Sequence analysis of the ROB-1 beta-lactamase gene from Actinobacillus pleuropneumoniae

The ROB-1 beta-lactamase gene from Actinobacillus pleuropneumoniae was cloned and sequenced. The structural gene encodes a 305 amino acid polypeptide. The ROB-1 beta-lactamase gene sequence is identical to that derived from Pasteurella haemolytica and only one amino acid different from that of Haemophilus influenzae, suggesting that they are derived from the same ancestor, and transformed from one to another.

Tyrosine-specific protein phosphorylation in response to anti-CD3 antibody is diminished in old mice

Antiphosphotyrosine immunoblots were used to characterize phosphotyrosine-containing proteins (PY-PPNs) in anti-CD3 stimulated murine T lymphocytes. Activation led to increased phosphorylation of three PY-PPNs (MWs of 120, 80, and 40 kD) within 2 minutes, and maximal phosphoprotein levels were sustained for at least 30 min. There was a progressive decline with age in the responses of these three PY-PPNs to anti-CD3 stimulation, and some 20-23-month-old mice were virtually nonresponsive. A second group of PY-PPNs was present in unstimulated cells and not affected by anti-CD3 treatment or by age. Responses to Con A and to an antibody to the T-cell receptor were also found to be lower in old mice. Our data show that the pattern of tyrosine-specific phosphorylation in normal murine T cells is similar but not identical to patterns previously defined in murine tumor T-cell lines, and that T cells in old mice have defects in tyrosine-specific phosphorylation that could contribute to their diminished responsiveness to mitogenic stimuli.

Cyanobacterial metallothionein gene expressed in Escherichia coli. Metal-binding properties of the expressed protein

The recently isolated Synechococcus gene smtA encodes the only characterised prokaryotic protein designated to be a metallothionein (MT). To examine the metal-binding properties of its product the smtA gene was expressed in Escherichia coli as a carboxyterminal extension of glutathione-S-transferase. The pH of half dissociation of Zn, Cd and Cu ions from the expressed protein was determined to be 4.10, 3.50, 2.35, respectively, indicating a high affinity for these ions (in particular for Zn in comparison to mammalian MT). E. coli expressing this gene showed enhanced (ca. 3-fold) accumulation of Zn.

Expression of the pea gene PSMTA in E. coli. Metal-binding properties of the expressed protein

The pea (Pisum sativum L.) gene PSMTA has an ORF encoding a predicted protein with sequence similarity to class I metallothioneins (MTS). To examine the metal-binding properties of the PSMTA protein it has been expressed in E. coli as a carboxyterminal extension of glutathione-S-transferase (GST). Metal ions were associated with the expressed protein when purified from lysates of E. coli grown in metal supplemented media. The pH of half-dissociation of Zn, Cd and Cu ions from the recombinant fusion protein was determined to be 5.35, 3.95 and 1.45 respectively, compared with equivalent estimates of 4.50, 3.00 and 1.80 for equine renal MT.

A morphological study of primary pulmonary hypertension--an analysis of six autopsy cases

Six typical autopsy cases of primary pulmonary hypertension are reported. The histopathological features were as follows: medial hypertrophy of the muscular pulmonary arteries, muscularization of arterioles, internal fibrosis and fibroelastosis of muscular pulmonary arteries with typical "onion-skin" configuration, fibrinoid necrosis of the media or necrotizing arteries of muscular pulmonary arteries, and formation of highly characteristic plexiform lesions and dilatation lesions. It is thought that the plexiform lesions seen in all six cases represent morphological changes resulting from pulmonary hypertension rather than congenital abnormalities or thromboembolism.

Decomposition of nonlinear non-Gaussian process and its application to nonlinear filter and predictor design

An approach for decomposing of a Nonlinear Non-Gaussian Process (NNGP) is presented. A set of adjoin processes alpha's are first constructed based on the orthogonal principle so that the linear and nonlinear part of the process can be completely separated by a correlation operation without the statistical assumption on the process (i.e., it is not necessarily a Gaussian Process). The linear and nonlinear filters or predictors can then be designed and implemented independently and the consistency of parameters is guaranteed. An algorithm is given for a second order nonlinear process, and it can easily be extended to higher order cases if necessary. The method is first demonstrated by applying it to a nonlinear filter design problem, i.e., system identification. Finally, the necessity of a proposed decomposition procedure is proven by applying it to an example in which the parameters of a signal model are extracted from a version which is distorted due to the nonlinearity of the channel.

Epithelial lining of sinus tracts associated with periapical disease: an immunocytochemical study using monoclonal antibodies to keratins

We examined 30 specimens of mucosal sinus tracts arising in association with periapical inflammation. Immunocytochemistry and a panel of monoclonal antibodies to keratins were used to demonstrate the epithelial lining and its pattern of keratin expression. Half of the specimens were found to have an epithelial lining that was continuous with the mucosal epithelium and showed various degrees of extension into the sinus. The presence of an epithelial lining appeared to correlate with the duration of the sinus tracts. The immunostaining patterns of the epithelial linings were similar to those of the mucosal epithelium near the sinus opening although some differences were found. Proliferating strands of epithelium, presumably derived from the rest of Malassez, were observed deep in the tissues but were not continuous with the epithelial lining. The results suggest that the epithelial lining of sinus tracts is derived not from epithelial rests in the periapical region but from the mucosal epithelium adjacent to the opening of the sinus tract and that the observed changes in the pattern of keratinization are due to the influence of inflammation or of the connective tissue substrate.

[A survey of nosocomial infection by Salmonella typhimurium]

140 cases of infections by Salmonella typhimurium were studied from June 1987 to the end of 1988. Among those patients 56% of the cases were hospital-acquired. The nosocomial infection rate of the disease in the hospital was 14.6%. The majority of these cases were found in infants and young children. The sources of infections were the sporadic out patients. Improper isolation and disinfection caused the spreading of the infection in the hospital. As we noticed, nosocomial infection by S. typhimurium could occur during the whole year and had an increased incidence in winter. Due to pathogens isolated from those patients were highly resistant to antibiotics so the nosocomial infection could delay the hospitalization time, therefore how to control it became an important aspect of the hospital.

Levels of sexual hormones in relation with syndrome-differentiation of TCM in patients of chronic renal failure

Determinations of plasma levels of sexual hormones in 43 male patients of chronic renal failure showed that the content of testosterone (T) decreased markedly, while estradiol (E2) and E2/T ratio were obviously higher than in normal subjects, with no significant correlation between the levels of these sexual hormones and renal function. According to syndrome-differentiation of TCM, 17 of the 43 cases belonged to deficiency of Kidney-yang, and the other 26 cases deficiency of Kidney-yin. In the patients with deficiency of Kidney-yang, the E2 level was not increased, but the T content decreased to make the E2/T ratio apparently elevated; whereas in the patients with deficiency of Kidney-yin, both E2 and E2/T were elevated. The level of E2 in deficiency of Kidney-yin was markedly higher than that in deficiency of Kidney-yang. The results indicated that patients of chronic renal failure of the type of deficiency of Kidney-yang differed in syndrome as well as in levels of the sexual hormones from the type of deficiency of Kidney-yin; however, the sexual hormones were not correlated with the renal functions in the two types of patients.

[Electron microscopic observation on the killing of human lung carcinoma cells by lymphokine-activated killer cells (LAK cells) in vitro]

The interactions and reactions between co-cultured LAK cells and target cells were observed under scanning and transmission electron microscopy. Close contacts between these two cells were necessary to effect and sustain the killing process. In the contact area, there were prominent changes of the cell surface structures of both cells. The active motility of LAK cells accelerated the detachment and disintegration of the target cells. Lack of dense (killing) granules in the cytoplasm of LAK cells and the apoptotic death pattern of the affected target cells suggest that a non-perforin-dependent mechanism might be involved in killing. Morphologically, the killing process of LAK cells was basically similar to that of CTL and NK cells.

An analysis of the educational levels of migrants

"The educational level has significant bearings on the migration of population. As one of the factors that can brook no underestimation in the developing commodity economy, it determines, to a certain extent, the size, direction, and occupation or profession of population migration. The Institute of Population at the Academy of Social Sciences of China conducted a sampling survey of the migration of population in 74 cities of 16 provinces, municipalities and autonomous regions in 1986, and this paper presents a summary analysis of the dynamics of different educational levels of the migrating population surveyed."

E-rosette formation with SRBC and changes in cAMP level of hog lymphocytes--a study of certain affecting factors

A further study of cAMP change in porcine lymphocytes after E-rosette formation is presented in the present report using peripheral blood lymphocytes of pig mixed with different concentrations of SRBC membrane as well as SRBC treated with different enzymes for modification of the rosette formation. It has been found that cAMP enhancement in lymphocyte follows the increase in the concentration of SRBC membrane used, and that a similar relation appeared between modification of cAMP and enzyme-treated SRBC in the rosette formation. It has also been found that after rosetting with SRBC, cAMP level of lymphocytes began to rise within 1 min, reached its peak at 10 min and then returned to control level in about 8 hr.