Infusible Extracellular Matrix Biomaterial Promotes Vascular Integrity and Modulates the Inflammatory Response in Acute Traumatic Brain Injury

Traumatic brain injury (TBI) affects millions of people each year and, in many cases, results in long-term disabilities. Once a TBI has occurred, there is a significant breakdown of the blood-brain barrier resulting in increased vascular permeability and progression of the injury. In this study, the use of an infusible extracellular matrix-derived biomaterial (iECM) for its ability to reduce vascular permeability and modulate gene expression in the injured brain is investigated. First, the pharmacokinetics of iECM administration in a mouse model of TBI is characterized, and the robust accumulation of iECM at the site of injury is demonstrated. Next, it is shown that iECM administration after injury can reduce the extravasation of molecules into the brain, and in vitro, iECM increases trans-endothelial electrical resistance across a monolayer of TNFα-stimulated endothelial cells. In gene expression analysis of brain tissue, iECM induces changes that are indicative of downregulation of the proinflammatory response 1-day post-injury/treatment and neuroprotection at 5 days post-injury/treatment. Therefore, iECM shows potential as a treatment for TBI.

Injectable Myocardial Matrix Hydrogel Mitigates Negative Left Ventricular Remodeling in a Chronic Myocardial Infarction Model

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Myocardial matrix hydrogel preserves LV volumes and apical wall thickening in a chronic MI model.

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Myocardial matrix hydrogel trends toward reduced fibrosis.

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In vivo differential gene expression analysis shows the matrix modulates cardiac muscle contraction, metabolism, fibrosis, and the inflammatory/immune response in a chronic MI model.

A first-in-man clinical study on a myocardial-derived decellularized extracellular matrix hydrogel suggested the potential for efficacy in chronic myocardial infarction (MI) patients. However, little is understood about the mechanism of action in chronic MI. In this study, the authors investigated the efficacy and mechanism by which the myocardial matrix hydrogel can mitigate negative left ventricular (LV) remodeling in a rat chronic MI model. Assessment of cardiac function via magnetic resonance imaging demonstrated preservation of LV volumes and apical wall thickening. Differential gene expression analyses showed the matrix is able to prevent further negative LV remodeling in the chronic MI model through modulation of the immune response, down-regulation of pathways involved in heart failure progression and fibrosis, and up-regulation of genes important for cardiac muscle contraction.

Solvation phenomena of a tetrapeptide in water/trifluoroethanol and water/ethanol mixtures: a diffusion NMR, intermolecular NOE, and molecular dynamics study

Solvation of a tetrapeptide, NAc-Ser-Phe-Val-Gly-OMe (1), in water and in water/alcohol mixtures with 2,2,2-trifluoroethanol (TFE)/water or ethanol (ETH)/water has been studied by diffusion NMR and intermolecular NOE measurements. The experimental results were compared with those obtained from detailed Molecular Dynamics (MD) calculations. Independently, all three methods revealed preferential solvation on the surface of the peptide by TFE in the water/TFE mixtures, but not by ETH in the water/ETH mixtures. The MD calculations show that the TFE concentration coating the peptide is higher than that in the bulk, while for ethanol, the concentration is nearly equal to that in the bulk. Calculated site-specific preferential solvation data between TFE, ETH, and water with the different peptide groups have been compared with the NMR data and shown to be in general agreement with the experimental facts.

Isoniazid preventive therapy in human immunodeficiency virus-infected persons. Long-term effect on development of tuberculosis and survival

BACKGROUND

Although the short-term benefit of isoniazid prophylaxis in patients coinfected with human immunodeficiency virus (HIV) and tuberculosis has been shown, long-term benefits are unknown.

METHODS

Historical cohort study in an acquired immunodeficiency syndrome unit at a tertiary referral hospital. A sample of 121 HIV-infected patients with positive results on a purified protein derivative test were followed up for development of active tuberculosis and survival. Patients who received isoniazid prophylaxis were compared with patients who did not receive prophylaxis.

RESULTS

Of the 121 patients examined, 29 (24%) completed a 9- to 12-month course of isoniazid prophylaxis (median follow-up, 89 months), and 92 (76%) did not receive the drug (median follow-up, 60 months). Active tuberculosis developed in 46 patients (38%). The incidence of tuberculosis was higher among patients with no prophylaxis (9.4 per 100 patient-years) than among patients with isoniazid prophylaxis (1.6 per 100 patient-years) (P = .006). Risk for development of tuberculosis was associated with the absence of isoniazid prophylaxis (relative risk [RR], 6.55; 95% confidence interval [CI], 2.02-21.19). Death during the period of study was more frequent in patients who did not receive isoniazid (50/92 or 54%) than in patients who received isoniazid (7/29 or 24%) (P = .008). Median survival was more than 111 months in patients who received isoniazid compared with 75 months in patients who did not receive isoniazid (P < .001). In a proportional hazards analysis, the development of tuberculosis (RR, 1.88; 95% CI, 1.09-3.27), the absence of isoniazid prophylaxis (RR, 2.68; 95% CI, 1.16-6.17), and a CD4+ cell count lower than 0.20 x 10(9)/L (RR, 3.03; 95% CI, 1.39-6.61) were independently associated with death. Patients who received isoniazid had a longer survival after stratifying for the CD4+ cell count.

CONCLUSIONS

Preventive therapy with isoniazid confers long-term protection against tuberculosis and significantly increases survival in patients dually infected with HIV and Mycobacterium tuberculosis.

Intraoperative mitomycin in primary pterygium excision. A prospective, randomized trial

PURPOSE

Conjunctival autograft transplantation and postoperative mitomycin therapy are two adjuvant treatment methods shown to lessen the high pterygium recurrence rate seen with simple excision alone. The authors conducted a prospective, randomized study comparing these two techniques with a relatively new treatment method using intraoperative mitomycin application.

METHODS

Fifty patients with 56 primary pterygia were randomized to 1 of 3 treatment groups: conjunctival autograft (group 1), postoperative mitomycin 0.2 mg/ml four times a day x 7 days (group 2), and intraoperative mitomycin 0.4 mg/ml x 3 minutes (group 3). The mean follow-up time was 16 months (range, 6 to 28 months).

RESULTS

Recurrences developed in 4 (22.2%) of 18 eyes in group 1, 4 (21.1%) of 19 eyes in group 2, and 2 (10.5%) of 19 eyes in group 3. Complications developed in two, patients from group 2, scleral thinning managed successfully with a scleral patch graft, and epithelial toxicity that resolved on discontinuation of mitomycin on postoperative day 6. There were no complications in the other two groups.

CONCLUSIONS

Intraoperative mitomycin is a simple and effective alternative to postoperative mitomycin therapy, showing the lowest recurrence rate in their series with no toxicity during the study period. If the decision is made to use adjunctive mitomycin, the authors recommend intraoperative application over postoperative administration.

Infections caused by erythromycin-resistant Streptococcus pneumoniae: incidence, risk factors, and response to therapy in a prospective study

To evaluate the incidence and the significance of resistance to erythromycin among clinical isolates of Streptococcus pneumoniae, we identified and prospectively followed all hospitalized patients in a 27-month period who had the organism isolated from any clinical sample. Patients who had an infection caused by pneumococci resistant to erythromycin (minimum inhibitory concentration, > 1 microgram/mL) were compared to those with infections caused by erythromycin-susceptible organisms. The incidence of erythromycin resistance among pneumococci doubled over the study period (from 7.6% in 1988 to 15.2% in 1992). Most strains (94%) showed resistance to multiple antibiotics, including other macrolides. By multivariate analysis, an age of < 5 years and nosocomial acquisition of the infection were independent risk factors for erythromycin resistance. Among patients with pneumococcal pneumonia caused by erythromycin-resistant organisms, 9 patients treated with third-generation cephalosporins were cured, while therapy with erythromycin failed for 2 of the 6 patients to whom it was administered. The rapid and significant increase of erythromycin resistance among clinical isolates of S. pneumoniae points to the need for routine surveillance of pneumococcal resistance.

Listeriosis in patients infected with human immunodeficiency virus

Although resistance to Listeria monocytogenes infection requires intact T cell-mediated immunity, only 20 patients with human immunodeficiency virus (HIV) infection and listeriosis (including one patient described herein) have been reported to date. Listeriosis developed before AIDS in five cases. Syndromes included meningitis in nine cases, bacteremia in nine, brain abscess in one, and endocarditis in one. Eighteen patients were treated with ampicillin, penicillin, or amoxicillin with or without aminoglycosides. Clinical and microbiologic responses were obtained in one patient with bacteremia treated with vancomycin and in one patient with meningitis treated with trimethoprim-sulfamethoxazole. Three of the nine patients with meningitis died, as did the patient with brain abscess. All nine patients with bacteremia and the patient with endocarditis survived. No case of relapse was documented. L. monocytogenes, although uncommon, should be considered in the differential diagnosis of febrile illness, meningitis, and brain abscess in patients with HIV infection.