bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitric oxide synthase is present in the cerebrospinal fluid of patients with active multiple sclerosis and is associated with increases in cerebrospinal fluid protein nitrotyrosine and S‐nitrosothiols and with changes in glutathione levels
Authors: Calabrese Vittorio , Scapagnini Giovanni , Ravagna Agrippino , Bella Rita , Foresti Roberta , Bates Timothy E. , Giuffrida Stella Anna‐Maria , Pennisi Giovanni
Published: October 2002

Nitric oxide (NO) is hypothesized to play a role in the immunopathogenesis of multiple sclerosis (MS). Increased levels of NO metabolites have been found in patients with MS. Peroxynitrite, generated by the reaction of NO with superoxide at sites of inflammation, is a strong oxidant capable of damaging tissues and cells. Inducible NO synthase (iNOS) is up‐regulated in the CNS of animals with experimental allergic encephalomyelitis (EAE) and in patients with MS. In this study, Western blots of cerebrospinal fluid (CSF) from patients with MS demonstrated the presence of iNOS, which was absent in CSF from control subjects. There was also NOS activity present in both MS and control CSF. Total NOS activity was increased (by 24%) in the CSF from MS patients compared with matched controls. The addition of 0.1 mM ITU (a specific iNOS inhibitor) to the samples did not change the activity of the control samples but decreased the NOS activity in the MS samples to almost control levels. The addition of 1 mM L‐NMMA (a nonisoform specific NOS inhibitor), completely inhibited NOS activity in CSF from control and MS subjects. Nitrotyrosine immunostaining of CSF proteins was detectable in controls but was greatly increased in MS samples. There were also significant increases in CSF nitrate + nitrite and oxidant‐enhanced luminescence in MS samples compared with controls. Additionally, a significant decrease in reduced glutathione and significant increases in oxidized glutathione and S‐nitrosothiols were found in MS samples compared with controls. Parallel changes in NO metabolites were observed in the plasma of MS patients, compared with controls, and accompanied a significant increase of reduced glutathione. These data strongly support a role for nitrosative stress in the pathogenesis of MS and indicate that therapeutic strategies focussed on decreasing production of NO by iNOS and/or scavenging peroxynitrite may be useful in alleviating the neurological impairments that occur during MS relapse. © 2002 Wiley‐Liss, Inc.
Calpain and calpastatin expression in primary oligodendrocyte culture: Preferential localization of membrane calpain in cell processes
Authors: Ray Swapan K. , Neuberger Timothy J. , Deadwyler Gail , Wilford Gloria , DeVries George H. , Banik Naren L.
Published: October 2002

The cellular localization of calpain is important in understanding the roles that calpain may play in physiological function. We, therefore, examined calpain expression, activity, and immunofluorescent localization in primary cultures of rat oligodendrocytes. The mRNA expression of m‐calpain was 64.8% (P = 0.0033) and 50.5% (P = 0.0254) higher than that of μ‐calpain and calpastatin, respectively, in primary culture oligodendrocytes. The levels of mRNA expression of μ‐calpain and calpastatin were not significantly different. As revealed by Western blotting, cultured oligodendrocytes contained a 70 kD major band identified by membrane m‐calpain antibody, a 80 kD band recognized by cytosolic m‐calpain antibody, and calpastatin bands ranging from 45 to 100 kD detected by a calpastatin antibody. Calpain activity in oligodendrocytes was determined by Ca2+‐dependent 71.2% degradation of endogenous myelin basic protein compared with control; this activity was inhibited significantly (P = 0.0111) by EGTA and also substantially by calpeptin. Localization of calpain in cultured oligodendrocytes revealed strong membrane m‐calpain immunofluorescence in the oligodendrocyte cell body and its processes. In contrast, the cytosolic antibody stained primarily the oligodendrocyte cell body, whereas the processes were stained very weakly or not at all. These results indicate that the major form of calpain in glial cells is myelin (membrane) m‐calpain. The dissimilar localization of cytosolic and membrane m‐calpain may indicate that each isoform has a unique role in oligodendrocyte function. © 2002 Wiley‐Liss, Inc.
Expression of glutamate receptor subtypes in the spinal cord of control and mnd mice, a model of motor neuron disorder
Authors: Mennini Tiziana , Bigini Paolo , Ravizza Teresa , Vezzani Annamaria , Calvaresi Novella , Tortarolo Massimo , Bendotti Caterina
Published: October 2002

We studied the expression and distribution of glutamate receptor subtypes in the spinal cord of mnd mice, a model of motor neuron disorders and neuronal ceroid lipofuscinosis, and control mice using immunocytochemistry and in situ hybridization. The constitutive subunit of the NMDA ionotropic glutamate receptor, NMDAR1, was expressed in all neurons of the grey matter and was not modified in the spinal cord of mnd mice in either its normal or phosphorylated form. The immunoreactivity of GluR2, but not its mRNA, was increased mainly in the substantia gelatinosa both in presymptomatic and in 8‐month‐old symptomatic mice, suggesting compensatory changes aimed at reducing the Ca2+ permeability of the receptor channel. In spinal cord of mnd mice, mRNA, and protein levels of GluR3 were low only at the symptomatic stage, possibly as a consequence of motor neuron dysfunction. This was not due to motoneuron degeneration, because the number of choline acetyltransferase (ChAT) immunopositive lumbar motor neurons and the ChAT activity in the spinal cord and hind leg muscles of symptomatic mnd mice were no different from control mice. GluR4 mRNA was increased throughout the grey matter, presumably in relation to the marked microglia activation reported in the grey matter of the lumbar spinal cord in mnd mice. These changes in ionotropic glutamate receptors may alter glutamatergic neurotransmission and play some role in the pathology of mnd mice. © 2002 Wiley‐Liss, Inc.
Modeling Alzheimer's disease immune therapy mechanisms: Interactions of human postmortem microglia with antibody‐opsonized amyloid beta peptide
Authors: Lue Lih‐Fen , Walker Douglas G.
Published: October 2002

The induction of an antibody response to amyloid beta (Aβ) peptide has become a strategy for the treatment of Alzheimer's disease (AD). This has proven effective in reducing the plaque burden in transgenic mice that develop Aβ plaques similar to human AD patients. The mechanism for enhanced clearance of Aβ is partly due to the interaction of immunoglobulin Fcγ receptor‐expressing microglia and specific antibody‐opsonized Aβ deposits. This interaction can stimulate Fcγ receptor‐mediated phagocytosis, but also results in inflammatory activation of these cells. Consequently, interaction of microglia with antibody‐antigen complexes could exacerbate the existing inflammation in the brains of AD patients. In this study, we used substrate‐bound Aβ and cultured human microglia from AD and non‐demented cases to model interaction of microglia and antibody‐opsonized plaques in AD brains. Enhanced production of tumor necrosis factor‐α, macrophage colony stimulating factor, interleukin‐10, and superoxide ions was detected. We also demonstrated enhanced uptake of opsonized Aβ by microglia, which was reduced significantly in the presence of excess IgG, indicative of the involvement of Fcγ receptor‐mediated mechanisms. Human microglia were shown in this study to express mRNA for Fcγ receptors I, IIa, IIb, and III. The expression of Fcγ receptor II was augmented by proinflammatory stimulation. These results suggest that initial interactions of human microglia with antibody‐opsonized amyloid could result in increased inflammation. The consequence of this on inflammatory pathology in AD brains needs to be considered before immunization is used as a strategy for treating AD. © 2002 Wiley‐Liss, Inc.
Effects of intrauterine inflammation on developing rat brain
Authors: Bell Michael J. , Hallenbeck John M.
Published: October 2002

Damage to the white matter in the brain during development can lead to cerebral palsy (CP), a heterogeneous group of clinical syndromes that results in life‐long disorders of movement and posture. Periventricular leukomalacia (PVL) is a pathological process within the white matter characterized by oligodendrocyte loss and is associated with the development of CP. Clinically, CP and PVL are associated with intrauterine infection and inflammation, but mechanisms involved are not well understood. We developed a model of intrauterine inflammation in Lewis and Fischer 344 rats to study the effects of intrauterine inflammation on developing glia. Pregnant rats were intracervically injected with lipopolysaccharide (LPS) at 15 days of gestation (E15) and a dose of LPS that caused low fetal mortality was determined. At E20, treated fetuses had increased TUNEL+ nuclei and tumor necrosis factor (TNF)‐α‐immunoreactive areas within the brains. In a second series of animals allowed to survive until postnatal day 21 (PND 21), immunostaining was performed against several glial markers. Staining for the oligodendrocyte‐specific proteins 2′, 3′‐cyclic nucleotide phosphodiesterase (CNP) and myelin proteolipid protein (PLP) was decreased in treated pups compared to shams within the corpus callosum, a white matter structure used as a representative area of developing white matter. Treated pups had activated astrocytes lining cerebral blood vessels, as observed by glial fibrillary acidic protein (GFAP) staining, while sham pups did not. Activated microglia were not detected using OX42 as a cell marker. Our model of intrauterine inflammation causes increased TUNEL and TNF‐α staining early after injury, suggesting increased apoptotic cell death, possibly by cytokine‐related mechanisms. © 2002 Wiley‐Liss, Inc.
Type‐2 astrocyte‐like cells are more resistant than oligodendrocyte‐like cells against non‐N‐methyl‐D‐aspartate glutamate receptor‐mediated excitotoxicity
Authors: Yamaya Yoko , Yoshioka Akira , Saiki Shinji , Yuki Natsuko , Hirose Genjiro , Pleasure David
Published: October 2002

Glutamate causes excitotoxicity via non‐N‐methyl‐D‐aspartate (NMDA) glutamate receptors (GluR) in oligodendrocytes. Because both oligodendrocytes and type 2 astrocytes are differentiated from oligodendrocyte‐type 2 astrocyte (O‐2A) progenitor cells, we investigated whether astrocytes are also vulnerable to non‐NMDA GluR‐mediated excitotoxicity. For these studies, oligodendrocyte‐like cells (OLC) and type 2 astrocyte‐like cells (2ALC) were derived from CG‐4 cells, an immortalized rat O‐2A progenitor cell line. About 50% of 2ALC were positive for glial fibrillary acidic protein and 90% were positive for A2B5, verifying that these cells have an type 2 astrocytic phenotype. A 24‐hr exposure of OLC to 2 mM kainate, an activator of non‐NMDA GluR, caused cell damage as shown by the release of lactate dehydrogenase. The extent of kainate‐induced OLC damage was increased by cyclothiazide. In contrast, exposure of 2ALC to 2 mM kainate alone did not induce injury, though mild 2ALC injury was elicited by exposure to 2 mM kainate plus 100 μM cyclothiazide. Furthermore, we found that the kainate induced Ca2+ uptake by 2ALC was 27.5% of that induced by kainate in OLC. Finally, both OLC and 2ALC expressed non‐NMDA GluR subunit mRNAs, including GluR2, GluR3, GluR4, GluR6, GluR7, KA1, and KA2, but quantitative Western blot analysis revealed higher immunodetectable GluR2 and lower immunodetectable GluR3 and GluR4 in 2ALC than in OLC. Together, these results suggest that astrocytes are relatively resistant to non‐NMDA GluR‐mediated excitotoxicity because they have a higher expression of GluR2 and lower expression of GluR3 and GluR4. © 2002 Wiley‐Liss, Inc.
In vivo model for visualizing flap microcirculation of ischemia‐reperfusion
Authors: Ichioka Shigeru , Minh Trinh Cao , Shibata Masahiro , Nakatsuka Takashi , Sekiya Naomi , Ando Joji , Harii Kiyonori
Published: October 2002

Since ischemia‐reperfusion injury continues to be a major problem in reconstructive microsurgery, improvement of experimental models is still desirable. We developed a model that allows direct visualization of flap microcirculation in mice by intravital microscopic techniques. A newly designed skinfold chamber was installed on the dorsum of mice, and microcirculation was inspected with an intravital microscope. An island flap, nourished by the deep circumflex iliac arteries, was elevated after implantation of the chamber, allowing visualization of the microcirculation in the island flap. The island flap was exposed to global ischemia by clamping the pedicles, and the clamps were then released to allow reperfusion. Various microcirculatory responses induced by ischemia‐reperfusion were visualized. This model accurately simulated the clinical situation in reconstructive surgery and successfully realized chronic visualization of the flap microcirculation in vivo. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:304–310 2002
Absorptive properties of synovium harvested from the carpal tunnel
Authors: Sud Vipul , Tucci Michelle A. , Freeland Alan E. , Smith William T. , Grinspun K.
Published: October 2002

Ischemia‐induced reperfusion injury seems to play an important role in the pathophysiology of “idiopathic” carpal tunnel syndrome (CTS). The common final pathway in this developmental sequence is thought to be an intermittent increase in interstitial pressure, leading to degenerative changes in the flexor tenosynovium and fibrotic changes in the perineural tissue. We hypothesize that this concurrently leads to alteration in the physical properties of the synovium, leading to its rapid and persistent swelling. A prospective study was conducted on synovial tissue obtained from 27 CTS patients. The in vitro synovial absorption rate of CTS patients was significantly higher in the first hour compared to controls (n = 7). This difference was maintained up to 5–6 h, albeit at a slower rate. Rapid absorption and retention of fluid by the synovium led to increased interstitial pressure and nerve compression, resulting in early and persistent manifestation of symptoms in sensitized patients. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:316–319 2002
Monitoring free flaps using laser‐induced fluorescence of indocyanine green: A preliminary experience
Authors: Holm C. , Tegeler J. , Mayr M. , Becker A. , Pfeiffer U.J. , Mühlbauer W.
Published: October 2002

In a prospective, clinical study, the clinical utility of indocyanine green for intraoperative monitoring of free tissue transfer was evaluated. The study comprised 20 surgical patients undergoing elective microsurgical procedures. Indocyanine green angiography was performed intraoperatively, immediately after flap inset, and the operating team was blind to the fluoremetric findings. Thereafter, postoperative monitoring was done exclusively by clinical examination (color, temperature, time for recapillarization, and bleeding after puncture). Final outcome was compared with results of perioperative indocyanine (ICG)‐imaging, and classified either as total flap loss, partial flap loss, or successful tissue transplantation. A total of 2 (10%) complications was recorded, and included one partial and one total flap loss. Both complications were detected by intraoperative ICG imaging. Another case of intraoperative subclinical arterial spasm at the place of microvascular anastomosis was revealed by dynamic ICG‐videography. This flap did not develop postoperative complications. In conclusion, evaluation of perfusion by ICG imaging is feasible in all kinds of microsurgical flaps, irrespective of the type of tissue. Even though not meeting all the criteria of an ideal monitoring device, significant additional information can be obtained. In this study, cases with arterial spasm, venous congestion, and regional hypoperfusion were revealed by intraoperative ICG‐videography. There was a strong correlation between intraoperative findings and clinical outcome. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:278–287 2002
Neurotrophins and their receptors in early axonal regeneration along muscle‐vein‐combined grafts
Authors: Pagnotta Alessia , Tos Pierluigi , Fornaro Michele , Gigante Antonio , Geuna Stefano , Battiston Bruno
Published: October 2002

Experimental and clinical studies have shown that a vein segment filled with skeletal muscle used to bridge a peripheral nerve defect (muscle‐vein‐combined graft) leads to good nerve repair. However, the molecular basis of the nerve fiber regeneration process along this type of graft still remains to be elucidated. The aim of this study was to verify the expression of two neurotrophins, nerve growth factor (NGF) and brain‐derived neurotrophic factor (BDNF), as well as their receptors, trkA and p75, in an early stage of axonal regeneration in muscle‐vein‐combined grafts. Severed rat sciatic nerves were repaired by means of 1‐cm‐long muscle‐vein‐combined grafts and withdrawn immediately after surgery (control grafts) and 5 days after surgery. Longitudinal sections of grafts were immunostained by means of the following antibodies: anti‐NGF, anti‐BDNF, anti‐trkA, and anti‐p75. An anti‐glial fibrillar acid protein (anti‐GFAP) antibody was used to recognize Schwann cells. Results showed the presence of a number of GFAP‐positive Schwann cells inside the muscle‐vein grafts. Many of these cells reacted for NGF, BDNF, and p75, but not trkA. In control grafts, i.e., immediately after surgery, no immunostaining was detected for any of the antibodies used in this study. These observations suggest that, very early after surgery, the muscle‐vein‐combined graft offers to growing axons an environment particularly favorable for regeneration, providing us with a possible explanation for the efficacy of this grafting technique for peripheral nerve repair. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:300–303 2002
Effect of long‐term application of epinephrine on rat skin vasculature: Experimental study
Authors: Karacaoğlu Ercan , Çermik Hakan , Yurdun Türkan , Zienowicz Richard J.
Published: October 2002

As a potent vasoconstrictor, epinephrine is used ubiquitously in plastic surgery. It is typically delivered subcutaneously in very low concentrations over a brief time interval. We are aware of no reports describing the long‐term release of epinephrine as an independent agent to the soft tissues for the purpose of causing prolonged local vasoconstriction. This study was designed to address two goals: first, to investigate the effect of long‐term local release of epinephrine from a drug delivery system on rat abdominal skin vasculature; secondly, to evaluate the pharmacological properties of this drug delivery system (DDS). Thirty male Sprague‐Dawley rats, weighing 300–400 g, were included in the study. Animals were subdivided into two groups of 15 each. Group A (control group) and Group B (experimental group) were treated with saline and epinephrine‐loaded microspheres (msps), respectively. The manufacturing process and formulation studies of the DDS are described. In vivo assays revealed a 7‐day sustained release of epinephrine. After 7 days, neither residual nor supraphysiologic release of epinephrine was shown with high‐performance liquid chromatography (HPLC). Histological studies with hematoxylin‐eosin and periodic acid Schiff revealed a statistically significant increase in number of vessels as well as their diameter and wall thickness (P <0.05). Epinephrine release via this msp/DDS predictably induces local vasoconstriction over a time sequence known to be optimally associated with hypoxia and promotion of vascular augmentation. This model can be valuable in sustaining hemostasis during long‐lasting (more than a few hours) surgical procedures by its long‐acting vasoconstructive effect. The system's ability to intentionally cause vascular augmentation also bodes great potential in flap and graft surgery. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:288–294 2002
Reconstruction of peripheral nerves using acellular nerve grafts with implanted cultured Schwann cells
Authors: Frerichs Onno , Fansa Hisham , Schicht Christoph , Wolf Gerald , Schneider Wolfgang , Keilhoff Gerburg
Published: October 2002

The bridging of nerve gaps is still one of the major problems in peripheral nerve surgery. The present experiment describes our attempt to engineer different biologic nerve grafts in a rat sciatic nerve model: cultured isogenic Schwann cells were implanted into 2‐cm autologous acellular nerve grafts or autologous predegenerated nerve grafts. Autologous nerve grafts and predegenerated or acellular nerve grafts without implanted Schwann cells served as controls. The regenerated nerves were assessed histologically and morphometrically after 6 weeks. Predegenerated grafts showed results superior in regard to axon count and histologic appearance in comparison to standard grafts and acellular grafts. The acellular nerve grafts showed the worst histologic picture, but axon counts were in the range of standard grafts. The implantation of Schwann cells did not yield significant improvements in any group. In conclusion, the status of activation of Schwann cells and the stadium of Wallerian degeneration in a nerve graft might be key factors for regeneration, rather than total number of Schwann cells. Predegenerated nerve grafts are therefore superior to standard grafts in the rat model. Acellular grafts are able to bridge nerve gaps of up to 2 cm in the rat model, but even the addition of cultivated Schwann cells did not lead to results as good as in the group with autologous nerve grafts. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:311–315 2002
Replantation of a crush amputation of distal tibia followed by lengthening with Ilizarov circular external fixator: Two‐year follow‐up
Authors: Ni̇şanci Mustafa , Er Ergin , Yildiz Cemil , Türegün Murat , Atealp Sabri , Şengezer Mustafa
Published: October 2002

A 20‐year‐old male sustained a severe crush injury to his left leg, resulting in amputation of the foot at the level of the distal tibia. Despite 12‐h warm ischemia, replantation was attempted after radical debridement, bone shortening, and proximal fasciotomies. The replanted part survived totally. Four months later, a 13‐cm shortness of the extremity was managed by 10‐cm lengthening with distraction osteogenesis, using Ilizarov's circular external fixator and by means of a special shoe. Two‐year follow‐up of the patient revealed acceptable functional and sensorial recovery. Success of replantation despite the excessive warm‐ischemia time was attributed to the sparse muscle content of the distal tibia and foot. Fasciotomies performed on the proximal segment of the leg ensured the patency of anastomoses by maintaining adequate blood flow distally despite increasing edema after the crush injury. Debridement and bone shortening at the proximal stump eliminated the vein and nerve grafts to bridge the gap. In conclusion, considering the functional outcome of our case, replantation of distal parts of a lower extremity should be attempted first, even if the nature of the injury is unfavorable and the ischemia time is longer than the documented ischemia‐tolerance. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:295–299 2002
Health care needs diabetes model — description of a practical tool
Authors: Bottomley J , Duggan A , Williams R
Published: October 2002

Primary care organisations (PCOs) have a responsibility to deliver quality services to meet health needs. This responsibility, in relation to services for people with diabetes, will be further clarified when the Diabetes National Service Framework (NSF) is published. This paper describes the first example of a practical model, the health care needs assessment (HCNA)—diabetes model, in use in the NHS today, which is interactive, flexible and evidence based and which is being used to improve services for designated populations.

The HCNA—diabetes model provides a population focus for the provision of services to meet local healthcare needs. It compares local provision of care to national standards and allows the option of designing a bespoke model of care for the selected population. The implication of this in terms of resource use, costs and staffing levels required to provide the service (of either current care, a model of care, or ‘your own model of care’) is described.

The model can be customised to reflect local circumstances or be modified to reflect health needs in other countries, by overriding the default data with local data.

The authors believe the HCNA—diabetes model will help PCOs manage the planning of quality services, now and following the publication of the NSF, to meet the needs of selected populations of people with diabetes. Copyright © 2002 John Wiley & Sons, Ltd.
Short‐term antioxidant supplementation reduces oxidative stress in elderly patients with type 2 diabetes mellitus—a pilot study
Authors: Nuttall SL , Martin U , Kendall MJ , Dunne F
Published: October 2002

Aims

The aim of this pilot study was to determine what dose of which antioxidants might be studied in clinical trials by assessing the impact of vitamin (C and E) supplementation on markers of oxidative stress and LDL subfractions in patients with type 2 diabetes mellitus.

Methods

Nine elderly patients with type 2 diabetes took a moderate dose combination of vitamins C (500 mg) and E (400 IU) for 4 weeks. Following a 4 week washout, the patients had a further 4 weeks of supplementation with a higher dose combination of vitamins C (1000 mg) and E (800 IU). Blood was sampled pre‐ and post‐supplementation for vitamin E by high‐performance liquid chromatography (HPLC), total antioxidant capacity by enhanced chemiluminescence, total cholesterol and lipid hydroperoxides by colour spectrophotometry and LDL subfraction profile by disc polyacrylamide gel electrophoresis.

Results

Vitamin E was increased, after the moderate dose combination (59.8 ± 6 versus 36.4 ± 4 µmol/L, p < 0.001) and increased further by the higher dose (72.7 ± 11 versus 30.8 ± 5 µmol/L, p < 0.001). Total antioxidant capacity was significantly increased above baseline after both doses (508.2 ± 33 versus 436.4 ± 31, p < 0.01 (moderate); 519.3 ± 48 versus 440.8 ± 34 µmol/L trolox eq., p < 0.01 (high)). Lipid hydroperoxides were reduced more after the moderate dose combination than after the high dose (6.1 ± 1 versus 12.1 ± 2, p < 0.01; 8.0 ± 1 versus 11.6 ± 1 µmol/L, p < 0.05). LDL subfraction score showed a non‐significant reduction after both periods of supplementation.

Conclusions

This study has demonstrated that supplementation with modest doses of the antioxidant vitamins C and E can significantly increase antioxidant defences and reduce oxidative damage in elderly patients with type 2 diabetes. Copyright © 2002 John Wiley & Sons, Ltd.
Basal insulin—answers from analogues?
Authors: Barnett AH
Published: October 2002

This review discusses the role of basal insulin therapy in the treatment of patients with type 1 and type 2 diabetes in the light of the availability of a new long‐acting analogue, insulin glargine. The critical role of basal insulin therapy is described, together with an overview of current and future basal insulin provision. Copyright © 2002 John Wiley & Sons, Ltd.
An unusual presentation of type 2 diabetes mellitus
Authors: McAulay V , Ibrahim BA , Campbell IW , Nawroz I
Published: October 2002

A 53 year old male was diagnosed as having diabetes mellitus secondary to haemochromatosis. The patient died 27 months after presentation from a hepatoma. Haemochromatosis is reviewed with regard to its clinical presentation, diagnosis, treatment and prognosis. New information with regard to genotypic testing is discussed and screening for haemochromatosis in diabetic subjects and in relatives of patients with diagnosed haemochromatosis is reviewed. Copyright © 2002 John Wiley & Sons, Ltd.
Analysis of a retinal screening database to investigate the relationship between intraocular pressure and diabetic retinopathy
Authors: Barton DM , Daneshvar C , Carrington D , Buch HN , Macleod AF , West TET
Published: October 2002

Aims

To investigate whether there is a relationship between intraocular pressure (IOP) and diabetic retinopathy.

Methods

Retrospective analysis of a retinal screening database of 5838 patients with diabetes compiled over 5 years giving information on 20 091 eye examinations.

Results

Lower mean IOP was associated with the presence of hard exudates alone (p < 0.005) and hard exudates with cotton wool spots (p < 0.001). There was no statistically significant association between IOP and other grades of retinopathy.

Conclusions

The mean IOP reductions observed in exudative retinopathy, although statistically significant, were probably too small to measure conventionally. The effect of low IOP on development of retinopathy may be mediated by higher ocular perfusion pressure, but why this would be specific to exudative disease is unclear. Copyright © 2002 John Wiley & Sons, Ltd.
Forensic evidence collection for sexual assault: a South African perspective
Authors: Martin L.J
Published: November 2002

The incidence of rape in South Africa is approximately 300 per 100 000 women, with a conviction rate of approximately 10% of cases. Poor medical evidence is responsible in part for the low conviction rate. The district surgeon system that was responsible for medico‐legal procedures and examinations is being phased out which has left the examination of sexual offences to all state employed medical practitioners. Lack of training and expertise make the present system untenable. There are several proposals being considered and implemented in the Western Cape Province to address this deficiency, which include the formation of ‘one‐stop centers’, training, and complete evidence collection kits.
Dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) sea surface distributions simulated from a global three‐dimensional ocean carbon cycle model
Authors: Aumont Olivier , Belviso Sauveur , Monfray Patrick
Published: October 2002

A global model for surface dimethylsulfide (DMS) and particulate dimethylsulfoniopropionate (DMSP) (pDMS) distributions is presented. The main goals of this work were to be able to predict the regional distribution of the air‐sea fluxes of DMS and to predict eventually their future evolution with climate change. Diagnostic relationships have been established from data sets obtained during the ALBATROSS and EUMELI cruises carried out in the Atlantic Ocean. These equations nonlinearly relate DMS and pDMSP concentrations to chlorophyll concentrations and to the trophic status of surface waters. This model has been embedded in the global ocean carbon cycle model Institut Pierre et Simon Laplace‐Ocean Carbon Cycle Model version 2 (ISPL‐OCCM2), a simple plankton model coupled to a global three‐dimensional ocean general circulation model. Predicted global distributions and seasonal variations of surface chlorophyll are in good agreement with the observations, except in the equatorial Pacific Ocean and, to a lesser extent, in the Southern Ocean. In these regions, simulated surface chlorophyll concentrations are strongly overestimated, most likely because limitations of the biological production by nutrients like iron or silicate are not considered. The model predicts surface DMS and pDMSP concentrations, which compare reasonably well with the observations. However, in the high latitudes, seasonal variations are underestimated, especially in the Ross and Weddell Seas where observed very elevated concentrations of DMS due to spring and summer blooms of Phaeocystis cannot be reproduced by the model. The global annual flux of DMS predicted by lPSL‐OCCM2 ranges from 17 to 26.7 Tg S yr−1 depending on the formulation for gas exchange coefficient. About one third of this flux is located in the subtropical/subpolar frontal zone of the Southern Ocean, which plays a critical role in the sulfur cycle. Furthermore, model results suggest that the Southern Ocean, south of the Polar Front, could be a rather modest source of DMS for the atmosphere.
Role of rafting in the mechanical redistribution of sea ice thickness
Authors: Babko O. , Rothrock D. A. , Maykut G. A.
Published: October 2002

Ice draft data derived from upward looking sonar observations collected during a Scientific Ice Expeditions (SCICEX) submarine cruise in the Arctic Ocean have been used to test the ice thickness distribution theory of Thorndike et al. [1975]. Two separate ice draft surveys, 40 days apart, were made during the fall of 1996 in a circular Lagrangian region ∼180 km across. Air temperature and deformation data from buoys in the region were used to force an ice thickness distribution model in an effort to reproduce the changes observed over the 40 day interval. Initial tests with an elementary ridging treatment were unsuccessful in predicting the observed change in the ice thickness distribution. The shape of the distribution suggested that both ridging and rafting of ice were involved in the redistribution process. Modifying the theory to include rafting along with ridging resulted in much improved agreement between the modeled and observed ice thickness distributions. This result, taken together with many other field observations, leads us to believe that rafting is an important component of the mechanical redistribution of ice thickness during the fall.
Photobleaching of aquatic dissolved materials: Absorption removal, spectral alteration, and their interrelationship
Authors: Twardowski Michael S. , Donaghay Percy L.
Published: October 2002

Changes in visible region (400–700 nm) absorption spectra of chromophoric dissolved organic matter (CDOM) resulting from natural photobleaching have not been well characterized in aquatic systems. Photobleaching of CDOM absorption and the resultant changes in the exponential spectral slope in the visible domain are documented in a coastal fjord. Measurements of spectral CDOM absorption were made with a WET Labs ac‐9 in situ and in surface water incubated in UV‐transparent Tedlar bags at 1 m for 6 days. The exponential slope of the absorption spectrum between 412–560 nm increased as a function of radiation dosage in the first 72 h of the incubations. Higher spectral slope values were observed in surface waters relative to bottom waters, in agreement with our experimental results. The extent to which a CDOM absorption spectrum altered by photobleaching can serve as a signature of the process itself, containing information about absorption loss, was investigated. From these observations, we propose that higher spectral slopes typically associated with oceanic CDOM relative to coastal CDOM may be due to increased cumulative photobleaching as opposed to a shift in the spectral signature of CDOM sources as has been hypothesized.
Deep water in the late Maastrichtian ocean
Authors: D'Hondt Steven , Arthur Michael A.
Published: October 2002

Stable isotopic data from benthic foraminifera indicate the occurrence of at least three deepwater masses in the late Maastrichtian ocean. Given mean oceanic δ18Ow of −1.0‰, the temperature of the coolest intermediate‐depth waters was 5°–7°C, that of the deepest waters was 10°C, and that of the warmest intermediate waters was 13°–15°C. The cool intermediate‐depth water mass probably originated in the high‐latitude Southern Ocean. The deepest waters originated at least partly in the northern Atlantic. The source region for the warmest intermediate‐depth water mass is unknown. Although much of the late Maastrichtian deep water was probably preconditioned for winter sinking by low‐ or middle‐latitude evaporation, no more than ∼11% of late Maastrichtian deep water could have been directly actuated by low‐latitude sea surface evaporation. At least in the southern Atlantic and Indian Oceans, heat transport by upwelling of deep water was not the primary cause of mild sea surface and coastal temperatures.
Development of a modified two‐scale electromagnetic model simulating both active and passive microwave measurements: Comparison to data remotely sensed over the ocean
Authors: Boukabara S. A. , Eymard L. , Guillou C. , Lemaire D. , Sobieski P. , Guissard A.
Published: October 2002

Spaceborne microwave remote sensing allows the determination of oceanic and atmospheric parameters. Operational payloads such as ERS‐1 and ERS‐2 and TOPEX/Poseidon as well as missions such as Jason (from NASA–Centre National d'Etudes) or Envisat (from the European Space Agency), have contained or contain paired microwave instruments looking at the nadir direction. This combination consists of microwave radiometers and a radar‐altimeter. For the frequencies chosen in oceanographic satellite payloads, the active mode signal is mostly dependent on the surface state through its reflectivity and thus used for the near‐surface wind speed retrieval. The active mode can also be attenuated by the atmosphere. On the other hand, the passive mode is related to the surface emissivity and the atmospheric radiation through the radiative transfer equation. Until now, the oceanic and atmospheric parameters have been retrieved separately, the latter being used to correct radar measurements. However, the reflectivity and the emissivity of a target are not independent quantities; hence the synergistic use of these two kinds of microwave measurements should allow one to improve the retrieval quality of the sea and atmosphere parameters. For this purpose, a unified model has been developed for the simulation of both the microwave backscattering coefficient σ° (active measurement) and the microwave emissivity, an important factor for the brightness temperature TB simulation, for every configuration (incidence angles, frequency, polarizations), taking into account the fact that the reflectivity and the emissivity are complementary to unity. The atmospheric absorption is computed following a widely used model from the literature. This paper gives a description and a first attempt of validation of this approach through a comparison with real data. The performance of the model is assessed by comparing the simulations to both brightness temperatures and backscattering coefficients from ERS‐1 and TOPEX/Poseidon's instruments during the SEMAPHORE experiment, over a two‐month period.
A fast algorithm based on the domain decomposition method for scattering analysis of electrically large objects
Authors: Yin Lei , Hong Wei
Published: October 2002

By combining the finite difference (FD) method with the domain decomposition method (DDM), a fast and rigorous algorithm is presented in this paper for the scattering analysis of extremely large objects. Unlike conventional methods, such as the method of moments (MOM) and FD method, etc., the new algorithm decomposes an original large domain into small subdomains and chooses the most efficient method to solve the electromagnetic (EM) equations on each subdomain individually. Therefore the computational complexity and scale are substantially reduced. The iterative procedure of the algorithm and the implementation of virtual boundary conditions are discussed in detail. During scattering analysis of an electrically large cylinder, the conformal band computational domain along the circumference of the cylinder is decomposed into sections, which results in a series of band matrices with very narrow band. Compared with the traditional FD method, it decreases the consumption of computer memory and CPU time from O(N2) to O(N/m) and O(N), respectively, where m is the number of subdomains and Nis the number of nodes or unknowns. Furthermore, this method can be easily applied for the analysis of arbitrary shaped cylinders because the subdomains can be divided into any possible form. On the other hand, increasing the number of subdomains will hardly increase the computing time, which makes it possible to analyze the EM scattering problems of extremely large cylinders only on a PC. The EM scattering by two‐dimensional cylinders with maximum perimeter of 100,000 wavelengths is analyzed. Moreover, this method is very suitable for parallel computation, which can further promote the computational efficiency.
Two‐scale models for rough surface scattering: Comparison between the boundary perturbation method and the integral equation method
Authors: Lemaire David , Sobieski Piotr , Craeye Christophe , Guissard Albert
Published: October 2002

This paper presents a comparison between two models for rough surface scattering computations: the boundary perturbation method (BPM) and the integral equation method (IEM). They differ in two fundamental aspects: the method used to compute the electric and magnetic fields on the surface and the surface information required for the computation. The two approaches lead analytically to the same solution in the two asymptotic cases of very large and very small vertical displacements, with no intermediate scales. For a composite surface the solution of the BPM is expressed as the sum of two terms, while a series development up to higher orders can be formulated with the IEM. In this paper, the comparison is restricted to composite surfaces and, particularly, to the ocean surface. After presenting a method for the two‐scale decomposition of a rough surface, which satisfies the constraints of the electromagnetic model for each scale, we compute the scattering by the ocean surface using both models for various instrumental configurations and surface conditions. We show that considering the accuracy of usual radar measurements and under the assumptions made for the development of the models, both methods give very similar results. Since the BPM is based on a simple physical argument and appears to be more efficient than the two‐scale IEM with regard to the computation time, the BPM should be preferred for ocean‐like rough surfaces.
Modeling the dissolution of settling CaCO3 in the ocean
Authors: Jansen Heiko , Zeebe Richard E. , Wolf‐Gladrow Dieter A.
Published: October 2002

The production, transport, and dissolution of carbonate shells plays an important role in the global carbon cycle. For instance, these processes affect the ocean's CO32− concentration, which, on glacial‐interglacial timescales, is involved in the regulation of atmospheric pCO2. The saturation state of the ocean with respect to calcium carbonate suggests that any dissolution of calcium carbonate takes place not in the water column but at the seafloor. On the other hand, several authors suggest that a significant part of the dissolution takes place in the upper part of the water column. In the present paper, a simple model is presented to investigate under which circumstances dissolution of calcium carbonate in the water column may be plausible. Our analysis also includes dissolution facilitated by CO2 release from organic carbon remineralization, which may generate a microenvironment that is undersaturated with respect to CaCO3. In marine snow aggregates, however, respiration‐driven dissolution is shown to be insignificant due to the size and settling velocities of the aggregates. With respect to aragonite, dissolution in the water column attributable to the bulk saturation state alone is significant and may well contribute to the alkalinity maximum in the undersaturated intermediate waters of the North Pacific Ocean. The suggested large loss of calcium carbonate dissolved in the water column (60–80% of CaCO3 production), however, cannot be explained by the mechanisms investigated here.
Fluxes of CH4, CO2, and N2O in hydroelectric reservoirs Lokka and Porttipahta in the northern boreal zone in Finland
Authors: Huttunen Jari T. , Väisänen Tero S. , Hellsten Seppo K. , Heikkinen Mirja , Nykänen Hannu , Jungner Högne , Niskanen Arto , Virtanen Markku O. , Lindqvist Ossi V. , Nenonen Olli S. , Martikainen Pertti J.
Published: October 2002

Concentrations and fluxes of greenhouse gases methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) were measured during open water conditions in two hydroelectric reservoirs, Lokka and Porttipahta, in the northern boreal zone in Finland. These reservoirs were located on peat and forest soils and were built in 1967 and 1970, respectively. Over 20 years after their flooding, the reservoirs were still largely supersaturated with dissolved CH4and CO2. Measured with floating static chambers, the stations in Lokka released more CH4(means of 5.3–119 mg m−2d−1) during the open water periods in 1994 and 1995 than the stations in Porttipahta (means of 2.5–4.8 mg m−2d−1), measured in 1995. The mean CO2emission rates in Lokka (21–133 mg m−2h−1) and Porttipahta (36–95 mg CO2m−2h−1) were more similar. The chamber measurements could not detect episodic CH4ebullition in Lokka Reservoir, indicated by generally higher CH4fluxes (means of 2.6–660 mg m−2d−1) obtained with bubble gas collectors than with the chambers. The seasonal mean N2O fluxes were generally low, ranging from −89 to 270 μg m−2d−1. There was no clear association between the CH4emissions and the bottom type, including mineral soils and old peat deposits. The flooded vegetation, higher nutrient content, and primary production in the water column rather than old peat could account for the higher CH4emissions from the stations in Lokka. This conclusion is supported by the high content of modern carbon (C) in methane (percent modern C of 92–104%) that was extracted from the sediment of Lokka. The results suggested that if there is a good long‐term availability of phosphorus and nitrogen, the intensive internal C cycle associated with the primary production could maintain high CH4and CO2production for decades, similar to the situation in eutrophied natural lakes.
Exacerbation of erosion induced by human perturbation in a typical Oceania watershed: Insight from 45 years of hydrological records from the Lanyang‐Hsi River, northeastern Taiwan
Authors: Kao Shuh‐Ji , Liu Kon‐Kee
Published: October 2002

High precipitation, steep slopes, small basin areas, and frequent flood events can induce high erosion rates on Oceania islands. These natural characteristics make watersheds much more vulnerable to anthropogenic perturbation. We analyzed long‐term data sets (1950–1994) of suspended sediment loading from two gauges in Lanyang‐Hsi watershed, a typical mountainous river in northeastern Taiwan. Prior to road construction that began in 1957, the annual sediment yield for the downstream gauge near the river mouth was in the range of 730–5400 t km−2 yr−1 with a mean sediment yield of 2800 t km−2 yr−1, which was 18 times higher than the global mean (150 t km−2 yr−1). However, following massive road construction projects, sediment exports increased more than tenfold for the downstream gauge and fortyfold for the upstream gauge at an altitude of 450 m, indicating an exacerbation of erosion induced by human activities. Such conditions of high export lasted for 2–4 years before the sediment yield returned to lower level. From 1957 to 1994 the mean sediment yield for entire watershed went up to 12,800 t km−2 yr−1; ∼75% of that resulted from human perturbation. By comparing the sediment loads from the two gauges we concluded that the extra sediments mainly originated from the upper reach. A huge amount of the sediments apparently had resided in the middle reach; subsequent flood events with enough physical strength may resuspend and sweep the sediments to the sea gradually. Since the Taiwanese rivers represent the extreme conditions in correlation plots for the calculation of sediment export from mountainous rivers, one should exercise great care in distinguishing natural from perturbed conditions when using sediment yield data from Taiwan.