Assessment of the functional significance of coronary artery stenosis by dobutamine-atropine stress echocardiography

This study was performed to evaluate whether dobutamine stress echocardiography (DSE) can provide any additional information regarding the location and severity of coronary artery disease (CAD) in an individual patient. DSE was performed in 233 patients with clinical manifestations of angina pectoris. There were 162 patients with angiographically documented CAD defined as > or = 50% diameter stenosis. The severity of coronary lesions was divided into three groups: 50-75, 76-90 and >90%. The diagnostic sensitivity in detecting left anterior descending artery (LAD) and right coronary artery (RCA) lesions was higher for lesion severity of>90% than of 50-75% (p = 0.01 for LAD and p < 0.05 for RCA). The diagnostic sensitivity in detecting CAD was highest among patients with proximal coronary lesions (89% for LAD, 64% for the left circumflex artery, and 81 % for the RCA). When lesion severity increased from 50-75 to >90%, wall motion scores at peak dose during dobutamine infusion increased from 12.3 +/- 4.3 to 18.4 +/- 5.4 (p = 0.003) in the proximal LAD lesion group and from 10.6 +/- 2.0 to 20.4 +/- 5.9 (p < 0.0001) in the mid-distal LAD lesion group. When lesion severity increased from 50-75 to >90%, wall motion scores at peak dose increased from 5.9 +/- 2.0 to 8.0 +/- 2.5 (p < 0.05) in the proximal RCA lesion group and from 5.2 +/- 2.1 to 8.1 +/- 1.9 (p < 0.05) in the mid RCA lesion group. However, the change in wall motion scores did not reach statistical significance in proximal and distal lesions of the left circumflex artery when lesion severity increased from 50-75 to >90%. The correlation coefficient between quantitative wall motion score and Gensini's score was 0.54 (p = 0.0001) in all patients and 0.6 (p = 0.0001) in patients without myocardial infarction. In conlcusion, the functional significance of lesion severity and distribution can be evaluated by DSE. Regional dyssynergy of LAD and RCA territories during peak-dose dobutamine infusion was most apparent at the stenotic level >90%.

Dobutamine stress echocardiography compared with exercise thallium-201 single-photon emission computed tomography in detecting coronary artery disease-effect of exercise level on accuracy

Dobutamine stress echocardiography (DSE) and exercise thallium-201 single-photon emission computed tomography (SPECT) were compared for the accuracy in detecting coronary artery disease (CAD) in 51 consecutive patients. Twenty-six (group 1) of the 51 patients achieved adequate exercise end points, and 25 (group 2) did not. There were 38 patients with angiographically documented CAD. The overall sensitivity of DSE and thallium-201 SPECT in detecting CAD was 92 and 76% (p = NS), and the specificity was 77 and 77% (p = NS), respectively. The sensitivity of DSE is the same as that of SPECT in group 1 (90 vs. 90%; p = NS) and higher than that of SPECT in group 2 (94 vs. 61%; p < 0.05). In patients with CAD without a history of acute myocardial infarction or pathological Q wave on resting electrocardiogram, the sensitivity of DSE is the same as that of SPECT in group 1 (82 vs. 82%; p = NS) and also higher than that of SPECT in group 2 (90 vs. 40%; p = 0.03). The sensitivity in detecting individual coronary artery lesions with DSE and thallium-201 SPECT was not affected by the exercise level. The agreement between DSE and thallium SPECT in detecting patients with CAD was 88% in group 1 (kappa = 0.69; p < 0.001) and 76% in group 2 (kappa = 0.45; p = 0.01). The agreement in detecting vascular territories with ischemia was 68% in group 1 (kappa = 0.30; p < 0.01) and 75% in group 2 (kappa = 0.33; p < 0.001). The agreement in detecting vascular territories with a scar was 87% in group 1 (kappa = 0.55; p < 0.001) and 85% in group 2 (kappa = 0.44; p < 0.001). In conclusion, the sensitivity and specificity of DSE in detecting CAD are similar to that of thallium-201 SPECT with an exercise level > or =85% of the maximal predicted heart rate. However, in patients who cannot exercise adequately, DSE is more accurate than thallium SPECT. The agreement between DSE and thallium SPECT in detecting patients with CAD and identifying ischemia of individual vascular territories is also affected by the exercise level.

Optimal surgical strategy for potentially curable serosa-involved gastric carcinoma with intraperitoneal free cancer cells

BACKGROUND

Radical gastrectomy with systematic lymphadenectomy (RG) remains controversial in the treatment of gastric carcinoma. On the other hand, the prognosis of gastric carcinoma, in the presence of intraperitoneal free cancer cells, is poor. The optimal surgical strategy for serosa-involved gastric carcinoma with intraperitoneal free cancer cells remains undefined.

STUDY DESIGN

A prospective study of intraperitoneal cytologic washing was conducted on 134 patients with potentially curable serosa-involved gastric carcinoma who underwent RG. During the same period, 28 patients with resectable tumors who received palliative simple gastrectomies because of the presence of gross incurable conditions (eg, multiple hepatic metastases, peritoneal carcinomatosis, or extra-abdominal metastasis) were used as controls.

RESULTS

Intraperitoneal free cancer cells were found in 26 patients (19.4 percent). Compared with the remaining 108 patients without free cancer cells, there were no significant differences in the clinicopathologic characteristics and pathologic stages. No patients died after palliative resection, but five patients died after RG. The patients with free intraperitoneal free cancer cells had a poorer long-term prognosis after RG than those without free cancer cells (p < 0.0001). The prognosis for such patients was similar to the prognosis of those who underwent palliative resection.

CONCLUSIONS

A peritoneal washing cytologic examination is mandatory before resection for potentially curable serosa-involved gastric carcinoma. When free cancer cells appear in the washing fluid, the cancer is incurable. Simply gastrectomy without additional lymphadenectomy is the optimal strategy for treatment.

Sarcomatoid carcinoma of the small intestine: a case report

Sarcomatoid carcinoma of the small intestine is a very rare tumor. Only limited cases have been reported in the literature. The tumor is more malignant than the usual adenocarcinoma of the small intestine. Here we report a 59-year-old female patient who was referred from a local hospital after suffering persistent hematochezia, abdominal pain and distention for three months. Because of persistent intestinal obstruction and bleeding, reoperation at our hospital was performed. A huge tumor, originating from the ileum and with multiple liver and bone metastasis, was found. Palliative resection of the tumor with two segments of the small intestine and sigmoid colon was carried out. Pathology confirmed the diagnosis of sarcomatoid carcinoma. She died two months after operation.

Quantitative competitive polymerase chain reaction for detection and quantification of infectious bursal disease virus cDNA and RNA

A polymerase chain reaction (PCR)-based method to measure complementary DNA (cDNA) and RNA levels of infectious bursal disease virus (IBDV) was developed. Quantification was achieved by quantitative competitive PCR (QC-PCR) amplification. A competitor, a deletion mutant of the wild type IBDV cDNA, was 10-fold serially diluted and co-amplified with IBDV cDNA after being reversely transcribed from the viral RNA. After agarose gel electrophoresis, staining, and densitometric scanning, the bands on the digitized images were analyzed and quantified by computer-assisted image analysis. Complementary DNA of standard, as well as variant strains, of serotype 1 IBDV was detected and quantified using the same QC-PCR procedures. The assay could measure IBDV cDNA levels ranging from 1 microgram to 45 fg and RNA levels ranging from 9 micrograms to 45 fg. The results indicated that QC-PCR is sensitive, easy to perform, and suitable for routine quantitation of IBDV cDNA or RNA levels.

Beneficial effects of dantrolene on lipopolysaccharide-induced haemodynamic alterations in rats and mortality in mice

We investigated the effect of dantrolene, an inhibitor of Ca2+ release from the sarcoplasmic reticulum, on the induction of nitric oxide (NO) synthase II by bacterial endotoxin (lipopolysaccharide) in the anaesthetised rat and on survival in a murine model of severe endotoxaemia. Injection of lipopolysaccharide (i) induced biphasic changes of rectal temperature and blood glucose: an initial increased phase (< 180 min after injection of lipopolysaccharide) followed by a decreased phase (at 240-360 min), (ii) caused a fall in mean arterial blood pressure from 115 +/- 3 mmHg (time 0) to 83 +/- 6 mmHg at 360 min, (iii) resulted in a substantial hyporeactivity to noradrenaline (1 microg/kg i.v.), (iv) raised plasma nitrate (an indicator of NO formation) in a time-dependent manner, (v) elicited a significant increase in NO synthase II activity in the lung and (vi) caused a 80% lethality (in mice). Pretreatment of animals with dantrolene not only attenuated the delayed circulatory failure, but also prevented the overproduction of NO and the induction of NO synthase II caused by lipopolysaccharide in the rat, and improved survival in a murine model of severe endotoxaemia. Thus, dantrolene has beneficial haemodynamic effects in animals with endotoxin shock. We propose that a decrease of free cytosolic Ca2+ levels plays an important role in the prevention of NO synthase II induction.

Accuracy of the conductance catheter for measurement of ventricular volumes seen clinically: effects of electric field homogeneity and parallel conductance

The conductance-volume method is an important clinical tool which allows the assessment of left ventricular function in vivo. However, the accuracy of this method is limited by the homogeneity of electric field the conductance catheter produces and the parallel conductance of surrounding structures. This paper examines these sources of error in volumes seen clinically. The characteristics of electric field within a chamber were examined using computer simulation. Nonconductive and conductive models were constructed and experimental measurements obtained using both single-field (SF) and dual-field (DF) excitation. Results from computer simulations and in vitro measurements were compared to validate the purposed theoretical model of conductance-volume method. The effects of field homogeneity and significance of parallel conductance in volume measurement were then determined. The results of this study show that DF provide a more accurate measure of intraventricular volume than SF, especially at larger volumes. However, both significantly underestimate true volume at larger volumes. In addition, the parallel conductance due to the chamber wall is significant at small volumes, but diminishes at larger volumes. Furthermore, the effect of parallel conductance beyond the chamber wall may be negligible. This study demonstrates the limitations in applying current conductance technology to patients with dilated hearts.

Evaluation of a heterologous metallothionein gene promoter in transfected mosquito cells

Mosquito cells from the C7-10 Aedes albopictus line were transfected with a recombinant plasmid containing the Escherichia coli galactokinase gene under control of the promoter from the Drosophila melanogaster metallothionein gene, Mtn. Consistent with what has been observed with heterologous metallothionein promoters in several vertebrate systems, treatment of transiently transfected mosquito cells with CuSO4 or CdCl2 induced a 2- to 5-fold increase in galactokinase gene expression. Levels of enzyme activity were not increased in tests using stably transformed lines despite wide ranges in the number of transfected gene copies detected in Southern blots. The importance of comparative studies with gene constructs that may eventually be used to produce genetically modified mosquitoes is underscored by the apparent variability in activity of heterologous promoters from D. melanogaster in different mosquito cell lines.

Retained vaginal gauze with unusual complication: a case report

We report a case of a postpartum retained vaginal gauze which migrated to the bladder and presented as a bladder stone. The patient had received numerous clinical evaluations for her chronic abdominal pain, of all which failed to detect or indicate the presence of retained gauze. Retained surgical gauze is a preventable problem but continues to occur periodically. Prevention remains the key to this problem. The gauze packed within the vagina either after transvaginal surgery or delivery should be cared for as in other parts of the body. Though extremely rare, retained surgical gauze should be considered in the differential diagnosis in postpartum patients with chronic abdominal pain, irritable bladder symptoms or pelvic abscess.

Localizing individual coronary artery obstructions with the dobutamine stress echocardiography

The diagnostic accuracy of detecting individual coronary artery lesions using dobutamine stress echocardiography was evaluated in 206 patients with clinical manifestations of agnina pectoris. The sensitivity, specificity, and accuracy in detecting individual coronary artery lesions was described. The sensitivity was higher in the single-vessel group than in the double- or triple-vessel group. Furthermore, the sensitivity of dobutamine stress echocardiography in localizing vascular territories was greater for proximal segment lesions than for distal segment lesions. The increment of total score and score index at peak dose did not reach statistical significance between the left main lesion and the double-vessel lesions of left anterior descending artery and left circumflex artery (4.88 +/- 1.44 vs. 3.79 +/- 0.39, nonsignificant; 0.83 +/- 0.25 vs. 0.54 +/- 0.06, nonsignificant). In conclusion, although dobutamine stress echocardiography is sensitive for diagnosing coronary artery disease, localizing individual coronary artery lesions is less sensitive for triple-vessel disease and distal lesions.

Inhibition of platelet adhesion to collagen by cGMP-elevating agents

In the present study, we examined the effects and action mechanisms of cGMP-elevating agents on platelet adhesion to collagen fiber. YC-1, a nitric oxide (NO)-independent activator of soluble guanylate cyclase, inhibited both initial and long-term platelet adhesion to collagen, and the inhibitory effect was potentiated by dipyridamole, a selective inhibitor of cGMP-specific phosphodiesterase. Sodium nitroprusside (SNP), a NO-donor, and 8-bromo-cGMP also inhibited the initial platelet adhesion, but inhibited long-term adhesion only in the presence of dipyridamole. Collagen-induced intracellular Ca2+ mobilization and actin polymerization were prevented by YC-1, SNP and 8-bromo-cGMP. Since blockade of Ca2+ mobilization and actin polymerization caused by collagen led to decrease of platelet adhesion, we suggest that the inhibitory activity of cGMP-elevating agents on the adhesion of platelets to collagen is resulting from interference of these signaling pathways.

YC-1, a nitric oxide-independent activator of soluble guanylate cyclase, inhibits platelet-rich thrombosis in mice

YC-1 (3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole), a nitric oxide (NO)-independent activator of soluble guanylate cyclase, has been shown to inhibit platelet activation and aggregation in vitro through the generation of cGMP. In the present study, we assessed the antithrombotic effect of YC-1 in models of experimental thrombosis in mice. YC-1 (10, 30 micrograms/g, i.p.)-treated mice showed a prolonged tail bleeding time 30 min after injection (from control 91.0 +/- 6.4 s to 208.6 +/- 22.7 s and 291.8 +/- 42.4 s, respectively). In contrast, aspirin at a dose of 30 micrograms/g (i.p.) prolonged the bleeding time to more than 600 s. Platelet-rich thrombus formation was induced by irradiation of the mesenteric venule with filtered light in mice pretreated intravenously with fluorescein sodium. YC-1 (30 micrograms/g, i.p.) markedly prolonged the occlusion time of irradiated venules (from control 146.1 +/- 19.0 s to 275.6 +/- 24.5 s) in heparinized (1 U/g) mice. In the same condition, aspirin (100 micrograms/g) only slightly prolonged the time required for occlusion (193.2 +/- 13.2 s). In a model of fatal pulmonary thromboembolism induced by intravenous injection of ADP (300 micrograms/g), YC-1 was effective in reducing mortality when administered intraperitoneally at doses of 10-30 micrograms/g. The antithrombotic effect of YC-1 was correlated with the inhibition of ADP-induced platelet aggregation ex vivo. In contrast, aspirin (30, 100 micrograms/g) did not inhibit ADP-induced pulmonary thromboembolism in vivo or platelet aggregation ex vivo. YC-1 (3, 10 micrograms/g) also exhibited profibrinolytic activity ex vivo, as revealed by shortening of the euglobulin clot lysis time. Therefore, YC-1 is an effective antithrombotic agent in preventing thrombosis in animal models, and its antiaggregating and additional profibrinolytic effects may be of potential clinical benefit in the treatment of thromboembolic diseases.

Myocardial stunning after cerebral infarction

Myocardial stunning has not been described in patients with cerebrovascular accidents. We present a patient in whom inferior wall hypokinesis, ST-segment elevations and Q waves developed after acute right hemisphere ischemic stroke. Total recovery ensued within 5 days. Coronary vasospasm induced by stroke-related sympathetic surge might be the cause of this cardiac event.

Role of nitric oxide in lipopolysaccharide-induced mortality from spontaneously hypertensive rats

To investigate whether nitric oxide (NO) contributed to a higher mortality induced by lipopolysaccharide (LPS) in spontaneously hypertensive rats (SHR), NO synthase inhibitors were used to examine the mortality from LPS in SHR and normotensive Wistar-Kyoto (WKY) rats. We evaluated the mortality from LPS in a series of doses (5, 10, or 20 mg/kg, i.v.) in the anesthetized rat. Plasma nitrite was measured before and at 1, 2, and 3 h after treated rats with LPS (5 mg/kg, i.v.). Pressure responses to N omega-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine (AG) were performed in rats treated with or without LPS for 3 h. Thoracic aortic cyclic guanosine 3',5'-monophosphate (cGMP) levels were also assessed. Our results demonstrated that injection of LPS caused a dose-dependent mortality in both strains, having a more marked effect in SHR. The survival time of rats after injection of LPS (5 mg/kg, i.v.) was much shorter in SHR. A higher basal level of plasma nitrite was observed in SHR and this difference was further augmented by LPS. The administration of L-NAME (3 mg/kg, i.v.) and AG (15 mg/kg, i.v.) 3 h after LPS had no significant effects on the survival time of WKY rats, but significantly prolonged that of SHR to a similar time of WKY rats. The injecton of L-NAME prior to LPS increased blood pressure of WKY rats by 28+/-5 mmHg and increased that of SHR by 38+4 mmHg. At 3 h after LPS, L-NAME had a greater pressor effect in SHR than in WKY rats. By contrast, before rats injected with LPS, AG slightly increased blood pressure of SHR by 7+/-3 mmHg but not of WKY rats (3+/-2 mmHg), whereas it also had a greater pressor effect in SHR than in WKY rats after treated rats with LPS for 3 h. In addition, LPS induced a higher level of cGMP in SHR than in WKY rats, which was attenuated by in vitro treatment of aortic rings from LPS-rats with L-NAME or AG to a similar level in SHR and WKY rats. These results suggest that a higher level of NO evoked by LPS is associated with a higher mortality in SHR and we propose that the elevated NO synthesis in SHR may play an important role in the compensatory mechanisms activated to combat the hypertensive state.

Co-administration of midazolam decreases propofol dose during anesthesia in endoscopic laryngeal microsurgery

BACKGROUND

Propofol is commonly used in total intravenous anesthesia (TIVA) for brief surgical procedures because it offers rapid recovery and has fewer side effects. However, concomittent use of other adjuvant agents has been considered so that the same anesthetic effects can be achieved at lower doses of propofol which is more expensive without compromising rapid recovery and increasing the adverse effects. This study was therefore designed to evaluate the co-administration of midazolam and propofol during anesthesia for endoscopic microsurgery and test its influences on the consumption of propofol and the quality of anesthesia.

METHODS

Forty-two patients receiving selective endoscopic microsurgery were enrolled in this study. All patients received high frequency jet ventilation (HFJV) under TIVA. The control group (n = 21) received propofol (20 mg/5 s) during induction and 10 mg/kg/h as maintenance. The study group (n = 21) received midazolam (0.06 mg/kg) and propofol (20 mg/5 s) for induction with propofol 8 mg/kg/hr for maintenance. Doses of propofol, vital signs, recovery time, post-anesthetic high cortical function, and adverse events were evaluated and compared.

RESULTS

Co-administration of midazolam and propofol in TIVA could reduce the induction dose and the total dose of propofol by 51% and 26% respectively but still achieve the same anesthetic effects. Vital signs and recovery were not influenced, and incidence of adverse effects did not increase.

CONCLUSIONS

Our result suggests that co-administration of midazolam and propofol in TIVA appears to be safe, effective, and economic alternative to that with propofol alone. The effects were synergic but side effects were not.

Evidence for inducible nitric oxide synthase in spontaneously hypertensive rats

This study investigates the mechanism of the production of nitric oxide (NO) caused by lipopolysaccharide (LPS) in spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats. The injection of LPS (5 mg/ kg, i.v.) caused a mild hypotension in WKY rats, while it induced a more severe hypotensive effect in SHR. The basal level of plasma nitrite was slightly higher in SHR than in WKY rats. At 3 h after injection of LPS, the increment in plasma nitrite was more significant in SHR. Prior to the treatment of rats with LPS, the plasma level of tumor necrosis factor-alpha (TNF alpha) was also higher in SHR than in WKY rats, and LPS induced a more significant increase of TNF alpha level (at 1 h) in SHR. In rats treated with LPS, acetylcholine-induced relaxation was significantly impaired in thoracic aortic rings obtained from WKY rats, but not in those from SHR. By contrast, L-arginine (1 mM) did not cause any relaxations in rings without the endothelium obtained from WKY rats while it slightly relaxed those from SHR, and this difference was further augmented by treatment of rats with LPS for 3 h. In addition, the basal cGMP level was higher in SHR, which was inhibited by aminoguanidine (AG, 1 mM). The treatment of rats with LPS further increased the formation of cGMP in both strains and this increment was greater in SHR than in WKY rats, which was also attenuated by AG to a similar level between both strains. Interestingly, an expression of inducible NO synthase (NOS II) protein was only observed in SHR, and further enhanced by treated rats with LPS. We conclude that an increased production of NO in SHR, which was further enhanced by LPS, is attributed to a basal expression of NOS II.

Characterization of the reaction rate coefficient of DNA with the hydroxyl radical

Using agarose gel electrophoresis, we have measured the yield of single-strand breaks (SSBs) induced by 137Cs gamma irradiation in a variety of plasmid DNA substrates ranging in size from 2.7 kb to 38 kb irradiated in aerobic aqueous solution in the presence of the hydroxyl radical scavenger dimethyl sulfoxide (DMSO). Under these conditions DNA SSBs are caused mainly by the hydroxyl radical. Using the competition between DMSO and DNA for the hydroxyl radical, we have estimated the rate coefficient for the reaction of the hydroxyl radical with DNA. The results cannot be characterized by conventional steady-state competition kinetics. However, it is possible to describe the second-order rate constant for the reaction as a function of the scavenging capacity of the solution. The second-order rate constant increases with increasing scavenging capacity, rising from about 5 x 10(8) dm3 mol-1 s-1 at 10(5) s-1 to about 10(10) dm3 mol-1 s-1 at 10(10) s-1. This dependence of the second-order rate constant on the scavenging capacity appears to be more pronounced for larger plasmids.

Bacterial translocation in the course of acute pancreatitis: beneficial role of nonabsorbable antibiotics and lactitol enemas

Two-hundred Wistar rats were allocated to 4 groups. The groups, 3 representing our acute pancreatitis model induced by intrabiliary injection of a trypsin/enterokinase mixture, were studied as follows: (A) no treatment; (B) given a daily 30-ml enema with 20 mg/kg rifaximin; (C) given a daily 30-ml enema with 20 mg/kg rifaximin plus lactitol 0.5 g/kg, and (D) given a daily 30-ml enema with warm saline. A further group of healthy rats was given an intrabiliary injection of 0.15 ml saline. Sacrifices were made after 6, 12, 24, 48 and 72 h of observation. Serial blood samples were drawn to measure pancreatic enzymes and endotoxin. At sacrifice, ascites, lymph nodes, pancreas, spleen, portal vein blood, arterial blood and bile were obtained for bacteriological culture. Both enema treatments brought about a significant improvement in survival. Enema treatments did not affect the serum level of pancreatic enzymes. A time-course increase in endotoxin level was observed in untreated rats. However, significantly decreased levels were observed after both enema treatments. Overall, ascites was the sample most frequently infected. Lymph nodes contiguous to the gut were found to be infected more frequently than those close to major vessels. The histological pancreatic damage was of a significantly lesser degree in both enema treatment groups. Virtually all severe necrotico-hemorrhagic pancreatic lesions were associated with bacterial infection. These data suggest that bacterial translocation plays a relevant role in the outcome of experimental necrotizing pancreatitis. Intra-abdominal spread and lymphatics seem to be the pathways most likely involved in such processes. Colonic cleansing by non-absorbable antibiotics and lactitol seems to exert a beneficial effect on the supervening infection of experimental necrotizing pancreatitis.

Neonatal capsaicin treatment alters the metabolic activity of subcortical somatosensory structures of developing rats in response to whisker stimulation

Sprague-Dawley rats neonatally treated with capsaicin exhibited significant changes in 2-deoxy-glucose uptake in the subcortical somatosensory structures following repetitive whisker deflection. There was an increased uptake in the spinal trigeminal nucleus pars caudalis and a decrease in the principal sensory nucleus and the ventral posteromedial thalamic nucleus. The present study suggests that disruption of nociceptive afferents during development causes functional changes to subcortical somatosensory trigeminal nuclei.

Biomechanical analysis of location of lag screw of a dynamic hip screw in treatment of unstable intertrochanteric fracture

OBJECTIVE

The aim of this study was to assess the most adequate location of a lag screw of a dynamic hip screw in the treatment of an unstable intertrochanteric fracture.

METHODS

Six pairs of proximal femora obtained from fresh adult cadavers were inflicted with iatrogenic unstable intertrochanteric fractures. Fractures of both sides were stabilized with two different favored locations of a lag screw and tested by a Material Testing System machine with increased loads to evaluate the relative migration of the femoral head.

RESULTS

There was significant difference (p < 0.05) with less migration of the femoral head by inferior insertion of a lag screw in the frontal plane and central insertion in the coronal plane.

CONCLUSIONS

Based on theoretical and experimental considerations, the most adequate location of a lag screw of a dynamic hip screw should be inferior in the frontal plane and central in the coronal plane.

Methylperoxyl radicals as intermediates in the damage to DNA irradiated in aqueous dimethyl sulfoxide with gamma rays

Using agarose gel electrophoresis, we have measured the yields of DNA single-strand breaks (SSBs) for plasmid DNA gamma-irradiated in aerobic aqueous solution. Incubation after irradiation with the base damage repair endonucleases formamidopyrimidine-DNA N-glycosylase (FPG) or endonuclease III (endo III) results in an increase in the yield of SSBs. In the absence of dimethyl sulfoxide (DMSO) during irradiation, this increase is consistent with the yields of known substrates for FPG and endo III as determined by gas chromatography/mass spectrometry. After irradiation in the presence of 1 mol dm-3 DMSO, the increase in the yield of SSBs after enzyme incubation was further enhanced by a factor of about 5 to 7. The magnitude of this effect, the inability of acrylamide or oxygen to suppress it, and its attenuation by N,N,N',N'-tetramethylphenylenediamine (TMPD) or glycerol all suggest that the methylperoxyl radical (derived from DMSO) is involved as an intermediate. Reactions of the methylperoxyl radical (or some other species derived from it) do not result in strand break damage, but are responsible for DNA base damages which are recognized by FPG and endo III.

Diagnosis of mucopolysaccharidosis type IIIB

Mucopolysaccharidosis (MPS) includes a group of lysosomal storage diseases. Among them, type III (Sanfilippo) disease is rarely described in Taiwan because of their complexity. With accurate quantifying and precise separation of urinary glycosaminoglycans (GAGs), and specific enzyme measurements, two cases of MPS IIIB disease were able to be described. They both had mild-to-moderate degrees of mental retardation, facial dysmorphism and dysostosis multiplex which do not differ from other types of MPS. Total amounts of GAGs in the urine were only mildly elevated but, among them, heparan sulfate was the highest. Skin fibroblasts alpha-N-acetyl-glucosaminidase activities were low in both cases. Therefore, analysis of GAGs and enzyme assays are important for the diagnosis of patients suspected to have MPS, especially type III disease.

Inoue balloon deformity and rupture during percutaneous balloon valvuloplasty

In the management of mitral stenosis, similar long-term results can be obtained by using either an Inoue balloon catheter or a double-balloon technique for percutaneous balloon valvuloplasty. There have been few reports concerning any deformity of an Inoue balloon. From January 1988 to June 1995, 263 procedures of either mitral or tricuspid valvuloplasty have been performed in this center. The Inoue balloon catheter technique was used for 245 procedures. A deformity of the Inoue balloon catheter was noted in 4 (1.6%) and actual rupture of deformed balloon occurred in one (0.4%). All deformities were found at the distal portion of the Inoue balloon. Valvular insufficiency became more severe after valvuloplasty in two cases. Following rupture of the balloon, neither arterial embolization nor perforation of the cardiac chambers developed. In conclusion, a deformity of the Inoue balloon, although rare, can develop during percutaneous balloon valvuloplasty. The deformity may portend balloon rupture if additional maximal dilatations are undertaken.