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Biomedical subjects

A Kan

Publications and source records attributed to A Kan.

At least 19 recordsLinked to original sources
PubMed2000

'An artefact gone awry': identification of the first case of nemaline myopathy by Dr R.D.K. Reye.

In 1963, Shy et al. (Brain 1963;86:793-810) and Conen et al. (Can Med Assoc J 1963;89:983-986) published the first description of a novel myopathy characterized by the aggregation of rods (nemaline bodies) in the muscle fibres. This disorder was subsequently known as nemaline myopathy. Dr Douglas Reye, an Australian pathologist, described a patient with 'rod myopathy' five years earlier, in 1958. Here we present Dr Reye's original description of nemaline myopathy, and details of the 'second opinion' which concluded that the rod were a 'processing artifact', so that the case was never published. Detailed histological and immunocytochemical studies of this original case demonstrate the typical features of nemaline myopathy, and a mutation in skeletal muscle alpha-actin has recently been identified in this patient. Not only was Dr Reye the first to use the term 'rod' in relation to muscle disease, he also made observations that are relevant to the pathogenesis of nemaline myopathy.

Australia↗
PubMed2000

The effect of dietary restriction and menstrual cycle on excess post-exercise oxygen consumption (EPOC) in young women.

The purpose of this study was to evaluate the effect of acute dietary restriction on excess post-exercise oxygen consumption (EPOC) in young women at two different phases of the menstrual cycle. Five young sedentary women (age 21-22 years) participated in this study. Each subject visited the laboratory eight times for measurement of EPOC. They performed cycle ergometer exercise for 60 min at a work rate corresponding to approximately 70% of VO2max under each four different conditions (i.e. standard diet/follicular phase (SF), standard diet/luteal phase (SL), restricted diet/follicular phase (RF) and restricted diet/luteal phase (RL)). The exercise was performed in the morning and VO2 was measured for the last 15 min of each hour for 7 h after the exercise. As a control, VO2 was also measured with an identical time schedule under the same four conditions but without exercise. EPOC was calculated as the difference of the VO2-time integral for 7 h between the exercise and control trial days in each of the four conditions (i.e. SL, SF, RL and RF). The diet was precisely controlled during 2 days (i.e. the test day and the day preceding it). The standard diet was 1600 kcal day-1 and the restricted diet was half of the standard diet. A two-way (dietary and menstrual cycle factors) ANOVA indicated that EPOC was significantly affected only by the dietary factor. The dietary restriction decreased EPOC compared to the standard dietary condition (SF 8.6 +/- 2.1, RF 5.3 +/- 1.6, SL 8.9 +/- 4.8, RL 4.0 +/- 1.2 l). These data indicate that for young sedentary women, EPOC is significantly lowered by prior acute dietary restriction but is not influenced by different phases of the menstrual cycle.

Adult↗
PubMed1999

Combined morphological and interphase fluorescence in situ hybridization study in multiple myeloma of Chinese patients.

To gain insight into the real incidence of the numeric chromosomal aberrations and the cell lineage involvement of the neoplastic process in multiple myeloma (MM), we examined 18 Chinese MM patients by May-Grunwald-Giemsa (MGG) staining and fluorescence in situ hybridization using three DNA centromeric probes specific for chromosomes 3, 7, and 9. In this investigation, cytogenetic abnormalities were detected in plasma cells (PCs), myeloid cells (MCs), and lymphoid cells (LCs) in all of the MM patients studied. This is the first demonstration of the cytogenetic aberration involved in the myeloid series. Furthermore, the MCs and PCs of 16 MM patients had the same aneuploidies in one or more of the chromosomes analyzed. These data suggest that the neoplastic transformation of MM may occur early in the hematopoietic development. Chromosomal aberrations involving mainly subclones and considerable cellular heterogeneity with gain of a variety of copy numbers of the same chromosome were demonstrated within PCs, which may possibly be the result of an underlying defect of PCs in the control of their number of chromosomes. Whereas PCs showed evidence suggestive of increased polyploidization, MCs and LCs, which exhibited similar chromosomal patterns as the former, rarely did. Thus, the clonal evolution from LC to PC, if that happens in MM, is characterized by chromosomal instability favoring growth of tumor cells with polysomies and polyploidies.

Adult↗
PubMed1999

Respiratory chain complex III [correction of complex] in deficiency with pruritus: a novel vitamin responsive clinical feature.

We report a child with an isolated complex III respiratory chain deficiency and global developmental delay who had severe pruritus with elevated plasma bile acid levels. A liver biopsy showed micronodular cirrhosis, and enzymologic evaluation demonstrated an isolated complex III deficiency in both liver and muscle. His pruritus improved and serum bile acid levels decreased after treatment with menadione and vitamin C.

Anemia, Iron-Deficiency↗
PubMed1997

Tl-201 positive, Ga-67 negative hepatoblastoma: a case report of a 12-year-old boy.

Hepatoblastoma is a primary liver neoplasm in which prompt diagnosis and resection are critical to long-term survival. Nuclear scintigraphy plays an important role in the characterization of hepatic masses. The authors present an unusual case of hepatoblastoma in a 12-year-old boy in whom Ga-67 scintigraphy and serum alpha-fetoprotein were negative. Positive Tl-201 scintigraphy pointed toward the true malignant nature of the mass and should be considered in the investigation of hepatic masses in childhood.

Biomarkers, Tumor↗
PubMed1997

Human papillomavirus and host variables as predictors of clinical course in patients with juvenile-onset recurrent respiratory papillomatosis.

This study provides the first systematic evaluation of papillomavirus type and viral mutation occurring during the course of juvenile-onset recurrent respiratory papillomatosis. One hundred ninety-nine consecutive papillomas excised from 47 children between 1981 and 1996 at The New Children's Hospital in Sydney, Australia, were tested for human papillomavirus (HPV) DNA by PCR. PCR products from the viral upstream regulatory region (URR) enhancer were sequenced, and variation was related to clinical variables. Forty-four of the 47 children had HPV-induced papillomas, with type 11 accounting for 24 (55%) and type 6 accounting for 19 (43%); one (2%) was positive for either type 6 or 11. Overall, 183 (98%) of the 186 samples with amplifiable DNA were HPV positive. There was no change in HPV type over time and no statistically significant association between HPV type and disease aggressiveness. One novel, large-scale URR duplication was identified in an HPV type 11 isolate in the last of a series of six papillomas examined and the first from the bronchus. However, the duplication was not found in HPV type 11 isolates from the associated pulmonary carcinoma and its metastases in other organs. Three of 14 URR point mutations coincided with transcription factor binding sites, but there were no obvious associations with clinical course. Chi-square and multiple linear regression analyses of clinicopathological variables revealed early age at diagnosis (less than 4 years) as an independent predictor of aggressive disease (P < 0.001). A bimodal distribution of the age at diagnosis was noted, with peaks at 2 and 11 years of age.

Adolescent↗
PubMed1995

Benign juvenile xanthogranuloma of the larynx.

Benign juvenile xanthogranuloma is a normolipaemic, self-limiting condition usually presenting with cutaneous, orbital or occasionally with visceral lesions. It is one type of histiocytosis, a term referring to a group of non-inflammatory, proliferative disorders of the monocyte/macrophage and dendritic cell systems [7]. We report a case of benign juvenile xanthogranuloma occurring in the larynx, a location not previously described.

Female↗
PubMed1995

Functional diffusive/convective interaction determining maximal oxygen uptake in humans: its modeling perspective.

In this short review, the frame of current understandings concerning what determines the upper limit of oxygen flow from the ambient air to the muscular mitochondria during maximal dynamic exercise in humans (i.e., VO2max), was summarized mainly from its modeling perspective. Several models and experimental evidences which appeared repeatedly in the recent debates regarding the factors limiting VO2max, were adopted and criticized. In conclusion, VO2max is determined in particular by the integrated interaction between the diffusive and convective factors both to lung O2-loading and muscular O2-unloading in the pathway for O2 flow, although all experimental observations cannot be satisfactorily explained at the present time.

Exercise↗
PubMed1994

Prenatal diagnosis and post-mortem study of a fetus with mosaic trisomy 14 due to a dic(14)(p11).

Amniocentesis at 17 weeks' gestation revealed a mosaic karyotype--46,XX/46,XX,-14,+dic(14)(p11). No abnormalities were detected on ultrasound. Growth and placentation were normal. The fetus was examined after termination of pregnancy and micrognathia and pulmonary hyperlobation were the only abnormalities detected. Several tissues were set up for cytogenetics, including fetal skin, kidney, ovary, and placenta. The diagnosis was confirmed by these studies. The level of mosaicism varied between tissues, with the trisomy 14 cell line highest in amniotic fluid.

Adult↗
PubMed1994

[Fetal circulation in relation to various maternal body positions].

To determine the possible effect of various maternal body position on feto-maternal circulation, we performed Doppler examinations on 50 women at different stages between the 27th and 40th week of normal pregnancy. Flow velocity waveforms of the umbilical artery, fetal descending aorta, and maternal uterine artery were recorded by pulsed Doppler scanner equipped with a 3.5MHz transducer (ALOKA SSD 680). The resistance index (RI) was calculated with the patient lying initially in the supine position, then 15 minutes later, in the lateral recumbent position. Maternal blood pressure, placental site, and fetal position were also assessed for possible relationship with the maternal position reflected by the resistance indices. The following results were obtained: (1) a negative correlation was observed between gestational period and umbilical artery flow velocity (r = -0.404, P < 0.05). (2) although up to the 37th week no outstanding difference was noted in the effect of maternal position on the flow velocity of the uterine and umbilical artery, from weeks 37 to 40, the resistance indices recorded in the supine position were significantly higher than those associated with the lateral recumbent position (P < 0.05). In the lateral recumbent position. Flow velocity of the umbilical artery was consistently in close correlation with that of the uterine artery. However maternal position had no bearing on the flow velocity in the fetal descending aorta; (3) no significant relationship was indicated between the flow velocity of the umbilical artery and blood pressure, placental site or fetal position.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Circulation↗
PubMed1993

Hemiplegia due to posterior cerebral artery occlusion.

BACKGROUND: Hemiplegia is a rare manifestation of posterior cerebral artery occlusion. The acute clinical picture may be difficult to differentiate from occlusion of the middle cerebral artery. A mechanism for the hemiplegia has not been conclusively determined. CASE DESCRIPTION: We describe a patient with hemiplegia secondary to posterior cerebral artery occlusion by an embolized fragment of a prosthetic valve. Computed tomographic scan showed the foreign body just distal to the origin of the posterior cerebral artery with infarction of its vascular territory. These findings were later confirmed at autopsy. There was no radiological or autopsy evidence of involvement of the other cerebral arteries or their territories. CONCLUSIONS: The patient provides further evidence that occlusion of the posterior cerebral artery just distal to its junction with the posterior communicating artery may produce contralateral hemiplegia without oculomotor nerve nucleus involvement.

Adolescent↗
PubMed1992

Rare malignant mid-femoral tumours in the first decade of life. Report of three cases with short literature review.

The most common femoral shaft tumours in children are eosinophilic granuloma and Ewing's sarcoma. Three children in the first decade of life with rare femoral shaft tumours are reported. There was one osteosarcoma and two chondrosarcomas. Radiographic differential diagnosis of the femoral shaft tumours and microscopic diagnostic difficulties of chondrosarcoma are discussed.

Age Factors↗
PubMed1991

Case report 684. Infantile myofibromatosis.

A 4-year-old boy presented with a mass in the left groin. Radiographic examination demonstrated that the soft-tissue mass contained calcification and was encroaching on the left femur. The pre-biopsy clinico-radiographic diagnosis was that of some sort of sarcoma. The pathological findings identified the mass as infantile myofibromatosis. This case serves to stress the need for greater caution in the clinico-radiographic diagnosis of soft-tissue tumors.

Child, Preschool↗
PubMed1990

Giant centrifugal miliaria profunda.

A 4-month-old developed rapidly enlarging, white plaques up to several centimeters in diameter in areas where occlusive tape had been applied, almost all on the sites of venous or arterial punctures. Microscopy demonstrated the features of miliaria profunda, with sweat duct occlusion and evidence of extravasation of sweat into the dermis. This clinical entity has not been described previously, and we suggest the name giant centrifugal miliaria profunda.

Humans↗
PubMed1990

[The regulation of B-lymphocyte activity by the Epstein-Barr virus in ankylosing spondylarthritis].

Former studies of the authors have indicated a deficit of the suppressor function of the T-lymphocytes on the activity of the B-lymphocytes by the Epstein-Barr Virus (EBV) in systemic autoimmune diseases: in 60% of the patients with rheumatoid arthritis, 50% of the patients with systemic sclerosis and 80% of the patients with systemic lupus erythematodes. Deficit of the specific cytotoxic function of the EBV in ankylosing spondylarthritis has been described. A study was carried out on 13 patients with ankylosing spondylarthritis and 13 healthy controls. All were immunized with EBV. Cultures were made experimentally. The secretion of IgM and IgG in the supernatant of the cultures was tested by ELISA. The T-suppression function of the specific T-lymphocytes of the EBV is not decreased in ankylosing spondylarthritis.

B-Lymphocytes↗
PubMed1989

Gastric heterotopia causing airway obstruction.

Two infants are reported each with a mass of heterotopic gastric tissue in the hypopharynx causing airway obstruction. Endoscopic laser removal of the tumours proved a satisfactory method of treatment. Gastric heterotopia in the head and neck region is rare but should be considered as a cause of stridor in infants.

Airway Obstruction↗