Towards European automatic bioaerosol monitoring: Comparison of 9 automatic pollen observational instruments with classic Hirst-type traps

To benefit allergy patients and the medical practitioners, pollen information should be available in both a reliable and timely manner; the latter is only recently possible due to automatic monitoring. To evaluate the performance of all currently available automatic instruments, an international intercomparison campaign was jointly organised by the EUMETNET AutoPollen Programme and the ADOPT COST Action in Munich, Germany (March-July 2021). The automatic systems (hardware plus identification algorithms) were compared with manual Hirst-type traps. Measurements were aggregated into 3-hourly or daily values to allow comparison across all devices. We report results for total pollen as well as for Betula, Fraxinus, Poaceae, and Quercus, for all instruments that provided these data. The results for daily averages compared better with Hirst observations than the 3-hourly values. For total pollen, there was a considerable spread among systems, with some reaching R² > 0.6 (3 h) and R² > 0.75 (daily) compared with Hirst-type traps, whilst other systems were not suitable to sample total pollen efficiently (R² < 0.3). For individual pollen types, results similar to the Hirst were frequently shown by a small group of systems. For Betula, almost all systems performed well (R² > 0.75 for 9 systems for 3-hourly data). Results for Fraxinus and Quercus were not as good for most systems, while for Poaceae (with some exceptions), the performance was weakest. For all pollen types and for most measurement systems, false positive classifications were observed outside of the main pollen season. Different algorithms applied to the same device also showed different results, highlighting the importance of this aspect of the measurement system. Overall, given the 30 % error on daily concentrations that is currently accepted for Hirst-type traps, several automatic systems are currently capable of being used operationally to provide real-time observations at high temporal resolutions. They provide distinct advantages compared to the manual Hirst-type measurements.

O13: TUMOUR STROMAL CELLS - A CULPRIT IN BREAST CANCER RECURRENCE AFTER NEOADJUVANT CHEMOTHERAPY

Introduction

The goal of neoadjuvant chemothepaeutics(NACs) and surgical excision of breast cancer is to control and ultimately eliminate the malignant tumour. Despite advances in treatment, a subset of patients will develop disease recurrence. Tumour stromal cells(TSCs) are non-cancerous cells that support malignancy within the tumour microenvironment(TME). In particular, TSCs can suppress the host immune response to tumour. It is unclear if NACs affect the survival of–or alter the immunosuppressive functions of TSCs in breast cancer patients and if this correlates with recurrance or chemoresistance?

Method

TSCs and Tumour Associated Normal Stromal Cells(TANs) were isolated from tissue harvested from breast cancer patients at surgery. Clonogenic survival assays were performed following exposure to increasing doses of Paclitaxel (range 0-1000nM), Cyclophosphamide (range 0-3μM) and Doxorubicin (0-100nM). TSCs were co-cultured with CD4+ and CD8+ T-cells to determine the effect of chemotherapeutics on their ability to suppress T-cell proliferation.

Result

TSCs(n=5) are less susceptible to the cytotoxic effects of chemotherapy compared to TANs with 21%(p-0.0001), 21%(p-0.001) and 15%(p-0.026) more colonies across all doses of Paclitaxel, Cyclophosphamide and Doxorubicin respectively. Chemo naïve TSCs suppressed CD4+ and CD8+ T-Cell proliferation by 44% and 20.5% respectively(p-0.001, p-0.042). Interestingly, Paclitaxel-treated TSCs suppressed CD4+ proliferation by a further 11.1%(p-0.047) and CD8+ proliferation by 35.6%(p-0.017). Additionally, Cyclophosphamide-treated TSCs enhanced CD8+ suppression by 25.6%(p-0.029).

Conclusion

Our data indicate that NACs enhance the immunosuppressive function of TSCs - potentially creating an immune inert TME in vivo. Future studies will explore the correlation between NAC treatment, immunosuppressive activities within patient tumours/blood and recurrence.

Take-home message

After neoadjuvant chemotherapy, Tumour stromal cells are highly immunosuppressive and may contribute to breast cancer recurrence.

Containment of procedure-associated aerosols by an extractor tent: effect on nebulized drug particle dispersal

Background

Several medical procedures involving the respiratory tract are considered as ‘aerosol-generating procedures’. Aerosols from these procedures may be inhaled by bystanders, and there are consequent concerns regarding the transmission of infection or, specific to nebulized therapy, secondary drug exposure.

Aim

To assess the efficacy of a proprietary high-efficiency-particulate-air-filtering extractor tent on reducing the aerosol dispersal of nebulized bronchodilator drugs.

Methods

The study was conducted in an unoccupied outpatient room at St. James's Hospital, Dublin, Ireland. A novel real-time, fluorescent particle counter, the Wideband Integrated Bioaerosol Sensor (WIBS), monitored room air continuously for 3 h. Baseline airborne particle count and count during nebulization of bronchodilator drug solutions were recorded.

Findings

Nebulization within the tent prevented any increase over background level. Nebulization directly into room air resulted in mean fluorescent particle counts of 4.75 x 10⁵/m³ and 4.21 x 10⁵/m³ for Ventolin and Ipramol, respectively, representing more than 400-fold increases over mean background level. More than 99.3% of drug particles were <2 μm in diameter and therefore small enough to enter the lower respiratory tract.

Conclusion

The extractor tent was completely effective for the prevention of airborne spread of drug particles of respirable size from nebulized therapy. This suggests that extractor tents of this type would be efficacious for the prevention of airborne infection from aerosol-generating procedures during the COVID-19 pandemic.

Effectiveness of a plasma treatment device on microbial air quality in a hospital ward, monitored by culture

This study analysed the effectiveness of plasma treatment on airborne bacteria and surface counts during a 14-day intervention within a four-bedded bay in an adult respiratory ward at Cork University Hospital, Ireland. One-hundred-litre air samples were collected twice daily every weekday for 4 weeks, with settle plates and surface swabs. The plasma treatment did not have an effect on airborne bacteria and fungi that was detectable by culture. However, the possibility that culture-based sampling may be insufficiently sensitive to detect an effect, or that the duration of the study was insufficient for plasma treatment to affect a complex environment, cannot be excluded.

On-line monitoring of airborne bioaerosols released from a composting/green waste site

This study is the first to employ the on-line WIBS-4 (Wideband Integrated Bioaerosol Sensor) technique for the monitoring of bioaerosol emissions and non-fluorescing "dust" released from a composting/green waste site. The purpose of the research was to provide a "proof of principle" for using WIBS to monitor such a location continually over days and nights in order to construct comparative "bioaerosol site profiles". The real-time data obtained was then used to assess variations of the bioaerosol counts as a function of size, "shape", site location, working activity levels, time of day, relative humidity, wind speeds and wind directions. Three short campaigns were undertaken, one classified as a "light" workload period, another as a "heavy" workload period and finally a weekend when the site was closed. One main bioaerosol size regime was found to predominate: 0.5-3μm with morphologies ranging from elongated to ellipsoidal/spherical. The real-time number-concentration data provides a long-term "video" record of the site and were consistent with the Andersen sampling protocol performed that provides only a single "snapshot" for bioaerosol release. The number-concentration of fluorescent particles as a proportion of total particle counts amounted, on average, to ∼1% for the "light" workday period, ∼7% for the "heavy" workday period and ∼18% for the weekend. The bioaerosol release profiles at the weekend were considerably different from those monitored during the working weekdays.

Endovascular approaches to the ascending aorta for repair with straight and branched endografts: techniques and for what lesions

Traditionally ascending aortic lesions have been repaired in open fashion: stenotomy, cardiopulmonary bypass, with or without deep hypothermic circulatory arrest. However, a subsegment of patients are deemed too high risk for open intervention. In the advent of endovascular advancement, this subset of patients may be treated with the use of stents (physician made, off-label use), branched stents, through a variety of methods and approaches. Although there are currently no large randomized, prospective studies, success has been seen in smaller case series. This review article addresses the identification of anatomy amenable to endovascular repair for management of type A aortic dissection, pseudoaneurysm, and zone 0 lesions. Different approaches to repair, including transapical, transeptal, femoral, common carotid, and axillary graft insertion are also examined. For endovascular treatment of ascending aortic lesions to grow as a field, devices made specifically for the ascending aorta need to be designed and larger trials are necessary to evaluate the rates of complications, morbidity, and mortality, and graft patency.

Stent graft repair of paraanastomotic aneurysms after open descending thoracic and thoracoabdominal aortic aneurysm repair

BACKGROUND

After open thoracic and thoracoabdominal aortic aneurysm repair, anastomotic aneurysms can form at or near the suture lines of the graft. Endovascular repair is an alternative to complicated reoperative open surgery. We report on our experience with endovascular treatment of these lesions.

METHODS

A prospectively maintained database of endovascular thoracic aortic aneurysm repairs (TEVARs) performed at Mount Sinai Medical Center was reviewed and the initial procedures, comorbidities, clinical presentation, aneurysm characteristics, type of endograft, adjunctive procedures, and follow-up were analyzed.

RESULTS

Of the 135 TEVAR procedures performed between June 2001 and December 2008, 9 patients had anastomotic aneurysms after a previous open repair. The mean age was 66.7 (range 41-89) years, 67% of whom were male. Of these 9 patients, 5 had a descending thoracic repair, 3 had a type IV repair, and 1 had a type II thoracoabdominal repair. Aneurysm formation occurred in the following regions: proximal anastomosis (n = 2); intercostal patch (n = 1); distal anastomosis (n = 3); visceral patch (n = 2); and midgraft (n = 1). The initial technical success rate was 100%, with 8 patients receiving a thoracic tube graft and 1 a modular bifurcated device. Two patients required an adjunctive carotid-subclavian bypass and 2 required extraanatomic revascularization of the visceral arteries. Mean follow-up was 16.5 months. There was 1 perioperative death secondary to a postoperative myocardial infarction. Three patients developed an endoleak with 1 requiring an intervention. One patient required an open thoracoabdominal repair at 3 months for a penetrating ulcer at the visceral segment and another died from a ruptured thoracic aneurysm proximal to the stent graft at 72 months. Two more died during the follow-up period of non-aneurysm-related causes. Five patients had paraanastomotic shrinkage or no change and 1 had an increase in size, and 3 had no follow-up imaging.

CONCLUSIONS

Stent graft repair of paraanastomotic aneurysms after open descending thoracic and thoracoabdomninal repair is a reasonable option when patients have suitable anatomy. These patients, however, require close follow-up for the development of aneurysmal degeneration adjacent to the stent graft repair.

Single-incision laparoscopic-assisted right colon resection for cancer

The authors suggest that laparoscopic right colectomy utilizing a single port may be performed with excellent cosmetic results.

Introduction:

We present an approach to laparoscopic right colon resection utilizing a single port placed through the umbilicus. The technique described is performed through a single small umbilical incision with a virtually scar-free result.

Methods:

A 77-year-old woman with a tubulovillous adenoma in her cecum underwent a laparoscopic right colectomy using a single port placed through the umbilicus. Straight and reticulating laparoscopic instruments were utilized.

Results:

The total operative time was 112 minutes. No intraoperative or postoperative complications occurred. The patient was discharged home on day 5 postoperatively with normal bowel function and tolerance of a solid diet.

Conclusions:

Laparoscopic right colectomy can be safely performed through a single incision through the umbilicus with an excellent cosmetic result.

Is the length of follow-up evaluation in published reports on the treatment of infrainguinal occlusive disease decreasing?

BACKGROUND

There is increasing pressure for the rapid development and implementation of new techniques and procedures. This study examined whether or not there has been a trend toward increasingly short follow-up times for studies evaluating the treatment of lower-extremity occlusive disease.

METHODS

A search was performed of PubMed using the term "femoropopliteal occlusive disease" from 1976 to 2006. Reports describing the open and/or endovascular treatment of femoropopliteal occlusive disease were classified according to the number of patients, method of treatment, and follow-up time.

RESULTS

A total of 103 of the 435 reports met the inclusion criteria. Average follow-up times from 1976 to 1986 were a mean of 43.3 months and a median of 38.8 months, from 1986 to 1996 were a mean of 32.4 months and a median of 16.9 months, from 1996 to 2006 were a mean of 22.6 months and a median of 16.5 months.

CONCLUSIONS

The number of reports on femoropopliteal occlusive disease treatment has increased. The length of follow-up period was 2- to 3-fold longer for reports on open procedures compared with those on endovascular procedures. Whether length of follow-up evaluation and reporting intervals should be standardized warrants further investigation.

Single-incision laparoscopic appendectomy: an early experience

Acute appendicitis is one of the most common causes of abdominal pain that a general surgeon will encounter. We describe our modification to the laparoscopic appendectomy: a single-incision laparoscopic (SILS) appendectomy completed entirely intracorporeally. From September 2008 to September 2009, a retrospective review of the electronic medical record was performed in all patients who underwent a SILS appendectomy to specifically analyze the demographic characteristics, time in the operating room to perform SILS appendectomy, length of postoperative hospital stay, and postoperative complications. Twenty-five patients underwent SILS appendectomy in the study period. There were 18 males and seven females with a mean age of 41 ± 15 years and mean body mass index of 26.5 ± 5 kg/m². Single-incision laparoscopic appendectomy was performed successfully in all of our cases (100%). Mean operative time was 56 ± 16 minutes. Blood loss in all cases was minimal and there were no intraoperative complications. We successfully completed 25 appendectomies using the SILS method. Operative times were similar compared with the traditional laparoscopic technique. We believe that the SILS appendectomy is a safe and effective method that leaves a virtually invisible scar.

Proportion of patients with critical limb ischemia who require an open surgical procedure in a center favoring endovascular treatment

Endovascular interventions have gained widespread acceptance as primary and secondary treatments for critical lower extremity ischemia (CLI), and many believe there is little need for open bypasses for CLI. Despite this, some patients presenting with CLI require traditional lower extremity bypass procedures at some point for successful limb salvage. To determine the proportion of patients requiring an open procedure, we reviewed our 1-year experience with CLI patients at a center committed to endovascular approaches whenever possible. We reviewed all patients presenting with CLI from January 1, 2007 to December 31, 2007. CLI was defined as ischemic rest pain, nonhealing ulceration, or gangrene for which a major amputation was imminently required. All patients underwent duplex and conventional angiography before intervention. Endovascular treatments were favored as primary, secondary, or tertiary treatments, if possible. If these failed or were impossible, standard lower extremity bypasses were performed. One hundred and forty-eight patients presented with primary, secondary, or tertiary CLI over this 1-year period. Of these, 63 (42%) were treated successfully with an endovascular intervention, and 69 (47%) required standard lower extremity bypass, and 16 (11%) required a combined endovascular and open procedure (i.e., hybrid procedure). Of these 148 patients, 46 (31%) were presenting with secondary, tertiary, or more CLI after failed previous (1-5) procedures. Despite the initial enthusiasm that the majority of patients presenting with CLI may be treated with endovascular procedures, there exists a significant cohort of patients that will ultimately require standard open surgical procedures.

Proportion of Patients with Critical Limb Ischemia who Require an Open Surgical Procedure in a Center Favoring Endovascular Treatment

Endovascular interventions have gained widespread acceptance as primary and secondary treatments for critical lower extremity ischemia (CLI), and many believe there is little need for open bypasses for CLI. Despite this, some patients presenting with CLI require traditional lower extremity bypass procedures at some point for successful limb salvage. To determine the proportion of patients requiring an open procedure, we reviewed our 1-year experience with CLI patients at a center committed to endovascular approaches whenever possible. We reviewed all patients presenting with CLI from January 1, 2007 to December 31, 2007. CLI was defined as ischemic rest pain, nonhealing ulceration, or gangrene for which a major amputation was imminently required. All patients underwent duplex and conventional angiography before intervention. Endovascular treatments were favored as primary, secondary, or tertiary treatments, if possible. If these failed or were impossible, standard lower extremity bypasses were performed. One hundred and forty-eight patients presented with primary, secondary, or tertiary CLI over this 1-year period. Of these, 63 (42%) were treated successfully with an endovascular intervention, and 69 (47%) required standard lower extremity bypass, and 16 (11%) required a combined endovascular and open procedure (i.e., hybrid procedure). Of these 148 patients, 46 (31%) were presenting with secondary, tertiary, or more CLI after failed previous (1-5) procedures. Despite the initial enthusiasm that the majority of patients presenting with CLI may be treated with endovascular procedures, there exists a significant cohort of patients that will ultimately require standard open surgical procedures.

The biological response of MCF7 breast cancer cells to proteosome inhibition or gamma-radiation is unrelated to the level of p53 induction

The p53 tumour suppressor is stabilised following exposure to genotoxic agents, such as gamma-radiation. Cell responses to p53 stabilisation include induction of apoptosis and/or cell cycle arrest. Several studies have suggested that gamma-radiation stabilises p53 by blocking ubiquitin mediated proteolysis. Here we have compared the biological activities of p53 stabilized following exposure to gamma-radiation or treatment with the proteosome inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (ALLN) in MCF7 cells with wild type p53. Stabilisation of p53 by ALLN was reversible and was not blocked by caffeine. Although ALLN was a more effective p53 stabilising agent than gamma-radiation, ALLN was not as effective at inducing cell cycle arrest/apoptosis as gamma-radiation. Although p53 stabilised by ALLN and gamma-radiation were both able to bind DNA and activate transcription, ALLN did not increase expression of BAX, which is involved in p53-induced apoptosis. Therefore, p53 stabilised by different agents is not always biologically active to the same extent and additional alterations triggered by gamma-radiation may enable p53 to activate a subset of critical target genes, such as BAX, which are required for p53 responses.

ASPP proteins specifically stimulate the apoptotic function of p53

We identified a family of proteins termed ASPP. ASPP1 is a protein homologous to 53BP2, the C-terminal half of ASPP2. ASPP proteins interact with p53 and specifically enhance p53-induced apoptosis but not cell cycle arrest. Inhibition of endogenous ASPP function suppresses the apoptotic function of endogenous p53 in response to apoptotic stimuli. ASPP enhance the DNA binding and transactivation function of p53 on the promoters of proapoptotic genes in vivo. Two tumor-derived p53 mutants with reduced apoptotic function were defective in cooperating with ASPP in apoptosis induction. The expression of ASPP is frequently downregulated in human breast carcinomas expressing wild-type p53 but not mutant p53. Therefore, ASPP regulate the tumor suppression function of p53 in vivo.

Randomized, controlled study of low-dose 5-fluorouracil in primary trabeculectomy

PURPOSE

To report a randomized clinical trial of postoperative subconjunctival injections of low-dose 5-fluorouracil in patients undergoing primary trabeculectomy.

METHODS

In a prospective, randomized clinical trial, 40 eyes of 40 patients were randomized to the low-dose 5-fluorouracil group and received three subconjunctival injections of 5 mg each over 11 postoperative days, and 40 eyes of 40 patients were randomized to trabeculectomy without 5-fluorouracil.

RESULTS

Mean (+/-SD) preoperative and 1-year postoperative intraocular pressures in the 5-fluorouracil group were 26.9 (+/-9.5) and 15.3 (+/-5.8) mm Hg, respectively. In the control group these were 25.9 (+/-8.1) mm Hg, and 15.8 (+/-5.1) mm Hg, respectively. The patients who received 5-fluorouracil had a mean reduction in intraocular pressure of 11.5 (+/-9.1) mm Hg at a median follow-up of 52.3 weeks. The control group had a mean reduction in intraocular pressure of 10.2 (+/-8.7) mm Hg at a median follow-up of 52.6 weeks. These differences were not statistically significant.

CONCLUSIONS

Three postoperative subconjunctival 5-fluorouracil injections of 5 mg each after trabeculectomy in eyes at low risk for failure had no statistically or clinically significant effect on reduction of intraocular pressure with 1-year follow-up. Enhancement of success in this group of patients may require a larger total dose of 5-fluorouracil.

Proapoptotic p53-interacting protein 53BP2 is induced by UV irradiation but suppressed by p53

p53 is an important mediator of the cellular stress response with roles in cell cycle control, DNA repair, and apoptosis. 53BP2, a p53-interacting protein, enhances p53 transactivation, impedes cell cycle progression, and promotes apoptosis through unknown mechanisms. We now demonstrate that endogenous 53BP2 levels increase following UV irradiation induced DNA damage in a p53-independent manner. In contrast, we found that the presence of a wild-type (but not mutant) p53 gene suppressed 53BP2 steady-state levels in cell lines with defined p53 genotypes. Likewise, expression of a tetracycline-regulated wild-type p53 cDNA in p53-null fibroblasts caused a reduction in 53BP2 protein levels. However, 53BP2 levels were not reduced if the tetracycline-regulated p53 cDNA was expressed after UV damage in these cells. This suggests that UV damage activates cellular factors that can relieve the p53-mediated suppression of 53BP2 protein. To address the physiologic significance of 53BP2 induction, we utilized stable cell lines with a ponasterone A-regulated 53BP2 cDNA. Conditional expression of 53BP2 cDNA lowered the apoptotic threshold and decreased clonogenic survival following UV irradiation. Conversely, attenuation of endogenous 53BP2 induction with an antisense oligonucleotide resulted in enhanced clonogenic survival following UV irradiation. These results demonstrate that 53BP2 is a DNA damage-inducible protein that promotes DNA damage-induced apoptosis. Furthermore, 53BP2 expression is highly regulated and involves both p53-dependent and p53-independent mechanisms. Our data provide new insight into 53BP2 function and open new avenues for investigation into the cellular response to genotoxic stress.

Stress signals induce transcriptionally inactive E2F-1 independently of p53 and Rb

One of the common features of cellular response to stress is cell cycle arrest or apoptosis. E2F is one of the key factors which controls cell cycle progression. Overexpression of E2F-1 can also induce apoptosis. In order to understand the role of E2F-1 in cellular response to stress, we studied the E2F-1 response in various cell lines to different types of stress signals including UV irradiation, cisplatin, etoposide and hypoxia. We showed here that the expression level of E2F-1 can be up regulated by the treatment of DNA damage agents as well as hypoxia. The kinetics of E2F-1 increase was dependent on the types of inducer and was similar to that of p53. However, stress signals can induce E2F-1 expression independently of p53 and Rb. Furthermore, the induced E2F-1 was transcriptionally inactive. All these results suggested that E2F-1 may play a very important role in cellular response to stress and this novel role of E2F-1 is independent of its transactivation function.

Continuing the search for WBGT clothing adjustment factors

The original concept for the heat stress limits adopted by the American Conference of Governmental Industrial Hygienists (ACGIH) was that the threshold for heat stress can be marked by environmental conditions (WBGT) that are adjusted for metabolic rate. The underlying data were based on ordinary work clothes. The Physical Agents Committee promoted clothing adjustment factors within the industrial hygiene community through a revision in the TLVs for heat stress in 1990. As approved, there were adjustment factors for three other clothing ensembles. To extend and further understand adjustment factors, adjustments for commercially available clothing ensembles and prototype ensembles have been examined. The fundamental principle of the assignment of an adjustment factor to an ensemble begins with establishing critical environmental conditions in which test subjects were just able to maintain thermal equilibrium. Four or five subjects for each ensemble walked on a tread-mill inside a climatic chamber under controlled conditions of heat stress. During each test, heart rate and core temperature were continuously monitored. After a physiological steady-state was achieved, temperature and humidity were slowly increased to maintain relative humidity at 20 percent, 50 percent, or 70 percent. Metabolic rate was assessed by measuring the rate of oxygen consumption. Reviewing a trial, the critical conditions were noted as the time when thermal regulatory control was lost (called the inflection point and marked by a steady increase in core temperature). The climatic conditions at the inflection point were used to assign a critical WBGT. A WBGT representative of each ensemble was assigned through a weighted average of different protocols. Clothing adjustment factors representing an equivalent increase in WBGT were computed by noting the difference between the representative WBGT of the cotton work clothes and the other clothing ensembles. The results suggested adjustment factors with reference to ordinary work clothes from the least stress at -2.1 to 5.5 degrees C-WBGT. The adjustment factors were reasonably well predicted by a linear regression based on a computed value for total evaporative resistance (r2 = 0.92).

RB regulates the stability and the apoptotic function of p53 via MDM2

The binding of RB to MDM2 is shown to be essential for RB to overcome both the antiapoptotic function of MDM2 and the MDM2-dependent degradation of p53. The RB-MDM2 interaction does not prevent MDM2 from inhibiting p53-dependent transcription, but the RB-MDM2 complex still binds to p53. Since RB specifically rescues the apoptotic function but not the transcriptional activity of p53 from negative regulation by MDM2, transactivation by wild-type p53 is not required for the apoptotic function of p53. However, an RB-MDM2-p53 trimeric complex is active in p53-mediated transrepression. These data link directly the function of two tumor suppressor proteins and demonstrate a novel role of RB in regulating the apoptotic function of p53.

Physical and functional interactions between p53 and cell cycle co-operating transcription factors, E2F1 and DP1

One way in which wild-type p53 is able to regulate cell cycle progression is thought to be via the induction of its downstream target gene Waf1/CIP1, thus indirectly regulating the transcriptional activity of E2F. The E2F transcription factors are known to be key effectors of the cell cycle. We report here that there is a physical and functional interaction between p53 and two of the components of the E2F transcription factors, E2F1 and DP1. The expression of wild-type p53 can inhibit the transcriptional activity of E2F, and the expression of both E2F1 and DP1 can also downregulate p53-dependent transcription. The transcriptional activity of p53 is known to be inhibited by the direct binding of mdm2, but we demonstrate here that both E2F1 and DP1 can inhibit p53 transcriptional activity independently of mdm2. Detailed studies of protein-protein interactions have provided evidence that E2F1 and its co-operating factor DP1 can complex with p53 both in vitro and in vivo.

Comparisons of methods to detect glaucomatous optic nerve damage

PURPOSE

Various techniques of optic disc and nerve fiber layer evaluation may be used to detect structural glaucomatous damage. The authors compared several qualitative and quantitative methods to determine their relative sensitivities and specificities to detect the presence of glaucomatous visual field loss.

METHODS

Fifty-one healthy eyes, 169 ocular hypertensive eyes with normal visual fields, and 132 glaucomatous eyes with early visual field defects were evaluated with qualitative and quantitative measures of structural damage to the optic nerve and nerve fiber layer. Qualitative evaluations were performed by three experienced masked observers who independently graded stereoscopic color disc and monochromatic nerve fiber layer photographs. Quantitative measurements of disc rim area and nerve fiber layer height were made with digitized image analysis of videographic images. Manual planimetric measurements of disc rim area were made from enlarged prints of stereoscopic optic disc photographs. Diagnostic precision was defined as the total proportion of correct diagnoses for the presence or absence of visual field loss.

RESULTS

The diagnostic precision of results of a quantitative disc examination (81%) was greater than those of a qualitative nerve fiber layer examination (75%). Quantitative nerve fiber height measurement had the highest sensitivity rate (73%) and results of the qualitative disc examination had the highest specificity rate (87%) of the methods tested.

CONCLUSION

The diagnostic precision of disc evaluation was superior to other methods, including nerve fiber layer examination, in correctly determining the presence of structural glaucomatous damage at the early visual field loss stage.

A surgical method to repair leaking filtering blebs

Surgical revision of a chronically-thinned filtering bleb with a leak at the limbus is described. After surgical excision of the scarred cystic conjunctiva and Tenon's fascia surrounding the leaking bleb, relatively uninvolved conjunctiva and Tenon's fascia are mobilized with the help of a large relaxing incision in the superior fornix and sutured over the area of filtration. We have used this technique successfully in five cases to provide fresh tissue to repair the bleb leak and restore adequate filtration.

"Idiopathic" deep venous thrombosis: the value of routine abdominal and pelvic computed tomographic scanning

Recent studies have demonstrated an increased incidence in the diagnosis of malignancy subsequent to the diagnosis of deep venous thrombosis or pulmonary embolus. We reviewed 237 patients with venographically proven deep venous thrombosis over eight years. Of these, 216 had at least one predisposing cause for deep venous thrombosis; of the remaining 21 patients, three had hemoglobin determinations revealing anemia and were subsequently shown to have a malignant disease. One patient had two chief complaints and was shown to have deep venous thrombosis and malignant disease. The 17 remaining patients underwent computed tomographic scan of the abdomen and seven (41%) had abnormalities which proved to be malignant in origin. One further patient was diagnosed with carcinoma of the cervix two months following the onset of deep venous thrombosis. The remaining 10 patients continued free of malignant disease. Five have died of circulatory causes in the follow-up period. Seven of the nine patients diagnosed with malignancy succumbed within six months of the diagnosis. We conclude that only a small group of patients with deep venous thrombosis will have no identifiable cause for deep venous thrombosis and be asymptomatic for malignancy. Complete blood count, physical examination and computed tomographic scan of the abdomen at the time of venographic diagnosis of deep venous thrombosis is useful in diagnosis of "occult" malignancy. The number of gynecologic tumors would suggest the need for pelvic examination as well as radiographic examination. The presence of deep venous thrombosis and malignant disease is an ominous prognostic sign.

The Study of Surfaces Using Ion Beams

The study of surfaces has progressed by the development of techniques which use different probing species in the form of electrons, ions and photons. Specialisation within the use of each probe has resulted in the subsequent development of methods of analysis tuned to obtain specific information about a surface. In this presentation the various uses of ion scattering spectrometry over a wide range of energies will be reviewed to illustrate how it has been successfully used to yield structural and compositional information of the surface atomic layer and the near surface region.