Production of nascent ribosome precursors within the nucleolar microenvironment of Saccharomyces cerevisiae

35S rRNA transcripts include a 5'-external transcribed spacer followed by rRNAs of the small and large ribosomal subunits. Their processing yields massive precursors that include dozens of assembly factor proteins. In Saccharomyces cerevisiae, nucleolar assembly factors form 2 coaxial layers/volumes around ribosomal DNA. Most of these factors are cyclically recruited from a latent state to an operative state, and are extensively conserved. The layers match, at least approximately, known subcompartments found in higher eukaryotic cells. ∼80% of assembly factors are essential. The number of copies of these assembly factors is comparable to the number of nascent transcripts. Moreover, they exhibit "isoelectric balance," with RNA-binding candidate "nucleator" assembly factors being notably basic. The physical properties of pre-small subunit and pre-large subunit assembly factors are similar, as are their 19 motif signatures detected by hierarchical clustering, unlike motif signatures of the 5'-external transcribed spacer rRNP. Additionally, many assembly factors lack shared motifs. Taken together with the progression of rRNP composition during subunit maturation, and the realization that the ribosomal DNA cable is initially bathed in a subunit-nonspecific assembly factor reservoir/microenvironment, we propose a "3-step subdomain assembly model": Step (1): predominantly basic assembly factors sequentially nucleate sites along nascent rRNA; Step (2): the resulting rRNPs recruit numerous less basic assembly factors along with notably basic ribosomal proteins; Step (3): rRNPs in nearby subdomains consolidate. Cleavages of rRNA then promote release of rRNPs to the nucleoplasm, likely facilitated by the persistence of assembly factors that were already associated with nucleolar precursors.

Engineering Human Circulating Monocytes/Macrophages by Systemic Deliverable Gene Editing

Delivery of plasmid DNA to transfect human primary macrophages is extremely difficult, especially for genetic engineering. Engineering macrophages is imperative for the treatment of many diseases including infectious diseases, cancer, neurological diseases, and aging. Unfortunately, plasmid does not cross the nuclear membranes of terminally differentiated macrophages to integrate the plasmid DNA (pDNA) into their genome. To address this issue, we have developed a core-shell nanoparticle (NP) using our newly created cationic lipid to deliver the anti-inflammatory cytokine IL-4 pDNA (IL-4pDNA-NPs). Human blood monocyte-derived macrophages (MDM) were effectively transfected with IL-4pDNA-NPs. IL-4pDNA-NPs were internalized in MDM within 30 minutes and delivered into the nucleus within 2 hours. Exogenous IL-4 expression was detected within 1 - 2 days and continued up to 30 days. Functional IL-4 expression led to M2 macrophage polarization in vitro and in an in vivo mouse model of inflammation. These data suggest that these NPs can protect pDNA from degradation by nucleases once inside the cell, and can transport pDNA into the nucleus to enhance gene delivery in macrophages in vitro and in vivo. In this research, we developed a new method to deliver plasmids into the nucleus of monocytes and macrophages for gene-editing. Introducing IL-4 pDNA into macrophages provides a new gene therapy solution for the treatment of various diseases.

Persistence of SARS-CoV-2 Antibodies in Vaccinated Health Care Workers Analyzed by Coronavirus Antigen Microarray

Recent studies provide conflicting evidence on the persistence of SARS-CoV-2 immunity induced by mRNA vaccines. Here, we aim to quantify the persistence of humoral immunity following vaccination using a coronavirus antigen microarray that includes 10 SARS-CoV-2 antigens. In a prospective longitudinal cohort of 240 healthcare workers, composite SARS-CoV-2 IgG antibody levels did not wane significantly over a 6-month study period. In the subset of the study population previously exposed to SARS-CoV-2 based on seropositivity for nucleocapsid antibodies, higher composite anti-spike IgG levels were measured before the vaccine but no significant difference from unexposed individuals was observed at 6 months. Age, vaccine type, or worker role did not significantly impact composite IgG levels, although non-significant trends towards lower antibody levels in older participants and higher antibody levels with Moderna vaccine were observed at 6 months. A small subset of our cohort were classified as having waning antibody titers at 6 months, and these individuals were less likely to work in patient care roles and more likely to have prior exposure to SARS-CoV-2.

Dual-sgRNA CRISPR/Cas9 knockout of PD-L1 in human U87 glioblastoma tumor cells inhibits proliferation, invasion, and tumor-associated macrophage polarization

Programmed death ligand 1 (PD-L1) plays a key role in glioblastoma multiforme (GBM) immunosuppression, vitality, proliferation, and migration, and is therefore a promising target for treating GBM. CRISPR/Cas9-mediated genomic editing can delete both cell surface and intracellular PD-L1. This systemic deliverable genomic PD-L1 deletion system can be used as an effective anti-GBM therapy by inhibiting tumor growth and migration, and overcoming immunosuppression. To target PD-L1 for CRISPR/Cas9 gene editing, we first identified two single guide RNA (sgRNA) sequences located on PD-L1 exon 3. The first sgRNA recognizes the forward strand of human PD-L1 near the beginning of exon 3 that allows editing by Cas9 at approximately base pair 82 (g82). The second sgRNA recognizes the forward strand of exon 3 that directs cutting at base pair 165 (g165). A homology-directed repair template (HDR) combined with the dual-sgRNAs was used to improve PD-L1 knockout specificity and efficiency. sgRNAs g82 and g165 were cloned into the multiplex CRISPR/Cas9 assembly system and co-transfected with the HDR template in human U87 GBM cells (g82/165 + HDR). T7E1 analysis suggests that the dual-sgRNA CRISPR/Cas9 strategy with a repair template was capable of editing the genomic level of PD-L1. This was further confirmed by examining PD-L1 protein levels by western blot and immunofluorescence assays. Western blot analysis showed that the dual-sgRNAs with the repair template caused a 64% reduction of PD-L1 protein levels in U87 cells, while immunostaining showed a significant reduction of intracellular PD-L1. PD-L1 deletion inhibited proliferation, growth, invasion and migration of U87 cells, indicating intracellular PD-L1 is necessary for tumor progression. Importantly, U87 cells treated with g82/165 + HDR polarized tumor-associated macrophages (TAM) toward an M1 phenotype, as indicated by an increase in TNF-α and a decrease in IL-4 secretions. This was further confirmed with flow cytometry that showed an increase in the M1 markers Ly6C + and CD80 +, and a decrease in the M2 marker CD206 + both in vitro and in vivo. Utilizing dual-sgRNAs and an HDR template with the CRISPR/Cas9 gene-editing system is a promising avenue for the treatment of GBM.

An audit on coronary artery calcium scoring in the mercy university hospital, co. cork, ireland

Funding Acknowledgements

Type of funding sources: None.

Background

Coronary artery calcium (CAC) testing is an imaging technique used to non-invasively assess calcification within the coronary arteries. It has emerged as a reliable surrogate measure of coronary artery disease where higher risk individuals are more likely to benefit from medications such as aspirin and statins. A high calcium score should prompt further diagnostic tests for coronary artery disease. This was a single centre audit designed to assess the current role and the clinical implications of CAC testing in our university hospital, Ireland.

Methods

This was a retrospective chart review of all patients who underwent CAC testing in MUH from 1st January 2019 to 31st December 2020. Patients were recruited from the CAC database within the hospital radiology department. Demographic data, indication for CAC testing, medication records and results of invasive coronary angiography were obtained from the medical records. Assessment of CAC scores and percentiles from all patients were recorded from the radiology results system.

Results

Of the 218 participants, 48.6% were male and the mean age was 53.7 (± 9.7) years. The most common risk factors were hypercholesterolaemia (65.1%), family history of premature coronary artery disease (48.6%) and hypertension (31.2%). CAC results were as follows: 50.5% had a score of 0, 25.2% had a score of 1-99, 12.4% had a score of 100-399, 6.4% had a score of 400-999, and 5.5% had a score of ≥1000. The most common indications for CAC testing were risk factors (45.5%) and symptoms (38.0%). CAC testing indications were unretrievable on the database for 31 patients (14.2%). CT coronary angiography was performed in 57 patients (26.1%), while 30 patients (13.8%) had invasive coronary angiography. On invasive coronary angiography, 8 patients (3.7%) were reported to have obstructive disease and 25 patients (11.5%) had non-obstructive disease. Following CAC testing, antiplatelet therapy was started in 15 patients (6.9%). Statin therapy was started in 28 patients (12.4%). The maintenance and modification of previous statin therapy was noted in 67 patients (30.3%).

Conclusion

CAC testing is a useful non-invasive diagnostic test which can be used to identify individuals at risk of obstructive coronary artery disease and guide initiation of risk modifying therapy. The cohort of patients currently undergoing CAC testing in our hospital are largely asymptomatic patients with cardiovascular risk factors. The results of these tests led to commencement of risk modifying treatment in less than 20% of patients and only a small proportion of patients required follow-on invasive coronary angiography for further investigation of their coronary artery anatomy. These results show that CAC testing use in our hospital is in line with international guidelines and suggest that the use of CAC testing decreases the requirement for invasive coronary angiography in low-risk, asymptomatic patients.

A Pilot Microbiota Study in Parkinson's Disease Patients versus Control Subjects, and Effects of FTY720 and FTY720-Mitoxy Therapies in Parkinsonian and Multiple System Atrophy Mouse Models

BACKGROUND

Parkinson's disease (PD) and multiple system atrophy (MSA) patients often suffer from gastrointestinal (GI) dysfunction and GI dysbiosis (microbial imbalance). GI dysfunction also occurs in mouse models of PD and MSA.

OBJECTIVES

To assess gut dysfunction and dysbiosis in PD subjects as compared to controls, identify potential shared microbial taxa in humans and mouse models of PD and MSA, and to assess the effects of potential therapies on mouse GI microbiota.

METHODS

In this human pilot study, GI function was assessed by fecal consistency/frequency measured using the Bristol Stool Form Scale and GI transit time assessed using Sitzmarks pills and abdominal radiology. Human and mouse microbiota were analyzed by extracting fecal genomic DNA followed by 16S rRNA sequencing.

RESULTS

In our PD patients genera Akkermansia significantly increased while a trend toward increased Bifidobacterium and decreased Prevotella was observed. Families Bacteroidaceae and Lachnospiraceae and genera Prevotella and Bacteroides were detected in both humans and PD mice, suggesting potential shared biomarkers. In mice treated with the approved multiple sclerosis drug, FTY720, or with our FTY720-Mitoxy-derivative, we saw that FTY720 had little effect while FTY720-Mitoxy increased beneficial Ruminococcus and decreased Rickenellaceae family.

CONCLUSION

Akkermansia and Prevotellaceae data reported by others were replicated in our human pilot study suggesting the use of those taxa as potential biomarkers for PD diagnosis. The effect of FTY720-Mitoxy on taxa Rikenellaceae and Ruminococcus and the relevance of S24-7 await further evaluation. It also remains to be determined if mouse microbiota have predictive power for human subjects.

TAMI-14. NANOPARTICLE DELIVERY OF PD-L1 CRISPR/CAS9 PLASMID DNA FOR ANTI-GLIOBLASTOMA IMMUNOTHERAPY

Glioblastoma multiforme (GBM) is a devastating cancer that develops from astrocytes in the brain. GBM is fast acting and kills 90% of patients within 5 years. Several immunotherapies have been developed to treat GBM, however, major challenges still persist. For example, checkpoint proteins such as programmed cell death protein 1 (PD-1) and its ligand, programmed death ligand 1 (PD-L1), are upregulated in GBM cells to evade the immune system. Targeting PD-L1 for genetic knockdown is thus a promising avenue for the treatment of GBM. However, PD-L1 protein inhibitors have been shown to cause immune overreaction and toxicity, therefore requiring new technologies. CRISPR/Cas9 gene editing has been widely used for the study and treatment of many diseases, but has not been extensively studied for the treatment of GBM. The main challenge is developing a gene delivery platform for the delivery of CRISPR/Cas9 plasmid DNA (pDNA). Many viral vectors have been used for the delivery of pDNA, but unfortunately are associated with high toxicity. Nanotechnology is emerging as a new platform for the delivery of pDNA as it shows high transfection efficiency with low cytotoxicity. We developed a cationic core-shell nanoparticle (NP) capable of carrying CRISPR/Cas9 pDNA. This plasmid contains multiple guide RNA (gRNA) expression cassettes for the knockdown of PD-L1. PDL1gRNA-CRISPR/Cas9pDNA-NPs were taken up by U87 cells within 30 minutes, and entered into the nucleus at 2 hours. The effective delivery of PDL1gRNA-CRISPR/Cas9pDNA-NPs led to the expression of PD-L1 gRNA and Cas9 enzyme, and the knockdown of PD-L1. Regulation of immune balance was determined after PD-L1 knockdown in vitro and in vivo. Our study shows the potential of NP-based PDL1gRNA-CRISPR/Cas9 delivery as an anti-GBM immunotherapy for clinical applications.

Open splenectomy in Jamaican children with sickle cell disease

A total of 110 patients with sickle cell disease who had open splenectomy at the University Hospital of the West Indies over a 10-year period are reviewed Patients with homozygous sickle cell disease numbered 94, S beta0 and S beta+ thalassaemias (11 and 4 respectively) and one patient with SC disease. Postoperative acute chest syndrome was the most common complication (9 of 110). There were no life threatening emergencies and no mortalities. Eleven patients received preoperative blood transfusion and operative times were short averaging 60 minutes among the 110 patients. Open splenectomy remains the gold standard for patients with sickle cell disease requiring splenectomy.

Quantitative analysis of glutamate transporter mRNA expression in prefrontal and primary visual cortex in normal and schizophrenic brain

Abnormalities of the glutamatergic system in schizophrenia have been identified in numerous studies, but little is known about the role of glutamate transporters and their messenger RNA (mRNA) expression. In addition, the abundances of the two major isoforms of human excitatory amino acid transporter 2 (EAAT2) or its rat ortholog, glutamate transporter 1, have never been compared in a quantitative manner. Using quantitative reverse transcription-polymerase chain reaction, we established that the expression of the EAAT1, EAAT2a, EAAT2b, and EAAT3 transcripts was not different in the dorsolateral prefrontal and primary visual cortices of persons with schizophrenia relative to matched controls. EAAT2a expression was about 25-fold and 10-fold higher than EAAT2b in human and rat brain, respectively. The data provided no evidence of an effect of antipsychotic medications on the mRNA expression of the glutamate transporters. However, because most of the schizophrenic subjects in the cohort had been treated with antipsychotics for many years, it is still possible that changes in transporter expression were masked by medication effects.

Unstable angina following acute MI in a patient with bilateral coronary artery fistulae: an unusual presentation of coronary steal?

We report a 57-year-old woman with acute myocardial infarction and cardiac arrest who subsequently developed unstable angina. The possibility of a coronary steal syndrome contributing to her unstable angina arises in view of the presence of bilateral coronary artery fistulae between two atherosclerotic coronary arteries and the main pulmonary artery.

Efficacy and safety of combination simvastatin and colesevelam in patients with primary hypercholesterolemia

PURPOSE

To examine the efficacy and safety of colesevelam hydrochloride, a novel, nonsystemic, lipid-lowering agent, when coadministered with starting doses of simvastatin in a multicenter, randomized, double-blind, placebo-controlled trial.

PATIENTS AND METHODS

Subjects with hypercholesterolemia (plasma low density lipoprotein [LDL] cholesterol level > 160 mg/dL and triglyceride level < or = 300 mg/dL) were randomly assigned to receive daily doses of placebo (n = 33), colesevelam 3.8 g (recommended dose, n = 37), simvastatin 10 mg (n = 35), colesevelam 3.8 g with simvastatin 10 mg (n = 34), colesevelam 2.3 g (low dose, n = 36), simvastatin 20 mg (n = 39), or colesevelam 2.3 g with simvastatin 20 mg (n = 37), for 6 weeks.

RESULTS

Mean LDL cholesterol levels decreased relative to baseline in the placebo group (P < 0.05) and in all active treatment groups (P < 0.0001). For groups treated with combination therapy, the mean reduction in LDL cholesterol level was 42% (-80 mg/dL; P < 0.0001 compared with baseline), which exceeded the reductions for simvastatin 10 mg (-26%, -48 mg/dL) or 20 mg (-34%, -61 mg/dL) alone, or for colesevelam 2.3 g (-8%, -17 mg/dL) or 3.8 g (-16%, -31 mg/dL) alone (P < 0.001). The effects of combination therapy on serum HDL cholesterol and triglyceride levels were similar to those for simvastatin alone. Side effects were similar among treatment groups, and there were no clinically important changes in laboratory parameters.

CONCLUSION

Coadministration of colesevelam and simvastatin was effective and well tolerated, providing additive reductions in LDL cholesterol levels compared with either agent alone.

Four-dimensional dielectric property image obtained from electron spectroscopic imaging series

We have demonstrated a new quantitative method to characterize two-dimensional distributions of energy-dependent dielectric function of materials from low loss electron spectroscopic image (ESI) series. Two problems associated with extracted image-spectrum from the low-loss image series, under-sampling and loss of energy resolution, were overcome by using fast Fourier transformation (FFT) interpolation and maximum entropy deconvolution method. In this study, Black Diamond/Si3N4/SiO2/Si-substrate dielectric layer designed for copper metallization was used as the sample. We show that the reconstructed (FFT interpolated and maximum entropy deconvoluted) image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional electron energy-loss spectroscopy spectra. Since the analysis of the dielectric function is sensitive to the local thickness of the specimen using Kramers-Kronig analysis, we also developed a new method to quantitatively determine the dielectric constant for low-k materials. We have determined the thickness of the Black Diamond using the extrapolated thickness method from the materials of known dielectric constants. Using Kramers-Kronig formula, the dielectric function map can be deduced from two-dimensional reconstructed single scattering spectra with providing the information of thickness. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series.

Comparison of myocardial oxygen consumption using 11C acetate positron emission tomography scanning in a working and non-working heart transplant model

OBJECTIVE

In acute cardiac rejection, changes in myocardial oxygen consumption occur; non-invasive detection of these metabolic changes would have obvious clinical utility. In the classic cervical, heterotopic, canine, transplant model, the heart is non-working. It has a low myocardial oxygen consumption. Creation of a working model with normal myocardial oxygen consumption would enhance validity of non-human studies.

METHODS

Clearance of 11C acetate was determined by positron emission tomography (PET) scanning and compared with myocardial oxygen consumption in normal and transplanted canine hearts. Donor hearts from mongrel dogs (2.5-3 kg; n=4) were transplanted into the neck of adult beagles (12-15 kg; n=4), no immunosuppression was given. Two non-working hearts were modified to eject only coronary flow via the right ventricle. In two hearts, a novel working model was created with aortic regurgitation to load the left ventricle. Working and non-working hearts underwent PET scanning on post-operative days 2 and 4. Normal dog hearts (n=2) and native hearts of transplanted dogs (n=3) were used to validate the scanning technique. Coronary sinus and aortic oxygen saturation data along with myocardial blood flow (radiolabeled microspheres) confirmed that clearance of 11C acetate in normal and transplanted hearts followed a bi-exponential model.

RESULTS

Myocardial oxygen consumption was correlated with the rate constant of 11C acetate rapid phase clearance (r=0.91) in normal and transplanted hearts. The working hearts had increased myocardial oxygen consumption compared to non-working hearts.

CONCLUSIONS

This study (1) introduces a model of a working heterotopic cardiac transplantation with near-normal oxygen consumption; and (2) demonstrates that regional myocardial oxygen consumption in transplanted hearts can be detected by 11C acetate PET.

Cariporide Aventis

Cariporide is a sodium/hydrogen ion exchange inhibitor under development by Aventis Pharma, formerly Hoechst Marion Roussel (HMR), as a potential treatment for myocardial infarction (MI), ischemic damage due to angioplasty and reperfusion following thrombolysis. It is in phase II/III trials [221118]. Cariporide inhibits the interchange of sodium ions and protons in myocardial cells during unstable angina or MI when cells metabolize anerobically. This prevents lactic acid production and an increase in calcium levels which causes cardiac arrhythmias and heart tissue death [253616]. Approval filings in the US and EU had been scheduled for the second half of 1999 [309323]. In 1998, HMR expected that the drug would be launched in 2000, and would have a potential market in excess of DM 750 million [288651]. By May 2000, however, the launch date had been revised for between 2003 and 2004 [370971], [379336]. Aventis is expecting peak sales to be around $400 million [333420]. In March 1999, HMR reported that trials for MI had been suspended after results from the phase III GUARDIAN trial did not achieve statistical significance [353173]. In August 2000, however, a phase II trial in patients with acute MI was underway [379051]. A phase III trial in patients undergoing coronary artery bypass grafting (CABG) was expected to begin in early 2000 after the results of ongoing dose-optimization studies in CABG patients are known. As of May 2000, however, this trial had not begun, although based on promising CABG-related results of the GUARDIAN trial, the phase III trial in this indication is expected to begin in the first half of 2001 [370971]. There were also plans for the initiation of European phase II trials in acute MI patients; similar phase II trials are ongoing in Japan. In September 2000, Merrill Lynch predicated launch in 2003 [383742]. In February 1999, Lehman Brothers predicted a 70% probability that cariporide would reach market in the US/Europe and 50% probability that it would reach the Japanese market. They also predicted a US/European launch in 2000 with peak sales of $400 million in 2008 and a Japanese launch in 2002 with peak sales of $100 million [319225].

Targeted inhibition of wound-induced PAI-1 expression alters migration and differentiation in human epidermal keratinocytes

In the adult epidermis, keratinocytes do not normally express the type-1 inhibitor of plasminogen activator (PAI-1). Basal epithelial cell-specific PAI-1 synthesis, however, accompanies epidermal wound repair in vivo in which PAI-1 transcripts and immunoreactive protein are confined to epithelial cells in the migrating tongue and the hyperproliferative zone. A model system using human keratinocytes (HaCaT cells) was developed to assess functional relationships between epithelial growth state transitions and PAI-1 expression. PAI-1 synthesis was maximal in low population density, exponentially growing HaCaT cultures; relative PAI-1 mRNA and protein levels progressively declined as cells attained, and were maintained in, a postconfluent condition. While the fraction of PAI-1(+) keratinocytes remained stable (at approximately 85-90% of the population) throughout the culture period, both PAI-1 mRNA abundance and mean cell-associated PAI-1 protein declined by >90% during prolonged (i.e., 8-day) growth arrest. Similar to epidermal trauma in vivo, scrape wounding of HaCaT monolayers resulted in the rapid and location-specific induction of PAI-1 protein (an increase of 11- to 16-fold relative to unwounded cultures) in cells immediately bordering the injury site. PAI-1 expression was evident in keratinocytes that comprised the opposed migrating fronts and remained elevated until wound closure. Down-regulation of PAI-1 synthesis in HaCaT cells transfected with an inducible LacSwitch-based antisense vector system markedly impaired both the rate and the extent of wound closure. All injuries created in antisense PAI-1 monolayers remained unhealed at day 8 postinjury compared to the 3-day complete repair typical of control cultures. Vector-driven modulation of PAI-1 synthesis was also associated with an increase in the percentage of suprabasal-type keratinocytes within the wound field. PAI-1 expression by migrating HaCaT cells appears necessary to maintain the basal epidermal phenotype and/or appropriate cell-to-substrate adhesion during injury repair.

Solvent replacement for green processing

The implementation of the Montreal Protocol, the Clean Air Act, and the Pollution Prevention Act of 1990 has resulted in increased awareness of organic solvent use in chemical processing. The advances made in the search to find "green" replacements for traditional solvents are reviewed, with reference to solvent alternatives for cleaning, coatings, and chemical reaction and separation processes. The development of solvent databases and computational methods that aid in the selection and/or design of feasible or optimal environmentally benign solvent alternatives for specific applications is also discussed.

Global cardiac function using fast breath-hold MRI: validation of new acquisition and analysis techniques

Calculation of global cardiac function parameters has been validated using fast, segmented k-space, breath-hold, gradient-echo, magnetic resonance images. Images of phantoms, experimental animals, normal volunteers, and patients were acquired with a 1.5 T clinical scanner. Humans were imaged using two phased-array surface coils in multicoil mode. Myocardial contours were extracted using a new interactive, semi-automated method based on the active contour model method. Images were acquired in the short-axis orientation, and, using a new imaging and analysis strategy, in rotating plane long-axis orientations, to provide better definition of the valve planes and the apex, and also to reduce the number of slices (compared with the short-axis method) required to sample the whole heart. Validation was accomplished through calculation of the volumes of phantoms and left and right ventricular masses of animal hearts. Functional parameters from MRI were compared with those from echocardiograms and radionuclide angiograms in normal volunteers and patients, respectively.

Salvage of the severely traumatized lower extremity

The use of microsurgical techniques has significantly altered the management of lower extremity trauma. Indications for amputation or salvage continue to change, as microsurgical transplants have become more commonplace. Reconstruction of a severely traumatized leg usually involves multiple complicated procedures, each of which can cause its own set of complications. The historically high rate of complications of these procedures and the fact that the resultant limb is never completely normal has led some to the conclusion that severely traumatized limbs should not be salvaged. In order to evaluate our own results in light of these considerations we have reviewed our most recent experience with this difficult problem.

Proteinases of rat mast cells. Peritoneal but not intestinal mucosal mast cells express mast cell proteinase 5 and carboxypeptidase A

Six basic proteins of 26 to 38 kDa with isoelectric points (pI) &gt; or = 8.5 were abundant in proteins separated by two-dimensional SDS-PAGE from adult rat peritoneal mast cells (MC). One was identified previously as rat mast cell proteinase (RMCP) 1, a chymase of 26 to 28 kDa, pI &gt; 9.0. Microsequence analyses showed that two polypeptides of about 29 and 30 kDa had NH2 terminal amino acid sequences homologous to mouse MC proteinase 5 (MCP-5), whereas the amino terminals of the 33, 35, and 36 kDa proteins were homologous to MC carboxypeptidase A (MC-CPA). Rabbit Abs produced against synthetic peptides of the identified NH2 terminal sequences were used in immunoblot studies. At least three proteins reacted with Abs to MC-CPA, whereas Abs to MCP-5 detected three adjacent polypeptides, rather than just the two identified by using microsequence analysis. Removal of oligosaccharide side chains using peptide:N-glycosidase F reduced the heterogeneity of each set of three polypeptides (MCP-5 and MC-CPA) to a band of each protein of a lower M(r). The serine proteinase inhibitor [3H]diisopropylfluorophosphate ([3H]DFP) bound to a proteinase of 30 to 35 kDa, which is probably MC tryptase (pI &lt; or = 6.0). Immunoblot analysis of proteins from intestinal mucosal mast cells showed RMCP-2, but not RMCP-1, MCP-5, or MC-CPA. This is the first report of MCP-5 in the rat and of clearly distinguishable glycosylated forms of MC CPA. These proteinases appear to be restricted in their distribution to selected MC populations, but little is known about their functions.

Proteinases of rat mast cells. Peritoneal but not intestinal mucosal mast cells express mast cell proteinase 5 and carboxypeptidase A

Six basic proteins of 26 to 38 kDa with isoelectric points (pI) > or = 8.5 were abundant in proteins separated by two-dimensional SDS-PAGE from adult rat peritoneal mast cells (MC). One was identified previously as rat mast cell proteinase (RMCP) 1, a chymase of 26 to 28 kDa, pI > 9.0. Microsequence analyses showed that two polypeptides of about 29 and 30 kDa had NH2 terminal amino acid sequences homologous to mouse MC proteinase 5 (MCP-5), whereas the amino terminals of the 33, 35, and 36 kDa proteins were homologous to MC carboxypeptidase A (MC-CPA). Rabbit Abs produced against synthetic peptides of the identified NH2 terminal sequences were used in immunoblot studies. At least three proteins reacted with Abs to MC-CPA, whereas Abs to MCP-5 detected three adjacent polypeptides, rather than just the two identified by using microsequence analysis. Removal of oligosaccharide side chains using peptide:N-glycosidase F reduced the heterogeneity of each set of three polypeptides (MCP-5 and MC-CPA) to a band of each protein of a lower M(r). The serine proteinase inhibitor [3H]diisopropylfluorophosphate ([3H]DFP) bound to a proteinase of 30 to 35 kDa, which is probably MC tryptase (pI < or = 6.0). Immunoblot analysis of proteins from intestinal mucosal mast cells showed RMCP-2, but not RMCP-1, MCP-5, or MC-CPA. This is the first report of MCP-5 in the rat and of clearly distinguishable glycosylated forms of MC CPA. These proteinases appear to be restricted in their distribution to selected MC populations, but little is known about their functions.

Interferons differentially regulate histamine and TNF-alpha in rat intestinal mucosal mast cells

Mast cell (MC) heterogeneity has been well characterized in the rat where it has been shown that connective tissue MC, often represented by peritoneal MC (PMC), and the intestinal mucosal MC (IMMC) exhibit many differences in mediator content and responsiveness to secretagogues and anti-allergic drugs. Pretreatment (20 hr) of PMC with interferon (IFN)-alpha/beta or IFN-gamma, significantly reduced antigen-stimulated histamine release. By contrast, for IMMC, the same IFN treatment did not modify antigen-stimulated histamine secretion. Although IFN treatment differentially modulates histamine secretion from PMC and IMMC, pretreatment of both MC types with IFN-alpha/beta or IFN-gamma inhibited their tumour-necrosis factor-alpha (TNF-alpha)-dependent cytotoxicity. In 20 hr of culture, IMMC spontaneously released 98 pg/10(6) MC of TNF-alpha, whereas PMC released about threefold more TNF-alpha, 282 pg/10(6) MC. In addition, direct assessment of stored TNF-alpha established that IMMC store less TNF-alpha (68 pg/10(6) MC) than PMC (404 pg/10(6) MC). In summary, TNF-alpha content of PMC and IMMC was different, but IFN inhibited TNF-alpha-dependent cytotoxicity by both MC types. By contrast, treatment with IFN-alpha/beta or IFN-gamma inhibits antigen-induced histamine secretion by PMC, but does not modify antigen-induced histamine secretion by IMMC. Thus, IFN differentially regulate the secretion of histamine and TNF-alpha in PMC and IMMC.

MOMs (multiples of the median) and DADs (discriminant aneuploidy detection): improved specificity and cost-effectiveness of biochemical screening for aneuploidy with DADs

OBJECTIVE

Our purpose was to assess the efficacy of double- and triple-screening paradigms for Down syndrome and to develop a more logical, statistical approach to risk prediction that will decrease the cost of screening and allow the incorporation of new parameters appropriately weighted for their contribution.

STUDY DESIGN

Data from 24,504 patients who had biochemical screening for Down syndrome by single (alpha-fetoprotein), double (alpha-fetoprotein, beta-human chorionic gonadotropin), or triple screening (alpha-fetoprotein, beta-human chorionic gonadotropin, unconjugated estriol) who had complete outcome information were analyzed by (1) existing gaussian-based methods, (2) the Glasgow ratio method, and (3) a new statistical approach (i.e., directly adjusted data sets for discriminant aneuploidy detection [DADs])

RESULTS

By use of individual risk-based thresholds for "at risk" status, both double and triple screening performed far better than single screening, but the percentages of patients at risk varied widely. When the percentages at risk were held constant, the sensitivity of double and triple screenings was similar, suggesting that there are no benefits of using estriol as a third marker. For 25,000 patients the use of only alpha-fetoprotein and beta-human chorionic gonadotropin would save about $500,000, with no decrease in sensitivity. With the DADs approach a statistically sound model giving more stable estimates was developed that permits each factor to be analyzed for its own explained proportion of variance and allows each parameter to have different weighting. For this data set the same sensitivity was seen with, conservatively, a 1% reduction in the percentage of patients at risk, which would reduce by 250 the number of amniocenteses, at a further savings of about $400,000.

CONCLUSIONS

By use of existing methods, double screening is equally as effective as triple screening, so that the expense of estriol is unnecessary. The DADs approach, by allowing for variable weighting of parameters, lowers the at risk percentage and will permit a much more flexible approach as new parameters become available. Changing to DADs and eliminating estriol should achieve higher specificity for the same sensitivity and save, conservatively, about $900,000 in this series. Extrapolated nationally, if confirmed, the annual savings could approach $72,000,000.

Nutritional status of Kadazan children in a rural district in Sabah, Malaysia

The nutritional status of 896 Kadazan children below 6 years of age from 23 villages of Tambunan District were studied. When stunting and wasting were defined as those who were below two standard deviations of height-for-age and weight-for-height (Waterlow et al, 1977) and based on the National Center for Health Statistics reference population, 67.6% of boys and 66.8% of girls were stunted while 12.3% of boys and 8.3% of girls were wasted. Weaning foods and toddler feeding practices were unsatisfactory. The role of health education on child care and feeding practices is emphasized.

Synergism of mutant frequencies in the mouse lymphoma cell mutagenicity assay by binary mixtures of methyl methanesulfonate and ethyl methanesulfonate

The effect of mixed mutagen exposures on the rate and type of induced mutants was studied in the L5178Y/TK+/-----TK-/- mouse lymphoma cell mutagenicity assay. In this assay, exposure to ethyl methanesulfonate (EMS) results in more mutants that form large colonies than small colonies. Exposure to methyl methanesulfonate (MMS) results in more mutants that form small colonies than large colonies. Other reports in the literature suggest that large colony TK-/- mutants appear to result from small-scale, perhaps single-gene mutations, and that small-colony TK-/- mutants appear to be associated with chromosomal mutations. Treating cells for 4 h with simple, 2-component mixtures containing 6.45 micrograms/ml MMS and either 261, 392, 560 or 712 micrograms/ml EMS resulted in synergism of mutants at each mixture level. The frequencies of total mutants were synergized 12, 20, 35 and 72%, respectively, in mixed exposures with graded doses of EMS, above the sums of the mixture components. Small colony mutants were synergized to a greater extent than large colony mutants. The frequencies of small colony mutants in mixed exposures were increased 31, 54, 73 and 123%, respectively, while the frequencies of large colony mutants were increased -7, -6, 11 and 39%. Statistical analyses provide strong evidence of synergism (within the limits of the assay) for total and small-colony mutants at all doses of EMS tested, and for large-colony mutants above 400 micrograms/ml EMS. Similar magnitudes of synergism resulted when other constant levels of MMS (4.30 or 8.60 micrograms/ml) were mixed with the same graded doses of EMS. The degree of synergism was dependent on EMS concentration but not on MMS concentration.

A new model for computerized clinical electron beam dosimetry

Clinical electron beams consist of primary electrons, primary bremsstrahlung generated in the regular photon and electron collimator system determining the composite beam, and some short-range contaminant photon and electron scatter arising from the lower parts of the standard or regular electron applicator. Any beam-shaping insert placed inside the applicator causes some extra ("contaminant") bremsstrahlung and electron scatter. The new dose calculation model is based on separate treatment of these components. For the calculation of the primary electron dose we use experimentally determined electron scatter functions and differential electron scatter functions. The primary bremsstrahlung is treated as an unflattened but otherwise regular x-ray beam. The contaminant components arising from the rim area of the regular electron collimator and from beam-shaping inserts are considered separately. The behavior of the in-air ionization profiles is described using the concepts of effective electron source position and effective electron source diameter. The model has been tested for several electron energies.

Improvement of the lipid profile during long-term administration of pindolol and hydrochlorothiazide in patients with hypertension

The effect of the combined administration of pindolol (10 or 20 mg daily) and hydrochlorothiazide (50 mg daily) on the serum lipid and lipoprotein levels of 34 hypertensive patients was investigated for 6 to 18.5 months (mean 13.3). Placebo control data were compared with the results obtained during treatment periods in each patient by paired t tests. Mean levels of high-density lipoprotein cholesterol increased by 17% (p less than 0.01), low-density lipoprotein cholesterol decreased by 4% (p less than 0.01) and the high-density lipoprotein: low-density lipoprotein cholesterol ratio increased by 28% (p less than 0.01). Total serum cholesterol, serum triglycerides and very low-density lipoprotein cholesterol showed no statistically significant changes from control values. These findings suggest that the long-term administration of this beta blocker combined with a diuretic results in serum lipid changes considered beneficial in the evaluation of risk factors for coronary artery disease.

Organization and sequences of the diversity, joining, and constant region genes of the human T-cell receptor beta chain

The organization and sequences of the human beta-chain T-cell receptor diversity, joining, and constant region segments are described. The beta chain of the human T-cell receptor, analogous to the mouse counterpart, consists of two distinct constant region genes approximately equal to 10 kilobases apart. The two constant region genes, C beta 1 and C beta 2, are very similar not only in sequence but also in genomic organization. The coding sequences of each of these C beta constant region genes are divided into four exons. The first two exons encode most of the extracellular constant domain. The third exon encodes a major part of the presumed transmembrane portion, and the last exon contains the cytoplasmic coding sequence as well as 3' untranslated sequences. Except for a stretch of approximately equal to 95 highly conserved nucleotides extending 3' of the first exon of the C region genes, little homology can be found between the intron sequences of C beta 1 and C beta 2. A small cluster of joining region (J beta) gene segments is located approximately equal to 5 kilobases upstream of each of these two constant regions. The first cluster, J beta 1, contains six functional J gene segments while the second, J beta 2, contains seven functional J gene segments. In addition, diversity region (D beta) gene segments are located approximately equal to 600 base pairs upstream of each J beta. Recombinational signals containing highly conserved heptamer and nonamer sequences separated by 12 or 23 bases are found adjacent to all of these D beta and J beta gene segments. These signal sequences are thought to be involved in the somatic recombination processes. These results indicate that what appears to be a gene duplication event giving rise to these two distinct regions must have arisen a long time ago in the evolution of this gene locus.

Analysis of cDNA clones specific for human T cells and the alpha and beta chains of the T-cell receptor heterodimer from a human T-cell line

We report the isolation and characterization of 19 classes of nonrearranging T cell-specific cDNA clones and two cDNA clones encoding the alpha and beta chains of the T-cell antigen receptor from a human T-cell line, Jurkat. Results indicate that the human alpha-chain gene, like its beta-chain counterpart, undergoes somatic rearrangement in T cells. In addition, it shows sequence homology to its beta-chain counterpart and immunoglobulin, indicating that the human alpha chain is also a member of the immunoglobulin supergene family. Sequence comparison suggests that the alpha chain also may be composed of variable (V), diversity (D), joining (J), and constant (C) region gene segments. The protein deduced from the cDNA sequence has a molecular weight of 29,995 and possesses six potential N-glycosylation sites. The availability of alpha- and beta-chain genes of the T-cell receptor from the same T-cell line provides tools to study their possible roles in recognition of antigens and major histocompatibility complex products by the human T-cell receptor.

Gene rearrangement in cells with natural killer activity and expression of the beta-chain of the T-cell antigen receptor

The mammalian host defence system can be divided broadly into adaptive and non-adaptive immunity. Adaptive immunity is acquired and is mediated by B and T lymphocytes. Non-adaptive immunity is mediated in part by a small subclass of heterogeneous peripheral blood mononuclear cells. This population, termed null cells, consists of haematopoietic precursors and cells mediating natural killer (NK) activity and antibody-dependent cellular cytotoxicity (ADCC). NK cells are a class of non-adherent, non-phagocytic, rapidly cytotoxic lymphocytes which can efficiently lyse a wide variety of tumour cells, virally infected cells and immature cell types of normal origin. Despite the broad range of targets, only a limited number of specificities are thought to be involved in target-cell recognition. Morphologically, NK cells are large granular lymphocytes, but they have been shown to exhibit cell-surface markers characteristic of both T cells and monocytes, raising doubt over their lineage. The recent cloning of the beta-chain of the T-cell antigen receptor has now allowed us to investigate whether some NK cells are T-cell-related. We have examined rearrangement and expression of the beta-chain of the T-cell receptor in cloned murine NK cell lines and fresh murine NK cell populations, and our results support the hypothesis that a subpopulation of NK cells is related to T cells and provide basis for examining whether some NK activity is mediated by a small number of T-cell receptors.

Somatic rearrangement of T-cell antigen receptor gene in human T-cell malignancies

A cDNA clone representing the gene encoding the beta chain of the human T-cell antigen receptor has been isolated recently. By using fragments of this cDNA as hybridization probes in Southern blot analysis of restriction endonuclease-digested genomic DNA, we have now examined the structure of the gene in DNA from 26 patients with acute leukemia and from 23 normal individuals. We have found that the T-cell antigen receptor gene has undergone somatic rearrangement in 14 of 14 patients with the phenotypic diagnosis of T-cell acute lymphoblastic leukemia. In this group of patients, similar patterns of rearrangement appear to occur in different patients. This finding suggests that there is either a limited repertoire of possible rearrangements or an association between the development of leukemia and specific patterns of rearrangement. DNA from 6 patients with acute myeloblastic leukemia, 6 patients with non-B, non-T acute lymphoblastic leukemia, and 23 nonleukemic individuals showed no rearrangement or polymorphism. One case of T-cell acute lymphoblastic leukemia, however, showed rearrangement of both the T-cell receptor beta chain and the constant region of the immunoglobulin gene. Studies with mixtures of DNAs from leukemic bone marrow cells and cultured skin fibroblasts, as well as with remission and relapse marrow DNAs from the same patients, indicate that this technique can detect 1% leukemic cells in a mixed population. In addition, DNA from the marrow of a patient in relapse contains a similar rearrangement to that found in the marrow sample taken at the time of diagnosis, which suggests that the original clone of leukemic cells was responsible for relapse. Our results indicate that assessment of rearrangement of the T-cell antigen receptor gene will be valuable in the diagnosis and management of leukemia and can be used to evaluate clonality in T-cell neoplasia.

Evaluation of the S-Plus IV

An evaluation of a Coulter Counter Model S-Plus IV hematology analyzer was undertaken at Memorial Sloan-Kettering Cancer Center to assess performance characteristics and to determine accuracy in analyzing both normal and clinical specimens. Special emphasis was placed on the platelet parameter. Precision, linearity, and carryover were found to be well within the manufacturer's specifications. A total of 222 patient samples were analyzed in the routine laboratory and on the Model S-Plus IV. Coefficients of correlation of 0.99 or higher were obtained for white blood cell count (WBC), red blood cell count (RBC), hemoglobin (Hgb), platelets (Plt), except mean cell volume (MCV) (r = 0.93). Results from 99 selected normal samples were compared with those from manual reference methods. Coefficients of correlation of 0.98 or higher were obtained for WBC, RBC, and Hgb. For MCV, the correlation coefficient was 0.85 and for Plt, 0.89 was obtained. The lower coefficient of correlation for these two parameters may be a function of the imprecision of the manual reference methods. In a previous study with an original Model S-Plus, the Plt parameter occasionally exhibited spuriously high counts. With the advent of third-generation S-Plus instruments, represented by the Model S-Plus IV, the possibility of reporting aberrant Plt values virtually has been eliminated. Data from the current study verify this. However, 93% of the flagged Plt results proved to be accurate, checking slides on these introduced inefficiencies in the laboratory.

Some observations on the zinc metabolism of the rabbit lens

Rabbits' lenses contain about 100 mumol kg-1 wet wt (145 mumol kg-1 water) of zinc. This metal appears to be quite uniformly distributed throughout the organ and more than 90% is firmly incorporated into the tissue so as not to be readily exchangeable. The concentration of Zn in the aqueous and vitreous humors is about 10(-5) M (one-fourth the concentration in the blood serum). Lenses incubated in vitro can accumulate Zn from solutions containing this concentration of the metal. This process is concentration-dependent and is increased following damage produced by metabolic inhibitors. The process probably involves diffusion and is increased in the presence of a low external calcium concentration and the Ca ionophore A 23187. Amino acids which are known to bind zinc did not influence its accumulation by the lens, with the exception of cystine which increased it. Accumulated Zn (using 65Zn as a tracer) was able to leave the lens, but this process was quite slow and was reduced by the presence of lanthanum and low Ca concentrations. It is suggested that Ca and Zn may share common binding sites in the tissue, and they could be utilizing the same channels to cross the cell membrane.

Absorption of 4,4'-methylenebis [2-chloroaniline] by human skin

A system was developed to measure percutaneous absorption of water-insoluble environmental agents into human skin. Percutaneous absorption of 4,4'-[14C]methylenebis [2-chloroaniline] (MBOCA) was measured during dry contact exposure of MBOCA with organ cultures of neonatal foreskin. Time-dependent exposures, autoradiographs, and thin-layer chromatography indicated that MBOCA was rapidly and progressively absorbed and passed through the skin without being metabolized. The transepithelial penetration of MBOCA was temperature dependent. Under certain conditions, the stratum corneum contained more MBOCA than other layers in the skin, which suggested that the stratum corneum may not be the main barrier for percutaneous absorption of MBOCA. An assessment of risk confirmed that skin exposure is a cause for concern.

Kinetics of tissue distribution and elimination of 4,4'-methylene bis(2-chloroaniline) in rats

The tissue distribution kinetics and elimination of 4,4'-methylene bis(2-chloroaniline) (MBOCA) in rats was studied after a single dose of [14C]MBOCA (0.49 mg/kg body weight, i.v.). The highest concentrations of radioactivity were in the small intestine, liver, adipose, lung, kidney, skin, and adrenals. For most tissues, a rapid decrease in radioactivity was followed by a slower decrease except for the small intestine, adipose and skin which demonstrated transient increases. Subcellular distribution in liver at 1 h showed radioactivity in all cell fractions. Although very lipophilic, [14C]MBOCA was completely eliminated within 48 h with the major route via the feces (73.4%).