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Biomedical subjects

J Adler

Publications and source records attributed to J Adler.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Assisted hatching--a useful micromanipulation technic in women after repeated failure of embryo transfer].

One reason for the low implantation rate after IVF/ET is the limiting ability of blastocysts to escape from the zona pellucida, and of nidation. This procedure can be assisted by the creation of an artificial opening in the zona pellucida before the transfer (assisted hatching). An artificial slot in the zona of 58 embryos (20 patients) was created mechanically by using Leitz Fluovert microscope and Narishige micromanipulators. From 20 embryo transfers 6 clinical pregnancies resulted (30.0% clin. preg. rate). In 4 cases women with three or more unsuccessful transfers were involved. This method should be used in classical IVF, specially in cases of repeated high quality embryo transfers which failed.

Embryo Transfer↗
PubMed1996

[Prolonged culture of human embryos: comparison of coculture on human tubal epithelium and culture in synthetic media].

UNLABELLED: The aim of this work was to evaluate prolongation of cultivation time of human embryos. The prolongation above the standard limit was implemented (1) by coculture of embryos on a monolayer of human epithelial cells and (2) by using a synthetic medium. MATERIAL AND METHODS: Ovarian stimulation, oocyte recovery, insemination and cultivation up to the pronuclear stage were done in our centre in the usual way. Group I: 104 women, prolonged culture by the coculture method. The zygotes were placed on the monolayer and cultivated for an other 24 or 48 hours. Group II: 249 women, prolonged culture in a synthetic medium. The zygotes were cultivated up to the 2- to 4-cell stage in standard IVF medium, and then put into M3 medium for the next 24 or 48 hours. A transfer of a maximum of 4 embryos was done. RESULTS: In group I in 104 women from 341 zygotes 181 embryos (53.1%) reached the eight- and more than eight-cell stage, and 76 transfers were done. 15 pregnancies were achieved (19.4% pregnancy rate). In group II in 249 patients from 672 embryos 49.7% of them reached 8- and more than 8-cell stage. 51 pregnancies were achieved (22.6 pregnancy rate). In the control group of 250 IVF after 48 hours cultivation 165 transfers (66.0%) were done, and 16.4% pregnancies were achieved, i.e. 6.2% less compared to synthetic medium and 3.3% less than in cocultivation. CONCLUSION: There is evidence of better IVF/ET results in case of prolonged culture time. The experience in our centre has shown the need of reevaluation of the coculture method. The exacting character of its preparation and manipulation will have to be replaced by synthetic media in spite of their high price.

Cells, Cultured↗
PubMed1995

Cytoplasmic free-Ca2+ level rises with repellents and falls with attractants in Escherichia coli chemotaxis.

Cytoplasmic free-Ca2+ levels in Escherichia coli were measured by use of the fluorescent Ca(2+)-indicator dye fura-2. Chemotactically wild-type E. coli regulated cytoplasmic free Ca2+ at approximately 100 nM when no stimuli were encountered, but changes in bacterial behavior correlated with changes in cytoplasmic free-Ca2+ concentration. For chemotactically wild-type E. coli, addition of a repellent resulted in cells tumbling and a transient increase in cytoplasmic free-Ca2+ levels. Conversely, addition of an attractant to wild-type cells caused running and produced a transient decrease in cytoplasmic free-Ca2+ levels. Studies with mutant strains showed that the chemoreceptors were required for the observed changes in cytoplasmic free-Ca2+ levels in response to chemical stimuli.

Amino Acids↗
PubMed1995

Phototaxis away from blue light by an Escherichia coli mutant accumulating protoporphyrin IX.

The hemH gene of Escherichia coli encodes ferrochelatase (EC 4.99.1.1), the enzyme that catalyzes the last step in the production of heme, namely the synthesis of heme from protoporphyrin IX plus Fe2+. The behavioral responses to light were studied in E. coli carrying a hemH mutation. It was shown that the hemH mutant displayed a tumbling response upon illumination and a running response upon removal of the light. The most effect light to induce a tumbling response in the hemH mutant was blue light (396-450 nm). The chemotaxis machinery was needed for the light-induced tumbling response in the hemH mutant. The bacterial defect is an analog of the human inherited disease erythropoietic protoporphyria.

Anaerobiosis↗
PubMed1995

A versatile system for multimodality image fusion.

This paper presents a versatile system for registering and visualizing computed tomography and magnetic resonance images. The system utilizes a semi-automatic, surface-based registration strategy which has proven useful for registering a number of different anatomical structures. A triangular mesh approximates surfaces in one image set while a set of surface points is used as a surface approximation in the other set. A non-linear optimization procedure determines the transformation that minimizes the total sum-squared perpendicular distance between triangles of the mesh and surface points. This system has been used without modification to successfully register images of the brain, spine and calcaneus.

Brain↗
PubMed1995

Characterization of mechanosensitive channels in Escherichia coli cytoplasmic membrane by whole-cell patch clamp recording.

Whole-cell patch clamp recordings were done on giant protoplasts of Escherichia coli. The pressure sensitivity of the protoplasts was studied. Two different unit conductance mechanosensitive channels, 1100 +/- 25 pS and 350 +/- 14 pS in 400 mM symmetric KCl solution, were observed upon either applying positive pressure to the interior of the cells or down shocking the cells osmotically. The 1100 pS conductance channel discriminated poorly among the monovalent ions tested and it was permeable to Ca2+ and glutamate-. Both of the two channels were sensitive to the osmotic gradient across the membrane; the unit conductances of the channels remained constant while the mean current of the cell was increased by increasing the osmotic gradient. Both of the channels were voltage sensitive. Voltage-ramp results showed that the pressure sensitivity of protoplasts was voltage dependent: there were more channels active upon depolarization than hyperpolarization. The mechanosensitive channels were reversibly blocked by gadolinium ion. Also they could reversibly be inhibited by protons. Mutations in two of the potassium efflux systems, KefB and KefC, did not affect the channel activity, while a null mutation in the gene for KefA changed the channel activity significantly. This indicates a potential modulation of these channels by KefA.

Antiporters↗
PubMed1995

Analogue of aspartate and glutamate active at synapses are attractants for Escherichia coli.

1. This research was carried out to compare Escherichia coli bacteria with animals in their response to L-aspartate and L-glutamate and their analogues. 2. Various analogues of aspartate and glutamate known to be neurotransmitters at synapses were shown to be attractants for E. coli. 3. The amino acid sequences of the animal receptors and the bacterial receptor, however, have no detectable relationship. Based on the amino acid sequence, evolutionarily the two systems appear not to be related.

Animals↗
PubMed1995

Measurement of nasal mucociliary transport rates on the isolated human inferior turbinate.

The mucociliary transport rate was measured using sequential images of graphite particles moving on 17 isolated human inferior turbinates. These had been removed from 13 patients who had normal saccharin clearance tests on the day of surgery. The initial mean mucociliary transport rate was found to be 4.1 mm/min rising to 5.0 mm/min 2 h after harvesting. After 4 h it fell to 3.7 mm/min. Where the rate was measured at two different sites on the same turbinate (n = 4), there was a close correlation over 6 h (r = 0.95, P < 0.001). When the turbinates were exposed to an aqueous solution of adrenaline (1:10,000) or a 2.5% cocaine solution, the rate increased or decreased respectively by 100% and 58% but returned to within 10% of the initial level within 2 h. We believe that the isolated inferior turbinate can be considered a useful model for the study of mucociliary clearance and agents that may influence it.

Cocaine↗
PubMed1995

Chemotactic properties of Escherichia coli mutants having abnormal Ca2+ content.

The calA, calC, and calD mutants of Escherichia coli are known to be sensitive to Ca2+ (R. N. Brey and B. P. Rosen, J. Bacteriol. 139:824-834, 1979). In the absence of any added stimuli for chemotaxis, both the calC and the calD mutants swam with a tumbly bias. Both the calC and the calD mutants were defective in chemotaxis as measured by computer analysis, use of swarm plates, and capillary assays. The calA mutant was only slightly defective in motility and only slightly impaired in chemotaxis. Chemotactically wild-type cells had an intra-cellular free-Ca2+ level of about 105 nM. The intracellular free-Ca2+ levels of the mutants, as determined by use of the fluorescent Ca2+ indicator dye fura-2 or fluo-3, were about 90, about 1,130, and about 410 nM for calA, calC, and calD, respectively. Lowering the intracellular free-Ca2+ levels in wild-type cells and in the tumbly cal mutants by use of Ca2+ chelators promoted running (smooth swimming). Overexpression of CheZ (which causes dephosphorylation of CheY-phosphate) in the wild type and in the tumbly cal mutants decreased the level of tumbliness (which is caused by CheY-phosphate). The calA mutant was 4- to 10-fold more resistant than the wild type to the inhibitory effect of omega-conotoxin on chemotaxis. omega-Conotoxin had no effect on Ca2+ extrusion by wild-type E. coli; that result suggests that omega-conotoxin affects Ca2+ transport at the point of entry instead of exit.

Calcium↗
PubMed1995

Cultured epidermal allografts for the treatment of deep dermal burns.

The paper summarizes the experience with the application of cultured epidermal allografts in the treatment of deep dermal burns. In a series of patients, including 10 adults and 32 children this method allowed to attain an epithelialization in 90% of deep dermal burns. The advantages of this therapeutic method consist particularly in the early epithelialization of the burnt area and the maintenance of all vital layers of the corium. The risk of a transmission of infection by the transplantation of allografts of live human cells can be minimalized by keeping all directions prescribed for the examination of donors. The possibility of cryopreservation and the easy transport of cultured epidermal allografts renders them available for the use as a new therapeutic method in the treatment of deep dermal burns.

Adult↗
PubMed1994

Quantifying MRI geometric distortion in tissue.

We present a method to quantify the MR field inhomogeneity geometric distortion to subpixel accuracy without using objects of known dimensions and without using an external standard such as CT. Our method may be used to quantify the geometric accuracy of MR images of anatomical structures of unknown geometry and also to test any geometry correction scheme. We have quantified the distortion in a tissue phantom and found the largest error to be approximately 2.8 pixels (1.8 mm) for Bo = 1.5 T, G = 3.13 mT/m and FOV = 160 x 160 x 70.7 mm3. We also found that our previously published correction technique reduced the largest error to 0.3 pixels (mu = 0.02 and sigma = 0.07 pixels).

Image Processing, Computer-Assisted↗
PubMed1994

In vivo visualization of myelin water in brain by magnetic resonance.

We exploit the intrinsic difference in magnetic resonance spin-spin relaxation time, T2, between water associated with myelin sheaths and water in other central nervous system tissue in order to measure myelin water content within any region of an image or to generate indirectly a myelin map of the brain. In normal volunteers, myelin water maps give the expected myelin distribution. In multiple sclerosis patients, lesions exhibit different myelin water contents providing insight into the demyelination process unavailable from conventional magnetic resonance images. In vivo myelin measurement has important applications in the clinical management of multiple sclerosis and other white matter diseases.

Body Water↗
PubMed1994

HIV-1 seroprevalence in chest clinic and hospital tuberculosis patients in New York City, 1989-1991.

OBJECTIVE: To describe more fully HIV-1 and tuberculosis (TB) coinfection in TB patients attending New York City Department of Health chest clinics (1989-1991) and one inner-city hospital (1990-1991). DESIGN: An unlinked serosurvey using HIV-1-antibody testing of remnant blood specimens collected for routine medical purposes. SUBJECTS: A total of 1414 clinic and 856 hospital patients. OUTCOME MEASURES: HIV seropositivity and TB infection/disease. RESULTS: A total of 327 (23%) of the clinic patients were HIV-1-positive, with a significantly higher seroprevalence in men (29 versus 15%, P < 0.001) and in young and middle-aged adults aged 30-50 years (P < 0.001). HIV-1 prevalence by TB diagnostic class was: class 2 (purified protein derivative-positive and chest radiograph-negative), 11% (64 out of 570); class 3 (active disease), 34% (197 out of 582); class IV (old/inactive disease), 30% (39 out of 130). Of the hospital patients 487 (57%) were HIV-1-positive. HIV-1 seroprevalence was 55% for those who were identified or believed to be HIV-1-negative on admission as indicated on the medical chart. HIV-1 seroprevalence in the clinic population decreased initially, but later increased, although not to study onset levels. CONCLUSIONS: There is considerable overlap between the TB and HIV epidemics in New York City; a part of the increasing TB incidence may be independent of HIV coinfection. The control of TB will necessitate prompt diagnosis of TB and HIV-1, appropriate TB treatment and/or chemoprophylaxis, and a greater commitment to tackle the social conditions associated with the spread of the disease.

Adolescent↗