Safety, pharmacokinetics and target engagement of novel RIPK1 inhibitor SAR443060 (DNL747) for neurodegenerative disorders: Randomized, placebo-controlled, double-blind phase I/Ib studies in healthy subjects and patients

RIPK1 is a master regulator of inflammatory signaling and cell death and increased RIPK1 activity is observed in human diseases, including Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS). RIPK1 inhibition has been shown to protect against cell death in a range of preclinical cellular and animal models of diseases. SAR443060 (previously DNL747) is a selective, orally bioavailable, central nervous system (CNS)–penetrant, small‐molecule, reversible inhibitor of RIPK1. In three early‐stage clinical trials in healthy subjects and patients with AD or ALS (NCT03757325 and NCT03757351), SAR443060 distributed into the cerebrospinal fluid (CSF) after oral administration and demonstrated robust peripheral target engagement as measured by a reduction in phosphorylation of RIPK1 at serine 166 (pRIPK1) in human peripheral blood mononuclear cells compared to baseline. RIPK1 inhibition was generally safe and well‐tolerated in healthy volunteers and patients with AD or ALS. Taken together, the distribution into the CSF after oral administration, the peripheral proof‐of‐mechanism, and the safety profile of RIPK1 inhibition to date, suggest that therapeutic modulation of RIPK1 in the CNS is possible, conferring potential therapeutic promise for AD and ALS, as well as other neurodegenerative conditions. However, SAR443060 development was discontinued due to long‐term nonclinical toxicology findings, although these nonclinical toxicology signals were not observed in the short duration dosing in any of the three early‐stage clinical trials. The dose‐limiting toxicities observed for SAR443060 preclinically have not been reported for other RIPK1‐inhibitors, suggesting that these toxicities are compound‐specific (related to SAR443060) rather than RIPK1 pathway‐specific.

DNL104, a Centrally Penetrant RIPK1 Inhibitor, Inhibits RIP1 Kinase Phosphorylation in a Randomized Phase I Ascending Dose Study in Healthy Volunteers

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) regulates inflammation, cytokine release, and necroptotic cell death and is implicated in pathogenic cellular pathways in amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and multiple sclerosis. Inhibition of RIPK1 activity protects against inflammation and cell death in multiple animal models. DNL104 is a selective, brain-penetrant inhibitor of RIPK1 phosphorylation in clinical development for AD and ALS. DNL104 was tested in 68 healthy volunteers to investigate safety and tolerability, pharmacokinetic profile in plasma and cerebrospinal fluid, and pharmacodynamic effects of RIPK1 inhibition in peripheral blood mononuclear cells in a first-in-human, placebo-controlled, double-blind, randomized single-ascending dose (SAD) and multiple-ascending dose (MAD) study. DNL104 was well-tolerated in the SAD group and during the dosing period of the MAD group. However, postdose liver toxicity in 37.5% of subjects was observed in the MAD, and assessed to be drug related. We demonstrate that DNL104 leads to RIP1 kinase inhibition, and this is not associated with central nervous system (CNS) toxicities, supporting future development of CNS penetrant RIPK1 inhibitors.

Review article: nonclinical and clinical pharmacology, pharmacokinetics and pharmacodynamics of etrolizumab, an anti-β7 integrin therapy for inflammatory bowel disease

BACKGROUND

Novel treatments with superior benefit-risk profiles are needed to improve the long-term prognosis of patients with inflammatory bowel disease (IBD). Etrolizumab-a monoclonal antibody that specifically targets β7 integrins-is currently under phase III clinical evaluation in IBD.

AIM

This review summarises the available pharmacological and pharmacokinetic/pharmacodynamic data for etrolizumab to provide a comprehensive understanding of its mechanism of action (MOA) and pharmacological effects.

METHODS

Published and internal unpublished data from nonclinical and clinical studies with etrolizumab are reviewed.

RESULTS

Etrolizumab exerts its effect via a unique dual MOA that inhibits both leucocyte trafficking to the intestinal mucosa and retention within the intestinal epithelial layer. The gut-selectivity of etrolizumab results from its specific targeting of the β7 subunit of α4β7 and αEβ7 integrins. Etrolizumab does not bind to α4β1 integrin, which mediates lymphocyte trafficking to tissues including the central nervous system, a characteristic underlying its favourable safety with regard to progressive multifocal leucoencephalopathy. Phase I/II studies in patients with ulcerative colitis (UC) showed linear pharmacokinetics when etrolizumab was administered subcutaneously at 100 mg or higher once every 4 weeks. This dose was sufficient to enable full β7 receptor occupancy in both blood and intestinal tissues of patients with moderate to severe UC. The phase II study results also suggested that patients with elevated intestinal expression of αE integrin may have an increased likelihood of clinical remission in response to etrolizumab treatment.

CONCLUSION

Etrolizumab is a gut-selective, anti-β7 integrin monoclonal antibody that may have therapeutic potential for the treatment of IBD.

Discovery of GDC-0853: A Potent, Selective, and Noncovalent Bruton's Tyrosine Kinase Inhibitor in Early Clinical Development

Bruton's tyrosine kinase (Btk) is a nonreceptor cytoplasmic tyrosine kinase involved in B-cell and myeloid cell activation, downstream of B-cell and Fcγ receptors, respectively. Preclinical studies have indicated that inhibition of Btk activity might offer a potential therapy in autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. Here we disclose the discovery and preclinical characterization of a potent, selective, and noncovalent Btk inhibitor currently in clinical development. GDC-0853 (29) suppresses B cell- and myeloid cell-mediated components of disease and demonstrates dose-dependent activity in an in vivo rat model of inflammatory arthritis. It demonstrates highly favorable safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles in preclinical and Phase 2 studies ongoing in patients with rheumatoid arthritis, lupus, and chronic spontaneous urticaria. On the basis of its potency, selectivity, long target residence time, and noncovalent mode of inhibition, 29 has the potential to be a best-in-class Btk inhibitor for a wide range of immunological indications.

Nonclinical Safety Assessment of Anti-Factor D: Key Strategies and Challenges for the Nonclinical Development of Intravitreal Biologics

PURPOSE

The nonclinical toxicology program described here was designed to characterize the safety profile of anti-factor D (AFD; FCFD4514S, lampalizumab) to support intravitreal (ITV) administration in patients with geographic atrophy (GA).

METHODS

The toxicity of AFD was assessed in a single-dose and 6-month repeat-dose study in monkeys at doses up to 10 mg/eye. Toxicity was assessed by clinical ophthalmic examinations, intraocular pressure measurements, ocular photography, electroretinography, fluorescein angiography, optical coherence tomography, and anatomic pathology.

RESULTS

Systemic exposure to AFD generally increased with the increase in dose level. The increases in mean maximal concentration and area under the curve values were roughly dose proportional. No accumulation of AFD was observed following 10 doses, and drug exposures were not affected by anti-drug antibodies. AFD was locally and systemically well tolerated in monkeys following ITV doses of up to 10 mg/eye. Ocular effects associated with AFD were limited to transient, reversible, dose-related, aqueous cell responses and injection-related, mild, vitreal cell responses. In the 6-month repeat-dose study, 2 monkeys had a nonspecific immune response to AFD that resulted in severe ocular inflammation, attributed to administration of a heterologous (humanized) protein.

CONCLUSIONS

The comprehensive toxicology program in monkeys described here was designed to evaluate the safety profile of AFD and to support multiple ITV injections in the clinic. Administration of a heterologous (humanized) protein presents a challenge, and immunogenicity in nonclinical species is not predictive of immunogenicity in humans. Taken together, the results of the nonclinical program described here support the use of AFD in patients with GA.

Learning and confirming with preclinical studies: modeling and simulation in the discovery of GDC-0917, an inhibitor of apoptosis proteins antagonist

The application of modeling and simulation techniques is increasingly common in the preclinical stages of the drug development process. GDC-0917 [(S)-1-((S)-2-cyclohexyl-2-((S)-2-(methylamino)propanamido)acetyl)-N-(2-(oxazol-2-yl)-4-phenylthiazol-5-yl)pyrrolidine-2-carboxamide] is a potent second-generation antagonist of inhibitor of apoptosis (IAP) proteins that is being developed for the treatment of various cancers. GDC-0917 has low to moderate clearance in the mouse (12.0 ml/min/kg), rat (27.0 ml/min/kg), and dog (15.3 ml/min/kg), and high clearance in the monkey (67.6 ml/min/kg). Accordingly, oral bioavailability was lowest in monkeys compared with other species. Based on our experience with a prototype molecule with similar structure, in vitro-in vivo extrapolation was used to predict a moderate clearance (11.5 ml/min/kg) in humans. The predicted human volume of distribution was estimated using simple allometry at 6.69 l/kg. Translational pharmacokinetic-pharmacodynamic (PK-PD) analysis using results from MDA-MB-231-X1.1 breast cancer xenograft studies and predicted human pharmacokinetics suggests that ED50 and ED90 targets can be achieved in humans using acceptable doses (72 mg and 660 mg, respectively) and under an acceptable time frame. The relationship between GDC-0917 concentrations and pharmacodynamic response (cIAP1 degradation) was characterized using an in vitro peripheral blood mononuclear cell immunoassay. Simulations of human GDC-0917 plasma concentration-time profile and cIAP1 degradation at the 5-mg starting dose in the phase 1 clinical trial agreed well with observations. This work shows the importance of leveraging information from prototype molecules and illustrates how modeling and simulation can be used to add value to preclinical studies in the early stages of the drug development process.

Intracortical visual prosthesis research - approach and progress

Following the early work of Brindley in the late 1960's, the NIH began intramural and extramural funding for stimulation of the primary visual coretex using fine-wire electrodes that are inserted into area VI for the prupose of restoring vision in individuals with blindness. More recently researchers with experience in this projectbecame part of our multi-institutional team with the intention to identify and close technological gaps so that the intracortical approach might be tested in humans on a chronic basis. Our team has formulated an approach for testing a prototype system in a human volunteer. Here, we describe our progress and expectations.

A humanized monoclonal antibody targeting the β7 integrin selectively blocks intestinal homing of T lymphocytes

BACKGROUND AND PURPOSE

rhuMAb Beta7 is a humanized anti-human β7 monoclonal antibody currently in phase I in inflammatory bowel disease. rhuMAb Beta7 binds the β7 subunit of the integrins α4β7 and αEβ7, blocking interaction with their ligands. These integrins play key roles in immune cell homing to and retention in mucosal sites, and are associated with chronic inflammatory diseases of the gastrointestinal tract. The goal of this study was to evaluate the mucosal specificity of rhuMAb Beta7.

EXPERIMENTAL APPROACH

We assessed the effect of murine anti-Beta7 on lymphocyte homing in mouse models of autoimmune disease. We also compared the effect of rhuMAb Beta7 on circulating mucosal-homing versus peripheral-homing T cells in naïve non-human primates.

KEY RESULTS

In cynomolgus monkeys, occupancy of β7 integrin receptors by rhuMAb Beta7 correlated with an increase in circulating β7(+) mucosal-homing lymphocytes, with no apparent effect on levels of circulating β7(-) peripheral-homing lymphocytes. rhuMAb Beta7 also inhibited lymphocyte homing to the inflamed colons of severe combined immunodeficient mice in CD45RB(high) CD4(+) T-cell transfer models. Consistent with a lack of effect on peripheral homing, in a mouse model of experimental autoimmune encephalomyelitis, anti-β7 treatment resulted in no amelioration of CNS inflammation.

CONCLUSIONS AND IMPLICATIONS

The results presented here suggest that rhuMAb Beta7 selectively blocks lymphocyte homing to the gastrointestinal tract without affecting lymphocyte trafficking to non-mucosal tissues. rhuMAb Beta7 provides a targeted therapeutic approach with the potential for a more attractive benefit:risk ratio than currently available inflammatory bowel disease therapies.

Measurement of the e;{+}e;{-}-->bb[over ] Cross Section between sqrt[s]=10.54 and 11.20 GeV

We report e;{+}e;{-}-->bb[over ] cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the SLAC PEP-II e;{+}e;{-} collider. A total relative error of about 5% is reached in more than 300 center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Upsilon(10860) and Upsilon(11020) resonances. In particular we show that their widths may be smaller than previously measured.

Observation of the bottomonium ground state in the decay Upsilon(3S)-->gammaetab

We report the results of a search for the bottomonium ground state etab(1S) in the photon energy spectrum with a sample of (109+/-1) million of Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at Egamma=921.2(-2.8)+2.1(stat)+/-2.4(syst) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Upsilon(3S)-->gammaetab(1S). This photon energy corresponds to an etab(1S) mass of 9388.9(-2.3)+3.1(stat)+/-2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-etab(1S) mass splitting is 71.4(-3.1)+2.3(stat)+/-2.7(syst) MeV/c2. The branching fraction for this radiative Upsilon(3S) decay is estimated to be [4.8+/-0.5(stat)+/-1.2(syst)]x10(-4).

PTEN negatively regulates neural stem cell self-renewal by modulating G0-G1 cell cycle entry

Previous studies have demonstrated that a small subpopulation of brain tumor cells share key characteristics with neural stem/progenitor cells in terms of phenotype and behavior. These findings suggest that brain tumors might contain "cancer stem cells" that are critical for tumor growth. However, the molecular pathways governing such stem cell-like behavior remain largely elusive. Our previous study suggests that the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor gene, one of the most frequently mutated genes in glioblastomas, restricts neural stem/progenitor cell proliferation in vivo. In the present study, we sought to determine the role of PTEN in long-term maintenance of stem cell-like properties, cell cycle entry and progression, and growth factor dependence and gene expression. Our results demonstrate an enhanced self-renewal capacity and G(0)-G(1) cell cycle entry and decreased growth factor dependency of Pten null neural/stem progenitor cells. Therefore, loss of PTEN leads to cell physiological changes, which collectively are sufficient to increase the pool of self-renewing neural stem cells and promote their escape from the homeostatic mechanisms of proliferation control.

Precision measurement of the weak mixing angle in Møller scattering

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) +/- 10(syst)] x 10(-9), leading to the determination of the weak mixing angle sin2(thetaW(eff) = 0.2397 +/- 0.0010(stat) +/- 0.0008(syst), evaluated at Q2 = 0.026 GeV2. Combining this result with the measurements of sin2(thetaW(eff) at the Z0 pole, the running of the weak mixing angle is observed with over 6sigma significance. The measurement sets constraints on new physics effects at the TeV scale.

Visuotopic mapping through a multichannel stimulating implant in primate V1

We report on our efforts to establish an animal model for the development and testing of a cortical visual prostheses. One-hundred-fifty-two electrodes were implanted in the primary visual cortex of a rhesus monkey. The electrodes were made from iridium with an activated iridium oxide film, which has a large charge capacity for a given surface area, and insulated with parylene-C. One-hundred-fourteen electrodes were functional after implantation. The activity of small (2-3) neuronal clusters was first recorded to map the visually responsive region corresponding to each electrode. The animal was then trained in a memory (delayed) saccade task, first with a visual target, then to a target defined by direct cortical stimulation with coordinates specified by the stimulating electrode's mapped receptive field. The SD of saccade endpoints was approximately 2.5 larger for electrically stimulated versus visual saccades; nevertheless, when trial-to-trial scatter was averaged out, the correlation between saccade end points and receptive field locations was highly significant and approached unity after several months of training. Five electrodes were left unused until the monkey was fully trained; when these were introduced, the receptive field-saccade correlations were high on the first day of use (R = 0.85, P = 0.03 for angle, R = 0.98, P < 0.001 for eccentricity), indicating that the monkey had not learned to perform the task empirically by memorizing reward zones. The results of this experiment suggest the potential for rigorous behavioral testing of cortical visual prostheses in the macaque.

Observation of parity nonconservation in møller scattering

We report a measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)] x 10(-9). This first direct observation of parity nonconservation in Møller scattering leads to a measurement of the electron's weak charge at low energy Q(e)(W)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin((2)theta(W)(M(Z))((-)MS)=0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory).

Negative regulation of neural stem/progenitor cell proliferation by the Pten tumor suppressor gene in vivo

The mechanisms controlling neural stem cell proliferation are poorly understood. Here we demonstrate that the PTEN tumor suppressor plays an important role in regulating neural stem/progenitor cells in vivo and in vitro. Mice lacking PTEN exhibited enlarged, histoarchitecturally abnormal brains, which resulted from increased cell proliferation, decreased cell death, and enlarged cell size. Neurosphere cultures revealed a greater proliferation capacity for tripotent Pten-/- central nervous system stem/progenitor cells, which can be attributed, at least in part, to a shortened cell cycle. However, cell fate commitments of the progenitors were largely undisturbed. Our results suggest that PTEN negatively regulates neural stem cell proliferation.

Administering cognitive-behavioral therapy for bulimia nervosa via telemedicine in rural settings

OBJECTIVE

This report describes the therapy of 2 women with bulimia nervosa who were treated using cognitive-behavioral therapy delivered via telemedicine.

METHOD

The telecommunication link was established using a 128-Kbps ISDN switchable data line.

RESULTS

Both cases were treated successfully and were doing well at 1-month follow-up.

DISCUSSION

These cases illustrate that this methodology may make it possible to deliver manual-based psychotherapies to patients with eating disorders in remote areas.

CCAAT/enhancer binding protein alpha assembles essential cooperating factors in common subnuclear domains

The transcription factor CCAAT/enhancer binding protein alpha (C/EBP alpha) is the DNA binding subunit of a multiprotein complex that regulates the pituitary-specific GH promoter. C/EBP alpha is absent from the GHFT1-5 pituitary progenitor cell line in which ectopic C/EBP alpha expression leads to activation of the otherwise dormant GH promoter. Transcriptional regulatory complexes are commonly envisaged as assembling from components that evenly diffuse throughout the nucleoplasm. We show that C/EBP alpha, expressed in GHFT1-5 cells as a fusion with color variants of the green fluorescent protein (GFP), concentrated specifically at peri-centromeric chromosomal domains. Although we found the CREB-binding protein (CBP) to activate C/EBP alpha-dependent transcription, CBP was absent from the pericentromeric chromatin. C/EBP alpha expression was accompanied by the translocation of endogenous and ectopically expressed CBP to pericentromeric chromatin. The intranuclear recruitment of CBP required the transcriptional activation domains of C/EBP alpha. C/EBP alpha also caused GFP-tagged TATA binding protein (TBP) to relocate to the Hoechst-stained domains. The altered intranuclear distribution of critical coregulatory factors defines complexes formed upon C/EBP alpha expression. It also identifies an organizational activity, which we label "intranuclear marshalling," that may regulate gene expression by determining the cooperative and antagonistic interactions available at specific nuclear sites.

Role of C5a in multiorgan failure during sepsis

In humans with sepsis, the onset of multiorgan failure (MOF), especially involving liver, lungs, and kidneys, is a well known complication that is associated with a high mortality rate. Our previous studies with the cecal ligation/puncture (CLP) model of sepsis in rats have revealed a C5a-induced defect in the respiratory burst of neutrophils. In the current CLP studies, MOF occurred during the first 48 h with development of liver dysfunction and pulmonary dysfunction (falling arterial partial pressure of O(2), rising partial pressure of CO(2)). In this model an early respiratory alkalosis developed, followed by a metabolic acidosis with increased levels of blood lactate. During these events, blood neutrophils lost their chemotactic responsiveness both to C5a and to the bacterial chemotaxin, fMLP. Neutrophil dysfunction was associated with virtually complete loss in binding of C5a, but binding of fMLP remained normal. If CLP animals were treated with anti-C5a, indicators of MOF and lactate acidosis were greatly attenuated. Under the same conditions, C5a binding to blood neutrophils remained intact; in tandem, in vitro chemotactic responses to C5a and fMLP were retained. These data suggest that, in the CLP model of sepsis, treatment with anti-C5a prevents development of MOF and the accompanying onset of blood neutrophil dysfunction. This may explain the protective effects of anti-C5a in the CLP model of sepsis.

Spontaneous candida mediastinitis diagnosed by endoscopic ultrasound-guided, fine-needle aspiration

Candida mediastinitis is a rare clinical entity associated with high mortality and morbidity. It is emerging as an important clinical entity, probably due to increased recognition of candida as a significant pathogen in mediastinitis. Candida mediastinitis is usually associated with cardiothoracic surgery, esophageal perforation, and head and neck infections. Optimal therapy for candida mediastinitis remains undefined. Aggressive, combined surgical debridement and antifungal therapy appears to be the most effective of available therapies. We report a case of spontaneous candida mediastinitis diagnosed by endoscopic ultrasound-guided, fine-needle aspiration and successfully treated with oral antifungal therapy alone.

Effects of glutamine on head and neck squamous cell carcinoma

Glutamine supplements are being studied as protectants against the mucositis associated with radiation therapy of head and neck squamous cell carcinoma. Glutamine is an important amino acid for the maintenance of healthy gut function and nitrogen transport. It is also a preferred energy source for many types of tumors through an altered Krebs cycle. The effects of glutamine supplements on the growth of head and neck squamous cell carcinoma have not been studied. Eighteen nude mice were implanted with one established cell line, and 18 were implanted with another. The mice were paired and fed either a glutamine-rich or a glutamine-poor diet. There was not a statistically significant difference in the growth rates of the xenografts or in the weight gain of the mice between the diet groups. These findings are encouraging for the continued use of glutamine supplements in patients with head and neck squamous cell carcinoma.

Molecular characterization of autosomal recessive chronic granulomatous disease caused by a defect of the nicotinamide adenine dinucleotide phosphate (reduced form) oxidase component p67-phox

Chronic granulomatous disease (CGD) is a rare inherited disorder of phagocytes in which defective production of microbicidal oxidants leads to severe recurrent infections. CGD is caused by mutations in any of 4 genes encoding components of nicotinamide adenine dinucleotide phosphate (reduced form; NADPH) oxidase, the multisubunit enzyme that produces the precursor of these oxidants, superoxide. Approximately 5% of CGD patients have an autosomal recessive form of disease caused by a severe deficiency of p67-phox, a 526-amino acid subunit of the oxidase that appears to regulate electron transport within the enzyme. Here we report the biochemical and molecular characterization of 6 unrelated kindreds with p67-phox deficiency. These studies show that, as in gp91-phox and p22-phox deficiencies, the p67-phox CGD patients show a high degree of heterogeneity in the genetic defects that underlie their disease. Five different mutant alleles were identified: (1) a nonsense mutation in exon 4 (C(304) --> T); (2) a 5-nucleotide (nt) deletion in exon 13 (nts 1169-1173); (3) a splice mutation in the first nucleotide of intron 4 (G --> A); (4) a deletion of 1 nt in exon 9 (A(728)); and (5) a 9-nt in-frame deletion in exon 2 (nts 55-63). The splice mutation was seen in 3 unrelated kindreds, while the 5-nt deletion was seen in 2 apparently unrelated families (both of Palestinian origin). Homozygosity was present in 4 of the kindreds, 2 of which had consanguineous parentage. In the isolated neutrophils of each of the affected patients in the 6 kindreds, there was no measurable respiratory burst activity and no p67-phox protein detected by immunoblot analysis. The level of 67-phox mRNA was less than 10% of normal in the mononuclear leukocytes from 3 of the 4 patients analyzed by Northern blot studies. Thus, this heterogeneous group of mutations in p67-phox all lead to marked instability of mRNA or protein (or both) that results in the complete loss of NADPH oxidase activity.

Clinical application of a new disposable lithotripter: a prospective multicenter study

BACKGROUND

Mechanical lithotripsy has become a well-accepted method of bile duct stone fragmentation and removal. The Olympus lithotripter (Olympus American, Melville, NY) is the standard reusable lithotripter at the institutions that participated in this study. A disposable device with a preassembled pistol grip may perform equally well and facilitate operation.

METHODS

Twenty patients with bile duct stones were evaluated as part of a multicenter prospective study. Data were obtained regarding stone size and number, bile duct diameter, and configuration, ease of cannulation, basket function, stone capture and crushing success, and complications.

RESULTS

The maximum stone size averaged 16.5 +/- 1.2 mm (range 10 to 30 mm). Sixteen patients had multiple stones (median 5, range 2 to 12). The mean bile duct diameter was 20.5 +/- 1.5 mm (range 12 to 38 mm). Cannulation was successful in all within 5 attempts. Basket deployment failed in 1 patient because of stone size and the basket was misshapen in 14. Bile duct clearance was complete in 16 subjects (80%), incomplete in 2 patients, and failed in 2 patients. Abnormal duct configuration (sigmoid, stricture) was noted in 2 of 4 patients with failed capture and 7 of 16 patients with successful clearance. No statistically significant difference was observed between the bile duct diameter, maximum stone size, number of stones, and successful clearance.

CONCLUSION

The disposable lithotripter is easy to use and, compared with the published results for the reusable lithotripter, performs almost as well.

Traumatic occupational fatalities in the retail industry, United States 1992-1996

BACKGROUND

Retail is a growing economic sector and employs an increasing number of the overall workforce, yet little is known about the incidence and characteristics of work-related deaths in the retail industry.

METHODS

Workplace deaths were examined using the Census of Fatal Occupational Injuries from 1992 through 1996. Occupational fatality rates were calculated by age, gender, and type of establishment, and characteristics of occupational deaths in the retail industry were compared to other industries.

RESULTS

Liquor stores had the highest work-related fatality rates in the retail industry. The two leading causes of death in the retail industry were violence (69.5%) and motor vehicle crashes (19.3%). Females, younger, minority, and foreign-born workers were more likely to be killed in retail than other industries. Deaths in the retail industry were more likely to be in small businesses, after normal business hours, and in urban settings.

DISCUSSION

Workers in the retail industry were at lower risk of most types of workplace deaths but had a markedly increased risk of violent death than workers in other industries.

Phenotypic and genotypic heterogeneity in familial Milroy lymphedema

Familial Milroy lymphedema (ML) is classified as an autosomal dominant disorder characterized by peripheral edema of the lower extremities at birth or in early childhood. The variety of phenotypes are not well described, and the genomic location and functional expression of the gene or genes underlying this and related familial lymphedema syndromes remain largely unknown. In this collaborative study between the University of Arizona and the University of São Paulo, we collected clinical pedigrees on 6 ML families, carried out clinical examination of affected and unaffected individuals, and, in representative affected members of two of the families performed dynamic lymphangioscintigraphy (LAS) of the lower and upper limbs to delineate further the ML lymphangiodysplastic phenotype. To localize the gene for ML, we conducted a genome-wide search in 4 of the families using 387 polymorphic dinucleotide-repeat markers at approximate 10 cM spacing in 54 subjects (affected, unaffected bloodline relatives, and spouses). In all 6 families (86 subjects), we specifically examined the suggested linkage to the vascular endothelial growth factor (VEGF)-C receptor (Flt4) gene localized to the chromosome region 5q34-q35. The findings provide evidence for a spectrum of ML clinical and LAS phenotypes and also suggest ML locus heterogeneity.

Metabolic brain mapping in Alzheimer's disease using proton magnetic resonance spectroscopy

Alzheimer's disease (AD) is a progressive disorder associated with disruption of neuronal function and neuronal loss. N-acetylaspartate (NAA) is a marker of neuronal content and can be assessed using proton (1H) magnetic resonance spectroscopy (MRS). We utilized 1H-MRS (two-dimensional chemical-shift imaging) to assess amplitudes and areas of NAA, as well as choline moieties (Cho), creatine (Cr) and myo-inositol (mI), in 15 AD patients compared with 14 control subjects. Voxels were classified as predominantly cortical gray matter (CGM), subcortical gray matter (SGM), or white matter (WM). Compared with control subjects, AD patients exhibited decreased NAA/Cho and NAA/Cr amplitudes, whereas an increase was observed in Cho/Cr and in amplitude ratios involving mI. Area ratios were significant in the same direction for NAA/Cho, NAA/Cr, mI/Cr and mI/NAA. No significant effects of tissue type were observed; however, significant group x tissue type interactions were noted for Cho/Cr and mI/Cr amplitudes. Our study confirms that 1H-MRS can identify distinct physicochemical alterations in AD patients, reflecting membrane changes and diminished neuronal function. These alterations can be used as longitudinal markers for the disease.

Association between genetic polymorphisms of the beta2-adrenoceptor and response to albuterol in children with and without a history of wheezing

The beta2-adrenergic receptor (beta2AR) agonists are the most widely used agents in the treatment of asthma, but the genetic determinants of responsiveness to these agents are unknown. Two polymorphic loci within the coding region of the beta2AR have been recently described at amino acids 16 and 27. It has been reported that glycine at codon 16 (Gly-16) is associated with increased agonist-promoted downregulation of the beta2AR as compared with arginine-16 (Arg-16). The form of the receptor with glutamic acid at codon 27 (Glu-27), on the other hand, has been shown to be resistant to downregulation when compared with glutamine-27 (Gln-27), but only when coexpressed with Arg-16. To assess if different genotypes of these two polymorphisms would show differential responses to inhaled beta2AR agonists, we genotyped 269 children who were participants in a longitudinal study of asthma. Spirometry was performed before and after administration of 180 microg of albuterol, and a positive response was considered an increase of >15.3% predicted FEV1. There was marked linkage disequilibrium between the two polymorphisms, with 97.8% of all chromosomes that carried Arg-16 also carrying Gln-27. When compared to homozygotes for Gly-16, homozygotes for Arg-16 were 5.3 times (95% confidence interval 1.6-17.7) and heterozygotes for beta2AR-16 were 2.3 times (1.3-4.2) more likely to respond to albuterol, respectively. Similar trends were observed for asthmatic and nonasthmatic children, and results were independent of baseline lung function, ethnic origin, and previous use of antiasthma medication. No association was found between the beta2AR-27 polymorphism and response to albuterol. These results may explain some of the variability in response to therapeutic doses of albuterol in children.

Effects of experimental hemosiderosis on intestinal morphology, permeability, and tissue iron content

Effects of iron overload on intestinal function and structure are unknown and were, therefore, investigated. Sprague-Dawley rats were randomized into an iron-overloaded group, which received a single subcutaneous injection of 1.2 g/kg elemental iron-dextran complex, and placebo-treated pair-fed controls. Animals were studied after a 10-month observation period. Intestinal permeability was assessed by measuring the urinary excretion of lactulose, rhamnose, and mannitol after oral administration. In addition, tissue nonheme iron content was measured, and histologic examination and morphometric measurements were carried out. The chronic iron-overloaded group showed a significant increase in intestine tissue iron content and stainable iron in the submucosa and muscularis propria and adipose tissue of the small intestine and lamina propria and muscularis mucosa of the large intestine. There was a significant decrease in the crypt depths without discernible change in the intestine permeability to any of the markers used. In addition, the iron-overloaded animals showed a significant number of iron-laden cells, which primarily consisted of macrophages, fibroblasts, myocytes, and adipocytes. In contrast, no iron-laden cells were present in tissues obtained from the normal control group. Thus, chronic experimental iron overload in rats leads to significant morphologic, but no permeability, alterations of the alimentary tract.

Migration of epithelium during phenytoin-dependent gingival overgrowth in mice

A small cavity was made in the mesiopalatal area of the maxillary first molar adjacent to the gingiva. Mice were maintained on 40 mg/kg phenytoin (or on diluent for control) by daily intraperitoneal injections. After 9 weeks, light microscopic observations revealed that in experimental mice, epithelial cells migrated towards the cavity and covered it. In controls, epithelial cell migration towards the cavity did not occur. For scanning electron microscopic (SEM) studies, specimens were fixed in 4% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2, for 2 hours, dehydrated, critical point dried and coated with gold. The surface of the outer gingival epithelium of experimental and of control mice showed a honeycomb arrangement of the microridges suggesting their keratinized nature. Epithelial cells lining the cavity showed well marked macroridges along their borders. Parallel microridges were observed on the upper surface of these cells suggesting that they were non-keratinized. It was concluded that the migrating epithelial cells, that covered the cavity during phenytoin-dependent gingival overgrowth, were of the non-keratinized type.

Study of the major phenotype of large granular T-cell lymphoproliferative disorder

Six cases of large granular T-cell lymphoproliferative disorder with a selected immunophenotype (CD3+, CD4-, CD8+, CD16+) were studied to characterize a homogeneous group of patients. It was found that most of these patients did not exhibit the clinical features frequently described in large granular T-cell lymphoproliferative disorder--recurrent infection, rheumatoid arthritis, and splenomegaly. The laboratory tests usually positive in large granular T-cell lymphoproliferative disorder, including rheumatoid factor and anti-nuclear antibodies, also were frequently negative. The pathognomonic features were found to be neutropenia and large granular lymphocytosis with positive killer cell markers. All six cases showed T-cell receptor gene rearrangement that indicated a monoclonal proliferation of lymphoid cells, which were natural killer-like T cells by immunophenotyping. B cells were essentially absent in all cases. It should be emphasized that bone marrow aspirates are as informative as peripheral blood samples for the diagnosis of large granular T-cell lymphoproliferative disorder; indeed, phenotypes of blood and marrow in one case were identical in terms of percentages of markers. In this selected group of patients, the clinical courses were indolent with uncomplicated outcomes. In three patients, chemotherapy did not induce an obvious clinical response, but all patients' conditions remained stable with only supportive care.

Effect of concurrent chest pain assessment on retrospective reports by cardiac patients

The purpose of this study was to examine the effect of a concurrent record of chest pain episodes on later completeness and accuracy of verbal recall. Patients included 23 men and eight women, ages 43 to 76 years from a private cardiology practice who were randomized into experimental (n = 16) and control (n = 15) groups. Following an initial interview, experimental patients were instructed in using a Chest Discomfort Diary in the home setting to record eight categories of information about each episode of chest pain experienced during the next 7 to 10 days. At the end of that time, both groups were interviewed about a specific typical episode of chest pain that had occurred; patients who did not have chest pain during the study period described an episode experienced prior to the initial interview. Experimental patients recalled their chest pain more completely than controls (P = 0.007), whether it had occurred during or prior to the study period. Experimental patients who had pain (n = 11), and thus actually used the diary, accurately recalled the duration, intensity, description, and treatment of the typical episode but were often inaccurate regarding their mood and the total number of episodes they had experienced. The findings suggest that a concurrent diary offers one method of teaching patients how to report their chest pain symptoms and may improve the completeness and accuracy of those reports.

Identification and certification of extracorporeal membrane oxygenation specialists in the United States

Extracorporeal membrane oxygenation (ECMO) is a highly specialized technique widely practiced in many hospitals. Despite the proliferation of ECMO, little information has been generated relating to ECMO specialists, a new professional group responsible for managing the extracorporeal life support (ELS) system. A telephone survey of ECMO centers in the United States was conducted to determine the number of ECMO specialists, team composition by profession, and clinical components of ECMO specialist certification. Data were obtained in May 1991 from all 63 (100%) active ELS centers. The survey found that the average ECMO program performs 3,770 +/- 1,019 clinical hours of ELS per year with a team of 23 +/- 11 specialists. There are 1,431 practicing ECMO specialists in the United States: 73% registered nurses, 22% respiratory therapists, and 5% others. Most ECMO specialist teams (56%) are comprised of a single profession, with 44% of programs using a mixture of professions. The average ECMO specialist manages the ELS system 171 +/- 91 hr/yr. Thirty-six (57%) programs have a mean yearly clinical requirement of 77 +/- 23 ELS hours per specialist. These results represent the first complete report identifying the number of ECMO specialists in the United States. In addition, program demographics demonstrate variability in ECMO experience and certification requirements.

Functional projections from striate cortex and superior temporal sulcus to the nucleus of the optic tract (NOT) and dorsal terminal nucleus of the accessory optic tract (DTN) of macaque monkeys

The nucleus of the optic tract (NOT) and the dorsal terminal nucleus of the accessory optic tract (DTN) have been recognized to be relevant structures for optokinetic and vestibuloocular reflexes. NOT-DTN neurons relay visual information to the vestibular nuclei via the nucleus prepositus hypoglossi and to the flocculus via the dorsal cap of the inferior olive. It has been previously shown that in carnivores the NOT-DTN receives information from primary visual cortical areas in addition to the direct retinal input. In this study we demonstrate the presence and some functional characteristics such as latency and evicacy of considerable cortical projections to the NOT-DTN in macaque monkeys. In anaesthetized and paralyzed monkeys NOT-DTN neurons were identified physiologically and tested for cortical input by electrical stimulation in various cortical areas. Successful sites of stimulation to activate NOT-DTN neurons orthodromically lie in the primary visual cortex (V1) and in the motion-processing areas in the superior temporal sulcus (STS). In contrast, electrical stimulation in area V4 and in parietal areas in most cases did not yield orthodromic responses. Overall latencies of action potentials elicited by stimulation in V1 were 0.5 ms longer than those elicited from STS. These short latency differences between V1 and STS stimulation suggest a direct projection from both V1 and STS to the NOT-DTN. The physiological results were supported by the results of anatomical experiments by using horseradish peroxidase as anterograde tracer. Both injections into V1 and into the lower bank of STS resulted in anterogradely labelled fibers and terminals around the recording sites of direction-specific NOT-DTN neurons. This paper is a first step in clarifying the significance of corticofugal projections from individual areas involved in the analysis of visual motion for the optokinetic reflex.

Measurement of dentin permeability and wetness by use of the Periotron device

The ability of the Periotron device to measure changes in dentin permeability and wetness was evaluated by use of extracted human teeth in vitro. Pulpal pressures were varied from zero to 40 cm H2O for simulation of different pulpal tissue pressures. Non-physiologic pulpal pressures of 703 cm H2O were used for comparison of dentin permeability measurements made with the Periotron device with those made using micropipettes. Measurements made with the Periotron device correlated well with methods used previously for measurement of dentin permeability. The shear bond strength of Scotchbond 2/Silux was measured 24 h after being bonded to dentin held at zero pulpal pressure. There was an inverse correlation between the shear bond strengths of Scotchbond 2/Silux and Periotron values, suggesting that increased wetness decreases the bond strength of that system. The Periotron device offers a new, simple, convenient measure of dentin surface wetness which may be useful in dentin bonding studies.

Cardiovascular effects of caffeine therapy in preterm infants

Theophylline therapy increases left ventricular output in preterm infants by a combination of positive inotropic and chronotropic effects. The cardiovascular effects of caffeine were evaluated in 20 clinically stable preterm infants. Ten infants received intravenous caffeine citrate with a loading dose of 20 mg/kg and a maintenance dose of 5 mg/kg every 24 hours, and 10 infants were control subjects. Left ventricular output, stroke volume, and heart rate were measured by using a combination of two-dimensional and pulsed Doppler echocardiography and mean arterial blood pressure by oscillometry (Dinamap, Critikon, Division of McNeil Laboratories, Irvine, Calif) before the start and on days 1, 2, 3, and 7 of caffeine therapy and 7 days after discontinuation of therapy. Compared with controls, left ventricular output and stroke volume were significantly increased on days 1 to 7 of caffeine therapy. Caffeine led to an increase in the mean arterial blood pressure on the first 3 days of therapy, but the heart rate did not change. These data indicated that caffeine administration leads to a significant increase in left ventricular output in preterm infants and that this inotropic effect is accompanied by a pressor effect.

Deglycosylation of mucin from LS174T colon cancer cells by hydrogen fluoride treatment

Mucin from xenografts of LS174T human colon cancer cells was treated with anhydrous HF for 1 h at 0 degree C to give a product (HFA) with over 80% of the glucosamine and hexose removed, but retaining some galactosamine, and for 3 h at room temperature to give a product (HFB) devoid of carbohydrate. Rabbit antibodies against HFA bound to HFA much more than to HFB, and bound to native mucin to an intermediate extent. Antibodies to HFB bound to HFB more than to HFA, and did not bind to native mucin. Both HFA and native mucin bound a number of lectins, but HFB did not. By SDS/polyacrylamide-gel electrophoresis and size-exclusion h.p.l.c., native mucin and HFA are of apparent molecular mass greater than 400 kDa, whereas HFB is heterogeneous and of low molecular mass. On Western blots, antibody to HFA detected both high-molecular-mass mucin and a 90 kDa protein in homogenates of LS174T cells. Antibody to HFB detected a major 70 kDa band as well as higher-molecular-mass species. In tissue sections of normal colon and colon cancers, antibody to HFA showed both cytoplasmic and extracellular staining, whereas antibody to HFB generally stained only cytoplasmic antigens. These results indicate that anti-HFB antibody is specific for apo-mucin, whereas anti-HFA antibody is specific for GalNAc-apo-mucin.