Soluble-insoluble transition in binary heterogeneous nucleation

In this Letter, we report the first experimental study of binary heterogeneous gas-liquid nucleation. Onset activities were obtained for nucleation of various n-propanol-water vapor mixtures on 6.9 nm NaCl particles soluble in water and practically insoluble in n-propanol. The Fletcher theory of vapor nucleation on insoluble particles provided a reasonable approximation for n-propanol rich mixtures only, whereas the Köhler theory of activation of soluble particles worked only for water rich mixtures. A new theory was formulated providing a satisfactory description of the transition from activation of soluble particles to vapor nucleation on insoluble particles.

Magnetic resonance imaging volumes of the hippocampus and the amygdala in women with borderline personality disorder and early traumatization

BACKGROUND

Based on findings of stress-induced neural disturbances in animals and smaller hippocampal volumes in humans with posttraumatic stress disorder), we hypothesized that patients with borderline personality disorders (BPD), who often are victims of early traumatization, have smaller volumes of the hippocampus and the amygdala. We assumed that volumes of these brain regions are negatively correlated with traumatic experiences and with neuropsychological deficits.

METHODS

We studied 21 female patients with BPD and a similar group of healthy controls. We performed clinical assessments, a modified version of the Childhood Trauma Questionnaire, and magnetic resonance imaging volumetric measurements of the hippocampus, amygdala, temporal lobes, and prosencephalon. Neuropsychological testing included scales on which disturbances in BPD were previously reported.

RESULTS

The patients with BPD had nearly 16% smaller volumes of the hippocampus (P<.001) and 8% smaller volumes of the amygdala (P<.05) than the healthy controls. The results for both hemispheres were nearly identical and were controlled for the volume of the prosencephalon and for head tilts. The volumes of the hippocampus were negatively correlated with the extent and the duration of self-reported early traumatization only when BPD and control subjects were considered together. Levels of neuropsychological functioning were associated with the severity of depression but not with the volumes of the hippocampus.

CONCLUSION

In female patients with BPD, we found reduction of the volumes of the hippocampus (and perhaps of the amygdala), but the association of volume reduction and traumatic experiences remains unclear. Arch Gen Psychiatry. 2000;57:1115-1122.

Correlates of figure-ground segregation in fMRI

We investigated which correlates of figure-ground-segregation can be detected by means of functional magnetic resonance imaging (fMRI). Five subjects were scanned with a Siemens Vision 1.5 T system. Motion, colour, and luminance-defined checkerboards were presented with alternating control conditions containing one of the two features of the checkerboard. We find a segregation-specific activation in V1 for all subjects and all stimuli and conclude that neural mechanisms exist as early as in the primary visual cortex that are sensitive to figure-ground segregation.

IL-3 increases production of B lymphoid progenitors from human CD34+CD38- cells

The effect of IL-3 on the B lymphoid potential of human hemopoietic stem cells is controversial. Murine studies suggest that B cell differentiation from uncommitted progenitors is completely prevented after short-term exposure to IL-3. We studied B lymphopoiesis after IL-3 stimulation of uncommitted human CD34+CD38- cells, using the stromal cell line S17 to assay the B lymphoid potential of stimulated cells. In contrast to the murine studies, production of CD19+ B cells from human CD34+CD38- cells was significantly increased by a 3-day exposure to IL-3 (p < 0.001). IL-3, however, did not increase B lymphopoiesis from more mature progenitors (CD34+CD38+ cells) or from committed CD34-CD19+ B cells. B cell production was increased whether CD34+CD38- cells were stimulated with IL-3 during cocultivation on S17 stroma, on fibronectin, or in suspension. IL-3Ralpha expression was studied in CD34+ populations by RT-PCR and FACS. High IL-3Ralpha protein expression was largely restricted to myeloid progenitors. CD34+CD38- cells had low to undetectable levels of IL-3Ralpha by FACS. IL-3-responsive B lymphopoiesis was specifically found in CD34+ cells with low or undetectable IL-3Ralpha protein expression. IL-3 acted directly on progenitor cells; single cell analysis showed that short-term exposure of CD34+CD38- cells to IL-3 increased the subsequent cloning efficiency of B lymphoid and B lymphomyeloid progenitors. We conclude that short-term exposure to IL-3 significantly increases human B cell production by inducing proliferation and/or maintaining the survival of primitive human progenitors with B lymphoid potential.

Competitive cytokeratin 19 RT-PCR for quantification of breast cancer cells in blood cell suspensions

Detection of residual tumor cells in BM and PBPC products has been correlated with worse outcome of breast cancer patients. Still, there is a considerable demand for studies investigating the influence of the actual tumor cell number on prognosis, as quantification routinely has been cumbersome and time consuming and, thus, was evaded. We developed and evaluated a competitive RT-PCR-ELISA assay for cytokeratin 19 (CK19) with standard curve quantification that allows quantification of multiple samples within a working day; mRNA isolation, RT-PCR reaction, and automated ELISA detection were carried out using commercial kits. Results were expressed as OD420nm ratios of CK19 and an internal competitor. Values were then converted into tumor cell numbers using a standard curve of MCF-7 tumor cells. The assay had high specificity because of primers and capture probes with great heterogeneity to both published pseudogenes, which was confirmed by BLAST sequence alignment. We achieved a sensitivity of detecting 1 tumor cell per 10(6) mononuclear cells (MNC). Between-batch precision (n = 8) for quantification was consistent and reasonable, with a coefficient of variation around 25%. Therefore, this assay should be suitable and sufficient for routine quantification of tumor cell numbers in BM or PBPC samples.

An optical coherence microscope for 3-dimensional imaging in developmental biology

An optical coherence microscope (OCM) has been designed and constructed to acquire 3-dimensional images of highly scattering biological tissue. Volume-rendering software is used to enhance 3-D visualization of the data sets. Lateral resolution of the OCM is 5 mm (FWHM), and the depth resolution is 10 mm (FWHM) in tissue. The design trade-offs for a 3-D OCM are discussed, and the fundamental photon noise limitation is measured and compared with theory. A rotating 3-D image of a frog embryo is presented to illustrate the capabilities of the instrument.

Constitutive HOXA5 expression inhibits erythropoiesis and increases myelopoiesis from human hematopoietic progenitors

The role of the homeobox gene HOXA5 in normal human hematopoiesis was studied by constitutively expressing the HOXA5 cDNA in CD34(+) and CD34(+)CD38(-) cells from bone marrow and cord blood. By using retroviral vectors that contained both HOXA5 and a cell surface marker gene, pure populations of progenitors that expressed the transgene were obtained for analysis of differentiation patterns. Based on both immunophenotypic and morphological analysis of cultures from transduced CD34(+) cells, HOXA5 expression caused a significant shift toward myeloid differentiation and away from erythroid differentiation in comparison to CD34(+) cells transduced with Control vectors (P =.001, n = 15 for immunophenotypic analysis; and P <.0001, n = 19 for morphological analysis). Transduction of more primitive progenitors (CD34(+)CD38(-) cells) resulted in a significantly greater effect on differentiation than did transduction of the largely committed CD34(+) population (P =.006 for difference between HOXA5 effect on CD34(+) v CD34(+)CD38(-) cells). Erythroid progenitors (burst-forming unit-erythroid [BFU-E]) were significantly decreased in frequency among progenitors transduced with the HOXA5 vector (P =.016, n = 7), with no reduction in total CFU numbers. Clonal analysis of single cells transduced with HOXA5 or control vectors (cultured in erythroid culture conditions) showed that HOXA5 expression prevented erythroid differentiation and produced clones with a preponderance of undifferentiated blasts. These studies show that constitutive expression of HOXA5 inhibits human erythropoiesis and promotes myelopoiesis. The reciprocal inhibition of erythropoiesis and promotion of myelopoiesis in the absence of any demonstrable effect on proliferation suggests that HOXA5 diverts differentiation at a mulitpotent progenitor stage away from the erythroid toward the myeloid pathway.

Primary central nervous system lymphoma: from clinical presentation to diagnosis

Immunocompetent patients with primary central nervous system lymphoma (PCNSL) present with a median age of 55 years, immunosuppressed patients with a median age of 40 years. They show a broad range of signs and symptoms. Symptoms of increased intracranial pressure and personality change are most frequent, followed in frequency by ataxia and hemiparesis. The median time from onset of symptoms to diagnosis is 3-5 months in immunocompetent patients and 2 months in immunodeficient patients. The time to diagnosis can be considerably longer in patients with slowly developing personality change or fluctuating symptoms due to spontaneous or steroid-induced remission of so-called sentinel lesions. Native CT scans show iso- or hyperdense lesions with homogenous contrast enhancement. T1-weighted MRI scans show hypointense and T2-weighted scans hyperintense lesions. The definitive diagnosis of PCNSL requires biopsy. In some cases, however, the definitive diagnosis may exclusively be made by the demonstration of malignant B-lymphocytes in the cerebrospinal fluid.

Endogenous serum levels of thrombopoietic cytokines in healthy whole-blood and platelet donors: implications for plateletpheresis

Serum concentrations of the thrombopoiesis-enhancing cytokines thrombopoietin (TPO), erythropoietin (EPO), interleukin (IL)-6 and IL-11 were determined in 119 healthy whole-blood (WBD) and 101 platelet donors (PD) prior to donation. The 90% TPO reference interval in WBD of 64-867 pg/ml (median 163, 100% range 45-7572) was significantly higher than in PD of 56-524 (median 122, range 44-801, P = 0.004), whereas their platelet counts were lower (P < 0.001). EPO levels were not different (WBD 7.7 +/- 3.8, PD 8.0 +/- 4.9 IU/l), IL-6 and IL-11 were below the detection limit in >/=90% of cases (IL-6 < 3.2 pg/ml, IL-11 < 31.2 pg/ml). None of the cytokines correlated with platelet counts, other blood parameters, or in the PD group with the frequency of platelet donations within the last 6 months. We conclude that plateletpheresis does not lead to a lasting increase of thrombopoietic cytokines and provide reference data for potential platelet mobilization strategies with recombinant growth factors.

Selective color constancy deficits after circumscribed unilateral brain lesions

The color of an object, when part of a complex scene, is determined not only by its spectral reflectance but also by the colors of all other objects in the scene (von Helmholtz, 1886; Ives, 1912; Land, 1959). By taking global color information into account, the visual system is able to maintain constancy of the color appearance of the object, despite large variations in the light incident on the retina arising from changes in the spectral content of the illuminating light (Hurlbert, 1998; Maloney, 1999). The neural basis of this color constancy is, however, poorly understood. Although there seems to be a prominent role for retinal, cone-specific adaptation mechanisms (von Kries, 1902; Pöppel, 1986; Foster and Nascimento, 1994), the contribution of cortical mechanisms to color constancy is still unclear (Land et al., 1983; D'Zmura and Lennie, 1986). We examined the color perception of 27 patients with defined unilateral lesions mainly located in the parieto-temporo-occipital and fronto-parieto-temporal cortex. With a battery of clinical and specially designed color vision tests we tried to detect and differentiate between possible deficits in central color processing. Our results show that color constancy can be selectively impaired after circumscribed unilateral lesions in parieto-temporal cortex of the left or right hemisphere. Five of 27 patients exhibited significant deficits in a color constancy task, but all of the 5 performed well in color discrimination or higher-level visual tasks, such as the association of colors with familiar objects. These results indicate that the computations underlying color constancy are mediated by specialized cortical circuitry, which is independent of the neural substrate for color discrimination and for assigning colors to objects.

3D spiral CT imaging of bone anomalies in a case of diastematomyelia

The case of a 48-year-old woman, suffering from a diastematomyelia, is presented. This case and the diagnostic findings are used to demonstrate the demands on imaging methods with respect to a new classification of split cord malformations (SCMs) recently published. Although MRI is the method of choice for imaging of the spinal cord generally, only X-ray methods and especially conventional computer tomography provide the information necessary for correct classification of SCMs. Additional 3D-reconstructions from suitable CT-data are helpful in visualizing complex anomalies of bony structures found in most cases of SCM.

Acute disseminated encephalomyelitis following Pontiac fever

We report the case of a 35-year-old woman who developed headache and psychosis and gradually became comatose within 3 weeks after a flu-like infection. MRI revealed bifrontal demyelination consistent with acute disseminating encephalomyelitis (ADEM). Two different cerebrospinal fluid samples were positively tested for Legionella cincinnatiensis by direct sequencing of a PCR-amplified Legionella-specific fragment. This result made it possible to interpret the initial symptoms as Pontiac fever. We think it most likely that this is a case of ADEM following the very rare situation of a systemic infection with L. cincinnatiensis. A review of the literature on Legionella-associated encephalopathy suggests that some of these cases may also have had ADEM.

Safety and toxicity of amphotericin B in glucose 5% or intralipid 20% in neutropenic patients with pneumonia or fever of unknown origin: randomised study

OBJECTIVE

To compare the feasibility of treatment, safety, and toxicity of intravenous amphotericin B deoxycholate prepared in either glucose or intralipid for empirical antimycotic treatment of neutropenic cancer patients.

DESIGN

Single centre stratified, randomised non-blinded phase II study.

SETTING

University hospital providing tertiary clinical care.

SUBJECTS

51 neutropenic patients (leukaemia (35), lymphoma (11), solid tumours (5)) with refractory fever of unknown origin (24) or pneumonia (27).

INTERVENTIONS

Amphotericin B 0.75 mg/kg/day in 250 ml glucose 5% solution or mixed with 250 ml intralipid 20%, given on eight consecutive days then alternate days, as a 1-4 hour infusion.

MAIN OUTCOME MEASURES

Feasibility of treatment, subjective tolerance (questionnaire), and objective toxicity (common toxicity criteria of the National Cancer Institute).

RESULTS

Study arms were balanced for age, sex, underlying malignancy, renal and liver function, and pre- and concomitant treatment with antibiotics and nephrotoxic agents. No statistically significant or clinically relevant differences were found between the treatment groups for: daily or cumulative dose and duration of treatment with amphotericin B; incidence and time of dose modifications or infusion duration changes related to toxicity; dose or duration of symptomatic support with opiates, antipyretics, or antihistamines; renal function; subjective tolerance; most common toxicity scores; course of infection; and incidence of treatment failures. Patients treated with amphotericin B in intralipid were given fewer diuretics (P<0.05) and therefore had more peripheral oedema (P<0.01) and needed less potassium supplementation (P<0.05) than patients given amphotericin in glucose. Acute respiratory events were more common in the intralipid arm (P<0.05).

CONCLUSIONS

Amphotericin B 0.75 mg/kg/day in intralipid given on eight consecutive days then alternate days provides no benefit and is associated with potential pulmonary side effects possibly because of fat overload or an incompatibility of the two drugs.

Deficits and recovery of first- and second-order motion perception in patients with unilateral cortical lesions

Unilateral lesions in the posterior parietal cortex can degrade motion perception in the contralesional visual hemifield. Our aim was to investigate whether deficits caused by cortical lesions may be different for first- and second-order motion perception, and to study the time scale of any potential recovery. In nine patients with circumscribed lesions mainly in the parietal and fronto-parietal cortex, thresholds for direction discrimination were measured for stimuli presented peripherally in their ipsi- and contralesional hemifield. Subjects had to identify the direction of a vertically moving object embedded in a background of dynamic random dot noise. The object consisted of various proportions of signal and noise dots. Signal dots were either (a) coherently moving in the same direction as the object (first-order), (b) stationary (second-order: drift-balanced), or (c) coherently moving in the opposite direction (second-order: theta). Noise dots were flickering. Two patients showed significant threshold elevations for all three types of motion stimuli presented in their contralesional hemifield, while thresholds for ipsilesional targets were unaffected. Neither showed any selective deficit of first- versus second-order motion perception, but second-order motion was more impaired. Their lesions probably included the motion area V5-MT, which was spared in the other seven patients. One of the patients, who was retested several times during a 27-month postlesional period, showed complete recovery for first- and second-order motion direction discrimination, as well as for the detection of speed differences.

Lesion location influences perception of homonymous scotomata during flickering random dot pattern stimulation

An attempt was made to clarify whether the site of postchiasmal lesions affects subjective perception of homonymous visual field defects during stimulation with flickering random dot patterns (white noise-field). Out of 56 patients with homonymous hemianopia, 38 (68%) perceived scotomata in this situation, but 18 (32%) discerned none at all. Neuroradiologic superposition of cerebral lesions detected by computed tomography (CT) or magnetic resonance imaging (MRI) showed that nearly all patients who perceived their scotomata had lesions involving the primary visual cortex or the perigeniculate region, whereas those who received no scotoma had lesions centered within the optic radiation. Functional MRI of six normal subjects during stimulation with flickering random dot patterns indicated predominant activation of the primary visual cortex. Since noise-field defects were most frequently perceived by patients whose lesion involved the primary visual cortex, it appears that the sensitivity of noise-field campimetry depends on the site of damage in the visual pathway. The explanation for this may be that damage to long-range horizontal connections impairs filling-in processes.

Clinical presentation and therapeutic outcome in 26 patients with primary CNS lymphoma

This retrospective study analyzes clinical features and therapeutic outcome in 26 immunocompetent patients with primary central nervous system lymphoma (PCNSL). Most patients presented with personality changes. PCNSL lesions were mainly iso- or hyperdense, enhancing lesions on CT scan, hypointensive on T1-, and hyperintensive on T2-weighted MRI. Multiple lesions were found in about 60% of patients. Nine of 11 patients receiving radiotherapy alone showed complete remission (CR). Median survival time after diagnosis (MST) was 13 months. Seven patients received intravenous and intrathecal methotrexate, radiotherapy, and postirradiation intravenous cytarabine. Six of these patients had CR and 5 patients are alive in CR after a median follow-up of 12 months. Five patients received various other radiochemotherapy regimens (MST 6 months), and 3 patients died before receiving any radio- or chemotherapy. Our preliminary treatment results show a tendency to improved survival with radiochemotherapy. This is consistent with pertinent data from the literature which favors radiochemotherapy for patients with PCNSL.

Sustained decrease of peripheral lymphocytes after allogeneic blood stem cell aphereses

48 healthy donors underwent peripheral blood stem cell (PBSC) apheresis for allogeneic transplantation beginning on day 4 of G-CSF (2 x 5 microg/kg) mobilization. In one to four (median two) large-volume mononuclear cell aphereses, a median of 55.9 x 10(9) of lymphocytes (range 21.0-109.2 x 10[9]) were collected, an amount comparable to lymphocyte numbers removed by therapeutic lymphaphereses in autoimmune diseases. Mean peripheral lymphocyte counts decreased from premobilization values of 2.31 x 10(9)/l to 1.31 x 10(9)/l at a median of 34 d (1 month) and 1.53 x 10(9)/l at a median of 327 d (11 months). The decrease in peripheral lymphocyte counts was significantly correlated with the number of lymphocytes removed and the number of aphereses. Neutrophil and platelet counts returned to normal values after 1 month whereas monocyte counts and haemoglobin concentrations were significantly decreased at 1 month but not at 11 months.

False perception of motion in a patient who cannot compensate for eye movements

We are usually unaware of the motion of an image across our retina that results from our own movement. For instance, during slow-tracking eye movements we do not mistake the shift of the image projected onto the retina for motion of the world around us, but instead perceive a stable world. Following early suggestions by von Helmholtz, it is commonly believed that this spatial stability is achieved by subtracting the retinal motion signal from an internal reference signal, such as a copy of the movement command (efference copy). Object motion is perceived only if the two differ. Although this concept is widely accepted, its anatomical underpinning remains unknown. Here we describe the case of a patient with bilateral extrastriate cortex lesions, suffering from false perception of motion due to an inability to take eye movements into account when faced with self-induced retinal image slip. This is indicated by the fact that during smooth-pursuit eye movements, he perceives motion of the stationary world at a velocity that corresponds to the velocity of his eye movement; that is, he perceives the raw retinal image slip uncorrected for his own eye movements. We suspect that this deficiency reflects damage of a distinct parieto-occipital region that disentangles self-induced and externally induced visual motion by comparing retinal signals with a reference signal encoding eye movements and possibly ego-motion in general.