Role of coronary artery spasm in progression of organic coronary stenosis and acute myocardial infarction in a swine model. Importance of mode of onset and duration of coronary artery spasm

BACKGROUND

Coronary spasm may play an important role in progression of organic coronary stenosis and myocardial infarction, but the mechanisms responsible for these complications are not known. This study aimed to examine whether the mode of onset and the duration of coronary spasm influenced progression of organic coronary stenosis and acute myocardial infarction in a swine model of coronary spasm.

METHODS AND RESULTS

Göttingen miniature pigs were subjected to cholesterol feeding, balloon-induced coronary arterial denudation, and x-ray irradiation. Five months later, coronary spasm was induced by intracoronary injection of serotonin. In 10 pigs, coronary spasm was provoked abruptly and maintained for 25 minutes by five repeated intracoronary injections of serotonin (10 micrograms/kg) every 5 minutes (group A, abrupt onset and short duration). In group B, coronary spasm was provoked gradually by intracoronary injections of serotonin at graded doses of 0.1, 0.3, and 0.6 microgram/kg every 5 minutes and was then maintained for 25 minutes in four pigs (group B1, gradual onset and short duration) and for 120 minutes in six pigs (group B2, gradual onset and long duration) by repeated intracoronary injections of serotonin (10 micrograms/kg) every 5 minutes. Intramural hemorrhage was noted histologically at the spastic site more frequently in group A with abrupt onset (nine of 10 pigs) than in group B with gradual onset (two of 10 pigs) (p < 0.01). Progression of organic coronary stenosis due to intramural hemorrhage was noted in seven pigs (six pigs in group A and one pig in group B), including three cases of total coronary occlusion. Evidence for the evolution of acute myocardial infarction (serial ECG findings, left ventriculograms, and histological findings) was noted in one pig (7%) of group A or B1 with short duration and in five of six pigs (83%) in group B2 with long duration (p < 0.01 versus group A and B1).

CONCLUSIONS

These results indicate that: 1) intramural hemorrhage was frequently induced by coronary spasm of abrupt but not of gradual onset, 2) intramural hemorrhage resulted in acute progression of coronary stenosis and sometimes resulted in persistent total coronary occlusion leading to acute myocardial infarction, and 3) prolonged coronary spasm resulted in acute myocardial infarction without progression of organic coronary stenosis.

A seal-less centrifugal pump (Baylor Gyro Pump) for application to long-term circulatory support

We are developing a new centrifugal pump, the Baylor Gyro Centrifugal Pump (Gyro Pump), which can function for more than 2 weeks. The concept of the Gyro Pump is that a one-piece rotor-impeller with embedded permanent magnets, driven directly by a brushless direct current motor stator placed outside, rotates like a "gyroscope," and the rotor-impeller is supported by one pivot bearing at the bottom in accordance with the gyroscopic principle. This concept enables us to eliminate a driving shaft and a seal between the driving shaft and the blood chamber, which results in extending the life of the centrifugal pump. The blood passes through the space between the motor stator and the rotor to the impeller portion. In this preliminary phase, two pivot bearings were applied to support the rotor-impeller at the top and the bottom inside the blood chamber. Both pivot bearings showed less blood trauma and less thrombogenicity in in vitro and in vivo studies. The Gyro Pump is a promising second-generation centrifugal pump for long-term circulatory support in the near future.

Versatile one-piece total artificial heart for bridge to transplantation or permanent heart replacement

A versatile, one-piece total artificial heart (TAH) system that can be driven by either an electromechanical acutator (EM-TAH) or a pneumatic source (P-TAH) has been developed. The common units for both TAHs are the conically shaped left and right pusher-plate-type pumps (63 ml SV) that sandwich a thin centerpiece (18 mm) having a respective actuator. The EM actuator, mounted in the middle of the centerpiece, consists of a direct-current brushless motor and a roller screw while the pneumatic actuator consists of a low-pressure air source. The outer diameter of the pumping unit is 97 mm with its central thickness being 82 mm; overall volume is 510 cc. The TAH is operated in the left master alternative ejection mode with the left pump fill signal. High-flex-life Hexsyn rubber is used as the diaphragm, and the blood-contacting surface is coated with dry gelatin. The TAH can provide 3-8 L/min flow with a preload of 1-10 mm Hg against 100 mm Hg afterload. Anatomical fit of the pumping unit has been demonstrated in the pericardial space of 26 heart transplant recipients with average body weight of 78 kg. To date, 2 P-TAH and 4 EM-TAH (1 week) implantations were performed in 80-100 kg calves demonstrating excellent anatomical fit, controllability, and biocompatibility. This versatile TAH is suitable for a bridge to transplantation or permanent heart replacement.

Baylor multipurpose circulatory support system for short- to long-term use

A multipurpose circulatory support system has been developed as both a temporary and permanent device in total artificial hearts (TAHs) and ventricular assist devices (VADs). The multipurpose concept was derived from the development of a totally implantable electromechanical, one-piece TAH. The blood pump is pneumatically driven in short-term use and is electromechanically driven in long-term or permanent use. Both TAH and VAD versions consist of the same components, except for the actuation mechanism. The common components are a compact pumping chamber with the same configuration, a blood contacting surface biolized with gelatin, a pusher-plate, a Hexsyn rubber diaphragm (University of Akron, Akron, OH) and bovine pericardial valves. Both TAHs and VADs have 63 ml of stroke volume, and the VADs are compact compared with other available investigational device exemption devices. Currently, 1 week survival has been achieved using the electromechanical TAH and 2 week survival using the electromechanimcal VAD without anticoagulation. Results suggest that the currently developed system could be applied in varied patients as a temporary device after cardiotomy, a long-term device for bridge to transplantation, or a permanent device for end-stage heart disease.

Infiltration of helper/inducer T lymphocytes heralds central nervous system damage in human T-cell leukemia virus infection

Cellular infiltrates in new and old lesions in two cases of human T-cell leukemia virus associated myelopathy (HAM) were analyzed with anti-CD3 antibody and OPD4 antibody recognizing CD4 + CD45RO + T lymphocytes. A subset of CD4 lymphocytes with helper/inducer function and labeled with OPD4 constitutes up to 65% of CD3 cells in new lesions in the pons and the cervical cord. In contrast, nonhelper cells and macrophages were dominant in long-standing spinal cord lesions of these HAM cases and inflammatory lesions in two cases of Japanese encephalitis. Thus, unlike in viral infections, the central nervous system (CNS) tissue damage associated with human T-cell leukemia virus (HTLV-1) infection appeared to be heralded by the infiltration of helper/inducer T cells.

Sensitivity of the polymerase chain reaction for detecting human T-cell leukemia virus type I sequences in paraffin-embedded tissue. Effect of unbuffered formalin fixation

Recently, the application of the polymerase chain reaction (PCR) to formalin-fixed paraffin-embedded tissue has been reported. But formalin, especially unbuffered formalin, is known to break DNA into small fragments. DNA extracted from MT-2 cells fixed in unbuffered formalin for various periods of time were subjected to the PCR and the effect of unbuffered formalin fixation on the ability of the PCR to detect exogenous sequences; i.e., human T-cell leukemia virus type I (HTLV-I) proviral DNA, was examined. The sensitivity of the PCR decreased as a function of both the duration of fixation and the length of the expected DNA products. When the expected length of the PCR product was about 200 bp, a slight decrease in the sensitivity was observed after 4-day fixation. When it was about 300 bp, a similar decrease was observed following 4-h fixation. In the case of a 500 bp product, the sensitivity began to decrease after 30-min fixation and a 100-fold decrease was observed after 10-day fixation. A decrease was not observed, however, with a 100 bp product. The appropriate design of primers, especially with regard to the length of the amplified product, is essential to keep the sensitivity of the PCR, particularly when the target tissues have been fixed in unbuffered formalin.

Gelatin particle agglutination test for early serodiagnosis of Japanese spotted fever

A gelatin particle agglutination (PA) test for Japanese spotted fever has been developed. Gelatin particles were sensitized with a sonicated causative rickettsia and used as antigens. The antibodies by PA test were detected as early as days 4-7 after the onset, whereas those by indirect immunoperoxidase (IP) test were detected after days 8-11. In addition, PA titers were higher than IP titers before days 20-23. The agglutinins detected by PA test were proven to be IgM because they were all sensitive to dithiothreitol. PA test was, however, less specific than IP test, giving a little nonspecific reaction to the sera from patients with scrub typhus and from individuals unrelated to those two rickettsioses. Nevertheless, PA test, which is simple, rapid, and easy to interpret the results, is useful for the early serodiagnosis of Japanese spotted fever.

Search for human T-cell leukemia virus type I (HTLV-I) proviral sequences by polymerase chain reaction in the central nervous system tissue of HTLV-I-associated myelopathy

Using the polymerase chain reaction (PCR), proviral DNA sequences of the pol and env regions of human T-cell leukemia virus type I (HTLV-I) were directly amplified in paraffin-embedded and frozen tissue sections of active inflammatory central nervous system (CNS) lesions in three autopsy cases of HTLV-I-associated myelopathy (HAM) with serological confirmation. In parallel, the enumeration of UCHL-1 (monoclonal antibody reactive to T-cells) positive cells in the tissue sections subjected to PCR were carried out. Although the control DNA sequence of parathyroid hormone-like peptide gene was definitely amplified, no signals for HTLV-I proviral sequences were detected in these specimens. The number of UCHL-1 positive cell nuclei was almost on the border line of our PCR sensitivity in formalin-fixed tissue, which was estimated to be 20-200 copies. Therefore, it is unlikely that the central nervous system tissue damage in HAM/TSP is a consequence of productive infection of HTLV-I in the CNS tissue.

Effects of endothelin-1 on epicardial coronary tone, coronary blood flow, ECG-ST change and regional wall motion in anesthetized dogs

The effects of intracoronary-administrated endothelin-1 on coronary hemodynamics and regional myocardial function were studied in anesthetized open-chest dogs. Epicardial coronary diameter (CoD) and coronary blood flow (CBF) were measured by a sonomicrometer of 10 MHz piezoelectric crystals and an electro-magnetic flow probe on the left circumflex coronary artery (LCX). Regional wall motion was sonomicrometrically measured at regions supplied by the LCX and left anterior descending artery (LAD) and electrocardiograms were recorded. Endothelin-1, administered as a bolus injections into the LCX via an intracoronary cannula, in a dose-dependent manner reduced COD and CBF. The extent of the reduction of COD and CBF at a dose-dependent manner reduced COD and CBF. The extent of the reduction of COD and CBF at a dose of 300 pmol was 12.3 +/- 1.5% (P less than 0.01) and 86 +/- 5% (P less than 0.01), respectively, of the control. The extent of CBF reduction and deterioration of systolic wall motion were linearly related with the dosage of endothelin-1. ST-elevation (lead II) and fatal ECG abnormalities, including complete atrioventricular block or ventricular fibrillation, were observed with doses above 60 and 100 pmol, respectively. Coronary angiography revealed that filling defects of dye were propagated from the third or distal branches to those of more proximal arteries when the doses of endothelin-1 were cumulatively infused into the LCX. Accordingly, lethal myocardial ischemia induced by endothelin-1 is produced by critical obstruction of rather small coronary vessels.

An indirect microhemagglutination test for Lyme disease

We have developed an indirect microhemagglutination test (IMHA) for detecting antibodies to Borrelia burgdorferi using formalin-fixed chicken erythrocytes sensitized with a sonicated extract of the bacteria. The specificity of IMHA for Lyme disease was compared with that of a conventional indirect immunoperoxidase technique (IP) using sera from the patients with syphilis, randomly-chosen outpatients unrelated to Lyme disease, and from normal individuals. The IMHA was more specific than IP, giving little cross-reaction with syphilis. The IMHA also gave little background reactions with the sera of individuals unrelated to Lyme disease or syphilis. Therefore, the IMHA could be a useful test for the serodiagnosis of Lyme disease.

Mutagenicity of (p-nitrophenyl)adenines in Salmonella typhimurium

Adenine derivatives having a p-nitrophenyl group at position 2, 8, or 9 were directly mutagenic towards Salmonella typhimurium strains TA98 and TA100, whereas N6-(p-nitrophenyl)adenine was not mutagenic. 2,9- And 8,9-bis-(p-nitrophenyl)adenines were also mutagenic, but N6,9-bis-(p-nitrophenyl)adenine was not. The study on 13 (p-nitrophenyl)adenine derivatives for their Salmonella mutagenicity indicates that only those having a p-nitrophenyl ring directly linked to the purine ring are mutagenic, implying the importance of the coplanar character of the nitrophenyl and the purine rings. The nitro group seems essential for the mutagenicity, as shown from the results of assays using nitroarene-sensitive and -insensitive Salmonella strains. The mutagenic potency of this class of compounds is high, comparable to that of 2-nitrofluorene.

Clinical manifestations of tularemia in Japan--analysis of 1,355 cases observed between 1924 and 1987

A total of 1,355 cases of tularemia observed between 1924 and 1987 in Japan were viewed on the basis of clinical manifestations and the results were compared with those in the United States. The incubation period varied from one day to over one month. In 75.5% of cases, the symptoms of illness appeared within seven days with the peak on the third day. A sudden onset of flu-like symptoms was generally observed, and 92% of cases was followed by regional lymph node swelling which mostly appeared in axillary and cubital regions. They were observed predominantly at the left rather than the right side. In contrast with the cases in the United States, the number of cases of ulceroglandular type in Japan was only one third of those of glandular type. None of the pleuropulmonary cases or fatal tularemia have been reported in Japan. The number of oropharyngeal cases has remarkably increased after World War II, and is still on the rise, presumably because of the change of dietary habits in Japan. All these characteristics of Japanese tularemia are assumed to be caused by low virulence of Japanese strains of Francisella tularensis.

Microagglutination test for early and specific serodiagnosis of tularemia

A microagglutination test with safranin-stained Francisella tularensis antigen was compared with a conventional tube agglutination test for the serodiagnosis of tularemia. The microagglutination test was performed in round-bottom microtiter plates by using 0.025 ml of the antisera and of the antigen. The antibody titers obtained by using the microagglutination test were 8 to 64 times higher than those seen with the tube agglutination. By the microagglutination test, the serum agglutinins were detected 3 days earlier in rabbits and 9 days earlier in humans than by the tube agglutination test. The microagglutination test also detected residual circulating antibodies in humans more than 20 years after recovery from infection. These early agglutinins were shown to be in the immunoglobulin M class because of their sensitivities to 2-mercaptoethanol. No significant group agglutination reaction with Brucella abortus was observed. These observations indicate that the microagglutination test is a useful tool for the early and specific serodiagnosis of tularemia.

Targeting of adoptively transferred experimental allergic encephalitis lesion at the sites of wallerian degeneration

To clarify the implication of the major histocompatibility complex class II (Ia) antigen induction in microglia following Wallerian degeneration in the central nervous system (CNS), experimental allergic encephalitis (EAE) was adoptively transferred to Lewis rats in which Ia antigens had been induced in microglia at the sites of Wallerian degeneration. In addition to randomly distributed typical EAE lesions, the recipient rats developed distinct inflammatory lesions in accord with the distribution of Ia-positive microglia; i.e., in the ipsilateral thalamus after cortical cryoinjury, and in the ipsilateral optic nerve, the contralateral optic tract and superior colliculus after unilateral eye ball enucleation. Thus, the EAE locus may be targeted by this approach. The inflammatory response was inducible by transfer of myelin basic protein-stimulated lymphocytes but not by transfer of phytohemagglutinin-stimulated or non-stimulated lymphocytes. When examined using monoclonal antibody surface markers; OX-6 for Ia antigen, W3/13 for pan T lymphocyte and OX-8 for cytotoxic/suppresser T lymphocyte, the types of lymphocytes in these lesions did not differ from those in ordinary EAE lesions in the spinal cord. The potential role of non-immunologically induced Ia-positive cell clusters that serve as a target for autoimmune CNS diseases was discussed.

Cytotropism of Theiler's murine encephalomyelitis viruses in oligodendrocyte-enriched cultures

The cytotropism of two strains, GDVII and DA, of Theiler's murine encephalomyelitis viruses (TMEV) was studied in the oligodendrocyte-enriched murine neural cell cultures. Both GDVII and DA caused cytopathic effects in the neural cell cultures, and double immunostaining for galactocerebroside (Gal-Cer), a marker molecule for oligodendrocyte, and viral antigens disclosed a dual expression of Gal-Cer and viral antigens in over 80% of cells in both cultures 24 h after infection with either GDVII or DA. The kinetics of cell-free and cell-associated infectivity were not significantly different between two cultures. These in vitro observations suggest that neither replication in oligodendrocyte nor cell-associated infectivity is a sole factor in discriminating those two subgroups of TMEV with regard to the demyelinating activity, and that virus cell binding may play an important role in virus persistence and TMEV-induced demyelination.

Intraneuronal laminin-like immunoreactivity in the human central nervous system

Because laminin possesses potent neurotrophic activity, laminin-like immunoreactivity was investigated in formalin-fixed human brains, using affinity-purified anti-human placental laminin rabbit serum. Distinct laminin-like immunoreactivity was observed in neuronal soma of certain nuclear groups, and a 180-kDa band was noted in an immunoblot study of the supernatant of brain homogenate. These observations imply that many but not all central neurons have laminin-like immunoreactive molecules. Their functional role, however, remains to be clarified.

2-(p-Nitrophenyl)-2'-deoxyadenosine, a new type of mutagenic nucleoside

A crude preparation of 2-phenyladenosine was found to be mutagenic in the Ames Salmonella assay. In the purification of this preparation, it was revealed that 2-phenyladenosine itself was nonmutagenic but that 2-(m- and p-nitrophenyl)-adenosines (5m,p) contaminating the sample were the mutagenic principles. A structure-activity relationship study was carried out, and it was found that 5p, 2-(p-nitrophenyl)-adenine (7p), and 2-(p-nitrophenyl)-2'-deoxyadenosine (15p) were strongly mutagenic toward S. typhimurium TA98 and TA100 without metabolic activation, the potency being in the order 15p greater than 7p greater than 5p. The potency of 15p in TA98 was one order of magnitude greater than that of 4-nitroquinoline N-oxide. 15p also showed mutagenicity in the mouse cell line FM3A in culture.

Infectious cDNA clones of the DA strain of Theiler's murine encephalomyelitis virus

The DA strain and other members of the TO subgroup of Theiler's murine encephalomyelitis viruses cause a persistent demyelinating infection, whereas the GDVII strain and other GDVII subgroup strains cause an acute lethal polioencephalomyelitis. We generated an infectious DA cDNA clone inserted into a transcription vector. Virus derived from transfection of transcripts produced a demyelinating disease indistinguishable from that of wild-type virus. The infectious clone provides a critical reagent for the production of interstrain recombinant viruses to help identify genetic loci responsible for the biological activities of the strains.

Mongolian spots associated with cleft lip

Of the present series comprising 66 newborns with cleft lip, 13 (20%) had pigmented macules in the labial skin on the lateral side of the cleft. Histological examination using serial sections were performed on 47 cases and showed evidence of dermal melanocytosis in 40 cases (85%) consisting of 33 (70%) without clinically detectable macules and 7 (15%) with obvious pigmented macules. The fusiform cells in the dermis were positive for dopa reaction and anti-melanocyte antibody. The high incidence of dermal melanocytosis is comparable to that of common Mongolian spots in Asian babies.

Serial assessment of myocardial infarction by using gated MR imaging and Gd-DTPA

In order to assess the usefulness of Gd-DTPA in the evaluation of myocardial infarction, 17 patients were examined with gated MR imaging. Scans were made by using a spin-echo pulse sequence before and after IV administration of 0.15 mmol/kg of Gd-DTPA. The images were made at four intervals (average of 5, 12, 30, and 90 days) after the onset of the infarction. Gd-DTPA uptake at the infarcted area was graded as marked, moderate, or no increase in signal intensity by visual inspection. At these four time intervals, an area of increased signal intensity in the infarcted myocardium was detected on T1-weighted images after administration of Gd-DTPA in 14 (82%) of 17 cases, 16 (94%) of 17 cases, six (38%) of 16 cases, and three (21%) of 14 cases, respectively. Markedly increased signal intensity in infarcted areas was shown on T1-weighted images with Gd-DTPA at 5 and 12 days. The ratio of gadolinium uptake in the infarcted area to that in normal myocardium also was evaluated. At 5 and 12 days, the mean increase in signal intensity in the infarcted area was significantly higher than that in a normal area, but not at 30 and 90 days. Increased signal intensity also was apparent on T2-weighted images without Gd-DTPA at 5 and 12 days; however, the use of late echo reduced the signal-to-noise ratio, leading to image degradation. Uptake of Gd-DTPA was a positive marker in acute myocardial infarction, but no significant uptake of Gd-DTPA occurred in chronic myocardial infarction.

Neurotoxic activity in HTLV-I carrier lymphocyte culture

A close association between human T-lymphotropic virus type I (HTLV-I) infection and a group of chronic myelopathies of unknown etiology has recently been established and the name "HTLV-I associated myelopathy" (HAM) has been coined. Although the mechanism of neural tissue damage in HAM remains virtually unknown, several lines of evidence suggest the involvement of a soluble factor(s) including cytokines and viral proteins in the disease process. In this study, we examined cytopathic effects of the supernatants from 6 HTLV-I carrier human T lymphocyte cell lines on 4 human and one murine neuroblastoma cell lines, and 2 human glioma cell lines. Among 6 lymphocyte cell culture supernatants, only 1 from MT-2 cell culture repeatedly exerted cytopathic effects on human neuroblastoma cells, particularly on IMR-32 cells: marked retraction of neurites leading to cellular clumping. This activity was neither abolished by treatment of the medium at 80 degrees C for 30 min or by UV-irradiation, nor was it neutralized by anti-HTLV-I antibodies. The MT-2 supernatant also induced mild cytopathic changes in 2 other human neuroblastoma cell lines and 2 human glioma cell lines. This activity was abolished by treatment of the medium at 80 degrees C for 30 min but not at 56 degrees C for 30 min. Myelinated murine cerebellum explants and other cell lines showed no morphological changes when incubated with the MT-2 supernatant. In addition, the growth of THP-1 cells, a monocyte/macrophage lineage cell line, was remarkably suppressed when maintained in the MT-2 conditioned medium, accompanied by enhancement of phagocytic activity. The THP-1 conditioned medium, on the other hand, suppressed tumor necrosis factor (TNF) activity detected in the MT-2 culture. These observations suggest that HTLV-I induced cytokines may directly act on neural cells, but their action appears to be regulated by the intricate interactions of lymphocytic and monocytic cells.

Defective immune response to Epstein-Barr virus in patients with acute lymphocytic leukemia

Thirteen children with acute lymphocytic leukemia (ALL) receiving maintenance chemotherapy were tested for anti-Epstein-Barr virus (EBV) antibodies, EBV specific cytotoxic T lymphocyte (EBV-CTL) activity and spontaneous cytotoxicity against Raji cells in order to define the defective cellular immunity in ALL children during complete remission. Among 10 seropositive patients, anti-virus capsid antigen (VCA) antibody titer varied from 1:20 to 1:320 and anti-EBV nuclear antigen (EBNA) antibody was not detectable in four. No patients were positive for anti-early antigen (EA) antibody. EBV-CTL activity and interleukin 2 (IL-2) or interferon alpha (IFN-alpha) augmented EBV-CTL activity in eight seropositive patients was significantly lower than that in the seropositive age matched control group. IFN-alpha, OK-432 or IL-2 augmented spontaneous cytotoxicity were also significantly lower in the patients compared to those in the control group. These defective killer cell activities may allow EBV-infections to enter a severe, fulminant or persistently active state in the patients with ALL receiving aggressive maintenance chemotherapy.