Coronary artery aneurysms: A 25-patient study

Coronary artery aneurysm is a rare disorder, characterized by abnormal dilatation of a localized portion or diffuse segments of the coronary artery. We studied clinical demographics, catheterization findings, and clinical outcomes in an Asian patient cohort with documented coronary artery aneurysms. Compared to a Caucasian adult population, our patient cohort had a lower incidence of coronary artery aneurysm (0.25% vs. 2.6%), and more patients with nonobstructive coronary artery aneurysms (70%); age, gender, and coronary distribution were comparable. The initial presentation of myocardial infarction occurred in five patients (5/17, 30%) with nonobstructive coronary artery aneurysms; however, none who were receiving preventive medications consisting of anticoagulant and antiplatelet agents subsequently developed myocardial infarction. We conclude that the incidence of coronary artery aneurysms with or without associated significant coronary stenosis seems to be lower in the Asian population. In contrast, the incidence of nonobstructive coronary artery aneurysms is considerably high and should not be thought of as a relatively benign disease entity if not treated with preventive medications. Rheumatoid arthritis-related vasculitis might be a cause of coronary artery aneurysm. Surgical intervention is based on the severity of coronary artery stenosis. The result of medical treatment has been compatible with long-term survival. Cathet. Cardiovasc. Intervent. 48:31-38, 1999.

Evaluation of arterial compliance in patients with carotid arterial atherosclerosis

BACKGROUND

High-resolution peripheral vascular sonography has the capability to determine vessel compliance. A number of factors affect compliance in humans, including age, hypertension and atherosclerosis. However, compliance in patients with coronary artery disease (CAD) combined with carotid artery lesions has not been well studied. The objectives of this study were: 1) to determine whether carotid artery compliance is reduced in patients with CAD and carotid artery lesions, and 2) to determine whether decreased arterial compliance is related to an abnormality in vascular wall structure.

METHODS

The study participants included 12 patients with CAD and carotid artery disease (group III), 13 patients with CAD only (group II) and 13 age-matched normal subjects who served as controls (group I). High-resolution peripheral vascular ultrasonography was performed to directly visualize the common carotid artery and to measure its diameter and wall thickness. Carotid artery elastic properties were determined relative to arterial diameter and pressure generated within the heart.

RESULTS

Carotid artery walls were thicker in Group II and III patients than in normal subjects (1.49 +/- 0.03 mm, 1.98 +/- 0.04 mm, vs 1.22 +/- 0.03 mm, p < 0.05 and p < 0.01). There were significant differences in wall thickness between subgroups of CAD patients (p < 0.01). Carotid distensibility was lower (21.8 +/- 1.2 x 10(-6).N-1.m2, 14.8 +/- 1.7 x 10(-6).N-1.m2, vs 25.6 +/- 1.5 x 10(-6).N-1.m2; p < 0.05 and p < 0.01) and Young's modulus of elasticity was higher (3.12 +/- 0.43 x 10(5).Nm-2, 4.18 +/- 0.30 x 10(5).Nm-2, vs 2.34 +/- 0.23 x 10(5).Nm-2; p < 0.05 and p < 0.01) in group II and III patients than in normal subjects. These two indices of carotid artery compliance also differed between subgroups of CAD (p < 0.01). Increased wall thickness may occur secondary to changes in the architectural structure of the vessel wall, and these atherosclerotic changes lead to decreased compliance of arteries.

CONCLUSION

The mechanical properties of the carotid arteries provide reliable information regarding changes caused by atherosclerosis.

Cloning of a galactose-binding lectin from the venom of Trimeresurus stejnegeri

A galactose-binding lectin isolated from the venom of Trimeresurus stejnegeri is a homodimer C-type lectin. The cloned cDNA encoding the monomer of Trimeresurus stejnegeri lectin (TSL) was sequenced and found to contain a 5'-end non-coding region, a sequence which encodes 135 amino acids, including a typical 23 amino acid signal peptide followed by the mature protein sequence, a 3'-end non-coding region, a polyadenylation signal, and a poly(A) region. To completely characterize the deduced amino acid sequence, on-line HPLC-MS and tandem MS were used to analyse the intact monomer and its proteolytic peptides. A modified peptide fragment was also putatively identified by HPLC-MS analysis. The deduced amino acid sequence was found to contain a carbohydrate-recognition domain homologous with those of some known C-type animal lectins. Thus TSL belongs to group VII of the C-type animal lectins as classified by Drickamer [(1993) Prog. Nucleic Acid Res. Mol. Biol. 45, 207-232]. At present, a number of C-type lectins have been purified from snake venom, but most of them have been characterized only at the protein level. To our knowledge, this is the first known cDNA sequence of a true C-type lectin from snake venom.

Comparative study on the distribution of ovalbumin glycoforms by capillary electrophoresis

Two commercial turkey egg ovalbumins (TEOs) with different quantities of mannose, were further purified by reversed-phase high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis for either of the purified glycoproteins showed one big wide band and one close small band. Capillary electrophoresis was used for the investigation of the separation of glycoforms of both glycoproteins. The best resolution of the glycoforms was obtained, reproducibly, with 100 mM borate, 1.8 mM 1,4-diaminobutane and pH 8.6 electrophoretic buffer. At least 13 glycoform peaks could be separated for either of the two glycoproteins. Their glycoform patterns were highly similar except for the conspicuous decrease in quantity of four glycoforms in the ovalbumin containing less mannose, compared to that of the other with more mannose. Coinjection electrophoresis of the two glycoproteins indicated that almost every glycoform peak of the former exactly overlapped with its corresponding glycoform peak of the latter. These results clearly indicated that the two TEOs possessed the same glycoform patterns but differed in quantity at least four glycoforms. It was found that the glycoform patterns were remarkably different between TEO and chicken egg ovalbumin.

Shortened microsatellite d(CA)21 sequence down-regulates promoter activity of matrix metalloproteinase 9 gene

One characteristic elements in the promoter of the matrix metalloproteinase 9 (MMP-9) gene is the d(CA) repeat. To investigate whether this element regulates the transcription of the MMP-9 gene and its enzymatic activities, we sequenced the promoter region isolated from esophageal carcinoma cell lines. TE9 cells with low MMP-9 enzymatic activity had the number of d(CA) repeats shortened from 21 to 14 or 18. TE8, TE10 and TE11 cells with high MMP-9 activities had 21 or 23 d(CA) repeats. Luciferase assays using MMP-9 promoter containing 18, 14 or 0 d(CA) repeats showed transcriptional activities which were 50, 50 or 5%, respectively, of the level achieved with promoter containing 21 d(CA) repeats. Sequence analysis of the promoter of 223 Japanese subjects revealed that most had two alleles with 20, 21 or 22 d(CA) repeats, whereas six had one or two alleles with 14, 18 or 19 d(CA) repeats. We postulate that length alteration of the d(CA) repeat causes phenotypic differences among carcinoma cells and that microsatellite instability may contribute to the polymorphism of d(CA) repeat length.

Synthesis and evaluation of 1,4,5,6-tetrahydropyridazine derivatives as influenza neuraminidase inhibitors

1,4,5,6-Tetrahydropyridazine derivative 15 and its C-5 epimer 19, which possessed side chains similar to GS4071, were synthesized via a hetero Diels-Alder reaction, and evaluated as influenza neuraminidase inhibitors. Compounds 15 and 19 exhibited a microM range of influenza neuraminidase inhibitory activity.

Lignocaine plus morphine in bolus patient-controlled intravenous analgesia lacks post-operative morphine-sparing effect

Lignocaine has been used successfully to treat burn pain and neuropathic pain. We have conducted a randomized, double-blind trial to assess the morphine-sparing effect of intravenous lignocaine in patients with acute pain. After major abdominal surgery, patients were treated with post-operative patient-controlled intravenous analgesia in two groups: group M (n = 25, morphine 0.2 mg mL-1) and group ML (n = 25, morphine 0.2 mg mL-1 plus lignocaine 3.2 mg mL-1). The patient-controlled analgesia system was programmed to deliver a 5 mL bolus with a 50 mL per 4 h limit; the lockout time was 10 min. Both groups closely resembled each other in terms of demographic data, pain intensity, cumulative morphine dose and the morphine-associated nausea, vomiting and pruritus. However, the sedation scores in group ML patients during the first post-operative day were significantly greater than those in group M. The incidence of lignocaine-related lightheadedness and dry mouth was also significantly greater in group ML than in group M. It was concluded that the addition of lignocaine 3.2 mg mL-1 to morphine 0.2 mg mL-1 given via patient-controlled analgesia system does not provide a post-operative morphine-sparing analgesic effect.

Biexponential decomposition of a neuraminidase inhibitor prodrug (GS-4104) in aqueous solution

PURPOSE

To examine the degradation kinetics and identify the degradation products of a neuraminidase inhibitor prodrug. GS-4104.

METHODS

Degradation was studied as a function of pH and temperature using a stability-indicating RP-HPLC assay. Degradation products were isolated by RP-HPLC and identified by NMR. Specific rate constants were calculated based on a scheme defined by products(s) analysis.

RESULTS

Three distinct degradation products were observed in the pH region studied (pH 2-8): isomer I, GS-4071, and isomer II. Isomer I resulted from the N, N-migration of the acetyl group. Gs-4071 was formed by the hydrolysis of the ethyl ester. Both GS-4071 and isomer I degraded further to isomer II by N, N-acyl migration and ester hydrolysis, respectively. The N, N-acyl migration reaction was characterized using two dimensional heteronuclear multiple bond correlation (HMBC) NMR. The decomposition kinetics of GS-4104 follow a biexponential decay at pH 2-7. The degradation kinetics of Gs-4104 at pH 4.0, 70 degree C were independent of the initial GS-4104 concentration.

CONCLUSIONS

The degradation profile indicates that development of solution or solid dosage from of GS-4104 with adequate shelf-life stability at room temperature is feasible.

Full 1H NMR assignment of a 24-nucleotide RNA hairpin: application of the 1H 3D-NOE/2QC experiment

The subject RNA models the binding site for the coat protein of the R17 virus, as well as the ribosome recognition sequence for the R17 replicase gene. With an RNA of this size, overlaps among the sugar protons complicate assignments of the 1H NMR spectrum. The cross peaks that overlap significantly in 2D-NOE spectra can frequently be resolved by introducing a third, in our approach the double-quantum, frequency axis. In particular the planes in a 3D-NOE/2QC spectrum perpendicular to the 2Q axis are extremely useful, showing a highly informative repeating NOE-2Q pattern. In this experiment substantial J-coupling confers special advantages. This always occurs for geminal pairs (H5'/H5" for RNA plus H2'/H2" for DNA), as well as for H5/H6, for H3'/H4' in sugars with substantial populations of the N-pucker, for H1'/H2' for S-puckered sugars, and usually for H2'/H3'. For the 24-mer RNA hairpin the additional information from the 3D-NOE/2QC spectrum allowed assignment of all of the non-exchangeable protons, eliminating the need for stable-isotope labeling.

Temporal and spatial expression of erbB4 in ectodermal and mesenchymal cells during primary palatogenesis in noncleft and cleft strains of mice

Primary palatogenesis in mice is similar to that in humans, and spontaneous cleft lip appears to be multifactorially determined in both. Binding of a ligand to erbB4 has been shown to stimulate the receptor's protein kinase activity, which subsequently stimulates a signal-transduction cascade leading to cell growth and differentiation, and to morphogenesis during development. In this study, an immunohistochemical technique was used to investigate the temporal and spatial expression of erbB4 in the primary palate of cleft (A/WySn) and noncleft strains of mice (BALB/cBy). Positive staining of erbB4 was found in ectodermal and mesenchymal cells of facial prominences before the primary palate formation stage (day 10, hour 20) in both strains. During the primary palate formation stage (day 11, hour 20), positive staining of erbB4 was found in the ectodermal and mesenchymal cells of the facial prominences of the noncleft strain, but not in those of the cleft strain. These results suggest erbB4 expression may be associated with normal primary palatogenesis of mice and, conversely, cleft lip may be associated with a deficiency of erbB4 expression during primary palate formation in mice.

Pathological study of splenomegaly associated with cadmium-induced anemia in rats

Splenomegaly was observed both in male and female Sprague-Dawley rats after 1 week of exposure to CdCl2 (0.6 mg Cd/kg/day). Spleen weight reached about double that in controls by 8 weeks of Cd exposure. Histopathological examination of the enlarged spleen revealed that iron- and lipid-laden histiocytes were clustered in the periarterial lymphatic sheath, and the red pulp appeared to be expanded. It is noteworthy that electron microscopy revealed marked poikilocytosis and Heinz body formation in red blood cells (RBCs) in both the sinus and cord. Histiocytes were swollen by a granular substance in the cytoplasm and also many secondary lysosomes. These morphological findings indicate that degradation of damaged RBCs induced by exposure to Cd might be promoted in the spleen and possibly cause splenomegaly. This RBC damage-hemolysis-splenomegaly sequence is also considered to be associated with the etiology of Cd-induced anemia. In addition to the abnormal RBC degradation, nuclei of lymphocytes in the Cd-exposed spleen exhibited high electron density, consistent with a preapoptotic state suggesting the immunosuppressive effect of Cd.

Growth, respiration and nitrogen content in needles of Scots pine exposed to elevated ozone and carbon dioxide in the field

Single Scots pine (Pinus sylvestris L.) trees, aged 30 years, were grown in open-top chambers and exposed to two atmospheric concentrations of ozone (O3; ambient and elevation) and carbon dioxide (CO2) as single variables or in combination for 3 years (1994-1996). Needle growth, respiration and nitrogen content were measured simultaneously over the period of needle expansion. Compared to ambient treatment (33 nmol mol(-1) O3 and 350 micromol mol(-1) CO2) doubled ambient O3 (69 nmol mol(-1)) significantly reduced the specific growth rates (SGRs) of the needles in the early stage of needle expansion and needle nitrogen concentration (N1) in the late stage, but increased apparent respiration rates (ARRs) in the late stage. Doubled ambient CO2 (about 650 micromol mol(-1)) significantly increased maximum SGR but reduced ARR and N1 in the late stage of needle expansion. The changes in ARR induced by the different treatments may be associated with treatment-induced changes in needle growth, metabolic activities and turnover of nitrogenous compounds. When ARR was partitioned into its two functional components, growth and maintenance respiration, the results showed that neither doubled ambient O3 nor doubled ambient CO2 influenced the growth respiration coefficients (Rg). However, doubled ambient O3 significantly increased the maintenance respiration coefficients (Rm) regardless of the needle development stage, while doubled ambient CO2 significantly reduced Rm only in the late stage of needle expansion. The increase in Rm under doubled ambient O3 conditions appeared to be related to an increase in metabolic activities, whereas the decrease in Rm under doubled ambient CO2 conditions may be attributed to the reduced N1 and turnover rate of nitrogenous compounds per unit. The combination of elevated O3 and CO2 had very similar effects on growth, respiration and N1 to doubled ambient O3 alone, but the interactive mechanism of the two gases is still not clear.

Patient barriers to cancer pain management: from the viewpoint of the cancer patients receiving analgesics in a teaching hospital of Taiwan

BACKGROUND

The purpose of this study was to investigate the barriers to receiving analgesics for cancer pain in Taiwanese patients.

METHODS

The sample consisted of 128 hospitalized patients. All of the subjects were receiving analgesics. Three questionnaires entitled "Barriers Questionnaire-Taiwan Form (BQT)", "Brief Pain Inventory Short Form", and "Pain Management Index (PMI)" were used in this study. Data were analyzed using Student's t-test and Pearson correlation.

RESULTS

The results showed that most of BQT subscales including disease progression, time interval, tolerance, injection, addiction, fatalism and side effects were approaching toward the moderate or high end of the scale. 42.1% (n = 54) of the patients had negative PMI scores indicating that they were using less than adequate analgesics for pain. There was a significant difference between those who had adequate medication and those who did not, in terms of disease progression score and the total BQT score.

CONCLUSIONS

Overall the result revealed that pain management in these cancer patients was inadequate. Misconceptions on the part of patients still exist. Educational intervention could be an effective means for overcoming such barriers in Taiwanese patients who received analgesics for cancer pain.

Congenital sinus of Valsalva aneurysm: a multiplane transesophageal echocardiographic experience

Sinus of Valsalva aneurysm is a rare congenital anomaly which, if overlooked, may be associated with increased mortality and morbidity. Multiplane transesophageal echocardiography proved useful in identifying a variety of associated structural heart disease. This study sought to assess the accuracy of the surgical result on the basis of the multiplane transesophageal echocardiography findings and to describe patient demographics and clinical outcome in an Oriental patient cohort. From July 1984 to December 1995, clinical, catheterization, echocardiographic, and surgical results were retrospectively studied in 23 patients with documented sinus of Valsalva aneurysm. Compared with previous reports of Oriental patients, our patient cohort was older (p < 0.025), had more associated aortic, mitral, and tricuspid regurgitation (p < 0.01), but had fewer coexistent ventricular septal defects (p < 0.01), and had more associated coronary artery disease (9%). Multiplane transesophageal echocardiography precisely showed three undiagnosed and/or ambiguous transthoracic echocardiographic studies, and the preoperative transesophageal echocardiography TEE findings were confirmed intraoperatively in the last eight consecutive patients. We concluded that multiplane transesophageal echocardiography provides conclusive information and is the current technique of choice for diagnosis and clinical management of patients with sinus of Valsalva aneurysm; although the natural history of sinus of Valsalva aneurysm remains uncertain, it is likely that the incidence of unruptured sinus of Valsalva aneurysm is considerably higher in the elderly than has been previously reported.

Solution structure of a duplex DNA with an abasic site in a dA tract

The presence of dA tracts in DNA can lead to stable curvature of the DNA, and this curvature can be important in gene regulation, DNA packaging, and other processes. Since damage to DNA may eliminate this stable curvature, the solution state structure of the duplex of d(CGCAAAAATGCG) paired with d(CGCATTDTTCCG), with D indicating an abasic site, has been determined. The undamaged DNA bends into the major groove both in solution and in the crystal state. The presence of the abasic site in the dA tract region induces changes in the DNA structure up to four base pairs away from the damaged site. The structure of the DNA is dependent on whether the abasic site is in the alpha or beta hemiacetal form. These consequences are quite different from the more localized effects that have been observed for "normal" DNAs containing abasic sites. Thus, there appears to be a strong sequence dependence of the structural effects of abasic sites just as there is for undamaged DNA. Furthermore, these results indicate that the presence of an abasic site can alter DNA bending and hence is likely to have significant long range effects on gene regulation and other properties that are dependent on the stable curvature of DNA.

Histamine 2 receptor blocker-ranitidine and sinus node dysfunction

BACKGROUND

Histamine 2 (H2) receptors were observed to be present in the sinus node. H2 receptor blockers could attenuate the histamine-induced increase in sinus rate and could thereby worsen sinus node dysfunction. However, the data pertaining to electrophysiological effects of H2 receptor blocker ranitidine on sinus node function are not available as yet, although bradycardia has been occasionally reported along with ranitidine. The present study evaluates the electrophysiological effects of ranitidine on sinus node function, and also determines the safety of administering ranitidine to patients suffering from sinus node dysfunction.

METHODS

Thirty-nine patients with clinical diagnosis of sinus node dysfunction were selected for this study. Electrophysiological effects of intravenous injection of 150 mg ranitidine on sinus node function was evaluated. Tests were performed for 21 patients in the basal state (Group 1) and for 18 patients (Group 2) after autonomic blockade (propranolol 0.2 mg/kg, and atropine 0.04 mg/kg). The sinus cycle length (SCL), sinus node recovery time (SNRT), corrected sinus node recovery time (CSNRT), sinoatrial conduction time (SACT), atrio-His (AH) and His-ventricle (HV) intervals and blood pressure (BP) before and after ranitidine were analyzed.

RESULTS

In Group 1, changes in SCL, SNRT, CSNRT, SACT, AH, HV and BP were not found to be significant. However, in Group 2, wherein the patients received ranitidine after autonomic blockade, it was observed that ranitidine significantly prolonged SCL (905.0 +/- 31.0 to 1000.0 +/- 40.0 msec, p = 0.001), decreased systolic BP (134.7 +/- 4.7 to 124.8 +/- 4.8 mmHg, p < 0.001), and diastolic BP (71.9 +/- 2.0 to 67.9 +/- 1.9 mmHg, p = 0.001), while the changes in SNRT, CSNRT, SACT, AH and HV were not significant.

CONCLUSIONS

A clinical dose of 150 mg ranitidine must be administered by a slow intravenous infusion for at least 5 minutes in case of patients suffering from sinus node dysfunction. Continuous monitoring of BP and heart rate are necessary, especially in cases of autonomic denervation.

Measurement of gastrointestinal intramucosal pH is a poor guide to tolerable levels of anemia during isovolemic hemodilution in a canine model of coronary stenosis

OBJECTIVE

To determine the relationship between gastrointestinal intramucosal pH and myocardial oxygenation during isovolemic hemodilution in dogs with critical coronary artery stenoses.

DESIGN

Prospective sequential evaluation of ileal intramucosal pH and regional myocardial function of a critically perfused area of myocardial tissue in a canine model of normovolemic hemodilution.

SETTING

A research laboratory.

SUBJECTS

Fifteen dogs.

INTERVENTIONS

A micrometer snare was placed around a main coronary artery (8 left anterior descending artery, 7 right coronary artery). Three pairs of sonomicrometer crystals were placed in the heart to measure regional myocardial contraction. A gastrointestinal tonometer was placed in the ileum and used to measure luminal PCO2. This PCO2 value was used to calculate the ileal intramucosal pH. The animals underwent normovolemic hemodilution until myocardial ischemia occurred in the region supplied by the snared vessel. Measurements were continued for a further 40 minutes.

MEASUREMENTS AND MAIN RESULTS

Following instrumentation, stabilization, and critical constriction of a coronary vessel, percentage changes in systolic shortening of myocardial tissue in the region of critical perfusion were determined every 20 minutes. Ileal intramucosal pH and commonly measured cardiovascular variables were determined at the same time points. Myocardial ischemia occurred after 80 minutes of hemodilution, when the mean (+/- SD) hemoglobin concentration had fallen from a baseline level of 123 +/- 18 g/L to 82 +/- 14 g/L (P < .01). From the start of hemodilution to 40 minutes after myocardial ischemia occurred, there were no significant changes in heart rate, cardiac output, oxygen consumption, arterial acid-base balance, or arterial PCO2. Oxygen delivery decreased by approximately 45% (5.99 +/- 1.66 to 3.41 +/- 0.90 mL/kg per minute; P < .01) but there were no changes in ileal intramucosal pH (7.31 +/- 0.08 to 7.30 +/- 0.08; P = .90).

CONCLUSIONS

Myocardium compromised by coronary stenosis is more sensitive to normovolemic hemodilution-induced ischemia than the normally perfused gut mucosa. This limits the potential utilization of the measurement of gastrointestinal intramucosal pH as a guide to tolerable levels of anemia in critically ill patients.

Photosynthetic responses of Scots pine to elevated CO(2) and nitrogen supply: results of a branch-in-bag experiment

Naturally seeded Scots pine (Pinus sylvestris L.) trees, age 25-30 years, were subjected to two soil-nitrogen-supply regimes and to elevated atmospheric CO(2) concentrations by the branch-in-bag method from April 15 to September 15 for two or three years. Gas exchange in detached shoots was measured in a diffuse radiation field. Seven parameters associated with photosynthetic performance and two describing stomatal conductance were determined to assess the effects of treatments on photosynthetic components. An elevated concentration of CO(2) did not lead to a significant downward regulation in maximum carboxylation rate (V(cmax)) or maximum electron transport rate (J(max)), but it significantly decreased light-saturated stomatal conductance (g(sat)) and increased minimum stomatal conductance (g(min)). Light-saturated rates of CO(2) assimilation were higher (24-31%) in shoots grown and measured at elevated CO(2) concentration than in shoots grown and measured at ambient CO(2) concentration, regardless of treatment time or nitrogen-supply regime. High soil-nitrogen supply significantly increased photosynthetic capacity, corresponding to significant increases in V(cmax) and J(max). However, the combined elevated CO(2) + high nitrogen-supply treatment did not enhance the photosynthetic response above that observed in the elevated CO(2) treatment alone.

Effects of elevated O3 and CO2 on chlorophyll fluorescence and gas exchange in Scots pine during the third growing season

Naturally regenerated, 30-year-old Scots pines (Pinus Sylvestris L.) were grown in open-top chambers and exposed in situ to doubled ambient O(3), doubled ambient CO(2) and a combination of elevated O(3) and CO(2) from 15 April to 15 September for three growing seasons (1994-1996). To examine the effects of O(3) and/or CO(2) on photosynthesis, chlorophyll a fluorescence and gas exchange were measured simultaneously. Doubled ambient O(3) significantly decreased the rates of photosynthesis at all levels of photon flux density. This was related mainly to a significant decrease in the photochemical efficiency of photosystem II (PS II) and the rate of whole electron transport, rather than to a decrease in stomatal conductance. When measurements were made at doubled ambient concentration of CO(2) (700 micromol mol(-1)), doubled ambient CO(2) treatment did not lead to a significant change in the intrinsic capacity of photosynthesis, as manifested by no changes in PS II, the rate of electron transport, the maximal rate of photosynthesis and the apparent quantum yield of CO(2) assimilation. However, elevated CO(2) increased the sensitivity of stomatal conductance to light and decreased maximal stomatal conductance. When O(3) and CO(2) were combined, the O(3)-induced decrease in photosynthesis rate was reduced significantly by a high concentration of CO(2). This may be partly related to the decrease in stomatal conductance induced by the high concentration of CO(2). The complete mechanism behind this interaction is, however, still unclear.

Photosynthetic responses to needle water potentials in Scots pine after a four-year exposure to elevated CO(2) and temperature

Effects of needle water potential (Psi(l)) on gas exchange of Scots pine (Pinus sylvestris L.) grown for 4 years in open-top chambers with elevated temperature (ET), elevated CO(2) (EC) or a combination of elevated temperature and CO(2) (EC + ET) were examined at a high photon flux density (PPFD), saturated leaf to air water vapor pressure deficit (VPD) and optimal temperature (T). We used the Farquhar model of photosynthesis to estimate the separate effects of Psi(l) and the treatments on maximum carboxylation efficiency (V(c,max)), ribulose-1,5-bisphosphate regeneration capacity (J), rate of respiration in the light (R(d)), intercellular partial pressure of CO(2) (C(i)) and stomatal conductance (G(s)). Depression of CO(2) assimilation rate at low Psi(l) was the result of both stomatal and non-stomatal limitations on photosynthetic processes; however, stomatal limitations dominated during short-term water stress (Psi(l) < -1.2 MPa), whereas non-stomatal limitations dominated during severe water stress. Among the nonstomatal components, the decrease in J contributed more to the decline in photosynthesis than the decrease in V(c,max). Long-term elevation of CO(2) and temperature led to differences in the maximum values of the parameters, the threshold values of Psi(l) and the sensitivity of the parameters to decreasing Psi(l). The CO(2) treatment decreased the maximum values of V(c,max), J and R(d) but significantly increased the sensitivity of V(c,max), J and R(d) to decreasing Psi(l) (P < 0.05). The effects of the ET and EC + ET treatments on V(c,max), J and R(d) were opposite to the effects of the EC treatment on these parameters. The values of G(s), which were measured simultaneously with maximum net rate of assimilation (A(max)), declined in a curvilinear fashion as Psi(l) decreased. Both the EC + ET and ET treatments significantly decreased the sensitivity of G(s) to decreasing Psi(l). We conclude that, in the future, acclimation to increased atmospheric CO(2) and temperature could increase the tolerance of Scots pine to water stress.

Determination of the number and location of the manganese binding sites of DNA quadruplexes in solution by EPR and NMR in the presence and absence of thrombin

The interaction of a DNA quadruplex with thrombin has been studied by first determining the sites of manganese binding to the quadruplex in the absence of thrombin. This has been followed by determining if the interactions with thrombin displace the bound manganese. A different DNA quadruplex has also been studied as a control. The refined solution structures of two DNA quadruplexes have been used to predict the electrostatic potentials of these DNAs. The calculated electrostatic potentials have been used to predict the locations of the binding sites of the paramagnetic ion manganese to these DNAs. The enhanced relaxation of DNA protons due to the binding of the paramagnetic metal ion Mn2+ has been used to experimentally determine the locations of the binding sites. The NMR results and the predictions based on the electrostatic potentials both place the binding sites of the manganese in the narrow grooves of these quadruplex DNAs. The predicted locations are spatially close to those experimentally observed, and the predicted and experimental locations also have similar electrostatic potential energy. These results have allowed a validation of the predictions of electrostatic potentials from structure. The 15mer quadruplex has two strong Mn2+ binding sites with one in each narrow groove. Both Mn2+ are released when the 15mer is complexed with thrombin, indicating that both narrow grooves are involved in the 15mer-thrombin interactions. The dimer quadruplex has a different structural motif than the 15mer and the presence of thrombin does not appreciably affect its interactions with Mn2+.

Evidence of genetic heterogeneity of hypertrophic cardiomyopathy in eight Chinese patients

BACKGROUND

The genetic basis causing hypertrophic cardiomyopathy (HCM) was found due to missense mutations in cardiac beta-myosin heavy chain (beta-MHC), cardiac troponin T and alpha-tropomyosin genes in certain affected families. However, most mutations and majority of the affected families were reported to be related to beta-MHC gene. Till now, 20 different missense mutations of beta-MHC gene identified in more than 40 independent families were distributed in exons 8, 9, 13, 14, 15, 16, 19, 20, 21 and 23. Therefore, we chose these 10 exons for screening.

METHODS

Eight probands with HCM and 1 normal control were included for screening. 32P-labeled PCR products of these 10 exons of beta-MHC gene were amplified from genomic DNA obtained from peripheral lymphocytes. PCR-DNA single strand conformation polymorphism (PCR-SSCP) analysis was performed using electrophoresis with polyacrylamide gels with and without 10% glycerol. Large amount copies of these 10 exons were also made from genomic DNA with PCR. Detection of sequencing variation of these exons was determined by the direct sequencing method with dideoxy chain termination method and 35S.

RESULTS

No abnormal extra bands were noted on PCR-SSCP analysis. Sequencing analysis showed no missense mutation in these probands.

CONCLUSIONS

Genetic heterogeneity of HCM is evident in Chinese patients with HCM.

Protein crystal growth in microgravity using a liquid/liquid diffusion method

Crystallization of proteins by liquid liquid diffusion method was performed in microgravity using the MDA Minilab aboard the US Space Shuttle. Three proteins, namely lysozyme, trichosanthin, and a new lechin, were crystallized in the space experiment. In contrast to the results of space experiments with a tube-like vapor diffusion method, the crystallization conditions for growing better crystals in space are remarkably different from the conditions optimized on earth. This may be due to difficulties in ground optimization, which are caused by gravity-dependent phenomena, in particular the specific convective flow occurring with liquid liquid diffusion.

Left atrial appendage flow velocity and spontaneous echo contrast in patients with rheumatic mitral stenosis: a multiplane transesophageal echocardiographic study

BACKGROUND

Left atrial spontaneous echo contrast (LASEC), a putative marker of thrombo-embolic risk, is commonly located in the left atrial appendage (LAA). The aims of this work were to evaluate, using multiplane transesophageal echography, the echocardiographic determinants, specifically LAA outflow Doppler velocity, in the presence of SEC in patients with rheumatic MS.

METHODS

Transthoracic and transesophageal echocardiographic tests were performed on 61 patients. The patients were divided into 3 groups based on the presence and type of valvular disease. Patients in group I (n = 28) presented with rheumatic mitral stenosis (MS). Patients in group II (n = 18) presented with valvular heart disease other than MS, and patients in group III (n = 15) had no history of valvular heart disease. The left atrium and appendage were examined for the presence of spontaneous echocontrast and thrombus, using multiplane echo scopy with transducer rotation. Minimal and maximal appendage areas were measured, on a computer-assisted bablet, by tracing a line from the top of the limbus of the left upper pulmonary vein to the appendage endocardial border. The LAA ejection fraction was calculated according to the formula: (maximal area-minimal area)/maximal area. Mitral valvular condition was evaluated with transthoracic and transesophageal echocardiography. Left atrial appendage blood flow velocity profiles were obtained with pulsed-wave Doppler at the orifice of the LAA.

RESULTS

LASEC was present in 18 of 28 patients with mitral stenosis (64.3%). Patients with LASEC showed a greater incidence of atrial fibrillation (14/18 vs 12/43, p < 0.005), larger LAD (53.67 +/- 8.74 vs 40.54 +/- 14.85, p < 0.005), smaller LAAEF (38.7 +/- 1.53 vs 69.5 +/- 24.0, p < 0.05), smaller LAAMEV (20.28 +/- 10.07 vs 2.95 +/- 25.11, p < 0.005) and smaller LAAMFV (24.6 +/- 12.23 vs 36.00 +/- 11.01, p < 0.01), when compared with patients without LASEC. For group I, LAAEF, LAAMEV and LAAFV were smaller in patients with SEC than in patients without SEC (p < 0.005, p < 0.05, p < 0.01). However LAD values were similar for patients with and without SEC (53.67 +/- 8.75 vs 54.20 +/- 18.81, p = NS). Both LAAMEV and LAAMFV were related to SEC in patients with atrial fibrillation. However, LAD did not show the same trend.

CONCLUSIONS

LASEC is more commonly observed in patients with rheumatic mitral stenosis or atrial fibrillation. Both LAAMEV and LAAMFV are associated with SEC in these patients.

Measurements of heart rate variability in patients with unexplained syncope

BACKGROUND

Syncope is a common clinical issue with complex and heterogenous etiologies. Research has shown a large proportion of syncope remained unexplained, even after serial investigations. Head-up tilt test with or without isoproterenol infusion could elicit a recurrence in most patients with unexplained syncope. Therefore, autonomically neural-mediated bradycardia and hypotension have been cited as the mainstays of the mechanism. Since the autonomic function can be reflected by heart rate rariability, this study proposed to determine 24-hour heart rate variability in patients with unexplained syncope.

METHODS

Fifteen patients, 14 males and 1 female, who were defined as showing symptoms of unexplained syncope, were the subjects of this study. Their ages ranged from 38 years to 79 years. Seventeen healthy volunteers matching in age and sex served as the control group. For each patient and volunteer, 24-hour ambulatory electrocardiographic monitoring was done. Heart rate variability was defined as SDNN index, SDNN, SDANN, rMSSD, and pNN50 in time domain measures; and low, high, and total frequency in frequency domain measures.

RESULTS

There was a significantly lower value at low frequency, high frequency, total frequency, rMSSD, and pNN50 in the syncope group than in the control group (p < 0.05). There was no significant difference in SDNN, SDNN index, SDANN and LF/HF ratio between these two groups.

CONCLUSIONS

Patients with unexplained syncope had autonomic withdrawal; this was the case either in both sympathetic and parasympathetic components without changing the sympatho-vagal balance, or in purely parasympathetic component.

Deficient and delayed primary palatal fusion and mesenchymal bridge formation in cleft lip-liable strains of mice

During mammalian primary palate formation, the facial prominences enlarge around the nasal pit, fuse and then merge to give rise to the tissue of the upper lip and premaxillary region. The mechanisms involved in successful primary palate formation and how they are affected in the cleft lip genotype remain poorly understood. The purpose of this study was to compare morphometrically internal development and growth of the primary palate in five different strains of mice. Two of the strains, BALB/cByJ, and C57BL/6J, have normal primary palate development, and three of the strains, A/J, A/WySn, and CL/Fr, have stable frequencies of cleft lip associated with genotype. In the present study, frequencies of 4, 23, and 24%, respectively, were observed on day 13. For palatal growth analysis, embryos were collected on days 10 and 11, staged by number of tail somites (TS), and the heads were photographed and serially sectioned for measurement of primary palate components. The heights of the epithelial seam and the mesenchyme bridge between the facial prominences were measured on serial sections and areas of contact were calculated. The position or depth of the maxillary prominence was determined from the number of frontal sections from its tip to the rostral end of the nasal fin. Analysis of measurements showed that in cleft lip strains enlargement of the epithelial seam and replacement of epithelia by a mesenchymal bridge were both delayed relative to somite stages. Measurements from day 11 embryos with complete failure of contact were excluded from the growth analyses. The mesenchymal bridge formed at 12--13 TS in noncleft strains, 14 TS in the A/J strains with higher cleft lip frequency, and 15--17 TS in A/WySn and CL/Fr strains with higher cleft lip frequency. Forward growth of the maxillary prominence was highly correlated with the primary palate measurements and mesenchymal bridge formation in all strains. In both cleft and noncleft strains, the primitive choanae open at 18--20 TS and the medial nasal region narrows with advancing embryonic development. As a result, cleft lip-liable strains have a narrower window in development in which a robust mesenchymal bridge must form, thus increasing the liability to cleft lip.

Determination of the number and location of the manganese binding sites of DNA quadruplexes in solution by EPR and NMR

The paramagnetic metal ion Mn2+ has been used to probe the electrostatic potentials of a DNA quadruplex that has two quartets with an overall fold of the chair type. A quadruplex with a basket type structure has also been examined. The binding of the paramagnetic ion manganese to these quadruplex DNAs has been investigated by solution state electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies. The EPR results indicate that the DNA aptamer, d(GGTTGGTGTGGTTGG), binds two manganese ions and that the binding constants for each of these sites is approximately 10(5) M-1. The NMR results indicate that the binding sites of the manganese are in the narrow grooves of this quadruplex DNA. The binding sites of the DNA quadruplex formed by dimers of d(GGGGTTTTGGGG) which forms a basket structure are also in the narrow groove. These results indicate that the close approach of phosphates in the narrow minor grooves of the quadruplex structures provide strong binding sites for the manganese ions and that EPR and NMR monitoring of manganese binding can be used to distinguish between the different types of quadruplex structures.

Distribution of p21ras during primary palate formation of non-cleft and cleft strains of mice

Cleft lip, with or without cleft palate, is one of the most common defects in craniofacial formation. The primary palatogenesis of mice is similar to that of humans and spontaneous cleft lip is associated with genotype in both mice and humans. To investigate the temporal and spatial expression of ras genes in cleft (A/WySn) and non-cleft strains of mice (BALB/cBy), a broad spectrum ras antibody was used. Positive staining was found in ectodermal, mesenchymal, and neuroepithelial cells of facial prominences before the primary palate formation stage (10 d 20 hr) in both strains. During the primary palate formation stage (11 d 20 hr), positive staining was found in the ectodermal and mesenchymal cells of the facial prominences of the non-cleft strain but not in those of the cleft strain. These results suggest ras genes may play a role in the primary palatogenesis of mice. Cleft lip could be associated with the deficiency of ras gene expression during primary palate formation of mice.

Anesthesia for elective cardioversion: a comparison of thiopentone and propofol

BACKGROUND

Cardioversion is still a trend of therapy for cardiac dysrhythmias. With the application of new intravenous anesthetics, cardioversion can be performed safely and effectively with rapid onset of and quicker recovery from anesthesia. We compared the anesthetic effects of a new synthetic agent, propofol, with thiopentone which was mostly used in the past.

METHODS

Twenty four ASA class II to III adult patients scheduled for elective cardioversion in the coronary care unit were included in this study. All patients were given fentanyl (2 micrograms/kg, i.v.) three min before induction and were randomly assigned to receive either thiopentone 1.5 mg/kg (group 1) or propofol 1 mg/kg (group 2) for induction of anesthesia. Supplementary oxygenation was administered throughout.

RESULTS

Both drugs could provide satisfactory anesthesia for elective cardioversion without major complications. Recovery time was shorter with propofol (p < 0.05). Comparing with previous reports, a higher incidence of apnea and prolonged sedation were noted in this study. This might be due to the additive effect of thiopentone or propofol with fentanyl.

CONCLUSIONS

Both anesthetics were suitable for elective cardioversion with negligible side effects in hemodynamically stable patients.

Use of transesophageal echocardiography for evaluation of resectability of lung cancer

BACKGROUND

When patients with lung cancer are to undergo surgical resection, chest x-ray and computed tomography (CT) are widely used for evaluation of staging and of the resectability of the lesion. Unfortunately, the above methods cannot always provide sufficient information about resectability and some patients undergo unnecessary operations. Transesophageal echocardiography (TEE) has opened a new window for viewing cardiac structure and function. By TEE, one can also image the surrounding tissues and great vessels under continuous monitoring.

MATERIALS AND METHODS

We pre-operatively applied the awake TEE method in twenty whose chest CT showed suspected invasion of the heart by the tumor.

RESULTS

Our experience showed the following: (1) TEE can clearly identify whether lung cancer has invaded the heart and/or great vessels and therefore avoiding unnecessary operation; (2) Two patients had tumor seen abutting epicardium and/or aorta without invasion (under continuous imaging). Two patients had tumor compressing the right and left atrium with intact but not invading pericardium, and underwent successful surgical resection.

CONCLUSION

We concluded that it is useful to apply TEE preoperatively in evaluating the resectability of the lung cancer especially when a chest CT shows suspicion of local invasion of the heart and great vessels; thus unnecessary thoracotomy can be avoided.

Tertiary structure motif of Oxytricha telomere DNA

The tertiary structure of a single-stranded DNA containing the sequence of Oxytricha telomere DNA has been determined. This DNA adopts a compact tertiary structure that consists of four base-paired tetrads of guanine residues which are connected by three loops. The tetrads show significant deviations from planarity, and two of the loops exhibit significant loop-loop interactions. The structure of this telomere contains syn-thymine residues, which are in the loops, as well as an intraloop pyrimidine-pyrimidine base pair between residues that are separated by a single residue. The tertiary structure of the telomere DNA is consistent with prior results that showed that two thymines distant in sequence could be photo-cross-linked. The overall folding pattern of this telomere DNA is similar to that previously determined for a DNA aptamer, which binds to and inhibits thrombin, though the details of the two structures are quite distinct.

Comparison of the effects of nifedipine and nitroglycerin on coronary blood flow using intracoronary Doppler catheter

Different effects of nifedipine and nitroglycerin on large coronary arteries measured by the Xenon washout method are well documented in early reports, but results of direct measurements of the flow velocity of the large vessels were inconsistent. The goal of this investigation was to compare the effects of nifedipine and nitroglycerin on coronary blood flow using an intracoronary Doppler catheter. Fourteen patients with normal coronary arteries (group 1) and eight (group 2) with coronary artery diseases (more than 75% concentric stenosis over the left anterior descending artery in the middle portion) were presented on diagnostic procedure for evaluation of chest pain or abnormal exercise tests after written informed consents. We compared the effects of nitroglycerin (0.6 mg) and nifedipine (10 mg) given sublingually on coronary blood flow velocity using a Doppler coronary catheter. The results indicated that the maximal increase in large coronary arterial diameter induced by nifedipine was similar to that induced by nitroglycerin. Nifedipine increased diastolic and systolic velocity area indices (DVAI and SVAI), and reduced diastolic and systolic coronary vascular resistance (DCVRI and SCVRI). In contrast, nitroglycerin reduced DVAI and SVAI and minimally increased DCVRI and decreased SCVRI in group 2 patients. The increased heart rate and decreased blood pressure induced by both drugs were similar. The differences in the rate-pressure product between the two drugs were not significant. Nifedipine increased flow velocity and decreased coronary vascular resistance, but nitroglycerin achieved the opposite effect, especially in patients with coronary artery disease.

The tertiary structure of a DNA aptamer which binds to and inhibits thrombin determines activity

The solution-state three-dimensional structure of the DNA aptamer d(G1G2T3T4G5G6T7G8T9G10G11T12T13G14G15) which binds to and inhibits thrombin has recently been determined by NMR methods (Wang et al., 1993). This DNA adopts a highly compact, highly symmetrical structure which consists of two tetrads of guanosine base pairs and three loops. The basic features of this three-dimensional structure are preserved when the aptamer binds to thrombin. The three-dimensional structure can be used as a basis for interpreting the relative activities of modified aptamers as well as for proposing a model for the aptamer-thrombin complex. This investigation also provides a demonstration of a novel approach to medicinal chemistry in which a wide range of molecules are synthesized, a lead molecule is identified, and the structural information on the lead compound allows for rational design of additional compounds of potential therapeutic value.

A morphometric analysis of cell densities in facial prominences of the rhesus monkey embryo during primary palate formation

The mechanisms by which the craniofacial complex undergoes morphogenetic change during primary palate formation remain unknown. Although changes in cell dispersion and extracellular matrix content are known to be involved in growth of embryonic primordia, little information about these parameters is available for the mammalian face. The purpose of this study was to analyze cell densities in different facial regions of rhesus embryos during primary palate formation. Eight serially-sectioned embryos of stages 13 to 18 in the collection at the California Primary Research Center, most labeled with 3H-thymidine, were analyzed by making regional cell counts at x400 with an ocular micrometer. Three embryos with autoradiographic label preserved in every section were used to analyze patterns of labeling through the depth of the entire face. The results showed that different regions of an embryonic face have significantly different cell densities. At the early stages, the cell densities were high in the maxillary prominences, and the lateral and medial nasal prominences; whereas cell densities were low in midline tissues. At later stages, cell densities were lower in the lateral portion of the maxillary prominences than in the nasal prominences. Serial counts through the face showed regional variation in individual prominences, but central high-density cores did not appear to be present. Labeling with 3H-thymidine was present in all facial primordia. Labeling indices were consistently higher in facial prominences than in midline tissues ventral to the brain. The results suggest that regional changes in cell densities could be used to reflect net changes in cell dispersion associated with altered balances between cell proliferation and extracellular matrix content in embryonic facial primordia.

Detection of abnormal esophageal motility and gastroesophageal reflux in patients with angina-like chest pain by a radionuclide esophageal transit test

A modified radionuclide esophageal transit test including the esophageal mean transit time (MTT), residual fraction (RF) and retrograde index (RI), was carried out to evaluate esophageal motility and to detect gastroesophageal reflux in three groups: (A) 25 patients (13 males, 12 females, age: 45-65 years) with angina-like chest pain but normal coronary angiogram; (B) 31 patients (14 males, 17 females, age: 42-63 years) with coronary artery disease (CAD) demonstrated by abnormal coronary angiographic findings and intractable angina-like chest pain even after treatment; and (C) 25 normal volunteers (10 males, 15 females, age: 39-67 years). In groups A and B abnormal results were found in 60% (15/25) and 39% (12/31) for MTT; in 28% (7/25) and 39% (12/31) for RF and in 36% (9/25) and 58% (18/31) for RI (i.e., higher than the mean +/- 2 SD of normal values; MTT: 5.72 +/- SD 0.91, RF: 0.129 +/- SD 0.057, RI: 0.055 +/- SD 0.054), respectively. We conclude that the causes of non-cardiac chest pain in group A patients with normal coronary arteries were primarily esophageal dysmotility or spasm (prolonged MTT). However, in group B patients decreased pressure of the lower esophageal sphincter due to the side effects of anti-angina drugs induced delayed cleaning of the esophagus (higher RF) or gastroesophageal reflux (higher RI).

A DNA aptamer which binds to and inhibits thrombin exhibits a new structural motif for DNA

The investigation of the three-dimensional structure of the DNA aptamer d(G1G2T3-T4G5G6T7G8T9G10G11T12T13G14G15) which binds to and inhibits thrombin has been carried out by NMR methods. This DNA exhibits a number of long-range NOEs between residues which are not adjacent in sequence, which allowed the determination of the novel tertiary structure adopted. This DNA adopts a highly compact, highly symmetrical structure which consists of two tetrads of guanosine base pairs and three loops. The residues of the tetrads alternate anti-syn-anti-syn. This novel structural motif for DNA may also be relevant to the structure of telomere DNA.

The use of transesophageal echocardiography to evaluate the effectiveness of patent ductus arteriosus ligation

The ligation of patent ductus arteriosus (PDA) is a comparatively easy operation, but some complications are possible. The most common complication is incomplete ligation of the PDA; others include inadvertent ligation of the descending aorta or left pulmonary artery, transient rise in systemic blood pressure and increased left ventricular afterload, and acute right heart failure due to pulmonary hypertension. The completeness of the PDA ligation is usually determined only by the operating physician's experience, including the use of an esophageal stethoscope or a finger on the lesion to feel for vibration. These methods sometimes fail to detect an incomplete ligation. With transesophageal echocardiography (TEE), we have monitored the entire course of the PDA ligation directly without interrupting the surgical procedure, and precisely determined the completeness of the ligation. We also expect that TEE will enable us to avoid other complications as well.

[Facilitatory effect of Pinellia ternata lectin on quantal release of acetylcholine from nerve terminals]

Pinellia ternata lectin (PTL) extracted from the rhizome of Pinellia ternata Briet by porcine thyroglobulin-Sepharose 4B column exhibits hemagglutination activity and carbohydrate binding specificity for mannan. Here we reported the effects of PTL on the resting membrane potential of muscle fiber and on the release of acetylcholine (ACh) from the motor nerve terminals in the phrenic nerve diaphragm preparations of mice. The results showed that PTL increased the frequency of miniature end-plate potential (MEPP). In 30 min after the treatment of the preparation with lectin 100 micrograms.ml-1, the frequency of MEPP reached 20 times higher than that of the control. Addition of mannan 1 mg.ml-1 restored the raised discharge of MEPP to its control level immediately. Similar to the effect of PTL on MEPP frequency, the amplitude and mean quantal content of end-plate potential also increased after PTL. At 100 micrograms.ml-1, the lectin depolarized the muscle membrane slightly, while at 10 micrograms.ml-1 no effect on the membrane potential was found. These results were interpreted as the intracellular Ca2+ elevation due to a permeability increase of the nerve terminal to ions after PTL.

Recent advances in primary palate and midface morphogenesis research

During the sixth week of human development, the primary palate develops as facial prominences enlarge around the nasal pits to form the premaxillary region. Growth of craniofacial components changes facial morphology and affects the extent of contact between the facial prominences. Our recent studies have focused on developing methods to analyze growth of the primary palate and the craniofacial complex to define morphological phases of normal development and to determine alterations leading to cleft lip malformation. Analysis of human embryos in the Carnegie Embryology Collection and mouse embryos of cleft lip and noncleft strains showed that human and mouse embryos have similar phases of primary palate development: first, an epithelial seam, the nasal fin, forms; then a mesenchymal bridge develops through the nasal fin and enlarges rapidly. A robust mesenchymal bridge must form between the facial prominences before advancing midfacial growth patterns tend to separate the facial components as the medial nasal region narrows and elongates, the nasal pits narrow, and the primary choanae (posterior nares) open posterior to the primary palate. In mouse strains with cleft lip gene, maxillary growth, nasal fin formation, and mesenchymal replacement of the nasal fin were all delayed compared with noncleft strains of mice. Successful primary palate formation involves a sequence of local cellular events that are closely timed with spatial changes associated with craniofacial growth that must occur within a critical developmental period.

Pericardiocentesis: a 20 patients study

Emergency pericardiocentesis, guided by a two-dimensional echocardiography, was performed on twenty patients with symptomatic pericardial effusion of various types and causes. There were fourteen men and six women. The underlying causes were: primary lung cancer (6 cases), metastatic cardiac tumors (3 cases), tuberculosis (4 cases), complicated interventional procedures with cardiac chamber or vessel perforations (2 cases), dissecting aortic aneurysm (1 case), systemic lupus erythematous (1 case), idiopathic pericarditis (1 case), bacterial pericarditis (1 case), and myxedema heart disease (1 case). Seventeen cases were performed through the left xipho-sternal approach and 3 cases through the apical approach. None of the patients died as a result of these procedures. A two-dimensional echocardiogram is useful in diagnosing cardiac tamponade as well as in guiding pericardiocentesis, and obtaines highly positive results (20/20). The positive rate of pericardial fluid cytology for malignant cells was 89% (8/9), however, pericardial fluid cultures or direct smear for tuberculosis were negative (0/4). In cancer patients, the mean survival time following pericardiocentesis was 4.2 months (range, 1-7.8 months). We concluded that neoplastic involvement of the pericardium is the most frequent cause of symptomatic pericardial effusion. Pericardiocentesis assisted by a two-dimensional echocardiogram is safe and easy. In addition, pericarditis caused by TB is still significant and must be considered in every case in our nation.

Transesophageal echocardiography in adults with a continuous precordial murmur

In order to assess the ability of echocardiography in the detection of intracardiac and extracardiac shunts, we studied 11 patients (aged 22-64 yr) with a continuous precordial murmur using transthoracic and transesophageal echocardiography, and correlated the results with the subsequent angiographic and surgical findings. We found that only in 5 of 6 patients with a patent arterial duct could the continuous flow pattern be detected in pulmonary artery using transthoracic echocardiography, whereas it could be readily and accurately identified by transesophageal echocardiography in all patients. The diameters of the patent arterial duct were also measured and found to be in good correlation with subsequent surgical findings (r = 0.98, p less than 0.05). In 2 patients with a ruptured aneurysm of sinus of Valsalva which originated from the right coronary sinus and perforated into the right ventricle, transesophageal echocardiography gave a better image than transthoracic echocardiography. In 2 patients with coronary artery fistula, the origin and site of drainage of the coronary artery could be imaged using transesophageal echocardiography, but the course of coronary artery fistula was more easily detected by transthoracic echocardiography. In one patient with aortopulmonary window, the defect between ascending aorta and main pulmonary artery could readily be imaged by transesophageal echocardiography. We therefore recommend transesophageal echocardiography when evaluating patients with precordial continuous murmur in whom intracardiac and extracardiac shunts or defects are suspected.

A morphometric analysis of craniofacial growth in cleft lip and noncleft mice

Differences in face shape are considered a factor in cleft lip malformation. The purpose of this study was to analyze craniofacial growth in two strains: A/WySn with 28% cleft lip and C57BL/6J without cleft lip. Standardized photographs of 27 A/WySn and 25 C57BL/6J embryos with 34-46 somites (S) were taken in the superior, frontal, and lateral views. Landmarks were located and digitized for computerized analysis of growth change relative to somite number and at stages of face development before, during, and after primary palate closure. The results showed that both strains had similar overall growth patterns with increases in head width and face width, and decreases in nasal pit width. During early palatal closure in C57BL/6J mice, the nasal pit width was unchanged as brain width increased rapidly; and then later, the nasal pit width decreased as brain width increased slowly. However, during early closure in A/WySn mice, the nasal pit width decreased rapidly as brain width increased slowly; and then later, the nasal pit width was unchanged as brain width increased more rapidly. During early palatal closure, the narrower nasal pit width in A/WySn mice appeared to result from delayed growth of the supporting forebrain as the nasal pits become more medially positioned with normal face development. From the lateral view, the maxillary prominence depth was also smaller in the A/WySn strain during early palatal closure. This deficient forward growth of the maxillary prominences and the narrower positioning of the medial nasal prominences in A/WySn embryos appear to reduce the contact between the prominences and thus predispose this strain to cleft lip malformation.

Appendiceal US scans: histologic correlation

High-resolution in vitro ultrasonography (US) of 20 surgical appendiceal specimens was performed to compare appearances of appendiceal tissue at US with corresponding histologic features. With an articulated-arm system and micropositioner, precise spatial correlation was achieved. As elsewhere in the gastrointestinal tract, five distinct echo layers were observed. Normal and inflamed specimens demonstrated these layers, but the architecture became disorganized and indistinct in cases of appendicitis. Three measurements were made for each specimen: (a) overall cross-sectional diameter, including the lumen, (b) thickness of the submucosal echo layer, and (c) the combined thickness of both walls, excluding the lumen. For the inflamed specimens, a substantial increase in the thickness of the summed wall measurements was found. Wall US appearance alone may be misleading in differentiation of normal and abnormal appendices.

[Cation channels formed in lipid bilayer by Pinellia ternata lectin]

Pinellia ternata lectin (PTL), a protein exhibiting hemagglutination activity and carbohydrate binding specificity to mannan was purified from rhizome of Pinellia ternata. In this work the actions of PTL on artificial lipid bilayer were investigated by means of the two-compartment system of Mueller and Rudin. The lipid bilayer with resistance more than 10G omega was formed by a solution of lecithin and cholesterol (20 mg/ml and 5 mg/ml respectively) in N-decane. The electrical properties of the lipid bilayer were investigated in voltage clamp mode. Several minutes after the addition of PTL (2 micrograms/ml) in one compartment the channel-like noise as well as a decrease of the resistance of the bilayer were observed. These actions were inhibited by mannan significantly. The resistance increase of the bilayer with PTL-channels could be observed from 2G omega to control level (greater than or equal to 10 G omega) immediately after addition of 40 micrograms/ml mannan. The discrete conduction steps were recorded at low concentration of PTL and at low holding potential. The predominant unit conductance was 35pS in symmetric KCl solution of 100 mmol/L. The selectivity of PTL-channel was estimated from Goldman-Hodgkin-Katz equation by measurement of the reversal potential in an asymmetrical salt solution. The results showed that PTL-channels were cation selective.

Pronounced differences between native Chinese and Swedish populations in the polymorphic hydroxylations of debrisoquin and S-mephenytoin

The frequency of poor metabolizers of debrisoquin was low and similar in four different native Chinese nationalities. In a total sample of 695 Chinese subjects, only seven (1.01%) had a urinary ratio between debrisoquin and 4-hydroxydebrisoquin greater than 12.6, which is the antimode between poor metabolizers and extensive metabolizers in white populations. This is significantly lower than the 6.82% found in 1011 white Swedish healthy subjects (p less than 0.0001). Admixture analysis indicated the occurrence of two distributions within extensive metabolizers among both Chinese and white subjects. The mean of the distribution of metabolic ratios among Chinese extensive metabolizers was shifted toward higher values compared with Swedish extensive metabolizers (p less than 0.01). The frequency of poor metabolizers of S-mephenytoin was higher in 137 Chinese (14.6%) than in 488 Swedish (3.3%) subjects (p less than 0.0001). Our findings imply that drugs metabolized by these two polymorphic hydroxylases should be prescribed in different dosages to Chinese and white subjects.