Dissecting the nucleotide binding properties of Escherichia coli 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase with fluorescent 3'(2)'-o-anthraniloyladenosine 5'-triphosphate

6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the transfer of pyrophosphate from ATP to 6-hydroxymethyl-7, 8-dihydropterin, the first reaction in the folate biosynthetic pathway. Like other enzymes in the folate pathway, HPPK is an ideal target for development of antimicrobial agents because the enzyme is essential for microorganisms but is absent from humans and animals. Using 3'(2')-o-anthraniloyladenosine 5'-triphosphate as a fluorescent probe, a fluorometric competitive binding assay has been developed for measuring the dissociation constants of various compounds that bind to the ATP site of HPPK. The fluorometric assay has been used to determine the nucleotide specificity and dissect the energetics of the binding of MgATP. The order of affinity of various nucleoside triphosphates for HPPK is MgATP>MgGTP>MgITP>MgXTP approximately MgUTP approximately MgCTP. The affinity of MgATP for HPPK (K(d)=2.6+/-0.06 microM) is 260-fold higher than that of MgGTP and more than 1000-fold higher than those of the other nucleoside triphosphates, indicating that HPPK is highly specific with respect to the base moiety of the nucleotide. The affinity of ATP for HPPK in the presence of Mg(2+) is 15 times that in the absence of Mg(2+), indicating that the metal ion is important for the binding of the nucleotide. Removal of the gamma-phosphate from MgATP reduces its affinity for HPPK by a factor of approximately 21. The affinity of AMP for HPPK is about one third that of ADP and almost the same as that of adenosine. The result suggests that among the three phosphoryl groups of MgATP, the gamma-phosphoryl group is most critical for binding to HPPK and the alpha-phosphoryl group contributes little to the binding of the nucleotide. The affinity of MgATP is 18 times that of MgdATP, indicating that the 2'-hydroxyl group of MgATP is also important for binding. van't Hoff analysis suggests that binding of MgATP is mainly driven by enthalpy at 25 degrees C and the entropy of binding is also in favor of the formation of the HPPK.MgATP complex.

Does the route of feeding modify gastric emptying in rats?

BACKGROUND

It has been shown that the pattern of previous nutrient intake can influence gastric emptying. However, the effect of the absence of enteral stimulation in the setting of a normal energy supply on gastric emptying has not been examined. The aim of this study was to determine whether the absence of enteral stimulation during total parenteral nutrition (TPN) could modify gastric emptying in rats.

METHODS

Two experiments were performed. First, gastric emptying of a peptone meal was compared between rats receiving TPN, oral liquid diet (same solution as TPN), or regular diet (control group) for 10 days. In the second experiment, gastric emptying of two test meals (40% peptone and 25% glucose) was studied before and after rats received TPN or intragastric nutrition (same solution as TPN) for 10 to 12 days.

RESULTS

In experiment 1, gastric emptying of 40% peptone in the TPN and liquid diet groups was slower than that in the control group. This difference was significant between the TPN group and the control group (p < .01) but not between the liquid diet and control groups (p = .076). Gastric emptying of this meal in the TPN and liquid diet groups was similar. In experiment 2, no difference in gastric emptying of 40% peptone or 25% glucose was found between rats receiving TPN and those receiving intragastric nutrition for 10 to 12 days.

CONCLUSIONS

The composition of diet not the route of feeding is important in the modification of gastric emptying by the pattern of previous nutrient intake.

Increased frequency of transient lower esophageal sphincter relaxation induced by gastric distention in reflux patients with hiatal hernia

BACKGROUND & AIMS

This study aimed to determine if hiatal hernia influences vulnerability to reflux and transient lower esophageal sphincter relaxation (tLESR) during gastric distention in patients with gastroesophageal reflux disease (GERD).

METHODS

Eight normal subjects and 15 patients with GERD were studied. A metal clip attached to the squamocolumnar junction (SCJ) was beneath the hiatus in all control subjects. Eight GERD patients with >/=1-cm SCJ-hiatus separation were considered hernia patients, and 7 with <1-cm separation were considered nonhernia patients. Manometry and esophageal pH were recorded for 30 minutes, after which the stomach was loaded with acid dextrose and the recording continued for 2 hours with intragastric air infusion of 15 mL/min.

RESULTS

Baseline reflux was comparable among groups. Gastric distention increased the frequency of reflux by the tLESR mechanism in all groups. Controls and nonhernia patients had median increases of 4.0 and 4.5 in tLESR frequency, respectively, and hernia patients had a median increase of 9.5/h. tLESR frequency was highly correlated with the SCJ-hiatus separation (r = 0.76; P < 0.001).

CONCLUSIONS

Gastric air infusion was a potent stimulus for tLESR and reflux. The resultant tLESR frequency was directly proportional to the separation between the SCJ and hiatus, suggesting that the perturbed anatomy associated with hiatal hernia predisposed to eliciting tLESRs in patients with GERD.

[The multicolour three-photon resonant ionization spectrum studies in uranium atom]

The multicolour three-photon resonant ionization spectra of 238U were measured by using the pulsed dye lasers system synchronously pumped by a frequency doubled Nd:YAG-laser 532 nm output(operated at 10 Hz), a device for atomic beam of U, time-of-flight mass spectrometer and boxcar integrator. The dye laser pulses have a 6 ns duration. Beams from the dye lasers, which have the same polarization direction and are focused by lenses, entered an interaction chamber through opposite windows on a common axis and spatially overlapped the U atomic beam. The optical pulse from dye laser DL2 was delayed to arrive at the interaction region 8 ns after the pulse from dye laser DL1; in the same way, the pulse from DL3 was delayed 8 ns after from DL2. The atomic beam device was made from stainless steel. We generated the U vapor by heating solid U in a graphite crucible by e-type electron-field on first excited states were studied in uranium atom. The question how to determine single-colour, two-colour and three-colour three-photon resonant ionization peak in the three-colour three-photon resonant ionization spectra diagram were solved.

Esophagogastric junction pressure topography after fundoplication

OBJECTIVES

This study compared the pressure topography after laparoscopic Nissen fundoplication to that of normal subjects and patients with hiatal hernia and reflux disease.

METHODS

Seven patients with fundoplication, 7 normal subjects and 7 patients with hiatal hernia, were studied. The squamocolumnar junction and intragastric margin of the esophagogastric junction (EGJ) were marked with metal clips. Axial and radial characteristics of EGJ pressure were mapped relative to the hernia and clipped during concurrent fluoroscopy and manometry. Responses to inspiration and abdominal compression were also analyzed.

RESULTS

Fundoplication modifies the EGJ by restoration of the hiatal component of EGJ pressure and elongation of the subdiaphragmatic component. Maximal EGJ pressure after fundoplication is mainly dependent on the extrinsic effect of the hiatal canal that compresses the esophagus; the resultant length of the EGJ reflects the length of the fundic wrap. Integrity of the EGJ after fundoplication is independent of the intrinsic lower esophageal sphincter itself.

CONCLUSIONS

Fundoplication alters the pressure topography of the EGJ by reducing the hiatal hernia, tightening the hiatal orifice, and constructing a subdiaphragmatic wrap of variable length. Each effect depends on different technical aspects of the surgery with the potential of substantial variability in the resultant pressure topography.

[6A8 cDNA encodes A type of alpha-mannosidase]

OBJECTIVE

To find the nature of the protein encoded by 6A8 cDNA.

METHODS

In the light of that the ligand of Con A is mannoses and that the function of alpha-mannosidase is trimming of mannoses in the oligosaccharide chains of glycoproteins, COS-7 cells and CNE-2L2 cells, a cloned cell line of human nasopharyngeal carcinoma, were transfected with pRc/CMV-sense 6A8 cDNA or pRc/CMV-antisense 6A8 cDNA and the Con A binding to the cells was examined upon a lazer scan confocal microscope.

RESULTS

The data demonstrated that with transfection of pRc/CMV-sense 6A8 cDNA the binding of Con A to the cells was decreased, but the staining of the cells with mAb 6A8 was enhanced, and vise versa for the cells with transfection of pRc/CMV-antisense 6A8 cDNA.

CONCLUSIONS

The protein encoded by 6A8 cDNA might be a type of alpha-mannosidase recognized by mAb 6A8.

[A light and scanning electron microscopic study of primary teeth in hypophosphatasia]

OBJECTIVE

To investigate the features of primary tooth structure in hypophosphatasia.

METHODS

Three primary teeth from two patients at age of 3 yr-6 month and 4 yr-2 month, who were diagnosed hypophosphatasia. The structural changes of these teeth were examined by light microscopy, polarizing microscopy and scanning electron microscopy.

RESULTS

The complete absence of cementum was a prominent feature in all the teeth, three small island-shape cementun areas were found in scanning electron microscopy. A large number of resorptions were found on the root surfaces, particularly near apical portions of roots. The main findings included disturbances of dentin mineralization, hypoplasia or aplasia of root cementum and external resorption of root dentin.

CONCLUSION

The hypoplasia or aplasia of root cementum was thought to be the prime etiological factor in the early loss of primary teeth.

[Simultaneous determination of tungsten, molybdenum and titanium by k-factor dual-wavelength standard addition method]

In this paper, a new method for simultaneous spectropthotometric determination of tungsten, molybdenum and titanium is proposed. The method is based on the difference of absorption spectra of the three elements forming coloured complexes with PF in acidic medium and in the presence of nonionic surfactant Tween-80. The absorbance of sample was measured at wavelengths of 503, 530 and 560 nm, and the data were treated by the principle of the k coefficients and dual-wavelength standard addition method. The method has been applied to the determination of tungsten, molybdenum and titanium in steels, and satisfactory results were obtained.

Esophageal sensitivity and symptom perception in gastroesophageal reflux disease

Patients with gastroesophageal reflux disease (GERD) experience a wide spectrum of symptoms, varying both in quality and severity. This review summarizes clinical observations of esophageal sensitivity and symptom perception in GERD patients. The Bernstein test, although lacking standardization, remains a useful tool in determining esophageal sensitivity to acid stimuli. Ambulatory 24-hour pH monitoring with symptom event marking and subsequent symptom-reflux correlation between acid reflux events and esophageal symptomatology now provides an alternative method for establishing esophageal acid sensitivity. The intraesophageal balloon distention test (IEBD) was developed to assess esophageal sensitivity to mechanical stimuli. Variants of each of these tests have been applied to the evaluation of uncomplicated GERD patients and patients with esophagitis and Barrett's metaplasia, who generally demonstrate less esophageal sensitivity than the former group. Studies using these methods have demonstrated increased esophageal sensitivity in patients with esophageal chest pain and have also identified a subset of patients with esophageal symptoms yet normal esophageal acid exposure, a condition referred to as "hypersensitive esophagus." The Bernstein test, 24-hour pH monitoring with symptom assessment, and IEBD have each contributed to our understanding of esophageal pain syndromes; it is hoped that future work in this area will lead to improved and more specific therapy for these patients.

Esophageal solid bolus transit: studies using concurrent videofluoroscopy and manometry

OBJECTIVE

Our aim was to assess the efficacy and mechanism of solid bolus transit through the esophagus.

METHODS

Eight healthy volunteers were studied with concurrent manometry and videofluoroscopy while swallowing 5 ml liquid barium, a 5-6 mm diameter bread ball, and 4 g chewed bread in both a supine and upright posture. As many as four successive swallows were performed until clearance was achieved.

RESULTS

The esophageal clearance of liquid barium was 100% with the first swallow. Clearance of the unchewed bread ball occurred with the first swallow in only 6.7% of trials in the upright posture and 5.9% in the supine posture. After four swallows, clearance was 100% and 52.9% in the upright and supine postures, respectively. Chewed bread was more readily cleared than unchewed bread, with 100% clearance after two swallows in the upright posture and 91% clearance after four swallows in the supine posture. The most common locus of bread stasis was at the aortic arch and carina. The bread boluses were noted to move more effectively when localized in the head as opposed to the tail of the bolus composite. Nonocclusive contractions often occurred at the bolus tail despite the increased peristaltic amplitude seen with the chewed bread. Failed peristalsis, a frequent cause for solid clearance failure, was observed during 30% of all bread swallows. This usually occurred distal to the stopping point of the bolus, suggesting it to be the result rather than the cause of impaired transit.

CONCLUSIONS

Although infrequently perceived by these normal subjects and in contradistinction to liquid clearance, bread is rarely cleared from the esophagus with a single swallow. Mastication and an upright posture facilitate the esophageal transport of solids. Bolus composition and impaired bolus transit alter the amplitude and conductance of peristalsis. Manometric data pertaining to liquid clearance through the esophagus do not readily apply to bread.

Crystal structure of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase, a potential target for the development of novel antimicrobial agents

BACKGROUND

Folate cofactors are essential for life. Mammals derive folates from their diet, whereas most microorganisms must synthesize folates de novo. Enzymes of the folate pathway therefore provide ideal targets for the development of antimicrobial agents. 6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the transfer of pyrophosphate from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP), the first reaction in the folate biosynthetic pathway.

RESULTS

The crystal structure of HPPK from Escherichia coli has been determined at 1.5 A resolution with a crystallographic R factor of 0.182. The HPPK molecule has a novel three-layered alpha beta alpha fold that creates a valley approximately 26 A long, 10 A wide and 10 A deep. The active center of HPPK is located in the valley and the substrate-binding sites have been identified with the aid of NMR spectroscopy. The HP-binding site is located at one end of the valley, near Asn55, and is sandwiched between two aromatic sidechains. The ATP-binding site is located at the other end of the valley. The adenine base of ATP is positioned near Leu111 and the ribose and the triphosphate extend across and reach the vicinity of HP.

CONCLUSIONS

The HPPK structure provides a framework to elucidate structure/function relationships of the enzyme and to analyze mechanisms of pyrophosphoryl transfer. Furthermore, this work may prove useful in the structure-based design of new antimicrobial agents.

Differential asparagine-linked glycosylation of voltage-gated K+ channels in mammalian brain and in transfected cells

Glycosylation of ion channel proteins dramatically impacts channel function. Here we characterize the asparagine (N)-linked glycosylation of voltage-gated K+ channel alpha subunits in rat brain and transfected cells. We find that in brain Kv1.1, Kv1.2 and Kv1.4, which have a single consensus glycosylation site in the first extracellular interhelical domain, are N-glycosylated with sialic acid-rich oligosaccharide chains. Kv2.1, which has a consensus site in the second extracellular interhelical domain, is not N-glycosylated. This pattern of glycosylation is consistent between brain and transfected cells, providing compelling support for recent models relating oligosaccharide addition to the location of sites on polytopic membrane proteins. The extent of processing of N-linked chains on Kv1.1 and Kv1.2 but not Kv1.4 channels expressed in transfected cells differs from that seen for native brain channels, reflecting the different efficiencies of transport of K+ channel polypeptides from the endoplasmic reticulum to the Golgi apparatus. These data show that addition of sialic acid-rich N-linked oligosaccharide chains differs among highly related K+ channel alpha subunits, and given the established role of sialic acid in modulating channel function, provide evidence for differential glycosylation contributing to diversity of K+ channel function in mammalian brain.

Lower esophageal sphincter relaxation characteristics using a sleeve sensor in clinical manometry

OBJECTIVE

We undertook this study to determine the characteristics of swallow-induced lower esophageal sphincter (LES) relaxation in the setting of clinical manometry using a standardized methodology.

METHODS

We reviewed 170 manometric recordings performed using a perfused manometric assembly with a sleeve sensor and a computer polygraph. Patients were categorized as patient controls, gastroesophageal reflux disease (GERD), diffuse esophageal spasm (DES), or achalasia. Tracing were semiautomatically analyzed for basal LES pressure, LES pressure during deglutitive relaxation (relaxation LES pressure), duration of LES relaxation, timing of LES relaxation, and the success rate of primary peristalsis.

RESULTS

Forty-six patient controls, 93 with GERD, five with DES, and 26 with achalasia were identified. GERD and achalasia patients had lower or higher basal LES pressures than patient controls, respectively. Compared with patient controls, achalasia patients had higher relaxation LES pressures, lower percent LES relaxation, and shorter durations of LES relaxation. The best single measure for distinguishing achalasia was the relaxation LES pressure; using the 95th percentile value of patient controls (12 mm Hg) as the upper limit of normal, its sensitivity and positive predictive value for the diagnosis of achalasia were 92% and 88%, respectively. Coupled with the finding of aperistalsis, a relaxation LES pressure > or = 10 mm Hg achieved 100% sensitivity and positive predictive value among these patients.

CONCLUSIONS

Sleeve sensor recording is a practical method for clinical manometry that reliably records LES relaxation characteristics and is amenable to both a standardized manometry protocol and a semiautomated analysis routine. Relaxation LES pressure has a high diagnostic value for achalasia.

Neuroendocrine synaptic vesicles are formed in vitro by both clathrin-dependent and clathrin-independent pathways

In the neuroendocrine cell line, PC12, synaptic vesicles can be generated from endosomes by a sorting and vesiculation process that requires the heterotetrameric adaptor protein AP3 and a small molecular weight GTPase of the ADP ribosylation factor (ARF) family. We have now discovered a second pathway that sorts the synaptic vesicle-associated membrane protein (VAMP) into similarly sized vesicles. For this pathway the plasma membrane is the precursor rather than endosomes. Both pathways require cytosol and ATP and are inhibited by GTPgammaS. The second pathway, however, uses AP2 instead of AP3 and is brefeldin A insensitive. The AP2-dependent pathway is inhibited by depletion of clathrin or by inhibitors of clathrin binding, whereas the AP3 pathway is not. The VAMP-containing, plasma membrane-derived vesicles can be readily separated on sucrose gradients from transferrin (Tf)-containing vesicles generated by incubating Tf-labeled plasma membrane preparations at 37 degreesC. Dynamin- interacting proteins are required for the AP2-mediated vesiculation from the plasma membrane, but not from endosomes. Thus, VAMP is sorted into small vesicles by AP3 and ARF1 at endosomes and by AP2 and clathrin at the plasma membrane.

[Studies on the functional anatomy of Golgi-phobic dendrites of spinal motoneurons in rats--different dendroarchitectures of the motoneurons to slow muscle and fast one]

OBJECTIVE

The functional anatomy of Golgi-phobic dendrites (GBD) of spinal motoneurons (Mn) in rats was studied from their postnatal development.

METHODS

Cholera toxin B subunit conjugated with horseradish peroxidase (CB-HRP) retrograde labelling method was mainly used.

RESULTS

In the extensor digitorum longus Mn pool (EDL-Mn) GBD gradually decrease during development and are only a few in adults. The related value of the surface density of the white matter dendrites, most of them are GBD, of the soleus Mn pool (SOL-Mn) is nearly double than that of EDL-Mn.

CONCLUSIONS

GBD of motoneurons might be related to their action patterns, especially the tonic action of slow muscle, such as the soleus. The hypotheis of dual circuits in motor control, the paralateral circuit on GBD regulates control of tonic action and the core circuit on Golgi-philic dendrites (GLD) and somata regulates phasic action, such as on EDL-Mn, has been further enhanced.

[Value of pulmonary diffusion capacity in predicting the short-term prognosis after lung resection in lung cancer patients.]

BACKGROUND

To determine the relationship between pulmonary diffusion capacity (DLCO) and the short-term prognosis after lung resection in patients with lung cancer.

METHODS

A retrospective analysis of 413 consecutive patients with lung cancer who underwent lung resection was performed. Among them , 27 had low DLCO before operation (DLCO < 60 %predicted for total pneumonectomy or bilobectomy , < 50 %predicted for lobectomy) , as a low DLCO (LDLCO) group ,and other 386 patients as a control group.

RESULTS

There were more patients with chronic bronchitis , history of heavy smoking and underwent chemotherapy or radiotherapy preoperatively in LDLCO group than those in control group. The hospital mortality rates within 30 days after lung resection were no significant difference between the two groups ( P > 0. 05) ,whereas incidence of respiratory complications in LDLCO group was higher than that in control group ( P < 0. 05) .

CONCLUSIONS

A reduction in DLCO before operation can remarkably increase respiratory complications after pulmonary resection. DLCO is one of important predictors of risk for lung resection.

On-demand treatment of gastro-oesophageal reflux symptoms: a comparison of ranitidine 75 mg with cimetidine 200 mg or placebo

AIM

To compare the effects of ranitidine 75 mg with those of either cimetidine 200 mg or placebo given on demand for relief of typical symptoms of gastro-oesophageal reflux disease during a 15-day period.

METHODS

A total of 1336 patients (aged > or = 18 years) with heartburn episodes were recruited and randomly assigned to a ranitidine 75 mg, cimetidine 200 mg or placebo group. Depending on the occurrence or persistence of heartburn, treatment was administered as required up to three times daily, with at least 2 h between drug doses. Antacids were allowed as rescue medication if symptoms persisted for at least 2 h after the third medication on any given day. The primary end-point was defined as the proportion of patients with relief of at least 75% of heartburn episodes during the study period (i.e. relief occurring within 2 h after drug ingestion and lasting for at least 5 h).

RESULTS

Analysis was performed in an intention-to-treat population comprising 504 subjects in the ranitidine group, 515 in the cimetidine group and 270 in the placebo group. Primary end-point success rates were 41, 38 and 28%, respectively, for the three groups (P < 0.001 for ranitidine vs. placebo, P = 0.274 for ranitidine vs. cimetidine). Ranitidine 75 mg was significantly more effective than placebo in providing overall heartburn relief (P < 0.001). The differences between the ranitidine and cimetidine groups were not significant, except for a greater reduction in heartburn frequency in the ranitidine group at the end of the study period (P < 0.05). Drug dose was lower and less rescue medication was used in the ranitidine group than the placebo group. The three treatment groups did not differ in terms of tolerability.

CONCLUSION

On-demand ranitidine 75 mg or cimetidine 200 mg are safe and effective treatment for reflux-related symptoms.

Inhibition of prostaglandin-induced intestinal secretion by igmesine in healthy volunteers

BACKGROUND & AIMS

Igmesine, a final sigma ligand, has been shown to inhibit intestinal secretion and diarrhea in animal models. The purpose of this study was to measure the inhibitory effect of igmesine on basal and prostaglandin E2 (PGE2)-induced jejunal secretion in normal volunteers.

METHODS

Jejunal absorption of water and electrolytes was measured with a three-lumen open-segment perfusion method in 16 volunteers. A double-blind crossover study was performed involving intraluminal infusion of PGE2 after oral administration of placebo or igmesine at two doses.

RESULTS

PGE2 induced net secretion of water and electrolytes (P < 0.01 vs. basal conditions). The effect of PGE2 on water and electrolytes was not changed by 25 mg of igmesine but was suppressed by 200 mg of igmesine. This effect lasted at least 3 hours after a single oral dose. Igmesine at a dose of 200 mg also produced a significant decrease in basal rates of water and electrolyte absorption.

CONCLUSIONS

Igmesine, a final sigma ligand, inhibits PGE2-induced intestinal secretion in normal humans. Evaluating the drug in chronic diarrheas may be of interest.

Total synthesis of brevetoxin A

Brevetoxin A is the most potent neurotoxin secreted by Gymnodinium breve Davis, a marine organism often associated with harmful algal blooms known as 'red tides'. The compound, whose mechanism of action involves binding to and opening of sodium channels, is sufficiently toxic to kill fish at concentrations of nanograms per ml and, after accumulation in filter-feeding shellfish, to poison human consumers. The precise pathway by which nature constructs brevetoxin A is at present unknown, but strategies for its total synthesis have been contemplated for some time. The synthetic challenge posed by brevetoxin A reflects the high complexity of its molecular structure: 10 oxygen atoms and a chain of 44 carbon atoms are woven into a polycyclic macromolecule that includes 10 rings (containing between 5 and 9 atoms) and 22 stereogenic centres. Particularly challenging are the 7-, 8- and 9-membered rings which allow the molecule to undergo slow conformational changes and force a 90 degrees twist at one of its rings. Here we describe the successful incorporation of methods that were specifically developed for the construction of these rings into an overall strategy for the total synthesis of brevetoxin A in its naturally occurring form. The convergent synthesis reported here renders this scarce neurotoxin synthetically available and, more importantly, allows the design and synthesis of analogues for further biochemical studies.

[Weight gain pattern in normal pregnant women]

OBJECTIVE

The purpose of this study was to determine the maternal weight gain pattern of normal pregnant women.

METHODS

One thousand five hundred and sixty-two (1,562) women, with 11,059 records, received prenatal care and had their babies delivered at the Second Hospital of West China University of Medical Sciences during the period of Jan. 1-Dec. 31, 1995. All the women without complications and with their babies weighted between 2,500-3,999 g were included, and data was analyzed.

RESULTS

The average age was 26.49 +/- 3.02 and height 158.69 +/- 4.85 cm. The women were divided into three categories according to their prepregnant body mass index (BMI): underweight (< 16.75), normal weight (16.75-23.71) and overweight (> 23.71). The BMIs of each categories increased as gestational week approached to the term, with total BMI increase as 8.07, 5.37, 3.82 for underweight, normal weight and overweight, respectively.

CONCLUSION

BMI, calculated with weight and height, is more accurate to assess maternal weight gain than weight alone do, and above results and accompanied charts could be used to monitor maternal weight gain as a reference.

[Molecular analysis of HLA-DR beta polymorphism in Han nationality patients with rheumatoid arthritis]

OBJECTIVE

To analyze the molecular basis for HLA-DR associations with rheumatoid arthritis(RA) in the han nationality of Chinese population.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were used to dertermine DRB1 alleles in 35 unrelated patients with RA and 100 healthy controls from the Han nationality.

RESULTS

The frequency of DR4(DRB1 * 04) was 51.4% in RA patients and 24.0% in the healthy controls(P < 0.01, RR = 3.3). There was a significant increase in the presence of the amino acid sequences QKRAA or QRRAA both in the RA patients overall compared with the healthy group(65.7% vs 30.0%, P < 0.001) and in DR4+ RA patients compared with DR4+ healthy individuals(100% vs 75.0%, P < 0.05). Substitution of residues in QKRAA, V85 and G86 appeared to correlate with relative risk for RA, among the subjects having 0-1 amino acid substitution, RA occurred in 48.8%, whereas in subjects with 2-3 amino acid changes, RA was present in only 16.7%.

CONCLUSION

These results suggest that DR4 is strongly associated with RA in the Han nationality, and the dominant effect that determines susceptibility to RA is associated with QKRAA or QRRAA as well as V85 and G86.

Immunohistochemical study of Fas antigen expression in synovial tissues from patients with rheumatoid arthritis

OBJECTIVE

To investigate the location and expression of Fas (Apo-1, CD-95) antigen in synovial tissue from rheumatoid arthritis (RA).

METHODS

Immunohistochemical technique was used to identify the location and expression of Fas antigen in synovial tissues from 27 RA, 11 osteoarthritis (OA), 7 ankloysing spondylitis (AS), 3 pigmented villo-hyperplastic synovitis, 1 juvenile rheumatoid (JRA) patients and 5 "normal" control subjects.

RESULTS

Fas was strongly expressed by synoviocytes and infiltrated lymphocytes in approximately two-thirds of RA patients (16/27). However, only weak expression occurred on lymphocytes in 3 of 11 OA, 1 of 7 AS patients and 1 of 5 "normal" subjects. The stain-positive substance in the forms of rings, granules, or dust was deposited on the cell membrane and in cytoplasm.

CONCLUSION

The expression of Fas may be involved in the mechanism of synovium proliferation and abnormal activation of local lymphocytes in RA.

[In vitro study on arsenic trioxide-inducing apoptosis in primary acute promyelocytic leukemie cells]

OBJECTIVE

To illustrate mechanisms of arsenic trioxide(As2O3) in the treatment of acute promyelocytic leukemia (APL).

METHODS

Cell-DNA content distribution, CD11b and CD33 antigens and nitroblue tetrazolium (NBT) reduction were evaluated in fresh APL cells from six APL patients treated in vitro with As2O3.

RESULTS

As2O3 had double effects on the cells inducing apoptosis and inducing partial differentiation at higher and at lower drug concentrations, respectively. As2O3 (0.1 approximately 2.0 micromol/L) could rapidly modulate and degrade APL-specific marker molecule PML-RARalpha protein, which could play an important role in the effects of As2O3 on APL cells.

CONCLUSION

As2O3 had double effects (induction of apoptosis and partial differentiation) on APL cells through the modulation and degradation of PML-RARalpha proteins.

Specific adaptation of gastric emptying to diets with differing protein content in the rat: is endogenous cholecystokinin implicated?

BACKGROUND

Recent studies indicate that gastric emptying may be influenced by patterns of previous nutrient intake. Endogenous cholecystokinin (CCK), whose synthesis and release can be affected by dietary intake, has a major role in the regulation of gastric emptying.

AIMS

To evaluate the influence of diets with differing protein content on gastric emptying of differing liquid test meals and plasma CCK levels in the rat and to check whether the inhibitory effect of exogenous CCK on gastric emptying is modified after long term intake of diets with differing protein content.

METHODS

Rats were fed for three weeks with high protein, medium protein (regular), or low protein diet. On day 22 gastric emptying of a peptone meal was studied. In addition, basal and postprandial CCK levels after the different dietary regimens were measured by bioassay. The time course of dietary adaptation was studied and its specificity assessed through the use of different (peptone, glucose, and methylcellulose) test meals. The effect of exogenous CCK-8 on gastric emptying was studied at the end of the adaptation period (three weeks).

RESULTS

Feeding the animals with a high protein diet for three weeks resulted in a significant (p < 0.05) acceleration (by 21.2 (8.2)%) of gastric emptying while feeding with a low protein diet was followed by a significant (p < 0.05) delay (by 24.0 (6.2)%) in the emptying rate. When the time course of the effect of dietary adaptation on gastric emptying was studied, it appeared that at least two weeks are required for dietary protein to be effective. The regulatory effect of dietary protein on gastric emptying proved to be dependent on meal composition. Only the emptying rate of a protein containing meal (40% peptone) was significantly modified by previous dietary intake. No significant (p > 0.05) changes were observed with glucose and methylcellulose meals whose emptying rates were similar in rats receiving a high protein or low protein diet. A peptone meal strongly and significantly (p < 0.05) increased plasma CCK levels in rats fed a medium protein (regular) diet. Results were similar in rats receiving a low protein diet (p < 0.05) but not in rats on a high protein diet (p > 0.05). As a consequence, postprandial plasma levels of CCK in rats fed with a medium or low protein diet were significantly (p < 0.05) higher than those in rats receiving a high protein diet. In rats on high and low protein diets, dose response curves to CCK-8 were virtually identical, suggesting that dietary protein intake has no influence on the effect of exogenous CCK.

CONCLUSIONS

These results clearly show that gastric emptying of a protein containing meal can be modified by previous dietary protein intake. This effect, which is time dependent and meal specific, may be related to changes in endogenous CCK release which will affect emptying rate. While the exact mechanisms underlying this adaptive response need to be studied and clarified further, these results emphasise the importance of dietary history in the evaluation and interpretation of gastric emptying data.

Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation

The voltage-gated delayed-rectifier-type K+ channel Kv2.1 is expressed in high-density clusters on the soma and proximal dendrites of mammalian central neurons; thus, dynamic regulation of Kv2.1 would be predicted to have an impact on dendritic excitability. Rat brain Kv2.1 polypeptides are phosphorylated extensively, leading to a dramatically increased molecular mass on sodium dodecyl sulfate gels. Phosphoamino acid analysis of Kv2.1 expressed in transfected cells and labeled in vivo with 32P shows that phosphorylation was restricted to serine residues and that a truncation mutant, DeltaC318, which lacks the last 318 amino acids in the cytoplasmic carboxyl terminus, was phosphorylated to a much lesser degree than was wild-type Kv2.1. Whole-cell patch-clamp studies showed that the voltage-dependence of activation of DeltaC318 was shifted to more negative membrane potentials than Kv2.1 without differences in macroscopic kinetics; however, the differences in the voltage-dependence of activation between Kv2.1 and DeltaC318 were eliminated by in vivo intracellular application of alkaline phosphatase, suggesting that these differences were due to differential phosphorylation. Similar analyses of other truncation and point mutants indicated that the phosphorylation sites responsible for the observed differences in voltage-dependent activation lie between amino acids 667 and 853 near the distal end of the Kv2.1 carboxyl terminus. Together, these parallel biochemical and electrophysiological results provide direct evidence that the voltage-dependent activation of the delayed-rectifier K+ channel Kv2. 1 can be modulated by direct phosphorylation of the channel protein; such modulation of Kv2.1 could dynamically regulate dendritic excitability.

Isolation of new bioactive annonaceous acetogenins from Rollinia mucosa guided by liquid chromatography/mass spectrometry

Reversed-phase high-performance liquid chromatography (RP-HPLC) fractionation, monitored by liquid chromatography/electrospray mass spectrometry (LC/ESI-MS), led to the isolation of two new bioactive annonaceous acetogenins, rollidecin C (1) and rollidecin D (2), from the bioactive aqueous methanol fraction of the leaves of Rollinia mucosa (Annonaceae). The structures were confirmed by analyses of the 1H and 13C NMR data. In addition, a known adjacent bis-tetrahydrofuran (THF) acetogenin, desacetyluvaricin (3), was isolated from this plant for the first time utilizing the LC/ESI-MS monitoring approach. Compound 1 exhibited selective cytotoxicity toward the colon tumor cell line (HT-29), while 2 showed only borderline cytotoxicity in a panel of six human tumor cell lines.

[Spinal segment distribution of neural innervation related houhai acupoint--studied by CB-HRP tracing method focused on observation of the dendrites of spinal motor neurons]

The spinal segment distribution of neural innervation related Houhai acupoint in rats has been investigted by using horseradish peroxidase conjugated cholera toxin B subunit (CB-HRP) tracing technique. Spinal motoneurons (Mn) in L6-S1 were labeled retrogradely by CB-HRP, and their features have been characterized: 1) their marginal plexus of the dendrites radially projected to the lateral and/or anterior funiculus and their distal portions forming subpial dendritic plexus; 2) the medial dendrites ran along the ventral margin of the gray commissure and their distal portions surrounded the central canal' forming a subependymal dendritic plexus. Both of them are Golgi-phobic. Some distal branches of dendrites penetrated to the contralateral gray matter. The dendritic arbors of the labeled motoneurons in the group of electro-acupuncture or group of acupoint-inoculation with sheep red blood cells contracted in comparison with that in the normal control group. The primary sensory transganglionic labeled fibers and preterminal fibers revealed by CB-HRP in the dorsal horn and dorsal commissural nucleus of the spinal cord (L5-S2) converged and overlaped with the dendrites of retrogradely labeled motoneurons. The results indicated there is a reflect circuit of afferent-integration-efferent neuro-network in the spinal cord related Houhai acupoint. The Mns retrogradely labeled by CB-HRP in the L6-S1 segments might be involved in Houhai acupuncture.

The FHIT gene is alternatively spliced in normal kidney and renal cell carcinoma

FHIT (Fragile Histidine Triad), a putative tumor suppressor gene, was cloned from fetal brain and colon cDNA libraries. Portions of this gene are deleted in esophageal, colon, lung and breast tumors, but this gene has not been found altered in sporadic renal cell carcinomas. We report here an alternatively spliced form of this gene cloned from a kidney cDNA library. This cDNA is 1189 bp in length, and contains an additional 94 bp exon, designated exon 2a (E2a). This novel sequence is located between exon 2 and exon 3 of the FHIT gene's untranslated region and exon 2a is present in all normal kidney tissues and cell lines. Analyses performed on sporadic renal cell carcinoma (RCC) tissues and cell lines, show consistent loss of exon 8 of the FHIT cDNA in almost 60% of the cases. Interestingly, in a familial, as well as, in a metastatic RCC, derived from a patient with the sporadic form, exon 2a and exon 3 are also deleted. Northern analyses with the exon 2a of the familial and the metastatic RCC demonstrates concurrent loss of expression of a 4.4 kb transcript with the loss of the E2a sequence, suggesting that exon 2a of the FHIT gene may play an important role in the oncogenesis of renal cell carcinoma.

[Double effects of arsenic trioxide (As2O3) on acute promyelocytic leukemic cell line]

OBJECTIVE

To investigate the effects of a wide range of concentrations of As2O3 on NB4 cells.

METHODS

Cell morphology, cell-DNA content distribution, CD11b and CD33 antigens and nitroblue tetrazolium (NBT) reductions were evaluated in an APL cell line NB4 cells with or without As2O3 treatment. In addition, immunofluorescent analysis for APL marker molecule PML-RAR alpha was also performed.

RESULTS

1-2 mumol/L of As2O3 treated NB4 cells presented morphologically some features of apoptotic cells such as intact cell membrane, chromatin condensation and nuclear fragmentation. Sub-G1 cells, whose percentage presents concentration and time-dependency, were observed by flow cytometer. Otherwise, NB4 cells with the treatment of As2O3 at 0.1-0.25 mumol/L for a long time (10 days) have differentiation-related morphology, and their differentiation antigens CD11b and CD33 were also modulated to some extent. In addition, 0.1-2 mumol/L of As2O3 could rapidly and effectively modulate and degradate PML/PML-RAR alpha proteins.

CONCLUSION

As2O3 had double effects (induction of apoptosis and imcomplete differentiation) on NB4 cells, which could associate with rapid modulation and degradation of PML/PML-RAR alpha proteins.

Chromosomal abnormality inv(3)(q21q26) associated with multilineage hematopoietic progenitor cells in hematopoietic malignancies

We have identified ten patients with acute myeloid leukemia (AML) and one patient with chronic myeloid leukemia with megakaryocytic crisis who displayed an inv(3)(q21q26). Seven of them had an additional monosomy 7. Most of them had a myelodysplastic syndrome (MDS) preceding AML, normal or increased platelet counts, increased number of megakaryocyte, megakaryocytic dysplasia, and erythroid dysplasia. There was a high incidence of resistance to induction chemotherapy, short remission time, and early relapse. Seven patients were immunologically analyzed. The main immunophenotypes were as follow: CD7+, CD34+, HLA-DR+, CD38+, CD13+, CD33+, CDw65+, CD2-, CD3-, CD4-, CD8-, CD19+, CD20-, CD11b-. Our results suggest that the leukemia with inv(3)(q21q26) represents a new cytogenetic-clinicopathologic subtype, characterized by 1) abnormal megakaryopoiesis and multiple hematopoietic lineage involvement; 2) an antecedent MDS; 3) poor response to conventional chemotherapy; and 4) expression of CD7, CD34, CD38, HLA-DR, CD13, and CD33 antigens. We propose that the malignant transformation in patients with inv(3)(q21q26) occurs in an early stem cell prior to lineage commitment.

Reinterpretation of G-banded complex karyotypes by fluorescence in situ hybridization with chromosome-specific DNA painting probes and alpha-satellite centromere-specific DNA probes in malignant hematological disorders

In this study, we have performed fluorescence in situ hybridization (FISH) with chromosome-specific DNA painting probes 1, 2, 3, 4, 6, 8, and 12 and centromere-specific DNA probes 7,10,12,17,18, and X after G-banding on the same metaphase spreads from four patients with malignant hematological disorders to more precisely interpret their complex karyotypes. The findings demonstrated that the application of combined G-banding and FISH can more accurately explain complex karyotypes of hematological malignancies. FISH can detect not only the origin of marker chromosomes, but also the complex rearrangements that cannot be identified by routine banding techniques. This approach is very important to complement the cytogenetic analysis of malignant disorders and to evaluate the role of chromosome change in the development, progression, and prognosis of tumors.

Bioactive annonaceous acetogenins from Rollinia mucosa

Two new bioactive Annonaceous acetogenins, rollitacin (1) and rollinacin (2), along with one known acetogenin, javoricin, were isolated from the ethanolic extract of the leaves of Rollinia mucosa. Compounds 1 and 2 exhibited selective inhibitory effects among six human solid tumour cell lines. The structural elucidations of 1 and 2 were achieved by various spectroscopic analyses and chemical derivatizations.

Konishiol, a new sesquiterpene, and bioactive components from Cunninghamia konishii

Three sesquiterpenes, konishiol (1), cadalenol (2), 3-cedranol (3), one diterpene, manool (4), and one lignan, (+)-tsugacetal (5), have been isolated, for the first time, from the whole plant of Cunninghamia konishii by using bioactivity-directed fractionation. Compound 1 is new to the literature, and its chemical structure was determined by various spectroscopic analyses including EIMS, HREIMS, NOE, NOESY, and by preparing its di-acetyl derivative (1a). Compounds 2-5 showed moderate to weak bioactivities in brine shrimp (BST) and mosquito larvae (YFM) bioassays as well as cytotoxicities against three human solid tumor cell lines.

[DNA typing for HLA-DR and HLA-DQ alleles in Chinese patients with rheumatoid arthritis]

We analysed the associations of DR and DQ alleles with rheumatoid arthritis (RA) in Han nationality of China. PCR-RFLP technique was used to determine DRB1, DQA1 and DQB1 alleles in 35 unrelated patients with RA and 100 healthy controls from the Hans. The frequency of DR4 was 51.4% in RA patients and 24.0% in the healthy controls (P < 0.01, RR = 3.30). Subtyping of DR4 revealed no differences in the relative distributions of the DR4 alleles between the RA group and the controls, which both were predominated by DRB1 * 0405 allele, but there was a significant increase in the absolute frequency of DRB1 * 0405 in RA patients compared with the healthy controls (31.4% vs 12.0%, P < 0.01). DQ4 (DQB1 * 04) was also increased both in the RA patients compared with the healthy controls (37.1% vs 10.0%, P < 0.001) and in DR4+ RA patients compared with DR4+ healthy ones (72.2% vs 41.6%, P = 0.0376). Further analysis showed that the haplotype DR4-DQ4 was associated with RA (RR = 5.17, P < 0.001), and that the DR4(+)-DQ4+ patients had more severe disease than the DR4- patients. These results suggest that DR4, mainly the DRB1 * 0405, is associated with RA in Han nationality, and DQ4 may play a role in DR4 conferring susceptibility to RA. The DR4-DQ4 haplotype could be taken as a predictive marker for disease severity.

Screening for Annonaceous acetogenins in bioactive plant extracts by liquid chromatography/mass spectrometry

The Annonaceous acetogenins are amenable to analysis by liquid chromatography/mass spectrometry (LC/MS) using the electrospray positive-ion mode. Under conditions of atmospheric pressure in-source collision-induced dissociation (APICID), the acetogenins reproducibly provided characteristic ion patterns and fragment ions. Accordingly, the presence of these biologically interesting acetogenins and other derivatives in plant extracts and chromatographic fractions can be readily detected by analyzing selected ion chromatograms. LC/MS screening of a bioactive crude methanol-soluble fraction of Rollinia mucosa detected the presence of some 40 known acetogenins in this plant extract, in addition to four new acetogenins of diverse structure. This rapid and relatively uncomplicated selected ionization procedure should also prove suitable for the screening of many other structural families of natural products.

Additional bioactive annonaceous acetogenins from Asimina triloba (Annonaceae)

Trilobalicin (1), a new nonadjacent bis-THF ring annonaceous acetogenin, 2,4-cis- (2) and 2,4-trans-trilobacinone (3), the ketolactones of trilobacin, an adjacent bis-THF ring acetogenin, were isolated from the stem bark of Asimina triloba (L.) Dunal (Annonaceae). Their structures were established based on chemical and spectral evidence. The relative stereochemistry of 1 was determined as trans/threo/threo/trans/erythro from C-10 to C-22 by comparisons of NMR data with those of model compounds. Compound 1 is the first example of a nonadjacent bis-THF acetogenin being isolated from the title species and represents a new type of these compounds. Bioactivities of these new structures against brine shrimp larvae and six human solid tumor cell lines were determined, and cytotoxic selectivities were shown for the lung (A-549) and breast (MCF-7) cell lines with up to a million times the potency of adriamycin.

[Comparison between magnetic resonance imaging and CT in detection and localization of non-magnetic intraocular foreign bodies]

OBJECTIVE

To approach the characteristics of magnetic resonance imaging (MRI) and CT in detection and localization of intraocular foreign bodies.

METHODS

Detection and localization of 28 cases (42 foreign bodies) of non-magnetic intraocular foreign body were compared in MRI and CT with criteria of operative results.

RESULTS

The positive rates of MRI and CT in detection of 42 non-magnetic intraocular foreign bodies were respectively 90.5% and 95.2% (chi 2 test: P > 0.5). The positive rates of MRI and CT in localization were respectively 89.5% and 60.0% (chi 2 test: P < 0.05).

CONCLUSION

MRI could be used in detection and localization of non-magnetic intraocular foreign bodies with high positive rates in detection and superior to CT in demonstrating non-magnetic intraocular foreign bodies with low density and the relationship between foreign bodies and intraocular tissues. MRI was not as believable as CT in detection of foreign bodies in eye wall and not an appropriate modality in examinations of magnetic intraocular foreign body.

Bioactive compounds from Taiwania cryptomerioides

Two new sesquiterpenes, 10 alpha-hydroxyamorphan-4-en-3-one (1) and 4 alpha-methylcadinane-4 alpha-methyl-1 alpha,2 alpha,10 alpha-triol (2), together with four known compounds, sesquiterpenes 10 alpha-hydroxycadinan-4-en-3-one (3) and alpha-cadinol (4), diterpene ferruginol and lignan helioxanthin, were isolated from the whole plant of Taiwania cryptomerioides under bioassay-guided fractionations. The structures of 1 and 2 were elucidated mainly by the NMR spectroscopic analyses. Bioactivities of the isolated compounds against brine shrimp, yellow fever mosquito larvae, and human tumor cells are reported; compound 4 was the most bioactive, showing selectivity for the human colon tumor cell line (HT-29).

[Studies on distribution patterns of modulator CGRP in different motoneuron pools in rats]

Using retrograde labelling combined with calcitonin gene-related peptide (CGRP) immunocytochemistry technique, distribution patterns of the content of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) were studied in two different motoneuron (Mn) pools supplying soleus (SOL, slow-twitch muscle) and extensor digitorium longus (EDL, fast-twitch muscle) of hindlimbs in rats during development. The Mn pools were identified with a novel retrograde tracer, choleragen B subunit (CB) coupled with colloidal gold (CB-Au, 5 nm particle, prepared by ourselves), which was injected into EDL or SOL. After the silver intensification for visualizing colloidal gold particles, CGRP immunocytochemistry were processed. The CB-Au retrogradely identified Mns in each Mn pool were counted and CGRP-LI intensity of Mns was evaluated as strong, moderate, weak and negative. The double labelling revealed different distribution patterns of CGRP-LI content between SOL and EDL Mn pools during development. Comparing the level of CGRP expression between the two Mn pools, SOL Mn pool had a higher ratio of neurons lacking CGRP-LI/weak CGRP LI and a lower proportion of strongly CGRP-LI labelled ones. These results suggest that the difference in content of CGRP-LI in Mns is related to the type of muscular motor activity.

Three new adjacent bis-tetrahydrofuran acetogenins with four hydroxyl groups from Asimina triloba

Three new adjacent bis-tetrahydrofuran ring Annonaceous acetogenins with four hydroxy groups, bullatetrocin (1), 10-hydroxyasimicin (2), and 10-hydroxytrilobacin (3), were isolated by activity-directed fractionation from the stem bark of Asimina triloba. Their structures were established on the basis of chemical and spectral evidence. The absolute stereochemistry at the C-10 hydroxy position was determined by converting 2 and 3 to their ketolactone isomers, 2,4-cis/trans 10-hydroxyasimicinones and 2,4-cis/trans 10-hydroxytrilobacinones, respectively. The bioactivities of the new compounds against brine shrimp larvae and six human solid-tumor cell lines are reported, and structure-activity relationships between trihydroxylated and tetrahydroxylated acetogenins are discussed. In addition to 1-3, gigantetrocin A, 2,4-cis/trans-gigantetrocin A-ones, annonacin, and annonacin A were also isolated for the first time from this species.

Chlorinated annonaceous acetogenins and their bioactivities

4(S)-Chloro-4-deoxygigantetrocin A and 4(S), 18-dichloro-4,18-dideoxyasimilobin were obtained by treating gigantetrocin A with triphenylphosphine and CCl4. The structures were determined by spectroscopic methods. The chlorinated compounds show decreased bioactivities in the brine shrimp lethality test and against human tumor cell lines.