PubMed Health⌕ Search

Biomedical subjects

F Albrecht

Publications and source records attributed to F Albrecht.

At least 19 recordsLinked to original sources
PubMed2004

Illness and disability in Danish Chronic Fatigue Syndrome patients at diagnosis and 5-year follow-up.

OBJECTIVE: Evaluation of the life impact of Chronic Fatigue Syndrome (CFS) over 5 years. METHODS: Thirty-three adult patients meeting 1988 and 1994 CDC case criteria answered identical questionnaires at diagnosis and 5 years later, when a retrospective questionnaire was also completed. RESULTS: Work disability was very high and increased further, social isolation remained high, emotional adjustment improved. There were increased problems with reading and with allergies. Two measures of improvement were used: The relation between these measures was weak. Length of illness, extent of disability and emotional adjustment were poorly related to measures of improvement. Average illness scores were unchanged, but most individuals improved in some ways while worsening or remaining the same in others. Only one participant (3%) neared recovery, one other was substantially better but still severely disabled. CONCLUSION: CFS patients exhibit severe, long-term functional impairment. Substantial improvement is uncommon, less than 6%. Allergies and aspects of cognition may worsen, emotional adjustment often improves.

Activities of Daily Living↗
PubMed1999

Post-liver transplantation lymphoproliferative disorders with and without infusions of donor bone marrow cells.

Donor bone marrow cells (DBMC) infusions have been used in an attempt to decrease the untoward effects of immunosuppressive treatment and to improve immunocompetence in the post-liver transplantation (PLT) period. Between March 1987 and July 1996, 558 orthotopic liver transplantations were performed at Jackson Memorial Hospital/University of Miami. Of these, 164 patients (29%) received 10 x 10(8) DBMC/Kg using various schedules. All patients received similar immunosuppressive therapy. After a minimum follow up of 1 year, five cases of Posttransplant Lymphoproliferative Disorder (PTLD) were diagnosed in patients without DMBC (1.3%, 5/394) when compared with none (0/164) in patients who received DBMC (p = 0.15, Fisher). Four patients had malignant lymphoma and one a diffuse atypical lymphoproliferative disorder. All lymphomas were non-Hodgkin's B-cell type, three diffuse large cell lymphoma, and one mixed cell lymphoma. All PTLD tested positive for EBV by in situ hybridization. Lymphomas occurred at 2, 4, 6 months and 4 years PLT. The outcome was poor with one patient diagnosed at autopsy while two patients died a few days after diagnosis. An 8-year-old girl is the only long-term survivor (> 5 years) after a partial response to combination chemotherapy and radiation therapy. The patient with diffuse atypical lymphoproliferative disorder died 3 months later. All patients with PTLD had histologic evidence of liver rejection. Although there is no statistical significant difference between the two groups, a larger cohort of patients will determine the significance of DBMC in preventing PTLD. We believe that the infusion of cytotoxic donor T cells found in the DBMC might suppress EBV-related lymphomagenesis.

Adolescent↗
PubMed1997

[Current information on the composition and breed distribution of urinary stones in dogs].

5706 canine urinary stones were analyzed by means of infrared spectroscopy from 1984-1996. The stones were sent in together with epidemiologic data (breed, age, sex, localisation of the stones, type of stone removal, stone frequency etc.) by more than 800 veterinarians from Germany, the Netherlands, Austria, and Switzerland. Irrespective of stone type, urinary stones were observed in almost all breeds, but small breeds like dachshound, poodle, terrier, schnauzer, and pekingese have a higher tendency to form stones. With 59.5% struvite is the most frequent stone type, followed by cystine with 15.5%. Cystine stones are becoming less frequent during the observation time, whereas the share of calcium oxalate (14.2%) and ammonium urate (6.0%) stones remains unchanged. The latter stone types are found predominantly in specific breeds. The stone formation appears predominantly at the age of 7. Male dogs form stones twice as often as female dogs. 98% of the stones were located in the lower urinary tract. About 90% of the urinary stones required surgical treatment.

Animals↗
PubMed1994

Monoclonal IgA class-switch variants against bacterial surface antigens: molecular forms and transport into murine respiratory secretions.

The present study describes a new model for passive immunization of the respiratory tract with IgA in comparison to other isotypes. Monoclonal IgA-isotype-switch variants were isolated from different IgG-producing hybridoma clones specific for surface epitopes of bacterial respiratory tract pathogens. Analysis of the molecular form of the IgA variants revealed the simultaneous production of monomeric, dimeric and higher polymeric IgA by a single-cell line with predominance of the polymeric forms. The specificities of the IgA variants were identical to the parent IgG antibodies as demonstrated by inhibition experiments. The IgA variant antibodies were separated into monomers and polymers by gel filtration. Intravenous injection of the different molecular forms of IgA and of IgG into mice were used to investigate the transport characteristics of IgA into murine upper and lower respiratory tract secretions by the physiological route in comparison to IgG. Polymeric IgA variant, monomeric IgA variant and IgG were detected in immunologically active form in both nasal secretion and bronchoalveolar fluid as evidenced by binding to their antigens in an enzyme-linked immunosorbent assay. The relative contribution of the specific exogenous monoclonal IgA and monoclonal IgG to total IgA and IgG, respectively, was determined in secretions. Comparison of the secretion to serum transport ratios clearly indicates selective transport of polymeric IgA variant into nasal secretions relative to IgG parent antibody. Molecular and functional characteristics of the IgA variants make them ideal for passive mucosal immunization experiments and identification of protective epitopes in mucosal immunity.

Animals↗
PubMed1993

Identification of dopamine1A receptors in the rat small intestine.

Dopamine receptors have been localized to several tissues outside the central nervous system including the kidney and mesenteric vessels. To determine if there are dopamine1 receptors within the small intestine, homogenates of the antimesenteric halves of the entire jejunum and ileum of adult rats were prepared and competitive inhibition studies and Scatchard analysis were performed at room temperature using 125I-SCH 23982 and SCH 23390. The specific binding of 125I-SCH 23982 to the intestinal tissue homogenates was rapid, saturable with ligand concentration, and reversible. Analysis of the Scatchard plots revealed a single class of receptors with an apparent dissociation constant of 10.77 +/- 2.32 nM and maximum receptor density of 1.37 +/- 0.34 fmole/mg protein. Emulsion autoradiography performed using 125I-SCH 23982 on antimesenteric sections of the rat small intestine revealed that the dopamine1 receptors are located on cells at the base of the intestinal crypts. Two dopamine1 subtypes (D1A and D1B) have been identified by molecular biological techniques. Using a ribonuclease protection assay we found expression of the D1A receptor gene in the small intestinal tissue. These studies are the first to identify, characterize, and localize receptors for the endogenous catecholamine, dopamine, within the rat small intestine and to confirm the expression of the D1A receptor gene.

Animals↗
PubMed1992

Ontogeny of DA1 receptor-mediated natriuresis in the rat: in vivo and in vitro correlations.

The natriuretic and diuretic effects of dopamine are attenuated in the young. Because dopamine has actions on receptors (e.g., adrenergic, serotonin) other than dopamine, we studied a novel dopamine agonist, pramipexole, which has a selectivity to both DA1 and DA2-receptor subtypes. Intravenous administration of pramipexole resulted in a dose-related (1, 10, and 100 micrograms.kg-1.min-1) increase in urine flow and absolute and fractional sodium excretion and a decrease in mean arterial pressure (MAP) in three groups of rats studied. Pramipexole induced a greater decrease in MAP in 6- to 7- (n = 5) and 9- to 16- (n = 6) than in 3- to 4-wk-old (n = 8) rats; the natriuresis and diuresis were greatest in 12- to 16- and least in 3- to 4-wk-old rats. The renal effects of pramipexole were mainly due to actions at the DA1 receptor, since these effects were completely blocked by the coinfusion of a DA1 antagonist, SKF 83742. To explore further a cause of the attenuated natriuretic effect of pramipexole in the young, we studied the effect of a selective DA1-receptor agonist, fenoldopam, on amiloride-sensitive 22Na+ uptake in renal brush-border membrane vesicles. The 3-s amiloride-sensitive uptake was inhibited (45%) by fenoldopam (5 x 10(-5)M) in 9- to 16- (n = 6) but not in 3- to 4-wk-old (n = 5) rats. These studies suggest that the attenuated natriuretic effect of dopamine in the young is in part due to decreased DA1 action on the brush-border membrane Na(+)-H+ exchanger.

Aging↗
PubMed1990

The signal transducer for the dopamine-1 regulated sodium transport in renal cortical brush border membrane vesicles.

We have reported the presence of dopamine-1 (DA-1) and dopamine-2 (DA-2) receptors in renal brush border and basolateral membranes. DA-1 agonists stimulate adenylate cyclase (AC) and phospholipase C (PLC) activity in both membranes. Moreover, the ability of a DA-1 agonist (fenoldopam) to stimulate PLC activity is independent of AC activity. A DA-2 agonist (LY171555) by itself was without effect and did not enhance the ability of the DA-1 agonist to stimulate PLC activity. The DA-1 but not DA-2 agonists inhibit Na+/H+ exchange activity in brush border membrane vesicles (BBMV) and Na+/K(+)-ATPase activity in basolateral membranes. However, cAMP inhibits, while protein kinase C (presumably via PLC activity) stimulates, Na+/H+ exchange activity. We therefore determined the effect of DA-1 agonists on Na+/H+ exchange activity when PLC or AC activity was blocked using neomycin or dideoxyadenosine, respectively. The drugs were incubated with minced renal cortex prior to preparation of BBMV by differential centrifugation and MnCl2 precipitation. Enrichment of BBMV was not affected by drug treatment. The Na+/H+ exchange activity was assessed by measuring amiloride (1 mmol/L) sensitive 22Na+ uptake in BBMV (pHi = 5.5, pHo = 7.5, Nai+ = O, Nao+ = 1 mmol/L). Neomycin inhibited DA and DA-1-stimulated PLC activity in BBMV in a concentration dependent manner (10(-6) to 10(-4) mol/L). Neomycin (10(-4) mol/L) completely blocked the ability of DA and DA-1 agonist to stimulate PLC activity but had no consistent effect on DA-1 inhibited Na+/H+ exchange activity. Dideoxyadenosine inhibited DA and DA-1 simulated AC activity without affecting DA-1 stimulated PLC activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Dopamine inhibits Na(+)-H+ exchanger activity in renal BBMV by stimulation of adenylate cyclase.

To determine a renal tubular mechanism for the natriuretic effect of dopamine (DA) and DA-1 agonists, we measured Na(+)-H+ exchange activity (amiloride sensitive) in rat renal cortical brush-border membrane vesicles (BBMV). Renal cortical tissues were preincubated with ligands before BBMV preparation to study Na(+)-H+ exchange activity in the absence of the added ligands that may compete for ion binding sites of the exchanger. DA and DA-1 agonist-inhibited Na(+)-H+ exchange activity was concentration and time dependent. The inhibitory effect was not due to increased permeability, collapse of the proton gradient, or change in vesicle size and did not extend to Na(+)-glucose symport. DA-2 agonists had no effect, whereas alpha-adrenergic agonists increased Na(+)-H+ exchange activity. Kinetic analysis revealed that the DA-1 agonist inhibited Na(+)-H+ exchange activity by a noncompetitive process. 2',5'-Dideoxyadenosine inhibited adenylate cyclase activity and reversed the inhibitory effect of DA-1 agonist on the exchanger. H4, an isoquinoline sulfonamide, which inhibits protein kinase A, also reversed the inhibitory effect of DA-1 agonist on the exchanger. Thus the DA-1 agonist-mediated inhibition of Na(+)-H+ exchange activity in BBMV is a receptor-mediated adenylate cyclase-linked process.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1988

Picket-fence porphyrins as potential phototherapeutic agents.

The synthetic "picket fence" porphyrin, tetra(o-acetamidophenyl)porphine (TAc), as a biological photosensitizer has been evaluated both in vitro and in vivo in mitochondria from the R3230AC mammary tumor. Studies in vitro, consisting of incubation of mitochondria with TAc at a concentration of 4.0 micrograms/ml followed by photolysis, result in the inhibition of cytochrome c oxidase, proton translocating ATPase, succinate dehydrogenase, and malate dehydrogenase. The diminution in activity of the first three enzymes is approximately 2-fold greater than that seen with Photofrin II under the same conditions. Although TAc exists as four isolable atropisomers, no differences among these different forms were observed in their photosensitized inhibition of mitochondrial enzymes. Administration to tumor-bearing rats of TAc i.p. at a dose of 25 mg/kg did result in accumulation of porphyrin within the mitochondria of the R3230AC tumor as determined by subsequent irradiation of isolated mitochondria. The potential utility of TAc and related porphyrins in cancer phototherapy is discussed.

Animals↗
PubMed1983

Closure of osteochondral lesions using chondral fragments and fibrin adhesive.

In 75 knee joints of 46 adult rabbits osteochondral defects of 4 mm diameter were placed by a drill reaching the cancellous bone. Twenty-three defects were left untreated, or closed by collagen foam or fibrin adhesive, or a combination of both. Fifty-two defects were closed with very small autologous cartilage fragments and a special fibrin adhesive. The adhesive differed from commercially supplied types by digested alpha chain of fibrinogen for increase in concentration, and by the addition of alpha-2-macroglobulin as protease-inhibitor. In most cases small pieces of collagen foam were added for hemostasis. In the first group of 23 joints observed over up to 40 weeks, no hyaline cartilage was found histologically in any of the defects. In the second group a rapid proliferation of chondrocytes appeared with development of hyaline cartilage with alcianblue-positive matrix. It resembled juvenile cartilage in its histologic appearance and with regard to the induction of ossification. The phenomenon is interpreted as a "second adolescence" of the adult cartilage induced by the rich nutritional and oxygen supply from the cancellous vessels, which resembles the environmental conditions before the forming of subchondral cortical bone at the end of the growth period. This method enabled us to achieve a complete closure of defects by hyaline cartilage on the very level of the surrounding articular surface.

Animals↗
PubMed1983

[Angled 1/3-tubular plate for osteosynthesis of dislocated humeral fractures through the collum anatomicum].

Stable osteosynthesis of dislocated fractures of the head of the humerus by lag screws cannot be granted because the avascular head fragment is small. Alternatively the fixation can be performed by means of an angled 1/3-tubular plate with 8 holes. The plate is inserted similar to the condylar plate after preparing a seat with 3 drills of 2 mm ø. The angle-point depends on the diameter of the head fragment. The angle should be approximately 110 degrees. The free part is fixed to the shaft under tension. A successful case of total dislocation for more than one day is demonstrated where no head necrosis occurred.

Adult↗