Synthesis of 7200 small molecules based on a substructural analysis of the histone deacetylase inhibitors trichostatin and trapoxin

Seventy-two hundred potential inhibitors of the histone deacetylase (HDAC) enzyme family, based on a 1,3-dioxane diversity structure, were synthesized on polystyrene macrobeads. The compounds were arrayed for biological assays in a "one bead-one stock solution" format. Metal-chelating functional groups were used to direct the 1,3-dioxanes to HDAC enzymes, which are zinc hydrolases. Representative structures from this library were tested for inhibitory activity and the 1,3-dioxane structure was shown to be compatible with HDAC inhibition. [structure: see text]

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.

QTL and candidate genes phytoene synthase and zeta-carotene desaturase associated with the accumulation of carotenoids in maize

Carotenoids are a class of fat-soluble antioxidant vitamin compounds present in maize ( Zea mays L.) that may provide health benefits to animals or humans. Four carotenoid compounds are predominant in maize grain: beta-carotene, beta-cryptoxanthin, zeaxanthin, and lutein. Although beta-carotene has the highest pro-vitamin A activity, it is present in a relatively low concentration in maize kernels. We set out to identify quantitative trait loci (QTL) affecting carotenoid accumulation in maize kernels. Two sets of segregating families were evaluated-a set of F2:3 lines derived from a cross of W64a x A632, and their testcross progeny with AE335. Molecular markers were evaluated on the F2:3 lines and a genetic linkage map created. High-performance liquid chromatography was performed to measure beta-carotene, beta-cryptoxanthin, zeaxanthin, and lutein on both sets of materials. Composite interval mapping identified chromosome regions with QTL for one or more individual carotenoids in the per se and testcross progenies. Notably QTL in the per se population map to regions with candidate genes, yellow 1 and viviparous 9, which may be responsible for quantitative variation in carotenoids. The yellow 1 gene maps to chromosome six and is associated with phytoene synthase, the enzyme catalyzing the first dedicated step in the carotenoid biosynthetic pathway. The viviparous 9 gene maps to chromosome seven and is associated with zeta-carotene desaturase, an enzyme catalyzing an early step in the carotenoid biosynthetic pathway. If the QTL identified in this study are confirmed, particularly those associated with candidates genes, they could be used in an efficient marker-assisted selection program to facilitate increasing levels of carotenoids in maize grain.

Prediction of the rate of decline in FEV(1) in smokers using quantitative Computed Tomography

BACKGROUND

A study was undertaken to determine if quantitative CT estimates of lung parenchymal overinflation and airway dimensions in smokers with a normal forced expiratory volume in 1 s (FEV(1)) can predict the rapid decline in FEV(1) that leads to chronic obstructive pulmonary disease (COPD).

METHODS

Study participants (n = 143; age 45-72 years; 54% male) were part of a lung cancer screening trial, had a smoking history of >30 pack years and a normal FEV(1) and FEV(1)/forced vital capacity (FVC) at baseline (mean (SD) FEV(1) 99.4 (12.8)%, range 80.2-140.7%; mean (SD) FEV(1)/FVC 77.9 (4.4), range 70.0-88.0%). An inspiratory multislice CT scan was acquired for each subject at baseline. Custom software was used to measure airway lumen and wall dimensions; the percentage of the lung inflated beyond a predicted maximal lung inflation, the low attenuation lung area with an x ray attenuation lower than -950 HU and the size distribution of the overinflated lung areas and the low attenuation area were described using a cluster analysis. Multiple regression analysis was used to test the hypothesis that these CT measurements combined with other baseline characteristics might identify those who would develop an excessive annual decline in FEV(1).

RESULTS

The mean (SD) annual change in FEV(1) was -2.3 (4.7)% predicted (range -23.0% to +8.3%). Multiple regression analysis revealed that the annual change in FEV(1)%predicted was significantly associated with baseline percentage overinflated lung area measured on quantitative CT, FEV(1)% predicted, FEV(1)/FVC and gender.

CONCLUSION

Quantitative CT scan evidence of overinflation of the lung predicts a rapid annual decline in FEV(1) in smokers with normal FEV(1).

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.

Split--pool synthesis of 1,3-dioxanes leading to arrayed stock solutions of single compounds sufficient for multiple phenotypic and protein-binding assays

Diversity-oriented organic synthesis offers the promise of advancing chemical genetics, where small molecules are used to explore biology. While the split--pool synthetic method is theoretically the most effective approach for the production of large collections of small molecules, it has not been widely adopted due to numerous technical and analytical hurdles. We have developed a split--pool synthesis leading to an array of stock solutions of single 1,3-dioxanes. The quantities of compounds are sufficient for hundreds of phenotypic and protein-binding assays. The average concentration of these stock solutions derived from a single synthesis bead was determined to be 5.4 mM in 5 microL of DMSO. A mass spectrometric strategy to identify the structure of molecules from a split--pool synthesis was shown to be highly accurate. Individual members of the 1,3-dioxane library have activity in a variety of phenotypic and protein-binding assays. The procedure developed in this study allows many assays to be performed with compounds derived from individual synthesis beads. The synthetic compounds identified in these assays should serve as useful probes of cellular and organismal processes.

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.

Intracytoplasmic sperm injection increased fertilization and good-quality embryo formation in patients with non-male factor indications for in vitro fertilization: a prospective randomized study

OBJECTIVE

To compare the fertilization rate and formation of good-quality embryos with conventional IVF and ICSI in patients with non-male factor infertility.

DESIGN

Prospective controlled study.

SETTING

Infertility clinic.

PATIENT(S)

Thirty-five patients with non-male factor infertility.

INTERVENTION(S)

Retrieved sibling oocytes were randomly assigned to conventional IVF or ICSI. Of sibling oocytes assigned to ICSI, only metaphase II oocytes were injected with sperm.

MAIN OUTCOME MEASURE(S)

Fertilization rate and formation of good-quality embryos per retrieved oocyte.

RESULT(S)

Per retrieved oocyte, ICSI resulted in better fertilization rate compared with conventional IVF (71.3% [134 of 188] vs. 57.2% [107 of 187]). Per retrieved oocyte, ICSI also resulted in better formation of good-quality embryos at 48 hours after retrieval compared with conventional IVF (64.4% [121 of 188] vs. 47.1% [88 of 187]).

CONCLUSION(S)

In IVF patients with non-male factor infertility, subjecting some sibling oocytes to ICSI increased the fertilization rate and formation of good-quality embryos per retrieved oocyte. It also avoided the problem of total fertilization failure in almost all cases.

Enhancement of vitamin E levels in corn

Vitamin E is the common name that describes eight naturally occurring compounds possessing alpha-tocopherol activity. These eight vitamin E compounds are collectively termed tocols, and all have antioxidant activity. There is natural variation among different corn breeding lines for levels of tocols. The two predominant isomers present in corn grain are gamma-tocopherol and alpha-tocopherol. Alpha-tocopherol is considered more desirable for human and animal consumption because it has higher biological activity than gamma-tocopherol. Most corn breeding lines naturally have much more gamma-tocopherol than alpha-tocopherol. Therefore a breeding goal is to increase levels of alpha-tocopherol relative to gamma-tocopherol. However, recent research suggests that gamma-tocopherol and compounds metabolized from it have properties important to human health that are unique from properties of alpha-tocopherol. Therefore it may be desirable to not only increase levels of alpha-tocopherol in corn grain, but also levels of gamma-tocopherol. Determination of levels of tocopherols in corn grain is very laborious, requires HPLC analysis and is too time consuming for use in routine commercial corn breeding programs. Therefore we are performing biotechnology enabled molecular marker mapping of chromosomal regions with genes that control levels and ratios of alpha- and gamma-tocopherol. Breeders can use molecular markers we have identified to expediently select for desirable alleles of genes that will improve levels of alpha- and gamma-tocopherol in corn grain, without having to perform laborious HPLC assays. Another biotechnology strategy we have initiated is genetic transformation of corn with the gamma-tocopherol methyl transferase gene to enhance conversion of gamma-tocopherol to alpha-tocopherol and thus increase levels of alpha-tocopherol. This transgenic strategy has been demonstrated in the model plant Arabidopsis, and we are now applying this approach to corn.

Diffuse component of solar ultraviolet radiation in tree shade

The first set of quantitative data of diffuse erythemal UV and UV-A radiation in tree shade at a sub-tropical Southern Hemisphere latitude is presented. Over the summer, approximately 60% of the erythemal UV radiation in tree shade is due to the diffuse component. Similarly, approximately 56% of the UV-A radiation in tree shade is due to the diffuse component. In tree shade these diffuse UV percentages are relatively constant from the morning to noon to afternoon periods. In comparison, in full sun, there is a decrease in the percentage of diffuse UV from morning to noon to afternoon. The exposures to diffuse UV on a horizontal plane in tree shade between 9:00 EST and 15:00 EST are of the order of 4 MED (minimum erythemal dose) and 14 J cm(-2) for erythemal UV and UV-A, respectively. The high diffuse UV component in the shade may result in high UV exposures not only to unprotected parts of the body on a horizontal plane, but also in equally high UV irradiances to parts of the body, including the eyes and face, that are not UV protected.

[11C]Methionine positron emission tomography for patients with persistent or recurrent hyperparathyroidism after surgery

OBJECTIVE

Reoperation in patients with recurrent hyperparathyroidism usually requires localisation of abnormal glands. Current imaging techniques are not always successful in this group of patients. An evaluation of [11C]methionine positron emission tomography (PET) has been made to assess the ability of the technique to localise abnormal glands in patients with hyperparathyroidism after previous surgery.

SUBJECTS AND METHODS

Eight patients (five with primary, and three with tertiary hyperparathyroidism) who had undergone one to three previous surgical explorations were studied. [11C]methionine PET scans of the neck and mediastinum were performed in all patients. All had recent technetium-99m (99mTc)-labelled sestamibi (n = 7) or thallium-201 (201Tl)/99mTc subtraction (n = 1) parathyroid scans available for comparison. Subsequent surgical correlation was available in all cases.

RESULTS

[11C]methionine PET correctly located an abnormal site of uptake in all five patients with primary hyperparathyroidism compared with only one when conventional nuclear medicine methods were used. In the patients with tertiary hyperparathyroidism, [11C]methionine PET correctly located one, confirmed the absence of cervical or mediastinal abnormality in a patient with an autotransplanted forearm autonomous gland, and failed to demonstrate an abnormality in a third. 99mTc-labelled sestamibi scans were negative in all three patients.

CONCLUSION

[11C]methionine PET correctly locates abnormal parathyroid glands in the majority of patients with persistent or recurrent hyperparathyroidism after surgery in whom conventional non-invasive nuclear medicine imaging has failed.

Annual occupational exposure to ultraviolet radiation in central Queensland

The purpose of this study was to determine annual occupational exposure to UV radiation by measurement and derive ambient exposure fractions for an entire year that could be applied in the human exposure model. Using polysulphone the daily occupational erythema effective solar ultraviolet radiation exposure at selected body sites of Australia Post mail delivery personnel and physical education teachers were measured over an 18-mo period on a daily basis in the Rockhampton (lat. 23.5 degrees S) region. The daily exposures were summed to estimate an annual exposure for these occupations in this region. For the Australia Post mail delivery personnel, who had very little change to the posture or route during delivery, the annual mean estimates of exposure to erythema effective solar irradiance for the chest, hands, and back were in the range of 192+/-27 kJ m(-2), 388+/-45 kJ m(-2), and 283+/-32 kJ m(-2), respectively. Physical education teachers had varied duties on a day-to-day basis and many changes in their posture and outdoor locations where the exposure occurred. Their annual mean exposure on the vertex (hat), chest, shoulder, thigh, and back were in the range 340+/-71 kJ m(-2), 140+/-28 kJ m(-2), 180+/-40 kJ m(-2), 129+/-24 kJ m(-2), and 212+/-42 kJ m(-2), respectively. The annual exposure range for erythema effective solar irradiance at different body sites during the experimental period was between 120 and 440 kJ m(-2) for the two occupational groups. These exposures greatly exceed the National Health and Medical Research Council occupational standard limit of 30 J m(-2) for daily exposure, which indicates the need for additional protective measures. The ambient exposure was also measured and used to compute ambient exposure fractions for the different body sites over an entire year, which are useful for model calculations on human exposure and assess increase in risk of n on melanoma skin cancer.

Outcome of surgical closure of doubly committed subarterial ventricular septal defect

BACKGROUND

From 1986 to March 1997, 128 patients diagnosed to have doubly committed subarterial ventricular septal defects (VSD) were reviewed. Patients with aortic regurgitation (AR), and aortic valve (AV) deformity or a large left-to-right shunt across the VSD were offered operation. Forty-five patients (27 men, 18 women) agreed to surgical closure of their VSDs.

METHODS

Thirty-eight patients had VSD closure alone, and 7 had an additional AV repair. Other associated defects corrected at operation were closure of atrial septal defects, closure of other ventricular septal defects, ligation of patent ductus arteriosus, and repair of ruptured sinus Valsalva aneurysm.

RESULTS

There was no mortality nor major morbidity associated with operation. In the 26 patients with AR and AV deformity preoperatively, valve repair was performed in 6 patients. The condition of AR improved in 4, and remained unchanged in 22 patients. In the 10 patients with a deformity of the AV and no AR preoperatively, the condition remained unchanged in 5 patients, from whom 1 had valve operation, but progressed in 5 patients postoperatively at a mean follow-up of 6.4 years. In 9 patients with no deformity of the AV and no AR preoperatively, there was no postoperative AR and no progress of valve deformity.

CONCLUSIONS

Excellent results were obtained with VSD closure and AV repair. Surgical closure of VSD, if performed before the onset of AV deformity, may prevent progressive AR. If AV repair is performed after the onset of AV deformity, progressive AR may not always be prevented.

Computed tomographic estimation of lung dimensions throughout the growth period

The aim of the current study was to use computed tomography (CT) to estimate airway wall and lumen, and arterial and parenchyma dimensions in children throughout the growth period, and to provide normative data to study alterations caused by pulmonary disease. Clinical CT scans reported as normal that were performed in children for nonpulmonary and noncardiac reasons were analysed for lung weight, gas volume, lung expansion, lung surface/volume ratio, airway wall area, airway lumen area, airway lumen perimeter, arterial area and airway surface length/area ratio. The age range of the 50 subjects was 0-17.2 yrs. The data showed only little increase in lung expansion throughout childhood (n = 32). There was substantial variability in lung expansion between subjects. Airway wall and lumen and arterial area were exponentially associated with subjects' height (n = 50). Airway surface length/area ratio was linearly associated to alveolar surface/volume ratio. The data from the current study provide normative computed tomography estimates of airway wall and lumen, and arterial and parenchyma dimensions throughout the growth period that may be useful for the study of alterations in disease.

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.

Exposure of human oocytes to endometrioma fluid does not alter fertilization or early embryo development

BACKGROUND

Extensive endometriosis causes a mechanical disturbance in the pelvis leading to obstructive-type infertility. However, minimal or mild endometriosis is suspected to cause infertility, possibly through a humoral agent. Previous studies reported the presence of a factor in the serum of patients with endometriosis which reduced fertilization and early embryo formation in a rat IVF model.

METHODS

In the present article, we report a comparison of oocytes exposed to endometrioma fluid and oocytes not exposed (controls) in the context of a human IVF setting. We have been in the practice of aspirating oocytes into prewarmed 60-ml syringes containing culture medium. We have shown previously that this technique reduces the length of oocyte retrieval without compromising success. In 14 women undergoing oocyte retrieval, we inadvertently entered an endometrioma. This resulted in retrieved oocytes that were either exposed or not exposed to endometrioma fluid.

RESULTS

In contrast to previous reports, we found no difference in fertilization or early embryo development between the two groups. The fertilization rate for oocytes exposed to an endometrioma was 60%, versus 56% for controls. The good-quality embryo formation rate for oocytes exposed to an endometrioma was 45%, versus 46% for controls.

Effects of high sound levels on responses to the vowel "eh" in cat auditory nerve

The vowel "eh" was used to study auditory-nerve responses at high sound levels (60-110 dB). By changing the playback sampling rate of the stimulus, the second formant (F2) frequency was set at best frequency (BF) for fibers with BFs between 1 and 3 kHz. For vowel stimuli, auditory-nerve fibers tend to phase-lock to the formant component nearest the fiber's BF. The responses of fibers with BFs near F2 are captured by the F2 component, meaning that fibers respond as if the stimulus consisted only of the F2 component. These narrowband responses are seen up to levels of 80-100 dB, above which a response to F1 emerges. The F1 response grows, at the expense of the F2 response, and is dominant at the highest levels. The level at which the F1 response appears is BF dependent and is higher at lower BFs. This effect appears to be suppression of the F2 response by F1. At levels near 100 dB, a component 1/component 2 transition is observed. All components of the vowel undergo the transition simultaneously, as judged by the 180 degrees phase inversion that occurs at the C2 transition. Above the C2 threshold, a broadband response to many components of the vowel is observed. These results demonstrate that the neural representation of speech in normal ears is degraded at high sound levels, such as those used in hearing aids.

Evaluation of differences in ultraviolet exposure during weekend and weekday activities

The weekday UV exposures to anatomical sites were evaluated for outdoor workers, home workers, adolescents, indoor workers, school staff and students in south-east Queensland, Australia. Additionally, the UV exposures at weekends of school staff, school students, indoor workers and outdoor workers were evaluated. The weekday exposures per day ranged from 1.0 to 11.0 SED for winter to summer respectively. During spring, the ratios of the personal exposures divided by the ambient exposures at the weekend to the personal exposures divided by the ambient exposures on the weekdays to the neck, hand and left arm were at least 3.4, 2.0 and 0.67 for the indoor workers, school staff and students and outdoor workers respectively. The same ratios for the erythemal UV exposures over the year, estimated from the exposures on four days in each of the four seasons, were at least 2.3 for the school staff and at least 1.3 for the 13 to 19 year old school students. These results reinforce the importance of targeting prevention programmes to both weekend and weekday exposures.

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.

Personal exposure distribution of solar erythemal ultraviolet radiation in tree shade over summer

The personal radiant exposure distribution of solar erythemal UV in tree shade for an upright posture was measured, with measurements over the whole summer for a total of 17 trees. For each tree, the personal radiant exposure distribution was measured for both the morning and afternoon periods. The exposure ratios averaged over all the trees and over the morning and afternoon periods ranged from 0.16 to 0.49 for the different anatomical sites. A numerical model was employed to estimate the UV radiant exposure to humans in tree shade over the entire summer. The body sites with the higher exposure ratios in the tree shade were the vertex of the head, shoulders and forearms with radiant exposures over the summer of 1300 MED to the vertex of the head and 1100 MED to the shoulders and forearms. These radiant exposures in the shade are substantially higher than the ambient erythemal UV measured in full sun on a horizontal plane over a full summer at a more temperate northern hemisphere latitude. The average radiant exposures per day to each anatomical site for a complete day in the tree shade ranged from 4.6 to 14.6 MED. This research has provided new data that is essential to quantify human UV exposure during outdoor activities.

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.

Effect of childhood and adolescent ultraviolet exposures on cumulative exposure in South East Queensland schools

Quantitative estimates of the childhood and adolescent erythemal ultraviolet (UV) exposure received in South East Queensland schools are provided in this paper for age groups 0 to 6, 7 to 12 and 13 to 19 years. For the neck, hand and lower arm, sites of high UV exposure that are generally not covered by clothing, 13 to 19 year olds received the highest exposure of the three age groups, followed by 7 to 12 year olds. Exposure for 13 to 19 year olds contributed up to 44% of cumulative exposure to 20 years of age, and exposures for the 7 to 12 year olds contributed up to 31%. If the annual UV exposure for these two age groups were reduced to the average of all the age groups, cumulative erythemal UV exposure from 0 to 20 years would be reduced by up to 16%. On the other hand, if mothers can protect their babies by reducing the level of annual exposure to 30% of the annual UV exposure of the 7 to 12 year olds for the first four years then cumulative exposure to UV to age 20 would be reduced by up to 19%. These data confirm the importance of targeting young age groups in public campaigns for sun protection.

Bone mineral density in adolescent females with recently diagnosed anorexia nervosa

Anorexia nervosa (AN) can lead to osteoporosis and fractures.

OBJECTIVE

This study evaluated adolescent females with AN diagnosed within the previous 12 months to determine whether there is bone mass reduction and to investigate relationships between nutritional indices (weight, body mass index [BMI], lean mass, fat mass, and percentage fat) and total body (TB) and lumbar spine (LS) bone mineral densities (BMD) and content (BMC).

METHOD

TB and LS BMD and BMC and body composition were measured in 24 adolescent females with AN.

RESULTS

There was no significant reduction in TB or LS BMD. Regression analysis shows significant correlation (p < 0.001) between lean mass and TB BMD (r = +0.83), TB BMC (r = +0.92), LS BMD (r = +0.81), and LS BMC (r = +0.92). There was also a significant relationship between weight percentile and LS BMD z score (p < 0.005; r = +0.60).

DISCUSSION

Adolescent females with early AN do not appear to have reduced bone mass. Lean mass is correlated to BMD and BMC.

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.