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Biomedical subjects

J H Choi

Publications and source records attributed to J H Choi.

At least 37 records · Page 2Linked to original sources
PubMed2004

Detection of fast neuronal signals in the motor cortex from functional near infrared spectroscopy measurements using independent component analysis.

Fast changes, in the range of milliseconds, in the optical properties of cerebral tissue are associated with brain activity and can be detected using non-invasive near-infrared spectroscopy (NIRS). These changes are assumed to be caused by changes in the light scattering properties of the neuronal tissue. The aim of this study was to develop highly sensitive data analysis algorithms to detect this fast signal, which is small compared with other physiological signals. A frequency-domain tissue oximeter, whose laser diodes were intensity modulated at 110 MHz, was used. The amplitude, mean intensity and phase of the modulated optical signal were measured at a sample rate of 96 Hz. The probe, consisting of four crossed source detector pairs was placed above the motor cortex, contralateral to the hand performing a tapping exercise consisting of alternating rest and tapping periods of 20 s each. An adaptive filter was used to remove the arterial pulsatility from the optical signals. Independent component analysis allowed further separation of a signal component containing the fast signal. In nine out of 14 subjects, a significant fast neuronal signal related to the finger tapping was found in the intensity signals. In the phase signals, indications of the fast signal were found in only two subjects.

Adult↗
PubMed2004

Clinicopathological features of incidental hepatocellular carcinoma in liver transplantation.

The incidence of detecting hepatocellular carcinoma (HCC) in a removed recipient liver after a liver transplant is not rare. The clinical features are expected to be different from the preoperatively diagnosed HCC. The aim of this study was to evaluate the clinicopathological features of incidental HCC. This study retrospectively analyzed five cases of incidental HCC among 51 liver transplant cases of HCC operated from September 1996 to February 2002. The proportion of an incidental HCC was 9.8%. The mean age was 46.2 years with a higher prevalence in may (80%, four cases). The alpha-fetoprotein level was normal or mildly elevated. HBsAg was positive in all cases. Imaging studies revealed regenerative or dysplastic nodules, or no specific lesion. The pathological findings demonstrated a mean size of 1.16 cm, multiplicity in three cases (60%), no microvascular invasion, and Edmonson grade I (60%) and II (40%). There was no recurrence of the HCC. However, two patients died due to an intracranial hemorrhage and a graft failure, respectively. In conclusion, incidentally found HCC showed less invasive pathological features and a better prognosis.

Carcinoma, Hepatocellular↗
PubMed2004

Large bowel obstruction caused by sclerosing peritonitis: contrast-enhanced CT findings.

Sclerosing peritonitis (SP) is a rare but serious complication of chronic ambulatory peritoneal dialysis (CAPD). SP is characterized by thickening of the peritoneum that encloses some or all of the small intestine. However, the early clinical features of SP are non-specific and are often not recognized until the patient develops complications. The most common complications of SP appear to be partial or complete small bowel obstruction, small bowel necrosis, and enterocutaneous fistulae, all of which, necessitate surgical intervention and have high mortality rates. Although the CT findings of SP are well recognized, to our knowledge, large bowel obstruction due to SP without peritoneal change have not been reported. We report a case of large bowel obstruction due to peritoneal sclerosis following long-term CAPD.

Colon, Ascending↗
PubMed2003

Primary clear cell sarcoma of bone.

Clear cell sarcoma is a rare soft tissue sarcoma of young adults with melanocytic differentiation. It occurs predominantly in the soft tissue of extremities, typically involving tendons and aponeuroses. Primary clear cell sarcoma of bone is extremely rare. We report a case of primary clear cell sarcoma of the right first metatarsal in a 48-year-old woman and provide a literature review of the entity.

Bone Neoplasms↗
PubMed2003

Indications of neutrino oscillation in a 250 km long-baseline experiment.

The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.

Journal Article↗
PubMed2003

A case of Trichosporon cutaneum folliculitis and septicaemia.

Trichosporon cutaneum, a saprophytic fungal organism normally found in the soil, has been increasingly recognized as a cause of life-threatening systemic illness in immunosuppressed patients including those with leukaemia. Cutaneous involvement occurs in about 30% of patients with T. cutaneum septicaemia although disseminated folliculitis has not been described to our knowledge. We now describe a case of T. cutaneum follicultis due to fungaemia in a neutropenic patient.

Adult↗
PubMed2003

Kikuchi-Fujimoto disease with papulopustular skin manifestations.

Kikuchi-Fujimoto disease commonly presents with cervical lymphadenopathy accompanied by fever, myalgia, neutropaenia, and rarely cutaneous eruption. Most cutaneous lesions present as erythematous macules, papules, plaques, nodules, or ulcers on the upper part of the body such as trunk, upper extremities, and face. We present a case of Kikuchi-Fujimoto disease with a papulopustular eruption on the whole body including the lower extremities.

Adult↗
PubMed2002

Dual ectopic thyroid.

Ectopic thyroid is an uncommon embryological aberration characterized by the presence of thyroid tissue in a site other than in its usual pre-tracheal region. It occurs along the path of descent of the developing thyroid primodium from the foramen cecum. It most commonly presents itself as a lingual thyroid and is the only thyroid in 70% of all cases. It is extremely rare for two ectopic foci of thyroid tissue to be present simultaneously. The authors report a recent case of dual ectopic thyroid present in the lingual and infrahyoid areas with no thyroid tissue in the pre-tracheal area in a 15-year-old girl. The patient had originally been scheduled for surgery under the impression of thyroglossal duct cyst; however, a pre-operative computed tomography scan of neck and thyroid scans revealed the presence of dual ectopic thyroid, thus preventing unnecessary surgery. Therefore, thyroid scan, along with either neck CT or neck ultrasonogram, should be performed routinely to avoid unnecessary surgery if the clinical picture is at all compatible with thyroid ectopia.

Adolescent↗
PubMed2002

CD30-positive T-cell-rich pseudolymphoma induced by gold acupuncture.

Cases of pseudolymphoma induced by intradermal gold injection or gold piercing have previously been described. Most of these cases showed the histopathological finding of B-lymphocyte predominant lymphocytoma cutis. We describe a patient with gold acupuncture-induced T-cell-rich pseudolymphoma. Some T cells showed positive staining with CD30. The lesions responded to an intralesional injection of triamcinolone acetonide.

Acupuncture Therapy↗
PubMed2002

Periungal hyperpigmentation induced by cisplatin.

A number of anticancer drugs are known to produce pigmentary changes affecting the skin or nails. Among them, cisplatin (cis-diamminedichloroplatinum)-induced hyperpigmentation has been described previously in only two cases. We describe an unusual case with hyperpigmentation confined to periungal areas of the hands and feet after treatment with cisplatin.

Aged↗
PubMed2002

Widespread skin-limited adult Langerhans cell histiocytosis: long-term follow-up with good response to interferon alpha.

Langerhans cell histiocytosis (LCH) most frequently involves bone, but also involves the skin in 40% of cases; in 10% of patients it is limited to the skin. Cutaneous findings of skin-limited LCH are scaly papules, vesicles, nodules, tumours with erosion, ulceration, or crusting and/or purpura. We report a case of widespread adult-onset LCH confined to skin in which topical carmustine, photochemotherapy, systemic steroids, and 2-chlorodeoxyadenosine were only partially effective. However, longer remission was achieved by the use of subcutaneous interferon-alpha2b.

Dermatologic Agents↗
PubMed2002

Cutaneous dissemination of nasal NK/T-cell lymphoma with bone marrow, liver and lung involvement.

We describe a 32-year-old Korean man with a primary nasal natural killer (NK)/T-cell lymphoma (NKTCL). Combination chemotherapy and radiotherapy resulted in initial complete remission. However, cutaneous dissemination to the trunk and proximal extremities occurred 16 months later and further investigations revealed involvement of the liver, lymph nodes, lung and bone marrow. Nasal CD56+ NKTCL is mostly localized to the nasal area but also shows a predilection for other sites, such as skin. Cutaneous dissemination may be an indicator of widespread metastasis to internal organs and is consistently fatal.

Adult↗
PubMed2002

Two cases of late onset Ota's naevus.

Ota's naevus is among the dermal melanocytoses that show a distinct pattern involving skin innervated by the trigeminal nerve. Most cases present at birth or manifest clinically in early childhood. Cases of acquired lesions in adult onset have been reported rarely. We present two cases of late onset Ota's naevus which were confirmed by skin biopsies. Both patients underwent Q-switched alexandrite laser treatment with a dose of 8.0 J/cm2 given four or five times at 6 weekly intervals and showed some improvement.

Adult↗
PubMed2002

Coexistence of CD30-positive anaplastic large cell lymphoma and mycosis fungoides.

Primary cutaneous T-cell lymphomas, including lymphomatoid papulosis, mycosis fungoides and CD30+ anaplastic large cell lymphoma (ALCL) overlap clinicopathologically and form part of a spectrum of lymphoproliferative disorders. There have been several case reports of these diseases coexisting. We describe a 59-year-old Korean man who presented with a recurrent, solitary CD30+ ALCL of 25 years' duration as well as patch stage mycosis fungoides of 11 years' duration. Such occurrences may represent different clinical manifestations of the same clonal T-cell abnormality, and provide further insight into the pathogenesis of these related disorders.

Humans↗