Contributions of interfacial residues of human Interleukin15 to the specificity and affinity for its private alpha-receptor

Human interleukin 15 (hIL15) is a soluble cytokine that plays a key role in the maintenance of long-lasting responses against pathogens and a valuable target for the treatment of autoimmune diseases. In this study, we sought to elucidate the thermodynamic basis of the recognition mechanism for its private alpha-receptor (hIL15Ralpha), considered the first step of the interleukin's activation pathway. Binding of wild-type hIL15 to its alpha-receptor is characterized by a very slow dissociation rate constant and driven by a favorable enthalpy change. We further studied the kinetic and energetic consequences of substituting residues of hIL15 located at the contact interface by means of the surface plasmon resonance technique. Replacement of negatively charged residues with Ala indicates that the energetics of interaction is primarily driven by electrostatic forces, manifested by a dramatic acceleration of the dissociation step and a reduction of favorable binding enthalpy. Our analyses also unveiled a novel and critical role for residue Tyr26 in the interaction, which facilitates desolvation of key charged residues during the assembly of the complex. These results were rationalized in terms of a previously reported structure of hIL15.hIL15alpha, demonstrating that the binding energetics is dominated by interactions occurring at three hot spots whose spatial locations coincide with a previously proposed structural division of the contact interface in three regions. Specifically, Region 1 is the main contributor to the binding energy of the complex by establishing very favorable electrostatic interactions with the receptor; Region 2 is also dominated by electrostatic forces, although of a lesser intensity; and Region 3 confers specificity to the association by means of high shape complementarity and by bringing additional stabilization energy to the complex. The biological impact of hIL15 mutations with the most effect on alpha-receptor binding was evaluated in a cell-based proliferation assay, validating the conclusions of our thermodynamic analyses and highlighting the functional importance of molecular contacts that promote prolonged binding of the interleukin to the alpha-receptor. In closing, the thermodynamics and physicochemical nature of the interactions observed in IL15h.IL15Ralpha complex, together with interactions in Region 3 of the interleukin, poses a stark contrast with the structurally related and sometimes functionally redundant interleukin 2.

Emission of terahertz radiation from dual grating gate plasmon-resonant emitters fabricated with InGaP/InGaAs/GaAs material systems

This paper reviews recent advances in our original 2D-plasmon-resonant terahertz emitters. The structure is based on a high-electron-mobility transistor and featured with doubly interdigitated grating gates. The dual grating gates can alternately modulate the 2D electron densities to periodically distribute the plasmonic cavities along the channel, acting as an antenna. The device can emit broadband terahertz radiation even at room temperature from self-oscillating 2D plasmons under the DC-biased conditions. When the device is subjected to laser illumination, photo-generated carriers stimulate the plasma oscillation, resulting in enhancement of the emission. The first sample was fabricated with standard GaAs-based heterostructure material systems, achieving room temperature terahertz emission. The second sample was fabricated in a double-decked HEMT structure in which the grating gate metal layer was replaced with the semiconducting upper-deck 2D electron layer, resulting in enhancement of emission by one order of magnitude.

A possible role of autogenous IFN-beta for cytokine productions in human fibroblasts

It has been already known that human diploid fibroblasts are able to produce not only high levels of IFN-beta but also various kinds of cytokines by poly rI: poly rC, and some inflammatory cytokines are induced by IFN-beta gene activation. We also obtained similar results. However, in our system, cytokine productions were extremely enhanced by treating the cells with a low dose of type 1 IFN and the priming effects on cytokine productions were blocked by cycloheximide similar to those on IFN-beta productions. Most of cytokines were produced later than IFN-beta and synthesis patterns of their mRNA showed the same phenomena. We made clear that cytokine productions by poly rI: poly rC are mediated by secreted IFN-beta at a protein level using a monoclonal antibody against human IFN-beta. Further, it was shown that intra-cellular IFN-beta which is not secreted might also participate in cytokine productions. Meanwhile, IL-1beta induced various kinds of cytokines in human fibroblasts and production time courses of these cytokines were similar to those of poly rI: poly rC induced cytokines. Although secreted IFN-beta was not detected in IL-1beta stimulated culture, expression of IFN-beta mRNA was augmented. These results showed that priming effects of type 1 IFN on cytokine productions by poly rI: poly rC might not be the direct action, but successive IFN-beta production might be essential in the production processes of other cytokines. Further, it was suggested that inducible IFN-beta might also take part in IL-1beta-induced cytokine productions.

A nursing tool validated as an effective measure over MMSE and FAB in dementia

AIM

To evaluate the clinical use of the Abilities Assessment Instrument (AAI) when used together with Mini Mental State Examination (MMSE) and Frontal Assessment Battery (FAB), thus examining the concurrent validity of the instrument. Also, to evaluate the effect of a learning program administered for elders with dementia.

METHODS

Fourteen older people, who were afflicted with Alzheimer's disease or related dementias, were invited into a learning program. Measures were taken at baseline, at 3 months and 6 months to see the effects of the program. Instruments used in the study were the AAI, the MMSE and the FAB.

FINDINGS

There were statistically significant differences measured by the Japanese version of the AAI in the subjects' abilities to perform the learning tasks between 3 and 6 months after intervention. No statistical significant differences were noted at any points in time measured by the MMSE or the FAB.

CONCLUSION

The translated AAI promises to be a valid instrument for nurses' use in their day-to-day assessment of Japanese elders. The AAI appears also to be useful in learning programs with this population, and may have value as a screening tool.

Movement of viruses between biomes

Viruses are abundant in all known ecosystems. In the present study, we tested the possibility that viruses from one biome can successfully propagate in another. Viral concentrates were prepared from different near-shore marine sites, lake water, marine sediments, and soil. The concentrates were added to microcosms containing dissolved organic matter as a food source (after filtration to allow 100-kDa particles to pass through) and a 3% (vol/vol) microbial inoculum from a marine water sample (after filtration through a 0.45-microm-pore-size filter). Virus-like particle abundances were then monitored using direct counting. Viral populations from lake water, marine sediments, and soil were able to replicate when they were incubated with the marine microbes, showing that viruses can move between different ecosystems and propagate. These results imply that viruses can laterally transfer DNA between microbes in different biomes.

Identification of interleukin-8 converting enzyme as cathepsin L

IL-8 is produced by various cells, and the NH(2)-terminal amino acid sequence of IL-8 displays heterogeneity among cell types. The mature form of IL-8 has 72 amino acids (72IL-8), while a precursor form (77IL-8) of IL-8 has five additional amino acids to the 72IL-8 NH(2)-terminal. However, it has been unclear how IL-8 is processed to yield the mature form. In this study, converting enzyme was purified as a single 31-kDa band on silver-stained polyacrylamide gel from 160 l of cultured fibroblast supernatant by sequential chromatography. NH(2)-terminal amino acid sequence analysis revealed a sequence, EAPRSVDWRE, which was identified as a partial sequence of cathepsin L. Polyclonal antibodies raised against cathepsin L recognized the purified converting enzyme on Western blot. Moreover, human hepatic cathepsin L cleaved 77IL-8 between Arg(5) and Ser(6), which is the same cleavage site as the putative converting enzyme, resulting in 72IL-8 formation. These data indicate that the converting enzyme of the partially purified fraction of the human fibroblast culture supernatant was cathepsin L. Furthermore, 72IL-8 was sevenfold more potent than 77IL-8 in a neutrophil chemotaxis assay. These results show that cathepsin L is secreted from human fibroblasts in response to external stimuli and plays an important role in IL-8 processing in inflammatory sites.

New functions of lactoferrin and beta-casein in mammalian milk as cysteine protease inhibitors

We found new inhibitory function of lactoferrin and beta-casein in milk against cysteine proteases using reverse zymography. The inhibition of cathepsin L by lactoferrin was strongest and the inhibition kinetics were of a non-competitive type. Heat denatured lactoferrin lost the inhibitory activity completely, therefore the tertiary structure is essential to show the inhibition. Native lactoferrin was not degraded by papain during the assay condition. The intramolecular peptide, Y(679)-K(695), of lactoferrin is an active domain and the synthesized peptide inhibited cysteine proteases. The Y(679)-K(695) peptide showed 90% homology with the sequences of a common active site of cystatin family. beta-Casein and the active domain, synthesized L(133)-Q(151), peptide inhibited cysteine proteases. Lactoferrin and beta-casein in milk might play a role in antiseptic and antiinfectious functions due to cysteine protease inhibition of bacteria and viruses.

Possible identity of IL-8 converting enzyme in human fibroblasts as a cysteine protease

A converting activity was characterized in human diploid fibroblasts, which secrete 72IL-8 and 77IL-8 in treatment with IFN-beta and poly I: poly C. 77IL-8 was significantly converted to 72IL-8 by a partially purified fraction of the culture supernatant of human diploid fibroblasts. The converting activity, which was temperature-dependent and optimal at pH 6, was completely inhibited by cysteine protease inhibitors, antipain dihydrochloride and E-64, but not by other types of protease inhibitors. These data clearly show that human diploid fibroblasts are capable of processing IL-8 to produce a mature IL-8 and that the putative converting enzyme appears to be a cysteine protease.

[Three-channeled aortic dissection: selection of surgery based on the images]

Three patients with 3-channeled dissection were operated upon. Images of the dissection were enlargement of the false lumens, compression of the true lumen by enlarged false lumens and visceral arteries of false lumen origin. These prevent the use of cardiopulmonary bypass (CPB) and cause malperfusion of the viscera. Three-channeled dissecion is easy to rupture for its peculiar anatomy and total repair of the thoraco-abdominal aorta is mandatory. Fenestration brings functional recovery of malperfused viscera and enables the patients to be placed on CPB for total repair. Two patients underwent infrarenal and descending aorta fenestration followed by the total repair of thoraco-abdominal aorta successfully. A third patient has been placed on the strict CT follow-up following the infrarenal fenestration.

[Double chambered right ventricle in a 62-year-old female: a surgical case report]

A 62-year-old female was admitted with a chief complaint of transient syncope on exertion. Angiography in right ventricle revealed a defect caused by an anomalous muscle bundle and a pressure gradient of 151 mmHg was observed between the two chambers by cardiac catheterization. Resection of the anomalouse muscle bundle was undertaken using a lower median sternotomy starting at the 2nd intercostal space level and through the outflow tract right ventriculotomy. Patch plasty was also undertaken in the outflow tract. Post-operative course was uneventful and pressure gradient had disappeared at the post-operative catheterization. A rare case of DCRV in a 62-year-old patient with a pressure gradient of 151 mmHg in the right ventricle was reported.

Chromatin structure of the rat somatotropin gene locus and physical linkage of the rat somatotropin gene and skeletal-muscle sodium-channel gene

Cosmid clones from -32 kb to +74 kb region of the rat somatotropin gene locus were isolated for examination of the chromatin structure in the region from -39 kb to +47 kb by DNase I-sensitivity analysis using rat pituitary-derived GC (somatotropin+, prolactin-), and 235 (somatotropin-, prolactin+) cells, and liver-derived BRL (somatotropin-, prolactin-) cells. DNase I-hypersensitive sites (DHS) specific for somatotropin-producing cells were previously shown to be located exclusively in the -2 kb to +9 kb region [Aizawa, A., Yoneyama, T., Kazahari, K. & Ono, M. (1995) Nucleic Acids Res. 23, 2236-2244]. No other DHS having this specificity was found in the region examined in this study. Except for these and two other DHS located in a cluster in this region, no DHS could be found from -23 kb to +22 kb. DHS having no or less cell-type specificity were scattered about in the -39 kb to -23 kb and +22 kb to +47 kb regions. The polyadenylation site of the human skeletal-muscle Na-channel alpha-subunit gene has been shown present 22 kb upstream from the somatotropin gene [Bennani-Baiti, I. M., Jones, B. K., Liebhaber, S. A. & Cooke, N. E. (1995) Genomics 29, 647-652]. Polyadenylation site of the rat skeletal-muscle Na-channel gene was shown in this study to be at -15.7 kb. The skeletal-muscle Na-channel gene was specifically expressed in skeletal-muscle cells but not in somatotropin-producing cells, and thus the boundary region that ensures the cell-type-specific expression of each gene would appear to be situated between two genes. The region prerequisite for cell-type-specific expression of the rat somatotropin gene was estimated based on the present findings.

[Mitral obstruction due to infective endocarditis: a case report]

Acute valvular obstruction caused by vegetation is a rare complication infective endocarditis. To our knowledge, only 9 cases and an autopsy case by Roberts have been reported since 1967. A 46-year-old man admitted with a chief complaint of pyrexia for 2 months duration. Within 24 hours of admission, the patient noticed of increased shortness of breath. Physical examination and the chest X-ray confirmed the pulmonary edema. An echocardiogram revealed a huge echogenic mass that was adherent to the mitral leaflet and obstructed the orifice completely. Soon after the patient fell into cardiogenic shock, an emergency mitral valve replacement was undertaken. At operation, multiple verrucae arising from the entire mitral leaflet was seen to occlude the orifice. The vegetation was excised and replaced with a # 25 Omnicarbon prosthesis. Postoperatively, the patient developed multiple organ failure caused by cardiogenic and septic shock which responded well to intensive medical treatment consisting of hemodialysis and continuous arteriovenous hemofiltration. Angiographically, a mycotic aneurysm in the left radial artery was found on the 18th postoperative day. After extirpation of the infective focuses, the postoperative course had stabilized. Mitral obstruction due to infective endocarditis is a fatal disease. Prompt diagnosis with echocardiogram and an emergency surgery should be undertaken to save the patient.

[A case of traumatic aneurysm of the thoracic aorta with severe chronic compression of the trachea]

A case of successfully treated traumatic aneurysm of the thoracic aorta with severe major air way compression was reported. A 38-year-old man, who had a history of blunt chest trauma in a traffic accident twenty years ago, complained of asthma-like coughing chest CT scan and angiogram showed a saccular aneurysm of desending aorta compressing the isthmus of the trachea and the esophagus severely. Resection of the aneurysm and prosthetic graft replacement was undertaken successfully with the aid of F-F bypass. The trachea and the esophagus were well decompressed and the patient recovered well with no complaints.

[Sex determination with a discriminant function analysis of deciduous teeth size in plaster models]

Plaster models of the teeth of 3-year-old Japanese children (96 males, 98 females) were used to record the crown length, crown width and crown thickness of 5 maxillary and 5 mandibular deciduous teeth (30 measurement values). These measurements were used to devise a number of sex determination formulae. A sex-determination formula using all 30 values was calculated. Furthermore, a number of practical formulae were derived from only the crown width and crown thickness values because the deciduous teeth wear in 4 years and older children rapidly progress, making the crown length measurement unreliable. These formulae were calculated for the maxillary teeth alone and mandibular teeth alone. The formulae based on only the crown width or thickness were also calculated for both maxillary and the mandibular teeth. A step-wise discriminant analysis was then used to ascertain the most reliable measurements and a practical formula subsequently devised. The results obtained were as follows: 1. The mean value for each measurement was greater in males than in females. 2. Significant differences in the values recorded were seen in 28 out of the 30 measurements taken. The measurement items not exhibiting these significant differences were the crown width of the maxillary lateral incisor and the crown thickness of the mandibular second molar. 3. The accuracy rates for the sex-determination analysis and the step-wise sex determination analysis calculated using all 30 values were 78.6% and 75.7%, respectively. 4. The accuracy ranges for the modified sex-determination formulae and the associated step-wise sex determination analyses were 70.6-78.4% and 67.0-76.8%, respectively.

Production of multiple growth factors by a newly established human thyroid carcinoma cell line

A multiple growth factor‐producing tumor cell line (NIM‐1) was newly established from a patient with thyroid cancer and remarkable neutrophilia. NIM‐1 cells also caused severe neutrophilia in nude mice bearing tumors. NIM‐1‐conditioned medium (NIM‐1CM) contained activities that supported not only granulocyte, macrophage and eosinophil colony formation of human bone marrow cells but also the growth of colony‐stimulating factor (CSF)‐dependent cell lines, NFS60‐KX and TF‐1. Northern blot hybridization analysis revealed the constitutive expression of granulocyte‐CSF (G‐CSF), granulocyte/macrophage‐CSF (GM‐CSF) and interleukin(IL)‐6 mRNAs in NIM‐1 cells. Enzyme‐linked immunosorbent assays (ELISA) using NIM‐1CM also confirmed the production of IL‐la and a small amount of IL‐1β besides G‐CSF, GM‐CSF and IL‐6 in NIM‐1 cells. In addition, unexpected production of IL‐11 in NIM‐1 cells was detected by northern blot hybridization analysis and by bioassay using an IL‐11‐dependent cell line. Therefore, NIM‐1 cell line is shown to produce multiple cytokines including potentially megakaryopoietic growth factors such as GM‐CSF, IL‐6 and IL‐11.

[Pulmonary thromboembolectomy of subacute massive pulmonary thromboembolism in a patient with familial antithrombin III deficiency]

Reported is a case of successful pulmonary thromboembolectomy and inferior caval vein interruption in a patient with subacute massive pulmonary thromboembolism (PTE). He had been complicated by the right atrial and deep vein thrombosis due to type I familial antithrombin III (ATIII) deficiency. Pulmonary embolectomy and caval interruption was performed 20 days after the initial attack and followed by anti-coagulation therapy. Thrombi weighed 50 gm were removed mainly from the left pulmonary artery. The right atrial thrombus which had got smaller by the preoperative fibrinolytic therapy could not be found with right atriotomy. Respiratory function at rest and slightly elevated pulmonary arterial pressure was normalized post-operatively. Although the PTE in this patient was considered to be subacute by the histological findings of the fibrin thrombus removed, tapering of pulmonary arteries in PAG and obstructive intimal hypertrophy of the small vessels in the lungs suggests the chronic nature of the PTE (post-thrombotic obstruction of pulmonary arteries) caused by the hyper-coagulable state. In patients with familial ATIII deficiency, 50% of normal ATIII activity can be expected because they are heterozygotes, so the cardio-pulmonary bypass should be run with special caution to the heparin dosage. Caval vein interruption and warfarin therapy are recommended for prophylaxis of recurrent PTE.

[Reconstruction of radicular arteries in the total replacement of thoracoabdominal aorta]

A technique of reconstructing low intercostal, high lumbar arteries and Adamkiewicz artery is described to prevent paraplegia following operations on the thoracoabdominal aorta. A graft with a side branch is anastomosed proximally and a side branch to the distal thoracic aorta after reinforcement of the stumps under the partial bypass. Applying a clamp on the main graft, flow through the side branch and true lumen of the aneurysm is reestablished and bypass is terminated. The main graft, extended with a Y-graft, is anastomosed to common iliac arteries after proximal suture-ligation to perfuse the lower extremities. Splanchnic arteries are reconstructed according to DeBakey's technique which is followed by trimming of the thoracoabdominal aorta incising longitudinally with a clamp applied on the 1st side branch. Edges of the trimmed aneurysm are sutured to the slit of the graft from the right common iliac artery reconstructing intercostal, lumbar arteries and Adamkiewicz artery from the level of L2 upwards to T4 or more. As a final step, the graft is sutured to the 1st side branch allowing perfusion distally to the right lower extremity and the main graft to the splanchnic arteries and left lower extremity after division of a Y-graft right branch. The technique minimizes ischemic time for reconstruction of the aortic branches and enables complete reconstruction of the radicular arteries.

Effect of glucocorticoid hormones on the growth of human fibroblast cells and interferon production

Human diploid fibroblasts could be passaged serially on microcarriers and used as an efficient system for the bulk production of human interferon-beta (IFN-beta), provided that appropriate amounts of glucocorticoid hormones were added to the fetal bovine serum used in the medium; alternatively, precolostrum newborn calf serum, which has a relatively high content of hydrocortisone, could be used.

Structural characterization of recombinant human interferon-gammas derived from two different mammalian cells

Recombinant human interferon-gammas (rHuIFN-gamma s) were obtained from two different mammalian cells (mouse C127 cells and Chinese hamster ovary, CHO, cells) cultured in a microcarrier culture system. Both rHuIFN-gamma s were purified using sequential chromatographies for their comparison of structural properties. The peptide maps of HuIFN-gamma s digested with V8 protease and Western blot analysis demonstrated that C127 cells yielded mainly about 25kDa component and CHO cells produced about 25kDa and about 20kDa components. By the identification of glycosylated peptides, it was suggested that 20kDa and 25kDa components are glycosylated at one and at two sites, respectively. C-terminal amino acid sequence analysis indicated that both rHuIFN-gamma s consisted of at least six different species lacking 2 to 16 amino acid residues from C-terminus, so that C-termini of both rHuIFN-gamma s were slightly different from each other. Amino acid sequence and composition analyses of N-terminal peptides demonstrated that N-termini of both rHuIFN-gamma s were blocked and were supposed to be identical with that of natural HuIFN-gamma. These results suggested that different molecular heterogeneities of rHuIFN-gamma s resulted from the difference of post-translational modifications of host cells.

Constitutive long-term production and characterization of recombinant human interferon-gammas from two different mammalian cells

Two expression plasmids (pSVIFN gamma/BPV97 and pSVIFN gamma/AdDHFR) for constitutive production of human interferon-gamma (HuIFN-gamma) were constructed and introduced into the two different mammalian cell lines, mouse C127 cells and Chinese hamster ovary (CHO) cells. Genetically engineered C127 and CHO cells grew on microcarriers having high productivity of HuIFN-gammas for at least six months. Isoelectric focusing patterns and molecular weight analyses suggest that C127- and CHO-HuIFN-gammas are glycoproteins and that both HuIFN-gammas have different molecular structures. The development of a microcarrier culture system for genetically engineered mammalian cells has enabled us to prepare glycosylated HuIFN-gammas on a large scale.

Effect of glucocorticoid hormones on growth of human fibroblast cells and interferon production in a microcarrier culture system

Glucocorticoid hormones promoted the growth of fibroblast cells derived from human neonatal foreskins and prolonged their life span in a microcarrier culture system that used Eagle's minimum essential medium (MEM) supplemented with fetal calf serum (FCS). But, these hormones suppressed cell growth in conventional monolayer cultures. Precolostrum newborn calf serum (PNCS) was the only species that supported the serial propagation of fibroblast cells on microcarriers, possibly because of its high content of hydrocortisone (HC). Fibroblast cells grown on microcarriers in the presence of glucocorticoid hormones maintained their ability to produce interferon (IFN)-beta in a superinduction method with poly I: poly C and antimetabolites. These cells had more than 93% diploidy and no chromosomal aberration or translocation. Use of PNCS for the cultivation of human fibroblast cells has high potential for providing a microcarrier culture system for the mass production of human IFN-beta.

Carcinoma in heterotopic gastric pancreas

A case of a 55-year-old Japanese female who died of adenocarcinoma originating from heterotopic gastric pancreas is presented. The autopsy revealed, extensive metastases of bones. Though careful examination was done, other primary focus except that of the stomach could not be detected. In review of literatures, 11 malignant tumors originating from heterotopic gastric pancreas could be found including our case.