Deletion of Tbc1d4/As160 abrogates cardiac glucose uptake and increases myocardial damage after ischemia/reperfusion

BACKGROUND

Type 2 Diabetes mellitus (T2DM) is a major risk factor for cardiovascular disease and associated with poor outcome after myocardial infarction (MI). In T2DM, cardiac metabolic flexibility, i.e. the switch between carbohydrates and lipids as energy source, is disturbed. The RabGTPase-activating protein TBC1D4 represents a crucial regulator of insulin-stimulated glucose uptake in skeletal muscle by controlling glucose transporter GLUT4 translocation. A human loss-of-function mutation in TBC1D4 is associated with impaired glycemic control and elevated T2DM risk. The study's aim was to investigate TBC1D4 function in cardiac substrate metabolism and adaptation to MI.

METHODS

Cardiac glucose metabolism of male Tbc1d4-deficient (D4KO) and wild type (WT) mice was characterized using in vivo [¹⁸F]-FDG PET imaging after glucose injection and ex vivo basal/insulin-stimulated [³H]-2-deoxyglucose uptake in left ventricular (LV) papillary muscle. Mice were subjected to cardiac ischemia/reperfusion (I/R). Heart structure and function were analyzed until 3 weeks post-MI using echocardiography, morphometric and ultrastructural analysis of heart sections, complemented by whole heart transcriptome and protein measurements.

RESULTS

Tbc1d4-knockout abolished insulin-stimulated glucose uptake in ex vivo LV papillary muscle and in vivo cardiac glucose uptake after glucose injection, accompanied by a marked reduction of GLUT4. Basal cardiac glucose uptake and GLUT1 abundance were not changed compared to WT controls. D4KO mice showed mild impairments in glycemia but normal cardiac function. However, after I/R D4KO mice showed progressively increased LV endsystolic volume and substantially increased infarction area compared to WT controls. Cardiac transcriptome analysis revealed upregulation of the unfolded protein response via ATF4/eIF2α in D4KO mice at baseline. Transmission electron microscopy revealed largely increased extracellular matrix (ECM) area, in line with decreased cardiac expression of matrix metalloproteinases of D4KO mice.

CONCLUSIONS

TBC1D4 is essential for insulin-stimulated cardiac glucose uptake and metabolic flexibility. Tbc1d4-deficiency results in elevated cardiac endoplasmic reticulum (ER)-stress response, increased deposition of ECM and aggravated cardiac damage following MI. Hence, impaired TBC1D4 signaling contributes to poor outcome after MI.

The paradox-breaking panRAF plus SRC family kinase inhibitor, CCT3833, is effective in mutant KRAS-driven cancers

BACKGROUND

KRAS is mutated in ∼90% of pancreatic ductal adenocarcinomas, ∼35% of colorectal cancers and ∼20% of non-small-cell lung cancers. There has been recent progress in targeting G12CKRAS specifically, but therapeutic options for other mutant forms of KRAS are limited, largely because the complexity of downstream signaling and feedback mechanisms mean that targeting individual pathway components is ineffective.

DESIGN

The protein kinases RAF and SRC are validated therapeutic targets in KRAS-mutant pancreatic ductal adenocarcinomas, colorectal cancers and non-small-cell lung cancers and we show that both must be inhibited to block growth of these cancers. We describe CCT3833, a new drug that inhibits both RAF and SRC, which may be effective in KRAS-mutant cancers.

RESULTS

We show that CCT3833 inhibits RAF and SRC in KRAS-mutant tumors in vitro and in vivo, and that it inhibits tumor growth at well-tolerated doses in mice. CCT3833 has been evaluated in a phase I clinical trial (NCT02437227) and we report here that it significantly prolongs progression-free survival of a patient with a G12VKRAS spindle cell sarcoma who did not respond to a multikinase inhibitor and therefore had limited treatment options.

CONCLUSIONS

New drug CCT3833 elicits significant preclinical therapeutic efficacy in KRAS-mutant colorectal, lung and pancreatic tumor xenografts, demonstrating a treatment option for several areas of unmet clinical need. Based on these preclinical data and the phase I clinical unconfirmed response in a patient with KRAS-mutant spindle cell sarcoma, CCT3833 requires further evaluation in patients with other KRAS-mutant cancers.

Identification of locally available structural material as co-substrate for organic waste composting in Tamil Nadu, India

Owing to the lack in structural strength while composting certain kinds of organic wastes, 11 co-substrates were tested that are generally locally available in rural areas of northern Tamil Nadu, India. In addition to the classical composting parameters such as carbon/nitrogen ratio, moisture content, dry matter and organic dry matter, a compression test was conducted to evaluate the structural strength and the suitability as bulking agent for composting processes. Additionally, with respect to the climatic conditions in India, the water holding capacity was also evaluated.

Whole-genome sequencing reveals complex mechanisms of intrinsic resistance to BRAF inhibition

BACKGROUND

BRAF is mutated in ∼42% of human melanomas (COSMIC. http://www.sanger.ac.uk/genetics/CGP/cosmic/) and pharmacological BRAF inhibitors such as vemurafenib and dabrafenib achieve dramatic responses in patients whose tumours harbour BRAF(V600) mutations. Objective responses occur in ∼50% of patients and disease stabilisation in a further ∼30%, but ∼20% of patients present primary or innate resistance and do not respond. Here, we investigated the underlying cause of treatment failure in a patient with BRAF mutant melanoma who presented primary resistance.

METHODS

We carried out whole-genome sequencing and single nucleotide polymorphism (SNP) array analysis of five metastatic tumours from the patient. We validated mechanisms of resistance in a cell line derived from the patient's tumour.

RESULTS

We observed that the majority of the single-nucleotide variants identified were shared across all tumour sites, but also saw site-specific copy-number alterations in discrete cell populations at different sites. We found that two ubiquitous mutations mediated resistance to BRAF inhibition in these tumours. A mutation in GNAQ sustained mitogen-activated protein kinase (MAPK) signalling, whereas a mutation in PTEN activated the PI3 K/AKT pathway. Inhibition of both pathways synergised to block the growth of the cells.

CONCLUSIONS

Our analyses show that the five metastases arose from a common progenitor and acquired additional alterations after disease dissemination. We demonstrate that a distinct combination of mutations mediated primary resistance to BRAF inhibition in this patient. These mutations were present in all five tumours and in a tumour sample taken before BRAF inhibitor treatment was administered. Inhibition of both pathways was required to block tumour cell growth, suggesting that combined targeting of these pathways could have been a valid therapeutic approach for this patient.

Objektivierung der Sehfunktionen bei Begutachtungen

For the determination of visual function an objective assessment is essential. Basic ophthalmologic examinations such as measurement of visual acuity and perimetry are dependent on patient statements. If the patient is not being able to provide adequate answers, as is the case for small children or mentally retarded patients, or also if the accuracy of the patient's statements is doubtful or simulation or aggravation is suspected, the denoted function in the evaluation of visual acuity has to be checked on consistency using different examination methods, and the results of objective functional tests, such as electrophysiology and morphological features, have to be taken into account.

Chorioretinopathia centralis serosa – Netzhautfunktion und -morphologie

BACKGROUND

The purpose of this study was to evaluate and compare retinal function and morphology in patients with central serous chorioretinopathy (CSC) using fundus perimetry and optical coherence tomography (OCT).

PATIENTS AND METHODS

In 14 eyes of 14 patients with unilateral and first manifestation of CSC, fundus perimetry with the Microperimeter 1 (MP1) as well as OCT were carried out. The average retinal thickness and the average differential light threshold of the corresponding visual field were analyzed.

RESULTS

All patients presented a serous detachment of the central neurosensory retina with a maximal retinal thickness of 381+/-82 microm. The microperimetric examination revealed on average a mean defect of 8.3+/-3.8 dB, which showed a good correlation to retinal thickness (r=0.73). Likewise, maximal retinal thickness and mean threshold values in the corresponding visual field displayed a good correlation (r=-0.58).

CONCLUSION

The MP1 enables quantification of functional defects in patients with CSC. Although visual acuity was only slightly reduced, all patients showed extensive scotomata in fundus perimetry, which correlated well with retinal thickness.

Statische Fundusperimetrie bei Probanden

BACKGROUND

The Microperimeter 1 (MP-1) allows for fundus-controlled static perimetry of the central visual field. The purpose of this study was to compare MP-1 fundus perimetry with the already established scanning laser ophthalmoscope (SLO) fundus perimetry concerning detected threshold values of light increment sensitivity in normals.

METHOD

In 31 eyes of 31 healthy volunteers a fundus controlled static threshold perimetry was carried out each with the MP-1 (Nidek Technologies) and the SLO (Rodenstock). In the central 21 degrees x 12 degrees visual field light increment sensitivity threshold values for 40 corresponding stimulus locations were compared in a rectangular 3 degree-grid.

RESULTS

The average light increment sensitivity was 19.1+/-0.5 dB with the MP-1 and 17.2+/-0.9 dB with the SLO. On average the threshold values of the 40 corresponding test locations were 1.9+/-1.3 dB higher with the MP-1 than with the SLO.

CONCLUSION

Both the MP-1 and SLO offer the possibility of a reproducible functional analysis of the central retina under simultaneous fundus control. For comparison of results of the MP-1 and SLO fundus perimetry, a correction factor of approximately 2 dB should be used.

Adult alpha-mannosidosis: clinical progression in the absence of demyelination

Alpha-mannosidosis is an inherited lysosomal storage disease. The authors report three siblings (ages 38 to 47 years) with the rare adult variant. All three had late-onset ataxia and retinal degeneration, adding to hearing loss, cognitive impairment, and dysotosis multiplex. One sibling also had psychosis. MRI revealed cerebellar atrophy and predominantly parieto-occipital white matter changes. MR spectroscopy showed no evidence for demyelination. It appears that the disabling course of adult alpha-mannosidosis is caused by lysosomal accumulation rather than demyelination.

Exhaled nitric oxide in the diagnosis of asthma: comparison with bronchial provocation tests

BACKGROUND

Bronchial provocation tests such as exercise, methacholine (MCH), and adenosine-5'-monophosphate (AMP) challenges are used extensively in the diagnosis of asthma. A study was undertaken to determine whether exhaled nitric oxide (eNO) can be used to diagnose asthma in patients with non-specific respiratory symptoms and to compare this test with conventional provocation tests.

METHODS

Patients with non-specific respiratory symptoms and normal spirometric parameters were included in the study. eNO was measured and exercise, MCH and AMP challenges performed in all subjects. Patients were defined as asthmatic based on clinical follow up 24 months after testing.

RESULTS

Forty patients were considered asthmatic and 45 were not. The area under receiver operating characteristic curves gave values of 0.896 for eNO, 0.781 for exercise, 0.924 for MCH, and 0.939 for AMP (p = 0.033, 0.575 and 0.085 for eNO v exercise, MCH and AMP respectively). From our data, a cut off value of NO > 7 ppb at a flow rate of 250 ml/s best differentiates between asthmatics and non-asthmatics (sensitivity 82.5%, specificity 88.9%). Optimal cut off values for other tests were exercise: deltaFEV1 > or = 10% (sensitivity 57.9%, specificity 100%); PC20-MCH: < or = 3 mg/ml (sensitivity 87.5%, specificity 86.7%); and PC20-AMP: < or = 150 mg/ml (sensitivity 89.5%, specificity 95.6%).

CONCLUSIONS

Measurement of eNO can be used as a safe, simple and rapid test for the diagnosis of asthma and is as good as bronchial provocation tests.

Tiefe Sklerektomie mit Hyaluronatimplantat vs. Trabekulektomie

BACKGROUND

It was investigated whether a very low target pressure could be achieved by modification of deep sclerectomy without losing the advantages of non penetrating surgery in comparison to conventional filtration surgery.

PATIENTS AND METHODS

A total of 22 eyes from 22 patients with advanced open angle glaucoma were randomly assigned to receive a deep sclerectomy or a trabeculectomy. Both groups received 0.02% mitomycin C under the conjunctiva prior to preparation of the scleral flap. In the deep sclerectomy group at least parts of the outer trabecular meshwork were removed until an apparent filtration was achieved. A dry cross-linked hyaluronate served as an implant. In the other group a classical trabeculectomy was performed.

RESULTS

The median intraocular pressure 12 months post-operation was 11.5 mm Hg in the deep sclerectomy group compared to 11 mm Hg in the trabeculectomy group; the median of the relative IOP reduction was -47% in the deep sclerectomy group, and -57% in the trabeculectomy group. The best corrected visual acuity was unchanged 12 months postoperatively in both groups.

DISCUSSION

As a more aggressive IOP-lowering procedure (intended filtration, use of antimetabolites) deep sclerectomy proved to be as effective as trabeculectomy. Nevertheless, the advantages of the more difficult surgical procedure concerning visual acuity, complications and surgical interventions were lost postoperatively.

What is the role of tests of lung function in the management of infants with lung disease?

This review considers whether there is a role for lung function tests in the clinical management of infants with lung disease. The purpose of testing lung function in older subjects, the tests available for infants, and the practical problems of testing lung function in infants are considered. After reviewing all the facts, we suggest that there are four situations in which lung function testing should be recommended for infants, as follows: (1) the infant who presents with unexplained tachypnea, hypoxia, cough, or respiratory distress in whom a definitive diagnosis is not apparent from physical examination and other, less difficult investigations; (2) the infant with severe, continuous, chronic obstructive lung disease who does not respond to an adequate clinical trial of combined corticosteroid and bronchodilator therapy; (3) the infant with known respiratory disease of uncertain severity in whom there is need to justify management decisions; and (4) research and development. A review of 62 recent publications to determine how lung function tests are being used at the present time showed that they are being used overwhelmingly for research. The role of lung function testing in the clinical management of infants has not been established, and research is needed to clarify this situation. We suggest that such studies should explore the role of lung function tests in infants with specific symptoms, signs, or diagnoses, taking into account information from other types of investigation and the cost/benefit/risk ratios.

Early diagnosis of primary ciliary dyskinesia in a newborn without situs inversus

Primary ciliary dyskinesia has been reported as a rare cause of respiratory distress during the neonatal period. This diagnosis is readily suspected in cases presenting with accompanying situs inversus. The aim of this study was to report on a pair of siblings with primary ciliary dyskinesia. The first case was an infant diagnosed with primary ciliary dyskinesia at the age of 14 d despite lack of situs inversus. The infant had presented with respiratory distress and atelectasis almost immediately after birth. The sibling, born one year later, presented with situs inversus, therefore allowing diagnosis of primary ciliary dyskinesia to be made immediately after birth.

CONCLUSIONS

Diagnosis of primary ciliary dyskinesia should be considered in newborns presenting with respiratory distress or atelectasis. Early institution of an adequate treatment programme and follow-up may reduce or prevent further complications of the disease.

A phase I trial of antibody directed enzyme prodrug therapy (ADEPT) in patients with advanced colorectal carcinoma or other CEA producing tumours

Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated selectively at the tumour site by an enzyme, which has been targeted to the tumour by an antibody (antibody-enzyme conjugate). Previous clinical trials have shown evidence of tumour response, however, the activated drug had a long half-life, which resulted in dose-limiting myelosuppression. Also, the targeting system, although giving high tumour to blood ratios of antibody-enzyme conjugate (10 000 : 1) required administration of a clearing antibody in addition to the antibody-enzyme conjugate. The purpose of this current study therefore was to attempt tumour targeting of the antibody-enzyme conjugate without the clearing antibody, and to investigate a new prodrug (bis-iodo phenol mustard, ZD2767P) whose activated form is highly potent and has a short half-life. Twenty-seven patients were treated with antibody-directed enzyme prodrug therapy using A5CP antibody-enzyme conjugate and ZD2767P prodrug, in a dose-escalating phase I trial. The maximum tolerated dose of ZD2767P was reached at 15.5 mg m(-2)x three administrations with a serum carboxypeptidase G2 level of 0.05 U ml(-1). Myelosuppression limited dose escalation. Other toxicities were mild. Patients' quality of life was not adversely affected during the trial as assessed by the measures used. There were no clinical or radiological responses seen in the study, but three patients had stable disease at day 56. Human anti-mouse antibody and human anti-carboxypeptidase G2 antibody were produced in response to the antibody enzyme conjugate (A5CP). The antibody-enzyme conjugate localisation data (carboxypeptidase G2 enzyme levels by HPLC on tumour and normal tissue samples, and gamma camera analysis of I-131 radiolabelled conjugate) are consistent with inadequate tumour localisation (median tumour: normal tissue ratios of antibody-enzyme conjugate of less than 1). A clearance system is therefore desirable with this antibody-enzyme conjugate or a more efficient targeting system is required. ZD2767P was shown to clear rapidly from the circulation and activated drug was not measurable in the blood. ZD2767P has potential for use in future antibody-directed enzyme prodrug therapy systems.

Exhaled nitric oxide and asthma in young children

Exhaled nitric oxide (eNO) has been used to diagnose asthma in adults and children using either the slow vital capacity method (SVCm) or, in younger children, the tidal breathing method (TBm). Adenosine 5'-monophosphate (AMP) challenge also has been found to be a sensitive and specific test for the diagnosis of asthma. In the present study, we used the AMP provocation concentration that caused wheezing (PCW) to confirm the diagnosis of asthma (PCW < or = 200 mg/mL). We studied 36 children (2-7 years) with mild intermittent asthma, 13 children (3-7 years) with moderate persistent asthma treated with inhaled steroids, 20 nonasthmatic children (2-7 years) with chronic cough and recurrent pneumonia, and 15 healthy children (4-6 years). Expired gas was collected in collection bags by the TBm, and eNO was measured. We evaluated the efficacy of eNO values in diagnosing asthma. The mean eNO level of the mild intermittent asthmatic children (5.6 +/- 0.4 ppb) not receiving inhaled corticosteroids was significantly higher (ANOVA P < 0.0001) than that of the moderate persistent asthmatics who were treated with inhaled steroids, the nonasthmatic children with chronic cough, and the group of healthy children (3.7 +/- 0.6 ppb, P < 0.05; 3.2 +/- 0.3 ppb, P < 0.001; 2.2 +/- 0.2 ppb, P < 0.001, respectively). The points of intersection for sensitivity and specificity curves of eNO to differentiate mild intermittent asthmatics from nonasthmatic children with chronic cough and from healthy children were 77% and 88% for eNO values of 3.8 ppb and 2.9 ppb, respectively. We conclude that eNO collected by the TBm can differentiate steroid-naive young children with intermittent asthma from healthy children, from nonasthmatic children with chronic cough, and from asthmatic children treated with inhaled steroids.

Can peak expiratory flow measurements estimate small airway function in asthmatic children?

BACKGROUND

Asthma is characterized in part by small airways dysfunction. Peak expiratory flow (PEF) measurement has been suggested by all international guidelines as an important tool in asthma management. The correlation between PEF and FEV(1) but not with forced expired flow at 50% of vital capacity (FEF(50)) is well-established.

STUDY OBJECTIVE

To determine the value of PEF measurement as a predictor of small airways status as expressed by FEF(50).

DESIGN

Analysis of the association between PEF and FEF(50) in single and multiple determinations.

PATIENTS

One hundred eleven asthmatic children (mean age, 11.8 years), grouped in the following way according to FEV(1) values: within normal range (n = 46); mildly reduced FEV(1) (n = 44); and moderately/severely reduced FEV(1) (n = 21).

RESULTS

Overall, FEF(50) and PEF were significantly correlated (r = 0.49; p < 0.0001). However, in 41.6% of the patients, the actual FEF(50) differed by > 20% from the calculated FEF(50). PEF has a high specificity (82.4%) but a poor sensitivity (51.7%) to detect FEF(50) status. PEF was better able to reflect abnormal FEF(50) in the patients with more severe asthma and to reflect normal FEF(50) values in the healthier patients. In patients with multiple measurements (n = 40), the correlation between FEF(50) and PEF was significantly better than that derived from a single determination (multiple measurements r = 0.77; single measurement, r = 0.49).

CONCLUSIONS

Although PEF is an important tool in the management of asthmatic patients, it does not yield a complete picture because it is not sensitive in detecting small airways function. It is best used at home along with regular spirometry measurements at the clinic. PEF may serve as a better index of changes in small airways function once an individual regression is determined.

Housing status and health care service utilization among low-income persons with HIV/AIDS

OBJECTIVE

To examine the impact of housing status on health service utilization patterns in low-income HIV-infected adults.

DESIGN

A survey of 1,445 HIV-infected Medicaid recipients in New York State between April 1996 and March 1997.

MAIN RESULTS

Six percent of study participants were homeless, 24.5% were "doubled-up," and 69.5% were stably housed. Compared with the stably housed, doubled-up and homeless participants were less likely to be seeing a physician regularly (P = .0001), and if seeing a physician, they were likely to have been doing so for a significantly shorter time (P = .02). The homeless were also less likely than either stably housed or doubled-up individuals to see the same physician or group of physicians at each ambulatory visit (P = .007). In addition, a higher proportion of the homeless had made one or more hospital visits over the prior 3 months than the nonhomeless. After multivariate adjustment, doubled-up participants were found to make more emergency room visits, the homeless were less likely to be taking prophylaxis for Pneumocystis carinii pneumonia, and both the doubled-up and the homeless were shown to use slightly more outpatient care than the stably housed.

CONCLUSION

Our study documents differences in health care utilization patterns across stably housed, doubled-up, and homeless HIV-infected persons after controlling for health insurance coverage. These differences, especially those pertaining to outpatient services, suggest that the unstably housed may be receiving less adequate health care than the stably housed, and hence may be more likely to experience adverse clinical outcomes.

Exercise, methacholine, and adenosine 5'-monophosphate challenges in children with asthma: relation to severity of the disease

Bronchial hyperreactivity is a characteristic feature of asthma and can be evaluated by different challenges. The aim of this study was to compare exercise, methacholine (MCH), and adenosine 5'-monophosphate (AMP) challenges in 135 children and young adults (mean age +/- SD, 12.4+/-3.9 years) with asthma, and to examine the utility of the different challenges in predicting those children with asthma likely to require prophylactic antiinflammatory treatment. The sensitivity of MCH challenge in detecting bronchial hyperreactivity (at or below 8 mg/mL) was 98%, that of AMP challenge (at or below 200 mg/mL) 95.5%, and that of exercise (more than 8.2% fall in FEV(1)) was 65%. There was a significant difference between mild asthmatic children (85 patients, intermittent asthma, step 1 of NIH guidelines) and moderate asthmatics (50 patients, steps 2 and 3 of guidelines) in relation to the logarithmic mean provocation concentration to elicit a 20% fall in FEV(1) (PC(20)) to MCH (0.49 mg/mL vs. 0.15 mg/mL, P<0.00001), that to AMP (7.67 mg/mL vs. 3.60 mg/mL, P = 0.001), and in relation to the mean percent fall in FEV(1) after exercise (13.9% vs. 22.0%, P = 0.001). Sensitivity and specificity curves between the two severity groups of asthma were constructed, and the intersection point of the two curves for each type of challenge was determined. When mild asthmatics were compared to moderate asthmatics, the intersection points for MCH, AMP, and exercise were 66%, 63%, and 61%, respectively. Logistic regression analysis and receiver operating characteristic (ROC) curves of the three challenges for the two severity groups of asthma showed that methacholine was a better discriminating challenge between the severity groups than the other two challenges. We conclude that the sensitivities of AMP and MCH challenges in the detection of bronchial hyperreactivity in children and young adults with asthma are very similar and higher than that of exercise. There is a significant difference between mild and moderate asthmatics within the three bronchial challenges, with MCH discriminating better than AMP or exercise between groups.

Efficacy and safety of methacholine bronchial challenge performed by auscultation in young asthmatic children

The measurement of bronchial reactivity is an important aid in the diagnosis of asthma, but the technique using spirometry is not feasible in young children. The aim of the present study was to determine the efficacy and safety of a modification of the chest auscultation method in the assessment of bronchial reactivity to inhaled methacholine in young asthmatic children. One hundred forty-six young children with asthma (mean age, 4.3 yr) underwent bronchial challenges with nebulized methacholine using the auscultation method (PCW). The end point was defined as the appearance of wheezing, oxygen desaturation, or tachypnea. For comparison, 30 children and young adults with asthma underwent bronchial provocation with methacholine using spirometry (PC(20)). A positive response using the auscultation method was observed in 95.9% of the younger children, and wheezes alone or in combination with other signs appeared in 80.8% of them. The mean desaturation at the end point was 4.6% (PCW) and 5.0% (PC(20)), with a similar pattern in the two groups. Cough was not helpful in determining the end point. We conclude that the modified auscultation method is effective and safe, with wheeze appearing at the end point in the large majority of the children.

Pulmonary haemorrhagic syndromes in children

Pulmonary haemorrhage in children is rare and may be either focal or diffuse, idiopathic or associated with an underlying disease. Focal bleeding is usually associated with congenital anomalies or localized acquired disease. Many of the disorders causing diffuse alveolar haemorrhage appear to be immunologically mediated. Treatment modalities include management of the underlying disease and the use of corticosteroids, chloroquine and/or cytotoxic drugs and induce remission in more than half of the patients with diffuse haemorrhage.

Chalcone, acyl hydrazide, and related amides kill cultured Trypanosoma brucei brucei

BACKGROUND

Protozoan parasites of the genus Trypanosoma cause disease in a wide range of mammalian hosts. Trypanosoma brucei brucei, transmitted by tsetse fly to cattle, causes a disease (Nagana) of great economic importance in parts of Africa. T. b. brucei also serves as a model for related Trypanosoma species, which cause human sleeping sickness.

MATERIALS AND METHODS

Chalcone and acyl hydrazide derivatives are known to retard the growth of Plasmodium falciparum in vitro and inhibit the malarial cysteine proteinase, falcipain. We tested the effects of these compounds on the growth of bloodstream forms of T. b. brucei in cell culture and in a murine trypanosomiasis model, and investigated their ability to inhibit trypanopain-Tb, the major cysteine proteinase of T. b. brucei.

RESULTS

Several related chalcones, acyl hydrazides, and amides killed cultured bloodstream forms of T. b. brucei, with the most effective compound reducing parasite numbers by 50% relative to control populations at a concentration of 240 nM. The most effective inhibitors protected mice from an otherwise lethal T. b. brucei infection in an in vivo model of acute parasite infection. Many of the compounds also inhibited trypanopain-Tb, with the most effective inhibitor having a Ki value of 27 nM. Ki values for trypanopain-Tb inhibition were up to 50- to 100-fold lower than for inhibition of mammalian cathepsin L, suggesting the possibility of selective inhibition of the parasite enzyme.

CONCLUSIONS

Chalcones, acyl hydrazides, and amides show promise as antitrypanosomal chemotherapeutic agents, with trypanopain-Tb possibly being one of their in vivo targets.

Gender differences in young adolescents' exposure to violence and rates of PTSD symptomatology

Gender differences in exposure to violence and levels of PTSD symptomatology were examined in a school-based sample of 621 young adolescents. Also investigated as predictors of PTSD symptoms were cognitive coping strategies, perceived social support, and the affective experience of fear. Results support the importance of evaluating gender differences, differentiating between violence by type and location, and considering both cognitive and affective factors as predictors of PTSD symptomatology.

Cut-off points defining normal and asthmatic bronchial reactivity to exercise and inhalation challenges in children and young adults

An analysis was undertaken to determine the optimal cut-off separating an asthmatic from a normal response to a bronchial provocation challenge by exercise and the inhalation of methacholine or histamine in children and young adults. Data were extracted, after appropriate correction, from published studies available in Medline of large random populations that complied with preset criteria of suitability for analysis, and the distribution of bronchial reactivity in the healthy population for exercise and inhalation challenges were derived. Studies on the response to exercise and methacholine inhalation in 232 young asthmatics of varying severity were carried out by the authors and the distribution of bronchial reactivity of a young asthmatic population obtained. Comparisons of the sensitivity and specificity of the challenges were aided by the construction of receiver operating characteristic curves. The optimal cut-off point of the fall in forced expiratory volume in one second (FEV1) after exercise was 13%, with a sensitivity (power) of 63% and specificity of 94%. For inhalation challenges, the optimal cut-off point for the dose of methacholine or histamine causing a 20% fall in FEV1 was 6.6 micromol, with a sensitivity of 92% and a specificity of 89%. The cut-off values were not materially affected by the severity of the asthma and provide objective data with which to evaluate the results of bronchial provocation challenges in children and young adults.

Clinical and genetic risk factors for cystic fibrosis-related liver disease

OBJECTIVE

The aim of this study was to define the role of possible risk factors for the development of cystic fibrosis (CF)-related liver disease and to analyze the association between liver disease and the different genotypes present in the Israeli CF patient population.

PATIENTS AND METHODS

All patients followed at the seven CF centers in Israel were included in this study. Liver disease was determined by persistently elevated serum liver enzymes and/or bilirubin, and/or significant ultrasonographic changes suggestive of chronic liver disease. The following clinical parameters were evaluated: ethnic origin, age at assessment of liver function, sex, history of meconium ileus, pancreatic function, history of distal intestinal obstruction syndrome, pulmonary function, and cystic fibrosis transmembrane conductance regulator mutation analysis.

RESULTS

Of the 288 patients screened, 80 (28%) had liver disease. Of the 256 patients with pancreatic insufficiency, 80 (31%) had liver disease compared with none of the 32 patients with pancreatic sufficiency. Genotype-phenotype correlation was performed on 207 patients carrying identified mutations that were previously classified according to phenotype severity. Liver disease was found in 56 (32%) of 173 patients carrying mutations associated with a severe phenotype and in 6 (38%) of 16 patients carrying at least one mutation associated with a variable genotype (G85E and/or 5T allele). None of the 18 patients carrying the 3849+10kb C->T mutation had liver disease. Prevalence of liver disease increased with age. No correlation was found between liver disease and severity of lung disease, nutritional status, history of meconium ileus, or distal intestinal obstruction syndrome.

CONCLUSION

CF patients who have pancreatic insufficiency and carry mutations associated with a severe or a variable genotype are at increased risk to develop liver disease.

Helix-helix packing angle preferences for finite helix axes

Recently, James Bowie addressed the question of how to normalize correctly the distribution of observed helix-helix packing angles in proteins (Bowie, Nature Struct. Biol. 4:915-917, 1997). A hitherto unrealized yet significant bias toward crossed packing angles was revealed. However, the derived random reference distribution of packing angles requires that helices have to be assumed as infinite in length. Here, we complement Bowie's analysis by consideration of the more realistic case where helices are of finite length. As a result, the statistical bias toward near perpendicular packings appears to be even stronger.

Rehabilitation of hypoxemic patients with COPD at low altitude at the Dead Sea, the lowest place on earth

BACKGROUND

In patients with COPD, oxygen therapy has been shown to improve exercise capacity and survival. Increase in barometric pressure at low altitude can serve as a simple way to improve arterial oxygenation in hypoxemic patients. We have tried to evaluate the effect of staying at low altitude on arterial oxygenation and exercise performance in patients with COPD.

PATIENTS AND METHOD

Eleven patients with COPD (9 male, 2 female) aged 38 to 79 years (mean FEV1, 0.96 L; 36% predicted) with hypoxemia (mean PaO2, 54.2+/-8.9 mm Hg) at Jerusalem (altitude 800 m above sea level) were taken down to the Dead Sea area (altitude 402 m below sea level) for 3 weeks. At both locations we tested arterial blood gases, spirometry, progressive exercise, 6-minute walking distance, and sleep oximetry. The study was repeated 2 weeks after returning to Jerusalem.

RESULTS

Spirometry results were unchanged. Mean arterial PaO2 rose from 54.2+/-8.9 mm Hg to 69.5+/-11 at the first week and to 66.6+/-11 at the third week of stay (p<0.001). PaCO2 rose from 43.5+/-9.8 mm Hg to 47.7+/-9 and 49.5+/-8.4 (p<0.006). Six-minute walking distance rose from 337+/-107 m to 449+/-73 and 507+/-91 in the third week (p<0.005). Maximum oxygen consumption (VO2max) rose from 901+/-257 mL/min to 1,099+/-255 and 1,063+/-250 mL/min (p=0.01). Sleep oximetry showed an increase in mean sleep arterial oxygen saturation from 86.0+/-4.3% to 89.9+/-4.2% and 88.3+/-3.0 at 1 and 3 weeks, respectively (p<0.05). Following the return to Jerusalem, arterial gases returned to their baseline levels (PaO2, 52.9+/-9.4 mm Hg) but 6-min walking distance remained significantly high, 453+/-47 (p<0.02), and VO2max remained high as well (1,102+/-357 mL/min), although it did not reach statistical significance.

CONCLUSIONS

Decline to low altitude or staving at high oxygen environment improves arterial oxygenation and exercise capacity in hypoxemic patients residing in moderate or high altitude. Low altitude (or pressurized wards) can improve pulmonary rehabilitation of hypoxemic patients with COPD.

Lack of large, homozygous deletions of the nephronophthisis 1 region in Joubert syndrome type B. APN Study Group. Arbeitsgemeinschaft für Pädiatrische Nephrologie

Joubert syndrome type B (JSB) is a developmental disorder of the nephronophthisis (NPH) complex with multiple organ involvement, including NPH, coloboma of the eye, aplasia of the cerebellar vermis, and the facultative symptoms of psychomotor retardation, polydactyly, and neonatal tachypnea. In isolated autosomal recessive NPH type 1 (NPH1), homozygous deletions have been described as causative in more than 80% of patients. Since different combinations of the extrarenal symptoms with NPH occur in JSB, a contiguous gene deletion syndrome in the NPH1 genetic region would seem a highly likely cause for JSB. We therefore examined 11 families with JSB for the presence of extended deletions at the NPH1 locus. Genomic DNA was examined using four consecutive polymerase chain reaction (PCR) markers that are deleted in NPH1 and three PCR makers flanking the NPH1 deletion. In all seven markers examined, there was no homozygous deletion detected in any of the 11 JSB families studied. Since these markers saturate the NPH1 deletion region at high density, this finding excludes the presence of large homozygous deletions of the NPH1 region in these JSB families, making it unlikely that deletions of the NPH1 region are a primary cause for JSB.

Gene-directed enzyme prodrug therapy: quantitative bystander cytotoxicity and DNA damage induced by CB1954 in cells expressing bacterial nitroreductase

Clones of human colon carcinoma (WiDr), ovarian carcinoma (SK-OV-3), and Chinese hamster V79 cells expressing the nitroreductase enzyme (NR) from E. coli B were 52-, 225- and 177-fold respectively more sensitive to a 24-h incubation with the prodrug 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) than the parent lines. The IC50s of non-NR-expressing bystander cells were measured in the presence of differing proportions of NR-expressing cells. The shift in IC50 was used to calculate a value for the bystander effect, termed the transmission efficiency (TE), which is the decrease in IC50 due to bystander effect as a percentage of the maximum decrease possible. The percentage of NR-expressing cells for which the TE was 50%, (the TE50) is a single datum of bystander efficacy. WiDr and V79 cell lines, had a similar TE50 of approximately 2%. SK-OV-3 gave a lower value of 0.3%. These TE50 correlate with concentrations of cytosolic NR activity, which is distinguished from endogenous DT diaphorase activity by kinetic differences. A novel method is described which enables both DNA crosslinks and drug-induced single-strand breaks to be simultaneously quantified in a sedimentation assay. Using this technique, bystander DNA damage was demonstrated in V79 cells, of approximately 50% of that in activator cells.

The adjacent yeast genes ARO4 and HIS7 carry no intergenic region

The region between the open reading frames of the adjacent yeast genes ARO4 and HIS7 consists of 417 base pairs (bp). Termination of ARO4 transcription and initiation of HIS7 transcription has to take place within this interval, because both genes are transcribed into the same direction. We show that the ARO4 terminator and the HIS7 promoter are spatially separated, nonoverlapping units. The ARO4 terminator includes 84 bp of the ARO4 3'-untranslated region with several redundant ARO4 3' end processing signals. Deletion of the ARO4 terminator does reduce but not completely shut down its expression. The adjacent region of 40 bp is neither required for correct ARO4 3' end formation nor for HIS7 initiation but contains the nucleotides corresponding to the wild type mRNA 3' ends. The following 280 bp are required for the HIS7 promoter. Replacement of the housekeeping ARO4 promoter by the stronger ACT1 promoter leads to reduced HIS7 expression due to transcriptional interference. This underlines the compactness of the yeast genome carrying virtually no intergenic regions between adjacent genes.

[Infantile type Bland-White-Garland syndrome as a cause of death in Rh incompatibility]

The faulty origin of the left coronary artery from the pulmonary artery is with an incidence of 1:300,000 newborns a very rare heart defect. We report a case of a pregnancy with two intrauterine blood transfusions in the 30th and 32nd week of gestation because of Rh-incompatibility and fetal anaemia. Dopplersonographic and echocardiographic parameters were normal. In the 32nd week of gestation delivery was induced (birth weight 2240 g, cord pH value 7.35, Apgar-score 8/9/9). Under a therapy with respiration, blood exchange transfusion and cardiotonic drugs the newborn died in the second week. The autopsy showed a general immaturity, a haemosiderosis of spleen, liver and lungs, a marked cellular jaundice and signs of a multi-organ-failure. The sinus of the pulmonary valve was the origin of the left coronary artery. In case of a seriously impaired pumping action and after exclusion of other heart defects the Bland-White-Garland-Syndrome (BWGS) has to be considered. Although a prenatal diagnosis of BWGS is with high resolution-ultrasound possible, the early postnatal diagnosis seems to be more relevant.

Regulation of the yeast HIS7 gene by the global transcription factor Abf1p

The HIS7 gene of Saccharomyces cerevisiae encodes a bifunctional glutamine amidotransferase: cyclase that catalyzes the formation of biosynthetic precursors for histidine and adenine. HIS7 is activated by Gcn4p upon amino acid starvation and by the Bas1/2p complex in response to adenine limitation. Mutation analysis of the HIS7 promoter in a deltagcn4 background revealed a polyd(A/T) stretch and a d(CT) repeat as essential elements for Gcn4p-independent basal HIS7 transcription. The protein binding this element was enriched and identified as the multifunctional DNA-binding protein Abf1p. Abf1p binds specifically to the d(CT) repeat sequence, which represents a novel Abf1p-binding motif, and protects 17 nucleotides from digestion by DNase I. In addition, Abf1p binding causes bending of the HIS7 promoter structure.

Yield from flexible bronchoscopy in children

Flexible fiberoptic (FO) bronchoscopy can now be undertaken readily in children using topical anesthesia and light sedation and has largely supplanted rigid open tube (OT) bronchoscopy for diagnostic purposes. The present study examined the contribution of the FO bronchoscope to clinical management in children presenting with specific types of problems. We examined the first 200 consecutive flexible bronchoscopies performed in 1995 in children under 18 years of age (median age, 2.27 years). Indications for bronchoscopy were noisy breathing (26.5%), recurrent pneumonia (21.0%), suspected pneumonia in an immunocompromised patient (10.5%), atelectasis or bronchial toilet (12.5%), possible foreign body aspiration (13.0%), and miscellaneous other reasons (16.5%). Inspection of the airway was abnormal in 67.0% of all investigations and made a clinically meaningful contribution to management in 67.5%, especially in those with noisy breathing (98.1%), possible foreign body aspiration (100%), and atelectasis (76.0%). Bronchoalveolar lavage (BAL) cytology was abnormal in 80.4% of the 107 lavages, but contributed little to management except in those with recurrent pneumonia (73.8%). Bacteria were isolated in 26.6% of the 109 specimens cultured, but this finding rarely affected management. Fungi were isolated in 47.4% of the 19 lavages in the immunocomprised group. Together, inspection, BAL and microbiology contributed to management in a mean of 90.5% (range, 76.2-100%) of patients in the various groups. We concluded that a high yield of clinically meaningful information can be expected from FO bronchoscopy in children when coupled with BAL and microbiological studies of lavage fluid.

[Color Doppler ultrasound of uterine, fetoplacental and fetal blood vessels in the 2nd trimester in normal pregnancies]

We investigated 69 healthy women with normal pregnancy and delivery in order to establish normal values for the second trimester of gestation. In a cross-sectional study we measured the pulsatility index (PI), the maximal systolic velocity (V-MAX) and the mean velocity (V-MEAN) in the uterine arteries (UAA), the umbilical artery (UA), the fetal thoracic aorta (FTA) and the middle cerebral artery (MCA) from the 14th to the 24th week of gestation. A regression analysis shows a significant slope of the PI of UAA and UA (p < 0.01), whereas in contrast to the UA there is no significant difference of the median values of the UAA-PI from the 18th week of gestation. With progressive gestation V-MEAN of UAA increases more (p < 0.001) than V-MAX (p < 0.05) as a result of the increasing diastolic blood flow. In the UA there is also a significant rising trend of V-MAX and V-MEAN (p < 0.0001). No significant changes of the PI of FTA and MCA are seen, although there is a slight increasing trend. After the 20th week in the MCA a marked tendency to high PI-values is observed, whereas there is a change between different flowpatterns prior to the 20th week. V-MAX and V-MEAN of FTA increases significantly, but there is no change in the MCA. Our results for UAA and UA correspond to the known morphologic changes in the utero- and fetoplacental vessels in the second trimester and are comparable to other results. Particularly the physiology of the cerebral perfusion needs to be investigated more intensively. These normal values provide a good basis for early and complex assessment of a disturbed perfusion in the second trimester.

[Multivariate analysis of the significance of vaginal bacterial colonization in the occurrence of a preterm birth with various risk parameters]

Using a discriminance analysis we investigated the interactions between parameters of the vaginal flora and subclinical infection regarding preterm birth. The prospective study includes 222 single pregnancies, 114 of them with preterm labour or premature rupture of the membranes (PROM). The analysis includes information of a vaginal/ cervical smear (total number of pathogenic germs, species and groups of pathogenic germs), vaginal pH, maternal white blood cell count (WBC), C-reactive protein (CRP) and temperature. A normal vaginal flora was found in only 19%. Pregnancies with preterm labour have a higher quantity of pathogenic germs, whereas there is no difference of the germ group distribution. Moreover, pregnancies with preterm labour and 2 or 3 pathogenic germs have a higher rate of preterm birth. The discriminance analysis shows that only the affiliation the risk group with preterm labour and the parameters CRP and WBC have a significant selectivity for consequent preterm birth, but not the parameters containing information of the vaginal flora. The same is valid for the group with preterm labour, where only the parameters PROM and WBC are able to select significantly for preterm birth.

The transcriptional apparatus required for mRNA encoding genes in the yeast Saccharomyces cerevisiae emerges from a jigsaw puzzle of transcription factors

The number of identified yeast factors involved in transcription has dramatically increased in recent years and the understanding of the interplay between the different factors has become more and more puzzling. Transcription initiation at the core promoter of mRNA encoding genes consisting of upstream, TATA and initiator elements requires an approximately ribosome-sized complex of more than 50 polypeptides. The recent identification and isolation of an RNA polymerase holoenzyme which seems to be preassembled before interacting with a promoter allowed a better understanding of the roles, assignments and interplays of the various constituents of the basal transcription machinery. Recruitment of this complex to the promoter is achieved by numerous interactions with a variety of DNA-bound proteins. These interactions can be direct or mediated by additional adaptor proteins. Other proteins negatively affect transcription by interrupting the recruitment process through protein-protein or protein-DNA interactions. Some basic features of cis-acting elements, the transcriptional apparatus and various trans-acting factors involved in the initiation of mRNA synthesis in yeast are summarized.