DNA sequences of three beta-1,4-endoglucanase genes from Thermomonospora fusca

The DNA sequences of the Thermomonospora fusca genes encoding cellulases E2 and E5 and the N-terminal end of E4 were determined. Each sequence contains an identical 14-bp inverted repeat upstream of the initiation codon. There were no significant homologies between the coding regions of the three genes. The E2 gene is 73% identical to the celA gene from Microbispora bispora, but this was the only homology found with other cellulase genes. E2 belongs to a family of cellulases that includes celA from M. bispora, cenA from Cellulomonas fimi, casA from an alkalophilic Streptomyces strain, and cellobiohydrolase II from Trichoderma reesei. E4 shows 44% identity to an avocado cellulase, while E5 belongs to the Bacillus cellulase family. There were strong similarities between the amino acid sequences of the E2 and E5 cellulose binding domains, and these regions also showed homology with C. fimi and Pseudomonas fluorescens cellulose binding domains.

Stroke rehabilitation: a model predicting return home

We undertook this study to describe the changes in functional status for patients in a rehabilitation program for acute stroke and to identify the variables that best predict discharge home. Of 282 patients, 75% were discharged home. Increases in functional status were found for all 18 activities of the Functional Independence Measure from admission to discharge. Significant predictors of discharge disposition in a logistic regression model were the admission and discharge functional status scores, length of stay, and living arrangement before the stroke. The functional status at discharge was the most important predictor. Knowledge of these predictors can contribute to more appropriate treatment and discharge planning.

Generation of T cells with lytic specificity for atypical antigens. III. Priming F1 animals with antigen-bearing cells also having reactivity for host alloantigens allows for potent lytic T cell responses

Here, we explore the conditions required for generating two different highly potent F1 antiparental killer cell populations to unusual antigens in rats. The first, L/DA anti-DA, has lytic specificity for two antigen systems: MTA, a mitochondrial antigen expressed on DA and DA Lewis (L) target cells restricted by RT1A class I molecules; and H, an antigen that maps to the class I-like RT1C region and is present only on parental target cells from donors homozygous at the major histocompatibility complex. The second killer population is generated in the reciprocal DA/L anti-DA combination and has lytic specificity only for the H antigen system. We show that the killer cells are T cells, and that generation of these F1 cytotoxic T lymphocytes (CTL) requires an in vivo priming step in which it is essential that the inoculated parental cells bear the relevant target antigens and possess alloreactivity for F1 host antigens. The requirement for alloreactivity and antigen on the same priming cell population suggests that these potent lytic responses depend on a situation akin to a hapten-carrier effect that bypasses otherwise ineffective helper responses by the host to these unusual antigens. Restimulation of F1 lymphocytes in culture is also necessary, requiring the presence of antigen on irradiated lymphoblast stimulator cells, but alloreactivity to responder cell antigens is not necessary; normal, nonactivated lymph node cells are completely ineffective as stimulators. For effective lysis, the target cells need not possess the potential for alloreactivity to responder F1 CTL. We also demonstrate in a preliminary way additional antigen systems defined by killer populations raised with other F1 antiparental strain combinations.

Generation of T cells with lytic specificity for atypical antigens. I. A mitochondrial antigen in the rat

F1 rats primed with normal parental strain lymphocyte populations and restimulated in culture with parental lymphoblasts generate potent cytotoxic T cell responses to unusual antigen systems. Here we describe in the Lewis (L)/DA anti-DA combination an antigen system most likely of mitochondrial origin with the following properties: it is transmitted maternally from DA strain females, inherited in an extra-chromosomal manner, restricted by class I RT1Aa major histocompatibility complex gene products, extinguished on target cells treated with chloramphenicol, and its pattern of expression in different rat strains correlates with restriction fragment-length polymorphisms of mitochondrial DNA. Sequence analysis of the rat ND1 gene indicates that the maternally transferred factor in the rat is not a homologue of the maternally transmitted factor responsible for the mitochondrial antigen in mice. In keeping with its inheritance from DA females, this antigen is present on target cells from (DA female x L male)F1 donors and all other F1 combinations derived from DA female parents, but absent from target cells from some F1 combinations (L/DA and Wistar-Furth [WF]/DA) derived from DA strain males. The presence of this antigen in other F1 combinations (Brown Norway [BN]/DA, August 2880 [AUG]/DA, and PVG/DA) indicates that this mitochondrial antigen system is shared by the DA, BN, and PVG strains, but not by the L and WF strains.

Generation of T cells with lytic specificity for atypical antigens. II. A novel antigen system in the rat dependent on homozygous expression of major histocompatibility complex genes of the class I-like RT1C region

Lymphocytes from parental strain DA rats can induce potent killer cell responses to atypical antigen systems in F1 Lewis (L)/DA and DA/L recipients. Here, we describe an antigen system, H, present on homozygous parental target cells, but not on F1 cells. This antigen system is unusual in several respects: it does not involve class I RT1A gene products usually used by killer cell responses in the rat, it maps to the major histocompatibility complex (MHC) class I-like RT1C region, and it requires homozygous expression of RT1Cav1 alleles. This may be another example, this time involving the RT1C region, of an MHC gene product antigenically altered by an MHC-linked trans-activating modifier gene.

Human immunodeficiency virus infection of human-PBL-SCID mice

Severe combined immunodeficient (SCID) mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID mice) have inducible human immune function and may be useful as a small animal model for acquired immunodeficiency syndrome (AIDS) research. Hu-PBL-SCID mice infected with human immunodeficiency virus-1 (HIV-1) contained virus that was recoverable by culture from the peritoneal cavity, spleen, peripheral blood, and lymph nodes for up to 16 weeks after infection; viral sequences were also detected by in situ hybridization and by amplification with the polymerase chain reaction (PCR). Mice could be infected with multiple strains of HIV-1, including LAV-1/Bru, IIIB, MN, SF2, and SF13. HIV-1 infection affected the concentration of human immunoglobulin and the number of CD4+ T cells in the mice. These results support the use of the hu-PBL-SCID mouse for studies of the pathogenesis and treatment of AIDS.

Effect of tetrahydroaminoacridine on cognition, function and behaviour in Alzheimer's disease

OBJECTIVE

To determine the efficacy of tetrahydroaminoacridine (THA) in Alzheimer's disease.

DESIGN

Randomized, double-blind, multiple crossover trial with three treatment periods, each consisting of 3 weeks of active drug therapy and 3 weeks of placebo administration.

SETTING

Referral-based geriatric practice in a community hospital.

PATIENTS

Thirty-four patients with moderate to severe Alzheimer's disease. Subjects were included if they had stage 3 to 6 disease (as determined by the Reisberg scale) and had not been taking psychotropic drugs for at least 1 month and if informed consent had been obtained from the patients and their next of kin.

INTERVENTIONS

Fifty to 100 mg of THA daily and matched placebo.

RESULTS

Of the initial 34 patients 14 experienced liver toxicity and 3 gastrointestinal side effects during the study; however, all 22 who completed the study were able to tolerate at least the minimum dose. For the 22 patients there was no clinically or statistically significant effect of THA on cognition, functional status or behaviour. The results for individual patients showed no subgroup of THA-responsive patients.

CONCLUSION

THA has no clinically important benefits in Alzheimer's disease and is associated with appreciable toxic effects.

Cytochemical analysis of the notochord in early rhesus monkey embryos

Functional differentiation of the notochord in rhesus monkey embryos at stages 11-12 (25-28 days of gestation) was analyzed by means of ultrastructural cytochemistry. The notochordal cells exhibited well developed Golgi complexes, rough endoplasmic reticulum, mitochondria, and numerous coated vesicles. Large irregular intercellular spaces were common, and some contained fibrils and particulate matter similar to that observed in the perinotochordal space immediately surrounding the notochord. With the glycogen-specific thiocarbohydrazide-silver proteinate technique, solitary particles as well as large aggregates of glycogen were present within the notochordal cells. The center of some aggregates was electron lucent and contained collapsed membranous structures. The results indicate that as early as stage 11 the nonhuman primate notochord exhibits ultrastructural features suggestive of secretory activity and cytological complexity.

Techniques for the determination of left ventricular mass by signal-averaged electrocardiography

The standard ECG correlates poorly with LV mass. The SAECG precisely measures myocardial energy and may allow more exact noninvasive assessment of LV mass. A commercially available system (Corazonix Predictor I) was tested for its ability to reproduce and measure known input energy in square wave and QRS waveforms, using frequency bandwidths different from those used for late potential analysis. A test group of 15 patients was studied to determine optimum filter type and bandwidth for comparison of SAECG energy measurement versus LV mass as determined by echocardiography (Penn conversion) and LV hypertrophy via standard ECG criteria. The best means of energy measurement were maximum and total RMS voltage and the integral of the area under the QRS curve. Optimum correlation with echocardiography was seen with a bidirectional band-pass filter of 5 to 250 Hz applied either to the vector sum of the three orthogonal leads or to the Z lead alone (r values 0.61 to 0.73), which was equal to or superior to standard ECG LV hypertrophy determinants. A second group of 20 patients was studied prospectively to confirm these findings, which yielded similar results.

CONCLUSION

(1) the SAECG when appropriately modified serves as a rapid noninvasive assessment of LV mass. (2) These modifications must examine the entire duration and energy spectrum of the surface ECG and not just the region of late potentials. (3) Very low frequencies (below 5 Hz) must be excluded to eliminate the energy present due to DC offset voltage.

A nonerythroid GATA-binding protein is required for function of the human preproendothelin-1 promoter in endothelial cells

Endothelin-1 (ET-1) is a 21-amino-acid peptide synthesized by endothelial cells that has potent vasoconstrictor activity. Human ET-1 is derived from a 212-amino-acid prepropeptide, termed preproendothelin-1 (PPET-1). To identify cis-acting sequences essential for PPET-1 gene transcription, bovine aortic endothelial (BAE) cells were transfected with plasmids containing 5'-flanking sequences of the human PPET-1 gene fused to the human growth hormone gene as a reporter. Deletional analysis of these fusion plasmids showed that the sequence spanning positions -141 to -127 of the human PPET-1 promoter is required for full transcription activity. Introduction of clustered point mutations into this region of the promoter reduced transcription activity. Gel shift analysis, methylation interference, protein-DNA cross-linking, and oligonucleotide competition studies revealed that BAE cell nuclear extract contains a 47-kilodalton DNA-binding protein recognizing the core motif TATC (GATA) located at positions -135 to -132 of the PPET-1 promoter. The size and specificity of this DNA-binding protein resemble GF-1, a previously described transcription factor of erythroid cells that binds to the same core motif. Gel shift analysis indicated that GF-1 and the DNA-binding protein interacting with the PPET-1 promoter have different tissue distributions; the former is restricted to a subset of hematopoietic cells, and the latter is found in various cell types, including BAE, NIH 3T3, and HeLa cells. By using an antiserum to the C-terminal region of GF-1, the two proteins were also found to be antigenically distinct. When a growth hormone fusion plasmid containing the proximal 141 nucleotides of the PPET-1 promoter was transfected into a variety of cell types, these was preferential expression in cells of endothelial origin. We conclude that a nuclear factor with binding specificity for a GATA motif similar to that of the transcriptional activator GF-1 is necessary for the efficient and cell-specific expression of the human PPET-1 gene.

Cyclosporine-induced autoimmunity in rats carrying thymus allografts

An autoimmune syndrome occurs in cyclosporine-treated, lethally irradiated, and marrow-reconstituted rats after cyclosporine is discontinued. This syndrome, referred to as cyclosporine-induced autoimmunity, requires the presence of a thymus. In this report, we demonstrate that the disease will occur in animals transplanted with thymus tissue from an allogeneic donor, incompatible with the recipient at the major histocompatibility complex. T cells generated from these allogeneic thymic chimeras respond in vitro to thymic donor antigens, suggesting that cyclosporine inhibits self-tolerance induction in the thymus. Because disease is more frequent when the tolerizing antigens expressed in the thymus differ from those expressed in the periphery, the possibility that cyclosporine may mediate its effect via the downregulation of self-antigen presented in the thymus is discussed.

Cloning and sequencing of a Bacteroides ruminicola B(1)4 endoglucanase gene

Bacteroides ruminicola B(1)4, a noncellulolytic rumen bacterium, produces an endoglucanase (carboxymethylcellulase [CMCase]) that is excreted into the culture supernatant. Cultures grown on glucose, fructose, maltose, mannose, and cellobiose had high specific activities of CMCase (greater than 3 mmol of reducing sugar per mg of protein per min), but its synthesis was repressed by sucrose. B. rumincola did not grow on either ball-milled or acid-swollen cellulose even though the CMCase could hydrolyze swollen cellulose. The CMCase gene was cloned into Escherichia coli, and its nucleotide sequence contained a single open reading frame coding for a protein of 40,481 daltons. The enzyme was overproduced in E. coli under the control of the tac promoter and purified to homogeneity. The N-terminal sequence, amino acid composition, and molecular weight of the purified enzyme were similar to the values predicted from the open reading frame of the DNA sequence. However, the CMCase present in B. ruminicola was found to have a monomer molecular weight of 88,000 by Western immunoblotting. This discrepancy appeared to have resulted from our having cloned only part of the CMCase gene into E. coli. The amino acid sequence of the CMCase showed homology to sequences of beta-glucanases from Ruminococcus albus and Clostridium thermocellum.

Echocardiography. Basics for the primary care physician

Echocardiography is commonly performed to assess aortic stenosis, mitral valve prolapse, pericardial effusion and cardiac tamponade, myocardial infarction, endocarditis, and valvular regurgitation. We have found that the more defined and appropriate a request for an echocardiogram is, the better the technician and interpreter can relate observations to the requesting physician. Thus, thorough understanding of the indications and limitations of echocardiography by the primary care physician will result in improved patient care.

Daily intakes of nine nutritional elements: analyzed vs. calculated values

The daily intakes for eight age-sex groups (infants, young children, and male and female teenagers, adults, and older adults) of nine nutritional elements (sodium, potassium, calcium, phosphorus, magnesium, iron, zinc, copper, and manganese) were obtained by laboratory analysis of the Food and Drug Administration's 234 Total Diet Study (TDS) foods and by use of the USDA Nutrient Data Base for Standard Reference. Food substitutions were required for eight TDS foods that had no direct counterparts in the USDA database. When corrections were made for missing values for magnesium, zinc, copper, and manganese in the USDA database, average percent differences between the two methods (USDA-TDS) for the age-sex groups were -2.6 for iron, 0.6 for manganese, 0.9 for zinc, 5 for potassium and phosphorus, 7 for magnesium, 8 for sodium and calcium, and 11.0 for copper. Data in the USDA database (when corrected for missing values) provided estimates of daily intakes of nine nutritional elements that were similar to those obtained by use of data from laboratory analysis in the TDS.

Oligomerization of the bacteriophage lambda S protein in the inner membrane of Escherichia coli

Western blot (immunoblot) analysis of cell extracts from induced bacteriophage lambda lysogens probed with S-protein-specific antibody (raised against an S--beta-galactosidase fusion protein) demonstrated that the bacteriophage lambda S protein begins to appear 10 min after phage induction and is localized to the inner membrane at all times during the lytic cycle. Between 100 and 1,000 molecules of S protein per cell were present at the time of phage-induced lysis. Western blots of chemically cross-linked membranes from induced lysogens showed a ladder of bands at 18, 24, 32, and 42 kilodaltons (the S-protein monomer ran at 8 kilodaltons) that reacted with anti-S-protein antibody. Thus, the S protein appears to reside in the inner membrane as a multimer, and the molecular weights of the cross-linked species are consistent with those of S-protein homopolymers. Sodium dodecyl sulfate-resistant dimers were also detected when S protein was purified by immunoprecipitation.

Fourth branchial pouch sinus: principles of diagnosis and management

The fourth branchial pouch sinus is a congenital anomaly which most frequently manifests itself by recurrent episodes of neck abscess or acute suppurative thyroiditis. This lesion usually becomes symptomatic before the age of 10 years and is more common than has previously been suspected. It has been found on the left side in 93% of the 28 cases reported in the English literature. Barium swallow during periods of quiescence and nasopharyngoscopy have frequently been successful in identifying the presence of these embryological remnants. Definitive therapy consists of total excision of the sinus tract, which can be facilitated by direct endoscopic placement of a Fogarty catheter into the sinus lumen before surgical exploration. The embryological basis for the occurrence of these sinuses is discussed.

Effects of temperature on Escherichia coli overproducing beta-lactamase or human epidermal growth factor

The effects of temperature on strains of Escherichia coli which overproduce and excrete either beta-lactamase or human epidermal growth factor were investigated. E. coli RB791 cells containing plasmid pKN which has the tac promoter upstream of the gene for beta-lactamase were grown and induced with isopropyl-beta-D-thiogalactopyranoside in batch culture at 37, 30, 25, and 20 degrees C. The lower temperature greatly reduced the formation of periplasmic beta-lactamase inclusion bodies, increased significantly the total amount of beta-lactamase activity, and increased the purity of extracellular beta-lactamase from approximately 45 to 90%. Chemostat operation at 37 and 30 degrees C was difficult due to poor cell reproduction and beta-lactamase production. However, at 20 degrees C, continuous production and excretion of beta-lactamase were obtained for greater than 450 h (29 generations). When the same strain carried plasmid pCU encoding human epidermal growth factor, significant cell lysis was observed after induction at 31 and 37 degrees C, whereas little cell lysis was observed at 21 and 25 degrees C. Both total soluble and total human epidermal growth factor increased with decreasing temperature. These results indicate that some of the problems of instability of strains producing high levels of plasmid-encoded proteins can be mitigated by growth at lower temperatures. Further, lower temperatures can increase for at least some secreted proteins both total plasmid-encoded protein formed and the fraction that is soluble.

Exercise-induced alterations of signal-averaged electrocardiograms in marathon runners

Late potentials have been shown to predict malignant ventricular arrhythmias and sudden cardiac death. To determine whether prolonged, strenuous activity is associated with the development of ventricular late potentials, signal-averaged electrocardiography was performed on 30 marathon runners before, immediately after, and during a recovery period at least 1 week after they had a 26.2-mile race. The filtered QRS duration decreased immediately after the marathon to 94.4 +/- 10.0 msec from baseline values of 97.3 +/- 10.1 msec (p less than 0.005). Root mean square energy in the terminal 40 msec of the QRS complex increased immediately after the race from 60.4 +/- 35.6 uV to 71.0 +/- 41.7 uV (P less than 0.5). The duration of signals less than 40 uV in the terminal QRS were not appreciably altered. At the 1-week follow-up study, all parameters closely approximated the baseline values. No runner had a late potential after running the race. The one runner with a late potential at baseline had normal parameters immediately after the race. We conclude that signal-averaged ECG parameters are improved after a marathon is run, and the risk of an arrhythmic sudden death in adult runners without organic heart disease would seem to be low.

Ultrastructural defects in the apical neural folds in mutant embryos with spina bifida

Ultrastructural pathology in the apical neural folds was analyzed by means of tannic acid (TA) and ruthenium red (RR) cytochemistry in abnormal (vl/vl) mutant mouse embryos ranging in age from 17-35 somites. At lumbosacral levels of the spinal cord where closure fails to occur, as well as at more cranial levels where closure occurs but results in dorsal midline abnormalities, normal deposition of TA-positive and RR-positive material occurred in the space that develops between the overlying surface ectoderm (SE) and neuroepithelium (NE). However, in lumbosacral regions, pleomorphic excrescences projected abnormally from the apices of the transitional zone cells between SE and NE cells of the open neural folds. These abnormal projections consisted of enlarged cytoplasmic blebs, as well as entire cells. The cells were not necrotic nor did they show evidence of incipient degeneration. However, it is possible that they represent aberrant putative neural crest cells, as indicated by their location in the transitional zone and by the filopodia and lamellipodia projecting from their luminal surfaces.