A 3D approach to model the taper of irregular tree stems: making plots biomass estimates comparable in tropical forests.

In tropical forests, the high proportion of trees showing irregularities at the stem base complicates forest monitoring. For example, in the presence of buttresses, the height of the point of measurement (HPOM ) of the stem diameter (DPOM ) is raised from 1.3 m, the standard breast height, up to a regular part of the stem. While DPOM is the most important predictor for tree aboveground biomass (AGB) estimates, the lack of harmonized HPOM for irregular trees in forest inventory increases the uncertainty in plot-level AGB stock and stock change estimates. In this study, we gathered an original non-destructive three-dimensional (3D) data set collected with terrestrial laser scanning and close range terrestrial photogrammetry tools in three sites in central Africa. For the 228 irregularly shaped stems sampled, we developed a set of taper models to harmonize HPOM by predicting the equivalent diameter at breast height (DBH') from a DPOM measured at any height. We analyzed the effect of using DBH' on tree-level and plot-level AGB estimates. To do so, we used destructive AGB data for 140 trees and forest inventory data from eight 1-ha plots in the Republic of Congo. Our results showed that our best simple taper model predicts DBH' with a relative mean absolute error of 3.7% (R2 = 0.98) over a wide DPOM range of 17-249 cm. Based on destructive AGB data, we found that the AGB allometric model calibrated with harmonized HPOM data was more accurate than the conventional local and pantropical models. At the plot level, the comparison of AGB stock estimates with and without HPOM harmonization showed an increasing divergence with the increasing share of irregular stems (up to -15%). The harmonization procedure developed in this study could be implemented as a standard practice for AGB monitoring in tropical forests as no additional forest inventory measurements is required. This would probably lead to important revisions of the AGB stock estimates in regions having a large number of irregular tree stems and increase their carbon sink estimates. The growing use of three-dimensional (3D) data offers new opportunities to extend our approach and further develop general taper models in other tropical regions.

The prevalence of burnout among oncology professionals: oncologists are at risk of developing burnout.

OBJECTIVE: International research shows that oncology staff suffers more from burnout than other healthcare professionals. Burnout is common among oncologists. The prevalence of emotional exhaustion, depersonalization, and low personal accomplishment appears to be significantly higher among physicians. Detecting burnout is highly relevant, because it affects the personal well-being and quality of life of the healthcare professional. A national study on the prevalence of burnout in oncology was never conducted in Flanders (Dutch-speaking part of Belgium). METHODS: The Cédric Hèle institute spread anonymous questionnaires among 923 healthcare workers in oncology (physicians, social workers, psychologists, nurses, and specialist-nurses) in Flanders. The questionnaire consisted of two parts. The first part contained questions concerning demographic and job features. The second part included the Dutch version of the Maslach Burnout Inventory. RESULTS: Five hundred and fifty subjects participated in the survey (response rate of 59.5%). Of the medical oncologists, 51.2% suffered from emotional exhaustion, 31.8% from depersonalization, and 6.8% from a lack of personal accomplishment. Multivariate analysis of variance suggested a significantly elevated level of emotional exhaustion and depersonalization in oncologists compared with other professionals. Logistic regression indicated that the following variables have predictive value on risk of burnout: gender, profession, and combining work in a university hospital with work in a private hospital. CONCLUSION: The CHi research showed a significantly increased level of burnout-components in professionals working in oncology, especially in medical oncologists. These results should have an impact on the daily clinic of oncology, and could be guidance for further research.

The 'Distress Barometer': validation of method of combining the Distress Thermometer with a rated complaint scale.

OBJECTIVE: Screening instruments may enhance the clinician's ability to detect elevated levels of distress in cancer patients, but these are often neither suitable nor effective for the routine of daily care for cancer patients. The newly developed Distress Barometer (DB) was intended to provide medical doctors with a convenient tool to interpret 'at single glance' the nature and the intensity of distress in ambulatory cancer patients. The DB, i.e. a combination of the Distress Thermometer (DT) and a new tool, the Colored Complaint Scale was developed to improve the specificity of distress screening without decreasing the sensitivity of the Distress Thermometer. METHODS: Distress was screened in a sample of 538 out-patients, using the Hospital Anxiety and Depression Scale (HADS) and the new Distress Barometer (DB). RESULTS: The results confirm the validity of the Dutch version of the DT against the HADS as standard measure. In addition, it was found that the overall accuracy of the new DB was higher, with a sensitivity of 0.79 and a specificity of 0.81. CONCLUSION: These results indicate that the Distress Barometer, which is convenient for both patients and doctors, can be used as an acceptable, brief and sufficiently accurate method for detecting distress in cancer patients.

TRF2 inhibition promotes anchorage-independent growth of telomerase-positive human fibroblasts.

Although telomere instability is observed in human tumors and is associated with the development of cancers in mice, it has yet to be established that it can contribute to the malignant transformation of human cells. We show here that in checkpoint-compromised telomerase-positive human fibroblasts an episode of TRF2 inhibition promotes heritable changes that increase the ability to grow in soft agar, but not tumor growth in nude mice. This transforming activity is associated to a burst of telomere instability but is independent of an altered control of telomere length. Moreover, it cannot be recapitulated by an increase in chromosome breaks induced by an exposure to gamma-radiations. Since it can be revealed in the context of telomerase-proficient human cells, telomere dysfunction might contribute to cancer progression even at late stages of the oncogenesis process, after the telomerase reactivation step.

Vital marking of articular chondrocytes by retroviral infection using green fluorescence protein.

OBJECTIVE: One of the main open questions in chondrocyte transplantation is the fate of the implanted cells in vivo. We intended to establish prerequisites for such studies in animal models and to show the feasibility of this approach in rabbits. Isolated articular chondrocytes were retrovirally marked using green fluorescence protein (GFP) as a cell-specific marker in order to allow an in vivo follow-up of these cells. METHODS: Chondrocytes from rabbits, sheep, cattle and humans were isolated and infected with murine leukemia virus-derived retroviruses carrying the GFP gene. The influence of the host range of three packaging cell lines (PA317, PT67, PG13), start cell concentrations, number of cell passages and number of infection cycles on the efficiency of infection was investigated. Stability of GFP expression was followed by FACS analysis, confocal imaging and fluorescence microscopy. For in vivo follow-up of GFP expression we used marked allogeneic chondrocyte populations grown on scaffold material and implanted them into full-thickness defects in knee joints of rabbits. RESULTS: Retroviruses from all three packaging cell lines were able to infect rabbit and human chondrocytes, whereas only retroviruses released from PG13 cells were able to infect sheep and bovine chondrocytes efficiently. Optimization of the infection with these viruses resulted in efficiencies of 60-90% GFP-expressing chondrocytes. Populations of 100% marked chondrocytes were obtained by cell sorting. GFP expression stability of such marked chondrocyte populations was followed in monolayer culture and in 3-D culture on different scaffold materials. The expression of GFP was stable on all tested materials for at least 4 weeks. In monolayer culture GFP expression was stable for more than 8 months. In vivo, we observed stable GFP expression in the transplants during a four-week time course. CONCLUSION: Retroviral GFP gene transfer led to long-term expression in chondrocytes from rabbits, sheep, cattle and humans. Transgene expression and the number of implanted chondrocytes remain stable for at least 4 weeks in vivo. This method permits a rapid monitoring of chondrocytes and provides a basis for following the fate of these cells in vivo.

Attitudes and knowledge about cancer pain in Flanders. The educational effect of workshops regarding pain and symptom control.

Despite international agreements and recommendations regarding cancer pain therapy, the effectiveness of pain treatment is still a major problem even in Western countries. Part of the problem is that physicians and nurses often lack knowledge of methods for the assessment and treatment of cancer pain and may have many rigid beliefs and attitudes. This study investigated the misconceptions of physicians and nurses that play a role in the undertreatment of pain in Flanders (Belgium). We approached 197 health care workers who participated in the pain and symptom control education sessions organized by the Federation Palliative Care Flanders, and asked them to complete a questionnaire both before and after the sessions. The impact of the education sessions on their knowledge and beliefs regarding the management of cancer pain was substantial. Methods of reaching the target groups that do not feel the need for further education are discussed.

Plant CDC2 is not only targeted to the pre-prophase band, but also co-localizes with the spindle, phragmoplast, and chromosomes.

A polyclonal antiserum against the p34cdc2 homologue of Arabidopsis thaliana, CDC2aAt, was used in parallel with a polyclonal antiserum against the PSTAIRE motif to study the subcellular localization of CDC2 during the cell cycle of isolated root tip cells of Medicago sativa. During interphase, CDC2 was located in the nucleus and in the cytoplasm. The cytoplasmic localization persisted during the complete cell cycle, whereas the nuclear signal disappeared at nuclear envelope breakdown. At the beginning of anaphase, the anti-CDC2aAt antibody transiently co-localized with condensed chromosomes. The chromosomal co-localization disappeared as anaphase continued and remained excluded from the separated chromosomes until cytokinesis, when CDC2 re-located to the newly forming nuclei. We also observed a co-localization of CDC2 with three microtubular structures, the pre-prophase band, the spindle, and the phragmoplast.

Sensitivity and positive predictive value of clinical signs of hypogonadism in elderly men.

One hundred three ambulatory elderly men had serum free testosterone (FT) assessed as part of a study of bone loss. The FT was analyzed using radioimmunoassay. Each participant was questioned regarding the presence of erections adequate for sexual activity and the presence of sexual desire. Each was examined for decreased axillary and pubic hair. A FT of less than 9.0 pg/mL was found in eight subjects. The sensitivity of the clinical predictors as an indicator of a low FT value ranged from 43% to 86%, while positive predictive value ranged from 12% to 19%. The abnormal clinical signs and symptoms investigated in this study obviously have mechanisms in addition to hypogonadism. A history of adequate erections ruled out a low FT value in all but 1 of 44 cases.

Lack of association between free testosterone and bone density separate from age in elderly males.

It is unclear what proportion of the variance in bone density in elderly males is accounted for by testosterone status. We studied 112 ambulatory, elderly volunteers (mean age 71.7 years) and determined free testosterone (FT), as well as bone density measurements by photon absorptiometry at multiple sites. Our studies of 35 of these subjects 4 years later included morning FT and dual energy X-ray absorptiometry. There were no significant correlations between FT and bone density at multiple scanning sites with the effects of age partialed out. We suspect that our inability to detect a significant effect of FT on bone density was related to the relative strength of other determinants of bone density, as well as to the fact that FT values are far more dynamic than bone density.

Identification of the cellular protein encoded by the human Wilms' tumor (WT1) gene.

A putative tumor-suppressor gene (wt1) located at chromosome 11p13 and involved in Wilms' tumor development has recently been identified as a zinc finger polypeptide-encoding gene. The purpose of this study was to characterize the protein encoded by the human wt1 gene. The region spanning the entire zinc finger domain was amplified by polymerase chain reaction (PCR) and subcloned in the pATH 3 expression vector. Polyclonal antibodies against the fused TrpE-WT protein were raised. These antibodies immunoprecipitated a 49- to 51-kDa protein from hematopoietic tumor cells labeled in vivo with [35S]methionine. Subcellular fractionation and immunohistochemistry followed by confocal microscopy indicated that the Wilms' tumor gene product (WT1) is mainly localized within the nucleus.

Diagnosis and treatment of outpatient insomnia by psychiatric and nonpsychiatric physicians.

Insomnia is commonly encountered in general medical practice, but little is known about how primary care physicians manage this problem. We reviewed medical records describing 536 patient encounters in which either triazolam (Halcion) or flurazepam (Dalmane) was prescribed for outpatient use. Only 12% of the progress notes written by internists or surgeons contained even a remote reference to sleep, whereas 74% of psychiatrist's notes contained at least some sleep symptom documentation. In a multivariate analysis including the number of medical and psychiatric diagnoses, patient age, and physician gender, only the prescriber department was independently associated with the presence of symptom documentation. We also found that 30% of the prescriptions written by internists or surgeons were for inappropriately large quantities of these drugs (180 or more doses) compared with 6% of the prescriptions written by psychiatrists. We conclude that the evaluation of insomnia by nonpsychiatrists is often incomplete and that hypnotic drugs may be inappropriately prescribed by these physicians. Further efforts are needed to improve the management of insomnia by primary care physicians in the outpatient setting.

The effect of overlying calcification on lumbar bone densitometry.

We studied bone mineral density (BMD) of the spine using dual photon absorptiometry, as well as standard anterior-posterior and lateral lumbar spine X-ray film in 113 ambulatory elderly male volunteers with a mean age of 72 years (range 66-91 years). Each subject had three measurements taken for lumbar vertebrae 1 through 4: BMD, length of aortic calcification (AC), and degenerative facet sclerosis graded 0-3. A separate statistical model was fit to BMD for each vertebra using analysis of covariance. AC did not contribute significantly to BMD. BMD was increased by 0.28-0.03 g/cm2 (L1-L4) with a sclerosis score of 2, and by 0.47-0.25 g/cm2 with a sclerosis score of 3, P less than 0.001. The association between increased BMD and overlying facet sclerosis may be related to the bone density within the sclerosis itself or to an association between degenerative joint disease and a generalized increase in subchondral bone.

Lack of correlation between aortic calcification and bone density.

Previous radiographic studies have suggested a positive relationship between two degenerative processes associated with aging: calcification of the abdominal aorta and osteoporosis. Such a relationship has not been studied using modern quantitative densitometry. Aortic calcification was quantified on spinal radiographs from 112 elderly men. Bone mineral density was determined at six scanning sites using photon densitometry. There was no significant correlation between aortic calcification and bone mineral density at any of the scanning sites when the effect of age was held constant in the statistical analysis.

Distribution of the rDNA and three classes of highly repetitive DNA in the chromatin of interphase nuclei of Arabidopsis thaliana.

The distribution of the ribosomal RNA (rRNA) genes and three classes of highly repetitive DNA in the chromatin of interphase nuclei of Arabidopsis thaliana was studied for the first time through non-isotopic in situ hybridization and luminescence digital imaging microscopy. Each of the three classes of highly repetitive DNA exhibited a characteristic hybridization pattern, and one class was seen to be primarily localized on two chromocentres, which would allow it to distinguish a particular chromosome. The rDNA was consistently localized on the two largest chromocentres and on one or two smaller chromocentres. A limited number of nuclei exhibited more than four labelled chromocentres, indicative of either polypoidy or differential amplification of the rDNA. In nuclei where the nucleolus could be clearly observed, the nucleolar associated chromocentres (NACs) were seen to be labelled by the ribosomal DNA (rDNA) probe.

Failure to limit quantities of benzodiazepine hypnotic drugs for outpatients: placing the elderly at risk.

PURPOSE: The long-term use of benzodiazepine hypnotics by the elderly is associated with serious side effects, and prescriptions of large quantities of these agents allow such use. Therefore, we determined the quantities of these agents prescribed to outpatients in our Veterans Administration teaching hospital, and the relationship of patient age to total number of doses prescribed per prescription. PATIENTS AND METHODS: Pharmacy and patient records related to 655 consecutive prescriptions for triazolam (Halcion) and flurazepam (Dalmane) were reviewed. Only 266 (41%) of the prescriptions were for 30 or fewer doses, while 178 (27%) were written for 180 or more doses. RESULTS: Thirty-six percent of prescriptions for patients aged 65 years or older were for 180 or more doses, compared with 24% for those aged 45 to 64 years old, and 16% of the prescriptions for patients less than 45 years old (p less than 0.0001). In a multivariate analysis controlling for six other factors related to the total number of doses prescribed, patients aged 65 years or older were still more likely to receive a prescription for 180 or more doses (relative risk 1.9, 95% confidence interval 1.3, 2.8). CONCLUSION: We conclude that inappropriately large quantities of benzodiazepine hypnotics were commonly prescribed, and that patients aged 65 years or older were at greatest risk for receiving such prescriptions.

Influence of age and body weight on spine and femur bone mineral density in U.S. white men.

Bone mineral density (BMD) was measured in normal white males using 153 Gd dual-photon absorptiometry. Measurements were made on the lumbar spine (n = 315) and on the proximal femur (n = 282) utilizing three regions of interest. There was a small but significant age-related decrease in spinal BMD (r = -0.11; -0.001 g/cm2 per year) and trochanteric BMD (r = 0.27; -0.002 g/cm2 per year). The BMD of the other femoral sites decreased more rapidly; the femoral neck (r = -0.58; -0.005 g/cm2 per year) and Ward's triangle (r = -0.69; -0.007 g/cm2 per year) declined by about 21 and 34%, respectively, from age 20 to age 70. These femoral BMD decreases were three to four times greater than those usually seen in the peripheral skeleton in males but less than the decreases of 25-30 and 40% in the femoral neck and Ward's triangle of white females. This pattern of aging bone loss may partially explain the paucity of spine fractures and the lower incidence of hip fractures in males versus females.

Effects of patient age and physician training on choice and dose of benzodiazepine hypnotic drugs.

We conducted a cross-sectional review of all prescriptions (N = 554) for triazolam and flurazepam hydrochloride written by nonpsychiatrists to outpatients at a university affiliated Veterans Administration hospital. We sought to determine whether triazolam, an agent with a short half-life, was used preferentially in older patients (age greater than or equal to 70 years). We also wanted to determine whether dosages of triazolam or flurazepam were lowered in elderly patients. Our findings showed that prescriber level of training was a much stronger determinant of drug choice than patient age. Attending physicians prescribed flurazepam twice as often as interns. Lower dosages of both agents were prescribed more frequently to older patients. Our data suggest that some physicians choose a benzodiazepine hypnotic out of habit rather than application of pharmacologic principles, but reduce doses appropriately when prescribing to elderly patients.