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Biomedical subjects

D H Xie

Publications and source records attributed to D H Xie.

17 recordsLinked to original sources
PubMed2004

Survey of intestinal parasites in pigs from intensive farms in Guangdong Province, People's Republic of China.

The prevalence of intestinal parasites was investigated in intensive pig farms in Guangdong Province, China between July 2000 and July 2002. Faecal samples from 3636 pigs (both sexes and five age groups) from 38 representative intensive pig farms employing different parasite control strategies were examined for the presence of helminth ova and protozoan oocysts, cysts and/or trophozoites using standard techniques. Of the 3636 pigs sampled, 209 (5.7%) were infected with Trichuris suis, 189 (5.2%) with Ascaris, 91 (2.5%) with Oesophagostomum spp., 905 (24.9%) with coccidia (Eimeria spp. and/or Isospora suis) and 1716 (47.2%) with Balantidium coli. These infected pigs were mainly from farms without a strategic anti-parasite treatment regime. Concurrent infection of multiple parasites was common, and T. suis was the most common nematode infecting breeding, young and mature pigs. The results of the present investigation provide relevant 'base-line' data for assessing the effectiveness of control strategies against intestinal parasitism in intensively raised pigs in Guangdong Province, China.

Animals↗
PubMed2001

Mutation and abnormal expression of the fragile histidine triad gene in nasopharyngeal carcinoma.

OBJECTIVE: To determine alterations of fragile histidine triad (FHIT) gene in nasopharyngeal carcinoma and the correlation of FHIT gene with nasopharyngeal carcinogenesis. STUDY DESIGN: Prospective study. METHODS: A total of 28 nasopharyngeal carcinoma and 16 normal nasopharyngeal epithelium specimens were examined for abnormalities of FHIT gene by nested reverse-transcriptase-polymerase chain reaction and DNA sequencing. RESULTS: The deletion of FHIT gene was not observed in 16 normal nasopharyngeal epithelium specimens. In 28 cases of nasopharyngeal carcinoma tissues, 12 (42.9%) exhibited FHIT aberrant transcripts. Complementary DNA sequencing revealed exonic deletion, small DNA insertion, synonymous mutation in exon 8, or frameshift mutation in exon 5. CONCLUSIONS: The present results suggest that the FHIT gene may play an important role in the pathogenesis of nasopharyngeal carcinoma and may be one of the candidate tumor suppressor genes in nasopharyngeal carcinoma.

Biopsy↗
PubMed2000

[Innervation of medial olivocochlear efferents in the cochlea of gerbils].

To explore the distributions of the medial olivocochlear (MOC) fibers and terminals in the cochlea of Mongolian gerbils and their physiological significance, a quantitative study on the distribution of MOC efferent fibers and terminals in whole cochlea of gerbils was performed using histochemical staining of acetylcholinesterase in the surface preparations. The relation between the density and size of MOC fibers and terminals in the cochlea and cochlear place-frequency map was analysed. The results were that the MOC fibers and terminals unevenly spreaded in the cochlea; the densest and the thickest MOC fibers and terminals were found in the distal part of the base turn and the second turn. These results demonstrate that the distribution of MOC fibers and terminals in the cochlea of gerbils is closely related to the function of frequency analysis of the cochlea.

Animals↗
PubMed2000

[The effect of chronic ototoxicity of gentamicin on the function of auditory efferents].

OBJECTIVE: To study the effect of chronic ototoxicity of gentamicin on the function of the cochlea and auditory efferents. METHOD: The effect of chronic ototoxicity of gentamicin on the function of the cochlea was determined by recording thresholds of the compound action potentials (CAP) of the auditory nerves to tone pip at 4, 6, 8, 10 and 12 kHz. The function of the medial olivocochlear (MOC) system was determined, through the observation of the effect of the contralateral noise (CLN) on CAP, before and after gentamicin administration. RESULT: The suppression effects of CLN on CAP were irreversibly eliminated, and the effects were most obvious at the 11th week after gentamicin (P < 0.01), and the response threshold of CAP was raised about 10 dB and 25 dB, respectively, at the 3rd and 11th week after the application of gentamicin. These results were most related to the morphological changes on cochlear efferents and hair cells. CONCLUSION: The auditory efferents play an important role in the chronic ototoxicity of gentamicin.

Animals↗
PubMed2000

[Benign paroxysmal positional vertigo following radiotherapy for nasopharyngeal carcinoma (report of 3 cases)].

OBJECTIVE: To investigate the effect of ionizing radiation on the vestibule of the inner ear. METHOD: Three patients with benign paroxysmal positional vertigo (BPPV) accompanied by hearing loss following radiotherapy for nasopharyngeal carcinoma (NPC) were reported. Particle repositioning maneuver (PRM) was used as treatment for BPPV, and salvia miltiorrhiza tablets were taken orally to treat hearing loss. RESULT: Two of three cases with BPPV recovered and one was effective; Mean phone frequency hearing increased 10 dB compared with that before therapy. CONCLUSION: Occurrence of BPPV in this series may be related to radiation damage on the vestibule; PRM is a effective modality for the patients with BPPV.

Adult↗
PubMed1998

Tonic efferent-induced cochlear damping in roosting and echolocating mustached bats.

The activity of the medial olivocochlear (MOC) efferent system in mustached bats, Pteronotus p. parnellii, was studied by monitoring changes in the mechanical properties of the cochlea. The changing properties were expressed by the decay time (DT) of cochlear microphonic potentials produced by transient-induced ringing (Henson et al., 1995). Tape-recorded roost noise (biosonar and communication sounds) produced sudden, marked decreases in DT when presented to the contralateral ear of animals adapted to the quiet. When the animals were first removed from their roosts the DT was relatively short (1.2-1.5 ms) but this gradually lengthened by about 0.5-1.0 ms as they rested in a quiet chamber. The time required to reach a stable, quiet-adapted state after noise exposure varied with SPL and exposure time; in many experiments recovery was in the range of 90-120 min. When quiet-adapted bats were isolated and allowed to fly and echolocate for 20 min, the DTs measured within a few minutes after the end of the flight were also short and only slowly returned to longer preflight values. The administration of a single dose of gentamicin, which blocks MOC effects, greatly reduced the amount of suppression (damping) observed after periods of noise and echolocation sound exposure. We conclude that tonic MOC activity is induced by the natural vocalizations and roost noise and this activity probably regulates and protects the highly resonant cochlear partition.

Adaptation, Physiological↗
PubMed1998

Mutations in the gene encoding gap junction protein beta-3 associated with autosomal dominant hearing impairment.

Hearing impairment is the most commonly occurring condition that affects the ability of humans to communicate. More than 50% of the cases of profound early-onset deafness are caused by genetic factors. Over 40 loci for non-syndromic deafness have been genetically mapped, and mutations in several genes have been shown to cause hearing loss. Mutations in the gene encoding connexin 26 (GJB2) cause both autosomal recessive and dominant forms of hearing impairment. To study the possible involvement of other members of the connexin family in hereditary hearing impairment, we cloned the gene (GJB3) encoding human gap junction protein beta-3 using homologous EST searching and nested PCR. GJB3 was mapped to human chromosome 1p33-p35. Mutation analysis revealed that a missense mutation and a nonsense mutation of GJB3 were associated with high-frequency hearing loss in two families. Moreover, expression of Gjb3 was identified in rat inner ear tissue by RT-PCR. These findings suggest that mutations in GJB3 may be responsible for bilateral high-frequency hearing impairment.

Adult↗
PubMed1996

The course and distribution of medial efferent fibers in the cochlea of the mustached bat.

The course and distribution of medial olivocochlear (MOC) nerve fibers were studied in the cochlea of the mustached bat. This animal is of interest because of the very sharp tuning of the ear and fine frequency resolution in small frequency bands near 60 and 90 kHz. The MOC fibers arise from about 400 cells in the dorsomedial periolivary (DMPO) nucleus and they are distributed to approximately 4500 outer hair cells (OHCs), resulting in an average OHC unit size of 11.25. Individual fibers appear to have a small number of branches and each branch entering the tunnel of Corti terminates on a patch of OHCs. The patch size is typically 1-3 OHCs with the smallest average patch sizes in the regions tuned to 60 and 90 kHz. The majority of the MOC terminals are derived from the contralateral DMPO. Contralateral vs. ipsilateral projecting fibers are not preferentially distributed within any of the three rows of OHCs or within specific regions throughout most of the cochlea. It can be concluded that the main differences between the mustached bat's MOC system and that of most other mammals are: (1) origin from a single nucleus; (2) relatively small sizes of the patches; (3) a single terminal on each OHC; (4) a gradient in the size of the terminals but not in the number of terminals from row to row or from base to apex.

Acetylcholine↗
PubMed1995

The effect of contralateral stimulation on cochlear resonance and damping in the mustached bat: the role of the medial efferent system.

In the unanesthetized mustached bat, stimulation of the ear with an acoustic transient produces damped oscillations which are evident in the cochlear microphonic potential. In this report we demonstrate how the decay time of these oscillations is affected by broadband noise presented to the contralateral ear (CLN). In the absence of CLN, the mean decay time was 1.94 +/- 0.23 ms, but during the presentation of CLN the decay time consistently decreased. The changes were finely graded, the higher the CLN, the greater the change. The effect could be maintained at a constant level for extended periods of time and this was evident when the CLN exceeded 40 dB SPL. The latency of the reflex for 64 dB noise was about 11 ms and near maximum changes occurred within 15 ms of CLN onset. Sectioning medial efferent nerve fibers in the floor of the fourth ventricle or the administration of a single dose of gentamicin eliminated changes produced by CLN. The prominence of CM responses to damped oscillations and the robust changes in response to CLN make the mustached bat an excellent model for studying the influence of the medial efferent system on cochlear mechanics.

Acoustic Stimulation↗
PubMed1994

AChE-staining of type II ganglion cells, processes and terminals in the cochlea of the mustached bat.

There have been a number of reports showing that ganglion cells of sensory neurons may be stained by traditional acetylcholinesterase (AChE) histochemical techniques commonly used to demonstrate efferent nerve fibers and terminals. AChE-staining has been described for cell bodies in the vestibular and spiral ganglia; staining of peripheral and central processes, however, is rare and the presence of reaction product in afferent terminals has not been reported. The outer hair cells of mustached bats, Pteronotus parnellii, differ from those of most mammals in that they typically have a single, large efferent terminal surrounded by 5-7 small, afferent terminals. In this animal an AChE-positive reaction was found not only in efferent fibers and terminals but also in type II ganglion cells, their peripheral and central processes and in outer hair cell terminals. The stained cell bodies were smaller than the unstained type I ganglion cells and they were much fewer in number. The processes of the stained cells could be followed from the soma. The central processes were dispersed throughout the VIIIth nerve trunk. Stained peripheral processes were evident in the osseous spiral lamina, floor of the tunnel of Corti and first space of Nuel and in the outer spiral plexus along the sides of the outer phalangeal (Deiters') cells. AChE-stained afferent terminals were easy to identify after transection of the crossed olivocochlear bundle (COCB) and subsequent degeneration of large efferent terminals. These results are of interest in that assessments of efferent nerve histochemistry after COCB transection need to recognize the potential contribution of AChE reaction product in afferent terminals.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗
PubMed1994

Doppler-shift compensation by the mustached bat: quantitative data.

Quantitative data for Doppler-shift compensation by Pteronotus parnellii parnellii were obtained with a device which propelled the bats at constant velocities over a distance of 12 m. The bats compensated for Doppler shifts at all velocities tested (0.1-5.0 ms-1). The main findings were (1) that compensation was usually accomplished by a progressive lowering of the approximately 61 kHz second harmonic constant-frequency component of emitted sounds in small frequency steps (93 +/- 72 Hz); (2) that the time needed to reach a steady compensation level averaged 514 +/- 230 ms and the number of pulses required to reach full compensation averaged 10.78 +/- 5.16; (3) that the animals compensated to hold the echo (reference) frequency at a value that was slightly higher than the resting frequency and slightly lower than the cochlear resonance frequency; (4) that reference frequency varied as a function of velocity, the higher the velocity of the animal, the higher was the reference frequency (slope 55 Hz m-1s-2); and (5) that the mean reference frequency was always an undercompensation. The average amount of undercompensation was 15.8%. There was a significant difference (P < or = 0.005) in Doppler-shift compensation data collected at velocities that differed by 0.1 ms-1. A velocity difference of 0.1 ms-1 corresponds to a Doppler-shift difference of about 35 Hz in the approximately 61 kHz signals reaching the ear.

Acoustics↗
PubMed1993

Efferent terminals in the cochlea of the mustached bat: quantitative data.

Efferent terminals in the cochlea of the mustached bat were stained for acetylcholinesterase (AChE) and quantitative data were obtained for the number and size of the endings on the outer hair cells (OHCs) in each row, from base to apex. From TEM micrographs and AChE-stained, surface preparations it was determined that every OHC had a single, large terminal. The mean size of the terminals was significantly different in each row, with the largest occurring in the first row (7.1 microns 2); the mean size in the second and third rows was 5.7 and 5.0 microns 2 respectively. In specific frequency processing regions, the largest mean size (8.4 microns 2) for first row OHCs was consistently found in the distal densely innervated (DDI) area. This region has afferent neurons that are sharply tuned to the second harmonic, constant frequency component of the bat's biosonar signals. Sudden changes in the size of the terminals were observed exactly at the boundaries of the DDI with adjacent sparsely innervated regions. Similar, but less striking, size changes also occurred in and adjacent to the proximal densely innervated (PDI) region, a harmonically related, sharply tuned region, which processes the bat's 91.5 kHz, third harmonic, constant frequency signals. The region of the cochlea with the smallest first row terminals (mean 5.3 microns 2) was the large, sparsely innervated region of the basal turn, a region that does not appear to process biosonar signals. Although the significance of differences in efferent terminal size is not known, the data suggest a possible correlation between OHC stimulation and sharp tuning. The potentially greater influence of the efferent fibers on the first row of OHCs, compared to other rows, is consistent with observations made on other mammals; in the latter, however, the greater influence has been suggested more by number than size. Unlike other mammals, the OHC efferents in the mustached bat have no clear base-to-apex gradient in the number or size of the efferent terminals. It is suggested that this might reflect the high frequency nature of the ear (6-120 kHz) and absence of low frequency hearing.

Acetylcholinesterase↗
PubMed1993

A comparative study of growth hormone (GH) and GH-releasing hormone(1-29)-NH2 for stimulation of growth in children with GH deficiency.

In this study, 60 patients with proven growth hormone deficiency (GHD) of hypothalamic origin were randomized into three equal groups, and received growth hormone-releasing hormone(1-29)-NH2 (GHRH(1-29)-NH2), 30 or 60 micrograms/kg/day, or growth hormone (GH), 0.1 IU/kg/day, for 6 months. There were no significant differences in growth between the two groups given GHRH(1-29)-NH2, but growth in the GH group was significantly better than in the other two groups (p < 0.01). Mean height velocities at 6 months were 9.2, 9.3 and 14.6 cm/year for the three groups, respectively. Plasma GHRH concentrations increased steadily over the 6-month treatment period, with higher levels in the group on the higher dose. During GHRH(1-29)-NH2 treatment, serum concentrations of insulin-like growth factor I rose initially, but then fell to values similar to those before treatment. No GH antibodies were detected, but all 20 patients on high-dose GHRH(1-29)-NH2 and 19 of 20 patients on low-dose GHRH(1-29)-NH2 developed GHRH antibodies. These had almost disappeared by 9 months after stopping treatment. There was no correlation between antibody titres and increase in height. No serious side-effects were seen, but three patients receiving GHRH(1-29)-NH2 reported mild irritation at the injection site. These results from the continuous infusion of GHRH(1-29)-NH2 over 6 months suggest that this treatment, or the related use of a depot preparation, is unlikely to be as effective as GH for the promotion of growth in GHD.

Age Determination by Skeleton↗
PubMed1992

Innervation of the endolymphatic sac.

Previous studies suggest that the endolymphatic sac plays an important role in the homeostasis of endolymph. Factors that influence blood flow in the sac may affect its function. This blood flow may be influenced by autonomic innervation; however, no such innervation has been demonstrated. The purpose of this study was to demonstrate catecholaminergic and cholinergic fibers on the endolymphatic sac. Endolymphatic sacs from Hartley guinea pigs were stained either immunocytochemically for tyrosine hydroxylase to reveal catecholaminergic fibers or histochemically for acetylcholinesterase to reveal cholinergic fibers. For tyrosine hydroxylase immunostaining, the endolymphatic sacs were treated with dilute hydrogen peroxide and then incubated in the primary antiserum. The tissue was further processed by the avidin-biotin immunoperoxidase method and reacted with diaminobenzidine. For acetylcholinesterase histochemistry, the tissue was processed by a modification of the direct thiocholine method. Light microscopy of the whole-mounted endolymphatic sacs revealed tyrosine hydroxylase-positive and acetylcholinesterase-positive fibers. Some of the acetylcholinesterase-positive fibers were clearly associated with vessels. This innervation, which has not been described previously, may significantly influence blood flow and function of the endolymphatic sac.

Acetylcholinesterase↗
PubMed1992

Cholinergic innervation of the guinea pig tympanic membrane.

While cholinergic nerve fibers of the parasympathetic system have been demonstrated in the middle ear mucosa, such innervation of the tympanic membrane has never been shown. Such fibers may prove important since the tympanic membrane may be one of the initial sites of effusion production, and since parasympathetic innervation is thought to be involved with middle ear effusion. To demonstrate cholinergic innervation, we have used modified direct thiocholine histochemical staining. Anesthetized Hartley guinea pigs were killed, and the tympanic bullae were removed intact, fixed in 4% paraformaldehyde, and then stained whole. Following staining, the tympanic membrane was dissected from each bulla and whole-mounted for light microscopy. Numerous acetylcholinesterase-positive fibers were observed on the tympanic membrane. Some fibers appeared to be vessel associated, although the majority did not. This suggests that these fibers may act on the mucosa or vasculature of the tympanic membrane and contribute to the pathogenesis of middle ear effusion.

Acetylcholinesterase↗