Efficacy and safety of antiplatelet therapy in COVID-19: Insights from a meta-analysis of randomized controlled trials

BACKGROUND

COVID-19 induces a pro-coagulant state with thrombotic events. This meta-analysis explores the efficacy and safety of antiplatelet-based therapy in COVID-19 patients through randomized controlled trials (RCTs).

MATERIALS AND METHODS

A systematic literature search until March 10, 2023, identified 7 RCTs involving 23,415 inpatients. Of these, 11,891 received antiplatelet-based treatment, and 11,524 received placebo/other drugs. Statistical analysis was performed using Review Manager 5.4.

RESULTS

The included trials involved patients with a mean age ranging from 54.3 to 62.0 years and a prevalence of hypertension ranging from 10.9 to 65.0% and coronary artery disease ranging from 3.2 to 32.7%. The pooled analysis showed no significant difference in overall mortality between groups (RR 1.0, 95% CI 0.99 - 1.01, p = 0.76). However, antiplatelet therapy significantly reduced major thrombotic events (RR 0.86, 95% CI 0.75 - 0.99, p = 0.04). Conversely, it increased major bleeding risks (RR 1.62, 95% CI 1.24 - 2.12, p = 0.0005). There was no significant difference in the incidence of invasive mechanical ventilation and respiratory death.

CONCLUSION

Antiplatelet therapy does not confer mortality benefit in COVID-19 patients but lowers major thrombotic events while increasing major bleeding risks. Ongoing large RCTs will provide more information on the therapeutic value of this therapy.

miR-1268a Regulates Fatty Acid Metabolism by Targeting CD36 in Angiotensin II-induced Heart Failure

Multiple RNAs have been involved in the progress of heart failure. However, the role of miR-1268a in heart failure is still unclear. The differentially expressed miRNAs in heart failure was analyzed based on GEO dataset GSE104150. AC16 cells were treated with Angiotensin II (Ang II) to explore the role of miR-1268a in heart failure. The web tool miRWalk was used to analyze the targets of miR-1268a. miR-1268a was up-regulated in Ang II-treated AC16 cells. Ang II treatment markedly inhibited cell proliferation, ATP production, fatty acid (FA) uptake and enhanced levels of HF markers BNP and ST2, and oxidative stress of AC16 cells. Notably, inhibition of miR-1268a eliminated the inhibiting effect of Ang II on cell proliferation, ATP production, FA uptake and decreased levels of BNP an ST2, and oxidative stress on AC16 cells. Furthermore, CD36 was a target of miR-1268a and the CD36 level was decreased by miR-1268a mimics but increased by miR-1268a inhibitor in AC16 cells. miR-1268a regulates FA metabolism and oxidative stress in myocardial cells by targeting CD36 in heart failure.

A meta-analysis of randomized controlled trials of statin-based therapy in patients with COVID-19

BACKGROUND

Previous observational studies and meta-analyses have suggested that statins could be beneficial in reducing the risk of adverse clinical outcomes. This study is the first to conduct a meta-analysis of recently published randomized controlled clinical trials investigating the potential therapeutic benefits of statins for COVID-19.

MATERIALS AND METHODS

A thorough search was conducted using databases such as PubMed and Embase until May 2023 to identify randomized controlled clinical trials investigating the use of statins in patients with COVID-19. Review Manager 5.4 was used to analyze the selected studies.

RESULTS

Seven randomized controlled trials comprising a total of 2,370 patients were included in this study. Of these, 1,295 patients received statin therapy, while 1,075 received placebo or other drugs. All included studies were conducted on inpatients with an average age of 45 - 61 years, and the proportion of patients with diabetes and coronary heart disease was less than 30%. One study only included severely ill patients. Our results showed that statin treatment did not significantly reduce hospitalized patient mortality (11.5 vs. 13.4%, p = 0.94), the proportion of patients transferred to intensive care due to disease changes (14.2 vs. 11.2%, p = 0.41), or the proportion of patients requiring mechanical ventilation (5.3 vs. 7.9%, p = 0.71) compared to controls. However, the use of statins was associated with a slight increase in hospital stay.

CONCLUSION

A critical appraisal of published randomized controlled trials on statin therapy in COVID-19 did not show any significant effect on mortality, the risk of transfer to intensive care, or mechanical ventilation.

MicroRNA‑126 and VEGF enhance the function of endothelial progenitor cells in acute myocardial infarction

Previous studies have found that microRNA-126 (miR-126) overexpression can exert beneficial effects on endothelial function and angiogenesis. The role of miR-126 was previously reported to be by directly limiting the activities of negative regulators of the vascular endothelial growth factor (VEGF) pathway, such as PI3K regulation subunit 2 (PIK3R2). The aim of the present study was to investigate the role of the miR-126/PIK3R2/VEGF axis in endothelial progenitor cells (EPCs) under hypoxic conditions. An in vitro hypoxia model in EPCs was established by exposing EPCs to hypoxia (O²/N²/CO², 1/94/5) for 72 h, before reverse transcription-quantitative PCR (RT-qPCR) and western blot analyzes were used to measure miR-126 and PIK3R2 expression in EPCs. The proliferation, migration and tube-forming ability of the transfected cells were measured using MTT, Transwell and tube formation assays, respectively. miR-126 expression was found to be lower in EPCs in the hypoxia group compared with that in the control group (P<0.01). The expression of PIK3R2, a direct target gene of miR-126, was found to be higher in the hypoxia group compared with that in the control group (P<0.01). miR-126 mimic and VEGF-plasmid co-transfection improved the proliferation, migration, tube-forming ability and restored the phosphorylation of AKT in EPCs under hypoxic conditions (all P<0.01). In addition, the effects of miR-126 mimic on hypoxia-induced EPCs were reversed by PIK3R2-plasmid co-transfection, whilst the effects of VEGF-plasmid were enhanced further by co-transfection with the miR-126 mimic. In conclusion, miR-126 promoted the functions of EPCs under hypoxic conditions by negatively targeting PIK3R2, whilst the combined overexpression of miR-126 and VEGF enhanced these aforementioned effects.

Hypoxia-inducible transcription factor-1α inhibition by topotecan protects against lipopolysaccharide-induced inflammation and apoptosis of cardiomyocytes

Background

Myocarditis, an inflammatory disease of the myocardium, is a serious hazard to human life due to the expansion of inflammatory lesions in the myocardium. The aim of this study was to investigate the role of hypoxia-inducible transcription factor (HIF)-1α and its inhibitor topotecan in the pathogenesis of myocarditis.

Methods

H9c2 cardiomyoblasts was stimulated with lipopolysaccharide (LPS) to simulate myocarditis model in vitro. The levels of myocardial damage markers were determined using commercially available kits. Western blotting was used to evaluate HIF-1α expression after LPS challenge. Then, after HIF-1α silencing, the contents of inflammatory factors were determined with enzyme-linked immunosorbent assay (ELISA). Cell viability was tested by means of a cell counting kit-8 (CCK-8) assay. Cell apoptosis was assessed by flow cytometry, and the expression of apoptotic proteins was examined using western blot analysis. Subsequently, HIF-1α was overexpressed and topotecan was employed to treat H9c2 cells under LPS exposure condition. The biological functions were detected again.

Results

LPS significantly elevated the levels of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) and cardiac troponin-I (cTn-I) in supernatant of H9c2 cell lysates. Additionally, LPS led to the notably upregulated expression of HIF-1α. HIF-1α-knockdown markedly decreased the concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8 compared with the LPS-induced group. Moreover, the cell viability was conspicuously enhanced and cell apoptotic ratio was remarkably reduced, accompanied by downregulated expression of Bax, Bim, caspase 3 and caspase 9 after HIF-1α silencing. Consistently, HIF-1α gain-of-function significantly promoted the production of inflammatory cytokines and cell apoptosis, which was partially counteracted by topotecan administration.

Conclusion

To conclude, these findings demonstrated that HIF-1α inhibition by topotecan ameliorates LPS-induced myocarditis in vitro, providing a new approach in the treatment of myocarditis.

A case of hypersensitivity to progesterone presenting as an eczematous eruption

Hypersensitivity to progesterone is a rare condition, and it represents a hypersensitivity reaction to endogenous progesterone. Here we report a case of a woman who presented to our attention for evaluation of a rash for a few years on her posterior elbows, forearms, and right lateral lower extremity. We report this case because it describes a rare clinical entity, with an atypical clinical presentation pemphigoid-like, that is rarely described in literature.

Angiotensin-(1-7) attenuates angiotensin II-induced signalling associated with activation of a tyrosine phosphatase in Sprague-Dawley rats cardiac fibroblasts

BACKGROUND INFORMATION

Angiotensin-(1-7) [ANG-(1-7)] mediates vasodilation, antiproliferation, anti-apoptosis and antifibrosis, therefore, it opposes the effects of angiotensin II (ANG II). However, the detailed signal transduction mechanism following the Mas receptor activated by ANG-(1-7) is still poorly understood. Src homology2-containing inositol phosphatase 1 (SHP-1), a redoxsensitive protein tyrosine phosphatase, negatively influences downstream signalling molecules, such as mitogen-activated protein kinases (MAPKs), through dephosphorylation, thereby inhibiting proliferative and profibrotic signalling induced by ANG II. Therefore, we hypothesised that SHP-1 may mediate the antiproliferative signalling of ANG-(1-7) through the regulation of the dynamic balance of MAPKs and SHP-1 in isolated cardiac fibroblasts. Primary culture of neonatal Sprague-Dawley rats cardiac fibroblasts was treated separately with different interventions to investigate this issue.

RESULTS

Our data revealed that ANG II increased the phosphorylation of extracellular signal-related kinase (p-ERK1/2) and the ratio of (p-ERK1/2)/(ERK1/2), but ANG-(1-7) decreased them. The effects of ANG-(1-7) on the phosphorylation p-ERK1/2 were blocked by the Mas receptor antagonist A-779. Unlike ANG II, which decreased the activity of SHP-1, ANG-(1-7) increased its activity. Overexpression of SHP-1 attenuated the ANG II-stimulated phosphorylation of c-Src, its downstream molecules ERK1/2, α-smooth muscle actin and transforming growth factor-β1 (TGF-β1). These effects were also inhibited by the specific inhibitor of SHP-1, sodium stibogluconate. ANG-(1-7) had no significant effects on the gene expression of TGF-β1, collagen I or collagen III, but was found to antagonise the stimulatory effects of ANG II on them.

CONCLUSIONS

ANG-(1-7), through Mas receptor, activates SHP-1 in cardiac fibroblasts, which can negatively modulate ANG II-induced phosphorylation of c-Src and MAPKs, and inhibits profibrotic factors TGF-β1 and collagen production. ANG-(1-7) can thereby serve as a protective role by counteracting the effects of ANG II.

Nephrogenic systemic fibrosis with a spectrum of clinical and histopathological presentation: a disorder of aberrant dermal remodeling

BACKGROUND

Nephrogenic fibrosing dermopathy (NFD) has emerged as a clinicopathologic entity since 1997 and recently renamed as nephrogenic systemic fibrosis (NSF). The etiology and pathogenesis remain uncertain. Characteristic clinical presentation is described as diffuse thickening and hardening of the skin occurring in patients with renal insufficiency. Typical histological features include proliferation of CD34 positive fibrocytes, increased thick collagen bundles and mucin deposition, without significant inflammatory infiltrate. Variations in clinical presentations have been reported, including papular and plaque-like skin lesions, focal lesion only, as well as systemic involvement. Histological changes can be subtle and non-specific, overlapping with other disease processes and harboring features including calcification and osteoclast-like giant cells with osseous metaplasia.

METHODS

We reviewed patients with NSF that presented to our dermatology clinic by chart review, clinical examination and histological examination. Skin biopsy specimens were obtained from all cases. Histopathology evaluations were carried out by three dermatopathologists (AD, BS and GK) independently and the features were compared among all the cases. Special stains and immunohistochemistry study were also performed to highlight the histological features.

RESULTS

Seven cases of NSF presented with a spectrum of clinical manifestations, from classic diffuse hardening of the skin to localized linear plaques. On histological examination, proliferation of CD34-positive fibrocytes ranged from sparse to dense, collagen bundles ranged from thin to thick, and the interstitial dermal mucin accumulation ranged from scant-patchy to abundant. In addition, the lesion displayed various degrees of vascular proliferation, inflammatory infiltrates and intensities of CD68 and Factor XIIIa staining. Two cases showed extensive dermal calcification and ossification.

CONCLUSION

NSF may present with a spectrum of clinical abnormalities, and exhibit overlapping histopathological features resembling cicatrix and other dermal reparative/regenerative processes. NSF may in fact to be a disorder of aberrant extracellular matrix remodeling in patients with renal insufficiency.

Peptide-mediated Gene Transfer of Cationic Lipid/Plasmid DNA Complexes to Endothelial Cells

The purpose of this research is to develop ligand-targeted plasmid based gene delivery systems for gene transfer to tumor endothelium. Cell adhesion assays were used to test the peptide inhibition of human endothelial cell adsorption to vitronectin-treated tissue culture plates. A series of RGD containing peptides were tested in linear form and with one and two disulfide bonds. The linear and two disulfide bond peptides yielded similar IC50 (approximately 1 x 10(-7) M). Substitution of two methionines for cysteines yielded a single disulfide bond that increased the IC50 by 10-fold. The single and double disulfide peptides were derivatized to N-succinyl-dioleoylphopsphatidylethanolamine and incorporated into 100 nm liposomes radiolabeled with H-cholesterylhexadecylether. Liposome uptake by human umbilical vein endothelial cells was tested as a function of lipopeptide surface density. Increase in membrane surface density from 5 to 20mol% increased human umbilical derived endothelial cell (HUVEC) uptake of the liposomes for both the single and double disulfide peptides. Liposome uptake by HUVECs was 3-fold greater for the double disulfide compared to the single disulfide. The single and double disulfide lipopeptides were then tested for gene transfer to HUVECs using DOTMA:Cholesterol cationic liposomes. The polyplexes were formed by rapidly mixing plasmid DNA with DOTMA:CHOL liposomes at a 3:1 charge ratio in 2% ethanol, 10% lactose. The ethanol was removed by lyophilization and upon rehydration, the lipoplexes had a mean diameter of approximately 100nm. HUVEC transfection studies showed that increasing the mol% of the single disulfide RGD lipopeptide to 20mol% increased gene transfer by 10-fold. This increase in transfection could be reduced to that obtained in the absence of lipopeptide by co-incubating the HUVECs with a 100-fold excess of the single disulfide RGD peptide, thus demonstrating lipopeptide mediated gene transfer to endothelial cells.

Preinfusion variables predict the predominant unit in the setting of reduced-intensity double cord blood transplantation

Double cord blood transplantation (DCBT) may overcome the slow hematopoietic recovery and engraftment failure associated with infusion of a single cord blood unit. In DCBT, only one unit typically contributes to long-term hematopoiesis, but little is known about factors affecting cord predominance. As results from a phase I trial suggested that order of infusion may affect cord predominance, we analyzed the effect of preinfusion variables on chimerism patterns of 38 patients enrolled in the initial study and a subsequent phase II trial. All patients were treated with a reduced-intensity conditioning (RIC) regimen of fludarabine, melphalan and thymoglobulin followed by DCBT. By day 100, 66% of patients had hematopoiesis derived from a single cord blood unit. Higher post-thaw total nucleated cell and CD34+ cell dose were associated with cord predominance and in 68% of patients (P=0.03); the predominant cord blood unit was infused first. Only the post-thaw CD34+ cell dose of the predominant unit predicted time to both neutrophil and platelet engraftment. Although based on a small number of patients, our results identify parameters that may affect cord predominance and engraftment in the setting of DCBT following RIC and suggest possible strategies for selecting infusion order for cord blood units.

CD34(+) CD38(-) and CD34(+) HLA-DR(-) cells in BM stem cell grafts correlate with short-term engraftment but have no influence on long-term hematopoietic reconstitution after autologous transplantation

BACKGROUND

Prior studies have demonstrated that relatively immature hematopoietic stem cells, including CD34(+) CD38(-) and CD34(+) HLA-DR(-) subsets, correlate with short-term hematopoietic reconstruction (SHR) after transplantation. The aim of this study was to investigate whether these immature CD34(+) subsets also correlate with long-term hematopoietic reconstitution (LHR) in recipients of ABMT.

METHODS

We examined stem cell grafts from 58 patients with B-cell lymphoma or CLL who underwent ABMT after myeloablative conditioning. We determined whether total mononuclear cell dose (MNC), colony-forming unit-granulocyte-monocyte (CFU-GM), CD34(+) cell dose and CD34(+) cell subsets (CD34(+) CD38(-) and CD34(+) HLA-DR(-) were associated with SHR and/or LHR. Time to neutrophil engraftment (TNE) and time to platelet engraftment (TPE) were used to measure SHR, while platelet counts at day 100 and 1 year post-ABMT were used as indicators for LHR.

RESULTS AND DISCUSSION

CD34(+) cell dose and CD34(+) cell subsets were significantly associated with SHR. However, at day 100 and 1 year post-transplant only total CD34(+) cell dose was associated with LHR. The association of total CD34(+) cell dose with LHR persisted after adjusting for age, sex and disease. None of the CD34(+) cell subsets analyzed showed evidence of significant association with LHR.

Partial CD8+ T-cell depletion of allogeneic peripheral blood stem cell transplantation is insufficient to prevent graft-versus-host disease

Prior studies suggest that depletion of CD8+ T cells from donor bone marrow or donor lymphocyte infusions can reduce graft-versus-host disease (GVHD) without compromising graft-versus-leukemia. We explored CD8 depletion in patients undergoing matched related donor (MRD, n=25) and unrelated donor (URD, n=16) peripheral blood stem cell transplantation following myeloablative conditioning with cyclophosphamide (60 mg/kg/day i.v. x 2) and total body irradiation (200 cGy x 7 fractions). Ex vivo incubation of mobilized donor peripheral blood cells with anti-CD8 antibody coated high-density microparticles removed 99% of CD8+ cells. The median number of CD8+ cells infused was 3.9 x 10(5) cells/kg (2.2 x 10(5) in MRD, and 8.1 x 10(5) in URD patients). Post transplant immune suppression included tacrolimus in the MRD cohort, and tacrolimus plus mini-methotrexate (5 mg/m2 days +1, 3, 6, 11) in the URD cohort. All 41 patients engrafted. Grade 2-4 acute GVHD incidence was 61% (44% MRD, 88% URD). Chronic GVHD incidence was 50% (48% MRD, 55% URD). Relapse incidence was 4.9%. Estimated event-free and overall survival rates were 65 and 63%, respectively, at 1 year and 56 and 57%, respectively, at 2 years. There was no correlation between CD8+ number and GVHD or survival. A 2-log depletion of CD8+ cells from PBSC is insufficient to prevent GVHD.

Apoptosis: an early event in metastatic inefficiency

Whereas large numbers of cells from a primary tumor may gain access to the circulation, few of them will give rise to metastases. The mechanism of elimination of these tumor cells, often termed "metastatic inefficiency," is poorly understood. In this study, we show that apoptosis in the lungs within 1-2 days of introduction of the cells is an important component of metastatic inefficiency. First, we show that death of transformed, metastatic rat embryo cells occurred via apoptosis in the lungs 24-48 h after injection into the circulation. Second, we show that Bcl-2 overexpression in these cells inhibited apoptosis in culture and also conferred resistance to apoptosis in vivo in the lungs 24-48 h after injection. This inhibition of apoptosis led to significantly more macroscopic metastases. Third, comparison between the extent of apoptosis by a poorly metastatic cell line to that by a highly metastatic cell line 24 h after injection in the lungs revealed more apoptosis by the poorly metastatic cell line. These results indicate that apoptosis, which occurs at 24-48 h after hematogenous dissemination in the lungs is an important determinant of metastatic inefficiency. Although prior work has shown an association between apoptosis in culture and metastasis in vivo, this work shows that apoptosis in vivo corresponds to decreased metastasis in vivo.

Ultrasound enhancement of cationic lipid-mediated gene transfer to primary tumors following systemic administration

The impact of a localized application of ultrasound on gene transfer to primary tumors following systemic administration of cationic lipid based transfection complexes was investigated. We have previously shown that systemic administration of DOTMA (N-[(1-(2-3-dioleyloxy) propyl)]-N-N-N-trimethylammonium chloride):cholesterol-based transfection complexes to tumor-bearing mice resulted in expression in the tumor and other tissues, primarily the lungs. Application of ultrasound to the tumor before or after the injection resulted in a significant increase in gene transfer to the tumor with no increase observed in other tissues. The magnitude of increased expression ranged from three- to 270-fold depending upon the DNA dose. The following parameters were optimized for maximal increase: duration of ultrasound application, the time interval between plasmid injection and sonoporation, and plasmid dose. A combination of plasmid quantitation and fluorescence microscopy showed that ultrasound increased tumor uptake of the plasmid and that uptake was limited to the tumor vasculature. Using an IL- 12 expression plasmid, the combination of a single plasmid dose (10 microg) and ultrasound treatment produced significantly higher levels of IL-12 in tumor. This increased expression was sufficient to inhibit tumor growth compared with the control conditions. These data demonstrate the potential application of sonoporation as an effective method for enhancing the expression of systemically administered genes in tumor endothelium for cancer gene therapy.

Optimization of cationic lipid/DNA complexes for systemic gene transfer to tumor lesions

Intravenous (i.v.) administration of cationic lipid N-[( 1-(2-3-dioleyloxy)propyl)]-N-N-N-trimethylammonium chloride (DOTMA)-based transfection complexes in mice with subcutaneous squamous cell tumors yielded plasmid delivery and expression in tumor lesions. The efficiency of gene transfer in tumors was significantly lower than in the lung. This was consistent with low plasmid levels associated with the tumor, suggesting that plasmid delivery to the tumor site was a limiting factor. Lowering the lipid/DNA charge ratio from 5:1 to 0.8:1 (+/-) did not change DNA levels in tumor but significantly reduced DNA levels in lung. However, expression levels were significantly reduced in both tissues at lower lipid/DNA charge ratios. Complexes prepared from small unilamellar liposomes gave significantly lower expression levels in the lungs but similar expression levels in tumors when compared to complexes prepared from larger unilamellar liposomes. The small liposome complexes were better tolerated than large liposome complexes. Varying the cationic lipid to colipid (cholesterol or DOPE) molar ratio from 4: 1 to 1: 1 significantly reduced expression levels in both tumor and lung. Cationic lipid substitution, using a cholesterol cationic lipid, diethyldiamino-carbamyl-cholesterol instead of DOTMA, produced reduced expression in all other tissues except tumor. Incorporation of PEG into preformed transfection complexes reduced DNA delivery to lung, increased circulation half-life, and enhanced DNA delivery to tumor. In a lung metastatic mouse tumor model, where the accessibility of the i.v. administered transfection complexes to tumor lesions should be less challenging, DOTMA: CHOL complexes (4: 1 lipid to colipid molar ratio, 3: 1 +/- lipid to plasmid charge ratio) were preferentially localized in tumor lesions. These data demonstrate that systemic gene transfer to distal tumor sites by lipid/ DNA complexes may be limited by low plasmid delivery. Modifying the chemical surface properties of transfection complexes enhanced both DNA delivery and expression in tumor and is one approach that may overcome limitations.

Cationic lipid-based delivery system for systemic cancer gene therapy

A cationic lipid-based gene delivery system composed of N-[(1-(2,3-dioleyloxy)propyl)]-N-N-N-trimethylammonium chloride and cholesterol, at a 4:1 molar ratio, was developed for systemic administration. Plasmid biodistribution and expression were characterized in syngeneic mouse tumor model squamous cell carcinoma VII cells. A reporter gene expression plasmid was used for biodistribution of plasmid and expression. The results showed that lungs and primary tumors were transfected. Fluorescence microscopy showed that fluorescent-labeled transfection complexes were passively targeted to the tumor vasculature and that the endothelial cells internalized the plasmid. Transgene expression was characterized based on duration of expression and dosing schedule. In vivo gene transfer with an interleukin-12 expression plasmid yielded protein levels in blood, lungs, and primary tumor after intravenous administration. Efficacy studies showed that 15 microg of interleukin-12 plasmid was sufficient to produce a gene-specific inhibition of primary tumor growth. These results characterize the vascularity of the tumor model, characterize the in vivo gene transfer properties of the plasmid-based gene delivery system, and show that the transgene expression level was sufficient to elicit a biological response by inhibiting tumor growth.

Rationally designed anti-HER2/neu peptide mimetic disables P185HER2/neu tyrosine kinases in vitro and in vivo

Monoclonal antibodies specific for the p185HER2/neu growth factor receptor represent a significant advance in receptor-based therapy for p185HER2/neu-expressing human cancers. We have used a structure-based approach to develop a small (1.5 kDa) exocyclic anti-HER2/neu peptide mimic (AHNP) functionally similar to an anti-p185HER2/neu monoclonal antibody, 4D5 (Herceptin). The AHNP mimetic specifically binds to p185HER2/neu with high affinity (KD=300 nM). This results in inhibition of proliferation of p185HER2/neu-overexpressing tumor cells, and inhibition of colony formation in vitro and growth of p185HER2/neu-expressing tumors in athymic mice. In addition, the mimetic sensitizes the tumor cells to apoptosis when used in conjunction with ionizing radiation or chemotherapeutic agents. A comparison of the molar quantities of the Herceptin antibody and the AHNP mimetic required for inhibiting cell growth and anchorage-independent growth showed generally similar activities. The structure-based derivation of the AHNP represents a novel strategy for the design of receptor-specific tumor therapies.

Induction of the TRAIL receptor KILLER/DR5 in p53-dependent apoptosis but not growth arrest

The TRAIL death receptor KILLER/DR5 is induced by DNA damaging agents in wild-type p53-expressing cells. Here we show that, unlike the p53-target CDK-inhibitor p21WAF1/CIP1, the TRAIL death receptor KILLER/DR5 is only induced in cells undergoing p53-dependent apoptosis and not cell cycle arrest. Thus GM glioblastoma cells carrying an inducible MMTV-driven p53 gene undergo cell cycle arrest and upregulate p21 but not KILLER/DR5 expression upon dexamethasone exposure. WI38 normal lung fibroblasts undergoing cell cycle arrest in response to ionizing irradiation also induce p21 but not KILLER/DR5 gene expression. KILLER/DR5 upregulation is also deficient in irradiated lymphoblastoid cells derived from patients with Ataxia Teleangiectasia suggesting a role for the ATM-p53 pathway in regulating KILLER/DR5 expression after DNA damage. Inhibition of transcription by Actinomycin D blocks both KILLER/DR5 and p21 induction in cells undergoing p53-dependent apoptosis. Our results suggest that the p53-dependent transcriptional induction of KILLER/DR5 death receptor is restricted to cells undergoing apoptosis and not cells undergoing exclusively p53-dependent G1 arrest.

Netrin UNC-6 and the regulation of branching and extension of motoneuron axons from the ventral nerve cord of Caenorhabditis elegans

In the Caenorhabditis elegans embryo, some ventral midline motoneurons extend a process circumferentially to the dorsal midline and a process longitudinally along ventral nerve cord interneurons. Circumferential migrations are guided by netrin UNC-6, which repels motoneuron axons dorsally. Although the motoneuron cell bodies and the longitudinal axons are positioned along UNC-6-expressing interneurons in the ventral nerve cord, the circumferential processes extend only from the motoneuron cell bodies and from defined locations along some longitudinal axons. This implies a mechanism regulates motoneuron branching of UNC-6-responsive processes. We show that expression of unc-6DeltaC, which encodes UNC-6 without domain C, partially rescues circumferential migration defects in unc-6 null animals. This activity depends on the netrin receptors UNC-5 and UNC-40. These results indicate that UNC-6DeltaC can provide the circumferential guidance functions of UNC-6. Furthermore, we show that expression of unc-6DeltaC causes motoneuron branching and the extension of processes from abnormal positions along the ventral nerve cord. This activity is also UNC-5- and UNC-40-dependent. We propose that local interactions mediated by domain C regulate motoneuron branching and responsiveness to the UNC-6 cue.

Disseminated cutaneous protothecosis in an immunocompromised host: a case report and literature review

Protothecosis is an infection caused by achloric algae of the genus Prototheca. These organisms have been isolated from water, sewage, soil, and the slime flux of trees, and are a known cause of disease in other mammals. Infection in humans occurs after traumatic inoculation, producing localized olecranon bursal or, rarely, systemic disease. Only two previous cases of disseminated cutaneous disease have been reported in patients with defective neutrophil function. We describe a rare case of widespread cutaneous dissemination occurring after an arthropod bite in an immunocompromised patient.

The G2 block induced by DNA damage: a caffeine-resistant component independent of Cdc25C, MPM-2 phosphorylation, and H1 kinase activity

Treatment of cells with agents that cause DNA damage often results in a delay in G2. There is convincing evidence showing that inhibition of p34cdc2 kinase activation is involved in the DNA damage-induced G2 delay. In this study, we have demonstrated the existence of an additional pathway, independent of the p34cdc2 kinase activation pathway, that leads to a G2 arrest in etoposide-treated cells. Both the X-ray-induced and the etoposide-induced G2 arrest were associated with inhibition of the p34cdc2 H1 kinase activation pathway as judged by p34cdc2 H1 kinase activity and phosphorylation of cdc25C. Caffeine treatment restored these activities after either of the treatments. However, the etoposide-treated cells did not resume cycling, revealing the presence of an alternative pathway leading to a G2 arrest. To explore the possibility that this additional pathway involved phosphorylation of the MPM-2 epitope that is shared by a large family of mitotic phosphoproteins, we monitored the phosphorylation status of the MPM-2 epitope after DNA damage and after treatment with caffeine. Phosphorylation of the MPM-2 epitope was depressed in both X-ray and etoposide-treated cells, and the depression was reversed by caffeine in both cases. The results indicate that the pathway affecting MPM-2 epitope phosphorylation is involved in the G2 delay caused by DNA damage. However, it is not part of the caffeine-insensitive pathway leading to a G2 block seen in etoposide-treated cells.

Experimental testing of a DEXA-derived curved beam model of the proximal femur

This study was designed to test whether, using curved beam theory, a structural model of the proximal femur derived from two-dimensional dual energy x-ray absorptiometry could be used to predict femoral strength in an experimental simulation of a fall on the greater trochanter. A set of 22 fresh cadaveric femoral specimens were scanned with use of two-dimensional dual energy x-ray absorptiometry and then were tested to failure in a materials testing system, under three-point loading, with the ground impact vector aligned within the plane and along the bisector of the femoral neck-shaft angle. Failure locations generally corresponded to stress peak locations predicted by the curved beam model. Predicted failure loads correlated well with measured failure loads for femoral neck fractures (r=0.89; percent SE of estimate=23%) and some-what less well for intertrochanteric fractures (r=0.83; percent SE of estimate=29%). Overall predictions for failure load calculated from the maximum stress peak value over both locations corresponded to measured failure loads with an r value of 0.91 (percent SE of estimate=21%). This kind of structural approach to the analysis of data for hip bone mass has the potential to provide mechanistic interpretations of the statistical associations frequently shown between conventional bone mineral measures and either hip fracture risk in vivo or bone strength in vitro.

Cutaneous mucormycosis with subsequent visceral dissemination in a child with neutropenia: a case report and review of the pediatric literature

Primary cutaneous mucormycosis is a rare opportunistic fungal infection that is usually limited to the skin. We describe a primary cutaneous Rhizopus infection occurring at a site occluded by a sterile adhesive dressing in which the disease was viscerally disseminated at the time fo diagnosis. Mucormycosis should be considered in all ecthyma-like lesions in immunocompromised patients. It may be rapidly diagnosed by examination of hematoxylin-eosin and PAS-stained sections of the eschar base and a culture of a leading edge tissue aspirate. We review 21 cases of primary cutaneous mucormycosis in children and compare them with the present case.

The farnesyltransferase inhibitor FTI-277 radiosensitizes H-ras-transformed rat embryo fibroblasts

Many tumor cells have a greater resistance to ionizing radiation than their normal counterparts, suggesting that the development of drugs that can reduce that radioresistance would potentiate the efficacy of radiation therapy. Because activated H-ras expression has been shown to markedly increase radiation resistance in some transformed cells, the inactivation of H-ras would then be predicted to radiosensitize these tumor cells, while leaving normal cells unaffected. H-ras depends for activity upon farnesylation, which can be blocked by farnesylation inhibitors, including the compound FTI-277. In keeping with this prediction, inhibition of H-ras processing using FTI-277 resulted in higher levels of apoptosis after irradiation and increased radiosensitivity in H-ras-transformed rat embryo cells but did not affect control cells. These experiments suggest that farnesylation inhibitors may prove clinically useful as radiosensitizers of tumors that depend on ras function.

A multivariable analysis of clinical factors predicting for pathological features associated with local failure after radical prostatectomy for prostate cancer

PURPOSE

A multivariate analysis is used to determine the predictive value of pretreatment clinical indicators on pathologic features associated with local failure after radical prostatectomy in patients with prostate cancer.

METHODS AND MATERIALS

A retrospective review of the pathologic findings of 235 patients with adenocarcinoma of the prostate treated between 1990 and 1993 with a radical retropubic prostatectomy was performed. The preoperative clinical data including the serum prostate specific antigen, clinical stage, Gleason sum, and endorectal magnetic resonance scan findings are used to identify patients prior to definitive treatment who would be at high risk for having pathologic features associated with local failure at radical prostatectomy. Outcome prediction curves are constructed from a logistic regression multivariate analysis displaying the probability of pathologic involvement of the seminal vesicle, extracapsular disease, or positive surgical margins as a function of the preoperative prostate specific antigen and Gleason sum for the cases when the endorectal magnetic resonance scan is positive, negative, or not included in the multivariate analysis.

RESULTS

Factors identified on multivariate analysis as significant predictors of seminal vesicle invasion include endorectal magnetic resonance scan findings (p < 0.0001), and preoperative prostate specific antigen (p = 0.017). Endorectal magnetic resonance scan findings (p = 0.0016), preoperative prostate specific antigen (p = 0.0002), and Gleason sum (p < 0.0001) were significant predictors of extracapsular extension and preoperative prostate specific antigen (p < 0.0001) and Gleason sum (p = 0.03) were significant predictors of disease extending to the margins of resection. Clinical stage was not a significant predictor (p > 0.05) of pathologic features associated with local failure on multivariate analysis. As a single modality, endorectal surface coil magnetic resonance imaging was accurate 93%, 69%, and 72% of the time for predicting seminal vesicle invasion, transcapsular disease, and final pathologic stage, respectively. Failure to recognize microscopic penetration of the capsule found at the time of pathologic evaluation in a prostate gland with a grossly intact capsule accounts for the majority (70%) of the staging inaccuracies.

CONCLUSIONS

The use of the endorectal surface coil magnetic resonance scan findings in conjunction with both the serum prostate specific antigen and Gleason sum improves the clinical accuracy of predicting those patients at high risk for clinically unsuspected extraprostatic disease. In particular, for the subgroup of patients with moderately elevated prostate specific antigen (> 10-20 ng/mL) and intermediate grade clinically organ confined prostate cancer [Gleason sum: 5-7] where the specificity of these tests to predict for occult extraprostatic disease is suboptimal, the additional information obtained from the endorectal coil magnetic resonance scan allows the physician to definitively subgroup these patients into low and high risk for seminal vesicle invasion or transcapsular disease.

The use of clinical parameters in an interactive statistical package to predict pathological features associated with local failure after radical prostatectomy for prostate cancer

The capability of an interactive statistical package (ISP) to predict the patients whose pathologic findings at the time of radical prostatectomy for prostate cancer would require postoperative radiation therapy to prevent local failure is investigated. A retrospective review of the clinical pretreatment factors and pathologic findings of 174 patients with adenocarcinoma of the prostate treated from 1989 to 1993 with radical retropubic prostatectomy was performed and served as a knowledge base of the ISP. The pathologic findings of seminal vesicle involvement, gross transcapsular disease, and positive surgical margins are defined as outcomes associated with a high risk of local failure after radical prostatectomy and, thereby, requiring postoperative radiation therapy to decrease this risk. By using the pretreatment clinical factors including prostate-specific antigen (PSA), Gleason score, clinical stage, and endorectal magnetic resonance imaging (MRI) findings as input to the ISP, patients are identified from a test group of 50 cases with known pathologic outcome who would require postoperative radiotherapy to decrease local failure. Low- (0% to 33%), intermediate- (34% to 67%), and high-risk groups (68% to 100%) for pathologic features associated with local failure were predicted accurately (r > .95) by the ISP for the 50 test cases. Factors identified on univariate analysis by the ISP as significant predictors of local failure postoperatively include PSA > 20 (p < .001), clinical stage (p < .001), MRI finding of gross transcapsular disease (p < .001), MRI finding of seminal vesicle involvement (p < .001), and Gleason score (p < .003).(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocution: a review of 155 cases with emphasis on human factors

A review of 155 cases of electrocution were investigated to determine the role of human factors, such as carelessness and intoxication, as contributions. The cases were retrieved by computer coding from the repository of the Armed Forces Institute of Pathology, covering the period 1955-1988. The cases are predominantly of military origin. Cases were divided into low-voltage electrocution (N = 47), high-voltage electrocution (N = 79), lightning strikes (N = 16), and unclassified (N = 13). For each group, data is presented on the circumstances of the incident and the pathologic findings. Blatant carelessness, misuse or improper maintenance of equipment, and intoxication are analyzed as contributory factors.

Studies of the T1 and T2 of intracellular water as a function of frequency in normal and transformed fetal cells

Frequency-dependent values of the spin-lattice relaxation time (T1) and the spin-spin relaxation time (T2) have been obtained for intracellular water in normal and transformed Syrian hamster fetal fibroblasts. Values of T1 and T2 were obtained for normal and transformed cells at 24.3 (0.57 T), 100 (2.4 T), 300 (7.0 T), and 400 MHz (9.4 T). At each frequency, values of T1 were the same for both normal and transformed cells, whereas values of T2 were lower for one passage of transformed cells. As expected, T1 increased with frequency. However, T2 decreased with frequency for both normal and transformed cells. The frequency dependence of T2, was similar for all cells; thus, the ability of T2 to make a distinction between normal and transformed cells did not change with field.

An RME1-independent pathway for sporulation control in Saccharomyces cerevisiae acts through IME1 transcript accumulation

The RES1-1 mutation was isolated on the basis of its ability to allow MATa/MAT alpha diploid Saccharomyces cerevisiae cells to express a late sporulation-regulated gene, SPR3, in the presence of excess copies of RME1. RME1 is a repressor of meiosis that is normally expressed in cells that lack the a1/alpha 2 repressor encoded by MAT. The RES1-1 mutation also supports sporulation in mat-insufficient diploids. This phenotype does not result from a failure to express RME1 and is not due to activation of the silent copies of mating type information. RES1-1 activates sporulation by allowing IME1 accumulation in all cell types, irrespective of the presence of the MAT products. IME1 is still responsive to RME1 in RES1-1 cells, since double mutants (rme1 RES1-1) that are deficient at MAT can sporulate better than either single mutant. RES1-1 is not an allele of IME1.

Dependence of inessential late gene expression on early meiotic events in Saccharomyces cerevisiae

SPR3 is one of at least nine genes which are expressed in sporulating Saccharomyces cerevisiae cells at the time of meiosis I. We show below that strains homozygous for null alleles of SPR3 are capable of normal meiosis and the production of viable ascospores. We have also monitored SPR3 expression in a series of strains that are defective in meiotic development, using an SPR3:lacZ fusion carried on a single copy plasmid. beta-Galactosidase activity occurred at wild-type levels in diploid strains homozygous for mutations in spo13, rad50, rad57 and cdc9, but was greatly reduced in strains carrying cdc8 or spo7 defects. We conclude that SPR3 expression is a valid monitor of early meiotic development, even though the gene is inessential for the sporulation process.

Internal sclerostomy with the Nd: YAG contact laser versus thermal sclerostomy in rabbits

The authors undertook an investigation to evaluate the efficacy and complications of performing internal sclerostomy with the synthetic sapphire contact neodymium:YAG (Nd:YAG) laser compared with standard external thermal sclerostomy. Fifteen rabbits underwent internal laser sclerostomy in one eye; 12 additional rabbits underwent a standard external thermal sclerostomy in one eye. The fellow eyes served as controls. The differences between the groups in duration of functional blebs and pressure reduction were statistically significant (P = 0.034 and 0.0013, respectively). The evaluation of success (as determined by a pressure reduction greater than 3 mmHg between both eyes after digital pressure) using life-survival analysis indicated that the success rate of the laser-treated group was significantly different from the standard surgical group (P = 0.002). Histologically, there was less inflammation in the laser-treated group 2 days postoperatively. The complications of the laser treatment include focal injury to the overlying cornea, adjacent iris stroma, and lens.

The intraocular penetration and retinal toxicity of teicoplanin

We investigated the intraocular penetration and retinal toxicity of teicoplanin, a relatively new glycopeptide antibiotic with activity similar to vancomycin when used to inhibit staphylococci and other gram positive organisms, particularly Streptococcus faecalia. Topically administered teicoplanin penetrated poorly into the aqueous and vitreous in rabbit eyes. Subconjunctival injection of the drug yielded aqueous levels above the minimum inhibiting concentration (3.1 micrograms/ml) only at one hour after injection. In the vitreous, drug levels were above the mean inhibitory concentration at 30 minutes after the subconjunctival injection, but rapidly declined thereafter. The maximum nontoxic, single-dose, intravitreal injection was 750 micrograms/0.1 ml. Rabbits received 8 micrograms/ml of teicoplanin in an intravitreal infusion solution without demonstrable retinal toxicity.

Transcriptional regulation of sporulation genes in yeast

The relative transcription rates of three sporulation-regulated genes of yeast (SPR1, SPR2 and SPR3) were determined at intervals during sporulation, using a filter binding assay. The binding of in vivo labeled RNA to the corresponding DNAs increased 3- to 12-fold at the time of meiosis I, in parallel with the accumulation of the SPR transcripts. SPR1 and SPR3 mRNA abundance increased from less than 0.7 to 130 and 90 copies per cell, respectively, between the time of shift to sporulation medium and the initiation of spore formation. This represented a 150-to 200-fold increase in the steady-state levels of these RNAs. Similarly, the levels of beta-galactosidase present in sporulating cells harboring fusions between SPR3 and Escherichia coli lacZ increased at least 700-fold. We conclude that SPR1, SPR2 and SPR3 transcription is modulated during sporulation, possibly in response to earlier events in the process.

Factors influencing the recovery of dopamine sulfate in the assay of phenol sulfotransferase

Phenol sulfotransferase activity is often measured by incubating dopamine with a source of the enzyme and the sulfate donor 35S-3'-phosphoadensine-5'-phosphosulfate and then separating the product, 35S-dopamine sulfate, from the substrates using precipitation with barium hydroxide and zinc sulfate. Using dopamine sulfate standards and high performance liquid chromatography with dual-electrode electrochemical detection, we investigated the effects of several parameters on product recovery obtained with this procedure. Amounts of precipitants needed to produce maximal sample-to-blank ratios were determined using crude enzyme preparations from rat brain and human platelets incubated under conditions generating approximately 3 nM dopamine sulfate. Under these conditions, recovery of 3H-DAS standards was 70-80%. Increasing either the concentration of dopamine sulfate or the amounts of precipitants used resulted in concentration-dependent decreases in dopamine sulfate recovery. These data indicate that the recovery of product in this assay may vary with assay conditions, and should be carefully monitored and optimized. Caution should be exercised when using substrates other than dopamine in this assay procedure, since similar factors might also contribute to variable recovery of other products.

Intravitreal trifluorothymidine and retinal toxicity

Intraocular trifluorothymidine was administered to one group of albino rabbits as an intravitreal injection, and to a second group of albino rabbits in the infusion solution during pars plana vitrectomy. The eyes of both populations were evaluated with preoperative and postoperative indirect ophthalmoscopy, electroretinography, and histologic examination. From these data, it was determined that an intravitreal injection of 200 micrograms/0.1 ml and a vitrectomy solution containing a concentration of 60 micrograms/ml trifluorothymidine were nontoxic to the rabbit eye.