Intraventricular neurocytoma, a recently recognized pathological entity: report of two cases and review of the literature.

Neurocytoma has only recently been recognized as a distinct pathological entity. Previously a rare tumor, it is now being recognized with increasing frequency. It typically presents in an intraventricular location in young adults. Many neurocytomas were originally diagnosed by light microscopy as oligodendrogliomas. More recently they have been shown to have ultrastructural and immunohistochemical features of neuronal differentiation. This paper presents two cases of intraventricular neurocytomas and reviews the recent literature.     

Association of dietary and biochemical measures of vitamin K with quantitative ultrasound of the heel in men and women

Introduction Low vitamin K nutritional status is associated with increased fracture risk but is inconsistently related to bone mineral density (BMD), suggesting that vitamin K may affect components of bone strength not measured by BMD, such as microarchitecture. Quantitative ultrasound (QUS) may assess trabecular orientation, providing information on the mechanical properties of bone and may serve as a potential alternative to BMD for gaining insight to the relation between vitamin K and bone strength. We therefore examined the association of vitamin K nutritional status measured in several different ways with QUS in men and women who participated in the Framingham Osteoporosis Study. Methods From 1996 to 2001, broadband ultrasound attenuation (BUA) and speed of sound (SOS) of the calcaneus (heel) were measured in 583 men and 768 women (mean age 59 years). Vitamin K nutritional status was assessed between 1995 and 1998 by three separate measures: plasma phylloquinone concentration, serum percent undercarboxylated osteocalcin (%ucOC) and dietary vitamin K intake. Multiple linear regression analyses were used to calculate regression coefficients in order to evaluate the associations between both measures of QUS and each measure of vitamin K nutritional status. Regression analyses were conducted separately for subgroups of participants defined by gender, menopause status and current use of estrogen replacement medication. Results Among the men, plasma phylloquinone concentration was positively associated with both BUA (P<0.01) and SOS (P=0.02) of the heel. Neither serum %ucOC nor dietary vitamin K intake, however, was associated with QUS measures. Among women, none of the three measures of vitamin K nutritional status were associated with either BUA or SOS, regardless of menopause status or use of estrogen. Although QUS is associated with vitamin K nutritional status in men, the observed relation was not consistent among subgroups of participants. Conclusion These findings suggest that QUS may not be the best method for elucidating the role of vitamin K on the skeleton. From the Framingham Heart Study of the National Heart Lung and Blood Institute of the National Institutes of Health and Boston University School of Medicine, Framingham, Massachusetts, USA.     

Homozygous deletion mutations in the plectin gene (PLEC1) in patients with epidermolysis bullosa simplex associated with late-onset muscular dystrophy

In a distinct autosomal recessive variant of epidermolysis bullosa, EB- MD, life-long skin blistering is associated with late-onset muscular dystrophy of unknown etiology. Electron microscopy of these patients' skin suggests that tissue separation occurs intracellularly at the level of the hemidesmosomal inner plaque, which contains plectin, a high molecular weight cytoskeletal associated protein, also expressed in the sarcolemma of the muscle. In this study, we report two patients with EB-MD, each with a homozygous deletion mutation in the plectin gene, PLEC1. In the first case, the proband and her similarly affected sister had a homozygous 9 bp deletion mutation, designated as 2719de19, which resulted in elimination of three amino acids, QEA, in a sequence of 23 amino acids entirely conserved between the mouse and human sequences. The proband in the second family demonstrated a single nucleotide deletion at position 5866, designated as 5866delC, which resulted in frameshift and a premature termination codon for translation 16 bp downstream from the site of deletion. The absence of plectin in the hemidesmosomes, as reflected by negative immunofluorescence with an anti-plectin antibody (HD-1), associated with fragility of basal keratinocytes, implicates plectin as critical for binding of intermediate keratin filament network to hemidesmosomal complexes. The function of plectin as a putative attachment protein also in the muscle would explain the clinical phenotype consisting of cutaneous fragility and muscular dystrophy in EB-MD.      

Non-solar ultraviolet radiation and the risk of basal and squamous cell skin cancer.

A case-control study of non-melanocytic skin cancer was conducted among men in the province of Alberta, Canada. Two hundred and twenty-six cases of basal cell carcinoma (BCC), 180 cases of squamous cell carcinoma (SCC) and 406 age-matched controls provided information concerning skin pigmentation, occupational history, recreational activity, exposure to sunlight and sources of non-solar ultraviolet radiation (NSUVR) and other potential risk factors. Our analyses show no evidence of elevated risk for BCC or SCC among subjects exposed to various types of NSUVR. This is in opposition to studies of melanoma that have shown elevated risks for exposure to fluorescent lighting, sunlamps and sunbeds.     

Interventricular neurocytoma: radiologic features and review of the literature.

Intraventricular neurocytoma (IN), a recently recognized, benign cerebral tumor of young adults, can be confused with oligodendroglioma and other neoplasms. The authors compared the radiologic features of six pathologically confirmed cases of IN with those of 26 previously reported cases. The presenting symptoms were headache (62%), raised intracranial pressure (41%), and seizures (12%). Radiologically, the tumor frequently demonstrated a characteristic attachment to the septum pellicidum and confinement to the lateral and third ventricles. Calcification, which is common in IN and an important diagnostic feature, was seen to best advantage on computed tomographic (CT) scans. The results indicate that IN can be suggested radiologically on the basis of its CT appearance and should be included in the pathologic differential diagnosis of intraventricular tumors.     

Effects of graded experimental compression on slow and fast axonal transport in rabbit vagus nerve

Effects of compression at low pressures on slow and fast axonal transport was investigated in rabbit vagus nerve. Proteins in the sensory fibres were radiolabelled by injection of [3H]leucine or [35S]methionine into the nodose ganglion. A small compression chamber and/or ligatures were applied around the cervical part of the vagus nerve for 8 h, at an appropriate time for the subsequent analysis of the effects of compression on both slow and fast transport of radiolabelled proteins. In normal nerves there were two waves of slowly transported proteins with rates of about 12-15 and 25-30 mm/day, respectively. SDS-polyacrylamide gel electrophoresis was used and confirmed that the main proteins which accumulated proximal to the ligatures had a molecular weight of 54 000-56 000. Neither compression of the nerve at 20 mm Hg nor sham-compression induced any statistically significant accumulation of slowly transported proteins at the site of compression. A higher pressure, i.e. 30 mm Hg, induced a marked but incomplete accumulation of slowly transported proteins. Fast transport was partially inhibited in some, but not all, nerves, when 20 mm Hg was applied for 8 h, in contrast to the lack of effect found previously with the same pressure applied for only 2 h. Despite these slight differences, the results indicate that both slow and fast transport are impaired by low pressure levels of around 20-30 mm Hg, which are comparable with those found in human compression neuropathies. The impaired provision of cytoskeletal elements to the distal axon may be of significance in the pathophysiology of nerve entrapment syndromes.     

Synthesis and antiviral activity of (E)-5-(2-bromovinyl)uracil and (E)-5-(2-bromovinyl)uridine

(E)-5-(2-Bromovinyl)uracil (BVU) and (E)-5-(2-bromovinyl)uridine (BVRU) were synthesized starting from 5-formyluracil via (E)-5-(2-carboxyvinyl)uracil or starting from 5-iodouridine via (E)-5-(2-carbomethoxyvinyl)uridine and (E)-5-(2-carboxyvinyl)uridine, respectively. Depending on the choice of the cell system, BVU and BVRU exhibited a marked activity against herpes simplex virus type 1 (HSV-1) in vitro. Although BVU and BVRU were less potent than the reference compound (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), their antiviral activity spectrum was remarkably similar to that of BVDU. The latter findings suggest that BVU and BVRU are metabolically converted to BVDU or a phosphorylated product thereof. In vivo, BVU protected mice against a lethal disseminated HSV-1 infection.     

A simple cytologic method for predicting the malignant potential of intraocular melanoma

The malignant potential of 100 intraocular uveal melanomas was assessed by determining the mean of the ten largest nucleoli (MTLN). On a single standard microslide from each tumor, the maximum diameter of the ten largest nucleoli was measured using a manually operated micrometer. For comparison, three additional histopathologic parameters were determined for each case: Standard deviation of nucleolar area (SDNA), Callender cell type (CT), and largest tumor dimension (LTD). Of these four parameters, MTLN and SDNA were most highly correlated with death from ocular tumor. Furthermore, repeat measurement of all 100 cases revealed a level of reproducibility for MTLN similar to that for SDNA. Of greatest importance, the micrometer technique employed in this study has substantial cost and labor advantage over the computer-controlled system required to measure SDNA.     

Surgical education: neck dissection.

Neck dissection is a valuable procedure for treating metastatic cancers of the head and neck. Radical neck dissection remains the standard for cervical metastasis. Because of the morbidity associated with such a treatment, more conservative approaches are being adopted. The authors describe how they do a neck dissection and review the issues that currently surround the choice of treatment.