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F Suter

Publications and source records attributed to F Suter.

At least 91 records · Page 5Linked to original sources
PubMed1984

The light-harvesting polypeptides of Rhodopseudomonas sphaeroides R-26.1. I. Isolation, purification and sequence analyses.

Four low-molecular-mass polypeptides were isolated and purified from chromatophore membranes of Rhodopseudomonas sphaeroides blue-green mutant R-26.1 by a combination of gel filtration and ion-exchange chromatography in organic solvents. On dodecyl sulfate polyacrylamide gels, the purified polypeptides comigrate with bands LH-1, LH-2 and LH-3 known to be related to the antenna-pigment-protein complexes. The complete primary structures were elucidated by automated Edman degradation of the intact polypeptides and of overlapping C-terminal fragments obtained after chemical cleavage at tryptophan and methionine residues. The C-termini were verified by hydrazinolysis and, in one case where an overlapping C-terminal fragment could not be obtained, by digestion with carboxypeptidase A. The four polypeptides show a tripartite structure: i.e. a polar N-terminal region is separated from a polar C-terminal region by a segment of about 21 predominantly hydrophobic amino-acid residues. All hydrophobic segments contain a characteristic conservative histidine residue. The C-terminal region is reduced to only a few amino acids in the two polypeptides which together form band LH-3, i.e. LH-3A and LH-3B. Their extended N-terminal region is rich in charged residues and contains an additional conserved histidine residue close to the beginning of the hydrophobic segment. These properties place LH-3A and LH-3B into subgroup (beta-polypeptides: B 870-beta and B 850-beta, respectively). LH-1 and LH-2 appear to form another subgroup (alpha-polypeptides: B 870-alpha and B 850-alpha, respectively) as suggested during a search for conservative elements within their sequences (structural basis for classification). N-Terminal analyses carried out with intact antenna-pigment-protein complexes revealed the following: (i) LH-1 and LH-3 are associated with the B 870 complex in Rp. sphaeroides 24.1 (wild type), (ii) the same polypeptides are almost exclusively present in chromatophore membranes of Rp. sphaeroides R-26, a blue-green mutant which absorbs at 870 nm, (iii) LH-2 and LH-3B are the constituent polypeptides of the B 800-850 complex of Rp. sphaeroides 2.4.1 and of the spectrally altered B 850 complex isolated from the blue-green mutant R-26.1 which absorbs at 860 nm. This mutant contains LH-2 and LH-3B along with LH-1 and LH-3A and apparently is able to form both types of antenna complexes.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1983

[Current clinical aspects of leptospirosis].

Leptospirosis is still endemic in the Po valley. It has an extremely protean clinical picture. In a series of 79 cases diagnosed at Pavia in the period 1970-79 hepatonephritic forms were the most common (29.1%), followed by febrile or pseudo-influenza forms (25.3%), hepatitis (20.2%), nephritis (17.8%), and meningitis (7.6%). Febrile hepatonephritis was always accompanied by the most severe pictures. Timely antibiotic management with penicillin or ampicillin, and above all the early use of peritoneal dialysis (carried in 10 subjects) enable a final cure to be obtained even in these cases. The only death in that series did not appear to be ascribable to the disease itself.

Adolescent↗
PubMed1983

The complete amino-acid sequence of the large bacteriochlorophyll-binding polypeptide from light-harvesting complex II (B800-850) of Rhodopseudomonas capsulata.

The large bacteriochlorophyll-a-binding polypeptide of the light-harvesting complex II (B800-850), having an apparent Mr with sodium dodecyl sulfate/polyacrylamide electrophoresis of 10000, has been isolated and purified from intracytoplasmic membranes of the phototrophically negative mutant strain Y5 of Rhodopseudomonas capsulata. The primary structure of this polypeptide has been determined. The polypeptide consists of 60 amino acid residues yielding an Mr of 7322. The hydrophobic stretch in positions 16-35 with a histidine in position 31 might be of importance for interaction with bacteriochlorophyll. The C-terminal part is also hydrophobic while the N-terminal part consists of hydrophilic amino acids. The polarity of the total amino acids was determined to be 28.3%.

Amino Acid Sequence↗
PubMed1983

The complete amino-acid sequence of both subunits of phycoerythrocyanin from the thermophilic cyanobacterium Mastigocladus laminosus.

The amino-acid sequences of both subunits of phycoerythrocyanin from the thermophilic cyanobacterium Mastigocladus laminosus have been determined. The alpha-subunit consists of 162 amino-acid residues and has a molecular mass of 18200 Da. The beta-subunit is 171 residues long and has a molecular mass of 19600 Da. The tetrapyrrole chromophores are bound at position 84 in the alpha- and beta-subunits and at position 155 in the beta-subunit. The homology between the two subunits is 21%. The homologies between the phycoerythrocyanin subunits and the corresponding subunits of C-phycocyanin and allophycocyanin are 63% and 26% for the alpha-subunits and 67% and 36% for the beta-subunits, respectively. Secondary structure predictions were calculated for all six subunits of the phycobiliproteins from M. laminosus. The most conservative regions of the biliproteins were found in segments C-terminal to the chromophore-binding sites.

Amino Acid Sequence↗
PubMed1983

N-terminal sequences of subunits L and M of the photosynthetic reaction centre from Rhodospirillum rubrum G-9+. Separation of the subunits by gel filtration on hydroxypropylated Sephadex G 100 in organic solvents.

A new method has been developed by which subunits L and M of the photosynthetic reaction centre from Rhodospirillum rubrum G-9+ can be obtained in pure form, starting form freeze-dried chromatophore membranes. The method employs extraction into a mixture of chloroform/methanol and gel permeation chromatography on a column of hydroxypropylated Sephadex G 100. Cross-contamination of the purified subunits was less than 5% (mol/mol), as estimated by manual Edman degradation. Automated Edman degradation has been carried out with both subunits in a liquid-phase sequencer. 36 amino-acid residues of subunit L and 50 residues of subunit M could be unequivocally identified. In both cases, the sequence analyses came to a premature end as the signal sudden by dropped to the level of the accidental fluctuations of the phenylthiohydantoin-derivatives background. This effect is explained by the unusual susceptibility to peptide bond cleavage of certain threonine residues which probably underwent N leads to O acyl shift during the cleavage reactions. The N-terminal sequences have been compared to those of subunits L and M of the photosynthetic reactions centre from Rhodopseudomonas sphaeroides R-26 (sutton, M.R., Rosen, D., Feher, G. & Steiner, L.A. (1982) Biochemistry 21, 3842-3849). The homology among subunits L is close to 90% and thus markedly higher than that among subunits M (32%). This finding indicates a pre-eminent role of subunit L in the primary events of photosynthetic energy conversion.

Amino Acid Sequence↗
PubMed1983

Structure and function of L-lactate dehydrogenases from thermophilic and mesophilic bacteria. III) The primary structure of thermophilic lactate dehydrogenase from Bacillus stearothermophilus. Hydroxylamine-, o-iodosobenzoic acid- and tryptic-fragments. The complete amino-acid sequence.

Based on the partial sequence of the cyanogen bromide fragments [Tratschin, J.D., Wirz, B., Frank, G. and Zuber, H. (1983) Hoppe-Seyler's Z. Physiol. Chem. 364, 879-892], the amino-acid sequence of thermophilic lactate dehydrogenase from B. stearothermophilus was completed by the preparation and sequencing (sequenator, carboxypeptidase A and Y) of further overlapping fragments. Suitable peptide fragments were obtained by lactate dehydrogenase cleavage with hydroxylamine, o-iodosobenzoic acid and trypsin. The polypeptide chain of thermophilic lactate dehydrogenase from B. stearothermophilus consists of 317 amino-acid residues. While sequence homology with mesophilic lactate dehydrogenase of higher organisms reaches 35%, it is substantially higher with this mesophilic enzyme of bacillae (greater than 60%, B. megaterium, B. subtilis). The secondary structure elements and amino-acid residues of the active site of thermophilic lactate dehydrogenase deducted from primary structure data were compared with those from the mesophilic enzyme, the same was done for the internal sequence homology at the nucleotide-binding units. A comparative structure analysis (matrix system) based on the primary structure data of thermophilic enzyme should provide insight into the characteristic structure differences between thermophilic and mesophilic lactate dehydrogenase.

Amino Acid Sequence↗
PubMed1982

Severe meningitis due to Listeria monocytogenes. A review of 40 cases in adults.

During a 10-yr period, 40 cases of severe Listeria monocytogenes meningitis were observed. All patients showed consciousness disturbances and 27 of them (68%) focal neurologic signs. Cranial nerve palsies were common (57%). Early general seizures (13 patients) and presence of underlying disease (12 patients) were associated with a high mortality rate. Although the management of antibiotic therapy is open for discussion, chloramphenicol (used in 7 patients) seems to be more effective than other drugs.

Adult↗
PubMed1979

[Clinical considerations on posttraumatic osteitis].

Posttraumatic bone infection very often signifies a life threatening complication. However, it must no longer be accepted that amputation of the afflicted limb be the logical treatment of such a complication. A surgeon who offers the advantages of operative treatment of a fracture to his patient must also be able to control its complications. Osteitis can be treated with a good chance of success. In our clinic 29 bone infections were treated, 13 of them healing without substantial restrictions, 7 with distinct discomfort and 4 with arthrodesis, i.e. 83% healed. However, the treatment may require months and may necessitate further operative interventions. The transfer of such a patient from an acute care hospital to a high altitude clinic offers -- besides the medical and psychological advantage of a continuous long-term treatment plan -- the climatic conditions of sun and high altitude air which apparently act very favorably on the healing process of chronic infections. Of course, the possibility of competent surgical interventions must exist. Thus, with proper therapy the disastrous chain of errors beginning mainly with poor initial care through insufficient treatment can be broken.

Adolescent↗
PubMedDate not supplied

Lipid-based amphotericin B in the treatment of cryptococcosis.

Amphotericin B is the only antifungal drug which, despite its dose-limiting toxicity, can be given intravenously when an aggressive treatment is required. In an attempt to reduce the drug toxicity while retaining its therapeutic efficacy, new formulations of amphotericin B have been developed. The most promising have employed lipid vehicles such as liposomes. Three lipid-based amphotericin B formulations have been developed by pharmaceutical companies and are under active clinical investigation. Efficacy and safety data of these derivatives in animals and humans are reviewed, with particular concern to cryptococcal infection. The authors' experience with a small unilamellar liposomal amphotericin B formulation, AmBisome, in the primary therapy of cryptococcosis is reported. Nine AIDS patients affected with cryptococcosis, seven of whom had meningitis, were given AmBisome (3 mg/kg/day) for 3-6 weeks. Complete response was obtained in six patients, marked improvement in two, and failure in one. AmBisome was well tolerated and shortened the time to clinical and mycological response suggesting a further improvement in the management of cryptococcosis in AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Zidovudine and thymus humoral factor gamma-2 in the treatment of HIV infection: preliminary clinical experience.

A case-control, prospective, open-label, clinical trial to evaluate efficacy and safety of a combined zidovudine/Thymus Humoral Factor Gamma-2 (THF) therapy in HIV-infected subjects was conducted in 13 patients. Twenty-six patients were included as controls receiving only zidovudine. The two groups of patients were matched according to sex, age, CDC stage of HIV infection, number of CD4+ T cells and type of previous opportunistic infections (if any) and all patients and controls were naive for antiretroviral therapy at the moment they entered the trial. The observation period was protracted up to 47 months (mean 28 +/- 13 months). No significant difference was observed between the two groups as far as surrogate markers of HIV disease progression are concerned. However, patients receiving zidovudine and THF showed a lower number of opportunistic complications. Only one patient in this group progressed to manifest AIDS while 9 of 18 controls presented disease progression. Four patients died in the case group, all of them were CDC stage IV at admission, and 15 of 26 died in the control group (all CDC stage IV at admission, and four patients who presented disease progression during the study period). Survival time was increased in the case group. The exact immunological effect of thymus hormones in HIV infection has still to be elucidated, but a possible therapeutic role of these agents is foreseeable.

Adult↗
PubMedDate not supplied

Antiviral potency of HAART regimens and clinical success are not strictly coupled in real life conditions: evidence from the MASTER-1 study.

PURPOSE: To compare in a real clinical setting the largely unknown midterm clinical effectiveness of two protease inhibitor (PI)-based highly active antiretroviral therapy (HAART) regimens with different potency and tolerability profiles in naïve patients. METHOD: This study was a multicenter, open-label, randomized trial in naïve patients with less than 400 CD4+ cell count/microL, regardless of viral load. Treatment arms were hard gel capsule saquinavir (HGC-SQV)-based HAART (Arm A), with an expected more favorable tolerability profile, and indinavir (IDV)-based HAART (Arm B), with more potent virologic activity. While viro-immunological surrogate markers and World Health Organization (WHO) grade III toxicity (secondary endpoints) were regularly monitored, primary endpoints of the study were clinical and defined as any AIDS-defining event, AIDS-related death, WHO grade IV toxicity, drop outs, and protocol violations. RESULTS: 262 consecutive patients were enrolled in the study from March 1, 1997 to December 31, 1997, in 24 different Italian clinical centers (132, Arm A; 130, Arm B). After 24 months of follow-up, patients who were enrolled in Arm B showed a significantly higher rate of virological success (75% had viremia below 500 copies/mL, CI = 12.9%, in the on-treatment analysis) and immunological gain (mean CD4+ cell count increase of 274 CD4+ cells/microL, SD = 234) when compared to patients enrolled in arm A (57%, CI = 15.5% and 223 CD4+ cells/microL, SD = 192; p =.0353 and.026, respectively). Despite the significant difference observed in surrogate markers, the number of total primary endpoints did not differ in the two groups (55 out of 132 in Arm A vs. 58 out of 130 person-years in Arm B; p =.86). CONCLUSION: Our results suggest that, after 24 months of follow-up in a real clinical setting, a PI-based HAART induces significant clinical benefits in naïve patients even in the absence of a complete suppression of viral replication. However, the long-term clinical impact of the possible accumulation of viral mutations in the presence of low-grade viral replication remains to be elucidated.

Adult↗