[Surgical repair for ischemic mitral regurgitation: a method of mitral valve plasty with evaluation of morphological changes of mitral valve]

We evaluated a method of mitral valve plasty (MVP) for ischemic mitral regurgitation (IMR) by examining the morphological changes of the mitral valve. From November 1992 to May 1998, 8 patients (M : F = 4/4, age 44-79 years, mean age 65.1 years) with IMR underwent surgical repair. Preoperative mitral regurgitation (MR) was grade III of Sellers classification in 7 patients and grade IV in 1 patient. The cause of MR was mitral valve annular dilatation in 4 patients, mitral valve prolapse due to papillary muscle elongation in 2 patients, and partial papillary muscle rupture (PMR) in 2 patients. Cardiac surgery consisted of CABG + MVP in 7 patients and MVP in 1 patient. Mitral valve repair was separated into three types. Repair for annular dilatation consisted of commissuroplasty in 3 patients (2 patients Kay method, 1 patient Reed method) and ring annuloplasty using a Carpentier-Edwards ring (C-E ring) in 1 patient. Repair for papillary muscle elongation consisted of papillary muscle shortening and ring annuloplasty using a C-E ring. Repair for partial PMR consisted of papillary muscle implantation and ring annuloplasty for anterior leaflet prolapse in 1 patient, and quadrangular resection, posterior leaflet plasty (McGoon method) and ring annuloplasty in 1 patient. There was no hospital death. Postoperative outcome was 6 patients with no MR and 2 patients with grade II MR, but they were well-controlled with medication. Based on the morphological changes of the mitral valve, it is considered that MVP for IMR is an effective and recommended procedure.

Lambert-Eaton myasthenic syndrome associated with idiopathic thrombocytopenic purpura and diffuse panbronchiolitis: long-term remission after a course of intravenous immunoglobulin combined with low-dose prednisolone

We report a case of Lambert-Eaton myasthenic syndrome (LEMS) associated with idiopathic thrombocytopenic purpura (ITP) and diffuse panbronchiolitis (DPB). An extensive search for malignancy yielded negative results. Interestingly, ITP and DPB developed simultaneously when the patient suffered from myasthenic symptoms. This is the first report in the Japanese or English literature of an association of LEMS, ITP, and DPB. The use of cholinesterase blocker alone did not improve the myasthenic symptoms, and the symptoms and signs relapsed with the tapering of prednisolone (PSL) dosage. However, after administration of immunoglobulin (IVIG) (0.4 g/kg/day x 5 days), low-dose PSL (20 mg/day) alleviated the LEMS and ITP, and the diseases have remained in remission for 8 months without additional IVIG. We suspect that there is a synergistic relationship between IVIG and PSL.

Blood flow of the gluteus medius muscle. An animal study

We investigated the effects of subperiosteal dissection on blood flow in the gluteal medius muscle in adult rabbits using the hydrogen washout technique. After the control blood-flow rate was determined, 8 rabbits were separated into 2 groups according to the direction of the dissection. The gluteal medius muscle was dissected from the iliac crest in the proximal-distal direction in 10 hips. In another 6 hips, the greater trochanter was osteomised and the gluteus medius muscle was dissected from the ilium in the distal-proximal direction. Dissection of the middle third of the gluteus medius muscle caused the most significant reduction in blood flow, more than 50% in both groups. This result indicates that minimising damage to the mid-portion of the gluteus medius muscle is important for reducing the incidence of post-operative complications.

Shape and energetics of a cavity in c-Myb probed by natural and non-natural amino acid mutations

The shape and the energetics of a functional cavity in the R2 subdomain (90-141) of the c-Myb DNA-binding domain were investigated by spectroscopy and thermodynamic analysis. We focused on the valine 103 residue located in front of the cavity. Nine mutants, in which valine 103 was substituted with alanine, 2-aminobutyric acid, norvaline, norleucine, leucine, isoleucine, allo -isoleucine, cyclohexylglycine, and cyclohexylalanine, were chemically synthesized and analyzed. These mutants provided a wide distribution of sizes which ranged from forming additional cavity space to filling and overflowing the cavity space. Temperature-scanning circular dichroism measurements and differential scanning calorimetry revealed a linear relationship between the van't Hoff enthalpy and the thermal transition temperature for the cavity-filling mutations. On the other hand, the mutants with side-chains larger than the side-chain of leucine resulted in a relatively low transition enthalpy and temperature, most likely due to the exposure of the side-chain to solvent and the increase in the entropy of the folded states. Branching at the beta-carbon atom reduced the unfolding free energy due to the steric constraint in the cavity. In particular, the mutational elongation of the side-chain from beta-carbon to the trans -to-CO direction proved to be more hindered than that from beta-carbon to the trans -to-NH. The unfolding free energy versus side-chain volume formed a bell-shaped plot with a maximum free energy for the leucine mutant. The difference in the transition free energy for cavity-filling mutants with beta-unbranched side-chains were two to four times larger than the difference in the transfer energy from organic solvent to water. Therefore, the increase in unfolding free energy would most likely be attributed to van der Waals interactions in the cavity wall, which would be a origin of stabilization by the sliding of tryptophan 95 into the cavity upon DNA binding.

Intramuscular spindle cell hemangioendothelioma

Spindle cell hemangioendothelioma occurring in skeletal muscle is extremely rare. No reported studies have performed an imaging evaluation of intramuscular spindle cell hemangioendothelioma. We report on such a tumor arising in an unusual site, the right extensor digiti minimi, in a 46-year-old woman. An en bloc resection was performed and the patient has been disease free for 8 years. Radiologic imaging in the present case showed similar findings to those described in intramuscular hemangioma.

Transtrochanteric curved varus femoral osteotomy for spondyloepiphyseal dysplasia tarda. A case report

A female with spondyloepiphyseal dysplasia (SED) tarda suffered bilateral hip pain since about the age of ten. Her radiographs revealed subluxation and irregularity of the hip joints with acetabular dysplasia. Transtrochanteric varus osteotomy was performed on her left femur at 13 years of age and on her right femur at 14 years of age. The congruities of both hips improved after surgery. At follow-up, she had no pain in either hip even after walking for an extended period. Improved activity in daily life was noted.

Roles of asp126 and asp156 in the enzyme function of sphingomyelinase from Bacillus cereus

To elucidate the roles of conserved Asp residues of Bacillus cereus sphingomyelinase (SMase) in the kinetic and binding properties of the enzyme toward various substrates and Mg2+, the kinetic data on mutant SMases (D126G and D156G) were compared with those of wild type (WT) enzyme. The stereoselectivity of the enzyme in the hydrolysis of monodispersed short-chain sphingomyelin (SM) analogs and the binding of Mg2+ to the enzyme were not affected by the replacement of Asp126 or Asp156. The pH-dependence curves of kinetic parameters (1/Km and kcat) for D156G-catalyzed hydrolysis of micellar SM mixed with Triton X-100 (1:10) and of micellar 2-hexadecanoylamino-4-nitrophenylphosphocholine (HNP) were similar in shape to those for WT enzyme-catalyzed hydrolysis. On the other hand, the curves for D126G lacked the transition observed for D156G and WT enzymes. Comparison of the values and the shape of pH-dependence curves of kinetic parameters indicated that Asp126 of WT SMase enhances the enzyme's catalytic activity toward both substrates and its binding of HNP but not SM. The deprotonation of Asp126 enhances the substrate binding and slightly suppresses the catalytic activity toward both substrates. Asp156 of WT SMase acts to decrease the binding of both substrates and the catalytic activity to HNP but not SM. From the present study and the predicted three-dimensional structure of B. cereus SMase, Asp126 was thought to be located close to the active site, and its ionization was shown to affect the catalytic activity and substrate binding.

Crystallization and preliminary X-ray analysis of wild-type and V103L mutant Myb R2 DNA-binding domain

The R2 subdomain of the mouse c-Myb DNA-binding domain and its V103L mutant have been crystallized by the vapour-diffusion method using highly concentrated sodium citrate at pH 6.8 as a precipitant. Using ammonium sulfate as precipitant in MES buffer only produced crystals for the mutant R2. All crystals are isomorphous and belong to space group P212121. The unit-cell dimensions for wild-type R2 crystals grown from sodium citrate precipitant are a = 28.83, b = 40.18, c = 49.23 A. Crystals contain one R2 molecule per asymmetric unit. They are stable during 3 d exposure to X-rays and diffract to 1.37-1.45 A resolution.

[A case of spinal myoclonus associated with epidural block for lumbago]

We herein report a case of spinal myoclonus following the administration of epidural anesthesia. A 25-year-old woman underwent lumbar epidural anesthesia because of lumbago and cramps in her left lower limb. She immediately felt a lancinating pain in her left limb during anesthesia at the level of L 4/5 and soon developed myoclonus in her left thigh. The neurological examination revealed rhythmic myoclonus in the left quadriceps and adductor thigh muscles. The myoclonus disappeared after performing a blockade of the left L 4 spinal root by using 1.5 ml of 1% lidocaine. An injury to the left L 4 nerve root during the epidural anesthesia possibly caused an abnormal transmission of the impulses or ectopic hyperexcitability in the nerve root, which might lead to the disturbance of the spinal inhibitory interneurons and hyperexcitability of the anterior horn cells causing myoclonus. Since she did not demonstrate any muscular weakness, nor sensory loss during the lidocaine block, the 1% lidocaine appeared to block the sympathetic nerves or to suppress the ectopic hyperexcitability. The sympathetic nerves may be involved in the development of her spinal myoclonus.

Aeromonas sobria infection with severe soft tissue damage and segmental necrotizing gastroenteritis in a patient with alcoholic liver cirrhosis

A 49-year-old man, who had a 3-year history of liver dysfunction but had not been treated, was admitted to the hospital with a sudden onset of fever and generalized muscle pain. He subsequently developed generalized purpura with scattered hemorrhagic bullae of the skin and massive bloody stools. Aeromonas sobria was proven by culture of both blood and bullous fluid. In spite of the extensive treatment with antibiotics and other medications in the intensive care unit (ICU), the patient went into septic shock and died 2 days after admission. Pathological examination on autopsy revealed segmental necrotizing gastroenteritis with bacterial colonies and alcoholic liver cirrhosis, in addition to extensive severe soft tissue damage involving cellulitis and rhabdomyolysis and epidermolysis. Although the prognosis for Vibrio vulnificus infection with severe soft tissue damage in patients with liver cirrhosis, malignancy, diabetes mellitus or other pre-existing diseases is poor, the unfavorable progression of Aeromonas species, especially A. sobria infection is rare. This is thought to be the first report of an autopsied case.

Successful treatment of adolescent pemphigus vulgaris by immunoadsorption method

A 15-year-old girl with pemphigus vulgaris did not respond to oral administration of prednisolone at 45 mg/day. The skin and oral mucous membrane lesions recurred after effective treatments with methylprednisolone pulse therapy and combination therapy with prednisolone and cyclosporine. The finally successful treatment involved eleven cycles of immunoadsorption using a tryptophan column and administration of a moderate dose of prednisolone. Serum gamma-globulin level and anti-intercellular antibody titer decreased from 1.08 g/dl to 0.5 g/dl and 1:320 to 1:20, respectively. She has been well controlled with 21.5 mg/day prednisolone for 8 months after the final adsorption. Considering the physical, mental and social situation of adolescent student patients, immunoadsorption is a highly preferable choice among a variety of treatment modalities for pemphigus vulgaris because it makes the term of hospitalization shorter and avoids undesirable side effects from initial high dose corticosteroids.

[Prandial hypoxia in progressive muscular dystrophy]

Progressive muscular dystrophy patients often show progressive body weight loss in early adolescence. This severe body weight loss frequently causes superior mesenteric artery syndrome which may result in a fatal outcome. We performed prandial pulse oximetry and found 12 out of 35 Duchenne muscular dystrophy patients, 1 out of 2 Becker muscular dystrophy patients and 1 out of 3 Limb-Girdle muscular dystrophy patients showed prandial hypoxia with tachycardia. The patients became tired and eating habits were easily interrupted resulting in progressive body weight loss. Nasal administration of 0.2L/min oxygen to 2 Duchenne muscular dystrophy patients, and nasal intermittent positive pressure ventilation to 2 Duchenne muscular dystrophy patients, 1 Becker muscular dystrophy patient and 1 Limb-Girdle muscular dystrophy patient for 15-30 minutes before eating improved the prandial hypoxia and halted the progression of body weight loss. This prandial hypoxia is one of the earliest signs of respiratory failure in progressive muscular dystrophy.

Intraoperative limb length measurement in total hip arthroplasty

In order to evaluate the efficacy of intraoperative measurement of limb length inequality (LLI), we performed a prospective study on 64 patients who underwent unilateral total hip arthroplasty. The patients were divided into 2 groups. In Group I, the LLI was evaluated by the Shuck test, and in Group II by intraoperative measurement using a Steinman pin and an adjustable caliper. Preoperative LLIs assessed on radiographs averaged 1.18 cm in Group I and 0.37 cm in Group II.

Constructing a local district telepathology network in Japan. Diagnosis of intraoperative frozen sections via telepathology over an integrated service digital network and the National Television Standard Committee System

OBJECTIVE

To construct a local telepathology network between the Department of Pathology, Tohoku University Hospital, and Koritu Kesennuma Hospital, about 150 km away.

STUDY DESIGN

Tohoku University Hospital is connected with Koritu Kesennuma Hospital by an integrated service digital network for telepathology using the National Television Standard Committee system. The cases submitted for telepathology were limited to those in which a rapid intraoperative diagnosis was made on frozen sections.

RESULTS

At this writing, more than 200 cases were diagnosed during a period of 2.5 years. The cases submitted increased with time, amounting to 150 in 1996. In some cases the use of telepathology proved to be fairly advantageous. For example, in one case a radical operation was avoided because of a diagnosis on intraoperative frozen sections.

DISCUSSION

There are problems to be solved before telepathology becomes available for practical use: (1) misdiagnosis due to poor quality of instruments, including the transmission cable and pictures; (2) cost-benefit ratio, (3) protection of patients' privacy, and (4) overwork for pathologists. The Japanese government will officially accept telepathology as a means of medical examination in the future. Despite some problems left, telepathology is a promising technology.

Oral administration of leflunomide (HWA486) results in prominent suppression of immunoglobulin E formation in a rat type 1 allergy model

Leflunomide, a drug being developed for use in the treatment of rheumatoid arthritis, was evaluated in an ovalbumin (OVA)-induced rat type 1 allergy model. In a dose of 1 mg/kg/day, it strongly suppressed the formation of OVA-specific IgE, thus preventing the elevation of the plasma histamine level and induction of anaphylactic shock observed after i.v. challenge with OVA. Studies on leflunomide's effects on the secondary antibody response showed that administration during the primary immune response remarkably diminished the secondary antibody responses, except IgM, even without further drug administration. Furthermore, when administered during the secondary response after rechallenge, both the total IgE and OVA-specific IgE serum levels declined rapidly to nearly baseline levels. Although OVA-specific IgG1, IgG2a, and IgM did not decrease from their primary response levels, these classes' secondary responses were strongly suppressed. In an in vitro study, the proliferation and antibody production of OVA-stimulated spleen cells, derived from Brown Norway rats, were strongly inhibited by A77 1726, leflunomide's active metabolite. When uridine was added to the cell culture, this molecule's effect on cell proliferation was completely restored, whereas the antibody production was partially restored. These findings are consistent with data indicating that leflunomide is a dihydroorotate dehydrogenase inhibitor. Taken together, the above findings suggest the therapeutic potential of leflunomide against type 1 allergic diseases.

Sequence analysis of small cryptic plasmids isolated from Selenomonas ruminantium S20

Two small cryptic plasmids designated pONE429 and pONE430 were isolated from a rumen bacterium, Selenomonas ruminantium S20. The complete sequence of pONE429 was 2100 bp and contained one open reading frame (ORF) of 201 amino acids. The sequence of pONE430 had 1527 bp and one ORF of 171 amino acids with the similarity of replication protein (Rep protein) of pOM1, pSN2, and pIM13 isolated from Butyrivibrio fibrisolvens, Staphylococcus aureus, and Bacillus subtilis, respectively. In these plasmids, the upstream nucleotide sequence of Rep protein had the conserved nucleotides which could be double-strand origin (DSO) of rolling circle replication (RCR) mechanism. The plasmids of pONE429, pONE430, pJJMI, pJDB21, and pS23 were isolated from S. ruminantium strains and had similar regions that were located within a <450-bp nucleotide. These similar regions may be the location that was recognized by the host strain, S. ruminantium.

Construction of Prevotella ruminicola-Escherichia coli shuttle vector pRAM45 and transformation of P. ruminicola strains by electroporation

A new plasmid shuttle vector, pRAM45, was constructed from the Escherichia coli plasmid pACYC184 and the cryptic plasmid pRAM4, which was originally isolated by us from Prevotella ruminicola T31 (Ogata et al., Plasmid, 35, 91-97, 1996). The vector was electrotransformed into different P. ruminicola strains. Polymerase chain reaction and Southern hybridization experiments confirmed its integrity in P. ruminicola transformants.

Os vesalianum as a cause of lateral foot pain: a familial case and its treatment

This is a rare case of bilateral symptomatic os vesalianum in a 13-year-old girl whose mother had the same condition unilaterally. We performed osteosynthesis and bone grafting instead of a simple resection to preserve the peroneus brevis tendon, with excellent results.

S-(1,2-Dicarboxyethyl)glutathione in yeast: partial purification of its synthesizing enzyme

S-(1,2-Dicarboxyethyl)glutathione (DCE-GS) was found in Saccharomyces cerevisiae, but not in bacterial species nor in a unicellular alga (Acetabularia acetabulum). The enzyme that catalyzes condensation of L-malate and glutathione (GSH) to form DCE-GS was partially purified from baker's yeast. It had a molecular mass of 49 kDa and was monomeric and the Km values were 2.2 and 1.4 mM for L-malate and GSH, respectively. The enzyme had a pH optimum of 7.5. DCE-GS levels in yeast cells were significantly higher in aerobic cultures than in anaerobic ones. DCE-GS was synthesized in cells cultured between 20 and 35 degrees C.

Mg2+ binding and catalytic function of sphingomyelinase from Bacillus cereus

The modes of Mg2+ binding to SMase from Bacillus cereus were studied on the basis of the changes in the tryptophyl fluorescence intensity. This enzyme was shown to possess at least two binding sites for Mg2+ with low and high affinities. The effects of Mg2+ binding on the enzymatic activity and structural stability of the enzyme molecule were also studied. The results indicated that the binding of Mg2+ to the low-affinity site was essential for the catalysis, but was independent of the substrate binding to the enzyme. It was also indicated that the alkaline denaturation of the enzyme was partly prevented by the Mg2+ binding, whereas no significant protective effect was observed against the denaturation by urea. The pH dependence of the kinetic parameters for the hydrolysis of micellar HNP and mixed micellar SM with Triton X-100 (1:10), catalyzed by SMase from B. cereus, was studied in the presence of a large amount of Mg2+ to saturate both the low- and high-affinity sites. The pH dependence curves of the logarithm of 1/Km for these two kinds of substrates were similar in shape to each other, and showed a single transition. On the other hand, the shapes of the pH dependence curves of the logarithm of kcat for these two kinds of substrates were different from each other. The pH dependence curve for micellar HNP showed three transitions and, counting from the acidic end of the pH region, the first and third transitions having tangent lines with slopes of +1 and -1, respectively. On the other hand, the curve for mixed micellar SM with Triton X-100 showed one large transition with a slope of +1 (the first transition) and a very small transition (the third transition). On the basis of the present results and the three-dimensional structure of bovine pancreatic DNase I, which has a primary structure similar to that of B. cereus SMase, we proposed a catalytic mechanism for B. cereus SMase based on general-base catalysis.

[An adult case of peripheral facial nerve palsy following acute cerebellitis associated with high antibody titers against varicella-zoster virus]

Here we report a case of acute cerebellitis, in which the patient developed right peripheral facial palsy during the recovery phase of cerebellar ataxia. A 67-year-old man developed truncal and limb ataxia following a fever, general fatigue and anorexia. He was diagnosed to have acute cerebellitis. While the ataxia symptoms were improving without any treatment, right peripheral facial nerve palsy developed and an MRI revealed an enhancement of the right facial nerve proximal to the geniculate ganglion. After treatment with acyclovir and corticosteroids, his facial nerve palsy and ataxia both gradually improved. There has been no previous report of an adult case who developed peripheral facial nerve palsy during the recovery phase of acute cerebellitis. This case indicates that a wide spectrum of neurological complications may develop in association with a varicella-zoster virus infection.

Clinical manifestations and immunodiagnosis of gnathostomiasis in Culiacan, Mexico

Gnathostomiasis was first described in Mexico in 1970, and endemic areas have been spreading in six states of this country. In Culiacan, Sinaloa, 300 cases of cutaneous larva migrans were recorded between January 1992 and December 1995. In addition, a Gnathostoma larva was surgically removed from the eye of one patient. Cutaneous lesions were observed mainly on the face, neck, arms, and legs. About 70% of the patients showed eosinophilia. A skin biopsy was carried out on 35 patients and the parasite was identified in histopathologic sections of 12 of these patients. In four patients, the larva migrated out spontaneously from the skin. An enzyme-linked immunosorbent assay using a crude somatic extract of adult Gnathostoma doloresi worms showed that 93% of the patients were seropositive, confirming the reliability of clinical diagnosis. A total of 14 advanced third-stage Gnathostoma larvae were found in four species of ichthyophagous birds captured on dams and dikes near the city of Culiacan. Scanning electron micrographs of human and bird larvae showed that they were morphologically indistinguishable from G. spinigerm. We conclude that the life cycle of Gnathostoma has been established in Sinaloa, and has become a serious public health issue for residents.

Plasma thrombopoietin (TPO) levels and expression of TPO receptor on platelets in patients with myelodysplastic syndromes

Data on endogenous thrombopoietin (TPO) levels and their regulation in myelodysplastic syndromes (MDS) are sparse. We examined the plasma TPO level of 85 MDS patients by a sensitive enzyme immunoassay and the platelet expression of TPO receptor (TPO-R) protein, which metabolizes endogenous TPO, in 19 MDS patients with an equilibrium binding assay using 125I-TPO. The MDS patients had higher plasma TPO levels (7.0 +/- 9.3 fmol/ml) than 52 normal subjects (P < 0.0001). Refractory anaemia (RA) patients (n = 39) had higher plasma TPO levels than patients (n = 28) with RA with excess blasts (RAEB) or RAEB in transformation (RAEB-t) (P = 0.0002), irrespective of similar platelet counts in these groups. The plasma TPO level correlated inversely with the platelet count in RA patients (P = 0.0027) but not in RAEB and RAEB-t patients (P = 0.7865). These data suggest that the physiological pathway for TPO production and metabolism is conserved, at least partially, in RA, but deranged in RAEB/RAEB-t. The number of TPO-R per platelet was significantly smaller in 19 MDS patients (17.5 +/- 13.3) than in normals (P = 0.0014), but similar between RA patients and patients with RAEB and RAEB-t. Further, the bone marrow megakaryocyte count, determined in 31 MDS patients, was quite similar between RA patients and patients with RAEB or RAEB-t. Thus, in addition to thrombocytopenia, a reduced platelet TPO-R number may contribute to elevated plasma TPO levels in MDS, and a regulatory pathway for circulating TPO other than platelet TPO-R and marrow megakaryocytes, such as blasts expressing TPO-R, may operate in RAEB/RAEB-t.

Crystal structure of methionine aminopeptidase from hyperthermophile, Pyrococcus furiosus

The structure of methionine aminopeptidase from hyperthermophile Pyrococcus furiosus (PfMAP) with an optimal growth temperature of 100 degreesC was determined by the multiple isomorphous replacement method and refined in three different crystal forms, one monoclinic and two hexagonal, at resolutions of 2.8, 2.9, and 3.5 A. The resolution of the monoclinic crystal form was extended to 1.75 A by water-mediated transformation to a low-humidity form, and the obtained diffraction data used for high-resolution structure refinement. This is the first description of a eukaryotic type methionine aminopeptidase structure. The PfMAP molecule is composed of two domains, a catalytic domain and an insertion domain, connected via two antiparallel beta-strands. The catalytic domain, which possesses an internal 2-fold symmetry and contains two cobalt ions in the active site, resembles the structure of a prokaryotic type MAP from Escherichia coli (EcMAP), while the structure of the insertion domain containing three helices has a novel fold and accounts for a major difference between the eukaryotic and prokaryotic types of methionine aminopeptidase. Analysis of the PfMAP structure in comparison with EcMAP and other mesophile proteins reveals several factors which may contribute to the hyperthermostability of PfMAP: (1) a significantly high number of hydrogen bonds and ion-pairs between side-chains of oppositely charged residues involved in the stabilization of helices; (2) an increased number of hydrogen bonds between the positively charged side-chain and neutral oxygen; (3) a larger number of buried water molecules involved in crosslinking the backbone atoms of sequentially separate segments; (4) stabilization of two antiparallel beta-strands connecting the two domains of the molecule by proline residues; (5) shortening of N and C-terminal tails and stabilization of the loop c3E by deletion of three residues.

Drill-hole guide for internal fixation of fractures of the mandibular condyle

We have developed a drill-hole guide valuable in accurately positioning the fracture of the mandibular ramus. It operates by introducing a Kirschner wire through the fracture stump from the mandibular angle to the condyle. A 2.0- to 2.4-mm-diameter Kirschner wire is drilled into the ramus from below and proceeds up to the condylar fragment through the stump of the fracture. With this guide, 15 patients with 23 subcondylar fractures underwent open reduction with Kirschner wire fixation. In each case, wire, by means of a pinning technique, was inserted accurately from the mandibular angle to the repositioned condyle.

Tissue factor is associated with the nonbacterial thrombotic endocarditis induced by a hypobaric hypoxic environment in rats

High-altitude hypoxia causes a hypercoagulable state. In our previous study on the blood coagulation system in rats, nonbacterial thrombotic endocarditis (NBTE) developed after 4-12 weeks' exposure to the equivalent of 5500 m in altitude. We hypothesized that TF (tissue factor)-producing cells in the cardiac valves might be induced by the hypobaric hypoxic environment (HHE) and then trigger NBTE. A total of 170 male Wistar rats were housed in a chamber at the equivalent of 5500 m altitude for 1-12 weeks. We measured TF activity in the plasma and studied morphological changes in the mitral valves using immunohistochemical and immunoelectrical methods for TF protein and in situ hybridization for TF mRNA. After 4 weeks or more of exposure to HHE, 28 of the 56 surviving rats had developed NBTE. After 4-8 weeks' exposure to HHE, the plasma TF activity level was significantly higher than in control rats. There was a significant correlation between plasma TF activity and the incidence of NBTE. After 1 weeks' exposure to HHE, immunoreactivity for TF protein was detected in foamy macrophages and stromal cells in the cardiac valves. In rats with NBTE, TF protein was present in foamy macrophages and spindle stromal cells and focally present in the extracellular matrix. TF mRNA was detected in some foamy macrophages within the thrombus, TF protein was localized to the rough endoplasmic reticulum and plasma membrane of many macrophages, some fibroblasts, and a few endocardial cells. TF is associated with the pathogenesis of the NBTE induced by exposure to HHE. The accumulation of TF-producing macrophages during exposure to HHE may be responsible for initiating thrombus formation.

Cloning, sequencing, and expression of an endoglucanase gene from the rumen anaerobic fungus Neocallimastix frontalis MCH3

A cDNA clone encoding an endo-1,4-beta-glucanase from a rumen fungus, Neocallimastix frontalis MCH3, was isolated. The nucleotide sequence showed that the gene, celA, encoded a multidomain enzyme containing a family 5 catalytic domain and a reiterated sequence that is involved in the association of a multienzyme complex, the cellulosome. The enzyme expressed in Escherichia coli showed the highest activity against carboxymethylcellulose at 40 degrees C and pH 8.5.

Repeated cycles of G-CSF-combined postremission chemotherapy for acute myeloid leukemia in a first complete remission: a pilot study

The cure rate of acute myeloid leukemia might increase if G-CSF were given concurrently with repeated postremission chemotherapy. However, this therapy might cause severe complications, including depletion of normal hematopoietic progenitors as a long-term toxicity. Thus, we conducted a pilot study of this strategy. Twenty-six acute myeloid leukemia patients in a first complete remission (CR) were treated with two courses of consolidation chemotherapy (10-day BHAC-DMP, consisting of behenoyl cytosine arabinoside, daunorubicin, 6-mercaptopurine and prednisolone) and repeated maintenance-intensification therapy including eight cycles of six-day BHAC-DMP. G-CSF (filgrastim) was administered concurrently with these BHAC-DMP therapies. Toxicity during the therapeutic period was not significant in the study group compared with the historical control, treated with the same regimen without G-CSF. Neutrophil recovery after the consolidation therapy was more rapid in the study group than in the historical control (p = 0.066 and 0.024 for the first and second consolidation courses, respectively). Long-term toxicity, such as cytopenia, has not been seen in eight patients who have remained in CR for a long period (range: 39-58 months). At a median follow-up of 39 months, the predicted rate of 42-month CR duration for these 26 patients was 50% (95% confidence limits: 30% to 71%). We conclude that G-CSF-combined repeated BHAC-DMP postremission therapy is feasible. Full elucidation of the clinical benefit of this strategy will require further study.

[Assessment of saphenous vein graft wall characteristics with intravascular ultrasound imaging]

The wall characteristics of saphenous vein grafts (SVGs) after coronary artery bypass grafting (CABG) were assessed with intravascular ultrasound (IVUS) imaging. Twenty-seven SVGs in 25 patients who had undergone CABG were studied with IVUS in vivo. Ten SVGs excised from 6 patients who had undergone reoperation were studied with IVUS in vitro. The results were compared with the histopathologic findings. IVUS images of four SVGs studied within 1 month after CABG showed a thin and single-layer structure, which was almost identical to the IVUS features of a normal, fresh SVG. In five SVGs studied between 3 months and 1 year after CABG, the wall thickness was increased, and there were hypoechoic areas. In sixteen SVGs studied more than 2 years after CABG, two patterns were noted on IVUS imaging. One pattern was a triple-layer structure of alternating hyperechoic, hypoechoic, and hyperechoic bands seen in the angiographically normal sections of the SVGs. The second pattern was a heterogeneous, echogenic monolayer found in the angiographically irregular and diseased sections of the SVGs. Comparison of the in vitro IVUS images with the histopathology of the SVGs showed a strong correlation between the triple-layer structure and fibrointimal proliferation, and between the heterogeneous monolayer and atherosclerosis. In conclusion, IVUS is useful for assessing SVGs and for long-term qualitative monitoring of vein graft disease after CABG.

[Treatment of nocturnal periodic hypoxemia with safrazine hydrochloride in a patient with Duchenne muscular dystrophy under nasal intermittent positive pressure ventilation]

Nocturnal periodic hypoxemia occurring in a 25-year-old Duchenne muscular dystrophy patient under NIPPV control was successfully treated with monoamine oxydase inhibitor (MAOI), safrazine hydrochloride. Five mg of safrazine hydrochloride was administered before sleep, and the periodic hypoxemia disappeared within 14 days. The effect lasted almost seven months without notable side effect. MAOI may be effective for nocturnal hypoventilation through suppression of REM sleep as in the case of tricyclic antidepressants. The effect of tricyclic antidepressants appears immediately. However, it usually fades away within forty days. Safrazine hydrochloride was effective obviously longer than tricyclic antidepressants. Consequently MAOI may be a hopeful candidate of medication for a treatment of nocturnal periodic hypoxemia in Duchenne muscular dystrophy.

[Successful management of aorto-esophageal fistula due to rupture of thoracic aortic aneurysm in an elderly patient]

Aorto-esophageal fistula due to ruptured thoracic aortic aneurysm is very rare but is associated with extremely high mortality. An 81-year-old woman was admitted due to repeated hematemesis. Endoscopic examination revealed ulceration with blood clot on the mid-esophagus and compression of an extra-esophageal mass. The thoracic CT scan revealed an aorto-esophageal fistula due to a ruptured descending thoracic aortic aneurysm. Surgery was performed on April 3, 1996. We report an aorto-esophageal fistula managed successfully in one stage by resection and replacement of the aortic aneurysm with a prosthetic graft and total esophageal resection. The esophagus was reconstructed using orthotopic gastric interposition with omentopexy around the prosthetic aortic graft. The postoperative course was uneventful and there have been no signs of mediastinal sepsis, graft infection or pyothorax 12 months postoperatively. We suggest that the resection of both the aneurysm and the esophagus as well as the immediate reconstruction of the esophagus by orthotopic gastric interposition to obliterate the retrosternal space are important technique in the management of intrathoracic infections.

[Somatic mosaicism of p(CTG)n expansion in a case of myotonic dystrophy with parotid tumor]

Myotonic dystrophy (MD) is an autosomal dominant systemic disorder with an unstable expansion of the CTG triplet repeat in the 3'-untranslated region of the gene encoding myotonine protein kinase (DMPK) which maps to chromosome 19q13.3. Somatic mosaicism of CTG repeats in MD has been reported; and it has been observed that CTG repeats in tumor tissues associated with MD are more expanded than the other tissues. It is not rare that parotid tumors are found in patients with MD. We performed Southern blot analysis for tissues from the parotid tumor, the normal parotid gland, the skeletal muscles, and the leukocyte from a 60-year-old patient with MD. CTG repeat was most expanded in the parotid tumor, and the normal parotid gland had longer expansion of CTG repeat than the skeletal muscles. The leukocyte had the shortest expansion of CTG repeat. The expansion of CTG repeat in the parotid tumor may be related to active cell division and may underlie the occurrence of tumors in MD.

Amino acid similarity matrix for homology modeling derived from structural alignment and optimized by the Monte Carlo method

In this paper, we obtained a similarity matrix for homology modeling based on the structure of proteins in a structural alignment. The alignment procedure was executed within dynamic programming generally used in alignment methods. An initial matrix derived from the structural alignment was optimized by the Markov chain Monte Carlo method at low temperature to fit its sequence alignment to the structural alignment. Structural alignment was performed on the basis of the superposition of C alpha atoms for two protein structures. The objective function in the Monte Carlo procedure was defined by entropy in the information theory, allowing us to show that the amino acid similarity matrix aligned accurately. When compared with the structural alignment, the average number of incorrect amino acid residues in the sequence alignment was 22.6 for all residues and about 3.7 for residues in structurally conserved regions. The alignment with our matrix was more similar to structural alignment than to sequence alignments using other amino acid substitution matrices.

Current status of gnathostomiasis dorolesi in Miyazaki Prefecture, Japan

Gnathostomiasis is an important food-borne parasitic zoonosis caused mainly by ingesting uncooked or undercooked flesh of freshwater fishes. Although four distinct species of the genus Gnathostoma were identified as the causative agents for human gnathostomiasis, human infections with G. doloresi have been found only in Japan, concentrated in Miyazaki Prefecture. So far we have found 25 cases in Miyazaki Prefecture. Although most of these patients were of cutaneous gnathostomiasis, two patients presented to the hospital with unusual clinical manifestations; one case was a pulmonary gnathostomiasis diagnosed by immunoserological methods, and the other was an ileus caused by migration of the late 3rd stage larva in the colonic tissue, which was found by post-operative histopathological examination. Although cutaneous lesions such as creeping eruption or mobile erythema are the common clinical features of gnathostomiasis, caution should be paid to the presence of such unusual cases.

Reappraisal of the expression of mast cell proteases of Mongolian gerbils (Meriones unguiculatus)

Mast cell proteases in the tongue and jejunum of Mongolian gerbils (Meriones unguiculatus) were examined by enzyme-histochemical methods. Both trypsin-like (tryptase) and chymotrypsin-like (chymase) protease activities were demonstrated in mast cells in the tongue of fresh cryosections. When frozen sections of the tongue were post-fixed in various fixatives, those fixed in Carnoy's fluid showed strongest enzyme activities. Tryptase and chymase activities in paraffin sections of both tissues were well preserved when tissues were fixed in Carnoy's fluid at 4 degrees C for 15 min. However, enzyme activities in both tissues, especially in the tongue, were drastically reduced by longer fixation time and higher temperature. When Carnoy-fixed (4 degrees C for 15 min) paraffin sections were treated with heparinase I or chondroitinase ABC before enzyme-histochemical stainings for proteases, tryptase activities were lost entirely in the tongue and mostly in the jejunum by heparinase I digestion, and slightly in both organs by chondroitinase ABC digestion. In contrast, chymase activities at both sites were not influenced by these pretreatments. These results show that although mast cells in the tongue as well as in the jejunum of Mongolian gerbils contain both tryptase and chymase activities, their stability to fixations is variable among organs so that tissue fixation conditions are crucial for the preservation. At least some part of the stability of mast cell proteases is dependent on the proteoglycans present in mast cell granules.

Effect of EPC-K1 on myocardial infarct size in a rat model with coronary artery occlusion and reperfusion

1. The ability of EPC-K1 to improve myocardial infarction was evaluated in a rat model with coronary artery occlusion and reperfusion. 2. The myocardial infarct size was 30.5 +/- 1.7% by intravenous (i.v.) administration and 28.8 +/- 2.7% by intraduodenal (i.d.) administration of the saline EPC-K1 at doses between 1 and 10 mg/kg, i.v. and at doses between 50 and 200 mg/kg, i.d., reduced myocardial infarct size dose dependently. Significant reduction in myocardial infarct size was found at a dose of 10 mg/kg, i.v., and 200 mg/kg, i.d.

Pulmonary toxicity after granulocyte colony-stimulating factor-combined chemotherapy for non-Hodgkin's lymphoma

Sporadic cases have developed pulmonary toxicity after receiving chemotherapy and granulocyte colony-stimulating factor (G-CSF). However, because such cases received chemotherapy that alone frequently causes pulmonary toxicity, the role of G-CSF in this toxicity has been unclear. CHOP therapy (cyclophosphamide, doxorubicin, vincristine and prednisolone) only slightly induces pulmonary toxicity. However, we observed a considerable incidence of this toxicity in non-Hodgkin's lymphoma subjects receiving CHOP therapy and G-CSF (6 out of 52 subjects, 11.5%). In this cohort, among various characteristics, including the dose and interval of CHOP therapy, only the mean peak leucocyte count (MPLC) with each therapy cycle was associated with development of this toxicity (MPLC > or = 23.0 x 10(9) l(-1), 6 out of 29 cases; MPLC < 23.0 x 10(9) l(-1), 0 out of 23 cases; P = 0.020). These findings suggest that the effect of G-CSF is the main determinant of the pulmonary toxicity in these cases. Because the toxicity was associated with a large MPLC and did not recur in cases readministered G-CSF, an idiosyncratic reaction to G-CSF is unlikely to be the pathogenesis of this toxicity. Thus, lowering the G-CSF dose seems to be useful in the prevention of this toxicity. In all six cases, the time course of manifestation of the toxicity was the same, and early application of high-dose corticosteroid led to cure. This knowledge will be helpful in the care of similar cases.

The role played by environmental residues on sidechain torsional angles within homologous families of proteins: a new method of sidechain modeling

We investigated the conservation of sidechain conformation for each residue within a homologous family of proteins in the Protein Data Bank (PDB) and performed sidechain modeling using this information. The information was represented by the probability of conserved sidechain torsional angles obtained from many families of proteins, and these were calculated for a pair of residues at topologically equivalent positions as a result of structural alignment. Probabilities were obtained for a pair of same amino acids and for a pair of different amino acids. The correlation between environmental residues and the fluctuation of probability was examined for the pair of same amino acid residues, and the simple probability was calculated for the pair of different amino acids. From the results on the same amino acid pairs, 17 amino acids, except for Ala, Gly, and Pro, were divided into two types: those that were influenced and those that were not influenced by the environmental residues. From results on different amino acid pairs, a replacement between large residues, such as Trp, Phe, and Tyr, was performed assuming conservation of their torsional angles within a homologous family of proteins. We performed sidechain modeling for 11 known proteins from their native and modeled backbones, respectively. With the native backbones, the percentage of the chi 1 angle correct within 30 degrees was found to be 67% and 80% for all and core residues, respectively. With the modeled backbones, the percentage of the correct chi 1 angle was found to be 60% and 72% for all and core residues, respectively. To estimate an upper limit on the accuracy for predicting sidechain conformations, we investigated the probability of conserved sidechain torsional angles for highly similar proteins having > 90% sequence identity and < 2.5-A X-ray resolution. In those proteins, 83% of the sidechain conformations were conserved for the chi 1 angle.

Lymphoblastic lymphoma of natural killer cell origin, presenting as pancreatic tumour

AIMS

We describe the first case of lymphoblastic lymphoma (LBL) of natural killer (NK) cell origin initially presenting as a pancreatic tumour, and review this type of lymphoma.

METHODS AND RESULTS

A 38-year-old woman with abdominal pain was found to have a pancreatic mass. Twenty days later, she developed diffuse lung infiltrates and leucoerythroblastosis of the peripheral blood, and her bone marrow was diffusely infiltrated with blasts. The blasts were positive for CD56, CD16 and P-glycoprotein, but lacked cytoplasmic azurophilic granules, T. B and myeloid cell markers on the cell surface, rearrangement of the genes for T-cell receptor and immunoglobulin, and the Epstein-Barr virus (EBV) genome. The diagnosis was LBL of NK cell origin. She received aggressive therapy, but died of the lymphoma. In contrast to ordinary NK-cell lymphoma, this case and reported cases of LBL of NK-cell origin showed the following common characteristics. The tumour cells often lack cell surface CD2, cytoplasmic CD3, cytoplasmic azurophilic granules, and EBV genome. The prognosis was extremely poor.

CONCLUSIONS

LBL of NK-cell origin should be included in the differential diagnosis of pancreatic tumours. To fully characterize this type of lymphoma, further cases must be evaluated.

Transcriptional regulation of the Prevotella ruminicola recA gene

The regulation of the recA gene expression in the obligately anaerobic rumen bacterium Prevotella ruminicola was investigated by monitoring the recA-specific transcript level. P. ruminicola recA forms a monocistronic unit, but no SOS-box sequences resembling those of Escherichia coli or Bacillus subtilis can be identified upstream of the recA coding region. At the same time, we observed a fivefold increase in the level of recA mRNA in response to DNA damaging agents, mitomycin C and methyl methanesulfonate, as well as under conditions of oxidative stress. No induction was detected when growth of P. ruminicola was arrested by shifting to acidic (pH 4.8) conditions. Primer extension experiment revealed the three very close transcriptional start sites for recA. The putative -10 and -35 RNA polymerase binding regions were proposed on the basis of transcript mapping. These regions bear very little similarity to the E. coli (sigma70) and B. subtilis (sigmaA) consensus sequences, as well as to the recognition sites of other minor sigma-factors. Transcript mapping experiments in E. coli expressing P. ruminicola recA confirmed that the transcription machineries of these two bacteria recognize completely different regulatory sequences on the template to initiate transcription. Preliminary DNase I footprinting analysis data revealed that the region of imperfect dyad symmetry (AATTATAATCAATTATAAAT) found between the putative -10 region and the translation initiation codon may serve as an SOS-box-like regulatory sequence in P. ruminicola. This sequence bears no similarity to the known SOS-box sequences and, in particular, to that of E. coli and other Gram-negative bacteria.

Phase II trial of combination chemotherapy with cisplatin, carboplatin and etoposide in stage IIIB and IV small-cell lung cancer. Fukuoka Lung Cancer Study Group

PURPOSE

A phase II trial combining cisplatin, carboplatin and etoposide was conducted in previously untreated patients with stage IIIB and IV small-cell lung cancer, in an attempt to increase response rates and prolong survival.

METHODS

Previously untreated patients with small-cell lung cancer, with measurable disease, aged < or = 72 years, performance status < or = 2, and adequate hematologic, hepatic and renal function were enrolled in the study. They were treated with 80 mg/m2 cisplatin on day 1, 100 mg/m2 carboplatin on days 2, 3 and 8, and 50 mg/m2 etoposide on days 1, 2, 3 and 8.

RESULTS

A total of 46 patients (20 with stage IIIB and 26 with stage IV disease) were enrolled in the study. A total of 186 courses of chemotherapy were given, and the dose was reduced in 27 courses (15%). The chemotherapy was repeated for four or more courses in 30 patients. There were 10 complete responses and 32 partial responses, for a total response rate of 91% (95% confidence interval, 79% to 98%). The median survival time and 2-year survival rates were 18 months and 22% for stage IIIB disease, and 14 months and 15% for stage IV disease. Major side effects were hematologic: leukopenia, anemia, and thrombocytopenia of grade 3 or more occurred in 48%, 46%, and 43% of patients, respectively.

CONCLUSIONS

The three-drug regimen of cisplatin, carboplatin and etoposide is feasible and active against small-cell lung cancer.