Detection of oxidative DNA damage in oesophageal biopsies of patients with reflux symptoms and normal pH monitoring

BACKGROUND

Gastro-oesophageal reflux has been shown to induce oxidative DNA damage.

AIM

To determine whether oxidative DNA damage, detected in oesophageal biopsies by simple immunohistochemical staining, correlates with gastro-oesophageal reflux disease as determined by pH monitoring.

METHODS

The study included 47 patients with reflux symptoms who had oesophageal biopsy and 24-h pH monitoring studies performed within 3 months of each other with no variation in treatment in the time between the two procedures. Sections of formalin-fixed and paraffin-embedded oesophageal biopsies were stained for 8-hydroxy-2'-deoxyguanosine using the standard immunoperoxidase method. Positive nuclear immunoreactivity was considered to indicate oxidative DNA damage.

RESULTS

Seven (33%) of the 21 cases with normal 24-h pH monitoring results were negative for oxidative DNA damage, compared with only two (8%) of the 26 cases with abnormal 24-h pH results (P=0.058, two-sided Fisher's exact test). Five of the patients with normal 24-h pH results had oesophageal biopsies performed within 24 h of the monitoring procedure and, of these, four (80%) were positive for oxidative DNA damage, including a case in which both biopsy and 24-h pH monitoring were performed on the same day whilst the patient was on proton pump inhibitor therapy. All cases with normal 24-h pH results and positive oxidative DNA damage showed features of reflux on routine morphological evaluation.

CONCLUSIONS

Oxidative DNA damage can occur in the absence of acid reflux and despite adequate antisecretory therapy. This may indicate that other agents, such as bile, can induce oxidative DNA damage in an acid-suppressed environment. The significant discordance between oxidative DNA damage and 24-h pH results makes the determination of oxidative DNA damage a poor surrogate marker for 24-h pH monitoring.

Molecular effects of novel mutations in Hesx1/HESX1 associated with human pituitary disorders

The homeobox gene Hesx1/HESX1 has been implicated in the establishment of anterior pattern in the central nervous system (CNS) in a number of vertebrate species. Its role in pituitary development has been documented through loss-of-function studies in the mouse. A homozygous missense point mutation resulting in a single amino acid substitution, Arg160Cys (R160C), is associated with a heritable form of the human condition of septo-optic dysplasia (SOD). We have examined the phenotype of affected members in this pedigree in more detail and demonstrate for the first time a genetic basis for midline defects associated with an undescended or ectopic posterior pituitary. A similar structural pituitary abnormality was observed in a second patient heterozygous for another mutation in HESX1, Ser170Leu (S170L). Association of S170L with a pituitary phenotype may be a direct consequence of the HESX1 mutation since S170L is also associated with a dominant familial form of pituitary disease. However, a third mutation in HESX1, Asn125Ser (N125S), occurs at a high frequency in the Afro-Caribbean population and may therefore reflect a population-specific polymorphism. To investigate the molecular basis for these clinical phenotypes, we have examined the impact of these mutations on the regulatory functions of HESX1. We show that Hesx1 is a promoter-specific transcriptional repressor with a minimal 36 amino acid repression domain which can mediate promoter-specific repression by suppressing the activity of homeodomain-containing activator proteins. Mutations in HESX1 associated with pituitary disease appear to modulate the DNA-binding affinity of HESX1 rather than its transcriptional activity. Wild-type HESX1 binds a dimeric homeodomain site with high affinity (Kd 31 nM) whilst HESX1(S170L) binds with a 5-fold lower activity (Kd 150 nM) and HESX1(R160C) does not bind at all. Although HESX1(R160C) has only been shown to be associated with the SOD phenotype in children homozygous for the mutation, HESX1(R160C) can inhibit DNA binding by wild-type HESX1 both in vitro and in vivo in cell culture. This dominant negative activity of HESX1(R160C) is mediated by the Hesx1 repression domain, supporting the idea that the repression domain is implicated in interactions between homeodomain proteins. Our data suggest a possible molecular paradigm for the dominant inheritance observed in some pituitary disorders.

Heterozygous HESX1 mutations associated with isolated congenital pituitary hypoplasia and septo-optic dysplasia

We have previously shown that familial septo-optic dysplasia (SOD), a syndromic form of congenital hypopituitarism involving optic nerve hypoplasia and agenesis of midline brain structures, is associated with homozygosity for an inactivating mutation in the homeobox gene HESX1/Hesx1 in man and mouse. However, as most SOD/congenital hypopituitarism occurs sporadically, the possible contribution of HESX1 mutations to the aetiology of these cases is presently unclear. Interestingly, a small proportion of mice heterozygous for the Hesx1 null allele show a milder SOD phenocopy, implying that heterozygous mutations in human HESX1 could underlie some cases of congenital pituitary hypoplasia with or without midline defects. Accordingly, we have now scanned for HESX1 mutations in 228 patients with a broad spectrum of congenital pituitary defects, ranging in severity from isolated growth hormone deficiency to SOD with panhypopituitarism. Three different heterozygous missense mutations were detected in individuals with relatively mild pituitary hypoplasia or SOD, which display incomplete penetrance and variable phenotype amongst heterozygous family members. Gel shift analysis of the HESX1-S170L mutant protein, which is encoded by the C509T mutated allele, indicated that a significant reduction in relative DNA binding activity results from this mutation. Segregation analysis of a haplotype spanning 6.1 cM, which contains the HESX1 locus, indicated that only one HESX1 mutation was present in the families containing the C509T and A541G mutations. These results demonstrate that some sporadic cases of the more common mild forms of pituitary hypoplasia have a genetic basis, resulting from heterozygous mutation of the HESX1 gene.

Instillation of allogeneic lung antigen-presenting cells deficient in expression of major histocompatibility complex class I or II antigens have differential effects on local cellular and humoral immunity and on pathology in recipient murine lungs

Recognition of allogeneic major histocompatibility complex (MHC) molecules expressed on donor lung antigen-presenting cells (APCs) by host T lymphocytes is believed to stimulate lung allograft rejection. However, the specific roles of donor MHC molecules in the rejection response is unknown. We report a murine model in which instilling allogeneic lung APCs into recipient lungs induces pathology analogous to acute rejection, and the production of interferon (IFN)-gamma, immunoglobulin (Ig) G2a, and alloantibodies in recipient lungs. Using allogeneic lung APCs (C57BL/6, I-a(b), H-2(b)) deficient in MHC class I, II, or both for instillation into lungs of BALB/c mice (I-a(d), H-2(d)), the purpose of the current study was to determine the specific roles of donor MHC molecules in stimulating local alloimmune responses. The data show that MHC class I or II on donor APCs induced IFN-gamma and IgG2a synthesis locally, though less than that induced by wild-type cells. Both MHC class I and II were required to induce alloantibody production. Instillation of wild-type or class I- or class II-deficient APCs induced comparable pathologic lesions in recipient lungs, and more severe than that induced by MHC-deficient cells. These data show that donor MHC class I and II molecules have differential effects in the stimulation of local alloimmune responses.

The new hospice compliance plan: defining and addressing risk areas. Part 3

The recently released OIG guidelines to ensure compliance with federal and state statutes, rules, and regulations, and private-payor health care program requirements provide a blueprint for developing such programs. This is the last of three installments that focus specifically on the 28 risk areas identified in the guidance and offer strategies for incorporating them in a hospice compliance program. The authors have organized the 28 risk areas under 9 topic domains to simplify the task of tackling the guidance. This article covers the areas of nursing home care, marketing, and Conditions of Participation.

The new hospice compliance plan: defining and addressing risk areas. Part 2

The Department of Health and Human Services' (HHS) Office of the Inspector General (OIG), has advised hospices and other health care providers to formulate effective controls to ensure compliance with federal and state statutes, rules, and regulations, and private-payor health care program requirements. This is the second of three installments that focus specifically on the 28 risk areas identified in the guidance and offer strategies for incorporating them in a hospice compliance program. This article covers the areas of Expensive Care, Documentation, Interdisciplinary Group, and Kickbacks.

The new hospice compliance plan: defining and addressing risk areas

The Department of Health and Human Services' (HHS) Office of the Inspector General (OIG), has advised hospices and other health care providers to formulate effective controls to ensure compliance with federal and state statutes, rules, and regulations, and private-payor health care program requirements. The recently released guidelines provide a blueprint for developing such programs. This is the first of four installments that focus specifically on the 28 risk areas identified in the guidance and offer strategies for incorporating them in a hospice compliance program. The authors have organized the 28 risk areas under 9 topic domains to simplify the task of tackling the guidance. This article covers the first two areas: Admission/Certification/Recertification and Billing.

Mutations in a new gene in Ellis-van Creveld syndrome and Weyers acrodental dysostosis

Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive skeletal dysplasia characterized by short limbs, short ribs, postaxial polydactyly and dysplastic nails and teeth. Congenital cardiac defects, most commonly a defect of primary atrial septation producing a common atrium, occur in 60% of affected individuals. The disease was mapped to chromosome 4p16 in nine Amish subpedigrees and single pedigrees from Mexico, Ecuador and Brazil. Weyers acrodental dysostosis (MIM 193530), an autosomal dominant disorder with a similar but milder phenotype, has been mapped in a single pedigree to an area including the EvC critical region. We have identified a new gene (EVC), encoding a 992-amino-acid protein, that is mutated in individuals with EvC. We identified a splice-donor change in an Amish pedigree and six truncating mutations and a single amino acid deletion in seven pedigrees. The heterozygous carriers of these mutations did not manifest features of EvC. We found two heterozygous missense mutations associated with a phenotype, one in a man with Weyers acrodental dysostosis and another in a father and his daughter, who both have the heart defect characteristic of EvC and polydactyly, but not short stature. We suggest that EvC and Weyers acrodental dysostosis are allelic conditions.

Nucleotide sequence and characterization of human papillomavirus type 83, a novel genital papillomavirus

Studies of human papillomaviruses (HPV) are hampered by the lack of a conventional culture system, because HPV completes its life cycle only in fully differentiated human tissue. To overcome this obstacle, the athymic mouse xenograft system has been used to study the pathogenesis of a limited number of HPV types. We recently reported the propagation of a novel HPV type in the mouse xenograft system and the cloning of its genome. Consensus primer PCR had previously identified this virus as MM7, LVX82, or PAP291. Here we report the nucleotide sequence of the 8104-bp genome of this virus, now called HPV 83. HPV 83 is most closely related to HPV 61 and HPV 72, placing it in the papillomavirus genome homology group A3. Based on limited epidemiological data, the histological appearance of infected human foreskin implants, and the structure of the predicted HPV 83 E7 protein, this virus is probably of at least intermediate cancer risk. Like other papillomaviruses, HPV 83 produces an E1 E4, E5 transcript, but the position of the splice acceptor differs from that of other HPVs. The presence of an E5 open reading frame in the HPV 83 genome is uncertain; the most likely candidate to be the HPV 83 E5 protein has some structural similarity to the bovine papillomavirus 1 E5 oncoprotein, and is unlike most other HPV E5 proteins. HPV 83 is a relatively prevalent genital papillomavirus that has the largest genome of any characterized HPV and several other novel structural features that merit further study.

Receptor/ligand interactions between Cryptosporidium parvum and the surface of the host cell

The ability of membrane antigens on sporozoites of the intestinal pathogen, Cryptosporidium parvum, to bind host cell surface antigens was investigated. A novel membrane-associated protein of approximately 47 kDa, designated CP47, was found to possess significant binding affinity for the surface of both human and animal ileal cells. This protein was purified by a combination of anion-exchange chromatography on FPLC and immunoaffinity chromatography. Purified CP47 demonstrated competitive binding with parasite-associated membrane antigens to membranes of HCT-8 and ileal cells in a dose-dependent manner. Furthermore, the binding activity of CP47 was found to be Mn2+-sensitive, and was completely inhibited in the presence of 10 mM MnCl2. These results were consistent with earlier findings demonstrating the inhibitory effect of Mn2+ ions on Cryptosporidium infection both in vitro and in vivo (Nesterenko et al., Biol. Trace Elem. Res. 56 (1997) 243-253). Immunoelectron microscopy using gold-conjugated antibodies revealed CP47 to be localized at the apical end of the sporozoites. A single protein with an electrophoretic mobility of 57 kDa was purified from host cell membranes using CP47-Affigel. Similarly, affinity purification of this protein was abrogated in the presence of Mn2+. These data suggest that a novel parasite protein, CP47, may play an important role in sporozoite/host cell attachment.

Sugar, drinks, deprivation and dental caries in 14-year-old children in the north west of England in 1995

OBJECTIVES

To examine associations between dental caries and reported drink consumption.

DESIGN

A cross-sectional caries prevalence study including reported drink consumption.

SETTING

Secondary schools across the former North Western Region of England.

SUBJECTS

A random sample of 6,014, 14-year-old children.

RESULTS

The mean DMFT of the sample was 2.74. The reported mean weekly consumption of cans of carbonated drinks was 5.66, with a range of zero to 42. There was a significant gender difference in drink consumption and a significant correlation between the reported weekly consumption of cans of carbonated drinks and DMFT. Logistic regression analysis showed tea drinkers had a significantly lower DMFT than coffee drinkers and that this effect was independent of the addition of sugar and the number of cans of drink consumed. Reported use of sugar-free carbonated drinks was not associated with better dental health.

CONCLUSIONS

Reported consumption of sugared drinks and carbonated drinks was associated with significantly higher levels of dental caries. Drinking tea was associated with lower levels of caries. Sugar-free drinks were not associated with better dental health.

Primary-care delivery for sickle cell patients in rural Georgia using telemedicine

BACKGROUND

Advances in newborn screening and pediatric management of sickle cell disease have resulted in patients living well into adulthood. For adults, preventive care and medication monitoring are crucial for optimal health maintenance. The Medical College of Georgia (MCG) in Augusta provides consultative services and comprehensive medical care to about 1200 sickle cell patients residing in middle and southern Georgia. An increase in the demand for clinical services in this patient population has resulted in expansion of sickle cell outreach efforts throughout the state.

OBJECTIVE

A telemedicine clinic for adult sickle cell patients was established in order to meet the growing clinical demands.

METHODS

An on-site outreach clinic was introduced in the target area. After 10 months of operation, a monthly telemedicine clinic was offered to patients as an option for routine medical follow-up. A clinic model was used, with scheduled appointments and a public health nurse assisting at the remote site. Phlebotomy and laboratory services enhanced the telemedicine encounter.

RESULTS

Over a 12-month period, 52 encounters for 28 patients from 17 medically underserved counties were completed. All patients were African-American, and 89. 3% had Medicaid or Medicare insurance coverage or both. The clinic encounter time was 24 +/- 7.9 minutes (mean +/- SD), comparable to that for all telemedicine clinic encounters during the same period.

CONCLUSIONS

The adult sickle cell population in rural Georgia accepts innovative health care delivery using telemedicine. Thus, the telemedicine sickle cell clinic has increased access to care for rural patients in underserved areas. For providers, it has allowed greater clinical productivity and diminished travel time to outreach clinics.

Ganciclovir chemoablation of herpes thymidine kinase suicide gene-modified tumors produces tumor necrosis and induces systemic immune responses

The goal of this work was to identify potential host immune responses to thymidine kinase (TK) suicide gene-modified tumors undergoing chemoablation induced by the prodrug ganciclovir (GCV). The aims were to measure the efficacy and specificity of immunity induced against unmodified tumor, to identify qualitative or quantitative changes in the host response to TK+ tumors undergoing chemoablation that may contribute to the induction of antitumor immunity, and to compare critically the induction of immunity by chemoablation of TK-modified tumors with that of other methods of immunization in this tumor model and in response to other well-defined model antigens. Animals treated with TK+ tumors and GCV developed specific resistance to rechallenge with unmodified tumor. GCV induced significant tumor necrosis, which was associated with a pronounced host cell infiltrate composed of polymorphonuclear cells, both CD4+ and CD8+ T lymphocytes, and increased intratumoral IL-12. Cyclophosphamide-treated mice exhibited no such host response despite the induction of tumor necrosis. CTL responses to defined antigens in TK+ cells were greater in animals treated with prodrug than were those in animals not treated with prodrug but harboring live TK+ cells. Similar degrees of immunity were produced by immunization with irradiated cells.

CENP-G: a new centromeric protein that is associated with the alpha-1 satellite DNA subfamily

A new constitutive centromere-specific protein (CENP) has been identified as a result of its recognition as an autoantigen by serum from a patient with gastric antral vascular ectasia disease. Conventional immunoblotting and two-dimensional double blotting with both this antiserum and a known anti-centromere antiserum showed that this antiserum predominantly recognized a Mr 95,000 protein that is different from all known CENPs. We have named this new protein CENP-G. This protein was detected at the centromeric region throughout the cell cycle. In mitosis, it was restricted to the kinetochore inner plate as shown by immunogold labeling and electron microscopy. The centromeres of some human chromosomes are known to contain two subfamilies of alpha-satellite DNA. Using immunofluorescence combined with fluorescent in situ hybridization with subfamily-specific DNA probes, we revealed that CENP-G was specifically associated with one of the subfamilies, which we have named alpha-1, but not the other. The localization and the alpha-1-specific association suggested that CENP-G may play a role in kinetochore organization and function. Like CENP-B and C, but unlike CENP-A, this protein remained with the nuclear matrix after intensive extraction. While CENP-B is absent from the human Y chromosome, the existence of CENP-G on the Y chromosome has been proven by immunofluorescence and whole chromosome painting. CENP-G was also detected in CHO, Indian muntjac and Chinese muntjac cells, suggesting that it is conserved in evolution.

Jarman underprivileged area scores, tooth decay and the effect of water fluoridation

OBJECTIVE

To examine the association between dental caries and Jarman underprivileged area scores at regional, district and electoral ward level and explore any possible relationship with water fluoridation.

DESIGN

An ecological study using the English results from the NHS dental surveys on 5-year-old children in 1991/2 and 1993/4, and the survey of 12-year-old children in 1992/3. Jarman underprivileged area scores were used from the 1991 census.

SETTING

The study used former English health authority regions and districts. The electoral wards were in non-fluoridated Salford and Trafford and Liverpool, and fluoridated Newcastle and North Tyneside.

SUBJECTS

The random sample of 5-year-old children examined in 1991/2 and 1993/4, and 12-year-old children in 1992/3, in studies coordinated by the British Association for the Study of Community Dentistry.

OUTCOME MEASURES

Correlations between regional, district and electoral ward mean dmft/DMFT and Jarman underprivileged area scores.

RESULTS

Significant correlations were demonstrated at a regional level in 5-year-old children in 1991/2, district level in 5-year-old children in 1991/2 and 1993/4 and at electoral ward level in both age groups in 1992/3 and 1993/4. Correlation coefficients varied between r = 0.88 to r = 0.46. Multiple linear regression at electoral ward level showed significant interactions between Jarman scores and water fluoridation. There was an average 44 per cent and 43 per cent reduction in caries in fluoridated electoral wards in 5- and 12-year-old children respectively. In deprived electoral wards, with a Jarman score of 40, the reduction in caries increased to 54 per cent and 56 per cent for 5- and 12-year-old children respectively.

CONCLUSIONS

Dental caries was associated with Jarman underprivileged area scores. The differential efficacy of fluoridation to deprived areas was demonstrated at electoral ward level. Water fluoridation was confirmed as an evidence based intervention which has halved the amount of tooth decay in 5- and 12-year-old children.

Emergency department use of flumazenil prior to poison center consultation

We studied the frequency of use of flumazenil by emergency departments in our region and compared it to recommendations made by specialists in poison information at our poison control center. For a 5-mo period, we prospectively collected cases involving benzodiazepines or zolpidem. Data was documented only from calls from emergency departments. Emergency department personnel were asked the following: If given, the dose and frequency, contraindications, and adverse reactions. Each case was followed to completion. Flumazenil was not given in 55 cases. Of the remaining 14 cases in which it was given, 10 of the cases received flumazenil prior to poison control center consultation. We noted 1 case of dizziness. Ten cases given flumazenil had contraindications (eg ethanol abuse or possible seizurogenic coingestants). Despite possible contraindications, flumazenil was given 10/14 times (71%) prior to calling the poison control center. These results point to potential overuse of this antidote where contraindications or cautions are suspected in the overdosed patients. Our study suggests that when flumazenil use is contemplated by an emergency department physician, a poison control center consult may have a contrary recommendation.

Generating ROC curves for artificial neural networks

Receiver operating characteristic (ROC) analysis is an established method of measuring diagnostic performance in medical imaging studies. Traditionally, artificial neural networks (ANN's) have been applied as a classifier to find one "best" detection rate. Recently researchers have begun to report ROC curve results for ANN classifiers. The current standard method of generating ROC curves for an ANN is to vary the output node threshold for classification. In this work, we propose a different technique for generating ROC curves for a two-class ANN classifier. We show that this new technique generates better ROC curves in the sense of having greater area under the ROC curve (AUC), and in the sense of being composed of a better distribution of operating points.

Social deprivation and tooth decay in Scottish schoolchildren

OBJECTIVES

To quantify the association between dental decay in Scottish Schoolchildren & social deprivation as measured by the Carstairs Index from the 1991 census.

DESIGN

An ecological study using data from the Scottish Health Boards Dental Epidemiology Programme and The Public Health Common Data set.

SETTING

Scottish Health Boards from 1992-3 to 1994-5.

SUBJECTS

Random samples of 5,920 five-year-olds, 5,344 12-year-olds and 6,007 14-year-olds across the 15 Health Boards in Scotland.

RESULTS

Positive correlations were demonstrated in all age groups; 12-year-olds (r = 0.72) in 1992-3, 5-year-olds (r = 0.8) in 1993-4 and 14-year-olds (r = 0.55) in 1994-5. Dental decay in all age groups was positively and significantly associated with deprivation as measured by the Carstairs index.

CONCLUSION

Tooth decay was confirmed as a disease associated with social deprivation in Scotland. The increasing polarisation of decay to socio-economically deprived groups of the population, suggests a 'whole population' approach such as water fluoridation would prevent tooth decay in these deprived groups most effectively. Nevertheless all evidence-based interventions should be used to try to narrow the "Dental Health Divide' by improving the dental health of deprived individuals.

Hospital utilization patterns and costs for adult sickle cell patients in Illinois

OBJECTIVES

To determine population size, demographic characteristics, hospital utilization patterns, the specialties of physicians providing care, and costs for hospitalized adult sickle cell patients in Illinois.

METHODS

A statewide, administrative dataset for the two-year period from january 1992 through December 1993 was analyzed retrospectively.

RESULTS

There were 8403 admissions among 1189 individual sickle cell patients for the two-year period. Eighty-five percent of patients resided in the Chicago metropolitan area. The median age of the 1189 patients was 29; two-thirds had Medicaid or Medicare coverage. Emergency departments were the primary source of admissions (85.7%). The most common admitting diagnosis was painful crisis (97.4%), and average length of stay was four days. The median number of admissions per patient was three; most patients (85%) used only one or two hospitals. A small group used more than four hospitals and accounted for 23% of statewide admissions. Primary care physicians cared for most patients, and total hospitalization charges were more than $59 million.

CONCLUSIONS

In Illinois the adult sickle cell population is concentrated in major urban centers, primarily the Chicago metropolitan area. These patients accounted for approximately 8400 admissions and more than $59 million in hospital charges during the two-year study period. A small group of patients used multiple hospitals and accounted for more than 23% of total hospitalization charges. This study shows the necessity of and provides a useful framework for developing targeted programs for adult sickle cell patients as well as for training physicians to efficiently provide comprehensive health care services for this population.

Index of Orthodontic Treatment Need, its use in a dental epidemiology survey calibration exercise

The Index of Orthodontic Treatment Need (IOTN) was included in a pre-survey calibration exercise of 18 dental epidemiologists. Nine months later 16 of the epidemiologists were re-calibrated in the IOTN. The Index was readily accepted by the experienced dental epidemiological examiners and each examination was estimated to be extended by, on average, less than two minutes. The inter-examiner agreement of the dental health component using the weighted kappa statistic improved from a mean of 0.53 (moderate agreement) for the first calibration to 0.66 (good agreement) at the second calibration. The mean inter-examiner agreement on the aesthetic component using the weighted kappa statistic reduced from 0.52 for the first calibration to 0.49 at the second. Using sensitivity and specificity to measure agreement on the dichotomous decision of those defined as having a definite treatment need, mean sensitivity rose from 0.72 to 0.79 and specificity from 0.90 to 0.97. It is concluded that dental examiners for epidemiological surveys can be trained to use the IOTN by using a pre-calibration exercise and that agreement on the dental health component improves after the index has been used for some months.

A nucleolar RNA helicase recognized by autoimmune antibodies from a patient with watermelon stomach disease

Watermelon stomach is characterized by prominent stripes of ectatic vascular tissue in the stomach similar to stripes on a watermelon; in patients with this disorder chronic gastrointestinal bleeding occurs and approximately half of these patients have associated autoimmune disorders. In the serum of one patient, an antinucleolar antibody titer of 1:25 600 was found; the antibodies specifically recognized an approximately 100 kDa nucleolar protein, which we referred to as the 'Gu' protein. Its cDNA was cloned and sequenced. The Gu protein is a member of a new subgroup of RNA helicases, the DEXD box family. Gu protein fused with glutathione S-transferase contains ATP-dependent RNA helicase activity which preferably translocates in the 5'-->3' direction. Its RNA folding activity, RNA-dependent ATPase and dATPase activities, and its translocation direction are similar to those of RNA helicase II [Flores-Rozas, H. and Hurwitz, J. (1993) J. Biol. Chem. 268, 21372-21383]. Sequencing of 209 amino acids of RNA helicase II peptides showed 96.7% identity with the cDNA-derived amino acid sequence of the Gu protein. The precise biological roles of this RNA helicase in the biogenesis of ribosomal RNA and the pathogenesis of watermelon disease and autoimmune disorder require further study.

Learning Membership Functions in a Function-Based Object Recognition System

Functionality-based recognition systems recognize objects at the category level by reasoning about how well the objects support the expected function. Such systems naturally associate a ``measure of goodness'' or ``membership value'' with a recognized object. This measure of goodness is the result of combining individual measures, or membership values, from potentially many primitive evaluations of different properties of the object's shape. A membership function is used to compute the membership value when evaluating a primitive of a particular physical property of an object. In previous versions of a recognition system known as Gruff, the membership function for each of the primitive evaluations was hand-crafted by the system designer. In this paper, we provide a learning component for the Gruff system, called Omlet, that automatically learns membership functions given a set of example objects labeled with their desired category measure. The learning algorithm is generally applicable to any problem in which low-level membership values are combined through an and-or tree structure to give a final overall membership value.

The insulin-like growth factor I generation test in the investigation of short stature

Genotypic and phenotypic heterogeneity in patients with growth hormone (GH) insensitivity syndrome suggests that partial defects exist in the GH receptor. The insulin-like growth factor I (IGF-I) generation test was assessed as a means of identifying partial GH receptor defects in a heterogeneous group of 22 prepubertal children with short stature. In a subgroup of nine patients with peak GH levels of 63.7 +/- 3.7 mU/l during a glucagon tolerance test, the response to the IGF-I generation test was no different from that for the group as a whole (peak GH, 43.3 +/- 4.5 mU/l), despite the fact that this subgroup exhibited a negative relationship between height SDS and peak GH and a positive relationship between height SDS and IGF binding protein-3. This preliminary study therefore suggests that the IGF-I generation test in its present form will not be useful as a primary screening test for partial GH insensitivity. Despite this, the IGF-I generation test has been extremely useful in the confirmation of the diagnosis of GHIS and may therefore also prove useful in the confirmation of partial defects in the GH receptor. A subgroup of short children with peak GH levels above 40 mU/l had some characteristics of partial GH receptor deficiency. These children, to whom GH therapy would not normally be given, may respond better to recombinant human IGF-I.

Stability of foscarnet sodium in 0.9% sodium chloride injection

The stability of foscarnet sodium in 0.9% sodium chloride injection was studied. Foscarnet sodium 24 mg/mL was added to polyvinyl chloride i.v. bags containing 0.9% sodium chloride injection to give a theoretical foscarnet sodium concentration of 12 mg/mL. Ten bags of solution were stored at 25 degrees C in normal laboratory light, 10 bags were stored at 25 degrees C in the dark, and 10 bags were stored at 5 degrees C in the dark. Samples were analyzed for foscarnet concentration by high-performance liquid chromatography on days 0, 3, 8, 10, 15, and 30. The solutions were visually inspected for particulates, and pH was measured. Foscarnet sodium was stable in all the solutions for up to 30 days under all the storage conditions; mean foscarnet concentrations did not decline below 99% of initial values. No particulates appeared, and there were no important changes in pH. Foscarnet sodium 12 mg/mL in 0.9% sodium chloride injection was stable for up to 30 days when stored at 25 degrees C and exposed to light, 25 degrees C and protected from light, or 5 degrees C and protected from light.

Image segmentation in digital mammography: comparison of local thresholding and region growing algorithms

Local thresholding and region-growing algorithms are developed and applied to digitized mammograms to quantify the parenchymal densities. The algorithms are first evaluated and optimized on phantom images reflecting varying image contrast, X-ray exposure conditions, and time-related changes. The difference between the segmentation results of the two techniques is less than 6% on the phantom images and 11% on the mammograms. The agreement between the computerized procedures and a manual one is in the range of 74-98%, depending on the breast parenchymal pattern and segmentation algorithm. The results show that computerized parenchymal classification of digitized mammograms is possible and independent of exposure.

Gelatinolytic metalloproteinase secretion patterns in ocular melanoma

Fifteen posterior uveal melanoma cell lines were analyzed qualitatively for gelatinolytic and caseinolytic proteinase activity after one to five in vitro passages. All 15 cell lines secreted a gelatinolytic metalloproteinase, with an apparent molecular weight of 72 kD, into protein-free culture media; nine of these secreted an additional gelatinolytic metalloproteinase with an apparent molecular weight of 92 kD. Neither species had the ability to degrade casein. This approach may provide insight into the mechanisms of tumor metastasis in uveal melanoma.

Genetic linkage of Werner's syndrome to five markers on chromosome 8

Werner's syndrome (WS) is a rare autosomal recessive disease in which the affected individuals display symptoms of premature ageing. The substantial phenotypic overlap between WS and normal ageing indicates that these two conditions may have pathogenetic mechanisms in common. The WS mutation has pleiotropic effects, and patients and their cells show many differences compared with normals. Despite extensive study of the clinical and biochemical features of this disorder, the primary genetic defect remains unknown. We have undertaken a genetic linkage study in an effort to identify the locus of the primary defect. Here we report close genetic linkage of the WS mutation to a group of markers on chromosome 8.

An investigation of parotid gland function and histopathology in autoimmune disease-prone mice of different age groups

This work aimed to characterize parotid gland function in autoimmune disease-prone murine strains (MRL/n, MRL/l and NZB/W) in relation to increasing age and to relate the extent of functional impairment to the intensity of histopathologic changes observed at the different ages. Pilocarpine-stimulated parotid saliva was collected to assess salivary flow rate and composition. Parotid tissue was then removed for histopathologic assessment. Parotid flow rates were not significantly reduced in autoimmune strains compared to controls but were reduced with age in NZB/W mice and in males of the C57 (control) strain. Age-related salivary compositional changes were present in MRL/l mice and in male NZB/W mice. Focal lymphocytic adenitis increased with age in prevalence and intensity in both sexes. The functional and histopathologic changes were not closely correlated. These results suggest that the parotid gland of autoimmune disease-prone mice provides only a poor replication of the salivary changes in human Sjögren's syndrome. Nevertheless, both the functional and histopathological changes developing in these strains, even though of limited extent, are significantly influenced by age.

Management of myocardial infarction in the elderly: admission and outcome on a coronary care unit

A data base of 1,511 patients admitted to a single Coronary Care Unit was analysed to examine the potential impact of thrombolytic therapy in elderly patients with myocardial infarction. Age was confirmed as a highly significant prognostic factor, and cost utility analysis showed that the cost of thrombolytic therapy with streptokinase in the elderly was lower per quality adjusted life year than in younger patients. However, median delay time of admission from onset of symptoms was significantly greater in this age-group, suggesting a need for a greater awareness of the benefits of thrombolytic therapy in elderly people.

Biochemical pharmacology of acyclic nucleotide analogues

Our studies have shown that the acyclic nucleotide analogues PMEA and HPMPC are able to penetrate into cells and are then activated to mono- and diphosphate derivatives. The latter correspond to triphosphate analogues and presumably serve an important role in the biological activity exerted by these antiviral agents. In support of this idea, the inhibitory effect of PMEApp on HIV reverse transcriptase has been demonstrated with both RNA and DNA template-primer systems. Further studies will be undertaken to determine the effect of HPMPCpp on viral DNA polymerases. Whereas the metabolism of PMEA in CEM cells gives rise to only PMEAp and PMEApp, additional metabolites were obtained in MRC-5 cells; the identity of these metabolites remains to be determined. In the case of HPMPC, a third metabolite was obtained in addition to HPMPCp and HPMPCpp, which has been tentatively assigned as a phosphate-choline adduct by analogy with activation of cytosine-based nucleoside derivatives. The metabolism of HPMPC was unchanged between uninfected and infected cells, indicating that viral enzymes are not necessary for the activation of HPMPC. The long intracellular half-lives of the HPMPC metabolites may have implications for the antiviral efficacy of this compound. The persistence of activated metabolites suggests that infrequent dosing may be possible due to a prolonged antiviral effect. Our results on the effectiveness of infrequent dosing schedules with HPMPC in the treatment of HSV 2 infections in mice support this hypothesis. It is also possible that HPMPCp-choline may serve as a reservoir for HPMPC and therefore for the presumed active metabolite HPMPCpp.

The effects of a liquid diet on initial and sustained, stimulated parotid salivary secretion and on parotid structure in the rat

Adult male rats were maintained on a nutritionally adequate liquid diet, or laboratory chow and water (controls), for 7 days. They were then anaesthetized and parotid flow was recorded after isoprenaline or pilocarpine stimulation, each collected over two, timed sampling periods--an initial 5 min and a subsequent 15 min. The isoprenaline-induced flow rates in liquid diet rats were reduced to 45 and 30% of those in control rats for the first and subsequent samples respectively (p less than 0.02). After pilocarpine stimulation there were no significant differences in the first samples, but in the subsequent samples the flow rate in liquid diet rats was reduced to 54% of that in controls (p less than 0.001). The parotid gland weights were reduced by 35% in liquid diet rats compared to controls (p less than 0.05). On computerized planimetric analysis, parotids (from rats that had not been given secretagogues) had significantly smaller mean acinar areas, mean acinar profile perimeters and mean acinar transection diameters after liquid feeding (p less than 0.001). The findings support the notion that there is a functional reserve capacity available in atrophied glands to support the relatively fast flow that occurs on initial stimulation but which becomes exhausted during sustained stimulation. This exhaustion occurs more severely and more rapidly in the low-volume, protein-rich saliva elicited by sympathomimetic stimulation than in the high-volume, low-protein saliva formed in response to parasympathomimetic stimulation.

Effects of acute ethanol administration on stimulated parotid secretion in the rat

Young adult male rats previously never exposed to ethanol were given a single dose of 4 ml of 35% (v/v) ethanol in water by direct intragastric intubation (approximate weight related dose = 5.2 g/kg). Control rats were given distilled water in the same volume by the same route or were given no intragastric fluids. After administration of Valium-Hypnorm anesthesia, parotid salivary secretion was stimulated by subcutaneous pilocarpine HCI (10 mg/kg), and accurately timed samples were collected. No differences were recorded in the rate of salivary flow during the initial (5-min) high-flow phase of secretion, but during the subsequent 25-min phase of secretion the output in ethanol-treated rats was depressed by 60% compared to controls (p less than 0.01). Furthermore, electrolyte analyses of this saliva indicated that salivary ductal resorptive activity might be diminished in the presence of high blood ethanol. However, when rats were previously habitually exposed to ethanol at a twice daily dose of 4 ml of 35% (v/v) ethanol in water, the inhibitory action of acute ethanol administration was abolished. Moreover, in these rats there was significantly depressed [Na+] in both high-flow and low-flow saliva samples (p less than 0.01) with little change in [Na+] occurring at higher flow rates. This suggests the possibility of enhanced ductal resorption developing in rats exposed to long-term ethanol feeding.

Chloride handling by submandibular cells from young and old rats with and without duct ligation

To examine the relation between structure and function in aging salivary glands, we have studied the duct-ligated submandibular gland of rats. Following 5-8 days ligation, glands from young (7-8 months) and old (21-23 months) rats exhibited approximately 90% loss in proportional volume of acinar cells. Most remaining epithelium was highly abnormal. No significant differences were detected in the ability of cells prepared from young and old animals, either control or ligated, to flux 36Cl-. Both basal uptake and muscarinic-cholinergic stimulated release were comparable.

The human astrocytoma cell line 1321 N1 contains M2-glandular type muscarinic receptors linked to phosphoinositide turnover

1. Muscarinic receptors present in the human astrocytoma cell line 1321 N1 were characterized in radioligand binding studies and in functional studies of carbachol-stimulated phosphatidylinositol (PI) turnover. 2. In radioligand binding studies the muscarinic receptor in intact cells could be labelled using [3H]-N-methylscopolamine ([3H]-NMS) but not by [3H]-pirenzepine. In the intact cells these receptors displayed low pirenzepine affinity (pKi = 6.83) indicating that they were not of the M1 subtype. Furthermore, the 1321 N1 muscarinic receptors displayed low affinity for the two M2-cardiac selective ligands methoctramine (pKi = 5.82) and AF-DX 116 (pKi = 6.29). This pharmacology was consistent with the 1321 N1 cells containing a single population of muscarinic receptors that displayed a similar pharmacology to the M2-receptor present in exocrine gland tissue. 3. The M2-gland nature of the receptors was further indicated in the functional studies where antagonist affinities were determined from their ability to antagonize carbachol-stimulated PI turnover in 1321 N1 cells. pA2 values for pirenzepine (7.31), methoctramine (6.10) and AF-DX 116 (6.52) were similar to those determined in the binding studies. 4. From these studies we conclude that 1321 N1 astrocytoma cells contain an M2-gland muscarinic receptor which mediates muscarinic receptor-mediated stimulation of PI turnover in these cells.

Salivary flow rate, protein and electrolyte concentrations in chronic alcoholic patients

Stimulated and unstimulated parotid salivas were examined in a series of non-cirrhotic patients under treatment for alcohol dependence and in age-sex matched, non-alcoholic, healthy, control subjects. Resting salivary flow was raised threefold in the alcohol group and the protein and electrolyte concentrations were also altered in this saliva. However, there were no intergroup differences in parotid flow or composition following gustatory stimulation by 6% citric acid. The results contrast with the wide parotid functional changes known to occur in stimulated parotid saliva in alcoholic cirrhosis and suggest, therefore, that the direct salivary effects of chronic alcohol abuse may be less important than the damaged liver function in contributing to the salivary disturbance reportedly occurring in alcoholic cirrhosis.