Evaluation of fluorodeoxyglucose positron emission tomography in the management of soft-tissue sarcomas

We performed a retrospective analysis to evaluate the ability of whole-body F-fluorodeoxyglucose positron emission tomography (FDG PET) to identify local recurrence and pulmonary metastases in patients with soft-tissue tumours after treatment. We compared the results of FDG PET with those of MRI for the detection of local recurrence, and with CT of the chest for pulmonary metastases. We assessed 62 patients of mean age 51 years, who had 15 types of soft-tissue sarcoma, after a mean follow-up of 3 years 2 months. For the detection of local disease, 71 comparisons showed that the sensitivity and specificity of FDG PET were 73.7% and 94.3%, respectively; there were 14 true-positive and five false-negative results. MRI had a sensitivity and specificity of 88.2% and 96.0% respectively. For the identification of lung metastases, 70 comparisons showed that the sensitivity and specificity of FDG PET were 86.7% and 100%, with 13 true-positive results and two false-negative results. CT of the chest had a sensitivity and specificity of 100% and 96.4%. Thirteen other sites of metastases were identified by FDG PET. FDG PET can identify both local and distant recurrence of tumour as a one-step procedure and will detect other metastases. It seems that all three methods of imaging are needed to define accurately the extent of disease, both at initial staging and during follow-up.

Simultaneous comparison of the personal UV exposure of two human groups at different altitudes

A simultaneous comparison of human exposure to solar ultraviolet radiation at two locations was performed to study the effect of environmental factors and human attitudes on personal ultraviolet exposure. The study took place on 29 October 1996 in Toowoomba (27.5 degrees S, 151.9 degrees E) and Brisbane (27.4 degrees S, 153.1 degrees E), Queensland, Australia. From the data collected by calibrated ambient ultraviolet monitoring stations located in Toowoomba and Brisbane, Toowoomba received 68% more UVA (320-400 nm) and 61% more UVB (280-320 nm) than Brisbane from 07:00 to 10:00 Australian Eastern Standard Time (EST). From 10:00 to 17:00 EST Toowoomba received 5% more UVA and 20% less UVB than Brisbane. High ambient ultraviolet levels recorded by ultraviolet stations were reinforced by measurement of the personal ultraviolet exposure of human subjects wearing polysulfone dosimeters. Contrary to the common belief that the ultraviolet exposure to the human body is higher near the beach (i.e., coastal areas) than the inland area, the average erythemal weighted ultraviolet exposure on the chest and shoulder of each subject in the inland city of Toowoomba (127 km to the west of Brisbane) was 30% higher than in the coastal city of Brisbane from 07:00 to 17:00 EST. Evidence is also presented to suggest a relationship between altitude, climatic conditions, the human attitude, and the level of personal exposure to ultraviolet radiation.

Quantification of personal solar UV exposure of outdoor workers, indoor workers and adolescents at two locations in Southeast Queensland

Quantification of human exposure to solar ultraviolet (UV) radiation at two locations was performed to study the effect of occupation (outdoor workers, schoolchildren and home workers) and location on personal UV exposure. The study took place on 13 and 14 February 1997 in Toowoomba (27.5 degrees S, 151.9 degrees E) and Brisbane (27.4 degrees S, 153.1 degrees E) in Southeast Queensland, Australia. From the data collected by calibrated ambient UV monitoring stations located in Toowoomba and Brisbane, Toowoomba received 16% more UVB (280-320 nm) than Brisbane from 07:00 to 17:00 Australian Eastern Standard Time (EST) on the 13 February, 1997 and 10% more UVB on the 14 February 1997. All groups, regardless of occupation, in this study received a median erythemal UV exposure of over 2 MED on the shoulder over the 2 day period. The highest median erythemal UV exposure to the shoulder over the 2 day period was 6 MED in Toowoomba outdoor workers. The median 2 day erythemal exposure to the shoulder was 33% higher in Toowoomba than in Brisbane for the outdoor workers, 50% higher in Toowoomba compared to Brisbane for the schoolchildren and 25% higher in Toowoomba than Brisbane for the home workers.

The facial distribution of erythemal ultraviolet exposure in south-east Queensland

This paper presents a method for the evaluation of the distribution of the facial erythemal UV exposure and the erythemal UV exposure per unit area of the face using only eight dosimeters located on the vertex of the head, forehead, nose, chin, left and right ears and left and right cheeks. An overall picture of the parts of the face receiving high UV exposures is provided. The distribution of the erythemal UV exposure to the human face at a subtropical latitude was shown to change with time of year and with cloud cover. On two days with similar solar zenith angles, the ratio of the erythemal UV exposure to the nose compared with that on a horizontal plane changed from 0.47 to 0.84 with increased cloud cover. At the same time, the total erythemal exposure per unit area of the face dropped from 122 to 56 ml cm-2. Although the absolute exposures decreased, the nose received a relatively high exposure.

Quantitative evaluation of the personal erythemal ultraviolet exposure in a car

Erythemal ultraviolet (UV)-radiation exposure to the right hand, mid-arm, shoulder, chin, nose and left and right sides of the face has been evaluated in a car from a large family class and a car from a small car class. In the small car, the site with highest exposure received 2.2 times more radiation than the site with the highest exposure in the larger car. In both cars, highest erythemal exposures were to the right shoulder, arm, and hand. Over a 6 h period, erythemal exposure to the right shoulder of a person in the driver's seat of the small car was 3.1 mJ x cm(-2).

The erythemal ultraviolet exposure for humans in greenhouses

A spectrum evaluator has been employed to evaluate the erythemal exposure in late spring and late summer at three sites and five orientations at each site inside a glass greenhouse with black shadecloth over the glass roof. The maximum in the erythemal irradiance in the greenhouse is not necessarily at noon. Over a day, the maximum erythemal exposure occurred on the eastern side of the greenhouse in the morning and on the western side in the afternoon. The erythemal irradiance on the eastern side in the morning was higher by 26% and 50% for horizontal and vertical surfaces respectively compared with the same site at noon. On the western side the irradiance was higher by 45% and 78% for the horizontal and vertical surfaces respectively compared with the same site at noon. The erythemal irradiance inside the greenhouse does not vary as much during the day as it does outside; for example, for horizontal surfaces, the ratio of the erythemal irradiance outside to the average inside the greenhouse varies from 66 to 112 to 74 for the morning, noon and afternoon periods respectively. Over a 6 h period, the erythemal exposure to the shoulder for a standing posture in the greenhouse was 5 mJ cm-2.

Erythemal irradiances of filtered ultraviolet radiation

A spectrum evaluator (3 cm x 3 cm) employing four passive dosimeters has been used to evaluate the time averaged spectrum to allow calculation of the erythemal exposures resulting from the predominantly UVA component of filtered solar ultraviolet radiation. An exposure interval of approximately 20 min to autumn and spring sunshine was required for the spectrum evaluator to allow evaluation of the filtered source spectrum. For a clear spring day an erythemal exposure of 0.85 MED (minimum erythemal dose) to a horizontal plane and 0.38 MED to a vertical plane over a 6 h period was measured within a glass enclosure. For a partially cloudy day six weeks later, these were 0.89 and 0.44 MED for the horizontal and the vertical planes respectively. The ratios of the filtered to the unfiltered erythemal exposures within and outside the enclosure respectively ranged from 0.08 to 0.18 throughout the two days.

Detection of Aequorea victoria green fluorescent protein by capillary electrophoresis laser induced fluorescence detection

Aequorea victoria green fluorescent protein was assayed by capillary electrophoresis using post-capillary laser-induced fluorescence detection in a sheath flow cuvette. The limit of detection was 3.0 x 10(-12) M protein in an injection volume of 17 nL, corresponding to a mass of 3100 molecules.

Evaluation of the limits of visual detection of image misregistration in a brain fluorine-18 fluorodeoxyglucose PET-MRI study

In routine clinical work, registration accuracy is assessed by visual inspection. However, the accuracy of visual assessment of registration has not been evaluated. This study establishes the limits of visual detection of misregistration in a registered brain fluorine-18 fluorodeoxyglucose positron emission tomography to magnetic resonance image volume. The "best" registered image volume was obtained by automatic registration using mutual information optimization. Translational movements by 1 mm, 2 mm, 3 mm and 4 mm, and rotational movements by 1 degrees , 2 degrees , 3 degrees and 4 degrees in the positive and negative directions in the x- (lateral), y- (anterior-posterior) and z- (axial) axes were introduced to this standard. These 48 images plus six "best" registered images were presented in random sequence to five observers for visual categorization of registration accuracy. No observer detected a definite misregistration in the "best" registered image. Evaluation for inter-observer variation using observer pairings showed a high percentage of agreement in assigned categories for both translational and rotational misregistrations. Assessment of the limits of detection of misregistration showed that a 2-mm translational misregistration was detectable by all observers in the x- and y-axes and 3-mm translational misregistration in the z-axis. With rotational misregistrations, rotation around the z-axis was detectable by all at 2 degrees rotation whereas rotation around the y-axis was detected at 3-4 degrees . Rotation around the x-axis was not symmetric with a positive rotation being identified at 2 degrees whereas negative rotation was detected by all only at 4 degrees. Therefore, visual analysis appears to be a sensitive and practical means to assess image misregistration accuracy. The awareness of the limits of visual detection of misregistration will lead to increase care when evaluating registration quality in both research and clinical settings.

An estimate of the total UV-B exposure for outdoor workers during a south-east Queensland summer

A numerical model was used to calculate the facial UV-B exposure received during summer (December-February) by typical outdoor farm workers in south-east Queensland (27.5 degrees S), a population among the groups at highest risk of skin cancer. The exposure was calculated using new, more detailed measurements of the probability of outdoor activity of farmers (FO-measured by the Fraction of time spent Outside), the distribution of incident solar radiation on the human face (ER-the Exposure Ratio, measured by the fraction of the ambient radiation which falls on each site) and the ambient UV-B levels (AE-the Ambient Exposure) for the region. Only the exposure of unprotected faces was considered. An analysis of the distribution of exposure over a typical working day and of the likely spread of exposures is also presented. The group average of exposures at three facial sites (the forehead, nose and cheek) were 8.7 J cm(-2), 14.0 J cm(-2), and 9.5 J cm(-2), respectively, which is substantially higher than estimates for summer made for populations in more temperate latitudes.

A study on the involvement of GABAB receptor ligands in stress-induced antinociception in male mice

Swimming at 21 degrees C for 3 min induced antinociceptive effects in male mice with all animals showing a significant increase in response time to the hot plate test measured 10 min after swimming. This antinociceptive activity was still evident at 20 min after swimming. Prior administration of the GABAB receptor agonist, baclofen, potentiated the swimming-induced antinociception. For the group receiving the higher dose of baclofen (2.0 mg/kg, s.c.) the potentiation was still evident 40 min postswimming. However, prior administration of CGP-35348, a GABAB receptor antagonist, had no effect on the antinociceptive activity observed after swimming. Restraint for 1 h also induced significant antinociceptive activity in male mice. This restraint-induced antinociceptive activity was enhanced by prior administration of baclofen and was completely abolished by the administration of CGP-35348 before restraint. The present findings suggest that GABAB receptors may play a role in stress-induced antinociception and different GABAB receptor subtypes may be involved depending on the nature of the stress.

Assessment of the exposure to biologically effective UV radiation using a dosimetric technique to evaluate the solar spectrum

A cost-effective method employing polysulphone, nalidixic acid, 8-methoxypsoralen and phenothiazine as UV dosimeters is presented for evaluating the UV spectrum. The exposure measured by each dosimeter is a function of the source spectrum and the spectral response of the material. Each material has a different spectral response and records a different dose for the same exposure. A least squares method is employed to extract the source spectrum from the four dose measurements. A number of spectra have been evaluated, and the differences between these spectra and the associated irradiances, compared to the spectra and irradiances measured with a calibrated spectroradiometer is less than 20%. The technique allows simultaneous multisite measurement at positions that may be inaccessible to sensitive and expensive equipment. The technique was employed to evaluate the spectrum on the chest and shoulder of four subjects. The erythemal exposures were derived from the evaluated spectra with the chest exposures 0.7 to 0.8 those of the shoulder exposures.

Traumatic stress--an overview of diagnostic evolution and clinical treatment

This paper provides an overview of recent advances in the study of traumatic stress, with a special focus on the categorical and conceptual evolution in aetiological, diagnostic classification of post traumatic stress disorder (PTSD). A review update on psychological and pharmacological therapies relevant to the management of PTSD, and the trend towards a multi-layered, biopsychosocial approach is discussed. This review also includes an update of the risk factors and mediating factors associated with post traumatic responses.

Erythemally effective and actinic irradiance from a tungsten halogen lamp

A protocol for assessment of biological hazard from ultraviolet radiation sources was developed. The protocol utilized both a ultraviolet radiation spectroradiometer and a broadband ultraviolet radiation meter for the determination of the erythemally effective irradiance and the actinic irradiance. A 250 W tungsten halogen lamp operating at 9.5 A was tested with this protocol. It was found that the erythemally effective irradiance varied from 41 microW cm(-2) at 10 cm to 1.5 microW cm(-2) at 50 cm. In the same range of distances, the actinic irradiance decreased from 23 to 0.5 microW cm(-2). The irradiance from the source was uniform within 30 degrees about the line perpendicular to the axis of the filament. Using the recommendation of the Australian radiation protection agency, the National Health and Medical Research Council, the maximum allowable exposure time at the distance of 50 cm in the direction perpendicular to the axis of the filament was about 33.3 minutes.

A low, adaptive dose of gamma-rays reduced the number and altered the spectrum of S1- mutants in human-hamster hybrid AL cells

We examined the effects of a low, adaptive dose of 137Cs-gamma-irradiation (0.04 Gy) on the number and kinds of mutants induced in AL human-hamster hybrid cells by a later challenge dose of 4 Gy. The yield of S1- mutants was significantly less (by 53%) after exposure to both the adaptive and challenge doses compared to the challenge dose alone. The yield of hprt- mutants was similarly decreased. Incubation with cycloheximide (CX) or 3-aminobenzamide largely negated the decrease in mutant yield. The adaptive dose did not perturb the cell cycle, was not cytotoxic, and did not of itself increase the mutant yield above background. The adaptive dose did, however, alter the spectrum of S1- mutants from populations exposed only to the adaptive dose, as well as affecting the spectrum of S1- mutants generated by the challenge dose. The major change in both cases was a significant increase in the proportion of complex mutations compared to small mutations and simple deletions.

Speech-related visualization of laryngeal muscles with fluorine-18-FDG

This study describes the physiological uptake of 18F-fluoro-2-deoxyglucose (FDG) by the laryngeal muscles secondary to activation of the patient's vocal folds and related laryngeal muscles during speech.

METHODS

Twenty-four patients undergoing routine PET scans were randomized into two groups to ascertain the relationship between FDG uptake in the laryngeal region and speech. One group was assigned to talk and the other group remained silent during the injection and uptake period of FDG.

RESULTS

FDG uptake in the laryngeal muscles in the scans was correlated with speech. Patients who spoke continually during the uptake period had high-grade FDG uptake, those who spoke intermittently had low-grade uptake and those who remained silent had no detectable increase in FDG uptake in the region of the larynx.

CONCLUSION

The relationship between the degree of laryngeal muscle uptake and speech provides useful information to allow differentiation of physiological from pathological uptake in the neck.

A new method for measurement of erythemal irradiance

A composite system of four dosimeter materials, nalidixic acid (NDA), polysulphone, 8-methoxypsoralen (8-MOP) and phenothiazine, is presented for the passive measurement of the UV spectrum. The properties of the materials were investigated and found to be suitable to allow the materials to be applied in a system to evaluate the UV spectrum. The evaluation of the spectrum reduces by 70% the errors arising when only polysulphone dosimeters are employed to measure the exposure due to a source spectrum that differs from the spectrum they have been calibrated against. Knowledge of the spectrum provides an advantage over the Robertson-Berger meter and polysulphone dosimeters, as the biologically effective exposure for any biological process may be calculated with better than 20% accuracy. The composite system was miniaturised to a size of 3 cm x 3 cm to eliminate errors due to spatial variation of the spectrum and to allow the application at any site on objects with complicated topography in a similar way as polysulphone dosimeters. Unlike the polysulphone dosimeters, the composite system does not require calibration against a specific source of UV in order to maintain a high degree of accuracy in the collected data.

Annual reduction of solar UV exposure to the facial area of outdoor workers in Southeast Queensland by wearing a hat

The total annual exposure to erythemally effective UVR was estimated for average work situations in a high exposure environment, viz, farm workers in Southeast Queensland (27.5 degrees S), and the effect of hat usage was examined. If no sun protection is used, the annual erythema exposures for this group of workers at three facial sites forehead, nose and cheek are 40, 57 and 34 J.cm-2 respectively. If a hat is worn throughout the year, the exposures are reduced to 6, 19 and 20 J.cm-2, respectively. The mean ratio of exposure without the hat to that with the hat (mean protection factor, MPF) was found to be 6 for the forehead, 3 for the nose and 2 for the cheek. The risk of non-melanoma skin cancers without the protection of the hat is estimated to increase by up to 100 times for basal cell carcinomas and 13 times for squamous cell carcinomas for a whole year of exposure.

Measurement of UVA exposure to solar radiation

Exposure to solar UVA (320-400 nm) radiation can damage DNA and lead to skin disorders. Conventional dosimetry using a single piece of polysulfone or diglycol carbonate (CR-39) cannot provide accurate measurement of the biologically effective irradiance for erythema for the UVA waveband. A package employing four dosimeters (polysulfone, nalidixic acid, 8-methoxypsoralen and phenothiazine) has been shown to be effective for use as a spectrum evaluator for evaluating the UVA source spectrum. In Brisbane, on a horizontal position, the spectrum evaluator requires about 5 min exposure in summer and about 20 min in winter. This amounts to about 10 mJ cm-2 of erythemal UV radiation.

The effects of body size and orientation on ultraviolet radiation exposure

A method has been developed for determining the UV and erythemal exposures to the entire body. The difference between the ambient erythemal exposure and that to the body compared to the ambient exposure may be as high as 76%. The height, orientation, and overall height had a minimal effect on the exposure to the body with size, time of day and time of year having a significant effect. The diffuse component of UV to a side of the body ranged from 20% to 41% between different times of the year with different levels of cloud cover. The ratio of the body to the ambient erythemal exposures varied from 0.24 to 0.61, with the time of day and time of year with the smaller value for periods of high solar altitude.

Utility of technetium-99m-MAG3 diuretic renography in the neonatal period

Diuretic renography performed in the neonatal period has been reported to be unreliable in diagnosing obstruction.

METHODS

The scans of 27 neonates (age up to 28 days; mean 17 days) with a total of 53 renal units were reviewed; a renal unit being defined as comprising a kidney and its ureter. All were referred following perinatal ultrasound diagnosis of hydronephrosis or hydroureteronephrosis. The neonates had standard diuretic renography using MAG3 with a frusemide dose of 1 mg/kg followed by another image obtained after gravity-assisted drainage.

RESULTS

There were 17 normal undilated renal units showing excellent diuretic responses with clearance half-times of 0.6-7.7 min. Eighteen renal units were diagnosed as having pelvi-ureteric junction (PUJ) obstruction, with surgical confirmation in all. Eight were diagnosed as unobstructed and of these seven were confirmed nonobstructed by serial imaging using ultrasound and MAG3, but one subsequently had pyeloplasty performed for PUJ obstruction. One unit was indeterminate for PUJ obstruction but had good clearance with gravity-assisted drainage and was shown to be unobstructed on repeat studies. Of nine units diagnosed as having vesico-ureteric junction (VUJ) obstruction, eight had surgical confirmation and one remains of uncertain final diagnosis. Co-existing VUJ obstruction could not be diagnosed in two units with PUJ obstruction because of insufficient radiotracer drainage through the tight stenosis into the ureter.

CONCLUSION

An adequate diuretic response is present in the neonatal period using MAG3 and this allows for reliable diagnosis of obstruction. An unobstructed or indeterminate result necessitates follow-up imaging to ensure obstruction does not develop. Co-existing VUJ obstruction may be missed in a scan showing PUJ obstruction.

A comparison of human- and headform-based measurements of solar ultraviolet B dose

New data on the distribution of solar ultraviolet B (UVB) radiation on the face are presented. Measurements made on human subjects and on rotating headform models are compared, and the effect of altering the orientation of the headform is considered. For a range of postures (standing, sitting, bending, kneeling) a corresponding headform angle (20 degrees, 30 degrees, 40 degrees, 60 degrees respectively) is determined that gives improved agreement with human-based measurements. This suggests that a more realistic simulation of human exposure is achieved by appropriately tilting the model.

Affinity, conservation, and surface exposure of hemopexin-binding proteins in Haemophilus influenzae

Haemophilus influenzae can acquire heme from hemopexin for use as a source of both essential porphyrin and iron. In classical ligand-binding studies, we observed time-dependent, saturable, and displaceable binding of human 125I-labelled hemopexin to intact cells of H. influenzae type b (Hib) strain 760705 grown in an iron-restricted medium. From these experiments, which demonstrate that hemopexin associates with a single class of binding site, the affinities (Kds) and receptor numbers were calculated for heme-hemopexin (Kd, 205 nM; 3,200 receptors per cell) and apohemopexin (Kd, 392 nM; 4,400 receptors per cell). Thus, Hib expresses a specific hemopexin receptor which shows some preference for the heme-protein complex. Affinity chromatography on hemopexin-Sepharose 4B of detergent-solubilized membranes from Hib strain 760705 results in the copurification of three proteins with molecular masses of 57, 38, and 29 kDa. Trypsinization of whole cells of Hib 760705 abolishes hemopexin binding and correlates with the disappearance of the 57-kDa hemopexin-binding protein and appearance of a 52-kDa species which does not bind either hemopexin in ligand blot assays or a monoclonal antibody (MAbT11-30) raised against the 57-kDa protein. From immunoblotting assays and NH2-terminal amino acid sequence analysis, the 38-kDa protein isolated following hemopexin affinity chromatography was identified as the porin protein P2. These data, taken together with the receptor-binding studies which support a single class of hemopexin-binding site, suggest that P2 and the 29-kDa protein function as accessory proteins to the 57-kDa hemopexin-binding protein to facilitate the uptake of heme from receptor-bound hemopexin. To determine whether hemopexin binding and the 57-kDa protein are conserved in Haemophilus strains, whole-cell dot blots and immunoblots of the outer membrane proteins prepared from strains belonging to each of 21 different Hib outer membrane protein subtypes, six nontypeable strains, and five Haemophilus parainfluenzae strains were probed with either hemopexin or MAbT11-30. Only the H. parainfluenzae strains which lack the 57-kDa protein do not bind hemopexin. Since H. influenzae has also been shown to produce a soluble 100-kDa hemopexin-binding protein, cell-free culture supernatants were also examined for the presence of this protein. Apart from Hib 760705 and H. parainfluenzae, the 100-kDa hemopexin-binding protein was detected in all the other Haemophilus strains. The abilities of Hib 760705 to both bind and acquire heme from hemopexin without expressing a 100-kDa soluble hemopexin-binding protein show that in strain 760705, this 100-kDa protein is not essential for the utilization of heme from hemopexin.

An unusual site of heterotopic calcification

Heterotopic calcification may occur following paralysis from spinal cord injury, most commonly affecting the hips. This case demonstrates a bone scan on a T5 paraplegic patient showing an unusual site of heterotopic calcification in the paravertebral musculature in addition to the hip regions. Subsequent CT scanning confirmed the presence of calcification in the erector spinae musculature.

An audit of the management of acute otitis externa in an ENT casualty clinic

The management of acute otitis externa is variable, despite the fact that it is one of the commonest otological emergencies. We formed the impression that many patients attending our ENT casualty clinic with otitis externa were being treated and followed up inappropriately. To test this hypothesis we performed a retrospective pilot study on our practice which revealed a lack of uniformity in the management and follow-up of these patients. And as a result of this, guidelines were developed to improve our management of otitis externa and decrease the number of unnecessary review visits. Our practice was then audited prospectively over a six-month period with the guidelines in place. An improvement in the overall management and a rationalization of follow-up for otitis externa was seen by applying basic audit principles to this common clinical problem.

Identification and characterization of an iron-regulated hemopexin receptor in Haemophilus influenzae type b

Heme can serve Haemophilus influenzae as a source of both essential porphyrin and iron. In extracellular mammalian body fluids neither free heme nor free iron is available, since they are tightly bound to hemopexin and transferrin, respectively. Since H. influenzae grows in the presence of iron-transferrin and heme-hemopexin and is known to express a saturable receptor for transferrin, we investigated the process by which this pathogen acquired heme from hemopexin for use as an iron source. The ability of human and rabbit hemopexin to donate heme as a source of iron to H. influenzae type b strains was demonstrated by plate bioassays. With a dot enzyme assay with biotinylated hemopexin as ligand, H. influenzae bound heme-hemopexin and apo-hemopexin following growth in iron-restricted, but not in iron-sufficient, medium. Competitive binding studies with heme-hemopexin and apo-hemopexin demonstrated saturability of binding. Neither heme, protoporphyrin IX, hemoglobin, nor transferrin blocked the binding of hemopexin to whole cells, demonstrating the specificity of binding. Treatment of whole H. influenzae cells with trypsin abolished binding. Taken together, these observations suggest that H. influenzae type b expresses an outer membrane protein(s) which acts as a receptor for hemopexin and which is regulated by the availability of iron in the growth medium. In iron-restricted media, H. influenzae 706705 and DL42 did not express the 100-kDa hemopexin-binding protein previously reported (M.S. Hanson, S.E. Pelzel, J. Latimer, U. Muller-Eberhard, and E.J. Hansen, Proc. Natl. Acad. Sci. USA 89:1973-1977, 1992). The putative iron-regulated hemopexin receptor was solubilized from cell envelopes of H. influenzae 706705, DL42, and Eagan with the detergent CHAPS (3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulfonate) and isolated by affinity chromatography on heme-hemopexin-Sepharose 4B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins bound to the affinity resin revealed three proteins of 29, 38, and 57 kDa, of which the 57- and 29-kDa proteins bound hemopexin after Western blotting (immunoblotting). A monoclonal antibody to the 57-kDa hemopexin-binding protein of 706705 recognized a 57-kDa protein on Western blots of the cell envelope proteins of 706705, DL42, and Eagan; no reaction was observed with the 100-kDa hemopexin-binding protein of DL42. These data suggest that some H. influenzae strains possess at least two hemopexin receptors, the expression of which is determined by the prevailing growth environment.

Assessment of ventricular septal defect by colour flow mapping

The purpose of this study was to evaluate the usefulness of colour flow mapping (CFM) in the diagnosis and classification of congenital ventricular septal defect (VSD) and in the confirmation of spontaneous and surgical closure. Between August 1988 and March 1990, a total of 102 patients with isolated VSD (82 preoperative and 20 postoperative), age ranging from one day to 14 years, were subjected to 176 echocardiographic examinations. Sequential cross sectional imaging and CFM were the main modalities of assessment with conventional Doppler interrogation for quantitative measurements. In the preoperative group, there were 56 (68.3%) perimembranous (pm) VSD, 14 (17.1%) muscular (m) VSD and 12 (14.6%) doubly committed subarterial (dcsa) VSD. Ventricular septal defect was detected by CFM only in 88.9% of m/VSD, 57.6% of dcsa/VSD and 11.8% of pm/VSD (p less than 0.01). Spontaneous closure rate was highest in m/VSD (28.6%) followed by pm/VSD (8.9%) (p = 0.05). None of the dcsa/VSD closed as assessed by CFM. In the postoperative group, CFM served to quickly confirm complete closure without residual left to right shunt in 20 patients. In addition, CFM was useful in the assessment of haemodynamics and flow directed Doppler interrogation. Hence, CFM is a useful adjunct to cross sectional imaging in the assessment of children with isolated VSD.

Decreased inflammatory responsiveness of hypophysectomized rats to heat is reversed by a corticotropin-releasing factor (CRF) antagonist

Hypophysectomy, but not adrenalectomy, decreased (relative to sham-operated controls) the swelling and Evans blue dye extravasation responses of the anesthetized rat's pawskin to thermal injury. alpha-Helical CRF (9-41), a synthetic competitive antagonist of corticotropin-releasing factor (CRF) on isolated pituitary cells, did not affect in sham-operated rats the swelling response after immersion of the paw in 58 degrees C water for 30 s. Swelling was measured over a 1 h period using the fluid displacement method for quantifying paw volume. But, when alpha-helical CRF (9-41) was injected 92 micrograms/kg i.v. 10 min before or immediately after heat exposure, it both attenuated and reversed the insensitive state produced by hypophysectomy: that is, the swelling response reappeared. Under the same test conditions, naloxone hydrochloride, an opioid antagonist, was ineffective. The results suggest that hypophysectomy may induce a condition whereby endogenous CRF or CRF-like peptides may act as an anti-inflammatory agent.

Percutaneous transluminal balloon valvuloplasty: the treatment of choice for congenital valvar pulmonary stenosis

Forty-eight children with suspected isolated pulmonary valvar stenosis were evaluated clinically and echocardiographically between January 1987 and December 1988. Fourteen patients with significant transpulmonary peak systolic pressure gradient greater than 30 mmHg on continuous-wave Doppler interrogation were subjected to right heart catheterisation. Percutaneous transluminal balloon valvuloplasty was performed in 11 of these patients with peak systolic pressure gradient than 40 mmHg across the pulmonary valve at cardiac catheterisation. Satisfactory reduction of systolic right ventricular pressure (110 +/- 43 to 46 +/- 17 mmHg, p less than 0.001) and peak systolic pressure gradient across pulmonary valve (92 +/- 44 to 27 +/- 16 mmHg, p less than 0.001), were achieved in all cases. The reduction of peak systolic pressure gradient (64 +/- 37 mmHg, range = 29-158 mmHg), was positively correlated with the initial right ventricular systolic pressure (r = 0.92, p less than 0.0002). There was no significant complication in this series and all patients were discharged the day after the procedure. Percutaneous transluminal balloon valvuloplasty is effective and safe. It should be the treatment of choice for significant valvar pulmonary stenosis in children.

[Management of traumatic injuries of the colon]

We have reviewed our experience with penetrating lesions of the colon at the Santo Tomás Hospital. Good results were obtained with immediate suture of the lesions without need for colostomy when favorable conditions permit.

Knee, ankle, and foot problems in the preadolescent and adolescent athlete

Children are the nearest thing in the human race to tadpoles in that they have tremendous powers of healing and regeneration. It should be remembered that they are subject to overstress injuries, more so than middle-aged adults. Precautions should be taken and the proper radiographs made when any swelling or tenderness occurs about a joint because of the tendency of children to develop injuries involving the growing centers of bone.

Challenge exposure of cattle vaccinated with a chemically altered strain of Pasteurella haemolytica

Calves vaccinated with a chemically altered strain of Pasteurella haemolytica and their nonvaccinated controls were challenge exposed intranasally with the Cooper strain of infectious bovine rhinotracheitis virus. Five days later, the calves were challenge exposed intratracheally with the P haemolytica type A1. Calves that had been vaccinated with large, medium, or small doses of the chemically altered vaccinal strain of P haemolytica had various degrees of resistance to the experimental challenge exposure. Nonvaccinated animals developed severe respiratory tract disease and pneumonia after challenge exposure.

Cross-protection by a chemically altered vaccinal strain of Pasteurella multocida in mice and hamsters

A chemically altered type A strain of Pasteurella multocida was used to vaccinate mice and hamsters. The vaccinated animals were challenge exposed with type A, B, and E isolated of P multocida. A degree of protection was afforded the vaccinated animals against homologous and heterologous challenge-exposure strains.

A study of the interaction of practolol with acetylcholine, histamine, serotonin and bradykinin in the guinea-pig, and with bean-sprout juice in the mouse

1. The interactions of practolol with acetylcholine, histamine, serotonin and bradykinin were studied on the trachea and lung of the guinea-pig, an animal whose sensitivity to bronchoactive endogens is known to be similar to that of human asthmatic bronchi. 2. Practolol, like propranolol, potentiated the action of the first three agonists mentioned above, but, unlike propranolol, it did not potentiate the bronchospastic effect of bradykinin. 3. Practolol, in fact, antagonized the action of bradykinin, but this effect was unlike that produced by nonsteroidal anti-inflammatory drugs. 4. The possibility that beta-adrenoreceptor antagonists might show adverse interactions with certain foodstuffs was investigated, an is discussed. 5. It is suggested that the feasibility of the continued use of practolol (or the newer cardioselective beta-blockers) in asthmatics necessarily depends on the type of allergic reaction involved, and so it is not possible to generalize. Any drug or food that might cause a bronchospastic effect synergistically in the presence of a beta- adrenoreceptor antagonist, even a cardioselective one, should be regarded with suspicion.

Fermentation of L-aspartate by a saccharolytic strain of Bacteroides melaninogenicus

Resting cells of Bacteroides melaninogenicus fermented L-[14C]aspartate as a single substrate. The 14C-labeled products included succinate, acetate, CO2, oxaloacetate, formate, malate, glycine, alanine, and fumarate in the relative percentages 68, 15, 9.9, 2.7, 1.8, 1.0, 0.7, 0.5, and 0.06, respectively, based on the total counts per minute of the L-[14C]aspartate fermented. Ammonia was produced in high amounts, indicating that 96% of the L-aspartate fermented was deaminated. These data suggest that L-aspartate is mainly being reduced through a number of intermediate reactions involving enzymes of the tricarboxylic acid cycle to succinate. L-[14C]asparagine was also fermented by resting cells of B. melaninogenicus to form L-aspartate, which was subsequently, but less actively, fermented.

Influence of amino acids on the growth of Bacteroides melaninogenicus

Addition of individual amino acids to a Trypticase-yeast extract-hemin medium affected growth rates and final yields of an asaccharolytic strain and a saccharolytic strain of Bacteroides melaninogenicus. L-Aspartate or L-asparagine produced maximal growth enhancement for both strains. L-[14C]aspartate was fermented by resting cells of the asaccharolytic strain. L-Cysteine or L-serine also enhanced growth for the saccharolytic strain. However, growth of the saccharolytic strain was inhibited by L-lysine, L-glutamate, L-glutamine, L-isoleucine, L-leucine, and L-proline; growth of the asaccharolytic strain was inhibited by DL-valine and L-serine. Both strains were inhibited by L-histidine, DL-methionine, L-tryptophan, L-arginine, and glycine.