Volume 114  ·   Issue 06  ·  2001

Objective To investigate the effects of continuous tracheal gas insufflation (CTGI) combined with biphasic intermittent positive airway pressure (BIPAP) ventilation on dogs with spontaneous breathing. Methods Eight canine models with oleic acid induced lung injury and spontaneous breathing were ventilated in a random order by Evita 2 (Drager Inc., Germany) in modes of BIPAP (BIPAP group) and BIPAP with CTGI flow rate of 3, 6 and 9 L/min (T3, T6 and T9 groups), respectively. The setting parameters of BIPAP were fiction of inspired oxygen 60%, inspiratory to expiratory ratio 1:1, respiratory rate 20 and positive end expiratory pressure 5 cm H2O. Arterial and mixed venous blood gas, lung mechanics, systemic and pulmonary hemodynamics status were monitored at the same level of PaCO2obtained by adjusting peak inspiratory pressure of BIPAP. Results Peak inspiratory pressure in the T6 group (14 ± 4 cm H2O) and in the T9 group (11 ± 3 cm H2O)were significantly lower than that of BIPAP (20 ± 5 cm H2O, P <0.01), but there was no significant difference among the T3, T6 and T9 groups or between the T3 and BIPAP groups. PaO2, mean artery blood pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, cardiac ouput,oxygen delivery and oxygen consumption all remained unchanged in four different conditions. Conclusions Using BIPAP combined with CTGI does not cause asynchrony between ventilator and spontaneous breathing, but significantly decreases airway pressure with no influence on hemodynamics and oxygenation. Therefore, BIPAP with CTGI may be a useful support technique, especially in cases where the airway pressure should be limited. Chin Med J 2001; 114 (6): 658-660

Objective To detect malaria DNA in mosquitoes. Methods A nested polymerase chain reaction (nested PCR) procedure which amplifies a 121 bp DNA of a SSUrRNA gene specific to Plasmodium vivax was used. Results In laboratory-infected mosquitoes, nested PCR could detect as few as 3 sporozoites or 1 infected mosquito mixed in a group of 99 normal ones. Furthermore, no specific 121 bp band was seen with DNA templates from other malaria parasites or negative mosquitoes. Conclusion Sensitivity and specificity obtained indicated an advantage of the nested PCR over DNA probes or direct PCR for the detection of Plasmodium vivax sporozoites in mosquitoes with low-grade parasitic infections. Chin Med J 2001; 114(6): 654-658

Objective To observe the efficiency and time course of gene expression and the safety of adenoviral vector mediated gene transfer in vivo. Methods After soaking soluble stents in a high concentration of glucose solution containing Adv5-CMV(cytomegalovirus) (control group) or Adv5-CMV/LacZ (treatment group) for 30 minutes, the stents were inserted into the lumina of cut rat carotid arteries and end-to-end anastomoses of the cut carotid were performed with standard microvascular surgical techniques. On days 2, 7, 14, 28, 60 and 90 after gene transfer, anastomotic arteries of the two groups were observed. On days 7 and 14, the ascending aortas,hearts, brains, livers, lungs, spleens and kidneys of the treatment group were observed. All samples were analyzed for the presence of β-galactosidase activity and histochemical staining. Results β-galactosidase activity was not detected in the carotid arteries of the control group and organs not directly exposed to adenoviral vector of the treatment group. The amount of β-galactosidase activity(× 10-3 U/g tissue) in the treatment group on the 2nd, 7th, 14th, 28th, 60th and 90th day after gene transfer was 3.87, 11.38, 9.8, 6.43, 3.18 and 2.43. respectively. Microscopic examination of sections from vessels of the control group and from the aortas, hearts, brains, livers, lungs, spleens or kidneys of the treatment group revealed no X-gal staining. Microscopic examination of carotid arteries of the treatment group revealed blue-staining in all anastomotic arteries and in all layers of the arterial wall observed on days 7 and 14 after gene transfer. Conclusion Adenoviral vector can effectively infect blood vessels in vivo. After adenoviral vector mediated direct gene transfer into anastomotic rat carotid arteries, recombinant gene expression began on day 2,peaked between days 7 and 14, prominently declined after day 28, and persisted at low levels more than three months. A recombinant gene could be delivered to a specific site by direct gene transfer in vivo by adenoviral vector infection. Chin Med J 2001; 114 (6): 650-653

Objective To explore the role of magnetic resonance imaging (MRI) in distinguishing malignant from benign pleural disease. Methods All 64 patients were examined with both computed tomography (CT) and MRI. The morphologic features of pleural lesions and MR signal intensity on T1-weighted, T2-weighted and contrast-enhanced T1-weighted images were evaluated. Results Mediastinal pleural involvement, circumferential pleural thickening, nodularity, irregularity of pleural contour, and infiltration of the chest wall and/or diaphragm were most suggestive of a malignant cause on CT and MR images. Contrary to what has been reported in the literature, pleural thickness greater than 1 cm either on CT or on MRI did not reveal a significant difference between malignant and benign pleural disease (P> 0.05, chi-square test). Using morphologic features in combination with signal intensity features, MRI had a sensitivity of 98%and a specificity of 92%in the detection of pleural malignancy. Conclusions Compared with those on CT, the morphologic features on MRI allowed a mostly equal and in some cases superior detection and evaluation of the spread of pleural disease. In combination with signal intensity and morphologic features, MRI is very useful in distinguishing malignant from benign pleural disease. Chin Med J 2001; 114(6): 645-649

Objective To discuss the value of cervical spine locking plate in anterior mono- segmental fusion. Methods Fifty cases of single level cervical diseases were treated by anterior decompression, auto-iliac bone graft, and AO cervical spine locking plate fixation. The average period of follow-up was 26 months, the bone graft fusion rate, maintenance of intervetebral height, and the complications of the hardware were observed. Results Forty-six cases were followed up; solid fusion were obtained in forty-five cases, with a fusion rate of 97.8%. The intervertebral height was maintained, and there were no complications related to plate and screw loosening,displacement or breakage. Conclusions Using cervical spine locking plate in anterior mono- segmental fusion could increase the fusion rate of bone grafts and maintain the intervertebral height to avoid the secondary neurologic defect resulting from the collapse of the vertebral body. The complications of the implants could be prevented by correct indications and precise surgical procedures.

Objective To investigate apoptosis induced by Toxoplasma gondii (T. gondii) in eyes of C57BL/6 (B6)mice. Methods Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) technique and pathological changes within eyes were analyzed at different time points after intraocular inoculation of either 50 or 500 of tachyzoites. Results In eyes that received 50 tachyzoites, a few apoptotic inflammatory cells in the anterior chamber and keratocytes in the cornea were seen at days 1 and 2, but no apoptosis was detected 4 days after inoculation. Significantly greater apoptosis of inflammatory cells was observed in the anterior chamber and in the vitreous of eyes injected with 500 parasites. Apoptosis of inflammatory cells in the anterior chamber and of keratocytes in the cornea was seen at day 1. The apoptotic stromal keratocytes strikingly increased at day 4. There were a number of apoptotic inflammatory cells in the vitreous at day 2, and a few apoptotic retinal cells along the internal limiting membrane and the nerve fiber layer of the retina 4 days after inoculation. Conclusion These results suggest that apoptosis of inflammatory cells infiltrated eye infected with this parasite may be a mechanism of eliminating the organism. Chin Med J 2001; 114 (6): 640-644

Objective To study the role of placental leptin in intrauterine cord leptin production and its relationship with neonatal anthropometry. Methods Forty women and their babies (40) were enrolled in this study. Placental tissues were assayed for leptin mRNA by reverse transcription/polymerase chain reaction (RT/PCR), and assayed for the obese gene protein leptin by Western-blot and immunohistochemistry. Blood was taken from the umbilical cord of the babies at delivery. Serum leptin was measured by radio-immunoassay. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between placental leptin, cord leptin and neonatal anthropometric measures. Results The obese gene was expressed in placental tissue at comparable or greater levels than that in adipose tissue. The placentas of the small for gestational age (SGA) neonates expressed leptin mRNA and protein at significantly lower levels than those of the appropriate for gestational age (AGA) neonates (P=0.0034 and 0.0076), while the placentas of the large for gestational age (LGA) neonates expressed leptin mRNA and protein at significantly higher levels than those of the AGA neonates (P=0.043 and 0.021). Linear regression analysis showed placental ob gene transcription and leptin translation correlated significantly with cord leptin (r=0.39 and 0.43), and neonatal Ponderal Index (r=0.66 and 0.69). Conclusion The placenta provides a source of leptin for the growing fetus, and this placental leptin might be a growth factor in intrauterine fetal development. Chin Med J 2001; 114 (6): 636-639

Objective To improve the diagnosis and treatment of aneurysms of anterior circulation. Methods 77 patients with 85 aneurysms of anterior circulation operated on from January 1990 to September 1997were analyzed retrospectively. 3D-CTA was used to detect and delineate aneurysms before and after operation. Improved operative techniques were used such as cranial base approaches, temporary artery occlusion, intra-aneurysm decompression, obliteration of aneurysms with multiple clipping, stepwise coagulation clipping, resection of aneurysms and so on. Results Outcome was considered good in 65 patients(85 %), fair in 6, poor in 3, and dead in 3. There was no postoperative death in patients with Hunt and Hess 0- Ⅲgrading. Conclusions 2D-CTA is useful in delineating the sharp,size, and neck of aneurysms, as well as its relation to near arteries and to cranial base structures. It is very helpful to improve the results of some special operative techniques for aneurysms of anterior circulation.

Objective To evaluate the incidence of deep venous thrombosis (DVT) after gynaecological laparoscopy. Methods The incidence of DVT was studied in 72 consecutive patients who underwent gynaecological laparoscopy in the Liverpool Health Service between May and September 1997. B-mode ultrasound supplemented by Doppler was used to examine venous patency and intraluminal echoes to diagnose DVT. Sixty-one patients who had pneumoperitoneum less than 60 minutes were classified a minor procedure and 11 who had pneumoperitoneum more than 60 minutes were classified as major procedure. Two Doppler ultrasound scans were planned for every patient. The first one was done within 24 hours and the second was performed on day 7 post-surgery. All 72 patients had the first scan and 40 out of 61 in the minor procedure group and 9 out of 11 in the major procedure had the second scan. Twenty-three patients who did not come for the second scan were followed up by phone. Results No DVT was found in our study. Conclusion This study confirms an impression that gynaecological laparoscopic procedure has a very low incidence of DVT. If it occurs, the diagnosis and treatment must be made as soon as possible so that the fatal complications such as pulmonary embolus can be avoided. Chin Med J 2001; 114(6): 632-635

Objective To investigate the mechanism of prolonged uterine hemorrhage after terminating early pregnancy by mifepristone plus misoprostol. Methods Forty-five decidua specimens were obtained from 45 pregnant women with amenorrhea of 6 - 7week duration. Fifteen women were treated with mifepristone and 15 were treated with mifepristone plus misoprostol. The remaining 15 served as controls. The tPA and PAI-1 mRNA levels were estimated by reverse transcription-polymerase chain reaction. Chromogenic assay and enzyme-linked immunosorbent assay were used to detect tPA activity and PAI-1 protein level in decidua. Results The activities of tPA in the mifepristone plus misoprostol group and in the mifepristone group were 46.91 ± 20.74 IU/mg • protein and 64.25 ±35.81 IU/mg • protein respectively, lower than those in the normal decidua group (99.76 ±58.61 IU/mg·protein, P <0.05). tPA mRNA levels in the mifepristone plus misoprostol group were the highest (1.43± 0.39) among the groups. In the mifepristone group, tPA mRNA level (0.90 ± 0.16) was not significantly different from that in the normal decidua group (0.94 ±0.17). The protein and mRNA expression levels of PAI-1 were not significantly different among the three groups (P>0.05). Conclusions Mifepristone plus misoprostol decreased tPA activity in human early decidua by post-transcription pathways, which may influence decidua shedding, endometrial angiogenesis, endometrial remodeling, and cause prolonged uterine hemorrhage after drug abortion. Chin Med J 2001; 114(6): 628-631

Objective To analyze the results of 18 patients with giant aneurysms of anterior circulation retrospectively. Methods In the patients who had been surgically treated, direct clipping of the aneurysm was accomplished in 11patients, aneurysm trapping or removal after trapping in 4,aneurysm excision or trapping with parent artery anastomosis in 2, and aneurysm wrapping in 1. Results Early postoperative neurological function was evaluated according to Glasgow Outcome Scale. The 11patients having direct clipping of the aneurysm and 2patients receiving aneurysm excision or trapping with parent artery anastomosis gained good recovery except one who had preoperative IV grade according to Hunt and Hess grades after SAH and had severe disability postoperatively. In 4patients with aneurysm trapping or excision after trapping,one experienced temporary contralateral hemiparesis, and another patient had hemorrhage in the operative field and recovered smoothly after a second operation for hematoma. One patient with aneurysm wrapping died from postoperative aneurysm rebleeding. Conclusions Direct clipping is preferred for giant intracranial aneurysm, Unclippable aneurysm require alternative methods that compromise parent arteries and need revascularization to restore sufficient cerebral blood flow.