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.

[Effects of verapamil on prostacyclin, thromboxane and pancreatic blood flow of rats with experimental acute pancreatitis]

We studied the effects of the calcium channel blocker, verapamil on experimental acute pancreatitis (AP) in rats. The pancreatic blood flow (PBF) and pancreatic tissue perfusion (PTP) were measured after induction of AP. At the same time, the plasma levels of TXB2 and 6-keto-PGF1 alpha were determined by radioimmunoassay. The survival rate and the mean survival time after induction of AP were determined and the pancreatic histology was examined by light and electron microscopy. The results demonstrated a significant early fall in PBF and PTP, a marked increase in TXB2 levels and a slight increase in 6-keto-PGF1 alpha after induction of AP. Treatment with 0.1 mg/100 g verapamil significantly increased PBF and PTP, and decreased TXB2, resulting in a normalization of TXB2/6-keto-PGF1 alpha ratio. The treated animals also exhibited significant increase in the survival rate and the survival time. They also showed decrease in the severity of pancreatic hemorrhage and necrosis, and in the damage to the cellular ultrastructures. These data suggest that calcium blockade increases PBF and PTP, limits the prostanoid imbalance in the early phase of AP, and may influence the development of experimental acute pancreatitis in rats.

[Clinical value of the Chengdu classification of non-Hodgkin's lymphomas]

Two hundred forty-nine cases of non-Hodgkin's lymphomas (NHL) were reviewed by using the working classification of NHL (Chengdu, 1985). The results showed that the patients of 249 cases of NHL ranging in age from 5 to 76 years, with the mean age of 42 of the types were separated into three major prognostic groupings as follows: 1. low (41 of 249 cases, small lymphocytic 27 cases, lymphoplasmacytoid 2 cases, follicular cleaved 7 cases, follicular cleaved and noncleaved 5 cases); 2. intermediate (58 of 249 cases, diffuse cleaved 28 cases, diffuse cleaved and noncleaved 27 cases, follicular noncleaved 3 cases); and 3. high grade malignancy (150 of 249 cases, diffuse noncleaved 49 cases, lymphoblastic 41 cases, immunoblastic 13 cases, polymorphic 39 cases, clear cell 2 cases, histiocytic 6 cases). Each group was significantly different from the others (P less than 0.05). The prognosis of patients with angioimmunoblastic lymphadenopathy like T-cell lymphoma (9 of 249 cases) was not more significant (P greater than 0.05) than that of patients with other polymorphic lymphoma (30 of 249 cases). The results showed this Chengdu classification of NHL is good for practice and usage in clinical evaluation and routine surgical pathology.

Photoacoustic study of iron-deficiency anaemia

A photoacoustic spectrum of a smear of whole blood clearly shows all of the details of the haem absorption in an optical spectrum and good optical absorption data without a data extraction procedure. There are three peaks; gamma (420 nm), beta (550 nm), and alpha (585 nm) in the band 350-700 nm. For iron-deficiency anaemia the peak/peak ratios, ratios of the value of peak gamma to that of the peak beta and peak alpha, and the integral/integral ratios, ratios of the value of the integral under the peak gamma to that under the peak beta, peak alpha, peak beta and peak alpha are closely related to the variation of haemoglobin concentration. Linear relationships among the ratios and the Hb concentration are found. These ratios could be a good index of haem synthesis disturbance.

[An application of His bundle electrogram to locate fossa ovalis during percutaneous transseptal balloon valvuloplasty]

A new technique to locate the point of atrial septal puncture, i.e. His bundle electrogram locating method (HBELM), was reported. By using this HBELM, the successful rate of atrial septal puncture was 100% in 21 cases of mitral stenosis during percutaneous transseptal balloon valvuloplasty and in 5 cases of them, the puncture needle got into left atrium smoothly through patent fossa ovalis at the position determined by HBELM without making puncture. As well known, the point of atrial septal puncture is fossa ovalis. According to the anatomy, His bundle is located at the same horizontal line as fossa ovalis. After HBE being recorded, a horizontal line is drawn from the point of His bundle catheter electrode. The authors suggest that the intersect of this line with right border of thoracic vertebra should be the point of atrial septal puncture. The above study showed that HBELM for atrial septal puncture is a correct and easy method and may be better than other methods used before.

[Colo-rectal cancer in the elderly]

From September 1981 to December 1988, fiberoptic colonoscopy was performed in 4595 subjects, among whom 476 colorectal cancers were found. Among 692 subjects with ages beyond sixty, 164 (23.7%) colo-rectal cancers were discovered. This study shows that the median age of colo-rectal cancer has increased by 7 years from 45 of the 1950s to the 1970s. The incidence of cancer of the ascending colon is higher (8.5%) in subjects older than 60. It should be noted that 124 out of 164 (75.6%) patients had been misdiagnosed. With prolonging life expectancy in the Chinese population, we strongly advise fibercolonoscopy for the early detection of colo-rectal cancer in the elderly.

Immunoglobulin G subclass deficiency in children with recurrent respiratory tract infections

With monoclonal antibodies serum immunoglobulin G(IgG) subclasses were measured in seventy children aged 2 to 13 years with recurrent respiratory tract infections including upper respiratory tract infections, otitis media, sinusitis, asthmatic bronchitis and pneumonia. 211 healthy, aged-matched children served as control. IgG subclass deficiency was found in 19 out of the 70 patients (27.1%, single IgG1 deficiency in 7, IgG2 deficiency in 4, combined IgG1-IgG3 deficiency in 5, IgG1-IgG2-IgG3-IgG4 deficiency, IgG1-IgG2-IgG4 deficiency and IgG2-IgG4 deficiency each in 1). The incidence of IgG subclass deficiencies was in the sequence as follows: IgG1, 20%; IgG2, 10%; IgG3, 8.6% and IgG4, 4.3%. The results suggest that IgG subclass deficiency indicate a common disorder in children with recurrent respiratory tract infections.

[The relationship between protection of regenerating rat liver against carbon tetrachloride and change of its mitochondrial respiratory activity]

Protection of regenerating rat liver against carbon tetrachloride (CCl4) poisoning 96 h after partial hepatectomy was observed, and the respiratory activity of its mitochondria was determined by using oxygen electrode method. The results were as follows: (1) Mortality in partial hepatectomized rats (PHR) caused by CCl4 (50%, 10 ml/kg) was reduced significantly as compared with sham operated rats. (2) Following hepatic damage induced by CCl4 (50%, 5 ml/kg), the levels of serum bilirubin and sGPT in PHR were significantly lower than those in sham operated rats. Histological examination of the liver also showed a significant extent of repair. (3) Respiratory activity of regenerating liver mitochondria in PHR with or without CCl4 poisoning was higher than that in sham operated rats, and the respiratory activity went parallel with the degree of repair of histological damage, the reduction of serum bilirubin, sGPT and mortality. The results mentioned above indicate that increase of respiratory activity of regenerating liver mitochondria and resistance to CCl4 may play an important role in the protection of regenerating liver against CCl4.

Study of normal and cancerous urine using photoacoustic spectroscopy

Photoacoustic spectroscopy (PAS) is a valuable technique, increasingly applied in clinical and biological analysis. Light absorption properties of urine and body tissue can be obtained more easily by the PAS technique because of its high sensitivity, than by the conventional optical techniques. By observing their absorption properties it is possible to diagnose some diseases and in this study we have used PAS to assess cancerous changes in urine and tissue. Three groups were studied: normal individuals; patients with cancer; and patients with cancer and subsequent inflammation; and the characteristic light absorption peaks obtained for a certain band (240-420 nm). These results were compared with the clinical diagnosis and proved consistent and reliable for the diagnosis of urinary tract cancer subsequently confirmed by operation. This method will probably be a useful tool for the early clinical diagnosis of cancer of the urinary system.

[The effects of pulsatile pumping on tissue perfusion and renal function during deep hypothermic low flow perfusion]

The effects of pulsatile pumping on tissue perfusion and renal function during deep hypothermic low flow perfusion were compared with non-pulsatile pumping. Twelve dogs were classified into 2 groups by the perfusion technique used. Animals were core cooled to 20 degrees C esophageal temperature with 80 ml/kg/min perfusion rate and maintained at the level for 2 hours with low flow perfusion (LFP) (30 ml/kg/min), then rewarmed to 35 degrees C with 80 ml/kg/min flow rate. As compared with the non-pulsatile group, pulsatile group demonstrated greater urine output during rewarming (p less than 0.05) and greater lymph flow during core cooling (p less than 0.05). The non-pulsatile group showed higher lymph/plasma protein concentration ratio (Lc/Pc) during LFP and rewarming (p less than 0.05), and greater plasma protein clearance during rewarming (p less than 0.05), and much higher increase of interstitial fluid pressure. The lesser water retention during bypass was also noted in the pulsatile group (28.6 +/- 27.6 ml/kg vs 85.4 +/- 52.1 ml/kg, p less than 0.05). These findings have suggested that the pulsatile perfusion may be useful for the infant cardiopulmonary bypass reducing tissue edema and preserving better renal function.

[Effects of indomethacin on 45Ca uptake and membrane fluidity of mitochondria and microsomes from rat liver]

We have reported previously that indomethacin-pretreatment could induce marked hepatic protection in rats. The present work reported effects of indomethacin on calcium regulation and membrane fluidity of mitochondria and microsomes of hepatocytes. The results showed that calcium uptake and membrane fluidity increased significantly in mitochondria and microsomes of hepatocytes isolated from the rats pretreated with indomethacin in vivo as compared with that from the control; adding indomethacin directly to isolated mitochondria and microsomes from normal rats in vitro, on the contrary, decreased membrane fluidity. These changes may be related to the protective effect of indomethacin.

Immunoglobulin G subclasses in serum and circulating immune complexes in patients with Kawasaki syndrome

IgG subclass concentrations in sera of 17 patients with Kawasaki syndrome were determined. Significantly increased IgG1 (P less than 0.001) and IgG3 (P less than 0.001) were found in the patients compared with 22 age-matched healthy children, whereas IgG2 and IgG4 were normal or slightly decreased. IgG immune complexes were measured by protein A-enzyme-linked immunosorbent assay (ELISA) combined polyethylene glycol precipitations. Eight of 17 patients (47.1%) were found to have circulating immune complexes (CIC) values above the normal control range (geometric mean +2 SD). IgG subclass composition in CIC was analyzed. The subclasses in CIC were predominantly IgG1 and IgG3. Because the antibody responses to different antigens exhibit IgG subclass restriction, it would suggest that the change of serum and CIC IgG subclasses in Kawasaki syndrome may have relevance to the pathogenesis of the disease.

Dose-dependent emergence of preneoplastic foci in rat livers after exposure to 2-nitropropane

Male and female Sprague-Dawley rats, 4-6 days old were exposed for 3 weeks (6 h/day, 5 days/week) to 2-nitropropane vapours of 0, 25, 40, 50, 80 and 125 ppm. One week later polychlorinated biphenyls (Clophen A50, 10 mg/kg body weight) were administered for promotion twice a week for 8 weeks. Thirteen weeks after starting the experiments the logarithms of the numbers of preneoplastic liver foci deficient in adenosine-5'-triphosphatase were found to be linearly related to the exposure concentrations of 2-nitropropane. Male rats exhibited an approximately four times lower foci incidence than females.

[Observing cytoprotection of indomethacin on primary cultured hepatocytes of rats]

We observed previously that indomethacin induced hepatic protection against CCl4 and galactosamine in rats. In this work we further investigated this phenomenon on primary cultured rat hepatocytes. The results showed that cultured hepatocytes of rats pretreated with indomethacin in vivo still retained the ability resisting CCl4-induced cytotoxicity, as indicated by lower leakage of enzymes. However, cultured hepatocytes of normal rats treated with indomethacin in vitro had no obvious resistance to CCl4-induced cytotoxicity. The results suggest that indomethacin pretreatment in vivo enables hepatocytes to resist injury, which probably also needs participation of other factors.

Hemodynamic changes during acute pancreatitis and the dopamine therapy

A dog model was used to measure the hemodynamic changes in acute pancreatitis (AP) caused by intraductal injection of fresh trypsin-bile mixture and to investigate the efficacy of dopamine in the treatment of AP. Dopamine was administered intravenously for 3 hours at a dose of 0.6 mg/kg/hour starting 10 min after the induction of AP. Hemorrhagic pancreatitis was characterized by a fall in cardiac output (CO), systemic arterial pressure (SAP), an increase in pulmonary vascular resistance (PVR), systemic vascular resistance (SVR) and the development of early reduction of pancreatic blood flow (PBF). Administration of dopamine produced a significant increase in PBF and leads to a normalization in CO, SAP, PVR and SVR. In addition, dopamine significantly reduced the severity of the AP, as assessed by histological staging and mortality rate. These results suggest that dopamine can limit the progression from edematous to hemorrhagic pancreatitis and prevent irreversible pancreatic damage through preserving PBF at the early phase of AP.

[Von Willebrand factor in acute leukemia]

Using Laurell's rocket and crossed immunoelectrophoresis, we studied the function of vWF on the basis of its quantity and quality. The ristocetin-induced platelet aggregation was also investigated. The results revealed that the level of plasma vWF:Ag in acute leukemia (88.53 +/- 46.33%) was significantly higher than that in normal controls (90.53 +/- 29.54%) (P less than 0.01) and markedly decreased as these cases were in partial or complete remission (105.29 +/- 26.65%) (P less than 0.01), but there were no significant differences between the cases with (204.76 +/- 68.17%) and those without bleeding tendency (174.77 +/- 65.78%), nor between ALL (185.22 +/- 62.19%) and ANLL (192.43 +/- 77.97%) (P greater than 0.05). Compared with normal controls, crossed immunoelectrophoresis of plasma vWF in 21 cases showed a rapid migration of the precipitin arcs toward the positive pole in 16 cases. This indicates that there is a relatively increased amount of small multimers in the plasma, which do not have the active function of vWF so that the ristocetin-induced aggregation was reduced or even absent in those 21 cases (the maximum aggregation rate was 62.89 +/- 34.02% in the patients and 104.69 +/- 12.13% in normal controls (P less than 0.01). The possible mechanism and clinical significance of these changes are discussed.

Superoxide dismutase: fluctuations in the structure and solvation of the active site channel studied by molecular dynamics simulation

The molecular dynamics (MD) simulation of superoxide dismutase (SOD) in water is carried out for a total of 23 ps. The simulation system is a 26 A sphere centered at the active site of SOD, including 1602 atoms from SOD and 1761 water molecules. There is no gross deviation from the x-ray structure for the average MD structure. The structure and potential fluctuations around the active site are examined. The results provide new insight to the interactions between SOD and its substrate superoxide.