Ultrasonic imaging of the electroacoustic effect in macromolecular gels

The electroacoustic effect occurs in electrolytes and colloidal suspensions. It describes the phenomenon in which a voltage applied to the sample produces an acoustic signal or vice versa. The basic mechanism is that charged particles in the sample have various mobilities due to different masses and viscosities. Under an external voltage they respond differently to the electrical force. This results in an overall acoustic vibration. The electroacoustic effect has been the basis for many measurement tools of solutions and other materials. In this note a method to image macromolecular gel samples using the electroacoustic effect at ultrasound frequencies is presented. Radiofrequency electrical excitation produces ultrasonic signal due to spatial changes in the electroacoustic some amplitude of the sample, which is used to construct an image similar to ultrasonography. This method is demonstrated in agar gel and egg-white protein phantoms. The image contrast mechanism is also discussed.

The potential for Hall effect breast imaging

Hall effect imaging is a noninvasive imaging method that combines ultrasound with a strong magnetic field to investigate the electrical properties of tissue. Although technical development is at an early stage, its value for detecting or characterizing pathologies in the breast and other organs is promising. In vitro studies in the past showed that tissue electrical properties are closely related to its physiology and morphology. Hall effect imaging may become a new tool to study these electrical properties in the body and potentially provide unique diagnostic information.

Reduction of field of view in MRI using a surface-spoiling local gradient insert

Herein is presented a method for suppressing the magnetic resonance signal to a controlled depth by applying a spatially heterogeneous spoiler field between the slice-select and readout pulses. Eliminating the signal from near-surface regions allows one to shrink the field of view without introducing aliasing artifacts, thereby decreasing imaging time over a smaller defined volume. A unique planar magnetic gradient coil was constructed to generate the spoiler field. Phantom and human subject studies showed that the signal can be suppressed to controlled distances of up to 90 mm from the coil, with modest requirements on power supplies, pulse sequences, and materials, and with no increase in imaging time.

High-sensitivity fiber-optic ultrasound sensors for medical imaging applications

This paper presents several designs of high-sensitivity, compact fiber-optic ultrasound sensors that may be used for medical imaging applications. These sensors translate ultrasonic pulses into strains in single-mode optical fibers, which are measured with fiber-based laser interferometers at high precision. The sensors are simpler and less expensive to make than piezoelectric sensors, and are not susceptible to electromagnetic interference. It is possible to make focal sensors with these designs, and several schemes are discussed. Because of the minimum blending radius of optical fibers, the designs are suitable for single element sensors rather than for arrays.

Hall effect imaging

This paper presents a new imaging method based on the classical Hall effect (HE), which describes the origin of a detectable voltage from a conductive object moving in a magnetic field. HE images are formed using ultrasound imaging techniques in a magnetic field. These images reflect the electrical properties of the sample. To demonstrate the feasibility of this method, images of plastic and biological samples are collected. The contrast mechanism and signal-to-noise issues are discussed. Since electrical parameters vary widely among tissue types and pathological states, HE imaging may be a useful tool for biological research and medical diagnosis.

Small-dose itraconazole pulse therapy in the treatment of onychomycosis

The aim was to evaluate efficacy and tolerance of a short-schedule treatment regimen using a small dose of itraconazole in pulse intermittently. The open study evaluated the pulse therapy consisting of monthly 1-week cycles of oral itraconazole 200 mg daily for 2-3 consecutive months in 42 patients with onychomycosis. After active therapy, patients were evaluated for a maximum period of 1 year. Twelve of 42 patients were considered as being clinically cured, 17 were markedly improved, 11 were improved and two were failures. A mycological examination at the final visit was performed on all patients. Thirty-five were negative and seven were positive. This short treatment was well tolerated, with no adverse reactions, and may offer a new option for treatment of onychomycosis.

Centric ordering is superior to gradient moment nulling for motion artifact reduction in EPI

Echo-planar imaging (EPI) is sensitive to motion despite its rapid data acquisition rate. Compared with traditional imaging techniques, it is more sensitive to motion or flow in the phase-encode direction, which can cause image artifacts such as ghosting, misregistration, and loss of spatial resolution. Consequently, EPI of dynamic structures (eg, the cardiovascular system) could benefit from methods that eliminate these artifacts. In this paper, two methods of artifact reduction for motion in the phase-encode direction are evaluated. First, the k-space trajectory is evaluated by comparing centric with top-down ordered sequences. Next, velocity gradient moment nulling (GMN) of the phase-encode direction is evaluated for each trajectory. Computer simulations and experiments in flow phantoms and rabbits in vivo show that uncompensated centric ordering produces the highest image quality. This is probably due to a shorter readout duration, which reduces T2* relaxation losses and off-resonance effects, and to the linear geometry of phantoms and vessels, which can obscure centric blurring artifacts.

[Influence of processing on atractylenolide III content in Atractylodes macrocephala Koids]

The atractylenolide III content in different processed products of Atractylodes macrocephala was determined by HPLC. The result has shown that the content in the processed products appears higher than that in the crude herb, with the yellow-fried product being the highest.

Public health importance of cystic echinococcosis in China

Cystic echinococcosis has been recorded in 21 out of China's 31 provinces, autonomous regions and municipalities (approximately 87% of territory). It constitutes one of the major public health problems, especially in several northwestern provinces and autonomous regions. This paper reviews the general situation, diagnosis, treatment, education and control programmes and international cooperation. Special attention is given to the Xinjiang, an endemic area about one sixth of the country's area with a human population of approximately 16 million.

Identification by polymerase chain reaction fingerprinting of Cryptococcus neoformans serotype AD

Seventy-three Cryptococcus neoformans isolates and eight other yeast strains were studied. Fingerprints produced by priming with (GACA)4 differentiated C. neoformans from all other yeasts tested and identified the five C. neoformans serotypes. Four major bands of molecular size 800, 540, 475 and 410 bp were recognized for serotypes A, AD and D. Two of them were specific for serotype A and the other two for serotype D isolates. Serotype AD strains were identified by five different genotypic patterns in which at least one of the two bands specific for serotype A and D were present in different combinations. On repeated and simultaneously performed genotype and serotype testing of nine strains, the genotypic pattern did not change, whereas serotyping was unstable in three cases. PCR-fingerprinting using (GACA)4 as a primer proved more stable than serology in discriminating among C. neoformans serotypes A, D and AD and was able to distinguish among serotype AD strains.

[The clinical and pathological characteristics of epithelial ovarian carcinoma in patients with age under 40]

OBJECTIVE

To investigate the clinical and pathological characteristics of epithelial ovarian carcinoma in patients with age under 40.

METHODS

From Jan 1978 to Dec 1992, 54 cases with epithelial ovarian carcinoma under 40 years old were admitted to our hospital and enrolled in the study group, another 54 patients suffered from the same disease with age over 40 in the same period were served as control. Comparison analysis for clinical and pathologic data of 2 groups was performed using SPSS and SURVALC statistics software.

RESULTS

Main complaint because of either pelvic mass or abdominal mass found by chance was more common in study group (46.3%) than that in control group (27.8%). whereas because of symptoms was less common in study group (53.7%) than in control group (72.2%). Other parameters such as early stage (I and II) rate (61.1%), unilateral tumor rate (68.5%), average maximum diameter of tumor (13.6 cm), highly differentiated rate (50%) and the possibility for tumor reductive surgery were higher in study group than in control group. The difference of histological pattern and chemotherapy between 2 groups was not significant. Single variate analysis showed that the prognosis was better in study group. The 2-year and 5-year survival rates were 69.8% and 50.2% respectively. No recurrence was found in the 8 patients in whom the contralateral healthy ovary remained. However multiple variate analysis indicated that age was not a prognostic factor.

CONCLUSION

Epithelial ovarian carcinoma was prone to be lower degree malignancy in patients under 40 years therefore the prognosis of them was better. It might be resonable to have healthy ovary left in some select cases.

[Determination on the glycosyl sequence of gypenoside A by TLC-FABMS]

The glycosyl sequence of gypenoside A (A) isolated from Gynostemma pentaphyllum Makino was determinated by TLC-FABMS. The gypenoside A was hydrolysed with cellulase and the hydrolysate showed eight spots on a TLC plate, and the FABMS analysis of these spots indicated they corresponded to gypenoside A, A-Rham, A-Glu, A-Rham-Glu, A-Rham-Glu, A-Glu-Glu, A-Rham-2Glu, A-Rham-2Glu in order. Two chains can be determined to be Rham-Glu, and Glu-Glu, respectively. So the glycosyl sequence of gypenoside A was identical of gypenoside XLIII.

IgG1 and IgG4 serum antibody responses in asymptomatic and clinically expressed cystic echinococcosis patients

IgG1 and IgG4 subclass antibody responses were investigated in two clinically different groups of hepatic cystic echinococcosis (CE) patients. One group consisted of surgically proven CE cases (clinically expressed hospitalized cases) and a second group comprised asymptomatic CE patients (first time community detected cases) diagnosed by portable ultrasound and serology in four different endemic communities. Fifty eight sera from surgically proven CE patients and 133 sera from asymptomatic ultrasound diagnosed CE cases were screened by ELISA using purified human hydatid cyst fluid antigen B for total specific IgG, IgG1 and IgG4 antibodies. Fifty sera from healthy individuals from within endemic regions were used as control negatives. Compared to control negatives total IgG antibody levels were elevated in both surgically proven (85%) and asymptomatic CE cases (77%) but there was no significant difference between the two groups. IgG1 subclass antibody levels were also elevated in both surgically proven (55%) and asymptomatic cases (58%) compared to endemic controls and similarly the difference in this response was not significant between these two groups. In contrast the prevalence of IgG4 antibodies in surgically confirmed chronic CE patients was greater (71%) than the respective IgG1 antibody levels (55%). The greatest difference in specific antibody response, between advanced surgically confirmed CE patients and ultrasound detected asymptomatic CE cases, was observed for IgG4 antibody levels which were detected in 71% of symptomatic compared to only 23% of asymptomatic patients (P < 0.0001). These observations confirm that IgG4 is an important diagnostic parameter for clinically expressed cystic echinococcosis in humans and suggest that a switch from a predominant IgG1 response to IgG4 might occur in CE patients as the disease progresses.

Simulation of B1 field distribution and intrinsic signal-to-noise in cardiac MRI as a function of static magnetic field

Two issues that pertain to the optimal static magnetic field for cardiac MRI were addressed: intrinsic signal-to-noise ratio (ISNR) and radiofrequency power deposition. From 1.5 to 9.5 T, proton Larmor frequencies of 63 to 400 MHz, numerical simulations were performed of the RF fields from a surface coil and a body coil loaded by a heterogeneous, three-dimensional, symmetric model of the human chest. The RF field distribution, the power required to produce the RF field, and the ISNR at the center of the heart were computed. The model was validated by comparison with experimental data up to 4 T. The RF field distortion was quantified and found to increase linearly up to 6 T due mostly to dielectric resonance modes. Body coil simulations beyond 6 T showed the onset of higher-order modes at the center of the heart. A range of expected RF power requirements was constructed as a function of field up to 9.5 T for surface coils and up to 6.8 T for body coils. Over this range of static field, ISNR for a constant coil geometry was bracketed by an upper limit that was slightly greater than linear with field and a lower limit that was slightly less than linear with field. The RF power and ISNR showed a strong dependence on chest thickness at 1.5 and 4.0 T. Additionally, independent of chest thickness, the model predicts a lower limit of a factor of 5 increase in RF power as the static field is increased from 1.5 to 4 T. Implications for imaging with other nuclei are discussed. Methods for checking the self-consistency of electrodynamic simulations are presented.

A pilot, serological survey for cystic echinococcosis in north-western Mongolia

The seroprevalence of cystic echinococcosis in north-western Mongolia was determined in a cross-sectional study of 334 semi-nomadic pastoralists in their summer grazing areas. Overall, 5.2% of the subjects were found to be strongly seropositive for antibodies to Echinococcus granulosus antigen B by ELISA. Only 10% of the adult subjects (aged > or = 15 years) had heard of the disease and only 5% recognized hydatid cysts in their livestock (in contrast to the neighbouring province in China, where 76% had seen and recognized cysts in the organs of slaughtered animals). The close association between Mongolian pastoralists, their dogs and livestock is likely to encourage ready transmission of the parasite in a region where home slaughter is practised and offal for various scavengers, including domestic dogs. Further information is needed to determine the prevalence of infection in other intermediate hosts and in dogs and the clinical importance of the disease in this remote region.

[Prognosis and prognostic factor analysis epithelial ovarian cancer]

OBJECTIVE

To investigate the prognosis change and prognostic factors of advanced epithelial ovarian cancer in recent over twenty years.

METHODS

One hundred and fourty patients with advanced epithelial ovarian cancer were analyzed. They were divided into two groups based on their operation time. 56 patients operated before Jan. 1980 were included in the first group, and the other 84 patients in the second group. Kaplan-Meier survival curves of the two groups were calculated, and Cox model was used to evaluate the prognostic factors of the disease at univariate and multivariate levels using SPSS and SURVCALC software.

RESULTS

There was no pathological difference in between the two groups, but the patients in the second group received more aggressive chemotherapy. The overall 1-, 2-, and 5-year survival rates were 61.2%, 32.1%, and 8.5%, respectively. In the first group they were 42.3%, 29.6% and 4.5% respectively and in the second group 69.3%, 36.2%, and 11.2% respectively. The prognosis of the patients in the second group was better than that in the first group, P < 0.05. Univariate analysis revealed that stage, grade, residual tumor size and chemotherapy were significant predictors of patients' outcome. COX regression analysis identified that they were all independent prognostic factors. The patients with advanced, low grade, residual tumor (> 2 cm) had poor prognosis. The prognosis of the patients who received equal or more than four, especially six cycles combined chemotherapy was improved.

CONCLUSION

The prognosis of the patients with advanced ovarian cancer has improved in recent over 10 years, higher optimal cytoreductive rate and equal or more than six cycles combined chemotherapy are important measures for the better prognosis of advanced ovarian cancer.

The intrinsic signal-to-noise ratio in human cardiac imaging at 1.5, 3, and 4 T

Cardiac imaging is inherently demanding on the signal-to-noise performance of the MR scanner and may benefit from high field strengths. However, the complex behavior of the radiofrequency field in the human body at high frequencies makes model-based analyses difficult. This study aims to obtain reliable comparisons of the signal-to-noise profile in the human chest in vivo at 1.5, 3, and 4 T. By using an RF-field-mapping method, it is shown that the intrinsic signal-to-noise increases with the field strength up to 4 T with a less than linear relation. The RF field profile is markedly distorted at 4 T, and the onset of this distortion is dependent on the body size. The high power deposition and the consequences of the RF field distortion are discussed.

Antibody responses against Em18 and Em16 serodiagnostic markers in alveolar and cystic echinococcosis patients from northwest China

Western blot analysis was carried out in order to evaluate new serodiagnostic markers, Em18 and Em16, for differentiation of alveolar echinococcosis (AE) from cystic echinococcosis (CE) using 36 serum samples from hydatid patients from Xinjiang, China, where AE and CE are both endemic and one double infection case has been reported. All AE cases except one (5/6) who exhibited a calcified lesion and a single case of double infection showed antibody responses against Em18 and Em16. Some of CE patient sera (6/22) showed antibody response against Em16 except one who showed that against Em18. Analyses of IgG subclass responses against Em18 and Em16 were carried out using all serum samples showing antibody responses against Em18 and/or Em16 (seven CE, five AE, and one AE + CE) and additional samples of three CE and 22 AE from Sichuan, China. IgG4 was the most predominant antibody subclass. Em18 and Em16 were recognized by both IgG4 and IgG1 (in most cases) or by either IgG4 or IgG1 (in minor cases) or by IgG3 (in very rare cases). Neither Em18 nor Em16 was recognized by IgG2 antibodies. The usefulness of Em18 and Em16 as potential new markers for serological differentiation of human AE and CE, respectively, is discussed.

[Plasma and skin tissue endothelin in patients with psoriasis vulgaris]

The levels of plasma endothelin in 46 patients with psoriasis vulgaris and the levels of endothelin in skin tissue of 25 cases were determined by RIA. The results showed that: (1) The plasma levels of endothelin in patients with psoriasis vulgaris was significantly increased compared with that of the controls (P < 0.01), so was the active stage group compared with the stable stage group (P < 0.01); (2) The level of endothelin in skin lesions of patients was significantly higher than that of the uninvolved skin. These findings suggest that endothelin might play a role in the pathogenesis of psoriasis vulgaris.

[Mutations of p53 gene exons 5 to 8 in human ovarian cancer and its clinical significance]

OBJECTIVES

To detect p53 mutations in human ovarian cancer and to look for correlations between p53 mutation and clinicopathologic features.

METHODS

Mutations in exons 5-8 of p53 gene in 41 patients with primary ovarian cancer were screened by polymerase chain reaction-single strand conformation polymorphism analysis with non-isotopic silver staining method.

RESULTS

Mutations of p53 were found in 17 cases (41.5%); p53 mutation was not correlated with the age, the FIGO stage and the histologic type of the patients. However, it was associated with grade and lymph node metastasis in a univariate analysis.

CONCLUSION

Mutations of p53 occur commonly in human ovarian cancer. p53 mutation is an early event in ovarian carcinogenesis and may serve as a genetic marker for early diagnosis and prognosis.

A method to improve the B0 homogeneity of the heart in vivo

A homogeneous static (B0) magnetic field is required for many NMR experiments such as echo planar imaging, localized spectroscopy, and spiral scan imaging. Although semi-automated techniques have been described to improve the B0 field homogeneity, none has been applied to the in vivo heart. The acquisition of cardiac field maps is complicated by motion, blood flow, and chemical shift artifact from epicardial fat. To overcome these problems, an ungated three-dimensional (3D) chemical shift image (CSI) was collected to generate a time and motion-averaged B0 field map. B0 heterogeneity in the heart was minimized by using a previous algorithm that solves for the optimal shim coil currents for an input field map, using up to third-order current-bounded shims (1). The method improved the B0 homogenelty of the heart in all 11 normal volunteers studied. After application of the algorithm to the unshimmed cardiac field maps, the standard deviation of proton frequency decreased by 43%, the magnitude 1H spectral linewidth decreased by 24%, and the peak-peak gradient decreased by 35%. Simulations of the high-order (second- and third-order) shims in B0 field correction of the heart show that high order shims are important, resulting for nearly half of the improvement in homogeneity for several subjects. The T2* of the left ventricular anterior wall before and after field correction was determined at 4.0 Tesis. Finally, results show that cardiac shimming is of benefit in cardiac 31P NMR spectroscopy and cardiac echo planar imaging.

Pharmacology and efficacy of liposome-entrapped albendazole in experimental secondary alveolar echinococcosis and effect of co-administration with cimetidine

Encapsulation of the benzimidazole albendazole in multilamellar liposomes results in a preparation in which this normally insoluble anti-hydatid drug is well solublilized in aqueous media. The high entrapment efficiency observed (75-87%) and the stability of the formulation make this a promising delivery vehicle for improved chemotherapy with albendazole. In particular, the high degree of association with phospholipid may give rise to increased oral bioavailability. Oral administration of albendazole in liposomes led to increased concentration and/or altered metabolism of albendazole sulphoxide (ABZSX) in liver and/or plasma in non-infected Wistar rats. Results from experiments using cotton rats (Sigmodon hispidus) infected with metacestodes of Echinococcus multilocularis show that entrapment within liposomes clearly increases the uptake of albendazole via the oral route. This was reflected by increased levels of albendazole and the two major metabolites in plasma, liver and cyst homogenate when a dose of liposomal albendazole (35 mg/kg) was given orally compared to free albendazole at 50 mg/kg. There was a 75-94% reduction in biomass of the metacestode and a significant increase in survival time for the animals treated with liposome entrapped albendazole. A clear difference in distribution of albendazole and its metabolites in the liver and the metacestode tissues in the presence of cimetidine indicated that the latter has a profound effect on the metabolism of albendazole. There appeared to be a synergistic interaction between albendazole and cimetidine, since the metabolism of albendazole was markedly altered in the combined cimetidine/ liposome-albendazole group, and higher therapeutic effect was observed. These findings indicate potential both for improvement of treatment of larval E. multilocularis infection and for reduction of albendazole dose levels.

MR imaging contrast in human brain tissue: assessment and optimization at 4 T

PURPOSE

To evaluate multiple magnetic resonance (MR) imaging sequences for their ability to provide T1 and T2-weighted images at a field strength of 4 T, and to validate previously obtained relaxation time measurements.

MATERIALS AND METHODS

Different spin-echo, inversion-recovery (IR), gradient-recalled acquisition in the steady state (GRASS), and magnetization transfer contrast-enhanced GRASS sequences were evaluated in a single section, each in at least four volunteers. Also, interleaved echo-planar imaging (IEPI) and interleaved gradient-recalled echo (IGRE) sequences were analyzed and compared with standard sequences.

RESULTS

Predicted contrast behavior, according to MR relaxation time measurements, was found to agree well with that of the validation experiments. Fair T1 contrast can be achieved on MR images at 4 T, contrary to early predictions. Under other conditions, however, such as partially spin-density-weighted parameters, lower contrast is observed at the high field strength when compared with conventional field strengths.

CONCLUSION

The longer T1 values at higher field strengths have a substantial effect on image contrast. Depending on the sequence and parameters chosen, good image contrast can be realized at 4 T. IEPI and hybrid IR IGRE sequences are useful in shortening the prolonged examination times owing to the longer T1 values at higher field strengths.

The evaluation of dielectric resonators containing H2O or D2O as RF coils for high-field MR imaging and spectroscopy

Electromagnetic resonators consisting of low-loss dielectric material and/or metallic boundaries are widely used in microwave technologies. These dielectric resonators usually have high Q factors and well-defined field distributions. Magnetic resonance imaging was shown as a way of visualizing the magnetic field distribution of the resonant modes of these resonators, if the dielectric body contains NMR sensitive nuclei. Dielectric resonators have also been proposed as RF coils for magnetic resonance experiments. The feasibility of this idea in high-field MR is discussed here. Specifically, the dielectric resonances of cylindrical water columns were characterized at 170.7 MHz (4 T 1H Larmor frequency), and evaluated as NMR transmit and receive coils. The dielectric resonance of a cylindrical volume of D2O was used to image a hand at 170.7 MHz. This study demonstrated that MRI is an effective way of visualizing the magnetic field in dielectric structures such as a water cylinder, and can potentially be generalized to solid-state dielectric devices. The possible applications of dielectric resonators other than simple cylindrical volumes in MRI and MR solution spectroscopy at high field strengths are also discussed.

An in vivo automated shimming method taking into account shim current constraints

Many in vivo imaging techniques require magnetic field homogeneity in the volume of interest. Shim coils of the second and third order spherical harmonics have been used successfully to compensate for complicated field variations caused by the human anatomy itself. The available currents of these coils are invariably limited. In this note we demonstrate that these limits significantly affect the optimal shim condition. We propose an automated in vivo shimming method for arbitrary volumes of interest using 3-dimensional (3D) field maps. This method is a modification of previous works using least-squares criteria. The main difference is that a constrained optimization is performed in vivo under the current limits of the shim coils, which improved the field homogeneity significantly over simple truncations of the least-squares solutions. This shimming method was used with head scans of five normal volunteers on a 4.0 tesla scanner. A fast double-echo sequence was used to obtain field maps, and a new field uniformity measure was derived for this method. The field mapping sequence was tested against a standard single-echo Dixon sequence used by previous investigators, and the stability of the shimming method was tested by repeated studies on the same subject.

[Diagnosis and treatment of postmenopausal uterine bleeding by hysteroscopy]

OBJECTIVES

To evaluate the value of hysteroscopy in diagnosis and treatment of patients with postmenopausal uterine bleeding.

METHODS

One hundred and thirty-five patients with postmenopausal bleeding hospitalized in our department from July 1990 to July 1994 were examined by hysteroscopy. The results of 124 cases were compared with pathological findings obtained during uterine curettage. Thirty-nine patients were operated simultaneously under hysteroscopy.

RESULTS

Under hysteroscopy, atrophic endometrium, endometrial polyps, cervical polyps, endometrial carcinoma, endometrial hyperplasia, submucous myoma were diagnosed in 62 cases (45.9%), 25 cases (18.5%), 13 cases (9.6%), 13 cases (9.6%), 11 cases (8.2%) and 5 cases (3.7%) respectively. The remaining 6 (4.5%) had IUD insertion. These findings were confirmed pathologically in 115 out of 124 cases (92.7%). There were 9 cases misdiagnosed by hysteroscopy. 6 cases had false negative results during previous curettage. Twenty-two cases of endometrial polyps, 13 cases of cervical polyps and 4 cases of pediculated submucous myoma were removed hysteroscopically without any complication.

CONCLUSIONS

Hysteroscopy is an effective method for identifying the causes of postmenopausal uterine bleeding, which is superior to curettage of uterus. For some selected patients hysteroscopic operations can be performed at the same time.

Radiofrequency shielding of surface coils at 4.0 T

Because radiation loss associated with a radiofrequency (RF) coil increases as roughly the fourth power of the frequency, this loss mechanism may become important in high-field studies above 2.0 T. In this study, the contribution of radiation losses at 4.0 T were determined in a rectangular surface coil using an RF shield to modify the radiation losses. The effect of this shield was determined on coil Q, B1 distribution, and signal to noise as a function of distance between the coil and the shield. Phantoms and human tissue were evaluated to characterize the loss mechanisms. The results demonstrate a large radiation loss in the unshielded surface coil. However, the radiation losses in vivo were not dominant owing to a large inductive loss occurring from dielectric currents in the body at 170 MHz.

Analysis of immunoglobulin G subclass in the serum antibody responses of alveolar echinococcosis patients after surgical treatment and chemotherapy as an aid to assessing the outcome

Immunoglobulin G (IgG) subclass-specific antibody responses were evaluated for the follow-up of alveolar echinococcosis (AE) patients. Seventy-four sequentially collected sera from 25 Chinese and French AE cases who underwent surgery including hepatectomy, liver transplant and/or chemotherapy were analysed quantitatively and qualitatively during the clinical follow-up period. These AE patients were classified in 4 groups--cured, improved, stabilized, or aggravated. Serum antibody levels of the subclasses IgG1 and IgG4 were significantly higher in the AE patients than in healthy controls. IgG1 and IgG4 isotypes in AE patients were the most sensitive IgG antibody response in an enzyme-linked immunosorbent assay (ELISA) and in binding to antigens of 44kDa, 35kDa, 21kDa and 17.5kDa in an Echinococcus multilocularis protoscolex extract after Western blotting. In AE cases classed as cured or improved, IgG subclass antibody levels tended to decrease earlier than total IgG levels, especially IgG4 antibody levels which became negative within one year after successful treatment. IgG4 antibody levels also decreased in most of the improved cases. Increasing or unchanged levels of IgG4 and IgG1 antibodies were demonstrated in both stabilized and aggravated AE cases using both ELISA and immunoblot assays. Reappearance of specific IgG4 antibodies was a strong indication of recurrence, especially in liver transplant patients. Combined quantitative and qualitative assessment of IgG1 and IgG4 antibodies may be potentially useful for the serological follow-up of human AE.

Immunoblot evaluation of IgG and IgG-subclass antibody responses for immunodiagnosis of human alveolar echinococcosis

Antigen binding of total-IgG and IgG-subclass antibodies from patients with alveolar or cystic echinococcosis (AE and CE) was assessed by immunoblotting. Antigen extracts were prepared from Echinococcus multilocularis protoscoleces (EmP) or from homogenized E. multilocularis metacestode tissue (EmCH). Antigens of approximately 44, 35, 21, 17.5 and 16.5 were recognized by total-IgG and IgG1- and IgG4-subclass antibodies in some of 50 human AE sera from China, Japan or France. The 44- and 35-kDa polypeptides, present in both EmP and EmCH extracts, were recognized by total-IgG antibodies in sera from 82% and 66% of the AE patients, respectively. However, over 30% cross-reactivity occurred between these two antigens and sera from CE and Taenia solium cysticercosis patients. The immunoblot specificities of the 27-, 21- and 17.5-kDa antigens in EmP for E. multilocularis infection were 73%, 88% and 93%, respectively. Recognition of the 17.5-kDa antigen in the EmP immunoblot was much higher for the Japanese AE cases (11/13; 85%) than for the French (9/19; 47%) or Chinese (9/18; 50%) AE cases. None of the CE cases from Uruguay or Libya, where human AE has not been reported, was seropositive for the 17.5-kDa antigen. Antibodies from three (7.3%) of the 41 Chinese CE cases recognized the 17.5-kDa antigen. Within the 13 Japanese AE sera, the combined detection by IgG1, IgG4 and total-IgG antibodies of the 27-, 21- and 17.5-kDa antigens in either EmP or EmCH immunoblots was greater than that by each class/subclass alone, increasing the overall sensitivity for AE patients. A combined ELISA/immunoblot approach, including IgG-subclass detection using E. multilocularis protocolex or cyst extracts, could be useful for the differential diagnosis of human alveolar echinococcosis. An algorithm for such an approach is given.

Musculoskeletal MR imaging at 4 T and at 1.5 T: comparison of relaxation times and image contrast

PURPOSE

To evaluate the relaxation time-based contrast between the main tissues of the musculoskeletal system as measured in the human knee with magnetic resonance imaging at 4 T and 1.5 T.

MATERIALS AND METHODS

Five volunteers underwent 4-T and 1.5-T imaging. Inversion-recovery series were used to measure T1 values, and T2 values were measured with a spin-echo sequence.

RESULTS

T1 values increased in all tissues with 4-T imaging. Values increased in muscle from 1 to 1.8 seconds, in fat from 0.3 to 0.4 seconds, and in cartilage from 0.8 to 1.5 seconds. T2 values were 10%-20% shorter in all tissues at 4 T.

CONCLUSION

Advantages of 4-T imaging compared with 1.5-T imaging include a higher signal-to-noise ratio and an improved signal difference-to-noise ratio. However, any improvement in signal-to-noise ratio at high field strengths can partially be reduced by the increase in the T1 value. The slightly shorter T2 values at 4 T do not affect image contrast.

Binaural noise suppresses linear click-evoked otoacoustic emissions more than ipsilateral or contralateral noise

We studied the efferent suppression of click-evoked otoacoustic emissions with 65 dB SPL of white noise presented to left, right, or sometimes both, ears for 408 ms. Each burst of noise preceded a series of four unipolar 80 microseconds 65 dB peak Sound Pressure clicks, presented to the left ear only. The first click of the four-click group followed the end of the noise by either 1, 2, 5, 10, 20, 50, 100 or 200 ms; each subsequent click was offset by 20 additional ms via an ILO88 system with special programming modifications. Conditions were alternated so that a 'without noise' condition preceded a 'with noise' condition for three repetitions of 600 clicks per trial. Seven subjects with normal hearing participated in the study, and three of the seven participated in a test-retest reliability study. Results showed the greatest suppression followed binaural stimulation ending within one to five ms of the first click in the pulse train. Somewhat less suppression was seen following ipsilateral stimulation. The least amount of suppression was seen following contralateral stimulation, suggesting that previous research using contralateral stimulation may underestimate efferent effects. We saw no effects when the end of the noise was 100 ms or more away from the beginning of the click train.

Immunoblot evaluation of the 100 and 130 kDa antigens in camel hydatid cyst fluid for the serodiagnosis of human cystic echinococcosis in Libya

Two high molecular weight antigens with molecular masses approximately 100 kDa and 130 kDa were identified by immunoblotting camel hydatid cyst fluid, with 94% sensitivity in sera from surgically confirmed Libyan cystic echinococcosis cases. 40% of sera from surgically confirmed alveolar echinococcosis cases cross-reacted with the 100 and 130 kDa antigens, as did 5.3% of sera from human Taenia solium cysticercosis patients. No cross-reaction occurred with sera from human schistosomiasis mansoni or onchocerciasis patients. In addition, all sera from patients with non-hydatid space-occupying lesions (i.e. simple liver cysts, kidney cysts, lung tuberculosis, pulmonary carcinoma, pulmonary empyema, and lung abscess) were seronegative against the same antigens, as were control serum samples from healthy individuals. The 100 and 130 kDa antigens were strongly recognized by sera from cystic echinococcosis patients when camel or horse hydatid cyst fluid was used in immunoblotting but were only weakly recognized if sheep or human hydatid cyst fluid was used. Camel hydatid cyst fluid could be an important source of diagnostic antigens for human cystic echinococcosis in the Middle East endemic region.

[Clinical study on treatment of male infertility with shengjing pill]

202 cases of male infertility were treated with Shengjing Pill. After treatment, quantity and quality of sperm were significantly improved (P < 0.001), levels of follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) were enhanced to normal in 96 patients (P < 0.001), levels of anti-sperm-antibody was reduced to normal in 45 cases (P < 0.001), of 148 follow-ups. Their 116 spouses became pregnant and have borne 108 well-developed babies.

Immunoglobulin G subclass responses in human cystic and alveolar echinococcosis

Immunoglobulin G (IgG) subclass-specific antibody responses were investigated in both human cystic echinococcosis (CE) and alveolar echinococcosis (AE) by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Sera were tested from 81 CE and 50 AE surgically confirmed cases using partially purified hydatid cyst fluid antigen B (EgB), and crude hydatid cyst fluid (EgCF) from Echinococcus granulosus and a protoscolex extract (EmP) prepared from E. multilocularis metacestodes. Eighty-nine percent of CE patients and 94% of AE patients were seropositive for total IgG antibodies. The dominant IgG antibody isotype in both CE and AE was IgG4, for which 73% of CE and 84% of AE cases were seropositive in the ELISA. Anti-Echinococcus IgG1 antibodies were detected in 58% of CE and 84% of AE patients. Sensitivity for IgG2 and IgG3 was significantly lower for both CE and AE patients. The IgG4 antibodies in CE patients predominantly recognized the E. granulosus antigen B subunits, i.e., at 20, 16 and 12 kD, while IgG1 antibodies primarily bound to the 38-kD subunit of antigen 5 from E. granulosus hydatid fluid. The possible functional significance of an IgG4 response and the potential use of combined assessment of total IgG, IgG1, and IgG4 antibodies in serologic diagnosis and follow-up for human echinococcosis are discussed.

The design and test of a new volume coil for high field imaging

A major problem in the development of high field (> 100 MHz) large volume (> 6000 cm3) MR coils is the interaction of the coil with the subject as well as the radiation loss to the environment. To reduce subject perturbation of the coil resonance modes, a volume coil that uses an array of freely rotating resonant elements radially mounted between two concentric cylinders was designed for operation at 170 MHz. Substantial electromagnetic energy is stored in the resonant elements outside the sample region without compromising the efficiency of the overall coil. This stored energy reduces the effect of the subject on the circuit and maintains a high Q, facilitating the tuning and matching of the coil. The unloaded Q of the coil is 680; when loaded with a head, it was 129. The ratio of 5.3 of the unloaded to loaded Q supports the notion that the efficiency of the coil was maintained in comparison with previous designs. The power requirement and signal-to-noise performance are significantly improved. The coil is tuned by a mechanism that imparts the same degree of rotation on all of the elements simultaneously, varying their degree of mutual coupling and preserving the overall coil symmetry. A thin radiofrequency shield is an integral part of the coil to reduce the radiation effect, which is a significant loss mechanism at high fields. MR images were collected at 4T using this coil design with high sensitivity and B1 homogeneity.

Albendazole chemotherapy for human cystic and alveolar echinococcosis in north-western China

Human echinococcosis is highly endemic in north-western China; the main treatment is by surgery. In this paper, we report the results of chemotherapy with albendazole (ABZ), 15-20 mg/kg/d orally, for 30 d with intervals of 10 d between treatments for 3-6 courses. For multi-organ cystic echinococcosis (CE) and alveolar echinococcosis (AE), patients were given 12-18 courses of ABZ. Patients were divided into 4 groups: (i) ABZ surgery group, albendazole with surgery for 21 CE cases: (ii) non-ABZ surgery group, 80 CE cases treated by surgery alone; (iii) ABZ CE group, albendazole treatment alone in 58 CE cases, and (iv) ABZ AE group, 14 AE patients treated by albendazole and surgical intervention and 5 AE patients treated by albendazole alone. Twenty-seven of 34 (79.4%) cysts in group (i) patients showed increased necrotic changes and decreased viability of the cysts compared to group (ii). However, 10 of 84 (11.9%) cysts in group (ii) patients showed spontaneous evidence of necrosis at surgery. In group (iii), ABZ treatment alone was successful in 14 (24.1%), resulted in improvement in 29 (50%) and had no effect in 15 (25.9%) patients. Seven cases in group (iv) improved, with diminished size of lesions which were non-viable. The remaining 7 cases in group (iv) showed evidence of cyst viability at surgery; 2 could not be saved after a further 15 courses of albendazole. Of the five AE patients in group (iv) who received only ABZ, one improved, 2 stabilized, one deteriorated and one died. Albendazole chemotherapy, while not completely effective, has an important role in treatment of both cystic and alveolar echinococcosis.

Comparison of EPI gradient-echo contrast changes in cat brain caused by respiratory challenges with direct simultaneous evaluation of cerebral oxygenation via a cranial window

A gradient-echo echo planar imaging (EPI) sequence has been used to generate images of cat brain during respiratory challenges. Direct spectrophotometric measurements have been made simultaneously in order to correlate the changes in oxygen saturation as measured by spectrophotometry with the image intensity changes seen in the gradient-echo images. When blood volume remains approximately constant, as derived from the spectrophotometry data, good correlation is seen between calculated plots made of changes in the transverse relaxation rate, delta R2*, and the oxygen saturation as measured by spectrophotometry for much of the time course of the respiratory challenges of anoxia, apnea and hypercapnia. In some cases, the correlation is poorer during the recovery periods of the apnea and anoxia challenges. Those lower correlations can often be accounted for by changes in blood volume, which also affects the NMR relaxation rate. These results contribute to the understanding of the image intensity changes seen during functional brain imaging studies in humans.

Initial observation on albendazole in combination with cimetidine for the treatment of human cystic echinococcosis

Concentrations of albendazole were measured, by high-pressure liquid chromatography, in 19 patients being treated for cystic echinococcosis. All of the patients were given three 4-week courses of albendazole (20 mg/kg/day), separated by 10-day-long drug-free intervals. Seven patients also received three courses of cimetidine (10 mg/kg/day). Concentrations of albendazole sulphoxide (ABZSX) were significantly higher in samples of bile and hydatid cyst fluid from the patients receiving albendazole and cimetidine than in those from patients receiving albendazole alone (P < 0.05). The therapeutic benefit of the combined drug treatment, which was well-tolerated, was more than that with albendazole alone.

The First Jerger Lecture. Contralateral suppression of otoacoustic emissions: an index of the function of the medial olivocochlear system

We can now distinguish, in part, between nerve deafness and hair cell deafness through the use of otoacoustic emissions. We can also assess the efferent system by carefully quantifying the effects of contralateral stimulation on these same otoacoustic emissions. The suppression of transient evoked emissions by continuous contralateral white noise is an ostensibly small effect of 2 or 3 dB when studied over a 20-msec window. However, when subjected to microstructural analysis, the effect can exceed 6 to 8 dB in the zones from 10 to 20 msec after the stimulus has subsided. Temporal and spectral analyses reveal robust effects of contralateral lateral stimulation, although in any given normal subject it may be difficult to separate middle ear effects from efferent effects. Evidence is strong that the efferent effect is mediated in part by cholinergic-primarily nicotinic-receptors in the outer hair cell. However, a unique type of patient, who shows nearly normal pure-tone audiograms and absent ABRs, shows virtually no contralateral suppression of transient evoked emissions. Some other patients, with symptoms of Charcot-Marie-Tooth disease, may paradoxically show extremely poor audiograms, but perfectly normal evoked emissions along with absent contralateral suppression. The ABR, along with middle ear muscle reflexes and masking level differences, are all absent in these patients; we therefore think they have a disorder that desynchronizes most of their primary auditory nerve fibers and thereby disconnects them from any efferent activity or masking cancellation. The existence of such an auditory disorder, characterized by severe dysfunction in speech comprehension-especially when listening in noise-suggests that what appears to be a "central auditory imperception" might stem instead from a systemic peripheral primary neuropathy.

Contralateral suppression of non-linear click-evoked otoacoustic emissions

Click-evoked otoacoustic emissions from nominal 80 dB pSP (peak sound pressure) 80-microseconds pulses presented at 50 pulses per second were collected from the right ears of eleven normal hearing subjects using an ILO88 Otodynamic Analyzer in the non-linear mode. Clicks, pure tones, and narrow bands of noise were then presented to their left ears through insert earphones. The 80-microseconds contralateral clicks ranged in intensity from 80 dB pSP in 5 dB steps down to 60 dB pSP but data on only 10 of the subjects were collected successfully. The pure tones and narrow bands of noise centered at 250, 500, 1000, 2000, and 4000 Hz were also presented through insert phones at 20, 40, 60 and 80 dB HL (Hearing Level) to all 11 subjects. The mean overall 'echo amplitude' without contralateral stimuli was 11 dB SPL and underwent more than 3 dB of overall suppression in response to the noises which were the most effective of the contralateral suppressors. When we analyzed the echo suppression to noise in 2-ms segments, we found consistent contralateral suppression of 3-4 dB concentrated in the time zones after 8 ms. Time shifts of more than 200 microseconds between the control and experimental traces were also observed in the same zones. The clicks were the next most effective suppressors, but showed their amplitude and time effects in somewhat earlier time zones. The tones were the least effective suppressors suggesting that efferent effects we measured in the human system are not strongly tonotopic. Because 'non-linear' mode high intensity clicks were deliberately selected as stimuli to evoke the TEOAE's, the emissions and their suppression can represent neither the 'true' TEOAE nor all of the efferent system's suppression abilities.

Functional mapping of the human visual cortex at 4 and 1.5 tesla using deoxygenation contrast EPI

The effects of photic stimulation on the visual cortex of human brain were studied by means of gradient-echo echo-planar imaging (EPI). Whole-body 4 and 1.5 T MRI systems, equipped with a small z axis head gradient coil, were used. Variations of image intensity of up to 28% at 4 T, and up to 7% at 1.5 T, were observed in primary visual cortex, corresponding to an increase of blood oxygenation in regions of increased neural activity. The larger effects at 4 T are due to the increased importance of the susceptibility difference between deoxygenated and oxygenated blood at high fields.

Structural Study of an ent-Kaurane Lactone

The structure of the methyl ester derivative (2) of ent-20-hydroxy-16βH-kaurane-17,19-dioic acid 19,20-lactone has been determined by X-ray crystallographic methods. The δ-lactone ring adopts the chair conformation both in the solid state and in solution.