Ultrastructure of iodine treated wood

Iodine staining has been used to study the orientation of cellulose microfibrils in wood using light microscopy. The aim of this work was to understand the exact nature of the staining reaction with iodine and to provide insight into the properties and organisation of the wood cell wall. Based on transmission electron microscopy it is apparent that precipitation of the iodine following treatment with nitric acid results in the formation of crystal cavities within the cell wall, which follow the orientation of the cellulose microfibrils. There is no evidence that iodine precipitates within “drying checks” as previously speculated. High resolution confocal reflectance microscopy of crystal cavity orientation indicates that the microfibril arrangement within pit borders can be both spiral and circular. Crystal cavities are much more abundant within the S1 layer than elsewhere. All of the cells examined had crystal cavities in the S1 region, which may be related to the reduced lignification at the S1/S2 boundary resulting in greater porosity of the cell wall at this location. Within the S2 region, clusters of crystal cavities are randomly distributed and occur in widely varying numbers among adjacent cell walls, suggesting variations in the porosity of the S2 wall within and among adjacent tracheids. Cavities form preferentially within more electron lucent regions of the cell wall. The random nature of crystal cavity formation within S2 clusters probably reflects the underlying random nature of the cell wall nanostructure. We conclude that iodine staining can provide important clues to the nanostructural properties of tracheid cell walls.

Evaluation of Carolina Rinse solution as a treatment for ischaemia reperfusion of the equine jejunum

REASONS FOR PERFORMING STUDY

Ileus and peritoneal adhesions are the most common complications following surgery for small intestinal obstruction. Carolina Rinse (CR) has been shown to decrease reperfusion injury in intestine and other organs.

HYPOTHESIS

CR decreases intestinal inflammation and subsequent scarring associated with reperfusion injury.

METHODS

CR was infused intra-arterially and applied topically just prior to reperfusion in jejunum exposed to experimental ischemia. Vascular permeability, neutrophil accumulation and serosal scarring were compared in treated and untreated intestine.

RESULTS

CR maintained a normal osmotic reflection coefficient and decreased migration of neutrophils into the serosa during reperfusion. After 10 days, treated intestine was normal in appearance with a trend toward less serosal scarring and fibroblast proliferation. There was a significant decrease in fibroplasia at biopsy sites in treated intestine.

CONCLUSIONS

Arterial perfusion combined with topical application of CR during jejunal ischaemia decreases immediate reperfusion injury and limits post operative scarring.

POTENTIAL RELEVANCE

CR should be used as a local perfusate rather than a systemic treatment; it may best be applied topically and intraluminally to avoid damaging mesenteric arteries. CR should be considered an adjunct treatment as part of overall surgical management and post operative care.

Assembly of fluorescent chimeric virus-like particles of canine parvovirus in insect cells

Canine parvovirus (CPV) is a small non-enveloped ssDNA virus composed of the viral proteins VP1, VP2, and VP3 with a T=1 icosahedral symmetry. VP2 is nested in VP1 and the two proteins are produced by differential splicing of a primary transcript of the right ORF of the viral genome. The VP2 protein can be further proteolytically cleaved to form VP3. Previous studies have shown that VP1 and VP3 are unnecessary for capsid formation and consequently, that VP2 alone is sufficient for assembly. We have hypothesized that insertion of the enhanced green fluorescent protein (EGFP) at the N-terminus of VP2 could be carried out without altering assembly. To investigate the possibility to develop fluorescent virus-like particles (fVLPs) from such chimeric VP2 proteins, the corresponding fusion construct was abundantly expressed in insect cells. Confocal imaging indicated that the EGFP-VP2 fusion product was assembled to fluorescent capsid-like complexes. In addition, electron micrographs of purified EGFP-VP2 complexes showed that they displayed a very similar size and appearance when compared to VP2 VLPs. Further, immunolabelling of purified EGFP-VP2 VLPs showed the presence of EGFP within the structure. Fluorescence correlation spectroscopy (FCS) studies confirmed that fVLPs were very similar in size when compared to authentic CPV. Finally, feeding of mammalian cells susceptible to CPV infection with these fVLPs indicated that entry and intracellular trafficking could be observed. In summary, we have developed fluorescent virus-like nanoparticles carrying a heterologous entity that can be utilized as a visualization tool to elucidate events related to a canine parvovirus infection.

Clinical evaluation of a continuous oxygen consumption monitor in mechanically ventilated patients

We measured oxygen consumption using a new noninvasive modular metabolic monitor, M-COVX trade mark, in ventilated critically ill patients. Oxygen consumption was measured continuously as part of routine monitoring for up to 24 h following mechanical ventilation in 27 patients admitted to a general intensive care unit. We explored several possible sources of error. Most errors related to inaccurate tidal volume measurement, which resulted in rejection of a median 14% (interquartile range 8-34%) of data. Water accumulation in the pneumotachograph was responsible and occurred more frequently with water bath humidifiers. After manual removal of erroneous data mean oxygen consumption values were virtually identical to calculated values in 24 of 27 patients. We conclude that in most ventilated patients averaging of continuous oxygen consumption data with the M-COVX module results in small errors.

[The meaning and implementation of clinical governance]

Under the 1999 Health Act a statutory duty of "quality" was given to National Health Service (NHS) organisations in the United Kingdom. This was matched by a comprehensive quality program. In this paper we look at the meaning of clinical governance as a mechanism for ensuring local delivery of high quality clinical care in the UK, the national structures which have been put in place to develop, reinforce and implement clinical governance and the role of the NHS Clinical Governance Support Team (CGST) in delivering clinical governance "on the ground". As part of the quality program, the CGST is working to enable national clinical governance policy to be translated into practice locally by supporting the development of better ways of working by individuals, clinical teams and health organisations to deliver a continuous, integrated approach to quality healthcare for patients.

Disease emergence and health transitions in the last millennium

For most of the first millennium, average expectation of life was only 30 or 40 years. The beginning of the 20th century saw the start of improvements, which by the century's end meant that a baby boy could expect an average 75 years of life, a baby girl even longer. The successes of the 20th century were not products of advances in medicine alone, but consequences of the great sanitary reforms that fuelled the public health movement in late Victorian Britain. However, health challenges also grew and changed: the rise in so-called modern epidemics (coronary heart disease, cancer, accidents and mental illness); the ageing of the population; the containment of the costs of rapid technological advances; the marked and intractable inequalities in health status between rich and poor, and between North and South. The dawn of a new millennium sees many of these health problems carried over from the late 20th century, whilst communicable diseases, once thought conquered, continue to pose a serious threat to human health because of their global significance. This paper traces progress in the health of the population and identifies some of the key challenges for medicine in the 21st century.

A psychotherapist in the house: a service for distressed junior doctors

A service set up specifically for junior doctors is described. Doctors used the confidential psychotherapy service for both work-related and personal issues. Job-related issues predominated. Common psychodynamic problems underlying relationship difficulties and workload pressures are described and lessons learned from the experience noted.

Adult Attachment Interview: linkages with dimensions of emotional availability for mothers and their pre-kindergarteners

Maternal attachment representations were assessed using the George, Kaplan, and Main (1985) Adult Attachment Interview (AAI), and emotional availability during observed mother-child interactions was assessed using the third edition of the Emotional Availability (EA) Scales (Biringen, Robinson, & Emde, 1998). This edition of EA included four parental scales and two child scales (Maternal Sensitivity, Structuring, Nonintrusiveness and Nonhostility; and Child Responsiveness and Child Involvement). Separate Hierarchical Multiple Regressions (HMRs) were computed to examine the prediction of the separate EA dimensions from demographic information, the AAI classification, and AAI scales. These analyses indicated that each of the EA dimensions (with the exception of maternal nonintrusiveness and nonhostility) was predicted by the AAI classification and/or AAI scales. Using three-step HMRs, the strongest prediction was for maternal sensitivity where 54% of the total variance in maternal sensitivity was explained by maternal education, AAI classification, and AAI 'state of mind' scales. Maternal nonhostility was predicted by maternal education and gender of the child, with lower-income mothers and mothers of girls demonstrating greater hostility.

Continuing improvement in cadaver donor graft survival in North American children: the 1998 annual report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

This report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) covers the years 1987-1997, and analyses data on 3,133 cadaver donor (CD) transplants performed in 2,736 patients. There has been a steady decline in the number of CD transplants in children since 1996. Kidneys recovered from donors under 10 years of age accounted for 35% of all transplants in 1987, whereas by 1996 they comprised less than 20%. Caucasian children received 54% of CD transplants, whereas African-American children received 21%. Children under 6 years of age received 17% of CD transplants. Approximately half (46%) of the patients were induced with a T-cell antibody, and at 7 years post-transplant triple therapy is used in 70% of those with a functioning graft. Cyclosporin A is the primary immunosuppressant, with 92% of the patients being maintained on it at 5 years post-transplant. Among patients receiving a transplant in 1997, 11% were initiated with another calcineurin inhibitor, tacrolimus. At 15 days post-transplant 20% of the patients have had a rejection episode and by day 45, 46% have had an acute rejection. The probability of developing a rejection within the first year was reduced from 71% in 1987-1988 to 47% in 1995-1996.

A decade of living donor transplantation in North American children: the 1998 annual report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

This report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) covers the years 1987-1997, and analyzes data on 2,904 living donor (LD) transplants performed in 2,779 patients. Since 1991, approximately 300 LD transplants have been performed each year at the participating centers of the NAPRTCS. Caucasian children account for 72% of all LD recipients while African-American children constitute only 11%. There has been a gradual decline in the number of transplants performed in children under the age of 6 years from a peak of 30% in 1987, to 21% in 1997. Preoperative calcineurin inhibitor therapy has dropped from 71% in 1987 to 38% in 1997. Through 1996, at six months post-transplant 97% of recipients were receiving prednisone, 88% were maintained on cyclosporin A, and 79% were receiving azathioprine. Of patients transplanted in 1997, 47% are maintained on mycophenolate and 10% are maintained on tacrolimus. By day 15, 20% of index transplant patients have had an acute rejection and by the end of the first year 47% have had a rejection episode. Among patients transplanted in 1995-1996, 40% had a rejection in the first year. Nine per cent of rejection episodes are irreversible in children under 2 years of age and 5% of the episodes are irreversible in 25-year-old children. Estimated graft survival probability at 1 year is 91%, at 3 years it is 84% and at 5 years it is 78.5%. Rejection accounts for 33% of graft loss and recurrence constitutes another 10%. Influential prognostic variables for graft survival are race (African-American vs. others, relative risk (RR) = 2.0, p < 0.001), > 5 random transfusions (RR = 1.6, p < 0.001, T cell induction therapy (RR = 0.78, p = 0.01), and later year of entry (1989-1990 vs. 1994-1995, RR = 0.95, p = 0.04). Patient survival at 1 and 3 years was 97% and 96.5%, respectively, however, the 3-year patient survival of children under 2 years was 89%. The mean height deficit baseline (n=2,677) was -1.86, at 1 year post-transplant (n=1,459) it was -1.80, and at 5 years post-transplant (n=592) it was -2,06. This report, devoted specifically to LD pediatric transplants, raises the issues regarding the use of immunosuppression such as preoperative calcineurin inhibitors and T-cell antibodies. Studies to address the high incidence of chronic rejection and recurrence of original disease are necessary. Additional areas of concern are the high infant mortality and continued growth retardation post-transplantation.

Solution structure of the MEF2A-DNA complex: structural basis for the modulation of DNA bending and specificity by MADS-box transcription factors

The solution structure of the 33 kDa complex between the dimeric DNA-binding core domain of the transcription factor MEF2A (residues 1-85) and a 20mer DNA oligonucleotide comprising the consensus sequence CTA(A/T)(4)TAG has been solved by NMR. The protein comprises two domains: a MADS-box (residues 1-58) and a MEF2S domain (residues 59-73). Recognition and specificity are achieved by interactions between the MADS-box and both the major and minor grooves of the DNA. A number of critical differences in protein-DNA contacts observed in the MEF2A-DNA complex and the DNA complexes of the related MADS-box transcription factors SRF and MCM1 provide a molecular explanation for modulation of sequence specificity and extent of DNA bending ( approximately 15 versus approximately 70 degrees ). The structure of the MEF2S domain is entirely different from that of the equivalent SAM domain in SRF and MCM1, accounting for the absence of cross-reactivity with other proteins that interact with these transcription factors.

Pretransplant dialysis status and outcome of renal transplantation in North American children: a NAPRTCS Study. North American Pediatric Renal Transplant Cooperative Study

BACKGROUND

There are no large studies of the effect of pretransplant dialysis status on the outcome of renal transplantation (Tx) in children. This study evaluated the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) registry data for the outcome of Tx in pediatric patients who either (1) received their transplants preemptively or (2) were maintained on dialysis before receiving their transplants.

METHODS

We compared graft survival and patient survival rates, incidence of acute tubular necrosis (ATN), acute rejection episodes, and causes of graft failure in peritoneal dialysis (PD) patients with those maintained on hemodialysis (HD) and those undergoing preemptive Tx (PTx).

RESULTS

Primary Tx was performed in 2495 children (59% male; 61% Caucasian; 1090 PD, 780 HD, 625 PTx) between 1/1/1992 and 12/31/1996. The overall graft survival rates of the PD and HD groups were similar, but were less than that of the PTx group (3-year: 82% PD and HD, 89% PTx, overall P = 0.0003). Improved graft survival in the PTx group was present only in recipients of grafts from living donors. There was no difference in the overall patient survival rate at 3 years, or in time to first acute-rejection episodes in the three groups. The incidence of ATN in the first 7 days post-Tx was higher in PD and HD patients than in PTx patients (11% PD and 12% HD vs. 2% PTx, P<0.001; HD vs. PD, P = NS). The major single cause of graft failure in each group was: PD, vascular thrombosis (200%); HD, chronic rejection (27%); PTx, acute and chronic rejection (21% each).

CONCLUSION

NAPRTCS data show that graft survival is improved in patients receiving PTx, compared with those receiving PD and HD. Graft loss resulting from vascular thrombosis is more common in children who receive PD than in those receiving HD.

Temporal variability in birth prevalence of cardiovascular malformations

OBJECTIVE

To investigate changes over time in the prevalence at live birth of cardiovascular malformations and to compare "anatomical" and "physiological" diagnostic hierarchies within a population.

DESIGN

Retrospective and prospective ascertainment of all congenital cardiovascular malformations diagnosed in infancy.

SETTING

The resident population of one health region.

PATIENTS

All infants live born from 1985 to 1997 with cardiovascular malformations confirmed by echocardiography, cardiac catheterisation, surgery or autopsy.

MAIN OUTCOME MEASURES

Year to year variation in prevalence of individual malformations and of "complex", "significant", and "minor" groups.

RESULTS

2671 babies with cardiovascular malformations were confirmed in a denominator population of 477 960 live births (5.6 per 1000). There was no change over 13 years in the birth prevalence of "complex" or "significant" defects, but a highly significant increase in "minor" defects (p < 0.0001), mainly small ventricular septal defects. Termination of pregnancy increased from no cases in 1985 to 16 in 1997 with no demonstrable effect on live born babies with heart defects. A one dimensional "anatomical" diagnostic hierarchy led to under ascertainment of pulmonary atresia by 27%, coarctation of the aorta by 39%, and interruption of the aorta by 100%.

CONCLUSIONS

The apparent increase in live born cardiovascular malformations results mainly from improved diagnosis of minor defects. There has been no change over time in birth prevalence of more serious defects. Spontaneous year to year variation in numbers will make it difficult to ascribe any short term changes to any particular intervention. A two dimensional diagnostic hierarchy is offered as a standard.

Sequential assignment of proline-rich regions in proteins: application to modular binding domain complexes

Many protein-protein interactions involve amino acid sequences containing proline-rich motifs and even polyproline stretches. The lack of amide protons in such regions complicates assignment, since 1HN-based triple-resonance assignment strategies cannot be employed. Two such systems that we are currently studying include an SH2 domain from the protein Crk with a region containing 9 prolines in a 14 amino acid sequence, as well as a WW domain that interacts with a proline-rich target. A modified version of the HACAN pulse scheme, originally described by Bax and co-workers [Wang et al. (1995) J. Biomol. NMR, 5, 376-382], and an experiment which correlates the intra-residue 1Halpha, 13Calpha/13Cbeta chemical shifts with the 15N shift of the subsequent residue are presented and applied to the two systems listed above, allowing sequential assignment of the molecules.

Slit-scanning confocal microendoscope for high-resolution in vivo imaging

We discuss the design and construction of a novel imaging system in which a fiber-optic imaging bundle and miniature optical and mechanical components are used to allow confocal fluorescence microscopy in remote locations. The instrumentation has been developed specifically for cellular examination of tissue for optical biopsy. Miniaturization of various components makes the device usable in a clinical setting. The numerical aperture of the beam in the tissue is 0.5, and the field of view is 430 microm. The measured lateral resolution of the system is 3.0 microm. The axial point and the axial planar response functions of the confocal system were measured with a FWHM of 10 and 25 microm, respectively. In vitro and in vivo images obtained with cell cultures, human tissue specimens, and animal models indicate that the performance of the device is adequate for microscopic evaluation of cells.

Association between outcome and telomere DNA content in prostate cancer

PURPOSE

To perform an initial retrospective investigation of the relationship between outcome in patients with organ confined prostate adenocarcinoma and the tumor cells' content of telomere DNA.

MATERIALS AND METHODS

The case-controlled study group was composed of eighteen men diagnosed with prostatic adenocarcinoma prior to 1993. The group was selected so that approximately one half died within ten years of diagnosis and one half survived ten years or longer. Archival, paraffin-embedded tumor tissue was recovered for each patient. DNA was extracted from newly cut sections, fixed to nylon membranes and hybridized with P32-labeled centromere- and telomere-specific probes. Telomere DNA contents were quantitated from the hybridized radioactivities. The relationships between telomere DNA content and survival, and telomere DNA content and disease recurrence in men receiving prostatectomies were determined.

RESULTS

Death and disease recurrence were associated with reduced telomere DNA content (p <0.0001, p <0.0001, respectively).

CONCLUSIONS

Telomere DNA content may differentiate high-risk patients with metastatic prostate cancer from men with indolent disease who can be spared the unnecessary side effects and expense of treatment by management with "watchful waiting."

Association between outcome and telomere DNA content in prostate cancer

PURPOSE

To perform an initial retrospective investigation of the relationship between outcome in patients with organ confined prostate adenocarcinoma and the tumor cells' content of telomere DNA.

MATERIALS AND METHODS

The case-controlled study group was composed of eighteen men diagnosed with prostatic adenocarcinoma prior to 1993. The group was selected so that approximately one half died within ten years of diagnosis and one half survived ten years or longer. Archival, paraffin-embedded tumor tissue was recovered for each patient. DNA was extracted from newly cut sections, fixed to nylon membranes and hybridized with P32-labeled centromere- and telomere-specific probes. Telomere DNA contents were quantitated from the hybridized radioactivities. The relationships between telomere DNA content and survival, and telomere DNA content and disease recurrence in men receiving prostatectomies were determined.

RESULTS

Death and disease recurrence were associated with reduced telomere DNA content (p <0.0001, p <0.0001, respectively).

CONCLUSIONS

Telomere DNA content may differentiate high-risk patients with metastatic prostate cancer from men with indolent disease who can be spared the unnecessary side effects and expense of treatment by management with "watchful waiting."

Paediatric community vision screening--a new model

The purpose of this study was to establish if a community based model using a Hospital Optometrist and Community Orthoptist can provide a practical secondary vision screening service for children. These professionals working in an Inner London Health Centre, assessed children who had failed primary vision screening. In total 483 new patients were seen between April 1994 and March 1996 with the largest referral source being the school nurse screening programme. The majority were managed by the team with a total onward referral rate to the Hospital Eye Service of 14%. In 78% of these cases the consultant's diagnosis agreed with the reason for referral. Where the consultant's diagnosis differed the children were identified as normal or a variant of normal. This model of care provides a 'one stop service' where a child identified as having a potential visual problem at primary screening can be assessed, refracted and provided with spectacles in a local setting without hospital referral. Referrals to the Hospital Eye Service are considerably reduced and a convenient service is provided for parents and children.

Impact of transfusions and acute rejection on posttransplantation donor antigen-specific responses in two study populations. Cooperative Clinical Trial in Transplantation Research Group

BACKGROUND

We participated in a protocol supported by the National Institutes of Allergy and Infectious Disease, Cooperative Clinical Trial in Transplantation (CCTT), which was designed to investigate the effect of peritransplant donor-specific transfusion in non-HLA-identical living donor kidney recipients.

METHODS

We determined the donor antigen-specific responses at 1 year after transplantation for the 79 CCTT donor-recipient combinations in this study. A lower rate of donor antigen-specific hyporeactivity was seen in the CCTT recipients (6 of 79=8%) versus our recipients at the University of Minnesota who underwent transplantation in the same period (9 of 55=16%, P=0.16) and versus our combined historical data (33 of 131=25%, P=0.002). Therefore, we studied the differences in the two recipient populations to determine why hyporeactivity was lower in the CCTT group than at our center.

RESULTS

Significant differences were seen in the acute rejection rates and the frequency of pretransplantation random transfusion. Overall and early (<3 month) acute rejection rates were higher in CCTT versus Minnesota recipients (overall: 51% vs. 20%, P=0.001) (early: 43% vs. 16%, P=0.001). The frequency of pretransplantation random transfusion was 40% for CCTT recipients (34%) versus 80% for Minnesota recipients (75%) (P=0.0004).

CONCLUSIONS

These results provide provocative, although not conclusive, evidence for the importance of pretransplantation transfusion and acute rejection episodes in the development of donor antigen-specific hyporeactivity. Pre-, peri-, and posttransplantation clinical events undoubtedly have an impact on posttransplantation immune parameters.

The medical expert witness: time to regulate conflicts of interest

Doctors are often asked to provide expert evidence for the courts. Whilst there is a considerable body of work in the legal literature, there is relatively little discussion and guidance in general medical literature. This is important as more doctors are drawn into the legal arena, and their ability to assist the court is a matter of consequence. The potential adverse effects in terms of the human, psychological and financial costs to the litigant parties, and the speed of access to justice, are considerable if the work is not done properly. Possible solutions to the present system are discussed and a set of guiding principles for acting as an expert witness is proposed.

Steady improvement in short-term graft survival of pediatric renal transplants: the NAPRTCS experience

This report of pediatric renal transplantation covers the years 1987-1998. Since its inception in 1987, the NAPRTCS has collected data on 6,038 transplants performed in 5,516 patients provided by 73 renal centers across the country. FSGS, together with developmental lesions of dysplasia and obstructive uropathy, account for 40% of all transplants. There has been a steady increase in the use of LD donors among children with 54% of all transplants in 1996 and 1997 being live-related. About 72% of LD transplants are performed in Caucasian children, with African-American children unfortunately receiving a disproportionate percentage of CD kidneys. There has been a steady decline in the use of CD kidneys recovered from young individuals and a gradual decline in the number of transplants performed in young recipients (< 6 years old). Graft survival for LD recipients was 91%, 84% and 79% at one, 3 and 5 years, respectively, and the comparative figures for CD recipients were 81%, 72% and 64%, respectively. Acute and chronic rejections account for most of the graft losses, with chronic rejection accounting for more than 30%. There has been a steady improvement in one-year graft survival of CD recipients with the 1997-1998 cohort exhibiting an improvement of 16% over the 1987-1988 cohort. This improvement has been brought about by eliminating the use of infant donor kidneys, reducing the number of random transfusions and increasing the maintenance dose of cyclosporine. Posttransplant growth continues to be poor, with catch-up growth being exhibited only in children under age 6.