Rohrer's constant, K2, as a factor of determining inspiratory resistance of common adult endotracheal tubes

The aim of the study was to calculate the in vitro inspiratory resistance (R(ETT)) of adult endotracheal tubes (ETT), via the end-inspiratory occlusion method, and to apply this method in vivo in order to estimate R(ETT) value in real time. By plotting R(ETT) over inspiratory flow (V) and calculating Rohrer's coefficients of linear and nonlinear resistance, K1 and K2 respectively, we determined the resistive behaviour of each ETT. Peak and plateau pressures were recorded at both proximal and distal sites of the ETT after applying a three-second occlusion under constant flow. Distal pressure was obtained via an intraluminal catheter R(ETT) was calculated as (P(peak) - P(plateau))/(V), at both sites. R(ETT) value resulted from the difference R(proximal) - R(distal). Graph R(ETT) over (V) was plotted and Rohrer's constants were calculated by the method of least squares. For ETTs with inner diameter 9.0, 8.5, 8.0, 7.5, 7.0 and 6.5 mm, K2 was 2.42, 3.05, 4.65, 6.01, 9.17 and 12.80 cmH2O/l/s, respectively. The intraluminal catheter increased R(ETT) No.7.0 by an average of 49%. Finally, ten patients with partially obstructed ETTs were tested and K2 in vivo constants found to be higher than their corresponding in vitro values (P value 0.00012). Therefore, knowing the performing size of an ETT may help the clinicians identify ETT obstruction and deal with weaning problems.

Gastrointestinal stromal tumor

BACKGROUND

GISTs are a subset of mesenchymal tumors and represent the most common mesenchymal neoplasms of GI tract. However, GIST is a recently recognized tumor entity and the literature on these stromal tumors has rapidly expanded.

METHODS

An extensive review of the literature was carried out in both online medical journals and through Athens University Medical library. An extensive literature search for papers published up to 2009 was performed, using as key words, GIST, Cajal's cells, treatment, Imatinib, KIT, review of each study were conducted, and data were abstracted.

RESULTS

GIST has recently been suggested that is originated from the multipotential mesenchymal stem cells. It is estimated that the incidence of GIST is approximately 10-20 per million people, per year.

CONCLUSION

The clinical presentation of GIST is variable but the most usual symptoms include the presence of a mass or bleeding. Surgical resection of the local disease is the mainstay therapy. However, therapeutic agents, such as Imatinib have now been approved for the treatment of advanced GISTs and others, such as everolimus, rapamycin, heat shock protein 90 and IGF are in trial stage demonstrate promising results for the management of GISTs.

Serum of patients with septic shock stimulates the expression of Trem-1 on U937 monocytes

OBJECTIVES

To describe the concentrations of sTREM-1 in patients with sepsis and to explore the effects of their serum on the expression of TREM-1 on U937 monocytes.

METHODS

Blood was sampled at regular time intervals in 56 patients with sepsis. Concentrations of tumour necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1alpha), IL-6, IL-8, IL-10 and IL-12p70 and sTREM-1 were measured. U937 monocytes were incubated in the presence of serum at sepsis onset.

RESULTS

Median sTREM-1 concentration on day 1 for patients with septic shock was 915 pg/ml and 228.5 pg/ml for those without shock (p = 0.002). TNFalpha, IL-1alpha, IL-6, IL-8 and IL-10 did not differ between them. A positive correlation was found between changes of sTREM-1 and SOFA scores from day 1 to 7. Sera of patients with septic shock evoked a significant increase of the expression of TREM-1. The concentrations of TNFalpha and IL-8 in supernatants increased only after stimulating with sera of patients without shock, but not after stimulating with sera of patients with shock.

CONCLUSIONS

Levels of sTREM-1 correlated with sepsis severity. sTREM-1 is considerably higher in patients with shock compared to patients without shock. The serum of shocked patients could stimulate the expression of TREM-1 on U937 monocytes.

Wavelet analysis of head acceleration response under dirac excitation for early oedema detection

The present work deals with the application of an innovative in-house developed wavelet-based methodology for the analysis of the acceleration responses of a human head complex model as a simulated diffused oedema progresses. The human head complex has been modeled as a structure consisting of three confocal prolate spheroids, whereas the three defined regions by the system of spheroids, from the outside to the inside, represent the scull, the region of cerebrospinal fluid, and the brain tissue. A Dirac-like pulse has been used to excite the human head complex model and the acceleration response of the system has been calculated and analyzed via the wavelet-based methodology. For the purpose of the present analysis, a wave propagation commercial finite element code, LS-DYNA 3D, has been used. The progressive diffused oedema was modeled via consecutive increases in brain volume accompanied by a decrease in brain density. It was shown that even a small increase in brain volume (at the level of 0.5%) can be identified by the effect it has on the vibration characteristics of the human head complex. More precisely, it was found that for some of the wavelet decomposition levels, the energy content changes monotonically as the brain volume increases, thus providing a useful index of monitoring an oncoming brain oedema before any brain damage appears due to uncontrolled intracranial hypertension. For the purpose of the present work and for the levels of brain volume increase considered in the present analysis, no pressure increase was assumed into the cranial vault and, associatively, no brain compliance variation.

The frequency and distribution of mast cells in pleomorphic adenomas of salivary glands

AIM

To investigate whether the frequency and distribution of mast cells (MCs) in pleomorphic adenomas (PAs) of major and minor salivary glands justifies the suggestion that there exists an association between MCs and mucoid stromal changes in PAs.

METHODS

The material consisted of 22 cases of pleomorphic adenoma (eight arising in major and 14 in minor salivary glands) and a control group represented by five cases of monomorphic adenoma (MA). Representative 3-microm thick, paraffin-embedded sections were stained with H&E and Azur A. Computer-aided image analysis was performed in order to evaluate the relative surface area occupied by epithelial and connective tissue components, as well as the absolute number of MCs.

RESULTS

According to our findings, PAs from minor salivary glands contain significantly greater numbers of mast cells compared with tumours from major glands. Additionally, the distribution of MCs within the stromal connective tissue appeared not to be random.

CONCLUSION

It is possible that differences in the pattern of connective tissue might influence the actual concentration of MCs and that these differences are responsible for the observed variations between major and minor gland PAs.

Purification and biological properties of an epithelial intestinal cell growth inhibitor from a human small intestine

Endogenous mitotic inhibitors act as control-mechanisms in intestinal epithelium proliferation. The presence of an inhibitor of cultured intestinal epithelial cell from a villous extract of rat jejunum has been reported in one of our papers. The object of the study now reported was to find the presence of a growth inhibitor in the villous extract from man's small intestine and to purify and characterize this factor when found. Our results reveal that: (1) Such an inhibitor was found in a supernatant preparation obtained from human intestinal epithelial cells. The inhibition of the proliferation of epithelial cells (IRD-98) it induced was seem to be dose-dependent and non-cytotoxic. (2) After chromatography on hydroxylapatite, on DEAE and then on ACA 54 (gel permeation), a low-molecular-weight protein (15 kDa) called purified intestinal inhibitor (PII) was isolated (purification factor of approx. 50,000 with respect to the supernatant fraction). This fraction proved to inhibit the IRD-98 cells in a reversible manner. When cells are incubated with this protein, cells prove to be arrested in phase G1 of the cell cycle as is revealed by the flow cytometry studies. The results obtained support the hypothesis that regulation of cell proliferation is mediated by endogenous inhibitors at the epithelial level.

Effects of an inhibitor isolated from human small intestine on organ culture of intestinal mucosa

Endogenous mitotic inhibitors have been implicated as controlling mechanisms of intestinal epithelium proliferation. We previously reported the purification of an inhibitor of intestinal epithelial cells in culture isolated from a villous extract of human jejunum. This article describes the biologic effects of this inhibitor on organ cultures of rabbit intestinal mucosa. Our results reveal that (1) this factor is not cytotoxic; (2) it inhibits intestinal epithelial cell proliferation in a dose-dependent and reversible manner; (3) it does not appear to be species-specific; (4) it is specific to the digestive tract, and more particularly to the small intestine.

Evaluation of aztreonam in difficult-to-treat infections with prolonged posttreatment follow-up

Aztreonam at doses of 1 or 2 g given intramuscularly or intravenously every 8 h for 7 to 42 days was given to 55 patients, most of them suffering from difficult-to-treat infections either because the isolated pathogens were multiresistant or because of the location of the infection. Infections included: urinary tract (23 cases), deep soft tissue phlegmon (12 cases), chronic osteomyelitis in exacerbation (7 cases), abscesses (7 cases), pneumonia (4 cases), and external otitis (2 cases). In culture specimens, Pseudomonas aeruginosa (24 isolates) and various Enterobacteriaceae species (37 isolates) were isolated with MICs ranging from 0.25 to 16 micrograms/ml. Clinically, at the completion of treatment and after a 6-week posttreatment follow-up, 45 (81.6%) patients were cured, 4 (7.2%) improved, 3 (5.6%) relapsed, and 3 (5.6%) failed to respond to therapy. Bacteriologically, at the end of treatment, the pathogen was eradicated in 50 patients (91%) and persisted in 5 (9%). After a 6-week follow-up, cultures remained sterile in 33 patients (60.0%), 16 (29.1%) relapsed, in 6 (10.9%) bacteria persisted, and superinfection was reported in 4 (7.3%) patients. No appreciable adverse effects or toxicity was observed. From the reported results, it is concluded that aztreonam is a valuable addition to the field of antimicrobial chemotherapy that can be used effectively and safely in the treatment of a variety of gram-negative infections.