Pentagon-shaped 0 degrees -cut BaTiO3 as an efficient self-pumped phase conjugator

A pentagon-shaped 0 degrees-cut undoped BaTiO(3) crystal was used to construct a high-quality self-pumped phase conjugator. The conjugator shows a steady phase-conjugate output with a high reflectivity (as high as approximately 68%), a fast rising time, and a large angular range of acceptance. It also shows a good fidelity in the phase-conjugate reconstructed image; the resolution reaches 17 microm.

Laparoscopic anterior lumbar interbody fusion

In recent years, there has been an unprecedented increase in the number of patients undergoing treatment with interbody fusion devices for degenerative disease of the lumbar spine. These devices can be placed either anteriorly or posteriorly. With the advent of minimally invasive surgery and the increasing ability of general surgeons to perform transperitoneal procedures laparoscopically, a new laparoscopic technique has been developed for placing lumbar interbody fusion devices. Although this procedure has some advantages over posterior lumbar interbody fusion, it is not without significant risk, and the learning curve is steep. The authors review a series of 32 consecutive patients who underwent single-level laparoscopic anterior lumbar interbody fusion at L4–5 or L5–S1 over a 2-year period for the treatment of single-level lumbar degenerative disease. In this report they review the technical aspects of the procedure and the important lessons they have learned through their early experience with this technique.

Normal approximation diagnostics for the Cox model

We discuss two diagnostic methods for assessing the accuracy of the normal approximated confidence region to the likelihood-based confidence region for the Cox proportional hazards model with censored data. The proposed diagnostic methods are extensions of the contour measures of Hodges (1987, Journal of the American Statistical Association 82, 149-154) and Cook and Tsai (1990, Journal of the American Statistical Association 85, 770-777) and the curvature measures of Jennings (1986, Journal of the American Statistical Association 81, 471-476) and Cook and Tsai (1990). These methods are also illustrated in a study of hepatocyte growth factor in patients with lung cancer and a Mayo Clinic randomized study of participants with primary biliary cirrhosis.

Effects of peritumoural oedema on cerebral blood flow and cerebrovascular reactivity in patients with alert consciousness

The effects of peritumoural oedema on cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were studied in 18 patients with alert consciousness. Hemispheric mean CBF was measured by performing first-pass radionuclide angiography using technetium-99m hexamethylpropylene amine oxime. CVR was measured as the percentage change from the baseline mean CBF value after acetazolamide administration. Patients were classified into three groups according to the severity of peritumoural oedema. The mean CBF of both hemispheres in each group was not significantly different from that of age-matched controls. CVR was preserved in patients with mild peritumoural oedema (n=6), but was significantly (P<0.01) reduced in patients with moderate (n=7) and severe peritumoural oedema (n=5). No significant correlation was found between the degree of midline shift and the mean CVR of both hemispheres (P=0.09). Surgical removal of the tumour significantly (P<0.05) improved the impaired CVR, although the mean CBF did not change. Administration of glucocorticoid improved the impaired CVR, without a change in the mean CBF, in a patient with a metastatic brain tumour. We conclude that CVR is impaired by the development of peritumoural oedema prior to changes in mean CBF.

Prediction of effectiveness of shunting in patients with normal pressure hydrocephalus by cerebral blood flow measurement and computed tomography cisternography

Measurement of cerebral blood flow (CBF) and computed tomography (CT) cisternography were performed in 37 patients with a tentative diagnosis of normal pressure hydrocephalus (NPH) to predict their surgical outcome. The mean CBF of the whole brain was measured quantitatively by single photon emission computed tomography with technetium-99m-hexamethylpropylene amine oxime before surgery. The results of CT cisternography were classified into four patterns: type I, no ventricular stasis at 24 hours; type II, no ventricular stasis with delayed clearance of cerebral blush; type III, persistent ventricular stasis with prominent cerebral blush; type IV, persistent ventricular stasis with diminished cerebral blush and/or asymmetrical filling of the sylvian fissures. The mean CBF was significantly lower than that of age-matched controls (p < 0.005). Patients with a favorable outcome had a significantly higher mean CBF than patients with an unfavorable outcome (p < 0.005). Patients with the type I pattern did not respond to shunting. Some patients with type II and III patterns responded to shunting but improvement was unsatisfactory. Patients with type IV pattern responded well to shunting, and those with a mean CBF of 35 ml/100 g/min or over achieved a favorable outcome. The combination of CBF measurement and CT cisternography can improve the prediction of surgical outcome in patients with suspected NPH.

Effect of challenge dose and route on porcine reproductive and respiratory syndrome virus (PRRSV) infection in young swine

Porcine reproductive and respiratory syndrome virus (PRRSV) is perceived to be highly infectious because of the rapid spread of the virus through populations of domestic swine throughout the world. However, no information has been published on the minimum infectious dose of PRRSV and the effect of challenge dose on clinical response. In this experiment, ten groups of pigs (n = 3 per group) were inoculated with one of five different quantities (10(1)-10(5) fluorescent foci units per millilitre) of PRRSV (isolate ISU-P) by either intramuscular or intranasal routes. Clinical signs and body temperature were monitored for 21 days. Serum was collected periodically throughout the study period to monitor the presence of virus in serum and the early immune response of pigs. A 2-mL inoculum containing 10(1) fluorescent foci units of virus per millilitre was found sufficient to achieve infection by either route. Time to onset of clinical signs was highly associated with challenge dose (P < 0.01), regardless of route of exposure. However, no dose- or route-dependent differences in the severity of clinical manifestation were observed. No significant differences in the time of onset or degree of humoural immune response to PRRSV infection were observed between different treatment groups. However, intramuscular exposure appeared to induce a more uniform antibody response compared to intranasal exposure. These results confirmed that PRRSV is highly infectious; a fact that should be taken into consideration when designing strategies for the prevention and control of PRRSV.

Looking back on the discovery of alpha-bungarotoxin

This review is a personal narration by a retiring pharmacologist from Taiwan who looks back at his discovery of alpha-bungarotoxin from the historical perspective of Taiwan during the last 50 years, with accounts of his experiences and his efforts to overcome hardship. How the alpha-toxin was isolated and characterized as an irreversible specific nicotinic acetylcholine (ACh) receptor antagonist, and how it subsequently became a useful experimental probe are presented here. The dilemma of differentiating the actions of tubocurarine and alpha-bungarotoxin is analyzed. The author also outlines findings based on work done in his laboratory using alpha-bungarotoxin as a tool on particular aspects of synaptic transmission. These include presynaptic receptor for positive feedback of transmitter release, explosive release of ACh, up- and downregulation of ACh receptors after chronic drug treatment, autodesensitization of junctional ACh receptors, differences in action between natural transmitter and exogenous agonists and that between junctional and extrajunctional ACh receptors. Some experimental pitfalls, in which biomedical scientists are frequently trapped, are raised. Finally, some anecdotes are appended from which the reader may further understand scientific life in the 20th century, including its joys and regrets.

Transcriptional repression of Stat6-dependent interleukin-4-induced genes by BCL-6: specific regulation of iepsilon transcription and immunoglobulin E switching

The BCL-6 proto-oncogene encodes a POZ/zinc-finger transcription factor that is expressed in B cells and a subset of CD4(+) T cells within germinal centers. Recent evidence suggests that BCL-6 can act as a sequence-specific repressor of transcription, but the target genes for this activity have not yet been identified. The binding site for BCL-6 shares striking homology to the sites that are the target sequence for the interleukin-4 (IL-4)-induced Stat6 (signal transducers and activators of transcription) signaling molecule. Electrophoretic mobility shift assays demonstrate that BCL-6 can bind, with different affinities, to several DNA elements recognized by Stat6. Expression of BCL-6 can repress the IL-4-dependent induction of immunoglobulin (Ig) germ line epsilon transcripts, but does not repress the IL-4 induction of CD23 transcripts. Consistent with the role of BCL-6 in modulating transcription from the germ line epsilon promoter, BCL-6(-/-) mice display an increased ability to class switch to IgE in response to IL-4 in vitro. These animals also exhibit a multiorgan inflammatory disease characterized by the presence of a large number of IgE(+) B cells. The apparent dysregulation of IgE production is abolished in BCL-6(-/-) Stat6(-/-) mice, indicating that BCL-6 regulation of Ig class switching is dependent upon Stat6 signaling. Thus, BCL-6 can modulate the transcription of selective Stat6-dependent IL-4 responses, including IgE class switching in B cells.

Towards metabolic sink therapy for mut methylmalonic acidaemia: correction of methylmalonyl-CoA mutase deficiency in T lymphocytes from a mut methylmalonic acidaemia child by retroviral-mediated gene transfer

The pathology associated with mut methylmalonic acidaemia (MMA) is caused by systemic accumulation of methylmalonate. Therefore, removal of methylmalonate from the circulation of affected individuals by an engineered metabolic system is proposed as a potential treatment. The haematopoietic cell is a potential site for such a metabolic system because of its direct contact with the accumulated metabolite and the demonstrated safety and ease in utilizing this cell. In this study, we assessed the feasibility of developing a haematopoietic cell-based methylmalonate sink by analysing propionate/methylmalonate metabolism in a variety of haematopoietic cells. The results show that propionate metabolism and methylmalonyl-CoA mutase (MCM) activity are intact in primary T cells, EBV-B cells, and CD34+ haematopoietic stem cell-derived granulocytes, whereas they are defective in those from a mut MMA child. Moreover, normal T and EBV-B cells clear methylmalonate from the medium at a significant rate. Transduction of MCM-deficient T cells with a recombinant retrovirus encoding the human MCM cDNA results in correction of propionate metabolism. These results establish the basis for developing haematopoietic cell-based metabolic sink therapy for mut MMA by T lymphocyte/haematopoietic stem cell-directed gene transfer.

Birth after the injection of sperm and the cytoplasm of tripronucleate zygotes into metaphase II oocytes in patients with repeated implantation failure after assisted fertilization procedures

OBJECTIVE

To assess the technique of injecting a single sperm and cytoplasm obtained from tripronucleate zygotes into metaphase II oocytes for the treatment of patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

DESIGN

Clinical study.

SETTING

Private infertility clinic.

PATIENT(S)

Patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

INTERVENTION(S)

The metaphase II oocytes of recipients were injected with their husbands' spermatozoa and cytoplasm aspirated from the tripronucleate zygotes of donors.

MAIN OUTCOME MEASURE(S)

Fertilization after cytoplasm and sperm injection, embryo development, and successful pregnancy.

RESULT(S)

In total, 62 metaphase II oocytes from nine recipients were injected. Of the 62 injected oocytes, 3 (5%) degenerated and 43 (69%) had two pronuclei 18 hours after injection. Thirty-nine oocytes with two pronuclei cleaved to the two-cell to six-cell stage after another 24 hours of culture. All cleaved embryos were transferred into the uteruses of recipients. Four clinical pregnancies occurred in four recipients. No abnormal chromosomes were observed after amniocentesis and karyotyping in all pregnancies. Five healthy infants were born.

CONCLUSION(S)

Injection of the cytoplasm of tripronucleate zygotes may enhance the clinical pregnancy rate in patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

Incidence and management of subdural hematoma/hygroma with variable- and fixed-pressure differential valves: a randomized, controlled study of programmable compared with conventional valves

Shunt systems with differential pressure valves are prone to the complications of overdrainage. A programmable valve permits adjustment of the opening pressure of the valve. In this paper the authors report the incidence of subdural fluid collections in a randomized trial of programmable compared with conventional valves, and they describe methodologies used in management of this complication.

A multiinstitutional, prospective, randomized trial of the Codman Hakim programmable valve and conventional fixed-pressure valves was undertaken. Two classes were defined: “new” and “replacement” valves. Randomization of the type of valve in each group was performed at each study site. Clinical and radiological studies were required at fixed intervals over a 104-week period. All complications were reported. The experimental valves were required to be reprogrammed after magnetic resonance imaging studies, but all other decisions regarding pressure setting were left to each investigator.

Three hundred seventy-seven patients were randomized; 194 were treated with a programmable valve and 183 with a fixed-pressure valve. The two groups were statistically similar in demographic composition, as were the “new” and “replacement” categories. The investigators made 540 valve pressure changes (five per patient; range one-41 changes). More than half of the reprogramming adjustments were made in the first 3 months postplacement; 70% were made within 6 months. More than half of all reprogramming adjustments were required in a group of 30 patients.

Four treatment modalities were observed: 1) 30% of the fluid collections resolved spontaneously (25% in the patients with programmable valves and 36.3% in those with conventional valves) and were largely found to be hygromas in infants and children; 2) four subdural fluid collections were unresolved and under observation; 3) the subdural hematoma was drained and the shunt removed (in 8.3% of patients with the programmable valve and 36.3% of those with the control valve); 4) the pressure of programmable valve was raised in 58% of patients (seven of 12), and this increase in opening pressure was a feature used by investigators to affect treatment.

There was no significant difference in the incidence of subdural fluid collections between the programmable and fixed-pressure valve treatment groups. The programmable feature provided a considerable advantage in treatment when subdural collections occurred.

Hepatic apoptotic activity following transient normothermic inflow occlusion and reperfusion in the swine model

Accelerated hepatic apoptosis was first described in portal vein-ligated livers but has since been reported in a variety of liver injuries. Because porto-prival states can induce apoptosis we sought to determine whether transient ischemic periods followed by reperfusion would trigger such cell death. The cytokines TNF-alpha and TGF-beta are known to facilitate apoptosis and are released in response to a number of stimuli including ischemia. We also investigated alterations in plasma and tissue levels of these cytokines which might lend support to their role in increased apoptotic activity following ischemia/reperfusion. Female pigs were used as the experimental model. Inflow occlusion of portal and hepatic arterial blood was performed to a portion of the swine liver directing the entire splanchnic flow to the remaining hepatic lobes for a period of 2 h. The livers were then reperfused and plasma and tissue samples taken for determination of apoptotic activity utilizing cell death immunoperoxidase staining of 3'-OH DNA ends generated by fragmentation and ELISA assay of histone-associated DNA fragments. Plasma and tissue levels of TNF-alpha and plasma levels of TGF-beta were determined by ELISA assay. An increase in apoptotic activity following reperfusion was seen at Day 2 and Day 4 compared to preischemic values by the cell death stain. The ELISA cell death assay showed an increase in apoptotic activity at 60 min, Day 2, and Day 4. Moreover, the ELISA cell death assay showed enhanced apoptotic activity in "hyperperfused" hepatic lobes compared to preischemic, or resting, liver. This was also observed when compared to sham-operated animals. Surprisingly, there was no detectable increase in plasma TNF-alpha or TGF-beta levels following ischemia/reperfusion, although homogenized liver TNF-alpha levels were increased at 60 min and Day 2 following reperfusion. We conclude that transient hepatic inflow occlusion followed by reperfusion can induce increased apoptotic activity in the swine model. Furthermore, increased apoptotic activity also occurs in the hyperperfused liver raising the possibility of a locally active factor or global hepatic expression of receptor activity in response to ischemia/reperfusion. This period of ischemia/reperfusion did not produce a detectable increase in circulating cytokine levels, and accelerated apoptosis could not be linked to heightened TNF-alpha or TGF-beta plasma activity. Higher tissue levels of TNF-alpha could reflect enhanced binding to TNF cell surface receptors or amplified receptor expression.

Inhibition of quantal release from motor nerve by wortmannin

1. The effects of wortmannin, an inhibitor of phosphatidylinositol (PI) kinases and myosin light chain kinase, on the quantal release of neurotransmitter from mouse phrenic nerve were investigated. 2. Wortmannin (10 - 100 microM) initially enhanced, thereafter progressively depressed spontaneous quantal discharge (miniature endplate potential, mepp). The mean amplitude and the amplitude distribution of mepp were not altered. 3. The compound inhibited and prevented the intensive quantal release evoked by high KC1 solution as well as the mepp burst induced by alpha-latrotoxin, a polypeptide toxin that possesses Ca2+-independent synaptic action to trigger quantal release. The inhibitory actions of wortmannin were partially reversible. 4. Wortmannin depressed the amplitude of endplate potentials (epps) and increased the coefficient of variance of epps. The profile of epps in response to high frequency nerve stimulation exhibited fluctuations between run-down and run-up. The phenomenon is thus different from the consistency of run-up characteristic as the motor nerve Ca2+ channel is blocked by omega-agatoxin IVA. 5. LY294002, another inhibitor of PI 3-kinase, raised mepp frequency without causing late phase suppressions. The compound did not inhibit KC1-, alpha-latrotoxin- or nerve stimulation-evoked quantal release. 6. The results suggest that wortmannin could depress quantal release beyond the step of Ca2+ channel blockade, probably by interfering with the exocytotic cascade.

Introduction to PCR/OLA/SCS, a multiplex DNA test, and its application to cystic fibrosis

The field of medical, molecular diagnostics has grown rapidly over the last few years, becoming increasingly informative to both clinician and patient. As genes associated with specific diseases have been discovered and sequenced, many genotype-phenotype relationships have been defined. For those genetic diseases with associated, defined, gene mutations, sophisticated DNA diagnostic tests are being developed. As an example, the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene, is associated with Cystic Fibrosis (CF). We have developed a new molecular diagnostic technology, PCR/OLA/SCS, and applied it first to the diagnosis of CF. Test design in the field of molecular diagnostics must consider such characteristics as specificity, sensitivity, ease and speed of protocol, multiplex capacity, and cost. PCR/OLA/SCS addresses these requirements. Polymerase Chain Reaction (PCR) is widely used in both diagnostics and research. We have combined well established PCR technology with Oligonucleotide Ligation Assay (OLA) and Sequence-Coded Separation (SCS), two relatively new technologies.

Ultrarapid cryopreservation of human embryos: experience with 1,582 embryos

OBJECTIVES

To demonstrate the effectiveness of ultrarapid cryopreservation in human embryos.

DESIGN

Retrospective study.

SETTING

An IVF unit of a medical center.

PATIENT(S)

All cases received ultrarapid freezing (URF) of embryos and frozen embryo transfer.

INTERVENTION(S)

Embryos were placed in phosphate-buffered saline (PB1) + 20% maternal serum (MS) for 5 minutes. Embryos were loaded to the straws containing PB1 + MS + 0.25 M sucrose (SUC) + 3.5 M dimethyl sulfoxide for 3 minutes, and then were stored in a liquid nitrogen tank. Embryos were thawed in a 37 degrees C water for 6 seconds and then cultured in PB1 + MS + SUC for 10 minutes. Embryos were transferred into PB1 + MS for 5 minutes and were transferred into patients.

MAIN OUTCOME MEASURE(S)

The embryo grades before and after URF, the survival and transferred embryo numbers, and the pregnancy and abortion rates were analyzed.

RESULT(S)

A total of 1,582 embryos were thawed, of which 1,273 (80.5%) embryos were transferred and 1,032 (65.2%) embryos survived with > or = 50% intact blastomere. The embryo numbers with grade I or II before and after freezing and thawing were 1,110 (70.2%) and 790 (50.0%). The mean embryo numbers per transfer was 5.0. Twenty-eight pregnancies (11.4% per transfer) were established, which included 5 miscarriages, 1 ectopic pregnancy, 4 preterm and 18 term deliveries.

CONCLUSION(S)

Ultrarapid freezing is worthy of reconsideration for embryo cryopreservation.

Evolution of a cytokine using DNA family shuffling

DNA shuffling of a family of over 20 human interferon-alpha (Hu-IFN-alpha) genes was used to derive variants with increased antiviral and antiproliferation activities in murine cells. A clone with 135,000-fold improved specific activity over Hu-IFN-alpha2a was obtained in the first cycle of shuffling. After a second cycle of selective shuffling, the most active clone was improved 285,000-fold relative to Hu-IFN-alpha2a and 185-fold relative to Hu-IFN-alpha1. Remarkably, the three most active clones were more active than the native murine IFN-alphas. These chimeras are derived from up to five parental genes but contained no random point mutations. These results demonstrate that diverse cytokine gene families can be used as starting material to rapidly evolve cytokines that are more active, or have superior selectivity profiles, than native cytokine genes.

Prenatal diagnosis of thoracopelvic dysplasia. A case report

BACKGROUND

Thoracopelvic dysplasia, a variant of asphyxiating thoracic dysplasia (Jeune syndrome), is an uncommon skeletal disorder characterized by a small thorax, pelvic abnormalities and other complex, combined anomalies, including hypomelia, polydactyly and renal anomalies.

CASE

A 32-year-old woman, gravida 1, para 0, was referred at 27 weeks' gestation due to polyhydramnios. Sonography revealed hydramnios, low fetal thoracic circumference (TC) and abdominal circumference (AC) ratio (0.78), skull and skin edema, increased nuchal translucency (7 mm), micrognathia, low-set ears, left cardiac deviation (66 degrees), overriding fingers, and club and rock-buttock feet. Amniocentesis revealed a normal karyotype (46, XY). Asphyxiating thoracic dysplasia was considered. At 40 weeks' gestation, a male infant was delivered vaginally. Besides the prenatal findings, cryptorchidism and high-arched palate were noted. Radiography of the infant revealed a narrow, funnel-shaped thorax and small pelvis with short, flared iliac bones; poorly developed acetabulum; and small, shallow sciatic notch. No dyspnea was observed at five months postpartum.

CONCLUSION

Thoracopelvic dysplasia should be considered when a low TC/AC ratio (< 0.8) is observed. In this case the final diagnosis was made after detailed exclusion of other disorders combined with observation of a small thorax. Prenatal diagnosis of thoracopelvic dysplasia is possible.

Development of a set of equations describing joint trajectories during para-sagittal lifting

Given a lifting task with predetermined starting and ending positions, the angular trajectories are usually very consistent with a distinctive pattern. This paper derives a set of equations that can describe the joint trajectories during a para-sagittal lifting task. Three optimal motion patterns were also expressed by the polynomials: minimal hand jerk, minimal center of gravity (CG) jerk, and minimal muscle utilization rate (MUR). The variability of the joint movements were synthesized by overlapping the optimal patterns.

Twin vs. singleton pregnancy. Clinical characteristics and latency periods in preterm premature rupture of membranes

OBJECTIVE

To compare the clinical characteristics and latency periods (latencies) of preterm premature rupture of the membranes (PPROM) in twin vs. singleton pregnancy.

STUDY DESIGN

Between January 1986 and December 1996, data on all women with singleton and twin gestations complicated by PPROM were reviewed. Perinatal morbidity, mortality and latencies between singleton and twin pregnancies were compared. A further division according to PPROM at < 30 and > or = 30 weeks' gestation was made in both groups. Their latencies were compared.

RESULTS

A total of 131 singleton and 48 twin pregnancies with PPROM between 20 and 36 weeks' gestation were included in this series. Regardless of the gestational age at PPROM, the mean latencies of singleton and twin pregnancies were statistically similar (4.4 +/- 3.3 vs. 3.4 +/- 2.9 days, nonsignificant). When PPROM occurred at > or = 30 weeks, the latency of twin pregnancies was shorter than that of singleton pregnancies (2.5 +/- 1.9 vs. 3.7 +/- 2.6 days, P < .05). In both groups, the latencies of PPROM at < 30 weeks were longer than that at > or = 30 weeks (singleton, 5.6 +/- 4.0 vs. 3.7 +/- 2.6 days, P < .005; twin, 4.8 +/- 3.5 vs. 2.5 +/- 1.9 days, P < .05). We also observed a higher percentage of deliveries within the initial 48 hours in twin pregnancies: 50% of women delivered within 48 hours after PPROM and 91.7% within 7 days. In contrast, 26.7% and 85.5% of singleton pregnancies with PPROM were delivered within 48 hours and 7 days, respectively. Perinatal and neonatal outcomes in both groups were similar.

CONCLUSION

This investigation provides the basis for patient counseling and management in twin pregnancies with PPROM. In general, singleton and twin pregnancies with PPROM had similar latencies. Latency in PPROM at < 30 was longer than that of PPROM at > or = 30 weeks' gestation in both singleton and twin pregnancies. When PPROM occurred at < 30 weeks' gestation, both groups appeared to have similar latencies. In pregnancies with PPROM at > or = 30 weeks' gestation, latency in twins was shorter than in singleton pregnancies. In twin pregnancies with PPROM after 30 weeks' gestation, prompt steroid administration for fetal lung maturity should be considered.

Ultrastructural localization of hippocampal TNF-alpha immunoreactive cells in rats following transient global ischemia

Using a polyclonal antibody against rat TNF-alpha, we have identified specific intracellular immunoreactive sites in hippocampal pyramidal cells, astroglia, and in microglia within 72 h after a period of ischemia. Electron opaque immunoreactive products in pyramidal cells were found mainly in somata and dendrites. Astrocytes and microglia were nearly devoid of such complexes. These findings demonstrate the presence of TNF-alpha in hippocampal neurons and its enhancement by ischemic stress.

Hormonal profiles and immunological studies of male lupus in Taiwan

The aims of this study were to describe hormonal profiles, cytokine production and Fc-gamma receptor (Fcgamma-R) distribution in male lupus patients in Taiwan, and to look for any differences between our patients and normal individuals. Sixteen newly diagnosed and untreated male lupus patients were studied. Hormonal profiles were determined by radioimmunoassay. Interleukin-1 (IL-1) and IL-1 receptor antagonist (IL-1ra) production from both monocytes and neutrophils was determined by ELISA and murine thymocyte proliferation assay. The FcgammaR distribution on both monocytes and neutrophils was detected by flow cytometer. There were no significant differences in FSH, LH, testosterone, oestradiol, and beta-HCG blood levels in male lupus patients compared with normal individuals; however, the prolactin level in lupus patients was significantly higher than in normal individuals. Furthermore, there was no difference in IL-1 and IL-1ra production from both monocytes and neutrophils among male and female lupus patients, and normal individuals. Male lupus patients have a significantly lower FcgammaRII distribution on both monocytes and neutrophils when compared with female lupus patients and normal individuals. It was concluded that the high prolactin level and low FcgammaR distribution may play a role in the pathogenesis and prognosis of male lupus.

DNA-binding factors assemble in a sequence-specific manner on the maize mitochondrial atpA promoter

The maize mitochondrial atpA promoter has been well-characterized using in vitro transcription. The functional elements of this promoter comprise a central domain extending from -7 to +5 relative to the transcription start site, and an upstream domain of 1-3 bp that is purine-rich and centered around positions -11 to -12. As a first step in characterizing the transcriptional machinery, exonuclease-III mapping (toeprinting) was used to map the borders of DNA-protein interactions using either a 107-bp wild-type template or transcriptionally-inactive templates containing linker-scanning mutations. These experiments revealed that, with a wild-type promoter, protein factors occupy as much as 36 bp, from positions -20 to +16 relative to the transcription initiation site. Protein-binding patterns were altered when the linker-scanning mutants were used, suggesting that either the number or conformation of DNA-binding proteins could account for their inability to promote transcription initiation.

The prenatal diagnosis of Pierre-Robin sequence

The purpose of this study was to evaluate the spectrum of prenatal sonographic and chromosomal findings, associated anomalies and perinatal and neonatal outcomes in cases with Pierre-Robin sequence. All cases (20) with Pierre Robin sequence, who were born at China Medical College Hospital between 1990 and 1997, were included and analysed in this series. 12 pregnancies (60 per cent) were complicated by polyhydramnios and 9 (45 per cent) were combined with cleft palate. Four cases (20 per cent) with cardiac anomalies were also observed. Two fetuses (10 per cent) had abnormal karyotyping (one trisomy 21, one trisomy 18). All fetuses were delivered at or near term. Male deviation was observed in cases with isolated Pierre-Robin sequence or combined mild anomalies (male female ratio: 13:3). Two neonatal mortalities and three with mental retardation were observed. This investigation provides a basis for counselling patients with fetal micrognathia or neonatal Pierre-Robin sequence. The main prenatal sonographic findings of Pierre-Robin sequence are micrognathia, polyhydramnios and cleft palate. In cases of polyhydramnios, sonographic examination of the facial profile and palate are recommended. After the finding of polyhydramnios, micrognathia, and even cleft palate, clinicians should be aware of the possibility of neonatal Pierre-Robin sequence. Cardiac evaluation and karyotyping is also recommended.

Metabolic control of peroxisome abundance

Zellweger syndrome and related disorders represent a group of lethal, genetically heterogeneous diseases. These peroxisome biogenesis disorders (PBDs) are characterized by defective peroxisomal matrix protein import and comprise at least 10 complementation groups. The genes defective in seven of these groups and more than 90% of PBD patients are now known. Here we examine the distribution of peroxisomal membrane proteins in fibroblasts from PBD patients representing the seven complementation groups for which the mutant gene is known. Peroxisomes were detected in all PBD cells, indicating that the ability to form a minimal peroxisomal structure is not blocked in these mutants. We also observed that peroxisome abundance was reduced fivefold in PBD cells that are defective in the PEX1, PEX5, PEX12, PEX6, PEX10, and PEX2 genes. These cell lines all display a defect in the import of proteins with the type-1 peroxisomal targeting signal (PTS1). In contrast, peroxisome abundance was unaffected in cells that are mutated in PEX7 and are defective only in the import of proteins with the type-2 peroxisomal targeting signal. Interestingly, a fivefold reduction in peroxisome abundance was also observed for cells lacking either of two PTS1-targeted peroxisomal beta-oxidation enzymes, acyl-CoA oxidase and 2-enoyl-CoA hydratase/D-3-hydroxyacyl-CoA dehydrogenase. These results indicate that reduced peroxisome abundance in PBD cells may be caused by their inability to import these PTS1-containing enzymes. Furthermore, the fact that peroxisome abundance is influenced by peroxisomal 105-oxidation activities suggests that there may be metabolic control of peroxisome abundance.

Functional analysis of two maize cDNAs encoding T7-like RNA polymerases

We have characterized two maize cDNAs, rpoTm and rpoTp, that encode putative T7-like RNA polymerases. In vivo cellular localization experiments using transient expression of the green fluorescent protein suggest that their encoded proteins are targeted exclusively to mitochondria and plastids, respectively. An antibody raised against the C terminus of the rpoTp gene product identified mitochondrial polypeptides of approximately 100 kD. Their presence was correlated with RNA polymerase activity, and the antibody inhibited mitochondrial in vitro transcription activity. Together, these results strongly suggest that the product of rpoTm is involved in maize mitochondrial transcription. By contrast, immunoblot analysis and an antibody-linked polymerase assay indicated that rpoTp specifies a plastid RNA polymerase component. A quantitative reverse transcription-polymerase chain reaction assay was used to study the transcription of rpoTp and rpoTm in different tissues and under different environmental conditions. Although both genes were constitutively expressed, rpoTm transcripts were generally more prevalent in nonphotosynthetic tissues, whereas an increase in rpoTp transcripts paralleled chloroplast development. We suggest that these two genes encode constitutive components of the organelle transcription machinery but that their expression is nonetheless subject to modulation during plant development.

Elliptocytes and tailed poikilocytes correlate with severity of iron-deficiency anemia

This study examines the relationships between abnormal RBC morphology, RBC indices measured with an automated hematology analyzer, serum iron studies, and severity of anemia in patients with findings indicative of iron-deficiency anemia. Counts and morphologic classification of 1,000 RBCs from each of 22 patients were performed, and correlations were determined between parameters. The Student t test was used to determine the level of significance for correlations between parameters. Several significant relationships were found. As the percentage of elliptocytes increased, hemoglobin concentration, hematocrit, RBC concentration, and mean corpuscular hemoglobin level decreased (r = .48, .44, .40, and .49, respectively; P < .05). As the percentage of tailed poikilocytes increased, hemoglobin concentration, hematocrit, and RBC concentration decreased (r = .70, .77, and .71, respectively; P < .01) and RBC distribution width increased (r = .73; P < .01). Of significance, serum ferritin levels, long considered the best single indicator of iron deficiency, showed no correlation with the morphologic abnormalities assessed, severity of anemia, or any of the analyzer-generated indices. Our results indicate that microscopic evaluation of RBC morphology remains an important tool for the pathologist to evaluate the severity of anemia in patients with iron deficiency.

Human acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) gene organization and evidence that the 4.3-kilobase ACAT-1 mRNA is produced from two different chromosomes

Acyl-CoA:cholesterol acyltransferase (ACAT) plays important roles in cellular cholesterol homeostasis. Four human ACAT-1 mRNAs (7.0, 4.3, 3.6, and 2.8 kilobases (kb)) share the same short 5'-untranslated region (exon 1) and coding sequence (exons 2-15). The 4.3-kb mRNA contains an additional 5'-untranslated region (1289 nucleotides in length; exons Xa and Xb) immediately upstream from the exon 1 sequence. One ACAT-1 genomic DNA insert covers exons 1-16 and a promoter (the P1 promoter). A separate insert covers exon Xa (1277 base pairs) and a different promoter (the P7 promoter). Gene mapping shows that exons 1-16 and the P1 promoter sequences are located in chromosome 1, while exon Xa and the P7 promoter sequence are located in chromosome 7. RNase protection assays demonstrate three different protected fragments, corresponding to the 4.3-kb mRNA and the two other mRNAs transcribed from the two promoters. These results are consistent with the interpretation that the 4.3-kb mRNA is produced from two different chromosomes, by a novel RNA recombination mechanism involving trans-splicing of two discontinuous precursor RNAs.

Recombinant human leukemia inhibitory factor enhances the development of preimplantation mouse embryo in vitro

OBJECTIVE

To assess the effect of recombinant human leukemia inhibitory factor (rhLIF) on mouse embryos in vitro.

DESIGN

Controlled prospective study.

SETTING

Academic research environment.

ANIMAL(S)

Female CB6F1 mice between 6 and 8 weeks old.

INTERVENTION(S)

Mice were divided randomly into three groups, which included a control group in an in vivo study (group I) and two groups in an in vitro study (groups II and III). Mice were killed at 116-120 hours (group I) and 44-48 hours (groups II and III) after hCG injection. Two-cell embryos (groups II and III) and blastocysts (group I) were obtained. Embryos in group II were cocultured with human tubal fluid (HTF) + 0.5% human serum albumin and in group III with HTF + rhLIF (1,000 U/mL) under paraffin oil.

MAIN OUTCOME MEASURE(S)

The embryonic numbers in different stages were recorded and compared.

RESULT(S)

Similar early embryo development to the four- to eight-cell and morula stages was noted between groups II and III (87.3% versus 91.0% and 74.6% versus 87.1%, respectively). However, further embryo development to the blastocyst, expanded blastocyst, and hatching blastocyst in group II (48.1%, 31.7%, and 18.5%, respectively) was lower than that in group III (83.6%, 53.7%, and 37.8%).

CONCLUSION(S)

RhLIF does not provide obvious stimulation in the early mouse embryo. However, rhLIF has positive effects on preimplantation blastocyst growth, differentiation, and hatching.

Bartonella henselae and Bartonella clarridgeiae infection in domestic cats from The Philippines

One hundred seven domestic cats from The Philippines were serologically tested to establish the prevalence of Bartonella infection. A subset of 31 of these cats also had whole blood collected to tentatively isolate Bartonella strains. Bartonella henselae and B. clarridgeiae were isolated from 19 (61%) of these cats. Bartonella henselae type I was isolated from 17 (89%) of the 19 culture-positive cats. Six cats (31%) were infected with B. clarridgeiae, of which four were coinfected with B. henselae. Sixty-eight percent (73 of 107) and 65% (70 of 107) of the cats had antibodies to B. henselae and B. clarridgeiae, respectively, detected by an immunofluorescence antibody (IFA) test at a titer > or = 1:64. When tested by enzyme immunoassay (EIA), 67 cats (62.6%) had antibodies to B. henselae and 71 cats (66.4%) had antibodies to B. clarridgeiae. Compared with the IFA test, the B. henselae EIA had a sensitivity of 90.4% and a specificity of 97%, with positive and negative predictive values of 98.5% and 82.5%, respectively. Similarly, the B. clarridgeiae EIA had a sensitivity of 97% and a specificity of 92% specificity, with positive and negative predictive values of 95.8% and 94.4%, respectively. The presence of antibodies to Bartonella was strongly associated with flea infestation. Domestic cats represent a large reservoir of Bartonella infection in the Philippines.

A comparison of various ultrasound technologies

Ultrasound-assisted lipoplasty represents a new and exciting adjunct to traditional suction-assisted lipoplasty techniques. With the development of this new field, a variety of special equipment needs have arisen. Most important among these needs are the ultrasonic generator, handpiece, and probe. This article critically examines, compares, and contrasts some of the most popular technological equipment currently available.

Function and sequence analyses of tumor suppressor gene p53 of CHO.K1 cells

The tumor suppressor gene p53 plays an important role in guarding genomic integrity. When induced in response to environmental results, the gene product of p53 functions as a transcription factor to transactivate genes involved in arresting the cell cycle and as a facilitator of DNA repair. In contrast, the status of p53 in Chinese hamster ovary (CHO) cells, commonly used as a model system for various studies including those involving the cell cycle and transformation, remains an enigma. In this study, the function and sequence of p53 in CHO.K1 cells were investigated. The level of p53 proteins was elevated on ultraviolet (UV) irradiation of the cells, and the proteins formed specific complexes as probed with DNA containing p53-binding sequences. Its activities toward responsive promoters were inducible by UV in a dose-dependent manner. Although p53 in CHO.K1 contained a single missense mutation at codon 211, the mutation apparently had no effect on the functional properties of the protein. The CHO.K1 cells on X-ray irradiation failed to arrest at G1 phase even when the cells were transfected with a wildtype human p53 gene, indicating that the failure probably was not caused by dysfunction of its p53, but by some other mechanism. This result is consistent with the finding that p21(Waf1/Cip1) is undetectable in UV-treated CHO.K1 cells, whereas Gadd45 is induced by UV light in the cells.

Prenatal diagnosis of dyssegmental dysplasia. A case report

BACKGROUND

Since the first use of sonography, most fetal dwarfism has been detectable prenatally. The correct differentiation of the subtype of dwarfism is difficult at times. Dyssegmental dysplasia is probably an exception to these subtypes because the vertebral disorganization and occipital encephalocele at times permits prenatal diagnosis.

CASE

A 34-year-old woman, gravida 3, para 1, elective abortion 1 for dwarfism, was referred at 27 weeks' gestation for cystic hygroma. Further sonographic findings included: cystic hygroma with massive ascites, micromelia, occipital encephalocele, spinal disorganization and hydramnios. The fetus and both parents appeared to have a normal karyotype. Later the pregnancy was terminated with vaginal delivery. The fetus had micromelia, camptomelia, cystic hygroma, a flat face, short neck, short trunk, narrow thorax with protuberant abdomen, scoliosis and clubfeet.

CONCLUSION

Sonography is effective in prenatal diagnosis of dyssegmental dysplasia. With sonography, diagnosis of dyssegmental dysplasia becomes possible as early as the first trimester.

Severe intrahepatic cholestasis caused by amiodarone toxicity after withdrawal of the drug: a case report and review of the literature

Cholestasis has been reported as a rare presentation among patients with severe liver injury secondary to amiodarone hepatic toxicity. We report an unusual case of amiodarone-induced cholestatic hepatotoxicity occurring after amiodarone had been discontinued and the initial abnormal liver function findings had improved. The patient, without jaundice at the initial presentation, developed severe jaundice about 4 months after withdrawal of amiodarone. Light and transmission electron microscopic examination of a specimen secured by computed tomographically guided liver biopsy was consistent with amiodarone hepatic toxicity as the cause of intrahepatic cholestasis. An abdominal ultrasound, endoscopic retrograde cholangiography, and dimethyl iminodiacetic acid and computed tomographic scans of the abdomen all failed to demonstrate any other causes for jaundice other than amiodarone toxicity. Thus, amiodarone hepatic toxicity may occur after drug withdrawal even if results of liver function tests improve. Histopathologic examination of a liver biopsy specimen is of value for diagnosis and prognosis. The liver biopsy findings, clinical course, and liver function test results are discussed, and the English-language literature on amiodarone cholestatic hepatotoxicity is reviewed.

Leukocyte spreading behavior on vascular biomaterial surfaces: consequences of chemoattractant stimulation

Chemoattractant-induced phenomena of polarity and migration of polymorphonuclear leukocytes (PMN) are believed to play a key physiological role in controlling bacterial infections on implantable vascular biomaterials. Our study targeted the spreading behavior of human PMN adherent to expanded polytetrafluoroethylene (ePTFE), pretreated with various plasma proteins, in response to the chemoattractant, N-formyl-methionyl-leucyl-phenylalanine (fMLP). To this end, a novel imaging configuration was developed to allow in situ reconstructive analysis of PMN 3-D morphology on opaque ePTFE surfaces, using optical sectioning confocal microscopy. Following fMLP stimulation, PMN morphological polarity was enhanced on all substrates studied except fibrinogen treated ePTFE. 3-D PMN morphometry revealed that in the absence of fMLP, overall cell spreading was minimized on albumin-treated ePTFE and maximized on fibrinogen and immunoglobulin-G-treated ePTFE. Following fMLP stimulation, overall PMN spreading increased markedly on untreated and albumin-coated ePTFE, while it stayed invariant on IgG and plasma treated ePTFE, and decreased on fibrinogen-treated ePTFE. Spatial analysis of PMN spreading following fMLP stimulation revealed enhanced PMN attachment on untreated and albumin treated ePTFE and diminished attachment on fibrinogen and plasma treated ePTFE. Thus, chemoattractant stimulation altered a wide range of PMN spreading attributes on ePTFE, including morphological polarity, substrate attachment, and 3-D membrane spreading, in a substrate dependent manner. These chemoattractant-induced spreading responses may also have important consequences for PMN phagocytosis. We report that fMLP stimulation led to enhanced unopsonized particulate phagocytosis on untreated and albumin treated ePTFE, but caused no discernible change in phagocytosis on other protein substrates. Thus, chemoattractant modulation of PMN spreading on ePTFE is highly substrate-regulated, and manifests in concerted effects on PMN phagocytosis.

Cerebral blood flow in patients with normal pressure hydrocephalus

Mean cerebral blood flow (CBF) of the whole brain was measured in 48 patients who underwent cerebrospinal fluid shunt surgery for normal pressure hydrocephalus (NPH) by performing first-pass radionuclide angiography using 99Tcm-hexamethylpropylene amine oxime. Patients were divided according to outcome into an 'excellent' improvement group, a 'good' improvement group, a 'fair' improvement group and a 'poor' improvement group. Patients with excellent and good improvement had a preoperative mean CBF of 40.4 +/- 3.9 ml.100 g-1.min-1 and 37.1 +/- 5.5 ml.100 g-1.min-1, respectively, both of which were significantly (P < 0.005) higher than that in 11 patients who showed fair improvement (30.8 +/- 3.2 ml.100 g-1.min-1) and six patients who showed poor improvement (31.8 +/- 2.5 ml.100 g-1.min-1). Patients with a clinical improvement after shunting had an increased postoperative mean CBF. We conclude that patients with a preoperative mean CBF of over 35 ml.100 g-1.min-1 can show favourable improvement after a shunting procedure, and that the preoperative mean CBF of 32 ml.100 g-1.min-1 can be considered the critical level for treatment.

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.

Disulfide isomers of alpha-neurotoxins from King cobra (Ophiophagus hannah) venom

Two novel alpha-neurotoxins, Oh-6A and Oh-6B, isolated from the king cobra (Ophiophagus hannah) venom, consist of 70 amino acid residues with 10 cysteine residues and share the same amino acid sequences as determined by Edman degradation on the peptide fragments generated from the proteolytic hydrolysates. Their sequences share 46-53% homology with Oh-4, Oh-5, Toxin a, and Toxin b from the same venom. The finding that Oh-6A and Oh-6B had different retention times in the reversed-phase column suggested that the two toxin molecules should not have the same conformation. Selective reduction on the disulfide bond, Cys26--Cys30, at the tip of their loop II structures resulted in the production of the partially reduced derivatives eluted at the same position. Under redox conditions, the partially reduced Oh-6A and 6B exclusively converted into native Oh-6A as evidenced by HPLC analyses. This suggests that Oh-6A and Oh-6B are disulfide isomers which probably arise from cis-trans isomerization of the Cys26--Cys30 disulfide bond. Alternatively, the two toxins exhibited binding activity toward nAChR and lethal toxicity equally. It reflects that the diversity around the extra loop at the loop II structure does not exert a significant effect on the manifestation of the neurotoxicity of Oh-6A and Oh-6B.

Expression of soluble human signaling lymphocytic activation molecule in vivo

BACKGROUND

Signaling lymphocytic activation molecule (SLAM) is a novel glycoprotein expressed on activated T and B cells. Ligation of cell surface SLAM, either by anti-SLAM mAbs or the recombinant soluble form of SLAM (sSLAM), enhanced the proliferation of T and B cells in vitro. In addition, the engagement of SLAM on T cells preferentially induced IFN-gamma production even by allergen-specific TH2 clones.

OBJECTIVE

In this study we investigated the expression of sSLAM in vivo in healthy individuals and in disease conditions that are associated with increased TH1 - or TH2 -cell responses.

METHODS

The expression of mRNA encoding sSLAM in peripheral blood and synovial fluid (SF) lymphocytes was studied by using reverse transcriptase-PCR, and the presence of sSLAM protein in serum and SF samples was investigated by using a specific ELISA.

RESULTS

Lymphocytes from patients with rheumatoid arthritis (RA) and healthy individuals consistently expressed mRNA encoding sSLAM. In addition, sSLAM protein was present in 38% of serum and 54% of SF samples from patients with RA and in 47% of serum samples from healthy individuals. The levels of sSLAM in positive serum and SF samples from patients with RA and in positive serum samples from healthy individuals were not significantly different. In contrast, the levels of sSLAM were significantly lower in patients with reactive arthritis or in patients with elevated IgE levels than in patients with RA. Similarly, the frequency of positive SF samples was significantly lower in reactive arthritis (28%) than in RA (54%).

CONCLUSION

These results indicate that sSLAM is present in serum and SF, further suggesting that sSLAM regulates T- and B-cell function in vivo. Moreover, these data suggest an association between low sSLAM production and the occurrence of TH2 responses in vivo.

Epigenetic toxicology as toxicant-induced changes in intracellular signalling leading to altered gap junctional intercellular communication

Communication mechanisms [extra-, intra-, and gap junctional inter-cellular communication (GJIC)] control, from the fertilized egg, through embryogenesis to maturity and aging, whether a cell proliferates, differentiates, dies by apoptosis, or if differentiated, adaptively responds to endogenous and exogenous signals. From the egg to the 100 trillion cells in the human body, health is maintained when these communication processes between stem, progenitor and terminally differentiated cells are integrated. Each cell choice involves 'epigenetic' mechanisms to alter the expression of genes at the transcriptional, translational or post-translational levels. Disruption of the communication mechanisms can be either adaptive or maladaptive. Modulation of extra-cellular communication, either by genetic imbalances of growth factors, hormones or neurotransmitters or by environmental, exogenous chemicals can trigger signal transducing intra-cellular mechanisms. These intra-cellular signals can modulate gene expression at the transcriptional, translational or post-translational levels while also modulating GJIC. Untimely or chronic disruption of GJIC during embryonic or fetal development could lead to embryonic lethality or teratogenesis. By modulation of GJIC, homeostatic control of cell growth, differentiation or apoptosis could lead to specific diseases, such as neurological, cardiovascular, reproductive or endocrinological dysfunction. Chemical modulation or oncogene down-regulation of GJIC in initiated tissues has been shown to lead to tumor promotion. Genetic syndromes carrying a mutated gap junction gene, together with some transgenic and knock-out gap junction gene mice, provide evidence for the importance of this organelle found only in metazoans. Implications for 'thresholds' to toxicants and for risk assessment are evident.

Recombinant acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) purified to essential homogeneity utilizes cholesterol in mixed micelles or in vesicles in a highly cooperative manner

Acyl-coenzyme A:cholesterol acyltransferase (ACAT) is an integral membrane protein located in the endoplasmic reticulum. It catalyzes the formation of cholesteryl esters from cholesterol and long-chain fatty acyl coenzyme A. The first gene encoding the enzyme, designated as ACAT-1, was identified in 1993 through an expression cloning approach. We isolated a Chinese hamster ovary cell line that stably expresses the recombinant human ACAT-1 protein bearing an N-terminal hexahistidine tag. We purified this enzyme approximately 7000-fold from crude cell extracts by first solubilizing the cell membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, then proceeding with an ACAT-1 monoclonal antibody affinity column and an immobilized metal affinity column. The final preparation is enzymologically active and migrates as a single band at 54 kDa on SDS-polyacrylamide gel electrophoresis. Pure ACAT-1 dispersed in mixed micelles containing sodium taurocholate, phosphatidylcholine, and cholesterol remains catalytically active. The cholesterol substrate saturation curves of the enzyme assayed either in mixed micelles or in reconstituted vesicles are both highly sigmoidal. The oleoyl-coenzyme A substrate saturation curves of the enzyme assayed under the same conditions are both hyperbolic. These results support the hypothesis that ACAT is an allosteric enzyme regulated by cholesterol.

Genetic characterization of the mRNAs encoding alpha-bungarotoxin: isoforms and RNA editing in Bungarus multicinctus gland cells

The mRNA encoding alpha-bungarotoxin (alpha-Butx) was prepared from the venom glands of Bungarus multicinctus by Cap-finder cDNA synthesis. The sequences of the 3'- and 5'-flanking regions including a signal peptide of alpha-Butx were almost identical with those of Elapidae and Hydrophiidae toxins, suggesting that they may have the same origin. Sixteen polymorphic mRNA sequences of alpha-Butx were detected from B.multicinctus gland cells. Analysis of the genomic DNA of alpha-Butx indicated that the polymorphic mRNA originated from one DNA sequence. Most of the mutations in alpha-Butx mRNA were silent and the hot-spot variations occurred at 78, 107, 129, 198 and 201 nt in alpha-Butx mRNA. Ten distinct protein sequences of alpha-Butx could be deduced from the polymorphic mRNA and one of the isoforms has already been isolated. Since alpha-Butx DNA is a single copy in the genome, the RNA polymorphism might result from post-transcriptional editing. These results indicate that the authentic alpha-Butx is in fact derived from edited mRNAs. RNA editing may contribute a common mechanism toward the diversity of alpha-neurotoxins in snake glands.

Induction of apoptosis and down-regulation of bcl-6 in mutu I cells treated with ethanolic extracts of the Chinese herbal supplement PC-SPES

PC-SPES, an HPLC-standardized 8-herb dietary supplement prepared by proprietary extraction/mixing technologies, appears to have a number of health benefits when given to cancer patients. These include reduction of serum PSA (prostate specific antigen) in individuals diagnosed with advanced prostate carcinoma, and overall improvement of morbidity and immune status in terminal cancer cases. Since the expression of bcl-6 in T and B lymphocytes has been reported to be significantly down regulated by mitogens, we reason that the immune boosting effects of PC-SPES could involve the modulation of bcl-6 expression. Such a hypothesis was tested in the bcl-6 abundant Mutu I cells. Specifically, we investigated the effects of PC-SPES in regulating cell growth, induction of apoptosis, effecting changes in the retinoblastoma gene RB and the modulation of expression of the bcl-6. Herein we report that proliferation of Mutu I cells was inhibited by a 3-7 day incubation with ethanolic extracts of PC-SPES, with concurrent induction of apoptosis. In addition, a dose-dependent reduction of bcl-6 was observed, with no concomitant change in either the phosphorylated or the unphosphorylated forms of RB. These data raise the possibility that PC-SPES may enhance immune functions in vivo by down-regulating bcl-6 expression. Alternatively, decrease in bcl-6 could serve as a biomarker for testing the efficaciousness of PC-SPES in vivo.

Evaluation of intrinsic modulation of synaptic transmission by ATP in mouse fast twitch muscle

This study aims to evaluate whether endogenous ATP or adenosine modulates the neurotransmission and contractile function of mouse phrenic nerve-diaphragm. Bath application of ATP (1 mM) and alpha, beta-methylene ATP (m-ATP, 0.1 mM) elevated muscle tones, depressed contractions (approximately 12%), and depolarized muscle membranes (approximately 20 mV). Adenosine (1 mM) or low concentrations of ATP (0.1 mM) had no effect. In a low Ca2+ media, ATP caused prolonged inhibitions of endplate potentials (EPPs), whereas m-ATP augmented EPPs while both agents produced slight effects in normal Tyrode solution. When applied by puff ejection, ATP and m-ATP additionally elicited fast transient suppressions of EPPs in association with inhibitions of high K+-evoked releases of miniature EPPs. Blockades of P2 purinoceptors with suramin antagonized all the effects of ATP and m-ATP except the prolonged inhibitions of EPPs induced by ATP, which were antagonized instead by 8-cyclopentyl-1,3-dipropylxanthine (CPDPX), an A1 adenosine receptor antagonist. Suramin and CPDPX did not change contractions nor alter EPPs evoked by a low- or high-frequency nerve stimulation. The results indicate that exogenously applied ATP and m-ATP, via activations of distinct pre- and postsynaptic purinoceptors, exert inhibitory and facilitatory pharmacological modulations on the mature neuromuscular junction. However, because of intrinsic high efficiency of the synaptic transmission under physiological conditions, endogenously released ATP and its degradation product-adenosine-do not build up to concentrations high enough to alter motor functions.

Phenotype-genotype relationships in complementation group 3 of the peroxisome-biogenesis disorders

The peroxisome-biogenesis disorders (PBDs) are a set of often lethal genetic diseases characterized by mental retardation and defective peroxisomal matrix protein import. Mutations in PEX12 are known to underlie the disease in two patients from complementation group 3 of the PBDs. Here we show that all patients from this group carry mutations on both alleles of PEX12. A comparison between PEX12 genotypes and the clinical and cellular phenotypes of the corresponding PBD patients suggests a relatively straightforward relationship between genotype and phenotype in this group of the PBDs, such that the loss of PEX12 function leads to more-severe cellular and clinical phenotypes. However, one patient who presented relatively mild clinical and cellular phenotypes was a compound heterozygote for two seemingly severe mutations on each PEX12 allele. PEX12 mRNA present in the patient's cells was derived from only one allele, the one that carried a 2-bp deletion early in the PEX12 coding region, c.26,27Delta. The deduced protein product of this mRNA would contain only the first eight amino acids of the protein, and yet this mutant PEX12 cDNA displayed significant PEX12 activity in a functional complementation assay. Surprisingly, the PEX12/c.26, 27Delta cDNA directed the synthesis of a 29-kD PEX12 protein in vitro, a result that is consistent with translation initiation at a downstream AUG codon. Transfection studies confirmed the expression of similarly sized PEX12 proteins from the PEX12/c.26,27Delta allele. Thus, it appears that translation initiation at internal AUG codons may modulate disease phenotypes and should be considered whenever unexpectedly mild phenotypes result from severe mutations early in the coding region.

The clinical features and prognosis of male lupus in Taiwan

Our objective was to describe the clinical manifestations, laboratory data, and prognosis in male Chinese lupus patients in Taiwan. Seventy-two male lupus patients, diagnosed and followed in Tri-Service General Hospital between 1983 and 1996, were studied and their clinical data analyzed, retrospectively. The mean age at diagnosis was 34+/-16 y (mean+/-s.d., range: 13-82 y). The peak incidence of age at diagnosis was between 13 and 40 years. The three most frequent clinical manifestations were renal disease, 75%; malar rash, 61%; and arthritis, 53%. The three most frequent abnormal laboratory findings were anti-nuclear antibodies (ANA), 97%; hypocomplementemia, 76%; and anti-ds DNA, 57%. The 1-, 5-, and 10-year survival rates were 85%, 76%, and 75%, respectively. In summary, a higher frequency of renal disease, malar rash and photosensitivity, but a lower frequency of arthritis and lymphadenopathy were demonstrated in our 72 ethnic Chinese male Taiwanese lupus patients compared to previous reports of Caucasians. The prognosis seems to be similar to that of both Chinese and Caucasian males but seems to be poor when compared to either Chinese or Caucasian female lupus patients.

Primary hyperparathyroidism in pregnancy--report of 3 cases

Three cases of primary hyperparathyroidism in pregnancy are described. Patient 1 developed left thigh pain and lower abdominal pain at 34 weeks' gestation. Patient 2 had right flank pain and lower abdominal pain at 32 weeks' gestation. Both patients accepted medical therapy initially, which resulted in poor control of hypercalcemia. Patient 1 delayed her parathyroidectomy until the postpartum period; she had maternal hypercalcemia and neonatal hypocalcemia. Patient 2 accepted parathyroidectomy at 32 weeks' gestation with an uneventful outcome for both mother and baby. Patient 3 was asymptomatic; her hyperparathyroidism was diagnosed postpartum after neonatal hypocalcemia and agreed to parathyroidectomy. All 3 patients had a parathyroid adenoma.

Homologous protection but lack of heterologous-protection by various species and types of Bartonella in specific pathogen-free cats

Cat-scratch disease (CSD) is caused by Bartonella henselae, and possibly by B. clarridgeiae. In immuno-compromised persons, B. henselae is one of the agents causing bacillary angiomatosis. Domestic cats are the main reservoir of these bacteria, which are transmitted primarily from cat to cat by fleas. Possible strategies to prevent the spread of infection among cats are to eliminate flea infestation or to prophylactically immunize cats. In order to develop an appropriate vaccine, it is important to determine if cats become resistant to re-infection by the same strain or various types or species of Bartonella. In a series of experiments, 21 SPF cats were experimentally infected by the intradermal route with 10(5)-10(10) colony-forming units/ml of either B. henselae type II (17 cats), or a new strain 'Humboldt' isolated from a mountain lion (4 cats). The cats were bled weekly to every other week for determination of bacteremia and specific antibody production. After they cleared their infection, they were challenged by a homologous or heterologous strain of Bartonella: 10 cats were challenged with B. henselae type II, three cats with B. henselae type I, four cats with B. clarridgeiae and four cats with the 'Humboldt' strain. Seven of these cats received a third inoculum dose resulting in three cats sequentially infected with sequence B. henselae type II/B. henselae type II/'Humboldt', two cats with sequence B. henselae type II/'Humboldt'/B. clarridgeiae, and two cats with the sequence 'Humboldt'/B. henselae type II/'Humboldt'. All cats challenged with a homologous strain remained abacteremic after challenge and had an increased IgG antibody titer. All cats challenged with either a different Bartonella species or type became bacteremic. The few cats receiving a third inoculum with a strain homologous to the initial strain remained abacteremicafter that challenge. All cats infected with B. clarridgeiae suffered relapsing bacteremia compared to only 36% of the B. henselae infected cats and 22% of the 'Humboldt'-infected cats (p=0.008). The duration of bacteremia was significantly longer in B. henselae primary-infected cats (mean: 34 weeks) than B. henselae heterologously challenged cats (mean: 9 weeks) (p=0.014). These data clearly indicate the lack of cross-protection between B. henselae and B. clarridgeiae and furthermore, indicate the lack of protection between B. henselae types I and II, and a wildlife isolate. A vaccine strategy for CSD prevention in domestic cats will require a multivalent vaccine approach.

Identification of arg-30 as the essential residue for the enzymatic activity of Taiwan cobra phospholipase A2

Taiwan cobra (Naja naja atra) phospholipase A2 (PLA2) was inactivated by arginine-specific reagents, phenylglyoxal and 1, 2-cyclohexanedione. Kinetic analyses of the modification reaction revealed that the inactivation of PLA2 followed pseudo-first-order kinetics and the loss of activity was correlated with the incorporation of one molecule of modification reagent per PLA2 molecule. This was confirmed by the results of amino acid composition determination, that showed that a marked decrease in enzymatic activity was associated with the modification of one arginine residue. Tryptic cleavage of the modified protein and microsequencing revealed that Arg-30 was the functionally essential residue. The incorporation of a modifier into the PLA2 did not significantly affect the secondary structure of the enzyme, as revealed by the CD spectrum, and Ca2+-binding of the modified PLA2 was unaffected. Nevertheless, the nonpolarity of the active site of PLA2 markedly decreased with the arginine modification, as evidenced by the decreases in the enhancement of Trp and 8-anilinonaphthalene sulfonate fluorescence. These results, together with those of X-ray crystallographic analysis of N. naja atra PLA2 [Scott et al. (1990) Science 250, 1541-1546], demonstrate that Arg-30 is one of the residues involved in the interfacial binding of a PLA2 molecule with its substrate.