Acyclic pyrazolo[3,4-d]pyrimidine nucleoside as potential leishmaniostatic agent

A new synthesis of 6-amino-1-hydroxyethoxymethyl-4 (5H)-oxopyrazolo[3, 4-d]pyrimidine (4) has been mentioned. Compound 4 exhibited inhibition of amastigotes of Leishmania donovani to the extent of 89 % at 30 microg/mL, whereas iso-guanine analogue 5 had the inhibition only to the extent of 52.8% at 100 microg/mL in vitro. In hamster model the maximum inhibitory response for compound 4 against amastigotes multiplication was observed to be 94% at 50 mg/kg single dose for 5 consecutive days.

The immune responses to human and microbial heat shock proteins in periodontal disease with and without coronary heart disease

The human 60 kDa and microbial 65 kDa heat shock proteins (HSP) have been implicated in the pathogenesis of chronic periodontitis (P) and coronary heart disease (CHD). We have studied four male non-smoking cohorts of 81 subjects, matched for age. Group (a) consisted of a healthy group with minimal gingivitis (n = 18), group (b) were patients with P (n = 23), group (c) patients with CHD and minimal gingivitis (n = 20) and group (d) patients with CHD and P (n = 20). T cells separated from peripheral blood were found to be primed to both microbial HSP65 and human HSP60 but significant CD4, human leucocyte antigen (HLA) class II-restricted proliferative responses were found only with the human HSP60 in patients with P (P < 0.001) and CHD without (P < 0.001) or with (P < 0.00001) periodontitis. Dose-dependent inhibition of T cell proliferative responses was carried out to determine the receptors involved in recognition of HSP60 and HSP65. Monoclonal antibodies to CD14 showed inhibition of T cell proliferation stimulated by both HSP60 and HSP65, consistent with the role of CD14 as a receptor for these HSPs in P and CHD. The toll-like receptor 2 (TLR-) and TLR-4 were then studied and these showed that TLR-4 was recognized by microbial HSP65, whereas TLR-2 was recognised by human HSP60 in both P and CHD. However, a dissociation was found in the HSP60 and TLR4 interaction, as TLR4 appeared to have been recognized by HSP60 in P but not in CHD. The results suggest an autoimmune or cross-reactive CD4(+) class II-restricted T cell response to the human HSP60 in P and CHD. Further studies are required to determine if there is a common epitope within HSP60 that stimulates T cell proliferation in P and CHD.

Cross-reactivity of GroEL antibodies with human heat shock protein 60 and quantification of pathogens in atherosclerosis

BACKGROUND/AIMS

Chronic infections such as those caused by Chlamydia pneumoniae and periodontopathic bacteria such as Porphyromonas gingivalis have been associated with atherosclerosis, possibly due to cross-reactivity of the immune response to bacterial GroEL with human heat shock protein (hHSP) 60.

METHODS

We examined the cross-reactivity of anti-GroEL and anti-P. gingivalis antibodies with hHSP60 in atherosclerosis patients and quantified a panel of six pathogens in atheromas.

RESULTS

After absorption of plasma samples with hHSP60, there were variable reductions in the levels of anti-GroEL and anti-P. gingivalis antibodies, suggesting that these antibodies cross-reacted with hHSP60. All of the artery specimens were positive for P. gingivalis. Fusobacterium nucleatum, Tannerella forsythia, C. pneumoniae, Helicobacter pylori, and Haemophilus influenzae were found in 84%, 48%, 28%, 4%, and 4% of arteries, respectively. The prevalence of the three periodontopathic microorganisms, P. gingivalis, F. nucleatum and T. forsythia, was significantly higher than that of the remaining three microorganisms.

CONCLUSIONS

These results support the hypothesis that in some patients, cross-reactivity of the immune response to bacterial HSPs including those of periodontal pathogens, with arterial endothelial cells expressing hHSP60 may be a possible mechanism for the association between atherosclerosis and periodontal infection.

Patient Attitudes to Sternotomy and Thoracotomy Scars

BACKGROUND

There are no data comparing patient attitudes to sternotomy and thoracotomy scars following surgery for congenital heart disease (CHD).

METHODS

Two hundred and one patients with a scar from CHD surgery (105 sternotomy, 36 thoracotomy, and 60 both scars) had a structured interview to explore attitudes to their scar.

RESULTS

Comparable proportions of each group reported that they did not like or hated their scar (23/105 [22 %] sternotomy, 9/36 [25 %] thoracotomy, 17/60 [28 %] both scars). Significantly more patients stated that they where embarrassed by and/or their choice of clothing was affected by a thoracotomy scar (20/36, 56 %) than those with a sternotomy scar (36/105, 34 %), p = 0.04. This was also seen when comparing sternotomy alone with both scars (36/105 [34 %] vs. 34/60 [57 %], p = 0.008).

CONCLUSIONS

Adults who have undergone surgery for CHD are more likely to have a negative attitude to a thoracotomy than a sternotomy scar. Before a change in surgical approach is considered based on patient preferences, the acceptability and psychological impact of the different scars following surgery needs formal study.

Life insurance and mortgage application in adults with congenital heart disease1

OBJECTIVE

To compare the outcome of life insurance and mortgage applications of adults with congenital heart disease (CHD) with controls and at different severities of CHD.

METHODS

Two hundred and ninety-nine adult CHD patients underwent a questionnaire-based interview by a trained nurse. They were asked to give an identical questionnaire to a friend to act as a control. One hundred and seventy-seven controls replied. CHD patients were classified into three categories based on severity. Comparisons were made between matched controls and between different severities of CHD.

RESULTS

Similar proportions of the CHD group (59%) had applied for life insurance as matched controls (56%). Compared to controls, significantly more of the adults with CHD who had applied for life insurance have been refused (34 vs 4%, P < 0.0001) or asked to pay extra (37 vs 6%, P = 0.0002). Mortgage application rate was also similar in both groups with more of the CHD patients refused than matched controls (20 vs 3%, P = 0.0004). These differences in both life insurance and mortgage remain significant when the cases and controls are matched by employment status and NYHA functional class. There was no significant difference in life insurance and mortgage application outcome between the groups of mild, significant and complex CHD.

CONCLUSIONS

Adults with CHD are significantly more likely to have difficulty obtaining life insurance or a mortgage than controls. Refusal rates appear to be independent of the severity of CHD. This suggests that the label of CHD may have a negative impact despite the lesion being minor and that the outcome of an individual application is difficult to predict based on the severity of the CHD. The increasing numbers of adults with CHD suggest that this problem is likely to increase and needs to be addressed as it can have a major impact on the patient's quality of life.

Ischemic stroke subtypes in Pakistan: the Aga Khan University Stroke Data Bank

OBJECTIVE

Frequency of ischemic stroke subtypes is influenced by ethnic and geographic variables. Our objective was to identify various stroke subtypes and its determinants at a tertiary care hospital.

METHODS

We prospectively collected data on ischemic stroke subtypes admitted to The Aga Khan University Hospital in Karachi.

RESULTS

A total of 596 patients were enrolled in 22 months in the Aga Khan Universtiy Stroke Registry. These included 393 patients with Ischemic stroke, 126 patients with intracerebral hemorrhage, 50 patients with subarachnoid hemorrhage and others. The ischemic stroke group was classified according to the TOAST criteria and comprised of lacunar 168/393 (42.7%); large artery atherosclerosis 106/393 (26.9%); cardioembolic 24/393 (6.1%); undetermined 80/393 (20.3%); and other determined types 15/393 (3.8%). The high proportion of lacunar strokes in our population may be due to high burden of inadequately treated hypertension and diabetes. Clear cut cardioembolic stroke was relatively infrequent in our population.

CONCLUSION

Lacunar stroke is the most common subtype of stroke in our patient population. This is most likely secondary to uncontrolled hypertension.

Management of transfusion-related acute lung injury with extracorporeal cardiopulmonary support in a four-year-old child

We report a case of successful management of transfusion-related acute lung injury (TRALI) with prolonged cardiopulmonary bypass support in a 4-yr-old patient undergoing elective cardiac surgery. TRALI was diagnosed clinically and immunologically by detection of reactive antibodies in a unit of fresh frozen plasma that had been administered to the patient. The aetiology and management of TRALI are briefly discussed and possible implications of this case for the management of TRALI are highlighted.

Defining a T-cell epitope within HSP 65 in recurrent aphthous stomatitis

The 65 kD heat shock protein (HSP) has been implicated in the aetiology of recurrent aphthous stomatitis (RAS). We have previously demonstrated that peptide 91-105 derived from the sequence of mycobacterial 65 kD HSP stimulates specifically lymphocytes from patients with RAS. In this investigation, we show that both CD4+ and CD8+ T cells were significantly stimulated with mycobacterial peptide 91-105. In contrast, the human homologous peptide 116-130 stimulated only CD4+ T cells. Inhibition studies showed that CD4+ T cells were class II restricted, whereas CD8+ T cells were class I restricted. We then used truncated or substituted peptides, and demonstrated that residues 95-105 appear to be important, and residue 104(Arg) critical, in stimulating the T cells. Thus, peptide 95- 105 may constitute a T-cell proliferative epitope in RAS. We postulate that the high load of micro-organisms that colonize the oral mucosa may initiate an immune response by the microbial HSP 65-derived peptide 95-105, stimulating the numerous Langerhans cells in the oral mucosa to activate a cross-reacting immune response to the homologous peptide 116-130 within the epithelial HSP 60, initiating the immunopathological changes that lead to RAS.

Experimental research photodynamic effects in perifocal, oedematous brain tissue

BACKGROUND

Photodynamic therapy (PDT) has been under discussion as additional treatment option for malignant gliomas. However, damage not only to tumour tissue but also to normal brain has been demonstrated. The mechanisms of this unwanted side effect have not yet been clearly identified. Spreading of photosensitiser with oedema after disruption of the blood-brain-barrier and potential sensitisation of normal tissue has been found previously. The present study investigates the time- and dose-dependency of normal tissue damage to photodynamic therapy using Photofrin II after disruption of the blood-brain-barrier.

METHODS

Male wistar rats anaesthetised with chloral hydrate were subjected to focal, cerebral cold lesions. Simultaneously, Photofrin II (PFII) was injected (2,5 or 5 mg/kg b.w.). Laser irradiation (630 nm) was performed after 4 h, 12 h and 24 h with varying light doses. Control groups were subjected to focal cold lesion alone, cold lesion with laser irradiation, PFII followed by laser irradiation, or laser irradiation alone (n=6 all groups). 24 h later, brains were removed for assessment of necrosis in coronal sections.

FINDINGS

Light dose had a significant impact on the extent of necrosis. Compared to control animals (lesion only: 0.84 +/- 0.2 mm2; lesion and irradiation alone: 0.7 +/- 0.3 mm2), the area of necrosis was increased to 2.8 +/- 0.5 (50 J/cm2), 3.5 +/- 1,1 (100 J/cm2) and 4.3 +/- 0.7 mm2 (200 J/cm2, 5 mg/kg b.w.; p<0.01). This effect was time-dependent. Maximal necrosis (6.3 +/- 1,6 mm2) was observed when brains were irradiated 12 h after PFII injection, with less necrosis occurring at 24 h (2.8 +/- 0.4 mm2, p<0.01). Reducing sensitiser dose to 2.5 mg/kg b.w. resulted in a reduction of necrosis (2.09 +/- 0.2 mm2, p<0.05).

INTERPRETATIONS

Damage to oedematous tissue after photodynamic therapy using i.v. PFII and laser light at 630 nm depends on laser dose, sensitiser dose and the time point of laser irradiation. The time point of PDT should be considered to prevent unwanted tissue reactions. In the clinical setting however, defined damage to peritumoural tissue may be advantageous. This should be achievable by optimised timing and dosage of photodynamic therapy.

The use of left heart bypass in adult and recurrent coarctation repair

OBJECTIVES

Paraplegia following coarctation repair occurs in 0.4% of infants. However, for older children, adults and re-operations, the incidence can be as high as 2.6%. Yet there is no consensus on the need for spinal cord protection or the optimal method. This paper reports our experience with left heart bypass (LHB) in adult and re-do coarctation.

METHODS

Between 1997 and 2000, nine patients underwent elective resection of coarctation (three re-dos, two balloons) with a mean age of 17.9 years (range, 8-44) and weight of 52 kg (range, 17.3-109). The mean trans-coarctation gradient was 29.6 mmHg (range, 20-45). Patients were placed on LHB using a centrifugal pump with full heparinization through a fourth-space thoracotomy. Patients were cooled to 31-34 degrees C for additional spinal cord protection. Repair was carried out with an inter-positional graft (5/9), a Gore-Tex patch (2/9) or end-to-end anastomosis (2/9). The mean cross-clamp and bypass times were 36.4 (range, 19-65) and 40.3 min (range, 22-70), respectively.

RESULTS

No patient developed transient or permanent paraplegia. The mean peak creatinine was 80 micromol/l (range, 51-123).

CONCLUSIONS

LHB is simple, easy and safe to implement, and is the only technique capable of maintaining independent upper and lower body perfusion pressure. Potentially, it provides the best spinal cord protection, and extends the margin of safety and time to execute an accurate repair.

Anomalous left coronary artery from the pulmonary artery: creating an autogenous arterial conduit for aortic implantation

Anomalous origin of the left coronary artery from the pulmonary artery requires surgical correction. A surgical technique is presented. Two infants underwent re-implantation of their anomalous left coronary arteries by creating a tunnel using autogenous aortic and pulmonary arterial walls. The advantage of this technique is that the new left coronary artery lies in the horizontal plane and in an anatomically correct axis running in the groove behind the pulmonary artery. It also provides a tension free endothelialized autogenous arterial walls with normal growth anticipated.

Hormonal control of arylhydrocarbon receptor (AhR) expression in the preimplantation rabbit uterus

We show that the arylhydrocarbon receptor (AhR) is localised in a distinct pattern in the preimplantation rabbit uterus. Employing immunohistochemistry, uteri from mature and immature rabbits were studied in different pregnancy stages during the preimplantation period (non-pregnant/estrous, pregnant and pseudopregnant) and following treatment with estradiol and progesterone, respectively. The staining patterns in pregnant and pseudopregnant rabbits were similar, indicating a primary maternal control of expression. A distinct change in AhR localization occurred in the endometrium of (1) non-pregnant compared with pregnant rabbits and (2) shortly prior to the anticipated time of implantation. Compared with non-pregnant uteri, the AhR was no longer restricted to a small cytoplasmic area apical to the nucleus but was found in the entire cytoplasm and in the nuclei of the endometrial epithelial cells in pregnant uteri. Prior to implantation, at day 6, stromal cells and the epithelium of the uterine glands, but no longer the luminal epithelial cells, were immunopositive. The estradiol-treated immature uteri showed a strong expression in the luminal epithelium and in some uterine glands, often with nuclear staining, while the estradiol-primed and progesterone-treated specimens had a similar staining pattern as mature preimplantation uteri. Present results demonstrate a distinct localization pattern of the AhR in the endometrium during the preimplantation period. Stage-specific changes in the expression pattern indicate control of AhR expression by maternal steroid hormones.

A policy of elective delayed sternal closure does not improve the outcome after arterial switch

BACKGROUND

Delayed sternal closure is regularly used in the immediate management of hemodynamic instability after neonatal cardiac procedures. The aim of this study was to assess whether the routine, elective use of delayed sternal closure would reduce morbidity in neonates undergoing arterial switch for transposition of the great arteries.

METHODS

A retrospective statistical analysis was performed on 52 neonates operated on from 1991 to 1998. Until 1994, chest closure was routinely attempted in all patients after arterial switch; the policy was then changed to delayed sternal closure in all cases in the latter half of the study period.

RESULTS

Delayed sternal closure did not significantly alter the mean duration of ventilation (2.7 +/- 2.37 versus 2.7 +/- 1.3 days) nor intensive care stay (4.1 +/- 2.8 versus 5.7 +/- 10.0 days; p = 0.46). There was no increase in the incidence of wound sepsis (7.7% versus 3.8%; p = 0.55), and mortality was unchanged (7.7% in both groups). There was an increase in the incidence of urgent reexploration (7.7% versus 19.2%; p = 0.22), which did not reach significance.

CONCLUSIONS

This study does not support the hypothesis that elective delayed sternal closure reduces the morbidity after arterial switch in neonates but does, however, confirm the safety and efficacy of the procedure.

A dual strategic approach to mega-aortic aneurysms

Staged resection of mega-aortas with Borst's two-stage elephant trunk (ETK) is the gold standard but has a higher mortality and morbidity compared to single-segment repair. We report the first case of combined surgical and covered-stent approach in Europe. Location and dilatation of the proximal landing zone accounts for the majority of failures in covered-stenting but an ETK is stable, easy to localise and gives an excellent seal. In high-risk cases where surgical resection is not offered, stenting is an option. The lack of a thoracotomy is an advantage in often-frail patients recovering from stage-I and shortens ITU-stay. Therefore, a combined approach is an acceptable alternative in selected individuals.

Measurement of CP-violating asymmetries in B0 decays to CP eigenstates

We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta = 0.34+/-0.20 (stat)+/-0.05 (syst).

Marfan's syndrome: a review

Marfan's syndrome is an inherited disorder of connective tissue, in which the most pronounced abnormalities occur in the musculoskeletal, cardiovascular and ocular systems. Aortic dilatation and dissection are the major causes of morbidity and mortality. Recent advances in surgical techniques and earlier intervention have reduced postoperative mortality and morbidity.

The major in vivo modifications of the human water-insoluble lens crystallins are disulfide bonds, deamidation, methionine oxidation and backbone cleavage

This investigation of the water-insoluble crystallins from human lenses has used multiple chromatographic separations to obtain proteins of sufficient purity for mass spectrometric analysis. Each fraction was analysed to determine the molecular masses of the constituent proteins as well as peptides in tryptic digests of these proteins. The major components of the water-insoluble crystallins were identified as alphaA- and alphaB-crystallins. In addition, gammaS-, betaB1-, gammaD-, betaA3/A1- and betaB2-crystallins were found, in order of decreasing abundance. Although there was evidence of some backbone cleavage, the predominant forms of alphaA-, alphaB, betaB2-, gammaS- and gammaD-crystallins were the intact polypeptide chains. The major modifications distinguishing the water-soluble crystallins were increased disulfide bonding, oxidation of Met, deamidation of Gln and Asn and backbone cleavage. Of the many reactions hypothesized to lead to crystallin insolubility and cataract, these results most strongly support metal-catalysed oxidation, deamidation and truncation as initiators of conformational changes that favor aggregation.

Donor organ transmission of varicella zoster due to cardiac transplantation

BACKGROUND

We report a case of donor-transmitted varicella zoster viral (VZV) infection in a cardiac transplant recipient. A 15-month-old girl developed primary VZV infection 12 days after cardiac transplantation. The donor suffered from varicella 2 weeks before death from pneumococcal meningitis.

METHODS

Despite treatment of the seronegative recipient with intravenous acyclovir from the time of surgery, she developed symptoms of fever, a nonspecific macular rash, and small palatal vesicles.

RESULTS

After rapid diagnostic confirmation by direct immunofluorescence on vesicular fluid, high-dose intravenous acyclovir was commenced. In addition, the cyclosporine dose was reduced by 25%. The child made a quick and uncomplicated recovery.

CONCLUSIONS

Donor organ transmission of VZV has not, to our knowledge, been previously reported. It occurred despite treatment with acyclovir and resulted in an atypical cutaneous eruption. It responded to an increased dose of acyclovir and a reduced level of immunosuppression.

Results in the operative treatment of elderly patients with intracranial meningioma

With life expectancy in the industrial nations increasing during recent years, the number of patients older than 70 years with intracranial tumours and, especially, meningiomas is rising. To evaluate the indications for operative treatment, we reviewed 66 patients older than 70 years who were operated upon for intracranial meningioma in our department between 1991 and 1997. The mean age was 75 years. The oldest patients were 86 years old. Thirteen patients with recurrent meningiomas were operated upon. The mortality rate was 7.6%. Neurological symptoms improved in 38 patients (57.6%), were unchanged in 11 (16.6%), and deteriorated in 12 (18.2%). Patients with recurrent meningiomas seem to have a higher operative risk and their outcome is worse than after a primary operation. In general, there were good postoperative results in patients with few concomitant diseases, small meningiomas, small edema, short time of operation, and accessible location (convexity rather than skull base). Age in general is not a contraindication for operation. In cases of incidental findings of small meningiomas, we recommend observation and MRI follow-up. Symptomatic meningiomas should be removed whenever there is an acceptable risk from an internal or anaesthesiological point of view.

The Ross procedure in children under ten years of age

BACKGROUND AND AIMS OF THE STUDY

The potential advantages of the Ross procedure in children under 10 years of age have yet to be validated. Concerns remain regarding progressive dilatation of the pulmonary autograft and potential homograft stenosis. We present our experience in this age population.

METHODS

A retrospective analysis of aortic root replacement using the Ross procedure in 11 young children (nine males, two females; median age 84 months; range 3 months to 10 years) between January 1996 and January 1999 was performed jointly in two pediatric surgical centers.

RESULTS

There were no operative deaths. Mean hospital stay was 12 +/- 4 days, and mean follow up 14.5 +/- 8 months. The event-free survival (death, reoperation, endocarditis, arrhythmia) was 100%. Currently, nine children are in NYHA functional class I, and two in class II. The autograft and homograft were evaluated by serial echocardiography. There was no sign of progressive dilatation of the autograft. Aortic regurgitation was trivial in four children and mild in seven. No growth of the autograft was noted; this was consistent with minimal somatic growth. Homograft peak gradients remained low during the follow up.

CONCLUSIONS

Although the pulmonary autograft procedure is more complex than other types of aortic valve replacement, it can be safely applied in children. Early follow up indicates satisfactory performance of the autograft. If dilatation will not occur, pulmonary root autograft may be an attractive substitute for diseased aortic valves in children.

Changing cyclosporin A formulation: an analysis in paediatric cardiac transplant recipients

Cyclosporin A is the primary immunosuppressive agent used in cardiac transplantation to maintain chronic immunosuppression. Absorption may be erratic and major side-effects include nephrotoxicity. A recently introduced formulation (Neoral) improves absorption in cystic fibrosis heart-lung transplant recipients, but episodes of rejection have been reported on conversion from the oil-based formulation. A retrospective analysis of 21 paediatric cardiac transplant recipients who had been converted from the oil-based formulation to the micro-emulsified formulation was performed. No clinical rejection episodes occurred following conversion. There was a significant reduction in dose following conversion (p < 0.001). The mean trough level was less on the new formulation (p = 0.04), but there was no difference in coefficient of variation or standard deviation. Mean glomerular filtration rate (GFR) was significantly less, but there was no difference in the rate of change of GFR on the new formulation. Erratic absorption and deteriorating renal function remain as significant problems in paediatric cardiac transplant recipients despite conversion to the new formulation.

Significance of Epstein-Barr virus status and post-transplant lymphoproliferative disease in pediatric thoracic transplantation

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is a serious complication of organ and bone marrow transplantation. The importance of EBV matching between recipient and donor remains unclear. Between October 1987 and December 1997, 64 pediatric cardio-pulmonary transplants were performed at this center (58 hearts, two heart/lungs, four sequential single lungs). The EBV viral capsid antigen (VCA) immunoglobulin G (IgG) status of both donor and recipient was determined at the time of transplant. Of 56 patients from whom paired sera was available for analysis, 27 (50%) were recipient and donor EBV IgG positive, four (7%) were recipient EBV IgG positive and donor EBV IgG negative, and 12 (20%) were recipient EBV IgG negative and donor EBV IgG negative. The remaining 13 (23%) patients were EBV IgG negative but received organs from EBV IgG-positive donors. The EBV immunoglobulin M (IgM) status was determined from 6 weeks post-transplant in the 11 mismatches who survived for longer than 28 d. Seven became EBV IgM positive, two remained EBV IgM negative; the status of the remaining two remains unknown. The EBV IgM status was also determined retrospectively in patients who were EBV IgG negative pretransplant and received organs from EBV IgG-negative donors. Nine became EBV IgM positive; the rest remained negative. PTLD was diagnosed in two of 56 patients from whom paired sera was available; one was donor and recipient EBV IgG negative; the other was donor and recipient EBV IgG positive. No cases of PTLD were diagnosed in the remaining eight patients from whom paired sera was not available. Our experience suggests that PTLD does not occur with any greater frequency in the 'mismatch' group, and does not justify EBV matching in pediatric thoracic transplantation where there is a higher proportion of EBV-negative recipients than in adults.

Synthesis of 5-substituted 2'-deoxycytidine 5'-(alpha-P-borano)triphosphates, their incorporationinto DNA and effects on exonuclease

Direct PCR sequencing with boronated nucleotides provides an alternative to current PCR sequencing methods. The positions of boranophosphate-modified nucleotides incorporated randomly into DNA during PCR can be revealed directly by exonuclease digestion to give sequencing ladders. Cytosine nucleotides, however, are especially sensitive to exonuclease digestion and provide suboptimal sequencing ladders. Therefore, a series of 5-substituted analogs of 2'-deoxycytidine 5'-(alpha-P-borano)triphosphates (dCTPalphaB) were synthesized with the hope of increasing the nuclease resistance of deoxycytosine residues and thereby enhancing the deoxycytosine band intensities. These dCTP analogs contain a boranophosphate modification at the alpha-phosphate group in 2'-deoxycytidine 5'-triphosphate (dCTP) as well as a 5-methyl, 5-ethyl, 5-bromo or 5-iodo substitution for the 5-hydrogen of cytosine. The two diastereomers of each new dCTP derivative were separated by reverse phase HPLC. The first eluted diastereomer (putatively Rp) of each dCTP analog was a substrate for T7 DNA polymerase (Sequenase) and had an incorporation efficiency similar to normal dCTP and dCTPalphaB, with the 5-iodo-dCTPalphaB analog being the least efficient. Substitution at the C-5 position of cytosine by alkyl groups (ethyl and methyl) markedly enhanced the dCTPalphaB resistance towards exonuclease III (5-Et-dCTPalphaB >5-Me-dCTPalphaB >dCTPalphaB approximately 5-Br-dCTPalphaB >5-I-dCTPalphaB), thereby generating DNA sequences that better define the deoxycytosine positions. The introduction of modified dCTPalphaB should increase the utility of direct DNA sequencing with boronated nucleoside 5'-triphosphates.

Early results with the Carbo-seal composite valve conduit for aortic root replacement

BACKGROUND AND AIMS OF THE STUDY

Composite graft replacement of the aortic root is still a complex operation, transgraft hemorrhage being one of the most severe complications. The aim of the study was to evaluate early results with the Carbo-seal composite conduit for aortic root replacement.

METHODS

A retrospective review of 21 patients operated on for ascending aortic aneurysm and/or dissection with the open technique between August 1993 and February 1998 is presented; 12 patients had Marfan syndrome and nine were non-Marfan.

RESULTS

There were two operative deaths (9.5%) due to low cardiac output. Two patients were re-explored for bleeding which was not due to transgraft hemorrhage. Postoperative complications were one hemothorax, one pneumothorax and two pericardial effusions. During the follow up, one patient died of rupture of a descending aortic aneurysm, and one patient in atrial fibrillation had a transient ischemic attack. At the closing of the follow up, the remaining patients were well and free of complications.

CONCLUSIONS

Carbo-seal may be considered a reliable device for use in aortic root replacement, though a longer follow up and a larger patient population are necessary to confirm these positive early results.

Empyema thoracis: a role for open thoracotomy and decortication

BACKGROUND

Thoracentesis and antibiotics remain the cornerstones of treatment in stage I empyema. The management of disease progression or late presentation is controversial. Open thoracotomy and decortication is perceived to be synonymous with protracted recovery and prolonged hospitalisation. Advocates of thoracoscopic adhesiolysis cite earlier chest drain removal and hospital discharge. This paper challenges traditional prejudice towards open surgery.

METHODS

A five year audit of empyema cases referred to a regional cardiothoracic surgical unit analysing previous clinical course, surgical management, and outcome.

RESULTS

Between February 1992 and February 1997, the number of referrals to this centre increased dramatically. Twenty-two children were referred for surgery (15 boys, seven girls; age range, 0.5-16 years). Before referral, patients had been unwell for 6-50 days (median, 15), had been treated with several antibiotics, and had undergone chest ultrasound (15 patients), computed tomography (five patients), pleural aspiration attempts (13 patients), and intercostal drainage (seven patients). The organism responsible was identified in only two cases (Streptococcus pneumoniae). Three patients had intraparenchymal abscess formation. Eighteen patients underwent open thoracotomy and decortication. Drain removal was performed on the first or second day. Fever resolved within 48 hours. Median hospital stay was four days. All patients had complete clinical and radiological resolution.

CONCLUSIONS

Treatment must be tailored to the disease stage. In stage II and III diseases, open decortication followed by early drain removal results in rapid symptomatic recovery, early hospital discharge, and complete resolution. In the early fibrinopurulent phase, alternative strategies should be considered. However, even in ideal cases, neither fibrinolysis nor thoracoscopic adhesiolysis can achieve more rapid resolution at lower risk.

HSP-derived peptides inducing uveitis and IgG and IgA antibodies

Heat shock protein (HSP) 65 kD-derived peptides, which specifically stimulate T cells from patients with Behçet's disease (BD), are capable of inducing uveitis in rats. Mycobacterial HSP 65 kD and BD-specific peptides were injected into Lewis rats and the development of uveitis was monitored clinically and histologically, and IgG and IgA antibodies were measured using an enzyme-linked immunosorbent assay (ELISA). Rats immunized with HSP peptides that developed uveitis showed significantly higher serum IgG antibody levels to peptide 311-326 (P < 0.05) and the corresponding homologous human peptide 336-351 (P < 0.01) than rats without uveitis. Significant increases in serum IgA antibodies in rats with uveitis were also observed in those immunized with peptides 111-125, 311-326 and 336-351 (P < 0.05). Rats injected with HSP 65 kD showed a rise in IgG antibody levels to peptides 111-125, 154-172 and 311-326 and to a lesser extent, a rise in IgA antibody level to peptide 311-326. HSP showed almost complete inhibition of binding of IgG antibodies to HSP 65 kD, but peptides 111-125, 154-172, 311-326 and 336-351 showed inhibition to a lesser extent in a competitive assay. These results suggest that increases in IgG and IgA antibody levels to specific peptides within HSP, develop in rats with uveitis. The T and B cell epitopes responsible for the development of ocular disease in rats immunized with HSP-derived peptides, appear to be similar or identical to those found in patients with the ocular type of BD.

Experimental mucosal induction of uveitis with the 60-kDa heat shock protein-derived peptide 336-351

Subcutaneous (s.c.) immunization of rats with the human 60-kDa heat shock protein (HSP)-derived peptide 336-351 induced clinical and/or histological uveitis in 80 % of rats. Subsequent experiments to prevent the development of uveitis by oral or nasal administration of the peptide have failed. Instead, uveitis was induced in 74.6 % of rats given the peptide orally (5 times), in 75 % given the peptide nasally (5 times) or 91.7 % of those administered the peptide by both routes (10 times). Histological examination showed that any one route of administration of the peptide elicited iridocyclitis in 42.2 % but loss of photoreceptors only in 4.9 % of rats. In contrast, sequential administrations of the peptide by a combined mucosal-s.c. route resulted in iridocyclitis in only 25 % but loss of photoreceptors in 40 % of animals. Examination of mRNA from CD4-enriched splenic cells by reverse transcription-PCR failed to yield significant differences in Th1 or Th2 cytokines. Treatment with monoclonal antibody (mAb) to CD4 yielded a dose-dependent decrease in uveitis from 82 % to 25 %. Similarly, treatment with IL-4 significantly decreased the development of uveitis from 68 % to 30.4 %. Conversely, treatment of the rats with mAb to CD8 greatly enhanced the onset of uveitis (from about 22 days in the controls to 11 days) and all the rats developed uveitis by day 24. Thus, CD4+ cells mediate, whereas CD8+ cells suppress the development of uveitis. We suggest that this novel experimental mucosal model of induction of uveitis by the human 60-kDa HSP-derived peptide 336-351, which is specific in stimulating T cell responses in Behcet's disease, is consistent with the oro-genital onset of this disease and the development of uveitis.

Benign transient hyperphosphatasemia of infancy and early childhood following cardiac transplantation

The phenomenon of a transient very high rise in serum alkaline phosphatase, associated with either trivial illness or no symptoms, in early childhood has been described previously in otherwise normal children. We describe here what we believe are the first published reports in two children who have previously undergone orthotopic cardiac transplantation. They were found to have a very high serum alkaline phosphatase, with features consistent with a diagnosis of transient hyperphosphatasemia of infancy and early childhood. The importance of early recognition and avoidance of overinvestigation are discussed.