Study on the isentropic equations of nucleotide sequences and their application

The tetrahedral representation of DNA sequences and its applications have been studied by many authors. In this paper we study the isentropic equations of DNA sequences and their application. First, the DNA sequence entropy is introduced, and the entropy current and divergence are defined. Second, the isentropic equations are deduced and the isentropic curves on the three coordinate planes are respectively drawn by a computer. Third, an analysis is given on the entropy distribution on the coordinate planes. Finally, we make use of the results to discuss the relationship of the fastest increasing directions of the entropy for the cytochrome c genes of seven species.

Changes in intrahepatic portal hemodynamic in early stage hepatic abscesses

Color Doppler sonography was used to investigate the changes in intrahepatic portal hemodynamics in early stage hepatic abscesses (21 lesions). At time of patients' admission, 10 lesions measuring over 6 cm showed reverse flow from at least one of their corresponding segmental portal branches, but 11 lesions measuring 6 cm or less did not show this phenomenon. All portal branches with reverse flow eventually returned to a normal direction of flow after successful medication. In conclusion, a large early stage hepatic abscess may show temporary reverse portal flow on color imaging. Thus, a differential diagnosis of hepatic tumors with reverse portal flow should include early stage hepatic abscesses.

Pharmacology and efficacy of liposome-entrapped albendazole in experimental secondary alveolar echinococcosis and effect of co-administration with cimetidine

Encapsulation of the benzimidazole albendazole in multilamellar liposomes results in a preparation in which this normally insoluble anti-hydatid drug is well solublilized in aqueous media. The high entrapment efficiency observed (75-87%) and the stability of the formulation make this a promising delivery vehicle for improved chemotherapy with albendazole. In particular, the high degree of association with phospholipid may give rise to increased oral bioavailability. Oral administration of albendazole in liposomes led to increased concentration and/or altered metabolism of albendazole sulphoxide (ABZSX) in liver and/or plasma in non-infected Wistar rats. Results from experiments using cotton rats (Sigmodon hispidus) infected with metacestodes of Echinococcus multilocularis show that entrapment within liposomes clearly increases the uptake of albendazole via the oral route. This was reflected by increased levels of albendazole and the two major metabolites in plasma, liver and cyst homogenate when a dose of liposomal albendazole (35 mg/kg) was given orally compared to free albendazole at 50 mg/kg. There was a 75-94% reduction in biomass of the metacestode and a significant increase in survival time for the animals treated with liposome entrapped albendazole. A clear difference in distribution of albendazole and its metabolites in the liver and the metacestode tissues in the presence of cimetidine indicated that the latter has a profound effect on the metabolism of albendazole. There appeared to be a synergistic interaction between albendazole and cimetidine, since the metabolism of albendazole was markedly altered in the combined cimetidine/ liposome-albendazole group, and higher therapeutic effect was observed. These findings indicate potential both for improvement of treatment of larval E. multilocularis infection and for reduction of albendazole dose levels.

Neuronal Cdc2-like kinase: from cell cycle to neuronal function

Neuronal Cdc2-like kinase, Nclk, is a heterodimer of cyclin-dependent protein kinase 5 (Cdk5) and a 25-kDa essential regulatory subunit that is derived from a 35-kDa brain- and neuron-specific protein. This protein is called neuronal Cdk5 activator, p25/35nck5a. Nclk is one of the best characterized Cdc2 family kinases whose primary function is not cell cycle related. It has been suggested that this protein kinase plays important roles in neurocytoskeleton dynamics and its loss of regulation has been implicated in Alzheimer pathology. As a member of the Cdc2-like kinase family, Nclk shares many common properties with other members of the Cdc2-like kinase family. It also possesses unique characteristics that may be related to its distinct and noncell cycle related functions. The regulatory and functional properties of Nclk are reviewed in this communication.

Regulation of synaptic facilitation by postsynaptic Ca2+/CaM pathways in hippocampal CA1 neurons

1. Current- and voltage-clamp recordings with simultaneous field potential recordings were used to study the cellular and molecular mechanisms that contribute to synaptic facilitation at CA1 synapses in rat hippocampal slices. Microelectrodes used for intracellular recordings were also used to inject modulators of intracellular signal pathways into postsynaptic CA1 neurons. 2. Paired-pulse stimulation at constant stimulus intensity was used to analyze the relationship between the first evoked response (R1) and the absolute value of paired-pulse synaptic facilitation (R2-R1). The magnitudes of these two measures were inversely correlated. Compared with synapses that control motor functions, the synapses of CA1 pyramidal neurons did not exhibit accumulative synaptic facilitation during repetitive stimulation, which is often believed to be mediated by presynaptic residual Ca2+. 3. During studies on the cellular location of mechanisms contributing to synaptic facilitation, we observed that postsynaptic injections of 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetra-acetic acid or [Ala286]CaMKII281-302 [a Ca2+/calmodulin-dependent protein kinase II (CaM-KII) inhibitor peptide] prevented the decreases in paired-pulse facilitation (PPF) and synaptic potentiation induced by elevating extracellular Ca2+. These results show that raising extracellular Ca2+ enhances synaptic transmission in part by activating postsynaptic Ca2+ signal pathways. 4. The injection of Ca2+/calmodulin (CaM) into postsynaptic neurons significantly decreased PPF in 50 of 57 experiments while inducing synaptic potentiation; the Ca2+/CaM-induced synaptic potentiation and PPF attenuation occluded subsequent high Ca(2+)-induced enhancements of synaptic transmission. The changes in PPF induced by postsynaptic injections of Ca2+/CaM were inversely correlated with R1 potentiation. 5. The decreases in PPF induced by postsynaptic Ca2+/CaM injections were prevented by coinjecting pseudosubstrate inhibitors or substrate peptides of CaM-KII and protein kinase C (PKC), and were reversed by subsequent application of cyclothiazide (a blocker of alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid receptor desensitization). 6. Our results reveal that postsynaptic Ca2+/CaM signal pathways can modulate synaptic facilitation in the CNS, and the activities of CaM-KII and PKC are involved in this modulation. The physiological significance of such modulation is that synaptic strength could be potentiated by activation of Ca2+/CaM pathways during integration of important sensory input (e.g., learning and memory), whereas decreases in synaptic facilitation may protect synaptic transmission during extreme stimulation so that neuronal signal mechanisms can more accurately code neural information.

Melioidosis: two indigenous cases in Taiwan

We report the first two indigenously acquired cases of melioidosis in Taiwan, diagnosed by positive culture and biochemically identified using the ID 32 GN system (BioMerieux Vitek Inc, Hazelwood, MO, USA). The first patient was a 75-year-old Chinese woman who had not travelled abroad since her arrival from mainland China (San-Tung province) 47 years ago. She presented with spontaneous bacterial peritonitis and hepatitis C-related liver cirrhosis with septic shock. Burkholderia pseudomallei (formerly Pseudomonas pseudomallei) was isolated from cultures of both blood and ascites fluid. The second patient, a 70-year-old Chinese man, presented with right lower lobar pneumonia complicated with empyema and septic shock. Blood cultures grew B. pseudomallei. Both patients had underlying diabetes mellitus; one also had liver cirrhosis and chronic renal failure, while the other had a renal stone. The first patient died of refractory septic shock prior to diagnosis. The second patient survived with the use of intravenous ceftazidime for 30 days, followed by oral amoxicillin-clavulanic acid for a further 3 months. These cases serve as a reminder to clinical physicians that melioidosis is now no longer exclusive to patients with a history of travel to endemic areas. A high index of clinical suspicion is required for early diagnosis and treatment in order to reduce the mortality and improve clinical outcome.

Longitudinal study of intrahepatic portal flow: a novel approach using Doppler technique

The present study investigates whether the application of the summation of portal blood flow (SPBF), measured from the left umbilical portion and the right anterior branch by Doppler, could be of use in the longitudinal study of intrahepatic portal flow or not. Forty-five subjects were divided into two groups. Group I subjects included males and post-menopausal females. Thirty-seven subjects (19 normal volunteers, 12 subjects with chronic hepatitis, six cirrhotics) were investigated by the more experienced doctor A at 9 day intervals for an intra-observer study. Among them, seven subjects (four normal volunteers, three with chronic hepatitis) were also investigated consecutively at 10 min apart by doctor B on days 1 and 10 for an interobserver study. Group II subjects included eight normal subjects with a regular menstrual cycle. They were investigated by doctor A during menstruation, mid-follicular, ovulatory and mid-luteal phases of the menstrual cycle to evaluate the possible impact of the menstrual cycle on SPBF measurement. The reproducibility of measurements was assessed by the coefficient of variation (CV) and the reproducibility coefficient. Data are expressed as mean +/- s.d. The CV of the SPBF for intra-observer and interobserver study were 4.88 +/- 3.36 and 4.19 +/- 2.53, respectively. All differences of SPBF were within their corresponding reproducibility limits. The results of SPBF measurements obtained from different phases of the menstrual cycle were variable. Only the comparison between the data obtained from mid-follicular and mid-luteal phases could demonstrate acceptable CV values (3.98 +/- 3.12%) and all the differences in SPBF measurements were within the repeatability limit. In conclusion, Doppler SPBF measurement may be useful in the longitudinal evaluation of intrahepatic portal flow changes.

Bronchial inflammation and the common cold: a comparison of atopic and non-atopic individuals

BACKGROUND

Cold virus infections are associated with asthma attacks and with increased bronchial responsiveness even in normal subjects. Possible mechanisms include epithelial damage, interaction with adhesion molecules or with T-helper cell subsets.

OBJECTIVE

To determine whether colds increase lower airway inflammation, comparing atopic with non-atopic normal subjects.

METHODS

Thirty healthy volunteers (15 atopic) took part. Baseline tests included viral serology, microbiological culture and polymerase chain reaction for rhinovirus infection (HRV-PCR), histamine bronchial provocation and bronchoscopy. Twenty subjects (eight atopic) underwent repeat tests when they developed a cold.

RESULTS

Forced expiratory volume in one second (FEV1) was significantly lower during colds (-0.19 L [95% confidence interval -0.10, -0.29], P = 0.0004) and there was a significant increase in bronchial responsiveness (+0.62 doublings of the dose-response slope [+0.24, +1.00], P = 0.003). Eight subjects (two atopic) had a diagnosed viral infection: two HRV, three coronavirus (HCV), one HRV + HCV, one parainfluenza III (PI) and one respiratory syncytial virus (RSV) (also Haemophilus influenzae). In biopsies, during colds, total eosinophils (EGI+) increased significantly (geometric mean 6.73-fold [1.12,40.46], P = 0.04). Activated eosinophils (EG2+) only increased significantly in the subgroup without diagnosed viral infection and particularly in atopic rhinitics. T-suppressor (CD8+) cells also increased significantly (median + 178.3 cells mm2, P = 0.004). Epithelial expression of intercellular adhesion molecule-1 (ICAM-1) expression increased in four atopic rhinitics during colds. Bronchial washings showed a significant increase in neutrophils (GM 1.53-fold [1.04,2.25], P = 0.02).

CONCLUSION

Lower airway inflammation was present in atopic and non-atopic normal subjects with colds. Atopic subjects differed in that they were less likely to have positive virological tests and were more likely to show activated eosinophilia in the lower airway, despite a similar spectrum of symptoms.

Neutrophils undergo apoptosis following ingestion of Escherichia coli

Apoptosis is a distinct mechanism by which eukaryotic cells die. Neutrophils (PMN) play a fundamental role in the systemic inflammatory response syndrome. Clearance of PMN during resolution of the acute inflammatory process occurs by apoptosis, but factors inducing this process are unknown. The aims of this study were to determine whether PMN ingestion of Escherichia coli would result in PMN apoptosis and whether the mechanism was related to the respiratory burst. PMN from 10 healthy volunteers were cultured with different ratios of PMN:E. coli (1:0 to 1:25) for 12 h. Apoptosis was then assessed by propidium iodide DNA staining, morphology, gel electrophoresis, and Fc gamma RIII expression. There was a significant induction of PMN apoptosis on incubation with E. coli at a ratio of 1:10 and 1:25 PMN:E. coli as well as decreases in Fc gamma RIII. This correlated with increased ingestion of FITC-labeled E. coli and intracellular reactive oxygen intermediates after a 2-h coculture. To clarify the role of reactive oxygen intermediates in E. coli-induced PMN apoptosis, we assessed the effects of the antioxidants catalase, DMSO, glutathione, and N-acetylcysteine. There was a significant decrease in E. coli-induced PMN apoptosis on incubation with DMSO (1.0%), glutathione (25 mM), and N-acetylcysteine (25 mM) compared with control PMN:E. coli. This study demonstrates for the first time that E. coli induces PMN apoptosis through an oxygen-dependent mechanism. The removal of effete PMN by the process of apoptosis rather than necrosis may be teleologically beneficial during Gram-negative septicemia.

Neutrophils undergo apoptosis following ingestion of Escherichia coli

Apoptosis is a distinct mechanism by which eukaryotic cells die. Neutrophils (PMN) play a fundamental role in the systemic inflammatory response syndrome. Clearance of PMN during resolution of the acute inflammatory process occurs by apoptosis, but factors inducing this process are unknown. The aims of this study were to determine whether PMN ingestion of Escherichia coli would result in PMN apoptosis and whether the mechanism was related to the respiratory burst. PMN from 10 healthy volunteers were cultured with different ratios of PMN:E. coli (1:0 to 1:25) for 12 h. Apoptosis was then assessed by propidium iodide DNA staining, morphology, gel electrophoresis, and Fc gamma RIII expression. There was a significant induction of PMN apoptosis on incubation with E. coli at a ratio of 1:10 and 1:25 PMN:E. coli as well as decreases in Fc gamma RIII. This correlated with increased ingestion of FITC-labeled E. coli and intracellular reactive oxygen intermediates after a 2-h coculture. To clarify the role of reactive oxygen intermediates in E. coli-induced PMN apoptosis, we assessed the effects of the antioxidants catalase, DMSO, glutathione, and N-acetylcysteine. There was a significant decrease in E. coli-induced PMN apoptosis on incubation with DMSO (1.0%), glutathione (25 mM), and N-acetylcysteine (25 mM) compared with control PMN:E. coli. This study demonstrates for the first time that E. coli induces PMN apoptosis through an oxygen-dependent mechanism. The removal of effete PMN by the process of apoptosis rather than necrosis may be teleologically beneficial during Gram-negative septicemia.

Antihistamines: topical vs oral administration

The pathogenesis of allergic rhinitis is complex, involving not only histamine and mast cell-derived tryptase, but also eosinophil- and neutrophil-derived mediators, cytokines, and intercellular cell adhesion molecules (ICAM-1). It is surprising that antihistamines, which block only one component of the process, have proved so effective in the management of allergic rhinitis. Research has therefore focused on whether antihistamines have additional pharmacological activities. In vitro studies have shown that high concentrations of second generation antihistamines can block inflammatory mediator release from basophils and mast cells, and reduce ICAM-1 expression in epithelial cell lines. In vivo studies have also shown an effect on the allergen-induced inflammatory reaction; both oral and intranasal antihistamines cause a reduction in nasal symptoms and inflammatory cell influx. Oral terfenadine and cetirizine and intranasal levocabastine and azelastine have also demonstrated a lowering of ICAM-1 expression on epithelial cells. With regard to clinical efficacy, topical levocabastine (0.5 mg/mL eye drop solution and 0.5 mg/mL nasal spray) was shown to be more effective than oral terfenadine (60 mg twice daily) in relieving ocular itch (P = 0.02) and reducing nasal symptoms in allergic rhinoconjunctivitis. In a further study, levocabastine eye drops were as effective and well tolerated as sodium cromoglycate in seasonal allergic rhinitis. Intranasal azelastine (0.28 mg twice daily) showed a trend for superior relief of rhinorrhoea and nasal obstruction compared with oral terfenadine (60 mg twice daily). In addition, intranasal azelastine (0.28 mg twice daily) resulted in significant reductions in sneezing, nasal obstruction, rhinorrhoea and itching in perennial rhinitis, compared with the lower efficacy of beclomethasone dipropionate (0.1 mg twice daily). As well as benefits in efficacy, topical administration is associated with improved safety. Some antihistamines, particularly those metabolized in the liver, are associated with occasional reports of severe side-effects. It is therefore logical to administer antihistamines directly to the target organ.

Short-term effects of nasal pressure support ventilation in acute exacerbation of hypercapnic COPD

BACKGROUND

If nasal pressure support ventilation (NPSV) can be used at the early stage of acute exacerbation of severe COPD, profound ventilatory failure may be prevented without the complication from delayed intubation. To our knowledge, no study has focused on this group of patients.

METHODS

In this prospective study, BiPAP was used with three stages of settings each for 30 min as follows: pressure support (PS) 10 cmH2O without PEEP (stage 1), PS 10 & PEEP 5 cmH2O (stage 2), and PS 17 & PEEP 5 cmH2O (stage 3). Data of spontaneous breathing before and after NPSV each for 10 min were also recorded as baselines.

RESULTS

One of our 10 male patients dropped out due to intolerance of the mask, who was intubated immediately. Data of the other nine patients showed that integrated diaphragmatic EMG, respiratory rate, end-tidal CO2, VT/Ti, and VE reduced significantly when compared between baselines and stage 3 values (p = 0.0121, 0.0026, 0.0005, 0.0116, 0.0111 respectively). VT and SaO2 increased significantly (p = 0.0265 & 0.0019). The above parameters showed no significant difference between stage 1 and 2. Maximum inspiratory and expiratory mouth pressure remained unchanged after NPSV. No obvious complication was noted.

CONCLUSIONS

For patients with acute exacerbations of sever COPD, early and short-term use of NPSV at higher level of PS can significantly suppress inspiratory muscle activities and respiratory drive, and improve VE, respiratory rate, gas exchange and thoracoabdominal asynchrony. Respiratory muscle strength changes little. The addition of 5 cmH2O of PEEP to 10 cmH2O of PS has no obvious effect.

Shared calcium signaling pathways in the induction of long-term potentiation and synaptic disinhibition in CA1 pyramidal cell dendrites

1. Calcium signaling pathways were examined in the induction of long-term synaptic disinhibition following tetanization. Effects of tetanization on gamma-aminobutyric acid-A (GABAA receptor-mediated inhibitory responses were measured and compared with excitatory responses under experimental conditions previously used for examining induction mechanisms of N-methyl-D-aspartate (NMDA)-dependent long-term potentiation (LTP). Intracellular recordings were performed in current-clamp and discontinuous single-electrode voltage-clamp (dSEVC) modes in CA1 pyramidal cell apical dendrites in hippocampal slices of adult guinea pigs with the use of sharp electrodes. Test pulses and tetanic stimuli were applied to the Schaffer collateral fibers in stratum radiatum. 2. Under standard control conditions [3 M K Ac in the recording pipette and artificial cerebrospinal fluid as extracellular solution], tetanization-induced sustained increases of excitatory responses were accompanied by marked decreases of parameters of GABAA-mediated synaptic inhibition: at 40 min after tetanization [posttetanus 40 (PT 40)], orthodromically evoked excitatory postsynaptic potential (EPSP) peak amplitudes were on average 195 +/- 15% (mean +/- SE) and excitatory postsynaptic currents (IPSPs) were 166 +/- 10% of pretetanus controls. Peak amplitudes of orthodromically evoked inhibitory postsynaptic potentials (IPSPs) were 30 +/- 5% and inhibitory postsynaptic currents (IPSCs) were 21 +/- 4% at PT 40. Synaptic GABAA conductances (measured as chord conductances) were reduced to 22 +/- 4% at PT 40. Iontophoretic GABAA responses measured as conductance changes were 28 +/- 4% of pretetanus controls at PT 40. 3. A role of NMDA receptors in induction of long-term synaptic disinhibition was tested by preventing NMDA receptor activation 1) by pharmacological means and 2) by holding the membrane clamped at -80 mV (in dSEVC) during tetanization. In the presence of the NMDA-receptor antagonist D-2-amino5-phosphonopentanoic acid (D-AP5) 10-40 microM), orthodromically evoked EPSP amplitudes were 107 +/- 9%, EPSCs were 104 +/- 6%, GABAA-mediated IPSPs were 88 +/- 8%, IPSCs were 97 +/- 8%, synaptic GABAA conductances were 84 +/- 9%, and iontophoretic GABAA conductances were 102 +/- 13% at PT 40. In recordings in which the dendritic membrane potential was clamped at -80 mV during tetanization, orthodromically evoked peak amplitudes of EPSPs were 105 +/- 11%, EPSCs were 102 +/- 8, IPSPs were 103 +/- 4%, IPSCs were 102 +/- 5%, GABAA chord conductances were 101 +/- 9%, and iontophoretically evoked GABAA conductances were 105 +/- 5% at PT 40. 4. In recordings in which the intracellular pipette was preloaded with the Ca2+ chelator 1,2-bis(2-aminophenoxy) ethane-N,N,N'N"-tetraacetic acid (BAPTA) (5mM), long-term changes of synaptic transmission (increases of excitation, decreases of synaptic inhibition) were prevented. At PT 40, EPSP peak amplitudes were 93 +/- 7%, EPSCs were 115 +/- 6%, IPSPs were 115 +/- 9%, IPSCs were 117 +/- 8%, and synaptic GABAA conductances were 108 +/- 17%. Iontophoretic conductances at PT 40 were 109 +/- 9% over pretetanus controls when recorded with BAPTA-containing electrodes. 5. In recordings in which the intracellular pipette was preloaded with cypermethrin, a potent and selective inhibitor of phosphatase 2B, respective long-term changes of synaptic transmission (increases of excitation, decreases of synaptic inhibition) were prevented. At PT 40, EPSP peak amplitudes were 98 +/- 6%, EPSCs were 105 +/- 10%, IPSPs were 99 +/- 5%, IPSCs were 104 +/- 7%, synaptic GABAA conductances were 97 +/- 6% and iontophoretic GABAA conductances were 113 +/- 18% over pretetanus controls in cypermethrin-containing recordings. 6. In conclusion, the data presented demonstrate shared cellular pathways in the induction of both LTP and long-term synaptic disinhibition in apical dendrites of CA1 pyramidal cells after tetanization of the Schaffer collaterals.

LYS-49 phospholipase A2 homologs from venoms of Deinagkistrodon acutus and Trimeresurus mucrosquamatus have identical protein sequence

The complete amino acid sequences of the Lys-49 PLA2s from the venom of Deinagkistrodon acutus (from Taiwan and China) and Trimeresurus mucrosquamatus (Taiwan habu) were solved by a facile cDNA cloning and sequencing method. The deduced amino acid sequences of the Lys-49 PLA2s of both venoms are identical, suggesting close phylogenic relationship between this two snake species of different genera. In addition, by cloning and cDNA sequencing, the mRNA coding for a Arg-49 PLA2 homolog of low expression level was also found in the venom gland of T. mucrosquamatus.

Demonstration of cyclin-dependent kinase inhibitory serine/threonine kinase in bovine thymus

A synthetic peptide corresponding in sequence to residues 6-20 of p34cdc2, cdc2(6-20), and a substitution analogue, cdc2(6-20)F15K19 , which contains Thr-14 as the only phosphorylation target were used as substrates to identify a novel protein kinase in bovine thymus cytosol. The kinase catalyzed the phosphorylation of Thr-14 in both peptides and was purified extensively on the basis of its peptide phosphorylation activity. Upon SDS-polyacrylamide gel electrophoresis analyses, the purified samples consistently displayed a prominent 43-kDa protein band which could undergo in gel autophosphorylation, thus suggesting that this band represented the kinase protein. The suggestion was supported further by the observation that both cdc2(6-20) peptide phosphorylation and the autophosphorylation reaction of the 43-kDa protein were inhibited by millimolar concentrations of cAMP. The kinase was found to inactivate Cdc2/cyclin B, Cdk2/cyclin A, and neuronal Cdc2-like kinase (Nclk), a heterodimer of Cdk5 and neuronal Cdk5 activator (Nck5a), under phosphorylation conditions. The phosphorylation of Nclk by the purified thymus kinase occurred on Cdk5. The monomeric form of Cdk5 was also phosphorylated by the kinase. Phosphoamino acid and phosphopeptide analysis of the phosphorylated Nclk revealed that Thr-14 of Cdk5 was the sole site of protein phosphorylation. The results suggest that this thymus kinase is a novel Cdk inhibitory protein kinase, distinct from the recently cloned dual functional and membrane-associated Cdc2 inhibitory kinase, Myt1 (Mueller, P. R., Coleman, T. R., Kumagai, A., and Durphy, W. G. (1995) Science 270, 86-90).

A study of the association between squamous cell carcinoma and adenocarcinoma in the lung, and history of menstruation in Shanghai women, China

The menstrual history of 162 cases of female lung adenocarcinoma and 19 cases of squamous cell carcinoma was compared with 187 age-matched female controls, and analyzed for statistical significant differences that may exist between the two groups using the Epi-infor program, the Chi-square test, and the Bartlett test for homogeneity of variance. Parameters related to menstrual history included: age of menarche, menstrual cycle, number of days of menstrual period, amount of menstrual flow, menstrual pain, breast bloating/tenderness, and total number of menstrual cycles prior to menopause or diagnosis of lung cancer. The results show that cases of squamous cell carcinoma have a higher total number of menstrual cycles than controls, raising the possibility that estrogen may play a role in the induction of squamous cell carcinoma. Cases with adenocarcinoma were found to have shorter menstrual periods than controls, suggesting that activity of the corpus luteum may be related to the occurrence of adenocarcinoma. Progesterone (PR) and estrogen (ER) receptor levels were also measured in 21 adenocarcinoma surgical specimens. A positive ER and PR receptor expression was correlated with later menarche and earlier menopause.

On the characteristics of the quadratic order associative memory that uses synchronous update and direct convergence

A statistical method is applied to explore the characteristics of a certain class of quadratic order associative memories: the Synchronous Update Direct Convergence Memory (SQDM). The initial input vector is required to converge, with a given value of probability Pdc, to a stored codeword in just one synchronous update. The memory capacity ms is derived by a figure of merit N phi, and its tight asymptotic bound is found by using Tchebycheff's inequality. When the input contains erroneous bits, the maximum allowable number of attractors and their attraction radii are determined. The existence of principal connections Tpr useful in solving the problem of proliferation of connections in the SQDM is introduced. We proved that Tpr is a set of which an arbitrary connection Tijk satisfies square root of ms < or = [Tijk[ < or = 2 square root of ms.

Structure of a Functional Fragment of VCAM-1 Refined at 1.9 Å Resolution

The crystal structure of the functional amino-terminal two-domain fragment of human vascular cell adhesion molecule 1 (VCAM-1) has been determined at 1.9 A resolution. The crystals contain two copies of the molecule in the asymmetric unit. The structure was solved by multiple isomorphous replacement, using lead and selenium derivatives. Anomalous scattering had to be used to resolve the phase ambiguity of a lead derivative. Since the selenium derivative has very small isomorphous differences, the local scaling algorithm had to be used to obtain an interpretable difference Patterson map. The initial phases were improved by non-crystallographic averaging, solvent flattening and histogram matching. The structure has been refined to a crystallographic R factor of 20.4% (15-1.9 A, F>/= 3sigma) and consists of two Ig domains (D1 and D2). The angle between these domains differs by 12 degrees between the two copies of the molecule in the crystallographic asymmetric unit, demonstrating that some movement is possible at the interface. In the amino-terminal domain D1 there is an 'extra' disulfide bond, in addition to the conserved cross-sheet disulfide bond, at the top of the molecule. This bond, a hallmark of the integrin-binding subclass of Ig superfamily proteins, makes the top of this domain very compact. The feature that projects most prominently from D1 is the CD loop, near the base of the domain. The key residue for integrin binding, Asp40, is located in this loop and is easily accessible.

Mechanisms involved in the induction of human endothelial cell necrosis

The effects of the inflammatory mediators lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF) and unstimulated and activated neutrophils (PMNs) on endothelial cell (EC) necrosis were studied using the cultured human EC line (ECV-304) and human PMNs in vitro. LPS and TNF alone or their combination failed to induce EC necrosis. Activated PMNs, as evidenced by augmentations in CD11b expression and respiratory burst, induced significant EC necrosis commencing at 12 hr of coculture, which was strongly dependent on the ratio of PMN:ECs and the duration of PMN:EC coculture. In contrast, unstimulated PMNs induced no significant increases in EC necrosis. To examine the mechanisms of activated PMN-mediated EC necrosis, the oxygen radical scavengers superoxide dismutase (SOD) and catalase, as well as the protease inhibitors phenylmethylsulfonyl fluoride (PMSF), alpha 1-antitrypsin (alpha 1-AT), soybean trypsin-chymotrypsin inhibitor (TCI), and aprotinin, were studied in coculture experiments. EC necrosis induced by activated PMNs could be markedly attenuated by SOD, PMSF, alpha 1-AT, TCI, aprotinin, or their combinations. Although aprotinin enhanced respiratory burst, this agent inhibited necrosis by downregulating PMN CD11b and PMN-EC adhesion. These results demonstrate that the inflammatory mediators LPS and TNF and quiescent PMNs fail to induce EC necrosis. However, PMNs activated by inflammatory mediators can induce EC necrosis through oxidative and nonoxidative mechanisms and this process is dependent on PMN-EC adhesion.

Inhibitors of poly(ADP-ribose) polymerase block nitric oxide-induced apoptosis but not differentiation in human leukemia HL-60 cells

Previous studies have shown that chemically generated nitric oxide (NO) can induce human leukemia HL-60 cells to undergo monocytic differentiation. We show here that exposure of HL-60 cells to chemical NO generators induces cell death via apoptosis which was examined by morphological and biochemical criteria. The activation of poly(ADP-ribose) polymerase (pADPRp) was found to occur during the process of cell death. The NO-induced apoptosis of HL-60 cells was effectively prevented by the ADP-ribosylation inhibitors nicotinamide (NA) and 3-aminobenzamide (3-AB). Since NO not only induced apoptosis but also triggered differentiation under the same concentration, we thus examined whether pADPRp participated in monocytic differentiation. It is of interest to note that the NO-mediated monocytic differentiation was not affected by 3-AB or NA. These findings indicate that activation of pADPRp is specifically involved in NO-induced apoptosis but not differentiation.

Percutaneous intravascular ethanol injection of the supplying tumor vessel in the treatment of hepatocellular carcinoma larger than 3 cm

Percutaneous intravascular ethanol injection of the supplying vessel of the tumor using color Doppler imaging was performed in three patients (three lesions) with hepatocellular carcinoma measuring more than 3 cm. Intravascular injection was achieved in six out ot seven attempts. The total amount of ethanol injected intravascularly was small (10, 15,0 and 26 ml for each patient). One attempt failed and the ethanol was injected perivascularly. No serious complication was noted. After treatment, two patients showed remarkable decrease in tumor size and one showed massive tumor necrosis. In conclusion, ethanol injection using the intravascular approach may be of value in the palliative management of large hepatocellular carcinomas.

Urinary PCO2 for hemodynamically unstable patients

BACKGROUND

Gastric intramural pH (pHi) derived from gastric PCO2 has been successfully used to assess splanchnic ischemia for patients with unstable hemodynamics, but with some limitations. Urinary bladder, also an easily accessible hollow viscus, should provide as a useful route for the same purpose. However, no study has used urinary PCO2 to evaluate the adequacy of perfusion in critically ill patients.

METHODS

Fifty patients admitted to intensive care unit were included and divided into hemodynamically stable and unstable groups. Several parameters such as arterial pressure, dopamine dosage, heart rate, serum lactate, arterial blood gas, urinary PCO2, and concentrations of Na, K and Cl in urine were measured. Patients with some other renal or pre-renal conditions that might affect urinary PCO2 were excluded.

RESULTS

Urinary PCO2 was markedly higher (78.6 +/- 9.9 vs. 43.1 +/- 1.7 mmHg, p < 0.0001) in unstable group. Serum anion gap level, dopamine dosage and heart rate were significantly higher and PaO2/FiO2 ratio as well as mean arterial pressure was lower in unstable group. Serum lactate, arterial pH and other parameters failed to distinguish between groups. Dopamine dosage significantly correlated with urinary PCO2 (r = 0.5357, p = 0.0149) in unstable group.

CONCLUSIONS

With careful selection of patients, urinary PCO2 can effectively differentiate hemodynamically unstable patients from stable ones. It also correlates significantly with dopamine dosage in patients with unstable hemodynamics.

Interaction of cyclin-dependent kinase 5 (Cdk5) and neuronal Cdk5 activator in bovine brain

Neuronal cdc2-like kinase (Nclk) purified from bovine brain is a heterodimer of Cdk5 and an essential 25-kDa regulatory subunit (Lew, J., and Wang, J. H. (1995) Trends Biochem. Sci. 20, 33-37). The regulatory subunit is an N-terminal truncated derivative of a 35-kDa protein expressed specifically in brain, hence the name neuronal Cdk5 activator, p25/p35nck5a. In this study, we probe the relationship between the two different forms of Nck5a and their interaction with and activation of Cdk5 in bovine brain extract. Using protein fractionation procedures in combination with Western blot analysis and protein kinase assay, three forms of Cdk5 have been detected in bovine brain: a monomeric Cdk5 that can be activated by bacterially expressed GST-p21nck5a, a heterodimer of Cdk5 and p25nck5a that displays high kinase activity, and a Cdk5.p35nck5a complex that is inactive and refractory to GST-p21nck5a activation. Analysis of the Cdk5.p35nck5a complex by gel filtration chromatography indicated that the complex was part of a macromolecular structure with a molecular mass of approximately 670 kDa. When the macromolecular complex was subjected to gel filtration chromatography in the presence of 10% ethylene glycol, the fractions containing both p35nck5a and Cdk5, although eluting at the same position as control, displayed high kinase activity. The result is compatible with the suggestion that the macromolecular complex contained a kinase inhibitory factor that dissociated from the complex in 10% ethylene glycol.

A novel yeast protein showing specific association with the cyclin-dependent kinase 5

The present study describes a significant amino acid sequence homology between neuronal Cdk5 activator (nck5a) and an open reading frame of an unknown gene on the yeast S. cerevisiae chromosome III. A cDNA encoding a 25 kDa fragment of this yeast protein, the region containing homologous sequence to nck5a was cloned and expressed in E. coli as a glutathine-S-transferase fusion protein (GST-p25Y). GST-p25Y was found to block the in vitro activation of Cdk5 by nck5a and to affinity precipitate Cdk5 from bovine brain extract. The observations indicate that the yeast protein is capable of specific and high affinity association with Cdk5.