Spatial dependency of the PPG morphology at right carotid common artery.

PhotoPlethysmoGraphy (PPG) is ubiquitously employed in wearable devices for health monitoring. Photodiode signal inversion is observed in rare occasions, most of the time when the sensor is pressed against the skin. We report in this article such observations made at the right common carotid artery site. Indeed we have systematically observed a photodiode signal inversion when the PPG sensor is placed where the pulse is the best felt at the carotid. In addition to be inverted, the pulse is steeper during the systolic phase. Such inversion has implications in terms of pulse arrival time (PAT) measurements In our experiments, this causes a difference of 20 ms in the carotid PAT when measured at the absolute maximum slope. The mechanical and optical properties of tissues must be better accounted to explain the PPG signal morphology. Clinical Relevance- Understanding the role of mechanical tissue properties seems relevant in order to obtain more reproducible results in PPG signal analysis.

Evaluation of a dual-PPG system for pulse transit time monitoring.

This work presents a new dual-photoplethysmographic (PPG) system for pulse transit time (PTT) monitoring. An experiment has been set up in order to compare the PTT measurement between carotid and radial arteries from two systems: our physiological multimodal platform (PMP) and the Complior® tonometer. This work explores the comparison between such optical and mechanical modalities. The results show that the PPG device tends to overestimate the PTT (RMSE = 16 ms). Furthermore, both mechanical and optical signals have been superposed and demonstrated that pulse morphologies are quite similar.Clinical Relevance-Carotid-radial pulse wave velocity (PWV) is compared on a small cohort of subjects and significant differences are observed between optical and mechanical-based systems.

Blood pressure measurement by coupling an external pressure and photo-plethysmographic signals.

This work presents a new technique for the noninvasive measurement of systolic blood pressure (sBP), mean blood pressure (mBP) and diastolic blood pressure (dBP) using photo-plethysmographic (PPG) sensors when an artery is exposed to an external pressure. Two sets of experiments were performed: a first study combining PPG with an oscillometric device and the second combining PPG with a force/pressure sensor. These two experiments enable the estimation of BP values. PPG results were found to be comparable to oscillometric results, with bias and precision errors of -0.81 and 5.26 for sBP, 1.12 and 5.61 for mBP and 1.67 and 9.09 for dBP (n = 28). Furthermore, amplification over the brachial-to-finger path was found to be 1.02 ± 0.08 for mBP (n = 20) confirming that mBP does not undergo any amplification along the arterial tree whereas, for sBP, an amplification of 1.20 ± 0.12 (n = 7) was found for green wavelength, 1.35 ± 0.09 (n = 6) for red wavelength and 1.36 ± 0.09 (n = 6) for infrared wavelength. Thus, amplification for sBP is bigger for red and infrared wavelengths compared to green one.

Autoimmune hemolysis and immune thrombocytopenic purpura after cord blood transplantation may be life-threatening and warrants early therapy with rituximab.

Autoimmune hemolysis (AH) and immune thrombocytopenic purpura (ITP) are recognized complications after cord blood transplantation (CBT). We evaluated the incidence and characteristics of AH/ITP after double-unit CBT in a day 100 landmark analysis of 152 patients (median age 36 years, range 0.9-70 years) transplanted for hematologic malignancies with myeloablative or nonmyeloablative conditioning and calcineurin inhibitor (CNI)/mycophenolate mofetil. With a median 5.2-year (range 1.6-9.7 years) survivor follow-up, 10 patients developed autoimmune cytopenias (8 AH, 1 ITP, 1 both) at a median of 10.4 months (range 5.8-24.5) post CBT for a 7% cumulative incidence 3 years after the day 100 landmark. Six patients presented with severe disease (hemoglobin ⩽6 g/dL and/or platelets <20 × 109/L). All AH patients were direct antiglobulin test positive. All 10 cases developed during immunosuppression taper with 8 having prior acute GVHD. All 10 patients received rituximab 2-18 days after diagnosis, and corticosteroids combined with rituximab within <7 days was the most effective. No patient died of AH/ITP. AH/ITP occurs infrequently after CBT but may be life-threatening requiring emergency therapy. Rituximab combined with corticosteroids at diagnosis is warranted in patients with severe disease.

Donor-recipient allele-level HLA matching of unrelated cord blood units reveals high degrees of mismatch and alters graft selection.

The feasibility of selecting cord blood (CB) units at high-resolution HLA match has not been investigated. We analyzed the high-resolution donor-recipient HLA match of 100 double-unit 4-6/6 HLA-A,-B antigen, -DRB1 allele-matched CB grafts (units 1a and 1b) and their back-up units (n=377 units in total). The median cryopreserved graft dose was 2.9 × 10(7)/kg/unit, and at high resolution these units had a median donor-recipient HLA-allele match of 5/8 (range 2-8/8) and 6/10 (range 2-9/10), respectively. We then evaluated how often use of high-resolution HLA-match criteria would change the original graft selection to substitute one or both of the back-up units for units 1a and/or 1b. On using a model in which both a higher eight-allele HLA match and a cell dose ⩾ 2.0 × 10(7)/kg/unit were required, graft selection changed in 33% of transplants with minimal effect on cell dose (8.3% reduction). In summary, while units chosen based on HLA-A,-B antigen and -DRB1 allele match have substantial mismatch at higher resolution, CB selection based on high-resolution HLA match is possible in a significant proportion of patients without compromise in cell dose.

Graft-versus-host disease after double-unit cord blood transplantation has unique features and an association with engrafting unit-to-recipient HLA match.

Manifestations of and risk factors for graft-versus-host disease (GVHD) after double-unit cord blood transplantation (DCBT) are not firmly established. We evaluated 115 DCBT recipients (median age, 37 years) who underwent transplantation for hematologic malignancies with myeloablative or nonmyeloablative conditioning and calcineurin inhibitor/mycophenolate mofetil immunosuppression. Incidence of day 180 grades II to IV and III to IV acute GVHD (aGVHD) were 53% (95% confidence interval, 44 to 62) and 23% (95% confidence interval, 15 to 31), respectively, with a median onset of 40 days (range, 14 to 169). Eighty percent of patients with grades II to IV aGVHD had gut involvement, and 79% and 85% had day 28 treatment responses to systemic corticosteroids or budesonide, respectively. Of 89 engrafted patients cancer-free at day 100, 54% subsequently had active GVHD, with 79% of those affected having persistent or recurrent aGVHD or overlap syndrome. Late GVHD in the form of classic chronic GVHD was uncommon. Notably, grades III to IV aGVHD incidence was lower if the engrafting unit human leukocyte antigen (HLA)-A, -B, -DRB1 allele match was >4/6 to the recipient (hazard ratio, 0.385; P = .031), whereas engrafting unit infused nucleated cell dose and unit-to-unit HLA match were not significant. GVHD after DCBT was common in our study, predominantly affected the gut, and had a high therapy response, and late GVHD frequently had acute features. Our findings support the consideration of HLA- A,-B,-DRB1 allele donor-recipient (but not unit-unit) HLA match in unit selection, a practice change in the field. Moreover, new prophylaxis strategies that target the gastrointestinal tract are needed.

Importance of day 21 BM chimerism in sustained neutrophil engraftment following double-unit cord blood transplantation.

Delayed or failed engraftment remains a concern after cord blood transplantation (CBT) even when using double-unit grafts. Therefore, we analyzed the association between BM assessment performed approximately 21 days after transplantation, and the speed and success of sustained donor-derived neutrophil engraftment in 56 myeloablative double-unit CBT (DCBT) recipients. Overall, the cumulative incidence of sustained neutrophil engraftment was 95% (95% confidence intervals (CI): 89-100). Of the percentage of myeloid precursors, the BM cellularity and the total donor chimerism the total donor chimerism percentage had the most critical association with the speed and success of engraftment. DCBT recipients who were 100% donor achieved a 98% engraftment rate at a median of 22 days. This compared with 100% engraftment in patients who were 90-99% donor, but at a delayed median of 29 days and only 68% engraftment in patients <90% donor at a median of 37 days (P=0.001). Multivariate analysis was performed in the subgroup of patients who had not engrafted at the time the BM analysis was performed, the subgroup of most clinical concern. This confirmed donor chimerism was predictive of subsequent neutrophil recovery (P=0.004). These findings demonstrate the importance of the day 21 BM chimerism determinations after DCBT.

Preservation of ultrastructure and antigenicity for EM immunocytochemistry following intracellular recording and labeling of single cortical neurons in brain slices.

Knowledge of the distribution of neurotransmitters, neuromodulators, and transmitter receptors operating at specific synaptic sites on cortical neurons is essential for understanding the precise mechanisms that underlie the dynamic properties of cortical microcircuitry. We report on a new combination of techniques for analyzing chemically-specified synaptic input to individual cortical neurons first electrophysiologically characterized in the in vitro brain slice preparation. We tested the feasibility of this approach by performing intracellular recordings and biocytin injections in guinea pig medial prefrontal cortex slices and then by performing dual preembedding immunocytochemistry in order to localize neuronal nitric oxide synthase relative to single biocytin-filled neurons. The recorded cell and nitric oxide synthase immunoreactivity were visualized by light and electron microscopy utilizing both peroxidase and silver intensified gold stains. Single neurons were also dually visualized with fluorescence for light microscopy and with silver intensified gold for electron microscopy. Our findings indicate that both antigenicity and ultrastructure can be well preserved in tissue first used for in vitro slice experiments. This combination of methods should be widely applicable for analyzing the subcellular distribution of neuronal molecules such as receptors, channels and enzymes on physiologically characterized mammalian neurons.

The subcellular distribution of nitric oxide synthase relative to the NR1 subunit of NMDA receptors in the cerebral cortex.

Results from several electrophysiological studies predict that the neuronal NO-synthesizing enzyme, nNOS, resides within spines formed by pyramid-to-pyramid axo-spinous synaptic junctions of the cortex. On the other hand, light microscopic neuroanatomical detection of nNOS within pyramidal neurons has been difficult, suggesting that these neurons contain nNOS at levels below threshold for detection. Our results obtained by electron microscopic immunocytochemistry indicate that nNOS occurs within spiny neurons, such as those of pyramidal neurons, albeit discretely within their spines. Dual electron microscopic immunocytochemistry, whereby antigenic sites to the NR1 subunit of NMDA receptors are probed simultaneously with sites immunoreactive for nNOS, reveals that some, although not all, nNOS within spines co-exist with NR1 subunits. Additionally, immunoreactivity for the NR1 subunit is detectable within nNOS-axons, indicating that NO may be generated in response to axo-axonic interactions with glutamatergic axons in the vicinity and independently of action potential propagation. Immunoreactivity for NR1 subunits within axons (with or without nNOS-immunoreactivity) may additionally serve to confer receptivity of these axons to NO generated coincidentally with activity. Analysis of the visual cortex of monocular adult animals indicates that the level of nNOS within neurites is dependent on chronic activity levels of the surrounding neuropil and independent of somatic input level. Together, these findings point to plasticity of nNOS neurons within adult brain tissue, involving regulation of subcellular nNOS distribution.

Effects of diet supplementation with wheat bran on serum estrogen levels in the follicular and luteal phases of the menstrual cycle.

There is both epidemiologic and experimental support for the hypothesis that a high-fiber diet can reduce breast cancer risk; this may be due, at least in part, to a reduction in circulating estrogens. This study examined the effects of three levels of wheat bran supplementation (5, 10, and 20 g/d for 2 mo) on the major serum estrogens during both the luteal and follicular phases of the menstrual cycle. The 10- and 20-g supplements, which increased the total dietary fiber intakes to approximately 20 and 32 g/d, respectively, resulted in significant decreases in the luteal serum estrone (P < 0.05 and < 0.02, respectively). The serum estradiol was significantly reduced in the 10-g wheat bran group after 2 mo (P < 0.05); the 20-g supplemented group showed a significant decrease in estradiol at 1 mo (P < 0.02), but not at 2 mo. No changes occurred in the estrone sulfate concentrations. During the follicular phase, the 10-g wheat bran group exhibited a significant reduction in the serum estrone (P < 0.02). Only the serum estrone sulfate showed any reduction with the 20-g supplement, and this just failed to achieve significance (P = 0.07). Serum sex hormone-binding globulin levels were unaffected by wheat bran. When of long duration, these effects may be sufficient to favorably influence breast cancer risk in Western women.

NMDA-R1 subunit of the cerebral cortex co-localizes with neuronal nitric oxide synthase at pre- and postsynaptic sites and in spines.

The majority of nitric oxide's (NO) physiologic and pathologic actions in the brain has been linked to NMDA receptor activation. In order to determine how the NO-synthesizing enzyme within brain, neuronal NO synthase (nNOS), and NMDA receptors are functionally linked, previous studies have used in situ hybridization techniques in combination with light microscopic immunocytochemistry to show that the two are expressed within single neurons. However, this light microscopic finding does not guarantee that NMDA receptors are distributed sufficiently close to nNOS within single neurons to allow direct interaction of the two. Thus, in this study, dual immuno-electron microscopy was performed to determine whether nNOS and NMDA receptors co-exist within fine neuronal processes. We show that nNOS and the obligatory subunit of functional NMDA receptors, i.e. the NMDA-R1, co-exist within dendritic shafts, spines and terminals of the adult rat visual cortex. Axon terminals form asymmetric synaptic junctions with the dually labeled dendrites, suggesting that the presynaptic terminals release glutamate. Axons and dendrites expressing one without the other also are detected. These results indicate that it is possible for the generation of NO to be temporally coordinated with glutamatergic synaptic transmission at axo-dendritic and axo-axonic junctions and that NO may be generated independently of glutamatergic synaptic transmission. Together, our observations point to a greater complexity than previously recognized for glutamatergic neurotransmission, based on the joint versus independent actions of NO relative to NMDA receptors at pre- versus postsynaptic sites.

Bisphenolic compounds that enhance cell cation transport are found in commercial phenol red.

We have isolated two bisphenolic compounds (4 and 5) that have a marked effect on K+ and Na+ concentrations in human cells from commercial preparations of the pH indicator dye phenol red (phenolsulfonphthalein). We used a bioassay to identify active chromatographic fractions from the lipophilic impurities present in phenol red, and we determined the structure of two active components (4 and 5) by 1H and 13C NMR and mass spectrometry. When added to human fibroblasts in serum-free medium, the bisphenol fluorene derivative 9,9-bis(4'-hydroxyphenyl)-3-hydroxyfluorene (5) produced a rapid loss of K+ and a gain of Na+, at low concentrations, with an EC50 between 30 and 60 ng/mL (80-160 nM). The 2- and 4-hydroxy isomers of the fluorene 5 (i.e., compounds 6 and 7), prepared by synthesis, had similar activity, although compound 6 was somewhat less potent. The bisphenol xanthene derivative 9,9-bis(4'-hydroxyphenyl)xanthene (4) elicited a similar biological response but was less potent than 5-7; it also had a strong effect on cell adhesion, causing release of cells from the plastic substrate at concentrations as low as 2-5 microg/mL (5.5-14 microM). The structures of xanthene (4) and fluorene (5) bisphenols have been confirmed by synthesis from xanthone and hydroxyfluorenone, respectively, by Friedel-Crafts alkylation with phenol. In the latter case, the desired 3-hydroxyfluorene isomer was formed in situ by rearrangement of the 1-hydroxy isomer.

Long-term use of nonsteroidal antiinflammatory drugs and other chemopreventors and risk of subsequent colorectal neoplasia.

Our objective was to study the relationship between dispensed aspirin, nonaspirin nonsteroidal antiinflammatory drugs (NSAIDs), steroidal antiinflammatory drugs (SAIDs), acetaminophen, calcium, psyllium, and multivitamin preparations and the risk for subsequent colorectal adenoma and adenocarcinoma. The design was a case-control study. The patient population was from a large municipal teaching hospital in Atlanta, Georgia. In logistic regression models, the risk of colorectal adenoma or adenocarcinoma decreased in the first two years of continuous NSAID use in a linear, time-dependent manner. The risk of colorectal neoplasia after two years of continuous NSAID use was reduced significantly (P < 0.01) as compared to nonusers. Risk reduction appeared greater for adenocarcinoma than adenoma. The use of SAIDs, calcium, multivitamins, and psyllium, as prescribed to our patient population during the mean six-year study period, conferred no measurable risk reduction. These results suggest that in prospective chemoprevention trials, a significant risk reduction can be expected after only two years of aspirin use, in doses similar to those recommended for the prevention of cardiovascular disease, or nonaspirin NSAIDs [correction of nonaspirin. NSAIDs], in doses commonly prescribed for the management of musculoskeletal pain. The results also imply that any short-term reduction in the incidence of colorectal adenoma detected in a phase II trial would underestimate the chemopreventive effect of NSAIDs on the risk of adenocarcinoma.

Mutations in the BRCA1 gene in families with early-onset breast and ovarian cancer.

We analysed 50 probands with a family history of breast and/or ovarian cancer for germline mutations in the coding region of the BRCA1 candidate gene, using single-strand conformation polymorphism (SSCP) analysis on PCR-amplified genomic DNA. A total of eight putative disease-causing alterations were identified: four of these are frameshifts and two are nonsense mutations. In addition, we found two missense mutations, one of which changes the final cysteine of the BRCA1 zinc finger motif to glycine. These data are consistent with a tumour suppressor model, and support the notion that this candidate gene is in fact BRCA1. The heterogeneity of mutations, coupled with the large size of the gene, indicates that clinical application of BRCA1 mutation testing will be technically challenging.

Columnar activity regulates astrocytic beta-adrenergic receptor-like immunoreactivity in V1 of adult monkeys.

Recent results indicate that astrocytic beta-adrenergic receptors (beta AR) participate in noradrenergic modulation of synaptic activity. In this study, we sought to examine whether neural activity can, in turn, regulate astrocytic beta AR. To address this question, an antiserum that recognizes beta-adrenergic receptors (beta AR) specifically in astrocytes was used to assess the distribution of the receptors across ocular dominance columns in V1 of two monocular and four visually intact adult monkeys. Cytochrome oxidase histochemistry (CO) was used to identify the position of the cortical laminae and of the ocular dominance columns receiving visual inputs from the intact and enucleated eyes. This stain revealed the expected pattern within V1 of monocular monkeys--i.e. darker and lighter bands of equal widths (ca. 500 microns) spanning laminae 4-6, each associated with larger and smaller blobs, respectively, in lamina 2/3. Alignment of CO sections with adjacent sections stained for astrocytic beta AR by the immunoperoxidase method revealed intense beta AR-like immunoreactivity (beta AR-li) in the superficial laminae, a slightly weaker staining in the infragranular laminae and weakest staining in lamina 4C. Within lamina 4C, a prominent striped pattern was evident. The darker bands of the stripe closely matched widths and positions of the lighter CO columns associated with the enucleated eye. On the other hand, immunocytochemical staining for the astrocytic intermediate filament protein, GFAP, within V1 of monocular monkeys revealed no inter-columnar difference in the density of astrocytic cell bodies or processes. Nissl stain also revealed no overt inter-columnar differences in cell density.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitric oxide synthase in the visual cortex of monocular monkeys as revealed by light and electron microscopic immunocytochemistry.

Recent results indicate that nitric oxide (NO) can play an important role in neuronal excitability by modifying the strength of activated synapses and regulating local cerebral blood flow. We sought to determine whether the level of NO synthase (NOS) could, in turn, also be regulated by neural activity. Results using a polyclonal anti-NOS antibody showed that, in cortical area V1 of monocular monkeys, NOS-immunoreactivity is diminished in lamina 4C neuropil of the deprived ocular dominance columns relative to the immediately adjacent non-deprived columns. Closer examination of lamina 4C indicated that the intercolumnar difference in NOS-immunoreactivity does not reflect differences in the distribution of NOS-labeled perikarya, since relatively few neurons were immunoreactive for NOS in lamina 4C of either monocular or normal binocular monkeys. Electron microscopy revealed that the majority (> 80%) of NOS-immunoreactive profiles in lamina 4C are axon terminals. NOS-immunoreactive spines and dendritic shafts also are present but these are more prevalent in the superficial laminae. In order to determine whether the intercolumnar differences in lamina 4C neuropil correspond to altered densities of NOS cells in the superficial laminae, we performed a series of quantitative analyses. In the superficial laminae, NOS-cells occur as two distinguishable classes: a few that are large and intensely NOS-immunoreactive and many more (ca. 24-fold) that are small and lightly immunoreactive. Analysis of the distribution of 559 small and 105 large NOS-immunoreactive cells within 40-microns-thick tangential sections spanning laminae 2-3 showed that the number of cells (large and small together) associated with each blob is approximately 14 for both deprived (lighter) and non-deprived (darker) blobs. These cells are distributed evenly from the center to periphery of columns. Analysis of the distribution of NOS-cells in the infragranular laminae also did not reveal any columnar differences. These observations suggest that local neural activity may be coupled to NO release via alteration of NOS protein levels specifically within distal axonal processes of neurons. This mechanism could operate in conjunction with the more instantaneous catalytic activation of NOS. Ultrastructural analyses further suggest that NO may act as an anterograde and retrograde messenger arising from terminals in addition to its proposed role as a retrograde messenger arising from dendrites.

An impurity in phenol red opens an ion channel in cultured human cells.

Human fibroblast, bladder carcinoma, and breast carcinoma cells in commercial serum-free media or balanced salt solutions rapidly lose K+ and gain Na+. This rapid K+ loss is caused by one or more impurities in phenol red. Adding serum or albumin to media or to balanced salts prevents K+ loss. Quinine also prevents part of this loss in fibroblasts and breast carcinoma cells, suggesting that the impurity acts on an ion channel.