receptor-mediated.

Radioactive iodine treatment of metastatic thyroid carcinoma with clinical thyrotoxicosis

We present a case of well-differentiated follicular carcinoma of the thyroid with hyperfunctioning metastases and clinical thyrotoxicosis. The recommended I-131 treatment dose for patients with widespread bone metastases from thyroid carcinoma is 200 mCi. However, in a patient with hyperfunctioning metastatic tumor and increased radioiodine uptake, the treatment dose should be modified. Radiation dosimetry measurements performed on the patient in this study demonstrated that 132 mCi would be a safe therapeutic I-131 dose which would avoid injury to normal radiosensitive tissues. Consequently, she was given a 130-mCi therapeutic dose.