The Impact of COVID-19 on Emergent Large-Vessel Occlusion: Delayed Presentation Confirmed by ASPECTS

BACKGROUND AND PURPOSE

Our hypothesis is that the COVID-19 pandemic led to delayed presentations for patients with acute ischemic stroke. This study evaluates the impact of the coronavirus disease 2019 pandemic on presentation, treatment, and outcomes of patients with emergent large-vessel occlusion using data from a large health system in the Bronx, New York.

MATERIALS AND METHODS

We performed a retrospective cohort study of 2 cohorts of consecutive patients with emergent large-vessel occlusion admitted to 3 Montefiore Health System hospitals in the Bronx from January 1 to February 17, 2020, (prepandemic) and March 1 to April 17, 2020 (pandemic). We abstracted data from the electronic health records on presenting biomarker profiles, admission and postprocedural NIHSS scores, time of symptom onset, time of hospital presentation, time of start of the thrombectomy procedure, time of revascularization, presenting ASPECTS, TICI recanalization score, mRS, functional outcomes, and mortality.

RESULTS

Of 179 patients admitted with ischemic stroke during the study periods, 80 had emergent large-vessel occlusion, of whom 36 were in the pandemic group. Patients in the pandemic group were younger (66 versus 72 years, P < .061) and had lower ASPECTS (7 versus 9, P < .001) and took longer to arrive at the hospital (361  versus 152 minutes, P < .004) with no other major differences. There was a decreased rate of thrombolysis administration (22% versus 43%, P < .049) and a decreased number of patients treated with mechanical thrombectomy (33% versus 61%, P < .013).

CONCLUSIONS

The pandemic led to delays in patients arriving at hospitals, leading to decreased patients eligible for treatment, while in-hospital evaluation and treatment times remain unchanged.

COVID-19-Associated Carotid Atherothrombosis and Stroke

We present a radiology-pathology case series of 3 patients with coronavirus disease 2019 (COVID-19) with acute ischemic stroke due to fulminant carotid thrombosis overlying mild atherosclerotic plaque and propose a novel stroke mechanism: COVID-associated carotid atherothrombosis.

Diagnostic Utility of Optic Nerve Measurements with MRI in Patients with Optic Nerve Atrophy

BACKGROUND AND PURPOSE

No MR imaging measurement criteria are available for the diagnosis of optic nerve atrophy. We determined a threshold optic nerve area on MR imaging that predicts a clinical diagnosis of optic nerve atrophy and assessed the relationship between optic nerve area and retinal nerve fiber layer thickness measured by optical coherence tomography, an ancillary test used to evaluate optic nerve disorders.

MATERIALS AND METHODS

We evaluated 26 patients with suspected optic nerve atrophy (8 with unilateral, 13 with bilateral and 5 with suspected but not demonstrable optic nerve atrophy) who had both orbital MR imaging and optical coherence tomography examinations. Forty-five patients without optic nerve atrophy served as controls. Coronal inversion recovery images were used to measure optic nerve area on MR imaging. Retinal nerve fiber layer thickness was determined by optical coherence tomography. Individual eyes were treated separately; however, bootstrapping was used to account for clustering when appropriate. Correlation coefficients were used to evaluate relationships; receiver operating characteristic curves, to investigate predictive accuracy.

RESULTS

There was a significant difference in optic nerve area between patients' affected eyes with optic nerve atrophy (mean, 3.09 ± 1.09 mm²), patients' unaffected eyes (mean, 5.27 ± 1.39 mm²; P = .008), and control eyes (mean, 6.27 ± 2.64 mm²; P < .001). Optic nerve area ≤ 4.0 mm² had a sensitivity of 0.85 and a specificity of 0.83 in predicting the diagnosis of optic nerve atrophy. A significant relationship was found between optic nerve area and retinal nerve fiber layer thickness (r = 0.68, P < .001).

CONCLUSIONS

MR imaging-measured optic nerve area ≤ 4.0 mm² has moderately high sensitivity and specificity for predicting optic nerve atrophy, making it a potential diagnostic tool for radiologists.

Subspecialized radiology review at multidisciplinary pancreas conference: impact on patient management

PURPOSE

At our tertiary medical center, multidisciplinary subspecialists meet twice a week during a CME-accredited conference to discuss oncologic and non-oncologic patients with pancreatic diseases at which time a subspecialized abdominal staff radiologist reinterprets the patient's relevant imaging studies. This study assesses the changes in patient management due to imaging reinterpretation during multidisciplinary pancreas conference (MPC).

MATERIALS AND METHODS

In this retrospective, IRB-approved, HIPAA-compliant study, imaging studies of all patients discussed at MPC between July 1 and December 31, 2015 were assessed for technical adequacy, and original reports analyzed for congruency with reinterpretation. Management measures included change in diagnosis, clinical stage, treatment, or workup. Additional data were obtained on referring services affected and their resultant change in practice. Changes in surgical resectability, surgical approach, or delayed operative dates were noted for surgeons. Changes in chemotherapeutic or radiation oncology regimens as well as decisions for additional imaging, laboratory workup, or histologic evaluation were also recorded.

RESULTS

A total of 252 patients were included (54.4% males, 45.6% females, mean age 63.71 years). Relevant imaging consisted of 142 abdominal CT scans, 112 abdominal MRI scans, 1 abdominal ultrasound, and 1 nuclear medicine octreotide study of which 69.4% were performed in-house. Image quality was deemed appropriate in 95.2%. Cases presented included solid pancreatic malignancies (n = 140; 55.6%), cystic pancreatic lesions (n = 41; 16.3%), acute and chronic inflammatory conditions (n = 52; 20.6%), and miscellaneous entities (n = 10; 4.0%); 9 (3.6%) cases were normal. Image reinterpretation was congruent with original reports in 56.7%, with minor, moderate, and major discrepancies occurring in 9.5, 26.2%, and 7.5% of cases, respectively. Incongruent reinterpretation was predominantly due to perceptional errors (false-negative reports due to missed findings) and interpretative errors (false-positive results due to over-reporting or misclassification of diagnoses). Services most commonly affected included surgical oncology, radiology, and gastroenterology at 16.7%, 13.1%, and 12.7% of cases, respectively. Management changes included a change in diagnosis in 8.7%, change in clinical stage in 8.7%, change in treatment in 17.9%, and further workup needed in 19.0% of patients, respectively. No change in management occurred in the remaining 61.5% of cases.

CONCLUSIONS

Subspecialized abdominal radiologist reinterpretation in the context of more comprehensive patient information heavily impacts the multidisciplinary management of patients with pancreatic disorders. Further efforts are needed to solidify the abdominal radiologist's role in the multidisciplinary clinical setting.

Developing a national colorectal educational agenda: a survey of the Association of Coloproctology of Great Britain and Ireland

AIM

In order to develop its education agenda, the Association of Coloproctology of Great Britain and Ireland (ACPGBI) sought the opinion of its members on current coloproctology training needs. The aims of this study were to canvass multidisciplinary needs and explore the perceived gaps and barriers to meeting them.

METHOD

A learner-needs analysis was performed between July 2015 and October 2016. A bespoke electronic survey was sent to 1453 colorectal healthcare professionals [ACPGBI membership (1173), colorectal nurse specialists and allied health professionals (NAHPs) (261) and regional chapter-leads (19)] seeking their needs, experiences and barriers to training across the coloproctology disciplines.

RESULTS

In all, 390 responses were received [26.8% overall; 180 consultants/trainees (15%); 196 NAHPs (75%); 14 (74%) chapter-leads]. Lack of funding and difficulties in obtaining study leave were the most frequently reported barriers to course and conference attendance. Transanal total mesorectal excision and laparoscopic training were the top educational needs for consultants and trainees respectively. 79% of NAHP respondents reported education gaps on a broad range of clinical and non-clinical topics. NAHPs lacked information on relevant training opportunities and 27% felt available courses were insufficient to meet their educational needs. Wide heterogeneity in ACPGBI chapter composition and activity was reported. All groups felt the ACPGBI should increase the number of courses offered with coloproctology knowledge updates commonly requested.

CONCLUSION

A series of training needs across the coloproctology disciplines have been identified. These will underpin the development of the educational agenda for the ACPGBI.

Prevalence of infraocclusion of primary molars determined using a new 2D image analysis methodology

BACKGROUND

The reported prevalence of infraocclusion varies widely, reflecting differences in definitions and measurement/scoring approaches. This study aimed to quantify the prevalence and extent of infraocclusion in singletons and twins during the late mixed dentition stage of dental development using a new diagnostic imaging method and objective criteria. The study also aimed to determine any associations between infraocclusion and gender, arch type, arch side and tooth type.

METHODS

Two samples were analysed, 1454 panoramic radiographs of singletons and 270 dental models of twins. Both samples ranged in age from 8 to 11 years. Adobe Photoshop CS5 was used to measure the extent of infraocclusion. Repeatability tests showed systematic and random errors were small.

RESULTS

The prevalence in the maxilla was low (<1%), whereas the prevalence in the mandible was 22% in the singleton sample and 32% in the twin sample. The primary mandibular first molar was affected more often than the second molar. There was no significant difference in the expression between genders or sides.

CONCLUSIONS

A new technique for measuring infraocclusion has been developed with high intra- and interoperator reproducibility. This method should enhance early diagnosis of tooth developmental abnormalities and treatment planning during the late mixed dentition stage of development.

Abstract P5-17-04: Breast conserving surgery alone for ductal carcinoma in situ: Factors associated with increased risk of local recurrence

Background: There is ongoing debate regarding the added benefit of radiation therapy (RT) for patients with ductal carcinoma in situ (DCIS) believed to be at low risk for recurrence after wide local excision (WLE) alone since RT is costly and can cause significant adverse effects. In this retrospective study we aimed to identify clinicopathological characteristics associated with an increased risk for ipsilateral local recurrence (LR) in patients not undergoing RT.

Methods: All patients with DCIS treated with WLE alone at the Beth Israel Deaconess Medical Center, Boston between 2000 and 2010 were identified. We collected data on demographics, parity, personal or family history of breast cancer, exogenous hormone use, tobacco use, comorbidities, genetic mutation carrier status, imaging interval, and tumor-specific characteristics (size, margins, grade, architectural subtype, presence of necrosis, estrogen receptor status). We analyzed their effects on the risk of LR.

Results: The study cohort included 281 eligible patients (mean age at diagnosis 59 years, range 33-90). Median follow-up time was 8 years (range 0.11-16.59 years); 59 patients were excluded because they were not followed in our institution after undergoing WLE. LR occurred in 19 of 222 patients (9%), with a recurrence rate of 11.3 per 1000 person-years. The median time from excision to LR was 4.2 years (range, 0.8-11.7). The risk of recurrence was lower for the 64 patients with nuclear grade (NG) I tumors than for the 110 patients with a NG II or 20 patients NG III tumors (3%, 9%, and 20%, respectively, p for trend = 0.01). The mean margin width was 1.8 mm in patients experiencing LR, versus 2.5 mm in patients without LR (p=0.4). Patients who had used hormone replacement therapy or oral contraceptives (n=61) or patients with a history of tobacco use (n=41) had higher rates of LR than those who did not, although these did not reach statistical significance (15% versus 6%, p=0.06; and 17% versus 7%, p=0.07 respectively). There was no significant correlation between the use of tamoxifen or aromatase inhibitors and the risk of LR.

Conclusions: Our data indicate that higher nuclear grade, narrower margin width, use of exogenous hormones, and smoking history may be associated with an increased risk of LR. The evaluation of these factors may be helpful when considering whether to use adjuvant RT or not for patients with DCIS.

Citation Format: Recht A, Mele A, Mehta P, Brook A, Slanetz P, Sharma R. Breast conserving surgery alone for ductal carcinoma in situ: Factors associated with increased risk of local recurrence. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-17-04.

Lateral decubitus positioning for cervical nerve root block using CT image guidance minimizes effective radiation dose and procedural time

BACKGROUND AND PURPOSE

Cervical steroid injections are a minimally invasive means of providing pain relief to patients with cervical radiculopathy. CT guidance offers many potential advantages. We developed a technique with the patient in the lateral position with a lateral needle trajectory to minimize the required needle depth from skin to target and a near-vertical needle trajectory. The aim of this study was to analyze the cohort for complications, procedural time, and effective radiation dose.

MATERIALS AND METHODS

This was a retrospective evaluation of a single-center patient cohort. PACS images from the procedures were reviewed for needle depth, procedural time, and CTDI(vol). An anatomically relevant conversion factor was used to calculate the effective dose.

RESULTS

One hundred sixteen cases from 110 patients were identified. The average patient age was 55 years. There were no complications. In 50% of cases, C5-6 was targeted. The average time was 6 minutes, and the average effective radiation dose, 0.51 mSv (0.21-2.56 mSv). Needle-insertion length from the skin to the target was highly correlated with a need for >3 needle repositioning adjustments and scan series (ρ = 0.52, P < .001) and increased procedural time (ρ = 0.42, P < .001). The angle of needle insertion relative to the floor was significantly correlated with an increased number of needle adjustments for depths >25 mm and a longer procedural time (ρ = 0.29, P = .01) but not for depths <25 mm.

CONCLUSIONS

The lateral patient position with CT guidance is safe and allows use of a short needle in a vertical trajectory. This reduces the number of needle adjustments and imaging series to provide a short procedural time with a low effective radiation dose from the procedure.

Safety of 1000 CT-guided steroid injections with air used to localize the epidural space

Historically, ESIs were performed without any imaging guidance, resulting in erroneous placement in up to 30% of injections. Fluoroscopic imaging is now used to guide most procedures. Recently, several reports have described the use of CT to guide ESIs instead of fluoroscopy. CT provides the ability to use air as contrast to localize the epidural space. This retrospective review will discuss findings in 1000 CT-guided ESIs with air localization.

The effect of a Radiology Conference consultation on cancer patients management

BACKGROUND

The quantitative effect of consultation on cancer patient's management at a Radiology Conference was studied.

PATIENTS AND METHODS

This prospective study included consecutive patients presented at the Radiology Conference of the Division of Oncology. Following the case presentation and discussion, the patient's oncologist completed a questionnaire which asked whether the consultation at the conference added new information regarding the patient's disease status, whether it influenced patient management and, if so, to what extent.

RESULTS

Three hundred and eighty-three patients were included in the study. Significant new information was added for 189 (49%) patients and less consequential information was added for 134 (35%) patients. Major changes in management occurred in 143 (37%) patients after the Radiology Conference and minor changes were made in 56 (15%) patients. The influence of the cancer type on the rate of significant change in treatment and on the rate of major information addition was not statistically significant.

CONCLUSION

Consultation at a Radiological Conference in a tertiary center led to major changes in the management of 37% of the cancer patients presented and provided important information regarding the patient's disease in up to 50% of patients.

A framework for assessing regional biodiversity condition under changing environments of the arid Australian rangelands

Rangelands support many ecosystem services important to humans, including climate regulation. They also have a significant role to play in the mitigation of greenhouse gases. However, the capacity of any rangeland to do this depends foremost upon the condition of biodiversity, and the functioning of its ecosystems. Considerable research has been undertaken on rangeland condition but it has not yet included the assessment of biodiversity (plants, animals and microbes) as a primary focus. Rangeland managers have struggled to assess biodiversity condition because it is rarely defined, is everywhere (so what do you assess?), is always changing in response to natural and human disturbances (so how do you know when it has changed?) and what amount signals management action. Here we present a framework that addresses these issues, and apply it to select surrogates and indicators that are scientifically defensible in biological and planning terms for assessing biodiversity. An arid Australian rangeland region is used as a case study to develop and apply our approach. We were not able to illustrate interpretation of condition because of the absence of long-term monitoring data in Australian rangelands, but we do provide guiding principles about sampling design and analytical methods for interpretation that use raw data rather than multimetrics. We discovered that different management outcomes expected to be informed from assessing biodiversity condition affected surrogate and indicator choice, and that a number indicators were not robust when assessed on conceptual relevance, measurement qualities, feasibility of implementation and policy and management relevance for four different management outcomes. Our work highlights the importance of stating the expected outcomes of biodiversity condition assessments up front, so that indicators relevant to future management are chosen. It also shows that critical thought on the robustness of indicators is warranted, especially as condition assessments under climate change will require information on the functional traits of species. We conclude by assessing the strengths and weaknesses of our framework in relation to environmental planning.

A role for Ebi in neuronal cell cycle control

Mutations in ebi were isolated as enhancers of an over-proliferation phenotype generated by elevated E2F/DP activity in the Drosophila eye. ebi alleles also strongly suppress a phenotype caused by the cyclin-dependent kinase inhibitor p21, restoring S phases in the second mitotic wave of the developing eye disk. ebi mutant embryos display ectopic S phases within the peripheral nervous system and central nervous system at a time in development when neuronal precursor cells would normally begin to differentiate. Consistent with this, we find that ebi mutants have a reduced capacity to undergo neuronal differentiation, that Ebi physically interacts with Sina and phyllopod, and that Ebi promotes Ttk88 degradation in vitro and in S2 cells. Ectopic expression of Ttk88 inhibited differentiation in embryos and eye discs; however, this block to differentiation was insufficient to promote S phase entry in either of the situations where ebi mutations gave this effect. We conclude that Ebi has two distinct functions; it promotes the degradation of a repressor of neuronal differentiation (Ttk88), and has a second independent function that limits S phase entry.

Benign parotid hypertrophy on +HIV patients: limited late failures after external radiation

PURPOSE

Although 8-10 Gy of external radiation therapy for +HIV associated parotid hypertrophy has achieved high response rates, the responses were transient with only 1/12 of patients retaining cosmetic control at median follow-up procedures of 9.5 months. Retreatment for failures after 8-10 Gy has also been unsatisfactory. Having shown that 24 Gy of external radiation therapy for benign parotid hypertrophy produced more durable cosmetic control than 8-10 Gy, we now report on longer follow-up periods on a group of patients receiving 24 Gy.

MATERIALS AND METHODS

Twenty +HIV patients with clinical and radiographic evidence of lymphoepithelial lesions of the parotid were treated with 24 Gy of external radiation therapy using daily 1.5 Gy fractions; parallel opposed technique and 6 MV photons were used in 19 patients, and unilateral electron treatment was performed for one patient.

RESULTS

With a mean follow-up period of 24 months, the cosmetic control appears durable. We have had no late failures past 24 months. Two patients have complained of modest xerostomia. There was no correlation with size of the cyst and eventual cosmetic result.

CONCLUSIONS

Twenty-four Gy produces durable parotid control for HIV associated lymphoepithelial lesions of the parotid glands in +HIV patients. Failures after 2 years are uncommon and the side effects have been tolerable.

A genetic screen for modifiers of E2F in Drosophila melanogaster

The activity of the E2F transcription factor is regulated in part by pRB, the protein product of the retinoblastoma tumor suppressor gene. Studies of tumor cells show that the p16(ink4a)/cdk4/cyclin D/pRB pathway is mutated in most forms of cancer, suggesting that the deregulation of E2F, and hence the cell cycle, is a common event in tumorigenesis. Extragenic mutations that enhance or suppress E2F activity are likely to alter cell-cycle control and may play a role in tumorigenesis. We used an E2F overexpression phenotype in the Drosophila eye to screen for modifiers of E2F activity. Coexpression of dE2F and its heterodimeric partner dDP in the fly eye induces S phases and cell death. We isolated 33 enhancer mutations of this phenotype by EMS and X-ray mutagenesis and by screening a deficiency library collection. The majority of these mutations sorted into six complementation groups, five of which have been identified as alleles of brahma (brm), moira (mor) osa, pointed (pnt), and polycephalon (poc). osa, brm, and mor encode proteins with homology to SWI1, SWI2, and SWI3, respectively, suggesting that the activity of a SWI/SNF chromatin-remodeling complex has an important impact on E2F-dependent phenotypes. Mutations in poc also suppress phenotypes caused by p21(CIP1) expression, indicating an important role for polycephalon in cell-cycle control.

The utility of bone scans in rheumatology

PURPOSE

Bone scanning is the most common diagnostic imaging service requested by Australian rheumatologists, who order $50,000 (Australian) worth of bone scans annually.

METHODS

To determine why rheumatologists request bone scans and how they affect their patient management, the authors administered a two-part prospective survey before and after every bone scan ordered by four rheumatologists during a 6-month period in 1996.

RESULTS

A total of 136 bone scans were requested. The primary indications for scanning were to confirm a clinical diagnosis (38%), to exclude a diagnosis (34%), and to localize the site of pain (17%). The common diseases that rheumatologists were attempting to confirm or exclude with bone scanning were inflammatory arthritis, malignancy, and fracture. However, the most common provisional and final diagnosis was soft tissue rheumatism (18%), followed by inflammatory arthritis (15%) and osteoarthritis (11%). Bone scans were successful in excluding a diagnosis in 87% and confirming a diagnosis in 80%. In 32%, bone scans altered the clinical diagnosis, and in 43% they changed the course of disease management. Bone scan results prevented further investigations in 60%.

A phase I clinical trial of prolonged infusion of hydroxyurea in combination with hyperfractionated, accelerated, external radiation therapy in patients with advanced squamous cell cancer of the head and neck

BACKGROUND

Preclinical data suggested that sustained inhibition of the anabolic enzyme, ribonucleotide reductase (RR), by hydroxyurea (HU) may be critical for the anticancer effects of the drug. A phase I trial of continuous infusion HU with concomitant hyperfractionated, accelerated radiation therapy (CHU-CHRT) was initiated to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLT) of HU in patients with locally advanced squamous cell carcinoma (SCC) of the head and neck.

METHODS

Patients were required to have histologically-documented and radiographically-staged locally advanced SCC of the hypopharynx (AJC stages II, III or IV), oropharynx (AJC stage IV), or oral cavity (AJC stage IV) not amenable to reasonable surgical resection. Eligible patients had adequate bone marrow, hepatic, and renal function and had to give informed consent. Concomitant, hyperfractionated, accelerated radiation therapy (CHRT) consisted of 1.2 Gy BID (6 hour minimum interfraction interval) on weekdays and 1.2 Gy delivered daily on the weekends to a total tumor dose of 74.4 Gy. Continuous infusion hydroxyurea (CHU) was administered at 0.25-0.375 mg/m2/min as a continuous intravenous infusion daily for 5 days with weekends days off for the duration of the radiation therapy. The dose of HU was increased by 0.125 mg/m2/min between dose levels until DLT was reached in 2/6 patients. If the primary had a complete clinical response and biopsies were negative, planned neck dissections were performed.

RESULTS

Fifteen patients were enrolled and are evaluable. The initial dose level, 0.25 mg/m2/min was tolerated by 3/3 patients. At 0.375 mg/m2/min, 3/6 patients experienced grade 3-4 infections, with one patient having a non-fatal, subendocardial infarction. At 0.313 mg/m2/min, no patient experienced DLT.

CONCLUSION

The MTD for CHU-CHRT was 0.313 mg/m2/min. The toxicities were primarily mucosal and a phase II study is in progress.

Psychological aspects of eye disorders

Images

Papillary endolymphatic sac tumors: CT, MR imaging, and angiographic findings in 20 patients

PURPOSE

To determine the computed tomographic (CT), magnetic resonance (MR) imaging, and angiographic findings of papillary endolymphatic sac tumors.

MATERIALS AND METHODS

Clinical and imaging studies in 20 patients (aged 17-65 years) with histopathologically proved papillary endolymphatic sac tumors were retrospectively reviewed. Patients underwent CT (n = 18), MR imaging (n = 15), or angiography (n = 12). CT scans were evaluated for bone erosion and calcification; MR images, for signal intensity, enhancement patterns, and flow voids; and angiograms, for tumoral blood supply.

RESULTS

All tumors were destructive and contained calcifications centered in the retrolabyrinthine region at CT. The MR imaging appearance varied with lesion size; 12 of 15 tumors showed increased signal intensity at T1-weighted imaging. The high-signal-intensity area was circumferential in lesions 3 cm or smaller and was scattered throughout the lesion in advanced tumors. Only tumors larger than 2 cm had flow voids. The blood supply arose predominantly from the external carotid artery. Large tumors had additional supply from the internal carotid and posterior circulation.

CONCLUSION

Papillary endolymphatic sac tumors are destructive, hypervascular lesions that arise from the temporal bone retrolabyrinthine region. Increased signal intensity at unenhanced T1-weighted MR imaging is common and may help distinguish these lesions from more common, aggressive temporal bone tumors.

The world according to hedgehog

Members of the Hedgehog family of signaling molecules mediate many important short- and long-range patterning processes during invertebrate and vertebrate development. In the fly, a single hedgehog gene regulates segmental and imaginal disc patterning. In contrast, in vertebrates a hedgehog gene family is involved in the control of left-right asymmetry, polarity in the central nervous system (CNS), somites and limb, organogenesis, chondrogenesis and spermatogenesis. Here, we review recent experiments addressing the function of the various Hedgehog members during invertebrate and vertebrate development.

E2F-induced S phase requires cyclin E

Both the heterodimeric transcription factor, E2F, and the G1 cyclin, cyclin E, are required for the G1-S transition at the start of the metazoan cell cycle. It has been established that cyclin E can act as an upstream activator of E2F. In addition to this action, we show here that cyclin E has an essential role in DNA replication distinct from activating E2F. We have created transgenic Drosophila capable of inducible, ectopic production of E2F activity. Simultaneous overexpression of both Drosophila E2F subunits, dE2F and dDP, in embryos stimulated the expression of multiple E2F-target genes including cyclin E, and also caused the initiation of S phase. Mutation of cyclin E prevented the initiation of S phase after overexpression of dE2F/dDP without affecting induction of target gene expression. Thus, E2F-directed transcription cannot bypass loss of cyclin E in Drosophila embryos.

Requirements for dE2F function in proliferating cells and in post-mitotic differentiating cells

The transcription factor E2F is a target of the retinoblastoma tumor suppressor protein (pRB) and may mediate pRB regulation of S phase entry in mammalian cells. The recent identification of mutant alleles of the Drosophila E2F gene (dE2F) has shown that dE2F is required for embryogenesis. dE2F-mutant embryos lack a co-ordinated program of gene expression which accompanies S phase entry and DNA synthesis declines to levels that are barely detectable. We have investigated the role of the dE2F gene at later stages of development. dE2F is expressed in several larval tissues and is required for cell proliferation in the eye imaginal disc. Surprisingly, dE2F expression persists in post-mitotic cells of the eye disc of third-instar larvae. The loss of dE2F function in these cells causes a novel phenotype, characterized by loss of photoreceptors and abnormal rhabdomere cell morphology. These results show that dE2F is required at multiple stages of development and suggest that E2F may have an important function in post-mitotic cells in addition to its role during cell proliferation.

The transcription factor E2F is required for S phase during Drosophila embryogenesis

Overexpression of the E2F-1 cDNA in mammalian cells disrupts normal control of the cell cycle and drives cells into S phase. Whereas eliminating E2F activity would test its inferred involvement in the G1-S transition, elimination is complicated by the existence of gene families encoding mammalian E2F. Here we identify mutations in a single essential Drosophila gene, dE2F, that encodes a homolog of the mammalian E2F gene family. Embryos homozygous for null mutations of dE2F complete early cell cycles, presumably using maternal contributions of gene products, but DNA synthesis falls to virtually undetectable levels in cycle 17. Mutant embryos also lack the pulses of coordinate transcription of genes encoding replication functions that usually accompany each transition from quiescence to S phase. We conclude that in most cells dE2F is essential for a G1-S transcriptional program and for G1-S progression.

Explanation in the hermeneutic science

Using clinical vignettes, we first examine the idea that psychoanalysis is, in Gill's (1991) phrase, a hermeneutic science--hermeneutic because it interprets meanings, scientific because the meaning connections it deals with are also usually causal connections. Next we explore some aspects of the structure of the kinds of explanation distinctive to psychoanalysis. Three kinds are distinguished: conveyance of content explanations, which have been central in the accounts of some recent philosophers of psychoanalysis, and two kinds of explanation in terms of intentionality, in terms, that is to say, of what the psychic states in question are about. One deals with forward-looking states such as wishes, in which the state is about some future, sought-after state of affairs such as a wish-fulfilment; the other deals with backward-looking psychic states such as memories, in which the state to be explained is about some earlier experience, fantasy, or whatever, one often quite unknown to the analysand prior to analysis. The paper concludes by making a quick case for the idea that good explanations in terms of meaning or intentionality often also identify the cause of the psychic states being explained.

DNA-binding and trans-activation properties of Drosophila E2F and DP proteins

The temporal activation of E2F transcriptional activity appears to be an important component of the mechanisms that prepare mammalian cells for DNA replication. Regulation of E2F activity appears to be a highly complex process, and the dissection of the E2F pathway will be greatly facilitated by the ability to use genetic approaches. We report the isolation of two Drosophila genes that can stimulate E2F-dependent transcription in Drosophila cells. One of these genes, dE2F, contains three domains that are highly conserved in the human homologs E2F-1, E2F-2, and E2F-3. Interestingly, one of these domains is highly homologous to the retinoblastoma protein (RB)-binding sequences of human E2F genes. The other gene, dDP, is closely related to the human DP-1 and DP-2 genes. We demonstrate that dDP and dE2F interact and cooperate to give sequence-specific DNA binding and optimal trans-activation. These features suggest that endogenous Drosophila E2F, like human E2F, may be composed of heterodimers and may be regulated by RB-like proteins. The isolation of these genes will provide important reagents for the genetic analysis of the E2F pathway.

Schopenhauer and Freud

A close study of Schopenhauer's central work, 'The World as Will and Representation', reveals that a number of Freud's most characteristic doctrines were first articulated by Schopenhauer. A thinker always expresses something of his culture, of course, but the parallels to be found between Freud and Schopenhauer go well beyond cultural influence. Schopenhauer's concept of the will contains the foundations of what in Freud became the concepts of the unconscious and the id. Schopenhauer's writings on madness anticipate Freud's theory of repression and his first theory of the aetiology of neurosis. Schopenhauer's work contains aspects of what become the theory of free association. And most importantly, Schopenhauer articulates major parts of the Freudian theory of sexuality. These correspondences raise some interesting questions about Freud's denial that he even read Schopenhauer until late in life.

Bowel distress and emotional conflict

A psychodynamic assessment of 60 women with functional bowel disorder seen at St Mark's, a specialist hospital for disorders of the colon and rectum, has shown that most were trapped in severe emotional conflicts with which they were unable to cope. In many the bodily illnesses appeared to be an expression of these conflicts as well as a defence against experiencing them. The illnesses were then partly, or entirely, emotional conflicts that had become medicalized--emotional conflicts in illnesses clothing. The illnesses, usually precipitated by significant life events, often had their roots in emotional conflicts in infancy or childhood at which time a high proportion of the women had experienced a severe life trauma. The study also indicated that the conflicts that appeared to contribute to the illnesses were associated with emotional difficulties in fulfilling themselves as women.

The consequences of marijuana use on intrapersonal and interpersonal functioning in black and white adolescents

We examined the effects of marijuana use on adolescent personality, attitudinal, and behavioral attributes, perceived parent-adolescent relations, and perceived peer factors. Volunteer high school students (292 Blacks, 401 Whites) of middle-class backgrounds filled out questionnaires in their classrooms first when they were in the 9th and 10th grades and again 2 years later when they were in the 11th and 12th grades. Results suggest that regular use of marijuana may lead to lower achievement, increased tolerance of deviance, and more deviant behavior, and greater rebelliousness. Regular use also appears to interfere with adolescents' relationships with their parents and to lead them to associate with more deviant and drug-using friends. The consequences of marijuana use for intrapersonal and interpersonal functioning were for the most part similar in the different sex and age groups, although there were some ethnic differences.

Streptococcus faecalis arthritis

Septic arthritis due to Streptococcus faecalis is rare. We describe a case in which synovial biopsy was required for diagnosis and a new longterm antibiotic combination using ciprofloxacin and amoxicillin was successful in treating the infection. Comparison is made with previous reported cases and the usual poor outcome in this condition.