Hypercapnic acidosis and dimethyl amiloride reduce reperfusion induced cell death in ischaemic ventricular myocardium

OBJECTIVE

The aim was to investigate the effects of slowing the recovery of ischaemia induced intracellular acidosis with hypercapnic acidosis or dimethyl amiloride (DMA) on the extent of reperfusion induced cell death.

METHODS

Isolated arterially perfused rabbit papillary muscles and septa were suspended in a controlled atmosphere and perfused with a modified Tyrode solution containing erythrocytes and trypan blue (500 microM). Ischaemia was produced by arrest of perfusion and withdrawal of atmospheric O2. Extracellular pH of the muscle during reperfusion was controlled by adjusting the pH of the perfusate (pH 6.6 or pH 7.6 with and without DMA 20 microM) and changing the PCO2 of the chamber atmosphere. After 30 min of reperfusion following 30 min (group A) or 60 min (group B) of ischaemia, papillary muscles were fixed with paraformaldehyde. Cell death was assessed by trypan blue staining of nuclei in histological sections of the papillary muscles.

RESULTS

The magnitude of cell death was greatest after reperfusion with pH 7.6 as measured by the percentage of nuclei staining with trypan blue (15.1% in group A; 41.8% in group B). By contrast, reperfusion at pH 6.6 reduced cell killing (group A, 3.6%; group B, 7.2%). Reperfusion at pH 7.6 with DMA (20 microM) also reduced trypan blue uptake (group A, 2.8%; group B, 3.8%). Despite the attenuation of cell death afforded by acidosis or Na+/H+ exchange inhibition, significant swelling of the extracellular space and microvascular injury was noted.

CONCLUSIONS

Hypercapnic acidosis and Na+/H+ exchange inhibition during reperfusion attenuate lethal reperfusion injury to ventricular myocardium and extend to the intact myocardium the concept of the "pH paradox" in which recovery of intracellular pH after reperfusion is a precipitating factor in lethal cell injury.

Immunolocalization of cellular fibronectins in the normal liver, cirrhosis, and hepatocellular carcinoma

Cellular (c) fibronectins (Fn) differ biochemically, immunologically, and functionally from plasma fibronectins (pFn). Most existing data on Fn distribution in the normal and diseased liver require revision because those studies were based on reagents that did not distinguish pFn from cFn and predated the development of specific cFn monoclonal antibodies (Mabs). We immunostained cryosections of normal adult livers (n = 5), cirrhotic livers (n = 20), and livers with hepatocellular carcinoma (HCC) (n = 10) by the avidin-biotin-complex method with specific Mabs to the extradomains A and B (EDA, EDB) and oncofetal (Onc) isoforms of cFn. Selected samples were stained with an antiserum to pFn; fetal livers served as controls. Normal and cirrhotic livers showed EDA-cFn staining in the portal, septal, and perisinusoidal matrix; its distribution was more restricted than that of pFn. In cirrhosis, EDA-cFn reactions were strongest at sites of piecemeal necrosis and around proliferating ductules in biliary cirrhosis. EDA-cFn reactions were consistently most intense in the matrix of HCC. Distinct from adult normal and cirrhotic livers, reactions for EDB- and Onc-cFn were noted exclusively in most cases of HCC. We conclude that the only cFn isoform indigenous to the normal adult liver matrix is EDA-cFn. Enhanced EDA-cFn in cirrhotic livers may serve as indicator of active stromal remodeling. The restriction of EDB- and Onc-cFn to a large subset of HCC and the putative role of cFn in modulating cell-matrix adhesive interactions would suggest that the emergence of these molecules may be related to the variably invasive and metastatic properties of these tumors.

Prognosis of patients > or = 70 years of age with non-Q-wave acute myocardial infarction compared with younger patients with similar infarcts and with patients > or = 70 years of age with Q-wave acute myocardial infarction

In this study, 70 patients > or = 70 years of age admitted to the coronary care unit with non-Q-wave acute myocardial infarction (AMI) were followed prospectively for 1 year, and the clinical course in these patients was compared with that in 61 patients < 70 years with non-Q-wave AMI and 56 patients > or = 70 years with Q-wave AMI. Compared with the younger patients with non-Q-wave AMI, older patients were more likely to develop atrial fibrillation (23% vs 8%; p < 0.05) and congestive heart failure (53% vs 30%; p < 0.01), and less likely to receive thrombolytic therapy (9% vs 28%; p < 0.01), cardiac catheterization (41% vs 72%; p < 0.01), and coronary angioplasty (20% vs 39%; p < 0.05). Hospital mortality did not differ significantly between older and younger non-Q-wave AMI patients (10% vs 3%), but 1-year mortality was higher in the elderly (36% vs 16%; p = 0.02). Elderly patients with Q-wave AMI had more in-hospital complications, including death (25% vs 10%; p < 0.05), than elderly patients with non-Q-wave AMI. In contrast, postdischarge mortality was higher in elderly patients with non-Q-wave AMI, so that total mortality at 1 year was similar in the 2 groups. Overall, elderly patients with non-Q-wave AMI accounted for 62% of all deaths occurring during the first year after discharge (relative risk 2.6 compared with other groups; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Rural development and rural to urban migration in China 1978-1990

"Economic reforms since the late 1970s have brought about significant changes in rural China. A large number of surplus rural labourers have been released from the agricultural sector and there has been a massive transition of rural residents from agricultural to non-agricultural employment. These changes will be analyzed by examining the changes in the employment structure of rural residents.... It is found that town and country populations tended to move to towns at the intra-provincial level, but to cities at the interprovincial level. Out-migrants from cities tended to move to cities at both the intra- and inter-provincial levels."

Cell dissociation with papain reduces the density of cGMP-activated channels of the retinal rod

A proteolytic enzyme, papain, is the enzyme commonly used for dissociation of retinal neurons. To ask whether papain modifies the activity of ion channels, cGMP-activated channels were recorded in inside-out membrane patches excised from the bullfrog rod outer segment, and the activity was compared between cells dissociated using papain and cells dissociated mechanically. While the affinity to cGMP, I-V relation, channel kinetics, and single-channel current amplitude were almost the same in both papain-treated and the control preparations, the total current flowing through the patch membrane of the papain-treated cells was reduced to about 20% of the control, suggesting that papain reduced the density of cGMP-activated channels.

In vitro synergism of concentrated Allium sativum extract and amphotericin B against Cryptococcus neoformans

Allium sativum (garlic) derived preparations are used alone or with amphotericin B in Asia to treat human systemic fungal infections and cryptococcal meningitis. To evaluate the scientific merit of using allicin-derived compounds as an anti-fungal drug, we prepared a concentrated A. sativum extract that contained 34% allicin, 44% total thiosulfinates, and 20% vinyldithiins. We found that the concentrated extract possessed potent in vitro fungistatic and fungicidal activity against 3 different isolates of Cryptococcus neoformans. The minimum inhibitory concentration of the concentrated garlic extract against 1 x 10(5) organisms of C. neoformans ranged from 6 to 12 micrograms/ml. In addition, in vitro synergistic fungistatic activity with amphotericin B was demonstrated against all isolates of C. neoformans. This study lends laboratory support for the treatment of cryptococcal infections with concentrated garlic extracts.

Patella and patellofemoral resurfacing (37 cases report)

Chondromalacia and patellofemoral osteoarthritis are common diseases that cause pain and disablement of the knee. Conservative therapy is not always effective. Since 1983 we have used isolated polyethylene patellar prosthesis for patella resurfacing of 19 patients with patellofemoral osteoarthritis. After an average of 44.9 months follow-up, we found the treatment was not as satisfactory as earlier trials. The main reason is the wide erosion of femoral condyle caused by the polyethylene patella. To overcome this shortness, we designed a new type of patellofemoral prosthesis which is named Y-L-Q. From January, 1991 to November, 1993, we used this prosthesis to treat 16 knees of 13 patients with patellofemoral osteoarthritis. Most of those patients improved both symptomatically and functionally. The good to excellent results rate was 87.5% (14/16 knees) at the time of an average 16 months follow-up. The early results of our experience with patellofemoral resurfacing are encouraging, and extended follow-ups are in progress.

Marked activation delay caused by ischemia initiated after regional K+ elevation in in situ pig hearts

BACKGROUND

Conduction mediated by the slow inward (Ca2+) current occurs in vitro under specific experimental conditions but has not been documented in ventricular muscle in vivo during regional myocardial ischemia, perhaps because certain constituents of ischemia (including hypoxia and acidosis) may inhibit the Ca2+ current in this setting. We hypothesized that slow conduction mediated by the Ca2+ current could occur during acute ischemia in situations in which the extracellular K+ rise was more marked relative to the degree of acidosis, as may occur at ischemic boundaries.

METHODS AND RESULTS

In open-chest, anesthetized swine, an arterial shunt from the carotid artery to the mid-left anterior descending coronary artery was created through which a solution of KCl was infused to raise extracellular K+ ([K+]e) to approximately 9.4 mmol/L before the initiation of ischemia, which we termed "K(+)-modified ischemia." Ischemia initiated at a normal [K+]e ("unmodified ischemia") resulted in a mean activation delay in the center of the ischemic zone of 55 +/- 26 milliseconds after 5 minutes of ischemia and a decrease in epicardial longitudinal conduction velocity from 53 to 21 cm/s before the onset of conduction block. K(+)-modified ischemia resulted in a mean activation delay in the center of the ischemic zone of 181 +/- 8 milliseconds and a decrease in epicardial longitudinal conduction to less than 10 cm/s. K(+)-modified ischemia was associated with ventricular fibrillation in 85% of episodes compared with 28% of episodes of unmodified ischemia (P < .01). Verapamil prevented the occurrence of marked activation delay during K(+)-modified ischemia, producing local activation block following a maximum activation delay of 74 +/- 25 milliseconds. In two experiments, responses mediated by the slow inward current were produced by regional K+ elevation to 15 to 16 mmol/L, followed by concomitant regional administration of epinephrine (10(-7) mol/L). Regional [K+]e elevation alone to this level resulted in local activation block following a maximum activity delay of 70 to 80 milliseconds, whereas administration of epinephrine in combination with high [K+]e resulted in return of local activation with an activation delay of 160 to 180 milliseconds (ie, similar to that during K(+)-modified ischemia).

CONCLUSIONS

Compared with unmodified ischemia, K(+)-modified ischemia resulted in marked activation delay and a high incidence of ventricular fibrillation. Based on measurements of longitudinal conduction velocity, the inhibitory effect of verapamil, and the results of experiments with high [K+]e plus epinephrine, we conclude that the marked activation delay during K(+)-modified ischemia represents conduction mediated by the slow inward current. Because the conditions produced by K(+)-modified ischemia (high [K+]e with minimal acidosis) are similar to conditions in and near ischemic border regions, we hypothesize that responses mediated by the slow inward current may occur in such regions during unmodified ischemia and may participate in the development of reentrant arrhythmias.

Influence of iron deficiency on serum IgG subclass and pneumococcal polysaccharides specific IgG subclass antibodies

The serum IgG subclass concentrations in 47 cases and specific IgG subclass antibodies against pneumococcal polysaccharides (PnPs) were measured in 18 cases with iron deficiency. IgG subclass deficiencies were found in 28 (59.6%) cases with the frequency in order as IgG4 (27.7%, 13/47), IgG1 (21.3%, 10/47), IgG3 (14.9%, 7/47), and IgG2 (2.1%, 1/47). Compared with age-matched healthy children, the mean concentration of serum IgG4 and IgG1, and PnPs specific IgG1, IgG2 antibodies were decreased in children with iron deficiency. Decreased CD4+ cells and CD4+/CD8+ ratio in peripheral blood, low interleukin-6 (IL-6) activity, reduced lymphocyte proliferative responsiveness and increased recurrent respiratory tract infections (RRTI) were found in iron deficiency children. These results suggested that serum IgG subclass and PnPs specific IgG subclass antibody deficiencies caused by dysfunction of the regulation of T lymphocyte on B lymphocyte may be related to the susceptibility to RRTI in children with iron deficiency.

cis-regulatory sequences responsible for alternative splicing of the Drosophila dopa decarboxylase gene

The Drosophila dopa decarboxylase gene, Ddc, is expressed in the hypoderm and in specific sets of cells in the central nervous system (CNS). The unique Ddc primary transcript is alternatively spliced in these two tissues. The Ddc CNS mRNA contains all four exons (A through D), whereas the hypodermal mRNA contains only three exons (A, C, and D). To localize cis-regulatory sequences responsible for Ddc alternative splicing, a Ddc minigene and several fusion genes containing various amounts of Ddc sequences fused to fushi tarazu (ftz) exon 1 were constructed and introduced into flies by P-element-mediated germ line transformation. We find that Ddc intron ab and exon B are sufficient to regulate Ddc alternative splicing, since transcripts of a minimal fusion gene containing most of Ddc intron ab and exon B are spliced to exon B in the CNS but not in the hypoderm. These results indicate that Ddc alternative splicing is regulated by either a negative mechanism preventing splicing to exon B in the hypoderm or a positive mechanism activating splicing to exon B in the CNS. Our previous data suggest that Ddc hypodermal splicing is the actively regulated splicing pathway (J. Shen, C. J. Beall, and J. Hirsh, Mol. Cell. Biol. 13:4549-4555, 1993). Here we show that deletion of Ddc intron ab sequences selectively disrupts hypodermal splicing specificity. These results support a model in which Ddc alternative splicing is negatively regulated by a blockage mechanism preventing splicing to exon B in the hypoderm.

[Modified en bloc resection procedure for malignant tumor of the shoulder girdle]

En bloc resection of the shoulder girdle (Tikhoff-Linberg procedure) is a valuable limb-sparing surgical technique for bony and soft tissue malignant tumor in and around the proximal humerus and shoulder girdle. Significant amount of hand-elbow function is maintained with the procedure, and long time results in the treatment of neoplasms by this technique was found to be the same as by the method of a forequarter amputation or the shoulder disarticulation in the English literature. Four cases with malignant tumor in the shoulder girdle was treated with this modified method in our department. The average follow-up was 8 years. One case died due to another kind of tumor 6 years after operation, and other 3 cases are alive and disease free.

Application of internal fixation in the treatment for tuberculosis of the spine

This is a study of 18 patients who had surgical treatment for spinal tuberculosis. All patients were admitted with the spinal tuberculosis and treated with a combination of anterior debridement and bone graft with posterior internal fixation using the Luque or Dick technique. The patients were able to walk within a few days postoperation. Three to seven years follow-ups show no recurrence, kyphosis and/or solid fusion.

[Long-term follow-up of patients with patella resurfacing]

Patellar resurfacing was performed by the authors. From 1983 to 1988, 19 cases (22 knees) with patello-femoral osteoarthritis were treated with this procedure in our hospital. Excellent and good results were recorded in 13 cases (59.1%) one year after operation, but were zero in the long-term follow-up (average 8.7 years) because of recurrent knee pain due to the wearing of the cortex of the femoral groove. Further operation was necessary for those cases, such as patellectomy or total knee replacement. Since 1991 Y-L-Q's type of patellofemoral replacement has been used in 11 cases in our department to alter the isolated resurfacing of the patella. The femoral groove was replaced with a metallic implant that allows sliding of a polyethylene patella to prevent the wearing of the femoral cortex. Preliminary results are good.

[Etiologic study on the relationship between HBV, HCV and HCC]

A total of 110 HCC patients were sampled randomly in 20 townships of Qidong county (a higher incidence area of HCC in China) from Mar. to Sept. 1989. Each patient was paired with two healthy persons as control. The results showed that the prevalences of HBV and HCV in 110 patients were 85.45% and 17.27% respectively, and were significantly higher that in control (50.45% and 4.09%). Using Conditional Logistic Regression Model. we found that the main risk factors of HCC in Qidong were HBsAg and Pre-S2 for HBV and anti-HCV for HCV. The OR value were 10.22, 2.96 and 2.63, respectively. Drinking tea was the only protective factor (OR = 0.36). Among 110 HCC patients. 13.64% were positive for both HBV and HCV. The OR value was the highest (6.48). 88.18% patients were either HBV or HCV positive. The OR values were similar (3.90 and 3.89). It suggests that the most important risk factor of HCC in Qidong was HBV infection because it had a higher prevalence among the population while the HCV infection having an equal OR value was also a risk factor.

Persistent increase of hippocampal presynaptic axon excitability after repetitive electrical stimulation: dependence on N-methyl-D-aspartate receptor activity, nitric-oxide synthase, and temperature

The electrical excitability of Schaffer collateral axons and/or terminals was studied in hippocampal slices by monitoring single, CA3 pyramidal neurons activated antidromically from CA1 stratum radiatum. At 22 degrees C, weak, repetitive stimulation with as few as 10 impulses at 2 Hz led to a robust lowering of the antidromic activation threshold that lasted > 30 min. The effect was completely absent at 32 degrees C and was blocked by both the N-methyl-D-aspartate receptor antagonist, 2-amino-5-phosphonovalerate and the inhibitor of nitric-oxide synthase, L-nitro-arginine methyl ester. Such threshold lowering would alter the variance of synaptic responses from axons stimulated in the variable excitation region of their input-output functions. These results thus raise important doubts about the interpretation of experiments in which the so-called minimal-stimulation method has been used at reduced temperature to infer changes in quantal transmission during hippocampal long-term potentiation. In the present experiments, no changes were observed in the estimate of excitatory postsynaptic potential quantal content in long-term potentiation experiments at either temperature, which could not be accounted for by an artificial, temperature-dependent change in the responsiveness of presynaptic axons.

The fern Polypodium decumanum, used in the treatment of psoriasis, and its fatty acid constituents as inhibitors of leukotriene B4 formation

The fern Polypodium decumanum, commonly called Calaguala, has a clinically documented use in South America and Spain in the treatment of psoriasis. One of the inflammatory mediators isolated in abnormally high quantities in the psoriatic skin is leukotriene B4 (LTB4). Calaguala was tested in an in vitro model using human leukocytes for its ability to inhibit the LTB4 formation. The inhibition was found to be caused by the polyunsaturated fatty acids (PUFAs) linoleic, linolenic and arachidonic acid. IC50 values were determined for the isolated acids and compared to a group of closely related acids also commonly found in nature. The IC50 values for most acids tested were of the same magnitude (20-60 microM) except for arachidonic acid which showed stimulatory activity and 8(R) hydroxylinoleic acid which gave 30% inhibition with the highest dose tested (120 microM). The amounts of PUFAs in different Calaguala extracts were quantitatively analysed and it is concluded that the fatty acid constituents of Calaguala may contribute to the clinical effects of the extract.

Ultraviolet solid-state laser (213-nm) photorefractive keratectomy. In vivo study

BACKGROUND

The pulsed ultraviolet 213-nm solid-state laser has been demonstrated as an alternative to the gas argon-fluoride 193-nm excimer laser for photorefractive keratectomy (PRK). The authors studied the clinical course and histopathologic changes occurring in rabbit corneas after PRK with a 213-nm solid-state laser.

METHODS

The 213-nm output of neodymium:YAG frequency-quintupled laser was used to create 5-mm optical zone ablations in seven pigmented rabbit corneas. The radiant exposure was 250 mJ/cm2 delivered through a computer-controlled scanning delivery system with a spot size of 0.5 mm. The target ablation was 4.0 diopters with an estimated ablation depth of 40 microns. A clinical estimate of corneal epithelial healing and stromal haze was made at intervals over the 3-month study period. Animals were killed immediately after ablation, or at 10 days, 1 month, or 3 months after ablation. Corneal tissue was preserved for light microscopy and transmission electron microscopy at each study interval.

RESULTS

All corneas re-epithelialized within 10 days postoperatively. Anterior stromal haze was clinically visible at 3 days, increased until approximately 1 month, and then gradually decreased over the succeeding 2 months. Residual subepithelial haze was visible at 3 months. Results of histopathologic study documented normal epithelium healing over time; the basement membrane retained its regular thickness and hemidesmosomes were abundant at 3 months. The anterior stroma had an increased number of fibroblasts at 10 days, many of which remained until 1 month. A mild, transient, cellular reaction occurred throughout the thickness of the stroma and the endothelium.

CONCLUSION

Using the 213-nm ultraviolet solid-state laser with a scanning delivery system, PRK shows a similar clinical course and histopathologic findings to the 193-nm excimer PRK study in rabbits. It is a clinically viable procedure for refractive surgery and requires further human clinical trails to determine its efficacy.

Laser-induced photoacoustic signal phase study of stratum corneum and epidermis

Laser-induced photoacoustic signal phase was employed for measurements of optothermal parameters of pig abdomen stratum corneum and epidermis. The non-radiative relaxation time was found to be 28 ms and the thermal diffusion time was 370 ms, yielding a thermal diffusivity value of (4.1 +/- 0.8) x 10(-4) cm2 s-1. This value compares well with other literature values for skin obtained using photothermal techniques.

Clinical significance of elevated serum soluble interleukin-2 receptor in gastric cancer

This is China's pilot study in the assessment of the diagnostic value of serum soluble IL-2 receptor (sIL-2R) in gastric cancer. We measured its level by ELISA method in 45 patients with gastric cancer (without metastasis: 32; with metastasis: 5; recurrence: 8) 27 gastric ulcer, 27 superficial gastritis and 44 healthy controls. The mean-serum sIL-2R levels were significantly elevated in cancer patients, those with metastasis showed even higher levels than those without metastasis. These results suggested that sIL-2R can be used as a marker of host biological response in gastric cancer patients as well as a tumor marker for the diagnosis of the disease.

Fluid flow modulates vascular endothelial cytosolic calcium responses to adenine nucleotides

OBJECTIVE

To determine whether fluid flow influences the action of soluble vasoactive agonists on vascular endothelium.

METHODS

Confluent monolayers of bovine aortic endothelial cells (BAEC) were cultured on glass coverslips, prelabeled with the Ca(2+)-sensitive dye fura-2, and placed in a parallel-plate flow chamber designed to generate defined laminar fluid flow. Cytosolic free Ca2+ concentration ([Ca2+]i) in individual BAEC was monitored during perfusion with medium containing adenine nucleotide under defined flow conditions.

RESULTS

Continuous perfusion with ATP (0.3-3.0 microM) or ADP (0.1-1.0 microM) evoked repetitive oscillations in [Ca2+]i in individual BAEC. The frequency of the [Ca2+]i oscillations was dependent on both nucleotide concentration and levels of applied shear stress; at constant bulk concentration of nucleotide, the frequency increased with shear stress. Stopping flow in the continuous presence of agonists immediately extinguished the oscillatory response. Elimination of extracellular Ca2+ did not inhibit the [Ca2+]i oscillations. In the presence of nonhydrolyzable nucleotide analog, ATP gamma S or ADP beta S, application of flow resulted in similar shear-dependent [Ca2+]i oscillations, suggesting that flow modulation of the [Ca2+]i response was not simply due to depletion of ATP or ADP in the vicinity of BAEC monolayers as a result of hydrolysis of nucleotides by ectonucleotidases.

CONCLUSIONS

These findings suggest that local hemodynamic conditions may modulate the action of vasoactive agents on the vascular endothelium in vivo.

Spatial-dynamic population systems: analysis and projection

"In this paper a set of more-detailed multiregional population accounts is proposed to specify more realistically the exposure time of populations at risk for various components of population change. The concepts of population-time at risk and forward demographic rates based on the initial population are discussed. The relations of the forward demographic rates defined in this paper with the occurrence-exposure demographic rates are discussed. A more precise and straightforward multiregional population model is developed on the basis of forward demographic rates. The model is also expressed in the familiar matrix form of multiregional, cohort-survival models." Some applications of the model are made to data for China.

Na(+)-dependent high affinity uptake of L-glutamate in primary cultures of human fibroblasts isolated from three different types of tissue

Cultured human fibroblasts isolated from embryonic muscle, skin and peripheral nerve tissues were found to accumulate [3H]L-glutamate by a Na(+)-dependent uptake process strongly inhibited by several glutamate/aspartate analogues including D- and L-aspartate, D- and L-threo-3-hydroxyaspartate and L-trans-pyrrolidine-2,4-dicarboxylate but not D-glutamate. It was also reduced by elevated concentrations of K+, Rb+ and Cs+. The values of Km's were 5-20 microM, well within the 'high affinity' region. Variations in the capacity (Vmax) of [3H]L-glutamate uptake did not correlate with the origin (muscle, skin or nerve tissue) of the fibroblasts. The uptake characteristics suggest that it is mediated by a transport system similar to that commonly observed only in brain tissue.

Locus-specific variation in phosphorylation state of RNA polymerase II in vivo: correlations with gene activity and transcript processing

To investigate functional differences between RNA polymerases IIA and IIO (Pol IIA and Pol IIO), with hypo- and hyperphosphorylated carboxy-terminal repeat domains (CTDs), respectively, we have visualized the in vivo distributions of the differentially phosphorylated forms of Pol II on Drosophila polytene chromosomes. Using phosphorylation state-sensitive antibodies and immunofluorescence microscopy with digital imaging, we find Pol IIA and Pol IIO arrayed in markedly different, locus- and condition-specific patterns. Major ecdysone-induced puffs, for example, stain exclusively for Pol IIO, indicating that hyperphosphorylated Pol II is the transcriptionally active form of the enzyme on these genes. In striking contrast, induced heat shock puffs stain strongly for both Pol IIA and Pol IIO, suggesting that heat shock genes are transcribed by a mixture of hypo- and hyperphosphorylated forms of Pol II. At the insertion sites of a transposon carrying a hybrid hsp70-lacZ transgene, we observe only Pol IIA before heat shock induction, consistent with the idea that Pol II arrested on the hsp70 gene is form IIA. After a 90-sec heat shock, we detect heat shock factor (HSF) at the transposon insertion sites; and after a 5-min shock its spatial distribution on the induced transgene puffs is clearly resolved from that of Pol II. Finally, using antibodies to hnRNP proteins and splicing components, we have discerned an apparent overall correlation between the presence and processing of nascent transcripts and the presence of Pol IIO.

Identification of a cryptic gene associated with an insertion sequence not previously identified in Bacillus thuringiensis

After screening several Bt strains with a cryII toxin probe, clones from two strains were found to contain a cryptic cryIIB gene associated with an insertion sequence element belonging to the IS2/IS3 family. The lack of expression of this gene appears to result from mutation of the upstream orf2 gene which has been shown to be necessary for cryII expression.

Biophysical tools for structure-based drug design

The emerging understanding of the structural basis of biological function has made possible a new technology of rational drug design. This technology uses a combination of modeling and intensive computational tools, but also relies critically on direct structural methods for verification and to provide direction for new leads. The present work illustrates applications of this technology to ligand design for several model systems, including iterative modeling and crystallographic design of streptavidin ligands, ranking of streptavidin ligands using comparative molecular field analysis and ranking of thermolysin inhibitors using Poisson-Boltzman methods.

Immunologic abnormalities in children with acute Kawasaki disease

Spontaneous release of IgG, production of IgG, IgM and IgG subclasses induced by PWM in vitro, serum IgG, IgM, IgA and IgG subclasses were measured in 23 patients with acute Kawasaki disease (KD). The results showed that there was polyclonal B cell activation with significantly increased IgG1 and IgG3. As compared with 21 healthy controls, the mean activities of B cell growth factors (BCGFs), B cell differentiation factors (BCDFs) and interleukin 6 (IL-6) were significantly elevated. IL-6 activity was correlated with the production of IgG, IgG1, IgG3 and IgM, while BCGFs and BCDFs were also correlated with IgG1. The serum level of circulating tumor necrosis factor (TNF) determined in 16 patients with acute KD using double antibody ELISA was 1.86-8.83 micrograms/ml, but it was less than 1 microgram/L in normal controls. The clinical value of increased TNF in serum is discussed.

Tissue-specific alternative splicing of the Drosophila dopa decarboxylase gene is affected by heat shock

The Drosophila dopa decarboxylase gene, Ddc, is expressed in the hypoderm and in a small number of cells in the central nervous system (CNS). The unique Ddc primary transcript is alternatively spliced in these two tissues. We investigated whether Ddc splicing in the CNS is a general property of the CNS or a unique property of the cells that normally express Ddc by expressing the Ddc primary transcript ubiquitously under the control of an Hsp70 heat shock promoter. Under basal expression conditions, Ddc splicing shows normal tissue specificity, indicating that the regulation of Ddc splicing in the CNS is tissue specific rather than cell specific. Previous studies have shown that severe heat shock blocks mRNA splicing in cultured Drosophila melanogaster cells. Our results show that splicing of the heat shock-inducible Hsp83 transcript is very resistant to heat shock. In contrast, under either mild or severe heat shock, the splicing specificity of the heat shock-induced Ddc primary transcript is affected, leading to the accumulation of inappropriately high levels of the CNS splice form in non-CNS tissues. The chromosomal Ddc transcript is similarly affected. These results show unexpected heterogeneity in the splicing of individual mRNAs as a response to heat shock and suggest that the Ddc CNS-specific splicing pathway is the default.

A clinical trial of a slow-release formulation of acetylsalicylic acid in patients at risk for preeclampsia

The formation of thromboxane A2 (TXA2) in maternal and foetal cord serum was measured at birth in eight control patients and in 13 patients taking 100 mg of a slow-release formulation of acetylsalicylic acid. The serum concentrations of TXB2 (a stable end product of TXA2 hydrolysis) in both maternal and cord serum from patients who ingested the acetylsalicylic acid formulation were significantly lower (P < 0.01) than those in control subjects. Acetylsalicylic acid was not detected (< 30 ng ml-1) in maternal plasma from six mothers and in cord plasma from seven foetuses in the acetylsalicylic acid-treated group. The mean cord to maternal plasma concentration ratios for detectable acetylsalicylic acid and salicylate were 0.62 +/- 0.19 (s.d.) (n = 6) and 0.84 +/- 0.16 (n = 13), respectively. We conclude that low doses of acetylsalicylic acid given in a slow-release form to mothers during pregnancy cause depression of TXA2 formation in the foetal blood.

Clinical and experimental studies on shallow needling technique for treating childhood diarrhea

Treatment of diarrhea in children by shallow needling and by drugs was studied in 3 separate groups for comparison. For Group I, the lateral line II of the forehead was taken, i.e. the upper, middle and lower points of the line staring from Toulinqi (UB 15) vertically downwards to the place 1 cm below the hairline were selected. For Group II, shallow needling was done on body acupoints, the main points selected being Qihai (Ren 6), Shuifen (Ren 9), bilateral Tianshu (St 25), and bilateral Zusanli (St 36); the adjuvant acupoints were Taibai (Sp 3) and Gongsun (Sp 4). The depth of shallow needling was merely puncturing the skin. For Group III the drugs used were Liteling, Berberine, Gentamycin, Ampicillin, and SMZ Co. The results of treatment in Group I and II differed insignificantly, while both were significantly superior to drugs in Group III. Experimental studies also showed that shallow needling enhanced the humoral and cellular immunity and promoted the intestinal peristaltic function.

Regulation of adenine nucleotide concentration at endothelium-fluid interface by viscous shear flow

The action of adenine nucleotides on vascular endothelial cells is apparently mediated by the local flow conditions. Because nucleotides are sequentially degraded from ATP-->ADP-->AMP-->adenosine by ecto-enzymes at the endothelial surface, it has been hypothesized that the observed flow effect is caused by the flow-dependent change of nucleotide concentration at the cell surface. In this study, we have calculated the concentration profiles of adenine nucleotides at the cell surface under flow conditions encountered in an in vitro parallel-plate flow system, as has been used in several related experimental studies. When medium containing uniformly distributed ATP is perfused over endothelial monolayers, our results show that ATP concentration in the cell vicinity gradually decreases in the streamwise direction as a result of enzymatic degradation. This hydrolysis of ATP results in the generation of ADP, and ADP concentration in turn gradually increases at the cell surface. The concentration profiles of nucleotides are dependent on the levels of applied wall shear rate. As the corresponding shear stress increases from 0.1 to 30 dynes/cm2, ATP concentration at the cell surface at the center of coverslip increases from 0.66 to 0.93. Under no-flow conditions, our model predicts a steady decline of ATP concentration and a transient increase of ATP-derived ADP, comparable to the published results of previous experiments. These numerical results, combined with our recent experimental data, provide insights into the cellular mechanisms by which hemodynamic flow modulates the effects of vasoactive agents on endothelium.

Analysis of urban-rural population dynamics of China: a multiregional life table approach

This is the second of two papers in which the urban-rural population dynamics of China is analyzed. Urban-rural population life tables are constructed in this paper. The differential urban and rural population dynamics are revealed by the calculations of life expectations, net reproduction expectations, and net migraproduction expectations in the urban and rural regions of China.

Hemodynamic effects and the effective treatment of naloxone on experimental acute pancreatitis in dogs

Dog model of acute pancreatitis, induced by intrapancreatoductal injection of fresh trypsin-bile mixture, was used to investigate the effects of naloxone on hemodynamic changes in acute pancreatitis. In the control group, acute pancreatitis was induced and characterized hemodynamically by the decrease in maximum positive and negative dP/dt (+/- dP/dtmax), cardiac output (CO) and cardiac index (CI), and increase in pulmonary vascular resistance (PVR) and systemic vascular resistance (SVP), as well as early reduction of pancreatic blood flow (PBF). In the naloxone treated group, naloxone was given intravenously 10 minutes after the induction of acute pancreatitis (80 micrograms/kg as a bolus + 80 micrograms/kg/h for 3 hours). It was found that naloxone significantly increased PBF and the +/- dP/dtmax effectively prevented the significant decrease in CO, CI and increase in PVR, SVR observed in untreated acute pancreatitis; and significantly reduced the severity of pancreatitis, as assessed by both histological staging and mortality rate. These results suggest that naloxone appears to limit the progression from edematous to hemorrhagic pancreatitis through preserving PBF and improving systemic hemodynamics at the early phase of acute pancreatitis; hence the hypothesis that endogenous opioid peptides may play a role in the pathophysiology of acute pancreatitis.

Effect of naloxone on the haemodynamics and the outcome of experimental acute pancreatitis in dogs

Endogenous opioid peptides may play a role in the genesis of pancreatic damage in acute pancreatitis. The effects of naloxone on the haemodynamic changes in acute pancreatitis were investigated by inducing it in dogs with pancreatic ductal injection of fresh trypsin-bile mixture. In the control group (n = 8), acute pancreatitis was characterized haemodynamically by falls in the maximum positive and negative dP/dt (+/- dP/dt), cardiac output (CO) and cardiac index (CI), and increases in the pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR) as well as an early reduction of pancreatic blood flow (PBF). In another set of eight dogs (naloxone group), naloxone was given intravenously 10 min after the induction of acute pancreatitis (80 micrograms/kg as a bolus + 80 micrograms/kg/h for 3 h). Compared with untreated dogs, naloxone significantly increased PBF and the +/- dP/dtmax; prevented the significant decreases in CO and CI and increases in PVR and SVR, and reduced significantly the severity of pancreatitis, as assessed by both the histological staging and the mortality rate. These results suggest that naloxone limits the progression of acute pancreatitis from oedematous to haemorrhagic form. It is proposed that endogenous opioid peptides may play a role in the pathophysiology of acute pancreatitis.

Fluid shear stress modulates cytosolic free calcium in vascular endothelial cells

Cytosolic free Ca2+ concentration ([Ca2+]i) was monitored in single and groups of fura-2-loaded bovine aortic endothelial cells (BAEC) during exposure to laminar fluid shear stress. Application of a step increase in shear stress from 0.08 to 8 dyn/cm2 to confluent BAEC monolayers resulted in a transient increase in [Ca2+]i, which attained a peak value in 15-40 s, followed by a decline to baseline within 40-80 s. The magnitude of the [Ca2+]i responses increased with applied shear stress over the range of 0.2-4 dyn/cm2 and reached a maximum at greater than 4 dyn/cm2. Transient oscillations in [Ca2+]i with gradually diminishing amplitude were observed in individual cells subjected to continuous high shear stress. Elimination of extracellular Ca2+ with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, blockade of Ca2+ entry with lanthanum, depolarization of the cell membrane with high K+, and preconditioning of BAEC in steady laminar flow had little effect on the [Ca2+]i response. In the presence of ATP or ADP, application of shear stress caused repetitive oscillations in [Ca2+]i in single BAEC, whose frequency was dependent on both agonist concentration and the magnitude of applied shear stress. However, apyrase, an ATPase and ADPase, did not inhibit the shear-induced [Ca2+]i responses in standard medium (no added ATP or ADP), suggesting that the shear-induced [Ca2+]i response is not due to ATP released by endothelial cells.

Epidermal growth factor-induced survival and proliferation of neuronal precursor cells from embryonic rat mesencephalon

Neuronal and glial precursor cells were isolated from primary cultures of embryonic rat mesencephalon. The separation of precursor cells from the neurons was accomplished by the resuspension of the primary cells by trypsinization, followed by replating. This procedure resulted in the death of differentiated neurons and the survival of precursor cells. The survival and proliferation of the replated precursor cells required the presence of epidermal growth factor (EGF) in the culture medium. The precursor cells differentiated into neurons and astrocytes, as determined by immunocytochemical staining with antibodies to neuron specific enolase (NSE) and tau protein or glial fibrillary acidic protein (GFAP) respectively.

Is age an independent predictor of early and late mortality in patients with acute myocardial infarction?

PURPOSE

To determine whether advancing age is an independent predictor of increased mortality following acute myocardial infarction or simply a marker for more extensive cardiac disease, a higher prevalence of comorbid conditions, and/or differences in therapeutic approach.

PATIENTS

A total of 261 consecutive patients with documented acute myocardial infarction admitted to a university teaching hospital during a 1-year interval.

METHODS

Seventy-four variables were analyzed to determine univariate predictors of inhospital and 1-year post-discharge mortality. Multiple linear regression models were constructed to determine independent predictors of early and late mortality after adjusting for baseline and therapeutic differences between younger and older patients.

RESULTS

Compared with patients less than 70 years (n = 124), patients greater than or equal to 70 years (n = 137) were more likely (all p less than 0.05) to be female and have a prior history of ischemic heart disease. New York Heart Association functional class and Killip class on admission were higher in older patients, as were the admission serum creatinine and blood urea nitrogen levels. Serum albumin and peak creatine kinase levels were lower in older patients, but older patients were more likely to exhibit left ventricular hypertrophy or atrioventricular block on the initial electrocardiogram. Finally, younger patients were three times as likely to receive a thrombolytic agent and 66% more likely to receive intravenous beta-blockade than older patients, and younger patients were also more likely to receive heparin and intravenous nitroglycerin. Hospital mortality was 5.6% in patients less than 70 years versus 16.1% in patients greater than or equal to 70 years (p = 0.013). After adjusting for baseline and therapeutic differences, independent predictors of hospital mortality were systolic blood pressure on admission (inverse correlation, p = 0.0095), beta-blocker therapy (inverse correlation, p = 0.01), age (p = 0.014), peak creatine kinase level (p = 0.015), and Killip class (p = 0.035). Among hospital survivors, 1-year post discharge mortality was 6.8% in patients less than 70 years versus 19.1% in those greater than or equal to 70 years (p = 0.001). Independent predictors of post-discharge mortality after adjusting for age-related baseline and therapeutic differences were admission heart rate (p = 0.0004), age (p = 0.011), left ventricular ejection fraction (inverse correlation, p = 0.012), initial non-Q-wave myocardial infarction (p = 0.026), and the blood urea nitrogen level (p = 0.036).

CONCLUSION

After adjusting for multiple baseline and therapeutic differences between older and younger patients, age per se remains a strong independent predictor of both inhospital and 1-year post-discharge mortality rates in patients with acute myocardial infarction.

Analysis of urban-rural population dynamics for China

The multiregional demography approach is used in an analysis of the urban—rural population dynamics of China. Multiregional population-accounts and methods of estimation of demographic rates are developed on the basis of the multiregional population-accounts concept. An accounts-based urban—rural population projection model is established and used to project the population of China from 1988 to 2087.

Model representation of salicylate pharmacokinetics using unbound plasma salicylate concentrations and metabolite urinary excretion rates following a single oral dose

The pharmacokinetics of salicylic acid (SA) and its metabolites have been studied in 5 volunteers after administration of 3 g salicylic acid (as sodium salicylate) and collection of serial samples of blood and urine. SA and its metabolites were assayed with a HPLC method specific for each species. The urinary excretion rates of individual metabolites were analyzed using unbound plasma SA concentrations and Lineweaver-Burke plots. The analysis confirmed that the formation of SA urate (SU) and SA phenolic glucuronide (SPG) metabolites are saturable processes, and showed that the Michaelis-Menten values derived are consistent with earlier estimates derived solely from urinary data. The unbound salicylate plasma concentration-time profiles were then analyzed with various models assuming either saturable clearances for metabolite formation and/or saturable protein binding. The data were best described with a model that included both saturable protein binding and saturable metabolism. The model assumed first-order absorption kinetics and instantaneous distribution into extravascular and tissue compartments. The model was validated by comparing predicted relationships between the apparent volume of distribution, clearance, and plasma salicylate concentrations with previous relationships obtained using steady state data.