Reactivation of a major histocompatibility complex class II gene in mouse plasmacytoma cells and mouse T cells

Terminally differentiated plasma cells and mouse T cells do not express major histocompatibility complex (MHC) class II genes although class II gene expression is observed in pre-B and mature B cells as well as in activated human T cells. Transient heterokaryons were prepared and analyzed to investigate the mechanisms of inactivation of MHC class II gene in mouse plasmacytoma cells and mouse T cells. The endogenous MHC class II genes in both mouse plasmacytoma cells and mouse T cells can be reactivated by factors present in B cells. This reactivation of class II gene is also observed by fusion with a human T cell line which expresses MHC class II genes, but not with a class II negative human T cell line. It appears that the loss of MHC class II gene expression during the terminal differentiation of B cells or T cell lineage is due to absence of positive regulatory factor(s) necessary for class II transcription.

Primary structure of an inactive mutant of phospholipase A2 in the venom of Bungarus fasciatus (banded krait)

From the acidic components of Bungarus fasciatus venom, a very small amount (0.16%) of a novel phospholipase A2 was obtained. Both neurotoxicity and enzyme activity were found to be lacking. Amino acid sequence study showed that it has a normal backbone of group I snake venom phospholipase A2 with 118 amino acid residues. The lack of enzyme activity was attributed to its mutation of the indispensable Asp residue to an Ala residue, i.e., the usual His-Asp47 turned out to be His-Ala47. This is the eighth isoform of phospholipase A2 found from the venom of Bungarus fasciatus. Examination of structural homology with three other isoforms revealed 66% similarity at most.

Takayasu's arteritis with aortoaortic bypass graft and renal autotransplantation: report of one case

Takayasu's arteritis is a rare inflammatory disease of the aorta and its major branches which occurs predominantly in young women. The clinical course has been described as two stages: 1) initial phase, with inflammatory process and systemic manifestations; and later 2) pulseless phase, with multiple arterial occlusions. A 20-year-old female came to visit this hospital for the first time at 10 years of age with occlusion of the left subclavian artery and of the thoracoabdominal aorta. Aortoaortic bypass surgery was performed using a 14 mm woven graft from the ascending aorta to the descending aorta on the infrarenal portion. The postoperative course was uneventful. Exertional dyspnea and hypertension progressively developed. However, in the past year, angiograms have shown a marked stenosis on the proximal portion of the left renal artery. Autotransplantation for the left-sided kidney was performed. The patient did well, and remained free of symptoms until this time of writing, 12 months after the operation.

Functional roles assigned to the periplasmic, linker, and receiver domains of the Agrobacterium tumefaciens VirA protein

VirA and VirG activate the Agrobacterium tumefaciens vir regulon in response to phenolic compounds, monosaccharides, and acidity released from plant wound sites. VirA contains an amino-terminal periplasmic domain and three cytoplasmic domains: a linker, a protein kinase, and a phosphoryl receiver. We constructed internal deletions of virA that truncate one or more domains and tested the ability of the resulting proteins to mediate environmentally responsive vir gene activation in vivo. The periplasmic domain is required for sensing of monosaccharides (in agreement with earlier results), while the linker domain is required for sensing of phenolic compounds and acidity. The phosphoryl receiver domain of VirA plays an inhibitory role in signal transduction that may be modulated by phosphorylation. The carboxy terminus of the protein was also dispensable for tumorigenesis, while the periplasmic domain was required.

Imaging of multiple coronary artery fistulas to right ventricle by transthoracic and transesophageal echocardiography

A 20-year-old woman presented with extremely rare multiple coronary artery fistulas with left circumflex and right coronary arteries as the feeding vessels and two distinct sites of drainage into the posterior wall of the right ventricle near the apex in close proximity. The large left fistula was well depicted by transthoracic echocardiography, whereas the transesophageal approach better delineated part of the smaller right fistula.

Renal cortical and renal medullary necrosis in the first 3 months of life

Renal cortical necrosis, renal medullary necrosis, and combined renal cortical-medullary necrosis result from renal ischemia without vascular occlusion. Renal hypoperfusion and ischemic injury in infants have been ascribed to massive blood loss, hemolytic disease, septicemia, and severe hypoxemia. In a postmortem study we identified 82 cases among 1,638 autopsies during the 20 years between 1970 and 1989 in infants 3 months old or less at the time of death. The frequency of renal necrosis in autopsy cases increased significantly during the last 6 years of the study. The distribution of the renal lesion was cortical in 28, medullary in 23, and combined in 31. Forty infants carried diagnoses of congenital heart disease, 17 of asphyxial shock, 9 of sepsis, 3 of infectious myocarditis, 9 of major malformations, 4 of anemic shock, 1 of vascular malformation, and 1 of gastroenteritis and dehydration. A significantly higher proportion of babies with congenital heart disease had cortical involvement. Comparison of clinical characteristics revealed a significantly higher frequency of prematurity, respiratory distress syndrome, bleeding diathesis, and possibly sepsis in the children with congenital heart disease, suggesting that these factors are important in the pathogenesis of the renal lesion. Fourteen infants underwent cardiac catheterization; there was no demonstrable association between the renal lesions and the use of radiographic contrast medium. We conclude that severe congenital heart disease itself is a risk factor for life-threatening renal cortical and medullary necrosis.

A simultaneous bilateral attack of infectious corneal ulcers in an extended-wear soft contact lens wearer: a case report

A case study was made of a 23-year-old female with simultaneous bilateral infectious corneal ulcers related to extended-wear soft contact lenses. Cultures revealed Pseudomonas aeruginosa and Acinetobacter calcoaceticus. Multiple high risk factors were combined, including extended-wear, poor lens care, bilateral alternate wearing, and smoking. Amphetamine addiction may also have played a role. After treatment, a visual acuity of 20/20 was achieved in both eyes by the use of rigid gas-permeable contact lenses.

Formycin triphosphate as a probe for the ATP binding site involved in the activation of guanylate cyclase

Formycin A triphosphate (FTP), a fluorescent analog of ATP, slightly increased basal guanylate cyclase activity, but significantly potentiated guanylate cyclase activity stimulated by atrial natriuretic factor (ANF) in rat lung membranes. FTP potentiated ANF-stimulated guanylate cyclase activity with an EC50 at about 90 microM and inhibited ATP-stimulated guanylate cyclase activity with an IC50 at about 100 microM. These results indicate that FTP binds more tightly than ATP for the same binding site. Therefore, FTP would be an excellent tool for studying the ATP binding site.

Rapid dose calculations for stereotactic radiosurgery

A three-dimensional dose calculation algorithm is described for stereotactic radiosurgery using multiple noncoplanar beam arcs. Precalculated dose libraries of 20-deg arc segments, or mini arcs, are stored in computer memory which permits rapid calculation of complete, high resolution, three-dimensional isodose distributions and dose volume histograms. Three-dimensional patient contours and target volumes are obtained from CT scans and angiographic x rays. Rapid dose calculations are made possible by the use of arc libraries and an improved algorithm for mapping beam doses to the dose calculation grid. This permits more flexibility in designing optimum treatment plans, as five-six complete plans can be generated in less than 1 h. Thus many possible treatment options can be tested in the 3-4-h time period typically available in stereotactic procedures between CT scanning and treatment.

Antithrombin III activity in normal and toxemic pregnancies

From August 1989 to October 1990, 83 pregnant Chinese women were the subjects for measuring the levels of plasma functional antithrombin III (AT III) activity. The correlations of AT III activity with perinatal outcome and the changes in maternal hepatorenal function were analyzed. The population was divided into four groups: Group I (n = 30), normal pregnancies; Group II (n = 23), mild pre-eclampsia; Group III (n = 26), severe pre-eclampsia; and Group IV (n = 4), eclampsia. The results demonstrated that: 1) AT III activity decreased with the severity of toxemia (p < 0.001), 2) AT III activity correlated with the degree of perinatal outcome and maternal morbidity, and 3) reduction of AT III activity correlated with impairment of maternal hepatorenal function. In conclusion, plasma AT III activity is a valuable parameter in the evaluation of toxemia.

[A comparison of transrectal fine needle aspiration and biopsy of prostatic lesion]

Transrectal fine needle aspiration and biopsy were performed on 100 patients with suspicious prostatic lesions using 22 gauge aspiration needles and 18 gauge biopsy needles. These collections were made from January 1990 to June 1991. Sufficient prostate tissue for cytological and histological diagnosis were obtained in 97% (97/100) and 99% (99/100), respectively. Thirty-nine patients (39%) were diagnosed having cancer with an accuracy rate of 89.7% (35/39) by histology and 69.2% (27/39) by cytology. One patient with a normal cytological aspiration was found to have an atypical biopsy, therefore, the biopsy was repeated and the prostate showed adenocarcinoma. Our results indicate that the needle aspiration cytology has a less accurate diagnosis rate than the needle biopsy histology. Fine needle aspiration is a safe and effective outpatient procedure but there is a definite learning curve before its use can be fully exploited. It is important to have experienced urologists and pathologists to perform these aspirations until sufficient experience is accumulated.

[Valve replacement for aortic stenosis]

We retrospectively reviewed 122 consecutive patients with aortic stenosis from January 1977 to December 1990. There were 68 male and 54 female patients. Their age ranged from 5 to 73 years old (47 +/- 16, mean +/- SD). Sixty eight patients also had associated mitral valve lesion, 13 patients had tricuspid valve lesion, and 3 patients had coronary artery disease. Aortic valve replacement was performed on all patients. Mechanical valves were implanted in 86 cases and tissue valves in 36 cases. Associated procedures were performed in 54 cases: mitral valve replacement in 34 cases, mitral valve repair in 18 cases and coronary artery bypass grafting in 2 cases. A bicuspid aortic valve was found in 20 cases (16.4%). Hospital mortality was 4.9% (6 cases). Follow-up was completed in 95% of the surviving cases (110 cases). The survival rate was 82 +/- 3% at 13 years and redo-free rate was 73 +/- 8% at 13 years. Seven cases required redo operation, due to tissue valve degeneration in 5 and thrombosis of the mechanical valve in 2. All 7 patients survived. Late death occurred in 6 cases: 3 from malignancy, 2 from stroke and 1 from ventricular arrhythmia. We concluded that valve replacement for aortic stenosis is a safe and satisfactory procedure with good long-term results.

Microheterogeneity of a purified IgG1 due to asymmetric Fab glycosylation

A murine monoclonal anti-granulocyte IgG1, IMMU-MN3, was seen to exhibit heterogeneity. On reduced SDS-PAGE, the purified antibody appeared as two heavy-chain bands of unequal intensity, and only one light-chain band. Hydrophobic interaction chromatography (HIC) also resolved two populations of the IMMU-MN3 antibody. Based on Concanavalin A affinity chromatography, enzymatic digestion with Endoglycosidase F and carbohydrate analysis, it was found that the heterogeneity detected by SDS-PAGE and HIC was due to differences in glycosylation. Furthermore, sequential gel analysis (non-reduced/reduced) demonstrated that the upper heavy-chain band was asymmetrically glycosylated.

Derivation of the SLEDAI. A disease activity index for lupus patients. The Committee on Prognosis Studies in SLE

OBJECTIVE

To standardize outcome measures in systemic lupus erythematosus (SLE). Three indices were identified which could adequately describe outcome (disease activity, damage from disease, and health status); we describe here the development of the Disease Activity Index.

METHODS

Twenty-four variables were identified as important factors in a disease activity index. These were used to generate 574 patient profiles, which were rated on a disease activity scale of 0-10 by 14 rheumatologists. A second rating of 10 of the profiles yielded scores that were not significantly different from the first, indicating that experienced clinicians can reliably make global estimates of disease activity. Multiple regression models were used to estimate the relative importance of the 24 clinical variables in the physicians' global rating of disease activity. These were estimated on a "training set" of 75% of physicians' ratings, and then validated on a "testing set," consisting of the remaining 25% of physicians' ratings.

RESULTS

The explanatory power of the models in the training set was high (R2 = 0.93). The models' regression coefficients for the organ systems were simplified for easier use in clinical practice. This generated a "weighted" index of 9 organ systems for disease activity in SLE, the SLEDAI, as follows: 8 for central nervous system and vascular, 4 for renal and musculoskeletal, 2 for serosal, dermal, immunologic, and 1 for constitutional and hematologic. The maximum theoretical score is 105, but in practice, few patients have scores greater than 45. The SLEDAI predicted well the physicians' ratings in the testing set (Pearson's correlation coefficients = 0.64-0.79).

CONCLUSION

The SLEDAI is a validated model of experienced clinicians' global assessments of disease activity in lupus. It represents the consensus of a group of experts in the field of lupus research.

Studying outcomes and hospital utilization in the elderly. The advantages of a merged data base for Medicare and Veterans Affairs hospitals

That veterans aged 65 years and older are eligible to receive care either in the Veteran Affairs (VA) health care system or in the private sector under Medicare confounds the analysis of veterans' health services utilization and outcomes in two ways. First, changes in eligibility or financial barriers to access with regard to either system influence veterans' decisions about where to seek needed care. Second, analyses of VA care for elderly veterans that rely solely on VA data sources underestimate both overall utilization and treatment complications. Similarly, failure to consider the contribution of health care delivery in the VA system may confound analyses of health care utilization by the Medicare-eligible population. To study the magnitude of such confounding influences, we linked the Medicare and VA health care administrative databases for residents of New England and New York. Results indicated that, for ten surgical procedures commonly performed in the elderly, as well as for hospitalizations resulting from acute myocardial infarction and hip fracture, VA patients receive from 17.6% to 37.4% of hospital care outside the VA system. Private hospitalizations account for 5.5% to 19.5% of the care received by veterans within 6 months after an initial episode of care in a VA hospital. It was also found that initial hospitalizations for study conditions in the VA accounted for 3.6% of all such hospitalizations among elderly Medicare-eligible men. Although overall hospital utilization appears to be underestimated in VA data sources, it was found that ascertaining mortality from sources available within the VA produced excellent results when compared with deaths recorded in the Medicare enrollment files. A national, merged VA-Medicare data base is feasible and would enhance the validity of analyses of health care delivery both for elderly veterans and for the Medicare population.

One-stage operation for treatment after delayed diagnosis of thoracic esophageal perforation

Perforation of the thoracic esophagus can be fatal unless diagnosed promptly and treated effectively. The high mortality with delayed treatment is due principally to an inability to effectively close the perforation and prevent leakage. From 1982 to 1988, 7 consecutive patients (aged 16 to 73 years) were treated after a delayed diagnosis (26 hours to 25 days) of thoracic esophageal perforation. In all patients, the perforation was closed after debridement with total exclusion of the esophagus (T-tube cervical esophagostomy plus absorbable ligatures applied to the esophagogastric junction and the cervical esophagus distal to the esophagostomy). Radical decortication and wide mediastinal and pleural drainage were also done. Nutritional supply was given through a feeding gastrostomy. Antibiotics were administered according to the results of cultures. All patients survived. Continuity of the esophagus was established by removal of the T tube and spontaneous absorption of the ligatures. Endoscopy and esophagography performed 4 weeks after the initial operation showed a well-healed esophagus without stenosis or leakage in all patients. No secondary thoracotomy or esophageal reconstruction was necessary. No dysphagia was noted during follow-up (range, 12 to 50 months; mean follow-up, 23 months). We conclude that primary closure of the perforation and total esophageal exclusion with the use of absorbable ligatures and T-tube esophagostomy can provide a one-stage operation with good results for repair of thoracic esophageal perforation diagnosed late.

Usefulness of predischarge electrophysiologic study in predicting late outcome after surgical ablation of the accessory pathway in the Wolff-Parkinson-White syndrome

A predischarge electrophysiologic study was performed in 113 patients with the Wolff-Parkinson-White (WPW) syndrome who had undergone surgical ablation of the accessory pathway. The study was performed 5 to 20 (mean 10 +/- 3) days after surgery. There were 82 male and 31 female patients (aged 4 to 58 years, mean 36 +/- 13). Sixty-one patients (54%) had manifest, 52 (46%) had concealed and 12 (11%) had multiple accessory pathways. All but 1 patient had atrioventricular reentrant tachycardia incorporating single or multiple accessory pathways during the control electrophysiologic study. The accessory pathways were located in the left ventricular free wall in 60% of cases, right ventricular free wall in 22%, posteroseptum in 13%, and anteroseptum in 5%. The predischarge electrophysiologic study showed that the accessory pathway was capable of anterograde and retrograde conductions in 4 patients (all with manifest WPW syndrome). Four patients showed induction of supraventricular tachycardia, including 2 with atrioventricular reentrant tachycardia, and 2 with atrioventricular nodal reentrant tachycardia. Recurrence of supraventricular tachycardia was noted in 5 patients during a follow-up of 28 +/- 26 months. Of these 5 patients, 2 had inducible and 3 had no inducible supraventricular tachycardia during the predischarge electrophysiologic study.(ABSTRACT TRUNCATED AT 250 WORDS)

The activation of major histocompatibility complex class I genes by interferon regulatory factor-1 (IRF-1)

We have investigated the role of interferon regulatory factor-1 (IRF-1), an interferon-gamma (IFN-gamma) inducible transcriptional activator, on major histocompatibility complex (MHC) class I gene transcription. IRF-1 alone is sufficient to trans-activate both transfected and endogenous class I genes and the effect of IRF-1 appears to be direct and sequence-specific. These data suggest that IRF-1 is involved in the IFN-gamma mediated induction of MHC class I expression.

Dissection of the interferon gamma-MHC class II signal transduction pathway reveals that type I and type II interferon systems share common signalling component(s)

We have used a herpes virus thymidine kinase (HSV-TK) based metabolic selection system to isolate mutants defective in the interferon gamma mediated induction of the MHC class II promoter. All the mutations act in trans and result in no detectable induction of MHC and invariant chain (Ii) gene expression. Scatchard analysis indicates that the mutants have a normal number of surface IFN gamma receptors with the same affinity constant. The mutants fall into two broad categories. One class of mutants is still able to induce MHC class I, IRF-1, 9-27, 1-8 and GBP genes by IFN gamma. A second class of mutants is defective for the IFN gamma induction of all the genes tested; surprisingly, the IFN alpha/beta induction of MHC class I, 9-27, ISG54 and ISG15 genes is also defective in these mutants, although different members of this class can be discriminated by the response of the GBP and IRF-1 genes to type I interferons. These data demonstrate that the signalling pathways of both type I and type II interferon systems share common signal transduction component(s). These mutants will be useful for the study of IFN gamma regulation of class II genes and Ii chain, and to elucidate molecular components of type I and type II interferon signal transduction.

The functions of tryptophan residues in membrane proteins

Membrane proteins have a significantly higher Trp content than do soluble proteins. This is especially true for the M and L subunits of the photosynthetic reaction center from purple bacteria. The Trp residues are not uniformly distributed through the membrane but are concentrated at the periplasmic side of the complex. In addition, Trp residues are not randomly aligned. Within the protein subunits, many form hydrogen bonds with carbonyl oxygens of the main chain, thereby stabilizing the protein. On the surface of the molecule, they are correctly positioned to form hydrogen bonds with the lipid head groups while their hydrophobic rings are immersed in the lipid part of the bilayer. These observations suggest that Trp residues are involved in the translocation of protein through the membrane and that following translocation, Trp residues serve as anchors on the periplasmic side of the membrane.

Tubal embryo transfer for the treatment of infertility

The outcome of treatment for male factor infertility with either gamete intrafallopian transfer (GIFT) or in vitro fertilization and embryo transfer (IVF/ET) has been unsatisfactory. A better approach may be tubal embryo transfer (TET). In our medical center, from November 1989 to December 1990, 80 couples (male factor, n = 35, non-male factor, n = 45) entered our program for TET. Superovulation was conducted with either human menopausal gonadotropins (hMG) or gonadotropin-releasing hormone agonist (GnRH-a, buserelin)/hMG. Ovum retrieval (OR) was possible in 73 patients and successful fertilization after insemination occurred in 64 of them. TET was performed only when there was at least one grade III-V embryo. The mean number of embryos transferred was 3.92 +/- 0.13 (range 1-5). There were 35 pregnancies out of 55 TET (64% per TET, 48% per OR). In the group with male factor infertility, OR occurred in 32, and 24 achieved fertilization. Ten pregnancies were achieved after 19 TET (53% per TET, 31% per OR). In comparison, the group with non-male factor infertility had a higher pregnancy rate (69% per TET and 61% per OR). There have been 15 live births, 14 ongoing pregnancies (eight sets of twins and 21 singletons), five abortions and one ectopic pregnancy. Our results indicate that: 1) TET is a valuable treatment for non-tubal factor infertility; and 2) in the group with male factor infertility, it has the advantages of demonstrating fertilization in vitro and preventing unrewarding laparoscopies.