Control of the dehydration process in production of intermediate-moisture meat products: a review

IM meat products are produced by lowering the aw to 0.90 to 0.60. Such products are stable at ambient temperature and humidity and are produced in nearly every country in the world, especially in developing areas where refrigeration is limited or unavailable. Traditionally IM meats use low cost sources of energy for drying, such as sun drying, addition of salt, or fermentation. Products produced by different processes are of interest since they do not require refrigeration during distribution and storage. Many different IM meat products can be produced by utilizing modern processing equipment and methods. Production can be achieved in a relatively short period of time and their advantages during marketing and distribution can be utilized. Nevertheless, a better understanding of the principles involved in heat transfer and efficiency of production are still needed to increase efficiency of processing. A basic understanding of the influence of water vapor pressure and sorption phenomena on water activity can materially improve the efficiency of drying of IM meats. Predrying treatments, such as fermentation and humidity control, can also be taken advantage of during the dehydration process. Such information can lead to process optimization and reduction of energy costs during production of IM meats. The development of sound science-based methods to assure the production of high-quality and nutritious IM meats is needed. Finally, such products also must be free of pathogenic microorganisms to assure their success in production and marketing.

Molecular epidemiology of cytomegalovirus infection in kindergarten children

This study was conducted to determine the source of cytomegalovirus (CMV) excretion in children who had persistent viruria. A total of 287 children, ages 3-5 years, enrolled in two kindergartens were followed for 9 months, and 28.8% of 139 CMV-infected children were found to have shed virus persistently in urine for > or = 3 months. A polymerase chain reaction (PCR)-based method provided direct evidence to demonstrate differences in CMV strains shed by 32 persistent shedders selected at random. The glycoprotein B (gB) nucleotide regions of CMV were amplified and analyzed by restriction enzyme digestion. The CMV strains shed by most of these children showed different restriction profiles compared with strains from their playmates. It is considered that persistent reactivation of endogenous CMV is the most plausible explanation.

Difference in transcriptional activity of two homologous CYP21A genes

Steroid 21-hydroxylase (CYP21) deficiency is the major cause of congenital adrenal hyperplasia, a common genetic disease due to steroid imbalance. The main cause for the mutation of the CYP21A2 (c21B) gene is conversion of its nucleotide sequence to the neighboring homologous but nonfunctional c21A gene. In this report the transcriptional activities of the c21A and c21B genes have been analyzed. Transient transfection assays showed that transcription derived from the c21A gene was about 5-fold lower in strength than that of the c21B gene, although both sequences responded to cAMP normally in two adrenocortical cell lines. The normal response to cAMP could probably be attributed to equal activation of both genes by a transcription factor Nur77. The lower transcriptional activity of the c21A gene was attributed to sequence changes within 167 base pairs of the 5'-flanking region, which differs from the c21B gene by only four nucleotides at positions around -100. These four nucleotide changes render the c21A sequence to bind proteins less tightly than the -100 region of the c21B sequence, which binds proteins such as transcription factor Sp1 in electrophoretic mobility shift assays. The reduced transcription due to nucleotide changes at the regulatory region of the c21A gene, in combination with other mutations in the coding region, could play important roles in 21-hydroxylase deficiency.

Evolution of the feline-subgroup parvoviruses and the control of canine host range in vivo

A related group of parvoviruses infects members of many different carnivore families. Some of those viruses differ in host range or antigenic properties, but the true relationships are poorly understood. We examined 24 VP1/VP2 and 8 NS1 gene sequences from various parvovirus isolates to determine the phylogenetic relationships between viruses isolated from cats, dogs, Asiatic raccoon dogs, mink, raccoons, and foxes. There were about 1.3% pairwise sequence differences between the VP1/VP2 genes of viruses collected up to four decades apart. Viruses from cats, mink, foxes, and raccoons were not distinguished from each other phylogenetically, but the canine or Asiatic raccoon dog isolates formed a distinct clade. Characteristic antigenic, tissue culture host range, and other properties of the canine isolates have previously been shown to be determined by differences in the VP1/VP2 gene, and we show here that there are at least 10 nucleotide sequence differences which distinguish all canine isolates from any other virus. The VP1/VP2 gene sequences grouped roughly according to the time of virus isolation, and there were similar rates of sequence divergence among the canine isolates and those from the other species. A smaller number of differences were present in the NS1 gene sequences, but a similar phylogeny was revealed. Inoculation of mutants of a feline virus isolate into dogs showed that three or four CPV-specific differences in the VP1/VP2 gene controlled the in vivo canine host range.

Determination of the chlorofluorocarbon substitute 1,1,1,2-tetrafluoroethane (HFA-134a) in human and animal blood using gas chromatography with headspace analysis

A gas chromatographic procedure with headspace analysis and flame-ionization detection is described for the determination of the chlorofluorocarbon substitute 1,1,1,2-tetrafluoroethane (HFA-134a). A 0.5-2 ml sample of heparinized whole blood from a laboratory animal or human is added directly into a presealed headspace vial from which an equivalent volume of air has been removed. The internal standard 1,1,2,2-tetrafluoroethane is added and the sample frozen until analysis. Chromatographic separation is achieved using a PoraPlot Q porous-layer capillary column. The analytical range is 5.8-3298 ng/ml when 2-ml human blood samples are used. The concentration range of the calibration curve can be easily adapted to accommodate the concentrations expected in either pharmacokinetic or toxicokinetic studies. Automation of the assay permits the maximum number of samples to be processed in a day.

Comparison of the genetic variation in type 1 dengue virus isolates in Taiwan, 1987-1992

In this study, the genetic variation of eight dengue-1 strains isolated in Taiwan from 1987 to 1992 (including two imported strains) were studied. A fragment of 490 nucleotides from the E/NS1 junction was amplified and studied by reverse transcription-polymerase chain reaction (RT-PCR) and vector cloning. By comparing the nucleotide sequences of these strains, it was found that local strains in Taiwan shared geographic similarity. The nucleotide differences among local strains were less (0.61% to 2.24%) than the differences between imported strains and other strains (2.04% to 4.29%). The differences of nucleotide sequences between local strains and the prototype remain constant (5.10%-5.29%). However, the differences in nucleotide sequences between imported strains and the prototype ranged from 3.89% to 7.14%. Since the point mutations occurred in the wobble position of the codon, only conserved changes resulted in the amino acid among the isolates.

Weather and stroke in a subtropical area: Ilan, Taiwan

BACKGROUND AND PURPOSE

The aim of this study was to clarify the association of weather and stroke occurrence in a subtropical area in Ilan, Taiwan.

METHODS

We studied 517 patients with stroke (date of onset, January 1 to December 31, 1991) in Poh-Ai Hospital and St Mary's Hospital: 316 patients (61.1%) with cerebral infarction, 170 (32.9%) with intracerebral hemorrhage, and 31 (6.0%) with other types of stroke. The daily occurrence of cerebral infarction and intracerebral hemorrhage was analyzed and correlated with three major meteorologic factors: air temperature, air pressure, and relative humidity.

RESULTS

The occurrence of cerebral infarction was rather uniform in all kinds of weather. The occurrence of intracerebral hemorrhage was approximately twice as great on cold days (0.71 case per day) and high-pressure days (0.73) as on warm days (0.31) and low-pressure days (0.39) (P < .005 by chi 2 test). When a linear regression model was used to test whether air temperature or air pressure had more influence on intracerebral hemorrhage, only air temperature showed a significant effect. Regarding intracerebral hemorrhage, the relative risks of cooler and median temperature days versus warmer days were 18.5 and 5.1, respectively.

CONCLUSIONS

Intracerebral hemorrhage but not cerebral infarction occurs more frequently on cooler days, with a dose-response relationship, in Ilan, Taiwan.

Cytomegalovirus infection and viral shedding in the genital tract of infertile couples

The prevalence of cytomegalovirus (CMV) infection and viral shedding in infertile couples in Taiwan and its role in infertility were studied. Two hundred fifty couples were enrolled in this study. Anti-CMV IgG was measured in serum samples from these infertile couples. Viral shedding examined by DNA hybridization was detected in semen from the husband and cervical mucus from the wife. Anti-CMV IgG was detected in 249 (99.6%) of the 250 male serum samples and in 247 (98.9%) of the 250 female serum samples. Viral shedding was detectable in 83 (33.5%) of 248 semen samples and 83 (33.7%) of 246 cervical mucus samples by dot-blot DNA hybridization assay. Semen quality was not apparently affected by the existence of viral shedding. The co-shedding rate in semen and cervical mucus was high (15.9%). It is concluded that the seroprevalence and genital tract viral shedding were relatively high in infertile couples in Taiwan. Viral shedding did not affect the semen quality. Nevertheless, screening of donor semen is recommended.

Stroke incidence in Ilan, Taiwan

The purpose of this community hospital-based study of stroke was to assess the incidence rate of cerebral infarct, cerebral hemorrhage, and subarachnoid hemorrhage in a well-defined region of South Ilan. A prospective stroke registry was established at the two regional general hospitals serving about 184,000 inhabitants. From January to December 1991, a total of 258 stroke events were registered. Computed tomography was done in 99% of the stroke cases. The mean age for first-ever stroke in the region was 66.1 +/- 12.2 years. The annual incidence rates per 1,000 population for first-ever cerebral infarct in the respective age groups were 0.75 (45-54 years), 1.59 (55-64 years), 5.24 (65-74 years) and 8.01 (> or = 75 years). The incidence rates per 1,000 population for first-ever cerebral hemorrhage in the respective age groups were 0.52 (45-54 years), 1.19 (55-64 years), 1.05 (65-74 years) and 2.91 (> or = 75 years). The incidence rates per 1,000 population for first-ever subarachnoid hemorrhage in the respective age groups were 0.17 (45-54 years), 0.20 (55-64 years), 0.12 (65-74 years) and 1.21 (> or = 75 years). The age-specific incidence rate for first-ever stroke in the group aged 45 to 54 years observed in this study is higher than that in Western countries. The age-adjusted incidence rate for cerebral hemorrhage is significantly higher than that in Caucasians and is similar to that reported in Japan from 1974 to 1983.

[Drug resistance and plasmid analysis in Pseudomonas aeruginosa]

One hundred and ninety seven strains of Pseudomonas aeruginosa were isolated from urine (59 strains), wound pus (60 strains), sputum (30 strains), stool (30 strains) and eye discharge (18 strains) at Kaohsiung medical College Hospital. These strains were serotyped with antisera against O antigens and tested with twelve different antimicrobial agents. The results showed that the most frequently isolated strains were serotype E (41.1%), followed by serotype B (20.3%), serotype F (10.7%) and serotype L (9.1%). In in vitro susceptibility testing, all isolated strains were resistant to chloramphenicol and tetracycline. Otherwise, these isolates were highly susceptible to ceftazidime (95.4%), enoxacin (89.3%) and piperacillin (87.8%). The isolates from urine exhibited more multiple drug resistance patterns than those of other specimens. When plasmid content was analysed from pseudomonas aeruginosa, only 15.2% (30/197) of isolates carried plasmids. By conjugation, transformation and mobilization experiments, it was shown that 13.3% (4/30) of plasmid carrying strains contained R plasmids.

Humoral immune responses and cytomegalovirus excretion in children with asymptomatic infection

Forty-two seropositive children aged 3 to 5 years attending a kindergarten were followed up for 1 year in order to examine the relationship between humoral immunity and cytomegalovirus (CMV) excretion status. Anti-CMV antibodies were measured at the beginning and end of the study by enzyme-linked immunosorbent assay, neutralizing antibody test, and immunoblot techniques. Among these children, 32 persistently shed virus in urine, 2 intermittently shed CMV, and 4 experienced reactivation during the study. Virus was never isolated from 4 seropositive children. The level of anti-CMV IgG antibody in seropositive children who remained nonshedders was significantly higher than in children who shed virus during follow-up. On immunoblots, all seropositive nonshedders reacted to a CMV-specific 65 kD antigen, whereas most shedders (80%) did not. These findings suggest that humoral immunity plays a role in controlling persistent CMV infection in children with asymptomatic infection. However, the humoral immunity measured by the neutralizing test and the presence of antibodies against CMV-specific envelope antigens (116 kD/55 kD) apparently play a limited role in modifying persistent excretion and regulating reactivation of latent CMV. Immune evasion by CMV to block these antigens may explain these results.

Comparative pharmacokinetics of morning and evening doses of once-a-day theophylline capsules

The objective of this study was to determine if the theophylline diurnal variation that has been observed primarily between morning and evening doses of twice-a-day products could be overcome by a once-a-day formulation. Eighteen healthy, nonsmoking, adult male subjects were given 900-mg theophylline doses as three 300-mg once-a-day theophylline capsules in the morning or evening for 5 days in a single-blind fashion. Matching placebo capsules were administered midway between each dose of active drug. Predose theophylline serum levels on day 3-6 were statistically equivalent within each treatment, indicating that approximate steady-state conditions were achieved by day 3. Mean serum level profiles over the 24-h interval following the active dose on day 5 were almost superimposable for the morning and evening treatments. All pharmacokinetic parameters were equivalent between the treatments, except for the time to peak serum level (Tmax), which was significantly shorter for the morning dose. Given the flatness of the serum level curves for both treatments, the Tmax difference was judged to be clinically unimportant. A small peak-trough level fluctuation of about 50% was seen with each treatment. We conclude that by designing a dose form in which drug release was the rate-limiting step in drug absorption, the diurnal variation commonly associated with theophylline formulations may be eliminated.

Cervical cytomegalovirus infection in prostitutes and in women attending a sexually transmitted disease clinic

This study aimed to determine the frequency of, and to define factors associated with, cervical shedding of cytomegalovirus (CMV) in highly sexually active women (licensed prostitutes) and in women attending a sexually transmitted disease (STD) clinic. Cervical specimens obtained from 195 licensed prostitutes and 187 STD patients aged 17-50 years were compared for the presence of cervical CMV with specimens from 70 women of the same ages attending a gynecologic clinic. Cervical CMV was identified by the presence of a CMV-specific immediate-early gene sequence amplified by the polymerase chain reaction. Cervical CMV prevalences of 38.9% and 34.8% were found for licensed prostitutes and STD patients, respectively. These rates were significantly higher than the 24.3% cervical CMV prevalence for women attending the gynecologic clinic. The data suggest that frequent sexual contact with many sexual partners is responsible for the high frequency of cervical CMV observed in licensed prostitutes. The interaction between CMV and urogenital bacterial infections is a plausible explanation for the high cervical CMV prevalence in STD patients.

The altered expression of cytokeratin polypeptides in carcinomas of human bladder

After extraction in high salt buffers and Triton X-100, cytokeratin polypeptides could be isolated from normal epithelium and transitional cell carcinoma of the human bladder in the southwestern coast of Taiwan. The polypeptides were solubilized via lysis buffer, separated by two-dimensional gel electrophoresis, and identified by immunoblot. Five cases of normal epithelium expressed cytokeratin No. 5 (58 kd), 7 (54 kd), 18 (45 kd) and one case further expressed cytokeratin No. 19 (40 kd) in addition to the above cytokeratins. Combined patterns of cytokeratin polypeptides were observed among various Grades of transitional cell carcinoma of bladder. Comparing the patterns between the normal epithelium and the transitional cell carcinoma of bladder, 88% (14/16) of carcinomas expressed cytokeratin No. 8 (52.5 kd) and 63% (10/16) expressed No. 17 (46 kd), which were not seen in the normal epithelium. Some other cytokeratin polypeptides particular to carcinomas were No. 4 (59 kd), No. 10 (56.5 kd), No. 13 (54 kd) and No. 14 (50 kd) and were only present in less than 50% (ranging from 31-56%) of the examined specimens. Thus cytokeratin No. 8 and 17 could be helpful markers for diagnosis of bladder carcinoma.

[Characterization of trimethoprim resistance in Shigella]

Ninety-seven Shigella strains from 1982 to 1987 were isolated. When these isolates were tested with minimal inhibitory concentrations of trimethoprim, twenty-two were found to be resistant. Among these, 10 were found to be S. flexneri, and 12 to be S. sonnei. In addition, all of these 22 isolates were found to have multiple drug resistance. In order to determine the type of dihydrofolate reductase (DHFR) genes in these 22 trimethoprim-resistant isolates, colony hybridization with probes representing types I, II, III and V DHFR, were used. The results revealed the presence of type I DHFR gene in all of these isolates. Further southern hybridization indicated that the type I DHFR gene was located on plasmids. In order to determine whether a trimethoprim resistant gene existed as a functional transposable element in these isolates, we used a specific probe to detect the prevalence of Tn7. However, no positive hybridization was found. The relationship between the trimethoprim resistant gene and integron is characterized by the fact that the integrase gene, in our study, was frequently found in all of the 22 resistant isolates. These results indicate that trimethoprim resistant genes might transfer among bacteria via site-specific integration.

Progressive alterations of cytokeratin expressions in the process of chronic arsenism

Recent studies of an endemic occurrence of chronic arsenism in a limited area on the southwest coast of Taiwan are focusing on its cytokeratin analysis in hopes of tracing the disease's biochemical expression. Specimens were obtained from uninvolved skin and arsenical cancers including Bowen's disease, basal cell carcinoma, and squamous cell carcinoma. In this study, we used two-dimensional polyacrylamide gel electrophoresis to analyse cytokeratin expression. Progressive alterations in cytokeratin expression were found in various skin lesions. These include an expression of K16 in the uninvolved skin; K16 and K6 in Bowen's disease; and K16, K6 and K17 in squamous cell carcinoma and basal cell carcinoma. In addition, we found that the K1 isoelectric variants shifted to more acidic forms with the complete absence of K1 in basal cell carcinoma. K16 expression in uninvolved skin indicates that it is nevertheless in a hyperproliferative status. K17 was expressed in squamous cell carcinoma and basal cell carcinoma, but not in Bowen's disease. The progressive impairment of phosphorylation of K1 and K2 in the process of chronic arsenism provides us with a suitable model for studying the biological significance of phosphorylation in intermediate filaments during chemical carcinogenesis.

Characterization of R plasmids from Shigella sonnei in Taiwan

Plasmids of 70MDa from 6 Shigella sonnei isolates originating in Kaohsiung, Taiwan were found. All of them encoded resistance to chloramphenicol and tetracycline. These plasmids belonged to the H II incompatibility group. The fertility inhibition property of plasmids was the fi- type. Restriction endonuclease analysis revealed the six plasmids all had identical restriction patterns with BamH I, Hind III and Nru I. All six plasmids carried the type I chloramphenicol acetyltransferase gene and the class B tetracycline resistance gene as determined by Southern hybridization with DNA probes of various antimicrobial resistance genes. The results demonstrated that S. sonnei isolates harboured the same R plasmid.

Cytomegalovirus recurrence in seropositive pregnant women attending obstetric clinics

To understand reasons for cytomegalovirus (CMV) recurrence, a cohort of 350 CMV-seropositive pregnant women attending obstetric clinics in Taiwan was examined for cervical or urinary CMV shedding. Urine specimens were collected from 350 women and cervical secretion specimens were collected from 220 women. We measured the association of various factors with CMV recurrence, which was defined as viral shedding identified by the presence of a CMV-specific gene sequence amplified by the polymerase chain reaction in seropositive individuals. CMV recurrence status was independently associated with a sexual activity composite variable, which was defined by three sexual activity indicators: age at first sexual intercourse, total years of sexual experience, and average frequency of sexual intercourse prior to pregnancy. Pregnant women with a history of genital tract infection were more likely than women without such history to experience cervical CMV recurrence. Similarly, pregnant women with previous urinary tract infections were more likely to experience urinary CMV recurrence. The findings indicate that multiple exposure to CMV by sexual activity prior to pregnancy is an important determinant of CMV recurrence during pregnancy.

[Epidemiological study of cerebrovascular disease in the Taiwan area: current status]

We reviewed the reported epidemiological studies on cerebrovascular disease in the Taiwan area and discussed the following advantages and drawbacks of different approaches to data acquisition and analysis of the results. 1) Analysis of the data from vital statistics is readily available, and gives adequate information for secular trends, but the reliability of death certificate and the accuracy of subtypes of cerebrovascular disease must be taken into consideration. 2) A series of patients based on hospital registration can provide detailed data about the clinical manifestation and subtypes of stroke; whereas selection bias among hospitals may distort some clinical profile, and patients who have not visited the hospital are not included. 3) A community survey can obtain representative distribution of diseases in a community, but it takes much manpower and cost. The diagnosis of stroke is not very reliable because of limited usage of computed tomography and insufficient participation by qualified neurologists. 4) A community based hospital study has the advantage of combining a hospital registry and a community survey. It is difficult to conduct this type of study in the current medical environment in Taiwan since the referral system has not been well established. 5) A study of the survivalship of stroke can provide valuable information about the natural course of cerebrovascular disease.

High rate of concurrent genital infections with human cytomegalovirus and human papillomaviruses in cervical cancer patients

A case-control study evaluated a possible association between infection with human papillomavirus (HPV) or cytomegalovirus (CMV) and cervical cancer. Seventy-eight patients with cervical cancer (cases) were compared with 55 age-compatible patients with uterine leiomyoma (controls). Genital CMV and HPV infections were diagnosed by polymerase chain reaction amplification of viral DNA in cervical tissues. Smoking, first coitus or pregnancy before age 20, multiple sex partners, history of multiple pregnancies, and frequent sexual intercourse were important factors associated with cervical cancer. Only 9% of the cases versus 29.1% of the controls did not have genital infection with either virus. Concurrent genital CMV and HPV infection was noted in 51.3% of the cases but in none of the controls. HPV infection alone occurred in 15.4% of the cases but in only 5.5% of the controls. CMV infection alone was associated with no increased risk for cervical cancer. These data suggest that a synergistic interaction may occur between these two viral infections in the oncogenesis of cervical cancer.

Cytomegalovirus excretion in pregnant and nonpregnant women

Cervical and urinary excretion of cytomegalovirus by Taiwanese women was identified by the presence of a cytomegalovirus-specific immediate-early gene sequence amplified by the polymerase chain reaction. Excretion rates during the first trimester of pregnancy resembled rates for nonpregnant women. As pregnancy proceeded, the cervical excretion rate increased from 13 to 40% and the urinary excretion rate increased from 1 to 13%.

Kinetics of absorption of a new once-a-day formulation of theophylline in the presence and absence of food

Two three-way crossover studies were done to characterize the drug release characteristics of Monospan (3M Pharmaceuticals, St. Paul, MN) capsules, a new once-a-day theophylline formulation. In the first study, 22 healthy males received single 450-mg doses of Monospan in the presence and absence of a high-fat breakfast; the same dose of Somophyllin (Fisons, Rochester, NY) immediate-release liquid was given to fasted subjects as a reference. The second study involved 29 healthy males given a single dose of 900 mg of Monospan in the presence and absence of the same high-fat meal; Theo-24 (G. D. Searle and Co., Skokie, IL) capsules were given to fasted subjects as a reference. The results of both studies showed that food did not affect the absorption of theophylline from Monospan; peak concentration, to and area under the serum concentration-time curve were all unchanged. The absorption rates were similar with both strengths and dietary conditions and showed that theophylline was absorbed slowly from Monospan at a constant rate (approximately 3.2%/h) over 24 h. Absorption continued past 24 h, and the extent of absorption from Monospan compared with that from each reference averaged 88% or higher. A good correlation (r > 0.980) was observed for Monospan between the amount absorbed in vivo and the amount released in the in vitro dissolution test, a result that demonstrates the precise rate control of Monospan. We conclude that Monospan is a suitable once-a-day formulation that can be taken without regard to food.

Cytomegalovirus transmission in special-care centers for mentally retarded children

This study aimed to determine whether special-care centers for mentally retarded children are high-risk settings for cytomegalovirus (CMV) transmission. Serum and urine specimens obtained from 311 mentally retarded children aged 3 to 12 in three centers were compared for CMV seropositivity and CMV viruria with specimens from 360 normal children of the same ages. A seropositivity rate of 73.5% and a viruria rate of 8.7% were found among the children attending special-care centers. These rates were significantly higher than the 59.2% seropositivity and 1.7% viruria found among normal children. By logistic regression analysis, it was shown that the prevalence of CMV viruria in the class/center was one of the most important determinants for acquiring CMV infection. The data suggest that acquisition of CMV from playmates or classmates occurs frequently in special-care centers and that horizontal transmission of virus is the most plausible explanation for the higher prevalence of CMV infection among mentally retarded children.

Multiple amino acids in the capsid structure of canine parvovirus coordinately determine the canine host range and specific antigenic and hemagglutination properties

Canine parvovirus (CPV) and feline panleukopenia virus (FPV) are over 98% similar in DNA sequence but have specific host range, antigenic, and hemagglutination (HA) properties which were located within the capsid protein gene. In vitro mutagenesis and recombination were used to prepare 16 different recombinant genomic clones, and viruses derived from those clones were analyzed for their in vitro host range, antigenic, and HA properties. The region of CPV from 59 to 91 map units determined the ability to replicate in canine cells. A complex series of interactions was observed among the individual sequence differences between 59 and 73 map units. The canine host range required that VP2 amino acids (aa) 93 and 323 both be the CPV sequence, and those two CPV sequences introduced alone into FPV greatly increased viral replication in canine cells. Changing any one of aa 93, 103, or 323 of CPV to the FPV sequence either greatly decreased replication in canine cells or resulted in an inviable plasmid. The Asn-Lys difference of aa 93 alone was responsible for the CPV-specific epitope recognized by monoclonal antibodies. An FPV-specific epitope was affected by aa 323. Amino acids 323 and 375 together determined the pH dependence of HA. Amino acids involved in the various specific properties were all around the threefold spikes of the viral particle.

The distribution of the DHFR genes in trimethoprim-resistant urinary tract isolates from Taiwan

Between July 1987 and June 1989, 1054 urinary isolates of enterobacteria from Kaohsiung, Taiwan were studied for their trimethoprim resistance. Trimethoprim resistance was defined as MIC greater than 4 micrograms/ml and high-level resistance by MIC greater than 1000 micrograms/ml. The incidence of trimethoprim resistance increased from 33.6% in 1987 to 42.1% in 1989. Among the resistant strains studied, 90% were resistant to high levels of trimethoprim. An increase in the proportion of resistant strains (33.9-46.3%) exhibiting high-level non-transferable trimethoprim resistance was noted. The distribution of the dihydrofolate reductase (DHFR) genes by colony hybridization in 374 trimethoprim-resistant isolates revealed the presence of type I and type V DHFR genes in most of these isolates (45.4% and 10.4% respectively). Type I was predominant in Escherichia coli whereas type V was frequently seen in Enterobacter spp. None showed homology with the type II and type III DHFR probe DNA. In addition, transposon Tn7 was present in 7.8% of 374 trimethoprim-resistant enterobacteria.

Mutations adjacent to the dimple of the canine parvovirus capsid structure affect sialic acid binding

The erythrocyte receptor on rhesus macaque erythrocytes used by canine parvovirus (CPV) for binding in hemagglutination (HA) was examined. Erythrocyte membrane proteins were electrophoresed and blotted to nitrocellulose and probed with [125I]-labeled CPV capsids, showing seven virus-binding proteins. Treatment of erythrocytes or isolated membranes with Clostridium perfringens neuraminidase virtually abolished virus binding. Binding was also affected by treatment with potassium periodate and inhibited by wheat germ agglutinin, but was not significantly affected by concanavalin A, peanut agglutinin, or soluble N-acetyl-neuraminlactose. A non-HA mutant of CPV failed to bind to erythrocytes or to blotted erythrocyte membrane proteins. The mutation was a single Arg-Lys difference of VP2 amino acid residue 377. The pH dependence of binding of the closely related feline panleukopenia virus was shown to result from a decreased binding in buffers with pH values of 6.8 or greater. The VP2 residues responsible for that difference have been shown to be 323 and 375. The sequences affecting binding were all adjacent to the dimple in the capsid, implicating that region of the capsid as the sialic acid binding site. The role of sialic acid in virus-host cell interactions was not defined, but the plaque sizes of the non-HA mutant and wild type CPV were indistinguishable.

Seroepidemiology of cytomegalovirus infection among children between the ages of 4 and 12 years in Taiwan

To determine risk factors responsible for primary cytomegalovirus (CMV) infection in Taiwan, samples of blood for antibody to CMV were obtained from 362 children aged 4 to 12 years: 58% were found to be positive for anti-CMV IgG antibody. Logistic regression analysis showed that seropositivity correlated with age, method of delivery, duration of breast feeding, and younger age of mother. Neither socioeconomic status nor crowded living conditions showed significant correlation with CMV seropositivity. Primary CMV infection in Taiwan appears to be less related to socioeconomic status shown in western countries, and, since the majority of pregnant women were seropositive in Taiwan, two of the major sources of primary CMV transmission are infected breast milk and the infected genital tract.

Molecular cloning and nucleotide sequencing of a novel aminoglycoside 6'-N-acetyltransferase gene from an R-plasmid of Salmonella typhimurium S24 isolated in Taiwan

A conjugative aminoglycoside resistance plasmid pST2 has been isolated from Escherichia coli K-12 14R525, which was mated with a clinical isolate of Salmonella typhimurium S24. A novel resistance gene of aminoglycoside 6'-N-acetyltransferase[AAC(6')] was cloned from plasmid pST2 on a 1,393 kilobase (kb) of SphI-SalI fragment into vector pACYC184 and pUC18. This novel AAC(6') gene in plasmid pST2 acetylated kanamycin, amikacin, dibekacin, tobramycin, gentamicin, netilmicin, and sisomicin. The complete nucleotide sequence of the novel AAC(6') gene and its neighboring sequences were also determined. Minicell experiments detected only one protein of 24.7 kilodaltons (kDa) translated from an open reading frame of the 618 base pairs (bp) gene.

Comparative absorption of atropine from a metered-dose inhaler and an intramuscular injection

The inhalation of atropine sulfate from a pressurized metered-dose inhaler was investigated in a nonrandomized four-period rising-dose study. Eight healthy, nonsmoking subjects received 1.7, 3.4, and 5.2 mg of atropine sulfate by inhalation and 1.67 mg of atropine free base (equivalent to 2 mg of atropine sulfate) by intramuscular (i.m.) injection. Serum atropine sulfate concentrations were measured over a 24-h period by gas chromatography/mass spectrometry. Mean serum concentrations increased nonproportionally as the inhaled dose increased. Mean peak concentrations were 4.9, 6.1, and 7.9 ng/ml for the inhaled doses and 8.4 ng/ml for the i.m. dose. Typical anticholinergic effects were seen after all doses.

[Secular trends in mortality for cerebrovascular diseases in Taiwan (1959-1989)]

Cerebrovascular disease (CVD) is predominantly a disease of the elderly, and its morbidity effects increase with advancing age. In Taiwan, the increasing proportion of the elderly, as a result of medical progress and improved health care in the past 30 years, is largely responsible for the apparent increase in the number of CVD deaths. From 1963 to 1981, CVD was the leading cause of death. The crude mortality rate (CMR) and age-specific mortality rate (ASMR) of CVD by sex were derived from vital statistical data from 1959 to 1989 in Taiwan. The age-adjusted mortality rate (AAMR) using the standard world population of WHO and the cumulative mortality rate (CUMR) from birth to less than 80 years of age were calculated. Before 1983, the total number of CVD deaths had increased steadily for 30 years. In 1989, the CMR was 76.6/100,000 in men and 67.7/100,000 in women. The highest AAMR was 158.5/100,000 in 1973 for men and 130.2/100,000 in 1972 for women, and the lowest AAMR was 91.3/100,000 in 1989 for men and 81.1/100,000 in 1972 for women. The highest CUMR was 26.3% in 1968 for men and 20.8% in 1972 for women, and the lowest CUMR was 14.5% in 1989 for men and 13.6% in 1989 for women. The AAMR and CUMR for both sexes reached a maximum in 1972 and began to decline thereafter. The declines in AAMR and CUMR were averaging 2%/yr for both sexes after 1972 and were averaging 5%/yr for men and 4%/yr for women after 1983. This declining trend in CVD deaths in Taiwan began later and has been slower than similar trends in Japan and the U.S.

Prevalence of transposons encoding kanamycin, ampicillin and trimethoprim resistance in isolates from urinary tract infections detected using DNA probes

Drug resistant Gram-negative bacteria causing urinary tract infections were collected. Kanamycin, ampicillin or trimethoprim-resistant strains were analyzed separately for the presence of Tn5, Tn3, or Tn7 by colony hybridization. Of these isolates, kanamycin-resistant transposons were present in 38.2% of 60 kanamycin-resistant isolates. A 3.3 kb fragment containing SacI-BamHI transposase of Tn3 and 42.6% showed a positive reaction in 129 ampicillin-resistant clinical isolates. Among the 75 trimethoprim-resistant isolates studied, 52% were shown to contain Tn7 when probed with a 1 kb BamHI fragment of Tn7. Results from Southern hybridizations demonstrated that these antibiotic resistant genes had been born on plasmids in some clinical isolates.

Spontaneous production of growth factors for human lymphocytes from a human papillomavirus type 18-contained foreskin fibroblast cell line

An immortalized fibroblast cell line, designated as CCFS-1/KMC, derived from human neonatal foreskin fibroblasts, contained human papillomavirus (HPV) type 18 DNA. Since this newly established cell line could spontaneously secrete activating factors for normal human blood lymphocytes, the synthesis and release of potent inflammatory cytokines from this cell line were checked. To determine the presence of cytokines in the supernatant collected from the cell line, tests by a cytokine-specific ELISA and a mitogenesis bioassay were done. The cell line could spontaneously produce several immunoreactive cytokines, such as tumor necrosis factor (TNF), interleukin 1 (IL-1) and interleukin 6 (IL-6). It also could stimulate the mitosis of human blood lymphocytes and Raji lymphoblast cell line. These cytokines were present in the same fraction of isoelectric points (pI) from 5.4 to 5.6. This study suggests that non-immune bystander cells may exert immunomodulatory effect on the immune cells via the production of potent inflammatory cytokines during viral infection.

Drug resistance and plasmid profile of shigellae in Taiwan

One hundred and twenty-eight shigella strains isolated from newborn and infant human faecal specimens at Kaohsiung Medical College Hospital in Taiwan were serogrouped, serotyped and examined for drug-resistance patterns and for the presence of plasmids. Forty-seven per cent of the isolates were found to belong to the Shigella sonnei serogroup, 41% to the S. flexneri group, 9% to the S. boydii group and 3% to the S. dysenteriae group. The serotype with the greatest number of strains was S. sonnei I. (29%) followed by S. flexneri 1 (27%). Each strain was tested for resistance to 11 antimicrobial agents. Eight-eight per cent of the strains were resistant to tetracycline, 87% to chloramphenicol, 84% to streptomycin, 52% to ampicillin, 25% to nalidixic acid, 29% to kanamycin, 11% to cephalothin, 11% to neomycin, 10% to cotrimoxazole, 1% to amikacin and none to gentamicin. The most prevalent resistance pattern was ApCmSmTc (28%). Clinical isolates demonstrating multiple resistance were found to harbour a large transmissible plasmid of 45-75 MDa while isolates without multiple resistance did not. Two large virulence plasmids of 123 and 110 MDa were found in 12 strains of S. flexneri and 4 strains of S. sonnei phase I. Small plasmids of 4.5, 4.2, 3.5, 2.8, 2.5. 2.0 and 1.5 MDa were also present in all strains. These small plasmids were species specific and can be used as marker plasmids to identify species.

Characterization of an immortalized human cell line derived from neonatal foreskin diploid fibroblasts

A new human skin cell line, designated as CCFS-1/KMC, immortalized from human neonatal foreskin diploid fibroblast cells, has been subcultured successfully in vitro for more than 500 passages. This anchorage-dependent cell line possesses many common features of transformation such as morphological and cytoskeletal changes, hypotriploidy, infinite lifespan, increasing plating efficiency and saturation density, and decreasing serum requirement and population doubling time. Human papillomavirus (HPV) type 18 DNA was detected in the cell line before and after immortalization by the polymerase chain reaction (PCR) method. Tumorigenicity, however, was not demonstrated in vivo. The isoenzyme activity of the cell line shows activation of a placental form of alkaline phosphatase and a changing lactate dehydrogenase isoenzyme pattern that is different from transformation by carcinogens. Class I HLA and class II HLA antigens are constitutively expressed on this skin cell line. Here we report that these immortalized human fibroblasts derived from neonatal HPV-18-DNA-contained diploid fibroblasts possess double minute chromosomes (DMs), a karyotypic aberration usually found in cancer cells.

Rapid detection of hog cholera virus in tissues by the polymerase chain reaction

A rapid method for the detection of hog cholera virus (HCV) in infected tissues, using polymerase chain reaction (PCR) was developed. Total RNA isolated from HCV-infected tissues was reverse transcribed with AMV reverse transcriptase and the resulting complementary DNA was amplified by Taq DNA polymerase in the presence of two HCV-specific primers. The amplified DNA fragment was detected by agarose gel electrophoresis. The sensitivity of this method was at 10(4) TCID50 of HCV. The sensitivity increased approximately 1000-fold when the DNA was reamplified with a set of nested primers. DNA sequencing analysis of the PCR products revealed that the HCV sequence amplified from a local field isolate was highly homologous to the HCV Alfort strain. This method may be useful for pathological and epidemiological studies of HCV in pigs.

Characterization of cDNA encoding the mouse hepatic triglyceride lipase and expression by in vitro translation

A cDNA coding for the mouse hepatic triglyceride lipase has been isolated from a mouse liver cDNA library. The nucleotide sequence of the cDNA shows an open reading frame encoding a polypeptide of 510 amino acids that is 91.5% and 86% homologous to rat and human hepatic lipase, respectively. The most drastic protein sequence divergence is found at the carboxyterminal end which was speculated to harbour one heparin-binding site. By in vitro translation of cRNA in the presence of pancreatic membranes the hepatic lipase was shown to be glycosylated and to have an electrophoretic mobility of 53 kDa.

Acetylcholine receptor-specific T-lymphocyte clones in the normal human immune repertoire: target epitopes, HLA restriction, and membrane phenotypes

Potentially autoimmune T-lymphocyte lines specific for the nicotinic acetylcholine receptor of the neuromuscular junction have been isolated previously from patients with myasthenia gravis. We report on the isolation and expansion of T cells specific for the acetylcholine receptor of Torpedo californica or for a recombinant mammalian acetylcholine receptor alpha chain peptide (X4), from the peripheral blood of 11 healthy donors. Two major T-cell epitopes, located between amino acid positions 44-104 and 141-172, were identified using a panel of overlapping mammalian alpha chain fusion proteins. Most T lines recognized the acetylcholine receptor epitopes in the molecular context of HLA-DR molecules. Unexpectedly, all the T. californica acetylcholine receptor-specific T lines obtained from one DR4 (DRw53), DQw3 donor and two DR4, w8 (DRw53), DQw3 donors were restricted by DRw53 product(s). Using DR gene-transfected L cells as antigen presenters, in 4 lines, a close relationship between the recognized epitope and the restricting DR element was revealed. The membrane phenotype of the T. californica acetylcholine receptor-and X4-specific T lines was predominantly CD4+CD8-, with some CD4+CD8+ components. It did not significantly differ from that of control, tuberculin purified protein derivate-specific T lines raised from the same donors. These findings are in harmony with previous ones demonstrating the presence of potentially autoimmune T-lymphocyte clones within normal immune repertoires.

Analysis of an Escherichia coli dnaB temperature-sensitive insertion mutation and its cold-sensitive extragenic suppressor

An Escherichia coli mutant, ts121, was isolated following random insertional mutagenesis using phage lambda Mu transposition. The mutant phenotype includes inability to form colonies at temperatures above 38 degrees C and inability to propagate phage lambda at all temperatures. A lambda i434 cI- (ts121)+ transducing phage was isolated on the basis of its ability to form plaques on ts121 mutant bacteria. Using this transducing phage, it was shown through complementation and protein analyses, that the ts121 mutation is located in the dnaB gene. The exact insertion event was identified by polymerase chain reaction amplification of the DNA sequences containing the insertion junction. The mutational insertion event in ts121 was mapped precisely between base pairs 1514 and 1515 of the dnaB gene. This result predicts that the mutant dnaB protein has lost its six terminal amino acids. The reading frame shifts into Mu-specific DNA sequences resulting in an additional 20 amino acid residues. The E. coli wild type dnaB protein participates in host replication and interacts with lambda P protein to initiate phage lambda DNA replication. Our results demonstrate that the extreme carboxyl end of the dnaB protein is required for productive interaction with the lambda P replication protein at all temperatures, and is important for dnaB function at temperatures above 38 degrees C. Cold-sensitive extragenic suppressors of the ts121 mutation were isolated on the basis of their ability to restore colony formation at 42 degrees C. One of these extragenic suppressors was mapped at 54 min on the E. coli genetic map and localized to the suhB gene, whose product may affect the expression of a number of genes at the translational level.

Flecainide excretion in human breast milk

Healthy human volunteers who intended not to breast feed were placed on a regimen of 100 mg oral flecainide every 12 hours for 5 1/2 days beginning 1 day after parturition. Milk and blood samples were collected during the dosing period and for 2 days after the last dose. Concentrations of flecainide in milk and plasma were assayed by HPLC. Apparent steady-state levels of flecainide in both milk and plasma were achieved in most cases by day 4 of the study. Highest daily average concentration of flecainide in milk ranged from 270 to 1529 ng/ml for the 11 subjects. Mean +/- SD milk to plasma flecainide ratios were 3.7 +/- 3.5, 3.2 +/- 2.3, 3.5 +/- 2.1, and 2.6 +/- 0.7 on study days 2, 3, 4, and 5, respectively. After the last dose of flecainide, peak milk levels of the drug occurred at 3 to 6 hours and then declined monoexponentially. The half-life for elimination of flecainide from milk was 14.7 +/- 3.5 hours and is very similar to the plasma elimination half-life of flecainide in healthy human subjects. The mean milk to plasma ratios for flecainide after the last dose were 2.3 +/- 1.0 and 2.9 +/- 1.1 at 24 and 48 hours after the dose, respectively. Based on the pharmacokinetics of flecainide in infants, the expected average steady-state plasma concentration of flecainide in a newborn infant consuming all of the milk production of its mother (approximately 700 ml/day) would not be expected to exceed about 62 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth and characterization of normal human keratinocytes in F12 serum-free medium

In a F12 medium supplemented with epidermal growth factor (20 ng/ml), insulin (5 micrograms/ml), transferrin (5 micrograms/ml), hydrocortisone (1 microM), cholera toxin (40 ng/ml), endothelial cell growth supplement (15 ng/ml) and retinoic acid (1 x 10(-7) M) on Vitrogen coated culture dishes, normal adult and newborn human foreskin keratinocytes were cultured for 4- and 2-time with population doublings (PD) accumulated as 8 and 12, respectively. The cells grown in this medium possessed a basaloid, undifferentiated and hyperproliferating nature, with a population doubling time of about 24 hours at early passage. Between the 1st and 2nd subcultures, cell proliferation was the most active. Delaying the time of first subculture lowered the rate of cell proliferation. The keratin of the cultured cells was studied by immunoblotting and revealed the presence of permanent keratin markers of the human skin (AE1 50 kDa and AE3 58kDa) as well as a relatively high intensity of a proliferating marker (AE1 48 kDa) and a relatively low intensity of a differentiation marker (AE3 67 kDa).

The subtypes, distribution and location of human papillomavirus DNA in genital warts and genital Bowen's disease--a study using in situ DNA.DNA hybridization

The aim of this study is to investigate the difference in subtypes and distribution of human papillomavirus (HPV) between the benign pathological condition- Genital wart (condyloma acuminatum, verruca- like lesion and papular lesion) and genital Bowen's disease (Bowenoid papulosis, Mollucum contagiosum with Bowenoid papulosis and Condyloma acuminatum with verruca- like lesion and pathological bowenoid change) of genitalia by in situ DNA.DNA hybridization. In situ DNA.DNA hybridization was performed by hybridizing the RNAse treated and denatured frozen skin section with 3H-labeled HPV 6, 11, 16 and 18-DNAs probes and then developed autoradiogram on a glass slide. The results reveal that: (1) The benign cases are strongly associated with HPV 6/11, while the bowenoid cases are associated with HPV 16/18, indicating 16 positive in 24 cases and 3 positive in 5 cases respectively; (2) Four of sixteen benign cases were doubly infected with HPV 6/11 and 16/18; and 2 of 2 bowenoid cases were infected with HPV 16/18 only (3) In benign cases, HPV distributes through the upper third of epidermis and in bowenoid cases, HPV scatters throughout the whole epidermis including parabasal layers. These findings may indicate that the subtypes of HPV, the interaction of weak oncogenic virus (HPV 6/11) and strong oncogenic virus (HPV 16/18) and the presence of HPV on proliferating cells (parabasal layers) all play a part in oncogenicity. The detectability of HPV 6/11 DNA in both the nucleus and cytoplasm indicate that: 1). In situ DNA.DNA hybridization is a more sensitive method than the immunological detection of capsid antigen. 2). In addition to the nucleus, the cytoplasm is a site through which HPV 6/11 virus should pass during their life cycle. Using PEG hybridization mixture, it was revealed that 6 of the 6 HPV 6/11 positive condyloma acuminata harbored HPV 6. This result indicates that the subtype of HPV determine the gross morphology of skin lesion.

Factor analysis for the presence of serum HBV DNA in chronic hepatitis B virus infection

To elucidate the role of HBeAg and other influential factors for the presence of serum HBV DNA and their interactions, serum HBV DNA was examined in 68 patients with chronic HBV infections and 23 HBsAg negative persons by molecular hybridization. Based on the univariate analysis, the positive rate of HBV DNA was higher in patients with HBeAg (31/43, 72.1%) than in patients with anti-HBe (5/22, 22.7%) with an odd ratio of 8.78. The positive rates of HBV DNA between men and women were not significantly different, and the positive rates of HBV DNA were not related to the SGPT levels. The mean age of patients without HBV DNA was higher than that of patients with HBV DNA (p value less than 0.025), and the positive rate and concentration of HBV DNA were decreased with increasing age (p value less than 0.005). The positive rates of serum HBV DNA among different histological changes were not statistically different. However, the discordance of HBV DNA and HBeAg/anti-HBe was increased when the liver parenchymal damage became severe (p less than 0.05). Only 5 patients were anti-D positive and 3 of them had serum HBV DNA. To exclude interactions of the influential factors, multivariate analysis was also performed. HBeAg was the only significant factor for the presence of serum HBV DNA when logistic regression was used (p less than 0.001). The age was an important factor when the concentration of serum HBV DNA was considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of cytotoxicity and R-plasmid in Salmonella krefeld

From 1981 to 1984, 254 isolates of Salmonella krefeld were isolated from newborns and infants with acute gastroenteritis in southern Taiwan. All the crude enterotoxin preparations of S. krefeld caused the cytotoxic elongation reaction in Chinese hamster ovary K1 (CHO-K1) cells. Cytotoxic enterotoxin was also produced by S. krefeld inducing Vero cells to round up and appear partially detached from the culture plate. It was noted that S. krefeld showed internalization and multiplication in CHO-K1 cells. S. krefeld exhibited 12 different resistant patterns. And the predominant patterns were found to be resistant to kanamycin and ampicillin (Ka-Amr), and resistant to kanamycin, ampicillin, chloramphenicol and tetracycline (Ka-Am-Cm-Ter). It was found that two distinct plasmids of 34 megadalton (Md) and 120 Md were commonly present in these strains. S. krefeld haboured 34 Md and 120 Md R-plasmid, which conferred resistance to Ka-Amr and Ka-Am-Cm-Ter, respectively. From the resistance transferred patterns, Ka-Amr was the most common resistance among transconjugants. The frequency of transfer of the 34 Md R-plasmid (2.71 x 10(-3) transconjugants/donor cell) from S. krefeld to E. coli K-12 14R525 was 20 times higher than that of the 120 Md R-plasmid (1.48 x 10(-4) transconjugants/donor cell). In analysis of the restriction endonuclease digest of the 34 Md plasmid obtained from different bacterial sources, their specific identical DNA fragment pattern suggested that the outbreak infection due to S. krefeld had a common origin.