Cosegregation of single genes associated with fertility restoration and transcript processing of sorghum mitochondrial orf107 and urf209

Defective nuclear-cytoplasmic interactions leading to aberrant microgametogenesis in sorghum carrying the IS1112C male-sterile cytoplasm occur very late in pollen maturation. Amelioration of this condition, the restoration of pollen viability, involves a novel two-gene gametophytic system, wherein genes designated Rf3 and Rf4 are required for viability of individual gametes. Rf3 is tightly linked to, or represents, a single gene that regulates a transcript processing activity that cleaves transcripts of orf107, a chimeric mitochondrial open reading frame specific to IS1112C. The mitochondrial gene urf209 is also subject to nucleus-specific enhanced transcript processing, 5' to the gene, conferred by a single dominant gene designated Mmt1. Examinations of transcript patterns in F2 and two backcross populations indicated cosegregation of the augmented orf107 and urf209 processing activities in IS1112C. Several sorghum lines that do not restore fertility or confer orf107 transcript processing do exhibit urf209 transcript processing, indicating that the activities are distinguishable. We conclude that the nuclear gene(s) conferring enhanced orf107 and urf209 processing activities are tightly linked in IS1112C. Alternatively, the similarity in apparent regulatory action of the genes may indicate allelic differences wherein the IS1112C Rf3 allele may differ from alleles of maintainer lines by the capability to regulate both orf107 and urf209 processing activities.

Experimental simian varicella virus infection of St. Kitts vervet monkeys

Experimental simian varicella virus (SVV) infection of St. Kitts vervet monkeys was evaluated as an animal model to investigate human varicella-zoster virus (VZV) infections. During the incubation period, viremia disseminated infectious virus throughout the body via infected peripheral blood lymphocytes (PBLs). A vesicular skin rash in the inguinal area, and on the abdomen, extremities, and face appeared on day 7-10 postinfection. Necrosis and hemorrhage in lung and liver tissues from acutely infected monkeys were evident upon histologic analysis. Recovery from simian varicella was accompanied by a rise in the serum neutralizing antibody response to the virus. SVV latency was established in trigeminal ganglia of monkeys which resolved the acute infection. This study indicates that experimental SVV infection of St. Kitts vervets is a useful animal model to investigate SVV and VZV pathogenesis and to evaluate potential antiviral agents and vaccines.

Hypocalcemic stimulation and nonselective venous sampling for localizing parathyroid adenomas: work in progress

PURPOSE

To evaluate whether the release of parathyroid hormone (PTH) from parathyroid tumors during selective parathyroid arteriography can help localize the tumors.

MATERIALS AND METHODS

In 20 patients (six men, 14 women; age range, 24-72 years) with parathyroid tumors undergoing parathyroid arteriography after failed surgery, serial measurements of PTH were obtained during selective arteriography with nonionic contrast material. PTH levels were measured in the superior vena cava (SVC) before and at varying times from 20 to 120 seconds after arteriography.

RESULTS

A 1.4-fold increase in the PTH level of the postarteriographic SVC samples enabled correct prediction of the site of adenoma in 13 of the 20 patients (65%). Of nine patients with positive arteriograms, eight had positive results of postarteriographic sampling. Of 11 patients with negative arteriograms, five had positive results of postarteriographic sampling.

CONCLUSION

Sampling the SVC for PTH gradients after selective parathyroid arteriography correctly indicated the site of the adenoma in 13 of 20 patients (65%).

Increased glutamatergic neurotransmission and oxidative stress after alcohol withdrawal

OBJECTIVE

Neurophysiological and pathological effects of ethanol may be mediated, to an important extent, via the glutamatergic system. Animal studies indicate the acute effects of ethanol disrupt glutamatergic neurotransmission by inhibiting the response of the N-methyl-D-aspartate (NMDA) receptor. Persistent attenuation of glutamatergic neurotransmission by chronic ethanol exposure results in the compensatory up-regulation of NMDA receptors. Whether glutamatergic neurotransmission and oxidative stress are enhanced during ethanol withdrawal in humans is unknown.

METHOD

CSF was obtained from 18 matched comparison subjects and from 18 patients with alcohol dependence 1 week and 1 month after cessation of ethanol ingestion. CSF samples were analyzed for excitatory neurotransmitters, gamma-aminobutyric acid (GABA), and markers for oxidative stress.

RESULTS

The alcohol-dependent patients' CSF levels of aspartate, glycine, and N-acetylaspartylglutamate were all higher than those of the comparison subjects, and their concentration of GABA was lower. In addition, there were significant correlations between excitatory neurotransmitters and oxidative stress markers, which suggest that the two mechanisms may play an interactive role in neurotoxicity mediated by ethanol withdrawal.

CONCLUSIONS

The data suggest that augmentation of excitatory neurotransmission may lead to enhanced oxidative stress, which, in concert with reduced inhibitory neurotransmission, may contribute to the symptoms of ethanol withdrawal and associated neurotoxicity in humans. Whether these abnormalities represent a trait- or state-dependent marker of ethanol dependence remains to be resolved.

Analysis of binding and membrane destabilization of phospholipid membranes by surfactant apoprotein B

To further elucidate the nature of the molecular interactions of surfactant apoprotein B (SP-B) with phospholipid (PL) membranes, we studied the binding of SP-B to PL membranes and the lipid-dependency of its subsequent effects on leakage and fusion of membranes. SP-B binding to membranes was studied by labeling the protein with the fluorophore 7-nitro-2,1,3-benzoxadiazol-4-yl (NBD) and measuring the fluorescence of the labeled protein in the presence of varying amounts of dipalmitoylphosphatidylcholine-egg phosphatidylglycerol (DPPC-eggPG; 7-3). Leakage of contents from liposomes made of DPPC and varying molar fraction of egg phosphatidylcholine (eggPC) or eggPG was assessed by measuring the fluorescence of entrapped water-soluble probes ANTS and DPX. Fusion of membranes was assessed by measuring the fluorescence of membrane-bound NBD-phosphatidylethanolamine (NBD-PE) and rhodamine-PE (RHO-PE). We found that SP-B bound to PL membranes with high affinity and appeared to irreversibly cluster at the membrane surface, leading to graded release of the vesicle contents and eventually fusion of the membranes with increasing protein-lipid ratios. All lipid mixtures tested were susceptible to the membrane disruptive effects of SP-B, but DPPC-eggPG membranes displayed a biphasic response to increasing molar fractions of eggPG, whereas increasing fractions of eggPC elicited a monotonic response.

Earlier identification of patients at risk from acetaminophen-induced acute liver failure

OBJECTIVE

To determine whether the Acute Physiology and Chronic Health Evaluation (APACHE) II system for the measurement of severity of illness is able to provide an accurate risk of hospital death in patients with acetaminophen-induced acute liver failure or identify those patients needing transfer for possible hepatic transplantation.

DESIGN

Data for admission (first 24 hrs) APACHE II scores and King's criteria for urgent transplantation were collected prospectively to compare the APACHE II system and the King's criteria for the prediction of death or need for transplantation.

SETTING

A nine-bed specialist liver failure unit (LFU).

PATIENTS

One hundred two consecutive patients admitted to the LFU with acetaminophen self-poisoning and a prolonged prothrombin time were studied.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

An APACHE II score of > 15 points was associated with a high mortality (13/20 patients, five of whom survived following hepatic transplantation). There was no relation between APACHE II risk and outcome (mean APACHE II risk of death 0.8%, actual hospital mortality 16%). An APACHE II score of > 15 had a similar power of prediction of death as the King's criteria (sensitivity 82% and 65%, respectively; specificity 98% and 99%, respectively), when considering those patients who were transplanted as "deaths." An APACHE II score of > 15 was able to identify four more patients than the King's criteria on the first day of admission to the LFU.

CONCLUSIONS

The crude admission APACHE II score correlated well with mortality in patients with acetaminophen-induced acute liver failure. However, the calculated APACHE II risk of death, using the original drug overdose coefficient, was poorly calibrated. Since specialist liver scores are unfamiliar in the general intensive care setting, the use of an APACHE II score might earlier identify more patients at risk of needing a liver transplant, and hence, expedite appropriate transfer to a specialist liver unit.

Transplantation of CG4 oligodendrocyte progenitor cells in the myelin-deficient rat brain results in myelination of axons and enhanced oligodendroglial markers

Transplantation of oligodendrocyte (Ol) progenitor cells into the central nervous system is a promising approach for the treatment of myelin disorders. This approach requires providing adequate numbers of healthy cells with myelinating potential. We recently showed the successful transplantation of Ol progenitors into the myelin-deficient (md) rat brain. In the present work, CG4 cells, a cell line with properties of Ol progenitors, were labeled with fast blue and grafted into P3-P5 pups born to carrier mothers. Examination of host brains 2 weeks posttransplant indicated that CG4 cells display a much more extensive migration capacity than their wild-type counterparts. These cells synthesized myelin components. In addition, ultrastructural analysis showed myelin formation along axons of md hosts in various brain regions, including corpus callosum, cerebellum, and brainstem. Furthermore, in situ hybridization studies performed on sagittal sections revealed extensive expression of transferrin-mRNA within the md host parenchyma. The high survival and functional features displayed by CG4 cells after transplantation, together with their striking wide distribution within the host parenchyma, as assessed by the presence of myelinated fibers in mutant hosts, emphasizes the importance of using highly motile and proliferative Ol progenitor cells. Strategies to improve the condition and life span of md rat pups are currently under investigation.

Gait analysis of adult paraplegic rats after spinal cord repair

This study presents a novel detailed method of analysis of rat gait and uses this method to demonstrate recovery of forward locomotion patterns in adult rats made paraplegic by surgical spinal cord transection and subjected to a novel strategy for spinal cord repair. Six normal rats were compared to five animals in which the cord was transected at T8-T9, and a 5-mm segment of the spinal cord removed, and to seven animals in which, following spinal cord transection and removal of a spinal cord segment, multiple intercostal peripheral nerve bridges were implanted, rerouting pathways from white to gray matter in both directions. The implanted area was filled with fibrin glue containing acidic fibroblast growth factor. Details of the repair strategy have been published (H. Cheng, Y. Cao, and L. Olson, 1996, Science 273: 510-513). Gait analysis was carried out 3 and 4 months after surgery and once in the normal animals. Animals were allowed to walk across a runway with a transparent floor. Each test consisted of five trials, and each trial was videorecorded from underneath. Using frame-by-frame playback, individual footprints were then recorded regarding location and order of limb use, as well as step quality (degree of weight bearing, etc.). These data allowed measuring runway transit time, five different measures of step numbers, all possible temporal patterns of limb use, stride length, and base of support. Transected controls remained paralyzed in the hindlimbs with only occasional reflex hindlimb movements without weight bearing. Animals subjected to the full repair procedure were significantly faster than the controls, used their hindlimbs for 25-30% of the movements, and regained several of the specific limb recruitment patterns used by normal rats. Taken together, the gait analysis data demonstrate remarkable recovery of coordinated gait in the repaired animals, which was significantly better than controls for all relevant parameters, while at the same time clearly inferior to normal rats for most of the examined parameters. We conclude that normal rats use a multitude of interchangeable step sequence patterns, and that our spinal cord repair strategy leads to recovery of some of these patterns following complete spinal cord transection. These data suggest functionally relevant neuronal communication across the lesion.

Nonsurgical therapy for pulmonary hydatid cyst disease

Therapeutic and diagnostic aspiration of Echinococcus granulosus liver cysts, but not pulmonary cysts, are increasingly being performed. Documented herein is the utility of percutaneous drainage and of albendazole treatment in a patient with a large recurrent, isolated, pulmonary echinococcal cyst for whom traditional therapy would have resulted in severe morbidity. Therapeutic options and possible complications are discussed.

Regulation of tPA in endothelial cells exposed to cyclic strain: role of CRE, AP-2, and SSRE binding sites

We have previously reported that exposure of cultured bovine aortic endothelial cells (EC) to 10% average strain resulted in an increase in tissue plasminogen activator (tPA) mRNA, immunoreactive tPA protein, and tPA activity in the medium. The present study was designed to examine the regulation of tPA gene expression in EC by cyclic strain. We performed a functional analysis of the tPA promoter by transfecting bovine aortic EC with a 1.4-kilobase (kb) construct of the human tPA promoter coupled to chloramphenicol acetyltransferase. We found that subjecting the EC to 10% average strain (and not 6% average strain) resulted in a 2.6-fold increase in activity of the 1.4-kb tPA promoter by 4 h. Analysis of deletion mutants of the promoter transfected into EC demonstrated a 60% drop-off in activity between position -145 and -105. Deoxyribonuclease I protection analysis of the segment downstream of position -196 suggested involvement of activator protein-2 (AP-2) and adenosine 3',5'-cyclic monophosphate-responsive element (CRE)-like binding sites, which was confirmed by electrophoretic mobility shift assays. Site-directed mutants of either the AP-2 or CRE-like regions resulted in a 65% decrease in activity compared with the wild type. Double mutations abolished basal transcription and any strain-induced activity. A shear stress responsive element (SSRE) binding site is present at -945, but site-directed mutants did not show any drop in activity compared with wild type by cyclic strain. These studies demonstrate that cyclic strain regulates tPA gene transcription in bovine aortic EC and that this transcriptional activation is dependent on factors that are similar to those activated with phorbol ester.

Identification of essential nucleotides of the FP1 element responsible for enhancement of low density lipoprotein receptor gene transcription

Low density lipoprotein (LDL) receptor gene is regulated at the transcriptional level by the intracellular level of sterols in animal cells. We have recently identified a 20 bp long region (-145 to -126), designated Footprint 1 (FP1), participating in maximal expression of the human LDL receptor gene in the absence of sterols in HepG2 cells [Mehta, K. D., Chang, R., Underwood, J., Wise, J. and Kumar, A. (1996) J. Biol. Chem ., 271, 33616-33622]. To determine the minimal FP1 sequence and to define the critical nucleotides required for function, a series of single nucleotide substitutions were introduced in the FP1 region. Twenty-three independent mutations were analyzed by transfection into HepG2 cells. These studies localize the regulatory region to 14 bp and demonstrate the requirement for essential guanine nucleotides at positions -135 and -136 for FP1 function. Furthermore, transfection studies suggest that the FP1-dependent increase in reporter gene expression is possibly mediated through interaction with the sterol-regulatory element. UV cross-linking and Southwestern blot analysis identified FP1-binding factors of approximately 50 and 125 kDa, which we have denoted p50 and p125. Mutations of the critical guanine residues (-135/-136) decreased the formation of the specific protein-DNA complex with the FP1 sequence and abolished its binding to the p125. We conclude that direct interaction of the p125 factor with these nucleotides of the FP1 element potentially contributes to FP1-dependent induction of LDL receptor gene expression.

The Kinmen Neurological Disorders Survey (KINDS): a study of a Chinese population

We conducted an epidemiological study of several neurological disorders among the Chinese aged 50 years or older on the islet of Kinmen. All participants were interviewed and examined by neurologists. From the targeted population of 5,061 individuals, 3,915 (77.4%) of them completed the evaluations. Among the 4,087 individuals with whom face-to-face contact was made, the refusal rate was 4.2%. The disorders of interest were dementia, Parkinson's disease, essential tremor, stroke, transient ischemic attacks, and migraine. Among the 3,915 participants, 366 cases were found with 1 or more of the surveyed neurological disorders on the prevalence day, August 1, 1993, yielding a prevalence of 93.5/1,000. The purpose of this study, the general methodology, and some overall findings are presented in this communication in order to provide a common background for detailed findings on each disorder to be reported separately.

Identification of a novel cis-acting element participating in maximal induction of the human low density lipoprotein receptor gene transcription in response to low cellular cholesterol levels

In this paper, we present both in vivo and in vitro evidence for the presence of a novel cis-acting regulatory element that is required for maximal induction of the human low density lipoprotein (LDL) receptor gene following depletion of cellular sterols in HepG2 cells. First, in vivo dimethyl sulfate footprinting of the human LDL receptor promoter before and after transcriptional induction in HepG2 cells revealed protection from -145 to -126, 5'-GAGCTTCACGGGTTAAAAAG-3' (referred to as FP1 site). Second, transient transfections of HepG2 cells with promoter luciferase reporter constructs containing the FP1 site resulted in significant enhancement (approximately 375%) of reporter gene expression in response to low levels of sterols compared with parallel plasmid without the FP1 site. In addition, this response was markedly attenuated on nucleotide substitutions within the FP1 site. Third, by electrophoretic mobility shift assays, the FP1 sequence was found to bind protein(s) from HepG2 nuclear extracts in a sequence-specific manner. In vitro binding of the FP1 mutants paralleled the results obtained for their in vivo transcription. On the basis of competition profiles, the FP1-binding factor is different from the known transcription factors binding to the AT-rich CArG and GArC motifs. Furthermore, the FP1-binding protein is not specific to HepG2 cells because nuclear factor(s) with the same specificity was observed in nuclear extracts of non-hepatic HeLa cells. We conclude that transcriptional induction of the LDL receptor gene in response to sterol depletion is mediated, in part, by an highly conserved novel cis-acting element through the binding of specific nuclear protein(s).

Hemodynamic effects of epinephrine, bicarbonate and calcium in the early postnatal period in a lamb model of single-ventricle physiology created in utero

OBJECTIVES

A reproducible fetal animal model of single-ventricle physiology was created to examine the effects of pharmacologic agents commonly used in the perinatal and perioperative intensive care management of patients with a single ventricle.

BACKGROUND

Single-ventricle physiology is characterized by parallel pulmonary and systemic circulations, with effective blood flow to each determined by the relative resistances in the pulmonary and systemic vascular beds. Perinatal and perioperative management of these patients is largely based on empiric observations and differs considerably between institutions and is further complicated by the transitional physiology of the newborn. The lack of animal models of single-ventricle physiology has hindered the understanding of this problem.

METHODS

A 10-mm, Damus-Kaye-Stansel-type aortopulmonary anastomosis was created in 10 fetal sheep at 140 +/- 1.2 days of gestation. The main pulmonary artery was ligated distally, and pulmonary blood flow (Qp) was provided through a 5-mm aortopulmonary shunt. Eight lambs were delivered at term and placed on cardiopulmonary bypass (30 min) 48 to 72 h after birth. Pharmacologic interventions (0.1 microgram/kg body weight per min of epinephrine, 2 mEq/kg of sodium bicarbonate and 10 mg/kg of calcium chloride) were performed before and after bypass, and hemodynamic responses were observed. The response to the epinephrine bolus was determined only in the postbypass study.

RESULTS

Both before and after bypass, epinephrine infusion and calcium and bicarbonate administration increased Qp and systemic blood flow (Qs) (total cardiac output) but produced only small changes in the Qp/Qs ratio (-0.5% to -7.3% change). With the epinephrine bolus, Qp increased enormously, and the Qp/Qs ratio increased by 584% (p < 0.001).

CONCLUSIONS

In neonatal lambs with single-ventricle physiology created in utero, epinephrine infusion and calcium and bicarbonate administration increased total cardiac output without significantly compromising the Qp/Qs ratio. However, epinephrine bolus seems to be hemodynamically detrimental in circumstances of single-ventricle physiology and should be used with caution and probably in relatively lower doses in the resuscitation of patients with single-ventricle physiology. Further investigation of the dose-dependent effects and the effects of prolonged administration of common pharmacologic agents will enable better management of patients with single-ventricle physiology.

Two-dimensional near-field intensity distribution of tapered fiber probes

The near-field intensity distribution perpendicular to the light-propagation direction was measured by photochemical processes on conjugated-polymer thin films. The shape of the distribution is elliptical, with the long axis along the direction of the incident polarization. The results are compared with calculations based on the realistic tapered probe geometry. The asymmetry distribution is due to the simultaneous presence of horizontal and vertical electric fields in the near field.

Pulse-spray treatment of subclavian and jugular venous thrombi with recombinant tissue plasminogen activator

PURPOSE

To evaluate the efficacy of recombinant tissue plasminogen activator (rtPA) injected by pulse-spray in lysing subclavian and jugular venous thrombi.

MATERIALS AND METHODS

Twelve patients with symptomatic, venogram-confirmed, occlusive thrombi of the subclavian-axillary or jugular veins were treated with one or two daily 15-minute injections of rtPA delivered directly into the clots with pulse-spray catheters. Twenty-four hours after each treatment, repeated venograms were obtained to assess venous patency. Successful thrombolysis was defined as antegrade flow through the previously occluded segments with minimal collateral venous flow. Continued patency was assessed with repeated venograms obtained after 1 and 2 months of oral anticoagulation.

RESULTS

The 15-minute rtPA injections successfully lysed thrombi in eight of the 12 patients. Hypofibrinogenemia developed in only one patient. The technique had a high success rate with thrombi less than 2 weeks old (seven of eight) regardless of the length of the clot, but had limited success with thrombi more than 2 weeks old (one of four). Continued patency over a 2-month interval was documented in four of the eight patients whose thrombi were successfully lysed. However, patency could be maintained in only one of the four patients who retained a venous access device in the treated vein.

CONCLUSION

Pulse spray rtPA is an effective, safe, and practical alternative to continuous infusions of thrombolytic agents to treat upper extremity venous thrombi.

Parathyroid adenomas in the aortopulmonary window

PURPOSE

To describe localization studies in nine patients with ectopic parathyroid adenomas in the aortopulmonary window.

MATERIALS AND METHODS

Nine patients with ectopic parathyroid tissue (eight adenomas, one hyperplastic gland) in the aortopulmonary window were examined with ultrasound (US), computed tomography (CT), magnetic resonance (MR) imaging, and scintigraphy. Diagnostic arteriography (n = 4) and venous sampling (n = 3) were performed in the first four patients; arteriography for the purpose of staining was attempted in the last five patients.

RESULTS

The results of CT and MR imaging studies were positive in eight of nine patients (89%) and five of eight patients (63%), respectively. The results of thallium/technetium scintigraphy were negative in three patients scanned (0%), but the results of a repeat study in one patient were positive (33%). Sestamibi scans were positive in six of six patients (100%). Single photon emission CT was performed in all six patients and enabled distinction between adenomas in the aortopulmonary window and those in the thymus.

CONCLUSION

Ectopic parathyroid glands in the aortopulmonary window are usually detected at sestamibi scintigraphy, and SPECT is helpful in distinguishing these adenomas from more common adenomas in the anterior mediastinum. CT and MR imaging studies can also enable this distinction, but imaging must extend below the aortic arch.

Functional properties of edible mushrooms

Edible mushrooms such as shiitake may have important salutary effects on health or even in treating disease. A mushroom characteristically contains many different bioactive compounds with diverse biological activity, and the content and bioactivity of these compounds depend on how the mushroom is prepared and consumed. It is estimated that approximately 50% of the annual 5 million metric tons of cultivated edible mushrooms contain functional "nutraceutical" or medicinal properties. In order of decreasing cultivated tonnage, Lentinus (shiitake), Pleurotus (oyster), Auricularia (mu-er), Flammulina (enokitake), Tremella (yin-er), Hericium, and Grifola (maitake) mushrooms have various degrees of immunomodulatory, lipid-lowering, antitumor, and other beneficial or therapeutic health effects without any significant toxicity. Although the data for this functional food class are not as strong as those for other functional foods such as cruciferous vegetables, because of their potential usefulness in preventing or treating serious health conditions such as cancer, acquired immune deficiency syndrome (AIDS), and hypercholesterolemia, functional mushrooms deserve further serious investigation. Additionally, there is a need for epidemiological evidence of the role of this functional food class.

Altered endothelium-dependent responses in lambs with pulmonary hypertension and increased pulmonary blood flow

To investigate early endothelial function associated with increased pulmonary blood flow, vascular shunts were placed between the ascending aorta and main pulmonary artery in 18 late-gestation fetal sheep. Four weeks after delivery, the lambs were instrumented to measure vascular pressures and blood flows, and blood was collected to measure plasma concentrations of guanosine 3',5'-cyclic monophosphate [cGMP, the second messenger to nitric oxide (NO)-mediated vasodilation] and L-arginine (the precursor for NO synthesis). The responses to the endothelium-dependent vasodilators acetylcholine (ACh, 1.0 microgram/kg) and ATP (0.1 mg.kg-1.min-1), the endothelium-independent vasodilators M & B-22948 (a cGMP-specific phosphodiesterase inhibitor, 2.5 mg/kg) and inhaled NO (40 ppm), and N omega-nitro-L-arginine (an inhibitor of NO synthase, 5 mg/kg) were then compared with responses in 12 age-matched controls. Vasodilator responses in control lambs were determined during pulmonary hypertension induced by U-46619 (a thromboxane A2 mimic). Shunted lambs displayed a selective impairment of endothelium-dependent pulmonary vasodilation, an augmented pulmonary vasoconstricting response to NO synthase inhibition, increased plasma cGMP concentrations, and decreased L-arginine concentrations. Taken together, these data suggest that lambs with pulmonary hypertension and increased pulmonary blood flow have early aberrations in endothelial function, as manifested by increased basal NO activity, that cannot be further increased by agonist-induced endothelium-dependent vasodilators.

Small peptides as potent mimetics of the protein hormone erythropoietin

Random phage display peptide libraries and affinity selective methods were used to isolate small peptides that bind to and activate the receptor for the cytokine erythropoietin (EPO). In a panel of in vitro biological assays, the peptides act as full agonists and they can also stimulate erythropoiesis in mice. These agonists are represented by a 14- amino acid disulfide-bonded, cyclic peptide with the minimum consensus sequence YXCXXGPXTWXCXP, where X represents positions allowing occupation by several amino acids. The amino acid sequences of these peptides are not found in the primary sequence of EPO. The signaling pathways activated by these peptides appear to be identical to those induced by the natural ligand. This discovery may form the basis for the design of small molecule mimetics of EPO.

Prediction of outcome in critically ill patients using artificial neural network synthesised by genetic algorithm

BACKGROUND

Decisions about which patients to admit to intensive care and how long to keep them there are difficult. A flexible computer-based mathematical model which is sensitive to the complexity of intensive care medicine, and which accurately models prognosis, seems highly desirable.

METHODS

We have created, optimised by genetic algorithms, trained, and evaluated the performance of an artificial neural network (ANN) in the clinical setting of systemic inflammatory response syndrome and haemodynamic shock. 258 patients were selected from an intensive care database of 4484 patients at a London teaching hospital and randomised to a network training set (168) and a test set (90). The outcome evaluated was death during that hospital admission and the performance of the neural net was compared (by receiver operating characteristic [ROC] curves and by Brier scores) with that of a logistic regression model.

FINDINGS

Artificial neural network performance increased with successive generations; the best-performing ANN was created after 7 generations and predicted outcome more accurately than the logistic regression model (ROC curve area 0.863 vs 0.753).

INTERPRETATION

In this study, ANNs have lent themselves particularly well to modelling a complex clinical situation; we suggest that this relates to their inherently flexible nature which accommodates interactions between the clinical input fields. In addition, we have demonstrated the value of a second computational technique (genetic algorithms) in "tuning" ANN performance. These techniques can potentially be implemented in individual intensive care units; the outcome models which they will generate will be sensitive to local practice. Analysis of such accurate clinical outcome models may empower clinicians with a hitherto unappreciated degree of insight into those elements of their clinical practice which are most relevant to their patients' outcome.

Phase I crossover study of paclitaxel with r-verapamil in patients with metastatic breast cancer

PURPOSE

We conducted a phase I crossover study of escalating doses of both paclitaxel (Taxol; Bristol-Myers, Squibb, Princeton, NJ) and r-verapamil, the less cardiotoxic stereoisomer, in heavily pretreated patients with metastatic breast cancer.

PATIENTS AND METHODS

Twenty-nine patients refractory to paclitaxel by 3-hour infusion were treated orally with r-verapamil every 4 hours starting 24 hours before the same-dose 3-hour paclitaxel infusion and continuing for a total of 12 doses. Once the maximum-tolerated dose (MTD) of the combination was determined, seven additional patients who had not been treated with either drug were evaluated to determine whether the addition of r-verapamil altered the pharmacokinetics of paclitaxel. Consenting patients had tumor biopsies for P-glycoprotein (Pgp) expression before receiving paclitaxel and after becoming refractory to paclitaxel therapy.

RESULTS

The MTD of the combination was 225 mg/m2 of r-verapamil every 4 hours with paclitaxel 200 mg/m2 by 3-hour infusion. Dose-limiting hypotension and bradycardia were observed in three of five patients treated at 250 mg/m2 r-verapamil. Fourteen patients received 32 cycles of r-verapamil at the MTD as outpatient therapy without developing cardiac toxicity. The median peak and trough serum verapamil concentrations at the MTD were 5.1 micromol/L (range, 1.9 to 6.3), respectively, which are within the range necessary for in vitro modulation of Pgp-mediated multidrug resistance (MDR). Increased serum verapamil concentrations and cardiac toxicity were observed more frequently in patients with elevated hepatic transaminases and bilirubin levels. Hematologic toxicity from combined paclitaxel and r-verapamil was significantly worse compared with the previous cycle of paclitxel without r-verapamil. In the pharmacokinetic analysis, r-verapamil delayed mean paclitaxel clearance and increased mean peak paclitaxel concentrations.

CONCLUSION

r-Verapamil at 225 mg/m2 orally every 4 hours can be given safely with paclitaxel 200 mg/m2 by 3-hour infusion as outpatient therapy and is associated with serum levels considered active for Pgp inhibition. The addition of r-verapamil significantly alters the toxicity and pharmacokinetics of paclitaxel.

Chiloscyllium plagiosum low-density lipoprotein receptor: evolutionary conservation of five different functional domains

All five functional domains of the low-density lipoprotein (LDL) receptor were assembled in their modern form more than 450 million years ago, as revealed from the cloning and sequencing of an LDL receptor cDNA from Chiloscyllium plagiosum (banded cat shark). The shark LDL receptor has the same overall architecture as the mammalian and amphibian counterparts. Each of the seven cysteine-rich repeats in the ligand binding domain resembles its counterpart in the human LDL receptor more than it does the other repeats in the shark receptor as suggested by the presence of unique "signature" sequences, indicating that these repeats had already acquired their independent structures by the time of shark development. Furthermore, amino acid sequences of the entire ligand binding domain of shark LDL receptor show 35% identity over a stretch of 294 residues with a Lymnaea stagnalis G-protein-linked receptor (LSGLR). The region of homology between these unrelated proteins includes conservation of most of the unique characteristics of the cysteine-rich repeats of LDL receptor at the expected positions in LSGLR. The results presented are consistent with the hypothesis that all seven repeats in the ligand binding domain of LDL receptor may have been lifted directly from an ancestral gene instead of being evolutionary duplications of a single repeat recruited by the primitive LDL receptor from another gene.

Role of tissue diagnosis in pulmonary involvement in pediatric human immunodeficiency virus infection

BACKGROUND

Pulmonary complications occur commonly during HIV infection. The aim of this study was to evaluate the clinical value of lung tissue examination in the diagnosis and treatment of pulmonary disorders in children with HIV infection.

METHODS

The medical records of 347 children enrolled between January, 1990, and April, 1994, into various antiretroviral therapy protocols were reviewed to identify patients who underwent a lung biopsy.

RESULTS

Fourteen patients underwent diagnostic lung biopsies on 16 separate occasions. The most common radiologic findings were nodular infiltrates which were localized in 7 patients and diffuse in 6. Eight patients presented with fever and progressive respiratory distress unresponsive to empiric therapy, whereas the rest had progressive nodular infiltrates. The pathologic diagnoses included opportunistic infection in 7 patients, lymphocytic interstitial pneumonitis in 5, non-Hodgkin's lymphoma in 3 and interstitial fibrosis in 1. The biopsy led to a major change in the treatment of 7 patients which resulted in a significant improvement of the pulmonary process in all of them. In an additional patient the excisional biopsy proved curative.

CONCLUSIONS

When patients are selected appropriately, lung biopsy might have a significant impact on therapy and outcome in HIV-infected children with pulmonary infiltrates.

In vivo role of the Sp1 site neighboring sterol-responsive element-1 in controlling low-density lipoprotein receptor gene expression

The in vivo role of the crucial Sp1 site neighboring sterol-responsive element-1 (SRE-1) in controlling LDL receptor gene expression in the presence or absence of sterols was examined. For this purpose the Xenopus laevis system was utilized as there are two different genes for LDL receptors in frogs which differ in their promoter region in the Sp1-binding sequence of repeat 3 present immediately adjacent to SRE-1. DNase I footprinting of promoters of both receptors showed differences in the affinity of this Sp1 site to purified transcription factor Sp1. Transcript levels of both LDL receptors were measured in livers of frogs on normal and cholesterol-enriched diets. Basal levels and extent of repression of LDL receptor gene on sterol administration were found to be dependent on the nature of the Sp1 site of repeat 3 under in vivo conditions. We conclude that this Sp1 site acts as a constitutive positive transcriptional element that forms a part of the active transcription complex irrespective of cellular sterol levels.

Metastatic gastrinomas: localization with selective arterial injection of secretin

PURPOSE

To evaluate localization of hepatic metastases with the intraarterial secretin injection test in Zollinger-Ellison syndrome (ZES).

MATERIALS AND METHODS

Results in 74 patients with ZES (aged 15-70 years) were retrospectively studied. All patients had undergone computed tomography (CT), magnetic resonance (MR) imaging, ultrasound, abdominal angiography, and an intraarterial secretin test, in which venous blood is sampled periodically after injection of secretin.

RESULTS

Twenty-two patients had liver metastases. An increase in venous gastrin concentration of at least 25% at 20 seconds or 50% at 30 seconds after injection indicated a positive result. Results were positive in 41% of patients with and 2% without liver metastases (P < .0001). Sensitivity of the intraarterial secretin test was 41%; of CT and ultrasound, 64%; and of MR imaging and angiography, 77%. Intraarterial secretin test results assisted in clinical management in 22% of patients.

CONCLUSION

With the criteria developed, the intraarterial secretin test had high specificity but low sensitivity. It should be used when imaging results are unclear.

Novel form of actin-based motility transports bacteria on the surfaces of infected cells

Enteropathogenic Escherichia coli (EPEC) attach to cells (attachment) lining the intestine and induce a decrease in the number of the cells' microvilli (effacement). This attachment and effacement is followed by diarrhea, which may be explained, at least in part, to the loss of microvilli and the decreased ability of the infected cells to absorb fluids. EPEC also attach to the surfaces of a number of cultured cells including CaCo-2, LLC-PK, and PtK2 cells. The extracellular, attached EPEC induce filaments of actin to form in the cytoplasm just underneath the EPEC surface attachment sites. Beneath some of the attached EPEC, the actin filaments become organized into membrane encased columns that extend up to 6 micrometers above the cell surface creating "pedestals" on which the EPEC rest. The raised pedestals can be readily observed in stereo pairs taken using the Intermediate Voltage Electron Microscope. The concentration of non-muscle isoforms of myosin II and tropomyosin near the base of the pedestals suggests a similarity of these structures to brush border microvilli. Video microscopy indicates that these EPEC pedestals can bend and undulate, alternately growing longer and shorter while remaining tethered in place on the cell surface. Some of the attached EPEC also translocate along the cell surface, reaching speeds up to 0.07 micrometers/sec. Both types of movement are inhibited by cytochalasin D, indicating that actin polymerization in the pedestals is required for the motility of EPEC on the host cell surface. In this respect, EPEC motility on host cells resembles the intracellular motility of Listeria, but there are differences in the actin filament bundles induced by the two different bacteria. The most obvious one is the interposition of the cell membrane between EPEC and the actin filaments in the pedestal in contrast to the close apposition of actin filaments to Listeria. The intensity of fluorescence of rhodamine phalloidin is nearly uniform along most of the length of the pedestals indicating a constant number of actin filaments, whereas the fluorescence intensity decreases along the length of Listeria tails reflecting the disassembly that occurs all along the tails. Epec's movements may be a hybrid of Listeria filopodia and Aplysia inductopodia movements. This paper is the first report of a microbe attached to the extracellular surface of an infected cell propelled by an intracellular actin polymerization-dependent mechanism.

Novel form of actin-based motility transports bacteria on the surfaces of infected cells

Enteropathogenic Escherichia coli (EPEC) attach to cells (attachment) lining the intestine and induce a decrease in the number of the cells' microvilli (effacement). This attachment and effacement is followed by diarrhea, which may be explained, at least in part, to the loss of microvilli and the decreased ability of the infected cells to absorb fluids. EPEC also attach to the surfaces of a number of cultured cells including CaCo-2, LLC-PK, and PtK2 cells. The extracellular, attached EPEC induce filaments of actin to form in the cytoplasm just underneath the EPEC surface attachment sites. Beneath some of the attached EPEC, the actin filaments become organized into membrane encased columns that extend up to 6 micrometers above the cell surface creating "pedestals" on which the EPEC rest. The raised pedestals can be readily observed in stereo pairs taken using the Intermediate Voltage Electron Microscope. The concentration of non-muscle isoforms of myosin II and tropomyosin near the base of the pedestals suggests a similarity of these structures to brush border microvilli. Video microscopy indicates that these EPEC pedestals can bend and undulate, alternately growing longer and shorter while remaining tethered in place on the cell surface. Some of the attached EPEC also translocate along the cell surface, reaching speeds up to 0.07 micrometers/sec. Both types of movement are inhibited by cytochalasin D, indicating that actin polymerization in the pedestals is required for the motility of EPEC on the host cell surface. In this respect, EPEC motility on host cells resembles the intracellular motility of Listeria, but there are differences in the actin filament bundles induced by the two different bacteria. The most obvious one is the interposition of the cell membrane between EPEC and the actin filaments in the pedestal in contrast to the close apposition of actin filaments to Listeria. The intensity of fluorescence of rhodamine phalloidin is nearly uniform along most of the length of the pedestals indicating a constant number of actin filaments, whereas the fluorescence intensity decreases along the length of Listeria tails reflecting the disassembly that occurs all along the tails. Epec's movements may be a hybrid of Listeria filopodia and Aplysia inductopodia movements. This paper is the first report of a microbe attached to the extracellular surface of an infected cell propelled by an intracellular actin polymerization-dependent mechanism.

Impact of recounting trauma stories on the emotional state of Cambodian refugees

Twenty Cambodian refugees with premigration histories of trauma received an average of 16 sessions of individual therapy from a Cambodian bicultural counselor at a trauma treatment center in Sydney, Australia. Nineteen of the 20 patients reported that during treatment they had been willing to talk about their trauma histories, a finding that raises doubts about the commonly held belief that Asians are not psychologically minded and avoid disclosing emotionally sensitive information to health care workers. However, self-disclosing therapy alone did not appear to benefit these patients. Only four patients found talking about their trauma story directly helpful in improving their emotional state, and three of the four found the relief to be transitory.

Effects of carbohydrate type and concentration and solution osmolality on water absorption

We studied intestinal absorption of solutions containing either one (glucose, Glu, or maltodextrin, Mal) or two (fructose, Fru, and Glu or sucrose, Suc) transportable carbohydrate (CHO) substrates using segmental perfusion technique in eight healthy male subjects. These CHO were either free or directly transportable monosaccharides (Glu, Fru), bound as the disaccharide (sucrose, Suc), or as oligomers (maltodextrins, Mal). [CHO] was varied from 6% to 8% (120-444 mmol.1(-1)). All solutions contained low [Na+] (15-19 mEq) and [K+] (3-4 mEq). Solutions osmolalities varied from 165 to 477 mOsm.kg(-1). Osmolalities in the test segment ranged from 268 to 314 mOsm.kg(-1). The regression line of osmolality with water absorption differed for single as compared with multiple substrate solutions. The significantly different intercepts of these two regression lines suggest that solutions with multiple substrates produce greater water absorption at a given osmolality than those with one. Comparing all solutions, test segment solute flux (partial r = 0.69) was more important than mean osmolality (partial r = 0.32). In conclusion, solutions with multiple substrates stimulate several different solute absorption mechanisms yielding greater water absorption than solutions with only one substrate.

In vitro cytokine profiles and their relevance to rejection following renal transplantation

Graft rejection remains an important cause of renal allograft failure, despite improvements in immunosuppression and HLA typing. Although HLA matching is beneficial, ensuring an exact match it is often impractical. Thus, a reliable in vitro method for quantitating and qualitating alloreactivity is an important goal. In this study, we measured in vitro the cytokine secretion profiles of mononuclear cells from patients prior to renal transplantation by stimulating with anti-CD3 monoclonal antibody and suppressing with cyclosporine. Mononuclear cells from patients who subsequently developed acute cellular rejection secreted higher mean levels of interleukin (IL)-2 and gamma-interferon (IFN-gamma) than those from patients who had no rejection episodes. IFN-gamma secretion was significantly associated with rejection (P = 0.002), whereas IL-2 secretion did not quite reach statistical significance. There was no significant correlation between IL-4 levels and rejection. Although cyclosporine suppressed the secretion of both IL-2 and IFN-gamma, there was no difference in sensitivity to suppression between rejectors and nonrejectors. These results further emphasize the importance of the TH1 lymphocyte subset in renal allograft rejection. The IFN-gamma secretory capacity of alloreactive T cells may influence the outcome of a renal allograft by (1) activating graft infiltrating macrophages and/or (2) up-regulating HLA molecules on the graft.

Localization of insulinomas to regions of the pancreas by intra-arterial stimulation with calcium

OBJECTIVE

To determine the sensitivity of calcium injected into pancreatic arteries in localizing insulin-secreting tumors to regions of the pancreas.

DESIGN AND PATIENTS

To stimulate the release of insulin, 25 patients with surgically proven insulinomas (average diameter, 15 mm) had calcium gluconate (0.025 mEq Ca++/kg body weight) injected before surgery into the arteries supplying the pancreatic head (gastroduodenal and superior mesenteric arteries) and the body and tail (splenic artery) of the pancreas.

SETTING

Tertiary referral hospital.

MEASUREMENTS

Insulin levels were measured in samples taken from the right and left hepatic veins before and 30, 60, and 120 seconds after calcium injection. A twofold increase in insulin level in the sample taken from the right hepatic vein 30 or 60 seconds after injection localized the insulinoma to the segment of the pancreas supplied by the selectively injected artery. Localization done using calcium stimulation was compared with localization done using transcutaneous ultrasonography (n = 22), computed tomography (n = 23), magnetic resonance imaging (n = 21), arteriography (n = 25), and portal venous sampling (n = 9).

RESULTS

Calcium stimulation localized 22 of 25 insulinomas (sensitivity, 88% [95% CI, 68% to 97%]) to the correct region of the pancreas. The sensitivities of the other imaging methods were 9% for ultrasonography (CI, 1% to 23%), 17% for computed tomography (CI, 5% to 39%), 43% for magnetic resonance imaging (CI, 22% to 66%), 36% for arteriography (CI, 18% to 57%), and 67% for portal venous sampling (CI, 30% to 93%). Calcium stimulation added only a few minutes to the time needed for pancreatic arteriography and caused no morbid conditions.

CONCLUSION

Intra-arterial calcium stimulation with right hepatic vein sampling for insulin gradients is the most sensitive preoperative test for localizing insulinomas.

Selective venous sampling from the cavernous sinuses is not a more reliable technique than sampling from the inferior petrosal sinuses in Cushing's syndrome

The purpose of this study was to compare ACTH levels in unstimulated samples obtained from the cavernous sinuses (CS) to unstimulated and CRH-stimulated samples obtained from the inferior petrosal sinuses (IPS) in 15 patients with surgically proven Cushing's disease. After unstimulated samples were obtained through 5-French catheters placed in both IPS, tracker catheters were introduced into both cavernous sinuses, and unstimulated samples were obtained within 5 min of the initial set. The Tracker catheters were removed, CRH was administered, and CRH-stimulated samples were obtained from the IPS. We compared the central to peripheral ACTH ratios in unstimulated samples from the cavernous sinuses to unstimulated and CRH-stimulated samples from the IPS as a basis for distinguishing pituitary from ectopic ACTH production. In addition, we compared the ability of the intercavernous and interpetrosal ACTH ratios to correctly predict the site of the microadenoma. Unstimulated levels of ACTH in the cavernous sinuses were generally higher than unstimulated levels of ACTH in the petrosal sinuses. However, 3 of 15 patients failed to show central to peripheral ACTH ratios greater than 2 in unstimulated samples from the cavernous sinuses and were thus falsely negative for the diagnosis of Cushing's disease (test sensitivity, 80%). By comparison, the test sensitivity for the petrosal sinus samples was 87% for the unstimulated samples and 100% for the CRH-stimulated samples. Lateralization was correct in 6 of 15 patients based on CS samples and in 9 of 15 patients based on IPS samples. Because of the 20% false negative rate, CS sampling without CRH stimulation is not recommended for the differential diagnosis of ACTH-dependent hypercortisolism.

Affinity purification of human plasma vitamin D-binding protein

During the course of our studies to probe the vitamin D ligand-binding domains of vitamin D-binding protein and vitamin D receptor, we developed a synthetic procedure to modify the 3 beta-hydroxyl group of vitamin D3 and its 25-hydroxy- and 1,25-dihydroxy metabolites with a 3'-aminopropylether group. In the present study we have coupled 25-hydroxyvitamin D3-3 beta-3'-aminopropylether to an activated Sepharose matrix. Using this stable and reusable affinity matrix we have purified human vitamin D-binding protein from human plasma to homogeneity.

Prevention of duodenal ulcer relapse with omeprazole 20 mg daily: a randomized double-blind, placebo-controlled study

We report the first double-blind, placebo-controlled study that assesses the efficacy and safety of omeprazole 20 mg daily in the maintenance treatment of duodenal ulcer. For the healing phase, 128 patients with endoscopically proven active duodenal ulcer and a history of three or more relapses during the 2 years prior to the study were treated until healing with omeprazole 40 mg daily for 2 and up to 8 weeks. One hundred and twenty-three patients whose ulcers were healed were randomized to receive omeprazole 20 mg daily (n = 60) or placebo (n = 63) for 12 months as maintenance treatment. Patients were interviewed at 3, 6, 9 and 12 months, and endoscopy was performed at 3, 6 and 12 months and whenever symptoms recurred. The healing rates of the 124 patients completing the healing phase were 84, 98 and 100% at 2, 4 and 8 weeks, respectively. During the maintenance phase, eight and four patients discontinued treatment from the omeprazole and placebo groups, respectively. The proportion of patients in remission in the omeprazole group and placebo group after 12 months were 94 and 9% respectively (life table estimates, P < 0.0001). No significant clinical or laboratory changes were observed in patients on therapy with omeprazole. Patients with a history of frequent relapses thus continued to have a very high relapse rate without prophylactic treatment. Omeprazole 20 mg daily was effective and safe in maintaining such patients in remission.

Interleukin-6 prevents dexamethasone-induced myeloma cell death

The effects of dexamethasone on the growth of four human multiple myeloma cell lines were studied. In addition, the effects on the expression of interleukin-6 (IL-6) and IL-6 receptor (IL-6R) genes were investigated by the use of reverse-transcriptase polymerase chain reaction. Dexamethasone (Dex) concentrations of 10(-7) to 10(-6) mol/L inhibited IL-6 gene expression in three of four cell lines studied, whereas the higher concentration of the hormone inhibited also IL-6R gene expression. Dex effects were modulated through the glucocorticoid receptor (GR). Dex treatment resulted in killing of sensitive cells associated with DNA fragmentation, which could be reversed by concomitant treatment with IL-6. The reversal of Dex-mediated effects by IL-6 did not result from an inhibition of GR function as measured by receptor nuclear translocation or Dex-regulated reporter gene function. These results indicate that blockage of the IL-6 signaling pathway is essential for effective myeloma cell kill by Dex.

Inefficient processing of human protein C in the mouse mammary gland

Vitamin K-dependent plasma protein, human Protein C (HPC) has been expressed in transgenic mice, using a 4.2 kb mouse whey acidic protein (WAP) promoter, 9.0 kb HPC gene and 0.4 kb 3' flanking sequences. Expression was mammary gland-specific and the recombinant human Protein C (rHPC) was detected in milk at concentrations of 0.1 to 0.7 mg ml-1. SDS-PAGE revealed that the single, heavy and light chains of rHPC migrated with increased electrophoretic mobility, as compared to HPC. Enzymatic deglycosylation showed that these molecular weight disparities are in part due to differential glycosylation. The substantial increase observed in the amount of single chain protein, as well as the presence of the propeptide attached to 20-30% of rHPC, suggest that mouse mammary epithelial cells are not capable of efficient proteolytic processing of rHPC. The Km of purified rHPC for the S-2366 synthetic substrate was similar to that of plasma-derived HPC, while the specific activity was about 42-77%. Amino acid sequence analyses and low anticoagulant activity of purified rHPC suggest that gamma-carboxylation of rHPC is insufficient. These results show that proteolytic processing and gamma-carboxylation can be limiting events in the overexpression of fully biologically active rHPC in the mouse mammary gland.

Treatment with intralesional granulocyte instillations and interferon-gamma for a patient with chronic granulomatous disease and multiple hepatic abscesses

We present the case of a 16-year-old girl with p22-deficient chronic granulomatous disease in whom multiple hepatic abscesses secondary to Staphylococcus aureus infection developed. Infection persisted despite extensive surgery and aggressive antibiotic therapy. Conventional intravenous granulocyte transfusions were not tolerated because of the development of alloantibodies to HLA. Treatment with interferon-gamma and intralesional granulocyte infusions was associated with dramatic clinical and radiographic improvement. No morbidity was associated with this therapy. To our knowledge, this is the first report of treatment with intralesional granulocyte instillations. Intralesional granulocyte instillation in association with interferon-gamma administration may result in clinical improvement in the conditions of patients with chronic granulomatous disease and hepatic abscesses for whom conventional therapy has failed.

Dilation of lower ureteral strictures with Van Andel catheters

We present a simple method to dilate ureteral strictures, which was performed in 7 patients with metastatic cancer (1 breast, 1 lymphoma, 2 ovarian and 3 colorectal tumors) who presented with newly discovered obstruction in the distal ureter. The obstruction was due to tumor in the pelvis in 5 patients and to pelvic radiotherapy in 2. A 0.035-inch guide wire was passed beyond the stricture cystoscopically. In each case a double pigtail stent could not be passed beyond the stricture over the guide wire. The strictures were then dilated with progressively larger Van Andel catheters passed over the guide wire through the cystoscope. Following dilation a 7.5F to 8.5F soft double pigtail catheter was easily advanced. All patients had good drainage on followup radiographic studies. The method is presented as an alternative to balloon dilation of lower ureteral strictures when the goal is placement of an adequate diameter indwelling ureteral stent.

Evaluation of the efficacy of prolonged administration of azithromycin in a murine model of chronic toxoplasmosis

The efficacy of prolonged administration of azithromycin was evaluated in a murine model of lethal chronic toxoplasmosis. Mice were challenged intraperitoneally with cysts of a moderately virulent strain of Toxoplasma gondii, observed for 4 weeks and then allocated to the treatment or control group. All 26 animals given azithromycin 100 mg/kg/day for 100 days were protected compared with 19 of 25 control animals which died (P < 0.001). Nineteen of the 20 mice in the treatment group survived for an additional month while receiving the same azithromycin regimen but viable cysts were identified in the brain tissue of these animals when they were killed. Although there was no significant difference between the groups in terms of the number of cysts in the brain, the administration of azithromycin was associated with a reduction in brain inflammation. The concentrations of azithromycin in the brains of five animals ranged from 0.7 to 2.3 micrograms/g; there was no evidence of accumulation even after 100 doses. Azithromycin merits further evaluation as primary or secondary prophylaxis against toxoplasma encephalitis in individuals at risk of developing this complication.

Role of polymorphonuclear neutrophil leukocytes and their integrin CD11a (LFA-1) in the pathogenesis of severe murine malaria

Infection of CBA mice with Plasmodium berghei ANKA results in severe malaria, which is characterized by mortality 6 to 10 days after infection and is associated with alterations of the brain microcirculation. These alterations consist of (i) intravascular sequestration of monocytes, (ii) an increase in vascular permeability as documented by Evans blue diffusion, and (iii) microhemorrhages. This syndrome may be due to an increase of production of tumor necrosis factor alpha which upregulates the endothelial expression of ICAM-1 and thus leads to adhesion of CD11a/CD18 (LFA-1)-bearing cells. During severe malaria, we found an important sequestration of the CD11a-bearing polymorphonuclear neutrophil leukocytes (PMN) in the lung but not in the brain. Treatment with a monoclonal antibody (MAb) against PMN, which induces profound neutropenia, prevented mortality and Evans blue diffusion in the brain and the lung, while it unexpectedly increased the occurrence of microhemorrhages. The anti-PMN MAb abolished PMN sequestration in the lung and also partially decreased monocyte sequestration in the brain and the lung. Treatment with an anti-CD11a MAb also prevented mortality, Evans blue diffusion, and PMN and monocyte sequestration. This study shows that PMN contribute to the mortality and the microvascular lesions resulting from severe malaria. This may be due to their CD11a-dependent sequestration in the lung and also to their indirect influence on vascular permeability and the sequestration of monocytes.

Neurologic diseases presenting with gait impairment in the elderly

We conducted a prospective study to evaluate the underlying diseases and their frequencies in 50 consecutive patients older than 50 years of age admitted to our neurologic service because of walking difficulty. The diseases identified in our study were as follows: multiple cerebral infarcts, 24%; myelopathy, 22%; parkinsonism, 12%; cerebellar degeneration, 8%; other diseases, 24%; and unknown etiology, 10%. Potentially treatable causes of gait impairment were found in nearly one third of patients.

A double-blind, randomized, parallel group study of omeprazole and ranitidine in Korean patients with gastric ulcer

The efficacy of the proton pump inhibitor omeprazole, 20 mg every morning, was compared with that of the H2-receptor antagonist ranitidine, 150 mg every morning and at bedtime, in a double-blind randomized parallel group study in 250 patients with gastric or prepyloric ulcers. At both 4 and 8 weeks, significantly more patients had healed ulcers in the omeprazole group than the ranitidine group, whether the results were analysed on a per-protocol or an intention-to-treat basis. At 4 weeks, 74% of patients in the omeprazole group were healed compared with 51% in the ranitidine group (P = 0.001), and at 8 weeks the corresponding values were 99 and 82% (P = 0.001, per-protocol cohort). Omeprazole treatment and small ulcer size significantly increased the probability of healing, but smoking had no significant effect. Patients in the omeprazole group had significantly fewer occurrences of daytime epigastric pain during the first 4 weeks than the ranitidine group (P = 0.0037), as shown by their diary cards. Both treatments were well tolerated.