The clinical and pathological features of siblings with infantile neuroaxonal dystrophy--early neurological, radiological, neuroelectrophysiological and neuropathological characteristics]

The clinical and pathological features of siblings with infantile neuroaxonal dystrophy were reported. Early clinical symptoms were marked hypotonia in legs, mental regression and poor vision. Laboratory data were normal except for the mild elevation of GOT and LDH in serum and cerebrospinal fluid. MRI showed progressive atrophy of cerebellar vermis and brainstem. EEG showed a progressive increase in the amount and amplitude of the fast activities over the age of 3 years. Auditory brainstem response (ABR) showed progressive worsening with no response by 2 years and 6 months. Somatosensory evoked potentials (SEP) showed no cortical response by 4 years. Nerve conduction velocity (NCV) of both motor and sensory nerves was within normal limits. Pathologically, spheroid bodies were found in the axons of central and peripheral nerves, remarkably in brainstem and dorsal column. MRI, ABR and SEP findings were clinically useful, suggestive of the degeneration of brainstem.     

Steroidogenic acute regulatory protein (StAR) retains activity in the absence of its mitochondrial import sequence: Implications for the mechanism of StAR action

Steroidogenic acute regulatory protein (StAR) plays a critical role in steroid hormone biosynthesis, presumably by facilitating the delivery of cholesterol to P450scc in the inner mitochondrial membranes. StAR is synthesized as a 37-kDa preprotein that is processed to a 30-kDa mature form by cleavage of an N-terminal mitochondrial import sequence. To identify structural features required for StAR biological activity, we mutated the human StAR cDNA, including the deletion of N- and C-terminal sequences, and examined the ability of the mutants to promote steroidogenesis and enter the mitochondria of transfected COS-1 cells. Deletion of up to 62 residues from the N terminus (N-62) did not significantly affect steroidogenesis-enhancing activity. The N-terminal deletion mutants were associated with mitochondria-enriched fractions, but import and processing were progressively impaired with increasing length of the deletion. Immunogold electron microscopy and in vitro import assays showed that the active N-62 mutant was not imported into the mitochondria. Removal of the 28 C-terminal amino acids (C-28) inactivated StAR. Deletion of the C-terminal 10 amino acids (C-10) reduced steroidogenic activity by 53%, while truncation of the last 4 amino acids had no effect. The C-28 mutant StAR was not efficiently imported into mitochondria or processed, whereas some of the C-10 mutant was processed, indicating that import had occurred. We conclude that in the COS-1 cell system used, StAR does not need to enter into mitochondria to stimulate steroidogenesis and that residues in the C terminus are essential for steroidogenesis-enhancing activity. These findings imply that StAR acts via C-terminal domains on the outside of the mitochondria.     

Cloning, expression, and characterization of cDNAs encoding Arabidopsis thaliana squalene synthase.

We have isolated and characterized two overlapping cDNA clones for Arabidopsis thaliana squalene synthase. Their nucleotide sequences contained an open reading frame for a 410-amino acid polypeptide (calculated molecular mass, 47 kDa). The deduced amino acid sequence of the Arabidopsis polypeptide was significantly homologous (42-44% identical) to the sequences of known squalene synthases of several species, from yeast to man, but it was much less homologous to that of tomato phytoene synthase. To express the Arabidopsis enzyme in Escherichia coli, the entire coding region was subcloned into an expression vector. A cell-free extract of E. coli transformed with the recombinant plasmid, in the presence of NADPH and Mg2+, efficiently converted [14C]farnesyl diphosphate into squalene. On the other hand, in the absence of NADPH and the presence of Mn2+, the cell-free extract formed dehydrosqualene as a secondary product. Another E. coli extract expressing mouse squalene synthase showed the same activity as the Arabidopsis enzyme. Therefore, both the structure and reaction mechanism of squalene synthases are markedly conserved in taxonomically remote eukaryotes.     

Role of Na+ in α-aminoisobutyric acid uptake by membrane vesicles from mouse fibroblasts transformed by simian virus 40

The uptake of alpha-amino[(3)H]isobutyric acid (AIB) was studied in membrane vesicles from mouse fibroblasts transformed by simian virus 40 to examine the features of the Na(+)-stimulated and Na(+)-dependent AIB transport process. The simultaneous addition of NaCl and AIB to these vesicles produced a transient accumulation, or "overshoot," of amino acid 3-4 times the equilibrium value. Both the initial rate of uptake and the rate of fall of intravesicular AIB after maximal accumulation were sensitive to the temperature of incubation.The overshoot of AIB uptake was enhanced with Na(+) salts of highly permeant lipophilic anions, such as SCN(-) and NO(3) (-), and was decreased by the addition of SO(4) (2-), a relatively impermeant ion. Gramicidin D, which enhances the membrane conductance of Na(+) electrogenically, decreased the overshoot, while a potassium diffusion potential, induced by valinomycin (in K(+)-preloaded membrane vesicles), produced a Na(+)-dependent overshoot of AIB uptake.When vesicles were preincubated with both Na(+) and AIB, followed by the generation of an interior negative membrane potential (by the addition of SCN(-)), an overshoot of AIB uptake resulted. However, this did not occur in the absence of Na(+). It is concluded that, apart from its role in the generation of a transmembrane electrochemical potential, Na(+) is essential for the overshoot of AIB uptake.     

Relationships between blood rheology and age, body mass index, blood cell count, fibrinogen, and lipids in healthy subjects

We investigated the relationships between blood rheology assessed by microchannel method and the various hemorheologic factors in healthy subjects. One hundred seventy-six healthy volunteers (90 men and 86 women, mean age; 32.9+/-11.3 years) were participated in this study. Body weight, body mass index, red blood cell count, hematocrit, hemoglobin, white blood cell count, and platelet count, plasma fibrinogen, and fasting serum lipid and lipoprotein concentrations were measured. In order to assess blood rheology, blood passage time was determined by a microchannel method (Micro Channel Array Flow Analyzer). Age, body mass index, red blood cell count, hematocrit, hemoglobin, white blood cell count, total cholesterol, low-density lipoprotein cholesterol, and triglyceride were positively correlated with blood passage time in all subjects, respectively (p<0.01) and high-density lipoprotein cholesterol was inversely correlated with blood passage time (p<0.01). However, platelet count, and fibrinogen were not correlated with blood passage time. The present study showed that increased age, body mass index, red blood cell count, white blood cell count, total cholesterol, low-density lipoprotein cholesterol, and triglyceride and decreased high-density lipoprotein cholesterol were associated with impaired blood rheology measured by microchannel method in healthy subjects, suggesting that aging, obesity, erythrocytosis, leukocytosis, and dyslipidemia may be related to hemorheological disorders. This microchannel method may be useful to study blood rheology which may be associated with various risk factors of cardiovascular disorders.     

Cytologic diagnosis of endosalpingiosis with pregnant women presenting in peritoneal fluid: a case report

The cytologic appearance of endosalpingiosis in peritoneal fluid cytology smears has not been extensively described. We report a case of endosalpingiosis in a 29-year-old pregnant female who presented with peritoneal fluid. Dense papillary epithelial clusters with indistinct ciliated cells were found in the Papanicolaou-stained smears. However, long and delicate cilia were obvious in papillary cluster with scanning electron microscopy. Cell nuclei were oval, with finely dispersed chromatin and uniform nuclear membrane. Peritoneal fluid cytology with these findings may be helpful to suggest the probable preoperative diagnosis of endosalpingiosis or benign glandular inclusions involving the pelvic peritoneum.