Emergence of bedaquiline-resistant tuberculosis and of multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis strains with rpoB Ile491Phe mutation not detected by Xpert MTB/RIF in Mozambique: a retrospective observational study

BACKGROUND

In 2021, an estimated 4800 people developed rifampicin-resistant tuberculosis in Mozambique, 75% of which went undiagnosed. Detailed molecular data on rifampicin-resistant and multidrug-resistant (MDR) tuberculosis are not available. Here, we aimed at gaining precise data on the determinants of rifampicin-resistant and MDR tuberculosis in Mozambique.

METHODS

In this retrospective observational study, we performed whole-genome sequencing of 704 rifampicin-resistant Mycobacterium tuberculosis complex (Mtbc) strains submitted to the National Tuberculosis Reference Laboratory (NTRL) in Maputo, Mozambique, between 2015 and 2021. Phylogenetic strain classification, genomic resistance prediction, and cluster analysis were performed.

FINDINGS

Between Jan 1, 2015, and July 31, 2021, 2606 Mtbc isolates with an isoniazid or rifampicin resistance were identified in the NTRL biobank, of which, 1483 (56·9%) were from men, 1114 (42·7%) from women, and nine (0·4%) were unknown. Genome-based drug-resistant prediction classified 704 Mtbc strains as rifampicin resistant. 628 (89%) of the 704 Mtbc strains were classified MDR; of those, 146 (23%) were pre-extensively drug resistant (pre-XDR; additional fluoroquinolone resistance), and 24 (4%) extensively drug resistant (XDR; combined fluoroquinolone and bedaquiline resistance). Overall, 61 (9%) of 704 strains revealed resistance to bedaquiline: five (7%) of 76 rifampicin resistant plus bedaquiline resistant, 32 (7%) of 458 MDR plus bedaquiline resistant, and 24 (100%) of 24 XDR. Prevalence of bedaquiline resistance increased from 3% in 2016 to 14% in 2021. The cluster rate (12 single-nucleotide polymorphism threshold) was 42% for rifampicin-resistant strains, 78% for MDR strains, 94% for pre-XDR strains, and 96% for XDR Mtbc strains. 31 (4%) of 704 Mtbc strains, belonging to a diagnostic escape outbreak strain previously described in Eswatini (group_56), had an rpoB Ile491Phe mutation which is not detected by Xpert MTB/RIF (no other rpoB mutation). Of these, 23 (74%) showed additional resistance to bedaquiline, 13 (42%) had bedaquiline and fluoroquinolone resistance, and two (6%) were bedaquiline, fluoroquinolone, and delamanid resistant.

INTERPRETATION

Pre-XDR resistance is highly prevalent among MDR Mtbc strains in Mozambique and so is bedaquiline resistance; and the frequency of bedaquiline resistance quadrupled over time and was found even in Mtbc strains without fluoroquinolone resistance. Importantly, strains with Ile491Phe mutation were frequent, accounting for 31% (n=10) of MDR plus bedaquiline-resistant strains and 54% (n=13) of XDR Mtbc strains. Given the current diagnostic algorithms and treatment regimens, both the emergence of rifampicin resistance due to Ile491Phe and bedaquiline resistance might jeopardise MDR tuberculosis prevention and care unless sequencing-based technology is rolled out. The potential cross border spread of diagnostic escape strains needs further investigation.

FUNDING

The German Ministry of Health through the Seq_MDRTB-Net project, the Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy Precision Medicine in Inflammation and the Research Training Group 2501 TransEvo, the Leibniz Science Campus Evolutionary Medicine of the Lung, and the German Ministry of Education and Research via the German Center for Infection Research.

Quantification of residual pneumoperitoneum after robotic-assisted laparoscopic surgery

Objective

Laparoscopic surgery improves the postoperative recovery process and relies on CO2 insufflation to establish the operative field. Most residual CO2 is expelled prior to port and incision closure. Computed tomography (CT) is often used to assess an acute abdomen and is highly sensitive in detecting free intra-abdominal air – the hallmark sign of a bowel injury. Yet, the clinical significance of free air in the early postoperative period is confounded by residual CO2 and is not usually due to a visceral injury. The aim of this prospective study was to systematically quantify the residual pneumoperitoneum (RPP) at varying timepoints after robotic-assisted laparoscopic surgery.

Methods

Patients undergoing robot-assisted laparoscopic intervention, both radical prostatectomies and left hemicolectomies, were prospectively enrolled in the study. At the conclusion of each operation, manual abdominal pressure was applied to aid in exsufflation of residual CO2. Very-low-dose CT scans were performed on postoperative days (POD) 3, 5, and 7, with subsequent volumetric quantification of RPP. To investigate potential factors influencing the quantity of RPP, correlation plots were made against BMI, age, operative time, total insufflation volume, intra-abdominal pressure, time to flatus and first bowel movement, pain score, and postoperative analgesic requirement.

Results

Thirty-one patients undergoing robotic assisted laparoscopic prostatectomy were untill now enrolled in the study, of which only one experienced a Clavien-Dindo 2 complication; all others were free of any complications during post-operative assessment period. On POD3, 5, and 7, 97%, 94%, and 68% of patients, respectively, demonstrated RPP. The RPP volumes were noted to be 9.6 mL (IQR = 3.9-31.8; maximum = 247 mL) on POD3, 1.0 mL (0.1-5.1; maximum = 221 mL) on POD5, and 0.08 mL (1-1.2; maximum = 112 mL) on POD7. A significant correlation was only appreciated between RPP volume and BMI; those with higher BMIs had lower initial volumes of RPP on POD3 and exhibited a more rapid decrease in RPP over one week.

Conclusion

One week after robot-assisted laparoscopic operations, a majority of patients will exhibit clinically insignificant RPP, even with volumes as high as 250 mL. Larger patients tend to have smaller residuals of CO2. Our data provide new basic knowledge regarding RPP and may help to interpret postoperative CT-scans.

When hydrogen bonding overcomes Coulomb repulsion: from kinetic to thermodynamic stability of cationic dimers

Quantum chemical calculations have been employed to study the kinetic and thermodynamic stability of hydroxy-functionalized 1-(3-hydroxyalkyl)pyridinium cationic dimers. For [Py-(CH2)n-OH+]2 structures with n = 2-17 we have calculated the robust local minima with clear dissociation barriers preventing their "Coulomb explosion" into separated cations. For n = 15 hydrogen bonding and dispersion forces fully compensate for the repulsive Coulomb forces between the cations allowing for the quantification of the pure hydrogen bond in the order of 20 kJ mol-1. The increasing kinetic stability even turns to thermodynamic stability with further elongated hydroxyalkyl chains. Now, quantum-type short-range attraction wins over classical long-range electrostatic repulsion resulting in negative binding energies and providing the first thermodynamically stable cationic dimers. The electronic, structural and spectroscopic signatures of the cationic dimers could be correlated to NBO parameters, supporting the existence of anti-electrostatic hydrogen bonds (AEHB) as recently suggested by Weinhold. In principle, these pure cationic dimers should be detectable in gas-phase experiments at low temperatures without the need of mediating molecules or counteranions.

Computed tomography for pulmonary embolism: assessment of a 1-year cohort and estimated cancer risk associated with diagnostic irradiation

BACKGROUND

The principal concern of any radiation exposure in computed tomography (CT) is the induction of stochastic risks of developing a radiation-induced cancer. The results given in this manuscript will allow to (re-)calculate yield of chest CT.

PURPOSE

To demonstrate a method to evaluate the lifetime attributable risk (LAR) of cancer incidence/mortality due to a single diagnostic investigation in a 1-year cohort of consecutive chest CT for suspected pulmonary embolism (PE).

MATERIAL AND METHODS

A 1-year cohort of consecutive chest CT for suspected PE using a standard scan protocol was analyzed retrospectively (691 patients, 352 men, 339 women). Normalized patient-specific estimations of the radiation doses received by individual organs were correlated with age- and sex-specific mean predicted cancer incidence and age- and sex-specific predicted cancer mortality based on the BEIR VII results. Additional correlation was provided for natural occurring risks.

RESULTS

LAR of cancer incidence/mortality following one chest CT was calculated for cancer of the stomach, colon, liver, lung, breast, uterus, ovaries, bladder, thyroid, and for leukemia. LAR remains very low for all age and sex categories, being highest for cancer of the lungs and breasts in 20-year-old women (0.61% and 0.4%, respectively). Summation of all cancer sites analyzed raised the cumulative relative LAR up to 2.76% in 20-year-old women.

CONCLUSION

Using the method presented in this work, LAR of cancer incidence and cancer mortality for a single chest CT for PE seems very low for all age groups and both sexes, but being highest for young patients. Hence the risk for radiation-induced organ cancers must be outweighed with the potential benefit or a treatment and the potential risks of a missed and therefore untreated PE.

[Inicidental finding: patient with cervical spine trauma]

An ossification of the posterior longitudinal ligament, often presenting asymptomatically, can cause a symptomatic myelopathy after trauma. Keeping this entity in mind in daily clinical routine will help in making the correct diagnosis and in administering the corresponding therapy.

Detection of urolithiasis using low-dose CT--a noise simulation study

How does an acquisition at reduced doses using automatic tube current modulation techniques compare to the normal standard dose CT? Does it affect the sensitivity for detection of calcifications? CT raw data of 54 patients with suspected urolithiasis acquired with automatic tube current modulation techniques were used for image noise simulations with 100%, 50% and 25% dose simulated. Data were analyzed by independent readers with regard to the presence of urolithiasis, stone location, size, density and differential diagnoses. The mean effective dose per standard examination/50%/25% simulation was 7.3 mSv/3.8 mSv/1.9 mSv. Sensitivities/specificities for detection of urolithiasis were calculated for all dose simulations and resulted in 0.94/0.98 in the 50% dose level group and 0.82/0.97 in the 25% dose level group. Low-dose CT with tube current modulation can be used as a standard procedure for the evaluation of patients with suspected acute renal colic.

[Confusion, gait ataxia and ophthalmoplegia in a patient with chronic alcohol consumption]

Wernicke encephalopathy is a neurological disorder, often caused by a lack of thiamine. Immediate diagnosis and therapy are important to prevent significant morbidity and mortality. Based on a clinical case radiologic imaging features on MRI are demonstrated.

[Alcoholism and possible consequences for the central nerval system - pontine and extrapontine myelinolysis]

The central pontine and extrapontine myelinolysis is an important entity in the neurology disorders in the context with alcohol abuse. Though often first based on clinical characteristics, the diagnosis can be often supported with radiologic imaging.

Transthoracic sonography for the detection of pulmonary embolism--a meta-analysis

PURPOSE

Radiation protection is a major issue since the implementation of MSCT technology and its widespread indication for the detection of various diseases. In a European-wide trial (SECT) meta-analyses of imaging alternatives to CT have been initiated. This paper focuses on the diagnostic performance of transthoracic ultrasound (TUS) for the diagnosis of pulmonary embolism (PE) (5 studies, 652 patients).

MATERIALS AND METHODS

Medical literature (from 1990 to 2006) in PubMed and EMBASE databases was searched for articles on studies that used TUS as diagnostic tests for PE. Studies were included if they reported the positive and negative rates of PE diagnoses from TUS compared with the rates of PE in CT, MRI or a combination of diagnostic tests. Two readers assessed the quality of the studies.

RESULTS

Pooled sensitivity and specificity of TUS for PE were 80 % (95 % CI: 75 %, 83 %) and 93 % (95 % CI: 89 %, 96 %), respectively.

CONCLUSION

In the time of MSCT, TUS is an imaging modality that is no longer part of recent diagnostic algorithms for the diagnosis of PE. Considering the increasing number of requested CT examinations and therefore increasing collective radiation dose, this meta-analysis shows that TUS is a diagnostic alternative for special clinical settings in the work-up of suspected PE that seems to have fallen into oblivion.

[Surgical strategies in the treatment of acute diverticular disease--a retrospective analysis of surgical patients at the hospital "Städtisches Klinikum Brandenburg an der Havel"]

BACKGROUND

Depending on the degree of severity of acute diverticular disease, operative therapy is performed as an emergency, urgent or elective resection. A challenge is posed not only by the decision on whether to opt for conservative therapy or speedy resection, but also, when resection is indicated, by choosing the most suitable procedure (primary anastomosis or discontinuity resection). The frequency of use of the various therapeutic concepts and their success rates were studied in our clinic.

METHODS

All cases of acute sigmoid diverticulitis (108) surgically treated in the Klinikum Brandenburg from 2003 to 2005 were analysed retrospectively.

RESULTS

17 patients (15.7 %) underwent emergency resection with primary anastomosis (8) (of these, 4 were with additional protective stoma) or Hartmann procedure (9). 17 patients (15.7 %) required urgent laparotomy, 11 needed primary anastomosis (protective stoma in 8 patients) and the Hartmann procedure was performed in 3 patients. In 2 patients the laparotomy was limited to colostomy with drainage without resection because of the high cardiac risk under anaesthesia. Of 49 patients (45.4 %), 25 underwent elective resection via laparotomy, and 24 via laparoscopy, with protective stomas in 4 and 3 patients, respectively. 25 patients (23.1 %) were treated conservatively: in 8 cases a later resection was recommended. Revision was necessary in 10 cases due to anastomosis dehiscence (4), bleeding (1), stoma necrosis (2), ileus (1), wound dehiscence (1) or for programmed lavage after free perforation with faecal peritonitis (2). 3 multimorbid patients died after emergency laparotomy.

CONCLUSION

A concept of staged treatment can reduce the number of emergency laparotomies; it provides for early focus removal in cases which cannot be managed adequately with conservative treatment and aims for the largest possible number of elective resections.

[Kissing osteochondroma of the lower limb]

As definition, a "kissing" osteochondroma is a typical new bony formation with erosion on the adjacent paired bone, provoked by pressure of the outgrowth. Further diagnostics for incidentally diagnosed solitary osteochondroma should be performed only in cases where malignant transformation is suspected.

[Portal vein thrombosis in a young patient with severe abdominal pain: a case report]

Wir berichten über einen Patienten mittleren Alters mit gürtelförmigen Oberbauchschmerzen, bei welchem nebst einer chronischen zusätzlich eine subakute Thrombose der kavernös transformierten und stark verkalkten Portalvene duplexsonographisch und computertomographisch nachgewiesen wurde. Eine Vollliqueminisierung und anschliessende Marcoumarisierung führte zur Besserung der Symptomatik.

[Intercostal tumors: diagnostic pitfalls]

Aussagen in radiologischen Befunden über die Dignität asymptomatischer interkostaler Raumforderungen sind mit Vorsicht zu treffen. Auch radiologisch zunächst benigne erscheinende Läsionen können sich, wie in beiden vorliegenden Fällen, als bösartig entpuppen. Metastasen eines malignen Melanoms können sich atypisch präsentieren und dadurch leicht verkannt werden. Schwannome im Rahmen einer Neurofibromatose Typ 1 können maligne entarten. Generell ist bei einer interkostalen Raumforderung die Differentialdiagnose eines malignen Tumors immer in Betracht zu ziehen, nicht zuletzt um den Weg für eine adäquate Therapie zu ebnen.

Survival trends among Danish patients undergoing coronary angiography for known or suspected ischaemic heart disease: a population based follow up study, 1992-2000

OBJECTIVE

To determine, from population based clinical data, changes in the survival of Danish patients examined by coronary angiography for known or suspected ischaemic heart disease (IHD) during the 1990s.

DESIGN

Follow up study.

SETTING

The departments of cardiology at Rigshospitalet, Copenhagen University Hospital, and Skejby Hospital, Aarhus University Hospital, Denmark.

PATIENTS

Patients with IHD (n = 7021) who underwent first time coronary angiography in 1992, 1996, or 2000.

MAIN OUTCOMES MEASURES

Three year survival was compared between cohorts and with that of the general population. Cox proportional hazards regression was used to estimate mortality ratios adjusted for differences in patient characteristics.

RESULTS

Survival improved substantially--for example, adjusted mortality ratio was 0.69 (95% confidence interval (CI) 0.55 to 0.87) when comparing patients from 2000 with patients from 1992. The absolute standardised survival rates after three years of follow up were 87.1% (95% CI 85.4% to 88.8%), 89.9% (95% CI 88.5% to 91.3%), and 91.2% (95% CI 90.3% to 92.1%) among patients examined in 1992, 1996, and 2000, respectively. The improvement was not explained by the improvement in overall survival in the general population during the study period.

CONCLUSIONS

The survival of Danish patients with known or suspected IHD appears to have improved substantially during the 1990s.

Prognostic impact of different regional referral practices for interventional investigation and coronary treatment after exercise testing: a population-based 5-year follow-up study

OBJECTIVE

To examine the association among different centres' referral practices for coronary angiography (CAG) after exercise testing, with 1- and 5-year outcomes.

DESIGN

Observational population-based cohort study.

SETTING

All 10 hospitals and six private practising consultants in Aarhus and Ringkjoebing counties (900 000 inhabitants), Denmark.

SUBJECTS

All patients who in 1996 had an abnormal bicycle exercise test (n = 736).

MEASUREMENTS

Referral for CAG, coronary intervention, cardiovascular and all-cause mortality, and myocardial infarction (MI).

RESULTS

As an immediate consequence of the exercise test, 60.7% of subjects were referred for CAG. Based on the centres' fraction of patients referred for CAG, three categories of centres were defined: low (<33%), intermediate (33-66%) and high (>66%). A low compared with a high referral fraction was associated with a similar 5-year mortality and MI ratio [all-cause/cardiovascular mortality rate ratio (RR) = 1.33, 95% confidence interval (CI): 0.45-3.92/RR = 0.62, 95% CI: 0.25-1.57; and MI RR = 0.92, 95% CI: 0.45-1.86]. The same was found for an intermediate compared with a high fraction (all-cause/cardiovascular mortality RR = 0.92, 95% CI: 0.49-1.72/RR = 0.74, 95% CI: 0.42-1.33; and MI RR = 1.07, 95% CI: 0.68-1.70). Estimates were about the same after 1 year of follow-up with no major differences among centres in mortality or MI.

CONCLUSIONS

Centres' different referral practices for interventional investigation and treatment were not associated significantly with short-term or long-term mortality or MI among patients with an abnormal exercise test.

Ovarian 'tumor' of the adrenogenital syndrome: the first reported case

We report the case of a 36-year-old woman with congenital adrenal hyperplasia from 21-hydroxylase deficiency who had been receiving replacement therapy with corticosteroids since birth. At the age of 35 years, she developed abrupt aggravation of her virilizing symptoms and underwent an adrenalectomy and partial left oophorectomy. Persistent virilization and high testosterone levels led to right oophorectomy and completion left oophorectomy 6 months later. Each adnexa contained ovarian or paraovarian soft brown masses that on microscopic examination were identical to the testicular tumor of the adrenogenital syndrome. This represents the first reported case of this pathology (well known in the testis) in the ovary.

Epigenetic PTEN silencing in malignant melanomas without PTEN mutation

A tumor suppressor gene at 10q 23.3, designated PTEN, encoding a dual specificity phosphatase with lipid and protein phosphatase activity, has been shown to play an important role in the pathogenesis of a variety of human cancers. Germline mutations in PTEN cause Cowden syndrome (CS), which is characterized by multiple hamartomas and a high risk of breast and thyroid cancers. Frequent loss of heterozygosity at 10q is found in both early and advanced-stage sporadic melanomas; however, mutations or deletions in PTEN are detected mainly in melanoma cell lines. In this study, we examined PTEN expression in 34 unselected sporadic melanomas (4 primary melanomas, 30 metastases) using immunohistochemistry and correlated this with the results of structural studies of this gene. Immunostaining of 34 melanoma samples revealed no PTEN expression in 5 (15%) and low PTEN expression in 17 (50%), whereas the rest of the tumors (35%) had high levels of expression. Hemizygous deletion was found in 32% of the tumors but neither intragenic PTEN mutation nor biallelic deletion was found in any of the samples. Of the 5 melanomas showing no PTEN expression, 4 had no mutation or deletion of PTEN. Of the 13 tumors having weak PTEN immunoreactivity and informative loss of heterozygosity results, 6 had evidence of hemizygous allelic loss of PTEN while the remaining 7 had intact PTEN. These results strongly support PTEN as a major tumor suppressor on 10q involved in melanoma tumorigenesis and suggest an epigenetic mechanism of biallelic functional inactivation not previously observed in other cancers where PTEN might be involved.

Regional variations in the use of diagnostic coronary angiography. A one-year population-based study of all diagnostic coronary angiographies performed in a rural and an urban Danish county

The aim of this study was to monitor coronary angiography activity and results, and to evaluate indications and treatment consequences using regional hospital registers and case records in the rural county of Ringkjøbing and urban county of Aarhus The study included all patients who had undergone a coronary angiography during 1996. For women, there were 606 (rural) and 1296 (urban) coronary angiographies per one million inhabitants (p < 0.0001) and for men, 1884 (rural) and 3051 (urban) coronary angiographies per one million inhabitants (p < 0.0001). In both counties the age distribution of the women examined was the same as that for the men. The angiographic rates were the same in the two counties for patients examined for valvular heart disease and severe arrhythmias. For patients with ischaemic heart disease, the angiographic rate for rural patients was two to three times lower than that for urban patients (p < 0.01). Revascularization procedures were performed in 39% (rural) and 40% (urban) of the examined women (NS) and 66% (rural) and 59% (urban) of the examined men (p < 0.05). Despite wide regional differences in coronary angiography activity, angiography was deployed to the same extent for examination of patients with valvular and severe arrhythmia heart disease. For patients examined for ischaemic heart disease, angiography activity was considerably lower in the rural area. The female patients had a higher frequency of normal coronary angiograms than the male patients.

Opioid treatment of painful chronic pancreatitis

BACKGROUND

Abdominal pain is the dominant symptom in 50-75% of patients with chronic pancreatitis, often requiring opioid analgesics. Fentanyl, a potent synthetic opioid, can be administered percutaneously at a constant dose and is claimed to have fewer systemic side effects.

AIM

To evaluate transdermal fentanyl plaster versus sustained release morphine tablets as analgesic treatment of painful chronic pancreatitis.

METHODS

In an open randomized crossover trial, 18 patients were included. The treatment period was 4 wk for each drug. All patients had immediate-release morphine tablets as rescue medication.

RESULTS

The dosage of transdermal fentanyl had to be increased on average 50% over that indicated by the manufacturer. When this was done and rescue medication was secured, no difference between the two drugs in primary endpoint or patient preference was observed. There was also no difference in the secondary endpoints, pain control, and quality of life. However, skin side effects, mostly mild, occurred in 44% of the patients during treatment with transdermal fentanyl, and the mean daily dose of immediate release morphine was significantly higher during the transdermal fentanyl period than during the sustained-release morphine period (30.7 mg vs. 14.7 mg [p < 0.01]).

CONCLUSION

When given in an appropriate dose, transdermal fentanyl might be useful for treatment of some patients with painful chronic pancreatitis, e.g., when tablet ingestion is difficult. However, the dosage often has to be increased above that recommended by the manufacturer. The need of rescue morphine is considerable and skin side effects often occur. Transdermal fentanyl is, therefore, not the ideal first-choice analgesic in patients with painful chronic pancreatitis.

Ocular responses to radial optic flow and single accelerated targets in humans

Self-movement in a structured environment induces retinal image motion called optic flow. Optic flow on one hand provides information about the direction of self-motion. On the other hand optic flow presents large field visual motion which will elicit eye movements for the purpose of image stabilization. We investigated oculomotor behavior in humans during the presentation of radial optic flow fields which simulated forward or backward self-motion. Different conditions and oculomotor tasks were compared. In one condition, subjects had to actively pursue single dots in a radial flow pattern. In a second condition, subjects had to pursue single dots over a dark background. These dots accelerated or decelerated similar to single dots in radial optic flow. In a third condition, subjects were asked to passively view the entire optic flow stimulus. Smooth pursuit eye movements with high gain were observed when dots were actively pursued. This was true for single dots moving over a homogeneous background and for single dots in the optic flow. Passive viewing of optic flow stimuli evoked eye movements that resembled an optokinetic nystagmus. Slow phase eye movements tracked the motion of elements in the optic flow. Gain was low for simulated forward self-motion (expanding optic flow) and high for simulated backward movement self-motion (contracting optic flow). Thus, voluntary pursuit and passive optokinetic responses yielded different gain for the tracking of elements of an expanding optic flow pattern. During passive viewing of the optic flow stimulus, gaze was usually at or near the focus of radial flow. Our results give insights into the oculomotor performances and needs for image stabilization during self-motion and in the role of gaze strategy for the detection of the direction of heading.

Helicobacter pylori infection in patients with chronic pancreatitis and duodenal ulcer

BACKGROUND

The prevalence of duodenal ulcer is high in patients with chronic pancreatitis. Patients with simple duodenal ulcer without chronic pancreatitis are mostly Helicobacter pylori-infected, and the prevalence of IgG seropositivity is > 95%. The prevalence of H. pylori infection in patients with chronic pancreatitis is not known.

METHODS

IgG antibodies against H. pylori were measured in a cross-sectional survey of consecutive patients who had their exocrine pancreas function examined with a Lundh meal test in the period 1988-95 and in a control group of patients with simple duodenal ulcer.

RESULTS

Twenty-seven per cent of the patients with chronic pancreatitis had duodenal ulcer during the observation period. The prevalence of IgG antibodies against H. pylori was 22% in patients with chronic pancreatitis without duodenal ulcer as compared with 27% with non-organic abdominal pain. The prevalence of IgG antibodies against H. pylori was 60% in patients with chronic pancreatitis complicated by duodenal ulcer as compared with 86% in controls with simple duodenal ulcer.

CONCLUSIONS

H. pylori infection contributes but may not be the only cause of duodenal ulcer in patients with chronic pancreatitis.

Motion processing for saccadic eye movements during the visually induced sensation of ego-motion in humans

During ego-motion an observer is often faced with the task of controlling his heading direction while simultaneously registering the movement of objects in order to avoid possible obstacles. Psychophysical experiments have shown that the detection of moving objects is impaired by concurrent ego-motion. We investigated the interaction between ego-motion and object-motion by examining the latencies of saccades executed to moving targets under a visually induced sensation of ego-motion. Saccadic latencies increased during this sensation, with a global or non-retinotopic effect of optic flow on motion detection. Furthermore, separating stereoscopically the moving target and the optic flow into foreground and background, respectively, still resulted in increased latencies. We propose that an inhibitory influence of the perception of self-motion exists on the perception of object-motion. These results support a model of space constancy which strives to create a stable world during locomotion.

The influence of stationary and moving textured backgrounds on smooth-pursuit initiation and steady state pursuit in humans

We investigated the effects of stationary and moving textured backgrounds on the initiation and steady state of ocular pursuit using horizontally moving targets. We found that the initial eye acceleration was slightly reduced when a stationary textured background was employed, as compared to experiments with a homogeneous background. When a moving textured background was introduced, the initial eye acceleration was significantly larger when the target and the background moved in opposite directions than when the target and the background moved in the same direction. The use of stationary and moving textured backgrounds resulted in comparable effects on the initial eye acceleration when they were presented either as a large field or as a narrow, horizontal small field, only covering the trajectory of the target. Moreover, small-field stationary backgrounds slightly reduced the eye velocity during steady state pursuit. A small-field background moving in the opposite direction to the target distinctly reduced eye velocity, while a target and a background moving in the same direction sometimes even improved pursuit performance, when compared with a homogeneous background. The influences of small-field textured backgrounds on steady state pursuit were comparable with those of large-field backgrounds in both stationary and moving conditions.

Visual inspection of three-dimensional objects by human observers

Eye movements are an important aid in active visual exploration of the environment and in performing behavioural tasks. Eye movements might also play a role in human perception of three-dimensional (3-D) objects. Eye-movement strategies were investigated when humans inspected and memorised 3-D objects. Subjects were instructed to memorise the 3-D structure of parts of statues of human figures placed on a turntable free to rotate through 360 degrees. Eye movements and turning behaviour were recorded. Different turning and eye-movement strategies could be observed. Subjects showed individual turning behaviours that were reproducible between trials. Turning strategies ranged from focusing on only a limited number of perspective views to almost continuously rotating the object with only short stops. On average twelve-thirteen views were inspected during memorising. Eye movements also revealed individual strategies. Fixation locations within each inspection view ranged from either closely spaced on isolated parts of the object to distributed over the whole view with large saccades in between. Eye movements were often directed to the same details from different perspectives. The differences in turning and viewing strategy also resulted in differences in the ability to recognise parts of the object later on. In general, successful later recognition required that the subject actually fixated the part to be recognised. A strategy of thoroughly inspecting the object with a series of closely spaced fixations from only a limited number of viewpoints led to best recognition rates. This was especially true for two subjects trained in fine arts with prior experiences in modelling. The results support models of viewpoint-dependent object recognition with viewer-centred, two-dimensional representations of 3-D objects.

An abundance of p53 null mutations in ovarian carcinoma

Ovarian cancers from 64 midwestern US women were screened for p53 dysfunction both by immunohistochemical staining (IHCS) and single strand conformation polymorphism (SSCP) analysis of the entire open reading frame (ORF). Forty SSCP abnormalities in 39 tumors included nine deletion, one insertion, two splice junction, two nonsense, one silent and 25 missense mutations were confirmed by direct genomic sequencing. Eight of the insertion/deletion defects may have occurred due to slippage during the course of DNA replication. This observation suggests that genomic instability may play an important role in ovarian carcinogenesis. Fifteen percent of the mutations encountered were located outside exons 5-9 and four of these were null. The sensitivity of IHCS was 96% for missense mutations but only 14% for null mutations. This contrasted with 100% sensitivity of the SSCP screening methodology. The 21% overall incidence of null mutations in the present study far exceeds the reported 6.8% incidence in the world literature (P=0.0003). Explanations for this difference include: (1) our complete analysis of the entire ORF of the p53 gene; (2) the tendency of others to rely upon IHCS to screen tumors prior to mutation analysis; and (3) environmental or endogenous genetic influences.

p53 gene mutation analysis and antisense-mediated growth inhibition of human ovarian carcinoma cell lines

Targeting dysfunctional gene expression in the cancer cell with gene-specific therapeutics requires knowledge of the structure and expression of the designated gene. Because of the prevalence of p53 dysfunction in epithelial ovarian carcinoma, modulation of the expression of this tumor suppressor gene is an attractive target for gene therapy. We sequenced the p53 gene and analyzed its expression in 10 ovarian cancer cell lines. Only five cell line mutations were encountered, three associated with a loss of heterozygosity. Thus, neither p53 mutation nor allelic loss is required for ovarian carcinogenesis or propagation of ovarian cancer cell lines in vitro. SSCP screening, but not immunohistochemical staining, correlated with results of direct genomic sequencing. All p53 immunohistochemical-negative cell lines differed from that reported by another laboratory, underscoring the importance of the knowledge of target gene expression in a given cell line in a given laboratory. We designed pilot studies of antisense oligodeoxynucleotides directed against the p53 gene based on our sequence data. Differential growth inhibition of the A2780-CP-20 cell line (mutant p53 protein), but not of the OVCAR-3 cell line (wild-type p53 protein) confirmed the potential usefulness of this strategy.

Absence of significant germ line p53 mutations in ovarian cancer patients

Germ line mutations of the p53 gene have been described in the Li-Fraumeni Cancer Family Syndrome and occur in patients with multifocal gliomas, particularly those with a history of a metachronous cancer or a family history of cancer. p53 dysfunction is often associated with ovarian cancer. Patients with ovarian carcinoma frequently develop synchronous or metachronous cancers and may have a family history of this or related cancers. Thus, we hypothesized that germ line p53 mutations might be associated with a significant proportion of ovarian cancers. Germ line DNA isolated from peripheral leukocytes of 73 patients with ovarian carcinoma was screened for p53 sequence abnormalities utilizing single-strand conformation polymorphism analysis and direct PCR sequencing techniques. As many as 40% of this cohort of ovarian cancer patients from 67 families may represent familial phenotypes. Synchronous and metachronous cancers occurred in 19% of the cohort. Only two intron-based polymorphisms were found. Neither has been previously reported. One of these, in intron 6, occurred in three unrelated patients all of whom had a history of metachronous breast cancer. A polymorphism in intron 10 occurred in a patient with synchronous endometrial cancer. No classic germ line mutations of p53 were found.

Isolation and preliminary characterization of an ovarian carcinoma cell line from a patient with familial ovarian cancer

An epithelial ovarian cancer cell line is established from a patient with recurrent familial ovarian cancer. Two of the patient's sisters and her mother have also had ovarian cancer. The histological resemblance of the cell line to the patient's Stage IV, Grade 3 papillary serous ovarian primary cancer is striking. The cell line does not secrete CA125 and is estrogen and progesterone receptor negative. Overexpression of the p53 tumor suppressor gene but not the HER-2/neu oncogene was detected by immunohistochemical analysis. An unusual chemosensitivity to cisplatin, doxorubicin, etoposide, and taxol is demonstrated, suggesting that a chemosensitivity mechanism might explain prolonged survival of some patients with familial ovarian cancers. This truly unique cell line should prove invaluable in the further evaluation of molecular genetic changes associated with familial ovarian cancers.

Eye movements elicited by transparent stimuli

A transparent motion condition occurs when two different motion vectors appear at the same region of an image. Such transparency during self-motion has shown demonstrable effects on perception and on the underlying neurophysiology in the cortical and subcortical structures of primates. Presumably such stimulus conditions also influence oculomotor behavior. We investigated smooth-pursuit performance, using a transparent stimulus consisting of two oppositely-moving patterns. We found slight reduction in the mean eye velocity tracking a transparent pattern, compared with that when tracking a unidirectional pattern. Additionally, we investigated the behavior of the optokinetic system to transparency, demonstrating that it elicits antagonistic optokinetic nystagmus, with distinctly reduced gain of the slow phases. Furthermore, we observed, during optokinetic stabilization of transparent stimuli, directional dominances demonstrating that subjects preferably followed one direction. Presenting a transparent stimulus with oppositely moving patterns and different velocities we found a general velocity dominance demonstrating that patterns with a certain velocity are preferred. Performing all experiments under dichoptic conditions produced results comparable with those found under transparent stimulus conditions.

Neuropsychological impairment in auto-immune disease

Estimations of the prevalence of central nervous system involvement in patients with systemic lupus erythematosus (SLE) vary from 25 to 75%. In order to assess possible deficits in memory, attention, and/or reaction time, a battery of neuropsychological tests was administered to 15 patients with SLE and to two matched groups of control subjects; eight patients on corticosteroids and 15 healthy controls. The test battery included the Multiple Choice Word Fluency Test (MWT-B), Benton Visual Memory Scale, Syndrome Short Test (SKT; attention and memory), Attention and Concentration Test (d2), Wechsler Adult Intelligence Scale (WAIS) subtests for Comprehension, Digit Span, Block Design, a Computer Controlled Reaction Time task (CCRT), and a Learning and Memory Test (LGT-3). Results revealed a statistically significant short-term memory deficit (for all six relevant subtests used) and a marked delayed simple reaction time in SLE patients as compared with scores in healthy subjects. An attention deficit as well as the expected difference between the estimated premorbid and actual level of intelligence could not be demonstrated. With three exceptions (SKT-9 figural recognition, Benton Visual Memory, and LGT-3 figural recognition), patients treated with corticosteroids did not differ from healthy controls. They also did not differ from SLE patients in any of the parameters tested. It therefore appears that the demonstrated deficit in short-term memory and reaction time in SLE patients may not only be due to the neuropsychiatric manifestation of SLE but possibly also result from medication side-effects.