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Biomedical subjects

D Landau

Publications and source records attributed to D Landau.

At least 19 recordsLinked to original sources
PubMed2006

A classification of hemolytic uremic syndrome and thrombotic thrombocytopenic purpura and related disorders.

The diagnostic terms hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are based on historical and overlapping clinical descriptions. Advances in understanding some of the causes of the syndrome now permit many patients to be classified according to etiology. The increased precision of a diagnosis based on causation is important for considering logical approaches to treatment and prognosis. It is also essential for research. We propose a classification that accommodates both a current understanding of causation (level 1) and clinical association in cases for whom cause of disease is unclear (level 2). We tested the classification in a pediatric disease registry of HUS. The revised classification is a stimulus to comprehensive investigation of all cases of HUS and TTP and is expected to increase the proportion of cases in whom a level 1 etiological diagnosis is confirmed.

Animals↗
PubMed2006

Potassium-related inherited tubulopathies.

Hyper- and hypokalemia may carry severe clinical consequences. Different regulatory mechanisms, including the kidney, exert a tight regulation of plasma potassium levels. The renal pathway of potassium handling begins in the proximal tubule followed by the fine-tuning of its secretion or absorption at the distal tubule, including the thick ascending limb of Henle's loop, the distal convoluted tubule and the cortical collecting duct. Genetic studies in recent years have clarified the role of specific tubular channels and transporters in the pathogenesis of unique hyper- and hypokalemic tubulopathies, some of them non-hypertensive (pseudohypoaldosteronism, Bartter and Gitelman syndromes) and others hypertensive by definition (including Liddle and Gordon syndromes). This article reviews the genetic and clinical spectrum of hypokalemic and hyperkalemic tubulopathies.

Animals↗
PubMed2006

Astigmatism after mersilene and nylon suture use for penetrating keratoplasty.

PURPOSE: To evaluate postoperative astigmatism after the use of Mersilene and nylon sutures for penetrating keratoplasty. METHODS: Two groups of 12 patients each (age, 20-50 years) suffering from keratoconus underwent penetrating keratoplasty. Continuous suturing combined with 12 interrupted sutures was used in each case: Mersilene 11-0 sutures were used in group 1, whereas nylon 10-0 sutures were used in group 2. Sutures were removed to control astigmatism when required. All patients were monitored for 36 months. RESULTS: During the follow-up period, sutures were removed in each eye as indicated by astigmatism or breakage. In group 1 (Mersilene 11-0 sutures), no breakage of sutures was recorded. In group 2 (nylon 10-0 sutures), breakage of sutures was recorded in 11 of 12 cases. However, continuous sutures were removed in 2 patients in group 2. After the first year, the astigmatism remained within +/-1.00 diopter in all except 1 patient in group 1 and in 5 patients in group 2. No suture-related complications were recorded except for scarring with photophobia in 1 patient in group 1 and suture breakage in 11 eyes in group 2. CONCLUSION: Mersilene sutures can provide a stable postoperative astigmatism, whereas nylon sutures have a tendency to break and cause changes in corneal astigmatism.

Adult↗
PubMed2006

Intraplacental choriocarcinoma metastasizing to the maternal lung.

BACKGROUND: Although normal pregnancy is the precursor of 25% of cases of maternal choriocarcinoma, intraplacental choriocarcinoma in an otherwise normal placenta associated with viable pregnancy has rarely been reported. CASE: Examination of the placenta after delivery of a pale and small-for-date infant at term revealed intraplacental choriocarcinoma. There was no evidence of metastatic disease in the mother or child, but the mother exhibited postpartum rising levels of beta-HCG. The mother refused chemotherapy and disappeared from follow-up. Nine months later, she presented with metastatic choriocarcinoma of the lung. Eleven courses of the multi-drug EMA CO regimen effected a decrease of beta-HCG to normal and disappearance of lung metastases. To date, 28 months after the end of chemotherapy, the patient is alive and without evidence of gestational trophoblastic disease. Moreover, since then she has given birth to an additional two children. CONCLUSIONS: This case is an example of natural disease progression of intraplacental choriocarcinoma metastasizing to the mother. Furthermore, it supports common knowledge that the multi-drug EMA CO regimen is effective treatment in poor prognosis metastatic choriocarcinoma.

Adult↗
PubMed2005

Facial nerve palsy after acute exposure to dichloromethane.

BACKGROUND: Dichloromethane poisoning affects predominantly the central nervous and the cardiovascular systems, and results from both carboxyhemoglobin formation and direct solvent-related narcosis. Exposure is frequently occupational and related to paint-stripping. Several reports have described severe adverse effects as well as fatalities. Conflicting reports regarding peripheral nerve toxicity have been found with no reports of clinical acute toxicity heretofore. METHODS: We present a case report of a patient who developed a facial nerve palsy after acute occupational exposure to Dichloromethane. The patient was part of a paint removing crew who have worked without proper protecting measures and were thus exposed to high levels of Dichoromethane. RESULTS: The patient was involved in paint stripping with Dichloromethane, and developed facial nerve palsy. Other known causes of facial palsy were excluded, and although idiopathic palsy cannot be ruled out, there were no corroborating findings. Carboxyhemoglobin levels taken after a significant delay were normal. CONCLUSION: This is the first article that describes a case of Facial Nerve Palsy related to acute dichloromethane exposure, indicating a possible peripheral neurotoxic effect of this solvent.

Acute Disease↗
PubMed2004

Sympathetically induced spontaneous fluctuations of the photoplethysmographic signal.

The photoplethysmographic signal shows very low-frequency (VLF) spontaneous fluctuations that have been shown to be mediated by the sympathetic nervous system. In the current study, the photoplethysmographic signal was simultaneously measured in the two index fingers and the two second toes of 54 healthy male subjects. For each photoplethysmographic pulse, two parameters were derived: the pulse amplitude and its baseline, which are related to the arterial wall compliance and to the arterial blood volume, respectively. The baseline and the amplitude VLF fluctuations showed high right-left correlation both for hands (mean +/- SD 0.94 +/- 0.05 and 0.92 +/- 0.07, respectively) and for feet (0.90 +/- 0.08 and 0.89 +/- 0.07, respectively) that only slightly depended on the subject's age. Lower correlation was found between the hand and the foot (0.73 +/- 0.12 and 0.72 +/- 0.12 for the baseline and the amplitude, respectively). For each hand and foot the baseline and the amplitude VLF fluctuations were also correlated, with the baseline fluctuations lagging the amplitude fluctuations by 3-20 pulses. The amplitude-baseline correlation and the standard deviation of the amplitude or the baseline divided by its mean significantly decreased with age. The VLF fluctuations of the photoplethysmographic parameters and the correlation coefficients between them provide better understanding of the autonomic nervous regulation of the blood circulation.

Adult↗
PubMed2004

A novel mutation in the SLC17A5 gene causing both severe and mild phenotypes of free sialic acid storage disease in one inbred Bedouin kindred.

Four members of an extended consanguineous Bedouin family presented with different phenotypic variants of an autosomal recessive lysosomal free sialic acid storage disease. One affected individual had congenital ascites followed by rapid clinical deterioration and death, a presentation concordant with the clinical course of infantile free sialic acid storage disorder. His three first cousins had a more slowly progressive neurodegenerative disease, in line with the clinical phenotype of the milder form (Salla type) of this lysosomal disorder. Diagnosis of free sialic acid storage disease was based on clinical findings, histology, and biochemical assays of sialic acid. Molecular studies showed that all four affected individuals were homozygous for the same novel 983G > A mutation in exon 8 of the SLC17A5 gene, replacing glycine with glutamic acid at position 328 of the sialin protein. This family demonstrates the significant phenotypic variability of the disease in affected members of a single inbred kindred with precisely the same mutation, suggesting a role for modifier genes or environmental factors. It also highlights the need to consider this rare disorder in the differential diagnosis of congenital ascites and of unexplained psychomotor retardation, ataxia, and hypomyelination in infancy.

Adult↗
PubMed2004

Mitomycin C for pterygium: long term evaluation.

AIM: To evaluate long term complications after pterygium excision with mitomycin C (MMC) application. DESIGN: Prospective non-comparative interventional case series. PARTICIPANTS: Ninety nine patients who underwent pterygium surgery and participated in a controlled study for efficacy of MMC for pterygium surgery between 1989 and 1994. METHODS: Patients who were located and agreed to come for examination underwent a complete eye examination. The bare sclera area, in particular, was examined for possible complications. The main outcome measures were anatomical findings in area of MMC application. RESULTS: Forty three eyes of 43 patients were examined. Sixty three per cent of patients had pterygium surgery with intraoperative application of 0.02% MMC for 5 minutes and 37% of patients received MMC 1% or 2% drops four times daily for 2 weeks postoperatively. In three patients, pterygium recurred within 18 months. The only complication was mild conjunctival avascularity in areas of pterygium excision in 30% of patients. CONCLUSION: Long term evaluation revealed that the use of MMC in pterygium surgery is safe, but for a strict selection of patients, controlled use of MMC and long term follow up are required.

Adult↗
PubMed2003

Brachial artery pseudoaneurysm in a premature infant.

A case of brachial artery pseudoaneurysm in a premature infant is reported. The lesion was surgically resected, and arterial continuity restored by end to end anastomosis. The postoperative period and follow up were uneventful.

Aneurysm, False↗
PubMed2002

Involvement of the skeletal GH-IGF system in an experimental model of diabetes-induced growth retardation.

Uncontrolled diabetes is associated with growth retardation. We investigated the effect of insulin-dependent diabetes on animal growth and IGF-I gene expression in the epiphyseal growth plate region of the long bones. We also studied the effect of GH administration on somatic growth in the diabetic state. Streptozotocin (STZ)-injected diabetic rats had a decreased somatic growth rate in comparison to controls. GH administration (2.5 U/kg day) in the diabetic animals (DGH group) prevented this decrease. Serum IGF-I levels were decreased in both diabetic and DGH animals. Within 72 h from diabetes onset, IGF-I mRNA levels in epiphyseal growth plate homogenates decreased whereas IGF-I receptor mRNA levels increased in diabetic animals. The decrease in IGF-I mRNA transcript levels was localized to the metaphyseal region by in situ hybridization. We conclude that in the STZ-induced diabetic state, the reduction in linear growth is associated with a parallel decrease in IGF-I gene expression at the epiphyseal growth plate area. Diabetic growth retardation can be reversed with GH administration, which does not reconstitute serum IGF-I levels. Therefore, we speculate that GH in this model may act locally through the skeletal GH-IGF-I system.

Animals↗
PubMed2001

A recessive contiguous gene deletion of chromosome 2p16 associated with cystinuria and a mitochondrial disease.

Deletions ranging from 100 Kb to 1 Mb--too small to be detected under the microscope--may still involve dozens of genes, thus causing microdeletion syndromes. The vast majority of these syndromes are caused by haploinsufficiency of one or several genes and are transmitted as dominant traits. We identified seven patients originating from an extended family and presenting with a unique syndrome, inherited in a recessive mode, consisting of cystinuria, neonatal seizures, hypotonia, severe somatic and developmental delay, facial dysmorphism, and lactic acidemia. Reduced activity of all the respiratory chain enzymatic complexes that are encoded in the mitochondria was found in muscle biopsy specimens of the patients examined. The molecular basis of this disorder is a homozygous deletion of 179,311 bp on chromosome 2p16, which includes the type I cystinuria gene (SLC3A1), the protein phosphatase 2Cbeta gene (PP2Cbeta), an unidentified gene (KIAA0436), and several expressed sequence tags. The extent of the deletion suggests that this unique syndrome is related to the complete absence of these genes' products, one of which may be essential for the synthesis of mitochondrial encoded proteins.

Abnormalities, Multiple↗
PubMed2001

Clinical and genetic characterization of an autosomal dominant nephropathy.

Autosomal dominant familial nephropathies with adult onset, no macroscopic cysts, and progressive deterioration include medullary cystic disease (ADMCKD) as well as other less specific entities. We studied a kindred of Jewish ancestry in which 15 members (both male and female) have suffered from chronic renal failure. The first evidence of renal involvement was observed between 18 and 38 years. It included hypertension followed by progressive renal insufficiency. No polyuria, anemia, gout, hematuria, nor proteinuria were seen. An average of 4.5 years elapsed from diagnosis to end-stage renal disease. Renal pathology at early stages of the disease showed extensive tubulointerstitial fibrosis and global glomerulosclerosis. Linkage analysis was performed at the two known loci of ADMCKD, on Chromosomes 1 and 16. Linkage to the chromosome 16 locus was excluded. However, linkage to the chromosome 1q21 locus of ADMCKD was established with a maximum two-point LOD score of 3.82 to D1S394. The disease interval could be narrowed to about 9 cM/7.4 Mb between D1S1156 and D1S2635. Multiple-point linkage analysis revealed a maximum LOD of 4.21, with a broad peak from markers D1S2858 and D1S2624. This report establishes linkage between a familial nephropathy characterized by hypertension and progressive renal failure to the locus described for ADMCKD, a disease classically associated with macroscopic corticomedullary cysts, salt-losing tubulointerstitial nephropathy, and anemia. This finding broadens the clinical spectrum of ADMCKD positioned on chromosome 1q21 locus.

Adult↗
PubMed2001

Cardiac avoidance in breast radiotherapy: a comparison of simple shielding techniques with intensity-modulated radiotherapy.

BACKGROUND AND PURPOSE: Adjuvant breast radiotherapy (RT) is now part of the routine care of patients with early breast cancer. However, analysis of the Early Breast Cancer Trialists' Collaborative suggests that patients with the lowest risk of dying of breast cancer are at significant risk of cardiac mortality due to longer relapse-free survival. Patients with a significant amount of heart in the high-dose volume have been shown to be at risk of fatal cardiac events. This study was designed to assess whether conformal planning or intensity-modulated radiotherapy (IMRT) techniques allow reduced cardiac irradiation whilst maintaining full target coverage. MATERIAL AND METHODS: Ten patients with early breast cancer were available for computed tomography (CT) planning. Each had at least 1 cm maximum heart depth within the posterior border of conventional tangents. For each patient, plans were generated and compared using dose volume histograms for planning target volume (PTV) and organs at risk. The plans included conventional tangents with and without shielding. The shielding was designed to either completely spare the heart or to shield as much heart as possible without compromising PTV coverage. IMRT plans were also prepared using two- and four-field tangential and six-field arc-like beam arrangements. RESULTS: PTV homogeneity was better for the tangential IMRT techniques. For all patients, cardiac irradiation was reduced by the addition of partial cardiac shielding to conventional tangents, without compromise of PTV coverage. The two- and four-field IMRT techniques also reduced heart doses. The average percentage volume of heart receiving >60% of the prescription dose was 4.4% (range 1.0-7.1%) for conventional tangents, 1.5% (0.2-3.9%) for partial shielding, 2.3% (0.5-4.6%) for the two-field IMRT technique and 2.2% (0.4-5.6%) for the four-field IMRT technique. For patients with larger maximum heart depths the four-field IMRT plan achieved greater heart sparing than the partial shielding, although irradiation of the contralateral breast was increased. Full cardiac shielding resulted in the most complete heart sparing but with compromise of the PTV coverage; the mean volume receiving less than 95% of the prescription dose was 4% (range 1.5-8.7%). CONCLUSION: All patients undergoing adjuvant tangential breast RT in whom the heart is seen to be in the high-dose volume should be considered for the addition of cardiac-sparing lead blocks. Three-dimensional CT planning and alternative beam arrangements with IMRT optimization enables more complete cardiac sparing without compromise of PTV coverage in certain patients.

Breast Neoplasms↗
PubMed2001

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↗
PubMed2001

Post renal transplantation human herpesvirus 8-associated lymphoproliferative disorder and Kaposi's sarcoma.

Post-transplantation lymphoproliferative disorders (PTLDs) and Kaposi's sarcoma (KS) are immunosuppression-related tumours developing in solid organ transplant patients. Although the Epstein-Barr virus (EBV) is detected in the majority of the PTLDs during the first year after transplantation, the proportion of EBV-negative PTLDs has increased in recent years. We report a case of a 17-year-old man who developed severe immune haemolytic anaemia, KS and human herpesvirus 8 (HHV-8)-associated, polymorphic-type PTLD 9 months after allogeneic renal transplantation from his HHV-8-seropositive father. It is suggested that: (i) HHV-8 may be associated with EBV-negative, polymorphous-type PTLD occurring less than 1 year after transplantation, and (ii) PTLD may be listed among other tumours, including KS, Castleman's disease and primary effusion lymphoma (PEL), that are related to HHV-8 infection.

Adolescent↗
PubMed2001

A novel somatostatin analogue prevents early renal complications in the nonobese diabetic mouse.

BACKGROUND: PTR-3173 (S) is a novel somatostatin analogue that has been found to exert a prolonged inhibitory action on the growth hormone (GH)-insulin-like growth factor (IGF)-I axis, but not on insulin secretion. We investigated the potential effect of this agent on the development of markers of diabetic nephropathy in the nonobese diabetic (NOD) mouse model of insulin-dependent diabetes. METHODS: Female diabetic NOD mice treated with PTR-3173 (DS group) or saline (D) and their control groups of nonhyperglycemic age-matched littermates (C) and C mice treated with PTR-3173 (CS) were sacrificed three weeks after onset of diabetes. RESULTS: Serum GH was elevated in the D group, decreased in the DS group, and unchanged in the CS group. Serum IGF-I was significantly decreased in both the D and DS groups. Kidney weight, glomerular volume, albuminuria, and creatinine clearance were increased in the D animals and showed a trend toward normalization in the DS animals. Renal extractable IGF-I protein and IGFBP1 mRNA were increased in the D group and normalized in the DS group. CONCLUSIONS: GH antagonism by PTR-3173 has a blunting effect on renal/glomerular hypertrophy, albuminuria, and glomerular filtration rate (GFR) in diabetic NOD mice. This phenomenon is apparently associated with the prevention of renal IGF-I accumulation. Thus, modulation of GH effects may have beneficial therapeutic implications in diabetic nephropathy.

Albuminuria↗
PubMed2001

Familial hemolytic uremic syndrome associated with complement factor H deficiency.

Atypical hemolytic uremic syndrome (HUS) associated with factor H deficiency (FHD) carries a poor prognosis. A 3-year-old girl with FHD-HUS reached end-stage renal disease at age 6 months after experiencing numerous relapses; she underwent a cadaveric renal transplant at age 46 months. One month after transplantation, she experienced an extensive non-hemorrhagic cerebral infarction. Later, hematologic and renal manifestations of HUS developed, followed by another massive cerebral infarction and death in spite of multiple plasma transfusions. A 14-month-old boy with FHD-HUS experienced numerous HUS episodes starting at the age of 2 weeks. Daily plasma transfusions during relapses brought about only a temporary state of remission. However, prophylactic twice-weekly plasma therapy has been successful in preventing relapses and preserving renal function. With this regimen, serum factor H was increased from 6 mg/dL to subnormal values of 12 to 25 mg/dL (normal >60 mg/dL). We conclude that FHD-HUS recurs because FHD is not corrected by renal transplantation. A hypertransfusion protocol may prevent FHD-HUS.

Blood Transfusion↗