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Biomedical subjects

K E Johansson

Publications and source records attributed to K E Johansson.

At least 19 recordsLinked to original sources
PubMed1992

Specificity of oligonucleotide probes complementary to evolutionarily variable regions of 16S rRNA from Mycoplasma hyopneumoniae and Mycoplasma hyorhinis.

Mycoplasma is the common name for the smallest free-living microorganisms, the Mollicutes. Mycoplasma hyopneumoniae is of great importance in veterinary medicine, causing enzootic pneumonia in pigs. M hyorhinis can cause polyserositis and may cause pneumonia in piglets. Oligonucleotides complementary to variable regions of 16S rRNA from these mycoplasmas were designed and used as probes for detection and identification of these mycoplasmas. The probe complementary to 16S rRNA of M hyorhinis gave a very weak cross-hybridisation with M hyosynoviae in filter hybridisation experiments, but not with any of the other porcine mycoplasmas tested. Three oligonucleotide probes complementary to M hyopneumoniae 16S rRNA were tested. One of the probes (Mhp6/30) was found to be specific to M hyopneumoniae, but the other two gave cross-hybridisation with M flocculare. Using the Mhp6/30 probe in direct filter hybridisation experiments, it proved possible to detect M hyopneumoniae in lung biopsies from experimentally infected pigs.

Animals↗
PubMed1992

Detection and identification of Mobiluncus species by direct filter hybridization with an oligonucleotide probe complementary to rRNA.

A hybridization assay for direct detection and identification of Mobiluncus species has been developed and tested. A [32P]-labelled synthetic oligonucleotide probe, complementary to a nucleotide sequence in the variable region V8 of Mobiluncus 16S ribosomal RNA, was utilized. One of the advantages of using rRNA as target molecule for the hybridization assays is the copy number of rRNA, which can be as high as 10(4), and that additionally three to six sites on the minus strand of the DNA gene can be utilized. This probe was found to be sensitive and to react with 62 of 68 tested typical or atypical Mobiluncus isolates. It was also specific, and was shown not to react with 96 tested unrelated bacterial species and isolates, including taxonomically closely related species like Actinomyces or Bifidobacterium spp., or with bacteria isolated from the vagina of both healthy persons with an undisturbed flora, as well as from patients suffering from the bacterial vaginosis syndrome (BV).

Bacteroidaceae↗
PubMed1991

Detection of Mycoplasma bovis and Mycoplasma agalactiae by oligonucleotide probes complementary to 16S rRNA.

The partial sequences of 16S rRNA from Mycoplasma bovis and M. agalactiae were determined by dideoxynucleotide sequencing using reverse transcriptase. Two oligonucleotides complementary to different evolutionary variable regions of 16S rRNA from these two species were synthesized. The oligonucleotides were end-labelled with 32P and used as probes in filter hybridization experiments with different bovine, caprine and ovine mycoplasmas as samples. One of the probes, complementary to a sequence of the V8-region of both M. bovis and M. agalactiae, did not cross-hybridize to any bovine, caprine or ovine mycoplasmas except M. bovigenitalium and M. californicum. This probe is thus not useful for analysis of bovine samples, but can be used for detection of M. agalactiae in samples from goats and sheep, since M. bovigenitalium and M. californicum have never been isolated from these hosts and M. bovis only occasionally. The other probe, complementary to a sequence of the V6-region of M. bovis, gave some cross-hybridization with M. agalactiae but not with bovine mycoplasmas. M. agalactiae has never been isolated from cattle and this probe is therefore useful for rapid screening of bovine samples for M. bovis.

Animals↗
PubMed1990

Analysis of caprine mycoplasmas and mycoplasma infections in goats using two-dimensional electrophoresis and immunoblotting.

Seven strains of mycoplasma have been characterized by two-dimensional polyacrylamide gel electrophoresis in combination with immunoblotting. The two-dimensional patterns of the strains were compared and similarities and differences are discussed. Hyperimmune rabbit antisera were used in the immunoblotting experiment to study the immunological cross-reactivity between the species. Sera from goats, naturally and experimentally infected with mycoplasma, were also used in the immunoblotting experiment to study the immune responses of the infected animals.

Animals↗
PubMed1990

Evaluation of different hybridization procedures for the detection of mycoplasma contamination in cell cultures.

Cell culture samples were analysed for mycoplasma contaminations with two different DNA probes which have been described earlier. One probe (the H900 probe), derived from the 23S rRNA gene of Mycoplasma hyorhinis, cross-hybridized with virtually all mycoplasmas (including the acholeplasmas). The other probe (the T2 probe), derived from a protein gene of Acholeplasma laidlawii, cross-hybridized with most acholeplasmas. The two probes were compared in three different direct filter hybridization procedures without previous isolation of DNA or RNA. One of the procedures, developed in the present study, gave the highest sensitivity in DNA-RNA hybridization but also worked satisfactorily in DNA-DNA hybridization. The sensitivity of the H900 probe in filter hybridization experiments was compared with the sensitivity of a commercial probe for detection of mycoplasma contaminations in cell cultures. The H900 probe was found to be at least 25 times more sensitive for all cell culture mycoplasmas except for A. laidlawii, for which they were equally sensitive.

Animals↗
PubMed1990

A new technique to define and clarify esophageal motor disorders.

Ambulatory 24-hour esophageal manometry was applied to analyze motility in 12 normal subjects and 9 patients with chest pain and dysphagia caused by diffuse esophageal spasm (DES). Pain episodes characterized by nonperistaltic activity occurred in 7 of 9 patients. A score based on 10 variables of the motility pattern differentiated patients from normal subjects and quantitated the severity of the disorder. Ambulatory motility monitoring was prospectively performed in 8 normal subjects and 37 patients: 8 with DES, 13 with hypertensive contractions, and 16 with a nonspecific disorder on standard manometry. The score was positive in 6 of 8 patients with DES and negative in all normal subjects (accuracy 87 percent). Nine of the 13 patients with hypertensive contractions (70 percent) and 6 of 16 with nonspecific disorders (38 percent) had a pathologic score reflecting a dysmotility as severe as DES. Ambulatory esophageal manometry is a more physiologic way to identify a motor disorder than standard manometry and has the potential to improve selection of patients for a surgical myotomy.

Adult↗
PubMed1988

The lower esophageal sphincter in health and disease.

The ability of the lower esophageal sphincter to protect the esophageal mucosa from exposure to gastric juice depends on its resting pressure, length exposed to abdominal pressure, and overall length. Mechanical incompetency of the sphincter can occur when one or more of these components fail. The purpose of this study was to measure manometrically the normal percentile values for these components, and to identify the point differentiating a mechanically competent from an incompetent sphincter. The results show that a mechanically incompetent sphincter can be identified by a sphincter pressure below the 2.5 percentile, an abdominal length below the fifth percentile, and an overall length below the 2.5 percentile of normal values. Sixty percent of the patients with documented increased esophageal exposure to acid gastric juice had a mechanically incompetent sphincter.

Adolescent↗
PubMed1988

Indications, surgical technique, and long-term functional results of colon interposition or bypass.

Over a 17-year period, 92 patients with esophageal disease underwent colon interposition or bypass, with each operation performed by the same surgeon. The indication was cure of cancer in 20 patients, relief of dysphagia in 55 (cancer in 17 patients and benign in 38), loss of gastrointestinal (G.I.) continuity in ten, and tracheoesophageal fistula in seven patients (malignant in five, benign in 2). The thirty-day operative mortality rate was 5%, and the hospital mortality rate was 9%. Graft necrosis occurred in seven of 92 patients, four of whom later underwent a successful second reconstruction. Thirteen patients required subsequent revisional surgery. In 85 patients, the left colon based on the inferior mesenteric artery was used, and in seven, the right colon was used. Technical insights were gained to help preserve the blood supply to the graft and improve its function in transporting food. Thirty-four patients were available for interview 2-17 years after operation (median of 5 years) 28 of whom had benign disease, and six of whom had malignant disease); 82% of the patients felt they were cured of their preoperative symptoms, 18% improved, and none worsened. Eighty-eight per cent of the patients were able to receive an unrestricted diet. All patients except one were satisfied with the results of surgery, and, asked what they would do if they had to make the choice again, all responded that they would have the operation. Twenty-six of the interviewed patients had their eating ability evaluated with a test meal and the transit time of a liquid and solid barium bolus measured. Compared to controls, patients with colon interpositions consumed a smaller capacity meal over a longer period of time and were not dependent on liquids to flush the food through the colon graft. A colon interposition provides good quality of deglutition, is very durable, and is the organ of choice for patients who require an esophageal substitute and are potential candidates for long survival.

Adult↗
PubMed1988

Esophageal body motor disturbances in gastroesophageal reflux and the effects of fundoplication.

Thirty-seven patients with gastroesophageal reflux disease (GERD) were included in an esophageal manometry study before and six months after fundoplication. The motility pattern of the body of the esophagus in the patient group was compared with that of 15 healthy controls. No differences in swallowing amplitudes were found between patients with different degrees of esophagitis or between GERD patients and controls. Peristaltic activity was slightly impaired in patients with endoscopic esophagitis compared with controls. No correlation was found between dysphagia and chest pain symptoms on the one hand and on peristaltic pattern and swallowing amplitudes on the other. It was concluded that conventional esophageal manometry has little to contribute to the investigation of symptoms such as non-burning chest pain and dysphagia in GERD. Effective anti-reflux surgery eliminates these symptoms with little influence on the esophageal motility pattern.

Adult↗
PubMed1988

Selective therapeutic approach to cancer of the lower esophagus and cardia.

The role of curative en bloc resection for carcinoma of the lower esophagus and cardia is still controversial. The experience with a selective approach in 52 patients with cancer in this location is reviewed. Thirty-two of the cancers were squamous cell, 13 adenocarcinoma, and seven adenocarcinoma associated with Barrett's esophagus. In 19, the tumor was not resectable and all of these patients died within a year. In 19 patients, a palliative resection could be done. Actuarial survival was 31% at 1 year. Only one patient was alive after 5 years. Initially, 16 patients with noncircumferential lesions on endoscopy and/or no evidence of spread to mediastinal lymph nodes on computed tomographic scan were considered to have potentially curable lesions. All were less than 75 years old and had a forced expiratory volume in 1 second greater than 1.5 L and a resting ejection fraction greater than 40%. A curative resection consisting of an en bloc thoracic esophagectomy, mediastinal lymphadenectomy, and an 80% gastrectomy with abdominal lymphadenectomy was performed in 14. The left colon was used to reestablish the gastrointestinal continuity. Two patients had more extensive disease discovered at operation, and the curative en bloc resection was abandoned. Absence of full wall penetration or involvement of four or fewer regional nodes, or both, was correctly predicted by preoperative and intraoperative staging in 86% of the patients. Operative mortality of a curative en bloc resection was 7% (1/14), and the actuarial survival rates were 76%, 66%, and 53% at 1, 2, and 5 years. Inferences are made from these results on tumor characteristics associated with survival, the extent of resection necessary for cure, the difficulty of accomplishing a curative en bloc resection by the transhiatal approach, the contraindication to curative en bloc resection, and the need for a surveillance program for patients with Barrett's esophagus.

Adenocarcinoma↗
PubMed1987

Cloning and expression of Acholeplasma laidlawii membrane acyl proteins in Escherichia coli.

Many integral membrane proteins in Acholeplasma laidlawii are enriched in hydrophilic amino acid residues and covalently modified with fatty acids. In order to understand how these proteins are inserted and anchored in the bilayer, we have cloned several of the major A. laidlawii proteins in Escherichia coli: 900 recombinant clones containing 4-kbp DNA fragments, inserted into the BamHI site of the plasmid pAT 153, were screened with antibodies. With antimembrane antibodies, 26 positive clones were detected, and with a mixture of five different monospecific antibodies, another 7 clones were obtained. Immunological analysis of the colonies in situ verified that antigens for A. laidlawii membrane proteins D12, T2, T3, T4a, and unidentified proteins were produced in separate clones. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting showed several fragments [25 to 94 kilodalton (kDa)] for each of these proteins, some of which were even visible on Coomassie Blue-stained gels. It is concluded that A. laidlawii membrane proteins can be efficiently expressed in E. coli.

Acholeplasma laidlawii↗
PubMed1986

Selective acylation of membrane proteins in Acholeplasma laidlawii.

In membranes of the cell-wall-less prokaryote Acholeplasma laidlawii most proteins are of the integral type. A substantial fraction of these proteins are enriched in hydrophilic amino acid residues. Approximately 20 different major as well as minor proteins were found to be covalently modified with acyl chains. The same set of proteins are acylated when cells are grown in different fatty-acid-supplemented media. In individual proteins the ratio of palmitoyl/oleoyl acyl chains was 12-14 times larger than the acyl chain ratio in polar membrane lipids. The transmembrane protein D12 has close to two acyl chains per molecule. Proteins T2 and T4a, localized in the outer and inner leaflet of the membrane, respectively, occur each as pairs with a difference in relative molecular mass within each pair of approximately 2000. Each of these proteins as well as the other acyl proteins, except the light form of T4a, has close to one acyl chain per molecule. The extent of acylation was increased for certain proteins and decreased for others by treatment with globomycin or phenethylalcohol. The relative amounts of the T2 and T4a pairs were affected by these drugs. It is concluded that the mechanism of acylation is different from that in Escherichia coli lipoprotein and Bacillus penicillinase. The mean hydrophobicity [Kyte & Doolittle (1982) J. Mol. Biol. 157, 105-132] of the A. laidlawii acyl proteins are similar to those of other bacterial acyl proteins but significantly lower than for non-acylated integral membrane proteins, supporting an anchoring function of the acyl chains. The number of membrane acyl proteins in A. laidlawii and two other mycoplasmas are at least twice that in other bacteria.

Acholeplasma laidlawii↗
PubMed1986

Double replica electroblotting: a method to produce two replicas from one gel.

Electroblotting is a method by which proteins or nucleic acids, separated by electrophoresis, are transferred, also by electrophoresis, from a gel to a so-called transfer medium, e.g a nitrocellulose membrane. In some experiments, it is desirable to be able to obtain more than one replica from each gel and it has now proved possible to produce two replicas, which are almost identical, from one gel. This is achieved by applying one membrane on each side of the gel and change the direction of the current several times in such a way that the efficient transfer time is short in the beginning of the electroblotting and is increased for each cycle. This procedure will be referred to as 'double replica electroblotting'. Proteins were transferred at 100 V and the duration of an experiment with 2 h efficient transfer time in each direction was 7 h. The gel was more efficiently depleted of proteins after double replica electroblotting as compared to ordinary electrotransfer in one direction. Cathodically migrating proteins are also trapped on the membranes with this technique. Double replica electroblotting was used to produce two replicas from ordinary sodium dodecyl sulfate polyacrylamide gels as well as from 2-dimensional gels.

Collodion↗
PubMed1986

Double-blind crossover study of ranitidine and placebo in gastro-oesophageal reflux disease.

The effect of 150 mg ranitidine twice daily was compared with placebo by the double-blind crossover technique (8 weeks twice) in patients with gastro-oesophageal reflux (paired comparison in 38 patients). Ranitidine was superior to placebo with regard to effect on symptoms, improvement of oesophagitis as assessed by endoscopy and biopsy, and decrease of oesophageal acid hypersensitivity. The symptomatic response to ranitidine was, however, unsatisfactory in more than half of the cases. When symptomatic responders taking ranitidine (R) were compared with non-responders (NR), there was no difference with regard to the severity of oesophagitis or frequency of positive acid perfusion tests before or after the 8-week treatment. NR were younger and more often had endoscopic signs of incompetence of the cardia and gastric prolapse. Ranitidine is an efficient drug in patients with reflux disease. It cannot be expected that mechanical problems in the hiatal region will be influenced by ranitidine, which is probably why half the patients did not respond.

Adult↗
PubMed1986

Maintenance treatment with ranitidine compared with fundoplication in gastro-oesophageal reflux disease.

The study comprises 31 patients with gastro-oesophageal reflux disease who received 8 weeks' treatment with ranitidine. Sixteen of the patients received in addition maintenance treatment with ranitidine (150 mg twice daily) for another 6 months, and fundoplication was performed on 15 patients. There was a significant improvement in endoscopic and histologic findings, a decrease in gastric acid secretion, and a reduction of symptoms during short-term treatment with ranitidine. No further improvement was seen in any of the factors after half a year of ranitidine. After surgery the total reflux time during 24 h decreased to practically zero, all patients had normal endoscopic findings and negative acid perfusion tests, and reflux symptoms had disappeared completely. Anti-reflux surgery was superior to treatment with ranitidine. Reflux oesophagitis is therefore not improved any further by a half year's treatment with ranitidine beyond what is achieved with short-term therapy.

Adult↗
PubMed1986

Oesophagitis, signs of reflux, and gastric acid secretion in patients with symptoms of gastro-oesophageal reflux disease.

In a study comprising 100 patients referred to a surgical clinic with symptoms suggestive of gastro-oesophageal reflux disease the value of different diagnostic procedures was investigated. Positive acid perfusion and 24-h pH tests were the commonest findings. Forty-nine per cent showed a normal oesophageal mucosa or diffuse oesophagitis at endoscopy. The severity of heartburn and regurgitation did not differ between patients with normal oesophageal mucosa and oesophagitis of various severities. The severity of macroscopic oesophagitis was significantly correlated to the total reflux time, the presence of reflux or a hiatal hernia at radiology, an open cardia or reflux at endoscopy, pressure transmission or reflux and low lower oesophageal sphincter pressure at manometry. Gastric hypersecretion was found in 66% of the patients. Gastric acid secretion was not correlated to the severity of oesophagitis or to the findings at 24-h pH test. In patients with severe oesophagitis the sensitivity for radiologic, manometric, and endoscopic signs of incompetence of the gastro-oesophageal junction was 94%.

Adult↗
PubMed1986

Oesophageal reflux tests, manometry, endoscopy, biopsy, and radiology in healthy subjects.

The aim was to study the exposure time of acid during 24 h at two different oesophageal levels in 15 healthy subjects and its relation to other kinds of oesophageal findings. Five centimetres above the lower oesophageal sphincter the total reflux time was 0.2% (0-1.3%), and at the 15-cm level it was 0.1% (0-0.7%). A standardized compression test during manometry and radiologic examination showed that no subject had reflux. Hiatus hernia was provoked at the radiologic examination in four subjects, one of whom also had a widened hiatus. At endoscopy, one subject had a hiatus hernia and slightly granulated oesophageal mucosa. Biopsy specimens showed slight basal cell hyperplasia in one case. Bleeding in the dermal papillae or a few intraepithelial leukocytes were seen in eight cases, findings that might be due to endoscopic trauma. Without any history of gastrointestinal disorders, gastrooesophageal reflux was minimal under standardized conditions, although hiatus hernia and mild changes in biopsy specimens could be seen.

Adult↗