Wide variations of plasma triglyceride concentrations in guinea pigs

Guinea pigs have varying plasma triglyceride concentrations ranging from 28 to 1392 mg/dl, with relatively uniform plasma cholesterol and phospholipid levels. To understand why the animals exhibit such wide variations of plasma triglyceride concentrations, we have explored the triglyceride hydrolyzing system by measuring tissue lipoprotein lipase activities and plasma activator for the enzyme. Lipoprotein lipase activities of epididymal adipose tissue of these animals were 759±117 (mean±SE) n moles FFA·min⁻¹·g wet tissue⁻¹, markedly low compared with those of rats. There were no relationships between plasma triglyceride concentrations and tissue lipase activities. Plasma activator for lipoprotein lipase was lacking in this animal. Guinea pigs with ascorbic acid deficiency for 2 weeks also showed marked variations of plasma triglyceride concentrations, without any changes in tissue lipoprotein lipase activities. Low adipose tissue lipoprotein lipase activities with deficient plasma activator for the enzyme suggest that the lipoprotein lipase-mediated triglyceride degradation could be impaired in this animal, and this may account for the marked variation of plasma triglyceride concentrations.     

Subcellular localization of prostaglandin endoperoxide H synthases-1 and -2 by immunoelectron microscopy

Prostaglandin endoperoxide H synthases-1 and -2 (PGHS-1 and -2) are the major targets of nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen. These enzymes catalyze the committed step in the formation of prostanoids from arachidonic acid. Although PGHS-1 and -2 are similar biochemically, a number of studies suggest that PGHS-1 and PGHS-2 function independently to form prostanoids that subserve different cellular functions. We have hypothesized that these isozymes may reside, at least in part, in different subcellular compartments and that their compartmentation may affect their access to arachidonic acid and serve to separate the functions of the enzymes. To obtain high resolution data on the subcellular locations of PGHS-1 and -2, we employed immunoelectron microscopy with multiple antibodies specific to each isozyme. Both PGHS-1 and -2 were found on the lumenal surfaces of the endoplasmic reticulum (ER) and nuclear envelope of human monocytes, murine NIH 3T3 cells, and human umbilical vein endothelial cells. Within the nuclear envelope, PGHS-1 and -2 were present on both the inner and outer nuclear membranes and in similar proportions. Western blotting data showed a similar distribution of PGHS-1 and -2 in subcellular fractions, and product analysis using isozyme-specific inhibitors suggested that both enzymes generate the same products in NIH 3T3 cells. Thus, we are unable to attribute the independent functioning of PGHS-1 and PGHS-2 to differences in their subcellular locations. Instead, the independent operation of these isozymes may be attributable to subtle kinetic differences (e.g. negative allosteric regulation of PGHS-1 at low concentrations of arachidonate (500-1000 nM)). A further conclusion of importance from a cell biological perspective is that membrane proteins such as PGHS-1 and -2, which are located on the lumenal surface of the ER, are able to diffuse freely among the ER and the inner and outer membranes of the nuclear envelope.     

Two-dimensional quantum-mechanical confinement of electrons in DH lasers by strong magnetic fields

Two-dimensional quantum-mechanical confinement of electrons in DH lasers is realized near room temperature by applying strong magnetic fields up to 32 T. In order to confirm the realization of two-dimensional quantum-mechanical confinement of electrons in such lasers, the spectral characteristics are measured. The observed shift of the lasing wavelength with magnetic fields is shown to correspond to the upward shift of the lowest Landau level with the increase of magnetic fields.     

Conditions for complete self-healing breakdown in glow discharge polymerized styrene films

Breakdown patterns of glow discharge polymerized styrene film sandwiched between the top and base electrodes and fabricated on a glass substrate have been observed with a microscope. The breakdown patterns can be classified into three types: a broad ring of partly vanishing top electrode metal occuring around the breakdown hole in the dielectric (type A); a large hole made through the three layers (one dielectric and two metal layers), the dielectric film and the top electrode being folded back together at the periphery of the hole and the base electrode being melted over the hole area (type B); successive breakdown around the periphery of previous breakdown spots (type P). These patterns are interpreted in terms of the action of an arc across an extremely short gap as well as joule heating. Type A is preferable for attaining complete self-healing and the conditions that most favour the occurrence of type A holes are (a) the application of a positive voltage to the top electrode and (b) the top electrode being thin compared with the base electrode.     

The use of intravenous immunoglobulin in Miller Fisher syndrome

We report a patient with Miller Fisher syndrome who was treated with an intravenous high-dose of immunoglobulin. This syndrome is considered to be a benign variety of acute inflammatory demyelinating polyneuropathy (Guillain-Barré syndrome). However, there have been several reports of the need for ventilatory support and a few cases have had a fatal outcome. We observed a case of progressive Miller Fisher syndrome in a 3-year-old boy. Following 2 episodes of apnea lasting about 50 s each, he was treated with intravenous immunoglobulin (400 mg/kg/day) for 5 consecutive days. His respiratory state, general muscle strength, truncal ataxia and emotional state improved remarkably after this therapy.     

Nodular glomerulosclerosis of unknown origin associated with the nephrotic syndrome

A 35-year-old male patient clinically characterized by massive proteinuria and hypertension without evidence of systemic diseases is reported. Histological investigation of renal biopsy specimens revealed extensive nodular formations in the mesangial areas in every glomerulus. Light-microscopic examination did not allow discrimination between the glomerular changes found in these specimens and the nodular glomerulosclerosis described in patients with diabetes mellitus. Electron-microscopic examination confirmed the presence of massive, nodular, mesangial expansions consisting of finely fibrillar substances without electron-dense deposits and circumferential mesangial interposition. Immunofluorescent examination showed deposition of IgG, C3, fibrinogen and kappa and lambda light chains in mesangial areas, peripheral capillary loops and a part of the nodules. Furthermore, collagen types IV, V, VI and laminin were detected in the nodules. Amyloid was not observed in these nodules. This diagnosis has not been made, and the mechanism of this nodular glomerulosclerosis remains unknown.     

A case of diabetic muscle infarction in Japan

Diabetic muscle infarction (DMI) is a rare complication of diabetes mellitus. We report the first recorded case in Japan. A 45-year-old Japanese woman presented with severe pain in the left antero-medial thigh. She had a 14-year history of Type 2 diabetes mellitus (DM). She had first noticed pain in her left thigh after a walk 2 weeks prior to presentation. The pain worsened progressively. She noticed a firm mass in her left thigh. T2-weighted magnetic resonance imaging (MRI) demonstrated a high-intensity signal in the muscle bulk of the anterior component of the left thigh. A needle biopsy of the mass showed necrosis. She was treated with bedrest and an antiplatelet agent. The mass disappeared 8 weeks after admission. DMI is a rare complication of poorly controlled diabetes mellitus. Twenty-seven cases with DMI have been reported in the English literature but we believe this is the first Japanese case with DMI.     

Three-dimensional spiral computed tomography angiography as an alternative imaging modality for a silent dissecting aortic aneurysm--a case report

The authors report a patient with silent dissecting aortic aneurysm in whom three-dimensional spiral computed tomography (CT) angiography (3D-CTA) provided important imaging data. Images obtained by 3D-CTA were compared with the results of both conventional angiography and CT. They conclude that 3D-CTA was a powerful diagnostic modality for this patient, in addition to conventional CT and angiography.     

Catalytic properties of compounds between the rare earths and copper oxide

The catalytic properties of the rare earth-copper double oxides (Ln₂CuO₄, Ln=La ～ Gd) are dependent on the kind of rare earth included and reveal drastic changes on going from Pr to Nd. The sequence of activity for Ln₂CuO₄ was $\text{Eu > Gd > Pr ? La > Sm}$.