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Biomedical subjects

H Schmitz

Publications and source records attributed to H Schmitz.

At least 109 records · Page 6Linked to original sources
PubMed1994

Follicular dendritic cells retain HIV-1 particles on their plasma membrane, but are not productively infected in asymptomatic patients with follicular hyperplasia.

During HIV-1 infection, extensive alterations can be observed in the germinal centers (GCs) of lymphatic tissue. The initial hyperplasia of GCs is followed by disintegration and involution of these structures. The process is accompanied by progressive destruction of the network of follicular dendritic cells (FDCs). We investigated whether or not the destruction of GCs is caused by HIV-1 infection of FDCs in vivo. FDCs were purified by FACS or magnetic cell sorter (MACS) from enlarged lymph nodes (LNs) of four asymptomatic HIV-1-infected patients with persistent generalized lymphadenopathy. In situ hybridization demonstrated positive signals for HIV-1 RNA on the cell membrane of FDCs. Virus particles attached to the dendritic network could be demonstrated by electron microscopy, but budding was not seen. Furthermore, proviral DNA was detected by nested PCR (NPCR) in limiting dilution assays of FACS-purified FDCs (up to 1.0 x 10(4) cells) in only one cell fraction. In comparison, proviral DNA could be found in 5.0 x 10(3) to 2.5 x 10(5) FACS-purified Th cells obtained from peripheral blood and in 7.5 x 10(5) to 2.5 x 10(4) Th cells from LN of the same patients. In conclusion, FDCs retain HIV-1 particles on their cell membrane during HIV-1 infection, but the progressive destruction of FDC in vivo is probably not caused by a productive infection of FDCs with HIV-1.

Cell Membrane↗
PubMed1994

Oblique section 3-D reconstruction of relaxed insect flight muscle reveals the cross-bridge lattice in helical registration.

In this work we examined the arrangement of cross-bridges on the surface of myosin filaments in the A-band of Lethocerus flight muscle. Muscle fibers were fixed using the tannic-acid-uranyl-acetate, ("TAURAC") procedure. This new procedure provides remarkably good preservation of native features in relaxed insect flight muscle. We computed 3-D reconstructions from single images of oblique transverse sections. The reconstructions reveal a square profile of the averaged myosin filaments in cross section view, resulting from the symmetrical arrangement of four pairs of myosin heads in each 14.5-nm repeat along the filament. The square profiles form a very regular right-handed helical arrangement along the surface of the myosin filament. Furthermore, TAURAC fixation traps a near complete 38.7 nm labeling of the thin filaments in relaxed muscle marking the left-handed helix of actin targets surrounding the thick filaments. These features observed in an averaged reconstruction encompassing nearly an entire myofibril indicate that the myosin heads, even in relaxed muscle, are in excellent helical register in the A-band.

Animals↗
PubMed1994

Recovery of T-lymphocytes for adoptive immunotherapy by lymphapheresis of HIV-infected patients without alterations of virological, immunological or clinical parameters.

We performed repeated continuous flow cytaphereses (CFC) on 13 asymptomatic HIV-1-infected patients to study the feasibility of cell separation procedures to recover high yields of peripheral blood T-lymphocytes for adoptive immunotherapy in HIV-infected patients and to determine immunological and virological alterations following such procedures. A mean yield of 6.23 x 10(9) lymphocytes could be obtained by each cytapheresis, containing 1.82 x 10(9) CD4+, 3.23 x 10(9) CD8+ T-lymphocytes and 8.39 x 10(6) CD34+ peripheral progenitor cells. The CD4/CD8 ratio (mean 0.53, SD +/- 0.15) in the cell samples reflected the distribution of the lymphocyte subsets in vivo. Absolute lymphocyte counts decreased at a mean of 404/mm3 (25%) immediately after CFC but were replaced from the extravascular pool within 1 h. The CD4/CD8 ratios, p24-antigenaemia, HLA-DR expression and neopterin levels did not change significantly after cell separation. No alteration of the number of T-cells with integrated proviral DNA copies (1/10(3) to 1/10(6)) could be detected in peripheral T-helper cells by PCR after lymphapheresis. We conclude that high yields of peripheral T-lymphocytes can be obtained by continuous flow lymphapheresis for cell-mediated immunotherapy, without deterioration of virological or immunological parameters in HIV-infected patients. The separated T-cells are fully replaced from extravascular pools after 1 h.

CD4-CD8 Ratio↗
PubMed1994

Antibodies of symptomatic human immunodeficiency virus type 1-infected individuals are directed to the V3 domain of noninfectious and not of infectious virions present in autologous serum.

The present study was designed to determine the antibody specificity for the human immunodeficiency virus type 1 (HIV-1) V3 domains of infectious and noninfectious virions present in the serum of AIDS patients. To accomplish this, HIV-1 was isolated in the presence of autologous antibodies from the serum samples of six AIDS patients in HIV-1-negative donor peripheral blood mononuclear cells by short-term cultivation. The isolated virus, defined as the infectious cell-free virus (iCFV), was characterized by sequence analysis of the proviral DNA coding for the third hypervariable (V3) region of the external glycoprotein gp120. This was carried out by amplifying and cloning the V3 region. In all six cases studied, 20 randomly selected V3 clones derived from the proviral DNA of the iCFV, 20 clones from patient cell-free virus, and 20 clones from cell-integrated virus were sequenced to study the distribution and frequency of the intrapatient virus population. The number of major virus variants in the six patients ranged from three to nine. The various V3 sequences found in the AIDS patients showed the typical amino acid pattern of the syncytium-inducing and non-syncytium-inducing viral phenotypes characteristic for the late stage of infection. However, only one patient-specific iCFV variant was detected within the 20 V3 clones analyzed per virus isolation. For the six patients a total of 34 V3-loop variants, either iCFV or non-iCFV, was observed. All 34 V3-loop sequences were expressed as glutathione-S-transferase fusion proteins (V3-GST). The autologous antibody response to the V3-GST fusion proteins was studied by Western immunoblot analysis. A strong antibody response to almost all non-iCFV V3-GST proteins was found in the sera of the six patients. In contrast, the autologous antibody response to the six iCFV V3 loops was undetectable (in four patients) or very faint (in two patients) compared with that to the non-iCFV V3 loops. Five of the six iCFV loops showed positively charged amino acids at positions strongly associated with the syncytium-inducing phenotype. These findings suggest that our in vitro isolation system selects for virions which are not recognized by V3-specific antibodies and are infectious both in vitro and in vivo.

Acquired Immunodeficiency Syndrome↗
PubMed1994

[Virus diseases in patients returning from the tropics].

The high density of populations and insufficient sanitary conditions increases the risk to acquire viral diseases in tropical areas. This holds true for ubiquitous as well as for regional viral infections. Hepatitis and AIDS are found worldwide, but play a dominant role in tropical areas. Classical tropical viral infections are zoonoses. They are primarily infections of nonhuman vertebrates (e.g. rodents) and of arthropod vectors and can be transmitted to man. According to the clinical outcome these viral infections can be divided into three groups: influenza-like disease with arthralgia, encephalitis and hemorrhagic fevers. The majority of infections belong to the first group, followed by encephalitis cases. Viral hemorrhagic fevers are rare in visitors of tropical areas. Antibody detection is the method of choice in the diagnosis of tropical viral infections. In special situations (e.g. Lassa fever) the direct detection of the virus by PCR can be helpful. Tests for the detection of arboviruses, filoviruses and arenaviruses are only performed at a few centers worldwide.

Animals↗
PubMed1994

[Pathological-anatomical findings after serologic and molecular biologic evidence of Hantaan virus infection].

Post-mortem findings in a girl aged 2 years and 4 months who had been infected with Hantaan virus are reported. The child fell ill with acute renal failure in her 8th month of life and had to be subjected to chronic dialysis. There was a progressive cardiac insufficiency. Specific IgG and IgM antibodies to Hantaan virus were demonstrated by serology from the 18th month of life. Autopsy revealed endomyocardial fibrosis and cardiomegaly. Hantaan RNA could be demonstrated in formalin-fixed, paraffin-embedded specimens of lung, liver and spleen tissue by means of RT-PCR followed by DNA sequencing. A possible association between the Hantaan virus infection and the pathological findings in the heart are discussed.

Antibodies, Viral↗
PubMed1994

Endocrine effects of Lycopus europaeus L. following oral application.

Lycopus extracts are used in folk medicine for the treatment of hyperthyroid symptoms. Diverse effects on the pituitary thyroidal system as well as on the pituitary gonadal system could be confirmed in experimental studies. But till now endocrine effects of Lycopus extracts in experimental animals were observed after parenteral application only. Therefore in this investigation an ethanolic extract of Lycopus europaeus was applied orally to rats, diverse endocrine parameters were measured between 3 and 24 h later and the effects compared to an i.p. treated group. The plant extract given p.o. caused a long lasting (for a period of more than 24 h) decrease of T3 levels, presumably as a consequence of a reduced peripheral T4 deiodination. A pronounced reduction of T4 and thyroid stimulating hormone (TSH) concentrations was observed 24 h after application of the test solution by gavage. The luteinizing hormone (LH) decrease as well as the TSH decrease, which was pronounced in spite of reduced T4 and T3 levels indicate a central point of attack of the plant extract. Differences in the biological activity in dependence on the route of application may be explained e.g. by differences in absorption of plant constituents.

Animals↗
PubMed1993

Optimizing follicular dendritic cell isolation by discontinuous gradient centrifugation and use of the magnetic cell sorter (MACS).

Follicular dendritic cells (FDC) contribute minimally to the total cell population of lymphatic tissue. In order to obtain higher numbers of viable FDC with only a small fraction of contaminating cells the following procedure was developed. Subsequent to the usual mechanical and enzymatical digestion of human tonsils, single cells were layered on top of a discontinuous bovine albumin gradient and centrifuged at 8500 x g. The suspension collected from the 1.052-1.030 interphase contained an average of 10.5% FDC. Next, the preparation was subjected to a new step involving separation of FDC previously treated with biotin-labelled KiM4 monoclonal antibody, raised against FDC, and attached via biotin-streptavidin bonding to streptavidin-conjugated paramagnetic beads. Purification on a magnetic cell sorter (MACS) yielded 3.3-10.1 x 10(6) cells with an average FDC content of 78.4%. The viability and morphology of the resulting FDC population was examined using trypan blue staining or electron microscopy. This technique will permit in vitro studies and long term cultures with FDC isolated from human lymphatic tissue.

Antibodies, Monoclonal↗
PubMed1993

An improved technique for the diagnosis of viral retinitis from samples of aqueous humor and vitreous.

We applied the technique of DNA amplification with the polymerase chain reaction to nine aqueous humor and five vitreous samples from HIV-1-infected patients with clinically diagnosed cytomegalovirus retinitis. For the amplification, recently published primers specific for herpes simplex virus (HSV), varicella zoster virus (VZV) and cytomegalovirus (CMV-1) were used. Additionally, a newly developed primer pair specific for the main immediately early gene of CMV (CMV-2) was selected and compared with the published one. All primers were tested on noninfected and HSV-, VZV- and CMV-infected human fibroblast cell culture supernatant, thereby excluding cross-reactivity of the chosen primers. In none of 13 aqueous humor and six vitreous samples of healthy controls was any viral DNA amplified. Using the CMV-1 primers, we detected CMV DNA in five of nine aqueous humor and three of five vitreous samples amplifying a DNA fragment 435 base pairs in length. With the CMV-2 primers, we detected a CMV DNA fragment with a length of 110 base pairs in eight of nine aqueous humor and in four of five vitreous samples. Additionally, CMV DNA was found in three of nine urine and two of nine saliva specimens. Both CMV and HSV DNA were amplified in one aqueous sample. Varicella DNA was not detected in any of the specimens. Thus, the polymerase chain reaction is more sensitive than other comparable diagnostic tests and may provide an alternative to conventional virus isolation and in situ hybridization techniques for the laboratory diagnosis of viral ocular disease.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Effects of nitrendipine on blood pressure, renin-angiotensin-system and atrial natriuretic peptide in hypertensive type I diabetic patients.

In this study, the effects of a six week treatment with the calcium channel blocking agent nitrendipine were assessed in 20 hypertensive type I diabetic patients who received a single oral dose of 20 mg daily. Plasma concentrations of atrial natriuretic peptide (ANP), plasma renin activity (PRA) and active renin, aldosterone, glycosylated hemoglobin (HbA1) and fructosamines were determined at the beginning and the end of the study. Interactions of these endocrine parameters with blood pressure behaviour were analyzed by a correlation matrix. In response to the drug treatment, the blood pressure was significantly lowered from 158.0/97.2 to 145.7/88.2 mmHg. The plasma concentrations of ANP were also significantly reduced from 106.8 to 89.7 pg/ml. There were no changes in serum aldosterone, while PRA and active renin exhibited a significant increase following the six week treatment. HbA1 and fructosamines remained unaltered. There were no significant correlations for ANP and blood pressure values, as well as for ANP and PRA or aldosterone. We did find, however, a significant correlation of the ANP values with the difference of the systolic blood pressure levels pre- and post-treatment. These data fully confirm the blood pressure lowering properties of this calcium channel blocker and its possible interference with steroidogenesis, since the effects of increased PRA on aldosterone secretion were clearly blunted. The lowering of plasma ANP levels may represent a decreased ANP secretion due to calcium channel blockade or might also be due to the natriuretic effects of nitrendipine, thus allowing ANP levels to decline as a function of lessened sodium retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effect of long-term spleen dialysate (Solcosplen) administration on plasma lipids and lipoproteins in early postmenopausal women.

A total of 46 early postmenopausal women with elevated levels of total cholesterol, triglycerides, low-density lipid (LDL) cholesterol and lowered high density lipoprotein cholesterol (HDL) cholesterol was treated with spleen dialysate (Solcosplen), 2 x 2 tablets daily for 6 months. Serum estradiol levels rose from 42.3 +/- 15.4 pg/ml to 60.6 +/- 23.6 pg/ml and the Kupperman Index decreased significantly after 6 months of treatment. Also, a significant decrease of total cholesterol, triglycerides, LDL cholesterol, and an increase of HDL cholesterol was observed. The changes showed no correlation with the estradiol concentration and no side-effects were evident. Solcosplen is recommended as a beneficial therapy for women in the early postmenopause.

Anticholesteremic Agents↗
PubMed1993

Human Kupffer cells infected with HIV-1 in vivo.

Blood monocytes as well as cells of the macrophage-phagocytic system in several tissues are targets for HIV-1 in vivo and in vitro. However, the data on HIV-1 infection of liver macrophages/Kupffer cells (KCs), which make up the main pool of fixed-tissue macrophages, is controversial. We therefore studied HIV-1 infection of KCs in vivo. Blood and liver tissue was obtained from seven AIDS patients shortly after death. Liver tissue was minced before processing. Cell suspensions were further purified by density gradient centrifugation, stained with anti-CD14 (blood monocytes) or anti-macrophage 25F9 (KCs), and separated by fluorescence-activated cell sorting (FACS). These highly purified cell populations were then analyzed for HIV-1 proviral DNA by the polymerase chain reaction (PCR). By performing PCR on FACS-purified cell populations, we could show that both KCs and peripheral blood monocytes were HIV-1-infected in 3 of 7 patients. KCs harbored HIV-1 proviral DNA only if peripheral blood monocytes were infected. These data show that KCs of the liver are infected with HIV-1 in vivo.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[Vitex agnus castus extract in the treatment of luteal phase defects due to latent hyperprolactinemia. Results of a randomized placebo-controlled double-blind study].

The efficacy of a Vitex agnus castus preparation (Strotan capsules) was investigated in a randomized double blind study vs. placebo. This clinical study involved 52 women with luteal phase defects due to latent hyperprolactinaemia. The daily dose was one capsule (20 mg) Vitex agnus castus preparation and placebo, respectively. Aim of the study was to prove whether the elevated pituitary prolactin reserve can be reduced and deficits in luteal phase length and luteal phase progesterone synthesis be normalized. Blood for hormonal analysis was taken at days 5-8 and day 20 of the menstrual cycle before and after three month of therapy. Latent hyperprolactinaemia was analysed by monitoring the prolactin release 15 and 30 min after i.v. injection of 200 micrograms TRH. 37 complete case reports (placebo: n = 20, verum: n = 17) after 3 month of therapy were statistically evaluated. The prolactin release was reduced after 3 months, shortened luteal phases were normalised and deficits in the luteal progesterone synthesis were eliminated. These changes were significant and occurred only in the verum group. All other hormonal parameters did not change with the exception of 17 beta-estradiol which rouse up in the luteal phase in patients receiving verum. Side effects were not seen, two women treated with the Vitex agnus castus preparation got pregnant. The tested preparation is thought to be an efficient medication in the treatment of luteal phase defects due to latent hyperprolactinaemia.

Adult↗
PubMed1991

[Gonalgia: treatment with therapeutic local anesthesia. Results of a controlled comparative study versus diclofenac].

The effectiveness and tolerance of therapeutic local anesthesia (TLA) with lidocaine was compared with those of oral diclofenac in a controlled, open, randomized study involving 76 patients with gonalgia due to gonarthrosis or patellar chondropathy. During the course of the three-week (maximum) treatment, the summed score of pain at rest, pain on movement, and restricted mobility, taken as the target parameter of effectiveness, decreased significantly more markedly (p = 0.008) under TLA, than under diclofenac. Side effects involving mainly the gastrointestinal tract occurred significantly more frequently in the diclofenac group (p = 0.012). The results of this study indicate that in the treatment of localized joint pain of degenerative genesis, TLA with lidocaine is superior to NSAID treatment in terms of effectiveness and tolerance.

Adult↗
PubMed1991

Structural and functional studies on the human hepatic interleukin-6 receptor. Molecular cloning and overexpression in HepG2 cells.

cDNAs coding for the human hepatic interleukin-6 receptor (IL-6-R) have been isolated from a library made from poly(A) RNA of dexamethasone-treated human hepatoma cells (HepG2). We found the hepatic IL-6-R to be identical to the one expressed by leucocytes. A polyclonal antiserum was raised in rabbits against the IL-6-R protein expressed in Escherichia coli. Although the entire IL-6-R protein was used for immunization, only antibodies to the cytoplasmic domain of the IL-6-R were obtained. It is demonstrated by affinity cross-linking and subsequent immunoprecipitation with antibodies against the ligand as well as against the receptor that the cloned cDNA codes for the functional IL-6-R on HepG2 cells. When the hepatic IL-6-R cDNA was overexpressed in HepG2 cells, these cells became more sensitive to low concentrations of IL-6 with respect to the induction of gamma-fibrinogen mRNA.

Amino Acid Sequence↗