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21.
Plasmid DNA vectors have been constructed with minigenes encoding a single cytotoxic T lymphocyte (CTL) epitope from either the M2 protein of respiratory syncytial virus (RSV) or from the nucleoprotein of measles virus (MV) with or without a signal sequence (also called secretory or leader sequence). Following intradermal immunization, plasmids in which the CTL epitopes were expressed in-frame with the signal sequence were more effective at inducing peptide- and virus- specific CTL responses than plasmids expressing CTL epitopes without the signal sequence. This immunization resulted in protection against MV-induced encephalitis and a significant reduction in viral load following RSV challenge. The reduction of viral load following RSV challenge was abrogated by prior injection with anti-IFN-gamma antibodies. These results highlight the ability of epitope-based DNA immunization to induce protective immune responses to well-defined epitopes and indicate the potential of this approach for the development of vaccines against infectious diseases.   相似文献   
22.
Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.   相似文献   
23.
Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.  相似文献   
24.
25.
A reliable, sensitive and specific sandwich ELISA for the quantitation of paired helical filament (PHF) tau in human brain was developed using well-defined monoclonal antibodies. We examined rapid-autopsy-derived brain tissue from 21 neuropathologically confirmed Alzheimer's disease (AD) patients and 14 nondemented controls, matched for age, sex and postmortem delay times. We demonstrated significant elevations of phosphorylated tau levels in the frontal and parietal cortex as well as in the hippocampus of AD patients as compared to the nondemented controls. No difference was observed in the cerebellum. Phosphorylated tau levels measured by ELISA were significantly correlated with the presence or absence of neurofibrillary tangles.  相似文献   
26.
When common movement is superimposed on relative movement (changes in separation between two dots), relative movement thresholds increase nonlinearly as a function of initial dot separation. For large separation (greater than 2.0 deg), thresholds increase gradually with increased separation. It is shown that this reflects judgments based on perceived relative motion. For small separations (less than 2.0 deg), thresholds increase sharply with increased separation. It is shown that this reflects judgments based on perceived changes in relative position. Evidence is presented that superimposed common movement reduces sensitivity to relative movement by reducing sensitivity to relative motion. This provides a "window", in the range of small dot separations, for relative movement judgements to be based on the perception of changes in relative position, even though motion is perceived for individual dots.  相似文献   
27.
IL Ackerman  CA Karn  SC Denne  GJ Ensing  CA Leitch 《Pediatrics》1998,102(5):1172-1177
OBJECTIVE: The purpose of this study was to determine the effect of left-to-right shunting on the resting energy expenditure (REE), total energy expenditure (TEE), and energy intake in a group of 3- to 5-month-old infants with moderate to large unrepaired ventricular septal defects (VSDs) compared with age-matched, healthy infants. METHODS: Eight infants with VSDs and 10 healthy controls between 3 to 5 months of age participated in the study. Indirect calorimetry was used to measure REE and the doubly-labeled water method was used to measure TEE and energy intake. An echocardiogram and anthropometric measurements were performed on all study participants. Daily urine samples were collected at home for 7 days. Samples were analyzed by isotope ratio mass spectrometry. Data were compared using analysis of variance. RESULTS: No significant differences were found in REE (VSD, 42.2 +/- 8.7 kcal/kg/d; control, 43.9 +/- 14.1 kcal/kg/d) or energy intake (VSD, 90.8 +/- 19.9 kcal/kg/d; control, 87.1 +/- 11.7 kcal/kg/d) between the groups. The percent total body water was significantly higher in the VSD infants and the percent fat mass was significantly lower. TEE was 40% higher in the VSD group (VSD, 87.6 +/- 10.8 kcal/kg/d; control, 61.9 +/- 10.3 kcal/kg/d). The difference between TEE and REE, reflecting the energy of activity, was 2.5 times greater in the VSD group. CONCLUSIONS: REE and energy intake are virtually identical between the two groups. Despite this, infants with VSDs have substantially higher TEE than age-matched healthy infants. The large difference between TEE and REE in VSD infants suggests a substantially elevated energy cost of physical activity in these infants. These results demonstrate that, although infants with VSDs may match the energy intake of healthy infants, they are unable to meet their increased energy demands, resulting in growth retardation.  相似文献   
28.
The Dunning H rat prostate tumor (R3327H) is a widely used experimental model of human prostatic adenocarcinoma (CaP). The Dunning H tumor has been characterized as androgen-sensitive, androgen-receptor (AR) positive, prostate-specific antigen and prostatic acid phosphatase (PAP) positive. To date, the tumor has been maintained by serial passage in vivo because of the lack of an in vitro cell line that retains the characteristics of the in vivo tumor. The objective of the present study was to establish a propagable cell line from R3327H adenocarcinoma that maintained androgen sensitivity and expression of AR, PSA and PAP. Tissue harvested from an in vivo R3327H tumor was dissociated with collagenase and placed into Richter's improved media (with supplements). A cytokeratin-positive epithelial cell line (HUNC- E) and a vimentin-positive stromal cell line (HUNC-S) were generated from the primary culture, subcultured continuously for >300 days, and passaged >50 times. Survival of the HUNC-E cell line in vitro depended on several media supplements, including nicotinamide, insulin, transferrin, selenium and epidermal growth factor (EGF). HUNC-E cells expressed AR and produced PSA and PAP throughout the culture period, as confirmed by immunocytochemistry and Western blot analyses. Addition of 14 nM testosterone (T) or dihydrotestosterone (DHT) to HUNC-E cells, stimulated DNA synthesis as well as anchorage-independent growth and PSA production, which demonstrated the androgen-sensitive nature of the cells in vitro. When HUNC-E and HUNC-S cells were combined in a 3:1 ratio and introduced subcutaneously into syngeneic male hosts, tumors formed in 2/3 animals with an average latency of 7 months. RT-PCR and immunocytochemical characterization of the HUNC cell lines revealed that the cells expressed several growth factors and their cognate receptors, including HGF, TGF-alpha and the TGF-betas, indicating the establishment of potential autocrine loops in the neoplastic cells. The HUNC-E and HUNC-S CaP cell lines, which retain the characteristics of the epithelial and stromal components of the in vivo R3327H tumor, will allow a more thorough and informative molecular and biological analysis of prostatic adenocarcinoma.   相似文献   
29.
A study was carried out to find out the effects of prior physical activity, sports participation and prior military training on the incidence of stress fractures among Gentlemen Cadets (GC''s) undergoing military training at Indian Military Academy (IMA). One thousand and fourteen GC''s were followed up for a period of 12 weeks. Thirty-seven GC''s developed stress fractures during the study period. The incidence of stress fractures was significantly higher in GC''s without any prior military training (p=0.0009). They were compared with 100 healthy controls drawn from the study population to study the influence of the other mentioned factors. There was no significant association between prior physical activity and stress fractures (OR=0.74, 95% CL=0.26 to 2.05, p=0.688). There was also no significant relationship between sports participation and stress fractures (OR=0.79. 95% CCL=0.35 to 1.81, p=0.684).KEY WORDS: Risk factors, Stress fractures  相似文献   
30.
With the increasing incidence of multifetal gestations, it is essential for the clinician to appreciate the benefit of ultrasound evaluation in these pregnancies. Multifetal gestation pregnancies are at increased risk for a range of both antepartum and intrapartum complications, such as intrauterine growth restriction, premature delivery, congenital anomalies, cord accidents, malpresentations, placenta previa, and abruptio placentae. First-trimester ultrasonic evaluation, amniotic fluid assessment, monitoring of fetal growth, diagnosing the twin-to-twin transfusion syndrome, and assessment of fetal anomalies will be reviewed. An early and accurate assessment of amnionicity and chorionicity are paramount in these gestations. The impact of chorionicity, in particular, can have profound consequences in the management of multifetal gestations. The determination of chorionicity onultrasonic evaluation in a multifetal gestations. The determination of chorionicity on ultrasonic evaluation in a multifetal pregnancy should be determined in a systematic way between 10-14 weeks' gestation. The amniotic fluid volume should be routinely assessed when performing an ultrasonic evaluation in a multifetal pregnancy. Amniotic fluid changes may serve as the only useful indicator to a potential pathological condition. In addition, evaluation of fetal growth in twins is essential, because these pregnancies are at increased risk for growth restriction and increased perinatal mortality rates compared to singletons. Finally, a careful anatomical evaluation in mulitifetal gestation is important because twin pregnancies have higher rates of anomalies than their singleton counterparts.  相似文献   
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