Nonlinear system identification by m-pulse sequences: application to brainstem auditory evoked responses

The purpose of this paper is to introduce a method for characterizing the nonlinear behavior of the auditory system. The method uses an m-pulse sequence as the stimulus and employs a general nonlinear framework for the auditory system. Like Sutter's binary m-sequence approach, the m-pulse sequence approach is computationally efficient since calculation of the first-order input-output cross-correlation function is all that is necessary for obtaining the nonlinear characteristics of the system. The nonlinear system characteristics are reflected in pulse kernels in contrast to binary kernels associated with the binary m-sequence approach. By assuming the system under study is a third-order nonlinear system, binary and pulse kernels are shown to be related to Volterra kernels. The results suggest that the m-pulse sequence can be used to study the system nonlinear effects of varying the stimulus repetition rate more effectively than conventional methods. Preliminary physiological data obtained by applying m-pulse sequences to the brainstem auditory evoked response (BAER) clearly illustrates the feasibility of obtaining replicable evoked responses using this method.

Negative regulation of the BZLF1 promoter of Epstein-Barr virus

The Epstein-Barr virus BZLF1 gene product (ZEBRA) is a transcriptional activator whose expression in latently infected B cells is sufficient to induce the viral lytic cycle. Since there is no transcription of BZLF1 during latency, we carried out experiments to determine whether cis-acting negative elements in the BZLF1 promoter contribute to the lack of expression during this phase of the virus cycle. A series of deletion plasmids encompassing positions -551 to +14 of the BZLF1 promoter region were constructed and tested for the ability to drive chloramphenicol acetyltransferase (CAT) gene expression in the absence of inducing agents such as 12-O-tetradecanoylphorbol-13-acetate (TPA) and anti-immunoglobulin. Expression from the intact 551-bp region was very weak in most of the cell lines tested, but deletion of 165 bp from the 5' end caused a sevenfold increase in expression of CAT. Within these 165 bp, a minimal 48-bp region was sufficient to down regulate the expression of a simian virus 40/CAT fusion plasmid. The 48-bp negative element consists of 7-bp dyad symmetry elements separated by 27 bp. The rightmost half of the dyad symmetry element partially overlaps a region which has a 14-of-15-bp homology to the human cytoskeletal gamma-actin promoter.

Evaluation of HemoQuant test and enteroclysis in estimating the sites of obscure gastrointestinal bleeding

The HemoQuant test includes the measurement of total fecal hemoglobin (Hb) or porphyrin derived from heme, and of intestinal converted fraction (ICF) which is the performed porphyrin probably by bacteria during enterocolic transit. The mean +/- SD of HemoQuant in 31 healthy subjects was 0.57 +/- 0.49 mg Hb/g stool, values above 2 mg Hb/g stool are considered to be positive. In patients with upper GI bleeding (n = 44), small bowel bleeding (n = 11) and large bowel bleeding (n = 16), the ICF ranged 0.03-23%, 0.09-20.20% and 0.35-11.0%, respectively. There was major overlap in individual ICF due to some influencing factors such as the quantity of fecal blood and the enterocolic transit. We conclude that HemoQuant is a sensitive assay for detection of fecal occult blood, but ICF is not helpful in estimating the anatomic site of bleeding. Seventy-one patients with GI bleeding of obscure origin underwent enteroclysis. The results showed 77.5% had definite lesions in the small bowel, but 22.5% still were undefined. It is suggested that enteroclysis should be performed without delay if upper and lower GI endoscopic studies are negative.

[A study on the male DNA special restricted fragment of bovine]

Bkm, which is related to sexes, is a satellite DNA of the female snake. After the genomic DNA of bovine was digested by Pst I, it was hybridized with Bkm sequence probe (p184) and subcloned in the vector pUC19. Recombinants were identified by the colony in situ and Southern blot hybridization. When we determined genomic DNA of bovine using the male DNA fragment, it was observed that the pattern of hybridization was different because of different sexes. The results showed that we could identify the sex of bovine by Southern blot hybridization with recombinants of male DNA special restricted fragment of bovine origin.

Evidence for reduced fibrinolytic activity in unstable angina at rest. Clinical, biochemical, and angiographic correlates

BACKGROUND

The goal of this study was to evaluate the role of the fibrinolytic system in patients with unstable angina at rest associated with transient electrocardiographic changes.

METHODS AND RESULTS

Tissue plasminogen activator activity in plasma was comparable among patients with unstable angina (n = 17), patients with stable exertional angina (n = 10), and control patients with normal coronary arteriograms (n = 8). In contrast, plasminogen activator inhibitor-1 (PAI-1) activity in plasma was elevated in the unstable angina group (21.67 +/- 9.52 AU/ml) as compared with either the stable angina group (12.01 +/- 7.06 AU/ml, p less than 0.02) or the controls (12.49 +/- 8.54 AU/ml, p less than 0.02). Coronary angiography performed within 24 hours after the last anginal episode showed a similar extent of coronary artery disease in the unstable and stable angina groups. However, intracoronary thrombi were observed in eight patients in the unstable angina group while no thrombus was noted in the stable angina group (chi 2 = 7.22, p less than 0.01).

CONCLUSIONS

We conclude that patients with unstable angina at rest have a reduced fibrinolytic activity and an increased incidence of intracoronary thrombi. It is postulated that elevated PAI-1 activity in the presence of coronary arterial wall injury may be an important factor leading to the development of acute coronary syndromes.

Functional changes of the NADH respiratory chain in rat-liver mitochondria and the content changes of high-energy phosphate groups in rat liver and heart during the early phase of burn injury

Using glutamate plus malate as substrates, the respiratory control ratio of liver mitochondria from burned male Sprague-Dawley rats with full skin thickness burns covering 20 per cent of the body surface area were increased at 45, 60, 75 and 90 min and using alpha-ketoglutarate, were increased at 60 and 75 min after burning, the peak being at 75 min postburn. The ADP/O ratio and the rate of ATP formation were also increased at about 75 min postburn and the ATP content in liver was increased at 120 min following burning. The ATP and creatine phosphate contents in heart tissue were increased at 120 min and at 105, 120 and 135 min postburn respectively. A sham-injured group acted as control. All the results suggested an increased oxidative phosphorylation coupling in some organs during the early phase of burn injury.

Does antiplatelet therapy enhance myocardial salvage after coronary reperfusion?

The aim of this study was to test the hypothesis that either the cyclooxygenase inhibitor aspirin or the thromboxane A2 receptor antagonist sulotroban exerts a direct myocardial effect that enhances myocardial salvage afforded by reperfusion. Accordingly, 21 anesthetized dogs underwent suture occlusion of the left anterior descending coronary artery. At 2.5 h after occlusion, all dogs received intravenous streptokinase (20,000 U/kg body weight over 30 min) and were randomized to the following groups: group I (n = 7) received no additional treatment, group II (n = 7) received aspirin (5 mg/kg intravenously) and group III (n = 7) received sulotroban (10 mg/kg followed by 10 mg/kg per h intravenously). At 3 h after occlusion, the dogs underwent coronary reperfusion for the next 3 h. Myocardial infarct size as a percent of the hypoperfused zone was similar among dogs in group I (42 +/- 8%), group II (41 +/- 10%) and group III (45 +/- 11%). The incidence and the extent of myocardial hemorrhage were similar in all three study groups. Infarct size as a percent of the hypoperfused zone was significantly smaller in dogs without hemorrhage irrespective of treatment (35 +/- 9% versus 63 +/- 5%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[A prevalence survey to gonorrhea in Jilin]

369 suspecious patients with gonorrhea from 6 general hospitals in Jilin between June and December, 1987, were examined clinically and bacteriologically. Gonococcus was found in 332 of 369 cases(90% positive rate) from their externalia excreta by Gram-staining technique. The period prevalence rate of gonorrhea was estimated at 27.8/100,000, ie, 332 from 1,199,445, the average population in Jilin, derived from Jilin Public Security Bureau. The population distribution survey to the patients shows more males than females, more married than unmarried, and more workers, salesmen, drivers and than others. Most of them received a middle-degree education. The cases were found mainly during July, August, and September. The result implies that gonorrhea trends to prevail in Jilin.

[Effects of Ligusticum wallichii on the plasma and CSF levels of dynorphin A1-13 in rabbits under acute experimental cerebral ischemia]

By occluding the bilateral carotid arteries of rabbits to produce bilateral partial cerebral ischemia, and by using radioimmunoassays to measure the levels of dynorphin A1-13 like immunoreactivity (ir-Dyn A1-13) in plasma and cerebrospinal fluid (CSF), the authors find that the levels of ir-Dyn A1-13 in plasma and CSF have significantly increased (P less than 0.01) after cerebral ischemia appears. The result of the Ligusticum wallichii Franch (Ligusticum) pretreatment to the test-group shows a definite improvement of the changes of ir-Dyn A1-13 levels in plasma and CSF. The severity of brain ischemic damage and neurologic dysfunction in Ligusticum-treated animals is lighter than that of saline-treated group, too. In this study, some new approaches are explored to explain the pathophysiology of cerebral ischemia and the mechanisms by which Ligusticum prevents and treats cerebral ischemia.

Pernicious anemia and type A atrophic gastritis in the Chinese

Pernicious anemia has been considered a rare disease among the Chinese. But in recent years, by wide-spread use of gastroscopy, more cases of Type A atrophic gastritis associated with pernicious anemia have been discovered. Among 28 patients with Type A atrophic gastritis, we had identified 20 cases of pernicious anemia, 18 in frank form and 2 in latent form. This paper presented the results of our studies on clinical, endoscopic, and laboratory examinations of these patients. The findings suggest that pernicious anemia was not so rare among the Chinese. If we keep an alertness on this disease, more such cases could be diagnosed.

Myocardial protection with autoperfusion during prolonged coronary artery occlusion

Passive transcatheter coronary arterial perfusion, i.e., autoperfusion, has been introduced for clinical use to ameliorate short episodes of myocardial ischemia during percutaneous transluminal coronary angioplasty. The primary goal of this study was to evaluate the cardioprotective effect of autoperfusion after prolonged coronary artery occlusion. Accordingly, in 24 anesthetized dogs, either the left anterior descending or left circumflex coronary artery was occluded for 6 hours. The dogs were randomized to a control group subjected to coronary artery occlusion alone (n = 13) or to a group treated with transcatheter autoperfusion (n = 11). The hypoperfused zone, i.e., risk area and infarct size, were measured by autoradiography and triphenyltetrazolium chloride staining, respectively. The hypoperfused zone was 30 +/- 2% and 29 +/- 2% in the control and treated (NS) groups, respectively. When infarct size was expressed as a percent of the hypoperfused zone, it was 84 +/- 5% in the control group and 25 +/- 9% in the group treated with transcatheter autoperfusion (p less than 0.001), showing a reduction of 70%. In addition, an in vitro study showed pressure-dependent flow during autoperfusion as reflected by close linear relationship between perfusion pressure and flow (Flow = 0.54 X Pressure + 16.16, r = 0.99, n = 16). These data suggest that although passive coronary arterial perfusion for 6 hours after coronary occlusion does not prevent myocardial necrosis, it markedly reduces myocardial infarction in the canine model.

Subfamily of submaxillary gland-specific Mup genes: chromosomal linkage and sequence comparison with liver-specific Mup genes

Mouse major urinary proteins (MUPs) are encoded by a family of ca. 35 genes that are expressed in a tissue-specific manner in several secretory organs; in the liver, in the submaxillary, sublingual, parotid and lachrymal glands, and in the skin sebaceous glands. In this paper we describe the isolation of a Mup gene, Mup-1.5a, which is expressed predominantly in the submaxillary gland of BALB/c mice. We show that Mup-1.5a is a member of a subfamily consisting of two closely related genes, both of which are closely linked to the Mup-1 locus on mouse chromosome 4. Mup-1 is the locus of a class of Mup genes (Group 1) expressed in the liver. The complete nucleotide sequence of Mup-1.5a has been determined, and was compared to a previously sequenced Group 1 Mup gene. The comparison shows that the differentially expressed Mup genes are uniformly divergent in exons, introns and in their flanking sequences. The regions of homology extend at least 5 kb into the 5' flanking region of Mup genes.

Adeno-associated virus P5 promoter contains an adenovirus E1A-inducible element and a binding site for the major late transcription factor

Activity of the adeno-associated virus P5 transcriptional control region was found to be induced by adenovirus E1A gene products. A pair of adjacent sequence elements was found to mediate both basal and E1A-induced P5 activity. The first element is a binding site for the major late transcription factor (MLTF), a factor first identified on the basis of its binding to a specific sequence within the adenovirus major late promoter. The second element is a tandemly repeated 10-base-pair sequence whose relationship to previously described binding sites is unclear. Each element individually conferred E1A responsiveness on a heterologous promoter, and deletion analysis demonstrated that each contributed to the level of P5 activity in the presence of E1A products both in transfection- and infection-based assays. Although deletion of the MLTF binding site led to reduced P5 transcriptional activity in the presence of E1A proteins, the deletion generated enhanced P5 basal activity in the absence of the transcriptional activator. The negative effect of the MLTF binding site in the absence of activator and its positive effect in the presence of activator combine to enhance the magnitude of the response by the P5 control region to E1A gene products.

Silent genes in the mouse major urinary protein gene family

To date, two classes of mouse major urinary protein (MUP)-encoding genes have been described, the expressed genes and the intervening-sequence-containing pseudogenes. The data presented in this paper define a third class, the silent Mup genes, which are potentially functional but appear not to be expressed under normal circumstances. We describe a MUP subfamily (Mup-1.5) containing two genes, Mup-1.5a and Mup-1.5b, that are nearly identical, differing at only three positions (greater than 99.9% identity) over the entire 4-kilobase (kb) transcription unit and approximately 1 kb of flanking DNA. The similarity between these two genes extends over greater than 35 kb. Using specific oligonucleotides, we have shown that the 5a gene is expressed in BALB/cByJ mice, primarily in the submaxillary gland, whereas the 5b gene is not expressed. However, we found that when a 9.4-kb DNA fragment containing the Mup-1.5b gene was introduced into the mouse germ line, mice in two of the four transgenic lines expressed this gene at a high level and with the tissue-specificity characteristic of the Mup-1.5a gene. These results suggest that the inactivity of the endogenous Mup-1.5b gene is due not to a lack of functional positive regulatory elements, but to long-range, inhibitory position effects.

Campylobacter-like organisms in chronic gastritis, peptic ulcer, and gastric carcinoma

Biopsy samples were taken from the gastric mucosa of 209 patients endoscoped for dyspepsia symptoms. Campylobacter-like organisms (CLOs) were cultured from 74 of 179 (41.4%) cases and seen in sections from 110 of 209 (52.6%) cases and in smears from 119 of 209 (56.9%) cases; totally, 145 of 209 cases were positive, giving a rate of 69.4%. CLOs were positive in 45 of the 57 (78.9%) patients with superficial gastritis, in 52 of the 64 (81.3%) with atrophic gastritis, in 18 of the 21 (85.7%) with gastric ulcer, in 12 of the 14 (85.7%) with duodenal ulcer, and in 8 of the 10 (80.0%) with stump gastritis, whereas only a few CLOs were found in 3 of the 15 (20.0%) histologically normal subjects and in 7 of the 28 (25.0%) patients with gastric carcinoma. The organisms seem to live more frequently in diseased mucosa and are chiefly recognized through their characteristic morphology and habitat. A significant association between the presence of CLOs and chronic gastritis or peptic ulcer disease was noted, and the positive rate and the number of CLOs correlated highly with the activity of chronic gastritis. No such correlation was observed in gastric carcinoma. These findings support the view that CLOs may be etiologically related to chronic gastritis and peptic ulceration, even though their precise role still remains to be determined.

Expression of six mouse major urinary protein genes in the mammary, parotid, sublingual, submaxillary, and lachrymal glands and in the liver

Mouse major urinary proteins (MUPs) are encoded by a family of about 35 to 40 highly conserved genes. In the preceding paper (K. Shahan, M. Gilmartin, and E. Derman, Mol. Cell. Biol. 7:1938-1946, 1987), we presented the sequences of the most abundant MUP mRNAs in the liver (MUP I, II, and III) and in the lachrymal (MUP IV) and submaxillary (MUP V) glands. We have shown that these five mRNAs are coded by five distinct genes, MUP I through V. In the present communication, we examine the expression of MUP genes in all of the six tissues in which MUP mRNAs are synthesized, the mammary, parotid, sublingual, lachrymal, and submaxillary glands and the liver. We show that gene MUP II is expressed in the liver and in the mammary gland, that gene MUP IV is expressed in the lachrymal and parotid glands, and that gene MUP V is expressed in the submaxillary, sublingual, and lachrymal and parotid glands, and that gene MUP V is expressed in the submaxillary, sublingual, and lachrymal glands. Furthermore, we present evidence that in addition to genes MUP I through V, another gene, MUP VI, is expressed in BALB/c mice in the parotid gland. The tissue-specific synthesis of MUP mRNAs is thus brought about by two major mechanisms: the expression, in different tissues, of different members of the family and the expression of a single gene at various levels in different tissues. When a particular MUP gene is expressed in several tissues, transcripts of this gene initiate at the same site and are spliced and polyadenylated in the same manner.

Thermostability of double-stranded deoxyribonucleic acids: effects of covalent additions of a psoralen

We have carried out a thermodynamic study on the effects of covalent additions of the psoralen derivative HMT, 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen, on the stability of double-stranded deoxyoligonucleotides. This was done with two systems. The first was a double-stranded DNA formed by two non-self-complementary oligonucleotides, 5'-GAAGCTACGAGC-3' and 5'-GCTCGTAGCTTC-3', where we site specifically placed an HMT molecule on the thymidine residue in oligonucleotide 5'-GAAGCTACGAGC-3' as either a furan-side monoadduct or a pyrone-side monoadduct. The second was a double-stranded DNA formed by a self-complementary oligonucleotide, 5'-GGGTACCC-3', where we placed an HMT molecule on the thymidine residue of each strand as a furan-side monoadduct or cross-linked the two strands with an HMT molecule linked to the two thymidines. We found that HMT cross-linking of the two strands stabilizes the double helix formed by 5'-GGGTACCC-3', as one might expect. Less predictable results were that the monoaddition of a psoralen stabilizes the double helix formed by the two non-self-complementary oligonucleotides by as much as 1.3 kcal/mol as a furan-side monoadduct and 0.7 kcal/mol as a pyrone-side monoadduct at 25 degrees C in 50 mM NaCl. In contrast, the monoaddition of a psoralen on each of the two thymidines in the double helix formed by 5'-GGGTACCC-3' destabilizes the helix by 1.8 kcal/mol at 25 degrees C in 1 M NaCl. This destabilization arises from an unfavorable enthalpy change (8.6 kcal/mol) and a favorable entropy change (23 cal/K X mol) due to the two HMT molecules at the centers of each strand.(ABSTRACT TRUNCATED AT 250 WORDS)

Needs and implementation of preventive dentistry in China

Based on a literature review and recent surveys, the needs and implementation of preventive dentistry in China have been estimated. The average DMFT of 12- and 15-yr-old schoolchildren in Beijing were 1.61 and 2.11 respectively. The caries prevalence was higher in the coastal cities in the south. The caries rate was also higher in urban areas than in rural areas. There were some controversies in the results of fluoridation studies with one study reporting as high as 47.2% of the children to be afflicted with enamel fluorosis. The community periodontal disease status and treatment needs index (CPTNI) showed that 93% of the 12-yr-olds had bleeding, 98% had calculus and 15% had shallow pockets, with 100% of the children needing prophylaxis. There was a high prevalence of dental malocclusion with 54% of schoolchildren with dental anomalies, of whom 36% needed treatment. Much emphasis had been placed on oral pathology, oral medicine and maxillofacial surgery in the curriculum of Stomatology in Chinese dental schools.