Neuroimaging in Pineal Tumors

BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.     

Autologous whole plasma fibrin gel. Intraoperative procurement.

Fibrin glue is a relatively recent addition to the armamentarium of hemostatic agents for surgical use. Its efficacy has been repeatedly demonstrated in almost all surgical disciplines and subspecialties. Its use in the United States has been limited because of the risk of viral transmission associated with the use of human plasma. Previous authors have described techniques that limit this risk, but they are frequently impractical, expensive, or cumbersome. We describe the use of patients' own fresh plasma to make fibrin gel at the operative field. It provided hemostasis at least as good as that from heterologous plasma glue in 40 cardiac surgical patients. Autologous whole plasma fibrin gel is inexpensive and safe and eliminates the risk of viral transmission associated with glue derived from heterologous donor plasma.     

Validity of the beck depression inventory,hospital anxiety and depression scale,SCL-90, and hamilton depression rating scale as screening instruments for depression in stroke patients

Most instruments used to assess poststroke depression have never been specifically validated in stroke patients. This study evaluated the depression screening abilities of three questionnaires and one observer-rated scale in 202 consecutive patients 1 month after they experienced their first-ever ischemic stroke. At their respective optimum cutoff values, the sensitivity of the self-rated scales varied between 80% and 90%, while the specificity was about 60%. For the observer-rated scale (Hamilton Depression Rating Scale), sensitivity was 78.1%, and specificity was 74.6%. The instruments clearly performed better in men than in women. Despite this difference, it was concluded that all scales were acceptable screening instruments for poststroke depression.     

Muscle lactate transport studied in sarcolemmal giant vesicles: dependence on fibre type and age.

Lactate transport was studied in sarcolemmal giant vesicles obtained from rat or rabbit skeletal muscle. With this technique it is possible to obtain quantitative information on sarcolemmal transport characteristics. In equilibrium exchange experiments with 10, 30 and 60 mM lactate, vesicles from 'red' rat muscles had a 50% higher lactate transport capacity than vesicles from 'white' muscles. Giant vesicles made from rabbit red muscles had a 39% higher lactate transport capacity than vesicles from white muscles. These differences probably reflect a different number of lactate transporters, whereas the lactate affinity in red and white muscles are identical. Lactate transport capacity decreased with age. Sarcolemmal giant vesicles made from 22-month-old rats had a 28% lower transport capacity than vesicles from 2-month old rats. In absolute terms, the initial exchange flux with 30 mM lactate was 92 and 127 pmol cm-2 sec-1 for old and young rats, respectively. In supplementary studies in which microelectrode measurements were made in single mouse muscle fibers, it was shown that the cellular acidification rate due to lactate incubation, was 38% lower in fibres from 18-month old mice than in fibres from 2-month old mice.     

Expression, distribution and ultrastructural localization of the synapse-organizing molecule agrin in the mature avian retina

At the vertebrate neuromuscular junction the extracellular matrix molecule agrin is responsible for the formation, maintenance and regeneration of most if not all postsynaptic specializations. Several agrin isoforms are generated by alternative splicing which differ in their function and which are all expressed in the CNS. To analyse the role of agrin in the CNS, we investigated the expression and ultrastructural localization of agrin in the posthatched chick retina. In situ hybridization revealed the presence of agrin mRNA in all cellular layers of the mature retina, indicating that most if not all major retinal cell types synthesize agrin. Pan-specific as well as isoform-specific antiagrin antisera stained the optic fibre layer and the outer plexiform layer. However, only the pan-specific antiserum additionally stained the inner limiting membrane. Immunoelectron microscopy showed that in the optic fibre layer agrin was associated with ganglion cell axons and that at least part of this agrin corresponds to a neuronal isoform of agrin. In the outer plexiform layer, agrin was localized in the cleft between the photoreceptor terminals and the invaginating horizontal and bipolar cell dendrites. In the synapse-containing inner plexiform layer both antisera revealed punctate immunoreactivity. This staining corresponded to agrin concentrated in the synaptic cleft of conventional synapses as determined by preembedding immunoelectron microscopy. Agrin is thus concentrated at mature interneuronal synapses as it is at the neuromuscular junction, consistent with a role of agrin during formation and/or maintenance of synapses in the CNS.     

Corneal ulcers and the use of topical fluoroquinolones.

PURPOSE: To determine whether the widespread use of topical fluoroquinolones has changed the spectrum of ulcerative keratitis, and to determine how it has affected practice patterns in the treatment of corneal ulcers. METHODS: We retrospectively reviewed the charts of 48 consecutive patients with infectious corneal ulcers from 7/1/91 to 12/31/91 and 47 consecutive patients from 7/1/94 to 12/31/94. Patients were treated with intensive topical antibiotics (either standard fortified antibiotics or topical fluoroquinolones) at a frequency of at least every hour while awake. Some patients were admitted to the hospital, and some underwent scraping for smears and cultures. RESULTS: Ulcers which were seen in 1994 appear to have been more severe than those seen in 1991 as judged by the presence of more ulcers associated with hypopyons, (P< 0.05) but not with regard to the size of the infiltrate or epithelial defect. More ulcers in 1994 were treated on an outpatient basis (P< 0.02) and fewer ulcers were scraped and cultured than in 1991 (P< 0.001). Culture results from the 1991 and 1994 groups were similar. The most frequently isolated organisms were coagulase-negative Staphylococcus, Pseudomonas, Staphylococcus aureus, and Streptococcus spp. CONCLUSION: The spectrum of ulcerative keratitis at a tertiary referral center may be showing a trend towards more severe ulcers, but the causative agents responsible for the infection are unchanged.