Direct observation in vitro of how neuroblasts migrate: medulla and cochleovestibular ganglion of the chick embryo

The hypothesis that neuroblasts migrate in the nervous system by a locomotory process was tested experimentally. An in vitro preparation permitted direct observation of postmitotic cells migrating from the rhombic lip of the medulla and the anlage of the cochleovestibular ganglion. Cell locomotion was not seen. Instead migration was produced by elongation of a leading process, followed by translocation of the nucleus (perikaryal translocation). On the basis of comparisons with previous observations in situ, we propose that this represents a common mode of migration in the developing nervous system. Cell clusters were explanted from the rhombic lip at the developmental stage when they migrate from the ventricular zone to the acoustico-vestibular anlage in the medulla. Cells from the cochleovestibular ganglion were explanted after migration from the otocyst, but before ganglionic differentiation. Each neuroblast's migration route was formed by an elongating leading process ending in a growth cone. The growth cone attached to other cells and processes or ended freely on an acellular substrate. Nonneuronal cells usually migrated as has been described for fibroblasts, yet with some of the features of perikaryal translocation, but some nonneuronal precursor cells may migrate the way neuroblasts do. Neuroblasts did not migrate preferentially on the processes of nonneuronal cells, although the reverse could be observed. In fact a variety of interactions between migratory cells, neuronal and nonneuronal, were observed. The advantage of the experimental system described here is that one can observe cells migrating spontaneously at the times in development when they normally do so, while preserving the cellular populations present in situ.     

Detection of mucus glycoconjugates in human conjunctiva by using the lectin colloidal gold technique in TEM. I. A quantitative study in normal subjects

We applied a specific cytochemical reaction to characterize the glycoconjugates produced by goblet and non-goblet epithelial cells of normal human conjunctiva. For this purpose we utilized the lectins, proteins of vegetal origin, which are extremely sensitive in binding glycosidic residues. In particular, we used WGA, PNA, SBA and ConA conjugated with colloidal gold as ultrastructural marker for Transmission Electron Microscopy. This technique allowed us also to perform a quantitative analysis, by counting colloidal gold particles present on mucus granules. In this way we analyzed the content both of goblet and non-goblet epithelial cells. In the former, WGA, PNA, SBA and ConA receptors, here reported in decreasing density, were present. In the latter WGA was always positive, SBA and PNA sometimes were negative, ConA was always negative. We speculate the different contribution to mucus production by these two sources may be important in evaluating tear film stability alterations occurring in those diseases in which non-goblet epithelial cell vesicles increase.     

A review of lacrimal drainage surgery

The advent of improved silicone intubation sets, increased understanding of lacrimal and nasal anatomy and physiology, and refinements in surgical instrumentation and technique have led to higher success rates in lacrimal surgery. Recent clinical studies, combined with new techniques in canalicular reconstruction, have helped identify which patients will benefit from surgical intervention and which techniques are indicated. Fortunately, this has greatly reduced the number of CDCRs necessary.     

Diamine oxidase as a marker of intestinal integrity in acute appendicitis

In the operative treatment of appendicitis the so called negative appendectomy is an important issue because of its increased morbidity. From the hypothesis that the intestinal diamine oxidase activity is a suitable marker of mucosal integrity, the distribution pattern of the enzyme in appendices histologically classified as inflamed or not inflamed was studied. Histologically apparent inflammation of the appendix was connected with a significant reduction of diamine oxidase activity. The determination of this enzymic activity may be a simple and sensitive test for mucosal inflammation of the appendix even at a very early state. This could reduce the rate of negative appendectomies and influence thereby risk-cost-benefit calculations.     

The eye care profile and outcomes of multi-handicapped adults residing in Wayne County, Michigan group homes.

BACKGROUND: Patients with multi-handicaps present clinical challenges and are underserved. Central nervous system dysfunction and ocular disorders with this population are prevalent and well-documented. However, vision care outcomes data are limited and specific visual function recommendations to caregivers are rarely cited. METHODS: The charts of 110 multiply handicapped adults residing in 22 group homes in Wayne County. Michigan were retrospectively studied to identify ocular profiles and predictors of visual function. RESULTS: Sixty-five percent of the subjects were male and 80% were ages 26 to 55 years. There was no expressive language in 41%, and 37% were non-ambulatory. The median visual impairment level was moderate in both eyes (based on WHO). Significant associations between visual impairment level and subpopulations (such as seizure disorder, mental retardation without specific etiology, cerebral palsy, and Down syndrome) were identified. Successful spectacle wear statistically increased with higher refractive errors. Associations between cataract, nystagmus, and strabismus with particular subpopulations were significant (all P values < 0.0182). CONCLUSIONS: Clinicians who evaluate patients with multi-handicaps have few known predictors of treatment success. This study indicates that useful predictors of visual function can be made from refractive error, systemic conditions, and ocular diagnoses. No significant relationship was found with cognitive level and either vision impairment or spectacle use. The authors attribute successful implementation of recommendations to communication with group home caregivers.