Biomedical subjects

J Kaplan

Publications and source records attributed to J Kaplan.

At least 91 records · Page 5Linked to original sources

PubMed1999

Similar embryotoxic effects of sera from infertile patients and exogenous interferon-gamma on long-term in-vitro development of mouse embryos.

Circulating embryotoxic factors could be responsible for reproductive failures observed in patients suffering from recurrent spontaneous abortions (RSA) and endometriosis. The mouse bioassay has been widely used to detect such factors, since sera from these patients inhibit early embryonic development. This bioassay consists in the in-vitro culture of two-cell mouse embryos in the presence of different sera up to the blastocyst stage (72 h of culture). In the present study experiments were performed over long culture times (3-7 days), from two-cell to spreading stages, to determine the in-vitro effect of sera obtained from RSA or endometriosis patients, as well as the effect of interferon (INF)-gamma on embryo development. An embryotoxicity cut-off value of 45% blastocyst formation was established using control sera. When development to the blastocyst stage was considered only 25% of RSA and 20% of endometriosis sera were embryotoxic. However, all RSA sera significantly inhibited hatching (P < 0.05) and spreading stages (P < 0.01). IFN-gamma (10 micrograms/ml) (P < 0.001) did not impair early embryo development, but significantly inhibited blastocyst spreading. These observations suggest that culture to advanced embryonic stages increases the sensitivity of the bioassay and that IFN-gamma alters in-vitro peri-implantation mouse embryo development.

Abortion, Spontaneous↗

PubMed1999

Measurement of serum bone-specific alkaline phosphatase activity in cynomolgus macaques.

Serum levels of bone-specific alkaline phosphatase activity (B-ALP) in cynomolgus monkeys were evaluated as an index of elevated bone turnover following ovariectomy. The enzyme immunoassay 96-well microtiter plate B-ALP assay, developed by Metra Biosystems (Mountain View, CA) for human use, was employed and compared with a standard automated assay measuring total serum levels of alkaline phosphatase activity (T-ALP). The B-ALP assay was first validated for use in these monkeys. Ovariectomy led to increased bone turnover as indicated by approximately 2-fold higher activity in both assays and this elevation was inhibited by daily estradiol administration. Although both assays provided generally similar results, several monkeys were observed to have greatly elevated values of T-ALP but not B-ALP. This discrepancy is believed to result from high levels of the liver isoform of alkaline phosphatase in monkeys with hepatic dysfunction, which are not detected by the B-ALP assay.

Alkaline Phosphatase↗

PubMed1999

Transcutaneous glucose measurement using near-infrared spectroscopy during hypoglycemia.

OBJECTIVE: To analyze a transcutaneous near-infrared spectroscopy system as a technique for in vivo noninvasive blood glucose monitoring during euglycemia and hypoglycemia. RESEARCH DESIGN AND METHODS: Ten nondiabetic subjects and two patients with type 1 diabetes were examined in a total of 27 studies. In each study, the subject's plasma glucose was lowered to a hypoglycemia level (approximately 55 mg/dl) followed by recovery to a glycemic level of approximately 115 mg/dl using an intravenous infusion of insulin and 20% dextrose. Plasma glucose levels were determined at 5-min intervals by standard glucose oxidase method and simultaneously by a near-infrared spectroscopic system. The plasma glucose measured by the standard method was used to create a calibration model that could predict glucose levels from the near-infrared spectral data. The two data sets were correlated during the decline and recovery in plasma glucose, within 10 mg/dl plasma glucose ranges, and were examined using the Clarke Error Grid Analysis. RESULTS: Two sets of 1,704 plasma glucose determinations were examined. The near-infrared predictions during the fall and recovery in plasma glucose were highly correlated (r = 0.96 and 0.95, respectively). When analyzed during 10 mg/dl plasma glucose segments, the mean absolute difference between the near-infrared spectroscopy method and the chemometric reference ranged from 3.3 to 4.4 mg/dl in the nondiabetic subjects and from 2.6 to 3.8 mg/dl in the patients with type 1 diabetes. Using the Error Grid Analysis, 97.7% of all the near-infrared predictions were assigned to the A-zone. CONCLUSIONS: Our findings suggest that the near-infrared spectroscopy method can accurately predict plasma glucose levels during euglycemia and hypoglycemia in humans.

Adult↗

PubMed1999

Vertebral Aspergillus osteomyelitis and acute diskitis in patients with chronic obstructive pulmonary disease.

Aspergillus osteomyelitis of the spine with acute diskitis has been well documented in immunocompromised hosts but is rare in immunocompetent patients. Predisposing factors to infection are prolonged neutropenia, hematologic malignancies, chemotherapy, history of prior spinal trauma or surgery, allograft transplantation, or any condition requiring the use of long-term immunosuppressive agents or systemic corticosteroids. Patients with chronic obstructive pulmonary disease (COPD) treated with systemic corticosteroids for either long-term management or frequent exacerbations are at potential risk for such infections. Patients with severe COPD treated primarily with inhaled corticosteroids are considered immunocompetent. This report describes 2 cases of Aspergillus osteomyelitis with acute diskitis in apparently immunocompetent patients with COPD who, aside from brief courses of systemic corticosteroids, were using inhaled corticosteroid therapy. One patient was treated with intravenous amphotericin B alone, whereas the other received amphotericin B and underwent surgical debridement. Both have done well and were symptom free at 6-month follow-up.

Acute Disease↗

PubMed1999

A novel ABCR nonsense mutation responsible for late-onset fundus flavimaculatus.

PURPOSE: To report the ophthalmologic features of a novel truncating mutation in the ABCR gene in a patient affected with late-onset fundus flavimaculatus (FFM). METHODS: A complete ophthalmologic examination was performed in a 70-year-old patient, including best-corrected visual acuity measurement, slit lamp and fundus examination, fundus photographs, frequent fluorescein and indocyanine green angiographies, visual field testing, color vision analysis, electroretinogram, and electro-oculogram. The 50 exons of the ABCR gene were analyzed using direct sequencing. RESULTS: Fluorescein and indocyanine green angiographies confirmed the diagnosis of FFM. A heterozygous base change was found, resulting in the substitution of an arginine to a stop at codon 152 of the ABCR gene. CONCLUSIONS: A heterozygous nonsense ABCR gene mutation was found in a patient affected with FFM. No other mutation has been identified in the entire coding sequence and the promoter region, suggesting that a heterozygous severe ABCR mutant may be responsible for a mild and delayed FFM phenotype, different from that of age-related macular degeneration.

ATP-Binding Cassette Transporters↗

PubMed1999

Mutations of the retinal specific ATP binding transporter gene (ABCR) in a single family segregating both autosomal recessive retinitis pigmentosa RP19 and Stargardt disease: evidence of clinical heterogeneity at this locus.

Stargardt disease (STGD) is an autosomal recessive macular dystrophy of childhood characterised by bilateral loss of central vision over a period of several months. STGD has been mapped to chromosome 1p22.1 and recently ascribed to mutations in the retinal specific ATP binding transporter gene (ABCR). The fundus flavimaculatus with macular dystrophy (FFM), an autosomal recessive condition responsible for gradual loss of visual acuity in adulthood (second to third decade) has also been mapped to the same locus. However, a gene for autosomal recessive retinitis pigmentosa with distinctive features of choriocapillaris atrophy at an advanced stage (RP19) has been mapped to the genetic interval encompassing the STGD gene on chromosome 1p (D1S435-D1S236), raising the question of whether, despite striking differences in clinical course and presentation, RP19 and STGD might be allelic disorders at the ABCR locus. In a family segregating RP and STGD in two first cousins, we found that heterozygosity for a splicing mutation in the ABCR gene (1938-1 G-->A) resulted in STGD while hemizygosity for this splice mutation resulted in RP, and when studying the RP patient's parents, we found a maternal non-contribution with apparent segregation of a null allele ascribed to a partial deletion of the ABCR gene. The present study shows that, despite striking clinical differences, RP19 and STGD are allelic disorders at the ABCR locus.

ATP-Binding Cassette Transporters↗

PubMed1999

[Endoscopic visualization of BAR (biofragmentable anastomotic ring)].

The authors present information on the use of a modern sutureless anastomotic connection by means of a biofragmentable ring--BAR (Biofragmentable Anastomotic Ring) which was used in patients to restore the continuity of the GIT after resections in the upper portions of the digestive tract. The authors present their initial clinical experience and emphasize the importance of visualization of biofragmentable anastomoses by gastroscopic examination in case of postoperative complications with the possibility of therapeutic provisions, if necessary.

Adult↗

PubMed1998

Iron in cytosolic ferritin can be recycled through lysosomal degradation in human fibroblasts.

Examination of the mechanism of intracellular iron recovery from lysosomally-degraded ferritin in vivo has been complicated by the continuous flux of cellular iron through ferritin molecules. Here we incubated human fibroblasts with cationic ferritin, a derivative of horse spleen ferritin, as a technique for delivering immunologically distinct ferritin molecules directly to lysosomes. Using this method, we found increased endogenous ferritin levels after the cellular degradation of cationic ferritin, demonstrating that cells can utilize lysosomal ferritin to produce increased cytosolic ferritin levels. Further, using an in vitro assay, we showed that isolated lysosomes degrade endogenous ferritin in a time- and temperature-dependent manner. These results are consistent with a model in which cytosolic ferritin is taken into the lysosomes and degraded. The solubilized iron from the ferric core could then be transported across the lysosomal membrane back into the cytosol.

Cells, Cultured↗

PubMed1998

Chloride is an allosteric effector of copper assembly for the yeast multicopper oxidase Fet3p: an unexpected role for intracellular chloride channels.

GEF1 is a gene in Saccharomyces cerevisiae, which encodes a putative voltage-regulated chloride channel. gef1 mutants have a defect in the high-affinity iron transport system, which relies on the cell surface multicopper oxidase Fet3p. The defect is due to an inability to transfer Cu+ to apoFet3p within the secretory apparatus. We demonstrate that the insertion of Cu into apoFet3p is dependent on the presence of Cl-. Cu-loading of apoFet3p is favored at acidic pH, but in the absence of Cl- there is very little Cu-loading at any pH. Cl- has a positive allosteric effect on Cu-loading of apoFet3p. Kinetic studies suggest that Cl- may also bind to Fet3p and that Cu+ has an allosteric effect on the binding of Cl- to the enzyme. Thus, Cl- may be required for the metal loading of proteins within the secretory apparatus. These results may have implications in mammalian physiology, as mutations in human intracellular chloride channels result in disease.

Allosteric Regulation↗

PubMed1998

Defects in the yeast high affinity iron transport system result in increased metal sensitivity because of the increased expression of transporters with a broad transition metal specificity.

Yeast with defects in vacuolar pH show increased sensitivity to high concentrations of transition metals. This sensitivity has been presumed to result from defective metal storage. We demonstrate that mutations that result in a defective high affinity iron transport system, such as a deletion in the surface ferroxidase FET3, also result in increased metal sensitivity independent of vacuolar function. Multiple copies of transition metal transporter resistance genes, such as COT1 or ZRC1, do not reduce the metal sensitivity of fet3 mutations. Increased metal sensitivity is because of an increased cellular accumulation of transition metals resulting from the increased activity of low affinity iron transporters, such as FET4, that mediates the transport of other transition metals. In cells lacking a high affinity iron transport system, the increased transition metal uptake can be prevented by increased extracellular iron. These results suggest that vacuolar function may not be required for transition metal sequestration.

Base Sequence↗

PubMed1998

Site-directed mutagenesis of the yeast multicopper oxidase Fet3p.

High affinity iron transport in yeast is mediated by two proteins, Fet3p and Ftr1p. The multicopper oxidase Fet3p is thought to convert extracellular ferrous iron to ferric iron, which then crosses the plasma membrane through the permease Ftr1p. Fet3p is capable of oxidizing other substrates, such as p-phenylenediamine, and there is still a question of whether it is the ferroxidase activity that is essential for iron transport. Fet3p is also required for Ftr1p localization to the cell surface, making it difficult to prove a direct role for Fet3p oxidase in high affinity iron transport. In an attempt to generate Fet3p specifically lacking ferroxidase activity, we used site-directed mutagenesis to alter residues within Fet3p that had been suggested to impart iron oxidase activity. These substitutions resulted in either a loss or retention of both p-phenylenediamine and ferroxidase activities, indicating that the ability of Fet3p to act as a ferroxidase involves other amino acids. Inactive Fet3p, however, did mediate Ftr1p localization to the cell surface but did not mediate high affinity iron transport. These observations indicate that the ferroxidase activity of Fet3p is intrinsically required for high affinity iron transport.

Amino Acid Sequence↗

PubMed1998

Complete exon-intron structure of the retina-specific ATP binding transporter gene (ABCR) allows the identification of novel mutations underlying Stargardt disease.

Stargardt disease, an autosomal recessive macular dystrophy of childhood, leading to severe visual impairment, is caused by mutations in the retina-specific ATP binding transporter gene (ABCR). Previously, the ABCR cDNA and part of the exon-intron structure were described. We have determined the complete ABCR exon-intron structure by exon-exon PCR. The ABCR gene encompasses 50 exons, 29 of which are first described here with their corresponding intron-exon boundaries. The discovery of a splicing mutation (571: 2A-->G) and missense mutations in the newly identified exons (R18W, R212C) gives additional support to the broad allelic heterogeneity of Stargardt disease.

ATP-Binding Cassette Transporters↗

PubMed1998

Exclusion of five subunits of cGMP phosphodiesterase in Leber's congenital amaurosis.

Leber's congenital amaurosis (LCA) is the earliest and most severe of all inherited retinal dystrophies. Recently, we mapped an LCA gene to chromosome 17p13.1 (LCA1) and ascribed the disease to mutations of the retinal guanylate cyclase (ret GC) gene in a subset of families of North African ancestry. Owing to the genetic heterogeneity of LCA and considering that LCA1 results from an impaired production of cGMP in the retina (with permanent closure of cGMP-gated cation channels), we hypothesized that the activation of the cGMP phosphodiesterase (PDE) could trigger the disease by lowering the intracellular cGMP level in the retina. The rod and cone cGMP-PDE inhibitory subunits were regarded therefore as candidate genes in LCA. Here, we report the exclusion of five rod and cone cGMP-PDE subunits in LCA families unlinked to chromosome 17p13.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1998

Lack of association between apolipoprotein E genotype and sporadic amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neuro-degenerative disorder with both sporadic and familial forms. Approximately 20% of autosomal dominant ALS is caused by mutations in the Cu/Zn superoxide dismutase (SOD1) gene. The causes of the remaining forms of ALS are unknown. The apolipoprotein E (APOE) gene is a known genetic risk factor for Alzheimer disease (AD), another neuro-degenerative disease. The APOE-4 allele increases risk and decreases age at onset in AD. Studies examining ALS and APOE have failed to show a significant effect of APOE on overall risk in ALS. Studies examining the effect of APOE-4 on site of onset in ALS (bulbar or limb) have been contradictory, with some studies showing an APOE association with bulbar onset and others showing no effect. Sample size was limited in these previous reports, particularly with respect to the number of bulbar onset cases (n = 33, 34 and 53). The present study examines a large collaborative data set of ALS patients (n = 363; 95 with bulbar onset) and age-matched neurologically normal controls. The results for these data showed no significant differences in the percentage of subjects with the APOE-4/4 and APOE-4/X genotypes (X = APOE-2 or APOE-3) when comparing cases and controls in both the overall data set or in the data set stratified by site of onset. Similarly, logistic regression analysis in the overall and stratified data set while controlling for sex showed no increase or decrease in risk of ALS associated with the APOE-4 allele. In addition, there were no significant differences in age at onset between patients with APOE-X/X, and APOE-4/4 or APOE-4/X genotypes, overall or stratified by site of onset. We conclude based on these data that the APOE gene is not a major genetic risk factor for site of onset in ALS.

Adult↗

PubMed1998

The epsilon4 allele of the apolipoprotein E gene as a potential protective factor for exudative age-related macular degeneration.

PURPOSE: Apolipoprotein E (ApoE) is a polymorphic protein that plays a central part in plasma metabolism of lipids and in central nervous system lipid homeostasis. Our purpose was to evaluate the potential role of ApoE polymorphism in the occurrence of exudative age-related macular degeneration associated with drusen, which contain lipids. METHODS: We analyzed apolipoprotein E genotypes in 116 unrelated patients with exudative age-related macular degeneration in one eye and hard drusen (n = 39) or soft drusen (n = 77) in the other eye, and compared the results with those of age-matched and sex-matched control subjects (n = 168). Apolipoprotein E alleles were detected by a ploymerase chain reaction-based method. RESULTS: A lower frequency of the epsilon4 allele carriers was observed in the exudative age-related macular degeneration group compared with control subjects (12.1% vs 28.6%, respectively; P < .0009). The epsilon4 allele was less frequent in the age-related macular degeneration group compared with control subjects (0.073 vs 0.149, respectively; P < .006). This decreased frequency of the epsilon4 allele was mainly observed in the soft drusen subgroup compared with control subjects (0.045 vs 0.149, respectively; P < .0009). CONCLUSION: This lower relative frequency of the epsilon4 allele supports the hypothesis that the ApoE gene is a genetic protective factor identified in age-related macular degeneration.

Aged↗

PubMed1998

Macular dystrophy, diabetes, and deafness associated with a large mitochondrial DNA deletion.

PURPOSE: To report the mitochondrial DNA in a 17-year-old patient with diabetes, deafness, cataract, and maculopathy. METHOD S: Ophthalmologic examination, fluorescein angiography, and electroretinogram were performed. Detection of deletion was analyzed by polymerase chain reaction and Southern blot, and screening for the A3243G mitochondrial DNA mutation was performed. RESULTS: A short fragment of approximately 8.5 kb corresponding to deleted mitochondrial DNA was detected. The A3243G mitochondrial DNA mutation was not found. CONCLUSIONS: A 7-kb heteroplasmic deletion of the mitochondrial genome was found in this patient. No mitochondrial DNA deletion has been reported previously in association with macular dystrophy.

Adolescent↗

PubMed1998

Randomized trial comparing packed red cell blood transfusion with and without leukocyte depletion for gastrointestinal surgery.

BACKGROUND: Allogeneic transfusion is associated with postoperative infections that significantly prolong hospital stays and increase costs. Recent studies suggest that filtering leukocytes from blood prior to transfusion reduces the risk of postoperative infection associated with blood transfusion. We compared the incidence of postoperative infections, hospital stays, and hospital charges of gastrointestinal surgery patients transfused with packed red cells or leukocyte-depleted cells. METHODS: Consecutive patients admitted for elective gastrointestinal surgery without previous blood transfusion were randomized to receive routine packed red cells or packed red cells filtered to remove leukocytes if transfusion was required. Multivariate analysis was used to assess the significance of the relationship between leukocyte-depleted blood and postoperative infectious complications, postoperative stay, and hospital charges. RESULTS: Fifty-nine (27%) of the 221 patients were transfused. The most significant variable related to transfusion was intraoperative blood loss (P <0.0001), followed by admission hematocrit (P <0.0001) and age (P = 0.0022). Infections were noted in 16% of the patients: 11% of untransfused patients, 16% of leukocyte-depleted blood recipients, and 44% of patients transfused with packed red cells. Both operative site and nosocomial infections were significantly (P <0.001) more frequent in patients transfused with packed red cells compared with patients transfused with leukocyte-depleted red cells. Postoperative stays averaged 9 days for untransfused patients, 12 days for leukocyte-depleted recipients, and 18 days for recipients of packed red cells. Hospital charges were $19,132, $33,954, and $41,002, respectively. Both transfusion and infection were significantly (P <0.001) related to postoperative stay in multivariate analysis. Hospital charges were significantly related to postoperative stay (P <0.001), blood loss (P <0.001), age (P <0.001), infection (P = 0.007), and randomization to packed red cells (P = 0.032). CONCLUSIONS: Filtering blood of leukocytes prior to transfusion for elective gastrointestinal surgery is associated with lower risk of postoperative infection, shorter postoperative stays, and lower hospital charges.

Cost-Benefit Analysis↗

PubMed1998

Endothelial injury and leukocyte adherence in Häutchen preparations from coronary arteries and aorta of cynomolgus monkeys.

The aim was to describe the production of en face preparations (Häutchens) of the endothelium from the aorta and the coronary arteries of cynomolgus monkeys (Macaca fascicularis), to describe the morphology of the endothelium and to estimate endothelial injury. The present study describes, for the first time, the application of this technique to the coronary arteries. Numerous leukocytes (peroxidase-positive and -negative cells) were observed on the endothelium and a positive correlation between the numbers of adherent leukocytes and injured endothelial cells was found. A relatively leukocyte-independent measure of endothelial injury in the aorta was obtained by counting areas with a restricted number of leukocytes. The results indicated an even distribution and a relatively low frequency of injured endothelial cells along the arterial tree. The percentage of injured endothelial cells in LAD and LCX was 0.18 and 0.16, and in non-branched and circumostial areas of the descending thoracic aorta the corresponding figures were 0.22 and 0.28. There were, on average, 344 and 236 adherent leukocytes/mm2 in the non-branched and circumostial areas of the descending thoracic aorta, respectively, compared to 13 in the LAD and 23 in the LCX. Proportionally more peroxidase-positive leukocytes (possibly granulocytes) were found on the coronary endothelium than on the aortic endothelium, and the peroxidase-positive cells were preferentially located around small artery branches in the coronary arteries. The foregoing data provide an estimate of the distribution and frequency of endothelial injury and adherent leukocytes at pathobiologically relevant arterial sites in unmanipulated cynomolgus monkeys, an animal frequently used in atherosclerosis research.

Animals↗