Force balancing in mammographic compression.

PURPOSE: In mammography, the height of the image receptor is adjusted to the patient before compressing the breast. An inadequate height setting can result in an imbalance between the forces applied by the image receptor and the paddle, causing the clamped breast to be pushed up or down relative to the body during compression. This leads to unnecessary stretching of the skin and other tissues around the breast, which can make the imaging procedure more painful for the patient. The goal of this study was to implement a method to measure and minimize the force imbalance, and to assess its feasibility as an objective and reproducible method of setting the image receptor height. METHODS: A trial was conducted consisting of 13 craniocaudal mammographic compressions on a silicone breast phantom, each with the image receptor positioned at a different height. The image receptor height was varied over a range of 12 cm. In each compression, the force exerted by the compression paddle was increased up to 140 N in steps of 10 N. In addition to the paddle force, the authors measured the force exerted by the image receptor and the reaction force exerted on the patient body by the ground. The trial was repeated 8 times, with the phantom remounted at a slightly different orientation and position between the trials. RESULTS: For a given paddle force, the obtained results showed that there is always exactly one image receptor height that leads to a balance of the forces on the breast. For the breast phantom, deviating from this specific height increased the force imbalance by 9.4 ± 1.9 N/cm (6.7%) for 140 N paddle force, and by 7.1 ± 1.6 N/cm (17.8%) for 40 N paddle force. The results also show that in situations where the force exerted by the image receptor is not measured, the craniocaudal force imbalance can still be determined by positioning the patient on a weighing scale and observing the changes in displayed weight during the procedure. CONCLUSIONS: In mammographic breast compression, even small changes in the image receptor height can lead to a severe imbalance of the applied forces. This may make the procedure more painful than necessary and, in case the image receptor is set too low, may lead to image quality issues and increased radiation dose due to undercompression. In practice, these effects can be reduced by monitoring the force imbalance and actively adjusting the position of the image receptor throughout the compression.

von Willebrand factor activation, granzyme-B and thrombocytopenia in meningococcal disease.

SUMMARY BACKGROUND: During invasive meningococcal disease, severe thrombocytopenia is strongly associated with a poor outcome. OBJECTIVES: In order to elucidate the pathophysiological mechanism behind the development of thrombocytopenia, we studied the role of von Willebrand factor (VWF) in meningococcal disease. PATIENTS/METHODS: Thirty-two children with severe meningococcal disease admitted to our university hospital were included in this study. VWF and related parameters were measured and results were correlated with the development of shock and thrombocytopenia. RESULTS: At admission, all patients had increased levels of (active) VWF and VWF propeptide. The highest VWF propeptide levels were observed in patients with shock, indicating acute endothelial activation. Although VWF propeptide levels in patients with shock, with or without thrombocytopenia, were similar, increased active VWF was significantly lower in patients with thrombocytopenia as compared with patients without thrombocytopenia. ADAMTS13 was moderately decreased. However, the VWF multimeric pattern was minimally increased. We assume that these findings are explained by VWF consumption and perhaps by granzyme B (GrB). In vitro experiments showed that GrB is able to cleave VWF multimers in plasma, whereas GrB was high in patients with shock, who developed thrombocytopenia. CONCLUSIONS: Our results demonstrate that consumption of VWF, derived from endothelial cells, could be a key feature of meningococcal disease and primary to the development of thrombocytopenia during shock.

Anomalous coronary artery from the wrong sinus in a 15-year-old boy.

Congenital coronary artery anomalies are a well-recognized risk factor for sudden cardiac death in children as well as young adults, mostly during or immediately after intense exertion on the athletic field. Because these malformations are amenable to surgical treatment, timely identification is crucial. Unfortunately, antemortem diagnosis is notoriously difficult, partly due to the absence of abnormal test results in routine investigations. We present a 15-year-old boy who collapsed during exercise due to ventricular fibrillation. Coronary abnormalities were initially not identified, but they were clearly visualized by means of an echocardiogram and confirmed by multislice computed tomography. We would like to emphasize that echocardiography is capable of accurately identifying congenital coronary anomalies when attention is paid to the correct diagnostic hallmarks.

The absent and vanishing spleen: congenital asplenia and hyposplenism--two case reports.

UNLABELLED: Two unrelated patients are reported: one with isolated familial asplenia diagnosed postmortem, the other with isolated hyposplenism diagnosed after recurring invasive bacterial infections. Because both children died of fulminant septic shock, the importance of early diagnosis of splenic dysfunction is evident. Clues for an early diagnosis of congenital asplenia are recurrent invasive bacterial infections, Howell-Jolly bodies in the blood smear or a relative with congenital isolated asplenia. Although the guidelines for infection prevention in asplenism--patient education, antibiotic prophylaxis and vaccination--are well defined, controversy remains as to how to differentiate hyposplenism from functional asplenism. CONCLUSION: Based on the present observations, we define a patient as functionally asplenic--and therefore at risk for life-threatening infections-when Howell-Jolly bodies are present in the blood smear, a very small spleen is found by ultrasound, or splenic blood flow is compromised.

In-vitro susceptibility and molecular characterisation of macrolide resistance mechanisms among Streptococcus pneumonia isolates in The Netherlands: the DUEL 2 study.

In total, 881 presumptive clinical isolates of Streptococcus pneumoniae collected from throughout The Netherlands were analysed to determine their mechanisms of macrolide resistance. Isolates were identified initially by participating laboratories using their own standard identification technique, followed by determination of MICs with Etests. Only 797 isolates were confirmed as pneumococci following bile-solubility tests, lytA PCR and 16S rRNA sequencing. Of these confirmed pneumococci, 59 (7.4%) isolates were macrolide-resistant. Analysis by PCR indicated that 34 (57.6%) isolates harboured only the erm(B) gene and 16 (27.1%) only the mef gene. Three (5.1%) isolates carried both erm(B) and mef, while six (10.2%) isolates were negative for both mechanisms. Of the six negative isolates, three had a mutation in the 23S rRNA gene, and three were negative for all mechanisms tested. No isolates with the erm(A) subclass erm(TR) gene were detected. Among the 19 mef-positive isolates, 14 (73.7%) carried the mef(A) gene, and only five (26.3%) carried the mef(E) gene. No linezolid cross-resistance or multiresistance (resistance to more than two classes of antibiotics) was observed.

Resistance to both complement activation and phagocytosis in type 3 pneumococci is mediated by the binding of complement regulatory protein factor H.

To study the role of surface-associated proteins in the virulence of Streptococcus pneumoniae, we used two serotype 3 strains, ATCC 6303 and WU2, and two PspA-negative mutants of WU2, an encapsulated one, JY1123 (Caps(+)/PspA(-)), and an unencapsulated one, DW3.8 (Caps(-)/PspA(-)). ATCC 6303 and WU2 were highly virulent in mice, while the virulence of JY1123 was slightly decreased (50% lethal doses [LD(50)s], 24, 6, and 147 CFU/mouse, respectively); DW3.8 was avirulent (LD(50), 2 x 10(8) CFU). In vitro, ATCC 6303, WU2, and JY1123 (Caps(+)/PspA(-)) strongly resisted complement activation and complement-dependent opsonophagocytosis, whereas DW3.8 (Caps(-)/PspA(-)) was easily phagocytized in fresh serum. Trypsin treatment of ATCC 6303, WU2, and JY1123 (Caps(+)/PspA(-)) resulted in enhanced complement activation and complement-dependent opsonophagocytosis. Trypsin had no deleterious effect on the polysaccharide capsule. In addition, trypsin pretreatment of ATCC 6303 strongly reduced virulence upon intraperitoneal challenge in mice. This indicated that surface proteins play a role in the resistance to complement activation and opsonophagocytosis and contribute to the virulence of type 3 pneumococci. In subsequent experiments, we could show that the modulation of complement activation was associated with surface components that bind complement regulator factor H; binding is trypsin sensitive and independent of prior complement activation. Immunoblotting of cell wall proteins of the virulent strain ATCC 6303 with anti-human factor H antibody revealed three factor H-binding proteins of 88, 150, and 196 kDa. Immunogold electron microscopy showed a close association of factor H-binding components with the outer surface of the cell wall. The role of these factor H-binding surface proteins in the virulence of pneumococci is interesting and warrants further investigation.

Plasma patterns of tumor necrosis factor-alpha (TNF) and TNF soluble receptors during acute meningococcal infections and the effect of plasma exchange.

In 39 patients with acute meningococcal infections, the plasma concentrations of tumor necrosis factor-alpha (TNF) and its soluble receptors (sRs) TNFsR-p55 and TNFsR-p75 were measured from admission till recovery. At admission, patients with shock had significantly higher TNF, TNFsR-p55, and TNFsR-p75 values than patients without shock. In addition, during the first 24 hours, patients with shock had higher TNFsR-p75 to TNFsR-p55 ratios, indicating that in shock the increase of TNFsR-p75 exceeds that of TNFsR-p55. TNF measured more than 12 hours after admission failed to differentiate between shock and nonshock because TNF concentrations normalized within 12-24 hours. However, because concentrations of TNFsRs remained elevated for 5-6 days, at that time plasma TNFsRs still differentiated between shock and nonshock. Plasma exchange or whole blood exchange (PEBE), performed in 20 patients with shock, accelerated the decrease of plasma TNFsRs. However, because of a rebound after each PEBE session, the overall half-lives of both TNFsRs were not affected by PEBE.

Posttranscriptional down-regulation of tumor necrosis factor-alpha and interleukin-1beta production in acute meningococcal infections.

The regulation of tumor necrosis factor-alpha (TNF) and interleukin-1beta (IL-1beta) production was studied in patients with meningococcal disease. Circulating TNF and IL-1beta normalized within 1 day. TNF mRNA and IL-1beta mRNA in white blood cells decreased over 3-4 days. During the acute stage, TNF and IL-1beta production in stimulated whole blood cultures was down-regulated. After 4-5 days, this production was restored. The down-regulation was unlikely to be caused by circulating IL-6 and IL-10, as these cytokines normalized within 2-3 days. TNF mRNA in stimulated cultures during the acute stage, with down-regulated production, did not differ from that at recovery, with restored production. In contrast, the down-regulated production of IL-1beta was associated with significantly lower IL-1beta mRNA levels. Thus, TNF and IL-1beta production are differentially regulated. Whereas TNF production is regulated posttranscriptionally, IL-1beta production is also regulated at the mRNA level.

A normal platelet count at admission in acute meningococcal disease does not exclude a fulminant course.

OBJECTIVE: To determine the value of the platelet count at admission for the assessment of the severity of disease in acute meningococcal infections. DESIGN: Retrospective and prospective, descriptive patient study. SETTING: University Hospital Intensive Care Unit (ICU). PATIENTS: All patients (n = 92) with acute meningococcal disease from 1985 to 1997, who arrived at the ICU within 12 h after hospital admission and had more than one platelet count during the first 12 h. MEASUREMENTS AND RESULTS: After admission, platelets dropped in 95% of the patients. At admission, 2/41 (5%) of the non-hypotensive patients and 13/51 (25%) of the hypotensive patients had platelets fewer than 100 x 10(9)/l. During the following 12 h, these percentages increased to 15% and 71%, respectively. Fatalities had, at admission, a median platelet count of 111 x 10(9)/l (range, 19-302 x 10(9)/l), whereas the nadir, occurring at median 7.0 h (range, 1.3-12 h), was 31 x 10(9)/l (range, 12-67 x 10(9)/l). Plasma TNF, measured shortly after admission, correlated better with the platelet nadir (r = -0.65, p < 0.0001) than with the platelet count at admission. Similarly, serum lactate correlated better with the platelet nadir. CONCLUSIONS: As platelets drop after admission, the use of the platelet count at admission for the assessment of the prognosis in acute meningococcal disease may be misleading. Frequently repeated platelet counts are a better tool for evaluating the severity of disease.

[Problems of resistance in Streptococcus pneumoniae]. / Resistentieproblemen bij Streptococcus pneumoniae.

Penicillin-resistant pneumococci are an increasing worldwide problem that until now has spared the Netherlands and a small number of other European countries. In countries with resistant pneumococci empirical therapy of otitis media and of meningitis is difficult. Special antibiotics such as clindamycin and ceftriaxone may be needed or combinations of vancomycin and high doses of cephalosporin. In spite of antibiotic resistance pneumococcal pneumonia can be treated successfully with high doses of benzylpenicillin or cephalosporin. In case of an infection outside the central nervous system, it is not clear what level of minimal inhibitory concentration indicates that therapy will fail, probably > 4 mg/l. Even in regions with much resistance such levels are rare. It is fortunate that antibiotic resistance only occurs in a limited number of pneumococcal strains, which in addition happen to be included in antipneumococcal vaccines.

Disseminating infection with Scytalidium dimidiatum in a granulocytopenic child.

A 13-year-old Moroccan boy in The Netherlands developed fever and a lesion resembling ecthyma gangrenosum on the abdomen during cytostatic drug treatment for a lymphoblastic B-cell lymphoma. Scytalidium dimidiatum was cultured from blood and the abdominal skin lesion. The patient was successfully treated with amphotericin B. The fungus Scytalidium dimidiatum is a fairly common plant pathogen in tropical and subtropical countries and is known to cause dermatomycoses in humans in these areas. This case demonstrates that it is necessary to be aware that immigrants from these areas can import their own fungal flora, some members of which may cause life-threatening disease in the case of patients with immune suppression.

[Care for brothers and sisters of crib death children. Evaluation of a support project as an alternative to home monitoring]. / Zorg voor broertjes en zusjes van wiegedood-kinderen. Evaluatie van een begeleidingsproject over een alternatief voor de home-monitor.

A pilot-study was carried out on support measures chosen by 40 families having a subsequent child after their experience with a cot-death infant. Cardio-respiratory monitors were used in one group and weighing scales in the other. General support measures given to both groups included the keeping of symptom charts and weekly visits by health-nurses. Parents who used a home-monitor relied upon the medical-technical approach of the problem, while parents using scales were mainly given confidence by the personal attention of the health-nurse. Monitor-parents more often called the paediatrician for advice than parents using weighing-scales. Especially parents who used weighing-scales commented on the great value of the symptom diary and the weekly home-visit of the health-nurse.

[Cephalosporins: microbiological and pharmacokinetic properties, application to pediatrics]. / Cefalosporines: microbiologische en farmacokinetische eigenschappen, toepassingsgebieden in de pediatrie.

Many cephalosporins are presently available for clinical use. Although the cephalosporins are excellent antimicrobial agents for many infectious diseases in childhood, they have not replaced the older antibiotic regiments. In fact they offer the pediatrician a broader range of choices in treatment. This article gives a review on microbiological and pharmacokinetic properties of cephalosporins and an indication for the use of cephalosporins in pediatric therapy.

[The importance of pressure registration in mask-balloon ventilation]. / Het belang van drukregistratie bij masker-ballon beademing.

In positive pressure hand ventilation appropriate ventilatory pressures are essential for effectiveness and safety of treatment. Workers in a Neonatal Intensive Care Unit were asked to ventilate an imaginary patient. A diaphragm-manometer was used for measurements. This manometer was only visible to the investigator. Peak inspiratory pressure (PIP) and peak end expiratory pressure (PEEP) were recorded. Rather great differences in administered PIP were observed. Unintentionally, PEEP was given in many cases. It is concluded, that in positive pressure hand ventilation pressures should be monitored by measurement.