Safety of tapering tacrolimus dose in patients with well-controlled anti-acetylcholine receptor antibody-positive myasthenia gravis.

BACKGROUND AND PURPOSE: Tapering immunosuppressants is desirable in patients with well-controlled myasthenia gravis (MG). However, the association between tapering of calcineurin inhibitor dosage and reduction-associated exacerbation is not known. The aim of this study was to clarify the frequency of reduction-associated exacerbation when tacrolimus is tapered in stable patients with anti-acetylcholine receptor antibody-positive MG, and to determine the factors that predict exacerbations. METHODS: We retrospectively analyzed 115 patients in whom tacrolimus dosage was tapered. The reduction-associated exacerbation was defined as the appearance or worsening of one or more MG symptoms <3 months after the reduction. RESULTS: Tacrolimus dosage was successfully tapered in 110 patients (96%) without any exacerbation. Five patients (4%) experienced an exacerbation, but symptoms were reversed in all patients when the tacrolimus dose was increased to the previous maintenance level. No patient developed an MG crisis. The age at onset was significantly earlier (30 vs. 56 years, P = 0.025) and the reduction in dosage was significantly larger (2.0 vs. 1.0 mg/day, P = 0.002) in patients with reduction-associated exacerbation than in those without exacerbation. The cut-off values determined in a receiver-operating characteristic curve analysis were 52 years (sensitivity, 57%; specificity, 100%) for the age at onset and 1.5 mg (sensitivity, 80%; specificity, 100%) for the dose reduction. CONCLUSION: Tapering of tacrolimus was possible in most patients with well-controlled anti-acetylcholine receptor antibody-positive MG. Early age at onset and a large reduction from maintenance dosage were associated with exacerbation. Reductions ≤1.5 mg/day from the maintenance dosage should be considered for patients with late-onset disease.

Spinal cord ring enhancement in patients with neuromyelitis optica.

OBJECTIVES: Clinical and pathological significance of gadolinium (Gd)-enhancing pattern on magnetic resonance imaging (MRI), including ring enhancement (RE), is well documented in multiple sclerosis but not in neuromyelitis optica (NMO), especially in the spinal cord. The purpose of this study is to examine the prevalence of spinal cord RE in NMO and to determine the association between clinical characteristics and spinal cord RE. MATERIALS AND METHODS: We retrospectively examined Gd-enhanced spinal cord MRI scans, during the acute phase, in patients with anti-aquaporin 4-positive NMO, including NMO spectrum disorder. We then analysed their clinical features and MRI imaging characteristics of spinal cord lesions. RESULTS: Of the 30 patients with NMO, we enrolled 12 patients with 16 Gd-enhanced spinal cord MRI scans in this study. Five scans revealed RE (31.2%). Male ratio, as well as myelin basic protein (MBP) levels, in the cerebrospinal fluid (CSF) of patients with RE was significantly higher than those of patients without RE (P = 0.018, P = 0.026, respectively). CONCLUSIONS: Spinal cord RE is common in patients with NMO. Higher MBP levels in the CSF of patients with RE can be associated with a higher degree of myelin damage.

Inverse correlation between expression of multidrug resistance gene and N-myc oncogene in human neuroblastomas.

Genomic amplification of N-myc is an important prognostic indicator in neuroblastoma. The tumors with amplified N-myc are initially sensitive to chemotherapy but often acquire resistance to therapy, recur, and ultimately kill the patients. We measured amplification and expression of N-myc and expression of mdr-1 in 35 surgically resected neuroblastomas, before acquisition of drug resistance and in 4 recurrent tumors resistant to chemotherapy. The mdr-1 mRNA expression was found to be inversely correlated with the N-myc expression. The mdr-1 gene expression was at a low level in advanced stage and histologically undifferentiated neuroblastomas, the same group of tumors in which N-myc expression is elevated. A significantly better prognosis was noted in those patients whose tumors had a high level of mdr-1 expression and a low level of N-myc expression. The role, if any, of increased expression of mdr-1 in the acquisition of multidrug resistance in neuroblastoma remains unclear. However, the aggressive clinical behavior associated with N-myc amplification and/or expression appears to be linked to down-regulation of mdr-1 expression.

Inhibition of thiamine transport in anaerobic baker's yeast by iodoacetate, 2,4-dinitrophenol N,N'-dicyclohexylcarbodiimide and fatty acids.

1. [14C]Thiamine uptake by baker's yeast (Saccharomyces cerevisiae) was strongly inhibited by 0.2 mM iodoacetate, 0.2 mM 2,4-dinitrophenol and 0.1 mM N,N'-dicyclohexylcarbodiimide under anaerobic conditions. 2. The inhibition of anaerobic [14C]thiamine uptake by these inhibitors was accompanied by almost parallel decreases in the ATP level of the yeast cells. 3. On the other hand, the short-chain fatty acids inhibited [14C]thiamine uptake to a large extent, without greatly affecting the intracellular ATP level. This suggests that the acids primarily block the use of energy from ATP for the transport rather than the fermentation process. 4. Caproate, which has a most pronounced inhibitory effect on [14C]thiamine uptake, significantly prevented the dissipation of an energized membrane state of yeast cells necessary for the active transport of thiamine. 5. Possible ways in which the inhibitors may affect thiamine uptake were discussed.

Affinity chromatography of thiamin pyrophosphokinase of rat brain.

Affinity column chromatography coupled with thiamin monophosphate absorbs thiamin pyrophosphokinase activity in the crude extract of rat brain, and the enzyme can be eluted from the column by 0.01 mM thiamin with approximately 700-fold purification.

Circulating immune complexes in rheumatoid arthritis. Selective removal by cryogelation with membrane filtration.

We have developed a system of extracorporeal circulation that removes proteins of the molecular weight of the circulating immune complexes of rheumatoid arthritis by cryogelation with hollow-fiber membrane filtration. A 52-year-old woman with a 36-year history of severe, unremitting, high-titer, seropositive rheumatoid arthritis who had failed to respond to anti-inflammatory, antirheumatic, and cytotoxic drugs was chosen for a trial of this system. A rapid and sustained decrease in circulating immune complexes as measured by C1q binding occurred, accompanied by a much slower improvement in clinical factors of disease activity. Rheumatoid factor changed very little and loss of other serum proteins by the procedure was relatively modest. This new procedure was successful in removing circulating immune complexes in a patient with rheumatoid arthritis, and in inducing a remission in one who has not had such in 36 years, while sparing volume and other plasma proteins.

Human leukocyte antigen-A24 and -DQA1*0301 in Japanese insulin-dependent diabetes mellitus: independent contributions to susceptibility to the disease and additive contributions to acceleration of beta-cell destruction.

The aim of this study is to identify insulin-dependent diabetes mellitus (IDDM)-susceptible HLA antigens in IDDM patients who do not have established risk allele, HLA-DQA1*0301, and analyze relationship of these HLA antigens and the degree of beta-cell destruction. In 139 Japanese IDDM patients and 158 normal controls, HLA-A, -C, -B, -DR and -DQ antigens were typed. Serum C-peptide immunoreactivity response (deltaCPR) to a 100-g oral glucose load < or = 0.033 nmol/l was regarded as complete beta-cell destruction. All 14 patients without HLA-DQA1*0301 had HLA-A24, whereas only 35 of 58 (60.3%) normal controls without HLA-DQA1*0301 and only 72 of 125 (57.6%) IDDM patients with HLA-DQA1*0301 had this antigen (Pc = 0.0256 and Pc = 0.0080, respectively). DeltaCPR in IDDM patients with both HLA-DQA1*0301 and HLA-A24 (0.097 +/- 0.163 nmol/L, mean +/- SD, n = 65) were lower than in IDDM patients with HLA-DQA1*0301 only (0.219 +/- 0.237 nmol/L, n = 45, P < 0.0001) and in IDDM patients with HLA-A24 only (0.187 +/- 0.198 nmol/L, n = 14, P = 0.0395). These results indicate that both HLA-DQA1*0301 and HLA-A24 contribute susceptibility to IDDM independently and accelerate beta-cell destruction in an additive manner.

Biomodulation effects of extracorporeal circulation in apheresis.

The association of biochemical and cellular abnormalities in various disease states provides the rationale for apheresis technologies. Plasmapheresis by plasma exchange has severe technical and clinical limitations due to the nonselective removal of plasma factors. Plasmapheresis methods for the more selective removal of plasma components include membrane filtration, sorption, and physico-chemical methods such as precipitation. These methods can also eliminate the need for plasma product replacement and be more specific to the clinical needs. While plasmapheresis technologies are designed primarily for solute removal, the methodology itself will have a biomodulating influence and will impact on the course of the disease state. Extracorporeal biomodulation is defined as the act of effecting changes either procedurally induced or procedurally associated in the cellular or biochemical milieu of the body. Factors to be considered in an extracorporeal procedure such as plasmapheresis include the duration of an individual treatment, the degree of solute removal selectivity, the prescribed frequency for the treatment, the type of equipment employed, the choice of anticoagulant, and the materials for blood and plasma contact. Thus, the modulatory effects of the methodology occur not only in the humoral system but also among the cells. The effects of the modulation will extend beyond the procedure time. The general direction in material research for extracorporeal circulation is to minimize the biological response. However, the modulating effects of the procedure, independent of the removal effects, suggest that the proper choice of materials in the extracorporeal circuit can benefit the patient. With the various techniques of solute removal and material availability, the clinician may chose the biomodulating system for the treatment of a given disease state.

Therapeutic trial of cryofiltration in patients with rheumatoid arthritis.

Cryofiltration, a new technique for on-line plasma separation and its treatment by cold filtration, enables the selective removal of immune complexes and eliminates the need for replacement proteins. Fifteen patients with rheumatoid arthritis were treated for nine to 10 consecutive sessions over a three- to five-week period. Circulating immune complexes decreased by an average of 78 percent and rheumatoid factor by 32 percent. This was accompanied by significant clinical improvement in morning stiffness, articular index, 50-foot walking time, grip strength, and target joint circumference. Cryofiltration might thus be beneficial for a subgroup of rheumatoid arthritis patients in whom conventional therapy has failed.

A new HLA-DP (SB) specificity (Cp63) defined in Japanese and Caucasian cell populations by cloned PLT cells.

Cp61, Cp62, and Cp63 are HLA-DP (SB) specificities detected by PLT testing using cloned PLT cells derived from Japanese cell donors. It was confirmed, using Japanese and Caucasian cell panels, that Cp61 is identical to DPw5 and Cp62 is identical to DPw4. Cp63, however, was found not to correlate with any known HLA-DP specificities. The gene frequency of Cp63 was found to be 3.6% in Japanese (N = 42) and 1.9% in Caucasian (N = 52) cell panels of limited size. No triplet assignment of DPw specificity including Cp63 was found in the Japanese and Caucasian cell populations. The relationship between the Cp63 and the HLA antigens demonstrated no significant correlation with HLA-A,B,C,DR, or MT antigens in this study. Linkage between Cp63 and HLA was confirmed from family segregation studies. This is the first report of a new DP specificity termed Cp63.

Sequence variation in Japanese HLA-DRw8 specificity.

There are four DRw8 haplotypes with different DQ alleles in Japanese: DRw8-DQw6 (w1), DRw8-DQw4, DRw8-DQw8(w3), and DRw8-DQw7 (w3). We previously reported the nucleotide sequence of DRB1 gene of DRw8-DQw6(w1) and it was named DRB1*08032. The nucleotide sequences of the other DRw8 DRB1 alleles and their correspondence to internationally recognized DRw8 subspecificities were still unclear. We have cloned these DRB1 genes and determined the nucleotide sequences. The comparison of the sequences with the published sequences revealed that the differences were occurred at two amino acid positions, and these four haplotypes are classified in two groups: (a) DRw8-DQw6(w1) and DRw8-DQw7(w3), and (b) DRw8-DQw4 and DRw8-DQw8(w3). The DRB1 molecules of DRw8-DQw6(w1) and DRw8-DQw7(w3) have Ser57 and Ile67, and those of DRw8-DQw4 and DRw8-DQw8(w3) have Asp57 and Phe67. The former has the same sequence as that of DRB1*08032, and the latter is same as that of DRB1*0802. The classification corresponds to the serologic subtyping, which divides DRw8 into DR8.1 and DR8.2, reported in the 10th Japan HLA Workshop.

HLA-D clusters associated with DR4 in the Japanese population.

A study of HLA-D clusters associated with DR4 was performed in the Japanese population. These clusters consist of DYT, DKT2, DB3, and Dw4. Forty-two Japanese typed as DR4 were investigated, and it was found that 17 (40.5%) were DYT, 7 (16.7%) DKT2, 7 (16.7%) DB3, and 4 (9.5%) Dw4.

Analysis of HLA-DM polymorphisms in sarcoidosis.

Sarcoidosis is a multisystemic granulomatous disorder showing significant increases in the HLA-DRB1*11, *12, *14 and *08 alleles in the Japanese population. To evaluate the role of polymorphism in the DMA and DMB genes in predisposition to sarcoidosis, seventy Japanese patients with sarcoidosis and 95 unrelated healthy controls were analyzed in the third exon polymorphisms within the DMA and DMB genes by the PCR-RFLP method. There were no differences in the distribution of DMA alleles between the patient and control groups. The frequency of DMB*0102 was higher (p < 0.05) and that of DMB*0101 was lower (p < 0.05) in the patients than in the healthy controls. However, this association and negative association could be explained by linkage disequilibrium with the disease-associated DRB1 alleles. The DMA and DMB genes do not primarily confer the susceptibility to sarcoidosis.

Cloned primed lymphocyte test cells recognize the fourth, fifth, and sixth hypervariable regions at amino acid positions 65-87 of the DPB1 molecule.

Genetic polymorphisms of the HLA-DPB1 gene in Japanese and Caucasian panel cells defined by PLT were analyzed by the PCR-based genotyping technique PCR-RFLP, and suballeles of DPw3 (DPB1*03) and DP"Cp63" (DPB1*09) could be detected. PLT-defined DPw3 cells were typed by PCR-RFLP as either DPB1*0301 or DPB1*1401. On the other hand, PLT-defined DPCp63-typed cells were typed as DPB1*0901 or DPB1*1001. These results indicate that both DPw3 and DPCp63 are split into two subantigens. DPw2 and DPw4 are DPB1*0201 and 0202 and DPB1*0401 and 0402, respectively. Comparative analysis of the amino acid sequences of the DPw2-, DPw4-, DPw3-, and DPCp63-associated alleles revealed that the fourth (C), fifth (D), and sixth (E) hypervariable regions at amino acid positions 65-87 were shared within the same PLT-defined DP antigen groups, suggesting that these three hypervariable regions are recognized by cloned T cells in PLT, thus determining DP antigen specificity. On the basis of this model, 44 DPB1 alleles can be classified into 18 antigen groups, each of which may possibly represent a PLT-defined single DP specificity.

Cloning of cDNA for vitellogenin of the parasitoid wasp, Pimpla nipponica (Hymenoptera: Apocrita: Ichneumonidae): vitellogenin primary structure and evolutionary considerations.

The cDNA for vitellogenin (Vg) of the parasitoid wasp Pimpla nipponica (Hymenoptera: Apocrita) was cloned and sequenced. The deduced amino acid sequence with 1807 residues was obtained. The N-terminal 20 amino acids chemically determined for vitellin (Vn) agreed completely with the deduced 20 amino acids that follow the 16 amino acid residues for putative signal peptide. The cDNA clone for the Vg of the turnip sawfly Athalia rosae (Hymenoptera: Symphyta), previously obtained and partially sequenced, was also completely sequenced and the amino acid sequence deduced. Amino acid sequences were compared between these two species and also with known Vg sequences from other insects. Common to all these insects is the presence of two long regions with relatively well-conserved amino acid sequences, one near the N-terminal extending 267-282 residues (including two cysteines at conserved locations), and the other starting at position 450 to 655 and extending 279-283 residues, and of a region at the C-terminal extending some 200 residues (about 250 in Aedes aegypti due to the presence of a serine-rich stretch) with 10 cysteines at conserved locations. A molecular phylogenetic tree was constructed.

Physiological effects of modified hemoglobin as an oxygen-carrying macromolecule.

A stabilized hemoglobin as oxygen-carrying macromolecules was developed. It had approximately 90,000 dalton molecular weights and its intravascular half life was 36 hours. Its molecular size was less than 0.1 micron. Its hemoglobin concentration was 6% and P50 value was 24 mmHg. The oxygen carried inside the plasma performs differently than the oxygen carried inside the red cells. Only less than 0.3 ml of oxygen in 100 ml of blood is available inside the plasma while 14-19 ml of oxygen is carried inside the red cells. Thus, less than 5 ml of oxygen is available inside the plasma of the entire body. When a patient develops hypovolemic shock, the red cells are bypassed and are not perfused directly inside the tissues. However, the plasma should reach such hypoxic tissues. Thus, infusion of oxygen-carrying macromolecules in the plasma should be therapeutically effective even if less than 100 ml of stabilized hemoglobin solution were infused under shock conditions. The basic physiology of oxygen-carrying macromolecules is described in detail, which is different from the oxygen carried inside the red cells.

Outbreak of multi-drug resistant Staphylococcus aureus: a cluster analysis.

BACKGROUND: Outbreaks of multi-drug resistant Staphylococcus aureus over eight years were investigated to prevent future endemic. METHODS: Isolates of multiresistant S. aureus underwent a cluster analysis combined with canonical discriminant analysis using bacteriologic biotyping and sensitivity to 21 drugs. RESULTS: Of a total of 786 strains recovered from 155 in-patients, the specialty surgical ward (SW) exhibited 470 isolates (59.8%) and the general SW 214 (27.2%). Among six clusters formed, four clusters were predominant in the general SW. An ordination diagram from the canonical discriminant analysis revealed a distribution in which clusters were localized temporally (year) and spatially (ward). A yearly shift of clusters indicated emergence of a new phenotype of multiresistant S. aureus. CONCLUSIONS: The cluster analysis of isolates of multiresistant S. aureus using biotyping and sensitivity may supplement the classical method of tracing the spreading patterns of this microbe.

The effect of extraanatomic bypass on aortic input impedance studied in open chest dogs. Should the vascular prosthesis be compliant to unload the left ventricle?

Left ventricular hypertrophy has been reported after ascending aorta-abdominal aorta bypass, despite seemingly insignificant changes in cardiac output and mean arterial pressure. Such a bypass procedure may be used for the treatment of complex coarctation of the aorta, hypoplastic aortic arch, or thoracoabdominal aortic aneurysm. To investigate the effect of the bypass procedure on left ventricular afterload, we measured aortic input impedance in six open chest dogs by placing a knitted Dacron graft from the ascending aorta to the abdominal aorta and occluding the aortic arch. Cardiac output and mean arterial pressure remained unaltered throughout the experiment, consistent with clinical reports. Systolic pressure increased by 25% of control, and the ratio of diastolic pressure-time index to tension-time index decreased by 27%. The measured input impedance was then approximated with the three-element windkessel model, which consists of resistance, compliance, and characteristic impedance (average of impedance modulus between 5 and 15 Hz). There was no change in resistance and compliance; characteristic impedance increased to 255% of control. Connecting an air chamber to the vascular prosthesis doubled the compliance and decreased the characteristic impedance nearly to the control value without altering resistance. It also reduced the systolic pressure by 14% of the bypass protocol and increased the ratio of diastolic pressure-time index to tension-time index (by 32% of control value and 82% of bypass value). Arterial systolic pressure and pulse pressure were both linearly correlated with the characteristic impedance. Thus we conclude that although ascending aorta-abdominal aorta bypass does not affect cardiac output, mean arterial pressure, resistance, or compliance, it does increase characteristic impedance. Left ventricular systolic load is directly correlated with characteristic impedance. Increased systolic wall stress might be the cause of left ventricular hypertrophy of the previously reported cases. Because decrease in the distensibility of the proximal aorta is one of the factors causing the increase in characteristic impedance, using a compliant graft might help to unload the heart.

Survival for 145 days with a total artificial heart.

A calf into which a biolized, total artificial heart (TAH) had been implanted survived for 145 days. All measured physiological parameters except central venous pressure (CVP) were back to normal one month after implantation, and thereafter the animal's physiological development was similar to that of a normal calf. The intimal weight, which was 96 kilograms at implantation, reached 190 kilogram at the end of experiment, with a daily gain rate of 0.9 kilogram per day. After the nineteenth postoperative week, signs of congestive heart failure appeared, such as high venous pressure, ascites, and enlarged liver although the calf outwardly appeared well. On postoperative day 146, the animal started foaming at the mouth, and a convulsion occurred; then, the experiment was terminated after 3,494 hours of pumping. At autopsy, there were acute bilateral bronchopneumonia involving mostly both upper lobes, pulmonary edema, slight chronic pneumonitis, and hepatomegaly. There were no serious thrombotic deposits inside the cardiac prosthesis.

Clinical results of mechanical support of the failing left ventricle.

Six patients received mechanical support for a failing left ventricle after corrective cardiac operations. Despite intra-aortic balloon pumping and pharmacologic support, intractable failure persisted and cardiopulmonary bypass could not be withdrawn. The left ventricular assist device (LVAD) consists of a nonpulsatile centrifugal pump and two thromboresistant cannulas. Balloon counterpulsation added a pulsatile effect. LVAD support was continued for 72 to 168 hours and five patients were weaned from LVAD support. Two died of persistent low cardiac output within 3 days after pump removal, and a fourth died of multiple organ failure and pneumonia 8 weeks after LVAD removal. Autopsy studies in the first three patients showed myocardial necrosis greater than 50% of the left ventricular mass. Two patients survived after 72 and 74 hours of LVAD support. One patient is fully employed and active 27 months after a cardiac operation; the second is fully active 20 months after operation. Repeat cardiac catheterizations in both have shown all grafts patent and good ventricular function. These two long-term survivors justify the concept of LVAD support and its continued use in selected postoperative patients.