From Wearable Sensors to Smart Implants--Toward Pervasive and Personalized Healthcare.

OBJECTIVE: This paper discusses the evolution of pervasive healthcare from its inception for activity recognition using wearable sensors to the future of sensing implant deployment and data processing. METHODS: We provide an overview of some of the past milestones and recent developments, categorized into different generations of pervasive sensing applications for health monitoring. This is followed by a review on recent technological advances that have allowed unobtrusive continuous sensing combined with diverse technologies to reshape the clinical workflow for both acute and chronic disease management. We discuss the opportunities of pervasive health monitoring through data linkages with other health informatics systems including the mining of health records, clinical trial databases, multiomics data integration, and social media. CONCLUSION: Technical advances have supported the evolution of the pervasive health paradigm toward preventative, predictive, personalized, and participatory medicine. SIGNIFICANCE: The sensing technologies discussed in this paper and their future evolution will play a key role in realizing the goal of sustainable healthcare systems.

Chlorinated pesticides in foodstuffs in Hong Kong.

The movement of pesticides into and out of Hong Kong shows a high net gain of DDT and benzene hexachloride (BHC). 310 food samples were analyzed for total BHC and 1,854 food samples were analyzed for total DDT, total DDE, and total TDE. High levels of total BHC and total DDT were found in foodstuffs in Hong Kong. Estimated daily ingestion of total BHC and total DDT were 10 and 9 times higher than that found in the United States of America. These results correlate with the known high body accumulations of beta BHC and p,p' DDT as shown in high pesticides levels of local human breast milk. Certain foodstuffs, such as preserved fruits, preserved eggs, salted fish and pond fish, had very high levels of pesticides. Sources of contamination and existing government legislations are discussed and recommendations made.

Hepatitis B infection in infants after neonatal immunization.

A double-blind randomized placebo-controlled study to prevent hepatitis B infection in 235 babies born to chronic hepatitis B, HBeAg carriers was carried out. Babies in three treatment groups all received heat-inactivated hepatitis B vaccine. In addition multiple doses of HBIG and a single dose of HBIG were given in groups I and II respectively. After three years of follow-up, 4/60 (Group I), 3/64 (Group II), and 1/64 (Group III) developed chronic infection. For those who escaped chronic infection, other hepatitis events also occurred. They were transient HBs-antigenaemia, anti-HBc conversion and significant rise in anti-HBs titre without seroconversion for anti-HBc. It was deduced that 30% of babies born to hepatitis carriers are naturally protected from chronic infection. Immunization, with vaccine only, protects another 46%. The addition of single and multiple doses of HBIG protects another 10% and 5%, respectively. 2% acquired intrauterine infection and 7% failed to respond to the most intensive immunization schedule.

Organochlorine chemicals in human breast milk in Hong Kong.

The results of a small-scale survey of organochlorine contaminants in human breast milk are presented and compared to previous data from 1976 for Hong Kong, and to reported data from elsewhere. Concentrations of p,p DDT, dieldrin and hexachlorobenzene (HCB) in recent breast milk samples were slightly but significantly lower than those in samples taken a decade previously in Hong Kong. However, levels of gamma-HCH (hexachlorocyclohexane) were higher in the more recent samples. The concentrations of DDT, DDE and beta-HCH in Hong Kong breast milk remain among the highest reported in the literature. Probable routes of uptake of such contaminants include the ingestion of seafood, as these same compounds have previously been found at high concentrations in mussels from Hong Kong waters. Data for organochlorine levels in breast milk from other parts of Asia are not available, but trends in global pesticide usage suggest that significant contamination elsewhere in the continent is likely.

Prevention of hepatitis B virus carrier state in infants according to maternal serum levels of HBV DNA.

235 infants of HBeAg-carrier mothers in Hong Kong were assigned to four study groups. Groups I, II, and III received hepatitis-B (HB) vaccine at birth and at 1, 2, and 6 months. Group I also received seven monthly injections of HB immunoglobulin (HBIg), and group II received one HBIg injection at birth. Group III received vaccine only and group IV received placebo for both vaccine and HBIg. At the age of 3 years, all infants of the three treatment groups were significantly protected against the HB virus (HBV) carrier state compared with the placebo group (p less than 0.0001); the protective efficacy rates in groups I, II, and III were 87%, 80%, and 65%, respectively. At all times, group I was significantly better protected than group III. In groups III and IV, infants of mothers with serum HBV DNA levels of 5 pg/ml or above were at a significantly higher risk of acquiring the HBV carrier state than those whose mothers had HBV DNA levels below 5 pg/ml. This difference was not significant in groups given HBIg. Of the 183 infants who initially escaped HBV infection, 73 (40%) had transient and 8 (4%) chronic HBV infection between 6 and 36 months. Vaccinated infants who had actively formed anti-HBs remained well protected against the HBV carrier state. However, infants in groups I and II with no active anti-HBs response to vaccine became at risk for the HBV carrier state when the passively acquired anti-HBs antibodies had disappeared. HBIg should be included in HB vaccination schedules for all infants of HBeAg-positive mothers.

Prevention of the HBsAg carrier state in newborn infants of mothers who are chronic carriers of HBsAg and HBeAg by administration of hepatitis-B vaccine and hepatitis-B immunoglobulin. Double-blind randomised placebo-controlled study.

Newborn infants of Chinese HBeAg-carrier mothers in Hong Kong were randomly assigned to one of four study groups. Group I was treated with 3 micrograms heat-inactivated hepatitis B (HB) vaccine at birth and at 1, 2, and 6 months thereafter, in conjunction with seven monthly HBIg injections; group II was treated according to the same vaccine schedule but received only one HBIg injection at birth; group III received only the vaccine, at months 0, 1, 2, and 6; and group IV received placebos for both vaccine and HBIg. The first set of injections was given within 1 h after birth. Comparisons were made in the 140 children who were at least six months old at the close of the trial (495 days). In all three treatment groups development of the persistent carrier state was significantly (p less than or equal to 0.0001) less frequent than in controls (2.9%, 6.8%, and 21.0% versus 73.2%). Although vaccination alone was significantly less protective than vaccination plus multiple HBIg injections (p = 0.03), the degree of protection was still remarkable. 12 months after the first set of injections 96-100% of the infants in the three treatment groups were anti-HBs positive; the geometric mean titres of anti-HBs in the three groups did not differ significantly. This indicates that even high doses of HBIg do not interfere with the anti-HBs response to the vaccine. Probable intra-uterine HB infections were observed in 3 infants. No serious side-effects were observed from the interventions, even in the babies with intra-uterine infections who had received HBIg and HB-vaccine at birth. To prevent development of the persistent HBsAg carrier state, and thereby the consequent chronic liver disease and/or primary carcinoma of the liver, HB vaccine and HBIg should be administered as soon as possible after birth to all newborn infants at risk of perinatal hepatitis B infection.

Transmission of hepatitis B antigens from symptom free carrier mothers to the fetus and the infant.

Materno-fetal transmission of hepatitis B was studied in 97 healthy carriers of hepatitis B surface antigen (HBsAg). Antepartum transmission occurred in at least 10 per cent. Intrapartum transmission may have occurred in about 40 per cent as a result of swallowing of the infective fluid by the baby during delivery, and materno-fetal transfusion during labour. Person to person transmission after delivery played a minor role. The presence of hepatitis B associated e antigen (HBeAg) in 48 per cent of maternal serum correlated strongly with the subsequent presence of antigen in the infants. There was a linear association between the incidence of antigens in cord blood and the duration of the first stage of labour, with a significant association when labour exceeded nine hours. Caesarean section is recommended if mothers have HbeAg; likewise amniocentesis and breast feeding should be discouraged if mothers have HbeAg.

Mechanisms of maternal-fetal transmission of hepatitis B virus.

In a prospective study of maternal-fetal transmission of hepatitis B virus in 125 healthy mothers who were carriers of hepatitis B surface antigen (HBsAg), preliminary results showed that the most important determinant in such transmission was the presence of hepatitis B e antigen in the mother. HBsAg was detectable by solid-phase radioimmunoassay in 33% of amniotic fluid samples, 50% of cord blood samples, 71% of breast milk samples, and 95.3% of samples of gastric contents from newborns. The presence of HBsAg in gastric aspirate from the infants immediately after birth in almost all cases suggests a universal mechanism of infection by the oral route during delivery. In light of these findings, precautions such as possible elective cesarean section, routine gastric aspiration of the newborn, avoidance of breast-feeding, etc., should be taken to avoid perinatal transmission.

Intrauterine growth in Hong Kong Chinese.

The recorded data on birth weight and gestational age of 16,836 babies born at Tsan Yuk Hospital in Hong Kong for the years 1970 to 1972 was analysed by computer. The means, standard deviations, and percentiles were separately obtained for nine sub-groups between 28 and 42 weeks and they were compared with similar series from Taiwan, Singapore, America and England. Chinese babies in Hong Kong were significantly heavier compared to most series between 32 and 35 weeks (p less than or equal to 0.001), and consistently lighter compared to all series studied between 38 and 42 weeks (p less than or equal to 0.001). Reasons for these findings are discussed.

Hospital Salmonella johannesburg infection and its possible role in the community spread of the infection in Hong Kong.

Salmonella johannesburg (1, 40: b: e, n, x), a previously rare salmonella serotype, has established itself rapidly as an important and highly prevalent cause of gastroenteritis among children. The clinical features of the infection are usually mild but chronic. It has been suggested that S. johannesburg was introduced into Hong Kong through imported foods but no common vehicle could be traced as the source of infection. A thorough investigation of one paediatric ward in a general hospital revealed that non-infected patients admitted to the ward usually acquired S. johannesburg infection within 3-7 days, with or without symptoms. Thus hospital cross-infection could be a significant factor in contributing to its rapid spread in the community. Furthermore, the rapidity with which S. johannesburg spread was facilitated by (a) its tendency to produce a chronic infection, (b) its multiple resistance to antibiotics, and (c) the higher infectivity of S. johannesburg over other salmonellas endemic in this locality. These factors combined with the overcrowded conditions in many of the hospitals in Hong Kong facilitated the occurrence of hospital infection, which in its turn contributed to the spread of the infection in the local community.

Neonatal infection due to Salmonella worthington transmitted by a delivery-room suction apparatus.

An outbreak of diarrhoea due to Salmonella worthington in five newborn babies, 5 weeks after a similar outbreak in 13 babies for which no cause had been found, occurred in the nursery of a maternity ward. The source of infection was traced to the contaminated rubber tubing of a mechanical suction apparatus. S. worthington was isolated from the rubber tubing and the Y connexion of the suction apparatus from which all the five infected babies had received suction. Reflux of contaminated amniotic fluid into the sterile catheter connected to the apparatus some time before use could have been the means of introducing the infected material to the oropharynx of the newborn babies, and amniotic fluid, acting as a good medium to support the growth of S. worthington, might be responsible for the long-lasting contamination.