Bordetella holmesii bacteraemia in an individual on haemodialysis.

A case of haemodialysis-associated bacteraemia due to Bordetella holmesii is described. Commercially available identification kits failed to identify the isolate, which was speciated using 16s rRNA gene sequencing. B. holmesii is a rare cause of bacteraemia, endocarditis and pneumonia in the immunosuppressed and may also cause a pertussis-like illness.

Pulmonary infection with Scedosporium prolificans in an immunocompetent individual.

We report a case of histologically confirmed Scedosporium prolificans pulmonary infection secondary to long-standing bronchiectasis that necessitated excision lung surgery. This case emphasizes the difficulties with the medical management of deep-seated fungal infections.

Community-acquired methicillin-resistant Staphylococcus aureus brain abscess in an immunocompetent individual.

A 52-y-old woman with a community-acquired methicillin-resistant Staphylococcus aureus brain abscess who was successfully treated with surgical drainage and antibiotics is described. The increase in community-acquired methicillin-resistant S. aureus and the impact this will have on empirical treatment of such infections are discussed.

Radiation dose to otologic structures during head and neck cancer radiation therapy.

BACKGROUND: Otologic structures are often contained within head and neck cancer radiation treatment ports. The dosimetry to otologic structures has not been routinely analyzed and radiation treatment planning does not currently attempt to specifically avoid the inner ear structures when dosimetry is calculated. Recent studies demonstrate that up to 30% of patients experience sensorineural hearing loss on multimodality therapy with cisplatin and radiation. METHODS: In the current case series, radiation dosimetry to otologic structures was calculated from computed tomogram treatment plans on patients. Fifteen nasopharyngeal, oral cavity, oropharyngeal, and hypopharyngeal cancer patients were analyzed. RESULTS: Between 8% and 102% of the total dose is delivered to the petrous bone/cochlea, with 4 of 15 patients getting more than 50% of the dose to at least one cochlea The mastoid air cells received between 3% and 75% of the total dose, with higher doses being delivered to patients with bulky high neck metastases or nasopharyngeal tumors. The eustachian tubes received between 20% and 102% of the total dose, with 10 of 15 patients receiving more than 50% of the dose to this anatomic site. CONCLUSION: We conclude that the cochlea and eustachian tubes receive significant radiation during treatment, particularly in nasopharyngeal cancer patients. Careful design of radiation treatment ports may allow for the reduction of radiation to hearing structures.

Head and neck compensation for total body irradiation using opposed laterals.

Using shaped brass compensators that follow the coronal profile of a patient's head and neck, we confirm that adequate compensation can be made to prevent overdosing in these regions when delivering total body irradiation using opposed lateral fields. Initially, these compensators were custom made for each patient, but we have shown that the variation from patient to patient is sufficiently small that individual compensators can be used for a number of different patients without compromising the dose distribution. In a subgroup of 35 patients on whom diode measurements were made, 20 used compensators from the library of approximately 40 compensators made for previous patients and 15 required new compensators to be fabricated. No significant difference (3.4% on average) was observed in the dose distribution. By examining the profiles accumulated from 81 patients, we have shown that the primary difference between patients is not in the shape of the head and neck, but in the distance from the top of the head to the suprasternal notch and in the slope of the shoulders; thus, shaped compensators are not necessary and the same quality of dose homogeneity can be achieved using simple flat brass plates. Further, if the arms are supported so that the slope of the shoulders is constant, a relatively small number (15) of square-ended plates of thickness ranging from 4.0 to 11.0 mm would be sufficient to treat all 81 patients in our sample.

Leech-borne Serratia marcescens infection following complex hand injury.

Leeches are commonly used in the postoperative course of plastic surgical operations where there is venous congestion in a pedicled or free flap. They provide a temporary relief to venous engorgement whilst venous drainage is re-established. It is known that leeches can carry Aeromonas hydrophila infection, and a second or third generation cephalosporin antibiotic has traditionally been given as prophylaxis against infection. We report a new observation that leeches can carry Serratia marcescens and give rise to clinically significant infection. The implication for prophylaxis and treatment of leech-associated cellulitis is discussed.

Radioprotection of hematopoietic tissue by fibroblast growth factors in fractionated radiation experiments.

Acidic and basic fibroblast growth factors (FGF(1/2)) myeloprotect mice in single dose total body irradiation (TBI) experiments with a dose modification factor (DMF) of approximately 1.15. CFU-C assay suggests that one of the mechanisms is augmentation of the shoulder of the radiation dose response curve, and thus protection could be greater with fractionation. Four equal fractions of TBI were delivered to C3H/He mice at times 0 h, 8 h, 24 h, and 32 h. FGF(1/2) dose was 3 microg per i.v. injection given 24 and 4 hrs before the first radiation dose. FGF2 treated mice had a significant survival advantage over saline-treated mice with a DMF of 1.22 +/- 0.07 (p < 0.01). Adding a third dose of FGF2, had no additional benefit on LD(50/30) (dose of radiation lethal to 50% of animals measured at day 30) (DMF = 1.23 +/- 0.06, p < 0.01). FGF1 was not as effective with fractionation (DMF = 1.04 +/- 0.03). Increased survival in FGF2 treated mice was due to the a more rapid recovery of bone marrow hematopoietic cells and peripheral WBC, RBC and platelets. FGF2 may prove a useful treatment response modifier in clinical fractionated irradiation.

An approach to dose measurement for total body irradiation.

PURPOSE: An approach is proposed to allow the interpretation of diode measurements on patients receiving total body irradiation (TBI) in opposed lateral fields as midplane dose measurements. METHODS AND MATERIALS: This technique consists of making measurements on both entrance and exit sides of any ray path along which the midplane dose is desired. The diode on the entrance side is calibrated so that its output is indicative of the dose delivered at the depth of maximum dose along the ray. The diode on the exit side is calibrated so that its output represents the dose that would have been delivered to that depth had the medium (the patient) been semi-infinite. Because these two measurements lie along the same ray, they are related by a simple depth-dose equation from which the effective absorption coefficient (mueff) can be determined. The dose at the midplane is calculated using this mueff in a similar equation. RESULTS: The validity of this approach was checked with measurements at isocenter and at the TBI distance using a polystyrene phantom. In both cases, the calculated midplane dose was within reasonable experimental error (range approximately +/- 2% on average) of the measured dose. Measurements on eight patients showed the excellent reproducibility of entrance surface measurements (standard deviation [SD] approximately +/- 1%), compared to that of midplane measurements (SD approximately +/- 4%) and exit surface measurements (SD approximately < or = 8%). Midplane doses determined from these equations confirmed that dose inhomogeneity using this opposed lateral technique is on the order of +/- 10% with highest doses delivered to the calves and lowest to the lungs. CONCLUSION: Recent measurements made on TBI patients have shown that a commercial eight-diode system can be used successfully to measure the dose delivered to the midplane within an accuracy of approximately +/- 4%. The reproducibility of entrance surface measurements (approximately +/- 1%) shows that such measurements provide the accuracy required for quality assurance purposes.

Rapid scanning with the fabry-perot etalon.

A brief description of the principles of the scanning Fabry-Perot spectrometer is followed by an introductory survey of the various F-P spectrometers that have been used successfully. The limits of rapid scanning F-P spectroscopy are considered with regard to time resolution, wavelength resolution, and the size of the wavelength interval scanned. These considerations indicate that it is already feasible to scan a wavelength interval up to approximately 30 A in times down to 0.3 microsec with an over-all finesse of 20, but under these conditions the useful aperture is restricted to only 1-cm diam. Present spectrometers are limited in their time resolution by the breaking strengths of ceramic components. Finally, various applications of the rapid scanning F-P spectrometer are discussed.