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Biomedical subjects

W M Hsu

Publications and source records attributed to W M Hsu.

At least 55 records · Page 3Linked to original sources
PubMed1999

Delayed-onset of Pseudomonas infection in a hydroxyapatite orbital implant: a case report.

Hydroxyapatite (HA) orbital implant, a multiple porous coralloid-like material, is frequently used in orbital reconstruction after enucleation or evisceration surgery. HA implants contain multiple interconnected pores in which rich fibrovascular tissue ingrowth could theoretically help to resist infection. Infection of hydroxyapatite implants are rare. Most HA implant infections occur before complete vascularization. We present this first case in Taiwan of delayed-onset Pseudomonas infection five years after receiving the HA implant. There was not much improvement after intensive medications, so removal of the implant was finally performed. The pathology study disclosed diffuse inflammatory cell infiltration in the whole implant with a necrotic central core. Rich fibrovascular ingrowth was also noted. Once a porous HA implant is infected, the infection is difficult to control and becomes more severe due to the dead space of the interconnected pores. Removal of the implant seems to be the only successful treatment modality.

Adult↗
PubMed1999

Solar retinopathy: a case report.

Sun-gazing is the main cause of solar retinopathy. A 20-year-old inebriated man lying in a park gazed at the sun for approximately three hours at noon. Forty-eight hours after sun-gazing, the patient experienced the symptoms of blurred vision, erythropsia, and central scotoma in the left eye. Visual acuity decreased from 6/6 to 6/60 in the left eye and fundi examinations showed a round, yellowish-white discoid lesion on the left fovea and a smaller one on the right fovea. Fluorescein angiography showed early dye leakage in the fovea of the left eye, that increased gradually in size and became fuzzy at the foveal border in the late phase. A small, central scotoma of the left eye was also found in the visual field test. One month later, the lesion in the fovea of the left eye became smaller and was surrounded by a coarse pigmented halo. Fluorescein angiography showed a window defect in the retinal pigment epithelium. Visual field testing disclosed that the central scotoma persisted, but became smaller. Six months after sun-gazing, a lamellar hole in the fovea of the left eye was detected by optical coherence tomography. The visual acuity was 6/6 in the right eye and 6/60 in the left eye, and was unchanged at the end of the six-month follow-up period.

Adult↗
PubMed1998

Anorectal function and endopelvic dissection in patients with repaired imperforate anus.

Fifty-eight patients with anorectal malformations were closely followed up for postoperative anorectal function. Constipation was noted shortly after anorectoplasty in 10 of 28 low anomalies (35.7%) treated with limited sagittal anorectoplasty (LSARP), in 18 of 25 high or intermediate anomalies (72.0%) treated with posterior sagittal anorectoplasty (PSARP), but in none of 5 high or intermediate anomalies treated with Rehbein's mucosa-stripping endorectal pull-through and anterior sagittal perineal anorectoplasty (R-ASAP). The constipation resolved mostly within 1-2 years after repair under conservative management, but persisted beyond 2 years after repair in 3/25 children with LSARP and 10/25 with PSARP. Anal soiling was noted in 1/23 (4.3%) LSARP and 6/22 (27.3%) PSARP patients, but normal anorectal function was attained in 20/23 LSARP (86.9%) and 11/12 PSARP patients (50.0%) by the time of toilet training. Manometric studies disclosed that the resting rectal pressure (RRP) was lower and the anorectal pressure gradient (ARPG) higher in the constipated than the non-constipated children, while the RRP was higher and the ARPG lower in the soiled than the non-soiled patients. The ARPG after R-ASPA was close to that of non-constipated and in between that of the constipated and soiled patients. The rectoanal sphincter inhibitory reflex was not related to defecation status or surgical procedures, but showed a tendency toward positive conversion with time or after exclusion of esctatic terminal bowel in the severely constipated. It is concluded that anorectal function in patients with repaired imperforate anus seems to be more affected by the extent of endopelvic dissection than by preservation of the terminal bowel or sphincter muscles.

Anal Canal↗
PubMed1997

Primary orbital hemangiopericytoma: a case report.

A case of primary orbital hemangiopericytoma is reported in a 31-year-old female presenting with progressive proptosis of the left eye and deteriorating diplopia over a period of 2 years. Orbital computed tomography revealed a superiorly located well-circumscribed extraconal mass. A 32x57x16 mm soft mass that appeared grossly encapsulated was removed intact via anterior orbitotomy. Histopathological examination disclosed it to be a hemangiopericytoma. The clinical importance is its potentially malignant behavior, with a high local recurrence rate in case of incomplete excision. Literature was reviewed.

Adult↗
PubMed1996

The salvage of a degloved hand skin flap by arteriovenous shunting.

Nine cases of hand degloving injuries were treated successfully with arteriovenous shunting technique. Of these nine cases, four were degloved from the wrist level and one from the forearm, three were degloved at the palm and one at the dorsum of the hand. All injuries resulted in distally based skin flaps, which were either superficial to the palmar fascia or within the subcutaneous layer. Lack of active bleeding from the periphery of the avulsed flaps substantiated circulatory compromise before revascularization. Survival of the avulsed flaps was achieved by directing the proximal arterial flow into the venous channel within the avulsed skin flaps. The post-operative care and rehabilitation were straightforward, and functional results were satisfactory.

Adolescent↗
PubMed1995

Retrograde dissection of the vascular pedicle in toe harvest.

A retrograde approach to dissection of the vascular pedicle in toe-to-hand transfer is presented, along with a simplified view of the vascular anatomy of the first web space. This approach has several advantages. First, the dominant vascular supply to the toe is elucidated early in the procedure, allowing for less unnecessary dissection of an inadequate pedicle. This also eliminates the need for preoperative arteriography. Furthermore, in cases where a lengthy pedicle is not required, retrograde dissection dispenses with harvest of a proximal vessel, which will not be needed for the transfer, and destructive dissection of the foot can be minimized.

Arteries↗
PubMed1994

Distal phalanx replantation.

Microsurgical replantation has been attempted in the distal phalanx of the digits. Twenty-three complete, single digit amputations are reviewed. The patients' ages ranged from 9 months to 48 years. Viability was 78%. Sensory recovery averaged 7 mm static two-point discrimination. Range of motion in the distal interphalangeal joint of the finger and the interphalangeal joint of the thumb averaged 64 and 51 degrees, respectively. Eight of the 17 successfully replanted digits had mild to moderate atrophy. Eighty-two percent of patients were able to use the replanted digit successfully in their daily work. We feel that distal digital replantation is rewarding. In successful cases, it always preserves acceptable function and good appearance at a price of an average of 2.3 months off work.

Adolescent↗
PubMed1994

Selection of recipient vessels for free flaps to the distal leg and foot following trauma.

The recipient vessels are of prime importance in free flap transfers to the lower limbs. To determine the incidence and pattern of vascular trauma, a study was carried out in 126 patients who had Gustillo Type III open fractures of the distal legs and feet that required free flaps for wound coverage. In comparison with the posterior tibial artery, the anterior tibial artery has a much higher incidence of injury with more extensive damage. It can be injured at a more proximal level than estimated from gross inspection during surgery. This should be borne in mind when the anterior tibial artery is selected as the recipient artery in order to prevent reexploration and failure of the flaps. However, the posterior tibial artery is much less vulnerable to damage in most injuries and is more reliable as the recipient artery. In this series there was no problem in finding proper recipient veins in the legs. A general principle is proposed for selecting recipient vessels in crushed legs, with a warning against the pitfalls that have been encountered.

Adolescent↗
PubMed1991

Rearrangements of immunoglobulin gene and oncogenes in ocular adnexal pseudolymphoma.

The organization of immunoglobulin heavy chain (IgH), light chain (kappa and lambda) and T cell receptor (TCR) beta chain gene loci in 10 patients with ocular adnexal pseudolymphoma was investigated. Eight of them showed IgH gene rearrangement in at least one of the 3 restriction enzymes-digested DNAs extracted from ocular adnexal neoplasms. In contrast, none of them exhibited clonal TCR beta chain gene rearrangement. The configuration of bcl-1, bcl-2 and c-myc oncogenes was also studied by Southern blot technique. Two patients had a rearranged joining region, IgH-containing fragment that comigrated with the rearranged bcl-1 fragment. C-myc gene rearrangement was found in only one patient who also had bcl-1 gene rearrangement. In ocular adnexal pseudolymphoma, none demonstrated bcl-2 gene rearrangement; however, in bone marrow cells, one patient with systemic lymphadenopathy exhibited both IgH and bcl-2 gene rearrangements. Three genotypic subsets of these ocular adnexal pseudolymphoma can be identified by the configuration of IgH gene and related oncogenes: with germline configuration of IgH gene and bcl-1, bcl-2 and c-myc oncogenes; with rearrangement of IgH gene but germline configuration of these oncogenes; and with recombination between rearranged IgH and bcl-1 genes. These results suggest in ocular adnexal pseudolymphoma a spectrum of clonal change evolving from polyclonal to monoclonal B-population, and further to monoclonal B-population with rearranged bcl-1, c-myc and/or bcl-2 oncogenes.

Adult↗
PubMed1991

Neurotoxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in the substantia nigra and the locus coeruleus in BALB/c mice.

The purpose of the present study was to determine whether 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), administered systemically or as a local infusion, has a direct neurotoxic action upon dopamine (DA) neurons in the substantia nigra (SN) and norepinephrine (NE) neurons in the locus coeruleus (LC) in BALB/c mice. Results indicated that both acute and repeated MPTP infusions (2 micrograms/0.3 microliter per side) significantly impaired locomotor activity, decreased stereotyped behavior and caused a disturbed pattern of locomotion in mice. The biochemical changes parallel the behavioral changes. Repeated MPTP infusions to the SN decreased DA levels markedly in the SN and the striatum; chronic MPTP infusions to the LC reduced NE levels markedly in the LC and the hippocampus. Furthermore, repeated MPTP injections for 7 days (30 mg/kg, one injection per day) have resulted in a long-lasting effect on both the nigral-striatal and the coeruleus-hippocampal systems. DA levels in the SN and the striatum were decreased at 1, 3, 7 and 28 days after the last MPTP injection. Similarly, NE levels in the LC and the hippocampus were also reduced markedly at the same time intervals examined. Behaviorally, repeated MPTP treatment also produced long-lasting motor deficits in mice at all time intervals studied. Moreover, the LC appeared to be more sensitive than the SN to the neurotoxic effects of MPTP. Immunohistochemical results have similarly revealed that repeated MPTP treatment markedly decreased tyrosine hydroxylase-positive cells and fibers in the SN and the LC. It also markedly decreased DA-beta-hydroxylase-positive cells and fibers in the LC.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1986

Oriental eyelids. Anatomic difference and surgical consideration.

Fashions change with time and beauty standards differ in different cultures. In recent years, there has been an increase in the number of immigrants to the United States from the Orient. The creation of an upper eyelid crease has been for the past several decades the most popular cosmetic procedure in many Asian countries. In order to perform this procedure to the satisfaction of an Oriental patient, the surgeon must know what the patient perceives as beautiful and the anatomic differences between the Oriental and the Occidental eyelids. In this paper with data collected from over 3,600 patients, we are presenting important statistics that enables the surgeon to understand better the Oriental mind and facilitate communications. The anatomic difference in the upper eyelid is also discussed.

Asian People↗
PubMedDate not supplied

Optic neuritis in herpes zoster ophthalmicus.

BACKGROUND: Optic neuritis in herpes zoster ophthalmicus (HZO) has been reported rarely. We report two cases of HZO optic neuritis with detailed magnetic resonance imaging study and treatment responses. CASES: One patient presented with anterior optic nerve involvement, and the second presented with retrobulbar optic neuritis. Contrast enhanced T(1)-weighted images were obtained in these 2 patients. Intravenous acyclovir and oral prednisolone were given simultaneously. OBSERVATIONS: Magnetic resonance imaging revealed peripheral enhancement of the optic nerve sheath complex on T(1)-weighted scan. Both patients recovered their vision within 3 months following the start of treatment. CONCLUSIONS: Magnetic resonance imaging is helpful for the diagnosis of HZO optic neuritis. Systemic acyclovir and steroid are effective in the treatment of HZO optic neuritis.

Acyclovir↗
PubMedDate not supplied

Elevated nitric oxide level in aqueous humor of patients with acute angle-closure glaucoma.

Nitric oxide, a noxious and free-radical gas, plays a key role in vasodilatation, inflammation, immunity, and neurotoxicity. Studies have shown that a recently detected NO synthase inducible isoform, found in astrocytes in the optic nerve heads of glaucoma patients, could stimulate excessive production of NO. The purpose of our study was to elucidate the role of NO production in the pathogenesis of glaucoma. We measured the concentrations of NO in aqueous humor from 11 patients with acute angle-closure glaucoma (AACG) and 14 patients with cataract. All samples were collected from patients who were free of any other systemic disease. Utilizing a chemiluminescence assay, we found that in AACG patients the NO levels in aqueous humor samples (83.2 +/- 6.7 microM) were significantly higher than in cataract patients (27.1 +/- 3.6 microM; p < 0.001). We therefore concluded that excessive NO in AACG patients reflects the degree of ocular impairment demonstrated by concomitant retinal cell and optic nerve cell damage.

Acute Disease↗