A modified technique of delayed primary closure using a povidone iodine wick: Influence on wound healing in an experimental model

We report a modified technique of delayed primary wound closure using a wound wick. A rodent model was used to determine its influence on healing. After loose primary closure of two paravertebral incisions on the dorsum of male rats, a 10 cm length of ribbon gauze, soaked in either saline or 1% povidone-iodine, was inserted into the right sided wound. Wicks were soaked daily with the same solution until removal on the third post-operative day. The inclusion of a wick soaked in saline had an early transient effect on healing. A more prolonged impairment of healing was demonstrated in povidone-iodine wicked wounds and their respective controls. These data suggest that povidone-iodine impaired healing not only in the wicked wound, but also inhibited healing in the adjacent unwicked wound which was not directly exposed to the antiseptic. The observed delay in healing in povidone-iodine wicked wounds must however be balanced against its beneficial effect on wound infection rates. We suggest that further evaluation of this method of closure in contaminated wounds is warranted.     

Dynamic gadolinium-enhanced echo-planar MR imaging of the liver: Effect of pulse sequence and dose on enhancement

To develop guidelines for clinical magnetic resonance imaging of the liver, the authors undertook an animal study to investigate the effect of dose and pulse sequence on liver signal intensity in gadopentetate dimeglumine—enhanced echo-planar imaging. Serial imaging of the liver was performed in anesthetized rats after intravenous administration of five different doses (0.01, 0.05, 0.1, 0.2, and 0.5 mmol/kg) of contrast agent, with six different pulse sequences. The results show that gadopentetate dimeglumine—enhanced echo-planar images obtained during the perfusion phase can yield either positive (due to increased T1 relaxation rates) or negative (due to susceptibility-induced increased T2 relaxation rates) liver enhancement depending on choice of pulse sequence and dose. At the current clinically recommended dose of 0.1 mmol/kg, maximal liver signal enhancement was seen with a T1-weighted inversion-recovery sequence, while maximal liver signal diminution was seen with a T2*-weighted gradient-echo sequence. The authors conclude that gadopentetate dimeglumine—enhanced echo-planar imaging can provide T1, T2, and T2* contrast that may be exploited for both lesion detection and lesion characterization.     

Ethanol's effects on auditory thresholds and reaction times during the acquisition of chronic ethanol self-administration in baboons

Baboons were trained to ingest ethanol at successively higher ethanol concentrations using oral self-administration techniques. Concurrently, animal psychophysical procedures were employed to determine auditory thresholds and reaction times daily. Maximal consumption of ethanol occurred at concentrations of 6-8% (w/v). During the initial period of ethanol self-administration, both auditory reaction times and auditory thresholds became elevated as animals consumed larger amounts of ethanol. For both the threshold and reaction time measures, the degree of elevation was correlated with the amount of ethanol consumed. These correlations decreased, however, with continued ethanol consumption. The elevations in sensory and motor function recovered to near-baseline levels when ethanol was no longer available.     

Dynamic spin-echo MRI of liver cancer using Gadolinium-DTPA: animal investigation

An animal model of liver cancer was used to demonstrate that with a fast MRI technique, Gadolinium-DTPA increases tumor-liver contrast. A spin-echo pulse sequence with short repetition (TR) and echo-delay (TE) times (TR 250/TE 15/Excitations 1) has a scan time of 0.6 min, which allows early dynamic postcontrast infusion imaging. This is necessary to capture peak compartmental differences when an extracellular contrast agent such as Gadolinium-DTPA is used. This short TR/short TE pulse sequence also increases T1-dependent tissue contrast over the traditional (inversion recovery or spin echo) T1-weighted pulse sequences. Our studies suggest a significant potential for improved detection of liver metastases with Gadolinium-DTPA-enhanced liver MRI.     

Gaucher disease: abdominal MR imaging findings in 46 patients.

Abdominal magnetic resonance imaging findings were reviewed in 46 patients with Gaucher disease. All patients had hepatosplenomegaly at the time of initial imaging. Splenic nodules were present in 14 patients (30%) and varied in signal intensity. These nodules were isointense on T1-weighted and hypointense on T2-weighted images. Splenic infarcts were seen in 15 patients (33%), and four of these patients (9%) also had subcapsular fluid collections. Both nodules and infarcts were present in the spleen in four patients (9%). Pathologic correlation was performed with specimens from two patients who underwent partial splenectomy. Focal areas of abnormal signal intensity were noted in the liver in nine patients (20%). They were either stellate or segmental, and may represent fibrotic septa with ischemic changes associated with aggregates of Gaucher cells. No changes were noted in the kidneys or abdominal lymph nodes.     

Nephrotic syndrome and renal failure associated with a novel glycolipid storage disorder

A 57-year-old Caucasian male presented with severe nephrotic syndrome and diffuse organomegaly; he subsequently developed renal failure and died. Intracellular, crystalloid material was identified by light and electron microscopy in bone marrow, liver, spleen, mesenteric lymph nodes, and kidneys. Tissue extraction analysis identified the material as glucocerebroside and its immediate precursor, ceramide lactoside. Although Gaucher's disease cannot be completely excluded, glycolipid profiles do not conform to those of known storage disorders. Additionally, electron-microscopic studies indicate that the structural features of the glycolipid deposits are different from those of previously described storage diseases. These findings suggest a unique crystalloid deposition as the probable cause of a multisystem process, which was associated with renal insufficiency and death.     

Shape of the myopic eye as seen with high-resolution magnetic resonance imaging.

We have obtained multislice magnetic resonance (MR) images of the eye and calculated ocular dimensions along the three cardinal axes: antero-posterior (A-P), equatorial, and vertical. We found no difference in the shape of hyperopic (average refractive error: +3.72 D) and emmetropic eyes, both of which had an equatorial diameter longer than the A-P and vertical diameters. Myopic eyes (average refractive error: -6.54 D) were larger than hyperopic eyes, and most had the same spheroelliptical shape as that of the emmetropic and hyperopic eyes. The results suggest that during myopic progression an overall enlargement or a radial volume expansion has occurred.