A homologue of Drosophila aurora kinase is oncogenic and amplified in human colorectal cancers

Genetic and biochemical studies in lower eukaryotes have identified several proteins that ensure accurate segregation of chromosomes. These include the Drosophila aurora and yeast Ipl1 kinases that are required for centrosome maturation and chromosome segregation. We have identified two human homologues of these genes, termed aurora1 and aurora2, that encode cell-cycle-regulated serine/threonine kinases. Here we demonstrate that the aurora2 gene maps to chromosome 20q13, a region amplified in a variety of human cancers, including a significant number of colorectal malignancies. We propose that aurora2 may be a target of this amplicon since its DNA is amplified and its RNA overexpressed, in more than 50% of primary colorectal cancers. Furthermore, overexpression of aurora2 transforms rodent fibroblasts. These observations implicate aurora2 as a potential oncogene in many colon, breast and other solid tumors, and identify centrosome-associated proteins as novel targets for cancer therapy.

Quantification of Ca2+-activated K+ channels under hormonal control in pig pancreas acinar cells

Ca2+- and voltage-activated K+ channels are found in many electrically excitable cells and have an important role in regulating electrical activity. Recently, the large K+ channel has been found in the baso-lateral plasma membranes of salivary gland acinar cells, where it may be important in the regulation of salt transport. Using patch-clamp methods to record single-channel currents from excised fragments of baso-lateral acinar cell membranes in combination with current recordings from isolated single acinar cells and two- and three-cell clusters, we have now for the first time characterized the K+ channels quantitatively. In pig pancreatic acini there are 25-60 K+ channels per cell with a maximal single channel conductance of about 200 pS. We have quantified the relationship between internal ionized Ca2+ concentration [( Ca2+]i) membrane potential and open-state probability (p) of the K+ channel. By comparing curves obtained from excised patches relating membrane potential to p, at different levels of [Ca2+]i, with similar curves obtained from intact cells, [Ca2+]i in resting acinar cells was found to be between 10(-8) and 10(-7) M. In microelectrode experiments acetylcholine (ACh), gastrin-cholecystokinin (CCK) as well as bombesin peptides evoked Ca2+-dependent opening of the K+ conductance pathway, resulting in membrane hyperpolarization. The large K+ channel, which is under strict dual control by internal Ca2+ and voltage, may provide a crucial link between hormone-evoked increase in internal Ca2+ concentration and the resulting NaCl-rich fluid secretion.

Risk factors for syncope recurrence after a positive tilt-table test in patients with syncope

BACKGROUND

Recent work with head-up tilt-table testing has suggested that many patients with syncope may have recurrent neurally mediated episodes of bradycardia, hypotension, or both. The purpose of this study was to determine how to identify patients at high risk of a recurrence of neuromediated syncope after a positive isoproterenol/tilt-table test.

METHODS AND RESULTS

A cohort of 101 drug-free patients in a university hospital outpatient clinic with syncope and a positive isoproterenol/tilt-table test underwent baseline assessment of demographic variables, symptomatic burden, and hemodynamic and clinical responses to tilt testing. The primary outcome measure was the time to the first recurrent syncopal spell. The actuarial probabilities of remaining syncope free after 1 and 2 years were 72% and 60%, respectively. Multivariate proportional hazards analysis demonstrated that the most powerful predictor of a recurrence of syncope was the logarithm of the number of preceding syncopal spells (P<.001). Other predictive variables included the duration of syncopal symptoms, tilt test symptomatic outcome, and trough heart rate. The probability of a recurrence of syncope also varied with the logarithm of the frequency of preceding spells (P=.008). The median frequency of pretest spells was 0.3/month; after the tilt test, the median frequency dropped approximately 90% to 0.03 per month.

CONCLUSIONS

The risk of a recurrence of syncope after a positive tilt-table test can be predicted with simple pretest and intratest variables.

Possible association between fluoxetine hydrochloride and colic in an infant

This is a case study of a 6-week-old infant referred for colic whose mother was using fluoxetine hydrochloride and breast feeding the infant. The mother switched to a commercial formula and reported a dramatic decrease in the infant's crying. We asked the mother to feed the infant breast milk from a bottle and she agreed. Throughout the study the mother kept a daily diary of her infant's crying, sleeping, stooling patterns, and feeding problems. Analysis of the mother's breast milk showed concentrations of 69 ng/mL for fluoxetine and 90 ng/mL for norfluoxetine. Infant blood serum/plasma level was analyzed for fluoxetine hydrochloride following return to breast milk. The concentrations were 340 ng/mL for fluoxetine and 208 ng/mL for norfluoxetine. The diary records showed increased crying, decreased sleep, increased vomiting, and watery stools when fluoxetine hydrochloride was transmitted through breast feeding or breast milk in bottle. These symptoms were reduced when the infant was formula fed. We suggest a possible relationship between colic and associated symptoms and fluoxetine hydrochloride in maternal breast milk.

Effect of beta blockers on the time to first syncope recurrence in patients after a positive isoproterenol tilt table test

Isoproterenol-headup tilt table testing provides a diagnosis of neuromediated syncope in many patients who faint. The involvement of beta-adrenoceptor stimulation in the provocation of syncope suggests that beta blockers might chronically prevent syncope. To assess this, a cohort of 153 syncope patients (age 39 +/- 20 years) underwent baseline assessment of demographic variables, symptomatic burden, and hemodynamic and clinical responses to tilt testing. Fifty-two patients then received beta blockers, and 101 did not receive drug therapy. The primary outcome was the time to the first recurrent syncopal spell. Actuarial survival analysis was used. Syncope recurred in 17 of 52 patients who received beta blockers and in 28 of 101 patients who were untreated. The actuarial probability of remaining free of syncope was similar in both groups. For example, the probability of remaining free of syncope 12 months following the tilt test was 0.72 in both populations. Thus, treatment with beta blockers may not have a significant effect in preventing syncope recurrence following a positive tilt test.

Effects of intraventricular hemorrhage and socioeconomic status on perceptual, cognitive, and neurologic status of low birth weight infants at 5 years of age

A prospective longitudinal study assessed the effects of intraventricular hemorrhage (IVH) and socioeconomic status on the perceptual, cognitive, and neurologic status of preterm infants at 5 years of age. The preterm group consisted of infants with no IVH, grade I to II IVH, and grade III to IV IVH; a control group of normal term infants was also studied. Outcome was evaluated at 3, 4, and 5 years of age. Twenty-four percent of infants with grade III to IV IVH had abnormal neurologic diagnoses at 5 years of age. Correlations of predictor variables including IVH status, latency of visual evoked response, days of hospitalization, and socioeconomic status with 5-year neurologic outcome indicated that IVH status and visual evoked response at 1, 2, and 3 years continued to have an effect on neurologic outcome, but socioeconomic status and days of hospitalization did not; socioeconomic status did have a significant effect on the McCarthy cognitive scores but not on the perceptual scores at 5 years. Multiple regression analyses revealed that duration of hospitalization (reflecting neonatal morbidity), visual evoked response, and socioeconomic status all have independent effects on the cognitive index, whereas only duration of hospitalization has an independent effect on the perceptual index. These data support the concept that a complex interaction of biologic and environmental risk factors determines the degree of recovery from IVH by high-risk preterm infants.

Comparison of biphasic and monophasic shocks for defibrillation using a nonthoracotomy system

A comparison of defibrillation thresholds was made using biphasic and monophasic shocks delivered by a nonthoracotomy lead system in 2 clinically distinct groups of patients. The first group were patients receiving an implantable cardioverter-defibrillator who were studied before surgery with their chests closed. The second group were patients undergoing coronary artery bypass grafting (CABG) who were studied before surgery with their chests open but reapproximated. Biphasic defibrillation thresholds (stored energy) were significantly (p < 0.001) less than monophasic ones in subjects with the implantable cardioverter-defibrillator (12.3 +/- 5.3 vs 21.1 +/- 9.3 J) or CABG (14.6 +/- 7.1 vs 24.2 +/- 12.6 J). These values are less than were previously reported with a similar nonthoracotomy lead configuration. There were no significant differences between the 2 groups in all measurements derived from corresponding shock waveforms, although impedance tended to be greater in patients with CABG. However, subjects with CABG had greater left ventricular ejection fractions and did not have history of potentially lethal ventricular arrhythmias. Despite these differences, the conclusion that biphasic shocks are more effective would have been made in a study of either group alone. It is concluded that patients with CABG who have not had preceding potentially lethal ventricular arrhythmias may be a potential source of surrogate subjects for defibrillation research such as epicardial mapping, which requires that the chest be open.

Spontaneous changes of unilateral nasal airflow in man. A re-examination of the 'nasal cycle'

It is now over 100 years since Kayser (Archiv für Laryngol Rhinol 1895; 3: 101-120) first reported in the scientific literature that the human nasal passages exhibit spontaneous changes in unilateral nasal airway resistance, yet our understanding of this unusual phenomenon is still very confused. Spontaneous, reciprocal changes in unilateral nasal resistance are often referred to as a "nasal cycle" and although this term is now commonly used to describe spontaneous changes in nasal resistance in man and animals, there is little evidence for any true periodicity. A major problem in increasing our knowledge and understanding of the so-called "nasal cycle" is that most studies have relied on simple descriptions of the changes in nasal resistance and have not developed any numerical parameters to quantify the changes in resistance over time. This lack of definition of what actually constitutes a nasal cycle has meant that the literature of the present day generally accepts the views put forward by Heetderks (Am J Med Sci 1927; 174; 231-244) and Stoksted (Acta Otolaryngol (Stockh) 1953; Suppl 109: 159-175) that around 80% of the healthy population exhibit a regular cycle. In order to define the characteristics of the spontaneous changes in nasal airway resistance we have used numerical measures of reciprocity and also developed a measurement of the division of airflow between the nasal passages over time. With these two parameters it is possible to describe the nature of the spontaneous changes in airflow in numerical terms and to define what exactly constitutes a nasal cycle. Fifty-two volunteers underwent hourly measurement of unilateral nasal airflow for 8 h. For each volunteer, two values were derived from the graph of unilateral nasal airflows against time; the correlation coefficient between unilateral airflows (r) and the airflow distribution ratio between the two nasal airways (ADR). The spread of different types of airflow pattern (nasal cycle) throughout the population was illustrated by plotting r against ADR for each subject. A nasal cycle was defined as having an r value between -0.6 and -1.0, and an ADR value between 0.7 and 1.0. Only 21% (11 of the 52 volunteers) exhibited airflow patterns that could be defined as a nasal cycle in these terms. This finding contradicts the generally accepted, but undefined, view that around 80% of the population exhibit a regular nasal cycle. The numerical definition of a nasal cycle in terms of both reciprocity and airflow distribution, as described in this paper may help to clarify our understanding of this interesting phenomenon and allow rhinologists to describe the spontaneous changes in nasal airflow in more exact terms than have been used previously in the literature.

Independent orientation-selective mechanisms for the cardinal directions of colour space

Simultaneous, oppositely tilted, aftereffects were obtained for pairs of equiluminant gratings (e.g. magenta/cyan vs purple/greenish-yellow) and pairs of equiluminant and luminant gratings (e.g. magenta/cyan vs dark-grey/light-grey, or purple/greenish-yellow vs dark-grey/light-grey). Maximum aftereffects occurred for gratings whose colours were modulated along the principle axes of the colour space of Krauskopf, Williams and Heeley (1982): an axis of short-wavelength cone activation (B-cone axis), the difference between long- and medium-wavelength cone activation (R-G cone axis), and an axis of a contrast ratio of long-, medium- and short-wavelength cone activation (R + G + B cone axis). The results indicate that selectivity for orientation occurs independently in at least two chromatic channels and one achromatic channel.

Antibiotic resistant tuberculosis in the United Kingdom: 1993-1999

BACKGROUND

The re-emergence of tuberculosis as a global health problem over the past two decades, accompanied by an increase in tuberculosis drug resistance, prompted the development of a comprehensive national surveillance system for tuberculosis drug resistance in 1993.

METHODS

The UK Mycobacterial Resistance Network (Mycobnet), which includes all mycobacterial reference and regional laboratories in the UK, collects a minimum dataset on all individuals from whom an initial isolate of Mycobacterium tuberculosis complex has been isolated and submitted by source hospital laboratories. Data sought include susceptibility to first line antibiotics, demographic, geographical, and risk factor information.

RESULTS

There were 25 217 reports of initial isolates of M tuberculosis complex in the UK between 1993 and 1999. All were tested for sensitivity to isoniazid, rifampicin, and ethambutol and 12 692 of the isolates were also tested for sensitivity to pyrazinamide and streptomycin. A total of 1523 (6.1%) isolates were resistant to one or more drugs, 1397 isolates (5.6%) were resistant to isoniazid with or without resistance to other drugs, and 299 (1.2%) were multidrug resistant. Although the numbers of drug resistant isolates increased over the period, the proportions remained little changed. Certain groups of people were at a higher risk of acquiring drug resistant tuberculosis including younger men, residents of London, foreign born subjects, patients with a previous history of tuberculosis and those infected with HIV.

CONCLUSION

Although the proportion of drug resistant tuberculosis cases appears to be stable in the UK at present, more than one in 20 patients has drug resistant disease at diagnosis and more than one in 100 has multidrug resistant disease. Tuberculosis control measures should be strengthened to minimise the emergence of drug resistance through rapid diagnosis, rapid identification of drug resistance, supervised treatment, and maintenance of comprehensive surveillance.

Quantitative assessment by flow cytometry of T-lymphocytes producing antigen-specific gamma-interferon in Brucella immune cattle

Peripheral blood mononuclear cells (PBMC) isolated from cattle infected with Brucella secreted gamma-interferon (IFN-gamma) after antigen-specific stimulation with Brucellergene, which is a mixture of cytoplasmic proteins of rough Brucella melitensis B115. Following the depletion of the monocyte-macrophages from the PBMC, the enriched lymphocyte populations stimulated with Brucellergene did not produce IFN-gamma. Two-colour immunofluorescence staining of intracellular IFN-gamma and bovine cell surface molecules identified the cells producing IFN-gamma among the PBMC stimulated with Brucellergene. Moreover, this method could be used to estimate the number of T-cells specifically producing IFN-gamma. For a given animal, there is a significant correlation (p < 0.05) between the production of IFN measured by an ELISA of the supernatant of whole blood stimulated with Brucellergene and the number of T-cells producing IFN-gamma after in vitro stimulation with Brucellergene. The development of the immunofluorescence staining technique provides a new tool for analysing and for measuring the T-cell immune response in cattle.

Inhibition of iron absorption by omeprazole in rat model

Since gastric acid is an important luminal factor in the absorption of non-heme iron, the effect of omeprazole on the absorption of iron in a rat model was studied. Iron absorption studies were performed on rats on a normal diet (N = 42) and rats fed an iron-deficient diet (N = 43) for three weeks. Rats were orally dosed with 40 mumol/kg of omeprazole or placebo daily for two days prior to iron absorption studies. Rats were orally dosed with 1 mmol of ferrous chloride, ferric chloride or food iron (dietary suspension) containing 11 micrograms of iron and labeled with 1 microCi of 59Fe. Omeprazole-treated rats on the normal diet had no significant reduction in the absorption of ferric, ferrous, or food iron. In the rats on the iron-deficient diet, the absorption of ferrous iron decreased from 76 +/- 7.5% (mean +/- SE) in control rats to 38 +/- 8.5% in the omeprazole-treated rats (P less than 0.003) and the absorption of food iron decreased from 65 +/- 7.5% in control rats to 37 +/- 6.5% in the omeprazole-treated rats (P less than 0.016). There was no significant reduction in the absorption of ferric iron. Omeprazole therapy is unlikely to be associated with significant iron malabsorption in normal patients but may reduce iron absorption in pathological states associated with increased iron absorption such as iron deficiency.

Diagnosis of bovine brucellosis by skin test: conditions for the test and evaluation of its performance

Brucellergene OCB (Rhône-Mérieux) was used as an allergen to define the intrinsic parameters of a skin test and to compare its properties with serology for the diagnosis of bovine brucellosis. The skin test was also evaluated for its capacity to solve problems associated with false positive reactions in serological tests. The optimal reading delay for the skin test was 72 hours. The brucellosis allergic reaction was two to three times less intense than the tuberculosis allergic reaction. An increase of 1.1 mm or more in the skin thickness was therefore considered to be an adequate cut-off. The specificity calculated for 1192 brucellosis-free animals (including animals from brucellosis-free herds in which false positive serological reactions had been reported) was 99-83 per cent (95 per cent confidence interval [CI] 99-40 to 99-98 per cent). The sensitivity determined from 27 experimentally infected heifers ranged from 93 per cent (95 per cent CI 76 to 100 per cent) to 78 per cent (95 per cent CI 58 to 91 per cent) when measured respectively one and six months after the infection. Allergic reactions could be detected in vaccinated animals up to four-and-a-half years after the vaccination. On the other hand, no sensitisation was recorded in naïve animals after up to eight monthly injections of the allergen. The skin test gave valuable information, in combination with the serological tests, in both acute and chronic brucellosis. The skin test discriminated brucellosis clearly from false positive serological reactions due to infections with Yersinia enterocolitica O9.

Ultrio and Ultrio Plus non-discriminating reactives: false reactives or not?

BACKGROUND

The low, fluctuating levels of DNA characteristic of occult hepatitis B infection make its detection by nucleic acid testing (NAT) a challenge.

METHODS

Four year's routine use of the Ultrio and Ultrio Plus assays in blood donations in New Zealand was analysed.

RESULTS

0·09% of donations tested with Ultrio and Ultrio Plus assays showed reactivity in the multiplex assay, but non-reactivity in all three discriminatory assays and relevant mandatory serological assays (anti-HIV, anti-HCV, HBsAg). These donations were more likely to be anti-HBc reactive (Ultrio, 13%; Ultrio Plus, 57%; random donors, 6·8%). Thirty-four per cent of these anti-HBc-reactive donations were also reactive in either an alternate NAT assay or on repeat multiplex testing. Thirteen per cent of the donors of the discriminatory-negative, anti-HBc-reactive donations who had given other Ultrio- or Ultrio Plus-tested donations had at least one other multiplex reactive donation.

CONCLUSION

These findings suggest that their HBV DNA levels are around the assay's limit of detection, that false reactivity cannot be presumed when a donor fails to discriminate and that caution should be applied when deciding whether to continue accepting donations from such donors.

Predicting maltreatment of children of teenage mothers

OBJECTIVE

To determine the degree to which knowing certain characteristics about young high-risk families can help distinguish those families most likely to maltreat their children from those families at lower risk of maltreating their children.

DESIGN

Observational cohort from which the following predictor variables were gathered when infants were 2 months old: maternal age, depressive symptoms, childrearing attitudes, social support, and living situation (with or apart from related adults). Families were followed up for 24 months to identify the occurrence of maltreatment.

SETTING

An urban, socioeconomically disadvantaged cohort of teenage mothers and their infants attending a hospital-based special primary care clinic for teen mothers and their infants.

PARTICIPANTS

All full-term infants and mothers enrolled into the clinic in 1990 participated in the study. This included 47 mother-infant pairs enrolled when infants were 2 months of age. Forty-five of these pairs were available for follow-up when infants were 24 months of age.

MAIN OUTCOME MEASURES

Maltreatment defined as any incident that prompted investigation by the state child protective agency and was found to be a substantiated case of maltreatment by that agency.

RESULTS

Maltreatment occurred in 15 of 45 families before the child's second birthday. Discriminate function analysis produced a model that correctly classified 13 of 15 maltreating mothers and misclassified one of 30 non-maltreating mothers. Stepwise analysis revealed that living situation was by far the strongest predictive variable (R2 = 7).

CONCLUSION

Maltreatment was a predictable outcome within this extremely high-risk cohort. Living apart from related adults was the strongest risk factor associated with maltreatment. This easily obtainable piece of information may be an important risk marker for practitioners, social service personnel, and others working with this very-high-risk population. It may allow early supportive interventions that might prevent maltreatment.

Recombination by resolvase is inhibited by lac repressor simultaneously binding operators between res sites

The Tn3 resolvase requires that the two recombination (res) sites be aligned as direct repeats on the same molecule for efficient recombination to occur. To test whether resolvase must contact the DNA between res sites as predicted by tracking models, we have determined the sensitivity of recombination to protein diffusion blockades. Recombination between two res sites is unaffected either by lac repressor or bacteriophage T7 RNA polymerase being bound between them. Yet recombination is inhibited by lac repressor if the res site is bounded by a lac operator on both sides. We demonstrate that lac repressor will bind to more than one DNA site under the conditions used to assay recombination. This result suggests that lac repressor can inhibit resolvase by forming a DNA loop that isolates a res site topologically. These results do not support a tracking model for resolvase but suggest that the structure and topology of the DNA substrate is important in the formation of a synapse between res sites.

Disseminated Mycobacterium avium-intracellulare infection and red cell hypoplasia in patients with the acquired immune deficiency syndrome

During a period of 14 months in 1985 and 1986, infection with Mycobacterium avium-intracellulare (MAI) complex was diagnosed in 10 of 76 patients with Human Immunodeficiency Virus (HIV)-associated infection. In eight of the 10 patients, the infection was disseminated. All eight patients were anaemic. A bone marrow aspirate and/or trephine biopsy performed in six of them revealed evidence of red cell hypoplasia. MAI was cultured from all six samples of bone marrow. The strains of MAI isolated were resistant to conventional antituberculous drugs but were susceptible in vitro to ansamycin, ethionamide and cycloserine. None of the eight patients responded clinically to antituberculous therapy. The eight anaemic patients had pronounced constitutional symptoms. We suggest that severe anaemia and constitutional symptoms in patients with HIV-associated disease should prompt a search for evidence of disseminated MAI infection.

Immunization status of children enrolled in a hospital-based medicaid managed care practice: the importance of the timing of vaccine administration

OBJECTIVES

To evaluate the immunization status of children enrolled in a hospital-based Medicaid managed care practice and to assess the impact of the timing of vaccine administration on measured immunization rates.

DESIGN AND METHODS

The medical records of all children between the ages of 19 and 35 months who were continuously enrolled in the Medicaid managed care practice for the last 6 months of 1996 were reviewed. Immunization status was determined for the following vaccines: diphtheria-tetanus-pertussis/diphtheria-tetanus-acellular pertussis (4 doses); Haemophilus influenzae type b (3 doses); poliovirus (3 doses); hepatitis B (3 doses); measles-mumps-rubella (1 dose); and overall for the basic series. Two assessment methods were used to determine the immunization status of the study children: (1) a count of all documented vaccines ("count"); and (2) only including vaccines that met minimal age and spacing intervals based on American Academy of Pediatrics and CDC recommendations ("interval assessment").

RESULTS

With the count method vaccine-specific immunization rates ranged from 88 to 95%, with overall coverage of 80% for the basic series. With the interval assessment method vaccine-specific immunization rates ranged from 74 to 92%, with overall coverage of 53% for the basic series.

CONCLUSIONS

When all documented vaccines were included in the assessment, vaccine-specific immunization rates approached national goals, although overall coverage remained below 90% in this Medicaid managed care practice. The substantially lower immunization rates obtained by the interval assessment method demonstrate the importance of considering the issue of vaccine timing when interpreting immunization rates and the need for policies for revaccinating children who were immunized at less than recommended intervals. The results also have implications for provider education regarding the early administration of vaccines.

Cluster of cases of Mycobacterium chelonae bacteraemia

Mycobacterium chelonae was isolated from the blood of four immunosuppressed patients over a period of 10 weeks. Three patients had intravascular catheters in situ and the other had a biliary stent. All presented with recurrent fever despite treatment with broad-spectrum antibiotics. Blood cultures using standard bacteriological medium yielded a gram-positive bacillus from each patient. Ziehl-Neelsen staining of these cultures demonstrated a branching acid-fast bacillus that was subsequently identified as Mycobacterium chelonae in each case. The isolates were sensitive to clarithromycin and, although success of treatment with clarithromycin monotherapy has been variable, this antibiotic combined with removal of the intravascular catheters was used to treat those three patients. The treatment was successful with no recurrence of symptoms after 12 months of follow-up. The patient with the biliary stent died soon after Mycobacterium chelonae was isolated. Pyrolysis mass spectrometry analysis indicated the isolates were of two distinct strains. Radiological insertion of the Hickman lines and biliary stent was implicated epidemiologically as the source of infection.