Comparison of silicon photonic crystal resonator designs for optical trapping of nanomaterials

The use of silicon photonic devices for optical manipulation has recently enabled the direct handling of objects like nucleic acids and nanoparticles that are much smaller than could previously be trapped using traditional laser tweezers. The ability to manipulate even smaller matter however requires the development of photonic structures with even stronger trapping potentials. In this work we investigate theoretically several photonic crystal resonator designs and characterize the achievable trapping stiffness and trapping potential depth (sometimes referred to as the trapping stability). Two effects are shown to increase these trapping parameters: field enhancement in the resonator and strong field containment. We find trapping stiffness as high as 22.3 pN nm(-1) for 100 nm polystyrene beads as well as potential depth of 51,000 k(B)T at T = 300 K, for one Watt of power input to the bus waveguide. Under the same conditions for 70 nm polystyrene beads, we find a stiffness of 69 pN nm(-1) and a potential depth of 177,000 k(B)T. Our calculations suggest that with input power of 10 mW we could trap particles as small as 7.7 nm diameter with a trapping depth of 500 k(B)T. We expect these traps to eventually enable the manipulation of small matter such as single proteins, carbon nanotubes and metallic nanoparticles.

Transient simulation of last deglaciation with a new mechanism for Bolling-Allerod warming

We conducted the first synchronously coupled atmosphere-ocean general circulation model simulation from the Last Glacial Maximum to the Bølling-Allerød (BA) warming. Our model reproduces several major features of the deglacial climate evolution, suggesting a good agreement in climate sensitivity between the model and observations. In particular, our model simulates the abrupt BA warming as a transient response of the Atlantic meridional overturning circulation (AMOC) to a sudden termination of freshwater discharge to the North Atlantic before the BA. In contrast to previous mechanisms that invoke AMOC multiple equilibrium and Southern Hemisphere climate forcing, we propose that the BA transition is caused by the superposition of climatic responses to the transient CO(2) forcing, the AMOC recovery from Heinrich Event 1, and an AMOC overshoot.

Silent subtype 3 pituitary adenoma: a clinicopathologic analysis of the Mayo Clinic experience

BACKGROUND

Macroadenomas represent 50% of pituitary tumours and are often (30%) nonfunctioning. Their immunophenotype suggests differentiation toward a specific pituitary cell line. A substantial proportion of tumours with particularly aggressive behaviour are so called 'silent subtype 3 adenoma'. Its diagnosis requires ultrastructural confirmation. Although once included among silent corticotroph adenomas, this aggressive, morphologically distinctive tumour is now recognized as a major form of plurihormonal adenoma and, in fact, some patients might present with clinical hormonal excess. The cytogenesis and pathobiology of silent subtype 3 adenomas is unsettled.

OBJECTIVE

We undertook a systematic clinicopathologic examination of the Mayo Clinic experience with this poorly understood tumour.

DESIGN

This retrospective, single institution study found 27 confirmed examples of silent subtype 3 adenoma, a frequency of 0.9% of adenomas. Despite histologic and immunophenotypic variation, their ultrastructural features were diagnostic and the sole basis for case inclusion.

RESULTS

The study group was comprised of 16 men (59%) and 11 women (41%); two patients (7%) had definitive diagnosis of multiple endocrine neoplasia type 1 (MEN1). Three tumours (11%) were discovered incidentally. Nine patients each (38%) presented with headaches or visual field loss. Endocrine hyperfunction was noted in eight cases (30%), including GH excess in five (19%) and clinically significant PRL elevation in three (11%). Hypogonadism was noted in 17 cases (63%) and growth arrest in one (4%). All tumours were macroadenomas; 16 (60%) showed radiographic evidence of invasion. Most tumours were plurihormonal, featuring immunoreactivity for PRL (17), GH (15), TSH (16) or ACTH (3); only one lesion was immunonegative. Although a gross total resection was achieved in 19 cases (70%), re-operation for recurrence(s) was required in seven of these (37%). Follow-up (mean, 69 months) showed a high (59%) rate of persistent or recurrent of tumour. Overall, 14 patients (54%) underwent radiotherapy after surgical treatment: three patients (12%) for substantial residual tumour, eight (31%) as adjuvant therapy and three (12%) for tumour regrowth.

CONCLUSION

Silent subtype 3 adenoma, a plurihormonal tumour, is rare and aggressive in nature. This adenoma must be considered in the differential of often clinically nonfunctioning but plurihormonal adenomas featuring variable cytologic atypia. Electron microscopy is required for confirmation of the diagnosis. The cytogenesis of silent subtype 3 adenoma remains unsettled.

Pratylenchus neglectus, P. thornei, and Paratylenchus hamatus Nematodes Causing Yield Reduction to Dryland Peas and Lentils in Idaho

In June 2006, stunted and chlorotic plants were observed in large patches in two 40.5-ha fields of dryland peas (Pisum sativum) in Latah County, Idaho, which resulted in 90 and 75% crop loss. In the same region, a 121.4-ha field of dryland lentils (Lens culinaris) also had plants showing poor growth, wilting, and yellowing in large patches, which resulted in 40% crop loss. Two species of lesion nematodes (Pratylenchus neglectus and P. thornei) and one species of pin nematode (Paratylenchus hamatus) were extracted from rhizosphere soil and the roots of symptomatic plants from these fields. In a subsequent survey of seven dryland pea fields, under cv. Columbian, in Latah and Nez Perce counties and one dryland pea field, under cv. Small Sieve, in Latah County, plant samples had means of 551 and 2,178 mixed species of lesion nematodes per gram of dry root, respectively. Plant samples from 12 lentil fields in Latah County, six planted with cv. Red Chief and six with cv. Pardina, had means of 279 and 987 mixed species of lesion nematodes per gram of dry root, respectively. Soil samples from the same fields had a mean of 628 and 671 pin nematodes, Paratylenchus hamatus, per 250 cm³ soil for Red Chief and Pardina, respectively. Lentils cv. Pardina and peas cv. Columbian were planted separately in six pots, five seeds per pot containing 250 g of infested soil brought from the field to the greenhouse. Fumigated sandy loam soil was used as control. These assays were repeated three times. In addition, peas and lentils were planted to pots infested singly with each of the three nematode species. For this assay, nematodes were extracted from field soil, surface sterilized, and used to infest 250 g of fumigated sandy loam soil at two nematodes per gram of soil. Six plants per nematode species and an uninoculated control were used in the greenhouse assays, which were repeated three times. Nematodes in all of the assays reduced plant growth in comparison with controls; an average of 50 to 70% reduction in plant height was noted. The lesion nematode populations increased in all pots. The greenhouse assays verified the negative impact of these nematodes on growth of dryland peas cvs. Columbian and Small Sieve and lentils cvs. Red Chief and Pardina. P. neglectus, P. thornei, and Paratylenchus spp. previously have been reported from the semi-arid Pacific Northwest (1). However, to our knowledge, this is the first report attributing plant growth and yield reduction of certain cultivars of lentils and peas to these two species of lesion nematodes and pin nematodes, identified to species level as Paratylenchus hamatus. Reference: (1) R. W. Smiley et al. J. Nematol. 36:54, 2004.

Structured assessment of current mental state in clinical practice: an international study of the reliability and validity of the Current Psychiatric State interview, CPS-50

OBJECTIVE

To develop a reliable standardized assessment of psychiatric symptoms for use in clinical practice.

METHOD

A 50-item interview, the Current Psychiatric State 50 (CPS-50), was used to assess 237 patients with a range of psychiatric diagnoses. Ratings were made by interviewers after a 2-day training. Comparisons of inter-rater reliability on each item and on eight clinical subscales were made across four international centres and between psychiatrists and non-psychiatrists. A principal components analysis was used to validate these clinical scales.

RESULTS

Acceptable inter-rater reliability (intra-class coefficient > 0.80) was found for 46 of the 50 items, and for all eight subscales. There was no difference between centres or between psychiatrists and non-psychiatrists. The principal components analysis factors were similar to the clinical scales.

CONCLUSION

The CPS-50 is a reliable standardized assessment of current mental status that can be used in clinical practice by all mental health professionals after brief training.

271INFLUENCE OF ARGININE-GLYCINE-ASPARTIC ACID (RGD) IN BOVINE SPERM-EGG BINDING, AND FERTILIZATION IN VITRO

Osteopontin (OPN), a secretory RGD-containing phosphoprotein, has been identified in cow oviductal ephitelium and fluid, but its role in fertilization is unclear. RGD peptide is capable of blocking fertilization, inducing intracellular Ca2+ transients, and initiating parthenogenetic development when present during bovine fertilization in vitro.This study was conducted to determine whether in vitro sperm binding to the zona pellucida (ZP) and fertilization of bovine oocytes were affected by treating the sperm or oocytes with RGD (arginine–glycine–aspartic acid, a sequence recognized by integrins) or non-RGD-containing peptides. In vitro matured oocytes were incubated (39°C, 5% CO2 in air) for 2 hours in fertilization medium with: (1) no peptides;; (2) 50μgmL−1 RGD (Calbiochem®, San Diego, CA, USA); (3) 1000μgmL−1; (4) 50μgmL−1 non-RGD (Calbiochem®); (5) 1000μgmL−1 non-RGD. The bovine sperm from two differents bulle was collected by artificial vagina, pooled, washed twice with MTM at 500g for 10min and incubated (39°C, 5% CO2 in air) for two h at 5×107 concentration in MTM with: (6) no peptides;; (7) 50μgmL−1 RGD;; (8) 1000μgmL−1; (9) 50μgmL−1 non-RGD; (10) 1000μgmL−1 non-RGD. Following incubation, treated and untreated oocytes were washed and inseminated with 1×105 treated or untreated fresh spermatozoa per 10 oocytes;; after the sperm were recovered from a Percoll gradient (45%/90%). After 18–20h, oocytes were removed from co-culture, and washed in TL-HEPES. Oocytes used to assess sperm binding were stained with Hoescht 33342, and the number of sperm bound per ZP counted. The remaining oocytes were fixed in acid alcohol, stained with 1% acetato-orcein and observed for the presence of pronuclei. For the five replicates, 100–120 oocytes were used for fertilization and 150–170 oocytes were used for sperm-egg binding assays. Data were analized by SAS. Treatment of sperm or oocytes with the RGD peptide significantly decreased (P<0.05) fertilization compared to the non-treated controls or those treated with non-RGD peptides: (1) 80%±3.0; (2) 42%±3.0; (3) 30.2%±3.0; (4) 78.5%±3.0; (5) 79.1%±3.0; (6) 78.9%±3.0; (7) 41.3%±3.0; (8) 29.1%±3.0; (9) 79.2%±3.0; (10) 80.2%±3.0. More sperm bound to the ZP of untreated or non-RGD-treated oocytes or sperm than those incubated with the RGD peptide: (1) 71.2±4.1; (2) 33.2±4.2; (3) 24.2±4.1; (4) 69.5±4.1; (5) 70.2±4.2; (6) 71.9±4.2; (7) 29.8±4.2; (8) 19.8±4.2; (9) 68.9±4.2; (10) 70.6±4.2. These studies demonstrated that incubation of bovine oocytes or spermatozoa with a RGD peptide inhibits sperm-egg binding and fertilization in vitro. These findings support the notion that the role of osteopontin in bovine fertilization may involve inteaction with integrins via its RGD sequence.

Numerical Simulations of Capillary-Driven Flows in Nonuniform Cross-Sectional Capillaries

In this study the wetting behavior of converging-diverging and diverging-converging capillaries is investigated numerically using an in-house written, finite-element code. An interface tracking procedure based on the predicted change in the total liquid volume, to update the interface location, and Cox's formulation, to determine the dynamic contact angle and the interface shape, is proposed and used. Flow simulations revealed that both converging-diverging and diverging-converging capillaries exhibit significantly slower wetting behavior than straight capillaries and that any deviation in the capillary diameter necessarily tends to slow the overall wetting speed. This behavior was attributed to local regions of very low capillary pressure and high viscous retardation force when the capillary diameter at the interface was significantly larger than the capillary diameter over the upstream fluid. Though the local wetting velocities were different, when equivalent capillaries were compared it was found that both converging-diverging and diverging-converging capillaries had the same total fill time independent of the number of irregular regions, suggesting that the simple model is sufficient for predicting the overall effect. The influence of surface tension and contact angle on the total wetting time was found to be similar for both straight and irregularly shaped capillaries.

Automated detection of the G20210A prothrombin mutation using the LCx microparticle enzyme immunoassay

BACKGROUND

The prothrombin mutation, a G/A transition at position 20210 in the 3' untranslated region of the prothrombin gene, is associated with an increased risk of deep venous thrombosis and obstetrical complications. Several methods have been developed to detect the mutation; however, given the increased demand for this test in risk factor assessment, the development of simple and efficient screening methods has become necessary.

METHODS

We have used a rapid, sensitive, and precise method developed by Abbott Laboratories to detect the prothrombin mutation. The method employs a polymerase chain reaction (PCR) amplification and the Abbot LCx microparticle enzyme immunoassay (MEIA) for detection. This method is able to detect and identify both homozygous and heterozygous genotypes.

RESULTS

Two hundred ninety-six patients with a history of deep venous thrombosis, pulmonary embolism, preeclampsia, or cardiovascular disease and 163 control patients were included in this study. The prevalence of the mutation was 5.74% in the high-risk group and 3.06% in the control group. There was complete agreement between the results from the MEIA detection with those obtained using other detection methodologies, namely standard PCR and restriction fragment length polymorphism (RFLP) analysis.

CONCLUSIONS

The MEIA detection method of the prothrombin mutation represents a simple, fast, and reliable alternative to standard methods of detection and is well suited for use in routine clinical laboratories. The results of our study confirm others' studies showing a greater incidence of G20210A prothrombin gene mutation in patients with an increased risk of venous thrombosis and pulmonary embolism as well as patients with cardiovascular disease and pregnant women with preeclampsia. It reinforces the necessity of including the screening for prothrombin mutation in populations at risk.

Benign paragangliomas: clinical presentation and treatment outcomes in 236 patients

Paragangliomas are rare tumors that arise from extraadrenal chromaffin cells. We examined the clinical characteristics, location, treatment, and outcome of 236 patients (141 females, 60%) with 297 benign paragangliomas evaluated at the Mayo Clinic during 1978-1998. The mean age (+/-SD) at diagnosis was 47 +/- 16 yr. Of the 297 paragangliomas, 205 were in the head and neck region, and 92 were below the neck. Paragangliomas were discovered and diagnosed incidentally on imaging studies in 9% of patients. Biochemical screening was performed in 128 patients; 40 patients (17% of the total and 31% of those screened) had hyperfunctional tumors. Of the 40 patients with tumoral catecholamine excess, 38 had documented hypertension. In patients identified with catecholamine-secreting paragangliomas, the sensitivities achieved by measurements in the 24-h urine collection were 74% for total metanephrines, 84% for norepinephrine, 18% for dopamine, and 14% for epinephrine. Multiple imaging modalities were used for tumor localization. The false negative rates were 0% for magnetic resonance imaging, 5.8% for computed tomography, 3.4% for angiography, 10.7% for ultrasonography, and 39% for radioactive iodine-labeled metaiodobenzylguanidine scintigraphy. Of 192 patients (81.4%) with follow-up data (mean, 43.9 months; range, 0.5-240), operative cure was achieved in 133 (69%). Of the 59 patients without cure, 23 had persistent disease, 5 had recurrent disease, 16 had multiple persistent synchronous tumors, and 15 subsequently developed metachronous tumors. In conclusion, most paragangliomas are nonhypersecretory and located in the head and neck region. Magnetic resonance imaging was associated with the lowest false negative rate, and metaiodobenzylguanidine was the least sensitive imaging study. A significant proportion of patients (31%) has persistent or recurrent disease, and long-term follow-up is important.

A new ultrasensitive assay for quantitation of HIV-1 RNA in plasma

Nucleic acid-based diagnostic assays for the quantitation of plasma HIV-1 RNA levels are used to monitor disease progression and the response of patients to antiretroviral drug therapy. The LCx HIV RNA Quantitative Assay (Abbott Laboratories, North Chicago, IL) is an assay for the quantitation of HIV type 1 RNA in plasma that uses competitive reverse transcription PCR (RT-PCR) followed by Microparticle Enzyme Immunoassay, and includes an internal control for inhibition and RNA recovery, that is taken through the entire sample preparation procedure. The performance of the assay was assessed for 1 and 0.2 ml sample volumes. For a 1 ml sample volume, the lower limit of detection was found to be 50 copies/ml with a linear range from 50 to 1 million copies/ml. For a 0.2 ml sample volume, the lower limit of detection was found to be 178 copies/ml with a linear range from 178 to 5 million copies/ml. The assay is able to detect and quantitate HIV subtypes A-G and group O. LCx HIV RNA assay quantitation results are highly correlated to the standard and ultrasensitive Amplicor HIV-1 Monitor assay (Roche Molecular Systems) quantitation results. Assay performance is consistent with the use of this test for routine quantitation of HIV-1 RNA in plasma.

On the symmetry of limb deficiencies among children with multiple congenital anomalies

In humans, unpaired organs are placed in a highly ordered pattern along the left-right axis. As indicated by animal studies, a cascade of signaling molecules establish left-right asymmetry in the developing embryo. Some of the same genes are involved also in limb patterning. To provide a better insight into the connection between these processes in humans, we analysed the symmetry of limb deficiencies among infants with multiple congenital anomalies. The study was based on data collected by the International Clearinghouse for Birth Defects Monitoring Systems (ICBDMS). Registries of the ICBDMS provided information on infants who, in addition to a limb deficiency, also had at least one major congenital anomaly in other organ systems. We reviewed 815 such cases of which 149 cases (18.3 %) were syndromic and 666 (81.7 %) were nonsyndromic. The comparisons were made within the associated limb deficiencies, considering the information on symmetry, using a comparison group with malformations associated not involved in the index association. Among the non-syndromic cases, the left-right distribution of limb deficiencies did not differ appreciably between limb deficiency subtypes (e.g., preaxial, transverse, longitudinal). The left-right distribution of limb anomalies did not differ among most types of non-limb anomalies, though a predominance of left-sided limb deficiencies was observed in the presence of severe genital defects - odds ratio [OR], 2.6; 95 % CI, 1.1-6.4). Limb deficiencies (LDs) were more often unilateral than bilateral when accompanied by gastroschisis (OR, 0.1) or axial skeletal defects (OR, 0.5). On the contrary, LDs were more often bilateral than unilateral when associated with cleft lip with or without cleft palate (OR, 3.9) or micrognathia (OR, 2.6). Specifically, we found an association between bilateral preaxial deficiencies and cleft lip, bilateral amelia with gastroschisis and urinary tract anomalies, and bilateral transverse deficiencies and gastroschisis and axial skeleton defects. Of 149 syndromic cases, 62 (41.6 %) were diagnosed as trisomy 18. Out of the 30 cases of trisomy 18 with known laterality, 20 cases were bilateral. In the remainder the right and left sides were equally affected. Also, in most cases (74.4 %) only the upper limbs were involved. In conclusion the left-right distribution of limb deficiencies among some non-limb anomalies may suggest a relationship between the development of the limb and the left-right axis of the embryo.

An Improved Method of Determining the zeta-Potential and Surface Conductance

In the classical "slope-intercept" method of determining the zeta potential and the surface conductance, the relationship between DeltaP and E(s) is measured experimentally at a number of different channel sizes (e.g., the height of a slit channel, h). The parameter (epsilon(r)epsilon(0)DeltaP/µE(s)lambda(b)) is then plotted as a function of 1/h and linear regression is performed. The y-intercept of the regressed line is then related to the zeta-potential and its slope to the surface conductance. However, in this classical method, the electrical double layer effect or the electrokinetic effects on the liquid flow are not considered. Consequently, this technique is valid or accurate only when the following conditions are met: (1) relatively large channels are used; (2) the electrical double layer is sufficiently thin; and (3) the streaming potential is sufficiently small that the electroosmotic body force on the mobile ions in the double layer region can be ignored. In this paper a more general or improved slope-intercept method is developed to account for cases where the above three conditions are not met. Additionally a general least-squares analysis is described which accounts for uncertainty in the measured channel height as well as unequal variance in the streaming potential measurements. In this paper, both the classical and the improved slope-intercept techniques have been applied to streaming potential data measured with slit glass channels, ranging in height from 3 µm to 66 µm, for several aqueous electrolyte solutions. The comparison shows that the classical method will always overestimate both the zeta-potential and the surface conductance. Significant errors will occur when the classical method is applied to systems with small channel heights and low ionic concentrations. Furthermore, it is demonstrated that traditional regression techniques where the uncertainty is confined only to the dependent variable and each measurement is given equal weight may produce physically inconsistent results. Copyright 2000 Academic Press.

Xplore mRNA assays for the quantification of IL-1 beta and TNF-alpha mRNA in lipopolysaccharide-induced mouse macrophages

Because the accurate measurement of a number of cytokine mRNA transcripts provides valuable knowledge about cytokine gene regulation, we have developed the Xplore assay for the quantification of cytokine mRNA. This microplate-based assay is rapid (under four hours), quantitative over three orders of magnitude and carries no risk of false-positive values from contamination with amplified target. Here, we describe the use of Xplore assays to measure the steady-state mRNA levels of TNF-alpha and IL-1 beta produced by mouse WEHI and J774 macrophage-like cell lines.

Adrenocorticotropic hormone-dependent Cushing's syndrome: sensitivity and specificity of inferior petrosal sinus sampling

BACKGROUND AND PURPOSE

Determining the cause of Cushing's syndrome can be difficult. Bilateral inferior petrosal sinus (IPS) sampling after ovine corticotropin-releasing hormone (oCRH) stimulation is an established technique for the differentiation of pituitary from nonpituitary sources of adrenocorticotropic hormone (ACTH) production. The purpose of this study was to review our experience to determine the sensitivity and specificity of bilateral IPS sampling.

METHODS

Between January 1990 and February 1997, 92 patients underwent 94 IPS sampling procedures. Indications for these patients with Cushing's syndrome included no discrete lesion on MR images or CT scans, a discrete lesion present on images but equivocal peripheral ACTH sampling after oCRH stimulation, and persistent Cushing's syndrome after trans-sphenoidal surgery.

RESULTS

IPS sampling yielded six false-negative results and one false-positive result, manifesting an overall sensitivity of 92.2% and a specificity of 90.0% for detection of a pituitary source of ACTH after oCRH stimulation. Microadenoma lateralization by IPS sampling after oCRH stimulation agreed with the surgical location in 70.0% of the patients. The technical success rate of initial (presampling) bilateral IPS catheterization was 93.6%. Two serious complications occurred and consisted of a venous subarachnoid hemorrhage and a lower extremity deep venous thrombosis.

CONCLUSION

Bilateral IPS sampling after oCRH stimulation is helpful in the evaluation of ACTH-dependent Cushing's syndrome. False-negative results, however, suggest that the possibility of a pituitary source must still be considered when no response to oCRH is documented. Interpetrosal ACTH gradient alone is not sufficient to lateralize the tumor reliably.

Critical care bug team: a multidisciplinary team approach to reducing ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia rates in the medical-surgical intensive care unit first exceeded the 90th percentile in September 1997 and were significantly (P <.05) higher than National Nosocomial Infections Surveillance System pooled mean data. In January 1998, a multidisciplinary "Critical Care Bug Team" was developed by the Infection Control Committee to review 1997 National Nosocomial Infections Surveillance System data for four adult intensive care units in a 583-bed tertiary care hospital.

METHODS

Membership included clinical nurse specialists, a dietitian, a pharmacist, a respiratory therapist, an infection control professional, a research specialist, and a physician adviser. Having the team report directly to the hospital's Infection Control and Adult Critical Care Committees maximized support for recommendations and provided a direct link from patient care to hospital administration. By identifying issues, evaluating patient care processes, performing literature searches, and monitoring compliance, the team implemented numerous interventions, including policy and procedure changes, purchasing of equipment, and implementation of various education tools.

RESULTS

Each member of the Critical Care Bug Team contributed to a synergized effort that may have produced the desired outcome of decreasing ventilator-associated pneumonia rates. Except for August 1998, ventilator-associated pneumonia rates have been below the 75th percentile since May 1998.

CONCLUSION

This study illustrates the effectiveness of a multidisciplinary team approach devised to reduce and stabilize ventilator-associated pneumonia rates in a medical-surgical intensive care unit.

Lectin histochemical examination of rabbit bladder glycoproteins and characterization of a mucin isolated from the bladder mucosa

The glycocalyx of the mucosal surface of urinary bladder acts as an effective barrier against invasion by pathogenic microorganisms and injury from toxic substances in the urine. Defects in these bladder mucosal components could thus be important factors in the development of diseases such as interstitial cystitis and lower urinary tract infections. However, information on the nature of glycoconjugates of mammalian bladder mucosa is very limited. In this study, the glycoconjugates of rabbit bladder were examined histochemically using biotinylated lectins with specificities for a variety of carbohydrate moieties. Three [Artocarpus integrifolia (Jacalin), Datura stramonium (DSL), and Maackia amurensis II (MAL-II)] of the lectins bound predominantly to the luminal cell layer, with decreased binding to the basal layers of the epithelium. In contrast, Ricinus communis I and Sambucus nigra lectins did not bind to the cells in the epithelium but strongly interacted with the subepithelial layers, especially the lamina propria. The intensity of the staining by Jacalin and MAL-II was significantly reduced by prior treatment of the bladder sections with O-sialoglycoprotein endopeptidase, indicating that the ligands of these lectins are primarily mucin glycoproteins. In parallel biochemical studies, a high-molecular-weight glycoprotein with characteristics typical of epithelial mucins was purified from the mucosa of rabbit bladder explant cultures metabolically labeled with [(3)H]glucosamine. Quantitative analysis of the sialic acid, uronic acid, and hexosamine contents of delipidated rabbit bladder mucosa revealed a larger proportion of sialoglycoproteins compared with glycosaminoglycans. Taken together, the results of histochemical and biochemical analyses indicate that glycoproteins rather than glycosaminoglycans are the major components of the bladder epithelium, and that the former include a mucin.

Chronic intermittent stimulation of the thyroarytenoid muscle maintains dynamic control of glottal adduction

Patients with laryngeal motor control disorders need improved dynamic glottal closure for speech and swallowing. To evaluate the functional outcome of intermittent chronic thyroarytenoid muscle stimulation in an animal model, 6 canines were implanted with bilateral Medtronic Xtrel systems containing Peterson-type electrodes in the inferior and superior portions of the thyroarytenoid muscle. Stimulation was on one side only at 60 Hz, for 5 s on and 5 s off, over 8 h, 5 days per week, up to 8 months. Monthly videorecordings were done under anesthesia to measure the voltage threshold for detectable movement on each side, and vocal fold displacement and velocity during maximal stimulation of each side. Movement thresholds were lower in the inferior portion of the thyroarytenoid muscle (P </= 0.0005). Movement velocity was greater on the stimulated than on the nonstimulated side after 3 to 8 months (P = 0.039). No differences in the percentage distribution of different myosin heavy chain types were found between the stimulated and nonstimulated muscle samples. Sustained dynamic glottal adduction with no alteration in thyroarytenoid muscle function or fiber type was achieved with intermittent stimulation over 8 months. The results suggest that chronic intermittent thyroarytenoid stimulation has good potential for improving airway protection in dysphagia.