PubMed Health⌕ Search

Biomedical subjects

U Gross

Publications and source records attributed to U Gross.

At least 19 recordsLinked to original sources
PubMed1992

[Taenia crassiceps infection in AIDS].

A 33-year-old patient with AIDS, and a history of episodes of Pneumocystis carinii pneumonia and cerebral toxoplasmosis, developed a subcutaneous paravertebral infiltrate, which at first resembled a haematoma. Over a period of several weeks, the lesion spread to cover almost the entire back. Initially, numerous investigations failed to reveal the aetiology. His general condition worsened progressively, and intermittent bleeding into the soft tissue of the back occurred, requiring transfusion. This was associated with the development of an isolated deficiency of clotting factor V and a fall in Quick values to 10%. On the 22nd day after admission, the infiltrate ruptured spontaneously, releasing blood and a large number of whitish spherical masses 2-3 mm in diameter. These were identified as Cysticerci longicolles, the larval form of Taenia crassiceps, a tapeworm occurring in Canidae. The blood clotting values returned to normal within two days of incision of the infiltrate and commencement of therapy with mebendazole (6 g/day) and praziquantel (3.6 g/day). The infiltrate subsequently regressed almost completely. After combination treatment for 2 weeks, treatment was continued with praziquantel alone, which, however, the patient stopped himself after 10 weeks. A recurrence at the same site 4 months later was successfully treated with a further course of mebendazole and praziquantel.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Modulation of matrix vesicle enzyme activity and phosphatidylserine content by ceramic implant materials during endosteal bone healing.

This study examined effects of bone bonding and nonbonding implants on parameters associated with matrix vesicle-mediated primary bone formation, matrix vesicle alkaline phosphatase and phospholipase A2 specific activities, and phosphatidylserine content. Tibia marrow ablation followed by implantation of KG-Cera, Mina 13 (bonding), KGy-213, or M 8/1 (nonbonding) was used as the experimental model. Postsurgery, matrix vesicle-enriched microsomes (MVEM) were isolated from implanted and contralateral limbs. MVEM alkaline phosphatase and phospholipase A2 were stimulated adjacent to bonding implants with similar, though reduced, effects contralaterally. Alkaline phosphatase exhibited slight stimulation in nonbonding tissue; phospholipase A2 was inhibited or unchanged in treated and contralateral limbs. Phosphatidylserine content of MVEM was differentially affected by the implant materials. Thus, MVEM are modulated by implant materials locally and systemically. The data demonstrate that the model is a biologically relevant diagnostic for assessing the tissue/implant interface, primary calcification is affected by implant materials, and implant-specific effects are detected in the contralateral unimplanted limb.

Alkaline Phosphatase↗
PubMed1992

Improved sensitivity of the polymerase chain reaction for detection of Toxoplasma gondii in biological and human clinical specimens.

The aim of the present study was to improve the sensitivity of the polymerase chain reaction for detection of Toxoplasma gondii in biological and clinical specimens. Using a pair of primers amplifying a 634 bp fragment of the B1 gene of this parasite, it was possible to detect ten parasites in 100 microliters of sample suspensions containing a high concentration of concomitant host cells. A comparison of different DNA purification methods indicated that cell-rich clinical specimens intended for use as samples for the polymerase chain reaction should be digested with proteinase K prior to DNA amplification. By using the described sample preparation methods and the polymerase chain reaction, Toxoplasma gondii DNA was demonstrated in ten of 52 clinical specimens of patients with clinical or serological indications of toxoplasmosis.

Animals↗
PubMed1992

Effect of titanium implants on primary mineralization following 6 and 14 days of rat tibial healing.

The effect of pure commercial titanium implants on the process of primary mineralization was studied. This was examined by insertion of titanium implants into rat tibial bone after ablation. The effects of the titanium were studied through the behaviour of extracellular matrix vesicles (MV). Methods of morphometric analysis at the TEM level were applied. The insertion of titanium implants was followed by an increase in the number of MV as well as vesicular diameter and by a decrease in vesicular distance from the calcified front when compared to normal healing. These results suggest that the process of MV maturation around titanium implants was delayed when compared to normal primary bone formation during bone healing. The delay in mineralization was compensated by an increase in vesicle production, resulting in an enhancement of primary mineralization by the titanium.

Animals↗
PubMed1992

In vivo regulation of matrix vesicle concentration and enzyme activity during primary bone formation.

In vivo regulation of matrix vesicles (MV) during primary bone formation was examined using tibial marrow ablation in rats as the experimental model. The effects of bone-bonding and nonbonding implants on the number of MV/micron 2 of matrix and the alkaline phosphatase (ALPase) and phospholipase A2 (PA2) activities of MV-enriched microsomes (MVEM) isolated from the healing bone were studied. MV concentration, ALPase, and PA2 were increased by bone-bonding implants by day 3 post-surgery; a similar effect was seen in the contralateral limb, but at a lower magnitude. Nonbonding implants had no effect at day 3 and decreased MV concentration and PA2 activity at later time points; the same behavior was observed in the contralateral limb. These results demonstrate that MVs are influenced in a differential manner by implant materials, both locally and systemically, and can be regulated during primary mineralization.

Alkaline Phosphatase↗
PubMed1992

Cushing syndrome-associated pheochromocytoma and adrenal carcinoma. An immunohistological investigation.

Seven adrenal carcinomas and seventeen pheochromocytomas (PHs), two of which were clinically associated with a Cushing's syndrome and one associated with multiple endocrine neoplasia Type II (MEN-II), were investigated immunohistologically with a panel of antibodies against intermediate filament proteins, a proliferation-associated nuclear antigen (Ki-67), neuroendocrine tumor markers, and different hormones on paraffin-embedded tissue sections and, from 19 cases, also on frozen tissue sections. Synaptophysin proved to be the most reliable tumor cell marker on both snap-frozen and paraffin-embedded tissue but, like antibodies against NSE, yielded unspecific stainings in the carcinomas. The two Cushing-associated pheochromocytomas (CaPH) showed the same immunohistological profile as the other PHs, except one chromogranin-negative tumor. Five PHs showed weak reactivity for calcitonin, one for serotonin, and two for a-HCG in small amounts. All PHs lacked other hormone expression, including ACTH. The average growth fraction was small (2.2%) in 13 cases, but 80% of the tumor cells were proliferating in one case of CaPH. Adrenal carcinomas showed only weak or no expression of keratin in one case, a homogenous or droplet, non-filamentous cytoplasmic staining with antibodies against neurofilament in frozen tissue section, and they were completely chromogranin-negative. The average growth fraction was 7.6% in 5 cases.

Adolescent↗
PubMed1992

The development of a posttransplant TLI treatment strategy that promotes organ allograft acceptance without chronic immunosuppression.

The effectiveness of fractionated TLI in promoting allograft tolerance without chronic drug therapy is well established experimentally. TLI has not been widely applied in clinical transplantation, largely due to logistic and medical limitations of pretransplant TLI conditioning. Potential use of posttransplant TLI (PT-TLI) has not been critically evaluated. In this study we investigated PT-TLI in combination with rabbit antithymocyte globulin (RATG) in the absence of chronic immunosuppressive drugs as a strategy for inducing long-term kidney allograft acceptance. Recipients were studied with and without infusion of DR-CD3- donor bone marrow cells (DBMC). Normal rhesus monkeys, which received no pretransplant treatment, underwent bilateral intrinsic nephrectomy and splenectomy at the time of transplantation. RATG was administered daily for 3-5 consecutive days beginning on day 0. A total dose of 500-625 cGy of fractionated TLI was given in 4-5 treatments at 125 cGy per day beginning on day +1. Whereas neither PT-TLI nor RATG monotherapy induced long-term graft acceptance in splenectomized recipients, the combination of these modalities was remarkable in promoting long-term allograft acceptance without immunosuppressive drug therapy. Of 4 recipients given RATG x 5, splenectomy and PT-TLI, all were free of acute rejection. Of these, 3/4 had graft survivals greater than 100 days, 2/4 were greater than 150 days and 1/4 greater than 365 days. Of 5 recipients given this treatment plus an infusion of DR-CD3-DBMC, 4/5 grafts survived greater than 150 days and 3/5 still have normal functioning grafts at greater than 365 days. PT-TLI accentuated and prolonged changes in PBL subpopulations that were initially affected by RATG. Depressed levels of CD3+ cells were present for 4-5 months, with large numbers of circulating CD4+CD3- and especially CD8+ CD3- cells. In addition, antibody responses to RATG and alloantigens were suppressed in PT-TLI-treated recipients. Overall, the combination of PT-TLI, splenectomy, and RATG was found to be effective in promoting long-term allograft acceptance without chronic immunosuppressive drug therapy. The infusion of DR-CD3- DBMC in recipients treated with PT-TLI, RATG and splenectomy appeared to further increase the incidence of stable long-term survivors. If infectious complications can be improved, this approach may provide a clinically applicable posttransplant treatment strategy for inducing functional allograft tolerance.

Animals↗
PubMed1992

Improved serological diagnosis of Toxoplasma gondii infection by detection of immunoglobulin A (IgA) and IgM antibodies against P30 by using the immunoblot technique.

Immunoglobulin M (IgM) and IgA antibodies against the major surface protein of Toxoplasma gondii were determined in a total of 195 human sera and five human cerebrospinal fluids by using a P30 membrane extract and the immunoblot technique. By using two different T. gondii strains (RH and BK) simultaneously as antigens, we were able to demonstrate diagnostically important strain-specific human antibody responses in 4.5% of the samples tested. A comparison of the immunoblot technique with an IgM immunocapture enzyme-linked immunosorbent assay demonstrated that the IgM and IgA immunoblot seems to be of advantage in the diagnosis of acute toxoplasmosis in certain groups of patients, especially in the diagnosis of cerebral toxoplasmosis in patients with AIDS. The immunoblot technique described is easy to perform and might be useful as an additional serological assay for routine diagnosis of T. gondii infections.

Animals↗
PubMed1992

Blood substitutes made on the basis of perfluorocarbons inhibit intracellular energy generation.

Although perfluorocarbons (PFC) are chemically inert, toxic reactions are observed on using them as fluorocarbon emulsions in blood substitutes. Six to twelve hours after exchanging about half of the circulating blood of conscious rats pathobiochemical reactions occur despite a high interarterial oxygen pressure. They indicate the disturbance of intracellular energy generation, which is characterized by a decrease in ATP, increase in ADP, inorganic phosphate and potassium, increase in NADH and lactate. Impurities of perfluorocarbons and effects of the surfactant were excluded to be causes of this disturbance. The following hypotheses were proposed: Storing of perfluorocarbons in the mitochondrial membrane decreases the ATP-forming proton gradient on the membrane and the electron transport in cytochromes is disturbed, respectively.

Adenosine Triphosphate↗
PubMed1992

[New views on the pathogenesis and diagnosis of toxoplasmosis].

T. gondii is one of the most occurring human pathogenic parasites in Europe. While the majority of immunocompetent individuals with T. gondii infection do not present clinical symptoms, congenital toxoplasmosis and reactivation of a latent infection in immunocompromised patients (i. e. patients with AIDS) are of high clinical relevance. A classification of T. gondii isolates is not available so far, although it was possible to demonstrate strain differences by the use of several methods, i. e. by using monoclonal antibodies. T. gondii seems to be able to infect any mammalian cell. Host cell-derived as well as parasite-derived factors seem to be important for the contact between host cell and parasite and the subsequent internalization. Following invasion, T. gondii is located within a parasitophorous vacuole that does not fuse with lysosomes. The multiplication rate of these obligately intracellular growing parasites decreases during conversion from the tachyzoite stage to the bradyzoite stage. Finally, the bradyzoites-harbouring cysts persist for the lifetime of the host. Reconversion from bradyzoites to tachyzoites may occur in immunocompromised patients. Probably, IFN-gamma is involved in this process. In addition to serological methods, direct detection of T. gondii using PCR or demonstration of circulating antigens might be routinely used as diagnostical tools in the future. Determination of specific IgA antibodies, which can be evaluated using the immunoblot technique, seem to be important for early serological diagnosis. The use of recombinant antigens might be helpful in future diagnosis to circumvent discrepancies between serological test results which could have resulted from strain-specific differences.

Animals↗
PubMed1991

Effect of glass ceramic and titanium implants on primary calcification during rat tibial bone healing.

The effect of bone bonding (KG Cera, Mina 13, and titanium) and nonbone bonding (KGy-213, M 8/1) implants on primary calcification in endosteal bone was examined by comparing changes in the morphometry of matrix vesicles to those occurring during normal bone healing following ablation of rat tibial marrow. The concentration of matrix vesicles, their diameter, and their distance from the calcification front were determined using computerized cytomorphometry at the transmission electron microscopic level. The results demonstrated that bone bonding materials supported an increase in matrix vesicle concentration when compared with control bone at 6 and 14 days postimplantation. At 14 days, there were fewer matrix vesicles in the bone adjacent to the nonbonding implants. Though matrix vesicle diameter decreased in the control bone between 6 and 14 days, it increased in all of the experimental samples. Diameters were significantly greater in the bone bonding samples at 14 days and significantly lower in the nonbonding samples at 6 days. Distance from the calcification front decreased between 6 and 14 days in all groups except in bone adjacent to the KGy-213 implants. In bone adjacent to the bone bonding implants, distance from the calcification front was comparable to or further than that of control bone; in the nonbonding samples it was closer to the calcification front. These results demonstrate that production and maturation of matrix vesicles is influenced in a differential manner by the presence of implant materials.

Animals↗
PubMed1991

Identification of a virulence-associated antigen of Toxoplasma gondii by use of a mouse monoclonal antibody.

A monoclonal antibody generated against the mouse-lethal RH strain of Toxoplasma gondii was developed. Tachyzoites of virulent and avirulent T. gondii isolates grown in permanent macrophage cell cultures were examined for differences in reactivity with this antibody. Virulence of these Toxoplasma isolates was quantified by injecting different numbers of tachyzoites into NMRI mice and observing the animals for signs of infection or death. The monoclonal antibody identified a 23-kDa antigen expressed by the mouse-lethal strains BK and RH, whereas this antigen was not detected in low-mouse-virulent strains, which were all clinical isolates from Europe. Using Western blot (immunoblot), immunofluorescence, and immunoelectron microscopy, we localized the 23-kDa antigen to the membrane compartment. From these results, we suggest that this 23-kDa antigen is a marker of strain virulence upon which a virulence classification of T. gondii may be based.

Animals↗
PubMed1991

Improved xenograft survival with continuous infusion deoxyspergualin and RATG.

The critical shortage of available donor organs is the major limit to current allogeneic transplantation. Xenografting has the potential to overcome this difficult problem. Suppressing the vigorous rejection response remains a major obstacle to the clinical application of xenografting, 15-Deoxyspergualin (DOSP), a potent new immunosuppressive agent has been shown to be effective in allogeneic and xenogeneic experimental models. This study tests DOSP in combination with rabbit antithymocyte globulin (RATG) in the hamster-to-rat cardiac xenograft. Results show that combination therapy with DOSP/RATG was superior to treatment with either agent alone (p less than .05). Optimal graft prolongation (20.9 days versus control of 3.1 days, p less than .05) was achieved with combination therapy of RATG and DOSP 2.5 mg/kg day-1 by continuous infusion.

Animals↗
PubMed1990

The effect of glass-ceramic implants on matrix vesicle calcification after two weeks of rat tibial bone healing.

Type, size and distribution of extracellular matrix vesicles (MV), known mediators of primary calcification, were studied around bone-bonding and metal-oxide containing, nonbonding, glass-ceramic implants. This was performed in order to further understand the different effects of implants on bone healing. At 14 days after implantation in adult rat tibial bone the effects of different implants on MV were studied by transmission electron microscopy and computerized morphometry. A total number of 4607 MV in 245 electron micrographs were counted and grouped according to diameter, distance from the calcifying front, and classified as four types: "empty," "amorphous," "crystal," and "rupture." The sequence of types according to diameter and distance was recorded as follows around both implants tested: "rupture" MV were the closest to the front with the largest diameter, followed by "crystal," "amorphous," and "empty," MV with the largest distance from the front and the smallest diameter. Most vesicles were concentrated in a distance of less than 2.4 microns from the front and between diameters of 0.06 microns and 0.22 microns. The noncalcified extracellular matrix around bone-bonding implants contained more MV than the matrix around the nonbonding type (26.24 MV/10 microns2 and 18.76 MV/10 microns2). MV distribution according to types showed that around bonding implants there was a higher percentage of "crystal" and a lower percentage of "rupture" when compared to the nonbonding type. These results indicate that bonding implants affect osteoblastic function by increasing the vesicular number and retardation of intravesicular crystal formation. It might be suggested that bonding implants induce an increase in the process of primary calcification and a decreased rate of crystal formation resulting with the highest organization of the healing bone.

Animals↗
PubMed1990

The relationships between selected anthropometric and socio-economic data in schoolchildren from different social strata in Rio de Janeiro, Brazil.

The nutritional status according to anthropometric data was assessed in 756 schoolchildren from 5 low-income state schools and in one private school in the same part of Rio de Janeiro, Brazil. The prevalence of stunting and wasting (cut-off point: less than 90% ht/age and less than 80% wt/ht) ranged in the public schools from 6.2 to 15.2% and 3.3 to 24.0%, respectively, whereas the figures for the private school were 2.3 and 3.5%, respectively. Much more obesity was found in the private school (18.0%) than in the state schools (0.8-6.2%). Nutritional problems seem to develop more severely in accordance with the increasing age of the children. Therefore it appears advisable to assess schoolchildren within the context of nutritional surveillance system.

Adolescent↗