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Biomedical subjects

D V Milford

Publications and source records attributed to D V Milford.

At least 19 recordsLinked to original sources

Skin surveillance of a U.K. paediatric transplant population.

BACKGROUND: Solid organ transplant recipients are at increased risk of skin cancer. Melanoma is less common than nonmelanoma skin cancer (NMSC) although the relative proportion of melanoma among skin cancers has been shown to be higher in paediatric than adult recipients. Multiple melanocytic naevi and/or atypical naevi may be a risk factor for the development of melanoma. The relationship between naevus counts and phenotypic characteristics, disease-related variables and sun exposure has not been explored in paediatric transplant patients. OBJECTIVES: To determine the prevalence of premalignant and malignant skin lesions and to identify known risk factors associated with benign and atypical melanocytic naevi in a U.K. paediatric transplant population. METHODS: Paediatric (< or = 19 years) renal and liver transplant patients, who were 5 or more years post-transplantation, were reviewed over 12 months. Lifetime history of sun exposure, episodes of sunburn, sunny holidays, sunscreen use, sun bed use, demographic and transplantation details were collected using interview, questionnaire and case note review. A skin examination was performed for regional counts of malignant lesions, benign and atypical naevi. RESULTS: Ninety-eight patients (82 liver, 13 renal, three multiorgan) with a median follow up of 9 years (range 5-16) were reviewed. Neither skin cancer nor premalignant lesions for NMSC were detected in this group. Eighty-five patients had benign naevi (median 6, range 1-57). Clinical risk factors for increased counts of benign naevi included increasing age (P = 0.03), more episodes of sunburn (P = 0.003) and prolonged treatment with cyclosporin (P = 0.009). The presence of atypical naevi in six patients was significantly associated with more episodes of sunburn (P = 0.006) and more transplants (P = 0.04). Other variables including phenotype, skin type, sun exposure, holidays abroad, residence abroad and total duration of immunosuppression did not correlate with benign or atypical naevus counts. CONCLUSIONS: Skin cancer was not observed in paediatric solid organ transplant recipients who were 5-16 years post-transplantation. Both benign and atypical naevus counts were higher in children with frequent episodes of sunburn. As both naevi and sunburn are risk factors for melanoma, we should target fair-skinned transplant recipients with naevi for intensive sun avoidance education. A prospective, longitudinal follow-up study should determine the onset of skin cancer post-transplantation and the significance of benign and atypical naevus counts in this cohort.

Adolescent↗

A prospective, randomized, multicenter trial of tacrolimus-based therapy with or without basiliximab in pediatric renal transplantation.

In a 6-month, multicenter, randomized, controlled, open-label, parallel-group trial, we investigated the efficacy and safety of adding basiliximab to a standard tacrolimus-based regimen in pediatric renal transplant recipients. Patients < 18 years received tacrolimus/azathioprine/steroids (TAS, n = 93) or tacrolimus/azathioprine/steroids/basiliximab (TAS + B, n = 99). Target tacrolimus levels were 10-20 ng/mL between days 0-21 and 5-15 ng/mL thereafter. Steroid dosing was identical in both groups. Basiliximab was administered at 10 mg (patients < 40 kg) or 20 mg (patients > or = 40 kg) within 4 h of reperfusion; the same dose was repeated on day 4. Biopsy-proven acute rejection rates were 20.4% (TAS) and 19.2% (TAS + B); steroid-resistant acute rejection rates were 3.2% and 3.0%, respectively. Patient survival was 100%; graft survival rates were 95% in both arms. The nature and incidence of adverse events were similar in both arms except toxic nephropathy and abdominal pain, which were significantly higher in the TAS + B arm (14.1% vs. 4.3%; p = 0.03 and 11.1% vs. 2.2%; p = 0.02; respectively). Median serum creatinine concentrations at 6 months were 86 micromol/L in the TAS and 91 micromol/L in the TAS + B arm; glomerular filtration rate was 79.4 and 77.6 (mL/min/1.73 m2), respectively. Adding basiliximab to a tacrolimus-based regimen is safe in pediatric patients, but does not improve clinical efficacy.

Adolescent↗

Renal function following liver transplantation for unresectable hepatoblastoma.

Combination of cyclosporine (CsA) and tacrolimus immunosuppression post-liver transplantation (LT) and the chemotherapeutic drugs used to treat hepatoblastoma (HB), are nephrotoxic. We aimed to determine the severity and duration of nephrotoxicity in children following LT for unresectable HB. We reviewed all children undergoing LT for unresectable HB at the Liver Unit, Birmingham Children's Hospital, UK, from 1991 to July 2000. Thirty-six children undergoing LT for biliary atresia, matched for age and sex, were selected as controls to compare pre- and post-LT renal function. Renal function was determined by estimation of glomerular filtration rate (eGFR) derived from plasma creatinine using Schwartz's formula. Twelve children with HB (mean age of diagnosis 33 months) who underwent LT (mean age 47 months) and 36 controls (mean age of LT 34 months) were studied. CsA was the main immunosuppressive drug used in each group. The median eGFR before, and at 3, 6, 12, 24 and 36 months after LT in HB group was significantly lower than controls (93 vs. 152, 66 vs. 79, 62 vs. 86, 66 vs. 87, 64 vs. 94, 53 vs. 90 mL/min/1.73 m2, respectively; 0.01 < p < 0.03). The reductions in the median eGFR of both the HB group and controls before and at 36 months after LT were 49 and 41%, respectively. At 36 months after LT, there was a trend for partial recovery of the eGFR in the controls but not in the HB group. Children who underwent LT for unresectable HB had renal dysfunction before transplantation that persisted for 36 months after LT.

Adolescent↗

Hypertension: a cause of growth impairment.

The effects of high blood pressure on growth are not fully understood and while hypertension may be associated with failure to thrive, hypertension causing failure to thrive in children is poorly documented. We describe four children presenting with failure to thrive due to hypertension consequent to various aetiologies. Control of hypertension with appropriate therapy resulted in improved growth. The exact pathogenesis of failure to thrive in hypertensive children is not known. These cases demonstrate the importance of careful measurement of blood pressure in children with failure to thrive.

Body Height↗

Human hypertension caused by mutations in WNK kinases.

Hypertension is a major public health problem of largely unknown cause. Here, we identify two genes causing pseudohypoaldosteronism type II, a Mendelian trait featuring hypertension, increased renal salt reabsorption, and impaired K+ and H+ excretion. Both genes encode members of the WNK family of serine-threonine kinases. Disease-causing mutations in WNK1 are large intronic deletions that increase WNK1 expression. The mutations in WNK4 are missense, which cluster in a short, highly conserved segment of the encoded protein. Both proteins localize to the distal nephron, a kidney segment involved in salt, K+, and pH homeostasis. WNK1 is cytoplasmic, whereas WNK4 localizes to tight junctions. The WNK kinases and their associated signaling pathway(s) may offer new targets for the development of antihypertensive drugs.

Amino Acid Sequence↗

Cerebellar defect associated with Schimke immuno-osseous dysplasia.

UNLABELLED: We report the finding of an absent cerebellar hemisphere and partial absence of the cerebellar vermis in a child with dysmorphic features, spondyloepiphyseal dysplasia, steroid resistant nephrotic syndrome secondary to focal segmental glomerulosclerosis and T-cell lymphopenia (Schimke immuno-osseous dysplasia). These findings have not, to our knowledge, been described before and are likely to represent the consequence of a vascular event either in-utero or in early infancy. CONCLUSION: Cerebral imaging should be performed early in the course of the disease and should be repeated if further neurological events develop.

Cerebellum↗

Mutation of BSND causes Bartter syndrome with sensorineural deafness and kidney failure.

Antenatal Bartter syndrome (aBS) comprises a heterogeneous group of autosomal recessive salt-losing nephropathies. Identification of three genes that code for renal transporters and channels as responsible for aBS has resulted in new insights into renal salt handling, diuretic action and blood-pressure regulation. A gene locus of a fourth variant of aBS called BSND, which in contrast to the other forms is associated with sensorineural deafness (SND) and renal failure, has been mapped to chromosome 1p. We report here the identification by positional cloning, in a region not covered by the human genome sequencing projects, of a new gene, BSND, as the cause of BSND. We examined ten families with BSND and detected seven different mutations in BSND that probably result in loss of function. In accordance with the phenotype, BSND is expressed in the thin limb and the thick ascending limb of the loop of Henle in the kidney and in the dark cells of the inner ear. The gene encodes a hitherto unknown protein with two putative transmembrane alpha-helices and thus might function as a regulator for ion-transport proteins involved in aBS, or else as a new transporter or channel itself.

Animals↗

ARC syndrome: an expanding range of phenotypes.

AIM: To describe the clinical phenotype in infants with ARC syndrome, the association of arthrogryposis, renal tubular acidosis, and cholestasis. METHODS: The medical records for six patients with ARC syndrome were reviewed, presenting over 10 years to three paediatric referral centres. RESULTS: All patients had the typical pattern of arthrogryposis. Renal Fanconi syndrome was present in all but one patient, who presented with nephrogenic diabetes insipidus. Although all patients had severe cholestasis, serum gamma glutamyltransferase values were normal. Many of our patients showed dysmorphic features or ichthyosis. All had recurrent febrile illnesses, diarrhoea, and failed to thrive. Blood films revealed abnormally large platelets. CONCLUSIONS: ARC syndrome exhibits notable clinical variability and may not be as rare as previously thought. The association of Fanconi syndrome, ichthyosis, dysmorphism, jaundice, and diarrhoea has previously been reported as a separate syndrome: our observations indicate that it is part of the ARC spectrum.

Acidosis, Renal Tubular↗

Mitochondrial cytopathy presenting with focal segmental glomerulosclerosis, hypoparathyroidism, sensorineural deafness, and progressive neurological disease.

A 6 year old boy who presented with steroid unresponsive nephrotic syndrome is reported. He was found to have focal segmental glomerulosclerosis and associated hypoparathyroidism and sensorineural deafness. The child progressed to end stage renal failure and was successfully managed by dialysis and cadaveric renal transplantation. He later developed progressive neurological deterioration and mitochondrial myopathy and neuropathy was diagnosed.

Blotting, Southern↗

Microscopic polyarteritis with renal and cerebral involvement.

We report a 15-year-old girl who presented with renal failure requiring dialysis and a diagnosis of p-ANCA-associated vasculitis. She subsequently developed cerebral vasculitis during treatment with oral cyclophosphamide and prednisolone. Treatment with intravenous cyclophosphamide and plasma exchange produced a complete recovery.

Acute Kidney Injury↗

A comparison of the effects of verocytotoxin-1 on primary human renal cell cultures.

Infection with verocytotoxin-producing Escherichia coli causes haemolytic uraemic syndrome (HUS). Verocytotoxin-1 (VT1) is cytopathic to renal microvascular endothelial cells in culture, supporting the hypothesis that the vasculopathy of HUS is caused directly by the toxic action of VT1 on cells. We provide evidence that VT1 inhibits protein synthesis in primary cultures of glomerular epithelial cells (GE), cortical tubular epithelial cells (CTE) and mesangial cells (MC). Using 100 pg/ml of VT1 we saw a decrease in protein synthesis to 14.3+/-1.9% in vero cells (a primate cell line), 1.7+/-0.3% in GE, 0.9+/-0.4% in CTE and 74.8+/-1.3% in MC at 24 h. The human renal epithelial cells are at least as sensitive as vero cells to the protein synthesis inhibitory effects of VT1 if not more so. Cell viability decreased in all cultures as measured by MTT reduction, neutral red incorporation and lactate dehydrogenase release and followed the same pattern of susceptibility as for protein synthesis inhibition. However, unlike vero cells, death occurred without DNA fragmentation. Cell sensitivity was greatest in cells which bound more VT1.

Animals↗

Coexistence of thin membrane and alport nephropathies in families with haematuria.

The finding of familial haematuria without a history of deafness or renal impairment is often assumed to indicate a benign prognosis. However, we describe three families in whom Alport and thin basement membrane nephropathy were separately identified within the same pedigree. Our findings illustrate the importance of fully investigating families with haematuria, even if thin basement nephropathy has been diagnosed in one member.

Basement Membrane↗

A laboratory model of toxin-induced hemolytic uremic syndrome.

BACKGROUND: Verocytotoxin-producing (Shiga-like toxin-producing) Escherichia coli infection is the principal cause of hemolytic uremic syndrome (HUS). The pathogenesis is unclear, and there is a need for animal models. These are impeded by the different distribution of verocytotoxin receptors between species. We have circumvented this restriction using ricin, which gains entry into cells via various galactose receptors. Like verocytotoxin, ricin specifically cleaves a single adenine from ribosomal RNA. METHODS: Rats were given ricin at a dose of 6.7 micrograms/100 g body wt, with or without lipopolysaccharide at 10 micrograms/100 g body wt. Lipopolysaccharide alone or saline were used as controls. Changes in glomerular filtration rate, hematological parameters, histology, and plasma cytokine concentrations were measured. RESULTS: Extensive glomerular thrombosis, pyknotic nuclei, and an infiltration of ED1-positive cells into glomeruli were observed eight hours after an injection of ricin. Other vascular beds were unaffected. Histologic changes were preceded by oliguric renal failure, hemolysis, and thrombocytopenia. Ricin produced a rise in plasma concentrations of monocyte chemotactic protein-1, > tumor necrosis factor-alpha, > interleukin-1 beta, > interleukin-6. Interferon-gamma showed a small increase at the end of the experiment. CONCLUSIONS: Ricin induces glomerular thrombotic microangiopathy, closely resembling that which occurs in verocytotoxin-producing E. coli-induced HUS. As in HUS, high concentrations of proinflammatory cytokines are present, which are probably a result of cytokine superinduction by the toxin.

Animals↗

The impact of renal replacement therapy on toddler time.

The impact of renal replacement therapy on the day-to-day activity of 5 toddlers is presented. For those on hemodialysis, 50% of the waking hours involved activity related to management of the renal failure; the remainder was spent feeding or in normal (play) activity. Peritoneal dialysis demanded only 10% of waking hours for direct renal activity. The data are potentially useful in counseling families when discussing the impact of renal failure and its management on the toddler.

Activities of Daily Living↗