[Genetic characterization of varicella-zoster virus in people aged 20 years and under in Yichang City of Hubei Province, 2019-2020]

Objective: To analyze the genetic characteristics of varicella-zoster virus (VZV) in people aged 20 years and under in Yichang City of Hubei Province from 2019 to 2020. Methods: Based on the Yichang Health Big Data Platform, we investigated cases 20 and under clinically diagnosed as herpes zoster in three hospitals from March 2019 to September 2020. Collecting vesicle fluid and throat swab samples of the cases and completing questionnaires to obtain basic information. Real-time fluorescent quantitative PCR was used for positive identification of the virus. PCR amplification of VZV's open reading frame (ORF) and sequencing of the products to determine the VZV genotype. Analyze mutations at some specific single nucleotide polymorphism (SNP) sites. Results: Among 46 cases of herpes zoster, the male to female ratio was 1.3∶1 (26∶20) and the age ranged from 7 to 20 years old. Fifteen cases had been vaccinated against varicella, including 13 and 2 cases of 1 and 2 doses, respectively. VZV strains were detected in 34 samples (73.91%), all belonging to Clade 2. Phylogenetic tree analysis of the nucleotide of ORF22 showed, compared with Clade 2 referenced strains, the sequence matching degree of nucleotide for all 34 samples was 99.0% to 100.0%. Conclusion: The main VZV strain causing herpes zoster in people aged 20 years and under in Yichang from 2019 to 2020 was Clade 2.

[Research progress on drug resistance of anti-varicella-zoster virus drugs]

Varicella-zoster virus (VZV) causes chickenpox when it first infects humans, and the virus may reactivate in adulthood and cause herpes zoster (HZ). Broad-spectrum antiviral drugs are one of the treatments for varicella and herpes zoster, but the emergence of drug resistance poses many challenges to this treatment and increases the burden of disease on patients. This paper discusses the resistance mechanisms, resistance sites and resistance detection methods of anti-VZV drugs in order to help further research on new anti-VZV targets, new drugs and monitoring of resistance to existing drugs.

[Clinical research progress of human respiratory syncytial virus vaccine]

Human respiratory syncytial virus (HRSV) is one of the main pathogen causing severe acute lower respiratory tract infections in infants and the elderly, with high incidence rate and mortality worldwide. Vaccine is one of the important measure to prevent infection, transmission and severe disease of HRSV, but currently there is no officially approved preventive vaccine for prevention of HRSV in the world. This paper reviews and analyzes the current research and development progress of HRSV vaccine, summarizes the design routes of different types of HRSV preventive vaccines, and discusses the difficulties and challenges in vaccine research and development, in order to provide reference for the research and development of HRSV vaccine and the development of clinical trials.

[Research progress on the burden of respiratory syncytial virus infection in the elderly]

Human Respiratory Syncytial Virus (HRSV) is a serious threat to the population health. The elderly are one of the susceptible populations. The prevalence of HRSV in the elderly is generally higher than that in other age groups except children, which has gradually attracted attention in recent years. This paper reviewed the prevalence, common complications and major complications of HRSV in the elderly, briefly expounded the economic burden of HRSV infection, and proposed that attention should be paid to the disease burden of the elderly after HRSV infection, timely treat common complications, so as to reduce the occurrence of adverse survival outcomes and provide scientific evidence for the prevention and control of HRSV infection in the elderly.

[Characterization analysis of gM, gL genes of varicella zoster virus in six provinces of China]

Objective: To analyze the genetic characterization of glycoprotein M(gM.),glycoprotein L(gL) of varicella zoster virus. Methods: According to the program of "Ministry of Science and Technology of China" , Based on the 12 suspected VZV patients monitored in Beijing (1 case), Shanghai (5 cases), Jilin (2 cases), Qinghai (1 case), Guangdong (2 case) and Sichuan (case) in 2007-2015. A total of 12 Vesicle fluid and throat swab samples were collected. Positive samples were identified by Agarose gel electrophoresis and two glycoprotein genes were amplified by polymerase chain reaction (PCR). Nucleotide sequences were determined and analyzed by PCR amplification of VZV positive specimens V-OKA-BK of the domestic varicella attenuated live vaccine and the Varilrix-1 of the imported attenuated live vaccine. Nucleotide sequences of VZV positive specimens, vaccine strains (V-OKA-BK, varilrix-1) and GenBank foreign wild strains (41 strains), parent strains (P-oka), vaccine strains (V-oka, Varilrix, Varivax) were compared using BioEdit and MEGA 5.0. Results: 12 specimens were VZV positive. Compared with the vaccine strains and the parent strains, the GM gene of 1 positive specimen had radical mutation at 86686 sites, which resulted in amino acid mutation, 5 positive specimens had base mutation at 87844 sites, and 30 strains of foreign wild strains had the same variation at 87 844 sites. 1 positive specimens of gL gene in 101245 sites had base mutation, and led to amino acid mutation, 6 positive specimens at 101624, 101625, 101626 sites had base of loss and the foreign wild strains in these 3 sites had the same variation. Compared with the vaccine strains, the nucleotide and amino acid homology of gM of 12 VZV positive specimens were 99.2%-100% and 98.2%-100%, respectively, and gL of those were 99.3%-100% and 98.6%-100%, respectively. Compared with 41 strains of foreign wild strains, homology of gM's nucleotides and amino acid were 99.3%-100% and 98.5%-100%, respectively; 99.1%-100% and 98.6%-100% for gL. The results of phylogenetic analysis showed that 7 VZV positive samples were on the same branch with 4 vaccine strains and p-oka strain. Based on gL, 12 VZV positive samples were on the same branch as the vaccine strains and p-oka strain. Conclusion: This study demonstrates that the genes of gM, gL are highly conserved and remain stable immunogen, which may be involved in the attenuation of VZV and need to be further researched.

[Genetic characterization of varicella zoster virus in Jilin province in 2014, China]

OBJECTIVE

To clarify the genotype of wild-type strains of varicella zoster virus (VZV) in Jilin province in 2014, and to discriminate between v-Oka vaccine strains and wild-type strains.

METHODS

Vesicle fluid and throat swab samples were collected from 13 individuals with suspected VZV in Jilin province from January to December 2014. Viral DNA was extracted, the fragments of 15 open reading fragments (ORFs) were amplified by polymerase chain reaction (PCR), and viral genotypes were determined by single nucleotide polymorphisms (SNP). PCR restriction fragment length polymorphism (RFLP) was used to distinguish between wild-type strains and v-Oka vaccine strains. The results were analyzed with MEGA5 software, using the VZV reference strain sequences from GenBank.

RESULTS

The 13 suspected samples included 5 males and 8 females, aged 11-27 years (mean: (16.69±5.48) years). Sampling was performed on days 0 to 3 of suspected infection. VZV strains were detected in 8 samples, all belonging to Clade 2. There was a synonymous mutation (T>C) in SNP18082 compared with the v-Oka vaccine strain. Analysis of PCR-RFLPs showed that all 8 positive samples were wild-type strains (PstⅠ(+)BglⅠ(+)SmaⅠ(-)).

CONCLUSIONS

The study revealed that the VZV strains circulating in Jilin province in 2014 were wild-type strains belonging to Clade 2.

Simultaneous effects of surface spins: rarely large coercivity, high remanence magnetization and jumps in the hysteresis loops observed in CoFe2O4 nanoparticles

Well-dispersed uniform cobalt ferrite nanoparticles were synthesized by thermal decomposition of a metal-organic salt in organic solvent with a high boiling point. Some of the nanoparticles were diluted in a SiO2 matrix and then the undiluted and diluted samples were characterized and their magnetic behavior explored. The undiluted and diluted samples exhibited maximum coercivity Hc of 23,817 and 15,056 Oe at 10 K, respectively, which are the highest values reported to date, and the corresponding ratios of remanence (Mr) to saturation (Ms) magnetization (Mr/Ms) were as high as 0.85 and 0.76, respectively. Interestingly, the magnetic properties of the samples changed at 200 K, which was observed in magnetic hysteresis M(H) loops and zero-field cooling curves as well as the temperature dependence of Hc, Mr/Ms, anisotropy, dipolar field, and the magnetic grain size. Below 200 K, both samples have large effective anisotropy, which arises from the surface spins, resulting in large Hc and Mr/Ms. Above 200 K, the effective anisotropy decreases because there is no contribution from surface spins, while the dipolar interaction increases, resulting in small Hc and Mr/Ms. Our results indicate that strong anisotropy and weak dipolar interaction tend to increase Hc and Mr/Ms, and also clarify that the jumps around H = 0 in M(H) loops can be attributed to the reorientation of surface spins. This work exposes the underlying mechanism in nanoscale magnetic systems, which should lead to improved magnetic performance.

c-Met and RON expression levels in endometrial adenocarcinoma tissue and their relationship with prognosis

OBJECTIVE

To investigate the potential relevance of c-Met and RON gene expression in patients with adenocarcinoma of the endometrium and analyze the relationships among the c-Met and RON expression, clinicopathological characteristics, and patient survival.

MATERIALS AND METHODS

The study included 60 cases diagnosed with endometrial adenocarcinoma with more than five-years follow-up. Total RNA from formalin-fixed paraffin-embedded tissues of 60 adenocarcinomas of the endometrium and normal endometrium tissues were isolated for c-Met and RON quantitative analysis by real-time real-time polymerase chain reaction (RT-PCR).

RESULTS

The c-Met and RON expression in endometrial adenocarcinoma was significantly higher than that in normal endometrial tissues (p < 0.01), with average up-regulated levels of 3.94 ± 1.88 and 2.74 ± 0.88, respectively. Moreover, high c-Met expression was significantly correlated with the histological stage (p = 0.017), and high RON expression was related to histological stage (p = 0.035), muscle invasion (p = 0.006), and lymph node metastasis (p = 0.018). Multivariate Cox regression analysis revealed that the co-expression of c-Met and RON was an independent prognostic factor for adenocarcinoma of the endometrium and was significantly associated with decreased overall survival (HR = 3.571, p = 0.014).

CONCLUSION

The co-expression of c-Met and RON is associated with a poor prognosis in endometrial adenocarcinoma and is an independent prognostic marker for endometrioid adenocarcinoma.

The relationship between solitary pulmonary nodules and bronchi: multi-slice CT-pathological correlation

AIM

To investigate the relationship between solitary pulmonary nodules (SPN) and bronchi and its value in predicting the nature of the SPN.

MATERIALS AND METHODS

We performed volumetric targeted scans of 0.5 mm collimation with multi-slice computed tomography (MSCT), reconstructing multiplanar reconstructions (MPR), curved multiplanar reconstructions (CMPR) and surface-shaded display (SSD) images of bronchi in 78 consecutive patients with SPN (53 malignant and 25 benign) and correlated the findings with those of macroscopic and microscopic specimens.

RESULTS

With this CT protocol, the third to seventh-order bronchi were shown continuously and very clearly in all patients. CT findings were consistent with those of specimens. CT demonstrated the relationship between the SPN and bronchi in 46 (86.8%) malignant and 18 (75.0%) benign nodules. Five types of tumour-bronchus relationships were identified with MSCT. Type I: the bronchus was obstructed abruptly by the SPN; type II: the bronchus penetrated into the SPN with tapered narrowing and interruption; type III: the bronchial lumen shown within the SPN was patent and intact; type IV: the bronchus ran around the periphery of the SPN with intact lumen; type V: the bronchus was displaced, compressed and narrowed by the SPN. Malignant nodules were most commonly of type I (58.5%), secondly of type IV (26.4%) and rarely of type V (1.9%). Benign nodules were most often of type V (36.0%), followed by type III (20.0%), type I (16.0%), and there were no type II. Types I, II and IV were more common in malignant nodules, whereas type V was seen more frequently seen in benign nodules (p<0.05). There was no statistically significant difference between the two groups regarding type III.

CONCLUSION

Ultra-thin section with MSCT and MPR, CMPR and SSD reconstruction can improve the demonstration of the patterns of tumour-bronchus relationships, which can reflect the pathological changes of the nodules to some extent and help differentiate malignant from benign tumours.

[Changes of synaptic transmission efficiency in the MF-CA3 and PP-CA3 pathways of rat hippocampus during discrimination learning]

Electrophysiological and behavioral studies were performed in rat to investigate the changes of synaptic efficacy of the two inputs of hippocampal CA3 area [Mossy Fiber (MF) -CA3 and Perforant Path (PP) -CA3] during discrimination learning. The results showed that: (1) Amplitude of the population spike (PS) of both from MF-CA3 and PP-CA3 increased simultaneously with the establishment of conditioned response (CR) and both reached their maxima before CR reached the criterion of acquisition. (2) During natural extinction of CR, the amplitude of PS of both inputs decreased also simultaneously to their per-training level. These results indicated that the learning-dependent long-term potentiation (LTP) in both MF-CA3 and PP-CA3 inputs developed and extinguished synchronously, suggesting that the changes of synaptic efficacy of different inputs of hippocampal CA3 area coordinated during discrimination learning.

[The histological change, MRI manifestation and neurological deficiency of old spinal cord injury]

The L1 spinal cord of 22 dogs were injured by modified Allen's method. During the interval of 50-100 days after injury, MR imaging were performed and the specimens of the injured spinal cord were taken out immediately for histological examination. T1 weighted images were used to observe changes of spinal cord signals. In 7 cases with cavity formation in the central part of the injured spinal cord was found histologically, there was small cavity in the spinal cord signal on MRI. In 12 cases with necrosis and softening in central area of the spinal cord, the T1 weighted image showed hypointensity in central part of spinal cord signal, and in 3 cases with necrosis, degeneration and glial replacement histologically, the MR image showed unhomogeneous and slight hyointensity signal. These entities suggested that the MRI appearances of spinal cord injury represented the histological changes of the spinal cord. Clinically, the MRI manifestation of 76 cases of old spinal cord injury were closely related to their neurologic deficiency. Cases of transection signal of spinal cord were excluded. There were six types of MRI appearances. In 40 cases of complete paraplegia, the MRI appearances were enlarged hypointensity signal in 16 hypointensity signal in 4, atrophy of the spinal cord in 13, large cavity in 3 and unhomogeneous with compression in 1. After treatment, there were no recovery in all cases. 36 cases of incomplete paraplegia their MRI showed normal signal but compressed in 16, all had good recovery after treatment. Unhomogenous signal with slight hypointensity was found in 11, they one frankle degree recovery after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of 6-OHDA lesions of the bilateral dorsal noradrenergic bundle on learning-dependent long-term synaptic potentiation in dentate gyrus]

In the present study, the role of NE in learning-dependent long-term potentiation (LdLTP) was investigated by examining the effects of 6-hydroxydopamine (6-OHDA) lesion made in the bilateral dorsal noradrenergic bundle on the changes of synaptic efficacy in dentate gyrus (DG) and related conditioned response during drinking conditioning. Bilateral injection of 6-OHDA (12 micrograms/4 microliters) into the dorsal noradrenergic bundle caused a continuous decrease of the amplitude of population spike (PS) reaching a value of 50 +/- 6.3% and 28 +/- 6.4% respectively at the 6th and the 12th day after injection of the drug. During this period of 7 days, the LdLTP could not be produced in spite of 20 trainings per day for a total of 140 trials, and the conditioned drinking response could not be established. The above results indicate that normal levels of norepinephrine in the hippocampus are necessary to the establishment of LdLTP in the DG and suggest that the development of LdLTP in the DG may be modulated by the nucleus locus ceruleus via the dorsal noradrenergic bundle.

[Role of N-methyl-D-aspartate receptor in the maintenance of learning-dependent long-term potentiation in rat hippocampal CA3 area]

The effect of microinjection of 2-amino-5-phosphonovaleric acid (APV), a selective NMDA receptor antagonist, into the rat hippocampal CA3 area on the synaptic efficacy and related conditioned behavior during the acquisition and consolidation of discrimination learning behavior was examined. The results showed: (1) After population spike (PS) amplitude had just increased to the maximum through training i.e. learning-dependent LTP had just formed, APV 1 microliter (2 mmol/L) was injected into CA3 area, then the rats were trained during the time of efficacy of the drug in every experimental block. The result demonstrated that the PS amplitude could not be maintained at the highest level but decreased to the pre-experiment level after 8 blocks. Correct response percentage of rats could not be consolidated with further training but decreased to less than 10%. (2) After the PS amplitude had kept up at the highest level, APV 1 microliter (2 mmol/L) was injected into CA3 area, then the rats were trained during the time of efficacy of the drug in every experimental block, in which case the PS amplitude also could not be maintained at the highest level but decreased to the pre-experiment level after 14 blocks. Correlatively, when the correct response percentage of rats decreased gradually to less than 10%, the conditioned response of the animals extinguished, but its extinction speed was slower than it was in result (1). These results suggest that the NMDA receptor in CA3 area plays an important role in the maintenance of the learning-dependent long-term potentiation.

[Percalcar Steinmann's pins fixation of intratrochaner fixation fracture. Clinical observation]

80 cases of intratrochaner fractures were treated by fixation of 4 Steinmann's pins which were 3.5 mm in diameter and inserted percutaneously through the calcar and compression trabeculae and distension trabeculae respectively. They were compared with the cases treated by skeletal traction or fixed by Nail-plate or angle plate. The rate of bony union in fixed position in the percalcar Steinmann's pins group was 83.7%. Normal neck-shaft angle accounted to 53.1% in the traction group. Varus deformity occurred in 16.3% cases of the Steinmann's pins group, and 35.9% cases of the traction group. The deformity was most frequently seen in cases of type IIIa and IV. No fixation failure occurred in the Steinmann's pins group. The Steinmann's pins passing through the outer cortex, calcar and compression trabeculae produced strong fixation and it's direction was in parallel to the weight-bearing line of the hip, with less shearing force and much compression force distributed on the fracture line. The operation was done under local anesthesia. No blood transfusion and early mobilization were the advantages of this method.

[Diagnostic value of magnetic resonance imaging for chronic injury of spine and spinal cord]

From March 1989 to July 1990, Magnetic resonance imaging (MRI) examination was conducted in 60 patients with chronic injuries of the spine and the spinal cord, of whom 32 patients received exploration and decompression operation. Based on the results of MRI, clinical neurological examinations, biological electrical examinations were compared treatment. MRI proved to show the minute changes of the spine, the definite location of spinal compression, the narrowing of spinal canal and the actual cause of compression objects. Thus, it is helpful in selecting treatment and in predicting prognosis.

[Internal fixation for intertrochanteric fracture. Biomechanical study]

A Type IIIa intertrochanteric fracture was made on the preserved femurs of adult cadavers. The fracture was fixed by 4 methods: Percalcar Steinmann's pins, Knowle's pins, Nail plate and Angle plate. The loading limit of the fixations were 150, 140, 70 and 40 kg respectively. In fatigue test the loading ability of the percalcar Steinmann's pins were 4 times greater than that of Nail plate or Angle plate. In Nail plate and Angle plate. The pathological section of the upper femur showed the most bony destruction was at the trabecula beneath the lateral cortex, and in the percalcar Steinmann's, it was at the neck trabecula, where the cal car plays an important role in supporting the loading of the lowest pin. It was found that the level arm was shortened and the loading ability increased. As the direction of the lowest pin was nearly parallel to the loading axis of the hip. The calcar suffered less shearing force. These findings showed that the percalcar Steinmann's pins fixation is the best in these 4 methods.

[Effect of scopolamine and picrotoxin on the learning-dependent long-term synaptic potentiation]

The purpose of this study was to investigate the effects of microinjection of scopolamine, a M-cholinergic antagonist and picrotoxin, a GABA-ergic antagonist into the rat hippocampal CA3 area on the learning-dependent long-term potentiation (LDLTP) during the establishment, extinction and re-establishment of conditioned drinking response. Following stimulation of the perforant path, field potentials of hippocampal CA3 of freely moving rats were recorded. The results were as follows: the synaptic efficacy and the development of LDLTP in hippocampal CA3 were depressed significantly by scopolamine, but the extinction of LDLTP was accelerated. Picrotoxin significantly enhanced synaptic efficacy and facilitated the development of LDLTP, but it depressed the extinction of LDLTP. Meanwhile, the establishment or extinction of drinking conditioning was correspondingly depressed or accelerated. Moreover, the development of LDLTP and its extinction preceded the development and extinction of drinking conditioning. The results provide further evidence indicating that LDLTP might be one of the neuronal mechanisms underlying behavioral learning and memory. Moreover, it seems that M-cholinergic receptors and GABA-ergic receptors in rat hippocampal CA3 area are involved in the development and retention of LDLTP.

[Effect of electroshock on learning-dependent long-term potentiation in rat hippocampal CA3 area]

Population spikes were recorded from hippocampal CA3 of freely moving rats following stimulation of the perforant path. Six rats were trained to perform conditioned drinking behavior. (1) Animals were treated with electroshock in less than 15 minutes after daily training session for a period of 6 consecutive days. Synaptic efficacy did not increase and the conditioned response could not be established during the behavioral training in four rats, synaptic efficacy was increased, the long-term potentiation (LTP) appeared and the conditioned behavior was established in other two rats. (2) After consolidation of conditioned behavior, electroshock temporarily caused suppression of the learning-dependent LTP and the correlative conditioned response. Both LTP and the correlative conditioned response recovered in one to four hours after electroshock. In these cases, the maximal development of LTP preceded the development of conditioned behavior. The results indicated that the learning-dependent LTP might be one of the neural substrates underlying learning and memory.

[The learning dependent long-term synaptic potentiation in the rat hippocampal CA3 region]

The purpose of this study is to investigate the changes of synaptic efficacy in the rat hippocampal CA3 region during establishment, extinction and re-establishment of conditioned drink response by means of implanted electrodes and behavioral observation. The monosynaptic population excitatory postsynaptic potential (EPSPs) and population spike (PS) elicited by stimulating the perforant path were recorded. The results showed that the long-term potentiation (LTP) in the hippocampal CA3 region appeared with the establishment of conditioned response, the LTP extinguished with experimental extinction of conditioned response and reappeared during the re-establishment of conditioned response. Moreover, both maximal level of LTP and its complete extinction preceded those of conditioned behavior, suggesting that the LTP was learning-dependent. In addition, the enhanced PS was not presented immediately after behavioral training, and developed within subsequent 24 h, with a maximum at the 4th hour. The magnitude of conditioned response depended on the level of LTP. A cross-correlation analysis of the slopes of PS and EPSPs indicated that the changes of PS were caused by alterations of synaptic transmission. These results suggest that the learning-dependent LTP might be one of the neuronal substrates underlying behavioral learning and memory.

[Vertebrectomy in treating fracture-dislocation of the spine with paraplegia]

From April 1980 to August 1984, 11 cases of fracture--dislocation of spine at the level of T-11 to L-2 with obvious kyphosis at the site of displacement, with paraplegia, were treated by vertebrectomy through posterior median approach. The operations were performed 2 to 28 weeks, averaging 8 weeks, after injury. 5 of the 9 patients who had complete paraplegia suffered also causalgia in both legs. The other 2 had incomplete paraplegia only. Follow-up study, 4 years and 5 months post-operation on average, revealed complete reduction of the fracture-dislocation in 10 patients and incomplete in one, getting solid bony union in all. Concerning the neurological findings of the 9 complete paraplegic patients, 5, who had suffered from causalgia got varying degree of relief, 5 regained sensation of pain in region 2 segments lower, of the 2 incomplete paraplegic patients, 1 regained sensation of pain in both legs and muscular power of degree 4 in both thighs, so that walking became possible, while the another one fell into complete paraplegia, because of compression of the cord at T-10 happened during operation and showed no signs of recovery afterward.

Vaccination of bovines against schistosomiasis japonica with highly irradiated schistosomula in China

Vaccination of Chinese bovines (cattle and buffaloes) against schistosomiasis japonica with 36 kR gamma-irradiated schistosomula was done for laboratory challenge and for field trials in China. Altogether, 61 bovines were used. All experimental animals were vaccinated 2-3 times with 10,000 irradiated schistosomula per time. For the laboratory challenge, all experimental and control cattle were challenged with 500 normal cercariae and each buffalo, with 2,000 cercariae. The laboratory-challenged bovines were killed after 54-57 days of challenge; the bovines for the field trial in the lightly endemic area, after 5 months in the field; and the bovines for the field trial in the heavily endemic area, after 58-63 days. When the animals were killed, the number of mature worms in the vaccinated (experimental) and non-vaccinated (control) animals was recorded and the percentage of worm reduction in each group was calculated. The first group, consisting of three vaccinated and three non-vaccinated cattle, was given a laboratory challenge; the worm reduction was 71.6%. The second group, consisting of two vaccinated and three non-vaccinated buffaloes, was also given a laboratory challenge; the worm reduction was 74.4%. The third group, consisting of seven vaccinated and eight non-vaccinated buffaloes, was utilized in a field trial in a lightly endemic area; the worm reduction was 75.6%. The fourth group, consisting of eight vaccinated and nine non-vaccinated cattle, and the fifth group, consisting of nine vaccinated and nine non-vaccinated buffaloes, were pastured in a heavily endemic area. The worm reduction was 65.1% in the fourth group and 75.7% in the fifth group.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunization of mice with ultraviolet-irradiated Schistosoma mansoni cercariae: a re-evaluation

Mice immunized by percutaneous exposure to ultraviolet-irradiated Schistosoma mansoni cercariae developed levels of resistance to subsequent S. mansoni infection comparable to those induced by gamma-irradiated cercariae (50-70% reduction in adult worm burden). Cercariae treated with ultraviolet doses ranging from one to three times the minimum dose required to prevent long-term survival induced the highest levels of resistance.

Vaccination against bovine schistosomiasis japonica with highly X-irradiated schistosomula

Cercariae of the Chinese mainland strain of Schistosoma japonicum were used. Eighteen cattle, divided into six groups of three each, were immunized with schistosomula transformed from cercariae exposed to three different doses of X-irradiation (24, 36, and 48 kR). The immunization was given either once, twice, or thrice, and the number of immunizing schistosomula was 10,000 or more in each immunization. The immunized cattle were challenged with 500 normal cercariae. Five native cattle were similarly infected with normal cercariae as controls. All cattle were killed 32-33 days after challenge or infection, and the worms were obtained by perfusion. The mean worm reduction in the 18 experimental animals varied from 42.1 to 96.0%. The mean percent worm reduction of the six experimental groups varied from 54.8 to 87.1. The reduction was greater with increasing numbers of immunizations, and was higher in the groups immunized with schistosomula exposed to 36 kR than in those exposed to 24 or 48 kR. Statistical analyses showed that all immunized groups yielded significantly fewer worms than controls. However, the three doses of X-irradiation (24, 36, and 48 kR) had no significant effect for a fixed number of immunizations (1, 2, or 3). The means for both two and three immunizations were significantly different from the mean for one immunization, although they were not significantly different from each other.

Histopathological study of the attrition of challenge cercariae of Schistosoma mansoni in the skin of mice immunized by chronic infection and by use of highly X-irradiated cercariae

To find direct evidence for the sites of death of newly transformed schistosomula of Schistosoma mansoni in the skin of challenged immunized hosts, a histopathological study of the skin of chronically infected mice and of highly X-irradiated cercaria-immunized mice was made at different post-challenge times. Attrition of infecting organisms in naive mice was used as a control. In general, three main kinds of schistosomular attrition were observed: (1) in the granulocytic exudates in the epidermis, (2) in the granulocytic aggregates in the subcutaneous tissue, and (3) in the granuloma-like foci in the subcutaneous tissue. Schistosomula killed by the epidermal granulocytic exudates and by the subcutaneous granuloma-like foci occurred in all three groups of mice, but the schistosomula killed by the subcutaneous granulocytic aggregates were found only in the highly X-irradiated cercaria-immunized animals. Schistosomula killed by the epidermal granulocytic exudates were encountered occasionally in the challenged naive mice but more frequently in both the challenged chronically infected mice and the challenged highly X-irradiated cercaria-immunized mice. The number of subcutaneous granuloma-like foci was greater in the challenged mice immunized with highly X-irradiated cercariae than in the challenged naive mice or the challenged chronically infected mice. Another differentiating character among the three groups of mice was that in the highly X-irradiated cercaria-immunized group, the subcutaneous granuloma-like foci appeared on day 3 after the challenge, but on day 5 in the naive and chronically infected groups. The results clearly indicate that skin is an important site for the attrition of the challenged cercariae in the highly X-irradiated cercaria-immunized mice, and that immunity in the chronically infected and X-irradiated cercaria-immunized mice occurs by different mechanisms.