Neutrophil-Mediated Immunopathology and Matrix Metalloproteinases in Central Nervous System - Tuberculosis

Tuberculosis (TB) remains one of the leading infectious killers in the world, infecting approximately a quarter of the world’s population with the causative organism Mycobacterium tuberculosis (M. tb). Central nervous system tuberculosis (CNS-TB) is the most severe form of TB, with high mortality and residual neurological sequelae even with effective TB treatment. In CNS-TB, recruited neutrophils infiltrate into the brain to carry out its antimicrobial functions of degranulation, phagocytosis and NETosis. However, neutrophils also mediate inflammation, tissue destruction and immunopathology in the CNS. Neutrophils release key mediators including matrix metalloproteinase (MMPs) which degrade brain extracellular matrix (ECM), tumor necrosis factor (TNF)-α which may drive inflammation, reactive oxygen species (ROS) that drive cellular necrosis and neutrophil extracellular traps (NETs), interacting with platelets to form thrombi that may lead to ischemic stroke. Host-directed therapies (HDTs) targeting these key mediators are potentially exciting, but currently remain of unproven effectiveness. This article reviews the key role of neutrophils and neutrophil-derived mediators in driving CNS-TB immunopathology.

Intra-arterial urokinase versus surgery for acute peripheral arterial occlusion

The outcomes of intra-arterial urokinase versus surgery for acute peripheral arterial occlusion (PAO) were compared. Patients at a university hospital who had received intraarterial urokinase for PAO were identified by computer and pair-matched on the basis of comorbidities, age, sex, and site of occlusion to computer-selected patients who had undergone surgery. Only patients with category I or II ischemia were considered. The study period for the urokinase group was February 1995 through January 1996, and the period for the surgery group was June 1993 through January 1996. Twenty-eight patients in each group met the selection criteria. Patients who had received urokinase had a significantly shorter median length of stay (8.5 days) than patients in the surgery group (13 days) and significantly fewer infectious complications (2 versus 10). No differences in amputation rates, total hospital costs, or mortality rates were detected. Patients who received intra-arterial urokinase for PAO had a shorter length of stay in the hospital and fewer infectious complications than those who underwent surgery.

Aortoscopy: a guidance system for endoluminal aortic surgery

PURPOSE

The aim of this project was to evaluate the feasibility of aortoscopy for guidance of endoluminal aortic procedures and to determine whether aortoscopy has advantages over fluoroscopy in a pig model.

METHODS

To establish feasibility aortoscopic guidance was used for making endoluminal aortic measurements, cannulating small arteries for arteriograpy, and placing intraaortic stents and grafts in 11 pigs. To compare aortoscopy and fluoroscopy measurements were made and stents were placed by a surgeon using only aortoscopic guidance in 10 pigs and by an interventional radiologist using only fluoroscopic guidance in 10 pigs. Postmortem dissections were performed to determine measurement and device placement accuracy.

RESULTS

In the feasibility study aortoscopic measurements differed from postmortem measurements by a mean distance (+/- SD) of 1.2 +/- 0.2 mm. Stents and grafts were placed a mean of 2.3 +/- 1.9 mm distal to the most inferior renal artery with no stent covering an orifice. All attempts at cannulating spinal arteries greater than 2 mm in diameter were successful. In the comparison of aortoscopic and fluoroscopic guidance, fluoroscopic measurements differed from postmortem measurements by 2.6 +/- 2.4 mm (p = 0.223). Stents placed with aortoscopic guidance were 1.1 +/- 1.3 mm distal to the most inferior renal artery, whereas stents placed with fluoroscopic guidance were 3.4 +/- 2.5 mm distal to the most inferior renal artery (p = 0.019).

CONCLUSIONS

These results demonstrate that aortoscopy is a useful guidance system for endoluminal aortic procedures and may have advantages over fluoroscopy alone.

Echogenicity of fetal lung: relation to fetal age and maturity

Reports of echogenicity of the fetal lung as it relates to maturity of that organ are scant and at variance. A study was undertaken to determine if any correlation between fetal age and/or lung maturity and echogenicity could be determined in a clinical setting. Studies were performed with either linear array or mechanical sector real-time devices. Echogenicity of the fetal lung was compared with that of the fetal liver in the same longitudinal (parasagittal or coronal) sonogram. Lung echogenicity was judged to be hypodense, isodense, slightly hyperdense, or markedly hyperdense as compared with the liver texture. One hundred eighty-five studies were evaluated; of these, some 37 patients also underwent amniocentesis for determination of lecithin/sphingomyelin ratios (L/S) and presence of phosphatidyl glycerol (PG). Linear regression analyses were performed to determine if lung echogenicity would serve as an indicator of fetal maturity. No clinically applicable relation was established between fetal lung echogenicity and gestational age, L/S, or presence of PG in amniotic fluid with current methodology. The possibility persists that tissue characterization techniques may find application in such an investigation.

Embolization of a sciatic artery aneurysm an alternative to surgery: a case report

An elderly woman was admitted with a 2-day history of pain, numbness and coolness of the left lower limb. The left foot on examination was cool and blue with no palpable pulse nor motor or sensory function. An arteriogram demonstrated a dilated persistent sciatic artery. The superficial femoral artery was hypoplastic and there was poor visualization of the distal circulation. At surgery an occluded popliteal artery was found. Attempts to open the occluded artery were unsuccessful and a left fibulectomy and fasciotomy was performed and the patient started on intravenous heparin. The patient's condition deteriorated and on the 4th hospital day an above-knee amputation was undertaken. The patient made an uneventful recovery and was subsequently discharged. At follow-up a month later the aneurysm was still patent and strongly pulsatile. She was readmitted to the hospital and the aneurysm was successfully embolized.

Preoperative lymph node evaluation in prostatic cancer patients who are surgical candidates: the role of lymphangiography and computerized tomography scanning with directed fine needle aspiration

A total of 53 consecutive patients who were candidates for surgical treatment of prostatic cancer underwent preoperative evaluation of the lymph node status by computerized tomography scanning and/or lymphangiography combined with skinny needle aspiration biopsy of any abnormal lymph nodes. In 7 of 14 patients (50 per cent) ultimately found to have stage D1 disease lymphatic metastases were confirmed histologically with needle biopsy alone, thus, obviating the need for pelvic lymph node dissection. Over-all sensitivity, specificity and accuracy rates were 50, 100 and 91.4 per cent, respectively, for computerized tomography scanning with biopsy and 53.8, 100 and 84.1 per cent, respectively, for lymphangiography with biopsy. Computerized tomography scanning and lymphangiography with aspiration biopsy are cost-effective means to identify approximately 50 per cent of the patients who ultimately have lymphatic metastases.

Mediastinal hemorrhage: an evaluation of radiographic manifestations

Eleven common radiographic signs of mediastinal hemorrhage were evaluated by two observers for the following three patient groups: normal subjects, patients with mediastinal hemorrhage and no arterial injury, and patients with major thoracic arterial injury. Supine chest radiographs were studied in all cases. Four major conclusions can be made based upon these findings. M/C ratio (mediastinal width to chest width), tracheal deviation, left hemothorax, paraspinal line widening, and aorto-pulmonary window opacification do not reliably separate these three groups of patients. The diagnosis of mediastinal hemorrhage may be made if the aortic contour is abnormal or if one of the following signs is positive: abnormal mediastinal width, apical cap, widening of the right paratracheal stripe, or deviation of the nasogastric tube. If either the right paratracheal stripe is widened or the nasogastric tube is deviated, the diagnosis of aortic rupture can be made with a 24% probability; if both signs are negative, there is a 98% probability that aortic rupture is absent. Due to interobserver variation, there is good agreement between observers for the following four signs only: transverse mediastinal width, tracheal deviation, nasogastric tube deviation, and right paratracheal stripe widening.

The medullary pyramid index: an objective assessment of prominence in renal transplant rejection

Prominence of the medullary pyramids at sonography has been considered a sign of renal transplant rejection. A search of the literature reveals no previously published objective assessment of this phenomenon. Medullary pyramids of 67 normal kidneys, 53 nonrejecting transplanted kidneys, and 71 transplanted kidneys in rejection were measured. The area of the pyramid was related to the thickness of the overlying renal cortex by a "medullary pyramid index" (MPI): MPI (formula; see text) The median MPI was 4.17 for normal kidneys, 6.0 for nonrejecting transplanted kidneys, and 7.50 for transplanted kidneys in rejection. The results are significantly different (P = 0.0001) for all possible pairs. Overlap between rejection and nonrejection distributions is, however, considerable, rendering the discriminatory value of an individual observation quite low (0.69). Prominence of the medullary pyramids is therefore of very limited predictive value in the determination of transplant rejection in an individual patient.