1996年 · 第109卷第04期

OBJECTIVE To clarify some biological behaviors of Plasmodium vivax including the periodical infectivity of gametocytes for mosquitoes, the prepatent period, the incubation period, the relapse patterns and their relationship. METHODS Laboratory reared Anopheles sinensis were fed through fetal membrane on blood from patients naturally infected with vivax malaria. After feeding at different hours, the engorged mosquitoes kept in the insectarium were dissected 5-7 days later. The percentage of mosquitoes infected and the mean number of oocysts per gut were taken as criteria of the viability of the gametocytes. The healthy volunteers artificially infected by mosquito bite or quantitative inoculation of sporozoites were treated with 1.5 g chloroquine base alone before and after the first and subsequent onset of fever to detect the natural course of disease in human body. RESULTS The infection in mosquitoes can readily be divided into upward, peak, downward and non-infective period. The infectivity reached a peak at interschizogony period and fell to low level at the time when schizogony occurred. The short incubation period was frequently observed in persons bitten by 10 infected mosquitoes or 10 000 sporozoites inoculated and the long incubation period was constantly recorded in cases receiving 100 sporozoites. When one mosquito was allowed to feed on volunteers or 1 000 sporozoites were injected, the incubation period may be short or prolonged. CONCLUSIONS The 48-hour cycle in the infectivity of gametocyte for mosquitoes was demonstrated and the peak of oocyst production preceded the peak of parasitaemia by 1 to 3 days. Prompt radical treatment is extra important. Since the incubation period is variable depending on the number of sporozoites inoculated and the tropical versus temperate zone malaria is not all-inclusive, the classification of tertian malaria might be reconsidered.

OBJECTIVE To study the preventive effect of oral artemether (Art) against schistosomal infection in the field. METHODS In Minglang District of Yiyang City, Hunan Province, there is an islet with embankment type endemic area in the southern Dongting Lake region. From August to October 1994 the residents who frequently contacted the infested water were selected for study and allocated to the Art group and the control group. About one month before the preventive Art administration, all the residents understudied were examined by stool hatching technique, and then treated orally with praziquantel at a single dose of 40 mg/kg in stool egg-negative residents and 50 mg/kg in stool egg-positive ones. In the Art group, the first dose of 6 mg/kg was given at the end of August, followed by 3 repeated doses every 15 days. Placebo (starch) was given to the control group at the same time as in the Art group. The preventive efficacy was evaluated by stool examination 25-32 days after the last medication. RESULTS In the Art group, 20 out of 365 studied residents became stool positive with an infection rate of 5.5%, while in the control group, 51 out of 376 studied residents were stool positive with an infection rate of 13.6%. The egg count per gram of feces (EPG) determined by the Kato-Katz method was 122±79 in the Art group and 681±909 in the control group. Meanwhile, two cases of acute schistosomiasis were found in the control group, but none was observed in the Art group. No apparent adverse side effect was seen during the treatment with Art. CONCLUSIONS Oral Art exhibited apparent preventive effect on the residents who contacted the infested water in schistosomiasis endemic area.

OBJECTIVE To study the serotype epidemiology and patterns of antibiotic susceptibilities of salmonellae isolated in Hong Kong over an eleven-year period. METHODS The laboratory information of 22 733 strains of salmonellae isolated from diarrhea stool samples of 7 public hospitals, 5 out-patient clinics and 2 public health laboratories and reported to the Salmonella surveillance system in Hong Kong from 1983 to 1993 were analysed. RESULTS The yearly total number of isolates has remained steady, while an increasing proportion of cases occurred in the>25 years age group with a substantial decline in the<1 age group. Males were significantly more affected than females, particularly in those<15 years old.S. typhimurium and S. derby were the two most commonly isolated serotypes throughout the period. An outbreak of S. portsmouth occurred which accounted for 15.3% of total isolates in that year. S. enteritidis has doubled in the last 2 years, while S. typhi has more than halved over the 11-year period. The S. enteritidis increase was seen mostly in the>25 age groups, with those<5 years little affected. Antibiotic susceptibility tests showed the typhoid and paratyphoid bacilli remained fully antibiotic sensitive, while non-typhoid non-paratyphoid isolates showed increasing resistance to ampicillin, chloramphenicol, tetracycline, and cotrimoxazole. CONCLUSIONS Laboratory monitoring of salmonella serotypes causing diarrhea and their antibiotic susceptibilities is essential as population movements and industrial activities increase in the southern parts of China.

OBJECTIVE To assess the interrelationship between Mg2+ and K+ in preventing reperfusion arrhythmia (RA). METHODS 72 rat hearts were randomly divided into 6 equal groups, and perfused with various combinations of Mg2+ and K+ in the perfusate by Langendorff method. Each heart was subjected to coronary occlusion for 15 minutes followed by 12-minute reperfusion. The incidence of RA was recorded. The concentration of K+ and malondialdehyde (MDA) in the coronary effluent before and after reperfusion were measured with increasing concentrations of Mg2+ and fixed concentration of K+. RESULTS All forms of ventricular arrhythmias occurred after reperfusion but with decreased incidence by increasing Mg2+ and K+. When both Mg2+ and K+ were in high level, no VF appeared on reperfusion. However, when they were both in low level, 100% of hearts developed severe arrhythmia. The concentration of K+ and MDA in the coronary effluent was markedly increased compared with that before reperfusion, and the loss of K+ and malondialdehyde (MDA) decreased with increasing Mg2+. CONCLUSIONS Mg2+ may prevent or reduce the incidence of RA by maintaining the integrity of intracellular K+ and by reducing the lipid peroxide reaction.

OBJECTIVE To review the first five years of the educational and cervical cancer screening program (ECCSP) at twelve public health centers in the metropolitan area of Taipei and to measure whether the ECCSP had an impact on cancer patterns. METHODS We used data for cervical cancers diagnosed between 1986 and 1991 from all hospitals in Taipei and from the national cancer registry. During this time period, 2 158 cervical cancers were diagnosed from thirty-nine hospitals in Taipei city, of which 5% were identified after referral from the ECCSP: RESULTS The percentage of early cervical cancers, defined as stage 0 or Ia, was 70% in women referred from the ECCSP, compared with 20% for women who were not referred from the ECCSP (P<0.001). All age groupings also demonstrated this similar difference. The case-fatality rate of cervical cancer was significantly lower for ECCSP referred patients (8 of 106, 7.5%) than for non-ECCSP referred patients (401 of 2 051, 19.6%) during this study period (P<0.01). CONCLUSIONS This information suggests that the ECCSP has had a remarkable impact on the early diagnosis of cervical cancer. It is expected that a well organized screening program will be applied to a large target population from young to old adults so that the program can be effective for reducing the mortality rate of cervical cancer in Taiwan.

OBJECTIVE To evaluate the efficacy and safety of cordocentesis for prenatal diagnosis of various fetal diseases. METHODS Fetal blood sampling was performed in 30 pregnancies from gestational week 19 to 36 for various prenatal diagnoses. We used Aloka SSD-650 real-time ultrasound scanner with 3.5 mHz curvilinear transducer during the procedure. A regular 22-gauge spinal needle was used for fetal blood sampling. RESULTS Twenty-five cordocentesis were successful at the first attempt. A second attempt of cordocentesis succeeded in three cases. In the remaining two cases, intrahepatic vein sampling and cardiocentesis were employed respectively. The duration of procedure was shorter than 15 minutes in 25 cases. 1-6 ml of fetal blood was obtained from each case. Fetal blood was diluted with amniotic fluid in four samples. Maternal blood contamination never happened. No lethal complication occurred in our series. CONCLUSIONS It is believed that cordocentesis is a safe and useful method for prenatal diagnosis, and intrahepatic vein sampling is an alternative choice when cordocentesis has failed.

OBJECTIVE To evaluate the significance of PML-RARα transcripts in patients with acute promyelocytic leukemia (APL) during remission period and to follow up the patients through monitoring aberrant gene expression. METHODS This study included 17 patients with APL (5 females and 12 males). Another 19 APL patients during relapse served as control. RNA extraction was obtained through the single-step method. By means of reverse transcriptase polymerase chain reaction (PCR), the PML-RARα was detected in the sample mRNA. RESULTS Nine out of 10 patients with complete remission (CR) duration shorter than 3 years were positive. Four cases became negative and three remained positive among 7 cases in a long remission of over 3 years. The difference of the positive rate of PML-RARα transcripts between the 2 groups was significant (P<0.05). Four among 12 positive cases relapsed. No evidence of relapse was present in the 5 negative patients after 9.6±3.9-month follow-up. Further treatment was therefore given to the 4 positive patients whose treatment was already ceased at that time. By this management they were all in CR during the following 10-month observation. CONCLUSIONS RT-PCR detection for PML-RARα transcripts was useful in monitoring MRD and guiding further treatment to obtain a long remission. Persistently positive transcripts were closely associated with the relapse.

OBJECTIVE To investigate the relationship between methylation status of M-bcr gene and transformation of chronic myelocytic leukemia (CML) from chronic to blastic phase. MATERIAL AND METHODS The methylation patterns of M-bcr in 23 patients with Ph' positive CML were studied. DNAs extracted from mononuclear cells of both chronic and blastic phases (20 cases) or blastic phases only (3 cases), were doubly digested with restriction enzymes HpaII and BglII, hybridized with a 5'M-bcr probe labeled with 32p-deoxycytidine triphosphate, and autoradiographed. RESULTS In all the patients with myeloblastic crisis, DNAs from both chronic and blastic cells of each patient showed identical methylation patterns. There was substantial heterogeneity in methylation patterns in the patients with lymphoblastic crisis. All the lymphoblastic patterns were distinct from the chronic patterns as well as the patterns shown in myeloblastic crisis. Moreover, in four out of six patients with lymphoblastic crisis, the chronic patterns were different from those in cases with myeloblastic crisis. CONCLUSIONS The methylation status of M-bcr was stable during evolution of CML from chronic to myeloblastic phase. Analysis of M-bcr methylation status may be of clinical use in distinguishing lymphoblastic from myeloblastic crisis and predicting the cell lineage of crisis when the disease is still in its chronic phase.

OBJECTIVE To explore more effective and less toxic conditioning regimen without total body irradiation for autologous bone marrow transplantation (ABMT) for acute leukemia (AL). METHODS Twenty patients with AL were treated with ABMT, including 13 cases of acute myelocytic leukemia (AML) and 7 cases of acute lymphocytic leukemia (ALL). A median of 1.06 (range, 0.69-1.75)×108 nucleated BM cells/kg was harvested and stored in normal salt solution containing heparin at 4 degrees C. The conditioning regimen (MAC) consisted of high-dose melphalan (M, 140-160 mg/m2), cyclophosphamide (CY, 120 mg/kg) and cytosine arabinoside (Ara-C, 2.0 g/m2). These 3 drugs were administered within 25 hours and the unpurged autologous marrow infusion began after another 24-hour interval. RESULTS MAC regimen could result in myeloblastic efficacy in a week. All marrow cells were reinfused within 56 hours after the harvest so that hemopoietic reconstitutions could occur in all the patients. The median time to reach a neutrophil count of>1.0×109/L and a platelet count of>50×109/L was 20 and 26 days respectively. With a median observation period of 25 months, the median duration on continuous complete remission in our patients was 22 months, and the longest reached 56 months. The median survival was 33 months, and the longest was over 6 years. The event-free survival at 2 years had reached 72%. In seven patients with leukemic relapse, six (86%) relapsed within 8 months after ABMT. The relapse rate and mortality in AML patients were significantly lower than those in ALL patients. In 7 patients with M3, relapse had not yet been observed. The nonhematologic toxic effects of MAC conditioning regimen occurred mainly in the gastrointestinal tract. CONCLUSIONS The preliminary results indicated that the ABMT using MAC conditioning regimen had some advantages in stronger antileukemic efficacy, less extrahematologic toxicity and earlier recovery of platelet and could greatly prolong the duration of remission and survival in some patients with AL.

OBJECTIVE To establish the normal values of blink reflex (BR) in healthy subjects and investigate the manifestations of BR in patients with peripheral facial paralysis (PFP). METHODS BR was investigated in 23 patients with PFP and 50 healthy persons serving as control. While stimulating the supraorbital nerve on one side, the reflex responses of bilateral inferior-orbicularis oculi were recorded respectively, in which the two components recorded on the ipsilateral side of stimulation were named R1, R2 and the contralateral one, R2'. RESULTS There was no significant difference between sexes, sides and among various groups of age R1, R2 and R2'. The mean latency of R1 was 10 msec and R2, R2', 29 msec. The absolute values of the amplitude were of relatively smaller significance due to their great variance, whereas the amplitude ratio between two sides was of some value. All patients showed absent response, delayed latency or/and abnormal amplitude on the paretic side, regardless of the side of stimulation, indicating a typically efferent involvement. CONCLUSIONS BR is another objective and noninvasive test for facial paralysis in evaluating the lesion site, scope and the abnormality degree, and predicting the prognosis if combined with the clinical conditions.

The prevalence of parasitic infectious, which are generally associated with warm climates, rurality, poverty and ignorance, has been one of the predominant problems of public health. With the commitment of the Government and the progress of modern sciences, national control programs were established in the early 1950s, but for only four diseases most hazardous to humans, i.e. schistosomiasis, malaria, filariasis and visceral leishmaniasis (kala azar) due to the limitation of financial and technical resources.