[Determination of 4-methyl-2-pentanol in workplace air by solvent desorption-gas chromatography].

Objective: To establish a method for the determination of 4-methyl-2-pentanol in the air of workplace by gas chromatography. Methods: In January 2022, 4-methyl-2-pentanol in the air of workplace was collected by activated carbontube, eluted with dichloromethane-methanol (95∶5, V/V), separated by capillary column and determined by gas chromatogram. Results: The limit of detection for 4-methyl-2-pentanol was 0.04 µg/ml. The linear range of 4-methyl-2-pentanol was 0.16-1616.60 µg/ml, with the regression equation of y=1.94x-5.48, and the coefficient correlation was 0.99958, and the minimum detection concentration was 0.03 mg/m(3) (collected sample volume was 1.50 L). The within-run precisions were 1.08%-1.75% and the between-run precisions were 1.41%-2.52%. The desorption rates were 95.15%-99.91%. The samples could be stored at least 3 days at room temperature and 7 days at 4 ℃ without significant loss. Conclusion: The method has the advantages of good precision, high sensitivity and simple operation. It is suitable for the determination of 4-methyl-2-pentanol in the air of workplace.

Effects of warm blood cardioplegic solution on myocardial protection.

To evaluate the effects of warm blood cardioplegic solution on myocardial protection, normothermic induction and terminal perfusion of oxygenated blood cardioplegia in combination with intermittent administration of cold blood cardioplegia during ischemia were studied in an isolated working rat heart model. The experimental protocol consisted of a 120 min cardioplegic arrest followed by 45 min normothermic reperfusion. Myocardial content of adenosine triphosphate (ATP), recovery of the left ventricular function, release of creatine phosphokinase (CPK) and ultrastructure of myocardium were assessed before and after ischemia. The results showed that the hearts preserved with warm blood cardioplegic induction and terminal perfusion had significantly higher levels of ATP, better recovery of cardiac function and lower releases and lower releases of CPK than those receiving cold blood cardioplegia alone, with myocardial tissue being of generally normal structure. These findings suggest that warm induction and terminal perfusion of blood cardioplegic solution can accelerate myocardial metabolic and functional recovery, preserve high-energy phosphate, reduce myocardial injury and enhance myocardial protection.

Correction of corrected transposition of the great arteries associated with cardiac anomalies.

Reported in this paper are 8 cases of corrected transposition of the great arteries associated with anomalies. All the patients underwent the repair of the ventricular septal defect and atrial septal defect, the replacement of left-side tricuspid value, the pulmonary valvotomy and the placement of extra-cardiac conduit to the pulmonary trunk respectively with no hospital death after operation. The paper also described the selection of the heart incision, the prevention of injury of the conduction system and indication of the placement of extra-cardiac conduit.

Delay of the excision of UV light-induced DNA adducts is involved in the coclastogenicity of UV light plus arsenite.

Chromatid exchanges and chromatid breaks were synergistically increased by a 2-h post-treatment with arsenite (VS treatment) but not with arabinofuranosyl cytosine (VA treatment) of UV-irradiated late-G1 Chinese hamster ovary cells. In order to determine the mechanism of this UV-arsenite coclastogenicity, we have compared the effects of arsenite and arabinofuranosyl cytosine on the generation of DNA strand breaks in UV-irradiated cells by alkaline elution and alkaline sucrose sedimentation. Only very small numbers of DNA breaks were detected immediately after VS treatment, however the breaks in parental strands increased as the cells reached mitosis in drug-free medium, whereas a large number of breaks were detected immediately after VA treatment but the breaks decreased thereafter. By labelling the newly synthesized DNA, we have also shown that the VS-treated cells had more breaks in daughter strands than the VA-treated cells at the time of reaching mitosis. The effect of a 2-h post-treatment with arsenite on the excision of UV-induced DNA adducts was further investigated by using the exponentially growing cells. The results confirmed that very low amount of breaks was detectable immediately after VS treatment, however the amount of breaks increased upon the removal of arsenite. Therefore, the breaks in the daughter strands of VS-treated cells may come from DNA replication using templates containing unexcised adducts, or using broken templates. It is conceivable that gaps in the overlapping regions of parental and daughter strands may result in chromatid breaks and that misreplication, because of unexcised adducts or gaps in the parental strands, may result in chromatid exchanges.

[Aortic replacement in patients with small aortic root--a modified Manouguian operation with a report in four cases].

Patch enlargement is used for aortic replacement in the cases of small aortic root. Four cases of modified Manouguian operation, a kind of patch enlargement, were presented. In this method, the splitting of aortic leaflet of mitral valve and the opening of left atrial roof were avoided. Combined with a tilting position, a No 21 artificial valve could be implanted. The method is simpler, especially in the cases of double valve replacement, in which there is no possibility to split the aortic leaflet of mitral valve. The author's experiences were introduced.

Effect of cardiopulmonary bypass on the specific immunity of the host.

T cell subsets and immunoglobulin (Ig) were observed sequentially with the OKT monoclonal antibodies rosette test and the rate scattering turbidimetry in 13 patients who underwent open heart surgery under cardiopulmonary bypass (CPB) for rheumatic heart diseases (RHD) and congenital heart diseases (CHD), before and after operation. Compared with preoperative values, in the early period after CPB, T helper cells, T helper cells to T suppressor cells ratio and IgG decreased significantly; whereas T suppressor cells increased, in RHD and CHD. The T cell subsets returned to the preoperative levels two weeks after CPB in RHD and CHD. The IgG came back to the preoperative levels two weeks after CPB in RHD and only one week after CPB in CHD.

Improved myocardial protection by antegrade perfusion in combination with coronary sinus occlusion in the presence of left anterior descending artery obstruction.

The present study was undertaken to evaluate the improved protection of antegrade aortic root perfusion combined with intermittent coronary sinus occlusion (APCSO) for the 1-hour ischemic myocardium in the presence of left anterior descending artery occlusion, 12 dogs were divided into 2 groups: anteperfusion (AP) alone (n = 6) and APCSO (n = 6). The experimental results showed that APCSO provided a better cardioplegic distribution and a lower hypothermia (15.6 degrees C versus 17.2 degrees C) in the occluded LAD region, compared with AP. After ischemia, cardiac index and left ventricular stroke index recovered excellently in APCSO (128% to 141% and 115% to 158% of preischemic values, respectively), and much worse in AP (69% to 82% and 53% to 73% of preischemic values, respectively). Our study has confirmed that APCSO is superior to AP in myocardial protection in the presence of coronary artery occlusion.

[Ureteropelvic junction obstruction presenting with abdominal pain: a analysis of fourteen cases].

During the past three and half years (Jan, 1984-Jun. 1987), 14 cases of ureteropelvic junction obstruction presented with abdominal pain were encountered in the Department of Pediatrics, Mackay Memorial Hospital. Eight cases were male and six female. Their ages ranged from 4 years old to 12 years old. The duration of abdominal pain lasted for several days in 5 cases, several months in 4, and several years in another 5 cases. The abdominal pain was usually recurrent. It occurred once every 2 to 6 months. The location of pain was predominantly in the left abdomen and the periumbilical area. Cramping was the most characteristic symptom. Besides abdominal pain, several cases also had vomiting or abdominal mass. Laboratory examination showed some cases to have microscopic hematuria and others pyuria. All were proved by renal ultrasonography to have varying degrees of hydronephrosis. Intravenous pyelography or retrograde pyelography also confirmed the diagnosis of ureteropelvic junction obstruction. In 9 of the 14 cases, surgical intervention was performed to correct abnormalities. Six cases were followed up regularly; all showed improvement, however, one developed ureteropelvic junction obstruction on the contralateral kidney one year later. The remaining five cases who did not receive surgical treatment continued to have recurrent abdominal pain.