Paget's disease of the tibia

Paget's disease of the bone is perceived to be rare in Asia. We report the first documented case of Paget's disease of the bones in Taiwan. A 66-year-old native Taiwanese woman was admitted to hospital with a 10-year history of pain and a bowing deformity of her left leg. Laboratory data disclosed elevated serum calcium and alkaline phosphatase levels, but no leukocytosis. A plain X-ray film of the left leg showed a curved tibia with thickening of the tibial cortex, while a technetium 99m bone scan revealed abnormal uptake in the left tibia. Elevated serum levels of bone-specific alkaline phosphatase and urinary collagen N-telopeptide were also noted. Histologic examination of a biopsy specimen of the left tibia lesion confirmed the diagnosis of Paget's disease in the bone. The patient received treatment with sodium chlodronate, and the symptoms improved rapidly. Laboratory data then revealed decreased levels of serum calcium, bone-specific alkaline phosphatase, and urinary collagen N-telopeptide after treatment.

High-resolution ultrasonography in detection and follow-up of a tumour of the forearm. Case report

A 39-year-old man had a mass in his right flexor medial mid-forearm of unknown aetiology for two years. Preoperative high-resolution ultrasonography showed a well-defined solid mass with reduced echogenicity. The mass was excised and histopathological examination showed neurilemmoma. There had been no recurrence of the tumour six months after operation.

Mechanical properties of heel pads reconstructed with flaps

We compared the mechanical properties of normal and reconstructed heel pads in seven patients. Four had latissimus dorsi flaps and one each an anterior thigh flap, a local dorsalis pedis flap and a sural arterial flap. The thickness of the heel pad was measured under serial incremental loads of 0.5 kg to a maximum of 3 kg and then relaxed sequentially. The load-displacement curve of the heel pad during a loading-unloading cycle was plotted and from this the unloaded heel-pad thickness (UHPT), compressibility index (CI), elastic modulus (Ep), and energy dissipation ratio (EDR) were calculated. The EDR was significantly increased in the reconstructed heels (53.7 +/- 18% v 23.4 +/- 6.5%, p = 0.003) indicating that in them more energy is dissipated as heat. Insufficient functional capacity in the reconstructed heel pad can lead to the development of shock-induced discomfort and ulceration.

Leukocyte adhesion deficiency disorder: report of one case

In this paper, a case of leukocyte adhesion deficiency disorder confirmed by flow cytometry and leukocyte chemotaxis assays is reported. The 32-day-old female infant was admitted to our ward on account of delayed umbilical cord detachment and omphalitis. After admission, hemogram revealed severe leukocytosis (white blood cell (WBC) counts: 86,800/cumm), and there was poor clinical response to several kinds of antibiotics. The above history indicated that the patient might be a case of leukocyte adhesion deficiency disorder. A definite absence of CD11b/CD18 adhesion molecule on the patient's granulocytes and severe defects of leukocyte function demonstrated by chemotaxis, chemokinesis and zymosan-induced respiratory burst assays confirmed this diagnosis.

Ultrasonographic assessment of posterior heel pain

To investigate the value of ultrasonography in the diagnosis of posterior heel pain, 68 patients with normal plain x-ray findings of the posterior heel underwent ultrasonographic examination with a 10-MHz linear array probe. The findings included Achilles tendinosis (31 patients), retrocalcaneal bursitis (12), superficial Achilles bursitis (7), soft tissue mass (7), Achilles tendon rupture (4), xanthoma (3), tenosynovitis of the flexor hallucis longus tendon (2), and negative findings (2). Sixteen of these patients underwent surgery after ultrasonographic examination. The surgical diagnoses were consistent with the ultrasonographic diagnoses in all cases. With high-resolution ultrasonography, pathologic conditions of the posterior heel can be readily differentiated.

Hypokalemia and salbutamol therapy in asthma

Hypokalemia is a common side effect in adult asthmatic patients on beta 2 adrenergic therapy. There is limited information in regard to hypokalemia and its relation to the clinical responses following administration of beta 2 agonist therapy in children with asthma. We observed that salbutamol inhalation significantly improved asthmatic symptoms as demonstrated by increases in peak expiratory flow (PEF: 122.37+/-75.38 vs. 152.59+/-80.29; P < 0.001) and venous oxygen tension (Pv,O2: 33.24+/-4.95 vs. 58.16+/-2.31; P < 0.001), and decreases in respiratory rate (RR: 36.39+/-3.78 vs. 28.62+/-3.12; P< 0.01), clinical scores (CS: 3.59+/-1.28 vs. 1.59+/-0.71), and venous PCO2 tensions (Pv,CO2: 40.84+/-2.67 vs. 34.75+/-2.31; P < 0.001). Salbutamol-induced hypokalemia was correlated with a decrease in RR, and an increase of Pv,O2 and PEF. These findings suggest that the same mechanism is involved in eliciting hypokalemia and bronchodilatation.

Variations in heel pad mechanical properties variation between children and young adults

The purpose of this study was to compare the mechanical properties of the heel pads of adults and children, using ultrasound to assess the responses of the heel pad during compression. Thirty volunteers without heel problems, aged from 4 to 36 years, were recruited. There were 10 children (< 15 years old) and 20 adults (> 18 years old). A 7.5-MHz linear array ultrasound transducer was incorporated into a specially designed device to measure the thickness of the heel pad under different loads. The load on the heel pad was increased serially in increments of 0.5 kg, to a maximum of 3 kg, and then reduced sequentially. The load-displacement curve of the heel pad during a loading-unloading cycle was then plotted. Mechanical properties of the heel, including unloaded heel-pad thickness (UHPT), compressibility index, elastic modulus, and energy dissipation ratio (EDR), were calculated from the load-displacement curves. The average UHPT was 1.53 +/- 0.09 cm in children and 1.76 +/- 0.20 cm in adults (p < 0.001). The EDR, which represents the shock absorbency of the heel pad, was 13.5 +/- 2.0% in the children and 23.7 +/- 6.9% in adults (p < 0.001). The average compressibility index and elastic modulus were also higher in adults than in children, although the differences were not statistically significant. These findings suggest that the mechanical properties of the heel pad change from childhood to adulthood. Less energy is absorbed in the heel pad of children, which may partially explain why children tend to have fewer heel problems than adults.

Ketosis resistance in the male offspring of protein-malnourished rat dams

Plasma beta-hydroxybutyrate concentrations were measured in the offspring of rats that were fed either a control (20% protein) diet or low-protein (8% protein) diet during pregnancy and lactation. Low-protein offspring had significantly lower plasma beta-hydroxybutyrate compared with controls in the fed state (P < .04) and after fasting for 24 hours (P < .001) and 48 hours (P < .04). There were no differences in blood glucose, acetoacetate, plasma glucagon, cholesterol, or glycerol between control and low-protein offspring. However, plasma nonesterified fatty acids (NEFAs) were significantly higher in low-protein offspring in the fed state (P < .05). In contrast, plasma triglycerides and insulin were significantly lower in low-protein offspring compared with controls when fed (P < .001) and after a 24-hour fast (P < .001). These results suggest that poor maternal and early postnatal nutrition can have long-term effects on ketone body metabolism in the offspring during adulthood. This apparent ketosis resistance is similar to that observed in some forms of human diabetes.

Comparison of the mechanical properties of the heel pad between young and elderly adults

OBJECTIVE

To compare the mechanical properties of the human heel pad between young and aged adults.

DESIGN

A 7.5-MHz linear-array ultrasound transducer was incorporated into a specially designed device to measure the thickness of the heel pad under different loads. The heel pad was compressed with serial increments of 0.5kg to a maximum of 3kg and then relaxed sequentially. Then the load-displacement curve of the heel pad during a loading-unloading cycle was plotted.

PARTICIPANTS

Convenience sample of 33 volunteers without heel problems, aged 18 to 78 years, were divided into young (less than 40 years) and elderly (older than 60 years) groups.

MAIN OUTCOME MEASURES

Unloaded heel-pad thickness, compressibility index, stiffness, and energy dissipation ratio were calculated from the load-displacement curves. Student's t-test was used to compare the mechanical properties of the heel between these two groups.

RESULTS

The average unloaded heel-pad thickness was 1.76+/-.20cm in the young group and 2.01+/-.24cm in the elderly group (p < .001). The average compressibility index was 53.3%+/-7.7% in the young group and 61.3%+/-5.5% in the elderly group (p < .001). Energy dissipation ratio representing shock absorbency of the heel pad, was 23.7%+/-6.9% in the young group and 35.3%+/-10% in the elderly group (p < .001).

CONCLUSION

Unloaded heel-pad thickness, compressibility index, and energy dissipation ratio of the heel pad were significantly increased in the elderly group, indicating loss of the elasticity of the heel pad. The loss of elasticity may be responsible for the higher incidence of heel injury in elderly individuals.

Compact and Efficient 3.2-W Diode-Pumped Nd:YVO(4)/KTP Green Laser

We demonstrate a simple way to achieve single-frequency operation by using fiber-coupled diode-pumped Nd:YVO(4)/KTP green lasers in a short standing-wave linear cavity. A single-mode output with 3.2-W green power was generated with a 12.6-W pump power corresponding to a conversion efficiency of 25.4%. The single-mode operation was obtained through the combined action of the anisotropic emission cross section of Nd:YVO(4) and the KTP crystal acting as a birefringent filter.

Effect of tetramethylpyrazine on reserpine-induced gastric lesion in rats

The present study was undertaken to determine the effect of tetramethylpyrazine administered intraperitoneally on gastric lesions, gastric acid secretion, gastric barrier mucus secretion, and gastric contraction in reserpine-treated rats. The results of this study demonstrated that tetramethylpyrazine at doses of 0.5, 1, 10, and 20 mg/kg significantly inhibited the formation of gastric lesions induced by reserpine, with suppressive rates of 57.5%, 64.0%, 94.1%, and 96.0%, respectively. Tetramethylpyrazine (1 and 20 mg/kg) significantly prompted the secretion of gastric barrier mucus but had no effect on the secretion of gastric acid. Our findings also showed that tetramethylpyrazine (1 and 20 mg/kg) significantly suppressed the frequency of gastric contractions, but had no effect on the amplitude of gastric contraction. These results indicate that the protection of tetramethylpyrazine results, in part, from promoting gastric barrier mucus secretion and suppressing the frequency of gastric contraction, but not from suppressing the secretion of gastric acid and the amplitude of gastric contraction.

Purification and characterization of four catechol 1,2-dioxygenase isozymes from the benzamide-assimilating bacterium Arthrobacter species BA-5-17

When Arthrobacter sp. BA-5-17 was grown on benzamide, the bacterium synthesized four different catechol 1,2-dioxygenase (CD, EC 1.13.11.1) isozymes (CD-I, II, III-1, and III-2). We purified each CD to homogeneity by a series of column chromatography. The molecular masses of the four CDs were between 68 and 72 kDa. The enzymes were made up of two identical subunits each with the molecular mass of 33 kDa. CD-I and II were indistinguishable in enzymatic properties tested. Most properties of CD-III-1 were similar to those of CD-III-2. However, CD-III-1 had a marked adsorption peak at 325 nm, which disappeared in CD-III-2 as well as in CD-I and II. CD-III-1 and III-2 were much more resistant to heating and inhibitors than CD-I and II.

Mode-locked diode-pumped self-frequency-doubling neodymium yttrium aluminum borate laser

As far as we know this is the first report on picosecond green-light generation from an actively mode-locked diode-pumped self-doubling neodymium yttrium aluminum borate (NYAB) laser. The pulse width is approximately 100 ps and is limited by imperfect antireflection coating and the intracavity doubling effect. The green average output power of this laser for mode-locked operation was more than 12 times higher than that for the continuous wave NYAB laser. The polarization state of the laser can be switched from ordinary to extraordinary rays by displacement of the pump spot. The polarization ratio can be better than 200 without any intracavity polarization element.

Sonographic detection of a stitch abscess

A 28-year-old man with a ruptured right Achilles tendon underwent primary end-to-end suture immediately after injury. Painful swelling developed 6 months later, and a lump with discharge from a sinus was observed during physical assessment. Sonographic examination with a 10-MHz linear-array transducer demonstrated a hypoechoic mass, 8 x 6 mm, within which were 2 markedly echogenic dots. A stitch abscess was strongly suspected and was confirmed surgically.

Ca2+ and Zn2+ bind to different sites and induce different conformational changes in human calcyclin

Calcyclin (CaCY) is a member of the S100 subfamily of helix-loop-helix (EF-hand) calcium-binding proteins. Human CaCY was overexpressed in Escherichia coli and purified with an overall yield of 40 mg/l culture. Ca2+ and Zn2+ binding properties of CaCY were examined with respect to the oxidation state of the single Cys residue at position 3. CaCY with the SH group either reduced, blocked or oxidized stays as a dimer as shown by analytical ultracentrifugation. Upon binding of Ca2+, CaCY exhibits 30% enhancement of the Tyr fluorescence, the apparent binding constant (Ka) being 2.8-5.8x10(4) M(-1). Oxidized CaCY binds Ca2+ approximately twice as weakly than its reduced form. The affinity for Ca2+ is increased in the presence of caldesmon, which could be a potential target molecule. Fully reduced CaCY binds Zn2+ with an affinity of at least 1.0x10(7) M(-1). As compared to Ca2+, Zn2+ binding results in a three times greater enhancement of the Tyr fluorescence. Saturation occurs at a Zn2+/CaCY ratio of 2:1. The reactivity of Cys3 is reduced by Zn2+ binding, although oxidized CaCY still binds Zn2+. On the basis of the effects of thiol-directed labels on the affinities for Ca2+ and Zn2+, the fluorescence changes accompanying the binding, and the CaCY reactivity with a hydrophobic probe, it was concluded that the two cations bind to CaCY at different sites: Ca2+ binds probably at the EF-hand type sites, whereas binding of at least one Zn2+ ion involves the Cys residue, and results in a different structural change.

Macrophage-colony stimulating factor (M-CSF) regulates the expression of fibronectin and its alpha5 integrin receptor in human trophoblasts

Macrophage-colony stimulating factor (M-CSF, CSF-1) is secreted by human trophoblasts as well as endometrial cells, while its receptor c-fms is abundantly expressed by the extravillous trophoblasts anchoring the placenta to the uterus, suggesting a role for M-CSF at the maternal-fetal interface. We investigated the effect of M-CSF on the expression of fibronectin and its receptor, the alpha5 integrin, in human trophoblasts. Exposure of trophoblasts to M-CSF produced a two to three-fold increase in fibronectin and alpha5 mRNA abundance at both 24 and 72 hours of culture. A dose-dependent increase in cellular fibronectin secretion into the culture medium was detected at both time points. Immunocytochemistry showed co-localization of cellular fibronectin and alpha5 in the cells, suggesting that attachment of trophoblasts to fibronectin is mediated in part by the alpha5beta1 integrin. We conclude that M-CSF increases fibronectin expression and secretion by the human trophoblasts, and up-regulates its specific receptor, the alpha5 integrin. We hypothesize that M-CSF may partake in the autocrine/paracrine mechanisms regulating trophoblast invasion during implantation.

Sonography of pigmented villonodular synovitis in the ankle joint

Pigmented villonodular synovitis is a benign proliferative disorder of the synovium that results in villous nodule formation in joints, tendon sheaths, and bursae. We present a case of pigmented villonodular synovitis of the ankle joint that was diagnosed by sonography with color Doppler imaging. The sonograms revealed hypoechoic synovial proliferation, and hypervascularity was visible on color Doppler images. The differential diagnosis of a synovial thickening or mass is also discussed.

A new two-dimensional block adaptive FIR filtering algorithm and its application to image restoration

This paper presents a new two-dimensional (2-D) optimum block stochastic gradient (TDOBSG) algorithm for 2-D adaptive finite impulse response (FIR) filtering. The TDOBSG algorithm employs a space-varying convergence factor for all the filter coefficients, where the convergence factor at each block iteration is optimized in a least squares sense that the squared norm of the a posteriori estimation error vector is minimized. It has the same order of computational complexity as another 2-D optimum block adaptive (TDOBA) algorithm. Computer simulations for image restoration show that the TDOBSG algorithm outperforms the TDOBA algorithm and other related algorithms in terms of objective and/or subjective measures.

[Experimental and ultrastructural study of synapses in the substantia gelatinosa after electrical acupuncture]

Ultrastructural changes of synapses in the rat substantia gelationsa of the spinal caudal trigeminal nucleus were quantitatively examined following electrical acupuncture at "Sibai" for 30 minutes. Various structural changes were observed: Spherical synaptic vesicles were clustered toward the presynaptic membrane, the number of the vesicles tended to decrease, the width of the postsyiincreased and mitochondria were also increased in the bouton. These various types of synaptic alterations related to boutons are interpreted as the morphological changes induced by the acupuncture in the region corresponding to "Sibai".

Calmodulin binds to caldesmon in an antiparallel manner

Two of the five tryptophan residues (W659 and W692) in chicken gizzard smooth muscle caldesmon (CaD) are located within the calmodulin (CaM) binding sites in the C-terminal region of the molecule. When these Trp residues are replaced with Gly in either recombinant fragments or synthetic peptides of CaD, the affinity for CaM is decreased by at least 10-fold, suggesting that both of these residues are important for the interaction of CaD with CaM. To gain information about the topography of the CaM-CaD complex, we have carried out fluorescence titrations of CaM with Tb3+ as a substitute for Ca2+ in the presence of wild-type or mutated CaD variants. By exciting Trp residues of CaD fragments or peptides while monitoring the enhanced luminescence of CaM-bound Tb3+ ions via resonance energy transfer, we were able to estimate the relative proximity between the bound metal ions in the two domains of CaM and the Trp residues of CaD. Our results suggest that in the CaM-CaD complex the metal-binding sites III and IV in the C-terminal domain of CaM are very close to W659 of CaD; the N-terminal domain of CaM appears associated with the region of CaD in the vicinity of W692, although sites I and II are relatively far away from this Trp residue. These findings are consistent with a model in which CaM binds to CaD in an antiparallel manner. Such a binding mode, however, may be flexible enough to accommodate alternative spatial arrangements when the preferred binding sites are either altered or rendered unavailable.

Stretch-dependent activation and desensitization of mitogen-activated protein kinase in carotid arteries

Arterial smooth muscle stretch is an important physiological modulator of vascular function. To identify intracellular processes altered during muscle stretch, we found previously that extracellular signal-regulated kinase-mitogen-activated protein kinase (MAPK) activity increased in response to the application of mechanical loads. In the present study, stretch-dependent activation of MAPK in porcine carotid arteries was investigated as was the phosphorylation of the thin filament-binding protein caldesmon, which is known to be a substrate for the kinase in fully differentiated smooth muscle. MAPK activity was 67 pmol.min-1.mg protein-1 in unloaded muscle strips immediately after attachment to force transducers and 139 pmol.min-1.mg protein-1 within 30 s of muscle stretch. When muscle strips were continually stretched, MAPK activity remained elevated for approximately 2 h and then decreased over 16 h to 16 pmol.min-1.mg protein-1. When muscle strips were stretched and then unloaded, MAPK activity decreased within 1 h to the level present in the muscle before the stretch. These effects of muscle stretch on MAPK activity were additive to the effects of KCl or phorbol ester stimulation and were partially inhibited by reducing extracellular Ca2+. Eliminating extracellular Ca2+ had no effect on phorbol 12,13-dibutyrate (PDBu)-dependent contractions or MAPK activity; however, KCl-dependent contractions and MAPK activity were completely abolished by this procedure. An antibody specific for detecting caldesmon phosphorylated by MAPK, vs. protein kinase C (PKC), was developed and used to assess relative caldesmon phosphorylation in unstimulated and PDBu-stimulated muscle strips. In all cases investigated, the level of MAPK activity correlated with phosphocaldesmon immunoreactivity. Because arterial MAPK activity is regulated by PKC- and stretch-dependent mechanisms, these data are consistent with a role for MAPK and the subsequent phosphorylation of caldesmon as mediators in the stretch activation of vascular smooth muscle.

Vascular endothelial growth factor, placenta growth factor and their receptors in isolated human trophoblast

The expression of the angiogenic growth factors, vascular endothelial cell growth factor (VEGF) and placenta growth factor (PIGF) was demonstrated in isolated human term cytotrophoblast and in vitro differentiated syncytiotrophoblast. RNase protection assays demonstrated VEGF expression in both cytotrophoblast and syncytiotrophoblast while prominent PIGF expression was detected in both types of trophoblast by Northern blot analyses. VEGF expression increased approximately eightfold in trophoblast cultured under hypoxic conditions (1 per cent O2) yet PIGF expression decreased 73 +/- 5.5 per cent in the same trophoblast. These results suggest distinct regulatory mechanisms govern expression of VEGF and PIGF in trophoblast. Characterization of the VEGF/PIGF receptors, KDR and flt-1, revealed the presence of flt-1 mRNA in isolated cytotrophoblast and in vitro differentiated syncytiotrophoblast. KDR was not detected in the isolated trophoblast. Exogenous rhVEGF induced c-Jun N-terminal kinase (JNK) activity in the normal trophoblast indicating that the flt-1 receptors on trophoblast are functional. Trophoblast-derived VEGF/PIGF could act in a paracrine fashion to promote uterine angiogenesis and vascular permeability within the placental bed. In addition, presence of function flt-1 on normal trophoblast suggests that VEGF/PIGF functions in an autocrine manner to perform an as yet undefined role in trophoblast invasion, differentiation, and/or metabolic activity during placentation.

Cadmium removal by a new strain of Pseudomonas aeruginosa in aerobic culture

A fluorescent pseudomonad (strain CW-96-1) isolated from a deep-sea vent sample grew at 30 degrees C under aerobic conditions in an artificial seawater medium and tolerated cadmium concentrations up to 5 mM. After 140 h, strain CW-96-1 removed > 99% of the cadmium from solution. Energy dispersive microanalysis revealed that the cadmium was removed by precipitation on the cell wall; sulfide production was confirmed by growth on Kligler's agar. Based on 16S ribosomal DNA sequencing and fatty acid analysis, the microorganism is closely related to Pseudomonas aeruginosa.

[Determation of strychnine and brucine in Strychnos by HPLC]

This paper describes the determination of strychnine and brucine in the seeds, root, stem and leaves of Strychnos species by HPLC. The analytical column used was ZY110 YNG-C18. The mobile phase was KH2PO4(0.01 mol.L-1)--MeOH(73:27), pH2.5, regulated by 10% H3PO4. Flow rate was 1.0 ml.min-1. The detection wavelength was 264 nm. The linear ranges of strychmine and brucine were 0.18-7.26 micrograms and 0.11-4.32 micrograms, respectively. The recoveries of strychnine and brucine were 98.27% and 98.04%, respectively. The analytical results showed that the contents of strychnine and brucine in samples showed great difference between different species. The contents of strychnine in the seeds of Strychnos wallichiana and S. ignatii were 5.6% and 3.9%, respectively. These results show that the two Strychnos species may be developed as the resources of strychnine.

Glutathione synthetase: similarities of the proteins from Schizosaccharomyces pombe and Arabidopsis thaliana

Glutathione synthetase predicted from the reported gene sequence from Schizosaccharomyces pombe is substantially smaller than the equivalent protein predicted from the cDNAs sequenced from Arabidopsis thaliana, Saccharomyces cerevisiae and other eukaryotes. Sequence alignments of the proteins encoded by the cDNA clones for glutathione synthetase from Arabidopsis and S. pombe show that the Arabidopsis protein contains 200 extra amino acids at the N-terminus. In order to test if this sequence is essential in the function of the protein, the full-length Arabidopsis protein and as two N-terminal deletions (Delta67-71 and Delta67-200) were expressed in S. pombe mutant MN101, which lacks endogenous glutathione synthetase activity. Although the wild-type plant cDNA could complement the yeast mutation, neither deletion mutant was able to restore glutathione-dependent cadmium resistance. When the three proteins were expressed as fusion proteins in Escherichia coli, they accumulated to the same level, but only the plasmid containing the full-length cDNA, pFLAG222, produced detectable enzyme activity in vitro. These results suggested that the N-terminus of the Arabidopsis glutathione synthetase is essential for its function and opened up the possibility that there was a sequencing error in the reported S. pombe sequence. Therefore the gsh2 sequence from wild-type S. pombe and the mutant strain MN101 were determined. The wild-type S. pombe gsh2 encodes a protein that is about the same length as that found in Arabidopsis, and the MN101 mutation involves a frameshift mutation early in the glutathione synthetase reading frame.

Phosphatidylserine liposomes can be tethered by caldesmon to actin filaments

Rotary shadowing electron microscopy revealed that attachment of caldesmon to phosphatidylserine (PS) liposomes was mainly through its C-terminal end. To determine the PS-binding sites of caldesmon, we have made use of synthetic peptides covering the two C-terminal calmodulin binding sites and a recombinant fragment corresponding to the N-terminal end of the C-terminal domain that contains an amphipathic helix. Interactions of these peptides with the PS liposomes were studied by nondenaturing gel electrophoresis and fluorescence spectroscopy. The results showed that both calmodulin-binding sites of caldesmon were able to interact with PS. The affinity (Kd) of PS for these sites was in the range of 1.8-14.3 x 10(-5) M, compared to 0.69 x 10(-5) M for the whole caldesmon molecule. Fragments located outside of calmodulin-binding sites bound PS weakly (3.85 x 10(-4) M) and thus may contain a second class of lipid-binding sites. Binding of PS induced conformational changes in regions other than the C-terminal PS-binding sites, as evidenced by the changes in the susceptibility to proteolytic cleavages. Most significantly, the presence of caldesmon greatly increased binding of PS to F-actin, suggesting that caldesmon may tether PS liposomes to actin filaments. These results raise the possibility that caldesmon-lipid interactions could play a functionally important role in the assembly of contractile filaments near the membranes.

Cutaneous microcirculation of diabetic foot: combined isolated cold stress testing and laser Doppler flowmetry study

We evaluated the peripheral microvascular response to an isolated cold stress test in patients with diabetes of various severities. We studied four groups: diabetics without neuropathy (group A: six patients), diabetics with peripheral motosensory neuropathy (group B: 12 patients), diabetics with peripheral vascular disease (group C: eight patients), and healthy controls (group D: 16 patients). Digital temperatures of all four groups decreased during the 20-minute cooling period, though more in the controls, then increased during the 20-minute rewarming period with no difference among the groups. The digital temperatures of diabetics with and without neuropathy were higher than those of diabetics with peripheral vascular disease and controls throughout. Higher mean digital skin temperature was also noted in groups A and B throughout. Significant decreases in laser Doppler flowmetry value from the last minute of acclimatization to the last minute of the cooling session were found in groups A, B, and D. A significant increase during rewarming was found only in group A (p = 0.0475). Our study showed that increased digital vascular flow was consistent with arteriovenous shunting and abnormal vascular control in diabetics with and without neuropathy. Diabetic patients with peripheral vascular disease had the lowest value and the least fluctuation in laser Doppler flowmetry, but their digital skin temperature did not differ significantly from that of the normal subjects.

Formation and persistence of DNA adducts of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in CDF1 mice fed a high omega-3 fatty acid diet

The potent bacterial mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) is carcinogenic in the CDF1 mouse, affecting the liver, lungs and forestomach. IQ forms DNA adducts in both target- and non-target organs of the CDF1 mouse. The chemopreventive effects of menhaden oil (MO), a fish oil high in omega-3 fatty acids, are well known. Because DNA adduct formation is considered to be a critical event in the initiation of carcinogenesis, we have assessed the effects of dietary MO on IQ-DNA adduct formation. For the duration of the study, young adult, male CDF1 mice were maintained on either powdered chow diet, AIN-76A diet, or AIN-76A diet modified to contain 19% MO (19% MO diet). After 2 weeks on these diets, all animals received 0.01% (w/w) IQ in the diet for the next 3 weeks. Groups of 4 animals were killed 1, 2, 4, 6, 8 or 12 days thereafter for analysis of IQ-DNA adducts by 32P-postlabeling. IQ-DNA adduct patterns were qualitatively similar in the liver, lungs, stomach, small intestine, cecum, colon, kidneys, heart and spleen. Adduct levels in the liver, lungs, stomach and colon decreased significantly during the 12-day study period, but only to a relatively small extent and only with certain of the diets. On day 1, the 19% MO diet significantly decreased (35.8-90.0%) adduct levels in the stomach, cecum, colon and kidneys, when compared to chow diet or AIN-76A diet. On day 12, adduct levels in the liver, stomach, heart and spleen were decreased (36.5-64.7%) as a result of MO feeding. With the exception of the liver, heart and spleen on day 12, there were no significant differences in organ adduct levels between the chow diet and the AIN-76A diet. It is concluded that feeding 0.01% (w/w) IQ in the diet for 3 weeks results in a relatively slow rate of adduct removal and that this rate is largely independent of the type of diet. Dietary MO inhibits IQ-DNA adduct formation only in certain target- and non-target organs of the CDF1 mouse, a finding similar to our previous results in the F344 rat. MO may affect the initiation phase of IQ tumorigenesis by inhibiting IQ-DNA adduct formation in certain target organs.

Early protein restriction and obesity independently induce hypertension in 1-year-old rats

1. Recent studies have revealed a link between fetal and early post-natal, growth retardation and the development of features of the insulin resistance syndrome in later life. Obesity is also a strong risk factor for this syndrome. The aim of this study was to assess whether maternal and early protein restriction, which causes growth retardation, and obesity are risk factors that are independent for the development of certain features of the insulin resistance syndrome, especially hypertension. 2. Pregnant Sprague-Dawley rats were given either 20% or 8% protein isocaloric diets throughout pregnancy and lactation. Female offspring were weaned onto the same diets as their mothers and they remained on these diets until 70 days of age. Half the rats were then given standard laboratory chow, whilst the remainder were fed a highly palatable cafeteria-style diet. Rats were maintained on these diets for the remainder of the study. 3. Rats given the 8% protein diet remained physically lighter than comparable animals fed the 20% protein diet throughout the study. In contrast, cafeteria-fed rats showed excessive weight gain. At 1 year of age the rats had their systolic blood pressures and fasting lipids measured, as well as undergoing an intraperitoneal glucose-tolerance test. 4. Cafeteria-fed rats had worse glucose tolerances than controls and hypertriacylglycerolaemia. The early 8% protein rats had significantly increased blood pressures, as did the cafeteria-fed rats. These increases were additive, suggesting that early protein restriction, and later obesity, are indeed independent risk factors for the development of hypertension.

Poor fetal nutrition causes long-term changes in expression of insulin signaling components in adipocytes

Insulin action on adipocytes was studied in the offspring of mothers who had been fed either a control (20% protein) or a low (8%)-protein diet during pregnancy and lactation. Adipocytes isolated from low-protein offspring had significantly higher basal and insulin-stimulated glucose uptakes than controls. This may be related to a threefold increase in insulin receptors in low-protein adipocytes. Consistent with these observed changes in glucose transport, adipocytes from low-protein animals had significantly higher basal and insulin-stimulated insulin receptor substrate (IRS)-1-associated phosphatidylinositol 3-kinase (PI 3-kinase) activities. There was also more p85-associated PI 3-kinase activity in these adipocytes. There was no difference in expression in the p85 regulatory subunit or the p110-alpha catalytic subunit of PI 3-kinase. In contrast, there was a sixfold reduction in the p110-beta catalytic subunit of PI 3-kinase in adipocytes from low-protein animals. These results suggest that poor fetal nutrition during pregnancy and lactation can have long-term effects on glucose transport and on the expression of key components of the insulin signaling pathway in adipocytes.

Hydrosalpinx fluid enhances human trophoblast viability and function in vitro: implications for embryonic implantation in assisted reproduction

OBJECTIVE

To assess the effects of hydrosalpinx fluid on human cytotrophoblast viability and function in vitro.

DESIGN

Human cytotrophoblasts obtained from third-trimester placentas were cultured in vitro with hydrosalpinx fluid, and cell viability and protein production were assayed.

SETTING

A university hospital.

PATIENT(S)

Ten hydrosalpinx fluid samples obtained from seven women with clearly diagnosed hydrosalpinges.

INTERVENTION(S)

Recovery of hydrosalpinx fluid by transvaginal aspiration or at the time of surgery.

MAIN OUTCOME MEASURE(S)

Cell viability was assessed by the XTT assay. Secretion of trophoblast oncofetal fibronectin (tropho-uteronectin) and beta-hCG by cultured trophoblasts was determined by Western blot and ELISA of the culture media.

RESULT(S)

With increasing concentrations of hydrosalpinx fluid from 0% to 20%, there was a significant increase in trophoblast cell viability (1.63-fold increase in 20% hydrosalpinx fluid). Likewise, both Western blot and ELISA assays demonstrated a significant increase in tropho-uteronectin production by trophoblasts with increasing hydrosalpinx fluid concentrations (3.76-fold increase in 20% hydrosalpinx fluid). beta-Human chorionic gonadotropin production also increased significantly in the presence of hydrosalpinx fluid (3.31-fold increase in 20% hydrosalpinx fluid).

CONCLUSION(S)

These findings suggest that hydrosalpinx fluid improves human trophoblast viability in vitro and enhances the production of tropho-uteronectin and beta-hCG by these cells.

Identification of a putative flexible loop in Arabidopsis glutathione synthetase

Glutathione synthetase catalyses the ATP-dependent ligation of gamma-glutamylcystene with glycine to form glutathione. Amino acid sequence comparisons between the Arabidopsis and the Escherichia coli proteins suggested that a region, identified as a small flexible loop that covers the active site of the E. coli protein, might be conserved in the eukaryotic protein. Three site-directed mutations in the Arabidopsis protein were generated to test this hypothesis. Two mutations within the conserved region (Lys367/ Pro368-->Asn/Ser and Gly374-->Val) inactivated the enzyme in an in vivo assay based on cadmium resistance in S. pombe, and in an in vitro assay of the activity of the enzyme expressed in E. coli. A third mutation outside of this conserved region (Leu363-->Glu) had a smaller effect in both assays. These results are consistent with the idea that this glycine-rich loop in the Arabidopsis and E. coli proteins might serve the same function in covering the active site of the enzyme.

Ultrasonographic examination of the posterior tibial tendon

The posterior tibial tendons (PTTs) of 16 patients with PTT dysfunction and 10 age-matched healthy subjects were examined ultrasonographically, using a 10-MHz linear-array transducer. Normal PTTs appeared hyperechoic (more echogenic) and oval, with an average diameter of 7.8 mm x 3.7 mm at the medial malleolar level. Degenerated PTTs appeared hypoechoic (less echogenic) and swollen (9.8 mm x 5.0 mm). Peritendinitis presented as a hypoechoic rim on the longitudinal sonogram (along the long axis of the tendon) and a "target sign" (hyperechoic central structure with a hypoechoic halo) on the transverse sonogram (at the right angle to the long axis of the tendon). Complete rupture of the PTT revealed an empty tibial groove at the level of the medial malleolus on the transverse sonogram and a wavy fibril pattern over the distal end on the longitudinal sonogram. Compared with the operative findings or the results of the magnetic resonance imaging, ultrasonography was sensitive and specific in diagnosing tenosynovitis and complete rupture of the PTT.

Fibronectinase activity in cultured human trophoblasts is mediated by urokinase-type plasminogen activator

OBJECTIVE

Human trophoblast proteolytic activity is believed to have implications for early implantation events and maintenance of chorionic structural integrity later in gestation. Abnormal release of chorion-derived extracellular matrix proteins such as fibronectin may identify patients at risk for preterm labor and delivery. The aim of this study was to characterize the enzyme(s) potentially responsible for trophoblast-mediated proteolysis of fibronectin.

STUDY DESIGN

Human term cytotrophoblasts were analyzed for their capacity to cleave fibronectin into discrete proteolytic fragments. Selective protease inhibitors were used to characterize trophoblast-derived enzymes with fibronectinase activity. Analysis and quantitation of fibronectin fragment release was determined by Western immunoblots and enzyme-linked immunosorbent assays.

RESULTS

Fibronectinase activity in trophoblast cultures was found to be both cell mediated and secreted, with the release of discrete fibronectin fragments into the media. Cell-mediated proteolytic activity could be partially inhibited by serum, whereas conditioned media containing fibronectinase activity was completely inhibited by serum, a serine protease inhibitor, and a selective inhibitor of urokinase-type plasminogen activator. Digestion of fibronectin with pure urokinase produced a similar pattern of fibronectin fragments compared with fibronectinase-generated fragments. Immunodepletion of urokinase from trophoblast media abolished fibronectinase activity.

CONCLUSIONS

Trophoblast-derived urokinase-type plasminogen activator has significant proteolytic activity in vitro with the capability of cleaving fibronectin into discrete fragments. In early pregnancy this activity could be part of the enzymatic cascade leading to uterine extracellular matrix remodeling and implantation. Later in pregnancy trophoblast derived urokinase could promote normal or inflammation-induced changes in the chorionic extracellular matrix.

Systemic lupus erythematosus in Malaysia: a study of 539 patients and comparison of prevalence and disease expression in different racial and gender groups

The aims of this study were to examine the clinical and laboratory features of Malaysian patients with systemic lupus erythematosus (SLE) and to identify any difference in disease expression between the different genders and among the three major ethnic groups of Malaysia. Retrospective analysis of all patients with SLE admitted to and followed-up at University Hospital Kuala Lumpur from 1974-90 was undertaken. Ethnic Chinese had the highest prevalence of SLE compared to other ethnic groups. There was a high incidence of renal disease, 74% of patient had significant proteinuria and half of these had associated nephrotic syndrome. Indian patients had significantly less incidence of skin manifestation compared to other racial groups. No difference in disease expression was detected between the ethnic Chinese and Indians and between the male and female patients. The overall 5 y and 10 y survival rates were 82% and 70% respectively. Indian patients had the poorest survival rates. Survival rates are similar among the Chinese and Malay patients. Our findings are in broad agreement with those previously reported.

Altered muscle insulin sensitivity in the male offspring of protein-malnourished rats

Insulin sensitivity of skeletal muscle was studied in male offspring of rat dams fed either a 20% (control) or 8% (low-protein) diet during pregnancy and lactation. Freshly isolated muscle strips took up more [3H]methylglucose from low-protein animals than from controls (19.2 +/- 2.5 and 4.26 +/- 0.45 nmol.min-1.mg muscle-1, respectively, P < 0.001). However, after a 60-min preincubation there was no significant difference in basal glucose transport (4.02 +/- 0.42 and 4.23 +/- 0.35 nmol.min-1.mg-1 for control and low-protein animals, respectively). Insulin (300 pM) had a significantly greater (P < 0.001) effect on stimulation of glucose transport into preincubated low-protein muscle strips than into controls (to 14.14 +/- 1.25 and 9.61 +/- 0.71 nmol.min-1.mg-1, respectively). There were no differences in total GLUT-4 protein content. However, subcellular fractionation revealed significantly (P < 0.001) more GLUT-4 in muscle plasma membranes of low-protein animals compared with controls. Insulin increased (P < 0.001) the GLUT-4 content of control plasma membranes but had no effect in low-protein animals. There were twofold more insulin receptors in low-protein muscle membranes compared with controls (2.35 +/- 0.17 x 10(11) and 1.28 +/- 0.10 x 10(11) and insulin receptors/mg muscle membrane protein, respectively, P < 0.01). These results suggest that programming of muscle insulin sensitivity can occur during fetal life.

SS-A/Ro antibodies in Chinese patients with systemic lupus erythematosus and Sjögren's syndrome

Serum from 53 patients with systemic lupus erythematosus (SLE) and 23 patients with primary Sjögren's syndrome (SS) were studied for anti-52-kDa SS-A/Ro, anti-60-kDa SS-A/Ro, and anti-SS-B/La antibodies by immunoblotting and enzyme-linked immunosorbent assay (ELISA). By immunoblotting, anti-SS-A/Ro was detected in 16 (30%) patients with SLE and 17 (74%) patients with SS. Anti-SS-B/La was detected in 22 (41%) patients with SLE and 15 (65%) patients with SS. Serum from 14 of the 16 SLE patients with anti-SS-A/Ro reacted with the 60-kDa protein and 15 serum samples from these patients recognized the 52-kDa protein. Serum with anti-60-kDa SS-A/Ro alone was not found. Serum from all of the 17 SS patients with anti-SS-A/Ro reacted with the 52-kDa protein, whereas serum from only two of these patients recognized the 60-kDa protein. By ELISA, the frequency of anti-SS-A/Ro (antibodies to the 60-kDa and/or 52-kDa of SS-A/Ro proteins) in patients with SLE and SS was 43/53 (81%) and 15/23 (65%), respectively. Anti-48-kDa SS-B/La was found in 28% and 48% of SLE and SS patients, respectively. Serum from 77% of SLE patients and 48% of SS patients reacted with the 60-kDa SS-A/Ro protein. Serum from 45% of SLE patients and 52% of SS patients reacted with the 52-kDa SS-A/Ro protein. Patients with SLE had significantly higher titers of antibodies to 60-kDa SS-A/Ro compared with patients with SS. Anti-SS-A/Ro and anti-SS-B/La are common in both SLE and SS. The different reactivities of anti-52-kDa and anti-60-kDa antibodies in serum from patients with SLE and SS may represent differences in conformation-dependent epitopes of SS-A/Ro autoantigens.

Affinity and structure of complexes of tropomyosin and caldesmon domains

The interaction of caldesmon domains with tropomyosin has been studied using x-ray crystallography and an optical biosensor. Only whole caldesmon and the carboxyl-terminal domain of caldesmon (CaD-4, chicken gizzard residues 597-756) bound to tropomyosin with greater than millimolar affinity at 100 and 150 microM salt. Under these conditions the affinities of whole caldesmon and CaD-4 were both in the micromolar range. Data from the x-ray studies showed that whole caldesmon bound to tropomyosin in several places, with the region of tightest interaction being at tropomyosin residues 70-100 and/or 230-260. Studies with CaD-4 revealed that this region corresponded to the strong binding site seen with whole caldesmon. Weaker association of other regions of caldesmon to tropomyosin residues 180-210 and 5-50 was also observed. The results suggest that the carboxyl-terminus of caldesmon binds tightly to tropomyosin and that other regions of caldesmon may interact with tropomyosin tightly only when they are held close to tropomyosin by the carboxyl-terminal domain. Four models are presented to show the possible interactions of caldesmon with tropomyosin.

Cloning of the cDNA and genomic clones for glutathione synthetase from Arabidopsis thaliana and complementation of a gsh2 mutant in fission yeast

Glutathione is essential for protecting plants from a range of environmental stresses, including heavy metals where it acts as a precursor for the synthesis of phytochelatins. A 1658 bp cDNA clone for glutathione synthetase (gsh2) was isolated from Arabidopsis thaliana plants that were actively synthesizing glutathione upon exposure to cadmium. The sequence of the clone revealed a protein with an estimated molecular mass of 53858 Da that was very similar to the protein from higher eukaryotes, was less similar to the gene from the fission yeast, Schizosaccharomyces pombe, and shared only a small region of similarity with the Escherichia coli protein. A 4.3 kb SstI fragment containing the genomic clone for glutathione synthetase was also isolated and sequenced. A comparison of the cDNA and genomic sequences revealed that the gene was composed of twelve exons. When the Arabidopsis cDNA cloned in a special shuttle vector was expressed in a S. pombe mutant deficient in glutathione synthetase activity, the plant cDNA was able to complement the yeast mutation. Glutathione synthetase activity was measurable in wild-type yeast cells, below detectable levels in the gsh2- mutant, and restored to substantial levels by the expression of the Arabidopsis cDNA. The S. pombe mutant expressing the plant cDNA had near wild type levels of total cellular thiols, 109Cd2+ binding activity, and cadmium resistance. Since the Arabidopsis cDNA was under control of a thiamine-repressible promoter, growth of the transformed yeast on thiamine-free medium increased expression of the cDNA resulting in increases in cadmium resistance.

Anti-IgM-mediated regulation of c-myc and its possible relationship to apoptosis

Anti-IgM treatment of Burkitt's lymphoma cells is followed by either growth arrest or induction of apoptosis. In this study we have explored the role of c-myc in these events. Our results in Ramos cells indicate the following. (a) The decline in c-myc mRNA occurs at about 4 h; inhibition of about 80% being observed. (b) The stability of c-myc message is involved since the half-life of c-myc mRNA is decreased from about 30 min in untreated cells to about 15 min following treatment with anti-IgM. In the presence of cycloheximide, a protein synthesis inhibitor, the half-life is increased to about 50 min and was unaltered by treatment with anti-IgM. (c) By contrast, nuclear run-on experiments indicated no change in transcription rates for c-myc message due to treatment with anti-IgM. (d) A decrease in c-myc causes apoptosis since specific repression of c-myc with antisense oligonucleotides decreases the levels of c-Myc, inhibits growth rate, decreases viability, and induces apoptosis. (e) Anti-CD40 inhibition of apoptosis occurs without alteration in anti-IgM-induced down-regulation of c-myc mRNA, suggesting that it acts distally to c-myc down-regulation. Other cell lines were also investigated. In Epstein-Barr virus (EBV)-positive cell lines (Daudi, Raji, and Namalwa), anti-IgM treatment for 24 h results in growth inhibition without induction of apoptosis. In EBV-negative cell lines (ST486 and CA46, as well as Ramos), a more heterogeneous pattern of responses to anti-IgM are observed. Ramos and ST486 cells both show growth inhibition and apoptosis upon anti-IgM treatment; CA46 cells shown only growth inhibition but not apoptosis. Anti-IgM causes a decline in c-myc mRNA levels in all of these lines, as well as in c-Myc protein level in the two lines investigated, Daudi and Ramos, regardless of apoptosis. Addition of antisense c-myc oligonucleotides to the cells reduced growth in both Daudi and Ramos cells lines, however it resulted in substantial apoptosis only in Ramos cells. These results suggest that anti-IgM destabilizes c-myc mRNA by a process that involves mRNA turnover, rather than transcription rates. However anti-IgM exerts differential effects in EBV-positive and EBV-negative cell lines. EBV-positive cells are uniformly resistant to apoptosis, while EBV-negative cell lines show a tendency to apoptosis but with exceptions. Growth inhibition can be uncoupled from apoptosis in EBV-positive cell lines, but not in those EBV-negative cell lines prone to apoptosis. Furthermore, down-regulation of c-myc message correlates with growth inhibition in these cells, but is an insufficient link to apoptosis. By contrast inhibition of apoptosis by anti-CD40 occurs even though c-myc mRNA is decreased.

TNF-alpha inhibits anti-IgM-mediated apoptosis in Ramos cells

We have examined the effects of tumor necrosis factor-alpha (TNF-alpha) as an inducer or modulator of necrosis and/or apoptosis in B cell lines. TNF-alpha does not induce either necrosis or apoptosis in EBV-positive or -negative cell lines, regardless of the culture conditions of the cells or the presence or absence of cytokines. By contrast anti-IgM induces apoptosis in two EBV-negative cell lines (Ramos and ST486) but not in EBV-positive cell lines. Since TNF receptor and CD40 belong to the TNF receptor superfamily and anti-CD40 is a known inhibitor of apoptosis, we tested for TNF-alpha's effects on the inhibition of apoptosis induced by anti-IgM. Our results indicate that TNF-alpha inhibits apoptosis induced by anti-IgM in Ramos cells but not in ST486. The effects are dose and time dependent; the degree of apoptosis achieved and the selectivity of the effect among cell lines are strikingly similar for both TNF-alpha and anti-CD40. Furthermore when both agents are tested together no additivity in the inhibition is observed. The inhibition of apoptosis is a direct effect of TNF-alpha and not a permissive effect of another cytokine, since it is observed in defined medium. Although anti-IgM induces both TNF-alpha secretion and TNF receptors in Ramos cells, the concentration of secreted TNF-alpha is too low to affect apoptosis. Inhibition does not involve perturbation of the cell cycle distribution of Ramos cells. Furthermore rapid induction of c-fos and the decrease in c-myc observed after anti-IgM treatment are both unaltered by TNF-alpha. Our results suggest that TNF-alpha is an inhibitor of apoptosis in Ramos cells, that its overall pattern of inhibition is similar to that of anti-CD40, and that both agents act at some point distal to the alteration of c-fos and c-myc by anti-IgM.

When do human macrophages release nitric oxide? Variable effects of certain in vitro cultural and in vivo resident conditions

Nitric oxide (NO) release from mouse and rat macrophages is implicated in tumor cell cytotoxicity and the killing of intracellular organisms. Evidence, however, suggests that human monocyte-derived macrophages or myeloid leukemic cells differentiated along the monocytic lineage do not consistently release NO. Results presented herein that human monocyte-derived macrophages in response to lipopolysaccharide can release NO, but markedly less than mouse macrophages (1.26 +/- 0.20 vs 42.5 +/- 6.3 microM). Different in vitro and in vivo conditions have variable effects on NO production by human macrophages. Monocytes cultured in plastic wells, but not teflon beakers, for 7 days can release NO (1.22 +/- 0.13 vs 0.14 +/- 0.07 microM). In addition, human resident macrophages derived from patients with certain diseases possess a calcium- and protein kinase C-dependent pathway to produce NO, in contrast to the calcium-independent and phosphatase-dependent NO release in murine macrophages. Above results suggest that the mechanism of producing NO by macrophages in humans is not only different from that in mice, but also depends on certain in vitro and in vivo conditions.

(i, i + 4) Ion pairs stabilize helical peptides derived from smooth muscle caldesmon

The central region of smooth muscle caldesmon contains 10 repeats of a 13-amino-acid residue motif that is rich in charged side chains. This region has been predicted to have a strong alpha-helical propensity, and the helical structure was thought to be stabilized by the interactions between oppositely charged side chains of residues at positions i and i + 4 (Wang, C.-L. A., Chalovich, J.M., Graceffa, P., Lu, R.C., Mabuchi, K, and Stafford, W.F., J.Biol. Chem. 266, 13958-13963, 1991). Two synthetic peptides corresponding to these repeats, each containing 25 and 60 amino acid residues, indeed assume an alpha-helical conformation that is stable over a wide range of salt concentration and pH, and exhibit a typical helix-coil transition upon heating. Most significantly, when the amino acid sequence of the 25-mer is randomized without losing the i-to-i + 4 ion pairs, the peptide maintains a helical content comparable to that of the wild-type peptide, whereas another peptide variant with a sequence rearranged to eliminate all i-to-(i + 4) ion pairs has much less helicity, suggesting that specific interactions between residues with (i,i + 4) spacings are important determinants for the maintenance of secondary structure in this region of caldesmon.

Immunocytochemical localization of caldesmon and calponin in chicken gizzard smooth muscle

The distribution of caldesmon and calponin in chicken gizzard smooth muscle was investigated with immunofluorescence and immunogold electron microscopy. Immunofluorescence microscopy showed that in verapamil treated (relaxed) muscles the distributions of caldesmon and myosin appeared to be uniform throughout the cytoplasm, but clearly more textured than that of actin filaments as revealed by the distribution of tropomyosin. In shortened muscles both caldesmon and myosin became segregated, in contrast to the distribution of actin, which remained uniform. The distribution of calponin was even more textured, with no similarity to those of caldesmon or myosin. Instead, considerable overlap was observed between calponin and the cytoskeletal protein desmin and, to a lesser extent, beta-actin. By immunogold electron microscopy caldesmon appeared mostly near and around myosin filaments in both relaxed and shortened muscle. Calponin, on the other hand, was found primarily at the periphery of cytoskeletal structures in the same general region as desmin, and very often adjacent to beta-actin, which is mainly in the core. These observations indicated that caldesmon and calponin are associated with different subsets of actin filaments, caldesmon with contractile actin, while calponin with cytoskeletal actin. Thus the in situ localization of caldesmon is consistent with its proposed regulatory function. Calponin, on the other hand, is unlikely to directly regulate actomyosin interactions in these cells; instead, it may function as a bridging protein between the actin and the intermediate filament networks.

Ca2+-dependent binding of calcyclin to muscle tropomyosin

The interaction of calcyclin with tropomyosin and tropomyosin-actin was studied with fluorescence titrations and photo-reactive crosslinking experiments. Titrations of pyreneiodoacetamide-labeled tropomyosin alone or with actin showed binding of calcyclin to tropomyosin with muM dissociation constants when Ca2+ was present. UV irradiation of mixtures of calcyclin and gizzard beta beta-tropomyosin labeled with benzophenone-iodoacetamide at Cys36, with or without actin, produced crosslinks between tropomyosin chains and calcyclin monomers only in the presence of Ca2+. These data provide direct evidence for a Ca+2-dependent tropomyosin-calcyclin interaction at or near Cys36 of tropomyosin and indicate that calcyclin binding to tropomyosin-actin does not cause tropomyosin dissociation.

Prevalence and clinical significance of antibodies to ribonucleoproteins in systemic lupus erythematosus in Malaysia

One hundred and seventy patients with systemic lupus erythematosus (SLE) were studied for the prevalence of antibodies to the small RNA-associated proteins Ro/SSA, La/SSB, Sm, U1RNP and Sm. The relationship of these autoantibodies to different races, sexes and clinical manifestations of SLE was evaluated. Passive immunodiffusion was employed using human spleen extract as antigen source for Ro and rabbit thymus extract for La, Sm and U1RNP. We found the prevalence of antibodies to be as follows: anti-Ro/SSA, 36%; anti-La/SSB, 8%; anti-Sm, 15% ; anti-U1RNP, 21%. Except for a low prevalence of anti-La, the prevalence of these antibodies was similar to that in Western studies, The prevalence of anti-Ro/SSA is similar to that reported in the Western studies, but lower than that reported in the Oriental patients from Singapore and Hong Kong. Linkages of anti-Ro with anti-La antibodies were usual; however, although anti-Sm antibodies were usually associated with anti-U1RNP, they were more frequently associated with anti-Ro antibodies. The Malay patients had a high prevalence of anti U1RNP compared to other races. No gender difference was detected. Anti-Sm antibody was associated with serositis and anti-U1RNP antibodies with Raynaud's phenomenon. No association was found between the presence of skin renal or cerebral manifestations and any specific antibodies or combination of antibodies.

[A comparison of compression stockings of different pressures with lower leg edema in spinal cord injury or lesions patients]

We tested 80 spinal cord injury or lesion patients admitted to Department of Rehabilitation Medicine of Chang Gung Memorial hospital from Jan, 1994 to Aug, 1994, in order to assess the effectiveness of compression stockings of different pressures. The study group consisted of patients who, after leaving bed for 4 hours, had a volume change in the lower extremities greater than 50 c.c., as measured by a specially designed water bucket. One of the lower limb was used as the control group and the other limb was used as the experimental group. Different stocking compression pressure, 12 mmHg 20 mmHg, and 30 mmHg, were used for the experimental limb. No placebo stocking was used in the control group. Change in the lower limb volume and degree of comfort after leaving bed for 4 hours were measured. The experimental results reveal that wearing stocking with compression pressure, 12 mmHg, 20 mmHg, 30 mmHg, had therapeutic effects (P < 0.01). The therapeutic effects of the 12 mmHg stocking was less than the 20 mmHg and 30 mmHg stocking. There was no significant difference between the therapeutic effects of the 20 mmHg and 30 mmHg stocking. As for the degree of comfort, 12 mmHg was better than 20 mmHg, and 20 mmHg better than 30 mmHg. When choosing the type of compression stocking to treat lower leg edema in spinal cord injury or lesion patients, we suggest starting with 20 mmHg compression pressure stockings would be a better choice, as they are cheaper, more comfortable to wear and can provide the same therapeutic effects as 30 mmHg compression stockings.