The Clinical Implications of Reversions in Patients with Advanced Pancreatic Cancer and Pathogenic Variants in BRCA1, BRCA2, or PALB2 after Progression on Rucaparib

PURPOSE

PARP inhibitors (PARPi) provide an effective maintenance option for patients with BRCA- or PALB2-mutated pancreatic cancer. However, mechanisms of PARPi resistance and optimal post-PARPi therapeutic strategies are poorly characterized.

EXPERIMENTAL DESIGN

We collected paired cell-free DNA samples and post-PARPi clinical data on 42 patients with advanced, platinum-sensitive pancreatic cancer who were treated with maintenance rucaparib on NCT03140670, of whom 32 developed progressive disease.

RESULTS

Peripherally detected, acquired BRCA or PALB2 reversion variants were uncommon (5/30; 16.6%) in patients who progressed on rucaparib. Reversions were significantly associated with rapid resistance to PARPi treatment (median PFS, 3.7 vs. 12.5 months; P = 0.001) and poor overall survival (median OS, 6.2 vs. 23.0 months; P < 0.0001). All patients with reversions received rechallenge with platinum-based chemotherapy following PARPi progression and experienced faster progression on this therapy than those without reversion variants (real-world time-to-treatment discontinuation, 2.4 vs. 5.8 months; P = 0.004). Of the patients who progressed on PARPi and received further chemotherapy, the OS from initiation of second-line therapy was significantly lower in those with reversion variants than in those without (5.5 vs. 12.0 months, P = 0.002). Finally, high levels of tumor shedding were independently associated with poor outcomes in patients who received rucaparib.

CONCLUSIONS

Acquired reversion variants were uncommon but detrimental in a population of patients with advanced BRCA- or PALB2-related pancreatic ductal adenocarcinoma who received maintenance rucaparib. Reversion variants led to rapid progression on PARPi, rapid failure of subsequent platinum-based treatment, and poor OS of patients. The identification of such variants in the blood may have both predictive and prognostic value. See related commentary by Tsang and Gallinger, p. 5005.

High Thermal Conductivity of Submicrometer Aluminum Nitride Thin Films Sputter-Deposited at Low Temperature

Aluminum nitride (AlN) is one of the few electrically insulating materials with excellent thermal conductivity, but high-quality films typically require exceedingly hot deposition temperatures (>1000 °C). For thermal management applications in dense or high-power integrated circuits, it is important to deposit heat spreaders at low temperatures (<500 °C), without affecting the underlying electronics. Here, we demonstrate 100 nm to 1.7 μm thick AlN films achieved by low-temperature (<100 °C) sputtering, correlating their thermal properties with their grain size and interfacial quality, which we analyze by X-ray diffraction, transmission X-ray microscopy, as well as Raman and Auger spectroscopy. Controlling the deposition conditions through the partial pressure of reactive N2, we achieve an ∼3× variation in thermal conductivity (∼36-104 W m-1 K-1) of ∼600 nm films, with the upper range representing one of the highest values for such film thicknesses at room temperature, especially at deposition temperatures below 100 °C. Defect densities are also estimated from the thermal conductivity measurements, providing insight into the thermal engineering of AlN that can be optimized for application-specific heat spreading or thermal confinement.

Extended X-ray absorption fine structure of dynamically-compressed copper up to 1 terapascal

Large laser facilities have recently enabled material characterization at the pressures of Earth and Super-Earth cores. However, the temperature of the compressed materials has been largely unknown, or solely relied on models and simulations, due to lack of diagnostics under these challenging conditions. Here, we report on temperature, density, pressure, and local structure of copper determined from extended x-ray absorption fine structure and velocimetry up to 1 Terapascal. These results nearly double the highest pressure at which extended x-ray absorption fine structure has been reported in any material. In this work, the copper temperature is unexpectedly found to be much higher than predicted when adjacent to diamond layer(s), demonstrating the important influence of the sample environment on the thermal state of materials; this effect may introduce additional temperature uncertainties in some previous experiments using diamond and provides new guidance for future experimental design.

Analysis of BRCA1- and BRCA2-Related Pancreatic Cancer and Survival

This cohort study compares the outcomes of patients with BRCA1 and BRCA-related pancreatic cancers using 2 large data sets.

Patterned Adhesion Layer Enables Rugged Pd-MIS Hydrogen Sensors

Rugged Pd-metal-insulator-semiconductor (Pd-MIS) hydrogen sensors for detecting charge-exchange particles in fusion reactors have been constructed by utilizing a novel patterned adhesion layer. Poor adhesion at the interface between Pd and SiO2 is a common failure mode for Pd-MIS devices, severely limiting the Pd thickness and their usefulness as hydrogen sensors. The mechanical integrity of the Pd coatings is of particular importance in magnetic fusion energy research where the Pd-MIS diodes are used to measure hydrogen charge-exchange neutral fluence at the wall in tokamaks. In this application, particularly thick Pd contacts are desirable to prevent damage caused by high-energy particles; however, such thick Pd coatings are prone to mechanical failure due to blistering and wire bond detachment during construction or operation. A continuous Ti or Cr adhesion layer is not possible for this application since it would interfere with H uptake at the SiO2 interface, which is essential for the device to generate a response. In this work, we demonstrate that a patterned Cr interlayer substantially improves adhesion while still providing access for hydrogen to reach the SiO2-Pd interface.

Anesthetic Management of Renal Cell Carcinoma With Level 3 Inferior Vena Cava Extension in a Patient With Severe Coronary Artery Disease

A 49-year-old male with untreated type 2 diabetes and a family history of coronary artery disease (CAD) presented with right flank pain and profound progressive dyspnea on exertion to the emergency department of Ben Taub Hospital, a tertiary county hospital. Workup revealed right renal cell carcinoma with metastatic extension into the inferior vena cava (IVC). In addition, the patient had significant CAD with 95% occlusion of the proximal left anterior descending coronary artery amenable to percutaneous coronary intervention (PCI). After multidisciplinary discussions involving cardiovascular anesthesiology, cardiology, urology, and cardiothoracic surgery, it was estimated that the mortality benefit of immediate tumor resection outweighed the patient's need for PCI and further cardiac optimization. The patient underwent curative resection and thrombectomy under transesophageal echocardiography (TEE) guidance without complication, made an expedient recovery, and was discharged home on postoperative day seven.

TIPE2 Promotes Tumor Initiation But Inhibits Tumor Progression in Murine Colitis-Associated Colon Cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer in the United States, and inflammatory bowel disease patients have an increased risk of developing CRC due to chronic intestinal inflammation with it being the cause of death in 10% to 15% of inflammatory bowel disease patients. TIPE2 (TNF-alpha-induced protein 8-like 2) is a phospholipid transporter that is highly expressed in immune cells and is an important regulator of immune cell function.

METHODS

The azoxymethane/dextran sulfate sodium murine model of colitis-associated colon cancer (CAC) was employed in Tipe2 -/- and wild-type mice, along with colonoid studies, to determine the role of TIPE2 in CAC.

RESULTS

Early on, loss of TIPE2 led to significantly less numbers of visible tumors, which was in line with its previously described role in myeloid-derived suppressor cells. However, as time went on, loss of TIPE2 promoted tumor progression, with larger tumors appearing in Tipe2 -/- mice. This was associated with increased interleukin-22/STAT3 phosphorylation signaling. Similar effects were also observed in primary colonoid cultures, together demonstrating that TIPE2 also directly regulated colonocytes in addition to immune cells.

CONCLUSIONS

This work demonstrates that TIPE2 has dual effects in CAC. In the colonocytes, it works as a tumor suppressor. However, in the immune system, TIPE2 may promote tumorigenesis through suppressor cells or inhibit it through IL-22 secretion. Going forward, this work suggests that targeting TIPE2 for CRC therapy requires cell- and pathway-specific approaches and serves as a cautionary tale for immunotherapy approaches in general in terms of colon cancer, as intestinal inflammation can both promote and inhibit cancer.

TNFAIP8 Regulates Intestinal Epithelial Cell Differentiation and May Alter Terminal Differentiation of Secretory Progenitors

The intestine is a highly proliferative dynamic environment that relies on constant self-renewal of the intestinal epithelium to maintain homeostasis. Tumor necrosis factor-alpha-induced protein 8 (TNFAIP8 or TIPE0) is a regulator of PI3K-mediated signaling. By binding to PIP2 and PIP3, TIPE family members locally activate PI3K activity while globally inhibiting PI3K activity through sequestration of membranous PIP2. Single-cell RNA sequencing survey of Tipe0-/- small intestine was used to investigate the role of TIPE0 in intestinal differentiation. Tipe0-/- intestinal cells were shown to shift towards an undifferentiated state, with the notable exception of goblet cells. Additionally, three possible novel regulators of terminal cell fate decisions in the secretory lineage were identified: Nupr1, Kdm4a, and Gatad1. We propose that these novel regulators drive changes involved in goblet cell (Nupr1) or tuft cell (Kdm4a and Gatad1) fate commitment and that TIPE0 may play a role in orchestrating terminal differentiation.

Pregnancy loss in beef cattle: A meta-analysis

Pregnancy loss in beef cattle causes both management and economic challenges to a producer. A meta-analysis was conducted to quantify reproductive failures that occur during fertilization, early embryonic development, and late embryonic/early fetal development periods of gestation in beef cattle. The meta-analysis included more than 56,000 diagnostic records in 159 studies from 48 papers with 12 studies included in fertilization and pre- blastocyst loss analysis (FERT; days 1-7 of gestation), 107 in early embryo (EEM; days 7-32), and 40 in late embryo/early fetal period (LEF; days 32-100) analysis. Although fertilization rates are reportedly high in beef cattle, significant developmental failure occurs within the first 7 days of gestation. Approximately 28.4 % of embryos will not develop past day 7 of gestation with most embryonic losses occurring before day 4. By the conclusion of the first month of gestation, 47.9 % of cows submitted to a single insemination at day 0 will not be pregnant. Overall, LEF between days 32-60 and 100 was 5.8 %. Bos indicus animals had greater (P =  0.001) EEM compared to Bos taurus, but there was no difference (P =  0.39) for the LEF period between subspecies. Primiparous cows had greater EEM (P =  0.002) compared to nulliparous heifers and multiparous cows; and nulliparous heifers had a greater LEF compared to primiparous and multiparous cows (P =  0.048). Collectively, these cumulative findings provide a baseline assessment of pregnancy loss specific to beef cattle.

Climate relationships to fecal bacterial densities in Maryland shellfish harvest waters

Coastal states of the United States (US) routinely monitor shellfish harvest waters for types of bacteria that indicate the potential presence of fecal pollution. The densities of these indicator bacteria in natural waters may be related to climate in several ways, including through runoff from precipitation and survival related to water temperatures. The relationship between interannual precipitation and air temperature patterns and the densities of fecal indicator bacteria in shellfish harvest waters in Maryland's portion of the Chesapeake Bay was quantified using 34 years of data (1979-2013). Annual and seasonal precipitation totals had a strong positive relationship with average fecal coliform levels (R(2) = 0.69) and the proportion of samples with bacterial densities above the FDA regulatory criteria (R(2) = 0.77). Fecal coliform levels were also significantly and negatively related to average annual air temperature (R(2) = -0.43) and the average air temperature of the warmest month (R(2) = -0.57), while average seasonal air temperature was only significantly related to fecal coliform levels in the summer. River and regional fecal coliform levels displayed a wide range of relationships with precipitation and air temperature patterns, with stronger relationships in rural areas and mainstem Bay stations. Fecal coliform levels tended to be higher in years when the bulk of precipitation occurred throughout the summer and/or fall (August to September). Fecal coliform levels often peaked in late fall and winter, with precipitation peaking in summer and early fall. Continental-scale sea level pressure (SLP) analysis revealed an association between atmospheric patterns that influence both extratropical and tropical storm tracks and very high fecal coliform years, while regional precipitation was found to be significantly correlated with the Atlantic Multidecadal Oscillation and the Pacific North American Pattern. These findings indicate that management of shellfish harvest waters should account for changes in climate conditions and that SLP patterns may be particularly important for predicting years with extremely high levels of fecal coliforms.

Gender-specific Effects of Treatment with Lifestyle, Metformin or Sulfonylurea on Glycemic Control and Body Weight: A German Multicenter Analysis on 9 108 Patients

Effects of diabetes treatment are strongly connected to individual factors, but the relevant role of gender has not been addressed so far. This observational study evaluates whether monotherapy with lifestyle, metformin or sulfonylurea has gender-specific effects on glycemic control and/or body weight. Data of 9 108 patients with type 2 diabetes from 129 German diabetes centers were assessed by a standardized, prospective, computer-based diabetes care and outcome documentation system (DPV-Wiss-database; age 63.1±12.8 years, diabetes duration 5.7±7.4 years, HbA1c 55±17.7 mmol/mol [7.2±1.6%], BMI 30.6±6.1 kg/m(2), 49.3% female patients). Antidiabetic concepts included lifestyle intervention (n=5,787), metformin (n=2,180), sulfonylurea (n=943) or other antidiabetic drugs (n=198), respectively. HbA1c and body weight were compared before and after a stable monotherapeutical period of 0.8±0.4 years. Women had a significantly higher reduction of body weight after treatment with lifestyle (women-0.8±0.1 vs. men-0.2±0.1 kg; p<0.05), metformin (women-1.8±0.2 vs. men-1.2±0.2 kg; p<0.05) or sulfonylurea drugs (women-0.9±0.2 vs. men - 0.1±0.2 kg; p<0.05), whereas men displayed significantly higher HbA1c-reductions after treatment with lifestyle (women-6.9±0.2 mmol/mol [- 0.6±0.02%] vs. men-7.5±0.2 mmol/mol [0.7±0.02%]; p<0.05) and metformin only (women-6.3±0.3 mmol/mol [- 0.6±0.03%] vs. men - 7.4±0.3 mmol/mol [- 0.7±0.03%]; p<0.05). No differences were seen for sulfonylurea monotherapy concerning the HbA1c-reduction (women - 5.6±0.5 mmol/mol [- 0.5±0.05%] vs. men-6.4±0.4 mmol/mol [- 0.6±0.04%]; p=0.196). In summary, antidiabetic treatment concepts might result in gender-specific effects on body weight and HbA1c. Gender might therefore represent another important factor in the context of an individualized treatment management of type 2 diabetes.

Perfusion computed tomography thresholds defining ischemic penumbra and infarct core: studies in a rat stroke model

BACKGROUND

Perfusion computed tomography is becoming more widely used as a clinical imaging tool to predict potentially salvageable tissue (ischemic penumbra) after ischemic stroke and guide reperfusion therapies.

AIMS

The study aims to determine whether there are important changes in perfusion computed tomography thresholds defining ischemic penumbra and infarct core over time following stroke.

METHODS

Permanent middle cerebral artery occlusion was performed in adult outbred Wistar rats (n = 6) and serial perfusion computed tomography scans were taken every 30 mins for 2 h. To define infarction thresholds at 1 h and 2 h post-stroke, separate groups of rats underwent 1 h (n = 6) and 2 h (n = 6) of middle cerebral artery occlusion followed by reperfusion. Infarct volumes were defined by histology at 24 h. Co-registration with perfusion computed tomography maps (cerebral blood flow, cerebral blood volume, and mean transit time) permitted pixel-based analysis of thresholds defining infarction, using receiver operating characteristic curves.

RESULTS

Relative cerebral blood flow was the perfusion computed tomography parameter that most accurately predicted penumbra (area under the curve = 0.698) and also infarct core (area under the curve = 0.750). A relative cerebral blood flow threshold of < 75% of mean contralateral cerebral blood flow most accurately predicted penumbral tissue at 0.5 h (area under the curve = 0.660), 1 h (area under the curve = 0.659), 1.5 h (area under the curve = 0.636), and 2 h (area under the curve = 0.664) after stroke onset. A relative cerebral blood flow threshold of < 55% of mean contralateral most accurately predicted infarct core at 1 h (area under the curve = 0.765) and at 2 h (area under the curve = 0.689) after middle cerebral artery occlusion.

CONCLUSIONS

The data provide perfusion computed tomography defined relative cerebral blood flow thresholds for infarct core and ischemic penumbra within the first two hours after experimental stroke in rats. These thresholds were shown to be stable to define the volume of infarct core and penumbra within this time window.

Functional expression of a GFP-tagged Kv1.5 alpha-subunit in mouse ventricle

The experiments here were undertaken to determine the feasibility of increasing the cell surface expression of voltage-gated ion channels in cardiac cells in vivo and to explore the functional consequences of ectopic channel expression. Transgenic mice expressing a green fluorescent protein (GFP)-tagged, voltage-gated K+ (Kv) channel alpha-subunit, Kv1.5-GFP, driven by the cardiac-specific alpha-MHC promoter, were generated. In recent studies, Kv1.5 has been shown to encode the micromolar 4-aminopyridine (4-AP)-sensitive delayed rectifier K+ current (I(K,slow)) in mouse myocardium. Unexpectedly, Kv1.5-GFP expression is heterogeneous in the ventricles of these animals. Although no electrocardiographic abnormalities were evident, expression of Kv1.5-GFP results in marked decreases in action potential durations in GFP-positive ventricular myocytes. In voltage-clamp recordings from GFP-positive ventricular myocytes, peak outward K+ currents are significantly higher, and their waveforms are distinct from those recorded from wild-type cells. Pharmacological experiments revealed a selective increase in a micromolar 4-AP-sensitive current, similar to the 4-AP-sensitive component of I(K,slow) in wild-type cells. The inactivation rate of the "overexpressed" current, however, is significantly slower than the Kv1.5-encoded component of I(K,slow) in wild-type cells, suggesting differences in association with accessory subunits and/or posttranslational processing.

Human granulocytic ehrlichiosis in Northern California: two case descriptions with genetic analysis of the Ehrlichiae

We report two cases of human granulocytic ehrlichiosis (HGE) that occurred in northern California in summer 1998. Patients had fever, malaise, and myalgia, reported tick bites, had moderate thrombocytopenia, and had normal or slightly elevated liver enzyme activities. Ehrlichial inclusions were observed in the blood of one patient, and HGE-agent DNA was amplified by PCR from both patients. Genetically, the strains resembled horse isolates from northern California. The close spatial and temporal proximity of the two new cases may be due to a nidus of infection in the area or heightened surveillance by local physicians.

Genome-scale cloning and expression of individual open reading frames using topoisomerase I-mediated ligation

The in vitro cloning of DNA molecules traditionally uses PCR amplification or site-specific restriction endonucleases to generate linear DNA inserts with defined termini and requires DNA ligase to covalently join those inserts to vectors with the corresponding ends. We have used the properties of Vaccinia DNA topoisomerase I to develop a ligase-free technology for the covalent joining of DNA fragments to suitable plasmid vectors. This system is much more efficient than cloning methods that require ligase because the rapid DNA rejoining activity of Vaccinia topoisomerase I allows ligation in only 5 min at room temperature, whereas the enzyme's high substrate specificity ensures a low rate of vector-alone transformants. We have used this topoisomerase I-mediated cloning technology to develop a process for accelerated cloning and expression of individual ORFs. Its suitability for genome-scale molecular cloning and expression is demonstrated in this report.

Theory of the oscillometric maximum and the systolic and diastolic detection ratios

It is proposed that the maximum in cuff pressure oscillations during oscillometry is due to the buckling of the brachial artery under a cuff. This theory is investigated by means of a mathematical model of oscillatometry that includes the mechanics of the occlusive arm cuff, the arterial pressure pulse waveform, and the mechanics of the brachial artery. A numerical solution is provided for the oscillations in cuff pressure for one cycle of cuff inflation and deflation. The buckling pressure is determined from actual arterial data and the von Mises buckling criteria. The buckling of an artery under a cuff occurs near -2 to 0 mm Hg transmural pressure. This effect corresponds with a maximum arterial compliance and maximum cuff pressure oscillations when cuff pressure is nearly equal to mean arterial pressure (MAP), in support of the suggested theory. The model was also found to demonstrate the basic characteristics of experimental oscillometry, such as an increasing and decreasing amplitude in oscillations as cuff pressure decreases, the oscillations that occur when cuff pressure is above systolic pressure, maximum oscillation amplitudes in the range of 1 to 4 mm Hg, and an oscillatory maximum at cuff pressure equal to MAP. These findings support the case that the model is representative of oscillometry. Finally, the model predicted values for the systolic and diastolic detection ratios of 0.593 and 0.717, respectively, similar to those found empirically. These ratios alter with blood pressure, but the tightness of the cuff wrap did not change their value.

Mechanics of the occlusive arm cuff and its application as a volume sensor

Although a common medical instrument, the mechanical function of an occlusive arm cuff has not been fully described in an engineering sense. The occlusive arm cuff is examined here using a mathematical mechanics model and experimental measurements. Cuff stretch was modeled by a nonlinear pressure-volume function. Air compression was represented by Boyle's law. An apparatus was developed to measure pressure due to the air volume pumped into the cuff for fixed arm volume. Data were obtained for two different cuff designs, and reveal a nonlinear cuff pressure-volume relationship that could be represented accurately by the mathematical model. Calibration constants are provided for the two types of occlusive cuff. Thus, the cuff pressure was found to consist of a balance between that produced by stretch of the elastic cuff bladder and that of the compression of the air contained within the bladder. The use of the gas law alone was found to be inadequate to represent the cuff mechanics. When applying the cuff to measure change in arm volume, such as during plethysmography or oscillometry, it cannot be assumed that the cuff sensitivity is constant. More precisely, it was found that the occlusive cuff is a transducer with a volume sensitivity that increases with cuff pressure and volume until it becomes nearly constant at high levels of cuff pressure (150 mmHg). A hypothetical case of a linear elastic artery with constant pulse pressure was used as input to the cuff model to illustrate the change in cuff pressure oscillations that occurs while cuff pressure is released.(ABSTRACT TRUNCATED AT 250 WORDS)

Health knowledge and beliefs as predictors of intended condom use among Zimbabwean adolescents in probation/remand homes

The association of AIDS knowledge, perceived susceptibility to HIV, efficacy of preventive measures, severity of HIV infection, cues to action, barriers to action and alcohol/drug use with intended condom use was examined among Zimbabwean adolescents (mean age = 16.9) in probation/remand homes. Eighty-six percent of males and 83% of females were reportedly sexually experienced of whom 28% of males and 14% of females reported consistent condom use. Those who knew that babies can be born with AIDS, that there is no vaccine against HIV and that traditional healers cannot cure AIDS were 2.50, 2.32 and 1.97 times as likely to definitely intend to use condoms. Individuals who believed condoms seldom break or leak and are effective against HIV were 4.12 and 4.65 times as likely to definitely intend to use them. Those who believed parents and boyfriend/girlfriends thought condoms should be used were 2.27 and 2.13 times as likely to intend to use them. Respondents who had talked about AIDS with friends, with their boyfriend/girlfriend or a schoolteacher or seen a picture or film of a PWA were, in comparison to those who had not engaged in these actions, 3.70, 2.33, 2.43 and 2.50 times as likely to definitely intend to use condoms. Those who were embarrassed to get condoms from a clinic, thought persons who use condoms are loose and or that the pleasure of unprotected sex was worth the risk of HIV were 3.87, 3.42 and 3.40 times as likely to intend to use condoms. Logistic regression identified belief in efficacy of condoms as the principal predictor of intended condom use.(ABSTRACT TRUNCATED AT 250 WORDS)

New polyester arterial prostheses from Great Britain: an in vitro and in vivo evaluation

Two models of knitted velour polyester prostheses have been developed in Great Britain, i.e. the VP1200K and the VP50K Triaxial. The evaluation of these new devices in vitro and in vivo in dogs has demonstrated that, while the first model has similar surgical, mechanical and healing characteristics in the short term to other commercial knitted velour prostheses, the second model has lower water permeability and superior strength and dimensional stability. On the basis of these results, clinical investigations can be undertaken.

Epstein-Barr virus transcription in nasopharyngeal carcinoma

Sequences which encode Epstein-Barr virus (EBV) RNA in nasopharyngeal carcinoma (NPC) tissue have been identified. We utilized human biopsy material directly as well as NPC grown in nude mice. Total RNA was extracted from the tumor material and separated into polyadenylated and nonpolyadenylated fractions by oligodeoxythymidylate-cellulose chromatography. This material was used as template to construct 32P-labeled cDNA. The labeled cDNAs were hybridized to Southern blots of recombinant EBV DNA fragments. Three of the biopsies, F, 49, and 55, contained polyadenylated RNA homologous to the EBV BamHI fragments V and K, and EcoRI-DIJhet. These same fragments encode the most abundant polyribosomal RNAs in latently infected lymphoblastoid cell lines. The sequences which encoded nonpolyadenylated RNA in NPC tumor 49 were more extensive and included BamHI fragments C, V, B, E, and K, and EcoRI fragments DIJhet, E, F, and G1, a result that indicates selective polyadenylation in EBV RNA processing. A fourth biopsy, NPC tumor 18, contained polyadenylated RNA homologous to the BamHI fragments H, B, K, Y, B1, I1, and A and EcoRI fragments F and G2. A similar pattern of transcription was identified in three tumor specimens from nude mice, 4, 5, and 8. Transformation of lymphocytes did not occur after cocultivation in vitro with explants from these nude mice tumors. This transcriptional pattern may represent an activated state of the EBV genome, formerly not detected in tumor tissue, which is analogous to the state of abortive infection identified in induced in vitro cell systems.

Lower extremity amputation for ischemia

Three hundred-twenty-four amputations of the lower extremity for ischemia at the University of Oregon Health Sciences Center over the past ten years are presented. Striking differences between the first and second five-year periods are noted in level of amputation. The primary healing rate of all patients in the two periods was similar. Diabetics tended to have more distal amputations but primary healing was lower than that of nondiabetics.