Polarization-resolved output analysis of X-ray multiple-wave interaction

The polarization suppression of the interfering components in X-ray multiple-wave interaction is observed for the first time by using a polarization analyzer with an arbitrary inclination of the diffraction plane with respect to that of the investigated crystal. The condition for total suppression of the multiple-wave interaction outside the investigated crystals by a polarization analyzer is derived theoretically from the modified Born approximation. By means of the partial suppression of the strong interfering component, the increase in the visibility of multiple-wave interference is experimentally and theoretically demonstrated. The proposed experimental polarization-resolved technique provides an operational way to enhance the visibility of X-ray multiple-wave interaction outside the investigated crystals for direct phase determination.

Anomalous dispersion behavior of multiple-wave X-ray diffraction at absorption edges: determination of phase change at resonance

The effects of anomalous dispersion (resonance) on multiple reflection of x rays and their interference in crystals at atomic absorption edges are studied. Intensity ratios of two inversion-symmetry-related multiple diffractions at or near absorption edges exhibit highly phase-sensitive profiles with strong asymmetric characteristics, unlike those far from the edges. A new resonance perturbation Bethe approach is developed to explain this behavior. This leads to direct determination of the phase change for x-ray reflections at resonance.

The origin of Minnan and Hakka, the so-called "Taiwanese", inferred by HLA study

The Minnan and Hakka people groups, the so-called "Taiwanese", are the descendants of early settlers from the southeast coast of China during the last few centuries. Genetically they showed affinities to southern Asian populations, as determined by phylogenetic trees and correspondence analysis calculated from HLA allele frequencies. This corresponds historically with the fact that they are the descendants of the southeast coastal indigenous population (Yueh) of China and should therefore not be considered as descendants of "pure" northern Han Chinese. A33-B58-DRB1*03 (A33-Cw10-B58-DRB1*03-DQB1*02), the most common HLA haplotype among "Taiwanese", with a haplotype frequency of 6.3%, has also been found to be the most common haplotype among Thai-Chinese and Singapore Chinese, two other populations also originating from the southeast coast of China. These observations suggests that this haplotype is the most well-conserved ancient haplotype of the Yueh.

Comparison of in vitro growth-inhibitory activity of carboplatin and cisplatin on leukemic cells and hematopoietic progenitors: the myelosuppressive activity of carboplatin may be greater than its antileukemic effect

BACKGROUND

Carboplatin [cis-diammine(cyclobutane-1, 1-dicarboxylato)platinum(II)] has been shown to be an active agent for acute myeloid leukemia. This second-generation platinum drug has less nephrotoxicity and ototoxicity but more myelotoxicity than does the first-generation platinum drug cisplatin. The study was designed to elucidate whether their myelosuppressive activities equal their antileukemic effects.

METHODS

Cisplatin and carboplatin were used to treat four leukemic cell lines (CEM, HL60, K562 and U937), blast cells from 10 leukemic patients and hematopoietic progenitors from five umbilical cord blood samples.

RESULTS

The mean IC50 of leukemic cell lines was 0.4 and 6.2 microg/ml, the mean IC50 of patients' leukemic blasts was 2.0 and 22.4 microg/ml and the mean IC50 of hematopoietic progenitors (BFU-E, CFU-E and CFU-GM) was 1.8 and 1.7 microg/ml for cisplatin and carboplatin, respectively.

CONCLUSIONS

Carboplatin required a 10 times higher drug concentration than cisplatin to induce a similar degree of growth inhibition on leukemic cells. However, the hematopoietic progenitors responded equally to cisplatin and carboplatin at the same drug concentration. The results suggest that the myelosuppressive activity of carboplatin is greater than its antileukemic effect.

Early patterning of prelimbic cortical axons to the striatal patch compartment in the neonatal mouse

The striatum receives excitatory input from virtually the entire cerebral cortex. In the adult, this input is segregated into two functionally distinct compartments of the striatum, the patch (striosome) and matrix regions. This study determined whether the patterning of corticostriatal afferents from the prelimbic cortex to the striatal patch compartment develops during the early period of collateral formation or instead at the time of peak synaptogenesis. Initial formation of corticostriatal axon collaterals was observed by embryonic day (E) 19. Quantification of corticostriatal collaterals revealed a significant increase in the number and complexity of collateral branches at postnatal day 6 as compared to E19. Concomitant with the increase in collateral branching, a heterogeneous pattern of collateralization consisting of parallel rows of corticostriatal collaterals was observed in the medial striatum. In addition to the rows, clusters of corticostriatal axons occurred more laterally. These clusters colocalized with patches of dense tyrosine hydroxylase-positive fibers, a marker for the striatal patch compartment in the neonatal mouse. Together, these data indicate that corticostriatal patterning occurs during the period of early axon collateralization resulting in a segregation of corticostriatal axon collaterals from the prelimbic cortex to the striatal patch compartment.

Endomorphin-1 and endomorphin-2 induce the expression of c-FOS immunoreactivity in the rat brain

Using FOS immunoreactivity (FOSir) as an anatomical marker of neuronal activation, we examined the effects of intracerebroventricular (i.c.v.) injections of endomorphin-1 (EM-1) and endomorphin-2 (EM-2) in the rat brain to determine the sites of action of these two mu-opioid ligands. Radiant heat tail flick latency, as a measure of behavioral effects, was prolonged by either EM-1 or EM-2 administration. Dose-dependent EM-1- and EM-2-induced FOSir were observed in various nuclei throughout the rostral-caudal axis of the rat brain. While there was some overlap, EM-1-induced FOSir was more prevalent than EM-2. The pattern of EM-induced FOSir was similar to the distribution of EM immunoreactivity (EMir). However, some sites with little or no detectable EMir exhibited FOSir, while other nuclei with marked EMir showed only sparse FOSir. EM-induced FOSir was correlated with mu-opioid receptor location in most brain areas. However, EM-induced FOSir was absent in the caudate putamen and the accumbens nucleus, both areas of high mu-opioid receptor density.

Role of type III collagen in bladder filling

The function of the urinary bladder is to store urine at low pressure and expel it periodically. To accomplish this, it must have the appropriate structural properties to accommodate slow but continuous volume changes. While much is presently known about the functional measurements of compliance, relatively little is known about the structural basis of compliance. In the present study, immunohistochemistry has been used to localize type III collagen fibers in the bladder wall at different intravesical volumes. To improve the resolution of these fibers, confocal microscopy was utilized to determine the changes in type III collagen fiber orientation and correlate them with the degree of mechanical distension of the bladder wall at partial and full capacity. We demonstrate that there were significant changes in both the orientation and conformation of type III collagen fibers during bladder filling. These observations support the view that volume accommodation in the bladder is achieved by changes in the arrangement of type III collagen. These data suggest that abnormal deposition or arrangement of type III collagen fibers can have an impact on normal bladder function.

Survey of Spirometra erinaceieuropaei in frogs in Taiwan and its experimental infection in cats

Eighteen of 56 (32.1%) wild Rana limnocharis from central and south Taiwan were found to contain plerocercoids of Spirometra erinaceieuropaei. This is the first report of S. erinaceieuropaei infections in frogs in Taiwan, with the plerocercoids being recovered from the thigh and back muscles or under the skin. Other species of frogs examined, including nine wild R. latouchii, one wild Buergeria robustus and 110 cultured R. rugulosa were free of infection. The plerocercoids were orally inoculated into four cats; three of which were each given a single plerocercoid and one a dose of three plerocercoids. Daily faecal examination showed that two cats started shedding eggs of S. erinaceieuropaei on day 8 postinfection (PI) and the other two on day 10 PI. The highest eggs per gram and eggs per day for a single worm was found to be 428,000 and 14,416,000 respectively. Only the cat inoculated with three plerocercoids shed proglottids in its faeces during the 2 month observation period.

MDM2 mRNA expression is a favorable prognostic factor in non-small-cell lung cancer

MDM2 is one of the downstream target genes for transcriptional activation by the product of the p53 tumor-suppressor gene. Transactivation of MDM2 gene expression is represented by the presence of a functional p53 protein. We hypothesized that MDM2 mRNA expression may be a more suitable prognostic factor than p53 or MDM2 protein expression and p53 gene mutations. In this study, expression of MDM2 mRNA, p53 protein, and MDM2 protein and mutations of the p53 gene were assessed in 81 lung tumor tissue specimens using RT-PCR, immunohistochemistry, and direct sequencing among exons 5-8, respectively. By immunohistochemistry, 33 and 42 of 81 patients with p53 (40.7%) and MDM2 (51.5%) protein expression were found in lung tumor specimens, respectively. The p53 direct sequencing data indicated that 13 of 81 patients (16.0%) had p53 mutations. However, Kaplan-Meier analysis showed that p53 protein and MDM2 protein expression and p53 mutation were not useful as prognostic factors. Interestingly, the survival of patients with MDM2 mRNA expression was longer than that of patients without MDM2 mRNA expression, though MDM2 mRNA expression was not associated with clinicopathological parameters, including tumor grade, tumor stage, tumor type, and TNM values. Moreover, Cox regression analysis showed that MDM2 mRNA expression was a significantly independent favorable prognostic factor in non-small-cell lung cancer (NSCLC) patients. Thus, measuring MDM2 mRNA expression using RT-PCR may be a simple, useful approach for predicting the survival of NSCLC patients.

The effect of electroporation on iontophoretic transdermal delivery of calcium regulating hormones

Electrically-assisted delivery by iontophoresis and/or electroporation was used in vitro to deliver the calcium regulating hormones, salmon calcitonin (sCT) and parathyroid hormone (1-34) (PTH) through human epidermis. Such delivery could be useful for chronic treatment of post-menopausal osteoporosis and other clinical indications as a superior alternative to parenteral delivery. sCT (50 microg/ml) or PTH (1-34) (100 microg/ml) formulation was prepared in citrate buffer (pH 4.0 or 5.0, respectively). Epidermis separated from human cadaver skin was used. Iontophoresis was applied using a constant current power source and electroporation with an exponential pulse generator. Silver/silver chloride electrodes were used. A combination of electroporation and iontophoresis resulted in higher transdermal permeation than either one technique alone. Electroporation also shortened the lag time of iontophoretic transdermal delivery of salmon calcitonin. Pulsing at lower voltages followed by iontophoresis did not result in increased transport (over iontophoresis alone), perhaps because the transdermal voltage was very low. The transdermal transport of salmon calcitonin by pulsing with 15 pulses (1 ppm) of 500 V (200 ms) followed by iontophoresis led to a quick input and high flux. The average transdermal voltage was only about 50 V for a 500 V study.

Chronic cocaine alters hemodynamics and leukocyte-endothelial interactions in rat mesenteric venules

We investigated the effects of chronic cocaine exposure on the microcirculation in the rat mesenteric venules under both non-inflammatory and FMLP-induced inflammatory conditions. Chronic cocaine significantly increased WBC rolling flux in both conditions, and potentiated FMLP-induced leukocyte-endothelial cell adhesion (LEA). In cocaine-treated animals, total WBC number increased by 91%, and the ratio of white blood cell to red blood cell velocity was significantly lower, while vessel diameter was unchanged. Chronic cocaine decreased serum levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6), but had no effect on interleukin-1 beta (IL-1beta). Expression of intercellular adhesion molecule-1 (ICAM-1) was increased in mesenteric venules following chronic cocaine exposure, and may be one of the mechanisms underlying enhancement of FMLP-induced LEA. The increase in WBC count, WBC flux and LEA, and the change in cell velocity seen in the cocaine-treated animals could cause a decrease in effective vessel diameter and a change in intravascular resistance, and may underlie the progressive vascular damage seen in chronic cocaine-abusing individuals.

Management of scrap computer recycling in Taiwan

It is estimated that approximately 300,000 scrap personal computers are generated each year in Taiwan [S.-L. Chang, A Study on the Scrap Computer Treatment Cost, Environment Protection Administration of Taiwan, December 1998 (in Chinese)]. The disposal of such a huge number of scrap computers presents a difficult task for the island due to the scarcity of landfills and incineration facilities available locally. Also, the hazardous materials contained (i.e., phosphor coatings of cathode ray tubes (CRTs), batteries, polychlorinated biphenyl capacitors, mercury-containing parts, liquid crystal display, high-lead content CRT funnel glass, and plastic containing flame-retardant bromine, etc.) in the scrap computers may seriously pollute the environment if they are not properly disposed of. Therefore, the EPA of Taiwan declared scrap personal computers the producer's recycling responsibility as of July 1997. Under this decree, the manufacturers, importers and sellers of personal computers have to properly recover and recycle the scrapped computers which they originally sell. On June 1, 1998, a producer responsibility recycling program for scrap computers was officially implemented in Taiwan. Under this program, consumers can bring their unwanted personal computers to the designated collection points and receive reward money. Currently, only six computer items are mandated to be recycled in this recycling program. They are notebooks, monitors, hard disks, power supplies, printed circuit boards and main frame shells. This article outlines the current scrap computer recycling system in Taiwan.

Transdermal iontophoretic delivery of salmon calcitonin

Electrically enhanced transdermal delivery of salmon calcitonin could be useful for chronic treatment of postmenopausal osteoporosis and other clinical indications as a superior alternative to parenteral delivery. Calcitonin (50 microg/ml) formulation was prepared in citrate buffer (pH 4.0). Epidermis separated from human cadaver skin was used. Most iontophoresis studies were done at a current density of 0.5 m A cm2. Silver/silver-chloride electrodes were used and calcitonin was found to be best delivered under the anode. The relationship between calcitonin flux and current density during iontophoresis was linear. Passive flux was zero. Flux increased with increasing concentration up to 250 microg/ml but then it levels off. Thus, transdermal delivery of salmon calcitonin may be accomplished to achieve therapeutic levels.

In vitro biocytin injection into perinatal mouse brain: a method for tract tracing in developing tissue

Injection of biocytin provides an effective method for labeling axonal projections. Several difficulties arise when this technique is employed in fetal or early postnatal animals in vivo, including limited access to injection sites and extended post-injection survival periods. To circumvent these problems, we adapted the technique of extracellular biocytin injection for use in explanted brain hemispheres of developing mice. Briefly, entire brain hemispheres from perinatal mice (E16-P9) were removed and placed in oxygenated aCSF in a brain slice recording chamber. Following visually guided injection of biocytin (2%) into the prelimbic cortex, the brains were then incubated in oxygenated artificial cerebrospinal fluid (aCSF) for varying periods of time and then immersion-fixed in 4% paraformaldehyde and 0.5% glutaraldehyde. The next day, the brains were sectioned and processed for biocytin histochemistry using the avidin-biotin-complex method. We examined the method of injection, electrode type, time of injection, and post-injection incubation period. We found that in E16-P9 animals iontophoresis of biocytin using 8- to 12-megaohm patch clamp electrodes for a duration of 10 min provides optimal axonal labeling. Post-injection incubation times of four or more hours are sufficient for labeling fine caliber collaterals as well as axon bundles that reach distances over 3 mm. In vitro injection of biocytin into explanted brain hemispheres provides a quick and easy method for tract tracing in developing brains.

Quantification of the learning curve for percutaneous dilatational tracheotomy

OBJECTIVES/HYPOTHESIS

Although numerous investigators have reported a bedside percutaneous dilatational tracheotomy (PDT) complication incidence similar to that of standard operative tracheostomy, others have proposed a "learning curve" for PDT resulting in increased complications early in individual or institutional experience with this procedure. The objective of this investigation is to characterize and quantify the proposed learning curve for PDT.

STUDY DESIGN

Prospective analysis of complication incidence for the first 100 PDT procedures performed in a local community hospital Department of General Surgery.

METHODS

Demographic data, patient disease variables, and patient anatomic features, as well as perioperative, postoperative, and late complications, were recorded prospectively. Patients were divided into sequential cohorts of 20 and were evaluated for complications at regular intervals.

RESULTS

Perioperative and late complication incidence was significantly higher in the first 20 patients who underwent PDT. However, postoperative complication incidence did not significantly vary with operator or institutional experience. In addition, patients with suboptimal anatomy were found to have a significantly increased complication incidence, independent of operator and institutional experience.

CONCLUSIONS

Percutaneous dilational tracheotomy has an identifiable learning curve that is most prominent in the first 20 patients treated. Early experience with PDT should be obtained under controlled circumstances, ideally the operating suite. Although most complications occur during acquisition of early experience with PDT, certain life-threatening complications such as tube dislodgment or inability to complete procedure may occur even after extensive experience is obtained. Bedside PDT has an acceptable complication incidence, but any surgeon employing this technique must be prepared to perform immediate standard open tracheotomy to minimize potentially lethal complications of this elective procedure.

Heterogeneity of Taiwan's indigenous population: possible relation to prehistoric Mongoloid dispersals

Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.

Characterization of a 5'-flanking region supporting the transcription of mouse thymosin beta-4 in mouse NIH3T3 cells

Expression of the gene coding for thymosin beta-4 (Tbeta-4), the major G-actin sequestering peptide in the cell, is regulated mainly at the level of transcription. In this study, we examined the nucleotide sequence of the 5'-flanking region (from -2202 to -881) of the mouse Tbeta-4 gene, and demonstrated that the DNA fragment from -278 to +410 of this gene was capable of directing the expression of a chloramphenicol acetyltransferase reporter gene in NIH3T3 cells. However, expression of the reporter gene in cells cannot be induced by interferon-alpha treatment even though a rapid activation of endogenous Tbeta-4 gene by this cytokine was observed. These results suggest that the projected interferon-stimulated response element (ISRE) might reside in other parts of the mouse Tbeta-4 gene.

Synthesis and antiviral activity of amino acid carbamate derivatives of AZT

Lipophilic amino acid methyl ester and methyl amide carbamates of 3'-azido-3'-deoxythymidine (AZT) were synthesized and their anti-HIV-1 activity in PBMCs was determined. The methyl amides were more potent (EC50s = 1.8-4.0 microM) than the methyl esters (EC50s = 2.0-20 microM). Carbamate hydrolysis by cell lysates and liberation of AZT was not observed for representative methyl ester or methyl amide AZT carbamates. No evidence of direct inhibition of HIV reverse transcriptase or integrase was observed.

Roles of the lamina propria and the detrusor in tension transfer during bladder filling

In this study, structural changes within the lamina propria and detrusor layers were analysed during development as a function of bladder filling. Second-, third- and full-term foetal bovine bladders were filled to 0%, 25%, 50%, 75% and 100% of their total capacity and snap frozen. The bladders were analysed histochemically and the relative thicknesses of the lamina propria and detrusor were measured. In all gestational stages examined, the total thickness of the bladder wall decreased during bladder filling. The lamina propria of the full-term bladder thinned at a consistently faster rate than did the detrusor. The lamina propria of second and third trimester bladders followed the same thinning pattern, except when the bladders were filled from 25% to 50% of their capacities. At these gestational stages, the detrusor thinned at a faster rate than the lamina propria. Our results demonstrate that the detrusor layer carries tension only during a specific portion of the filling cycle and only during the second and third trimesters. We conclude that the lamina propria acts as the capacitance layer, while the detrusor functions as the "limiting" or "girding" layer to prevent over-distension of the bladder wall.

Solution structure of component B from methane monooxygenase derived through heteronuclear NMR and molecular modeling

Methane monooxygenase (MMO) is a nonheme iron-containing enzyme which consists of three protein components: a hydroxylase (MMOH), an NADH-linked reductase (MMOR), and a small "B" component (MMOB) which plays a regulatory role. Here, 1H, 13C, 15N heteronuclear 2D and 3D NMR spectroscopy has been used to derive the solution structure of the 138 amino acid MMOB protein in the monomer state. Pulse field gradient NMR self-diffusion measurements indicate predominant formation of dimers at 1 mM MMOB and monomers at or below 0.2 mM. MMOB is active as a monomer. Aggregate exchange broadening and limited solubility dictated that multidimensional heteronuclear NMR experiments had to be performed at a protein concentration of 0.2 mM. Using 1340 experimental constraints (1182 NOEs, 98 dihedrals, and 60 hydrogen bonding) within the well-folded part of the protein (residues 36-126), MMOB structural modeling produced a well-defined, compact alpha/beta fold which consists of three alpha-helices and six antiparallel beta-strands arranged in two domains: a betaalphabetabeta and a betaalphaalphabetabeta. Excluding the ill-defined N- and C-terminal segments (residues 1-35 and 127-138), RMS deviations are 1.1 A for backbone atoms and 1.6 A for all non-hydrogen atoms. Compared to the lower resolution NMR structure for the homologous protein P2 from the Pseudomonas sp. CF600 phenol hydroxylase system (RMSD = 2.48 A for backbone atoms) (Qian, H., Edlund, U., Powlowski, J., Shingler, V., and Sethson, I. (1997) Biochemistry, 36, 495-504), that of MMOB reveals a considerably more compact protein. In particular, MMOB lacks the large "doughnut" shaped cavity reported for the P2 protein. This difference may result from the limited number of long-range NOEs that were available for use in the modeling of the P2 structure. This NMR-derived structure of MMOB, therefore, presents the first high-resolution structure of a small protein effector of a nonheme oxygenase system.

Cocaine enhances brain endothelial adhesion molecules and leukocyte migration

Leukocyte infiltration of cerebral vessels in cocaine-associated vasculopathy suggests that cocaine may enhance leukocyte migration. We have investigated cocaine's effects on leukocyte adhesion in human brain microvascular endothelial cell (BMVEC) cultures and monocyte migration in an in vitro blood-brain barrier (BBB) model constructed with BMVEC and astrocytes. Cocaine (10(-5) to 10(-9) M) enhanced adhesion of monocytes and neutrophils to BMVEC. In the BBB model, cocaine (10(-4) to 10(-8) M) enhanced monocyte transmigration. Cocaine increased expression of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1, CD54), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1) on BMVEC. The peak effect on ICAM-1 expression was between 6 and 18 h after treatment. ICAM-1 was increased by cocaine in BMVEC, but not in human umbilical vein endothelial cells, and the enhancement was greater in a coculture of BMVEC with monocytes. ICAM-1 expression was enhanced by a transcriptional mechanism. Polymyxin B inhibited up-regulation of adhesion molecules by LPS but not by cocaine. In LPS-activated BMVEC/monocyte coculture, cocaine increased secretion of tumor necrosis factor-alpha and interleukin-6. Taken together, these findings indicate that cocaine enhances leukocyte migration across the cerebral vessel wall, in particular under inflammatory conditions, but the effects are variable in different individuals. Cocaine's effects are exerted through a cascade of augmented expression of inflammatory cytokines and endothelial adhesion molecules. These could underlie the cerebrovascular complications of cocaine abuse.

Antiviral nucleoside drug delivery via amino acid phosphoramidates

Stable and water soluble amino acid phosphomonoester amidates of AZT were synthesized and shown to have potent anti-HIV-1 activity. Intracellular and cell extract metabolism studies revealed that these compounds are likely to be enzymatically converted to the corresponding monophosphates. In addition, we have shown that the half life and tissue distribution of a phosphoramidate of AZT is 5 and 10-fold greater, respectively, than AZT.

A case of extraadrenal pheochromocytoma associated with adrenal cortical nodular hyperplasia and papillary thyroid carcinoma

A 64-year-old woman was admitted in November, 1996 for fluctuating blood pressure. There was multinodular goiter in her neck. High urine VMA and serum aldosterone were noted. Computed tomography showed an oval lesion in the left adrenal gland. Left adrenalectomy was performed and the pathology was proved to be adrenal cortical nodular hyperplasia. Fluctuating blood pressure and high urine VMA persisted after the operation. CT scan of the abdomen revealed a soft tissue mass in lower abdomen. The patient was admitted again in September, 1997. Laboratory examinations showed normal serum aldosterone, normal plasma renin activity and high urine VMA. Aspiration cytology of the thyroid gland disclosed papillary thyroid carcinoma. [131I]-metaiodobenzylguanidine image revealed a high uptake lesion in the right L-3 paravertebral area. Tumor excision and thyroidectomy were performed. The pathology was reported as extraadrenal pheochromocytoma and papillary thyroid carcinoma. Papillary thyroid carcinoma is rarely associated with pheochromocytoma. To our knowledge, this paper is the first report of a patient with extraadrenal pheochromocytoma associated with papillary thyroid carcinoma and adrenal cortical nodular hyperplasia.

An insulin-dependent hypoglycaemia induced by electroacupuncture at the Zhongwan (CV12) acupoint in diabetic rats

Acupuncture at the Zhongwan acupoint has been widely used in traditional Chinese medicine to relieve symptoms of diabetes mellitus. Our study investigated the effect on plasma glucose of electroacupuncture applied at the Zhongwan acupoint in rat diabetic models. Plasma concentrations of insulin, glucagon and beta-endorphin- were also determined using radioimmunoassay. A decrease in plasma glucose was observed in rats after electroacupuncture (15 Hz, 10 mA) for 30 min at the Zhongwan acupoint. This was observed in normal rats and rat models with Type II (non-insulin-dependent) diabetes mellitus. No significant effect on plasma glucose was observed in rat models with Type I (insulin-dependent) diabetes mellitus: neither the streptozotocin (STZ)-induced diabetic rats nor the genetic (BB/W) rats. Further, the hypoglycaemic action of electroacupuncture stimulation disappeared in rats with insulin-resistance induced by an injection of human long-acting insulin repeated daily to cause the loss of tolbutamide-induced hypoglycaemia. An insulin-related action can thus be hypothesised. This hypothesis is supported by an increase in plasma insulin-like immunoreactivity after electroacupuncture stimulation in normal rats. Participation of glucagon was ruled out because there was no change in plasma glucagon-like immunoreactivity resulting from electroacupuncture stimulation. In addition to an increase in plasma beta-endorphin-like immunoreactivity, the plasma glucose lowering action of electroacupuncture stimulation at Zhongwan acupoint was abolished by naloxone in a sufficient dose to block opioid receptors. Thus we suggest that electroacupuncture stimulation at the Zhongwan acupoint induces secretion of endogenous beta-endorphin which reduces plasma glucose concentration in an insulin-dependent manner.

Cocaine opens the blood-brain barrier to HIV-1 invasion

Cocaine abuse has been associated with vasculitis and stroke, and is suspected to influence the progression of AIDS dementia. Cocaine may enhance HIV-1 neuroinvasion by actions directed at the blood-brain barrier. HIV-1 appears to penetrate the human brain microvascular endothelial cell barrier by a paracellular route breached by tumor necrosis factor-alpha (TNF-alpha). Cocaine's effects on the blood-brain barrier were investigated using human brain microvascular endothelial cells and peripheral blood monocytes. Cocaine (10(-5) M and 10(-6) M) increased molecular permeability of the barrier and viral invasion by the macrophage-tropic HIV-1(JR-FL) into the brain chamber. Cocaine also augmented apoptosis of brain endothelial cells and monocytes, increased secretion of four chemokines (interleukin-8, interferon-inducible protein-10, macrophage inflammatory protein-1alpha, and monocyte chemoattractant protein-1) and the cytokine, TNF-alpha, by human monocytes. TNF-alpha enhanced invasion of the brain compartment by macrophage-tropic, lymphotropic, and bitropic HIV-1 strains. These data indicate that HIV-1 neuroinvasion can be increased by (a) cocaine's direct effects on brain microvascular endothelial cells and (b) paracrine effects of cocaine-induced pro-inflammatory cytokines and chemokines on the blood-brain barrier.