[Microsatellite instability in urine sediments from patients with transitional cell carcinoma of bladder and its clinical value]

OBJECTIVE

To investigate the expression of microsatellite instability in transitional cell carcinoma of bladder and to detect its diagnostic value.

METHODS

Urine samples from 35 patients with transitional cell carcinoma of bladder (TCC) were analyzed by PCR method. 25 patients were followed up to detect microsatellite instability in their urine sediments.

RESULTS

Microsatellite changes (including MSI and LOH) were detected in 88.6% of urine sediments (31 of 35 patients). Microsatellite changes were detected in urine sediments of 10 of 12 patients with tumor recurrence, in which the existence of tumor cells in the urine of 3 patients had been correctly predicted before cystoscopic evidence from 3 to 6 months. CONCLUSION Microsatellite analysis of urine sediment may be a novel and potentially clinical tool for the diagnosis and follow-up of bladder cancer patients.

Mutational analyses of restriction endonuclease-HindIII mutant E86K with higher activity and altered specificity

We have performed mutational analyses of restriction endonuclease HindIII in order to identify the amino acid residues responsible for enzyme activity. Four of the seven HindIII mutants, which had His-tag sequences at the N-termini, were expressed in Escherichia coli, and purified to homogeneity. The His-tag sequence did not affect enzyme activity, whereas it hindered binding of the DNA probe in gel retardation assays. A mutant E86K in which Lys was substituted for Glu at residue 86 exhibited high endonuclease activity. Gel retardation assays showed high affinity of this mutant to the DNA probe. Surprisingly, in the presence of a transition metal, Mo(2+) or Mn(2+), the E86K mutant cleaved substrate DNA at a site other than HindIII. Substitution of Glu for Val at residue 106 (V106E), and Asn for Lys at residue 125 (K125N) resulted in a decrease in both endonucleolytic and DNA binding activities of the enzyme. Furthermore, substitution of Leu for Asp at residue 108 (D108L) abolished both HindIII endonuclease and DNA binding activities. CD spectra of the wild type and the two mutants, E86K and D108L, were similar to each other, suggesting that there was little change in conformation as a result of the mutations. These results account for the notion that Asp108 could be directly involved in HindIII catalytic function, and that the substitution at residue 86 may bring about new interactions between DNA and cations.

Different Wnt-5A gene expressions in the renal cell carcinoma GRC-1 cell line during the cell cycle

OBJECTIVE

To investigate the gene expression at transcription level of growth factor Wnt-5A in different phase during the cell cycle.

METHODS

We synchronized the renal cell carcinoma GRC-1 cell line by double thymidine blocks and high-pressure N2O gae methods and amplified Wnt-5A cDNAs from different phase using Semi-quantitative RT-PCR (reverse transcriptase polymerase chain reaction). The PCR products were electrophoresized on the agrose gel and detected by Gel Doc 1000 computer controlled system integrating the volumes of each band, representing the intensities of all pixels in a defined band.

RESULTS

The different mRNA expressions of growth factor Wnt-5A was detected in RCC GRC-1 cell line. In S phase, the highest level of Wnt-5A transcript was observed, and in G1 and M phase, medial and lowest, respectively. The differences between S and M stages were statistically significant (P < 0.05).

CONCLUSION

Growth factor Wnt-5A has the potential effect on tumorigenesis. It contributes to all phases during cell cycle but in S phase especially.

Caspase-8 activation and bid cleavage contribute to MCF7 cellular execution in a caspase-3-dependent manner during staurosporine-mediated apoptosis

There are at least two distinct classes of caspases, initiators (e.g. caspases-8, -9, and -10) and effectors (e.g. caspase-3). Furthermore, it is believed that there are two distinct primary apoptotic signaling pathways, one of which is mediated by death receptors controlled by caspases-8/10, and the other by the release of cytochrome c and activation of a caspase-9/Apaf1/cytochrome c apoptosome. However, several recent reports have demonstrated that caspase-8, and its substrate Bid, are frequently activated in response to certain apoptotic stimuli in a death receptor-independent manner. These results suggest that significant cross-talk may exist between these two distinct signaling arms, allowing each to take advantage of elements unique to the other. Here we provide evidence that activation of caspase-8, and subsequent Bid cleavage, does indeed participate in cytochrome c-mediated apoptosis, at least in certain circumstances and cell types. Furthermore, the participation of activated caspase-3 is essential for activation of caspase-8 and Bid processing to occur. Although caspase-8 activation is not required for the execution of a cytochrome c-mediated death signal, we found that it greatly shortens the execution time. Thus, caspase-8 involvement in cytochrome c-mediated cell death may help to amplify weaker death signals and ensure that apoptosis occurs within a certain time frame.

[Influence of dietary habits and body weight on blood uric acid in the elderly]

Influence of dietary habits, body weight on blood uric acid was studied in 416 elderly people. The result showed that level of blood uric acid in the people who had habits of drinking alcohol, tea and taking hot foods was higher than that who never had those habits (P < 0.05 or 0.01). It also showed that level of blood uric acid was significantly increased in the over-weight or obesity people (P < 0.05). The hyperuricemia incidence in the over-weight or obesity people is 27.4 per cent, and it is 2 times and 3.4 times of the people with ideal weight and weak-weight, respectively. It is suggested that the patients with gout or hyperuricemia give up drinking alcohol, tea and taking hot foods for their health. Reducing body weight is one of the effective measures to prevent and treat gout or hyperuricemia in the elderly.

Bundling of microtubules in the growth cone induced by laminin

Axons growing in the developing nervous system are guided by cues in the environment which act at the growth cone. So far, the initial cytoskeletal target of these cues has been found to be the network of actin filaments in the peripheral region of the growth cone. Laminins are constituents of the extracellular matrix which promote axonal growth. They exert effects on the actin network. Here, laminin 1 is shown to affect microtubules as well. Acute addition of laminin 1 to rat sympathetic neurons quickly caused the advance of microtubules and their bundling within the initial widely spread growth cone and then the outgrowth of thin, rapidly growing nascent axons. The bundling was pharmacologically separable from the advance of microtubules caused by laminin, as the former but not the latter was blocked by lithium. The bundling did not depend on the peripheral network of actin filaments, as it was unimpaired by the removal of this network with cytochalasin D. Thus, microtubules seem to be a direct cytoskeletal target for laminin 1 in the growth cone, with important consequences for axonal outgrowth.

GSH transport in human cerebrovascular endothelial cells and human astrocytes: evidence for luminal localization of Na+-dependent GSH transport in HCEC

The purpose of the present study was to identify and localize glutathione (GSH) transport in an in vitro tissue culture model of blood-brain barrier (BBB). The localization of Na+-dependent GSH transport in an immortalized cell line of human cerebrovascular endothelial cells (HCEC) and asymmetry of transport in Transwell studies were investigated. Initial studies with cultured HCEC established a significant (45%) Na+-dependency for GSH uptake in cultured HCEC pretreated with acivicin, an inhibitor of gamma-glutamyltranspeptidase (GGT). Transendothelial electrical resistance (TEER) and uptake of [35S]GSH from luminal and abluminal fluids of HCEC were measured in Na+-containing and Na+-free (choline chloride) buffers using cells grown on gelatin-coated membrane filters. TEER of HCEC monolayers in regular medium was 40.1 +/- 8.0 ohms cm2. Human astrocyte-conditioned medium (ACM) caused no change in TEER, but increased GGT activity approximately threefold when measured in cell lysates. Luminal and abluminal GSH uptake increased in a time-dependent fashion and were not affected by inhibition of GGT activity with acivicin. Sodium dependency was only observed for luminal uptake (Na+-containing 2.41 +/- 0.15 vs. Na+-free 0.96 +/- 0.03 pmol/30 min/million cells, p < 0.001) but not for abluminal uptake (1.02 +/- 0.13 vs. 1.11 +/- 09, p > 0.05). Apparent efflux via the luminal membrane was lower in the presence of sodium as compared to that without sodium, further suggesting that a Na+-dependent uptake process for GSH is operative at this membrane. GSH uptake and efflux were also demonstrated in neonatal rat and fetal human astrocytes, both exhibiting partial Na+-dependency of uptake. In conclusion, our results show for the first time, that HCEC and astrocytes take up GSH by both Na+-dependent and -independent mechanisms. The Na+-dependent GSH transport process in HCEC appears to be localized to luminal plasma membranes of HCEC.

A nonlinear axisymmetric model with fluid-wall interactions for steady viscous flow in stenotic elastic tubes

Arteries with high-grade stenoses may compress under physiologic conditions due to negative transmural pressure caused by high-velocity flow passing through the stenoses. To quantify the compressive conditions near the stenosis, a nonlinear axisymmetric model with fluid-wall interactions is introduced to simulate the viscous flow in a compliant stenotic tube. The nonlinear elastic properties of the tube (tube law) are measured experimentally and used in the model. The model is solved using ADINA (Automatic Dynamic Incremental Nonlinear Analysis), which is a finite element package capable of solving problems with fluid-structure interactions. Our results indicate that severe stenoses cause critical flow conditions such as negative pressure and high and low shear stresses, which may be related to artery compression, plaque cap rupture, platelet activation, and thrombus formation. The pressure filed near a stenosis has a complex pattern not seen in one-dimensional models. Negative transmural pressure as low as -24 mmHg for a 78 percent stenosis by diameter is observed at the throat of the stenosis for a downstream pressure of 30 mmHg. Maximum shear stress as a high as 1860 dyn/cm2 occurs at the throat of the stenoses, while low shear stress with reversed direction is observed right distal to the stenosis. Compressive stresses are observed inside the tube wall. The maximal principal stress and hoop stress in the 78 percent stenosis are 80 percent higher than that from the 50 percent stenosis used in our simulation. Flow rates under different pressure drop conditions are calculated and compared with experimental measurements and reasonable agreement is found for the prebuckling stage.

Alpha-crystallin/lens lipid interactions using resonance energy transfer

Resonance energy transfer was used to study the interaction of alpha-crystallin with lens cortex lipid vesicles. The binding of alpha-crystallin to cortex lipid vesicles and the preincubation temperature dependence of the binding were confirmed. In this study, the tryptophan of alpha-crystallin was used as the energy donor, and the fluorescence probe N-(5-dimethylaminonaphthalene-1-sulfonyl)-1, 2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (dansyl DHPE) was chosen as the energy acceptor. Lens cortex lipid vesicles were preincorporated with dansyl DHPE. Energy transfer from the tryptophan of alpha-crystallin to dansyl DHPE was found and the energy transfer efficiency was calculated. There was a higher energy transfer efficiency between alpha-crystallin and dansyl DHPE when alpha-crystallin was preincubated at 65 degrees C compared to 22 degrees C. Data confirmed the binding of alpha-crystallin to lens cortex lipid and showed that alpha-crystallin bound more closely to the surface of cortex vesicles when it was preincubated at a higher temperature. This is probably due to the exposure of hydrophobic surfaces when alpha-crystallin is preincubated at a higher temperature.

Lipid composition, membrane structure relationships in lens and muscle sarcoplasmic reticulum membranes

Membrane lipid composition varies in different tissues and species. Since a defined lipid composition is essential to the function of many membranes, the relationship between membrane lipid composition and structure was determined using infrared and Raman spectroscopy in four membranes containing a calcium pump: rabbit fast and slow twitch muscle sarcoplasmic reticulum and human and bovine lens fiber cell membranes. We found that membrane sphingolipid and phosphatidylcholine content were correlated to a decrease and increase, respectively, in the infrared lipid CH2 symmetric stretching band frequency. We interpret the change in frequency as a change in lipid hydrocarbon chain structural order. This was confirmed by Raman order parameters. The high degree of hydrocarbon chain saturation found in the variable amide chains of sphingolipids is likely to account for this correlation. Lipid phase transition temperature and cooperativity also correlated to sphingolipid and phosphatidylcholine content, and are the forces defining the order in at physiological temperature in the samples studied. Ca(2+)-ATPase caused an increase in the CH2 symmetric stretching frequency in fast twitch muscle sarcoplasmic reticulum (interpreted as an increase in hydrocarbon chain disorder), but had no effect on slow twitch muscle sarcoplasmic reticulum lipid hydrocarbon chain structure. In the natural systems studied, we find that it is the lipid hydrocarbon chain saturation that defines lipid hydrocarbon chain order.

Molecular and genetic damage from environmental tobacco smoke in young children

To assess the risks of early life exposure to environmental tobacco smoke (ETS), we tested whether four biomarkers in peripheral blood were associated with home ETS exposure in Hispanic and African-American children. The biomarkers included cotinine (a metabolite of nicotine) and three indicators of molecular and genetic damage from mutagens/carcinogens, protein adducts formed by the carcinogens 4-aminobiphenyl (4-ABP) and polycyclic aromatic hydrocarbons (PAHs), and sister chromatid exchanges (SCEs). We also explored possible ethnic differences in biomarkers. The study cohort comprised 109 Hispanic and African-American preschool children (1-6 years of age). Plasma cotinine was analyzed by gas chromatography, 4-ABP-hemoglobin adducts by gas chromatography-mass spectroscopy, PAH-albumin adducts by ELISA, and SCEs by cytogenetic techniques. Data on the amount of smoking by mothers (average 10.5 cigarettes per day) and other household members and regular visitors (average 6.5 cigarettes per day) were obtained by interview-administered questionnaires. Cotinine, 4-ABP-hemoglobin adducts, and PAH-albumin were significantly higher (P < 0.05) in the ETS-exposed children compared with the unexposed. SCEs were marginally higher (P = 0.076). African-American children had higher levels of cotinine (P = 0.059) and PAH-albumin (P = 0.02) than Hispanic children, after controlling for exposure to ETS. These results indicate molecular and genetic damage in minority children with

Mediated, amperometric biosensor for glucose-6-phosphate monitoring based on entrapped glucose-6-phosphate dehydrogenase, Mg2+ ions, tetracyanoquinodimethane, and nicotinamide adenine dinucleotide phosphate in carbon paste

In this study, an amperometric carbon paste biosensor is developed for glucose-6-phosphate (G6P) monitoring which is based on entrapped Mg2+ ions, G6P dehydrogenase, NADP+ polyethylenimine (PEI) and the electroactive mediator, tetracyanoquinodimethane (TCNQ). The calibration line had a slope of 1.55 x 10(-5) A. M-1 with a correlation coefficient of 0.9965. The limit of detection (defined as three times the standard deviation of the response of the electrode to blank phosphate buffer injections (noise)) of the G6P biosensor was 5.0 x 10(-5) M. The application of this biosensor for monitoring G6P in human blood using the standard addition method is also demonstrated. A two-parameter empirical equation which adequately describes the deactivation of the biosensor steady-state response with time is also proposed.

Cycloheximide-induced T-cell death is mediated by a Fas-associated death domain-dependent mechanism

Cycloheximide (CHX) can contribute to apoptotic processes, either in conjunction with another agent (e.g. tumor necrosis factor-alpha) or on its own. However, the basis of this CHX-induced apoptosis has not been clearly established. In this study, the molecular mechanisms of CHX-induced cell death were examined in two different human T-cell lines. In T-cells undergoing CHX-induced apoptosis (Jurkat), but not in T-cells resistant to the effects of CHX (CEM C7), caspase-8 and caspase-3 were activated. However, the Fas ligand was not expressed in Jurkat cells either before or after treatment with CHX, suggesting that the activation of these caspases does not involve the Fas receptor. To determine whether CHX-induced apoptosis was mediated by a Fas-associated death domain (FADD)-dependent mechanism, a FADD-DN protein was expressed in cells prior to CHX treatment. Its expression effectively inhibited CHX-induced cell death, suggesting that CHX-mediated apoptosis primarily involves a FADD-dependent mechanism. Since CHX treatment did not result in the induction of Fas or FasL, and neutralizing anti-Fas and anti-tumor necrosis factor receptor-1 antibodies did not block CHX-mediated apoptosis, these results may also indicate that FADD functions in a receptor-independent manner. Surprisingly, death effector filaments containing FADD and caspase-8 were observed during CHX treatment of Jurkat, Jurkat-FADD-DN, and CEM C7 cells, suggesting that their formation may be necessary, but not sufficient, for cell death.

Identification and structure characterization of a Cdk inhibitory peptide derived from neuronal-specific Cdk5 activator

The activation of cyclin-dependent kinase 5 (Cdk5) depends on the binding of its neuronal specific activator Nck5a. The minimal activation domain of Nck5a is located in the region of amino acid residues 150 to 291 (Tang, D., Chun, A. C. S., Zhang, M., and Wang, J. H. (1997) J. Biol. Chem. 272, 12318-12327). In this work we show that a 29-residue peptide, denoted as the alphaN peptide, encompassing amino acid residues Gln145 to Asp173 of Nck5a is capable of binding Cdk5 to result in kinase inhibition. This peptide also inhibits an active phospho-Cdk2-cyclin A complex, with a similar potency. Direct competition experiments have shown that this inhibitory peptide does not compete with Nck5a or cyclin A for Cdk5 or Cdk2, respectively. Steady state kinetic analysis has indicated that the alphaN peptide acts as a non-competitive inhibitor of Cdk5. Nck5a complex with respect to the peptide substrate. To understand the molecular basis of kinase inhibition by the peptide, we determined the structure of the peptide in solution by circular dichroism and two-dimensional 1H NMR spectroscopy. The peptide adopts an amphipathic alpha-helical structure from residues Ser149 to Arg162 which can be further stabilized by the helix-stabilizing solvent trifluoroethanol. The hydrophobic face of the helix is likely to be the kinase binding surface.

Size fractionation of bacterial capsular polysaccharides for their use in conjugate vaccines

We have developed a chromatographic method suitable for the fractionation of polysaccharides having a negatively charged group. The method permits the removal of all those polysaccharide fragments having a short sequence and which are likely unsuitable for conjugate vaccine construction. The selected polysaccharide fragments can be used to produce glycoconjugate vaccines containing a restricted saccharide polydispersion. We have applied this chromatographic method to three different antigens, Haemophilus influenzae type b and Neisseria meningitidis group A and group C polysaccharides. The method is easily adapted for manufacturing purposes.

Towards rice genome scanning by map-based AFLP fingerprinting

Map-based DNA fingerprinting with AFLP markers provides a fast method for scanning the rice genome. Three hundred AFLP markers identified with ten primer combinations were mapped in two rice populations. The genetic maps were aligned and almost full coverage of the rice genome was obtained. The transferability of AFLP markers between indica x japonica and indica x indica crosses was tested. The chromosomes were divided into DNA Fingerprint Linkage Blocks (DFLBs) defined by specific AFLP markers. Using these blocks, the degree of similarity or divergence within specific chromosome regions was calculated for nine varieties. Applications of map-based fingerprinting for biodiversity studies and maker-assisted selection are discussed.

Membrane lipid alpha-crystallin interaction and membrane Ca2+ -ATPase activities

PURPOSE

To determine the effect of alpha-crystallin binding on lens membrane lipid characteristics and the stability of Ca2+ -ATPase activity when challenged with H2O2 or elevated temperatures.

METHODS

Alpha-Crystallin binding to muscle sarcoplasmic reticulum membranes was quantified using a centrifugation protocol. Alpha-Crystallin binding to lens epithelial lipids was measured by a fluorescence energy transfer technique. Lipid phase transition temperature and lipid order was measured using fluorescence spectroscopy. Ca2+ -ATPase activity was measured using classical biochemical assays.

RESULTS

The main phase transition temperatures of multilamellar vesicles composed of sphingomyelin or lipids extracted from bovine lens were 40 degrees C and 20 degrees C, respectively. In the presence of saturating amounts of alpha-crystallin, the phase transition temperature and lipid order of both sphingomyelin and lens lipid membranes remained almost the same as that without alpha-crystallin. The interaction of alpha-crystallin and lipid is likely to be restricted to the membrane surface. The binding of alpha-crystallin did not influence the oxidative or thermal inactivation of the Ca2+ -ATPase pump.

CONCLUSION

Alpha-Crystallin-lens membrane binding does not protect the Ca2+ -ATPase pump from thermal derangement or oxidation by H2O2.

[Evaluation of biliary CEA in the diagnosis of colorectal cancer with liver metastases]

OBJECTIVE

To evaluate the clinical significance of biliary CEA for diagnosing colorectal cancer with liver metastases.

METHODS

Three groups of patients were examined: 30 patients with benign disease in group A, 30 patients with colorectal cancer in group B, and 15 colorectal cancer patients with liver metastasis in group C. Fasting venous blood was drawn, and in the meatime, bile was collected by duodenal tube drainage before operation. CEA was detected with immunosorbent assay kit supplied by Boehringer.

RESULTS

The serum level of CEA in group A, B, and C was (3.2 +/- 0.5) ng/ml, (11.7 +/- 2.4) ng/ml, and (14.8 +/- 3.5) ng/ml, respectively. The biliary CEA level was (23.7 +/- 8.6) ng/ml, (129.4 +/- 36) ng/ml, and (862 +/- 227) ng/ml, respectively. The difference in biliary CEA between group B and group C was statistically significant (P < 0.01).

CONCLUSION

CEA level in the bile collected by duodenal drainage helps confirm liver metastasis in patients with colorectal cancer.

Malaria prophylaxis using azithromycin: a double-blind, placebo-controlled trial in Irian Jaya, Indonesia

New drugs are needed for preventing drug-resistant Plasmodium falciparum malaria. The prophylactic efficacy of azithromycin against P. falciparum in malaria-immune Kenyans was 83%. We conducted a double-blind, placebo-controlled trial to determine the prophylactic efficacy of azithromycin against multidrug-resistant P. falciparum malaria and chloroquine-resistant Plasmodium vivax malaria in Indonesian adults with limited immunity. After radical cure therapy, 300 randomized subjects received azithromycin (148 subjects, 750-mg loading dose followed by 250 mg/d), placebo (77), or doxycycline (75, 100 mg/d). The end point was slide-proven parasitemia. There were 58 P. falciparum and 29 P. vivax prophylaxis failures over 20 weeks. Using incidence rates, the protective efficacy of azithromycin relative to placebo was 71.6% (95% confidence interval [CI], 50.3-83.8) against P. falciparum malaria and 98.9% (95% CI, 93.1-99.9) against P. vivax malaria. Corresponding figures for doxycycline were 96.3% (95% CI, 85.4-99.6) and 98% (95% CI, 88.0-99.9), respectively. Daily azithromycin offered excellent protection against P. vivax malaria but modest protection against P. falciparum malaria.

Mechanosensitive tyrosine phosphorylation of paxillin and focal adhesion kinase in tracheal smooth muscle

We investigated the role of the integrin-associated proteins focal adhesion kinase (FAK) and paxillin as mediators of mechanosensitive signal transduction in tracheal smooth muscle. In muscle strips contracted isometrically with ACh, we observed higher levels of tyrosine phosphorylation of FAK and paxillin at the optimal muscle length (Lo) than at shorter muscle lengths of 0.5 or 0.75 Lo. Paxillin phosphorylation was also length sensitive in muscles activated by K+ depolarization and adjusted rapidly to changes in muscle length imposed after contractile activation by either ACh or K+ depolarization. Ca2+ depletion did not affect the length sensitivity of paxillin and FAK phosphorylation in muscles activated with ACh, indicating that the mechanotransduction process can be mediated by a Ca2+-independent pathway. Since Ca2+-depleted muscles do not generate significant active tension, this suggests that the mechanotransduction mechanism is sensitive to muscle length rather than tension. We conclude that FAK and paxillin participate in an integrin-mediated mechanotransduction process in tracheal smooth muscle. We propose that this pathway may initiate alterations in smooth muscle cell structure and contractility via the remodeling of actin filaments and/or via the mechanosensitive regulation of signaling molecules involved in contractile protein activation.

Cleavage of DFF-45/ICAD by multiple caspases is essential for its function during apoptosis

Apoptosis involves the proteolysis of specific cellular proteins by a group of cysteine proteases known as caspases. Many of these cellular targets are either functionally inactivated (e.g. poly(ADP-ribose) polymerase) or activated (e.g. other caspases, gelsolin) by such processing, thereby facilitating the cell death process. Caspase 3 is involved in the processing of many of these proteins. Recently, however, it was reported that caspase 3 is dispensable for the cleavage of a large number of cellular caspase substrates during apoptosis. Among these substrates is DFF-45/ICAD, a subunit of the heterodimeric DNA fragmentation factor (DFF), otherwise known as caspase-activated DNase (CAD), that mediates genomic DNA degradation during apoptosis. Conversely, others have reported that caspase 3 is essential for the cleavage and activation of DFF-45/ICAD. To resolve this controversy we examined DFF-45/ICAD processing during apoptosis in MCF-7 breast carcinoma cells that lack functional caspase 3 and in MCF-7 cells expressing caspase 3. We found that DFF-45/ICAD is cleaved by two distinct caspases, one of which is caspase 3. Furthermore, cleavage of the carboxyl-terminal region of DFF-45/ICAD, which is necessary for activation of the enzyme, requires functional caspase 3. In the absence of caspase 3 cleavage of the amino-terminal region of DFF-45/ICAD by another caspase occurs, but the DFF-45 enzyme remains inactive.

Detection of gsp oncogene in growth hormone-secreting pituitary adenomas and the study of clinical characteristics of acromegalic patients with gsp-positive pituitary tumors

OBJECTIVE

To investigate the incidence and clinical characteristics of gsp oncogene positive growth hormone-secreting adenomas of Chinese acromegalic patients.

METHODS

Continuously 40 patients were studied. Serum hormone levels of pituitary and target glands were measured and growth hormone (GH)-TRH stimulating tests were done before transsphenoidal or transfrontal hypophysectomy. Deoxyribonucleic acid (DNA) was extracted from the frozen tumor tissue, and the DNA fragment encompassing codon 201 and 227 of the Gs alpha gene was amplified by polymerase chain reaction (PCR). Point mutations at codon 201 and 227 were detected using PCR direct sequencing method in order to get the incidence of gsp oncogene in GH secreting adenomas.

RESULTS

Of 40 tumors studied, 22 (55%) were gsp positive. The point mutation from CGT (Arg) to TGT (Cys) at codon 201 was detected in 21 pituitary tumors, but the point mutation from CAG (Gln) to CTG (Leu) at codon 227 of the Gs alpha gene was found in only 1 tumor. All of the point mutations are heterozygous. The number of gsp positive patients which have 30% or more decrease of serum GH concentration after glucose inhibition is less than that of gsp negative patients (P = 0.042). Compared to gsp negative patients, most of gsp positive patients showed paradoxical response to TRH stimulation (P = 0.002). There were more gsp positive patients with the tumor diameter less than 25 mm (P = 0.029) and with normal GH levels in OGTT after surgery (P = 0.007).

CONCLUSIONS

Gsp mutation is one of the major intrinsic defects in the pathogenesis of growth hormone-secreting pituitary tumors and the identification of gsp mutation can be a reference for classification and prognosis of GH tumors.

A statistical paradigm for neural spike train decoding applied to position prediction from ensemble firing patterns of rat hippocampal place cells

The problem of predicting the position of a freely foraging rat based on the ensemble firing patterns of place cells recorded from the CA1 region of its hippocampus is used to develop a two-stage statistical paradigm for neural spike train decoding. In the first, or encoding stage, place cell spiking activity is modeled as an inhomogeneous Poisson process whose instantaneous rate is a function of the animal's position in space and phase of its theta rhythm. The animal's path is modeled as a Gaussian random walk. In the second, or decoding stage, a Bayesian statistical paradigm is used to derive a nonlinear recursive causal filter algorithm for predicting the position of the animal from the place cell ensemble firing patterns. The algebra of the decoding algorithm defines an explicit map of the discrete spike trains into the position prediction. The confidence regions for the position predictions quantify spike train information in terms of the most probable locations of the animal given the ensemble firing pattern. Under our inhomogeneous Poisson model position was a three to five times stronger modulator of the place cell spiking activity than theta phase in an open circular environment. For animal 1 (2) the median decoding error based on 34 (33) place cells recorded during 10 min of foraging was 8.0 (7.7) cm. Our statistical paradigm provides a reliable approach for quantifying the spatial information in the ensemble place cell firing patterns and defines a generally applicable framework for studying information encoding in neural systems.

[The measurement of baroreflex sensitivity in stress-induced hypertensive rats by spectral analysis]

Simultaneous spectral analysis of short-term systolic blood pressure variability (SBPV) and heart rate variability (HRV) was applied to determine the change of baroreflex sensitivity (BRS) in Sprague-Dawley (SD) rats. The modulus of the transfer function between fluctuations in systolic pressure and beat-to-beat interval would be an appropriate quantification of BRS. The animal experiment was performed on two groups of rats: normotensive rats and stress-induced hypertensive rats (SIHR). V1-receptor antagonist d(CH2)5Tye(Me) AVP of arginine vasopressin (AVP) was microinjected into intracerebroventricle. The results showed that, in base-line condition before administration, although the BRS in very low frequency band (0-0.035 Cycle/Beat, VLF), low frequency band (0.035-0.12 Cycle/Beat, LF), high frequency band (0.12-0.32 Cycle/Beat, HF) and total BRS(the sum of the three bands) were all decreased, the BRS in VLF(P < 0.05) and LF(P < 0.01) decreased significantly by statistics; and that, to the SIHR, the BRS in VLF was significantly lower after AVP-V1 administration than in base-line condition, while to normotensive rats, the BRS did not change. It indicates that the facilitating effect of AVP on the beroreflex in SIHR is mainly due to V1-receptor in central nerve system. In summary, the transfer function between SBPV and beat-to-beat interval fluctuation could be an index of BRS. This method can be developed for future clinical application.

The granulin/epithelin precursor abrogates the requirement for the insulin-like growth factor 1 receptor for growth in vitro

3T3 cells null for the type 1 insulin-like growth factor receptor are refractory to stimulation by a variety of purified growth factors that are known to be required for the stimulation of other 3T3 cells. However, these cells, known as R- cells, grow in serum-supplemented medium and also in media conditioned by certain cell lines. We report here the purification of a growth factor that stimulates DNA synthesis (and growth) of R- cells. The growth factor, purified to homogeneity by SDS-polyacrylamide gel electrophoresis, was identified as the granulin/epithelin precursor by an accurate determination of the masses of endoproteinase Lys-C peptides using matrix-assisted laser desorption ionization mass spectrometry, followed by a data base search. The granulin/epithelin precursor is a little known growth factor, secreted by a variety of epithelial and hemopoietic cells. It is at present the only purified growth factor that can stimulate the growth of mouse embryo fibroblasts null for the type 1 insulin-like growth factor receptor.

In vivo radioprotective effects of angiogenic growth factors on the small bowel of C3H mice

This study was undertaken to determine if acidic or basic fibroblast growth factor (FGF1 or FGF2) or vascular endothelial growth factor (VEGF) alters the radiation response of small bowel after total-body irradiation (TBI). Female C3H mice were treated with various doses of angiogenic growth factor administered intravenously 24 h before or 1 h after TBI. Radiation doses ranged from 7 to 18 Gy. End points measured were the number of crypts in three portions of the small bowel, the frequency of apoptosis of crypt cells at various times after TBI, and the LD50/30 (bone marrow syndrome) and LD50/6 (GI syndrome). Fibroblast growth factors alone, without TBI, decreased the number of crypts per circumference significantly. Among the factors tested, FGF2 caused the greatest decline in baseline crypt number. Despite this decrease in the baseline crypt number, after irradiation the number of surviving crypts was greater in animals treated with growth factor. The greatest radioprotection occurred at intermediate doses of growth factor (6 to 18 pg/mouse). Mice treated with FGF1 and FGF2 had crypt survival curves with a slope that was more shallow than that for saline-treated animals, indicating radiation resistance of crypt stem cells in FGF-treated mice. The LD50/6 was increased by approximately 10% for all treatments with angiogenic growth factors, whether given before or after TBI. Apoptosis of crypt cells was maximum at 4 to 8 h after TBI. The cumulative apoptosis was decreased significantly in animals treated with angiogenic growth factors, and the greatest protection against apoptosis was seen in animals treated with FGF2 prior to TBI. All three angiogenic growth factors tested were radioprotective in small bowel whether given 24 h before or 1 h after irradiation. The mechanism of protection is unlikely to involve proliferation of crypt stem cells, but probably does involve prevention of radiation-induced apoptosis or enhanced repair of DNA damage of crypt cells.

Temperature induced structural changes of beta-crystallin and sphingomyelin binding

The study of the binding of alpha-crystallin to membranes is potentially important for understanding the function of alpha-crystallin in the ocular lens and the formation of cataracts. Using fluorescence probes, N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3 -phosphoethanolamine, triethylammonium salt (NBD-PE) and (1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid, dipotassium salt (bis-ANS), the temperature dependence of the binding of alpha-crystallin to sphingomyelin liposomes, and the structural changes of alpha-crystallin and sphingomyelin induced by temperature were studied. The influence of the binding of alpha-crystallin on the mobility of the head group region of liposomes of sphingomyelin was dependent on the thermal history of alpha-crystallin. Binding of alpha-crystallin to sphingomyelin caused a decrease in the anisotropy of the fluorophore NBD-PE at or below 37 degrees C. However, when alpha-crystallin or the mixture of alpha-crystallin/sphingomyelin were preincubated near the secondary structure phase transition temperature of 60 degrees C, an increase of the anisotropy of NBD-PE (decrease of lipid head group mobility) was observed when measured at 22 degrees C or 37 degrees C. An inflection near 47 degrees C in the curve of fluorescence anisotropy of bis-ANS pre-incorporated into the alpha-crystallin corresponded to a 3 degrees or 4 degrees structural change of alpha-crystallin. alpha-Crystallin either increases or decreases the flexibility of the head group of sphingomyelin liposomes depending on its structure.

Phosphorylation of PITSLRE p110 isoforms accompanies their processing by caspases during Fas-mediated cell death

A number of cellular proteins have been identified as caspase targets during cell death, including the PITSLRE protein kinases. These targets generally fall into one of three possible categories: 1) other caspases, 2) proteins that are inactivated during apoptosis, and 3) proteins that are required for execution of the cell death program. However, not all proteins are cleaved by caspases during apoptosis. Why only specific proteins are destined to be processed by caspases during cell death is currently not clear. Here we show that multiple caspase-like activities are involved in the processing of the PITSLRE p110 isoforms during Fas-induced apoptosis in Jurkat T-cells. Three p110 caspase cleavage sites have been mapped to the amino-terminal domain of p110 and verified by site-directed mutagenesis. Curiously, the mutagenesis studies revealed that cleavage of two juxtaposed caspase sites is necessary for the complete processing of this protein during cell death in vivo. Finally, we demonstrate that the PITSLRE p110 protein is rapidly phosphorylated during Fas-induced apoptosis in Jurkat cells and that phosphorylation of an amino-terminal portion of the protein may enhance caspase cleavage in this region.

Lipid interactions with human antiphospholipid antibody, beta 2-glycoprotein 1, and normal human IgG using the fluorescent probes NBD-PE and DPH

Recurrent venous thrombosis, arterial thrombosis and pregnancy losses are clinical manifestation associated with antiphospholipid antibody (aPL) that recognizes negatively charged phospholipid antigens. Enzyme-linked immunosorbent assays (ELISA) are generally used to determine the presence and specificity of aPL. In this paper, a fluorescence spectroscopy method has been applied, through monitoring the alteration of fluorescence intensity and anisotropy of a fluorophore that was incorporated in liposomes to explore the changes of molecular structure or configuration elicited by the binding aPL with phospholipid antigens. The bilayer surface was markedly ordered by aPL binding as indicated by the surface-sensitive probe NBD-PE. The binding of aPL on the bilayer surface is saturable. The saturation concentration of aPL is 40% (w/w, aPL/lipid) for cardiolipin membranes. The binding of aPL on cardiolipin took place in the absence of beta 2-GP1. The addition of beta 2-GP1 further increased the anisotropy and decreased the intensity of fluorescence. The binding of aPL is predominantly attributed to electrostatic interaction, but the configuration of the acyl chains of phospholipid also plays a role. It is found that the thermal history is important for aPL binding. The incubation at 37 degrees C is more favorable for aPL binding than ambient temperature. Normal human serine (IgG-NHS) did not elicit any distinct change of NBD-PE fluorescence, which indicates it does not interact with the lipid.

The molecular basis of viral oncolysis: usurpation of the Ras signaling pathway by reovirus

NIH-3T3 cells, which are resistant to reovirus infection, became susceptible when transformed with activated Sos or Ras. Restriction of reovirus proliferation in untransformed NIH-3T3 cells was not at the level of viral gene transcription, but rather at the level of viral protein synthesis. An analysis of cell lysates revealed that a 65 kDa protein was phosphorylated in untransformed NIH-3T3 cells, but only after infection with reovirus. This protein was not phosphorylated in infected or uninfected transformed cells. The 65 kDa protein was determined to be the double-stranded RNA-activated protein kinase (PKR), whose phosphorylation leads to translation inhibition. Inhibition of PKR phosphorylation by 2-aminopurine, or deletion of the Pkr gene, led to drastic enhancement of reovirus protein synthesis in untransformed cells. The emerging picture is one in which early viral transcripts trigger PKR phosphorylation in untransformed cells, which in turn leads to inhibition of translation of viral genes; this phosphorylation event is blocked by an element(s) in the Ras pathway in the transformed cells, allowing viral protein synthesis to ensue. The usurpation of the Ras signaling pathway therefore constitutes the basis of reovirus oncolysis.

Pancreatic adenocarcinomas with DNA replication errors (RER+) are associated with wild-type K-ras and characteristic histopathology. Poor differentiation, a syncytial growth pattern, and pushing borders suggest RER+

The clinical and pathological features of carcinomas of the pancreas with DNA replication errors (RER+) have not been characterized. Eighty-two xenografted carcinomas of the pancreas were screened for DNA replication errors using polymerase chain reaction amplification of microsatellite markers. Cases with microsatellite instability in at least two markers of a minimum of five tested were considered RER+. RER status was correlated with histological appearance, karyotype of the carcinomas when available, K-ras mutational status, and patient outcome. Three (3.7%) of the eighty-two carcinomas were RER+. In contrast to typical gland-forming adenocarcinomas of the pancreas, all three RER+ carcinomas were poorly differentiated and had expanding borders and a prominent syncytial growth pattern. Neither a Crohn's-like lymphoid infiltrate nor extracellular mucin production were prominent. Ductal adenocarcinomas of the pancreas typically contain a mutant K-ras gene, yet all three RER+ carcinomas had wild-type K-ras. One of the three RER+ carcinomas was karyotyped and showed a near diploid pattern. All three of the RER+ tumors were removed via Whipple resection. One of the three patients is free of disease 16 months after pancreaticoduodenectomy, one is alive and free of tumor at 52 months but developed two colon carcinomas during this period, and the third died of pancreatic cancer at 4 months. None of the three patients had a family history of colorectal carcinoma. A review of the K-ras wild-type carcinomas in a previously characterized series of pancreatic carcinomas with known K-ras mutational status identified two additional cancers with poor differentiation, a syncytial growth pattern, and pushing borders. Both of the cancers were diploid and both patients were longterm survivors (over 5 years). The inclusion of such patients in previous prognostic studies of pancreas cancer may explain the failure of histological grade to be a predictor of prognosis. These data suggest that DNA replication errors occur in a small percentage of resected carcinomas of the pancreas and that wild-type K-ras gene status and a medullary phenotype characterized by poor differentiation, and expanding pattern of invasion, and syncytial growth should suggest the possibility of DNA replication errors in carcinomas of the pancreas.

Influence of cholesterol on the interaction of alpha-crystallin with phospholipids

The influence of cholesterol on the binding of alpha-crystallin to pure phospholipid membranes was studied. The rationale of this investigation stems from two unique aspects of human lens cells: an unusually high level of cholesterol in the membranes and the specific binding of alpha-crystallin to membranes. In the absence of cholesterol, binding of alpha-crystallin liposomes composed of either sphingomyelin, disteroyl-phosphatidylcholine or egg-phosphatidylcholine caused a decrease in the fluorescence intensity and anisotropy of the fluorophore NBD-PE. Since this fluorescence probe resides in the polar headgroup region of the membrane, the observed changes indicated that the binding of alpha-crystallin affected the structure of these membrane regions. The ability of alpha-crystallin to modulate membrane structure suggests yet another potential role for this lens protein. Addition of cholesterol markedly decreased the binding of alpha-crystallin to liposomes composed of either sphingomyelin or disteroylphosphatidylcholine and antagonized the capacity of bound alpha-crystallin to decrease membrane surface order. This antagonism could be explained by the ability of cholesterol to directly decrease the anisotropy of the fluorophore in sphingomyelin membranes unexposed to alpha-crystallin. Thus, with cholesterol present, a further decrease in membrane order upon subsequent binding of alpha-crystallin was less likely. The results obtained with the sphingomyelin liposomes are considered most meaningful, since sphingomyelins are the principal phospholipids in the human lens nuclear membrane and cholesterol preferentially interacts with sphingomyelin. We conclude that cholesterol in lipid membranes can antagonize the binding of alpha-crystallin and thus interfere with the capacity of bound alpha-crystallin to alter membrane order. We suggest that such actions of cholesterol might serve to preserve lens membrane structure in the physiological state where the concentration of soluble alpha-crystallin is great.

[Glucose-6-phosphate dehydrogenase mutations among Cantonese revealed by polymerase chain reaction using dried blood spots]

OBJECTIVE

To analyze G6PD gene mutation in 168 Cantonese G6PD deficient male infants.

METHODS

PCR products were amplified directly from dried blood spots on filter paper using 7 pairs of special primers followed by digestion with a restriction enzyme.

RESULTS

Of the 168 samples, 72(42.8%) were G6PD 1376 G-->T mutation, 35 (20.8%) were G6PD 1388 G-->A, 30(17.9%) were G6PD 95 AG, 6(3.6%) were G6PD 392 G-->T, and 3(1.8%) were G6PD 1024 C-->T. No G6PD 493 A-->G and 487 G-->A mutation were found, and 22(13.1%) were not defined.

CONCLUSION

1. The three G6PD mutations at 1376, 1388 and 95 were common in Cantonese. 2. Dried blood spots collected on filter paper provide an easy way of sample collection, storage and transport for the epidemiological study of inherited disease.

Successful cure of an extensive burn injury complicated with mucor wound sepsis

Mucormycosis is an opportunistic infection occurring in the severely immunocompromised patient. A case of mucormycosis occurring in a patient who sustained an 85 per cent TBSA burn injury is reported. Diagnosis and management is reported in the paper.

The intermediate filament protein peripherin is a marker for cerebellar climbing fibres

Immunocytochemical staining with antibodies to the class III intermediate filament protein peripherin reveals discrete subpopulations of neurons and nerve fibres throughout the rat central nervous system. Some of these fibres enter the cerebellar granular and molecular layers. Here we use light and electron microscopic immunocytochemistry and confocal fluorescence microscopy to identify the peripherin positive fibres in the molecular layer of the cerebella of various mammals. (1) The peripherin positive fibres in the molecular layer have morphological attributes of climbing fibres, and peripherin positive fibres are also detected in the olivo-cerebellar tract. Furthermore peripherin positive neurons can be seen in the inferior olive, from which climbing fibres originate. (2) The peripherin positive molecular layer fibres rapidly degenerate in rats treated with 3-acetylpyridine (3-AP), a reagent which destroys neurons in the inferior olive, and the time course of degeneration of these mirrors that previously described for 3-AP induced destruction of climbing fibres. (3) Cerebella of other mammal species tested (mouse, rabbit, pig, cow and human) revealed a similar peripherin staining pattern in the cerebellum, including fibres in the molecular layer with the morphology of climbing fibres. (4) We also noted peripherin positive spinocerebellar and vestibulocerebellar mossy fibres in the cerebellar granular layer of folia known to receive these inputs. (5) A subset of perivascular nerve fibres are also peripherin positive. These results show that peripherin is a useful marker for mammalian cerebellar climbing fibres, and that a subset of morphologically distinct cerebellar mossy fibres are also peripherin positive.

Association of neurofilament proteins with neuronal Cdk5 activator

Cdk5 exists in brain extracts in multiple forms, one of which is a macromolecular protein complex comprising Cdk5, neuron-specific Cdk5 activator p35nck5a and other protein components (Lee, K.-Y., Rosales, J. L., Tang, D., and Wang, J.H. (1996) J. Biol. Chem. 271, 1538-1543). The yeast two-hybrid system was employed to identify p35nck5a-interacting proteins from a human brain cDNA library. One of the isolated clones encodes a fragment of glial fibrillary acidic protein, which is a glial-specific protein. Sequence alignment revealed significant homology between the p35nck5a-binding fragment of glial fibrillary acidic protein and corresponding regions in neurofilaments. The association between p35nck5a and neurofilament medium molecular weight subunit (NF-M) was confirmed by both the yeast two-hybrid assay and direct binding of the bacteria-expressed proteins. The p35nck5a binding site on NF-M was mapped to a carboxyl-terminal region of the rod domain, in close proximity to the putative Cdk5 phosphorylation sites in NF-M. A region immediately amino-terminal to the kinase-activating domain in p35nck5a is required for its binding with NF-M. In in vitro binding assays, NF-M binds both monomeric p35nck5a and the Cdk5/p35nck5a complex. The binding of NF-M has no effect on the kinase activity of Cdk5/p35nck5a.

Expression of functional domain of chicken gizzard calponin

A full-length cDNA of the function domain of wild-type chicken gizzard calponin was cloned into expression vector pAED4 and the recombinant function domain of wild-type calponin was expressed in an Escherichia coli expression system. The actin domain of calponin (CaP-B) can bind with actin and it is a requisite for its inhibition of ATPase and vasoconstriction of smooth muscle. In this study, the cDNA of CaP-B was inserted into vector pAED4 by direction-cloning method. The cDNA of CaP-B was obtained with PCR cloning technique. The recombinant DNA pAED4-Cap-B was transformed into E. coli BL21 (DE3) and identified with the restriction analysis. The bacterial clones containing transformants were induced to be highly expressed in E. coli BL21 (DE3). The target protein was detected and identified by Western Blot analysis. The content of target protein was as high as 10% of the whole protein after overnight (16 h) culture. The results confirmed that Cap-B was relatively highly expressed in E. coli.

[Determination of vincristini sulfas in tumor cells by high performance liquid chromatography]

Vincristini sulfas (VCR) is an important common antitumor drug. The resistance to anticancer drug is the main cause of the chemotherapy failure. To screen the drugs which can reverse VCR resistance for VCR resistant cell strain, an analytical method has been established for the determination of VCR concentration in tumor cells using high performance liquid chromatography (HPLC). The stainless steel column was 25 cm x 4.6 mm i.d. packed with totally porous, spherical silica particles (5 microns). A solution of methanol and 0.02 mol/L dipotassium hydrogen phosphate (80:20, V/V) adjusted to pH 6.6 with H3PO4 was employed as the mobile phase. The flow rate was 1 mL/min. Chromatography was performed with ultraviolet detector at 267 nm. The method is simple, rapid and selective. Linear calibration curve for VCR was measured within the range of 10 to 200 mg/L with correlation coefficient of 0.999 8. The lowest detection limit was 4 mg/L tumor cells extract. The HPLC method described is suitable for clinical monitoring and pharmacokinetic study of VGR.

Induction of the cholesterol metabolic pathway regulates the farnesylation of RAS in embryonic chick heart cells: a new role for ras in regulating the expression of muscarinic receptors and G proteins

We propose a novel mechanism for the regulation of the processing of Ras and demonstrate a new function for Ras in regulating the expression of cardiac autonomic receptors and their associated G proteins. We have demonstrated previously that induction of endogenous cholesterol synthesis in cultured cardiac myocytes resulted in a coordinated increase in expression of muscarinic receptors, the G protein alpha-subunit, G-alphai2, and the inward rectifying K+ channel, GIRK1. These changes in gene expression were associated with a marked increase in the response of heart cells to parasympathetic stimulation. In this study, we demonstrate that the induction of the cholesterol metabolic pathway regulates Ras processing and that Ras regulates expression of G-alphai2. We show that in primary cultured myocytes most of the RAS is localized to the cytoplasm in an unfarnesylated form. Induction of the cholesterol metabolic pathway results in increased farnesylation and membrane association of RAS. Studies of Ras mutants expressed in cultured heart cells demonstrate that activation of Ras by induction of the cholesterol metabolic pathway results in increased expression of G-alphai2 mRNA. Hence farnesylation of Ras is a regulatable process that plays a novel role in the control of second messenger pathways.

[The expression of calponin in Oddi's sphincters and its actions during gallstone formation]

OBJECTIVES

To study on the expression of calponin in an animal model of gallstone disease and investigate the molecular mechanisms of gallstone formation.

METHODS

After feeding a high-cholesterol diet to guinea pigs, Oddi's sphincters were disseced on day 30 and day 60 respectively. We used RT-PCR, western-blotting to evaluate expression level of calponin gene.

RESULTS

Down-regulation of calponin gene expression was observed in animals with gallstone. The levels of both protein and mRNA expression for calponin on day 30 and day 60 were lower than those of control group with the level from day 60 lower than that from day 60, while myosin expressions were relatively stable.

CONCLUSION

Our results indicated that the decrease of calponin could increase the pressure of sphincter of Oddi, aggravate the stasis of bile and promote the gallstone formation.

[The effect of recombinant human growth hormone on thyroid function in patients with growth hormone deficiency]

To evaluate the effect of growth hormone treatment on thyroid function of growth hormone deficient children, 19 (18M/1F) euthyroid children of growth hormone deficiency (GHD) were treated with Genotropin, a recombinant human growth hormone (rhGH) for 12 months. rhGH was injected subcutaneously with a daily dosage of 0.1 IU/kg. All the patients were diagnosed by two GH provocative stimulating tests with the serum GH peak level < 7 micrograms/L. During the treatment, blood was drawn before or 6 and 12 months after the initiation of therapy to measure serum T3, T4, FT3, FT4, rT3 and thyroid-stimulating hormone (TSH) levels. In the meantime, thyrotropin releasing hormone (TRH) stimulating test was performed by an i.v. injection of 200 micrograms synthetic TRH. The results showed that (1) the average serum levels of T4 and FT4 decreased significantly 6 at the 6th and 12th month (P < 0.001), while the serum FT3 level decreased only at the 6th month (P < 0.05). The serum T3, rT3 and TSH concentrations remained unchanged. (2) 8 euthyroid patients (45%) became subclinical hypothyroidism after 12 months' treatment with rhGH for their serum FT4 levels fell to below the normal range. The 19 patients were divided into thyroid function normal (n = 11) and subnormal group (n = 8) according to their posttreatment thyroid functions. (3) The TSH response to TRH was evaluated by the area under the curve (AUC) of serum TSH. The average AUC was greater in the subnormal group than in the normal group whether before or 6 and 12 months after the treatment. The greater TSH response to TRH among patients with decreased posttreatmental FT4 levels suggests that latent TRH deficiency has already existed, which may be the pathogenetic basis of the hypothyroidism developped after rhGH treatment. Thus the thyroid function of GHD patients should be monitored during rhGH treatment in order that the thyroxine replacement therapy can be given in time.

Characterization of additional casein kinase I sites in the C-terminal "tail" region of chicken and rat neurofilament-M

In previous studies we have identified Ser502, Ser528, and Ser534 as target sites in chicken neurofilament middle molecular mass protein (NF-M) for casein kinase I (CKI) in vitro and have shown that these sites are also phosphorylated in vivo. We now make use of a combination of molecular biological and protein chemical techniques to show that two additional in vivo phosphorylation sites in chicken NF-M, Ser464 and Ser471, can also be phosphorylated by CKI in vitro. These two sites are conserved in higher vertebrate NF-M molecules, and recombinant protein constructs containing the homologous rat NF-M peptides can be phosphorylated by CKI in vitro, suggesting that phosphorylation of these sites is conserved at least in higher vertebrates. The two new sites are adjacent to a conserved peptide sequence (VEEIIEET-V) found once in higher vertebrate NF-M molecules and twice in lamprey NF-180. Variants of this sequence are also found in neurofilament low and high molecular mass proteins (NF-L and NF-H) and alpha-internexin, and in mammalian NF-L are known to be associated with in vivo phosphorylation sites. We speculate that CKI phosphorylation in general, and these sites in particular, may be important in neurofilament function.

Variability in PAH-DNA adduct measurements in peripheral mononuclear cells: implications for quantitative cancer risk assessment

Biomarkers such as DNA adducts have significant potential to improve quantitative risk assessment by characterizing individual differences in metabolism of genotoxins and DNA repair and accounting for some of the factors that could affect interindividual variation in cancer risk. Inherent uncertainty in laboratory measurements and within-person variability of DNA adduct levels over time are putatively unrelated to cancer risk and should be subtracted from observed variation to better estimate interindividual variability of response to carcinogen exposure. A total of 41 volunteers, both smokers and nonsmokers, were asked to provide a peripheral blood sample every 3 weeks for several months in order to specifically assess intraindividual variability of polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels. The intraindividual variance in PAH-DNA adduct levels, together with measurement uncertainty (laboratory variability and unaccounted for differences in exposure), constituted roughly 30% of the overall variance. An estimated 70% of the total variance was contributed by interindividual variability and is probably representative of the true biologic variability of response to carcinogenic exposure in lymphocytes. The estimated interindividual variability in DNA damage after subtracting intraindividual variability and measurement uncertainty was 24-fold. Inter-individual variance was higher (52-fold) in persons who constitutively lack the Glutathione S-Transferase M1 (GSTM1) gene which is important in the detoxification pathway of PAH. Risk assessment models that do not consider the variability of susceptibility to DNA damage following carcinogen exposure may underestimate risks to the general population, especially for those people who are most vulnerable.

[A follow-up survey of results of lacrimal gland surgery of pleomorphic adenoma]

OBJECTIVE

To investigate the causes of recurrence and malignant change of pleomorphic adenoma (benign mixed tumour) of lacrimal gland.

METHODS

42 cases with the adenoma were followed postoperatively, the follow-up periods ranging from 0.5 to 17.0 years.

RESULTS

In the follow-up, 34 cases had no recurrence or malignant change, and 8 cases had recurrences. Of the cases with recurrences, 7 cases had undergone several times of surgeries, because of incomplete resection of the tumor leading to recurrence.

CONCLUSION

The key points to obtain success of the surgery and to decrease the rate of recurrence are complete removal of the tumor in its capsule in the initial surgery, and avoidance of aspiration or biopsy made before the operation.

[Seasonal variation on reproductive cycle of the female Chinemys reevesii]

Seasonal variation in the reproductive cycle of female Chinese three-keeled pond turtles, Chinemys reevesii, was studied. Vitellogenesis began in early October and reached maximum level in early May (maximum follicle diameter was 19.2 mm). The first clutch was laid in June. Oviposition continued until August when follicular regression began. An ovarian quiescent period was evident in September. Two-three clutches are laid per year. Mean clutch size is 5. Annual reproductive potential ranges from 10 to 15 eggs. Age at maturity for females is six years.

Changes in the expression of novel Cdk5 activator messenger RNA (p39nck5ai mRNA) during rat brain development

We previously reported that a neuron-specific Cdk5 activator, p35nck5ai, was most prominent in the newborn rat brain. In the adult brain, the expression decreased in most regions except hippocampus and primary olfactory cortex. A novel neuron-specific Cdk5 activator, p39nck5ai, has been recently cloned. To clarify whether two activators were differentially distributed throughout brain development, in this study, we examined the spatial and temporal expression of p39nck5ai in the development rat brain. Northern blot analysis showed that p39nck5ai expression was low in 15-day old fetuses and newborn, and was most prominent in the 1-3 week-old rat brains. In the adult rat brain, expression declined to the same level as in newborn rat brain. In situ hybridization showed that p39nck5ai mRNA was weakly expressed in all neurons of all regions in the newborn rat brain and the transcriptional level was highest in all regions in the 3 week-old rat brain. In the adult, expression was decreased in most neurons except Purkinje and granule cells in the cerebellum which retained high levels. These results suggest that p35nck5a and p39nck5ai may have different functional roles in distinct brain regions during different states of the rat brain development.

Microbiologic and clinical value of primary broth cultures of wound specimens collected with swabs

In order to assess the microbiologic and clinical value of primary broth culture of wound specimens collected with swabs and submitted to the laboratory in transport medium, we compared the results of primary agar culture with the results of a corresponding primary broth culture for 344 aerobic specimens and 176 anaerobic specimens. While 8.7% (45 of 520) of the specimens yielded organisms from the primary broth culture that were not recovered from the corresponding primary agar culture, only 5.0% (26 of 520) of the specimens yielded organisms from the primary broth culture other than Staphylococcus epidermidis, viridans group streptococci, and Corynebacterium spp. Moreover, the primary broth culture of only 0.6% (3 of 520) of the specimens yielded organisms not recovered from the primary agar culture that caused a change in the therapy of the patient. Our conclusion is that primary broth cultures are unnecessary for the processing of wound specimens properly collected with swabs.