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Biomedical subjects

H S Chan

Publications and source records attributed to H S Chan.

At least 127 records · Page 7Linked to original sources
PubMed1987

Comparative evaluation of benzydamine oral rinse in children with antineoplastic-induced stomatitis.

This nonblinded, crossover study was undertaken to compare the extent and duration of analgesia after administration of benzydamine 0.15% oral rinse and Hospital for Sick Children (HSC) mouthwash for pain (nystatin 7000 U/ml, lidocaine viscous 0.58 ml/ml in NaCl 0.9%) in pediatric patients with antineoplastic-induced stomatitis. Each mouthwash was administered as a paint or a gargle q2h while the child was awake on two consecutive days. Patients older than three years were asked to describe their pain by means of a pictorial or a visual analog scale. Pain was assessed by the investigator, parent, or nurse caring for the patient as well as the patient whenever possible before each dose and 10, 30, and 60 minutes after the first three doses each day for four days. Stomatitis severity was graded daily. Four patients completed the study protocol; an additional three patients dropped out of the study due to severe stinging when benzydamine oral rinse was administered. The case histories of the patients who completed the study are presented. Both preparations reduced pain for at least one hour in most instances but not for two hours. Three of four patients elected to continue treatment with HSC mouthwash for pain. Study recruitment was halted due to the ethical concern of continuing with the knowledge that benzydamine oral rinse causes oral pain and stinging, especially in patients with severe stomatitis.

Adolescent↗
PubMed1987

The value of intensive combination chemotherapy for juvenile chronic myelogenous leukemia.

Nine children with juvenile chronic myelogenous leukemia (JCML) were diagnosed in an 8-year period from 1977 to 1984. The clinical courses and outcomes of five patients who received minimal or no chemotherapy were compared with that of four patients who were treated with intensive acute nonlymphoblastic leukemia (ANLL) combination chemotherapy. None of the five patients in the former group achieved clinical remission and their survivals were 1, 4, 4, 7, and 29 months, respectively. All four patients in the latter group achieved clinical remissions that lasted 11, 21, 21, and 27 + months, respectively. The durations of their survival (21, 26, 30, and 32 + months) were significantly better than the five patients who received minimal or no chemotherapy (P less than .05). Despite hospitalizations for chemotherapy and for treatment of chemotherapy-associated complications, the clinical status and quality of life of the children who achieved clinical remission were superior to those who remained in relapse. Although intensive chemotherapy induced lengthy remissions, three of the four patients have relapsed. Cytogenetic and cell culture data indicated that the monocytic-macrophage cells characteristic of JCML appeared to be suppressed during remission rather than totally eliminated. We recommend that ANLL-type combination chemotherapy be used as the initial treatment of JCML because of its promptness in effecting clinical remissions. Improved maintenance and consolidation protocols have to be developed to produce durable remissions and cures. Alternatively, bone marrow transplantation may be a useful option soon after remission is achieved with chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Nabilone versus prochlorperazine for control of cancer chemotherapy-induced emesis in children: a double-blind, crossover trial.

In a randomized, double-blind, crossover trial, nabilone was compared to prochlorperazine for control of cancer chemotherapy-induced emesis in 30 children 3.5 to 17.8 years of age. All subjects received two consecutive identical cycles of chemotherapy with the trial antiemetics given in accordance to a body weight-based dosage schedule beginning eight to 12 hours before treatment. The overall rate of improvement of retching and emesis was 70% during the nabilone and 30% during the prochlorperazine treatment cycles (P = .003, chi 2 test). On completion of the trial, 66% of the children stated that they preferred nabilone, 17% preferred prochlorperazine, and 17% had no preference (P = .015, chi 2 test). Major side effects (dizziness, drowsiness, and mood alteration) were more common (11% v 3%) during the nabilone treatment cycles. CNS side effects appeared to be dose related and were most likely to occur when the nabilone dosage exceeded 60 micrograms/kg/d, but individual tolerance to nabilone varied considerably. Lower dosages of nabilone were associated with equivalent efficacy and no major side effects. Nabilone appears to be a safe, effective, and well-tolerated antiemetic drug for children receiving cancer chemotherapy. Although major side effects may occur at higher dosages, nabilone is preferable to prochlorperazine because of improved efficacy.

Adolescent↗
PubMed1987

Residual juvenile chronic myelogenous leukemia cells detected in peripheral blood during clinical remission.

At diagnosis peripheral blood (PB) or bone marrow from patients with juvenile chronic myelogenous leukemia (JCML) have shown two reproducible abnormalities when studied in cell culture: impaired growth of normal hematopoietic progenitors and excessive proliferation of malignant monocyte-macrophage elements. We used these findings to assess quality of treatment response by serially studying PB specimens from four JCML patients (patients 5, 7, 8, and 9) in complete chemotherapy-induced remission. PB readily yielded high numbers of monocyte-macrophage colonies in CFU-C and CFU-GEMM assays when cultured in early remission, and the colonies were cytogenetically proven to have arisen from a malignant clone in patient 9. When studied later in remission, the abnormal cell proliferation persisted in three of the four patients, but in patient 8 PB colony growth resembled controls. Similarly, when PB from patient 8 was studied in liquid culture without using added growth factor, cell proliferation declined identical to controls, whereas PB from the other three patients showed exuberant growth of monocyte-macrophage elements. Patient 8 successfully completed therapy and has been in a long-term, disease-free remission. The other three had recurrent, ultimately fatal disease. The cell cultures have allowed detection of residual abnormal cells that circulate in PB of JCML patients in remission. Although patient numbers were small because of the rarity of JCML, the data suggested that persistence of leukemia cells in these patients had a bearing on clinical outcome.

Antigens, Surface↗
PubMed1986

Childhood erythroleukemia. Studies on pathogenesis using colony assays.

Marrow hematopoiesis was examined in two infants with erythroleukemia (EL) using cell culture colony assays. At diagnosis, marrow from both yielded normal to increased numbers of granulocytic colonies (CFU-C), erythroid bursts (BFU-E), and mixed colonies (CFU-GEMM), which contrasted sharply with the reduced growth in eight other newly diagnosed patients with acute leukemia. BFU-E proliferation and hemoglobinization proceeded normally in culture and was entirely erythropoietin-dependent. CFU-C colony cellular composition showed normal granulopoiesis in various stages of development. Despite low numbers of morphologically recognizable blasts in the aspirates, they were readily identified in a blast colony assay because of their high plating efficiency and high index of self-renewal on replating. Blast cells in all cultures had myeloblastic morphology, were peroxidase positive, and expressed the granulocytic-specific My-1 antigen. Monosomy 7 was seen in fresh and cultured blast cells but not in lymphocytes, indicating a clonal proliferation. After chemotherapy-induced remission, blast colonies and monosomy 7 could no longer be detected. It appears that the integrity and function of the normal hematopoietic progenitor pool were preserved in these patients with EL. The abnormal myeloblastic proliferation was expressed actively in colony assays and was useful diagnostically in these cases because marrow morphology was nondiagnostic. In these patients, EL seems to be a misnomer since the findings are suggestive of acute myeloblastic leukemia with secondary erythroid and granulocytic hyperplasia.

Bone Marrow↗
PubMed1986

Characterization of malignant peripheral blood cells of juvenile chronic myelogenous leukemia.

Characterization studies were performed on the malignant peripheral blood cells from three patients with juvenile chronic myelogenous leukemia (JCML) by allowing the cells to increase numerically in liquid cultures. JCML cells proliferated rapidly and excessively in the absence of an added humoral growth factor, whereas control peripheral blood cells declined in number when cultured under identical conditions. Clonality of JCML cells was proven by cytogenetic analysis of the proliferating population. JCML cells were exclusively of monocytic lineage as determined by morphology, staining characteristics, and monoclonal antibody identification of cell-specific surface antigens, but cytochemical and functional studies identified aberrant properties indicating defective differentiation. Striking differences from control cells in ultrastructure and topography were also observed by transmission and scanning electron microscopy. These data provide new information on the cellular origin of JCML and form the basis for further study of leukemic cell biology in this disease.

Child, Preschool↗
PubMed1986

Juvenile chronic myelogenous leukemia: characterization of the disease using cell cultures.

To characterize juvenile chronic myelogenous leukemia (JCML), the proliferative properties of bone marrow (BM) and peripheral blood (PB) cells from nine patients were studied using assays for CFU-C and CFU-GEMM and liquid cultures. All specimens showed two reproducible abnormalities: impaired growth of normal hematopoietic progenitors and excessive proliferation of monocyte-macrophage colonies in the absence of exogenous colony-stimulating activity (CSA). Cytogenetic studies in one patient indicated that the CFU-C were malignant because BM cells at diagnosis and monocyte-macrophage colonies showed an abnormal karyotype, whereas PB lymphocytes did not. In contrast to JCML, PB from six adults with Philadelphia (Ph1) chromosome-positive chronic myelogenous leukemia (Ph1 + CML) yielded CSA-dependent CFU-C colonies which were composed of granulocytes, macrophages, or both, as well as exuberant growth of BFU-E colonies. Co-cultures of JCML BM adherent or nonadherent cells with normal BM resulted in suppression of normal hematopoietic colony formation. Supernatant from JCML adherent cells in liquid culture or plasma from newly diagnosed untreated JCML patients also suppressed control BM colony growth in a dose-dependent manner. These findings confirm that JCML is a malignant disorder of monocytic lineage and suggest that the mechanism of hematopoietic failure in JCML is mediated by an inhibitory monokine secreted by malignant JCML cells.

Bone Marrow Cells↗
PubMed1985

Primary and secondary tumors of childhood involving the heart, pericardium, and great vessels. A report of 75 cases and review of the literature.

Between 1919 and 1981, 16 children with primary cardiac tumors (8 rhabdomyomas, 5 fibromas, 2 myxomas, and 1 rhabdomyosarcoma) and 59 children with secondary tumors of the cardiovascular system were seen at The Hospital for Sick Children in Toronto. Distant metastases in 45 children of the latter group, in descending order of frequency, were from non-Hodgkin's lymphoma, neuroblastoma, soft tissue and bone sarcoma, Wilms' tumor, and hepatoma, and involved the myocardium and pericardium. In the remaining 14 children, tumor thrombi from Wilms' tumor (9 cases), adrenal (2 cases) and hepatocellular carcinoma (2 cases), and endodermal sinus tumor (1 case) extended directly into the great veins and/or cardiac chambers. Children with primary and secondary tumors often present with nonspecific clinical, plain radiographic, electrocardiographic, and M-mode echocardiographic findings. Early recognition, utilizing special diagnostic procedures such as two-dimensional echocardiography, computerized axial tomography, angiocardiography, and inferior venocavography, followed by elective surgical resection of tumor under cardiopulmonary bypass and/or radiation and chemotherapy, offers patients with cardiovascular tumors the best chance of cure.

Angiocardiography↗
PubMed1985

Mapping the binocular visual field for a target embedded in a regular background.

The binocular functional visual-field, which is the area around the fixation point within which a target can be detected, was mapped, for two subjects, using a peripherally presented target in a regular background. The field boundaries were very irregular, there were regions of insensitivity within the field areas, and there were differences between the subjects. It was suggested that the irregular boundary and areas of insensitivity may have important implications for mathematical models of visual search. Individual visual-field characteristics may partly account for the difficulty experienced by some people in locating targets even after repeated scanning.

Adult↗
PubMed1984

Extracranial metastases in childhood primary intracranial tumors. A report of 21 cases and review of the literature.

A clinical and pathologic review of primary intracranial tumors (917 cases in a 62-year period) at The Hospital for Sick Children, Toronto, identified 21 cases with systemic metastases (2.3%). This included 15 cases of medulloblastoma and 1 case each of astrocytoma, meningeal sarcoma, malignant melanoma, ependymoblastoma, teratoma, and endodermal sinus tumor, adding to the pediatric literature of 94 previously reported cases (72 medulloblastoma and 22 cases of other brain tumors). Like adults, children with medulloblastoma tend to develop bone and bone marrow metastases, while those with other brain tumors frequently invade adjacent tissues, and then spread to regional lymph nodes and the lungs. The prognosis is almost uniformly fatal, although prolonged palliation could be achieved with radiation and/or chemotherapy. The pathogenesis of systemic metastases is related to breakage of the blood-brain barrier, whether at surgery, or with tumor invasion into vascular channels, and especially with preoperative systemic-cerebrospinal fluid shunting. Thirteen of 16 patients who developed systemic metastases, including 5 with peritoneal involvement, had ineffective or no millipore filters within their shunts, suggesting their possible prophylactic role against tumor dissemination. A greater understanding of the pathogenesis of systemic metastases may aid the design of future effective preventive measures.

Adolescent↗
PubMed1984

A rare cause of spinal cord compression in childhood from intraspinal mesenchymal chondrosarcoma. A report of two cases and review of the literature.

Two children presented with acute spinal cord compression by primary and metastatic intraspinal mesenchymal chondrosarcoma, a rare pediatric malignancy. Patients with the primary intraspinal tumor usually present early and often respond well to combined surgery, irradiation and chemotherapy. Patients with intraspinal metastases present late in the course of their disease and their prognoses are poor.

Adolescent↗
PubMed1984

Pheochromocytoma in childhood: the important role of computed tomography in tumour localization.

The radiographic features of five children with nine pheochromocytomas are reviewed. Seven of eight lesions studied by CT were accurately localized. One 1.5 cm diameter extra-adrenal lesion, studied with a 2-min scanner, was not detected. Angiography failed to detect two of seven lesions. Fast scan and high resolution CT of the entire abdomen and pelvis is recommended as the initial modality of choice in children suspected of having pheochromocytoma. Chest CT need only be performed if a lesion is suspected on a chest radiograph or if the abdominal and pelvic CT reveal no lesion.

Adolescent↗
PubMed1984

Ocular involvement in neuroblastoma: prognostic implications.

Neuroblastoma is one of the commonest childhood malignancies. The most important prognostic factor is age at diagnosis; early diagnosis, when the tumor is still localized and surgically resectable, is second in importance. On retrospective review of children seen at the Hospital for Sick Children, ophthalmic involvement was seen in 80 of 405 (20%). The three major eye signs of neuroblastoma, proptosis, Horner's syndrome and opsoclonus, are closely related to the site, stage of tumor, and outcome of the patient. Proptosis or periorbital ecchymosis due to orbital metastases was present in 60 of 80 children (bilaterally in 33). The 3-year survival rate was 11.2%. In 53 of 60 cases with orbital metastases the neuroblastoma originated in the abdomen. Unilateral Horner's syndrome occurred in 14 children, as the presenting sign in 9, related to localized disease in 11 and in a favorable location (cervical or thoracic neuroblastoma) in 8. The 3-year survival rate was 78.6%. Opsoclonus-myoclonus was the presenting sign of occult, localized neuroblastoma in all 9 children in whom it occurred. The 3-year survival rate was 100%. For all presentations, girls had a significantly better survival rate than boys (48.7% vs. 22.4%). Children presenting with any of these ophthalmological signs should undergo thorough and repeated investigations searching for neuroblastoma.

Child, Preschool↗
PubMed1984

Myxopapillary ependymoma of the filum terminale and cauda equina in childhood: report of seven cases and review of the literature.

Seven of fourteen children with spinal cord ependymoma had myxopapillary tumors of the filum terminale. These tumors made up 15.9% of all primary spinal neuroectodermal tumors in children (44 cases) seen during a 62-year period (1919 to 1981). Their clinical presentation, radiological features, pathological findings, treatment, and outcome are reported. Six of the seven patients were known to be alive at the time of writing. The seventh patient was lost to follow-up after 3 years without tumor recurrence. Of 5 patients whose primary mode of treatment was operation alone. 3 had intraspinal or intracranial recurrences. Despite tumor recurrences, 2 patients were long term survivors after further operation and irradiation, whereas the third patient recently received craniospinal irradiation for intracranial tumor recurrence. The 2 patients who did not have tumor recurrence after operation alone had been followed for 3 and 7 years, respectively. Two children with subtotal tumor resection and spinal irradiation had no recurrences at 1 and 17 years, respectively. Our data suggest that this unusual subtype of spinal ependymoma is not uncommon during childhood and has a good prognosis. All patients with this tumor require prolonged follow-up for tumor recurrence after operation and irradiation.

Adolescent↗
PubMed1984

Primary intracranial choriocarcinoma: a report of two cases and a review of the literature.

Among 848 cases of primary intracranial malignancy seen during a 63-year period at a pediatric hospital, there were 2 cases of primary pineal choriocarcinoma. The clinical and laboratory findings of these 2 cases were similar to those of 33 cases of intracranial choriocarcinoma reported in the literature. In 1 patient with precocious puberty, the diagnosis was confirmed by labeling human chorionic gonadotropin (HCG) within the tumor, which had been stored for 25 years. In the other patient, who is alive and well 18 months after diagnosis, the response to cranial irradiation and intensive chemotherapy was monitored with serial measurements of serum, cerebrospinal fluid, and urinary HCG and with computed tomography. We conclude that intensive chemotherapy, radiation, and tumor resection, if feasible, offer the best chance of curing this otherwise fatal disease.

Adolescent↗