Development and Validation of Machine Learning Algorithms to Predict 1-Year Ischemic Stroke and Bleeding Events in Patients with Atrial Fibrillation and Cancer

In this study, we leveraged machine learning (ML) approach to develop and validate new assessment tools for predicting stroke and bleeding among patients with atrial fibrillation (AFib) and cancer. We conducted a retrospective cohort study including patients who were newly diagnosed with AFib with a record of cancer from the 2012-2018 Surveillance, Epidemiology, and End Results (SEER)-Medicare database. The ML algorithms were developed and validated separately for each outcome by fitting elastic net, random forest (RF), extreme gradient boosting (XGBoost), support vector machine (SVM), and neural network models with tenfold cross-validation (train:test = 7:3). We obtained area under the curve (AUC), sensitivity, specificity, and F2 score as performance metrics. Model calibration was assessed using Brier score. In sensitivity analysis, we resampled data using Synthetic Minority Oversampling Technique (SMOTE). Among 18,388 patients with AFib and cancer, 523 (2.84%) had ischemic stroke and 221 (1.20%) had major bleeding within one year after AFib diagnosis. In prediction of ischemic stroke, RF significantly outperformed other ML models [AUC (0.916, 95% CI 0.887-0.945), sensitivity 0.868, specificity 0.801, F2 score 0.375, Brier score = 0.035]. However, the performance of ML algorithms in prediction of major bleeding was low with highest AUC achieved by RF (0.623, 95% CI 0.554-0.692). RF models performed better than CHA2DS2-VASc and HAS-BLED scores. SMOTE did not improve the performance of the ML algorithms. Our study demonstrated a promising application of ML in stroke prediction among patients with AFib and cancer. This tool may be leveraged in assisting clinicians to identify patients at high risk of stroke and optimize treatment decisions.

Benefit and risk of oral anticoagulant initiation strategies in patients with atrial fibrillation and cancer: a target trial emulation using the SEER-Medicare database

Oral anticoagulants (OACs) are recommended for patients with atrial fibrillation (AFib) having CHA2DS2-VASc score ≥ 2. However, the benefits of OAC initiation in patients with AFib and cancer at different levels of CHA2DS2-VASc is unknown. We included patients with new AFib diagnosis and a record of cancer (breast, prostate, or lung) from the 2012-2019 Surveillance, Epidemiology, and End Results (SEER)-Medicare database (n = 39,915). Risks of stroke and bleeding were compared between 5 treatment strategies: (1) initiated OAC when CHA2DS2-VASc ≥ 1 (n = 6008), (2) CHA2DS2-VASc ≥ 2 (n = 8694), (3) CHA2DS2-VASc ≥ 4 (n = 20,286), (4) CHA2DS2-VASc ≥ 6 (n = 30,944), and (5) never initiated OAC (reference group, n = 33,907). Confounders were adjusted using inverse probability weighting through cloning-censoring-weighting approach. Weighted pooled logistic regressions were used to estimate treatment effect [hazard ratios (HRs) and 95% confidence interval (95% CIs)]. We found that only patients who initiated OACs at CHA2DS2-VASc ≥ 6 had lower risk of stroke compared without OAC initiation (HR 0.64, 95% CI 0.54-0.75). All 4 active treatment strategies had reduced risk of bleeding compared to non-initiators, with OAC initiation at CHA2DS2-VASc ≥ 6 being the most beneficial strategy (HR = 0.49, 95% CI 0.44-0.55). In patients with lung cancer or regional/metastatic cancer, OAC initiation at any CHA2DS2-VASc level increased risk of stroke and did not reduce risk of bleeding (except for Regimen 4). In conclusion, among cancer patients with new AFib diagnosis, OAC initiation at higher risk of stroke (CHA2DS2-VASc score ≥ 6) is more beneficial in preventing ischemic stroke and bleeding. Patients with advanced cancer or low life-expectancy may initiate OACs when CHA2DS2-VASc score ≥ 6.

Factors associated with adherence to medications for lowering breast cancer risk between female Medicare beneficiaries in Alabama and nationwide

PURPOSE

The U.S. Preventive Services Task Force recommends use of selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) for breast cancer (BC) prevention. We examined factors associated with adherence to SERMs/AI treatments among female Medicare beneficiaries in Alabama and those nationwide.

METHODS

This retrospective new user cohort study analyzed the 2013-2016 Medicare administrative claims data files (100% Alabama and random 5% national samples). Female Medicare beneficiaries without invasive BC and osteoporosis, continuously enrolled in Medicare Parts A, B, and D for at least 18 months (with a 6-month washout and a 12-month follow-up period) in 2013-2016. Among beneficiaries who initiated (6-month washout) any of the SERMs/AIs (tamoxifen, raloxifene, anastrozole, and exemestane), we examined their 1-year treatment adherence using proportion of days covered (PDC) and operationalized as both continuous (0-1) and dichotomized (≥ 80% as adherent and < 80% as non-adherent) outcomes. Multivariable logistic models were used to identify factors associated with adherence (PDC ≥ 80%) among Alabama and national samples, respectively.

RESULTS

A total of 885 women in Alabama and 1,213 women in national sample initiated these SERMs/AI treatments. Among those with ≥ 2 prescriptions (n = 479 in Alabama and n = 870 in national sample), Mean PDC was 0.74 [standard deviation (SD) = 0.30] among Alabamian women, similar to those in the national sample [0.71 (SD = 0.31), p = 0.09]. Use of mammography prior to treatment initiation was associated with higher likelihood of adherence to treatments in both samples.

CONCLUSION

Our findings highlight the importance of access to preventive services such as mammography to better adherence to BC preventive treatments among female Medicare beneficiaries.

Screening for clinically relevant drug-drug interactions between direct oral anticoagulants and antineoplastic agents: a pharmacovigilance approach

BACKGROUND

Use of direct oral anticoagulants (DOACs) in patients with cancer remains suboptimal due to the concern regarding potential drug-drug interactions (DDIs) with antineoplastic treatments. However, the clinical relevance of these DDIs is unknown.

METHODS

We conducted a pharmacovigilance study of adverse event (AE) reports from the US Food and Drug Administration Adverse Event Reporting System from 1/1/2004 to 12/31/2021. AE reports containing DOACs and antineoplastic agents with CYP3A4/P-gp inhibitory or inducing activity suggested by published pharmacokinetic studies were included (n = 36,066). The outcomes of interest were bleeding or stroke, identified by MedDRA dictionary version 25.0. We used disproportionality analyses (DPA), logistic regression models (LR), and Multi-item Gamma-Poisson Shrinker (MGPS) (Empirical Bayes Geometric Means (EBGM) and 90% credible intervals (90% CIs)) algorithms to identify the safety signal of DDIs.

RESULTS

The highest bleeding reporting rates for each drug class were the combination of DOACs with neratinib (39.08%, n = 34), tamoxifen (21.22%, n = 104), irinotecan (20.54%, n = 83), and cyclosporine (19.17%, n = 227). The highest rate of stroke was found for prednisolone (2.43%, n = 113). In the primary analysis, no signal of DDIs by the antineoplastic therapeutic class was detected by MGPS, DPA, and LR approaches. By individual antineoplastic drug, DOACs-neratinib was the only signal detected [EBGM (EB05-EB95) = 2.71 (2.03-3.54)].

CONCLUSION

No signal of DDIs between DOACs and antineoplastic agents was detected, except for DOAC-neratinib. Most DDIs between DOACs and antineoplastic agents may not be clinically relevant. The DDIs between DOACs and neratinib should be further examined in future research.

Use of second-generation antidiabetic medication among a nationally representative sample

OBJECTIVES

Existing studies have shown the benefits of second-generation antidiabetic medications in patients with type 2 diabetes (T2D). However, the medications' real-world utilization was not well understood. Our study assessed patient factors associated with the use of second-generation antidiabetic medications in a nationally representative sample of patients with T2D.

STUDY DESIGN

This retrospective, cross-sectional analysis used the 2005 to 2018 National Health and Nutrition Examination Survey (NHANES) data.

METHODS

Survey participants 18 years and older who had a diagnosis of T2D and had used antidiabetic medications in the past 30 days were included. The primary outcome was the prescription of any second-generation antidiabetic medication. Weighted stepwise multivariable logistic regression models were used to assess the associations between the use of second-generation antidiabetic medications and patients' characteristics.

RESULTS

Among 4493 patients with T2D, 533 (weighted %, 13.67%) reported using at least 1 second-generation antidiabetic drug. In multivariable analyses, patients with incomes at least 400% of the federal poverty level (adjusted odds ratio [AOR], 2.30; 95% CI, 1.58-3.34), with higher hemoglobin A1c levels (AOR, 1.10; 95% CI, 1.02-1.18), and taking more medications (AOR, 1.14; 95% CI, 1.09-1.20) were more likely to use second-generation antidiabetic drugs compared with their counterparts.

CONCLUSIONS

The uptake of second-generation antidiabetic medications was 14% among patients with T2D in the United States. Prescription benefit design that targets lower out-of-pocket payments for these newer drugs may improve patient access and clinical outcomes for patients with T2D.

Population adjusted-indirect comparisons in health technology assessment: A methodological systematic review

In health technology assessment (HTA), population-adjusted indirect comparisons (PAICs) are increasingly considered to adjust for the difference in the target population between studies. We aim to assess the conduct and reporting of PAICs in recent HTA practice, by performing, a methodological systematic review of studies implementing PAICs from PubMed, EMBASE Classic, Embase/Ovid Medline All, and Cochrane databases from January 1, 2010 to Feb 13, 2023. Four independent researchers screened the titles, abstracts, and full-texts of the identified records, then extracted data on methodological and reporting characteristics of 106 eligible articles. Most PAIC analyses (96.9%, n = 157) were conducted by (or received funding from) pharmaceutical companies. Prior to adjustment, 44.5% of analyses (n = 72) (partially) aligned the eligibility criteria of different studies to enhance the similarity of their target populations. In 37.0% of analyses (n = 60), the clinical and methodological heterogeneity across studies were extensively assessed. In 9.3% of analyses (n = 15), the quality (or bias) of individual studies was evaluated. Among 18 analyses using methods that required an outcome model specification, results of the model fitting procedure were adequately reported in three analyses (16.7%). These findings suggest that the conduct and reporting of PAICs are remarkably heterogeneous and suboptimal in current practice. More recommendations and guidelines on PAICs are thus warranted to enhance the quality of these analyses in the future.

Adverse event reporting of marketed biosimilar and biological monoclonal antibody cancer treatments in the United States

BACKGROUND

By 8 September 2022, 10 biological monoclonal antibody (mAb) biosimilar products for cancer treatment had been approved and marketed in the United States (US). This study examined adverse event (AE) reporting patterns and disproportionate reporting signals for mAb biosimilars in the US compared to their originator biologics.

RESEARCH DESIGN AND METHODS

The US Food and Drug Adverse Event Reporting System database was used to identify AE reports for biological rituximab, bevacizumab, trastuzumab, and their marketed biosimilars. Proportions of patient age, sex and type of reporters of AEs were described for these reports. Reporting odds ratios (RORs) with 95% confidence intervals were calculated to compare reporting disproportionality in serious, death, and specific AEs between mAb biologics/biosimilars (index) and all other drugs. Breslow-Day statistic was used to determine homogeneity in RORs between each mAb biologic-biosimilar pair at p < 0.05.

RESULTS

We observed no risk signals of serious or death AE reporting for all three mAb biosimilars. A signal of disproportionate reporting of death was detected between biological and biosimilar bevacizumab (p < 0.05).

CONCLUSIONS

Our findings support the similarity in signals of disproportionate AE reporting between mAb originator biologics and biosimilars, except for death between biological and biosimilar bevacizumab.

Demographics, clinical disease characteristics, and quality of life in a large cohort of psoriasis patients with and without psoriatic arthritis

Innovation

What is already known about the topic: psoriasis (PsO) is a common skin disease with major impact on quality of life (QoL). Patient-reported data on QoL from large number of PsO patients with and without psoriatic arthritis (PsA) are limited. What this study adds: In a large cohort referred to a university psoriasis center, patients with PsO and concomitant PsA (~30% in this group) had greater degrees of skin and nail involvement and experienced greater negative impacts on QoL. Despite large numbers of patients with moderate-to-severe disease, use of systemic therapy by community practitioners was uncommon.

Background

PsO and PsA are common diseases that have marked adverse impacts on QoL. The disease features and patient-reported QoL data comparing PsO and PsA patients are limited.

Objective

To identify and compare demographics, clinical disease characteristics, and QoL scores in a large cohort of PsO patients with and without PsA.

Methods

All PsO patients seen in a psoriasis specialty clinic, named the Center of Excellence for Psoriasis and Psoriatic Arthritis, were enrolled in an observational cohort. Demographic, QoL, and clinical data were collected from patient-reported questionnaires and from physical examinations performed by Center of Excellence for Psoriasis and Psoriatic Arthritis dermatologists and a rheumatologists. Cross sectional descriptive data were collected and comparisons between patients with PsO alone and those with concomitant PsA are presented.

Results

A total of 568 patients were enrolled in the database. Mean age of PsO onset was 28 years and mean disease duration was 18 years. Those with family history had an earlier onset of PsO by ~7 years. Mean body surface area involvement with PsO was 14%. Mean body mass index was 30.7. Prevalence of PsA was 29.8%. PsA patients had a higher mean body surface area compared to patients with PsO alone (16.7% vs 13.4%, P<0.05), higher prevalence of psoriatic nail changes (54.4% vs 36%, P<0.0002), and worse QoL scores as assessed by the Short Form-12 (67 vs 52, P<0.00001), Psoriasis Quality of Life-12 questionnaire (62 vs 71, P<0.01), and Routine Assessment of Patient Index Data 3 (2.3 vs 4.7, P<0.01). Strikingly, 49% of patients with PsO had never received any systemic therapy.

Conclusion

These data highlight that PsO has marked negative impacts on QoL, while those patients with concomitant PsA are affected to a much greater degree. Despite large numbers of patients presenting with moderate-to-severe disease, use of systemic therapy for both PsO and PsA was uncommon.

A novel, short, and simple screening questionnaire can suggest presence of psoriatic arthritis in psoriasis patients in a dermatology clinic

Delaying diagnosis of psoriatic arthritis (PsA) can lead to poor quality of life and disability. The purpose of this study is to identify simple questions for dermatologists to screen psoriasis patients for psoriatic arthritis. Data regarding psoriasis and arthritis were prospectively collected by a questionnaire from all psoriasis patients. Patients with joint-related symptoms were assessed by a rheumatologist for the presence of PsA. Retrospectively, the sensitivity and specificity, positive and negative predictive values, likelihood ratios, and posttest probabilities of various screening questions were calculated to identify the best combination of parameters. Of 517 patients seen in dermatology clinic, 117 (22.63 %) were found to have PsA. Four screening questions ("Do you have a history of joint pain or swelling?" "Do you have stiffness in the morning?" "Have you had X-rays taken of your joints?" "Do you have PsA?") with psoriatic nail changes demonstrated high sensitivity and specificity for predicting PsA. A cutoff of three out of these five parameters correctly classified patients with and without PsA with 86.9 % sensitivity, 71.3 % specificity, 53 % positive predictive value (PPV), 93.6 % negative predictive value (NPV), and area under the curve (AUC) of 0.87. Likelihood ratios for individual parameters varied between1.6 and 3.7, and with a combination of certain parameters, the posttest probability of PsA was 76 %. This is a preliminary data on a potential screening questionnaire which can help dermatologists quickly screen for PsA. All patients not having evaluated by a rheumatologist could have led to underdiagnosis of PsA and potential misclassification. Psoriasis patients seen at a specialty clinic may introduce a referral bias.

[Influence on flux density of intraoral dental magnets during 1.5 and 3.0 tesla MRI]

PURPOSE

When using dental duo-magnet systems, a mini-magnet remains in the jaw after removal of the prosthesis. In some cases, implant-borne magnets may be removed, whereas tooth-borne magnets are irreversibly fixed on a natural tooth root. The goal of this paper is to identify the impacts of the duration and orientation of exposure on these magnets in a 1.5 or 3 Tesla MRI.

MATERIALS AND METHODS

For this study, 30 SmCo and 60 NdFeB magnets were used. During the first experiment, they were exposed with free orientation for 64 minutes. During the second experiment, the magnets were fixed in position and exposed at 1.5 and 3 Tesla while aligned in a parallel or antiparallel direction.

RESULTS

While the duration of exposure in MRI is irrelevant, the orientation is not. The coercive field strength of these NdFeB and SmCo alloys is not sufficient to reliably withstand demagnetization in a 1.5 or 3 T MRI when aligned in an antiparallel direction. At 1.5 T neodymium magnets were reduced to approx. 34 % and samarium magnets to approx. 92 % of their initial values. At 3 T all magnets were reversed.

CONCLUSION

As a precaution, the worst-case scenario, i. e. an antiparallel orientation, should be assumed when using a duo-magnet system. If an MRI can be postponed, the general dentist should remove implant-borne magnets. If there is a vital indication, irreversible damage to the magnets is acceptable in consultation with the patient since the replacement costs are irrelevant given the underlying disease.

[Signal loss in magnetic resonance imaging caused by intraoral anchored dental magnetic materials]

PURPOSE

To measure the maximum extent of the signal loss areas in the center of the susceptibility artifacts generated by ferromagnetic dental magnet attachments using three different sequences in the 1.5 and 3.0 Tesla MRI.

MATERIALS AND METHODS

Five different pieces of standard dental magnet attachments with volumes of 6.5 to 31.4 mm(3) were used: a NdFeB magnet with an open magnetic field, a NdFeB magnet with a closed magnetic field, a SmCo magnet with an open magnetic field, a stainless steel keeper (AUM-20) and a PdCo piece. The attachments were placed between two cylindrical phantoms and examined in 1.5 and 3.0 Tesla MRI using gradient echo and T1- and T2-weighted spin echoes. We measured the maximum extent of the generated signal loss areas parallel and perpendicular to the direction of B (O).

RESULTS

In gradient echoes the artifacts were substantially larger and symmetrically adjusted around the object. The areas with total signal loss were mushroom-like with a maximum extent of 7.4 to 9.7 cm parallel to the direction of B (O) and 6.7 to 7.4 cm perpendicular to B (O). In spin echoes the signal loss areas were obviously smaller, but not centered. The maximum values ranged between 4.9 and 7.2 cm (parallel B (O)) and 3.6 and 7.0 cm (perpendicular B (O)). The different ferromagnetic attachments had no clinically relevant influence on the signal loss neither in 1.5 T nor 3.0 T MRI.

CONCLUSIONS

Ferromagnetic materials used in dentistry are not intraorally standardized. To ensure, that the area of interest is not affected by the described artifacts, the maximum extent of the signal loss area should be assumed: a radius of up to 7 cm in 1.5 and 3.0 T MRI by T1 and T2 sequences, and a radius of up to 10 cm in T2* sequences. To decide whether magnet attachments have to be removed before MR imaging, physicians should consider both the intact retention of the keepers and the safety distance between the ferromagnetic objects and the area of interest.

Mechanisms of serum potentiation of GM-CSF production by human airway smooth muscle cells

Inflammation and vascular leakage are prevalent in asthma. This study aimed to elucidate the mechanisms involved in serum potentiation of cytokine-induced granulocyte macrophage colony stimulating factor (GM-CSF) production by human airway smooth muscle cells and to identify possible factors responsible. Serum-deprived cells at low density were stimulated with TNF-alpha and IL-1beta for 24 h. Human AB serum (10%), inhibitors of RNA and protein synthesis or specific signaling molecules, or known smooth muscle mitogens were then added for 24 h. Culture supernatants were analyzed for GM-CSF levels, and cells were harvested to assess viability, cell cycle progression, GM-CSF-specific mRNA content, and p38 phosphorylation. Serum potentiated GM-CSF release when added before, together with (maximal), or after the cytokines. The potentiation involved both new GM-CSF-specific mRNA production and protein synthesis. The mitogens IGF, PDGF, and thrombin all potentiated GM-CSF release, and neutralizing antibodies for EGF, IGF, and PDGF reduced the serum potentiation. Inhibitor studies ruled as unlikely the involvement of p70(S6kinase) and the MAPK p42/p44, two signaling pathways implicated in proliferation, and the involvement of the MAPK JNK, while establishing roles for p38 MAPK and NF-kappaB in the potentiation of GM-CSF release. Detection of significant p38 phosphorylation in response to serum stimulation, through Western blotting, further demonstrated the involvement of p38. These studies have provided evidence to support p38 being targeted to interrupt the cycle of inflammation, vascular leakage and cytokine production in asthma.

Training and supporting GPs in providing palliative care to a Vietnamese-Australian community

The mooted increasing role for general practitioners to provide palliative care for an aging Australian population has raised the need for improved training and support for GPs to provide 'healthcare for dying people that maximizes quality of life and assists families and carers during and after death'. In order to address this need, the Commonwealth Department of Health and Ageing commissioned a study into the education, training and support needs of GPs in palliative care. This article reports one element of this national study: the needs of GPs who provide palliative care to a Vietnamese-Australian community in Sydney, New South Wales.

Cell division genes promote asymmetric interaction between Numb and Notch in the Drosophila CNS

Cell intrinsic and cell extrinsic factors mediate asymmetric cell divisions during neurogenesis in the Drosophila embryo. In the NB4-2-&gt;GMC-1-&gt;RP2/sib lineage, one of the well-studied neuronal lineages in the ventral nerve cord, the Notch (N) signaling interacts with the asymmetrically localized Numb (Nb) to specify sibling neuronal fates to daughter cells of GMC-1. In this current study, we have investigated asymmetric cell fate specifications by N and Nb in the context of cell cycle. We have used loss-of-function mutations in N and nb, cell division mutants cyclinA (cycA), regulator of cyclin A1 (rca1) and string/cdc25 phosphatase (stg), and the microtubule destabilizing agent, nocodazole, to investigate this issue. We report that the loss of cycA, rca1 or stg leads to a block in the division of GMC-1, however, this GMC-1 exclusively adopts an RP2 identity. While the loss of N leads to the specification of RP2 fates to both progeny of GMC-1 and loss of nb results in the specification of sib fates to these daughter cells, the GMC-1 in the double mutant between nb and cycA assumes a sib fate. These epistasis results indicate that both N and nb function downstream of cell division genes and that progression through cell cycle is required for the asymmetric localization of Nb. In the absence of entry to metaphase, the Nb protein prevents the N signaling from specifying sib fate to the RP2/sib precursor. These results are also consistent with our finding that the sib cell is specified as RP2 in N; nb double mutants. Finally, our results show that nocodazole-arrested GMC-1 in wild-type embryos randomly assumes either an RP2 fate or a sib fate. This suggests that microtubules are involved in mediating the antagonistic interaction between Nb and N during RP2 and sib fate specification.

Angiographic anatomy of the coronary sinus and its tributaries

Permanent left ventricular pacing has been shown to improve the hemodynamic and clinical status of patients with severe heart failure. To pace the left ventricle, the electrode is implanted in tributaries of the coronary sinus (CS). However, the anatomy of cardiac veins with this purpose in mind has not been described in detail.

METHODS

One hundred consecutive patients admitted for coronary angiography had a simultaneous coronary venography performed after the injection of 8 to 10 mL of contrast material into the left coronary artery. Cardiac veins were analyzed in antero-posterior, left anterior oblique 60 degrees, and right anterior oblique 30 degrees views by three different observers. The number, dimension, angulation, and position of the coronary sinus and of its tributaries were studied.

RESULTS

Two veins are consistently present: the middle cardiac vein (mean diameter 2.62 +/- 1.26 mm) and the great cardiac vein (mean diameter 3.55 +/- 1.24 mm). The left posterior vein(s) (LPV) (mean diameter 2.25 +/- 1.2 mm) is (are) variable in number (ranging from 0 to 3), size, and angulation. The absence of LPV limits the ability to pace the left ventricle endovenously. The diameter of the vein (< 2 mm) and its angulation may also complicate the insertion of the lead.

CONCLUSION

Angiographic analysis of dimensions, tortuosity, number, and angulation of venous tributaries of the CS seems to allow the insertion of commercially available pacing leads in approximately 85% of cases. An increase in this percentage hinges on the development of new, dedicated leads.

Tissue-type plasminogen activator is a target of the tumor suppressor gene maspin

The maspin protein has tumor suppressor activity in breast and prostate cancers. It inhibits cell motility and invasion in vitro and tumor growth and metastasis in nude mice. Maspin is structurally a member of the serpin (serine protease inhibitors) superfamily but deviates somewhat from classical serpins. We find that single-chain tissue plasminogen activator (sctPA) specifically interacts with the maspin reactive site loop peptide and forms a stable complex with recombinant maspin [rMaspin(i)]. Major effects of rMaspin(i) are observed on plasminogen activation by sctPA. First, rMaspin(i) activates free sctPA. Second, it inhibits sctPA preactivated by poly-D-lysine. Third, rMaspin(i) exerts a biphasic effect on the activity of sctPA preactivated by fibrinogen/gelatin, acting as a competitive inhibitor at low concentrations (< 0.5 microM) and as a stimulator at higher concentrations. Fourth, 38-kDa C-terminal truncated rMaspin(i) further stimulates fibrinogen/gelatin-associated sctPA. rMaspin(i) acts specifically; it does not inhibit urokinase-type plasminogen activator, plasmin, chymotrypsin, trypsin, or elastase. Our kinetic data are quantitatively consistent with a model in which two segregated domains of maspin interact with the catalytic and activating domains of sctPA. These complex interactions between maspin and sctPA in vitro suggest a mechanism by which maspin regulates plasminogen activation by sctPA bound to the epithelial cell surface.

Primary adrenal lymphoma: gallium scintigraphy and correlative imaging

Primary adrenal lymphoma is a rare entity, with only 16 cases reported in the last 40 yr. Although 67Ga scintigraphy has been extensively used to evaluate patients with other types of lymphomas, there are no reports of its use in patients with this disease entity. A man with primary adrenal lymphoma and no evidence of extraadrenal spread who was evaluated from presentation to remission with gallium scintigraphy and CT is presented. Gallium scintigraphy was valuable in assessing response to therapy.