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Biomedical subjects

S Schulz

Publications and source records attributed to S Schulz.

At least 181 records · Page 10Linked to original sources
PubMed1991

The expanding family of guanylyl cyclases.

The guanylyl cyclase receptor family contains members that exist in both the particulate and soluble fractions of cell homogenates. Soluble forms of the enzyme recognize EDRF (nitric oxide) or similar molecules, while diversity within the extracellular domain of the plasma membrane forms has resulted in a series of guanylyl cyclases that are specifically activated by different ligands. David Garbers and colleagues describe the recent cloning of some of these molecules.

Animals↗
PubMed1990

Guanylyl cyclase is a heat-stable enterotoxin receptor.

Plasma membrane forms of guanylyl cyclase have been shown to function as natriuretic peptide receptors. We describe a new clone (GC-C) encoding a guanylyl cyclase receptor for heat-stable enterotoxin. GC-C encodes a protein containing an extracellular amino acid sequence divergent from that of previously cloned guanylyl cyclases; however, the protein retains the intracellular protein kinase-like and cyclase catalytic domains. Expression of GC-C in COS-7 cells results in high guanylyl cyclase activity. In addition, heat-stable enterotoxin from E. coli, but not natriuretic peptides, causes marked elevations of cyclic GMP and is specifically bound by cells transfected with GC-C. The enterotoxin fails to elevate cyclic GMP in nontransfected cells or in cells transfected with the natriuretic peptide/guanylyl cyclase receptors. These results show that a heat-stable enterotoxin receptor responsible for acute diarrhea is a plasma membrane form of guanylyl cyclase.

1-Methyl-3-isobutylxanthine↗
PubMed1990

[Ways of tooth conservation by surgical techniques].

Based upon innovations in the past 20 years regarding material--as well as surgical techniques indications are given for surgical conservation of teeth, in addition questions of current interest referring to root fillings are answered. Possible ways of tooth conservation by periodontal operations are shown. To conserve traumatically injured teeth guides for emergency treatment are given.

Humans↗
PubMed1990

[Are complications following plate osteosynthesis of the lower diaphyseal shaft unavoidable?].

Metal plate osteosynthesis of the tibial shaft is a difficult and technically demanding procedure. When strict indications are carefully observed very good results can be obtained, but it must be pointed out that numerous complications may also be entailed. Between 1977 and 1987 a total of 447 operatively treated diaphyseal fractures of the lower limb were included in two studies of metal plate osteosynthesis. Whereas in study I (1977-1980) method-associated complications were detected in 24 cases out of a total of 87 (27.6%), including 9 cases of osteomyelitis alone, the second study, performed between 1981 and 1987 (126 cases), showed that the frequency of complications was drastically lower, with 18 cases (14.3%) even including minor complications. This is especially striking when it is borne in mind that osteomyelitis occurred in 2 cases only (1.6%) in study II. The lower number of complications is reflected by considerably shorter hospital stays, shorter periods of disability, and a lower number of disability pensions. The decline in the frequency of serious complications was primarily due to a decrease in the proportion of patients with open fractures treated with plate osteosynthesis from nearly 50% to 19%. In accordance with other publications it was confirmed that damage to the soft tissues of the lower limb is the decisive factor in postoperative and inflammatory complications. The results obtained show that plate osteosynthesis of diaphyseal fractures of the lower limb, particularly in cases of first- or second-degree closed fractures, involves only a low risk of complications. When indications are strictly observed, this method can be thoroughly recommended, especially for B group (wedge) fractures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[The rescue station--a multidisciplinary treatment unit in the hospital].

The creation of integrative organizational structures are seen as an objective requirement of medicine characterized by progress of knowledge and specialisation. For emergency cases the rescue station has stood the test as a multidisciplinary unit of the hospital. This thesis is confirmed by experiences obtained from practical work in the Frankfurt/Oder District Hospital and by discussions in the "Working Group Rescue Station" of the "Society of Emergency Medicine of the GDR." In order to realize the function of the rescue chain as well as the multidisciplinary motivation, intensive quantitative and qualitative promotion of rescue stations is required.

Emergency Service, Hospital↗
PubMed1989

The primary structure of a plasma membrane guanylate cyclase demonstrates diversity within this new receptor family.

Atrial natriuretic peptide (ANP) binds directly to a plasma membrane form of guanylate cyclase (GC-A), stimulating the production of the second messenger cyclic GMP. We show that a second guanylate cyclase/receptor (GC-B) exists, with distinctly different specificities for various natriuretic peptides. A cDNA clone encoding GC-B was isolated by low-stringency screening of a rat brain cDNA library using GC-A cDNA as a probe. The deduced amino acid sequence of GC-B is 78% identical with GC-A within the intracellular region, but 43% identical within the extracellular domain. Cyclic GMP concentrations in cells transfected with GC-A were half-maximally elevated at 3 nM ANP, 25 nM brain natriuretic peptide (BNP), and 65 nM atriopeptin 1, while 25 microM ANP, 6 microM BNP, and greater than 100 microM atriopeptin 1 were required for half-maximal stimulation of GC-B. The potencies of natriuretic peptides on GC-A and GC-B activity are therefore markedly different; furthermore, despite the specificity of GC-B for BNP, the relatively high BNP concentration required to elicit a response suggests the possible presence of a more potent, unidentified natural ligand.

Amino Acid Sequence↗
PubMed1989

A membrane form of guanylate cyclase is an atrial natriuretic peptide receptor.

Atrial natriuretic peptide (ANP) is a polypeptide hormone whose effects include the induction of diuresis, natriuresis and vasorelaxation. One of the earliest events following binding of ANP to receptors on target cells is an increase in cyclic GMP concentration, indicating that this nucleotide might act as a mediator of the physiological effects of the hormone. Guanylate cyclase exists in at least two different molecular forms: a soluble haem-containing enzyme consisting of two subunits and a non-haem-containing transmembrane protein having a single subunit. It is the membrane form of guanylate cyclase that is activated following binding of ANP to target cells. We report here the isolation, sequence and expression of a complementary DNA clone encoding the membrane form of guanylate cyclase from rat brain. Transfection of this cDNA into cultured mammalian cells results in expression of guanylate cyclase activity and ANP-binding activity. The ANP receptor/guanylate cyclase represents a new class of mammalian cell-surface receptors which contain an extracellular ligand-binding domain and an intracellular guanylate cyclase catalytic domain.

Amino Acid Sequence↗
PubMed1989

[The prognosis of autologous tooth transplants in orthodontic treatment planning].

Autogenous tooth transplantation is an alternative treatment for preserving continuity of the dental arch following early loss of teeth. The prognosis of transplants determines the indication as compared with other methods of space closure. Transplanted buds of upper premolars as well as of lower third molars continue their root growth. The clinical and roentgenological analysis of 81 autogenously transplanted upper canines, following different operative procedures, indicates, that 50% of the transplants remain in situ for five years and only 25% remain in situ longer than six years. The statistical chances of survival of vitally transplanted, apicoectomied teeth are more favourable. Short-term prognosis is determined by inflammatory bone and/or tooth resorption due to odontogenic infection or occlusal trauma. Long-time prognosis is determined by different forms of tooth resorption. Regular radiographic examination as reveal early odontogenic infections which can then be treated endodontically. The doubtful prognosis necessitates strict indications.

Adolescent↗
PubMed1989

Prognostic significance of vimentin positivity in formalin-fixed renal cell carcinomas.

The aim of the present study was to determine whether vimentin immunoreactivity was of prognostic relevance using the PAP-method on formalin-fixed tissue from 94 renal cell carcinomas (RCC). The vimentin expression was compared with tumour stage, histological grade of malignancy, and survival data. In 28 cases (30%), the tumour cells showed a vimentin positivity. This group showed a more unfavourable prognosis than the vimentin-negative group. Differences were also seen in stage T 3 tumours. The percentages of vimentin-positive cases increased with the grade of malignancy. Vimentin-positive cases showed a particularly unfavourable course in the G 3-group of carcinomas. In individual cases, the prognostic value of vimentin expression is limited by a decreased sensitivity and specificity. In addition, the presence of immunoreactivity apparently is not independent of conventional histological criteria of tumour grading.

Adult↗
PubMed1989

Comparison of energy expenditure by the doubly labeled water technique with energy intake, heart rate, and activity recording in man.

Average daily energy expenditure determined by the doubly labeled water technique (dlwEE) was compared in six subjects (aged 20-30 y) over 2 wk under usual living conditions; average food energy intake and energy expenditure estimated from individual diary records of physical activity. In addition, energy expenditure was estimated from 24-h heart rate recordings carried out on two randomly chosen days of the 2-wk period. The group means of the dlwEE were 1.94 +/- 0.24 (means +/- SD) times larger than resting metabolic rate (= 1.94 met) and nearly identical to the average daily energy intake (1.93 +/- 0.23 met). Energy expenditure estimated from the diaries of activity and from the 24-h heart rate recording varied between 1.67 and 2.24 met depending on the calculation procedure. The dlwEE (1.94 +/- 0.24 met) is much higher than that recently determined for sedentary people (1.25 met) and thus explains that young students may achieve body weight balance with a relatively high daily food energy intake.

Adult↗
PubMed1989

The guanylate cyclase/receptor family of proteins.

Guanylate cyclase, which catalyzes the formation of cGMP from GTP, exists in both the soluble and particulate fractions of cells. At least two different cellular compartments for the particulate enzyme exist: the plasma membrane and cytoskeleton. The enzyme form found in the soluble fraction is a heterodimer that can be regulated by free radicals and nitrovasodilators, whereas the membrane form exists as a single-chain polypeptide that can be regulated by various peptides. These peptides include resact and speract obtained from eggs and atrial natriuretic peptides (ANP). The species of guanylate cyclase present in cytoskeletal fractions resists solubilization with non-ionic detergents; its structural properties are not yet known. cDNAs encoding the membrane form of guanylate cyclase have been isolated from different tissues and species, and in all cases the DNA sequences predict a protein containing a single transmembrane domain. The carboxyl (intracellular) domain is highly conserved from sea urchins through mammals, whereas the extracellular domain (amino terminus) varies considerably. The predicted amino acid sequences demonstrate that the membrane form of guanylate cyclase is a member of a diverse and complex family of proteins that includes a low molecular weight ANP receptor, protein kinases, and the cytoplasmic form of guanylate cyclase. cDNA encoding a membrane form of the enzyme from mammalian tissues has been expressed in cultured cells, and the expressed guanylate cyclase specifically binds ANP and is activated by ANP. The membrane form of guanylate cyclase, then, serves as a cell surface receptor, representing the first recognized protein to directly catalyze formation of a low molecular weight second messenger in response to ligand binding.

Amino Acid Sequence↗
PubMed1989

[Comparative microbiological, macro- and microscopic and x-ray findings in iatrogenic perforation of the maxillary sinus depending on the time of its lancing].

To determine whether the inflammation afflicting the sinus mucosa shortly after oroantral communication is due to an injury or an infection, microbiological studies of two biopsy preparations each were performed simultaneously in 20 patients with the diagnosis: radix in antro. As a rule, notwithstanding the time of oroantral communication aerobe micro-organisms corresponding to the local conditions of oral and nasal flora. Primary asepsis of the sinus mucosa being assumed, an infection of the sinus maxillary has to be taken into account only one hour after the dislocation of a root of the tooth into the sinus maxillary. After six hours the infection will be followed by an inflammatory reaction.

Humans↗
PubMed1989

[Prostacyclin (PGI2) biosynthetic activity in variously differentiated neoplasms and the surrounding tissue].

For further elucidation of the connection between tumor differentiation, intensity of stroma reaction and the capacity of prostacyclin biosynthesis comparable investigations were performed on the PGI2 formation and the microscopic pattern of 10 tissue samples from naevus cell tumors, skin basalioma, oral pavement epithelium carcinoma and their direct adjoining region. The effects were compared with 10 tissues from healthy oral mucosa and facial skin. The results indicate that the PGI2 activity depends on the quantity of cells within the tissue. The various cells were stimulated in a different manner. The highest values of the PGI2 biosynthesis were found in cells of an inflammatory proliferation direct adjoining the oral pavement epithelium carcinoma. This shows a connection between tumor differentiation, intensity of stroma reaction and the activity of prostacyclin biosynthesis, possibly indicating a criterion of malignity for the prognosis of the tumor disease.

Basal Cell Carcinoma↗
PubMed1989

[Rapid typing of Escherichia coli K antigens using bacteriophages].

E. coli capsular (K) antigens are important virulence factors contributing to the development of urinary tract infections (UTI). Serotyping of these antigens is laborious and depends on the availability of respective antisera which are difficult to prepare because of the low immunogenicity of these polysaccharide antigens. The application of specific K phages are a big advantage. Two collections of E. coli strains (500 from Rostock, 214 from Erfurt) isolated from patients with UTI have been investigated with a set of ten K specific bacteriophages including phi 1, phi 2, phi 5, phi 7, phi 9, phi 12, phi 13, phi 20, phi 30 and phi 36. The K1 antigen has been found to be the most frequent capsular antigen (16.4% in Rostock; 12.2% in Erfurt) followed by K13/K20 in Erfurt (8.9%) and K5 in Rostock (8%) and Erfurt (7.5%). The collection of phages proved to be suitable for the detection of UTI associated K antigens covering the most common O serogroups found in UTI. The method appears to be simple, non-laborious and applicable for routine use.

Antigens, Bacterial↗
PubMed1988

Carboxylic acids from hairpencils of male Amauris butterflies (Lep.: Danainae).

63 Carboxylic acids were identified from the male hairpencils of four species of the genus Amauris (Lep.: Danainae), namely A. echeria (Stoll), A. hecate (Butler), A. ochlea (Boisduval) and A. albimaculata Butler. Straight chain saturated as well as unsaturated carboxylic acids, some of which containing an additional oxygen function, contribute to the species-specificity of the odour bouquets. Oxygenated fatty acids form a new class of insect volatiles, 5 of the 10 ketoacids found represent new natural products. (E)-7-Oxo-11-tetradecenoic acid is the main volatile component of the hairpencils of A. echeria, the species with the highest amount of oxygenated fatty acids (70% of the extractable volatiles). 9-Hydroxyoctadecanoic acid is a major compound in both A. ochlea and A. albimaculata while in A. hecate oxygenated carboxylic acids are present in minute amounts only.

Animals↗