Biomedical subjects

Z Jin

Publications and source records attributed to Z Jin.

150 records · Page 9Linked to original sources

PubMedDate not supplied

Extractive fermentation for enhanced propionic acid production from lactose by Propionibacterium acidipropionici.

An extractive fermentation process using an amine extractant and a hollow-fiber membrane extractor to selectively remove propionic acid from the fermentation broth was developed to produce propionate from lactose. Compared to the conventional batch fermentation, the extractive fermentation had a much higher productivity ( approximately 1 g/(L.h) or 5-fold increase), higher propionate yield (up to 0.66 g/g or more than 20% increase), higher final product concentration (75 g/L or higher), and higher product purity ( approximately 90%). Meanwhile, acetate and succinate productions in the extractive fermentation were significantly reduced. The improved fermentation performance can be attributed to the reduced product inhibition and a possible metabolic pathway shift to favor more propionic but less acetic and succinic acid production. The process was stable and gave consistent long-term performance over the 1. 5-month period studied. The effects of propionate concentration, pH, and amine content in the solvent on the extractive fermentation were also studied and are discussed in this paper.

Fermentation↗

PubMedDate not supplied

Application of Raney nickel to measure adducts of styrene oxide with hemoglobin and albumin.

Adducts of styrene 7,8-oxide (SO) with the blood proteins, Hb and albumin (Alb), were measured following treatment of the proteins with Raney nickel (Ra-Ni) to cleave 2-phenylethanol, which was subsequently assayed. Internal standards were prepared by modifying Hb and Alb with 4-methyl-SO to produce similar adducts. In a preliminary experiment with human blood, which had been modified with [14C]SO in vitro, it was determined that Ra-Ni released 6% of the total binding to globin and 76% of the total binding to Alb. Since Ra-Ni primarily cleaves covalently-bound sulfur species, this suggests that much more binding to human serum Alb occurred at a free cysteine residue than to human Hb. The overall rate of reaction of SO at 37 degrees C in vitro had a half-time of 0.70 h in human blood and of 0.36 h in blood from Sprague-Dawley rats. Adducts of SO with Hb and Alb were measured following SO modification of blood from humans and rats in vitro at 37 degrees C. Slopes of the linear relationships between adduct level and SO concentration allowed the following second-order rate constants [(L/mol of protein)/h] to be estimated: rat Hb, 72; human Hb, 2.4; rat Alb, 63; human Alb, 32. These rate constants show that intrinsic reactivity of SO toward the cysteine residue of human Hb is much lower than that of rat Hb or of Alb from either species. Adducts of Hb and Alb were also measured following administration of both SO and styrene to rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Elevation of serum albumin levels in nagase analbuminemic rats by allogeneic bone marrow cell transplantation.

We investigated the feasibility of correcting the congenital absence of albumin in Nagase analbuminemic rats (NARs) by allogeneic bone marrow cell transplantation (BMT). Seven-week-old male NARs were used as recipients, and 6- to 8-week-old male Sprague-Dawley (SD) rats were used as allograft donors. NARs were divided into three groups: a BMT group (n=10) in which bone marrow cells were infused into the liver; a hepatocyte transplantation (HCT) group (n=8) in which hepatocytes were transplanted into the liver, and a control group (n=8) in which PBS was injected into the portal vein. Serum albumin levels were measured as an indicator of the function of the grafted cells, and the phenotypic characteristics of the engrafted cells in the recipient's liver were assessed with immunohistochemical and immunofluorescence techniques. At 8 weeks after cell transplantation, the serum albumin levels of the BMT group and HCT group were significantly higher than in the control group. The hepatocyte-like cells derived from bone marrow cells expressed albumin in liver of the NARs. According to this result, bone marrow cells can differentiate into hepatocyte-like cells in vivo. The results show that BMT is an effective treatment for congenital analbuminemia in a rat model and suggest that allogeneic BMT can be used as an efficient therapy for hereditary metabolic diseases.

Acetylglucosaminidase↗

PubMedDate not supplied

An epidemiological analysis of leprosy from 1951-1996 in Sichuan.

Through the leprosy surveillance system established in 1990s the authors analysed the epidemiology of leprosy in Sichuan province from 1951 to 1996. By the end of 1996, the total number of registered cases was 32,772, the peak incidence rate (2.44/100,000) was in 1958. The annual average progressively decreasing speed (AAPDS) of the number of new cases, incidence rate, incidence rate among children, number of newly detected patients, detection rate, number of registered cases and registered prevalence rates were 4.7% (xg = 0.9534), 5.9% (xg = 0.9407), 7.4% (xg = 0.9263), 6.7% (xg = 0.9326), 8.1% (xg = 0.9195), 10.9% (xg = 0.8913) and 11.7% (xg = 0.8828) respectively. Among newly detected cases, the proportion of children gradually declined with an AAPDS of 2.9% (xg = 0.9712), but that of household contacts gradually increased, showing a gradual decline of source of infection. The multibacillary (MB) rate among new cases, newly registered cases and active cases also increased gradually. The MB rate among child cases was much lower than that among adults. The disability rates among newly registered cases tended to decline. The peak incidence was in the 20 to 35 years age group, the average age at onset being 31.92 years. Average age at onset gradually increased to 34.19 during 1991-1995. The average interval between onset of symptoms and diagnosis was 4.89 years and that had reduced gradually to 3.24 years during 1991-1995. The authors conclude that: (1) the epidemiological trend of leprosy in Sichuan province shows decline; (2) the case-finding activities have improved and intensified; but (3) the disability rate among newly detected cases is still high (> 20%) and the average delay in diagnosis is still too long, showing that early case finding is still not satisfactory.

Adolescent↗

PubMedDate not supplied

An electric model with time varying resistance for a pneumatic membrane blood pump.

To investigate the effects of an artificial heart and cardiac assist device on the cardiovascular system and determine the proper control method, an electrical model is an effective tool. An electric model with time varying resistance is proposed to represent a pneumatic membrane blood pump, by which the resistance of the valves in the pump is a function of time. The model is consistent over the whole cardiac cycle, and the important transitional processes between systole and diastole are considered. The calculated results based on this model are compared with the experimentally measured waveforms of the corresponding state-variables of a loaded pump, and the model parameters estimated using the least-squares criterion are compared with the measured physical values of corresponding functional parts. Results showed that this electric model is capable of representing a pneumatic membrane pump with quite satisfactory accuracy. They also showed that the transitional property of the valve resistance has a significant influence on the output characteristics of the pump.

Heart Valves↗

PubMedDate not supplied

Analysis of tear fluid by CE/LIF: a noninvasive approach for glucose monitoring.

Nanoliter volumes of human tear fluid were collected by means of a capillary tube without inducing tearing and were analyzed for glucose content. The tear fluid was subjected to two enzymatic reactions to generate a fluorescent compound that is proportional to the concentration of glucose in the sample. CE with laser-induced fluorescence (LIF) detection was used to monitor the fluorescent species generated, hence glucose in the tear samples. The reproducibility of the method for six different preparations was < 9% relative standard deviation (RSD). The procedure was compared with the glucose dehydrogenase method for the determination of glucose in blood before using it to determine glucose in tear fluid. Blood and tear samples were collected from six healthy human subjects. The results showed that the higher glucose content in tear samples is consistent with the higher glucose content in blood samples. The glucose concentration of the tear samples analyzed ranged from 128 to 166 microM, and that of blood ranged from 3.3 to 4.3 mM.

Blood Glucose↗