Treatment implications of a positive sentinel lymph node biopsy for patients with early-stage breast carcinoma

BACKGROUND. Sentinel lymph node (SLN) mapping and biopsy is emerging as an alternative to axillary lymph node dissection (ALND) in determining the lymph node status of patients with early-stage breast carcinoma. The hypothesis of the technique is that the SLN is the first lymph node in the regional lymphatic basin that drains the primary tumor. Non-SLN (NSLN) metastasis in the axilla is unlikely if the axillary SLN shows no tumor involvement, and, thus, further axillary interference may be avoided. However, the optimal treatment of the axilla in which an SLN metastasis is found requires ongoing evaluation. The objectives of this study were to evaluate the predictors for NSLN metastasis in the presence of a tumor-involved axillary SLN and to examine the treatment implications for patients with early-stage breast carcinoma. METHODS. Between June 1998 and May 2000, 167 patients participated in the pilot study of SLN mapping and biopsy at Westmead Hospital. SLNs were identified successfully and biopsied in 140 axillae. All study patients also underwent ALND. The incidence of NSLN metastasis in the 51 patients with a SLN metastasis was correlated with clinical and pathologic characteristics. RESULTS. Of 51 patients with a positive SLN, 24 patients (47%) had NSLN metastases. The primary tumor size was the only significant predictor for NSLN involvement. NSLN metastasis occurred in 25% of patients (95% confidence interval [95%CI], 10-47%) with a primary tumor size less than or equal to 20 mm and in 67% of patients (95%CI, 46-83%) with a primary tumor size > 20 mm (P = 0.005). The size of the SLN metastasis was not associated significantly with NSLN involvement. Three of 7 patients (43%) with an SLN micrometastasis (< 1 mm) had NSLN involvement compared with 38 of 44 patients (48%) with an SLN macrometastasis (greater than or equal to 1 mm). CONCLUSIONS. The current study did not identify a subgroup of SLN positive patients in whom the incidence of NSLN involvement was low enough to warrant no further axillary interference. At present, a full axillary dissection should be performed in patients with a positive SLN. (C) 2001 American Cancer Society.

Postural activity of the diaphragm is reduced in humans when respiratory demand increases

1. Respiratory activity of the diaphragm and other respiratory muscles is normally co-ordinated with their other functions, such as for postural control of the trunk when the limbs move. The integration may occur by summation of two inputs at the respiratory motoneurons. The present study investigated whether postural activity of the diaphragm changed when respiratory drive increased with hypercapnoea. 2. Electromyographic (EMG) recordings of the diaphragm and other trunk muscles were made with intramuscular electrodes in 13 healthy volunteers. Under control conditions and while breathing through increased dead-space,subjects made rapid repetitive arm movements to disturb the stability of the spine for four periods each lasting 10 s, separated by 50 s. 3. End-tidal CO2, and ventilation increased for the first 60-120 s of the trial then reached a plateau. During rapid arm movement at the start of dead-space breathing, diaphragm EMG became tonic with superimposed modulation at the frequencies of respiration and arm movement. However, when the arm was moved after 60 s of hypercapnoea, the tonic diaphragm EMG during expiration and the phasic activity with arm movement were reduced or absent. Similar changes occurred for the expiratory muscle transversus abdominis, but not for the erector spinae. The mean amplitude of intra-abdominal pressure and the phasic changes with arm movement were reduced after 60 s of hypercapnoea. 4. The present data suggest that increased central respiratory drive may attenuate the postural commands reaching motoneurons. This attenuation can affect the key inspiratory and expiratory muscles and is likely to be co-ordinated at a pre-motoneuronal site.

The effect of tidal volume and peep on CO2 and oxygenation during resuscitation of very premature lambs

Background: Over-ventilation causing low arterial carbon dioxide levels (PaCO2) has been associated with the development of neonatal chronic lung disease and adverse outcomes. This may occur very soon after birth. Aim: To investigate the effect on PaCO2 and oxygenation of very premature lambs resuscitated with different tidal volumes and PEEP. Methods: Anaesthetised lambs delivered at 126 days gestation were randomised to 15 min resuscitation with 3 regimes: (1) Laerdal resuscitation bag (B) with 100% oxygen and no PEEP, (2) fixed tidal volume (VT) of 5 mL/kg, or (3) VT of 10 mL/kg, both delivered with a Babylog 8000 ventilator in volume guarantee mode with 8 cm H2O PEEP and variable FiO2. Frequent blood gases were measured and VT, mean airway pressure (Paw), minute volume (MV), ventilation rate (VR), respiratory system compliance (Crs) and alveolar/arterial oxygen difference (AaDO2) were recorded. Results: Twenty lambs were studied. B (1) was associated with more variable VT and peak inspiratory pressures (PIP) compared to fixed tidal volumes (2 and 3). The lambs ventilated with 10 mL/kg were over-ventilated, those ventilated with 5 mL/kg were slightly under-ventilated. Those ventilated with the Laerdal bag had a mean VT of 7.5 mL/kg and were normocarbic. The different tidal volumes had little effect on oxygenation. PEEP improved oxygenation. The table shows the values at 15 minutes expressed as mean and SEM. TABLE. No caption av... TABLE. No caption av... Image Tools Conclusion: Very premature lambs can be effectively resuscitated from birth using volume guarantee ventilation. Within minutes of birth different tidal volumes had a large effect on PaCO2 and no effect on oxygenation. Studies are needed to determine the appropriate tidal volume for resuscitating very premature infants to maintain acceptable levels of PaCO2. © International Pediatrics Research Foundation, Inc. 2004. All Rights Reserved.

Quantum phase-space analysis of the pendular cavity

We perform a quantum-mechanical analysis of the pendular cavity, using the positive-P representation, showing that the quantum state of the moving mirror, a macroscopic object, has noticeable effects on the dynamics. This system has previously been proposed as a candidate for the quantum-limited measurement of small displacements of the mirror due to radiation pressure, for the production of states with entanglement between the mirror and the field, and even for superposition states of the mirror. However, when we treat the oscillating mirror quantum mechanically, we find that it always oscillates, has no stationary steady state, and exhibits uncertainties in position and momentum which are typically larger than the mean values. This means that previous linearized fluctuation analyses which have been used to predict these highly quantum states are of limited use. We find that the achievable accuracy in measurement is fat, worse than the standard quantum limit due to thermal noise, which, for typical experimental parameters, is overwhelming even at 2 mK

Antibacterial activity of bovine lactoferrin-derived peptides

Several peptides sharing high sequence homology with lactoferricin B (Lf-cin B) were generated from bovine lactoferrin (Lf) with recombinant chymosin. Two peptides were copurified. one identical to Lf-cin B and another differing from Lf-cin B by the inclusion of a C-terminal alanine (lactoferricin). Two other peptides were copurified from chymosin-hydrolyzed Lf. one differing from Lf-cin B by the inclusion of C-terminal alanyl-leucine and the other being a heterodimer linked by a disulfide bond, These peptides were isolated in a single step from chymosin-hydrolyzed Lf by membrane ton-exchange chromatography and were purified by reverse-phase high-pressure liquid chromatography (HPLC), They were characterized by. N-terminal Edman sequencing, mass spectrometry, and antibacterial activity determination, Pure lactoferricin, prepared from pepsin-hydrolyzed Lf, was purified by standard chromatography techniques, This peptide was analyzed against a number of gram-positive and gram-negative bacteria before and after reduction of its disulfide bond or cleavage after its single methionine residue and was found to inhibit the growth of all the test bacteria at a concentration of 8 mu M or less, Subfragments of lactoferricin were isolated from reduced and cleaved peptide by reverse-phase HPLC, Subfragment 1 (residues I to 10) was active against most of the test microorganisms at concentrations of 10 to 50 mu M. Subfragment 2 (residues 11 to 26) was active against only a few microorganisms at concentrations up to 100 mu M. These antibacterial studies indicate that the activity of lactoferricin Is mainly, but not wholly, due to its N-terminal region.

A review of health effects of aircraft noise

Social surveys have established dose-response relationships between aircraft noise and annoyance, with a number of psychological symptoms being positively related to annoyance. Evidence that exposure to aircraft noise is associated with higher psychiatric hospital admission rates is mixed. Some evidence exists of an association between aircraft noise exposure and use of psychotropic medications. People with a pre-existing psychological or psychiatric condition may be more susceptible to the effects of exposure to aircraft noise. Aircraft noise can produce effects on electroencephalogram sleep patterns and cause wakefulness and difficulty in sleeping. Attendances at general practitioners, self-reported health problems and use of medications, have been associated with exposure to aircraft noise, but some findings are inconsistent. Some association between aircraft noise exposure and elevated mean blood pressure has been observed in cross-sectional studies of schoolchildren, but with little confirmation from cohort studies. There is no convincing evidence to suggest that all-cause or cause-specific mortality is increased by exposure to aircraft noise. There is no strong evidence that aircraft noise has significant perinatal effects. Using the World Health Organization definition of health, which includes positive mental and social wellbeing, aircraft noise is responsible for considerable ill-health. However, population-based studies have not found strong evidence that people living near or under aircraft flight paths suffer higher rates of clinical morbidity or mortality as a consequence of exposure to aircraft noise. A dearth of high quality studies in this area precludes drawing substantive conclusions.

A mathematical model for Escherichia coli debris size reduction during high pressure homogenisation based on grinding theory

Experimental data for E. coli debris size reduction during high-pressure homogenisation at 55 MPa are presented. A mathematical model based on grinding theory is developed to describe the data. The model is based on first-order breakage and compensation conditions. It does not require any assumption of a specified distribution for debris size and can be used given information on the initial size distribution of whole cells and the disruption efficiency during homogenisation. The number of homogeniser passes is incorporated into the model and used to describe the size reduction of non-induced stationary and induced E. coil cells during homogenisation. Regressing the results to the model equations gave an excellent fit to experimental data ( > 98.7% of variance explained for both fermentations), confirming the model's potential for predicting size reduction during high-pressure homogenisation. This study provides a means to optimise both homogenisation and disc-stack centrifugation conditions for recombinant product recovery. (C) 1997 Elsevier Science Ltd.

Major histocompatibility complex (MHC) class II-positive dendritic cells in the rat iris - In situ development from MHC class II-negative precursors

Purpose. To examine the postnatal development of major histocompatibility complex (MHC) class II-positive dendritic cells (DC) in the iris of the normal rat eye. Methods. Single-and double-color immunomorphologic studies were performed on whole mounts prepared from rat iris taken at selected postnatal ages (2 to 3 days to 78 weeks). Immunopositive cells were enumerated, using a quantitative light microscope, and MHC class II expression on individual cells was assessed by microdensitometric analysis. Results. Major histocompatibility class II-positive DCs in the iris developed in an age-dependent manner and reached adult-equivalent density and structure at approximately 10 weeks of age, considerably later than previously described in other DC populations in the rat. In contrast, the anti-rat DC monoclonal antibody OX62 revealed a population of cells present at adult-equivalent levels as early as 3 weeks after birth. Dual-color immunostaining and microdensitometric analysis demonstrated that during postnatal growth, development of the network of MHC class II-positive DCs was a consequence of the progressive increase in expression of MHC class II antigen by OX62-positive cells. Conclusions. During postnatal growth, the DC population of the iris develops initially as an OX62-positive-MHC class II-negative population, which then develops increasing MHC class II expression in situ and finally resembles classic DC populations in other tissue sites. Maturation of the iris DC population is temporally delayed compared with time to maturation in other tissue sites in the rat.