Markers of periodontal disease susceptibility and activity--a review.

There appears to be sufficient evidence to indicate that traditional clinical parameters are unable to determine active disease sites in periodontitis and predict future periodontal breakdown. This paper attempts to review some of the recent research aimed at developing laboratory markers of disease susceptibility and activity. A wide variety of studies have involved specific plaque bacteria and their products, host cells and their products, and products of soft and hard tissue injury.

Hepatobiliary MR imaging: first human experience with MnDPDP.

The first human MR imaging results for the hepatobiliary contrast agent manganese(II)N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (MnDPDP) are reported. MnDPDP is a paramagnetic contrast agent specific for hepatobiliary imaging. An imaging study was performed to investigate the presence of contrast enhancement or facilitated visualization of normal structures.

Preclinical evaluation of MnDPDP: new paramagnetic hepatobiliary contrast agent for MR imaging.

Manganese(II)-N,N'-dipyridoxylethylenediamine-N,N'-diacetate-5,5'-bis (phosphate) (MnDPDP) is a paramagnetic complex designed for use as a hepatobiliary agent. The T1 relaxivity of MnDPDP (2.8 [mmol/L]-1.

Iron oxide-enhanced MR imaging of the liver and spleen: review of the first 5 years.

Superparamagnetic iron oxide (SPIO) particles are a potent new class of MR contrast agents affording improved detection of hepatic and splenic neoplasms. In this report we review the development of this agent through preclinical studies and early clinical results at Massachusetts General Hospital during a 5-year investigation. SPIO particles are sequestered by normal phagocytic Kupffer cells of the reticuloendothelial system (RES) but are not retained in tumor tissue.

Detection of hepatic metastases: comparison of contrast-enhanced CT, unenhanced MR imaging, and iron oxide-enhanced MR imaging.

Diagnostic accuracy of contrast-enhanced CT, unenhanced MR imaging, and MR images enhanced with superparamagnetic iron oxide was evaluated in 10 patients with histologically proved hepatic metastases. First, diagnostic performance of the imaging technique with respect to the ability of radiologists to recognize the presence or absence of a metastasis was measured by using receiver-operating-characteristic (ROC) analysis of single images. Second, the total number of lesions (N = 108) detected by "complete" CT and MR examinations was counted.

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Localization of P-31 MR signal with use of superparamagnetic iron oxide particles.

Volume localization of magnetic resonance signals was achieved by using the regional susceptibility differences produced by superparamagnetic iron oxide particles. In vitro experiments demonstrated a direct linear relationship between the concentration of particulate iron and phosphorus-31 chemical shift or line broadening. In vivo experiments indicated that an intravenous dose of 5-10 mg of iron per kilogram of body weight suppressed P-31 signal from normal liver in healthy rats.

Hepatic tumors: quantitative tissue characterization with MR imaging.

To determine which quantitative methods of image analysis are most suitable for the differential diagnosis of benign and malignant hepatic lesions, the authors analyzed magnetic resonance images obtained at 0.6 T in 42 patients with proved hepatic cavernous hemangioma and 63 patients with various hepatic malignancies. The lesion-liver signal-intensity ratio for images obtained with a repetition time of 2,350 msec and echo time of 180 msec was most helpful in distinguishing hemangiomas from cancer (area under the receiving operator characteristic curve [ROC] = 0.

First clinical trial of a new superparamagnetic iron oxide for use as an oral gastrointestinal contrast agent in MR imaging.

The authors report the results of preclinical testing and initial clinical application of a superparamagnetic iron oxide specifically prepared as a contrast agent for magnetic resonance (MR) imaging of the gastrointestinal tract. MR imaging was performed at 0.6 and 1.

A case-control study of Nocardia mastitis in Ontario dairy herds.

A case-control study was conducted to identify milking hygiene and udder therapy factors associated with a diagnosis of Nocardia mastitis in dairy herds from which milk samples are submitted to the Ontario Ministry of Agriculture and Food, Veterinary Laboratory Services, Guelph laboratory. The data were collected by telephone interview from 31 case and 31 control herds.After analytical control for confounders, blanket dry cow therapy and a dry cow antibiotic product were associated with a diagnosis of Nocardia mastitis in a herd, whereas another dry cow antibiotic product had a sparing effect.

Evaluation of Monte Carlo generation of continuous asymmetric distributions.

Reliable methods for generating pseudo-random numbers from specific distributions are increasingly important in all branches of applied mathematics. In Monte Carlo studies, generating random variables from specific continuous probability distributions, whether symmetric or asymmetric is a fundamental consideration. A composite uniform U(0,1) generator algorithm is described and statistically tested.

Evaluation of Monte Carlo generation of long-tailed symmetric and contaminated symmetric distributions.

Generating random variables from a specific distribution, whether symmetric or asymmetric, is a concern of investigators involved in Monte Carlo studies. Of particular interest to those concerned with robustness is the generation of contaminated symmetric distributions such as those used in the Princeton Robustness Study. A reliable composite uniform U(0,1) generator is described and algorithms for transforming U(0,1) to symmetric long-tailed and contaminated symmetric distributions are given.

Hepatic cirrhosis and hepatitis: MR imaging enhanced with superparamagnetic iron oxide.

Superparamagnetic iron oxide was applied as a reticuloendothelial contrast agent in the diagnosis of cirrhosis and hepatitis in seven patients. Three patients had compensated cirrhosis, and four had active hepatitis. T1- and T2-weighted spin-echo magnetic resonance images were obtained before and 1 hour after the administration of iron oxide.

Clinical application of superparamagnetic iron oxide to MR imaging of tissue perfusion in vascular liver tumors.

Previous studies of AMI-25, a particulate iron oxide magnetic resonance contrast agent, imaged liver tumors 1 or more hours after injection, in the retention phase after complete clearance of AMI-25 from the circulation. In the present study, imaging was performed in the distribution phase, during the first 12 minutes after injection while contrast agent remain in circulation, and these images were compared with those obtained in the retention phase. Nineteen patients with cancer were studied, including 15 imaged during the distribution phase.

Detection of hepatic metastases with MR imaging: spin-echo vs phase-contrast pulse sequences at 0.6 T.

The purpose of this study was to compare the sensitivity of T1-weighted and T2-weighted spin-echo (SE) pulse sequences with T2-weighted phase-contrast (PC) imaging techniques for the detection of hepatic metastases. Pulse-sequences performance was evaluated in 52 consecutive patients with 88 hepatic metastases who underwent MR imaging at 0.6 T.

Forty-millisecond MR imaging of the abdomen at 2.0 T.

The ability of an ultrafast magnetic resonance (MR) imaging technique to provide abdominal MR images free of motion artifacts was studied. Individual T2-weighted transverse MR images were acquired in as little as 40 msec on a whole-body system operating at 2.0 T.

Protection against tobacco mosaic virus in transgenic plants that express tobacco mosaic virus antisense RNA.

Transgenic tobacco plants that express RNA sequences complementary to the tobacco mosaic virus (TMV) coat protein (CP) coding sequence with or without the tRNA-like structure at the 3' end of the TMV RNA were produced. Progeny of self-pollinated plants were challenged with TMV to determine their resistance to infection. Plants that expressed RNA sequences complementary to the CP coding region and the 3' untranslated region, including the tRNA-like sequences, were protected from infection by TMV at low levels of inoculum.

Superparamagnetic iron oxide-enhanced MR imaging: pulse sequence optimization for detection of liver cancer.

The effects of magnetic resonance (MR) pulse sequences and timing parameters on tumor-liver contrast were studied in an animal model of metastatic liver cancer. Six spin-echo (SE), three inversion-recovery (IR), and four gradient-echo (GRE) sequences were evaluated at 0.6 T before and after injection of super-paramagnetic iron oxide.

The nucleotide sequence of a soybean mosaic virus coat protein-coding region and its expression in Escherichia coli, Agrobacterium tumefaciens and tobacco callus.

A DNA complementary to the 3'-terminal 1168 nucleotides of the genome of the N strain of soybean mosaic virus (SMV) has been cloned and sequenced. cDNA sequence and coat protein analyses indicate that the SMV coat protein-coding region is at the 3' end of the genome, and that the coat protein is processed from a larger protein. The coat protein-coding sequence is predicted to be 795 nucleotides in length, encoding a protein of 265 amino acids with a calculated Mr of 29,857.

Experimental lymph node metastases: enhanced detection with MR lymphography.

Magnetic resonance (MR) lymphography with superparamagnetic iron oxide (AMI-25) as a contrast agent was developed in an animal model with tumor-bearing lymph nodes. After interstitial administration of 20 mumol of iron per kilogram of body weight into the footpads of rats, the T2 of popliteal and paraaortic lymph nodes decreased from 67 msec +/- 8.2 to 9.

Short TI inversion-recovery imaging of the liver: pulse-sequence optimization and comparison with spin-echo imaging.

Magnitude-reconstructed short inversion-time (TI) inversion-recovery (IR) sequences have the advantage of reducing the signal of fat while providing additive T1 and T2 contrast. A double-echo short TI IR sequence was implemented to offer different degrees of T1- and T2-dependent image contrast. In 50 consecutive patients with proved liver tumors (30 metastases, 13 hemangiomas, seven other primary liver tumors), images obtained with a double-echo IR sequence at a repetition time (TR) of 1,500 msec, echo time (TE) of 30 and 60 msec, and TI of 80 msec (TR/TE/TI = 1,500/30, 60/80) were compared with those obtained with spin-echo (SE) sequences at a TR of 275 msec and a TE of 14 msec (TR/TE = 275/14) and 2,350/60, 120, 180.