Apolipoprotein A-I promotes the formation of phosphatidylcholine core aldehydes that are hydrolyzed by paraoxonase (PON-1) during high density lipoprotein oxidation with a peroxynitrite donor

High density lipoprotein (HDL) is rich in polyunsaturated phospholipids that are sensitive to oxidation. However, the effect of apolipoprotein A-I and paraoxonase-1 (PON-1) on phosphatidylcholine oxidation products has not been identified. We subjected native HDL, trypsinized HDL, and HDL lipid suspensions to oxidation by the peroxynitrite donor, 3-morpholinosydnonimine. HDL had a basal level of phosphatidylcholine mono- and di-hydroperoxides that increased to a greater extent in HDL, compared with either trypsinized HDL or HDL lipid alone. Phosphatidylcholine core aldehydes, which were present in small amounts, increased 10-fold during oxidation of native HDL, compared with trypsinized HDL (p = 0.004), and 4-fold compared with HDL lipid suspensions (p = 0.0021). In addition, the content of lysophosphatidylcholine increased 300% during oxidation of native HDL, but only 80 and 25%, respectively, during oxidation of trypsinized HDL and HDL lipid suspensions. Phosphatidylcholine isoprostanes accumulated in comparable amounts during the oxidation of all three preparations. Incubation of apolipoprotein A-I with 1-palmitoyl-2-linoleoyl glycerophosphocholine proteoliposomes in the presence of 3-morpholinosydnonimine or apoAI with phosphatidylcholine hydroperoxides resulted in a significant increase in phosphatidylcholine core aldehydes with no formation of lysophosphatidylcholine. We propose that apolipoprotein A-I catalyzes a one-electron oxidation of alkoxyl radicals. Purified PON-1 hydrolyzed phosphatidylcholine core aldehydes to lysophosphatidylcholine. We conclude that, upon HDL oxidation with peroxynitrite, apolipoprotein AI increases the formation of phosphatidylcholine core aldehydes that are subsequently hydrolyzed by PON1.

Myelin/axonal pathology in interleukin-12 induced serial relapses of experimental allergic encephalomyelitis in the Lewis rat

Lewis rats, on recovery from monophasic clinical experimental allergic encephalomyelitis (EAE), can be induced to develop repeated paralytic relapses with a graded reduction in clinical severity following intraperitoneal administration of IL-12. By the time of the third relapse, the number and size of inflammatory cuffs in the spinal cord were reduced with the makeup of the cellular infiltrate shifting to a significantly increased number of B cells. Serum levels of myelin basic protein (MBP)-specific IgG1 and IgG2b were found to rise over time while MBP and MBP peptide-positive macrophages and microglia became evident in perivascular cuffs and in spinal cord parenchyma, indicative of myelin phagocytosis. Axonal death was observed in semithin and EM sections of spinal cord in third relapse animals in association with iNOS and tPA immunostaining throughout gray and white matter. These neurotoxic or excitotoxic agents may contribute to axonal damage directly or indirectly by activated microglia and macrophages, leading to limited damage of the axonal-myelin unit.

Histological pattern of central nervous system neoplasms

OBJECTIVE

To see in a large series of patients the histological pattern of CNS neoplasms and to provide a comprehensive data about the frequency of CNS neoplasms in Pakistani patients and to give a clearer idea about their prevalence.

METHOD

Retrospective study of all consecutive cases of CNS neoplasms diagnosed at The Aga Khan University Hospital (AKUH) between 1st January, 1994 and 31st December, 1999.

SETTING

The section of Histopathology, AKUH, Karachi.

OBSERVATION

Our series included a large number of cases i.e., 1110. There are very few local studies on CNS tumours and none so large. Our data was correlated with published Western and Pakistani data. Glial tumours were the commonest primary CNS neoplasms followed by meningiomas. Among glial tumours, astrocytomas comprised the largest group and the majority were high grade (III and IV) astrocytomas. Percentages of anaplastic oligodendrogliomas and ependymomas were also significant. Male to female ratio was 1.6:1. However, meningiomas were more common in females. Almost half of the CNS tumours in patients 15 years or younger were in the posterior cranial fossa. Metastatic tumours were much lower as compared to the West.

CONCLUSION

Except for the high percentages of anaplastic oligodendrogliomas and ependymomas and the low percentage of metastatic tumours, most of our findings roughly correspond with the published data.

Treatment of bipolar affective disorder in clinical practice

A case note survey of 100 outpatients with a clinical diagnosis of bipolar affective disorder in a UK inner city teaching hospital revealed monotherapy with a mood stabilizer in only 23% of patients, mostly lithium (15%). Overall, 51% of patients were prescribed lithium, 19% carbamazepine and 5% valproate with only 8% receiving a combination of two mood stabilizers. Treatment appeared to be inadequate in 13/51 of patients on lithium, 9/19 of those on carbamazepine and 1/5 of those on valproate. Antipsychotics were used as monotherapy in 20% of patients and combined with a mood stabilizer in 43% of patients. Only 6% of patients were on atypical antipsychotics. These findings suggest that the treatment for many patients does not match recommendations. Clearer evidence on the place of combination mood stabilizers and adjunctive antipsychotics, particularly atypicals is needed in the treatment of bipolar affective disorder.

Abciximab treatment in vitro after aspirin treatment in vivo has additive effects on platelet aggregation, ATP release, and P-selectin expression

To prevent arterial thrombosis, abciximab is administered together with aspirin. However, whether or not there are benefits to combine abciximab with aspirin is not yet well defined. Healthy volunteers were studied for the effect of aspirin + abciximab using sodium arachidonate and adenosine diphosphate (ADP) alone or in combination to induce platelet activation/aggregation. Abciximab produced complete inhibition of platelet aggregation induced with ADP but only 40% inhibition of aggregation induced by 0.75-mmol/l sodium arachidonate. Abciximab added in vitro to platelet-rich plasma (PRP) from platelets from aspirin-treated donors produced an almost complete inhibition of platelet aggregation. Aspirin, and abciximab alone, did not inhibit adenosine triphosphate (ATP) release as thoroughly as aspirin + abciximab did. Abciximab (3-5 microg/ml) produced inhibition of P-selectin expression induced with 5 (from 46.2 +/- 6.0% to 27.4 +/- 7.0%, P=0.002) and 20-micromol/l ADP (from 53.1 +/- 8.1% to 35.1 +/- 11.0%, P=0.019), but no effect was observed when 0.75-mmol/l sodium arachidonate was used (P=0.721). Aspirin diminished P-selectin expression in sodium arachidonate-stimulated platelets (from 77.7 +/- 11.8% to 40.2 +/- 3.6%, P<0.0001) in non-aspirinated and platelets from aspirin-treated donors, respectively. Abciximab (3, 4, and 5 microg/ml) added to platelets from aspirin-treated donors decreased P-selectin expression in platelets stimulated with sodium arachidonate from 40.2 +/- 8.6% to 25.6 +/- 11.5% (P=0.027), to 20.5 +/- 3.5% (P<0.0001), and to 22.5 +/- 1.8% (P<0.0001). We concluded that the antiplatelet effect of abciximab is greatly increased by aspirin.

REDOR NMR on a hydrophobic peptide in oriented membranes

A method is presented for the calculation of REDOR dephasing for specifically labeled membrane-spanning peptides in uniformly aligned lipid bilayers under magic angle oriented sample spinning (MAOSS) conditions. Numerical simulations are performed for dephasing of (13)C signal by (15)N when the labels are placed in an alpha-helical peptide at the carbonyl of residue (i) and amide nitrogen of residue (i + 2) to show the dependency of REDOR echo intensity on the peptide tilt angle relative to the membrane normal. The approach was applied to the labeled transmembrane domain of phospholamban ([(15)N-Leu(37), (13)C-Leu(39)]PLBTM) incorporated into dimyristoylphosphatidylcholine bilayers. The dephasing observed for a random membrane dispersion showed that the peptide was alpha-helical in the region including the two labels, and dephasing in oriented membranes showed that the peptide helix was tilted by 25 degrees +/- 7 degrees relative to the bilayer normal. These results agree with those obtained by other spectroscopic methods.

A solid-state NMR study of the phospholamban transmembrane domain: local structure and interactions with Ca(2+)-ATPase

The structure and dynamics of a double (13)C-labelled 24-residue synthetic peptide ([(13)C(2)]CAPLB(29-52)), corresponding to the membrane-spanning sequence of phospholamban (PLB), were examined using (13)C cross-polarisation magic-angle spinning (CP-MAS) NMR spectroscopy. CP-MAS spectra of [(13)C(2)]CAPLB(29-52) reconstituted into unsaturated lipid membranes indicated that the peptide was mobile at temperatures down to -50 degrees C. The NMR spectra showed that peptide motion became constrained in the presence of the SERCA1 isoform of Ca(2+)-ATPase, and chemical cross-linking experiments indicated that [(13)C(2)]CAPLB(29-52) and Ca(2+)-ATPase came into close contact with one another. These results together suggested that the peptide and the 110-kDa calcium pump were interacting in the membrane. Rotational resonance CP-MAS (13)C-(13)C distance measurements on [(13)C(2)]CAPLB(29-52) reconstituted into lipid bilayers confirmed that the sequence spanning Phe-32 and Ala-36 was alpha-helical, and that this structure was not disrupted by interaction with Ca(2+)-ATPase. These results support the finding that the transmembrane domain of PLB is partially responsible for regulation of Ca(2+) transport through interactions with cardiac muscle Ca(2+)-ATPase in the lipid bilayer, and also demonstrate the feasibility of performing structural measurements on PLB peptides when bound to their physiological target.

Effectiveness of health education in promoting the use of iodized salt in Lotkoh, tehsil Chitral, Pakistan

INTRODUCTION

We evaluated the effect of health education on the use of iodized salt in a remote region.

METHODS

We randomly selected 31 villages in teh Lotkoh tehsil of district Chitral in the North West Frontier Province of Pakistan. We then randomly selected 7 households from each village and inteviewed the eldest women of the family. We also tested samples of salt for iodine concentration at the user's level.

RESULTS

Eighty-five percent of families (184/217) used iodized salt exclusively. Among the samples population, the Aga Khan Health Services (AKHS) informed 67% about the importance of iodized salt. Shopkeepers and neighbors informed 25%. People informed by AKHS were more likely to know the volatile nature of iodine (76% vs 55%, p < 0.001) and the advantages of iodized salt (91% vs. 75%, p = 0.001) than persons informed by other sources. People who could name any single advantage of iodized salt were more likely to use iodized salt (97%) compared to those who could not name any advantages (62%) (p < 0.001) Iodine concentration in 78% (141/183) samples was acceptable (> or = 15 ppm). One specific brand of salt consistently had sufficient iodine concentration (91%) compared to all others (47%) (p < 0.001).

CONCLUSION

Health education has been effective in promoting the use of iodized salt in these isolated rural communities. A joint effort by the government, local NGOs and the community can substitute the role of mass media in such areas. Regular evaluation of iodized salt brands should be considered.

Percutaneous cuffed catheter insertion by nephrologists

The use of Dacron cuff double-lumen permanent catheters for hemodialysis has become more common in the dialysis unit as patients await for creation or maturation of a permanent hemoaccess for various reasons. Placement of these catheters is often done by surgeons. Nephrologists skilled in the placement of temporary central vein accesses can extend their skill to placement of cuff catheters with the current available peel-away insertion technique. Data are presented on the percutaneous placement of 77 Dacron cuff permanent catheters by 4 nephrologists in two medical centers in a nonoperating room setting with minimal complications.

Tc-99m erythrocyte localization of an intramuscular hemangioma of the arm

An unusual case of intramuscular hemangioma of the left triceps muscle is presented. This tumor may infiltrate the muscle and be misdiagnosed as a malignant neoplasm.

Social deprivation and prevalence of epilepsy and associated health usage

OBJECTIVES

To examine the relation between social deprivation and the prevalence of epilepsy and associated morbidity using hospital activity data as a proxy.

METHODS

The study was conducted in the health district of South Glamorgan, United Kingdom (population 434 000). Routinely available hospital data (inpatient and outpatient), an epilepsy clinic database, and mortality data underwent a process of record linkage to identify records relating to the same patient and to identify patients with epilepsy. Each patient was allocated a Townsend index deprivation score on the basis of their ward of residence. Age standardised correlations were calculated between deprivation score and prevalence of epilepsy, inpatient admissions, and outpatient appointments. Standardised mortality ratios (SMR) were also calculated. All analyses were performed on two cohorts: (1) all patients with epilepsy and (2) those patients with epilepsy without any underlying psychiatric illness or learning disability.

RESULTS

The prevalence of epilepsy ranged between 2.0 and 13.4 per 1000 with a median of 6.7. There were positive correlations between social deprivation and prevalence in both populations: (1) r=0.75 (p<0.001) and (2) r=0.70 (p<0.001). After standardising for underlying prevalence there were also correlations for mean inpatient admissions: (1) r=0.62 (p<0.001), (2) r=0.59, (p<0.001) and for outpatient appointments: (1) r=0.53, (p=0.001) and (2) r=0. 51 (p=0.001). The SMR for those deprived was (1) 1.66 (95% confidence interval (95% CI) 1.27-2.05) and (2) 1.80 (95% CI 0.71-1. 67). For the population as a whole (with and without epilepsy) the SMR was 1.25 (95% CI 1.27-2.32).

CONCLUSION

This study shows a strong correlation between the prevalence of epilepsy and social deprivation and weaker correlations between social deprivation and mean hospital activity.

Adhesion, alignment, and migration of cultured Schwann cells on ultrathin fibronectin fibres

Individual fibres of fibronectin (Fn-fibres), an extracellular matrix cell adhesion glycoprotein, were produced from a purified solution of fibronectin. These fibres range from 0.5-7 microm in width and have been engineered to produce mats (Fn-mats) by using a unidirectional shear force to orientate the fibres. Fn-fibres have been shown to promote alignment by contact guidance of human dermal fibroblasts, neurites, macrophages, and epitenon fibroblasts. Fn-mats have been used to orientate and enhance the regeneration of peripheral nerve components. We investigated cell spreading, orientation, formation of focal contacts, and the speed of cell movement on individual Fn-fibres, glass-covered with poly-L-lysine and poly-L-lysine/laminin/Fn. Fibronectin fibres significantly promoted cell spreading and the speed of cell migration with alignment of focal contacts and F-actin filaments to the axis of the fibres. The study reveals the potential of Fn-fibres to guide and direct cellular behaviour by contact guidance. The increase in migration and other behaviour exhibited by Schwann cells on Fn-fibres justifies the use of Fn-mats for peripheral nerve repair and is clinically important in that atrophy of the target organ, which is the most common failure of nerve repair, may be minimised.

The APS adapter protein couples the insulin receptor to the phosphorylation of c-Cbl and facilitates ligand-stimulated ubiquitination of the insulin receptor

The APS adapter protein is rapidly tyrosine-phosphorylated following insulin stimulation. In insulin-stimulated 3T3-L1 adipocytes, APS co-precipitated with phosphorylated c-Cbl. In CHO.T-APS cells overexpressing the insulin receptor and APS, APS co-precipitated with c-Cbl but not in CHO.T cells which do not express APS. APS-mediated recruitment of c-Cbl to the insulin receptor led to rapid ubiquitination of the insulin receptor beta-subunit in CHO. T-APS but not in parental CHO.T cells. These results suggest that the function of APS is to facilitate coupling of the insulin receptor to c-Cbl in order to catalyse the ubiquitination of the receptor and initiation of internalisation or degradation.

Low concentrations of fibrinogen increase cell migration speed on fibronectin/fibrinogen composite cables

Optimal cell migration rate in a given direction (velocity) is a function of speed and directional persistence. Migration speed has been reported to be a function of adhesion strength such that optimal cell migration occurs where the cell is able to form enough stable attachments for good traction while allowing attachments at the trailing end to be broken during locomotion. This is particularly important in peripheral nerve regeneration where rapid Schwann cell recruitment across the injury site will lead to better functional recovery and reduced end organ atrophy. The aim here was to investigate the effects of changing adhesion properties of Fn materials by adding fibrinogen in order to design an optimal material for repair processes. Cell migration on Fn/Fg-cables increased with increasing content of %Fg to a peak cell migration velocity (Schwann cells) of 49 microm/h, at 50% Fg. Further increases in Fg content hindered cell migration. Vinculin-rich attachment plaques were reduced in a dose-dependent manner as the content of %Fg was increased whilst cells at the optimum Fg proportion for cell migration were moderately well spread. These results support the idea that optimum cell migration rates occur at intermediate attachment conditions, in this case at 50% Fg. These results show that incorporation of Fg into Fn-based materials will enhance the speed of Schwann cell migration and this would be likely to improve peripheral nerve regeneration. Indeed, directionally aligned Fn-based materials can now be engineered to give optimal cell velocity during repair cell recruitment in a range of tissue repair or tissue engineering applications.

Trends in initiation of dialysis in an urban dialysis clinic in the United States: a long way from dialysis outcomes quality initiative guidelines

The guidelines issued for peritoneal dialysis by the National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) suggest initiation of dialysis at a glomerular filtration rate (GFR) of 10.5 mL/min/1.73 m2. We undertook this study to determine trends at a center in Philadelphia. Using the MDRD (Modification of Diet in Renal Disease) formula, we estimated the GFR (mL/min/1.73 m2) at the time of first dialysis for patients starting on dialysis at the center between 1994 and 1996. Data on 72 of the 86 new patients were available. Of the 72, 69 patients (96%) were black and 29 (40%) were diabetic. The estimated GFR at the time of dialysis initiation was 6.3 +/- 0.3 mL/min/1.73 m2. Only 3 patients (4%) had a GFR > 10.5; 25 patients (35%) had GFR < 5.0. Patients with a lower GFR had more severe acidosis (HCO3 15.8 +/- 0.5 mmol/L vs 19.5 +/- 0.9 mmol/L, p = 0.0023) and greater impairment in divalent ion metabolism (PO4: 7.6 +/- 0.2 mg/dL vs 5.6 +/- 0.3 mg/dL, p < 0.0001). Diabetic patients were initiated on dialysis at a higher level of GFR than non diabetic patients (7.2 +/- 0.3 mL/min/1.73 m2 vs 5.7 +/- 0.4 mL/min/1.73 m2, p = 0.0087). Even though diabetic patients had higher GFR and lower serum creatinine (8.6 +/- 0.5 mg/dL vs 11.8 +/- 0.9 mg/dL, p = 0.0021) than non diabetic patients, blood urea nitrogen (BUN) was similar in the two groups (89 +/- 3.7 mg/dL vs 96.8 +/- 5.8 mg/dL, p = 0.73). This difference may indicate that nondiabetic patients had a greater decline in protein intake. Finally, a trend towards initiation of dialysis at higher levels of renal function was seen with time (GFRs 5.5 +/- 0.4 mL/min/1.73 m2, 6.4 +/- 0.4 mL/min/1.73 m2, and 6.9 +/- 0.6 mL/min/1.73 m2 for 1994, 1995, and 1996 respectively; p = 0.058, 1994 vs 1996). The trend was stronger for diabetic patients (GFR 6.3 +/- 0.4 mL/min/1.73 m2 and 8.1 +/- 0.7 mL/min/1.73 m2 for 1994 and 1996 respectively; p = 0.06) than for non diabetic patients (GFR 5.1 +/- 0.5 mL/min/1.73 m2 and 6.2 +/- 0.7 mL/min/1.73 m2 for 1994 and 1996 respectively; p = 0.22). We conclude that initiation of dialysis is delayed in urban centers, particularly in non diabetic patients, and that the current practice is far below the DOQI recommendations.

Health care provision for people with a learning disability. Record-linkage study of epidemiology and factors contributing to hospital care uptake

BACKGROUND

We know little about how people with a learning disability access secondary health care.

AIMS

To describe the epidemiology of learning disability, the influence of deprivation on prevalence and the pattern of secondary care uptake, including the effect of institutionalisation.

METHOD

A record-linkage study of secondary care contacts of 434,000 people between 1991 and 1997. A population with learning disability was identified; their secondary care contact was calculated and compared with the general population's.

RESULTS

The distribution of people with a learning disability (n = 1595) correlated significantly with deprivation. The presence of a learning disability hospital significantly affected care uptake. Place of residence also affected acute admission to the learning disability hospital. Former institution residents generated 212 admissions per 1000 patients; community patients generated 18 per 1000. The admission rate with any psychiatric diagnosis to any setting was 26.3 per 1000 people with a learning disability; 16.5% of such patients had a dual diagnosis.

CONCLUSIONS

Health provision for people with a learning disability is affected by institutional provision.

Activation of platelet-activating factor (PAF) receptor stimulates nitric oxide (NO) release via protein kinase C-alpha in HEC-1B human endometrial epithelial cell line

BACKGROUND

Impairment of the fertility in the platelet-activating factor (PAF) receptor transgenic female mice suggests changes in PAF functions can influence uterine receptivity. We hypothesized that vasodilatory actions of PAF in the uterus was exerted by PAF-mediated nitric oxide (NO) release via activation of isoenzyme-specific protein kinase C (PKC).

MATERIALS AND METHODS

Inducible and endothelial NOS was shown by Reverse transcription polymerase chain reaction RT-PCR in cDNA synthesized from RNA extract of proliferative and secretory endometrium as well endometrial epithelial cell lines HEC-1B. The effect of WEB2170, N(G)-monomethyl-L-arginine (L-NMMA) and Ro31-8220 on PAF mediated NO release by HEC-1B cell was determined. PAF induced translocation of PKCalpha in HEC-1B cell and its antagonist effect by Ro 31-8220 was studied by Western immunoblot analysis. PKC isoenzyme regulated by PAF was determined in HEC-1B cell lysate by immunoprecipitation.

RESULTS

PAF-evoked a rapid and concentration-dependent biphasic increase in total NO in human HEC-1B endometrial epithelial cell line [as measured by a Sievers NOA 280A NO Chemiluminescent Analyser.] This increase in NO release was attenuated by the PAF receptor antagonist, WEB2170. Inhibition of NO synthesis by N(G)-monomethyl-L-arginine produced marked dose-dependent attenuation of PAF-mediated NO release, indicating nitric oxide synthase (NOS) activation. PAF-mediated NO release was also inhibited by the PKC inhibitor Ro 31-8220 and by the removal of extracellular calcium, suggesting a dependency on PKC and calcium, respectively. RT-PCR analysis showed expression of inducible NOS and endothelial NOS in human endometrium, myometrium and HEC-1B cells. Western immunoblot analysis showed PKCalpha, betaII and iota were the principal isozymes present in the HEC-1B cell line and normal endometrium, suggesting that both HEC-1B cells and normal endometrium have similar PKC isozymes. PAF induced the translocation of both PKCalpha and PKCiota within the time frame of NO release. The translocation of PKCalpha, but not PKCiota, was susceptible to inhibition by Ro 31-8220 that also inhibited PAF-evoked NO release, suggesting that PKCalpha is the principal isozyme involved in this process and that eNOS may be a substrate for PKCalpha. Kinase assays performed using immunoprecipitated PKCalpha showed that PAF (1 nM) activated PKCalpha that was inhibited by co-incubation with Ro31-8220 and Ca(2+)-free medium.

CONCLUSIONS

This study demonstrates that PAF-stimulated NO release via PKCalpha in epithelial cells might regulate endometrial functions such as implantation and menstruation.

Reducing antipsychotic medication in people with a learning disability

BACKGROUND

The use of antipsychotic drugs in people with learning disabilities is currently receiving intensified scrutiny and attempts are being made to reduce it.

AIMS

A randomised controlled trial was designed to investigate factors influencing antipsychotic drug reduction among people with learning disabilities prescribed such medication for behavioural problems.

METHOD

Thirty-six participants randomly allocated to the experimental group underwent four, monthly 25% drug reduction stages. There were no planned drug changes for the control group (n = 20).

RESULTS

Twelve participants (33%) completed full withdrawal; a further seven (19%) achieved and maintained at least a 50% reduction. Drug reduction was associated with increased dyskinesia and higher activity engagement but not increased maladaptive behaviour. Some setting characteristics were associated with drug reinstatement.

CONCLUSIONS

A substantial proportion of people with learning disability prescribed antipsychotic medications for behavioural purposes rather than for treating psychotic illness can have their drugs reduced or withdrawn.

Nerve growth factor enhances peripheral nerve regeneration in non-human primates

Fibronectin mat implants impregnated with NGF have been successfully used in rat nerve regeneration model. The aim of this study was to assess their action in a primate model. Mats were implanted into a 5 mm gap in a peripheral nerve in Macaca fascicularis monkeys, either alone (Fn) or in the presence of nerve growth factor (Fn + NGF). Four months postoperatively, the regenerated nerve was analysed by light microscopy, and target skin reinnervation was assessed by quantification of cutaneous nerve terminals immunostained with protein gene product (PGP) antibodies. The diameter of the regenerated nerve was similar in Fn + NGF grafts and nerve autografts, but significantly larger for plain Fn grafts with evidence of more connective tissue surrounding the axons. Myelinated fibres counts showed similarities in normal control nerve, nerve autograft and Fn + NGF graft groups. However, in nerve grafted with plain Fn mats the regenerating fibres were lower in number and showed a wider variability in diameter and myelination, resulting in a significantly smaller G-ratio (axonal diameter/myelinated fibre diameter). The amount of cutaneous reinnervation was lowest in Fn graft group, while comparable amounts of skin reinnervation were observed in the Fn + NGF and autograft groups. These results suggest that Fn-mats are a suitable conduit to promote peripheral nerve regeneration also in primate, and supplying NGF locally at the lesion site can further enhance nerve regrowth.

APS, an adapter protein with a PH and SH2 domain, is a substrate for the insulin receptor kinase

APS (adapter protein with a PH and SH2 domain) is the newest member of a family of tyrosine kinase adapter proteins including SH2-B and Lnk. We previously identified SH2-B as an insulin-receptor-binding protein and substrate [Kotani, Wilden and Pillay (1998) Biochem J. 335, 103-109]. Here we show that APS interacts with the insulin receptor kinase activation loop through its SH2 domain and insulin stimulates the tyrosine-phosphorylation of APS. Furthermore, the phosphorylation of activation-loop tyrosine residues 1158 and 1162 are required for this interaction.

PGE(2)-mediated inhibition of T cell p59(fyn) is independent of cAMP

We recently observed that prostaglandin E(2) (PGE(2))-mediated suppression of T cell functions could result from an attenuation of p59(fyn) protein tyrosine kinase activity. The present study evaluated the effects of an adenylate cyclase agonist (forskolin) and antagonist (SQ-22536), as well as those of cAMP analogues (dibutyryl cAMP and 8-bromo- cAMP), on T cell p59(fyn) kinase activity. The study allowed us to assess whether PGE(2)-mediated activation of adenylate cyclase by itself or the elevation in intracellular cAMP levels is an integral event in the modulation of anti-CD3-linked p59(fyn) activation in T cells. The experiments were carried out with splenic T cells from male Sprague-Dawley rats. A 30-50% suppression in the autophosphorylation and the kinase activity of p59(fyn) in T cells incubated with PGE(2) or forskolin was observed. Pretreatment of T cells with SQ-22536 prevented significant PGE(2)-mediated inhibition of T cell p59(fyn) kinase activity. In contrast, no change in p59(fyn) autophosphorylation and kinase activity in T cells treated with cAMP analogues was observed. These data suggest that PGE(2)-mediated suppression of p59(fyn) autophosphorylation and kinase activity in T cells is dependent on the activation of adenylate cyclase and independent of the elevation in cAMP levels.

Prostaglandin E2 down-regulation of T cell IL-2 production is independent of IL-10 during gram-negative sepsis

The present study ascertained the role of PGE2 in sepsis associated modulation of IL-2 and IL-10 production by T cells. Sepsis was induced in 225-250 g male rats (Sprague Dawley) by implanting fecal pellets containing Escherichia coli (100-150 CFU) and Bacteroides fragilis (10(4) CFU) into the abdominal cavity. Animals implanted with fecal pellets without the bacteria were designated as sterile. For the assessment of PGE2 role in sepsis, a group of septic and sterile rats were pretreated with indomethacin to inhibit endogenous PGE2 synthesis. Splenic T cells were obtained 48 h after septic or sterile implantations, and their IL-2 and IL-10 production was measured. A significant suppression in the levels of IL-2 production and mRNA expression was observed in T cells from septic rats compared with the T cells from sterile and control rats. IL-10 protein and mRNA expression was found to be significantly higher in septic rat T cell compared to sterile and control rat T cells. Although, treatment of animals with indomethacin significantly prevented the sepsis-related suppression of IL-2 production, such treatment of animals was associated with a further upregulation of IL-10 production. These data suggest that although PGE2 released during sepsis can cause T cell IL-2 down-regulation, it may not mediate the T cell IL-10 upregulation. The IL-2 down-regulation may not be an effect of IL-10 upregulation.

Stabilization of fibronectin mats with micromolar concentrations of copper

Fibronectin, a large extracellular matrix cell adhesion glycoprotein has diverse functions in wound repair including organization of matrix deposition and promotion of angiogenesis. We have previously shown that purified plasma fibronectin can be made into three-dimensional, fibrous materials, termed fibronectin mats (Fn-mat). The aim of this study was to examine means of increasing the stability of Fn-mats using a novel treatment with micromolar concentrations of copper ions which may be used to improve wound healing/nerve repair. Cytotoxicity of incorporated copper was determined using rat Schwann cells, rat tendon fibroblasts and human dermal fibroblasts. Dissolution of protein from the Fn-mat showed that treatment with the lowest concentration of copper used (1 microM) increased the stability of mats by 3-4 times at room temperature relative to control mats and twofold at 37 degrees C. Copper mediated increase in stability was dose dependent. Orientation of the Fn-fibres (within mats), monitored by scanning electron microscopy was retained with 1 microM copper but disappeared with higher concentrations. Schwann cells grew in culture with mats stabilized by 1 microM copper treatment without reduction in cell number but growth was inhibited at 10-200 microM Cu. All types of fibroblasts were unaffected by copper treatment upto 200 microM. Fn-mats can be successfully stabilized by this technique producing longer survival in vitro. The differential effects of copper on these cell types suggests that CuFn-mats may be used to select the type of cells which colonize these materials.

Production of d-lyxose from d-glucose by microbial and enzymatic reactions

D-arabitol was first prepared from D-glucose using Candida famata R28. The reaction gave 5.0% D-arabitol from 10.0% D-glucose. D-arabitol was then almost completely converted to D-xylulose using Acetobacter aceti IFO 3281. Finally, D-lyxose was prepared from D-xylulose enzymatically using L-ribose isomerase from toluene-treated cells of Acinetobacter sp. strain DL-28. The isomerization reaction progressed steadily and the concentration of D-xylulose increased from 1.0 to 10.0%. About 70% of D-xylulose was converted to D-lyxose in all cases. Separation of residual D-xylulose from the reaction mixture is very difficult to achieve by column chromatography, but D-xylulose could be selectively degraded easily using Saccharomyces cerevisiae IFO 0841. The product was crystallized and was confirmed to be D-lyxose by HPLC, 13C-NMR spectra, IR spectra analysis, and optical rotation measurement.

Complications associated with different insertion techniques for Hickman catheters

A dependable central venous access is an essential prerequisite for the delivery of care to the cancer patients. This has become easier since the introduction of indwelling central venous catheters. However, pancytopenia, often encountered in haematological malignancies, does influence the morbidity associated with these catheters. In this study the effects of two different placement techniques of Hickman catheters were evaluated. A total of 177 Hickman catheters were inserted in patients suffering from haematological malignancies. In 112 patients the catheters were placed percutaneously into subclavian veins without prior tunnelling; in the other 65 patients these were introduced, after having been tunnelled, into cephalic/external jugular veins by a cut-down technique. The catheters remained in use in each patient for between 18 and 253 days. Excessive bleeding and haematoma formation occurred in a significantly higher proportion of patients from the cut-down group (61% and 41%, respectively) compared to patients from the percutaneous group (8% and 0%, respectively). These in turn had a profound impact on the incidence of infective complications. Catheter exit site infection, tunnel infection and septicaemia were observed in 26%, 18%, and 41%, respectively, of the patients from the cut-down group, while in patients from the percutaneous group, skin exit site infection was noted only in 7% and septicaemia in 19% of patients. It was concluded that the placement technique of these catheters exerts a significant influence on the immediate as well as delayed complications. The results indicate that the insertion technique requiring minimal dissection is more beneficial. It is therefore recommended that percutaneous insertion without tunnelling should be the technique of choice for catheter placement.

Cough, chest pain and rash

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Learning disabilities: moving forward--a focus on epilepsy, Birmingham, England, 29 June 1996

On 29 June 1996 a conference was held in Birmingham to highlight the status of epilepsy in people with learning disabilities. The conference consisted both of seminars and workshops. Dr Tim Betts, Birmingham; Dr Greg O'Brien, Northumberland; and Dr Mike Kerr addressed issues of assessment, diagnosis and drug treatment of epilepsy in this population. This meeting report summarizes the proceedings of the conference.

Complete gastric outlet obstruction following acid ingestion complicated by acute pancreatitis and disseminated intravascular coagulation

A case is described where accidental acid ingestion resulted in the development of oesophageal stricture and complete gastric outlet obstruction. Following a smoothly conducted pre-surgery endoscopic examination the patient developed acute pancreatitis, which, on initial clinical examination, was diagnosed as a viscus perforation. The severity of pancreatitis was such as to lead to disseminated intravascular coagulopathy and ultimately death. The interest lies in the fact that pancreatitis was precipitated in a previously traumatised stomach by such an innocuous procedure as fibre-optic endoscopy.

Cartilage calcification and limb bud growth in the developing tich mouse embryo

The tich mutation leads to the abnormal development of bones in mice such that a 'V-shaped' tongue of noncalcified cartilage appears in the central portion of the proximal tibial growth plate. In this study, alcian green staining of cartilage glycosaminoglycans was used to demonstrate the pattern of limb development in embryos of stage-matched tich and normal, co-isogenic, A.TL mice from the earliest stages in skeletogenesis. The growth plates of normal A.TL siblings were symmetrical across the limb rudiment whereas the growth plate in tich siblings show the beginnings of a V-shaped tongue of cartilage reaching towards the diaphysis. This showed first at E16.5. It was apparent that the crown rump distance, tibia, ulna, and the length of calcified cartilage in tich were significantly shorter than A.TL. These results confirmed that calcification was not the primary defect in tich but point to a temporal dysfunction in growth factor expression (possibly bone morphogenetic proteins) that stems from early limb bud formation and translates through later stages in development.

Drug-induced nephrotoxicity

Drug-induced renal dysfunction is not an uncommon event, which can cause significant morbidity and can be easily overlooked. Many medications can lead to renal dysfunction through various mechanisms. The most common medications or classes of medications along with their clinical presentations are discussed in this article. As can be noted, many drugs can cause nephropathy in more than one way. Because it is difficult to discuss nephrotoxicities of every reported medication, Tables 1, 2, and 3 are provided; although these tables are by no means comprehensive, they may serve as further reference. This article is intended to provide a broad overview of the spectrum of presentation associated with drug-induced nephrotoxicity to guide the clinician to familiarity with this entity.

Asymptomatic urinary abnormalities. Hematuria and proteinuria

Asymptomatic urinary abnormalities including hematuria and proteinuria are commonly detected in routine urinalysis. They may be of benign etiology or indicative of more serious underlying disease. This article is intended to give clinicians a guide for evaluation of hematuria and proteinuria.

Graft surveillance and angioplasty prolongs dialysis graft patency

BACKGROUND

In the United States of America, vascular access complications are the most frequent cause of death among patients with end-stage renal disease on hemodialysis. The majority of American patients with end-stage renal disease have prosthetic grafts for access. The most common complication of prosthetic graft fistulas is thrombosis. To prolong graft life and decrease the frequency of operations, a university-based dialysis unit adopted a policy of graft surveillance by measuring venous resistance, followed by fistulagram and percutaneous dilatation of identified stenoses. The purpose of this retrospective study is to determine if this policy affected graft patency and graft life.

STUDY DESIGN

This retrospective review compares outcomes for two years before adoption of this policy (control group, 210 patients) with the outcomes for three years after adoption (study group, 260 patients). Fifty (24 percent) of the control group and 71 (27 percent) of the study group were defined as "complicated" patients because they underwent more than one intervention over any 12-month period.

RESULTS

The 50 complicated patients in the control group underwent 104 operations for thrombosis over two years, 1.04 thrombotic episodes and operations per patient year. Seventy new grafts were placed with a mean primary patency of 3.9 months. Mean graft survival time was 6.3 months. The 71 complicated patients in the study group underwent 111 fistulagrams, 80 angioplasties, and 110 operations over three years, for 0.52 thrombotic episodes per patient year (p < .001). Forty-five new grafts were placed with a primary patency of 11.5 months (p < .001). Mean graft survival time was 15.8 months (p < .001).

CONCLUSIONS

This retrospective study demonstrates the effectiveness of a policy of graft surveillance and percutaneous treatment of graft stenosis in prolonging primary surgical patency and graft survival.

Acute renal failure of obstetrical origin during 1994 at one center

Although preventable, acute renal failure (ARF) of obstetrical origin continues to be common in developing countries. During the year 1994, we treated a total of 238 cases of ARE. Of these cases, 43 (18%) were of obstetrical origin. All of the patients were known to be previously healthy. Acute renal failure occurred in association with antepartum hemorrhage in 15, postpartum hemorrhage in 10, intrauterine death of fetus in 11, preeclampsia or eclampsia in 9, and septic abortions or puerperal sepsis in 7. Thirty-six patients required dialysis therapy because of moderate to severe azotemia. Renal histology was studied in 12 cases. Acute cortical necrosis was present in 9, extensive tubular necrosis in 2, and 1 patient had membranoproliferative glomerulonephritis. Twenty-two (51%) patients recovered normal renal function, while 11 (26%) developed irreversible renal dysfunction and 10 (23%) expired. Mortality and morbidity in this region is still quite high in obstetrical situations. Poor health infrastructure and lack of antenatal health clinics leads to development of major complications at the time of childbirth, which is mostly conducted at home by untrained personnel in quite a few cities of the country.

Deep vein thrombosis as a predictor of cancer

An association between cancer and venous thrombosis has long been recognized. In an attempt to find whether venous thrombosis can serve as a reliable predictor of subsequent cancer, 196 cases of confirmed venous thrombosis treated over a seven-year period were reviewed. Of a total of 196 cases, 113 were found to suffer from primary type deep venous thrombosis (DVT), whereas 83 were allocated to secondary type DVT. Of 113 cases with primary DVT, 23 had suffered from recurrent episodes, whereas 90 had only a single episode. From the secondary DVT group of 83 patients, 14 suffered from recurrent episodes and 69 had a single episode. Of the patients in the primary DVT group, 2.65% (3/113) developed cancer subsequently, whereas none was detected among the group of 83 patients who had secondary DVT. In the group of 113 patients with primary DVT, the incidence was higher among those who had recurrent episodes (4.34%, 1/23) than among those who had a single episode (2.22%, 2/90). The overall incidence of cancer among 196 cases of DVT was found to be 1.53% (3/196). The findings do not support the routine screening of all DVT patients by expensive diagnostic modalities. These patients should rather be assessed by careful clinical examinations and baseline investigations. The detailed investigations should be resorted to if there is any suggestion of presence of occult malignancy by these simpler means. One should be more vigilant in case of patients suffering from primary type DVT, for the incidence in this group is significantly higher.

Management of flail chest injury: internal fixation versus endotracheal intubation and ventilation

A total of 427 patients with major chest trauma were treated in two major hospitals in Abu Dhabi, United Arab Emirates, during a 10-year period. In 64 of 426 patients, flail chest injury was the dominant factor among other injuries that were insignificant. Among 64 cases of flail chest injury, 25 were managed by internal fixation of ribs, whereas the remaining 38 were managed by endotracheal intubation and intermittent positive-pressure ventilation alone. Of the patients treated by internal fixation 80% (21/26) were weaned from the ventilator within an average of 1.3 days, whereas the remaining 20% (5/26) continued to need assisted ventilation for a longer duration; the total average duration of assisted ventilation for the whole group was 3.9 days. In comparison, among 38 patients with flail chest injury treated by endotracheal intubation and ventilation alone, the average duration of assisted ventilation was 15 days. In the group treated by internal fixation 11% (3/26) of the patients ultimately required a tracheotomy, whereas in the patients treated by intubation and ventilation alone tracheostomy was required in 37% (14/38) of the cases. In the group treated by internal fixation, chest infection was documented in 15% (4/26), septicemia in 4% (1/26), and barotrauma in 0%; in the other group these complications occurred in 50% (19/38), 24% (9/38), and 8% (3/38) of the cases, respectively. The mortality rate was 8% (2/26) in the surgically treated patients, whereas it was 29% (11/38) in the other group. All the deaths in both groups were ascribed to adult respiratory distress syndrome. Average stay in the intensive care unit was 9 days for the patients treated by internal fixation, whereas it was 21 days in the group treated by intubation and ventilation alone. The treatment of flail chest injury in our series by internal fixation resulted in speedy recovery, decreased complications, and better ultimate cosmetic and functional results and proved to be cost effective.

Cell proliferation within the growth plate of the tich mouse

The pattern of chondrocyte proliferation was studied in the proximal tibial growth plate of tich mice (gene symbol tch), a recessive mouse mutant, which is coisogenic with the A.TL strain. Specimens were qualitatively studied at time points of 2, 3, 4, 6, and 8 weeks of age by bromodeoxyuridine labeling of cell division and routine histology. At 2 weeks, when the lesion appeared as a full-width thickening of the growth plate, a greater proportion of cells appeared positively labeled in the proliferative zone. This concavity in the central portion of the growth plate became progressively more focal between 3 and 4 weeks to give a "tongue" of unresorbed, noncalcified cartilage in the central region of the tich growth plate. BrdUrd labeling indicated that the appearance of the cartilage tongue corresponded with increased cell division in the central region of the growth plate. At the same time, a "second" zone of cell division formed, within the zone of hypertrophy, such that labeled cells appeared to be set among chondrocytes with hypertrophic morphology. At stages after 4 weeks of age the focal feature disappeared as the growth plate returned to more normal morphology by maturity. It seems that this unique "second" zone of dividing cells may contribute to formation of an elongation of the nonresorbed tongue of cartilage. However, it is not likely to be the primary defect since growth plate changes were apparent at earlier stages.

Correlation of venography, venous pressure, and hemoaccess function

We analyzed the anatomic features of both grafts and fistulas and correlated these features with access function. We also attempted to determine venous pressures predicting access dysfunction (critical venous pressures) at various blood flow rates (BFRs). Therefore, accesses of 46 chronic hemodialysis patients were studied by venography in a prospective fashion. We defined the incidences of various lesions and the effects of venous collaterals on graft function, and determined critical venous pressures at various BFRs. Eighty-three percent of the accesses had outflow obstruction. Five types of anatomic lesions were identified. The incidences were venous stenosis of the draining vein immediately proximal to the venous anastomosis, 36.4%; central vein, 23.6%; venous anastomosis, 25.5%; arterial anastomosis, 10.9%; and intragraft hyperplasia, 3.6%. Twelve patients had multiple lesions. When the homogenous polytetrafluoroethylene arm graft population was studied for the effect of venous collaterals, we found that venous collaterals conferred protection but did not prevent graft failure. Venous pressure measurements were good predictors of access failure at the lower BFRs. Venous pressures increased with increasing BFRs. A critical venous pressure of 145 mm Hg was found for a BFR of 250 mL/min. At a BFR of 300 mL/min, the critical venous pressure was 170 mm Hg. A critical venous pressure could not be found for a BFR of 400 mL/min.