[Determination of benzene, toluene and xylene in marine sediment samples by micellar electrokinetic capillary chromatography]

The analysis and determination of the contents of benzene series compounds in marine sediment are important in chemical exploration of petroleum resources. In the present study a method has been developed for this purpose by using micellar electrokinetic capillary chromatography (MECC). A fused silica capillary of 45 cm x 75 microns i.d. (effective length 40 cm) was used. Running buffer was 2 mmol/L aqueous solution of sodium tetraborate containing 75 mmol/L sodium dodecyl sulfate (pH 9.16) and 20% methanol. The applied voltage was 25 kV and detection wavelength was 200 nm. The benzene, toluene and xylene were separated well within 20 min. Peak area was used for quantitative analysis. The calibration curves were linear in the range 4-50 mg/L. The relative standard deviation was within 6.2%. The contents of benzene series in sediments were between 3.79 and 17.36 micrograms/g.

Tissue-specific regulation of vein/EGF receptor signaling in Drosophila

Signaling by the Drosophila EGF receptor (DER) is modulated by four known EGF-like proteins: the agonists Vein (Vn), Spitz (Spi), and Gurken (Grk) and the antagonist Argos (Aos). DER is broadly expressed and thus tissue-specific regulation of ligand expression and activity is an important mechanism for controlling signaling. Here we investigate the tissue-specific regulation of Vn signaling by examining vn transcriptional control and Vn target gene activation in the embryo and the wing. The results show a complex temporal and spatial regulation of vn transcription involving multiple signaling pathways and tissue-specific activation of Vn target genes. In the embryo, vn is a target of Spi/DER signaling mediated by the ETS transcription factor PointedP1 (PntP1). This establishes a positive feedback loop in addition to the negative feedback loop involving Aos. The simultaneous production of Vn provides a mechanism for dampening Aos inhibition and thus fine-tunes signaling. In the larval wing pouch, vn is not a target of Spi/DER signaling but is expressed along the anterior-posterior boundary in response to Hedgehog (Hh) signaling. Repression by Wingless (Wg) signaling further refines the vn expression pattern by causing a discontinuity at the dorsal-ventral boundary. The potential for vn to activate DER target genes correlates with its roles in development: vn has a minor role in embryogenesis and does not induce DER target genes such as aos and pntP1 in the embryo. Conversely, vn has a major role in wing development and Vn/DER signaling is a potent inducer of DER target genes in the wing disc. Spi also has the potential to induce DER target genes in the wing disc. However, the ligands appear to evoke specific responses that result in different patterns of target gene expression. Finally, we show that other factors modulate the potential of Vn so that induction of Vn/DER target genes in the wing pouch is cell specific.

Interlaboratory comparison of ultrasonic backscatter, attenuation, and speed measurements

In a study involving 10 different sites, independent results of measurements of ultrasonic properties on equivalent tissue-mimicking samples are reported and compared. The properties measured were propagation speed, attenuation coefficients, and backscatter coefficients. Reasonably good agreement exists for attenuation coefficients, but less satisfactory results were found for propagation speeds. As anticipated, agreement was not impressive in the case of backscatter coefficients. Results for four sites agreed rather well in both absolute values and frequency dependence, and results from other sites were lower by as much as an order of magnitude. The study is valuable for laboratories doing quantitative studies.

[Analysis of 50 cases of sexual dysfunction]

Fifty cases of male sexual dysfunction were analyzed in order to investigate the incidence and causes of the erectile dysfunction in the different injuries. The results showed that the incidence of erectile dysfunction of the patients with brevic fracture and urethra injury is 62.50%, main caused by the damage of pudendal nervous and arterial system. The incidence in the patients with the spinal fracture and light spinal cord injury is 50%, caused by the damage of nervous system. The erection in the 17 cases of the patients with only one testis injury is normal. Two cases with bilateral testis injury have suffered from erectile dysfunction.

Expression of cyclooxygenase-2 in rat vascular smooth muscle cells is unrelated to nuclear factor-kappaB activation

The promoter region of cyclooxygenase-2 (COX-2) gene contains binding sites for a number of important transcription factors including cyclic AMP response element, nuclear factor-IL6, nuclear factor-kappaB (NF-kappaB) and TGF-beta response element. Several reports have documented that the activation of NF-kappaB triggers the expression of COX-2 gene. In the present study, NF-kappaB was activated by TNF-alpha in rat aortic smooth muscle cells as demonstrated by electrophoretic mobility shift assay. The activity of NF-kappaB induced by TNF-alpha was blocked by calpain inhibitor I, a potent NF-kappaB inhibitor. However, the activation of NF-kappaB was not related to the expression of COX-2 induced by TNF-alpha since calpain inhibitor I blocked the activation of NF-kappaB but not the expression of COX-2 mRNA or protein. Mutation of rat COX-2 NF-kappaB-like sites in the promoter region did not significantly reduce the promoter activity. These results suggest that the transcriptional regulation of COX-2 expression by NF-kappaB depends upon the types of cells studied and that activation of this transcription factor alone does not play an important role in the expression of COX-2 in rat smooth muscle cells.

1Alpha,25-dihydroxyvitamin D3 up-regulates Bcl-2 expression and protects normal human thyrocytes from programmed cell death

Apoptosis is thought to play an important role in the pathogenesis of autoimmune thyroid disease. 1alpha,25-dihydroxyvitamin D3 (VD3) has been shown to suppress several autoimmune diseases. However, the mechanism by which VD3 has these effects is not known. We evaluated the alterations in apoptosis, induced by VD3. Thyrocytes were treated with VD3, and the expression of the Bcl-2 family molecules was studied at both the messenger RNA and protein levels. It was found that VD3 significantly induced the expression of Bcl-2 messenger RNA and protein in thyrocytes but had no effect on the expression of Bcl-xl and Bax. The increase in Bcl-2 expression, mediated by VD3, correlated with protection of thyrocytes against the induction of apoptosis by either staurosporine or UV irradiation. VD3-induced increases in the expression of Bcl-2 could be mimicked by VD3 analogs with high nuclear receptor affinity, but not by analogs only with nongenomic actions. These data indicate a role for Bcl-2 in the regulation of apoptosis in thyrocytes and raise the possibility that VD3 or its agonists may have therapeutic benefit in thyroid disorders.

Abnormal clavicles in a neonate with partial monosomy 21

We report a newborn with partial monosomy 21, whose skeletal survey revealed strikingly abnormal clavicles.

Considerations in reference values for nerve conduction studies

Despite the universal application of reference values, understanding their production and underlying limitations is often overlooked. Without a deeper consideration for this issue, opportunities for treatment may be missed or misdiagnosis may occur. This article reviews relevant biostatistical issues in the generation of reference intervals and subsequent errors that may occur. Further discussion includes recommendations on how to correct statistical errors, as well as more recent methods for distinguishing between "healthy" and "diseased."

Does famotidine have similar efficacy to misoprostol in the treatment of non-steroidal anti-inflammatory drug-induced gastropathy?

The study aimed to evaluate the efficacy of famotidine, an H2 receptor blocker, and misoprostol, a prostaglandin E analogue, in the treatment of non-steroidal anti-inflammatory drug-induced (NSAID) gastropathy in arthritic patients. A total of 128 patients receiving piroxicam, sulindac, indomethacin, naproxen, tolmetin and aspirin were enrolled in the study. Gastroscopic examination was performed at the beginning and after eight weeks of randomised famotidine or misoprostol treatment. A standard scoring method for gastroscopic finding was applied. Forty-four patients with scores 1-3 were classified as group A; while the other 84 with score 4 (ulcer) were placed in group B. In group A, 26 received famotidine and 18 misoprostol. In group B, 36 received famotidine and 48 misoprostol. Biopsy specimens taken from the rim of the ulcer with adjacent normal mucosa were coded and tested for Helicobacter pylori. In group A, all but two patients taking famotidine recovered from NSAID gastropathy, and there was no statistical significance between the two drugs. In group B, all but four patients receiving famotidine improved and there was no statistical significance between the two subgroups for complete healing rate. The prevalence of H. pylori was 36.9%, lower than that in the general population. It was concluded that famotidine and misoprostol have similar efficacy in the treatment of NSAID gastropathy.

[Inhibition of signal transduction pathways of endothelin-1-induced proliferation of vascular smooth muscle cells by nitric oxide]

The signal transduction pathways of the inhibitory effect of nitric oxide (NO) on endothelin (ET)-induced proliferation of vascular smooth muscle cells (VSMCs) were studied. 3H-thymidine (TdR) incorporation, mitogen-activated protein kinase (MAPK) activity and protein kinase C (PKC) activity of cultured VSMCs of rabbits thoracic aorta were measured in the presence of either NO precursor L-arginine (L-Arg) or NO donor 3-morpholino sydnonimine-hydrochloride (SIN-1), or ET-1 alone or with L-Arg or SIN-1. The results show: (1) ET-1 (10(-8) mol/L) significantly increased VSMCs 3H-TdR incorporation (5 times, P < 0.01), MAPK activity (4 times, P < 0.01) and PKC activity (3 times, P < 0.01), as compared with control. L-Arg or SIN-1 alone was without effect on 3H-TdR incorporation, MAPK activity and PKC activity. (2) When ET-1 and L-Arg (2, 5, 10 mmol/L) were simultaneously administered, 3H-TdR incorporation and activity of both MAPK and PKC were all significantly decreased in comparison with the ET group. (3) When ET-1 + SIN-1 (5, 10, 50 mumol/L), the effects coincide with those of the ET-1 + L-Arg groups. These findings indicate that NO inhibition of the signal transduction pathways of the ET-1-induced proliferation of VSMCs may be mediated by the inhibition of ET-1-induced activation of both PKC and MAPK.

Induction of thyroiditis in mice with thyrotropin receptor lacking serologically dominant regions

Grave's disease (GD) is characterized by pathogenic autoantibodies to the human thyrotropin receptor (hTSH-R), and is frequently associated with a lymphocytic infiltrate of the thyroid gland. In attempts to establish a murine model of GD, we and others have previously shown that immunization of mice with recombinant preparations of the hTSH-R ectodomain induces high titres of specific antibodies, which, however, are not pathogenic, nor is the response accompanied by the development of thyroiditis. Since earlier reports identified the serological immunodominant determinants within the N- and C-terminal regions of hTSH-R ectodomain, we reasoned that immunization of mice with truncated fragments of ectodomain lacking these dominant regions might result in skewing of the response to other determinants of the molecule, with consequent induction of immunopathological features present in GD. We show here that multiple challenge of BALB/c mice with an amino acid fragment of residues 43-282 generates antibodies directed at hTSH-R peptides 37-56, 157-176, 217-236 and 232-251. This reactivity pattern is distinct from that induced previously with the whole ectodomain of hTSH-R in BALB/c animals. Thyroid function remained unaffected in these mice, suggesting that pathogenic antibodies were not being induced. Interestingly, some animals developed lymphocytic infiltration of the thyroid gland, clearly indicating the presence of pathogenic T cell determinants within the 43-282 fragment. Challenge with the related fragment 43-316 produced the same pattern of serological response to the synthetic peptides as fragment 43 282, but was not accompanied by thyroiditis. The results demonstrate: (i) the presence of thyroiditogenic determinants within hTSH-R, and (ii) that these pathogenic determinants are likely to be cryptic, as their effect is exhibited only when the hierarchy of immunodominance within hTSH-R is drastically altered.

Influence of SCH23390 and spiperone on the expression of conditioned place preference induced by d-amphetamine or cocaine in the rat

The present study investigated the effects of selective dopamine D1 and D2 receptor antagonists, SCH23390 and spiperone, on the expression of conditioned place preference (CPP) induced by either d-amphetamine or cocaine. The CPP protocol consisted of three phases: pre-conditioning exploration, conditioning, and a post-conditioning test. The data indicated that CPP was significantly induced by intraperitoneal injection of either d-amphetamine (2 mg/kg) or cocaine (10 mg/kg). The expression of d-amphetamine CPP was significantly inhibited by SCH23390 (0.08, 0.16 mg/kg) and spiperone (0.15 mg/kg) when given alone before the post-conditioning test session. In contrast, such pretreatment to produce antagonistic effects was not observed for cocaine CPP. However, the expression of cocaine CPP was significantly attenuated by a combination of SCH23390 and spiperone administered prior to the test session. These data indicate that the rewarding properties of d-amphetamine and cocaine as expressed under the CPP task may depend upon different neural substrates. The degrees of D1 and D2 receptors involved in mediating the expression of CPP induced by d-amphetamine and cocaine are different.

Long-term continuous infusion of propofol as a means of sedation for patients in intensive care unit: relationship between dosage and serum concentration

BACKGROUND

We studied the effect of long-term continuous propofol infusion in patients who were utilizing mechanical ventilation in intensive care unit. The purpose of our study was to identify the appropriate dosage of propofol and to monitor the relating serum level that would provide satisfactory sedative and hypnotic effects to the patients, i.e., to procure a Ramsay Sedation Scale (RSS) value between 2 and 3.

METHODS

Ten mechanically ventilated ICU patients were studied. The syringe pump was set to deliver propofol at a rate of 1 mg/kg/h without an initial loading dose. After continuous infusion of propofol for 24 h, in each patient 5 ml of whole blood was sampled daily for one week. All samples were analyzed for serum level of propofol by high performance liquid chromatography.

RESULTS

When the Ramsay Sedation Scale (RSS) value was between 2 and 3, the mean dosage of infused propofol was 0.71 +/- 0.31 mg/kg/h (ranging from 0.58 to 1.27 mg/kg/h) and the mean plasma concentration was 0.58 +/- 0.22 microgram/ml (ranging from 0.20 to 0.86 microgram/ml). The lipid serum level was measured in three patients whose infusion duration was greater than 14 days. The respective level was 321 mg/dl, 139 mg/dl, and 99 mg/dl. The first patient died from multiple organ failure as a result of multiple trauma. Four patients simultaneously received infusion of propofol and muscle relaxant.

CONCLUSIONS

We concluded that propofol infusion given at a rate of 0.71 +/- 0.31 mg/kg/h and a plasma concentration level of less than 1 microgram/ml would be sufficient to produce a sedation with RSS value between 2 and 3.

Negative regulation of IS2 transposition by the cyclic AMP (cAMP)-cAMP receptor protein complex

Three sequences similar to that of the consensus binding sequence of the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex were found in the major IS2 promoter region. Experiments were performed to determine whether the cAMP-CRP complex plays a role in the regulation of IS2 transposition. In the gel retardation assay, the cAMP-CRP complex was found to be able to bind the major IS2 promoter. A DNA footprinting assay confirmed that the cAMP-CRP complex binds to the sequences mentioned above. With an IS2 promoter-luciferase gene fusion construct, the cAMP-CRP complex was shown to inhibit transcription from the major IS2 promoter. IS2 was found to transpose at a frequency approximately 200-fold higher in an Escherichia coli host defective for CRP or adenyl cyclase than in a wild-type host. These results suggest that the cAMP-CRP complex is a negative regulator of IS2 transposition.

Effects of capsaicin on human nasal mucosa

In order to determine the effects of capsaicin on the sympathetic innervation of human nasal mucosa, the effects of capsaicin on the contractile response of isolated human nasal mucosal blood vessels to field stimulation and methoxamine were investigated. Results showed that capsaicin enhanced field stimulation but there were no effects on mucosal contraction induced by methoxamine. Likewise, the drug had no effects on mucosal basal tension but potentiated mucosal contractions by norepinephrine. The study indicated that capsaicin may increase sympathetic function with the potentiating effects of norepinephrine. Because no effects of capsaicin on the resting tension of the nasal mucosa in vitro were noted, it is therefore deduced that local reactions in nasal mucosa by capsaicin in vivo should be via central or local reflexes.

Mini-proinsulin and mini-IGF-I: homologous protein sequences encoding non-homologous structures

Protein minimization highlights essential determinants of structure and function. Minimal models of proinsulin and insulin-like growth factor I contain homologous A and B domains as single-chain analogues. Such models (designated mini-proinsulin and mini-IGF-I) have attracted wide interest due to their native foldability but complete absence of biological activity. The crystal structure of mini-proinsulin, determined as a T3R3 hexamer, is similar to that of the native insulin hexamer. Here, we describe the solution structure of a monomeric mini-proinsulin under physiologic conditions and compare this structure to that of the corresponding two-chain analogue. The two proteins each contain substitutions in the B-chain (HisB10-->Asp and ProB28-->Asp) designed to destabilize self-association by electrostatic repulsion; the proteins differ by the presence or absence of a peptide bond between LysB29 and GlyA1. The structures are essentially identical, resembling in each case the T-state crystallographic protomer. Differences are observed near the site of cross-linking: the adjoining A1-A8 alpha-helix (variable among crystal structures) is less well-ordered in mini-proinsulin than in the two-chain variant. The single-chain analogue is not completely inactive: its affinity for the insulin receptor is 1500-fold lower than that of the two-chain analogue. Moreover, at saturating concentrations mini-proinsulin retains the ability to stimulate lipogenesis in adipocytes (native biological potency). These results suggest that a change in the conformation of insulin, as tethered by the B29-A1 peptide bond, optimizes affinity but is not integral to the mechanism of transmembrane signaling. Surprisingly, the tertiary structure of mini-proinsulin differs from that of mini-IGF-I (main-chain rms deviation 4.5 A) despite strict conservation of non-polar residues in their respective hydrophobic cores (side-chain rms deviation 4.9 A). Three-dimensional profile scores suggest that the two structures each provide acceptable templates for threading of insulin-like sequences. Mini-proinsulin and mini-IGF-I thus provide examples of homologous protein sequences encoding non-homologous structures.

U-insertion/deletion Edited Sequence Database

Uridine insertion/deletion RNA editing is a post-transcriptional RNA modification occurring in the mitochondria of kinetoplastid protozoa. The U-insertion/deletion Edited Sequence Database is a compilation of mitochondrial genes and edited mRNAs from five kinetoplastid species. It contains separate files with the DNA, mRNA (both unedited and edited) and predicted protein sequences, as well as alignments of the Leishmania tarentolae and Trypanosoma brucei protein sequences from edited and unedited genes. The sequence files are in GCG format. A 'map' sequence file showing the location of U-deletions, U-insertions and the translated amino acid sequences is also provided for each gene. Genomic maps for each species are also provided with clickable genes, including maxicircle-encoded gRNAs. Sets of aligned nuclear rRNA sequences from kinetoplastid protozoa are also provided, which were used for phylogenetic reconstructions in an analysis of the origin of RNA editing. The database is available through the World Wide Web as an HTML document at the URLhttp://www.lifesci.ucla.edu/RNA/trypanosome/ database.html

Cloning of porcine neuron growth inhibitory factor (metallothionein III) cDNA and expression of the gene in Saccharomyces cerevisiae

Growth inhibitory factor (GIF), a member of the metallothionein (MT) family, is also known as MTIII. This protein distinguishes itself from other MT isoforms by exerting an inhibitory effect on cortical neuron growth instead of metal ion buffering. In this work, we cloned MTIII genes from a porcine brain cDNA library. Two species of clones were isolated that vary with respect to one nt in the coding sequence. This discrepancy results in the translation of two MTIII primary structures having a different amino acid at residue 46. Herein, both MTIII cDNAs were constructed into an expression vector and transformed into yeast cells, respectively. The yeast carrying either MTIII gene displayed a similar metal tolerance when cultured in a medium containing metal. The resistance to metal toxicity was attributed to the expression of MTIII gene which was confirmed by RNA and protein analyses. The characteristics of the protein stability, metal binding affinity and ultraviolet absorption spectrum of the yeast produced MTIII are also compared with those of MTII. The comparison reveals that both MTs have similar physical characteristics. Moreover, circular dichroism spectrum of Cd saturated MTIII was analyzed as well. Typical Cys-Cd bands for MTII appear in the spectrum, indicating similar metal-thiol interactions for MTIII to those for other MT isoforms.

Effect on infant mortality of iodination of irrigation water in a severely iodine-deficient area of China

BACKGROUND

Hotien county in Xinjiang province, China, is an area of severe iodine deficiency and has a high infantmortality rate. We investigated whether iodine replacement through iodination of the irrigation water would decrease infant mortality.

METHODS

We added potassium iodate to irrigation water over a 2 to 4 week period beginning in 1992 in certain areas of three townships (Tusala, Long Ru, and Bakechi). Logistic regression analysis was used to compare the odds ratios for infant and neonatal mortality in treated and intreated areas.

FINDINGS

The median urinary iodine concentration significantly increased in women of child-bearing age from < 10 micrograms/L to 55 micrograms/L. Infant-mortality rates decreased in the treated areas of Long Ru (mean [SD] 58.2 [4.4] per 1000 births to 28.7 [7.1] per 1000 births), Tusala (47.4 [12.4] per 1000 births to 19.1 [1.5] per 1000 births), and Bakechi (106.2 [9.5] per 1000 births to 57.3 [7.3] per 1000 births). Similar results were also seen for neonatal mortality. On regression analysis iodine treatment and time were significant independent predictors of infant mortality.

INTERPRETATION

Iodine supplementation of irrigation water in areas of severe iodine deficiency decreases neonatal and infant mortality. Iodine replacement has probably been an important factor in the national decrease in infant mortality in China.

Lanthionine-somatostatin analogs: synthesis, characterization, biological activity, and enzymatic stability studies

A series of cyclic somatostatin analogs containing a lanthionine bridge have been subjected to studies of structure-activity relationships. A direct synthesis of the thioether bridged analog (1) of sandostatin (SMS 201,995) and several lanthionine hexa-, hepta-, and octapeptides was carried out by using the method of cyclization on an oxime resin (PCOR) followed by condensation reactions in solution. The structures of the target peptides were analyzed by liquid secondary ion mass spectrometry (LSIMS) and subjected to high-energy collision-induced dissociation (CID) studies after opening of the peptide ring by proteolytic cleavage. The biological activities of these compounds have been evaluated by assaying their inhibitory potencies for the release of growth hormone (GH) from primary cultures of rat anterior pituitary cells, as well as by their binding affinities to cloned somatostatin receptors (SSTR1-5). The structural modification of sandostatin by introducing a lanthionine bridge resulted in a significantly increased receptor binding selectivity. The lanthionine octapeptide with C-terminal Thr-ol (1) showed similar high affinity for rat SSTR5 compared to somatostatin[1-14] and sandostatin. However, it exhibits about 50 times weaker binding affinity for mSSTR2b than sandostatin. Similarly, the lanthionine octapeptide with the C-terminal Thr-NH2 residue (2) has higher affinity for rSSTR5 than for mSSTR2B. Both peptides (compounds 1 and 2) have much lower potencies for inhibition of growth hormone secretion than sandostatin. This is consistent with their affinities to SSTR2, the receptor which is believed to be linked to the inhibition of growth hormone release by somatostatin and its analogs. The metabolic stability of lanthionine-sandostatin and sandostatin have been studied in rat brain homogenates. Although both compounds have a high stability toward enzymatic degradation, the lanthionine analog has a 2.4 times longer half-life than sandostatin. The main metabolites of both compounds have been isolated and identified by using an in vivo technique (cerebral microdialysis) and mass spectrometry.

An approach for measuring ultrasonic backscattering from biological tissues with focused transducers

When the standard substitution method is used with a focused transducer to measure the backscattering coefficient from biological tissues including blood, it yields erroneous results. Extending the backscattering measurements to frequencies beyond 15 MHz necessitates the use of focused transducers because of the worsened signal-to-noise ratio--caused by the increased attenuation and the smaller transducer aperture size--in order to make the measurements close to the transducer. An approach which allows the use of focused transducers in backscattering measurements has been developed. It has been used to measure the backscattering coefficient of red cell suspensions of hematocrit ranging from a few percent to 30% in the frequency range from 5 MHz to 30 MHz. The results at hematocrits below 20% agree well with those obtained with the standard substitution method, although they differ as the hematocrit is increased beyond 20%. The experimental results also show that the fourth-power dependence of backscatter on frequency is in general approximately valid for suspended erythrocytes of hematocrit between 6% and 30%.

Bone mineral acquisition in low calcium intake children following the withdrawal of calcium supplement

Our recent 18-month calcium supplementation trial demonstrated a significant increase in radial bone mineral mass in 7-year-old children with calcium intake approximately 300 mg/day (Am J Clin Nutr 1994; 60: 744-50). The persistence of higher bone mass after cessation of calcium supplementation is unknown. This is a follow-up study to investigate the lasting effect of calcium supplementation on bone acquisition. Subjects were 159 Chinese children aged 8.7 years. Distal one-third radial bone mineral content (BMC) and bone width (BW) were measured by single-photon absorptiometry. After 12 months, the significant difference in mean +/- SD percentage radial BMC disappeared between the study and control groups (7.34 +/- 6.77% vs 8.67 +/- 6.46%, p > 0.05). Dietary calcium intakes were similar between the groups. During the supplementation phase, the study group had 17.9% greater BMC gain than that of controls. In the follow-up phase, however, the study group had 16.1% less BMC gain than that of controls. It appears that an increased acquisition rate during the supplementation phase was almost balanced by a reduced acquisition rate during follow-up phase. Moreover, throughout the entire 30-month period, the overall BMC acquisition rates of the study and control groups were 25% and 23.8%, respectively. Hence, the overall acquisition rate of the study group was only 5% higher than that of controls. Therefore, the effect of calcium supplementation on bone mineral gain appears to reflect a transient reduction in bone turnover rate. Longer-term calcium trials are necessary to confirm whether a sustainable higher calcium intake throughout childhood will enhance peak bone mass.

Evaluation of recombinant chitinase and SXP1 antigens as antimicrofilarial vaccines

Prior studies indicate that a microfilarial stage-specific chitinase is a possible candidate antigen for a transmission-blocking vaccine against Brugian filariasis. The antigen is a functional enzyme that progressively appears as microfilariae mature and become able to infect and develop in a susceptible mosquito vector. It is recognized by a monoclonal antibody that reduces microfilaremia in infected animals and by a subset of sera from infected persons who remain amicrofilaremic. Immunization of jirds with recombinant chitinase induced partial protection against microfilaremia resulting from subsequent infection with Brugia malayi, but did not reduce adult worm burdens. Vaccination was much less effective when administered during the prepatent stage of infection and was ineffective when given to microfilaremic jirds. The protective epitope appears to be located close to the carboxy terminus of the chitinase molecule. Immunization of jirds with SXP1, an antigen present in multiple worm stages, also reduced microfilaremia and, in some experiments, adult worm burdens, but hyperimmunization with a recombinant filarial myosin was not protective. These observations indicate that the relative timing of immunization and infection is an important factor in the efficacy of antimicrofilarial vaccines.

[Effect of microinjection of adrenaline (E) into the rostral ventrolateral medulla on the parameters of the hemorrheology]

Experiments were performed on SD rats. It was found that hyperviscosity could be induced by restrained conscious rats. Microinjection of adrenaline (E) into the rostral ventrolateral medulla (rVLM) resulted in a facilitatory increase in blood viscosity, which was blocked by bilateral microinjection of alpha-adrenoceptor antagonist (phentola mine) into the same area, but not by beta-adrenocetor antagonist (propranolol). Pretreatment of rVLM area with 6-hydroxydopamine (6-OHDA) or microinjection of phentolamine abolished stress-induced hyperviscosity, while propranolol was without effect. Apparently the E caused increase of the blood viscosity or stress-induced hyperviscosity may be mediated by activation of alpha-adrenoceptor in the rVLM.