Deeper may not be better: relationship between catheter dysfunction and location of the catheter tip in right-sided tunnelled haemodialysis catheters.

AIM: To examine the relationship between catheter tip location and catheter dysfunction in the context of tunnelled central venous catheters (CVCs) for haemodialysis. MATERIALS AND METHODS: This was a retrospective study of 993 haemodialysis patients who underwent insertion of tunnelled CVCs of step-tip design via the right internal jugular vein (IJV). Based on intra-procedural radiographs, the catheter tip was characterised as being in the superior vena cava (SVC), cavo-atrial junction (CAJ), or deep right atrium (DRA). Patients were tracked for 90 days post-procedure for complications resulting in catheter replacement, and these were compared between cohorts. Statistical analysis was performed with Pearson's chi-square and Fisher's exact tests for categorical variables and two-sample t-test and one-way analysis of variance (ANOVA) for continuous variables. RESULTS: Ninety-five patients (9.6%) experienced catheter dysfunction necessitating replacement within 90 days of insertion. Tip location in SVC was associated with lower occurrence of catheter dysfunction (1.9%) as compared with the CAJ (8%) and DRA (11%; p=0.049). Catheter replacement due to other complications (catheter-associated bacteraemia, cuff dislodgement, exit-site infection, external catheter damage) showed no statistically significant relation to location of the CVC tip. CONCLUSION: When utilising tunnelled CVCs with a step-tip design inserted via the right IJV, location of the catheter tip in the SVC is associated with reduced occurrence of catheter dysfunction as compared to either the CAJ or DRA.

Synergistic Functions of Enzymes Bound to Semiconducting Layers.

Synthesis and cooperative functions of hybrid materials composed of enzyme and semiconducting layers are described in this chapter. The hybrids were produced via a simple physical interaction between the components, that is, electrostatic interaction in an aqueous solution. To form interstratifying enzymes in the galleries, solution pH, which is a key parameter to decide surface potential, should be adjusted appropriately. In other words, enzymes should have an opposite charge when compared to that of the layers at an identical pH. Even though the intercalation slightly reduced enzymatic activity as compared to those of the free enzymes, stability under cruel conditions was drastically improved due to screening effect of semiconducting layers from extrinsic stimuli. In addition, photochemical control of redox enzymes sandwiched between semiconducting layers was accomplished. Light irradiation of the hybrids induced band gap excitation of the layers, and holes produced in the valence band activated the enzymes. It was revealed that the semiconducting layers with magnetic elements might be useful to magnetic application (separation) of enzymes as similar to conventional magnetic beads.

A fluorescent probe for monitoring nitric oxide production using a novel detection concept.

A fluorescent probe using a novel 'spin exchange' concept was developed for monitoring nitric oxide (NO) production. The probe is composed of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) labeled with acridine and N-dithiocarboxysarcosine (DTCS)-Fe(II) complex. When the non-fluorescent acridine-TEMPO was incubated with DTCS-Fe(II) complex in buffer solution, the nitroxide radical in the acridine-TEMPO interacted with the Fe(II) through a redox interaction. This interaction recovered the fluorescence based on the acridine moiety. The addition of an NO-releasing reagent caused a fluorescent decrease of the probe due to the irreversible binding of NO to the Fe(II), and the amount of the fluorescent decrease strictly corresponded to that of released NO. Using this probe, less than 100 nM of NO can be detected. This probe system is not only useful for monitoring direct production of NO in an aqueous solution, but is also interesting as a basic concept by which to construct new types of NO fluorescent probes.

A new strategy for the design of molecular probes for investigating endogenous nitric oxide using an EPR or fluorescent technique.

A development of a new probe for NO, a molecule of profound biophysiological importance, based on the concept of "spin exchange" is described. This probe, based on the detection of a released TEMPOL radical, offers detection by EPR to 10 nm.

The glycaemic index of potatoes: the effect of variety, cooking method and maturity.

OBJECTIVE: The aim of this study was to determine the impact of variety, cooking method and maturity on the GI of potatoes, it was hypothesised that new potatoes may have a relatively lower GI. DESIGN AND SUBJECTS: Ten healthy volunteers were recruited as subjects through advertising on the campus of the University of Sydney. Equal (50 g) carbohydrate portions of eight potato meals (three varieties, four cooking methods, two states of maturity) and two reference white bread meals were fed in random order to each of the subjects over a period of 10 weeks. Capillary blood samples were taken in the fasting state and then at 15, 30, 45, 60, 90 and 120 min from the start of each meal. Samples were analysed for plasma glucose concentrations and incremental areas under plasma glucose curves were calculated. The GI of the potato was calculated as the AUC of the potato expressed as a percentage of the individual's average AUC of the white bread. This was then multiplied by 0.7 to index the GI to glucose as the reference food. RESULTS: GI values (mean +/- s.e.m.) ranged from 65+/-9 (canned new potatoes) to 10+/-15 (boiled Desiree potatoes), glucose = 100. No significant difference was found among the three varieties of potato tested (P = 0.38) or among the four different cooking methods (P = 0.55). The GI values of the canned new potato and boiled Desiree potato were significantly different (P = 0.047). The average size of the tuber was found to correlate with the GI (r = 0.83, P<0.05). CONCLUSIONS: Potatoes, regardless of variety, cooking method and maturity, have exceptionally high GI values. New potatoes have relatively lower GI values which is attributed to differences in starch structure.

Immunologic response of adenoidal lymphocytes to respiratory syncytial virus.

Adenoidal lymphocytes obtained from 43 subjects with serum antibodies to respiratory syncytial virus (RSV) were established in culture in vitro and analyzed for immunoglobulin (Ig) and RSV-specific antibody synthesis. Spontaneous synthesis of Ig was consistently observed in culture supernatants. The ratios of IgA to IgG and IgM to IgG in adenoidal lymphocyte culture supernatant were higher than in serum. In cell cultures stimulated with RSV or pokeweed mitogen, RSV antibody activity was detected in 25 of 43 (58.1%) for IgG, 5 of 43 (11.6%) for IgA, and 4 of 43 (9.3%) for IgM. Also, RSV-specific IgG was detected in some supernatants from unstimulated cultures. In seven cases the cultures of autologous tonsillar lymphocytes were also investigated. Autologous organs exhibited similar polyclonal Ig production and RSV-specific antibody synthesis. These observations demonstrate that both adenoids and palatine tonsils are continuously engaged in synthesis of local antibodies to viral pathogens available to the nasopharynx and respiratory mucosa.

Distribution characteristics of immunoglobulin-secreting cells in adenoids. Relationship to age and disease.

Forty-four adenoids and 52 palatine tonsils from 71 children and adolescents (age 3-21 years) undergoing surgery because of adenoidal hypertrophy or recurrent tonsillitis were examined for the presence of immunoglobulin-secreting cells (ISC) employing an enzyme-linked immunospot assay (ELISPOT). ISC constituted less than 2% of the mononuclear cell population. Adenoids contained IgG, IgA, and IgM ISC in significantly lower numbers than palatine tonsils. The predominant isotype of the ISC was IgG, in adenoids accounting for 62% of the ISC and in palatine tonsils for 73%. The relative numbers for IgA and IgM ISC were similar. A significant correlation existed between autologous adenoids and palatine tonsils for the numbers of IgA and IgM ISC, but not for the numbers of IgG cells. These observations suggest that, adenoid and palatine tonsils display similar immunoglobulin distribution patterns within a single individual. However, individuals with hypertrophied adenoids exhibited a numeric decrease in IgG ISC with increasing age (P less than 0.01). Both lymphoid tissues may be involved in mucosal immune defense.

Metastases to the Rouviere nodes and headache.

This paper presents two cases of Rouviere node metastasis in carcinoma of the hypopharynx as confirmed by gallium scintigraphy. Invasion of the Rouviere nodes was clarified within six months of the onset of symptoms in both cases. One patient eventually died of intracranial cancerous invasion and the other remains in the terminal stage of cancer with multiple bone metastases. It was hitherto believed that metastases to the Rouviere nodes were extremely difficult to diagnose in the early stages. However, it is now apparent that the neurological signs and symptoms which commonly appear in patients with cancerous invasion of the jugular foramen syndrome facilitate early diagnosis of the disease, the most common symptom being a headache.

The action of nerveside, a peptide extracted from brain, on myenteric ganglia in Auerbach's plexus.

1. In the rabbit jejunum nerveside causes alternating contractions of the longitudinal and circular muscles, which are similar to the peristaltic reflex produced by distension of the gut. These effects are abolished by dibucaine (Nupercaine) and tetrodotoxin. The site of action is located in Auerbach's plexus.2. Circular muscle contractions due to nerveside are blocked by hexamethonium, nicotine, morphine, atropine and hyoscine. There is no circular response to nerveside after removal of Auerbach's plexus. It is suggested that nerveside acts by stimulating presynaptic nerve terminals which are cholinergic and that the circular muscle is innervated by cholinergic nerve fibres.3. Longitudinal muscle contractions due to nerveside are not affected by hexamethonium but can be blocked by paralysis of myenteric ganglia with nicotine. They are not abolished by morphine or by cholinolytic drugs. It is suggested that nerveside acts by stimulating either receptors insensitive to acetylcholine in ganglion cells or non-cholinergic presynaptic nerve terminals. It is further suggested that the longitudinal muscle of the rabbit gut is supplied by non-cholinergic as well as cholinergic nerve fibres.