bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of early postoperative 5-fluorouracil and ageing on the healing capacity of experimental intestinal anastomoses
Authors: Stoop M J , Dirksen R , Wobbes T , Hendriks T
Published: July 2002

Background

Results from a previous study suggested that advanced age does not affect early repair of experimental intestinal anastomoses. The present study aimed to establish whether anastomotic healing is impaired more easily in old animals by immediate postoperative chemotherapy.

Methods

Young adult (2–3 months) and old (27–30 months) rats underwent resection and anastomosis of both ileum and colon. Within each age group, subgroups received intraperitoneal saline or 5-fluorouracil in a dose of 15 or 20 mg per kg per day from the day of operation onwards. After 7 days, anastomotic healing was assessed by wound strength and collagen deposition in the wound area.

Results

No differences were found between young and old control groups. The higher dose of fluorouracil induced severe loss of strength with concomitant reduction of wound collagen, which was similar in both age groups (ileum: from 52(13) to 24(8) volume per cent in young animals and from 56(10) to 20(9) volume per cent in old animals; colon: from 58(10) to 37(18) volume per cent in young animals and from 65(5) to 30(17) volume per cent in old animals). The lower dose of fluorouracil induced a significantly greater loss of strength, measured as the bursting pressure, in the old animals (150(49) versus201(59) mmHg in colon of young rats).

Conclusion

In this model early anastomotic repair in older animals proceeds normally under optimal conditions, but it is more easily disturbed in the presence of fluorouracil.
Warfarin induced skin necrosis
Authors: Chan Y C , Valenti D , Mansfield A O , Stansby G
Published: July 2002

Background

Warfarin induced skin necrosis is a rare complication with a prevalence of 0·01–0·1 per cent. It was first described in 1943.

Methods

A literature review was undertaken using Medline; all relevant papers on this rare compli-cation of warfarin therapy were used.

Results

There are several adverse skin manifestations associated with the use of oral anticoagulants, ranging from ecchymoses and purpura, haemorrhagic necrosis, maculopapular vesicular urticarial eruptions to purple toes. This article concentrates mainly on warfarin induced skin necrosis. The syndrome typically occurs during the first few days of warfarin therapy, often in association with the administration of a large initial loading dose of the drug. Although the precise nature of the disease is still unknown, advances in knowledge about protein C, protein S and antithrombin III anticoagulant pathways have led to a better understanding of the mechanisms involved in pathogenesis. Differential diagnosis between warfarin induced skin necrosis and necrotizing fasciitis, venous gangrene and other causes of skin necrosis may be difficult; the disease may also be confused with other dermatological entities.

Conclusion

Warfarin induced skin necrosis, while rare, is an important complication. All surgeons should be aware of its existence.
Prospective study of the effect of laparoscopic hemifundoplication on motor and sensory function of the proximal stomach
Authors: Vu M K , Ringers J , Arndt J W , Lamers C B H W , Masclee A A M
Published: July 2002

Background

Some 30 per cent of patients develop dyspeptic symptoms following antireflux surgery. These symptoms may result from alterations in the motor and sensory function of the proximal stomach.

Methods

Proximal gastric motor and sensory function was studied with an electronic barostat in 12 patients with reflux who underwent laparoscopic hemifundoplication. In addition, 24-h pHmetry, gastric emptying (scintigraphy) and vagus nerve integrity (pancreatic polypeptide response to hypo-glycaemia) were assessed. Fifteen healthy volunteers served as controls.

Results

Laparoscopic hemifundoplication significantly decreased total acid exposure time (P < 0·05). Vagus nerve function remained intact in all but one patient. The mean(s.e.m.) lag phase for emptying of solids was significantly shorter after operation than before (15(3) versus 21(3) min; P < 0·05). Proximal gastric compliance was not significantly different before and after fundoplication. However, mean(s.e.m.) postprandial relaxation was significantly reduced (P < 0·05) after hemifundoplication compared with the value before operation (3341(1105) versus 12 763(3616) ml over 90 min) and in controls (14 567(2358) ml over 90 min). Postprandial fullness was significantly increased after hemi-fundoplication (P < 0·05). Postprandial gastric relaxation correlated with the lag phase for emptying of solids (r = 0·55, P < 0·02).

Conclusion

After hemifundoplication, proximal gastric compliance is not altered but postprandial relaxation is impaired and associated with sensations of fullness and shorter duration of the lag phase for emptying of solids.
Cost-effective carotid endarterectomy
Authors: Sandison A J P , Wood C H , Padayachee T S , Colchester A C F , Taylor P R
Published: July 2002

Background

Although carotid endarterectomy is increasing in the UK, there is evidence that the procedure is still underused. Methods of reducing cost in a single vascular unit have been assessed using a continuous audit including outcome measures.

Methods

A consecutive series of 333 patients admitted over 7 years under a single consultant surgeon were studied. Outcome measures included the rate of perioperative neurological complication of any kind, and death. The length of hospital stay and the number of readmissions within 30 days were recorded prospectively by computerized audit.

Results

Over the interval of the study, the number of preoperative investigations was reduced; angiography and cerebral computed tomography were reserved for specific indications. The median duration of hospital stay decreased from 7 to 2 days. There was no change in the stroke and death rate (3 per cent) during the study and only two patients required readmission within 30 days.

Conclusion

Carotid endarterectomy can be performed cost-effectively using non-invasive preoperative investigations for the majority of patients. In-hospital stay has been reduced and the routine use of intensive care replaced by a 2-h stay in theatre recovery. These changes have been achieved without compromising patient safety.
Near-infrared spectroscopy grades the severity of intermittent claudication in diabetics more accurately than ankle pressure measurement
Authors: Komiyama T , Shigematsu H , Yasuhara H , Muto T
Published: July 2002

Background

The aim of this study was to evaluate near-infrared spectroscopy (NIRS), combined with a treadmill-walking test, as a method of assessment of intermittent claudication (IC) in diabetic patients.

Methods

Some 208 symptomatic legs in 153 consecutive patients who complained of calf IC due to atherosclerotic disease were studied with NIRS and resting ankle: brachial pressure index (ABPI).

Results

There was good reproducibility of NIRS measurements. Three distinct types of IC were detected by NIRS. ABPI was significantly different between these three types in non-diabetic patients, but could not grade the severity of IC in diabetic patients. Recovery time (RT) of muscle oxygenation differentiated more accurately between severe and moderate claudication than ABPI in diabetics, although RT and ABPI had similar accuracy in non-diabetics. There was a significant correlation between RT and ABPI in non-diabetic patients and patients who had been diabetic for less than 10 years, while there was no correlation in patients who had had diabetes for over 10 years.

Conclusion

Measurement of muscle oxygenation during exercise by NIRS graded the severity of IC in diabetic patients more accurately than resting ABPI.
Portal vein thrombosis following splenectomy
Authors: Hassn A M F , Al-Fallouji M A , Ouf T I , Saad R
Published: July 2002

Aims

The aim of this study was to assess the risk and progress of portal vein thrombosis (PVT) after splenectomy.

Methods

A prospective study was conducted in which two groups of patients were compared; each group comprised 50 patients (27 men, 23 women). Patients in the splenectomy group were of mean age 46·3 years. A second group of patients (mean age 48·5 years) had upper abdominal surgery other than splenectomy. All patients were examined before and 2 weeks after operation by duplex Doppler ultrasonography (DDUS) of the portal system. Those who developed PVT were followed up by DDUS at 6 and 12 months.

Results

PVT developed in 10 per cent of patients who underwent splenectomy. The portal vein was completely occluded by thrombus in 4 per cent and partially occluded in 6 per cent of patients. Symptoms and signs attributable to PVT (abdominal pain, diarrhoea, nausea, vomiting and mild fever) were found in 80 per cent of those who developed this complication. Follow-up of such patients revealed complete recanalization of portal vein in 40 per cent and partial recanalization in 60 per cent after treatment with antibiotics and long-term anticoagulation therapy. No patient who underwent upper abdominal surgery (other than splenectomy) developed PVT afterwards.

Conclusions

Splenectomy (compared with other upper abdominal surgery) is followed by PVT in 10 per cent of patients but can be treated successfully.
Early results of laparoscopic Swedish adjustable gastric banding for morbid obesity
Authors: Wright T A , Kow L , Wilson T , Toouli J
Published: July 2002

Aims

Gastric bypass and vertical banded gastroplasty (VBG) are currently the most commonly performed bariatric procedures but neither are ideal. The results of the first 56 patients who had laparoscopic Swedish adjustable gastric banding (SAGB) are presented.

Methods

All patients referred for bariatric surgery were considered for SAGB. Each was given the alternative of gastric bypass. Patients with a body mass index of less than 35, large hiatus hernia, under 18 years of age, gastric pathology and significant psychiatric illness were excluded. Preoperative gastroscopy, ultrasonographic examination of the gallbladder and specialist anaesthetic assessment were arranged. All but five patients had attempted laparoscopic procedures. Patients were discharged when they were mobile and could tolerate 1500 ml fluid per day. Patients were given a liquidized diet for 6 weeks. Assessments were made at 6 weeks and 3, 6, 9 and 12 months.

Results

Some 56 consecutive patients were followed for up to 12 months. The conversion rate fell from 52 per cent for the first 25 patients to 20 per cent for the last 20. Conversion rates were higher in men and in superobese patients. The duration of a laparoscopic operation fell significantly with experience but was still significantly longer than that of an open procedure (P < 0·004). The length of hospital stay was significantly shorter for laparoscopic procedures (P < 0·001). There was no death and little morbidity. Two bands had to be removed (easily) by open surgery, one for infection and one for a recurrence of gastric herniation. The mean excess weight loss was 60 per cent at 12 months. Greater than 50 per cent of excess body-weight was lost by 48 per cent of patients at 6 months and 69 per cent at 12 months. Band adjustments in most patients achieved further weight loss to compensate for late pouch dilatation. Most failures were in patients who failed to attend.

Conclusions

SAGB appears to have many advantages over gastric bypass and VBG; it avoids stapling the stomach, should not cause any malabsorption, can be performed laparoscopically, is adjustable, is more readily reversed (if necessary) and, therefore, has the potential for lower associated morbidity and mortality rates. In terms of excess weight loss, the early results are certainly as good, if not better, than those of gastric bypass and VBG.
Management of spontaneous rupture of the oesophagus
Authors: Shenfine J , Dresner S M , Vishwanath Y , Hayes N , Griffin S M
Published: July 2002

Aims

Spontaneous rupture of the oesophagus (SRO) is a rare and often fatal event. The aim of this study was to evaluate the presentation, management and outcome of SRO in a single unit.

Methods

Data were collected on all patients presenting with SRO over a 5-year period with respect to presenting features, diagnostic investigations and subsequent management. Statistical analysis was by Student's t test, χ2 and Fisher's exact tests.

Results

Fourteen patients were identified, 12 men and two women with a median age of 64 (range 18–78) years; eight were tertiary referrals. Thirteen of 14 patients presented with chest or upper abdominal pain following vomiting or retching and 13 had an abnormal initial chest radiograph; only one presented with Mackler's triad of pain, vomiting and surgical emphysema. The median delay to diagnosis was 21 (range 1–84) h; this delay did not significantly affect outcome (P = 0·16). An endoscopic assessment and contrast swallow were performed in all patients. Nine of ten patients with a demonstrable leak and full-thickness tear were managed surgically and the four patients with no leak were managed conservatively (P = 0·005); surgical management consisted of thoracotomy, lavage, repair of the perforation and a feeding jejunostomy. Seven patients had a repair over a T tube and two had a primary repair. All conservatively managed patients had contained, controlled or intramural perforations and two also required a feeding jejunostomy. Patients requiring surgery had a longer hospital stay (mean(s.d.) 57·9(34·8) versus 22·2(30·7) days; P = 0·081) and a significantly longer intensive care unit stay (P = 0·044). The overall mortality rate from SRO was 14 per cent (two patients); no deaths occurred in the conservatively managed group.

Conclusions

SRO continues to be diagnosed late despite a classical history and/or abnormal chest radiograph. Endoscopic assessment of perforations is safe and in combination with a contrast swallow can confidently predict patients with contained or controlled rupture in whom non-operative management is successful.
Comparison of the effect of primary and recurrent varicose vein surgery on symptoms and quality of life
Authors: Paisley A M , Bradbury A W
Published: July 2002

Background

Surgeons are being increasingly asked to justify interventions for primary and particularly recurrent varicose veins (VVs). The effect of primary and recurrent VV surgery on disease-specific and generic quality of life (QoL) was compared.

Methods

This was a prospective study of 251 consecutive patients. Aberdeen VV symptom severity score (AVSS) (disease-specific) and Short Form 36 (SF-36) (generic) QoL questionnaires were completed before, and 4 weeks and 6 months after operation. Statistical analysis was by non-parametric methods.

Results

Some 77 per cent of patients with primary VVs (n = 130) and 74 per cent with recurrent VVs (n = 67) completed three questionnaires. Before operation, patients with recurrent VVs had significantly worse (higher) disease-specific QoL (median (interquartile range (i.q.r.)) AVSS 22·1 (14·6–29·7) versus 17·0 (11·3–24·5); P = 0·004) than those with primary VVs. At 4 weeks, the AVSS had only improved significantly in the primary group, but at 6 months was significantly improved in both primary (7·6 (3·1–14·7); P = 0·001) and recurrent (13·1 (7·8–19·5); P = 0·001) groups. Before operation, SF-36 emotional role (median (i.q.r.) 100 (33–100) versus 100 (100–100); P = 0·016) and vitality (58 (40–75) versus 65 (50–80); P = 0·026) were also significantly worse (lower) in the recurrent group. At 6 months, there was a significant improvement in bodily pain in both groups (primary 74 (51–100) versus 84 (62–100), P = 0·001; recurrent 62 (41–100) versus 74 (51–100), P = 0·007); and in physical functioning (85 (64–95) versus 93 (70–100); P = 0·001) and physical role (100 (50–100) versus 100 (94–100); P = 0·003) in patients with primary VVs.

Conclusion

Surgery for primary and recurrent VVs confers a highly significant improvement in disease-specific and, to a lesser extent, generic QoL.
Effect of occlusal trauma on healing of periapical pathoses: report of two cases
Authors: Harn W‐M. , Chen M‐C. , Chen Y‐H. M. , Liu J‐W. , Chung C‐H.
Published: July 2002

Aim

To present two clinical cases and demonstrate that occlusal trauma may affect healing of periapical pathoses.

Two teeth with periradicular disease did not respond successfully to conventional root canal treatment or endodontic surgery. Occlusal adjustment was finally performed on both cases. After occlusal adjustment, uncomplicated healing and periapical repair occurred in both cases. The findings in these two cases suggest that occlusal trauma may play a role in the healing of periapical pathoses.

Key learning points

Occlusal trauma is positively correlated with changes in periodontal tissues.

Although experiments in animals have shown that application of forces to teeth will not induce further periodontal destruction, we believe that some failures of root canal treatment may be due to the presence of occlusal trauma modulating the responses of inflamed periapical tissues or apical pathoses with persistent infection.
New approximations for the variance in Cavalieri sampling
Authors: García‐Fiñana M. , Cruz‐Orive L. M.
Published: July 2002

The theory of Cavalieri sampling − or systematic sampling along an axis − has received a recent impetus. The error variance may be represented by the sum of three components, namely the extension term, the ‘Zitterbewegung’, and higher order terms. The extension term can be estimated from the data, and it constitutes the standard variance approximation used so far. The Zitterbewegung oscillates about zero, and neither this nor higher order terms have hitherto been considered to predict the variance. The extension term is always a good approximation of the variance when the number of observations is very large, but not necessarily when this number is small. In this paper we propose a more general representation of the variance, and from it we construct a flexible extension term which approximates the variance satisfactorily for an arbitrary number of observations. Furthermore, we generalize the current connection between the smoothness properties of the measurement function (e.g. the section area function of an object when the target is the volume) and the corresponding properties of its covariogram to facilitate the computation of the new variance approximations; this enables us to interpret the behaviour of the variance from the ‘overall shape’ of the measurement function. Our approach applies mainly to measurement functions whose form is known analytically, but it helps also to understand the behaviour of the variance when the measurement function is known at sufficiently many points; in fact, we illustrate the concepts with both synthetic and real data.
Mental Health Triage in Emergency Medicine
Authors: Smart David , Pollard Cecily , Walpole Bryan
Published: July 2002

Objective: The aim of this study was to: (i) develop a triage scale consistent with the National Triage Scale (NTS) for patients with mental health problems attending emergency departments; and (ii) to reduce emergency waiting times, transit times and improve skills assessing mental health problems.

Method: We developed a Mental Health Triage Scale (MHTS) consistent with the NTS. The MHTS was then implemented using a structured education package, and evaluated from March to August 1994. Further evaluation occurred after 2 years.

Results: Afour-tiered MHTS was produced: category 2, violent, aggressive or suicidal, danger to self or others or with police escort; category 3, very distressed or psychotic, likely to deteriorate, situational crisis, danger to self or others; category 4, long-standing semi-urgent mental health disorder, supporting agency present; and category 5, long-standing non-acute mental health disorder, no support agency present. Patients with illness, injury or self-harm were triaged using combined mental health and medical information. Mean emergency waiting times and transit times were reduced. More consistent triaging for mental health patients occurred, and more consistent admission rates by urgency. Reduced mental health ‘did not waits’ showed improved customer satisfaction. Mental Health Triage Scale was considered appropriate by liaison psychiatry and its use has continued at 2 years follow-up.

Conclusions: Asystematic approach to mental health triaging produced a workable scale, reduced waiting times, transit times, and provided effective and consistent integration of mental health patients into a general emergency department.
Nefazodone for Patients with Chronic Fatigue Syndrome
Authors: Hickie Ian
Published: July 2002

Objective: Patients with chronic fatigue syndrome (CFS) present with a variety of musculoskeletal, neurocognitive, sleep disturbance and mood symptoms. An open evaluation of the clinical utility of the novel antidepressant compound, nefazodone, was completed.

Method: Ten patients with CFS presenting for assessment by a specialist psychiatrist were treated with nefazodone. Patients treated within this specialist service are also advised to engage in appropriate behavioural and sleep-wake cycle strategies to improve their level of functioning.

Results: Of the 10 patients, eight (80%) reported at least some improvement in the key symptom of fatigue, with four (40%) reporting moderate or marked symptom relief. Additionally, sleep disturbance and mood were both moderately or markedly improved in seven (70%) and eight (80%) of the patients, respectively. Five of the patients (50%) achieved at least a moderate improvement in overall functional outcome and were able to return to work or their previous level of role function. The mean dose of nefazodone was 370 mg/day (range == 200–800 mg), with a strong preference for nocturnal dosing. Seven of the patients had previously failed to respond to moclobemide, while seven had previously failed to respond to conventional antidepressant therapy.

Conclusion: Nefazodone appears to be worthy of further systematic investigation in patients with CFS. Given its effects on sleep, mood and anxiety symptoms, it may have particular advantages in patients with this disorder.
Qigong-Induced Mental Disorders: A Review
Authors: Ng Beng-Yeong
Published: July 2002

Objective: This review article aims to explore current opinions on Qigong-induced mental disorders, an entity which is unfamiliar to Western psychiatrists.

Method: Relevant literature published in Chinese and English is reviewed. Results: The review is divided into three sections: first, there is brief consideration of the historical development of Qigong in traditional Chinese medicine and its role in psychiatry; second, there is a review of the literature published on Qigong deviations and Qigong-induced mental disorders; and third, there is a discussion on the aetiological role of Qigong in these conditions.

Conclusions: Qigong remained veiled in secrecy and available only to the elite until the early 1980s. Despite the widespread use of Qigong, there is a conspicuous lack of controlled data regarding its effects on mental health. Qigong, when practised inappropriately, may induce abnormal psychosomatic responses and even mental disorders. However, the ties between Qigong and mental disorders are manifold, and a causal relationship is difficult to establish. Many so-called ‘Qigong-induced psychoses’ may be more appropriately labelled ‘Qigong-precipitated psychoses’, where the practice of Qigong acts as a stressor in vulnerable individuals.
Sex, Honesty and the Supervisory Relationship: a Response to Ryan
Authors: Clarke David M.
Published: July 2002

Objective: An argument has been presented in this journal for a generally permissive attitude to consensual sexual relations between psychiatrists and trainee psychiatrists except in circumstances where there is a direct supervisory relationship. This paper challenges that view.

Method: The arguments are reviewed. A developmental perspective of training is used to show that the autonomy of trainees is restricted in a manner similar to a student in relation to a teacher. This confers on psychiatrists a duty of care.

Results: On the basis of respect for autonomy, the strength of argument for a prohibition on consensual sexual relationships is strong for a young trainee, and weakens as a person proceeds through training and approaches the status of a colleague. Apolicy of restraint would facilitate the development of a general atmosphere of trust, which is an important requirement for good supervision and the basis of professional relationships. An ethical judgement cannot be made, however, without the consideration of other relationships and commitments existing outside the supervisory relationship for each person involved.

Conclusions: In order to create a secure and unambiguous training environment that maximises trust, a general principle of prohibition on sexual relationships between psychiatrists and trainees is preferred, although circumstances exist where such relationships are not unethical.
Efficacy, Effectiveness and Efficiency in Mental Health Service Delivery
Authors: Andrews Gavin
Published: July 2002

Objective: The aim of this paper is to review the status of treatments in psychiatry.

Method: The criteria for good treatment are defined and then treatments in psychiatry are examined for efficacy, effectiveness and efficiency.

Results: Alarge number of treatments were listed by Nathan and Gorman as having satisfied the criteria for efficacy: that is, they had been shown to be superior to placebo in randomised controlled trials. The problem of effectiveness (does the treatment still work when used by the average clinician with the average patient?) is a general one in medicine, but the evidence in psychiatry is not outstanding. The problem of efficiency (what level of resources are required to produce benefit?) is being addressed in a piecemeal fashion, and again this is no different to the situation in general medicine.

Conclusions: Aconsiderable number of treatments have been shown to satisfy the criteria for efficacy. Effectiveness requires that psychiatrists apply such proven treatments and demonstrate benefit through the use of outcome measurement. A system that separated the health budget into segments for prevention, cure and care might ensure that these three goals were pursued equitably and efficiently.
Summary of Changes to the RANZCP Code of Ethics
Authors: Steinberg Ben
Published: July 2002

The first revision of the 1992 Code of Ethics of the RANZCP was endorsed by the General Council of the College at its meeting in October 1998.
Cavernous haemangiomas (angiomas) of the brain
Authors: Sage Michael R , Blumbergs Peter C
Published: July 2002

This paper highlights the importance of cavernous haemangiomas as clinically significant lesions and the role of imaging, particularly MRI, in suggesting the diagnosis. An understanding of the pathology of these lesions helps to explain the features demonstrated by imaging techniques.
Physiological effects and adjuvanticity of recombinant brushtail possum TNF‐α
Authors: Wedlock DN , Goh LP , McCarthy AR , Midwinter RG , Parlane NA , Buddle BM
Published: July 2002

The present paper describes the physiological properties of recombinant possum TNF‐α and an adjuvant effect on antibody responses to the model protein antigen, keyhole limpet haemocyanin (KLH). For these studies recombinant possum TNF‐α was produced in the yeast Pichia pastoris. The recombinant cytokine was secreted into the culture medium and purified by gel filtration. Possum TNF‐α produced in this expression system was N‐glycosylated and bioactive in two different assays. In a murine fibroblast L929 cytotoxicity assay, the possum TNF‐α had lower specific activity compared to human TNF‐α, while in a possum‐specific assay, possum TNF‐α enhanced the proliferation of PHA‐stimulated possum thymocytes and was more active than human TNF‐α. The physiological effect of the recombinant possum TNF‐α was investigated in groups of possums administered doses of 6, 30 or 150 μg of cytokine. For each dose, TNF‐α caused profound effects on the numbers of circulating leucocytes characterized by a three‐to‐four‐fold increase in neutrophil numbers at 6–24 h after injection and an initial sharp decrease in lymphocyte numbers. The efficacy of TNF‐α as an immunological adjuvant was determined in possums administered KLH (125 μg) in an aqueous or Al(OH)3‐based formulation with or without added recombinant TNF‐α (150 μg). Serum antibody responses to KLH were monitored by ELISA. The TNF‐α stimulated two‐fold and four‐fold increases in antibody levels in aqueous and Al(OH)3‐based vaccine formulations, respectively. The strongest antibody responses were observed in the group of possums that received KLH formulated in Al(OH)3 with addition of TNF‐α.
Overactivation of α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate and N‐methyl‐d‐aspartate but not kainate receptors inhibits phosphatidylcholine synthesis before excitotoxic neuronal death
Authors: Gasull Teresa , DeGregorio‐Rocasolano Nuria , Trullas Ramon
Published: July 2002

Glutamate receptor overactivation induces excitotoxic neuronal death, but the contribution of glutamate receptor subtypes to this excitotoxicity is unclear. We have previously shown that excitotoxicity by NMDA receptor overactivation is associated with choline release and inhibition of phosphatidylcholine synthesis. We have now investigated whether the ability of non‐NMDA ionotropic glutamate receptor subtypes to induce excitotoxicity is related to the ability to inhibit phosphatidylcholine synthesis. α‐Amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA)‐induced a concentration‐dependent increase in extracellular choline and inhibited phosphatidylcholine synthesis when receptor desensitization was prevented. Kainate released choline and inhibited phosphatidylcholine synthesis by an action at AMPA receptors, because these effects of kainate were blocked by the AMPA receptor antagonist LY300164. Selective activation of kainate receptors failed to release choline, even when kainate receptor desensitization was prevented. The inhibition of phosphatidylcholine synthesis evoked by activation of non‐desensitizing AMPA receptors was followed by neuronal death. In contrast, specific kainate receptor activation, which did not inhibit phosphatidylcholine synthesis, did not produce neuronal death. Choline release and inhibition of phosphatidylcholine synthesis were induced by AMPA at non‐desensitizing AMPA receptors well before excitotoxicity. Furthermore, choline release by AMPA required the entry of Ca2+ through the receptor channel. Our results show that AMPA, but not kainate, receptor overactivation induces excitotoxic cell death, and that this effect is directly related to the ability to inhibit phosphatidylcholine synthesis. Moreover, these results indicate that inhibition of phosphatidylcholine synthesis is an early event of the excitotoxic process, downstream of glutamate receptor‐mediated Ca2+ overload.
Development of pupillary responses to grating stimuli*
Authors: Cocker Kenneth D. , Moseley Merrick J.
Published: July 2002

Pupillary responses to stationary, achromatic sine wave gratings were measured in adults and in 1‐ and 3‐month‐old infants. Measurements of behaviourally determined contrast sensitivity were also obtained from the infant subjects. Contrast sensitivity functions were typical of those previously described: band‐pass in nature with sensitivity increasing markedly with age. The pupil grating response amplitudes also exhibited a spatial frequency and age dependence similar to that observed for contrast sensitivity. These findings provide further evidence that the neural mechanisms which underlie visual sensitivity to contrast also mediate pupillary responses to spatial structure.
A longitudinal study of cycloplegic refraction in a cohort of 350 Japanese schoolchildren. Cycloplegic refraction
Authors: Watanabe S. , Yamashita T. , Ohba N.
Published: July 2002

We performed a 5 year longitudinal study of cycloplegic refraction in a cohort of 350 Japanese schoolchildren from 6 to 11 years of age in a rural area of southwestern Japan. The spherical refraction was measured under cycloplegia with an infrared autorefractometer. The grouped data from 350 right eyes showed leptokurtic frequency distributions, and the median was +0.91 D at age 6 yrs, shifted towards emmetropia with increasing age and reached +0.34 D at age 11 years. The prevalence of myopia of −1.0 D or more was 0.3%, 0.6%, 2.0%, 2.6%, 2.9%, and 4.9% from age 6 to 11 years, and the prevalence of myopia of more than −2.0 D was less than 1% at age 6–9 years and thereafter increased up to 6.0% at age 11 years. Linear regression analysis for the longitudinal refractive data revealed that 247 (70.6%) of the 350 eyes exhibited first‐order linear decrease in hyperopia or increase in myopia with an average annual change of −0.15 D/year, 14 (4%) showed second‐order curvilinear change, and 89 (25.4%) remained unchanged. In the eyes with linear change, there was a significant relationship between the refraction at age 6 years and the rate of subsequent change such that the less hyperopic or emmetropic at age 6 years, the larger the change. The refraction at birth was estimated by extrapolation of the linear regression analysis results, implying that 88% of newborns have hyperopia of +1.0 D or greater and myopia is rare. These results indicate the current state of refraction in Japanese schoolchildren of a rural area.
Vaquita Bycatch in Mexico's Artisanal Gillnet Fisheries: Driving a Small Population to Extinction
Authors: D'agrosa Caterina , Lennert‐Cody Cleridy E. , Vidal Omar
Published: July 2002

Abstract: The world's most endangered marine cetacean, the vaquita (  Phocoena sinus), continues to be caught in small‐mesh gillnet fisheries throughout much of its range. We monitored fishing effort and incidental vaquita mortality in the upper Gulf of California, Mexico, from January 1993 to January 1995 to study the magnitude and causes of the incidental take. Of those factors studied, including net mesh size, soaktime, and geographic area, none contributed significantly to the incidental mortality rate of the vaquita, implying that the principal cause of mortality is fishing with gillnets per se. The total estimated incidental mortality caused by the fleet of El Golfo de Santa Clara was 39 vaquitas per year (95% CI = 14, 93), over 17% of the most recent estimate of population size. El Golfo de Santa Clara is one of three main ports that support gillnet fisheries throughout the range of the vaquita. Preliminary results indicate that fishing effort for San Felipe, Baja California, is comparable to that of El Golfo de Santa Clara, suggesting that this estimate of incidental mortality of vaquitas represents a minimum. We strongly recommend a complete and permanent ban on gillnets in the area. Alternative or supplemental mitigation strategies include (1) a maximum annual allowable mortality limit of vaquitas; (2) mandatory observer coverage of all boats fishing within the Upper Gulf of California and Colorado River Delta Biosphere Reserve; (3) extension of the Upper Gulf of California and Colorado River Delta Biosphere Reserve to encompass all known vaquita habitat; (4) rigorous enforcement of new and existing regulations; and (5) development of alternative sources of income for gillnet fishers.
Cognitive Impairment after Stroke: Clinical Determinants and Its Associations with Long‐Term Stroke Outcomes
Authors: Patel Mehool D. , Coshall Catherine , Rudd Anthony G. , Wolfe Charles D. A.
Published: July 2002

OBJECTIVES: To identify factors that were associated with cognitive impairment 3 months after stroke, and to examine the associations of cognitive impairment with stroke outcomes up to 4 years after stroke.

DESIGN: Observational study.

SETTING: Population‐based stroke register.

PARTICIPANTS: Six hundred forty‐five subjects with first‐ever stroke, identified from the register.

MEASUREMENTS: Subjects were assessed for cognition using the Mini‐Mental State Examination (MMSE) 3 months after stroke. Cognitively impaired subjects (MMSE <24, n = 248 (38%)) were compared with cognitively intact subjects (MMSE 24–30, n = 397) in terms of demographic details, stroke risk factors, laterality of stroke, and initial poststroke impairments. Outcome data collected at 1, 3, and 4 years poststroke included disability assessed by the Barthel Index (BI) and the Frenchay Activity Index, case fatality, and institutionalization.

RESULTS: Two hundred forty‐eight (38%) of 645 subjects were cognitively impaired 3 months after stroke. Using multivariate analyses, cognitive impairment was associated with age of 75 and older (odds ratio (OR) = 2.5, 95% confidence interval (CI) = 1.5–4.2), ethnicity (Caribbean/African (OR = 1.9, 95% CI = 1.2–3.2) and Asian (OR = 3.4, 95% CI = 1.1–10.2), lower socioeconomic class (OR = 2.1, 95% CI = 1.3–3.3), left hemispheric lesion (OR = 1.6, 95% CI = 1.01–2.4), visual field defect (OR = 2.0, 95% CI = 1.2–3.2), and urinary incontinence (OR = 4.8, 95% CI = 3.1–7.3). Using multivariate analyses, cognitive impairment was associated with death or disability (BI <15) at 4 years after stroke (OR = 2.2, 95% CI = 1.1–4.5). In univariate analyses, it was also associated with higher institutionalization 4 years after stroke (P = .001).

CONCLUSIONS: Cognitive impairment is common 3 months after stroke and is independently associated with older age, ethnicity, lower social class, left hemispheric stroke, visual field defect, and urinary incontinence. It is associated with poor long‐term outcomes, including survival and disability, up to 4 years after stroke. Because physical and cognitive impairments after stroke have independent prognostic implications, measures that evaluate both functions should be used in future studies of stroke outcome and in care of stroke patients.
Both Intact Microfilaments and Cortical Microtubules are Involved in the Maintenance of the Growth Rate of Internodal Cells of Nitellopsis
Authors: Zhu G. L. , Zhu R. , Zhou W. , Ye Q. , Chen Z. L. , Yuan M.
Published: July 2002

Abstract: Automatic monitoring, with an eddy‐current displacement transducer, treatments with CD and oryzalin separately, and with CD plus oryzalin in combination (CD = 10 mg/l, and oryzalin = 10 ìmol/l) were used to follow the elongation growth of internodal cells of Nitellopsis. These showed similar kinetics in inhibition and recovery tests. Inhibition to growth started about 10 to 15 min after treatment. However, complete inhibition to growth required 2 to 3 h. In contrast to inhibition, growth resumed quickly in the recovery test. Re‐growth started after about 10 to 25 min, and recovered to a steady rate after 25 to 40 min following removal of the drugs. In the combined treatment, with only one drug removed, re‐growth only occurred when the second drug was also removed. Cell turgor, hydraulic conductivity (Lp), and membrane potential (Em) were measured with the T‐EP probe in the drug treatments. The possible involvement of changes in cell turgor, Lp and pH of walls and of cytoplasm in inhibition of growth were excluded. Disruption of MF and MT in internodal cells of Nitellopsis by CD and oryzalin were confirmed under laser‐scanning confocal microscopy (Bio‐Rad MRC‐1024). The results showed that the maintenance of growth rate of internodal cells of Nitellopsis required both intact MF and MT.
Epitaxial growth of ErAs on (100)GaAs
Authors: Palmstro/m C. J. , Tabatabaie N. , Allen S. J.
Published: July 2002

Successful growth of (100)ErAs single-crystal films on (100)GaAs has been demonstrated. Reflection high-energy electron diffraction, low-energy electron diffraction (LEED), and Rutherford backscattering with channeling indicate single-crystal growth. LEED from the ErAs shows a (1×1) structure. Overgrowth of GaAs on ErAs is found to be difficult due to the GaAs not wetting the ErAs surface and hence resulting in island growth. For a 150-Å-thick film metallic behavior is observed with resistivities 17 and 70 μΩ cm at 1.5 K and room temperature, respectively. Low-temperature Hall measurements show the conduction to be dominated by electrons with an effective n-type mobility in the range 360 cm2/V s at 1.35 K.
Effect of local alloy disorder on emission kinetics of deep donors (D
X centers) in AlxGa1−xAs of low Al content
Authors: Mooney P. M. , Theis T. N. , Wright S. L.
Published: July 2002

We report measurements by deep level transient spectroscopy of electron emission from the deep donor level (DX center) in Si-doped GaAs and AlxGa1−xAs of very low Al content. For the first time, discrete emission rates corresponding to different local configurations of Ga and Al atoms around the Si donor are resolved. The large change in emission kinetics previously observed between GaAs and AlxGa1−xAs (x≥0.14) is thus shown to arise from the local alloy disorder which is absent in GaAs.
Mechanical and superconducting properties of sintered composite YBa2Cu3O7−δ tape on a silver substrate
Authors: Singh J. P. , Shi D. , Capone D. W.
Published: July 2002

Flexible sintered composite YBa2Cu3O7−δ tapes on a silver substrate have been fabricated by the tape casting technique followed by appropriate sintering. The sintered composite tape can be bent into an arc of a 27-mm-diam circle without breaking. This represents approximately 2% strain, as compared with a typical YBa2Cu3O7−δ superconductor material without silver, which fractures at a strain of ∼0.1–0.2%. The silver addition does not adversely affect the superconducting properties of the composite.
Heteroepitaxial growth of InN by microwave-excited metalorganic vapor phase epitaxy
Authors: Wakahara Akihiro , Yoshida Akira
Published: July 2002

Epitaxial layers of InN films were grown onto (0001) α-Al2O3 substrates in the temperature range of 400–600 °C by microwave-excited metalorganic vapor phase epitaxy using (CH3)3In and N2. Specular surface was obtained at a low substrate temperature (<500 °C) with a relatively high microwave power (>100 W). From reflection high-energy electron diffraction analysis, the deposited films were found to be crystalline InN with an orientation relation of (0001) InN//(0001) α-Al2O3. The stoichiometry of the grown films was found to be similar to that reported for bulk InN from electron spectroscopy for chemical analysis.
Carbon implantation in InP
Authors: Pearton S. J. , Chakrabarti U. K. , Abernathy C. R. , Hobson W. S.
Published: July 2002

Carbon implanted into InP at doses between 5×1012 and 5×1014 cm−2, either by itself or with B, Ga, Al, or P coimplantation at room temperature or 200 °C, displays donor activity for all annealing temperatures (600–900 °C; 10 s). Phosphorus coimplantation enhances the donor activation percentage over carbon-only implantation, while coimplants of B, Ga, and Al reduce the donor activity. Peak carrier concentrations of 3×1019 cm−3 were obtained for C+P implantation at a dose of 5×1014 cm−2, followed by annealing at 700 °C for 10 s. Annealing at >700 °C leads to a reduction in net donor density through carbon site switching to produce self-compensation. The C diffusivity is estimated to be less than 2.5×10−14 cm−2 s−1 at 800 °C.
InGaAs/InAsPSb diode lasers with output wavelengths at 2.52 μm
Authors: Martinelli Ramon U. , Zamerowski Thomas J.
Published: July 2002

We have studied InGaAs/InAsPSb double heterojunction, oxide stripe lasers grown by hydride vapor phase epitaxy. At 80 K the threshold current density is 0.4 kA/cm2, the staturated output power is about 4 mW, and the differential quantum efficiency just above threshold is 20% per facet. The output wavelength increases from 2.44 μm at 80 K to 2.52 μm at 190 K. A layer of compositionally graded InGaAs accommodates the 2% lattice mismatch between the InP substrate and the laser structure. The operating characteristics of these lasers are compared with those of InGaAs/InAsP lasers. Their improved performance results from the better electrical and optical confinement of the InAsPSb cladding layers.
All solid-state cw passively mode-locked Ti:sapphire laser using a colored glass filter
Authors: Sarukura Nobuhiko , Ishida Yuzo , Yanagawa Tsutomu , Nakano Hidetoshi
Published: July 2002

All solid-state cw passive mode locking of a Ti:sapphire laser is accomplished using a colored glass filter, instead of an organic dye, as a saturable absorber. The tuning range is remarkably wide (785–855 nm), and 2.7 ps pulses are obtained directly from the cavity.
Electron transport of inhomogeneous Schottky barriers
Authors: Tung R. T.
Published: July 2002

A novel approach is presented which leads to analytic solutions to the potential and the electron transport through inhomogeneous Schottky barriers. The existence of barrier height nonuniformities is shown to provide a simple explanation of the following abnormal experimental results, routinely observed from various Schottky barriers: greater-than-unity ideality factors, the T0 effect, the ‘‘soft’’ reverse characteristics, and the dependence of barrier height on the technique of measurement.
Giant magnetoresistance in antiferromagnetic Co/Cu multilayers
Authors: Parkin S. S. P. , Li Z. G. , Smith David J.
Published: July 2002

We report giant values of saturation magnetoresistance in sputtered antiferromagnetic Co/Cu multilayers containing thin Co and Cu layers 8–10 Å thick. We discuss the key importance of the buffer layer in controlling the growth of flat Co and Cu layers. As shown by cross-section transmission electron microscopy high-quality structures are found for growth on Fe buffer layers. Such structures display saturation magnetoresistance at 300 K of more than 65% with saturation fields of ≂10 kOe. These values are several times larger than previously found for any magnetic material at room temperature.
Nanosecond switching of thin ferroelectric films
Authors: Larsen P. K. , Kampschöer G. L. M. , Ulenaers M. J. E. , Spierings G. A. C. M. , Cuppens R.
Published: July 2002

The switching time (ts) for polarization reversal in ferroelectric films of PbZr0.53Ti0.47O3 and La-substituted PbTiO3 has been investigated. The films were prepared by spin-on and metalorganic decomposition followed by processing into ferroelectric capacitors having electrode areas ranging from 9 to 50 000 μm2. Pulse measurements show that under all our experimental conditions ts is instrumentally limited and that therefore the true switching time is smaller than the experimental resolution of 1.8 ns. This very fast polarization reversal can be explained by a nucleation-rate-controlled switching mechanism.
Fermi edge singularity and screening effects in the absorption and luminescence spectrum of Si δ-doped GaAs
Authors: Wagner J. , Fischer A. , Ploog K.
Published: July 2002

We have investigated single Si δ-doped layers in GaAs by photoluminescence and photoluminescence excitation spectroscopy (PLE). When the photogenerated holes are confined by GaAs/AlxGa1−xAs heterointerfaces placed at either side of the doped layer strong radiative recombination is observed from the quasi-two-dimensional electron gas associated with the δ-doping spike. The low-temperature absorption spectrum involving spatially direct transitions, which was measured by PLE, shows a well resolved enhancement at the Fermi edge. The energy position of the absorption edge is found to be independent of the excitation intensity. The peak energy of the band-to-band emission spectrum, in contrast, which involves spatially indirect transitions, shows a shift to higher energies with increasing excitation intensity due to the screening of the space-charge-induced potential by photogenerated carriers.
Enhanced quantum interference effects in parallel Josephson junction arrays
Authors: Miller J. H. , Gunaratne G. H. , Huang J. , Golding T. D.
Published: July 2002

We have calculated the total critical current as a function of applied magnetic flux for a superconducting interferometer consisting of many Josephson junctions in parallel. An enhancement and narrowing of the periodic principal maxima in the critical current versus flux characteristic is predicted as the number of junctions in parallel increases, even when the effects of finite self- and mutual inductances and nonuniformity of the junction critical currents are included in the calculations. The possible application of the superconducting quantum interference grating, or SQUIG, for the detection of magnetic flux is discussed.