Localization of glycoconjugates recognized by the HNK-1 antibody in mouse and chick embryos during early neural development

The monoclonal antibody HNK-1 recognizes a carbohydrate epitope present on a host of glycoconjugates which include the glycoproteins neural cell adhesion molecules (N-CAM) myelin-associated glycoprotein and ependymins, and two glycolipids. Other antibodies, including NC-1, L2 and IgM paraproteins from neuropathy patients share similar binding specificity to the same or related sulfated glucuronyl-containing antigen (SGA). To further investigate its possible significance in early development, the distribution of SGA was studied in the head region of early developing chick (S13-S18) and mouse (E8.5-E11.5) embryos by immunocytochemistry. A striking species difference was found in the apparent distribution of immunodetectable SGA. In chick, migrating neural crest cells and their related cell types were heavily stained by HNK-1; whereas no stain was detectable on mouse neural crest cells at comparable stages, except perhaps in a restricted area adjacent to the otic placode and immediately adjacent to the neural tube. Within the developing CNS, the distribution of SGA was similar in both species. It was first expressed on neuroepithelial cells prior to axonal outgrowth, and was distributed in a continuous zone along the entire lateral walls of the early neural tube. Little or no SGA was detectable along most of the floor and roof plates. SGA appeared during this same period in the lateral basal lamina and within the adjacent mesenchyme and nearby cells. SGA was particularly evident on neuroepithelial endfeet at this stage. Early developing longitudinal axons were subsequently found to grow in association with the endfeet of SGA-positive neuroepithelial cells. These findings, in conjunction with previous studies, suggest that SGA is associated as a marker, and perhaps functionally, with the organization of early neuronal settling and axonal growth patterns within the developing vertebrate CNS.     

Enhancement of swine progenitor chimerism in mixed swine/human bone marrow cultures with swine cytokines.

OBJECTIVE: The induction of transplantation tolerance across xenogeneic barriers by bone marrow transplantation holds great promise, but engraftment of xenogeneic stem cells has been difficult to achieve. Part of this difficulty is due to species-specific differences in regulatory cytokines and elements of the stromal microenvironment, which we studied here. MATERIALS AND METHODS: We developed a system where fresh bone marrow cells from swine and human are cultured on human bone marrow stroma in order to study these limiting factors in a clinically relevant species combination. RESULTS: We report here the ability of recombinant swine interleukin (IL)-3 and c-kit ligand (KL) to specifically enhance swine hematopoietic chimerism in this system. In the absence of exogenous swine cytokines, there were about half as many swine progenitors as human progenitors at 1, 2, and 4 weeks of culture. When used alone, swine IL-3 led to a notable but transient increase in the relative ratio of swine progenitors, while addition of swine KL increased the ratio of swine progenitors only modestly and only at later time points. In contrast, when swine IL-3 and KL were added together, there was a two- to fourfold increase in the ratio of swine to human progenitors at all times tested. CONCLUSION: These data demonstrate that both swine IL-3 and KL are needed for prolonged enhancement of swine progenitor chimerism under these conditions, and suggest that the species specificity of either one or both of these cytokines may represent an important barrier to prolonged engraftment of swine bone marrow in humans.     

Failure to awaken after general anaesthesia secondary to paradoxical venous embolus

A patient is presented who failed to regain consciousness after an apparently uneventful nine-hour revision of a total hip replacement. There were no clinically important haemodynamic changes during the operation, and oxygen saturation, capnography and acid base balance were normal throughout. Postop CT of the head showed a large left MCA infarct with midline shift. At autopsy, the patient was found to have a previously unsuspected patent foramen ovale, and a venous embolus in the left internal carotid artery, which probably had originated from the periprostatic venous plexus with a large infarct in the distribution of the left anterior and middle cerebral arteries. The authors conclude that massive paradoxical venous emboli can occur during surgery with minimal haemodynamic changes.     

Intravenous digital subtraction renal angiography: use in screening for renovascular hypertension

Intravenous digital subtraction renal angiography (DSRA) has been compared with conventional angiography only in small, selected series of hypertensive patients. The authors prospectively examined with intravenous DSRA 94 patients at increased risk for renovascular hypertension and compared these studies with conventional angiography. A stenosis of at least one main renal artery was identified with intravenous DSRA in 22 patients and confirmed in 20 patients. No significant stenoses were seen with conventional angiography in any of the 64 patients in whom lesions were not seen with intravenous DSRA. Since inadequate DSRA studies were considered positive for renal artery stenosis, the sensitivity of intravenous DSRA was 100% (25 of 25); specificity, 93% (64 of 69); positive predictive value, 83% (25 of 30); and negative predictive value, 100% (64 of 64). The authors conclude that intravenous DSRA is a sensitive test for identifying stenosis of the main renal arteries and is appropriate to use as a screening test among patients at increased risk for renovascular hypertension.     

Review of iliopsoas anatomy and pathology

The iliopsoas compartment acts as a conduit for the spread of disease within the body. Knowledge of its anatomy facilitates the early diagnosis of some potentially fatal lesions.