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Background: The doubly labelled water (DLW) method is the technique of choice for measurement of free-living total energy expenditure (TEE) in humans. A major constraint on the clinical applicability of the method has been the expense of the (18)O isotope., Method: We have used a reduced-dose (one-tenth of the currently recommended standard dose) of DLW for the measurement of TEE and body composition in nine healthy adult male volunteers., Results: TEE measured by reduced-dose DLW was positively correlated with resting energy expenditure measured by metabolic cart (r=0.87, P<0.01). Isotope-derived fat mass and body mass index were strongly correlated (r=0.86, P<0.01). In four subjects in whom we performed a complementary evaluation using standard-dose isotope enrichment, the TEE measurements were satisfactorily comparable (mean+/-s.d.: reduced dose 2586+/-155 kcal/day vs standard dose 2843+/-321 kcal/day; mean difference 257+/-265 kcal/day)., Conclusion: These data indicate that DLW measurements of human energy expenditure and body composition can be performed at a substantially reduced dose (and cost) of isotope enrichment than is currently employed.

In the history of electrocardiography the names of two physiologists stand out: Augustus Waller (1865-1922) and Willem Einthoven (1860-1927). Waller was the first to show that the beating heart produces a weak electric potential, which can be registered by a measuring device connected to electrodes attached to the skin. Einthoven developed a 'string' galvanometer, which was much faster and more sensitive than the system used by Waller. Einthoven's electrocardiograph was ready for use in 1903. To facilitate investigations of patients Einthoven connected his instrument to the Academic Hospital in Leyden, by a telephone line, as suggested by his engineering colleague Johannes Bosscha in Delft. The first successful tele-electrocardiogram was transmitted on Sunday 22 March 1905. The heart tones were registered by wiring a specially developed microphone placed on the subject's chest to another string galvanometer. The event was therefore a first both for tele-electrocardiography and for telephonocardiography. We are still awaiting the full-scale implementation of these achievements, 100 years later.

Telemedicine is a vast subject, but as yet there are limited data on the clinical effectiveness and cost-effectiveness of most telemedicine applications. As a result, objective information about the benefits and drawbacks of telemedicine is limited. This review is therefore based mainly on preliminary results, opinions and predictions. Many potential benefits of telemedicine can be envisaged, including: improved access to information; provision of care not previously deliverable; improved access to services and increasing care delivery; improved professional education; quality control of screening programmes; and reduced health-care costs. Although telemedicine clearly has a wide range of potential benefits, it also has some disadvantages. The main ones that can be envisaged are: a breakdown in the relationship between health professional and patient; a breakdown in the relationship between health professionals; issues concerning the quality of health information; and organizational and bureaucratic difficulties. On balance, the benefits of telemedicine are substantial, assuming that more research will reduce or eliminate the obvious drawbacks.

Value norms within an interactive social network, social capital, can improve many aspects of the quality of life including health. Effective means of communication are key to making the social capital available. Telemedicine is therefore well placed to playing an important role in providing social capital to many groups in a society, which are at present deprived of this resource for maintaining health.

The planning and installation of a telemedicine system for communication within a teaching hospital and its academic and hospital units with a capacity for accommodation of up to 400 video-stations is described. The system is intended for improving the communication between patients and health professionals, and between the health professionals themselves. It also provides the basis for improving pre-graduate teaching, especially problem-based learning, and all aspects of postgraduate teaching.

Objective: To elucidate the metabolic changes occurring within hepatocytes during acute phase reaction and liver regeneration., Summary Background Data: The metabolic events occurring within the liver during the hepatic stress response are poorly understood. The authors used in vivo 31-phosphorus magnetic resonance spectroscopy to study hepatic metabolism after surgical trauma with and without loss of liver cell mass., Methods: Three groups were studied: five patients undergoing partial hepatectomy; five patients in whom laparotomy and colonic resection was performed; and five patients treated by thyroidectomy. Hepatic metabolism was evaluated by 31-phosphorus magnetic resonance spectroscopy before surgery and serially thereafter on postoperative days 2, 4, 6, 14, and 28. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points., Results: The authors found that alterations in hepatocyte phospholipid metabolism occurred after surgery that were correlated with changes in circulating acute phase proteins. Liver regeneration after hepatectomy was also associated with a derangement in energy metabolism, measured by a decrease in the ratio of ATP to its hydrolysis product inorganic phosphate. The depleted energy status was mirrored in biochemical indices of liver function, and restitution paralleled the course of restoration of hepatic cell mass., Conclusions: These findings indicate that changes in liver metabolism after surgery reflect the magnitude of tissue injury and the quantity of functioning liver cells. Acute phase responses dominate the initial recovery period at the expense of less important endergonic functions. When liver parenchyma is lost, the acute phase reaction is maintained and further supported by a rapid replenishment of hepatocytes, which can even be considered a continuation of acute phase physiology. Modulation of liver function within the framework of overall hepatic energy economy is one mechanism for matching energy supply with increased demands during these processes.

Recovery of liver cell mass following hepatectomy requires a metabolic compromise between differentiated function and organ regrowth. Clinical experience has shown that hepatic failure after resection is more common when the organ is diseased. We have evaluated intracellular hepatic biochemistry in patients with normal and cirrhotic livers undergoing partial hepatectomy, using 31-phosphorus magnetic resonance spectroscopy ((31)P MRS). Eighteen patients were studied, half with normal liver architecture (normal group, n = 9) and half with cirrhotic parenchyma (cirrhosis group, n = 9). Magnetic resonance examinations were performed preoperatively and on postoperative days 2, 4, 6, 14, and 28. Hepatic volume (estimated by magnetic resonance imaging [MRI]) and blood chemistries were measured at the same intervals. Following a comparable reduction in parenchymal volume, the cirrhotic group demonstrated a more sustained fall in adenosine triphosphate (ATP) energy state. Disturbance of membrane phospholipid metabolism and duration of acute-phase reaction were more marked when the liver was diseased. The pattern of derangement of hepatic function, however, was similar in the two groups. Overall, the recovery process was less efficient in the cirrhotic organ, and culminated in a diminished rate and extent of the regenerative response. These outcomes indicate that liver regeneration after partial hepatectomy involves modulation of hepatic energy economy in response to changing work demands. The efficiency of this process is influenced by the histopathologic state of the organ, and in turn governs the physiologic reserve. These findings may explain the mechanism of posthepatectomy liver failure, and offer a rational basis for the assessment of novel hepatic support strategies.

The planning and installation of a telemedicine system for communication within a teaching hospital and its academic and hospital units with a capacity for accommodation of up to 400 video-stations is described. The system is intended for improving the communication between patients and health professionals, and between the health professionals themselves. It also provides the basis for improving pre-graduate teaching, especially problem-based learning, and all aspects of postgraduate teaching.

Telemedicine has been shown to have a considerable impact in medical education, conferencing and consultation. As a result, the People's Republic of China has been keen to develop telemedicine. In her attempts to further the development of telemedicine, China has looked to the progress of medical services in Western countries such as Europe and North America. The United States of America, however, has exceeded the rest in exchange of health-care information and telemedicine technologies with China. Although China has been enthusiastic about the exchange, telemedicine in China requires development in the technical infrastructure and professional infrastructure.

A residential nursing home in Hong Kong was linked to the community geriatric assessment team based in a regional hospital using videoconferencing equipment operating at 384 kbit/s. The feasibility of providing nursing services and their acceptability to users were evaluated over 12 months. There were 198 occupants of the nursing home and their mean age was 82 years (range 60-101). Services included patient education regarding the use of a metered dose inhaler, wound management and a falls prevention programme, together with assessment of clients' need for infirmary care and the risk of aspiration. The acceptability of the system to the clients and nursing home staff was also assessed. It was found that 89% of such services could be carried out via telemedicine, and only 11% required on-site visits. There was an increase in the proportion of patients correctly using inhalers as well as a reduction in the number of falls. More consultations were conducted by the nurse (an increase of 76% per month) and an additional 8.4 patients per month could be attended to by the nurse compared with 5 patients when on-site visits were used. Acceptability to clients and nursing home staff was good. The problem of lack of resources to support elderly residential care institutions makes service delivery via telemedicine appear economically attractive, as well as facilitating improvements in the quality of long-term care.

Alpha-fetoprotein (AFP) is widely used as a serological marker in the diagnosis of hepatocellular carcinoma (HCC) and non-seminomatous germ cell tumours (NSGCT). By application of isoelectric focusing (IEF) disease-specific AFP isoforms can be identified. Three major bands are apparent: + 1 (associated with 'benign' liver disease), + II (associated with HCC) and +III (associated with NSGCT). Recently, we have characterized the predominant glycans of human serum AFP and now report the application of these findings and electrospray ionization-mass spectrometry (ESI-MS) to the determination of the glycan composition of the isoforms present in the sera of 12 patients with HCC and of one patient with NSGCT. ESI-MS allowed simultaneous identification of various AFP glycoforms in purified serum AFP. Seven glycoforms were identified, but with different abundance in the sera of the HCC patients, whereas six glycoforms were identified in the serum from the NSGCT patient. The glycan structures of these glycoforms were deduced from their observed masses. AFP glycoforms carrying a single biantennary complex-type N -glycan appeared as the predominant glycoforms, whereas those carrying both N -glycan and O -glycan appeared as minor glycoforms. Correlation between the abundance of the AFP glycoforms and the IEF band intensity suggested that different degrees in sialylation cause the formation of isoforms. This contention was subsequently supported by the ESI-MS and kinetic in vitro desialylation studies on purified Bands + l and + lI AFPs. Our findings indicate that HCC-associated isoforms (Band + II) represent a group of glycoproteins whose carbohydrate structures are all characterized by being mono-sialylated, whereas those associated with benign liver disease and NSGCT are di- and a-sialo species, respectively. Knowledge of the structure of the tumour-specific isoforms should form an important basis for clinically useful assays., (Copyright 2000 Cancer Research Campaign.)

Background: Recently, much interest has developed in the potential use of plasma DNA as a diagnostic and monitoring tool. We hypothesized that plasma DNA is increased in patients with trauma and may be prognostic in such patients., Methods: We studied 84 patients who had sustained an acute blunt traumatic injury. We measured plasma DNA by a real-time quantitative PCR assay for the beta-globin gene. Blood samples were collected at a median time of 60 min following injury. Blood samples were also obtained from 27 control subjects., Results: The median plasma DNA concentrations in the control, minor/moderate trauma (Injury Severity Score <16; n = 47), and major trauma (Injury Severity Score > or =16; n = 37) groups were 3154 kilogenome-equivalents/L, 13 818 kilogenome-equivalents/L, and 181 303 kilogenome-equivalents/L, respectively. Plasma DNA concentrations in patients with adverse outcomes, including acute lung injury, acute respiratory distress syndrome, and death, had 11. 6- to 12-fold higher plasma DNA concentrations than those who did not develop these complications. At a cutoff of 232 719 kilogenome-equivalents/L, the sensitivities of plasma DNA analysis for the prediction of acute lung injury, acute respiratory distress syndrome, and death were 100% (95% confidence interval, 100-100%), 100% (95% confidence interval, 100-100%), and 78% (95% confidence interval, 40-97%), respectively. The respective specificities were 81% (95% confidence interval, 71-89%), 80% (95% confidence interval, 70-88%), and 82% (95% confidence interval, 71-90%)., Conclusions: Plasma DNA is increased after trauma and may be a potentially valuable prognostic marker for these patients.

Permanent glioma cell lines are invaluable tools in understanding the biology of glioblastomas. The present study reports the establishment of a clonal human cell line, GBM6840, derived from a biopsy of paediatric cerebellar glioblastoma multiforme. GBM6840 had a doubling time of 32 h and grew as a monolayer of large round cells that retained immunopositivity for glial fibrillary acidic protein and vimentin. Karyotypic analysis revealed a modal chromosome number of 68 and polysomies of chromosomes 3, 5 and 20, as well as the presence of 3-4 marker chromosomes. GBM6840 also showed anchorage-independent growth in soft agar and tumour formation in nude mice. The p16(CDKN2A) gene was transcriptionally silenced by hypermethylation, consistent with the lack of protein expression observed in the original tumour and cultured cells. Western blot analysis revealed normal protein expression of pRb and CDK4. It appears that p16 is the major component altered in the cell cycle pathway and may confer these cells unrestrained proliferation potential. Neither EGFR gene amplification nor over-expression of the protein was detected in the cultured cells. Over-expression of the p53 protein was observed in the majority of cells, despite undetectable mutation (exons 5-8) in the gene. One allele of the PTEN gene was found to be mutated during in vitro cultivation. Telomerase activity was demonstrated in the cultured cells but not in the original tumour, supporting the hypothesis that telomerase is required for the in vitro immortalization process.

Deregulation of the G1/S checkpoint is a frequent event in the development of glioblastoma multiforme (GBM). Previous studies have shown more than 50% of primary GBM tumours contain either complete loss of the p16INK4a locus or amplification of the CDK4 gene. Moreover, many heterozygosity studies have shown deletion on human chromosome 19p13.2, where the p19INK4d gene has been localized. We examined the expression of p19INK4d and its two CDK substrates in a series of glioma-derived cell lines and tumours. No gene rearrangement or deletion was observed in the p19INK4d gene in these cell lines; however, expression of CDK4 and CDK6 was elevated relative to matched normal brain tissue in eight of 18 GBM tumours (44%). Furthermore, CDK6 expression level was increased in 12/14 glioblastomas, but undetectable in tumour samples of a previous lower grade tumour from the same patient. These data attest to the functional importance of both CDK4 and CDK6 in astrocytic tumourigenesis, particularly during the later stages of tumour progression.

Background: It has been shown that the inhibition of eosinophilic apoptosis is an important mechanism for the development of blood and tissue eosinophilia in allergic diseases. Considerable attention has recently been focused on the role played by different intracellular kinase cascades in the control of apoptosis. In the present study, we investigated the effect of sodium salicylate (NaSal), a nonsteroidal anti-inflammatory drug, on mitogen-activated protein kinases (MAPK) and apoptosis of human eosinophils., Methods: Human blood eosinophils were purified from buffy coat. NaSal-induced apoptosis of eosinophils was assessed by morphological changes and Annexin-V binding assay. Changes of MAPK activity upon treatment with NaSal were measured by kinase activity assay and Western blot., Results: NaSal could induce apoptosis of human blood eosinophils in a dose- and time-dependent manner. It could also activate c-Jun N-terminal kinase (JNK) and p38 MAPK but not extracellular signal-regulated protein kinase (ERK) activity within 1 h. Pretreatment of eosinophils with p38 MAPK and JNK anti-sense (AS) phosphorothioate oligodeoxynucleotides (ODN) or specific p38 MAPK inhibitor SB 203580 did not have any significant effect on NaSal-induced apoptosis. However, ERK AS ODNs could trigger the apoptosis of normal eosinophils., Conclusion: There is no direct relationship between the activation of JNK and p38 MAPK pathways and NaSal-induced apoptosis in human peripheral blood eosinophils., (Copyright 2000 S. Karger AG, Basel)

Although estimation of serum alpha-fetoprotein (AFP) is widely used in the diagnosis of hepatocellular carcinoma (HCC) and non-seminomatous germ cell tumours (NSGCT), the clinical usefulness of this test is limited by a low specificity. However, there exist glycoforms of AFP which may be more specific for particular tumours. Previously, detailed analysis has been prevented by the low levels of AFP in human serum. We report here the application of fluorescence labelling, sequential exoglycosidase digestion, high-performance liquid chromatography and matrix-assisted laser desorption ionization in time-of-flight mass spectrometry, to determine the glycan structures of purified serum AFP from patients with HCC and NSGCT. Eleven major glycans were found, of which seven were N-linked, and four were O-linked, to the protein backbone. The structure of the N-linked glycans (all of bi-antennary complex-type with varying degrees of sialylation, fucosylation and galactosylation) were consistent with those previously reported. The O-linked glycans (three mucin O-GalNAc type glycans with variable degrees of sialylation, one O-HexNAc monosaccharide glycan) have not previously been reported. The finding of mucin O-GalNAc type glycans was supported by the prediction of potential O-GalNAc glycosylation sites on the protein backbone by analysis of the AFP structure by molecular modelling. With knowledge of these structures it may be possible to develop more specific assays for the detection of HCC and NSGCT.

Recently, cell-free EBV DNA has been detected in the plasma and serum of patients with nasopharyngeal carcinoma (NPC). We studied the relationship between plasma/serum EBV DNA and tumor recurrence. Using real-time quantitative PCR, the median plasma EBV DNA concentration in 10 patients with tumor recurrence was determined to be 32,350 copies/ml, whereas that in 15 patients in continuous remission for a mean period of 2 years was 0 copy/ml. Longitudinal follow-up of 17 NPC patients revealed 6 individuals with tumor recurrence and 11 patients who remained in remission. Significant elevations in serum EBV DNA, sometimes up to 6 months before detectable clinical deterioration, were observed in the patients who subsequently developed tumor recurrence. Continuously low or undetectable levels of serum EBV DNA were observed in the patients who remained in remission. These results suggest that plasma/serum cell-free EBV DNA may be a valuable tool for the monitoring of NPC patients for the early detection of tumor recurrence.

Background: The recent discovery of the presence of circulating cell-free fetal DNA in maternal plasma opens up new prenatal diagnostic applications and provides new avenues for clinical investigation. It is of research and potential diagnostic interest to determine whether fetal trisomy 21 may be associated with quantitative abnormalities of circulating fetal DNA in maternal plasma., Methods: Maternal plasma samples were prospectively collected from two centers situated in Hong Kong and Boston. Samples collected from Boston consisted of 7 women carrying male trisomy 21 fetuses, 19 carrying euploid male fetuses, and 13 carrying female fetuses. Samples collected from Hong Kong consisted of 6 women carrying male trisomy 21 fetuses, 18 carrying euploid male fetuses, and 10 carrying female fetuses. Male fetal DNA in maternal plasma was measured using real-time quantitative Y-chromosomal PCR., Results: For patients recruited from Boston, the median circulating fetal DNA concentrations in women carrying trisomy 21 and euploid male fetuses were 46.0 genome-equivalents/mL and 23.3 genome-equivalents/mL, respectively (P = 0.028). For patients recruited from Hong Kong, the median circulating fetal DNA concentrations in women carrying trisomy 21 and euploid male fetuses were 48.2 genome-equivalents/mL and 16.3 genome-equivalents/mL, respectively (P = 0.026). None of the samples from women carrying female fetuses had detectable Y-chromosomal signals., Conclusions: Abnormally high concentrations of circulating fetal DNA are found in a proportion of women carrying fetuses with trisomy 21. The robustness and reproducibility of real-time PCR analysis of maternal plasma makes it a valuable tool for cross-institutional collaboration involving centers located in different parts of the world.

Haematopoietic cytokines such as IL-3, IL-5 and GM-CSF not only activate eosinophils but also prolong their life span by inhibiting their apoptotic cell death. We have studied the effects of IL-3, IL-5 and GM-CSF on apoptosis and mitogen-activated protein kinases (MAPKs) in a human eosinophilic leukaemic cell line (EoL-1). Results demonstrated that all three cytokines could trigger the receptor-mediated activation of extracellular signal-regulated kinase (ERK) within one hour but not p38 MAPK activity in EoL-1 cells. In contrast, sodium salicylate (NaSal), a nonsteroidal anti-inflammatory drug (NSAID), could activate p38 MAPK but not ERK within one hour. Both cytokines and specific p38 MAPK inhibitor SB 203580 could partly block the NaSal-induced apoptosis in EoL-1 cells. A specific MAPK/ERK kinase (MEK) inhibitor, PD 098059, could induce apoptosis and eliminate the protective effect of IL-3, IL-5 and GM-CSF against NaSal-induced apoptosis in EoL-1 cells. Taken together, cytokines IL-3, IL-5 and GM-CSF could prolong EoL-1 cells survival through the transient activation of ERK. On the other hand, activation of p38 MAPK in EoL-1 cells by NaSal could lead to apoptosis. Activation of p38 MAPK and the resulting induction of apoptosis in EoL-1 cells may be important to explain the anti-inflammatory action of NSAID in allergic inflammation.

We have developed a quantitative method for methylation analysis of the p16 gene based on real-time methylation-specific PCR (MSP). Real-time MSP is sensitive enough to detect down to 10 genome equivalents of the methylated p16 sequence. Application of real-time MSP to DNA from tumor-derived cell lines revealed complete concordance with conventional MSP analysis. Quantitative data generated by real-time MSP were expressed as the methylation index, which was defined as the percentage of bisulfite-converted DNA that consisted of methylated target sequences. The methylation index was shown to be inversely correlated with p16 gene transcription during demethylation treatment of cell lines with 5-aza-2'-deoxycytidine. The application of real-time MSP to bone marrow aspirates from patients with multiple myeloma revealed complete concordance with conventional MSP analysis. Real-time quantitative MSP may have applications in elucidating diverse biological processes involving DNA methylation and may become a valuable diagnostic tool for detecting tumor-associated epigenetic changes in cancer patients.

Purification of enough eosinophils for the study of allergic inflammation is difficult because eosinophils comprise only a small percentage of circulating leucocytes. A human eosinophilic leukemic cell line, EoL-1, has been considered to be an in vitro eosinophilic model. In the present study, the suitability of EoL-1 cells as an eosinophilic model was further investigated. EoL-1 cells were induced to differentiate by dibutyryl cyclic AMP (dbcAMP). The expression of cell surface cytokines (IL-3, IL-5, GM-CSF) receptors, adhesion molecules (CD49d, CD11b), and CD95 (Fas) was investigated by flow cytometry. Expression of eosinophilic cationic protein (ECP) was determined by fluorescence enzyme immunoassay (FEIA) and reverse transcription-polymerase chain reaction (RT-PCR). EoL-1 cells could be differentiated into eosinophilic vacuole-containing cells by dbcAMP. They were found to express cell surface IL-3 and GM-CSF receptors, CD95 and CD49d. Treatment with dbcAMP could induce the expression of CD11b but decrease the expression of CD95. Anti-CD95 antibody could induce their apoptosis. The differentiation of EoL-1 cells was accompanied by increase in release of ECP into the supernatant and total ECP synthesis. Differentiation of EoL-1 cells also up-regulated the expression of mRNA for ECP and its level was parallel to the total amount of ECP synthesis. By virtue of their expression of haematopoietic cytokines receptors, adhesion molecules, CD95, synthesis and release of ECP, EoL-1 cells are suitable as an in vitro eosinophilic model for studying eosinophilic functions.

Systemic primary carnitine deficiency (CDSP, OMIM 212140) is an autosomal recessive disease characterized by low serum and intracellular concentrations of carnitine. CDSP may present with acute metabolic derangement simulating Reye's syndrome within the first 2 years of life. After 3 years of age, patients with CDSP may present with cardiomyopathy and muscle weakness. A linkage with D5S436 in 5q was reported in a family. A recently cloned homologue of the organic cation transporter, OCTN2, which has sodium-dependent carnitine uptake properties, was also mapped to the same locus. We screened for mutation in OCTN2 in a confirmed CDSP family. One truncating mutation (Trp132Stop) and one missense mutation (Pro478Leu) of OCTN2 were identified together with two silent polymorphisms. Expression of the mutant cDNAs revealed virtually no uptake activity for both mutations. Our data indicate that mutations in OCTN2 are responsible for CDSP. Identification of the underlying gene in this disease will allow rapid detection of carriers and postnatal diagnosis of affected patients.

Using real-time quantitative PCR, cell-free EBV DNA was detectable in the plasma of 96% (55 of 57) of nasopharyngeal carcinoma (NPC) patients (median concentration, 21058 copies/ml) and 7% (3 of 43) of controls (median concentration, 0 copies/ml). Advanced-stage NPC patients had higher plasma EBV DNA levels than those with early-stage disease. At 1 month after completion of radiotherapy, plasma EBV DNA was undetectable in 7 of 15 subjects (47%) but remained high in the remaining 8 subjects (53%). Clinical examination revealed that all of the former seven subjects had complete tumor regression, whereas six of the eight latter subjects exhibited evidence of disease persistence or had developed distant metastases. These results suggest that quantitative analysis of plasma EBV DNA may be a useful clinical and research tool in the screening and monitoring of NPC patients.

We have studied the feasibility of detecting tumor-associated aberrant p16 methylation in the circulation of patients with hepatocellular carcinoma (HCC). We extracted DNA from the tumor tissues and peripheral blood plasma or serum of 22 HCC patients. p16 methylation was found in 73% (16 of 22) of HCC tissues using methylation-specific PCR. Among the 16 cases with aberrant methylation in the tumor tissues, similar changes were also detected in the plasma/serum samples of 81% (13 of 16) of the cases. No methylated p16 sequences were detected in the peripheral plasma/serum of the six HCC cases without these changes in the tumor, in 38 patients with chronic hepatitis/cirrhosis, or in 10 healthy control subjects. These results suggest that circulating liver tumor DNA may be detected using tumor-associated DNA methylation changes. Because methylation abnormalities have been found in many other genes and tumor types, this approach may have implications for the noninvasive detection of a wide variety of cancers.

Fetal DNA has been detected in maternal plasma during pregnancy. We investigated the clearance of circulating fetal DNA after delivery, using quantitative PCR analysis of the sex-determining region Y gene as a marker for male fetuses. We analyzed plasma samples from 12 women 1-42 d after delivery of male babies and found that circulating fetal DNA was undetectable by day 1 after delivery. To obtain a higher time-resolution picture of fetal DNA clearance, we performed serial sampling of eight women, which indicated that most women (seven) had undetectable levels of circulating fetal DNA by 2 h postpartum. The mean half-life for circulating fetal DNA was 16.3 min (range 4-30 min). Plasma nucleases were found to account for only part of the clearance of plasma fetal DNA. The rapid turnover of circulating DNA suggests that plasma DNA analysis may be less susceptible to false-positive results, which result from carryover from previous pregnancies, than is the detection of fetal cells in maternal blood; also, rapid turnover may be useful for the monitoring of feto-maternal events with rapid dynamics. These results also may have implications for the study of other types of nonhost DNA in plasma, such as circulating tumor-derived and graft-derived DNA in oncology and transplant patients, respectively.

Objectives: The aims of this study were to estimate the dietary intake of phytoestrogens and to measure urinary phytoestrogen excretion in postmenopausal Chinese women., Methods: Postmenopausal Chinese women were recruited from the hormone replacement clinic of the Prince of Wales Hospital. Dietary intake of phytoestrogen-rich foods was estimated using a food frequency questionnaire. Urinary output of the isoflavonoids daidzein and genistein and the metabolite of daidzein, equol, was measured using high-performance liquid chromatography., Results: The mean daily excretion of daidzein, genistein and equol was 3.24 (+/- 3.63), 1.47 (+/- 1.75) and 0.64 (+/- 1.53) mumol, respectively. The total mean daily isoflavonoid excretion was 5.36 (+/- 5.27) mumol., Conclusions: Urinary excretion of isoflavonoid phytoestrogens in this Chinese population was lower than that reported in Japanese subjects. This may be due to the higher consumption of legumes, especially soy products, in the Japanese compared to the Chinese diet. The intake of green vegetables was higher in the Chinese subjects, and this food group may be the main contributor to their total phytoestrogen intake.

When treatment with diazoxide and somatostatin for persistent hyperinsulinaemic hypoglycaemia of infancy failed, subtotal pancreatectomy was performed on a neonate on day 41. The pancreatic tissue was saved and used for immunohistochemical and cell culture studies. The initial immunohistochemistry of beta cells for insulin was negative, using a 1 in 200 dilution of insulin antiserum, but positive results were obtained with an increased concentration of the antiserum. The insulin to somatostatin cell ratio in islets of Langerhans was about 1:1, with no somatostatin cells outside the islets. Glucose stimulated insulin secretion in a concentration dependent manner in vitro. Isobutyl methyl xanthine doubled insulin secretion, but lithium had no effect. The glucose stimulated insulin secretion was inhibited by somatostatin, epinephrine, and in the absence of Ca2+. In view of the normal in vitro responses of beta cells to various secretory analogues, the lack of responsiveness to somatostatin analogue before pancreatectomy may not have been due to deficiency or resistance to somatostatin, but to beta cell hyperplasia overwhelming the paracrine regulatory mechanism(s).

Doctors have recently gained substantial experience of using telemedical applications for consultations, education and training, and conferences. What is still lacking is systematic evaluation of these new approaches compared with traditional procedures. Trials involving consultations for diagnostic, monitoring, and interpretative purposes should be blinded and multicentred, and should include tests of patient satisfaction as well as macro-economic considerations. The quality of educational programmes and conferences should be documented and compared with traditional teaching methods. International standards need to be developed for such evaluations, to allow comparisons between trials performed at national and international levels. Hong Kong is in a good position to contribute to these developments because of a well-integrated health care system and excellent telecommunication facilities. Through telemedicine, Hong Kong could resume a leading global position in the use of advanced information technology.

We have developed a real-time quantitative PCR assay to measure the concentration of fetal DNA in maternal plasma and serum. Our results show that fetal DNA is present in high concentrations in maternal plasma, reaching a mean of 25.4 genome equivalents/ml (range 3.3-69. 4) in early pregnancy and 292.2 genome equivalents/ml (range 76. 9-769) in late pregnancy. These concentrations correspond to 3.4% (range 0.39%-11.9%) and 6.2% (range 2.33%-11.4%) of the total plasma DNA in early and late pregnancy, respectively. Sequential follow-up study of women who conceived by in vitro fertilization shows that fetal DNA can be detected in maternal serum as early as the 7th wk of gestation and that it then increases in concentration as pregnancy progresses. These data suggest that fetal DNA can be readily detected in maternal plasma and serum and may be a valuable source of material for noninvasive prenatal diagnosis.

Glycogen storage disease type la (GSD1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase genes of two unrelated Chinese families with GSD1a. DNA sequencing of all five exons and the exon-intron boundaries revealed a G T transversion at nucleotide 727 (727G-->T) in exon 5, which has previously been reported to cause abnormal splicing. In one family, the subject and her affected sister were confirmed to be homozygous for this mutation and their parents to be heterozygotes. In the other family, the proband was identified to be heterozygous for this mutation, and a novel mutation, the 341delG in exon 2, was identified. This mutation alters the reading frame and creates a stop codon TAA 15 codons downstream from the mutation, resulting in a truncated protein. Family studies revealed that the father was heterozygous for the 727G-->T mutation and that the mother was heterozygous for the 341delG mutation. This is the first time that the 727G T mutation has been found in Chinese patients or outside Japan. Since we only tested two GSD1a families and found 727G-->T in both, we believe that this mutation may also be prevalent in our local Chinese population. To investigate allele frequencies, we screened 385 Chinese healthy volunteers and found two asymptomatic carriers. Our findings suggest that the 727G-->T mutation is indeed prevalent in Hong Kong.

Chinese Telemed 96, a three way international telemedicine conference was successfully held in November 1996. Over 1,000 physicians, allied health professional and medical students participated in this conference in Beijing, Hong Kong and London. This program demonstrated that the quality of telecommunication technology was suitable for the Chinese University of Hong Kong, Faculty of Medicine to use it in facilitating medical consultations and sharing expertise among widely dispersed colleagues. The consensus of Hong Kong participants was that the audiovideo and telecommunication technology used in this conference were adequate. In order to improve overall quality, however, a better co-ordination of the technical support across sites is required. Other felt that the conference suffers from the shortage of highly trained technical staff required to support the communication system. However, following the total evaluation of this conference, it is concluded that while technical support, site and location are important factors in a good telemedicine conference, a well run telemedicine conference is more dependent on a sound planning process and its execution.