SEARCH · PubMed Health

Results for “Latent diffusion”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

PubMed1979

[Clinical morphology of early breast cancer].

True early forms of mammary cancer include tumours undetectable in routine clinical examinations and histologically presenting intraductal and lobular cancer (cancer in situ and with beginning invasion) in the absence of metastases. Parallel histological and cytological examinations and cytospectrophotometric determination of the DNA content increase the validity of the differential diagnosis between benign displasias and carcinoma in situ. Stages of composite clinico-roentgenilogical and morphological diagnosis of early mammary cancer have been developed. Two mammographic signs: accumulations of finest calcinates and filamentous tumour node less than 10 mm in diameter, permit to diagnose clinically latent cancer which has two forms of growth, diffuse and nodular. The diffuse form in some cases presents a stage preceeding the nodular form.

Breast Neoplasms↗

PubMed1977

[Excretion of alanine aminopeptidase in the urine after administration of lysosomotrophic substances in patients with latent or florid pyelonephritis].

It is described a test for the presence of diffuse nephropathies which is based on the fact that after application 20 ml of the renal diatrizoate X-ray contrast medium Visotrast or of 500 ml of a 10% mannitol solution in patients with preexisting renal diseases appear reversible, diagnostically relevant increases of the alanine aminopeptidase excretion with the urine. In persons with healthy kidneys the excretion of enzymes changes insignificantly. The increased excretion of alanine aminopeptidase is also observed in patients with latent pyelonephritis and is traced back to the increased formation of an osmotic nephropathy in patients with preexisting nephropathies.

Alanine↗

PubMedDate not supplied

Opening the black box: measuring hospital information technology capability.

Recently, health care investment in information technology (IT) has experienced a significant increase. Paralleling this increase has been an increase in IT capabilities. Despite the interest in and promises of IT in the health care setting, there is a paucity of empirical research that has attempted to define an organizational measure of IT capability. The dearth of research has contributed to the traditional belief that IT is perceived as a "black box," whereby organizational resources enter the box as "inputs" and are somehow transformed into positive outcomes for an organization. However, for positive outcomes to be realized, these outcomes must be measurable. This research uses a stakeholder perspective to develop a theoretically specified measure of IT capability. A latent construct, IT munificence, is proposed using tenets from diffusion of innovation theory and strategic contingency theory. The construct is tested using a sample of 1,545 acute care hospitals located in the United States. IT munificence fits the study data well, supporting the hypothesis that IT munificence represents a strategy of hospital IT capability.

Diffusion of Innovation↗

PubMed1982

Disseminated pulmonary adiaspiromycosis identified in bioptic material from the lung.

A disseminated form of pulmonary adiaspiromycosis was estimated in a 48 year old miner. The origin of a hypersensitivity mainly of an immediate allergic type became evident during an immunological examination and was partly indicated also by the tissue reaction and by elevated level of serum IgE (480 I.U.). Of great interest was the finding of a coagulation necrosis in the bioptic material. An examination of functions disclosed signs of a moderate obstruction which was latent when first observed with normal value of lung diffusion capacity. Its activation during stress was indicated by an increase in the value both of the residual volume and the IGV to the upper border of their limits. No apparent changes occurred in the disease during our two-year-investigation. Neither the total state of the patient nor the x-ray picture reflected the effect of a prolonged treatment with antituberculotics.

Antitubercular Agents↗

PubMed1993

[Iodine-induced hyperthyroidism in urology caused by using roentgen contrast media. Risks and prevention].

The presence of functionally autonomous portions of the thyroid is a precondition for the occurrence of iodine-induced hyperthyroidism after the administration of i.v. contrast media, in the form either of latent immunogenic hyperthyroidism (Basedow's disease) or of localized or diffuse autonomy. The normal thyroid can compensate an iodine excess in multiple ways. In the malfunctioning thyroid, however, autoregulation mechanisms may fail, resulting in complicated forms of hyperthyroidism. In Germany autonomy-correlated hyperthyroidism occurs much more often than in other countries in which sufficient alimentary iodine is present. Especially in elderly patients with long-standing nodular goitres, there is an elevated risk of iodine-induced hyperthyroidism arising from thyroidal autonomy. These cases may differ from those seen in younger patients. An existing hyperthyroidism may worsen dramatically after administration of contrast media. To prevent an iodine-induced thyrotoxic crisis, contrast media should only be given to patients with latent of manifest hyperthyroidism when vital indications are present, and then only after thyrostatics have been administered. To evaluate the morphology of the renal collecting system and ureter in these cases a retrograde rather than an intravenous pyelography should be performed. When this is combined with determination of serum creatinine and creatinine clearance, functional and morphological evaluation, respectively, of the upper urinary tract are possible.

Aged↗

PubMed2026

Conditional Diffusion Model-Based Method for Annotation of Antibiotic Resistance Gene Properties.

The crisis of bacterial antibiotic resistance, which has led to a decline in the effectiveness of antibiotics originally used to combat bacterial infections, has emerged as an urgent challenge for public health. Antibiotic resistance genes (ARGs) are one of the key reasons for bacteria to develop resistance to antibiotics. Therefore, accurately identifying and annotating the critical properties of ARGs is of great importance for addressing the antibiotic resistance emergency. Although existing deep learning models demonstrate remarkable effectiveness in extracting local features from sequence data, they still face limitations in the capacity to further gain the enriched latent representations within the data. To address the critical challenge of extracting higher-quality representations from ARGs sequence data, we propose a novel ARGs properties annotation method based on the conditional diffusion model which is used to learn latent representations through domain-specific knowledge injection. Specifically, during the conditional information integration phase, we systematically incorporate ARGs' domain knowledge to guide the diffusion process in generating high-quality latent representations. To overcome information redundancy caused by direct concatenation of conditional information and intermediate features, we design a cross-attention mechanism that enables feature fusion between heterogeneous information sources, thereby enhancing further the quality of obtained representations. Experimental results on widely used data sets demonstrate the framework's effectiveness in achieving superior prediction performance compared to existing methods.

Anti-Bacterial Agents↗

PubMed1999

Thermodynamically reversible generalization of diffusion limited aggregation.

We introduce a lattice gas model of cluster growth via the diffusive aggregation of particles in a closed system obeying a local, deterministic, microscopically reversible dynamics. This model roughly corresponds to placing the irreversible diffusion limited aggregation model (DLA) in contact with a heat bath. Particles release latent heat when aggregating, while singly connected cluster members can absorb heat and evaporate. The heat bath is initially empty, hence we observe the flow of entropy from the aggregating gas of particles into the heat bath, which is being populated by diffusing heat tokens. Before the population of the heat bath stabilizes, the cluster morphology (quantified by the fractal dimension) is similar to a standard DLA cluster. The cluster then gradually anneals, becoming more tenuous, until reaching configurational equilibrium when the cluster morphology resembles a quenched branched random polymer. As the microscopic dynamics is invertible, we can reverse the evolution, observe the inverse flow of heat and entropy, and recover the initial condition. This simple system provides an explicit example of how macroscopic dissipation and self-organization can result from an underlying microscopically reversible dynamics. We present a detailed description of the dynamics for the model, discuss the macroscopic limit, and give predictions for the equilibrium particle densities obtained in the mean field limit. Empirical results for the growth are then presented, including the observed equilibrium particle densities, the temperature of the system, the fractal dimension of the growth clusters, scaling behavior, finite size effects, and the approach to equilibrium. We pay particular attention to the temporal behavior of the growth process and show that the relaxation to the maximum entropy state is initially a rapid nonequilibrium process, then subsequently it is a quasistatic process with a well defined temperature.

Journal Article↗

PubMed1990

Papillary carcinoma of thyroid: classical and variants.

Papillary carcinoma, the commonest primary cancer of thyroid, exhibits a broad morphological spectrum. In this review, the clinicopathological features of papillary carcinoma, classical and its variants (follicular, solid, cribriform, variant with exuberant nodular fasciitis-like stroma, encapsulated, diffuse sclerosing, diffuse follicular, tall cell, columnar cell, oxyphil cell, "dedifferentiated", occult, latent and microcarcinoma) are summarized.

Carcinoma, Papillary↗

PubMed1995

The role of increasing detection in the rising incidence of prostate cancer.

OBJECTIVE: To assess the reasons for the dramatic surge in prostate cancer incidence from 1986 to 1991. DESIGN: Population-based study of incidence rates and procedures used to detect and diagnose prostate cancer derived from Medicare claims data and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program from 1986 to 1991. SETTING: Four SEER areas (Connecticut; Atlanta, Ga; Detroit, Mich; and Seattle--Puget Sound, Wash) covering approximately 6% of the US population. PARTICIPANTS: A 5% random sample of male fee-for-service Medicare beneficiaries aged 65 years and older without cancer, and all men with prostate cancer diagnosed at 65 years of age and older residing in the four areas. MAIN OUTCOME MEASURES: The age-adjusted rates of prostate cancer incidence, prostate needle biopsy, transurethral resection of the prostate, serum prostate-specific antigen (PSA) testing, and transrectal ultrasound. RESULTS: The age-adjusted incidence rate of prostate cancer among men aged 65 years and older in the four SEER areas rose 82% from 1986 to 1991, with the largest annual increases occurring in 1990 (20%) and 1991 (19%). Prostate needle biopsy rates increased while the use of transurethral resection of the prostate declined from 1986 to 1991. The rising needle biopsy rate has been driven by an exponential increase in PSA testing in the general population from 1988 to 1991 and, to a much lesser extent, the increasing use of transrectal ultrasound since 1986. The use of PSA or transrectal ultrasound has increased across age and race groups and in different geographic areas. However, there remain wide geographic variations in the use of PSA screening. CONCLUSIONS: The recent dramatic epidemic of prostate cancer is likely the result of the increasing detection of tumors resulting from increased PSA screening. The magnitude and rapidity of the incidence rise suggest that changes in the intensity of medical surveillance is the most plausible explanation for this trend. IMPLICATIONS: The rapid diffusion of screening interventions that have the ability to detect latent asymptomatic disease leads to important concerns regarding costs and patient quality of life for men aged 65 years and older. Geographic variability in the adoption of PSA testing underscores uncertainty and disagreement about its value for reducing prostate cancer mortality. More research is required to determine the effectiveness of screening for prostate cancer.

Age Distribution↗

PubMedDate not supplied

[Clinico-morphologic heterogeneity of minimal changes in glomerulonephritis].

60 kidney biopsies from patients with minimal changes were investigated by light-, electron- and immunofluorescent microscopy. The clinical picture in 41 patients was nephrotic syndrome; 10, 6 and 3 patients had mixed, hematuric and latent forms, respectively. In 45 of 60 biopsies focal or diffuse deposits of immune complexes in basal membrane and glomerular mesangium were found. 15 cases proved to be immunonegative. Depending on various combinations of G, A, M-immunoglobulins, C3-fraction of complement, their location in the glomerulus and type of the immune complex fluorescence, one can say about glomerulonephritis, focal segmental glomerular hyalinosis or membranous nephropathy. The immunonegative group of minimal changes requires an electron-microscopic study which may determine the nosology of minimal changes: lipoid nephrosis, disease of thin basal membranes, hypoplastic dysplasia. Recognition of glomerulonephritis and independent forms of glomerulopathies in minimal changes having their immunohistochemical characteristics and other features suggest clinicomorphological heterogeneity of minimal changes.

Adolescent↗

PubMed1995

Association of Epstein-Barr virus latent membrane protein and Hodgkin's disease in Mexico.

Epstein-Barr virus (EBV) has been demonstrated in association with Hodgkin's disease (HD) in approximately 40 to 50% of cases in series from North America, Europe, and Japan. However, few data are available concerning this association in developing countries. Recent studies, including mostly a pediatric population from Peru and a pediatric population from Honduras, showed a higher percentage of EBV positivity compared with those in developed countries. To determine the prevalence of EBV in Hodgkin's disease in a Mexican adult population, we analyzed 50 formalin-fixed, paraffin-embedded cases of HD by a three-step technique using a monoclonal antibody to the latent membrane protein of EBV. All the cases were confirmed immunophenotypically as HD (CD15+ and/or CD30+, CD45-). Reed-Sternberg cells and variants were positive for LMP in 35 cases (70%). The staining was found both on the cell surface and/or within the cytoplasm with enhancement of the Golgi area. EBV latent membrane protein was found in 1/1 case (100%) of diffuse lymphocyte-predominant HD, 10/20 cases (50%) of nodular-sclerosis, 18/22 cases of mixed-cellularity (81%), and 6/7 (86%) cases of lymphocyte-depleted HD. Our results show a high prevalence of EBV in HD in this Mexican adult population. All histologic subtypes of HD in the population analyzed appear to be strongly associated with EBV, in contrast to the strong association of mixed cellularity HD in developed countries. Patient age and gender were not predictive of the presence of EBV.

Adolescent↗

PubMed1996

Identification of Epstein-Barr virus lytic activity in post-transplantation lymphoproliferative disease.

Post-transplantation lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation. The majority of these lymphoid expansions are associated with latent Epstein-Barr virus (EBV) infection, but lytic activity may play an important role in initiating the disease process. Forty-eight specimens from 44 allograft recipients with EBV-associated PTLD were studied by immunohistochemical techniques for EBV lytic proteins, by use of monoclonal antibodies specific for the immediate early latent to lytic switch protein BZLF1 and two early antigens (diffuse and restricted). In addition, the specimens were studied by in situ hybridization for EBV DNA by use of an oligonucleotide probe for the EBV NotI tandem DNA repeats, whose expression seems confined to lytic infection. Thirty specimens were studied by in situ hybridization for immediate early (BZLF1) and late (gp350/220) lytic mRNA transcripts. Ninety-two percent of the specimens demonstrated at least one of the lytic EBV proteins. BZLF1 protein was seen in 81% of the specimens, whereas 54% and 52% of specimens expressed diffuse and restricted early antigens, respectively. Twenty-nine percent of specimens contained all three of the lytic proteins. The NotI tandem DNA probe produced staining in 88% of the specimens, whereas immediate early and late lytic transcripts were seen in 90% of the specimens. The amount of lytic activity did not significantly vary with PTLD histopathologic findings, but monomorphous proliferations localized to a single anatomic site showed a slightly lower reactivity with the antibodies and nucleic acid probes. Lytic activity was highest in patients with multisite disease, although this difference was not statistically significant. In conclusion, a significant proportion of patients with PTLD expressed lytic nucleic acids and proteins. Further work is necessary to analyze the role of lytic EBV infection in the initiation and maintenance of lymphoproliferative disorders in allograft recipients.

Adolescent↗

PubMed2000

Thermal and chemical diffusion in the rapid solidification of binary alloys

Solidification of binary alloys is characterized by the necessity to reject away from the advancing front two conserved quantities: the latent heat released at the solid-liquid interface and the solute atoms that cannot be accommodated in the solid phase. As thermal diffusion is much faster than chemical diffusion, the latter is generally assumed to be the rate limiting mechanism for the process, and the problem is addressed through the isothermal approximation. In the present paper we use the phase-field model to study the planar growth of a solid germ, nucleated in its undercooled melt. We focus on the effects of a noninstantaneous thermal relaxation. The steady growth predicted at large supersaturation in the isothermal limit is prevented. Depending on the value of the Lewis number the growth rate is limited by either mass or heat diffusion; in the latter case we observe a sharp transition between two different regimes, in which originates a nonmonotonic time dependence of the interface temperature. The effects of this transition reflect in the composition of the solidified alloy.

Journal Article↗

PubMedDate not supplied

Herpes simplex virus in the saliva of peripheral Bell's palsy patients.

UNLABELLED: The first herpes virus to be described was types 1 and 2, whose denomination is herpes simplex 1 and 2 or HSV-1 and HSV-2. These viruses have specific biological characteristics, such as the ability to cause different kinds of diseases, as well as to establish hosts latent or persistent lifetime infections and also of being reactivated, causing lesions that can be located at the same site of the initial primary infection or close to it. It is suggested that this virus reactivation in the geniculate ganglion may be related to Bell's palsy. In this situation, the viruses that would be latent in this ganglion, would suffer reactivation and replication, then be diffused through the facial nerve and its branches, among them the chorda tympani nerve, which by stimulating salivary secretion would enable the identification of the viral DNA in the patients saliva. Until recently, a great number of patients was diagnosed as holders of this kind of paralysis, named idiopathic or Bell's palsy. With the introduction of the technique studying the viral DNA by Polymerase Chain Reaction (PCR), several authors have found herpes simplex virus type I DNA in the cerebrospinal fluid, in the lachrymal secretion, in the saliva and in the geniculate ganglia of patients with Bell's palsy. AIM: observe the occurrence of herpes simplex type I virus using PCR technique in the saliva of patients with Bell's palsy and relating it to the clinical evolution of these cases. METHODOLOGY: We evaluated 38 patients with Bell's palsy submitted to anamnesis, clinical and ENT examination and saliva sampling for viral DNA detection by PCR technique. The control group was ten normal adults. RESULTS: We found positive viral DNA in 11 cases out of the 38, which corresponded to 29% of the sample. This result was statistically significant if compared to the control group, in which we did not find any positive case. CONCLUSION: The end result was that the presence of HSV-1 in the saliva of patients with Bell's palsy indicating that the viral reactivation can be the etiology of this disease. The detection of the virus in these patients saliva does not influence the disease prognosis.

Acute Disease↗

PubMed2003

[Virological, epidemiological and pathogenic aspects of human polyomaviruses].

VIROLOGICAL ASPECTS: Human polyomaviruses (BK virus and JC virus), together with simian polyomaviruses (SV40 virus) share 75% of genomic homology. Their in vivo and in vitro genomes vary. Molecular analyses have identified several genotypes, some of which appear related to the development of viral diseases. Genomic modifications of the regulation area might provide the BKv with a pathogenic aspect thus enhancing the induction of tubulo-interstitial nephropathies in renal transplant recipients. EPIDEMIOLOGY: Human polyomaviruses are ubiquitous and exhibit a sero-prevalence of 60 to 80% in adults. Following a primary infection via the respiratory tract in childhood, these viruses are diffused in the blood using the B-lymphocytes during their latent stage in the urogenital tract. The reactivation that occurs after several years is asymptomatic and urinary excretion of BKv is observed in 4 to 6% of immunocompetent patients. PATHOGENIC POTENTIAL: Human polyomaviruses have a cytopathogenic effect on the urothelium and epithelium of renal transplant recipients. Infection by BKv may provoke hemorrhagic cystitis or urethral stenosis. The JCv is the cause of progressive multifocal leuko-encephalitis. The BKv (and less frequently the JCv) is responsible for tubulo-interstitial nephritis possible leading to renal transplant loss. They also have an oncogenic effect and their implication in the origin of tumours is the subject of many studies.

Adult↗

PubMed1985

[Tubulointerstitial component of chronic glomerulonephritis. Clinico-morphological comparisons].

A total of 179 patients with chronic glomerulonephritis were examined for the development of the tubulo-interstitial component (TIC) of the disease. It was established that the rate of the development and intensity of the TIC are linked with different morphological variants of GN and increase successively in mesangiomembranous, membranous, mesangioproliferative, mesangiocapillary (and lobular) GN, reaching a maximum in diffuse fibroplastic GN. In patients with no TIC, the hematuric and latent forms of CGN were mostly encountered. The disease took a stable course, with a frequent occurrence of improvements and remission. The 5-year survival was 100%. In patients with a moderate TIC, the nephrotic form of CGN was encountered more often than in other patients. As regards other characteristics, this form occupied an intermediate position, with the 5-year survival rate amounting to 91%. Patients with a pronounced TIC were marked by progressive CGN, which was largely observed in the hypertonic and mixed patterns of the disease. The three-year survival amounted to 34% in this case. The TIC of CGN is an important prognostic factor and the dissimilar course of different morphological variants of CGN is accounted, to a considerable degree, for by the dissimilar rate of TIC development.

Basement Membrane↗

PubMed1998

Epstein-Barr virus expression within keratinizing nasopharyngeal carcinoma.

Three stages of maturation can be seen in keratinizing nasopharyngeal carcinomas. These stages are similar morphologically to basal cells, intermediate and superficial squamous cells seen in normal squamous epithelium. Taking advantage of such a diverse tumour cell population, 10 keratinizing nasopharyngeal carcinoma (NPC) were examined by in situ hybridization for the presence of latent Epstein-Barr Virus (EBV) using EBV encoded RNAs (EBERs) and by immunohistology for the presence of EBV early antigen-diffuse (EA-D) and the 350/220 kd membrane glycoprotein of the EBV. The basal cell-like tumour cells are mainly infected latently with the virus; viral replication was found in isolated intermediate squamous cells, whilst superficial squamous cells are largely depleted of all the viral markers. We used a control series of nonkeratinizing nasopharyngeal carcinomas composed of undifferentiated and poorly differentiated tumour cells and EBV latency was present in these tumours. Viral replication was detected by RT-PCR, in the undifferentiated tumours but viral replication was not seen by immunohistology. The possible relationship between EBV life cycle in these tumours and tumour cell differentiation is discussed in the light of these findings.

Antibodies, Monoclonal↗

PubMed1991

[Real errors in the diagnosis of well-known diffuse kidney lesions and their causes (critical comments. The author's own observations)].

Analysis of the data obtained during a comprehensive examination of a great number of nephrologic patients during 1964-1989 permitted the author to draw a conclusion that a considerable part of errors in the diagnosis of diffuse renal lesions (DRL) are primarily made as a result of inadequate choice of examination methods that might contribute to the solving of a diagnostic problem; an insufficiently clear idea of the resolving power of those methods, and violation of the succession of their use. Erroneous interpretation of the patient's complaints and disease history we face sometimes, inadequate competence in the assessment of the clinical symptoms and laboratory data are of no less importance. All these moments are supported by the author's own observations. Special emphasis is laid on the causes of diagnostic errors occurring in the diagnosis of primary chronic pyelonephritis (PCPN), especially of its latent form, renal amyloidosis, focal nephritis, toxic or toxico-infectious kidneys, concomitant diffuse renal lesions, and on the etiology of the nephrotic syndrome (NS). The author substantiates inaccuracy of the concept of a potential development of the NS in patients suffering from PCPN. The author holds that if PCPN patients manifest the NS, it means that PCPN may be coupled with certain DRL complicated by the NS.

Acute Disease↗