The entorhinal cortex: an examination of cyto- and myeloarchitectonic organization in humans

The entorhinal cortex (ERC) has been implicated in the pathophysiology of Alzheimer's disease, schizophrenia and other disorders affecting cognitive functions. While powerful anatomical and histochemical methods (immunohistochemistry, in situ hybridization, etc.) may be applied (although with limitations) to postmortem human brain, each analysis should utilize a cytoarchitectonic approach to provide appropriate comparisons within the subdivisions of the ERC. Accordingly, we describe here the normal cyto- and myeloarchitecture of the human ERC as a prerequisite for the accompanying study of this region in schizophrenia. Our parcellation of this cortex differs from previous treatments in three ways. First, we adopted specific criteria of inclusion to define each subdivision of the region. Although distinctive ERC features are most prominent in the intermediate portion of this region, at least one of these features was considered the minimum necessary criterion to include adjacent tissue in the entorhinal area. Second, we used morphometric measurements (neuronal size and density as well as subdivisional volume and laminar thickness) to support our qualitative evaluation. Third, we have applied to the human ERC the conventional cytoarchitectonic nomenclature of the entorhinal cortex used previously in studies of non-human primates. This allows a more accurate extrapolation of the available numerous experimental anatomical, physiological and psychological data on this region to the human. As in the monkey, the five main subareas were recognized in the human (prorhinal, lateral, intermediate, sulcal and medial) but three required further subdivision (intermediate, sulcal and medial). The morphometric results obtained suggested a progression of the human entorhinal cortex from the peripheral to the central subareas, with the intermediate subarea (281) as the most complete entorhinal subdivision. Compared with non-human primates, the human ERC not only retains the basic periallocortical organization but also demonstrates further evolution. Taken together with available experimental data on the connectivity of this brain region, these results provide an anatomical basis for evaluating the ERC in human behavior.     

Surgical repair of urethral circumcision injuries

PURPOSE: The 2 types of urethral injury that can occur during circumcision are urethrocutaneous fistula and urethral distortion secondary to partial glans amputation. We report the surgical repair of these rare injuries. MATERIALS AND METHODS: In 8 patients urethrocutaneous fistulas located on the distal penile shaft or at the coronal margin were managed by splitting the glans and using a Mathieu style skin flap in 4 or vascularized penile skin flap in 4 to bridge the urethral defect. Three patients underwent repair of a hypospadiac deviated urethra secondary to partial glans amputation by 1 cm. of urethral mobilization and repositioning the meatus into a terminal position within the remaining glans tissue. RESULTS: The 8 patients with urethrocutaneous fistulas voided via a terminal meatus without fistula recurrence at a mean followup of 3.2 years (range 1 to 6). The 3 patients with partial glans amputation and urethral deviation repaired by short urethral advancement had functionally acceptable results, defined as a normal urinary stream, although 1 required meatal dilation postoperatively. CONCLUSIONS: The 2 types of urethral injuries that can occur during circumcision are a subcoronal urethrocutaneous fistula and scarred abnormal urethra from partial glans amputation. The urethrocutaneous fistula can be successfully repaired by splitting the glans and forming a neourethra from a vascularized pedicle flap of penile skin. The abnormal urethra after partial glans amputation is more difficult to repair but repositioning the urethra in a more cosmetic location has restored function.     

A cure for benign positional vertigo

Benign positional vertigo is a common clinical entity encountered in any dizzy clinic. It is easily diagnosed on the basis of historical information and a positive Dix-Hallpike position test. The available evidence suggests that this condition is due to involvement of the posterior semicircular canal. The pathophysiology of this condition can be explained theoretically on the basis of free-floating particles within the endolymph of the posterior semicircular canal that move under the influence of gravity with certain provocative positional changes. Based on this theoretical model, a variety of particle-repositioning manoeuvres have been developed that attempt to relocate the loose particles from the posterior semicircular canal to the utricular sac. If the particles are kept in the utricular sac for a period of 48 h by maintaining the patient in an upright position, the clinical symptoms are relieved in a high proportion of patients. If the manoeuvre is unsuccessful on a first attempt, or if the benign positional vertigo recurs at a later date, the condition can usually be relieved by a second manoeuvre. Bilateral benign positional vertigo can be treated by performing a manoeuvre on one side followed by a manoeuvre on the other side at a later date. On occasion, posterior canal benign positional vertigo is converted to horizontal canal benign positional vertigo, but this subsides readily within the 48-h post-manoeuvre period.     

Cyclophosphamide and low-dose prednisone therapy in patients with systemic sclerosis (scleroderma) with interstitial lung disease

Fourteen patients with systemic sclerosis (SSc, scleroderma) and interstitial lung disease were treated with oral cyclophosphamide (1-2 mg/kg/day) and low dose prednisone (< 10 mg/day). There was a significant improvement in FVC after 6 months compared to entry values (2.21 +/- 0.19 l vs. 2.03 +/- 0.15 l, p < 0.02). Improvement was maintained at 12 months (2.27 +/- 0.27 l, p < 0.05) and 18-24 months (2.60 +/- 0.28 l, p < 0.001). In 12 cases followed for 18-24 months, FVC was stable or improved. No significant improvement or decline was noted for the DLCO. Side effects included cytopenia (2), infection (1), and hemorrhagic cystitis (2), and one possible related malignancy. A controlled prospective trial of cyclophosphamide is warranted in patients with SSc and active interstitial lung disease.