The reactive site loop of the serpin SCCA1 is essential for cysteine proteinase inhibition

The high-molecular-weight serine proteinase inhibitors (serpins) are restricted, generally, to inhibiting proteinases of the serine mechanistic class. However, the viral serpin, cytokine response modifier A, and the human serpins, antichymotrypsin and squamous cell carcinoma antigen 1 (SCCA1), inhibit different members of the cysteine proteinase class. Although serpins employ a mobile reactive site loop (RSL) to bait and trap their target serine proteinases, the mechanism by which they inactivate cysteine proteinases is unknown. Our previous studies suggest that SCCA1 inhibits papain-like cysteine proteinases in a manner similar to that observed for serpin-serine proteinase interactions. However, we could not preclude the possibility of an inhibitory mechanism that did not require the serpin RSL. To test this possibility, we employed site-directed mutagenesis to alter the different residues within the RSL. Mutations to either the hinge or the variable region of the RSL abolished inhibitory activity. Moreover, RSL swaps between SCCA1 and the nearly identical serpin, SCCA2 (an inhibitor of chymotrypsin-like serine proteinases), reversed their target specificities. Thus, there were no unique motifs within the framework of SCCA1 that independently accounted for cysteine proteinase inhibitory activity. Collectively, these data suggested that the sequence and mobility of the RSL of SCCA1 are essential for cysteine proteinase inhibition and that serpins are likely to utilize a common RSL-dependent mechanism to inhibit both serine and cysteine proteinases.     

A case of retroperitoneal extramedullary plasmacytoma

Extramedullary plasmacytoma (EMP) is a very rare disease and mainly arises in the head and neck area. We herein reported a case of EMP arising in the retroperitoneal space. A 46-year-old man was referred to our outpatient clinic in November 1989 with the complaint of flank pain on the left side. Radiological examinations showed a tumor formation in the retroperitoneal space, which involved the left kidney, spleen and pancreas. Immunoelectrophoresis showed an elevation of serum IgG level and a spike of M-protein was detected in the serum protein electrophoresis. No bone lesions were detected, and bone marrow aspiration showed no abnormal cells. US-guided needle biopsy of the tumor led to the histological diagnosis as plasmacytoma of the IgG-kappa type. Following three cycles of preoperative chemotherapy (a THP-COP regimen), which resulted in a size reduction of the tumor by 40%, extensive resection of the tumor including extirpation of the left kidney, spleen, and tail of pancreas was performed. Because of tumor extension into the posterior wall of the stomach, however, the surgery resulted in incomplete resection. A total of 11 cycles of postoperative chemotherapy (THP-COP) was performed periodically for the residual tumor in the stomach. Rapid tumor spreading in addition to re-elevation of the serum IgG level, however, developed after the 11th postoperative chemotherapy, which extensively involved the stomach and intestines. The patient died of the disease 33 months after the initiation of treatment.     

Radiation hybrid mapping of the human MN/CA9 locus to chromosome band 9p12-p13

A previously healthy 12-year-old Japanese girl developed meningoencephalitis due to Cryptococcus neoformans. During the course of her illness she suffered persistent high fever, severe pancytopenia, hypercytokinemia and liver dysfunction. Laboratory findings, including results of a bone marrow examination, strongly indicated complication by haemophagocytic syndrome (HPS). The preceding cryptococcal infection was thought to be a cause of the HPS because no other viral or bacterial infection could be confirmed. The girl died of acute respiratory failure during the progressive course of HPS. This may be the first reported case of HPS due to cryptococcal infection in an otherwise healthy child.     

Development of a diode-pumped Kerr-lens mode-locked Cr:LiSAF laser

Kerr-lens mode-locked Cr:LiSrAlF/sub 6/ lasers are demonstrated with various prism pairs based on a recalculation of the condition for compensating the intracavity dispersion. The minimum pulse duration is 9.9 fs, which is the limit for ordinary nonchirped dielectric mirrors. To develop an efficient diode-pumped Kerr-lens mode-locked Cr:LiSAF laser, diode-pumping geometry is also discussed.     

A new twin-screw press design for oil extraction of dehulled sunflower seeds

Transport of material in a single-screw press depends mainly on friction between the material and the barrel’s inner surface and the screw surface during screw rotation. Thus, a solid core component, like seed hulls, is often necessary to produce the fraction. This sometimes causes excess frictional heat, large energy consumption and oil deterioration. Furthermore, if single-screw presses are not configured with breaker bars or other special equipment, they provide inadequate crushing and mixing. A twin-screw oil press can be expected to solve these problems because of the higher transportation force, similar to a gear pump, and better mixing and crushing at the twin-screw interface. A twin-screw press (screw diameter=136 mm, length/diameter=6.5, screw speed 15–100 rpm, feed rate=50–150 kg/h) was designed with partially intermeshing and counter-rotating screws and was tested on dehulled sunflower seed. The results were compared to a single-screw lab-scale press. Dehulled sun-flower seed (wt, 6.0%; oil, 58.6%) without pretreatments (crushing or cooking) gave 93.6% oil recovery with the twin-screw press, in contrast to 20% oil recovery with the single-screw press. The oil expressed with a twin-screw press had less foreign material than the oil from the single-screw press. Other properties of the oil were also good. Energy consumption of the twin-screw press was more efficient. All results suggested that oil production from dehulled sunflower seed with a twin-screw press is highly efficient.     

The interrelation between structure and mechanical properties of CNx (0 ≤ x ≤ 0.5) coatings obtained by graphite arc sputtering

Hardness, elastic modulus, internal stresses and friction coefficients were measured in CN_{0 ≤ x ≤ 0.5} coatings (1–3 μm). The dependence of these parameters on nitrogen concentration can be applied in the practical coatings. The structure investigations show that the domain amorphous matrix mixture consists of CN_{x ≤ 0.1} and CN_0.5. Such structure allows understanding the dependence of the CN_{0 ≤ x ≤ 0.5} coatings properties on nitrogen concentration. Through the structure, the coating properties of CN_{0 ≤ x ≤ 0.5}, depend on the nitrogen concentration.     

EFFECT OF DISTRIBUTOR ON BUBBLE SIZE AND BUBBLE RISE VELOCITY IN THE SLUGGING REGIME OF A SEMI-CYLINDRICAL GAS-SOLID FLUIDIZED BED†

A semi-cylindrical fluidized bed of 15 cm internal diameter, equipped with a transparent flat glass plate for the front wall, was employed to visually observe bubbles in the bubbling to slugging transition regime and in the slugging regime. Five kinds of perforated distributors were used to investigate the effect of distributor type on the bubble size and the bubble rise velocity. The average bubble size was not affected by distributor type in these flow regimes, and could be predicted by Darton et al's correlation (1974)of hole number 22. In other words, this comes from the inapplicability of the correlation to the slugging regime. The bubble rise velocity agreed well with Allahwala et al's correlation (1979) and was not affected by the type of distributor.