Efficacy of portable X-ray in identifying retained suture needles in ophthalmologic cases.

AIMS: To evaluate the role and efficacy of portable X-ray in reliably identifying retained suture needles in ophthalmologic surgical cases. METHODS: Ophthalmologic 10-0 nylon suture needles were placed into 10 of 20 porcine eyes positioned within the orbit of a human skull. Portable, plain film radiographs were taken of all eyes with a C-arm fluoroscopy machine. The films were reviewed by six ophthalmologists and six radiologists who were blinded to the presence or absence of needles, as well as the number of needles used in the protocol. The sensitivity and specificity of identifying retained suture needles by plain film radiographs were then analysed based on the results of the physicians' interpretations of the films. RESULTS: The overall sensitivity and specificity for physicians reviewing radiographs with suspected intraoperative suture needles were 54 and 77%, respectively. When looking separately at radiologists reviewing the films, the sensitivity was 57% and the specificity was 87%. Ophthalmologists reviewing the films identified retained needles less reliably with a sensitivity of 51% and a specificity of 67%. CONCLUSIONS: Significant controversy exists regarding the reliability and utility of plain film radiography in identifying intraocular foreign bodies. This study demonstrates that the use of plain film radiographs to rule-out the presence of an intraocular surgical needle is neither a sensitive nor specific imaging modality.

Subcellular and subsynaptic localization of presynaptic and postsynaptic kainate receptor subunits in the monkey striatum.

The localization and functions of kainate receptors (KARs) in the CNS are still poorly known. In the striatum, GluR6/7 and KA2 immunoreactivity is expressed presynaptically in a subpopulation of glutamatergic terminals and postsynaptically in dendrites and spines. The goal of this study was to further characterize the subcellular and subsynaptic localization of kainate receptor subunits in the monkey striatum. Immunoperoxidase data reveal that the relative abundance of GluR6/7- and KA2-immunoreactive terminals is homogeneous throughout the striatum irrespective of the differential degree of striatal degeneration in Huntington's disease. Pre-embedding and post-embedding immunogold data indicate that >70% of the presynaptic or postsynaptic GluR6/7 and KA2 labeling is expressed intracellularly. In material stained with the post-embedding immunogold method, approximately one-third of plasma membrane-bound gold particles labeling in axon terminals and spines is associated with asymmetric synapses, thereby representing synaptic kainate receptor subunits. On the other hand, >60% of the plasma-membrane bound labeling is extrasynaptic. Both GluR6/7 and KA2 labeling in glutamatergic terminals often occurs in clusters of gold particles along the membrane of large vesicular organelles located at various distances from the presynaptic grid. Anterograde labeling from the primary motor cortex or the centromedian thalamic nucleus indicate that both corticostriatal and thalamostriatal terminals express presynaptic GluR6/7 and KA2 immunoreactivity in the postcommissural putamen. In conclusion, these data demonstrate that kainate receptors in the striatum display a pattern of subcellular distribution different from other ionotropic glutamate receptor subtypes, but consistent with their metabotropic-like functions recently shown in the hippocampus.

Ionotropic and metabotropic GABA and glutamate receptors in primate basal ganglia.

The functions of glutamate and GABA in the CNS are mediated by ionotropic and metabotropic, G protein-coupled, receptors. Both receptor families are widely expressed in basal ganglia structures in primates and nonprimates. The recent development of highly specific antibodies and/or cDNA probes allowed the better characterization of the cellular localization of various GABA and glutamate receptor subtypes in the primate basal ganglia. Furthermore, the use of high resolution immunogold techniques at the electron microscopic level led to major breakthroughs in our understanding of the subsynaptic and subcellular localization of these receptors in primates. In this review, we will provide a detailed account of the current knowledge of the localization of these receptors in the basal ganglia of humans and monkeys.

Anatomy of the dopamine system in the basal ganglia.

The dopaminergic nigropallidal and nigrosubthalamic projections control the activity of the globus pallidus and subthalamic nucleus neurons in both normal and pathological conditions. Intrastriatal dopaminergic neurons increase substantially in animal models of Parkinson's disease. They contain GABA, display the ultrastructural features of interneurons and form axo-axonic synapses with putative cortical-like glutamatergic boutons. The local dendritic release of dopamine by neurons in the substantia nigra pars compacta and ventral tegmental also influences basal ganglia functions. Thus, the long-term belief that the effects of dopamine in the basal ganglia were solely mediated through the nigrostriatal system must be changed to take into account extrastriatal dopaminergic projections and intrastriatal dopaminergic neurons.

CART peptide-immunoreactive neurones in the nucleus accumbens in monkeys: ultrastructural analysis, colocalization studies, and synaptic interactions with dopaminergic afferents.

Cocaine- and amphetamine-regulated transcript (CART) is a novel mRNA whose level of expression was found to be increased in the striatum after acute administration of psychomotor stimulants in rats. To define better the potential role of CART peptides in behavioural and physiologic changes induced by psychomotor stimulants, we analyzed the distribution, ultrastructural features, synaptic connectivity, and transmitter content of CART peptide-immunoreactive neurones in the nucleus accumbens in monkeys. Medium-sized CART peptide-immunoreactive neurones within a rich plexus of labelled varicosities were found mostly in the medial division of the shell of the nucleus accumbens in monkeys. At the electron microscope level, CART peptide immunoreactivity was exclusively associated with neuronal structures that included perikarya, dendrites, spines as well as nerve terminals packed with electron-lucent and dense-core vesicles. Most CART peptide-containing somata displayed the ultrastructural features of striatal output neurones. The majority of labelled terminals formed symmetric axodendritic synapses and displayed gamma-aminobutyric acid (GABA) immunoreactivity. CART peptide-immunoreactive somata were not immunoreactive for parvalbumin and somatostatin, two markers of striatal interneurones, nor for calbindin D-28k, a marker of a subpopulation of projection neurones. In double-immunostained sections, CART peptide-immunoreactive dendrites were found to be contacted by tyrosine hydroxylase-positive terminals which displayed the ultrastructural features of dopamine-containing boutons. These findings strongly suggest that CART peptides may be a cotransmitter with GABA in a subpopulation of projection neurones in the monkey accumbens. Furthermore, the fact that CART peptide-immunoreactive neurones receive direct synaptic inputs from dopaminergic afferents and are particularly abundant in the caudomedial division of the shell of the nucleus accumbens suggest that CART peptides might be involved in neuronal and behavioural changes that underlie addiction to psychomotor stimulants and feeding in primates.

CO2 power-assisted hand-held syringe: better visualization during diagnostic and interventional angiography.

Recent technology has produced high-flow and large-lumen catheters as well as other angiographic accessories to enhance the visualization of the coronary arteries during diagnostic and percutaneous transluminal coronary angioplasty (PTCA) procedures. In spite of these technological advances, there are still many cases in which the quality of the coronary angiography could be significantly improved. This paper reports on a clinical evaluation of a hand-held power syringe. The syringe offers the ability to power inject contrast safely and effectively during routine angiograms as well as through guiding catheters with the balloon catheter present during PTCA. At the same time, control of the injection is equal to that associated with manual syringes.

Failure of Hancock xenograft valve: importance of valve position (4- to 9-year follow-up).

To evaluate long-term durability of Hancock valves, we reviewed our results in 107 hospital survivors (120 valves) who were operated on during 1974 through mid-1979. Mitral valve replacement was done in 63 patients, aortic valve replacement in 20, and mitral valve replacement combined with other procedures in 24. The 7-year survival was 84 +/- 4% (standard error of the mean) for 91 patients and 97 valves. During a follow-up of 590 patient-years, 15 (12 mitral and 3 aortic) of 120 valves at risk (87 mitral, 32 aortic, 1 tricuspid) were removed from 14 patients. Six valves (3 mitral and 3 aortic) were removed because of bacterial endocarditis. One mitral valve was removed because of thromboembolism. Eight mitral valves were removed because of valve structural failure, which occurred at a mean follow-up of 42 months. These valves showed extensive calcification, leaflet perforation, or cusp tear. Structural failure was unrelated to valve size, year of implantation, or valve shelf-life. Structural failure was not seen after aortic valve replacement. Results show that structural failure of the Hancock xenograft valve in the mitral position is related primarily to valve position. After aortic valve replacement, valve failure is predominantly due to endocarditis. Although medium-term (mean, 6-year) durability of this xenograft valve compares satisfactorily with prosthetic valves, its high failure rate in the mitral position indicates the necessity for improvement in valve mounting, design, and preservation.

Successful pregnancy in a woman with a left ventricular cardiac aneurysm. A case report.

Ventricular cardiac aneurysms associated with pregnancy are extremely rare. The effects of one on the other are not known. The pathophysiology of cardiac aneurysms as known in the nonpregnant state combined with the physiologic cardiovascular adjustments of pregnancy can be suspected of compromising the welfare of the pregnant patient. We recently treated a 21-year-old pregnant patient with a post-myocardial-infarction left ventricular cardiac aneurysm. The outcome was successful.

Gestational diabetes: diagnosis and management.

Pregnancy is a diabetogenic condition and approximately one per cent of suspected patients will develop an abnormal glucose tolerance test during pregnancy. Generally, the gestational diabetic tends to be heavier, older, and multiparous. The diagnosis can be made from the patient's family history, previous obstetrical history, or from clinical tests such as urine glucose, fasting blood sugar, and glucose tolerance tests. The management of the patient includes patient evaluation, diet, evaluation of the fetus, and selecting the time of terminating the pregnancy. With correct care and treatment, the patient can deliver a normal and healthy infant.