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Biomedical subjects

K P Chang

Publications and source records attributed to K P Chang.

At least 19 recordsLinked to original sources
PubMed2003

MEG localization of rolandic spikes with respect to SI and SII cortices in benign rolandic epilepsy.

The purpose of this study was to study the relationship between interictal spike sources and somatosensory cortices in benign rolandic epilepsy of childhood (BREC) using a whole-scalp neuromagnetometer. We recorded spontaneous magnetoencephalography (MEG) and EEG signals and cortical somatosensory-evoked magnetic fields (SEFs) to electric stimulation of the median nerve in 9 children with BREC. Interictal rolandic discharges (RDs) and SEFs were analyzed by equivalent current dipole (ECD) modeling. Based on the orientation and locations of corresponding ECDs, we compared generators of RDs with primary (SI) and second somatosensory cortices (SII). Our results showed that RDs and SII responses had similar ECD orientation on the magnetic field maps. The ECDs of RDs were localized 15.3 +/- 1.9 and 12.2 +/- 2.8 mm anterior to SI and SII, respectively. The spatial distance on average from the location of RDs to SII (21.9 +/- 1.6 mm) cortex was significantly shorter than to SI cortex (29.7 +/- 1.7 mm) (P<0.01, Wilcoxon signed-rank test). In conclusion, the cortical generators for RDs in patients with BREC are localized in the precentral motor cortex, closer to hand SII than to SI cortex.

Child↗
PubMed2003

Emergence of zoonotic canine leishmaniasis in the United States: isolation and immunohistochemical detection of Leishmania infantum from foxhounds from Virginia.

Previously considered an exotic disease, canine leishmaniasis caused by Leishmania infantum has recently been detected within the foxhound population in the United States and parts of Canada. Leishmania infantum is the etiologic agent of visceral leishmaniasis in many areas of the world and dogs are considered a major reservoir host for human Leishmania infections. Human visceral leishmaniasis has recently emerged as an opportunistic infection among individuals co-infected with HIV/AIDS and in persons taking immunosuppressive drugs. We report the isolation of L. infantum from 3 naturally infected foxhounds from Virginia by culture of popliteal lymph node and bone marrow, and the development of an immunohistochemical test to detect the parasite in tissues.

Animals↗
PubMed2003

Short report: distribution and feeding preference of the sand flies Phlebotomus sergenti and P. papatasi in a cutaneous leishmaniasis focus in Sanliurfa, Turkey.

Sand flies (Diptera: Psychodidae) and rodents were collected in the endemic focus of urban cutaneous leishmaniasis in Sanliurfa, Turkey. Phlebotomus sergenti and P. papatasi represented 99% of the sand fly population. These flies were trapped in highest numbers in animal sheds, followed by cellars. However, P. sergenti was relatively more abundant in rooms. An enzyme-linked immunosorbent assay of the gut contents from blood-fed females detected immunoglobulins specific to birds and mammals, suggesting that both species are opportunistic feeders, although poultry is a frequent blood source of P. sergenti. Blood sources include black rats (Rattus rattus) and house mice (Mus domesticus); these rodents are abundant inside houses, and might have a role in parasite circulation.

Animals↗
PubMed2002

Sand flies (Diptera: Phlebotominae) in Sanliurfa, Turkey: relationship of Phlebotomus sergenti with the epidemic of anthroponotic cutaneous leishmaniasis.

Sand fly (Diptera: Phlebotominae) fauna were surveyed in various districts of Sanliurfa in southeast Turkey for 3 yr immediately after an epidemic of cutaneous leishmaniasis (Leishmania tropica). Sticky papers and CDC light traps collected a total of 10,937 sand flies, of which 10,919 (4,158 females and 6,761 males) were identified as Phlebotomus and 18 (11 females and seven males) as Sergentomyia (S. theodori Parrot; S. adleri Theodor). Eight Phlebotomus spp. were identified: P. sergenti Parrot (72.3%), P. papatasi (Scopoli) (27.2%), P. brevis Theodor & Mesghali (0.20%), P. neglectus Leger & Pesson (0.13%), P. perfiliewi Parrot (0.05%), P. mascitti Grassi, P. halepensisTheodor, and P. alexandri Sinton (0.01%). Phlebotomus mascitti and P. neglectus, along with both Sergentomyia sp., have not been previously described from the study area. Similar results were obtained when both trapping methods were applied in the same houses, indicating that local P. sergenti and P. papatasi populations were equally attracted to the light. P. sergenti was consistently abundant, agreeing with the general view that this species is the vector of leishmaniasis in the region. There was no apparent decrease in the relative abundance of this vector versus the other species, suggesting that factor (s) other than a change in the dynamics of sand fly populations precipitated the decline of the human leishmaniasis epidemic in Sanliurfa.

Animals↗
PubMed2001

Seizure outcomes after anterior callosotomy in patients with posterior-dominant and with anterior-dominant epileptiform discharges.

OBJECTS: We wished to find whether there was any difference in the postoperative seizure outcome between patients with bisynchronous anterior-dominant and those with posterior-dominant EDs after anterior callosotomy. METHODS: Seizure outcomes after anterior callosotomy in 7 patients with bisynchronous posterior-dominant epileptiform discharges and in 54 patients with anterior-dominant seizures were compared. All 61 cases had been followed up for more than 2 years after operation. One patient (14.3%) had become seizure free. Two patients (28.6%) had more than 50% reduction in seizure frequency, but 4 patients (57.2%) showed no improvement at all. The percentage of cases with significant improvement (more than 50% reduction of seizure frequency) was 43% (3 in 7), which is lower than in the patients with bisynchronous anterior-dominant EDs (64.8%). CONCLUSIONS: Our preliminary results suggest that anterior partial callosotomy could still be helpful in cases with bisynchronous posterior-dominant epileptiform discharges but the prognosis may be less optimistic than for those with anteriorly located discharges.

Child↗
PubMed2001

Power spectrum analysis of heart rate variability in children with epilepsy.

OBJECT: Children with epilepsy have been found to be at increased risk of death during childhood. Sudden unexpected death (SUDEP) has accounted for at least 12% of deaths of children with epilepsy. The exact mechanisms of SUDEP are unknown; however, theories suggested have, to date, focused on autonomic instability. The purpose of this study was to investigate autonomic function in children with chronic epilepsy by means of power spectrum analysis of heart rate variability. METHODS: Thirty patients with epilepsy and 30 control subjects, all between the ages of 4 and 10 years, were enrolled in this study. Power spectrum analysis of heart rate variability (HRV) was performed under standardized conditions after the patients had rested for 15 min. Each patient was tested in a supine position first and then again in a head-up tilted position, with 15 min between the two tests. RESULTS: There was no significant difference between the low-frequency component (LF) and the high-frequency component (HF) of heart rate variability, or the LF/HF ratio, between the study and control groups, whether the test subjects were in the supine or the head-up tilt position. In the control group, however, the subjects showed a significantly greater LF component and a smaller HF component of heart rate variability, and a greater LF/HF ratio in the head-up position than in the supine position. This implies a normal sympathovagal balance. This phenomenon was not observed in the study group. This implies that the modulating effects on autonomic function deriving from the hemisphere were probably disturbed, owing to the brain lesions that each of the study group patients had already sustained. CONCLUSIONS: A disturbed balance of activity between the sympathetic and parasympathetic nervous system might result from the loss of hemispheric influence in patients with epilepsy. Nevertheless, further investigation is clearly necessary to ascertain the possible association of this disturbed balance with SUDEP. Further investigation is also needed to establish the exact location of the region in the brain that gives rise to this modulating influence.

Autonomic Nervous System Diseases↗
PubMed2001

An alternative dressing for skin graft immobilization: negative pressure dressing.

The key difficulty of skin grafting is keeping the graft immobilized on uneven surfaces involved with motion, such as the nuchal area, axilla, web spaces, and the perineal area. This study reports the development of a new idea of negative pressure dressing (NPD) to maintain good immobilization of the skin graft and, at the same time, not cause any significant distress in the patient's daily life. Furthermore, the components of this dressing are available in ordinary hospitals. In this report, there are eight cases of skin grafts which were applied by this method, and the average success rate was approximately 97%. Therefore, use of negative pressure dressings to safeguard immobilization of the skin graft is an appropriate alternative method for grafts on uneven or mobile surfaces.

Adolescent↗
PubMed2001

The nurse specialist role in Hong Kong: perceptions of nurse specialists, doctors and staff nurses.

AIM: The purpose of this study is to review and delineate the impact in terms of the perceived importance as well as the role components of nurse specialists in Hong Kong. RATIONALE: The Nurse Specialist Scheme was launched in 1994 in Hong Kong. Studies in the West showed that there were impacts on the roles of other members among the health care team. However, minimal local published work has been carried out in reviewing the scheme. DESIGN: The design of the study was nonexperimental. Data were collected by self-administered questionnaires. The questionnaire adopted was developed by O'Mullan (1995), and the five roles studied were administration, clinical practice, consultation, education and research. To ensure the contextual relevancy and consistency of the questionnaire, content validity and test-retest reliability tests were performed. The content validity index was 0.85 and the test-retest reliability (Spearman's rho coefficient) ranged from 0.57 to 0.97. Subjects were obtained by stratified convenience sampling technique. The ratios for subject selection among the doctors, ward managers, nursing officers and registered nurses were 3:1:3:10, respectively. Because of the small numbers for nurse specialists, they were all included in the study. The final sample consisted of 11 nurse specialists, 47 ward managers, 56 nursing officers, 110 registered nurses and 15 doctors (n=239). RESULTS: The results showed that there were significant differences in the perceptions of importance of the administration, clinical practice, education and research roles, and the frequency of occurrence of the clinical practice and research roles. This was further verified by the Fisher's Least Significant Differences (LSD) test. CONCLUSIONS: A regulatory system of the nurse specialist was recommended to monitor the development of the nurse specialist role and practice and to ensure the safety of the public with regard to the emerging role. Both the implications and limitations are discussed.

Attitude of Health Personnel↗
PubMed2001

Endoscopic excision of benign tumors in the forehead and brow.

Twenty-five cases of benign tumor of the forehead and brow were excised successfully with endoscope-assisted surgery. The access incision was selected strategically behind the front hairline. For tumors in the middle of the forehead, the tumor was approached by subgaleal dissection. For those in the brow or temporal area, the dissection plane was just superficial to the deep temporal fascia. Patient age ranged from 3 to 59 years. The mass varied in size from 1.0 x 0.5 to 2.0 x 2.0 cm. There were 18 lipomas, 6 dermoid cysts, and 1 pilomatricoma. There was no residual mass or recurrence 1 to 24 months postoperatively. There was no paresthesia or numbness in the scalp. Patients and their families were greatly satisfied with this operation and the absence of visible scarring.

Adolescent↗
PubMed2001

Measurement of the volume of the pedicled TRAM flap in immediate breast reconstruction.

The transverse rectus abdominis musculocutaneous (TRAM) flap is now accepted as the standard for breast reconstruction, but achieving symmetrical breast reconstruction is still a challenge. A precise estimate of the volume of the flap is necessary to reconstruct a symmetrical and aesthetically pleasing breast. Many methods have been developed to overcome this problem, but they have not been suitable for the pedicled TRAM flap. By using a self-made device based on the Archimedes' principle, the authors can calculate accurately the volume of the pedicled TRAM flap and predict reliably the breast volume intraoperatively. The "procedure" is based on a self-made box into which the pedicled TRAM flap is placed. Warm saline is added to the box and the flap is then removed. Flap volume is calculated easily by determining the difference between the preestimated volume of the box and the volume of the residual water. From February to May 2000, this method was used on 28 patients to predict breast volume for breast reconstruction. This study revealed that the difference of the maximal chest circumferences (the index of the breast volume) demonstrates a positive correlation with the difference of the volumes and weights between the mastectomy specimen and the net TRAM flap. However, a more closely positive correlation exists between the differences of maximal chest circumference volume (r = 0.677) than maximal chest circumference weight (r = 0.618). These data reveal that the reconstructed breast's volume has a closer relationship with the volume of the net pedicled TRAM flap, rather than with its weight.

Adult↗
PubMed2001

Differentiation of recurrent nasopharyngeal carcinoma and skull base osteoradionecrosis by Epstein-Barr virus-derived latent membrane protein-1 gene.

OBJECTIVES: In patients with nasopharyngeal carcinoma (NPC), the differentiation between recurrent primary cancer and osteoradionecrosis (ORN) is clinically difficult. Epstein-Barr virus (EBV)-derived latent membrane protein-1 (LMP-1) has been demonstrated to be highly associated with NPC. The objective of this study is to define the role of the LMP-1 gene in the differential diagnosis of recurrent NPC and ORN. STUDY DESIGN: Prospective. METHODS: From July 1998 to June 2000, 15 postirradiated patients with NPC who were initially diagnosed to have skull base ORN underwent endoscopic sequestrectomy. The sequestra were examined for the presence of the LMP-1 gene and cancer. RESULTS: Two of 15 patients had recurrent cancer and only these two patients demonstrated a positive LMP-1 gene in their surgically removed sequestra. The presence of the LMP-1 gene in the sequestrum coincided with biopsy-proven local recurrence. CONCLUSIONS: The LMP-1 gene is a potential marker to differentiate between recurrent NPC and ORN. The presence of the LMP-1 gene in patients with ORN may indicate local recurrence.

Diagnosis, Differential↗
PubMed2001

Predictors of maternal depression for families having a child with epilepsy.

The purpose of this study was to use a descriptive correlational design to examine the relationship among maternal uncertainty, boundary ambiguity and depression in families having a child with epilepsy. Three hundred and twenty-four mothers from the child epilepsy day-clinics of three teaching hospitals in Taiwan participated in this study. Data collection was performed by well-trained research assistants who helped mothers fill out the well-developed Chinese version of the Parental Perception of Uncertainty Scale, the Boundary Ambiguity scale, and the Beck Depression Inventory. Uncertainty was positively associated with boundary ambiguity and depression. Boundary ambiguity was positively associated with depression. Stepwise regression analysis demonstrated that boundary ambiguity, uncertainty and mother's age are predictors of a mother's depression which account for 21.49% of the total variance of depression. The results provide a scientific knowledge base for nursing interventions that aim to provide clear information about the child's illness and help to establish appropriate patterns of parent-child interaction in terms of maintaining family boundary integrity and mothers' functional adaptability.

Adolescent↗
PubMed2000

Seizure outcome after corpus callosotomy: the Taiwan experience.

From September 1989 to August 1996, we performed anterior corpus callosotomy in 83 patients. Unfortunately, 9 patients were lost to follow-up. Among the remaining 74 patients, 59 had Lennox-Gastaut syndrome (evolved from infantile spasms in 22), 9 had complex partial seizures with or without secondary generalized seizures, 1 had multifocal independent epileptogenic foci (MISF) syndrome, 3 had hemiconvulsion-hemiplegia-epilepsy (HHE), and 2 had infantile spasms. All cases were followed up for at least 2 years after surgery. The highest rate of significant improvement (more than 50% reduction in seizure frequency) was noted in the patients with generalized tonic-clonic seizures, 82.1% of whom experienced significant improvement, followed by those with generalized tonic seizures (76. 7%), atonic seizures (72.7%), myoclonic seizures (64.9%), atypical absences (58.6%), and complex partial seizure with or without secondary generalization (61.5%). Complete freedom from seizures was noted in 14 cases (18.9%). One patient had the anterior half of his right palm amputated following radial artery thrombosis complicated by insertion of an arterial line during anesthesia. Otherwise, there were no major postoperative complications except for brief mutism and multifocal jerks in some patients during the 1st postoperative week. Thus, we conclude that corpus callosotomy is a safe alternative treatment for all kinds of medically intractable seizures, especially generalized epilepsy.

Adolescent↗
PubMed2000

Endoscope-assisted correction of primary varicose veins.

The purpose of this study is to evaluate the possibilities and results of application of endoscopic surgery in the operation of primary varicose veins. With good illumination and magnified viewing, the varicosities, incompetent perforating veins, and healthy veins were clearly visualized. The incompetent perforating veins were clipped and divided securely. The varicose veins and tributaries were dissected and removed completely after being clipped and divided. The healthy veins were preserved if possible. Primary varicose veins in 43 limbs of 37 patients were operated. The operation was conducted through one access incision in 31 limbs (72%), two incisions in 11 limbs (25%), and three incisions in 1 limb. The mean number of incisions was 1.3 in each limb. Hematoma formation occurred in 1 patient due to the slipping of one clip on the third postoperative day. The other patients had uneventful postoperative courses. All 37 patients were reviewed 4 to 30 months postoperatively. Only one limb had recurrent varices at a new site. Ninety-seven percent of limbs (42 of 43) had no recurrence of varicose veins. Seventy-eight percent of patients (29 of 37) were extremely pleased with this operation. Although the other 22% of patients (8 of 37) appreciated this operation, they were not completely satisfied because some preoperative complaints persisted. In this series, the recurrent rate of varicose veins was low (1 in 43 limbs) and postoperative scarring was minimized, in addition to the advantages of endoscopic surgery. These results demonstrate that endoscopic surgery is a worthy alternative procedure for correcting primary varicose veins.

Adult↗
PubMed2000

Endoscope-assisted parotidectomy for benign parotid tumors.

Sixteen cases of parotidectomy of benign tumors were performed by means of a short incision with the assistance of endoscopic surgery. The average length of the preauricular and retromandibular incision was 6.9 cm (range, 6.0-8.1 cm). This incision provided safe dissection of the facial nerve trunk and exposed a major part of the gland to direct vision. Identification and separation of the facial nerve branches in peripheral glandular tissue was performed by means of endoscopic surgery instead of wide exposure with a long incision. Because endoscopic surgery provided good illumination and magnification on the monitor, the operation could proceed clearly and sharply in a bloodless field. Therefore, the incidence of facial nerve injury and perioperative morbidity was minimized. In this series, tumors were removed completely, without injury to the facial nerve. Patients were also satisfied with the short and inconspicuous postoperative scars.

Adult↗
PubMed2000

Endoscopic management of skull base osteoradionecrosis.

OBJECTIVE: Osteoradionecrosis is one of the most serious complications in radiotherapy of nasopharyngeal carcinoma. We describe a new endoscopic approach to resolve resultant skull base osteoradionecrosis. The objective of this study is to evaluate the efficacy of endoscopic management of skull base osteoradionecrosis. STUDY DESIGN: A prospective study of the outcome of endoscopic management for patients with skull base osteoradionecrosis. METHODS: Between 1994 and 1998 six patients who had irradiation previously for nasopharyngeal carcinoma had skull base osteoradionecrosis. A sinoscopic approach was applied for diagnosis and sequestrectomy. This diagnosis was based on the criterion of exposed necrotic bone after removing all crust in the nasopharynx and further confirmed on pathological examination after sequestrectomy. Effective cure was defined as intact mucosal coverage without any ulcer or exposed necrotic bone observed in the nasopharynx and the absence of antecedent accompanying symptoms after management. RESULTS: Six patients (10%) were symptom free. Five (83.3%) patients had effective cure. There was no surgical morbidity or mortality. CONCLUSION: Endoscopic sequestrectomy is a justified approach to skull base osteoradionecrosis.

Adult↗