Audiological effect of bone-anchored hearing aid

The bone-anchored hearing aid (BAHA) has proved to be a valuable alternative to conventional air and bone conduction hearing aids for patients suffering from chronic otitis media or bilateral aural atresia. The BAHA gave better sound quality and greater comfort than conventional hearing aids (HAs), but only 1 study has been done in Japan. We implanted BAHAs in 6 hard-of-hearing patients in the last 2 years. One patient suffered skin problems around the abutment and used the BAHA only briefly. Free-field audiometry, the speech discrimination test (SDT), and the speech recognition test (SRT) were conducted in all subjects. They were evaluated either with the HA or BAHA. The SDT and SRT showed better hearing results in quiet for the BAHA than the conventional HA, but there was a minimum difference in SDT and SRT in noise. Subjects assessed the HA and BAHA using questionnaires. Subjects reported that the BAHA offers a number of important advantages, including greater cosmetic acceptability, improved speech intelligibility, and better sound quality.     

Transplantation of neural cells derived from retinoic acid-treated cynomolgus monkey embryonic stem cells successfully improved motor function of hemiplegic mice with experimental brain injury

We induced neural cells by treating cynomolgus monkey embryonic stem (ES) cells with retinoic acid. The treated cells mainly expressed betaIIItubulin. They further differentiated into neurons expressing neurofilament middle chain (NFM) in elongated axons. Half of the cells differentiated into Islet1+ motoneurons in vitro. The monkey ES-derived neural cells were transplanted to hemiplegic mice with experimental brain injury mimicking stroke. The neural cells that had grafted into periventricular area of the mice distributed extensively over the injured cortex. Some of the transplanted cells expressed the neural stem/progenitor marker nestin 2 days after transplantation. The cells expressed markers characteristic of mature motoneurons 28 days after transplantation. Mice with the neural cell graft gradually recovered motor function, whereas control animals remained hemiplegic. This is the first demonstration that neural cells derived from nonhuman primate ES cells have the ability to restore motor function in an animal model of brain injury.     

6-Hydroxydopamine-induced lesions in a rat model of hemi-Parkinson's disease monitored by magnetic resonance imaging

Injection with 6-hydroxydopamine (6-OHDA) into the nigrostriatal pathway results in loss of nigrostriatal dopaminergic neurons, which has been used widely as an animal model of Parkinson's disease. In the present study, location and extent of lesions 1 day after 6-OHDA injections (2, 4, 8, or 16 microg as a free base) in the substantia nigra (SN) were evaluated in rats by T(2)-weighted magnetic resonance imaging (MRI). The changes in MRI were also compared to immunohistochemical and behavioral changes. Hyperintense area in MRI was found at the region corresponding to 6-OHDA injection in a dose-dependent manner and was accompanied by a loss of tyrosine hydroxylase (TH)-positive cells. The shape of hyperintense area in the SN appeared to be composed of two components (i.e., circular and longitudinal regions). Administration of a larger dose of 6-OHDA (8-16 microg) was accompanied by an increase in hyperintense area and loss of TH-positive cells beyond the SN. The hyperintense area was observed on the first and third days after 6-OHDA injection, but the size and intensity declined to near normal levels on the ninth day. Rotational behavior induced by methamphetamine reached maximal levels at 4 microg 6-OHDA, and the behavior was maintained with doses up to 16 microg of 6-OHDA. Intrastriatal injection with 6-OHDA was less effective. These results suggest that MRI provides highly valuable information for verifying the size and location of intended lesions as well as for determining the optimal dose of neurotoxins in individual animals.     

Comparison of methods of attenuation and scatter correction in brain perfusion SPECT

OBJECTIVE: The radioactivity count distribution in the brain must be determined accurately to accurately measure cerebral blood flow (CBF). Scatter and attenuation are factors that compromise the accuracy of determining radioactivity counts in the brain. METHODS: We compared regional CBF in patients by an autoradiographic method using N-isopropyl-p-[123I] iodoamphetamine when, first, attenuation correction alone was performed uniformly on SPECT images by using empiric mu-values (Chang method); second, scatter correction was performed and the mu-values of a homogeneous-attenuation body of water were used for attenuation correction (triple-energy window [TEW]+Chang method); and third, scatter correction was performed and the mu-values calculated by CT were used for attenuation correction (TEW+CT method). We also compared regional CBF measured by these methods with the values obtained by the xenon CT/CBF method, which uses CT and stable xenon. RESULTS: Scatter correction reduced overestimation of regional CBF in low-flow regions. The TEW+CT method yielded better regional and overall correlations with the xenon CT/CBF method than did either of the other methods. CONCLUSION: The TEW+CT method of correction gave the most accurate measurements of regional CBF.     

Expression of DCC and netrin-1 in normal human endometrium and its implication in endometrial carcinogenesis

OBJECTIVE: Although DCC has been considered as a candidate tumor suppressor, the roles it plays in the uterine endometrium and in the carcinogenic process remains unclear. To define these roles more clearly, we examined the expression of DCC and its ligand, netrin-1, in the normal endometrium and in endometrial cancer. METHODS: The expression of DCC and netrin-1 in normal endometrial glands and in cancer cell lines was examined by RT-PCR and immunohistochemistry. The effects of exogenous DCC and netrin-1 expression were observed together with the respective expression vector transfection. RESULTS: Endometrial glands in the proliferative and early secretory phase expressed both DCC and netrin-1, but glands in the late-secretory phase tended to silence DCC expression. In addition, all of the endometrial cancer cell lines lost normal DCC expression. Restored DCC expression in the cancer cell lines in the absence of netrin-1 induced apoptosis. However, no changes were observed in the presence of netrin-1. CONCLUSION: Our observations suggest that DCC/netrin-1 signaling may commit cells to the transition of endometrial gland architecture or function from a proliferating to a secretory phase. In addition, the silencing of DCC expression may contribute to the escape of endometrial cancer cells from a DCC-regulated apoptotic program, thereby promoting malignant phenotypes.     

Analysis of limited fertility in intracytoplasmic sperm injection of sperm obtained by electroejactulation

Background and Aims :  We correlated findings in semen from patients with ejaculatory dysfunction with results of in vitro fertilization using their electroejaculated sperm.
Methods and Results :  Electroejaculation was carried out in six patients with the above-mentioned criteria for a total of eight times. Sperm was obtained in six attempts. Intracytoplasmic injection of these sperm was performed in 156 eggs. Sixty-seven eggs were fertilized; most of these were injected with motile sperm. Two women became pregnant, both after injection with motile sperm. As previously reported, electroejaculated sperm showed low motility and a low fertilization rate, but even motile sperm had a low fertilization rate.
Conclusion :  The results of the present study suggest the importance in fertilization of undetermined factors in addition to sperm motility. (Reprod Med Biol 2004; 3 : 9–12)     

Tracheal reconstruction with a prefabricated deltopectoral flap combined with costal cartilage graft and palatal mucosal graft

We have created an alternative method for tracheal reconstruction. Our new surgical procedure using a deltopectoral flap combined with a costal cartilage graft and mucosal graft for tracheal reconstruction allows us to achieve reconstruction of the tracheal mucosa, the tracheal cartilage, and the covering skin with adequate subcutaneous tissue. In one case, a tracheostenosis was reconstructed with a deltopectoral flap combined with a costal cartilage graft. In the other case, a tracheal defect was reconstructed with a deltopectoral flap combined with a costal cartilage graft and palatal mucosal graft. Although the operation is a multistage procedure, our method provides satisfactory clinical results. Thus, we believe that our method is useful for the surgical treatment of large tracheal defects.     

Intracranial hypovolemic syndrome with subdural hygroma developed massive hematoma: timing of treatment and histology of dural hypertrophy

We report a case of a 43-year-old man treated by craniotomy for chronical subdural hematoma (CSH) due to spontaneous intracranial hypovolemia. The patient complained of sudden onset severe headache. Initial CT scan showed normal brain structure, and his headache improved with bed rest in a few days. However, MR images obtained for vertigo one month later demonstrated bilateral subdural hygroma extending to the supracerebellar space and diffuse dural enhancement after gadolinium infusion. We diagnosed bilateral subdural hygroma due to spontaneous intracranial hypovolemia, and observed him conservatively. Four months after onset, he complained of severe headache again and MR images revealed enlargement of bilateral CSH with mass effect, which had heterogenous intensity on the right convexity. We evacuated hematoma on the right by craniotomy and aspirated the left side hematoma using a burr hole. His headache improved 2 weeks after the operation with strict bed rest. The follow-up MR images showed disappearance of abnormal meningeal enhancement and improvement of brain sagging.     

Study of the normal database that affects 3D-SSP Z-score mapping

The effects of image reconstruction conditions and devices used on 3D-SSP analysis (Z-score mapping) were investigated. Images of the 3D Hoffman brain phantom were taken with the IRIX device or E.CAM. Using two methods of image reconstruction (FBP and OSEM), several kinds of phantom normal databases (PNDB) and signal data, with or without correction for attenuation, were obtained at varying Butterworth filter cutoff frequencies. The results of 3D-SSP analyses were compared between combinations of PNDB and signal data obtained under the same conditions of image reconstruction and combinations obtained under different conditions. The results of PNDB obtained with different devices were also analyzed. For combinations of PNDB and signal data both obtained with OSEM, the Z-score of signals was high. When FBP was used to obtain both PNDB and signal data, the Z-score and signal size tended to become greater and the false-positive rate tended to decrease as the Butterworth filter cutoff frequency became lower. Whether or not correction for attenuation was incorporated did not affect the results of analysis when the same method was used to collect both PNDB and signal data. If the method for image reconstruction differed between PNDB and signal data, the false-positive rate was relatively high. Using a different device to obtain PNDB resulted in a relatively high false-positive rate. We therefore recommend that the conditions for image reconstruction from signal data should be matched to the conditions for image reconstruction from PNDB. It seems impossible to share the same NDB among different devices.