Audit of an inpatient neurology consultation service in a tertiary referral centre: value of the consulting neurologist

The Mater Misericordiae Hospital is a 575-bed tertiary referral centre with busy medical and surgical subspecialty services (including the national cardiac, cardiothoracic, spinal cord injury and pulmonary hypertension units). An audit of in-patient referrals to a neurology service was carried out over the twelve-month period of January to December 2002 inclusively. Five hundred and seventy seven inpatients were evaluated and managed in conjunction with the referring services. Consultation by the neurological service led to a significant contribution in the management of clinical cases in one of three ways: establishing a de novo diagnosis in patients admitted with active neurological symptoms where no working diagnosis exists (40.7% of referrals), significant alteration in diagnosis where the referring service have already established a specific working diagnosis (11.1% of referrals), or offering advice in the ongoing management of active neurological symptoms when the diagnosis is historically established and secure (48.2% of referrals). In order of frequency the most common reason for referral was stroke (131 cases (22.7%)), seizures unrelated to alcohol (59 cases (10.2%)), alcohol-related neurological problems (55 cases (9.5%)), movement disorders (41 cases (7.1%)), neuromuscular (40 cases (6.9%)), coma (35 cases (6%)), disorders of cognition (31 cases (5.3%)), acute headache (28 case (4.8%)) and functional neurological syndromes (26 cases (4.5%)). This audit highlights the value of a consulting neurology service in a multidisciplinary tertiary referral setting.

Escalated median dose for pituitary macroadenomas using intensity-modulated radiation therapy

Three-dimensional conformal radiotherapy (3D CRT) has become an established treatment for pituitary macroadenomas. This study is an investigation into the possible dosimetric advantages of intensity-modulated radiotherapy for such critically located tumors. Three consecutive patients with pituitary macroadenoma previously treated with 3D CRT were replanned with inverse-planned IMRT using Helax-TMS (V.6.0, Helax AB, Uppsala, Sweden. Fusion of computed tomography (CT) with postoperative magnetic resonance imaging (MRI) was performed within the planning system to define the gross tumor volume (GTV), planning target volume (PTV), and normal structures including the optic chiasm. Dose-volume histograms (DVHs) for the 3D CRT plans were then compared with those of the corresponding prospective IMRT plans. Both techniques maintained critical structure doses below tolerance levels while maintaining a minimum dose of 45 Gy to 100% of the PTV. While IMRT plans deliver consistently more heterogeneous dose distributions to the PTV, the median PTV dose is elevated in the IMRT plans compared with the 3D CRT plans. For critically located tumors like these pituitary macroadenomas, IMRT allows escalation of the median dose to the tumor without an accompanying loss in critical structure sparing or creating unacceptable cold spots within the PTV.

A study of metabolites as intermediate effectors in angiogenesis

Metabolites released from hypoxic tissues have been reported as angiogenic factors in circumstances of reduced tissue oxygenation or an increased rate of metabolism. However, in more recent reports their possible role in angiogenesis prior to the induction of hypoxia-inducible genes appears to have been neglected. In a systematic attempt to evalaute their role, metabolites common to the glycolytic and oxidative pathways (nicotinamide adenine dinucleotide, adenosine diphosphate and adenosine triphosphate), exclusively glycolytic metabolites (pyruvate and lactic acid) and exclusively oxidative metabolites (malate, succinate, fumarate and citrate) were tested to assess their effects upon in vivo angiogenesis and in vitro endothelial cell migration and proliferation. In addition, adenosine was tested due to its proposed role in hypoxia-induced angiogenesis. The angiogenic effects in vivo were examined using the chick chorioallantoic membrane assay and in vitro on chick embryonic capillary endothelial cells using a phagokinetic track/migration assay and crystal violet dye binding/proliferation assay. Metabolites common to the glycolytic and oxidative metabolic pathways and exclusively glycolytic metabolites produced an angiogenic response in vivo and in vitro on endothelial cell proliferation and migration, whereas exclusively oxidative metabolites, with the exception of malate, did not. Adenosine caused an increased proliferation of blood vessels in vivo and stimulated endothelial cell migration and proliferation. Overall, these results implicate metabolites as effectors in angiogenesis and it is proposed that they have a role which is possibly independent of the upregulation of hypoxia-inducible genes.

Dosimetric verification of inverse planned step and shoot multileaf collimator fields from a commercial treatment planning system

An inverse treatment planning (ITP) module on a commercial treatment planning system (TPS) (Helax AB, Uppsala, Sweden) is being used for an in-house clinical trial for treatment of nasopharyngeal cancer with contralateral parotid sparing. Intensity modulated radiation therapy (IMRT) fields are delivered by step and shoot multileaf collimator (MLC) with a DMLC enabled Varian 2300 CD (Varian Associates, Palo Alto, CA). A series of testing procedures have been devised to quantify the modeling and delivery accuracy of routine clinical inverse planned IMRT using Helax TMS and the Varian step and shoot MLC delivery option. Testing was done on specific aspects of the TPS modeling germane to DMLC. Measured relative dose factors (head scatter plus phantom scatter) for small MLC fields, normalized to a 10x10 cm2 non-MLC field, were found to differ by 2-3% from the TPS values for the smallest of the fields tested. Relative distributions for small off axis fields were found to be in good agreement. A process for the routine clinical verification of IMRT fields has been implemented. Each IMRT field in an inverse plan is imported into a flat water tank plan and a "beam's eye view" (BEV) dose distribution is generated. This is compared to the corresponding measured BEV dose distribution. The IMRT verification process has also been performed using an anthropomorphic phantom. Large clinical fields (i.e., greater than 14.5 cm in the leaf direction) caused difficulties due to a vendor specific machine restriction, and several techniques for dealing with these were examined. These techniques were (i) the use of static stepping of closed junctions, (ii) the use of two separate IMRT fields for a given gantry angle, and (iii) restricting the overall maximum field size used. The overall process has allowed implementation of an in-house protocol for IMRT use on an initial clinical site. Results of the verification measurements for the first ten patients treated at this center reveal an average maximum dose per IMRT field delivered of 71.0 cGy, with a mean local deviation from the planned dose of -1.2 cGy, and a standard deviation of 2.4 cGy.

Ganciclovir pharmacokinetics and cytokine dynamics in renal transplant recipients with cytomegalovirus infection

Ganciclovir is considered to be the first-line treatment for cytomegalovirus (CMV) in renal transplant recipients. This infection is also associated with elevations of specific plasma cytokines post-transplantation. To investigate daily cytokine response to therapy and ganciclovir pharmacokinetics, 4 transplant recipients (3 males, 1 female) with stable renal allograft function diagnosed with CMV infection were enrolled less than 4 months post-transplant. A creatinine clearance (ClCr) was generated by the Cockroft-Gault (C-G) equation (range: 42.3-68.5 mL/min) to determine ganciclovir dosing. Blood samples were collected for ganciclovir and cytokine [including interleukin (IL)-1beta, IL-2, IL-3, IL-4, IL-6, IL-8, IL-10, TNF-alpha, GM-CSF, and interferon (IFN)-gamma analyses after 7 d of intravenous (i.v.) ganciclovir (dosage range: 165-400 mg daily) therapy and again after 7 d of oral (p.o.) ganciclovir (dosage range: 1000 mg, 2-3 times daily) therapy. Pharmacokinetic ganciclovir was described with a two-compartment model. Total clearance of ganciclovir was consistently greater than ClCr, suggesting tubular secretion. Peak concentrations for i.v. ganciclovir averaged 8.39+/-1.87 microg/mL with minimum concentrations of 0.48+/-0.35 microg/mL. Plasma concentrations were lower but more sustained during a p.o. dosing interval (max=2.12+/-0.58 microg/mL, min=1.15+/-0.34 microg/mL). IL-6, IL-8, IL-10, and TNF-alpha were detectable at multiple times during the study periods while the remainder of the cytokines were only intermittently detectable. Average concentrations (i.v. versus p.o. study period) for TNF-alpha were 40.1+/-17.5 versus 22.1+/-11.2 pg/mL, for IL-8 were 17.1+/-15.6 versus 4.12+/-2.59 pg/mL, and for IL-10 were 7.39+/-5.54 versus 2.64+/-1.06 pg/mL. Concentrations were similar for IL-6 during both studies (9.39+/-5.42 versus 14.7+/-14.8 pg/mL). TNF-alpha, IL-8, and IFN-gamma appeared to correlate with CMV antigenemia. Further investigation of ganciclovir disposition and changes in plasma cytokines in renal transplant recipients during CMV infection may provide insight into variable antiviral responses in renal transplant recipients.

An exploration of evolved mental mechanisms for dominant and subordinate behaviour in relation to auditory hallucinations in schizophrenia and critical thoughts in depression

BACKGROUND

Mental mechanisms have evolved to enable animals (and humans) to be able to function in various social roles. It is suggested that the nature and functions of the mental mechanisms that enable animals to act as a hostile-dominant or threatened-subordinate can be distinguished. It is further suggested these can be internally activated and 'play off' against each other, such that a person 'attacks' themselves and then responds to their own internal attacks with subordinate defences. Hence, a depressed person can submit, feel defeated, belittled, beaten down, or want to run away (escape) from their own self-attacking thoughts, while psychotic voice hearers can feel similarly to their hostile voices. Such internal interactions may relate to depression in both psychotic voice hearers and depressed people.

METHOD

A group of 66 voice hearers with a diagnosis of schizophrenia and 50 depressed patients were compared on a series of self-report questionnaires measuring the power of hostile self-directed thoughts/voices and the activation of defensive responses, especially fight/flight.

RESULTS

We present evidence that schizophrenic, malevolent voice hearers and self-critical depressed people experience their hostile, internally generated voices/thoughts as powerful, dominating and controlling (i.e. have typical characteristics of a hostile dominant). Moreover, these voices/thoughts activate evolved subordinate defences such as fight/flight and these are associated with depression in both depression and schizophrenia.

CONCLUSION

Conceptualizing aspects of depressed and psychotic thinking as relating to evolved mental mechanisms, which are role serving, but can internally play off against each other, may open new ways of investigating certain aspects of severe pathologies.

Deliberate self poisoning with antidepressant drugs: a comparison of the relative hospital costs of cases of overdose of tricyclics with those of selective-serotonin re-uptake inhibitors

BACKGROUND

Debate continues over the relative merits of tricyclics and selective serotonin re-uptake inhibitors (SSRIs) as first line antidepressant treatment for depression. SSRIs are safer in overdose but more expensive than tricyclics. This report compared the hospital costs of cases of overdose with both groups of drug.

METHODS

Records of all persons aged over thirteen years presenting to a general hospital in one year were analysed for demographic information and details of their attendance.

RESULTS

There were 1165 episodes of self-poisoning, 151 involving tricyclics as the sole antidepressant and 69 SSRIs as the sole antidepressant. Those taking SSRIs had a shorter (1.96 vs. 2.59 days) and less expensive ( pound330 vs. pound567) stay. A large proportion of this difference in cost was due to a small number of admissions to the Intensive Care Unit.

LIMITATIONS

This study used only hospital costs, so excluding costs associated with primary care.

CONCLUSIONS AND CLINICAL RELEVANCE

If there were similar cost differences countrywide, the difference in hospital costs of self poisoning with SSRIs and tricyclics would represent an additional pound3.87 million per year due to self poisoning with tricyclics across the whole of England and Wales. This is a small proportion of the estimated pound100 million cost of switching to first-line prescribing of SSRIs for depression.

Masseter and temporalis muscle EMG levels and bite force in migraineurs

The purpose of this study was to compare absolute and proportional electromyography (EMG) levels in the masseter and temporalis muscles during performance of a variety of oral functions for migraineurs and age- and sex-matched controls. Both groups consisted of nine women and one man, with a mean age of 43 years (range, 29 to 51 years). Absolute resting EMG levels and those levels during swallowing and speech were not significantly different between the groups, but the levels of the group with migraine were significantly higher during maximum voluntary effort contractions on the anterior teeth and on the posterior teeth for both muscles. When expressed as a percentage of those levels obtained at maximal posterior contraction (ie, proportional levels), no difference in functional activity was demonstrated between groups. It was concluded that the two groups studied had similar levels of EMG activity in the masseter and temporalis muscles during the normal oral functions investigated, but that the group with migraine had higher levels of absolute EMG activity during anterior and posterior maximum voluntary contractions. Furthermore, the group with migraine demonstrated higher levels of anterior and posterior bite force, although not correlated with EMG levels.

Evidence that the reactivity of the martian soil is due to superoxide ions

The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.

Intracoronary blood sampling using the multifunction probing catheter does not cause platelet activation

We sought to test the hypothesis that intracoronary blood sampling in patients with angiographically demonstrated coronary artery disease could be performed using the multifunction probing catheter (Schneider, Bulach, Switzerland), without causing ex vivo platelet activation.

Lupus anticoagulants form immune complexes with prothrombin and phospholipid that can augment thrombin production in flow

Lupus anticoagulants (LA) are a family of autoantibodies that are associated with in vitro anticoagulant activity but a strong predisposition to in vivo thrombosis. They are directed against plasma phospholipid binding proteins, including prothrombin. We found that a murine monoclonal antiprothrombin antibody and 7 of 7 LA IgGs tested enhanced binding of prothrombin to 25:75 phosphatidyl serine:phosphatidyl choline vesicles in a concentration-dependent manner. We hypothesized that enhanced binding of prothrombin to phospholipid in the presence of LA IgG might result in increased thrombin production when reactions are performed in flow. Thrombin production by purified prothrombinase components was measured in a phospholipid-coated flow reactor. The flow reactor was incubated with prothrombin, calcium ions, and the IgGs and then perfused with prothrombin, calcium ions, the IgGs, factor Va, and factor Xa. A murine monoclonal antiprothrombin antibody and 4 of 6 LA IgGs from patients with a history of thrombosis increased thrombin production up to 100% over control in the first 15 minutes. In summary, LA IgGs concentrate prothrombin on a phospholipid surface that can augment thrombin production by prothrombinase in flow. These observations suggest that LA might propagate coagulation in flowing blood by facilitating prothrombin interaction with the damaged blood vessel wall.

The development of target-eye-view maps for selection of coplanar or noncoplanar beams in conformal radiotherapy treatment planning

Three-dimensional conformal radiotherapy allows the use of tightly conformed, multiple coplanar or noncoplanar beams. However, visualizing the spatial relationships between the target volume and adjacent critical structures is not always obvious or intuitive. Tools such as beam's eye view (BEV) have aided in this process and been very useful. In this study, a target-eye-view (TEV) map is developed as a functional extension of BEVs. The TEV map for a critical structure is created by checking the BEVs for all gantries and table rotations. For each possible BEV, the amount of overlap between the planning target volume (PTV) and the organ at risk (OAR) is determined. This information is presented in a Mercator spherical map, where the color tone indicates the amount of overlap between the PTV and the OAR. A composite TEV map is then created by summing the TEV grading scores for all OARs. The composite map shows beam orientations with the most overlap being light and the least overlap being dark, thus simplifying the selection of appropriate beam angles. The accuracy of the TEV maps has been confirmed separately with corresponding BEVs generated by a three-dimensional treatment planning system.

Direct measurement of recombination frequency in interspecific hybrids between Hordeum vulgare and H. bulbosum using genomic in situ hybridization

Two different genotypes of diploid Hordeum vulgare x H. bulbosum hybrids, which differ in their pattern of meiotic metaphase pairing behaviour, were investigated at MI and AI by genomic in situ hybridization (GISH). One hybrid, 102C2, showed a high frequency of bivalents at metaphase I whereas the other, 103K5, showed a high frequency of univalents. The GISH analysis of both hybrids established that pairing occurred only between chromosomes of different parental genomes and revealed that pairing frequency greatly exceeded recombination. Hybrid 102C2 had a significantly higher recombination frequency than 103K5, but in both hybrids recombination involved only distal chromosome regions. However, an interesting finding is that the ratio of recombination to pairing frequency in 103K5 (1:8.9) is twice as high compared with 102C2 (1:17). The hybrids also differed in chromosome stability; little chromosome elimination occurred in 102C2 but 103K5 showed extensive chromosome loss. It appears that the high frequency of bound arms at MI favours retention of H. bulbosum chromosomes and maintains stability of chromosome numbers in PMCs. Various ideas are put forward to explain the discrepancy between meiotic pairing frequency and recombination in these hybrids.

Effectiveness of nurse executives: measurement of role factors and attitudes

This article describes the outcome of a survey of 40 nurse executives and 56 influential colleagues. Both groups agreed that leadership was the most important quality for the executive role. The nurses' primary focus was resolution of patient care problems. Influential colleagues stated resource allocation and initiation of change were two qualities needing improvement. The nurses rated themselves high in confidence about their job responsibilities, scored relationships as the most satisfying attribute, and cited provision of quality health care as the greatest advantage of their position. The greatest disadvantage was lack of administrative support. The results suggest the educational preparation needed for nurse executives.

Expression, purification and immunological characterization of the transforming protein E7, from cervical cancer-associated human papillomavirus type 16

E7 is the major oncogenic protein produced in cervical cancer-associated human papillomavirus type 16 (HPV16). This protein was expressed in Escherichia coli as a glutathione-S-transferase (GST) fusion protein. E7-enriched inclusion bodies were collected from bacterial lysates, were solubilized in 10 M urea, and the protein was purified using anion exchange column chromatography. After removal of endotoxin with serial Triton X-114 extractions, material of high purity (about 90%) was obtained, which is suitable for use in a human clinical trial. This material was immunogenic, and when used as a vaccine, protected mice against challenge with an HPV16 E7 DNA transfected tumour cell line. Based on this observation, the E7GST fusion protein is currently being used in a human clinical trial of a vaccine against HPV16-induced cervical cancer. This fusion protein could be cleaved with thrombin to remove the GST fusion part and further purified by preparative SDS gel electrophoresis to obtain free E7 with > 98% purity.

Implantation metastasis of primary central nervous system lymphoma complicating radiotherapy outcome

Computed tomography-guided stereotactic biopsy is commonly used in the diagnosis of brain lesions. An uncommonly reported risk of the procedure is the potential of implantation metastasis. This phenomenon has been reported in central nervous system malignancies. Although the role of prophylactic local radiotherapy at biopsy sites is well recognized in solid tumors, it has not been reported to occur after stereotactic biopsy of a brain tumor. The authors report a case of locally progressive primary central nervous system lymphoma at an unsuspiciously underdosed biopsy site complicating radiotherapy outcome.

Setup reproducibility in radiation therapy for lung cancer: a comparison between T-bar and expanded foam immobilization devices

PURPOSE

Physiologic and non-physiologic tumor motion complicates the use of tight margins in three-dimensional (3D) conformal radiotherapy. Setup reproducibility is an important non-physiologic cause of tumor motion. The objective of this study is to evaluate and compare patient setup reproducibility using the reusable T-bar and the disposable expanded foam immobilization device (EFID) in radiation therapy for lung cancer.

METHODS AND MATERIALS

Two hundred forty-four portal films were taken from 16 prospectively accrued patients treated for lung cancer. Patients were treated with either a pair of anterior and posterior parallel opposing fields (POF), or a combination of POF and a three-field isocentric technique. Each patient was treated in a supine position using either the T-bar setup or EFID. Six patients were treated in both devices over their treatment courses. Field placement analysis was used to evaluate 3D setup reproducibility, by comparing positions of bony landmarks relative to the radiation field edges in digitized simulator and portal images. Anterior-posterior, lateral, and longitudinal displacements, as well as field rotations along coronal and sagittal planes were measured. Statistical analyses of variance were applied to the deviations among portal films of all patients and the subgroup treated with both immobilization methods.

RESULTS

For the T-bar immobilization device, standard deviations of the setup reproducibility were 5.1, 3.7, and 5.1 mm in the anterior-posterior, lateral, and longitudinal dimensions, respectively. Rotations in the coronal plane and the sagittal plane were 0.9 degrees and 1.0 degrees, respectively. For the EFID, corresponding standard deviations of set up reproducibility were 3.6 mm, 5.3 mm, 5.4 mm, 0.7 degrees and 1.4 degrees, respectively. There was no statistically significant difference (p = 0.22) in the 3D setup reproducibility between T-bar and EFID. Subgroup analysis for the patients who were treated with both immobilization devices did not reveal a difference either. There was no consistent systematic error from simulator to treatment unit identified for either immobilization device.

CONCLUSION

Although the optimal immobilization technique and patient positioning for thoracic radiotherapy have yet to be determined, this study indicates that T-bar is comparable with EFID in its setup reproducibility. In view of the inherent advantages of T-bar, it has become a standard immobilization device at our institution. The observed range of displacements in field positioning with either immobilization device implies that one cm (two standard deviations [SD] of setup error) will be a more appropriate margin to allow for setup variability in radiation therapy for lung cancer.

An audit of pancreatic pseudocyst management and the role of endoscopic pancreatography

BACKGROUND

A rational algorithm for the management of symptomatic pancreatic pseudocysts is necessary with the increasing availability of radiological, surgical and endoscopic methods of treatment.

METHODS

A retrospective audit of the management and outcome of all patients who presented with symptomatic pancreatic pseudocysts to the Auckland Hospital over a 9-year period (1988-96) was made.

RESULTS

There were 44 patients (28 men, 16 women; median age 50; range 18-81) in this series. Initial management was not based on pseudocyst size, duration, location, wall thickness, the patients' symptoms and comorbidity, or the aetiology of pancreatitis. Of the 27 patients who had initial conservative management, 15 pseudocysts (56%) completely resolved. Of the 17 patients who were initially or subsequently treated with percutaneous catheter drainage (PCD), 10 pseudocysts (59%) completely resolved without additional treatment. Of the 13 patients initially or subsequently treated by surgery, all but one completely resolved after the first procedure. Two patients were successfully treated with endoscopic pancreatic stent placement. Complications arose in eight patients treated with PCD (47%) and four patients treated with surgery (31%). There was no mortality. The decision for active treatment was not preceded by delineation of the pancreatic duct by ERCP (endoscopic retrograde cholangiopancreatography) in 60% of patients.

CONCLUSIONS

More than one-third of all patients with symptomatic pancreatic pseudocysts can be managed conservatively. Surgery yields excellent results but PCD has a high failure rate in patients with an underlying pancreatic duct stricture. A rational management algorithm is presented, based on pre-intervention ERCP, which should improve patient selection and outcome.

JNKK1 organizes a MAP kinase module through specific and sequential interactions with upstream and downstream components mediated by its amino-terminal extension

MAP kinase (MAPK) cascades are composed of a MAPK, MAPK kinase (MAPKK), and a MAPKK kinase (MAPKKK). Despite the existence of numerous components and ample opportunities for crosstalk, most MAPKs are specifically and distinctly activated. We investigated the basis for specific activation of the JNK subgroup of MAPKs. The specificity of JNK activation is determined by the MAPKK JNKK1, which interacts with the MAPKKK MEKK1 and JNK through its amino-terminal extension. Inactive JNKK1 mutants can disrupt JNK activation by MEKK1 or tumor necrosis factor (TNF) in intact cells only if they contain an intact amino-terminal extension. Mutations in this region interfere with the ability of JNKK1 to respond to TNF but do not affect its activation by physical stressors. As JNK and MEKK1 compete for binding to JNKK1 and activation of JNKK1 prevents its binding to MEKK1, activation of this module is likely to occur through sequential MEKK1:JNKK1 and JNKK1:JNK interactions. These results underscore a role for the amino-terminal extension of MAPKKs in determination of response specificity.

Inhibition of the p44/42 MAP kinase pathway protects hippocampal neurons in a cell-culture model of seizure activity

Excessive release of glutamate and the subsequent influx of calcium are associated with a number of neurological insults that result in neuronal death. The calcium-activated intracellular signaling pathways responsible for this excitotoxic injury are largely unknown. Here, we report that PD098059, a selective inhibitor of the calcium-activated p44/42 mitogen-activated protein kinase (MAP kinase) pathway, reduces neuronal death in a cell-culture model of seizure activity. Dissociated hippocampal neurons grown chronically in the presence of kynurenate, a broad spectrum glutamate-receptor antagonist, and elevated amounts of magnesium exhibit intense seizure-like activity after the removal of these blockers of excitatory synaptic transmission. A 30-min removal of the blockers produced extensive neuronal death within 24 h as assayed by the uptake of trypan blue and the release of lactate dehydrogenase. Phospho-p44/42 MAP kinase immunoreactivity after 30 min of seizure-like activity was present in many neuronal somata and dendrites as well as some synaptic terminals, consistent with both the presynaptic and postsynaptic effects of this pathway. The addition of PD098059 (40 microM; EC50 = 10 microM) during a 30-min washout of synaptic blockers inhibited the phosphorylation of p44/42 MAP kinase and reduced both the trypan-blue staining (n = 13) and the release of lactate dehydrogenase (n = 16) by 73% +/- 18% and 75% +/- 19% (mean +/- SD), respectively. The observed neuroprotection could be caused by an effect of PD098059 on seizure-like events or on downstream signaling pathways activated by the seizure-like events. Either possibility suggests a heretofore unknown function for the p44/42 MAP kinase pathway in neurons.

Studies of the continuing susceptibility of group A streptococcal strains to penicillin during eight decades

BACKGROUND

In view of the widespread use of penicillin for >50 years for the treatment of group A streptococcal infections, we examined the question of whether there has been a change in susceptibility to penicillin in group A streptococcal strains collected during a span of 80 years (1917 to 1997).

METHODS

One hundred thirty-three group A streptococcal strains collected during 80 years were tested for changes in penicillin susceptibility. Three tests were used: (1) the microtiter broth minimal inhibitory concentration (MIC); (2) the minimal bactericidal concentration (MBC); and (3) the penicillin E strip MIC.

RESULTS

The results indicate there has been no change in the susceptibility to penicillin in these group A streptococci during the past 80 years. The microtiter broth MIC90 for the oldest strains (0.032 microg/ml) was not significantly different from those collected most recently (0.032 microg/ml); there is no statistical difference between the raw MIC data for the four collection periods (P=0.468, analysis of variance on ranks).

CONCLUSIONS

There has been no change in the susceptibility of group A streptococci during this time in spite of well-documented cases of penicillin resistance in other Gram-positive organisms and despite recognized resistance of group A streptococci to other antibiotics.

Establishing a programme for continuous ambulatory infusion chemotherapy

BACKGROUND

The development of venous access devices (VADs) and portable infusion pumps has enabled chemotherapy to be administered continuously within the home environment.

AIM

The objective of this study was to describe the experience of establishing an ambulatory chemotherapy programme for patients receiving protracted infusions (PVIs) of 5-fluorouracil (5-FU).

METHODS

The files of all patients receiving PVI 5-FU as a component of their treatment for gastrointestinal malignancy were reviewed. The types of VADs, infusion pump systems and their management were documented. Information packages and education programmes were developed for patients.

RESULTS

Seventy-four patients with gastrointestinal cancer were studies. At the end of the period the Portacath was the preferred VAD, while both pumps used were found to have advantages and disadvantages. The choice of pump was decided more by patient preference than systematic differences in performance of the pumps.

CONCLUSIONS

The findings in this review confirm that, with close attention to the potential pitfalls of ambulatory chemotherapy, an acceptable service can be provided.

Linear accelerator photon beam quality at off-axis points

Transmitted intensity through water was measured in a narrow-beam geometry for different energy x-ray beams from commercial accelerators. In order to accurately obtain the attenuation coefficient of the incident beam using transmission data, a novel formula was developed based on consideration of beam hardening in phantom. The value of the attenuation coefficient obtained by fitting transmission data to this formula was found to be independent of the absorber thickness used in experiments, whereas the attenuation coefficient obtained from the traditional formula, I(x) = I0 exp(-mux), changed by up to 7% with absorber thickness for a given beam. The beam hardening coefficient obtained from our formula indicates that the attenuation coefficient in water changes by about 0.33% per cm near the surface for the high-energy photon beams studied. Variations in beam quality with off-axis distance were subsequently investigated using the new formula. Results show that the attenuation coefficient at the water surface increased by about 15% for 15 and 18 MV beams, and by 11%-13% for 6 MV beams, when the off-axis distance at 100 cm from the source was changed from 0 to 18 cm. Consideration of the physics of bremsstrahlung production suggests that these variations should be mainly determined by the shape of the flattening filter, i.e., by the path length of rays traversing the filter in different directions. This expectation was confirmed by observing that the attenuation coefficient at the phantom surface can be related to the ray path of the beam in the flattening filter using the new transmission formula.

Muscle patterning, differentiation and vascularisation in the chick wing bud

Adult muscle is highly vascularised, with blood vessels being essential for adequate oxygenation of the tissue and for supporting increased metabolic demands. Whether this is the case during muscle development has not been examined. Resin histology was used to map the muscle splitting process and conventional transmission electron microscopy to examine early muscle differentiation at the midlimb level or later at the mid radius/ulna level in the chick wing bud from stages 24 (4.5 d) to 36 (10 d) (Hamburger & Hamilton, 1951). Microinjection of India Ink into the extra-embryonic vasculature was used to visualise the patent muscle microcirculation. The results showed that the premuscle masses are present at stage 24 and initial splitting of the muscle masses commences at stage 28. The final muscle pattern is not established until stage 36. At stage 26 the cells within the premuscle masses exhibited a mesenchymal morphology, but at stage 28 overt muscle differentiation was evident with myofibrils present within myoblasts. Undifferentiated mononucleated cells were interspersed with the differentiating myoblasts. The ratio of mononucleated cells:myoblasts decreased and the myoblasts became plumper and increasingly packed with myofibrils with age. There was no evidence of secondary myotube formation at any of the stages examined. Vascular invasion of the limb occurred at stage 35 just prior to the establishment of the final muscle pattern. This was surprising as it was assumed that myogenic differentiation would be both oxygen and nutrient dependent. The results of this study provide descriptions of the splitting of the premuscle masses through to the establishment of the final muscle pattern at the midlimb or mid radius/ulna level of the chick wing bud together with the differentiation of the myogenic cells within the developing muscles. However, the relationship between muscle patterning at the tissue level and muscle differentiation at the cellular level with vascularisation remains unclear. It is hoped that the results of the study may provide the basis for future investigations into mechanisms involved in muscle patterning and the signalling mechanisms for vascular invasion.

Activated protein C resistance--low incidence in glaucomatous optic disc haemorrhage and central retinal vein occlusion

PURPOSE

Activated protein C (APC) resistance has recently been reported as conferring a sevenfold increase in the risk of venous thrombosis. It is linked to a genetic mutation in the factor V gene which occurs commonly (about 2% to 4% of the community have the mutation). Glaucoma patients with nerve fibre layer (NFL) haemorrhages on the optic disc and patients with central retinal vein occlusion (CRVO) were tested for APC resistance to determine if there was an association.

METHODS

Twenty-three patients with glaucomatous NFL haemorrhages and 23 patients with CRVO were tested. The CRVO cases included 11 with relatively young age of onset (mean 45.1 +/- 6.9 years) without conventional vascular risk factors. Eighty randomly selected Red Cross blood donor samples and 33 staff members were tested as controls. Clotting times with and without exogenous APC were recorded and an APC ratio determined. Cases with APC resistance were tested to confirm that they had the factor V Leiden gene.

RESULTS

No cases of APC resistance were identified in the glaucoma patients and only one of the younger CRVO patients tested positive, but four of 113 controls tested positive. The difference in prevalence between groups is not significant. The mean APC ratios for the three groups were very similar: NFL haemorrhages 5.46(+/- 1.62), CRVO 5.70(+/- 1.56), controls 5.34 ( +/- 1.19) p > 0.5.

CONCLUSION

There was not clear association detected between glaucomatous NFL haemorrhages or CRVO and APC resistance in this sample of patients. This negative finding is important due its known association with venous thrombosis elsewhere in the body.

Behavioral measures of conduction velocity and refractory period for reward-relevant axons in the anterior LH and VTA

Psychophysical techniques were used to estimate the conduction velocities and refractory periods of reward-relevant fibers in the anterior lateral hypothalamus (ALH) and ventral tegmental area (VTA). Six male rats of the Long-Evans strain served as subjects. Stimulation consisted of trains of pulse pairs delivered to the ALH and VTA; each stimulation site received one pulse from each pair. Collision of antidromic and orthodromic action potentials along the same reward-relevant axons was inferred from a decrease in the effectiveness of the stimulation at short intra-pair intervals. Significant collision-like effects were obtained for 5 of the 6 subjects, supporting the notion that reward-relevant neurons directly link the ALH and VTA. Estimates of the slowest conduction velocities ranged from 0.4 to 5.5 m/s. Refractory period estimates, obtained by delivering the trains of pulse pairs to a single stimulation site, ranged from 0.5 to 5.4 ms. The overlap between these psychophysical estimates and the electrophysiological estimates obtained in the accompanying paper is consistent with the notion that reward-relevant MFB fibers arise in one or several rostral MFB nuclei.

Physiological measures of conduction velocity and refractory period for putative reward-relevant MFB axons arising in the rostral MFB

Extracellular recordings were obtained, in urethane-anesthetized rats, from 44 neurons in the rostral bed nuclei of the medial forebrain bundle (MFB). These cells were antidromically activated by stimulation of MFB sites that typically support self-stimulation. Recording sites included the magnocellular preoptic nucleus, substantia innominata, ventral pallidum, olfactory tubercle, and horizontal limb of the diagonal band. Refractory period estimates ranged from 0.35 to 1.20 ms (mean +/- SD = 0.72 +/- 0.30 ms, n = 15) for stimulation sites in the lateral hypothalamic and ventral tegmental areas when using currents of twice threshold and procedures designed to estimate excitability at or near the site of stimulation. Interelectrode conduction velocity estimates ranged from 1.48 to 20.0 m/s (mean +/- SD = 9.26 +/- 7.22 m/s, n = 11) and were obtained by dividing the interelectrode distance by the difference in the response latency from the two MFB stimulation sites. The refractory period and conduction velocity estimates for these neurons overlap the psychophysically derived estimates for MFB reward neurons. These data are consistent with the hypothesis that neurons arising in the rostral bed nucleus of the MFB compose at least part of the directly activated substrate for MFB self-stimulation.

Attenuation of medical forebrain bundle reward by anterior lateral hypothalamic lesions

Psychophysical data consistent with rostro-caudal conduction along reward-relevant neurons linking the lateral hypothalamus (LH) and ventral tegmental area (VTA) have lead to the hypothesis that some of the directly activated neurons responsible for medial forebrain bundle (MFB) self-stimulation arise anterior to the level of the LH. This hypothesis has been challenged on the grounds that lesions to the anterior LH (ALH) often fail to degrade the rewarding value of stimulating more posterior MFB sites. The present study was aimed at investigating the effect of lesion location and stimulation current on the efficacy of ALH lesions in an effort to account for the inconsistencies in the earlier data. Self-stimulation thresholds were obtained for LH and VTA sites by estimating the number of pulses per stimulation train required for half-maximal responding at each of 3 currents. Electrolytic lesions (anodal, 1.0 mA for 10 s) were then made to the ALH at varying medial-lateral coordinates. In 7 of the 14 rats with MFB stimulation sites, lesions to the ALH produced increases in threshold which often declined over the next several days to weeks; in 5 cases thresholds remained elevated by 0.1 to 0.25 log10 units above baseline up to end of testing. In all but one case, the effective lesions were centered in the lateral ALH. Increases in threshold were more likely to be detected when stimulating at low currents; at low currents fewer neurons are recruited and the lesion can have a greater proportional effect on threshold. These data support the hypothesis that cell bodies, terminals, or fibers of passage in the ALH contribute to the rewarding effect of stimulating more posterior MFB sites.

Safety and efficacy of increasing wintertime vitamin D and calcium intake by milk fortification

We studied the safety and efficacy of milk fortified with vitamin D3 and calcium. Over the winter, we conducted a double-blind, placebo-controlled trial of fortified milk (12 micrograms vitamin D3 and 1525 mg calcium per litre) compared to unfortified milk (0.3 micrograms vitamin D3 and 1270 mg calcium per litre) in 102 adults (aged 17-54 years). Serum 25-hydroxyvitamin D [25(OH)D], ionized calcium, and creatinine were measured at baseline and after intervention. Fortification reduced the seasonal decline in serum 25(OH)D concentrations by > 50%. In the fortified group, serum 25(OH)D decreased by 15 nmol/l from 77 +/- 35 nmol/l to 62 +/- 26 nmol/l (p < 0.001). In the control group, serum 25(OH)D fell by 31 nmol/l from 85 +/- 38 nmol/l to 54 +/- 25 nmol/l (p < 0.001). We suggest that milk enriched with vitamin D be provided in high-latitude European countries to diminish the wintertime fall in serum 25(OH)D.

Parametrization of head-scatter factors for rectangular photon fields using an equivalent square formalism

Head-scatter factors of symmetric square and rectangular fields (field center on the central beam axis) defined by the upper (Y) and lower (X) jaws for 6 and 15 MV photon beams from 2300CD and 600C accelerators (Varian Associates, Inc., Palo Alto, CA) were measured, as well as those for fields shaped by the Y jaws and the multileaf collimator (MLC) of the 2300CD. For rectangular fields, the head-scatter factor for the field (x = a and y = b) was different from that for the field (y = a and x = b). This difference was 2% -3% for fields defined by conventional collimators when [formula, see text] was large, and became 4%-5% when the MLC and YT jaws were used to shape the fields with the X jaws retracted. In order to calculate values for head-scatter factors of rectangular fields accurately using an equivalent square formalism, the side of the equivalent square should be obtained with different weights for lower and upper jaws, as proposed by Vadash and Bjärngard [Med. Phys. 20, 733-734 (1993)]. Our measurements demonstrate that the relative weight (G) of upper and lower jaws is strongly dependent on their distances from the x-ray source, while the beam energy has little effect on the value of G. We further show that G can be calculated simply from these distances. An analytical representation for head-scatter factors of square and rectangular fields is also developed in this paper. The quality of this representation was judged by the root-mean-square (rms) deviation from measured head-scatter factors, which ranged from 0.11%-0.27%.

Variation in N-linked carbohydrate chains in different batches of two chimeric monoclonal IgG1 antibodies produced by different murine SP2/0 transfectoma cell subclones

Two chimeric human/murine monoclonal antibodies were constructed by substitution of the murine constant regions with human gamma 1 and kappa constant regions for heavy and light chains, respectively. The chimeric human/murine molecules are anti-idiotypic antibodies, meaning that they were directed against the antigen binding site in the variable region of another antibody. Antibody batches were produced under identical production conditions, using two selected SP2/0 myeloma cell subclones, which produce chimeric antibodies with different variable regions, but identical constant regions. Several samples were collected during the production of the antibodies in hollow-fibre reactors. The heavy chain, but not the light chain, of the two different chimeric IgG1 antibodies is glycosylated. Structural analysis of the enzymically released N-linked carbohydrate chains by 1H-NMR spectroscopy, as well as by chromatographic profiling, demonstrated that the collection of N-glycans comprises a small amount of monoantennary, and for the greater part diantennary structures. The N-glycans are completely (alpha 1-->6)-fucosylated at the innermost GlcNAc residue. The antennae of the neutral diantennary N-glycans are built up from GlcNAc beta 1-->2, Gal beta 1-->4GlcNAc beta 1-->2 or Gal alpha 1-->3G alpha 1 beta 1-->4GlcNAc beta 1-->2 elements, whereas the antennae of the neutral monoantennary carbohydrate chains have only (beta 1-->2)-linked GlcNAc residues. Galactosylation of the GlcNAc beta 1-->2Man alpha 1-->6 branch occurs four times more frequently than that of the GlcNAc beta 1-->2Man alpha 1-->3 branch, independently of the production batch. A small amount of the diantennary N-glycans are mono- or disialylated, carrying N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid (Neu5Gc), exclusively (alpha 2-->6)-linked to beta Gal. Analysis of the different production batches demonstrates that the structures of the N-linked carbohydrate chains are identical in the two chimeric antibodies, but that the relative amounts of the major oligosaccharide components, the degree of sialylation and the molar ratio of Neu5Ac to Neu5Gc varies with the SP2/0 cell subclone, and only slightly with cell age.

Adaptation to high-fat diets: effects on eating behaviour and plasma cholecystokinin

Twelve male subjects took part in a study to investigate the effects of overfeeding a high-fat diet (19.17 MJ/d; 58% energy from fat) for 2 weeks on plasma cholecystokinin (CCK) levels, food intake, and subjective feelings of hunger and fullness. Before and after the diet, subjects completed a 2-week weighed dietary inventory, formal measurements of food intake from a pre-selected appetizing evening meal were carried out, and blood samples were taken after a standard breakfast for measurement of CCK. Hunger and fullness were rated on visual analogue scales before and after each of these meals and at evening meals during the diet period. Following the high-fat diet there was a small non-significant increase in food intake from the pre-selected meal (6919 (SE 615) kJ v. 6405 (SE 540) kJ; P = 0.1) and a significant increase in the average daily food consumption measured from the diaries (10.25 (SE 0.49) MJ/d v. 9.59 (SE 0.62) MJ/d; P = 0.05). Corresponding trends of increasing feelings of hunger and declining fullness also occurred over the study period. Plasma CCK responses to the standard breakfast were raised following the diet (1285 (SE 153) v. 897 (SE 78) pM min; 3 h integrated CCK production post v. pre diet; P < 0.01) with the major differences observed at 90 and 120 min following the meal. These results suggest that the increase in food intake may be related to a down-regulation in putative CCK receptors responsible for food intake. Elevated CCK levels might suggest a corresponding down-regulation in CCK receptors responsible for feedback inhibition of CCK release.

Evidence implicating both slow- and fast-conducting fibers in the rewarding effect of medial forebrain bundle stimulation

A behavioral version of the collision test was used to determine whether reward-relevant neurons directly link self-stimulation sites in the lateral hypothalamic (LH) and ventral tegmental (VTA) areas. Five male rats served as subjects. Trains of conditioning (C) and test (T) pulses were delivered to the two stimulation sites, each site receiving one of the pulses from each pair. The C-T interval was varied from 0.2-17.3 ms, and the effectiveness of the paired pulse stimulation was estimated by comparing the rate-number curve obtained at each C-T interval to rate-number curves obtained with trains of evenly spaced single pulses delivered via one electrode. For 4 of the subjects, stimulation effectiveness increased with the C-T interval, and the form of this increase was similar regardless of which electrode delivered the C-pulses. These increases in effectiveness are consistent with recovery from collision block in reward-relevant fibers stimulated at both sites. The domain of the rising portion of the effectiveness versus C-T interval curve spanned 2.2-7.7 ms. Such a gradual rise suggests that the directly stimulated substrate is composed of fibers with a wide range of conduction velocities and/or refractory periods. The discrepancy between these gradually rising collision curves and the steeply rising curves obtained in previous collision studies may have been due to inadequate sampling of the rate-number function in the earlier studies.

(-)-Deprenyl alters the survival of adult murine facial motoneurons after axotomy: increases in vulnerable C57BL strain but decreases in motor neuron degeneration mutants

The effect of (-)-deprenyl on the survival of axotomized adult murine facial motoneurons was investigated. Previously, (-)-deprenyl was shown to increase the number of rat facial motoneurons (FMns) surviving after axotomy at postnatal day 14, apparently by compensating for the loss of muscle-derived trophic factor. In the present study, three different strains of adult mice--A/J, C57BL/6J, and a congenic substrain of the C57BL/6J mice, the C57BL/Mnd mutants--underwent unilateral facial nerve transection. FMns were counted from serial sections taken through the entire length of the facial nuclei ipsilateral and contralateral to the facial nerve transections in animals sacrificed 21 days after axotomy. Subgroups of C57BL/6J and Mnd mutants were treated with either saline or 1.0 mg/kg (-)-deprenyl for 21 days. Another subgroup of Mnd mutants were treated with the metabolites of (-)-deprenyl, a mixture of (-)-amphetamine and (-)-methamphetamine, at a dosage equimolar to 1.0 mg/kg (-)-deprenyl. The number of surviving facial motoneurons in the A/J strain was 90% of unlesioned, control values which supports previous findings that adult FMns receive adequate trophic support and thus can survive loss of muscle-derived trophic support. In the C57BL/6J strain, the facial motoneuron survival was 35% and (-)-deprenyl increased the survival to 50.5%. Mnd mutants showed 62.4% survival; however, (-)-deprenyl decreased the number of motoneurons to 54.9% and amphetamine and methamphetamine treatment further decreased the motoneuron survival to 41.1%. These findings show that FMns in the Mnd mutants and their parental strain, C57BL/6J mice, show greater vulnerability to axotomy as compared to other adult strains of mice. The vulnerability is similar to that found in early postnatal life. (-)-Deprenyl increases the survival of the axotomized C57BL/6J FMns but its major metabolites, (-)-methamphetamine and (-)-amphetamine, further decrease FMn survival in the C57BL/Mnd mutants, possibly due to the induction of neurotoxic proteins causing programmed neuronal death. The efficacy of (-)-deprenyl in increasing the survival of damaged neurons would be expected to decrease as dosage increased above the dosage sufficient to induce maximum neuronal rescue (approximately 0.01 mg/kg) but would decrease as the dosage exceeded that necessary to produce toxic concentrations of the metabolites of (-)-deprenyl (1.0 mg/kg in this study).

Plasma P-selectin is increased in thrombotic consumptive platelet disorders

P-selectin is a 140-kD protein found in the alpha-granules of platelets and the Weibel-Palade bodies of endothelial cells that on cell activation is expressed on the cell surface and also secreted into the plasma. The secreted form of P-selectin, like plasma P-selectin, differed from platelet membrane P-selectin in that its molecular mass was approximately 3 kD lower under reducing conditions. Both the secreted and plasma forms of P-selectin contained cytoplasmic sequence as determined by Western blot analysis with an affinity-purified rabbit anti-P-selectin cytoplasmic peptide antibody. We have measured plasma P-selectin and beta-thromboglobulin (beta TG) concurrently in (1) patients with consumptive thrombotic disorders, including disseminated intravascular coagulation (DIC), heparin-induced thrombocytopenia (HIT), and thrombotic thrombocytopenic purpura (TTP)/haemolytic uremic syndrome (HUS); (2) patients with idiopathic thrombocytopenic purpura (ITP); and (3) healthy controls. Patients with DIC, HIT, and TTP/HUS, but not ITP, had significantly elevated plasma P-selectin and beta TG levels when compared with their age-matched healthy controls. The increased plasma P-selectin and beta TG in patients with thrombotic disorders were likely to be the result of in vivo platelet and endothelial cell damage or activation. We also found that avoidance of veno-occlusion and other tedious measures customarily taken during blood collection and sample preparation to prevent in vitro platelet activation did not affect plasma P-selectin assay results. In addition, plasma P-selectin levels were not influenced by the presence of renal failure or heparin administration. These results indicate that plasma P-selectin may be a useful new marker for thrombotic diseases.

Is cholecystokinin a satiety hormone? Correlations of plasma cholecystokinin with hunger, satiety and gastric emptying in normal volunteers

This study was designed to test the putative role of plasma cholecystokinin (CCK) in eating behaviour by examining the relationships between bioassayed plasma CCK concentrations and rated sensations of satiety and hunger following the ingestion of an appetizing nutrient-dense meal and between plasma profiles of CCK and scintigraphically determined gastric emptying in nine healthy male volunteers. Mean plasma CCK levels from the whole group showed a significant negative correlation with mean hunger ratings (r = -0.64) and a positive correlation with fullness (r = +0.68). However, there was considerable interindividual variation and negative correlations with hunger were only seen in three out of nine subjects and positive correlations with fullness in four out of nine subjects. In contrast, there was a strong relationship between the plasma CCK produced over the first 2 h after the meal and the half time for gastric emptying of the meal (r = -0.81). These data do not support a direct role for circulating levels of CCK in the control of hunger and satiety following a meal. Instead, the strong correlation with gastric emptying is compatible with release of CCK in response to nutrient delivery into the small intestine.

New home-delivered training prospects for people with disabilities

The 'Home-Delivered Training Project' set out to test the viability of providing training in Information Technology to people with physical disabilities in their homes, using computers and modem links. The course included core modules on business applications software and optional modules on more specialist applications. The computer-based approach to instruction included computerized monitoring of student progress, the provision of on-line tutorial support as well as computerized test administration and marking. The 20 course participants, who lived in locations throughout Ireland, were unable to attend conventional training centres because of their limited mobility or other restrictions arising from their disabilities. They differed considerably in terms of disability type, educational qualifications and experience with computers. All but one of them completed the course successfully and were awarded certificates which are recognized in Ireland and the United Kingdom. Overall, they were very positive about the course, mainly because they could undertake it in their homes at a flexible pace to suit their learning patterns and the requirements of their disabilities. They recognized, however, that studying at home required a self-disciplined study routine which was not always easy to maintain. The fact that they were awarded an internationally recognized qualification on completion of the course was an important motivating factor, as it made the course relevant in terms of their employment aspirations.

The prevalence of microalbuminuria and associated risk factors in a population with insulin-dependent diabetes mellitus

The prevalence of microalbuminuria was studied in a clinic population of patients with insulin-dependent diabetes mellitus [IDDM] with disease duration longer than 5 years. 75 patients were included in the study, 23 patients (30.7%) had microalbuminuria and 2 patients (2.7%) had macroalbuminuria. Comparison of the clinical and laboratory characteristics of patients with microalbuminuria (n = 23) to patients with normoalbuminuria (n = 50) showed no differences with respect to age, duration of diabetes, blood pressure, presence of retinopathy and glycosylated haemoglobin. The mean glomerular filtration rate (GFR) was higher in the microalbuminuric group than in the normoalbuminuric group (125 +/- 45 ml/min compared to 99 +/- 32 ml/min; P < 0.05). In a multiple regression model excluding patients with macroalbuminuria the following predictors of albumin excretion rate (AER) were identified: systolic blood pressure, glycosylated haemoglobin and GFR. Since microalbuminuria is common in Irish patients with IDDM, we suggest that AER should be determined as part of the annual routine screen. Stricter control of blood pressure and glycaemia should be considered.