Biomedical subjects

P C Fan

Publications and source records attributed to P C Fan.

At least 37 records · Page 2Linked to original sources

PubMed1998

Survival of Taenia solium cysticerci in carcasses of pigs kept at 4 C.

In the present study, the survival of cysticerci of Taenia solium in carcasses of 1 Small-Ear-Miniature and 2 Landrace Small-Ear-Miniature pigs kept in a refrigerator at 4 C was determined. The viability of the cysticerci was determined by observing evagination and active movement of the scolex under a fluorescent light after digestion in pig bile. Although no viable cysticerci were found after day 30, 58.8% cysticerci survived between day 26 and day 30. Moreover, more than 80% of the cysticerci were viable between day 1 and day 25. These findings indicate that taeniasis solium can be transmitted through eating raw or undercooked pork or viscera of pigs following refrigeration at 4 C for less than 30 days.

Animals↗

PubMed1998

Egg production capacity of Paragonimus pulmonalis in cats.

In the present study, each of 43 cats was fed with a single metacercaria of Paragonimus pulmonalis and 2 cats (controls) with 2 metacercariae. They were killed 22-372 days postinfection. In the test group, 18 (41.9%) cats were infected, as well as the 2 cats in the control group. Among the 18 worms recovered from the test group, 9 found in the lungs were mature, whereas 5 mature and 4 immature worms were in the pleural cavity. Most eggs from worms encased in a cyst were passed in the feces. However, eggs from worms in the pleural cavity were only found on the lung surface and pleural cavity. Mature worms in cysts seemed to exhibit higher egg production capacity than those in the pleural cavity. Paired mature worms from a cyst laid more eggs than a single encysted mature worm in vitro at room temperature.

Animals↗

PubMed1997

Urine lipids in patients with a history of filariasis.

The presence of lipids in postprandial urine was assessed in 116 patients with a history of filariasis and 70 normal individuals using a biochemical autoanalyzer. Urinary triglycerides (TGs) ranging from 10 to 1955 mg/dl were detected in 13 individuals with a history of chyluria, including 3 with TG levels ranging from 233 to 1955 mg/dl and cholesterol levels of 6-35 mg/dl. Three patients who had a filarial history but without chyluria were also found to have urinary TGs (13-15 mg/dl) without detectable cholesterol. Neither TGs nor cholesterol were detected in the urine of normal individuals. Fluctuations in postprandial urine lipid contents were measured by time course determinations of urinary TG and cholesterol in 17 patients with filariasis and a history of chyluria, 16 patients with filariasis and hydrocele and 16 normal individuals. The level of urine lipid excretion was found to increase within 1-4 h postprandially, with urinary TG levels ranging between 7.8 and 1284 mg/h in eight patients and urinary cholesterol levels between 1.2 and 138 mg/h in seven patients with a history of chyluria. To evaluate the origin of the urine lipids in hematochyluria, fish oil containing 360 mg eicosapentaenoic acid (EPA) and 240 mg docosahexaenoic acid (DHA) was prescribed to a patient with hematochyluria. The excretion of EPA and DHA in urine was increased postprandially in the patient, similar to the elevation of urinary TG and cholesterol. The profile of fatty acids from urine samples showed it was of dietary origin. Our results suggest that postprandial urine lipids, especially TG, might be used as markers for the clinical evaluation of chyluria.

Adult↗

PubMed1997

In vitro hatched oncospheres of Asian Taenia from Korea and Taiwan develop into cysticerci in the peritoneal cavity of female scid (severe combined immunodeficiency) mice.

In vitro hatched (but not activated) oncospheres of Asian Taenia obtained in Korea and Taiwan, prepared by the sodium hypochlorite method, rinsed with sterile PBS several times and adjusted to 5 x 10(4)/0.5 ml PBS, were injected intraperitoneally or subcutaneously into male or female scid mice of 3 different strains. When these scid mice were sacrificed 4 months later, the females harboured fully developed cysticerci either in the peritoneal cavity or under the back skin, whereas males did not. All cysticerci from the peritoneal cavity were easily recovered by rinsing the abdomen with PBS. Although most cysticerci recovered from pig liver usually become calcified within 1-2 months, in female scid mice they all increased in size and were viable. Intraperitoneal (i.p.) injection of in vitro hatched oncospheres is recommended for easier recovery of Asian Taenia metacestodes in laboratory animals.

Animals↗

PubMed1997

A comparative study on egg hatching methods and oncosphere viability determination for Taenia solium eggs.

The efficiencies of an enzyme method and the sodium hypochlorite method in hatching eggs of Taenia solium (Henan strain) were compared. The viability of the hatched oncospheres was determined by staining with trypan blue. For the former method, the hatching rate and viability percentage were 85.7% and 79.7%, respectively. The corresponding figures for the latter method were 97.9% and 86.7%, respectively. These findings indicate that the sodium hypochlorite method is a simple, efficient and practical method for hatching eggs of Taenia solium.

Animals↗

PubMed1997

Annual economic loss caused by Taenia saginata asiatica taeniasis in East Asia.

Taeniasis is an important medical and economic problem in many countries in East Asia, especially in the mountainous and remote areas where the inhabitants are fond of eating raw or undercooked meat. P.C. Fan here discusses how sociocultural factors and local customs can contribute to the transmission of taeniasis and evaluates the economic losses caused by the disease.

Journal Article↗

PubMed1997

Human Taenia eggs develop into cysticerci in scid mice.

The intermediate hosts for Taenia saginata and T. solium are cattle and pigs (and humans for the latter), respectively. In vitro-hatched (but not activated) oncospheres of both Asian Taenia (T. saginata asiatica, a new subspecies of T. saginata or T. asiatica, a new species) and T. solium injected subcutaneously into the backs of mice with severe combined immunodeficiency (scid) developed into fully matured cysticerci. Five-month-old metacestodes of Asian Taenia had no hooklets and were bigger in size than those previously reported and similar to those of T. saginata. Their morphology suggested that the cysticerci were more advanced than those in the intermediate host animals. It is suggested that scid mice are valuable experimental animal models for studying human taeniid cestode infections.

Animals↗

PubMed1997

Vaccination trials against Taiwan Taenia eggs in pigs injected with frozen oncospheres of Taiwan Taenia, Korea Taenia, T. saginata or T. solium.

When Small-Ear-Miniature pigs subcutaneously injected once with frozen oncospheres of Taiwan Taenia, Korea Taenia, T. saginata or T. solium emulsified with Freund's complete adjuvant (1.6 x 10(4)/0.4 ml) were challenged orally with 1.6 x 10(4) viable eggs of Taiwan Taenia 41 days later, they all showed strong resistance compared with pigs vaccinated with T. solium. Most pigs (5/8) of the former 3 groups harboured no cysticerci. The number of cysticerci was 5.5 +/- 9.1 (mean +/- S.D.), whereas pigs of the T. solium group and control group harboured 160 +/- 30.1 and 661 +/- 637.2 cysticerci, respectively. All cysticerci recovered from vaccinated pigs and most cysticerci in control pigs were degenerated or calcified at 36-55 days after oral egg challenge. These results strongly suggest that oncospheres of Taiwan Taenia and Korea Taenia are very similar to T. saginata in their immunogenicity in pigs.

Animals↗

PubMed1997

Sociocultural factors and local customs related to taeniasis in east Asia.

Taeniasis is an important medical and economic problem in many countries in East Asia. According to our estimation, there is an annual loss of US$18,673,495, US$13,641,021, and US$2,425,500 due to taeniasis in the mountainous areas of Taiwan, Cheju Island of Korea, and Samosir Island of Indonesia, respectively. Although taeniasis and cysticercosis due to Taenia solium have been reported, T. saginata asiatica is the dominate species in part of the world, especially in the mountainous and remote areas where the inhabitants are fond of eating raw or undercooked meat and/or viscera of domestic or wild animals. Therefore, sociocultural factors and local customs are the determinants in the transmission of taeniasis. In this paper, local customs and sociocultural factors including local dishes, accidental infection during dish preparation, and treatment for anaemia of children in the countries of East Asia were reviewed.

Adolescent↗

PubMed1997

Annual economic loss caused by Taenia saginata asiatica taeniasis in three endemic areas of east Asia.

The Taenia saginata-like tapeworm in East Asia has been designed as a separate subspecies of T. saginata. It was named as T. saginata asiatica and the classical T. saginata as T. saginata saginata. In the course of conducting experimental infections and morphological studies, a large number of adult worms of T. saginata asiatica was collected. It is possible to estimate the annual economic loss caused by this infection, since the worm load and the weight of worm habored by each infected person were determined from the collection. In the mountainous areas of Taiwan, the infection rate of T. saginata asiatica taeniasis was 11.0%, the worm load was 1.6 worms/case, and the average weight of an adult worm was 20.5 g. The annual economic loss was estimated to be US$ 11,327,423. On Cheju Island of Korea, the infection rate was 6.0%, the worm load was 2 worms/case, and the average weight of an adult worm was 19.3 g. The annual economic loss was estimated to be US$ 13,641,021. On Samosir Island of Indonesia, the infection rate was 21%, the worm load was 1.8 worms/case, and the average weight of an adult worm was 22 g. The annual economic loss was estimated to be US$ 2,425,500. These figures indicate that taeniasis is not only a significant public health problem but also an important economic problem in East Asia.

Animals↗

PubMed1996

Experimental studies on the pathway for migration and the development of Taiwan Taenia in domestic pigs.

The pig is the most favorable experimental intermediate host of Taiwan Taenia. Cysticerci in infected pigs are located in the liver except for a few extrahepatic ones. The present study was designed to investigate the pathway of migration of the oncospheres of Taiwan Taenia in the pig. In the first group, each of 5 Small-Ear-Miniature (SEM) and one Landrace-Small-Ear-Miniature (L-SEM) pigs were injected with 5000 hatched oncospheres into the ear vein. Three SEM and one L-SEM pigs were found to harbor 88 degenerated or calcified cysticerci only in the liver 51-81 days after injection. In the second group, each of 3 L-SEM pigs were injected with 5000 hatched oncospheres into the jugular vein. One of the 3 pigs was found to have 5 cysticerci (2 mature and 3 degenerated or calcified) only in the liver at 89 days post-injection. In the third group, each of 4 SEM, three L-SEM, and 3 L-SEM pigs were injected with 10,000, 10,000, and 5000 hatched oncospheres, respectively, directly into the portal vein after surgical opening of the abdominal cavity. All 10 pigs were found to be infected with a total of 1088 cysticerci (44 mature and 1044 degenerated or calcified) only in the liver 23-62 days after injection. Although the sites of injection in these three groups were different, the liver was the only final location of the cysticerci. These findings give strong evidence that the oncospheres migrate to the liver through the venous circulation and develop in this organ.

Animals↗

PubMed1996

Ectopic locations of Taenia saginata asiatica cysticerci in the abdominal cavity of domestic pig and monkey.

Eleven Small-Ear-Miniature pigs, 1 Landrace Small-Ear-Miniature pig, and 1 monkey (Macaca cyclopis) were infected experimentally with eggs of Taenia saginata asiatica. They were found to harbor cysticerci on the liver surface, each with a thin, whitish fiber connecting to another location in the same lobe, or to other lobes of the liver; some were also connected individually to the diaphragm, abdominal muscles, and gall bladder with a short, thin fiber. Moreover, they also harbored extrahepatic cysticerci. Most of these were observed on the omentum and in the peritoneal cavity, except for some suspended individually in the abdominal cavity by a long, thin, whitish fiber. The origin of the extrahepatic cysticerci and whitish fibers is probably from the surface of the liver of the host.

Abdomen↗

PubMed1996

Rigid bronchoscopy and jet ventilation in an extremely low birthweight infant.

Until recently, rigid bronchoscopy was considered too risky for premature infants. We report a 658 g infant with life-threatening mediastinal shift due to right pulmonary atelectasis. Rigid bronchoscopy revealed tenacious mucous plugs in the right main bronchus. The collapsed lung was successfully reinflated after bronchial lavage with a rigid bronchoscope, with the help of intermittent high-frequency jet ventilation (HFJV). The infant's mediastinal shift was reversed and the vital signs became stable. In our experience, rigid bronchoscopy combined with HFJV is a valuable diagnostic and therapeutic procedure for very small premature infants.

Bronchoalveolar Lavage↗

PubMed1995

The minimum effective dose of praziquantel in treatment of Hymenolepis diminuta in rats.

To determine the minimum effective dose of praziquantel against Hymenolepis diminuta in rats, 5.0 mg/kg, 2.5 mg/kg, 1.0 mg/kg, 0.5 mg/kg, 0.1 mg/kg, or 0.05 mg/kg praziquantel were given to each of five experimentally infected rats in six groups. Faecal samples from each rat were examined on ten consecutive days following treatment. The rats were killed and examined for worms on day 10. Based on the results of faecal examination and autopsy, the minimum effective dose of praziquantel against Hymenolepis diminuta in rats was determined to be 0.5 mg/kg.

Animals↗

PubMed1995

Morphological description of Taenia saginata asiatica (Cyclophyllidea: Taeniidae) from man in Asia.

In order to clarify the taxonomic status of the Taenia saginata-like tapeworm in East Asia, the morphological characteristics of the adult and cysticercus of classical T. saginata (American, Swiss and Poland strains) and the Taiwan Taenia were compared in the present study. The morphologic characteristics of these two parasites are very similar. The protoscolex of cysticercus of the Taiwan Taenia has a sunken rostellum while that of classical T. saginata has only an apical pit. In addition, the rostellum of the Taiwan Taenia cysticercus is usually surrounded by two rows of rudimentary hooklets. However, this structure is rarely found in classical T. saginata. Based on the results of molecular studies and morphological characteristics, the T. saginata-like tapeworm in East Asia represents a subspecies of T. saginata, named T. saginata asiatica.

Animals↗

PubMed1995

Hypersensitivity to mosquito bite: a case report.

Severe hypersensitivity to mosquito bites is very rare. A 18-year-old girl student has had multiple hemorrhagic bullae with atrophic scars on both limbs and left side of the face due to mosquito bites for 16 years. When she was seven years old, she noticed a severe local reaction with bloody bullae formation, chills, and fever several hours after the mosquito bite. The bullae developed into ulcers which finally became scars. This patient was confirmed to be hypersensitive to mosquito bites by the mosquito bite test. This case is the first record of mosquito allergy in Taiwan.

Adolescent↗

PubMed1995

Follow-up investigations on clinical manifestations after filariasis eradication by diethylcarbamazine medicated common salt on Kinmen (Quemoy) Islands, Republic of China.

From May to December 1993, a house-by-house survey was conducted on the changes in clinical manifestations of filariasis among 814 pre-control mf carriers in 88 villages of five towns/districts on Kinmen Islands. Four hundred and sixteen (51%) pre-control mf carriers were examined physically with history taking. The rates of disappearance, improvement, no change, aggravation, and new occurrence were 72% (229), 6% (26), 14% (59), 6% (24) and 2% (8), respectively. The rates of disappearance and improvement were higher for the acute than for the chronic manifestations. However, these rates were also high for hydrocele and chyluria. These findings indicate that the acute manifestations disappear or greatly improve after filariasis eradication by a low dose of DEC medicated salt for a period of 6 months. However, the chronic ones remain unchanged or even aggravated to become one of the more important public health problems.

Acute Disease↗

PubMed1995

Review of taeniasis in Asia.

Although Asian Taenia is closely related to T. saginata, it is a genetically distinct entity and can be distinguished from the classical T. saginata. Man is the only definite host of this parasite. The domestic pig and wild boar in Taiwan as well as domestic pig in Korea have been determined to be the natural intermediate hosts. Moreover, the pig has been demonstrated to be the most favorable experimental intermediate host. The cysticerci are situated mainly in the liver. They are smaller than T. saginata cysticerci and have a shorter developmental period of four weeks. The scolex of Asian Taenia cysticercus is often armed with two rows of hooklets. The adult worm of Asian Taenia is shorter and has less number of segments than the classical T. saginata. Recently, results of polymerase chain reaction studies indicate that the Asian Taenia is much more closely related to T. saginata than other taeniid species. Therefore, it is appropriate to designate Asian Taenia as a new subspecies of Taenia saginata asiatica. People in the Asian-Pacific region acquired the infection by eating raw or undercooked meat and/or viscera of pigs. Human experimental infections have succeeded in confirming the life cycle of Asian Taenia and the transmission pathway of the infection. In addition, multiple infection occurs very often and the infection has a family pattern. "Discharge of proglottids" is the most important clinical manifestation which is also useful in the diagnosis. Praziquantel is the drug of choice. The infection of Asian Taenia can be prevented by avoiding to eat raw or undercooked meat and viscera of pigs in the endemic regions.

Asia↗