Primary central nervous system lymphoma: a single-centre experience of 55 unselected cases

AIMS

Current treatment for primary central nervous system lymphoma (PCNSL) involves high-dose methotrexate (HDMTX) with or without radiotherapy. Many published studies describing this approach include a highly selected group of patients. We report a single-centre experience of unselected cases of PCNSL.

MATERIALS AND METHODS

We retrospectively reviewed the case notes of 55 consecutive patients diagnosed with biopsy-proven PCNSL between 1995 and 2003 at Addenbrooke's Hospital Cambridge, UK. We describe the treatment and outcome, including survival, treatment-related toxicity and long-term functional disability.

RESULTS

At diagnosis, 45% of patients were considered unfit to receive treatment with HDMTX, owing to poor performance status or comorbidity. These patients had a median survival of 46 days and may not have been included in other published studies. The remaining patients were treated with a chemotherapy regimen, which included HDMTX. Patients who received at least one cycle of a chemotherapy containing HDMTX had a median survival of 31 months. Forty per cent did not complete planned chemotherapy owing to toxicity, disease progression or death. The median survival of patients treated with HDMTX aged 60 years compared with patients aged under 60 years was 26 months vs 41 months (P = 0.07), respectively. Younger patients treated with HDMTX, who achieved complete remission with chemotherapy, had a median survival of 56 months. We identified a high incidence of functional disability among survivors, resulting from a combination of the tumour itself, the neurosurgical procedure required for diagnosis and the late neurotoxicity of combined chemoradiotherapy.

CONCLUSION

The treatment of PCNSL is associated with significant early and late toxicity. Further attempts to improve treatment should address mechanisms to reduce this toxicity. In particular, the benefit of radiotherapy in patients who achieve complete remission with HDMTX will remain uncertain until it is addressed in a multicentre, randomised trial.

Effect of fluid forcing on vestibular hair bundles

A dynamic 3-D hair bundle model including inertia and viscous fluid drag effects based on the finite element method is presented. Six structural components are used to construct the hair bundle--kinocilium, stereocilia, upper lateral links, shaft links, tip links, and kinocilial links. Fluid drag is distributed on the surface of cilia columns. Bundle mechanics are analyzed under two distinct loading conditions: (1) drag caused by the shear flow of the surrounding endolymph fluid (fluid-forced), (2) a single force applied to the tip of the kinocilium (point-forced). A striolar and a medial extrastriolar vestibular hair cell from the utricle of a turtle are simulated. The striolar cell bundle shows a clear difference in tip link tension profile between fluid-forced and point-forced cases. When the striolar cell is fluid forced, it shows more evenly distributed tip link tensions and is far more sensitive, responding like an on/off switch. The extrastriolar cell does not show noticeable differences between the forcing types. For both forcing conditions, the extrastriolar cell responds serially--the nearest tip links to the kinocilium get tensed first, then the tension propagates to the farther tip links.

Reducing medication errors in the neonatal intensive care unit

BACKGROUND

Medication errors are common in the neonatal intensive care unit (NICU). Various strategies to reduce errors have been described in adult and paediatric patients but there are few published data on their effect in the NICU.

AIM

To describe the medication errors occurring within an NICU, and assess the impact of a combined risk management/clinical pharmacist led education programme on these errors.

METHODS

Medication errors were identified prospectively over one year by critical incident reporting. Four months into the study, a pharmacist led education programme was instituted. This involved a daily, cot side, pharmacist led review of medication orders. Each new member of pharmacy, nursing, or medical staff was also required to successfully complete a series of dose calculations. In addition, a risk management approach was used to make several changes in practice during the study period.

RESULTS

A total of 105 errors were identified, four serious, 45 potentially serious, and 56 minor. The four serious errors included two tenfold dose miscalculations. Most (71%) of the errors were due to poor prescribing. After the introduction of our interventions, monthly medication errors fell from a mean (SD) of 24.1 (1.7) per 1000 neonatal activity days to 5.1 (3.6) per 1000 days (p < 0.001) in the following three months. The subsequent change over of junior medical staff was associated with a significant increase in medication errors to 12.2 (3.6) per 1000 neonatal activity days (p = 0.037). However, the number remained significantly less than before our interventions (p < 0.001). Three serious errors occurred in the first four months compared with one in the second eight month period, the latter corresponding to the six monthly change over of junior medical staff.

CONCLUSIONS

Medication errors are common in NICUs. Fortunately, actual harm to an infant is rare. Interventions to reduce errors, particularly within the context of a risk management programme, are effective.

Basaltic rocks analyzed by the Spirit Rover in Gusev Crater

The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain </=25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mössbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.

Surgical management of incompletely excised basal cell carcinomas of the head and neck

We made a retrospective audit of all basal cell carcinomas excised in the Maxillofacial Units at St. Richard's Hospital, Chichester and the Worthing and Southlands NHS Trust between 1990 and 1999. A total of 3795 BCCs were excised. Of these, 3560 were completely excised (93.8%) and 235 were incompletely excised (6.2%), which compares favourably with other series. Of these, 84 patients had further excision, 11 had radiotherapy, and 140 were kept under review. Residual tumour was present in 45% of the re-excised specimens. Of the 140 cases managed by observation, 21% recurred. Notably, 31% of patients in the observation cohort died of other causes without recurrence. Incomplete excision was significantly more likely (P < 0.001) if multiple lesions were excised at the time of operation. Involvement of multiple margins was not a significant risk factor for recurrence in the 'observed' cohort. This study shows that a flexible strategy, which balances observation, further excision and radiotherapy, is superior to any single approach.

Aberrant expression of minichromosome maintenance protein-2 and Ki67 in laryngeal squamous epithelial lesions

Histological classification of laryngeal epithelial lesions is highly subjective, and methods of cytological detection are not well developed. Improved determination of aberrant cell cycle entry may allow increased objectivity in histological assessment and enable the development of less invasive diagnostic cytology tests. Sections of normal larynx (n=10), laryngeal dysplasia (n=20) and laryngeal squamous cell carcinoma (SCC) (n=10) were classified according to the Ljubljana classification and stained for markers of cell cycle entry, minichromosome maintenance protein-2 (Mcm-2) and Ki67. Expression patterns were compared using double labelling confocal microscopy. There was a correlation between Mcm-2 and Ki67 labelling indices (rho=0.93; 95% CI [0.84, 0.97]) and both markers showed increased expression from normal epithelium to SCC (Mcm-2, P=0.001; Ki67, P=0.0002). Importantly, there was minimal expression of Mcm-2 or Ki67 in the most superficial layers of normal larynx and abnormal or atypical hyperplasia, in contrast to carcinoma in situ and SCC. Clusters of Mcm-2/5-positive cells were present in cytological preparations from SCC, but not from those showing atypical hyperplasia or inflammation in non-neoplastic tissue. Minichromosome maintenance protein-2 staining may increase the objectivity and reliability of histological grading of laryngeal epithelial lesions. Laryngeal brushings, combined with immuno-enhanced liquid-based cytology, could be useful, as a less invasive approach, to the detection of laryngeal malignant and premalignant lesions.

[A pilot community study of subjective memory in over and under 65 years old]

Elderly adults are appropriate targets for objective memory assessment and cognitive testing in the promotion of earlier recognition of people with symptoms of a dementing process. The major change in memory with age is the decline in ability to recall things explicitly. There is a need for education of the general public and health professionals about memory impairment and its relationship with stress, depression, anxiety and dementia.

Covictimization and inner city youth: a review

Covictimization represents a real and present danger to inner city youth. This paper reviews the scope of this problem and a potential emergency mental health response.

In vitro studies indicate that acid catalysed generation of N-nitrosocompounds from dietary nitrate will be maximal at the gastro-oesophageal junction and cardia

BACKGROUND

Dietary nitrate increases saliva nitrite levels and swallowed saliva is the main source of nitrite entering the acidic stomach. In acidic gastric juice, this nitrite can generate potentially carcinogenic N-nitrosocompounds. However, ascorbic acid secreted by the gastric mucosa can prevent nitrosation by converting the nitrite to nitric oxide.

METHODS

To study the potential for N-nitrosocompound formation in a model simulating salivary nitrite entering the acidic stomach and the ability of ascorbic acid to inhibit the process. Concentrations of ascorbic acid, total vitamin C, nitrite, nitrosomorpholine, oxygen and nitric oxide were monitored during the experiments.

RESULTS

The delivery of nitrite into HCl containing thiocyanate resulted in nitrosation of morpholine, with the rate of nitrosation being greatest at pH 2.5. Under anaerobic conditions, ascorbic acid converted the nitrite to nitric oxide and prevented nitrosation. However, in the presence of dissolved air, the ascorbic acid was ineffective at preventing nitrosation. This was due to the nitric oxide combining with oxygen to reform nitrite and this recycling of nitrite depleting the available ascorbic acid. Further studies indicated that the rate of consumption of ascorbic acid by nitrite added to natural human gastric juice (pH 1.5) was extremely rapid with 200 micromol/l nitrite consumed 500 micromol/l ascorbic acid within 10 s.

CONCLUSIONS

The rapid consumption of ascorbic acid in acidic gastric juice by nitrite in swallowed saliva indicates that the potential for acid nitrosation will be maximal at the GO junction and cardia where nitrite first encounters acidic gastric juice. The high incidence of mutagenesis and neoplasia at this anatomical location may be due to acid nitrosation arising from dietary nitrate.

Wheat germ supplement reduces cyst and trophozoite passage in people with giardiasis

The protozoan parasite Giardia lamblia is a major cause of waterborne enteric disease worldwide. Lectins are proteins that bind to carbohydrate (sugar) moieties. Potential targets for lectins are found on the surface of most single-celled organisms. Modest concentrations of wheat germ agglutinin (WGA) have been shown to inhibit G. lamblia excystation and trophozoite growth in vitro and can reduce cyst passage in mice infected with the closely related protozoan parasite, G. muris. Commercial preparations of wheat germ (WG) contain 13-53 microg of WGA per gram. We performed a double-masked, placebo-controlled study of dietary supplementation with WG in 63 subjects with giardiasis in Montreal and Lima (25 asymptomatic patients passing cysts; 38 patients with symptoms). Asymptomatic subjects received WG (2 g, 3 times a day) or placebo (cornstarch, 2 g, 3 times a day) for 10 days, followed by metronidazole (250 mg 3 times a day) for 7 days. Symptomatic subjects received metronidazole (250 mg 3 times a day) plus either WG or placebo for 7 days. Stool specimens were collected every day (Montreal) or every other day (Lima) for 10 days and on Day 35 for microscopic examination and coproantigen determination. Subjects kept a diary of symptoms for 10 days after recruitment. In asymptomatic subjects, both cyst passage and coproantigen levels were reduced by approximately 50% in those taking WG compared with the placebo group (P < 0.01 and P = 0.06, respectively). In symptomatic subjects, cyst passage and coproantigen levels fell precipitously in response to metronidazole therapy, and there were no clinically important differences between those receiving supplemental WG or placebo. However, symptoms appear to have resolved more rapidly in the subjects taking WG in addition to metronidazole. The WG supplement was well tolerated in both symptomatic and asymptomatic subjects. These data suggest that components of WG, possibly WGA, either alone or in combination with antiprotozoal agents, can influence the course of human giardiasis.

Surgical and nonpsychiatric medical treatment of patients with body dysmorphic disorder

It appears that many individuals with body dysmorphic disorder (BDD) receive nonpsychiatric medical treatment and surgery; however, this topic has had little systematic investigation. This study assessed the nonpsychiatric treatment sought and received by 289 individuals (250 adults and 39 children/adolescents) with DSM-IV BDD. Such treatment was sought by 76.4% and received by 66.0% of adults. Dermatologic treatment was most often received (by 45.2% of adults), followed by surgery (by 23.2%). These treatments rarely improved BDD symptoms. Results were similar in children/adolescents. These findings indicate that a majority of patients with BDD receive nonpsychiatric treatment but tend to respond poorly.

Genetic correlation between the P300 event-related brain potential and the EEG power spectrum

Previous studies have demonstrated moderate heritability of the P300 component of event-related brain potentials (ERPs) and high heritability of background electroencephalogram (EEG) power spectrum. However, it is unclear whether EEG and ERPs are influenced by common or independent genetic factors. This study examined phenotypic and genetic correlations between EEG spectral power and P300 amplitude using data from 206 Dutch twin pairs, age 16 years. Multivariate genetic models (Cholesky decomposition) were fitted to the observed twin covariances using Mx software. In males, genetic correlations between P300 and EEG power measures were high (0.54-0.74); 30% of the total P300 variance could be explained by genetic factors influencing EEG delta power and 26% by P300-specific genetic factors (total heritability 56%). In females, 45% of P300 variance could be attributed to familial influences that were shared with the EEG. However, it was not possible to distinguish between the genetic versus shared environmental factors, consistent with previous analysis of P300 in this sample (van Beijsterveldt et al., 1998). The results suggest that a substantial proportion of genetic influences on P300 amplitude can be explained by strong heritability of slow EEG rhythms contributing to P300.

Learning to read in Williams syndrome: looking beneath the surface of atypical reading development

In this paper, we make a fundamental distinction between literacy attainment scores and the actual process of learning to read, and examine these two aspects of reading in atypical development. Reading skills in a group of children and adults with the genetic disorder Williams syndrome (WS) were compared to a group of typically developing children matched for reading age and receptive vocabulary scores. Study 1 focused on the product of reading and explored the relationship between reading, general cognition, and phonological skills. Phonological skills were shown to be related to individual differences in reading attainment in both groups, although more weakly in the WS group. Experiment 2 examined the process of learning to read. The two groups were taught to associate abbreviated spellings (cues) with spoken words. The cues differed in their phonetic closeness to the target words, whereas the target words differed on the semantic variable of imageability. Compared to controls, the WS group showed slower learning, less sensitivity to the phonetic quality of the cue, and reduced influence from the imageability of words. The results support the hypothesis that although reading levels in WS depend on phonological skills, the full development of their reading is compromised by weak semantics. The studies highlight the importance in atypical populations of examining both reading levels and the actual process of learning to read.

International gastroenterology research: subject areas, impact, and funding

AIMS

To examine the volume and potential impact of gastroenterology research outputs from 1985 to 1998 from 14 developed countries; the overlap with research in cancer, infectious diseases, and genetics; and the funding sources for this research. To determine if countries' research outputs correlated with their burden of corresponding diseases and inputs to their research.

METHODS

Selective retrieval of papers from the Science Citation Index and manual look up of a sample to determine funding sources. Classification of journals by four categories of research level (clinical/basic) and potential impact (low/high).

RESULTS

Gastroenterology represents about 8% of world biomedical research but over 11% in Italy, Japan, and Spain. Its potential impact is highest (but declining) for the USA. It has increased noticeably in most European countries, particularly in Finland. Gastroenterology research has become more clinical in Japan, Spain, Australia, and the Netherlands but more basic in Canada, Germany, Finland, Israel, and South Africa. Funding comes primarily from national governments, followed by national private non-profit sources and industry but little industrial funding occurs in some countries. There is a strong and positive correlation between reported deaths from gastrointestinal neoplasms and countries' outputs of research in gastrointestinal oncology.

CONCLUSIONS

Bibliometric analysis can reveal differences between countries in their research in a subject when a common methodology is applied to an international database. Variations in research methods in different countries can plausibly explain some of the variation in the potential impact of the work.

Effect of acute exposure to ammonia on glutamate transport in glial cells isolated from the salamander retina

A rise of brain ammonia level, as occurs in liver failure, initially increases glutamate accumulation in neurons and glial cells. We investigated the effect of acute exposure to ammonia on glutamate transporter currents in whole cell clamped glial cells from the salamander retina. Ammonia potentiated the current evoked by a saturating concentration of L-glutamate, and decreased the apparent affinity of the transporter for glutamate. The potentiation had a Michaelis-Menten dependence on ammonia concentration, with a K(m) of 1.4 mM and a maximum potentiation of 31%. Ammonia also potentiated the transporter current produced by D-aspartate. Potentiation of the glutamate transport current was seen even with glutamine synthetase inhibited, so ammonia does not act by speeding glutamine synthesis, contrary to a suggestion in the literature. The potentiation was unchanged in the absence of Cl(-) ions, showing that it is not an effect on the anion current gated by the glutamate transporter. Ammonium ions were unable to substitute for Na+ in driving glutamate transport. Although they can partially substitute for K+ at the cation counter-transport site of the transporter, their occupancy of these sites would produce a potentiation of < 1%. Ammonium, and the weak bases methylamine and trimethylamine, increased the intracellular pH by similar amounts, and intracellular alkalinization is known to increase glutamate uptake. Methylamine and trimethylamine potentiated the uptake current by the amount expected from the known pH dependence of uptake, but ammonia gave a potentiation that was larger than could be explained by the pH change, and some potentiation of uptake by ammonia was still seen when the internal pH was 8.8, at which pH further alkalinization does not increase uptake. These data suggest that ammonia speeds glutamate uptake both by increasing cytoplasmic pH and by a separate effect on the glutamate transporter. Approximately two-thirds of the speeding is due to the pH change.

Spread of a recurrent lentigo maligna into a graft: a case for conservative treatment

Lentigo maligna is an in situ malignant melanoma for which the treatment of choice is surgical excision. The recurrence rate in lentigo maligna is high and hence other treatments, such as cryotherapy, laser therapy, radiotherapy and Mohs' chemosurgery, have been described. Despite the high recurrence rate, spread of a lentigo maligna into a skin graft is rare. We describe a case of a recurrent lentigo maligna spreading into a skin graft, which, along with the cases described in the literature, highlights the presence of a group of low-grade malignant lentiginous lesions that may be managed by careful follow-up and observation.

Influence of an interdental full pin on stability of an acrylic external fixator for rostral mandibular fractures in dogs

OBJECTIVE

To determine total stiffness and gap stiffness of an external fixation system in a canine mandibular fracture gap model incorporating a full interdental pin as the only point of rostral fixation in a bilateral type-I external fixator.

SAMPLE POPULATION

10 canine mandibles.

PROCEDURE

Bilateral mandibular ostectomies were performed between premolars 3 and 4. A type-I external fixator incorporating a full interdental pin was placed to stabilize a 0.5-cm fracture gap. Four pin configurations (intact mandibular bodies with fixator; ostectomized mandibular bodies and complete fixator; ostectomized mandibular bodies with caudal pins of rostral fragment cut; ostectomized mandibular bodies with all pins of rostral fragment cut) were tested in dorsoventral bending 5 times on each mandible. The full interdental pin remained intact in all configurations. Total stiffness and gap stiffness were determined for each configuration on a materials testing machine.

RESULTS

Total stiffness of intact mandibles was significantly greater than that of ostectomized mandibles, regardless of external fixator configuration. However, total stiffness and gap stiffness were not significantly different among different external fixator configurations applied to ostectomized mandibles.

CONCLUSION AND CLINICAL RELEVANCE

External fixator configurations with only the full interdental pin engaging the rostral fragment were as stiff as configurations that had 2 or 4 additional pins in the rostral fragment for the applied loads. External fixators for rostral mandibular fractures may be rigidly secured with rostral fragment implants applied extracortically, avoiding iatrogenic trauma to teeth and tooth roots.